“Slower” link between neurons and blood microvessels in hypertensive patients

“Before they have brain damage, vascular dementia and strokes already start [doentes hipertensos e diabéticos] have the connection between neurons and blood microvessels lazier, slower and less intense”, one of the coordinators of the study that the FMUP team carried out in collaboration with researchers from the Northwestern University Feinberg School of Medicine in Chicago. United States, Elsa Azevedo.

This deficit or significant dysfunction of the joint is detectable even in the absence of any symptoms of cerebrovascular disease, specifies the professor of the FMUP.

Elsa Azevedo mentioned that the link between neuronal activity and vascular response is essential to guarantee the normal functioning of the brain.

“Usually it is necessary to increase the blood supply to the most active brain areas at any given time, and this is achieved by the physiological mechanism of neurovascular coupling, i.e. the articulation between neurons and the blood vessels that feed them. This mechanism needs to be fine-tuned for proper brain function,” he explained.

Although he speaks of a “promising” finding, the researcher speculated that further studies would be needed before its routine use in clinical practice.

The goal is to go “beyond” and understand what is causing this brain damage so that we can correct and prevent strokes “as much as possible”, he said.

Hypertensive patients who had never suffered a stroke participated in the study, after being subjected to non-invasive imaging tests, namely transcranial Doppler to analyze the main mechanisms of regulation of cerebral vasoreactivity and the magnetic resonance imaging to assess the volume of white matter lesions in the brain. .

Doppler is a non-invasive test that estimates blood flow through blood vessels using ultrasound that focuses on blood cells.

During visual stimulation, the researchers found that “hypertensive patients have less acceleration of blood flow velocity in the artery supplying the visual cortex, exhibiting a slower response to the increased demands caused by the stimulus, as well as less flexibility in response, “compared to healthy people without high blood pressure,” the researcher said.

In hypertensive and diabetic patients, “outcomes were even worse, indicating early deficits in neurovascular coupling, before the onset of symptoms of cerebrovascular disease,” he added.

Thus, the study shows that diseases such as hypertension and diabetes can negatively affect the brain even before the onset of cerebrovascular diseases, such as strokes or cognitive changes.

FMUP researchers Ana Monteiro, Pedro Castro, Gilberto Pereira, Carmen Ferreira, Jorge Poland and Elsa Azevedo participated in the work, along with Farzaneh Sorond and Andrew Milstead of Northwestern University Feinberg School of Medicine.

The study was published in the journal Frontiers in Aging Neuroscience.

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