Kupffer cell function in chronic liver injury and after partial hepatectomy

Neuroimmunomodulation of adrenoblockers during liver cirrhosis: modulation of hepatic stellate cell activity

The sympathetic nervous system and the immune system are responsible for producing neurotransmitters and cytokines that interact by binding to receptors; due to this, there is communication between these systems. Liver immune cells and nerve fibres are systematically distributed in the liver, and the partial overlap of both patterns may favour interactions between certain elements. Dendritic cells are attached to fibroblasts, and nerve fibres are connected via the dendritic cell-fibroblast complex. Receptors for most neuroactive substances, such as catecholamines, have been discovered on dendritic cells. The sympathetic nervous system regulates hepatic fibrosis through sympathetic fibres and adrenaline from the adrenal glands through the blood. When there is liver damage, the sympathetic nervous system is activated locally and systemically through proinflammatory cytokines that induce the production of epinephrine and norepinephrine. These neurotransmitters bind to cells through α-adrenergic receptors, triggering a cellular response that secretes inflammatory factors that stimulate and activate hepatic stellate cells. Hepatic stellate cells are key in the fibrotic process. They initiate the overproduction of extracellular matrix components in an active state that progresses from fibrosis to liver cirrhosis. It has also been shown that they can be directly activated by norepinephrine. Alpha and beta adrenoblockers, such as carvedilol, prazosin, and doxazosin, have recently been used to reverse CCl₄-induced liver cirrhosis in rodent and murine models.KEY MESSAGESNeurotransmitters from the sympathetic nervous system activate and increase the proliferation of hepatic stellate cells.Hepatic fibrosis and cirrhosis treatment might depend on neurotransmitter and hepatic nervous system regulation.Strategies to reduce hepatic stellate cell activation and fibrosis are based on experimentation with α-adrenoblockers.

Hepatectomy-induced apoptotic extracellular vesicles stimulate neutrophils to secrete regenerative growth factors

BACKGROUND & AIMS

Surgical resection of the cancerous tissue represents one of the few curative treatment options for neoplastic liver disease. Such partial hepatectomy (PHx) induces hepatocyte hyperplasia, which restores liver function. PHx is associated with bacterial translocation, leading to an immediate immune response involving neutrophils and macrophages, which are indispensable for the priming phase of liver regeneration. Additionally, PHx induces longer-lasting intrahepatic apoptosis. Herein, we investigated the effect of apoptotic extracellular vesicles (aEVs) on neutrophil function and their role in this later phase of liver regeneration.

METHODS

A total of 124 patients undergoing PHx were included in this study. Blood levels of the apoptosis marker caspase-cleaved cytokeratin-18 (M30) and circulating aEVs were analyzed preoperatively and on the first and fifth postoperative days. Additionally, the in vitro effects of aEVs on the secretome, phenotype and functions of neutrophils were investigated.

RESULTS

Circulating aEVs increased at the first postoperative day and were associated with higher concentrations of M30, which was only observed in patients with complete liver recovery. Efferocytosis of aEVs by neutrophils induced an activated phenotype (CD11b^highCD16^highCD66b^highCD62L^low); however, classical inflammatory responses such as NETosis, respiratory burst, degranulation, or secretion of pro-inflammatory cytokines were not observed. Instead, efferocytosing neutrophils released various growth factors including fibroblast growth factor-2 and hepatocyte growth factor (HGF). Accordingly, we observed an increase of HGF-positive neutrophils after PHx and a correlation of plasma HGF with M30 levels.

CONCLUSIONS

These data suggest that the clearance of PHx-induced aEVs leads to a population of non-inflammatory but regenerative neutrophils, which may support human liver regeneration.

LAY SUMMARY

In this study, we show that the surgical removal of a diseased part of the liver triggers a specific type of programmed cell death in the residual liver tissue. This results in the release of vesicles from dying cells into the blood, where they are cleared by circulating immune cells. These respond by secreting hepatocyte growth factors that could potentially support the regeneration of the liver remnant.

NOX4 promotes Kupffer cell inflammatory response via ROS-NLRP3 to aggravate liver inflammatory injury in acute liver injury

AIM

This work aimed to investigate the mechanism of NOX4 in promoting Kupffer cells (KCs) activation and tissue inflammatory response in acute liver injury.

