Angiogenic cytokine expression profiles in plasma and synovial fluid of primary knee osteoarthritis

The aim of this study was to compare angiogenic cytokine levels in knee osteoarthritis (OA) patients and healthy controls and to investigate the relationships between angiogenic cytokines and the OA severity. Thirty-one knee OA patients and 15 healthy controls were recruited. Nine angiogenic cytokines (angiopoietin-2, follistatin, granulocyte-colony stimulating factor (G-CSF), hepatocyte growth factor (HGF), interleukin (IL)-8, leptin, platelet-derived growth factor-BB (PDGF-BB), platelet endothelial cell adhesion molecule (PECAM)-1, and vascular endothelial growth factor (VEGF)) in plasma and synovial fluid were measured using a multiplex immunoassay. PECAM-1, HGF, VEGF, angiopoietin-2, follistatin, G-CSF, and IL-8 concentrations in plasma were significantly higher in OA patients than those in controls. Plasma angiopoietin-2 was significantly greater in advanced OA than in early OA. Synovial fluid VEGF was positively correlated with the severity (r = 0.367, P = 0.04). Plasma follistatin was significantly lower in advanced knee OA than in early OA and was negatively correlated with the severity (r = -0.374, P < 0.05). Angiogenic cytokine concentrations in plasma can distinguish between controls and OA patients. Local and circulating levels of angiogenic cytokines could give an insight into the pathophysiology of OA. Follistatin, angiopoietin-2, and VEGF may have potential as biochemical markers for the assessment of OA severity.