During the early stages of Alzheimer’s disease (AD), it is known that there is a decrease in cerebral blood flow. This observation has led researchers to examine whether drugs that affect blood pressure could play a role at improving blood flow.
According to a recent study, which has been published in Hypertension, nilvadipine has been demonstrated to increase blood flow to the hippocampus among people with AD without affecting other parts of the brain. Researchers have also indicated that this decrease in blood flow in people with Alzheimer’s may be reversed in some regions of the brain. However, whether this observed increase in cerebral blood flow translates to clinical benefits is yet to be determined.
Within the investigation, scientists examined whether nilvadipine could help treat Alzheimer’s by comparing the use of the drug and a placebo among people with mild-to-moderate AD. The researchers randomly assigned 44 participants to receive either nilvadipine or placebo for 6 months. Neither researchers nor study participants knew who received the drug or placebo.
At the start of the study and at 6 months in, the team measured blood flow to specific regions of the brain using a unique MRI technique. Results indicated that blood flow to the hippocampus increased by 20% among the nilvadipine group compared with the placebo group. In addition to this, it was reported that blood flow to other regions of the brain remained the same.
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The researchers noted that sample sizes were too small and follow-up time too short to reliably study the effects of this cerebral blood flow increase on structural brain measures and cognitive measures.
Investigators of the current study also made note to a larger research project that compared nilvadipine with placebo in more than 500 people with mild-to-moderate AD took place between 2013 and 2015. They stated that the effects on cerebral blood flow were not measured and overall, no clinical benefit was noted with the use of nilvadipine. However, a subgroup of patients with only mild symptoms of disease did show benefit in terms of slower decline in memory.
Previous studies have indicated that high blood pressure treatment could reduce the risk of developing dementia and the authors of the present study believe that the beneficial effects on brain blood flow could explain part of this effect.
Lead author of the study, Jurgen Claassen (Radboud University Medical Center, Nijmegen, The Netherlands), concluded: “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 AD, especially in earlier stages of disease.”
Sources: de Jong DLK, de Heus RAA, Rijpma A et al. Effects of nilvadipine on cerebral blood flow in patients with Alzheimer’s disease. Hypertension doi:10.1161/HYPERTENSIONAHA.119.12892 (2019) (Epub ahead of print); https://newsroom.heart.org/news/hypertension-drug-may-hold-promise-for-alzheimers-disease?preview=6c97