Anthropometrics and fat mass, but not fat-free mass, are compromised in infants requiring parenteral nutrition after neonatal intestinal surgery.

BACKGROUND: Children with intestinal failure (IF) receiving long-term parenteral nutrition (PN) have altered body composition (BC), but data on BC changes from start of PN onwards are lacking. OBJECTIVES: We aimed to assess growth and BC in infants after neonatal intestinal surgery necessitating PN and at risk of IF, and to explore associations with clinical parameters. METHODS: A prospective cohort study in infants after intestinal surgery. IF was defined as PN dependency for >60 d. SD scores (SDS) for anthropometry were calculated until 6-mo corrected age. In a subgroup, fat mass (FM) and fat-free mass (FFM) were measured with air-displacement plethysmography at 2- and 6-mo corrected age. SDS for length-adjusted FM index and FFM index were calculated. Associations between cumulative amount of PN and BC parameters were analyzed with linear mixed-effect models. RESULTS: Ninety-five neonates were included (54% male, 35% born <32 wk) and 39 infants (41%) had IF. Studied infants had compromised anthropometric parameters during follow-up. At 6-mo corrected age, they remained smaller (median weight-for-age SDS -0.9 [IQR -1.5, 0.1], P < 0.001) than the normal population. In 57 infants, 93 BC measurements were performed. FM index SDS was lower than in healthy infants at 2- and 6-mo corrected age (-0.9 [-1.6, -0.3], P < 0.001 and -0.7 [-1.3, 0.1], P = 0.001, respectively), but FFM index SDS did not differ. A higher cumulative amount of PN predicted a higher FM index in female infants but lower FM index in male infants. CONCLUSIONS: In this cohort of infants receiving PN after intestinal surgery, compromised anthropometrics, decreased FM, and adequate FFM were observed during the first 6 mo. Male and female infants seemed to respond differently to PN when it comes to FM index. Continuing growth monitoring after the age of 6 mo is strongly recommended, and further research should explore the benefit of incorporating ongoing BC monitoring during follow-up.

Assessment of the Clinical Benefit of Imaging in Children With Unilateral Sensorineural Hearing Loss: A Systematic Review and Meta-analysis.

IMPORTANCE: Imaging used to determine the cause of unilateral sensorineural hearing loss (USNHL) in children is often justified by the high likelihood of detecting abnormalities, which implies that these abnormalities are associated with hearing loss and that imaging has a positive contribution to patient outcome or well-being by providing information on the prognosis, hereditary factors, or cause of hearing loss. OBJECTIVES: To evaluate the diagnostic yield of computed tomography (CT) and magnetic resonance imaging (MRI) in children with isolated unexplained USNHL and investigate the clinical relevance of these findings. EVIDENCE REVIEW: Cochrane Library, Embase, PubMed, and Web of Science databases were searched for articles published from 1978 to 2017 on studies of children with USNHL who underwent CT and/or MRI of the temporal bone. Two authors (F.G.R. and E.N.B.P.) independently extracted information on population characteristics, imaging modality, and the prevalence of abnormalities and assessed the studies for risk of bias. Eligibility criteria included studies with 20 or more patients with USNHL who had CT and/or MRI scans, a population younger than 18 years, and those published in English. MAIN OUTCOMES AND MEASURES: The pooled prevalence with 95% CI of inner ear abnormalities grouped according to finding and imaging modality. FINDINGS: Of 1562 studies, 18 were included with a total of 1504 participants included in the analysis. Fifteen studies were consecutive case studies and 3 were retrospective cohort studies. The pooled diagnostic yield for pathophysiologic relevant findings in patients with unexplained USNHL was 37% for CT (95% CI, 25%-48%) and 35% for MRI (95% CI, 22%-49%). Cochleovestibular abnormalities were found with a pooled frequency of 19% for CT (95% CI, 14%-25%) and 16% for MRI (95% CI, 7%-25%). Cochlear nerve deficiency and associated cochlear aperture stenosis had a pooled frequency of 16% for MRI (95% CI, 3%-29%) and 44% for CT (95% CI, 36%-53%), respectively. Enlarged vestibular aqueduct (EVA) was detected with a pooled frequency of 7% for CT and 12% for MRI in children with USNHL. CONCLUSIONS AND RELEVANCE: Imaging provided insight into the cause of hearing loss in a pooled frequency of about 35% to 37% in children with isolated unexplained USNHL. However, none of these findings had therapeutic consequences, and imaging provided information on prognosis and hereditary factors only in a small proportion of children, namely those with EVA. Thus, there is currently no convincing evidence supporting a strong recommendation for imaging in children who present with USNHL. The advantages of imaging should be carefully balanced against the drawbacks during shared decision making.

