Serum uric acid, body mass index, and cardiovascular diseases: A multiple two-step Mendelian randomization study

BACKGROUND AND AIMS

A number of health issues, including high serum uric acid (SUA) and cardiovascular disease (CVD), have been linked to obesity based on observational evidence, though it's currently unclear how these issues are causally related. In order to determine whether obesity mediates this association, we set out to investigate the causal relationship between SUA, obesity, and CVD.

METHODS AND RESULTS

From publicly available genome-wide association studies, we acquired instrumental variables that had a strong correlation to SUA and body mass index (BMI). We employed multiple two-step Mendelian randomization (MR) analyses, using genetic and clinical data from various publicly available biological databases. The mediating role of BMI was examined through mediation analysis. SUA was genetically correlated with BMI [OR = 1.080, 95% CI: 1.024-1.139, P = 0.005]. There was a positive causal effect of SUA on AF [OR = 0.892, 95% CI: 0.804-0.990, P = 0.032], CAD [OR = 0.942, 95% CI: 0.890-0.997, P = 0.037], and EHT [OR = 1.080, 95% CI: 1.024-1.139, P = 0.005]. Among them, BMI mediated the effects of SUA on AF (42.2%; 95% CI, 35.3%-51.9%), CAD (76.3%; 95% CI, 63.4%-92.0%), and EHT (10.0%; 95% CI, 0%-20.0%).

CONCLUSION

Our research revealed a causal relationship between high SUA exposure and an increased risk of obesity. Additionally, a high SUA level was linked to an increased risk of various CVDs. Given that individuals with high SUA are more likely to be susceptible to AF, CAD, and EHT, attention must be given to their weight status.

Time to grow up: readiness associated with improved clinical outcomes in pediatric inflammatory bowel disease patients undergoing transition

Background

The transition from pediatric to adult healthcare in individuals with inflammatory bowel disease (IBD) poses significant challenges mainly due to the high burden of IBD during adolescence, a critical period of psychosocial development. So far, there are few longitudinal data linking transition readiness to long-term disease outcomes.

Objective

We aimed to assess patients' readiness to transition and its impact on clinical outcomes, quality of life, and adherence to therapy.

Design

An observational, prospective study was conducted in a tertiary adult and pediatric center, including adolescents aged ⩾17 years with a diagnosis of IBD, who underwent a 'structured transition' program including two joint adult-pediatric visits.

Methods

Transition readiness skills were assessed with the Transition Readiness Assessment Questionnaire (TRAQ). All patients completed the TRAQ at the time of recruitment, which occurred during the initial joint adult-pediatric visit, to determine those deemed ready for transition versus those not ready. The Morisky Medication Adherence Scale and the 36-Item Short Form Health Survey Questionnaire (SF-36) were also completed at baseline and after 12 months. Clinical outcomes were collected at the 12-month follow-up.

Results

In all, 80 patients were enrolled who had transitioned through a structured transition clinic and completed 12 months of follow-up. In total, 54 patients were ready for the transition, with a mean TRAQ = 3.2 ± 0.5. The number of clinical relapses and hospitalizations at 12 months was lower in ready compared to not-ready patients (p = 0.004 and p = 0.04, respectively). SF-36 did not differ between ready and not-ready patients and pre- and post-transition clinics (p > 0.05). Based on the receiver operating characteristic curve, a TRAQ cutoff ⩾3.16 could predict medication adherence with a sensibility of 77%, a specificity of 82%, and an AUC of 0.81 (0.71-0.91; p < 0.001).

Conclusion

Patients ready for transition had better outcomes at 12 months compared to those who were not ready. Therefore, readiness assessment tools should be integrated into transition management to ensure that interventions are targeted, patient-centered, and responsive to individuals' changing needs.

Impact of Maternal Smoking, Offspring Smoking, and Genetic Susceptibility on Crohn's Disease and Ulcerative Colitis

BACKGROUND AND AIMS

The long-term impact of maternal smoking during pregnancy [MSDP] on the risk of Crohn's disease [CD] and ulcerative colitis [UC] in adult offspring remains uncertain. The present study aimed to investigate the individual and combined effects of early life exposure [MSDP], offspring personal behaviour [smoking], and genetic risk on the development of CD and UC in adult offspring.

METHODS

We conducted a prospective cohort study using UK Biobank data, including 334 083 participants recruited between 2006 and 2010, with follow-up until December 31, 2021. Multivariable Cox regression models were used to evaluate the associations of genetic factors, maternal and personal smoking, and their combination with CD and UC.

RESULTS

Participants exposed to MSDP had an 18% increased risk of CD compared to those without MSDP (hazard ratio [HR] = 1.18, 95% confidence interval [CI] = 1.01-1.39). However, no significant association was found between MSDP and UC risk [HR = 1.03, 95% CI = 0.92-1.16]. Personal smoking increased the risk of CD and UC, and had a numerically amplified effect with MSDP. Participants with high genetic risk and MSDP had a 2.01-fold [95% CI = 1.53-2.65] and a 2.45-fold [95% CI = 2.00-2.99] increased risk of CD and UC, respectively, compared to participants without MSDP and with low genetic risk.

CONCLUSIONS

Our prospective cohort study provides evidence that MSDP increases the risk of CD in adult offspring, whereas no evidence supports their causal association. Additionally, smoking and genetic susceptibility had a numerically amplified effect with MSDP on CD and UC, but the interaction lacked statistical significance.

Improved Clinical Outcomes With Early Anti-Tumour Necrosis Factor Alpha Therapy in Children With Newly Diagnosed Crohn's Disease: Real-world Data from the International Prospective PIBD-SETQuality Inception Cohort Study

BACKGROUND AND AIMS

Treatment guidelines for paediatric Crohn's disease [CD] suggest early use of anti-tumour necrosis factor alpha [anti-TNFα] in high-risk individuals. The aim is to evaluate the effect of early anti-TNF in a real-world cohort.

METHODS

Children with newly diagnosed CD were prospectively recruited at 28 participating sites of the international observational PIBD-SETQuality study. Outcomes were compared at 3 months, 1 and 2 years between patients receiving early anti-TNF [<90 days after diagnosis] and those not receiving early anti-TNF. Outcomes included sustained steroid-free remission [SSFR] without treatment intensification [specified as SSFR*] and sustained steroid-free mild/inactive disease without treatment intensification [specified as SSFMI*]. Penalised logistic regression model-based standardisation was applied to estimate the relative risks [RR] of early therapy on outcomes. RRs were estimated for high-risk and low-risk patients, based on presence of predictors of poor outcome [POPOs] and disease activity at diagnosis.

RESULTS

In total, 331 children (median age 13.9 years [IQR 12.2-15.3]) were enrolled, with 135 [41%] receiving early anti-TNF. At 1 year, patients on early anti-TNF had higher rates of SSFR* [30% vs 14%, p <0.001] and SSFMI* [69% vs 33%, p <0.001], with RRs of 2.95 [95% CI 1.63-5.36] and 4.67 [95% CI 2.46-8.87], respectively. At 1 year, the RRs for SSFMI* were higher, and statistically significant in high-risk patients, i.e. those with moderate/severe disease compared with mild/inactive disease at diagnosis (5.50 [95% CI 2.51-12.05] vs 2.91 [95% CI 0.92-9.11]), and those with any POPO compared with no POPO (5.05 [95% CI 2.45-10.43] vs 3.41 [95% CI 0.54-21.7]).

CONCLUSION

In this cohort of children with newly-diagnosed CD, early anti-TNF demonstrated superior effectiveness in high-risk patients.

Ultrastructural changes in chronic inflammatory enteropathies-a comparison between dogs and humans

Chronic inflammatory enteropathies (CIEs) are an important group of diseases in dogs and involve complex pathogenetic aspects. Endoscopy and histopathology are vital for documenting the disease but are less useful for subclassifying CIEs and predicting the response to treatment. However, healing of the mucosal disease process (deep remission) and ultrastructural evaluation of the mucosa have received little attention in canine CIE. Given that canine CIE shares many similarities with inflammatory bowel diseases (IBDs) in human patients-and presents a good spontaneous disease model for human IBD-this perspective article evaluates the literature on ultrastructural lesions in canine CIE and human IBD and offers future directions for the study of ultrastructural mucosal lesions in canine CIE. Such lesions might have a higher sensitivity of detection than structural changes revealed upon light microscopy and may even precede or remain after the resolution of the clinical signs and histologic lesions.

Casual associations of thyroid function with inflammatory bowel disease and the mediating role of cytokines

Background

Previous observational epidemiological studies have suggested a potential association between thyroid function and inflammatory bowel disease (IBD). However, the findings remain inconclusive, and whether this association is causal remains uncertain. The objective of this study is to investigate the causal association between thyroid function and IBD.

