Alzheimer’s disease is a progressive condition that affects memory, thinking, language and behavior. It’s characterized by two important changes in the brain: plaques and tangles. Plaques are sticky clumps of beta-amyloid protein fragments. These deposits form outside and around nerve cells. Neurofibrillary tangles are twisted fibers of a protein, called tau, which build up inside the brain’s nerve cells.

In early stages, patients with Alzheimer’s may show mild signs of forgetfulness or confusion (called mild cognitive impairment). As the disease progresses, patients have a hard time remembering recent events, recognizing familiar places, finding the right words when speaking or doing complex tasks (like keeping a checkbook). Eventually, they may wander, make poor decisions, have mood swings and become unable to care for themselves.

According to the Alzheimer’s Association, about 5.2 million Americans have Alzheimer’s disease. It’s most common in people over 65, but can occur at younger ages. Women are affected more often than men. As our population ages, the number of older Americans with Alzheimer’s will approach 7.7 million by 2030 and 11 to 16 million by 2050.

Biomarkers for Alzheimer’s Disease

Researchers at the University of Pennsylvania School of Medicine in Philadelphia are looking at two biomarkers that may indicate risk for development of Alzheimer’s disease. The markers are two proteins - amyloid beta42 peptide and tau. Amyloid beta42 is normally produced and broken down by the body during normal metabolic processes. However, people with Alzheimer’s disease have elevated levels of this protein and it’s believed to contribute to the development of the abnormal plaques in the brain.

The tau protein is also found naturally in the brain cells. But in Alzheimer’s disease, abnormal forms of the protein accumulate. The tau protein is believed to be associated with the development of brain tangles in Alzheimer’s disease.

Investigators have found the amyloid beta42 peptide and tau protein can also be found in the cerebrospinal fluid, the fluid that surrounds the brain and spinal cord. Levels can be measured by inserting a needle into the spinal space and withdrawing a small amount of the fluid (a procedure called a lumbar, or lower spine, puncture). In fact, Biomarker Researcher, Leslie Shaw, Ph.D., recently reported they could use measurements of these two biomarkers to accurately predict if a patient with mild cognitive impairment will go on to develop Alzheimer’s disease.

Shaw says the test is a long way from being used as a screening tool for Alzheimer’s disease. Annually, about 6 to 25 percent of those with mild cognitive impairment progress to Alzheimer’s disease. But not everyone with mild symptoms develops more severe symptoms. With further testing and confirmation of its accuracy, it may one day be used to detect Alzheimer’s disease at its earliest stages, enabling patients to get treatments that may slow or halt progression of symptoms.

For general information on Alzheimer’s disease:

Alzheimer’s Association

Alzheimer’s Foundation of America