Impaired superoxide anion, platelet-activating factor, and leukotriene B4 synthesis by neutrophils in cirrhosis

Circulating neutrophil anti-pathogen dysfunction in cirrhosis

Neutrophils are the largest population of leucocytes and are among the first cells of the innate immune system to fight against intruding pathogens. In patients with cirrhosis, neutrophils exhibit altered functionality, including changes in phagocytic ability, bacterial killing, chemotaxis, degranulation, reactive oxygen species production and NET (neutrophil extracellular trap) formation. This results in their inability to mount an adequate antibacterial response and protect the individual from infection. Prognosis and survival in patients with cirrhosis are greatly influenced by the development of infectious complications. Multidrug-resistant bacterial infections in patients with cirrhosis are currently a growing problem worldwide; therefore, alternative methods for the prevention and treatment of bacterial infections in cirrhosis are urgently needed. The prevention and treatment of neutrophil dysfunction could be a potential way to protect patients from bacterial infections. However, the reasons for changes in neutrophil function in cirrhosis are still not completely understood, which limits the development of efficient therapeutic strategies. Both cellular and serum factors have been proposed to contribute to the functional impairment of neutrophils. Herein, we review the current knowledge on features and proposed causes of neutrophil dysfunction in cirrhosis, with a focus on current knowledge gaps and limitations, as well as opportunities for future investigations in this field.

Mechanisms of immunity in acutely decompensated cirrhosis and acute-on-chronic liver failure

The identification of systemic inflammation (SI) as a central player in the orchestration of acute-on-chronic liver failure (ACLF) has opened new avenues for the understanding of the pathophysiological mechanisms underlying this disease condition. ACLF, which develops in patients with acute decompensation of cirrhosis, is characterized by single or multiple organ failure and high risk of short-term (28-day) mortality. Its poor outcome is closely associated with the severity of the systemic inflammatory response. In this review, we describe the key features of SI in patients with acutely decompensated cirrhosis and ACLF, including the presence of a high blood white cell count and increased levels of inflammatory mediators in systemic circulation. We also discuss the main triggers (i.e. pathogen- and damage-associated molecular patterns), the cell effectors (i.e. neutrophils, monocytes and lymphocytes), the humoral mediators (acute phase proteins, cytokines, chemokines, growth factors and bioactive lipid mediators) and the factors that influence the systemic inflammatory response that drive organ failure and mortality in ACLF. The role of immunological exhaustion and/or immunoparalysis in the context of exacerbated inflammatory responses that predispose ACLF patients to secondary infections and re-escalation of end-organ dysfunction and mortality are also reviewed. Finally, several new potential immunogenic therapeutic targets are debated.

Computerized Tomography-Guided Paracentesis: An Effective Alternative to Bedside Paracentesis?

Background

Ascites remains the most common cause of hospitalization among patients with decompensated cirrhosis. Paracentesis is a relatively safe procedure with low complication rates. Computerized tomography (CT)-guided therapeutic paracentesis could be a safe and effective alternative to unaided or aided (ultrasonogram-guided) bedside paracentesis. In this retrospective study, we aimed to compare the efficacy, safety, and cost-effectiveness of CT-guided paracentesis with bedside paracentesis.

Methods

The period of study was from 2002 to 2012. All patients with cirrhosis who underwent therapeutic paracentesis were included in the study. These patients were divided into two groups. Group I consisted of patients who underwent CT-guided pigtail catheter insertion with ascitic fluid drainage. Group II consisted of patients who underwent beside therapeutic paracentesis after localization of fluid either by physical examination or sonographic localization. We measured the efficacy of CT-guided paracentesis and bedside paracentesis in terms of volume of fluid removed, length of stay, discharge doses of diuretics (spironolactone and furosemide) and number of days to readmission for symptomatic ascites. We also computed the cost-effectiveness of CT-guided therapeutic paracentesis when compared to a bedside procedure. Fischer exact test was used to analyze the distribution of categorical data and unpaired t-test was used for comparison of means.

