Anti-inflammatory effect of a pomegranate extract on LPS-stimulated HepG2 cells.

Pomegranate is an important source of bioactive molecules with proven beneficial effects on human health. The aim of this study was to investigate the potential anti-inflammatory effect of a pomegranate extract (PE), obtained from the whole fruit and previously characterized by Reversed Phase-Ultra High-Pressure Liquid Chromatography-High Resolution Mass Spectrometry (RP-UHPLC-HRMS), on HepG2 human hepatocellular carcinoma cells challenged with the lipopolysaccharide (LPS). In LPS-treated cells (1 µg/ml, 24h), the PE treatment (administered at the non-cytotoxic dose of 1 µg/ml, 24h) induced a significant reduction of three key pro-inflammatory cytokines, i.e. interleukin-8 (IL-8), interleukin-1 beta (IL-1ß) and tumor necrosis factor-alpha (TNF-α), at both gene expression (as assayed by real-time PCR) and secretion levels (by Enzyme-linked Immunosorbent Assay, ELISA). Although further in vivo studies are needed to prove its efficacy, this preliminary in vitro study suggests that the PE might be useful for ameliorating liver inflammation.

The ethanolic extract of Corylus avellana L. drives a microRNA-based cytotoxic effect on HepG2 hepatocarcinoma cells.

An ethanolic extract of Corylus avellana L. hazelnut was characterised by liquid chromatography coupled to high resolution mass spectrometry. We here evaluated the in vitro cytotoxic response to such extract in HepG2 cells and tried to depict the underlying mechanism(s) in terms of microRNA-34b/c involvement. Following long-term exposure (144h) of HepG2 cells with 0.04-0.4 mg/ml of hazelnut extract, we demonstrated that miR-34 precursor RNA and both mature miR-34b and miR-34c molecules underwent a significant stimulation (>2-fold change, p < 0.05) in cells treated with the highest concentration. The epigenetic modulation was accompanied by the inhibition of cell proliferation, the decrease of viability and activation of apoptosis at 144h of treatment with 0.4 mg/ml of hazelnut.These in vitro findings demonstrate the cytotoxic effect of the C. avellana extract in HepG2 cells and open the way to in vivo validation of possible application of hazelnut-based extracts, and/or its metabolites, as promising epigenetics drugs.

Effect of Citrus bergamia extract on lipid profile: A combined in vitro and human study.

With the aim of characterising the hypo-lipidemic function of the Brumex™ ingredient obtained from the whole fruit of Citrus bergamia, a combined pre-clinical and clinical study was conducted. In the HepG2 experimental model, we first demonstrated that Brumex™ does not trigger any significant alteration in cell viability over the tested concentration range of 1-2000 µg/mL (4 and 24 h). By stimulating the phosphorylation of AMP-activated protein kinase (AMPK) at threonine 172, Brumex™ significantly reduces both cholesterol and triglyceride (TG) intracellular content of HepG2 cells and impairs the expression levels of lipid synthesis-related genes (namely, SREBF1c, SREBF2, ACACA, SCD1, HMGCR and FASN). In vitro data have been validated in a dedicated double-blind, placebo-controlled, randomised clinical trial performed in 50 healthy moderately hyper-cholesterolemic subjects, undergoing supplementation with either Brumex™ (400 mg) or placebo for 12 weeks. Clinical and blood laboratory data were evaluated at the baseline and at the end of the trial. Brumex™ positively impacted on both plasma lipid pattern and liver enzymes compared with the placebo, mainly in terms of significant reduction of total cholesterol (TC), TG, low-density lipoprotein-cholesterol (LDL-C), non-high-density lipoprotein-cholesterol (non-HDL-C), apolipoprotein B100 (ApoB), fasting plasma glucose (FPG), glutamic-oxaloacetic transaminase (GOT), glutamate pyruvate transaminase (GPT) and gamma-glutamyl-transferase (gGT).

