RESUMO
OBJECTIVE: Platelet-rich plasma has potential uses for patients with spinal cord injuries. However, no study has quantified the cellular and growth factor content of platelet-rich plasma in this population. This study aimed to analyze (1) platelet-rich plasma content of spinal cord injury subjects and (2) the effect of high-intensity interval exercise on their platelet-rich plasma. DESIGN: Ten spinal cord injury patients and 10 controls were enrolled. At rest, platelet-rich plasma was created from both groups. The spinal cord injury group then performed high-intensity interval exercise and underwent a second blood draw to create post-high-intensity interval exercise platelet-rich plasma. Complete blood counts and growth factor analysis (via enzyme-linked immunosorbent assay) was performed on all platelet-rich plasma. RESULTS: The spinal cord injury group had lower platelets (305,700 ± 85,697/µl vs 380,800 ± 57,301/µl, P = 0.015) and transforming growth factor ß (12.84 ± 1.58 vs 14.33 ± 0.63 ng/ml, P = 0.023). Four minutes of high-intensity interval exercise increased the platelets (305,700 ± 85,697/µl to 399,200 ± 96,251/µl, P = 0.004), leukocytes (906 ± 930 vs 2504 ± 3765/µl, P = 0.002) and transforming growth factor ß (12.84 ± 1.58 to 14.28 ± 1.21 ng/ml, P = 0.020). CONCLUSIONS: Spinal cord injury patients have fewer platelets and transforming growth factor ß in their platelet-rich plasma at baseline compared with controls. Exercise increased platelet, leukocyte, and transforming growth factor ß yield, compensating for the baseline deficits.