Role of genetics in pediatric inflammatory bowel disease

Serum cytokines MCP-1 and GCS-F as potential biomarkers in pediatric inflammatory bowel disease

BACKGROUND

Inflammatory bowel diseases (IBDs) with the subtypes ulcerative colitis (UC) and Crohn disease (CD), are chronic autoimmune inflammatory disorders of the gastrointestinal tract. Cytokines are associated with the development and progression in pediatric IBD. We measured cytokine levels in pediatric IBD patients to assess their potential function as biomarkers in disease assessment.

METHOD

In this prospective cohort study, we enrolled 33 children with IBD. All patients were in stable remission for 3 months on enrollment. Patients who developed a relapse within six months after enrollment were classified as relapsers. Blood sampling was performed at enrolment and for relapsers in relapse and post-relapse. Serum concentrations of 14 cytokines, chemokines and growth factors (IL-1α, IL-1β, IL-6, IL-12p40, IP-10, TNF-α, IFN-γ, IL-10, IL-8, MIP-1α, MCP-1, MCP-3, G-CSF, GM-CSF) were measured simultaneously using multiplex bead-based sandwich immunoassay on Luminex 100 system.

RESULTS

MCP-1 was significantly higher in CD patients compared to UC patients at each disease stage: stable remission (P<0.048), unstable remission (P<0.013), relapse (P<0.026) and post-relapse (P<0.024). G-CSF was significantly increased in UC patients developing a relapse and in post-relapse stage compared to UC patients in remission (P<0.02 and p<0.03, respectively).

CONCLUSION

MCP-1 showed potential as a diagnostic biomarker in CD patients independent of disease activity as it was able to discriminate between subtypes of pediatric IBD. In UC patients, G-CSF was significantly elevated in relapsers indicating its use and role as a potential prognostic biomarker.

Pediatric Ulcerative Colitis in Siblings

This case report discusses a nine-year-old female that presented with abdominal pain, diarrhea, and weight loss, suggestive of inflammatory bowel disease (IBD). She had an older brother previously diagnosed with ulcerative colitis (UC), which raised suspicion that she may have the same condition. CT scan of the abdomen/pelvis showed signs of bowel thickening. Stool studies revealed elevated inflammatory markers including lactoferrin and calprotectin, as well as occult blood. She underwent a colonoscopy and rectal biopsy which further confirmed the diagnosis of ulcerative colitis. This article aims to discuss the clinical presentation, role of genetic factors, diagnostic workup, and therapeutic management of ulcerative colitis in the pediatric population.

Prognostic Factors of Biologic Therapy in Pediatric IBD

This was a retrospective cohort study aimed at identifying parameters measured at diagnosis of pediatric IBD to predict subsequent biologic therapy, as an equivalent to an unfavorable clinical course. Identification of predictors of poor outcomes is an important issue in current ECCO guidelines on pIBD. The study population consisted of 119 children with Crohn’s disease and 112 with ulcerative colitis, diagnosed and monitored for at least 1 year from 2009–2019. The population was divided into the study groups separately: 39 children with CD and 14 with UC who received biologics before the age of 18 y compared to 80 with CD and 98 with UC who did not. The combined analysis of 53 biologic therapy recipients vs. 178 non-recipients with IBD was also conducted. Logistic regression tests (OR, RR) and sensitivity, specificity, PPV, and NPV were used. Factors significantly correlated with subsequent biologic therapy were perianal disease, complicated disease behavior, high PCDAI (CD), fatigue, hypoalbuminemia, high PUCAI (UC) and fever, fatigue, hypoalbuminemia, hypoproteinemia, and elevated CRP (IBD). Marginally significant factors were ileocecal disease, elevated serum IgA, anemia, and L4a–L4b coexistence. Apart from parameters already accepted as POPO (B2/3, perianal disease), interesting observations are the significance of IgA, L4a–L4b in CD, and hypoalbuminemia in UC.

