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11.
The studies described here examine the involvement of the fibrinolytic cascade and its endogenous inhibitors in the regulation of activity of matrix metalloproteinases and cartilage degradation related to non-inflammatory joint disease, like osteoarthritis. An interleukin-1-induced model of degradation using [35S]-labeled bovine and human articular cartilage explants was utilized. One goal of these studies was to compare the responses of bovine and human articular cartilage. Degradation was not inhibited by
1-PI, PAI-1,
2-macroglobulin,
2-antiplasmin or TIMP-2, when IL-1 alone was added. Addition of human plasminogen to bovine explants, at concentrations found in human synovial fluid, increased degradation by three to fourfold. Under these conditions, the degradation was inhibited effectively by all of the endogenous inhibitors tested, indicating the presence of a cascade where activated chondrocytes are a source of u-PA. Plasminogen activated by u-PA gives plasmin, which is known to further activate pro-stromelysin. Stromelysin is essential for activation of collegenase. Not only TIMP, but also inhibitors at earlier steps of activation like PAI-1,
2-antiplasmin,
1-PI and
2-macroglobulin inhibited degradation, and could provide cartilage protection in vivo. An experiment with human articular cartilage explants showed that very little or no degradation occurred when human articular cartilage explants were stimulated with interleukin-1 alone. Addition of human plasminogen (at physiologically relevant concentrations) resulted in significant degradation, which was inhibited in the same manner as in bovine explants, by inhibitors of the fibrinolytic cascade and TIMP. TIMP is much more efficient in human explants, indicating the limited participation of human plasmin in the degradation of human cartilage. Although speculative, it is possible that in vivo, cartilage degradation could be promoted not only by TIMP/MMP imbalance, but also accelerated by decreased levels of certain serpins in synovial fluid (e.g. PAIs,
2-antiplasmin and
1-PI).accepted by W. B. van den BergWork supported by OsteoArthritis Science Inc., One Kendall Square, Bldg. 200, Cambridge, MA 01139, USA. 相似文献
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《Fu? & Sprunggelenk》2021,19(2):66-75
The treatment of osteochondral lesions of the talus (OCL) is demanding. Matrix associated techniques are used more and more as a standard, suggestion a more reliable healing. Nevertheless, approaching especially central and medial OCL is still demanding. Medial malleolus osteotomies routineously used, can be a source of morbidity and complications. Improving arthroscopic techniques allow an all-arthroscopic treatment of these defects. 相似文献
19.
Craniofacial development, one of the most complex sequences of developmental events in embryology, features a uniquely transient, pluripotent stem cell-like population known as the neural crest (NC). Neural crest cells (NCCs) originate from the dorsal aspect of the neural tube and migrate along pre-determined routes into the developing branchial arches and frontonasal plate. The exceptional rates of proliferation and migration of NCCs enable their diverse contribution to a wide variety of craniofacial structures. Subsequent differentiation of these cells gives rise to cartilage, bones, and a number of mesenchymally-derived tissues. Deficiencies in any stage of differentiation can result in facial clefts and abnormalities associated with craniofacial syndromes. A small number of conserved signaling pathways are involved in controlling NC differentiation and craniofacial development. They are used in a reiterated fashion to help define precise temporospatial cell and tissue formation. Although many aspects of their cellular and molecular control have yet to be described, it is clear that together they form intricately integrated signaling networks required for spatial orientation and developmental stability and plasticity, which are hallmarks of craniofacial development. Mutations that affect the functions of these signaling pathways are often directly or indirectly identified in congenital syndromes. Clinical applications of NC-derived mesenchymal stem/progenitor cells, persistent into adulthood, hold great promise for tissue repair and regeneration. Realization of NCC potential for regenerative therapies motivates understanding of the intricacies of cell communication and differentiation that underlie the complexities of NC-derived tissues. 相似文献
20.
In 54 cases of ruptured medial semilunar cartilages of the knee joint the bone mineral mass in the distal end of the femur was measured 0–5 years following removal of the injured cartilage. The bone mineral mass was significantly decreased. There was no tendency of restoration of the bone mass with time.Financial support was obtained from the Swedish Medical Research Council No: K69-23X-2737-01 and from the Gustav V 80: th Anniversary Foundation. 相似文献