brain at risk? Researchers wonder whether high homocysteine could help turn a normal brain (bottom) into one with Alzheimer's disease (above).
In the struggle to identify people who may be at risk for Alzheimer's disease, the researchers looked at this link: risk factors of Alzheimer's disease share of heart disease, such as high cholesterol. Now, researchers report that the two diseases share another common sign. High levels of a molecule called homocysteine, already involved in diseased hearts, also appears to significantly increase the risk of Alzheimer's disease.
In well-nourished people, homocysteine amino acid is decomposed by B vitamins and folic acid. But people who lack these key nutrients can have high levels of homocysteine, and high levels have been linked to heart disease. Because high cholesterol has been in some studies related to Alzheimer's disease, some scientists have questioned whether high homocysteine levels may also help trigger the brain disorder.
To find out, University neurologist Sudha Seshadri of Boston and his colleagues turned to the Framingham Heart Study, which began following the 5209 health volunteers in 1948 and was widely used in medical studies. In the mid 1970s, volunteers have joined an effort to examine dementia (none had at the time) and have since undergone the regular cognitive function tests. The researchers also collected and stored periodic blood samples of the participants.
group collected blood samples of Seshadri as far back as 1979 1092 Member of the study of dementia. Scientists have measured the levels of homocysteine and levels of vitamins B6 and B12; they also looked for variants of a gene called APOE that help predict the risk of someone with Alzheimer's disease. The results were surprising: High levels of homocysteine, the more a person was likely to develop Alzheimer's disease later. When plasma homocysteine has reached a high level - above 14 micromoles per liter of blood - the risk of disease has doubled. An increase of 5 micromoles was linked to an increased risk of disease of 40%. The researchers were surprised, they report in February 14 issue of The New England Journal of Medicine , to find that the risk factor found is not dependent on levels of vitamin someone or APOE profile.
the strength of the association is powerful, said Joseph Loscalzo, chairman of the department of medicine at the Medical Center of Boston University, who was not involved in the study. But he and others wonder why homocysteine has such an effect. And we do not know, he adds, if a person can protect against Alzheimer's disease by taking vitamins that homocysteine levels.
Links
Framingham Heart Study
The Alzheimer's research at Boston University
the Alzheimer Research Forum
More about homocysteine
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