The Therapeutic Role of Short-Chain Fatty Acids Mediated Very Low-Calorie Ketogenic Diet-Gut Microbiota Relationships in Paediatric Inflammatory Bowel Diseases

The very low-calorie ketogenic diet (VLCKD) has been recognized as a promising dietary regimen for the treatment of several diseases. Short-chain fatty acids (SCFAs) produced by anaerobic bacterial fermentation of indigestible dietary fibre in the gut have potential value for their underlying epigenetic role in the treatment of obesity and asthma-related inflammation through mediating the relationships between VLCKD and the infant gut microbiota. However, it is still unclear how VLCKD might influence gut microbiota composition in children, and how SCFAs could play a role in the treatment of inflammatory bowel disease (IBD). To overcome this knowledge gap, this review aims to investigate the role of SCFAs as key epigenetic metabolites that mediate VLCKD-gut microbiota relationships in children, and their therapeutic potential in IBD.

Clinical Phenotypes and Outcomes in Monogenic Versus Non-monogenic Very Early Onset Inflammatory Bowel Disease

BACKGROUND AND AIMS

Over 80 monogenic causes of very early onset inflammatory bowel disease [VEOIBD] have been identified. Prior reports of the natural history of VEOIBD have not considered monogenic disease status. The objective of this study is to describe clinical phenotypes and outcomes in a large single-centre cohort of patients with VEOIBD and universal access to whole exome sequencing [WES].

METHODS

Patients receiving IBD care at a single centre were prospectively enrolled in a longitudinal data repository starting in 2012. WES was offered with enrollment. Enrolled patients were filtered by age of diagnosis <6 years to comprise a VEOIBD cohort. Monogenic disease was identified by filtering proband variants for rare, loss-of-function, or missense variants in known VEOIBD genes inherited according to standard Mendelian inheritance patterns.

RESULTS

This analysis included 216 VEOIBD patients, followed for a median of 5.8 years. Seventeen patients [7.9%] had monogenic disease. Patients with monogenic IBD were younger at diagnosis and were more likely to have Crohn's disease phenotype with higher rates of stricturing and penetrating disease and extraintestinal manifestations. Patients with monogenic disease were also more likely to experience outcomes of intensive care unit [ICU] hospitalisation, gastrostomy tube, total parenteral nutrition use, stunting at 3-year follow-up, haematopoietic stem cell transplant, and death. A total of 41 patients [19.0%] had infantile-onset disease. After controlling for monogenic disease, patients with infantile-onset IBD did not have increased risk for most severity outcomes.

CONCLUSIONS

Monogenic disease is an important driver of disease severity in VEOIBD. WES is a valuable tool in prognostication and management of VEOIBD.

Polygenic risk and causal inference of psychiatric comorbidity in inflammatory bowel disease among patients with European ancestry

BACKGROUND

Approximately 40% of persons with inflammatory bowel disease (IBD) experience psychiatric comorbidities (PC). Previous studies demonstrated the polygenetic effect on both IBD and PC. In this study, we evaluated the contribution of genetic variants to PC among the IBD population. Additionally, we evaluated whether this effect is mediated by the expression level of the RBPMS gene, which was identified in our previous studies as a potential risk factor of PC in persons with IBD.

MATERIALS AND METHODS

The polygenic risk score (PRS) was estimated among persons with IBD of European ancestry (n = 240) from the Manitoba IBD Cohort Study by using external genome-wide association studies (GWAS). The association and prediction performance were examined between the estimated PRS and PC status among persons with IBD. Finally, regression-based models were applied to explore whether the imputed expression level of the RBPMS gene is a mediator between estimated PRS and PC status in IBD.

RESULTS

The estimated PRS had a significantly positive association with PC status (for the highest effect: P-value threshold = 5 × 10^-3, odds ratio = 2.0, P-value = 1.5 × 10^-5). Around 13% of the causal effect between the PRS and PC status in IBD was mediated by the expression level of the RBPMS gene. The area under the curve of the PRS-based PC prediction model is around 0.7 at the threshold of 5 × 10^-4.

CONCLUSION

PC status in IBD depends on genetic influences among persons with European ancestry. The PRS could potentially be applied to PC risk screening to identify persons with IBD at a high risk of PC. Around 13% of this genetic influence could be explained by the expression level of the RBPMS gene.

