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The gastrointestinal (GI) tract exhibits an enormous surface area that consists mostly of absorptive enterocytes. Enteroendocrine cells (EECs) are found scattered along the GI tract between absorptive enterocytes and other secretory cells, and comprise around 1% of the epithelial cell population. Interestingly, they develop from the same crypt stem cell as the other absorptive or secretory cells of the gut. EECs differentiate along the crypt villus axis and are renewed every 4-6 days, and hence possess a high plasticity. They constitute the largest endocrine system in the human body by secreting multiple peptide hormones to control, for example, postprandial digestion, insulin homeostasis, food intake, and gut motility. For this purpose, most EECs exhibit luminal sensors that detect the GI tract content. Thereafter, they may act either in a classical endocrine fashion, or by paracrine effects on nearby neural and immune cells. This creates a pivotal role for EECs to influence the GI immune system and the enteric nervous system. In this chapter, the anatomical characteristics, development, differentiation and maturation of EECs are described, and their important biological potential illustrated as part of the gut interacting sensory system.

Intolerance to lactose or fructose is frequently diagnosed in children with chronic abdominal pain (CAP). However, the causal relationship remains a matter of discussion. A cohort of 253 patients, aged 7&ndash, 12 years, presenting with unexplained CAP received standardized diagnostics. Additional diagnostic tests were performed based on their medical history and physical and laboratory investigations. Fructose and lactose hydrogen breath tests (H2BT) as well as empiric diagnostic elimination diets were performed in 135 patients reporting abdominal pain related to the consumption of lactose or fructose to evaluate carbohydrate intolerance as a potential cause of CAP. Carbohydrate malabsorption by H2BT was found in 55 (41%) out of 135 patients. An abnormal increase in H2BT was revealed in 30% (35/118) of patients after fructose consumption and in 18% (20/114) of patients after lactose administration. Forty-six percent (25/54) reported pain relief during a diagnostic elimination diet. In total, 17 patients had lactose malabsorption, 29 fructose malabsorption, and nine combined carbohydrate malabsorption. Carbohydrate intolerance as a cause of CAP was diagnosed at follow-up in only 18% (10/55) of patients with malabsorption after the elimination of the respective carbohydrate. Thus, carbohydrate malabsorption appears to be an incidental finding in children with functional abdominal pain disorders, rather than its cause. Therefore, testing of carbohydrate intolerance should only be considered in children with a strong clinical suspicion and with the goal to prevent long-term unnecessary dietary restrictions in children suffering from CAP.

Objective Comparing health-related quality of life (HRQOL) in children suffering from functional and organic gastrointestinal disorders and to identify predictors for HRQOL. Methods Children with functional (n = 70) and organic (n = 100) gastrointestinal disorders, aged 8-18 years and referred to a pediatric gastroenterologist, completed questionnaires assessing pain severity, coping, and HRQOL. Results The sample reported low HRQOL scores, even significantly lower compared with reference values of chronically ill children, derived from normative data of KINDL-R, a generic QOL questionnaire. HRQOL was not significantly associated with age, gender, duration of pain, and diagnosis (functional gastrointestinal disorder vs. organic gastrointestinal disorder). Pain severity and catastrophizing were significantly associated with HRQOL, with catastrophizing fully mediating the relationship between pain and HRQOL. Conclusion The emotional burden associated with chronic abdominal pain-regardless of its cause-is enormous. Interventions should target the children's coping strategies, as catastrophizing seems to be the causal link between pain and HRQOL.

The gastrointestinal (GI) tract exhibits an enormous surface area that consists mostly of absorptive enterocytes. Enteroendocrine cells (EECs) are found scattered along the GI tract between absorptive enterocytes and other secretory cells, and comprise around 1% of the epithelial cell population. Interestingly, they develop from the same crypt stem cell as the other absorptive or secretory cells of the gut. EECs differentiate along the crypt villus axis and are renewed every 4-6 days, and hence possess a high plasticity. They constitute the largest endocrine system in the human body by secreting multiple peptide hormones to control, for example, postprandial digestion, insulin homeostasis, food intake, and gut motility. For this purpose, most EECs exhibit luminal sensors that detect the GI tract content. Thereafter, they may act either in a classical endocrine fashion, or by paracrine effects on nearby neural and immune cells. This creates a pivotal role for EECs to influence the GI immune system and the enteric nervous system. In this chapter, the anatomical characteristics, development, differentiation and maturation of EECs are described, and their important biological potential illustrated as part of the gut interacting sensory system.

