Role of Gut Microbiota in Inflammatory Bowel Disease: Insights from Human Studies

Carry F. Dune^*
*Correspondence: Carry F. Dune, Department of Gastroenterology, Nancy University Hospital, Vandoeuvre-lès-Nancy, France, Email:

Introduction

Inflammatory Bowel Disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract characterized by unpredictable bouts of remission and relapse. The etiology of IBD remains elusive, but emerging evidence suggests a significant role of the gut microbiota in its pathogenesis. This review examines the intricate relationship between gut microbiota and IBD, exploring how dysbiosis, or an imbalance in the microbial community, contributes to inflammation and disease progression. We discuss the impact of various factors, including genetics, diet, and environmental influences, on shaping the gut microbiota composition in individuals with IBD [1]. Additionally, we explore the potential of microbiota-based therapies, such as probiotics, prebiotics, and fecal microbiota transplantation, in modulating the gut microbiota and ameliorating IBD symptoms. Understanding the complex interplay between gut microbiota and IBD holds promise for developing personalized therapeutic interventions to manage this debilitating condition effectively.

Description

Elucidating how dysbiosis contributes to inflammation and disrupts intestinal homeostasis is crucial for understanding IBD pathogenesis. Studies have shown alterations in the abundance and diversity of gut microbiota in individuals with IBD compared to healthy controls. Specific microbial taxa, such as certain species of Firmicutes and Proteobacteria, have been associated with inflammation and disease severity in IBD. Genetic predisposition, environmental factors, dietary habits, antibiotic use, and host-microbiota interactions all influence the composition of the gut microbiota in individuals with IBD. Genetic susceptibility may modulate host responses to microbial stimuli, contributing to dysbiosis and aberrant immune activation. Environmental factors, such as lifestyle choices and exposure to pollutants, can shape the gut microbiota and exacerbate inflammatory responses in susceptible individuals.

Probiotics, prebiotics, and fecal microbiota transplantation have emerged as potential therapeutic strategies for modulating the gut microbiota and alleviating IBD symptoms. Probiotics containing beneficial microbial strains, such as Lactobacillus and Bifidobacterium species, may help restore microbial balance and enhance intestinal barrier function. Prebiotics, such as dietary fibers, promote the growth of beneficial bacteria in the gut, thereby exerting anti-inflammatory effects [2]. FMT, which involves transferring fecal microbiota from healthy donors to individuals with IBD, aims to restore microbial diversity and function, leading to clinical improvement in some cases. Despite the promise of microbiota-based therapies, several challenges remain, including the need for personalized treatment approaches, standardization of FMT protocols, and long-term safety concerns. Future research should focus on elucidating the mechanisms underlying host-microbiota interactions in IBD and identifying microbial biomarkers for disease diagnosis and prognosis. Moreover, large-scale clinical trials are warranted to evaluate the efficacy and safety of microbiota-based interventions in diverse patient populations. In conclusion, the gut microbiota plays a pivotal role in the pathogenesis of IBD, offering new avenues for therapeutic intervention. By elucidating the complex interplay between gut microbiota and host immune responses, we can develop personalized treatment strategies to improve outcomes for individuals living with IBD.

Human studies investigating the role of gut microbiota in IBD have employed various methodologies, including metagenomic sequencing, microbial profiling, and functional analyses of microbial communities. These studies have revealed alterations in the composition, diversity [3], and function of the gut microbiota in individuals with IBD compared to healthy controls. Specifically, reductions in microbial diversity, alterations in microbial taxa abundance, and dysregulation of microbial metabolic pathways have been observed in IBD patients, suggesting a disruption of the gut microbial ecosystem. Furthermore, longitudinal studies have highlighted dynamic changes in the gut microbiota associated with disease activity, treatment response, and disease progression in IBD patients. For example, shifts in microbial composition and function have been observed during disease flares and remissions, suggesting a bidirectional relationship between gut dysbiosis and IBD pathophysiology. Additionally, alterations in the gut microbiota have been implicated in the development of extra-intestinal manifestations of IBD, such as arthritis, dermatologic disorders, and hepatic complications, highlighting the systemic effects of gut dysbiosis in IBD patients.

