By Amy Norton
MONDAY, June 17, 2019 (HealthDay News) – A small clinical trial found that treatment with high blood pressure medication could improve blood flow to a key brain region of people with Alzheimer's disease .
The researchers pointed out that they did not know if brain discovery could translate into benefits for patients. But future studies should consider this possibility, they said.
The results, published June 17 in the journal Hypertension, come from an essay on 44 patients with mild to moderate Alzheimer's disease. They were randomly assigned to nilvadipine, a medication for high blood pressure, or to an inactive placebo for six months.
In the end, patients taking this drug showed a 20% increase in blood flow to the hippocampus – a brain structure involved in memory and learning that is one of the first areas damaged by Alzheimer's disease.
Experts said the study was too small and too short to know if improving blood flow could affect symptoms.
But future research should attempt to answer this question and target people with an early form of Alzheimer's disease, said Dr. Jurgen Claassen, lead author of the study.
The research is part of a larger trial to determine if nilvadipine could improve the memory and thinking skills of patients with Alzheimer's disease. Overall, there was no evidence that the drug had helped.
But, Claassen explained, patients with early Alzheimer's showed signs of benefit.
"Thus, a new trial should target these patients and follow them longer – at least two to three years," said Claassen, associate professor at the Radboud University Medical Center in the Netherlands.
According to Rebecca Edelmayer, director of scientific engagement at the Alzheimer's Association, these findings add to a body of evidence about the heart-brain connection.
Research has shown that some of the same risk factors for heart disease, including hypertension, diabetes, and obesity, are also risk factors for dementia. According to Edelmayer, a major trial last year revealed that tight control of high blood pressure reduces the risk of developing mild cognitive impairment in the elderly, a precursor to dementia.
But little is known about the effects of blood pressure control in people already suffering from Alzheimer's disease. And that's why new discoveries must be followed, Edelmayer said.
"We do not know if [blood pressure control] may be more of a preventive measure, or whether it could also play a role in treatment, "she said.
Why is blood pressure important in Alzheimer's disease? According to Claassen, if high blood pressure damages the blood vessels supplying the brain, this could increase cell dysfunction.
Brain cells need a large amount of oxygen and sugar to function well, explained Claassen. So, about 15% to 20% of the body's blood flow goes to the brain, he noted.
In theory, says Claassen, better circulation to the hippocampus could allow its cells to function better even in people with early Alzheimer's disease. But this trial does not prove it.
The study, funded by the government and foundations, involved 44 Alzheimer's patients aged approximately 73 years on average. Half were randomly assigned to take nilvadipine for six months, while the other half received a placebo.
Unsurprisingly, true drug patients saw their blood pressure drop by about 11 points compared to the placebo group.
At the same time, specialized MRI examinations showed that blood flow to the hippocampus increased by 20% on average in the nilvadipine group. He remained stable in other parts of the brain.
For the moment, according to Claassen, the results suggest that the treatment of high blood pressure in patients with Alzheimer's disease is not only safe, but can even increase blood supply to the brain .
But is there any effect of the drug or better control of blood pressure in general? This is not clear from this lawsuit, Claassen said.
"Personally," he added, "I think it's the blood pressure that's going down." That would mean that a drop in blood pressure in any way – including diet and exercise – could have this effect. "
For Edelmayer, the central message is that people "nowadays have tools" to preserve their brain health.
"Heart health is also very important to protect your brain," she said.