Posted by Brigham and Women's Hospital May 13, 2014
It is estimated that some 30 million people suffer from Alzheimer’s disease worldwide. In the United States, over five million Americans, or one in nine, suffer from dementia in the advanced stages of Alzheimer’s disease. Estimates say that the number of Alzheimer’s patients is likely to triple in the next 20-30 years, as people are living longer lives.
Alzheimer’s disease is a progressive, neurodegenerative disease that occurs when nerve cells in the brain die. The disease can cause impaired memory, confusion, personality and behavior changes, impaired judgment, and impaired communication. Dr. Reisa Sperling, Director of the Center for Alzheimer Research and Treatment at Brigham and Women’s Hospital (BWH) calls it the “epidemic of Alzheimer’s.”
Understanding the physiology of Alzheimer’s disease is a work in progress for medical researchers. Research conducted over the past two decades by Dr. Dennis Selkoe at BWH has shown that buildup in the brain of a protein called amyloid-beta is largely responsible for the degenerative effects of the disease, but there is still much to be learned. What is known is that amyloid-beta forms plaques and clumps, inhibiting the brain’s neurons and damaging their connections to one another. Other researchers are investigating the role of a protein called tau which causes “tangles” inside nerve cells, leading to the cells’ death. Though less is known about tau’s significance and its interaction with amyloid-beta, researchers are confident that the cognitive decline associated with Alzheimer’s disease is related to the processes of these two proteins.
Existing therapies for Alzheimer’s disease often provide patients with some symptomatic relief for a short period of time; however, currently there are no treatments that change the underlying process of the disease and slow its progression. The preclinical or asymptomatic stage of Alzheimer’s disease can begin more than 10-15 years before patients experience dementia, and clinical research has identified the need to distinguish between normal aging of the brain and early stages of Alzheimer’s disease in order to develop an effective disease-modifying intervention.
Scientists have now developed a procedure using positron emission tomography (PET) scans that can identify plaque buildup earlier in patients’ lives than ever before. This has opened doors for research and treatment before the onset of dementia.
Earlier this month, a groundbreaking study was launched to test a drug aimed at preventing memory loss due to Alzheimer’s disease. The Anti-Amyloid Treatment in Asymptomatic Alzheimer’s Disease (A4) Study, led by Dr. Sperling, is being conducted at BWH and 60 other sites across the United States, Canada, and Australia. The study will enroll 1,000 asymptomatic participants between the ages of 65 and 85 who are at risk of progressing to the dementia stage of Alzheimer’s disease.
Dr. Sperling says a goal of the study is to learn more about how to treat Alzheimer’s disease in a way that is similar to how heart disease and cancer are treated.
“We’ve made such strides in these diseases by identifying people who have evidence that the disease process has begun in their bodies and starting treatment before they show any symptoms of the disease. This will be the first time we try this type of secondary prevention in Alzheimer’s disease,” she says. “We hope to change the course of Alzheimer’s disease before symptoms such as memory loss begin.”
Learn more: Center for Alzheimer Research and Treatment