Calcitonin gene-related peptide is potential therapeutic target of osteoporosis

Osteoporosis is a skeletal disorder characterised by the decrease of bone mineral density and is becoming prevalent with the entry of an ageing era. There are two catalogues of osteoporosis, including primary osteoporosis and secondary osteoporosis, according to the pathological causes. Since the demonstrations of osteoporosis are usually covered by other diseases, its therapeutic strategies are not satisfactory for both patients and clinicians. Calcitonin gene-related peptide (CGRP) is a peptide expressed in both bone tissues and peripheral nerves innervating bone tissue, and its expression in osteoporosis patients is increased. Recent studies have indicated that CGRP could promote the osteogenesis by osteblasts and bone absorption by osteoclasts, thus maintaining the bone homeostasis. The effects of CGRP on bone homeostasis are related with its promotion of angiogenesis through vascular endothelial growth factor and its modulation of multiple signal pathways including receptor activator of nuclear factor kappa-. ligand. In addition, CGRP could interact with neuronal system through neural growth factor to modulate osteoporosis. Application of implants or nanoparticles also verified the beneficial effect of CGRP on osteoporosis. There studies imply a great therapeutic potential of CGRP in treating osteoporosis. Although massive studies about CGRP in osteoporosis have been performed with positive results, there is little development in clinical application. The review summarises recent advancement in the roles of CGRP in modulating osteoporosis, which will be helpful in providing some directions for further study of CGRP in treating osteoporosis.