The response of IL-6 and its receptors to a standardised exercise challenge
Investigator
Professor MA Nimmo
Institution
Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
Aims
Although interleukin-6 (IL-6) has traditionally been considered a cytokine with immunomodulatory effects, there is evidence that it has a significant metabolic role and increases dramatically in response to exercise. For a variety of reasons, IL-6 may be a key candidate for investigation in ME/CFS patients whose observed fatigue could be associated with limitations in fuel utilisation and/or replenishment, in addition to the central effects. However, an understanding of the levels of IL-6 and its associated receptors is important before any functional consequences can be assessed. Exercise offers the opportunity to examine ME/CFS patients in an exacerbated state, yet many studies to date have not clearly categorised the exercise regimen. The limitations on continuing exercise are specific to the exercise type, with an incremental maximal test essentially being limited by cardiorespiratory fitness, whereas metabolic limitations may be more clearly identified through the use of a sub-maximal protocol as proposed in this research. An understanding of IL-6 and its associated receptors’ response to exercise could more clearly define any metabolic perturbance in these patients, and contribute to the development of a therapeutic drug intervention. For example, blockade of soluble IL-6 receptor by its natural antagonist has been shown to inhibit arthritis progression (Nowell et al, 2003), and a similar therapy may prove beneficial to those suffering from ME/CFS. The aim of this pilot study is to establish the response of IL-6 and its associated receptors during a submaximal exercise bout in ME/CFS patients and healthy controls over a 24-hour period. The findings may provide data forming the basis of a large programme of research on muscle and nerve function in people with ME/CFS.
Methods
This pilot study will involve 6 ME/CFS patients and 6 healthy control subjects matched for age and physical activity levels. The exercise will be undertaken at 90% lactate threshold, allowing a ‘matching’ of the metabolic load between controls and patients. Prior to attending the laboratory, all subjects will wear a heart rate monitor and note their activities in a diary for one week. All subjects will be required to visit the laboratory on 2 occasions, the first being for identification of the lactate threshold. On the second occasion, subjects will exercise at their identified exercise load in the morning after having taken a standardised liquid meal. Blood samples will then be taken pre and post-exercise and after 24 hours.
