Chitinase 3-like 1 deficiency ameliorates liver fibrosis by promoting hepatic macrophage apoptosis.

AIM: Chitinase 3-like 1 (CHI3L1), an 18-glycosyl hydrolase-related molecule, is a member of the enzymatically inactive chitinase-like protein family. Serum levels of CHI3L1 are strongly correlated with hepatic fibrosis progression during many liver diseases. Therefore, this protein could be involved in the development of hepatic fibrosis pathology; however, its role has not been elucidated. We aimed to elucidate its role in the pathophysiology of liver fibrosis. METHODS: Chitinase 3-like 1-deficient (Chi3l1-/- ) mice were given carbon tetrachloride twice per week for 4 weeks or fed a methionine choline-deficient diet for 12 weeks to generate mouse liver fibrosis models. Human fibrotic liver tissues were also examined immunohistochemically. RESULTS: In human and mouse fibrotic livers, CHI3L1 expression was mainly localized to hepatic macrophages, and the intrahepatic accumulation of CHI3L1+ macrophages was significantly enhanced compared to that in control livers. In the two mouse models, hepatic fibrosis was significantly ameliorated in Chi3l1-/- mice compared to that in wild-type mice, which was dependent on hepatic macrophages. The accumulation and activation of hepatic macrophages was also significantly suppressed in Chi3l1-/- mice compared to that in wild-type mice. Furthermore, apoptotic hepatic macrophages were significantly increased in Chi3l1-/- mice. Chitinase 3-like 1 was found to inhibit hepatic macrophage apoptosis by suppressing Fas expression and activating Akt signaling in an autocrine manner, which resulted in hepatic macrophage accumulation and activation, exaggerating liver fibrosis. CONCLUSIONS: Chitinase 3-like 1 exacerbates liver fibrosis progression by suppressing apoptosis in hepatic macrophages. Therefore, this might be a potential therapeutic target for the treatment of liver fibrosis.

Platelet interaction with lymphatics aggravates intestinal inflammation by suppressing lymphangiogenesis.

Lymphatic failure is a histopathological feature of inflammatory bowel disease (IBD). Recent studies show that interaction between platelets and podoplanin on lymphatic endothelial cells (LECs) suppresses lymphangiogenesis. We aimed to investigate the role of platelets in the inflammatory process of colitis, which is likely to be through modulation of lymphangiogenesis. Lymphangiogenesis in colonic mucosal specimens from patients with IBD was investigated by studying mRNA expression of lymphangiogenic factors and histologically by examining lymphatic vessel (LV) densities. Involvement of lymphangiogenesis in intestinal inflammation was studied by administering VEGF-receptor 3 (VEGF-R3) inhibitors to the mouse model of colitis using dextran sulfate sodium and evaluating platelet migration to LVs. The inhibitory effect of platelets on lymphangiogenesis was investigated in vivo by administering antiplatelet antibody to the colitis mouse model and in vitro by coculturing platelets with lymphatic endothelial cells. Although mRNA expressions of lymphangiogenic factors such as VEGF-R3 and podoplanin were significantly increased in the inflamed mucosa of patients with IBD compared with those with quiescent mucosa, there was no difference in LV density between them. In the colitis model, VEGF-R3 inhibition resulted in aggravated colitis, decreased lymphatic density, and increased platelet migration to LVs. Administration of an antiplatelet antibody increased LV densities and significantly ameliorated colitis. Coculture with platelets inhibited proliferation of LECs in vitro. Our data suggest that despite elevated lymphangiogenic factors during colonic inflammation, platelet migration to LVs resulted in suppressed lymphangiogenesis, leading to aggravation of colitis by blocking the clearance of inflammatory cells. Modulating the interaction between platelets and LVs could be a new therapeutic means for treating IBD.

Phlebosclerotic colitis that was difficult to distinguish from collagenous colitis.

