Single-cell, single-nucleus, and spatial transcriptomics characterization of the immunological landscape in the healthy and PSC human liver.

BACKGROUND & AIMS: Primary sclerosing cholangitis (PSC) is an immune-mediated cholestatic liver disease for which there is an unmet need to understand the cellular composition of the affected liver and how it underlies disease pathogenesis. We aimed to generate a comprehensive atlas of the PSC liver using multi-omic modalities and protein-based functional validation. METHODS: We employed single-cell and single-nucleus RNA sequencing (47,156 cells and 23,000 nuclei) and spatial transcriptomics (one sample by 10x Visium and five samples with Nanostring GeoMx DSP) to profile the cellular ecosystem in 10 PSC livers. Transcriptomic profiles were compared to 24 neurologically deceased donor livers (107,542 cells) and spatial transcriptomics controls, as well as 18,240 cells and 20,202 nuclei from three PBC livers. Flow cytometry was performed to validate PSC-specific differences in immune cell phenotype and function. RESULTS: PSC explants with parenchymal cirrhosis and prominent periductal fibrosis contained a population of cholangiocyte-like hepatocytes that were surrounded by diverse immune cell populations. PSC-associated biliary, mesenchymal, and endothelial populations expressed chemokine and cytokine transcripts involved in immune cell recruitment. Additionally, expanded CD4+ T cells and recruited myeloid populations in the PSC liver expressed the corresponding receptors to these chemokines and cytokines, suggesting potential recruitment. Tissue-resident macrophages, by contrast, were reduced in number and exhibited a dysfunctional and downregulated inflammatory response to lipopolysaccharide and interferon-γ stimulation. CONCLUSIONS: We present a comprehensive atlas of the PSC liver and demonstrate an exhaustion-like phenotype of myeloid cells and markers of chronic cytokine expression in late-stage PSC lesions. This atlas expands our understanding of the cellular complexity of PSC and has potential to guide the development of novel treatments. IMPACT AND IMPLICATIONS: Primary sclerosing cholangitis (PSC) is a rare liver disease characterized by chronic inflammation and irreparable damage to the bile ducts, which eventually results in liver failure. Due to a limited understanding of the underlying pathogenesis of disease, treatment options are limited. To address this, we sequenced healthy and diseased livers to compare the activity, interactions, and localization of immune and non-immune cells. This revealed that hepatocytes lining PSC scar regions co-express cholangiocyte markers, whereas immune cells infiltrate the scar lesions. Of these cells, macrophages, which typically contribute to tissue repair, were enriched in immunoregulatory genes and demonstrated a lack of responsiveness to stimulation. These cells may be involved in maintaining hepatic inflammation and could be a target for novel therapies.

Primary sclerosing cholangitis and overlap features of autoimmune hepatitis: A coming of age or an age-ist problem?

Autoimmune liver diseases are siloed into three syndromes that define clinical practice. These classifiers can, and are, challenged by variant presentations across all ages, something inevitable to disease definitions that rely on interpreting (inherently variable) semi-quantitative/qualitative clinical, laboratory, pathological or radiological findings. Furthermore this categorisation is premised on an ongoing absence of definable disease aetiologies. Clinicians thus encounter individuals with biochemical, serological, and histological manifestations that are common to both primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH), often labelled as 'PSC/AIH-overlap'. In childhood the term 'autoimmune sclerosing cholangitis (ASC)' may be used, and some propose this to be a distinct disease process. In this article we champion the concept that ASC and PSC/AIH-overlap are not distinct entities. Rather, they represent inflammatory phases of PSC frequently manifesting earlier in the disease course, most notably in younger patients. Ultimately, disease outcomes remain similar to those of a more classical PSC phenotype observed in later life. Thus, we argue that it is now time to align disease names and descriptions used by clinicians across all patient subpopulations, to help unify care. This will enhance collaborative studies and ultimately contribute to rational treatment advances.

Evolving Short- and Long-Term Goals of Management of Inflammatory Bowel Diseases: Getting It Right, Making It Last.

