Key Takeaways:
– Brain inflammation or neuroinflammation, often caused by chronic diseases, can result in muscle weakness.
– Recent findings reveal the existence of a brain-to-muscle communication pathway causing muscle fatigue.
– Targeting this pathway could offer new treatment strategies for muscle fatigue.
– Studies are underway to test neutralizing antibodies for muscle fatigue in mice.
– This promising research could benefit people suffering from diseases causing brain inflammation, like long COVID and Alzheimer’s.
Understanding Brain Inflammation and Muscle Weakness
Many people may not know that persistent or infectious illnesses such as long COVID, Alzheimer’s, or traumatic brain injury often cause inflammation in the brain. This inflammation, or neuroinflammation, can result in muscle weakness and fatigue. While medical professionals have recognized this connection, the molecules and processes involved remained a puzzle until recently.
Scientists and biologists came together and discovered the conversation between the brain and muscles that could hold the key to treating muscle fatigue. This exploration takes us into the world of neuroinflammation and how it results in muscle fatigue.
Neuroinflammation, the Culprit Behind Muscle Fatigue?
Neuroinflammation occurs when our central nervous system, comprising the brain and spine, jump-starts its immune system. This is usually to protect itself from potential harm, like infections, toxins, or injury. Mainly seen in the brain, these neuroinflammatory reactions often bring symptoms like fatigue and muscle pain outside the central nervous system.
To better understand this, scientists studied brain inflammation in the context of three different diseases. These include bacterial infection in E. coli-induced meningitis, viral infection in COVID-19, and neurodegeneration in Alzheimer’s disease. Next, they looked at how these immune variations affected muscle performance.
They observed that after stressing events like infection led to a buildup of toxic molecules in the brain, an overflow of cytokines followed. These are chemicals that activate the immune system and are sent out into the body. When these cytokines reach the muscles, they initiate a series of chemical reactions that hamper the ability of our muscle cells’ powerhouses – the mitochondria – to produce energy.
The Role of Brain-to-Muscle Communication
The accumulation of cytokines doesn’t seem to damage muscle fibers, but it does lead to fatigue. Analysis found that both mice and fruit flies moved significantly less in response to stimuli when their immune activation was offset by treatments. This suggested that these animals had reduced endurance.
The results point to the possibility that muscle fatigue following infection or chronic illness is the result of a brain-to-muscle communication pathway. This pathway drains energy from muscles without bothering their structure or integrity. In contrast to traditional assumptions for muscle dysfunction that focus on external issues such as muscle fiber damage, this pathway directly brings about fatigue.
The important cytokine in this brain-to-muscle communication has been conserved through evolution among different species, which suggests that this pathway could be the universal method the brain uses to lay claim to, and reallocate energy to combat infection.
A Broad Scope: Several Diseases Leading to Muscle Fatigue
Muscle weakness and fatigue often appear as symptoms in numerous diseases, these range from bacterial and viral infections to chronic diseases and neurodegeneration. These symptoms distress and lower the life quality of millions globally.
For instance, most of the 65 million people worldwide dealing with long COVID endure disabling fatigue that lasts from months to years. Similarly, loss of muscle strength is a common symptom of early stage Alzheimer’s disease, a condition that affects at least 50 million people globally.
Hope Afoot: Potential Treatments
This research suggests that targeting the brain-to-muscle axis could provide new treatment solutions for muscle fatigue. Presently, studies are being conducted on cultivating neutralizing antibodies in mice with neuroinflammation. These FDA-approved treatments specifically target brain cytokines and prevent signaling to the muscles.
Plans are also in the pipeline to profile cytokine levels in long COVID patients. It’s still unclear whether other proteins related to COVID-19 can also induce neuroinflammation and muscle fatigue. Despite these unknowns, the prospect of targeting the brain-muscle axis could be a lifesaver for those grappling with long COVID and other illnesses causing brain inflammation.