Experimental obstructive cholestasis: the wound-like inflammatory liver response. Fibrogenesis Tissue Repair. 2008;1:6. [PMID: 19014418 PMCID: PMC2637833 DOI: 10.1186/1755-1536-1-6]

Synergetic Effect of Lupeol and Naringin Against Bile Duct Ligation Induced Cardiac Injury in Rats via Modulating Nitrite Level (eNos) and NF-kB /p65 Expression

Cardiac dysfunction such as cirrhotic cardiomyopathy is more common in liver cirrhosis related disorders including primary biliary cholangitis or biliary cirrhosis and primary sclerosing cholangitis. Bile duct ligation (BDL) is an effective model of biliary cholestasis, producing oxidative damage and fibrosis. This research was designed to evaluate the effect of Lupeol and Naringin and its combination on bile duct ligation induced cardiac injury in rats. For pharmacological evaluation, rats were randomly divided into seven groups; intrahepatic cholestasis induced by ligation of the bile duct might lead to cirrhotic cardiomyopathy. The results were analyzed by physical, biochemical and histological examination. The Lupeol (100 mg/kg, p.o.), Naringin (100 mg/kg, p.o.) and its combination (100 mg/kg each) treated group significantly improved physical infarct size, biochemical (Nitrite, SOD, CAT, and GSH) and histological (heart tissue- mitochondrial function/integrity and fibrosis) alterations occurs due to BDL-ligation. This study was concluded that oral administration of Lupeol, Naringin, and its combination has a curative potential against BDL-induced cardiac injury in rats by reducing oxidative stress and inflammatory reactions, resulting in reduced heart necrosis/myocardial infarction and increased myocardial activity. It also inhibits cardiac damage in the rat heart, these effects may be linked to the NO level (eNOS) is increased and the inactivation of the NF-kB-p65 expression pathways.This study also provides new insights into the development of lupeol and Naringin combination that can be used as supportive therapy for cardiovascular diseases.

Relationships between congenital peritoneopericardial diaphragmatic hernia or congenital central diaphragmatic hernia and ductal plate malformations in dogs and cats

OBJECTIVE

To characterize the association between peritoneopericardial diaphragmatic hernia (PPDH) or congenital central diaphragmatic hernia (CCDH) and ductal plate malformations (DPMs) in dogs and cats.

ANIMALS

18 dogs and 18 cats with PPDH or CCDH and 19 dogs and 18 cats without PPDH or CCDH.

PROCEDURES

Evaluation of clinical details verified PPDH or CCDH and survival times. Histologic features of nonherniated liver samples were used to categorize DPM. Immunohistochemical staining for cytokeratin-19 distinguished bile duct profiles per portal tract and for Ki-67-assessed cholangiocyte proliferation. Histologic features of herniated liver samples from PPDH or CCDH were compared with those of pathological controls (traumatic diaphragmatic hernia, n = 6; liver lobe torsion, 6; ischemic hepatopathy, 2).

RESULTS

DPM occurred in 13 of 18 dogs with the proliferative-like phenotype predominating and in 15 of 18 cats with evenly distributed proliferative-like and Caroli phenotypes. Congenital hepatic fibrosis DPM was noted in 3 dogs and 2 cats and renal DPM in 3 dogs and 3 cats. No signalment, clinical signs, or clinicopathologic features discriminated DPM. Kaplan Meier survival curves were similar in dogs and cats. Bile duct profiles per portal tract in dogs (median, 5.0; range, 1.4 to 100.8) and cats (6.6; 1.9 to 11.0) with congenital diaphragmatic hernias significantly exceeded those in healthy dogs (1.4; 1.2 to 1.6) and cats (2.3; 1.7 to 2.6). Animals with DPM lacked active cholangiocyte proliferation. Histologic features characterizing malformative bile duct profiles yet without biliary proliferation were preserved in herniated liver lobes in animals with DPM.

CONCLUSIONS AND CLINICAL RELEVANCE

DPM was strongly associated with PPDH and CCDH. Because DPM can impact health, awareness of its coexistence with PPDH or CCDH should prompt biopsy of nonherniated liver tissue during surgical correction of PPDH and CCDH.

