Obstructive jaundice increases sensitivity to lipopolysaccharide via TLR4 upregulation: possible involvement in gut-derived hepatocyte growth factor-protection of hepatocytes

BACKGROUND

Patients with obstructive jaundice are prone to sepsis after biliary tract surgery. The present study was designed to determine the effect of biliary obstruction on cytokine responses to lipopolysaccharide (LPS).

METHODS

Wister rats were allocated into two groups; the BDL group underwent bile duct ligation, followed 2 weeks later by administration of LPS into the duodenum. The control group underwent sham operation, and similarly received enteral LPS. Specimens were collected serially, and applied for the assays.

RESULTS

Serum aspartate aminotransferase and alanine aminotransferase levels were significantly increased in BDL rats. High tumor necrosis factor alpha (TNF-alpha) and interleukin (IL)-6 levels in peripheral blood were observed 2 h after LPS administration in BDL rats. In contrast, no increases in both cytokines were noted in peripheral and portal blood in control rats. Baseline HGF levels in portal and peripheral blood in BDL rats were significantly higher than in control rats. LPS significantly increased hepatocyte growth factor (HGF) levels in portal blood and decreased in peripheral blood in BDL rats, but not in control rats. Immunohistochemical analysis revealed that BDL increased expressions of Toll-like receptor (TLR)4, CD14 and CD68 both in the small intestine and liver. Both TLR4 and CD14 mRNAs were upregulated in the small intestine and liver after LPS administration in BDL rats.

CONCLUSION

Obstructive jaundice and LPS stimulation induced TLR4 upregulation both in the liver and small intestine, which led to increased TNF-alpha and IL-6 production in liver and HGF production in the small intestine. The upregulation of TLR4 may lead to pathological and host defense reactions in obstructive jaundice complicated with Gram-negative bacterial infection.

β2-Adrenergic receptor stimulation inhibits LPS-induced IL-18 and IL-12 production in monocytes

We examined the effects of beta2-adrenergic receptor (beta2-AR) agonists on monocyte-derived cytokines, interleukin (IL)-18 and IL-12 production in lipopolysaccharide (LPS)-stimulated monocytes derived from human peripheral blood mononuclear cells (PBMCs), as in vitro model of sepsis. The study found that beta2-AR agonists inhibited IL-18 and IL-12 production in monocytes, and that AR agonist activity was antagonized by the selective beta2-AR antagonist, butoxamine. The selective beta2-AR agonists salbutamol and terbutaline induced a similar inhibitory pattern of IL-18 and IL-12 production. IL-12 production induced by LPS was inhibited by anti-IL-18 Ab, but IL-18 production by LPS was not inhibited by anti-IL-12 Ab, showing that LPS induced IL-18 production without IL-12 production. Therefore, the stimulation of beta2-AR might be beneficial in the treatment of sepsis through inhibiting LPS-elicited IL-18.

Expression of Phosphorylated Ser70of Bcl-2 Correlates with Malignancy in Human Colorectal Neoplasms

PURPOSE

Bcl-2 is a model apoptosis suppressor postulated to promote tumorigenesis. Recently, it has been reported that Bcl-2 undergoes phosphoregulation of its Ser70 to substantially alter its molecular function. Previous studies further suggest that such phospho-Bcl-2 regulation may influence tumor progression in colorectal and other cancers; however, phosphorylation status of the Ser70 of Bcl-2 (pSer70) in vivo in tumors remains obscure. To elucidate this question that may suggest the biological role, we molecularly screened a panel of human colorectal adenomas and adenocarcinomas for endogenous expression of pSer70 Bcl-2.

EXPERIMENTAL DESIGN

An antibody specific against pSer70 Bcl-2 was generated for thorough immunohistochemical examination of paraffin-embedded tumor specimens, allowing detection of the endogenously expressed antigen among a range of Bcl-2-positive colorectal neoplasms, including 75 tubular adenomas, 114 adenocarcinomas, and 15 cases of cancer in adenomas.

