Unexpected, Important Player In Hypertension: The Immune System

New treatment possibilities emerge as it becomes clear that activated immune cells play role in high blood pressure

Could targeting the immune system end up the treatment for hypertension?
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New treatment possibilities emerge as it becomes clear that activated immune cells play role in high blood pressure

Scientists consider targeting immune cells as a revolutionary way to fight hypertension. Vascular biologist David Harrison of the Vanderbilt University School of Medicine in Nashville and his team revealed that they might have devised an innovative new way to treat human hypertension. It started with an experiment on mice.

After giving mice high blood pressure by giving them a dose of the hormone angiotensin II, they turned around and treated the hypertension. How? They mixed a molecule, known as 2-HOBA, into the mice’s drinking water. Once they drank the water, their blood pressure returned to normal.

This molecule comes from buckwheat, and it works by influencing immune cells.

“The immune system is an unexpected but important player in hypertension,” UK vascular biologist Tomasz Guzik of the University of Glasgow said, according to Science Magazine.

They believe that immune cells actually drive up blood pressure with the help of stress and salt. They believe that if they can restrain the immune system in the way the 2-HOBA restrained the immune system in mice, that they might be able to successfully treat hypertension in humans. Safety tests are already in the works to consider the molecule as a viable treatment for high blood pressure in humans. A full clinical trial is Harrison’s next step. Harrison holds the patent on the use of 2-HOBA for the treatment of hypertension.

Current hypertension treatments don’t help as many as one-fifth of all patients. Hypertension often promotes kidney damage, dementia, strokes, and heart attacks. It’s a major, indirect killer.

Scientists say that the immune system affects hypertension.
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Vascular biologist Grant Drummond of La Trobe University in Melbourne, Australia told Science Magazine that it’s pretty clear we aren’t treating hypertension effectively right now with our current methods. What’s interesting is that scientists suggested a link between the immune system and high blood pressure over 50 years ago. Yet, it wasn’t until a 2007 study by Harrison, Guzik, and colleagues that they learned that when angiotensin II was infused into mice that had been genetically altered to be void of B cells and T cells that it began to make sense. When the immune cells were lacking, the mice exhibited blood pressure a solid 20 points below the control mice also given angiotensin II. Plus, when the T cells were restored, their blood pressure skyrocketed. That was the major turning point that eventually led to the current, more specific research.

Still, they don’t actually think that the immune system instigates the hypertension. They think that stress and dietary salt set off the initial increase in blood pressure. Then, they think the immune cells rush in to try to repair the damage, but that sparks a vicious circle.

Harrison said that the puzzle has been the question of what turns on the immune cells in the first place. A few years ago, the same experts think that they isolated the one signal. They think that isoketals, a type of oxidized lipids, adhere to and damage proteins. They realized that the injured proteins stimulate immune cells that turn around and activate T cells. So, they think that the 2-HOBA works by stopping the isoketals in their tracks.

The question on almost everyone’s mind of course is this: Would this approach make patients susceptible to bacteria and viruses? After all, our immune system is pretty important. The scientists think that simply muzzling the reactive ends of the isoketals won’t impair defenses, unlike if they used powerful immune-suppressing drugs like they use for Crohn’s disease and rheumatoid arthritis.