Enhanced monocyte activation and hepatotoxicity in response to endotoxin in portal hypertension

Rifaximin Improves Liver Functional Reserve by Regulating Systemic Inflammation

Rifaximin, a non-absorbable antibiotic, has been demonstrated to be effective against hepatic encephalopathy (HE); however, its efficacy on liver functional reserve remains unknown. Here, we evaluated the efficacy of rifaximin on the liver functional reserve and serological inflammation-based markers in patients with cirrhosis. A retrospective study was conducted on patients who received rifaximin for more than three months at our hospital between November 2016 and October 2021. The recurrence and grade of HE, serological ammonia levels, Child–Pugh score (CPS), and serological inflammation-based markers such as the neutrophil–lymphocyte ratio (NLR), lymphocyte–monocyte ratio (LMR), platelet–lymphocyte ratio (PLR), C-reactive protein (CRP), and CRP to albumin ratio (CAR) were evaluated. The correlations between serological inflammation-based markers and liver functional reserve were evaluated. HE grades, serum ammonia levels, and inflammation-based markers significantly improved at three months compared with those at baseline. Patients with improved albumin levels showed significantly higher CRP improvement rates at both 3 and 12 months. Patients with an improvement in CAR at 3 months demonstrated a significant improvement in CPS at 12 months. Rifaximin improved the liver functional reserve in patients with cirrhosis. Improvements in inflammation-based markers, particularly CRP and albumin, may be involved in this process.

Soluble Urokinase Plasminogen Activator Receptor Levels Are Associated with Severity of Fibrosis in Patients with Primary Sclerosing Cholangitis

The soluble urokinase-type plasminogen activator receptor (suPAR) has evolved as a useful biomarker for different entities of chronic liver disease. However, its role in patients with primary sclerosing cholangitis (PSC) is obscure. We analyzed plasma levels of suPAR in 84 patients with PSC and compared them to 68 patients with inflammatory bowel disease (IBD) without PSC and to 40 healthy controls. Results are correlated with clinical records. suPAR concentrations were elevated in patients with PSC compared to patients with IBD only and to healthy controls (p < 0.001). Elevated suPAR levels were associated with the presence of liver cirrhosis (p < 0.001) and signs of portal hypertension (p < 0.001). suPAR revealed a high accuracy for the discrimination of the presence of liver cirrhosis comparable to previously validated noninvasive fibrosis markers (area under the curve (AUC) 0.802 (95%CI: 0.702−0.902)). Further, we demonstrated that suPAR levels may indicate the presence of acute cholangitis episodes (p < 0.001). Finally, despite the high proportion of PSC patients with IBD, presence of IBD and its disease activity did not influence circulating suPAR levels. suPAR represents a previously unrecognized biomarker for diagnosis and liver cirrhosis detection in patients with PSC. However, it does not appear to be confounded by intestinal inflammation in the context of IBD.

Electroacupuncture Ameliorates Intestinal Barrier Destruction in Mice With Bile Duct Ligation-Induced Liver Injury by Activating the Cholinergic Anti-Inflammatory Pathway

OBJECTIVES

Electroacupuncture (EA) at Zusanli (ST36) can attenuate inflammation in different rodent models. However, the therapeutic mechanisms underlying its action in inhibiting intestinal barrier destruction and liver injury in cholestasis mice have not been clarified. This study aimed at investigating whether EA at ST36 could activate the cholinergic anti-inflammatory pathway to inhibit intestinal barrier destruction and liver injury in cholestasis mice.

MATERIALS AND METHODS

Male Hmox1^floxp/floxp C57BL/6 mice were randomized and subjected to a sham or bile duct ligation (BDL) surgery. The BDL mice were randomized and treated with, or without (BDL group), sham EA at ST36 (BDL+sham-ST36) or EA at ST36 (BDL+ST36), or received α-bungarotoxin (α-BGT), a specific inhibitor of nicotinic acetylcholine receptor α7 subunit (α7nAChR), before stimulation (BDL+ST36+α-BGT). These mice, together with a group of intestine-specific heme oxygenase-1 (HO-1) knockout (KO) Villin-Cre-HO-1^-/- mice, were monitored for their body weights before and 14 days after BDL. The levels of plasma cytokines and liver injury-related alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured by enzyme-linked immunoassay, and pathological changes in the intestinal mucosa and liver fibrosis as well as intestinal barrier permeability in individual mice were examined by histology and immunohistochemistry. The levels of α7nAChR, HO-1, ZO-1, Occludin, Claudin-1, and NF-κBp65 expression and NF-κBp65 phosphorylation in intestinal tissues were quantified.

RESULTS

Compared with the sham group, BDL significantly increased the levels of plasma interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor α, ALT, and AST and caused intestinal mucosal damages, high permeability, and liver fibrosis in mice, which were remarkably mitigated, except for further increased levels of plasma IL-10 in the BDL+ST36 group of mice. Similarly, EA at ST36 significantly up-regulated α7nAChR and HO-1 expression; mitigated the BDL-decreased ZO-1, Occludin, and Claudin-1 expression; and attenuated the BDL-increased NF-κBp65 phosphorylation in intestinal tissues of mice. The therapeutic effects of EA at ST36 were significantly abrogated by pretreatment with α-BGT or HO-1 KO.

