Intestinal permeability in rats with CCl4-induced portal hypertension

AIM: To investigate the intestinal barrier changes in rats with CCl4-induced portal hypertension.METHODS: The permeability of intestinal barrier detected by Lanthanum as a tracer was evaluated in rats. Bacterial translocation and plasma endotoxin were also determined.RESULTS: The incidence of bacterial translocation was 85% in rats with CCl4-induced portal hypertension, which was significantly higher than that in control rats (20%,P＜0.01). Plasma endotoxin level was significantly higher in experimental group than in control group. Permeability of the epithelial mucosa and pathological alteration were increased in the ileum and the microvilli became shorter and thinner in rats with portal hypertension.CONCLUSION: Bacterial translocation occurs in rats with CCl4-induced portal hypertension and increased permeability between epithelial cells contributes to the translocation.     

Intestinal permeability in rats with CCI4-induced portal hypertension

AIM:To investigate the intestinal barrier changes in ratswith CCl_4-induced portal hypertension.METHODS:The permeability of intestinal barrier detectedby Lanthanum as a tracer was evaluated in rats,Bacterialtranslocation and plasma endotoxin were also determined.RESULTS:The incidence of bacterial translocation was85% in rats with CCl_4-induced portal hypertension,whichwas significantly higher than that in control rats(20%,P<0.01).Plasma endotoxin level was significantly higherin experimental group than in control group.Permeabilityof the epithelial mucosa and pathological alteration wereincreased in the ileum and the microvilli became shorterand thinner in rats with portal hypertension.CONCLUSION:Bacterial translocation occurs in ratswith CCl_4-induced portal hypertension and increasedpermeability between epithelial cells contributes to thetranslocation.     

Gut-liver axis signaling in portal hypertension

Portal hypertension(PHT) in advanced chronic liver disease(ACLD) results from increased intrahepatic resistance caused by pathologic changes of liver tissue composition(structural component) and intrahepatic vasoconstriction(functional component). PHT is an important driver of hepatic decompensation such as development of ascites or variceal bleeding. Dysbiosis and an impaired intestinal barrier in ACLD facilitate translocation of bacteria and pathogen-associated molecular patterns(PAMPs) that promote disease progression via immune system activation with subsequent induction of proinflammatory and profibrogenic pathways. Congestive portal venous blood flow represents a critical pathophysiological mechanism linking PHT to increased intestinal permeability: The intestinal barrier function is affected by impaired microcirculation, neoangiogenesis, and abnormal vascular and mucosal permeability. The close bidirectional relationship between the gut and the liver has been termed "gut-liver axis". Treatment strategies targeting the gut-liver axis by modulation of microbiota composition and function, intestinal barrier integrity, as well as amelioration of liver fibrosis and PHT are supposed to exert beneficial effects. The activation of the farnesoid X receptor in the liver and the gut was associated with beneficial effects in animal experiments, however,further studies regarding efficacy and safety of pharmacological FXR modulation in patients with ACLD are needed. In this review, we summarize the clinical impact of PHT on the course of liver disease, discuss the underlying pathophysiological link of PHT to gut-liver axis signaling, and provide insight into molecular mechanisms that may represent novel therapeutic targets.     

