Deficient response of IL-6 impaired liver regeneration after hepatectomy in patients with viral hepatitis

BACKGROUND/AIMS

Liver regeneration after surgical resection is still a serious concern. The present study is designed to understand the relations between liver injury/regeneration and cytokines after hepatectomy with viral hepatitis.

METHODOLOGY

Twenty-one consecutive patients undergoing liver resection were studied, which included two patients with biliary tract cancer, three patients with hepatic metastases from colorectal cancer, and sixteen patients with primary liver tumor. They were also divided into two groups according to the existence of chronic viral hepatitis: 10 patients with viral hepatitis and 11 patients without viral hepatitis.

RESULTS

Viral hepatitis reduced pre-operative liver function (ICG-R15 and platelet count) with raised levels of sFas. Interestingly, this also reduced postoperative surge of IL-6, but not HGF, though they were equally at basal levels pre-operatively. Recovery of liver size, calculated with resected liver mass and volumetry with CT scan, was deteriorated in liver with viral hepatitis, but any difference of postoperative liver damage was observed between two groups.

CONCLUSIONS

Viral infection, somehow, increased sFas level pre-operatively, but does not influence the post-operative liver injury. Deficient response of IL-6, but not HGF, may be a major cause for poor liver regeneration after hepatectomy in patients with viral hepatitis independent from liver injury.

Significant correlation between surgical stress of hepatectomy and changes in the serum levels of HGF, IL-6 and soluble Fas in patients with viral hepatitis

BACKGROUND/AIMS

Liver damage after hepatectomy is still a serious concern. The present study was designed to clarify the relations between liver injury/surgical stress and cytokines after hepatectomy, in patients with viral hepatitis.

METHODOLOGY

Ten consecutive patients undergoing hepatectomy were studied, all with hepatocellular carcinoma due to viral hepatitis. Blood samples for interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), hepatocyte growth factor (HGF), soluble Fas (sFas), soluble Fas Ligand and soluble tumor necrosis factor receptor (sTNFR) assays were collected before the operation and at the end of the operation.

RESULTS

There was a significant and positive correlation between the change in the serum level of HGF and preoperative liver function (ICG-R15). Notably, there were significant correlations between surgical stress and IL-6, HGF and sFas, but not sIL-6R and sTNFR. Furthermore, there was significant correlation between postoperative liver function (total bilirubin, albumin) and HGF, IL-6.

CONCLUSIONS

There was a close relationship between surgical stress and HGF, IL-6 and sFas after hepatectomy in patients with viral hepatitis. It was useful for the evaluation of surgical stress of hepatectomy to estimate the serum level of HGF, IL-6 and sFas.

Preoperative oral administration of pentoxifylline ameliorates respiratory index after cardiopulmonary bypass through decreased production of IL-6

Activation of inflammatory response during cardiopulmonary bypass (CPB) may lead to considerable post-operative mortality. Recently, pentoxifylline (PTX), a methylxanthine derivative, has been reported to be effective in inhibiting proinflammatory cytokine production. This study aimed to determine whether or not PTX prevented CPB-induced systemic inflammatory response syndrome (SIRS) in patients undergoing cardiovascular surgery. Thirty adult patients were randomly separated into 2 experimental groups and 1 control group of 10 patients each. The experimental group received peroral PTX administration (Group 1: 600 mg/day, Group 2: 900 mg/day), while the control group did not. In Group 1 and Group 2, PTX administration was started on preoperative day 5 and continued for 5 days. Serum levels of PTX and IL-6 were measured just before and at 4 h after CPB using HPLC and ELISA, respectively. Respiratory index (RI) before and at 4 h after CPB was calculated, and serum levels of C-reactive protein (CRP) and fibrinogen on postoperative day 1 were also determined. There were no significant differences in age, body weight, sex, surgical procedures, CPB time, haemodynamics or risk factors among the 3 groups. Serum IL-6 level and RI index after CPB in Group 2 were significantly decreased compared with those in Group 1 and the control group. These results, therefore, suggested that preoperative daily administration of 900 mg/day PTX contributed to the attenuation of CPB-induced SIRS and had a beneficial effect on the postoperative course after cardiovascular surgery.