CONCLUSION

EA at ST36 inhibits the BDL-induced intestinal mucosal damage and liver fibrosis by activating the HO-1 cholinergic anti-inflammatory pathway in intestinal tissues of mice.

Soluble CD163 for Prediction of High-Risk Esophageal Varices and Variceal Hemorrhage in Patients with Liver Cirrhosis

<b><i>Introduction:</i></b> Activation of hepatic macrophages in liver disease is pathogenically related to portal hypertension (PH). Soluble CD163 (sCD163) is shed in blood by activated macrophages and may predict PH progression noninvasively. This study was designed to investigate the relation of serum sCD163 to the grade and bleeding risk of esophageal varices (EV) and its role for prediction of variceal hemorrhage (VH). <b><i>Methods:</i></b> The study included cirrhotic patients divided into 3 groups: patients who presented with acute upper gastrointestinal bleeding (UGIB) proved to originate from EV on endoscopy, patients without any history of UGIB but who revealed EV on surveillance endoscopy, and patients without endoscopic evidence of varices. Variceal grade and risk signs and bleeding stigmata were noted simultaneously with measurement of serum sCD163 concentration. <b><i>Results:</i></b> Serum sCD163 concentration showed a significant increase in cirrhotic patients compared to healthy subjects (<i>p</i> &#x3c; 0.001) with a stepwise increase among the group without varices, nonbleeder group, and bleeder group sequentially. Serum sCD163 levels correlated positively with the variceal grade and risk signs in both the bleeder and nonbleeder groups (<i>p</i> = 0.002, <i>p</i> &#x3c; 0.001 and <i>p</i> = 0.004, <i>p</i> &#x3c; 0.001, respectively). Serum sCD163 at a cutoff value of 3.6 mg/L performed significantly for prediction of EV presence (AUC = 0.888). Serum sCD163 at a cutoff value &#x3e;4 mg/L significantly predicted large-size and high-risk EV (AUC = 0.910 and AUC = 0.939, respectively) and the index bleed risk (AUC = 0.977). Serum sCD163 at a cutoff value &#x3e;4.05 mg/L modestly discriminated bleeding EV from those that had never bled (AUC = 0.811). <b><i>Conclusions:</i></b> Serum sCD163 levels accurately predicted high-grade and high-risk EV and could help plan for primary prophylaxis. However, it modestly identified VH occurrence, and endoscopy would be required to make a definitive diagnosis.

Decreased monocyte shedding of the migration inhibitor soluble CD18 in alcoholic hepatitis

OBJECTIVES

During alcoholic hepatitis (AH) monocytes traverse the vascular boundaries and massively invade the liver. In principle, tissue extravasation can be limited through shedding of CD18 integrins from leukocytes, including monocytes. The soluble (s) product sCD18 conceals adhesion receptors on the endothelium, which reduces monocyte extravasation. In AH, monocytes are dysfunctional, but whether this involves their self-generated anti-migration is unknown. Our aim was, therefore, to investigate monocyte CD18 dynamics in AH.

METHODS

We studied 50 AH patients and 20 healthy controls. We measured monocyte expression and conformational activation of CD18, plasma (P)-sCD18, stimulated in vitro CD18 shedding and P-sCD18 in a short-term chronic-binge mouse model.

RESULTS

AH-derived monocytes had a 30-60% higher expression of active CD18 receptors (p < 0.01), but the sCD18 concentration per monocyte was reduced in vivo by 30% and in vitro by 120% (p < 0.01). Ethanol reduced the in vitro shedding of CD18 in the patients only. TNFα increased sCD18 concentration per monocyte, but less so in the patients (p < 0.04). P-sCD18 per monocyte was inversely related to disease severity. In early alcoholic liver disease, P-sCD18 was decreased in the mouse model.

CONCLUSIONS

The monocyte CD18 integrins are highly activated in AH and the single monocyte shedding of CD18 was decreased favoring tissue extravasation. Alcohol in itself and altered monocyte responsiveness to TNFα may explain this lowered shedding.

TRANSLATIONAL IMPACT

The contribution of this mechanism to the excessive monocyte liver infiltration in AH should be further explored as it may serve as a potential therapeutic target to limit liver inflammation.

The macrophage activation marker sCD163 combined with markers of the Enhanced Liver Fibrosis (ELF) score predicts clinically significant portal hypertension in patients with cirrhosis

BACKGROUND

Noninvasive identification of significant portal hypertension in patients with cirrhosis is needed in hepatology practice.

AIM

To investigate whether the combination of sCD163 as a hepatic inflammation marker and the fibrosis markers of the Enhanced Liver Fibrosis score (ELF) can predict portal hypertension in patients with cirrhosis.

