Yuichiro Nasu

Liver regeneration after partial hepatectomy in rat is more impaired in a steatotic liver induced by dietary fructose compared to dietary fat.

Hepatic steatosis (HS) has a negative effect on liver regeneration, but different pathophysiologies of HS may lead to different outcomes. Male Sprague-Dawley rats were fed a high fructose (66% fructose; H-fruc), high fat (54% fat; H-fat), or control chow diet for 4 weeks. Based on hepatic triglyceride content and oil red O staining, HS developed in the H-fruc group, but was less severe compared to the H-fat group. Hepatic mRNA expression levels of fatty acid synthase and fructokinase were increased and those of carnitine palmitoyltransferase-1 and peroxisome proliferator-activated receptor-α were decreased in the H-fruc group compared to the H-fat group. Liver regeneration after 70% partial hepatectomy (PHx) was evaluated by measuring the increase in postoperative liver mass and PCNA-positive hepatocytes, and was impaired in the H-fruc group compared to the H-fat and control groups on days 3 and 7. Serum levels of tumor necrosis factor-α, interleukin-6 and hepatocyte growth factor did not change significantly after PHx. In contrast, serum TGF-β1 levels were slightly but significantly lower in the control group on day 1 and in the H-fat group on day 3 compared to the level in each group on day 0, and then gradually increased. However, the serum TGF-β1 level did not change after PHx in the H-fruc group. These results indicate that impairment of liver regeneration after PHx in HS is related to the cause, rather than the degree, of steatosis. This difference may result from altered metabolic gene expression profiles and potential dysregulation of TGF-β1 expression.

Human neutrophil peptides induce interleukin-8 in intestinal epithelial cells through the P2 receptor and ERK1/2 signaling pathways

Human neutrophil peptides (HNPs) are antimicrobial peptides produced predominantly by neutrophils. We have previously reported that HNP 1-3 levels are increased in the sera and plasma of patients with active ulcerative colitis. The increased expression of interleukin-8 (IL-8) has also been demonstrated in the colonic mucosa of patients with active ulcerative colitis. HNPs induce IL-8 in lung epithelial cells and monocytes through the P2Y6 signaling pathway. However, the association between HNPs and IL-8 in the intestinal mucosa has not yet been investigated. In the present study, we investigated the effects of HNP-1 on the production of IL-8 by human intestinal epithelial cells and the underlying signaling mechanisms. We observed a significant increase in IL-8 expression in the human colon carcinoma cell line, Caco-2, following treatment with HNP-1. The non-selective P2 receptor antagonists, suramin and pyridoxal phosphate-6-azo (benzene-2,4-disulfonic acid) tetrasodium salt hydrate (PPADS), significantly blocked the HNP-1-induced expression of IL-8 in the Caco-2 cells. The P2Y6-specific antagonist, MRS2578, led to a significant but partial decrease in IL-8 expression, suggesting that P2 receptors in addition to P2Y6 are involved in the HNP-1-induced production of IL-8 by Caco-2 cells. In agreement with this finding, HNP-1 also significantly increased IL-8 production in the P2Y6-negative human colon cancer cell line, HT-29, and this increase was blocked by treatment with suramin and PPADS. HNP-1 significantly increased the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) in the HT-29 cells. However, the HNP-1-induced production of IL-8 was suppressed by the ERK1/2 inhibitor, U0126, but not by the p38 MAPK inhibitor, SB203580. In conclusion, our data demonstrate that HNP-1 induces IL-8 production not only through P2Y6, but also through additional P2 receptors via an ERK1/2-dependent mechanism in intestinal epithelial cells.

Effect of Endoscopic Submucosal Dissection for Superficial Esophageal Neoplasms and Risk Factors for Postoperative Stricture

