Impact of Genes and the Environment on the Pathogenesis and Disease Course of Inflammatory Bowel Disease

Does Elderly-Onset Inflammatory Bowel Disease Increase Risk of Colorectal Cancer? A Systematic Review and Meta-Analysis

BACKGROUND

Although younger adults with inflammatory bowel disease (IBD) are known to have an increased risk of developing colorectal cancer (CRC), the impact of IBD on CRC risk in elderly patients is not yet fully understood. Therefore, we conducted this systematic review and meta-analysis to address this knowledge gap.

METHODS

We thoroughly searched Embase, PubMed, and Scopus, covering the literature from inception to 31 August 2023, in any language. We enrolled population-based cohort studies that appraised the risk of CRC development in elderly patients (≥60 years) with IBD as compared to the non-IBD population. Our meta-analysis provided pooled relative risk (RR) with 95% confidence intervals (CIs) using a random-effect model.

RESULTS

Out of 3904 citations, 3 eligible cohort studies were ultimately included, reporting 694 CRC events in 35,187 patients with IBD. According to analysis, the risk of developing CRC did not increase in patients with elderly-onset IBD (RR = 1.17 [95% CI: 0.86-1.47]; I2 = 62.6%). This lack of a significant association was observed in both patients with Crohn's disease (RR = 1.28 [95% CI: 0.88-1.69]) and ulcerative colitis (RR = 0.99 [95% CI: 0.90-1.09]) (p for interaction = 0.166).

CONCLUSION

Our findings revealed no significant increase in the risk of incident CRC in patients with elderly-onset IBD, suggesting that intense screening of these patients for CRC may not be necessary.

Long Non-Coding RNAs and Their "Discrete" Contribution to IBD and Johne's Disease-What Stands out in the Current Picture? A Comprehensive Review

Non-coding RNAs (ncRNA) have paved the way to new perspectives on the regulation of gene expression, not only in biology and medicine, but also in associated fields and technologies, ensuring advances in diagnostic means and therapeutic modalities. Critical in this multistep approach are the associations of long non-coding RNA (lncRNA) with diseases and their causal genes in their networks of interactions, gene enrichment and expression analysis, associated pathways, the monitoring of the involved genes and their functional roles during disease progression from one stage to another. Studies have shown that Johne's Disease (JD), caused by Mycobacterium avium subspecies partuberculosis (MAP), shares common lncRNAs, clinical findings, and other molecular entities with Crohn's Disease (CD). This has been a subject of vigorous investigation owing to the zoonotic nature of this condition, although results are still inconclusive. In this review, on one hand, the current knowledge of lncRNAs in cells is presented, focusing on the pathogenesis of gastrointestinal-related pathologies and MAP-related infections and, on the other hand, we attempt to dissect the associated genes and pathways involved. Furthermore, the recently characterized and novel lncRNAs share common pathologies with IBD and JD, including the expression, molecular networks, and dataset analysis results. These are also presented in an attempt to identify potential biomarkers pertinent to cattle and human disease phenotypes.

The Effects of Synbiotics on Dextran-Sodium-Sulfate-Induced Acute Colitis: The Impact of Chitosan Oligosaccharides on Endogenous/Exogenous Lactiplantibacillus plantarum

In this work, Lactiplantibacillus plantarum (L. plantarum) isolated from mice feces (LP-M) and pickles (LP-P) were chosen as the endogenous and exogenous L. plantarum, respectively, which were separately combined with chitosan oligosaccharides (COS) to be synbiotics. The anti-inflammatory activity of LP-M, LP-P, COS, and the synbiotics was explored using dextran-sodium-sulfate (DSS)-induced acute colitis mice, as well as by comparing the synergistic effects of COS with LP-M or LP-P. The results revealed that L. plantarum, COS, and the synbiotics alleviated the symptoms of mice colitis and inhibited the changes in short-chain fatty acids (SCFAs), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, IL-10, and myeloperoxidase (MPO) caused by DSS. In addition, the intervention of L. plantarum, COS, and the synbiotics increased the relative abundance of beneficial bacteria Muribaculaceae and Lactobacillus and suppressed the pathogenic bacteria Turicibacter and Escherichia-Shigella. There was no statistically difference between LP-M and the endogenous synbiotics on intestinal immunity and metabolism. However, the exogenous synbiotics improved SCFAs, inhibited the changes in cytokines and MPO activity, and restored the gut microbiota more effectively than exogenous L. plantarum LP-P. This indicated that the anti-inflammatory activity of exogenous LP-P can be increased by combining it with COS as a synbiotic.

