Stress can cause Alzheimer's

Stress can cause Alzheimer's

by Andrew Smythe

As most people know, Alzheimer's is a form of dementia that results in memory, thinking, and behavioral problems. Specific symptoms include loss of language, behavioral/mood changes, and a difficulty involved with performing daily tasks. The longer a person would have Alzheimer's, the more drastic the symptoms become. The cause of this disease is the build of a protein called amyloid-beta in the brain. Recent studies show that the protein is supported by a hormone called corticotropin, which is released when the body is under stress. 

Corticopin

The blood vessels in the brain have a protective tissue called the Brain-Blood Barrier (BBB) to regulate the energy and metabolism in the brain and the blood stream. When a person is stressed, corticotropin restricts the blood vessels in the brain in order to create an easier passage for glucose and nutrients to other parts of the body; this would allow the person to become more attentive and active during a flight or fight response. The restriction in blood vessels creates an easy passage way for the amyloid-beta proteins to travel across the brain, and cause Alzheimer's.

Dr. Matthew Campbell, Associate Professor of Genetics at Trinity College and one of the researchers involved with studying Alzheimer's, says that this study provides promise for treating Alzheimer's patients in the future. When the bloodstream is opened, it provides a clear passage way to encountering the amyloid-beta proteins. The exact means of doing this is unknown, but the hope is that if the proteins could be removed, then the effects of Alzheimer's would be hindered possibly to the point of non-existence.

First Article

Second Article

Mechanism Sheds Light on How the Brain Adapts to Stress

According to an article from ScienceDaily, Dr. Gil Levkowitz and his colleagues from the Weizmann Institute of Science in Israel have recently published findings exploring the mechanism of corticotropin-releasing-hormone gene (CRH).  CRH is a hormone which is released in response to stressful stimuli that provoke a 'fight-or-flight' mechanism in biological animals.  Inappropriate metabolic regulation of CRH has been shown to be correlated with multiple human psychiatric disorders.

What I found very interesting about this article is the scientists' methodology in investigating general as well as specific gene regulation.  The molecular mechanisms that regulate gene expression, especially when focusing on one specific gene such as CRH, has largely remained not fully understood.  Dr. Lekowitz and his colleagues discovered that 'the protein Orthopedia (Otp), which is expressed in the parts of the brain known to be responsible for the stress response, modulated CRH gene expression.'   Here is the part I found interesting part:  Otp regulates CRH gene expression not by well-documented methods such acting as a protein transcription factor or regulating acetylation of the chromosome, but by regulating the production of two different receptors on the neuron's surface which are responsible for the intracellular signaling that controls CRH production.  This discovery that a protein which functions in gene regulation can have such a commanding effect on the phenotype of an individual who might otherwise be normal wild type for the gene in question (CRH) is almost analogous to epistatic effect, and truly something to think about when considering genetics, gene regulation, and Mendellian hereditary patterns.