Stable Gastric Pentadecapeptide BPC 157 and Wound Healing

Significance: The antiulcer peptide, stable gastric pentadecapeptide BPC 157 (previously employed in ulcerative colitis and multiple sclerosis trials, no reported toxicity (LD1 not achieved)), is reviewed, focusing on the particular skin wound therapy, incisional/excisional wound, deep burns, diabetic ulcers, and alkali burns, which may be generalized to the other tissues healing.

Recent Advances: BPC 157 has practical applicability (given alone, with the same dose range, and same equipotent routes of application, regardless the injury tested).

Critical Issues: By simultaneously curing cutaneous and other tissue wounds (colocutaneous, gastrocutaneous, esophagocutaneous, duodenocutaneous, vesicovaginal, and rectovaginal) in rats, the potency of BPC 157 is evident. Healing of the wounds is accomplished by resolution of vessel constriction, the primary platelet plug, the fibrin mesh which acts to stabilize the platelet plug, and resolution of the clot. Thereby, BPC 157 is effective in wound healing much like it is effective in counteracting bleeding disorders, produced by amputation, and/or anticoagulants application. Likewise, BPC 157 may prevent and/or attenuate or eliminate, thus, counteract both arterial and venous thrombosis. Then, confronted with obstructed vessels, there is circumvention of the occlusion, which may be the particular action of BPC 157 in ischemia/reperfusion.

Future Directions: BPC 157 rapidly increases various genes expression in rat excision skin wound. This would define the healing in the other tissues, that is, gastrointestinal tract, tendon, ligament, muscle, bone, nerve, spinal cord, cornea (maintained transparency), and blood vessels, seen with BPC 157 therapy.

The effect of Ankaferd blood stopper on liver damage in experimental obstructive jaundice

Background/aims

To evaluate the potential protective effects of Ankaferd blood stopper (ABS) in an experimental obstructive jaundice (OJ) model.

Materials and methods

The study included 26 female rats, which were divided into 3 groups. The sham group, consisting of 10 rats, (group 1) only received solely laparotomy. In the control group, consisting of 8 rats, (group 2), ligation was applied to the biliary tract and no treatment was implemented. In the treatment group, consisting of 8 rats, (group 3), following ligation of biliary tract, 0.5 mL/day ABS was given for 10 days. Liver tissue and blood samples were taken for histopathological and biochemical examination.

Results

Compared to group 2, group 3 had higher aspartate aminotransferase (AST), total oxidant status (TOS) malondialdehyde (MDA), fluorescent oxidant products (FOP), and lower expression of albumin and total antioxidant status (TAS) (P < 0.05). In histopathological analysis, the mean scores of all histopathological parameters (fibrosis, portal inflammation, confluent necrosis, interphase activity, bile duct proliferation) have statistical significance between group 2 and group 3 (P < 005).

Conclusions

ABS has promising results in the treatment of experimental OJ because of its antioxidant and antiinflammatory properties. It may be used in clinical practice after more extensive studies about the effects of ABS on OJ.

Metabolism in Acute-On-Chronic Liver Failure: The Solution More than the Problem

Chronic inflammatory liver disease with an acute deterioration of liver function is named acute-on-chronic inflammation and could be regulated by the metabolic impairments related to the liver dysfunction. In this way, the experimental cholestasis model is excellent for studying metabolism in both types of inflammatory responses. Along the evolution of this model, the rats develop biliary fibrosis and an acute-on-chronic decompensation. The acute decompensation of the liver disease is associated with encephalopathy, ascites, acute renal failure, an acute phase response and a splanchnic increase of pro- and anti-inflammatory cytokines. This multiorgan inflammatory dysfunction is mainly associated with a splanchnic and systemic metabolic switch with dedifferentiation of the epithelial, endothelial and mesothelial splanchnic barriers. Furthermore, a splanchnic infiltration by mast cells occurs, which suggests that these cells could carry out a compensatory metabolic role, especially through the modulation of hepatic and extrahepatic mitochondrial-peroxisome crosstalk. For this reason, we propose the hypothesis that mastocytosis in the acute-on-chronic hepatic insufficiency could represent the development of a survival metabolic mechanisms that mitigates the noxious effect of the hepatic functional deficit. A better understanding the pathophysiological response of the mast cells in liver insufficiency and portal hypertension would help to find new pathways for decreasing the high morbidity and mortality rate of these patients.