Short- and long-term treatment targets in inflammatory bowel diseases (IBDs) evolved during the last decade, shifting from symptom control to endoscopic healing and patient-centered parameters. The STRIDE-II consensus placed these targets on a timeline from initiating treatment and introduced additional targets, normalization of serum and fecal biomarkers, restoration of quality of life, prevention of disability, and, in children, restoration of growth. Transmural healing in Crohn's disease and histologic healing in ulcerative colitis currently serve as adjunct measures to gauge remission depth. However, whether early treatment according to a treat-to-target paradigm affects the natural course of IBD remains unclear, leading to the need for prospective disease-modification trials. The SPIRIT consensus defined the targets for these trials to assess the long-term impact of early treatment on quality of life, disability, disease complications, risk of neoplastic lesions, and mortality. As further data emerge about the risk-benefit balance of aiming toward deeper healing, the targets in treating IBDs may continue to shift.

ADALIMUMAB VERSUS INFLIXIMAB IN LUMINAL PEDIATRIC CROHN'S DISEASE: COMPARABLE OUTCOMES IN A PROSPECTIVE MULTICENTER COHORT STUDY.

BACKGROUND: This study compared real-world effectiveness between adalimumab (ADA) and infliximab (IFX) in children with Crohn's disease (CD). METHODS: Children enrolled into the prospective Canadian Children Inflammatory Bowel Disease Network (CIDsCaNN) National Inception Cohort between 2014 and 2020 who commenced ADA or IFX as first anti-tumor necrosis factor (antiTNF) agent for luminal CD were included. Multivariate logistic regression modelled the propensity of commencing ADA; propensity score matching was used to match IFX-treated children to ADA-treated children. The primary outcome at one year was steroid-free clinical remission (SFCR). Secondary outcomes at one year were I) combined SFCR and c-reactive protein (CRP) remission; II) treatment intensification; and III) antiTNF durability. Odds ratios (aOR) and hazard ratio (aHR) adjusted for concomitant immunomodulator use with 95% confidence interval (CI) are reported. RESULTS: In the propensity score matched cohort of 147 ADA-treated and 147 IFX-treated children, 92 (63%) ADA- and 87 (59%) IFX-treated children achieved SFCR at one year (aOR: 1.4, 95% CI 0.9-2.4); 75 of 140 (54%) ADA- and 85 of 144 (59%) IFX-treated children achieved combined SFCR and CRP remission (aOR: 1.0, 95% CI 0.6-1.6). ADA-treated children less frequently underwent treatment intensification (21 [14%]) compared to IFX-treated children (69 [47%]) (P<0.0001). Discontinuation of antiTNF occurred in 18 (12%) ADA-treated and 15 (10%) IFX-treated children (aHR: 1.2, 95% CI 0.6-2.2). CONCLUSION: Children with Crohn's disease achieved favourable outcomes at one year with either ADA or IFX as first antiTNF agents. Those receiving IFX did not have significantly superior outcomes compared to clinically similar children receiving ADA.

STRIDE-II: An Update on the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) Initiative of the International Organization for the Study of IBD (IOIBD): Determining Therapeutic Goals for Treat-to-Target strategies in IBD.

BACKGROUND: The Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) initiative of the International Organization for the Study of Inflammatory Bowel Diseases (IOIBD) has proposed treatment targets in 2015 for adult patients with inflammatory bowel disease (IBD). We aimed to update the original STRIDE statements for incorporating treatment targets in both adult and pediatric IBD. METHODS: Based on a systematic review of the literature and iterative surveys of 89 IOIBD members, recommendations were drafted and modified in 2 surveys and 2 voting rounds. Consensus was reached if ≥75% of participants scored the recommendation as 7 to 10 on a 10-point rating scale. RESULTS: In the systematic review, 11,278 manuscripts were screened, of which 435 were included. The first IOIBD survey identified the following targets as most important: clinical response and remission, endoscopic healing, and normalization of C-reactive protein/erythrocyte sedimentation rate and calprotectin. Fifteen recommendations were identified, of which 13 were endorsed. STRIDE-II confirmed STRIDE-I long-term targets of clinical remission and endoscopic healing and added absence of disability, restoration of quality of life, and normal growth in children. Symptomatic relief and normalization of serum and fecal markers have been determined as short-term targets. Transmural healing in Crohn's disease and histological healing in ulcerative colitis are not formal targets but should be assessed as measures of the remission depth. CONCLUSIONS: STRIDE-II encompasses evidence- and consensus-based recommendations for treat-to-target strategies in adults and children with IBD. This frameworkshould be adapted to individual patients and local resources to improve outcomes.

