Establishment of a hepatic cirrhosis and portal hypertension model by hepatic arterial perfusion with 80% alcohol

Experimental model of portal hypertension and esophagogastric varices in minipigs: pressure and endoscopic pilot study

INTRODUCTION

Portal hypertension still represents an important health problem worldwide. In the search for knowledge regarding this syndrome, experimental studies with animal models have proven to be useful to point the direction to be taken in future randomized clinical trials.

PURPOSE

To validate the experimental model of portal hypertension and esophagogastric varices in a medium-sized animal.

METHODS

This study included five minipigs br1. Midline laparotomy with dissection of the portal vein and production of a calibrated stenosis of this vein was performed. Measurement of pressure in the portal venous and digestive endoscopic were performed before and five weeks after the production of a stenosis.

RESULTS

All animals were 8 months old, average weight of 17 ± 2.5 kg. The mean pressure of the portal vein immediately before the partial ligation of the portal vein was 8.9 + 1.6 mm Hg, with 26.6 + 5.4 mm Hg in the second measurement five weeks later (p < 0.05). No gastroesophageal varices or hypertensive portal gastropathy were seen at endoscopy procedures in our sample at any time in the study.

CONCLUSION

Portal vein ligation in minipigs has been validated in the production of portal hypertension, but not in the formation of esophageal varices.

Novel imaging-based approaches for predicting the hepatic venous pressure gradient in a porcine model of liver cirrhosis and portal hypertension

AIMS

Hepatic venous pressure gradient (HVPG) is critical for staging and prognosis prediction of portal hypertension (PH). However, HVPG measurement has limitations (e.g., invasiveness). This study examined the value of non-invasive, imaging-based approaches including magnetic resonance elastography (MRE) and intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) for the prediction of HVPG in a porcine model of liver cirrhosis and PH.

MAIN METHODS

Male Bama miniature pigs were used to establish a porcine model of liver cirrhosis and PH induced by embolization. They were randomly assigned to an experimental group (n = 12) and control group (n = 3). HVPG was examined before and after transjugular intrahepatic portosystemic shunt (TIPS). MRE and IVIM-DWI were performed to obtain quantitative parameters including liver stiffness (LS) in MRE, tissue diffusivity (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f) in IVIM-DWI. The correlation between HVPG and the parameters was assessed.

KEY FINDINGS

LS values were significantly greater in the experimental group, while f values were significantly decreased at 4, 8, and 12 weeks after embolization compared to the control group. Furthermore, HVPG was significantly lower immediately after versus before TIPS. In parallel, LS and f values showed significant alterations after TIPS, and these changes were consistent with a reduction in HVPG. Spearman analysis revealed a significant correlation between the parameters (LS and f) and HVPG. The equation was eventually generated for prediction of HVPG.

SIGNIFICANCE

The findings show a good correlation between HVPG and the quantitative parameters; thus, imaging-based techniques have potential as non-invasive methods for predicting HVPG.

Hypochlorite-induced porcine model of peritoneal fibrosis through the activation of IL1β-CX3CL1-TGFβ1 signal axis

Patients with kidney failure rely on life-saving peritoneal dialysis to facilitate waste exchange and maintain homeostasis of physical conditions. However, peritoneal dialysis often results in peritoneal fibrosis and organ adhesion that subsequently compromise the efficiency of peritoneal dialysis and normal functions of visceral organs. Despite rodent models provide clues on the pathogenesis of peritoneal fibrosis, no current large animal model which shares high degree of physiological and anatomical similarities to human is available, limiting their applications on the evaluation of pre-clinical therapeutic efficacy. Here we established for the first time, hypochlorite-induced porcine model of peritoneal fibrosis in 5-week-old piglets. We showed that administration 15–30 mM hypochlorite, a dose- and time-dependent severity of peritoneal fibrosis characterized by mesothelium fragmentation, αSMA⁺ myofibroblasts accumulation, organ surface thickening and type I collagen deposition were observed. We also demonstrated in vitro using human mesothelial cells that hypochlorite-induced fibrosis was likely due to necrosis, but not programmed apoptosis; besides, overexpression of IL1β, CX3CL1 and TGFβ on the peritoneal mesothelium in current model was detected, similar to observations from peritoneal dialysis-induced peritoneal fibrosis in human patients and earlier reported mouse model. Moreover, our novel antemortem evaluation using laparoscopy provided instant feedback on the progression of organ fibrosis/adhesion which allows immediate adjustments on treatment protocols and strategies in alive individuals that can not and never be performed in other animal models.

