Endocrine Abstracts

Adiponectin and leptin have been described as potential contributors to bone metabolism. The effect of anticatabolic drugs on these adipokines and their relationship with bone metabolism have not been clearly clarified.

Aims: (1) Evaluate adiponectin and leptin levels in osteoporosic postmenopausal women and their relationship with BMD, bone turnover and osteoclastogenesis markers. (2) Analyze changes on adiponectin and leptin levels after treatment with raloxifene or alendronate. We selected 53 untreated women (63±7 years) with postmenopausal osteoporosis divided into two groups: women treated with raloxifene (60 mg/day; n=20) or alendronate (70 mg/week; n=33) during one year. All of them received calcium and vitamin D supplements. We determined at baseline and after 12 months of treatment: anthropometric data, OPG, E2, IGF-I, adiponectin, leptin, 25-hydroxyvitamin D, iPTH, osteocalcin, BALP, ALP, TRAP and BMD in lumbar spine (LS), femoral neck (FN) and total hip (TH).

Results: At baseline, leptin and adiponectin serum levels were 1371.4±822.4 pM/ml and 42.24±26.1 μg/ml, respectively. Adiponectin was significantly correlated with BAP (r: −0.413; P:0.003), OPG (r: 0.51; P<0.001), years since menopause (r: 0.295; P: 0.039), but was not with BMD in any site. Leptin was significantly related to weight (r: 0.41; P<0.01), BMI (r: 0.47; P<0.01) and waist (r: 0.38, P: 0.01), osteocalcin (r: 0.285; P: 0.038) and iPTH (r: 0.33; P: 0.016). Leptin was correlated with LS T score (r: −0.301; P: 0.04) and BMD LS (r: −0.266; P: 0.05) after adjustment for age and weight. After 12 months, no changes were observed in leptin (P: 0.46) and adiponectin (P: 0.55) in alendronate group; however, a significant increase in leptin levels (973.47±637.37 vs 1305.7±793.4 pM/ml; P: 0.031) was detected in the raloxifene group, whereas adiponectin levels showed no significant changes (P: 0.46). Moreover, the percentage changes of adiponectin levels did not differ between the two groups (P: 0.79); while the percentage changes in leptin levels were near significance, between the two groups (P: 0.07).

Conclusions: Adiponectin and leptin levels contribute at least in part to BMD in patients with postmenopausal osteoporosis. Changes in leptin levels after raloxifene treatment could be indirectly implicated in raloxifene bone effects.