Scientific American Tries to Catch Up

The October 2018 issue of Scientific American includes an article, "How Exercise Might 'Clean' the Alzheimer's Brain."  It begins by acknowledging how the major pharmaceutical companies have thrown their hands up over the search for a drug to cure AD.  The most recent trials have failed to improve cognition in people with AD, and the drug companies are, at least temporarily, at a dead end.  The recent drugs have sought to remove amyloid plaques from the brain, but that hasn't led to improved cognition.  According to the article (and according to Beating the Dementia Monster) this is challenging the amyloid hypothesis.  The amyloid hypothesis has been pretty close to the center of the search for a cure for AD.  (I'm not sure where the study I cited in my July 13 post fits into this narrative.)

Recall that the amyloid hypothesis notes the accumulation of amyloid plaques on neurons, and is assumed to impede neural activity between the cells.  The plaques also appear to play a role in the deaths of neurons.  Therefore, removing the amyloids from the brain should stop the progress of AD and lead to improved cognition.  But it doesn't.  

The article cites research with mice that correlates mice getting exercise with encouragement of the generation of new brain cells (neurogenesis) in the hippocampus.  To quote the Scientific American article, "The researchers found that exercised animals from a mouse model of Alzheimer’s had greatly enhanced memory."  As has been noted before, the article cites the role of brain-derived neurotropic factor (BDNF) in this neurogenesis, and I struggled to find anything in the research report that we didn't discuss in Beating the Dementia Monster.  What seemed new in the report was to look at exercise as creating an environment in the brain that encourages neurogenesis, but this just seemed to me to be looking at what we already know using different language.  There was an implication, however, to think in terms of a drug that would create an environment similar to that created by exercise.

The article is relatively short, and interested people should read it.  But there wasn't much new in it, and I was disappointed.