METHODS

We measured sCD163 and the ELF components (hyaluronic acid, tissue inhibitor of metalloproteinase-1 and procollagen-III aminopeptide) in two separate cohorts of cirrhosis patients that underwent hepatic vein catheterisation. To test the predictive accuracy we developed a CD163-fibrosis portal hypertension score in an estimation cohort (n = 80) and validated the score in an independent cohort (n = 80). A HVPG ≥10 mmHg was considered clinically significant.

RESULTS

Both sCD163 and the ELF components increased in a stepwise manner with the patients' Child-Pugh score (P < 0.001, all), and also with increasing HVPG (P < 0.001). receiver operator characteristics (ROC) analyses showed that each one of the individual components predicted a HVPG >10 mmHg with AUROC's of approximately 0.80. The combined score optimised by logistic regression analyses improved the AUROC to 0.91 in the estimation cohort and 0.90 in the validation cohort. Furthermore, a high value of the combined score was associated with a high short-term mortality.

CONCLUSIONS

The combination of the macrophage activation marker sCD163 and the fibrosis markers predicted significant portal hypertension in patients with cirrhosis. This score may prove useful for screening purposes and highlights the importance of both the inflammatory and the fibrotic components of cirrhotic portal hypertension.

Metabolomics changes in a rat model of obstructive jaundice: mapping to metabolism of amino acids, carbohydrates and lipids as well as oxidative stress

The study examined the global metabolic and some biochemical changes in rats with cholestasis induced by bile duct ligation (BDL). Serum samples were collected in male Wistar rats with BDL (n = 8) and sham surgery (n = 8) at day 3 after surgery for metabolomics analysis using a combination of reversed phase chromatography and hydrophilic interaction chromatography (HILIC) and quadrupole-time-of-flight mass spectrometry (Q-TOF MS). The serum levels of malondialdehyde (MDA), total antioxidative capacity (T-AOC), glutathione (GSH) and glutathione disulfide (GSSG), the activities of superoxide dismutase (SOD) and glutathion peroxidase (GSH-Px) were measured to estimate the oxidative stress state. Key changes after BDL included increased levels of l-phenylalanine, l-glutamate, l-tyrosine, kynurenine, l-lactic acid, LysoPC^c (14:0), glycine and succinic acid and decreased levels of l-valine, PC^b (19:0/0:0), taurine, palmitic acid, l-isoleucine and citric acid metabolism products. And treatment with BDL significantly decreased the levels of GSH, T-AOC as well as SOD, GSH-Px activities, and upregulated MDA levels. The changes could be mapped to metabolism of amino acids and lipids, Krebs cycle and glycolysis, as well as increased oxidative stress and decreased antioxidant capability. Our study indicated that BDL induces major changes in the metabolism of all 3 major energy substances, as well as oxidative stress.

Pathogenesis of hepatic encephalopathy: role of ammonia and systemic inflammation

The syndrome we refer to as Hepatic Encephalopathy (HE) was first characterized by a team of Nobel Prize winning physiologists led by Pavlov and Nencki at the Imperial Institute of Experimental Medicine in Russia in the 1890's. This focused upon the key observation that performing a portocaval shunt, which bypassed nitrogen-rich blood away from the liver, induced elevated blood and brain ammonia concentrations in association with profound neurobehavioral changes. There exists however a spectrum of metabolic encephalopathies attributable to a variety (or even absence) of liver hepatocellular dysfunctions and it is this spectrum rather than a single disease entity that has come to be defined as HE. Differences in the underlying pathophysiology, treatment responses and outcomes can therefore be highly variable between acute and chronic HE. The term also fails to articulate quite how systemic the syndrome of HE can be and how it can be influenced by the gastrointestinal, renal, nervous, or immune systems without any change in background liver function. The pathogenesis of HE therefore encapsulates a complex network of interdependent organ systems which as yet remain poorly characterized. There is nonetheless a growing recognition that there is a complex but influential synergistic relationship between ammonia, inflammation (sterile and non-sterile) and oxidative stress in the pathogenesis HE which develops in an environment of functional immunoparesis in patients with liver dysfunction. Therapeutic strategies are thus moving further away from the traditional specialty of hepatology and more towards novel immune and inflammatory targets which will be discussed in this review.

Recent insights into the pathogenesis of hepatic encephalopathy and treatments

Hepatic encephalopathy (HE) encompasses a spectrum of neuropsychiatric disorders related to liver failure. The development of HE can have a profound impact on mortality as well as quality of life for patients and carers. Ammonia is central in the disease process contributing to alteration in neurotransmission, oxidative stress, and cerebral edema and astrocyte swelling in acute liver failure. Inflammation in the presence of ammonia coactively worsens HE. Inflammation can result from hyperammonemic responses, endotoxemia, innate immune dysfunction or concurrent infection. This review summarizes the current processes implicated in the pathogenesis of HE, as well as current and potential treatments. Treatments currently focus on reducing inflammation and/or blood ammonia levels and provide varying degrees of success. Optimization of current treatments and initial testing of novel therapies will provide the basis of improvement of care in the near future.

