Effect of probiotic bifidobacterium,the organs which supply enzymes needed for starch digestion include,probiotics 2015 omics group - PDF Books

Natural Marketing Institute’s (NMI) Health and Wellness Trends Survey (2008 HWTD) reported that U.S. Probiotics are live microorganisms that are similar to beneficial microorganisms found in your gastro intestinal tract.
A healthy lower intestine should contain at least 80-85% friendly bacteria or probiotics to prevent growth of disease causing micro-organisms like E.
Poor eating habits, chlorinated drinking water, stress, use of antibiotics, medical treatments can destroy the gastrointestinal micro flora and allow harmful bacteria to multiply.  Thus, make the body susceptible to yeast and bacterial infection and other disorders including gas, cramping, or diarrhea. Probiotic supplements contain millions to billions of live bacteria to bolster and replenish levels of health promoting good microbes in your digestive tract. Probiotic products are available in different formulations with Lactobacillus acidophilus, Bifidobacterium longum, Bifidobacterium infantis, Enterococcus faecium and other beneficial bacteria. The most numerous probiotic bacteria normally present in the small intestine are species of Lactobacilli. Probiotics are already present in our normal digestive system and generally recognized as safe (GRAS). Before launching ofActivia probiotics were known by a small percentage of the population and natural product shoppers and healthcare professionals.But this is a good product for general good health.
The probiotic bacteria used in commercial productstoday are largely members of the genera Lactobacillus and Bifidobacterium.
To understand why probiotics are important, we first need to understand how valuable beneficial bacteria are to our health, and how prevalent they are in our bodies.
In our gut, good bacteria can displace bad bacteria and influence our overall health, metabolism, digestion, and body composition. Gut bacteria are involved in immunity and help to ensure our immune system doesn’t have an itchy trigger finger (think food sensitivities). Adequate consumption of probiotics can help to eliminate abdominal pain, gas, bloating, reflux, allergies, nausea, food poisoning and vomiting. While our intestinal bacteria are pretty tough little critters, their health can be compromised. And speaking of diet, if you eat animal foods, the gut health of the animal is important too. Probiotics are found in yogurt, buttermilk, kefir, sauerkraut, kimchi, and bacterially cultured cheese. As with all products containing living bacteria,probiotic products must be cooled during storage. Probiotics seem to improve overall health, metabolism, immunity, digestion, and body composition. If you are healthy, aim for 1-2 servings of probiotic rich foods each day (use the food source list above). If you are healthy, aim for 2-3 servings of prebiotic rich foods each day (use the food source list above). Take note: You may actually feel worse before you feel better since bacteria release toxins. In it you’ll learn the best eating, exercise, and lifestyle strategies — unique and personal — for you. Science, Technology and Medicine open access publisher.Publish, read and share novel research. Lactic Acid Bacteria as Probiotics:Characteristics, Selection Criteria and Role in Immunomodulation of Human GI Muccosal BarrierDaoud Harzallah and Hani Belhadj[1] Laboratory of Applied Microbiology, Faculty of Natural and Life Sciences, University Ferhat Abbas, Setif, Algeria1. A weblog on the sciences and practices of living healthily very long – perhaps hundreds of years. There is strong and widespread current interest in gut microbiota and I have found thousands of relevant research publications related to gut microbiota.  My purpose here it to introduce the topic in this blog, to establish its relevance, and to identify some recent key research findings. Aging of a human happens in a meta-organism consisting not only of that person’s body and cells but also of the 100 trillion organisms that exist in that persons gut.
The 2009 publication Acquisition, evolution and maintenance of the normal gut microbiota reports: “The gut is sterile at birth, but is rapidly colonised by faecal and vaginal bacteria of maternal origin.
From Genomic Insights into Bifidobacteria: “The human large intestine is a very complex ecosystem that is still not fully understood, and while its microbial composition consists primarily of just four bacterial phyla, Bacteroidetes, Firmicutes, Actinobacteria, and Proteobacteria (as well as some Archaea, Eukarya, and viruses), it is highly variable at the genus level between individuals, likely due to factors such as age, health, diet, etc. The 2007 publication Intestinal bacteria and ageing reported: “Advancements in science and medicine, as well as improved living standards, have led to a steady increase in life expectancy, and subsequently a rise in the elderly population. The 2010 publication Role of the gut microbiota in defining human health reported: “The human superorganism is a conglomerate of mammalian and microbial cells, with the latter estimated to outnumber the former by ten to one and the microbial genetic repertoire (microbiome) to be approximately 100-times greater than that of the human host. While the study of gut bacteria has been going on for more than 100 years, many new insights are now flowing from massive genomic sequencing techniques. Bifidobacteria appear to be an important set of species of gut bacteria from a health viewpoint.
Gut microflora may play an even more important role in maintaining human health than previously thought.  Specifically it appears they are involved in the control of energy and metabolic homeostasis. This theme has been repeated in a substantial number of publications for over five years now. The August 2011 publication Programming of host metabolism by the gut microbiota reports: “The human gut harbors a vast ensemble of bacteria that has co-evolved with the human host and performs several important functions that affect our physiology and metabolism. The mixture of kinds of bacteria in the gut may contribute to metabolic disorders such as obesity, diabetes, and cardiovascular diseases or can contribute strongly to maintenance of health homeostasis. The November 2010 publication Ecology and Physiology of the Intestinal Tract reports: “The number of microorganisms inhabiting the human digestive tract exceeds the number of body cells by a factor of ten.
The January 2012 publication Is the gut microbiota a new factor contributing to obesity and its metabolic disorders?
A discussion of the role of gut flora in autism and inflammatory bowel disease can be found on this webpage of science-autism.org which is about published scientific data concerning autism. Image from Gut Flora in Autism:  “A well considered pathway for the effect of bacterial flora on the inflammatory response of the gut wall in IBD. With advanced aging, changes typically happen in the ecology of the gut microorganism, system resulting in increased susceptibility to infectious diseases and related infirmities. On the other hand, the 2010 e-publication Human intestinal microbiota and healthy ageing review publication reports: “Earlier studies have indicated a decrease in anaerobes and bifidobacteria and a concomitant increase in enterobacteria in the intestinal microbiota with ageing. TLR and NLR signaling in intestinal epithelial cells triggered by gut microbiota contribute to a range of homeostatic mechanisms including proliferation, wound healing, epithelial integrity, and regulation of mucosal immune functions. The 2010 publication The role of innate signaling in the homeostasis of tolerance and immunity in the intestine reports: “In the intestine innate recognition of microbes is achieved through pattern recognition receptor (PRR) families expressed in immune cells and different cell lineages of the intestinal epithelium. Our old friend NF-kappaB can be activated by TLR and NOD signaling by gut microbiota, resulting in possible positive or detrimental effects. The 2010 publication Role of NF-kappaB activation in intestinal immune homeostasis reports: “Inflammatory bowel diseases (IBD) are characterised by a disturbance of intestinal immune homeostasis, either caused by or followed by inappropriate responses to the resident commensal bacteria. The May 2011 publication Influence of gastrointestinal commensal bacteria on the immune responses that mediate allergy and asthma reports: “The human intestine contains more than 100 trillion microorganisms that maintain a symbiotic relationship with the host. Raising bifidobacteria levels by the use of probiotics and prebiotics appears to be the most-established strategy for modifying microbial balance in human colons to promote health.  However, much remains to be learned. The December 2009 publication Food-based strategies to modulate the composition of the intestinal microbiota and their associated health effects reports: “The most well known food-based strategies to modulate the composition of the intestinal microbiota are the dietary use of prebiotics, probiotics and their combination, synbiotics.