Phlebosclerotic colitis is a rare and recently known disease entity and its etiology is still to be elucidated. Some phlebosclerotic colitis cases are difficult to distinguish from collagenous colitis because of the similarity of pathological findings. In all Japanese case reports of phlebosclerotic colitis in which an association with the use of Chinese herbal medicine is suspected, sansisi (gardenia fruit) was included, suggesting pathogenesis of this disease. We report a case of phlebosclerotic colitis that wasdifficult to be distinguished from collagenous colitis, and an association with the use of Chinese herbal medicine was suspected as the cause of the disease.

Involvement of autotaxin/lysophospholipase D expression in intestinal vessels in aggravation of intestinal damage through lymphocyte migration.

Lysophosphatidic acid (LPA) has a critical role in lymphocyte migration to secondary lymphoid organs. Autotaxin (ATX)/lysophospholipase D, in the vascular endothelium, is the main enzyme involved in LPA production. Whether ATX is involved in pathological lymphocyte migration to the inflamed mucosa has not been studied. We investigated the involvement of ATX in inflammatory bowel disease patients and two murine models of colitis. Tissue samples were obtained by intestinal biopsies from patients with Crohn's disease and those with ulcerative colitis with informed consent. ATX immunoreactivity was colocalized with MAdCAM-1-positive high-endothelial-like vessels, close to sites of lymphocyte infiltration. Enhanced expression of ATX mRNA was observed in the inflamed mucosa from Crohn's disease and ulcerative colitis patients. ATX mRNA expression level was remarkably higher in the actively inflamed mucosa than in the quiescent mucosa in the same patient. In the T-cell-transferred mouse model, ATX mRNA expression level gradually increased as colitis developed. In the dextran sodium sulfate mouse model, the expression level was considerably higher in colonic mucosa of chronically developed colitis than in colonic mucosa of acute colitis. Administration of an ATX inhibitor, bithionol, remarkably decreased lymphocyte migration to the intestine and ameliorated both dextran sodium sulfate-induced colitis and CD4-induced ileocolitis. In transwell assays, administration of bithionol or 1-bromo-3(s)-hydroxy-4-(palmitoyloxy) butylphosphonate (BrP-LPA) significantly decreased transmigration of splenocytes through high-endothelial-like vessels induced by TNF-α. We conclude that enhanced expression of ATX in the active mucosa has been implicated in the pathophysiology of inflammatory bowel disease through enhancing aberrant lymphocyte migration to the inflamed mucosa.

Dietary lipids and sweeteners regulate glucagon-like peptide-2 secretion.

Glucagon-like peptide-2 (GLP-2) is a potent intestinal growth factor derived from enteroendocrine L cells. Although food intake is known to increase GLP-2 secretion, its regulatory mechanisms are largely unknown as a result of its very short half-life in venules. The aims of this study were to compare the effects of luminal nutrients on the stimulation of GLP-2 secretion in vivo using lymph samples and to clarify the involvement of the sweet taste receptor in this process in vitro. Lymph samples were collected from the thoracic duct after bolus administration of dietary lipids or sweetening agents into the duodenum of rats. Human enteroendocrine NCI-H716 cells were also used to compare the effects of various nutrients on GLP-2 secretion. GLP-2 concentrations were measured by ELISA in vivo and in vitro. GLP-2 secretion was enhanced by polyunsaturated fatty acid- and monounsaturated fatty acid-rich dietary oils, dietary carbohydrates, and some kinds of sweeteners in rats; this effect was reproduced in NCI-H716 cells using α-linolenic acid (αLA), glucose, and sweeteners. GLP-2 secretion induced by sweetening agents was inhibited by lactisole, a sweetness-antagonizing inhibitor of T1R3. In contrast, lactisole was unable to inhibit GLP-2 secretion induced by αLA alone. Our results suggested that fatty acid- and sweetener-induced GLP-2 secretion may be mediated by two different pathways, with the sweet taste receptor involved in the regulation of the latter.

Endoscopic finding of spontaneous hemorrhage correlates with tumor necrosis factor alpha expression in colonic mucosa of patients with ulcerative colitis.