Soluble urokinase plasminogen activator receptor is compartmentally regulated in decompensated cirrhosis and indicates immune activation and short-term mortality

OBJECTIVE

Patients with decompensated cirrhosis are susceptible to bacterial infections, which are associated with organ failure and a high mortality rate. Reliable biomarkers are needed to identify patients who require intensified treatment. Our objective was to study the regulation and prognostic relevance of elevated concentrations of soluble urokinase plasminogen activator receptor (suPAR) in patients with advanced cirrhosis.

DESIGN, SETTING AND PARTICIPANTS

We examined the associations between serum and ascitic fluid (AF) suPAR and liver function, bacterial infection, and short-term mortality in 162 consecutive patients with decompensated cirrhosis undergoing diagnostic paracentesis in a tertiary health care centre in Germany.

MAIN OUTCOME MEASURE

Twenty-eight-day mortality.

RESULTS

Circulating suPAR levels were increased in patients with decompensated cirrhosis and correlated with the severity of liver dysfunction and systemic inflammation but were not indicative of bacterial infection. Circulating suPAR levels >14.4 ng mL(-1) predicted 28-day mortality, even after adjustment for liver function and confounders [HR = 3.05 (1.35-6.90); P = 0.0076] equal to the MELD score (AUC = 0.71; 95% CI = 0.61-0.81; P < 0.001). Cut-off levels derived from cohorts without liver disease were not applicable due to the low specificity. AF suPAR levels were elevated during spontaneous bacterial peritonitis (SBP), but not during episodes in which bacteria or bacterial DNA was translocated into the ascites. AF suPAR levels correlated poorly with systemic suPAR but were associated with a more severe course of SBP and a worse outcome. In vitro experiments revealed that monocytes, and to a lesser extent neutrophils, secrete suPAR after Toll-like-receptor ligation, which led to rapid urokinase plasminogen activator receptor cleavage followed by increased synthesis.

CONCLUSION

Blood and ascitic suPAR levels provide distinct, but relevant prognostic information on the severity of complications in patients with end-stage liver disease.

Evaluation of different therapeutic approaches for spontaneous bacterial peritonitis

BACKGROUND AND STUDY AIMS

Spontaneous bacterial peritonitis (SBP) is a significant cause of mortality in cirrhosis. Reducing toxic burden of infected ascitic fluid through paracentesis needs further studies as adjunctive therapy of SBP. We aimed to evaluate different therapies for SBP.

PATIENTS AND METHODS

Thirty-six cirrhotic ascitic patients with SBP were examined and classified according to treatment modality (5-7 days) into: Group A received cefotaxime, group B received cefotaxime and albumin 1.5 g/kg body weight within 6h of SBP being diagnosed and 1g/kg body weight on day 3, group C received cefotaxime and paracentesis with volume dependent albumin infusion. Control group of 12 cirrhotic ascitic patients free from SBP were included. Routine laboratory tests, ascitic fluid analysis for leucocytes and culture were done, inflammatory mediators such as nitric oxide and tumour necrosis factor alpha were measured in serum and ascitic fluid. Duplex-Doppler assessment of portal flow volume and renal resistive index, Echocardiography to measure end diastolic and end systolic volumes, stroke volume and cardiac output were done. Tests were carried out before and after therapy.

RESULTS

Treatment response was assessed by, cardiac haemodynamics, portal and renal flow and NO and TNF. All studied parameters; laboratory, cardiac, Doppler exhibited a significant improvement in group B in contrast to the other groups as demonstrated by post therapy reduction of (blood and ascitic fluid WBCs & PNLS, serum and ascitic NO & TNF and renal resistive index), elevation of (serum albumin and portal flow volume) and improvement of cardiac haemodynamic.

CONCLUSION

Treatment of spontaneous bacterial peritonitis by cefotaxime and body weight based albumin infusion gave most favourable results compared to other regimens. Postulation of removing toxic burden through paracentesis has not been confirmed.

Soluble CD163, a marker of Kupffer cell activation, is related to portal hypertension in patients with liver cirrhosis

BACKGROUND

Activation of Kupffer cells may be involved in the pathogenesis of portal hypertension by release of vasoconstrictive substances and fibrosis due to co-activation of hepatic stellate cells.

AIM

To study soluble plasma (s) CD163, a specific marker of activated macrophages, as a biomarker for portal hypertension in patients with liver cirrhosis.

METHODS

We measured sCD163 concentration and the hepatic venous pressure gradient (HVPG) by liver vein catheterisation in 81 cirrhosis patients (Child-Pugh CP-A: n = 26, CP-B: n = 29, CP-C: n = 26) and 22 healthy subjects. We also measured their cardiac output (CO), cardiac index and systemic vascular resistance (SVR). Liver status was examined by Child-Pugh and MELD-score.

