Investigation of receptor activator of nuclear factor kappaB ligand and osteoprotegerin levels in multiple sclerosis patients

Aim: The aim of this study was to investigate the osteoprotegerin (OPG) and receptor activator of nuclear factor kappaB ligand (RANKL) levels and their correlation with bone mineral density (BMD) and levels of other bone turnover parameters such as serum osteocalcin, parathyroid hormone (PTH), calcium, bone alkaline phosphatase (bALP) and urinary deoxypyridinoline (DPD) in patients with multiple sclerosis (MS). Methods: Forty six MS patients (30F, 16M, 33.48 +/- 9.57 years old) and 24 healthy controls (14F, 10M, 33.04 +/- 7.97 years old) were included in the study. Serum OPG, RANKL, bALP, osteocalcin, PTH, calcium, urinary DPD levels of all subjects, and BMD of 29 patients and all control subjects were measured. Osteoprotegerin and RANKL levels, bALP, osteocalcin and PTH levels, and urinary DPD levels were measured by ELISA method, chemiluminescent method, and HPLC technique. The BMD was measured by dual-X-ray absorptiometry. Results: Serum OPG (p<0.01), RANKL (p<0.01), bALP (p<0.05), PTH (p<0.01) and calcium (p<0.05) levels were significantly higher in MS patients than in controls. There was no significant difference between serum osteocalcin, urinary DPD levels and BMD measures of the groups. Conclusion: Increased RANKL levels associated with osteoclastogenesis suggests a tendency towards osteoporosis in MS patients. However, no significant change in BMD levels of the subjects shows that the effect of RANKL is compensated by increased OPG levels. OPG and RANKL levels are involved in the pathogenesis and regulation of bone turnover and thus, circulating levels of them may be useful markers to assess bone turnover and to develop new approaches in MS.