Allergic manifestations in autoimmune gastrointestinal disorders

Allergic disorders target a young population, are increasing in both incidence and prevalence and are associated with significant disease burden. They result from the complex interplay between (epi)genetic and environmental factors, resulting in a Th2 inflammatory process targeting the epithelium of the respiratory tract (allergic rhinitis and asthma), skin (atopic dermatitis), and gastrointestinal tract (food allergy). Although the exact pathogenic mechanisms remain elusive, an altered immune system response in the gut is increasingly recognized as a relevant step. Allergic and gastrointestinal autoimmune disorders share several epidemiological, pathogenic and risk factors and several treatment modalities. Here we revise the current literature and show that allergic disorders are highly prevalent in gastrointestinal autoimmune diseases, including celiac disease, inflammatory bowel disease, autoimmune pancreatitis, and autoimmune cholangiopathies. No data are available for some autoimmune diseases, such as autoimmune gastritis and autoimmune enteropathy. To ensure the comprehensive care of patients with autoimmune gastrointestinal disorders, along with disease-specific factors, the presence of allergic disorders should be evaluated and treated when present, possibly targeting shared molecular pathways. Future studies are needed to define the exact pathogenic mechanisms underpinning the association between allergic and autoimmune diseases of the gastrointestinal tract.

Crohn's Disease: Potential Drugs for Modulation of Autophagy

Autophagy is an intracellular process whereby cytoplasmic constituents are degraded within lysosomes. Autophagy functions to eliminate unwanted or damaged materials such as proteins and organelles as their accumulation would be harmful to the cellular system. Autophagy also acts as a defense mechanism against invading pathogens and plays an important role in innate and adaptive immunity. In physiological processes, autophagy is involved in the regulation of tissue development, differentiation and remodeling, which are essential for maintaining cellular homeostasis. Recent studies have demonstrated that autophagy is linked to various diseases and involved in pathophysiological roles, such as adaptation during starvation, anti-aging, antigen presentation, tumor suppression and cell death. The modulation of autophagy has shown greatest promise in Crohn’s disease as most of autophagy drugs involved in these diseases are currently under clinical trials and some has been approved by Food and Drug Administration. This review article discusses autophagy and potential drugs that are currently available for its modulation in Crohn’s disease.

European Society of Paediatric Radiology abdominal imaging task force: statement on imaging in very early onset inflammatory bowel disease

Very early onset inflammatory bowel disease (VEO-IBD) is defined as disease presenting before the age of 6. These children require a tailored imaging approach because conventional imaging studies can be difficult to perform at such a young age. Unlike inflammatory bowel disease in older children and adults, colonic disease predominates in VEO-IBD, and small-bowel disease is rare. Distinguishing Crohn disease from ulcerative colitis is challenging both clinically and on histology. Radiology offers the greatest utility for detecting small-bowel disease because it helps to distinguish the two main disease entities and guide clinical management. Small-bowel ultrasound is recommended as the first-line investigation because it requires relatively little preparation, is readily available and is generally well tolerated in young children. We present these recommendations, based on the current evidence for radiologic management in this group, and propose an imaging algorithm for investigating VEO-IBD.

Study of disease phenotype and its association with prognosis of paediatric inflammatory bowel disease in China

Background

To investigate the unique features of inflammatory bowel disease (IBD) in children, we wanted to identify whether there might be a strong correlation between the disease phenotype and its prognosis at various ages in paediatric patients.

Methods

We collected data from patients diagnosed with IBD (ulcerative colitis (UC) or Crohn’s disease (CD)) from 2002 to 2016. The diagnosis was made according to the Porto criteria and Paris Classification. Patient characteristics, clinical manifestations and treatments were collected. Risk factors for surgery, mortality and relapse were analysed by Cox proportional hazard models.

Results

Of the 143 patients, 113 had CD, and 30 had UC; there were 89 males and 54 females with a median age of 9 years (y). Thirteen patients in the 0–2 y group were identified as having mutations in IL-10 receptor A, and this mutation was significantly more common in this age group than in 3–9 and 10–16 y patients. The risk factor for surgery was the B3 phenotype; risk factors for death were age 0–2 y and B3 phenotype; 0–2 y, B3 phenotype and steroid dependency were risk factors for early relapse.

Conclusions

Clinical manifestations of the onset of IBD in infants and toddlers were extensive and aggressive and were closely associated with early relapse and death. It is of particular interest that some of these patients developed IBD due to monogenic disorders; thus, introduction of genetic testing is essential for these patients.

Pediatric Crohn's Disease in Bahrain

OBJECTIVES

Our study aimed to report the epidemiology, clinical presentations, diagnostic and therapeutic approaches, and outcomes of Crohn's disease (CD) in pediatric patients in Bahrain.