Methods

Genome-wide association studies (GWAS) involving seven indicators of thyroid function, IBD, and 41 cytokines were analyzed. Bidirectional two-sample Mendelian randomization (MR) and multivariable MR were conducted to examine the causal relationship between thyroid function and IBD and to explore the potential mechanisms underlying the associations.

Results

Genetically determined hypothyroidism significantly reduced the risk of CD (odds ratio [OR] = 0.761, 95% CI: 0.655-0.882, p < 0.001). Genetically determined reference-range TSH was found to have a suggestive causal effect on IBD (OR = 0.931, 95% CI: 0.888-0.976, p = 0.003), (Crohn disease) CD (OR = 0.915, 95% CI: 0.857-0.977, p = 0.008), and ulcerative colitis (UC) (OR =0.910, 95% CI: 0.830-0.997, p = 0.043). In reverse MR analysis, both IBD and CD appeared to have a suggestive causal effect on the fT3/fT4 ratio (OR = 1.002, p = 0.013 and OR = 1.001, p = 0.015, respectively). Among 41 cytokines, hypothyroidism had a significant impact on interferon-inducible protein-10 (IP-10) (OR = 1.465, 95% CI: 1.094-1.962, p = 0.010). The results of multivariable MR showed that IP-10 may mediate the causal effects of hypothyroidism with CD.

Conclusion

Our results suggest that an elevated TSH level reduces the risk of CD, with IP-10 potentially mediating this association. This highlights the pituitary-thyroid axis could serve as a potential therapeutic strategy for CD.

An isoform quantitative trait locus in SBNO2 links genetic susceptibility to Crohn's disease with defective antimicrobial activity

Despite major advances in linking single genetic variants to single causal genes, the significance of genetic variation on transcript-level regulation of expression, transcript-specific functions, and relevance to human disease has been poorly investigated. Strawberry notch homolog 2 (SBNO2) is a candidate gene in a susceptibility locus with different variants associated with Crohn's disease and bone mineral density. The SBNO2 locus is also differentially methylated in Crohn's disease but the functional mechanisms are unknown. Here we show that the isoforms of SBNO2 are differentially regulated by lipopolysaccharide and IL-10. We identify Crohn's disease associated isoform quantitative trait loci that negatively regulate the expression of the noncanonical isoform 2 corresponding with the methylation signals at the isoform 2 promoter in IBD and CD. The two isoforms of SBNO2 drive differential gene networks with isoform 2 dominantly impacting antimicrobial activity in macrophages. Our data highlight the role of isoform quantitative trait loci to understand disease susceptibility and resolve underlying mechanisms of disease.

A genome-wide meta-analysis of palmoplantar pustulosis implicates TH2 responses and cigarette smoking in disease pathogenesis

BACKGROUND

Palmoplantar pustulosis (PPP) is an inflammatory skin disorder that mostly affects smokers and manifests with painful pustular eruptions on the palms and soles. Although the disease can present with concurrent plaque psoriasis, TNF and IL-17/IL-23 inhibitors show limited efficacy. There is therefore a pressing need to uncover PPP disease drivers and therapeutic targets.

OBJECTIVES

We sought to identify genetic determinants of PPP and investigate whether cigarette smoking contributes to disease pathogenesis.

METHODS

We performed a genome-wide association meta-analysis of 3 North-European cohorts (n = 1,456 PPP cases and 402,050 controls). We then used the scGWAS program to investigate the cell-type specificity of the association signals. We also undertook genetic correlation analyses to examine the similarities between PPP and other immune-mediated diseases. Finally, we applied Mendelian randomization to analyze the causal relationship between cigarette smoking and PPP.

RESULTS

We found that PPP is not associated with the main genetic determinants of plaque psoriasis. Conversely, we identified genome-wide significant associations with the FCGR3A/FCGR3B and CCHCR1 loci. We also observed 13 suggestive (P < 5 × 10-6) susceptibility regions, including the IL4/IL13 interval. Accordingly, we demonstrated a significant genetic correlation between PPP and TH2-mediated diseases such as atopic dermatitis and ulcerative colitis. We also found that genes mapping to PPP-associated intervals were preferentially expressed in dendritic cells and often implicated in T-cell activation pathways. Finally, we undertook a Mendelian randomization analysis, which supported a causal role of cigarette smoking in PPP.

CONCLUSIONS

The first genome-wide association study of PPP points to a pathogenic role for deregulated TH2 responses and cigarette smoking.

IL-22 promotes mucin-type O-glycosylation and MATH1+ cell-mediated amelioration of intestinal inflammation

The interleukin (IL)-22 cytokine can be protective or inflammatory in the intestine. It is unclear if IL-22 receptor (IL-22Ra1)-mediated protection involves a specific type of intestinal epithelial cell (IEC). By using a range of IEC type-specific Il22Ra1 conditional knockout mice and a dextran sulfate sodium (DSS) colitis model, we demonstrate that IL-22Ra1 signaling in MATH1+ cells (goblet and progenitor cells) is essential for maintaining the mucosal barrier and intestinal tissue regeneration. The IL-22Ra1 signaling in IECs promotes mucin core-2 O-glycan extension and induces beta-1,3-galactosyltransferase 5 (B3GALT5) expression in the colon. Adenovirus-mediated expression of B3galt5 is sufficient to rescue Il22Ra1IEC mice from DSS colitis. Additionally, we observe a reduction in the expression of B3GALT5 and the Tn antigen, which indicates defective mucin O-glycan, in the colon tissue of patients with ulcerative colitis. Lastly, IL-22Ra1 signaling in MATH1+ progenitor cells promotes organoid regeneration after DSS injury. Our findings suggest that IL-22-dependent protective responses involve O-glycan modification, proliferation, and differentiation in MATH1+ progenitor cells.

A Polygenic Risk Analysis for Identifying Ulcerative Colitis Patients with European Ancestry

The incidence of ulcerative colitis (UC) has increased globally. As a complex disease, the genetic predisposition for UC could be estimated by the polygenic risk score (PRS), which aggregates the effects of a large number of genetic variants in a single quantity and shows promise in identifying individuals at higher lifetime risk of UC. Here, based on a cohort of 2869 UC cases and 2900 controls with genotype array datasets, we used PRSice-2 to calculate PRS, and systematically analyzed factors that could affect the power of PRS, including GWAS summary statistics, population stratification, and impact of variants. After leveraging a stepwise condition analysis, we eventually established the best PRS model, achieving an AUC of 0.713. Meanwhile, samples in the top 20% of the PRS distribution had a risk of UC more than ten times higher than samples in the lowest 20% (OR = 10.435, 95% CI 8.571-12.703). Our analyses demonstrated that including population-enriched, more disease-associated SNPs and using GWAS summary statistics from similar ethnic background can improve the power of PRS. Strictly following the principle of focusing on one population in all aspects of generating PRS can be a cost-effective way to apply genotype-array-derived PRS to practical risk estimation.

Bidirectional communication of the gut-brain axis: new findings in Parkinson's disease and inflammatory bowel disease

Parkinson's disease (PD) and inflammatory bowel disease (IBD) are the two chronic inflammatory diseases that are increasingly affecting millions of people worldwide, posing a major challenge to public health. PD and IBD show similarities in epidemiology, genetics, immune response, and gut microbiota. Here, we review the pathophysiology of these two diseases, including genetic factors, immune system imbalance, changes in gut microbial composition, and the effects of microbial metabolites (especially short-chain fatty acids). We elaborate on the gut-brain axis, focusing on role of gut microbiota in the pathogenesis of PD and IBD. In addition, we discuss several therapeutic strategies, including drug therapy, fecal microbiota transplantation, and probiotic supplementation, and their potential benefits in regulating intestinal microecology and relieving disease symptoms. Our analysis will provide a new understanding and scientific basis for the development of more effective therapeutic strategies for these diseases.

Isorhamnetin alleviates ferroptosis-mediated colitis by activating the NRF2/HO-1 pathway and chelating iron

Ferroptosis of intestinal epithelial cells (IECs) had been identified as a key factor in the development of ulcerative colitis (UC). Therefore, targeted inhibition of ferroptosis may provide a new strategy for the treatment of UC. Isorhamnetin (ISO) was an O-methylated flavonol with therapeutic effects on a variety of diseases, such as cardiovascular disease, neurological disorders and tumors. However, the role and mechanism of ISO in ferroptosis and associated colitis were rarely investigated. In this study, we demonstrated that ISO could effectively alleviate intestinal inflammation by inhibiting ferroptosis of IECs in DSS-induced mice. Moreover, our results shown that ISO acted as a potent and common ferroptosis inhibitor in multiple human and murine cell lines. Mechanistically, ISO inhibited ferroptosis independent of its previously reported targets MEK1 and PI3K, but alleviated oxidative stress by targeting and activating NRF2. Furthermore, ISO could also directly chelate iron to hinder ferroptosis. In conclusion, our study indicated that ISO as a novel potential ferroptosis inhibitor, providing a promising therapeutic strategy for ferroptosis-related colitis.