氯膦酸二钠脂质体清除肝内巨噬细胞对CCl4诱导的慢性肝损伤大鼠门脉高压的影响*

目的 观察氯膦酸二钠脂质体清除肝内巨噬细胞对CCl₄诱导的慢性肝损伤大鼠门脉高压的影响。方法 随机将48只Wistar大鼠分为对照组和模型组,每组24只。采用皮下注射橄榄油和四氯化碳(CCl₄)法制备肝损伤模型。在实验d₇₀,再将每组分为2个亚组,分别经尾静脉注射磷酸盐缓冲液脂质体(PL)或氯膦酸二钠脂质体(CL)处理。在实验d₁₀₅,使用BL-420F生理机能实验系统测定大鼠肝脏在体门静脉压力,采用ELISA法检测血sCD163水平,采用免疫组化法检测肝组织CD163和诱导型一氧化氮合酶(iNOS)蛋白表达。结果 在对照组内,CL处理大鼠血清sCD163水平为(798.6±61.9) pg/L,显著低于PL处理组[(848.3±26.2) pg/L,P＜0.05];在模型组内,CL处理大鼠肝脏指数和门静脉压力分别为(4.7±0.8)和(10.6±2.0) mmHg,显著低于PL处理组[分别为(5.6±1.3)和(12.4±2.7) mmHg,P＜0.05];模型组CL处理大鼠血清ALT、AST和sCD163水平分别为(69.9±21.4) U/L、(202.8±14.2) U/L和(980.1±122.3) pg/L,与PL处理大鼠比,均有显著性差异[分别为(97.8±39.6) U/L、(290.6±168.1) U/L和(1083.2±97.2) pg/L,P＜0.05];免疫组化结果显示,CL处理大鼠肝组织CD163和iNOS蛋白阳性表达较PL处理大鼠有不同程度的减弱。结论 巨噬细胞参与门脉高压的发生和发展。清除巨噬细胞可降低门静脉压力。     

Role of estrogen receptor &beta; selective agonist in ameliorating portal hypertension in rats with CCl4-induced liver cirrhosis

AIM: To investigate the role of diarylpropionitrile (DPN), a selective agonist of estrogen receptor β (ERβ), in liver cirrhosis with portal hypertension (PHT) and isolated hepatic stellate cells (HSCs). METHODS: Female Sprague-Dawley rats were ovariectomized (OVX), and liver cirrhosis with PHT was induced by CCl₄ injection. DPN and PHTPP, the selective ERβ agonist and antagonist, were used as drug interventions. Liver fibrosis was assessed by hematoxylin and eosin (HE) and Masson’s trichrome staining and by analyzing smooth muscle actin expression. Hemodynamic parameters were determined in vivo using colored microspheres technique. Protein expression and phosphorylation were determined by immunohistochemical staining and Western blot analysis. Messenger RNA levels were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). Collagen gel contraction assay was performed using gel lattices containing HSCs treated with DPN, PHTPP, or Y-27632 prior to ET-1 addition. RESULTS: Treatment with DPN in vivo greatly lowered portal pressure and improved hemodynamic parameters without affecting mean arterial pressure, which was associated with the attenuation of liver fibrosis and intrahepatic vascular resistance (IHVR). In CCl₄-treated rat livers, DPN significantly decreased the expression of RhoA and ROCK II, and even suppressed ROCK II activity. Moreover, DPN remarkedly increased the levels of endothelial nitric oxide synthase (eNOS) and phosphorylated eNOS, and promoted the activities of protein kinase G (PKG), which is an NO effector in the liver. Furthermore, DPN reduced the contractility of activated HSCs in the 3-dimensional stress-relaxed collagen lattices, and decreased the ROCK II activity in activated HSCs. Finally, in vivo/in vitro experiments demonstrated that MLC activity was inhibited by DPN. CONCLUSION: For OVX rats with liver cirrhosis, DPN suppressed liver RhoA/ROCK signal, facilitated NO/PKG pathways, and decreased IHVR, giving rise to reduced portal pressure. Therefore, DPN represents a relevant treatment choice against PHT in cirrhotic patients, especially postmenopausal women.     

Effect of increased hepatic platelet activating factor and its receptor portal hypertension in CCl4-induced liver cirrhosis

AIM: To evaluate the changes in hepatic platelet activating factor (PAF) and its receptors and their effect on portal pressure of cirrhotic rats induced by CCl4. METHODS: A model of liver cirrhosis was replicated in rats by intra-peritoneal injection of CCl4 for 8 wk. We determined the effect of hepatic PAF and its receptor level on portal and arterial pressure by EIA, saturation binding and RT-PCR technique. RESULTS: Compared to control rats, cirrhotic rats had higher hepatic PAF levels and output as well as higher plasma PAF levels (P<0.01, P<0.01, P<0.05, respectively). Both hepatic PAF receptor mRNA levels and PAF binding were nearly 3-fold greater in cirrhotic rats (P<0.01). Portal injection of PAF (1 g/kg WT) increased the portal pressure by 22% and 33% in control and cirrhotic rats, respectively. In contrast, the arterial pressure was decreased in the both groups (54% in control rats and 42% in cirrhotic rats). Injection of the PAF antagonist BN52021 (5 mg/kg WT) decreased the portal pressure by 16% in cirrhotic rats but had no effect in the control rats. CONCLUSION: The upregulation of the PAF system contributes to hepatic hemodynamic and metabolic abnormalities in cirrhosis, and the increased release of PAF into the circulation has impacts on the systemic hemodynamics.     

