14 DAY TRIAL // For long, the appendix has been regarded as a trouble causing evolutionary ballast. But a new research suggests that the appendix could have in fact an active beneficial role, being a "safe house" for the good gut bacteria.
Based on observations and experiments, the team at the Duke University Medical Center said that the beneficial bacteria located in the appendix can determine a gut to repopulate with its flora, following a bout of diarrhea that cleanses it completely. "While there is no smoking gun, the abundance of circumstantial evidence makes a strong case for the role of the appendix as a place where the good bacteria can live safe and undisturbed until they are needed," said lead researcher Dr. William Parker, assistant professor of experimental surgery.
The appendix is a thin 2-4 in (5-10 cm) long pouch situated at the joint of the large and small intestines. Its function has been a puzzle for the researchers for long, and the only sure thing is that it contains an immune system.
Some microbes from the gut digest food that the human digestive juices cannot, providing some useful nutrients for the body (like vitamin K). The Duke team points that the immune system cells encountered in the appendix have a role of defending, rather than killing the beneficial bacteria.
For ten years, Parker has been investigating the dynamics of the gut bacteria in biofilms, thin layers located atop the intestines consisting of a mix of microbes, mucous and immune system molecules.
"Our studies have indicated that the immune system protects and nourishes the colonies of microbes living in the biofilm. By protecting these good microbes, the harmful microbes have no place to locate. We have also shown that biofilms are most pronounced in the appendix and their prevalence decreases moving away from it." said Parker.
"This new function of the appendix might be envisioned if conditions in the absence of modern health care and sanitation are considered. Diseases causing severe diarrhea are endemic in countries without modern health and sanitation practices, which often results in the entire contents of the bowels, including the biofilms, being flushed from the body," he explained.
"The appendix's location and position is such that it is expected to be relatively difficult for anything to enter it as the contents of the bowels are emptied. Once the bowel contents have left the body, the good bacteria hidden away in the appendix can emerge and repopulate the lining of the intestine before more harmful bacteria can take up residence. In industrialized societies with modern medical care and sanitation practices, the maintenance of a reserve of beneficial bacteria may not be necessary. This is consistent with the observation that removing the appendix in modern societies has no discernable negative effects." continued Parker.
For several decades, the "hygiene hypothesis" has been the explanation for the high incidence of appendicitis in developed countries. The obsession for "hygiene" in these countries could boost allergy and even autoimmune disease because people's immune systems are not challenged on a daily base by the array of parasites or germs common in the environment and when the immune systems are triggered, they often overreact.
"This overreactive immune system may lead to the inflammation associated with appendicitis and could lead to the obstruction of the intestines that causes acute appendicitis. Thus, our modern health care and sanitation practices may account not only for the lack of a need for an appendix in our society, but also for much of the problems caused by the appendix in our society." said Parker.