It’s a gas! Travelling capsule and sensors a boon to gut research

A swallowable capsule with a built-in
gas sensor, microprocessor and wireless
transmitter. Image: RMIT

by Anne Crawford

The human gut and its microorganisms are attracting worldwide attention in scientific and clinical circles, and curiosity in the wider public. A Monash University PhD project that has helped develop techniques to measure intestinal gases as a byproduct of these microorganisms will give valuable insights into changes occurring with our gut bacteria in health and disease.



Central Clinical School (CCS) PhD student Ms CK Yao is part of a collaboration that has developed two novel techniques that can accurately measure and assess faecal gas species; capsules that travel through the gut and in vitro chambers with gas sensors.

Ms Yao and others in the Alfred Hospital and CCS’s Department of Gastroenterology collaborated with nanotechnician engineers from RMIT who raised and developed the idea of a gas-sensing capsule – a swallowable device that travels through the entire gut and samples the air within it, transmitting data to a wireless recorder outside the body. This was successfully trialled in pigs.

In another joint effort, Monash researchers worked with the engineers to develop gas sensors attached to ‘fermentation’ chambers in vitro which identify different types of gas produced by stool bacteria and how rapidly carbohydrates and proteins are metabolised within the large bowel.

“We can use these techniques to measure and understand how the metabolism of gut bacteria may differ in certain gut conditions – compared to health,” Ms Yao said.

The sensors measure gas species including carbon dioxide, hydrogen, methane and hydrogen sulphide.

“We were particularly interested in sulphide or rotten egg gas because there are no techniques that reliably measure it and because of its link with the development of ulcerative colitis,” Ms Yao said. Ulcerative colitis is a long-term disease in which the colon and rectum become inflamed resulting in bloody diarrhea, fever and abdominal symptoms.

“By using this array of gas sensors we can then measure the response of different types of food components or nutrients that will help us to formulate dietary strategies targeting the reduction of sulphide gas for several conditions, such as in ulcerative colitis or in individuals who complain of malodourous wind,” she said.

The technique allows in vitro faecal gas measurements that are real time, low cost, versatile, reliable and accurate.

Previously, gas production in the large bowel was measured in breath samples, a technique that wasn’t as sensitive and was variable.

Ms Yao said the study could potentially impact many areas of research.

“The availability of both these techniques will allow us to have access to the information about what’s going on and where, particularly in the large bowel, and the different types of gases that are getting produced throughout the entire gut. This information and could potentially be used in guiding the management for patients with gut conditions such as Irritable Bowel Syndrome,” she said.

Ms Yao, who works as a specialist gastrointestinal dietician, said she realised as a practitioner how much research is needed into understanding the effects of diet within the gastrointestinal tract, and that conducting the research for her PhD informs her practice. “I get a lot of questions from patients about gases and how this affects their symptoms,” she said. “We really need a lot of diet research in this area and there’s a big interest in this in our group.”

Professor Peter Gibson, head of the Department of Gastroenterology, Dr Jane Muir, Head of Translational Nutrition Science, and Dr Jaci Barrett, Senior Lecturer, are also involved in the research. The research is ongoing and will hopefully lead to translation into clinical trials.

Ms Yao’s PhD thesis, investigating the application of novel bio-sensing technology to better understand ulcerative colitis and irritable bowel syndrome, is six months off completion.

References:

Ou JZ, Yao CK, Rotbart A, Muir JG, Gibson PR, Kalantar-zadeh K. Human intestinal gas measurement systems: in vitro fermentation and gas capsules. Trends Biotechnol. 2015 Apr;33(4):208-13. doi: 10.1016/j.tibtech.2015.02.002. Epub 2015 Mar 12.

Ou JZ, Cottrell JJ, Ha N, Pillai N, Yao CK, Berean KJ, Ward SA, Grando D, Muir JG, Harrison CJ, Wijesiriwardana U, Dunshea FR, Gibson PR, Kalantar-Zadeh K. Potential of in vivo real-time gastric gas profiling: a pilot evaluation of heat-stress and modulating dietary cinnamon effect in an animal model. Sci Rep. 2016 Sep 16;6:33387. doi: 10.1038/srep33387.