直腸呼吸の医学的確立
Hello everyone, SCIENSPOT is a podcast that shines a spotlight on the latest scientific
technology from Japan. Your host is REN from SCIEN-TALK. When you think of breathing, you
think of lungs. But what if there was another way to oxygenate your body?
Today, we're spotlighting revolutionary research from Japan that confirms the medical
concept straight out of science fiction, internal ventilation, or breathing through
the rectum. Japanese researchers have successfully completed the world's first human clinical
trial, proving the safety of this groundbreaking technique.
We are covering the findings published by a team led by Professor Takanori Takabe of
Tokyo Science University, Osaka University, and Associate Hospital Professor Fujii from
Nagoya University Hospital. Severe respiratory failure, such as acute
respiratory distress syndrome, ARDS, involves the loss of gas exchange function in the lungs
and has a very high mortality rate. Standard treatments include mechanical ventilators
and extra-corporeal membrane oxygenation. However, these are invasive. Ventilators
can further damage the lungs and ECMO carries risks and complications.
Worldwide, there is an urgent need for minimally invasive therapy that allows the lungs to
rest while still supplying the body with oxygen. The research team drew inspiration
from certain aquatic organisms that perform gut respiration. They developed the internal
ventilation method to supply oxygen through the large intestine. To move this innovative
concept toward patients, they first needed to rigorously confirm its safety in healthy
humans. The core of this technique relies on a liquid
oxygen carrier called Parfluorodecalin, or PFD. PFD is a fluorine-based liquid known
Enteral Ventilationの安全性
for its remarkable ability to dissolve very large amounts of oxygen. Crucially, it is
chemically stable and not absorbed by the body. Think of PFD as a molecular scuba tank.
When this liquid is administered via the rectum, it releases its dissolved oxygen into a vast
network of blood vessels in the large intestine wall. Because PFD itself is not absorbed into
the bloodstream, it avoids systemic toxicity and passes through the body's safety, acting
only as a localized oxygen delivery system. The study was a phase 1 dose escalation trial
involving 27 healthy adult males. They received an increasing dose of non-oxygenated PFD,
ranging from 25 ml up to 1,500 ml. The key safety findings are high safety,
zero absorption, and tolerability. Throughout the trial, no serious adverse events or
dose-limiting toxicities occurred. Blood tests for liver and kidney function showed
no significant changes. Their absorption means the most critical findings for safety.
PFD concentration in the blood samples remained below the detection limit,
confirming that PFD is not absorbed systematically. Minor side effects like abdominal discomfort were
reported in the higher dose group, but they were all mined, transient, and resolved naturally.
Although the trial focused on safety and used PFD without maximum oxygen loading,
the researchers observed a slight but important increase of about 1% in peripheral blood oxygen
saturation, and in groups receiving 100 ml or more. This suggested that the basic principle
works. Atmospheric oxygen dissolved in the PFD was likely derived to the body via concentration
difference with venous blood. The research team has successfully proven the safety and
tolerability of internal ventilation using PFD in humans. This critical safety evidence
Enteral Ventilationの効果
is a major milestone, moving this once theoretical concept closer to clinical application.
The next step is testing oxygen-loaded PFD in actual patient to verify its therapeutic
effectiveness, and if successful, this low-invasive method could supplement or replace current
technologies, potentially saving the lives of severely affected patients, including newborns.
That's all for today's SciencePod. I'd love for you to listen to the podcast and
post your thoughts with the hashtag SciencePod. Thank you for listening, and see you next time.
