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

Expression of TLR2 and TLR5 in distal ileum of mice with obstructive jaundice and their role in intestinal mucosal injury

INTRODUCTION

The aim was to investigate the expression of TLR2 and TLR5 in the distal ileum of mice with obstructive jaundice (OJ) and their role in intestinal mucosal injury.

MATERIAL AND METHODS

A total of 100 male C57BL/6J mice were randomly assigned to two groups: (I) sham operation (SH); (II) bile duct ligation (BDL). The mice were respectively sacrificed before operation and on the 1^st, 3^rd, 5^th and 7^th days after operation to collect specimens. Various indicators were detected by PCR, immunohistochemistry and other methods.

RESULTS

TLR2 was increased gradually with the extension of OJ time in the BDL group (p < 0.05). However, the changes in the expression of TLR5 were not obvious at different time points. The amount of Bifidobacteria and Lactobacillus showed downward trends in intestinal tract of the BDL group. Furthermore, the amount of Escherichia coli was increased in intestinal tract of the BDL group. The pathological score of intestinal mucosa and the expression of NF-κB increased gradually in the BDL group with the extension of OJ time. There were positive correlations between the pathological score of intestinal mucosa and expressions of TLR2(r = 0.767, p < 0.05) and NF-κB (r = 0.817, p < 0.05) in BDL group. NF-κB expression was positively correlated with TLR2 expression(r = 0.706, p < 0.05).

CONCLUSIONS

Disturbance of intestinal flora caused by OJ could increase the expression of NF-κB via up-regulating the expression of TLR2 to activate the downstream signaling pathway, thus aggravated the injury of intestinal mucosa.

Hepatoprotective effect of ultrasonicated ginseng berry extract on a rat mild bile duct ligation model

Background

The Panax ginseng berry extract (GBE) is well known to have an antidiabetic effect. The aim of this study is to evaluate and investigate the protective effect of ultrasonication-processed P. ginseng berry extract (UGBE) compared with GBE on liver fibrosis induced by mild bile duct ligation (MBDL) model in rats. After ultrasonication process, the composition ratio of ginsenoside in GBE was changed. The component ratio of ginsenosides Rh1, Rh4, Rg2, Rg3, Rk1, Rk3, and F4 in the extract was elevated.

Methods

In this study, the protective effect of the newly developed UGBE was evaluated on hepatotoxicity and neuronal damage in MBDL model. Silymarin (150 mg/kg) was used for positive control. UGBE (100 mg/kg, 250 mg/kg, 500 mg/kg), GBE (250 mg/kg), and silymarin (150 mg/kg) were orally administered for 6 weeks after MBDL surgery.

Results

The MBDL surgery induced severe hepatotoxicity that leads to liver inflammation in rats. Also, the serum ammonia level was increased by MBDL surgery. However, the liver dysfunction of MBDL surgery–operated rats was attenuated by UGBE treatment via myeloid differentiation factor 88-dependent Toll-like receptor 4 signaling pathways.

Conclusion

UGBE has a protective effect on liver fibrosis induced by MBDL in rats through inhibition of the TLR4 signaling pathway in liver.

Resolution of inflammation and mood disorders

Relationship between mood disorders and inflammation is now well-documented, although molecular mechanisms are not understood. Previously mostly pro-inflammatory cytokines of immune system (IL-6, TNF, etc.) were taken into account. However, recent understanding of resolution of inflammation as an active process drew attention to mediators of resolution, which include both proteins and ω-3 and ω-6 polyunsaturated fatty acids derivatives (resolvins, cyclopentenone prostaglandins, etc.). This review takes into account new data on resolution of inflammation and action of mediators of resolution in models of depression. New facts and ideas about mechanisms of chronic inflammation onset are considered in relation to mood disorders. Basic control mechanisms of inflammation at the cellular level and the role of resolution substances in regulation of depression and other mood disorders are discussed. Signaling systems of innate immunity located in non-immune cells and their ability to generate substances that affect an onset of depression are reviewed. A novel hypothesis of depression as a type of abnormal resolution is proposed.

