Splenectomy ameliorates portal pressure and anemia in animal models of cirrhotic and non-cirrhotic portal hypertension

PurposePortal hypertension (PH)-associated splenomegaly is caused by portal venous congestion and splanchnic hyperemia. This can trigger hypersplenism, which favors the development of cytopenia. We investigated the time-dependent impact of splenectomy on portal pressure and blood cell counts in animal models of non-cirrhotic and cirrhotic PH.Materials and methodsNinety-six rats underwent either partial portal vein ligation (PPVL), bile duct ligation (BDL), or sham operation (SO), with subgroups undergoing additional splenectomy. Portal pressure, mean arterial pressure, heart rate, blood cell counts and hemoglobin concentrations were evaluated throughout 5 weeks following surgery.ResultsFollowing PPVL or BDL surgery, the animals presented a progressive rise in portal pressure, paralleled by decreased mean arterial pressure and accelerated heart rate. Splenectomy curbed the development of PH in both models (PPVL: 16.25 vs. 17.93 ?mmHg, p ?= ?0.083; BDL: 13.55 vs. 15.23 ?mmHg, p ?= ?0.028), increased mean arterial pressure (PPVL: +7%; BDL: +9%), and reduced heart rate (PPVL: ?10%; BDL: ?13%). Accordingly, splenectomized rats had lower von Willebrand factor plasma levels (PPVL: ?22%; BDL: ?25%). Splenectomy resulted in higher hemoglobin levels in PPVL (14.15 vs. 13.08 ?g/dL, p ?< ?0.001) and BDL (13.20 vs. 12.39 ?g/dL, p ?= ?0.097) animals, and significantly increased mean corpuscular hemoglobin concentrations (PPVL: +9%; BDL: +15%). Thrombocytopenia only developed in the PPVL model and was alleviated in the splenectomized subgroup. Conversely, BDL rats presented with thrombocytosis, which was not affected by splenectomy.ConclusionsSplenectomy improves both cirrhotic and non-cirrhotic PH, and ameliorates the hyperdynamic circulation. Hypersplenism related anemia and thrombocytopenia were only significantly improved in the non-cirrhotic PH model.     

Prehepatic portal hypertension worsens the enterohepatic redox balance in thioacetamide-cirrhotic rats

Background: Oxidative stress has been reported as a key pathogenic factor in many human liver diseases and in experimental models of cirrhosis related to hepatotoxin administration. The aim of this study was to verify the hypothesis that prehepatic portal hypertension aggravates the enterohepatic redox imbalance in thioacetamide-cirrhotic rats. Materials and methods: Wistar male rats were used: Control (n = 9); rats with prehepatic portal hypertension by triple partial portal vein ligation (TPVL; n = 9); thioacetamide-cirrhotic rats (TAA; n = 9) and TPVL-rats associated to TAA administration (TPVL + TAA; n = 9). Three months after the operation, portal pressure (PP), mesenteric venous vasculopathy (MVV) and portosystemic collateral circulation were studied. Liver and ileal levels of malondialdehyde (MDA), as a lipid peroxidation marker, and catalase (CAT), glutathione peroxidase (GSH-Px), glutathione transferase (GSH-t) and cytosolic and mitochondrial superoxide dismutases (cSOD and mSOD), as antioxidative enzymatic mechanisms, were measured. Results: Liver and ileal MDA increased in all the experimental groups, although the higher increase occurred in the ileum of rats with portal hypertension. CAT levels decreased in the liver and the ileum in the three experimental groups. The decrease in liver and ileal GSH-Px and GSH-t was greater in rats with portal hypertension, alone or associated with TAA. mSOD activation was demonstrated in the liver when portal hypertension was added to TAA. On the contrary, this compensatory response was not activated in the ileum, where mSOD was significantly decreased. Conclusion: Prehepatic portal hypertension by triple partial portal vein ligation impaired the enterohepatic antioxidative activity and aggravated the intestinal oxidative stress in thioacetamide-cirrhotic rats.     

