NTRK2 and osteosclerosis: Both BDNF and its receptor TrkB have been identified in fracture tissues during inflammation and early bone formation, primarily in endothelial and osteoblastic cells.72 BDNF was found specifically in granulation tissue at the margins of woven bone and was absent in chondrocytes and mature bone.72,74 Osteocytes displayed strong TrkB expression, and in an in vivo study with cortical osteotomy, BDNF was observed to boost osteosclerosis.