Hypertension affects the brain ‘much earlier than expected’

PRESSURE: A study has found patients with hypertension have a higher risk of developing cognitive disorders than people without the condition, but exactly why is not understood…

By Own Correspondent

Hypertension impairs blood vessels, neurons and white matter in the brain well before the condition causes a measurable rise in blood pressure, according to a new preclinical study from Weill Cornell Medicine investigators.

The changes help explain why hypertension is a major risk factor for developing cognitive disorders, such as vascular cognitive impairment and Alzheimer’s disease.

The preclinical findings, published November 14 in Neuron, reveal that hypertension may induce early gene expression changes in individual brain cells that could interfere with thinking and memory. The findings may lead to medications that both reduce blood pressure and prevent cognitive decline.

Patients with hypertension have a 1.2 to 1.5-fold higher risk of developing cognitive disorders than people without the condition, but exactly why is not understood.

While many current hypertension medications successfully lower high blood pressure, they often show little or no effect on brain function. This suggests blood vessel changes could cause damage independently of the elevated pressure associated with hypertension.

“We found that the major cells responsible for cognitive impairment were affected just three days after inducing hypertension in mice—before blood pressure increased,” said senior author Costantino Iadecola, director of the Feil Family Brain and Mind Research Institute, professor of neuroscience and Anne Parrish Titzell Professor of Neurology at Weill Cornell.

“The bottom line is something beyond the dysregulation of blood pressure is involved.”

In previous work, Iadecola’s team found that hypertension affects the function of neurons globally, but recent innovations in single-cell technologies have allowed them to zero in on what is happening in the different types of cells in the brain at the molecular level.

To induce hypertension in mice, the researchers administered the hormone angiotensin, which raises blood pressure, mimicking what happens in humans.

Then, they looked at how different types of brain cells were impacted three days later (before blood pressure increased) and after 42 days (when blood pressure was high, and cognition was affected).