Septic Liver Damage Research Articles

L-AP Alleviates Liver Injury in Septic Mice by Inhibiting Macrophage Activation via Suppressing NF-κB and NLRP3 Inflammasome/Caspase-1 Signal Pathways.

Liver injury and progressive liver failure are severe life-threatening complications in sepsis, further worsening the disease and leading to death. Macrophages and their mediated inflammatory cytokine storm are critical regulators in the occurrence and progression of liver injury in sepsis, for which effective treatments are still lacking. l-Ascorbic acid 6-palmitate (L-AP), a food additive, can inhibit neuroinflammation by modulating the phenotype of the microglia, but its pharmacological action in septic liver damage has not been fully explored. We aimed to investigate L-AP's antisepticemia action and the possible pharmacological mechanisms in attenuating septic liver damage by modulating macrophage function. We observed that L-AP treatment significantly increased survival in cecal ligation and puncture-induced WT mice and attenuated hepatic inflammatory injury, including the histopathology of the liver tissues, hepatocyte apoptosis, and the liver enzyme levels in plasma, which were comparable to NLRP3-deficiency in septic mice. L-AP supplementation significantly attenuated the excessive inflammatory response in hepatic tissues of septic mice in vivo and in cultured macrophages challenged by both LPS and ATP in vitro, by reducing the levels of NLRP3, pro-IL-1β, and pro-IL-18 mRNA expression, as well as the levels of proteins for p-I-κB-α, p-NF-κB-p65, NLRP3, cleaved-caspase-1, IL-1β, and IL-18. Additionally, it impaired the inflammasome ASC spot activation and reduced the inflammatory factor contents, including IL-1β and IL-18 in plasma/cultured superannuants. It also prevented the infiltration/migration of macrophages and their M1-like inflammatory polarization while improving their M2-like polarization. Overall, our findings revealed that L-AP protected against sepsis by reducing macrophage activation and inflammatory cytokine production by suppressing their activation in NF-κB and NLRP3 inflammasome signal pathways in septic liver.

Chitinase 3 like 1 deficiency ameliorates lipopolysaccharide-induced acute liver injury by inhibition of M2 macrophage polarization

Chitinase 3-like-1 protein (CHI3L1) is involved in various infectious diseases, especially sepsis. Aberrant CHI3L1 expression potentially plays a critical role in chronic inflammation because a considerable number of macrophages are associated with immune/inflammatory diseases. In this study, we examined the effect of CHI3L1 on hepatic sepsis injury using a lipopolysaccharide (LPS)-induced model. LPS-treated CHI3L1 knockout (KO) mice exhibited a higher survival rate than LPS-treated CHI3L1 wild-type (WT) mice. In addition, hepatic injury-related enzyme levels (aspartate transaminase, alanine transaminase, and lactate dehydrogenase) decreased in CHI3L1 KO mice sera, suggesting attenuated LPS-induced septic liver damage in CHI3L1 KO mice. A greater reduction in the mRNA and protein expressions of M2 polarization markers, such as MRC1, ARG1, IL-10, and IL-4, was observed in LPS-induced CHI3L1 KO mice livers than in LPS-induced WT mice livers. Nonetheless, no change in the mRNA and protein expressions of M1 polarization markers, such as INOS, CD86, TNF-α, and IL6, was noted in LPS-induced CHI3L1 KO mice livers compared with those in LPS-induced WT and KO mice. Similar to the in vivo scenario, liver CHI3L1 depletion in LPS-treated HEP3B cells significantly decreased M2 polarization marker protein expression. However, M1 polarization marker protein expression did not differ significantly. These results suggest that CHI3L1 depletion decreases M2 macrophage polarization, and this effect is potentially associated with the alleviation of liver sepsis in CHI3L1 KO mice.