Toll-like receptors: Significance, ligands, signaling pathways, and functions in mammals

This review attempts to cover the implication of the toll-like receptors (TLRs) in controlling immune functions with emphasis on their significance, function, regulation and expression patterns. The tripartite TLRs are type I integral transmembrane receptors that are involved in recognition and conveying of pathogens to the immune system. These paralogs are located on cell surfaces or within endosomes. The TLRs are found to be functionally involved in the recognition of self and non-self-antigens, maturation of DCs and initiation of antigen-specific adaptive immune responses as they bridge the innate and adaptive immunity. Interestingly, they also have a significant role in immunotherapy and vaccination. Signals generated by TLRs are transduced through NFκB signaling and MAP kinases pathway to recruit pro-inflammatory cytokines and co-stimulatory molecules, which promote inflammatory responses. The excess production of these cytokines leads to grave systemic disorders like tumor growth and autoimmune disorders. Hence, regulation of the TLR signaling pathway is necessary to keep the host system safe. Many molecules like LPS, SOCS1, IRAK1, NFκB, and TRAF3 are involved in modulating the TLR pathways to induce appropriate response. Though quantification of these TLRs helps in correlating the magnitude of immune response exhibited by the animal, there are several internal, external, genetic and animal factors that affect their expression patterns. So it can be concluded that any identification based on those expression profiles may lead to improper diagnosis during certain conditions.

Sphingomyelin synthase 2 affects CD14‑associated induction of NF‑κB by lipopolysaccharides in acute lung injury in mice

Lipopolysaccharide (LPS) is the predominant component of the outer membrane of Gram-negative bacteria, which can cause severe inflammation in the body. The acute lung injury (ALI) induced by LPS can cause extensive damage to the lung tissue, the severe stage of which is termed acute respiratory distress syndrome, when multiple organ dysfunction syndrome may appear. There are no effective clinical treatment measures at present. The involvement of cluster of differentiation (CD)14 assists LPS in causing inflammatory reactions, and CD14 and sphingomyelin (SM), located in lipid rafts areas, are closely associated. SM synthase (SMS) is a key enzyme in the synthesis of SM, however, the effect of SMS on the inflammatory pathway involving nuclear factor (NF)‑κB induced by LPS remains to be elucidated. Under the premise of the establishment of an ALI mouse model induced by LPS, the present study established a control group, LPS group and pyrrolidine dithiocarbamate (PDTC; an NF‑κB pathway inhibitor) group. Hematoxylin‑eosin staining, reverse transcription‑quantitative polymerase chain reaction analysis, western blot analysis and thin layer chromatography were used to investigate the mechanism of SMS in ALI. Compared with the control group, the mRNA and protein levels of CD14 were significantly increased (P<0.001; n=5 and P<0.05, n=5), and the activity of SMS and expression of SMS2 were significantly upregulated (P<0.001; n=5 and P<0.05, n=5) in the model group. The increases of SMS2 and CD14 in the PDTC group were less marked, compared with those in the model group (P<0.05; n=5). These findings suggested that the degree of lung injury was reduced during the acute inflammatory reaction when NF‑κB was inhibited, and that the expression of SMS2 may affect the induction of the NF‑κB pathway by LPS through CD14.

Protective effects of Radix Astragali injection on multiple organs of rats with obstructive jaundice

OBJECTIVE

To investigate the protective effects and mechanisms of Radix Astragali Injection on multiple organs of rats with obstructive jaundice (OJ).

METHODS

A total of 180 rats were randomly divided into the sham-operated, model control and treated groups (60 in each group). On 7, 14, 21 and 28 days after operation, the serum contents of alanine aminotransferase (ALT), aspartate aminotransferase (AST), r-glutamyl transpeptidase (r-GT), total bilirubin (TBil), direct bilirubin (DBil), blood urine nitrogen (BUN), and creatinine (CREA) were determined. And the pathological changes of livers, kidneys and lungs, and protein expressions of toll-like receptor-4 (TLR-4) of livers, intercellular adhesion molecule-1 (ICAM-1) of lungs, Bax and nuclear factor-kappa B (NF-κB), as well as apoptotic indexes of multiple organs were observed, respectively.

