Epithelial microbiota

Howard, M.D., Gordon, D.T., Pace, L.W., Garleb, K.A., and Kerley, M.S., Effects of dietary supplementation with fructooligosaccharides on colonic microbiota populations and epithelial cell proliferation in neonatal pigs, J. Pediatr. Gastroenterol. Nutr., 21, 297-303, 1995. 

There is increasing evidence that the interaction between the intestinal microbiota and the intestinal epithelial and immune cells plays a key role in the postnatal development of the immune system. First studies with probiotics (74) and synbio-tics (40) demonstrate effects during infancy, and studies regarding the vaccination response in the elderly (75) indicate that the prebiotics might also influence the immune system. In particular, the animal experiments with prebiotics described above allow the hypothesis that prebiotics that are able to influence the composition of the entire intestinal microbiota toward microbiota found in breastfed infants might support the development of the immune system during infancy. 

A number of reviews and studies have been published dealing with the potential health and nutritional benefits of EPSs from LAB in fermented dairy products for example, EPSs from LAB have been associated with various health benefits, such as the lowering of cholesterol (Liu et al., 2006 Maeda, Zhu, Omura, Suzuki, Kitamura, 2004 Nakajima, Suzuki, Hirota, 1992), anti-hypertensive effects (Maeda, Zhu, Suzuki, Suzuki, Kitamura, 2004), anticarcinogenic effects (Furukawa, Takahashi, Yamanaka, 1996 Kitazawa et al., 1991) and immunomodulatory activity (Chabot et al., 2001 Nishimura-Uemura et al., 2003 Vinderola, Matar, Palacios, Perdigon, 2007). Apart from these effects, there also appears be a complex web of interactions between LAB EPSs and human gut microbiota, some enteric pathogens and toxins, and gut epithelial cells and the immune system the discussion that follows presents evidence for health and nutritional benefits that are potentially derived from these relationships. 

First contact between the intestinal microbiota and the host occurs via mucosal ECs (or modified epithelial cells called M cells in the Peyer s Patches), and underlying or intercalating DCs. Mucosal ECs express polymeric immunoglobulin receptor (PigR) and secretary component, MHC class I and II molecules, other adhesion molecules and a variety of cytokines and chemokines. These molecules play important roles in signaling microbial... 

Wells JM, Rossi O, Meijerink M, van Baarlen P. Epithelial crosstalk at the microbiota—mucosal interface. Proc Natl Acad Sci USA. 2011 108 (suppl 1) 4607-4614. 

In a recent work with healthy volunteers, black raspberry anthocyanins could be detected under their hydrolyzed aglycone form in the oral cavity, resulting from the activity of B-glycosidase derived both from bacteria and oral epithelial cells [40]. In the same study, parent anthocyanins and cyanidin-3-glucoside microbiota metabolite, protocatechuic acid, were detected in the saliva. Furthermore, saliva samples contained glucuronidated anthocyanin conjugates, consistent with intracellular uptake and phase II conversion of anthocyanins [40]. 

The intestinal ecosystem is a complex microenvironment constituted by eukaryotic and prokaryotic cells where a complex network of signals that maintain the intestinal homeostasis is established. The gut microbiota is an important component of this ecosystem commensal bactaia are key players participating in the digestion process, vitamin synthesis, and other metabolite production (bile acids, lipids, amino acids, and short-chain fatty acids), which are important for maintaining health in mammals (Brestoff and Artis 2013). However, it is known that the commensal microbiota is not in direct contact with the epithelial cells due to the presence of the mucus layer (Johansson et al. 2011). 

The balance and composition of microbiota is extremely important to modulate the immune system and to influence the development and physiology of the host (Brestoff and Artis 2013). During stress, permeability and the intestinal barrier function are altered. Probiotics are able to reinforce the epithelial barrier, as was demonstrated by different studies (Zareie et al. 2006 Ait-Belgnaoui et al. 

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