Inhibition of Chitinase-3-like-1 expression by K284 ameliorates lipopolysaccharide-induced acute liver injury through down regulation of CXCL3

Chitinase 3 like 1 protein (CHI3L1) is involved in various types of infectious disease, especially sepsis. Aberrant expression of CHI3L1 could play a critical role in inflammation and immune responses. Previously, we found that compound K284 has the highest binding activity to CHI3L1. In this study, we investigated the effect of K284 on liver injury during sepsis using a lipopolysaccharide (LPS)-induced C57BL/6 mouse model. We found that the survival rate was a 65 % in LPS + K284 injected mice whereas it was 0% in LPS-treated mice. The serum levels of hepatic injury-related enzymes were decreased in K284-injected mice, indicating that septic liver damage was alleviated by K284. In addition, expression levels of M2 polarization markers were reduced in liver tissues of K284-injected mice. Depletion of CHI3L1 in LPS-treated THLE-2 cells decreased the expression of M2 polarization marker proteins. We investigated the major pathway involved in the observed effects and found that CXCL3 expression is correlated with that of CHI3L1. We found that the expression of CXCL3 was lowered in liver tissues of LPS + K284-treated mice compared with LPS-treated mice. M2 polarization-related cytokine levels were increased by the combination of LPS and recombinant CXCL3, but decreased by K284. M2 polarization-related cytokines, CHI3L1 and CXCL3 expression levels were decreased by CXCL3 siRNA, and further decreased by combination treatment of CXCL3 siRNA and K284. Therefore, CXCL3 might be a significant chemokine involved in the reduction of LPS-induced liver injury during sepsis by K284. Our findings indicate that K284 could be a suitable treatment for sepsis like hepatic injury.

MiR-425-5p improves inflammation and septic liver damage through negatively regulating the RIP1-mediated necroptosis

Sepsis, a systemic inflammatory response syndrome, is still a common cause of death even the patients who are in the intensive care unit. Alleviating septic liver damage may be effective in improving sepsis. Necroptosis and miRNAs have been regarded as a potential target in sepsis. The aim of this work is to explain the potential role of miR-425-5p in septic liver damage. LPS was intraperitoneal-injection to C57BL/6 mice for sepsis, and hepatocytes treated with septic serum in vitro. H&E staining for histological evaluation, luciferase reporter assay for target validation, and qRT-PCR, WB, and ELISA analysis for assessment of miR-425-5p, RIP1, inflammatory factors, and LDH levels. Down-regulated miR-425-5p and up-regulated RIP1/RIP3 were in LPS-induced sepsis mice. Liver damage, RIP1-mediated necroptosis, IL-1β, and TNF-α were suppressed by miR-425-5p agomiR, but further aggravated by miR-425-5p antagomiR. Furthermore, we demonstrated miR-425-5p targeted the 3'UTR of RIP1 mRNA to inhibit RIP1 expression and activated RIP1 reversed miR-425-5p-induced suppression of necroptosis and inflammation in septic hepatocytes. The data suggest miR-425-5p negatively controls the RIP1-mediated necroptotic signaling cascades and inflammation, and sepsis-related liver damage. miR-425-5p/RIP1 axis is a potential therapeutic strategy for sepsis-related liver damage through necroptosis and inflammation.

Genipin Ameliorates Carbon Tetrachloride-Induced Liver Injury in Mice via the Concomitant Inhibition of Inflammation and Induction of Autophagy.

Genipin, as the most effective ingredient of various traditional medications, encompasses antioxidative, anti-inflammatory, and antibacterial capacities. More recently, it is suggested that genipin protects against septic liver damage by restoring autophagy. The purpose of the current study was to explore the protective effect of genipin against carbon tetrachloride- (CCl4-) induced acute liver injury (ALI) and its underlying molecular machinery. Our results indicated that treatment with genipin significantly reduced CCl4-induced hepatotoxicity by ameliorating histological liver changes, decreasing the aspartate aminotransferase and alanine transaminase levels, alleviating the secretion of inflammatory cytokines, and promoting autophagic flux. Moreover, genipin effectively induced the conversion of LC3 and inhibition of p62 accumulation. The liver expressions of ATG5, ATG7, and ATG12 were significantly increased by genipin pretreatment in the ALI mice model. This protective effect may be mediated by the inhibition of mTOR and the activation of p38 MAPK signaling pathways. Meanwhile, genipin attenuated CCl4-induced inflammatory response by inhibiting the NF-κB and STAT3 signaling pathway. In addition, pretreatment with autophagy inhibitor 3-methyladenine (3-MA) or inhibition of p38 MAPK by SB203580 abolished the hepatoprotective effect of genipin. Taken together, our study implicates that genipin has a protective potential against CCl4-induced hepatotoxicity, which might be strongly associated with the induction of autophagy and the attenuation of inflammatory response.

