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Abstract: Creatinine excretion rate (CER) indicates timed urine collection accuracy. Although equations to estimate CER exist, their bias and precision are untested and none simultaneously include age, sex, race, and weight.

Abstract: We sought to determine whether concurrently high levels of HDL cholesterol and CRP predict initial cardiovascular events in women, and to assess additional risk involving two genes encoding proteins involved in reverse cholesterol transport.

Abstract: Abstract.� Abbasi A, Corpeleijn E, van der Schouw YT, Stolk RP, Spijkerman AMW, van der A DL, Navis G, Bakker SJL, Beulens JWJ (University Medical Center Groningen, Groningen; University Medical Centre Utrecht, Utrecht; and National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands) Maternal and paternal transmission of type 2 diabetes: influence of diet, lifestyle and adiposity. J Intern Med 2011; doi: 10.1111/j.1365-2796.2011.02347.x. Objective.� Transmission of family history of type 2 diabetes to the next generation is stronger for maternal than paternal diabetes in some populations. The aim of the present study was to investigate whether this difference is explained by diet, lifestyle factors and/or adiposity. Methods.� We analysed 35�174 participants from the Dutch contribution to the European Prospective Investigation into Cancer and Nutrition, a prospective population-based cohort (aged 20-70�years) with a median follow-up of 10.2�years. Parental history of diabetes was self-reported. Occurrence of diabetes was mainly identified by self-report and verified by medical records. Results.� Amongst 35�174 participants, 799 incident cases of diabetes were observed. In age- and sex-adjusted analyses, hazard ratio (HR) and 95% confidence intervals (CIs) for diabetes by maternal and paternal diabetes were 2.66 (2.26-3.14) and 2.40 (1.91-3.02), respectively. Maternal transmission of risk of diabetes was explained by diet (9.4%), lifestyle factors including smoking, alcohol consumption, physical activity and educational level (7.8%) and by adiposity, i.e. body mass index and waist and hip circumference (23.5%). For paternal transmission, the corresponding values were 2.9%, 0.0% and 9.6%. After adjustment for diet, lifestyle factors and adiposity, the HRs for maternal (2.20; 95% CI, 1.87-2.60) and paternal (2.23; 95% CI, 1.77-2.80) transmission of diabetes were comparable. Conclusions.� Both maternal and paternal diabetes are associated with increased risk of type 2 diabetes, independently of diet, lifestyle and adiposity. The slightly higher risk conferred by maternal compared to paternal diabetes was explained by a larger contribution of diet, lifestyle factors and adiposity.

Abstract: Identification of genetic risk factors for albuminuria may alter strategies for early prevention of CKD progression, particularly among patients with diabetes. Little is known about the influence of common genetic variants on albuminuria in both general and diabetic populations. We performed a meta-analysis of data from 63,153 individuals of European ancestry with genotype information from genome-wide association studies (CKDGen Consortium) and from a large candidate gene study (CARe Consortium) to identify susceptibility loci for the quantitative trait urinary albumin-to-creatinine ratio (UACR) and the clinical diagnosis microalbuminuria. We identified an association between a missense variant (I2984V) in the CUBN gene, which encodes cubilin, and both UACR (P = 1.1 � 10(-11)) and microalbuminuria (P = 0.001). We observed similar associations among 6981 African Americans in the CARe Consortium. The associations between this variant and both UACR and microalbuminuria were significant in individuals of European ancestry regardless of diabetes status. Finally, this variant associated with a 41% increased risk for the development of persistent microalbuminuria during 20 years of follow-up among 1304 participants with type 1 diabetes in the prospective DCCT/EDIC Study. In summary, we identified a missense CUBN variant that associates with levels of albuminuria in both the general population and in individuals with diabetes.

Abstract: Recently we reported on a genetically predisposed protection from C-reactive protein (CRP) related mortality in dialysis patients carrying the functional CC-chemokine receptor 5 deletion 32 allele (CCR5�32) mutation. Since CCR5�32 is associated with a less pro-inflammatory immune response in mice, we hypothesized that the observed protection is (in part) due to a less pro-inflammatory cytokine profile.

Abstract: Experimental studies suggest a detrimental role for vasopressin in the pathogenesis of autosomal dominant polycystic kidney disease (ADPKD). However, it is unknown whether endogenous vasopressin concentration is associated with disease severity in patients with ADPKD.

Abstract: Prevention of progressive renal function loss and its complications remains the main challenge in clinical nephrology. Although current therapeutic strategies aiming at reduction of blood pressure and proteinuria often slow down deterioration of renal function, still many patients progress to end-stage renal disease. The development of novel pharmacological approaches for treatment of chronic kidney disease (CKD) is therefore instrumental. Here we review the renoprotective potential of vitamin D and its analogues. In CKD patients, vitamin D deficiency is common and progression of CKD is associated with low (active) vitamin D levels. Moreover, in animal models of CKD, treatment with vitamin D (analogues) alone or in combination with renin-angiotensin-aldosterone system (RAAS) blockade reduces proteinuria, glomerulosclerosis and tubulointerstitial fibrosis. Potential underlying mechanisms include suppression of the RAAS, modulation of immune cell function and direct protective effects on renal cells such as podocytes. Whether vitamin D analogues could further optimize existing therapies in human renal disease is currently under investigation.

Abstract: In the Western world, the majority of morbidity and mortality are caused by multifactorial diseases. Some risk factors are related to more than one type of disease. These so-called universal risk factors are highly relevant to the population, as reduction of universal risk factors may reduce the prevalence of several types of multifactorial disease simultaneously. Vitamin D deficiency is traditionally seen as an etiological factor in bone disorders such as rickets and osteomalacia. Recent studies also suggest a role for vitamin D deficiency in multifactorial disorders, including progressive renal function loss and cardiovascular disease; it is also a risk factor for frailty. The potentially pleiotropic effects of vitamin D analogues support the hypothesis that vitamin D deficiency is a universal risk factor. Here we review molecular actions of the vitamin D receptor (VDR), to identify mechanisms and pathways for vitamin D deficiency as a universal risk factor. To identify genes directly regulated by the VDR, we searched for genes containing vitamin D response elements (VDREs). A further refinement was made by selecting only VDRE-containing genes with documented modulation by VDR analogues in vivo. Our search yielded a limited number of factors possibly related to pleiotropic effects of vitamin D, including growth factors, hormones, inflammatory factors and factors related to calcium homeostasis. Results from observational, intervention and mechanistic studies indicate that vitamin D is a universal risk factor involved in diverse multifactorial conditions. Further exploration of the multifaceted actions of vitamin D may pave the way for disease-overriding intervention strategies.

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Abstract: Diabetic nephropathy is now the most common cause of end-stage renal failure in many countries of the world. Despite increasing implementation of preventive treatment, the chance that an individual diabetic patient will reach end-stage renal failure has been increasing rather than decreasing during recent decades. Current dietary habits in The Netherlands and the rest of the Western world are slowly shifting from relatively alkalinizing (e.g., potatoes and vegetables) toward more acidifying (e.g., rice and meat). Moreover, immigrants who consumed traditional diets in their homelands, usually adapt to Western dietary habits. This phenomenon of diet acculturation could, for instance, be involved in the up to 40 times higher chance of development of end-stage renal failure in association with diabetes in South-Asian immigrants compared with whites, in Western countries. High ingestion of nonvolatile acids with food increases susceptibility for progression to end-stage renal failure. These high dietary acid loads lead to compensatory increases in renal acid excretion and ammoniagenesis. The price paid for maintenance of acid-base homeostasis is renal tubulointerstitial injury, with subsequent decline in renal function and induction of hypertension. The tendency for metabolic acidosis that results from the changing dietary habits could be corrected by a shift toward more alkalinizing food. We hypothesize that promoting such a shift can prevent the epidemic of end-stage renal failure in diabetes.

Abstract: The association between cardiac failure and renal function impairment has gained wide recognition over the last decade. Both structural damage in the form of systemic atherosclerosis and (patho) physiological hemodynamic changes may explain this association. As regards hemodynamic factors, renal impairment in chronic heart failure is traditionally assumed to be mainly due to a decrease in cardiac output and a subsequent decrease in renal perfusion. This will lead to a decrease in glomerular filtration rate and a compensatory increase in tubular sodium retention. The latter is a physiological renal response aimed at retaining fluids in order to increase cardiac filling pressure and thus renal perfusion. In heart failure, however, larger increases in cardiac filling pressure are needed to restore renal perfusion and thus more volume retention. In this concept, in chronic heart failure, an equilibrium exists where a certain degree of congestion is the price to be paid to maintain adequate renal perfusion and function. Recently, this hypothesis was challenged by new studies, wherein it was found that the association between right-sided cardiac filling pressures and renal function is bimodal, with worse renal function at the highest filling pressures, reflecting a severely congested state. Renal hemodynamic studies suggest that congestion negatively affects renal function in particular in patients in whom renal perfusion is also compromised. Thus, an interplay between cardiac forward failure and backward failure is involved in the renal function impairment in the congestive state, presumably along with other factors. Only few data are available on the impact of intervention in volume status on the cardio-renal interaction. Sparse data in cardiac patients as well as evidence from cohorts with primary renal disease suggest that specific targeting of volume overload may be beneficial for long-term outcome, in spite of a certain further decrease in renal function, at least in the context of current treatment where possible reflex neurohumoral activation is ameliorated by the background treatment by blockers of the renin-angiotensin-aldosterone system.

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Abstract: Low physical activity (PA) is a risk factor for mortality in the general population. This is largely unexplored in renal transplant recipients (RTRs). We studied whether PA is associated with cardiovascular and all-cause mortality in a prospective cohort of RTR.

Abstract: Aldosterone, a steroid hormone with mineralocorticoid activity, is far more than merely a salt-and-water hormone. Aldosterone has a number of non-classical, mineralocorticoid receptor (MR)-mediated actions, including tissue remodeling, modulation of vascular tone and stimulating inflammation and fibrosis, which may fuel progression of end organ damage. Aldosterone breakthrough during blockade of the renin-angiotensin aldosterone system (RAAS) may explain why this treatment regimen only confers partial cardiovascular and renal protection. Of major interest, aldosterone is deleterious only if inappropriately high for its sodium status i.e. high aldosterone and high sodium. The mechanism of sodium dependence of aldosterone-induced renal and cardiovascular damage continues to fascinate. Aldosterone excess increases sodium and fluid retention and consequently increases blood pressure, which, in turn, mediates target organ damage. Moreover, blood pressure independent effects play a role with dissociation of low circulating and high tissue aldosterone levels during high sodium intake and possibly enhanced MR signaling. MR blockade is a valuable strategy, which has potency to halt the progressive end organ damage as observed during current treatments. In heart failure, MR blockade on top of RAAS blockade reduces hard clinical endpoints. Despite encouraging results on the intermediate endpoint proteinuria, long-term data on the efficacy and safety of MR blockade in preventing dialysis and/or cardiovascular endpoints in chronic kidney disease are still lacking. It is obligatory that future clinical studies on the effects of MR blockade on end-organ damage take into account the sodium status.

Abstract: BACKGROUND: Chronic kidney disease (CKD) typically extends over decades. Longitudinal monitoring of kidney function in CKD is thus of great importance. Here, we retrospectively evaluate use of the Modification of Diet in Renal Disease (MDRD) study and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations to monitor long-term course of kidney function and to identify individuals with progressive kidney function loss. METHODS: Patients were selected from our outpatient clinic for having four glomerular filtration rate measurements (mGFR, (125)I-iothalamate) and at least � 4 years of follow-up. Renal function slopes were obtained by within-individual linear regression. RESULTS: Sixty-five nondiabetic CKD patients (40 male, mean baseline age 44 ± 12 years) with a median (range) of 9 (4-16) mGFR measurements and a median follow-up of 11 (4-33) years were included. Both equations significantly underestimated mGFR/(BSA) at baseline and at the end of follow-up. mGFR slope was significantly underestimated by the MDRD study but not by CKD-EPI equation (slopes -1.41 ± 2.06, -1.07 ± 1.72 and -1.39 ± 1.77 mL/min/1.73m(2)/year, respectively). Sensitivity and specificity to identify progressive kidney function loss (mGFR/(BSA) slope > 1.5 mL/min/1.73m(2)/ year, n = 23) were 78 and 88% for the MDRD study and 91 and 80% for CKD-EPI equation. In the subgroup of progressors, both MDRD study and CKD-EPI equation underestimated the rate of mGFR loss (P < 0.05) CONCLUSIONS: Long-term course of mGFR is reasonably well estimated by CKD-EPI and slightly underestimated by MDRD study equation. Patients with progressive kidney function loss may, however, not be reliably identified, so caution is warranted when using these equations in clinical practice.