Microplastics perturb colonic epithelial homeostasis associated with intestinal overproliferation, exacerbating the severity of colitis

A great amount of the population died due to living or working in an unhealthy environment, highlighting the critical role of environmental pollutants in inducing diseases. Microplastics are widespread environmental pollutants and have been found in various tissues of human beings, yet the risk of microplastics in the occurrence of disease, especially environmentally-related colitis, is unclear. This study focused on the effects of microplastics exposure on intestinal homeostasis and the initiation of colitis. We noticed that microplastics exposure had a limited impact on mice, as verified by no difference observed in bodyweight change, IL-1β and IL-6 levels in jejunum and liver. Nevertheless, in the colon, the IL-1β and IL-6 levels were slightly increased and the goblet cell number was decreased. Interestingly, we observed that crypt number and depth, the levels of intestinal stem cell markers, combined with the expression of proliferating cell nuclear antigen and proto-oncogene c-Myc were all significantly increased with microplastics treatment, indicating the overproliferation of colonic mucosa. The effect of microplastics on proliferation and differentiation of crypt was further demonstrated to be regulated by the overactivation of the Notch signaling pathway in intestinal organoids. Furthermore, microplastics exposure accelerated the development of colitis with severe bodyweight loss, diarrhea and bloody stools, macroscopic and pathological damage, and inflammation levels. Worsened liver pathological damage and inflammation in mice with colitis under microplastics exposure also were found. These results suggested that microplastics disrupted the balance between colonic epithelium self-renewal and differentiation, exacerbating the colitis, and might be an environmental-related disease risk factor.

Clustering of pediatric onset inflammatory bowel disease in Finland: a nationwide register-based study

BACKGROUND

The incidence of pediatric inflammatory bowel disease (PIBD) has increased dramatically during the past decades. This implies involvement of environmental factors in etiology but lends no clues about specific agents. We evaluated clustering in time and place of residence at PIBD onset using a case-control setting with comprehensive nationwide register data.

METHODS

We included all PIBD cases diagnosed at ages < 18 years during 1992-2017 (3748 cases; median age of 14.6; 2316 (58%) with ulcerative colitis (UC), 1432 with Crohn's, and 18,740 age- and sex-matched controls) and constructed complete residential histories (including coordinates) from the national database until the date of the diagnosis of the case assigned as index date for the controls. Using the coordinates of the addresses of the subjects and the diagnosis/index dates, we evaluated clustering in time and place using the Knox test. Four temporal (2, 4, 6, 12 months) and four distance (0.25, 0.5, 1, 5 km) thresholds were used, and results were calculated separately for Crohn´s disease and UC. Similar analyses were conducted using the addresses at birth and the addresses five years before the diagnosis or index date. Based on the threshold values displaying the most clustering in the Knox test, logistic regression models were built to identify whether sex, age at diagnosis or the year of diagnosis affected the probability of belonging to a cluster. To analyze clustering in time and place throughout the residential histories, we used Jacquez's Q with an open-access python program pyjacqQ.

RESULTS

The mean number of residencies until the index date was 2.91 for cases and 3.05 for controls (p = 0.0003). Knox test indicated residential clustering for UC with thresholds of 500 m between locations and time-period of four months (p = 0.004). In the regression analysis, sex, age at diagnosis or year of UC diagnosis did not show differences between the clustered and other cases. Jacquez Q analyses showed higher than expected frequency of clustered cases throughout residential histories (p < 10^- 8).

CONCLUSION

Our findings suggest that the incidence of PIBD, especially of UC, exhibits clustering in locations of residencies over time. For the clustered cases, environmental triggers warrant future studies.

The role of long noncoding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) in immune diseases

The long noncoding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) has been shown to be involved in the pathogenesis of several diseases. Herein, we discuss recent developments and insights into NEAT1 and its contribution to a variety of immune disorders. Our evaluations revealed that NEAT1's function in immune diseases seems to be focused on the modulation of paraspeckle expression and it is primarily associated with the nuclear retention of its mRNA. NEAT1 is also involved in the sequestration of paraspeckle proteins and in affecting the transcriptional expression of specific immune regulators. The expression of NEAT1 may be aberrantly upregulated in several immune pathologies, indicating that it could serve as a potential prognostic biomarker in these conditions. We summarized describing the expression changes and the role of NEAT1 in several immune diseases. We also described the mechanism of its regulation of the immune cell differentiation and function of NEAT1 in different disease.

Gut community alterations associated with Clostridioides difficile colonization in hospitalized gastroenterological patients with or without inflammatory bowel disease

Clostridioides difficile colonization and development of infection commonly occur in inflammatory bowel disease (IBD) patients and can trigger flare-ups. Both conditions are inherently linked to disrupted gut microbiota. This study included 149 hospitalized gastrointestinal patients, which were divided into IBD (n = 48) and non-IBD patients (n = 101). Patients were tested for C. difficile colonization (qPCR and selective plating), and gut bacterial communities were analyzed with 16S amplicon sequencing. Blood test results were retrospectively collected from the medical records. IBD and non-IBD patients had comparable C. difficile colonization rates (31.7 and 33.3%, respectively). Compared to non-IBD C. difficile-non-colonized patients, IBD and C. difficile-colonized patients shared multiple common bacterial community characteristics including decreased diversity and reduced abundance of strict anaerobic bacteria. Furthermore, certain microbiota alterations were enhanced when IBD was accompanied by C. difficile colonization, indicating a synergistic effect between both medical complications. Conversely, certain microbial patterns were specific to C. difficile colonization, e.g., co-occurrence with Enterococcus, which was most common in IBD patients (81.3%).

Long-term exposure to air pollution and risk of incident inflammatory bowel disease among middle and old aged adults

BACKGROUND

Epidemiological evidence regarding the associations between long-term exposure to air pollution and risk of incident inflammatory bowel disease (IBD) is scant.

