Multiple gut-liver axis abnormalities in children with obesity with and without hepatic involvement.

BACKGROUND: Gut-liver axis (GLA) dysfunction appears to play a role in obesity and obesity-related hepatic complications. OBJECTIVES: This study sought to concurrently explore several GLA components in a paediatric obese population with/without liver disease. METHODS: Thirty-two children (mean age 11.2 years) were enrolled: nine controls with normal weight and 23 patients with obesity (OB+). Of the 23 patients OB(+), 12 had not steatosis (ST-), and 11 had steatosis (ST+) (associated [n = 8] or not [n = 3] with hypertransaminasaemia [ALT +/-]). Subjects were characterized by using auxologic, ultrasonographic and laboratory parameters. A glucose hydrogen breath test was performed to test for small intestinal bacterial overgrowth, a urinary lactulose/mannitol ratio (LMR) was obtained to assess intestinal permeability, and tests for transaminases, blood endogenous ethanol, endotoxin and faecal calprotectin were also conducted. RESULTS: Eleven out of 23 patients OB(+) (p < 0.05) exhibited pathological (>90th percentile of the control group values) LMR, with values paralleling the grade of liver involvement (normal weight < OB[+] < OB[+]ST[+]ALT[-] < OB[+)]ST[+]ALT[+] [p < 0.05]). LMR significantly correlated with ethanolaemia (r = 0.38, p = 0.05) and endotoxaemia (r = 0.48, p = 0.015) concentrations. Increased permeability was a risk factor for the development of steatosis (p < 0.002). SIBO was present only in patients with obesity. Faecal calprotectin concentrations were within normal limits in all subjects. CONCLUSIONS: Increased permeability, endogenous ethanol and systemic endotoxin concentrations reflect some GLA dysfunction in obesity and its hepatic complications. Pending further results to establish their potential causative roles, the modulation of the GLA appears to represent a possible target for the prevention and treatment of these conditions.

Acute organ failure following the loss of anti-apoptotic cellular FLICE-inhibitory protein involves activation of innate immune receptors.

Apoptosis signaling is involved in both physiological tissue homeostasis and acute and chronic diseases. The role of regulatory apoptosis signaling molecules and their organ-specific functions are less defined. Therefore, we investigated the loss of the anti-apoptotic cellular FLICE-inhibitory protein (cFLIP) and the mechanisms of the resulting lethal organ failure in vivo using inducible knockout mice. These were generated by crossing floxed cFLIP mice to a tamoxifen inducible Rosa26-creERT2 mouse strain. Death following global loss of cFLIP resulted from liver failure, accumulation of M1-polarized macrophages and accompanying hepatic cell death and inflammation. Apoptosis was also prominent in immune cells, the kidney and intestinal epithelial cells (IECs) but not in cardiomyocytes. Cellular injury led to the release of damage-associated molecular patterns (DAMPs) and the induction of innate immune receptors including toll-like receptors (TLRs) 4 and 9, and stimulator of interferon genes (STING). Transplantation of bone marrow with intact cFLIP or depletion of macrophages prevented the phenotype of acute liver failure. Interestingly, compound deletion of cFLIP in bone marrow-derived cells and hepatocytes did not promote organ failure. Thus, cFLIP exerts a critical role in tissue homeostasis by preventing the activation of monocytic cells and innate immunity, which causes cell death and inflammation in susceptible tissues. These results encourage the development of organ-specific anti-apoptotic and anti-inflammatory therapies in acute organ failure.

Cinnamon extract inhibits degranulation and de novo synthesis of inflammatory mediators in mast cells.

BACKGROUND: Mast cells (MC) are main effector cells of allergic and other inflammatory reactions; however, only a few anti-MC agents are available for therapy. It has been reported that cinnamon extract (CE) attenuates allergic symptoms by affecting immune cells; however, its influence on MC was not studied so far. Here, we analyzed the effects of CE on human and rodent MC in vitro and in vivo. METHODS: Expression of MC-specific proteases was examined in vivo in duodenum of mice following oral administration of CE. Release of mediators and phosphorylation of signaling molecules were analyzed in vitro in human MC isolated from intestinal tissue (hiMC) or RBL-2H3 cells challenged with CE prior to stimulation by FcεRI cross-linking. RESULTS: Following oral treatment with CE, expression of the mast cell proteases MCP6 and MC-CPA was significantly decreased in mice. In hiMC, CE also caused a reduced expression of tryptase. Moreover, in hiMC stimulated by IgE cross-linking, the release of ß-hexosaminidase was reduced to about 20% by CE. The de novo synthesis of cysteinyl leukotrienes, TNFα, CXCL8, CCL2, CCL3, and CCL4, was almost completely inhibited by CE. The attenuation of mast cell mediators by CE seems to be related to particular signaling pathways, because we found that activation of the MAP kinases ERK, JNK, and p38 as well as of Akt was strongly reduced by CE. CONCLUSION: CE decreases expression of mast cell-specific mediators in vitro and in vivo and thus is a new plant-originated candidate for anti-allergic therapy.