Abstract: Randomized clinical trials are expensive and time consuming. Therefore, strategies are needed to prioritise tracks for drug development. Genetic association studies may provide such a strategy by considering the differences between genotypes as a proxy for a natural, lifelong, randomized at conception, clinical trial. Previously an association with better survival was found in dialysis patients with systemic inflammation carrying a deletion variant of the CC-chemokine receptor 5 (CCR5). We hypothesized that in an analogous manner, pharmacological CCR5 blockade could protect against inflammation-driven mortality and estimated if such a treatment would be cost-effective.

Abstract: Background: Smoking in renal transplant recipients (RTR) is an acknowledged cardiovascular risk factor. It is, however, unclear whether smoking also increases the risk of graft failure (GF). Method: In this study, we prospectively assessed the association of current smoking versus past and never smoking with GF and mortality in 604 RTR (age 51.5 ± 12.1 years, 55% male). Results: At inclusion, 133 (22%) were current smokers, 255 (42%) were past smokers and 216 (36%) never smoked. During follow-up of 5.3 (4.7-5.7) years, 41 (7%) RTR experienced GF and 95 RTR (16%) died. Current smoking RTR had higher risk for GF compared to never smoking RTR (hazard ratio, HR = 3.3, 95% CI 1.5-7.1, p = 0.002). Past smoking RTR had similar risk of GF as never smoking RTR (HR = 1.1, 95% CI 0.5-2.6, p = 0.7). Current smoking RTR and past smoking RTR were at higher risk for death than never smoking RTR (HR = 2.1, 95% CI 1.1-3.8, p = 0.016, and HR = 2.4, 95% CI 1.4-4.0, p = 0.001, respectively). Conclusion: Smoking after renal transplantation is associated with risk for GF and mortality. Since past smoking is a risk factor for mortality but not for GF, smoking cessation may be beneficial to RTR in delaying GF in long term.

Abstract: Alcohol consumption is a moderately heritable trait, but the genetic basis in humans is largely unknown, despite its clinical and societal importance. We report a genome-wide association study meta-analysis of �2.5 million directly genotyped or imputed SNPs with alcohol consumption (gram per day per kilogram body weight) among 12 population-based samples of European ancestry, comprising 26,316 individuals, with replication genotyping in an additional 21,185 individuals. SNP rs6943555 in autism susceptibility candidate 2 gene (AUTS2) was associated with alcohol consumption at genome-wide significance (P = 4 � 10(-8) to P = 4 � 10(-9)). We found a genotype-specific expression of AUTS2 in 96 human prefrontal cortex samples (P = 0.026) and significant (P < 0.017) differences in expression of AUTS2 in whole-brain extracts of mice selected for differences in voluntary alcohol consumption. Down-regulation of an AUTS2 homolog caused reduced alcohol sensitivity in Drosophila (P < 0.001). Our finding of a regulator of alcohol consumption adds knowledge to our understanding of genetic mechanisms influencing alcohol drinking behavior.

Abstract: Properdin binds to proximal tubular epithelial cells (PTEC) and activates the complement system via the alternative pathway in vitro. Cellular ligands for properdin in the kidney have not yet been identified. Because properdin interacts with solid-phase heparin, we investigated whether heparan sulfate proteoglycans (HSPG) could be the physiological ligands of properdin. Kidneys from proteinuric rats showed colocalization of syndecan-1, a major epithelial HSPG, and properdin in the apical membranes of PTEC, which was not seen in control renal tissue. In vitro, PTEC did not constitutively express properdin. However, exogenous properdin binds to these cells in a dose-dependent fashion. Properdin binding was prevented by heparitinase pretreatment of the cells and was dose-dependently inhibited by exogenous heparin. ELISA and surface plasmon resonance spectroscopy (BIAcore) showed a strong dose-dependent interaction between heparan sulfate (HS) and properdin (K(d) = 128 nm). Pretreatment of HSPG with heparitinase abolished this interaction in ELISA. Competition assays, using a library of HS-like polysaccharides, showed that sulfation pattern, chain length, and backbone composition determine the interaction of properdin with glycosaminoglycans. Interestingly, two nonanticoagulant heparin derivatives inhibited properdin-HS interaction in ELISA and BIAcore. Incubation of PTEC with human serum as complement source led to complement activation and deposition of C3 on the cells. This C3 deposition is dependent on the binding of properdin to HS as shown by heparitinase pretreatment of the cells. Our data identify tubular HS as a novel docking platform for alternative pathway activation via properdin, which might play a role in proteinuric renal damage. Our study also suggests nonanticoagulant heparinoids may provide renoprotection in complement-dependent renal diseases.

Abstract: BACKGROUND: Accurate glomerular filtration rate (GFR) measurement in normal to high range is important for epidemiological studies and workup for kidney donation. Creatinine-based equations perform poorly in this GFR range. Creatinine clearance (CrCl) provides a substitute, provided urine is collected accurately and tubular creatinine handling can be accounted for. The latter is poorly characterized in the normal GFR range. METHODS: Therefore, we studied performance of CrCl, fractional creatinine excretion (FE(creat)) and its determinants in 226 potential kidney donors (47% males, mean 53 ± 10 years). GFR was assessed as (125)I-iothalamate clearance, simultaneously with 2-h CrCl and 24-h CrCl. RESULTS: Mean GFR was 101 ± 18, 2-h CrCl 110 ± 20 and 24-h CrCl 106 ± 29 mL/min/1.73 m(2). Mean bias of 24 h CrCl was 7.4 [inter-quartile range -6.7 to 20.0] mL/min/1.73 m(2), precision (R(2)) 0.39 and 30% accuracy 82%. Mean FE(creat) was 110 ± 11%. FE(creat) correlated with body mass index (BMI) (r = 0.34, P < 0.001). Consequently, bias of 24-h CrCl increased from 2.7 (inter-quartile range -6.5 to 16.7) to 8.6 (inter-quartile range -5.8 to 20.5) and 12.6 (inter-quartile range 7.0 to 25.4) mL/min in subjects with BMI <25, 25-30 and >30 kg/m(2), respectively (P < 0.05). On multivariate analysis, BMI and gender were predictors of FE(creat). CONCLUSIONS: CrCl systematically overestimates GFR in healthy subjects. The overestimation significantly correlates with BMI, with higher FE(creat) in subjects with higher BMI. The impact of BMI on tubular creatinine secretion can be accounted for, when using CrCl for GFR assessment in the normal to high range, by the following formula: GFR = 24-h CrCl - (22.75 + 0.76 � BMI - 0.29 � mean arterial pressure (-6.11 if female).

Abstract: Proteinuria is an established marker of decreased kidney function after kidney transplant. It recently has been suggested that albuminuria might be a more reliable marker. Although albuminuria often is regarded as a marker of glomerular damage, because chronic renal allograft damage is believed to be predominantly an interstitial process, albuminuria in this case might reflect tubular damage. Accordingly, we investigated the value of albuminuria, proteinuria, and tubular damage markers (KIM-1 [kidney injury molecule 1], NAG [N-acetyl-β-d-glucosaminidase], NGAL [neutrophil gelatinase-associated lipocalin], and H-FABP [heart fatty acid binding protein]) in predicting graft outcome in kidney transplant recipients.

Abstract: Nephrotic syndrome (NS) is a well-known risk factor for venous thromboembolism (VTE), however preventive measures are not routinely taken. In non-renal populations, statins are associated with lower risk of VTE. Hence, we set up this single-center retrospective cohort study to assess whether statin use influenced VTE risk in NS subjects.

Abstract: Renal function is the most important predictor of clinical outcome in heart failure (HF). It is therefore essential to have accurate and reliable measurement of renal function and early specific markers of renal impairment in patients with HF. Several renal functional entities exist, including glomerular filtration (GFR), glomerular permeability, tubulointerstitial damage, and endocrine function. Different markers have been studied that can be used to determine changes and the effect of treatment in these entities. In the present review, we summarize current and novel markers that give an assessment of renal function and prognosis in the setting of acute and chronic HF.

Abstract: The QRS interval, from the beginning of the Q wave to the end of the S wave on an electrocardiogram, reflects ventricular depolarization and conduction time and is a risk factor for mortality, sudden death and heart failure. We performed a genome-wide association meta-analysis in 40,407 individuals of European descent from 14 studies, with further genotyping in 7,170 additional Europeans, and we identified 22 loci associated with QRS duration (P < 5 � 10(-8)). These loci map in or near genes in pathways with established roles in ventricular conduction such as sodium channels, transcription factors and calcium-handling proteins, but also point to previously unidentified biologic processes, such as kinase inhibitors and genes related to tumorigenesis. We demonstrate that SCN10A, a candidate gene at the most significantly associated locus in this study, is expressed in the mouse ventricular conduction system, and treatment with a selective SCN10A blocker prolongs QRS duration. These findings extend our current knowledge of ventricular depolarization and conduction.

Abstract: Renin-angiotensin-aldosterone system blockade is a cornerstone in cardiovascular protection. Angiotensin-converting enzyme (ACE)-DD genotype has been associated with resistance to angiotensin-converting enzyme inhibition (ACEi), but data are conflicting. As sodium intake modifies the effect of ACEi as well as the genotype-phenotype relationship, we hypothesize gene-environment interaction between sodium-status, the response to ACEi, and ACE genotype.

Abstract: Before the introduction of renin-angiotensin-aldosterone system (RAAS) inhibitors in the 1980s, non-steroidal anti-inflammatory drugs (NSAIDs) were the only class of drugs available for the reduction of symptomatic proteinuria. Long-term data from those days suggested sustained renoprotective properties in proteinuric chronic kidney disease (CKD), but this potential has not been further explored, due to the adverse effects of NSAIDs, and due to the successful introduction of RAAS blockade for blood pressure control and renoprotection. The renoprotective potential of NSAIDs may seem surprising for the present generation of clinicians, as NSAIDs are well known for their adverse effects on the kidney. Interestingly, the newer selective COX-2 inhibitors (coxibs), such as non-selective (ns) NSAIDs, exert an antiproteinuric effect in CKD patients. This review discusses the role of NSAIDs as a class of drugs representing an old concept for renoprotection in the light of current insights on renoprotection. It has become increasingly clear during the last two decades, from evidence obtained almost exclusively in studies using RAAS blockade, that not only reduction of blood pressure, but also of proteinuria is a prerequisite for long-term renoprotection. Ns-NSAIDs and coxibs reduce proteinuria without reduction of blood pressure. Their possible role as an adjunct in individualised treatment strategies, particularly for individual patients resistant or intolerant to current therapy, will be discussed.

Abstract: Hypertension is a heritable and major contributor to the global burden of disease. The sum of rare and common genetic variants robustly identified so far explain only 1%-2% of the population variation in BP and hypertension. This suggests the existence of more undiscovered common variants. We conducted a genome-wide association study in 1,621 hypertensive cases and 1,699 controls and follow-up validation analyses in 19,845 cases and 16,541 controls using an extreme case-control design. We identified a locus on chromosome 16 in the 5' region of Uromodulin (UMOD; rs13333226, combined P value of 3.6 � 10�¹¹). The minor G allele is associated with a lower risk of hypertension (OR [95%CI]: 0.87 [0.84-0.91]), reduced urinary uromodulin excretion, better renal function; and each copy of the G allele is associated with a 7.7% reduction in risk of CVD events after adjusting for age, sex, BMI, and smoking status (H.R.�=�0.923, 95% CI 0.860-0.991; p�=�0.027). In a subset of 13,446 individuals with estimated glomerular filtration rate (eGFR) measurements, we show that rs13333226 is independently associated with hypertension (unadjusted for eGFR: 0.89 [0.83-0.96], p�=�0.004; after eGFR adjustment: 0.89 [0.83-0.96], p�=�0.003). In clinical functional studies, we also consistently show the minor G allele is associated with lower urinary uromodulin excretion. The exclusive expression of uromodulin in the thick portion of the ascending limb of Henle suggests a putative role of this variant in hypertension through an effect on sodium homeostasis. The newly discovered UMOD locus for hypertension has the potential to give new insights into the role of uromodulin in BP regulation and to identify novel drugable targets for reducing cardiovascular risk.

