Probiotics: Clinical applications of probiotics and basic background

It was standing room only at a presentation on probiotics given at this year's PAS conference.

The role of commensal bacteria in the intestine in relation to intestinal development,the multi function of the intestine and a healthy gut immune function were addressedby the presenters, including Josef Neu, University of Florida, Gainesville, Florida,Philip M. Sherman, Hospital for Sick Children, University of Toronto, Toronto,Canada, and W Allan Walker,Harvard University Mucosal Immunology Laboratory, Boston,MA.

Dr Neu discussed the role of intestinal microbiome, defined as the full collectionof microbes in humans. He noted that there were over 600 species of microbes inthe gastrointestinal tract and the colon houses the largest number.

Although we often equate bacteria with “bad”, most GI microbes aregood and they assist in nutrient metabolism, Vitamin K, tissue development, andresist colonization of the bad bacteria. When many microbes are present thereis a proliferation of capillaries.

When a baby is born, there are no microbes in the GI tract and the ones that settlein first most likely will form the core of the microbes. Babies that are bornpremature, and via caesarean section may not develop the core microbes properlyand thus may run the risk of long term consequences. Premature babies are givena lot of antibiotics, and C-section babies do not get the chance to come intocontact with the maternal vaginal microbiota.

In discussing intestinal microbial mucosa interactions and intestinal diseases,Dr Sherman noted that fetal intestinal environment is effected by colonization,mode of delivery, diet (cow milk formula, breast milk), hygiene, and medicationused. He added that there is a limited knowledge of the diversity of human intestinalmicrobial flora and diversity of these organisms is important. Microflora areeffected by acute infection, antimicrobial agents, cancer and inflammatory disease.He added that researchers still have a lot to learn with respect to infants andselect groups. There are so many different strains of probiotics that we stilldo not know what strain works best. Mothers milk has many different microflora,and this is one of the reason’s for its beneficial effects. Researchersare asking should we use one or more strains, or concentrate the microbes, thisis a discussion taking place among many experts. What they do know is that probioticsdo seem to work, in reducing diarrhea in children with acute enterocolitis. Probioticsare effective in the lumen of the gut, increase the integrity of the barrier,and enhance the effect of T reg cells in the mucosa. There are however, lots ofchallenges for use in children such as maintaining stability, delivery, frequencyand safety. Dr Walker noted that although it looks like probiotics are effective,researchers need to develop a single protocol, with a a specified amount, givenat the same time in order to build the case for real evidence of the effects ofprobiotics. Researchers are looking at the manipulation of microbes in pregnantmothers during the neonatal development period, the association of obesity andcertain microbes in the GI tract. Relationships have been shown to exist betweeninfection, antibiotic use and diseases such as Crohns and MS.