The interaction of DNMT1 and DNMT3A epigenetic enzymes with phthalates and perfluoroalkyl substances: an in silico approach.

The occurrence of long-lasting adverse effects of the environmental contaminants on human health is a current emerging issue. In particular, phthalates, poly- and perfluoroalkyl substances are proposed to trigger toxic effects as well as persistent changes on human development and metabolism by different mechanisms, including epigenetic modifications, although the specific underlying pathways are still unknown. This study contributes to identify the potential molecular initiating events of epigenetic-mediated adverse effects by an in silico approach, which combines molecular docking and molecular dynamics simulation. The approach probes the potential molecular interaction between several different phthalates and persistent organic pollutants and a specific class of epigenetic modulators, namely the DNA methyltransferases (DNMTs). The dynamics of interaction and the binding free energies of the ligand-DNMTs complexes demonstrated that pollutants can be classified into two main groups, according to the ligand-target complex stability: (1) a larger class of phthalates (DBP, DEHP, MBP and MEHP) acting as inhibitors of the enzymatic activity of the epigenetic targets and (2) a smaller class of phthalates (DMP and MMP) and perfluoroalkyl substances (PFOA and PFOS) which do not interact stably with the human DNMTs. These findings provide the first valuable in silico insights on the ability of these specific environmental pollutants to directly bind and inhibit a key class of epigenetic regulators. Communicated by Ramaswamy H. Sarma.

Acute Neurotoxicity of Antisense Oligonucleotides After Intracerebroventricular Injection Into Mouse Brain Can Be Predicted from Sequence Features.

Antisense oligonucleotides are a relatively new therapeutic modality and safety evaluation is still a developing area of research. We have observed that some oligonucleotides can produce acute, nonhybridization dependent, neurobehavioral side effects after intracerebroventricular (ICV) dosing in mice. In this study, we use a combination of in vitro, in vivo, and bioinformatics approaches to identify a sequence design algorithm, which can reduce the number of acutely toxic molecules synthesized and tested in mice. We find a cellular assay measuring spontaneous calcium oscillations in neuronal cells can predict the behavioral side effects after ICV dosing, and may provide a mechanistic explanation for these observations. We identify sequence features that are overrepresented or underrepresented among oligonucleotides causing these reductions in calcium oscillations. A weighted linear combination of the five most informative sequence features predicts the outcome of ICV dosing with >80% accuracy. From this, we develop a bioinformatics tool that allows oligonucleotide designs with acceptable acute neurotoxic potential to be identified, thereby reducing the number of toxic molecules entering drug discovery pipelines. The informative sequence features we identified also suggest areas in which to focus future medicinal chemistry efforts.

Exposure of the SH-SY5Y Human Neuroblastoma Cells to 50-Hz Magnetic Field: Comparison Between Two-Dimensional (2D) and Three-Dimensional (3D) In Vitro Cultures.

We here characterize the response to the extremely low-frequency (ELF) magnetic field (MF, 50 Hz, 1 mT) of SH-SY5Y human neuroblastoma cells, cultured in a three-dimensional (3D) Alvetex® scaffold compared to conventional two-dimensional (2D) monolayers. We proved that the growing phenotype of proliferating SH-SY5Y cells is not affected by the culturing conditions, as morphology, cell cycle distribution, proliferation/differentiation gene expression of 3D-cultures overlap what reported in 2D plates. In response to 72-h exposure to 50-Hz MF, we demonstrated that no proliferation change and apoptosis activation occur in both 2D and 3D cultures. Consistently, no modulation of Ki67, MYCN, CCDN1, and Nestin, of invasiveness and neo-angiogenesis-controlling genes (HIF-1α, VEGF, and PDGF) and of microRNA epigenetic signature (miR-21-5p, miR-222-3p and miR-133b) is driven by ELF exposure. Conversely, intracellular glutathione content and SOD1 expression are exclusively impaired in 3D-culture cells in response to the MF, whereas no change of such redox modulators is observed in SH-SY5Y cells if grown on 2D monolayers. Moreover, ELF-MF synergizes with the differentiating agents to stimulate neuroblastoma differentiation into a dopaminergic (DA) phenotype in the 3D-scaffold culture only, as growth arrest and induction of p21, TH, DAT, and GAP43 are reported in ELF-exposed SH-SY5Y cells exclusively if grown on 3D scaffolds. As overall, our findings prove that 3D culture is a more reliable experimental model for studying SH-SY5Y response to ELF-MF if compared to 2D conventional monolayer, and put the bases for promoting 3D systems in future studies addressing the interaction between electromagnetic fields and biological systems.

