(Antibiotics, Asthma, and an Idea)
Approximately 250,000 people die prematurely each year from asthma. Over the past century, asthma prevalence has continued to rise in developed countries. And prevalence is predicted to continue rising. According to the American Academy of Allergy, Asthma, and Immunology, the number of people living with asthma will likely reach 100 million by 2025. Recent studies have linked antibiotic use with allergic airway disease.* For Brett Finlay (University of British Columbia) the lightbulb moment occurred when his wife, a pediatrician, mentioned that children exposed to antibiotics as infants were more likely to develop asthma. Antibiotic treatment can result in massive changes in the gut microbiota community. Could our gut microbes impact asthma?
The Finlay Lab decided to conduct experiments examining the potential role of the gut microbiota on asthma susceptibility. The research, spearheaded by Shannon Russell, a UBC grad student, utilized an asthma mouse model. Russell found that mice treated with vancomycin, a commercial antibiotic, exhibited a decrease in gut microbes and increase in asthma severity. Changes in microbial composition were most pronounced in perinatal exposure (meaning the mama mice received antibiotics and the antibiotic exposure continued after birth). In contrast, the impact of vancomycin on the gut microbiota of adult mice was less severe. Furthermore, infant mice (but not adult mice!) exposed to vancomycin were significantly more susceptible to asthma.
According to the Finlay Lab, gut microbes have the greatest influence on immune development during a “critical window” from birth to three weeks of age in mice. Antibiotic treatment during this time frame impacts the development of the immune system and may contribute to the development of allergic diseases, including asthma.
The next step involves the development of better antibiotic and/or microbial therapies to treat bacterial infections without promoting asthma development. The gut-lung axis was (and is) a relatively new and unexplored field. I am excited to learn what my fellow lab mates discover next!
Sources + Additional Information:
* For a nice review, check out Noverr and Huffnagle’s “The ‘microflora hypothesis’ of allergic diseases” published in Clinical and Experimental Allergy: http://www.ncbi.nlm.nih.gov/pubmed/16393316