Razan Alkhouri

Characterization of gut microbiomes in nonalcoholic steatohepatitis (NASH) patients: A connection between endogenous alcohol and NASH

Nonalcoholic steatohepatitis (NASH) is a serious liver disease associated with obesity. Characterized by metabolic syndrome, hepatic steatosis, and liver inflammation, NASH is believed to be under the influence of the gut microflora. Here, the composition of gut bacterial communities of NASH, obese, and healthy children was determined by 16S ribosomal RNA pyrosequencing. In addition, peripheral blood ethanol was analyzed to monitor endogenous ethanol production of patients and healthy controls. UniFrac‐based principle coordinates analysis indicated that most of the microbiome samples clustered by disease status. Each group was associated with a unique pattern of enterotypes. Differences were abundant at phylum, family, and genus levels between healthy subjects and obese patients (with or without NASH), and relatively fewer differences were observed between obese and the NASH microbiomes. Among those taxa with greater than 1% representation in any of the disease groups, Proteobacteria, Enterobacteriaceae, and Escherichia were the only phylum, family and genus types exhibiting significant difference between obese and NASH microbiomes. Similar blood‐ethanol concentrations were observed between healthy subjects and obese non‐NASH patients, but NASH patients exhibited significantly elevated blood ethanol levels. Conclusions: The increased abundance of alcohol‐producing bacteria in NASH microbiomes, elevated blood‐ethanol concentration in NASH patients, and the well‐established role of alcohol metabolism in oxidative stress and, consequently, liver inflammation suggest a role for alcohol‐producing microbiota in the pathogenesis of NASH. We postulate that the distinct composition of the gut microbiome among NASH, obese, and healthy controls could offer a target for intervention or a marker for disease. (HEPATOLOGY 2013)

Vitamin and mineral status in patients with inflammatory bowel disease.

Objectives: Patients with inflammatory bowel disease (IBD) are at risk for vitamin and mineral deficiencies because of long-term inflammation in the gut mucosa and decreased oral intake. The aim of the study is to investigate the prevalence of vitamin and zinc deficiencies in patients with newly diagnosed IBD compared with a control group. Methods: This is a retrospective chart review of all of the patients diagnosed as having IBD from 2006 to 2010, ages 1 to 18 years. Patients who had fat- and water-soluble vitamins (A, E, D 25-OH, folate, and B12) and zinc levels obtained at time of diagnosis were included in the study. A total of 61 patients with IBD and 61 age- and sex-matched controls were included. Results: None of the 61 patients with IBD had folate or vitamin B12 deficiency. Vitamin D deficiency was found in 62% of the patients, vitamin A deficiency in 16%, vitamin E deficiency in 5%, and zinc deficiency in 40%. The control group had vitamin D and E and zinc deficiency in 75%, 8%, and 19% patients, respectively. Conclusions: We conclude that vitamin B12 and folate deficiencies are rare in children with newly diagnosed IBD in the United States and we question whether routine monitoring is warranted. Vitamin A and zinc deficiency are common in patients with newly diagnosed IBD and levels should be assessed at the time of diagnosis so that enteral repletion can commence. Vitamin D deficiency is common in all of the children in the Buffalo, NY, area, and routine screening for this deficiency is warranted.

Structural changes in the gut microbiome of constipated patients

Previous studies using culture-based methods suggested an association between constipation and altered abundance of certain taxa of the colonic microbiome. We aim to examine the global changes in gut microbial composition of constipated patients. A cross-sectional pilot study using 16S rRNA gene pyrosequencing was performed to compare stool microbial composition of eight constipated patients and 14 nonconstipated controls. Only obese children were enrolled so that the microbiome features associated with constipation would not be obscured by those associated with obesity. The sequencing reads were processed by QIIME for quantitative analysis of the microbial composition at genus and above levels. Dietary intake for all the individuals was assessed by dietary recalls and a food frequency questionnaire. The ecological diversities of fecal microbiome of the constipated patients differed from those of the controls. Significantly decreased abundance in Prevotella and increased representation in several genera of Firmicutes were observed in constipated patients compared with controls. The conventional probiotic genera Lactobacillus and Bifidobacteria were not decreased in the microbiomes of the constipated patients. These alterations in the fecal microbiome of constipated patients suggested that a novel probiotic treatment including certain Prevotella strains may be more effective than conventional probiotic products incorporating Lactobacillus or Bifidobacterium species. While it is possible that the observed changes in the microbiome in constipated subjects are a consequence of a low-fiber diet, these changes also predict a different pattern of bacterial fermentation end-products, such as increased butyrate production, which may contribute to pathogenesis of constipation.

