Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High blood pressure induces low fat metabolism in heart muscle

08.08.2006
"The heart is the single most energy-consuming organ per weight in the body," says Lisa de las Fuentes, M.D.

Under some conditions this energy-hungry organ is prone to defects in its energy metabolism that contribute to heart disease, according to research published in a recent issue of the Journal of Nuclear Cardiology by de las Fuentes and colleagues at Washington University School of Medicine in St. Louis.

Earlier research led by de las Fuentes' colleague Robert J. Gropler, M.D., showed that heart muscle in people with diabetes is overly dependent on fat for energy. Even though fat is an efficient fuel, burning it for energy creates an unusually high demand for oxygen, making the diabetic heart more sensitive to the drops in oxygen levels that occur with coronary artery blockage.

Gropler is director of the Cardiovascular Imaging Laboratory at the Mallinckrodt Institute of Radiology at the School of Medicine and professor of radiology, medicine and biomedical engineering.

Now this group of Washington University researchers has shown that hearts of non-diabetics with muscle thickening due to high blood pressure have an energy metabolism skewed in the opposite direction -- away from the use of fat for energy.

"Whereas Dr. Gropler found that a high level of fatty acid metabolism could be detrimental, we show that a low level may also be harmful," says de las Fuentes, co-director of the Cardiovascular Imaging and Clinical Research Core Laboratory and assistant professor of medicine. "These findings aren't contradictory. The heart has to be able to choose the energy source, either fats or glucose, most appropriate for its current energy needs and the availability of fuel."

De las Fuentes explains that hearts with muscle thickening, or hypertrophy, get less energy because of their reduced fat metabolism, which leads them to rely more heavily on carbohydrates.

"Carbohydrates produce less energy per molecule than fatty acids," she says. "With hypertrophy, the heart has a higher energy demand because there's more muscle to feed. With less fat metabolism, a greater reliance on carbohydrates may represent a shift to a less-efficient fuel."

The metabolic abnormality can eventually lead to impaired contraction of the heart and to heart failure.

Animal studies by collaborators at Washington University have shown that in mice with thickened heart muscle, genes associated with transporting and breaking down fatty acids are less active than normal -- in other words, the heart's fat-burning machinery is malfunctioning.

In this human study, the researchers studied patients who had high blood pressure that resulted in hypertrophy of the muscle of the left ventricle, the chamber of the heart that pumps blood to the body. The study showed that the greater the muscle mass of the hypertrophic heart, the lower the ability to burn fat. Magnetic resonance scans suggested that hypertrophic heart muscle had subtle abnormalities in contractile function at rest and was less energy efficient.

Normally heart muscle will alter between using fats and carbohydrates as fuel depending on availability. But at times of the day when blood glucose is low -- such as when a person hasn't eaten in a while -- hypertrophic hearts can't switch to burning fatty acids as normal hearts would, possibly leaving them energy deficient, de las Fuentes explains.

"This is the first time these data have been shown in humans," says senior author Victor G. Dávila-Román, M.D., director of the Cardiovascular Imaging and Clinical Research Core Laboratory and professor of medicine, anesthesiology and radiology. "That is particularly significant because hypertension (high blood pressure) is a huge public health problem in the United States. Of the 65 million people with hypertension, between 25 and 50 percent of them have some evidence that their heart has been affected by high blood pressure."

Not everyone who has high blood pressure will develop hypertrophy, and not everyone with hypertrophy has long-term problems, according to de las Fuentes. Some people appear to be protected while others appear to be at increased risk, likely due to genetic factors.

"Because we have this evidence that shows that fatty acid metabolism may play a role in this process, we are looking for variations in the metabolism genes in an ongoing clinical study," de las Fuentes says.

Dávila-Román adds that by looking at the genetics of hypertension and hypertensive heart disease, they hope to identify genes that predispose people to both good and bad traits associated with these disorders. Such information promises opportunities for both prevention and treatment of cardiac disease.

Gwen Ericson | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Health and Medicine:

nachricht Biofilm discovery suggests new way to prevent dangerous infections
23.05.2017 | University of Texas at Austin

nachricht Another reason to exercise: Burning bone fat -- a key to better bone health
19.05.2017 | University of North Carolina Health Care

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 quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>