Science has known for decades that certain aquatic species such as cobitids (or loaches) and sea cucumbers are capable of absorbing oxygen through their intestines in addition to their gills when faced with hypoxic conditions. However, the possibility that this was so for mammals has never had conclusive results. Now, new research reveals that mammals, such as mice, rats or pigs, are able to breathe through their intestines , suggesting that delivering oxygen through the rectum could help save human lives. who suffer from respiratory problems. Information that can be very useful now that the COVID-19 pandemic continues to exert great pressure on global health and that has highlighted the shortage of ventilation devices with patients at risk of respiratory failure.
How did they find out?
Briefly depriving mice and pigs of oxygen and pumping oxygen into the bottoms of these animals.
“The rectum has a mesh of fine blood vessels just below the surface of its lining , which means that drugs given through the anus are easily absorbed into the bloodstream. This made us wonder if oxygen could also reach the bloodstream in the same way, “explains Ryo Okabe, leader of the work that publishes Med magazine.
In a group of 11 mice, they rubbed the intestines of four of them to thin the mucosal lining and improve oxygen uptake. Mice in a low oxygen environment died in an average of 11 minutes. However, when the researchers injected pressurized pure oxygen into the rectums of all the mice, the mice that had had the thin layer of mucus lining the intestine removed survived the one-hour experiment, with a survival rate of 75% and without producing obvious side effects.
While this finding indicates that mice can avoid respiratory failure by breathing through the butt, the need to remove the intestinal lining makes this technique unsuitable for humans.
An alternative method
They tested a different technique in mice and pigs, administering oxygenated fluid through the rectum. When placed in a non-lethal environment that contained only 10% oxygen, mice that received the fluid through the anus were able to walk considerably farther than those that did not, while the researchers also measured an increase in the amount. of oxygen that reached the heart of the animals. With pigs, the same technique increased their ability to walk in low-oxygen conditions.
“The level of arterial oxygenation provided by our ventilation system, if scaled for human application, is likely sufficient to treat patients with severe respiratory failure, which could provide life-saving oxygenation ,” the researchers conclude.
“Enteral ventilation through the anus”
The intention of this experiment was to search for a potential alternative to mechanical ventilation that brings air into the lungs of patients through the trachea. The lack of oxygen machines has made a team of scientists more creative when it comes to solving this shortage of ventilators, including the ECMO technique, extracorporeal membrane oxygenation, where blood is pumped out of the body and reoxygenated with a machine. , is even less available than ventilators, according to the Mayo Clinic.
Although it seems a bit unusual idea, the tissues of the rectum can absorb oxygen, which helps the animals to recover, according to the results of the experiment. The scientists behind the study propose that injecting oxygen into the rectum could one day help save human lives if conventional ventilation methods are not at hand.
Following the success of this animal model experiment, experts hope to begin a clinical trial of the treatment in humans sometime next year.
Referencia: Ryo Okabe et al, Mammalian enteral ventilation ameliorates respiratory failure, Med (2021). DOI: 10.1016/j.medj.2021.04.004