Mast cell-mediated splanchnic cholestatic inflammation

INTRODUCTION

Splanchnic mast cells increase in chronic liver and in acute-on-chronic liver diseases. We administered Ketotifen, a mast cell stabilizer, and measured the mast cells in the splanchnic organs of cholestatic rats.

MATERIAL AND METHODS

These groups were studied: sham-operated rats (S; n = 15), untreated microsurgical cholestasic rats (C; n = 20) and rats treated with Ketotifen: early (SK-e; n = 20 and CKe; n = 18), and late (SK-l; n = 15 and CK-l; n = 14).

RESULTS

The cholestatic rats showed systemic and splanchnic impairments, such as ascites, portal hypertension, and biliary proliferation and fibrosis. The rats also showed a splanchnic increase of TNF-α, IL-1β and MCP-1, and a reduction of IL-4, IL-10 and antioxidants. An increase of VEGF in the ileum and mesenteric lymphatic complex was associated with a liver reduction of TGF-β1. Ketotifen reduces the degree of hepatic insufficiency and the splanchnic inflammatory mediators, as well as VEGF and TGF-ß1 levels. Ketotifen also reduces the connective tissue mast cells in the mesenteric lymphatic complex of cholestatic rats, while increases the hepatic mucosal mast cells.

CONCLUSIONS

In cholestatic rats, Ketotifen improves liver function and ascites, and also reduces pro-inflammatory mediators in the splanchnic area. The decrease in connective tissue mast cells in the mesenteric lymphatic complex due to the administration of Ketotifen would lead to the improvement of the inflammatory splanchnic response, and consequently the abovementioned complications.

Protein tyrosine phosphatase 1b deficiency protects against hepatic fibrosis by modulating nadph oxidases

Inflammation is typically associated with the development of fibrosis, cirrhosis and hepatocellular carcinoma. The key role of protein tyrosine phosphatase 1B (PTP1B) in inflammatory responses has focused this study in understanding its implication in liver fibrosis. Here we show that hepatic PTP1B mRNA expression increased after bile duct ligation (BDL), while BDL-induced liver fibrosis was markedly reduced in mice lacking Ptpn1 (PTP1B^−/−) as assessed by decreased collagen deposition and α-smooth muscle actin (α-SMA) expression. PTP1B^−/− mice also showed a significant increase in mRNA levels of key markers of monocytes recruitment (Cd68, Adgre1 and Ccl2) compared to their wild-type (PTP1B^+/+) littermates at early stages of injury after BDL. Interestingly, the lack of PTP1B strongly increased the NADPH oxidase (NOX) subunits Nox1/Nox4 ratio and downregulated Cybb expression after BDL, revealing a pro-survival pattern of NADPH oxidase induction in response to liver injury. Chimeric mice generated by transplantation of PTP1B^−/− bone marrow (BM) into irradiated PTP1B^+/+ mice revealed similar hepatic expression profile of NOX subunits than PTP1B^−/− mice while these animals did not show differences in infiltration of myeloid cells at 7 days post-BDL, suggesting that PTP1B deletion in other liver cells is necessary for boosting the early inflammatory response to the BDL. PTP1B^−/− BM transplantation into PTP1B^+/+ mice also led to a blockade of TGF-β and α-SMA induction after BDL. In vitro experiments demonstrated that deficiency of PTP1B in hepatocytes protects against bile acid-induced apoptosis and abrogates hepatic stellate cells (HSC) activation, an effect ameliorated by NOX1 inhibition. In conclusion, our results have revealed that the lack of PTP1B switches NOX expression pattern in response to liver injury after BDL and reduces HSC activation and liver fibrosis.

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PTP1B deficiency in mice ameliorates liver damage induced by cholestasis.

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The increased NOX1/NOX4 ratio in livers from PTP1B^-/- mice was associated with protection against BDL-induced fibrosis.

