Myelin Damage May Be the Silent Culprit Behind Memory Loss in Aging and Neurological Illnesses
Nikhil Prasad Fact checked by:Thailand Medical News Team Jun 18, 2025 2 weeks, 6 days, 8 hours, 53 minutes ago
Medical News: In a groundbreaking medical review, researchers from the Institute for Cerebrovascular and Neuroregeneration Research (ICNR) and the Department of Pharmacology, Toxicology, and Neuroscience at Louisiana State University Health Sciences Center in Shreveport, Louisiana, have revealed that a common and often overlooked biological process may be playing a major role in aging and brain disorders—myelin dysfunction.
Myelin dysfunction in aging and brain disorders. The schematic illustrates myelin dysfunction in the aging brain and various brain disorders. These conditions often involve demyelination, hypomyelination caused by reduced new myelin formation, or a combination of both. Such myelin dysfunction may underlie the neurological symptoms commonly observed in these medical conditions
Myelin is a protective, fatty sheath that wraps around nerve fibers in the brain and spinal cord. It helps neurons transmit electrical signals efficiently and also provides vital metabolic support to axons. But when myelin is damaged, brain function can spiral. This
Medical News report explores how faulty myelin might be a root cause in everything from memory problems and depression to stroke, Alzheimer’s disease, and even complications from COVID-19.
What Is Myelin and Why It Matters
Myelin acts like insulation for the brain’s electrical wiring. It speeds up communication between nerve cells and helps protect the structural integrity of neurons. While most of it is built during early life, new research shows that myelin also continues to form in response to life experiences—a process known as adaptive myelination. Activities such as learning new skills or even social interactions can increase myelin formation, supporting memory and mental health.
Animal studies confirm that reducing myelin leads to memory problems and mood disorders. Conversely, boosting myelin production can reverse these effects, underlining how essential this process is to brain function.
How Myelin Deteriorates with Age
As people age, studies using high-resolution imaging and brain autopsies have documented a steady loss of myelin in key brain areas responsible for memory and learning. This degeneration is often seen even in people with no signs of dementia. The researchers discovered that in aged mice, both the production of new myelin and the quality of existing myelin declined dramatically. Internodes—segments of the myelin sheath—become shorter, and debris from broken myelin accumulates.
Interestingly, when scientists treated older mice with clemastine fumarate, a common antihistamine drug known to support myelin repair, they observed a reversal of memory decline. This suggests that myelin restoration could potentially treat age-related cognitive impairment.
Myelin and Alzheimer’s Disease
Perhaps even more shocking is the link between myelin dysfunction and Alzheimer’s disease (AD). Traditionally seen as a condition caused b
y amyloid plaques and tau tangles, AD is now increasingly associated with myelin damage. In several animal models, myelin loss actually occurs before the build-up of plaques and cognitive decline.
Postmortem studies of human brains with AD show significant loss of myelin in regions responsible for learning and memory. Genetic factors also play a role. The APOE4 gene, which raises Alzheimer’s risk, has been shown to disrupt cholesterol processing in the brain, leading to thinner and weaker myelin. Pharmacological treatments that improve cholesterol transport in APOE4 mice enhanced memory and boosted myelin levels—offering a potential new treatment pathway.
Depression and Schizophrenia Also Linked to Myelin
The review also explored how mood and psychiatric disorders might have a common biological root. Individuals with depression and schizophrenia consistently show reduced levels of myelin in brain scans and postmortem tissue samples. In depressed mice, chronic stress led to the breakdown of myelin in brain regions responsible for mood regulation.
Moreover, pharmacological treatments like clemastine fumarate were found to improve behavior in animal models by enhancing myelin repair. Even ketamine—known for its rapid antidepressant effects—was shown to increase myelin levels in the hippocampus and prefrontal cortex, offering a new explanation for how it may work at the cellular level.
In schizophrenia, both human and animal studies reveal widespread reductions in myelin and myelin-producing cells. Poor brain connectivity, a hallmark of schizophrenia, could thus be directly tied to disrupted myelination.
Myelin Damage in Stroke and COVID-19
Stroke survivors often face long-term mental and physical deficits. New findings reveal that myelin damage extends far beyond the initial area of the brain affected by stroke, sometimes appearing in regions not directly impacted by the loss of blood flow. Inflammatory processes and cholesterol disruptions may be key drivers of this widespread damage.
Strikingly, neurological symptoms seen in Long COVID—such as brain fog, fatigue, and cognitive issues—are also being connected to compromised myelin integrity. The virus, inflammatory responses, or vascular damage may all play a role in triggering demyelination during or after SARS-CoV-2 infection.
Promising New Drugs to Repair Myelin
With myelin dysfunction appearing across so many diseases, scientists are now focusing on ways to repair or regenerate this critical structure. The researchers identified several promising drug candidates that may promote remyelination:
-Benztropine and clemastine fumarate: These FDA-approved medications stimulate myelin repair by blocking muscarinic acetylcholine receptors.
-PIPE-307: A novel compound that boosts myelin repair in both animal and human brain tissue.
-Miconazole and clobetasol: Originally antifungal and corticosteroid drugs, respectively, they trigger remyelination via specific signaling pathways.
-Bazedoxifene: A selective estrogen receptor modulator that acts independently of hormone receptors to promote myelination.
-ESI1: An epigenetic modulator that reverses the silencing of myelin-related genes, improving both myelin structure and cognitive function.
Some of these agents, like clemastine fumarate, have already shown encouraging results in human trials, including improvements in visual nerve function in patients with multiple sclerosis.
Conclusion
The emerging science surrounding myelin is reshaping our understanding of brain health. What was once thought of merely as insulation is now recognized as a vital player in learning, memory, emotion, and recovery from brain injury. Myelin dysfunction appears to be a common factor in aging, stroke, depression, schizophrenia, Alzheimer’s, multiple sclerosis, and even COVID-19-related brain fog.
This paradigm shift opens up exciting new possibilities for treatment. Instead of targeting symptoms or secondary effects, future therapies could aim directly at restoring myelin. Early interventions to support myelin health might delay or even prevent the onset of neurodegenerative diseases. Furthermore, the ability of drugs like clemastine fumarate to restore cognitive abilities in aged or diseased brains gives hope that it’s never too late to make a difference. However, much remains to be studied. Clinical trials are needed to confirm whether these promising laboratory results can be replicated in patients. If successful, remyelination therapies could revolutionize how we treat brain disorders in the elderly and beyond.
The study findings were published in the peer reviewed journal: Molecular Neurodegeneration
https://link.springer.com/article/10.1186/s13024-025-00861-w
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https://www.thailandmedical.news/news/breaking-covid-19-news-study-finds-that-brain-demyelination-is-common-in-many-post-covid-individuals,-especially-in-those-with-symptoms-of-depression
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