门静脉高压症猪门静脉的生物力学特性及其临床意义

目的:建立猪门静脉高压症模型,探讨门静脉高压症时门静脉的生物力学特性。方法:采用2月龄湖北白种猪,用四氯化碳、苯巴比妥、乙醇,配合高脂、低蛋白、低胆碱饮食进行混合饲养。通过脾静脉插管测压,取门静脉在生物软组织力学试验机上测定其压力-直径关系,横断取材,冰冻切片,H E法染色,用计算机图像分析系统测量其几何形态学指标。结果:实验组门静脉压为(4.17±1.03)kPa,对照组为(1.51±0.79)kPa(P<0.01),实验组门静脉的Einc、Ep和EV均随压力的上升而增大,在相同压力下明显大于对照组的Einc、Ep和EV。在0～4 kPa压力范围内实验组门静脉的顺应性(C)显著低于对照组,而在4～8 kPa的高压时两者顺应性差异并不明显(P>0.05)。结论:门静脉高压症时,门静脉的生物力学特性均发生了明显变化。肝移植时,移植材料间的生物力学特性也应考虑。     

Histopathology of the liver in non-cirrhotic portal hypertension of unknown aetiology

Non-cirrhotic, long-standing portal hypertension of unknown aetiology is being re-evaluated histopathologically and clinically. In this study, we examined 107 livers with this condition (92 wedge biopsy and 15 autopsy specimens) from five institutions in Japan. These cases were histologically categorized into four groups: idiopathic portal hypertension (66 cases), nodular regenerative hyperplasia (14 cases), partial nodular transformation (two cases), and incomplete septal cirrhosis (25 cases). These four groups shared several histological features: dense portal fibrosis with portal venous obliteration and intralobular slender fibrosis. In addition, the histopathological features characteristic of one group were also found to a mild degree in other groups. The histopathological lesions preceding portal venous obliteration remain speculative. However, the portal venous obliteration may be responsible for the occurrence of sustained portal hypertension and several of the pathological changes in these livers. It seems likely that idiopathic portal hypertension, nodular regenerative hyperplasia, partial nodular transformation and incomplete septal cirrhosis comprise a family of non-cirrhotic, long-standing portal hypertension in Japan, and the histological differences between them may reflect chronological progression of a single disease.     

Helicobacter pylori,liver cirrhosis,and portal hypertension: an updated appraisal

Objective: Helicobacter pylori (H. pylori) is the most common cause of gastritis and peptic ulcer. However, H. pylori is even involved in extragastric diseases, and it has been hypothesized that H. pylori could be a risk factor for several hepatic diseases. For instance, a direct involvement of H. pylori in the development of portal hypertension (PH) in cirrhotic patients has been postulated.

Methods: We performed a literature search in major databases to elucidate the relationship between H. pylori, portal hypertension, and liver cirrhosis.

Results: The effect of H. pylori on PH may be multifactorial. Endothelial dysfunction, alterations in the vasodilating dynamics, and neoangiogenesis are the most appealing theories about this issue, but the proofs come mainly from experimental studies, therefore a solid pathophysiological basis is still to be demonstrated. Congestive gastropathy (CG) and gastric antral vascular ectasia (GAVE) are two common endoscopic entities responsible for acute/chronic upper gastrointestinal bleeding, and a link with H. pylori has been hypothesized: the gastric mucosa, exposed to H. pylori, could develop both inflammatory microcirculatory alterations and thrombi, resembling the histologic pattern of GAVE.

Conclusions: Despite clues for an association between H. pylori and PH have been shown, these evidences are mostly experimental, therefore, in the absence of a direct proof on human beings, the role of H. pylori in the development of PH is uncertain. However, since this germ may be a cause of peptic ulcer, it should be found and eradicated in cirrhotic patients to reduce the risk of blood loss anemia.     