Prebiotics may be useful for the prevention or treatment of insulin resistance, diabetes and obesity.
The 2011 publication Gut microbiota and the pathogenesis of insulin resistance reports: “Several reviews recently explored how the gut microbiota was able to control host energy metabolism, and thereby the development of adiposity. The LKM512 strain of yogurt bacteria has attracted particular attention as a probiotic for increasing polyamines levels and inhibiting inflammation. The 2009 publication Polyamine-rich food decreases age-associated pathology and mortality in aged micerelates polyamine consumption to senescence markers in mice: “The purpose of this study was to test whether oral intake of foods rich in polyamines (spermine and spermidine) suppresses age-associated pathology in aged mice.
The 2009 publication Dynamics of fecal microbiota in hospitalized elderly fed probiotic LKM512 yogurt reports: “The comprehensive dynamics of intestinal microbiota including uncultured bacteria in response to probiotic consumption have not been well studied.
Some researchers think targeting the gut microbiota may be an avenue for human life extension. While this discussion is theoretical, it does appear that life extension in mice is possible by feeding them probiotics.
I was motivated to research and generate this blog entry by coming across the August 2011 publication Longevity in mice is promoted by probiotic-induced suppression of colonic senescence dependent on upregulation of gut bacterial polyamine production.
Scientists at the University of Arizona believe the microbes living in a dog's gut may be good for their owners' health. A healthy and diverse population of these good bacteria are key to proper functioning of our digestive and immune systems, greatly impacting our physical and mental health. (1, 2, 3, 4).
We can improve the population of good bacteria in our guts thru proper nutrition, and by taking Probiotic supplements.
We humans carry around 10 times as many microorganisms with us as we have cells in our body.  (5). They are most prominent in  the stomach and intestinal tract where they aid nutrient absorption and  immune system and are referred to as our gut flora or gut microbiome. There are hundreds  of strains   of these friendly bacteria that aid digestion and produce important nutrients, including B and K vitamins. Modern agricultural practices including  rampant use of pesticides, chlorine soaking,  preservatives and refrigeration   leave our foods have very little probiotics today. In fact, some foods now have dangerous antibiotics that destroy the bacteria in our digestive system. Our foods, environment, stresses and medicines can all damage the biology in our guts and wreak havoc on our health. The biology of our guts is not static, and can be changed by diet and outside environmental factors(12). Bacteroidetes and firmicutes are the 2 main families of bacteria that are important for regulating bodyweight by digesting  fatty acids and dietary polysaccharides. The functions of the hundreds of different strains of bacteria are complex and not entirely understood, with some disagreement among researchers (7, 8). Prevotella  is a enterotype, or  family of bacteria strain that help digest carbohydrates and are more prevalent in people who consume a lot of carbohydrates. Bacteroides are another family of bacteria that is more prevalent in people who consume significant amounts of animal protein.
Increasing the population of certain strains of bacteria is now thought to effect how our bodies process and store food, which can affect weight.
An early sign of this was a study where gut bacteria from obese mice that are transplanted into the guts of normal weight mice result in those mice soon becoming obese (13). Minimising low-grade inflammation, one of the main drivers behind metabolic disease, is the primary suspect (14, 15, 16).
In people, studies show that those who are overweight  have much different populations of bacteria  than people of normal weight (17, 18). Those studies show normal weight people have more bacteroidetes, and fewer firmicutes than overweight people. (19, 20).
These results opened up some very exciting possibilities for weight loss to see how much we can alter our gut bacteria to help cure obesity.
Studies have found that certain strains of the Lactobacillus family can help you lose weight and belly fat. In one study, eating yogurt with Lactobacillus fermentum or Lactobacillus amylovorus reduced body fat by 3–4% over a 6-week period (21).
Another study of 125 overweight dieters investigated the effects of Lactobacillus rhamnosus supplements on weight loss and weight maintenance (22).
During a 3-month study period, the women taking the probiotics lost 50% more weight compared to the group taking a dummy pill (placebo).
Note that int these 2 studies mentioned above subjects were provided with Prebiotics along with the LG (Yoghurt and Inulin) which is thought to improve the effectiveness. Lactobacillus gasseri is generating the most excitement and further research for its  effects on weight loss. There have been several mouse studies that showed positive results for weight control (25, 26, 27, 28). Subject were given a glass of fermented milk to drink every day, with half including Lactobacillus gasseri in their drink and the other half not. Testing of fecal samples before and after the study showed those receiving Lactobacillus gasser had a higher amount of fat in the feces after the 2 weeks, while the control group did not (29). Effect of intake of fermented milk containing Lactobacillus gasseri on fecal fat excretion in humans. This proved that not only does the Lactobacillus gasseri survive the digestive process, but that it had an effect on the metabolism, resulting in less fat being absorbed.
An earlier Japanese study showed Lactobacillus gasseri can effectively reduce waist size, BMI and the dangerous visceral fat that accumulates around the organs (30). Some strains of the Lactobacillus family have been shown to reduce weight and belly fat. Lactobacillus gasseri appears to be the most effective. Kombucha, Kefir, yoghurt and pickled vegetables like kimchi, sauerkraut are good sources of a wide variety of Lactobacillus strains.
Lactobacillus gasseri is also found naturally in breast milk, which is thought to help the development of an infant’s immune system.
It has been used extensively for 15 years, primarily for relief of IBS and other chronic gastric distress problems. As for weight control, a 2015 study tested 20 normal weight men to see the effects of VSL#3 in conjunction with a high fat diet. This particular blend of probiotic strains was shown to protect against weight gain in test subjects who were fed 1000 calories more per day than required (31).
Losing weight justifiably receives the most interest, but preventing weight gain is sometimes important to prevent regain of lost weight after prolonged dieting. Oral supplementation of some strains clearly effect the population of our gut bacteria and can be help improve the digestive process. Lactobacillus Gasseri is the most effective probiotic strain for weight loss identified so far. There are several brands on Amazon that include some L Gasseri in combination with 10 or more other strains. VSL#3 has long been a popular choice for relief of many gastric distress issues and appears to  be beneficial in preventing weight gain. Besides weight loss, a healthy microbiome can have improve digestive health, reduce inflammation, improve cardiovascular risk factors and even help fight depression and anxiety. As always, we recommend a low carb diet and more exercise as the most effective way to lose weight. If you extracted all of the microbes that live in your body, you’d have over a quart of sludge.
Scientists estimate that we have over 50 genera of bacteria that provide over 500 different species! Probiotics may even alleviate irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and dermatitis.
