scholarly journals HUMAN GUT MICROBIOTA AND ITS EFFECTS ON HUMAN HEALTH IN NORMAL AND PATHOLOGICAL CONDITIONS

2017 ◽  
Vol 64 (3) ◽  
pp. 185-193
Author(s):  
Anca Magdalena Munteanu ◽  
◽  
Raluca Cursaru ◽  
Loreta Guja ◽  
Simona Carniciu ◽  
...  

The medical research of the last 1-2 decades allows us to look at the human gut microbiota and microbiome as to a structure that can promote health and sometimes initiate disease. It works like an endocrine organ: releasing specific metabolites, using environmental inputs, e.g. diet, or acting through its structural compounds, that signal human host receptors, to finally contributing to the pathogenesis of several gastrointestinal and non-gastrointestinal diseases. The same commensal microbes were found as shapers of the human host response to drugs (cardiovascular, oncology etc.). New technologies played an important role in these achievements, facilitating analysis of the genetic and metabolic profile of this microbial community. Once the inputs, the pathways and a lot of human host receptors were highlighted, the scientists were encouraged to go further into research, in order to develop new pathogenic therapies, targeting the human gut flora. Dual therapies, evolving these “friend microbes”, are another actual research subjects. This review gives an update on the current knowledge in the area of microbiota disbalances under environmental factors, the contribution of gut microbiota and microbiome to the pathogenesis of obesity, obesity associated metabolic disorders and cardiovascular disease, as well as new perspectives in preventing and treating these diseases, with high prevalence in contemporary, economically developed societies. It brings the latest and most relevant evidences relating to: probiotics, prebiotics, polyphenols and fecal microbiota transplantation, dietary nutrient manipulation, microbial as well as human host enzyme manipulation, shaping human responses to currently used drugs, manipulating the gut microbiome by horizontal gene transfer.

2016 ◽  
Vol 34 (3) ◽  
pp. 279-285 ◽  
Author(s):  
Giovanni Cammarota ◽  
Silvia Pecere ◽  
Gianluca Ianiro ◽  
Luca Masucci ◽  
Diego Currò

Fecal microbiota transplantation (FMT), a process by which the normal gastrointestinal microbiota is restored, has demonstrated extraordinary cure rates for Clostridium difficile infection and low recurrence. The community of microorganisms within the human gut (or microbiota) is critical to health status and functions; therefore, together with the rise of FMT, the gastrointestinal microbiota has emerged as a ‘virtual' organ with a level of complexity comparable to that of any other organ system and capable to compete with powerful known antibiotics for the treatment of several disorders. Although treatment protocols, donor selection, stool preparation and delivery methods varied widely, with a few reports following an identical protocol, FMT has diffused to other areas where the alterations of the gut microbiota ecology (or dysbiosis) have been theorized to play a causative role, including inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), among several other extra-intestinal disorders (i.e. metabolic syndrome and obesity, multiple sclerosis, cardiovascular diseases). FMT can be relatively simple to perform, but a number of challenges need to be overcome before this procedure is widely accepted in clinical practice, and currently, there is no consensus between the various gastrointestinal organizations and societies regarding the FMT procedure. In this article, we describe the modern high-throughput sequencing techniques to characterize the composition of gut microbiota and the potential for therapeutics by manipulating microbiota with FMT in several gastrointestinal disorders (C. difficile-associated diarrhea, IBD and IBS), with a look on the potential future directions of FMT.


2020 ◽  
Vol 8 (2) ◽  
pp. 200 ◽  
Author(s):  
Melina Kachrimanidou ◽  
Eleftherios Tsintarakis

Clostridioides difficile infection (CDI) has emerged as a major health problem worldwide. A major risk factor for disease development is prior antibiotic use, which disrupts the normal gut microbiota by altering its composition and the gut’s metabolic functions, leading to the loss of colonization resistance and subsequent CDI. Data from human studies have shown that the presence of C. difficile, either as a colonizer or as a pathogen, is associated with a decreased level of gut microbiota diversity. The investigation of the gut’s microbial communities, in both healthy subjects and patients with CDI, elucidate the role of microbiota and improve the current biotherapeutics for patients with CDI. Fecal microbiota transplantation has a major role in managing CDI, aiming at re-establishing colonization resistance in the host gastrointestinal tract by replenishing the gut microbiota. New techniques, such as post-genomics, proteomics and metabolomics analyses, can possibly determine in the future the way in which C. difficile eradicates colonization resistance, paving the way for the development of new, more successful treatments and prevention. The aim of the present review is to present recent data concerning the human gut microbiota with a focus on its important role in health and disease.


Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1024 ◽  
Author(s):  
Guillaume B. Fond ◽  
Jean-Christophe Lagier ◽  
Stéphane Honore ◽  
Christophe Lancon ◽  
Théo Korchia ◽  
...  

Background and significance. There is a need to develop new hypothesis-driven treatment for both both major depression (MD) and schizophrenia in which the risk of depression is 5 times higher than the general population. Major depression has been also associated with poor illness outcomes including pain, metabolic disturbances, and less adherence. Conventional antidepressants are partly effective, and 44% of the subjects remain unremitted under treatment. Improving MD treatment efficacy is thus needed to improve the SZ prognosis. Microbiota-orientated treatments are currently one of the most promising tracks. Method. This work is a systematic review synthetizing data of arguments to develop microbiota-orientated treatments (including fecal microbiota transplantation (FMT)) in major depression and schizophrenia. Results. The effectiveness of probiotic administration in MD constitutes a strong evidence for developing microbiota-orientated treatments. Probiotics have yielded medium-to-large significant effects on depressive symptoms, but it is still unclear if the effect is maintained following probiotic discontinuation. Several factors may limit MD improvement when using probiotics, including the small number of bacterial strains administered in probiotic complementary agents, as well as the presence of a disturbed gut microbiota that probably limits the probiotics’ impact. FMT is a safe technique enabling to improve microbiota in several gut disorders. The benefit/risk ratio of FMT has been discussed and has been recently improved by capsule administration. Conclusion. Cleaning up the gut microbiota by transplanting a totally new human gut microbiota in one shot, which is referred to as FMT, is likely to strongly improve the efficacy of microbiota-orientated treatments in MD and schizophrenia and maintain the effect over time. This hypothesis should be tested in future clinical trials.


2015 ◽  
Author(s):  
Elise R Morton ◽  
Joshua Lynch ◽  
Alain Froment ◽  
Sophie Lafosse ◽  
Evelyne Heyer ◽  
...  

The human gut microbiota is impacted by host nutrition and health status and therefore represents a potentially adaptive phenotype influenced by metabolic and immune constraints. Previous studies contrasting rural populations in developing countries to urban industrialized ones have shown that industrialization is strongly correlated with patterns in human gut microbiota; however, we know little about the relative contribution of factors such as climate, diet, medicine, hygiene practices, host genetics, and parasitism. Here, we focus on fine-scale comparisons of African rural populations in order to (i) contrast the gut microbiota of populations inhabiting similar environments but having different traditional subsistence modes and either shared or distinct genetic ancestry, and (ii) examine the relationship between gut parasites and bacterial communities. Characterizing the fecal microbiota of Pygmy hunter-gatherers as well as Bantu individuals from both farming and fishing populations in Southwest Cameroon, we found that the gut parasite Entamoeba is significantly correlated with microbiome composition and diversity. We show that across populations, colonization by this protozoa can be predicted with 79% accuracy based on the composition of an individual's gut microbiota, and that several of the taxa most important for distinguishing Entamoeba absence or presence are signature taxa for autoimmune disorders. We also found gut communities to vary significantly with subsistence mode, notably with some taxa previously shown to be enriched in other hunter-gatherers groups (in Tanzania and Peru) also discriminating hunter-gatherers from neighboring farming or fishing populations in Cameroon.


Author(s):  
Janneke Elzinga ◽  
John van der Oost ◽  
Willem M. de Vos ◽  
Hauke Smidt

SUMMARYThe human intestinal ecosystem is characterized by a complex interplay between different microorganisms and the host. The high variation within the human population further complicates the quest toward an adequate understanding of this complex system that is so relevant to human health and well-being. To study host-microbe interactions, defined synthetic bacterial communities have been introduced in gnotobiotic animals or in sophisticatedin vitrocell models. This review reinforces that our limited understanding has often hampered the appropriate design of defined communities that represent the human gut microbiota. On top of this, some communities have been applied toin vivomodels that differ appreciably from the human host. In this review, the advantages and disadvantages of using defined microbial communities are outlined, and suggestions for future improvement of host-microbe interaction models are provided. With respect to the host, technological advances, such as the development of a gut-on-a-chip system and intestinal organoids, may contribute to more-accuratein vitromodels of the human host. With respect to the microbiota, due to the increasing availability of representative cultured isolates and their genomic sequences, our understanding and controllability of the human gut “core microbiota” are likely to increase. Taken together, these advancements could further unravel the molecular mechanisms underlying the human gut microbiota superorganism. Such a gain of insight would provide a solid basis for the improvement of pre-, pro-, and synbiotics as well as the development of new therapeutic microbes.