Landscape of TPMT and NUDT15 Pharmacogenetic Variation in a Cohort of Canadian Pediatric Inflammatory Bowel Disease Patients

BACKGROUND

Patients with inflammatory bowel disease (IBD) exhibit considerable interindividual variability in medication response, highlighting the need for precision medicine approaches to optimize and tailor treatment. Pharmacogenetics (PGx) offers the ability to individualize dosing by examining genetic factors underlying the metabolism of medications such as thiopurines. Pharmacogenetic testing can identify individuals who may be at risk for thiopurine dose-dependent adverse reactions including myelosuppression. We aimed to evaluate PGx variation in genes supported by clinical guidelines that inform dosing of thiopurines and characterize differences in the distribution of actionable PGx variation among diverse ancestral groups.

METHODS

Pharmacogenetic variation in TPMT and NUDT15 was captured by genome-wide genotyping of 1083 pediatric IBD patients from a diverse Canadian cohort. Genetic ancestry was inferred using principal component analysis. The proportion of PGx variation and associated metabolizer status phenotypes was compared across 5 genetic ancestral groups within the cohort (Admixed American, African, East Asian, European, and South Asian) and to prior global estimates from corresponding populations.

RESULTS

Collectively, 11% of the cohort was categorized as intermediate or poor metabolizers of thiopurines, which would warrant a significant dose reduction or selection of alternate therapy. Clinically actionable variation in TPMT was more prevalent in participants of European and Admixed American/Latino ancestry (8.7% and 7.5%, respectively), whereas variation in NUDT15 was more prevalent in participants of East Asian and Admixed American/Latino ancestry (16% and 15% respectively).

CONCLUSIONS

These findings demonstrate the considerable interpopulation variability in PGx variation underlying thiopurine metabolism, which should be factored into testing diverse patient populations.

Proteome-wide Mendelian randomization identifies potential therapeutic targets for nonalcoholic fatty liver diseases

Nonalcoholic fatty liver disease (NAFLD) is the predominant cause of liver pathology. Current evidence highlights plasma proteins as potential therapeutic targets. However, their mechanistic roles in NAFLD remain unclear. This study investigated the involvement of specific plasma proteins and intermediate risk factors in NAFLD progression. Two-sample Mendelian randomization (MR) analysis was conducted to examine the association between plasma proteins and NAFLD. Colocalization analysis determined the shared causal variants between the identified proteins and NAFLD. The MR analysis was applied separately to proteins, risk factors, and NAFLD. Mediator shares were computed by detecting the correlations among these elements. Phenome-wide association studies (phewas) were utilized to assess the safety implications of targeting these proteins. Among 1,834 cis-protein quantitative trait loci (cis-pQTLs), after-FDR correction revealed correlations between the plasma levels of four gene-predicted proteins (CSPG3, CILP2, Apo-E, and GCKR) and NAFLD. Colocalization analysis indicated shared causal variants for CSPG3 and GCKR in NAFLD (posterior probability > 0.8). Out of the 22 risk factors screened for MR analysis, only 8 showed associations with NAFLD (p ≤ 0.05), while 4 linked to CSPG3 and GCKR. The mediator shares for these associations were calculated separately. Additionally, reverse MR analysis was performed on the pQTLs, risk factors, and NAFLD, which exhibited a causal relationship with forward MR analysis. Finally, phewas summarized the potential side effects of associated-targeting proteins, including CSPG3 and GCKR. Our research emphasized the potential therapeutic targets for NAFLD and provided modifiable risk factors for preventing NAFLD.

Challenges in IBD Research 2024: Environmental Triggers

Environmental factors play an important role in inflammatory bowel diseases (IBD; Crohn's disease, [CD], ulcerative colitis [UC]). As part of the Crohn's & Colitis Challenges 2024 agenda, the Environmental Triggers workgroup summarized the progress made in the field of environmental impact on IBD since the last Challenges cycle in this document. The workgroup identified 4 unmet gaps in this content area pertaining to 4 broad categories: (1) Epidemiology; (2) Exposomics and environmental measurement; (3) Biologic mechanisms; and (4) Interventions and Implementation. Within epidemiology, the biggest unmet gaps were in the study of environmental factors in understudied populations including racial and ethnic minority groups and in populations witnessing rapid rise in disease incidence globally. The workgroup also identified a lack of robust knowledge of how environmental factors may impact difference stages of the disease and for different disease-related end points. Leveraging existing cohorts and targeted new prospective studies were felt to be an important need for the field. The workgroup identified the limitations of traditional questionnaire-based assessment of environmental exposure and placed high priority on the identification of measurable biomarkers that can quantify cross-sectional and longitudinal environmental exposure. This would, in turn, allow for identifying the biologic mechanisms of influence of environmental factors on IBD and understand the heterogeneity in effect of such influences. Finally, the working group emphasized the importance of generating high-quality data on effective environmental modification on an individual and societal level, and the importance of scalable and sustainable methods to deliver such changes.

Challenges in IBD Research 2024: Preclinical Human IBD Mechanisms

Preclinical human inflammatory bowel disease (IBD) mechanisms is one of 5 focus areas of the Challenges in IBD Research 2024 document, which also includes environmental triggers, novel technologies, precision medicine, and pragmatic clinical research. Herein, we provide a comprehensive overview of current gaps in inflammatory bowel diseases research that relate to preclinical research and deliver actionable approaches to address them with a focus on how these gaps can lead to advancements in IBD interception, remission, and restoration. The document is the result of multidisciplinary input from scientists, clinicians, patients, and funders and represents a valuable resource for patient-centric research prioritization. This preclinical human IBD mechanisms section identifies major research gaps whose investigation will elucidate pathways and mechanisms that can be targeted to address unmet medical needs in IBD. Research gaps were identified in the following areas: genetics, risk alleles, and epigenetics; the microbiome; cell states and interactions; barrier function; IBD complications (specifically fibrosis and stricturing); and extraintestinal manifestations. To address these gaps, we share specific opportunities for investigation for basic and translational scientists and identify priority actions.

SLAMF8 can predict prognosis of pan-cancer and the immunotherapy response effectivity of gastric cancer

SLAMF8, the eighth member of the Signaling Lymphocytic Activation Molecule Family (SLAMF), functions in the regulation of the development and activity of diverse immune cells as a costimulatory receptor within the SLAMF family. Studies had revealed that SLAMF8 is expressed higher in several autoimmune inflammation diseases and tumors. Nevertheless, the connection between SLAMF8 and pan-cancer remains undisclosed. The research investigated the correlation between SLAMF8 and various factors including the immune microenvironment, microsatellite instability, immune novel antigen, gene mutation, immune regulatory factors, immune blockade TMB, and immune or molecular subtypes of SLAMF8 in verse cancer types. Immunohistochemistry was ultimately employed to validate the presence of the SLAMF8 gene in various tumor types including hepatocellular carcinoma, prostate adenocarcinoma, and kidney renal clear cell carcinoma. Furthermore, the relationship between SLAMF8 expression and the therapeutic efficacy of the PD1 blockade agent, Sintilimab, treatment in gastric cancer was validated. The result of differential analysis suggested that SLAMF8 was over-expressed in pan-cancer compared with paracancerous tissues. The analysis of survival indicated a connection between SLAMF8 and the overall prognosis in different types of cancers, where higher levels of SLAMF8 were found to be significantly linked to unfavorable outcomes in patients but favorable outcome of immunotherapy in gastric cancer. Significant correlations were observed between SLAMF8 levels and pan-cancer tumorigenesis, tumor metabolism, and immunity. As a result, SLAMF8 may become an important prognostic biomarker in the majority of tumors and a hopeful gene target for immunotherapy against gastric cancer.

Inferring causal cell types of human diseases and risk variants from candidate regulatory elements

The heritability of human diseases is extremely enriched in candidate regulatory elements (cRE) from disease-relevant cell types. Critical next steps are to infer which and how many cell types are truly causal for a disease (after accounting for co-regulation across cell types), and to understand how individual variants impact disease risk through single or multiple causal cell types. Here, we propose CT-FM and CT-FM-SNP, two methods that leverage cell-type-specific cREs to fine-map causal cell types for a trait and for its candidate causal variants, respectively. We applied CT-FM to 63 GWAS summary statistics (average N = 417K) using nearly one thousand cRE annotations, primarily coming from ENCODE4. CT-FM inferred 81 causal cell types with corresponding SNP-annotations explaining a high fraction of trait SNP-heritability (~2/3 of the SNP-heritability explained by existing cREs), identified 16 traits with multiple causal cell types, highlighted cell-disease relationships consistent with known biology, and uncovered previously unexplored cellular mechanisms in psychiatric and immune-related diseases. Finally, we applied CT-FM-SNP to 39 UK Biobank traits and predicted high confidence causal cell types for 2,798 candidate causal non-coding SNPs. Our results suggest that most SNPs impact a phenotype through a single cell type, and that pleiotropic SNPs target different cell types depending on the phenotype context. Altogether, CT-FM and CT-FM-SNP shed light on how genetic variants act collectively and individually at the cellular level to impact disease risk.