[Bacteria isolated from surgical infections and its susceptibilities to antimicrobial agents--special references to bacteria isolated between April 2006 and March 2007]

Tendency of isolated bacteria from infections in abdominal surgery during the period from April 2006 to March 2007 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 474 strains including 23 strains of Candida spp. were isolated from 170 (75.2%) of 226 patients with surgical infections. Two hundred and twenty-six strains were isolated from primary infections, and 224 strains were isolated from postoperative infections. From primary infections, anaerobic Gram-negative bacteria were predominant, followed by aerobic Gram-negative bacteria, while from postoperative infections aerobic Gram-positive bacteria were predominant, followed by anaerobic Gram-negative bacteria. Among aerobic Gram-positive bacteria, the isolation rate of Staphylococcus spp. was higher from postoperative infections, while Enterococcus spp. was higher from primary infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Klebsiella pneumoniae, Enterobacter cloacae and Pseudomonas aeruginosa, in this order, and from postoperative infections, P. aeruginosa was the most predominantly isolated, followed by E. coli and E. cloacae. Among anaerobic Gram-negative bacteria, the isolation rate of Bilophila wadsworthia was the highest from primary infections, followed by Bacteroides fragilis and from postoperative infections, B. fragilis was most predominately isolated, followed by Bacteroides caccae, Bacteroides thetaiotaomicron and B. wadsworthia in this order. In this series, we noticed no methicillin-resistant Staphylococcus aureus, nor multidrug-resistant P. aeruginosa. There were three strains of methicillin-resistant coagulase-negative Staphylococcus aureus, but all of them had good susceptibilities against various anti-MRSA antibiotics. We should carefully follow up B. wadsworthia.

Mechanism of impaired regeneration of fatty liver in mouse partial hepatectomy model

BACKGROUND AND AIM

The mechanism of injury in steatotic liver under pathological conditions been extensively examined. However, the mechanism of an impaired regeneration is still not well understood. The aim of this study was to analyze the mechanism of impaired regeneration of steatotic liver after partial hepatectomy (PH).

METHODS

db/db fatty mice and lean littermates were used for the experiments. Following 70% PH, the survival rate and recovery of liver mass were examined. Liver tissue was histologically examined and analyzed by western blotting and RT-PCR.

RESULTS

Of 35 db/db mice, 25 died within 48 h of PH, while all of the control mice survived. Liver regeneration of surviving db/db mice was largely impaired. In db/db mice, mitosis of hepatocytes after PH was disturbed, even though proliferating cell nuclear antigen (PCNA) expression (G1 to S phase marker) in hepatocytes was equally observed in both mice groups. Interestingly, phosphorylation of Cdc2 in db/db mice was suppressed by reduced expression of Wee1 and Myt1, which phosphorylate Cdc2 in S to G2 phase.

CONCLUSIONS

In steatotic liver, cell-cycle-related proliferative disorders occurred at mid-S phase after PCNA expression. Reduced expression of Wee1 and Myt1 kinases may therefore maintain Cdc2 in an unphosphorylated state and block cell cycle progression in mid-S phase. These kinases may be critical factors involved in the impaired liver regeneration in fatty liver.

Small liver graft regenerates through immediate increase of HGF and IL-6--possible involvement of sinusoidal tensile/shear stress in small liver graft

BACKGROUND/AIMS

The mechanisms whereby grafts in the recipients can be primed for regeneration following living donor liver transplantation (LDLT) are poorly understood. The present study was designed to understand the mechanism for posttransplant regeneration in small-for-size liver graft.

METHODOLOGY

Out of LDLT cases, we examined patients with end-stage liver cirrhosis and subsequent transplantation. A total of 16 patients were divided into 2 groups, group L (large graft) and group S (small graft). We examined the serum biochemical markers and cytokines preoperatively and postoperatively. We also carried out hemodynamic analysis by measuring the portal and arterial peak velocity.

RESULTS

The differences in ages, preoperative biochemical markers and MELD score between the two groups were not statistically significant. Though differences in the preoperative levels of IL-6, sIL-6R and HGF were not significant between the two groups, IL-6 and HGF levels in group S significantly increased postoperatively. Immediate and significant increase of Vp max was also observed in group S. Two weeks after LDLT, the regeneration rate in group S was significantly higher than that in group L.

