New research suggests that some cases of Alzheimer’s disease may be caused by the breakdown of the myelin sheath that coats and protects nerve cells. Myelin is a fat that contains very high levels of cholesterol. It acts as an insulator, and speeds up connections between neighboring nerve cells. As the brain continues to develop well into adulthood, myelin is produced in greater and greater quantities. Eventually the increased production of myelin increases cholesterol levels in the brain by such an extent that they trigger the production of a toxic protein that attacks myelin. Professor George Bartzokis from the University of California Los Angeles believes that the resulting loss of myelin disrupts the transmission of nerve signals and ultimately leads the development of the amyloid plaques that are characteristic of Alzheimer’s. Bartzokis says that the body was designed to myelinate through the natural lifespan, but that advances in medical science mean that our lifespan has extended far beyond that for which the brain was designed. He adds that because of the lengthening of the human lifespan, the myelin loss that occurs in middle age is a normal part of growing old. Although, Bartzokis suggests that it might be possible to limit myelin breakdown during middle age by taking cholesterol-lowering drugs, anti-inflammatory medications, or by improving diet and exercise.
SOURCE/REFERENCE: Reported by www.bbc.co.uk on the 30th December 2003.
