Abstract: Osteoarthritis is a chronic disease characterized by irreversible damage to joint structures, including loss of articular cartilage, osteophyte formation, alterations in the subchondral bone and synovial inflammation. Pain, functional disability and impairment of health-related quality of life are major complaints in patients with osteoarthritis. Several compounds have been investigated for their positive effects on the relief of clinical symptoms and improvement of structural changes in osteoarthritis. It has been shown that chondroitin sulfate interferes with the progression of structural changes in joint tissues and is used in the management of patients with osteoarthritis. This review summarizes data from relevant reports describing the mechanisms of action of chondroitin sulfate involved in the beneficial effects of the drug.
Abstract: A major and early feature of cartilage degeneration is proteoglycan breakdown. Matrix metalloprotease (MMP)-13 plays an important role in cartilage degradation in osteoarthritis (OA). This MMP, in addition to initiating collagen fibre cleavage, acts on several proteoglycans. One of the proteoglycan families, termed small leucine-rich proteoglycans (SLRPs), was found to be involved in collagen fibril formation/interaction, with some members playing a role in the OA process. We investigated the ability of MMP-13 to cleave members of two classes of SLRPs: biglycan and decorin; and fibromodulin and lumican. SLRPs were isolated from human normal and OA cartilage using guanidinium chloride (4 mol/l) extraction. Digestion products were examined using Western blotting. The identities of the MMP-13 degradation products of biglycan and decorin (using specific substrates) were determined following electrophoresis and microsequencing. We found that the SLRPs studied were cleaved to differing extents by human MMP-13. Although only minimal cleavage of decorin and lumican was observed, cleavage of fibromodulin and biglycan was extensive, suggesting that both molecules are preferential substrates. In contrast to biglycan, decorin and lumican, which yielded a degradation pattern similar for both normal and OA cartilage, fibromodulin had a higher level of degradation with increased cartilage damage. Microsequencing revealed a novel major cleavage site (... G177/V178) for biglycan and a potential cleavage site for decorin upon exposure to MMP-13. We showed, for the first time, that MMP-13 can degrade members from two classes of the SLRP family, and identified the site at which biglycan is cleaved by MMP-13. MMP-13 induced SLRP degradation may represent an early critical event, which may in turn affect the collagen network by exposing the MMP-13 cleavage site in this macromolecule. Awareness of SLRP degradation products, especially those of biglycan and fibromodulin, may assist in early detection of OA cartilage degradation.
Abstract: Articular cartilage is optimised for bearing mechanical loads. Chondrocytes are the only cells present in mature cartilage and are responsible for the synthesis and integrity of the extracellular matrix. Appropriate joint loads stimulate chondrocytes to maintain healthy cartilage with a concrete protein composition according to loading demands. In contrast, inappropriate loads alter the composition of cartilage, leading to osteoarthritis (OA). Matrix metalloproteinases (MMPs) are involved in degradation of cartilage matrix components and have been implicated in OA, but their role in loading response is unclear. With this study, we aimed to elucidate the role of MMP-1 and MMP-3 in cartilage composition in response to mechanical load and to analyse the differences in aggrecan and type II collagen content in articular cartilage from maximum- and minimum-weight-bearing regions of human healthy and OA hips. In parallel, we analyse the apoptosis of chondrocytes in maximal and minimal load areas. Because human femoral heads are subjected to different loads at defined sites, both areas were obtained from the same hip and subsequently evaluated for differences in aggrecan, type II collagen, MMP-1, and MMP-3 content (enzyme-linked immunosorbent assay) and gene expression (real-time polymerase chain reaction) and for chondrocyte apoptosis (flow cytometry, bcl-2 Western blot, and mitochondrial membrane potential analysis). The results showed that the load reduced the MMP-1 and MMP-3 synthesis (p < 0.05) in healthy but not in OA cartilage. No significant differences between pressure areas were found for aggrecan and type II collagen gene expression levels. However, a trend toward significance, in the aggrecan/collagen II ratio, was found for healthy hips (p = 0.057) upon comparison of pressure areas (loaded areas > non-loaded areas). Moreover, compared with normal cartilage, OA cartilage showed a 10- to 20-fold lower ratio of aggrecan to type II collagen, suggesting that the balance between the major structural proteins is crucial to the integrity and function of the tissue. Alternatively, no differences in apoptosis levels between loading areas were found--evidence that mechanical load regulates cartilage matrix composition but does not affect chondrocyte viability. The results suggest that MMPs play a key role in regulating the balance of structural proteins of the articular cartilage matrix according to local mechanical demands.
Abstract: OBJECTIVE: To determine the range and activity of the clinical and biological features of patients aged <40 with Paget's disease of bone. METHODS: A retrospective two centre study of 314 patients with Paget's disease of bone from two university hospitals. The disease was diagnosed by radiological, serum alkaline phosphatase (AP) levels, or clinical features, and bone scintigraphy in most patients. Demographic data, reason for diagnosis, bones affected, disease extent using Coutris' index, complications during progression, and disease activity using Renier's index were assessed. Patients over and under 40 were compared. RESULTS: 18/314 (5.7%) patients were diagnosed before the age of 40; median (SD) age was 35.4 (5.5) (range 18-40) and AP 555.6 (566.3) IU/l (range 70-1949). Coutris' extension index was 12.8 (10.5) and Renier's activity index 35.9 (31.9). Younger patients had more affected bones (p<0.05) than those aged >40, higher level of extension (p<0.05), higher AP value (p = 0.05), and greater incidence of thoracolumbar spine disease. Disease activity did not differ significantly between the groups. CONCLUSIONS: Paget's disease diagnosed before the age of 40 is more extensive but not more active, with higher AP values than in those diagnosed after age 40.
