Bone fracture and distraction osteogenesis in animal models are current topics of study in this lab. We are also studying the effect of drugs on ligament healing. Proteoglycans are known to inhibit mineral formation in vitro . The presence of stromelysin in the physeal growth plate, as determined by western blot analysis, is consistent with the hypothesis that MMP-3 is involved in mineralization by degrading aggrecan and thus allowing calcification to occur. Furthermore, mRNA expression of stromelysin has been demonstrated in the growth plate by northern and in situ hybridization analysis.
Studies are underway on the effects of Vitamin D metabolites on osteoblast function.
Both metabolites increased steady state mRNA levels for osteocalcin, osteonectin, and vitamin D 24-hydroxylase to varying extents. These findings are relevant to the vitamin D stimulation of bone formation and suppression of bone resorption. Alterations in the expression of integrins by cancer cells has been correlated with increased tumor pro-gression, invasiveness, and metastatic potential. This finding is in agreement with a recent report on INT alpha5 and INT alpha1 production in some of these cell lines, determined by immunocytochemical staining. INT alpha5, in conjunction with INT alpha1, binds to fibronectin and denatured collagen.