METHODS

Initially, the mouse KCs were cultured in vitro. Thereafter, the NOX4 overexpression plasmid was transfected into KCs to construct the overexpression cell line. Then, KCs inflammatory response was induced by LPS + Nigericin treatment. CCK-8 assay was performed to detect cell viability, flow cytometry (FCM) was conducted to measure cell apoptosis, enzyme-linked immunosorbent assay (ELISA) was performed to detect inflammatory factor levels in the culture medium, NLRP3 and ASC expression in cells was detected by immunofluorescence (IF) staining, and ROS expression was detected by the DCFH-DA probe. Furthermore, the expression levels of NLRP3, ASC and Caspase-1 proteins were detected by Western-Blot (WB) assay. Furthermore, cells were pre-treated with NOX inhibitor or NAC to suppress NOX4 expression or ROS production, aiming to further investigate the effect on KCs inflammatory response. In mouse experiments, the NOX4 knockdown mice and wild-type (WT) mice were adopted for carrying out experiments. The mouse model of ALI was constructed with LPS and D-GalN treatment. Thereafter, the changes in tissue samples were detected by H&E staining, NLRP3 expression was measured by histochemical staining, inflammatory factors in tissues were analyzed by ELISA, and the levels of NLRP3, ASC and Caspase-1 proteins in tissues were detected by WB assay.

RESULTS

LPS induced KCs inflammatory response. NOX4 overexpression decreased the mouse viability and increased the apoptosis rate. The levels of inflammatory factors were up-regulated in the culture medium. In addition, ROS were activated, and the positive cell number increased. Moreover, NOX4 promoted NLRP3 activation and significantly increased the expression of NLRP3 and ASC. Pretreatment with NOX4 inhibitor or NAC antagonized the effects of NOX4 and suppressed the KCs inflammatory response. In the mouse model, NOX4 knockdown significantly suppressed the activation and inflammatory response of microglial cells in tissues, reducing the NLRP3 expression in tissues.

CONCLUSION

NOX4 activates the NLRP3 inflammasome via ROS to promote inflammatory response in KCs and the release of inflammatory factors, suppressing NOX4 can improve ALI in mice, and NOX4 is promising as a new target for ALI treatment.

Particle Engineering of Innovative Nanoemulsion Designs to Modify the Accumulation in Female Sex Organs by Particle Size and Surface Charge

Particle engineering of nanosized drug delivery systems (DDS) can be used as a strategic tool to influence their pharmacokinetics after intravenous (i.v.) application by the targeted adaptation of their particle properties according to the needs at their site of action. This study aimed to investigate particle properties depending on patterns in the biodistribution profile to modify the accumulation in the female sex organs using tailor-made nanoemulsion designs and thereby to either increase therapeutic efficiency for ovarian dysfunctions and diseases or to decrease the side effects caused by unintended accumulation. Through the incorporation of the anionic phospholipid phosphatidylglycerol (PG) into the stabilizing macrogol 15 hydroxystearate (MHS) layer of the nanoemulsions droplets, it was possible to produce tailor-made nanoparticles with tunable particle size between 25 to 150 nm in diameter as well as tunable surface charges between −2 to nearly −30 mV zeta potential using a phase inversion-based process. Three chosen negatively surface-charged nanoemulsions of 50, 100, and 150 nm in diameter showed very low cellular toxicities on 3T3 and NHDF fibroblasts and merely interacted with the blood cells, but instead stayed inert in the plasma. In vivo and ex vivo fluorescence imaging of adult female mice i.v. injected with the negatively surface-charged nanoemulsions revealed a high accumulation depending on their particle size in the reticuloendothelial system (RES), being found in the liver and spleen with a mean portion of the average radiant efficiency (PARE) between 42–52%, or 8–10%, respectively. With increasing particle size, an accumulation in the heart was detected with a mean PARE up to 8%. These three negatively surface-charged nanoemulsions overcame the particle size-dependent accumulation in the female sex organs and accumulated equally with a small mean PARE of 5%, suitable to reduce the side effects caused by unintended accumulation while maintaining different biodistribution profiles. In contrast, previously investigated neutral surface-charged nanoemulsions accumulated with a mean PARE up to 10%, strongly dependent on their particle sizes, which is useful to improve the therapeutic efficacy for ovarian dysfunctions and diseases.

