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Breast-feeding associated with a healthy infant gut, new study shows
The study is published in the April 30, 2012 issue of BioMed Central’s open access journal Genome Biology,
and is an Editor’s Pick.
Study leader Robert Chapkin, of Texas A&M University, explained, “While we found that the microbiome of breast-fed infants is significantly enriched in genes associated with ‘virulence,’ including resistance to antibiotics and toxic compounds, we also found a correlation between bacterial pathogenicity and the expression of host genes associated with immune and defense mechanisms.”
A Research Highlight review of the study states that it is an “important first step towards better understanding the biological mechanisms underlying the parallel development of host and microbiome during early life. They demonstrate the power of new experimental and analytical approaches that enable the simultaneous analysis of the microbiome and the host response.”
Study Design, Bioinformatics
The human intestine is lined by epithelial cells that process nutrients and provide the first line of defense against food antigens and pathogens, observed the study authors. Approximately one-sixth of intestinal epithelial cells are shed every day into feces, providing a non-invasive picture of what is going on inside the gut.
In this study, the researchers used transcriptome analysis to compare the intestines of three- month-old exclusively breast-fed or formula-fed infants, and relate this to their gut microbes. Transcriptome analysis looks at the small percentage of the genetic code that is transcribed into RNA molecules and is a measure of what genes are actively making proteins. Concurrently the microbes (microbiome) were identified by genetic analysis.
Friedberg, part of the bioinformatic analysis team, said, “my role in the study was to design and run the computational genomic analyses needed to figure out which type of bacteria were living in which baby, and what these bacteria were capable of doing.
I also designed and ran a concurrent analysis to look at which genes were expressed in the baby gut in response to the different bacteria and/or diet.”
Breast milk, immune system, microbe population
The study shows that babies that had been fed only breast milk had a wider range of bacterial colonization than formula-fed babies; they also found a link between the bacteria present and changes in the infant’s expression of genes involved in the immune system.
“Our findings suggest that human milk promotes the beneficial crosstalk between the immune system and microbe population in the gut, and maintains intestinal stability,” Chapkin said.
The study, “A Metagenomic Study of Diet-Dependent Interaction Between Gut Microflora and Host in Infants Reveals Differences in Developmental and immune Responses” was authored by Scott Schwartz, Texas A&M University; Iddo Friedberg, assistant professor microbiology and computer science (affiliate), Miami University; Ivan Ivanov, Laurie Davidson, Jennifer Goldsby and David Dahl of Texas A&M University; Damir Herman, University of Arkansas; Mei Wang and Sharon Donovan, University of Illinois; and Robert Chapkin, Texas A&M University.
Material also contributed by BioMed Central