CONCLUSIONS

These findings may allow us to speculate that immediate increase of portal pressure, reflecting sinusoidal tensile/shear stress, accelerates liver regeneration through immediate induction of IL-6 and HGF.

Preoperative proximal splenic artery embolization: a safe and efficacious portal decompression technique that improves the outcome of live donor liver transplantation

Terminal liver cirrhosis is associated with marked severe portal hypertension, which increases the risk of intraoperative hemorrhage and graft hyper-perfusion, especially, in small-for-size graft. In cases with developed collateral vessels, we often face difficulties in perihepatic dissection with blood stanching against bleeding during recipient hepatectomy. For aseptic preoperative portal decompression, we established the proximal splenic artery embolization (PSAE) technique. Sixty adult living donor liver transplantation recipients with viral/alcoholic hepatic failure were divided into two groups; PSAE group (n = 30) and non-PSAE (n = 30). In the PSAE group, the splenic artery was embolized proximal to the splenic hilum 12-18 h before surgery. PSAE enabled shortening of operating time, reduced blood loss, led to less need for transfusion, and significantly reduced the post-transplant portal venous velocity and ascites. PSAE was not associated with complications, e.g., splenic infarction, abscess, or portal thrombosis. Six of the non-PSAE patients required additional surgical intervention to resolve postoperative hemorrhage and three patients required secondary PSAE for arterial-steal-syndrome. The hospital mortality rate of PSAE patients (3.3%) was significantly better than that of the PSAE group (13.3%, P < 0.05). Preoperative noninvasive PSAE makes more efficient use of portal decompression; thus, it can potentially contribute to improvement of outcome.

Effect of adenosine receptor subtypes stimulation on mixed lymphocyte reaction

The cell-to-cell interaction through binding of intercellular adhesion molecule (ICAM)-1 on monocytes to their ligands lymphocyte function-associated antigen (LFA)-1 on T-cells plays important roles in cytokine production and T-cell proliferation. Interleukin (IL)-18, which plasma levels are elevated in patients during acute rejection following organ transplantation, induces the expression of ICAM-1 on monocytes, production of interferon (IFN)-gamma and IL-12 and lymphocyte proliferation during human mixed lymphocyte reaction. Activation of the adenosine A(2A) receptor on during reperfusion of various tissues has been found to markedly reduce ischemia-reperfusion injury. In the present study, we examined the effect of adenosine at increasing concentrations ranging from 0.1 to 100 microM on the IL-18-enhanced expression of ICAM-1, production of IFN-gamma and IL-12 and lymphocyte proliferation during human mixed lymphocyte reaction. Adenosine inhibited the IL-18-initiated immune responses. The IC(50) values of adenosine for inhibition of the IL-18-enhanced ICAM-1 expression, IFN-gamma production and lymphocyte proliferation were 20 microM, respectively. The actions of adenosine depended on the stimulation of adenosine A(2A) receptor. An inhibitor of protein kinase A (PKA) at 100 microM inhibited the actions of adenosine, suggesting that PKA might be involved in the actions of adenosine. On the other hand, the stimulation of adenosine A(1) and A(3) receptor blocked the actions of adenosine A(2A) receptor stimulation. These results suggest that adenosine inhibits the immune responses during mixed lymphocyte reaction via adenosine A(2A) receptor.

Action profiles of statins and calcineurin inhibitors during human mixed lymphocyte reaction

