Mammals Breathe Through Intestines to Recover From Respiratory Distress; Can Humans Do The Same?

Intestines are part of the digestive system that digests food. But for rodents, pigs, and other mammals, it could also be another way to breathe.

A new study suggests that mice, rats, pigs, and other mammals share a secret superpower. The tissues in their rectum could absorb oxygen to help them recover from respiratory distress.

The scientists behind this discovery propose that flushing oxygen to the rectum could someday help save human lives, such as an alternative treatment for COVID-19 patients.

Crazy Idea

A type of loach fish called Misgurnus anguillicaudatus, common in parts of East Asia, is said to have evolved a long time ago when aquatic environments have scarce light and limited oxygen. This fish breathes air through its posterior. Scientists now report that this unique form o intestinal breathing may not be exclusive to aquatic animals.

"It looks like a crazy idea," says Sean Colgan, a gastroenterologist at the University of Colorado, Boulder, who was not involved in the study. "But if you look at the data, it's actually a very compelling story."

Gastroenterologist Takanori Takebe from Cincinnati Children's Hospital and colleagues tested out several approaches in ventilating intestines of mice and pigs that were deprived briefly of oxygen, Science Magazine reported.

They tried scrubbing the animals' intestines to thin the mucosal lining and improve oxygen absorption and then injected pure, pressurized oxygen into the rectums. After which, they withdrew oxygen from the animals to make them hypoxic.

They found that those mice with unscrubbed intestines and who received no intestinal oxygen survived for a median of 11 minutes, while those unscrubbed mice but received oxygen through their anus lasted for 18 minutes.

On the other hand, only those ventilated mice with brushed intestines lived through an hour with a survival rate of 75%, researchers reported.

Then the team tried using oxygenated liquid instead of gas to ditch the dangerous process of scrubbing the intestines of animals. According to Live Science, the team found similarly promising results as using oxygen gas.

They noted that more work is needed to see if the approach is also applicable to humans. They published their study, "Mammalian enteral ventilation ameliorates respiratory failure," in the journal Med.

Alternative Treatment for COVID-19 Patients

Over the past year when the COVID-19 pandemic started, many patients have been placed on ventilators to undergo ECMO wherein oxygen is pumped into the patient's bloodstream using a machine. However, there was a time when ECMO machines fell short in supply, leading to many casualties.

Some scientists believe that that the recent discovery of intestinal breathing in some mammals, facilitated by external ventilation, could hopefully work as an alternative treatment for COVID-19 patients, Inverse reported.

"We can potentially develop a new medical device, aimed at increasing oxygen level in humans," Takebe says. "If granted, clinicians can explore the option to support respiratory complications associated with many infectious diseases including COVID-19."

But before that, intestinal breathing needs further study before it could be implemented in treating humans who are suffering from respiratory distress.

Check out more news and information on the Animals in Science Times.