Microbes, the immune system, and the health benefits of exposure to the natural environment

Author(s):  
Graham Rook

Humans, like essentially all complex multicellular animals, are ecosystems. We evolved in symbiosis with microorganisms, notably the ~1,014 organisms in the gut microbiota that provide signals for organ development, perform multiple digestive and metabolic services, and educate the immune system. Humans also evolved to tolerate certain ‘old infections’ that could persist for life in small hunter-gatherer groups. Modern medicine eliminates the ‘old infections’, while the urban lifestyle reduces our contact with organisms from other humans, animals, and the natural environment that contribute to the microbiotas, while increasing our exposure to the more recently evolved crowd infections. These changes compromise regulation of the immune system and increase the prevalence of chronic inflammatory disorders. Changes to the microbiota also predispose to metabolic disturbances. We need to restore our interaction with the natural environment because it is a reservoir of genetic and metabolic flexibility, and it fine-tunes regulation of the immune system.

2017 ◽  
Vol 8 (10) ◽  
pp. 3758-3768 ◽  
Author(s):  
Elvira Sánchez-Samper ◽  
Carlos Gómez-Gallego ◽  
Pedro Andreo-Martínez ◽  
Seppo Salminen ◽  
Gaspar Ros

Infant food profile on programming of the growth, gut microbiota and immune system of C57BL/6J mice.


Author(s):  
Graham A. W. Rook

As humans move from the natural environment in which we evolved into modern urban settings, there are striking increases in chronic inflammatory and psychiatric disorders. To understand and eventually take control of this phenomenon we have to understand how humans, and in particular our immune systems, evolved in partnership with microorganisms in the environment and in our own bodies. Humans are holobionts, composed of human cells containing the human genome passed on via the germline, but also a much larger number of microbial cells acquired from mother, family members, and the environment. This microbiota provides signals involved in the development of essentially all organ systems, including the brain, and provides data and signals that regulate metabolism and the immune system. The immune system evolved to perform the dual functions of managing this microbiota, while simultaneously protecting us from pathogens. By considering the evolution of the immune system and the ways in which lifestyle changes have altered our exposures to, and colonisation by microorganisms, we can identify the crucial factors leading to the modern urban pattern of disease.


2021 ◽  
Vol 12 ◽  
Author(s):  
Anna Torun ◽  
Anna Hupalowska ◽  
Piotr Trzonkowski ◽  
Jaroslaw Kierkus ◽  
Beata Pyrzynska

The incidence and prevalence rate of chronic inflammatory disorders is on the rise in the pediatric population. Recent research indicates the crucial role of interactions between the altered intestinal microbiome and the immune system in the pathogenesis of several chronic inflammatory disorders in children, such as inflammatory bowel disease (IBD) and autoimmune diseases, such as type 1 diabetes mellitus (T1DM) and celiac disease (CeD). Here, we review recent knowledge concerning the pathogenic mechanisms underlying these disorders, and summarize the facts suggesting that the initiation and progression of IBD, T1DM, and CeD can be partially attributed to disturbances in the patterns of composition and abundance of the gut microbiota. The standard available therapies for chronic inflammatory disorders in children largely aim to treat symptoms. Although constant efforts are being made to maximize the quality of life for children in the long-term, sustained improvements are still difficult to achieve. Additional challenges are the changing physiology associated with growth and development of children, a population that is particularly susceptible to medication-related adverse effects. In this review, we explore new promising therapeutic approaches aimed at modulation of either gut microbiota or the activity of the immune system to induce a long-lasting remission of chronic inflammatory disorders. Recent preclinical studies and clinical trials have evaluated new approaches, for instance the adoptive transfer of immune cells, with genetically engineered regulatory T cells expressing antigen-specific chimeric antigen receptors. These approaches have revolutionized cancer treatments and have the potential for the protection of high-risk children from developing autoimmune diseases and effective management of inflammatory disorders. The review also focuses on the findings of studies that indicate that the responses to a variety of immunotherapies can be enhanced by strategic manipulation of gut microbiota, thus emphasizing on the importance of proper interaction between the gut microbiota and immune system for sustained health benefits and improvement of the quality of life of pediatric patients.


2020 ◽  
Vol 21 (8) ◽  
pp. 785-798 ◽  
Author(s):  
Abedin Abdallah ◽  
Evera Elemba ◽  
Qingzhen Zhong ◽  
Zewei Sun

The gastrointestinal tract (GIT) of humans and animals is host to a complex community of different microorganisms whose activities significantly influence host nutrition and health through enhanced metabolic capabilities, protection against pathogens, and regulation of the gastrointestinal development and immune system. New molecular technologies and concepts have revealed distinct interactions between the gut microbiota and dietary amino acids (AAs) especially in relation to AA metabolism and utilization in resident bacteria in the digestive tract, and these interactions may play significant roles in host nutrition and health as well as the efficiency of dietary AA supplementation. After the protein is digested and AAs and peptides are absorbed in the small intestine, significant levels of endogenous and exogenous nitrogenous compounds enter the large intestine through the ileocaecal junction. Once they move in the colonic lumen, these compounds are not markedly absorbed by the large intestinal mucosa, but undergo intense proteolysis by colonic microbiota leading to the release of peptides and AAs and result in the production of numerous bacterial metabolites such as ammonia, amines, short-chain fatty acids (SCFAs), branched-chain fatty acids (BCFAs), hydrogen sulfide, organic acids, and phenols. These metabolites influence various signaling pathways in epithelial cells, regulate the mucosal immune system in the host, and modulate gene expression of bacteria which results in the synthesis of enzymes associated with AA metabolism. This review aims to summarize the current literature relating to how the interactions between dietary amino acids and gut microbiota may promote host nutrition and health.


