The Role of the Intestinal Microbiota in Health and Disease - Coursework Example

THE ROLE OF THE INTESTINAL MICROBIOTA IN HEALTH AND DISEASE Academic Degree and al Affiliation of Department and Institution Correspondent Author for the Document Abstract The aim of conducting this study is to establish the complex roles of intestinal microbiota in health and disease. It begins by introducing the concept, what intestinal microbiota means, its location and evolution in human body. The roles are identified as intestinal mucosa development, metabolism, acquisition of nutrients, production of micronutrients, for protection in the immune system, development of GALT and cells, and in structures and GIT function. Finally, it addresses microbial influenced disease. Keywords: Gut or Intestinal Microbiota, Microbiome, Nutrients, Metabolism, Mucosa, Colon, Bacteria, Diet, Infant Diseases Table of Contents Table of Contents 3 3.Jabr, F. The Food Fight in Your Gut: Why Bacteria Will Change the Way You Think about Calories [Internet]. [Place Unknown]: Scientific American; 2012. Available from http://blogs.scientificamerican.com/brainwaves/2012/09/12/the-food-fight-in-your-guts-why-bacteria-will-change-the-way-you-think-about-calories/ 12 4.Tamime, A.Y, editor. Probiotic dairy products. Oxford: Blackwell Publishing Ltd. 2005. 12 5.Mullin, G. Integrative Weight Management: A Guide for Clinicians. New York: Springer Science and Business. 2014. 12 8.Upton, J. The Link Between Carbs, Gut Microbes, and Colon Cancer [Internet]. [Place Unknown]: Pacific standard; 2014. Available from http://www.psmag.com/health-and-behavior/links-carbs-gut-microbes-colon-cancer-86437 13 9.Study reveals that people may inherit ‘gut’ bacteria that cause Crohn’s disease and ulcerative colitis. [Internet]. [Place Unknown]: University of Minnesota; 2014[Updated on 2015 February 6]. Available from http://discover.umn.edu/news/science-technology/people-may-inherit-gut-bacteria-cause-crohns-disease-and-ulcerative-colitis 13 Introduction A human body is a residence of hundreds of species of microorganisms. These organisms are located in different parts like the mouth, intestines, skin surface and deep layers among others. Intestinal or gut microbiota as the name suggests is an ensemble of microorganisms in the gastrointestinal tract, specifically at the intestines, which are exposed to the external environment. The microorganisms are a constituent of bacteria, unicellular eukaryotes and viruses among others, least to mention their species. They coexist harmoniously within the hosts body, feeding on the nutrients and capable of performing specific physiological and biological functions to support the body systems. Sekirov et al point that the most microbial colonized part of the human body is “the gastrointestinal track (GIT), where the colon alone is estimated to contain over 70% of all the microbes in the human body.” (1, p 860) Right from birth, an infant’s system comes into contact with the mother’s microbiota and later through breast feeding which is initiated by galacto-oligosaccharides in the milk. During pregnancy, the mother’s body is in active creation of the diverse gut microbiota, which later colonizes the infant’s body. Despite the number of species, only two “bacteria phyla, Firmicutes and the Bacteroidetes” dominate the gut microbiota. (1, p 860) Inclusive of the ingested materials, surrounding environment and the host genetics constitute the non homogenous bacterial that succeed into the human gut and intestines. Concerning the body functions, microbiota plays important roles in the body’s immune system, nutrition, metabolism and even human physiology among other s in the general human health. The role of gut/intestinal microbiota Nutrient acquisition Intestinal microbiota directly influences the human nutritional status through degradation of the indigestible food materials ingested in the body. As the grinded food moves down digestive track, the intestinal cells and the bacterial organisms scramble for absorption of rich nutrients passing across the intestines. Considering that the microorganisms outnumber the intestinal cells, their nutrient harvests are greater and are actively competing with the cells. The net effect of this could be under nutrition, insulin resistance and increase of body fat content that affects body weight. One, the body depends on large intake of the nutrients for the development of the microbiome, while the increase in the number of later could deprive the body its nutrients materials (e.g fat and vitamins). Recent research by Harris et al demonstrated that reduction in cecal microbiota among obese mice resulted in high level decline of glucose and contributed to the inception of insulin resistance. (2) Metabolism role The intestinal microbiota acts a metabolic organ which facilitates in the extraction of calories for energy intake. Food substances consumed in the body contain high glucose and fats among others that are rich sources of energy. Intestinal cells are known to aid in metabolism process, but in collaboration with certain bacteria improve the substances breakdown for increased energy production. Instead of letting the indigestible ligo-saccharides be passed down, the intestinal microbiota break them down to extract the extra calories. Jabr claims that it’s involved in breakdown of dietary fibre into short chain fatty acids (SCFA), and dismantling of complex food molecules into digestible substances. (3) The absorbed