RESULTS

Loss of pSer70 Bcl-2 expression was observed in adenocarcinomas in a differentiation-dependent manner (positivities: well differentiated 63%, moderately differentiated 52%, and poorly differentiated 12%), whereas tubular adenomas maintained their expression (positivity 88%). Interestingly, an inverse correlation was found between expression of pSer70 Bcl-2 and Ki-67 antigen in those cases of cancer in adenoma (P < 0.01). It was further observed that loss of pSer70 Bcl-2 expression was associated with significantly shorter survival (P < 0.05) and correlated with clinical stages and lymph node metastasis (P < 0.05 and P < 0.05, respectively).

CONCLUSIONS

Loss of pSer70 Bcl-2 expression is closely linked to biological aggressiveness in colorectal tumors and represents a statistically significant molecular index for prognosis of patients with these tumors.

Simvastatin induces interleukin-18 production in human peripheral blood mononuclear cells

The effects of statins on immune response depend on the inhibition of 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase and leukocyte function-associated antigen (LFA)-1, which is a ligand of intercellular adhesion molecule (ICAM)-1. Simvastatin, an HMG-CoA reductase inhibitor with mild inhibition of LFA-1, induced the production of interleukin (IL)-18, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma in human peripheral blood mononuclear cells (PBMC). The IL-18 production is located upstream of the cytokine cascade activated by simvastatin. Moreover, simvastatin concentration-dependently inhibited the expression of ICAM-1 and induced the expression of CD40 on monocytes. In the presence of IL-18, simvastatin suppressed the expression of ICAM-1 and CD40 as well as the production of IL-12, TNF-alpha and IFN-gamma in PBMC, contributing to the anti-inflammatory effect of simvastatin. The effects of simvastatin were abolished by the addition of the product of the HMG-CoA reductase, mevalonate, indicating the involvement of HMG-CoA reductase in the action of simvastatin.

Effect of ciprofloxacin-induced prostaglandin E2 on interleukin-18-treated monocytes

Ciprofloxacin, a fluorinated 4-quinolone, is useful for the clinical treatment of infections due to its antibacterial properties and also modulates the immune response of monocytes isolated from human peripheral blood mononuclear cells. In the present study, we found that ciprofloxacin induced the production of prostaglandin E(2) in monocytes in a concentration-dependent manner regardless of the presence of interleukin-18 by enhancing the expression of cyclooxygenase-2 protein and that this in turn led to the elevation of intercellular cyclic AMP in monocytes via the stimulation of prostaglandin receptors. The prostaglandin E(2) and cyclic AMP production increased by ciprofloxacin was inhibited by indomethacin, a nonselective cyclooxygenase-2 inhibitor, and NS398, a selective cyclooxygenase-2 inhibitor. In addition, ciprofloxacin suppressed the interleukin-18-induced production of tumor necrosis factor alpha, gamma interferon, and interleukin-12 in peripheral blood mononuclear cells by inhibiting the expression of intercellular adhesion molecule 1, B7.1, B7.2, and CD40 on monocytes, and this effect could be reversed by the addition of indomethacin or NS398. These results indicate that ciprofloxacin exerts immunomodulatory activity via the production of prostaglandin E(2) and imply therapeutic potential of ciprofloxacin for the treatment of systemic inflammatory responses initiated by interleukin-18.

Prostaglandins E1 and E2 inhibit lipopolysaccharide-induced interleukin-18 production in monocytes

The purpose of this present study was to explore the therapeutic potential of prostaglandins E1 and E2 on the systemic inflammatory response evoked by endotoxin. Since interleukin-18, a monocyte-derived cytokine, is increased during sepsis, decreasing the production of interleukin-18 is important in treating this condition. Prostaglandin E1 and E2 inhibited interleukin-18 production in human monocytes treated with lipopolysaccharide and prostanoid IP-, EP2- and EP4-receptor agonists mimicked the effects of prostaglandins E1 and E2. Therefore, prostanoid IP, EP2- and EP4-receptors might be involved in the decrease in interleukin-18 production during sepsis.

