Sabine Krueger-Krasakis

Abstract:

Abstract: Background� Psoriasis is a chronic inflammatory skin disease associated with abnormal vascular expansion in the papillary dermis. Tumour necrosis factor (TNF)-α is a proinflammatory cytokine that can induce antiapoptotic proteins and endothelial cell activation factors in psoriasis. Objectives� The present study investigated the effect of the anti-TNF-α agent etanercept on the expression of endothelial nuclear factor-κB (NF-κB), angiogenic vascular endothelial growth factor (VEGF), endothelial cell marker CD31, antiangiogenic factor thrombospondin-1 (TSP-1), and antiapoptotic factors Bcl-2 and Bcl-xL in psoriasis. Methods� Sixteen patients with moderate-to-severe psoriasis were included in the study and treated with etanercept 50�mg twice weekly subcutaneously for 12�weeks. Biopsies of lesional skin (baseline, weeks 3, 6 and 10) were obtained and immunohistochemically stained with antibodies for CD31, VEGF, TSP-1, NF-κB, Bcl-2 and Bcl-xL. Double immunofluorescence staining for VEGF and CD31 was evaluated with confocal laser microscopy. The terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling (TUNEL) assay was applied for apoptosis detection. Results� Etanercept caused a statistically significant time-dependent reduction in the number of dermal blood vessels, the number of CD31+ cells and VEGF in psoriatic lesions, with induction of endothelial cell apoptosis and statistically significant upregulation of TSP-1 in psoriatic vessels. Immunohistochemical analysis showed significant reduction of NF-κB, Bcl-2 and Bcl-xL expression in endothelial cells during treatment. These changes were accompanied by a marked clinical response. Conclusions� The present findings suggest that treatment with etanercept induces apoptosis, reduces apoptosis-inhibiting factors in psoriatic endothelial cells, and decreases angiogenesis in psoriatic skin.

Abstract: The co-expression of KIT receptor and its ligand stem cell factor (SCF) has been reported in biopsy specimens of Merkel cell carcinoma (MCC). However, the functional role of SCF/KIT in the pathogenesis of this aggressive tumor has not been elucidated. The present study reports expression and effects of SCF and KIT in the Merkel cell carcinoma cell line MCC-1 in vitro. SCF and KIT were endogenously co-expressed in MCC-1 cells. Exogenous soluble SCF modulated KIT receptor mRNA and protein expression, stimulated growth of MCC-1 cells, upregulated endogenous activation of KIT, AKT, and of extracellular signal-regulated kinase (ERK) 1/2 signalling pathway. On the contrary, an inhibitory antibody that neutralized the KIT ligand binding site, reduced growth of MCC-1 cells, as did high doses of the KIT kinase inhibitors imatinib and nilotinib. Also, inhibitors of KIT downstream effectors, U0126 that blocks MEK1/2 as well as wortmannin and LY294002 that inhibit phosphatidylinositol 3-kinase-dependent AKT phosphorylation, inhibited the proliferation of MCC-1 cells. These data support the hypothesis that KIT is activatable by paracrine or autocrine tumor cell-derived SCF and stimulates growth of Merkel cell carcinoma in vitro. Blockade of KIT and the downstream signalling cascade at various levels results in inhibition of Merkel cell carcinoma growth in vitro, suggesting targets for therapy of this cancer. © 2010 Wiley-Liss, Inc.

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Abstract: BACKGROUND: Erysipelas is a superficial form of cellulitis affecting the upper dermis and superficial lymphatics. The widespread use of antibiotics may affect clinical findings and response to therapy of infectious disorders. The purpose of the study was to investigate the epidemiological, clinical, and laboratory features of erysipelas and to compare the results of treatment with penicillin vs. other antibiotic regimens. METHODS: All charts of erysipelas patients treated at the University Hospital of Heraklion, Crete, Greece from 1994 to 2002 were retrospectively studied. RESULTS: Median age of the 99 patients was 54.5 years; 59% were females. The most frequent site involved was the lower extremity (76%), followed by the face (17%) and upper extremity (6%). In 61 patients (62%), a possible entry portal was identified. The most common manifestation of erysipelas was local symptoms and signs (pain, erythema, and swelling) in all patients, together with elevated erythrocyte sedimentation rate (ESR) (60%). Fever was present in 25% of patients. The most commonly used antibiotic was intravenous penicillin G (64%). In the penicillin group, mean duration of fever after treatment initiation was shorter than in the nonpenicillin group (1.7 vs. 4.5 days, P = 0.002). Both treatment failures and recurrences were the same between the two groups. DISCUSSION: The diagnosis of erysipelas can be based on careful examination for local signs and symptoms. The role of ESR in primary diagnosis needs further investigation. Penicillin seems to preserve its fundamental role in the treatment of disease.