calories are not only to benefit the microorganisms, but large proportions of dietary lipids are deposited in the host’s adipose tissue. The energy uptake and storage of calories are critical for the human body to keep it functioning even at times of under nutrition. In effect, alteration to microbiota and its involvement in body metabolism is linked to human’s Obesity and energy homeostasis. With increased level of bacterial lipopolysaccharidefrom the microbiota, individuals used to high fat diet risk gaining more weight as result of the intestinal inflammation. (2) Through the microbial enzymes metabolism of glucose and cholesterol materials are as a result of bile acid biotransformation. Similarly, improved metabolism of fermentative bacteria would trigger high energy production and food intake to create energy imbalance within the body. Production of micronutrient components A human body is incapable of synthesizing vitamins. It hence relies on the food ingested as well as production by the intestinal microbiota. Apparently, the bacteria in the intestines function as vitamins production plants for the human body. It occurs that the mirobiome systhesize vitamins for their use; however, the excess production which are intended for excretion from the organisms become the source of vitamins for the host. Tamime associates the production of vitamin K and B to gut nicrobiota, (4) which aid in protein synthesis vital absorption of soluble salts and for coagulation and a broad range of metabolism processes. In precise the B12 category of B-group vitamins and K highly secreted by the gut microbiome are rare. For example, bacteroides aid in production of vitamin K2 bifidobacterium in synthesis of the B- complex and K. Besides them, Mullin claims that “water soluble vitamins (folate, biotin, pantothenic acid, thiamine and riboflavin) available in diets are also produced in the gut microbiota.” (5, p79) The production of all these vitamins after their synthesization in the gut occur at different rates Development of intestinal mucosa The development of innate immune system among infants is vital for protection against infections. To foster normal development of normal gut immune system among infants, commensal microbiota has to influence and stimulate the maturity of the intestinal mucosa. Purchiaroni argues that the maturity is reflected by the infant’s mucosa immune system capability to “distinguish the digestive functions in the body, harmless antigens from pathogenic microbial and recognition of conserved characteristic molecules of the microorganism.” (6, p324) Gut epithelium plays an integral part in response to foreign pathogens/foreign antigens. When the epithelium surface comes into contact with the intestinal bacteria, eukaryotic and prokaryotic cells engage in a communication exchange via the signals transduction channels. Protection or barrier effect The established mucosal immune system generates over halve of the body’ immunological ly active cells, and by the microbiota forming a percentage of the mucosal surfaces provides its host with intestinal barrier function. Attached commensal bacteria would act to activate the efferent component to instigate mucosal immune defences when their receptors plug into the microvillus membrane. Within the mucosal lymphoid tissues the body can actively get to initiate adaptive immune responses, which is controlled through regulated T lymphocytes. As earlier on stated, microbiota serve to exclude the pathogenic organisms by looking into their features. It will investigate the role of the pathogen/antigen to attach to a particular site, what the foreign organism feeds on in terms of nutrients and the substances it produces before hindering it from accessing the host. In the case where pathogenic bacteria are detected in the body, microbiota takes the responsibility to stimulate the host so as to release antimicrobial compounds that destroy the organs. Development of cells and GALT Intestinal bacteria play a role in tissue and cell development necessary for the human organs and functioning. Various researches indicate that the development Gut associated lymphoid tissues (GALT) are in response to stimulation by intestinal microbiota (7, p1119). The butyrate producing bacteria in the intestines has been linked to cell proliferation in both the small intestines and colon. Butyrate bacteria result from fermentation in the colon of the indigestible that passed down from the small intestines. These cell proliferation supports diverse people especially those recovering from the surgical operation and infections where they lose tens of hundred of cells. Butyrate initiates cell growth and serve as differentiating agents for cells like the T cells. From a previous experiment Rhee et al established that involving bacterial induced cecal contents, “germ free appendix rabbits demonstrated Ki67+ B cell follicles that expressed low levels of IgM, which is achar-acteristic of proliferating B cells.” (7, p1119) By comparing the induced bacterial, it was evident that with combinations of B fragilis with S epidermidis or B subtilis, caused GALT development. Structure and function of the GIT By the time of birth, infant’s GIT are structurally and functionally immature. The physiological development of the child’s gut microbiota is influenced by both vaginal and milk microorganisms other than those on the skin. Hence, the influence of the microbial community on the host’s physiology and development