OBJECTIVES

We examined the associations of various specific air pollutants with the risk of incident ulcerative colitis and Crohn's disease, two subtypes of IBD, among middle and old aged adults in the UK. We also explored potential susceptible subgroups.

METHODS

We used data from the UK Biobank study. Information on air pollution, including PM_2.5, PM_2.5-10, PM₁₀ as well as NO₂ and NO_x were estimated using the Land Use Regression model. Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

After a median follow-up of 11.7 years, 1872 incident ulcerative colitis and 865 incident Crohn's disease cases were identified among 455,210 IBD-free participants. HRs (95% CIs) of ulcerative colitis associated with each 1 interquartile range (IQR) increase in PM_2.5, PM_2.5-10, PM₁₀, NO₂, and NO_x were 1.06 (1.01, 1.12), 1.03 (0.99, 1.08), 1.09 (1.03, 1.16), 1.12 (1.07, 1.19), and 1.07 (1.02, 1.12), respectively. The associations between all the air pollutants and risk of Crohn's disease were null. Smoking status and sex appeared to respectively modify the associations between some air pollutants and risk of ulcerative colitis and Crohn's disease.

CONCLUSION

Long-term exposure to various air pollutants was associated with the risk of incident ulcerative colitis but not Crohn's disease, highlighting the importance of developing environmental health strategy to reduce the burden of ulcerative colitis.

Role of the Gut–Brain Axis, Gut Microbial Composition, Diet, and Probiotic Intervention in Parkinson’s Disease

Parkinson’s disease (PD) is the second-most prevalent neurodegenerative or neuropsychiatric disease, affecting 1% of seniors worldwide. The gut microbiota (GM) is one of the key access controls for most diseases and disorders. Disturbance in the GM creates an imbalance in the function and circulation of metabolites, resulting in unhealthy conditions. Any dysbiosis could affect the function of the gut, consequently disturbing the equilibrium in the intestine, and provoking pro-inflammatory conditions in the gut lumen, which send signals to the central nervous system (CNS) through the vagus enteric nervous system, possibly disturbing the blood–brain barrier. The neuroinflammatory conditions in the brain cause accumulation of α-syn, and progressively develop PD. An important aspect of understanding and treating the disease is access to broad knowledge about the influence of dietary supplements on GM. Probiotics are live microorganisms which, when administered in adequate amounts, confer a health benefit on the host. Probiotic supplementation improves the function of the CNS, and improves the motor and non-motor symptoms of PD. Probiotic supplementation could be an adjuvant therapeutic method to manage PD. This review summarizes the role of GM in health, the GM–brain axis, the pathogenesis of PD, the role of GM and diet in PD, and the influence of probiotic supplementation on PD. The study encourages further detailed clinical trials in PD patients with probiotics, which aids in determining the involvement of GM, intestinal mediators, and neurological mediators in the treatment or management of PD.

Bench to bedside - new insights into the pathogenesis of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the leading cause of death and disability from gastrointestinal disease in premature infants. Recent discoveries have shed light on a unifying theorem to explain the pathogenesis of NEC, suggesting that specific treatments might finally be forthcoming. A variety of experiments have highlighted how the interaction between bacterial signalling receptors on the premature intestine and an abnormal gut microbiota incites a pro-inflammatory response in the intestinal mucosa and its underlying endothelium that leads to NEC. Central amongst the bacterial signalling receptors implicated in NEC development is the lipopolysaccharide receptor Toll-like receptor 4 (TLR4), which is expressed at higher levels in the premature gut than in the full-term gut. The high prenatal intestinal expression of TLR4 reflects the role of TLR4 in the regulation of normal gut development, and supports additional studies indicating that NEC develops in response to signalling events that occur in utero. This Review provides new evidence explaining the pathogenesis of NEC, explores new findings indicating that NEC development has origins before birth, and discusses future questions and opportunities for discovery in this field.

Inverse and Concordant Mucosal Pathway Gene Expressions in Inflamed and Non-Inflamed Ulcerative Colitis Patients: Potential Relevance to Aetiology and Pathogenesis

Ulcerative colitis (UC) arises from a complex interplay between host and environmental factors, but with a largely unsolved pathophysiology. The pathophysiology was outlined by RNA-sequencing of mucosal biopsies from non-inflamed and inflamed colon of UC patients (14 and 17, respectively), and from 27 patients without intestinal inflammation. Genes differentially expressed (DE), or present in enriched gene sets, were investigated using statistical text analysis of functional protein information. Compared with controls, inflamed and non-inflamed UC mucosa displayed 9360 and 52 DE genes, respectively. Seventy-three non-pseudogenes were DE relative to both gender and inflammation. Mitochondrial processes were downregulated in inflamed and upregulated in non-inflamed UC mucosa, whereas angiogenesis and endoplasmic reticulum (ER) stress were upregulated in both tissue states. Immune responses were upregulated in inflamed mucosa, whereas the non-inflamed UC mucosa presented both up- and downregulated gene sets. DE and enriched genes overlapped with genes present in inflammatory bowel disease genome-wide associated loci (p = 1.43 × 10⁻¹⁸), especially regarding immune responses, respiratory chain, angiogenesis, ER stress, and steroid hormone metabolism. Apart from confirming established pathophysiological mechanisms of immune cells, our study provides evidence for involvement of less described pathways (e.g., respiratory chain, ER stress, fatty-acid oxidation, steroid hormone metabolism and angiogenesis).