When good bacteria flourish, bad bacteria and other micro-organisms such as yeasts and fungi are pushed out. Traditional methods of meat preservation (such as the curing of salami) also use fermentation of Lactobacilli to preserve the food, although arguably industrially produced cured meats no longer have health benefits. Fermentation intensifies the stimulant properties of the leaves and produces black and oolong varieties.
We don’t digest prebiotics, which come mainly from oligosaccharides (complex starches), but probiotics love them. If you’re hoping to prevent or alleviate a medical problem, you may need to increase the dose.
Digestive enzymes are like chemical grinders that chew up substances and break them down for us so we can absorb them.
Traditional food-processing and preparation practices to enhance the bioavailability of micronutrients in plant-based diets.
The role of diet- and host-related factors in nutrient bioavailability and thus in nutrient-based dietary requirement estimates. Probiotic modulation of symbiotic gut microbial-host metabolic interactions in a humanized microbiome mouse model. Probiotic food supplement reduces stress-induced gastrointestinal symptoms in volunteers: a double-blind, placebo-controlled, randomized trial.
The utility of probiotics in the treatment of irritable bowel syndrome: a systematic review. Probiotic-induced changes in the intestinal epithelium: implications in gastrointestinal disease. Probiotic safety in pregnancy: a systematic review and meta-analysis of randomized controlled trials of Lactobacillus, Bifidobacterium, and Saccharomyces spp. IntroductionAs it was reported by Chow (2002), the notion that food could serve as medicine was first conceived thousands of years ago by the Greek philosopher and father of medicine, Hippocrates, who once wrote: 'Let food be thy medicine, and let medicine be thy food'.
Epithelial cells lining the gastrointestinal tract are able to respond to infection by initiating either nonspecific or specific host-defence response (Kagnoff and Eckmann 1997, Strober 1998).
This assumption imposes a more holistic view of the ageing process where dynamics of the interaction between environment, intestinal microbiota and host must be taken into consideration. Over the succeeding weeks, months and years, a complex microbiota develops that plays a major role in host physiology. The intestinal microbiota is important for maintenance of host health, providing energy, nutrients and protection against invading organisms. Given the ability of the immune response to rapidly counter infectious agents, it is striking that such a large density of microbes can exist in a state of synergy within the human host. Identification of Bifidobacteria goes back to 1900.  Also from the September 2010 publication Genomic Insights into Bifidobacteria “Tissier (315) suggested that the large number of bifidobacteria in the feces of healthy breast-fed infants was likely the reason for their lower incidence of infantile diarrhea. The 2007 reviewpublication Gut microflora as a target for energy and metabolic homeostasis reported “Purpose of review: Gut microbiota plays an important role in health and disease, but this ecosystem remains incompletely characterized and shows a wide diversity.
The human gut is sterile at birth and is subsequently colonized with bacteria from the mother and the environment.
Relates: “The gut microbiota refers to the trillions of microorganisms residing in the intestine and is integral in multiple physiological processes of the host. We observed that the microbial composition and diversity of the gut ecosystem of young adults and seventy-years old people is highly similar but differs significantly from that of the centenarians.
However, new data obtained with molecular techniques suggests decreased stability and increased diversity of the gut microbiota with advancing age. Toll-like receptor (TLR) and nucleotide-binding and oligomerization domain-like receptor (NLR) families are emerging as key mediators of immunity through their role as maturation factors of immune cells and triggers for the production of cytokines and chemokines and antimicrobial factors. Under normal conditions, these bacteria are not pathogenic and in fact confer health benefits to the host.


By far the most important predominant populations are in the colon where a true symbiosis with the host exists that is a key for well-being and health. Currently established prebiotic compounds are mainly targeting the bifidobacteria population of the colon microbiota. In this review, we focused on the state of the art that supports a link between the gut microbiota composition and activity, and the management of glycemia associated with overweight and diabetes.
Synthetic polyamines were mixed into experimental chows, and 24-week-old Jc1:ICR male mice were fed one of three chows containing differing polyamine concentrations. The aims of this study were twofold: firstly to analyze the impact on intestinal microbiota of yogurt fermented by Bifidobacterium animalis subsp. During evolution, an integrative circuitry fundamental for survival has been established between commensal gut microbiota and host.
For example, fermented foods such as Yoghurt and Kefir are sources of beneficial bacteria, a probiotic, which your body requires for health.
This could be increased to 10 billion if you are hoping to alleviate a specific health concern.
Potential and established health benefits associated with the usage of probiotics (Leroy et al., 2008). However, during recent times, the concept of food having medicinal value has been reborn as 'functional foods'. Bacterial adhesion to the host cell or recognition by the host cell is often an essential first stage in the disease process. While the digestive tract is colonised to varying degrees by micro-organisms throughout its length, due to acid pH and the short retention time of gastric contents, bacterial numbers in the stomach are usually low.
Although the colonic microbiota is relatively stable throughout adult life, age-related changes in the gastrointestinal (GI) tract, as well as changes in diet and host immune system reactivity, inevitably affect population composition. This is particularly true of the distal gastrointestinal (GI) tract, which houses up to 1000 distinct bacterial species and an estimated excess of 1 x 10(14) microorganisms. In his pediatric work, he used bifidobacteria for the treatment of this intestinal diarrhea, and this likely represents the first example of the oral administration of a live microorganism for the treatment of a disease (316).
The complexity of the gut microbiota is increased during childhood, and adult humans contain 150-fold more bacterial genes than human genes. The metabolic potential of the gut microbiota is immense affording the extraction of energy from otherwise indigestible carbohydrates (dietary fiber) and the conversion of host-derived substances, non-nutritive dietary components and drugs.
Recent research has shown that gut bacteria play a role in metabolic disorders such as obesity, diabetes, and cardiovascular diseases. After 100 years of symbiotic association with the human host, the microbiota is characterized by a rearrangement in the Firmicutes population and an enrichment in facultative anaerobes, notably pathobionts. At the mucosal surface chronic activation of the immune system is avoided through the epithelial production of a glycocalyx, steady-state production of antimicrobial factors as well as the selective expression and localization of PRRs.
The enormous amount of commensal bacteria in the intestine might play a role in the distinct functions of NF-kappaB in the intestine, as they can initiate signalling to NF-kappaB through both Toll-like receptors and NOD-like receptors in intestinal epithelial cells as well as mucosal immune cells. The microbiota interacts with the innate and adaptive arms of the host’s intestinal mucosal immune system and through these mechanisms drives regulatory cell differentiation in the gut that is critically involved in maintaining immune tolerance. Several microbial-derived compounds are related to disturbances of glucose homeostasis including the gram-negative-derived lipopolysaccharides. On the basis of recent knowledge in worms, flies, and humans, an important role of the gut microbiota in aging and longevity is emerging.
In mammals, levels of polyamines (PAs) decrease during the ageing process; PAs are known to decrease systemic inflammation by inhibiting inflammatory cytokine synthesis in macrophages.