BACKGROUND: Ulcerative colitis (UC) is an intractable colonic disease, and it shows several endoscopic findings. Recently, it was reported that the expression level of mucosal tumor necrosis factor alpha (TNF-α) was useful for predicting patient response to infliximab. However, no data regarding the value of endoscopic findings to predict treatment efficacy or cytokine expression level exist. OBJECTIVE: We investigated the expression of leukocyte adhesion-related molecules and cytokines in colonic mucosa and compared it to endoscopic findings. METHODS: One hundred and fifty-nine patients were enrolled. Tissue samples were obtained by colonic biopsy from patients with UC. Colitis activity was determined by Matts' criteria. The degree of mRNA expression of TNF-α, interferon gamma (IFN-γ), interleukin (IL)-8, IL-17A, and mucosal vascular addressin adhesion molecule-1 (MAdCAM-1) in mucosal samples was determined by real-time quantitative polymerase chain reaction. These expression levels were compared with the degree of Matts' grade and individual endoscopic findings. RESULTS: The expression of TNF-α, IFN-γ, IL-8, IL-17A, and MAdCAM-1 mRNA significantly increased as Matts' endoscopic grade elevated. Actively inflamed mucosa with spontaneous hemorrhage revealed a significantly increased expression level of TNF-α mRNA than that without spontaneous hemorrhage. No other individual endoscopic parameter was significantly correlated with the expression level of TNF-α mRNA. CONCLUSIONS: Inflamed mucosa with spontaneous hemorrhage may suggest increased expression of TNF-α mRNA levels in colonic mucosa of UC patients, which could predict a lower response to infliximab treatment and more aggressive induction regime or change to other therapy should be taken into account.

Trans fatty acids in diets act as a precipitating factor for gut inflammation?

Fatty acids in our daily diet are broadly classified into cis and trans fatty acids (TFAs). TFAs are formed during the manufacturing process of hydrogenated vegetable oils such as margarine. Modern diets such as deep-fried products, frozen foods, and packaged snacks commonly include large quantities of margarine containing TFAs. Although an increased report in the effects of the diet containing TFAs on a risk factor of metabolic syndrome, diabetes mellitus, and coronary heart disease has been observed in the recent years, influence on intestinal inflammation remains unknown. This review describes pro-inflammatory effects of TFAs in our diary diet on various systemic disorders and also discusses a possible role of TFAs on gut inflammation.

Physiological stress exacerbates murine colitis by enhancing proinflammatory cytokine expression that is dependent on IL-18.

Psychological stress is an environmental factor considered to be a precipitating factor of inflammatory bowel disease. Interleukin (IL)-18 plays a role in stress-induced aggravation in some diseases. The aim of this study was to establish a model of murine colitis exacerbated by psychological stress and to clarify the role of IL-18 in this model. Male C57Bl/6 mice and IL-18(-/-) mice were used for this study. The mice received dextran sulfate sodium (DSS) for induction of colitis. Some mice were exposed to psychological stress using a communication box. Body weight, colonic length, and histological inflammation were measured for assessment of colitis. Tumor necrosis factor (TNF)-α and IL-18 expression in the colon and IL-18 expression in the adrenal gland were analyzed using real-time PCR. The effect of anti-IL-18 antibody was also investigated. Effects of TNF-α and IL-18 on cytokine expressions were studied using the colonic epithelial cell line LS174T. Induction of psychological stress in DSS-treated wild-type mice significantly exacerbated colitis with enhanced expression of proinflammatory cytokines and IL-18. However, induction of psychological stress in DSS-treated IL-18(-/-) mice did not aggravate colitis compared with that in the IL-18(-/-) group given only DSS treatment. Stress-induced aggravation of colitis was ameliorated significantly by anti-IL-18 antibody treatment. IL-18 did not enhance TNF-α-induced expression of intercellular adhesion molecule-1 or IL-8 in LS174T. We established a model of colitis exacerbated by psychological stress. Psychological stress enhanced IL-18 expression and plays a proinflammatory role in stress-induced aggravation of colitis.

A case of intraductal papillary mucinous neoplasm of the pancreas rupturing both the stomach and duodenum.

