Intestine Probiotics: Common application and use in the intestines

By Freya Feng

Grade 11

Introduction

Have you ever heard the word biological broom? That is the description for probiotics. Why is it called a broom? Well, you will know the reason after you read this article. In the intestinal tract of humans and animals, there are complex relationships such as habitat, partial growth, competition, or phagocytosis. Through these relationships, probiotics improve the balance of the host's intestinal microbial flora, play a role in promoting beneficial food metabolism, improving and treating metabolic diseases. Beneficial bacteria or fungi in humans and animals mainly include Clostridium butyricum, lactic acid bacteria, bifidobacteria, Lactobacillus acidophilus, actinomycetes, and yeasts.

Probiotics have been defined by the WHO as "live microorganisms" that are beneficial to the health of the host. By colonizing the intestinal tract, they can effectively improve the intestinal microenvironment, reduce the pH of the intestine, prevent the translocation of intestinal bacteria to prevent and treat intestinal diseases. This article is going to briefly introduce the beneficial effects of intestinal probiotics.

Positive Effects of Probiotics on the Intestine

Enhance intestinal epithelial cell barrier function

(Figure 1.The mechanics of probiotics in the intestine)

Probiotics increase mucus production and maintain the integrity of the barrier. It can also increase the amount of defensins secreted by intestinal epithelial cells, which can play a role in acute infectious enteritis. Probiotics can block the denaturation of tight-junction proteins and increase the electrical impedance of tight junctions through the protein kinase C pathway and the mitogen-activated protein kinase pathway. Probiotics increase intestinal epithelial barrier integrity by employing a mouse model of stress-induced intestinal barrier dysfunction. Figure 1 showed an overview of the mechanics of probiotics in the intestine.

Immunomodulatory effect

The intestine is the largest immune organ. The area of the intestinal mucosa is about the size of a tennis court, and its structure and function constitute a powerful mucosal immune system. The intestinal mucosal immune system includes gut-associated lymphoid tissue, lymphocytes and molecules.

In a person's life, more than 95% of infectious diseases are directly or indirectly related to the intestine.

- The effect of probiotics on non-specific immunity

Nonspecific immunity, also known as innate immunity, involves many immune cells, including macrophages and NK cells. Macrophages are important factors that cause non-specific immunity in the body, and can secrete cytokines to promote the proliferation and differentiation of immune cells or enhance immune responses. According to experiments, some probiotics can enhance the immune ability of immune cells and strengthen the immune ability of the human body.

- The effect of probiotics on specific immunity

Specific immunity, also known as acquired immunity, includes cellular immunity and humoral immunity. Cellular immunity is an immune response with T lymphocytes as the core. When T cells come into contact with certain pathogens, with the participation of macrophages, T cells differentiate and proliferate into immune T cells. Lactic acid bacteria have a stimulating effect on intestinal lymphocytes, can produce interferon, enhance the phagocytosis of mononuclear phagocytes, and kill enteroviruses and other bacteria. Humoral immunity is an immune response in which specific antibodies play a major role. The body's immune system can synthesize and secrete immunoglobulins, and these antibodies can recognize and specifically bind to antigens, mediate the activity of immune cells, and enhance the phagocytic function of phagocytes. Some animal experiments have shown that probiotics can improve the function of the intestinal mucosal barrier, promote the production of specific and non-specific antibodies, and enhance the function of the immune system. As figure 2 showed, the probiotics produce bioactive compounds by using the substrates from diet, and the bioactive compounds can affect the immune system.

The regulation of the enteric nervous system

Regulating the enteric nervous system is mainly to increase the threshold value of neuronal action potential and corresponding receptors. Lactobacillus can reduce the sensitivity of dorsal root ganglion neurons of the spinal cord caused by colorectal expansion stimulation and can also relieve certain visceral pain. Experiments by Rousseaux et al. have also shown that probiotics can significantly improve abdominal discomfort caused by some intestinal diseases by activating corresponding receptors in the intestine.

Furthermore, the result of medical experiment showed, “treatments with antibiotics or probiotics such as L. paracasei DSM 13434 and L. plantarum DSM 15312 resulted in alleviation of EAE clinical symptoms and inflammation by suppression of IL-17 production and accumulation of regulatory T cells in secondary lymphoid organs. These observations suggested that probiotics could result in changes in the composition of the intestinal microbiome and favorable outcomes in patients suffering from autoimmune diseases.”

Intestinal nutrition health regulation function

Regulation of gut microbiota on host nutrient metabolism gut microbes take nutrients from the host gut for self-enjoyed tissue renewal and excrete unavailable substances. This form invisibly participates in the host's digestion, absorption and metabolism of nutrients. Most studies have shown that the way for intestinal flora to obtain nutrients is that after the food is degraded in the stomach and small intestine, it enters the gastrointestinal wall through the apical membrane transport carrier of the gastrointestinal epithelial cells, then transfers out through the basement membrane transport carrier, and enter the blood circulation for use by the intestines and other tissues.

With the deepening of research on the relationship between host nutrient metabolism and intestinal flora, especially after the study of the genome of the host and intestinal flora, researchers have found that the intestinal flora mainly participates in the sugar, protein and fats of the host, Affects the host's digestion, metabolism and absorption of nutrients, thereby regulating the host's nutritional level, health status, immunity and enteric brain nervous system.

Conclusion

“Probiotics have been proposed as preventive and therapeutic measures, in order to restore the healthy composition and function of the gut microbiome.” It is powerful and has multiple important functions in our body. The way to gain more probiotics is to eat some yogurt, bread or even kimchi and many other things you like. Did you gain some interest in probiotics after you read this article? If yes, feel free to read more about it by reading further and start your own research!

References, further reading, and links

Cleveland Clinic (2020). Probiotics: What is it, benefits, side effects, food & types. [online] Cleveland Clinic. Available at: https://my.clevelandclinic.org/health/articles/14598-probiotics.

Hemarajata, P. and Versalovic, J. (2012). Effects of probiotics on gut microbiota: mechanisms of intestinal immunomodulation and neuromodulation. Therapeutic Advances in Gastroenterology, [online] 6(1), pp.39–51. doi:https://doi.org/10.1177/1756283x12459294.

Kechagia, M., Basoulis, D., Konstantopoulou, S., Dimitriadi, D., Gyftopoulou, K., Skarmoutsou, N. and Fakiri, E.M. (2013). Health Benefits of Probiotics: A Review. ISRN Nutrition, [online] 2013, pp.1–7. doi:https://doi.org/10.5402/2013/481651.

Ravinder Nagpal, Ashwani Kumar, Manoj Kumar, Pradip V. Behare, Shalini Jain, Hariom Yadav, Probiotics, their health benefits and applications for developing healthier foods: a review, FEMS Microbiology Letters, Volume 334, Issue 1, September 2012, Pages 1–15, https://doi.org/10.1111/j.1574-6968.2012.02593.x