Abstract: BACKGROUND/AIMS: KIT receptor has been implicated in the pathogenesis of cancer, either by mutation or autocrine activation. Merkel cell carcinoma (MCC) is a rare KIT-positive cutaneous tumor. We investigated the co-expression of KIT and its ligand stem cell factor (SCF) in MCC. METHODS: Sixteen specimens from 13 MCC patients of various tumor stages were examined by immunohistochemistry for SCF, KIT, Ki67/MIB-1 and cleaved caspase 3 expression, and for apoptosis by TUNEL. RESULTS: KIT was expressed in 13 of 16 tumors, and SCF in 15 of 16 specimens. Co-expression of KIT and SCF was detected in 12 of 16 tumors. KIT and SCF immunoreactivity scores were independent of tumor stage. Ki67/MIB-1 proliferation rates were high, whereas apoptosis rates were low, and did not depend on KIT or SCF expression. CONCLUSION: Co-expression of KIT and SCF in a high percentage of MCC tumors hints to an autocrine mechanism. KIT and SCF expression in primary tumors and in metastases suggests an early event in Merkel cell transformation.

Abstract: Merkel cell carcinoma is a tumor with aggressive biological behavior and limited response to chemotherapy. The present study investigated the effect of interferon (IFN)-alpha on growth and apoptosis of Merkel carcinoma cells in vitro. Proliferation of MCC-1 cell line was reduced dose-dependently by IFN-alpha and diminished when higher IFN-alpha concentrations were used. Additionally, IFN-alpha potently decreased DNA-synthesis and Ki67/MIB-1 proliferation index of MCC-1 cultures. Furthermore, IFN-alpha induced dose-dependently apoptosis of MCC-1 cells as shown by caspase-3 activation, and detection of apoptotic DNA strand breaks and fragmented nuclei. These findings suggest that IFN-alpha may have antitumor activity against Merkel cell carcinoma.

Abstract: Quantitative immunohistochemistry is needed in order to reliably and accurately assess the expression of cellular proteins in tissue. Skin is a difficult tissue for automated image analysis due to its heterogeneous composition and its architecture. In the present study we used a psoriatic skin model to compare the expression of p53 and bcl-2 before and after treatment with anti-tumor necrosis factor-alpha using digital image analysis. Digital photomicrographs were acquired and analyzed with Scion image software in order to obtain the fraction of p53 and bcl-2 immunoreactive cells' area out of the total area investigated. Statistical analysis with ANOVA revealed a significant increase of p53 expression and a decrease of bcl-2 expression in all 3 epidermal layers during the course of therapy (p<0.001). The results were in line with the conventional histopathological evaluation using an arbitrary scale to grade the extent and intensity of the staining. So, the estimation of volume fraction of immunohistochemically labelled cells in skin tissue can be performed easily and rapidly using commonly available image analysis software and provides reproducible and unbiased numerical estimations of the amount of cell labelling.

Abstract: A 64-year-old woman presented with erythematous, infiltrative plaques with a central atrophic area on both zygomatic regions. Several yellow-reddish papules were seen at the periphery of the plaques and showed an "apple-jelly" color on diascopy (Fig. 1). No visceral involvement was detected. The past medical history revealed that, at 3 years of age, she had developed an "Oriental sore" on both cheeks that healed with permanent scars. Thirty years later, she noticed an erythematous patch around the scars. She reported a hospital admission 22 years earlier for cutaneous leishmaniasis (CL); this was treated with pentavalent antimonial therapy for 10 days with partial improvement, when she refused further treatment. The lesions worsened in the summer and gradually became disfiguring, which prompted her to seek medical consultation. Laboratory findings were normal. Leishmania antibody titers were negative. Tissue samples were obtained by biopsy from the border of the lesion for culture, polymerase chain reaction (PCR), and histopathologic examination. Histology revealed a dermal infiltrate with tuberculoid granulomas surrounded by lymphocytes, histiocytes, and some plasma cells, but no caseation necrosis. A few Leishmania organisms were found on careful searching (Fig. 2). Leishmania tropica was identified by culture and PCR. A diagnosis of leishmaniasis recidiva cutis (LRC) was made on the basis of the anamnestic data together with the clinical, histopathologic, biologic, and molecular findings. Complete regression was achieved with meglumine antimoniate (Glucantime) given intramuscularly (15 mg Sb(V)/kg/day for 15 days) and cryosurgery with liquid nitrogen. No recurrence was noted during a 12-month follow-up period.