Altered blood-brain barrier permeability in rats with prehepatic portal hypertension turns to normal when portal pressure is lowered

AIM: To study the blood-brain barrier integrity in prehe-patic portal hypertensive rats induced by partial portal vein ligation, at 14 and 40 d after ligation when portal pressure is spontaneously normalized. METHODS: Adult male Wistar rats were divided into four groups: GroupⅠ: Sham14d, sham operated; GroupⅡ: PH14d, portal vein stenosis; (both groups were used 14 days after surgery); GroupⅢ: Sham40d, Sham operated and GroupⅣ: PH40d Portal vein stenosis (GroupsⅡandⅣused 40 d after surgery). Plasma ammonia, plasma and cerebrospinal fluid protein and liver enzymes concentrations were determined. Trypan and Evans blue dyes, systemically injected, were investigated in hippocampus to study blood-brain barrier integrity. Portal pressure was periodically recorded. RESULTS: Forty days after stricture, portal pressure was normalized, plasma ammonia was moderately high, and both dyes were absent in central nervous system parenchyma. All other parameters were reestablished. When portal pressure was normalized and ammonia level was lowered, but not normal, the altered integrity of blood-brain barrier becomes reestablished. CONCLUSION: The impairment of blood-brain barrier and subsequent normalization could be a mechanism involved in hepatic encephalopathy reversibility, Hemo-dynamic changes and ammonia could trigger blood-brain barrier alterations and its reestablishment.     

Altered blood-brain barrier permeability in rats with prehepatic portal hypertension turns to normal when portal pressure is lowered

AIM: To study the blood-brain barrier integrity in prehepatic portal hypertensive rats induced by partial portal vein ligation, at 14 and 40 d after ligation when portal pressure is spontaneously normalized.METHODS: Adult male Wistar rats were divided into four groups: Group I: Sham_14d , sham operated; Group II: PH_14d , portal vein stenosis; (both groups were used 14 days after surgery); Group III: Sham_40d, Sham operated and Group IV: PH_40d Portal vein stenosis (Groups II and IV used 40 d after surgery). Plasma ammonia, plasma and cerebrospinal fluid protein and liver enzymes concentrations were determined. Trypan and Evans blue dyes, systemically injected, were investigated in hippocampus to study blood-brain barrier integrity. Portal pressure was periodically recorded.RESULTS: Forty days after stricture, portal pressure was normalized, plasma ammonia was moderately high, and both dyes were absent in central nervous system parenchyma. All other parameters were reestablished. When portal pressure was normalized and ammonia level was lowered, but not normal, the altered integrity of blood-brain barrier becomes reestablished.CONCLUSION: The impairment of blood-brain barrier and subsequent normalization could be a mechanism involved in hepatic encephalopathy reversibility. Hemodynamic changes and ammonia could trigger blood-brain barrier alterations and its reestablishment.     

Glutamine and recombinant human growth hormone protect intestinal barrier function following portal hypertension surgery