For a right dose and selection of probiotics, I would encourage you to discuss with a personal health professional. Fermentation organisms produce alcohol, lactic acid, and acetic acid, preservatives that retain nutrients and prevent spoilage. Key and desirable criteria for the selection of probiotics in commercial applications (Vasiljevic and Shah, 2008).
The list of health benefits accredited to functional food continues to increase, and the gut is an obvious target for the development of functional foods, because it acts as an interface between the diet and all other body functions. A wide range of gastrointestinal cell surface constituents, such as several glygoconjucates, can serve as receptors for bacterial adherence (Servin and Coconnier 2003, Pretzer et al., 2005).
Here we review the current knowledge of the changes occurring in the gut microbiota of old people, especially in the light of the most recent applications of the modern molecular characterisation techniques.
The rapid passage of digestive materials through the upper gut does not provide time for significant bacterial growth to occur, but cell numbers increase considerably in the distal ileum. Recent studies indicate shifts in the composition of the intestinal microbiota, which may lead to detrimental effects for the elderly host.
An ever-increasing body of evidence implicates the GI microbiota in defining states of health and disease.
The abundance of bifidobacteria in the feces of breast-fed infants was thought to be due to the Bifidobacterium-stimulating properties of human breast milk (38, 46, 60, 96, 196, 321). Recent advances in next-generation sequencing technology and mechanistic testing in gnotobiotic mice have identified the gut microbiota as an environmental factor that contributes to obesity.
Recognized functions of the gut microbiota include provision of colonization resistance against pathogens and priming of both the innate and the acquired immune systems. The presence of such a compromised microbiota in the centenarians is associated with an increased inflammatory status, also known as inflammageing, as determined by a range of peripheral blood inflammatory markers. Except for the reduced immune function, ageing itself may have relatively little effect on overall gastrointestinal function.
Additionally, the polarization of epithelial TLR signaling and suppression of NF-kappaB activation by luminal commensals appears to contribute to the homeostasis of tolerance and immunity. However, the exact individual contributions of different NF-kappaB-activating stimuli as well as the target cells that mediate the detrimental or beneficial functions of NF-kappaB in the intestine are still elusive. Specifically, the microbiota can activate distinct tolerogenic dendritic cells in the gut and through this interaction can drive regulatory T-cell differentiation. The present document has been written by a group of both academic and industry experts (in the ILSI Europe Prebiotic Expert Group and Prebiotic Task Force, respectively). Some nutrients with prebiotic properties, which escape the digestion in the upper part of the gut, modify the composition of the gut microbiota in favor of bacteria that could play a beneficial role on glucose homeostasis, namely by modulating the endocrine function of the gut, and by reinforcing the gut barrier.
An increase in concentration of polyamine in the blood was found only in mice fed the high polyamine chow at 50 weeks of age. The complex bacterial community that populates the gut and that represents an evolutionary adapted ecosystem correlated with nutrition appears to limit the accumulation of pathobionts and infections in all taxa, being able of affecting the efficiency of the host immune system and exerting systemic metabolic effects. Reductions in intestinal luminal PAs levels have been associated with intestinal barrier dysfunction. One of the most promising areas for the development of functional food components lies in the use of probiotics and prebiotics which scientific researches have demonstrated therapeutic evidence.
Furthermore, epithelial cells express constitutively host pattern recognition receptors (PRRS), such as Toll-like receptors (TLR). The hypothetical involvement of the age-related gut microbiota unbalances in the inflamm-aging, and immunosenescence processes will also be discussed. The rate of movement of intestinal contents slows in the colon, which facilitates the development of complex bacterial communities. Increased numbers of facultative anaerobes, in conjunction with a decrease in beneficial organisms such as the anaerobic lactobacilli and bifidobacteria, amongst other anaerobes, have been reported. Recent data suggest that the modulation of gut microbiota affects host metabolism and has an impact on energy storage.
Germ-free mice are protected against developing diet-induced obesity and the underlying mechanisms whereby the gut microbiota contributes to host metabolism are beginning to be clarified. However, the intestinal microbiota may also contribute to the development of diseases such as ulcerative colitis and colorectal cancer. Gut microbiota has evolved with humans as a mutualistic partner, but dysbiosis in a form of altered gut metagenome and collected microbial activities, in combination with classic genetic and environmental factors, may promote the development of metabolic disorders.
Concomitant changes in nutrition, increased incidence of disease and corresponding use of medication with advancing age modify the composition of the microbial community of the gastrointestinal tract. Several studies have demonstrated that TLR signaling in epithelial cells contributes to a range of homeostatic mechanisms including proliferation, wound healing, epithelial integrity, and regulation of mucosal immune functions. In addition, the microbiota is important in driving T(H)1 cell differentiation, which corrects the T(H)2 immune skewing that is thought to occur at birth.
Interestingly, the changes in the gut microbes can be reversed by dieting and related weight loss.
While the body weights of mice in all three groups were similar, the survival rate of mice fed high polyamine chow was significantly higher than those in the other two groups (p=0.011).
There is an urgent need to disentangle the underpinning molecular mechanisms, which could shed light on the basic mechanisms of aging in an ecological perspective. Nowadays, consumers are aware of the link among lifestyle, diet and good health, which explains the emerging demand for products that are able to enhance health beyond providing basic nutrition. The large intestine is an intricate ecosystem that contains a complex microbiota composed of several hundred different types of bacteria. These changes, along with a general reduction in species diversity in most bacterial groups, and changes to diet and digestive physiology such as intestinal transit time, may result in increased putrefaction in the colon and a greater susceptibility to disease. The obese phenotype is associated with increased microbial fermentation and energy extraction; however, other microbially modulated mechanisms contribute to disease progression as well. Culture-dependent studies provided basic knowledge on the gut microbiota, but only the advent of culture-independent molecular methods led to a better understanding of host-microbe interactions. If appropriate immune tolerance is not established in early life and maintained throughout life, this represents a risk factor for the development of inflammatory, autoimmune, and allergic diseases. A large number of human intervention studies have been performed that have demonstrated that dietary consumption of certain food products can result in statistically significant changes in the composition of the gut microbiota in line with the prebiotic concept. The intestinal microbiota can be considered as a metabolically adaptable and rapidly renewable organ of the body. The qualitative and quantitative changes in the intake of specific food components (fatty acids, carbohydrates, micronutrients, prebiotics, probiotics), have not only consequences on the gut microbiota composition, but may modulate the expression of genes in host tissues such as the liver, adipose tissue, intestine, muscle.
Mice fed the high polyamine chow analyzed at 88 weeks of age, corresponding to the end of the study, demonstrated lower incidence of glomerulosclerosis and increased expression of senescence marker protein-30 in both kidney and liver compared to those fed the low polyamine chow. The growth and metabolism of microbial communities in the large intestine are determined by many factors, such as diet, environment and host physiological processes, as well as the anatomic structure of the digestive tract, disease, immunity, host genetics, drugs and ageing. An understanding of their full interactions with intestinal microbes and the host is needed to scientifically validate any health benefits they may afford. The literature provides new evidence that the increased prevalence of obesity and type 2 diabetes cannot be attributed solely to changes in the human genome, nutritional habits, or reduction of physical activity in our daily lives. The gut microbiota has profound effects on host gene expression in the enterohepatic system, including genes involved in immunity and metabolism.