Mast cell tryptase stimulates DLD-1 carcinoma through prostaglandin- and MAP kinase-dependent manners

We found that striptease-positive mast cells were abundant in the invasive front of human colon adenocarcinoma by examining 30 cases. Because tryptase has been suggested to be the agonist proteinase for protease-activated receptor-2 (PAR-2), we investigated the effects of stimulation of PAR-2 by tryptase on the cell signaling and proliferation of DLD-1, a human colon carcinoma cell line. PAR-2 stimulation by tryptase induced the increase in [Ca(2+)](i), which was desensitized by the prior application of PAR-2 activating peptide (AP). The proliferative responses of DLD-1 to tryptase and PAR-2 AP were associated with the phosphorylation of MEK and MAP kinase. Inhibition of MEK by PD98059 completely inhibited the proliferation-enhancing effects of tryptase and PAR-2 AP as well as phosphorylation of MAP kinase. Moreover, tryptase and PAR-2 AP stimulated the production of prostaglandin E2 and the inhibition of prostaglandin synthesis by indomethacin or NS398 resulted in the complete inhibition of the proliferative responses to tryptase and PAR-2 AP. Furthermore, the tryptase-stimulated proliferation of DLD-1 was concentration-dependently inhibited by nafamostat mesilate, a specific inhibitor of tryptase. These results as a whole indicated that tryptase has proliferative effects on DLD-1 through cyclooxygenase- and MAP kinase-dependent manners acting on PAR-2 by its proteolytic activity.

Involvement of prostaglandin receptors (EPR2–4) in in vivo immunosuppression of PGE2 in rat skin transplant model

BACKGROUND

Prostaglandin E2 (PGE2) is known to modulate immune responses and is widely viewed as a general immunosuppressant. There have been recognized four receptors for PGE2 (EP1-EP4 receptor) so far, and EP2 and EP4 receptors are mainly involved in the immunosuppressive effect of PGE2 in vitro. In the present study we examined the in vivo immunosuppressive effects of selective EP receptor agonists using a high-responder rat skin transplantation model.

MATERIALS AND METHODS

Skin allografts from ACI donors were transplanted onto LEW recipients. Agents were injected everyday between day 0 and day 5 after skin transplantation at the dose of 300 microg/kg subcutaneously. Survival of the skin allograft, histological changes and changes of the intragraft cytokine expressions were analyzed using the reverse transcription polymerase chain reaction (RT-PCR). We also assessed the mixed lymphocyte reaction (MLR) assay using splenocytes.

RESULTS

PGE2 significantly prolonged allograft survival (18.8+/-1.5 days) compared with untreated control (14.8+/-0.8 days). EP2R+EP3R+EP4R agonists also prolonged allograft survival (18.0+/-1.0 days) although EP3R agonist or EP2R+EP4R agonists alone failed (15.5+/-0.7, 15.4+/-1.3 days, respectively). RT-PCR analysis in the skin grafts demonstrated IL-10 up-regulation and IFN-gamma down-regulation in all groups except untreated control and EP2R agonist-treated groups. MLR was significantly reduced in groups of EP2R+EP4R agonists, EP2R+EP3R+EP4R agonists and PGE2, compared with untreated control.

CONCLUSIONS

The effect of PGE2 to prolong the survival of skin transplant requires the action of a combination of three receptors, i.e., EP2+EP3+EP4.

Prostaglandin E1-initiated immune regulation during human mixed lymphocyte reaction

Prostaglandin E1 (PGE1) has therapeutic value for transplantations due to its microvascular activity. Interleukin (IL)-18, which is elevated in plasma during the acute rejection after organ transplantation, elicits the expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40, and CD40 ligand (CD40L) on monocytes as well as the production of interferon (IFN)-gamma and IL-12 and proliferation of T-cells during the human mixed lymphocyte reaction (MLR) in an in vitro model of acute rejection. In contrast, PGE1 inhibits all the adhesion molecule expression, cytokine production and T-cell proliferation in the presence of IL-18. The effects of PGE1 depend on stimulation of the IP/EP2/EP4-receptor, and thus, PGE1 might have therapeutic potential for treating acute rejection due to its immune regulatory effect.

