Hypertension Drug Increases Hippocampal Blood Flow in Patients with Alzheimer’s Disease

Cerebrovascular changes, including reduced cerebral blood flow, occur early in the development of Alzheimer’s disease and may accelerate disease progression. In a study published online this week in the journal Hypertension, nilvadipine — a calcium channel blocker used to treat high blood pressure — increased cerebral blood flow in the hippocampus — the brain’s memory and learning center — among people with Alzheimer’s disease without affecting other parts of the brain.

Nilvadipine, a dihydropyridine calcium antagonist that is in use as an antihypertensive agent, increased hippocampal cerebral blood flow (CBF) while lowering blood pressure in people with Alzheimer’s disease. These findings indicate that the known decrease in CBF in Alzheimer’s patients can in some regions be reversed. Image credit: OpenStax College / Anatomy Physiology, cnx.org / CC BY 3.0.

Dr. Jurgen Claassen of Radboud University Medical Center and colleagues sought to discover whether nilvadipine could help treat Alzheimer’s disease by comparing the use of nilvadipine and a placebo among people with mild to moderate Alzheimer’s.

The researchers randomly assigned 44 participants to receive either nilvadipine or a placebo for six months.

At the study’s start and after six months, they measured blood flow to specific regions of the brain using a unique magnetic resonance imaging technique.

The results showed that blood flow to the hippocampus increased by 20% among the nilvadipine group compared to the placebo group.

Blood flow to other regions of the brain was unchanged in both groups.

Systolic blood pressure was reduced on average by 11.5 mm Hg.

“This high blood pressure treatment holds promise as it doesn’t appear to decrease blood flow to the brain, which could cause more harm than benefit,” Dr. Claassen said.

“Even though no medical treatment is without risk, getting treatment for high blood pressure could be important to maintain brain health in patients with Alzheimer’s disease.”

The participants were screened between 2013 and 2015 as part of a larger research project comparing nilvadipine to placebo among more than 500 people with mild to moderate Alzheimer’s disease.

In that larger project, effects on cerebral blood flow were not measured.

Overall, no clinical benefit was noted with use of nilvadipine. However, a subgroup of patients with only mild symptoms of disease did show benefit, in the sense of a slower decline in memory.

“In the future, we need to find out whether the improvement in blood flow, especially in the hippocampus, can be used as a supportive treatment to slow down progression of Alzheimer’s disease, especially in earlier stages of disease,” Dr. Claassen said.

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Daan L.K. de Jong et al. Effects of Nilvadipine on Cerebral Blood Flow in Patients With Alzheimer Disease. A Randomized Trial. Hypertension, published online June 17, 2019; doi: 10.1161/HYPERTENSIONAHA.119.12892