The cell-to-cell interaction through binding intercellular adhesion molecule (ICAM)-1 and CD40 on monocytes and their ligands such as lymphocyte function-associated antigen (LFA)-1 and CD40 ligand (CD40L) on T-cells plays roles in cytokine production and T-cell proliferation. Interleukin (IL)-18, which is elevated in the plasma during acute rejection after organ transplantation, induces the expression of ICAM-1 and CD40 on monocytes, the production of interferon (IFN)-gamma and IL-12 and the proliferation of T-cells during the human mixed lymphocyte reaction (MLR). In addition to the cholesterol lowering effect, statins improve patient survival and decrease rejection episodes in transplant recipients. In the present study, we investigated the difference of effect of statins and calcineurin inhibitors during MLR. 3-Hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, fluvastatin and pravastatin and statin-derived LFA-1 inhibitors, LFA703 and LFA878, which did not inhibit HMG-CoA reductase, suppressed the production of IFN-gamma and IL-12 and the lymphocyte proliferation as well as the expression of ICAM-1 and CD40 on monocytes regardless of the presence of IL-18. However, the calcineurin inhibitors, tacrolimus and cyclosporine A (CsA), inhibited the IL-18-enhanced cytokine production and lymphocyte proliferation without any effect on the adhesion molecule expression. Thus, the action mechanism of stain is different from that of calcineurin inhibitors.

[Bacteria isolated from surgical infections and its susceptibilities to antimicrobial agents--special references to bacteria isolated between april 2003 and march 2004]

Tendency of isolated bacteria from infections in abdominal surgery during the period from April 2005 to March 2006 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 384 strains including 18 strains of Candida spp. were isolated from 161 (70.3%) of 229 patients with surgical infections. One hundred and ninty-five strains were isolated from primary infections, and 171 strains were isolated from postoperative infections. From primary infections, aerobic Gram-negative bacteria and aerobic Gram-positive bacteria were predominant, while aerobic Gram-positive bacteria were predominant from postoperative infections. The isolation rate of aerobic Gram-positive bacteria, such as Enterococcus spp. and Staphylococcus aureus were higher from both types of infections. Among anaerobic Gram-positive bacteria, the isolation rate of Peptostreptococcus spp. was the highest from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Pseudomonas aeruginosa, Klebsiella spp. in this order, and from postoperative infections, E. coli was the most predominantly isolated, followed by Klebsiella pneumoniae and P. aeruginosa. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group was the highest from both primary and postoperative infections. In this series, we noticed no vancomycin-resistant Gram-positive cocci, nor multidrug-resistant P. aeruginosa. But cefazolin-resistant E. coli producing extended spectrum fl-lactamase was seen in 5.0 per cents. We should be carefully followed up the facts that the increasing isolation rates of B. fragilis group and Bilophila wadsworthia which were resistant to both penicillins and cephems.

The immunosuppressive effects of nicotine during human mixed lymphocyte reaction

Cell-to-cell interaction through binding intercellular adhesion molecule (ICAM)-1, B7.1, B7.2 and CD40 on monocytes and their ligands on T-cells plays roles in cytokine production and T-cell proliferation. Interleukin (IL)-18, which is elevated in the plasma during acute rejection after organ transplantation, induces the expression of ICAM-1, B7.1, B7.2 and CD40, production of interferon (IFN)-gamma and IL-12 and proliferation of lymphocytes during human mixed lymphocyte reaction. Nicotine is known to inhibit the production of pro-inflammatory cytokines from macrophages through the stimulation of nicotinic acetylcholine receptor alpha7 subunit. In the present study, we examined the effect of increasing concentrations ranging from 0.1 to 100 microM of nicotine on the expression of ICAM-1, B7.1, B7.2 and CD40, production of IFN-gamma and IL-12 and proliferation of lymphocytes during mixed lymphocyte reaction treated with IL-18 at 100 ng/ml for 48 h. Nicotine inhibited the expression of adhesion molecules, cytokine production and lymphocyte proliferation. The IC50 values of nicotine for inhibition of the IL-18-enhanced ICAM-1 expression, IFN-gamma production and proliferation were 1, 1 and 2 microM, respectively. A non-selective and a selective antagonist for nicotinic acetylcholine receptor alpha7 subunit, mecamylamine and alpha-bungarotoxin abolished the effects of nicotine. The actions of nicotine might depend on stimulation of nicotinic acetylcholine receptor alpha7 subunit. Nicotine induced prostaglandin E(2) production during mixed lymphocyte reaction. The inhibitors of cyclooxygenase (COX)-2 and protein kinase A (PKA) at 100 microM inhibited the actions of nicotine, suggesting that the endogenous prostaglandin E(2) might be, at least, partially involved the actions of nicotine.