Predicting Outcomes in Pediatric Ulcerative Colitis for Management Optimization: Systematic Review and Consensus Statements From the Pediatric Inflammatory Bowel Disease-Ahead Program.

BACKGROUND & AIMS: A better understanding of prognostic factors in ulcerative colitis (UC) could improve patient management and reduce complications. We aimed to identify evidence-based predictors for outcomes in pediatric UC, which may be used to optimize treatment algorithms. METHODS: Potential outcomes worthy of prediction in UC were determined by surveying 202 experts in pediatric UC. A systematic review of the literature, with selected meta-analysis, was performed to identify studies that investigated predictors for these outcomes. Multiple national and international meetings were held to reach consensus on evidence-based statements. RESULTS: Consensus was reached on 31 statements regarding predictors of colectomy, acute severe colitis (ASC), chronically active pediatric UC, cancer and mortality. At diagnosis, disease extent (6 studies, N = 627; P = .035), Pediatric Ulcerative Colitis Activity Index score (4 studies, n = 318; P < .001), hemoglobin, hematocrit, and albumin may predict colectomy. In addition, family history of UC (2 studies, n = 557; P = .0004), extraintestinal manifestations (4 studies, n = 526; P = .048), and disease extension over time may predict colectomy, whereas primary sclerosing cholangitis (PSC) may be protective. Acute severe colitis may be predicted by disease severity at onset and hypoalbuminemia. Higher Pediatric Ulcerative Colitis Activity Index score and C-reactive protein on days 3 and 5 of hospital admission predict failure of intravenous steroids. Risk factors for malignancy included concomitant diagnosis of primary sclerosing cholangitis, longstanding colitis (>10 years), male sex, and younger age at diagnosis. CONCLUSIONS: These evidence-based consensus statements offer predictions to be considered for a personalized medicine approach in treating pediatric UC.

Predicting Outcomes in Pediatric Crohn's Disease for Management Optimization: Systematic Review and Consensus Statements From the Pediatric Inflammatory Bowel Disease-Ahead Program.

BACKGROUND & AIMS: A better understanding of prognostic factors within the heterogeneous spectrum of pediatric Crohn's disease (CD) should improve patient management and reduce complications. We aimed to identify evidence-based predictors of outcomes with the goal of optimizing individual patient management. METHODS: A survey of 202 experts in pediatric CD identified and prioritized adverse outcomes to be avoided. A systematic review of the literature with meta-analysis, when possible, was performed to identify clinical studies that investigated predictors of these outcomes. Multiple national and international face-to-face meetings were held to draft consensus statements based on the published evidence. RESULTS: Consensus was reached on 27 statements regarding prognostic factors for surgery, complications, chronically active pediatric CD, and hospitalization. Prognostic factors for surgery included CD diagnosis during adolescence, growth impairment, NOD2/CARD15 polymorphisms, disease behavior, and positive anti-Saccharomyces cerevisiae antibody status. Isolated colonic disease was associated with fewer surgeries. Older age at presentation, small bowel disease, serology (anti-Saccharomyces cerevisiae antibody, antiflagellin, and OmpC), NOD2/CARD15 polymorphisms, perianal disease, and ethnicity were risk factors for penetrating (B3) and/or stenotic disease (B2). Male sex, young age at onset, small bowel disease, more active disease, and diagnostic delay may be associated with growth impairment. Malnutrition and higher disease activity were associated with reduced bone density. CONCLUSIONS: These evidence-based consensus statements offer insight into predictors of poor outcomes in pediatric CD and are valuable when developing treatment algorithms and planning future studies. Targeted longitudinal studies are needed to further characterize prognostic factors in pediatric CD and to evaluate the impact of treatment algorithms tailored to individual patient risk.

Recurrence of Primary Sclerosing Cholangitis After Liver Transplant in Children: An International Observational Study.