Abstract: BACKGROUND: Tumour necrosis factor (TNF)-alpha blockade using infliximab, a chimeric anti-TNF-alpha antibody, is an effective treatment for plaque-type psoriasis, inducing remission in about 80% of patients. OBJECTIVES: To examine infliximab-induced programmed cell death (PCD) of keratinocytes in psoriatic plaques on serial skin biopsy samples. METHODS: Five patients with moderate to severe plaque-type psoriasis received infliximab infusions intravenously (5 mg kg(-1)) at weeks 0, 2 and 6. Biopsies of nonlesional and lesional skin (days 0, 5, 14 and 21) were obtained. Conventional microscopy was used to examine the morphology of the psoriatic keratinocytes. In situ detection of apoptosis was performed by electron microscopy and by immunohistochemical staining with anti-p53 and anti-caspase-3 antibodies. Results Infusion of infliximab induced a clinical response in all five patients with psoriasis, with a mean Psoriasis Area and Severity Index improvement of 24.8% already at day 5. This was accompanied by significant histopathological changes in the skin biopsy samples after infliximab treatment. Light and electron microscopic evaluation revealed apoptosis-like morphological changes in lesional keratinocytes, i.e. nuclear condensation, chromatin fragmentation and cytoplasmic vesiculation, visible already after the first infusion. These damaged keratinocytes stained positively for p53, but not for active caspase-3. CONCLUSIONS: The effects of infliximab in psoriasis extend beyond merely anti-inflammatory actions, and may include caspase-independent PCD of lesional keratinocytes. The PCD of keratinocytes may be an important mechanism that could explain at least in part the rapid and sustained therapeutic effect of infliximab in psoriasis.

Abstract: BACKGROUND: Grape farmers are exposed to a variety of agents capable of inducing occupational skin disease. We conducted a study to measure the prevalence of skin symptoms and work-related skin symptoms among grape farmers in the Malevisi region of Crete and to provide data on associated risk factors. METHODS: One hundred twenty grape farmers and 100 controls participated in the study. The protocol consisted of a questionnaire, skin prick tests for 16 common allergens, and measurement of specific IgE antibodies against 8 allergens. RESULTS: Self-reported itchy rash (OR, 2.31; 95%CI, 1.10-4.84, P<0.05) within the last 12 months, and work-related itchy rash (OR, 4.08; 95%CI, 1.01-20.33, P<0.05) were significantly higher in grape farmers than in controls, after adjusting for age and sex. Sensitization to pollens (OR, 4.20; 95% CI, 1.41-12.82, P<0.01) and allergic rhinitis (OR, 3.06; 95% CI, 1.21-8.28, P<0.05) were found to be significantly associated with self-reported itchy rash in the grape farmers group. CONCLUSIONS: Grape farmers reported skin symptoms more frequently than non-exposed controls, and IgE-mediated sensitization to pollens was found to be significantly associated with the reported symptoms. Further studies are needed to evaluate the impact of specific occupational agents on skin diseases among grape farmers.

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Abstract: BACKGROUND: Comparative analysis of the incidence rates and epidemiological features of cutaneous malignant melanoma (CMM) between different ethnic groups exposed to varying environmental factors is critical for consideration of the causes of CMM but can also be utilized in a public health approach to control of the disease. OBJECTIVES: To compare incidence rates and clinical features of CMM in a Greek and a central European population (central Baden-Württemberg, Germany). METHODS: Incident cases of CMM were traced in all hospitals of the island of Crete for the period 1999-2002. Age-standardized incidence rates per 100 000 inhabitants per year for the European Standard Population were calculated based on the Cretan population statistics. A comparison was performed between the Cretan findings and those of southern Germany as registered by the hospital-based Central Malignant Melanoma Registry, which likewise documents more clinical features than normally recorded by population-based cancer registries. RESULTS: Mean incidence rates in Crete for 1999-2002 were 4.01 per 100 000 inhabitants per year for males and 4.05 for females as compared with 10.6 for males and 11.1 for females in southern Germany. There were striking differences in the clinical characteristics of CMMs, with significantly higher tumour thickness in Crete (median 1.4 mm vs. 0.7 mm in southern Germany). Correspondingly, significantly more nodular melanomas were observed in Crete (29%) as compared with southern Germany (11%). CONCLUSIONS: Incidence of CMM in Crete, with about four cases per 100 000 inhabitants per year, is clearly higher than previously estimated, and there is an urgent necessity for earlier recognition of CMM in Crete. However, the incidence of CMM in southern Germany is much higher.