AIM： To evaluate the effects of combined treatment of glutamine （Gln） and recombinant human growth hormone（rhGH） on intestinal barrier function following portal hypertension surgery.
METHODS： This study was designed as a prospective, randomized and controlled clinical trial. Forty two patients after portal hypertension surgery were randomly assigned into 2 groups： control group （n = 20） and supplemental group （adding Gin and rhGH, n = 22）. Every patient received isocaloric and isonitrogenous standard total parenteral nutrition （TPN） starting 3 d after surgery for 7 d. Blood samples were obtained before surgery and at the 3rd and 10th day postoperatively. Host immunity was evaluated by measuring levels of CD4, CD8, CD4/CD8, IgG, IgM and IgA, and the inflammatory responses were determined by assessing IL-2, TNF-α and C-reactive protein （CRP） levels. Intestinal permeability and integrity was evaluated by L/M test and histological examination, respectively.
RESULTS： On postoperative d 10, CD4, CD4/CD8, IgG and IL-2 levels in supplemental group were significantly higher than those in control group （33.7±5.5 vs 31.0 ± 5.4, P 〈 0.05, （1.17±0.32 vs 1.05 ± 0.15, P 〈 0.05, 13.94±1.09 vs 12.33±1.33, P 〈 0.05, and 368.12 ± 59.25 vs 318.12 ± 45.65, P 〈 0.05, respectively）, whereas the increase in serum TNF-α concentration was significantly reduced （41.02 ± 27.56 vs 160.09 ± 35.17, P 〈 0.05）. The increase in L/M ratio was significantly lower in the supplemental group than in the control group （0.0166 ± 0.0017 vs 0.0339 ± 0.0028, P 〈 0.05）. Moreover, mucosal integrity in the supplemental group was better than in the control group.
CONCLUSION： Postoperative administration of TPN supplemented with Gin and rhGH in patients after portal hypertension surgery improves immune function, modulates inflammatory response, prevents the intestinal mucous membrane from atrophy and preserves intestinal integrity.     

汉防己甲素对肝硬化大鼠胃黏膜微循环及超微结构的影响

目的:观察汉防己甲素降低大鼠肝硬化门脉高压(PHT)的疗效和对胃黏膜微循环及其超微结构的影响.方法:制作肝硬化PHT模型,成模后分为模型(M)组、汉防己甲素(T)组、普萘洛尔组(P)及正常对照(N)组,治疗15 d后进行各指标的测定.结果:与M组比较,T组门静脉压力(PVP)明显降低(P<0.01),ALT,HA及PCⅢ指标下降(P<0.05),平均动脉压(MAP)和心率(HR)无明显变化;P组引起了PVP明显降低(P<0.01)和HR的减慢(P<0.05),MAP,ALT,HA及PCⅢ无明显变化;T组、P组光镜下胃黏膜毛细血管最大直径及面积明显减小(P<0.01),透射电镜下胃黏膜超微结构的损伤明显减轻.结论:汉防己甲素能有效、安全地降低大鼠肝硬化门脉压力,可有效改善其胃黏膜微循环及超微的变化,为临床治疗门脉高压性胃病提供实验依据.     

门静脉高压大鼠内源性硫化氢体系的变化

在肝硬化门静脉高压形成中，门静脉系统的血流量增加是门静脉高压产生和加重的重要因素之一，近几年来人们发现气体信号分子NO、CO可以引起内脏血管扩张而使门静脉系统血流量增加。最近的研究发现H2S具有与NO、CO相似的生物学效应，如舒张血管、抑制平滑肌细胞增殖等。内源性H2S在诸多心血管疾病的发病过程中发挥着重要的病理生理学作用，广泛参与低氧性肺动脉高压、肺动脉高压、高血压、感染性休克等心肺疾病的发病过程。在门静脉高压的发病过程中是否也有H2S的参与，目前国内外鲜见报道。本研究以部分门静脉结扎大鼠为对象，观察门静脉高压大鼠门静脉压力的变化以及CSE基因表达的改变，以探讨H2S在门静脉高压中的作用。     

Intestinal barrier dysfunction in cirrhosis: Current concepts in pathophysiology and clinical implications

The intestinal lumen is a host place for a wide range of microbiota and sets a unique interplay between local immune system, inflammatory cells and intestinal epithelium, forming a physical barrier against microbial invaders and toxins. Bacterial translocation is the migration of viable or nonviable microorganisms or their pathogen-associated molecular patterns, such as lipopolysaccharide, from the gut lumen to the mesenteric lymph nodes, systemic circulation and other normally sterile extraintestinal sites. A series of studies have shown that translocation of bacteria and their products across the intestinal barrier is a commonplace in patients with liver disease. The deterioration of intestinal barrier integrity and the consulting increased intestinal permeability in cirrhotic patients play a pivotal pathophysiological role in the development of severe complications as high rate of infections, spontaneous bacterial peritonitis, hepatic encephalopathy, hepatorenal syndrome, variceal bleeding, progression of liver injury and hepatocellular carcinoma. Nevertheless, the exact cellular and molecular mechanisms implicated in the phenomenon of microbial translocation in liver cirrhosis have not been fully elucidated yet.     