Differential effect of prostaglandins E1 and E2 on lipopolysaccharide-induced adhesion molecule expression on human monocytes

The effect of prostaglandins E1 and E2 on the 1 ng/ml lipopolysaccharide-induced expression of intercellular adhesion molecule (ICAM)-1, B7.1, B7.2, CD40 and CD40 ligand (CD40L) on monocytes was examined. Prostaglandin E1 suppressed B7.1 and CD40 expression, but prostaglandin E2 did not effect on any type of adhesion molecule expression. Both prostaglandins inhibited tumor necrosis factor (TNF)-alpha production and T-cell proliferation of lipopolysaccharide-treated human peripheral blood mononuclear cells (PBMC). Among prostaglandin E1 receptors (IP/EP1/EP2/EP3/EP4) agonists, ONO-1301, a prostanoid IP-receptor agonist, prevented B7.1 and CD40 expression. ONO-AE1-259-01 a prostanoid EP2-receptor agonist, ONO-AE1-329, a prostanoid EP4-receptor agonist, and ONO-1301 inhibited TNF-alpha production and T-cell proliferation. Moreover, anti-B7.1 and anti-CD40 Abs prevented lipopolysaccharide-induced TNF-alpha production and T-cell proliferation. Therefore, the effect of prostaglandin E1 on TNF-alpha production and T-cell proliferation might depend on the inhibition of B7.1 and CD40 expression, but that of prostaglandin E2 might be independent of adhesion molecules expression. In conclusion, the mechanism responsible for the effect of prostaglandin E1 on lipopolysaccharide-induced responses is distinct from that of prostaglandin E2.

[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 2003 to March 2004 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 455 strains including 14 strains of Candida spp. were isolated from 191(75.2%) of 254 patients with surgical infections. Two hundred and thirty-nine strains were isolated from primary infections, and 216 strains were isolated from postoperative infections. From primary infections, anaerobic Gram-positive bacteria and aerobic 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 Klebsiella pneumoniae, Enterobacter cloacae and Pseudomonas aeruginosa in this order, and from postoperative infections, E. coli was the most predominantly isolated, followed by P. aeruginosa, E. cloacae, and K. pneumoniae. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group was the highest from both types of infections. The isolation rate of anaerobic Gram-positive bacteria from primary infections and that of aerobic Gram-positive bacteria from postoperative infections were high in the last several years. In this series, we noticed no vancomycin-resistant Gram-positive cocci, but a few strains of moderately arbekacin-resistant MRSA. Carbapenm-resistant P. aeruginosa was seen in less than 10 per cents. Last year we noticed that there were cefazolin-resistant E. coli producing extended spectrum beta-lactamase, but there was no highly cefazolin-resistant E. coli in this year. In the next series, increase of both anaerobic bacteria and Enterococcus spp. should be carefully followed up.

Prolonged survival of donor-specific rat intestinal allograft by administration of bone-marrow-derived immature dendritic cells

It has been reported that intraportal administration of donor antigens induced donor-specific hyporesponsiveness. We studied here the effects of transplantation of BM-derived immature dendritic cells (imDCs) and mature DCs (mDCs) via portal vein on rat small intestinal allograft survival. This study comprised four treatment groups: 1) untreated controls; 2) FK506 alone; 3) intraportal donor-specific BM-derived imDCs transplantation+FK506; 4) mDCs/Tx+FK506. Allograft survival was minimal in control group (5.2+/-0.8 days) and maximal in imDC+FK506 group (28.4+/-3.0 days). The rats in mDC+FK506 group showed systemic inflammatory reaction due to GVHR, and died within 10 days after transplantation. The in vitro MLR reaction using imDCs was also strongly inhibited both in direct and indirect recognition pathways. The impact of imDCs for the specific induction of transplant tolerance may suggest that immunization with donor-specific imDCs has therapeutic potential in organ transplantation.

Nafamostat Mesilate Induces Production of Interleukin-12 and -18 in Human Peripheral Blood Mononuclear Cells

Little has been reported on the drugs inducing production of monocyte-derived cytokines like interleukin (IL)-18 and IL-12. We found that nafamostat mesilate elicits IL-12, IL-18, tumor necrosis factor-alpha and interferon-gamma production, and the expression of intercellular adhesion molecules-1, B7.1, B7.2, CD40, and CD40 ligand in human peripheral blood mononuclear cells. The cytokine production and adhesion molecule expression were abolished by anti-IL-12 and IL-18 antibodies. Therefore, IL-18 and IL-12 may play roles in the significant and immediate effects of nafamostat mesilate.