BACKGROUND AND AIMS: Recurrent primary sclerosing cholangitis (rPSC) following liver transplant (LT) has a negative impact on graft and patient survival; little is known about risk factors for rPSC or disease course in children. APPROACH AND RESULTS: We retrospectively evaluated risk factors for rPSC in 140 children from the Pediatric PSC Consortium, a multicenter international registry. Recipients underwent LT for PSC and had >90 days of follow-up. The primary outcome, rPSC, was defined using Graziadei criteria. Median follow-up after LT was 3 years (interquartile range 1.1-6.1). rPSC occurred in 36 children, representing 10% and 27% of the subjects at 2 years and 5 years following LT, respectively. Subjects with rPSC were younger at LT (12.9 vs. 16.2 years), had faster progression from PSC diagnosis to LT (2.5 vs. 4.1 years), and had higher alanine aminotransferase (112 vs. 66 IU/L) at LT (all P < 0.01). Inflammatory bowel disease was more prevalent in the rPSC group (86% vs. 66%; P = 0.025). After LT, rPSC subjects had more episodes of biopsy-proved acute rejection (mean 3 vs. 1; P < 0.001), and higher prevalence of steroid-refractory rejection (41% vs. 20%; P = 0.04). In those with rPSC, 43% developed complications of portal hypertension, were relisted for LT, or died within 2 years of the diagnosis. Mortality was higher in the rPSC group (11.1% vs. 2.9%; P = 0.05). CONCLUSIONS: The incidence of rPSC in this cohort was higher than previously reported, and was associated with increased morbidity and mortality. Patients with rPSC appeared to have a more aggressive, immune-reactive phenotype. These findings underscore the need to understand the immune mechanisms of rPSC, to lay the foundation for developing new therapies and improve outcomes in this challenging population.

Oral Vancomycin, Ursodeoxycholic Acid, or No Therapy for Pediatric Primary Sclerosing Cholangitis: A Matched Analysis.

BACKGROUND AND AIMS: Many children with primary sclerosing cholangitis (PSC) receive oral vancomycin therapy (OVT) or ursodeoxycholic acid (UDCA). There is a paucity of data on whether these medications improve outcomes. APPROACH AND RESULTS: We analyzed retrospective data from the Pediatric PSC Consortium. Children treated with OVT were matched 1:1:1 to those treated with UDCA or managed with observation (no treatment) based on the closest propensity score, ensuring similar baseline characteristics. Two hundred sixty-four patients (88 each with OVT, UDCA, or observation) had matching propensity scores and were similar in demographics, phenotype, immunosuppression, baseline biochemistry, and hepatic fibrosis. After 1 year in an intention-to-treat analysis, all outcome metrics were similar regardless of treatment group. In OVT, UDCA, and untreated groups, respectively: Gamma-glutamyltransferase normalized in 53%, 49%, and 52% (P = not significant [NS]), liver fibrosis stage was improved in 20%, 13%, and 18% and worsened in 11%, 29%, and 18% (P = NS), and the 5-year probability of liver transplant listing was 21%, 10%, and 12% (P = NS). Favorable outcome was associated with having a mild phenotype of PSC and minimal hepatic fibrosis. CONCLUSIONS: We presented the largest-ever description of outcomes on OVT in PSC and compared them to carefully matched patients on UDCA or no therapy. Neither OVT nor UDCA showed improvement in outcomes compared to a strategy of observation. Patients progressed to end-stage liver disease at similar rates. Spontaneous normalization of biochemistry is common in children receiving no therapy, particularly in the majority of children with a mild phenotype and an early stage of disease. Placebo-controlled treatment trials are needed to identify effective treatments for pediatric PSC.

The Sclerosing Cholangitis Outcomes in Pediatrics (SCOPE) Index: A Prognostic Tool for Children.

BACKGROUND AND AIMS: Disease progression in children with primary sclerosing cholangitis (PSC) is variable. Prognostic and risk-stratification tools exist for adult-onset PSC, but not for children. We aimed to create a tool that accounts for the biochemical and phenotypic features and early disease stage of pediatric PSC. APPROACH AND RESULTS: We used retrospective data from the Pediatric PSC Consortium. The training cohort contained 1,012 patients from 40 centers. We generated a multivariate risk index (Sclerosing Cholangitis Outcomes in Pediatrics [SCOPE] index) that contained total bilirubin, albumin, platelet count, gamma glutamyltransferase, and cholangiography to predict a primary outcome of liver transplantation or death (TD) and a broader secondary outcome that included portal hypertensive, biliary, and cancer complications termed hepatobiliary complications (HBCs). The model stratified patients as low, medium, or high risk based on progression to TD at rates of <1%, 3%, and 9% annually and to HBCs at rates of 2%, 6%, and 13% annually, respectively (P < 0.001). C-statistics to discriminate outcomes at 1 and 5 years were 0.95 and 0.82 for TD and 0.80 and 0.76 for HBCs, respectively. Baseline hepatic fibrosis stage was worse with increasing risk score, with extensive fibrosis in 8% of the lowest versus 100% with the highest risk index (P < 0.001). The model was validated in 240 children from 11 additional centers and performed well. CONCLUSIONS: The SCOPE index is a pediatric-specific prognostic tool for PSC. It uses routinely obtained, objective data to predict a complicated clinical course. It correlates strongly with biopsy-proven liver fibrosis. SCOPE can be used with families for shared decision making on clinical care based on a patient's individual risk, and to account for variable disease progression when designing future clinical trials.