Familial hemophagocytic lymphohistiocytosis 5 (FHL5) is an autosomal recessive disease caused by mutations in STXBP2, coding for Munc18-2, which is required for SNARE-mediated membrane fusion. FHL5 causes hematologic and gastrointestinal symptoms characterized by chronic enteropathy that is reminiscent of microvillus inclusion disease (MVID). However, the molecular pathophysiology of FHL5-associated diarrhea is poorly understood. Five FHL5 patients, including four previously unreported patients, were studied. Morphology of duodenal sections was analyzed by electron and fluorescence microscopy. Small intestinal enterocytes and organoid-derived monolayers displayed the subcellular characteristics of MVID. For the analyses of Munc18-2-dependent SNARE-protein interactions, a Munc18-2 CaCo2-KO model cell line was generated by applying CRISPR/Cas9 technology. Munc18-2 is required for Slp4a/Stx3 interaction in fusion of cargo vesicles with the apical plasma membrane. Cargo trafficking was investigated in patient biopsies, patient-derived organoids, and the genome-edited model cell line. Loss of Munc18-2 selectively disrupts trafficking of certain apical brush-border proteins (NHE3 and GLUT5), while transport of DPPIV remained unaffected. Here, we describe the molecular mechanism how the loss of function of Munc18-2 leads to cargo-selective mislocalization of brush-border components and a subapical accumulation of cargo vesicles, as it is known from the loss of polarity phenotype in MVID.

Background Familial hemophagocytic lymphohistiocytosis (FHL) is a rare primary immune disorder defined by mutations in the syntaxin binding protein 2 (STXBP2) alias MUNC18-2. Despite defective immunity and a hyper-inflammatory state, clinical findings such as neurological, gastrointestinal, and bleeding disorders are present in a significant number of patients and suggest an impaired expression and function of STXBP2 in cells other than cytotoxic lymphocytes. Procedure We investigated four patients with FHL5 suffering from severe enteropathy and one of whom also had renal tubular dysfunction despite successful hematopoietic stem cell transplantation (HSCT). Gastrointestinal and renal biopsy specimens were analyzed by immunohistochemistry and electron microscopy. Results Histopathology revealed an intracytoplasmatic accumulation of PAS-positive granules and an enlarged intracytoplasmatic CD10-positive band along the apical pole of enterocytes. Electron microscopy revealed short microvilli and granules filled with electro lucent material. In addition, we described mildly dilated renal tubules and electron micrographs displayed a higher number of cytoplasmic inclusions, electrodense lysosomal and electrolucent endosomal vesicles. Conclusion Mutations in STXBP2 do not only affect cytotoxic T lymphocytes but also cause changes in the intestinal and renal epithelium resulting in severe, osmotic diarrhea and renal proximal tubular dysfunction. These defects persist after successful treatment of hemophagocytic lymphohistocytosis by HSCT. Clinical manifestations in FHL5 patients despite successful HSCT may therefore be related to defective membrane trafficking in the gut and kidney. Pediatr Blood Cancer 2013; 60: 1215–1222. © 2013 Wiley Periodicals, Inc.

The development of intramural duodenal haematoma (IDH) after small bowel biopsy is an unusual lesion and has only been reported in 18 children. Coagulopathy, thrombocytopenia and some special features of duodenal anatomy, e.g. relatively fixed position in the retroperitoneum and numerous submucosal blood vessels, have been suggested as a cause for IDH. The typical clinical presentation of IDH is severe abdominal pain and vomiting due to duodenal obstruction. In addition, it is often associated with pancreatitis and cholestasis. Diagnosis is confirmed using imaging techniques such as ultrasound, magnetic resonance imaging or computed tomography and upper intestinal series. Once diagnosis is confirmed and intestinal perforation excluded, conservative treatment with nasogastric tube and parenteral nutrition is sufficient. We present a case of massive IDH following endoscopic grasp forceps biopsy in a 5-year-old girl without bleeding disorder or other risk for IDH, which caused duodenal obstruction and mild pancreatitis and resolved within 2 weeks of conservative management. Since duodenal biopsies have become the common way to evaluate children or adults for suspected enteropathy, the occurrence of this complication is likely to increase. In conclusion, the review of the literature points out the risk for IDH especially in children with a history of bone marrow transplantation or leukaemia.