The application of metagenomics to the gut microbial ecosystem revealed truly remarkable correlations between certain diseases and the gut microbiome.
Early-life events are instrumental in establishing the microbiota, the composition of which throughout life is influenced by various environmental and lifestyle pressures. Among the numerous purported health benefits attributed to probiotic bacteria, the (transient) modulation of the intestinal microflora of the host and the capacity to interact with the immune system directly or mediated by the autochthonous microflora, are basic mechanisms.
However, unbalances in its microbial community and activities are found to be implicated in disease initiation and progression, such as chronic inflammatory bowel diseases and colonic cancers. This in turn may drive or lessen the development of fat mass and metabolic disturbances associated with the gut barrier function and the systemic immunity. TLRs are also found on innate immune cells, such as dendritic cells and macrophages (Vinderola et al., 2005). Modifications in diet and host immune system activity, as well as physiological changes in the digestive tract affect microbiota composition in older people.
These include dietary supplements containing prebiotics, probiotics and a combination of both of these, synbiotics.
Recently, the genome sequences of nine strains representing four species of Bifidobacterium became available.
For example, the gut microbiota affects expression of secreted proteins in the gut, which modulate lipid metabolism in peripheral organs. They are supported by an increasing number of in vitro and in vivo experiments using conventional and molecular biologic methods. The more data are accumulating, the more it will be recognised that such changes in the microbiota’s composition, especially increase in bifidobacteria, can be regarded as a marker of intestinal health. Restoration of this balance by increasing bifidobacteria levels has demonstrated to reduce disease severity of patients and to improve well-being in healtly volunteers. The relevance of the prebiotic or probiotic approaches in the management of obesity in humans is supported by few intervention studies in humans up to now, but the experimental data obtained with those compounds help to elucidate novel potential molecular targets relating diet with gut microbes. The T-RFLP patterns in five of the six volunteers were changed in a similar fashion by LKM512 yogurt consumption, although these patterns were individually changed following consumption of placebo. They can be found in fermented products as meat, milk products, vegetables, beverages and bakery products. The elderly have fewer bifidobacteria and higher numbers of enterobacteria and clostridia than young adults.
A comparative genome analysis of these genomes reveals a likely efficient capacity to adapt to their habitats, with B. Scientists may take into consideration a key question: could we manipulate the microbiotic environment to treat or prevent obesity and type 2 diabetes? In addition, the gut microbiota is also a source of proinflammatory molecules that augment adipose inflammation and macrophage recruitment by signaling through the innate immune system. In addition to these, a limited number of randomized, well-controlled human intervention trials have been reported. The review is divided in chapters that cover the major areas of nutrition research where a prebiotic effect has tentatively been investigated for potential health benefits. New emerging evidence on the difference in the composition of the colonic microbiota between obese and lean volunteers has opened new areas for pre-, pro- and synbiotic research.
TLRs (Toll-like receptors) are integral parts of the innate immune system and are expressed by both macrophages and epithelial cells. The prebiotic effect has been shown to associate with modulation of biomarkers and activity(ies) of the immune system.
Nutrients with prebiotic properties allows, by changing the gut microbiota, to promote the endocrine function of the gut (increase in GLP-1, and GLP-2 producing cells), and to modulate the activation of the endocannabinoid system in the intestine and in the adipose tissue. We then analyzed inflammatory and intestinal conditions by measuring several markers using HPLC, ELISA, reverse transcription-quantitative PCR, and histological slices.
They are part of the microbiota on mucous membranes, such as the intestines, mouth, skin, urinary and genital organs of both humans and animals, and may have a beneficial influence on these ecosystems. Other known recognition receptors are nucleotide-binding oligomerization domain proteins, which recognize both gram-positive and gram-negative bacteria.
Activation of TLRs in macrophages dramatically impairs glucose homeostasis, whereas TLRs in the gut may alter the gut microbial composition that may have profound effects on host metabolism. All those effects contribute to lessen gut permeability (improved distribution of the tight junction proteins ZO-1 and Occludin), thereby decreasing endotoxemia, and systemic inflammation. LKM512 mice showed altered 16S rRNA gene expression of several predominant intestinal bacterial groups.
LAB that grow as the adventitious microflora of foods or that are added to foods as cultures are generally considered to be harmless or even an advantage for human health. This concomitantly improves stool quality (pH, SCFA, frequency and consistency), reduces the risk of gastroenteritis and infections, improves general well-being and reduces the incidence of allergic symptoms such as atopic eczema.
Changes in GLP-1 contribute to decrease food intake, fat mass, glycemia and insulin resistance. Since their discovery, LAB has been gained mush interest in various applications, as starter cultures in food and feed fermentations, pharmaceuticals, probiotics and as biological control agents. Increased epithelial barrier permeability is frequently associated with gastrointestinal disorders contributing to both disease onset and persistence (Lu and Walker 2001, Berkes 2003).
Changes in the gut microbiota composition are classically considered as one of the many factors involved in the pathogenesis of either inflammatory bowel disease or irritable bowel syndrome. Colonic mucosal function was also better in LKM512 mice, with increased mucus secretion and better maintenance of tight junctions.
In food industry, LAB are widely used as starters to achieve favorable changes in texture, aroma, flavor and acidity (Leory and De Vuyst, 2004). The gatekeeper of the paracellular pathway is the tight junction, which is an apically located cell-cell junction between epithelial cells. The similar changes in the intestinal microbiota of the elderly caused by consumption of the LKM512 yogurt were found to be influenced by the LKM512 strain itself, and not by the lactic acid bacteria in the yogurt. The tight junction permits the passage of small molecules, such as ions, while restricting the movement of large molecules, such as antigens and microorganisms, which can cause inflammation. An intriguing observation is the loss of much of this genome potential when strains are adapted to pure culture environments, as highlighted by the genomes of B. Prevention and alleviation of unspecific and irregular complaints of the gastrointestinal tracts in healthy people.
Promising beneficial effects have been demonstrated in some preliminary studies, including changes in gut microbiota composition (especially increase in bifidobacteria concentration). Du to their antimicrobial and antioxidant activities some LAB strains are used in food biopreservation.
This indicates that ingestion of specific probiotics may be an easy approach for improving intestinal health and increasing lifespan.
Origine and safety of probiotics An old dogma of probiotic selection has been that the probiotic strains should be of “human origin”.
Beneficial effects on microbial aberrancies, inflammation and other complaints in connection with: inflammatory diseases of the gastrointestinal tract, Helicobacter pylori infection or bacterial overgrowth. Many of the indications for probiotic activity have been obtained from effects observed in various clinical situations. One may argue that from evolutionary point of view, describing bacteria to be of human origin does not make much sense at all.
Some of these studies (including one human trial) have also reported that, in such conditions, gut microbiota composition was modified (especially due to increased concentration of bifidobacteria). The requirement for probiotics to be of human origin relates actually to the isolation of the strain rather than the “origin” itself.
