Cholangiocyte endothelin 1 and transforming growth factor beta1 production in rat experimental hepatopulmonary syndrome

BACKGROUND & AIMS: Hepatic production and release of endothelin 1 plays a central role in experimental hepatopulmonary syndrome after common bile duct ligation by stimulating pulmonary endothelial nitric oxide production. In thioacetamide-induced nonbiliary cirrhosis, hepatic endothelin 1 production and release do not occur, and hepatopulmonary syndrome does not develop. However, the source and regulation of hepatic endothelin 1 after common bile duct ligation are not fully characterized. We evaluated the sources of hepatic endothelin 1 production after common bile duct ligation in relation to thioacetamide cirrhosis and assessed whether transforming growth factor beta1 regulates endothelin 1 production. METHODS: Hepatopulmonary syndrome and hepatic and plasma endothelin 1 levels were evaluated after common bile duct ligation or thioacetamide administration. Cellular sources of endothelin 1 were assessed by immunohistochemistry and laser capture microdissection of cholangiocytes. Transforming growth factor beta1 expression and signaling were assessed by using immunohistochemistry and Western blotting and by evaluating normal rat cholangiocytes. RESULTS: Hepatic and plasma endothelin 1 levels increased and hepatopulmonary syndrome developed only after common bile duct ligation. Hepatic endothelin 1 and transforming growth factor beta1 levels increased over a similar time frame, and cholangiocytes were a major source of each peptide. Transforming growth factor beta1 signaling in cholangiocytes in vivo was evident by increased phosphorylation and nuclear localization of Smad2, and hepatic endothelin 1 levels correlated directly with liver transforming growth factor beta1 and phosphorylated Smad2 levels. Transforming growth factor beta1 also stimulated endothelin 1 promoter activity, expression, and production in normal rat cholangiocytes. CONCLUSIONS: Cholangiocytes are a major source of hepatic endothelin 1 production during the development of hepatopulmonary syndrome after common bile duct ligation, but not in thioacetamide-induced cirrhosis. Transforming growth factor beta1 stimulates cholangiocyte endothelin 1 expression and production. Cholangiocyte-derived endothelin 1 may be an important endocrine mediator of experimental hepatopulmonary syndrome.     

The association of lipopolysaccharide and inflammatory factors with hepatopulmonary syndrome and their changes after orthotopic liver transplantation

Background

The level of lipopolysaccharides (LPS) and inflammatory factors were higher in end stage liver disease patient than in normal person for the damage of intestinal mucosal barrier function. Hepatopulmonary syndrome (HPS) was a common pulmonary complication in end stage liver disease. But the association of LPS and inflammatory factors such as toll like receptor 2 (TLR2), TNF-α and ET-1 with the development of HPS was undefined.

Methods

Thirty-one HPS patients were researched (26 patients were performed liver transplantation, five were not). Ten healthy volunteers were recruited as negative control. Blood was collected from the 26 HPS patients before and 3, 7, 14, 21 and 28 days after orthotopic liver transplantation (OLT), and from five HPS patients without OLT and ten healthy volunteers once to detect TLR2 mRNA and iNOS mRNA in peripheral blood monocytes and plasma LPS, TNF-α and ET-1 level. Their levels before and after OLT were compared.

Results

TLR2 mRNA, iNOS mRNA, LPS, TNF-α and ET-1 before OLT in HPS patients were 336,594.1±366,901.1, 63,982.2±74,127.5 copies/ugRNA, 4.3±3.3, 90.1±76.0 and 319.9±124.4 ng/L, respectively. They were 10,338.3±3,814.6, 19,168.5±2,417.4 copies/ugRNA, 0.94±0.69, 2.7±0.1 and 84.2±10.6 ng/L in normal control group. They were significantly higher in HPS patients than those in control group (P<0.05). After OLT, liver function improved to normal. Also TLR2 mRNA, TNF-α and ET-1 decreased in HPS patients after OLT compared with those before OLT. And PaO₂ and PaO₂/FiO₂ improved greatly with intrapulmonary shunt decreased to normal after OLT.

Conclusions

Lipopolysaccharides at the end stage of liver disease with the release of series of inflammatory factors may be associated with the development of HPS.     

