Report

Spinal cord injury level and the circulating cytokine response to strenuous exercise

Assessing the circulating cytokine response to strenuous exercise in varying SCI levels.

Lead academic:
Professor Vicky Tolfrey
Additional academics:
Dr Christof Leicht
Funder:
The Peter Harrison Foundation

The effect of the resulting decreased sympathetic outflow in individuals with tetraplegia includes depressed circulating adrenaline and noradrenaline plasma concentrations at rest, during and after exercise.

If the sympathetic nervous system (SNS) only plays a minor role in the IL-6 (an inflammation mediating cytokine) response to exercise, then individuals with complete injuries above T6 would be expected to demonstrate similar elevations in circulating IL-6 concentrations after exercise to those observed in individuals with an intact SNS (i.e. who are injured at or below T6, or who do not have a SCI). However, if this is not the case, a limited IL-6 response in those with injuries above T6 could have important health implications given the proposed metabolic and inflammatory roles of muscle-derived IL-6 in a population with already limited physical capacity.#

Methods

  • 26 elite male wheelchair athletes (8 individuals with C6-C7 tetraplegia (TETRA); 10 with T6-L1 paraplegia (PARA); and 8 non-spinal cord injured controls (NON-SCI)) performed a submaximal exercise test followed by a graded exercise to exhaustion test on a motorised treadmill. Blood samples were taken pre-exercise, post-exercise and 30 min post-exercise (post30) and analysed for concentrations of IL-6, IL-10, IL-1 receptor-antagonist (IL-1ra), tumor necrosis factor-alpha (TNF-α), adrenaline and cortisol.

Main findings and applications

  • This study suggests the SNS plays an important regulatory role in the circulating IL-6 response to exercise.
  • Our findings support a role for the SNS as an important modulator of the release and/or synthesis of IL-6 from contracting skeletal muscle.
  • This has important health implications for individuals with a cervical SCI as exercise-induced elevations in plasma IL-6 have previously been related to the creation of an anti-inflammatory environment in the hours post-exercise. This in turn has been associated with a reduction in the risk of developing cardiovascular disease, a major cause of mortality in those with a SCI.

Reference

Paulson, T., Goosey-Tolfrey, V., Lenton, J., Leicht, C. and Bishop, N. (2013). Spinal cord injury level and the circulating cytokine response to strenuous exercise. Medicine and Science in Sports and Exercise. 45(9): 1649-1655. DOI: 10.1249