METHODS

We conducted a retrospective review of the medical records of patients with CD diagnosed in the pediatric department, Salmaniya Medical Complex, Bahrain, between 1984 and 2017. We used the data to calculate the annual incidence and cumulative prevalence. Data about gender, nationality, clinical presentation, age at presentation and diagnosis, duration of illness, consanguinity, family history, contact with smokers, and comorbidities were gathered. Results of hematological, biochemical, and serological tests were also collected. All radiological, endoscopic, and histopathological findings were reviewed. Data about medical therapy, relapse episodes, hospital admissions, complications, and outcomes were collected.

RESULTS

Of 108 pediatric patients diagnosed with inflammatory bowel disease (IBD), 51 (47.2%) patients had CD. The annual incidence was 1 in 100 000 per year (range = 0-5 patients/year) with significant rise on comparing the three decades (p = 0.0001). Prevalence was 9.32 patients per 100 000 pediatric populations. Thirty-four patients (66.7%) were males, and the median age was 18.5 years (range = 6.4-35.0). Common clinical presentations were recurrent abdominal pain and weight loss. Family history of IBD was found in 10 patients. One patient had positive antineutrophil cytoplasmic antibody. The terminal ileum was involved in 68.1%, colon in 63.8%, and perianal area in 17.0% patients. Biological therapy was used in five patients. Surgical intervention was required in six patients. The mean follow-up period was 9.2±5.6 years.

CONCLUSIONS

The clinical characteristics of our population are comparable to that reported in neighboring countries and worldwide.

Asthma Is Associated With Subsequent Development of Inflammatory Bowel Disease: A Population-based Case-Control Study

BACKGROUND & AIMS

Asthma and the inflammatory bowel diseases (IBD) each arise through complex interactions between genetic and environmental factors, and share many environmental risk factors. We examined the association between asthma and Crohn's disease or ulcerative colitis.

METHODS

We performed a population-based case-control study using health administrative data from the province of Alberta, Canada. The odds of a diagnosis of asthma preceding the diagnosis of either Crohn's disease (N = 3087) or ulcerative colitis (N = 2377) were compared with the odds of diagnosis of asthma among persons without IBD (N = 402,800) using logistic regression. Effect measure modification by age at diagnosis of IBD (16 years or less, 17-40 years, or older than 40 years) was tested using a likelihood ratio test.

RESULTS

A diagnosis of asthma was associated with increased odds of incident Crohn's disease (adjusted odds ratio [OR], 1.45; 95% confidence interval [CI], 1.31-1.60). No effect measure modification was observed for age at diagnosis for Crohn's disease (P = .42). However, we observed effect measure modification by age at diagnosis for ulcerative colitis (P = .0103), with an adjusted OR of 1.49 (95% CI, 1.08-2.07) among individuals diagnosed at an age of 16 years or less (OR) and an adjusted OR of 1.57 (95% CI, 1.31-1.89) among individuals diagnosed at an age older than 40 years. However, there was no association between asthma and ulcerative colitis among individuals diagnosed between ages 17 and 40 (adjusted OR, 1.05; 95% CI, 0.86-1.26).

CONCLUSIONS

In a population-based case-control study, we associated asthma with Crohn's disease, and with early and late-onset ulcerative colitis.

Susceptibility to Ulcerative Colitis and Genetic Polymorphisms of A251G SOD1 and C-262T CAT

BACKGROUND

Reactive oxygen species can attack and damage almost every molecule found in living cells, including proteins, carbohydrates, lipids, and DNA. For this reason, their production is normally tightly controlled. Among the most important defenses against these radicals are the superoxide dismutase (SOD) enzymes and catalase (CAT). Increasing attention has been given to the role of reactive oxygen metabolites in the pathogenesis of ulcerative colitis (UC), which is defined as an idiopathic and chronic intestinal inflammation. Accordingly, we hypothesized a relation between genetic polymorphisms in the two antioxidant enzymes SOD1 A251G (rs2070424) and CAT C-262T (rs1001179) and the risk of UC.

METHODS

The present case-control study included 109 UC patients (46 males and 50 females) and 186 (67 males and 119 females) gender-matched healthy controls. Genotyping was done by the PCR-RFLP method.

RESULTS

After adjusting for age and gender, a significant association was observed between the AG+GG genotypes of SOD1 A251G polymorphism (vs. AA genotype) and risk of UC (OR=0.29, 95% CI: 0.10-0.86, P= 0.025) after adjusting for age and gender. Our statistical analysis revealed that the CAT C-262T polymorphism did not associate with the risk of UC before and/or after adjusting for age and gender.

