Daniell B. Hill

Antioxidants attenuate nuclear factor-kappa B activation and tumor necrosis factor-alpha production in alcoholic hepatitis patient monocytes and rat Kupffer cells, in vitro

UNLABELLEDnThere is increased tumor necrosis factor-alpha (TNF) activity in alcoholic hepatitis (AH).nnnOBJECTIVESnTo examine the effects of antioxidants and glutathione enhancing agents on NF-kappaB activation and TNF production in Kupffer cells and monocytes.nnnDESIGN AND METHODSnIsolated rat Kupffer cells and peripheral blood monocytes from AH patients were treated in vitro. NF-kappaB activation was assessed by electrophoretic mobility shift assay and TNF was measured in cell culture supernatants.nnnRESULTSnMonocytes from AH patients had greater TNF production compared to normal volunteers. Pretreatment with antioxidants or gluathione enhancing agents inhibited TNF production and NF-kappaB activation in both monocytes from normal and AH patients as well as in rat Kupffer cells.nnnCONCLUSIONSnThere may be a therapeutic role for antioxidants or glutathione enhancing agents in disease states with increased TNF activity such as AH.

Chronic alcohol exposure of rats exacerbates apoptosis in hepatocytes and sinusoidal endothelial cells

Background/aims: The liver apoptotic response to chronic alcohol consumption remains poorly characterized. The purpose of this study was to determine in rats the effects of chronic alcohol consumption on the relative magnitude of apoptosis in two major targets of alcohol-induced liver injury: the hepatocyte (Hep) and sinusoidal endothelial cell (SEC). Methods: Rats were fed a liquid diet containing either alcohol or isocaloric amounts of maltose-dextrin for 14 weeks. Hep and SEC were isolated by liver perfusion with collagenase followed by centrifugal elutriation. The state of the liver was assessed on the basis of light microscopic appearance, plasma liver enzymes (alanine and aspartate:2-oxoglutarate amino transferases), and the content of malondialdehyde in Hep. Apoptosis was assessed on the basis of DNA fragmentation in the whole organ (TUNEL), and caspase-3 and -8 activity in isolated cells. A mechanistic approach was also undertaken by measuring mRNA expression and the amount of protein for Fas/CD95, Fas ligand, caspase-3, Bax, Bcl-X(L), and Bcl-2 in the isolated Hep and SEC. Results: The livers of alcohol-fed rats displayed prominent steatosis. Oxidative stress was also present as reflected by an increase in the malondialdehyde content of Hep. Alcohol consumption increased apoptosis in the whole liver assessed on the basis of TUNEL procedure and in Hep and SEC as reflected by significant increase in caspase-3 activity. Of the multiple pro- and anti-apoptotic factors determined in this study, significant changes as assessed by both mRNA expression and the amount of proteins, were observed only in the SEC compartment. Conclusions: The data presented in this study indicate that: (1) chronic alcohol consumption in rats leads to a moderate augmentation of apoptosis in the whole liver and in two liver cell types which are targets for injury in alcoholic liver disease: Hep and SEC; (2) the mechanisms recruited/activated by these two types of liver cells to initiate and execute apoptosis in response to alcohol vary with the cell type.

Increased urinary F2-isoprostane excretion in alcoholic liver disease.

Free radical-induced lipid peroxidation (LP) is thought to be important in alcoholic liver disease (ALD), however, direct demonstration of increased LP in patients with ALD has been difficult. Quantification of F2-isoprostanes (F2-isoP), prostanoids produced by peroxidation of arachidonic acid, in plasma and urine are sensitive and specific indices of LP in vivo. To determine if LP is increased in ALD, 24-h urinary excretion of F2-isoPs were measured in 10 patients hospitalized because of ALD. The mean urinary excretion of the F2-isoP in the ALD patients urine was 9.6+/-3.5 ng/mg creatinine, which was significantly elevated compared to controls urinary excretion, which was 1.7+/-0.2 ng/mg creatinine (p<.01). The urinary excretion of F2-isoP decreased to 3.6+/-1.1 ng/mg creatinine as the patients improved clinically with abstinence over the 1-month period. These data suggest that lipid peroxidation, as assessed by this noninvasive method, is increased in patients with acute ALD and decreases with time as the patients improve clinically with abstinence.

Alcohol-induced sinusoidal endothelial cell dysfunction in the mouse is associated with exacerbated liver apoptosis and can be reversed by caspase inhibition.