Results

There were a total of 546 unique patients with diagnosed cirrhosis who were admitted to the hospital with symptomatic ascites and underwent therapeutic paracentesis. Two hundred and forty-seven patients underwent CT-guided paracentesis, while 272 patients underwent bedside paracentesis. There was significant inverse correlation between the amount of ascitic fluid removed and total length of stay in the hospital. We found that the volume of fluid removed via a CT-guided pigtail insertion and drainage (2.72 ± 2.02 L) is significantly higher when compared to fluid removed via bedside paracentesis (1.94 ± 1.69). We also found that the interval time period between two successive therapeutic paracenteses was significantly longer for CT group (106.56 ± 75.2 days) when compared to the bedside group (25.57 ± 7.68 days).

Conclusion

CT-guided paracentesis with pigtail catheter insertion and drainage is a clinically effective, cheap and safe alternative to conventional bedside paracentesis.

Increased Risks of Spontaneous Bacterial Peritonitis and Interstitial Lung Disease in Primary Biliary Cirrhosis Patients With Concomitant Sjögren Syndrome

The incidence of Sjögren syndrome (SS) in primary biliary cirrhosis (PBC) patients is high. The influence of SS on the clinical outcomes of PBC patients, however, remains unclear. Our study retrospectively collected data on PBC-only patients and PBC patients with concomitant SS (PBC-SS) to compare the clinical differences of long-term outcomes between them.A total of 183 patients were diagnosed with PBC from January 1999 to December 2014 at our hospital. Of these, the authors excluded patients with diabetes, hypertension, advanced liver cirrhosis at initial diagnosis of PBC (Child-Turcotte-Pugh classification score of ≥7) and other liver diseases (ie, alcoholic liver disease, alpha-antitrypsin deficiency, viral hepatitis, and primary sclerosing cholangitis), and autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. Of the remaining 125 patients, 77 (61.6%) were PBC-only and 48 (38.4%) were PBC-SS patients.The mean follow-up duration was 8.76 years. During the observation period, the incidence of interstitial lung disease was higher in the PBC-SS group than in the PBC-only group (P = 0.005). The occurrence of spontaneous bacterial peritonitis was significantly different in PBC-SS patients than in PBC-only patients (P = 0.002). The overall survival was lower in PBC-SS patients than in PBC-only patients (P = 0.033). Although the incidence of hepatocellular carcinoma, end-stage renal disease, variceal bleeding, and hypothyroidism were all higher in the PBC-SS group than in the PBC-only group, the differences were not significant.Our study suggests that PBC-SS patients have a higher risk of developing interstitial lung disease and spontaneous bacterial peritonitis and have a poor prognosis. Aggressive surveillance of thyroid and pulmonary functions should therefore be performed in these patients.

Immune dysfunction and infections in patients with cirrhosis

Patients with cirrhosis are immunocompromised and susceptible to infections. Although detection and treatment of spontaneous bacterial peritonitis (SBP) have improved, overall survival rates have not increased greatly in recent decades-infection still increases mortality 4-fold among patients with cirrhosis. Hospitalized patients with cirrhosis have the highest risk of developing infections, especially patients with gastrointestinal (GI) hemorrhage. Bacterial infections occur in 32% to 34% of patients with cirrhosis who are admitted to the hospital and 45% of patients with GI hemorrhage. These rates are much higher than the overall rate of infection in hospitalized patients (5%-7%). The most common are SBP (25% of infections), urinary tract infection (20%), and pneumonia (15%). Bacterial overgrowth and translocation from the GI tract are important steps in the pathogenesis of SBP and bacteremia-these processes increase levels of endotoxins and cytokines that induce the inflammatory response and can lead to septic shock, multiorgan dysfunction, and death. A number of other bacterial and fungal pathogens are more common and virulent in patients with cirrhosis than in the overall population. We review the pathogenesis of infections in these patients, along with diagnostic and management strategies.

