The Third International Congress of Translational Research in Human Nutrition (ICTRHN) took place in Clermont-Ferrand, France, on June 26 & 27, 2015.
This post is an overview of the final ICTRHN symposium on clinical implications.
(See here and here for the rest of the GMFH coverage of ICTRHN.)
- Prof. Karine Clément, Institute of Cardiometabolism and Nutrition, France — Microbiota in cardiometabolic diseases
Clément opened by emphasizing how costly cardiometabolic diseases are to society. Turning to the microbiota, she said that research has found bacterial metabolites such as SCFAs, TMA/TMAO, as well as bacterial components (LPS) contribute to these diseases.
She says a rapid increase in gene richness is found after Roux-en-Y gastric bypass (RYGB), with major changes occurring in the microbiota from before surgery to 3 months and 6 months after surgery. Increased enterobacteria are seen both in humans and animal models; the changed bacterial taxa are those associated with improved metabolic phenotype.
Food intake behavior, pH, bile acids, incretins, and transit are all altered after RYGB. Yet not all patients respond the same to RYGB, and some will regain weight in the long run. Clément then covered some of the previously-found associations between cells, bacteria, and cardiometabolic phenotypes, concluding that the patient’s ecosystem matters for cardiometabolic risk.
- Prof. Brent Polk, University of Southern California, USA — Probiotics and Prebiotics in health and disease: Mechanisms of action and therapeutic implications
Polk says probiotics are a popular topic, but that on the whole we only have pre-clinical data. Many trials are published but we still have little mechanistic understanding. Challenges in probiotic and prebiotic studies include:
– Not all probiotics and prebiotics are created equally
– Bioavailability (survival, location, function) varies
– Biosafety (identifying risk groups)
Research topics include how probiotics and prebiotics regulate intestinal epithelial homeostasis and/or barrier function, how they proliferate, whether and how they migrate, under which conditions the cells survive, how they impact innate and adaptive immunity, and how they affect their microenvironment.
Polk says barrier function is relevant for acute gastroenteritis, necrotizing enterocolitis, and atopy. He covered mouse studies that showed effects of probiotics on intestinal permeability, with some positive and some negative trials in humans. Certain probiotics may protect against colitis in mouse models.
- Prof. Bernd Schnabl, University of California San Diego, USA — Microbiota and liver diseases
Schnabl reminded us that excess alcohol consumption leads to steatosis (along with steatohepatitis), then fibrosis, cirrhosis (end stage liver disease) and perhaps liver cancer. Once hepatitis C is controlled, these liver diseases will be the number two reason for liver transplant.
Schnabl says we have long known patients with alcoholic liver disease have small intestinal bacterial overgrowth — both aerobic and anaerobic, and throughout the gut from proximal small intestine to cecum. It is less clear whether this occurs in the colon. Recent data showed that the microbiota profile potentially distinguished more and less severe conditions. Fecal lactobacilli are decreased in this population, and intestinal permeability is increased compared to controls.
Moving on to therapeutic interventions, Schnabl covered the potential of non-absorbable antibiotics, prebiotics, and probiotics to affect liver disease.