Rodents and pigs share their ability to use their intestines for respiration with some aquatic organisms, according to a study published in the May 14 issue of the journal With. The researchers demonstrated that the delivery of oxygen gas or oxidized fluid through the rectum provided important recovery for two mammalian specimens of respiratory failure.
“Artificial respiration support plays an important role in the clinical management of respiratory disease caused by acute illnesses such as pneumonia or acute bronchitis,” said Tagonori Dekbe (ake Dekeleb), senior research author at the University of Tokyo Medical and Dental and Cincinnati Children’s Hospital Medical Center. “While side effects and safety need to be fully assessed in humans, our approach may set a new precedent for supporting patients with respiratory distress.”
Many aquatic organisms have developed unique intestinal respiratory mechanisms to live in low oxygen levels using organs other than the lungs or gills. For example, sea cucumbers, freshwater fish called lochs and some freshwater catfish use their intestines for respiration. But whether mammals have similar abilities is highly debated.
In the new study, Takeby and his collaborators provide evidence for intestinal respiration in mice, rats and pigs. First, they designed an intestinal gas ventilation system to administer pure oxygen through the rectum of rats. They showed that without the system, no rats escaped the 11-minute very low oxygen level. Through intestinal gas ventilation, more oxygen reached the heart, and 75% of rats escaped from normally low oxygen levels within 50 minutes.
This is unlikely to be clinically possible because the intestinal mucosa requires abrasion of the intestinal mucosa, especially in critically ill patients – so researchers have also developed a liquid-based alternative using oxidized perfluorochemicals. These chemicals have already been clinically proven to be biocompatible and safe for humans.
The intestinal fluid ventilation system provided therapeutic benefits for rodents and pigs exposed to non-lethal low oxygen conditions. Mice that receive intestinal ventilation may walk as far as 10% of the oxygen chamber, and that more oxygen reaches their heart compared to mice that do not have ventilation. Similar results were evident in pigs. Intestinal fluid ventilation increased their oxygen levels, altering skin pain and cooling, without creating obvious side effects. Taken together, this strategy has been shown to be effective in delivering oxygen, which tends to relieve symptoms of respiratory failure in the sample systems of the two mammals.
With the support of the Japan Agency for Medical Research and Development to fight the corona virus disease 2019 (COVID-19) Epidemiologist, researchers plan to expand their preliminary studies and pursue regulatory measures to accelerate the path to clinical translation.
“Recent SARS – Cove-2 The epidemic is increasing the medical need for ventilators and artificial lungs, resulting in a shortage of available equipment and endangering the lives of patients worldwide, ”says Tagbe. “The amount of arterial antioxidants supplied by our ventilation system, if measured for human use, would be sufficient to treat patients with severe respiratory distress, providing life-saving antioxidants.”
Note: Rio Okabe, Toyobumi F. Sen-Yoshikawa, Yosuk Yoniyama, Yuhei Yokoyama, Satona Tanaka, Akihiko Yoshiwa, Wendy L. Thompson, Gokul Goyanbe, 14 May 2021, With.
DOI: 10.1016 / j.medj.2021.04.004
This work was supported by a research project on emerging and re-emerging infectious diseases, research projects on COVID-19, from the Japan Agency for Clinical Research and Development, and the AMED Translation Research Project and the AMED Project for Technological Innovation in Regenerative Medicine.