Investors Lab

Beyond butt breathing: A breath of fresh air

A picture of a man sitting on the edge of a hospital bed in front of a row of mannequins that have their rears exposed

Physician Takanori Takebe has shown it’s possible for mammals to get oxygen through their anuses. But whether it’s possible and practical for human patients who have trouble breathing is an open question.

Courtesy of Cincinnati Children’s Hospital Medical Center

By Elana Spivack

Several years ago, Takanori Takebe’s father caught pneumonia and had to be put on a ventilator. A medical doctor and stem cell biologist at Cincinnati Children’s Hospital Medical Center in Ohio and the University of Osaka in Japan, Takebe was shocked by how invasive ventilators are, and began to wonder if there were other ways to help oxygenate patients. Now, he and his colleagues are testing an experimental enemalike treatment that delivers an oxygen-rich liquid through the rectum into the bloodstream, Maria Temming reports for SN.

🩸 A new way to breathe

Takebe drew inspiration from nature as well as his background in gastroenterology. Various animals get their oxygen through their skin, genitals or guts. For example, freshwater fish called loaches swallow air to consume supplementary oxygen in addition to what their gills take in. The human intestinal tract, he knew, is replete with blood vessels, so perhaps the intestines could be a good candidate for blood oxygenation.

Enemas already deliver medicine into the bloodstream this way. The treatment Takebe and his team developed sends into the rectum a liquid called perfluorodecalin, which is already incorporated in some medical procedures and can be loaded with oxygen. Once in the intestine, perfluorodecalin releases its oxygen into the body while its chemical structure opens to absorb the byproduct carbon dioxide.

This research received the Ig Nobel Prize — a satirical award that honors humorous yet thought-provoking scientific research — in 2024. Most recently, the team published the results of their first human trial, testing nonoxygenated perfluorodecalin on 27 healthy male volunteers in Japan to gauge this method’s safety. Takebe funded this research through EVA Therapeutics, a startup he cofounded for this research.

🫁 Beyond mechanical ventilators

This technique is still a long way from potentially helping people with impaired breathing respire through their anus, though future clinical trials will test whether oxygenated perfluorodecalin actually delivers oxygen to human bloodstreams through the rectum. Meanwhile, the mechanical ventilator market’s estimated value was about $3.17 billion in 2024. These ventilators come with risks, increasing the possibility of developing infections like pneumonia, blood clots, fluid buildup and lung damage. Failing this, doctors can pump a patient’s entire blood volume through an artificial lung to oxygenate it in a process similar to dialysis. Between these two methods, there’s an entire market available for alternate methods of assisted breathing.

🌬 A breath of fresh air

Some firms are already trying to break open this market to offer alternatives to mechanical ventilators for assisted breathing:

  • Inspira Technologies: Founded in 2018, this Israel-based company (NASDAQ: IINN) is developing technologies that enrich blood with oxygen, remove carbon dioxide and continuously monitor blood-oxygen levels, all while a patient remains awake. In December 2025 the company raised $1.8 million, bringing their total funding to $10.5 million.
  • VQ Biomedical: This startup is developing a device that provides supplemental oxygen directly to the bloodstream of patients with respiratory failure. Called an intravascular oxygenation catheter, this technology directly oxygenates the blood so a patient’s injured lungs can heal. Founded in 2023, this North Carolina–based company has raised a total of $4.1 million, most recently garnering $1.7 million in its March 2025 seed round from lead investors like Duke Capital Partners and Harbright Ventures.
  • XN Health: This medical device company out of Houston, Texas offers a product called a diaphragm stimulator, supporting the muscle under the lungs in patients who need a mechanical ventilator. By inducing diaphragmatic contractions, this stimulator may help prevent a condition called ventilator-induced diaphragm dysfunction, for which this company gets an honorable mention. Founded in 2021, this startup received a $15,000 grant from Texas A&M Innovation in May 2022 and an undisclosed amount of seed funding in December 2023 from investors like the Mayo Clinic.

It just goes to show that looking to the future sometimes requires a look behind.

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