RESULTS

In cirrhosis, sCD163 concentration was nearly three times higher than in controls (4.7 ± 2.5 vs. 1.6 ± 0.5 mg/L, P < 0.001). sCD163 was also higher, as measured in steps by CP-score (P < 0.001). The HVPG rose steeply to an asymptote of 22 mmHg with sCD163 up to about 5 mg/L and not to higher values with higher sCD163. In a multivariate analysis, sCD163 was the only independent predictor of the HVPG but did not predict any of the systemic circulatory findings. sCD163 > 3.95 mg/L (upper normal limit) predicted HVPG ≥ 10 mmHg with a positive predictive value of 0.99.

CONCLUSIONS

Circulating sCD163 originating from activated Kupffer cells is increased in cirrhosis with increasing Child-Pugh score and with increasing HVPG, and it is an independent predictor for HVPG. These findings support a primary role of macrophage activation in portal hypertension, and may indicate a target for biological intervention.

Hepatic encephalopathy

Hepatic encephalopathy (HE) represents a continuum of transient and reversible neurologic and psychiatric dysfunction. It is a reversible state of impaired cognitive function or altered consciousness in patients with liver disease or portosystemic shunting. Over the last several years, high-quality studies have been conducted on various pharmacologic therapies for HE; as more data emerge, it is hoped that HE will become a more easily treated complication of decompensated liver disease. In the interim, it is important that physicians continue to screen for minimal HE and treat patients early in addition to continuing to provide current treatments of overt HE.

Low serum concentration of apolipoprotein A-I is an indicator of poor prognosis in cirrhotic patients with severe sepsis

BACKGROUND/AIMS

Severe sepsis is frequently associated with hypocholesterolemia which is also a common finding in cirrhotic patients. Lipoprotein is capable of binding endotoxin to which cirrhotic patients exhibit an excessive pro-inflammatory response.

METHODS

We evaluated the relationship between lipid levels, inflammatory cytokines and clinical outcomes in 103 cirrhotic patients with severe sepsis.

RESULTS

The non-survivors had significantly lower concentrations of total cholesterol, high-density lipoprotein (HDL), and apolipoprotein A-I (APO A-I). HDL and APO A-I levels were inversely correlated with interleukin-6, tumor necrosis factor-alpha, and various disease severity scores. Serum creatinine, mean arterial pressure and low level of APO A-I (<47.5mg/dl) were independent factors to predict 90-day mortality. The cumulative survival rates at 90 days were 63.8% and 8.9% for the high APO A-I and low APO A-I groups (p<0.0001). Low APO A-I was also associated with lower mean arterial pressure, higher rate of vasopressor dependency, and greater plasma renin activity.

CONCLUSIONS

Serum levels of HDL and APO A-I are inversely correlated with liver reserve and disease severity in cirrhotic patients with severe sepsis. Low level of APO A-I is associated with a marked impairment of effective arterial volume, multiple organ dysfunction and a poor prognosis.

Ethyl pyruvate prevents intestinal inflammatory response and oxidative stress in a rat model of extrahepatic cholestasis

BACKGROUND

Ringer's ethyl pyruvate solution (REPS) has been shown to ameliorate liver injury in a murine model of extrahepatic cholestasis. The goal of the present investigation was to gain additional information about whether infusing REPS instead of Ringer's lactate solution (RLS) after inducing obstructive jaundice would be beneficial to intestinal barrier function, inflammatory response, and oxidative stress.

METHODS

Male Sprague Dawley rats were divided into three groups: Group Sham (n=6), sham-treated controls; Group RLS (n=9), common bile duct ligation (CBDL) plus RLS; and Group REPS (n=9), CBDL plus REPS. On 14 d after BDL, the rats were sacrificed and intestinal permeability was analyzed. Ileal IL-6 and TNF-alpha levels, malondialdehyde (MDA), glutathione (GSH), myeloperoxidase (MPO), and NF-kappaB activity were determined. Histologic examination and apoptosis of ileum were also examined.

RESULTS

Relative to sham-treated controls, CBDL in RLS-treated rats were associated with increased intestinal permeability to FITC-labeled dextran (4.51+/-0.85 versus 0.44+/-0.18, P<0.01), histopathologic damage and apoptosis (68.4+/-13.4 versus 6.7+/-1.9 pre-1000 villi cells, P<0.01). IL-6 and TNF-alpha level, MDA, MPO, and NF-kappaB activity in ileal tissues were also promoted, along with decreased GSH levels. Treatment with REPS significantly decreased intestinal permeability (3.37+/-0.71, P<0.01) and apoptosis (42.8+/-14.3 pre-1000 villi cells, P<0.01). Other changes were also significantly attenuated by treatment with REPS after CBDL.

CONCLUSIONS

The present study demonstrates that administration of REPS, but not RLS, maintains intestinal barrier function and reduces intestinal oxidative damage, inflammatory response, and apoptosis in cholestatic rats. This effect of ethyl pyruvate may be useful for preventing intestinal injury in patients with biliary obstruction.

