Appendix may be safe haven for "good" bacteria

NEW YORK (Reuters Health) - Contrary to conventional wisdom, the appendix may not be useless after all. New research suggests that the structure helps beneficial bacteria survive and repopulate the colon after these organisms become depleted as a result of an infection or drug treatment.

Beneficial bacterial, also referred to as commensal bacteria, help maintain a proper balance in the intestine and may also kill dangerous microbes. For example, this is why patients frequently develop gastrointestinal problems during or after a course of antibiotics. Along with the pathogen causing the infection, the antibiotic may destroy commensal bacteria as well.

This report “proposes a novel and unique function for the human appendix, for which the appendix is well suited,” senior author Dr. William Parker, from Duke University Medical Center in Durham, North Carolina, told Reuters Health. “Importantly, the proposal explains clearly why the function is not evident in our industrialized culture.”

The researchers’ hypothesis appears in the online issue of the Journal of Theoretical Biology.

A series of experiments and observations, led Parker’s team to theorize that the appendix serves as a protected reservoir for commensal bacteria. After a bout of diarrhea that evacuates the microbial contents of the colon, the bacteria in the appendix can emerge to repopulate the intestine.

In industrialized societies with good sanitation, this function may not be important, he and his colleagues suggest.

Whether or not the appendix actually has this apparent beneficial effect should not change how appendicitis is treated, Parker said.

For patients and physicians alike, the message is that symptoms of appendicitis always need to be evaluated, he emphasized.

“Although the function of the organ may have been determined, it is most certainly not important in our culture, and if you try to hang on to it after it gets inflamed, it could be deadly.”

SOURCE: Journal of Theoretical Biology, October 8, 2007 online issue.