噬血细胞综合征发病机制及实验室诊断的研究进展

噬血细胞综合征（hemophagocyticsyndromes,HPS）是由于机体免疫系统功能紊乱,导致NK细胞和淋巴细胞的异常活化、大量细胞因子的释放,引起了组织细胞等吞噬细胞功能过度旺盛,从而出现吞噬大量正常造血细胞的现象。HPS病情凶险,发展迅速,临床及实验室检查表现多样,该文就近年来国内外对该病的病因、机制、临床表现、实验室诊断等研究进展做一综述。     

Analysis of pulmonary heme oxygenase-1 and nitric oxide synthase alterations in experimental hepatopulmonary syndrome

BACKGROUND & AIMS: Cirrhosis and portal hypertension due to chronic common bile duct ligation reproduce the features of human hepatopulmonary syndrome, whereas portal hypertension alone due to partial portal vein ligation does not. Nitric oxide contributes to experimental hepatopulmonary syndrome, but the nitric oxide synthase forms involved remain controversial. Recently, increased pulmonary heme oxygenase-1 expression and carbon monoxide production have also been found after common bile duct ligation. Our aim was to explore the role of the heme oxygenase-1/carbon monoxide pathway in the pathogenesis of experimental hepatopulmonary syndrome. METHODS: Pulmonary heme oxygenase-1 expression and distribution were assessed in sham; 3-week partial portal vein ligation; and 1-, 2-, 3-, 4-, and 5-week common bile duct ligation animals by Northern, Western and immunohistochemical analysis relative to endothelial and inducible nitric oxide synthase levels and to hepatopulmonary syndrome development. In vivo heme oxygenase enzyme inhibition with tin protoporphyrin IX in common bile duct ligation animals was used to define effects on intrapulmonary vasodilatation and arterial blood gases. RESULTS: Heme oxygenase-1 expression in pulmonary intravascular monocytes/macrophages and arterial carboxyhemoglobin levels increased progressively from 3 to 5 weeks after common bile duct ligation relative to controls (5-week protein levels were 15.94 +/- 1.75-fold those of sham animals; P < 0.001). Inducible nitric oxide synthase increased transiently in pulmonary intravascular monocytes/macrophages in 3-week common bile duct ligation animals, whereas pulmonary microvascular endothelial nitric oxide synthase increases began at 2 weeks and correlated with the onset of hepatopulmonary syndrome. Tin protoporphyrin treatment normalized carboxyhemoglobin and improved arterial blood gases and intrapulmonary vasodilatation, reflecting partial reversal of hepatopulmonary syndrome. CONCLUSIONS: The heme oxygenase-1/carbon monoxide system is an important contributor to the progression of experimental hepatopulmonary syndrome in addition to alterations in the endothelial nitric oxide synthase/nitric oxide pathway.     

血浆置换联合化疗对噬血细胞综合征疗效观察

目的:评价血浆置换联合化疗与单纯化疗对噬血细胞综合征的临床疗效。方法:采用回顾性研究,选取2008-02～2010-03在我院确诊并治疗的21例噬血细胞综合征患者为研究对象,采用单纯化疗(对照组)12例,血浆置换联合化疗(实验组)12例,观察其临床疗效及副作用。结果:对照组5例为临床有效,1例获临床缓解,3例疾病活动,3例为疾病再活动,有效率为50%;实验组7例为临床有效,3例获临床缓解,1例为疾病活动,1例为疾病再活动,有效率为83.3%;两组比较,差异有统计学意义(P<0.05)。结论:血浆置换联合HLH化疗对噬血细胞综合征治疗疗效确切。     

Evaluation of the protective effects of quercetin in the hepatopulmonary syndrome.

The hepatopulmonary syndrome (HPS) occurs when intrapulmonary dilatation causes hypoxemia in cirrhosis. The free radicals may play a significant contributory role in the progression of HPS, and flavonoid agents could protect against deleterious effects of free radicals. The flavonoid quercetin was evaluated in an experimental model of biliary cirrhosis induced by bile duct ligation (BDL) in rats. Quercetin was administered at 50mg/kg for 14 days to cirrhotic and non-cirrhotic rats. Bone marrow was extracted from animals to analyze micronuclei. Lung, liver and blood were extracted to detect DNA damage using the comet assay. The results showed that the micronuclei and DNA damages to lung and liver were increased in BDL rats. Quercetin caused no damage to the DNA while decreasing the occurrence of micronucleated cells in bone marrow as well as DNA damage to lung and liver in cirrhotic rats. Quercetin showed antimutagenic activity against hydroperoxides as evaluated by the oxidative stress sensitive bacterial strains TA102 Salmonella typhimurium and IC203 Escherichia coli, suggesting protection by free radical scavenging. In Saccharomyces cerevisie yeast strains lacking mitochondrial or cytosolic superoxide dismutase, these results indicate that quercetin protects cells by induction of antioxidant enzymes. The present study is the first report of genotoxic/antigenotoxic effects of quercetin in a model of animal cirrhosis. In this model, quercetin was not able to induce genotoxicity and, conversely, it increased the genomic stability in the cirrhotic rats, suggesting beneficial effects, probably by its antioxidant properties.     

模拟ICU运行的核心要素探讨

医学教育在过去10年来增加了对模拟技术的依赖,模拟技术为医学教学提供了安全实践的机会。在模拟中心建设中,模拟重症监护病房是投入最多、设备最先进的单元。重症监护病房的建设、培训和发展也越来越引起重视。为此借鉴了一些现代欧美模拟教育模式和思想,希望为模拟重症监护病房的建设和运行提供一点参考。