Long-Term Outcomes With Adalimumab Therapy in Pediatric Crohn Disease: Associations With Adalimumab Exposure.

BACKGROUND/AIMS: Pediatric Crohn disease (CD) treatment goals have evolved. Among children receiving adalimumab (ADA) we examined long-term durability of clinical remission, linear growth, and associations of trough concentration (TC) with biomarker, endoscopic and imaging outcomes. METHODS: Single-center retrospective study. Pediatric CD activity index, C-reactive protein, fecal calprotectin, and height measured longitudinally. Discontinuation due to secondary loss of response (LOR) was assessed using Cox proportional hazards model. Associations between TC and clinical and biomarker remission, endoscopic and magnetic resonance imaging (MRI) improvements were assessed using Cox regression with time-dependent covariates. RESULTS: Between January 2007 and June 2018, 213 children (median age 14.1 years (interquartile range [IQR] 12.5-15.7) 65% males) initiated ADA. One hundred and seventy-four (82%) achieved clinical remission (PCDAI < 10). During 24.8 (IQR 15.6-38.4) months follow-up, 26 (15%) discontinued ADA due to LOR, and 10 (6%) due to adverse events. Being anti-tumor necrosis factor (TNF) naïve and inflammatory behavior associated with increased likelihood of clinical remission (odds ratio [OR] 2.39, P = 0.033, and 3.13, P = 0.013, respectively) and with decreased LOR (hazard ratio [HR] 0.3, P = 0.002, and HR 0.35, P = 0.01, respectively). Cumulative LOR among 135 anti-TNF naïve patients: 0%, 8%, 15% within 1, 2, 3 years, similarly durable with mono- and immunomodulator combination therapy. Among pre-/early pubertal children mean height (-0.82) normalized to -0.07. TC consistently >7.5 ug/mL was associated with durable clinical remission (HR = 17.24, P < 0.001); TC >10 ug/mL with durable biomarker remission (HR = 6.56, P < 0.001) and endoscopic (OR 10.4, P = 0.002) and MRI (OR 7.6, P = 0.001) improvements. CONCLUSION: ADA monotherapy maintains durable clinical remission. Biomarker remission, mucosal and transmural improvements were associated with greater ADA exposure.

Vitamin D deficiency enhances expression of autophagy-regulating miR-142-3p in mouse and "involved" IBD patient intestinal tissues.

Vitamin D deficiency is an environmental factor involved in the pathogenesis of inflammatory bowel disease (IBD); however, the mechanisms surrounding its role remain unclear. Previous studies conducted in an intestinal epithelial-specific vitamin D receptor (VDR) knockout model suggest that a lack of vitamin D signaling causes a reduction in intestinal autophagy. A potential link between vitamin D deficiency and dysregulated autophagy is microRNA (miR)-142-3p, which suppresses autophagy. In this study, we found that wild-type C57BL/6 mice fed a vitamin D-deficient diet for 5 wk had increased miR-142-3p expression in ileal tissues compared with mice that were fed a matched control diet. Interestingly, there was no difference in expression of key autophagy markers ATG16L1 and LC3II in the ileum whole tissue. However, Paneth cells of vitamin D-deficient mice were morphologically abnormal and had an accumulation of the autophagy adaptor protein p62, which was not present in the total crypt epithelium. These findings suggest that Paneth cells exhibit early markers of autophagy dysregulation within the intestinal epithelium in response to vitamin D deficiency and enhanced miR-142-3p expression. Finally, we demonstrated that treatment-naïve IBD patients with low levels of vitamin D have an increase in miR-142-3p expression in colonic tissues procured from "involved" areas of the disease. Taken together, our findings demonstrate that insufficient vitamin D levels alter expression of autophagy-regulating miR-142-3p in intestinal tissues of mice and patients with IBD, providing insight into the mechanisms by which vitamin D deficiency modulates IBD pathogenesis.NEW & NOTEWORTHY Vitamin D deficiency has a role in IBD pathogenesis, and although the mechanisms surrounding its role remain unclear, it has been suggested that autophagy dysregulation is involved. Here, we show increased ileal expression of autophagy-suppressing miR-142-3p in mice that were fed a vitamin D-deficient diet and in "involved" colonic biopsies from pediatric IBD patients with low vitamin D. miR-142-3p serves as a potential mechanism mediating vitamin D deficiency and reduced autophagy.

