A Friend, Not Foe: Common GI Tract Parasite Reduces Inflammation to Promote Gut Health Leave a comment

Blastocystis hominis parasite, 3D illustration.

The human gut is a thriving ecosystem, teaming with thousands of bacterial species whose interactions determine its health and susceptibility to diseases. While some microorganisms are harmful, many are beneficial and help keep the human body in good health. It is largely accepted that the more diverse the species of bacteria, the greater the capacity the gut has in regulating its health and combating diseases.

Higher levels of certain types of bacteria, or parasites, can result in an unhealthy gut, causing conditions like inflammatory disorders, irritable bowel syndrome, stomach cramps, bloating, diarrhea, and constipation.

However, in a new study conducted by researchers from the NUS Yong Loo Lin School of Medicine (NUS Medicine), a common microscopic parasite that inhabits the gastrointestinal tracts of humans, Blastocystis subtype (ST) 4, has been shown to be associated with benefits for the gut.

According to the Mayo Clinic, “Researchers don’t fully understand the role blastocystis play, if any, in causing disease. Some people experiencing diarrhea, abdominal pain or other gastrointestinal problems may have blastocystis organisms in their stool, but most commonly, blastocystis simply live in a person’s digestive tract without causing harm.”

The research, led by fellows Dr Deng Lei, Dr Png Chin Wen and Dr Lukasz Wojciech from the Department of Microbiology and Immunology at NUS Medicine, now shows that the blastocystis parasite actively suppresses gut inflammation and displays properties similar to probiotics that keep the gut healthy.

Published in the journal Cellular and Molecular Life Sciences, the series of experiments found that the parasite stabilized the bacteria ecosystem in the gut of laboratory models and promoted quicker recovery from inflammation.

“When one thinks of parasites, we do not normally associate them as beneficial organisms. However, the study proved that Blastocystis ST4 is not a pathogen, but could in fact promote better health of the gut.”

The ability of Blastocystis ST4in restructuring the state of the gut into a healthy composition of microorganisms could be a result of its ability to increase the types of bacteria that produce beneficial molecules, as well as increase immune cells that dampen inflammation.

The new findings suggest that detection of the parasite may in fact be linked to the presence of a healthy gut, and the microorganism could potentially be translated into probiotics to treat inflammation in patients.

Dr Png Chin Wen, another author of the study, added, “Our data indicates that Blastocystis ST4 behaves like an ‘ecosystem engineer’ that helps keep the bacterial environment of the gut diverse and versatile, to better combat potential diseases that may arise.”

“The common view of bacteria is that they are either good or bad. However, interactions between bacteria and the human body evolve over time, and the key is finding a balance that can cultivate a healthy environment for the gut,” said Dr Lukasz Wojciech, a co-author of the study.

While Blastocystis ST4 is shown to have beneficial properties, not all the subtypes of Blastocystis necessarily behave the same way, added the researchers. As found in an earlier study, a team from the school proved that another subtype could be harmful to the gut. Clinically, it is key for further studies to investigate the behavior of the microorganism’s various subtypes, for a more complete assessment of their respective implications.

Source: Lei Deng, Lukasz Wojciech, Chin Wen Png, Eileen Yiling Koh, Thet Tun Aung, Dorinda Yan Qin Kioh, Eric Chun Yong Chan, Benoit Malleret, Yongliang Zhang, Guangneng Peng, Nicholas Robert John Gascoigne, Kevin Shyong Wei Tan. Experimental colonization with Blastocystis ST4 is associated with protective immune responses and modulation of gut microbiome in a DSS-induced colitis mouse model. Cellular and Molecular Life Sciences, 2022; 79 (5) DOI: 10.1007/s00018-022-04271-9

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