Nonlinear Multimodal Imaging Characteristics of Early Septic Liver Injury in a Mouse Model of Peritonitis.

Sepsis constitutes a life-threatening organ failure caused by a deregulated host response to infection. Identifying early biomolecular indicators of organ dysfunction may improve clinical decision-making and outcome of patients. Herein we utilized label-free nonlinear multimodal imaging, combining coherent anti-Stokes Raman scattering (CARS), two-photon excited autofluorescence (TPEF), and second-harmonic generation (SHG) to investigate the consequences of early septic liver injury in a murine model of polymicrobial abdominal infection. Liver tissue sections from mice with and without abdominal sepsis were analyzed using multimodal nonlinear microscopy, immunofluorescence, immunohistochemistry, and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Twenty-four hours after the induction of sepsis, hepatic mRNA of inflammatory cytokines and acute phase proteins was upregulated, and liver-infiltrating myeloid cells could be visualized alongside hepatocellular cytoplasmic translocation of high mobility group box 1. According to the statistical analysis based on texture feature extraction followed by the combination of dimension reduction and linear discriminant analysis, CARS (AUC = 0.93) and TPEF (AUC = 0.83) showed an excellent discrimination between liver sections from septic mice and sham-treated mice in contrast to SHG (AUC = 0.49). Spatial analysis revealed no major differences in the distribution of sepsis-associated changes between periportal and pericentral zones. These data suggest early alterations in hepatic lipid distribution and metabolism during liver injury and confirm nonlinear multimodal imaging as a promising complementary method for the real-time, label-free study of septic liver damage.

Surgical correction of the chronic liver purulent-septic lesions

Purpose of the study. The purpose of the study is to improve the results of surgical treatment of patients with purulent-septic lesion of the liver substantiating the indication for resection method use.
 Material and methods. The work is based on a comparative analysis of the results of examination and treatment of 64 patients aged 10 to 81 years old, with chronic liver abscesses in the department of surgery and liver transplantation during the 1995–2016 periods.
 According to the tasks of the study patients are divided into two groups. In 30 (46,8%) patients (the study group), various types of anatomical resection of the liver with a purulent lesion were performed without its dissection during the operation; in 34 (53,2%) patients (group of comparison) they performed the disclosure, sanation, drainage of purulent cavity. The majority of patients with chronic liver abscesses treated the abscess with a puncture or drainage method under the control of ultrasound in other medical institutions of Ukraine.
 Results. The results of diagnosis and treatment of 64 patients for chronic liver abscesses from 1995 to 2016 are analyzed. In the study group, the patients performed anatomical resection of the liver, in the comparison group – standard surgical interventions – the disclosure and drainage of the abscess of the liver. The duration of antibiotic therapy after surgery in the comparison group is significantly higher than in the study group, respectively, 22 ± 3,4 and 5,75 ± 1,6 days; p < 0,001. Second-line antibacterial drugs after draining operations were used more often (p < 0,001) than after resection interventions, respectively, in 94,1 and 6,6% of cases. The duration of treatment of patients in the hospital after surgery in the study group was less than in the comparison group, according to 15,1 ± 0,7 and 27,3 ± 3,05 days; total 25,9 ± 1,4 and 45,7 ± 3,45 days (p < 0,001). After drainage operations, drainages from the abdominal cavity were removed later than after resection interventions, respectively, 17,1 ± 2,8 and 6,35 ± 1,1 days (p < 0,001), through.
 Conclusion. Resection for chronic purulentseptic lesions of the liver is the priority methods of surgical treatment. The analysis of the obtained results allows us to conclude that resection technologies contribute to the rapid normalization of physical and social rehabilitation of patients with septic liver damage.