Platelet-activating factor involvement in thioacetamide-induced experimental liver fibrosis and cirrhosis

Platelet-activating factor (PAF) is a potent lipid inflammatory mediator acting on cells through its specific receptor. Plasma PAF-acetylhydrolase (PAF-AH) is the main enzyme that inactivates PAF in blood, participating in its homeostasis. The objective of this study was to investigate the involvement of PAF in the liver fibrotic process using an experimental animal model. Liver fibrosis was induced in adult male Wistar rats by administration of thioacetamide (TAA) in drinking water (300 mg/l) for three months. The animals were sacrificed at time 0 (control group) and after 1, 2, and 3 months. PAF levels in liver and blood and PAF-AH activity in plasma were determined. Liver histopathological examination was also performed. TAA administration resulted in progressively increased liver fibrosis, leading finally to the formation of cirrhotic nodules in the liver. Throughout the experiment PAF levels in liver tissue remained stable. "Total" ("free" plus "bound") PAF levels in blood decreased, reaching statistically significant differences in the first and third months compared with the control group (P < 0.05). "Free" PAF levels in blood were higher at one month (P < 0.05) and decreased gradually thereafter. In all treated groups, "bound" PAF levels in blood decreased whereas plasma PAF-AH activity increased (P < 0.05) compared with the control group. Our data indicated alterations of PAF levels in blood and PAF-AH activity during fibrosis induction, implicating participation of PAF in the liver fibrotic process.

Bacterial translocation increases phagocytic activity of polymorphonuclear leucocytes in portal hypertension: priming independent of liver cirrhosis

AIM

Bacterial translocation (BT) to mesenteric lymph nodes (MLN) in cirrhosis has been linked to impaired host defence. Phagocytosis by polymorphonuclear leucocytes (PMNLs) is the primary event in the killing of bacteria but has not been investigated in relation to the presence of BT.

METHODS

Mesenteric lymph nodes were harvested sterile and assessed for BT by culture techniques. Study groups included ascitic cirrhotic rats (LC), healthy controls (Con) as well as portal-vein-ligated (PVL) rats 2 days (acute PVL with and without norfloxacin) or 3 weeks after surgery (chronic PVL). PMNLs were isolated from systemic blood and the capacity to phagocytose opsonized Escherichia coli was evaluated by FACS analysis.

RESULTS

No BT was observed in Con and chronic PVL animals but 11/20 LC (55%) and six out of six acute PVL (100%) presented with BT. In the presence of BT, PMNL from PVL as well as LC rats showed significantly increased phagocytic activity as compared with controls. In contrast, PMNL from animals without BT, whether PVL or LC, exhibited phagocytic activity similar to those from control rats. The number of PMNLs involved in the phagocytic process was significantly increased only in portal-hypertensive rats with but not without BT as compared with controls. Norfloxacin did prevent BT in acute PVL animals, thereby correcting the increase in phagocytic capacity in PMNL.

CONCLUSIONS

Cirrhosis per se is not associated with alterations of the phagocytic capacity of PMNL. The occurrence of BT, however, increases the phagocytic capacity of PMNL, being observed likewise in prehepatic portal hypertension, indicating an in vivo'priming' of PMNL by BT independent of cirrhosis.

Decreased leukocyte recruitment in the mesenteric microcirculation of rats with cirrhosis is partially restored by treatment with peginterferon: an in vivo study

BACKGROUND/AIMS

Patients with liver cirrhosis are predisposed to develop bacterial infections. An essential process in inflammatory responses is the recruitment of circulating leukocytes through the activation of adhesion molecules. Interferon-alpha2a is a cytokine reported to influence the expression of adhesion molecules. We investigated the effect of peginterferon-alpha2a (PegIFN-alpha(2a)) in vivo on the leukocyte recruitment in the mesenteric microcirculation of cirrhotic rats after lipopolysaccharide exposure.

METHODS

Leukocyte rolling, adhesion and extravasation were visualized by intravital microscopy in sham-operated and common bile duct ligated (CBDL) rats. PegIFN-alpha(2a) was administered to influence leukocyte recruitment. Endothelial P-selectin, E-selectin and ICAM-1 expression were studied by immunohistochemistry.

RESULTS

CBDL placebo rats showed significantly impaired rolling, adhesion and extravasation of leukocytes compared to Sham-operated placebo rats. Endothelial P-selectin, E-selectin and ICAM-1 expressions in CBDL placebo rats were significantly reduced compared to Sham-operated placebo rats. PegIFN-alpha(2a) 18 microg normalized number of rolling leukocytes in CBDL rats, without influencing on adhering and extravasated leukocytes. PegIFN-alpha(2a) upregulates the expression of P-selectin and E-selectin in CBDL rats, but ICAM-1 expression remained significantly lower than in Sham rats.

