The scientific journal "Neuron" explained that the study showed that high blood pressure begins to damage the brain before any obvious symptoms appear in a person.
To simulate high blood pressure, the researchers used the hormone angiotensin II, which regulates blood pressure, and injected it into mice. They then analyzed 80,000 cells in the mice's cerebral cortex using single-cell RNA sequencing technology, at two stages: three days after the start of hormone exposure, and 42 days later when cognitive impairments appeared.
The results were surprising: on the third day, although blood pressure was completely normal, brain changes began to appear, where:
The endothelial cells began to "age prematurely" and lost their ability to maintain the vascular barrier.
The activity of the innervation neurons , which are responsible for the balance between excitation and inhibition in the brain, has decreased , leading to a disruption in neural networks.
The precursor cells of oligodendrocytes stopped maturing, which affected the formation of the protective myelin sheaths of the nerves.
By day 42, the symptoms in the mice had worsened, where:
The speed of nerve signal transmission decreased .
A malfunction in the function of mitochondria within nerve cells has appeared.
Cognitive disturbances have become clearly evident.
The study authors confirmed that brain damage does not result from high blood pressure itself, but rather from the direct effect of angiotensin II on brain cells, which explains the development of cognitive impairment in patients with high blood pressure even when their blood pressure readings are moderate.
Researchers believe this discovery will open the door to new strategies for the early detection and prevention of dementia and cognitive diseases associated with high blood pressure.