Brain uses marine omega-3 to protect cells against toxic protein plaque
by Craig Weatherby and Randy Hartnell
Scientists at Louisiana State University have long been in the forefront of brain research. Thanks to studies led by LSU researchers—which were completed before hurricane Katrina arrived and published just last week on the web—we now know how one of the two omega-3 fatty acids in fish oil exert the protective effects against Alzheimer’s Disease (AD) seen in the many studies that have examined various population’s incidence of AD, relative to their characteristic omega-3 intake levels.
The results of many previous studies indicate that low dietary intake of DHA correlates with poor cognitive health, especially with regard to mood, attention, and memory. As the authors of a recent review article put it, “decreased blood levels of omega-3 fatty acids have been associated with several neuropsychiatric conditions, including Attention Deficit (Hyperactivity) Disorder, Alzheimer's Disease, Schizophrenia, and Depression.”
DHA is a physiologically essential omega-3 found only in fish oil (fat), and concentrated in the fat of coldwater species such as sardines, tuna, sablefish, and salmon. Researchers report that DHA constitutes a large and physiologically essential portion of the cell membranes in key parts of our brains and eyes.
Dr. Nicolas G. Bazan, leader of the recent DHA-Alzheimer’s studies, described the role of DHA in a related scientific article published in April of 2005 (we've added term definitions in brackets ):
“Synaptic membranes [envelopes covering the communication junctions between brain cells] and photoreceptors [light sensors in the eye] share the highest content of DHA of all cell membranes. DHA is involved in memory formation, excitable membrane function, photoreceptor cell biogenesis and function, and neuronal signaling, and has been implicated in neuroprotection [protecting threatened brain cells].”
In other words, DHA is critical to both visual and brain function, and the NPD1 the body makes from this marine omega-3 promotes survival of brain cells
Study illuminates how DHA protects against AD
The new results reported by LSU scientists show that DHA lowers levels of beta-amyloid: a protein that produces the damaging “plaque characteristic of Alzheimer's patients brains.
In a breakthrough for the understanding of how DHA protects against Alzheimer’s, the researchers discovered neuroprotectin D1 (NPD1): a previously unknown anti-inflammatory compound that the body makes from DHA. The new results show that NPD1 plays a key role in protecting the brain from the relentless brain-cell die-off caused by accumulation of the inflammatory beta amyloid protein plaques that characterize Alzheimer's disease.
Dr. Bazan, the director of LSU’s Neuroscience Center of Excellence, led the team that conducted studies there and at Brigham & Women's Hospital in Boston. They examined human brain samples from six patients who had died with Alzheimer's disease, and six age-matched control samples from people free of AD at the time of their deaths.
The researchers also looked for any changes within the brain cells of AD sufferers, and examined the area of their brains key to memory and thought function (hippocampal cornu ammonis region 1). Dr. Bazan reported that the area showed 20- to 25-fold decreases in NPD1, compared with other areas in the same brain.
And, when the team conducted cell studies designed to mimic the effects of aging, they found that adding DHA to cell cultures cut production of toxic beta amyloid proteins and raised production of NPD1. In turn, NPD1 was seen to suppress the damaging inflammation caused by Abeta42 while switching on the “anti-apoptotic” genes that help keep AD-afflicted brain cells alive.
Feeding the brain’s own self-protective power
The New York Times Syndicate interviewed Greg M. Cole, M.D., associate director of the Alzheimer's Disease Research Center at the University of California, Los Angeles, concerning the meaning of the joint LSU-B&WH studies. Dr. Cole was quoted as saying the studies show that NPD1 offers “… several important protective contributions. This study also shows that both DHA and its NPD1 product are effective in treating human brain cells and reducing the inflammation and toxicity from a toxin called beta amyloid that is widely believed to cause Alzheimer's.”
In other words, if you want to reduce the risk and severity of Alzheimer's and more common forms of senile dementia, it makes good sense to eat plenty of fatty fish, or take a quality fish oil.
- Lukiw WJ, Cui JG, Marcheselli VL, Bodker M, Botkjaer A, Gotlinger K, Serhan CN, Bazan NG. A role for docosahexaenoic acid- derived neuroprotectin D1 in neural cell survival and Alzheimer disease. J Clin Invest. 2005 Sep 8; [Epub ahead of print]
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- Bazan NG. Lipid signaling in neural plasticity, brain repair, and neuroprotection. Mol Neurobiol. 2005 Aug;32(1):89-104.
- Bazan NG. Neuroprotectin D1 (NPD1): a DHA-derived mediator that protects brain and retina against cell injury-induced oxidative stress. Brain Pathol. 2005 Apr;15(2):159-66. Review.
- Mukherjee PK, Marcheselli VL, Serhan CN, Bazan NG. Neuroprotectin D1: a docosahexaenoic acid-derived docosatriene protects human retinal pigment epithelial cells from oxidative stress. Proc Natl Acad Sci U S A. 2004 Jun 1;101(22):8491-6. Epub 2004 May 19.
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