A comparative histological and morphometric study of vascular changes in idiopathic portal hypertension and alcoholic fibrosis/cirrhosis

AIM: To examine the pathological changes of hepatic arteries in idiopathic portal hypertension (IPH) which is characterized by the obliteration of the intrahepatic portal vein branches and presinusoidal portal hypertension. METHODS AND RESULTS: Liver specimens (biopsied or surgically resected) from 20 patients with IPH, 20 patients with alcoholic fibrosis/cirrhosis (AF/C) and 20 histologically normal livers were used. The vascular lumina of arterial and venous vessels in portal tracts were morphometrically evaluated by an image analysis system. The ratio of portal venous luminal area to portal tract area (portal venous index) of IPH and that of AF/C were significantly reduced compared with normal liver. The portal venous index for IPH was significantly lower than that for AF/C. The ratio of hepatic arterial luminal area to portal tract area for AF/C was significantly higher than that in normal liver; however, that for IPH was similar to normal. The peribiliary vascular plexus was increased in AF/C but not in IPH. In AF/C, the number of mast cells and macrophages known to be the source of angiogenic substances was significantly increased in the portal tract compared with normal liver, while in IPH it was not increased. CONCLUSIONS: In AF/C, a reduction in portal venous lumen was associated with an increase of hepatic arterial lumen and of angiogenesis-related cells in portal tracts. However, such compensatory arterial changes were not evident in IPH, and this compensatory failure may be a feature of IPH.     

3D DCE MRP在评价肝硬化门脉高压症门静脉系统血管解剖及侧支循环的价值

目的:探讨三维动态对比增强磁共振门脉血管造影(3DDCEMRP)在肝硬化门脉高压症门静脉系统及门体侧支循环显像中的应用价值.方法:对19例肝硬化门脉高压症组病人及51例非肝硬化对照组行3DDCEMRP检查,测量门脉系统各主要干支的径线并比较两者差异;于3DDCEMRP检查前后10d内,对所有肝硬化症组患者行门脉间接造影,以其结果为标准,分析侧支循环发生的部位和分布范围,评价两者的符合情况.结果:肝硬化门脉高压症组MPV、SPV及SMV直径明显大于对照组(P<0.05),门脉分支级数明显减少;但Child A、B级患者间MPV直径及门脉分支级数的减少无明显差别(P>0.05).同时,3D DCE MRP显示2例门脉主干海绵样变并检出48条肝外侧支血管,与DSA结果相对照,除1例脐静脉开放及1例自发性脾肾分流未见显示外,其余侧支循环在3D DCE MRP 上均清楚显影,总符合率为96.0%(48/50).结论:3DDCEMRP能较好显示门脉系统的解剖影像,并对曲张静脉、侧支循环显影良好,也是诊断门脉海绵样变的有效方法.对于门脉高压症的诊断及手术治疗有重要指导意义.     

血管内皮细胞生长因子mRNA在门脉高压脾脏中的表达

目的 了解血管内皮细胞生长因子mRNA在门脉高压脾脏中的表达。方法 逆转录-聚合酶链反应(RT-PCR)技术检测20例门脉高压小鼠脾脏VEGFmRNA表达。结果 有18例巨脾组织表达VEGF mRNA,表达率为90％;2例无表达。对照组为零。两组间有显著差异(p<0.01).结论 VEGF在门脉高压所致的脾肿大中起重要作用,通过诱导内皮细胞通透性和内皮细胞的增生,促进脾脏的肿大。     

Bile duct adenoma and von Meyenburg complex‐like duct arising in hepatitis and cirrhosis: Pathogenesis and histological characteristics

Morphologic features and neoplastic potentials of bile duct adenoma (BDA) and von Meyenburg complex (VMC)‐like duct arising in chronic liver disease were unknown. Thirty‐five BDAs and 12 VMC‐like duct lesions were observed in 39 cases with chronic liver disease. BDAs were divided into the EMA‐cytoplasmic type (n = 14) and EMA‐luminal type (n = 21). EMA‐cytoplasmic BDA composed of a proliferation of cuboidal to low‐columnar cells forming an open lumen with NCAM(+)/MUC6(‐), resembling an interlobular bile duct. EMA‐luminal BDA showed uniform cuboidal cells with narrow lumen, and NCAM(++)/MUC6(++), resembling a ductular reaction. VMC‐like duct showed positive MUC1 expression and negative MUC6. The expression of S100P, glucose transporter‐1 (GLUT‐1) and insulin‐like growth factor II mRNA‐binding protein 3 (IMP‐3) were not detected in three lesions. p16 expression was higher than those of the ductular reaction, and the Ki67 and p53 indexes were very low (<1.0%). Large‐sized EMA‐luminal BDA shows sclerotic stroma. We classified small nodular lesions of ductal or ductular cells in chronic hepatitis and cirrhosis into the following groups: BDA, interlobular bile duct type; BDA, ductular/peribiliary gland type; and VMC‐like duct. They may be reactive proliferation rather than neoplastic lesions.     

