MicroRNAs in inflammatory bowel disease:What do we know and what can we expect?

MicroRNAs(miRNAs),small non-coding RNAs composed of 18–24 nucleotides,are potent regulators of gene expression,contributing to the regulation of more than 30%of protein-coding genes.Considering that miRNAs are regulators of inflammatory pathways and the differentiation of intestinal epithelial cells,there is an interest in exploring their importance in inflammatory bowel disease(IBD).IBD is a chronic and multifactorial disease of the gastrointestinal tract;the main forms are Crohn's disease and ulcerative colitis.Several studies have investigated the dysregulated expression of miRNAs in IBD,demonstrating their important roles as regulators and potential biomarkers of this disease.This editorial presents what is known and what is expected regarding miRNAs in IBD.Although the important regulatory roles of miRNAs in IBD are clearly established,biomarkers for IBD that can be applied in clinical practice are lacking,emphasizing the importance of further studies.Discoveries regarding the influence of miRNAs on the inflammatory process and the exploration of their role in gene regulation are expected to provide a basis for the use of miRNAs not only as potent biomarkers in IBD but also as therapeutic targets for the control of inflammatory processes in personalized medicine.

Gut microbiota,inflammatory bowel disease and colorectal cancer

The gut microbiota is a complex community of microorganisms that inhabit the digestive tracts of humans,living in symbiosis with the host.Dysbiosis,characterized by an imbalance between the beneficial and opportunistic gut microbiota,is associated with several gastrointestinal disorders,such as irritable bowel syndrome(IBS);inflammatory bowel disease(IBD),represented by ulcerative colitis and Crohn’s disease;and colorectal cancer(CRC).Dysbiosis can disrupt the mucosal barrier,resulting in perpetuation of inflammation and carcinogenesis.The increase in some specific groups of harmful bacteria,such as Escherichia coli(E.coli)and enterotoxigenic Bacteroides fragilis(ETBF),has been associated with chronic tissue inflammation and the release of pro-inflammatory and carcinogenic mediators,increasing the chance of developing CRC,following the inflammationdysplasia-cancer sequence in IBD patients.Therefore,the aim of the present review was to analyze the correlation between changes in the gut microbiota and the development and maintenance of IBD,CRC,and IBD-associated CRC.Patients with IBD and CRC have shown reduced bacterial diversity and abundance compared to healthy individuals,with enrichment of Firmicute sand Bacteroidetes.Specific bacteria are also associated with the onset and progression of CRC,such as Fusobacterium nucleatum,E.coli,Enterococcus faecalis,Streptococcus gallolyticus,and ETBF.Future research can evaluate the advantages of modulating the gut microbiota as preventive measures in CRC high-risk patients,directly affecting the prognosis of the disease and the quality of life of patients.