SAT0471 Cathepsin K is A Bone Remodelling Marker in Females with Postmenopausal Osteoporosis
Authors: I. Jiménez-Moleόn, P. Morales, M. Juarez, E. Raya
Journal: Annals of the Rheumatic Diseases (2014)

<h3>Background</h3> 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. <h3>Objectives</h3> To evaluate the role of cathepsin K as bone remodelling marker in females with postmenopausal osteoporosis. <h3>Methods</h3> 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 &lt;0.05 was considered as statistically significant. <h3>Results</h3> Cathepsin K levels were higher in postmenopausal osteoporotic females than in healthy controls (X<sup>2</sup>=17.54 y 2 g.l, p&lt;0.01) with a clear dose response gradient (p&lt;0.001). <h3>Conclusions</h3> 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. <h3>References</h3> Dodds RA, James IA, Rieman D et al.: Human osteoclast Cathepsin K is Processed Intracellulary Prior to Attachment and Bone Resorption. J of Bone and Miner Res 2001; 16 (3): 478-486 Garnero P, Borel O, Byrjalsen I et al.: The collagenotic activity of cathepsin K is unique among mammalian proteinases. J Biol Chem 1998; 273:32347-32352. Meier C, Meinhardt U, Greenfield JR et al.: Serum cathepsin K concentrations reflect osteoclast activity in women with postmenopausal osteoporosis and patient with Paget9s disease Muñoz Torres M, Reyes García R, Mezquita Raya P, et al.: Serum Cathepsin K as a marker of bone metabolism in postmenopausal women treated with alendronate. Maturitas 2009, doi: 10.1016/j.maturitas.2009.09.011. Reyes García R, Muñoz Torres M. Cathepsin K: Biological aspects and therapeutic possibilities. Med Clin (Barc). 2008 Jul 12:131(6):218-20. Tezuka K, Tezuka Y, Maejima A et al.: Molecular cloning of a posible cysteine proteinasa predominantly expressed in osteoclast. J Biol Chem 1994; 269:1106-1109 <h3>Disclosure of Interest</h3> None declared <h3>DOI</h3> 10.1136/annrheumdis-2014-eular.3416