A French study reveals that primates with an appendix are less affected by infectious diarrhea than other species.
- The ileocecal appendix is a small cylindrical growth located in the large intestine.
- French researchers have discovered that primate species with an appendix are less affected by infectious diarrhea than others.
- In addition, the median age of onset of diarrhea – whether severe or not – was significantly higher in animals with an ileocecal appendix.
The ileocecal appendix, more commonly called appendix, is a small growth located in the large intestine. Its function within the organism remained, until present, still quite mysterious. A research team from Inserm, CNRS, the National Museum of Natural History, the University of Rennes, Sorbonne University and the Eugène Marquis center made an interesting discovery by studying primates also having this structure: it could have a protective effect against infectious diarrhea.
Appendix: its protective role against diarrhea highlighted
After noting in previous work that mammals with an appendix had a greater longevity than those without one, the team of French researchers wondered how the organ could affect the frequency and severity of diarrhea.
Scientists examined veterinary records of 1,251 primates of 45 different species (13 had an appendage like the gorilla, 32 did not not like gelada). Half of these animals suffered from at least one episode of diarrhea during the 20 years of monitoring, with 13% of attacks qualifying as “severe”.
“In primates with an appendix, the frequency of episodes of diarrhea was much lower (approximately – 85%) than in those who do not have any. Cases of severe diarrhea were also much less common, particularly during the first quarter of life when the risk is highest. (this risk then gradually decreases throughout life.)“specifies Inserm in a communicated published on October 30, 2023.
Monkeys with an appendix developed these digestive disorders later than the others. Furthermore, none of them was diagnosed with acute appendicitis during the 20 years of follow-up.
“These results support the hypothesis of the protective role of the ileocecal appendix against infectious diarrhea in primates”comments Jérémie Bardin, co-first author of the study. “The observation of a particularly important protective effect during the first part of life, the period most vulnerable to severe diarrhea, but also the most optimal in terms of reproductive capacities, argues in favor of a more selective role in the evolution”adds Éric Ogier-Denis, Inserm research director within the Oncogenesis, Stress and Signaling unit who led the study with Michel Laurin, CNRS research director at the Paleontology Research Center – Paris.
Ileocecal appendage: any thoughts on appendectomy?
Mortality linked to infectious diarrhea was identified as the second cause of mortality in human children between 1 month and 5 years old in 2015. So for researchers, their discovery – if it is confirmed and deepened by other work – could lead to a reflection on our own appendix.
“If the function of the appendix in humans is the same as in other primates, the protection afforded by the appendix against diarrhea more than compensates for the risk of developing fatal appendicitis”write the authors in their article published in the journal Scientific Reports end of September.