Surgical correction of chronic purulent-septic lesions of the liver

Introduction: The aim of the study is to improve the results of surgical treatment of patients with purulent-septic lesion of the liver by substantiating the indications and using the resection method. Method: According to the objectives of the study patients are divided into two groups. In 30 (46.8%) patients (the study group), various types of anatomical resection of the liver with a purulent lesion were performed without its dissection during the operation; in 34 (53.2%) patients (group of comparison) they performed the disclosure, sanation, drainage of purulent cavity. Result: The results treatment of 64 patients with chronic liver abscesses during the period from 1995 to 2016 were analyzed. In the group under study, anatomical resection of the liver was performed in patients, in the comparison group, standard surgery was the opening and drainage of the abscess of the liver. The duration of antibiotic therapy after the operation in the comparison group is significantly (p <0.001) higher than that in the study (22 ± 3.4) and (5.75 ± 1.6) days, respectively. Antibacterial preparations of the second line after drainage operations were used reliably (p <0,001) more often than after resection interventions - respectively in 94,1 and 6,6% of observations. The duration of treatment of patients in the hospital after the operation in the study group was significantly lower than in the comparison group - respectively (15,1 ± 0,7) and (27,3 ± 3,05) days; total - (25,9 ± 1,4) and (45,7 ± 3,45) days (p <0,001). Conclusion: Resection interventions in chronic purulent-septic liver lesions are the priority methods of surgical treatment. The analysis of the obtained results allows us to conclude that resection technologies contribute to the rapid normalization of physical and social rehabilitation of patients with septic liver damage.

Citrullinated Histone H3: Early Biomarker of Neutrophil Extracellular Traps in Septic Liver Damage

BackgroundNeutrophil extracellular traps (NETs) play a crucial role in host defense, but excess and prolonged interaction of NETs with platelets can cause severe inflammation and host organ damage. Modification of histone H3 by citrullination is involved in in vitro NET formation. The phosphodiesterase III inhibitor, cilostazol (Ciz), which has a protective effect on liver sinusoidal endothelial cells and inhibits platelet aggregation, may prevent organ damage caused by excess NETosis. In this study, we investigated whether citrullinated histone H3 (H3Cit) could serve as a biomarker for the detection of critical liver damage in sepsis and the efficacy of phosphodiesterase-III inhibition for preventing the liver dysfunction induced by NETosis. Materials and methodsMice injected with lipopolysaccharide (LPS; 1 mg/kg) were used as a sepsis model with or without treatment with Ciz (200 mg/kg). H3Cit, myeloperoxidase, and neutrophil elastase levels were measured by immunohistochemistry. We evaluated H3Cit-positive neutrophils in the peripheral blood by flow cytometry. ResultsImmunohistochemistry revealed that H3Cit-, neutrophil elastase-, and myeloperoxidase-positive cell numbers in the livers peaked at 12 h after LPS administration. However, flow cytometry showed a significant increase in H3Cit-positive neutrophils in the peripheral blood only 4 h after LPS injection. Treatment with Ciz significantly ameliorated all parameters. ConclusionsH3Cit is a useful biomarker for early detection of NETosis or liver dysfunction, and Ciz may be an effective treatment for septic liver damage.

Antagonistic interaction between cordyceps sinensis and exercise on protection in fulminant hepatic failure.

Herb supplements are widely used by Asian athletes; however, there are no studies evaluated the co-effects of exercise and herb supplements on hepatic failure. In this study, D-GalN/LPS-induced fulminant hepatic failure was used to examine whether there are synergistic or antagonistic effects of exercise and Cordyceps sinensis (CS). Mice were randomly divided into eight groups: control, swimming exercise for four weeks, D-GalN/LPS challenge, swimming exercise plus D-GalN/LPS, 20 mg/kg or 40 mg/kg CS pretreated for four weeks plus D-GalN/LPS, and swimming exercise combined with 20 mg/kg or 40 mg/kg CS pretreatment plus D-GalN/LPS. Either exercise or 40 mg/kg CS pretreatment alone significantly decreased D-GalN/LPS-induced TNF-α, AST, NO, apoptotic-related proteins, and hepatocyte apoptosis. Exercise or 40 mg/kg CS alone increased the IL-10 and D-GalN/LPS-suppressed Superoxide Dismutase (SOD) level. However, no protective or worse effect was observed in the mice treated with exercise preconditioning combined 40 mg/kg CS compared to those receive exercise alone or CS alone. TNF-α, AST, NO level, caspase-3 activity, and hepatocytes apoptosis were not significantly different in the exercise combined with 40 mg/kg CS compared to mice challenged with D-GalN/LPS. The IL-10 level was significantly decreased after D-GalN/LPS stimulation in the mice received exercise combined with 40 mg/kg CS, indicating the combination strongly reduced the anti-inflammatory effect. In summary, preconditioning exercise or CS pretreatment alone can protect mice from septic liver damage, but in contrast, the combination of exercise and CS does not produce any benefit. The antagonistic interactions between exercise and CS imply taking CS is not recommended for people who undertake regular exercise.

