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Amyloid is excreted by all neurons, but rates increase with agingand dramatically accelerate in Alzheimer's. Astrocytes, whichdeliver blood, oxygen and nutrients to neurons in addition tohauling off some of their garbage, get activated and inflamed byexcessive amyloid. Now researchers have shown another way astrocytes respond is bypackaging the lipid ceramide with the protein PAR-4, whichindependently can do damage but together are a more "deadlyduo," said Dr. Erhard Bieberich, biochemist at the MedicalCollege of Georgia at Georgia Health Sciences University. "If the neuron makes something toxic and dumps it at yourdoor, what would you do?" said Bieberich, corresponding authorof the study published in the Journal of Biological Chemistry . "You would probably do something to defend yourself." The researchers hypothesize that this lipid-coated packageultimately kills them both, which could help explain the brain-celldeath and shrinkage that occurs in Alzheimer's. "If theastrocytes die, the neurons die," Bieberich said, notingstudies suggest that excess amyloid alone does not kill braincells. "There must be a secondary process toxifying theamyloid; otherwise the neuron would self-intoxicate before it madea big plaque," he said. "The neuron would diefirst." One of many avenues for future pursuit include whether a ceramideantibody could be a viable Alzheimer's treatment. In theresearchers' studies of brain cells of humans with Alzheimer's aswell as an animal model of the disease, antibodies to ceramide andPar-4 prevented astrocytes' amyloid-induced death. Ceramide and Par-4 get packaged in lipid-coated vesicles calledexosomes; all cells secrete thousands of these vesicles butscientists are only beginning to understand their normal function.When exosomes become deadly, they are called apoxosomes. Ceramide and Par-4 are typically not in a vesicle, rather in twodistinct parts of a cell. Ceramide appears to take the lead inbringing the two together when confronted with amyloid. Bieberichand colleagues at the University of Georgia reported in 2003 thatthe deadly duo helps eliminate duplicate brain cells that occurearly in brain development when their survival could result in amalformed brain. They suspected then that the duo might also have arole in Alzheimer's. Risk factors for Alzheimer's include aging, family history andgenetics, according to the Alzheimer's Association. Increasingevidence suggests that Alzheimer's also shares many of the samerisk factors for cardiovascular disease, such as high cholesterol,high blood pressure and inactivity. Drs. Guanghu Wang, research scientist, and Michael Dinkins,postdoctoral fellow, are co-first authors on the study funded bythe National Institutes of Health. We are high quality suppliers, our products such as Super Grip Belt , Polyurethane Tubing Manufacturer for oversee buyer. To know more, please visits Reinforced Cord.
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