NOD2 and inflammation: current insights.

The nucleotide-binding oligomerization domain (NOD) protein, NOD2, belonging to the intracellular NOD-like receptor family, detects conserved motifs in bacterial peptidoglycan and promotes their clearance through activation of a proinflammatory transcriptional program and other innate immune pathways, including autophagy and endoplasmic reticulum stress. An inactive form due to mutations or a constitutive high expression of NOD2 is associated with several inflammatory diseases, suggesting that balanced NOD2 signaling is critical for the maintenance of immune homeostasis. In this review, we discuss recent developments about the pathway and mechanisms of regulation of NOD2 and illustrate the principal functions of the gene, with particular emphasis on its central role in maintaining the equilibrium between intestinal microbiota and host immune responses to control inflammation. Furthermore, we survey recent studies illustrating the role of NOD2 in several inflammatory diseases, in particular, inflammatory bowel disease, of which it is the main susceptibility gene.

Transcription Factor ZNF281: A Novel Player in Intestinal Inflammation and Fibrosis.

Background and aims: Recent evidences reveal the occurrence of a close relationship among epithelial to mesenchymal transition (EMT), chronic inflammation and fibrosis. ZNF281 is an EMT-inducing transcription factor (EMT-TF) involved in the regulation of pluripotency, stemness, and cancer. The aim of this study was to investigate in vitro, in vivo, and ex vivo a possible role of ZNF281 in the onset and progression of intestinal inflammation. A conceivable contribution of the protein to the development of intestinal fibrosis was also explored. Methods: Human colorectal adenocarcinoma cell line, HT29, and C57BL/6 mice were used for in vitro and in vivo studies. Mucosal biopsy specimens were taken during endoscopy from 29 pediatric patients with Crohn's disease (CD), 24 with ulcerative colitis (UC) and 16 controls. ZNF281 was knocked down by transfecting HT29 cells with 20 nM small interference RNA (siRNA) targeting ZNF281 (siZNF281). Results: We show for the first time that ZNF281 is induced upon treatment with inflammatory agents in HT29 cells, in cultured uninflamed colonic samples from CD patients and in DSS-treated mice. ZNF281 expression correlates with the disease severity degree of CD and UC patients. Silencing of ZNF281 strongly reduces both inflammatory (IL-8, IL-1beta, IL-17, IL-23) and EMT/fibrotic (SNAIL, Slug, TIMP-1, vimentin, fibronectin, and α-SMA) gene expression; besides, it abolishes the increase of extracellular-collagen level as well as the morphological modifications induced by inflammation. Conclusions: The identification of transcription factor ZNF281 as a novel player of intestinal inflammation and fibrosis allows a deeper comprehension of the pathogenetic mechanisms underlying inflammatory bowel disease (IBD) and provide a new target for their cure.

RIP3 AND pMLKL promote necroptosis-induced inflammation and alter membrane permeability in intestinal epithelial cells.