In vitro models and ex vivo systems used in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic, relapsing gastrointestinal condition. Ulcerative colitis and Crohn’s disease are types of inflammatory bowel disease. Over many decades, the disease has been a topic of study, with experts still trying to figure out its cause and pathology. Researchers have established many in vivo animal models, in vitro cell lines, and ex vivo systems to understand its cause ultimately and adequately identify a therapy. However, in vivo animal models cannot be regarded as good models for studying IBD since they cannot completely simulate the disease. Furthermore, because species differences are a crucial subject of concern, in vitro cell lines and ex vivo systems can be employed to recreate the condition properly. In vitro models serve as the starting point for biological and medical research. Ex vivo and in vitro models for replicating gut physiology have been developed. This review aims to present a clear understanding of several in vitro and ex vivo models of IBD and provide insights into their benefits and limits and their value in understanding intestinal physiology.

Trends in the use of biologicals and their treatment outcomes among patients with inflammatory bowel diseases - a Danish nationwide cohort study

BACKGROUND

Therapeutic management of inflammatory bowel diseases (IBD) is rapidly evolving, with an expanding armoury of biological drugs at our disposal. However, real-world findings about treatment persistence and the impact of biologicals on surgery remain inconsistent.

AIMS

This study aimed to investigate trends in biological use and surgery rates in a nationwide cohort of biological-naïve IBD patients.

METHODS

Patients with IBD who initiated biological treatment between 2011 and 2018 were identified in the Danish National Patient Registry. Data on use of biologicals, surgeries and healthcare costs were retrieved and analysed for time trends.

RESULTS

Between 2011 and 2018, a total of 6,036 IBD (51% ulcerative colitis (UC), 49% Crohn's disease (CD)) patients received biological treatment for the first time. Cumulative use of biologicals increased from 5.0% to 10.8% among UC and 8.9%-14.5% among CD patients. Infliximab remained the most-prescribed first-line biological for UC and CD. Treatment persistence was 44.3% and 16.9% after 1 and 3 years in UC, compared to 59.9% and 33.6% in CD patients. Overall, 32.8% of patients switched to a second biological. Surgery rates decreased in both UC (P = 0.015) and CD (P = 0.008) patients and remained significant for UC in the Cox regression model (P = 0.002). Outpatient and surgical costs also fell among both UC and CD patients.

CONCLUSIONS

Persistence rates for first-line biologicals among IBD patients were low and one-third switched treatment. Surgery rates and direct costs decreased over time, but whether this is related to the use of biologicals has yet to be determined.

Polystyrene microplastics induce an immunometabolic active state in macrophages

Anti-inflammatory and proinflammatory responses in macrophages are influenced by cellular metabolism. Macrophages are the primary phagocyte in mucosal environments (i.e., intestinal tract and lungs) acting as first-line defense against microorganisms and environmental pollutants. Given the extensive contamination of our food and water sources with microplastics, we aimed to examine the metabolic response in macrophages to microplastic particles (MPs). Utilizing murine macrophages, we assessed the metabolic response of macrophages after polystyrene MP phagocytosis. The phagocytosis of MP by macrophages induced a metabolic shift toward glycolysis and a reduction in mitochondrial respiration that was associated with an increase of cell surface markers CD80 and CD86 and cytokine gene expression associated with glycolysis. The gastrointestinal consequences of this metabolic switch in the context of an immune response remain uncertain, but the global rise of plastic pollution and MP ingestion potentially poses an unappreciated health risk. Macrophage phagocytosis of microplastics alters cellular metabolism. - Macrophages cannot degrade PS MP. - MP phagocytosis increases glycolysis in murine macrophages. - MP phagocytosis reduces mitochondrial respiration in murine macrophages.

The Role of T Follicular Helper Cells and Interleukin-21 in the Pathogenesis of Inflammatory Bowel Disease

T follicular helper (Tfh) cells represent a novel subset of CD4⁺ T cells which can provide critical help for germinal center (GC) formation and antibody production. The Tfh cells are characterized by the expression of CXC chemokine receptor 5 (CXCR5), programmed death 1 (PD-1), inducible costimulatory molecule (ICOS), B cell lymphoma 6 (BCL-6), and the secretion of interleukin-21 (IL-21). Given the important role of Tfh cells in B cell activation and high-affinity antibody production, Tfh cells are involved in the pathogenesis of many human diseases. Inflammatory bowel disease (IBD) is a group of chronic inflammatory diseases characterized by symptoms such as diarrhea, abdominal pain, and weight loss. Ulcerative colitis (UC) and Crohn's disease (CD) are the most studied types of IBD. Dysregulated mucosal immune response plays an important role in the pathogenesis of IBD. In recent years, many studies have identified the critical role of Tfh cells and IL-21 in the pathogenic process IBD. In this paper, we will discuss the role of Tfh cells and IL-21 in IBD pathogenesis.

