Targeting gut microbiota dysbiosis in inflammatory bowel disease: a systematic review of current evidence

Abstract

Introduction: The dysbiosis of the gut microbiota has been identified as a central factor in the pathogenesis of inflammatory bowel disease (IBD), a chronic condition characterized by frequent recurrence and various adverse effects of traditional therapies. While treatments targeting the gut microbiota show promise, their efficacy in IBD management still requires extensive evaluation. Our systematic review analyzes recent studies to elucidate the advancements and challenges in treating IBD using microbial-based therapies.

Methods: Through a comprehensive systematic review spanning key scientific databases-PubMed, Embase, Cochrane, Web of Science, Scopus, and Google Scholar-we scrutinized the impact of probiotics, prebiotics, synbiotics, and fecal microbiota transplantation (FMT) on individuals with IBD. Our detailed analysis covered study and participant demographics, along with seven key outcome measures: disease activity index, inflammatory markers, serum cytokines, microbiome composition, adverse effects, and the rates of remission and relapse.

Results: From 6,080 initial search hits, we included 71 studies that assessed various interventions compared to placebo or standard medical therapy. Although there was notable variation in clinical results while assessing different outcomes, overall, probiotics, prebiotics, and synbiotics enhanced the success rates in inducing remission among IBD patients. Furthermore, we noted significant reductions in levels of pro-inflammatory markers and cytokines. Additionally, the requirement for steroids, hospitalization, and poor outcomes in endoscopic and histological scores were significantly reduced in individuals undergoing FMT.

Conclusion: Our investigation highlights the potential of targeting gut microbiota dysbiosis with microbial-based therapies in patients with IBD. We recommend conducting larger, placebo-controlled randomized trials with extended follow-up periods to thoroughly assess these treatments' clinical efficacy and safety before widespread recommendations for clinical application.

Keywords: Crohn’s disease; gastroenterology; inflammation; microbiology; ulcerative colitis.

Figure 1

PRISMA flow chart of study selection.

Figure 2

Number of used probiotics among reviewed clinical trials for patients with IBD. The figure shows that the most common probiotics used by different studies was L. acidophilus (14.5%) B. longum (10%) and L. plantarum (9%). The insert shows that 63% of the studies used multi strain comparing to 37% of the studies that used mono strain probiotic.

Figure 3

Frequency of prebiotics used among clinical trials for patients with IBD.

Figure 4

Future perspectives of gut microbiome research in IBD. (A) An improved study design will help addressing systematic biases and confounding variables by a thorough recording of fecal microbial composition, adjusting for potential confounders as well as implementing longitudinal study designs to explore the temporal relationships between microbiome shifts and the onset or progression. (B) Standardized approaches by adopting standardized approaches for inclusion and exclusion criteria, sample collection, processing, and data analysis which minimizes technical variability and facilitates meaningful cross-study comparisons. (C) Exploration of interactions between the gut microbiome and various factors—genetic, environmental, and clinical factors which holds immense promise for unraveling the pathophysiology of IBD. (D) Synergetic interactions by integrating microbiome modifications with existing preventive and therapeutic measures which presents a promising avenue for optimizing disease management in IBD.