Peer-reviewed: This work was reviewed and scrutinised by relevant independent experts.
Experimental study: At least one thing in the experiment was changed to see if it had an impact on the subjects (often people or animals) – eg: changing the amount of time mice spend on an exercise wheel to find out what impact it has on weight loss.
Animals: This is a study based on research on whole animals.
A Monash University collaboration has found that eosinophils, a type of white blood cell commonly associated with asthma and allergy, play an important role in maintaining a healthy gut.
Journal/conference: Immunity
Link to research (DOI): 10.1016/j.immuni.2022.05.014
Organisation/s: Monash University
Funder: A.I. was supported by a Fellowship from São Paulo Research Foundation ( 2016/15882-7 ) and an Eyes High Postdoctoral Fellowship from the University of Calgary . This work was supported by grants from the Swiss National Science Foundation ( SNSF310030_134902 to K.D.M., SNSF310030_156517 to N.L.H., and 31003A-156266 to T.V.P.) and the European Research Council (ERC, FP/2007-2013 ) Agreement no. 281785 to K.D.M. K.D.M. is also supported by a Canadian Institutes of Health Research (CIHR) grant ( PJT-165930 ). N.L.H. is supported by a National Health and Medical Research Council (NHMRC) of Australia SRF-B fellowship. A.D. was supported by an NSERC Discovery Grant ( DGECR-2019-00112 ). The IMC is supported by the Cumming School of Medicine, University of Calgary , Western Economic Diversification (WED), and Alberta Economic Development and Trade (AEDT), Canada.
Media release
From: Monash University
A Monash University collaboration has found that eosinophils, a type of white blood cell commonly associated with asthma and allergy, play an important role in maintaining a healthy gut.
Professor Nicola Harris, from Monash’s Central Clinical School, made the surprising discovery working with study co-lead, Professor Kathy McCoy from the University of Calgary, and scientists from Switzerland. Their paper was published in Immunity this week.
“The study showed a critical role for eosinophils in facilitating mutualistic interactions between host and microbiota, the millions of bacteria in the gut,” Professor Harris said. “It turns our views of eosinophil function on its head and will no doubt spur a lot more research into these relatively rare cells,” she said.
Eosinophils make up about 1-2 per cent of circulating white blood cells in healthy people in developed countries but are present in increased numbers in people who are severely allergic. “They play a tissue-destructive, pathological role in these allergies, they’re the bad guys,” Professor Harris said.
Around 10-15 years ago scientists realised that eosinophils accounted for 10 - 30 per cent of white blood cells in the gastrointestinal tract and asked why. The answer has remained a mystery, Professor Harris said. “We set out to answer why these supposedly tissue-destructive cells were sitting in the gut.”
The scientists investigated the possible role of eosinophils in the main functions of the small intestine using germ-free animal models and advanced 3-D microscopy. They found that eosinophils co-ordinated the gut’s response to bacteria.
“They were limiting overt inflammation and by doing that they were limiting tissue damage,” Professor Harris said. “The most important factor of this damage is the length of the villi, the finger-like projections that come up from the wall of the intestine, which absorb nutrients.
“We found eosinophils kept those villi intact and without them the villi became much shorter and lipid uptake was reduced.
“So, they were helping to maintain this absorptive area that allowed extraction of nutrients from the diet at a proper level.”
The study also found that gut motility was dysregulated in the absence of eosinophils and that they could impact the structure of tissue.
“These cells are a lot more complicated than previously believed – we need to think about them in an entirely different way,” Professor Harris said. “They’re doing a lot that’s completely unexplored.”
Professor Harris said the findings had many implications for those studying the cells in both the clinical and basic research spheres.
Co-first authors on the paper were Dr Aline Ignacio from the University of Calgary and Dr Kathleen Shah from the Global Health Institute, Swiss Federal Institute of Technology, Lausanne, Switzerland.