Effects of adenosine on adhesion molecule expression and cytokine production in human PBMC depend on the receptor subtype activated

BACKGROUND AND PURPOSE

Adenosine suppresses immune responses through adenosine(2A) (A(2A)) receptors, by raising intracellular cAMP. Interleukin (IL)-18 up-regulates the expression of intercellular adhesion molecule (ICAM)-1 on monocytes, leading to production of pro-inflammatory cytokines such as IL-12, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha by human peripheral blood mononuclear cells (PBMC). We have previously demonstrated that elevation of cAMP inhibits this IL-18-induced expression of adhesion molecules. In the present study, we examined the effect of adenosine on the IL-18-induced up-regulation of ICAM-1 on human monocytes and production of IL-12, IFN-gamma and TNF-alpha by PBMC.

EXPERIMENTAL APPROACH

The expression of ICAM-1 was examined by flow cytometry. IL-12, IFN-gamma and TNF-alpha were determined by ELISA assay.

KEY RESULTS

Adenosine inhibited the IL-18-induced up-regulation of ICAM-1 on human monocytes and it abolished the IL-18-enhanced production of IL-12, IFN-gamma and TNF-alpha. While an A(2A) receptor antagonist reversed the action of adenosine, an A(1) or A(3) receptor antagonist enhanced them. An A(2A) receptor agonist, CGS21680, mimicked the effects of adenosine and its effects were abolished not only by the A(2A) receptor antagonist but also by A(1) or A(3) receptor agonists. Activation via A(2A) receptors resulted in elevation of cAMP in monocytes, whereas the stimulation of A(1) or A(3) receptors inhibited it, suggesting that intracellular signal transduction following ligation of A(2A) receptors might be blocked by activation of A(1) or A(3) receptors.

CONCLUSIONS AND IMPLICATIONS

Adenosine differentially regulates IL-18-induced adhesion molecule expression and cytokine production through several subtypes of its receptors.

Stimulation of alpha7 nicotinic acetylcholine receptor inhibits CD14 and the toll-like receptor 4 expression in human monocytes

The lipopolysaccharide (LPS)-receptor complex, CD14/toll-like receptor 4, is known to play a role in the immune responses during sepsis. Excessive inflammation and tumor necrosis factor (TNF)-alpha synthesis have been reported to cause morbidity and mortality in endotoxemia and sepsis. Cell-to-cell interaction through the engagement between intercellular adhesion molecule 1, B7.1, and CD40 on monocytes and their ligands on T cells has been suggested to play a role in the inflammatory response such as TNF-alpha and interleukin 10 production. Nicotine, with the stimulation of the nicotinic acetylcholine receptor alpha7 subunit (alpha7-nAChR), has now become the focus of attention because of its anti-inflammatory effects. However, little is known about the mechanism of the inhibitory effects induced by nicotine on the LPS-induced immune responses. In the present study, we found that nicotine suppressed the expression of CD14, toll-like receptor 4, intercellular adhesion molecule 1, B7.1, and CD40 on monocytes and the production of TNF-alpha, but not interleukin 10, in human peripheral blood mononuclear cells in the presence of LPS. The actions of nicotine were reversed by a nonselective and a selective alpha7-nAChR antagonist, mecamylamine and alpha-bungarotoxin, respectively. Therefore, nicotine might inhibit the LPS receptor complex expression via alpha7-nAChR, thus leading to a decrease in the adhesion molecule expression and TNF-alpha production. Moreover, we demonstrated that a nuclear factor-kappaB and a p38 mitogen-activated protein kinase inhibitor mimicked the actions of nicotine in the presence of LPS. These results suggested that the nuclear factor-kappaB and p38 mitogen-activated protein kinase might be involved in the actions of nicotine.