Hepatic regeneration following radiation-induced liver injury is associated with increased hepatobiliary secretion measured by PET in Göttingen minipigs

Normal liver tissue is highly vulnerable towards irradiation, which remains a challenge in radiotherapy of hepatic tumours. Here, we examined the effects of radiation-induced liver injury on two specific liver functions and hepatocellular regeneration in a minipig model. Five Göttingen minipigs were exposed to whole-liver stereotactic body radiation therapy (SBRT) in one fraction (14 Gy) and examined 4–5 weeks after; five pigs were used as controls. All pigs underwent in vivo positron emission tomography (PET) studies of the liver using the conjugated bile acid tracer [N-methyl-¹¹C]cholylsarcosine ([¹¹C]CSar) and the galactose-analogue tracer [¹⁸F]fluoro-2-deoxy-d-galactose ([¹⁸F]FDGal). Liver tissue samples were evaluated histopathologically and by immunohistochemical assessment of hepatocellular mitosis, proliferation and apoptosis. Compared with controls, both the rate constant for secretion of [¹¹C]CSar from hepatocytes into intrahepatic bile ducts as well as back into blood were doubled in irradiated pigs, which resulted in reduced residence time of [¹¹C]CSar inside the hepatocytes. Also, the hepatic systemic clearance of [¹⁸F]FDGal in irradiated pigs was slightly increased, and hepatocellular regeneration was increased by a threefold. In conclusion, parenchymal injury and increased regeneration after whole-liver irradiation was associated with enhanced hepatobiliary secretion of bile acids. Whole-liver SBRT in minipigs ultimately represents a potential large animal model of radiation-induced liver injury and for testing of normal tissue protection methods.

Long-term Functional Maintenance of Exteriorized Portal Venous Catheters in a Porcine Animal Model

BACKGROUND

Portal venous access for blood sampling, infusion therapy, and measurement of portal venous pressure is of special interest for experimental studies in surgery, pharmacology, and hepatology. Chronic animal models with continuous portal venous access are rare and especially thrombosis or clotting of permanent catheters is a frequent complication. Aim of this study was to establish a preclinical pig model with a permanent portal venous catheter (PVC).

MATERIALS AND METHODS

PVC implantation was performed in 21 LEWE mini pigs. The catheter was inserted in the distal part of the superior mesenteric vein and fixated with a tobacco-pouch suture. Animals were followed up for 4 wk, directly after implantation of the PVC. Blood gas analyses and portal venous pressures were recorded. Three different groups with continuous infusion via the catheters were defined: NaCl solution (2 mL/h) (group 1), NaCl solution (2 mL/h) + enoxaparin sodium injection (anti-Xa levels of 0.3-0.8 U/mL) (group 2) and heparinized NaCl (2 I.E./mL, 2 mL/h) (group 3).

RESULTS

All 21 PVC implantations were performed without any complications. Application of continuous perfusion with heparinized NaCl (group 3) enabled portal venous access for the entire experiment in 8 of 10 cases (mean of 23.7 d) without any signs of dysfunction. However, for use of NaCl alone or in combination with enoxaparin sodium, catheters were only functional for 6.8 d and 6.9 d, respectively.

CONCLUSIONS

Permanent portal venous access through PVC in mini pigs is achievable by continuous infusion of low-dose heparinized NaCl solution.

Study of liver in HBV-related hepatocellular carcinoma: Stereology shows quantitative differences in liver structure

Hepatocellular carcinoma is one of the main consequences of liver chronic disease. Hepatocellular carcinoma-related changes may be seen in patients with chronic hepatitis B. The aim of the current study was to quantitate liver tissue elements by stereological technique in patients with hepatitis B-related cancer and compare the results with control and only hepatitis B group. Needle liver biopsies from 40 patients with only chronic hepatitis B infection, from 41 patients with only early hepatocellular carcinoma, from 40 patients with early hepatitis B-related cancer and 30 healthy subjects (control group) were analyzed by stereological method using systematic uniform random sampling method. Haematoxylin and eosin stained sections were used. The numerical density of hepatocytes, hepatocyte volume, numerical density of Kupffer cells, volume density of the connective tissue in the portal space, and volume density of the connective tissue were assessed. Quantitative analysis of liver samples indicated that there were statistically significant differences in the numerical density of hepatocytes, hepatocyte volume, numerical density of Kupffer cells, volume density of the connective tissue in the portal space, and volume density of the connective tissue between control and hepatitis B-related cancer and hepatitis B groups. Quantitative, stereological technique is simple and reliable for evaluating HCC in chronic hepatitis B. It is useful for assessing the liver tissue parameters. Stereology is recommended for the diagnosis of people prone to cancer in patients with chronic hepatitis B.

