A new study has suggested that one-third of hypertension patients may resist treatment because the condition is not only linked to the kidneys and blood vessels, as long believed, but also originates in the brain.

Researchers reported that excessive salt intake can inflame the brain, triggering hormonal changes that raise blood pressure, a finding that could reshape future approaches to treatment.

The findings, published in Neuron titled “Microglia regulate neuronal activity via structural remodeling of astrocytes,” challenge traditional assumptions about hypertension and point to the brain as a key driver, particularly in cases where patients fail to respond to existing drugs.

The lead researcher of the study, Dr Masha Prager-Khoutorsky, said the study provided fresh evidence that high blood pressure could originate in the brain, opening new doors for therapies targeting brain pathways.

She explained that standard medications, which act mainly on blood vessels and kidneys, remain ineffective for a significant group of patients.
Globally, the World Health Organization (WHO) estimates over 1.4 billion people live with hypertension, or about one in three adults, with two-thirds in low- and middle-income countries.

In Nigeria, prevalence rates vary by region, but a 2020 systematic review estimated a national prevalence of 32.5 per cent in 2020. Although it often shows no symptoms, the condition is a major cause of stroke, heart disease, and other life-threatening complications.

To investigate the effects of salt on blood pressure, researchers gave rats water containing two per cent salt, an amount similar to a diet rich in processed foods such as bacon, instant noodles, and cheese.

They found that this high-salt diet activated immune cells in a specific region of the brain, causing inflammation and increasing levels of vasopressin, a hormone that drives blood pressure higher.

According to Prager-Khoutorsky, the brain’s involvement in hypertension has long been overlooked because of difficulties in studying it. However, she noted that new imaging and laboratory technologies now make it possible to observe such changes directly.

Rats were chosen for the study instead of mice because they regulate salt and water more like humans, making the results more applicable. The team said it now plans to investigate whether similar brain-driven processes are linked to other forms of hypertension.

Hypertension, or high blood pressure, is a condition where the blood vessels have persistently high pressure, defined as a systolic blood pressure (SBP) of 140 mmHg or higher or a diastolic blood pressure (DBP) of 90 mmHg or higher. This condition increases the strain on the heart, raising the risk of serious health problems like heart attacks, strokes, and kidney diseases.