Intestinal bacterial overgrowth and bacterial translocation in cirrhotic rats with ascites

Background/Aims: Translocation of indigenous bacterial from the gut lumen of cirrhotic animals to mesenteric lymph nodes appears to be an important step in the pathogenesis of spontaneous bacterial peritonitis. However, the sequence of events leading to translocation remains unclear. One of the most predictable risk factors for translocation is overgrowth of gut bacterial flora. The present study was designed to compare the intestinal aerobic bacterial flora of cecal stools at the time of sacrifice between cirrhotic and normal rats and to evaluate the role of intestinal aerobic bacterial overgrowth in bacterial translocation in cirrhotic rats.Methods: Thirty-five male Sprague-Dawley rats with carbon tetrachloride-induced cirrhosis and ascites and 10 normal rats were included in this study. Cirrhotic rats were sacrificed when ill and samples of ascitic fluid, mesenteric lymph nodes and cecal stool were taken for detecting quantitatively aerobic bacteria.Results: Total intestinal aerobic bacterial count in cecal stool at the time of sacrifice was significantly increased in cirrhotic rats with bacterial translocation with or without spontaneous bacterial peritonitis compared to cirrhotic rats without bacterial translocation (p<0.001 and p<0.001, respectively) and to normal rats (p<0.001 and p<0.001, respectively). Of the 42 species of bacteria translocating to the mesenteric lymph nodes, 41 (97.6%) were found in supranormal numbers in the stool at the time of sacrifice.Conclusions: Carbon tetrachloride-induced cirrhotic rats with bacterial translocation have increased total intestinal aerobic bacteria count, and intestinal bacterial overgrowth appears to play an important role in bacterial translocation in this experimental model of cirrhosis in rats.     

肝硬化门静脉高压对D-木糖吸收率的影响及意义

目的:评价D-木糖吸收率在肝硬化门静脉高压进程中的变化规律,欲探索一种非损伤性且简便实用的推测门静脉压力的方法.方法:SD大鼠80只,♂,体质量180-220 g,随机分为:正常组5只,正常饮水,正常饮食.肝硬化门脉高压诱导组75只,共成模55只,前5wk使用0.03%硫代乙酰胺,后5 wk使用0.04%硫代乙酰胺作为其饮水,停药后6wk仍继续观察肝组织及门静脉压力变化.正常组及第2、4、6、8、10、11、12、13、14、15、16周共12组,对每组大鼠检测D-木糖含量及门静脉压力,并计D-木糖吸收率与相应的门静脉压力的相关性.结果:在肝硬化进程中自第8周纤维间隔明显增生,肝小叶结构紊乱,部分可见假小叶,同时门静脉压力及D-木糖吸收率也是自第8周开始同步出现显著性差异.D-木糖吸收率与门静脉压力呈负相关,具有统计学意义(r=-0.697,P<0.01),同时得出两者的直线关系方程:y=-0.01x+0.2791.结论:D-木糖吸收率可以反映肝硬化门静脉压力的变化趋势,对于临床上判断门静脉压力的大小、评价治疗效果具有重要意义.     

Effects of propranolol on venous compliance in conscious rats with pre-hepatic portal hypertension

BACKGROUND/AIMS: The venous system is the primary capacitance region in the body. However, the influence of active changes in the venous system on the hemodynamic alterations of portal hypertension is poorly understood. To investigate venous compliance (VC) in conscious partial portal vein ligated rats (PPVL) and the effect of propranolol on VC. METHODS: Venous compliance was derived from the relationship between changes in mean circulatory filling pressure (MCFP) and changes in blood volume (BV). Measurements were performed before and after i.v. propranolol (7.5 mg/Kg) or placebo in rats with portal hypertension due to PPVL and sham operated controls. RESULTS: PPVL rats had an increased VC when compared to Sham (4.9+/-1.4 vs. 3.7+/-0.9 ml kg-1 mm Hg-1; P<0.02). VC did not change after placebo but was significantly reduced by Propranolol in PPVL (-32.9+/-15.7%; P<0,007). Propranolol did not modify venous compliance in sham operated rats (+10.9+/-13.4%; P=ns). CONCLUSIONS: Venous compliance is increased in portal hypertensive rats, suggesting that the venous system contributes to the profound circulatory changes encountered in portal hypertension. The increased venous compliance is markedly attenuated by propranolol, suggesting that this abnormality is related to increased adrenergic activity.     

