The vasorelaxant hormone relaxin induces changes in liver sinusoid microcirculation: a morphologic study in the rat.

This study shows that specialized contractile endothelial cells exist in rat liver sinusoids which may be involved in the local control of hemodynamics and which are sensitive to vasoactive agents, including the vasorelaxant hormone relaxin. Male rats were treated with 10 microg relaxin for 4 days; phosphate-buffered saline (PBS)-treated rats were the controls. For comparison, rats treated with relaxin together with the NO-synthase inhibitor N(omega)-nitro-l -arginine methyl ester (L-NAME), and rats treated with the vasodilator taurodeoxycholic acid or the vasoconstrictor ethanol were investigated. Liver fragments were studied morphologically and morphometrically. In the control rats, peculiar contractile cells were present in the endothelial lining. These cells had abundant myofilaments and formed cytoplasmic blebs projecting into and often occluding the lumen. In the ethanol-treated rats, sinusoids were constricted and filled with cytoplasmic blebs. In the relaxin-treated rats, sinusoids were markedly dilated and the cytoplasmic blebs nearly disappeared. Similar findings were observed in the taurodeoxycholic acid-treated rats. The effects of relaxin were blunted by L-NAME, suggesting that the relaxin action involves an NO-mediated mechanism.     

Melatonin prevents lipopolysaccharide-induced hyporeactivity in rat

Melatonin (MT) is the principal secretory product of the pineal gland and its role as an immumo-modulator is well established. Recent evidence shows that MT exerts protective effects in septic shock, hemorrhagic shock and inflammation. Lipopolysaccharide (LPS), from Escherichia coli, administered to animals directly stimulates a number of cells and systems to produce various inflammatory mediators. LPS-induced septic shock is characterized by hypotension and vascular hyporeactivity to contracting agents. In particular, the reactive oxygen species such as superoxide and nitric oxide (NO) contribute to the pathophysiology of septic shock. In this study, we demonstrate that MT pretreatment prevents the hyporeactivity to phenylephrine in vivo and in aorta rings collected from rats treated with the endotoxin. The beneficial effect of MT seems related to its antioxidant properties and with inhibition of inducible nitric oxide synthase (iNOS) protein expression, reduction of NO production and nitrotyrosine formation, in aorta, preventing vascular, and endothelial injury. Additionally, we first demonstrate, that MT inhibited nuclear enzyme poly (ADP-ribose) synthetase activation in vascular tissue. The current study underlined the protective effect of MT on the vascular dysfunction associated with septic shock, data that could support the clinical use of MT in human endotoxemia.     

Kupffer cell inactivation alleviates ethanol-induced steatosis and CYP2E1 induction but not inflammatory responses in rat liver

BACKGROUND/AIMS: Gadolinium chloride inactivates Kupffer cells and alleviates alcohol-induced liver lesions. We investigated the mechanism of gadolinium chloride protection after oral ethanol feeding. METHODS: Rats were maintained ethanol-intoxicated for 6 weeks by feeding ethanol in a low-carbohydrate/high-fat liquid diet. Macrophages were inactivated by intravenous administrations of gadolinium chloride. At termination, liver samples and cell lysates obtained from the periportal and perivenous region were analyzed for histopathology, mRNA expression of endotoxin-associated parameters and cytokines and for enzymes involved in oxidative stress. RESULTS: Ethanol treatment alone caused marked microvesicular/macrovacuolar steatosis and focal inflammation. Gadolinium significantly alleviated pathology, by reducing steatosis but not inflammation. Gadolinium treatment eliminated ED2 immunopositive Kupffer cells, which were larger and more frequent periportally. Ethanol significantly increased the mRNA expression of the endotoxin (LPS) receptor CD14 and the LPS binding protein LBP, but not that of the pro-inflammatory cytokines TNF-alpha and IL-1beta. The mRNA of CD14 was found to be expressed preferentially in the perivenous region, but gadolinium treatment had no significant effect on the expression or the distribution. However, gadolinium significantly moderated the ethanol induction of CYP2E1 and this effect correlated to the degree of steatosis. Ethanol increased glutathione transferase and reduced glutathione peroxidase activity, but these changes persisted after gadolinium treatment. CONCLUSIONS: Our results suggest that gadolinium chloride reduces symptoms of ALD mainly by counteracting steatosis, and that CD14-positive Kupffer cell populations are not involved in gadolinium protection. The strong correlation between pathology and CYP2E1 induction might suggest a steatopathogenic role for this enzyme.     