RESULTS

The pathological severity scores of multiple organs (including livers on 7, 14, 21 and 28 days, kidneys on 14 and 28 days, and lungs on 14 days), serum contents of ALT (14 and 21 days), AST (14 days), TBil (7, 14, 21 and 28 days), DBil (14 and 21 days), BUN (28 days), protein expressions of TLR-4 (in livers, 28 days), Bax (in livers and kidneys, 21 days), and apoptotic indexes in livers (7 and 21 days) in the treated group were significantly lower than those in the model control group (P<0.05 or P<0.01).

CONCLUSION

Radix Astragali Injection exerts protective effects on multiple organs of OJ rats by improving the pathological changes of lung, liver and kidney, decreasing the serum index of hepatic and renal function as well as inhibiting the protein expression of TLR-4 and Bax in the livers and Bax in the kidneys.

Characterization of Toll-like receptor-4 (TLR-4) in the spleen and thymus of Swiss albino mice and its modulation in experimental endotoxemia

Expression of innate immune receptors varies among organs and species and within different strains among the same species; thus, periodic classification of different pattern recognition receptors in the available strains is necessary to initiate different therapeutic approaches to combat inflammation. On characterization of TLR-4 in spleen and thymus of Swiss albino mice—with no reports of TLR-4 expression—induced with endotoxemia, it was found that the mode of expression varied among the organs at both mRNA and protein level in a time-dependent manner. Their functionality was verified by measuring proinflammatory and anti-inflammatory cytokines. In the in vitro study using isolated macrophages and lymphocytes from the same organs, the expression of TLR-4 after a shorter period of LPS stimulation was verified. The results substantiated the potent role of macrophage on LPS challenge compared to lymphocytes. The diverse pattern of TLR-4 expression on different cell population indicated their distinct functional activity in LPS-endotoxemia. It may be hypothesized that the expression patterns of TLR-4 could be different based on the anatomical localization and the varying bacterial milieu or bacterial endotoxin encountered in each anatomical location. Thus, blocking TLR-4 or administering IL-6 or IL-10 might impart protection against endotoxemia in the clinical field.

HGF signaling impacts severity of Pseudomonas aeruginosa keratitis

PURPOSE

To determine whether rapamycin altered corneal growth factor levels to impact severity of Pseudomonas aeruginosa keratitis.

METHODS

BALB/c mice were injected intraperitoneally with rapamycin or PBS and infected with P. aeruginosa. Corneas were harvested and mRNA levels of growth factors (EGF, HGF, FGF-7/KGF), receptors (EGFR, c-met, FGFR-2), and signaling molecules (PI3K, Akt, S6K1, and IGF-1R) tested. ELISA determined HGF/c-met, IGF-1, and Substance P (SP) protein levels. Corneal application of recombinant (r)HGF was assessed by clinical score, photography with a slit lamp, real-time RT-PCR (mRNA for mT0R, IL-10, IL-12, IL-18, PI3KCα, Akt), and ELISA (total and phosphorylated [p]c-met); rIGF-1 effects also were tested by ELISA. In vitro, RAW cells and peritoneal macrophages were stimulated with LPS ± rHGF ± c-met inhibitor (CI) and mTOR mRNA levels tested.

RESULTS

Rapamycin disparately regulated infected corneal mRNA levels of EGF/EGFR and FGF-7/FGFR-2, but HGF/c-met mRNA levels both increased. ELISA confirmed elevated HGF protein. Rapamycin did not change PI3KCα or Akt signaling molecule expression, downregulated S6K1, but upregulated IGF-1R mRNA levels; IGF-1 and SP proteins also were upregulated. After infection, topical rHGF versus PBS increased mRNA levels of IL-12p40, IL-18, PI3KCα, and Akt; mTOR and IL-10 mRNA were downregulated; rIGF-1 increased HGF protein. In vitro, rHGF and LPS lowered RAW cell and macrophage mTOR levels; CI addition restored them.

CONCLUSIONS

Collectively, these data provide evidence that enhanced corneal HGF levels increase signaling through the c-met receptor, decrease mTOR levels, and enhance proinflammatory cytokines, while decreasing anti-inflammatory cytokines, and that HGF signaling is central to disease outcome.