BACKGROUND: Intraductal papillary mucinous neoplasm (IPMN) of the pancreas may extend to other organs. However, it is rare for a histopathologically benign IPMN to rupture other organs, particularly multiple organs. There has been no report of a benign IPMN rupturing both the stomach and duodenum. OBJECTIVE: We experienced a very rare case and make personal remarks based on bibliographical consideration. DESIGN: Case report. SETTING: National Defense Medical College. PATIENT: A patient with IPMN. INTERVENTION: EGD, ERCP, and pancreatoduodenectomy. CONCLUSIONS: We report a case of benign IPMN of the pancreas extending to two adjacent organs. A 77-year-old male who was diagnosed as having IPMN by CT, MRI, upper GIF, and ERCP underwent pancreatoduodenectomy for a mass of 4.2 cm in diameter. Pathological examinations revealed that the IPMN was composed of adenoma. Intraluminal nodular growth was observed in the duodenal gland tissue, and abnormal growth was observed in the fistula to the stomach. According to a literature review based on PubMed data up until March 2009, it is rare for a benign IPMN to penetrate two adjacent organs.

Lipoprotein Lipase Up-regulation in Hepatic Stellate Cells Exacerbates Liver Fibrosis in Nonalcoholic Steatohepatitis in Mice.

Lipoprotein lipase (LPL) plays a central role in incorporating plasma lipids into tissues and regulates lipid metabolism and energy balance in the human body. Conversely, LPL expression is almost absent in normal adult livers. Therefore, its physiological role in the liver remains unknown. We aimed to elucidate the role of LPL in the pathophysiology of nonalcoholic steatohepatitis (NASH), a hepatic manifestation of obesity. Hepatic stellate cell (HSC)-specific LPL-knockout (LplHSC-KO ) mice, LPL-floxed (Lplfl/fl ) mice, or double-mutant toll-like receptor 4-deficient (Tlr4-/- ) LplHSC-KO mice were fed a high-fat/high-cholesterol diet for 4 weeks to establish the nonalcoholic fatty liver model or an high-fat/high-cholesterol diet for 24 weeks to establish the NASH model. Human samples, derived from patients with nonalcoholic fatty liver disease, were also examined. In human and mouse NASH livers, serum obesity-related factors, such as free fatty acid, leptin, and interleukin-6, dramatically increased the expression of LPL, specifically in HSCs through signal transducer and activator of transcription 3 signaling, as opposed to that in hepatocytes or hepatic macrophages. In the NASH mouse model, liver fibrosis was significantly reduced in LplHSC-KO mice compared with that in Lplfl/fl mice. Nonenzymatic LPL-mediated cholesterol uptake from serum lipoproteins enhanced the accumulation of free cholesterol in HSCs, which amplified TLR4 signaling, resulting in the activation of HSCs and progression of hepatic fibrosis in NASH. Conclusion: The present study reveals the pathophysiological role of LPL in the liver, and furthermore, clarifies the pathophysiology in which obesity, as a background factor, exacerbates NASH. The LPL-mediated HSC activation pathway could be a promising therapeutic target for treating liver fibrosis in NASH.

Nicotine treatment ameliorates DSS-induced colitis by suppressing MAdCAM-1 expression and leukocyte recruitment.

The enhanced recruitment of leukocytes to the inflamed colon is a key feature of ulcerative colitis (UC). The gut-specific adhesion molecules involved in leukocyte recruitment have emerged as recent therapeutic targets. Nicotine absorbed from smoking has been reported to work protectively in UC patients. Our hypothesis is that nicotine may suppress the aberrant leukocyte recruitment and colonic inflammation via the suppression of the overexpressed gut-specific adhesion molecules in the inflamed colon. To test this hypothesis, the severity of colitis and the degree of leukocyte recruitment induced by gut-specific adhesion molecules were assessed in dextran sulfate sodium (DSS) colitis mice (C57BL/6J mice treated with 3% DSS) with or without nicotine treatment. We also studied the in vitro changes in the expression of adhesion molecules by using a vascular endothelial cell line. DSS-induced colitis was accompanied by increases in disease activity index (DAI), histological score, recruitment of leukocytes, and the expression of adhesion molecules, mucosal vascular addressin cell adhesion molecule-1 (MAdCAM-1) and VCAM-1. Nicotine treatment significantly attenuated MAdCAM-1 expression, leukocyte recruitment, DAI, and histological score. The expression of ß7-integrin, the ligand for MAdCAM-1, on leukocytes was not affected by nicotine treatment. In vitro study, the TNF-α-enhanced mRNA expression of MAdCAM-1 was reduced by the coadministration of nicotine in a dose-dependent manner, possibly via nicotinic receptor activation. These results supported our hypothesis that nicotine treatment ameliorated colitis through the suppression of MAdCAM-1 expression on the microvessels in the inflamed colon. Further investigation is warranted on the role of nicotine in the treatment of UC.