一种改良大鼠肝脏Kupffer细胞分离方法

目的观察改良大鼠肝脏Kupffer细胞(KCs)分离方法获取KCs的效果。方法参照Akira提供的方法进行以下改进:①前灌注液在体灌注,Ⅳ型胶原酶离体灌注消化;②Percoll分离液不连续密度梯度离心;③台盼蓝染色检测分离细胞的活度;④选择性贴壁法纯化获取的细胞;⑤吞墨实验、DAB染色及CD163细胞免疫荧光法鉴定所分选细胞。结果肝脏KCs的获得量为(3±1.5)×105/g鼠肝,细胞活度>92%;光镜下细胞呈圆形,培养24 h后呈梭形或多角形;具有较强的吞噬能力,DAB染色呈"煎蛋"样,荧光显微镜下>99%为KCs。结论改良的大鼠肝脏KCs分离方法较Akira法能够获取更高纯度的KCs,简捷经济,值得推广。     

Age-related changes in the endocytic capacity of rat liver Kupffer and endothelial cells

There are many indications that the functional capacity of the reticuloendothelial system (RES) declines with age. The aim of this study was to investigate the cellular basis of age-related changes in the clearance function of the RES. The experiments were focused mainly on Kupffer and endothelial cells of the liver which represent a major part of the RES and are primarily responsible for clearance of colloidal material from the circulation. The clearance capacity of the RES was tested clinically and experimentally by intravenous injection of colloids, such as radiolabeled heat-aggregated colloidal albumin. Age-related changes in the endocytosis of 125I-labeled colloidal albumin (CA) in rats were determined by clearance and organ distribution of different doses of intravenously injected CA, uptake of CA by Kupffer and endothelial liver cells in vivo as determined after isolation of the cells from injected rats and kinetic studies on CA uptake by Kupffer cells in culture. The results show that, at a low dose, the clearance of CA is primarily determined by liver blood flow. At a higher saturating dose, plasma clearance and uptake by the liver are not significantly decreased with age. Endocytosis by endothelial cells, which accounts for about 60% of that of the whole liver, is also unchanged with age. In contrast, a significant decrease in endocytic capacity was observed for Kupffer cells in vivo. This age-related functional decline was also observed in Kupffer cells which were isolated from rats of different ages and maintained in culture.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of Kupffer cell inactivation on graft survival and liver regeneration after partial liver transplantation in rats

BACKGROUND: Gadolinium chloride(Gd Cl3) selectively inactivates Kupffer cells and protects against ischemia/reperfusion and endotoxin injury. However, the effect of Kupffer cell inactivation on liver regeneration after partial liver transplantation(PLTx) is not clear. This study was to investigate the role of Gd Cl3 pretreatment in graft function after PLTx, and to explore the potential mechanism involved in this process.METHODS: PLTx(30% partial liver transplantation) was performed using Kamada's cuff technique, without hepatic artery reconstruction. Rats were randomly divided into the control low-dose(5 mg/kg) and high-dose(10 mg/kg) Gd Cl3 groups. Liver injury was determined by the plasma levels of alanine aminotransferase and aspartate aminotransferase, liver regeneration by PCNA staining and Brd U uptake, apoptosis by TUNEL assay. IL-6 and p-STAT3 levels were measured by ELISA and Western blotting.RESULTS: Gd Cl3 depleted Kupffer cells and decreased animal survival rates, but did not significantly affect alanine aminotransferase and aspartate aminotransferase(P0.05). Gd Cl3 pretreatment induced apoptosis and inhibited IL-6 overexpression and STAT3 phosphorylation after PLTx in graft tissues.CONCLUSION: Kupffer cells may contribute to the liver regeneration after PLTx through inhibition of apoptosis and activation of the IL-6/p-STAT3 signal pathway.     