CONCLUSIONS

Leukocyte recruitment is significantly impaired in the mesenteric microcirculation of cirrhotic rats. This deficiency appears to result from a reduced endothelial P-selectin, E-selectin and ICAM-1 expression. Peginterferon-alpha(2a) treatment normalizes rolling of leukocytes in cirrhotic rats by upregulation of P-selectin and E-selectin expressions, but has no influence on adhesion and extravasation possibly due to the absence of effect on ICAM-1 expression.

Platelet-activating factor in liver injury: A relational scope

The hepatocyte, the main cellular component of the liver, exhibits variable susceptibility to different types of injury induced by endogenous or exogenous factors. Hepatocellular dysfunction or death and regeneration are dependent upon the complicated interactions between numerous biologically active molecules. Platelet-activating factor (PAF) seems to play a pivotal role as the key mediator of liver injury in the clinical and experimental setting, as implied by the beneficial effects of its receptor antagonists. A comprehensive up-to-date overview of the specific functional and regulatory properties of PAF in conditions associated with liver injury is attempted in this review.

Hemorheology in patients with liver cirrhosis: special emphasis on its relation to severity of esophageal variceal bleeding

BACKGROUND

Patients with decreased blood viscosity are supposed to have a higher risk of bleeding and increased severity of bleeding (severity of bleeding proportional to transmural pressure x area of variceal tear/blood viscosity). However, the hemorheological factors have never been assessed in patients with esophageal variceal bleeding. Therefore, the purpose of the present study was to examine the hemorheological factors in liver cirrhotic patients with special emphasis on the outcome of variceal bleeding.

METHODS

Forty-two liver cirrhosis patients with variceal bleeding and another 44 matched patients without bleeding were enrolled. The hemorheological and hemostatic factors of their peripheral blood were examined. The clinical course was under careful surveillance.

RESULTS

Patients with poor hepatic reserve (Child B + C vs A) had lower whole blood viscosity (4.34 +/- 0.56 mPa.s vs 5.06 +/- 1.35 mPa.s, P < 0.05), lower hematocrit levels (32.86 +/- 5.97% vs 36.62 +/- 5.44%, P < 0.05), lower platelet counts (79.7 +/- 47.6 x 10(3)/mL vs 108.0 +/- 71.2 x 10(3)/mL, P < 0.05) and prolonged prothrombin time (2.88 +/- 2.33 s vs 1.27 +/- 1.37 s, P < 0.05). Patients with bleeding (vs non-bleeding group) had lower hematocrit levels (31.44 +/- 5.75% vs 36.57 +/- 5.19%, P < 0.01) and lower fibrinogen levels (226.7 +/- 92.7 mg/dL vs 286.4 +/- 111.8 mg/dL, P < 0.05). Patients with bleeding with shock had worse liver cirrhosis (Child A/B/C = 0/5/4 vs 11/18/4, P < 0.05), lower whole blood viscosity (4.01 +/- 0.17 mPa.s vs 4.57 +/- 0.76 mPa.s, P < 0.05), reduced erythrocyte aggregability (2.94 +/- 0.41 vs 3.54 +/- 0.61, P < 0.001), and lower platelet counts (56.22 +/- 17.05 x 10(3)/mL vs 88.87 +/- 38.12 x 10(3)/mL, P < 0.001). The Child-Pugh grade and erythrocyte aggregability were two independent factors associated with bleeding shock.

CONCLUSIONS

Whole blood viscosity, hematocrit levels and platelet counts were lower in patients with advanced liver cirrhosis. Advanced liver cirrhosis and reduced erythrocyte aggregability were independent factors for hypovolemic shock in cirrhotic patients with esophageal variceal bleeding. However, the causal relationship between hemorheology and bleeding needs to be clarified in further studies.

Effect of hepatic iron concentration reduction on hepatic fibrosis and damage in rats with cholestatic liver disease

AIM: To assess the effect of iron reduction after phlebotomy in rats with “normal” hepatic iron concentration (HIC) on the progression of hepatic fibrosis, as a result of bile duct ligation (BDL).

METHODS: Rats underwent phlebotomy before or after sham operation or BDL. Animals undergone only BDL or sham operation served as controls. Two weeks after surgery, indices of hepatic damage and fibrosis were evaluated.