Ovarian Accumulation of Nanoemulsions: Impact of Mice Age and Particle Size

Nanotechnology in the field of drug delivery comes with great benefits due to the unique physicochemical properties of newly developed nanocarriers. However, they may come as well with severe toxicological side effects because of unwanted accumulation in organs outside of their targeted site of actions. Several studies showed an unintended accumulation of various nanocarriers in female sex organs, especially in the ovaries. Some led to inflammation, fibrosis, or decreasing follicle numbers. However, none of these studies investigated ovarian accumulation in context to both reproductive aging and particle size. Besides the influences of particle size, the biodistribution profile may be altered as well by reproductive aging because of reduced capacities of the reticuloendothelial system (RES), changes in sex steroid hormone levels as well as altering ovarian stromal blood flow. This systematic investigation of the biodistribution of intravenously (i.v) injected nanoemulsions revealed significant dependencies on the two parameters particle size and age starting from juvenile prepubescent to senescent mice. Using fluorescent in vivo and ex vivo imaging, prepubescent mice showed nearly no accumulation of nanoemulsion in their uteri and ovaries, but high accumulations in the organs of the RES liver and spleen independently of the particle size. In fertile adult mice, the accumulation increased significantly in the ovaries with an increased particle size of the nanoemulsions by nearly doubling the portion of the average radiant efficiency (PARE) to ~10% of the total measured signal of all excised organs. With reproductive aging and hence loss of fertility in senescent mice, the accumulation decreased again to moderate levels, again independently of the particle size. In conclusion, the ovarian accumulation of these nanocarriers depended on both the age plus the particle size during maturity.

Bioartificial liver attenuates intestinal mucosa injury and gut barrier dysfunction after major hepatectomy: Study in a porcine model

BACKGROUND

The aim of this study was to evaluate whether bioartificial liver support can attenuate gut mucosa injury in a porcine model of posthepatectomy liver dysfunction.

METHODS

Posthepatectomy liver failure was induced in pigs combining major (70%) liver resection and ischemia/reperfusion injury. An ischemic period of 150 minutes was followed by reperfusion for 24 hours. Animals were divided randomly into 2 groups: a control group (n = 6) that received standard critical care and a bioartificial liver support group (Hepat, n = 6) that were subjected to extracorporeal liver support for 6 hours during reperfusion. Intestinal mucosal injury, bacterial translocation, and endotoxin translocation were evaluated in all animals. Intestinal mucosa was also evaluated with markers of oxidative injury and immunohistochemical staining for caspase 3.

RESULTS

When compared with median values, the control group, animals in the Hepat group had a lesser intestinal mucosal injury score (4.0 [range:2.0-5.0] vs 1.0 [range:1.0-2.0]; P < .01), decreased bacterial translocation in the portal and the systemic circulation at 24 hours of reperfusion (P < .05), and decreased portal and systemic endotoxin levels at 24 hours (P < .05). At 24 hours after reperfusion, mucosal protein carbonyls and malondialdehyde levels were decreased in Hepat animals (0.57 nmol/mg [range:0.32-0.70] vs 0.33 nmol/mg [range:0.03-0.53] and 3.85 nmol/mg [range:3.01-6.43] vs 3.27 nmol/mg [range:1.46-3.55], respectively; P < .05). There was no difference in tissue caspase staining.

CONCLUSION

Bioartificial liver support seems to attenuate intestinal mucosal injury and gut barrier dysfunction after major hepatectomy.

Quantitative evaluation of the reticuloendothelial system function with dynamic MRI

PURPOSE

To evaluate the reticuloendothelial system (RES) function by real-time imaging blood clearance as well as hepatic uptake of superparamagnetic iron oxide nanoparticle (SPIO) using dynamic magnetic resonance imaging (MRI) with two-compartment pharmacokinetic modeling.