Colorectal Dysplasia and Cancer in Pediatric-Onset Ulcerative Colitis Associated With Primary Sclerosing Cholangitis.

Inflammatory bowel disease (IBD), especially when associated with primary sclerosing cholangitis (PSC), is a risk factor for developing colorectal cancer (CRC).1-3 We aimed to determine the incidence of CRC in a large cohort of pediatric-onset PSC-ulcerative colitis (UC) patients.

Prospective Evaluation of Endoscopic and Histologic Indices in Pediatric Ulcerative Colitis Using Centralized Review.

INTRODUCTION: We aimed to evaluate the reliability and validity of the Ulcerative Colitis (UC) Endoscopic Index of Severity (UCEIS) and Mayo Endoscopy Score (MES) and to validate the Robarts Histopathology Index (RHI) and Nancy Index (NI) in pediatric UC. We examined rectosigmoid and pancolonic versions of each instrument. METHODS: Single-center cross-sectional study of 60 prospectively enrolled participants. Through central endoscopy review, 4 pediatric gastroenterologists assigned rectosigmoid and pancolonic (mean of 5 colonic segments) UCEIS and MES scores. Two blinded pathologists assigned rectosigmoid and pancolonic RHI and NI scores. We assessed reliability with intraclass correlation coefficients and weighted kappa statistics and explored construct validity with correlations, boxplots, and receiver operator characteristic curves. RESULTS: The UCEIS and MES displayed almost perfect intra-rater and inter-rater reliability (intraclass correlation coefficient and weighted kappa ≥0.85), moderate-to-strong correlation with histologic/clinical activity and fecal calprotectin (FC), and very strong correlation with global endoscopic severity (r > 0.9). Rectosigmoid UCEIS and MES scores of 0 were highly specific (≥95%) for endoscopic and histologic remission throughout the colon. Pancolonic endoscopy scores correlated more strongly with histologic activity, clinical activity, and systemic inflammatory markers and better discriminated between degrees of active disease. RHI and NI showed moderate-to-strong correlation (r = 0.5-0.83) with endoscopic/clinical activity and FC. DISCUSSION: Our findings support the reliability and construct validity of the UCEIS and MES and the construct validity of the RHI and NI in pediatric UC. Normal rectosigmoid findings predicted pancolonic healing, but, given active disease, pancolonic endoscopic assessment more accurately captured global disease burden.

Gut microbiota in chronic inflammatory disorders: A focus on pediatric inflammatory bowel diseases and juvenile idiopathic arthritis.

The gut microbiota is integral to human health, including maintaining the delicate balance between tolerance and protection against potentially harmful pathogens. A growing body of evidence implicates the intestinal microbiome in immune-mediated inflammatory disorders; these data span the spectrum from genetic and environmental disease risk factors, to animal studies (particularly germ-free and gnotobiotic models) and human studies, including evidence of dysbiosis in diseased individuals compared to healthy populations. In this review, we summarize both animal and human data supporting a link between the gut microbiota and inflammatory bowel diseases (IBD) and systemic inflammatory arthritis, as models for chronic inflammatory disorders, while offering a pediatric focus (pediatric IBD and juvenile idiopathic arthritis). We discuss relevant mechanisms related to the crosstalk between the gut microbiota and the innate and adaptive immune system. We close with a brief discussion of emerging microbe-altering interventions, including fecal microbial transplantation and its immunologic effects.

Primary Sclerosing Cholangitis in Children With Inflammatory Bowel Diseases Is Associated With Milder Clinical Activity But More Frequent Subclinical Inflammation and Growth Impairment.

