Myelin to Blame for Many Neuropsychiatric DisordersNovember 22, 2006What makes the human brain unique? Of the many explanations that can be offered, one that doesn't come readily to mind is - myelin. Conventional wisdom holds that myelin, the sheet of fat that coats a neuron's axon - a long fiber that conducts the neuron's electrical impulses - is akin to the wrapping around an electrical wire, protecting and fostering efficient signaling. But the research of UCLA neurology professor George Bartzokis, M.D., has already shown that myelin problems are implicated in diseases that afflict both young and old - from schizophrenia to Alzheimer's. Now, in a report published in the journal Biological Psychiatry and available online, Bartzokis argues that the miles of myelin coating in our brain are the key "evolutionary change that defines our uniqueness as a species" and, further, may also be the cause of "our unique vulnerability to highly prevalent neuropsychiatric disorders." The paper argues that viewing the brain as a myelin-dependent "Internet" may be key to developing new and novel treatments against disease and aid in assessing the efficacy of currently available treatments, including the use of nicotine (delivered by a patch, not smoking), which may enhance the growth and maintenance of myelin. Myelin, argues Bartzokis, who directs the UCLA Memory Disorders and Alzheimer's Disease Clinic, is "a recent invention of evolution. Vertebrates have it; invertebrates don't. And humans have more than any other species." Bartzokis studied the reported effects of cholinergic treatments, using drugs that are known to improve a neuron's synaptic signaling in people who suffer diseases like Alzheimer's. Furthermore, he notes, some clinical and epidemiological data suggest that such treatments may modify or even delay these diseases. Looking at such effects from a myelin-centric point of view, Bartzokis argues that cholinergic treatments may have nonsynaptic effects as well, perhaps by enhancing myelination and myelin repair - and the better the myelin, the more efficient the neuron signaling and our "Internet's" function. Specifically, such cholinergic treatments may enhance oligodendrocytes, a type of glia cell in the brain that produces myelin during the brain 's development and constantly maintains and repairs it as we age. While more work needs to be done to fully understand the role of nonsynaptic cholinergic effects on brain development, said Bartzokis, his hypotheses can easily be tested through in vivo imaging of the brain to study the breakdown and growth of myelin. That will make it possible to directly test in humans the practical utility of the myelin-centered model of the human brain. Ultimately, it could foster the development of novel treatments, as well as aid in assessing the efficacy of currently available treatments. These include the use of cholinergic treatments that include acetylcholinesterase inhibitors (used to treat Alzheimer's) and nicotine patches. "Through these rather benign interventions," Bartzokis said, "such effects on the brain's vulnerable oligodendrocyte populations may offer exciting opportunities for the prevention of both developmental and degenerative brain disorders. They deserve much closer scrutiny." Bartzokis work was supported in part by a National Institute of Mental Health grant, a National Institute on Aging Alzheimer's Disease Center Grant, Research and Psychiatry Services of the Department of Veterans Affairs and the Sidell-Kagan Foundation. The UCLA Department of Neurology encompasses more than a dozen research, clinical and teaching programs. These programs cover brain mapping and neuroimaging, movement disorders, Alzheimer disease, multiple sclerosis, neurogenetics, nerve and muscle disorders, epilepsy, neuro-oncology, neurotology, neuropsychology, headaches and migraines, neurorehabilitation, and neurovascular disorders. The department ranked No. 1 in 2005 among its peers nationwide in National Institutes of Health funding. For more information, see http://neurology.medsch.ucla.edu/. University of California - Los Angeles |
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| Related Myelin Current Events and Myelin News Articles Drug studied as possible treatment for spinal injuries Researchers have shown how an experimental drug might restore the function of nerves damaged in spinal cord injuries by preventing short circuits caused when tiny "potassium channels" in the fibers are exposed. UCLA study shows brain's ability to reorganize Visually impaired people appear to be fearless, navigating busy sidewalks and crosswalks, safely finding their way using nothing more than a cane as a guide. UCI embryonic stem cell therapy restores walking ability in rats with neck injuries The first human embryonic stem cell treatment approved by the FDA for human testing has been shown to restore limb function in rats with neck spinal cord injuries - a finding that could expand the clinical trial to include people with cervical damage. Rethinking Alzheimer's disease and its treatment targets The standard explanation for what causes Alzheimer's is known as the amyloid hypothesis, which posits that the disease results from of an accumulation of the peptide amyloid beta, the toxic protein fragments that deposit in the brain and become the sticky plaques that have defined Alzheimer's for more than 100 years. Mayo Clinic identifies 2 genes as potential therapeutic targets for multiple sclerosis A Mayo Clinic study has found that two genes in mice were associated with good central nervous system repair in multiple sclerosis (MS). Finding the right connection after spinal cord injury In a major step in spinal cord injury research, scientists at the University of California, San Diego School of Medicine have demonstrated that regenerating axons can be guided to their correct targets and re-form connections after spinal cord injury. Researchers design first model motor nerve system that's insulated and organized like the human body In the July issue of Biomaterials, published by Elsevier, researchers from the University of Central Florida (UCF) report on the first lab-grown motor nerves that are insulated and organized just like they are in the human body. New clue into how brain stem cells develop into cells which repair damaged tissue The joint research, funded by the National Multiple Sclerosis Society and the UK MS Society as well as the National Institutes of Health and Howard Hughes Medical Institute, was conducted by scientists at the University of California San Francisco (UCSF) and University of Cambridge and was published today (01 July) in the journal Genes and Development. MS study offers theory for why repair of brain's wiring fails Scientists have uncovered new evidence suggesting that damage to nerve cells in people with multiple sclerosis accumulates because the body's natural mechanism for repair of the nerve coating called "myelin" stalls out. Neural stem cell differentiation factor discovered Neural stem cells represent the cellular backup of our brain. These cells are capable of self-renewal to form new stem cells or differentiate into neurons, astrocytes or oligodendrocytes. More Myelin Current Events and Myelin News Articles |
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