Background Cathepsin K is a protease expressed by osteoclasts that plays an important role in osteoclastic mediated bone resorption. It degrades organic bone matrix, primarily type 1 collagen.
Postmenopausal osteoporosis is characterised by an increase in bone resorption that manifests as elevation of bone remodelling makers. This phenomenon starts in the peri-menopausal period. The potential role of cathepsin K levels as markers of bone remodelling in postmenopausal osteoporosis is being evaluated, but there is paucity of data. There is increasing interest in identifying markers able to differentiate the number and activity of osteoclasts to clarify the mechanism of action of current anti-osteoporotic therapies. It is also suggested that such markers might help in the development of more specific novel treatments.
Objectives To evaluate the role of cathepsin K as bone remodelling marker in females with postmenopausal osteoporosis.
Methods Cross sectional study. Two groups were evaluated: postmenopausal females and healthy controls (this group was subdivided into pre and postmenopausal females). Cathepsin K levels in sera were determined by polyclonal antibody ELISA (BI-20432). Data were analysed with STATA10. Differences in cathepsin K levels between groups were determined. A quantile regression model was built to assess cathepsin K leves for the median, first and third quantile according to the variables of interest. A p value of <0.05 was considered as statistically significant.
Results Cathepsin K levels were higher in postmenopausal osteoporotic females than in healthy controls (X2=17.54 y 2 g.l, p<0.01) with a clear dose response gradient (p<0.001).
Conclusions Cathepsin K is a bone remodelling marker in females with postmenopausal osteoporosis. There is a dose response gradient on bone mineral density independently of postmenopausal status, which is maximal in females with postmenopausal osteoporosis and minimal in females with normal bone density.
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Disclosure of Interest None declared