Bone Morphogenetic Protein Levels in Osteoarthritis

Abstract

Objective: The modern treatment approach for osteoarthritis aims at suppressing the inflammation by antagonizing such proinflammatory cytokines. More complicated approaches are expected to come to the forefront in the future that focus on such signals as bone morphogenetic proteins (BMPs) of the transforming growth factor (TGF)-beta superfamily and alleviate or antagonize the destruction process. These proteins are associated with many cellular functions, such as proliferation, differentiation, and apoptosis. We investigated the BMP levels in the serum and urine samples of patients with osteoarthritis. Material and Methods: A total of 41 patients with gonarthrosis, with grade 3 or 4 knees according to Kellgren-Lawrence Grading, and 50 healthy volunteers were included in the study. Visual analog scale was used for the assessment of pain. Levels of BMP7, BMP6, BMP4, and TGF-β1 were determined by ELISA method based on the serums obtained from the blood samples routinely taken from the patients as well as urine samples of 24 hours. Results: We evaluated the serum and urine samples of 37 patients with gonarthrosis and 29 healthy controls. There was no significant difference between the two groups with regard to age, weight, and height. Levels of serum TGFβ-1 and BMP6 were significantly higher in the patients compared to healthy controls (p=0.004, 0.002, respectively). As to urine samples, it was found that levels of TGFβ-1 and BMP7 were below the minimum detection limit proposed by the ELISA method in the patients. There was no statistically significant difference between the two groups with regard to levels of BMP4 and BMP6 in the urine (p>0.05). Conclusion: Levels of TGFβ-1 and BMP6 were higher in the patients compared to the controls. We think that more frequent examination of BMP levels in serum and urine samples, which are closely associated with the overall process of osteoarthritis, may guide future treatment studies.