The genetic burden of inflammatory bowel diseases: implications for the clinic?

Genetic and Epigenetic Etiology of Inflammatory Bowel Disease: An Update

Inflammatory bowel disease (IBD) is a chronic disease with periods of exacerbation and remission of the disease. The etiology of IBD is not fully understood. Many studies point to the presence of genetic, immunological, environmental, and microbiological factors and the interactions between them in the occurrence of IBD. The review looks at genetic factors in the context of both IBD predisposition and pharmacogenetics.

Inflammatory Bowel Disease: Updates on Molecular Targets for Biologics

Therapy for inflammatory bowel disease (IBD) has changed, with several new agents being evaluated. The era of anti-tumor necrosis factor (anti-TNF) antibody therapy saw remarkable progress in IBD therapy. Some patients, however, do not respond to anti-TNF treatment, or their response decreases over time. This phenomenon highlights the need to identify new molecular targets for therapy in IBD. The targets of new therapeutic molecules in IBD must aim to restore immune dysregulation by the inhibition of proinflammatory cytokines (TNF-α, interleukin [IL]-6, IL-13, IL-17, IL-18, and IL-21) and augmentation of the effect of anti-inflammatory cytokines (IL-10, IL-11, and transforming growth factor β) and to pursue new anti-inflammatory targets, such as regulatory T-cell therapy, Smad7 antisense, Janus-activated kinase inhibition, Toll-like receptor stimulation, leukocyte adhesion, and blockade of T-cell homing via integrins and mucosal addressin cellular adhesion molecule-1. In addition, potential molecular targets could restore mucosal barrier function and stimulate mucosal healing. Despite these potential targets, the value and clinical significance of most new molecules remain unclear, and clinical efficacy and safety must be better defined before their implementation in clinical practice. This article aims to review the promising and emerging molecular targets that could be clinically meaningful for novel therapeutic approaches.

The Innate and Adaptive Immune System as Targets for Biologic Therapies in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an immune-mediated inflammatory condition causing inflammation of gastrointestinal and systemic cells, with an increasing prevalence worldwide. Many factors are known to trigger and maintain inflammation in IBD including the innate and adaptive immune systems, genetics, the gastrointestinal microbiome and several environmental factors. Our knowledge of the involvement of the immune system in the pathophysiology of IBD has advanced rapidly over the last two decades, leading to the development of several immune-targeted treatments with a biological source, known as biologic agents. The initial focus of these agents was directed against the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) leading to dramatic changes in the disease course for a proportion of patients with IBD. However, more recently, it has been shown that a significant proportion of patients do not respond to anti-TNF-α directed therapies, leading a shift to other inflammatory pathways and targets, including those of both the innate and adaptive immune systems, and targets linking both systems including anti-leukocyte trafficking agents-integrins and adhesion molecules. This review briefly describes the molecular basis of immune based gastrointestinal inflammation in IBD, and then describes how several current and future biologic agents work to manipulate these pathways, and their clinical success to date.