Inducer of heme oxygenase‐1 cobalt protoporphyrin accelerates autophagy and suppresses oxidative damages during lipopolysaccharide treatment in rat liver

Mitochondrial damage and subsequent oxidative stresses play important roles in the pathogenesis of sepsis-induced organ failure. Recently, autophagy, the major degradation pathway involved in mitochondrial quality control, was reported as a cellular adaptive response to oxidative stresses. The aim of the present study was to elucidate the molecular mechanism that underlies hepatic damage during lipopolysaccharide (LPS) treatment. We also try to determine if the damage can be attenuated by administration of cobalt protoporphyrin (CoPP), a potent heme oxygenase-1 (HO-1) inducer. Five-week-old male Sprague-Dawley rats were injected i.p. with 15 mg/kg LPS. To determine if hepatic damage following LPS administration can be attenuated by HO-1, CoPP was injected s.c. for 4 days consecutively at 24-h intervals. After treatment with LPS, the liver was obtained and analyzed. A large reduction in liver mitochondrial protein and induction of autophagy were observed in LPS-treated rats. Electron microscopic and immunohistochemical analyses demonstrated autophagic vacuoles in LPS-treated rat liver. Oxidative stress markers (4-hydroxy-2-nonenal and 8-hydroxy-2'-deoxyguanosine) were increased in LPS-treated animals; CoPP treatment ablated these alterations. An inhibitor for the opening of mitochondrial permeability transition pore, cyclosporine A, suppressed oxidative stress as well as liver damage during LPS administration. CoPP promoted autophagy and prevented rats from liver damage during LPS administration. HO-1 promotes autophagy and elimination of damaged mitochondria thereby repressing oxidative stress in LPS-treated rat liver, revealing a novel mechanism for protection by HO-1 against septic liver damage.

Elimination and active extrusion of liver mitochondrial proteins during lipopolysaccharide administration in rat

The purpose of the present study was to identify molecular markers of hepatic damage during lipopolysaccharide (LPS) treatment. LPS (15 mg/kg of bodyweight) or vehicle was injected i.p. into 5-week-old male Sprague-Dawley rats. Proteins were extracted from the liver and were electrophoresed to examine the changes in the protein compositions during LPS treatment. Using a proteomic approach, major LPS-responsible protein in the liver was determined. A massive reduction in the levels of carbamoyl phosphate synthase-1 (CPS1), one of the most abundant proteins in liver mitochondria, was revealed during LPS administration. Electron microscopic and immunofluorescence analyses revealed large vacuoles, which were often localized in the vicinity of mitochondria, in the LPS-treated rat liver. Furthermore, we found that CPS1 is released into the circulation prior to liver damage marker alanine aminotransferase, indicating the active extrusion of CPS1 during LPS administration. Another liver mitochondrial protein, ornithine transcarbamylase, is also released into the circulation, implicating active extrusion of mitochondrial proteins. These phenomena are accelerated by a heme oxygenase inducer cobalt protoporphyrin whilst suppressed by a lysosome inhibitor chloroquine. Plasma CPS1 should be a possible marker of septic liver damage and may be involved in systemic responses elicited by septic shock.

Simvastatin Attenuates Hepatic Sensitization to Lipopolysaccharide After Partial Hepatectomy

