Circulating Biomarkers Related to Osteocyte and Calcium Homeostasis Between Postmenopausal Women with and without Osteoporosis

BACKGROUND: The currently available bone turnover markers are mostly derived from osteoblasts or osteoclasts. Protein markers derived from osteocytes, the most abundant bone cells that can regulate bone turnover activities by other cells, are less explored.

OBJECTIVE: This study aimed to compare the circulating markers of osteocytes and calcium homeostasis between Malaysian postmenopausal women with and without osteoporosis.

METHODS: Postmenopausal women with (n=20) or without osteoporosis (n=20) as determined by dual- energy X-ray absorptiometry were randomly drawn from a bone health cohort. Their fasting blood was collected and assayed by a multiplex immunoassay panel.

RESULTS: The results showed that osteoprotegerin and sclerostin levels were significantly lower among postmenopausal women with osteoporosis than the normal control. No significant differences in other markers were observed between the two groups. Sclerostin level correlated positively with spine Bone Mineral Density (BMD), while 25-hydroxyvitamin D correlated negatively with hip BMD in the control group. No significant correlation was observed between other markers with spine or hip BMD.

CONCLUSION: These data provide an insight into the possible roles of osteocyte markers, especially osteoprotegerin and sclerostin, in classifying subjects with osteoporosis. However, the lack of association between these markers and BMD indicates that osteoporosis is a complex and multifactorial condition.