Aromatherapies using Osmanthus fragrans oil and grapefruit oil are effective complementary treatments for anxious patients undergoing colonoscopy: A randomized controlled study.

BACKGROUND AND AIMS: Colonoscopy can be painful and uncomfortable. Aromatherapy is often used for the relief of anxiety or discomfort. Recently, it has been reported that olfactory stimulation induces various physiological effects. We investigated the effects of aromatherapy on anxiety and abdominal discomfort during colonoscopy. METHODS: The investigation was carried out using a randomized controlled study. Aromatherapy was performed by vapor diffusion, and each patient was given one of the following treatments: no inhalation (control group), essential-oil-less vapor (vehicle group), lavender oil (lavender group), grapefruit oil (grapefruit group), or Osmanthus fragrans oil (Osmanthus fragrans group). Following total colonoscopy procedures, each patient estimated their anxiety and abdominal discomfort using the Numeric Rating Scale. RESULTS: Total colonoscopy was performed on 361 patients. No complications caused by colonoscopy or aromatherapy were experienced. In the Osmanthus fragrans group, anxiety was significantly attenuated. The abdominal discomfort of patients who reported strong anxiety during colonoscopy was significantly attenuated in the grapefruit group and the Osmanthus fragrans group. CONCLUSION: Aromatherapies using Osmanthus fragrans oil and grapefruit oil are effective complementary treatments for anxious patients undergoing colonoscopy.

IL-6 Mediates the Intestinal Microvascular Thrombosis Associated with Experimental Colitis.

Inflammatory bowel diseases are associated with increased risk for thrombus formation both within the inflamed bowel and at distant sites. Although the increased propensity for distant organ thrombus development has been recapitulated in animal models of colitis and linked to interleukin-6 (IL-6), it remains unclear whether experimental colitis results in accelerated thrombus development within the inflamed bowel and whether IL-6 contributes to a local thrombogenic response. These issues related to thrombus formation within the inflamed bowel were addressed in mice with dextran sodium sulfate-induced colitis. Wild-type (WT) mice, IL-6 deficient (IL-6(-/-)) mice, and bone marrow chimeras (WT→WT and IL-6(-/-)→WT) were used. The effects of treatment with either an IL-6-blocking, IL-6Rα-blocking or gp130-blocking antibody were also evaluated. Disease activity index and colonic weight-to-length ratio (W/L) were used to monitor the development of colitis. Intravital videomicroscopy was used to study thrombus development (induced with the light/dye method) in mucosal vessels of the ascending colon. Thrombus development was significantly enhanced in WT colitic mice. Neither genetic deficiency nor immunoblockade of IL-6 significantly altered the disease activity index and W/L responses to dextran sodium sulfate treatment. However, colitis-induced thrombogenesis was attenuated in IL-6(-/-) mice and in WT mice treated with either the IL-6-blocking, IL-6Rα-blocking or gp130-blocking antibody. IL-6(-/-)→WT, but not WT→WT chimeras, exhibited a blunted thrombosis response to dextran sodium sulfate. These results indicate that experimental colitis is associated with accelerated thrombus development within the inflamed colon and that IL-6, derived from bone marrow-derived blood cells, is largely responsible for this response.

Prevalence of serum celiac antibody in patients with IBD in Japan.

