Fibroblast growth factor-21 concentration in serum and synovial fluid is associated with radiographic bone loss of knee osteoarthritis

Abstract

We aimed to evaluate whether FGF-21 concentration in serum and synovial fluid (SF) is associated with radiographic bone loss of knee osteoarthritis (OA). A total of 186 OA patients and 108 controls were recruited. The radiographic bone loss of knee OA was assessed by the Ahlbäck grading scale. FGF-21 concentration in serum and SF was measured by enzyme-linked immunosorbent assay (ELISA). We demonstrated that OA patients had significantly higher serum FGF-21 concentration compared with controls (204.30 [range 158.25–279.16] ng/L vs. 130.72 [range 94.93–218.03] ng/L, p < 0.01). FGF-21 concentration in serum was well correlated with that in paired SF samples (r = 0.668, p < 0.001). In OA patients, those with a higher Ahlbäck grade had significantly higher serum and SF FGF-21 concentration (p < 0.001 for both). FGF-21 concentration in serum and SF was significantly and independently associated with the Ahlbäck grade (r = 0.403, p < 0.001 and r = 0.410, p < 0.001; respectively). These findings indicated that FGF-21 might be a potential biomarker for predicting bone loss of OA. Therapeutic interventions by blocking FGF-21 signaling pathways to delay the degenerative process of OA warrants further investigations.

Key Words::

• Adipokine
• fibroblast growth factor-21
• biomarker
• bone loss
• osteoarthritis

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.

This study was supported by the National Natural Science Foundation of China (grant no. 81370976 and 81400904) and the Shanghai Municipal Science and Technology Commission (grant 13ZR1424900).