Alzheimer Disease

Research into the cause of Alzheimer disease focuses on the nature of the basic biology of the disease and the development of drugs that will counteract or prevent the deterioration associated with the disease. These quests are difficult, as the cause of Alzheimer disease at the molecular level is still unknown. Similarly, the formation of amyloid plaques and why the connections between brain cells are destroyed are unclear. Until the exact biological causes of Alzheimer disease are identified, drug trials may be used more for research than therapy.

A key to understanding the disease and the best hope for an effective treatment may lie in a better understanding of the beta-amyloid protein that forms the plaques in the brain. The formation and biological function of beta amyloid protein is still unclear, even though its existence has been known since 1906, when Alois Alzheimer saw the protein in plaques in the brain of a patient with dementia.

Researchers are striving to decrease the production of beta-amyloid protein or of the larger amyloid precursor protein, from which it is derived, in hopes of decreasing the formation of the damaging plaques.

Other researchers have developed animal models of Alzheimer disease. By introducing into mice genes that code for a changed form of human beta-amyloid protein, scientists have created animals that experience brain degeneration and plaques. Tests with these animals may one day help determine the role of beta-amyloid protein in Alzheimer disease and could help researchers find drugs for treatment.

Not all researchers agree on the significance of beta-amyloid protein in the progression of Alzheimer disease. Colored positron emission tomography (PET) brain scans comparing a normal brain (left) with the brain with Alzheimer disease. © Photo Reasearchers. Reproduced by permission. Indeed, some scientists doubt that the beta-amyloid protein is the key to understanding and treating the disease. Rather, they suppose that the accumulation of large amounts of beta-amyloid protein is a response to an asyet undiscovered cause.