Submitted to: Annals of the New York Academy of Sciences
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/23/2009
Publication Date: 3/15/2010
Publication URL: http://handle.nal.usda.gov/10113/46215
Citation: Cao, J.J., Sun, L., Gao, H. 2010. Diet-induced Obesity Alters Bone Remodeling Leading to Decreased Femoral Trabecular Bone Mass in Mice. Annals of the New York Academy of Sciences. 1192:292-297. Interpretive Summary: Obesity is a major risk factor for many health disorders mainly because of its associated chronic low-grade inflammation. Studies have shown that obesity (or excessive fat accumulation) is detrimental to bone and is associated with osteoporosis development. To further investigate the effects of high-fat diet on bones at different sites and the mechanisms through which obesity affects bone metabolism, we evaluated bone microarchitecture of distal femur by micro computed tomography, measured serum cytokines related to bone metabolism, and measured osteoclast formation in bone marrow cells in a diet-induced obese mouse model. In conclusion, our results show that obesity induced by a high-fat diet decreases femoral trabecular bone mass by increasing trabecular separation and reducing trabecular number and connectivity density in young mice. Obesity induced by a high-fat diet may alter the bone remodeling by favoring resorption that blunts any positive effects of increased body weight on bone formation.
Technical Abstract: Body mass derived from an obesity condition may be detrimental to bone health but the mechanism is unknown. This study was to examine changes in bone structure and serum cytokines related to bone metabolism in obese mice induced by a high-fat diet(HFD). Mice fed the HFD were obese and had higher serum tartrate-resistant acid phosphatase (TRAP) and leptin but lower osteocalcin concentrations than those fed the normal-fat diet. The HFD increased multinucleated TRAP positive osteoclasts in bone marrow compared to the control diet. Despite being much heavier, mice fed the HFD had lower femoral bone volume, trabecular number, and connectivity density while had higher trabecular separation than mice on the control diet. These findings suggest that obesity induced by high-fat diet may alter the balance of bone remodeling process by favoring resorptive process that mitigates the positive effect of increased body weight on bone formation.