A new study reveals how brain inflammation from infections and neurodegenerative diseases causes muscle weakness by releasing the IL-6 protein. Researchers found that IL-6 travels from the brain to muscles, reducing their energy production and function.
NeuroScience via Washington University School of Medicine in St. Louis (WUSTL)
Extracts
Infections and neurodegenerative diseases cause inflammation in the brain. But, for unknown reasons, patients with brain inflammation often develop muscle problems that seem to be independent of the central nervous system.
Now, researchers at Washington University School of Medicine in St. Louis have revealed how brain inflammation releases a specific protein that travels from the brain to the muscles and causes a loss of muscle function.
The study, in fruit flies and mice, also identified ways to block this process, which could have implications for treating or preventing the muscle wasting sometimes associated with inflammatory diseases, including bacterial infections, Alzheimer’s disease and Long Covid.
The study is published July 12 in the journal Science Immunology.
We are interested in understanding the very deep muscle fatigue that is associated with some common illnesses. Our study suggests that when we get sick, messenger proteins from the brain travel through the bloodstream and reduce energy levels in skeletal muscle. This is more than a lack of motivation to move because we don’t feel well. These processes reduce energy levels in skeletal muscle, decreasing the capacity to move and function normally.
Senior Author Aaron Johnson, PhD, an associate professor of developmental biology
The study pinpoints potential targets for preventing or treating muscle weakness related to brain inflammation. The researchers found that IL-6 activates what is called the JAK-STAT pathway in muscle, and this is what causes the reduced energy production of mitochondria.
In the meantime, we hope our study encourages more clinical research into this pathway and whether existing treatments that block various parts of it can help the many patients who experience this type of debilitating muscle fatigue.
Senior Author Aaron Johnson, PhD, an associate professor of developmental biology
MEA Comment
This is a report on some interesting animal model research from America, which has used an animal model to create a possible sequence of events that explains how a viral infection can cause debilitating fatigue in Long Covid.
There is nothing really new here because the immune system chemical involved has also been implicated as the cause of fatigue in ME/CFS.
In very simple terms the sequence of events involves a viral infection (Covid 19 in this case) causing inflammation in the central nervous system.
This results in the immune system producing a chemical (cytokine) called interleukin 6 which reduces how energy is produced by cellular structures called mitochondria.
If this is the case then it opens the door to assessing the use of drugs which can reduce the level of interleukin 6.
Dr Charles Shepherd,
Trustee and Hon. Medical Adviser to the ME Association,
Member of the 2018-2021 NICE guideline on ME/CFS committee,
Member of the 2002 Chief Medical Officer's Working Group on ME/CFS
Further Coverage
Technology Networks: Brain Inflammation Study Reveals Pathways To Combat Muscle Fatigue in Long COVID and Alzheimer's | 15th July 2024
Science Alert: We May Have Found a Target For Treating The Fatigue of Long COVID | 29th July 2024