Regulation of the postburn wound inflammatory response by gammadelta T-cells

Healing of the burn injury site is a critical component of the patient's successful recovery from this form of trauma. Previous studies from our laboratory have demonstrated that gammadelta T-cells via the production of growth factors are important in burn wound healing. Nonetheless, the role of these cells in burn wound inflammation remains unknown. To study this, wild-type (WT) and gammadelta T-cell receptor-deficient (delta TCR) C57BL/6 male mice were subjected to burn injury or sham procedure. Wound cells were collected by implantation of polyvinyl alcohol sponges beneath the burn site in injured mice or beneath uninjured skin in sham mice. At 3 days after injury, infiltrating cells, wound fluid, and skin were collected for analysis. Burn injury markedly increased skin tumor necrosis factor-alpha (TNF-alpha) and monocyte chemoattractant protein 1 levels. In WT mice, the numbers of infiltrating cells were similar between nonburn wounds and burn wounds. In contrast, deltaTCRmice displayed a 6-fold reduction in the cellular infiltrate. Burn injury in WT mice caused a marked increase in burn wound TNF-alpha, monocyte chemoattractant protein 1, and interleukin 6 content as compared with nonburn wounds, whereas in delta TCRmice, the burn-induced increase of TNF-alpha and interleukin 6 was not observed. The wound cell infiltrate at 3 days postinjury was devoid of gammadelta T-cells in WT mice. It was predominately of myeloid origin expressing high levels of CD11b and F4/80. In conclusion, these findings suggest that resident gammadelta T-cells are important in the recruitment of inflammatory cells and regulation of the inflammatory response at the wound site after thermal injury.

Portal hypertension produces an evolutive hepato-intestinal pro- and anti-inflammatory response in the rat

An inflammatory etiopathogeny can be suggested in portal hypertensive enteropathy since infiltration of the intestinal wall by mononuclear cells has been described in this condition. This work was carried out with the intention of shedding light on this matter. Male Wistar rats were divided into 4 control groups and 4 groups with partial portal vein ligation at 1, 2, 3 and 15 months. TNF-alpha, IL-1beta and IL-10 were quantified in liver and ileum by ELISA. CO and NO were measured in splanchnic and systemic vein by spectrophotometry and Griess reaction, respectively. Expression of constitutive and inducible isoforms of NO and HO were assayed by Western blot in liver and ileum. An increased hepatic release of proinflammatory mediators (TNF-alpha, IL-1beta and NO) associated with intestinal release of anti-inflammatory mediators (IL-10, CO) occurs in an early evolutive phase (1 month) of experimental portal hypertension. On the contrary, in the long-term (15 months), the increase in the intestinal release of proinflammatory mediators (TNF-alpha, IL-1beta) is associated with an increase in the hepatic release of anti-inflammatory mediators (IL-10, CO). These results suggest that experimental prehepatic portal hypertension presents changes in the serum and tissular (liver and small bowel) concentrations of mediators which are considered as pro- and anti-inflammatory.

Heme oxygenase attenuates oxidative stress and inflammation, and increases VEGF expression in portal hypertensive rats

BACKGROUND/AIMS

The pathophysiological significance of heme oxygenase-1 up-regulation in portal hypertension is not completely understood. In this study, we determined the role of heme oxygenase-1 on oxidative stress, inflammation, angiogenesis, and splanchnic hemodynamics in rats with portal hypertension induced by partial portal vein ligation.

METHODS

Rats were treated with the heme oxygenase inhibitor SnMP or vehicle for 7 days. Then, oxidative stress was quantified by superoxide anion production, and inflammatory response was assessed by immunofluorescence. Expression of angiogenesis mediators was determined by western blotting, and the extent of portosystemic collaterals by radioactive microspheres. Hemodynamic studies were performed by flowmetry.

RESULTS

Oxidative stress was significantly increased in the mesentery of portal hypertensive rats, as compared with sham-operated controls. In portal hypertensive rats, chronic heme oxygenase inhibition (1) potentiated oxidative stress and inflammation, (2) significantly decreased VEGF expression, without modifying the extent of collaterals or the splanchnic neovascularization, and (3) significantly decreased superior mesenteric artery blood flow and portal pressure.

CONCLUSIONS

This study demonstrates that heme oxygenase plays an important (beneficial) role attenuating oxidative stress and inflammation, but it also plays a detrimental role in stimulating VEGF production, and contributing to the development of hyperdynamic splanchnic circulation in rats with portal hypertension.

High-density lipoproteins reduce the effect of endotoxin on cytokine production and systemic hemodynamics in cirrhotic rats with ascites

BACKGROUND/AIMS

Hypersensitivity to endotoxin is a recognized feature in cirrhosis. High-density lipoproteins (HDL) have a high capacity to inactivate endotoxin. The aim was to determine if HDL reduces the effect of endotoxin on cytokine production and systemic hemodynamics in experimental cirrhosis.