Changing epidemiology of inflammatory bowel disease in children and adolescents

BACKGROUND

The incidence of inflammatory bowel disease (IBD) is rising worldwide, but epidemiological data on children and adolescents are lacking. Understanding the global burden of IBD among children and adolescents is essential for global standardization of methodology and treatment options.

METHODS

This is a cross-sectional study based on aggregated data. We estimated the prevalence and incidence of IBD in children and adolescents between 1990 and 2019 according to the Global Burden of Disease Study 2019 (GBD 2019). Age-standardized rates (ASRs) and estimated annual percentage changes (EAPCs) were used to compare the burden and trends between different regions and countries.

RESULTS

In 2019, there were 25,659 new cases and 88,829 prevalent cases of IBD among children and adolescents globally, representing an increase of 22.8% and 18.5%, respectively, compared to 1990. Over the past 30 years, the incidence and prevalence of IBD among children and adolescents have been highest in high SDI regions, with the most significant increases in East Asia and high-income Asia Pacific. At the age level, incidence and prevalence were significantly higher in the 15-19-year-old age group, while the < 5-year-old group showed the most significant increase in incidence and prevalence.

CONCLUSION

The incidence of IBD in children and adolescents is significantly on the rise in some countries and regions, and IBD will remain an important public health issue with extensive healthcare and economic costs in the future. The reported IBD burden in children and adolescents at the global, regional, and national levels will assist in the development of more precise health policies.

Breaking down causes, consequences, and mediating effects of telomere length variation on human health

BACKGROUND

Telomeres form repeated DNA sequences at the ends of chromosomes, which shorten with each cell division. Yet, factors modulating telomere attrition and the health consequences thereof are not fully understood. To address this, we leveraged data from 326,363 unrelated UK Biobank participants of European ancestry.

RESULTS

Using linear regression and bidirectional univariable and multivariable Mendelian randomization (MR), we elucidate the relationships between leukocyte telomere length (LTL) and 142 complex traits, including diseases, biomarkers, and lifestyle factors. We confirm that telomeres shorten with age and show a stronger decline in males than in females, with these factors contributing to the majority of the 5.4% of LTL variance explained by the phenome. MR reveals 23 traits modulating LTL. Smoking cessation and high educational attainment associate with longer LTL, while weekly alcohol intake, body mass index, urate levels, and female reproductive events, such as childbirth, associate with shorter LTL. We also identify 24 traits affected by LTL, with risk for cardiovascular, pulmonary, and some autoimmune diseases being increased by short LTL, while longer LTL increased risk for other autoimmune conditions and cancers. Through multivariable MR, we show that LTL may partially mediate the impact of educational attainment, body mass index, and female age at childbirth on proxied lifespan.

CONCLUSIONS

Our study sheds light on the modulators, consequences, and the mediatory role of telomeres, portraying an intricate relationship between LTL, diseases, lifestyle, and socio-economic factors.

Causal relationship between primary biliary cholangitis and inflammatory bowel disease: a Mendelian randomization study

Background

Several studies indicated that inflammatory bowel disease (IBD) may contribute to increased susceptibility to primary biliary cholangitis (PBC). However, the causal relationship between IBD and PBC remains unclear.

Methods

The genetic variant data of patients with IBD and PBC were obtained from published genome-wide association studies (GWASs). The IBD data were further divided into a discovery dataset and a validation dataset depending on the data source. We conducted a two-sample Mendelian randomization (MR) analysis using the inverse variance weighting (IVW), MR-Egger, weighted median (WM), MR robust adjusted profile score (MR-RAPS), and maximum likelihood (ML) methods, with IVW being the main focus, to verify the causal relationship between IBD and PBC. Additionally, a series of sensitivity analyses were performed to ensure the reliability of the results.

Results

In the discovery cohort, the IVW analysis results (OR = 1.114, P = 0.011) indicated a significant association between IBD and PBC. The MR-RAPS (OR = 1.130, P = 0.007) and ML (OR = 1.115, P = 0.011) analyses yielded results consistent with those of IVW in confirming IBD as a risk factor for PBC. In the validation cohort, consistent findings were observed regarding the causal relationship between IBD and PBC using IVW, MR-RAPS, and ML analyses; all three methods identified IBD as a risk factor for developing PBC. By the IVW analysis, Crohn's disease (CD) emerged as the most prominent subtype of IBD associated with an increased risk of developing PBC in both the discovery cohort (OR = 1.068, P = 0.049) and the validation cohort (OR = 1.082, P = 0.019).

Conclusion

The results of the MR analysis suggest a causal relationship between IBD and PBC, highlighting the necessity for proactive PBC prevention in patients with IBD, particularly those with CD.

Evaluation of Deficient Nutrients in Infants and Toddlers Mainly Taking Amino Acid-Based Elemental Formulas: An Exploratory Study

INTRODUCTION

This study evaluated nutrient deficiencies in infants and toddlers with inflammatory bowel disease (IBD) and eosinophilic gastrointestinal disorders (EGIDs), whose primary nutritional source is elemental formulas (EFs).

METHODS

The nutrient status of children with IBD and EGID aged 6 months to 6 years was evaluated.

RESULTS

Twenty-one children fed with EFs (EF group) and 25 controls (CL group) were enrolled. The selenium level in the EF group was lower than that in the CL group (2.2 μg/dL vs. 9.3 μg/dL; p < 0.01). Although fat-soluble vitamins were deficient in some EF group participants, no significant differences were observed in their concentration and insufficiency proportion. However, ascorbic acid deficiency was more frequent in the EF group, with significantly lower levels (8.6 μg/mL vs. 12.0 μg/mL; p < 0.01). The triene:tetraene ratio was significantly higher in the EF group (0.046 vs. 0.010; p < 0.01). Asparagine and taurine levels were significantly lower in the EF group (asparagine: p < 0.01; taurine: p < 0.01) and tyrosine and phenylalanine levels were higher in the EF group, resulting in a lower Fisher's ratio (p < 0.01).

CONCLUSION

Long-term feeding with EFs can cause deficiencies in essential fatty acids, selenium, and ascorbic acid and also carries a risk of amino acid imbalance in infants and toddlers.

Fecal proteolytic profiling of pediatric inflammatory bowel disease: A pilot study

Colonoscopy is the gold standard for diagnosing inflammatory bowel disease (IBD). However, this invasive procedure has a high burden for pediatric patients. Previous research has shown elevated fecal amino acid concentrations in children with IBD versus controls. We hypothesized that this finding could result from increased proteolytic activity. Therefore, the aim of this study was to investigate whether fecal protease-based profiling was able to discriminate between IBD and controls. Protease activity was measured in fecal samples from patients with IBD (Crohn's disease (CD) n = 19; ulcerative colitis (UC) n = 19) and non-IBD controls (n = 19) using a fluorescence resonance energy transfer (FRET)-peptide library. Receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of each FRET-peptide substrate. Screening the FRET-peptide library revealed an increased total proteolytic activity (TPA), as well as degradation of specific FRET-peptides specifically in fecal samples from IBD patients. Based on level of significance (p < .001) and ROC curve analysis (AUC > 0.85), the fluorogenic substrates W-W, A-A, a-a, F-h, and H-y showed diagnostic potential for CD. The substrates W-W, a-a, T-t, G-v, and H-y showed diagnostic potential for UC based on significance (p < .001) and ROC analysis (AUC > 0.90). None of the FRET-peptide substrates used was able to differentiate between protease activity in fecal samples from CD versus UC. This study showed an increased fecal proteolytic activity in children with newly diagnosed, treatment-naïve, IBD. This could lead to the development of novel, noninvasive biomarkers for screening and diagnostic purposes.