Effect of Antibodies Against Intercellular Adhesion Molecule-1, B7, and CD40 on Interleukin-18-Treated Human Mixed Lymphocyte Reaction

The interleukin (IL)-18 level in plasma is elevated during the acute rejection after organ transplantation. IL-18 elicits adhesion molecule expression as well as interferon-gamma/IL-12 production and T-cell proliferation in the human mixed lymphocyte reaction, an in vitro model of acute rejection. We examined whether antibodies (Abs) against intercellular adhesion molecule (ICAM)-1, B7, CD40, and CD40, ligand (CD40L) affect the cytokine production and T-cell proliferation. Anti-ICAM-1 and B7 Abs suppressed the cytokine production, while all Abs inhibited T-cell proliferation. ICAM-1 and B7 as well as CD40 may play different roles in the acute rejection.

??1-Adrenergic Receptor Antagonists Induce Production of IL-18 and Expression of ICAM-1 and CD40 in Human Monocytes

The activation of T cells plays a role in antitumor response. Monocytes activate T cells by inducing the cell-to-cell interaction that involves the engagement of adhesion molecules with their ligands, and the production of IL-18. The authors examined the effect of the quinazoline-based alpha1-adrenergic receptor antagonists bunazosin, doxazosin, prazosin, and terazosin on the expression of adhesion molecules such as ICAM-1, B7.1, B7.2, CD40, and CD40L on monocytes isolated from human peripheral blood mononuclear cells. Doxazosin, prazosin, and terazosin induced the expression of ICAM-1 and CD40 but had no effect on the expression of B7.1, B7.2, and CD40L. Moreover, IL-18 was detected in the medium of incubated monocytes treated with doxazosin, prazosin, and terazosin. Bunazosin did not affect adhesion molecule expression and IL-18 production, suggesting that the chemical structure of quinazoline might not be related to the effect of doxazosin, prazosin, and terazosin. Although caspase-1 inhibitor completely abolished the production of IL-18, anti-IL-18 mAb and caspase-1 inhibitor partially inhibited the increase in ICAM-1 and CD40 expression induced by doxazosin, prazosin, and terazosin. Doxazosin, prazosin, and terazosin can induce monocyte activation with a specific pattern of expression of adhesion molecules and IL-18 production, and this may lead to T-cell activation through the cell-to-cell interaction. The activation of T cells induced by the increase of the expression of ICAM-1 and CD40 and the production of IL-18 may be involved in the anti-cancer effects of doxazosin, prazosin, and terazosin.

Differential effect of LFA703, pravastatin, and fluvastatin on production of IL-18 and expression of ICAM-1 and CD40 in human monocytes

A novel, proinflammatory cytokine, interleukin (IL)-18 production was detected in the medium of human monocytes treated with 3-hydroxy-3-methylglutaryl coenzyme-A (HMG-CoA) reductase inhibitors, pravastatin, and fluvastatin (0.1 and 1 muM) but not with the statin-derived lymphocyte function-associated antigen-1 (LFA-1) inhibitor LFA703, which did not inhibit HMG-CoA reductase. Pravastatin and fluvastatin also induced the production of IL-18, tumor necrosis factor alpha (TNF-alpha) and interferon-gamma (IFN-gamma) in human peripheral blood mononuclear cells (PBMC) in contrast to LFA703. IL-18 production by PBMC is located upstream of the cytokine cascade activated by these statins. The IL-18-induced cytokine production was demonstrated to be dependent on adhesion molecule expression on monocytes. In the absence and presence of lower concentrations (0.1 and 1 ng/ml) of IL-18, pravastatin and fluvastatin inhibited the expression of intercellular adhesion molecule (ICAM)-1 and induced the expression of CD40, whereas LFA703 had no effect. In the presence of higher concentrations (5, 10, and 100 ng/ml) of IL-18, pravastatin, fluvastatin, and LFA703 similarly inhibited the expression of ICAM-1 and CD40 as well as the production of IL-12, TNF-alpha, and IFN-gamma in PBMC. The effects of pravastatin and fluvastatin but not LFA703 were abolished by the addition of mevalonate, indicating the involvement of HMG-CoA reductase in the action of pravastatin and fluvastatin. Thus, the effects of LFA703 were distinct from those of pravastatin and fluvastatin in the presence of lower concentrations of IL-18. It was concluded that LFA703 has the inhibitory effect on an IL-18-initiated immune response without any activation on monocytes.