Abstract: BACKGROUND: For Greece, no data regarding the incidence of cutaneous melanoma (CM) have been reported. In this report, we present epidemiologic data for CM on Crete, an island in southern Greece, during the years 1999-2002. We attempt a comparison with corresponding data reported for the Italian population. METHODS: One hundred and two CM patients of Cretan origin with primary CM first diagnosed between the years 1999-2002 were interviewed and underwent complete skin examination by the same two experienced dermatologists. Crude and/or age-standardized incidence rates were calculated for Crete as a whole, as well as for each one of the four prefectures of the island. RESULTS: The age-standardized incidence rate according to the Greek population was 4.6 per 100,000 person-years for men and 4.7 per 100,000 person-years for women. The crude incidence rates did not differ significantly between the four prefectures. Significant differences between Cretan and Italian CM patients were found in terms of gender, age at diagnosis, anatomic site and histogenetic type of CM, hair color, skin reaction to sun exposure, history of sunburn before the age of 15 years, presence of solar lentigines, and total common nevus count. CONCLUSIONS: The incidence of CM on Crete is higher than that estimated for the whole of Greece and comparable with the incidence reported for other southern European countries.

Abstract: Specific heterodimers of alpha and beta integrins are implicated in mediating adhesion and functional activation of mast cells to extracellular matrix (ECM) proteins, determining thus homing, secretion and tissue distribution of these cells. In the present study, we have examined integrin expression and associated morphological features of mast cells adhering to ECM, also depending on cell activation and under the influence of protein kinase C (PKC) inhibitors. Unstimulated and PMA-activated human leukaemic mast cells (HMC-1 line) were allowed to adhere to fibronectin or vitronectin-coated surfaces. Cells were specifically stained for actin, beta(1, )alpha(1)-alpha(6), alpha(v) and alpha(v)beta(5 )integrins and were evaluated by fluorescence microscopy and confocal laser scan microscopy. Spontaneously adhering cells rapidly assumed an oblong shape, with pronounced formation of filopodia, whereas PMA-stimulated cells were round in shape. Clustering of integrins on filopodia and on comma-like shapes at the cell circumference in rounded cells was noted only for alpha(4), alpha(5) and beta(1 )chains in fibronectin-adhering cells, and for alpha(v) and alpha(v)beta(5) chains in vitronectin-adhering cells. On double staining, clustered integrins co-localized with each other and with actin at the cell membrane and along intracellular tension lines of actin filaments. PKC inhibitors affected the shape of cells, but adhesion was maintained. These data provide a morphological correlate to previously reported functional studies, demonstrating clustering of selected integrins during ECM adhesion at the cell membrane. This was associated with alignment of integrins along actin filaments within the cytoplasm, PKC signalling and changes in shape and activation of mast cells.

Abstract: We report a case of cutaneous alternariosis in a 69-year-old male patient. During hospitalization for treatment of the skin disorder, acute myeloid leukaemia was diagnosed. He received multiple chemotherapeutic agents but the leukaemia remained refractory to therapy and the patient died. The clinical picture, diagnosis and treatment of cutaneous alternariosis will be discussed and a review of the literature regarding patients with haematological diseases will be given.

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Abstract: Mast cells generate and release histamine during anaphylactic reactions, and there is pharmacological evidence that histamine regulates this process via specific receptors. Therefore, we examined human leukemic (HMC-1) and normal skin mast cells for the expression of all four currently known histamine receptors. Both cell types expressed H2 and H4 receptors at mRNA and protein levels, whereas H3 receptor specific mRNA and receptor protein was undetectable. Similarly, immunohistochemistry of cutaneous tissue showed an absence of H3 receptor in these cells. Despite transcription of mRNA, H1 receptor protein was only moderately expressed in HMC-1 cells and was virtually absent in skin mast cells. Furthermore, only H1, H2, and H4 receptors were detectable by Western blot analysis of HMC-1 cells. Radiolabeled histamine binding was strongly inhibited only by H2 (ranitidine)- and H3/H4 (FUB 108)-specific antagonists. Histamine-induced increase of cAMP was inhibited by the H2 receptor antagonist famotidine, whereas induction of IP3 was not observed, making signaling via the H1 receptor unlikely. These data show that human mast cells constitutively express primarily H2 and H4 receptors and that H2 receptors are functionally linked to cellular processes. They provide new insights into the mechanisms that govern auto- and paracrine histamine-induced mast cell functions.

