There could be a link between particulates and Alzheimer’s disease. This is according to a study just released which has found particulates in the brains of people who have died from this disease. This adds to the list of problems that particulates cause such as lung disease and strokes. Alzheimer’s disease is of course complex and a number of agents have been implicated as its cause. Also just just because there is correlation does not mean there is causation. These particles contain small amounts of metals (magnetite).
There is some logic to this scientifically. In Alzheimer’s disease a protein amyloid-β forms abnormal filaments in the brain. These aggregate and damage the brain’s neural pathways. The expression of the amyloid-β is partially controlled by metals such as iron, zinc and copper. In addition iron and copper can undergo a series of oxidation and reduction reactions with hydrogen peroxide. Hydrogen peroxide is produced by the body as a natural product of metabolism. When it reacts with these metals it forms free radicals which are molecules with a single unpaired electron. Chemically this is highly unstable and such groups can react very rapidly with almost any molecules in the body causing great damage. Living organisms that are aerobic have evolved a series of enzymes that break the peroxide down very rapidly. The problem is if large amounts of metals become embedded then this system is likely to be overwhelmed.
A large number of other factors have been implicated in this terrible disease such as genetic factors and processes related to ageing. Nevertheless there is a a lesson here that we should cut the causes of particulates which includes all combustion processes down for our own good, the worst offenders being cars and coal fired power stations.
Link to the paper here.