2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Kai Zhan ◽  
Huan Zheng ◽  
Jianqing Li ◽  
Haomeng Wu ◽  
Shumin Qin ◽  
...  

The occurrence of diarrhea-predominant irritable bowel syndrome (IBS-D) is the result of multiple factors, and its pathogenesis has not yet been clarified. Emerging evidence indicates abnormal changes in gut microbiota and bile acid (BA) metabolism have a close relationship with IBS-D. Gut microbiota is involved in the secondary BA production via deconjugation, 7α-dehydroxylation, oxidation, epimerization, desulfation, and esterification reactions respectively. Changes in the composition and quantity of gut microbiota have an important impact on the metabolism of BAs, which can lead to the occurrence of gastrointestinal diseases. BAs, synthesized in the hepatocytes, play an important role in maintaining the homeostasis of gut microbiota and the balance of glucose and lipid metabolism. In consideration of the complex biological functional connections among gut microbiota, BAs, and IBS-D, it is urgent to review the latest research progress in this field. In this review, we summarized the alterations of gut microbiota in IBS-D and discussed the mechanistic connections between gut microbiota and BA metabolism in IBS-D, which may be involved in activating two important bile acid receptors, G-protein coupled bile acid receptor 1 (TGR5) and farnesoid X receptor (FXR). We also highlight the strategies of prevention and treatment of IBS-D via regulating gut microbiota-bile acid axis, including probiotics, fecal microbiota transplantation (FMT), cholestyramine, and the cutting-edge technology about bacteria genetic engineering.


2019 ◽  
Vol 7 (11) ◽  
pp. 544 ◽  
Author(s):  
Francesca Turroni ◽  
Sabrina Duranti ◽  
Christian Milani ◽  
Gabriele Andrea Lugli ◽  
Douwe van Sinderen ◽  
...  

Bifidobacteria typically represent the most abundant bacteria of the human gut microbiota in healthy breast-fed infants. Members of the Bifidobacterium bifidum species constitute one of the dominant taxa amongst these bifidobacterial communities and have been shown to display notable physiological and genetic features encompassing adhesion to epithelia as well as metabolism of host-derived glycans. In the current review, we discuss current knowledge concerning particular biological characteristics of the B. bifidum species that support its specific adaptation to the human gut and their implications in terms of supporting host health.


2020 ◽  
Author(s):  
Yeshi Yin ◽  
Miaomiao Li ◽  
Weizhong Gu ◽  
Benhua Zeng ◽  
Wei Liu ◽  
...  

Abstract Background: Carrageenans (CGNs) are widely used in food and pharmaceutical industries. However, the safety of CGNs is still under debate, because degraded CGNs have been reported to promote an intestinal inflammatory response in animal models. Here, we studied the relationship among CGNs, human gut microbiota, and the host inflammatory response.Methods: TLC was selected for detecting the degradation of KCPs by human gut microbiota in vitro batch fermentation system. PCR-DGGE and real time PCR were used for studying bacterial community. ESI-MS was used for KCPs structure analysis. Hematoxylin-eosin staining (HE), immunohistochemistry (IHC) and RNA-seq were used to evaluated the KCPs on host inflammation response in germ-free mice.Results: Thin-layer chromatography (TLC) data showed that CGNs with a molecular weight (Mw) higher than 100 kDa are not degraded by human fecal microbiota, but low Mw CGNs with an Mw around ~4.5 kDa (KCOs) could be degraded by seven of eight human fecal microbiota samples. KCO degrading B. xylanisolvens was isolated from fecal samples, and PCR-DGGE profiling with band sequencing suggested that B. xylanisolvens was the key KCO degrader in the human gut. Two putative κ-carrageenase genes were identified in the genome sequence of B. xylanisolvens. However, their function on KCO degrading was not verified in vitro. And the sulfate group from KCO is not removed after in vitro degradation by human fecal microbiota, as shown by ESI-MS analysis. The effects of KCO and KCO degrading bacteria on the inflammatory response were investigated in germ-free mice. Increased numbers of P-P38-, CD3a-, and CD79a-positive cells were found in the colon and rectum in mice fed with KCO plus KCO degrading bacteria than in mice fed with only KCO or only B. xylanisolvens and E. coli, as shown by RNA-Seq analysis, HE staining, and IHC. Conclusion: Our data suggested that the presence of KCO degrading bacteria promote the pro-inflammatory effects of CGNs.


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