Genotype-based "virtual" metabolomics in a clinical biobank identifies novel metabolite-disease associations

Introduction: Circulating metabolites act as biomarkers of dysregulated metabolism and may inform disease pathophysiology. A portion of the inter-individual variability in circulating metabolites is influenced by common genetic variation. We evaluated whether a genetics-based "virtual" metabolomics approach can identify novel metabolite-disease associations. Methods: We examined the association between polygenic scores for 724 metabolites with 1,247 clinical phenotypes in the BioVU DNA biobank, comprising 57,735 European ancestry and 15,754 African ancestry participants. We applied Mendelian randomization (MR) to probe significant relationships and validated significant MR associations using independent GWAS of candidate phenotypes. Results and Discussion: We found significant associations between 336 metabolites and 168 phenotypes in European ancestry and 107 metabolites and 56 phenotypes in African ancestry. Of these metabolite-disease pairs, MR analyses confirmed associations between 73 metabolites and 53 phenotypes in European ancestry. Of 22 metabolitephenotype pairs evaluated for replication in independent GWAS, 16 were significant (false discovery rate p < 0.05). These included associations between bilirubin and X-21796 with cholelithiasis, phosphatidylcholine (16:0/22:5n3,18:1/20:4) and arachidonate with inflammatory bowel disease and Crohn's disease, and campesterol with coronary artery disease and myocardial infarction. These associations may represent biomarkers or potentially targetable mediators of disease risk.

The landscape of rare genetic variation associated with inflammatory bowel disease and Parkinson's disease comorbidity

BACKGROUND

Inflammatory bowel disease (IBD) and Parkinson's disease (PD) are chronic disorders that have been suggested to share common pathophysiological processes. LRRK2 has been implicated as playing a role in both diseases. Exploring the genetic basis of the IBD-PD comorbidity through studying high-impact rare genetic variants can facilitate the identification of the novel shared genetic factors underlying this comorbidity.

METHODS

We analyzed whole exomes from the BioMe BioBank and UK Biobank, and whole genomes from a cohort of 67 European patients diagnosed with both IBD and PD to examine the effects of LRRK2 missense variants on IBD, PD and their co-occurrence (IBD-PD). We performed optimized sequence kernel association test (SKAT-O) and network-based heterogeneity clustering (NHC) analyses using high-impact rare variants in the IBD-PD cohort to identify novel candidate genes, which we further prioritized by biological relatedness approaches. We conducted phenome-wide association studies (PheWAS) employing BioMe BioBank and UK Biobank whole exomes to estimate the genetic relevance of the 14 prioritized genes to IBD-PD.

RESULTS

The analysis of LRRK2 missense variants revealed significant associations of the G2019S and N2081D variants with IBD-PD in addition to several other variants as potential contributors to increased or decreased IBD-PD risk. SKAT-O identified two significant genes, LRRK2 and IL10RA, and NHC identified 6 significant gene clusters that are biologically relevant to IBD-PD. We observed prominent overlaps between the enriched pathways in the known IBD, PD, and candidate IBD-PD gene sets. Additionally, we detected significantly enriched pathways unique to the IBD-PD, including MAPK signaling, LPS/IL-1 mediated inhibition of RXR function, and NAD signaling. Fourteen final candidate IBD-PD genes were prioritized by biological relatedness methods. The biological importance scores estimated by protein-protein interaction networks and pathway and ontology enrichment analyses indicated the involvement of genes related to immunity, inflammation, and autophagy in IBD-PD. Additionally, PheWAS provided support for the associations of candidate genes with IBD and PD.

CONCLUSIONS

Our study confirms and uncovers new LRRK2 associations in IBD-PD. The identification of novel inflammation and autophagy-related genes supports and expands previous findings related to IBD-PD pathogenesis, and underscores the significance of therapeutic interventions for reducing systemic inflammation.

The development of probiotics and prebiotics therapy to ulcerative colitis: a therapy that has gained considerable momentum

Ulcerative colitis (UC) is increasingly common, and it is gradually become a kind of global epidemic. UC is a type of inflammatory bowel disease (IBD), and it is a lifetime recurrent disease. UC as a common disease has become a financial burden for many people and has the potential to develop into cancer if not prevented or treated. There are multiple factors such as genetic factors, host immune system disorders, and environmental factors to cause UC. A growing body of research have suggested that intestinal microbiota as an environmental factor play an important role in the occurrence and development of UC. Meanwhile, evidence to date suggests that manipulating the gut microbiome may represent effective treatment for the prevention or management of UC. In addition, the main clinical drugs to treat UC are amino salicylate and corticosteroid. These clinical drugs always have some side effects and low success rate when treating patients with UC. Therefore, there is an urgent need for safe and efficient methods to treat UC. Based on this, probiotics and prebiotics may be a valuable treatment for UC. In order to promote the wide clinical application of probiotics and prebiotics in the treatment of UC. This review aims to summarize the recent literature as an aid to better understanding how the probiotics and prebiotics contributes to UC while evaluating and prospecting the therapeutic effect of the probiotics and prebiotics in the treatment of UC based on previous publications.

Advances and optimization strategies in bacteriophage therapy for treating inflammatory bowel disease

In the advancement of Inflammatory Bowel Disease (IBD) treatment, existing therapeutic methods exhibit limitations; they do not offer a complete cure for IBD and can trigger adverse side effects. Consequently, the exploration of novel therapies and multifaceted treatment strategies provides patients with a broader range of options. Within the framework of IBD, gut microbiota plays a pivotal role in disease onset through diverse mechanisms. Bacteriophages, as natural microbial regulators, demonstrate remarkable specificity by accurately identifying and eliminating specific pathogens, thus holding therapeutic promise. Although clinical trials have affirmed the safety of phage therapy, its efficacy is prone to external influences during storage and transport, which may affect its infectivity and regulatory roles within the microbiota. Improving the stability and precise dosage control of bacteriophages-ensuring robustness in storage and transport, consistent dosing, and targeted delivery to infection sites-is crucial. This review thoroughly explores the latest developments in IBD treatment and its inherent challenges, focusing on the interaction between the microbiota and bacteriophages. It highlights bacteriophages' potential as microbiome modulators in IBD treatment, offering detailed insights into research on bacteriophage encapsulation and targeted delivery mechanisms. Particular attention is paid to the functionality of various carrier systems, especially regarding their protective properties and ability for colon-specific delivery. This review aims to provide a theoretical foundation for using bacteriophages as microbiome modulators in IBD treatment, paving the way for enhanced regulation of the intestinal microbiota.

Multi-Omics Characterization of Colon Mucosa and Submucosa/Wall from Crohn's Disease Patients

Crohn's disease (CD) is a subtype of inflammatory bowel disease (IBD) characterized by transmural disease. The concept of transmural healing (TH) has been proposed as an indicator of deep clinical remission of CD and as a predictor of favorable treatment endpoints. Understanding the pathophysiology involved in transmural disease is critical to achieving these endpoints. However, most studies have focused on the intestinal mucosa, overlooking the contribution of the intestinal wall in Crohn's disease. Multi-omics approaches have provided new avenues for exploring the pathogenesis of Crohn's disease and identifying potential biomarkers. We aimed to use transcriptomic and proteomic technologies to compare immune and mesenchymal cell profiles and pathways in the mucosal and submucosa/wall compartments to better understand chronic refractory disease elements to achieve transmural healing. The results revealed similarities and differences in gene and protein expression profiles, metabolic mechanisms, and immune and non-immune pathways between these two compartments. Additionally, the identification of protein isoforms highlights the complex molecular mechanisms underlying this disease, such as decreased RTN4 isoforms (RTN4B2 and RTN4C) in the submucosa/wall, which may be related to the dysregulation of enteric neural processes. These findings have the potential to inform the development of novel therapeutic strategies to achieve TH.

Research progress of ferroptosis and inflammatory bowel disease

Inflammatory bowel disease (IBD) is a non-specific chronic inflammatory disorder of the gastrointestinal tract, imposing significant burdens on both society and individuals. As a new type of regulated cell death (RCD), ferroptosis is different from classic RCDs such as apoptosis and necrosis in cell morphology, biochemistry and genetics. The main molecular mechanisms of ferroptosis include dysregulation of iron metabolism, impaired antioxidant capacity, mitochondrial dysfunction, accumulation of lipid-associated super-oxides, and membrane disruption. In recent years, increasing evidence has shown that ferroptosis is involved in the pathophysiology of inflammatory bowel disease. However, the exact roles and underlying molecular mechanisms have not been fully elucidated. This article reviews the mechanism of ferroptosis in the occurrence and development of inflammatory bowel disease, in order to provide new ideas for the pathophysiological research of inflammatory bowel disease. Additionally, we discuss potential strategies for the prevention and treatment of inflammatory bowel disease by targeting ferroptosis.

Bacterial Sphingolipids Exacerbate Colitis by Inhibiting ILC3-derived IL-22 Production

BACKGROUND & AIMS

Gut bacterial sphingolipids, primarily produced by Bacteroidetes, have dual roles as bacterial virulence factors and regulators of the host mucosal immune system, including regulatory T cells and invariant natural killer T cells. Patients with inflammatory bowel disease display altered sphingolipids profiles in fecal samples. However, how bacterial sphingolipids modulate mucosal homeostasis and regulate intestinal inflammation remains unclear.