Abstract: BACKGROUND AND OBJECTIVE: Linguistic adaptation and validation into Spanish of the ARTS questionnaire, a self reported instrument designed to measure four osteoarthritis treatment satisfaction dimensions: treatment advantages, treatment convenience, apprehension about treatment and satisfaction with medical care. MATERIAL AND METHOD: Adaptation was performed using conceptual equivalence, supervised by a panel of 6 experts and 4 independent translators, who were in charge of performing translation and back-translation of the items. A sample of patients suffering from knee, hip or column osteoarthritis was used to estimate the psychometric properties of feasibility, reliability, validity and sensitivity to change. Three groups were identified: adequate analgesic effect and tolerability, treatment-switch because of a weak analgesic effect, and treatment- switch due to poor tolerability. The ARTS was administered at baseline, 1 week later for retest, and after 4 weeks of treatment with NSAIDs or Cox II-inhibitors. RESULTS: A sample of 163 patients was formed (67.7 [9.2] years old). No floor or ceiling effects were found, items were well understood and non- response rates were below 1%. Cronbach's alpha for the total scales was 0.85, and the intraclass correlation coefficient was 0.81. Exploratory factor analysis yielded 4 dimensions which were coherent with those proposed by the original authors. Concurrent validity was measured with SF-36, a pain VAS instrument, a treatment compliance VAS, and the Morisky-Green compliance questionnaire. The adapted instrument showed a good discriminatory validity, and it was able to distinguish between patients needing a change in treatment and those who did not need it. It was also sensitive to changes in patients' treatment effectiveness after a 30 days follow up. CONCLUSIONS: A psychometrically valid and conceptually equivalent ARTS questionnaire has been produced to explore satisfaction with treatment in patients with osteoarthritis in Spanish speaking countries.
Abstract: BACKGROUND: Bone scintigraphy used as a diagnostic technique frequently yields non-specific intense uptake by vertebrae. Bone biopsy may therefore be required to establish a diagnosis in cases of Paget's disease of bone. The aim of the study was to ascertain the sensitivity and specificity of two new images-heart sign and clover sign-in Paget's disease of bone. METHODS: Two expert rheumatologists analyzed 294 bone scintigraphies of patients with vertebral involvement: 204 without and 90 with Paget's disease. The presence or absence of the clover or heart signs was determined in each scintigraphy. A specificity and sensitivity study was performed with the data obtained. A study of concordance was made between two radiologists blinded to the real diagnosis. Each one analyzed 120 scintigraphies for the presence and absence of the signs: 40 with Paget's disease and clover and/or heart signs (selected from the initial 90 cases), 40 with Paget's disease with neither sign and 40 selected from the pool of 4000 scintigraphies of patients with vertebral involvement, with images easily mistaken for these signs (vertebral collapse, osteoarthritis and bone metastases). Kappa statistics were calculated. FINDINGS: Sensitivity of both signs for Paget's disease of bone was low: 44% (95% CI 34.0 to 55.3). However, specificity was excellent: 100% (95% CI 98.2 to 100). Inter-radiologist concordance was almost perfect: Kappa 0.86 (95% CI 0.77 to 0.95). INTERPRETATION: The heart and clover signs are highly specific (probably pathognomonic) of Paget's disease of bone. In cases with doubtful radiologic images, these findings on scintigraphic vertebral images may afford a definitive diagnosis of Paget's disease of bone and thus obviate further confirmatory invasive diagnostic procedures.
Abstract: Overlap syndromes are a spectrum of diseases with clinical features of two or more classic connective tissue diseases. Polymyositis or dermatomyositis that is associated with features of systemic sclerosis, also called sclerodermatomyositis, is an uncommon overlap syndrome, with a rare antibody directed against the nucleolar antigen PM-Scl. This disease generally has good prognosis. We report a case of sclerodermatomyositis with an aggressive pulmonary and articular course.
Abstract: BACKGROUND: To describe the clinical and laboratory features of Paget's disease of bone at the time of diagnosis. PATIENTS AND METHOD: This multicenter and retrospective study included 314 patients. Diagnosis was performed by means of characteristic radiological findings and typical bone scintigraphy. The variables analyzed included: epidemiological variables, cause of diagnosis, bone involvement, disease extension (Coutris index), complications, alkaline phosphate (AP) levels and disease activity (Renier index). RESULTS: There were 159 (50.5%) males and the mean age was 64.9 years (SD 12.6). Diagnosis was casual in 228 (72.6%) patients. Polyostotic involvement was detected in 201 (63.9%) patients. More common locations were pelvis, skull and lumbar spine. Sacrum was more frequently involved in men than in women (p < 0.05), whereas skull involvement was more common in women (p < 0.05). The number of bones involved was 3.1 SD 3 and the percentage of skeletal involvement was 8.7 % (SD 6.5). One hundred ninety eigth (63%) patients had complications. The disease was active in 242 (77%) patients with a mean AP value of 377 IU/L (SD 493); the activity of the disease measured by the Renier index was 34 (SD 46); the activity was greater in the skull and the humerus. CONCLUSIONS: Paget's disease of bone is usually asymptomatic. Polyostotic involvement and activity are common at the time of diagnosis. Knowledge of the extension and activity by means of a mathematical model may aid to make therapeutical decisions.