Inhibition of Toll-like receptor 4 suppresses liver injury induced by biliary obstruction and subsequent intraportal lipopolysaccharide injection

The objective of this study was to elucidate the role of Toll-like receptor 4 (TLR4) in liver injury induced by biliary obstruction and subsequent intraportal lipopolysaccharide (LPS) infusion in rats. Biliary obstruction often leads to the development of bacterial translocation. Rats were subjected to either a sham operation (Sham group) or bile duct ligation for 7 days (BDL group). Seven days after each operation, LPS (0.5 μg) was injected through the ileocecal vein. In other experiments, rats that had undergone BDL were pretreated, before LPS challenge, with internal biliary drainage (Drainage group); intravenous TAK-242, a TLR4 inhibitor (TAK group); or intravenous GdCl3, a Kupffer cell deactivator (GdCl3 group). The expression of the TLR4 protein and the number of Kupffer cells in the liver were significantly increased in the BDL group compared with the Sham group. These changes were normalized after biliary drainage. The expression of TLR4 colocalized with Kupffer cells, which was confirmed by double immunostaining. Serum levels of liver enzymes and proinflammatory cytokines after intraportal LPS injection were significantly higher in the BDL group than in the Sham group. However, pretreatment with TAK-242 or GdCl3 strongly attenuated these changes to levels similar to those seen with biliary drainage. These results imply that blocking TLR4 signaling effectively attenuates liver damage to the same level as that observed with biliary drainage in rats with BDL and subsequent intraportal LPS infusion. TAK-242 treatment may be used for patients who are susceptible to liver damage by biliary obstruction and endotoxemia.

Advances in cholangiocyte immunobiology

Cholangiocytes, or bile duct epithelia, were once thought to be the simple lining of the conduit system comprising the intra- and extrahepatic bile ducts. Growing experimental evidence demonstrated that cholangiocytes are in fact the first line of defense of the biliary system against foreign substances. Experimental advances in recent years have unveiled previously unknown roles of cholangiocytes in both innate and adaptive immune responses. Cholangiocytes can release inflammatory modulators in a regulated fashion. Moreover, they express specialized pattern-recognizing molecules that identify microbial components and activate intracellular signaling cascades leading to a variety of downstream responses. The cytokines secreted by cholangiocytes, in conjunction with the adhesion molecules expressed on their surface, play a role in recruitment, localization, and modulation of immune responses in the liver and biliary tract. Cholangiocyte survival and function is further modulated by cytokines and inflammatory mediators secreted by immune cells and cholangiocytes themselves. Because cholangiocytes act as professional APCs via expression of major histocompatibility complex antigens and secrete antimicrobial peptides in bile, their role in response to biliary infection is critical. Finally, because cholangiocytes release mediators critical to myofibroblastic differentiation of portal fibroblasts and hepatic stellate cells, cholangiocytes may be essential in the pathogenesis of biliary cirrhosis.

Long-lasting effect of infant rats endotoxemia on heat shock protein 60 in the pancreatic acinar cells: involvement of toll-like receptor 4

Introduction. Lipopolysaccharide endotoxin (LPS) is responsible for septic shock and multiorgan failure, but pretreatment of rats with low doses of LPS reduced pancreatic acute damage. Aim. We investigated the effects of the endotoxemia induced in the early period of life on Toll-like receptor 4 (TLR4), heat shock protein 60 (HSP60) and proapoptotic Bax, caspase-9 and -3 or antiapoptotic Bcl-2 protein expression in the pancreatic acinar cells of adult animals. Material and Methods. Newborn rats (25 g) were injected with endotoxin (Escherichia coli) for 5 consecutive days. Two months later, pancreatic acinar cells were isolated from all groups of animals and subjected to caerulein stimulation (10⁻⁸ M). Protein expression was assessed employing Western blot. For detection of apoptosis we have employed DNA fragmentation ladder assay. Results. Preconditioning of newborn rats with LPS increased TLR4, Caspase-9 and -3 levels, but failed to affect basal expression of HSP60, Bax, and Bcl-2. Subsequent caerulein stimulation increased TLR4, Bcl-2, and caspases, but diminished HSP60 and Bax proteins in pancreatic acinar cells. Endotoxemia dose-dependently increased TLR4, Bax, HSP60, and both caspases protein signals in the pancreatic acini, further inhibiting antiapoptotic Bcl-2. Conclusions. Endotoxemia promoted the induction of HSP60 via TLR4 in the infant rats and participated in the LPS-dependent pancreatic tissue protection against acute damage.