METHODS

We used dextran sodium sulfate (DSS)-induced colitis in mice monocolonized with Bacteroides fragilis strains expressing or lacking sphingolipids to assess the influence of bacterial sphingolipids on intestinal inflammation using transcriptional, protein, and cellular analyses. Colonic explant and organoid were used to study the function of bacterial sphingolipids. Host mucosal immune cells and cytokines were profiled and characterized using flow cytometry, enzyme-linked immunosorbent assay, and Western blot, and cytokine function in vivo was investigated by monoclonal antibody injection.

RESULTS

B fragilis sphingolipids exacerbated intestinal inflammation. Mice monocolonized with B fragilis lacking sphingolipids exhibited less severe DSS-induced colitis. This amelioration of colitis was associated with increased production of interleukin (IL)-22 by ILC3. Mice colonized with B fragilis lacking sphingolipids following DSS treatment showed enhanced epithelial STAT3 activity, intestinal cell proliferation, and antimicrobial peptide production. Protection against DSS colitis associated with B fragilis lacking sphingolipids was reversed on IL22 blockade. Furthermore, bacterial sphingolipids restricted epithelial IL18 production following DSS treatment and interfered with IL22 production by a subset of ILC3 cells expressing both IL18R and major histocompatibility complex class II.

CONCLUSIONS

B fragilis-derived sphingolipids exacerbate mucosal inflammation by impeding epithelial IL18 expression and concomitantly suppressing the production of IL22 by ILC3 cells.

A powerful approach to identify replicable variants in genome-wide association studies

Replicability is the cornerstone of modern scientific research. Reliable identifications of genotype-phenotype associations that are significant in multiple genome-wide association studies (GWASs) provide stronger evidence for the findings. Current replicability analysis relies on the independence assumption among single-nucleotide polymorphisms (SNPs) and ignores the linkage disequilibrium (LD) structure. We show that such a strategy may produce either overly liberal or overly conservative results in practice. We develop an efficient method, ReAD, to detect replicable SNPs associated with the phenotype from two GWASs accounting for the LD structure. The local dependence structure of SNPs across two heterogeneous studies is captured by a four-state hidden Markov model (HMM) built on two sequences of p values. By incorporating information from adjacent locations via the HMM, our approach provides more accurate SNP significance rankings. ReAD is scalable, platform independent, and more powerful than existing replicability analysis methods with effective false discovery rate control. Through analysis of datasets from two asthma GWASs and two ulcerative colitis GWASs, we show that ReAD can identify replicable genetic loci that existing methods might otherwise miss.

Forecasting the future prevalence of inflammatory bowel disease in Korea through 2048: an epidemiologic study employing autoregressive integrated moving average models

BACKGROUND AND AIM

The global inflammatory bowel disease (IBD) escalation has precipitated an increased disease burden and economic impact, particularly in Asia. This study primarily aimed to predict the future prevalence of IBD in Korea and elucidate its evolution pattern.

METHODS

Using a validated diagnostic algorithm, we analyzed data from the Korean National Health Insurance Service between 2004 and 2017 to identify patients with IBD. We predicted the number and prevalence of patients with IBD from 2018 to 2048 with the autoregressive integrated moving average method. A generalized linear model (GLM) was also employed to identify factors contributing to the observed trend in IBD prevalence.

RESULTS

Our prediction model validation demonstrated an acceptable error range for IBD prevalence, with a 2.45% error rate and a mean absolute difference of 2.61. We foresee a sustained average annual increase of 4.51 IBD cases per 100 000, culminating in a prevalence of 239.73 per 100 000 by 2048. The forecasted average annual percent change was 6.17% for males and 2.75% for females over the next 30 years. The GLM analysis revealed that age, gender and time significantly impact the prevalence of IBD, with notable disparities observed between genders in specific age groups for both Crohn's disease and ulcerative colitis (all interaction P < 0.05).

CONCLUSIONS

Our study forecasts a notable increase in Korean IBD prevalence by 2048, particularly among males and the 20-39 age group, highlighting the need to focus on these high-risk groups to mitigate the future disease burden.

Shaping immunity: The influence of natural selection on population immune diversity

Humans exhibit considerable variability in their immune responses to the same immune challenges. Such variation is widespread and affects individual and population-level susceptibility to infectious diseases and immune disorders. Although the factors influencing immune response diversity are partially understood, what mechanisms lead to the wide range of immune traits in healthy individuals remain largely unexplained. Here, we discuss the role that natural selection has played in driving phenotypic differences in immune responses across populations and present-day susceptibility to immune-related disorders. Further, we touch on future directions in the field of immunogenomics, highlighting the value of expanding this work to human populations globally, the utility of modeling the immune response as a dynamic process, and the importance of considering the potential polygenic nature of natural selection. Identifying loci acted upon by evolution may further pinpoint variants critically involved in disease etiology, and designing studies to capture these effects will enrich our understanding of the genetic contributions to immunity and immune dysregulation.

Viruses and autophagy: bend, but don't break

Autophagy is a constitutive cellular process of degradation required to maintain homeostasis and turn over spent organelles and aggregated proteins. For some viruses, the process can be antiviral, degrading viral proteins or virions themselves. For many other viruses, the induction of the autophagic process provides a benefit and promotes viral replication. In this Review, we survey the roles that the autophagic pathway plays in the replication of viruses. Most viruses that benefit from autophagic induction block autophagic degradation, which is a 'bend, but don't break' strategy initiating but limiting a potentially antiviral response. In almost all cases, it is other effects of the redirected autophagic machinery that benefit these viruses. This rapid mechanism to generate small double-membraned vesicles can be usurped to shape membranes for viral genome replication and virion maturation. However, data suggest that autophagic maintenance of cellular homeostasis is crucial for the initiation of infection, as viruses have evolved to replicate in normal, healthy cells. Inhibition of autophagic degradation is important once infection has initiated. Although true degradative autophagy is probably a negative for most viruses, initiating nondegradative autophagic membranes benefits a wide variety of viruses.

Microbiota therapeutics for inflammatory bowel disease: the way forward

Microbiota therapeutics that transplant faecal material from healthy donors to people with mild-to-moderate ulcerative colitis have shown the potential to induce remission in about 30% of participants in small, phase 2 clinical trials. Despite this substantial achievement, the field needs to leverage the insights gained from these trials and progress towards phase 3 clinical trials and drug approval, while identifying the distinct clinical niche for this new therapeutic modality within inflammatory bowel disease (IBD) therapeutics. We describe the lessons that can be learned from past studies of microbiota therapeutics, from full spectrum donor stool to defined products manufactured in vitro. We explore the actionable insights these lessons provide on the design of near-term studies and future trajectories for the integration of microbiota therapeutics in the treatment of IBD. If successful, microbiota therapeutics will provide a powerful orthogonal approach (complementing or in combination with existing immunomodulatory drugs) to raise the therapeutic ceiling for the many non-responders and partial responders within the IBD patient population.

Approach to a Child with Chronic Diarrhea

Chronic diarrhea in children is challenging both with regards to etiological diagnosis and for management. Etiology and pathophysiological mechanisms vary widely from neonates to adolescents. Congenital or genetic causes are more frequent in neonates, while infections, allergy and immune-mediated mechanisms are more frequent in childhood. A thorough history and proper physical examination are required to decide for further diagnostic evaluation. The approach to a child with chronic diarrhea should be age specific and based predominantly on the pathophysiological mechanism involved. The nature of the stool like watery, bloody or fatty (steatorrhea) can suggest the probable etiology and organ system involved. After routine tests, evaluation with specific serological tests, imaging, endoscopy (gastroscopy/colonoscopy), histopathology of intestinal mucosa, breath tests or radionuclide imaging may be required to make a definitive diagnosis. Genetic evaluation is important in congenital diarrheas, monogenic inflammatory bowel disease (IBD) and immunodeficiency disorders. Management is aimed at stabilization, nutritional support and etiology specific treatment. Specific therapy can be as simple as exclusion of specific nutrient or as complicated as small bowel transplant. Evaluation and management require expertise and thus patients need to be referred in a timely fashion. This will minimise morbidity including nutritional consequences and improve outcome.

Associations of Eosinophilic Gastrointestinal Disorders with Other Gastrointestinal and Allergic Diseases

Eosinophilic gastrointestinal disorders (EGIDs) are becoming more common causing significant suffering and reduced quality of life. These conditions can affect different parts of the digestive system, either individually or in combination. Recognition of their link to allergic disorders or other gastrointestinal (GI) diseases has raised questions about their shared underlying mechanisms, which has had implications for diagnosis and management. The authors critically examine the current understanding of the connection between EGIDs and allergic conditions (ie, atopic dermatitis, allergic rhinitis, asthma, and food allergy) and GI diseases (ie, inflammatory bowel disease, celiac disease, gastroesophageal reflux disease, and motility disorders).

