Locally synthesized estrogen: a novel target in the development of OA

Estrogens are suggested to play an important role in the development of osteoarthritis (OA). Though many clinical and experimental researches have been carried out to investigate the relationship between OA and circulating estrogen or exogenous estrogen, the discrepancy among the results of these studies was also too large to get reconcilable conclusion. In the past several years, locally synthesized estrogens have been found and proved to contribute significantly to the turnover and function of bone tissues independent of circulating estrogen concentrations. We hypothesize that estrogens synthesized locally in bone or synovial tissues have a profound effect on the development OA. Future investigation of local estrogen in bone tissues may give, at least partially, valuable evidences for the etiology and treatment strategy of OA. In our opinion, regulating the amount and effect of locally synthesized estrogen may hold intriguing prospects for the treatment of OA.