The purpose of this study was to determine if a correlation exists between alcohol-induced liver sinusoidal endothelial cell (SEC) dysfunction and alcohol-induced augmented liver apoptosis in the mouse. Mice were fed an alcohol-containing liquid diet for 7 weeks. On the last day of feeding, the animals were treated with the pan-caspase inhibitor IDN1529 (N-[(indole-2-)-alaninyl]-3-amino-4-oxo-fluoropentanoic acid), killed, and plasma amino transferase activity, plasma hyaluronan, liver caspase-3 activity, the frequency of apoptotic nuclei in the liver, liver histology and electron microscopic appearance evaluated. Alcohol feeding significantly increased (2.5-fold) plasma hyaluronan levels, frequency of apoptotic nuclei (20-fold), and caspase-3 activity (1.7-fold), but did not affect plasma amino transferase activity. Transmission electron microscopy revealed that SEC was among the cell types undergoing apoptosis. Livers of alcohol-fed mice displayed marked fat accumulation without necrosis or fibrosis. Treatment of mice with IDN1529 reversed the alcohol effects on plasma hyaluronan levels, liver caspase-3 activity, and frequency of apoptotic nuclei. However, the inhibitor did not prevent fat accumulation in the liver. These data suggest that alcohol-induced exacerbation of apoptosis in the liver, which extends to the SEC, causes functional impairment of the sinusoidal lining and can be reversed by caspase inhibition.

MECHANISMS OF HEPATIC INJURY IN ALCOHOLIC LIVER DISEASE

Essentially all patients with significant alcoholic liver disease (ALD) have clinical manifestations of malnutrition. 101 Work by Lieber and others, however, has demonstrated that ALD can occur despite adequate nutrition. 85,86 This suggests that the liver injury of ALD is attributable to direct toxic effects of alcohol and its metabolites or the consequences of alcohol metabolism. Major research efforts into these areas have uncovered several potential mechanisms that may play a role in the liver injury of ALD. In all likelihood, several mechanisms operate simultaneously to initiate, potentiate, or perpetuate liver injury once it is initiated in clinical ALD. In addition, the initiating events or factors in alcoholic liver injury and the reasons why some individuals are predisposed to ALD are not known. Although interesting data recently were reported on the mechanisms of liver fibrosis in ALD, alcoholic hepatitis (AH) and acute liver injury are the foci of our discussion because most investigators agree that AH is an intermediate but potentially reversible stage of ALD. It is hoped that further knowledge concerning the pathogenesis of AH will allow the development of more effective treatments for this potentially lethal disease. The concepts of liver injury caused by alcohol-related oxidative stress (lipid peroxidation), immune response (cytokines), fatty acid metabolites, acetaldehyde production (protein–acetaldehyde adduct formation), mitochondrial dysfunction, and synergism of viral liver injuries, have been proposed. 81,145 These are the areas that have received major investigative attention over the past decade and are reviewed in this article.

A role for Helicobacter pylori in the gastrointestinal complaints of eating disorder patients

UNLABELLEDnEating disorder patients frequently present with gastrointestinal complaints. Helicobacter pylori is an etiologic factor in type B gastritis, gastric and duodenal ulcers, and may cause nausea and anorexia.nnnOBJECTIVEnTo determine whether or not there is an increased prevalence of H. pylori infection in patients with eating disorders.nnnMETHODnSerum H. pylori IgG antibody and gastrointestinal symptoms were assessed in 32 patients admitted for inpatient treatment of anorexia nervosa and/or bulimia nervosa.nnnRESULTSnEating disorder patients did not have an increased rate of detectable serum H. pylori IgG antibody.nnnDISCUSSIONnThere is not an increased prevalence of H. pylori infection in eating disorder patients. Thus, the increased frequency of gastrointestinal complaints in eating disorder patients cannot be attributed to H. pylori infection.

Noninvasive detection of Helicobacter pylori colonization in stomach using [11C]urea

SummaryHelicobacter pylori is associated with chronic type B gastritis. Diagnosis can be made on gastric biopsy specimens and noninvasively using [13C]-or [14C]urea breath tests. Both breath tests require meticulous breath collection, and false positive results are possible from urease producing oral-pharyngeal flora. We used [11C]urea, a positronemitting radionuclide allowing dynamic imaging, to measure metabolism of urea in the stomach of biopsy documentedH. pylori-positive patients. [11C]urea was synthesized from11CO2 produced using a Van de Graaff accelerator and administered with [99mTc]DTPA to control for loss of radioactivity via gastric emptying. Images were obtained externally by gamma camera every minute and11CO2 was monitored in the breath continuously for 30 min. AnH. pylori-positive patient exhibited a99mTc/11C activity ratio of 2.1 in the stomach 10–20 min following administration, compared to a 1∶1 ratio in a negative control, indicating metabolism of urea to11CO2 with subsequent diffusion of11C activity out of the stomach. The11C activity in the breath peaked at 10–20 min in theH. pylori-positive patients. The short half-life of carbon-11 (20.4 min) alleviates radiation safety concerns and results in low absorbed radiation doses to patients.