MATERIALS AND METHODS

Kinetics of blood clearance and hepatic accumulation were recorded in young adult male 01b74 athymic nude mice by dynamic T2* weighted MRI after the injection of different doses of SPIO nanoparticles (0.5, 3 or 10 mg Fe/kg). Association parameter, Kin, dissociation parameter, Kout, and elimination constant, Ke, derived from dynamic data with two-compartment model, were used to describe active binding to Kupffer cells and extrahepatic clearance. The clodrosome and liposome were utilized to deplete macrophages and block the RES function to evaluate the capability of the kinetic parameters for investigation of macrophage function and density.

RESULTS

The two-compartment model provided a good description for all data and showed a low sum squared residual for all mice (0.27±0.03). A lower Kin, a lower Kout and a lower Ke were found after clodrosome treatment, whereas a lower Kin, a higher Kout and a lower Ke were observed after liposome treatment in comparison to saline treatment (P<0.005).

CONCLUSION

Dynamic SPIO-enhanced MR imaging with two-compartment modeling can provide information on RES function on both a cell number and receptor function level.

(99m)Tc sulfur colloid and (99m)Tc mebrofenin hepatobiliary functional liver imaging in normal and diabetic rats

OBJECTIVES

To use (99m)Tc sulfur colloid ((99m)Tc-SC) and (99m)Tc mebrofenin ((99m)Tc-BrIDA) to study liver function in normal and diabetic rats.

MATERIALS AND METHODS

Radionuclide imaging was performed on 2 groups of rats, using (99m)Tc-SC for one group and (99m)Tc-BrIDA for the other (20 rats per group) before and after induction of diabetes mellitus (DM) using streptozotocin administration (55 mg/kg i.p.). Dynamic acquisition was obtained for 1 h after the injection of 37 MBq of radiotracer. For the (99m)Tc-SC group, organ/tissue uptake was determined by drawing regions of interest (ROI) over the heart, liver, spleen and also the whole body (WB). The ratio of the ROI of each organ to the WB ROI was calculated. For (99m)Tc-BrIDA, ratios of cumulative count rates in liver, liver parenchyma, biliary tree and abdomen ROI to a WB ROI were also calculated. Statistical analysis was performed to compare the ratios of organ/tissue uptake to WB uptake before and after DM induction using the paired t test.

RESULTS

(99m)Tc-SC uptake ratios (means ±SD) showed a lower liver-to-WB uptake ratio (0.75 ± 0.05) in the rats after DM induction compared to baseline (0.81 ± 0.06), while the cardiac blood pool showed higher uptake ratios in the rats after DM induction (p = 0.026). For (99m)Tc-BrIDA, there was no significant difference in radiotracer uptake ratios obtained from the rats before and after DM induction (p = 0.41).

CONCLUSION

Using functional liver imaging, there was a statistically significant decrease in the liver phagocytic/reticuloendothelial system function after DM induction, as evidenced by decreased (99m)Tc-SC liver uptake and increased blood pool compared to prediabetes, while the hepatobiliary function remained unchanged after DM induction using (99m)Tc-BrIDA imaging.

The adaptive response of the reticuloendothelial system to major liver resection in humans

OBJECTIVE

To evaluate the contribution of the liver to total circulatory reticuloendothelial system (RES) phagocytosis capacity in patients undergoing liver resection and to compare it with values in end-stage chronic liver disease.

SUMMARY BACKGROUND DATA

The mechanism whereby major liver resection is associated with a high incidence of infection is unknown. Significant impairment of RES phagocytosis has been described in liver failure, rendering such patients susceptible to infection; and we hypothesized that similar impairment might occur following major liver resection.

METHODS

A prospective study was conducted in which Tc-albumin microspheres blood clearance served as a parameter for RES phagocytosis and was studied together with indocyanine green blood clearance, actual liver volume measured by three-dimensional image analysis, and a clinical score of hepatic dysfunction in 17 patients undergoing liver resection and in 8 patients with end-stage chronic liver disease assessed for liver transplantation.