Inactivation of Kupffer cells by gadolinium administration prevents lipopolysaccharide-induced decrease in liver insulin-like growth factor-I and IGF-binding protein-3 gene expression

Gram-negative bacterial infection or treatment of animals with bacterial lipopolysaccharide (LPS) induces a catabolic state with proteolysis, liver injury and an inhibition of the insulin-like growth factor-I (IGF-I) system. The purpose of this work was to elucidate the role of Kupffer cells in LPS-induced inhibition of the IGF-I/IGF-binding protein-3 (IGFBP-3) system. Adult male Wistar rats were either pretreated with the Kupffer cell inhibitor gadolinium chloride (10 mg/kg, i.v., 24 h prior to LPS exposure) or saline vehicle. Rats received two i.p. injections of 1 mg/kg LPS (at 17:30 and 08:30 h the following day) and were killed 4 h after the second injection. LPS administration induced a significant decrease in body weight and in serum concentrations of IGF-I and IGFBP-3 (P < 0.01), as well as in their gene expression in the liver. LPS-injected rats had increased serum concentrations of ACTH, corticosterone (P < 0.05), tumour necrosis factor-alpha (TNF-alpha) and nitrites (P < 0.01). Pretreatment of the animals with gadolinium chloride blocked the inhibitory effect of LPS on body weight, and on serum concentrations of IGF-I, IGFBP-3 and nitrites, as well as growth hormone receptor (GHR), IGF-I and IGFBP-3 gene expression in the liver. In contrast, gadolinium chloride administration did not modify the stimulatory effect of LPS on serum concentrations of ACTH, corticosterone and TNF-alpha. These results suggest that Kupffer cells are important mediators in the inhibitory effect of LPS on GHR, IGF-I and IGFBP-3 gene expression in the liver, leading to a decrease in serum concentrations of IGF-I and IGFBP-3.     

Insulin prevents liver damage and preserves liver function in lipopolysaccharide-induced endotoxemic rats

BACKGROUND/AIMS: Liver integrity and function are crucial for survival of patients suffering from trauma, operations or infections. Insulin decreased mortality and prevented the incidence of multi organ failure and infection in critically ill patients. The aim of the present study was to determine whether insulin exerts positive effects on hepatic homeostasis and function during endotoxemia. METHODS: Endotoxemic rats received either saline or insulin. Hepatic morphology and function was determined by measuring the effect of insulin on liver proteins, enzymes, hepatocyte apoptosis and proliferation including caspases-3 and -9 and Bcl-2. Intrahepatic ATP, glucose and lactate concentration were determined by bioluminescence. To determine possible molecular changes the effect of insulin on hepatic cytokine mRNA and gene profile analysis were assessed. RESULTS: Insulin significantly improved hepatic protein synthesis by increasing albumin and decreasing c-reactive protein, P<0.05. Insulin attenuated hepatic damage by decreasing AST and ALT, P<0.05. Improved liver morphology was due to decreased hepatocyte apoptosis along with decreased caspase-3 concentration and increased hepatocyte proliferation along with Bcl-2 concentration, P<0.05. Insulin decreased hepatic IL-1beta, IL-6 and MIF mRNA and improved hepatic glucose metabolism and glycolysis, P<0.05. GeneChip analysis revealed an anti-inflammatory effect of insulin. CONCLUSIONS: Insulin improves hepatic integrity, hepatic glucose metabolism and hepatic function by increasing cell survival and attenuating the hepatic inflammatory response in endotoxemic rats.     

