Possible Regulation of bFGF Expression by Mast Cells in Osteoarthritis Patients with Obesity: A Cross-Sectional Study.

Purpose: Obesity is associated with the risk of developing knee osteoarthritis (KOA). Furthermore, synovial basic fibroblast growth factor (bFGF) is linked to the severity of KOA. We previously demonstrated that bFGF and mast cell (MC) marker expression were elevated in the synovial tissues (ST) of KOA patients with obesity. However, it remains unclear whether MCs contribute to bFGF expression and regulation.

Patients And Methods: Radiographically diagnosed KOA patients (n=249) were assigned to groups based on the body mass index (BMI) classifications used by the World Health Organization: normal-weight (NW, BMI <25 kg/m, n=95), overweight (OW, BMI ≥25 and <30, n=109) and obese (OB, ≥30 kg/m, n=45). expression in the ST was examined using quantitative polymerase chain reaction and compared across the BMI groups. Additionally, and ( expression were examined in freshly extracted MC-rich (THY-1-, CD3-, CD14-, and CD19-) and MC-poor (THY-1+, CD3+, CD14+, or CD19+) fractions from ST. Moreover, regulation of expression by IL-13 was studied in CD14-negative (fibroblast-rich) and CD14-positive (Mφ-rich) and cells in culture.

Results: expression was significantly higher in OB than in NW patients. Furthermore, although was significantly higher in the MC-rich than the MC-poor fraction, expression was comparable. Recombinant human IL-13 stimulated expression of in synovial fibroblast cells.

Conclusion: expression is higher in the ST of KOA patients with obesity. Increased numbers of MCs may contribute to the elevated expression through IL-13 in KOA patients with obesity.