BACKGROUND: Necroptosis is an inflammatory form of programmed cell death requiring receptor-interacting protein kinase 3 (RIP3) and mixed lineage kinase domain-like protein (MLKL). AIMS: The aim of this study is to examine in depth in vitro and ex vivo the contribution of necroptosis to intestinal inflammation. METHODS: In vitro: we used an intestinal cell line, HCT116RIP3, produced in our laboratory and overexpressing RIP3. Ex vivo: intestinal mucosal biopsies were taken from patients with inflammatory bowel disease (IBD) (20 with Crohn's disease; 20 with ulcerative colitis) and from 20 controls. RESULTS: RIP3-induced necroptosis triggers MLKL activation, increases cytokine/alarmin expression (IL-8, IL-1ß, IL-33, HMGB1), NF-kBp65 translocation and NALP3 inflammasome assembly. It also affects membrane permeability by altering cell-cell junctional proteins (E-cadherin, Occludin, Zonulin-1). Targeting necroptosis through Necrostatin-1 significantly reduces intestinal inflammation in vitro and in cultured intestinal explants from IBD. CONCLUSION: We show for the first time in vitro and ex vivo that RIP3-driven necroptosis seriously affects intestinal inflammation by increasing pMLKL, activating different cytokines and alarmins, and altering epithelial permeability. The inhibition of necroptosis causes a significant decrease of all these effects. These data strongly support the view that targeting necroptosis may represent a promising new option for the treatment of inflammatory enteropathies.

NOD2 induces autophagy to control AIEC bacteria infectiveness in intestinal epithelial cells.

OBJECTIVE: The importance of autophagy in mechanisms underlying inflammation has been highlighted. Downstream effects of the bacterial sensor NOD2 include autophagy induction. Recently, a relationship between defects in autophagy and adherent/invasive Escherichia coli (AIEC) persistence has emerged. The present study aims at investigating the interplay between autophagy, NOD2 and AIEC bacteria and assessing the expression level of autophagic proteins in intestinal biopsies of pediatric patients with inflammatory bowel disease (IBD). METHODS: A human epithelial colorectal adenocarcinoma (Caco2) cell line stably over-expressing NOD2 was produced (Caco2NOD2). ATG16L1, LC3 and NOD2 levels were analysed in the Caco2 cell line and Caco2NOD2 after exposure to AIEC strains, by western blot and immunofluorescence. AIEC survival inside cells and TNFα, IL-8 and IL-1ßmRNA expression were analysed by gentamicin protection assay and real time PCR. ATG16L1 and LC3 expression was analyzed in the inflamed ileum and colon of 28 patients with Crohn's disease (CD), 14 with ulcerative colitis (UC) and 23 controls by western blot. RESULTS: AIEC infection increased ATG16L1 and LC3 in Caco2 cells. Exposure to AIEC strains increased LC3 and ATG16L1 in Caco2 overexpressing NOD2, more than in Caco2 wild type, while a decrease of AIEC survival rate and cytokine expression was observed in the same cell line. LC3 expression was increased in the inflamed colon of CD and UC children. CONCLUSIONS: The NOD2-mediated autophagy induction is crucial to hold the intramucosal bacterial burden, especially towards AIEC, and to limit the resulting inflammatory response. Autophagy is active in inflamed colonic tissues of IBD pediatric patients.

The Identification and Pharmacological Characterization of 6-(tert-Butylsulfonyl)-N-(5-fluoro-1H-indazol-3-yl)quinolin-4-amine (GSK583), a Highly Potent and Selective Inhibitor of RIP2 Kinase.

RIP2 kinase is a central component of the innate immune system and enables downstream signaling following activation of the pattern recognition receptors NOD1 and NOD2, leading to the production of inflammatory cytokines. Recently, several inhibitors of RIP2 kinase have been disclosed that have contributed to the fundamental understanding of the role of RIP2 in this pathway. However, because they lack either broad kinase selectivity or strong affinity for RIP2, these tools have only limited utility to assess the role of RIP2 in complex environments. We present, herein, the discovery and pharmacological characterization of GSK583, a next-generation RIP2 inhibitor possessing exquisite selectivity and potency. Having demonstrated the pharmacological precision of this tool compound, we report its use in elucidating the role of RIP2 kinase in a variety of in vitro, in vivo, and ex vivo experiments, further clarifying our understanding of the role of RIP2 in NOD1 and NOD2 mediated disease pathogenesis.

