Breast Milk and Microbiota in the Premature Gut: A Method of Preventing Necrotizing Enterocolitis.

Necrotizing enterocolitis (NEC) is a devastating inflammatory condition of the intestine, which affects premature infants and causes untold damage. Its pathogenesis has to do with how colonizing bacteria interact with the immature newborn intestine. An immature innate immune response with increased TLR-4 on the cell surface and increased signaling molecules, such as NF-κB, can cause excessive inflammation. This is in conjunction with a decrease in the appearance of regulatory molecules which effect the control of innate responses. This condition is so devastating that it must be prevented and not treated. Fortunately, breast milk and probiotics can affect the condition leading to reduced inflammation. How does this effect work? We have shown that breast milk tryptophan and Bifidobacterium infantis result in a metabolite (indole-3-lactic acid) response, which is anti-inflammatory via inhibition of the aryl hydrocarbon receptor transcription factor which stimulates an IL-8 response. We have also shown that breast milk complex carbohydrates interacting with Bacteroides fragilis can cause short-chain fatty acids which exert anti-inflammatory effects on the newborn intestine. These breast milk metabolites could help prevent NEC if shown to be effective clinically.