Curcumin and Its Modified Formulations on Inflammatory Bowel Disease (IBD): The Story So Far and Future Outlook

Inflammatory bowel disease (IBD) is a chronic relapsing and remitting inflammatory disorder of the small intestine and colon. IBD includes ulcerative colitis (UC) and Crohn's disease (CD), and it is a major factor for the development of colon cancer, referred to as colitis-associated cancer (CAC). The current treatment of IBD mainly includes the use of synthetic drugs and monoclonal antibodies. However, these drugs have side effects over long-term use, and the high relapse rate restricts their application. In the recent past, many studies had witnessed a surge in applying plant-derived products to manage various diseases, including IBD. Curcumin is a bioactive component derived from a rhizome of turmeric (Curcuma longa). Numerous in vitro and in vivo studies show that curcumin may interact with many cellular targets (NF-κB, JAKs/STATs, MAPKs, TNF-γ, IL-6, PPARγ, and TRPV1) and effectively reduce the progression of IBD with promising results. Thus, curcumin is a potential therapeutic agent for patients with IBD once it significantly decreases clinical relapse in patients with quiescent IBD. This review aims to summarize recent advances and provide a comprehensive picture of curcumin's effectiveness in IBD and offer our view on future research on curcumin in IBD treatment.

Tofacitinib inhibits inflammatory cytokines from ulcerative colitis and healthy mucosal explants and is associated with pSTAT1/3 reduction in T-cells

Poor translatability of animal disease models has hampered the development of new inflammatory bowel disorder (IBD) therapeutics. We describe a preclinical, ex vivo system using freshly obtained and well-characterized human colorectal tissue from patients with ulcerative colitis (UC) and healthy control (HC) participants to test potential therapeutics for efficacy and target engagement, using the JAK/STAT inhibitor tofacitinib (TOFA) as a model therapeutic. Colorectal biopsies from HC participants and patients with UC were cultured and stimulated with multiple mitogens ± TOFA. Soluble biomarkers were detected using a 29-analyte multiplex ELISA. Target engagement in CD3⁺CD4⁺ and CD3⁺CD8⁺ T-cells was determined by flow cytometry in peripheral blood mononuclear cells (PBMCs) and isolated mucosal mononuclear cells (MMCs) following the activation of STAT1/3 phosphorylation. Data were analyzed using linear mixed-effects modeling, t test, and analysis of variance. Biomarker selection was performed using penalized and Bayesian logistic regression modeling, with results visualized using uniform manifold approximation and projection. Under baseline conditions, 27 of 29 biomarkers from patients with UC were increased versus HC participants. Explant stimulation increased biomarker release magnitude, expanding the dynamic range for efficacy and target engagement studies. Logistic regression analyses identified the most representative UC baseline and stimulated biomarkers. TOFA inhibited biomarkers dependent on JAK/STAT signaling. STAT1/3 phosphorylation in T-cells revealed compartmental differences between PBMCs and MMCs. Immunogen stimulation increases biomarker release in similar patterns for HC participants and patients with UC, while enhancing the dynamic range for pharmacological effects. This work demonstrates the power of ex vivo human colorectal tissue as preclinical tools for evaluating target engagement and downstream effects of new IBD therapeutic agents.NEW & NOTEWORTHY Using colorectal biopsy material from healthy volunteers and patients with clinically defined IBD supports translational research by informing the evaluation of therapeutic efficacy and target engagement for the development of new therapeutic entities. Combining experimental readouts from intact and dissociated tissue enhances our understanding of the tissue-resident immune system that contribute to disease pathology. Bayesian logistic regression modeling is an effective tool for predicting ex vivo explant biomarker release patterns.

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.

Sphingosine-1-phosphate signal transducer and activator of transcription 3 signaling pathway contributes to baicalein-mediated inhibition of dextran sulfate sodium-induced experimental colitis in mice

Background:

Baicalein has been shown to have anti-inflammatory and anti-tumor activities. However, the mechanisms underlying its anti-inflammatory effect on colitis remain unclear.

Methods:

A dextran sodium sulfate (DSS)-induced model of acute colitis was established in BALB/c mice (6–8 weeks old, weighing 18–22 g). Six groups of mice received: (1) water for 10 days (control), n = 6; (2) DSS 4% solution in the drinking water for 7 days, followed by normal water for 3 days, n = 7; (3), (4), and (5) as for group 2 plus baicalein (10, 20, 40 mg/kg) administered once daily starting on day 1, n = 6; and (6) as for (2) plus 5-aminosalicylic acid (50 mg/kg) administered once daily starting on day 1, n = 6. Body weights, stool consistency, and hematochezia were recorded, and the severity of colitis was evaluated using a disease activity index. On day 11, the mice were euthanized, and organs and blood were collected for analysis. Serum inflammatory factors were detected by enzyme-linked immunosorbent assay; CD11b-positive cells were analyzed by immunofluorescence microscopy; expression of retinoic-acid-receptor-related orphan nuclear receptor gamma, sphingosine kinase 1 (SPHK1), and phosphorylated signal transducer and activator of transcription 3 (p-STAT3) was detected by immunohistochemistry; and expression of nucleotide-binding oligomerization domain 2 (NOD2), SPHK1, sphingosine 1-phosphate receptor 1 (S1PR1), total STAT3, and p-STAT3 were detected by western blotting analysis. Inter-group differences were compared using Student's t test.

