Snakes with big hearts may help yours: Fatty acids involved in python heart growth could benefit diseased human heart

ScienceDaily (Oct. 27, 2011) — Identification of three fatty acids involved in the extreme growth of Burmese pythons' hearts following large meals could prove beneficial in treating diseased human hearts, according to research co-authored by a University of Alabama scientist and publishing in the Oct. 28 issue of Science.

Growth of the human heart can be beneficial when resulting from exercise -- a type of growth known as physiological cardiac hypertrophy -- but damaging when triggered by disease -- growth known as pathological hypertrophy. The new research shows a potential avenue by which to make the unhealthy heart growth more like the healthy version.

"We may later be able to turn the tables, in a sense, in the processes involved in pathological hypertrophy by administering a combination of fatty acids that occur in very high concentrations in the blood of digesting pythons," said Dr. Stephen Secor, associate professor of biological sciences at UA and one of the paper's co-authors. "This could trigger, perhaps, something more akin to the physiological form of hypertrophy."

The research, conducted in collaboration with multiple researchers at the University of Colorado working in the lab of Dr. Leslie Leinwand, identified three fatty acids, myristic acid, palmitic acid and palmitoleic acid, for their roles in the snakes' healthy heart growths following a meal.

Researchers took these fatty acids from feasting pythons and infused them into fasting pythons. Afterward, those fasting pythons underwent heart-rate growths similar to that of the feasting pythons. In a similar fashion, the researchers were able to induce comparable heart-rate growths in rats, indicating that the fatty acids have a similar effect on the mammalian heart.

The paper, whose lead author was Dr. Cecilia Riquelme of the University of Colorado, also showed that the pythons' heart growth was a result of the individual heart cells growing in size, rather than multiplying in number.

By studying gene expression in the python hearts -- which genes are turned on following feasting -- the research, Secor said, shows that the changes the pythons' hearts undergo is more like the positive changes seen in a marathon runner rather than the types of changes seen in a diseased, or genetically altered, heart.

"Cyclists, marathon runners, rowers, swimmers, they tend to have larger hearts," Secor said. "It's the heart working harder to move blood through it. The term is 'volume overload,' in reference to more blood being pumped to tissues. In response, the heart's chambers get larger, and more blood is pushed out with every contraction, resulting in increased cardiac performance."

However, the time-frame of this increased heart performance of a python blows away even the most physically-fit distance runner, Secor said.

"Instead of experiencing elevated cardiac performance for several hours with running, the Burmese python is maintaining heightened cardiac output for five to six days, non-stop, while digesting their large meal."

Another interesting finding of the research, Secor said, is even with the increased volume of triglycerides circulating in the snakes after feeding, those lipids are not remaining within the snakes' hearts or vascular systems after the completion of digestion.

"The python hearts are using the circulating lipids to fuel the increase in performance."

Traditionally, mice have been the preferred animal model used to study the genetic heart disease known as hypertrophic cardiomyopathy, characterized by heart growth and contractile dysfunction. However, the snakes' unusual physiological responses render them more insightful models, in some cases, Secor said.

Pythons are infrequent feeders, sometimes eating only once or twice a year in the wild. When they do eat, they undergo extreme physiologic and metabolic changes that include increases in the size of the heart, along with the liver, pancreas, small intestine and kidney. Three days after a feeding, a python's heart mass can increase as much as 40 percent, before reverting to its pre-meal size once digestion is completed, Secor said.

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The above story is reprinted from materials provided by University of Alabama in Tuscaloosa.

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Journal Reference:

Cecilia A. Riquelme, Jason A. Magida, Brooke C. Harrison, Christopher E. Wall, Thomas G. Marr, Stephen M. Secor, Leslie A. Leinwand. Fatty Acids Identified in the Burmese Python Promote Beneficial Cardiac Growth. Science, 2011; 334 (6055): 528-531 DOI: 10.1126/science.1210558

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Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

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Highly efficient oxygen catalyst found: Rechargeable batteries and hydrogen-fuel production could benefit

ScienceDaily (Oct. 28, 2011) — A team of researchers at MIT has found one of the most effective catalysts ever discovered for splitting oxygen atoms from water molecules -- a key reaction for advanced energy-storage systems, including electrolyzers, to produce hydrogen fuel and rechargeable batteries. This new catalyst liberates oxygen at more than 10 times the rate of the best previously known catalyst of its type.

The new compound, composed of cobalt, iron and oxygen with other metals, splits oxygen from water (called the Oxygen Evolution Reaction, or OER) at a rate at least an order of magnitude higher than the compound currently considered the gold standard for such reactions, the team says. The compound's high level of activity was predicted from a systematic experimental study that looked at the catalytic activity of 10 known compounds.

The team, which includes materials science and engineering graduate student Jin Suntivich, mechanical engineering graduate student Kevin J. May and professor Yang Shao-Horn, published their results in Science on Oct. 28.

The scientists found that reactivity depended on a specific characteristic: the configuration of the outermost electron of transition metal ions. They were able to use this information to predict the high reactivity of the new compound -- which they then confirmed in lab tests.

"We not only identified a fundamental principle" that governs the OER activity of different compounds, "but also we actually found this new compound" based on that principle, says Shao-Horn, the Gail E. Kendall (1978) Associate Professor of Mechanical Engineering and Materials Science and Engineering.

Many other groups have been searching for more efficient catalysts to speed the splitting of water into hydrogen and oxygen. This reaction is key to the production of hydrogen as a fuel to be used in cars; the operation of some rechargeable batteries, including zinc-air batteries; and to generate electricity in devices called fuel cells. Two catalysts are needed for such a reaction -- one that liberates the hydrogen atoms, and another for the oxygen atoms -- but the oxygen reaction has been the limiting factor in such systems.

Other groups, including one led by MIT's Daniel Nocera, have focused on similar catalysts that can operate -- in a so-called "artificial leaf" -- at low cost in ordinary water. But such reactions can occur with higher efficiency in alkaline solutions, which are required for the best previously known catalyst, iridium oxide, as well as for this new compound.

Shao-Horn and her collaborators are now working with Nocera, integrating their catalyst with his artificial leaf to produce a self-contained system to generate hydrogen and oxygen when placed in an alkaline solution. They will also be exploring different configurations of the catalyst material to better understand the mechanisms involved. Their initial tests used a powder form of the catalyst; now they plan to try thin films to better understand the reactions.

In addition, even though they have already found the highest rate of activity yet seen, they plan to continue searching for even more efficient catalyst materials. "It's our belief that there may be others with even higher activity," Shao-Horn says.

Jens Norskov, a professor of chemical engineering at Stanford University and director of the Suncat Center for Interface Science and Catalysis there, who was not involved in this work, says, "I find this an extremely interesting 'rational design' approach to finding new catalysts for a very important and demanding problem."

The research, which was done in collaboration with visiting professor Hubert A. Gasteiger (currently a professor at the Technische Universität München in Germany) and professor John B. Goodenough from the University of Texas at Austin, was supported by the U.S. Department of Energy's Hydrogen Initiative, the National Science Foundation, the Toyota Motor Corporation and the Chesonis Foundation.

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The above story is reprinted from materials provided by Massachusetts Institute of Technology. The original article was written by David L. Chandler, MIT News Office.

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Journal Reference:

J. Suntivich, K. J. May, H. A. Gasteiger, J. B. Goodenough, Y. Shao-Horn. A Perovskite Oxide Optimized for Oxygen Evolution Catalysis from Molecular Orbital Principles. Science, 2011; DOI: 10.1126/science.1212858

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