The impact of portal infusion with donor-derived bone marrow cells and intracellular cytokine expression of graft-infiltrating lymphocytes on the graft survival in rat small bowel transplant model

BACKGROUND

Intraportal administration of alloantigen is reported to reduce antigen-specific immune responses, although the underlying mechanisms for the reduced immunological reactions, especially those of the graft, are poorly understood. We examined intracellular cytokine production by graft-infiltrating lymphocytes (GILs) and peripheral blood lymphocytes (PBLs) to elucidate the underlying mechanisms of beneficial effects on intraportal infusion of donor cells in rat small bowel transplantation (SBT).

METHODS

Recipient rats (Lewis) were transplanted with small bowel from ACI rats. Tacrolimus (Tac) was injected daily from days 0 to 4. Bone marrow cells of ACI rats were infused via the portal or tail vein on the day of surgery. On day 5, both GILs and PBLs collected from SBT graft and peripheral blood, respectively, were analyzed for intracellular cytokine production of recipient-derived alphabeta-T cells. The Th1/Th2 balance in each group was designated as the ratio of the percentage of GILs or PBLs staining positive for intracellular IL-4 or IFN-gamma, respectively. The total cell numbers of GILs from SBT graft were also counted.

RESULTS

Survival of recipients was markedly prolonged by the combination of Tac and donor-specific bone marrow infusion via the portal vein (DSBMI-PV-Tac) compared with the untreated control, Tac alone, or DSBMI tail vein plus Tac. DSBMI-PV-Tac significantly decreased the total cell numbers of GILs and also induced remarkable Th2-type response in GILs.

CONCLUSIONS

Our results indicate that DSBMI-PV-Tac decreased GILs and enhanced Th2-type response in SBT graft, both of which are associated with a significant prolongation of graft survival in SBT.

β2-Adrenergic Receptor Stimulation-Induced Immunosuppressive Effects Possibly through Down-Regulation of Co-Stimulatory Molecules, ICAM-1, CD40 and CD14 on Monocytes

We examined the effects of β2-adrenergic receptor (β2-AR) agonists on the expression of co-stimulatory molecules on lipopoly-saccharide (LPS)-stimulated human peripheral blood mononuclear cells. The study found that β2-AR agonists inhibited the expression of intercellular adhesion molecule-1 (ICAM-1), CD40 and CD14 on monocytes, and that AR agonist activity was antagonized by the selective β2-AR antagonist, butoxamine. The selective β2-AR agonists salbutamol and terbutaline induced a similar co-stimulatory molecule expression pattern. The LPS-induced production of tumour necrosis factor-α was inhibited by AR agonists, and this was also antagonized by butoxamine, and mimicked by salbutamol and terbutaline. The AR agonists also inhibited T-cell proliferation through β2-AR stimulation. This study clearly demonstrated that endogenous catecholamines elicited immunosuppressive effects through β2-AR stimulation, possibly due to down-regulation of the expression of ICAM-1, CD40 and CD14 on monocytes. These results suggested that the sympathetic nervous system might regulate the T-helper cell balance via the peripheral end-effectors of the stress system.

Failure of the gut barrier system enhances liver injury in rats: protection of hepatocytes by gut-derived hepatocyte growth factor

OBJECTIVE

Clinical and experimental studies suggest that impairment of the mucosal barrier system increases gut-derived endotoxin in the portal blood, which causes liver injury. The aim of this study was to elucidate the mechanism of liver injury caused by gut defence failure.

DESIGN

Wistar rats were administered either enteral lipopolysaccharide (LPS) or LPS via the portal vein.

METHODS

Blood samples were collected via the inferior vena cava at necropsy. Serum aspartate transaminase (AST) and alanine transaminase (ALT) were analysed by standard enzymatic procedures and cytokines [tumour necrosis factor-alpha, interleukin (IL)-1beta, interferon-gamma, IL-6 and hepatocyte growth factor (HGF)] were measured by enzyme-linked immunosorbent assay. Livers were removed and snap-frozen in liquid nitrogen. CD14, CD68, Toll-like receptor (TLR) 2, TLR4 and Fas ligand (FasL) were analysed immunohistochemically. Expression of TLR2, TLR4 and CD14 mRNA was determined by reverse transcriptase-polymerase chain reaction.