Normalization of passing stool and stool consistency in subjects suffering from obstipation or an irritable colon. Dietary intake of particular food products with a prebiotic effect has been shown, especially in adolescents, but also tentatively in postmenopausal women, to increase Ca absorption as well as bone Ca accretion and bone mineral density.
Usually, the strains claimed to be “of human origin” have been isolated from faecal samples of healthy human subjects, and have therefore been considered to be “part of normal healthy human gut microbiota”.
Recent data, both from experimental models and from human studies, support the beneficial effects of particular food products with prebiotic properties on energy homaeostasis, satiety regulation and body weight gain.


Pathways that were downregulated by ageing were upregulated by LKM512 administration and vice versa.
Overview of probioticsThe most tried and tested manner in which the gut microbiota composition may be influenced is through the use of live microbial dietary additions, as probiotics.
In reality the recovery of a strain from a faecal sample does not necessarily mean that this strain is part of the normal microbiota of this individual, since microbes passing the GI tract transiently can also be recovered from the faecal samples (Forssten et al., 2011).
Together, with data in obese animals and patients, these studies support the hypothesis that gut microbiota composition (especially the number of bifidobacteria) may contribute to modulate metabolic processes associated with syndrome X, especially obesity and diabetes type 2.
In other words, LKM512 administration suppressed ageing-associated change in gene pathways. In practice it is impossible to know the actual origin of the probiotic strains, regardless of whether they have been isolated from faecal samples, fermented dairy products or any other source for that matter. It is plausible, even though not exclusive, that these effects are linked to the microbiota-induced changes and it is feasible to conclude that their mechanisms fit into the prebiotic effect.
Isolation of a strain from faeces of a healthy individual is also not a guarantee of the safety of the strain—such a sample will also always contain commensal microbes which can act as opportunistic pathogens, or even low levels of true pathogens, which are present in the individual at sub-clinical levels.
Prevention of respiratory tract infections (common cold, influenza) and other infectious diseases as well as treatment of urogenital infections. However, the role of such changes in these health benefits remains to be definitively proven.
However, at the beginning of this century probiotics were first put onto a scientific basis by the work of Metchnikoff (1908).
Insufficient or at most preliminary evidence exists with respect to cancer prevention, a so-called hypocholesterolemic effect, improvement of the mouth flora and caries prevention or prevention or therapy of ischemic heart diseases or amelioration of autoimmune diseases (e.g. He hypothesised that the normal gut microflora could exert adverse effects on the host and that consumption of ‘soured milks’ reversed this effect.
However, many species of the genera Lactobacillus, Leuconostoc, Pediococcus, Enterococcus, and Bifidobacterium were isolated frequently from various types of infective lesions. In other words, LKM512 administration suppressed ageing-associated change in gene pathways.” – “The anti-inflammatory effects of LKM512 administration were also revealed by a DNA microarray.
Today, only bifidogenic, non-digestible oligosaccharides (particularly inulin, its hydrolysis product oligofructose, and (trans)galactooligosaccharides), fulfill all the criteria for prebiotic classification. Expression levels of genes in the TNF-NF?B, IL-1, IL-2, and IL-6 pathways were higher in the control group than in LKM512 and younger mice; additionally, gene expression levels in LKM512 mice were similar to those in younger mice (Fig.
The origin of the first use can be traced back to Kollath (1953), who used it to describe the restoration of the health of malnourished patients by different organic and inorganic supplements. They are dietary fibers with a well-established positive impact on the intestinal microflora. Later, Vergin (1954) proposed that the microbial imbalance in the body caused by antibiotic treatment could have been restored by a probiotic rich diet; a suggestion cited by many as the first reference to probiotics as they are defined nowadays. Other health effects of prebiotics (prevention of diarrhoea or obstipation, modulation of the metabolism of the intestinal flora, cancer prevention, positive effects on lipid metabolism, stimulation of mineral adsorption and immunomodulatory properties) are indirect, i.e. Similarly, Kolb recognized detrimental effects of antibiotic therapy and proposed the prevention by probiotics (Vasiljevic and Shah, 2008) Later on, Lilly and Stillwell (1965) defined probiotics as “…microorganisms promoting the growth of other microorganisms”. The idea of health-promoting effects of LAB is by no means new, as Metchnikoff proposed that lactobacilli may fight against intestinal putrefaction and contribute to long life.
Although minor side effects of the use of probiotics have been reported, infections with probiotic bacteria occur and invariably only in immunocompromised patients or those with intestinal bleeding (Leroy et al., 2008). Other definitions advanced through the years have been restrictive by specification of mechanisms, site of action, delivery format, method, or host.
An issue of concern regarding the use of probiotics is the presence of chromosomal, transposon, or plasmid-located antibiotic resistance genes amongst the probiotic microorganisms. At this moment, insufficient information is available on situations in which these genetic elements could be mobilised, and it is not known if situations could arise where this would become a clinical problem (Leroy et al., 2008). The mechanism of action of probiotics (e.g, having an impact on the intestinal microbiota or enhancing immune function) was dropped from the definition to encompass health effects due to novel mechanisms and to allow application of the term before the mechanism is confirmed. Furthermore, certain mechanisms of action (such as delivery of certain enzymes to the intestine) may not require live cells.
In vitro safety screenings of probiotics may include, among others, antibiotic resistance assays, screenings for virulence factors, resistance to host defence mechanisms and induction of haemolysis. In relation to food, probiotics are considered as “viable preparations in foods or dietary supplements to improve the health of humans and animals”.
According to these definitions, an impressive number of microbial species are considered as probiotics. ConclusionThe individual diversity of the intestinal microflora underscores the difficulty of identifying the entire human microbiota and poses barriers to this ?eld of research. Selection of probioticsMany in vitro tests are performed when screening for potential probiotic strains. The first step in the selection of a probiotic LAB strain is the determination of its taxonomic classification, which may give an indication of the origin, habitat and physiology of the strain. It is also apparent that even a single strain of probiotic may exert its actions via multiple, concomitant pathways. All these characteristics have important consequences on the selection of the novel strains (Morelli, 2007).
Probiotics have long been used as an alternative to traditional medicine with the goal of maintaining enteric homeostasis and preventing disease. This conclusion was brought forward due to uncertainty of the origin of the human intestinal microflora since the infants are borne with virtually sterile intestine. Clinical trials have shown that probiotic treatment can reduce the risk of some diseases, especially antibiotic-associated diarrhea, but conclusive evidence is impeded owing to the wide range of doses and strains of bacteria used. However, the panel also underlined a need for improvement of in vitro tests to predict the performance of probiotics in humans. While many probiotics meet criteria such as acid and bile resistance and survival during gastrointestinal transit, an ideal probiotic strain remains to be identified for any given indication. Many studies, as discussed above, have shown that probiotics increase barrier function in terms of increased mucus, antimicrobial peptides, and sIgA production, competitive adherence for pathogens, and increased TJ integrity of epithelial cells.