Protective effects of nafamostat mesilate on liver injury induced by lipopolysaccharide in rats: possible involvement of CD14 and TLR-4 downregulation on Kupffer cells

Nafamostat mesilate (NM) is a synthetic protease inhibitor with various biological effects. To determine its effect on liver injury related to sepsis, we investigated the effects of NM on lipopolysaccharide (LPS)-induced liver injury. Wistar rats were allocated into two groups; the NM group underwent intraperitoneal NM administration 30 min before LPS administration, and the control group underwent PBS administration. Serum AST and ALT levels were significantly decreased in NM-treated rats. Reduced levels of TNF-alpha, IL-1beta, and IFN-gamma were observed after LPS administration in NM-treated rats. No significant differences were observed in IL-6 levels between the NM and the control group. In contrast, HGF levels were significantly increased only in control rats. NM treatment decreased protein and mRNA levels of TLR-4 and CD14. Our data suggest that NM treatment has protective effects against LPS-induced hepatotoxicity through downregulation of TLR4 and CD14 in liver, which decreased TNF-alpha, IL-1beta, and IFN-gammaproduction in liver.

Effect of nicotine on IL-18-initiated immune response in human monocytes

Nicotine is thought to inhibit the production of proinflammatory cytokines from macrophages through an anti-inflammatory pathway that is dependent on nicotinic acetylcholine receptor alpha7 subunit (alpha7-nAChR). IL-18, an important proinflammatory cytokine, is reported to induce the expression of adhesion molecules on monocytes, thus enhancing cell-to-cell interactions with T-cells and contributing to IL-18-initiated cytokine production. Accordingly, inhibition of IL-18 suppresses systemic inflammatory responses. In the present study, we found that nicotine inhibited the IL-18-enhanced expression of ICAM-1, B7.2, and CD40 on monocytes, and the production of IL-12, IFN-gamma, and TNF-alpha by PBMC. A nonselective and a selective alpha7-nAChR antagonist, mecamylamine, and alpha-bungarotoxin abolished the effects of nicotine, suggesting that this depends on alpha7-nAChR stimulation. It is reported that nicotine induces prostaglandinE2 (PGE(2)) production in PBMC through the up-regulation of cyclooxygenase (COX)-2 expression. PGE(2) is known to activate the EP2/EP4-receptor, leading to an increase in cyclic adenosine monophosphate (cAMP) levels and protein kinase A (PKA) activity. Consistent with this, we found that COX-2 and PKA inhibitors prevented the effects of nicotine on adhesion molecule expression and cytokine production, indicating that the mechanism of action of nicotine may be via endogenous PGE(2) production.

alpha7 Nicotinic acetylcholine receptor stimulation inhibits lipopolysaccharide-induced interleukin-18 and -12 production in monocytes

Nicotine inhibited interleukin (IL)-18 and -12 production in lipopolysaccharide (LPS)-stimulated monocytes, and the action of nicotine was antagonized by a non-selective and a selective alpha7 nicotinic acetylcholine receptor (alpha7-nAChR) antagonist, suggesting that the stimulation of alpha7-nAChR may be involved in the action of nicotine. Nicotine is reported to induce prostaglandin E(2) (PGE(2)) production in monocytes through the up-regulation of cyclooxygenase (COX)-2 expression. PGE(2) is known to increase cAMP levels and to activate protein kinase A (PKA). COX-2 and PKA inhibitors prevented the action of nicotine, indicating that the mechanism of action of nicotine may be via endogenous PGE(2) production.

Hypothesis: the antitumor activities of statins may be mediated by IL-18

Statins, which inhibit 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase, are thought to reduce the risk of cancer through the inhibition of Ras farnesylation and serum lipid level. A pleiotropic proinflammatory cytokine, interleukin-18 (IL-18), is reported to exhibit significant antitumor activities through the activation of cytotoxic T lymphocytes and natural killer cells and the inhibition of angiogenesis. Previously, we found that pravastatin, fluvastatin, and simvastatin induced the production of IL-18 in human monocytes. The addition of mevalonate abolished the IL-18 production induced by pravastatin, fluvastatin, and simvastatin, indicating that the IL-18 production might be a result of the inhibition of HMG-CoA reductase. We present a new hypothesis that the production of IL-18 might play roles in the action of statins on cancer.

