TCM researchers get to guts of matter in bowel treatment

Researchers at Baptist University's School of Chinese Medicine have identified a new way to treat irritable bowel syndrome - a common disorder that affects the stomach and intestines.

A research team led by director of the school's clinical division Bian Zhaoxiang, assistant professor Xavier Wong Hoi-leong and post-doctoral research fellow Zhai Lixiang screened thousands of food components and their breakdown products in the feces of 290 patients with IBS-D - the most common form of IBS.

They found that the organic compounds phenethylamine and tryptamine are more highly concentrated in the feces of patients with IBS-D, which suggests that the concentration of the two compounds is associated with the severity of diarrhea in IBS-D patients.

"IBS-D patients experience frequent episodes of diarrhea with accompanying abdominal pain, which reduce the quality of life. The research discoveries offer promising potential for the development of therapies for IBS-D based on the inhibition of the pathway," said Bian.

The team also found that Ruminococcus gnavus, a type of gut bacteria enriched in IBS-D fecal samples, is a primary producer of phenethylamine and tryptamine.

Mice that received R gnavus samples in their guts experienced symptoms of diarrhea, suggesting that the bacteria produces phenethylamine and tryptamine to trigger IBS-D in mammals.

Researchers also found that phenethylamine and tryptamine stimulates the production of serotonin - a neurotransmitter that thereby stimulates gut motility associated with IBS-D.

It was then discovered that shutting down the trace amine-associated receptor - a protein that activates various organic compounds - would inhibit serotonin production and effectively alleviate diarrheal symptoms in mice.

Researchers also found that a low-protein diet consisting of food items such as fresh fruits, vegetables and bread may help reduce the gut motility in IBS-D patients.

Researchers found that a low-protein diet, which tends to be lower in phenylalanine - a precursor of phenethylamine, suppressed gut motility in mice.

"Developing strategies to reduce the microbial transformation of dietary amino acids into phenethylamine and tryptamine, such as dietary intervention with reduced consumption of high-protein food items may represent a feasible approach for the management of IBS-D," Wong said.