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ME/CFS Science

1) Dutch researchers compared muscle biopsies of ME/CFS and Long Covid patients to healthy participants who underwent 60 days of strict bed rest as part of a NASA study. A brief overview of how ME/CFS and LC differed from deconditioning...

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ME/CFS Science

2) While maximum oxygen uptake was similar, ME/CFS patients (in green) reached their Gas Exchange Threshold (GET) relatively sooner. GET is an indicator of switching to anaerobe energy production. So this could suggest that patients start producing lactate relatively sooner.

Ответ для ME/CFS Science
ME/CFS Science

3) While bed rest induced severe muscle atrophy, this was not seen in patients with long COVID or ME/CFS. In contrast to controls, patients atrophy seemed to be concentrated in one particular type of muscle fiber: type I or slow-twitch fibers used for endurance activities.

Ответ для ME/CFS Science
ME/CFS Science

4) In the bed rest participants, capillary density - the number of tiny blood vessels per area of muscle tissue - increased while in ME/CFS patients it decreased.

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ME/CFS Science

5) The authors also looked at markers of mitochondrial activity such as SDH (succinate dehydrogenase) and oxidative phosphorylation. These strongly correlated with VO2max in bed rest participants but not or much less so in ME/CFS or LC patients.

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ME/CFS Science

6) The authors write: "The lack of association of VO2max with mitochondrial variables suggests that their reduced exercise capacity is not solely explained by mitochondrial respiration or enzymatic activity."

Ответ для ME/CFS Science
ME/CFS Science

7) There were also some unexpected findings. The authors expected myoglobin (a protein that binds oxygen) to be increased in patients to compensate for a reduced local oxygen supply. But it was increased in bed rest participants, not in ME/CFS patients.

Ответ для ME/CFS Science
ME/CFS Science

8) ME/CFS patients exhibited a more pronounced increase in heart rate relative to oxygen uptake. There was a greater reliance on heart rate to satisfy a oxygen demand. This was a bit surprising because it often occurs in deconditioning (but not in this cohort of bed resters).

Ответ для ME/CFS Science
ME/CFS Science

9) A note on how to read the graphs: the left shows healthy people before (white) and after (gray) 60 days of bed rest. The right is a different cohort of healthy participants (white) that was matched to LC (orange) and ME/CFS (green) patients.

Ответ для ME/CFS Science
ME/CFS Science

10) The main limitations are the small sample size (only 26 ME/CFS participants) and that bed rest participants were not age and sex matched compared to the patient groups (the other healthy controls were). Link to the study: www.medrxiv.org/cont...

Skeletal muscle properties in long COVID and ME/CFS differ from those induced by bed restPatients with long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) suffer from a reduced exercise capacity, skeletal muscle abnormalities and post-exertional malaise (PEM), where symptoms worsen with cognitive or physical exertion. PEM often results in avoidance of physical activity, resulting in a lower aerobic fitness, which may contribute to skeletal muscle abnormalities. Here, we compared whole-body exercise responses and skeletal muscle adaptations after strict 60-day bed rest in healthy people with those in patients with long COVID and ME/CFS, and healthy age- and sex-matched controls. Bed rest altered the respiratory and cardiovascular responses to (sub)maximal exercise, while patients exhibited respiratory alterations only at submaximal exercise. Bed rest caused muscle atrophy, and the reduced oxidative phosphorylation related to reductions in maximal oxygen uptake. Patients with long COVID and ME/CFS did not have muscle atrophy, but had less capillaries and a more glycolytic fibers, none of which were associated with maximal oxygen uptake. While the whole-body aerobic capacity is similar following bed rest compared to patients, the skeletal muscle characteristics differed, suggesting that physical inactivity alone does not explain the lower exercise capacity in long COVID and ME/CFS ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was supported the Patient-Led Research Collaborative for Long COVID, the AMC and VU foundation, ZonMw Onderzoeksprogramma for ME/CVS, the Solve ME 2022 Ramsay Grant Program, ME Research UK, ME Stars of Tomorrow Scholarship award from the ICanCME Research Network (to B.T.C.), and Stichting Long COVID Nederland. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee of Amsterdam UMC, Medical Association North Rhine (number 2018143) and NASA (Johnson Space Center, Houston, United States) gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authorswww.medrxiv.org
Ответ для ME/CFS Science
ME/CFS research

If you look at the bed rest controls, the values for fiber%, capillary density and mitochondria respiration are similar to the patients, so it looks like the healthy controls were just different due to random variation. Seems like they have seriously misrepresented these results.

Ответ для ME/CFS Science
Susan K

Too bad the healthies in 60-day bedrest group (age 30, 66% men) are different from the healthies in comparator group (age 42, 50% men) It matters bc there are age & sex differences in muscle & performance variables e.g. fCSA change due to bedrest is greater in males (v females) bc they begin larger

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