Enhancement of intestinal inflammation in mice lacking interleukin 10 by deletion of the serotonin reuptake transporter.

BACKGROUND: Enterochromaffin cells and enteric neurons synthesize and release serotonin (5-HT). Reuptake, mediated by a plasmalemmal transporter (SERT) terminates the action of released 5-HT. Serotonin secretion and serotonin reuptake transporter (SERT) expression have been reported to be decreased in TNBS-induced experimental colitis and in patients with ulcerative colitis. The present study was designed to utilize the transgenic deletion of SERT as a gain-of-function model to test the hypothesis that 5-HT is a pro-inflammatory mediator in experimental colitis. METHODS: Colitis was compared in animals with IL10(+/+)SERT(+/+) (wild-type), IL10(-/-)SERT(+/+), IL10(-/-)SERT(+/-), and IL10(-/-)/SERT(-/-) (double knockout) genotypes. Macroscopic and histological damage scores were evaluated after a time period of up to 15 weeks. KEY RESULTS: Serotonin reuptake transporter expression was significantly increased in the inflamed colons of IL-10(-/-) mice, which displayed intestinal damage and a minor decrement in general health. General health was significantly worse and intestinal inflammation was more severe in IL-10(-/-)SERT(+/-), and IL-10(-/-)SERT(-/-) mice than in IL-10(-/-)SERT(+/+) or wild-type animals. Regardless of the associated SERT genotype, the number of 5-HT-immunoreactive cells was decreased by approximately 55-65% in all mice lacking IL-10. CONCLUSIONS & INFERENCES: Our observations indicate that colitis associated with IL-10 deficient mice is enhanced when the IL-10 deficiency is combined with a SERT deficiency. The data support the concept that 5-HT is a pro-inflammatory mediator in the gut.

Treatment with the 5-HT3 antagonist tropisetron modulates glucose-induced obesity in mice.

OBJECTIVE: Sugar consumption has increased markedly over the last few decades and parallels the dramatic increase in overweight and obesity. Data obtained from animal studies suggest that the intestinal serotonergic system and herein particularly the serotonin receptor 3 (5-HT3R) may be involved in sugar detection and short-term control of food intake. Using a mouse model, we tested the hypothesis that blocking 5-HT3R prevents the development of sugar-induced obesity. DESIGN: For 8 weeks, C57BL/J6 mice were offered either water containing 30% glucose or plain water in addition to normal chow. The effect of oral treatment with the 5-HT3R antagonist, tropisetron (0.2 mg kg(-1) body weight), on body weight and caloric intake was studied. RESULTS: Total caloric intake and weight gain were significantly increased in mice fed glucose compared with the control group. Tropisetron treatment reduced intestinal motility and almost completely blocked weight gain associated with glucose feeding; however, total caloric intake was not affected. The effect of tropisetron was not associated with a decreased expression of the intestinal and hepatic glucose transporters, SGLT1 (sodium-dependent glucose cotransporter) and Glut2 (glucose transporter 2); instead, the expression of these transporters was slightly increased by the 5-HT3R antagonist. However, expressions of carbohydrate responsive element binding protein and fatty acid synthase, as well as triglyceride levels in the liver were only enhanced in mice fed glucose, but remained unchanged at the level of the control group when mice were treated concomitantly with tropisetron. At the same time, beta-hydroxybutyrate dehydrogenase mRNA expression and plasma levels of ketone bodies were significantly increased. CONCLUSION: Our results suggest that 5-HT3R is a new target for the modulation of hepatic glucose metabolism and for the prevention of obesity.

Cytochrome P450 levels are altered in patients with esophageal squamous-cell carcinoma.

AIM: To investigate the role of cytochrome P450 (CYP) in the carcinogenesis of squamous-cell carcinoma (SCC) in human esophagus by determining expression patterns and protein levels of representative CYPs in esophageal tissue of patients with SCC and controls. METHODS: mRNA expression of CYP2E1, CYP2C, CYP3A4, and CYP3A5 was determined using RT-PCR in both normal and malignant esophageal tissues of patients with untreated esophageal SCC (n = 21) and in controls (n = 10). Protein levels of CYP2E1, CYP2C8, CYP3A4, and CYP3A5 were measured by Western blot. RESULTS: Within the group of SCC patients, mRNA expression of CYP 3A4 and CYP2C was significantly lower in malignant tissue (-39% and -74%, respectively, P < 0.05) than in normal tissue. Similar results were found in CYP3A4 protein levels. Between groups, CYP3A4, CYP3A5, and CYP2C8 protein concentration was significantly higher in non-malignant tissue of SCC patients (4.8-, 2.9-, and 1.9-fold elevation, P < 0.05) than in controls. In contrast, CYP2E1 protein levels were significantly higher in controls than in SCC patients (+46%, P < 0.05). CONCLUSION: Significant differences exist in protein levels of certain CYPs in non-malignant esophageal tissue (e.g. CYP2C8, CYP3A4, CYP3A5, and CYP2E1) between SCC patients and healthy subjects and may contribute to the development of SCC in the esophagus.

