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The exact cause of alzheimer's disease is still uncertain. Genetic mutations, for example, clearly do cause the disease. Some researchers feel that environmental factors may be important causes of alzheimer's disease.
What Causes Alzheimers
Cause of Alzheimers Disease & Risk Factor
The exact cause of alzheimer's disease is still uncertain. Genetic mutations, for example, clearly do cause the disease. For example, mutations in the presenilin 1 gene cause more than half of all cases of early-onset alzheimer's disease.
Most researchers today believe the immediate cause of alzheimer's disease is the abnormal build-up in the brain of a substance called amyloid beta peptide [abbreviated AB]. AB is formed by abnormal cleavage of a parent substance called amyloid precursor protein [abbreviated APP]. APP , which protects brain cells from injury, is a protein made up of up to 771 amino acids. AB, which is only 40 to 43 amino acids long, is formed when two enzymes, beta secretase and gamma secretase , cleave APP abnormally, thus releasing AB. Normal cleavage of APP by alpha secretase enzymes does not form AB.
Genetic mutations that result in early-onset alzheimer's disease increase the amount of AB in the brain. Animals have been created in the lab,and these mice and rats have had alzheimer genes inserted in their DNA. Mice or rats, with human alzheimer genes inserted in their DNA, are known as transgenic animals. Transgenic animals show build up of AB in their brains just like alzheimer patients do. Transgenic animals also show decreased learning and memory, like alzheimer patients.
Elan Pharmaceuticals recently developed a potential vaccine for alzheimer's disease. The company has found that transgenic mice, which normally have high AB levels in their brains as they age, show less build-up of AB when given the new vaccine. In addition, the transgenic mice show better memory and learning capacity than transgenic mice not given the vaccine. Work with such transgenic animals seems to show that AB is the immediate cause of alzheimer's disease. Drug companies are looking for drugs that can reduce levels of AB in the brain, blood, and cerebrospinal fluid.
An exciting new development is a recent study which reports that people who take cholesterol-lowering drugs seem to have a lower incidence of alzheimer's disease. Researchers now know that cholesterol-lowering drugs may actually stop the production of AB. For example, one commonly-used cholesterol-lowering drug, simvastatin, directly reduces the production of AB in cultured brain cells that have been engineered to overproduce AB. This new work suggests that cholesterol may be involved in AB production.
Some researchers feel that envvironmental factors may be important causes of alzheimer's disease. For example, in the early 1980's, alzheimer researchers were excited about the possibility of aluminum as the cause of alzheimer's disease. Aluminum may play an intriguing role in alzheimer's disease, as we shall see in the next section.
Reprinted with permission - Caregiving-solutions.com - Mr. Jim Knittweis, Owner, Alzheimer Solutions | 