NOD2 Is Regulated By Mir-320 in Physiological Conditions but this Control Is Altered in Inflamed Tissues of Patients with Inflammatory Bowel Disease.

BACKGROUND: Large evidence supports the role of microRNAs as new important inflammatory mediators by regulating both the adaptive and innate immunity. In the present study, we speculated that miR-320 controls NOD2 (nucleotide-binding oligomerization domain) expression, because it contains multiple binding sites in the 3'-untranslated region of the gene. NOD2, the first gene associated to increased susceptibility to Crohn's disease, is a cytosolic receptor that senses wall peptides of bacteria and promotes their clearance through initiation of a proinflammatory transcriptional program. This study aims at demonstrating that NOD2 is a target of miR-320 as well as investigating the role of inflammation in modulating the miR-320 control on NOD2 expression and analyzing miR-320 expression in intestinal biopsies of children with inflammatory bowel disease. METHODS: The colonic adenocarcinoma cell line HT29 was used to assess the miR-320-mediated regulation of NOD2 expression. MiR-320 and NOD2 expression were analyzed in mucosal samples of 40 children with inflammatory bowel disease. RESULTS: During inflammation, NOD2 expression is inversely correlated with miR-320 expression in vitro and ex vivo. Exogenous miR-320 transfection in HT29 cells leads to a significant decrease of NOD2 expression, whereas the miR-320 inhibitor transfection leads to increase of NOD2 expression, nuclear translocation of nuclear factor κB, and activation of downstream cytokines. CONCLUSIONS: We show for the first time that NOD2 expression is under the control of miR-320. We also show in vitro and ex vivo that inflammation induces a decrease of miR-320 and the latter correlates negatively with NOD2 expression.

Dipotassium glycyrrhizate via HMGB1 or AMPK signaling suppresses oxidative stress during intestinal inflammation.

AIMS: Oxidative stress and inflammation are always associated. Appropriate management of oxidative mediators may represent a therapeutic strategy to reduce inflammation, and use of antioxidant can be protective against inflammatory diseases. Glycyrrhizin (GL) plays an anti-inflammatory and antioxidant effect by inhibiting high mobility group box 1 (HMGB1) or 11-ß-hydroxysteroid dehydrogenase type II (11ßHSD2) enzyme. In this study, the potential role of dipotassium glycyrrhizate (DPG), a salt of GL, to reduce oxidative stress in intestinal inflammatory condition was investigated in vivo and the mechanism of action of DPG was studied in vitro. RESULTS: In a colitis mouse model DPG affected oxidative stress reducing iNOS and COX-2 expression, as well as NO and PGE2 levels. By means of LPS-stimulated macrophages we found that DPG inhibited the expression of pro-inflammatory cytokines and reduced iNOS and COX-2 expression in a time dependent manner, through two different ways of signal. DPG reduced, at a later time, both iNOS and COX-2, through a mechanism HMGB1-dependent, and at an earlier time only COX-2, through a mechanism AMP-activated kinase (AMPK)-phosphorylation-mediated. CONCLUSION: DPG has a protective effect on colitis and inflammation through the inhibition of oxidative stress. This study clarifies the two-ways mechanism by which DPG inhibits iNOS and COX-2 during inflammation and demonstrates for the first time that AMPK is a target of DPG. Uncovering this mechanism is significant to clarify the relationship between energy homeostasis and anti-oxidative responses and suggests that DPG could play a relevant role in the development of new therapy against inflammatory diseases associated to oxidative stress.

Centrally Delivered BACE1 Inhibitor Activates Microglia, and Reverses Amyloid Pathology and Cognitive Deficit in Aged Tg2576 Mice.

