Programming the Heart to Survive in Low-Oxygen Environments

In a study that involved juvenile common snapping turtles, researchers have been able to prove that programming the heart to survive the effect of low oxygen is possible.

Turtles are popular for surviving the most extreme conditions. Over the winter, as the oxygen reduces in the pond, causing the environment to become hypoxic.

For most creatures, the low oxygen content is deadly, but not for the snapping turtles. These amphibians often survive the stressful situation by switching their metabolism to one that doesn’t require oxygen.

Thanks to this amazing ability, snapping turtles are uniquely adapted to survive up to six months without oxygen.

Now researchers at the University of Manchester are saying that there’s more to this metabolism switch.

In their paper published in the journal Proceedings of the Royal Society B, the researchers claimed that animals are usually exposed to a low level of oxygen during embryonic development. As a result, their heart became resilient to hypoxia for the rest of their lives.

With these findings, the study suggests that we could develop treatments to reduce damage to the heart caused by hypoxia.

In a statement, co-author of the study and post-doctoral researcher at the University of Manchester, Ilan Ruhr said:

“We’re excited to be the first to show that it is possible to change the degree of tolerance that turtles have for low oxygen environments by early exposure to hypoxia during development.”

Programming the Heart to Survive Hypoxia

Hypoxia usually occurs during a heart attack. It can also damage the heart during heart transplant surgery.

However, early exposure to low-oxygen condition during development can result in epigenetic changes to the genome that controls the gene. That’s why the turtle’s heart cells have a remarkable ability to tolerate zero oxygen conditions.

But, the most interesting part of the study is that the researchers believe that by programming the heart, a person can acquire this ability too.

By isolating the epigenetic signatures that help the turtle survive in a low oxygen environment, the researchers hope to develop drugs. That way, we can switch on our heart’s tolerance to hypoxia at will.

According to Dr. Gina Galli from The University of Manchester:

“Heart cells in turtles and humans are anatomically quite similar, so if we can learn to understand what factors allow them to survive in an oxygen-free environment, we’d hope to be able to apply that to a medical scenario.”

Dr. Galli and her team subjected the turtles to lower oxygen levels while measuring their intracellular pH and calcium. They also recorded the reactive oxygen species, a molecule which can become toxic when the tissue reoxygenates too quickly.

The findings revealed that the amount of reactive oxygen species reduces when the animal is exposed to hypoxia. As a result, their microfilament is not only protected from damage, but it also contracts well in the absence of oxygen.

“A drug which can switch on mechanisms to protect the human heart from oxygen deprivation would be of enormous benefit. It could, for example, protect individuals at risk of heart attack or protect organs for transplantation,” Dr. Galli concluded.