Improvement of sepsis by hepatocyte growth factor, an anti-inflammatory regulator: emerging insights and therapeutic potential

Sepsis-induced multiple organ failure (MOF) is the most frequent lethal disease in intensive care units. Thus, it is important to elucidate the self-defensive mechanisms of sepsis-induced MOF. Hepatocyte growth factor (HGF) is now recognized as an organotrophic factor, which is essential for organogenesis during embryonic growth and regeneration in adulthood. HGF production is enhanced in response to infectious challenges, but the increase in endogenous HGF levels is transient and insufficient, with a time lag between tissue injuries and HGF upregulation, during progression of septic MOF. Thus, administration of active-formed HGF might be a new candidate for therapeutic development of MOF. HGF has an ability to target endotoxin-challenged macrophages and inhibits the upregulation of inflammatory cytokines through nuclear factor-κB-inactivated mechanisms. HGF also targets the endothelium and epithelium of various organs to suppress local inflammation, coagulation, and apoptotic death. This paper summarizes the novel mechanisms of HGF for attenuating sepsis-related pathological conditions with a focus on sepsis-induced MOF.

Glucocorticoid modulates high-mobility group box 1 expression and Toll-like receptor activation in obstructive jaundice

BACKGROUND

Obstructive jaundice is associated with bacterial translocation and inflammatory cytokine induction. It is unknown if toll-like receptors (TLRs) and their upstream molecule high mobility group box-1 (HMGB1) are involved in the pathogenetic mechanism and if glucocorticoid is effective in modulating the process.

MATERIALS AND METHODS

A rat model of cholestasis by ligation of the extrahepatic bile duct (BDL) for 2 wk was created. TLRs, interferon regulatory factors (IRFs), IL-6, IL-8, antimicrobial peptide β-defensin, and cathelicidin, as well as HMGB1 expressions were studied by using real-time quantitative reverse transcription-polymerase chain reaction, immunohistochemistry, Western blotting, and enzyme-linked immunosorbent assay (ELISA). Glucocorticoid treatment was applied to a group of BDL rats.

RESULTS

Obstructive jaundice for 2 wk was associated with significant up-regulation of TLR1, 2, 4, 6, 7, and 9 mRNA expressions. There were significant increases of liver IRF5, IL-6, and β-defensin 1 mRNA levels in the BDL rats than in the sham and nonoperative control rats, which were associated with significant increase of immunoreactive IRF5 protein staining in the nucleus of Kupffer cells and neutrophils. Hepatic HMGB1 expression and release into serum were significantly elevated in the cholestatic rats than in the sham and control rats. Glucocorticoid treatment significantly decreased hepatic HMGB1 expression and release into serum, which was associated with significantly decreased hepatic TLR4 mRNA expression in the cholestatic rats.

CONCLUSIONS

The results indicate that obstructive jaundice may induce hepatic HMGB1 expression with activation of TLR4 and a number of downstream signaling molecules, which can be reversed by glucocorticoid administration.

TLRs in Hepatic Cellular Crosstalk

Toll-like receptors (TLRs) are expressed on all major subsets of liver cells. Both exogenous ligands derived from pathogens, and endogenous ligands that are products of cellular injury, engage these receptors and activate aspects of innate immunity. These receptors play a role in viral and parasitic infections of the liver, in ischemia-reperfusion injury, and in toxic liver damage, promoting antipathogen immunity but also hepatocellular injury and fibrogenesis. However, TLRs may also participate in negative feedback that limits tissue injury. In the complex environment of the liver, TLRs participate in pathologic cascades involving multiple cell types, manifesting their effects both through cell-autonomous actions, and via cellular crosstalk. In this paper we survey the involvement of TLRs in these diverse processes.

Significance of MD-2 and MD-2B expression in rat liver during acute cholangitis

AIM

To investigate the expression of myeloid differentiation protein-2 (MD-2), MD-2B (a splicing isoform of MD-2 that can block Toll-like receptor 4 (TLR4)/MD-2 LPS-mediated signal transduction) and TLR4 in the liver of acute cholangitis rats.