RESULTS: Phlebotomy lowered HIC. Phlebotomy after BDL was associated with body weight increase, lower hepatic weight, less portal hypertension, less periportal necrosis, less portal inflammation, lower hepatic activity index score and higher albumin levels. On the other hand, phlebotomy before BDL was associated with body weight decrease and hepatic activity index score increase. Phlebotomy after sham operation was not associated with any hepatic or systemic adverse effects.

CONCLUSION: Reduction of HIC after induction of liver damage may have beneficial effects in BDL rats. However, iron deficiency could induce impairment of liver function and may make the liver more susceptible to insults like BDL.

Opsonophagocytic dysfunction in patients with liver cirrhosis and low responses to tumor necrosis factor-alpha and lipopolysaccharide in patients' blood

To evaluate their defense level against bacterial infection of patients with liver cirrhosis, we compared the luminol-dependent chemiluminescence (CL) response of peripheral blood from 40 patients with that from 40 healthy volunteers. Small quantities of heparinized whole blood (100 microl; final dilution, 1:10) were used for phagocytes, and CL was measured on addition of nonopsonized zymosan or Escherichia coli without special opsonization. Whole blood CL in cirrhotic patients was significantly lower than that in the healthy controls. The incidence of lower CL response in patients increased as disease stage advanced. Polymorphonuclear leukocytes (PMN) from cirrhotic patients exhibited a slightly lower CL response than those from controls, but this was not statistically significant. In contrast, the CL response of monocytes in patients was significantly lower than that of controls. The opsonizing capacity of the patients' sera and ascitic fluid was also decreased. In fact, the levels of opsonins such as complement in the patients' sera and both immunoglobulins and complement in the ascitic fluids were found to be lower in cirrhotic patients. On the basis of these findings, defect of opsonophagocytic function seems to participate in the increased susceptibility to infection in cirrhotic patients. Furthermore, whole blood CL induced by nonopsonized zymosan at the onset of relatively severe bacterial infections such as sepsis, pneumonia, or spontaneous bacterial infection was less augmented in the blood of cirrhotic patients than that in noncirrhotic patients. To clarify the reason why whole blood exhibits a lower CL response in the acute phase of bacterial infections, we investigated the priming effects of lipopolysaccharide (LPS) or tumor necrosis factor-alpha (TNF-alpha), well-known CL activators, on the CL response of whole blood obtained from cirrhotic patients in comparison with that from healthy persons. The priming effects were significantly decreased in patients' blood when compared with that of healthy persons. These low responses of patients' blood to LPS or TNF-alpha support our finding that phagocytes are not fully activated when gram-negative bacterial infections occur.

Increased apoptosis dependent on caspase-3 activity in polymorphonuclear leukocytes from patients with cirrhosis and ascites

BACKGROUND/AIMS

Patients with decompensated cirrhosis are prone to develop neutropenia. Although hypersplenism and increased clearance of polymorphonuclear leukocytes (PMN) in the spleen are thought to contribute to neutropenia in these patients, other factors cannot be excluded. The aim of the current study was to investigate whether the presence of increased PMN apoptosis could also contribute to the appearance of neutropenia in these patients.

METHODS

PMN were isolated by Ficoll-Hypaque gradient centrifugation from 17 patients with decompensated cirrhosis (CH group) and 13 patients with compensated chronic liver disease (CT group). PMN were incubated in RPMI 1640 medium at 37 degrees C in a 5% CO(2) atmosphere and viability and frequency of apoptosis were evaluated after 0, 10, 20 and 40 h of culture. Viability was determined by the MTT assay and apoptosis by microscopic examination of cell morphology (Diff-Quik staining), DNA fragmentation by agarose gel electrophoresis (DNA laddering) and caspase-3 activity by DVDE-p-nitroanilide cleavage.

RESULTS

Compared to CT patients, PMN isolated from CH patients exhibited a decreased PMN viability and a marked accelerated apoptosis as revealed by an increased number of condensed nuclei, increased DNA laddering and significantly higher caspase-3 activity.

CONCLUSIONS

These findings indicate that shortening of PMN survival via apoptosis may explain in part the neutropenia present in decompensated cirrhotic patients with ascites, thus favoring the development of bacterial infections in these patients.