Cimetidine Induces Interleukin-18 Production through H2-Agonist Activity in Monocytes

The present study demonstrates a possible mechanism for the improvement of gastrointestinal cancer patients' prognosis by the histamine receptor type 2 (H2R) antagonist cimetidine. This agent, but not the H2R antagonists ranitidine and famotidine, induced the production of an antitumor cytokine, interleukin (IL)-18, by human monocytes and dendritic cells (DC). In fact, ranitidine and famotidine antagonized cimetidine-induced IL-18 production. Cimetidine induced the activation of caspase-1, which is reported to modify immature IL-18 to mature/active IL-18, and the elevation of intracellular cAMP, leading to the activation of protein kinase A (PKA). The PKA inhibitor H89 abolished the IL-18 production induced by cimetidine. Moreover, the effects of cimetidine on IL-18 production were reproduced in peripheral blood mononuclear cells from wild-type mice, but not in those from H2R knockout mice. In conclusion, cimetidine, a partial agonist for H2R, has a pharmacological profile different from ranitidine and famotidine, possibly contributing to its antitumor activity on gastrointestinal cancers.

Ex vivo adenoviral gene transfer of constitutively activated STAT3 reduces post-transplant liver injury and promotes regeneration in a 20% rat partial liver transplant model

Signal transducer and activator of transcription-3 (STAT3) is one of the most important transcription factors for liver regeneration. This study was designed to examine the effects of constitutively activated STAT3 (STAT3-C) on post-transplant liver injury and regeneration in a rat 20% partial liver transplant (PLTx) model by ex vivo adenoviral gene transfer. Adenovirus encoding the STAT3-C gene was introduced intraportally into liver grafts and clamped for 30 min during cold preservation. After orthotopic PLTx, liver graft/body weights and serum biochemistry were monitored, and both a histological study and DNA binding assay were performed. STAT3-C protein expression and its binding to DNA in the liver graft were confirmed by Western blotting and electrophoretic mobility shift assay (EMSA), respectively. This treatment modality promoted post-Tx liver regeneration effectively and rapidly. The serum levels of alanine aminotransferase/aspartate aminotransferase (AST/ALT) and bilirubin decreased in rats with STAT3-C. However, albumin (a marker of liver function) did not. Ex vivo gene transfer of STAT3-C to liver grafts reduced post-Tx injury and promoted liver regeneration. Thus, the activation of STAT3 in the liver graft may be a potentially effective clinical strategy for improving the outcome of small-for-size liver transplantation.

The immunosuppressive effects of ciprofloxacin during human mixed lymphocyte reaction

Interleukin (IL)-18, which is elevated in the plasma during acute rejection after organ transplantation, is known to induce the expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40 and CD40 ligand (CD40L) on monocytes, the production of interferon (IFN)-gamma and IL-12 and the proliferation of lymphocytes during the human mixed lymphocyte reaction (MLR). Ciprofloxacin (CIP), which is useful for the clinical treatment of infections due to its antibacterial properties after transplantation, was shown to suppress the IFN-gamma and IL-12 production, the lymphocyte proliferation and the ICAM-1, B7.1, B7.2 and CD40 expression on monocytes during MLR in the presence of IL-18. CIP also induced the production of prostaglandin (PG) E2. In order to determine whether the effects of CIP on the expression of the activation markers were due to CIP-dependent production of PGE2, we examined the effect of cyclooxygenase (COX)-2 and protein kinase A (PKA) inhibitors on the actions of CIP. Thereby, the inhibitors were found to abolish the actions of CIP. These results therefore suggest that CIP might exert its immune modulatory effects via the production of PGE2.

[Bacteria isolated from surgical infections and its susceptibilities to antimicrobial agents--special references to bacteria isolated between April 2003 and March 2004]

