Biology

Balance May Play Role in Alzheimer’s

Like the Yin and Yang in ancient Chinese philosophy, two peptides — Aß42 and Aß40 — must be in balance for normal brain function, according to researchers at Rensselaer who are challenging current thinking on the causes and prevention of Alzheimer’s disease.

The researchers have found that a specific imbalance between the two peptides may cause the fatal neurological disease.

“When the peptides are produced in the correct proportions, the brain is healthy; but when that delicate balance is changed, pathological changes will occur in the brain and the person’s memories become hazy, leading to eventual dementia,” says Chunyu Wang, lead researcher and assistant professor of biology.

Wang expects this imbalance could be the main factor in the progression of Alzheimer’s disease. If correct, the addition of Aß40 may stop the disease’s development.

Peptides are formed by the linking of different amino acids. Aß40 and Aß42 have been previously found in deposits, called senile plaques or amyloid plaques, in brains afflicted with Alzheimer’s disease.

Prior research has uncovered that increased levels of Aß42 become toxic to brain cells when individual molecules of Aß42 combine to form fibril chains, a process called aggregation. But the role of Aß40, which is also found in senile plaques and generated from the same protein as Aß42, has not been clearly established. Wang set out to determine what role this peptide played in the generation of Aß42 aggregates.

Wang’s experiments show that when there is 15 times more Aß40 than Aß42, the formation of Aß42 fibrils is almost completely stopped. “This means that the introduction of Aß40 to tip the peptide balance toward Aß40 could potentially halt or slow down the progression of the Alzheimer’s in the human brain,” he says.