Brain changes and killer cells: research round-up
June 01, 2016
Each month, Action for M.E. Volunteer Pharmacist Emily Beardall explains some of the recently published research studies on M.E.
Please note this is not an exhaustive list – we have selected to highlight the studies that we think are most likely to resonate with the daily lives of those affected by the condition. We will also report separately on further studies of significance, as and when they are published.
You can search online directory PubMed for most studies about M.E. published in peer-reviewed journals.
The following studies were published online between 22 April and 21 May 2016. In each case, we have used the same name for the illness as the researchers publishing the paper.
Brain changes in CFS over time
A study in the Journal of Magnetic Resonance Imaging aimed to discover whether there are brain changes in CFS patients over time. The MRI scans of a group of CFS patients and a healthy controls were examined, and then again six years later. While there was no change in the scans of the healthy controls, a decrease in the volume of brain matter and blood supply was found over time in CFS patients, in a part of the brain which links regions responsible for cognitive functioning. This corresponded with the impaired concentration, working memory loss, inability to focus vision, and poor motor coordination of those with CFS.
Natural killer cells in M.E./CFS
Natural killer cells, part of the immune system, are a type of white blood cell which destroys cells infected with viruses. This study in the Application of Clinical Genetics compared the activity and genetics of natural killer cells from people with M.E./CFS and healthy controls. The natural killer cells of those with M.E./CFS were found to be less effective at destroying virus-infected cells than in the healthy controls. Sixteen differences in gene coding for cell receptors involved in control of the autonomic nervous system and chronic pain were also found. The authors suggest that these natural killer cell differences in M.E./CFS could contribute to the underlying pathology of the illness.
An additional study in the Journal of Translational Medicine looks in more detail at why the natural killer cells of people with CFS/M.E. are less effective. It was found that a cascade of reactions called MAPK signalling pathways inside the natural killer cells is working incorrectly in CFS/M.E. patients. These pathways control functions such as the division, movement, and survival of natural killer cells. The researchers recommend a larger study looking at the clinical subgroups of CFS/M.E. to confirm this cause of reduced natural killer cell activity.
Predicting those at risk of post-infectious CFS
Many of the biomarkers now being used in research aren’t practical for use clinically because they require highly specialised techniques. A study in BMC Pediatrics found that a combination of more easily obtained blood, salivary and urine test results could be linked with the development of post-viral fatigue following infectious mononucleosis (Epstein-Barr virus). Although the findings need to be replicated on a larger scale, the authors hope that this combination of tests could be used to predict which patients are most likely to develop long-term post-viral fatigue after this common childhood viral infection (95% of people have had EBV, but only a few go on to get post-viral fatigue). This could inform earlier treatment and advice for those at risk.
Long-term high exercise levels do not lead to post-viral fatigue
A study in the Journal of Brain Behaviour Science looked at high levels of exercise at the time of infection as a possible factor determining whether Epstein-Barr virus develops into the prolonged physiological sickness response seen in CFS. Although the study involved mice rather than humans, it was found that a high level of exercise was neither protective nor harmful when combined with repeated exposure to the virus.
Relationship between age and illness duration
A study published in Diagnostics used information collected about people with CFS and found that age and illness duration are important factors when it comes to functioning and symptom severity. Regardless of duration of illness, people under 55 had worse symptom scores than older patients, along with worse mental health as a result. Those who were older and had lived with the illness for more than 10 years had much better mental health. The authors recommend that more support should be provided for younger people with CFS to help cope with the devastating impact of the illness.
Differences in hormones controlling the nervous system
Another study in the Journal of Translational Medicine examined the hormones affecting control of the autonomic nervous system in teenagers with CFS. The blood levels of nine hormones were taken, symptoms were charted, and daily physical activity was recorded. Higher levels of adrenaline and noradrenaline were found, which regulate the sympathetic nervous system’s fight or flight response, along with differences in ratios of other hormones, such as cortisol, creatinine and thyroxine. The authors concluded that differences in levels and ratios of the hormones in CFS patients point towards a different mechanism of neuroendocrine control from that seen in healthy controls.