Abstract: Disease monitoring of autosomal dominant polycystic kidney disease (ADPKD) will become more important with potential upcoming therapeutic interventions. Because serum creatinine level is considered of limited use and measurement of effective renal blood flow (ERBF) and total renal volume are time consuming and expensive, there is a need for other biomarkers. We aimed to investigate which urinary markers have increased levels in patients with ADPKD; whether these urinary markers are associated with measured glomerular filtration rate (mGFR), ERBF, and total renal volume; and whether these associations are independent of albuminuria (urine albumin excretion [UAE]).

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Abstract: The urotensin system has been hypothesized to play an important role in the pathophysiology of diabetic nephropathy. In this multicenter, randomized, double-blind, placebo-controlled, 2-period crossover study, the effects of the urotensin receptor antagonist palosuran on urinary albumin excretion and blood pressure in hypertensive patients with type 2 diabetic nephropathy treated with a single blocker of the renin-angiotensin-aldosterone system were assessed. Patients with 24-hour albuminuria >0.5 and <3.0 g, systolic blood pressure >135 and <170 mm Hg, and/or diastolic blood pressure >85 and <110 mm Hg received both palosuran 125 mg BID and placebo for 4 weeks each. Fifty-four patients (20% women; mean age: 61.6 years, blood pressure: 155/84 mm Hg, and albuminuria: 1016 mg per 24 hours) were included in the per-protocol analysis. Palosuran did not affect albuminuria, blood pressure, glomerular filtration rate, or renal plasma flow significantly. These results question whether urotensin receptor antagonism represents a new treatment strategy in this high-risk patient population.

Abstract: The 5-5 homozygous CNDP1 (carnosinase) genotype is associated with a reduced risk of diabetic nephropathy. We investigated whether this association is sex specific and independent of susceptibility for type 2 diabetes.

Abstract: Renin-angiotensin-aldosterone system (RAAS) blockade improves prognosis in renal patients, but usually requires diuretic co-treatment. RAAS blockade can decrease erythropoietin (EPO) and/or haemoglobin (Hb) levels. Diuretics decrease EPO in rodents, but their effect on EPO and Hb in humans is unknown.

Abstract: Chronic low-grade inflammation is involved in late renal transplant dysfunction. Recent studies suggest a role for hemopexin, an acute phase protein, in kidney damage. We investigated whether hemopexin activity (Hx) predicts graft failure in renal transplant recipients (RTRs). In 557 RTRs with functioning grafts for >or=1 year, Hx was measured in citrate-plasma. RTRs were divided according to Hx into two groups; A: sextile 1-5 (464 RTRs, 83%) and B: sextile 6 (92 RTRs, 17%). Hx [median (IQR) 11.1 (3.3-19.1) arbitrary units] was measured at 6.0 (2.6-11.5) years post-transplant. RTRs with high Hx (group B) had significantly higher urinary protein excretion (UP) and diastolic blood pressure than group A, despite significantly more prevalent use of renin-angiotensin-aldosterone system inhibitors. After follow-up [4.6 (3.8-5.2) years], incidence of graft failure in group A was 25 (5%) and in group B 14 (15%,P = 0.0009) After adjustment for high-sensitivity C-reactive protein (hsCRP), UP and other potential confounders, Hx remained an independent predictor of graft failure [HR = 2.5 (95% CI 1.2-5.3), P = 0.01]. In conclusion, elevated Hx predicts late graft failure in RTRs, independent of hsCRP and UP. This suggests that Hx measurement, next to measurement of creatinine clearance and UP, could be of value for the identification of RTRs at risk for graft failure.

Abstract: Chronic transplant dysfunction explains the majority of late renal allograft loss and is accompanied by extensive tissue remodeling leading to transplant vasculopathy, glomerulosclerosis and interstitial fibrosis. Matrix proteoglycans mediate cell-cell and cell-matrix interactions and play key roles in tissue remodeling. The aim of this study was to characterize differential heparan sulfate proteoglycan and chondroitin sulfate proteoglycan expression in transplant vasculopathy, glomerulosclerosis and interstitial fibrosis in renal allografts with chronic transplant dysfunction.

Abstract: Cardiovascular disease (CVD) is a leading cause of mortality in renal transplant recipients (RTRs). Metabolic syndrome (MS) is highly prevalent in RTRs. Nonalcoholic fatty liver disease (NAFLD) is considered the hepatic component of MS. We investigated associations of NAFLD markers with MS and mortality. RTRs were investigated between 2001 and 2003. NAFLD markers, alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT) and alkaline phosphatase (AP) were measured. Bone and nonbone fractions of AP were also determined. Death was recorded until August 2007. Six hundred and two RTRs were studied (age 52+/-12 years, 55% men). At baseline 388 RTRs had MS. Prevalence of MS was positively associated with liver enzymes. During follow-up for 5.3[4.5-5.7] years, 95 recipients died (49 cardiovascular). In univariate Cox regression analyses, GGT (HR=1.43[1.21-1.69], p<0.001) and AP (HR=1.34[1.11-1.63], p=0.003) were associated with mortality, whereas ALT was not. Similar associations were found for cardiovascular mortality. Adjustment for potential confounders, including MS, diabetes and traditional risk factors did not materially change these associations. Results for nonbone AP mirrored that for total AP. ALT, GGT and AP are associated with MS. Of these three enzymes, GGT and AP are associated with mortality, independent of MS. These findings suggest that GGT and AP are independently related to mortality in RTRs.

Abstract: Cholesteryl ester transfer protein (CETP) inhibitors raise high-density lipoprotein (HDL) cholesterol, but torcetrapib, the first-in-class inhibitor tested in a large outcome trial, caused an unexpected blood pressure elevation and increased cardiovascular events. Whether the hypertensive effect resulted from CETP inhibition or an off-target action of torcetrapib has been debated. We hypothesized that common single-nucleotide polymorphisms in the CETP gene could help distinguish mechanism-based from off-target actions of CETP inhibitors to inform on the validity of CETP as a therapeutic target.

Abstract: Renin-angiotensin-aldosterone system (RAAS) blockade improves outcome in cardiovascular disease (CVD) and chronic kidney disease (CKD), but the residual risk during monotherapy RAAS blockade remains very high. This review discusses the place of dual RAAS blockade in improving these outcomes.

Abstract: We conducted genome-wide association analyses of mean leukocyte telomere length in 2,917 individuals, with follow-up replication in 9,492 individuals. We identified an association with telomere length on 3q26 (rs12696304, combined P = 3.72 x 10(-14)) at a locus that includes TERC, which encodes the telomerase RNA component. Each copy of the minor allele of rs12696304 was associated with an approximately 75-base-pair reduction in mean telomere length, equivalent to approximately 3.6 years of age-related telomere-length attrition.

Abstract: Using genome-wide association, we identify common variants at 2p12-p13, 6q26, 17q23 and 19q13 associated with serum creatinine, a marker of kidney function (P = 10(-10) to 10(-15)). Of these, rs10206899 (near NAT8, 2p12-p13) and rs4805834 (near SLC7A9, 19q13) were also associated with chronic kidney disease (P = 5.0 x 10(-5) and P = 3.6 x 10(-4), respectively). Our findings provide insight into metabolic, solute and drug-transport pathways underlying susceptibility to chronic kidney disease.

Abstract: Potential therapeutic interventions are being developed for autosomal dominant polycystic kidney disease (ADPKD). A pivotal question will be when to initiate such treatment, and monitoring disease progression will thus become more important. Therefore, the prevalence of renal abnormalities in ADPKD at different ages was evaluated.

Abstract: The Modification of Diet in Renal Disease (MDRD) study equation and the Cockcroft-Gault (CG) equation perform poorly in the (near-) normal range of GFR. Whether this is due to the level of GFR as such or to differences in individual characteristics between healthy individuals and patient with chronic kidney disease (CKD) is unknown.

Abstract: The prognostic impact of reduced glomerular filtration rate (GFR) in chronic heart failure (CHF) is increasingly recognised, but little is known about tubular damage in these patients.

Abstract: BACKGROUND AND AIMS: We aimed to determine the effect of short-term dietary sodium restriction on plasma total cholesterol, LDL-C, HDL-C, triglycerides, apolipoprotein (apo) A-I, apo B and high molecular weight (HMW) adiponectin in non-obese, normotensive young men. Glomerular filtration rate (GFR), effective renal plasma flow (ERPF), plasma renin activity (PRA) and aldosterone were also measured. METHODS AND RESULTS: Sixty-five men, aged 23 +/- 7 years, were randomly studied on a high sodium intake (HS, 228 +/- 77 mmol Na+/24 h) and a low sodium intake (LS, 36 +/- 27 mmol Na+/24 h), each period lasting 1 week. LS decreased GFR and ERPF and increased PRA and aldosterone (p < 0.0001 for all). LS also induced a decrease in HDL-C (3.8 +/- 10.8%), apo A-I (3.7 +/- 6.5%) and HMW-adiponectin (13.6 +/- 40.5%) (p < 0.05 for all), but plasma total cholesterol, LDL-C, triglycerides and apo B did not significantly change. The changes in HDL-C and apo A-I were correlated negatively to the changes in effective renal plasma flow (p < 0.05), whereas the changes in HMW adiponectin were correlated negatively to the changes in PRA and aldosterone (p < 0.05 for both). CONCLUSION: Short term sodium restriction modestly decreases HDL-C, apo A-I and HMW-adiponectin in healthy men. Changes in GFR and ERPF and in the renin-angiotensin-aldosterone system as induced by LS may be involved in these responses.

Abstract: To investigate the relationship between signs and symptoms of congestion, renal impairment and outcome in chronic heart failure (CHF) patients.

Abstract: S100B is a prominent cell damage marker which can lead to sustained pro-inflammatory signaling. The aim was to investigate cross-sectional associations of steady-state S100B concentrations, particularly with C-reactive protein (CRP), in renal transplant recipients (RTRs) and also to investigate prospectively whether S100B would predict graft failure or mortality.

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Abstract: The (CTG)(n) polymorphism in the serum carnosinase (CN-1) gene affects CN-1 secretion. Since CN-1 is heavily glycosylated and glycosylation might influence protein secretion as well, we tested the role of N-glycosylation for CN-1 secretion and enzyme activity. We also tested whether CN-1 secretion is changed under hyperglycemic conditions.

Abstract: Procalcitonin, a well-known biomarker of sepsis and bacterial infections, is produced by adipose tissue and has potential as a marker for chronic low-grade inflammation.

Abstract: Elevated blood pressure (BP), which is a major risk factor for cardiovascular disease, is highly prevalent worldwide. Recently, interest has grown in the role of dietary protein in human BP. We performed a systematic review of all published scientific literature on dietary protein, including protein from various sources, in relation to human BP.

Abstract: Uric acid (UA) is the final catabolic product of purine metabolism and elevated levels are associated with diabetes and cardiovascular disease. A recent meta-analysis of genome-wide association studies totalling 28,141 participants identified five novel loci associated with serum UA levels. In our population-based cohort of 7795 subjects, we replicated four of these five loci; PDZK1 (rs12129861, P = 1.07 x 10(-3)), glucokinase regulator protein (GCKR) (rs780094, P = 4.83 x 10(-4)), SLC16A9 (rs742132, P = 0.047) and SLC22A11 (rs17300741, P = 6.13 x 10(-3)), but not LRRC16A (rs742132, P = 0.645). Serum UA concentration is a complex trait, closely associated to renal UA handling (fractional UA excretion, P < 1 x 10(-300)), renal function (serum creatinine, P < 1 x 10(-300)) and the metabolic syndrome (including fasting insulin, P = 2.48 x 10(-232); insulin resistance, P = 2.51 x 10(-258); waist circumference, P < 1 x 10(-300)) and systolic blood pressure (P = 1.93 x 10(-219)). Together these factors explain 67% of the variance in UA levels. Therefore, we sought to determine the potential contribution of these factors to the association of these novel loci with UA levels, by including them as additional explanatory variables in our analyses, and by considering them as alternative response variables. The association with the GCKR locus is attenuated by serum triglycerides and fractional UA excretion. We also observed the GCKR locus to be associated with total cholesterol (P = 7.52 x 10(-6)), triglycerides (P = 2.65 x 10(-9)), fasting glucose (P = 0.011), fractional UA excretion (P = 3.36 x 10(-5)) and high-sensitive CRP (P = 1.18 x 10(-3)) also after adjusting for serum UA levels. We argue that GCKR locus affects serum UA levels through a factor that also affects triglycerides.