Importantly, human studies have identified potential microbial biomarkers of IBD, which may aid in disease diagnosis, prognosis, and treatment stratification. By characterizing microbial signatures associated with different disease phenotypes, clinical outcomes, and treatment responses, researchers have identified microbial biomarkers that may serve as diagnostic tools or therapeutic targets in IBD management. Additionally, studies investigating the role of dietary interventions, prebiotics, probiotics, and fecal microbiota transplantation have provided evidence for the therapeutic potential of modulating the gut microbiota in IBD. Human studies have significantly advanced our understanding of the role of gut microbiota in inflammatory bowel disease [4]. Through meticulous examination of microbial composition in IBD patients compared to healthy individuals, researchers have uncovered patterns of dysbiosis that correlate with disease severity and progression. These studies have identified specific microbial taxa associated with inflammation, such as increased levels of Proteobacteria and reduced abundance of anti-inflammatory species like Faecalibacterium prausnitzii. Moreover, investigations into host-microbiota interactions have revealed how genetic predisposition, environmental factors, and immune dysregulation influence microbial composition and contribute to IBD pathogenesis. Understanding these intricate relationships is crucial for developing targeted interventions aimed at restoring microbial balance and attenuating inflammation in IBD patients. Furthermore, human studies have underscored the impact of environmental factors on gut microbiota composition and IBD risk. Lifestyle choices, such as diet and antibiotic use, play a significant role in shaping microbial diversity and function in the gut. Westernized diets high in processed foods and low in fiber have been linked to dysbiosis and increased inflammation in individuals with IBD. Conversely, dietary interventions rich in plant-based foods and fermented products have shown promise in modulating the gut microbiota and improving clinical outcomes in IBD patients. Additionally, antibiotic exposure during critical periods of gut development may disrupt microbial colonization and predispose individuals to IBD later in life [5]. These findings highlight the importance of considering environmental factors in conjunction with host genetics and microbial dysbiosis when exploring the pathogenesis of IBD and developing targeted therapeutic strategies.

Conclusion

Human studies have provided valuable insights into the role of gut microbiota in IBD, elucidating the complex interactions between microbial communities, host immune responses, and environmental factors in disease pathogenesis. By leveraging advanced sequencing technologies, multi-omics approaches, and longitudinal analyses, researchers have made significant strides in understanding the dynamic nature of the gut microbiota in IBD. Moving forward, further research is needed to elucidate the causal relationships between gut dysbiosis and IBD, identify microbial biomarkers of disease activity and progression, and develop targeted interventions to restore gut microbial homeostasis in IBD patients. By advancing our understanding of the role of gut microbiota in IBD through human studies, we can pave the way for personalized approaches to diagnosis, treatment, and management of this complex and debilitating condition.

Acknowledgement

None.

Conflict of Interest

None.

References

1. Hu, Jia-Chen E., Franziska Weiß, Christian Bojarski and Federica Branchi, et al. "Expression of tricellular tight junction proteins and the paracellular macromolecule barrier are recovered in remission of ulcerative colitis." BMC Gastroenterol 21 (2021): 1-11.

Google Scholar, Crossref, Indexed at

2. Söderholm, Johan D., Kajsa Holmgren Peterson, Gunnar Olaison and Lennart E. Franzén, et al. "Epithelial permeability to proteins in the noninflamed ileum of Crohn's disease?" Gastroenterol 117 (1999): 65-72.

Google Scholar, Crossref, Indexed at

3. Annese, Vito, Dana Duricova, Corinne Gower-Rousseau and Tine Jess, et al. "Impact of new treatments on hospitalisation, surgery, infection, and mortality in IBD: a focus paper by the epidemiology committee of ECCO." J Crohn's Colitis 10 (2016): 216-225.

Google Scholar, Crossref, Indexed at

4. Karstensen, John Gásdal, Adrian Săftoiu, Jørn Brynskov and Jakob Hendel, et al. "Confocal laser endomicroscopy: a novel method for prediction of relapse in Crohn’s disease." Endoscopy 48 (2016): 364-372.

Google Scholar, Crossref, Indexed at

5. Solitano, Virginia, Ferdinando D’Amico, Leonardo Da Rio and Laurent Peyrin-Biroulet, et al. "The European perspective and history on biosimilars for the treatment of inflammatory bowel diseases." J Crohn's Colitis 360 (2021): otab012.

Google Scholar, Crossref, Indexed at