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Microflora in Health and Disease
Human host and its microbial flora constitute a complex ecosystem whose equilibrium serves as a remarkable example of reciprocal adaptation. Bacterial omeostasis conditions, also known as eubiosis, is stably maintained in healthy individuals despite a dynamic evolution of gut microbiota occurs during human life, from infancy to elderly.
Intestinal bacteria play an important role in the development of the immune system. The normal intestinal flora is responsible for resistance to colonization by exogenous pathogenic microorganisms. Nevertheless, it also constitutes a reservoir of potentially pathogenic bacteria in close contact with the host. These bacteria are responsible for opportunistic infections in immunocompromised hosts. The equilibrium of the flora can be upset by antibiotics, leading to infections as a result of proliferation of antibiotic-resistant detrimental bacteria. The human gut is the natural habitat for a large and dynamic bacterial community, but a substantial part of these bacterial populations are still to be described. However, the relevance and the effect on host’s physiology have been well documented. Major functions of the gut microflora include metabolic activities that result in salvage of energy and absorbable nutrients, important trophic effects on intestinal epithelia and on immune structure and function, and protection of the colonised host against invasion by alien microbes. Gut flora might also be an essential factor in certain pathological disorders, including multisystem organ failure, colon cancer, and inflammatory bowel diseases. Nevertheless, bacteria are also useful in promotion of human health. Probiotics and prebiotics are known to have a role in prevention or treatment of some diseases.
The primary interest in the application of probiotics has been in the prevention and treatment of gastro-intestinal disorders. The general mechanisms by which probiotics may have an effect are normalisation of the gut microbiota, modulation of immuno-responses and/or metabolic functions.
Alterations in gut eubiosis is frequently associated (disbiosys or dismicrobism) with an enhanced risk of specific diseases. Modulation of the unbalanced microbiota represents the rational for the use of probiotics.
The main fields of probiotics and prebiotics application in treatment of human diseases are summarised below:
- Lactose maldigestion
- Oral infections and dental caries
- Diarrhea (from rotavirus, antibiotic-associated, from Clostridium difficile, from radiation, traveller's diarrhea)
- Irritable bowel syndrome
- Inflammatory bowel disease
- Helicobacter pylori infection
- Post-operative infections
- Respiratory tract infections
- Allergic diseases
- Cancer
- Serum cholesterol
- Vaccine response
AAT performs research activities about pro- and prebiotic application to human diseases by collaborating with academic and clinical research centres to identify biomarkers to be used in the diagnosis and evaluation of the role of nutrients, to evaluate the nature of disbiosys associated to human diseases, to evaluate the impact of pre- and probiotics on gut microflora of patients.
For more info please address to the following publications:
- Biasucci G, Benenati B, Morelli L, Bessi E, Boehm G. (2008) Cesarean delivery may affect the early biodiversity of intestinal bacteria. J Nutr. Sep;138(9):1796S-1800S
- M. Elli, E. Bessi, D. Cattivelli, S. Soldi and L. Morelli (2005) Evidence-based impact of prebiotics and probiotics on gut microflora. The role of molecular biology. Nutrafoods 4(2-3): 37.
- Editorial in Reference Probiotique - Yoghurts & Fermented Milk. Produced by the scientific commettee of Syndifrais. The fate of probiotics in the digestive tract. Letter n. 30, December 2006.
- Marina Elli, Lorenzo Morelli (2008) Bulk-forming agent psyllium fibre. Influence on faecal microbiota of healthy women determined by molecular monitoring. Nutrafoods 7(1) 27-32.
(From: Maukonen 2006, profile of the human fecal microflora as obtained by DGGE).