Aussie breakthrough in gut pain treatment

When American researcher Ardem Patapoutian was jointly awarded the Nobel Prize in physiology in 2021, his work was hailed as a breakthrough in decoding the biology of the senses.

His life's toil had been aimed at identifying molecular receptors in skin and other organs that respond to mechanical forces, like those generated by touch and pressure.

Yet it was also hoped his findings would have significant medical applications, namely that they would unleash new paths in the quest to combat chronic pain.

For South Australian scientist Nick Spencer, Professor Patapoutian's lead has led to his discovery of the receptor Piezo2 in the colon and along with it, a major advance in treating debilitating gastrointestinal disorders such as irritable bowel syndrome (IBS).

While three in 10 Australians are affected by the long-term functional disorder, there is currently no medicine specifically designed to address IBS.

In some cases antispasmodics, antidiarrhoeals, antidepressants or antibiotics can be prescribed that have symptom-relieving side-effects but as some of these can also be harmful, therein partly lies the problem.

"Chronic pain from internal organs, such as the gut or bladder, is notoriously difficult to treat," Professor Spencer said.

"Opiates, including morphine and their derivates have been commonly used to treat a variety of types of pain but visceral pain doesn't respond well to the treatment and the drugs are highly addictive with a multitude of side effects."

By revealing the presence of Piezo2 in the gut, the Flinders University neurophysiologist and US research partner, Professor Hongzhen Hu, have potentially found a way to selectively silence pain sensations from internal organs without the need to frequently consume such medications.

"It was previously known that many different ion channels are located on the 'pain-sensing' neurons that communicate from the gut to the brain," Prof Spencer said.

"But our study ... has identified the major ion channel in the colon that responds to mechanical stimulation leading to the sensation of pain.

"Furthermore, we have discovered the major ion channel that responds to this mechanical pain is a member of the Piezo ion channel, specifically Piezo2."

He and Prof Hu will now focus on finding a treatment for visceral pain also common in conditions such as abdominal cancer and endometriosis, for which various steroids and painkillers can be prescribed but they typically also risk inviting potentially problematic side effects.