Multiple small-molecule inhibitors of the ß-secretase enzyme (BACE1) are under preclinical or clinical investigation for Alzheimer's disease (AD). Prior work has illustrated robust lowering of central amyloid ß (Aß) after acute administration of BACE1 inhibitors. However, very few studies have assessed the overall impact of chronically administered BACE1 inhibitors on brain amyloid burden, neuropathology, and behavioral function in aged preclinical models. We investigated the effects of a potent nonbrain-penetrant BACE1 inhibitor, delivered directly to the brain using intracerebroventricular infusion in an aged transgenic mouse model. Intracerebroventricular infusion of the BACE1 inhibitor (0.3-23.5 µg/d) for 8 weeks, initiated in 17-month-old Tg2576 mice, produced dose-dependent increases in brain inhibitor concentrations (0.2-13 µm). BACE1 inhibition significantly reversed the behavioral deficit in contextual fear conditioning, and reduced brain Aß levels, plaque burden, and associated pathology (e.g., dystrophic neurites), with maximal effects attained with ∼1 µg/d dose. Strikingly, the BACE1 inhibitor also reversed amyloid pathology below baseline levels (amyloid burden at the start of treatment), without adversely affecting cerebral amyloid angiopathy, microhemorrhages, myelination, or neuromuscular function. Inhibitor-mediated decline in brain amyloid pathology was associated with an increase in microglial ramification. This is the first demonstration of chronically administered BACE1 inhibitor to activate microglia, reverse brain amyloid pathology, and elicit functional improvement in an aged transgenic mouse model. Thus, engagement of novel glial-mediated clearance mechanisms may drive disease-modifying therapeutic benefit with BACE1 inhibition in AD.

Identification and Preclinical Pharmacology of the γ-Secretase Modulator BMS-869780.

Alzheimer's disease is the most prevalent cause of dementia and is associated with accumulation of amyloid-ß peptide (Aß), particularly the 42-amino acid Aß1-42, in the brain. Aß1-42 levels can be decreased by γ-secretase modulators (GSM), which are small molecules that modulate γ-secretase, an enzyme essential for Aß production. BMS-869780 is a potent GSM that decreased Aß1-42 and Aß1-40 and increased Aß1-37 and Aß1-38, without inhibiting overall levels of Aß peptides or other APP processing intermediates. BMS-869780 also did not inhibit Notch processing by γ-secretase and lowered brain Aß1-42 without evidence of Notch-related side effects in rats. Human pharmacokinetic (PK) parameters were predicted through allometric scaling of PK in rat, dog, and monkey and were combined with the rat pharmacodynamic (PD) parameters to predict the relationship between BMS-869780 dose, exposure and Aß1-42 levels in human. Off-target and safety margins were then based on comparisons to the predicted exposure required for robust Aß1-42 lowering. Because of insufficient safety predictions and the relatively high predicted human daily dose of 700 mg, further evaluation of BMS-869780 as a potential clinical candidate was discontinued. Nevertheless, BMS-869780 demonstrates the potential of the GSM approach for robust lowering of brain Aß1-42 without Notch-related side effects.

Role of HMGB1 as a suitable biomarker of subclinical intestinal inflammation and mucosal healing in patients with inflammatory bowel disease.

BACKGROUND: Noninvasive biomarkers of high- and low-grade intestinal inflammation and of mucosal healing (MH) in patients with inflammatory bowel disease are currently lacking. We have recently shown that fecal high mobility group box 1 (HMGB1) protein is a novel biomarker of gut inflammation. We aimed at investigating in a mouse model if HMGB1 was able to foresee both a clinically evident and a subclinical gut inflammation and if its normalization indicated MH. We also aimed at confirming the results in patients with Crohn's disease (CD) and ulcerative colitis. METHODS: C57BL6/J mice were treated with increasing doses of dextran sodium sulphate to induce colitis of different severity degrees; 28 with CD, 23 with ulcerative colitis, and 17 controls were also enrolled. Fecal HMGB1 was analyzed by enzyme-linked immunosorbent assay and immunoblotting. RESULTS: Fecal HMGB1 increased by 5-, 11-, 18-, and 24-folds with dextran sodium sulphate doses of 0.25%, 0.50%, 1%, and 4%, respectively, showing that the protein detected a high-grade and a subclinical inflammation. After a recovery time of 4-week posttreatment, HMGB1 returned to control levels, paralleling MH. In patients, fecal HMGB1 significantly correlated with endoscopic indexes (Simple Endoscopic Score for Crohn's Disease [SES-CD], endoscopic Mayo subscore), but not with the disease activity indexes (Crohn's disease Activity Index, partial Mayo score). CONCLUSIONS: Fecal HMGB1 is a robust noninvasive biomarker of clinically overt and subclinical gut inflammation; it can also be a surrogate marker of MH. We suggest the use of fecal HMGB1 to monitor the disease course and assess therapy outcomes in inflammatory bowel disease.

