The effect of simvastatin on serum cytokine levels and bone metabolism in postmenopausal subjects: negative correlation between TNF-alpha and anabolic bone parameters.

In this prospective study, we aimed to evaluate the effect of simvastatin on bone metabolism and the correlation between changes in bone turnover parameters and serum cytokine levels. For this purpose, 38 postmenopausal subjects with hypercholesterolemia (>240 mg/dl), not on osteoporosis treatment, were studied. Simvastatin was started at a dose of 20 mg daily and continued for 3 months. Six patients were excluded from the study during the follow-up period. Pre- and post-treatment samples were analyzed for bone alkaline phosphatase (BAP) and osteocalcin (OCL), as markers of bone formation; for carboxyterminal telopeptide of collagen I (CTX), as a marker of bone resorption; and for interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) cytokine levels. Total cholesterol level was decreased from 262.1 +/- 30.9 to 210.2 +/- 35.6 mg/dl after simvastatin treatment (P < 0.0001). While no significant change was observed in serum CTX level, BAP and OCL levels were significantly increased (from 120.8 +/- 56.6 to 149.5 +/- 57.6 IU/l [P = 0.008], and from 20.8 +/- 12.6 to 34.7 +/- 18.4 microg/l [P = 0.015], respectively). In the analysis of cytokines, while no significant change was observed in IL-6 levels, the TNF-alpha level was found to be significantly decreased after simvastatin treatment (from 77.9 +/- 31.6 pg/ml to 23.5 +/- 12.6 pg/ml [P = 0.021]). Individual changes in TNF-alpha levels showed a moderate negative correlation with the individual changes in BAP and OCL levels (r = -0.550 [P = 0.001], and r = -0.497 [P = 0.004], respectively). In conclusion; 20-mg daily simvastatin treatment for 3 months significantly increased BAP and OCL levels (markers of bone formation) in hypercholesterolemic postmenopausal subjects, without affecting bone resorption. These findings support the idea that simvastatin has an anabolic effect on bone formation. Additionally, the presence of a negative correlation between TNF-alpha levels and the anabolic bone parameters suggests that a cytokine-lowering effect of simvastatin may also be involved in the remodeling process and could exert some additive beneficial effect on bone metabolism.