Results:

Baicalein treatment dose-dependently reduced DSS-induced weight loss (P < 0.01 or P < 0.05), splenomegaly (P < 0.01), and colonic damage, as reflected by amelioration of diarrhea, rectal bleeding, and colonic ulceration, congestion, edema (shown as colon length, P < 0.05 or P < 0.01), and inflammatory cell infiltration. Baicalein also significantly decreased the levels of inflammatory mediators in the serum (P < 0.01) and colon, and significantly inhibited expression of NOD2 SPHK1, S1PR1, and p-STAT3 in the colon (P < 0.05).

Conclusions:

Baicalein treatment ameliorated colitis in mice by inhibiting S1P-STAT3 signaling, suggesting that this flavonoid might be beneficial in the treatment of colitis.

Identification and diagnosis of Crohn disease and ulcerative colitis in children

Crohn disease and ulcerative colitis are the two main types of inflammatory bowel disease. High rates of these conditions are seen in Australasian children - furthermore, increasing rates have been evident in recent years. Children can present with typical symptoms of abdominal pain, diarrhoea, haematochezia and/or weight loss. Atypical presentations (such as skin lesions or isolated short stature) can also occur: these may be associated with delays in the consideration and diagnosis of IBD. Initial steps in establishing a diagnosis of IBD include delineation of inflammatory markers exclusion of any other likely aetiology. Definitive diagnosis relies upon key endoscopic, histologic and radiological findings. Overall management of IBD encompasses care within a team-based, child and family-focused, multi-disciplinary setting.

Mapping global research trends in stem cell therapy for inflammatory bowel disease: a bibliometric analysis from 1991 to 2019

BACKGROUND

Inflammatory bowel disease (IBD) represents a series of digestive system abnormalities and parenteral manifestations. Stem cell therapy has been regarded as a promising treatment for IBD.

METHODS

We searched Web of Science Core Collection for publications of interest from 1991 to 2019. Publication performance was analyzed using several bibliometric parameters, including Statplanet to reveal the geographic distribution of the publications, VOSviewer to identify the research landscape of hot topics, and CiteSpace to show keywords with the strongest citation bursts.

RESULTS

A total of 1230 publications were identified, of which 674 articles were analyzed further. The United States was the most productive country and Spanish researchers published the highest quality articles. At a journal level, Gastroenterology published the greatest number of articles, while articles from Gut had the highest citation number. Results from the research landscape analysis of hot topics and the top 20 terms with the strongest citation bursts indicated that animal experiments, immunocytes, intestinal epithelial cells, cytokine expression, and clinical efficacy were the main focuses of research.

CONCLUSION

Stem cell therapy for IBD is currently receiving increasing attention by researchers, with focuses on animal experiments, immunocytes, intestinal epithelial cells, cytokine expression, and clinical efficacy.

Which long noncoding RNAs and circular RNAs contribute to inflammatory bowel disease?

Inflammatory bowel disease (IBD), a chronic relapsing gastrointestinal inflammatory disease, mainly comprises ulcerative colitis (UC) and Crohn’s disease (CD). Although the mechanisms and pathways of IBD have been widely examined in recent decades, its exact pathogenesis remains unclear. Studies have focused on the discovery of new therapeutic targets and application of precision medicine. Recently, a strong connection between IBD and noncoding RNAs (ncRNAs) has been reported. ncRNAs include microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs). The contributions of lncRNAs and circRNAs in IBD are less well-studied compared with those of miRNAs. However, lncRNAs and circRNAs are likely to drive personalized therapy for IBD. They will enable accurate diagnosis, prognosis, and prediction of therapeutic responses and promote IBD therapy. Herein, we briefly describe the molecular functions of lncRNAs and circRNAs and provide an overview of the current knowledge of the altered expression profiles of lncRNAs and circRNAs in patients with IBD. Further, we discuss how these RNAs are involved in the nosogenesis of IBD and are emerging as biomarkers.

Review article: impact of cigarette smoking on intestinal inflammation-direct and indirect mechanisms

BACKGROUND

The inflammatory bowel diseases, Crohn's disease and ulcerative colitis are related multifactorial diseases. Their pathogenesis is influenced by each individual's immune system, the environmental factors within exposome and genetic predisposition. Smoking habit is the single best-established environmental factor that influences disease phenotype, behaviour and response to therapy.

AIM

To assess current epidemiological, experimental and clinical evidence that may explain how smoking impacts on the pathogenesis of inflammatory bowel disease.

METHODS

A Medline search for 'cigarette smoking', in combination with terms including 'passive', 'second-hand', 'intestinal inflammation', 'Crohn's disease', 'ulcerative colitis', 'colitis'; 'intestinal epithelium', 'immune system', 'intestinal microbiota', 'tight junctions', 'mucus', 'goblet cells', 'Paneth cells', 'autophagy'; 'epigenetics', 'genes', 'DNA methylation', 'histones', 'short noncoding/long noncoding RNAs'; 'carbon monoxide/CO' and 'nitric oxide/NO' was performed.