Determinants of Advanced Bone Age in Childhood Obesity
.

BACKGROUND: Childhood obesity is associated with advanced bone age (BA). Previous studies suggest that androgens, oestrogens, sex hormone-binding globulin, and insulin are responsible for this phenomenon, but results are contradictory and might be biased by confounders. We aim to elucidate this matter by applying a multivariate approach. METHOD: We performed a correlation analysis of BA standard deviation score (SDS) with age- and sex-specific SDS for androgens, oestrogens, and with indicators of insulin secretion derived from oral glucose tolerance testing, in a group of obese children. A multivariate analysis was performed to investigate which parameters were independently predictive of BA SDS. RESULTS: In this cohort (n = 101; mean age 10.9 years; mean BA 11.8 years; mean BMI SDS 3.3), BMI SDS was significantly correlated to BA SDS (r = 0.55, p < 0.001). In a regression analysis in the total cohort (B = 0.27, p < 0.001) as well as in females (B = 0.34, p = 0.042), males (B = 0.31, p = 0.006), and pubertal children (B = 0.32, p = 0.046), dehydroepiandrosterone sulphate (DHEAS) showed a positive, independent association with BA SDS. No association with indicators of insulin secretion was found. CONCLUSION: BMI SDS is highly correlated to BA SDS in obese children. Increased DHEAS has a central role in advanced BA in obese children.
.

Feeding strategies in pediatric cancer patients with gastrointestinal mucositis: a multicenter prospective observational study and international survey.

INTRODUCTION: Currently, there is no adequate prevention or treatment for both oral and gastrointestinal mucositis induced by chemotherapy and/or radiotherapy. Supportive care of symptoms plays a primary role during mucositis in the pediatric clinical setting. We aimed to get insight in the currently used feeding strategies in clinical practice in pediatric cancer patients with chemotherapy-induced mucositis. METHODS: A prospective observational study was performed to identify feeding strategies after chemotherapy courses causing mucositis in almost all patients at the University Medical Center Groningen (UMCG), the Academic Medical Center Amsterdam (AMC), and the Princess Maxima Center Utrecht (PMC). Consecutive patients, aged 0-18 years, either diagnosed with B cell non-Hodgkin lymphoma (B-NHL) or scheduled for autologous stem cell transplantation (SCT) between April 2015 and September 2016 were included in this study. In addition to the observational study in the Netherlands, an international online questionnaire was conducted for pediatric oncology centers. RESULTS: A total of 13 patients were included, after 21 chemotherapy courses. No nutritional support was administered after 23.8% courses, tube feeding after 19.0% of the courses, TPN in 19.0% of courses, and 38.1% received a combination of tube feeding and TPN. The international survey revealed that 63.2% of the centers administered tube feeding as first choice, 31.6% administered only TPN as first choice, and one center administered a combination as first choice. CONCLUSIONS: There is a variability in feeding strategies in the clinical practice both in the Netherlands as well as worldwide. This study is a basis for future studies in this important clinical field to develop clinical trials comparing tube feeding and TPN both in adult and pediatric patients.

Effect of Oral Insulin on the Severity and Recovery of Methotrexate-Induced Gastrointestinal Mucositis in the Rat.

