STUDY OF SERUM OSTEOPROTEGERIN AND RECEPTOR ACTIVATOR OF NUCLEAR FACTOR KAPPA-Β LIGAND IN PATIENTS WITH RHEUMATIC DISEASES

Abstract

Although rheumatological diseases are widespread, they still have an unclear etiology, pathogenesis, and therapy. Researchers are looking for biomarkers associated with inflammatory and degenerative joint diseases. Serum Osteoprotegerin (s-OPG) and serum Receptor Activator of Nuclear Factor Kappa-Β Ligand (s-RANKL) have not been studied in patients with Diffuse idiopathic skeletal hyperostosis (DISH), spondylosis, ankylosing spondylitis, and gout. The aim of this study was to investigate s-OPG and s-RANKL in patients with various rheumatic diseases. Materials and methods: We studied 135 patients with rheumatic diseases, of which 55 were diagnosed with DISH, 50 with spondylosis, 23 with ankylosing spondylitis, 7 with gout, and 25 were a control group. s-OPG and s-RANKL, serum calcium, ionized calcium, serum phosphorus, alkaline phosphatase, uric acid, urea, creatine, and serum osteocalcin were tested using the ELISA method in the Clinical Laboratory of "St. George" University Hospital, Plovdiv. The results were processed using the statistical program SPSS ver 26, with significance p<0.05. Results: Patients with DISH and ankylosing spondylitis had higher levels of s-OPG, s-RANKL, and s-OPG/s-RANKL ratio than the control group (p<0.05). The s-OPG/s-RANKL ratio in patients with spondylosis and gout was lower than in patients with DISH and ankylosing spondylitis (p<0.05). There are strong correlations between s-OPG, s-RANKL, and the biochemical parameters related to bone metabolism (serum calcium, ionized calcium, serum phosphorus, alkaline phosphatase, uric acid, urea, creatine, and serum osteocalcin)(p <0.05). Conclusion: Our studies show that changes in bone metabolism are similar in patients with DISH and ankylosing spondylitis. Further research is needed to look for a common pathogenetic pathway linking degenerative and inflammatory rheumatic diseases of the axial skeleton.