AbstractEndoscopic submucosal dissection (ESD) enables wider tumor resection compared with endoscopic mucosal resection and en bloc resection of superficial esophageal neoplasms. However, ESD may cause difficult-to-treat stricture of the esophagus, and therefore, prediction of and measures against postoperative esophageal stricture are critical. The aim of this study was to evaluate the effect of ESD on superficial esophageal neoplasms and identify risk factors associated with esophageal stricture after ESD.This study included 165 lesions in 120 patients with superficial esophageal neoplasms, including cancer and neoplasia, who underwent ESD from 2009 to 2013.The complete resection rate of superficial esophageal neoplasms by ESD was 90.9%. After ESD, 22 subjects (18.3%) had symptomatic esophageal stricture, 12 (10.0%) had aspiration pneumonia of grade 2, and 7 (5.8%) had mediastinal emphysema of grade 2. Comparison of the 22 subjects with stricture with the 98 subjects without stricture showed significant differences in the rate of resection of >75% of the esophageal circumference, rate of whole circumference resection, and the required time for resection. The tumor size and the size of the resected tissue sample also differed between the 2 groups. The groups did not differ in age, sex, alcohol intake, and smoking; location, macroscopic, and histological tumor findings; chest pain; or use of anticoagulants for comorbidities. In multivariate analysis, tumor size and whole circumference resection were independent risk factors for stricture. Furthermore, in 45 subjects with resection of >75% of the esophageal circumference, whole resection of the esophagus was the only independent risk factor for stricture.This study suggests that ESD has a strong therapeutic effect on superficial esophageal neoplasms; however, a greater extent of resection of the esophagus increases the risk of postoperative esophageal stricture. Preventive measures against development of postoperative stricture require further study.

Diagnostic efficacy of liquid-based cytology for solid pancreatic lesion samples obtained with endoscopic ultrasound-guided fine-needle aspiration: Propensity score-matched analysis

There is a paucity of data on the diagnostic efficacy of liquid‐based cytology (LBC) for pancreatic samples obtained by endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA). Using propensity score matching, we retrospectively analyzed the additional diagnostic value of LBC compared to a conventional Papanicolaou smear (CPS) for samples of solid pancreatic lesions obtained by EUS‐FNA.

Fecal Human Neutrophil Peptide Levels Correlate with Intestinal Inflammation in Ulcerative Colitis

Background/Aim: Fecal markers have recently been found to provide convenient and noninvasive assessment of intestinal inflammation in inflammatory bowel disease (IBD). In this study, we examined the clinical significance of fecal human neutrophil peptides (F-HNP) in the evaluation of IBD disease activity. Methods: This study enrolled 70 patients with IBD, consisting of 45 patients with ulcerative colitis (UC), 25 patients with Crohns disease (CD), and 11 non-IBD controls. Stools samples were evaluated for the association between F-HNP concentration and disease and endoscopic activity in each group and the correlation between F-HNP and fecal calprotectin (F-CP) concentrations. Results: Median F-HNP levels were as follows: UC: 25.6 ng/ml; CD: 20.1 ng/ml; and non-IBD controls: 4.9 ng/ml. F-HNP levels were significantly higher in each IBD group, especially in the UC group, than in the control group. In the UC group, both F-HNP and F-CP levels were significantly higher during active disease compared to the remission phase. Both markers were significantly correlated with the Mayo endoscopic score, although the correlation was stronger for F-HNP than for F-CP (r = 0.66 vs. r = 0.54). Conclusion: F-HNP is a noninvasive marker that is useful for evaluating UC endoscopic activity.

Hepatocyte Growth Factor Facilitates Esophageal Mucosal Repair and Inhibits the Submucosal Fibrosis in a Rat Model of Esophageal Ulcer

Background/Aims: Esophageal mucosal damage often causes scar tissue, leading to refractory stricture. The aim of this study was to clarify the effect of hepatocyte growth factor (HGF) on esophageal mucosal repair and fibrosis leading to stricture in a rat model of esophageal ulcer. Methods: Esophageal ulcers were induced in rats by topical exposure of the lower esophageal serosa to acetic acid, followed by intraperitoneal administration of HGF (200 µg/day) using an osmotic pump for 7 days. The effect of HGF on esophageal mucosal injury was investigated macroscopically and microscopically. The effect of HGF on epithelial cell proliferation and the expression of genes closely associated with the development of fibrosis were also examined. Results: The administration of HGF for 7 days led to a significant reduction in the ulcerative area and enhanced the proliferation of esophageal epithelial cells. HGF treatment significantly decreased the fibrosis, and subsequently attenuated not only the foreshortening but also the narrowing of the esophagus. The expression levels of tissue inhibitor of metalloproteinase (TIMP)-1, -2, and matrix metalloproteinase (MMP)-2, -9 were significantly decreased among rats treated with HGF. Conclusion: HGF facilitates the repair of esophageal mucosal injury and may also ameliorate the esophageal fibrosis, possibly through enhanced re-epithelization.