Hepatic resection may be curative in patients with hepatobiliary malignancies but excessive loss of liver volume may cause hepatic dysfunction and increase susceptibility to subsequent postoperative infections and sepsis. Herein, we hypothesized that pretreatment with simvastatin may protect against lipopolysaccharide (LPS)-induced liver damage after partial hepatectomy. Male C57Bl/6 mice underwent 68% hepatectomy and exposed to LPS after 24h. Animals were pretreated with simvastatin (0.02 and 0.2mg/kg). Serum alanine aminotransferase (ALT) and tumor necrosis factor-alpha (TNF-alpha) as well as leukocyte infiltration and hepatocyte apoptosis were examined 6h after LPS challenge. An in vitro endothelial cell adhesion assay was used to study the mechanisms of simvastatin on leukocyte adhesion and the role of P-selectin and lymphocyte function antigen-1 (LFA-1). Partial hepatectomy increased the sensitivity of the remnant liver tissue to LPS-provoked tissue injury. Simvastatin pretreatment reduced the LPS-induced increase in serum levels of ALT by 65% in hepatectomized animals. Moreover, simvastatin decreased leukocyte infiltration and hepatocyte apoptosis in the liver remnant of endotoxemic mice. LPS-provoked serum levels of TNF-alpha were decreased by 83% in hepatectomized animals treated with simvastatin. TNF-alpha-induced leukocyte adhesion as well as P-selectin expression in endothelial cells and LFA-1 function were inhibited by simvastatin in vitro. These novels findings demonstrate that simvastatin protects the remnant liver against endotoxemic injury following major hepatectomy. Thus, simvastatin reduced LPS-induced leukocyte recruitment and hepatocyte apoptosis in the liver remnant. One key mechanism appears to be related to the inhibition of TNF-alpha formation and function (P-selectin expression) as well as to direct actions on LFA-1 function. Thus, simvastatin may represent a novel therapeutic approach to prevent septic liver damage after partial liver resection.

COX-2 Inhibition Improves Immune System Homeostasis and Decreases Liver Damage in Septic Rats

To evaluate cyclooxygenase-2 (COX-2) inhibition by NS-398 in septic rats with respect to immunologic derangements and hepatic damage. Six sham rats (Sham), 24 rats that underwent experimentally induced sepsis using cecal ligation and puncture (CLP), and 24 rats that underwent induced sepsis after treatment with NS-398 (NS-398), were compared. Sham rats were immediately sacrificed. Six each of CLP and NS-398 animals were sacrificed at 3, 6, 12, and 24 h after induction of sepsis. From each rat was obtained liver for COX-2 mRNA copy number determination and blood for quantification of alanine transaminase (ALT), aspartate aminotransferase (AST), interleukin 10 (IL-10), interleukin 6 (IL-6), and tumor necrosis factor alpha (TNFalpha) levels, and CD4:CD8 ratios. Sham rats had a lower COX-2 mRNA copy number than NS-398 rats, which had a lower copy number than CLP rats. CLP and NS-938 rats had IL-10 and IL-6 levels above Sham levels. NS-938 rat IL-10 levels were greater and IL-6 levels less than those of CLP rats. For CLP rats, TNF production sharply declined and then increased above Sham levels; NS-398 rat TNF production was consistently mildly elevated above Sham levels. CD4:CD8 ratios sharply dropped over time; NS-398 showed a more modest decline. CLP rats showed unrelenting climbs in AST and ALT values; NS-398 rat levels peaked at 6 h and returned to normal after 12 h; the biochemical evidence of protection against septic liver damage was also seen morphologically, with ultrastructural and histologic normalization of nuclear appearances 12 h after sepsis induction with NS-398 pretreatment. Septic rats given the COX-2 inhibitor NS-398 showed amelioration of cytokine and cellular immunologic imbalances and decreased liver injury.

P38 mitogen-activated protein kinase-dependent chemokine production, leukocyte recruitment, and hepatocellular apoptosis in endotoxemic liver injury.