Abstract: Homozygosity for a five leucine repeat (5L-5L) in the carnosinase gene (CNDP1) has been found to be cross-sectionally associated with a low frequency of diabetic nephropathy (DN), mainly in type 2 diabetes. We prospectively investigated in patients with type 1 diabetes whether: (1) 5L-5L is associated with mortality; (2) there is an interaction of 5L-5L with DN or sex for prediction of mortality; and (3) 5L-5L is associated with progression to end-stage renal disease (ESRD).

Abstract: C-C chemokine receptor 5 (CCR5) plays an important role in inflammation. A 32 base-pair (�32) deletion in the CCR5 gene leads to a nonfunctional receptor. This deletion has been reported to have a protective effect on the development and progression of several autoimmune diseases. We investigated whether the �32 deletion is associated with disease susceptibility in a population of patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and lupus nephritis (LN); and whether it is associated with disease severity.

Abstract: Differential renal expression of a homolog of the angiotensin-converting enzyme (ACE), that is, ACE2, has been implicated as a genetic basis of polygenetic hypertension in the stroke-prone spontaneously hypertensive rat model. However, data on the role of ACE2 in hypertension are still inconclusive. Therefore, we analyzed kidney ACE2 mRNA, ACE2 protein and ACE2 enzyme activities in the adult polygenetic stroke-prone spontaneously hypertensive rat (SHRSP) and the monogenetic TGR(mREN2)27 rat models, in comparison with their normotensive reference strains, Wistar-Kyoto (WKY) and Spraque-Dawley (SD) rats, respectively. Kidney ACE2 mRNA was studied using quantitative real-time reverse transcriptase-PCR (RT-PCR) in cortex and medulla, whereas protein expression was scored semiquantitatively in detail in different renal structures using immunohistochemistry. Furthermore, total renal tissue ACE2 activity was measured using a fluorimetric assay that was specified by the ACE2 inhibitor DX600. In SHRSP and homozygous TGR(mREN2)27 rats with established hypertension, kidney ACE2 mRNA, protein and tissue ACE2 activities were not different from their respective WKY and SD reference strain, respectively. In addition, when we looked at renal localization, we found ACE2 protein to be predominantly present in glomeruli and endothelium with weak staining in distal and negative staining in proximal tubuli. Thus, our data challenge previous work that implicates ACE2 as a candidate gene for hypertension in SHRSP by reporting a significant reduction of ACE2 in the kidneys of SHRSP. Taken together, renal ACE2 is not altered in the SHRSP and TGR(mREN2)27 genetic rat models with established hypertension.

Abstract: The Modification of Diet in Renal Disease (MDRD) Study equation underestimates measured glomerular filtration rate (GFR) at levels>60 mL/min/1.73 m2, with variable accuracy among subgroups; consequently, estimated GFR (eGFR)>or=60 mL/min/1.73 m2 is not reported by clinical laboratories. Here, performance of a more accurate GFR-estimating equation, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, is reported by level of GFR and clinical characteristics.

Abstract: The pathogenesis of diabetes mellitus (DM) is variable, comprising different inflammatory and immune responses. Proteome analysis holds the promise of delivering insight into the pathophysiological changes associated with diabetes. Recently, we identified and validated urinary proteomics biomarkers for diabetes. Based on these initial findings, we aimed to further validate urinary proteomics biomarkers specific for diabetes in general, and particularity associated with either type 1 (T1D) or type 2 diabetes (T2D).

Abstract: Urine proteome analysis is rapidly emerging as a tool for diagnosis and prognosis in disease states. For diagnosis of diabetic nephropathy (DN), urinary proteome analysis was successfully applied in a pilot study. The validity of the previously established proteomic biomarkers with respect to the diagnostic and prognostic potential was assessed on a separate set of patients recruited at three different European centers. In this case-control study of 148 Caucasian patients with diabetes mellitus type 2 and duration �5 years, cases of DN were defined as albuminuria >300 mg/d and diabetic retinopathy (n = 66). Controls were matched for gender and diabetes duration (n = 82).

Abstract: To investigate the effect of benfotiamine on urinary albumin excretion (UAE) and the tubular damage marker kidney injury molecule-1 (KIM-1) in patients with type 2 diabetes and nephropathy.

Abstract: Chronic inflammation is a major outcome determinant in several renal disorders. Induction of monocyte chemoattractant protein (MCP)-1 expression in tubular epithelial cells contributes importantly to the recruitment of inflammatory cells from the circulation toward the damaged tubulo-interstitium. Because the MCP-1 gene contains several c-Jun binding sites, we hypothesized that the c-Jun NH(2)-terminal kinase (JNK) pathway regulates MCP-1 expression and subsequently tubulo-interstitial inflammation. This was investigated in cultured rat tubular epithelial cells (NRK-52E) and in the rat unilateral ischemia/reperfusion (I/R) model. In NRK-52E cells, the JNK inhibitor anthra(1,9-cd)pyrazol-6(2H)-one-1,9-pyrazoloanthrone (SP600125) reduced interleukin-1beta-, transforming growth factor-beta-, or bovine serum albumin-induced MCP-1 expression in a potent manner (up to 150-fold). In the rat I/R model, JNK activation was low in controls but induced in tubular cells from 30 min after I/R. The extent of JNK activation correlated with interstitial macrophage accumulation. Treatment with SP600125 (30 mg/kg/day i.p. for 4 days) reduced renal c-Jun activation; MCP-1, osteopontin, and vimentin expression; and interstitial macrophage and T-cell accumulation (all p < 0.05). In human renal disease, we also found induction of JNK activation, which correlated strongly with interstitial macrophage accumulation, tubulointerstitial fibrosis, and renal function loss. In conclusion, these data indicate that the JNK pathway plays an important role in renal inflammation, at least in part through induction of MCP-1 gene expression in tubular epithelial cells.

Abstract: To test whether the genetic variant CCR5Delta32 in the CC-chemokine receptor 5, which is known to lead to CCR5 deficiency, is associated with mortality in type 2 diabetes patients.

Abstract: Renal failure is a major complication in glycogen storage disease type I (GSD I). We studied the natural course of renal function in GSD I patients. We studied differences between patients in optimal and nonoptimal metabolic control and possible renoprotective effects of angiotensin converting enzyme inhibition.

Abstract: Vitamin D is typically viewed as a key player in the regulation of calcium and phosphate levels and the control of bone metabolism; however, growing evidence suggests that vitamin D deficiency may also have an important role in the progressive loss of renal function. Vitamin D deficiency is particularly frequent in patients with chronic kidney disease, in whom it is associated with increased mortality. Studies indicate that treatment with vitamin D analogues reduces proteinuria, suppresses the renin-angiotensin-aldosterone system (RAAS), and exerts anti-inflammatory and immunomodulatory effects. These pleiotropic effects render vitamin D a potentially interesting treatment modality for renoprotection in patients with chronic kidney disease. Whether vitamin D has clinically relevant renoprotective effects in addition to RAAS blockade is currently under investigation.

Abstract: Chronic transplant dysfunction is the leading cause of long-term renal allograft loss. One of the histologic hallmarks of chronic transplant dysfunction is transplant vasculopathy characterized by accumulation of smooth muscle cells (SMCs) in the arterial subendothelial space, leading to ischemic graft failure. Currently, no therapy is available for transplant vasculopathy, and knowledge of the origin (donor vs. recipient) of neointimal cells may contribute to develop adequate strategies.

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Abstract: In humans, the insertion/deletion polymorphism in the angiotensin converting enzyme (ACE) gene accounts for half of the variance in plasma ACE activity. The deletion allele is associated with high plasma ACE activity, cardiovascular disease, and renal disease. In rat, a similar association is found between the B and L alleles of a microsatellite marker in the ACE gene. We identified the B/L variation in the Wistar outbred rat and bred two lines homozygous for the two alleles (WU-B and WU-L). ACE activity was measured in serum, heart, kidney, and aorta homogenates. Immunohistochemistry and ACE mRNA expression were performed in heart, kidney, and aortic tissue. Aortic rings were collected and stimulated with AngI, AngII, and AngI with Lisinopril to measure ACE functional activity by vasoconstrictor response. Serum, heart, and kidney ACE activity and kidney mRNA expression were two-fold higher in WU-B. Kidney staining showed a clear difference in tubular ACE expression, with more staining in WU-B. While in aorta ACE activity and mRNA expression was twofold higher in WU-L, functional conversion of AngI was higher in WU-B, indicating either a functional difference in AngI to AngII conversion between the two alleles due to different splicing or the presence of other factors involved in the conversion that are differentially expressed as the result of differences in the ACE alleles. The newly developed WU-B and WU-L lines show tissue-specific differences in ACE expression and activity. This provides an experimental tool to study the pathophysiologic consequences of differences in ACE alleles in renal and cardiovascular disease.

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Abstract: Chronic transplant dysfunction (CTD) is the leading cause for limited kidney graft survival. Renal CTD is characterized by interstitial and vascular remodeling leading to interstitial fibrosis, tubular atrophy and transplant vasculopathy (TV). The origin of cells and pathogenesis of interstitial and vascular remodeling are still unknown. To study graft-versus-recipient origin of interstitial myofibroblasts, vascular smooth muscle cells (SMCs) and endothelial cells (ECs), we here describe a new rat model for renal CTD using Dark Agouti kidney donors and R26 human placental alkaline phosphatase transgenic Fischer344 recipients. This model showed the development of CTD within 12 weeks after transplantation. In interstitial remodeling, both graft- and recipient-derived cells contributed to a similar extent to the accumulation of myofibroblasts. In arteries with TV, we observed graft origin of neointimal SMCs and ECs, whereas in peritubular and glomerular capillaries, we detected recipient EC chimerism. These data indicate that, within the interstitial and vascular compartments of the transplanted kidney, myofibroblasts, SMCs and ECs involved in chronic remodeling are derived from different sources and suggest distinct pathogenetic mechanisms within the renal compartments.

Abstract: A high sodium (HS) intake is associated to increased cardiovascular and renal risk, especially in overweight subjects. We hypothesized that abnormal sodium and fluid handling is involved, independent of hypertension or insulin resistance. Therefore, we studied the relation between BMI and sodium-induced changes in extracellular fluid volume (ECFV; distribution volume of (125)I-iothalamate) in 78 healthy men, not selected for BMI. A total of 78 subjects with a median BMI of 22.5 (range: 19.2-33.9 kg/m(2)) were studied after 1 week on a low sodium (LS) diet (50 mmol Na(+)/d) and after 1 week on HS (200 mmol Na(+)/d). The change from LS to HS resulted in an increase in ECFV of 1.2 +/- 1.8 l. Individual changes in ECFV were correlated to BMI (r = 0.361, P < 0.01). Furthermore, in response to HS, a higher BMI was associated to a higher rise in filtered load of sodium (FL(Na(+)) = [Na(+)] x GFR, r = 0.281, P < 0.05). Thus, a shift to HS leads to a larger rise in ECFV in healthy subjects with higher BMI, associated with an elevated FL(Na(+)) during HS. Although no hypertension occurred in these healthy subjects, our data provide a potential explanation for the interaction of sodium intake and BMI on cardiovascular and renal risk. Exaggerated fluid retention may be an early pathogenic factor in the cardiorenal complications of overweight.

Abstract: Dyslipidemia contributes to increased cardiovascular risk in nephrotic syndrome. We questioned whether reduction in proteinuria not only lowers low-density lipoprotein cholesterol (LDL-C), but also high-density lipoprotein cholesterol (HDL-C) and cholesteryl ester transfer protein (CETP) mass and whether changes in HDL-C were related to changes in plasma adiponectin.

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Abstract: To evaluate the role of restricting dietary sodium intake in chronic kidney disease (CKD) and its complications.

Abstract: End-stage renal disease is associated with high health-care costs and low quality of life compared with chronic kidney disease. The renoprotective effectiveness of angiotensin-converting enzyme inhibitors (ACEi) is largely determined by the ACE insertion/deletion (I/D) polymorphism. We determined the cost-effectiveness of ACEi therapy in nondiabetic nephropathy for the ACE II/ID and for the ACE DD genotype separately. Furthermore, we considered a selective screen-and-treat strategy in which patients are prescribed alternative, more effective, therapy based on their ACE (I/D) polymorphism.

