Effect of transforming growth factor-beta on fibroblasts in ossification of the posterior longitudinal ligament.

We studied the immunohistochemical localization of TGF-beta in the ligament tissue of patients with ossification of the posterior longitudinal ligament (OPLL), and the effects of TGF-beta on cultured cells derived from the spinal ligament of patients with OPLL. ALP activity in the cultured cells was also examined. TGF-beta was present in the ossified matrix and in the chondrocytes in cartilaginous areas adjacent to OPLL. ALP activity was high in the cultured cells of OPLL patients. Exogenous TGF-beta inhibited proliferation in the OPLL cells but promoted proliferation in control cells. These results suggest that the spinal ligaments of OPLL patients have an osteogenetic predisposition and that TFG-beta may play a role in the ossification.