OBJECTIVES: Gastrointestinal (GI) mucositis is an adverse-effect of chemo- and radiotherapy. Oral insulin has been suggested as possible intestinal growth factor and possible intervention for GI mucositis. We aimed to determine the effect of oral insulin on the severity and recovery of mucositis in a methotrexate (MTX)-induced GI mucositis rat model. METHODS: Male Wistar rats (n = 24) received a single injection of 60 mg/kg MTX intravenously at day 0. From day -3 oral insulin was added to the drinking water. Group MTX received normal drinking water, group MTX+INS0.5 received 0.5 U/mL insulin, and group MTX+INS1 received 1 U/mL insulin in drinking water. The severity of mucositis was determined by intake, bodyweight, illness, and plasma citrulline. In the recovery phase, the function of the gut was tested with an oral glucose tolerance test, and villus and crypt length of the small intestine were measured. RESULTS: MTX-induced mucositis in all 3 groups and oral insulin did not cause a change in the severity of mucositis, with comparable bodyweight, food intake, and water intake. Oral insulin did not alter the enterocyte mass, determined with plasma citrulline. The glucose level after bolus was higher in the MTX group than the MTX+INS1 group (P < 0.05). Histology was not significant different between all groups. CONCLUSIONS: Oral insulin does not alter the severity or the acceleration of recovery of mucositis. Therefore, we conclude that it is not useful to further study oral insulin as possible intervention to prevent or treat chemotherapy-induced GI mucositis.

Tumor Necrosis Factor-Alpha Inhibitor Etanercept Does Not Alter Methotrexate-Induced Gastrointestinal Mucositis in Rats.

OBJECTIVES: Gastrointestinal (GI) mucositis is a severe adverse effect of chemotherapy and radiotherapy. Proinflammatory cytokines are thought to play an important role in the pathophysiology of GI mucositis. We aimed to determine the effect of the tumor necrosis factor-alpha (TNF-α) inhibitor etanercept on the severity of mucositis in a previously established methotrexate (MTX)-induced GI mucositis rat model. METHODS: Male Wistar rats received 60 mg/kg MTX on day 0 intravenously. Rats were treated daily with either etanercept (TNF-α inhibitor) 5 mg/kg or NaCl 0.9% subcutaneously from day -3 till day 3. Control rats received NaCl 0.9% intravenously and etanercept subcutaneously. The severity of mucositis was determined by intake, bodyweight, plasma citrulline, and by a function test (absorption of an oral glucose bolus). On day 4 and day 10 rats were terminated. Villus length, crypt length, intestinal myeloperoxidase, and plasma etanercept levels were determined. RESULTS: The administration of MTX induced mucositis in all rats. Etanercept did not cause a change in the degree of mucositis. Bodyweight, intake, and glucose levels were not altered by etanercept; villus length was comparable; and there was no difference in myeloperoxidase and citrulline level. Etanercept levels in plasma were significantly increased in the etanercept rats (P < 0.05). CONCLUSIONS: TNF-α inhibitor etanercept did not alter the severity of mucositis in the rat, suggesting that targeting only the inflammatory pathway of TNF-α is not effective for decreasing the severity of GI mucositis induced by high-dose MTX. Etanercept alone is not useful for the treatment of MTX-induced GI mucositis.

Effect of minimal enteral feeding on recovery in a methotrexate-induced gastrointestinal mucositis rat model.