RESULTS

When expressed relative to volume unit of residual liver, microspheres clearance increased significantly in the immediate postoperative period (day 1) following major (0.009% versus 0.022% min(-1) mL(-1), P < 0.001), but not minor liver resection. In contrast, the absolute rate of microsphere clearance decreased following major resection (15% min(-1) versus 10% min(-1), P < 0.001) and was comparable with the rate observed in end-stage chronic liver disease (9% min(-1)). This decrease in circulatory microspheres clearance after resection paralleled a decrease in indocyanine green clearance (R2 = 0.511, P = 0.006), and there was a trend for those with moderate liver dysfunction to have lower microspheres clearance rates (P = 0.068).

CONCLUSION

Preservation of a minimum volume of functioning liver is a prerequisite for adequate RES phagocytosis capacity, and failure of this system may predispose patients undergoing major liver resection to infection as observed in clinical studies.

Protective effect of selenium-enriched lactobacillus on CCl4-induced liver injury in mice and its possible mechanisms

AIM: To study the protective effects and mechanisms of Se-enriched lactobacillus on liver injury caused by carbon tetrachloride (CCl₄) in mice.

METHODS: Seventy-two ICR mice were randomly divided into four groups: normal group, CCl₄-induced model group, low Se-enriched lactobacillus treatment group (L-Se group), and high Se-enriched lactobacillus treatment group (H-Se group). During a 3-wk experimental period, the common complete diet was orally provided daily for normal group and model group, and the mice in L-Se and H-Se groups were given a diet with 2 and 4 mg of organoselenium from Se-enriched lactobacillus per kg feed, respectively. From the 2nd wk of experiment, the model group, L-Se group, and H-Se group received abdominal cavity injection of olive oil solution containing 500 mL/L CCl₄ (0.07 mL/100 g body mass) to induce liver injury, and the normal group was given olive oil on every other day for over 2 wk. In the first 2 wk post injection with CCl₄, mice in each group were killed. The specimens of blood, liver tissue, and macrophages in abdominal cavity fluid were taken. Then the activities of the following liver tissue injury-associated enzymes including glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) as well as malondialdehyde (MDA) content were assayed. Changes of phagocytic rate and phagocytic index in macrophages were observed with Wright-Giemsa stain. Plasma TNF-α level was measured by radioimmunoassay. The level of intracellular free Ca²⁺ ([Ca²⁺]i) in hepatocytes was detected under a laser scanning confocal microscope.

RESULTS: During the entire experimental period, the AST and ALT activities in liver were greatly enhanced by CCl₄ and completely blunted by both low and high doses of Se-enriched lactobacillus. The Se-enriched lactobacillus-protected liver homogenate GSH-Px and SOD activities were higher or significantly higher than those in model group and were close to those in normal group. CCl₄ significantly increased MDA content in liver homogenates, while administration of Se-enriched lactobacillus prevented MDA elevation. Phagocytic rate and phagocytic index of macro-phages decreased after CCl₄ treatment compared to those in normal control, but they were dramatically rescued by Se-enriched lactobacillus, showing a greatly higher phagocytic function compared to model group. CCl₄ could significantly elevate plasma TNF-α and hepatocyte [Ca²⁺]ilevel, which were also obviously prevented by Se-enriched lactobacillus.

CONCLUSION: Se-enriched lactobacillus can intervene in CCl₄-induced liver injury in mice by enhancing macrophage function activity to keep normal and beneficial effects, elevating antioxidant-enzyme activities and reducing lipid peroxidation reaction, inhibiting excessive release of TNF-α, preventing the dramatic elevation of [Ca²⁺]i in hepatocytes.

Mayak worker study: an improved biokinetic model for reconstructing doses from internally deposited plutonium

The plutonium production facility known as the Mayak Production Association was put into operation in June 1948. A high incidence of cancer in the Mayak workers has been related to the level of exposure to plutonium, but uncertainties in tissue doses have hampered development of dose-risk relationships. As part of an effort to improve dose estimates for these workers, the systemic biokinetic model for plutonium currently recommended by the International Commission on Radiological Protection (ICRP) has been modified to reflect recently developed data and facilitate interpretation of case-specific information. This paper describes the proposed model and discusses its implications for dose reconstruction for the Mayak workers.