Suppression of lipopolysaccharide-induced nitric oxide synthase expression by platelet-activating factor receptor antagonists in the rat liver and cultured rat Kupffer cells.

Excessive nitric oxide (NO) generated by hepatic cells in response to lipopolysaccharide (LPS) and inflammatory substances (e.g., platelet-activating factor [PAF]) is a key contributor to the pathophysiological outcomes observed in the liver during sepsis. In rats subjected to liver-focused endotoxemia, inducible nitric oxide synthase (iNOS) levels in the intact liver were elevated by 6 hours; cell-specific expression of iNOS messenger RNA (mRNA) was Kupffer cells (KCs), endothelial cells, and hepatocytes. Elevated serum alanine transaminase (ALT) levels at 6 hours confirmed hepatic damage. Pretreatment of endotoxemic rats with PAF receptor antagonists BN 50739 or WEB 2170 reduced serum ALT and iNOS mRNA levels in the intact liver. Pretreatment of cultured KCs with BN 50739 or WEB 2170 inhibited both LPS and PAF-induced iNOS mRNA formation. In addition, LPS-induced iNOS protein levels in KCs pretreated with BN 50739 or WEB 2170 were decreased. Exposure of KCs to either LPS or PAF caused the translocation of the p65 subunit of nuclear factor kappa B (NF-kappaB) into the nucleus and this process was attenuated by BN 50739 and WEB 2170. There was concomitant inhibition of LPS-dependent degradation of the inhibitory protein IkappaBalpha and increase in intracellular Ca(2+) in KC treated with BN 50739 or WEB 2170. Also, in KCs, LPS was able to induce iNOS mRNA expression independent of CD14. This response was inhibited by pretreatment of KCs with either BN 50739 or WEB 2170. Our findings indicate that PAF receptor antagonists convey protection against hepatocellular injury accompanied by a decrease in nitric oxide (NO) formation in the livers of endotoxemic rats.     

A new method to monitor Kupffer cell phagocytosis continuously in perfused rat liver

A new method was developed to monitor Kupffer cell phagocytosis continuously in perfused liver using a fluorescent probe, rhodamine-gelatin, synthesized from gelatin and rhodamine isothiocyanate. In perfused rat liver, phagocytosis by Kupffer cells was assessed both by uptake of the dye and from fluorescence measured from the liver surface. Uptake of rhodamine-gelatin and surface fluorescence (520----585 nm) increased as perfusate concentrations of rhodamine-gelatin were elevated. Histological examination revealed that fluorescence caused by rhodamine-gelatin was concentrated in cells lining the sinusoid. Furthermore, when hepatic parenchymal, endothelial and Kupffer cells were isolated by centrifugal elutriation after pretreatment in vivo with rhodamine-gelatin, the fluorescent label was detected nearly exclusively in the Kupffer cell fraction. Fluorescence of rhodamine-gelatin from the liver surface was directly proportional to uptake of rhodamine-gelatin, indicating that measurement of surface fluorescence could be used as an index of phagocytic activity of Kupffer cells. Uptake of rhodamine-gelatin and fluorescent labeling of sinusoidal cells were inhibited nearly completely by dextran sulfate, which decreases phagocytic activity, and were increased by about 50% by pretreatment with endotoxin, which stimulates phagocytosis. This new method was combined with standard procedures to monitor parenchymal cell function (e.g., oxygen uptake and release of lactate dehydrogenase), Kupffer cell phagocytic activity and parenchymal cell injury simultaneously during perfusion with the hepatotoxicant allyl alcohol. Activation of phagocytosis by Kupffer cells monitored by rhodamine-gelatin fluorescence occurred within 5 min of addition of allyl alcohol. On the other hand, parenchymal cell injury, assessed from release of lactate dehydrogenase, did not begin until 40 min and reached maximal values at around 90 min.(ABSTRACT TRUNCATED AT 250 WORDS)     

S-Adenosylmethionine attenuates lipopolysaccharide-induced liver injury by downregulating the Toll-like receptor 4 signal in Kupffer cells

Purpose

S-Adenosylmethionine (SAM) is beneficial for lipopolysaccharide (LPS)-induced liver injury, but its molecular basis is not fully understood. The present study was carried out to investigate the effects of SAM on LPS signal transduction and its possible mechanism.