PURPOSE: Patients suffering from gastrointestinal mucositis often receive parenteral nutrition as nutritional support. However, the absence of enteral nutrition might not be beneficial for the intestine. We aimed to determine the feasibility of minimal enteral feeding (MEF) administration in a methotrexate (MTX)-induced mucositis rat model and thereby determine the effect of MEF on recovery. METHODS: Male Wistar rats were attached to swivel systems from day 1 to 5 after 45 mg/kg MTX IV injection. The MTX group continued ad libitum feeding, and the MTX + MEF group continued ad libitum feeding and received from day 1 to 5 continuously MEF. MEF consisted of 20% of their normal caloric intake. We measured body weight, intake, and plasma citrulline. At day 10, the rats were terminated and villus and crypt length were measured. RESULTS: The administration of MEF caused no increased severity of mucositis phenotype, with comparable caloric intake, body weight, and plasma citrulline during mucositis. The recovery of plasma citrulline levels was not different between both groups. At day 7 and 8, the MTX + MEF group gained significantly more weight (p < 0.05 and p < 0.01, respectively), and at day 8 and 9 the total caloric intake was significantly increased (p < 0.01 and p < 0.05, respectively) compared to the MTX group. At day 10, the rats from the MTX + MEF group showed a significant increase in jejunal villus length compared to the MTX group (p < 0.05). CONCLUSIONS: This is the first study in which the feasibility of MEF administration during chemotherapy-induced mucositis was determined. This study indicates that MEF administration is feasible during mucositis and suggests that MEF accelerates recovery after MTX-induced mucositis.

Risk analysis, diagnosis and management of gastrointestinal mucositis in pediatric cancer patients.

Mucositis is a complex inflammatory reaction of the mucous membranes of the alimentary tract upon chemotherapy and radiotherapy treatment in oncology patients. Mucositis can be subdivided in oral and gastrointestinal mucositis (GI mucositis). The damage to the gastrointestinal tract compromises the intestinal function and thereby the nutritional status and the quality of life, and eventually affects survival. The literature on GI mucositis focuses mainly on adults. This review focuses on data available on GI mucositis in pediatric cancer patients. An evaluation of the clinical presentation and consequences of GI mucositis in children is outlined. The review summarizes key issues for clinicians with respect to risk analysis for developing mucositis and the diagnosis of this condition in children. Information on these issues is obtained from clinical trials in children and adults, and from animal models. Diagnostic tools and assessment of severity of GI mucositis in children is elaborated on. Furthermore, the clinical management of the symptoms and consequences of GI mucositis in children, with specific focus on nutritional support, are discussed.

Substantial decreases in the number and diversity of microbiota during chemotherapy-induced gastrointestinal mucositis in a rat model.

PURPOSE: Earlier, we showed in acute myeloid leukemia (AML) patients that the microbiota changes dramatically during anticancer treatment, coinciding with gastrointestinal mucositis: The commensal anaerobic populations reduce in favor of potential pathogens. Therefore, interventions targeting the microbiota during mucositis might be interesting but can better be tested in animals than in vulnerable mucositis patients. Here, we aimed to study the potential microbial changes during methotrexate (MTX)-induced gastrointestinal mucositis in a well-established rat model and to study whether this model can be used for future microbial intervention studies. METHODS: After injection with MTX or saline (day 0), rats were sacrificed between days 2 and 11. Plasma citrulline level, jejunal histology, and the number and diversity of intestinal bacteria in feces (using fluorescence in situ hybridization (FISH)) were determined. RESULTS: Mucositis was most severe on day 4 when food intake, plasma citrulline, and villus length were the lowest, compared with controls (P < 0.0125). At the same time, MTX-treated rats showed an overall decrease (705-fold) in most bacteria (using a universal probe), compared with controls (P < 0.125). Reduced bacterial presence was related with the presence of diarrhea and a reduced villus length (rho = 0.38, P < 0.05). At day 4, there was an absolute and relative decrease of anaerobes (13-fold and -58 %, respectively) and streptococci (296-fold and -1 %, respectively) but a relative increase of Bacteroides (+49 %), compared with controls (P < 0.125). CONCLUSIONS: In the mucositis rat model, we found substantial decreases in the number and diversity of microbiota, resembling earlier findings in humans. The model therefore seems well suited to study the effects of different microbial interventions on mucositis, prior to performing human studies.

Myosin Vb and Rab11a regulate phosphorylation of ezrin in enterocytes.