Deficient phospholipase C activity in blood polimorphonuclear neutrophils from patients with liver cirrhosis

BACKGROUND/AIMS

Circulating neutrophils from cirrhotic patients have a reduced capacity to generate superoxide anion (O(2)(-)), which might contribute to frequent bacterial infections in these patients. We studied the signal transduction pathways involved in the generation of O(2)(-) in neutrophils from 98 cirrhotic patients and 46 healthy controls.

METHODS

We measured O(2)(-) production in neutrophils induced by fMLP, opsonized zymosan, TNF alpha, NaF, AlF(4)(-), A23187 and phorbol myristate acetate. Furthermore, we measured phospholipase C activity in neutrophils from healthy controls and end-stage cirrhotic patients.

RESULTS

O(2)(-) production was decreased in neutrophils from patients in response to fMLP, opsonized zymosan and TNF alpha. Likewise, response of these cells to G-protein stimulation by fluorides was also decreased. These reduced responses correlated significantly with the degree of liver dysfunction. On the contrary, neutrophils from patients responded normally to A23187 and phorbol esters stimulation indicating that Ca(2+)- and PKC-dependent pathways are intact in these cells. Finally, phospholipase C activity was markedly reduced in neutrophils from end-stage liver cirrhosis.

CONCLUSIONS

These data confirm that O(2)(-) generation by neutrophils is decreased in patients with cirrhosis, particularly in those with more severe liver dysfunction, and suggest that this defect involves phosphatidylinositol specific phospholipase C activity.

Experimental colitis in rats with portal hypertension and liver disease

Within the colonic mucosa of rats with portal hypertension and liver cirrhosis, there is an increased generation of inflammatory mediators, such as leukotriene B4 and endothelin-1, and increased generation of nitric oxide. Nitric oxide overproduction may induce tissue injury. This study was undertaken to assess whether the colonic mucosa of rats with portal hypertension and liver disease have increased susceptibility to damage by noxious agents. In this study, acetic acid colitis was induced in rats with portal vein ligation and in control groups, and iodoacetamide colitis was induced in rats with partial portal vein ligation and cirrhosis due to bile duct ligation and in control groups. Rats with acetic acid colitis and those with iodoacetamide-induced colitis were studied 24 and 72 hours, respectively, after induction of colitis. Portal hypertension alone and portal hypertension with cirrhosis were present in the portal vein ligation and bile duct ligation models, respectively. In the rats with acetic acid, colitis lesion area, colonic mucosal myeloperoxidase activity, and prostaglandin E2 generation were not different between the portal vein ligation groups with and without colitis. Nitric oxide activity was higher only in the groups with colitis, irrespective of the presence of portal hypertension. In the group of rats with iodoacetamide colitis, colonic lesion area and colonic mucosal myeloperoxidase activity were similar in all groups with colitis. Colonic mucosal prostaglandin E2 generation was lower in the portal vein ligation and bile duct ligation rats with colitis compared with a control group. We concluded that rats with experimental portal hypertension do not have increased damage when induced by either acetic acid or iodoacetamide.

Risk and case fatality rate of meningitis in patients with liver cirrhosis

Bacterial infections are major causes of morbidity and death in patients with liver cirrhosis. The risk of bacterial meningitis in these patients is unknown, however. In this study on a nation-wide cohort of 22,743 patients with liver cirrhosis in Denmark an incidence rate of bacterial meningitis of 54.4 per 100,000 was found [95% confidence interval (CI) 40.3-71.9]. The highest incidence rate was found in patients with alcoholic cirrhosis, 65.3 per 100,000 person-years (95% CI 46.2-89.6), compared with 34.6 per 100,000 person-years (95% CI 17.3-61.9) in patients with non-alcoholic cirrhosis. The 30-d case fatality rate was 53.1% (95% CI 38.3-67.5), and high age and alcoholic cirrhosis were associated with the highest case fatality rates. The main bacterial pathogens were pneumococci and unspecified bacteria. These findings suggest that patients with liver cirrhosis are at increased risk of bacterial meningitis with a poor prognosis.