Methods

An animal model of LPS-induced liver injury was established by intraperitoneally injecting mice with 10 mg/kg LPS pretreatment with or without SAM (170 μmol/kg body weight). Toll-like receptor 4 (TLR4) protein expression in liver tissues and the tumor necrosis factor alpha (TNF-α) secretion level in serum were detected by immunohistochemistry and enzyme-linked immunosorbent assay, respectively. Then, Kupffer cells (KCs) were isolated and challenged with LPS, with or without SAM pretreatment (1,000 μM), and the expressions of TLR4 and myeloid differentiation primary response protein (MYD88) were assayed at the mRNA and protein levels. The activities of nuclear factor-kappa B (NF-κB) and p38 mitogen-activated protein kinase (MAPK) were also analyzed using Western blotting.

Results

SAM significantly improved the survival rate of endotoxemic mice (p < 0.05) and decreased TNF-α levels in serum (p < 0.05). Simultaneously, SAM also attenuated LPS-induced liver injury and expression of TLR4 and MYD88 in the hepatic sinusoid. Moreover, TLR4 and MYD88 gene and protein expressions were downregulated by SAM pretreatment in LPS-stimulated KCs. Finally, SAM did not affect NF-κB-p65 translocation into the nucleus (p > 0.05), but significantly inhibited p38 MAPK activation (p < 0.05).

Conclusions

SAM attenuated liver injury and improved the survival rate in endotoxemic mice by decreasing the TNF-α expression. The downregulative effect of SAM on TNF-α was mediated by suppressing activation of the TLR4/MAPK signaling pathway.     

Regulation of hyaluronate synthesis in rat liver fat storing cell cultures by Kupffer cells

During fibrogenesis in chronically inflamed liver the concentration of extracellular matrix hyaluronate increases several-fold, but the mechanism of hyaluronate accumulation has hitherto been unknown. We studied the effect of stimulated Kupffer cells on the synthesis and secretion of hyaluronic acid by rat liver fat storing cells, the main hyaluronate-producing cell type in liver. Conditioned medium was harvested from monolayers of Kupffer cells activated by exposure for 24 h to zymosan and lipopolysaccharide. Addition of these Kupffer cell media to monolayers of fat storing cells stimulated more than 2-fold the incorporation of [3H]glucosamine into both total glycosaminoglycans and hyaluronic acid in the medium. The synthesis rate of hyaluronic acid was enhanced more strongly than that of sulfated glycosaminoglycans, resulting in a significant fractional increase of hyaluronate. The concentration of hyaluronate measured with a radiometric assay in the medium of fat storing cells exposed to Kupffer cell media was raised 2.6-fold within 24 h in comparison to untreated cultures. The synthesis rate of hyaluronate in untreated fat storing cells of 4.2 +/- 0.8 micrograms/mg DNA per h increased up to 8.2 +/- 0.9 micrograms/mg DNA per h in the presence of Kupffer cell conditioned medium. The results demonstrate an activation of hyaluronate synthesis in fat storing cells by Kupffer cell factor(s), a mechanism which might be of relevance for the strong absolute and fractional increase of hyaluronate in the extracellular matrix of fibrotic livers.     

Glutathione treatment protects the rat liver against injury after warm ischemia and Kupffer cell activation

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 micro g/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.     

