Recent Advances in the Etiopathogenesis of Inflammatory Bowel Disease: The Role of Omics

Immunoepigenetic Regulation of Inflammatory Bowel Disease: Current Insights into Novel Epigenetic Modulations of the Systemic Immune Response

The immune system and environmental factors are involved in various diseases, such as inflammatory bowel disease (IBD), through their effect on genetics, which modulates immune cells. IBD encompasses two main phenotypes, Crohn’s disease, and ulcerative colitis, which are manifested as chronic and systemic relapse-remitting gastrointestinal tract disorders with rising global incidence and prevalence. The pathophysiology of IBD is complex and not fully understood. Epigenetic research has resulted in valuable information for unraveling the etiology of this immune-mediated disease. Thus, the main objective of the present review is to summarize the current findings on the role of epigenetic mechanisms in IBD to shed light on their potential clinical relevance. This review focuses on the latest evidence regarding peripheral blood mononuclear cells and epigenetic changes in histone modification, DNA methylation, and telomere shortening in IBD. The various identified epigenetic DNA profiles with clinical value in IBD could be used as biomarkers for more accurately predicting disease development, treatment response, and therapy-related adverse events. Ultimately, the information presented here could be of potential relevance for future clinical practice in developing more efficient and precise medicine to improve the quality of life for patients with IBD.

Influence of Rectal Ozone Application on the Intensity of Free Radical Destruction of Lipids and Intestinal Proteins in the Dynamics of Experimental Colitis

We studied clinical status, content of products of LPO, and oxidative modification of proteins (OMP) in the lesion focus of the intestine in experimental colitis under conditions of rectal administration of ozone. Experimental colitis was simulated by two-stage administration of oxazolone; rectal insufflation of ozone in the ozone-oxygen mixture was performed daily. The disease activity index (DAI), the content of calprotectin in the feces, and LPO and OMP products in the intestinal homogenate were assessed. On days 2, 4, and 6 of the pathological process, DAI, concentration of calprotectin in feces, content of primary, secondary, and end-products of LPO in the heptane and isopropanol phases, and content of primary and secondary OMP products progressively increases. Under conditions of ozone application, DAI, concentration of calprotectin in feces, the levels of heptane- and isopropanol-soluble primary, secondary, and end-products of LPO, and the level of primary and secondary products of OMP decreased on days 4 and 6; the level of isopropanol-soluble primary, secondary, end-products of LPO increased on day 2 of experimental colitis. The severity of clinical manifestations weakens as the content of LPO and OMP products in the colon decreases on days 4 and 6 of observation.

Immunological Networks Defining the Heterogeneity of Inflammatory Bowel Diseases

Current practice in IBD is to classify patients based on clinical signs and symptoms and provide treatments accordingly. However, the response of IBD patients to available treatments is highly variable, highlighting clinically significant heterogeneity among patients. Thus, more accurate patient stratification is urgently needed to more effectively target therapeutic interventions to specific patients. Here we review the degree of heterogeneity in IBD, discussing how the microbiota, genetics, and immune system may contribute to the variation among patients. We highlight how molecular heterogeneity may relate to clinical phenotype, but in other situations may be independent of clinical phenotype, encouraging future studies to fill the gaps. Finally, we discuss novel stratification methodologies as a foundation for precision medicine, in particular a novel stratification strategy based on conserved genes across species. All of these dimensions of heterogeneity have potential to provide strategies for patient stratification and move IBD practice towards personalised medicine.