Furthermore, it seems unlikely that a single probiotic will be equally suited to all indications; selection of strains for disease-specific indications will be required (Shanahan, 2003).
Current investigation into the mechanism of action of speci?c probiotics has focused on probiotic-induced changes in the innate immune functions involvingTLRs and its downstream systems Like NF-?B, and other pathways (Yoon and Sun, 2011). Although the immunomodulatory effects of probiotics have been demonstrated in experimental animal models of allergy, autoimmunity, and IBD, information from clinical trials in humans is scarce. The ability to adhere to the intestinal mucosa is one of the more important selection criteria for probiotics because adhesion to the intestinal mucosa is considered to be a prerequisite for colonization (Tuomola et al., 2001). The table below (Table 2) indicates key creteria for sellecting probiotic candidat for commercial application, and figure 1 presents major and cardinal steps for sellecting probiotic candidats.It is of high importance that the probiotic strain can survive the location where it is presumed to be active. Therefore, more research, especially in the form of well-designed clinical trials, is needed to evaluate the ef?cacy and safety of probiotics (Ezendam and Van Loveren, 2008).
For a longer and perhaps higher activity, it is necessary that the strain can proliferate and colonise at this specific location.
Probably only host-specific microbial strains are able to compete with the indigenous microflora and to colonise the niches. Besides, the probiotic strain must be tolerated by the immune system and not provoke the formation of antibodies against the probiotic strain. On the other hand, the probiotic strain can act as an adjuvant and stimulate the immune system against pathogenic microorganisms.
Basic initial characterization of strain identity and taxonomy should be conducted, followed by evaluation with validated assays both in studies of animal models and in controlled studies in the target host. In vitro assays are frequently conducted that have not been proved to be predictive of in vivo function.
Technological robustness must also be determined, such as the strain’s ability to be grown to high numbers, concentrated, stabilized, and incorporated into a ?nal product with good sensory properties, if applicable, and to be stable, both physiologically and genetically, through the end of the shelf life of the product and at the active site in the host. Assessment of stability can also be a challenge, since factors such as chain length and injury may challenge the typical assessment of colony-forming units, as well as in vivo function (Sanders, 2008). Dose levels of probiotics should be based on levels found to be ef?cacious in human studies. Furthermore, the impact of product format on Figure 1.Scheme of the Guidelines for the Evaluation of Probiotics for Food Use.
The common quality-control parameter of colony-forming units per gram may not be the only parameter indicative of the ef?cacy of the ?nal product. Other factors, such as probiotic growth during product manufacture, coating, preservation technology, metabolic state of the probiotic, and the presence of other functional ingredients in the ?nal product, may play a role in the effectiveness of a product. Potential mechanisms of action of probioticsA wide variety of potential beneficial health effects have been attributed to probiotics (Table 3). Claimed effects range from the alleviation of constipation to the prevention of major life-threatening diseases such as inflammatory bowel disease, cancer, and cardiovascular incidents.
Some of these claims, such as the effects of probiotics on the shortening of intestinal transit time or the relief from lactose maldigestion, are considered well-established, while others, such as cancer prevention or the effect on blood cholesterol levels, need further scientific backup (Leroy et al., 2008). The mechanisms of action may vary from one probiotic strain to another and are, in most cases, probably a combination of activities, thus making the investigation of the responsible mechanisms a very difficult and complex task. In general, three levels of action can be distinguished: probiotics can influence human Probiotic organisms can provide a beneficial effect on intestinal epithelial cells in numerous ways. Gut microbiotaThe human gastrointestinal tract is inhabited by a complex and dynamic population of around 500-1000 of different microbial species which remain in a complex equilibrium.
It has been estimated that bacteria account for 35–50% of the volume content of the human colon. These include Bacteroides, Lactobacillus, Clostridium, Fusobacterium, Bifidobacterium, Eubacterium, Peptococcus, Peptostreptococcus, Escherichia and Veillonella. The bacterial strains with identified beneficial properties include mainly Bifidobacterium and Lactobacillus species. The dominant microbial composition of the intestine have been shown to be stable over time during adulthood, and the microbial patterns are unique for each individual. However, there are numerous external factors that have potential to influence the microbial composition in the gut as host genetics, birth delivery mode, diet, age, antibiotic treatments and also, other microorganisms as probiotics. The intestine is one of the main surfaces of contact with exogenous agents (viruses, bacteria, allergens) in the human body. It has a primary role in the host defense against external aggressions by means of the intestinal mucosa, the local immune system, and the interactions with the intestinal microbiota (resident and in transitbacteria). Gut microbiota influences human health through an impact on the gut defense barrier, immune function, nutrient utilization and potentially by direct signaling with the gastrointestinal epithelium (Collado et al., 2009).
In healthy adults, 80% of phylotypes belong to four major phylogenetic groups, which are the Clostiridium leptum, Clostridium coccoides, Bacteroides and Bifidobacteria groups.
Also, studies have found that mucosal microbiota is stable along the distal gastrointestinal tract from ileum to rectum, but mucosa-associated microbiota is different from fecal microbiota. The number of bacterial cells present in the mammalian gut shows a continuum that goes from 101 to 103 bacteria per gram of contents in the stomach and duodenum, progressing to 104 to 107 bacteria per gram in the jejunum and ileum and culminating in 1011 to 1012 cells per gram in the colon (Figure 3a). In addition to the longitudinal heterogeneity displayed by the intestinal microbiota, there is also a great deal of latitudinal variation in the microbiota composition (Figure 3b).
The intestinal epithelium is separated from the lumen by a thick and physicochemically complex mucus layer. The microbiota present in the intestinal lumen differs significantly from the microbiota attached and embedded in this mucus layer as well as the microbiota present in the immediate a: variations in microbial numbers and composition across the length of the gastrointestinal tract. For instance, Bacteroides, Bifidobacterium, Streptococcus, members of Enterobacteriacea, Enterococcus, Clostridium, Lactobacillus, and Ruminococcus were all found in feces, whereas only Clostridium, Lactobacillus, and Enterococcus were detected in the mucus layer and epithelial crypts of the small intestine (Sekirov et al., 2010).
Upon passage through the birth canal, infants are exposed to a complex microbial population. After the initial establishment of the intestinal microbiota and during the first year of life, the microbial composition of the mammalian intestine is relatively simple and varies widely between different individuals and also with time.
Survival and antagonism effects of probiotics in the gutThe intestinal epithelium is the largest mucosal surface in the human body, provides an interface between the external environment and the host. The gut epithelium is constantly exposed to foreign microbes and antigens derived from digested foods.