2020 ◽  
Vol 19 (7) ◽  
pp. 509-526
Author(s):  
Qin Huang ◽  
Fang Yu ◽  
Di Liao ◽  
Jian Xia

: Recent studies implicate microbiota-brain communication as an essential factor for physiology and pathophysiology in brain function and neurodevelopment. One of the pivotal mechanisms about gut to brain communication is through the regulation and interaction of gut microbiota on the host immune system. In this review, we will discuss the role of microbiota-immune systeminteractions in human neurological disorders. The characteristic features in the development of neurological diseases include gut dysbiosis, the disturbed intestinal/Blood-Brain Barrier (BBB) permeability, the activated inflammatory response, and the changed microbial metabolites. Neurological disorders contribute to gut dysbiosis and some relevant metabolites in a top-down way. In turn, the activated immune system induced by the change of gut microbiota may deteriorate the development of neurological diseases through the disturbed gut/BBB barrier in a down-top way. Understanding the characterization and identification of microbiome-immune- brain signaling pathways will help us to yield novel therapeutic strategies by targeting the gut microbiome in neurological disease.


Biologics ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 89-110
Author(s):  
Neslihan Yeşilyurt ◽  
Birsen Yılmaz ◽  
Duygu Ağagündüz ◽  
Raffaele Capasso

Intestinal microbiota interacts with other systems, especially the immune system, which is responsible for protecting the body by recognizing “stranger” (pathogen associated molecular patterns-PAMPs) and “danger” (damage-associated molecular patterns-DAMPs) molecular motifs. In this manner, it plays an important role in the pathogenesis of various diseases and health. Despite the use of probiotics that modulate the intestinal microbiota in providing health benefits and in the treatment of diseases, there are some possible concerns about the possibility of developing adverse effects, especially in people with suppressed immune systems. Since probiotics provide health benefits with bioactive compounds, studies are carried out on the use of products containing non-living probiotic microorganisms (paraprobiotics) and/or their metabolites (postbiotics) instead of probiotic products. It is even reported that these microbial compounds have more immunomodulatory activities than living microorganisms via some possible mechanism and eliminates some disadvantages of probiotics. Considering the increasing use of functional foods in health and disease, further studies are needed with respect to the benefits and advantages of parabiotic and/or postbiotic use in the food and pharmaceutical industry as well as immune system modulation. Although probiotics have been extensive studied for a long time, it seems that postbiotics are promising tools for future research and applications according to the recent literature. This review aimed to evaluate the interaction of probiotics and postbiotics with the immune systems and also their advantages and disadvantages in the area of food-pharmaceutical industry and immune system modulation.


Author(s):  
Gaoxing Ma ◽  
Hengjun Du ◽  
Qiuhui Hu ◽  
Wenjian Yang ◽  
Fei Pei ◽  
...  

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 699
Author(s):  
Cielo García-Montero ◽  
Oscar Fraile-Martínez ◽  
Ana M. Gómez-Lahoz ◽  
Leonel Pekarek ◽  
Alejandro J. Castellanos ◽  
...  

The most prevalent diseases of our time, non-communicable diseases (NCDs) (including obesity, type 2 diabetes, cardiovascular diseases and some types of cancer) are rising worldwide. All of them share the condition of an “inflammatory disorder”, with impaired immune functions frequently caused or accompanied by alterations in gut microbiota. These multifactorial maladies also have in common malnutrition related to physiopathology. In this context, diet is the greatest modulator of immune system–microbiota crosstalk, and much interest, and new challenges, are arising in the area of precision nutrition as a way towards treatment and prevention. It is a fact that the westernized diet (WD) is partly responsible for the increased prevalence of NCDs, negatively affecting both gut microbiota and the immune system. Conversely, other nutritional approaches, such as Mediterranean diet (MD), positively influence immune system and gut microbiota, and is proposed not only as a potential tool in the clinical management of different disease conditions, but also for prevention and health promotion globally. Thus, the purpose of this review is to determine the regulatory role of nutritional components of WD and MD in the gut microbiota and immune system interplay, in order to understand, and create awareness of, the influence of diet over both key components.


2021 ◽  
Vol 22 (13) ◽  
pp. 6933
Author(s):  
Yuqi Wu ◽  
Chong-Zhi Wang ◽  
Jin-Yi Wan ◽  
Haiqiang Yao ◽  
Chun-Su Yuan

The gut microbiota exists throughout the full life cycle of the human body, and it has been proven to have extensive impacts on health and disease. Accumulating evidence demonstrates that the interplay between gut microbiota and host epigenetics plays a multifaceted role in health maintenance and disease prevention. Intestinal microflora, along with their metabolites, could regulate multiple epigenetic pathways; e.g., DNA methylation, miRNA, or histone modification. Moreover, epigenetic factors can serve as mediators to coordinate gut microbiota within the host. Aiming to dissect this interplay mechanism, the present review summarizes the research profile of gut microbiota and epigenetics in detail, and further interprets the biofunctions of this interplay, especially the regulation of intestinal inflammation, the improvement of metabolic disturbances, and the inhibition of colitis events. This review provides new insights into the interplay of epigenetics and gut microbiota, and attempts to reveal the mysteries of health maintenance and disease prevention from this new perspective.


Physiology ◽  
2012 ◽  
Vol 27 (5) ◽  
pp. 300-307 ◽  
Author(s):  
Rémy Burcelin

The recent epidemic of obesity and diabetes and the diversity at the individual level could be explained by the intestinal microbiota-to-host relationship. More than four million gene products from the microbiome could interact with the immune system to induce a tissue metabolic infection, which is the molecular origin of the low-grade inflammation that characterizes the onset of obesity and diabetes.


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