BACKGROUND: Although the incidence of inflammatory bowel diseases (IBD) in Japan has increased, the prevalence of celiac disease is considered very low with the lowest genetic disposition. IBD is reported as the most common comorbidity because of the high positive rate of serological celiac markers. The aim of this study was to examine the current incidence of celiac disease, especially in IBD patients in Japan, where both wheat consumption and incidence of IBD have increased. METHODS: A total of 172 patients with IBD and 190 controls in Japan were screened for serum antibody of tissue transglutaminase and deaminated gliadin peptide. In sero-positive patients, HLA testing and upper gastrointestinal endoscopy with duodenal biopsy was performed. Some of the sero-positive patients started a gluten-restricted or unrestricted diet, and serological change was determined. RESULTS: The positivity of both serum antibodies was significantly higher in IBD and correlated with disease activity. However, no biopsy-defined or HLA-defined true celiac disease was found. A decrease in serum antibody titers was observed with a gluten-restricted diet. CONCLUSIONS: Despite the increased incidence of IBD and high positivity for serum celiac antibody in Japanese IBD patients, no true-positive celiac disease was noted, suggesting the presence of gluten intolerance in these populations.

1,4-Dihydroxy-2-naphthoic acid from Propionibacterium freudenreichii reduces inflammation in interleukin-10-deficient mice with colitis by suppressing macrophage-derived proinflammatory cytokines.

The anti-inflammatory mechanism of prebiotics has recently been shown to have an impact on the host immune system. DHNA from Propionibacterium freudenreichii is known to promote the proliferation of Bifidobacterium and can ameliorate colitis, although its mode of action remains unknown. In this study, we investigated whether DHNA attenuates inflammation in piroxicam-treated IL-10(-/-) mice, particularly focusing on the changes of the host immune mechanism. DHNA was administered to IL-10(-/-) mice with colitis, and the expression of adhesion molecules and mRNA levels of proinflammatory cytokines were determined. DHNA pretreatment attenuated the piroxicam-induced histological changes. The increased F4/80-positive cell infiltration and VCAM-1 expression were decreased by DHNA administration. The increased mRNA levels of proinflammatory cytokines were also suppressed by DHNA. In in vitro experiments, increased mRNA levels of proinflammatory cytokines after endotoxin exposure were decreased significantly by DHNA pretreatment in RAW264.7, a macrophage cell line, and IL-10(-/-) mice BMMs, whereas the expression of VCAM-1 in bEnd.3 cells, a endothelial cell line, was not affected. Taken together, these findings suggest that administration of DHNA is useful for the treatment of colitis in piroxicam-treated IL-10(-/-) mice and that attenuation of colitis by DHNA may partly be a result of its direct action on intestinal macrophages to inhibit proinflammatory cytokine production.

HIF-1 in T cells ameliorated dextran sodium sulfate-induced murine colitis.

HIF-1 is active in hypoxia, such as inflamed mucosa, and HIF-1 in epithelium has been reported to control inflamed mucosa in IBD models. Although T cells play an important role for pathogenesis of IBD, the function of HIF-1 in T cells remains to be elucidated. We aimed to clarify the function of HIF-1 in T cells in IBD with focus on the balance between Treg and Teff. Double immunohistochemistry of colonic mucosa in IBD patients showed that HIF-1 was expressed in T cells infiltrating the inflamed mucosa, suggesting that HIF-1 in T cells is involved in the pathogenesis. DSS administration to T cell-specific HIF-1α KO mice showed more severe colonic inflammation than control mice with the up-regulation of Th1 and Th17. Hypoxic stimulation in vitro increased Treg activation in WT T cells but not in HIF-1-deleted T cells. In contrast, hypoxic stimulation increased Th17 activation, and the degree was higher in HIF-1-deleted cells than in control cells. These results show that hypoxia controls intestinal inflammation by regulating cytokine balance in a HIF-1-dependent manner, suggesting that strengthening HIF-1 induction in T cells at the sites of inflammation might be a therapeutic strategy for IBD regulation.