Pediatric Metastatic Crohn's Disease of the Liver.

Metastatic Crohn's disease (MCD) is the manifestation of Crohn's disease outside of the gastrointestinal tract and most frequently involves mucocutaneous and pulmonary tissues. This is an uncommon phenomenon but is well characterized in the pediatric literature. In contrast, MCD affecting the liver has not previously been described in pediatrics. The pediatric gastroenterologist must be aware of the myriad of Crohn's disease-associated hepatopathies. We herein present the first reported case of pediatric MCD involving the liver and describe our targeted diagnostic evaluation and the patient's response to infliximab-dyyb.

Impact of COVID-19 on Pediatric Gastroenterology Fellow Training in North America.

BACKGROUND: The COVID-19 pandemic has drastically changed healthcare systems and training around the world. The Training Committee of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition sought to understand how COVID-19 has affected pediatric gastroenterology fellowship training. METHODS: A 21 question survey was distributed to all 77 pediatric gastroenterology fellowship program directors (PDs) in the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition program director database via email on April 7. Responses collected through April 19, 2020 were analyzed using descriptive statistics. RESULTS: Fifty-one of 77 (66%) PDs from the United States, Canada, and Mexico responded to the survey. Forty-six of 51 (90%) PDs reported that they were under a "stay-at-home" order for a median of 4 weeks at the time of the survey. Two of the 51 (4%) programs had fellows participating in outpatient telehealth before COVID-19 and 39 of 51 (76%) at the time of the survey. Fellows stopped participating in outpatient clinics in 22 of 51 (43%) programs and endoscopy in 26 of 51 (52%) programs. Changes to inpatient care included reduced fellow staffing, limiting who entered patient rooms, and rounding remotely. Fellows in 3 New York programs were deployed to adult medicine units. Didactics were moved to virtual conferences in 47 of 51 (94%) programs, and fellows used various online resources. Clinical research and, disproportionately, bench research were restricted. CONCLUSIONS: This report provides early information of the impact of COVID-19 on pediatric fellowship training. Rapid adoption of telehealth and reduced clinical and research experiences were important changes. Survey information may spur communication and innovation to help educators adapt.

Management of acute severe ulcerative colitis in children.

The incidence of pediatric-onset ulcerative colitis (UC) is rising. Children often present with a more severe disease phenotype as compared to adults with over a third requiring hospitalization for the management of acute severe ulcerative colitis (ASUC). Further, in pediatric patients presenting with inflammatory bowel disease (IBD) limited to the colon, a definitive diagnosis of UC vs. Crohn's disease is often unclear. Here, we review the unique aspects of pediatric ASUC including the epidemiology, diagnosis, medical, and surgical management of this disease.

Atypical Hemolytic Uremic Syndrome and Chronic Ulcerative Colitis Treated with Eculizumab.

BACKGROUND: Hemolytic-uremic syndrome (HUS) presents with hemolytic anemia, thrombocytopenia, and thrombotic microangiopathy of the kidney and usually results from Shiga-toxin induced activation of the alternative complement pathway. Gastroenteritis is a common feature of the Shiga-toxin producing Escherichia coli HUS, referred to as STEC-HUS. An inherited or acquired complement dysregulation may lead to HUS referred to as non-STEC or atypical (a)HUS. Although gastroenteritis is not a common presentation of aHUS, some patients develop ischemic colitis and may be misdiagnosed as acute appendicitis or acute ulcerative colitis (UC). CASE DIAGNOSIS ­TREATMENT: We present a patient with low circulating complement (C) 3 levels who developed aHUS in the course of chronic active UC. Resolution of renal and gastrointestinal manifestations in response to treatment with eculizumab, a humanized monoclonal antibody against terminal C5 protein suggests the role of alternative complement in the pathogenesis of both, aHUS and UC. CONCLUSION: This case illustrates that dysregulation of the alternative complement pathway may manifest in other organs besides the kidney and that the circulating C3 levels do not correlate with the disease activity or the clinical response to eculizumab.

ADAM10 regulates Notch function in intestinal stem cells of mice.

BACKGROUND & AIMS: A disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) is a cell surface sheddase that regulates physiologic processes, including Notch signaling. ADAM10 is expressed in all intestinal epithelial cell types, but the requirement for ADAM10 signaling in crypt homeostasis is not well defined. METHODS: We analyzed intestinal tissues from mice with constitutive (Vil-Cre;Adam10(f/f) mice) and conditional (Vil-CreER;Adam10(f/f) and Leucine-rich repeat-containing GPCR5 [Lgr5]-CreER;Adam10(f/f) mice) deletion of ADAM10. We performed cell lineage-tracing experiments in mice that expressed a gain-of-function allele of Notch in the intestine (Rosa26(NICD)), or mice with intestine-specific disruption of Notch (Rosa26(DN-MAML)), to examine the effects of ADAM10 deletion on cell fate specification and intestinal stem cell maintenance. RESULTS: Loss of ADAM10 from developing and adult intestine caused lethality associated with altered intestinal morphology, reduced progenitor cell proliferation, and increased secretory cell differentiation. ADAM10 deletion led to the replacement of intestinal cell progenitors with 2 distinct, post-mitotic, secretory cell lineages: intermediate-like (Paneth/goblet) and enteroendocrine cells. Based on analysis of Rosa26(NICD) and Rosa26(DN-MAML) mice, we determined that ADAM10 controls these cell fate decisions by regulating Notch signaling. Cell lineage-tracing experiments showed that ADAM10 is required for survival of Lgr5(+) crypt-based columnar cells. Our findings indicate that Notch-activated stem cells have a competitive advantage for occupation of the stem cell niche. CONCLUSIONS: ADAM10 acts in a cell autonomous manner within the intestinal crypt compartment to regulate Notch signaling. This process is required for progenitor cell lineage specification and crypt-based columnar cell maintenance.