Molecular hub links obesity, heart disease to high blood pressure

April 11, 2013 by Jennifer Brown

(Medical Xpress)—Obesity, heart disease, and high blood pressure (hypertension) are all related, but understanding the molecular pathways that underlie cause and effect is complicated.

A new University of Iowa study identifies a protein within certain as a communications hub for controlling blood pressure, and suggests that abnormal activation of this protein may be a mechanism that links cardiovascular disease and obesity to elevated blood pressure.

"Cardiovascular diseases are the leading cause of death worldwide, and hypertension is a major cardiovascular risk factor," says Kamal Rahmouni, Ph.D., UI associate professor of pharmacology and internal medicine, and senior study author. "Our study identifies the protein called mTORC1 in the hypothalamus as a key player in the control of blood pressure. Targeting mTORC1 pathways may, therefore, be a promising strategy for the management of ."

The hypothalamus is a small region of the brain that is responsible for maintaining normal function for numerous bodily processes, including blood pressure, body temperature, and . Signaling of mTORC1 protein in the hypothalamus has previously been shown to affect food intake and body weight.

The new study, which was published April 2 in the journal Cell Metabolism, shows that the mTORC1 protein is activated by small molecules and hormones that are associated with obesity and cardiovascular disease, and this activation leads to dramatic increases in blood pressure.

Leucine is an amino acid that we get from food, which is known to activate mTORC1. The UI researchers showed that activating mTORC1 in with leucine increased activity in the nerves that connect the brain to the kidney, an important organ in . The increased was accompanied by a rise in blood pressure. Conversely, blocking this mTORC1 activation significantly blunted leucine's blood pressure-raising effect.

This finding may have direct clinical relevance as elevated levels of leucine have been correlated with an increased risk of in patients with cardiovascular disease.

"Our new study suggests a mechanism by which leucine in the bloodstream might increase blood pressure," Rahmouni says.

Previous work has also suggested that mTORC1 is a signaling hub for leptin, a hormone produced by fat cells, which has been implicated in obesity-related hypertension.

Rahmouni and his colleagues showed that leptin activates mTORC1 in a specific part of the hypothalamus causing increased nerve activity and a rise in blood pressure. These effects are blocked by inhibiting activation of mTORC1.

"Our study shows that when this protein is either activated or inhibited in a very specific manner, it can cause dramatic changes in blood pressure," Rahmouni says. "Given the importance of this protein for the control of blood pressure, any abnormality in its activity might explain the hypertension associated with certain conditions like obesity and cardiovascular disease."

Rahmouni and his team hope that uncovering the details of the pathways linking mTORC1 activation and high blood pressure might lead to better treatments for high blood pressure in patients with cardiovascular disease and obesity.

Explore further: Take your blood pressure meds before bed

More information: www.cell.com/cell-metabolism/a … -4131%2813%2900095-8

Related Stories

Take your blood pressure meds before bed

October 24, 2011
It's better to take blood pressure-lowering medications before bed rather than first thing in the morning, according to a study appearing in an upcoming issue of the Journal of the American Society Nephrology (JASN). The ...

Abnormal activation of a protein may explain deadly link between high salt intake and obesity

September 19, 2011
Dietary salt intake and obesity are two important risk factors in the development of high blood pressure. Each packs its own punch, but when combined, they deliver more damage to the heart and kidneys than the sum of their ...

The effect of body mass index on blood pressure varies by race among children

September 21, 2012
Obesity in black children more severely impacts blood pressure than in white children who are equally overweight, according to a new study presented at the American Heart Association's High Blood Pressure Research 2012 Scientific ...

Recommended for you

Want to win at sports? Take a cue from these mighty mice

July 20, 2017
As student athletes hit training fields this summer to gain the competitive edge, a new study shows how the experiences of a tiny mouse can put them on the path to winning.

'Smart' robot technology could give stroke rehab a boost

July 19, 2017
Scientists say they have developed a "smart" robotic harness that might make it easier for people to learn to walk again after a stroke or spinal cord injury.

Engineered liver tissue expands after transplant

July 19, 2017
Many diseases, including cirrhosis and hepatitis, can lead to liver failure. More than 17,000 Americans suffering from these diseases are now waiting for liver transplants, but significantly fewer livers are available.

Lunatic Fringe gene plays key role in the renewable brain

July 19, 2017
The discovery that the brain can generate new cells - about 700 new neurons each day - has triggered investigations to uncover how this process is regulated. Researchers at Baylor College of Medicine and Jan and Dan Duncan ...

New animal models for hepatitis C could pave the way for a vaccine

July 19, 2017
They say that an ounce of prevention is worth a pound of cure. In the case of hepatitis C—a disease that affects nearly 71 million people worldwide, causing cirrhosis and liver cancer if left untreated—it might be worth ...

Omega-3 fatty acids fight inflammation via cannabinoids

July 18, 2017
Chemical compounds called cannabinoids are found in marijuana and also are produced naturally in the body from omega-3 fatty acids. A well-known cannabinoid in marijuana, tetrahydrocannabinol, is responsible for some of its ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

neversaidit
not rated yet Apr 12, 2013
oh ffs. there will not be a single protein found responsible for this. the metabolic system is to complex and with too many redundancies. there will be a multitude of proteins and other elements, that are very responsive to the environment.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.