Spinal Cord Injury Level and the Circulating Cytokine Response to Strenuous Exercise.

• Autores: Thomas A.w. Paulson, Nicolette C. Bishop, Victoria L. Goosey-Tolfrey, John P. Lenton, Christof Andreas Leicht
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 45, Nº. 9, 2013, págs. 1649-1655
• Idioma: inglés
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• Resumen

  • AB Purpose: A complete spinal cord injury (SCI) above the sixth thoracic vertebra (T6) results in the loss of sympathetic innervation of the adrenal medulla. This study examined the effect of a complete SCI above and below T6 on plasma concentrations of epinephrine, circulating interleukin 6 (IL-6) and other inflammatory cytokines in response to acute strenuous exercise. Methods: Twenty-six elite male wheelchair athletes (8 = C6-C7 tetraplegic [TETRA], 10 = T6-L1 paraplegic [PARA], and 8 = non-spinal-cord-injured controls [NON-SCI]) performed a submaximal exercise test followed by a graded exercise to exhaustion on a motorized treadmill. Blood samples were taken preexercise, postexercise, and 30 min postexercise and analyzed for concentrations of IL-6, IL-10, IL-1 receptor antagonist (IL-1ra), tumor necrosis factor [alpha] (TNF-[alpha]), epinephrine, and cortisol. Results: The circulating IL-6 concentration was significantly elevated at postexercise and 30 min postexercise (post30; approximately fivefold) in NON-SCI and PARA (P = 0.003), whereas concentrations in TETRA did not change significantly from preexercise values. IL-10, IL-1ra, and TNF-[alpha] were unaffected by exercise in all groups; however, both SCI groups presented elevated concentrations of IL-10 compared with NON-SCI (P = 0.001). At postexercise, epinephrine concentrations were significantly higher than preexercise and post30 concentrations in NON-SCI (approximately threefold) and PARA (approximately twofold) (P = 0.02). Plasma epinephrine concentrations were unchanged in TETRA throughout exercise; concentrations were significantly lower than NON-SCI and PARA at all time points. Plasma cortisol concentrations were significantly elevated in all groups at postexercise and post30 compared with preexercise (P < 0.001). Total exercise time was similar between groups (NON-SCI = 38 +/- 6; PARA = 35 +/- 5; TETRA = 36 +/- 5 min). Conclusions: These findings suggest that the sympathetic nervous system plays an important regulatory role in the circulating IL-6 response to exercise and has implications for the metabolic and inflammatory responses to exercise in individuals with injuries above T6.