This study examining the effect of age and sex on PRP cytokine composition in healthy, asymptomatic humans showed significantly higher cytokine and growth factor levels in males compared with females, although the growth factor IGF-1 showed higher levels in younger subjects versus older subjects.
Platelet-rich plasma (PRP) is widely used for multiple clinical applications to promote healing and decrease inflammation. The effect of age and sex on PRP composition is not well described and could affect treatment efficacy, and prior biologics research on mesenchymal stem cells has shown that growth potential is modulated by age and sex. In particular, the composition of inflammatory cytokines such as Il-1b and TNF-alpha could affect inflammatory and pain response in response to PRP treatment. Furthermore, variance in the composition of growth factors, particularly those that are linked to platelet release such as platelet-derived growth factor (PDGF), transforming growth factor ß-1 (TGF- ß1), and insulin-like growth factor 1 (IGF-1), could also affect treatment and potential regenerative response. This study was performed to test the hypotheses that the biochemical composition of human PRP differs by sex and age.
38 healthy, asymptomatic individuals with no history of orthopaedic injury, and a body mass index = 30 kg/m^2 donated blood that was processed into leukocyte poor PRP using a standardized laboratory protocol. Twenty subjects were ages 18-30 (10 males, 11 females) and 18 subjects were ages 45-60 (8 males, 10 females). Cytokine and growth factor levels were assessed by Multiplex assay and ELISA. Platelet count and high sensitivity c-reactive protein were determined by the clinical laboratory.
Males had significantly higher cytokine and growth factor levels compared to females, including inflammatory cytokines such as Il-1beta (9.82-7.706 pg/mL, p=0.0049), TNF-alpha (131.6 versus 110.5 pg/mL, p=0.03), the anti-inflammatory Il-1ra (298.0 versus 218.1 pg/mL, p=0.0005), as well as growth factors such as FGF-basic (237.9 versus 194.0 pg/mL, p=0.005), PDGF-bb (3296.2 versus 2579.3 pg/mL, p=0.03), VEGF (142.5 versus 108.5 pg/mL, p=0.03), and TGF- ß1 (118.8 versus 92.8 ng/mL, p = 0.002). IGF-1, on the other hand, showed significantly higher levels in the younger cohort compared to the older cohort (97.6 versus 53.8 pg/mL, p < 0.0001) but no significant sex-related differences. No correlations were observed between enhanced CRP and cytokine levels.
This study examining the effect of age and sex on PRP composition in healthy, asymptomatic humans showed differences in cytokine and growth factor levels between males and females. Most cytokines and growth factors showed significantly higher levels in males compared with females, although the growth factor IGF-1 showed higher levels in younger subjects versus older subjects.
These findings suggest that men and women may respond differently to PRP treatment. Further evaluation of the impact of age, sex, and disease states are needed to inform clinical use of PRP.