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The lack of PTP1B exacerbates macrophage recruitment upon BDL which is dispensable for ameliorating cholestatic liver damage.

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Resistance of PTP1B^-/- hepatocytes against bile acid-induced apoptosis protects from HSC activation in a NOX1-dependent manner.

Acute-on-chronic liver disease enhances phenylephrine-induced endothelial nitric oxide release in rat mesenteric resistance arteries through enhanced PKA, PI3K/AKT and cGMP signalling pathways

Acute-on-chronic liver disease is a clinical syndrome characterized by decompensated liver fibrosis, portal hypertension and splanchnic hyperdynamic circulation. We aimed to determine whether the alpha-1 agonist phenylephrine (Phe) facilitates endothelial nitric oxide (NO) release by mesenteric resistance arteries (MRA) in rats subjected to an experimental microsurgical obstructive liver cholestasis model (LC). Sham-operated (SO) and LC rats were maintained for eight postoperative weeks. Phe-induced vasoconstriction (in the presence/absence of the NO synthase –NOS- inhibitor L-NAME) and vasodilator response to NO donor DEA-NO were analysed. Phe-induced NO release was determined in the presence/absence of either H89 (protein kinase –PK- A inhibitor) or LY 294002 (PI3K inhibitor). PKA and PKG activities, alpha-1 adrenoceptor, endothelial NOS (eNOS), PI3K, AKT and soluble guanylate cyclase (sGC) subunit expressions, as well as eNOS and AKT phosphorylation, were determined. The results show that LC blunted Phe-induced vasoconstriction, and enhanced DEA-NO-induced vasodilation. L-NAME increased the Phe-induced contraction largely in LC animals. The Phe-induced NO release was greater in MRA from LC animals. Both H89 and LY 294002 reduced NO release in LC. Alpha-1 adrenoceptor, eNOS, PI3K and AKT expressions were unchanged, but sGC subunit expression, eNOS and AKT phosphorylation and the activities of PKA and PKG were higher in MRA from LC animals. In summary, these mechanisms may help maintaining splanchnic vasodilation and hypotension observed in decompensated LC.

Stable gastric pentadecapeptide BPC 157 in the therapy of the rats with bile duct ligation

Recently, stable gastric pentadecapeptide BPC 157 reversed the high MDA- and NO-tissue values to the healthy levels. Thereby, BPC 157 therapy cured rats with bile duct ligation (BDL) (sacrifice at 2, 4, 6, 8 week). BPC 157-medication (10 μg/kg, 10 ng/kg) was continuously in drinking water (0.16 μg/ml, 0.16 ng/ml, 12 ml/rat/day) since awakening from surgery, or since week 4. Intraperitoneal administration was first at 30 min post-ligation, last at 24 h before sacrifice. Local bath BPC 157 (10 µg/kg) with assessed immediate normalization of portal hypertension was given immediately after establishing portal hypertension values at 4, 6, 8 week. BPC 157 therapy markedly abated jaundice, snout, ears, paws, and yellow abdominal tegmentum in controls since 4th week, ascites, nodular, steatotic liver with large dilatation of main bile duct, increased liver and/or cyst weight, decreased body weight. BPC 157 counteracts the piecemeal necrosis, focal lytic necrosis, apoptosis and focal inflammation, disturbed cell proliferation (Ki-67-staining), cytoskeletal structure in the hepatic stellate cell (α-SMA staining), collagen presentation (Mallory staining). Likewise, counteraction includes increased AST, ALT, GGT, ALP, total bilirubin, direct and indirect and decreased albumin serum levels. As the end-result appear normalized MDA- and NO-tissue values, next to Western blot of NOS2 and NOS3 in the liver tissue, and decreased IL-6, TNF-α, IL-1β levels in liver tissue. Finally, although portal hypertension is sustained in BDL-rats, with BPC 157 therapy, portal hypertension in BDL-rats is either not even developed or rapidly abated, depending on the given BPC 157's regimen. Thus, BPC 157 may counteract liver fibrosis and portal hypertension.

