Could Alzheimer disease, a form of dementia that accounts for almost 70% of all the cases of dementia arise from the contaminated remains of infections?
The research of a team of Harvard investigators led to the hypothesis that even mild infections could leave debris in the brain and cause people to develop Alzheimer. This would explain the mysterious plaques that form in the sufferers’ brains.
Although it is not yet confirmed, the idea makes sense to many Alzheimer experts. The study was published Wednesday, May 25th in the journal Science Translational Medicine and if the research holds up, it will have incredible implications for treating and preventing the degenerating disease.
The scenario seems ripped from the sci-fi books: a pathogen, be it a virus or bacteria, enters the brain, passes through the blood-brain membrane and starts attacking. But the brain’s immune system instantly creates a beta amyloid protein cage to trap the invader.
The bug caught in the beta-amyloid web then slowly dies off. The problem seems to be that these minuscule protein traps are not discarded. They’re probably Alzheimer’s hallmark plaques.
The bug trap hypothesis has been confirmed in lab work on neurons engineered in Petri dishes with fruit flies, mice, roundworms, and yeast. Finding similar sequence in humans is the next step. Funding and plans are set for a multicenter program where human brains will be examined.
Doctor Michael Weiner, a radiology professor and principal investigator at the Alzheimer’s Disease Neuroimaging Initiative said these results are “interesting and provocative.” The California center where the doctor works represents a national effort to track biomarkers of dementia (like blood proteins) and brain signals that warn about the presence of the Alzheimer disease.
This particular study began when doctor Robert Moir of the Harvard Medical School and Massachusetts General Hospital had the idea to study amyloid, a normal brain protein who’s role was not clear until recently.
Scientists considered amyloid to be trash accumulating in the aging brain, but Dr. Moir noticed it looked like proteins from the immune system’s first line of defense. Studying how living animals react with and without it, the team discovered mice without it would be ravaged by infection and mice with it, would have the infectious microbe confined.
There’s now new hope for Alzheimer disease to be cured, but “big, big” steps are still to be made.
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