1,721,215 research outputs found
Biologic therapy with anti-TNFalpha in spondyloarthritides and other autoimmune diseases
No full textENTHESOPATHY: THE COMMON PATHOLOGIC HALLMARK OF SERONEGATIVE SPONDYLOARTHROPATHIES (SNSA)
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The pathophysiology of osteoarthritis
No full textOsteoarthritis (OA) is a complex disease whose pathogenesis includes the contribution of biomechanical and metabolic factors which, altering the tissue homeostasis of articular cartilage and subchondral bone, determine the predominance of destructive over productive processes. A key role in the pathophysiology of articular cartilage is played by cell/extra-cellular matrix (ECM) interactions, which are mediated by cell surface integrins. In a physiologic setting, integrins modulate cell/ECM signaling, essential for regulating growth and differentiation and maintaining cartilage homeostasis. During OA, abnormal integrin expression alters cell/ECM signaling and modifies chondrocyte synthesis, with the following imbalance of destructive cytokines over regulatory factors. IL-1, TNF-alpha and other pro-catabolic cytokines activate the enzymatic degradation of cartilage matrix and are not counterbalanced by adequate synthesis of inhibitors. The main enzymes involved in ECM breakdown are metalloproteinases (MMPs), which are sequentially activated by an amplifying cascade. MMP activity is partially inhibited by the tissue inhibitors of MMPs (TIMPs), whose synthesis is low compared with MMP production in OA cartilage. Intriguing is the role of growth factors such as TGF-beta, IFG, BMP, NGF, and others, which do not simply repair the tissue damage induced by catabolic factors, but play an important role in OA pathogenesis
Metabolic activity of chondrocytes in human osteoarthritis as a result of cell-extracellular matrix interactions
No full textTHE INHIBITOR OF COSTIMULATION OF T CELLS: ABATACEPT
No full textOBJECTIVE: T cell costimulation is a key point in the regulation of immune tolerance, immune response, and autoimmunity. T cell activation does not take place upon the simple engagement of T cell receptor; a second signal is needed to fully stimulate T cells. There are a variety of molecules that can act as costimulators, and among those CD28/CD80 signaling plays a crucial role in modulating T cell response. Cytotoxic T lymphocyte antigen-4, CD152 (CTLA4) is a physiologic antagonist of CD28, and abatacept, a synthetic analog of CTLA4, has recently been approved to treat rheumatoid arthritis. An abnormal T cell activation is also believed to sustain psoriatic disease both at skin and joint sites. We aimed to evaluate the rationale of blocking CD28/CD80 signaling and the possible use of abatacept for treating psoriatic arthritis (PsA). METHODS: We reviewed the role of CD28/CD80 signaling in promoting T cell inflammation in psoriasis and the effects of CTLA4 modulation in experimental models of psoriasis and in humans. RESULTS: CD28/CD80 seems to be crucial in stimulating T cell activation and inflammation in psoriasis, and its inhibition by CTLA4 analogs or by anti-CD28 blocking antibodies is effective against psoriasis. Few data are available on abatacept, which seems to be valuable for the treatment of PsA but less useful in the therapy of skin psoriasis. CONCLUSION: Although the CD28 molecule is crucial in activating T cells and inflammation in psoriasis, data on the efficacy of abatacept in the treatment of PsA are still not conclusiv
Obesity and Inflammation – Targets for OA Therapy
No full textObesity is one of the main risk factors for osteoarthritis (OA). For many years the association of obesity and OA has been simply attributed to the effects of overload on weight-bearing joints, and epidemiological surveys have shown a strict correlation between an increased body mass index and the severity of knee or hip OA, as well as some relief of pain and disability following weight loss. Instead, there is now a growing body of evidence that obesity is a complex syndrome in which an abnormal activation of neuroendocrine and pro-inflammatory pathways leads to an altered control of food intake, fat expansion and metabolic changes. Activated white adipose tissue increases the synthesis of pro-inflammatory cytokines, such as IL-6, IL-1, IL-8, TNFalpha, IL-18, while regulatory cytokines, such as IL-10, are decreased. Adipocytes also produce peculiar cytokines, namely adipokines, that exert multiple effects, being capable of promoting synovial inflammation, cartilage degrading enzymes, and bone matrix remodeling. Furthermore, pro-inflammatory cytokines stimulate adipocytes to synthesize neuropeptides, such as substance P and nerve growth factor, that have been shown to be critical in regulating both the appetite and cartilage homeostasis. In this scenario, where the influence of obesity on OA stems from a complex interaction of genetic, metabolic, neuroendocrine, and biomechanical factors, there may be various different potential targets for OA therap
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