Effect of Dietary Advanced Glycation End Products on Mouse Liver

The exact pathophysiology of non-alcoholic steatohepatitis (NASH) is not known. Previous studies suggest that dietary advanced glycation end products (AGEs) can cause oxidative stress in liver. We aim to study the effects of dietary AGEs on liver health and their possible role in the pathogenesis of NASH. METHODS: Two groups of mice were fed the same diet except the AGE content varied. One group was fed a high AGE diet and the second group was fed a regular AGE diet. Liver histology, alanine aminotransferase, aspartate aminotransferase, fasting glucose, fasting insulin, insulin resistance and glucose tolerance were assessed. RESULTS: Histology revealed that neutrophil infiltration occurred in the livers of the high AGE group at week 26; steatosis did not accompany liver inflammation. At week 39 livers from both groups exhibited macro- or micro-steatosis, yet no inflammation was detected. Higher insulin levels were detected in the regular AGE group at week 26 (P = 0.034), compared to the high AGE group. At week 39, the regular AGE group showed higher levels of alanine aminotransferase (P<0.01) and aspartate aminotransferase (P = 0.02) than those of the high AGE group. CONCLUSIONS: We demonstrate that a high AGE diet can cause liver inflammation in the absence of steatosis. Our results show that dietary AGEs could play a role in initiating liver inflammation contributing to the disease progression of NASH. Our observation that the inflammation caused by high AGE alone did not persist suggests interesting future directions to investigate how AGEs contribute to pro-oxidative and anti-oxidative pathways in the liver.

Endotoxemia unrequired in the pathogenesis of pediatric nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH), the severe form of nonalcoholic fatty liver disease, is a serious liver complication associated with obesity. Several studies suggest that endotoxemia is associated with nonalcoholic fatty liver disease and NASH. We aimed to study the correlation of gut microbiome composition and the incidence of endotoxemia in obese patients and NASH patients in comparison with normal controls.

Vitamin and zinc status pretreatment and posttreatment in patients with inflammatory bowel disease.

ABSTRACT Vitamin deficiencies are common in inflammatory bowel disease. Here we present 5-year follow-up data of 61 patients. No folate or vitamin B12 deficiency was identified throughout the study. A daily multivitamin supplement was sufficient to replete 100% of vitamin A–deficient and vitamin E–deficient patients. A total of 52% of vitamin D–deficient patients corrected, but 15% who had normal vitamin D levels at diagnosis developed deficiency. A total of 63% of zinc-deficient patients normalized their zinc status, but 15% developed zinc deficiency at follow-up despite supplementation.

Identification of meckel diverticulum by capsule endoscopy.

p JP A 5-year-old white boy with a medical history of constipation presented with a 1-day history of painless hematochezia. He had 2 episodes of bright-red blood in his stool with clots. Initial laboratory evaluation was positive for hemoglobin of 7.9, hemoccult-positive stool, and 2 negative Meckel scans after 5-day pretreatment with ranitidine (1). An upper endoscopy and colonoscopy were visually and histologically normal. Capsule endoscopy showing 2 lumens within the ileum was consistent with Meckel diverticulum (MD) (Fig. 1). The patient underwent an exploratory laparoscopy; an MD was found and removed (2). The presence of the enteric wall biopsy showing a layering architecture composed of villiform small intestinal mucosa and gastric oxyntic mucosa with focal ulceration on histological evaluation confirmed an MD. Capsule endoscopy, which is not the conventional method of detecting MD, can aid in identifying MD in patients whose previous evaluations are negative. Definitive treatment for MD is surgical removal in the symptomatic patient.

