Pattern of adipokine expression in osteoblasts from osteoporotic and osteoarthritic bone

Background & aims. Osteoarthritis (OA) and osteoporosis (OP) are the two most common osteo-articular diseases in elderly population, whose etiopathogenesis is complex and multifactorial. An inverse relationship between OA and OP has been observed and both diseases are characterized by apparently opposite changes in bone quantity and quality. In vitro studies revealed that osteoblasts from OA and OP bone present different phenotypes. Adipokines are involved in many physiological and pathological processes, including bone homeostasis and osteo-articular diseases. The aim of this study is to evaluate the expression of various adipokines in osteoblasts deriving from healthy subjects and patients suffering from OA or OP. Methods. Primary human osteoblast cultures were obtained from healthy, OA, and OP subjects. In each cell population the synthesis and gene expression of leptin, resistin and adiponectin were evaluated. Results. Adipokines showed an opposite patterns of adipokine expression in OA and OP osteoblasts. Leptin and resistin synthesis and expression were higher in OA osteoblasts compared to healthy and OP osteoblasts, while adiponectin synthesis and expression were significantly lower. Conversely, in OP osteoblasts a reduced synthesis and expression of leptin and resistin were observed, concurrently with increased adiponectin expression. Conclusions. These data confirm that osteoblasts deriving from OA and OP are characterized by different metabolic changes, consisting in opposite expression pattern of adipokines, and suggest that adipokines could be involved in the pathogenesis of bone alterations in both diseases.