Causes of eye pain

In OA, synthesis of MMPs is greatly enhanced and the available inhibitors are overwhelmed, resulting in net degradation. causes of eye pain Thumb pain. Interestingly, stromelysin can serve as an activator for its own proenzyme, as well as for procollagenase and prostromelysin, thus creating a positive feedback loop of proMMP activation in cartilage. (top of page) What factor(s) is responsible for inducing metalloprotease synthesis? One candidate is interleukin-1 (IL-1). IL-1 is a potent pro-inflammatory cytokine that, in vitro, is capable of inducing chondrocytes and synovial cells to synthesize MMPs (slide). causes of eye pain U joints. Furthermore, IL-1 suppresses the synthesis of type II collagen and proteoglycans, and inhibits transforming growth factor-? stimulated chondrocyte proliferation. The presence of IL-1 RNA and protein have been confirmed in OA joints. Thus, IL-1 may not only actively promote cartilage degradation, but may also suppress attempts at repair, in OA. causes of eye pain Penile pain. In addition to these effects, IL-1 induces nitric oxide production, chondrocyte apoptosis, and prostaglandin synthesis, which further contribute to cartilage deterioration. Under normal conditions, an endogenous IL-1 receptor antagonist regulates IL-1 activity. A relative excess of IL-1 and/or deficiency of the IL-1 receptor antagonist could conceivably result in the cartilage destruction that is characteristic of OA. It is likely that other cytokines or particulate material from damaged cartilage may also contribute to this inflammatory, degradative process. (top of page) Can cartilage repair itself? Growth factors are produced locally in cartilage and synovium and are likely to contribute to local cartilage remodeling by stimulating the de novo synthesis of collagen and proteoglycans (slide). Transforming growth factor ? (TGF?) is the best characterized and most potent of the chondrocyte growth factors. Not only does TGF? stimulate de novo matrix synthesis, but it also counteracts cartilage degradation by down regulating IL-1 receptor expression and by increasing IL-1 receptor antagonist release and TIMP expression. Insulin-like growth factor (IGF-1) and basic fibroblast growth factor (b-FGF) are also present in OA cartilage and likely to contribute to reparative attempts, although, as noted, degradation ultimately outstrips repair in OA cartilage. (top of page) Summary In summary, MMPs and pro-inflammatory cytokines (e. g. , IL-1) appear to be important mediators of cartilage destruction in OA. Synthesis and secretion of growth factors and of inhibitors of MMPs and cytokines are apparently inadequate to counteract these degradative forces. Progressive cartilage degradation and OA result.

Causes of eye pain



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