METHODS

The study was performed in control and rats with carbon-tetrachloride induced cirrhosis with ascites. Hemodynamic parameters were determined before and after several doses of endotoxin. The effects of 25 microg/kg of endotoxin on the serum concentration of TNFalpha and mean arterial pressure (MAP) were determined after treatment with HDL (80 mg/kg) or saline.

RESULTS

Whereas endotoxin decreased MAP only at doses of 100 and 1000 microg/kg in control rats, in cirrhotic rats significant hypotension occurred at doses of 25, 50, 100 and 1000 microg/kg. Following the administration of endotoxin (25 microg/kg) the serum levels of TNFalpha were 140 times higher in cirrhotic than in control rats (89?835+/-21?090 vs. 625+/-137 pg/ml; P<0.001). Serum TNFalpha was 80% lower in cirrhotic rats pretreated with HDL (18?890+/-5012 pg/ml; P<0.001) than in those pretreated with saline. The administration of endotoxin (25 microg/kg) was associated with a significant lower decrease of MAP in cirrhotic rats pretreated with HDL than in those receiving saline (11.9+/-3.5 vs. 24.7+/-4.3%; P<0.05).

CONCLUSIONS

HDL attenuates the increased effect of endotoxin on cytokine production and systemic hemodynamic in cirrhosis.

Effect of endotoxin on portal hemodynamic in rats

AIM: To study the effects of endotoxin on portal hemodynamic of normal and noncirrhotic portal hypertensive rats.

METHODS: Normal rats were intraperitonealy injected with 0.1, 0.25, 0.5, 1.0, 2.0, 4.0 mg·kg^-1 of lipopolysaccharide (LPS) respectively, portal vein ligation (PVL) and intrahepatic portal occlusion (IPO) rats as well as sham-operated rats were treated with an intraperitoneal injection of 1.0 mg·kg^-1 of LPS, the portal vein pressure (PVP), portal venous flow (PVF), inferior vena cava pressure (IVCP) and portal vein resistance (PVR) were detected 4 hours after injection.

RESULTS: PVF of the 5 groups of rats accepting intraperitoneal injection of LPS were increased from 14.0 to 18.0, 22.2, 26.2, 34.8, 39.6, 38.8 mL·min^-1 4 hours after injection of LPS (P < 0.01). PVP of the 4 groups of rats accepting more than 0.1 mg/kg·b.w of LPS was increased from 1.04 to1.25, 1.50, 1.80, 1.95, 2.05 kPa (P < 0.01). The increments of PVF and PVP were in a dose-dependent manner of LPS. PVR of the 5 groups of rats was decreased from 51 to 42, 44, 48, 45, 44, 47 kPa·min·L^-1 (P < 0.05) and no dose-dependent manner was observed. PVF of PVL, IPO and sham-operated rats increased from 22.6 to 32.8, 22.0 to 28.0, 14.0 to 34.8 mL·min^-1 (P < 0.01), and PVP increased from 1.86 to 2.24, 1.74 to 1.95, 1.04 to 1.80 kPa (P < 0.01), PVR decreased from 71 to 61, 67 to 61, 52 to 44 kPa·min·L^-1 after intraperitoneal injection of 1 mg·kg^-1 of LPS. The increments of PVF and PVP of PVL and IPO rats were significantly less than the sham-operated rats (P < 0.01), There was no significant difference between the amounts of PVR decreased in the two groups of PHT model rats and sham-operated rats (P > 0.05) after intraperitoneal injection 1 mg·kg^-1 of LPS.

CONCLUSION: Endotoxin could prompt portal hypertension of the normal and noncirrhotic portal hypertensive rats by increasing portal blood flow mainly.

Monocyte activation in alcoholic liver disease

Activated monocytes and macrophages have been postulated to play an important role in the pathogenesis of alcoholic liver disease (ALD). Monocyte activation can be documented by measurement of neopterin, adhesion cell molecules, and certain proinflammatory cytokines and chemokines. We first became interested in the role of monocytes and monocyte-derived cytokines in ALD in relation to altered zinc metabolism that occurs regularly in ALD. Patients with ALD have hypozincemia, which responds poorly to oral zinc supplementation. We have shown that in ALD monocytes make a low-molecular-weight substance that, when injected into rabbits, causes prominent hypozincemia. Subsequently, multiple cytokines [especially tumor necrosis factor (TNF) and interleukin (IL)-8] have been shown to be overproduced by monocytes in ALD. We initially showed that monocytes in ALD spontaneously produce TNF and overproduce TNF in response to a lipopolysaccharide (LPS) stimulus, and this could be attenuated by antioxidants in vitro and in vivo. Alterations in the endotoxin-binding protein LPS-binding protein, in CD14, and in the endotoxin receptor Toll-like receptor 4 all may play roles in enhanced proinflammatory cytokine signaling in ALD. Moreover, several groups have documented increased TNF receptor density in monocytes in ALD. Inadequate negative regulation of TNF occurs at multiple levels in ALD. This includes decreased monocyte production of the important antiinflammatory cytokine IL-10 and blunted response to the antiinflammatory properties of adenosine. Finally, generation of reactive oxygen species (which occurs during alcohol metabolism) and products of lipid peroxidation induce production of cytokines, such as TNF and IL-8. In conclusion, there are multiple overlapping potential mechanisms for enhanced proinflammatory cytokine production by monocytes in ALD. We postulate that activation of monocytes and macrophages with subsequent proinflammatory cytokine production plays an important role in certain metabolic complications of ALD and is a component of the liver injury of ALD.

