Python’s heart-restoring elixir works in mice

Chemical brew used by snakes to build cardiac muscle could help humans

Maybe there’s something to snake oil after all. A mix of compounds called fatty acids identified in pythons can spur an exercise-like boost in the size of mouse hearts.

BIG-HEARTED A Burmese python lets its organs shrivel between meals and re-enlarges them for the next feast with a chemical signal in its blood that turns out to work in lab mice also. Stephen M. Secor

In a test of basic biology, the three fatty acids identified in the blood of Burmese pythons boosted the mass of a heart chamber in lab mice by 10 percent in just a week, researchers report in the Oct. 28 Science. The snakes naturally enlarge their own hearts by some 40 percent in two to three days after eating one of their huge but rare meals. Between meals, python hearts and many other organs shrivel again.

Enlarging heart tissue can be a danger sign for humans. Yet the growth seen in the mice looks more like an athlete’s healthful heart growth than a heart disease patient’s worrisome one, says research leader Leslie A. Leinwand of the University of Colorado Boulder. “We used the extreme biology of a snake to create a beneficial type of cardiac enlargement in mammals,” she says.

Mice, unlike pythons, nibble food steadily and thus shouldn’t need sudden heart growth to cope with huge, rare feasts, says Gerald Dorn of Washington University Medical School in St. Louis, a cardiologist who studies the molecular processes of heart enlargement. So the mouse response in the new study suggests that the research team has uncovered some central stimulating factor common across species, Dorn says. The study is “incredibly promising,” he says.

Leinwand and her colleagues had hoped their snake research would reveal clues to possible medical therapies for people with heart disease. However, many questions remain about how the snakes’ fatty acids actually work to trigger heart muscle cells to bulge. Seeing if they lead to therapies “will take a very long time,” she cautions.

When Leinwand started to set up the study of pythons in 2005, plenty of colleagues thought she’d gone crazy, she remembers. And she says that she later found out that one of the early recruits to her lab staff had a deep-seated horror of snakes.

Despite her antipathy, that recruit, Cecilia Riquelme, now a coauthor of the new study, tried a critical early experiment: She exposed mouse heart cells to extracts of snake blood and saw growth in the cells. “I don’t know whether I literally jumped up and down,” Leinwand says, but she remembers the results as a real eureka moment.

With a lot more experimentation, the Colorado team and colleagues at the University of Alabama in Tuscaloosa determined that the trigger in the snakes’ blood came from a particular combination of fatty acids. These ubiquitous compounds perform a variety of functions in reptiles and humans alike. Just the right mix of three of them — myristic, palmitic and palmitoleic acid — turns out to trigger a quick upsizing in heart muscle cells.

Humans and other mammals produce these three fatty acids in some amounts, says pharmacologist Daniele Piomelli of the University of California, Irvine. And earlier research has suggested a role for one of these fatty acids in insulin activity and protection from fat accumulation. Piomelli calls the python mechanism discovery “remarkable.”

Susan Milius is the life sciences writer, covering organismal biology and evolution, and has a special passion for plants, fungi and invertebrates. She studied biology and English literature.

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