CONCLUSIONS

Based on the present statistical analysis, the G allele of the SOD1 A251G polymorphism decreases the risk of UC, thus it might be assumed that the G allele has a protective role.

Microbiome, Metabolome and Inflammatory Bowel Disease

Inflammatory Bowel Disease (IBD) is a multifactorial disorder that conceptually occurs as a result of altered immune responses to commensal and/or pathogenic gut microbes in individuals most susceptible to the disease. During Crohn’s Disease (CD) or Ulcerative Colitis (UC), two components of the human IBD, distinct stages define the disease onset, severity, progression and remission. Epigenetic, environmental (microbiome, metabolome) and nutritional factors are important in IBD pathogenesis. While the dysbiotic microbiota has been proposed to play a role in disease pathogenesis, the data on IBD and diet are still less convincing. Nonetheless, studies are ongoing to examine the effect of pre/probiotics and/or FODMAP reduced diets on both the gut microbiome and its metabolome in an effort to define the healthy diet in patients with IBD. Knowledge of a unique metabolomic fingerprint in IBD could be useful for diagnosis, treatment and detection of disease pathogenesis.

From Genes to Mechanisms: The Expanding Spectrum of Monogenic Disorders Associated with Inflammatory Bowel Disease

Inborn errors of the intestinal epithelial barrier function as well as the innate and adaptive mucosal immune responses toward the intestinal microbiota are a group of genetic disorders that confer susceptibility to monogenic and syndromal forms of inflammatory bowel disease (IBD). There is a continuous spectrum of genetic susceptibility from monogenic causative variants with complete Mendelian inheritance, over NOD2 variants with moderate penetrance to minute penetrance in most common susceptibility variants predisposing to conventional polygenic IBD. We discuss advances to understand monogenic IBD and review recently identified genetic defects. We describe an integrative model for genetic susceptibility variants of conventional IBD and monogenic IBD-like intestinal inflammation in the context of microbial commensal colonization and infection susceptibility.

Microbiota in Inflammatory Bowel Disease Pathogenesis and Therapy: Is It All About Diet?

Inflammatory bowel disease (IBD), including ulcerative colitis, Crohn's disease, and unclassified IBD, continues to cause significant morbidity. While its incidence is increasing, no clear etiology and no cure have yet been discovered. Recent findings suggest that IBD may have a multifactorial etiology, where complex interactions between genetics, epigenetics, environmental factors (including diet but also infections, antibiotics, and sanitation), and host immune system lead to abnormal immune responses and chronic inflammation. Over the past years, the role of altered gut microbiota (in both composition and function) in IBD pathogenesis has emerged as an outstanding area of interest. According to new findings, gut dysbiosis may appear as a key element in initiation of inflammation in IBD and its complications. Moreover, complex metagenomic studies provide possibilities to distinguish between IBD types and appreciate severity and prognosis of the disease, as well as response to therapy. This review provides an updated knowledge of recent findings linking altered bacterial composition and functions, viruses, and fungi to IBD pathogenesis. It also highlights the complex genetic, epigenetic, immune, and microbial interactions in relation to environmental factors (including diet). We overview the actual options to manipulate the altered microbiota, such as modified diet, probiotics, prebiotics, synbiotics, antibiotics, and fecal transplantation. Future possible therapies are also included. Targeting altered microbiota could be the next therapeutic personalized approach, but more research and well-designed comparative prospective studies are required to formulate adequate directions for prevention and therapy.

Current issues of pediatric inflammatory bowel disease in Korea

Inflammatory bowel disease (IBD) is a chronic relapsing disorder of unknown etiology, which is believed to be multifactorial. Recently, the incidence of pediatric IBD has steeply increased in Korea since 2000. Poorly controlled disease activity can result in complications such as intestinal fistulae, abscess, and stricture, as well as growth retardation and delayed puberty in children. Because of a lack of confirmative tests, various diagnostic modalities must be used to diagnose IBD. Onset age, location, behavior, and activity are important in selecting treatments. Monogenic IBD must be excluded among infantile and refractory very-early-onset IBD. Early aggressive therapy using biologics has recently been proposed for peripubertal children to prevent growth failure and malnutrition.