Many years ago, I found myself in a hospital emergency room, having a lively discussion (OK, maybe it was more of an argument) with a surgeon about whether the imminent removal of my swollen and inflamed appendix was going to be good or bad for my long-term health.
I knew I had to have the surgery, but I thought the surgeon’s attitude about my appendix, that peculiar worm-like pouch attached to the large intestine, was way too cavalier, and told him so.
“But nobody needs their appendix,” he said. “It doesn’t serve any purpose.” I could have pointed out to him that the medical community once believed that the thymus and pineal glands (among others) were vestigial structures, but I wasn’t well-versed in that tidbit of medical history yet and, anyway, I was in too much discomfort to prolong the conversation.
“Maybe you’re right,” I said, “but maybe you’re wrong. One day, scientists may figure out that the appendix does us some good after all.”
A nature reserve?
Is that day here? Perhaps, as biologist and science writer Rob Dunn (“The Wild Life of Our Bodies”) points out in a guest blog this week for Scientific American. He describes some new research that seems to support an intriguing (and definitely non-vestigial) hypothesis about the appendix that’s been gaining steam in recent years. It’s an idea that was first proposed by William Parker, an iconoclastic researcher and associate professor of surgery at Duke University School of Medicine.
“Parker thinks the appendix serves as a nature reserve for beneficial bacteria in our guts,” writes Dunn. “When we get a severe gut infection such as cholera (which happened often during much of our history and happens often in many regions even today), the beneficial bacteria in our gut are depleted. The appendix allows them to be restored. In essence, Parker sees the appendix as a sanctuary for our tiny mutualist friends, a place where there is always room at the inn.”
If Parker is right, Dunn adds, then “individuals with their appendix should be more likely to recover from severe gut infections that those without.”
Support for the concept
And that’s just what a new study, published in the December issue of the journal Clinical Gastroenterology and Hepatology, has found, as Dunn explains:
[A team of researchers] studied a pathogen, clostridium difficile, common even in places with good medical systems. … “C diff,” as it is known among the hip medical in crowd, is a deadly pathogen often encountered in hospitals, particularly when patients must be treated by prolonged courses of antibiotics.
C. diff does not appear to compete well with the native biota of patients’ guts, but when the native biota is depleted (as is the case after several courses of antibiotics) C. diff can grow quickly and take over. It is the hare to the good bacteria’s tortoise, a weed in the plowed field. C. diff is most dangerous when, after treatment, it recurs, which is to say when the native fauna of the gut and immune system cannot, together, prevent it from reinvading. If Parker’s idea is right, individuals without an appendix should be more likely to have a recurrence of C. diff than those individuals with an appendix.
To see if this is true, a team of researchers examined the records of 254 Winthrop University-Hospital (Long Island, NY) patients who had been infected with C. diff. They compared the recurrence rate among people with and without their appendix. “Two things became clear,” writes Dunn:
First, patients older than sixty were more likely to have recurrences of C. diff, independent of any other factors. Maybe gut bacterial communities age too and make older guts easier to colonize. Maybe something else. And then, second, the big result. … Individuals without an appendix were four times more likely to have a recurrence of Closteridium difficile, exactly as Parker’s hypothesis predicted. Recurrence in individuals with their appendix intact occurred in 11% of cases. Recurrence in individuals without their appendix occurred in 48% of cases.
A symbol of what we don’t know
As Dunn points out, these results don’t necessary mean that Parker is right. As is almost always true in science, but particularly here, “more research is needed.” After all, other factors, ones not yet identified, may explain the differences in the re-infection rates. But if Parker is right, then, well, we may not want to be so dismissive about our appendixes. Writes Dunn:
If you do not have your appendix anymore, you may be at an increased risk of recurrence and even death when confronted with a pathogen like C. diff, cholera or any of a wild kingdom of other pathogens. This possibility raises the question of what to do if your appendix (or your child’s appendix) becomes inflamed. For now, the answer is, at best, unclear. While appendicitis can be deadly, recent studies suggest some cases of appendicitis can be resolved using antibiotics, though the topic is an active area of research and little is known about the prognosis for individuals treated for appendicitis later life.
Might there, some day, be solutions other than surgery and antibiotics, solutions that aim at restoring the sanctuary of the appendix? Maybe. Until then, doctors keep cutting infected appendixes out. When they do, when they hold them up, they hold up a symbol — a somewhat gross, pinky-finger-sized symbol — both of our complex relationship with other species and of how little we know.
You can read Dunn’s post at the Scientific American Blog Network.