Abstract: Ischemia/reperfusion injury (IRI) is a risk factor for the development of interstitial fibrosis. Previously we had shown that after renal IRI, bone marrow-derived cells (BMDC) can differentiate to interstitial myofibroblasts. Here we hypothesized that the immunosuppressant ciclosporin A (CsA), known for its profibrotic side effect, promotes myofibroblast differentiation of BMDC in the postischemic kidney.

Abstract: Tubulointerstitial lesions are important in the progression of proteinuric renal disease. Tubular kidney injury molecule-1 (Kim-1) is induced in acute renal injury and reversible as a natural course. Kim-1 is also present in chronic renal damage; however, the dynamics of Kim-1 in chronic renal damage and effects of antiproteinuric treatment on Kim-1 are unknown. We studied Kim-1 in adriamycin nephrosis (AN) before and after renin-angiotensin system blockade. A renal biopsy was taken 6 wk after adriamycin injection to study renal damage and Kim-1 expression. Subsequently, ACE inhibition (ACEi; n = 23), angiotensin II antagonist (AT(1A); n = 23), or vehicle (n = 10) was given for 6 wk; healthy rats served as controls (CON; n = 8). In AN, renal Kim-1 mRNA was induced 26-fold vs. CON at week 6, with further increase in vehicle to week 12 (40-fold) but was reduced by ACEi and AT(1A) to 10- and 12-fold vs. CON (P < 0.05 vs. week 6). Kim-1 protein was undetectable in CON; in AN, it was present in brush border of dilated tubules in areas with adjacent interstitial lesions. Renal Kim-1 protein levels increased from weeks 6-12 in vehicle and decreased in ACEi- and AT(1A)-treated groups (P < 0.05). In vehicle, urinary Kim-1 was increased (P < 0.05 vs. CON), with a reduction by ACEi and AT(1A) (P < 0.05 vs. vehicle). Renal and urinary Kim-1 correlated with proteinuria and interstitial damage cross-sectionally. Reductions in proteinuria and renal Kim-1 correlated, which was not associated by corresponding changes in tubulointerstitial fibrosis. In conclusion, on longitudinal follow-up during antiproteinuric treatment increased renal Kim-1 expression is reversible in proportion to proteinuria reduction, likely reflecting reversibility of early tubular injury, supporting its potential as a biomarker for tubulointerstitial processes of damage and repair.

Abstract: Chronic transplant dysfunction (CTD) is the leading cause of long-term renal allograft loss and is characterized by specific histological lesions including transplant vasculopathy, interstitial fibrosis, and focal glomerulosclerosis. Increasing evidence indicates that aldosterone is a direct mediator of renal damage via the mineralocorticoid receptor (MR). The MR antagonist spironolactone is renoprotective in native chronic kidney disease, but its effects on CTD are unknown. We studied the effects of spironolactone treatment on CTD development in the Dark Agouti-to-Wistar-Furth renal allograft transplant model, by treatment with 20 mg/kg spironolactone or vehicle daily by oral gavage from 2 days before transplantation (donors and recipients) throughout the experiment (12 wk, recipients). Dark Agouti-to-Dark Agouti isografts served as negative controls. Spironolactone significantly ameliorated the development of transplant vasculopathy in allografts by reducing the number of affected intrarenal arteries. In addition, spironolactone treatment showed a trend toward reduced proteinuria and focal glomerulosclerosis, and significantly reduced glomerular macrophage influx. However, spironolactone treatment did not affect interstitial fibrosis, interstitial macrophage influx, creatinine clearance, and systolic blood pressure. We conclude that spironolactone selectively ameliorates transplant vasculopathy and glomerular lesions in renal CTD in rats. These results suggest that spironolactone may have renoprotective potential as an adjunct treatment in renal transplantation to ameliorate CTD.

Abstract: The CC-chemokine receptor 5 (CCR5) is a receptor for various proinflammatory chemokines, and a deletion variant of the CCR5 gene (CCR5 Delta 32) leads to deficiency of the receptor. We hypothesized that CCR5 Delta 32 modulates inflammation-driven mortality in patients with ESRD. We studied the interaction between CCR5 genotype and levels of high-sensitivity C-reactive protein (hsCRP) in 603 incident dialysis patients from the multicenter, prospective NEtherlands COoperative Study on the Adequacy of Dialysis (NECOSAD) cohort. CCR5 genotype and hsCRP levels were both available for 413 patients. During 5 yr of follow-up, 170 patients died; 87 from cardiovascular causes. Compared with the reference group of patients who had the wild-type CCR5 genotype and hsCRP <or= 10 mg/L (n = 225), those carrying the deletion allele with hsCRP <or= 10 mg/L (n = 55) had similar mortality, and those carrying the wild-type genotype with hsCRP > 10 mg/L (n = 108) had an increased risk for mortality (HR: 1.82; 95% CI: 1.29 to 2.58). However, those carrying the deletion allele with hsCRP > 10 mg/L (n = 25) had a mortality rate similar to the reference group; this seemingly protective effect of the CCR5 deletion was even more pronounced for cardiovascular mortality. We replicated these findings in an independent Swedish cohort of 302 ESRD patients. In conclusion, the CCR5 Delta 32 polymorphism attenuates the adverse effects of inflammation on overall and cardiovascular mortality in ESRD.

Abstract: We sought to investigate the relationship between increased central venous pressure (CVP), renal function, and mortality in a broad spectrum of cardiovascular patients.

Abstract: Diuretics, when added to angiotensin-converting enzyme inhibitors (ACE inhibitors) treatment, can augment the response to ACE inhibitors, but may have adverse effects on renal function, which negatively affect prognosis. While in heart failure rats combined therapy initially improved cardiac function and prognosis, this benefit was completely lost at later stages. We now studied renal effects of adding hydrochlorothiazide to ACE inhibitor after myocardial infarction in rats. Rats were randomized to ACE inhibitor quinapril monotherapy or quinapril with add-on hydrochlorothiazide. Survival was monitored for 14 months. Plasma creatinine, measured at 4 months, was increased by 40% in quinapril with add-on hydrochlorothiazide compared to quinapril. Although overall 14-months mortality was similar in quinapril with add-on hydrochlorothiazide and quinapril, stratification based on plasma creatinine showed increased mortality in the tertile with highest plasma creatinine (P=0.03, Log rank). With add-on hydrochlorotiazide, renal morphology displayed severe renal interstitial lesions; tubular dilatation and fibrosis. Interstitial myofibroblast transformation (alpha-smooth muscle actine staining) was increased at 8 and 14 months, and coincided with collagen deposition and interstitial inflammation (macrophage influx). In rats with quinapril monotherapy or untreated rats, renal structure was normal. Thus, adding hydrochlorotiazide to ACE inhibitor detrimentally affected not only renal function, but also renal structure in rats with myocardial infarction. Altered pharmacokinetics, resulting from a vicious circle of reduced renal function and increased circulating drug levels, may provide an explanation for the adverse renal effects and may exert unfavorable effects on long-term prognosis after myocardial infarction.

Abstract: Tubulointerstitial damage plays an important role in chronic kidney disease (CKD) with proteinuria. Urinary kidney injury molecule 1 (KIM-1) reflects tubular KIM-1 and is considered a sensitive biomarker for early tubular damage. We hypothesized that a decrease in proteinuria by using therapeutic interventions is associated with decreased urinary KIM-1 levels.

Abstract: Reduced glomerular filtration rate (GFR) is strongly associated with reduced survival in patients with chronic heart failure (CHF). Our aim was to determine different pathophysiologic markers that are associated with reduced renal function in CHF.

Abstract: Renoprotection is predicted by the antiproteinuric efficacy of a pharmacological agent. Non-steroidal anti-inflammatory drugs (NSAIDs) interfering non-selectively in the prostaglandin system have strong antiproteinuric potency without reduction of systemic blood pressure. The effect of the selective COX-2 inhibitor rofecoxib in proteinuric patients is unknown, granted recently reported detrimental effects in non-renal patients. Short-term effects of rofecoxib on proteinuria and blood pressure as compared to NSAID and RAAS blockade were studied.

Abstract: Both preoperative left ventricular dysfunction and postoperative renal function deterioration are associated with increased long-term mortality after cardiac surgery. The influence of preoperative left ventricular dysfunction on postoperative renal dysfunction and long-term mortality is not defined.

Abstract: During normal pregnancy, in contrast to preeclampsia, plasma hemopexin activity is increased together with a decreased vascular angiotensin II receptor (AT(1)) expression. We now tested the hypothesis that hemopexin can downregulate the AT(1) receptor in vitro. Analysis of human monocytes or endothelial cells by flow cytometry showed decreased membrane density of AT(1) exclusively after incubation with active hemopexin, whereas in supernatants of these cell cultures, AT(1) molecules could be detected (dot blotting). Also, diminished AT(1) was observed in endothelial cell lysates after contact with hemopexin (Western blotting). Hemopexin also induced extracellular signal-regulated kinase 1/2 pathway inhibition in cells after stimulation with angiotensin II in vitro, indicating downregulation of AT(1) by hemopexin. In addition, functional loss of AT(1) occurred after incubation of rat aortic rings with active hemopexin, as reflected by decreased contraction of the aortic rings on stimulation with angiotensin II. It was further demonstrated that plasma from normal pregnant women decreased the AT(1) receptor expression on monocytes as compared with plasma from nonpregnant women or preeclamptic women. Finally, it was shown that plasma hemopexin activity increases during normal gestation from week 10 onward. We concluded that active hemopexin is able to downregulate the AT(1) receptor in human monocytes, endothelial cells, and rat aortic rings. We propose that the physiological role of enhanced hemopexin activity during healthy pregnancy is to downregulate the vascular AT(1) receptor, promoting an expanded vascular bed. Inhibition of hemopexin activity during preeclampsia may result in an enhanced AT(1) receptor expression and a contracted vascular bed.

Abstract: Urinary excretion is currently regarded as the main mechanism of elimination of N-terminal prohormone brain natriuretic peptide (NT-proBNP). The clinical implications and the value of measurement of urinary NT-proBNP in patients with heart failure are largely unknown.

Abstract: Chronic low-grade inflammation is involved in chronic transplant dysfunction after renal transplantation. Procalcitonin (PCT), known to reflect microbial inflammation, may also reflect ongoing noninfectious chronic low-grade inflammation in organ parenchyma, including transplanted kidneys. We aimed to compare predictive performance of plasma PCT for development of graft failure in renal transplant recipients (RTR) with that of high-sensitivity C-reactive protein (hsCRP), an established marker of systemic chronic low-grade inflammation.

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Abstract: The effect of worsening renal function (WRF) after discharge on outcome in patients with heart failure is unknown.

Abstract: Mortality rates are higher in renal transplant recipients (RTR) than in the general population (GP). It is unknown what risk factors account for this difference.

Abstract: Elevated blood pressure is a common, heritable cause of cardiovascular disease worldwide. To date, identification of common genetic variants influencing blood pressure has proven challenging. We tested 2.5 million genotyped and imputed SNPs for association with systolic and diastolic blood pressure in 34,433 subjects of European ancestry from the Global BPgen consortium and followed up findings with direct genotyping (N � 71,225 European ancestry, N � 12,889 Indian Asian ancestry) and in silico comparison (CHARGE consortium, N = 29,136). We identified association between systolic or diastolic blood pressure and common variants in eight regions near the CYP17A1 (P = 7 � 10(-24)), CYP1A2 (P = 1 � 10(-23)), FGF5 (P = 1 � 10(-21)), SH2B3 (P = 3 � 10(-18)), MTHFR (P = 2 � 10(-13)), c10orf107 (P = 1 � 10(-9)), ZNF652 (P = 5 � 10(-9)) and PLCD3 (P = 1 � 10(-8)) genes. All variants associated with continuous blood pressure were associated with dichotomous hypertension. These associations between common variants and blood pressure and hypertension offer mechanistic insights into the regulation of blood pressure and may point to novel targets for interventions to prevent cardiovascular disease.

Abstract: Microalbuminuria (albuminuria 30-300 mg per 24-hour urine collection) is a well-known risk marker for arterial thromboembolism. It is assumed that microalbuminuria reflects generalized endothelial dysfunction. Hence, microalbuminuria may also predispose for venous thromboembolism (VTE).

