Saturday, May 22, 2021

"Some mammals can breathe through their butt, scientists discover"


Appropriately enough this version of the story is from Inverse:

This finding could lead to an alternative treatment for severe Covid-19.

A long time ago, ancient fish swam in a harsh aquatic environment, with scarce light and limited oxygen. Many died but some survived and evolved, eventually giving rise to Misgurnus anguillicaudatus — a type of loach fish common in parts of East Asia. The loach fish’s secret survival mechanism? A unique form of intestinal breathing via their posterior.

In other words: loach fish breathe through their butt. But scientists now report this evolutionary breathing mechanism may not be limited to fish. 

Turns out certain mammals can also breathe through their intestines using a process researchers describe as “enteral ventilation via anus.” The breathtaking finding is described in a new paper published on Friday in the journal CellPress.

There’s also a timely reason for researchers to explore this technology: Covid-19. The study team argues the method explored here could eventually be used to help humans experiencing lung failure. This intestinal breathing technique, facilitated by external ventilation, could aid patients failed by or without access to current tools like ventilators.

What’s new — For the first time, researchers have proof that intestinal breathing can occur in mammals — albeit, with a little intervention.

When the research team injected either gaseous or liquid oxygen into the rectums of both rodents and pigs, a procedure known as enteral ventilation via anus (EVA), they found the animals were capable of intestinal breathing.

In fact, the procedure boosted oxygen levels in animals experiencing oxygen deprivation, increasing their chances of survival.

“A proof-of-principle EVA approach is effective in providing [oxygen] and alleviating respiratory failure symptoms in two mammalian model systems,” the team writes.

The animals experienced no apparent side effects from the somewhat unorthodox treatment.

A figure from the study summarizing the researcher’s intestinal breathing
experiment and illustrating how it could work in humans.Takebe et al

The controversy — The fact that land-based mammals and aquatic species share the capacity for this breathing is a remarkable finding for evolutionary biology. But it’s a pretty controversial idea within the medical research community, according to the scientists....