Mapping histologic patchiness of celiac disease by push enteroscopy.

BACKGROUND: Despite great improvements in serologic testing, duodenal biopsies are still required to diagnose the majority of celiac disease (CD) cases. Nevertheless, the histologic pattern of CD is often patchy, leading to the risk of missing the diagnosis. OBJECTIVE: To evaluate the patchiness of the CD histologic lesions along the small bowel (SB), push enteroscopy has been performed instead of conventional upper GI endoscopy. DESIGN: Prospective, single-center study. SETTING: Tertiary-care referral center. PATIENTS: A total of 41 pediatric patients with suspected CD. INTERVENTION: Prospective evaluation of bulb, duodenal, and jejunal biopsy specimens in the diagnosis of CD. MAIN OUTCOME MEASUREMENTS: Pattern of lesion distribution along the SB (from bulb up to 60 cm beyond the ligament of Treitz) and yield as well accuracy of pediatric CD diagnosis by using push enteroscopy. RESULTS: There was a homogeneous pattern of histologic damage in 17 patients (41.5%), whereas 24 patients (58.5%) had a lesion pattern of patchiness. The second and fourth duodenal regions were involved in 38 children (92.7%) and 37 children (90.2%), respectively; the bulb was involved in 37 patients (90.2%); both distal and proximal jejunal samples showed histologic lesions in 38 children (92.7%). In 1 patient, without lesions in the bulb and duodenum, CD was diagnosed according to proximal and distal jejunal biopsies only (3B and C, respectively). A significant correlation was found between the degree of villous atrophy and the serum anti-transglutaminase titer. LIMITATIONS: Small sample size; academic tertiary-care setting. CONCLUSION: CD histologic lesions often have a discontinuous distribution along the SB, occasionally with an exclusive jejunal involvement. A high degree of villous atrophy correlates with a high anti-transglutaminase titer. When the new ESPGHAN "biopsy-sparing" criteria are not applicable, in case of potential CD, push enteroscopy might be a valuable second-step tool to re-evaluate and identify false "potential" CD hiding exclusive jejunal lesions.

Necroptosis is active in children with inflammatory bowel disease and contributes to heighten intestinal inflammation.

OBJECTIVES: A new caspase-independent mode of programmed cell death, termed necroptosis, has recently been identified. Altered expression of molecules involved in the necroptosis pathway has been shown to trigger intestinal inflammation. The initiation of necroptosis is principally mediated by the release of receptor interacting protein 3 (RIP3) from suppression by caspase-8. Furthermore, it has been suggested that the mixed lineage kinase domain-like (MLKL) factor is an interacting target of RIP3 in active necroptosis. This study aims at investigating the occurrence of necroptosis in children with inflammatory bowel disease (IBD) and its contribution to human intestinal inflammation. METHODS: Biopsy samples were collected from the ileum and colon of 33 children with Crohn's disease, 30 with ulcerative colitis, and 20 healthy controls. Ten children with allergic colitis (AC) were used as non-IBD comparators. RIP3, caspase-8, and MLKL protein expression levels were evaluated by western blotting. The adenocarcinoma cell line HT29 was used for in vitro experiments. RESULTS: RIP3 and MLKL increased (P<0.01) in inflamed tissues of IBD and AC patients, whereas caspase-8 was reduced. No variations were observed in uninflamed tissues of patients. The relationship between RIP3 increase, active necroptosis, and intestinal inflammation was confirmed by in vitro analyses. CONCLUSIONS: We show for the first time that necroptosis is strongly associated with intestinal inflammation in children with IBD and contributes to strengthen the inflammatory process. We believe that RIP3 and MLKL could represent attractive targets for the management of human IBD.