Genetic mapping across autoimmune diseases reveals shared associations and mechanisms

Autoimmune and inflammatory diseases are polygenic disorders of the immune system. Many genomic loci harbor risk alleles for several diseases, but the limited resolution of genetic mapping prevents determining whether the same allele is responsible, indicating a shared underlying mechanism. Here, using a collection of 129,058 cases and controls across 6 diseases, we show that ~40% of overlapping associations are due to the same allele. We improve fine-mapping resolution for shared alleles twofold by combining cases and controls across diseases, allowing us to identify more expression quantitative trait loci driven by the shared alleles. The patterns indicate widespread sharing of pathogenic mechanisms but not a single global autoimmune mechanism. Our approach can be applied to any set of traits and is particularly valuable as sample collections become depleted.

Transition care in patients with IBD: The pediatric and the adult gastroenterologist's perspective. Results from a national survey

BACKGROUND

Transition is a crucial process in the care of IBD patients, although it remains largely heterogeneous.

AIMS

To provide an overview of the transition process in Italy and to investigate the perspective of the paediatric and adult physicians.

METHODS

An online survey was developed by the Italian Group for Inflammatory Bowel Diseases (IG-IBD) and the Italian Society of Paediatric Gastroenterology, Hepatology and Nutrition (SIGENP).

RESULTS

104 physicians (62 paediatric and 42 adult gastroenterologists) participated to the survey. The disease status was ranked with the highest priority among the key elements of the transition process. The age of the patient was perceived with a higher priority by paediatric gastroenterologists than by adult ones (p < 0.01). In most cases, the transition was organized through one or more joint meetings. Only less than 25 % of responders reported to involve other professions during transition. The struggle in leaving paediatric setting was perceived as the main obstacle to an effective transition process. Paediatric IBD gastroenterologists ranked the struggle in leaving the paediatric setting and the attending physician as higher critical point than adult gastroenterologists.

CONCLUSIONS

The current survey provided a snapshot of the IBD transition process in Italy. The present findings highlight the need to embed transitional care in healthcare policy.

STAT1 Mutations in Chronic Mucocutaneous Candidiasis Diagnosed in an Adult

A 30-year-old man presented with oral candidiasis and a history of lung abscess. He experienced recurring oral and skin candidiasis in childhood but spent long periods without any infections. Therefore, immunodeficiency was suspected. T and B lymphocyte and natural killer cell counts as well as immunoglobulin levels were normal. Human immunodeficiency virus test results were negative. Therefore, we suspected chronic mucocutaneous candidiasis (CMC). The signal transducer and activator of transcription (STAT) mutation, the leading cause of CMC, was detected by exome sequencing. Most cases of STAT1 mutations are diagnosed in childhood, but a few are diagnosed in adulthood because Candida infections may not be severe.

Sialylated glycoproteins and sialyltransferases in digestive cancers: Mechanisms, diagnostic biomarkers, and therapeutic targets

Sialic acid (SA), as the ultimate epitope of polysaccharides, can act as a cap at the end of polysaccharide chains to prevent their overextension. Sialylation is the enzymatic process of transferring SA residues onto polysaccharides and is catalyzed by a group of enzymes known as sialyltransferases (SiaTs). It is noteworthy that the sialylation level of glycoproteins is significantly altered when digestive cancer occurs. And this alteration exhibits a close correlation with the progression of these cancers. In this review, from the perspective of altered SiaTs expression levels and changed glycoprotein sialylation patterns, we summarize the pathogenesis of gastric cancer (GC), colorectal cancer (CRC), pancreatic ductal adenocarcinoma (PDAC), and hepatocellular carcinoma (HCC). Furthermore, we propose potential early diagnostic biomarkers and prognostic indicators for different digestive cancers. Finally, we summarize the therapeutic value of sialylation in digestive system cancers.

Inflammatory bowel disease and allergic diseases: A Mendelian randomization study

BACKGROUND

Inflammatory bowel disease (IBD) and allergic diseases possess similar genetic backgrounds and pathogenesis. Observational studies have shown a correlation, but the exact direction of cause and effect remains unclear. The aim of this Mendelian randomization (MR) study is to assess bidirectional causality between inflammatory bowel disease and allergic diseases.

METHOD

We comprehensively analyzed the causal relationship between inflammatory bowel disease (IBD), Crohn's disease (CD), ulcerative colitis (UC) and allergic disease (asthma, Hay fever, and eczema) as a whole, allergic conjunctivitis (AC), atopic dermatitis (AD), allergic asthma (AAS), and allergic rhinitis (AR) by performing a bidirectional Mendelian randomization study using summary-level data from genome-wide association studies. The analysis results mainly came from the random-effects model of inverse variance weighted (IVW-RE). In addition, multivariate Mendelian randomization (MVMR) analysis was conducted to adjust the effect of body mass index (BMI) on the instrumental variables.

RESULTS

The IVW-RE method revealed that IBD genetically increased the risk of allergic disease as a whole (OR = 1.03, 95% CI = 1.01-1.04, fdr.p = .015), AC (OR = 1.04, 95% CI = 1.01-1.06, fdr.p = .011), and AD (OR = 1.06, 95% CI = 1.02-1.09, fdr.p = .004). Subgroup analysis further confirmed that CD increased the risk of allergic disease as a whole (OR = 1.02, 95% CI = 1.00-1.03, fdr.p = .031), AC (OR = 1.03, 95% CI = 1.01-1.05, fdr.p = .012), AD (OR = 1.06, 95% CI = 1.02-1.09, fdr.p = 2E-05), AAS (OR = 1.05, 95% CI = 1.02-1.08, fdr.p = .002) and AR (OR = 1.03, 95% CI = 1.00-1.07, fdr.p = .025), UC increased the risk of AAS (OR = 1.02, 95% CI = 0.98-1.07, fdr.p = .038). MVMR results showed that after taking BMI as secondary exposure, the causal effects of IBD on AC, IBD on AD, CD on allergic disease as a whole, CD on AC, CD on AD, CD on AAS, and CD on AR were still statistically significant. No significant association was observed in the reverse MR analysis.

CONCLUSION

This Mendelian randomized study demonstrated that IBD is a risk factor for allergic diseases, which is largely attributed to its subtype CD increasing the risk of AC, AD, ASS, and AR. Further investigations are needed to explore the causal relationship between allergic diseases and IBD.

An update on dietary therapies in paediatric Crohn's disease

PURPOSE OF REVIEW

This article provides a literature update on original articles published in the past 18 months (May 2022-November 2023) in the dietary management of paediatric Crohn's disease.

RECENT FINDINGS

There is more data to support the use of exclusive enteral nutrition in the management of active Crohn's disease in children. Several food-based dietary therapies have been proposed for the management of Crohn's disease. There is an interest in precision nutritional therapy in Crohn's disease, but current data are scarce.

SUMMARY

Exclusive enteral nutrition is an effective treatment for paediatric Crohn's disease. Predictors of response to exclusive enteral nutrition include mild disease phenotype and ileal disease involvement, although data remain inconclusive. Adherence to exclusive enteral nutrition is cornerstone to its efficacy. Treatment with exclusive enteral nutrition modifies the gut microbiome, modulates bile acid metabolism and has significant effects on host immune responses. More studies are expected in which drugs need to be combined with dietary therapies and microbial therapeutics. The efficacy of Crohn's disease exclusion diet coupled with partial enteral nutrition is supported by independent studies, but tolerance remains an issue, particularly for long-term disease management. More research is anticipated in precision nutritional therapy in paediatric Crohn's disease, but currently no recommendations can be made.

Blood-testis barrier: a review on regulators in maintaining cell junction integrity between Sertoli cells

The blood-testis barrier (BTB) is formed adjacent to the seminiferous basement membrane. It is a distinct ultrastructure, partitioning testicular seminiferous epithelium into apical (adluminal) and basal compartments. It plays a vital role in developing and maturing spermatocytes into spermatozoa via reorganizing its structure. This enables the transportation of preleptotene spermatocytes across the BTB, from basal to adluminal compartments in the seminiferous tubules. Several bioactive peptides and biomolecules secreted by testicular cells regulate the BTB function and support spermatogenesis. These peptides activate various downstream signaling proteins and can also be the target themself, which could improve the diffusion of drugs across the BTB. The gap junction (GJ) and its coexisting junctions at the BTB maintain the immunological barrier integrity and can be the "gateway" during spermatocyte transition. These junctions are the possible route for toxicant entry, causing male reproductive dysfunction. Herein, we summarize the detailed mechanism of all the regulators playing an essential role in the maintenance of the BTB, which will help researchers to understand and find targets for drug delivery inside the testis.