RESULTS

In enterally-treated rats, AST and ALT were not increased and cytokine levels were under the limits of detection in the absence of a rise in HGF. Enteral administration of LPS increased HGF dose-dependently. Injection of LPS in the portal vein resulted in significant increases in AST, ALT, tumour necrosis factor-alpha, IL-1beta, interferon-gamma and IL-6 levels, but no change in HGF levels. Immunohistochemical analysis revealed that intraportal LPS administration increased CD14, TLR4, CD68 and FasL. Reverse transcriptase-polymerase chain reaction analysis demonstrated that TLR4 mRNA expression was upregulated 0.5 h after intraportal LPS administration.

CONCLUSION

s Our data suggest that Kupffer cell activation mediated by intraportal LPS via TLR4 is involved in liver injury, possibly through both tumour necrosis factor-alpha/IL-1beta and FasL, and that lack of HGF activity in the impaired gut could not counteract liver injury.

Enhanced effects of combined bu-zhong-yi-qi-tang (TJ-41) and interleukin-18 on the production of tumour necrosis factor-alpha and interferon-gamma in human peripheral blood mononuclear cells

Co-stimulatory molecules play important roles in immune responses. We investigated the effect of Bu-Zhong-Yi-Qi-Tang (TJ-41) on the expression of intercellular adhesion molecule-1 (ICAM-1), B7.1 and B7.2 by peripheral blood mononuclear cells stimulated by interleukin-18 (IL-18) using fluorescence-activated cell sorter analysis. TJ-41 increased IL-18-induced ICAM-1 and B7.2 expression, resulting in enhanced production of tumour necrosis factor-alpha and interferon-gamma. These results suggest that TJ-41 enhances IL-18-induced cell-mediated immunity and may enhance host defence mechanisms against pathogens.

Histamine inhibits lipopolysaccharide-induced interleukin (IL)-18 production in human monocytes

Lipopolysaccharide (LPS) is an inducer of interleukin (IL)-18, which in turn plays important roles in immune responses. Previously, we reported that tumor necrosis factor (TNF)-alpha production could be detected in human peripheral blood mononuclear cells (PBMCs) treated with relatively low concentration of LPS (1 ng/ml), but that same concentration of LPS could not induce IL-18 production. In the present study, we found that LPS at relatively high concentrations (10-1000 ng/ml) induced IL-18 production in a concentration-dependent manner both in monocytes isolated from PBMC, and that histamine (10(-7) to 10(-4) M) inhibited IL-18 production induced by LPS. The studies using receptor subtype-selective agonists and antagonists suggested that the effect of histamine was mediated by H2 receptor but not by H1, H3 and H4 receptors. Therefore, the stimulation of H2 receptor might be beneficial in the treatment of sepsis through inhibiting LPS-elicited IL-18.

E-prostanoid (EP)2/EP4 receptor-dependent maturation of human monocyte-derived dendritic cells and induction of helper T2 polarization

