Current Understanding of Dysbiosis in Disease in Human and Animal Models

Abstract

Inflammatory bowel disease (IBD) is an intestinal inflammatory condition that affects over two million people in the United States. Although the etiology and pathogenesis of IBD are still largely unknown, dysregulated host/enteric microbial interactions are requisite for the development of IBD. So far, many researchers have tried to identify a precise relationship between IBD and an imbalance of the intestinal microbiota, termed “dysbiosis”. In spite of the extensive efforts, it is still largely unknown about the interplay among microbes, their hosts, and their environments, and whether dysbiosis is a causal factor or an effect of IBD. Recently, deep-sequencing analyses of the microbiota in IBD patients have been instrumental in characterizing the strong association between dysbiosis and IBD development, although it is still unable to identify specific-associated species level changes in most cases. Based on many recent reports, dysbiosis of the commensal microbiota is implicated in the pathogenesis of several diseases, including IBD, obesity, and allergic disorders, in both human and animal models. In this review article, we have focused on explaining the multiple types of dysbiosis, as well as dysbiosis-related diseases and potential treatments in order to apply this knowledge to understand a possible cause and potentially find therapeutic strategies for IBD as well as the other dysbiosis-related diseases.

Helicobacter species are potent drivers of colonic T cell responses in homeostasis and inflammation

“…Our initial goal was to study the T cell response to alterations in gut microbiota structure, a.k.a dysbiosis, that occurs with colitis and inflammatory bowel disease (IBD) and has been proposed to be involved in disease pathogenesis (4, 36, 37). However, rather than observing a dominant effector T cell response to Bacteroides spp.…”

The ecological community of commensal, symbiotic, and pathogenic gastrointestinal microorganisms – an appraisal

“…The identification of various alterations of the gut microbiota composition in IBD has enabled using very advanced next-generation sequencing technology 145. Alterations in the ecological system have been reported within the gut, that is, intestinal microbes and the immune system 146,147. “The most consistent observation in IBD is reduced bacterial diversity, a decrease of Firmicutes, and an increase of Proteobacteria.”145 Although many factors such as “host, genetic, and environmental” influences have been identified as for the pathogenesis of IBD,140 currently, only smoking has been identified as the most potential and specific environmental factor for the onset of IBD 148–150…”

Novel perspectives on the role of the human microbiota in regenerative medicine and surgery

“…A successful example of microbiota transfer as a therapeutic tool against dysbiosis (an imbalance between beneficial and potentially harmful bacteria) (66) has been accomplished through fecal transplantation in patients affected by recurrent enteric Clostridium difficile infections. The microbiota of healthy donor feces reconstitutes the compromised intestinal microbiota in a substantial and durable way (67).…”