Sunday, November 13, 2005

Facets of Alzheimer Disease

As pointed out by Dr. Serani, this (November) is National Alzheimer Disease Month.  She has a number of useful links for those interested in finding more information.  If you are wondering how various causes get to be associated with various months, or weeks, or days, or years, or decades, it is done by decree.  In this case, President Reagan declared November as National Alzheimer Disease Month, back in 1983.  
Acetylcholine chemical structure
Another historical note: one of the earliest findings in the neurobiology of Disease was the discovery that brain cells that release acetylcholine die prematurely.  This is what led to the idea of using acetylcholinesterase inhibitors to treat the disease.  The idea here is fairly simple: if those cells die, there won't be enough acetylcholine in the brain; if you inhibit the enzyme that breaks down acetylcholine, then the amount of acetylcholine will be increased.  

The thing is, nothing in the brain is that simple.  Acetylcholinesterase inhibitors do help, but the improvements are modest at best.  Obviously, it would be far better to keep the neurons from dying in the first place.  There is some evidence (1 2) that fish oil can help, at least in mice; it is not yet clear how much clinical benefit, if any, can be expected from fish oil supplements for humans.  

Another line of attack was suggested by the finding that acetylcholinesterase inhibitors have an additional, unexpected effect.  In addition to increasing the amount of acetylcholine available in the synapses in the brain, the drugs also cause a reduction in the production of the inflammatory mediator, interleukin-1.  Researchers at the Hebrew university of Jerusalem have discovered a drug, EN101, that destroys the messenger RNA that cells use to produce interleukin-1.  Although it is way too early to know in EN101 will have any clinical utility for humans, it certainly is encouraging to see new developments that present promising new avenues of attack.