Monday, September 10, 2012
health of individuals can be influenced by the diversity of microbes colonising
the gut, and microbial colonisation can be especially important in regulating
both intestinal and immune development in infants. However, little is known
about the potential interactions between the host’s health at a molecular level,
their gut microbes, and diet.
The human intestine is lined by epithelial cells that process nutrients and
provide the first line of defence against food antigens and pathogens.
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 authors 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.
The results showed that the breast-fed babies had a wider range of microbes in
their gut than the formula-fed infants, but that their immune systems had
developed to cope.
Robert Chapkin from the Texas A&M University, who led this multi-centre study,
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 defence mechanisms.”
He continued: “Our findings suggest that human milk promotes the beneficial
crosstalk between the immune system and microbe population in the gut, and
maintains intestinal stability.”
Scott Schwartz, Iddo Friedberg, Ivan V Ivanov, Laurie A Davidson, Jennifer S
Goldsby, David B Dahl, Damir Herman, Mei Wang, Sharon M Donovan and Robert
Chapkin. A Metagenomic Study of Diet-Dependent Interaction Between Gut
Microbiota and Host in Infants Reveals Differences in Immune Response. Genome
Biology, (in press/April 2012)