Microvilli at the apical surface of enterocytes allow the efficient absorption of nutrients in the intestine. Ezrin activation by its phosphorylation at T567 is important for microvilli development, but how such ezrin phosphorylation is controlled is not well understood. We demonstrate that a subset of kinases that phosphorylate ezrin closely co-distributes with apical recycling endosome marker Rab11a in the subapical domain. Expression of dominant-negative Rab11a mutant or depletion of the Rab11a-binding motor protein myosin Vb prevents the subapical enrichment of Rab11a and these kinases and inhibits ezrin phosphorylation and microvilli development, without affecting the polarized distribution of ezrin itself. We observe a similar loss of the subapical enrichment of Rab11a and the kinases and reduced phosphorylation of ezrin in microvillus inclusion disease, which is associated with MYO5B mutations, intestinal microvilli atrophy and malabsorption. Thus, part of the machinery for ezrin activation depends on recycling endosomes controlled by myosin Vb and Rab11a which, we propose, might act as subapical signaling platforms that enterocytes use to regulate development of microvilli and maintain human intestinal function.

An overview and online registry of microvillus inclusion disease patients and their MYO5B mutations.

Microvillus inclusion disease (MVID) is one of the most severe congenital intestinal disorders and is characterized by neonatal secretory diarrhea and the inability to absorb nutrients from the intestinal lumen. MVID is associated with patient-, family-, and ancestry-unique mutations in the MYO5B gene, encoding the actin-based motor protein myosin Vb. Here, we review the MYO5B gene and all currently known MYO5B mutations and for the first time methodologically categorize these with regard to functional protein domains and recurrence in MYO7A associated with Usher syndrome and other myosins. We also review animal models for MVID and the latest data on functional studies related to the myosin Vb protein. To congregate existing and future information on MVID geno-/phenotypes and facilitate its quick and easy sharing among clinicians and researchers, we have constructed an online MOLGENIS-based international patient registry (www.MVID-central.org). This easily accessible database currently contains detailed information of 137 MVID patients together with reported clinical/phenotypic details and 41 unique MYO5B mutations, of which several unpublished. The future expansion and prospective nature of this registry is expected to improve disease diagnosis, prognosis, and genetic counseling.

Laxative treatment with polyethylene glycol decreases microbial primary bile salt dehydroxylation and lipid metabolism in the intestine of rats.

Polyethylene glycol (PEG) is a frequently used osmotic laxative that accelerates gastrointestinal transit. It has remained unclear, however, whether PEG affects intestinal functions. We aimed to determine the effect of PEG treatment on intestinal sterol metabolism. Rats were treated with PEG in drinking water (7%) for 2 wk or left untreated (controls). We studied the enterohepatic circulation of the major bile salt (BS) cholate with a plasma stable isotope dilution technique and determined BS profiles and concentrations in bile, intestinal lumen contents, and feces. We determined the fecal excretion of cholesterol plus its intestinally formed metabolites. Finally, we determined the cytolytic activity of fecal water (a surrogate marker of colorectal cancer risk) and the amount and composition of fecal microbiota. Compared with control rats, PEG treatment increased the pool size (+51%; P < 0.01) and decreased the fractional turnover of cholate (-32%; P < 0.01). PEG did not affect the cholate synthesis rate, corresponding with an unaffected fecal primary BS excretion. PEG reduced fecal excretion of secondary BS and of cholesterol metabolites (each P < 0.01). PEG decreased the cytolytic activity of fecal water [54 (46-62) vs. 87 (85-92)% erythrocyte potassium release in PEG-treated and control rats, respectively; P < 0.01]. PEG treatment increased the contribution of Verrucomicrobia (P < 0.01) and decreased that of Firmicutes (P < 0.01) in fecal flora. We concluded that PEG treatment changes the intestinal bacterial composition, decreases the bacterial dehydroxylation of primary BS and the metabolism of cholesterol, and increases the pool size of the primary BS cholate in rats.

Continuous enteral administration can overcome the limited capacity to absorb glucose in rats with methotrexate-induced gastrointestinal mucositis.

