Through a string of interesting studies scientists have been able to probe the links between blood flow to the brain and declining cognitive function. One particularly promising and recent example demonstrated how a drug commonly used for high blood pressure could be used to treat diseases like Parkinson's and dementia. Scientists in the Netherlands have now uncovered another candidate, finding an existing drug used for hypertension was able to boost blood flow to memory and learning regions in the brains of Alzheimer's patients.

The research was carried out by scientists at Radboud University Medical Center and centers on a commonly used hypertension drug called nilvadipine. The drug is a calcium channel blocker and has been used to treat high blood pressure since the 1990s, but recently scientists have started to explore how its effects could benefit patients with Alzheimer's disease, spurred on by earlier research linking declines in brain blood flow with the early stages of the disease.

Enlisting 44 Alzheimer's patients for their study, the researchers divided the participants into two groups, with one group given nilvadipine and the other given a placebo over a period of six months. Measurements of blood flow to the brain's hippocampus were taken via MRI both before and after the treatment began.

The team found that the hypertension drug led to an increase in blood flow of 20 percent to the hippocampus, the brain region responsible for memory and learning. While positive, the scientists urge caution regarding these early results, noting that the sample size is small and the follow-up time relatively short, offering too small a window to make meaningful measurements on structural differences in the brain and cognitive function.

Between 2013 and 2015, another research project involving 500 participants sought to explore whether nilvadipine could slow the onset of Alzheimer's, with the authors concluding there was no clinical benefit for mild to moderate sufferers. But the Radboud team notes that this earlier study did not involve the measurements of blood flow to the brain, and that their research therefore gives new hope to the idea of adapting the hypertension drug to treat the disease. They plan to conduct further research to explore whether these results can be replicated in larger studies, and how they could one day translate to clinical benefits.

"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," says study lead author Jurgen Claassen.

The research was published in the journal Hypertension.