Congenital diarrheal disorders are rare, often fatal, diseases that are difficult to diagnose (often requiring biopsies) and that manifest in the first few weeks of life as chronic diarrhea and the malabsorption of nutrients. The etiology of congenital diarrheal disorders is diverse, but several are associated with defects in the predominant intestinal epithelial cell type, enterocytes. These particular congenital diarrheal disorders (CDDENT) include microvillus inclusion disease and congenital tufting enteropathy, and can feature in other diseases, such as hemophagocytic lymphohistiocytosis type 5 and trichohepatoenteric syndrome. Treatment options for most of these disorders are limited and an improved understanding of their molecular bases could help to drive the development of better therapies. Recently, mutations in genes that are involved in normal intestinal epithelial physiology have been associated with different CDDENT. Here, we review recent progress in understanding the cellular mechanisms of CDDENT. We highlight the potential of animal models and patient-specific stem-cell-based organoid cultures, as well as patient registries, to integrate basic and clinical research, with the aim of clarifying the pathogenesis of CDDENT and expediting the discovery of novel therapeutic strategies., Summary: Overview of the recent progress in our understanding of congenital diarrheal disorders, and the available models to study these diseases.

Background and study aims: The goal of this study was to analyze the bowel cleansing methods currently used for pediatric colonoscopy in terms of effectiveness, tolerance and safety. Patients and methods: Data from 768 colonoscopies reported by 28 centers were registered in an online database for further analysis. Binary logistic regression was used to determine how preparation methods affected the cleaning effect (Aronchick score) and the rate of adverse events (Aes) and complications. Results: The most frequently reported cleansing agents were sodium picosulphate (54.2 %) and polyethylene-glycol (41.3 %) in various combinations. The cleaning effect was good to excellent in 72.6 % of patients. AEs during the preparation period occurred in 21.5 % of patients. Complications during endoscopy were reported in 12.1 % and were mostly mild. The different agents had no influence on the cleaning effect. In contrast the risk of AEs during preparation was significantly increased when polyethylene-glycol was used (odds ratio (OR) 2.112, P = 0.002) but reduced with the use of sodium picosulphate (OR 0.380, P

Summary Dendritic cell (DC) development and function is critical in the initiation phase of any antigen-specific immune response against tumours. Impaired function of DC is one explanation as to how tumours escape immunosurveillance. In the presence of various soluble tumour-related factors DC precursors lose their ability to differentiate into mature DC and to activate T cells. Gangliosides are glycosphingolipids shed by tumours of neuroectodermal origin such as melanoma and neuroblastoma. In this investigation we address the question of whether gangliosides suppress the development and function of monocyte-derived DC in vitro. In the presence of gangliosides, the monocytic DC precursors showed increased adherence, cell spreading and a reduced number of dendrites. The expression of MHC class II molecules, co-stimulatory molecules and the GM-CSF receptor (CD116) on the ganglioside-treated DC was significantly reduced. Furthermore, the function of ganglioside-treated DC was impaired as observed in endocytosis, chemotactic and T cell proliferation assays. In contrast to monocytic DC precursors, mature DC were unaffected even when higher doses of gangliosides were added to the culture. With regard to their carbohydrate structure, five different gangliosides (GM2, GM3, GD2, GD3, GT1b), which are typically shed by melanoma and neuroblastoma, were tested for their ability to suppress DC development and function. Suppression was induced by GM2, but not by the other gangliosides. These data suggest that certain gangliosides impair DC precursors, implying a possible mechanism for tumour escape.