BACKGROUND & AIMS: Although inflammatory bowel diseases (IBD) associated with primary sclerosing cholangitis (PSC) have been well characterized in adults, there have been few pediatric studies, and these were small and produced conflicting results. We investigated features of PSC-IBD in children, compared with children with IBD without PSC. METHODS: We performed a retrospective study of 74 children with PSC-IBD, diagnosed from 2000 through 2018, who were each matched with 2 children with ulcerative colitis or IBD-unclassified (controls) based on sex, date of birth, and type of IBD. We compared IBD distribution and clinical activity (remission, medication use, hospitalization, or colectomy) and patient growth between groups. Data were extracted from each hospital contact and analyzed using mixed effects analyses or Cox proportional hazards regression, adjusting for time-dependent medication exposure. RESULTS: Higher proportions of children with PSC-IBD had backwash ileitis, pancolitis, and rectal sparing, and more severe right-sided disease, than controls (P < .05). Patients with PSC-IBD were more likely to be treated with only 5-ASA, compared with controls (odds ratio [OR], 3.04; 95% CI, 1.44-6.41) and to have IBD in clinical remission (OR, 2.94; 95% CI, 1.78-4.87). Risk of colectomy or treatment with a biologic agent was lower in patients with PSC-IBD than controls (hazard ratio, 0.24; 95% CI, 0.12-0.52). However, determination of IBD severity based on symptoms underestimated severity based on endoscopic activity in patients with PSC-IBD. Among patients with IBD in clinical remission, those with PSC were less likely to have endoscopic remission (OR, 0.44; 95% CI, 0.20-0.96). Patients with PSC-IBD were shorter and had lower weight over time, compared with controls. CONCLUSIONS: In a retrospective study, we found that features of IBD differed between children with vs without PSC, similar to adults. Despite the mild clinical activity of IBD in patients with PSC, lack of symptoms does not always indicate lack of mucosal inflammation. Children with PSC-IBD have greater growth impairments compared with children with ulcerative colitis or IBD-unclassified.

Pediatric Wilson Disease Presenting as Acute Liver Failure: An Individual Patient Data Meta-analysis.

OBJECTIVES: Wilson disease (WD) presenting as acute liver failure (ALF) is rare and typically fatal without liver transplantation (LT). Its rarity has hindered comprehensive studies. We undertook an individual patient data meta-analysis to characterize a cohort of pediatric patients presenting with ALF whose final diagnosis was WD to examine outcomes and identify predictors of poor outcomes. METHODS: Database searches were conducted in PubMed, ScienceDirect, and Google Scholar, restricted to English-language articles published between January 1984 and May 2018. Articles were excluded if pediatric (<18 years old) data were not extractable or if LT was not readily available at reporting institutions. Extracted data included clinical and biochemical characteristics, genotype, treatment, and outcome. RESULTS: Data were available on 249 subjects from 52 articles, plus 7 additional subjects identified from our institution's WD database (N = 256). Females represented 69% (n = 170/245). Median age at presentation was 13.4 years (n = 204, range 4.0-17.9). Of the total 256 subjects, 87% underwent LT, 11% achieved spontaneous recovery and 2% died before LT. International normalized ratio >2.0 at presentation was a predictor of LT/death (odds ratio 7.6, 95% confidence interval 1.5-28), with a trend observed for hepatic encephalopathy (HE) (odds ratio 4.18, 95% confidence interval 0.99-18). Arithmetic diagnostic scores proved inferior in the pediatric age-bracket compared to adults. CONCLUSIONS: This large international pediatric cohort has permitted an individual patient data analysis of WD presenting as ALF. Notably, 11% of subjects achieved spontaneous survival; the rest required LT. Coagulopathy (international normalized ratio >2:0) and HE at presentation heralded poor outcomes. Further prospective studies may identify additional early predictors of outcomes.

Vedolizumab Therapy in Children With Primary Sclerosing Cholangitis: Data From the Pediatric Primary Sclerosing Cholangitis Consortium.