Resistance of macrophages to the suppressive effect of interleukin-10 following thermal injury

The activation of a macrophage (Mphi)-dependent proinflammatory cascade following thermal injury plays an important role in the development of immunosuppression and increased susceptibility to subsequent sepsis in burn patients. In contrast, although interleukin (IL)-10, an anti-inflammatory cytokine that can downregulate M phi activity, has also been implicated in postburn immune dysfunction, its role in the regulation of M phi function postburn remains unclear. To study this, C57BL/6 female mice were subjected to a 25% total body surface area third-degree scald burn, and splenic Mphis were isolated 7 days later. Lipopolysaccharide (LPS)-stimulated IL-10, IL-6, tumor necrosis factor (TNF)-alpha, and nitric oxide (NO) production were significantly increased in the burn group compared with shams. Blockade of endogenous IL-10 activity enhanced IL-6 and TNF-alpha release, but not NO release, in both groups. The addition of exogenous IL-10 to the M phi cultures dose dependently suppressed production of these inflammatory mediators in both groups. The timing of IL-10 addition to the cultures in relation to LPS stimulation, however, was critical. The suppressive effect of exogenous IL-10 was attenuated in both groups when the cells were exposed to IL-10 at 4-6 h after LPS stimulation; however, Mphis from injured mice were significantly better able to maintain inflammatory mediator-productive capacity. The resistance of Mphis from injured mice to IL-10-mediated suppression correlated with decreased IL-10 receptor (IL-10R) expression and increased CD11b expression. These findings suggest that Mphis, following thermal injury, display resistance to suppression by IL-10 due in part to downregulation of IL-10R expression.

Neutrophil adhesion is impaired in the mesentery but not in the liver sinusoids of portal hypertensive rats

Altered leukocyte/cytokine response to inflammation has been observed in human and experimental portal hypertension. The aim of this study was to characterize leukocyte adhesion in portal hypertensive (PPVL) rats stimulated with endotoxin. Leukocyte rolling, adhesion, and migration assessed by intravital microscopy were impaired in mesenteric venules after lipopolysaccharide administration (150 microg/kg) in PPVL vs. sham-operated rats. Analysis of leukocyte L-selectin expression and soluble L-selectin showed that this defective adhesion was related to increased L-selectin shedding. In vitro experiments using isolated leukocytes treated with phorbol 12-myristate 13-acetate showed that monocytes and neutrophils but not lymphocytes were hyperreactive to cell activation, as measured by CD11b overexpression and increased L-selectin shedding in PPVL rats. However, neutrophil emigration in liver sinusoids and in the lung 3 h after endotoxin injection were similar in both groups of animals. Thus the alterations in leukocyte activation and adhesion molecule expression observed in this study may contribute to a better understanding of the higher susceptibility and severity of bacterial infections in cirrhotic patients with portal hypertension.

Endotoxin clearance and its relation to hepatic and renal disturbances in rats with liver cirrhosis

BACKGROUND/AIMS

Little is known about endotoxin clearance and secretion of cytokines from macrophages in liver cirrhosis. The aims of this study were to investigate the relationship of endotoxin clearance and release of tumor necrosis factor alpha by various macrophages to hepatic and renal disturbances in liver cirrhosis.

METHODS

Male Sprague-Dawley rats were given 0.04% thioacetamide orally for 6 or 12 months. The organ distribution of infused [3H]-endotoxin (10 microg/kg b.w.) was analyzed at 30 min or at 24 h. Uptake of [3H]-endotoxin and secretion of tumor necrosis factor alpha by Kupffer cells, splenic macrophages and peripheral blood monocytes (1 x 10(4) cells/ml) from cirrhotic and control rats were determined.

RESULTS

In cirrhotic rats, more endotoxin was left in the body and more endotoxin accumulated in the spleen and kidney, and thus was related to elevation of serum total bilirubin, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, creatinine and tumor necrosis factor alpha. Endotoxin uptake and tumor necrosis factor alpha release by the Kupffer cells were decreased and those by the splenic macrophages and peripheral blood monocytes were increased in cirrhotic rats.

CONCLUSIONS

In liver cirrhosis, impaired clearance of endotoxin together with increased secretion of tumor necrosis factor alpha by extrahepatic macrophages may play an important role in the progression of hepatic and renal disturbances.