Low concentrations of human neutrophil peptide ameliorate experimental murine colitis

Human neutrophil peptides (HNPs) not only have antimicrobial properties, but also exert multiple immunomodulatory effects depending on the concentration used. We have previously demonstrated that the intraperitoneal administration of high-dose HNP-1 (100 µg/day) aggravates murine dextran sulfate sodium (DSS)-induced colitis, suggesting a potential pro-inflammatory role for HNPs at high concentrations. However, the role of low physiological concentrations of HNPs in the intestinal tract remains largely unknown. The aim of this study was to examine the effects of low concentrations of HNPs on intestinal inflammation. We first examined the effects of the mild transgenic overexpression of HNP-1 in DSS-induced colitis. HNP-1 transgenic mice have plasma HNP-1 levels similar to the physiological concentrations in human plasma. Compared to wild-type mice treated with DSS, HNP-1 transgenic mice treated with DSS had significantly lower clinical and histological scores, and lower colonic mRNA levels of pro-inflammatory cytokines, including interleukin (IL)-1β and tumor necrosis factor (TNF)-α. We then injected low-dose HNP-1 (5 µg/day) or phosphate-buffered saline (PBS) intraperitoneally into C57BL/6N and BALB/c mice administered DSS. The HNP-1-treated mice exhibited significantly milder colitis with reduced expression levels of pro-inflammatory cytokines compared with the PBS-treated mice. Finally, we examined the in vitro effects of HNP-1 on the expression of cytokines associated with macrophage activation. Low physiological concentrations of HNP-1 did not significantly affect the expression levels of IL-1β, TNF-α, IL-6 or IL-10 in colonic lamina propria mononuclear cells activated with heat-killed Escherichia coli, suggesting that the anti-inflammatory effects of HNP-1 on murine colitis may not be exerted by direct action on intestinal macrophages. Collectively, our data demonstrated a biphasic dose-dependent effect of HNP-1 on DSS-induced colitis: an amelioration at low concentrations and an aggravation at high concentrations. Low concentrations of HNPs may contribute to the maintenance of intestinal homeostasis.

T1777 Hepatocyte Growth Factor Stimulates the Migration of Gastric Epithelial Cells by Altering the Intracellular Localization of the Tight Junction Protein ZO-1

Background Hepatocyte growth factor (HGF) is essential for epithelial restitution, a process in which epithelial cells rapidly migrate to cover desquamated epithelium after mucosal injury in the gastrointestinal tract. In this study, we aimed to elucidate the molecular mechanisms of the HGF-mediated reconstitution of gastric epithelial structures by analyzing the expression and subcellular dynamics of tight junction proteins.

S1697 Human Neutrophil Peptide-1 Has Cytotoxic Effects On Colon Cancer Cells and Aggravates Dextran Sulfate Sodium-Induced Colitis

IFN-γ plays an important role in the generation and perpetuation of mucosal inflammation in IBD. TL1A, a TNF superfamily member, synergizes with IL-12 and IL-18 to augment IFN-γ production in human T cells. Enhanced TL1A expression is detected in IBD with a strong TL1A SNP association reported in Crohns disease. We have previously shown TL1A expression is induced in peripheral monocytes and in-vitro derived dendritic cells (DC). The molecular mechanisms regulating TL1A expression during DC differentiation however, remain poorly defined. The human monocytic cell line, KG-1, provides a valuable model for dendritic cell differentiation. The round non-adherent KG1 cells develop a DC-like phenotype following activation by PMA/ionomycin. These cells become loosely adherent with long cytoplasmic projections. A concomitant induction of membrane TL1A and mRNA is observed with mRNA expression being detectable within 2 hours and peaking at 8 hours following stimulation. A strikingly similar kinetics of TL1A expression was likewise noted following PMA/ionomycin stimulation of peripheral monocytes. Further DC maturation of KG-1 cells following treatment with LPS results in additional enhancement of TL1A expression. Transient transfection of KG-1 with TL1A promoter-constructs up to 1.5 kb in length reveals up to 90-fold enhanced expression compared to cells transfected with the promoterless vector. EMSA analysis demonstrates PMA/ionomycin mediated upregulation of nucleo-protein binding to a putative TL1A NFκB binding site. Binding is competed by excess unlabeled wt TL1A NFκB, but not mutant oligonucleotide and is likewise attenuated following proteasomal inhibition by MG132. Our data suggests in the human monocytic KG-1 cell line, differentiation of immature cells towards a mature DC phenotype is associated with functional upregulation of surface TL1A expression and binding of NFκB to the TL1A promoter. These studies provide a molecular basis for future studies which may help elucidate the mechanism modulating TL1A expression during DC maturation.