Evaluation of Vitamin D Receptor in Subsynovial Connective Tissue of Carpal Tunnel Syndrome

Abstract

Introduction : Studies suggest that the pathophysiology of carpal tunnel syndrome (CTS) is associated with pathologic changes in the vascularity and physical properties of the subsynovial connective tissue (SSCT) in the carpal tunnel. Aside from its classic action in musculoskeletal system, broad range of roles of vitamin D has been reported, including anti-inflammatory, anti-cancer, neuroprotective role and even cardiovascular benefits. In this study we aimed to evaluate whether vitamin D receptor (VDR) is present in the SSCT endothelial cells in patients with CTS, and whether its expression is associated with clinical features of CTS.

Patients & Methods : During open carpal tunnel release, specimens of SSCT from 54 patients with CTS were obtained, and stained for VDR in the SSCT endothelial cells using immnunohistochemistry. We evaluated correlation of VDR expression with clinical variables such as serum vitamin D level, age, body mass index and symptom duration, electrophysiologic severity in terms of motor conduction velocity and distal motor latency.

Results : Diverse expression of VDR was observed in endothelial vessels of SSCT. VDR expression was found to be significantly correlated with age, symptom duration, and distal motor latency, but not with other variables.

Discussion : This study found that VDR exists in the endothelial cells of the SSCT in patients with CTS. The association of a higher VDR expression with age, symptom duration, and electrophysiologic severity of the disease suggests that VDR may be up-regulated and contribute to disease progression by provoking angiogenesis. Further studies are necessary to confirm the role of vitamin D and VDR in patients with CTS, and to determine whether vitamin D supplementation could be helpful for prevention and treatment of CTS.