Nav: Home

Angiotensin receptor blockers normalize sodium excretion

November 13, 2018

AUGUSTA, Ga. (Nov. 13, 2018) - Drugs that inhibit a hormone that constricts blood vessels also help improve sodium excretion in blacks who hold onto too much sodium in the face of stress, investigators report.

The drugs are angiotensin receptor blockers and the study appears to be the first to look at their impact on sodium excretion in sodium retainers, investigators report in the journal Ethnicity & Disease.

It's also some of the first evidence in humans that the innate system that enables us to flee danger may itself be dangerous to our cardiovascular health. And, that targeting that system may be an effective strategy for some high blood pressure patients.

"This puts the pieces together and opens up the opportunity for a better treatment strategy for individuals who are sodium retainers and who, like most of us, often find themselves stressed," says Dr. Gregory Harshfield, director of the Georgia Prevention Institute at the Medical College of Georgia at Augusta University.

Harshfield, corresponding author on the new study, has previously shown that about 30 percent of blacks and 15 percent of whites hold onto more salt - about the same amount found in a serving of fast food French fries - than others in response to stress. They continue to hold onto it after the stress that activated their innate protective system has passed, which can drive daytime blood pressures up and keep nighttime pressures too high as well.

He's been looking for more answers about why and treatment strategies that target the problem.

Sodium retention is regulated by the kidneys and a natural way the body responds to stress. It's part of the fight-or-flight survival mechanism that gets the heart pounding and the body moving quickly when needed, Harshfield says. But as with most things, too much can be bad.

Studies in lab animals with a propensity for too much sodium retention indicate the reaction starts with stress activating the sympathetic nervous system in the kidneys, increasing the amount of sodium the kidneys retain rather than excrete.

One way it does this is by activating angiotensin II, a stress hormone and powerful constrictor of blood vessels, which in turn activates aldosterone, a hormone that prompts the kidneys to hold onto sodium. Like stress, obesity also can set this unhealthy chain of events into motion.

The study looked at 87 healthy blacks ages 18 to 50. While none of the participants were hypertensive at the time of the study, the investigators documented that 25 of the participants held onto more sodium with stress.

For seven days, participants received either a placebo or irbesartan, an angiotensin II receptor blocker currently prescribed alone or in combination with other drugs to treat high blood pressure. It's also used to treat kidney disease in patients with diabetes.

To produce mild mental stress, participants played a video game that offered a cash reward.

Investigators found that treatment with irbesartan improved sodium excretion in the sodium retainers during both stress and rest.

Systolic blood pressure, the pressure inside blood vessels when the heart beats, was actually decreased about five points during stress in the retainers following treatment with the angiotensin receptor blocker.

The drug did not significantly impact sodium excretion in the non-retainers.

Similar studies are needed in black and white individuals who already are hypertensive and hold onto too much sodium, Harshfield says.

One in three American adults have hypertension, according to the Centers for Disease Control and Prevention, and only about half of those individuals have their blood pressure under control. High blood pressure puts you at risk for heart disease and stroke, which are leading causes of death in the United States. A blood pressure of less than 120/80 millimeters of mercury is considered normal, according to the CDC and American Heart Association.
-end-
Harshfield is vice chair of the MCG Department of Population Health Sciences. The research was funded by the National Institutes of Health.

See the study here https://www.ethndis.org/edonline/index.php/ethndis/article/view/883.

Medical College of Georgia at Augusta University

Related Blood Pressure Articles:

Brain blood flow sensor discovery could aid treatments for high blood pressure & dementia
A study led by researchers at UCL has discovered the mechanism that allows the brain to monitor its own blood supply, a finding in rats which may help to find new treatments for human conditions including hypertension (high blood pressure) and dementia.
Here's something that will raise your blood pressure
The apelin receptor (APJ) has been presumed to play an important role in the contraction of blood vessels involved in blood pressure regulation.
New strategy for treating high blood pressure
The key to treating blood pressure might lie in people who are 'resistant' to developing high blood pressure even when they eat high salt diets, shows new research published today in Experimental Physiology.
Arm cuff blood pressure measurements may fall short for predicting heart disease risk in some people with resistant high blood pressure
A measurement of central blood pressure in people with difficult-to-treat high blood pressure could help reduce risk of heart disease better than traditional arm cuff readings for some patients, according to preliminary research presented at the American Heart Association's Hypertension 2019 Scientific Sessions.
Heating pads may lower blood pressure in people with high blood pressure when lying down
In people with supine hypertension due to autonomic failure, a condition that increases blood pressure when lying down, overnight heat therapy significantly decreased systolic blood pressure compared to a placebo.
The Lancet Neurology: High blood pressure and rising blood pressure between ages 36-53 are associated with smaller brain volume and white matter lesions in later years
A study of the world's oldest, continuously-studied birth cohort tracked blood pressure from early adulthood through to late life and explored its influence on brain pathologies detected using brain scanning in their early 70s.
Blood pressure control is beneficial, is it not?
Until recently, physicians had generally assumed that older adults benefit from keeping their blood pressure below 140/90 mmHg.
The 'blue' in blueberries can help lower blood pressure
A new study published in the Journal of Gerontology Series A has found that eating 200g of blueberries every day for a month can lead to an improvement in blood vessel function and a decrease in systolic blood pressure in healthy people.
How to classify high blood pressure in pregnancy?
The American Heart Association (AHA) and the American College of Cardiology (ACC) changed their guidance to lower the threshold criteria for hypertension in adults.
Discovery could advance blood pressure treatments
A team of Vanderbilt University Medical Center researchers, working with the US Department of Veteran's Affairs (VA), has discovered genetic associations with blood pressure that could guide future treatments for patients with hypertension.
More Blood Pressure News and Blood Pressure Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.