Platelet-Derived Growth Factor as Biomarker of Clinical Outcome for Autologous Platelet Concentrate Therapy in Grade I Knee Osteoarthritis

Introduction: Autologous platelet concentrates (APC) are widely used in the infiltrative treatment of knee osteoarthritis (OA) to enhance tissue healing and relieve pain. Aim of this study was to identify predictive biomarkers for clinical outcomes in patients with grade I knee OA. Methods: A panel of growth factors (GFs) and cytokines was determined in peripheral blood (PB) and APC. The Numeric Pain Rating Scale (NPRS) was used as a clinical readout before and after the APC infiltration. Results: A lower white blood cell (WBC) count and higher Monocyte-chemoattractant Protein-1 levels in PB were associated with APC-induced pain relief. Platelet-derived Growth Factor (PDGF) levels in APC were significantly higher in OA patients displaying a larger NPRS reduction, independent of platelet count. Finally, the simultaneous determination of PDGF, Vascular Endothelial Growth Factor, and Macrophage Inflammatory Protein-1α in APC discriminated OA patients with very poor or no response. Conclusion: Platelet-released GFs rather than platelet counts may predict clinical outcomes in grade 1 knee OA.