A new symptom-complex is described characterized by manifestations of autoimmune disease, infectious lymphadenopathy, double negative T cells, and impaired activation-induced cell death that developed in late adolescence. Similarities, but also significant differences, to autoimmune lymphoproliferative syndromes (ALPS, Canale-Smith syndrome) and autoimmune lymphoproliferative disease (ALD, Dianzani syndrome), were observed. The main clinical features were recurrent bacterial infections with subsequent lymphadenopathy due to autoimmune neutropenia. Laboratory results revealed a large proportion of alphabetaTCR positive, CD4 negative, CD8 negative, peripheral T cells, and a decreased apoptosis upon activation with phytohemagglutinin and interleukin 2, but normal Fas-mediated apoptosis. Genetic investigations excluded mutations in Fas gene death domain and in the 4 exons of Fas ligand gene. Despite unknown pathogenesis, this new syndrome might belong to the growing group of diseases with defects in apoptosis.

Identifying rare genetic forms of infantile cholestasis is challenging due to their similar clinical presentation and their diverse etiology. After exclusion of common non-genetic causes a huge list of rare differential diagnosis remains to be solved. More than 90 genes are associated with monogenic forms of infantile cholestasis, thus preventing routine genetic workup by Sanger sequencing. Here we demonstrate a next generation sequencing approach to discover the underlying cause in clinically well characterized patients in whom common causes of infantile cholestasis have been excluded. After validation of the analytical sensitivity massive parallel sequencing was performed for 93 genes in six prospectively studied patients. Six novel mutations (PKHD1: p.Thr777Met, p.Tyr2260Cys; ABCB11: p.Val1112Phe, c.611+1G > A, p.Gly628Trpfs*3 and NPC1: p.Glu391Lys) and two known pathogenic mutations were detected proving our multi gene panel for infantile cholestasis to be a sensitive and specific method overcoming the complexity of the phenotype-based, candidate gene approach. Three exemplary clinical cases of infants with cholestasis are presented and discussed in the context of their genetic and histopathological findings (autosomal recessive polycystic kidney disease, atypical PFIC and Niemann–Pick syndrome type C1). These case reports highlight the critical impact of integrating clinical, histopathological and genetic data during the process of multi gene panel testing to ultimately pinpoint rare genetic diagnoses.

The number of hospitalizations for head injuries in children is rising. The exact causes remain unclear. We analyzed data of children aged between 0 and 18 years who sustained a head injury between 2010 and 2011. The analysis focused on data related to demographics, trauma mechanism, clinical course, results of imaging scans, concomitant injuries, and outcome. A total of 794 inpatient cases of head injury were treated. The leading mechanism of injury was a fall (at home) primarily at the age of 1 to 4 years (46.5%), with the majority of the children sustaining a mild brain injury (764, 96.2%). Neurosurgery was performed in 21 (2.64%) cases; average hospital stay was 2.9 days (range: 0-68 days). This study is not able to confirm that children are increasingly being brought to the hospital by their parents because of new trauma mechanisms or parents’ uncertainty, nor can we confirm that the number of nonaccidental injuries is rising.

The gastrointestinal tract is the gateway for food in our body. Food ingestion and the ensuing digestive processes depend on the composition and amount of ingested nutrients. This complex process of nutrient digestion and absorption is effectively regulated by the enteroendocrine system. Enteroendocrine cells (EECs) reside scattered throughout the intestinal epithelium. They express nutrient receptors that face the lumen and secrete peptide hormones in response to food. Besides regulating digestion, gastrointestinal endocrine cells are involved in the regulation of appetite and satiety. The first part of this review describes the anatomical and biological characteristics of EECs and discusses the capability of their hormones to influence appetite, satiety, and body weight. In the second part, we then discuss the therapeutic potential of EECs in the treatment of obesity.

CD95-L, TNF-alpha and TRAIL are death-inducing ligands (DILs) which may signal apoptosis via crosslinking of their cognate receptors. The present study shows that treatment of cells with agonistic mAB alpha APO-1 (CD95), recombinant TRAIL or TNF-alpha leads to enhanced mRNA and protein expression of each DIL with concomitant death in target cells. Immunoprecipitation of CD95-L protein from supernatant as well as neutralizing antibodies suggest DIL proteins to be cooperatively acting mediators of these cytotoxic activity. Autoamplification of the death signal was blocked in cells with a defect in apoptosis signaling either due to a dysfunctional FADD molecule or to the failure to activate JNK/SAPKs. Phosphorylation and enhanced binding of cJun and ATF-2 to DIL promoters suggest JNK/SAPKs as activators of these transcription factors following death receptor triggering. In consequence, autocrine production of DILs allows the spread of death signals to sensitive target cells. Oncogene (2000) 19, 4255 - 4262