Abstract: Proteinuria-associated endothelial dysfunction (ED) is assumed to play a main role in the cardiovascular morbidity in proteinuric patients. However, the connection between proteinuria and systemic endothelial function is not clear yet. Therefore, we studied aortic endothelial function in Munich Wistar Fromter (MWF) and fawn-hooded hypertensive (FHH) inbred rat strains with genetic proteinuria to determine the specific impact of proteinuria on the development of ED.

Abstract: Inhibition of the renin-angiotensin-aldosterone system (RAAS) provides renoprotection in adriamycin nephropathy (AN), along with a decrease in overexpression of glomerular heparanase. Angiotensin II (AngII) and reactive oxygen species (ROS) are known to regulate heparanase expression in vivo. However, it is unknown whether this is also the case for aldosterone. Therefore, we further assessed the role of aldosterone, AngII and ROS in the regulation of glomerular heparanase expression.

Abstract: Several findings link systemic lupus erythematosus (SLE) with C1q, the first molecule of the classical complement pathway. Polymorphisms of the C1qA gene are associated with low serum C1q levels in patients with cutaneous LE, but C1q polymorphisms have not been studied in patients with systemic lupus.

Abstract: Cardiovascular and connective tissue disorders are very common in patients with end-stage renal disease (ESRD), and the accumulation of advanced glycation end products (AGEs) is significantly increased in these patients. Accumulation of AGEs is believed to have a role in tissue protein aging and the pathogenesis of such age-related diseases as diabetes and ESRD. AGEs accumulate in patients with ESRD as a result of nonenzymatic glycation, oxidative stress, and diminished clearance of AGE precursors. Some AGEs show characteristic brown pigmentation and fluorescence, form protein-protein cross-links, and may ligate with AGE-specific receptors, inducing oxidative stress and cytokine production. This review focuses on the clinical relevance of AGE accumulation in patients with ESRD treated by dialysis for the development of long-term complications. The formation and accumulation of AGEs in patients with ESRD are discussed, as well as the relationship between AGE accumulation and such major complications of ESRD as cardiovascular and connective tissue disorders.

Abstract: Insulin resistance has been implicated to underlie both excess cardiovascular disease and chronic transplant dysfunction after renal transplantation. Skeletal muscle mainly determines peripheral insulin resistance, and could therefore affect outcome.

Abstract: The feasibility, validity, and possible applications of the assessment of extracellular fluid volume (ECFV) simultaneous with glomerular filtration rate (GFR) were assessed in a series of validation studies using the constant infusion method of (125)I-iothalamate (IOT). In 48 subjects with a broad range of GFR, distribution volume (V(d)) of IOT corresponded well with V(d) bromide (16.71 +/- 3.0 and 16.73 +/- 3.2 l, respectively, not significant), with a strong correlation (r = 0.933, P < 0.01) and without systematic deviations. Reproducibility assessment in 25 healthy male subjects showed coefficients of variation of 8.6% of duplicate measurement of V(d) IOT during strictly standardized (50 mmol Na(+)/d) sodium intake. An increase in dietary sodium intake (200 mmol Na(+)/d) induced a corresponding rise in V(d) IOT of 1.11 +/- 1.5 l (P < 0.01). In 158 healthy prospective kidney donors, the impact of indexing of GFR to ECFV was analyzed. Age, gender, height, and body surface area (BSA) were determinants of GFR. Whereas GFR, GFR/BSA, and GFR/height were gender-dependent, GFR/ECFV was gender-independent and not related to height or BSA. This supports the potential of normalizing GFR by ECFV. Thus, ECFV can be simultaneously assessed with GFR by the constant infusion method using IOT. After appropriate validation, also other GFR tracers could be used for such a simultaneous estimation, providing a valuable resource of data on ECFV in renal studies and, moreover, allowing GFR to be indexed to the body fluid compartment it clears: the ECFV.

Abstract: The fields of pharmacogenetics and pharmacogenomics have become important practical tools to progress goals in medical and pharmaceutical research and development. As more screening tests are being developed, with some already used in clinical practice, consideration of cost-effectiveness implications is important. A systematic review was performed on the content of and adherence to pharmacoeconomic guidelines of recent pharmacoeconomic analyses performed in the field of pharmacogenetics and pharmacogenomics. Economic analyses of screening strategies for genetic variations, which were evidence-based and assumed to be associated with drug efficacy or safety, were included in the review. The 20 papers included cover a variety of healthcare issues, including screening tests on several cytochrome P450 (CYP) enzyme genes, thiopurine S-methyltransferase (TMPT) and angiotensin-converting enzyme (ACE) insertion deletion (ACE I/D) polymorphisms. Most economic analyses reported that genetic screening was cost effective and often even clearly dominated existing non-screening strategies. However, we found a lack of standardization regarding aspects such as the perspective of the analysis, factors included in the sensitivity analysis and the applied discount rates. In particular, an important limitation of several studies related to the failure to provide a sufficient evidence-based rationale for an association between genotype and phenotype. Future economic analyses should be conducted utilizing correct methods, with adherence to guidelines and including extensive sensitivity analyses. Most importantly, genetic screening strategies should be based on good evidence-based rationales. For these goals, we provide a list of recommendations for good pharmacoeconomic practice deemed useful in the fields of pharmacogenetics and pharmacogenomics, regardless of country and origin of the economic analysis.

Abstract: We investigated the effect of apolipoprotein E (Apoe) on albuminuria in the males of two independent F2 intercrosses between C57BL/6J and A/J mice, using wild-type inbred strains in the first cross and B6-Apoe(-/-) animals in the second cross. In the first cross, we identified three quantitative trait loci (QTL): chromosome (Chr) 2 [LOD 3.5, peak at 70 cM, confidence interval (C.I.) 28-88 cM]; Chr 9 (LOD 2.0, peak 5 cM, C.I. 5-25 cM); and Chr 19 (LOD 1.9, peak 49 cM, C.I. 23-54 cM). The Chr 2 and Chr 19 QTL were concordant with previously found QTL for renal damage in rat and human. The Chr 9 QTL was concordant with a locus found in rat. The second cross, testing only Apoe(-/-) progeny, did not identify any of these loci, but detected two other loci on Chr 4 (LOD 3.2, peak 54 cM, C.I. 29-73 cM) and Chr 6 (LOD 2.6, peak 33 cM, C.I. 11-61 cM), one of which was concordant with a QTL found in rat. The dependence of QTL detection on the presence of Apoe and the concordance of these QTL with rat and human kidney disease QTL suggest that Apoe plays a role in renal damage.

Abstract: Renal impairment, as measured by reduced glomerular filtration rate (GFR) and increased urinary albumin excretion (UAE), is prevalent in patients with chronic heart failure (CHF) and is associated with reduced survival. The prevalence of structural tubular damage in CHF is unknown. We investigated 90 CHF patients and 20 age and sex matched healthy controls, and determined estimated GFR, UAE, N terminal-pro brain natriuretic peptide (NT-proBNP) and urinary neutrophil gelatinase associated lipocalin (NGAL) as a marker for tubular damage. CHF patients had significantly lower averaged estimated GFR (64+/-17 vs 90+/-12 mL/min/1.73 m(2), P<0.0001), but higher NT-proBNP and UAE levels (both P<0.0001). Median urinary NGAL levels were markedly increased in CHF patients compared to controls (175 (70-346) vs 37 (6-58) microg/gCr, P<0.0001). Both serum creatinine (r=0.26, P=0.006) and eGFR (r=-0.29, P=0.002) were significantly associated with urinary NGAL levels as were NT-proBNP and UAE but to a lesser extent. In conclusion, renal impairment in CHF patients is not only characterised by decreased eGFR and increased UAE, but also by the presence of tubular damage, as measured by increased urinary NGAL concentrations.

Abstract: This Practice Point commentary discusses the implementation of an intensive, multifactorial intervention in patients who had proteinuria >3 g/day despite treatment with angiotensin-converting-enzyme inhibitors. In their 'Remission Clinic' in Bergamo, Italy, Ruggenenti et al. implemented an individual titration regimen using ramipril 5-10 mg/day, losartan 50-100 mg/day, verapamil 80-120 mg/day and atorvastatin 10-20 mg/day in successive steps, aiming for a low blood pressure target of <120/80 mmHg and a proteinuria target of <0.3 g/day. They found that patients treated in the Remission Clinic had a much slower decline in estimated glomerular filtration rate than a matched historical reference group treated with 1.25-5.00 mg ramipril (diastolic blood pressure goal <90 mmHg). Only 3.6% of Remission Clinic patients reached end-stage renal disease, compared with 30.4% of the historical controls. No information was provided on the individual responses to the different titration steps; therefore, the contributions of the specific components of the regimen towards the therapeutic benefit cannot be established. The data do, however, encourage an individualized and more active approach to preventing end-stage renal disease in individuals with proteinuric chronic kidney disease.

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Abstract: Advanced glycation end products (AGEs) are involved in diabetic nephropathy. The AGE inhibitor pyridoxamine (PM) is renoprotective in experimental chronic allograft nephropathy supporting its potential in non-diabetic renal damage.

Abstract: The blood pressure increase associated with the cholesteryl ester transfer protein (CETP) inhibitor, torcetrapib is probably attributable to an off-target effect but it is unknown whether activation of the renin-angiotensin-aldosterone system (RAAS) may be related to variation in the plasma CETP level. We questioned whether the plasma CETP level would affect RAAS responsiveness to low sodium diet and the blood pressure response to angiotensin-II infusion in healthy subjects.

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Abstract: Cardiac surgery with cardiopulmonary bypass (CPB) is commonly perceived as a risk factor for decline in renal function, especially in patients with preoperative renal dysfunction. There are few data on the effects of CPB on renal function in patients with mild preoperative renal dysfunction. The purpose of this study was to evaluate renal function in patients with pre-existing mild renal dysfunction undergoing cardiac surgery with CPB.

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Abstract: Randomized clinical trials on progression of renal diseases usually include patients according to criteria for BP, renal function, and proteinuria. There are no data showing that this provides groups with similar baseline rates of renal function loss. Accordingly, the impact of preintervention rate of renal function loss (slope) on outcome of studies has not been established.

Abstract: The risk for multifactorial diseases is determined by risk factors that frequently apply across disorders (universal risk factors). To investigate unresolved issues on etiology of and individual's susceptibility to multifactorial diseases, research focus should shift from single determinant-outcome relations to effect modification of universal risk factors. We present a model to investigate universal risk factors of multifactorial diseases, based on a single risk factor, a single outcome measure, and several effect modifiers. Outcome measures can be disease overriding, such as clustering of disease, frailty and quality of life. "Life course epidemiology" can be considered as a specific application of the proposed model, since risk factors and effect modifiers of multifactorial diseases typically have a chronic aspect. Risk factors are categorized into genetic, environmental, or complex factors, the latter resulting from interactions between (multiple) genetic and environmental factors (an example of a complex factor is overweight). The proposed research model of multifactorial diseases assumes that determinant-outcome relations differ between individuals because of modifiers, which can be divided into three categories. First, risk-factor modifiers that determine the effect of the determinant (such as factors that modify gene-expression in case of a genetic determinant). Second, outcome modifiers that determine the expression of the studied outcome (such as medication use). Third, generic modifiers that determine the susceptibility for multifactorial diseases (such as age). A study to assess disease risk during life requires phenotype and outcome measurements in multiple generations with a long-term follow up. Multiple generations will also enable to separate genetic and environmental factors. Traditionally, representative individuals (probands) and their first-degree relatives have been included in this type of research. We put forward that a three-generation design is the optimal approach to investigate multifactorial diseases. This design has statistical advantages (precision, multiple-informants, separation of non-genetic and genetic familial transmission, direct haplotype assessment, quantify genetic effects), enables unique possibilities to study social characteristics (socioeconomic mobility, partner preferences, between-generation similarities), and offers practical benefits (efficiency, lower non-response). LifeLines is a study based on these concepts. It will be carried out in a representative sample of 165,000 participants from the northern provinces of the Netherlands. LifeLines will contribute to the understanding of how universal risk factors are modified to influence the individual susceptibility to multifactorial diseases, not only at one stage of life but cumulatively over time: the lifeline.

