New theory on neuro: our latest research round-up
August 03, 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 June 2016 and 21 July 2016. In each case, we have used the same name for the illness as the researchers publishing the paper.
New theory for the underlying mechanism in neurological conditions
An article in Molecular Neurobiology suggests that the underlying problem in chronic neurological conditions such as CFS might be due to a cell chemistry process called “hypernitrosylation.” The chemical nitric oxide is created when cells are damaged and plays a part in cell communication to regulate the immune system and alert our body to repair damage.
Nitric oxide itself can be harmful to cells, so the levels of this chemical are kept in check by a system called “nitrosylation,” where proteins mop up any excess to prevent further damage to cells. In chronic inflammation this safety mechanism is overwhelmed, leading to hypernitrosylation. After reviewing the literature on this subject the authors propose that hypernitrosylation leads to the problems found in CFS with autoimmunity, the autonomic nervous system, and the way mitochondria provide energy for cells.
Brain scans in teenagers with CFS
A study published by PLOS ONE compared the brain scans of teenagers with CFS and healthy controls of the same age. The scans revealed less activity in the salience network which links areas of the brain concerned with interpreting information. Less activity was found in the part of this network responsible for attention and alertness in the teenagers with CFS, which coincided with their high fatigue scores.
The activity in the part of the salience network responsible for dampening pain sensation was also lower, so this might explain an increased sensitivity to pain. These results have also been found in previous studies of adults with CFS and the authors conclude that the abnormal activity in these brain networks may contribute to CFS symptoms:
"These findings may also have broader implications for how abnormalities in fatigue and pain perception arise from a complex interplay among brain networks and stress-related alterations in chronic fatigue syndrome."
Muscle strain worsens symptoms in CFS
This study, also published by PLOS ONE, looked at the effects of a real and fake straight leg raising exercise for 15 minutes in CFS patients and controls. The CFS patients doing the real exercise experienced a significant increase in their fatigue, body pain, light-headedness, concentration difficulties, and headache scores during the exercises and at 24 hours afterwards. The authors suggest this is due to increased mechanical sensitivity in CFS.
Mast cells in moderate and severe CFS/M.E.
A study published in the Asian Pacific Journal of Allergy and Immunology compared mast cells (a type of white blood cell) in the blood of people with moderate and severe CFS/M.E. with those of healthy controls. Mast cells release histamine, cytokines, and other substances involved in allergic reactions and inflammation. Although this was a small study, it found significantly more of one type of mast cell present in the blood of the people with CFS/M.E.
In addition to this, the people with severe CFS/M.E. had many more immune system receptors on the surface of their mast cells compared with those with moderate CFS/M.E. and healthy controls. The authors suggest further investigation is needed to determine the role of mast cells in CFS/M.E. symptoms.
Blood volume in CFS
A study in Open Heart looked at blood volume in CFS patients and found that the volume of blood pumped by each heartbeat was much less than in the healthy controls, and that the total volume of blood in the bloodstream was also much lower. The thickness of the heart muscle wall during contraction was also less. Patients with more severe CFS had even lower blood volumes. The authors point out this must not be related to deconditioning, or being unfit due to being immobile, because the findings weren’t related to the length of time the patients have been ill:
"This study confirms an association between reduced cardiac volumes and blood volume in CFS. Lack of relationship between length of disease, cardiac and plasma volumes suggests findings are not secondary to deconditioning. The relationship between plasma volume and severity of fatigue symptoms suggests a potential therapeutic target in CFS."
Another study this month also looked at the hormones which control blood volume, this time in the Journal of Cardiology. The volume of blood in our bloodstream is partly regulated by the kidneys filtering fluid from our blood into urine. The amount of fluid retained is controlled by the renin-angiotensin and antidiuretic hormone systems. The study found that the levels of these hormones were much lower in CFS patients, meaning less fluid is retained, giving a lower blood volume. Half of the patients in this study responded well to desmopressin, which is a medicine that helps to increase blood volume by restricting the amount of urine produced.