becomes an immediate process. Developing gut microbiota already introduced will influence the infant’s epithelium differentiation, and after the weaning period they become firmly established in the life of the child. The multitude of bacteria in small intestines and colons and in line with digestion purpose may have additional role as the contemplated promotion of intestinal angiogenesis. Though studies are currently underway, existent results imply that intestinal microbiota facilitate the development of blood vessels. Exposure to bacterial in the test objects showed that the mammals began developing intestinal microvasculature. Rerikov et al also states that specific microbial members “contrib-ute to the maintenance of intestinal epithelium barrier integrity through maintenance of cell-to-cell junctions and promotion of epithelial repair following injury.” (1, p867) Below is an illustration summary of commensal bacteria by Heitch. (10, p9) Generalized roles of commensal bacteria in human body Influence on diseases Predisposition to cancer There exists a link between carbohydrates intake and gut microbes in the colons, which influence cancer diseases. Gut microbes in the colon have the ability to interact with the diet and stimulate excessive mutation. Carbohydrates are broken down by the gut bacteria into metabolites which speed up cells division along the colon to form polyps that can result in abnormal cancerous growths. (8) Apparently, reduction in intestinal microbiome reacted to hinder development of malignant lumps that developed along the intestinal walls. Autoinflammatory disease Inflammation does not necessarily imply abnormality. It is a vital process of the immune system in response to body infection/injury. However, the ingested microbes in foods like dairy and meat and other bacterial residing in the gastrointestinal track are capable of triggering inflammatory of the bowels. For example, intestinal bacterial can cause intestinal infection, which causes some people to develop irritable bowel syndrome (IBS). A recent study by a collective team of researches revealed that inherited intestinal bacteria could not only affect an individual’s entire life, but could also serve as the source of ulcerative colitis and Crohn’s diseases in their bodies. (9) Due to such inflammations initiated in response to infections like HIV, the patient may suffer from persistence inflammations and fast attacks by chronic diseases than non HIV patients. Liver disease Inflammations resulting for endotoxemia and high level intestinal permeability influenced by changes in gut micribiome can potentially cause liver cirrhosis, portal hypertension and even Minimal hepatic encephalopathy (MHE) when neurotoxic materials mount up in the bloodstream. Obesity Gut microbiotais involved in provision of additional energy in the body during dietary conversion. It also contributes to increased intestinal permeability to cause increased lipopolisaccharides. This is associated with weight gain and an effect of insulin resistance. Low grade inflammation also results from metabolic endotoxomia, which all are basic traits for encroaching obesity. Increased levels of intestinal bacteria can trigger low glucose tolerance and greater adiposity through increment of glucose or monosaccharide level in the serum. Reference List 1. Sekirov, I., Russeel, L. N., Antunes, C.M., Finlay, B.B. Gut Microbiota in Health and Disease. Physiol Rev. 2010; 90: 859 –904. 2. Harris, K., Kassi, A., Major, G., and Chou, C.J. Is the Gut Microbiota a New Factor Contributing to Obesity and Its Metabolic Disorders? J of Obesity 2012; 1-14. http://www.hindawi.com/journals/jobe/2012/879151/ 3. Jabr, F. The Food Fight in Your Gut: Why Bacteria Will Change the Way You Think about Calories [Internet]. [Place Unknown]: Scientific American; 2012. Available from http://blogs.scientificamerican.com/brainwaves/2012/09/12/the-food-fight-in-your-guts-why-bacteria-will-change-the-way-you-think-about-calories/ 4. Tamime, A.Y, editor. Probiotic dairy products. Oxford: Blackwell Publishing Ltd. 2005. 5. Mullin, G. Integrative Weight Management: A Guide for Clinicians. New York: Springer Science and Business. 2014. 6. Purchiaroni, F., Tortora, A., Gabrielli, M., Bertucci, F., Gigante, G., Ianiro, G., Ojetti, V., Scarpellini, E., Gasbarrini, A. The role of intestinal microbiota and the immune system. European Review of medical and pharmacological sciences. 2013; 17: 323-333.http://www.europeanreview.org/wp/wp-content/uploads/323-333.pdf 7. Rhee, K., Sethupathi, P., Driks, A., Lanning, D.K., and. Knight K.L. Preimmune Antibody Repertoire of Gut-Associated Lymphoid Tissues and Role of Commensal Bacteria in Development. J of Immunology. 2004; 172:1118-1124 8. Upton, J. The Link Between Carbs, Gut Microbes, and Colon Cancer [Internet]. [Place Unknown]: Pacific standard; 2014. Available from http://www.psmag.com/health-and-behavior/links-carbs-gut-microbes-colon-cancer-86437 9. Study reveals that people may inherit ‘gut’ bacteria that cause Crohn’s disease and ulcerative colitis. [Internet]. [Place Unknown]: University of Minnesota; 2014[Updated on 2015 February 6]. Available from http://discover.umn.edu/news/science-technology/people-may-inherit-gut-bacteria-cause-crohns-disease-and-ulcerative-colitis 10. Heich, G. The power of the microbiome. Commensal bacteria. [image on the internet]. [date unknown].Available from http://www.stritch.luc.edu/cme/sites/default/files/cme/3_26_13_hecht.pdf Read More