Abstract: The aim of this study was to reveal differences in the epidemiology and to identify significant risk factors for cutaneous melanoma (CM) in a relatively dark-skinned, chronically sun-exposed Caucasian population. This group is considered to have a low risk for this tumour. One hundred and ten newly diagnosed patients with primary CM and 110 age- and gender-matched controls, all of Cretan origin, were interviewed and underwent a complete skin examination. Solar keratoses odds ratio (OR) 6.2 and lentigines (OR 2.2), common and atypical naevi (OR 5.4 and 3.0, respectively), blonde or red hair colour (OR 3.1), skin phototypes I/II (OR 1.8), as well as total sun exposure (weeks per year) (OR 1.03), were all significantly associated with CM risk in a multivariate logistic regression analysis. In the relatively dark-skinned Cretan population, sun exposure indices represent the most important risk markers for CM which contrasts with data from fair-skinned Caucasian populations where melanocytic naevi are the main risk factors.

Abstract: Integrins are expressed on mast cells and constitute an essential prerequisite for the accumulation of the cells at sites of inflammation. In order to clarify a potential contribution of inflammatory cytokines to this process, we have studied the modulation of integrin expression and adhesion of immature human mast cells (HMC-1) to extracellular matrix proteins by interleukin-6, tumor necrosis factor alpha, interferon-alpha and interferon-gamma. Corticosteroids were used for comparison. On fluorescence-activated cell sorter analysis, preincubation of cells for 48 h with different concentrations of interleukin-6 induced a significant, up to 40%, increase of alpha v alpha 5, CD49b (alpha 2), CD49e (alpha 5), CD49f (alpha 6), and CD51 (alpha v). In contrast, different concentrations of tumor necrosis factor alpha, interferon-alpha, interferon-gamma, and dexamethasone (10-8-10-10 M) inhibited expression of adhesion receptors by up to 60%, reaching significance for some but not all integrins. On semiquantitative polymerase chain reaction analysis, interleukin-6, the other cytokines, and corticosteroids significantly modulated expression of alpha1, alpha v and alpha 5 integrin chains at mRNA level. Functional significance of these findings was proven in adhesion assays using fibronectin, laminin, and vitronectin, with interleukin-6 causing significant enhancement of adhesion in all cases, tumor necrosis factor alpha and dexamethasone inducing significant reduction of adhesion to fibronectin and laminin, and interferon-gamma significantly inhibiting adhesion to fibronectin only. Specificity of interleukin-6-induced changes was demonstrated using antibodies against alpha1 and alpha 5 integrins in unstimulated and interleukin-6-prestimulated cells. These data show that interleukin-6 stimulates mast cell adhesion to extracellular matrix and thus allows for the accumulation of the cells at tissue sites by enhancing integrin expression, whereas tumor necrosis factor alpha, interferon-alpha, interferon-gamma, and dexamethasone downmodulate this process.

Abstract: In order to explore possible mechanisms involved in the previously documented turnover of mast cell subpopulations in human cutaneous scars, we have examined selected factors known to stimulate and/or modulate mast cell hyperplasia (SCF, NGF, TGFbeta1, GM-CSF) and their receptors in human cutaneous scar tissue. On immunohistochemistry, numbers of SCF- and TGFbeta1-positive cells were significantly increased in the epidermis and throughout the dermis in scars (n = 27) of varying ages (4-369 d old), compared with normal skin (n = 12). Furthermore, TRbetaRI, II, and the NGF-p75 receptors were significantly increased in the epidermis, TRbetaRI and NGF-TrkA throughout the dermis, and TRbetaRII, NGF-p75, and GM-CSFR only in the mid- and lower dermis of scars. NGF and GM-CSF expression was in contrast scarce and weak, with no differences between normal skin and scars. In tissue extracts, mRNA levels of SCF, TGFbeta1, TRbetaI and II, and both NGF-receptors, but not GM-CSFR, were significantly increased as well. TRbetaI and II were identified in up to 90% and 83%, respectively, of isolated normal skin mast cells on flow cytometry, and GM-CSFR and NGFR-p75 were identified on 70% and 73%, respectively, of avidin-positive normal mast cells on double immunofluorescence microscopy. As described before for the SCF receptor KIT, GM-CSFR and NGFR-p75 were partly or entirely downregulated on avidin-positive mast cells in scars. The marked upregulation of TGFbeta1, its type I and II receptors, and SCF suggest that these factors play a major role in the orchestration of mast cell increase in human cutaneous scars whereas the role of NGF and GM-CSF is less clear, despite the significant upregulation of their receptors.