肝硬化门脉高压症患者胃左静脉组织ET-1和NO的变化与静脉压的关系

目的探讨肝硬化门脉高压症患者胃左静脉组织中内皮素-1(ET-1)和一氧化氮(NO)比值的变化及其与胃左静脉压力的相关性。方法放射免疫法和硝酸酶还原法检测肝硬化门脉高压症患者及对照组患者胃左静脉组织中ET-1和NO含量,术中测定胃左静脉压力,比较两组ET-1/NO比值的变化,并对ET-1/NO比值与胃左静脉压力进行相关性分析。结果门脉高压症患者胃左静脉组织中ET-1/N0比值较对照组明显升高(P<0.05)。ET-1/N0比值与胃左静脉压力呈显著正相关关系(P<0.05)。结论肝硬化门脉高压症患者存在ET-1和NO失衡,ET-1产生相对过多,可能是门脉高压症形成和发展的重要原因之一。ET-1/N0比值与胃左静脉压力相关,可以用来间接反映门静脉压的高低,从而对预测曲张静脉破裂出血有一定的意义。     

Structural characteristic of splenic sinuses in idiopathic portal hypertension

Splenic sinuses in idiopathic portal hypertension (IPH; 8 patients}, liver cirrhosis (LC; 14 patients) and in regenerating autotransplanted spleens from 25 rats were compared with each other by scanning electron microscopy (SEM) and immunohistochemistry using antibodies against proliferating cell nuctear antigen (PCNA). Spleens obtained from six patients with gastric carcinoma and from five untreated adult rats were examined as controls. SEM of the sinuses showed that in IPH endothelial cells became irregular in shape, and the interendothelial slits of sinuses were irregularly entarged. Sinus endothelial processes traversing the sinusal lumen were also found. The same changes were observed in the proliferating sinuses during regeneration of splenic tissue after autotransplantation in rats, but disappeared when the regeneration was completed. Irregular endothelial cells were few in LC. PCNA-positive sinus endothelial cells were increased in number in IPH as compared with those in LC; the mean number of PCNA-positive ones per cm² was 45.4 in IPH and 8.2 in LC. It was suggested that, from SEM observation of sinus endothelial cells and counting PCNA-positive sinus endothelial cells, the sinuses of the spleen in IPH consist of proliferating endothelial cells or are in the state of increased proliferation. In conclusion, splenomegaly in IPH was presumed to be caused by proliferation of sinus endothelial cells, and by the increased splenic blood flow in the irregularly widened interendothelial slits of the sinuses.     

Three-dimensional structural changes of hepatic sinusoids in cirrhosis providing an increase in vascular resistance of portal hypertension

A quantitative topological analysis of the three-dimensional sinusoidal structure of five normal human livers and ten cirrhotic livers was performed with the aid of a computer system for reconstruction from serial tissue sections. The mean cycle rank (number of independent cycles) of the sinusoidal network in the examined tissue, 200 × 200 × 80 μm³ in size, was 181.2 ± 23.9 in the normal liver and 84.9 ± 19.1 in the cirrhotic liver. There was a statistically significant difference between the two values (P < 0.001), while there was no significant difference in the sinusoidal volume of the same size tissue between the normal liver and cirrhotic liver. It was found therefore that the sinusoidal network of the cirrhotic liver was more sparsely and coarsely connected in three-dimensional space than that of the normal liver. In addition, there was no significant difference in the mean sinusoidal radius or in the distribution of 1/(radius)⁴ values between the normal liver and the cirrhotic liver. Resistance changes of the lattice sinusoidal model, where resistance of each sinusoidal branch is proportional only to its length, were then studied. In the lattice model analysis, the resistance between the two endpoints becomes larger as the cycle rank of the network model decreases. This fact suggests that in portal hypertension of cirrhosis the three-dimensional structural change of sinusoids, that is, decrease in the cycle rank, plays a role of increased vascular resistance within regenerative nodules.     

