Chelsea Leu Science Date of Publication: 09.30.15.
09.30.15
Gut microbiota are everywhere nowadays, both because we’re all walking around in giant clouds of them, and also because scientific study of them is booming. These bugs are scarily deterministic: linked to weight, or mood, or what snack you’re craving. But those connections aren’t too surprising—gut bacteria live in your gut, after all. Now, though, scientists have pinned down four types of bacteria whose presence definitively prevents asthma—a chronic lung disease that would seem to have no business communicating with your nether regions.
But the two systems seem to be linked in a deep, developmental way. “What we’re learning is that the body is gut-centric in the way it sets up the immune system,” says Brett Finlay, a microbiologist at the University of British Columbia and an author of a Science paper on the results, published today. “We know there’s communication between the gut and different sites,” he says, whether it’s skin, eyes, or lungs.
Hence the connection with asthma, which is linked to hyperactive immune systems. Asthma is a big first-world problem, and it’s getting bigger—rates in developed countries have tripled or even quadrupled in the past 30 years, says Stuart Turvey, a University of British Columbia pediatrician and another author. Most doctors suspect it’s because we’re overusing antibiotics, throwing it at any bacterial problem that comes up and making our environments unhealthily clean. But they haven’t quite nailed down a mechanism that explains how antibiotics could cause asthma.
Mostly, that’s because scientists still don’t know anything about what lives in our sludgy interiors. “We are starting to discover this massive universe of bacteria,” Turvey says. And that includes the four bacteria they’ve found: Faecalibacterium, Lachnospira, Veillonella, and Rothia. Scientists found that levels of these bacteria, which they’ve dubbed FLVR (pronounced “flavor”), were unusually low in the stool of Canadian children who were at risk for developing debilitating, problematic asthma later in life. And when they introduced these bugs into young mice and then induced asthma, the mice didn’t develop inflamed airways—pretty convincing proof that these bacteria were protecting against asthma.
For the bacteria to prevent asthma, timing is key. The kids who had lower levels of FLVR when they were three months old somehow gained normal levels of them by the time they turned one, making their gut microbiota virtually indistinguishable from their non-wheezy peers. The difference, Turvey says, seems to be that those bacteria weren’t present when they were needed, during development. “Having the right bacteria in place at the right time is really important,” he says, “especially in those early months of life.”
The team is just beginning to figure out how exactly bacteria in your bowels affect what’s going on in your lungs. Right now, they think the chemical byproducts FLVR produce help train the immune system to do battle against harmful germs in those tender but crucial first days. “Without that training, the immune system becomes confused and causes inflammation in the lungs—that’s asthma,” Turvey says. Beyond that, though, they don’t know much.
Still, now that scientists can put a name (a cheesy acronym, even) to the bugs that help prevent asthma, they’re looking to develop better ways to diagnose kids earlier—theoretically, parents could just check to see how much FLVR their wee ones have in their poop. Further down the line, Turvey says, scientists could even use FLVR to come up with a preventative treatment for asthma. “That would be huge,” he says.
Traditionally, pediatricians have been taught to take a sort of seek-and-destroy tactic with bacteria. Considering these new findings, that could turn out to be a terrible strategy, since the bugs seem to be important for our very basic development. At the very least, it’s probably not a good idea to take antibiotics willy-nilly because they can kill all our microbes, good or bad, in one fell swoop (something NYU doctor Martin Blaser, in a conversation with WIRED, referred to as “nuking the village.”) “We need to revisit our relationship with bacteria,” Turvey says. “Our species have coevolved with them, and they’re really important for our health.”
Thankfully, the tide of medical opinion is shifting to take a more nuanced view on microbes—a White House-appointed Presidential Advisory Council on Combating Antibiotic-Resistant Bacteria (headed by Blaser) had its first meeting yesterday. That’s good news for the tiny organisms living inside us, just trying to make sure we develop the right way. Some of them, at least.
http://www.wired.com/2015/09/gut-microbiome-put-higher-risk-asthma/
— Last Edited by Greentea at 2015-10-05 08:14:50 —