METHODS

Male Sprague-Dawley rats (SPF level) were randomly divided into four groups: (A) sham-operated group; (B) simple common bile duct ligation group; (C) acute cholangitis group; and (D) acute cholangitis anti-TLR4 intervention group (n = 25 per group). Rat liver tissue samples were used to detect TLR4, MD-2 and MD-2B mRNA expression by fluorescence quantitative PCR in parallel with pathological changes.

RESULTS

In acute cholangitis, liver TLR4 and MD-2 mRNA expression levels at 6, 12, 24, 48 and 72 h were gradually up-regulated but MD-2B mRNA expression gradually down-regulated (P < 0.05). After TLR4 antibody treatment, TLR4 and MD-2 mRNA expression were lower compared with the acute cholangitis group (P < 0.05). However, MD-2B mRNA expression was higher than in the acute cholangitis group (P < 0.05). MD-2 and TLR4 mRNA expressions were positively correlated (r = 0.94981, P < 0.05) and MD-2B mRNA expression was negatively correlated with MD-2 and TLR4 mRNA (r = -0.89031, -0.88997, P < 0.05).

CONCLUSION

In acute cholangitis, MD-2 plays an important role in the process of TLR4- mediated inflammatory response to liver injury while MD-2B plays a negative regulatory role.

Effects of Salvia miltiorrhizae on ICAM-1, TLR4, NF-kappaB and Bax proteins expression in multiple organs of rats with severe acute pancreatitis or obstructive jaundice

To observe the protective effects of Salvia miltiorrhizae injection on multiple organs of rats with SAP or OJ. Two hundred eighty-eight rats were used for SAP-associated experiments and OJ-associated experiments. The rats were randomly divided into sham-operated, model control and treated group. According to the different time points after operation, the SAP rats in each group were subdivided into 3, 6 and 12 h groups while the OJ rats were divided into 7, 14, 21 and 28 days groups. The mortality rates, pathological changes and ICAM-1 (only in lung), TLR4 (only in liver), Bax and NF-kappaB proteins expression in multiple organs (liver, kidney, lung, intestinal mucosa, spleen, thymus and lymph nodes) were observed, respectively. The mortality rates of treated groups decreased in both SAP and OJ experiments. Compared to model control group, the pathological changes can be seen in treated groups including; (1) the pathological changes of multiple organs in SAP and OJ experiments were improved, the pathological severity scores of kidney (at 6 h), intestinal mucosa (at 12 h), spleen (at 6 and 12 h), thymus (at 3 and 6 h) and lymph nodes (at 3 and 6 h) in SAP experiment and of liver (on 21 and 28 days), lung (21 days), intestinal mucosa (on 21 and 28 days) and spleen (on 21 and 28 days) in OJ experiment significantly declined (P < 0.05 or P < 0.01); (2) the positive rate of Bax protein in pancreas (at 3 h) and liver (on 6 and 12 h) in SAP experiment and in liver (on 28 days), kidney (on 21 days), and thymus (on 28 days) in OJ experiment were significantly lower (P < 0.05 or P < 0.01); (3) the positive rate of NF-kappaB in liver (at 12 h) and kidney (at 6 h) in SAP experiment and in liver (on 21 days), kidney (on 28 days), intestinal mucosa (on 28 days) and thymus (on 14 days) in OJ experiment significantly decreased (P < 0.05). (4) the positive rate of ICAM-1 in lungs (at 12 h) in SAP experiment was significantly less (P < 0.05). Salvia miltiorrhizae injection can protect multiple organs of SAP or OJ rats and inhibit the expression of ICAM-1, TLR4, NF-kappaB and regulate Bax proteins. Salvia miltiorrhizae may relieve the inflammation response and enhance the immunity function of SAP and OJ rats.