辛伐他汀通过抑制p38 MAPK活化降低肝硬化门静脉高压大鼠门静脉压力

 目的:探讨p38 MAPK信号通路在辛伐他汀降低肝硬化门静脉高压症大鼠门静脉压力（PP）中的作用。方法:采用四氯化碳复合因素法构建大鼠肝硬化门静脉高压症模型,成模后将存活大鼠随机分为模型组（n=10）、辛伐他汀治疗组（n=11）和p38 MAPK信号通路抑制剂SB203580处理组（n=10）,后2组分别给予辛伐他汀及SB203580干预处理;另设正常对照组（n=8）。处理结束后检测大鼠PP、肝脏总p38 MAPK蛋白、磷酸化p38 MAPK蛋白、总eNOS蛋白、磷酸化eNOS蛋白表达水平以及肝脏一氧化氮（NO）含量的变化。结果:（1）模型组大鼠PP明显高于正常对照组;辛伐他汀治疗组及SB203580处理组PP均明显低于模型组（P＜0.01）,辛伐他汀治疗组PP明显低于SB203580处理组（P＜0.01）。（2）与正常大鼠相比,模型组大鼠肝脏总p38 MAPK蛋白及总eNOS蛋白表达水平无明显变化（P＞0.05）,而磷酸化p38 MAPK蛋白及磷酸化eNOS蛋白表达水平分别增高与降低（P＜0.01）;辛伐他汀治疗组大鼠肝脏磷酸化p38 MAPK蛋白及磷酸化eNOS蛋白表达水平分别降低与增高（P＜0.01）;SB203580处理组大鼠肝脏磷酸化p38 MAPK蛋白及磷酸化eNOS蛋白表达水平分别降低与增高（P＜0.01）,但磷酸化eNOS蛋白表达水平增高的程度低于辛伐他汀治疗组（P＜0.01）。(3)辛伐他汀治疗组肝脏NO含量［（15.73±1.59） μmol/(g protein)］及SB203580处理组肝脏NO含量［（13.98±1.27) μmol/(g protein)］明显高于模型组［（9.81±1.12） μmol/（g protein）］（P＜0.01）,辛伐他汀治疗组NO含量明显高于SB203580处理组（P＜0.01）。结论: 辛伐他汀降低肝硬化门静脉高压症大鼠门静脉压力可能与其抑制p38 MAPK信号通路的活化有关。     

An intravital microscopic study of the hepatic microcirculation in cirrhotic mice models: relationship between fibrosis and angiogenesis

This intravital fluorescence microscopy (IVFM) study validates cirrhotic mice models and describes the different intrahepatic alterations and the role of angiogenesis in the liver during genesis of cirrhosis. Cirrhosis was induced by subcutaneous injection of carbon tetrachloride (CCl₄) and by common bile duct ligation (CBDL) in mice. Diameters of sinusoids, portal venules (PV), central venules (CV) and shunts were measured at different time points by IVFM. Thereafter, liver samples were taken for sirius red, CD31, Ki67, vascular endothelial growth factor (VEGF) and α‐smooth muscle actin (α‐SMA) evaluation by immunohistochemistry (IHC). In parallel with fibrogenesis, hepatic microcirculation was markedly disturbed in CCl₄ and CBDL mice with a significant decrease in sinusoidal diameter compared to control mice. In CCl₄ mice, CV were enlarged, with marked sinusoidal‐free spaces around CV. In contrast, PV were enlarged in CBDL mice and bile lakes were observed. In both mice models, intrahepatic shunts developed gradually after induction. During genesis of cirrhosis using CD31 IHC we observed a progressive increase in the number of blood vessels within the fibrotic septa area and a progressively increase in staining by Ki67, VEGF and α‐SMA of endothelial cells, hepatocytes and hepatic stellate cells respectively. In vivo study of the hepatic microcirculation demonstrated a totally disturbed intrahepatic architecture, with narrowing of sinusoids in both cirrhotic mice models. The diameters of CV and PV increased and large shunts, bypassing the sinusoids, were seen after both CCl₄ and CBDL induction. Thus present study shows that there is angiogenesis in the liver during cirrhogenesis, and this is probably due partially to an increased production of VEGF.     

