Big-hearted snakes offer clues to healing humans

Snakes get a bad rap for being slimy, cold-hearted creatures, but US researchers said Thursday some actually have huge hearts that could offer clues to treating people with cardiac disease. The secret to the giant Burmese python's success is in a massive amount of fatty acids that circulate in the snake's blood after eating a meal, which could be as big as a deer, according to the study in the journal Science. Scientists at the University of Colorado at Boulder found that as the snake starts digesting its catch, natural oils and fats called triglycerides spike by more than 50 times the usual level. But there is no fat deposited in the snake's heart, due to the activation of a key enzyme that protects the thumping organ as it grows in mass by as much as 40 percent in the first few days after a meal. Scientists identified the chemical composition of the python's blood after eating, and injected either the fed python's plasma or a mixture devised to imitate it into pythons that were fasting. "In both cases, the pythons showed increased heart growth and indicators of cardiac health," said the study, noting that Burmese pythons are as thick as a telephone pole, grow to around 27 feet (eight meters) long and can go without food for up to a year. Researchers then tried the experiment on mice, and found that mice injected with either fed python plasma or the fatty acid mixture showed the same results. "It was remarkable that the fatty acids identified in the plasma-fed pythons could actually stimulate healthy heart growth in mice," said researcher Brooke Harrison. Researcher Cecilia Riquelme said the next step is to figure out how the concoction works so that it may be one day adapted for use in people. "Now we are trying to understand the molecular mechanisms behind the process in hopes that the results might lead to new therapies to improve heart disease conditions in humans," she said. Not all heart growth is good. Conditions like hypertrophic cardiomyopathy, in which the heart muscle thickens and can lead to sudden death in young athletes, is one example. However, the kind of heart growth exhibited by most elite athletes is a reflection of their superior cardiac health. "Well-conditioned athletes like Olympic swimmer Michael Phelps and cyclist Lance Armstrong have huge hearts," said Leslie Leinwand, a professor in the molecular, cellular and developmental biology department and leader of the study. "But there are many people who are unable to exercise because of existing heart disease, so it would be nice to develop some kind of a treatment to promote the beneficial growth of heart cells." The trio of fatty acids identified in the snake's blood were myristic acid, palmitic acid and palmitoleic acid. The enzyme that protected their hearts was superoxide dismutase, which also exists in humans. "We are trying to understand how to make those signals tell individual heart cells whether they are going down a road that has pathological consequences, like disease or beneficial consequences, like exercise," Leinwand said.