Effect of salvia miltiorrhizae on the expressions of TLR4 protein in the liver of rats with SAP or OJ

To investigate the effect of salvia miltiorrhizae on the expressions of TLR4 protein in the liver of rats with severe acute pancreatitis (SAP) and obstructive jaundice (OJ), and explore the protective mechanism of salvia miltiorrhizae on the liver of rats. A total of 288 mice was used in SAP- (n = 108) and OJ-associated experiments (n = 180). The rats were randomly divided into sham-operated, model control and treated group. Based on the different time points after operation, these groups were subdivided into 3, 6 and 12 h subgroups (SAP rats, n = 12) or 7, 14, 21 and 28 days subgroups (OJ rats, n = 15). At the corresponding time points after operation, blood and liver specimens were collected to determine the contents of endotoxin and TNF-alpha in the blood as well as the expression levels of TLR4 protein in the liver. Compared with the corresponding model control group, though the number of dead SAP or OJ rats in the treated group declined, no statistical difference was noted; The levels of plasma endotoxin in SAP (at 6 and 12 h) or OJ rats in the treated group decreased significantly (P < 0.001 and P < 0.01, respectively); The levels of serum TNF-alpha in SAP (at 12 h) or OJ rats (on 14 days) declined (P < 0.001 and P < 0.01, respectively); The staining intensity as well as the product of staining intensity and positive rate of TRL4 protein only significantly declined on 7 and 28 days in OJ rats (P < 0.01). On 7 days, treated group in positive rate of TLR4 protein were significantly lower than that in model control group (P < 0.01). The pathological changes in different treated groups of SAP and OJ rats were improved. Salvia miltiorrhizae is able to reduce the levels of plasma endotoxin and inhibit effectively the expressions of TLR4 protein in the liver of SAP or OJ rats, thereby decreasing inflammatory reaction and exerting protective effect on liver function.

Changes of serum cytokines and expression of inducible nitric oxide synthase mRNA by Kupffer cells after relief from obstructive jaundice in rats

AIMS

To investigate the changes of serum endotoxin, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) expression by Kupffer cells after relief of obstructive jaundice (OJ) by internal biliary drainage (ID) and external biliary drainage (ED) in rats.

MATERIALS AND METHODS

Forty eight adult Sprague Dawley rats were randomly assigned to four groups: OJ, ID, ED and sham operation (SH). Inducible nitric oxide synthase mRNA by the Kupffer cells was detected by reverse transcription polymerase chain reaction. The serum TNF-alpha and IL-6 were measured by enzyme linked immunosorbent assay and endotoxin by kinetic turbidimetric limulus tests.

RESULTS

Serum endotoxin, IL-6 and TNF-alpha levels were significantly elevated in OJ rats compared to that of SH rats (P < 0.01). After relief from OJ, the elevated endotoxin, IL-6 and TNF-alpha levels could be significantly depressed by ID (P < 0.01). However, the serum IL-6 level was increased in ED rats (P < 0.05) and the TNF-alpha level was not depressed by ED. Expression of iNOS mRNA by Kupffer cells was markedly stronger in the OJ group than in the SH group (P = 0.005). After relief from OJ, the iNOS mRNA expression was suppressed by ID (P = 0.139, ID vs OJ). However, the iNOS mRNA expression was promoted by ED (P = 0.321 ED vs OJ; P = 0.016 ED vs SH).

CONCLUSIONS

The levels of serum endotoxin, TNF-alpha and IL-6 and the expression of iNOS mRNA by Kupffer cells were increased in rats with obstructive jaundice. Internal biliary drainage could entirely reverse the changes, but external drainage only partially did.

The immunobiology of cholangiocytes

Cholangiocytes, the epithelial cells lining bile ducts, provide the first line of defense against lumenal microbes in the biliary system. Recent advances in biliary immunity indicate that cholangiocytes express a variety of pathogen-recognition receptors and can activate a set of intracellular signaling cascades to initiate a profound antimicrobial defense, including release of proinflammatory cytokines and chemokines, production of antimicrobial peptides and maintenance of biliary epithelial integrity. Cholangiocytes also interact with other cell types in the liver (for example, lymphocytes and Kupffer cells) through expression and release of adhesion molecules and immune mediators. Subsequently, through an intricate feedback mechanism involving both epithelial and other liver cells, a set of intracellular signaling pathways are activated to regulate the functional state of cholangiocyte responses during microbial infection. Thus, cholangiocytes are actively involved in mucosal immunity of the biliary system and represent a fine-tuned, integral component of liver immunity.