The Effect of Polymorphisms and Other Biomarkers on Infliximab Exposure in Paediatric Inflammatory Bowel Disease: Development of a Population Pharmacokinetic Model

BACKGROUND

Therapeutic drug monitoring (TDM) of infliximab has been shown to be a effective strategy for inflammatory bowel disease (IBD). Population pharmacokinetic (PopPK) modeling can predict trough concentrations for individualized dosing.

OBJECTIVE

The aim of this study was to develop a PopPK model of infliximab in a paediatric population with IBD, assessing the effect of single nucleotide polymorphisms (SNPs) and other biomarkers on infliximab clearance.

METHODS

This observational and ambispective single-centre study was conducted in paediatric patients with IBD treated with infliximab between July 2016 and July 2022 in the Paediatric Gastroenterology Service of the Hospital Universitari Vall d'Hebron (HUVH) (Spain). Demographic, clinical, and analytical variables were collected. Twenty SNPs potentially associated with variations in the response to infliximab plasma concentrations were analysed. infliximab serum concentrations and antibodies to infliximab (ATI) were determined by ELISA. PopPK modelling was performed using nonlinear mixed-effects analysis (NONMEM).

RESULTS

Thirty patients (21 males) were included. The median age (range) at the start of infliximab treatment was 13 years (16 months to 16 years). A total of 190 samples were obtained for model development (49 [25.8%] during the induction phase). The pharmacokinetics (PK) of infliximab were described using a two-compartment model. Weight, erythrocyte sedimentation rate (ESR), faecal calprotectin (FC), and the SNP rs1048610 (ADAM17) showed statistical significance for clearance (CL), and albumin for inter-compartmental clearance (Q). Estimates of CL1 (genotype 1-AA), CL2 (genotype 2-AG), CL3 (genotype 3-GG), Q, Vc, and Vp (central and peripheral distribution volumes) were 0.0066 L/h/46.4 kg, 0.0055 L/h/46.4 kg, 0.0081 L/h/46.4 kg, 0.0029 L/h/46.4 kg, 0.6750 L/46.4 kg, and 1.19 L/46.4 kg, respectively. The interindividual variability (IIV) estimates for clearance, Vc, and Vp were 19.33, 16.42, and 36.02%, respectively.

CONCLUSIONS

A popPK model utilising weight, albumin, FC, ESR, and the SNP rs1048610 accurately predicted infliximab trough concentrations in children with IBD.

Clostridioides difficile infection in inflammatory bowel disease: a clinical review

INTRODUCTION

Strong clinical data demonstrate that inflammatory bowel disease (IBD) is an independent risk factor for Clostridiodes difficile infection (CDI) and suggest a globally increased prevalence and severity of C. difficile coinfection in IBD patients (CDI-IBD). In addition to elderly individuals, children are also at higher risk of CDI-IBD. Rapid diagnosis is essential since the clinical manifestations of active IBD and CDI-IBD are indistinguishable. Antibiotics have been well established in the treatment of CDI-IBD, but they do not prevent recurrence.

AREAS COVERED

Herein, the authors focus on reviewing recent research advances on the new therapies of CDI-IBD. The novel therapies include gut microbiota restoration therapies (such as prebiotics, probiotics and FMT), immunotherapy (such as vaccines and monoclonal antibodies) and diet strategies (such as groningen anti-inflammatory diet and mediterranean diet). Future extensive prospective and placebo-controlled studies are required to evaluate their efficacy and long-term safety.

EXPERT OPINION

Available studies show that the prevalence of CDI-IBD is not optimistic. Currently, potential treatment options for CDI-IBD include a number of probiotics and novel antibiotics. This review updates the knowledge on the management of CDI in IBD patients, which is timely and important for GI doctors and scientists.

Deep learning-based lesion detection and severity grading of small-bowel Crohn's disease ulcers on double-balloon endoscopy images

BACKGROUND AND AIMS

Double-balloon endoscopy (DBE) is widely used in diagnosing small-bowel Crohn's disease (CD). However, CD misdiagnosis frequently occurs if inexperienced endoscopists cannot accurately detect the lesions. The CD evaluation may also be inaccurate owing to the subjectivity of endoscopists. This study aimed to use artificial intelligence (AI) to accurately detect and objectively assess small-bowel CD for more refined disease management.

METHODS

We collected 28,155 small-bowel DBE images from 628 patients from January 2018 to December 2022. Four expert gastroenterologists labeled the images, and at least 2 endoscopists made the final decision with agreement. A state-of-the-art deep learning model, EfficientNet-b5, was trained to detect CD lesions and evaluate CD ulcers. The detection included lesions of ulcer, noninflammatory stenosis, and inflammatory stenosis. Ulcer grading included ulcerated surface, ulcer size, and ulcer depth. A comparison of AI model performance with endoscopists was performed.

RESULTS

The EfficientNet-b5 achieved high accuracies of 96.3% (95% confidence interval [CI], 95.7%-96.7%), 95.7% (95% CI, 95.1%-96.2%), and 96.7% (95% CI, 96.2%-97.2%) for the detection of ulcers, noninflammatory stenosis, and inflammatory stenosis, respectively. In ulcer grading, the EfficientNet-b5 exhibited average accuracies of 87.3% (95% CI, 84.6%-89.6%) for grading the ulcerated surface, 87.8% (95% CI, 85.0%-90.2%) for grading the size of ulcers, and 85.2% (95% CI, 83.2%-87.0%) for ulcer depth assessment.

CONCLUSIONS

The EfficientNet-b5 achieved high accuracy in detecting CD lesions and grading CD ulcers. The AI model can provide expert-level accuracy and objective evaluation of small-bowel CD to optimize the clinical treatment plans.

Reverse-engineered exclusive enteral nutrition in pediatric Crohn's disease: A pilot trial

BACKGROUND

In pediatric Crohn's disease (CD), commercial formulas used as exclusive enteral nutrition (EEN) are effective at inducing remission. This study aims to assess the impact of a whole-food blended smoothie as EEN on CD activity and the intestinal microbiome.

METHODS

A 4-week prospective trial assessed the impact of EEN with a whole-food smoothie on newly diagnosed mild-to-moderate active pediatric CD. The smoothie with a multivitamin were developed to meet age-appropriate nutritional requirements. Assessment over 4 weeks included Pediatric Crohn's Disease Activity Index (PCDAI), serum laboratories, fecal calprotectin (FCP), and stool collection for metagenomic shotgun sequencing and microbiota composition analysis. Clinical remission was defined as PCDAI ≤ 10 at week 4.

RESULTS

Ten participants were enrolled with median age 14.5 years, and 8 completed the trial. Baseline mean PCDAI was 26.3 ± 9.1 and mean FCP 1149 ± 718 µg/g. At week 4, 80% of participants achieved clinical remission. FCP decreased by over half in 60% of participants, with FCP below 250 µg/g in 60% and below 100 µg/g in 40%. Microbiome analysis showed a significant increase in species richness over 4 weeks (p = 0.01). Compared to baseline, the relative abundance at week 2 and at week 4 was significantly increased for Bifidobacterium and Streptococcus and decreased for Blautia (p < 0.05 for all).

CONCLUSION

A whole-food blended smoothie was effective for inducing clinical remission and decreasing FCP in pediatric CD similar to commercial EEN formulas. Further research may give insight into data-driven whole-food dietary approaches for CD management.

CLINICALTRIALS

gov NCT03508193.

Inflammatory Bowel Disease in Children

Inflammatory bowel disease is an important cause of chronic diarrhea in children, with a rising incidence, globally. The two main subtypes include Crohn's disease and ulcerative colitis. The clinical features are variable, and diagnosis requires initial first-line investigations followed by the involvement of specialist input for targeted imaging and endoscopy with biopsy, to confirm the diagnosis. Despite detailed investigation, inflammatory bowel disease may be clinically indistinguishable from chronic infections such as intestinal tuberculosis, and anti-tuberculosis treatment may be considered prior to further management considerations. The medical management of inflammatory bowel disease depends on subtype classification and severity, and may involve a step-wise approach to immunosuppressive therapies. In children, the consequences of poorly controlled disease are wide ranging, from psychosocial impacts and school non-attendance, to growth impairment and pubertal delay with subsequent impacts on bone health. In addition, an increased need for hospitalization and surgical intervention, and ultimately risk of cancer long-term. A multi-disciplinary team with expertise in inflammatory bowel disease is recommended to mitigate these risks and help to achieve the goal of sustained remission with endoscopic healing. This review focuses on updates on best clinical practice on the diagnosis and management of inflammatory bowel disease in children.