Role of retinoic acid receptors in squamous-cell carcinoma in human esophagus.

BACKGROUND: Worldwide, cancer in the esophagus ranks among the 10 most common cancers. Alterations of retinoic acid receptors (e.g. RARalpha, beta, gamma, and RXRalpha, beta, gamma) expression is considered to play an important role in development of squamous-cell carcinoma (SCC), which is the most common esophageal cancer. Alcohol consumption and smoking, which can alter retinoic acid receptor levels, have been identified as key risk factors in the development of carcinoma in the aero-digestive tract. Therefore, the aim of the present study was to evaluate protein levels of retinoic acid receptors (i.e. RARalpha, beta, gamma, and RXRbeta) in esophageal SCC and surrounding normal tissue of patients with untreated SCC and controls. METHODS: All study participants completed a questionnaire concerning smoking and alcohol drinking habits as well as anthropometrical parameters. Protein levels of RARalpha, beta, gamma, and RXRbeta were determined by Western Blot in normal esophageal tissue and tissue obtained from SCC of 21 patients with newly diagnosed esophageal SCC and normal esophageal tissue of 10 controls. RESULTS: Protein levels of RARgamma were significantly lower by approximately 68% in SCC compared to normal surrounding tissue in patients with SCC that smoked and/or consumed elevated amounts of alcohol. Furthermore, RARalpha protein levels were significantly lower (approximately- 45%) in SCC in comparison to normal esophageal mucosa in patients with elevated alcohol intake. When comparing protein levels of retinoic acid receptors between normal tissue of patients with SCC and controls, RARgamma protein levels were found to be significantly higher (approximately 2.7-fold) in normal esophageal tissue of SCC patients than in esophageal tissue obtained from controls. No differences were found for RARalpha, beta, and RXRbeta protein levels between normal esophageal tissue of patients and that of controls. CONCLUSION: In conclusion, results of the present study suggest that alterations of retinoic acid receptors protein may contribute in the development of SCC in esophagus and that in some patients life style (e.g. smoking and alcohol consumption) may be a critical component in the alteration of retinoic acid receptor levels in esophagus.

Nutritional deficiencies in German middle-class male alcohol consumers: relation to dietary intake and severity of liver disease.

OBJECTIVE: The purpose of the present study was to compare the nutrient intake and the nutritional status between German middle-class alcohol consumers and non-drinkers. DESIGN: Cross-sectional study using patients with different stages of alcoholic liver disease (ALD) and healthy volunteers. SETTING: Southern Germany. SUBJECTS: Seventy-six hospitalized German middle-class alcohol consumers with different stages of alcoholic liver disease (ALD) and 22 healthy control subjects. METHODS: Subjects and controls were nutritionally assessed and mineral and vitamin content was measured in blood and urine. RESULTS: When compared with controls, alcohol consumers had significantly higher intakes of total calories, but intake of non-alcoholic calories did not differ between groups (P<0.05). Among drinkers, there was a decrease in percentage of energy derived from protein and fat and a significant increase in carbohydrates (P<0.05). With the exception of vitamin E, micronutrient intake of alcoholics was equal to that of controls; however, blood vitamin (vitamin C, retinol, lycopene, alpha- and gamma-carotene) and trace element (selenium, zinc) concentrations of alcohol-drinking patients were lower than those of non-drinkers. CONCLUSION: From the results of this study it is concluded that in German middle-class male alcohol consumers the status of several micronutrients is disturbed, although dietary intake hardly differs from that in non-alcoholic controls.

Alcohol and retinoids.

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Hirokazu Yokoyama and David Crabb. The presentations were (1) Roles of vitamin A, retinoic acid, and retinoid receptors in the expression of liver ALDH2, by J. Pinaire, R. Hasanadka, M. Fang, and David W. Crabb; (2) Alcohol, vitamin A, and beta-carotene: Adverse interactions, by M. A. Leo and Charles S. Lieber; (3) Retinoic acid, hepatic stellate cells, and Kupffer cells, by Hidekazu Tsukamoto, K. Motomura, T. Miyahara, and M. Ohata; (4) Retinoid storage and metabolism in liver, by William Bosron, S. Sanghani, and N. Kedishvili; (5) Characterization of oxidation pathway from retinol to retinoic acid in esophageal mucosa, by Haruko Shiraishi, Hirokazu Yokoyama, Michiko Miyagi, and Hiromasa Ishii; and (6) Ethanol in an inhibitor of the cytosolic oxidation of retinol in the liver and the large intestine of rats as well as in the human colon mucosa, by Ina Bergheim, Ina Menzl, Alexandr Parlesak, and Christiane Bode.