Enteroendocrine (EE) cells are necessary for the regulation of gastrointestinal function. The lack of intestinal enteroendocrine cells in enteroendocrine cell dysgenesis causes severe malabsorptive diarrhea. Autoimmune-polyendocrinopathy-candidiasis-ectodermal-dystrophy (APECED) is often accompanied by gastrointestinal (GI) symptoms.We hypothesized that an autoimmune attack against the cells of the GI-associated diffuse endocrine system may be a specific feature of GI dysfunction in APECED disorders.Biopsies were obtained during routine diagnostic endoscopy from 35 pediatric patients with gastrointestinal symptoms as well as from five healthy controls; biopsies were immunostained for chromogranin A and serotonin. Four patients were classified as APECED syndrome on molecular and clinical grounds.Immunohistological analysis of biopsies along the GI tract (stomach, duodenum, colon) immunostained with chromogranin A and serotonin revealed a widespread reduction or complete loss of EE cells in all four patients with APECED syndrome suffering from severe diarrhea, vomiting, malabsorption, or constipation. In contrast, EE cells were present in pediatric patients with similar gastrointestinal symptoms caused by inflammatory bowel disease, celiac disease, lymphocytic colitis, and autoimmune disorders without endocrinopathy or graft vs. host disease of the gut.The reduction of EE cells is a specific and important early event in the pathogenesis of APECED with GI dysfunction. We propose a diagnostic algorithm integrating clinics, genetics and immunohistology.

Human autoimmune lymphoproliferative syndrome (ALPS) is caused by defective CD95-mediated apoptosis of lymphocytes. In most patients, heterozygous mutations within the CD95 gene are found. Mutated proteins interfere with CD95-signaling in a dominant-negative way. However, the penetrance of clinical disease is variable. We describe 13 patients out of nine families with the clinical presentation of ALPS. Eight different mutations were detected. Sensitivity to CD95-induced cell-death, assembly of the CD95-death-inducing signaling complex (DISC), and activity of initiator caspases-8 and -10 were compared in EBV-transformed B-lymphoblastoid cells of these patients. All CD95-mutations led to a reduced DISC formation and diminished initiator caspase activity upon CD95-stimulation, whereas a marked heterogeneity in sensitivity to CD95-induced killing was found. Residual apoptosis sensitivity to almost normal levels could be achieved upon cross-linking by addition of protein A. Thus, no correlation between residual CD95 sensitivity and clinical phenotype or genotype of ALPS was found. This observation is only partially explained by the variable effects of the CD95-mutations themselves. It also points to a pronounced influence of additional factors, such as modifier pathways or exogenous effects apart from the CD95 pathway in the pathogenesis of ALPS.

The CD95 (APO-1/Fas) system plays an important role in lymphocyte homeostasis and contributes to anticancer drug-induced apoptosis in some tumor cells. Most childhood B-lineage ALL cells are constitutively resistant towards CD95-induced death. We report here that chemotherapeutic drugs, such as doxorubicin, cytarabine, methotrexate and 6-mercaptopurine, sensitize CD95-resistant pre-B-ALL cell lines for CD95- and lymphokine-activated killer (LAK)-induced cell death. Enhanced susceptibility in drug-treated cells was found to be associated with increased expression of CD95 mRNA and surface expression of CD95 protein, as well as loss of Bcl-xL protein and disturbance of mitochondrial function. Low level activation of caspases and cleavage of poly(ADP-ribose) polymerase following CD95 triggering was strongly increased in drug pre-treated cells. Furthermore, drug pre-treated cells could be rescued from CD95-mediated apoptosis by blocking the CD95-signaling pathway with a FADD-dominant negative expression construct. Our data suggest that chemotherapeutic drugs may sensitize pre-B ALL cells by at least two mechanisms: (1) by increasing CD95 expression; and (2) by lowering the threshold for apoptotic signals. These findings may explain the effectiveness of low-dose chemotherapy and indicate an active role for key molecules of apoptosis and the immune system during chemotherapy of leukemia.

