Frogs could help us fight food allergies. The study of bitterness sensors in amphibians could play a role in understanding the mechanisms behind food allergies and thus help develop a treatment to completely cure them, according to a study carried out by researchers at Northeastern University (United States) and published in the journal Plos Genetics.
Frogs, like humans, have different taste receptors. They can thus sense salty, sweet, sour, bitter or even umami. Different sensors therefore allow them to identify whether a food is nutritious or whether it could contain toxins and therefore be dangerous to them. In this study, it was the bitterness receptors that interested the American researchers. "Frogs have up to ten times more bitterness sensors than humans", explains to Science and Future Jing-Ke Weng, co-author of the study.
Indeed, some amphibian species have up to about 250 bitterness sensors, called TAS2Rs, distributed throughout their body, from the tongue to the skin and certain organs such as the liver. This is particularly the case of the wood frog (Lithobates sylvaticus) having 248 TAS2Rs, compared to only 25 in humans, mainly in the mouth, but also present, in smaller quantities, in the intestine, the liver and even the brain.
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TAS2Rs signal the body about dangerous foods
Amphibians are therefore a very large resource for studying the action and role of TAS2Rs. They have evolved in environments that have forced them to develop a large number of bitterness sensors in order to avoid feeding on insects or plants that are potentially dangerous for them. Humans have evolved in the same way, " This is also why we have the reflex to smell our food if it seems suspicious, in order to identify a potential danger", explains Professor Jing-Ke Weng.
Thus, the TAS2Rs, once in contact with a dangerous food, serve to signal it to the rest of the body, triggering a behavioral response and a response from the immune system which will then do everything to evacuate the toxins, " particularly through vomiting or diarrhea”, the researcher explains. In order to better understand this mechanism, he explains that, in the case of a food allergy, "The molecules contained in the food to which we are allergic are not absorbed by the body when they are in the stomach and therefore arrive in the intestine, where the allergic process begins."
Food allergy, an abnormal reaction of the immune system
A food allergy is an abnormal reaction of the immune system, appearing after the ingestion of a particular food. Food allergy can result in itching, localized or even generalized hives, or even abdominal pain, vomiting or diarrhea. According to theWHO, approximately 220 million people suffer from food allergies worldwide.
However, these bitterness sensors could have another role. Indeed, they could affect the onset of a food allergy. However, according to the researcher, " "We do not yet fully understand the role that TAS2Rs play in the development of an allergy."To better understand the mechanisms behind food allergies, and why not, to be able to cure them one day, scientists are therefore looking at the TAS2Rs of amphibians, which have a very large reserve.
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Future treatments to cure allergies
The study of these bitterness receptors could therefore " lead us to understand their role in the appearance of a food allergy", says Jing-Ke Weng, and allow better identification of the exact molecules that the body rejects, according to the different allergies. This precise knowledge is crucial in creating a truly effective treatment against food allergies. The researcher also suggests that other studies and research are underway to develop vaccines and therapies allowing a complete cure for a food allergy. Indeed, today, "Existing therapies can desensitize the body to the food, but not cure the allergy; as soon as the treatment is stopped, the allergy returns sooner or later.", he explains.
However, many more studies and researches remain to be done in order to develop a fully effective treatment against food allergies. This is why the in-depth study of these bitterness receptors, TAS2Rs, is necessary, in order to have a better overview of the substances rejected by the body of patients, and to be able to create a treatment adapted to each allergenic molecule and each type of food allergy.
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