The influence of vitamin D on M1 and M2 macrophages in patients with Crohn's disease.

Defective bacterial clearance by macrophages plays an important role in Crohn's disease (CD). Phenotypes and functions of inflammatory M1 and anti-inflammatory M2 have not been studied in CD. Vitamin D supplementation reduces the severity of CD by unclear mechanisms. We studied macrophage characteristics in CD and controls and the effects of 1,25 vitamin D (1,25D). PBMC were isolated from CD patients and controls. M1 and M2 were generated by culturing of monocytes with GM-CSF and M-CSF, respectively. CD M1 and M2 showed normal phagocytosis and chemotaxis to CCL2 and fMLP. LPS-induced production of TNF-α, IL-12p40 and IL-10 was comparable between groups. Phagocytosis was unaltered with 1,25D; migration only increased marginally. M1 produced more IL-12p40 and TNF-α; IL-10 was greater in M2. 1,25D markedly decreased IL-12p40 by M1 and M2. 1,25D decreased TNF-α in CD M1; IL-10 levels were unaffected. M2 express F13A1, PTGS2, CD163, CXCL10, CD14 and MMP2, whereas TGF-ß, CCL1 and CYP27B1 expression was higher in M1. Marker expression was similar between CD and controls. M1 and M2 markers were not differentially modulated by 1,25D. CD macrophages are not functionally or phenotypically different vs. CONTROLS: 1,25D markedly decreased pro-inflammatory M1 cytokines but did not modulate polarization to anti-inflammatory M2 phenotype.

Vitamin D Reduces Colitis- and Inflammation-Associated Colorectal Cancer in Mice Independent of NOD2.

Inflammatory bowel disease (IBD) patients are at increased risk of developing colorectal cancer (CRC). Vitamin D (vD) induces NOD2 gene expression, enhancing immunity, while deficiency impairs intestinal epithelial integrity, increasing inflammation. This study investigated the effect of vD on CRC in colitis, and if preventive benefits are mediated via NOD2. Inflammation-associated CRC was induced by treating C57BL/6J and Nod2-/- mice with azoxymethane (AOM) and dextran sodium sulfate (DSS) cycles (×3). vD-deficient mice displayed more severe colitis compared to vD-supplemented mice, with greater weight loss, higher colitis activity index, increased colonic weight/length ratios, and lower survival rates. Increased histological inflammation score and increased IL-6 were observed in the mucosa of vD-deficient mice. Overall incidence of colonic tumors was not significantly different between vD-deficient and vD-supplemented mice. Higher tumor multiplicity was observed in vD-deficient vs vD-supplemented groups (both mouse strains). After AOM/DSS treatment, decreased plasma 25(OH)D3 levels and downregulation of vD target genes Cyp24 and Vdr were observed in both mice strains (vD-deficient or vD-supplemented diet), compared to saline-treated controls on the vD-deficient diet. In conclusion, vD supplementation reduced colitis severity and decreased the number of inflammation-associated colorectal tumors in both C57BL/6J and Nod2-/- mice, independent of NOD2.

Studies on the chemopreventive effect of carnitine on tumorigenesis in vivo, using two experimental murine models of colon cancer.

Carnitine is known for its essential role in intermediary metabolism. In vitro studies suggest that its antioxidant and anti-inflammatory properties are potentially beneficial toward cancer prevention. This study tested effects of carnitine on the development of colon cancer in vivo using 2 murine models: azoxymethane (AOM) treatment as a model of carcinogen-induced colon cancer and a genetically induced model using Apc (Min/+) mice. AOM and Apc (Min/+) mice divided into dietary groups varying in lipid content, with or without carnitine supplementation (0.08%). AOM-exposed mice on a high butterfat diet had significantly increased aberrant crypts (ACF) (9.3 ± 0.88 vs. 6.3 ± 0.65), and macroscopic tumors (3.8 ± 0.95 vs. 2.0 ± 0.25) compared to mice on a control diet. In AOM mice fed the high butterfat diet, carnitine supplementation inhibited ACF (4.9 ± 0.7 vs. 9.3 ± 0.88, P < 0.001), crypt multiciplicity (1.6 ± 0.08 vs. 1.92 ± 0.1, P < 0.01) and tumors (1.5 ± 0.38 vs. 3.8 ± 0.95, P < 0.001). Carnitine supplementation resulted in significantly increased tissue carnitine and acylcarnitine levels. Carnitine inhibited the development of precancerous lesions and macroscopic colonic tumors in AOM-treated mice. However, carnitine did not exert protective effects on intestinal tumors in Apc (Min/+) mice.

