Pleiotropic effects of PPARgamma agonists on bone remodeling

Peroxisome proliferator-activated receptor-gamma (PPARgamma) regulates both glucose and bone mass. PPARgamma activation has been shown to affect bone through an increased in bone marrow adiposity and decreased in osteoblastogenesis, resulting in reduced bone formation. In fact, clinical studies have reported that PPARgamma agonists may cause increased risk of bone fractures and decreased bone mineral density. On the other hand, PPARgamma agonists may have protective effect on inflammatory bone resorption through inhibition of RANKL- or TNFalpha-induced osteoclastogenesis. In this report, we review recent studies showing pleiotropic effects of PPARgamma agonists on bone formation and inflammatory bone resorption observed at joints in rheumatoid arthritis.