RESULTS

Studies found evidence of direct and indirect effects of smoking on various parameters, including oxidative damage, impairment of intestinal barrier and immune cell function, epigenetic and microbiota composition changes, that contribute to the pathogenesis of inflammatory bowel disease.

CONCLUSIONS

Cigarette smoking promotes intestinal inflammation by affecting the function and interactions among intestinal epithelium, immune system and microbiota/microbiome.

Correlation between antibiotic use in childhood and subsequent inflammatory bowel disease: a systematic review and meta-analysis

Background: Antibiotic use leads to a cascade of inflammatory reaction in the gastrointestinal tract due to its association with a temporary disruption of human microbiome.Objectives: To explore the undetermined correlation between antibiotic use in childhood and subsequent inflammatory bowel disease (IBD).Methods: PUBMED, EMBASE and Cochrane Central Register of Controlled Trials were searched to identify related articles. We extracted and pooled the (adjusted) odds ratio (OR) and (adjusted) risk ratio (RR).Results: This systematic review and meta-analysis included 11 studies. The pooled OR of all 11 studies was 1.5 (95% confidence interval (CI): 1.22-1.85). The pooled ORs of the subsequent Crohn's disease and ulcerative colitis after antibiotic use in childhood were 1.59 (95% CI: 1.06-2.4) and 1.22 (95% CI: 0.82-1.8). The sensitivity analysis showed no change. The meta-regression showed there was not statistical significance for the publication year, research area and research methods. Egger's test showed publication bias in the IBD studies (p  =  .006  <  .05) but no publication bias for the CD (p  =  .275>.05) and UC studies (p  =  .537>.05).Conclusions: There was a positive association between antibiotic use in childhood and the subsequently risk of Crohn's disease in non-European countries in the west during 2010-2013. Children in the United States taking antibiotics will have a higher risk of subsequently IBD than Europe, Asia and Australia. Registration number: CRD42019147648 (PROSPERO).

Predictors of response and disease course in patients with inflammatory bowel disease treated with biological therapy-the Danish IBD Biobank Project: protocol for a multicentre prospective cohort study

INTRODUCTION

Inflammatory bowel diseases (IBDs) are chronic diseases of unknown cause characterised by a progressive and unpredictable disease course. In the last decade, biological treatment has become a cornerstone in the treatment of IBD. However, one-in-three-to-four patients do not respond to first-line biological agents and another third of patients see their response diminish over time. This highlights an unmet need for optimising the use of biologicals and the prediction of treatment response. Considering the multifaceted nature of IBD, we hypothesise that multiomics profiling of sequential samples from single patients could facilitate the discovery of predictive biomarkers of response to biological therapy and disease course.

METHODS

This is a multicentre prospective cohort study which will enrol 840 biological-naïve patients with IBD who initiate biological therapy in a 3-year period. Primary outcomes are the occurrence of primary non-response (evaluated at weeks 14-16) and loss of response (evaluated during entire follow-up in patients who obtain partial or full response after induction period). Each patient will be followed up for their clinical data for at least 1 year or till the end of study period (up to 4 years). Blood and stool samples will be collected sequentially during the first year of biological treatment. Intestinal tissue will be sampled after 1 year of treatment and whenever an endoscopy is performed. Samples will undergo transcriptomic, proteomic and microbial DNA analyses. Omics data will be integrated with clinical data to identify a panel of predictive biomarkers of response to biological therapy and disease behaviour in patients with IBD.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Danish Ethics Committee (H-18064178). Inclusion is ongoing at three study centres and will be initiated in two additional centres. Both positive and negative study results will be disseminated through peer-reviewed journals according to Strengthening the Reporting of Observational Studies in Epidemiology guidelines, as well as presented at international conferences.

Viewpoint: Inflammatory Bowel Diseases Among Immigrants From Low- to High-Incidence Countries: Opportunities and Considerations

The inflammatory bowel diseases [IBDs], inclusive of Crohn's disease [CD] and ulcerative colitis [UC], are chronic, progressive immune-mediated diseases associated with high morbidity and substantial economic impact. The pathogenesis implicates a complex interaction between environmental determinants and genetic susceptibility. Of concern, the incidence and prevalence of IBD are increasing globally, with the highest relative increase observed in developing and recently developed countries. One high-risk yet underappreciated population is immigrants from countries of low to high IBD incidence, as evidenced by epidemiologic studies demonstrating higher risk of IBD among second- versus first-generation and younger versus older immigrants from low- to high-incidence countries [LTHICs]. The reasons underlying these emerging patterns among immigrants are incompletely understood and provide enormous opportunities to better define the pathophysiology of IBD and move toward disease prevention or at least earlier diagnosis. The rapidity of this epidemiologic shift in the demographic profile of IBD, which was traditionally a disease of Caucasians in industrialized countries, strongly implicates non-genetic factors and gene-environment interactions in the pathophysiology of IBD among immigrants from LTHICs. The primary objectives of this Viewpoint are to [1] provide a focused overview of IBD epidemiology among immigrants from countries at differential IBD risk; [2] emphasize the potential to advance our understanding of IBD pathogenesis via targeted research efforts to delineate risk and protective determinants in this cohort; and [3] highlight disparities and barriers in IBD care, as well as the economic implications of the rising, yet underappreciated, disease burden among immigrants from LTHICs.