Effect of matrine on Kupffer cell activation in cold ischemia reperfusion injury of rat liver

AIM: To study the effect of matrine on activation of Kupffer cell during cold ischemia and reperfusion injury in rat orthotopic liver transplantation (OLT). METHODS: 168 syngeneic SD rats were randomly divided into four groups: untreated group, small-dose treated group, large-dose treated group and sham operation group. After 5 hours of preservation in Ringer's (LR) solution, orthotopic implantation of the donor liver was performed. At 1 h, 2 h, 4 h and 24 h after reperfusion of the portal vein, 6 rats were killed in each group to collect the serum and the liver for assay and pathology. RESULTS: Matrine markedly inhibited the activation of Kupffer cells and their release of tumor necrosis factor (TNF). TNF cytotoxicity level at 2 h decreased significantly by matrine treatment (7.94+/-0.42, 2.39+/-0.19 and 2.01+/-0.13 U/ml, respectively; P<0.01), so did the other three time points. The level of hylluronic acid (HA) and alanine transaminase (ALT) decreased significantly in both treated groups, and matrine treatment markedly ameliorated focal necrosis of hepatocytes, inflammatory cells aggregating, rounding and detachment of sinusoidal endothelial cells (SEC). And no significant difference was observed between the treated groups. CONCLUSION: Matrine can inhibit the activation of Kupffer cell and prevent the donor liver from cold preservation and reperfusion injury in rat orthotopic liver transplantation.     

Effect of matrine on Kupffer cell activation in cold ischemia reperfusion injury of rat liver

AIM: To study the effect of matrine on activation of Kupffer cell during cold ischemia and reperfusion injury in rat orthotopic liver transplantation (OLT).METHODS: 168 syngeneic SD rats were randomly divided into four groups: untreated group, small-dose treated group, large-dose treated group and sham operation group. After 5 hours of preservation in Ringer's (LR) solution, orthotopic implantation of the donor liver was performed. At 1 h, 2 h, 4 h and 24 h after reperfusion of the portal vein, 6 rats were killed in each group to collect the serum and the liver for assay and pathology.RESULTS: Matrine markedly inhibited the activation of Kupffer cells and their release of tumor necrosis factor (TNF). TNF cytotoxicity level at 2 h decreased significantly by matrine treatment (7.94±0.42, 2.39±0.19 and 2.01±0.13 U/ml,respectively; P＜0.01), so did the other three time points. The level of hylluronic acid (HA) and alanine transaminase (ALT) decreased significantly in both treated groups, and matrine treatment markedly ameliorated focal necrosis of hepatocytes, inflammatory cells aggregating, rounding and detachment of sinusoidal endothelial cells (SEC). And no significant difference was observed between the treated groups.CONCLUSION: Matrine can inhibit the activation of Kupffer cell and prevent the donor liver from cold preservation and reperfusion injury in rat orthotopic liver transplantation.     

Neuronal aging in cultures. An electron-microscopic study

Lipofuscin formation in the neurons of spinal ganglia of one month old male Wistar rats, maintained in culture for a period of 4 weeks, has been investigated. The dorsal root ganglia were explanted on collagen coated coverslips and carried in Maximow double coverslip assemblies. The cultured ganglia were studied in sections after OsO₄ fixation and Epon embedding. The age pigment is found as early as one month in spinal ganglia neurons. In culture an accelerated accumulation of lipofuscin occurs and after four weeks of maintenance of the spinal ganglia, the neurons at different rates degenerate. The pigment bodies, some vacuolated others not, are often seen to be bound by a double limiting membrane and are found in close topographical and morphological association to mitochondria. The pigment from the ganglion cells can be removed by cytoplasmic protrusions which accounts also for the presence of pigment bodies in the satellite cells.     

