Listening to Your Gut Feelings

The human gastrointestinal tract is not particularly well understood by researchers or medical professionals. This is due, in large part, to the fact that it is challenging to access it for studies. This is particularly bad news for those with disorders of the gastrointestinal tract, like the seven million people with an inflammatory bowel disease such as Crohn’s disease or ulcerative colitis. These chronic conditions can significantly impact a person's quality of life, causing symptoms like abdominal pain, diarrhea, and weight loss. Understanding the intricacies of the gastrointestinal tract is essential for developing better treatments and improving the lives of those affected by these conditions.

Unlike other parts of the body, such as the skin or blood, the interior of the digestive system is hidden from view. Researchers must rely on a combination of imaging techniques, such as endoscopy and imaging scans, along with samples obtained through invasive procedures like biopsies, to gather information. These methods, while valuable, only provide snapshots of the gut's state and may not capture the dynamic changes that occur during digestion and disease progression.

Adding to the complexities of studying the gastrointestinal tract, many biomarkers crucial for understanding its functions and disease processes are short-lived. These biomarkers, which could provide valuable insights into the real-time activity of the gut, may not be detectable when samples are taken via traditional endoscopic procedures to be analyzed in a laboratory at a later time. The dynamic nature of the digestive system means that key molecules, hormones, and microbial metabolites can change rapidly, influenced by factors like food intake and gut microbiota fluctuations. This inherent volatility underscores the need for innovative techniques that allow for the real-time monitoring of the gastrointestinal environment, helping researchers capture the nuances of its intricate processes and the rapid changes that often occur.

A noninvasive technique that could help to reveal the secrets of the human gut has recently been developed by a team led by researchers at MIT. Their tiny smart pill, about the size of a blueberry, is safe to be ingested. Once it begins its transit of the gastrointestinal tract, it can detect key biomarkers in real-time, and immediately report its findings to clinicians wirelessly.

The pill contains specially engineered bacteria that can detect nitric oxide and hydrogen sulfide (although in principle, other molecules could be recognized). These biomarkers were selected because they are very short-lived, and are important in understanding the inflammation associated with a number of bowel diseases. When nitric oxide or hydrogen sulfide come into contact with the bacteria, they emit light.

That light is then detected by electronics within the pill. The findings are transmitted wirelessly to nearby devices, like smartphones or computers. Not only can the presence of certain molecules be determined, but also their quantities. This real-time information gives physicians an unprecedented view of the current state of the gut, which could allow them to initiate treatments when early warning signs of disease flare-ups are detected, possibly saving the patient from a stay at the hospital after the condition has already gotten out of control.

The new insights that this pill will give researchers into the inner workings of the gastrointestinal tract, in health and disease, may also lead to the development of new therapies in the future. To date, however, the smart pill has only been tested in pigs, so it may be some time yet before this device makes its way into the toolboxes of gastroenterologists and other researchers.