Study: Isomers May Hold New Clue to Alzheimer's Disease

Scientists may have discovered the cause of Alzheimer's Disease and offered hope from the slate of existing medications to provide a solution. 

Researchers from the University of California, Riverside (UCR) studied the behavior of protein cells in the brain and found a significant difference in those who have had dementia and those who have not, particularly in their ability to clean themselves. 

Neurofibrillary tangles, a buildup of tau protein, and amyloid plaques made up of amyloid peptides are two factors that physicians use to definitively diagnose Alzheimer's. With around 20% of people having plaques but with no signs of dementia, the scientists wondered whether plaques at all are the cause of the disease.

While scanning donated brain samples, they found that the brains of dementia patients and those who developed tangles and plaques had an unusual formation of isomers, which are made of amino acids and can be either left- or right-handed. Living things are made from left-handed amino acids. Typically, proteins have a half-life of less than 48 hours, but if these stay on for far longer, some amino acids eventually become a different-handed form of isomers. 

"If you try to put a right-handed glove on your left hand, it doesn't work too well. It's a similar problem in biology; molecules don't work the way they're supposed to after a while because a left-handed glove can actually convert into a right-handed glove that doesn't fit," said UCR chemistry professor Ryan Julian in a statement.  

Prof. Julian likened handedness to a pair of hands that mirror each other but aren't the same. With these new findings, it appears that the reduced inability to perform self-cleanup, or autophagy, contributes significantly to the progression of Alzheimer's. Not much is known on the reason why but Prof. Julian said his team is planning to explore this further. 

The good news, somehow, is that there are current, commercially-available medications that may be used to improve autophagy, most of which are being utilized for cardiovascular diseases and other illnesses. Autophagy may also be induced through exercise and fasting. Scientists are currently looking into their potential, but the fact that they are already circulating, albeit for other indications, could help hasten the approval process when the time comes. 

"If a slowdown in autophagy is the underlying cause, things that increase it should have the beneficial, opposite effect," noted Prof. Julian. 

Results of the study are published in the Journal of Proteome Research. The study is titled "Does Data-Independent Acquisition Data Contain Hidden Gems? A Case Study Related to Alzheimer's Disease."