Presenting features and disease course of pediatric ulcerative colitis.

UNLABELLED: Clinical variables and disease course of pediatric ulcerative colitis (UC) have been poorly reported. The aim of this study was to retrospectively describe the phenotype and disease course of pediatric onset UC diagnosed at a tertiary referral Center for Pediatric Gastroenterology. PATIENTS AND METHODS: 110 patients with a diagnosis of UC were identified at our Department database. Records were reviewed for disease location and behavior at the diagnosis, family history for inflammatory bowel disease, pattern changes at the follow-up, need of surgery and cumulative risk for colectomy. RESULTS: Thirty-five % of patients had an early-onset disease (0-7 years). At the diagnosis, 29% had proctitis, 22% left-sided colitis, 15% extensive colitis and 34% pancolitis. Fifteen % presented with a rectal sparing, while a patchy colonic inflammation was reported in 18%. Rectal sparing was significantly related to the younger age (p: <0.05). Disease extension at the follow up was reported in 29% of pts. No clinical variables at the diagnosis were related to the subsequent extension of the disease. The cumulative rates of colectomy were 9% at 2 year and 14% at 5 years. An extensive disease as well as acute severe colitis and corticosteroid therapy at the diagnosis were significantly associated with an increased risk of colectomy. CONCLUSIONS: Pediatric UC is extensive and severe at the diagnosis, with an overall high rate of disease extension at the follow-up. Endoscopic atypical features are common in young children. The colectomy rate is related to the location and severity of the disease at the diagnosis.

Characterization of adherent-invasive Escherichia coli isolated from pediatric patients with inflammatory bowel disease.

BACKGROUND: Crohn's disease (CD) and ulcerative colitis (UC), known as inflammatory bowel diseases (IBD), are characterized by an abnormal immunological response to commensal bacteria colonizing intestinal lumen and mucosa. Among the latter, strains of adherent-invasive Escherichia coli (AIEC), capable of adhering to and invading epithelium, and to replicate in macrophages, have been described in CD adults. We aimed at identifying and characterizing AIEC strains in pediatric IBD. METHODS: In all, 24 CD children, 10 UC, and 23 controls were investigated. Mucosal biopsies, taken during colonoscopy, were analyzed for the presence of AIEC strains by an adhesive-invasive test. Protein expression of the specific AIEC receptor, the carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6), was evaluated by western blot and immunohistochemistry, while tumor necrosis factor alpha (TNF-α) and interleukin (IL)-8 mRNA expression was detected by real-time polymerase chain reaction (PCR), after bacterial infection. Transmission electron microscopy and trans-epithelial electric resistance assays were performed on biopsies to assess bacteria-induced morphological and functional epithelial alterations. RESULTS: Two bacterial strains, EC15 and EC10, were found to adhere and invade the Caco2 cell line, similar to the well-known AIEC strain LF82 (positive control): they upregulated CEACAM6, TNF-α, and IL-8 gene/protein expression, in vitro and in cultured intestinal mucosa; they could also survive inside macrophages and damage the epithelial barrier integrity. Lesions in the inflamed tissues were associated with bacterial infection. CONCLUSIONS: This is the first study showing the presence of adhesive-invasive bacteria strains in the inflamed tissues of children with IBD. Collective features of these strains indicate that they belong to the AIEC spectrum, suggesting their possible role in disease pathogenesis.