Genetic Expression After Exercise in Fibromyalgia & Chronic Fatigue Syndrome

Posted on Jul 20, 2011 in Chronic Disease, Health & Wellness

By Adrienne Dellwo

Researchers behind a new study say they’ve discovered post-exercise differences in genetic expression that meet criteria for an objective biomarker for a subgroup of chronic fatigue syndrome (ME/CFS). They also say data show two distinct subgroups of ME/CFS and also differentiate fibromyalgia (FMS) from both ME/CFS and healthy controls.

Researchers analyzed blood samples before exercise to get a baseline, then took samples again half an hour, 8 hours, 24 hours and 48 hours after moderate exercise (maintaining maximum heart rate for 20 minutes.) They were looking for changes in genes that deal with sensory fatigue and muscle pain, which are common post-exercise symptoms of ME/CFS. The found that:

• 71% of the ME/CFS group (34 of 48) had increased expression of 4 genes dealing with sensory and adrenergic receptors and cytokines for 48 hours after exercise;
• Those with the largest change in genetic expression also had the largest increase in post-exercise symptoms;
• The other 29% of the ME/CFS group (14 of 48) did not show the above changes but did have a decrease in expression of the adrenergic α-2A receptor;
• This group had significantly more orthostatic intolerance (dizziness upon standing) than the first group;
• Healthy controls and people with FMS had no post-exercises changes in the genes that were studied;
• However, those with FMS had baseline elevations in 3 genes — 2 sensory ion channels and 1 cytokine — that were not found in the other groups.

These differences in genetic expression could help explain post-exertional malaise (PEM), which is considered the hallmark symptom of ME/CFS. PEM causes a marked upswing in symptoms after exertion, and for some people it takes very little exertion — such as taking a shower or walking to the mailbox — to trigger this symptom. In the most severe cases, even sitting up for a few minutes can lead to PEM.

FMS involves a similar but generally less-severe reaction to over exertion or stressful events, and these genetic abnormalities could help shed light on this as well.

Researchers concluded that these findings could help establish an objective biomarker for diagnosing at least 1 subgroup of ME/CFS, guide treatment for both identified ME/CFS subgroups, and differentiate FMS from ME/CFS.