Abstract: Advanced glycation end products (AGEs) are involved in diabetic nephropathy (DN). The AGE formation inhibitor pyridoxamine (PM) is renoprotective in DN and in normoglycaemic obese Zucker rats. In chronic allograft nephropathy (CAN), renal AGE accumulation occurs as well.

Abstract: Angiotensin-converting enzyme (ACE) 2 is thought to counterbalance ACE by breakdown of angiotensin (Ang) II and formation of Ang(1-7). Both enzymes are highly expressed in the kidney, but reports on their regulation differ. To enhance our understanding of the regulation of renal ACE and ACE2, we investigated renal ACE and ACE2 expression during conditions of physiological (low-sodium diet) and pharmacological changes (ACE inhibition) in activity of the renin-angiotensin-aldosterone system (RAAS). Healthy rats were treated with vehicle or lisinopril with either a control or a low-sodium diet, and renal ACE2, ACE and plasma angiotensins were studied. During vehicle treatment, low sodium reduced renal ACE mRNA and activity without affecting ACE2 mRNA or activity and plasma Ang(1-7) and Ang II balance. Lisinopril significantly reduced renal ACE activity without affecting renal ACE2 activity. During ACE inhibition, low sodium reduced both ACE and ACE2 mRNA without affecting ACE2 activity or further reducing ACE activity. Measurements of renal neprilysin activity revealed no significant differences between any of the treatment groups. Plasma Ang(1-7) and Ang II balance is positively shifted towards the beneficial vasopeptide Ang(1-7) by the ACE inhibitor lisinopril, especially during a low sodium intake. In conclusion, modulation of the RAAS, by low sodium intake or ACE inhibition, does not affect renal ACE2 despite major variations in renal ACE. Thus, ACE and ACE2 are differentially regulated by low sodium and ACE inhibition. Therefore, we propose that the beneficial effects of ACE inhibitors are predominantly mediated by modulation of ACE and not ACE2. Whether this also applies to renal disease conditions should be investigated in future studies.

Abstract: Nephrosis-induced endothelial dysfunction is assumed to play a main role in cardiovascular morbidity. Adriamycin-induced proteinuria is a well-established rat model for nephrotic syndrome. However, induction of nephrosis by intravenous adriamycin administration might exert direct adriamycin cardiovasculotoxicity that could obscure or modify nephrosis-induced vascular dysfunction. The present study, therefore, investigated in vitro vascular function in the isolated thoracic aorta and isolated perfused hearts of rats with adriamycin nephrosis, as compared to non-nephrotic adriamycin exposed rats.

Abstract: Transplantation-induced systemic endothelial dysfunction causes severe cardiovascular morbidity and mortality after transplantation. Interventions that improve systemic endothelial function after transplantation and furthermore reduce intragraft vascular dysfunction might improve graft and patient survival. Treatment with the PPARgamma agonist rosiglitazone is an intervention that potentially fulfills these criteria. In this study, we determined the effect of rosiglitazone treatment on transplantation-induced endothelial dysfunction and vasomotor activity in an experimental model for chronic transplant dysfunction in rats.

Abstract: There is large interindividual variability in the antiproteinuric response to blockade of the renin-angiotensin-aldosterone system (RAAS). A low-sodium diet or addition of diuretics enhances the effects of RAAS blockade on proteinuria and BP, but the efficacy of the combination of these interventions is unknown. Therefore, this randomized, double-blind, placebo-controlled trial to determine the separate and combined effects of a low-sodium diet and hydrochlorothiazide (HCT) on proteinuria and BP was performed. In 34 proteinuric patients without diabetes, mean baseline proteinuria was 3.8 g/d, and this was reduced by 22% by a low-sodium diet alone. Losartan monotherapy reduced proteinuria by 30%, and the addition of a low-sodium diet led to a total reduction by 55% and the addition of HCT to 56%. The combined addition of HCT and a low-sodium diet reduced proteinuria by 70% from baseline (all P < 0.05). Reductions in mean arterial pressure showed a similar pattern (all P < 0.05). In addition, individuals who did not demonstrate an antiproteinuric response to losartan monotherapy did respond when a low-sodium diet or a diuretic was added. In conclusion, a low-sodium diet and HCT are equally efficacious in reducing proteinuria and BP when added to a regimen containing losartan and especially seem to benefit individuals who are resistant to RAAS blockade. Combining these interventions in sodium status is an effective method to maximize the antiproteinuric efficacy of RAAS blockade.

Abstract: Glucocorticoids (GCs) are widely used to prevent chronic lung disease in immature newborns. Emerging evidence indicates that GC exposure in early life may interfere with kidney function and is associated with hypertension in later life. In this study, we have investigated the effect of neonatal dexamethasone (DEX) administration on renal function in rats. Male rats were treated with DEX in the first 3 days after birth, controls received saline (SAL). Severe renal damage associated with premature death was found at 50 wks upon DEX treatment, while renal function and morphology were normal in controls. A subsequent time-course study was performed from 2 days to 32 wks. Compared with controls, neonatal DEX administration led to significant and persistent growth retardation. Progressive proteinuria and increased systolic blood pressure were found from 8 wks onwards in DEX-treated animals. Renal alpha-SMA gene expression was elevated from wk 24 onwards and morphological fibrosis was noted at 32 wks of age following DEX treatment. Markedly increased renal gene expression of TNF-alpha and MCP-1 in DEX -treated rats was observed at day 7, probably contributing to the permanent increase in interstitial macrophage numbers that started at 14 days. Permanently elevated renal TGF-beta gene expression was induced by DEX administration from 4 wks onwards. Our data indicate that neonatal DEX administration in rats leads to renal failure in later life, presumably due to an early inflammatory trigger that elicits a persistent pro-fibrotic process that eventually results in progressive renal deterioration.

Abstract: In hypertension, sodium sensitivity (SS) of blood pressure is associated with renal hemodynamic abnormalities related to increased activity of the renal renin-angiotensin aldosterone system (RAAS). The renal mechanisms of SS in normotensives are unknown. Therefore, we studied whether SS is related to renal hemodynamics and renal responsiveness to angiotensin II (AngII) in young healthy adults.

Abstract: Proteinuria is associated with endothelial dysfunction (ED) and increased mortality. We investigated whether urinary protein excretion (UPE) is correlated with markers of ED and whether these markers affect the association of proteinuria with mortality in renal transplant recipients (RTR).

Abstract: No data are available on the absolute risk of either venous thromboembolism (VTE) or arterial thromboembolism (ATE) in patients with nephrotic syndrome. Reported risks are based on multiple case reports and small studies with mostly short-term follow-up. We assessed the absolute risk of VTE and ATE in a large, single-center, retrospective cohort study and attempted to identify predictive factors in these patients.

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Abstract: Renal functional reserve could be relevant for the maintenance of renal function after kidney donation. Low-dose dopamine induces renal vasodilation with a rise in glomerular filtration rate (GFR) in healthy subjects and is thought to be a reflection of reserve capacity (RC). Older age and higher body mass index (BMI) may be associated with reduced RC. We therefore investigated RC in 178 consecutive living kidney donors (39% males, age 48 +/- 11 years, BMI 25.5 +/- 4.1). RC was determined as the rise in GFR ((125)I-iothalamate), 4 months before and 2 months after donor nephrectomy. Before donor nephrectomy, GFR was 114 +/- 20 mL/min, with a reduction to 72 +/- 12 mL/min after donor nephrectomy. The dopamine-induced rise in GFR of 11 +/- 10% was reduced to 5 +/- 7% after donor nephrectomy (p < 0.001). Before donor nephrectomy, older age and higher BMI did not affect reserve capacity. After donor nephrectomy, the response of GFR to dopamine independently and negatively correlated with older age and higher BMI. Moreover, postdonation reserve capacity was absent in obese donors. The presence of overweight had more impact on loss of RC in younger donors. In conclusion, donor nephrectomy unmasked an age- and overweight-induced loss of reserve capacity. Younger donors with obesity should be carefully monitored.

Abstract: The association of renin-angiotensin system (RAS) polymorphisms and left-ventricular hypertrophy (LVH) may depend on the presence of risk factors for LVH, such as renal dysfunction. We studied whether renal function modulates the association between RAS polymorphisms and LVH in a cross-sectional study of 8592 inhabitants of Groningen.

Abstract: The transcription factor c-Jun regulates the expression of genes involved in proliferation and inflammation in many cell types but its role in human renal disease is largely unclear. In the current study we investigated whether c-Jun activation is associated with human renal disease and if c-Jun activation regulates pro-inflammatory and pro-fibrotic genes in renal cells. Activation of c-Jun was quantified by scoring renal expression of phosphorylated c-Jun (pc-Jun) in control human renal tissue and in biopsies from patients with various renal diseases (diabetic nephropathy, focal glomerulosclerosis, hypertension, IgA nephropathy, membranous glomerulopathy, minimal change disease, membranoproliferative glomerulonephritis, systemic lupus erythematosus, acute rejection, and Wegener's granulomatosis); this was correlated with parameters of renal damage. Furthermore, we studied the functional role of c-Jun activation in human tubular epithelial cells (HK-2) stimulated with TGF-beta. Activated c-Jun was present in nuclei of glomerular and tubular cells in all human renal diseases, but only sporadically in controls. Across the diseases, the extent of pc-Jun expression correlated with the degree of focal glomerulosclerosis, interstitial fibrosis, cell proliferation, kidney injury molecule-1 (Kim-1) expression, macrophage accumulation, and impairment of renal function. In HK-2 cells, TGF-beta induced c-Jun activation after 1 h (+40%, p < 0.001) and 24 h (+160%, p < 0.001). The specific c-Jun N-terminal kinase (JNK) inhibitor SP600125 abolished c-Jun phosphorylation at all time points and blunted TGF-beta- or BSA-induced procollagen-1alpha 1 and MCP-1 gene expression in HK-2 cells. We conclude that in human renal disease, the transcription factor c-Jun is activated in glomerular and tubular cells. Activation of c-Jun may be involved in the regulation of inflammation and/or fibrosis in human renal disease.

Abstract: Transplant arteriosclerosis is a leading cause of chronic transplant dysfunction and is characterized by occlusive neointima formation in intragraft arteries. Development of transplant arteriosclerosis is refractory to conventional immunosuppressive drugs and adequate therapy is not available. In this study, we determined the efficacy of the synthetic peroxisome proliferator-activated receptor (PPAR)-gamma agonist rosiglitazone to attenuate the development of transplant arteriosclerosis in rat aortic allografts.

Abstract: Thrombosis is a key factor in the pathophysiology of cardiovascular disease. Important biochemical constituents of the fibrinolytic system, affecting thrombosis, include tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1). Both t-PA and PAI-1 are determined by multiple genetic and environmental factors. We aimed to investigate whether the effects of polymorphism in genes from the renin-angiotensin, bradykinin, and fibrinolytic systems on t-PA or PAI-1 levels are dependent on environmental factors in a large population-based sample from the PREVEND study in Groningen, The Netherlands (n = 2,527). We found strong evidence (P <or= 0.02) for interaction effects of polymorphisms from the bradykinin receptor (BDKRB2) gene and alcohol consumption on t-PA in females and males and on PAI-1 in males. Only suggestive evidence (P <or= 0.10) was present for an interaction effect of the BDKRB2 gene and alcohol consumption on PAI-1 levels in females. Another consistent finding was evidence for an interaction between bradykinin receptor (BDKRB2) gene polymorphisms and body size as measured by body mass index and/or waist-hip-ratio. For each gender and for both t-PA and PAI-1 there was at least one BDKRB2-body size combination that exhibited suggestive (P <or= 0.10), significant (P <or= 0.04) and/or strong evidence (P <or= 0.02) for interaction. In conclusion, the genetic architecture of t-PA and PAI-1 is dependent on the environmental context such as body size and alcohol use. The present study emphasizes the importance of including environmental factors in genetic analyses to fully comprehend the genetic architecture of a specific trait.

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Abstract: Renal impairment is associated with increased mortality in heart failure (HF). Recently, reports suggest that worsening renal function (WRF) is another predictor of clinical outcome in HF. The present study was designed to establish the proportion of patients with HF that exhibits (WRF) and the associated risk for mortality and hospitalization by conducting a systematic review and meta-analysis.