BACKGROUND: Patients with chemotherapy-induced gastrointestinal mucositis often suffer from weight loss. It is not well known how to enterally feed mucositis patients, potentially experiencing malabsorption. Recently, we showed in a rat model of methotrexate (MTX)-induced mucositis that intestinal absorption of glucose in trace amounts is still intact. We now determined the quantitative capacity to absorb glucose in rats with mucositis, relative to controls. METHODS: We administered a physiologically relevant amount of [1-(13)C]glucose-enriched glucose (meal size) as a bolus by oral gavage (2 g/kg once) or continuously by intraduodenal infusion (±1.9 g/(kg·h) for 5 h) to rats with MTX-induced mucositis and controls. Blood [1-(13)C]glucose concentrations were determined during the experimental period. To calculate the quantitative absorptive capacity, Steele's one-compartment model, including simultaneous intravenous infusion of [6,6-(2)H(2)]glucose, was used. After the experiment, jejunal histology and plasma citrulline concentrations were assessed. RESULTS: MTX-induced mucositis was confirmed by a reduction in villus length and plasma citrulline (both -57%, relative to controls, P < 0.01). When glucose was administered as a bolus, MTX-treated rats only absorbed 15% of administered glucose, compared with 85% in controls (medians, P < 0.01). Upon continuous intraduodenal glucose infusion, the median absorptive capacity for glucose in MTX-treated rats did not differ from controls (80 versus 93% of administered glucose respectively, P = 0.06). However, glucose absorption differed substantially between individual MTX-treated rats (range, 21-95%), which correlated poorly with villus length (rho = 0.54, P = 0.030) and plasma citrulline (rho = 0.56, P = 0.024). CONCLUSION: Continuous enteral administration can almost completely overcome the reduced absorptive capacity for glucose in rats with mucositis.

Reduced absorption of long-chain fatty acids during methotrexate-induced gastrointestinal mucositis in the rat.

BACKGROUND & AIMS: Patients with chemotherapy-induced gastrointestinal mucositis suffer from weight loss and possibly malabsorption. Since long-chain fatty acids serve important functions in the body, we aimed to determine the intestinal capacity of fat absorption in rats with and without methotrexate-induced mucositis. METHODS: Four days after intravenous injection with methotrexate (60 mg/kg) or saline, rats received saturated ([U-(13)C]palmitic acid) and unsaturated ([U-(13)C]linoleic acid) fatty acids dissolved in oil, either as a single bolus by oral gavage or by continuous intraduodenal infusion. We determined plasma and liver label concentrations at specific time points. RESULTS: We confirmed methotrexate-induced mucositis by villus atrophy using microscopy. Methotrexate treatment severely reduced the appearance of [U-(13)C]palmitic- and [U-(13)C]linoleic acid in plasma and liver, compared to controls, either when administered as a bolus or continuously (all at least -63%, P < 0.05). Liver [U-(13)C]palmitic acid appearance was higher than [U-(13)C]linoleic acid appearance, either when administered as a bolus (2.8-fold, P < 0.01) or continuously (5.7-fold, P < 0.01). CONCLUSIONS: The intestinal capacity to absorb long-chain fatty acids is severely reduced in rats with methotrexate-induced mucositis. Continuous administration does not overcome this impairment. The liver takes up and/or retains mainly saturated fatty acids during mucositis.

Continuous enteral administration can enable normal amino acid absorption in rats with methotrexate-induced gastrointestinal mucositis.

