Alzheimer News:

Study: Certain High Blood Pressure Drugs May Slow Alzheimer's

Certain ACE inhibitor drugs used to control high blood pressure may also slow the deterioration in the brain caused by Alzheimer’s disease, according to a study reported in the October 12 issue of the journal Neurology.

The researchers found that only ACE inhibitors that penetrate the blood-brain barrier were shown to have the effect on Alzheimer’s. The blood-brain barrier is a natural protective mechanism that shields the brain from foreign substances.

The study involved 162 Japanese with mild to moderate Alzheimer’s disease and high blood pressure who were divided into three treatment groups.

For one year, each group received either a brain-penetrating ACE inhibitor, a non-brain-penetrating ACE inhibitor or another type of blood pressure drug, called a calcium channel blocker. Those in the brain-penetrating ACE inhibitor groups received one of two drugs – perindopril or captopril.

The thinking and memory skills of those who took the brain-penetrating ACE inhibitors declined only slightly over the year. The skills of those who took the other drugs declined significantly.

At the beginning of the study, the participants had an average score of about 20 on a memory exam. The memory test scores of those on brain-penetrating ACE inhibitors declined by an average of .6 points.

Meanwhile, the memory test scores of those on non-brain-penetrating ACE inhibitors declined by an average of 4.6 points. The average memory test score decline was 4.9 points for those on calcium channel blockers.

“These brain-penetrating ACE inhibitors might have benefits not only for the prevention but also for the treatment of mild to moderate Alzheimer’s,” said study author Takashi Ohrui, MD, of Tohoku University School of Medicine in Sendai, Japan.

Ohrui and his colleagues were unable to say exactly how the brain-penetrating ACE inhibitors work to slow the cognitive decline in Alzheimer’s, but they speculated that ACE inhibitors may work directly on the renin-angiotensin system in the brain. They noted that the brain’s renin-angiotensin system controls blood pressure and may play an important role in learning and memory processes.

Neurologist David Knopman, MD, of the Mayo Clinic in Rochester, Minn., who wrote an editorial about the study in the journal, said it had several limitations.

Knopman said the participants knew which drug they received, and the researchers were not blinded to which participants received which drug. Blind studies are considered more scientifically accurate because they protect against bias, he noted.

Another weakness to the study, according to Knopman, is the inability to tell whether one of the brain-penetrating ACE inhibitors was more effective than the other in slowing the effects of Alzheimer’s disease.

Source: Medical Week staff, week of October 16, 2004