Tuesday, June 29, 2010

New Frontiers in the Treatment of Alzheimer’s

Alzheimer’s is a devastating disease of the human brain that ordinarily displays symptoms in old age. It is an ailment that is characterized by progressive dementia that totally incapacitates the patient and ultimately ends in death.

Alzheimer’s is characterized by a gradual build up of protein fragments referred to as amyloid-beta peptides. These fragments accumulate in the intercellular spaces within the brain. The disease process ultimately leads to profound cell death. Anti-amyloid drugs and a vaccine have been developed to combat this disease. These novel therapies have so far been disappointing.
As a result of extensive research into the disease process, there is now a new understanding of disease progression. The buildup of the amyloid-beta peptides begins from 5-20 years before diagnosis. In addition a protein called, TAU that normally functions to maintain the infrastructure within nerve cells (neurons) is modified leading to disruption of normal cell function. This seems to occur 1-5 years prior to the appearance of symptoms, and finally, brain shrinkage becomes noticeable as a result of significant cell death 1-3 years before diagnosis.

On account of these findings, the current understanding is that the failure of new therapies to effect a beneficial change may be due to the fact that when treatments are initiated the brain damage is already too advanced to yield beneficial results.

In the town of Medellin, Columbia there are approximately 5000 members of 25 extended families who develop early-onset Alzheimer’s. This is a result of dominant gene that is found in less than one percent of 27 million Alzheimer’s cases worldwide (2006). Individuals of these families, therefore, allow an ideal setting to test this hypothesis. The planned trial is referred to as the Alzheimer’s Prevention Initiative (API). The overall approach is to have appropriate candidates – apparently healthy with the deleterious gene – who are around the age of forty treated with the anti-myeloid therapies as previously discussed.

If this approach yields promising results, - the treatments delay or stop the inexorable progression of the disease - this would be exciting news, especially since the U.S. population is aging.

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