Effect of yoga and naturopathy on liver, renal and cardiorespiratory functions of a patient with hepatic cirrhosis with portal hypertension and ascites: a case report

A 39-year-old, married man was diagnosed with hepatic cirrhosis with portal hypertension and ascites in February 2016. His symptoms as described by him began with generalized body weakness, breathlessness and sudden weight gain of 16 kg within 3 weeks. History of regular intake of alcohol since 7 years and tremendous family stress were present. Patient underwent conventional medication for 6 months and ayurvedic medications for 4 months. In January 2017, he visited our hospital with the same complaints and underwent integrated naturopathy and yoga therapies (INYTs) for 4 weeks along with Ayurveda and conventional medications. The results of this study showed a better reduction in body weight, body mass index, abdominal girth, systolic blood pressure and diastolic blood pressure along with improvement in breath holding time, hemoglobin level, liver function test and renal function test. It suggests that 4 weeks of INYT with Ayurveda and conventional medications was effective in patients with hepatic cirrhosis with portal hypertension and ascites. Further studies are required to warrant these results.

Distribution of Connective Tissue in the Male and Female Porcine Liver: Histological Mapping and Recommendations for Sampling

The pig is a large animal model that is often used in experimental medicine. The aim of this study was to assess, in normal pig livers, sexual dimorphism in the normal fraction of hepatic interlobular and intralobular connective tissue (CT) in six hepatic lobes and in three macroscopical regions of interest (ROIs) with different positions relative to the liver vasculature. Using stereological point grids, the fractions of CT were quantified in histological sections stained with aniline blue and nuclear fast red. Samples (415 tissue blocks) were collected from healthy piglets, representing paracaval, paraportal and peripheral ROIs. There was considerable variability in the CT fraction at all sampling levels. In males the mean fraction of interlobular CT was 4.7 ± 2.4% (mean ± SD) and ranged from 0% to 11.4%. In females the mean fraction of the interlobular CT was 3.6 ± 2.2% and ranged from 0% to 12.3%. The mean fraction of intralobular (perisinusoidal summed with pericentral) CT was <0.2% in both sexes. The interlobular CT represented >99.8% of the total hepatic CT and the fractions were highly correlated (Spearman r = 0.998, P <0.05). The smallest CT fraction was observed in the left medial lobe and in the paracaval ROI and the largest CT fraction was detected in the quadrate lobe and in the peripheral ROI. For planning experiments involving the histological quantification of liver fibrosis and requiring comparison between the liver lobes, these data facilitate the power analysis for sample size needed to detect the expected relative increase or decrease in the fraction of CT.

The portal hypertension syndrome: etiology, classification, relevance, and animal models

BACKGROUND

Portal hypertension is a key complication of portal hypertension, which is responsible for the development of varices, ascites, bleeding, and hepatic encephalopathy, which, in turn, cause a high mortality and requirement for liver transplantation.

AIM

This review deals with the present day state-of-the-art preventative treatments of portal hypertension in cirrhosis according to disease stage. Two main disease stages are considered, compensated and decompensated cirrhosis, the first having good prognosis and being mostly asymptomatic, and the second being heralded by the appearance of bleeding or non-bleeding complications of portal hypertension.

RESULTS

The aim of treatment in compensated cirrhosis is preventing clinical decompensation, the more frequent event being ascites, followed by variceal bleeding and hepatic encephalopathy. Complications are mainly driven by an increase of hepatic vein pressure gradient (HVPG) to values ≥10 mmHg (defining the presence of Clinically Significant Portal Hypertension, CSPH). Before CSPH, the treatment is limited to etiologic treatment of cirrhosis and healthy life style (abstain from alcohol, avoid/correct obesity…). When CSPH is present, association of a non-selective beta-blocker (NSBB), including carvedilol should be considered. NSBBs are mandatory if moderate/large varices are present. Patients should also enter a screening program for hepatocellular carcinoma. In decompensated patients, the goal is to prevent further bleeding if the only manifestation of decompensation was a bleeding episode, but to prevent liver transplantation and death in the common scenario where patients have manifested first non-bleeding complications. Treatment is based on the same principles (healthy life style..) associated with administration of NSBBs in combination if possible with endoscopic band ligation if there has been variceal bleeding, and complemented with simvastatin administration (20-40 mg per day in Child-Pugh A/B, 10-20 mg in Child C). Recurrence shall be treated with TIPS. TIPS might be indicated earlier in patients with: 1) Difficult/refractory ascites, who are not the best candidates for NSBBs, 2) patients having bleed under NSBBs or showing no HVPG response (decrease in HVPG of at least 20% of baseline or to values equal or below 12 mmHg). Decompensated patients shall all be considered as potential candidates for liver transplantation.

CONCLUSION

Treatment of portal hypertension has markedly improved in recent years. The present day therapy is based on accurate risk stratification according to disease stage.