From: Andy Soos, ENN
Published September 29, 2010 11:34 AM

High Blood Pressure and Dementia

Blood is obviously important for the body well being. Blood flow through the brain is essential for the delivery of nutrients such as glucose and oxygen that are needed for nerve cells to function. During the early stages of Alzheimer's disease patients can suffer from high blood pressure and blood flow through the brain is reduced: the greater the reduction, the worse patients' dementia may become.

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Dementia is a non-specific illness in which affected areas of cognition may be memory, attention, language, and problem solving. It is normally required to be present for at least 6 months to be diagnosed. In all types of general cognitive dysfunction, higher mental functions are affected first in the process.

A new study will look at the relationship between dementia and high blood pressure, and how blood flow is regulated in the brain. The findings may help researchers identify if some drugs already used for other human conditions may be useful for the treatment of diseases such as stroke and Alzheimer's disease.

Academics at Bristol University's Dementia Research Group, based at Frenchay Hospital, have been awarded a grant from the British Heart Foundation  to assess whether drugs that block a small naturally produced molecule called endothelin-1 can improve blood flow through the brain.

Back in 2007 having hypertension, or high blood pressure, was proposed as reducing blood flow in the brains of adults with Alzheimer's disease. this was presented in a study presented the annual meeting of the Radiological Society of North America.

Again in 2007 other doctors spent 2 years examining over one thousand drugs to see whether they might have any benefits for the treatment of Alzheimer's disease and dementia. Out of 55 candidate drugs which are prescribed for hypertension, the team detected 7 promising ones. They found that these drugs are able to prevent the production of beta-amyloid, which is a potential cause of Alzheimer's disease.

In animal models of dementia a reduction in blood flow occurs well before the onset of Alzheimer-like damaging changes to brain tissue. The most potent cause of the narrowing of blood vessels seems to be a small molecule called endothelin-1 (ET-1). This molecule is produced by the action of endothelin-converting enzymes (ECEs).

The Bristol-based academics recently found that ECE in the brain of Alzheimer patients was abnormally high. One of the hallmarks of Alzheimer disease is the large amount of amyloid β, a toxic molecule which accumulates in the brain of patients. The Bristol-based researchers have shown that ECE production increased when nerve cells were exposed to amyloid β, long before people start to display the Alzheimer memory problems.

The further results of the new study will be useful in helping to treat Alzheimer patients in early stages of the disease.


For further information: http://www.bristol.ac.uk/news/2010/7234.html

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