Is Bone Mineral Density Associated with Estrogen Receptor a in Chinese Men? A Pilot Study

This study aimed to assess the associations of telomerase reverse transcriptase ( TERT) and estrogen receptor-alpha (ER alpha) levels with bone mineral density in Chinese men and women. Cancellous bone samples were obtained from femoral neck fracture and osteoarthritis patients. BMD was evaluated by X-ray absorptiometry. Serum levels of BMD markers, including osteocalcin (BGP), tartrate-resistant acid phosphatase 5b (TRACP5b), estradiol (E2) and testosterone (T), were measured by ELISA. Real-time PCR and Western blot were used to assess hTERT, ER alpha, and human protection of telomeres 1 (hPot1) mRNA and protein levels, respectively, in bone specimens. Age, E2, T, TRACP5b, BGP, TNF-alpha, NF-kB and Pot1 mRNA levels, as well as TERT and ER alpha mRNA and protein levels were all correlated with BMD (FN) and BMD (AP) as single variables, except for sex in the case of BMD (FN). Multiple regression analysis revealed sex, age, E2, T, and TERT protein to be significantly associated with BMD (AP); similar findings were obtained with BMD (FN), except for sex. Interestingly, sex, TERT mRNA, and ER alpha protein showed significant correlations with both BMD (FN) and BMD (AP) (all P<0.01) after collinearity diagnostics. Importantly, gender differences were observed for BMD (AP) and BMD (FN) correlations with TERT and ER alpha protein and gene levels. These findings indicate that TERT and ER alpha are associated with BMD in Chinese individuals, with differences observed in these associations between men and women.