Thus, the gut epithelium acts as a physical barrier against microbial invaders and is equipped with various elements of the innate defense system. In the gut, two key elements govern the interplay between environmental triggers and the host: intestinal permeability and intestinal mucosal defense. Resident bacteria can interact with pathogenic microorganisms and external antigens to protect the gut using various strategies.According to the generally accepted de?nition of a probiotic, the probiotic microorganism should be viable at the time of ingestion to confer a health bene?t. Although not explicitly stated, this de?nition implies that a probiotic should survive GI tract passage and, colonize the host epithelium. A variety of traits are believed to be relevant for surviving GI tract passage, the most important of which is tolerance both to the highly acidic conditions present in the stomach and to concentrations of bile salts found in the small intestine. These properties have consequently become important selection criteria for new probiotic functionality. One of the mechanisms by which the gut ?ora resists colonization by pathogenic bacteria is by the production of a physiologically restrictive environment, with respect to pH, redox potential, and hydrogen sul?de production. Probiotic bacteria decrease the luminal pH, as has been demonstrated in patients with ulcerative colitis (UC) following ingestion of the probiotic preparation VSL#3. Several bacteriocins produced by different species from the genus Lactobacillus have been described. The inhibitory activity of these bacteriocins varies; some inhibit taxonomically related Gram-positive bacteria, and some are active against a much wider range of Gram-positive and Gram-negative bacteria as well as yeasts and molds. Lacticin 3147, a broad-spectrum bacteriocin produced by Lactococcus lactis, inhibits a range of genetically distinct Clostridium dif?cile isolates from healthy subjects and patients with IBD.
A further example is the antimicrobial effect of Lactobacillus species on Helicobacter pylori infection of gastric mucosa, achieved by the release of bacteriocins and the ability to decrease adherence of this pathogen to epithelial cells (Gotteland et al., 2006). The pretreatment of intestinal (T84) cells with lactic acid-producing bacteria reduced the ability of pathogenic E.
Adhesion and invasion of an intestinal epithelial cell line (Intestine 407) by adherent invasive E.
Probiotics and the mucous layerMost mucosal surfaces are covered by a hydrated gel formed by mucins.
Mucins are secreted by specialized epithelial cells, such as gastric foveolar mucous cells and intestinal goblet cells, Goblet cells are found along the entire length of the intestinal tract, as well as other mucosal surfaces. Of the 18 mucin-type glycoproteins expressed by humans, MUC2 is the predominant glycoprotein found in the small and large bowel mucus. The NH2- and COOH-termini are not glycosylated to the same extent, but are rich in cysteine residues that form intra- and inter-molecular disul?de bonds. These glycan groups confer proteolytic resistance and hydrophilicity to the mucins, whereas the disul?de linkages form a matrix of glycoproteins that is the backbone of the mucous layer (Ohland and MacNaughton, 2010). Although small molecules pass through the heavily glycosylated mucus layer with relative ease, bulk fluid flow is limited and thereby contributes to the development of an unstirred layer of fluid at the epithelial cell surface. As the unstirred layer is protected from convective mixing forces, the diffusion of ions and small solutes is slowed (Turner, 2009). This gel layer provides protection by shielding the epithelium from potentially harmful antigens and molecules including bacteria from directly contacting the epithelial cell layer, while acting as a lubricant for intestinal motility.
Mucins can also bind the epithelial cell surface carbohydrates and form the bottom layer, which is ?rmly attached to the mucosa, whereas the upper layer is loosely adherent.
The mucus is the ?rst barrier that intestinal bacteria meet, and pathogens must penetrate it to reach the epithelial cells during infection (Ohland and MacNaughton, 2010).Probiotics may promote mucus secretion as one mechanism to improve barrier function and exclusion of pathogens. In support of this concept, probiotics have been shown to increase mucin expression in vitro, contributing to barrier function and exclusion of pathogens. Several studies showed that increased mucin expression in the human intestinal cell lines Caco-2 (MUC2) and HT29 (MUC2 and 3), thus blocking pathogenic E.
However, healthy rats did not display increased colonic TFF3 expression after stimulation by VSL#3 probiotics (Caballero-Franco et al., 2007). Furthermore, mice treated with 1% dextran sodium sulfate (DSS) to induce chronic colitis did not exhibit increased TFF3 expression or wound healing when subsequently treated with VSL#3.
This observation indicates that probiotics do not enhance barrier function by up-regulation of TFF3, nor are they effective at healing established in?ammation. Therefore, use of current probiotics is likely to be effective only in preventing in?ammation as shown by studies in animal models (Ohland and MacNaughton, 2010).5. Interaction of probiotic bacteria with gut epitheliumThe composition of the commensal gut microbiota is probably influenced by the combination of food practices and other factors like the geographical localization, various levels of hygiene or various climates.
The establishment of a normal microbiota provides the most substantial antigenic challenge to the immune system, thus helping the gut associated lymphoid tissus (GALT) maturation. The intestinal microbiota contributes to the anti-inflammatory character of the intestinal immune system. Several immunoregulatory mechanisms, including regulatory cells, cytokines, apoptosis among others, participate in the control of immune responses by preventing the pathological processes associated with excessive reactivity. An interesting premise for probiotic physiological action is their capacity to modulate the immune system.
Consequently, many studies have focused on the effects of probiotics on diverse aspects of the immune response. Following consumption of probiotic products, the interaction of these bacteria with intestinal enterocytes initiates a host response, since intestinal cells produce various immunomodulatory molecules when stimulated by bacteria (Delcenseri et al., 2009). Furthermore, The indigenous microbiota is a natural resistance factor against potential pathogenic microorganisms and provides colonization resistance, also known as gut barrier, by controlling the growth of opportunistic microorganisms. It has been suggested that commensal bacteria protect their host against microbial pathogens by interfering with their adhesion and toxic effects (Myllyluoma, 2007).A fraction of ingested probiotics are able to interact with intestinal epithelial cells (IECs) and dendritic cells (DCs), depending on the presence of a dynamic mucus layer. Probiotics can occasionally encounter DCs through two routes: DCs residing in the lamina propria sample luminal bacterial antigens by passing their dendrites between IECs into the gut lumen, and DCs can also interact directly with bacteria that have gained access to the dome region of the gut-associated lymphoid tissue (GALT) through specialized epithelial cells, termed microfold or M cells. The interaction of the host cells with microorganism-associated molecular patterns (MAMPs) that are present on the surface macromolecules of probiotic bacteria will induce a certain molecular response. The host pattern recognition receptors (PRRs) that can perceive probiotic signals include Toll-like receptors (TLRs) and the C type lectin DC-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN). Some molecular responses of IECs depend on the subtype of cell, for example, Paneth cells produce defensins and goblet cells produce mucus. Important responses of DCs against probiotics include the production of cytokines, major histocompatibility complex molecules for antigen presentation, and co-stimulatory molecules that polarize T cells into T helper or CD4+CD25+ regulatory T cells in the mesenteric lymph nodes (MLNs) or subepithelial dome of the GALT. Host interactions of probiotic bacterial surface molecules: comparison with commensals and pathogens.



Antibiotics for cats urinary tract infection
Where to buy acidophilus pills in canada
Probiotics to buy over the counter glasses
Category: Best Probiotic Pills


Comments to “Effect of probiotic bifidobacterium”

  1. JESSICA:
    That it will convince you to purchase it again.
  2. crazy_girl:
    From the food we eat, and consist mainly of proteins so there is the thinking that.
  3. Prodigy:
    You'll need to continuously probiotic supplements out over.