Pipe-3D: A Pipeline Based on Immunofluorescence, 3D Confocal Imaging, Reconstructions, and Morphometry for Biliary Network Analysis in Cholestasis

Cholestasis, the impairment of bile flux out of the liver, is a common complication of many pathological liver disorders, such as cholangiopathies, primary biliary sclerosis, and primary biliary cirrhosis. Besides accumulation of bile acids in the liver and blood, it leads to a proliferative response of the biliary tree termed as a ductular reaction. The ductular reaction is characterized by enhanced proliferation of cholangiocytes, which form the epithelial lining of bile ducts. This strong reaction of the biliary tree has been reported to generate a source of progenitor cells that can differentiate to hepatocytes or cholangiocytes during regeneration. On the other hand, it can cause periportal fibrosis eventually progressing to cirrhosis and death. In 2D histology, this leads to the appearance of an increased number of duct lumina per area of tissue. Yet, the biliary tree is a 3D vstructure and the appearance of lumina in thin slices may be explained by the appearance of novel ducts or by ramification or convolution of existing ducts in 3D. In many such aspects, traditional 2D histology on thin slices limits our understanding of the response of the biliary tree. A comprehensive understanding of architecture remodeling of the biliary network in cholestasis depends on robust 3D sample preparation and analysis methods. To that end, we describe pipe-3D, a processing and analysis pipeline visualization based on immunofluorescence, confocal imaging, surface reconstructions, and automated morphometry of the biliary network in 3D at subcellular resolution. This pipeline has been used to discover extensive remodeling of interlobular bile ducts in cholestasis, wherein elongation, branching, and looping create a dense ductular mesh around the portal vein branch. Surface reconstructions generated by Pipe-3D from confocal data also show an approximately fivefold enhancement of the luminal duct surface through corrugation of the epithelial lamina, which may increase bile reabsorption and alleviate cholestasis. The response of interlobular ducts in cholestasis was shown to be in sharp contrast to that of large bile ducts, de novo duct formation during embryogenesis. It is also distinct from ductular response in other models of hepatic injury such as choline-deficient, ethionine-supplemented diet, where parenchymal tissue invasion by ducts and their branches is observed. Pipe-3D is applicable to any model of liver injury, and optionally integrates tissue clearing techniques for 3D analysis of thick (>500 μm) tissue sections.

Biliary System Architecture: Experimental Models and Visualization Techniques

The complex architecture of the liver biliary network represents a structural prerequisite for the formation and secretion of bile as well as excretion of toxic substances through bile ducts. Disorders of the biliary tract affect a significant portion of the worldwide population, often leading to cholestatic liver diseases. Cholestatic liver disease is a condition that results from an impairment of bile formation or bile flow to the gallbladder and duodenum. Cholestasis leads to dramatic changes in biliary tree architecture, worsening liver disease and systemic illness. Recent studies show that the prevalence of cholestatic liver diseases is increasing. The availability of well characterized animal models, as well as development of visualization approaches constitutes a critical asset to develop novel pathogenetic concepts and new treatment strategies.

Adipose-derived mesenchymal stem cells slow disease progression of acute-on-chronic liver failure

A serious complication of chronic hepatic insufficiency is acute-on-chronic liver failure, a recognized syndrome characterized by acute decompensation of cirrhosis and organ/system failure. We investigated the use of adipose-derived mesenchymal stem cells (AD-MSCs) in an experimental model of acute-on-chronic liver failure, developed by microsurgical extrahepatic cholestasis in rats. Rats undergoing microsurgical extrahepatic cholestasis were treated by intraparenchymal liver injection of human or rat AD-MSCs, undifferentiated or previously differentiated in vitro toward the hepatocyte lineage. The groups treated with rat AD-MSCs showed less ascites, lower hepato- and splenomegaly, less testicular atrophy, and an improvement in serum biochemical hepatic parameters. There was also an improvement in histological liver changes, in which the area of fibrosis and bile duct proliferation were significantly decreased in the group treated with predifferentiated rat AD-MSCs. In conclusion, an isograft of hepatocyte-predifferentiated AD-MSCs injected intraparenchymally 2 weeks after microsurgery in extrahepatic cholestatic rats prevents secondary complications of acute-on-chronic hepatic failure. These data support the potential use of autologous AD-MSCs in the treatment of human cholestasis, and specifically of newborn biliary atresia, which could be beneficial for patients awaiting transplant.

