Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fat buildup found in hearts of obese or diabetic heart failure patients

03.11.2004


Diabetic or obese patients suffering advanced heart failure have higher levels of fat embedded in their hearts and greater molecular evidence of haywire cardiac metabolism, a research team led by cardiologists at The University of Texas Medical School at Houston reports in the November issue of the FASEB Journal.



Heart failure, progressive and potentially fatal weakening of the heart muscle, is associated with both obesity and diabetes, but the mechanisms by which damage occurs are not well-understood, said senior author Heinrich Taegtmeyer, M.D., Ph.D., professor of cardiology. "In cardiology, we’ve long been concerned about fat accumulating in the artery walls and blocking the flow of blood to the heart. What we are finding now is that the buildup of fat doesn’t stop in the blood vessels, it’s actually worse in heart muscle cells," Taegtmeyer said. "We also report in this paper that diabetes and obesity appear to cause metabolic irregularities in the heart tissue."

Gene expression and protein findings in the paper provide potential long-term targets for treating heart failure, which afflicts 5 million U.S. patients annually. Researchers examined 27 failing hearts that were removed during transplants and compared them to eight donor hearts that were not failing but were otherwise unsuitable for transplant. Eight of the failing hearts (30 percent) showed high levels of triglycerides – a fat storage and transport molecule. Levels of triglycerides in failing hearts were four times the level in obese or diabetic patients as they were in non-failing hearts.


The research team associated this buildup of triglycerides in the heart muscle, called lipotoxicity, with dysfunctional expression of genes related to the heart’s metabolism of fatty acids, its contractile function, and an inflammatory protein known to contribute to insulin resistance. The human results track with a rat model of the lipotoxic heart, which has been shown to cause improper cardiac contraction in the rodents, said first author Saumya Sharma, M.D., a cardiology fellow and researcher in Taegtmeyer’s lab.

A normal heart derives two-thirds of its energy requirement by metabolizing fatty acids, which are carried in triglycerides, Sharma said. Lipotoxic hearts store some triglycerides in the muscle tissue rather than metabolizing them. In obese people, Taegtmeyer and his team theorize that this occurs because the person’s fat cells, which capture and store excess triglycerides, fill up. Because people have a set number of fat cells, once they are full, excess fat lodges in muscle tissue, where it wreaks molecular havoc. "The heart is a muscle, too, and it’s not spared from this onslaught of fat," Taegtmeyer explained. "The heart is designed to contract, but if lipids (fat) displace its contractile proteins, that results in impaired heart function."

Taegtmeyer and colleagues are testing this hypothesis among obese patients who have elected to have bariatric surgery (surgical reduction of stomach size). Patients in the study volunteer to have their cardiac function analyzed and to provide a small sample of thigh muscle tissue before and after their surgery. Taegtmeyer’s team will then assess whether weight loss after surgery results in improved heart function and decreased levels of lipids in muscle tissue.

Earlier research by Taegtmeyer showed that diabetes causes toxic levels of lipids and glucose to build up in the heart.

Scott Merville | EurekAlert!
Further information:
http://www.uth.tmc.edu

More articles from Health and Medicine:

nachricht NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures
17.11.2017 | National Institute of Standards and Technology (NIST)

nachricht High speed video recording precisely measures blood cell velocity
15.11.2017 | ITMO University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>