Indications for the use of probiotics in gastrointestinal diseases.

Probiotics are live microbial organisms that are present in foods or dietary supplements and that confer health benefits to the host when ingested in sufficient quantities. Probiotics can be bacterial (e.g. Bifidobacteria spp. and Lactobacillus spp.) or yeasts (e.g. Saccharomyces boulardii). The administration of probiotics is often believed to be by and large beneficial for individuals with inflammatory or infectious diseases of the gastrointestinal tract. These positive effects are generally attributed to the ability of probiotics to regulate intestinal permeability, normalize host intestinal flora, improve gut immune barrier function, and equilibrate the balance between proinflammatory and anti-inflammatory cytokines. Of note, however, these claims are not always substantiated by findings from properly conducted clinical trials. Of particular importance, even when results from randomized controlled trials support the beneficial effects of a particular probiotic for a specific indication, the benefits achieved by the probiotic are generally not translatable to other probiotic formulations. This review discusses the gastrointestinal indications for probiotic use and describes the level of evidence that supports the use of specific probiotics for these indications. Several indications are addressed, including enteric infections, gastritis caused by Helicobacter pylori infection, necrotizing enterocolitis, inflammatory bowel diseases, and irritable bowel syndrome.

Gene-expression profile analysis in the mid-gestation human intestine discloses greater functional immaturity of the colon as compared with the ileum.

BACKGROUND AND OBJECTIVES: The occurrence of many neonatal inflammatory intestinal diseases in preterm infants highlights the susceptibility of the immature intestine to responding inadequately to nutrients and microbes. A better understanding of functional intestinal development is essential for the design of optimal treatments ensuring survival and growth of premature infants. The purpose of this study was to evaluate the gene expression profiles of the human ileum and colon at mid-gestation because these 2 segments are considered to be similar at this stage and are the sites of the most frequent pathologies in preterm infants. SUBJECTS AND METHODS: We compared the gene-expression profiles of human fetal small and large intestines using a cDNA microarray and analyzed the data with Ingenuity Pathway Analysis software. RESULTS: We found that a significant proportion of the genes was differentially expressed in the 2 segments. Gene cluster analysis revealed an even higher level of transcriptional dissimilarity at the functional level. For instance, segment-specific/overexpressed gene clusters in the ileum included genes involved with amino acid, vitamin, and mineral metabolism, reflecting the higher level of maturity of the small intestine as compared with the colon in which genes involved with cell cycle, cell death, and cell signaling were the predominant clusters of genes expressed. CONCLUSIONS: Functional clustering analysis of the differentially expressed genes revealed important functional differences between the 2 segments and a relative immaturity of the colon, suggesting that already at mid-gestation, the 2 intestinal segments should be considered as 2 distinct organs.

Direct and indirect induction by 1,25-dihydroxyvitamin D3 of the NOD2/CARD15-defensin beta2 innate immune pathway defective in Crohn disease.

Vitamin D signaling through its nuclear vitamin D receptor has emerged as a key regulator of innate immunity in humans. Here we show that hormonal vitamin D, 1,25-dihydroxyvitamin D(3), robustly stimulates expression of pattern recognition receptor NOD2/CARD15/IBD1 gene and protein in primary human monocytic and epithelial cells. The vitamin D receptor signals through distal enhancers in the NOD2 gene, whose function was validated by chromatin immunoprecipitation and chromatin conformation capture assays. A key downstream signaling consequence of NOD2 activation by agonist muramyl dipeptide is stimulation of NF-kappaB transcription factor function, which induces expression of the gene encoding antimicrobial peptide defensin beta2 (DEFB2/HBD2). Pretreatment with 1,25-dihydroxyvitamin D(3) synergistically induced NF-kappaB function and expression of genes encoding DEFB2/HBD2 and antimicrobial peptide cathelicidin in the presence of muramyl dipeptide. Importantly, this synergistic response was also seen in macrophages from a donor wild type for NOD2 but was absent in macrophages from patients with Crohn disease homozygous for non-functional NOD2 variants. These studies provide strong molecular links between vitamin D deficiency and the genetics of Crohn disease, a chronic incurable inflammatory bowel condition, as Crohn's pathogenesis is associated with attenuated NOD2 or DEFB2/HBD2 function.