门静脉高压症脾切除术后患者血浆内皮素变化与门静脉血栓形成的关系

为探讨门静脉高压症患者脾切除术后血浆内皮素 (ET)水平变化及其临床意义 ,采用放免法测定了30例肝硬变门静脉高压症行脾切除术患者 (观察组 )术前及术后 1周血浆 ET水平 ,并设对照组比较。结果显示 ,观察组术前血浆 ET水平 (6 7.2 4± 2 4 .6 3pg/ml)明显高于对照组 (33.2 1± 11.0 5 pg/ml) ,P<0 .0 0 1;术后 1周明显下降 (37.2 4± 14 .4 7pg/ml) ,P<0 .0 0 1,与对照组 (32 .4 8± 10 .6 2 pg/m l)比较无显著差异 ,P>0 .0 5。脾切除术后门静脉血栓形成者 ET水平 (5 7.90± 2 1.70 pg/m l)明显高于非血栓形成者 (33.15± 8.2 9pg/ml) ,P<0 .0 0 1。认为ET在肝硬变、门静脉高压症发生中起重要作用 ,ET增高与门静脉血栓形成有关。脾切除术后血浆 ET明显下降 ,对改善肝脏功能、降低门静脉压力具有重要意义     

Attenuation of portal hypertension by natural taurine in rats with liver cirrhosis

AIM： To investigate the inhibitory effect of natural taurine （NTau） on portal hypertension （PHT） in rats with experimentally-induced liver cirrhosis （LC）. METHODS： Experimentally-induced LC Wistar rats （20 rats/group） were treated with either oral saline or oral NTau for 6 consecutive weeks. Evaluation parameters included portal venous pressure （PVP）, portal venous resistance （PVR）, portal venous flow （PVF）, splanchnic vascular resistance （SVR） and mean arterial pressure （NAP）. Vasoactive substance levels including nitric oxide （NO）, nitric oxide synthase （NOS） and cyclic guanosine monophosphate （cGMP） were also measured. Histological investigation of type Ⅰ and Ⅲ collagen （COL Ⅰ and Ⅲ） and transforming growth factor-β1 （TGF-β1） was also performed. RESULTS： Treatment with NTau （1） significantly decreased PVP, PVR and PVF, and increased MAP and SVP; （2） markedly increased the vascular compliance and reduced the zero-stress of the portal vein; （3） markedly decreased the amount of NO and cGMP and activity of NOS; and （4） improved the pathological status of the liver tissue and reduced the expression of COL Ⅰ, COL Ⅲ and TGF-β1. CONCLUSION： NTau inhibited the LC-induced PHT by improving hyperdynamic circulation, morphology of liver and biomechanical properties of the portal vein in experimentally-induced LC rats.     

肝硬化门脉高压症患者的十二指肠损害

目的探讨肝硬化门脉高压症患者十二指肠损害的发生率及其与肝硬化病程、门脉高压性胃病、肝功能分级的关系。方法对72例肝硬化门脉高压症患者进行胃镜检查,观察十二指肠粘膜病变,同时检测14C呼气试验。另选72例接受胃镜检查的非肝硬化门脉高压患者为对照组。结果肝硬化门脉高压症患者十二指肠糜烂发生率为41.7%,随肝硬化病程延长和肝功能分级差而增高,而幽门螺杆菌感染率与对照组无显著性相差(P>0.05)。糜烂主要发生于十二指肠降部,糜烂轻重程度与肝功能分级无关(P>0.05)。结论肝硬化门脉高压症患者十二指肠糜烂与非特异性十二指肠炎不同,是门脉高压导致十二指肠的一种病变。