Inflammatory bowel disease: tri-directional relationship between microbiota, immune system and intestinal epithelium

Human gut microbiota contributes to host nutrition and metabolism, sustains intestinal cell proliferation and differentiation, and modulates host immune system. The alterations in their composition lead to severe gut disorders, including inflammatory bowel disease (IBD) or inflammatory bowel syndrome (IBS). IBD including ulcerative colitis (UC) and Crohn's disease (CD) are gamut of chronic inflammatory disorders of gut, mediated by complex interrelations among genetic, environmental, and internal factors. IBD has debateable aetiology, however in recent years, exploring the central role of a tri-directional relationship between gut microbiota, mucosal immune system, and intestinal epithelium in pathogenesis is getting the most attention. Increasing incidences and early onset explains the exponential rise in IBD burden on health-care systems. Industrialization, hypersensitivity to allergens, lifestyle, hygiene hypothesis, loss of intestinal worms, and gut microbial composition, explains this shifted rise. Hitherto, the interventions modulating gut microbiota composition, microfluidics-based in vitro gastrointestinal models, non-allergic functional foods, nutraceuticals, and faecal microbiota transplantation (FMT) from healthy donors are some of the futuristic approaches for the disease management.

What's new in IBD therapy: An "omics network" approach

The industrial revolution that began in the late 1800s has resulted in dramatic changes in the environment, human lifestyle, dietary habits, social structure, and so on. Almost certainly because this rapid evolution has outpaced the ability of the body to adapt to a number of environmental and behavioral changes, there has been a parallel emergence of several chronic inflammatory diseases, among which are inflammatory bowel diseases (IBD), primarily ulcerative colitis and Crohn's disease. The ability to treat these conditions has progressively improved in the last 50 years, particularly in the last couple of decades with the introduction of biological therapy targeting primarily soluble mediators produced by inflammatory cells. A large number of biologics are now available, but all of them induce similarly unsatisfactory (<50%) rates of clinical response and remission, and most of them lose efficacy over time, requiring dose escalation or switching from one biologic to another. So, treatment of IBD still needs improvement that will occur only if different approaches are taken. A reason why even the most recent forms of IBD therapy are unsatisfactory is because they target only selected components of an exceedingly complex pathophysiological process, a reality that must be honestly considered if better IBD therapies are to be achieved. Brand new approaches must integrate all relevant factors in their totality - the "omes" - and identify the key controllers of biological responses. This can be accomplished by using systems biology-based approaches and advanced bioinformatics tools, which together represent the essence of network medicine. This review looks at the past and the present of IBD pathogenesis and therapy, and discusses how to develop new therapies based on a network medicine approach.

THE ONSET OF CLINICAL MANIFESTATIONS IN INFLAMMATORY BOWEL DISEASE PATIENTS

BACKGROUND

The diagnosis of inflammatory bowel disease is often delayed because of the lack of an ability to recognize its major clinical manifestations.

OBJECTIVE

Our study aimed to describe the onset of clinical manifestations in inflammatory bowel disease patients.

METHODS

A cross-sectional study. Investigators obtained data from interviews and the medical records of inflammatory bowel disease patients from a reference centre located in Brazil.

RESULTS

A total of 306 patients were included. The mean time between onset of symptoms and diagnosis was 28 months for Crohn's disease and 19 months for ulcerative colitis. The main clinical manifestations in Crohn's disease patients were weight loss, abdominal pain, diarrhoea and asthenia. The most relevant symptoms in ulcerative colitis patients were blood in the stool, faecal urgency, diarrhoea, mucus in the stool, weight loss, abdominal pain and asthenia. It was observed that weight loss, abdominal pain and distension, asthenia, appetite loss, anaemia, insomnia, fever, nausea, perianal disease, extraintestinal manifestation, oral thrush, vomiting and abdominal mass were more frequent in Crohn's patients than in ulcerative colitis patients. The frequencies of urgency, faecal incontinence, faeces with mucus and blood, tenesmus and constipation were higher in ulcerative colitis patients than in Crohn's disease patients. The mean time from the onset of clinical symptoms to the diagnosis of Crohn's disease was 37 months for patients with ileocolonic location, 26 months for patients with ileum location and 18 months for patients with colon location. In ulcerative colitis patients, the mean time from the onset of symptoms to diagnosis was 52 months for proctitis, 12 months for left-sided colitis and 12 months for extensive colitis.

CONCLUSION

Ulcerative colitis presented a high frequency of intestinal symptoms, and Crohn's disease showed a high frequency of systemic manifestations at the onset of manifestation. There was a long delay in diagnosis, but individuals with more extensive disease and more obvious symptoms showed a shorter delay.