Alzheimer's Might Not Actually Be a Brain Disease, Expert Says - ScienceAlert

My laboratory at the Krembil Brain Institute, part of the University Health Network in Toronto, is devising a new theory of Alzheimer's disease.

Rather, we believe that Alzheimer's is principally a disorder of the immune system within the brain.

We believe that beta-amyloid is not an abnormally produced protein, but rather is a normally occurring molecule that is part of the brain's immune system.

When brain trauma occurs or when bacteria are present in the brain, beta-amyloid is a key contributor to the brain's comprehensive immune response.

When regarded as a misdirected attack by the brain's immune system on the very organ it is supposed to be defending, Alzheimer's disease emerges as an autoimmune disease.

In our model of Alzheimer's, beta-amyloid helps to protect and bolster our immune system, but unfortunately, it also plays a central role in the autoimmune process that, we believe, may lead to the development of Alzheimer's.

Though drugs conventionally used in the treatment of autoimmune diseases may not work against Alzheimer's, we strongly believe that targeting other immune-regulating pathways in the brain will lead us to new and effective treatment approaches for the disease.

For example, some scientists believe that Alzheimer's is a disease of tiny cellular structures called mitochondria – the energy factories in every brain cell.