Imbalances in dietary consumption of fatty acids, vegetables, and fruits are associated with risk for Crohn's disease in children.

BACKGROUND AND OBJECTIVES: The role of dietary factors in the etiology of Crohn's disease (CD) is inconsistent largely due to difficulties in acquiring valid information on consumption habits. We examined the impact of diet on new onset CD in children using a validated food-frequency questionnaire (FFQ). METHODOLOGY: A case-control study was carried out. Children < or =20 yr, newly diagnosed with CD, were recruited from 3 pediatric gastroenterology clinics across Canada. Population or hospital controls were selected matched to cases for time of diagnosis (+/-6 months) and area of residence. Dietary consumption 1 yr prior to disease diagnosis was evaluated using a validated FFQ, administered within 1 month of diagnosis. Conditional logistic regression analysis adjusting for potential confounding variables (energy intake, age, gender, body mass index) was carried out. RESULTS: A total of 130 CD patients and 202 controls were studied. Mean age at diagnosis (+/-SD) was 14.2 (2.7). There were more male patients (59%). Comparing the highest to the lowest levels of consumption, higher amounts of vegetables (OR 0.69, 95% CI 0.33-1.44, P= 0.03), fruits (OR 0.49, 95% CI 0.25-0.96, P= 0.02), fish (OR 0.46, 95% CI 0.20-1.06, P= 0.02), and dietary fiber (OR 0.12, 95% CI 0.04-0.37, P < 0.001) protected from CD. Consumption of long-chain omega-3 fatty acids (LCN-omega-3) was negatively associated with CD (OR 0.44, 95% CI 0.19-1.00, P < 0.001). A higher ratio of LCN-omega-3/omega-6 fatty acids was significantly associated with lower risks for CD (OR 0.32, 95% CI 0.14-0.71, P= 0.02). CONCLUSIONS: Our findings indicate that an imbalance in consumption of fatty acids, vegetables, and fruits is associated with increased risks for CD among Canadian children.

Guideline for the diagnosis and treatment of celiac disease in children: recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition.

Celiac disease is an immune-mediated enteropathy caused by a permanent sensitivity to gluten in genetically susceptible individuals. It occurs in children and adolescents with gastrointestinal symptoms, dermatitis herpetiformis, dental enamel defects, osteoporosis, short stature, delayed puberty and persistent iron deficiency anemia and in asymptomatic individuals with type 1 diabetes, Down syndrome, Turner syndrome, Williams syndrome, selective immunoglobulin (Ig)A deficiency and first degree relatives of individuals with celiac disease. The Celiac Disease Guideline Committee of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition has formulated a clinical practice guideline for the diagnosis and treatment of pediatric celiac disease based on an integration of a systematic review of the medical literature combined with expert opinion. The Committee examined the indications for testing, the value of serological tests, human leukocyte antigen (HLA) typing and histopathology and the treatment and monitoring of children with celiac disease. It is recommended that children and adolescents with symptoms of celiac disease or an increased risk for celiac disease have a blood test for antibody to tissue transglutaminase (TTG), that those with an elevated TTG be referred to a pediatric gastroenterologist for an intestinal biopsy and that those with the characteristics of celiac disease on intestinal histopathology be treated with a strict gluten-free diet. This document represents the official recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition on the diagnosis and treatment of celiac disease in children and adolescents.

Transitioning the paediatric IBD patient to adult care.

Transitioning an adolescent patient to an internist/gastroenterologist's care requires an understanding of the specific issues and challenges involved in the diagnosis and management of paediatric inflammatory bowel disease (IBD). Even though diagnostic criteria, as well as methods are the same in children and adults, younger patients may experience more insidious presentations. A high level of suspicion is necessary for an early and accurate diagnosis. Management of IBD in the paediatric population begins with the assessment of disease extent and activity as well as the identification of potentially serious complications (such as malnutrition, growth/sexual retardation and osteoporosis), which are often present at the time of diagnosis. Treatment includes not only medical, nutritional or surgical therapy but also a multidisciplinary or holistic approach taking into consideration the psychological as well as social impact of the disease on the patient and family.