Histology of portal vascular changes associated with idiopathic non‐cirrhotic portal hypertension: nomenclature and definition

Idiopathic non‐cirrhotic portal hypertension (INCPH) is a rare vascular liver disease that has attracted new interest in recent years. It is characterised by clinical signs of portal hypertension in the absence of cirrhosis or severe fibrosis and any known cause of portal hypertension. As much uncertainty exists about INCPH pathophysiology, and no definite diagnostic tests are available, liver biopsy is an essential tool for achieving a definite diagnosis. Unfortunately, the histological diagnosis of INCPH is not always straightforward, as the characteristic lesions are unevenly distributed, vary greatly in their severity, are often very subtle, and are not all necessarily present in a single case. Furthermore, specifically for the characteristic portal vessel changes observed in INCPH, the terminology and definition are ambiguous, which adds complexity to the already complex clinicopathological scenario. An international study group of liver pathologists and hepatologists pursued a consensus on nomenclature for the portal vascular lesions of INCPH. Such standardisation may assist pathologists in the recognition of such lesions, and will possibly facilitate further advancement in this field.     

Cell cycle perturbation in the hepatocytes of HCV core transgenic mice following common bile duct ligation is associated with enhanced p21 expression

Hepatitis C virus (HCV) core protein has been reported to alter the cell cycle in vitro, but the data remain inconclusive, and in vitro experiments do not represent precisely events that occur in vivo, which may involve hepatic inflammation or regeneration. A group of double‐transgenic mice carrying tetracycline transactivator (tTA) and HCV core that express conditionally the HCV core in the mature liver, and single‐transgenic mice carrying only tTA were subjected to sham laparotomy, 43% partial hepatectomy, or common bile duct ligation. The cell cycle markers, including cyclin A, B1, D, E1, Mcm‐2, phosphorylated histone 3 protein, Ki67, and p21Waf1/Cip1/Sdi1 (p21), were evaluated in liver samples obtained 3 days after the operation. No significant differences in the levels of any markers were observed between the double‐ and single‐transgenic mice following sham laparotomy. Among the mice that underwent common bile duct ligation, the double‐transgenic mice had lower levels of Ki67 (P = 0.0001), higher levels of cyclin D1 (P = 0.0001), and higher levels of p21 expression than the single‐transgenic mice. Among those that underwent partial hepatectomy, the double‐transgenic mice had higher p21 expression levels, but no significant differences in the levels of any other markers were observed between the double‐ and single‐transgenic mice. It is concluded that the HCV core alters the hepatocyte cell cycle in addition to inducing G1 arrest in vivo after common bile duct ligation, and is associated with enhanced p21 expression. This may account at least partially for the strong association between HCV‐related hepatocarcinogenesis and hepatic inflammation/ fibrosis. J. Med. Virol. 81:467–472, 2009. © 2009 Wiley‐Liss, Inc.     

Berry splenic artery aneurysm rupture in association with segmental arterial mediolysis and portal hypertension

A rare case of berry splenic artery aneurysm (SAA) rupture associated with segmental arterial mediolysis (SAM) and portal hypertension is reported. A 66-year-old woman, diagnosed as having liver cirrhosis and portal hypertension 6 years earlier, suddenly developed a lancinating pain in the upper abdomen and lost consciousness. She recovered consciousness while being transferred to hospital by ambulance. During the investigations, her level of consciousness suddenly deteriorated. Ultrasonography showed a massive intraperitoneal hemorrhage, and she died 5(1/2) h after admission. On gross examination at autopsy it was not possible to find the rupture point of the vessel because the pancreas was embedded in a massive hematoma. However, careful dissection of the pancreatic tail after fixation revealed a berry aneurysm measuring 0.8 cm in diameter in a branch adjacent to the bifurcation in the distal third of the main splenic artery. Microscopic examination detected a rupture of the aneurysm. The histology of the arterial wall proximal to the aneurysm showed typical SAM. In general, berry SAA caused by SAM is rare and unlikely to rupture. The SAA in the present case likely occurred and ruptured due to the combination of SAM and portal hypertension.