Cold blooded killer with a big heart

Sometimes you hear things that just make you think, ‘The world is too awesome!’

Intrigued by something I had heard on a podcast, I downloaded an article which appeared in Science in October. The above exclamation was uttered when I came across this section:

“The infrequently feeding Burmese python (Python molurus) has been described as a model of extreme metabolic regulation in which many organs, including the heart, increase in mass after a large meal…. The python heart grows in mass by 40% within 48 to 72 hours after consumption of a large meal.”

Wow!

The ability to change the size of the heart is not unique to pythons; our own hearts can grow in response to disease or exercise. However, the speed at which the pythons’ grow is truly astonishing.

The reason that pythons’ hearts enlarge after eating is due to cellular hypertrophy. Or, in lay terms, the cells in the heart get bigger. The paper in which the above extract appeared sought to find the mechanisms behind this remarkable growth.

The researchers observed that, after the python had eaten, there was a massive increase in the numbers of fat particles in the plasma of the snake’s blood. Usually an increase of this size would result in fat accumulation in places around the body, such as the heart. But, in the python, this was not seen.

This suggested that the high fat content of the blood may actually be acting as a trigger for heart cell growth. One of the ways this was tested was by bathing myocytes, heart cells, taken from mice in plasma extracted from a snake after it had fed. Amazingly, the mice myocytes grew!

On further analysis, and testing in live mice and pythons, the group reached the conclusion that a specific combination of 3 types of fat in the python’s blood after eating acts as a trigger which alters gene expression in heart cells, resulting in their growth.

I think that this is an amazing physiological adaptation that the snake has made to cope with infrequent, yet large, meals. Nature is incredible!

 

Source: Riquelme et al (2011) Fatty Acids Identified in the Burmese Python Promote Beneficial Cardiac Growth. Science 334 (6055): 528-531

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