Patients with stable uncomplicated cirrhosis have normal neutrophil function

BACKGROUND

Neutrophil function has been reported to be abnormal in patients with cirrhosis. In order to evaluate the relative contribution of hepatocellular dysfunction and portalsystemic shunting of blood to these abnormalities, neutrophil function was studied in 18 patients with cirrhosis and portal hypertension. Nine patients, with extrahepatic portal hypertension (EPH) caused by portal vein thrombosis, who had no clinical, biochemical or histologic evidence of liver disease were also studied.

METHODS

Superoxide generation, phagocytosis, degranulation, leukotriene B4 release, candidacidal activity and quantitative and qualitative expression of the cell surface adhesive marker CD11b/CD18 were measured in these patients as well as in age- and gender-matched controls.

RESULTS

Patients with cirrhosis were found to have a small but statistically significant decrease in the expression of the CD18 component of MAC1 in N-formyl-methionyl-leucyl-phenylalanine-stimulated neutrophils (P = 0.04). No significant differences were found between either of the two patient groups and the control group for any of the other parameters of neutrophil function tested.

CONCLUSIONS

These were unexpected findings in the light of data published elsewhere, which indicate impaired neutrophil function in patients with cirrhosis. The study suggests that patients with stable, uncomplicated cirrhosis and patients with EPH have normal neutrophil function.

Enhanced polymorphonuclear neutrophil-mediated endothelial cell injury and its relation to high surgical mortality rate in cirrhotic patients

OBJECTIVE

A high incidence of complications has been documented in patients with cirrhosis after operations. Recently, polymorphonuclear neutrophils (PMN) have been revealed to have the capacity to injure vascular endothelium and to cause organ damage. Furthermore, the altered function of PMN has been shown in patients with cirrhosis. However, there are few reports investigating the interaction between PMN and endothelial cells and its relation to a high incidence of postoperative complications in cirrhosis. The aim of this study was to evaluate PMN-mediated endothelial cell injury in patients with cirrhosis.

METHODS

Patients were divided into two groups: those who had normal liver with metastatic liver carcinoma and those who had cirrhosis with hepatocellular carcinoma. All patients in both groups underwent hepatic resection. PMN were isolated from patients before operation. Human umbilical vein endothelial cells and PMN were cocultured after addition of phorbol myristate acetate. The release of lactate dehydrogenase (LDH) and thrombomodulin in the cocultured medium and the elastase activity in PMN suspension were measured.

RESULTS

The release of both LDH and thrombomodulin in the group with cirrhosis was significantly higher than in the group with normal liver. The elastase activity was similarly higher in the group with cirrhosis than in the group with normal liver. The surgical morbidity rate was remarkably higher in the group with cirrhosis (50%) than in the group with normal liver (0%).

CONCLUSIONS

This study shows that PMN have an enhanced potential to cause endothelial cell injury in patients with cirrhosis. This PMN "priming" may be responsible for the occurrence of postoperative complications in patients with cirrhosis after hepatectomy.

Impaired mesenteric leukocyte recruitment in experimental portal hypertension in the rat

Increased incidence of septic complications in human and experimental portal hypertension has been documented. Because development of an inflammatory response is essential in defense against infectious agents, the aim of this study was to assess leukocyte-endothelial cell interactions in an experimental model of portal hypertension. Intravital microscopy studies showed that under baseline conditions, leukocyte rolling, adhesion, and emigration in mesenteric venules were similar in control, sham operated (SO), and partial portal vein ligated (PPVL) rats. Compared with either control or SO rats, PPVL animals exhibited a markedly reduced recruitment of rolling, adherent, and emigrated leukocytes in response to leukotriene B(4) (LTB(4)) stimulation. Similarly, platelet-activating factor (PAF) superfusion, which induced a large increment in leukocyte rolling and adherence in control and SO rats, was without any effect in PPVL animals. Endothelial P-selectin expression in control rats, as measured by the double radio-labeled monoclonal antibody (mAb) technique, was not modified by LTB(4), but significantly increased in response to PAF. PPVL rats had a significantly lower expression of P-selectin after stimulation with PAF. Neutrophils isolated from PPVL rats exhibited increased L-selectin shedding and CD11b up-regulation in response to PAF and LTB(4), compared with neutrophils isolated from SO rats. These observations indicate that portal hypertension is associated with a defective inflammatory response, which is manifested as a decreased recruitment of rolling leukocytes, and subsequently reduced adhesion/emigration. This defect appears to result from a reduced endothelial P-selectin up-regulation and increased L-selectin shedding.