库普弗细胞在非酒精性脂肪性肝病中的作用

库普弗细胞(KC)是定居于肝内的单核-巨噬细胞,其表面存在多种受体,可被多种配体激活,通过产生细胞因子、炎症介质和活性氧簇等在多种肝损伤的发病过程中起重要作用。近年的研究显示KC也参与非酒精性脂肪性肝病的发病机制,在胰岛素抵抗、氧应激和炎症过程中起重要作用,因此控制KC的活化将有助于减轻或阻止非酒精性脂肪性肝病的的发展。     

Kupffer cell erythrophagocytosis and graft-versus-host hemolysis in liver transplantation

BACKGROUND & AIMS: Graft-versus-host hemolysis (GVHH) syndrome develops in approximately half of patients undergoing ABO-unmatched liver transplantation. The clinical and laboratory presentations of GVHH syndrome often mimic acute rejection, leading to liver biopsy for definitive diagnosis. The purpose of this study was to investigate if there are specific histological findings that permit diagnosis of GVHH syndrome and to assess the relationship between GVHH syndrome and rejection. METHODS: Clinical and laboratory evidence of GVHH syndrome, results of liver biopsy, and clinical outcome were assessed in 30 ABO- unmatched liver transplant recipients. Biopsy results were compared with those of two control groups consisting of patients who had normal liver test findings (protocol biopsy) and rejection. RESULTS: Sixteen of the 30 patients (53%) had evidence of GVHH syndrome. Erythrophagocytosis was noted in each biopsy specimen, and the degree of phagocytosis correlated significantly with the amount of blood given after postoperative day 5 (r = 0.9; P < 0.02). Electron-microscopic studies performed randomly in 5 patients showed that the red cells were located in Kupffer cells. In contrast, erythrophagocytosis was minimal in the two control groups. Despite an incidence and severity of rejection similar to those in other liver transplant patients, serum transaminase levels were significantly higher in patients with GVHH syndrome. CONCLUSIONS: Erythrophagocytosis is a sensitive histological marker of GVHH syndrome. The severity of rejection and response to antirejection therapy should be monitored by markers other than transaminases in patients with GVHH syndrome. (Gastroenterology 1996 Jun;110(6):1891-6)     

Dexamethasone attenuates lipopolysaccharide-induced liver injury by downregulating glucocorticoid-induced tumor necrosis factor receptor ligand in Kupffer cells

Aim: Glucocorticoid‐induced tumor necrosis factor receptor ligand (GITRL) plays pro‐inflammatory roles in immune response. Thus, our aim was to assess if dexamethasone attenuates lipopolysaccharide (LPS)‐induced liver injury by affecting GITRL in Kupffer cells (KC). Methods: A BALB/c mouse model of liver injury was established by i.p. injecting with LPS (10 mg/kg) co‐treated with or without dexamethasone (3 mg/kg). Blood and liver samples were obtained for analysis of liver morphology, GITRL expression, hepatocellular function and cytokine levels at 24 h after injection. KC were isolated and challenged by LPS (1 µg/mL), with or without dexamethasone (10 µM) co‐treatment, or with GITRL siRNA pre‐transfection. The GITRL expression and cytokine levels were assayed at 24 h after challenge. Results: Dexamethasone treatment significantly improved the survival rate of endotoxemic mice (P < 0.05), whereas serum alanine aminotransferase, aspartate aminotransferase, tumor necrosis factor (TNF)‐α, interleukin (IL)‐6 and γ‐interferon levels were significantly decreased (P < 0.05, respectively). Concurrently, LPS‐induced hepatic tissue injury was attenuated as indicated by morphological analysis; and expression of GITRL in liver tissue and KC was downregulated (P < 0.05). Consistent with these in vivo experiments, inhibited expression of GITRL, TNF‐α and IL‐6 caused by dexamethasone treatment were also observed in LPS‐stimulated KC. The GITRL, TNF‐α and IL‐6 expression was also significantly inhibited by GITRL gene silencing. Conclusion: The TNF‐α and IL‐6 expression of LPS‐stimulated KC was inhibited by GITRL gene silencing. Dexamethasone attenuates LPS‐induced liver injury, at least proportionately, by downregulating GITRL in KC.