Connection elucidated between obesity, salt sensitivity and high blood pressure

	Tweet

One way obese people become salt sensitive and hypertensive has been identified by Medical College of Georgia researchers.

They’ve documented a chain of events in which excess inflammatory factors resulting from excess fat cause the body to retain more sodium and, consequently, more fluid and higher blood pressure, said Dr. Yanbin Dong, geneticist and cardiologist at MCG’s Georgia Prevention Institute.

Their findings point toward a biomarker in the urine that could one day help physicians identify the most effective therapy for these patients. 

"It’s well established that obesity increases inflammation, salt sensitivity and High Blood Pressure,” said Dong, corresponding author on the study in the American Journal of Physiology Regulatory - Integrative and Comparative Physiology. But there were dots that needed connecting.

Dong’s team outlined the process that appears to start with fat producing more inflammatory factors, such as interleukin-6, or IL-6.

When he and his colleagues exposed mouse kidney cells to IL-6, they found increased production of prostasin, a protease, which typically inhibits a protein’s action by cutting it. But when prostasin cut fellow protein ENaC it increased its activity and so salt reabsorption.

ENaC, or epithelial sodium channel, is the last of many kidney channels that determines how much sodium to excrete. Although ENaC calls the shots on a relatively small amount of sodium, it’s significant in a system that is all about balance, Dong said. “It’s very special; there are not too many proteases like that. We found that in cells fed IL-6, ENaC gets activated and the cells take in more sodium. It is the last step of your salt reabsorption.”

Whether the mouse cell findings are true in humans is tough to answer but it appears measuring prostasis, which is excreted in the urine, may be a way to gauge ENaC activity in humans. Dong already is measuring its levels in obese people with and without hypertension as well as normal-weight individuals. A simple urine test could one day help identify those at risk for or experiencing this type of inflammation-based hypertension, he said.

A number of cholesterol-lowering or antihypertensive agents already on the market – including Statins and angiotensin antagonists – are known to block some aspect of inflammation. Angiotensin antagonists, for example, block production of angiotensin II, which constricts blood vessels and increases IL-6 production. “There may be a good reason to prescribe these types of drugs to obese people,” Dong said.

A 2010 study in the Journal of the American Medical Association said about half the 70 million Americans with High Blood Pressure were keeping it under control by taking medicine and nearly half the people with High Blood Pressure are obese. Twenty percent have diabetes, typically associated with obesity.

###

The research was funded by the National Institutes of Health.

---
Contact: Toni Baker

706-721-4421
Medical College of Georgia

RELATED STORIES:
Drinking black tea may cut blood pressure   Middle-aged men with upper-normal blood pressure at risk for AF   Pollution tied to disease risk in L.A. black women   Birth Defects May be Linked to High Blood Pressure, Not Use of ACE Inhibitors   Poor sleep quality increases risk of high blood pressure   Pilot study suggests new approach to treat preeclampsia   Living with a smoker may raise blood pressure in boys   Vitamin D May Help Explain Racial Differences in Blood Pressure   Research shows blood protein levels may predict risk of a cardiovascular event: Study   Redefining normal blood pressure   New Home Blood Pressure Check Created for Diabetics   Neighborhood Barbers Can Influence Black Men to Seek Blood-Pressure Treatment

Comments

[ + Post Your Own ]

Now you're in the public comment zone. What follows is not Armenian Medical Network's stuff; it comes from other people and we don't vouch for it. A reminder: By using this Web site you agree to accept our Terms of Service. Click here to read the Rules of Engagement.

There are no comments for this entry yet. [ + Comment here + ]