Mammals Can Breathe Through Anus In An Emergency, Japanese Study Finds

Do not smile, because this study showing that it is possible for mammals to absorb oxygen through their anus, conducted by researchers at the Medical and Dental University in Tokyo, could one day help humans in distress. respiratory equipment, for example during a shortage of ventilators, as was the case during the Covid-19 pandemic, or when these machines do not prove to be suitable for a patient.

In principle, breathing involves inhaling oxygen and exhaling carbon dioxide through the lungs or gills. But researchers were intrigued by how animals breathe through their intestines in an emergency. This is the case with certain fish, spiders or even sea cucumbers which can use their posterior to oxygenate themselves in order to survive in emergency situations. And researchers at Tokyo's Medical and Dental University have proven that the same is possible, under experimental conditions, in mice, rats and pigs.

According to their work, published in the journal Med, "the rectum has a mesh of fine blood vessels just below the surface of its wall, which means that drugs delivered through the anus are easily absorbed into the bloodstream," explains Dr. lead author of the study, Ryo Okabe.

It is on this principle that suppositories are based.

The team of scientists therefore wondered if oxygen could be administered in the same way.

"It's a provocative idea"

Two methods were tested: delivering oxygen in the form of gas or by performing an enema rich in oxygen. Scientists in the first case prepared the walls of the rectum by friction, in order to cause inflammation and increase blood flow, which improves the efficiency of the delivery of oxygen. However, since such a treatment would not be accepted in humans, they also used an oxygen-enriched liquid, perfluorodecalin, which is known to be harmless.

As a result, the oxygen delivered in both gas and liquid form increased oxygenation, normalized animal behavior, and extended their lifespan.

The researchers also said that the small proportion of liquid absorbed along with the oxygen did not cause any harmful effects and did not disturb the gut bacteria, indicating that the method was safe.

“Patients in respiratory distress could have their oxygen needs provided by this method while their disease is being treated,” said one of the study's co-authors, Takanori Takebe.

Caleb Kelly of Yale University School of Medicine in the United States stressed that this technique should be taken seriously. "It's a provocative idea and those who discover it for the first time will be surprised," he explained, adding that this "promising therapy deserves the interest of the scientific and medical community. "