Impaired immune response to voluntary arm-crank ergometer exercise in patients with cervical spinal cord injury

Abstract

Study design: Non-randomized study. Objective: The mechanism underlying exercise-induced argumentation of natural killer cell cytotoxic activity (NKCA) in humans remains unclear. To address this, NKCA responses were studied during and after exercise in persons with cervical spinal cord injury (CSCI) and dysfunctional sympathetic nervous system. Setting: Kibikogen Rehabilitation Center for Employment Injuries. Methods: We examined the NKCA responses to 20-min arm-crank ergometer exercise at 60% of maximum oxygen consumption in eight persons with CSCI (between C6 and C7) and six able-bodied subjects. NKCA, adrenaline, and cortisol were measured before, immediately after exercise, 1 h after exercise, and 2 h after exercise. Results: In able-bodied subjects, NKCA increased immediately after exercise (Po0.01) and then decreased to below the pre-exercise level 1 h after exercise, before recovering to the baseline level at 2 h after exercise. Plasma adrenaline concentrations increased significantly immediately after exercise (Po0.01) and returned to the baseline level 1 h after exercise. The plasma cortisol level did not change throughout the study. In contrast, NKCA, plasma concentrations of adrenaline, and cortisol did not change throughout the study in subjects with CSCI. Conclusion: In subjects with CSCI, the lack of response in NKCA throughout the experiment is probably mainly due to a dysfunctional sympathetic nervous system.

Wheelchair half-marathon race increases natural killer cell activity in persons with cervical spinal cord injury

“…This deficit results in limitation of the peak heart rate in CSCI and often such subjects can neither complete intense exercise nor exercise longer than 20 min at 60% of VO 2 max, as demonstrated in our previous study. 7 Therefore, the subjects of the present study, that is, the wheelchair half marathon athletes with CSCI, who completed the race in about 80-110 min, are different to those who participated in our previous study. 7 In summary, the present study demonstrated that the wheelchair half-marathon race resulted in increase of NKCA despite the lack of increase in plasma adrenaline concentration in CSCI athletes.…”

“…7 Therefore, the subjects of the present study, that is, the wheelchair half marathon athletes with CSCI, who completed the race in about 80-110 min, are different to those who participated in our previous study. 7 In summary, the present study demonstrated that the wheelchair half-marathon race resulted in increase of NKCA despite the lack of increase in plasma adrenaline concentration in CSCI athletes. The intensity of the wheelchair half-marathon race activates NKCA in athletes with CSCI between C6 and C8, through mechanisms other than circulating adrenaline concentrations.…”

“…7 The difference between CSCI and AB was the pattern of plasma adrenaline, that is, exercise-induced increase in plasma adrenaline in AB but not in CSCI. 7 The CSCI athletes completed the wheelchair half-marathon race in about 80-110 min. The results of the present study suggest that such prolonged physical activity significantly increased NKCA even in CSCI.…”

“…6 In a previous study, we reported that 20-min arm exercise at 60% maximal oxygen consumption in CSCI did not increase NKCA, and such lack of response was probably mainly because of a dysfunctional sympathetic nervous system. 7 It is possible that both the number and activity of circulating NK cells in CSCI individuals fail to remain constant or even decrease during and after prolonged exercise, similar to the response to prolonged exercise in able-bodied (AB) persons. [8][9][10] Unfortunately, our CSCI subjects examined in our previous study could not perform prolonged arm-crank ergometer exercise (more than 20 min) at 60% of VO 2 max in the laboratory setting.…”

“…[8][9][10] Unfortunately, our CSCI subjects examined in our previous study could not perform prolonged arm-crank ergometer exercise (more than 20 min) at 60% of VO 2 max in the laboratory setting. 7 However, it is known that at least few CSCI individuals are able to complete wheelchair halfmarathon race and that a few international wheelchair sporting competitions hold half-marathon race for CSCI athletes.…”