Precision medicine in inflammatory bowel disease: concept, progress and challenges

Crohn's disease and ulcerative colitis are increasingly prevalent, relapsing and remitting inflammatory bowel diseases (IBDs) with variable disease courses and complications. Their aetiology remains unclear but current evidence shows an increasingly complex pathophysiology broadly centring on the genome, exposome, microbiome and immunome. Our increased understanding of disease pathogenesis is providing an ever-expanding arsenal of therapeutic options, but these can be expensive and patients can lose response or never respond to certain therapies. Therefore, there is now a growing need to personalise therapies on the basis of the underlying disease biology and a desire to shift our approach from "reactive" management driven by disease complications to "proactive" care with an aim to prevent disease sequelae. Precision medicine is the tailoring of medical treatment to the individual patient, encompassing a multitude of data-driven (and multi-omic) approaches to foster accurate clinical decision-making. In IBD, precision medicine would have significant benefits, enabling timely therapy that is both effective and appropriate for the individual. In this review, we summarise some of the key areas of progress towards precision medicine, including predicting disease susceptibility and its course, personalising therapies in IBD and monitoring response to therapy. We also highlight some of the challenges to be overcome in order to deliver this approach.

History of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are characterized by chronic inflammation of the intestinal mucosa and unknown etiology. In this review, we identified three main eras in the IBD history. Between the 19th and the 20th century, the primary task had been the definition of the diagnostic criteria in order to differentiate the new entity from intestinal tuberculosis. In the 20th century, an intense and prolific therapeutic research prevailed, culminating in the introduction of biological drugs in the clinical setting. Since the beginning of the 21st century, traditional definition criteria have been challenged by holistic criteria in an effort to seek a still unattained cure. Centuries of worldwide efforts on IBD etiology and therapy search have culminated in this novel strategy.

Mannose-binding lectin (MBL) in adult patients with inflammatory bowel disease

Inflammatory bowel disease (IBD) refers to disorders associated with progressive inflammatory processes in the gastrointestinal system. IBD consists of two major forms, Crohn's disease (CD), and ulcerative colitis (UC). IBD became a global disease in the 21^st century. Its pathogenesis is still not fully understood. Mannose-binding lectin (MBL) is a pattern-recognising molecule, involved in anti-microbial and anti-cancer immunity. It is able to opsonize microorganisms and abnormal host cells, and to initiate complement activation. The aim of this study was to investigate possible involvement of MBL in inflammatory bowel disease in adults. Forty persons diagnosed with CD and 28 with ulcerative colitis were recruited. The control group consisted of 136 healthy persons. Single nucleotide polymorphisms of the MBL2 gene (localised to both promoter and exon 1) were determined as were serum MBL concentrations. The exon 1 variant alleles and MBL deficiency-associated genotypes were more frequent among patients compared with controls, although this difference was not statistically significant. No differences of MBL levels were found between the major groups. However in MBL2 A/A homozygous IBD patients, the median was significantly higher than in corresponding healthy subjects. That was particularly evident in the case of active Crohn's disease (1493 ng/ml vs. 800 ng/ml, p = 0.021). It may suggest that MBL and MBL-dependent complement activation contributes to excessive inflammation and its adverse effects in the course of CD. It cannot also be excluded that high MBL activity constitutes in some cases part of a multifactorial network conducing to development of CD.

Inflammatory Bowel Diseases and Parkinson's Disease

The etiology of Parkinson's disease (PD) is multifactorial, with genetics, aging, and environmental agents all a part of the PD pathogenesis. Widespread aggregation of the α-synuclein protein in the form of Lewy bodies and Lewy neurites, and degeneration of substantia nigra dopamine neurons are the pathological hallmarks of PD. Inflammatory responses manifested by glial reactions, T cell infiltration, and increased expression of inflammatory cytokines, as well as other toxic mediators derived from activated glial cells, are currently recognized as prominent features of PD. Experimental, clinical and epidemiological data suggest that intestinal inflammation contributes to the pathogenesis of PD, and the increasing number of studies suggests that the condition may start in the gastrointestinal system years before any motor symptoms develop. Patients with inflammatory bowel disease (IBD) have a higher risk of developing PD compared with non-IBD individuals. Gene association study has found a genetic link between IBD and PD, and an evidence from animal studies suggests that gut inflammation, similar to that observed in IBD, may induce loss of dopaminergic neurons. Based on preclinical models of PD, it is suggested that the enteric microbiome changes early in PD, and gut infections trigger α-synuclein release and aggregation. In this paper, the possible link between IBD and PD is reviewed based on the available literature. Given the potentially critical role of gastrointestinal pathology in PD pathogenesis, there is reason to suspect that IBD or its treatments may impact PD risk. Thus, clinicians should be aware of PD symptoms in IBD patients.