BACKGROUND: Influence of genetic variants in the NOD2 gene may play a more important role in disease activity, behaviour and treatment of pediatric- than adult-onset Crohn's disease (CD). METHODS: 85 pediatric- and 117 adult-onset CD patients were tested for the three main NOD2 CD-associated variants (p.R702W, p.G908R and p.10007fs) and clinical data of at least two years of follow-up were compared regarding disease behaviour and activity, response to therapy and bone mineral density (BMD). RESULTS: Chronic active and moderate to severe course of CD is associated in patients with pediatric-onset (p=0.0001) and NOD2 variant alleles (p=0.0001). In pediatric-onset CD the average PCDAI-Score was significantly higher in patients carrying NOD2 variants (p=0.0008). In addition, underweight during course of the disease (p=0.012) was associated with NOD2 variants. Interestingly, osteoporosis was found more frequently in patients carrying NOD2 variant alleles (p=0.033), especially in pediatric-onset CD patients with homozygous NOD2 variants (p=0.037). Accordingly, low BMD in pediatric-onset CD is associated with a higher PCDAI (p=0.0092), chronic active disease (p=0.0148), underweight at diagnosis (p=0.0271) and during follow-up (p=0.0109). Furthermore, pediatric-onset CD patients with NOD2 variants are more frequently steroid-dependent or refractory (p=0.048) and need long-term immunosuppressive therapy (p=0.0213). CONCLUSIONS: These data suggests that the presence of any of the main NOD2 variants in CD is associated with osteoporosis and an age of onset dependent influence towards underweight, higher disease activity and a more intensive immunosuppressive therapy. This observation supports the idea for an early intensive treatment strategy in children and adolescent CD patients with NOD2 gene variants.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disorder typically presenting with chronic mucocutaneous candidiasis, hypoparathyroidism, and adrenal failure variably accompanied by other symptoms. APECED is caused by a mutation in the autoimmune regulator gene (AIRE). Today over 60 different mutations are known world-wide, most of them localized in exons 2, 8, and 10. We report here a German girl with rheumatoid factor positive arthritis, chronic mucocutaneous candidiasis, autoimmune hepatitis, chronic diarrhea, vitiligo, hypothyroidism, hypoparathyroidism, and adrenal failure who is homozygous for a novel mutation at the end of exon 3 of the AIRE gene (c.462G>A), within the conserved splice donor sequence. This mutation probably introduces a frameshift after amino acid 154 (p.Pro154fs) by skipping exon 4. In addition, we analyzed five other family members out of three generations for the AIRE gene mutation and for polymorphisms in the cytotoxic T lymphocyte antigen 4 (CTLA4) gene region and lymphoid protein tyrosine phosphatase (PTPN22) gene, which are associated with the occurrence of sporadic autoimmune Addison's disease, type 1 diabetes mellitus, and generalized vitiligo.

Background Functional abdominal pain (FAP) is not only a highly prevalent disease but also poses a considerable burden on children and their families. Untreated, FAP is highly persistent until adulthood, also leading to an increased risk of psychiatric disorders. Intervention studies underscore the efficacy of cognitive behavioral treatment approaches but are limited in terms of sample size, long-term follow-up data, controls and inclusion of psychosocial outcome data. Methods/Design In a multicenter randomized controlled trial, 112 children aged 7 to 12 years who fulfill the Rome III criteria for FAP will be allocated to an established cognitive behavioral training program for children with FAP (n = 56) or to an active control group (focusing on age-appropriate information delivery; n = 56). Randomization occurs centrally, blockwise and is stratified by center. This study is performed in five pediatric gastroenterology outpatient departments. Observer-blind assessments of outcome variables take place four times: pre-, post-, 3- and 12-months post-treatment. Primary outcome is the course of pain intensity and frequency. Secondary endpoints are health-related quality of life, pain-related coping and cognitions, as well as selfefficacy. Discussion This confirmatory randomized controlled clinical trial evaluates the efficacy of a cognitive behavioral intervention for children with FAP. By applying an active control group, time and attention processes can be controlled, and long-term follow-up data over the course of one year can be explored. Trial registration DRKS00005038 (date: 25 July 2013); NCT02030392 (date: 7 January 2014) Electronic supplementary material The online version of this article (doi:10.1186/1745-6215-15-357) contains supplementary material, which is available to authorized users.