Early-enhancing nonneoplastic lesions on gadolinium-enhanced magnetic resonance imaging of the liver following partial hepatectomy

PURPOSE

To assess the frequency, imaging findings, and significance of early-enhancing nonneoplastic (EN) lesions with gadolinium-enhanced magnetic resonance imaging (MRI) of the liver following partial hepatectomy.

MATERIALS AND METHODS

We retrospectively reviewed MR images after partial hepatectomy in 30 patients. Postoperative MRI was performed in 1-12 months (mean, 3.7 months) after partial hepatectomy. We defined the EN lesion as a lesion that was ill defined; irregular, wedge shaped, or serpiginous; located along the liver edge; not visible on unenhanced MR images; did not appear hypointense on portal venous- or equilibrium-phase images; or a combination of those imaging findings.

RESULTS

A total of 39 EN lesions (size range, 5-60 mm; mean, 25.2 mm) in 19 patients and 17 recurrent tumors (size range, 5-50 mm; mean, 16.8 mm) in 10 patients newly appeared after partial hepatectomy. The EN lesions were diagnosed as pseudolesions by the second postoperative follow-up MRI in 17 patients or contrast-enhanced computed tomography (CT) in two. A total of 13 EN lesions (33%) were located along the liver edge and 20 (51%) were adjacent to the resected area. The shape was circular in 11 (28%), oval in three (8%), irregular in 11 (28%), wedge shaped in five (13%), and serpiginous in nine (23%). No EN lesion showed hypointensity on gadolinium-enhanced portal venous-phase or equilibrium-phase images. A total of 14 EN lesions (36%) showed slight hyperintensity on T2-weighted images. The confidence levels for malignancy probability assigned by blinded radiologists were lower with EN lesions than with recurrent tumors (P < 0.001).

CONCLUSION

EN lesions are frequently seen in MRI following partial hepatectomy, and occasionally are slightly hyperintense on T2-weighted images, mimicking malignant tumors. However, most EN lesions can be correctly diagnosed with MRI findings.

Superparamagnetic iron oxide-mediated hepatic signal intensity change in patients with and without cirrhosis: pulse sequence effects and Kupffer cell function

PURPOSE

To analyze superparamagnetic iron oxide (SPIO)-mediated hepatic signal intensity change in cirrhotic and noncirrhotic liver and to investigate the relationship between pulse sequence effects in SPIO-enhanced magnetic resonance (MR) imaging for hepatic cirrhosis.

MATERIALS AND METHODS

Twelve patients with and 12 patients without cirrhosis underwent T2-weighted fast spin-echo, T2*-weighted gradient-echo (GRE), and T1-weighted GRE MR imaging before and twice (early and late phase) after SPIO administration. To assess the effect of SPIO, postcontrast relative signal-to-noise ratio (SNR) changes were statistically analyzed with repeated measurements analysis of variance for each pulse sequence.

RESULTS

No interaction was shown between groups and data time points for any pulse sequence. There was no significant difference in mean hepatic relative SNR change on T2-weighted fast spin-echo images between the cirrhotic group and noncirrhotic group (-38.6% and -40.7%, early phase; -42.2% and -49.6%, late phase, respectively). For GRE images, statistically significant differences in mean hepatic relative SNR change were found between the cirrhotic group and noncirrhotic group (-14.2% and -44.5%, early phase; -28.5% and -56.4%, late phase on T2*-weighted GRE images (P <.001); 31.8% and 12.9%, early phase; 23.8% and 2.2%, late phase on T1-weighted GRE images (P <.05), respectively.

CONCLUSION

Decreased overall phagocytic activity in cirrhotic liver is more likely due to Kupffer cell dysfunction than to Kupffer cell depletion, since magnetic susceptibility effects on T2*-weighted GRE images depend on intracellular SPIO cluster size.

Endotoxin clearance and its relation to hepatic and renal disturbances in rats with liver cirrhosis

BACKGROUND/AIMS

Little is known about endotoxin clearance and secretion of cytokines from macrophages in liver cirrhosis. The aims of this study were to investigate the relationship of endotoxin clearance and release of tumor necrosis factor alpha by various macrophages to hepatic and renal disturbances in liver cirrhosis.