Abstract: Obesity is a risk factor for renal graft loss. Higher body mass index (BMI) in native kidneys is associated with glomerular hyperfiltration. Whether higher BMI in renal transplants is associated with hyperfiltration is unknown. We investigated the impact of BMI on renal hemodynamics 1 year post-transplant. We analyzed glomerular filtration rate (GFR, (125)I-iothalamate) and effective renal plasma flow (ERPF, (131)I-hippurate) in 838 kidney transplants. Data were analyzed for all patients and for the subpopulation without diabetes. Long-term impact of BMI and renal hemodynamics were explored by Cox-regression. With higher BMI GFR and filtration fraction (FF) increased significantly. Multivariate analysis supported impact of BMI on GFR (adjusted r(2) of the model 0.275) and FF (adjusted r(2) of the model 0.158). This association was not explained by diabetes mellitus. On Cox-regression analysis, lower GFR and higher FF were independent determinants of overall graft loss and graft loss by patient mortality. Lower GFR and higher BMI were determinants of death-censored graft loss, with borderline contribution of higher FF. In renal transplants higher BMI is independently associated with higher GFR and FF one year posttransplant, suggesting glomerular hyperfiltration with altered afferent-efferent balance. Mechanisms underlying the long-term prognostic impact of hyperfiltration deserve further exploration.

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Abstract: Infusion of the soluble form of the receptor for advanced glycation end-products (sRAGE) was protective against atherosclerosis and nephropathy in animal models. In this study we investigated determinants of endogenous sRAGE in renal transplant recipients and whether sRAGE was associated with mortality and graft loss.

Abstract: In human renal allografts, recipient-derived cells engrafted in various kidney substructures, have been detected in the long term after transplantation. Here we investigated tubular engraftment and myofibroblast differentiation of recipient-derived cells at short term after experimental kidney transplantation, during a previously described window of regeneration and possible onset of renal interstitial fibrosis.

Abstract: Renal failure in heart failure is related to decreased cardiac output. However, little is known about its association with venous congestion.

Abstract: Plasma hemopexin activity, associated with increased vascular permeability, was evaluated in healthy pregnant and non-pregnant women and in pre-eclamptic women.

Abstract: The purpose of this study was to examine the correlations between plasma levels of plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (t-PA) and cardiovascular disease-related traits in a general population and whether these correlations differed between females and males.

Abstract: Bone marrow-derived cells (BMDC) have been proposed to exert beneficial effects after renal ischemia/reperfusion injury (IRI) by engraftment in the tubular epithelium. However, BMDC can give rise to myofibroblasts and may contribute to fibrosis. BMDC contribution to the renal interstitial myofibroblast population in relation to fibrotic changes after IRI in rats was investigated. A model of unilateral renal IRI (45 min of ischemia) was used in F344 rats that were reconstituted with R26-human placental alkaline phosphatase transgenic BM to quantify BMDC contribution to the renal interstitial myofibroblast population over time. After IRI, transient increases in collagen III transcription and interstitial protein deposition were observed, peaking on days 7 and 28, respectively. Interstitial infiltrates of BMDC and myofibroblasts reached a maximum on day 7 and gradually decreased afterward. Over time, an average of 32% of all interstitial alpha-smooth muscle actin-positive myofibroblasts coexpressed R26-human placental alkaline phosphatase and, therefore, were derived from the BM. BMD myofibroblasts produced procollagen I protein and therefore were functional. The postischemic kidney environment was profibrotic, as demonstrated by increased transcription of TGF-beta and decreased transcription of bone morphogenic protein-7. TGF-beta protein was present predominantly in interstitial myofibroblasts but not in BMD myofibroblasts. In conclusion, functional BMD myofibroblasts infiltrate in the postischemic renal interstitium and are involved in extracellular matrix production.

Abstract: A body mass index (BMI)>or=25 kg/m2 increases the risk for long-term renal damage, possibly by renal hemodynamic factors. As epidemiological studies suggest interaction of BMI and sodium intake, we studied the combined effects of sodium intake and BMI on renal hemodynamics. Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured in 95 healthy men (median age 23 years (95% confidence interval: 22-24), BMI: 23.0+/-2.5 kg/m2) on low (50 mmol Na+, LS) and high (200 mmol Na+, HS) sodium intake. Mean GFR and ERPF significantly increased by the change to HS (both P<0.001). During HS but not LS, GFR and filtration fraction (FF) positively correlated with BMI (R=0.32 and R=0.28, respectively, both P<0.01). Consequently, BMI correlated with the sodium-induced changes in GFR (R=0.30; P<0.01) and FF (R=0,23; P<0.05). The effects of HS on GFR and FF were significantly different for BMI>or=25 versus <25 kg/m2, namely 7.8+/-12.3 versus 16.1+/-13.1 ml/min (P<0.05) and -0.1+/-2.2 and 1.1+/-2.3% (P<0.05). FF was significantly higher in BMI>or=25 versus <25 kg/m2, (22.6+/-2.9 versus 24.6+/-2.4%, P<0.05) only during HS. ERPF was not related to BMI. Urinary albumin excretion was increased by HS from 6.0 (5.4-6.7) to 7.6 (6.9-8.9). Results were essentially similar after excluding the only two subjects with BMI>30 kg/m2. BMI is a determinant of the renal hemodynamic response to HS in healthy men, and of GFR and FF during HS, but not during LS. Consequently, HS elicited a hyperfiltration pattern in subjects with a BMI>or=25 kg/m2 that was absent during LS. Future studies should elucidate whether LS or diuretics can ameliorate the long-term renal risks of weight excess.

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Abstract: Kidney injury molecule-1 (Kim-1) is associated with ischemic and proteinuric tubular injury; however, whether dysregulation of the renin-angiotensin system (RAS) can also induce Kim-1 is unknown. We studied Kim-1 expression in homozygous Ren2 rats, characterized by renal damage through excessive RAS activation. We also investigated whether antifibrotic treatment (RAS blockade or p38 MAP kinase inhibition) would affect Kim-1 expression. At 7 wk of age, homozygous Ren2 rats received a nonhypotensive dose of candesartan (0.05 mg x kg(-1) x day(-1) sc) or the p38 inhibitor SB-239063 (15 mg x kg(-1) x day(-1) sc) for 4 wk; untreated Ren2 and Sprague-Dawley (SD) rats served as controls. Kim-1 mRNA and protein expression were determined by quantitative PCR and immunohistochemistry, respectively, and related to markers of prefibrotic renal damage. Urinary Kim-1 was measured in 8-wk-old Ren2 and SD rats with and without angiotensin-converting enzyme inhibition (ramipril, 1 mg x kg(-1) x day(-1) in drinking water for 4 wk). Untreated Ren2 rats showed a >20-fold increase in renal Kim-1 mRNA (expressed as Kim-1-to-GAPDH ratio): 75.5 +/- 43.6 vs. 3.1 +/- 1.0 in SD rats (P < 0.01). Candesartan and SB-239063 strongly reduced Kim-1 mRNA: 3.1 +/- 1.5 (P < 0.01) and 9.8 +/- 4.2 (P < 0.05), respectively. Kim-1 protein expression in damaged tubules paralleled mRNA expression. Kim-1 expression correlated with renal osteopontin, alpha-smooth muscle actin, and collagen III expression and with tubulointerstitial fibrosis. Damaged tubular segments expressing activated p38 also expressed Kim-1. Urinary Kim-1 was increased in Ren2 vs. SD (458 +/- 70 vs. 27 +/- 2 pg/ml, P < 0.01) rats and abolished in Ren2 rats treated with ramipril (33 +/- 5 pg/ml, P < 0.01). Kim-1 is associated with development of RAS-mediated renal damage. Antifibrotic treatment through RAS blockade or p38 MAP kinase inhibition reduced Kim-1 in the homozygous Ren2 model.

Abstract: Anaemia is prevalent in the chronic heart failure (CHF) population, but its cause is often unknown. The present study aims to investigate the relation between anaemia, renal perfusion, erythropoietin production, and fluid retention in CHF patients.

Abstract: Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor 1 (PAI-1) directly influence thrombus formation and degradation and thereby risk for arterial thrombosis. Activation of the renin-angiotensin system has been linked to the production of PAI-1 expression via the angiotensin II type 1 receptor (AT1R). In addition, bradykinin can induce the release of t-PA through a B2 receptor mechanism. In the present study, we aimed to investigate the epistatic effects of polymorphisms in genes from the renin-angiotensin, bradykinin, and fibrinolytic systems on plasma t-PA and PAI-1 levels in a large population-based sample (n=2527). We demonstrated a strong significant interaction within genetic variations of the bradykinin B2 gene (P=0.002) and between ACE and bradykinin B2 (p=0.003) polymorphisms on t-PA levels in females. In males, polymorphisms in the bradykinin B2 and AT1R gene showed the most strong effect on t-PA levels (P=0.006). In both females and males, the bradykinin B2 gene interacted with AT1R gene on plasma PAI-1 levels (P=0.026 and P=0.039, respectively). In addition, the current study found a borderline significant interaction between PAI 4G5G and ACE I/D on plasma t-PA and PAI-1 levels. These results support the idea that the interplay between the renin-angiotensin, bradykinin, and fibrinolytic systems might play an important role in t-PA and PAI-1 biology.

Abstract: Atherosclerotic renal artery stenosis (ARAS) is associated with hypertension, ischemic nephropathy, and high cardiovascular risk. We review the data on revascularization of the renal artery by percutaneous transluminal renal angioplasty (PTRA) and pharmacological therapy. In patients with severe ARAS and poorly controlled hypertension, PTRA can improve blood pressure control. In patients with rapid renal function loss and severe ARAS, PTRA can improve short-term renal function, but there is no evidence for long-term renoprotection. Recent evidence indicates that ARAS, and incidental renal artery stenosis, considerably increases cardiovascular risk, independent of blood pressure, renal function, and prevalent risk factors. This suggests that revascularization might potentially improve overall prognosis, but no data are available currently. The high cardiovascular risk warrants aggressive pharmacological treatment to prevent progression of the generalized vascular disorder. Ongoing trials will show whether revascularization has added, long-term effects on blood pressure, renal function, and cardiovascular prognosis.

Abstract: The renin-angiotensin-aldosterone system (RAAS) is a key regulator of systemic blood pressure and renal function and a key player in renal and cardiovascular disease. However, its (patho)physiological roles and its architecture are more complex than initially anticipated. Novel RAAS components that may add to our understanding have been discovered in recent years. In particular, the human homologue of ACE (ACE2) has added a higher level of complexity to the RAAS. In a short period of time, ACE2 has been cloned, purified, knocked-out, knocked-in; inhibitors have been developed; its 3D structure determined; and new functions have been identified. ACE2 is now implicated in cardiovascular and renal (patho)physiology, diabetes, pregnancy, lung disease and, remarkably, ACE2 serves as a receptor for SARS and NL63 coronaviruses. This review covers available information on the genetic, structural and functional properties of ACE2. Its role in a variety of (patho)physiological conditions and therapeutic options of modulation are discussed.

Abstract: Regulation of protein kinase activities is crucial in both physiology and disease, but analysis is hampered by the multitude and complexity of kinase networks. We used novel peptide array chips containing 1,152 known kinase substrate sequences to profile different kinase activities in renal lysates from homozygous Ren2 rats, a model characterized by hypertension and angiotensin II (ANG II)-mediated renal fibrosis, compared with Sprague-Dawley (SD) control rats and Ren2 rats treated with an angiotensin-converting enzyme inhibitor (ACEi). Five-wk-old homozygous Ren2 rats were left untreated or treated with the ACEi ramipril (1 mg.kg(-1).day(-1)) for 4 wk; age-matched SD rats served as controls (n = 5 each). Peptide array chips were incubated with renal cortical lysates in the presence of radioactively labeled ATP. Radioactivity incorporated into the substrate motifs was measured to quantify kinase activity. A number of kinases with modulated activities, which might contribute to renal damage, were validated by Western blotting, immunoprecipitation, and immunohistochemistry. Relevant kinases identified by the peptide array and confirmed using conventional techniques included p38 MAP kinase and PDGF receptor-beta, which were increased in Ren2 and reversed by ACEi. Furthermore, insulin receptor signaling was reduced in Ren2 compared with control rats, and G protein-coupled receptor kinase (GRK) activity decreased in Ren2 + ACEi compared with untreated Ren2 rats. Array-based profiling of tissue kinase activities in ANG II-mediated renal damage provides a powerful tool for identification of relevant kinase pathways in vivo and may lead to novel strategies for therapy.