Age-Related Changes of Chondrogenic Growth Factors in Platelet-Rich Plasma

Platelet-rich plasma (PRP) injections are a novel biological modality to promote tendon and ligament healing. PRP contains many growth factors that play critical roles in chondrogenesis, including insulin-like growth factor 1 (IGF-1), human growth hormone, transforming growth factor beta 1, basic fibroblast growth factor, and bone morphogenetic proteins 2, 4, and 7. Because articular cartilage degeneration is correlated with age, it is important to understand whether PRP contains sufficient levels of autologous growth factors across different age-groups for clinical applications in chondral regeneration or repair. PRP was isolated from 40 healthy volunteers between 20 and 60 years of age, and concentrations of bone morphogenetic proteins 2 and 4, basic fibroblast growth factor, human growth hormone, IGF-1, insulin-like growth factor-binding proteins 2 and 3, platelet-derived growth factor BB (PDGF-BB), transforming growth factor beta 1, and vascular endothelial growth factor were analyzed by enzyme-linked immunosorbent assay. Significant differences with respect to age were detected between subjects less than 30 and >30 years of age for PDGF-BB (P < 0.001), insulin-like growth factor-binding protein 3 (P < 0.001), and IGF-1 (P = 0.015). A significant difference was also detected between subjects <40 and >40 years of age for PDGF-BB (P = 0.015). Concentrations of other growth factors did not vary significantly across age-groups, suggesting that the molecular contents of therapeutic potential of PRP are similar for patients aged 20-60 years. Additional research is warranted to establish whether PRP may be beneficial for chondrogenesis in clinical practice and to determine the optimal mix of growth factors for orthopedic applications.