Outcome of medical management of intraabdominal abscesses in children with Crohn disease

INTRODUCTION Crohn disease (CD) is a chronic inflammatory condition of the gastrointestinal tract that is complicated by fistulas, strictures, and intraabdominal abscesses (IAA) in 10%-30% of patients. To avoid surgical resection of the bowel, medical therapy with antibiotics (Ab) with or without percutaneous drainage (PD) is first undertaken. Our objectives are to examine the outcome of IAA in CD patients treated with antibiotics alone vs antibiotics and PD, and to identify risk factors for medical therapy failure. METHODS Charts for patient with CD who were diagnosed between 2004 and 2016 at the Women and Childrens Hospital of Buffalo were retrospectively reviewed. We compared the two modalities of medical therapy (Ab + PD vs Ab alone) in terms of abscess resolution and the need for surgical intervention. RESULTS Twenty-nine patients, ages ranging from 12 to 18years, mean 15.5±2.5, 48% Male with IAA were identified. Overall, 69% of abscesses failed medical therapy including 87% of the drained abscesses and 50% of nondrained abscesses, p=0.04. The abscesses that failed medical therapy were more likely to have been drained (P=0.03) as they were larger in size (P = 0.03), patients were more likely to have a known CD on immunosuppression (P=0.016), and more likely to have an associated upper GI disease (P=0.002), when compared to those that were successful with medical therapy alone. CONCLUSION Our results show that the majority of our patients required surgical intervention for abscess treatment and resolution of associated findings despite drainage. Risk factors include big drainable abscesses, developing IAA while on immunosuppression, and a more extensive disease with associated fistulae and strictures. Small undrainable abscesses are likely to resolve with antibiotics alone, therefore early detection and treatment are essential. TYPE OF STUDY Level 2, retrospective study.

Paraoxonase Gene Expression in Pediatric Inflammatory Bowel Disease

Background: Oxidative stress plays a role in the pathogenesis of inflammatory bowel disease (IBD). The Paraoxonase (PON) genes, expressed in the human intestine, are thought to prevent oxidative stress and modulate inflammation. We investigated the effect of IBD and steroids on PON gene. We hypothesized that PON gene expression is decreased in IBD patients and that steroid treatment would return it to normal.Methods: Pediatric patients diagnosed with IBD, were enrolled and matched to control subjects. For in vitro studies, human epithelial colorectal adenocarcinoma (Caco-2) cells were treated with hydrogen peroxide (H2O2) and dexamethasone. PON genes expression was evaluated by quantitative real-time PCR for both the biopsies and the Caco-2 cells.Results: PON gene expression was decreased in intestinal biopsies from medication naive IBD patients when compared to controls (p<0.05). Biopsies from IBD patients on steroids exhibited up regulation of PON gene expression (p<0.05). Caco-2 cells treated with H2O2 had decreased PON gene expression compared to controls (p<0.05). Dexamethasone increased PON gene expression in Caco-2 cells (p<0.05).Conclusion: Our data suggests that decreased PON expression in IBD patients is a consequence of oxidative stress which plays a role in the pathogenesis of IBD. Further, steroids counteract the effect of oxidative stress by up regulating PON gene expression. PON genes may be targets for the management of intestinal diseases like IBD.

Esophagitis in children with celiac disease.

Objectives. To our knowledge, the occurrence of esophagitis in children with celiac disease (CD) has never been evaluated. The aim of this study is to determine the prevalence of esophagitis in children with CD. Patients and Methods. Between 2003 and 2007, children with biopsy confirmed CD were retrospectively identified. Biopsy reports were reviewed for esophageal inflammation. Biopsy reports of 2218 endoscopies performed during the same period were also evaluated for inflammation. Results. Forty-nine children diagnosed with CD (47% boys). Nineteen of 49 (39%) patients with CD had esophagitis (95% CI 0.23–0.5). Thirty percent of boys and 46% of girls with CD had esophagitis (95% CI 0.12–0.40). Overall, 45% of patients who underwent upper endoscopy had esophagitis. The prevalence of esophagitis in CD (39%) compared to the prevalence of esophagitis (45%) in our practice was not significantly different, P = 0.2526. Conclusion. There was no difference in the prevalence of esophagitis between children diagnosed with CD at the time of their diagnostic EGD and the prevalence of esophagitis in children without CD. A prospective study to determine whether the esophagitis should be treated with acid suppression or whether the esophagitis heals with the gluten-free diet is warranted.