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Gut microbes help regulate blood pressure

Last Updated: Wednesday, February 27, 2013 - 17:27

Washington: A new study has suggested that gut bacteria are an integral part of the body`s complex system for maintaining a stable blood pressure.


"The contribution that gut microbes apparently make to blood pressure regulation and human health is a surprise. There is still much to learn about this mechanism, but we now know some of the players and how they interact," said Jennifer Pluznick, Ph.D., assistant professor of physiology at the Johns Hopkins University School of Medicine.

Pluznick said that several years ago, thanks to a "happy coincidence," she found - in the kidney - some of the same odor-sensing proteins that give the nose its powers.

Focusing on one of those proteins, olfactory receptor 78 (Olfr78), her team specifically located it in the major branches of the kidney`s artery and in the smaller arterioles that lead into the kidney`s filtering structures. Olfr78 also turned up in the walls of small blood vessels throughout the body, she said, particularly in the heart, diaphragm, skeletal muscle and skin.




To pinpoint the effect of Olfr78, the scientists gave SCFAs to mice missing the Olfr78 gene and found that the rodents` blood pressure decreased, suggesting that SCFAs normally induce Olfr78 to elevate blood pressure. However, when they gave SCFAs to normal mice with intact Olfr78, they did not see the expected increase in blood pressure, but rather a decrease, though it was less pronounced than before.


The mystery was solved, Pluznick said, when the team examined mice lacking Gpr41, a non-smell-related protein receptor located in blood vessel walls that also binds SCFAs. When SCFAs bind to Gpr41, blood pressure is decreased.

The researchers eventually discovered that Olfr78 and Gpr41 both are activated by SCFAs, but with contradictory effects. The negative effect of Gpr41 is counterbalanced by the positive effect of Olfr78, but Gpr41`s effect is stronger, so an increase in SCFAs produces an overall decrease in blood pressure.

"We don`t have the full story yet. There are many players involved in the maintenance of stable levels of blood pressure, and these are just a few of them," note Pluznick.


A description of the research recently appeared online in the journal Proceedings of the National Academy of Sciences.


First Published: Wednesday, February 27, 2013 - 17:27
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