Prostaglandin (PG) E(2) induces dendritic cell maturation in cooperation with proinflammatory cytokines [such as tumor necrosis factor (TNF)-alpha and interleukin (IL)-1beta]. To clarify the involvement of E-prostanoid (EP) receptors in the effect of prostaglandin E(2) on human monocyte-derived dendritic cell (MoDC) maturation, we examined the effect of four types of EP receptor-selective agonists on MoDC maturation. PGE(2) as well as 11,15-O-dimethyl prostaglandin (E(2)ONO-AE1-259-01) (EP2 receptor agonist) and ONO-AE1-329 (EP4 receptor agonist) concentration dependently enhanced the expression of CD80, CD86, CD83, and HLA-DR on MoDCs during maturation, especially in the presence of TNF-alpha, whereas 17S-2,5-ethano-6-oxo-17,20-dimethyl prostaglandin E(1) (EP1 receptor agonist) and 16S-9-deoxy-9beta-chloro-15-deoxy-16-hyfroxy-17,17-trimethylene-19,20-didehydro prostaglandin F(2) (EP3 receptor agonist) showed no effect. The maximal effect of ONO-AE1-259-01 was higher than that of ONO-AE1-329; however, the stimulation with ONO-AE1-259-01 was less effective than that with PGE(2). Simultaneous stimulation with both EP receptor agonists produced additive effects and 11-deoxy-PGE(1) (EP2/EP4 receptor mixed agonist) mimicked the effects of PGE(2). Dibutyryl cAMP mimicked the effects of PGE(2), indicating the mediation of PGE(2) action by cAMP. Matured MoDCs induced by PGE(2) or EP2 and/or EP4 receptor agonists showed a decrease in lipopolysaccharide (LPS)-stimulated IL-12p70, IL-6, and IL-10 production. The coculture of naive T cells with matured MoDCs induced under different conditions showed that EP2/EP4-stimulated MoDCs preferentially induced alloresponsive helper T (Th)2 cells. Together, it was concluded that the cooperative stimulation of EP2 and EP4 receptor subtypes by PGE(2) promoted MoDC maturation and inhibited LPS-induced cytokine production in MoDCs. The matured MoDCs under such conditions preferably induced Th2 polarization, indicating the importance of EP2 and EP4 receptors in the determination of Th1/Th2 development of naive T cells.

β2-Adrenergic receptor agonist induces IL-18 production without IL-12 production

Endogenous catecholamine, epinephrine and norepinephrine, and isoproterenol concentration-dependently induced the production of interleukin (IL)-18, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma, and inhibited that of IL-10 in human peripheral blood mononuclear cells (PBMC). All responses by these stimulations were antagonized by the selective beta 2-adrenergic receptor (AR) antagonist, butoxamine, but not by alpha 1-, alpha 2- and beta 1-AR antagonists. The selective beta 2-AR agonists, salbutamol and terbutaline, induced a similar pattern of cytokine production, indicating that the effect of these AR agonists on cytokine production was through beta 2-AR stimulation. Anti-IL-18 Ab or caspase-1 inhibitor prevented all increase/decrease effects, suggesting that IL-18 might affect the production of all other cytokines. While endogenous IL-18 produced by salbutamol and terbutaline reached a sufficient concentration to induce IL-12 production, these beta 2-AR agonists did not induce the production of IL-12 at all. Epinephrine/norepinephrine/isoproterenol/beta 2-AR agonists increased the production of IL-18 in monocytes, but had no effect on IL-12, TNF-alpha, IFN-gamma and IL-10 production. The lack of beta 2-AR-induced effect on IL-12 production was due to a beta 2-AR-induced inhibition of an IL-18-elicited upregulation of both CD40 and CD40 ligand (CD40L/CD154) expressions on monocytes. The sympathetic innervating lymphoid organs may be under the control of beta2-AR stimulation, maintaining the basal cytokine environment in the tissues.

Suppression of allogeneic response by viral IL-10 gene transfer

Th1 cell activation and cytokine production shift the balance between Th1 and Th2, favoring the upregulation of proinflammatory activity that leads to destruction of allogeneic hepatocytes following transplantation. Th2-type cytokines. such as IL-10, have immune regulatory function. The aim of this study was to determine the antirejection efficacy of allogeneic hepatocytes with spheroidal shape (spheroids) genetically modified with viral IL-10 (vIL-10). Allogeneic hepatocyte spheroids, transferred vIL-10 gene by using adenovirus as the vector, were transplanted into the spleen of Nagase's analbuminemic rats (NAR). NAR transplanted with vIL-10-transfected hepatocytes showed an abrupt rise in serum albumin levels that peaked on day 7 and remained at high levels up to day 21 after transplantation. The peak level of albumin on day 7 in vIL-10-transfected NAR was eminently higher than that in nontransfected NAR. Histopathological analysis revealed that in nontransfected NAR hepatocyte spheroids were more or less rejected on day 4, and, in contrast, vIL-10-transfected spheroids were still not rejected on day 14. This protective effect correlated with sustained high vIL-10 level in the splenic vein in NAR transplanted with vIL-10-transfected hepatocyte spheroids, suggesting that vIL-10 secreted from the transplanted hepatocytes induced an active suppression of allogeneic response. This study provides evidence to support the possibility of using vIL-10 gene therapy to prevent allogeneic response in hepatocyte transplantation.