Jun 102011

Blood test for Alzheimer's?Oxidation and free radical damage are natural occurrences as our bodies are subjected to toxins and stressors from everything we encounter throughout our lifespan. When oxidation occurs, our bodies respond in the best way they know how: they reach for protective resources from within our cells to combat the damage and maintain our health. If these resources are unavailable, inflammation will occur. The processes of oxidation, free radical production and cell damage are thought to be involved in cancer, heart disease, Alzheimer’s disease and even aging itself. Inflammation is also known to be part of many disorders as well.

In a recent study* published  in the Journal of Alzheimer’s Disease, researchers induced oxidation in blood samples from Alzheimer’s patients and found that it was lower in a natural steroid called dehydroepiandrosterone (DHEA) as compared to healthy people. DHEA is a hormone produced naturally in the adrenal glands. The body then converts it into the hormones estrogen and testosterone. DHEA helps the brain work and protects it from damage. Interestingly, the level of DHEA in the body peaks between ages 20 and 30 and then decreases progressively with age. This difference in DHEA levels observed in the present study between Alzheimer’s patients and healthy people means that a simple blood test could potentially be used to help diagnose the disease.
In blood taken from healthy people, oxidation led to a 53 percent increase in DHEA. However, when the test was repeated on blood from people with Alzheimer’s, there was a much smaller increase in DHEA — around 14 percent for people with mild Alzheimer’s and just 4 percent for severe Alzheimer’s.

The researchers hypothesize that in people with Alzheimer’s, the brain has used up the chemicals needed to produce DHEA in an effort to protect the brain. So, when treated in a lab, blood from healthy people can produce more DHEA, but not blood from Alzheimer’s patients.

It’s not clear yet exactly how reliable the test would be in practice. The differences in DHEA between healthy people and those with the early stages of Alzheimer’s may not be big enough for the test to accurately identify Alzheimer’s until the more advanced stages, which would limit its usefulness.

There also were signs that the test could give different results for men and women, although it is difficult to say with the relatively small number of people in the study. The study looked at just 86 people.

This study raises the possibility of a new simple blood test for Alzheimer’s that could be used alongside the current methods of diagnosis, which include a medical history, neuroimaging and tests of memory. Certainly, the results of this study will need to be validated on a larger sample of subjects, but the findings are quite encouraging.

* G. Rammouz, L. Lecanu, P. Aisen, V.Papadopoulos, A Lead Study on Oxidative Stress-Mediated Dehydroepiandrosterone Formation in Serum: The Biochemical Basis for a Diagnosis of Alzheimer’s Disease. Journal of Alzheimer’s Disease, May 4th, 2011.

Michael S. Rafii, M.D., Ph.D.

Director, Memory Disorders Clinic
Associate Medical Core Director, Alzheimer’s Disease Cooperative Study
University of California San Diego

This post originally appeared in Alzheimer’s Insights, an ADCS Blog.

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  2 Responses to “A Potential Blood Test for Alzheimer’s Disease”

  1. So, if we give someone DHEA we can reverse the onset?

  2. I hope that they continue to look into this. My mother died a few years ago, but the last several months of her life were horrible….I wish that on no one. I can say tho', I became increasingly dependant on baby food to feed her and I did notice some "improvement" too far long for any real help but the baby food with dhea in it definitely kept us from having a bunch of bad days. These days I take DHEA an it does seem to keep me more alert and on my toes.

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