Transforming Growth Factor Beta1 being considered a novel biomarker in knee osteoarthritis.

BACKGROUND: Associations between Transforming Growth Factor beta-1 (TGF-β1), Platelet-derived growth factor BB (PDGF-BB) and C-terminal telopeptide of type I collagen (CTX-1) with pathogenesis of osteoarthritis (OA) have already been established. Therefore, TGF-β1, PDGF-BB and CTX-1 could be used as the potential biomarkers for the diagnosis of this disease.

METHODS: 160 knee OA cases and 80 healthy controls were chosen. Serum concentrations of TGF-β1, PDGF-BB and CTX-1 were tested twice on the same samples using Enzyme-Linked Immunosorbent Assay. Knee OA cases were classified using Kellgren-Lawrence (K-L) criteria into four groups. Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index scores were evaluated for all cases.

RESULTS: TGF-β1 serum levels in knee OA cases were significantly higher compared to controls (t=11.37, p<0.01). Average serum level of TGF-β1 was positively associated with K-L grades. The diagnostic efficiency of serum TGF-β1 was proved to be moderate and the cut-point value was 12.11ng/ml showing favorable diagnostic indexes. In contrast, similarities were found not only in serum levels of PDGF-BB and CTX-1 between OA groups and controls but also in WOMAC scores.

CONCLUSION: Our findings supported that TGF-β1 has a positive correlation with the severity of knee OA confirmed by radiographs. Therefore, TGF-β1 might serve as a potential biomarker in established knee OA.