Oxygen radical formation, proliferative activity and phagocytic capacity of cultivated macrophages from cirrhotic rat livers

A method to isolate and cultivate macrophages from Macronodular-cirrhotic rat livers was developed in order to characterize them biochemically, by comparing various functional parameters in macrophage cell cultures from controls and cirrhotic livers. Cells were prepared from female Wistar rats, made cirrhotic by treatment with thioacetamide, by means of a pronase-collagenase digestion method followed by a nycodenz gradient and elutriation. The yield of macrophages was 8.9 x 10(6) cells/g for controls and 10.6 x 10(6) cells/g for cirrhotic livers. The vitality of the cells was > 95%. Forty-eight hours after cultivation, the purity of the cell fractions amounted to 94% and 91% in controls and in the experimental group, respectively. Nitric oxide synthesis was more markedly stimulated by lipopolysaccharide (LPS) in cultures from cirrhotic livers than in those from controls (25 +/- 4 vs 5.8 +/- 1 nmol/10(6) cells/72 hours). Interferon-gamma (IFN-gamma) induced the nitric oxide synthase more rapidly in macrophage cultures from cirrhotic livers than in controls. The production of superoxide anions by macrophages from cirrhotic livers stimulated by zymosan was significantly lower by about 40% when compared with the controls. Incorporation of 3H-thymidine was increased to 250% in cultivated macrophages from thioacetamide-treated rats in comparison with macrophages from untreated animals. The stimulated phagocytic activity of cultivated macrophages from cirrhotic livers did not differ significantly from that of the controls. The data presented provide evidence that it is possible to isolate and to cultivate macrophages from macronodular-cirrhotic livers with high yield and vitality. They are characterized by enhanced proliferation, reduced formation of superoxide anions, and increased production of nitric oxide.

Inhibition of PAF synthesis by stimulated human polymorphonuclear leucocytes with cloricromene, an inhibitor of phospholipase A2 activation

1. A phospholipase A2 (PLA2) represents the key enzyme in the remodelling pathway of platelet-activating factor (PAF) synthesis in human polymorphonuclear (PMN) leucocytes. 2. PLA2 activation is also the rate-limiting step for the release of the arachidonic acid utilized for the synthesis of leukotrienes in stimulated leucocytes; however, it is unknown whether the PLA2s involved in the two biosynthetic pathways are identical. 3. Cloricromene (8-monochloro-3-beta-diethylaminoethyl-4-methyl-7-ethoxy- carbonylmethoxy coumarin) is an antithrombotic coumarin derivative which inhibits platelet and leucocyte function and suppresses arachidonic acid liberation by interfering with PLA2 activation. 4. The aim of the present study was to assess whether chloricromene inhibits PAF synthesis by stimulated human polymorphonuclear leucocytes (PMNs). 5. Cloricromene (50-500 microM) inhibited in a concentration-dependent manner the release of PAF, as measured by h.p.l.c. bioassay, from A23187-stimulated PMNs. Significant inhibition (45%) of PAF-release was obtained with 50 microM cloricromene and the IC50 was 85 microM. Mepacrine (500 microM), a non-specific PLA2 inhibitor, strikingly reduced PAF release. 6. The incorporation of [3H]-acetate into [3H]-PAF induced by serum-treated zymosan in human PMNs was also inhibited concentration-dependently by cloricromene, with an IC50 of 105 microM. Mepacrine also suppressed [3H]-acetate incorporation into [3H]-PAF. 7. Cloricromene did not affect the activities of the enzymes involved in PAF-synthesis acetyltransferase or phosphocholine transferase. 8. Our data demonstrate that cloricromene, an inhibitor of PLA2-activation in human leucocytes, reduces the synthesis of PAF by stimulated PMNs. This finding has a twofold implication: the PLA2s (or the mechanisms that regulate their activation) involved in PAF synthesis and arachidonate release in human leucocytes are either identical or else indistinguishable by their sensitivity to cloricromene; the inhibition of PAF release by activated leucocytes may contribute to the antithrombotic and anti-ischaemic activities exerted by cloricromene.