METHODS

Male Sprague-Dawley rats were given 0.04% thioacetamide orally for 6 or 12 months. The organ distribution of infused [3H]-endotoxin (10 microg/kg b.w.) was analyzed at 30 min or at 24 h. Uptake of [3H]-endotoxin and secretion of tumor necrosis factor alpha by Kupffer cells, splenic macrophages and peripheral blood monocytes (1 x 10(4) cells/ml) from cirrhotic and control rats were determined.

RESULTS

In cirrhotic rats, more endotoxin was left in the body and more endotoxin accumulated in the spleen and kidney, and thus was related to elevation of serum total bilirubin, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, creatinine and tumor necrosis factor alpha. Endotoxin uptake and tumor necrosis factor alpha release by the Kupffer cells were decreased and those by the splenic macrophages and peripheral blood monocytes were increased in cirrhotic rats.

CONCLUSIONS

In liver cirrhosis, impaired clearance of endotoxin together with increased secretion of tumor necrosis factor alpha by extrahepatic macrophages may play an important role in the progression of hepatic and renal disturbances.

Enhanced tumor detection in the presence of liver cirrhosis: experimental study on the diagnostic value of a superparamagnetic iron oxide MR imaging contrast agent (NSR 0430)

The purpose of this study was to determine the diagnostic value of the superparamagnetic iron oxide NSR 0430 for the detection of focal liver lesions in the presence of advanced cirrhosis. Cirrhosis and growth of cholangiofibromas were induced in 22 rats by administration of thioacetamide. Sixteen non-cirrhotic animals served as controls. T1 and T2 relaxation times of liver and tumor tissue of 12 animals were measured spectroscopically. In 10 animals in vivo MRI was performed before and 1 hour after contrast administration, and then the tumor-to-liver contrast-to-noise ratio (CNR) was calculated. All specimens were evaluated histologically. After contrast administration, T1 and T2 values of liver tissue showed a significant decrease of 18% (P = 0.01) and 31% (P = 0.009), respectively, whereas relaxation times of tumor tissue did not change. On precontrast turbo spin-echo images, 40 tumors could be identified; after contrast administration, 95 lesions were visible. CNR increased significantly after contrast administration by 297% at a TE of 50 msec and by 254% at a TE of 90 msec. In conclusion, our in vitro and in vivo results demonstrate that administration of NSR 0430 substantially improves liver-to-tumor CNR and lesion detection on T2-weighted magnetic resonance images even in the presence of severe cirrhosis.

Hepatic haemodynamics and reticuloendothelial function in the rat in response to chronic ethanol administration

This study investigated the effects of chronic ethanol intake on hepatic haemodynamics and reticuloendothelial system function in the rat. Comparisons were also made with blood flow to pancreas, kidney, spleen, lung and skin. Male Wistar rats, approximately 0.15 kg initial body weight, were fed a diet containing 35% of the total calories as ethanol. Controls were pair-fed identical amounts of the same diet in which ethanol was replaced by isocaloric glucose. The hepatic perfusion index and reticuloendothelial function was determined with [(99m) Tc]-labelled sulphur colloid [(99m) Tc]-SC) and blood flow with radiolabelled microspheres under anaesthesia. After 4-5 weeks the weights of liver and skin of alcohol fed rats decreased by 10% (p= 0.040) and 23% (p= 0.024), respectively, compared to controls and there was a small increase in kidney weight (15%, p = 0.001). Blood flow to liver, pancreas, kidney, spleen, lung and skin was not altered significantly by chronic alcohol administration, irrespective of whether the data were expressed as a percentage of cardiac output, blood flow per minute per organ or blood flow per minute per g tissue weight (p > 0.113 in all instances). However, there was a significant increase in splenic reticuloendothelial system activity (+ 121%, p = 0.018). Hepatic reticuloendothelial system activity was also increased (+ 22%, p = 0.061). Chronic alcohol administration resulted in significant increases in portal pressure (+ 55%, p = 0.042) and portal venous resistance (+ 66%, p = 0.001), but portal venous inflow and hepatic perfusion index were not altered compared to controls The results of this study indicated that chronic alcohol administration did not alter visceral blood flow significantly, but did increase portal pressure, portal vascular resistance and reticuloendothelial system activity.