Microvascular dysfunction in hepatic ischemia-reperfusion injury in pigs.

Although hepatic ischemia-reperfusion (I/R) injury has been investigated for more than two decades, histopathological documentation is limited. As a result, three pig livers with I/R injury and three control livers were injected with colored media, cut into 14 segments, and examined by light microscopy together with microscopic map making. In livers with I/R injury, lobules were identified as being occluded or unoccluded.

Endotoxin, endotoxin-neutralizing-capacity, sCD14, sICAM-1, and cytokines in patients with various degrees of alcoholic liver disease.

Background: Chronic alcohol ingestion leads to endotoxemia which is believed to play an important role in the pathogenesis of alcoholic liver disease (ALD). The purpose of this study was to determine if chronic ethanol consumption, in addition to affecting plasma endotoxin and cytokines, also affects the endotoxin-neutralizing capacity (ENC), sCD14, and sICAM-1, in patients with ALD. A second aim was to identify correlations between these latter parameters, endotoxin, and cytokines, especially IL-10.

The microcirculation during endotoxemia.

The initial responses to endotoxemia are detectable in the microcirculation as a microvascular inflammatory response characterized by activation of the endothelium stimulating these cells from their normal anticoagulant state to a procoagulant state with increased adhesiveness for leukocytes and platelets. Concomitantly, arteriolar tone is lost and reactivity to a variety of agonists is modified. Tissue damage subsequently results not only from reduced perfusion of the exchange vessels, but also from injurious substances released from activated, sequestered leukocytes as well as activated endothelial cells, macrophages, and platelets.

Effect of immunoglobulin G on the hepatic microvascular inflammatory response during sepsis.

The effects of intravenous immunoglobulin G (ivIG) on the hepatic microvascular inflammatory response to sepsis were studied in rats by in vivo microscopy. High doses of ivIG (300 mg/kg bw) (Sandoglobulin or rat IgG) significantly improved the 48 h survival of septic rats from 25-66% when ivIG was given before or immediately after cecal ligation and puncture. Circulating endotoxin also was significantly reduced.

Role of endotoxin in the hepatic microvascular inflammatory response to ethanol.

Kupffer cells (KC) and gut-derived bacterial endotoxin have been implicated in the aetiology of alcoholic liver disease. Using in vivo microscopic methods, we have shown that ethanol ingestion in mice causes a dose dependent increase in leucocyte adhesion and endothelial cell swelling in hepatic sinusoids. Activation of KC is elicited at low doses while depression occurs at high doses and with chronic exposure.

Ethanol exacerbates hepatic microvascular dysfunction, endotoxemia, and lethality in septic mice.

The effect of acute ethanol administration on the hepatic microvascular responses to sepsis was studied. Polymicrobial sepsis was induced 30 min after mice had received ethanol (1 g/kg b.w.

[Endotoxin contents of phytopharmaceuticals: correlation with clinically observed side effects].

Four phytopharmaceutics (Carnivora, Pascotox forte-Injectopas, Esberitox N, Iascador M), which sometimes cause side effects after parenteral administration (fever, rigor, nausea), were examined for their endotoxin content by the kinetic turbidometric Limulus-amebocyte-lysate (LAL) microtitre test. Contaminations of over 10(5) EU/ml (endotoxin units; 1 EU = 0.1 ng of the FDA standard EC-5) were found in correlation with the clinical picture.

Kupffer cell function in host defense.

High-resolution in vivo microscopic methods have been used to explore the responses to endotoxin of Kupffer cells in the livers of anesthetized mice, rats, hamsters, and guinea pigs under a variety of experimental conditions. These include studies of normal animals as well as of animals sensitized or tolerant to endotoxin, C3H/HeJ mice with a low response to endotoxin, mice rendered septic by cecal ligation and puncture, mice with Kupffer cells selectively destroyed by frog virus 3, and rats with portacaval shunts. The functional state of Kupffer cells was evaluated by measuring both the number of these cells per microscopic field that phagocytosed 1.

Tumor necrosis factor and interleukin 1 as mediators of endotoxin-induced beneficial effects.

Bacterial lipopolysaccharides or endotoxins are known to induce tumor necrosis; enhanced nonspecific resistance to bacterial, viral, and parasitic infections and to radiation sickness; and tolerance to lethal doses of endotoxin. These beneficial effects are achieved by pretreatment with minute amounts of endotoxin. Recombinant tumor necrosis factor (TNF) and interleukin 1 (IL-1) are among the mediators capable of invoking radioprotection or resistance to the consequences of cecal ligation and puncture.

No evidence for endotoxin transfer across high flux polysulfone membranes.

Recently, there has been some concern that high-flux membranes may expose dialysis patients to the risk of endotoxin transfer secondary to backfiltration within the dialyzer. To evaluate the safety of high-flux polysulfone dialyzers, we examined in an in vitro recirculation system whether lipopolysaccharides (LPS) and lipid A respectively penetrate from the dialysate to the blood compartment and vice versa using a F-60 hemofilter (Fresenius AG). For the detection of endotoxin, a sensitive, kinetic limulus amebocyte lysate (LAL) microtiter test was used.

Tumor necrosis factor induced stimulation of granulopoiesis and radioprotection.

