Effects of CGRP on human osteoclast-like cell formation: a possible connection with the bone loss in neurological disorders?

Osteoclast-like cell (OCL-like) differentiation is increased in long term cultures of bone marrow taken from paralyzed areas of paraplegic patients. Among the neuropeptides recently described in bone, calcitonin gene-related peptide (CGRP) has been shown in animal studies to inhibit bone resorption in vivo and OCL-like differentiation in vitro: its deficiency could thus be a link between the neural lesion and increased OCL-like production in paraplegia and some other neurologic disorders. We therefore investigated in this study the effects of CGRP on human OCL-like formation and found that it indeed has an inhibitory effect mediated at least in part via cAMP.