Gut microbes and man：What’s new in this 2 million year affair?
|演者||Farthing Michael JG（United European Gastroenterology（UEG）/Department of Medicine, University of Sussex, UK）|
|抄録||The evolution of the intimate relationship between prokaryote bacteria, the first form of life on earth（3.5 billion years ago）and man began about 2.5 million years ago. This population of bacteria in the gut（the microbiota）out-number the total population of eukaryote cells in the human organism by a factor of 10, consist of about 1000 different species and possess 100-fold more genes than that found in the human genome. The microbiota plays a vital role in gut development particularly of the immune system.
The importance of this symbiotic relationship has been debated for more than a century. However genetic characterisation of the gut microbiota has led to an explosion of knowledge in last decade indicating that its disruption（dysbiosis）may be highly relevant to the causation of a range of GI diseases（IBD, IBS, cancer, antibiotic-related diarrhoea, etc.）and systemic disorders such as diabetes, obesity and malnutrition. The potential to manipulate the gut microbiota is growing rapidly with increasing evidence for the value of probiotics and prebiotics, targeted use of antimicrobials and reconstitution by faecal transplantation. Currently these approaches are imperfect and the future challenge will be to use molecular genetic techniques to increase their potency.
The human gut is also vulnerable to an extensive range of pathogenic bacteria, viruses and protozoa that are still responsible for 1-2 million deaths each year globally. Many of the pathogenic bacteria are closely related to counterparts in the microbiota but have evolved‘smart’virulence factors that cause secretion, permit invasion and perturbation of the epithelium and sometimes systemic infection. Immune mediated effects can extend beyond the gut and affect other systems. Rapid molecular diagnostic techniques are more widely available but antibiotic resistance will produce major challenges in the near future. Vaccine development for the prevention of intestinal infection has been slow and large gaps remain in the pathogenic spectrum. Manipulation of the microbiota may offer important therapeutic opportunities in the future to control intestinal infection.