T10c12 CLA isomer prevents age associated bone loss by modulating osteoclastogenesis

Abstract

Osteoporosis is one of the major causes of morbidity in the elderly. Inflammation exerts a significant influence on bone turnover, inducing the chronic form of osteoporosis. Dietary nutrition has the capacity to modulate inflammatory response. Therefore, nutritional strategies and lifestyle changes may prevent age‐related osteoporosis, thereby improving the quality of life of the elderly population. Conjugated linoleic acid (CLA) has been shown to positively influence calcium and bone metabolism. Earlier we have shown that CLA (equal ratio of c9t11 and t10c12 isomers) can protect age associated bone loss by modulating inflammatory markers and osteoclastogenesis. However, c9t11 and t10c12 CLA individual isomers differentially regulate functional parameters and gene expression in different cell types. Therefore, the present study was undertaken to examine the differential effect of c9t11 and t10c12 CLA isomers on bone mineral density (BMD) in middle‐aged (12 mo) C57BL/6 female mice. After 5 months on diet, t10c12 CLA‐isomer fed mice maintained a significantly higher BMD in femoral, tibial and lumbar regions than c9t11 and corn oil (CO)‐fed mice. The increased BMD was accompanied by a decreased activity of osteoclastogenic factor, RANKL and decreased osteoclast activity as measured by TRAP5b in serum. A significant reduction of osteoclasts differentiation was also observed in RANKL stimulated RAW 264.7 cells in t10c12 CLA isomer treated culture as compared to c9t11 CLA isomer or linoleic acid treated culture. In conclusion, these findings suggest that t10c12 isomer is the most potent CLA isomer to prevent the bone loss by modulating osteoclastogenesis. Research support: NIH R21 AG027562.