Scientists Claim They May Have Discovered the Cause of Alzheimer’s

( Researchers believe they may have discovered what causes Alzheimer’s disease.

In recent findings, scientists from the University of California at Riverside said the cause of Alzheimer’s is most likely found on the molecular level. The key to understanding the disease that ravages millions of Americans may have something to do with “tau” proteins that cause the neurofibrillary tangles found in the brains of Alzheimer’s patients.

Researchers previously suggested that amyloid plaques may be the cause. Both amyloid plaques, which are a buildup of amyloid peptides, and neurofibrillary tangles are what doctors look for when diagnosing Alzheimer’s.

According to UCR chemistry professor Ryan Julian, about 20 percent of people have amyloid plaques but show no signs of dementia, leading researchers to conclude that the plaques alone are not the cause of Alzheimer’s. So researchers began to focus on isomers — the different structures a single molecule manufactures.

Julian described an isomer as “the same molecule with a different three-dimensional orientation than the original.” For example, he explained, hands are isomers of each other. They are mirror images, but not exact copies. Julian describes these isomers as “handedness.”

The team scanned proteins in brain samples donated to their lab, and in brains where an accumulation of the tau protein was present but no Alzheimer’s diagnoses were made. They found that the “normal” tau was different-handed than those in individuals who had plaques or tangles and were diagnosed with Alzheimer’s.

Proteins in those with plaques or tangles also survived longer than normal. If a protein survives more than 48 hours, some amino acids in the proteins convert to the “other-handed” isomer. Julian explained just as putting a right-hand glove on your left hand doesn’t work well, so too molecules don’t work the way they’re supposed to if the isomer converts.

The body’s natural process to clear used or defective proteins from cells is called “autophagy.” As people get older, autophagy can slow down. However, it is not clear why. Julian’s team is trying to determine what causes this slowdown.

According to professor Julian, if the slowdown in autophagy is the underlying cause of Alzheimer’s, then it stands to reason increasing autophagy “should have the beneficial opposite effect.”