It is unknown what feeding strategy to use during chemotherapy-induced gastrointestinal mucositis, which causes weight loss and possibly malabsorption. To study the absorptive capacity of amino acids during mucositis, we determined the plasma availability of enterally administered amino acids (AA), their utilization for protein synthesis, and the preferential side of the intestine for AA uptake in rats with and without methotrexate (MTX)-induced mucositis. Four days after injection with MTX (60 mg/kg) or saline (controls), rats received a primed, continuous dual-isotope infusion (intraduodenal and intravenous) of labeled L-leucine, L-lysine, L-phenylalanine, L-threonine, and L-methionine. We collected blood samples, assessed jejunal histology, and determined labeled AA incorporation in proximal and distal small intestinal mucosa, plasma albumin, liver, and thigh muscle. MTX-induced mucositis was confirmed by histology. The median systemic availability of all AA except for leucine was similar in MTX-treated rats and in controls. However, the individual availability of all AA differed substantially within the group of MTX-treated rats, ranging from severely reduced (<10% of intake) to not different from controls (>40% of intake in 5 of 9 rats). More AA originating from basolateral uptake than those originating from apical uptake were used for intestinal protein synthesis in MTX-treated rats (≥420% more, P < 0.05). We conclude that continuous enteral administration can enable normal AA absorption in rats with MTX-induced mucositis. The intestine prefers basolateral AA uptake to meet its need for AA for protein synthesis during mucositis.

MYO5B mutations in patients with microvillus inclusion disease presenting with transient renal Fanconi syndrome.

BACKGROUND AND OBJECTIVE: : Microvillus inclusion disease (MVID) is a rare congenital enteropathy associated with brush border atrophy and reduced expression of enzymes at the enterocytes' apical surface. MVID is associated with mutations in the MYO5B gene, which is expressed in all epithelial tissues. Whether organs other than the intestine are affected in MVID is unclear. We report 2 patients with MVID that developed renal Fanconi syndrome while receiving total parenteral nutrition. Renal Fanconi syndrome has been correlated to apical plasma membrane defects in kidney proximal tubular epithelial cells. The aim of the present study was to determine whether MYO5B mutations in these patients correlate with similar apical plasma membrane defects in renal tubular epithelial cells as observed in the intestine. METHODS: : Biopsies from kidney, duodenum, ileum, jejunum, and colon of 2 patients with MVID carrying MYO5B mutations and of age-matched controls were fixed in paraffin and analyzed with immunohistochemistry and transmission electron microscopy. RESULTS: : Structural defects of the brush border and apical recycling endosome organization are observed in enterocytes of all of the segments of the small intestine and colon. MYO5B mutations in patients with MVID with renal Fanconi syndrome do not correlate with aberrant apical plasma membrane morphology or altered apical recycling endosome organization in renal tubular epithelial cells. CONCLUSIONS: : MYO5B mutations have divergent effects on the apical membrane system in kidney and intestinal epithelial cells. Epithelial defects presented in MVID are therefore likely triggered by intestine-specific factors, the identification of which may provide new targets and open avenues for the development of alternative therapeutic strategies to combat this devastating disease.

[Autoimmune enteropathy in children]. / Auto-immune enteropathie bij kinderen.

Autoimmune enteropathy is a rare syndrome which, in children in its most severe form, causes severe life-threatening diarrhoea and dehydration. The enteropathy seems to be part of a systemic disorder that can include neonatal diabetes mellitus, haematological abnormalities, severe allergies and eczema. The syndrome characterised by 'immuno-dysregulation, polyendocrinopathy, autoimmune enteropathy, X-linkage' (IPEX syndrome) is the most severe and also the best characterised form of autoimmune enteropathy. Recently, more has been discovered about the pathophysiology of autoimmune enteropathy. It would seem that an immunological defect exists, which is caused by the non-functioning of regulatory T cells. Characteristic of this disorder are circulating auto-antibodies that cause destruction of the intestinal wall. In a number of patients, this defect is caused by mutations in the Foxp3 gene on the X chromosome. The discovery of the molecular background for autoimmune enteropathy provides important new potential opportunities for diagnosis and therapy. Treatment options for this condition are immunosuppression and bone marrow transplantation.

Metabolic investigations prevent liver transplantation in two young children with citrullinemia type I.