To determine the role of p38 mitogen-activated protein kinase (MAPK) signaling in endotoxin-induced liver injury. MAPKs have been reported to play a potential role in regulating inflammatory responses, but the role of p38 MAPK signaling in chemokine production, leukocyte recruitment, and hepatocellular apoptosis in the liver of endotoxemic mice is not known. Endotoxin-induced leukocyte-endothelium interactions were studied by use of intravital fluorescence microscopy in the mouse liver. Tumor necrosis factor-alpha (TNF-alpha) and CXC chemokines, liver enzymes, and apoptosis were determined 6 hours after endotoxin challenge. The specific p38 MAPK inhibitor SB 239063 was given immediately prior to endotoxin exposure. Phosphorylation and activity of p38 MAPK were determined by immunoprecipitation and Western blot. Endotoxin increased phosphorylation and activity of p38 MAPK in the liver, which was markedly inhibited by SB 239063. Inhibition of p38 MAPK signaling dose-dependently decreased endotoxin-induced leukocyte rolling, adhesion, and sinusoidal sequestration of leukocytes. SB 239063 markedly reduced endotoxin-induced formation of TNF-alpha and CXC chemokines in the liver. Indeed, the endotoxin-provoked increase of liver enzymes and hepatocellular apoptosis were abolished and sinusoidal perfusion was restored in endotoxemic mice treated with SB 239063. This study demonstrates that p38 MAPK signaling plays an important role in regulating TNF-alpha and CXC chemokine production in endotoxemic liver injury and that inhibition of p38 MAPK activity abolishes endotoxin-induced leukocyte infiltration as well as hepatocellular apoptosis. These novel findings suggest that interference with the p38 MAPK pathway may constitute a therapeutic strategy against septic liver damage.

Critical role of CXC chemokines in endotoxemic liver injury in mice.

Tissue accumulation of leukocytes constitutes a rate-limiting step in endotoxin-induced tissue injury. Chemokines have the capacity to regulate leukocyte trafficking. However, the role of CXC chemokines, i.e., macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (KC), in leukocyte recruitment, microvascular perfusion failure, cellular injury, and apoptosis in the liver remains elusive. Herein, mice were challenged with lipopolysaccharide (LPS) in combination with D-galactosamine, and intravital microscopy of the liver microcirculation was conducted 6 h later. It was found that immunoneutralization of MIP-2 and KC did not reduce LPS-induced leukocyte rolling and adhesion in postsinusoidal venules. In contrast, pretreatment with monoclonal antibodies against MIP-2 and KC abolished (83% reduction) extravascular recruitment of leukocytes in the livers of endotoxemic mice. Notably, endotoxin challenge increased the expression of CXC chemokines, which was mainly confined to hepatocytes. Moreover, endotoxin-induced increases of liver enzymes and hepatocellular apoptosis were decreased by more than 82% and 68%, respectively, and sinusoidal perfusion was restored in mice passively immunized against MIP-2 and KC. In conclusion, this study indicates that intravascular accumulation of leukocytes in the liver is independent of CXC chemokines in endotoxemic mice. Instead, our novel data suggest that CXC chemokines are instrumental in regulating endotoxin-induced transmigration and extravascular tissue accumulation of leukocytes. Indeed, these findings demonstrate that interference with MIP-2 and KC functions protects against septic liver damage and may constitute a potential therapeutic strategy to control pathological inflammation in endotoxemia.

DIFFERENTIATION OF LIVER GRAFT DYSFUNCTION BY TRANSPLANT ASPIRATION CYTOLOGY

Episodes of graft dysfunction are frequently observed after liver transplantation and can be due to different causes requiring specific therapy. In this study the usefulness and reliability of liver transplant aspiration cytology (TAC) for differential diagnosis of liver graft dysfunction is assessed. Out of more than 1500 TACs performed, 292 TACs, taken during episodes of liver dysfunction due to retrospectively defined causes, were analyzed. Immune activation and parenchymal damage in the aspirates were determined cytologically. In 63 episodes of acute rejection, marked immune activation was present in aspirate but not in blood, with varying degrees of hepatocyte damage and cholestasis. No or only minimal immune activation was observed in 86 cases of toxic, ischemic, or septic liver damage, but considerable parenchymal damage and cholestasis were observed. In 3 cases of hepatitis slight-to-moderate immune activation with large granular lymphocytes was found in the aspirate, while 17 cases of viral infection presented with slight-to-moderate immune activation in aspirate and blood. After successful treatment the cytologic patterns normalized, except when the cause of liver dysfunction persisted. Moreover, typical patterns of parenchymal changes were found for preservation damage of the liver (n = 108), fatty degeneration (n = 3), obstructive cholestasis (n = 5), and acute arterial ischemia (n = 2). One case of moderate subcapsular hematoma was the only complication observed (less than 0.1%). Thus, liver TAC is an easy, safe, and clinically useful method for differential diagnosis of liver graft dysfunction. In particular, differentiation between acute rejection and nonimmunologic causes of dysfunction is very reliable, but hepatitis and viral infections also present distinctive patterns in liver TAC.