Top Story: November 1, 2011

Snake-Hearted

Python_heart

Today, @KQEDscience tweeted:

Giant Rogue Python Swallows Deer Whole

It’s a link to a LiveScience article about a python in Florida doing just that. And it’s not unusual. Adult Burmese pythons can get as big around as telephone poles and grow to 27 feet long. They can eat prey as large as the aforementioned deer, sustaining the snake for months at a time.

When the pythons eat prey this large, interesting things happen to their insides. Their internal organs enlarge. In fact, previous studies show that the hearts of Burmese pythons can grow in mass by 40 percent within 24 to 72 hours after a large meal, and that metabolism immediately after swallowing prey can shoot up by fortyfold. (The snake’s heart goes back to normal size after a few days.)

According to ScienceNOW, this has long fascinated researchers.

Turning weak mammalian hearts into something similar to the pythons' behemoths has been the longtime goal of many biomedical researchers. Bigger, stronger hearts can improve the flow of blood in people with cardiac disease.

Human hearts can grow—in both good and bad ways, says Leslie Leinwand, a cardiology researcher with the University of Colorado and the Howard Hughes Medical Institute. Although cardiac diseases can cause human heart muscle to thicken, heart enlargement from exercise is generally beneficial.

“Well-conditioned athletes like Olympic swimmer Michael Phelps and cyclist Lance Armstrong have huge hearts,” she states. “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.”

Enter the python heart. Leinwand set up experiments in her lab to test python heart growth. Her team confirmed that something in the blood plasma of pythons was inducing positive cardiac growth. They then began looking for specific changes by analyzing proteins, lipids, nucleic acids and peptides present in the fed plasma.

They used a technique known as gas chromatography to analyze both fasted and fed python blood plasma, eventually identifying a highly complex composition of circulating fatty acids with distinct patterns of abundance over the course of the digestive process.

The researchers then tested the fed-python composition on a fasting python and the fasting python’s heart grew, without eating anything.

Next, the team tried the mixture on mice. The animals were hooked up to “mini-pumps” that delivered low doses of the fatty acid mixture over a period of a week. Not only did the mouse hearts show significant growth in the major part of the heart that pumps blood, but the heart muscle cell size increased, without showing an increase in heart fibrosis—which makes the heart muscle more stiff and can be a sign of disease. There were also no alterations in the liver or in the skeletal muscles.

“It was remarkable that the fatty acids identified in the plasma-fed pythons could actually stimulate healthy heart growth in mice,” lab postdoc Brooke Harrison says. The team also tested the fed-python plasma and the fatty acid mixture on cultured rat heart cells, with the same positive results.

Will it have the same effect on humans? More experiments are required. But as the New York Times reports:

…the day may come when doctors literally prescribe snake oil for heart disease.

The research was published last week in Science.

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