Acute liver failure may be caused by a variety of disorders including inborn errors of metabolism. In those cases, rapid metabolic investigations and adequate treatment may avoid the need for liver transplantation. We report two patients who presented with acute liver failure and were referred to our center for liver transplantation work-up. Urgent metabolic investigations revealed citrullinemia type I. Treatment for citrullinemia type I avoided the need for liver transplantation. Acute liver failure as a presentation of citrullinemia type I has not previously been reported in young children. Although acute liver failure has occasionally been described in other urea cycle disorders, these disorders may be underestimated as a cause. Timely diagnosis and treatment of these disorders may avoid liver transplantation and improve clinical outcome. Therefore, urea cycle disorders should be included in the differential diagnosis in young children presenting with acute liver failure.

Citrulline as a marker for chemotherapy induced mucosal barrier injury in pediatric patients.

BACKGROUND: The currently used National Cancer Institute (NCI) adverse events criteria for mucosal barrier injury (MBI) are insufficient for use in children. We searched for objective, easily measurable indicators for MBI in children with cancer. PURPOSE: In children with acute myeloid leukemia, various MBI-related clinical and laboratory tests were investigated, reflecting clinical severity (NCI symptomatic adverse events criteria (gold standard), daily gut score (DGS)), inflammation (plasma and fecal interleukin-8 (IL-8), fecal calprotectin), enterocytic loss (plasma citrulline, ratio fecal human DNA/total DNA) and intestinal permeability (sugar absorption tests). RESULTS: Intestinal MBI as detected by the NCI adverse events criteria was found in 55% of chemotherapy cycles, correlating well with the continuous DGS (n = 55, rho = 0.581; P < 0.001). Intestinal cell loss as measured by the ratio fecal human DNA/total DNA and plasma citrulline correlated well with both NCI criteria (n = 61, rho = 0.357, P = 0.005 resp. n = 58, rho = -0.482; P < 0.001) and DGS (n = 54, rho = 0.352, P = 0.009 resp. n = 55, rho = -0.625; P < 0.001). Plasma IL-8 correlated strongly to plasma citrulline (n = 46, rho = -0.627; P < 0.001). CONCLUSIONS: MBI was reflected by parameters indicating inflammation (IL-8) and cell loss (plasma citrulline, ratio fecal human DNA/total DNA). We conclude that plasma citrulline might be a good parameter for MBI. Further studies are needed to show whether plasma citrulline can be used as a marker for MBI in future research.

Pediatric Crohn's disease activity at diagnosis, its influence on pediatrician's prescribing behavior, and clinical outcome 5 years later.

BACKGROUND: No studies have been performed in which therapeutic regimens have been compared between mild and moderate-to-severe pediatric Crohn's disease (CD) at diagnosis. The aim was to analyze pediatric CD activity at diagnosis, its influence on pediatrician's prescribing behavior, and clinical outcome 5 years later. METHODS: In a retrospective multicenter study we divided pediatric CD patients at diagnosis into mild or moderate-severe disease. We compared initial therapies, duration of first remission, number of exacerbations, height-for-age and weight-for-height evolvement, and cumulative duration of systemic steroid use in a 5-year follow-up period. RESULTS: Forty-three children were included (25 with mild and 18 with moderate-severe disease). Aminosalicylate monotherapy was more frequently prescribed in the mild group (40% versus 17%; P < 0.01). The median duration of systemic steroid use was 18.3 months in the mild group and 10.4 months in the moderate-severe group (P = 0.09). Duration of first remission was 15.0 months in the mild group and 23.4 months in the moderate-severe group (P = 0.16). The mean number of exacerbations was 2.2 in the mild group and 1.8 in the moderate-severe group (P = 0.28). CONCLUSIONS: CD patients with mild disease were treated with aminosalicylate monotherapy more frequently. These patients, however, tend to have more exacerbations, shorter duration of first remission, and longer total duration of systemic steroid use. Our data support the concept that severity of disease at diagnosis does not reliably predict subsequent clinical course. This study suggests that there is no indication that children with mild CD should be treated differently compared to children with moderate-severe disease.