Tendency of isolated bacteria from infections in general surgery during the period from April 2004 to March 2005 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 645 strains including 17 strains of Candida spp. were isolated from 226 (79.0%) of 286 patients with surgical infections. Three hundred and seventeen strains were isolated from primary infections, and 345 strains were isolated from postoperative infections. From primary infections, anaerobic Gram-positive bacteria and anaerobic Gram-negative bacteria were predominant, while aerobic Gram-positive bacteria were predominant from postoperative infections. The isolation rate of aerobic Gram-positive bacteria, such as Enterococcus spp. and Staphylococcus aureus were higher from both types of infections. Among anaerobic Gram-positive bacteria, the isolation rate of Peptostreptococcus spp. was the highest from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Pseudomonas aeruginosa, Klebsiella pneumoniae and Citrobacter freundii in this order, and from postoperative infections, P. aeruginosa was the most predominantly isolated, followed by E. coli, E. cloacae, and K. pneumoniae. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group was the highest from both primary infections followed by Bilophila wadsworthia. While the isolation rate of B. fragilis group was also the highest from postoperative infections, the following bacteria were Bacteroides thetaiotaomicron and B. wadsworthia in this order. In this series, we noticed no vancomycin-resistant Gram-positive cocci, but a few strains of moderately arbekacin-resistant MRSA. Carbapenem-resistant P. aeruginosa but not multidrug-resistant was seen in 13.3 per cents. Also cefazolin-resistant E. coli probably producing extended spectrum beta-lactamase was seen in 7.0 per cents. We should be carefully followed up the facts that an increasing isolation rates of B. fragilis group and B. wadsworthia which were resistant to both penicillins and cephems.

THE EFFECT OF CIPROFLOXACIN ON CD14 AND TOLL-LIKE RECEPTOR-4 EXPRESSION ON HUMAN MONOCYTES

CD14/toll-like receptor (TLR)-4 complex on monocytes/macrophages can bind lipopolysaccharide (LPS) and transduce the signals intracellularly. An antibacterial drug, ciprofloxacin (CIP), has been reported to modulate the inflammatory and immune responses. In the present study, we examined the effects of CIP on the LPS-induced activation of monocytes isolated from human peripheral blood mononuclear cells (PBMC). CIP suppressed the expression of CD14, TLR-4, intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, and CD40 and the production of tumor necrosis factor (TNF)-alpha induced by LPS in monocytes. CIP induced the production of prostaglandin (PG)E2 and increased intracellular cyclic adenosine monophosphate (cAMP) levels. Cyclooxygenase (COX)-2 inhibitors, NS398 and indomethacin, reversed the effects of CIP on TNF-alpha production and reduced the levels of different surface antigens, whereas a protein kinase A (PKA) inhibitor, H89, did not. Therefore, CIP might regulate the TNF-alpha production induced by LPS by inhibiting the expression of LPS receptor complex, which seems to be mediated by COX-2 but not the cAMP/PKA pathway.

The role of a protease inhibitor against hepatectomy

BACKGROUND/AIMS

Nafamostat Mesilate (NM) is a synthetic serine protease inhibitor that is capable of inhibiting the various coagulation factors. To determine whether NM may also be useful in attenuating operative invasiveness, we investigated the effects of perioperative administration of NM on postoperative serum levels of proinflammatory cytokine IL-6 and hepatocyte growth factor (HGF).

METHODOLOGY

Thirty patients undergoing hepatectomy with hepatocellular carcinoma, biliary carcinoma and metastatic colorectal cancer were enrolled in this study. These patients were separated into two groups; high invasive group (resected liver volume: 1000cm3 <) and less invasive group (resected liver volume: 1000cm3 >). The high invasive group of 11 patients received perioperative administration of NM (Group NM), while the less invasive group of 19 patients did not (Group C). Serum levels of IL-6, HGF and soluble IL-6 receptor (sIL-6R) were simultaneously measured on preoperative and postoperative day ('day 0', 'day 7').

RESULTS

Serum IL-6 levels on day 0 were significantly elevated and returned to preoperative levels on day 7 in both groups, and the serum IL-6 level in Group NM on day 0 was significantly lower than that in Group C on day 0. Serum HGF levels on day 0 and day 7 were significantly higher in Group NM than those in Group C. Compared with healthy control subjects, the higher serum level of HGF on the preoperative day in all patients was attributable to tumor-burden. The sIL-6R levels on day 0 decreased in both groups, and their levels in Group NM were significantly lower than those in Group C, suggesting that increased synthesis of IL-6/sIL-6R complex which could accelerate liver regeneration.

CONCLUSIONS

These results suggested that perioperative administration of NM may attenuate surgical stress by decreasing production of proinflammatory cytokine IL-6, and may accelerate liver regeneration through stimulation with the IL-6/sIL-6R complex and possible involvement of increased production of HGF.