OBJECTIVES: Most patients with primary sclerosing cholangitis (PSC) also have inflammatory bowel disease (IBD). The liver and colon express MAdCAM-1, a target of lymphocyte homing integrins. Vedolizumab (VDZ) is an α4ß7 integrin antibody used to treat IBD. We investigated liver outcomes in children with PSC-IBD treated with VDZ. METHODS: Patients were identified within the Pediatric PSC Consortium, a multicenter research registry. Retrospective demographic, phenotypic, biochemical, radiological, histopathologic and IBD data for up to 1 year of VDZ therapy were collected. Liver biochemical and IBD responses were defined as: a 75% or greater reduction in initial γ-glutamyltransferase (GGT), or a GGT that fell to <50 IU/L and improved Mayo endoscopy grade or IBD activity scores after 9 to 12 months. RESULTS: Thirty-seven patients were identified from 19 centers. VDZ was initiated at median age of 16 years [IQR 15-18], 69% were male, 65% had large duct involvement, 19% had (Metavir F3/F4) fibrosis and 59% had ulcerative colitis. Of 32 patients with abnormal GGT at baseline, 22% had a liver biochemical response after 9 to 12 months. For IBD, 32% achieved remission, 30% had a clinical response, and 38% had no response. Final GGT after 9 to 12 months was 51 [IQR 28-71] in IBD patients in remission versus 127 [IQR 63-226] in those with active IBD, (P = 0.066). CONCLUSIONS: Liver biochemistry worsened over time in IBD unresponsive to VDZ but remained unchanged in IBD patients in remission. VDZ did not improve liver biochemistry in pediatric PSC-IBD. Progressive liver disease may be more common in patients with medically refractory IBD.

Assessing the Validity of Adult-derived Prognostic Models for Primary Sclerosing Cholangitis Outcomes in Children.

BACKGROUND: Natural history models for primary sclerosing cholangitis (PSC) are derived from adult patient data, but have never been validated in children. It is unclear how accurate such models are for children with PSC. METHODS: We utilized the pediatric PSC consortium database to assess the Revised Mayo Clinic, Amsterdam-Oxford, and Boberg models. We calculated the risk stratum and predicted survival for each patient within each model using patient data at PSC diagnosis, and compared it with observed survival. We evaluated model fit using the c-statistic. RESULTS: Model fit was good at 1 year (c-statistics 0.93, 0.87, 0.82) and fair at 10 years (0.78, 0.75, 0.69) in the Mayo, Boberg, and Amsterdam-Oxford models, respectively. The Mayo model correctly classified most children as low risk, whereas the Amsterdam-Oxford model incorrectly classified most as high risk. All of the models underestimated survival of patients classified as high risk. Albumin, bilirubin, AST, and platelets were most associated with outcomes. Autoimmune hepatitis was more prevalent in higher risk groups, and over-weighting of AST in these patients accounted for the observed versus predicted survival discrepancy. CONCLUSIONS: All 3 models offered good short-term discrimination of outcomes but only fair long-term discrimination. None of the models account for the high prevalence of features of autoimmune hepatitis overlap in children and the associated elevated aminotransferases. A pediatric-specific model is needed. AST, bilirubin, albumin, and platelets will be important predictors, but must be weighted to account for the unique features of PSC in children.

Clinical value of fecal calprotectin.

Inflammatory bowel disease (IBD) denotes a group of chronic incurable disorders characterized by relapsing-remitting inflammation of the gastrointestinal tract. IBD represents a growing global burden with a prevalence exceeding 0.3% in the Western world and an accelerating incidence in newly industrialized countries. The target for treating IBD has shifted in recent years from symptom control to mucosal healing (MH), which has been shown to be associated with favorable long-term outcomes. The gold standard for ascertaining MH is endoscopic assessment, but endoscopy is limited by its invasive nature, high cost, and finite availability. Surrogate biomarkers are therefore of great utility. Calprotectin, a cytosolic protein derived predominantly from neutrophils, is now widely used in this capacity. Calprotectin is found in various bodily fluids at concentrations proportional to the degree of inflammation, including in feces at levels roughly six times higher than in the blood. Fecal calprotectin (FCP) therefore reflects intestinal inflammation. Various assays, including point-of-care and home-based tests, are now available for measuring FCP. FCP is used for screening purposes, to aid in distinguishing inflammatory from non-inflammatory gastrointestinal conditions like irritable bowel syndrome (IBS), as well as in the monitoring of known IBD. The aims of this review are to provide an overview of the methods used to measure FCP and to review the evidence supporting the use of FCP in IBD, particularly as it pertains to screening, monitoring and predicting disease relapse.