Human recombinant tumor necrosis factor, TNF, was used to assess its ability to stimulate granulopoiesis and to protect mice against lethal irradiation, effects known to be inducable with TNF-rich postendotoxin serum from BCG infected mice (BCG/ET serum). Although the endotoxin contamination of this TNF preparation is extremely low its effects were compared in endotoxin low responder C3H/HeJ mice and susceptible NMRI mice. TNF is a potent inducer of serum colony stimulating activity, CSA, in both mouse strains.

Deficient Kupffer cell phagocytosis and lysosomal enzymes in the endotoxin-low-responsive C3H/HeJ mouse.

Various substances, including lysosomal enzymes, are produced by Kupffer cells and other macrophages; their release has been implicated in the toxic response to endotoxins. C3H/HeJ mice exhibit little or no response to doses of endotoxin that are lethal in syngeneic C3HeB/FeJ mice. To explore the nature of this deficient response, the Kupffer cells of these mice were studied using in vivo microscopic as well as histochemical and electron microscopical methods.

Species differences in Kupffer cells and endotoxin sensitivity.

The relative species sensitivity to Escherichia coli O111:B4 endotoxin was found to be guinea pig greater than hamster greater than mouse greater than rat. The 50% lethal dose of this endotoxin correlated with both the rate at which single latex particles were phagocytosed by individual Kupffer cells and the number of Kupffer cells in hepatic lobules that phagocytosed latex. The results suggests that the intrahepatic density and the level of activation of Kupffer cells participate in determining endotoxin sensitivity.

Protective effects and role of endotoxin in experimental septicemia.

An experimental model was used in mice in which septicemia develops following invasion of the animals' own intestinal flora after cecal ligation and puncture. Pretreatment with 1 microgram of endotoxin administered 24 hours before surgery significantly reduced the rate of lethality. Bacteria were counted and differentiated in cardiac blood at various times throughout a 48-hour period after induction of septicemia in mice, with and without pretreatment.

In vivo microscopic observations of the responses of Kupffer cells and the hepatic microcirculation to Mycobacterium bovis BCG alone and in combination with endotoxin.

Kupffer cell function and hepatic microvascular hemodynamics were studied by in vivo microscopy in Mycobacterium bovis BCG-infected NMRI mice before and after treatment with minute (0.01 mu mg) tolerance-producing doses and doses causing 70% lethality (0.5 micrograms) of Escherichia coli 0111:B5 endotoxin alone and in combination.

Ability of various adsorbents to bind endotoxins in vitro and to prevent orally induced endotoxemia in mice.

The efficacy of various adsorbents for endotoxin was tested in vitro and in vivo using a murine experimental model of gut-derived endotoxemia. A quantitative limulus amebocyte lysate microtiter test and the limulus amebocyte lysate tube test were used to determine intestinal and circulating levels of endotoxin. Kaopectate, kaolin/pectin mixture, kaolin, pectin, bentonite, charcoal particles, and lactulose were tested for their ability to bind endotoxins both in vitro and in vivo.

Ability of Post-endotoxin serum from BCG-infected mice to induce nonspecific resistance and stimulation of granulopoiesis.

Serum from BCG-infected mice obtained 2 h after injection with endotoxin induced elevated levels of colony-stimulating factor and an increase in splenic granulocyte-macrophage progenitor cells in C3H/HeJ mice. The capacity of such serum to stimulate granulopoiesis may be related to its ability to increase nonspecific resistance to lethal irradiation.

[Quantitative endotoxin determination. Automated kinetic Limulus amebocyte lysate microtiter test with measurement of sample-related interferences].

A turbidometric, automated limulus amoebocyte lysate (LAL) microtiter test has been developed based on the evaluation of the LAL-endotoxin reaction kinetics. The maximal increase in optical density of each reaction mixture within 1 min is recorded. With this method an endotoxin standard curve is achieved which is linear over a concentration range of six decades.

In vivo microscopic studies of the responses of the liver to endotoxin.

In vivo microscopic methods concomitant with electron microscopic and histochemical procedures are being used to explore the sequelae of responses of Kupffer cells and the hepatic microvasculature to endotoxins. To gain further insight into the role of the liver in host defense and nonspecific resistance, the effects of endotoxin also are being studied in animals sensitized to endotoxin (BCG infection) or tolerant to endotoxin (pretreated with detoxified endotoxin, low doses of endotoxin, or in C3H/HeJ mice). The results to date, have demonstrated that endotoxin induces significant alterations in the hepatic microcirculation due to swelling of Kupffer and endothelial cells and the adhesion of leukocytes and platelets to the sinusoid wall.

Aspects of beneficial endotoxin-mediated effects.

The status of hyperreactivity and hyporeactivity following the administration of endotoxin in a susceptible host represents phenomena which are of interest in an attempt to understand the role of endotoxins in pathophysiological events in general. Two experimental approaches designed to examine these events are reported herein; i.v.

Histopathology of mixed anaerobic intraabdominal infection in mice.

This study characterized acute peritonitis and chronic abscess formation resulting from experimental mixed anaerobic infection with Bacteroides melaninogenicus and Fusobacterium necrophorum. At intervals after infection liver and spleen samples were obtained, fixed, and processed for histological examination. An acute to chronic infection progressed in mice infected with this mixture of anaerobic bacteria, whereas, no infection resulted when either organism was injected alone.