Background/Aim: The generation of reactive oxygen species by activated Kupffer cells (KC) may contribute to reperfusion injury of the liver during liver transplantation or resection. The aim of our present studies was to investigate (1) prevention of hepatic reperfusion injury after warm ischemia by administration of the antioxidant glutathione (GSH) and (2) whether GSH confers protection through influences on KC toxicity. Methods: Isolated perfused rat livers were subjected to 1 h of warm ischemia followed by 90 min of reperfusion without (n = 5) or with GSH or catalase (n = 4–5 each). Selective KC activation by zymosan (150 µg/ml) in continuously perfused rat livers was used to investigate KC-related liver injury. Results: Postischemic infusion of 0.1, 0.5, 1.0 and 2.0 mM GSH, but not 0.05 mM GSH prevented reperfusion injury after warm ischemia as indicated by a marked reduction of sinusoidal LDH efflux by up to 83 ± 13% (mean ± SD; p < 0.05) and a concomitant significant improvement of postischemic bile flow by 58 ± 27% (p < 0.05). A similar protection was conveyed by KC blockade with gadolinium chloride indicating prevention of KC-related reperfusion injury by postischemic GSH treatment. Postischemic treatment with catalase (150 U/ml) resulted in a reduction of LDH efflux by 40 ± 9% (p < 0.05). Accordingly, catalase as well as GSH (0.1–2.0 mM) nearly completely prevented the increase in LDH efflux following selective KC activation by zymosan in continously perfused rat livers. Conclusion: Postischemic administration of GSH protects the liver against reperfusion injury after warm ischemia. Detoxification of KC-derived hydrogen peroxide seem to be an important feature of the protective mechanisms.

Hepatotoxicity Following Desflurane AnesthesiaTo the Editor:Several fluorinated inhalation anesthetics have been associated with hepatotoxicity. Although halothane-associated hepatitis is most common, desflurane is considered to be the safest inhalation anesthetic especially for patients who may have been sensitized by previous halothane exposure. However, we report a patient who experienced severe hepatotoxicity after desflurane anesthesia and who may have been sensitized by previous halothane exposure.A 37-year-old, obese woman underwent a fixation of a tibial shaft fracture in general anesthesia. The patient was on no regular medication, she had never received blood products, and had no history of intravenous drug abuse, tattoos, acupuncture, or occupational exposure to hepatoxins. There was no family history of liver disease. Alcohol consumption was less than 10 g/mo. The patient had a history of drug allergies against penicillin, nickel, and cobalt. Previous surgical and anesthetic history included an appendectomy in 1979 and a tonsillectomy in 1980 for which no records were available and a cesarean section in 1989 for which the patient received droperidol, succinylcholine, alcuronium, nitrous oxide, oxygen, and isoflurane. Six weeks postoperatively, the patient developed unexplained hepatitis with a transient elevation of liver enzymes, jaundice and pruritus, malaise, and nausea. An erythematous rash over the buttocks and thighs was interpreted as a gestational dermatosis and treated with polidocanol and mepivacain gel. Clinical signs and laboratory parameters completely normalized after 3 weeks of observation. In 1990, the patient underwent a salpingectomy followed by a total abdominal hysterectomy in 1994 for which the patient received fentanyl, droperidol, ketamine, alcuronium, nitrous oxide, oxygen, and halothane; each of these anesthesias were uneventful. On January 14, 1998 a fixation of a tibial shaft fracture was performed. General anesthesia was induced by etomidat and alcuronium, and for analgesia the patient received metamizole and piritramide intravenously. Anesthesia was maintained by a mixture of oxygen in nitrous oxide and desflurane and intravenous fentanyl. The patient remained hemodynamically stable throughout the operation, and no blood products were given. She was discharged from the hospital 10 days later after an uneventful postoperative period. Twelve days postoperatively, the patient experienced a macular erythematous itching rash starting at both palms and spreading over the whole upper body. Two days later, the patient complained of increasing jaundice, dark urine, pruritus, malaise, nausea, and epigastric abdominal pain. Laboratory tests showed 1,280 eosinophils/ µL, markedly increased liver enzymes (alanine transaminase 1,776 U/L, aspartate transaminase 1,258 U/L, ␥-glutamyltranspeptidase 48 U/L, and alkaline phosphatase 185 U/L), total bilirubin (29.4 mg/dL) and ammonia (61 µmol/L), and a reduced synthesis of clotting factors (prothrombin time 37%, partial thromboplastin time 5...

Kupffer cells (KCs), the resident macrophages of the liver, contribute prominently to liver injury by inflammatory mediators. Pre-conditioning with the atrial natriuretic peptide (ANP), known also as a regulator of macrophage functions, attenuates hepatic ischemia-reperfusion injury. Therefore, the aim of this study was to determine the presence of functional ANP receptors on isolated KCs and to investigate whether this hepatoprotective hormone influences the activation of KCs. KCs were isolated by collagenase/pronase digestion followed by elutrial centrifugation and cultured for 1 to 3 days. Intracellular cyclic guanosine 3'5'-monophosphate (cGMP) concentrations were measured by radioimmunoassay after treating the cells with sodium nitroprusside or ANP. KCs were stimulated with bacterial lipopolysaccharide in the presence or absence of ANP, and inflammatory mediators were determined. Phagocytosis was assayed using Coumarin-labeled latex particles and flow cytometric analysis. Treatment of KCs with ANP but not with sodium nitroprusside resulted in a significant elevation of intracellular cGMP levels indicating functional type A natriuretic peptide receptors (NPR-As). ANP significantly reduced lipopolysaccharide (LPS)-induced tumor necrosis factor alpha (TNFalpha) secretion, paralleled by an increased cell-associated TNFalpha. LPS-induced TNFalpha mRNA expression was not affected. ANP significantly increased phagocytotic activity of KCs via NPR-A. No effect of ANP on LPS-activated inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 protein levels, iNOS mRNA expression, nitric oxide, and PGE2-production was observed. We demonstrated functional cGMP-dependent ANP receptors in isolated rat KCs. ANP reduced TNFalpha release possibly by influencing post-translational processing of TNFalpha in LPS-activated KCs. In addition, we demonstrated that ANP enhances phagocytosis in KCs. These effects may contribute to the hepatoprotective actions of ANP.

The present study was designed to determine whether antihypertensive agents known to affect the renin-angiotensin-aldosterone (RAA) system might affect the elevation of blood pressure induced by chronic exposure to cold. Spironolactone, a mineralocorticoid receptor blocker, was added to the food and administered to rats chronically exposed to cold. In addition, clonidine, an α₂-adrenergic agonist and inhibitor of renin secretion, was administered to another group of cold-exposed rats by daily intraperitoneal injection. A warm-adapted and a cold-treated control group were also used. Chronic administration of spironolactone prevented the development of hypertension but failed to prevent other adaptive physiological changes characteristically occurring during exposure to cold and seen in the cold-treated control rats. Thus, increased weight of the heart, kidneys, adrenals and brown adipose tissue, increased dipsogenic responsiveness to angiotensin II, increased urinary outputs of norepinephrine and epinephrine, and increased food and water consumption were observed in all rats, treated and untreated, during exposure to cold. Similarly, daily injection of clonidine attenuated the elevation of blood pressure but also failed to prevent the other adaptive physiological changes characteristic of cold. These results are consistent with the hypothesis that the RAA system plays a role in the development of the cold-induced elevation of blood pressure.