July 28, 2008

Blood-Pressure Drugs Could Help Fight Alzheimer’s

By John von Radowitz

Commonly used blood pressure drugs could prove to be powerful new weapons against Alzheimer's, new research has suggested.

Scientists found that the drugs, known as angiotensin receptor blockers (ARBs), both prevented the disease occurring and slowed its progression.

The effect was "striking", according to the US researchers who reported their findings at an Alzheimer's conference in Chicago.

A database at the US Department of Health Systems Veterans Affairs was used to examine the records of about six million patients treated for high blood pressure between 2001 and 2006. Those taking ARBs were 35 per cent to 40 per cent less likely to develop Alzheimer's disease or other forms of dementia than patients on different medications.

Patients already suffering from Alzheimer's when they started taking ARBs had a 45 per cent reduced chance of developing delirium, being admitted to a nursing home, or dying prematurely. Those who had experienced strokes before or during the course of their illness appeared to benefit most from the drugs.

Study leader Professor Benjamin Wolozin, from Boston University School of Medicine, said: "For those who already have dementia, use of ARBs might delay deterioration of brain function and help keep patients out of nursing homes. The study is particularly interesting because we compared the effects of ARBs to other medications used for treating blood pressure or cardiovascular disease."

The findings were presented today at the 2008 International Conference on Alzheimer's Disease in Chicago.

Previous animal studies have suggested that ARBs might help prevent nerve cell injury from blood vessel damage, or promote the recovery of damaged nerve cells.

About 700,000 people in the UK suffer from some form of dementia, and more than half have Alzheimer's disease.

In less than 20 years it is expected that nearly a million Britons will be afflicted by dementia. This could soar to 1.7 million people by 2051.

ARBs are normally prescribed as a second-choice treatment to patients unable to tolerate ACE inhibitors, another class of blood pressure drug. Both drugs interfere with a biochemical pathway involving angiotensin, an organic chemical that constricts blood vessels. They allow the vessels to relax and widen so that more blood can flow through them.

High blood pressure in mid-life is known to be associated with an increased risk of Alzheimer's. The disease is closely linked to the appearance of beta-amyloid protein deposits in the brain, and damaged arteries.

Cardiovascular factors also play an important role in other forms of dementia.

Professor Clive Ballard, head of research at the Alzheimer's Society, said: "High blood pressure doubles risk of Alzheimer's disease and increases risk of stroke.

This study highlights that it is becoming increasingly important to investigate anti-hypertension (anti-high blood pressure) drugs as a potential treatment for dementia, not just a risk factor.

"These findings will be important in stimulating further research into the relationship between anti-hypertension drugs and the development of dementia.

A proper clinical trial is now needed to investigate if this particular class of drug can benefit thousands of people living with this devastating condition."

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