Oral insulin up-regulates Toll-like receptor 4 expression and enhances intestinal recovery following lipopolysaccharide-induced gut injury in a rat

In the present study, we evaluated the protective effect of oral insulin (OI) on intestinal mucosa following lipopolysaccharide-induced intestinal damage in a rat. Male Sprague-Dawley rats were divided into three experimental groups: Sham rats, LPS-rats that were treated with lipopolysaccharide (LPS), and LPS-INS rats that were treated with OI given in drinking water 72 h before and following injection of LPS. Intestinal structural changes, enterocyte proliferation, enterocyte apoptosis, and mucosal expression of Toll-like receptor 4 (TLR4) were determined 24 h after the last LPS injection. LPS-INS animals showed a significantly greater bowel and mucosal weight in jejunum and ileum, mucosal DNA and protein in jejunum and ileum, villus height in ileum, crypt depth in jejunum and ileum, cell proliferation rates in jejunum, and significantly lower apoptotic index in ileum compared to LPS- animals. LPS rats demonstrated 50% increase in TLR4 expression in jejunum compared to sham animals. Treatment with OI resulted in a three-fold increase in TLR4 expression in jejunum, compared to LPS animals. In conclusion, OI improves intestinal recovery after LPS endotoxemia in a rat.

Hyperbilirubinemia: a risk factor for infection in the surgical intensive care unit

BACKGROUND

Hyperbilirubinemia in intensive care unit (ICU) patients is common. We hypothesized that hyperbilirubinemia in the surgical ICU predisposes patients to infection.

METHODS

Patients with bilirubin < or = 3 mg/dL were compared to patients with bilirubin > 3 mg/dL. We then compared the low bilirubin patients to high bilirubin patients who developed infection after their hyperbilirubinemia.

RESULTS

There were 1,620 infections in 5,712 patients with low bilirubin (28%), compared with 284 in 409 patients in the high bilirubin group (69%, P < .001). After removing the patients in whom hyperbilirubinemia developed after infection, we found infection in 156 of 281 remaining patients (56%, P < .001). This group had a 3-fold increased risk of infection compared with low bilirubin (odds ratio [OR] 3.17, 95% confidence interval [CI] 2.48-4.03, P < .001).

CONCLUSIONS

There is an increased susceptibility to infection among jaundiced surgical ICU (SICU) patients that persists even when sepsis-related hyperbilirubinemia patients are excluded.

Role of toll-like receptor 4 in the pathophysiology of severe acute pancreatitis in mice

PURPOSE

Multiple organ dysfunction and infection are major contributors to the high mortality associated with severe acute pancreatitis (SAP). Toll-like receptor 4 (TLR4) recognizes the lipopolysaccharide of gram-negative bacilli and is involved in inflammatory response and host defense. We examined the effects of TLR4-deficiency in SAP in mice.

METHODS

Closed duodenal loop-induced pancreatitis was induced in C3H/HeN (wild-type) and C3H/HeJ (TLR4-deficient) mice. We compared the severity of pancreatitis, liver and kidney dysfunction, and bacterial translocation to the pancreas between the two types of mice 12 h after the induction of SAP.

RESULTS

The severity of pancreatitis was similar in the two types of mice. The TLR4-deficient mice had significantly lower serum levels of aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, and creatinine; significantly lower serum levels of interleukin-1 and tumor necrosis factor; reduced apoptosis of the liver and kidney; and a significantly higher rate of positive gram-negative bacterial cultures of the pancreas. TLR4 protein expression in the liver, kidney, and small intestine was increased 4 h after the induction of SAP, and decreased 12 h after the induction of SAP.

CONCLUSIONS

TLR4 is implicated in the mechanism of organ dysfunction and bacterial translocation in SAP, and TLR4 may trigger the inflammatory response and function defensively against infection.

Jaundice in the intensive care unit

Hyperbilirubinemia, or jaundice, is common in the ICU, with incidence up to 40% among critically ill patients. Unfortunately, it is poorly understood in the critically ill, and too often presents a diagnostic dilemma to the ICU physician. Causes of jaundice in the ICU are multiple; the etiology in any given patient, multifactorial. Acute jaundice can be a harbinger or marker of sepsis, multisystem organ failure (MSOF), or a reflection of transient hypotension (shock liver), right-sided heart failure, the metabolic breakdown of red blood cells, or pharmacologic toxicity. Acute ICU jaundice is best divided into obstructive and nonobstructive. This stratification directs subsequent management and therapeutic decisions.