Possible Involvement of Nitric Oxide in Enhanced Liver Injury and Fibrogenesis during Cholestasis in Cytoglobin-deficient Mice

This study clarified the role of Cygb, the fourth globin in mammals originally discovered in rat hepatic stellate cells (HSCs), in cholestatic liver disease. Bile duct ligation (BDL) augmented inflammatory reactions as revealed by increased infiltrating neutrophils, CD68⁺-macrophages, and chemokine expression in Cygb^-/- mice. In these mice, impairment of bile canalicular indicated by the loss of CD10 expression, down-regulation of bile salt transporters, increased total bile acid, and massive apoptotic and necrotic hepatocytes occurred with the release of cytochrome c, activation of caspase 3, resulting in reduced animal survival compared to wild-type mice. In Cygb^-/- mouse liver, all of NO metabolites and oxidative stress were increased. Treatment with NO inhibitor restrained all above phenotypes and restored CD10 expression in BDL Cygb^-/- mice, while administration of NO donor aggravated liver damage in BDL-wild type mice to the same extent of BDL-Cygb^-/- mice. N-acetylcysteine administration had a negligible effect in all groups. In mice of BDL for 1-3 weeks, expression of all fibrosis-related markers was significantly increased in Cygb^-/- mice compared with wild-type mice. Thus, Cygb deficiency in HSCs enhances hepatocyte damage and inflammation in early phase and fibrosis development in late phase in mice subjected to BDL, presumably via altered NO metabolism.

A label-retaining but unipotent cell population resides in biliary compartment of mammalian liver

Cells with slow proliferation kinetics that retain the nuclear label over long time periods-the label-retaining cells (LRCs)-represent multipotent stem cells in a number of adult tissues. Since the identity of liver LRCs (LLRCs) had remained elusive we utilized a genetic approach to reveal LLRCs in normal non-injured livers and characterized their regenerative properties in vivo and in culture. We found that LLRCs were located in biliary vessels and participated in the regeneration of biliary but not hepatocyte injury. In culture experiments the sorted LLRCs displayed an enhanced self-renewal capacity but a unipotent biliary differentiation potential. Transcriptome analysis revealed a unique set of tumorigenesis- and nervous system-related genes upregulated in LLRCs when compared to non-LRC cholangiocytes. We conclude that the LLRCs established during the normal morphogenesis of the liver do not represent a multipotent primitive somatic stem cell population but act as unipotent biliary progenitor cells.

N-acetyl-l-cysteine Prevents Bile Duct Ligation Induced Renal Injury by Modulating Oxidative Stress

The aim of the present study was to evaluate the effect of N-acetyl-l-cysteine (NAC) on bile duct ligation (BDL) induced oxidative stress in kidneys. Male Wistar rats were randomly segregated into four groups; sham control (SC), SC + NAC, BDL and BDL + NAC group. Liver damage was induced following BDL and renal injury was assessed by kidney function tests along with lipid peroxidation, nitrite levels, thiols and antioxidant enzymes. Three weeks after BDL, rats developed renal dysfunction in terms of elevated serum creatinine levels. BDL animals exhibited an increase in lipid peroxidation, reduction in thiols and redox ratio in liver and kidney tissue along with altered antioxidant enzymes in kidneys. BDL animals that were orally administered NAC at a daily dose 100 mg/kg for duration of two weeks, showed significant reduction in serum creatinine levels. NAC was effective in lowering lipid peroxidation and was able to restore thiol levels along with GSH/GSSG ratio in both liver and kidneys along with the activity of antioxidant enzymes in the kidneys of BDL animals. The results clearly demonstrate the efficacy of NAC in attenuating oxidative stress in kidneys, suggesting a therapeutic role for NAC in individuals with renal dysfunction following BDL.

Nesfatin-1 alleviates extrahepatic cholestatic damage of liver in rats

Obstructive jaundice (OJ) can be defined as cessation of bile flow into the small intestine due to benign or malignant changes. Nesfatin-1, recently discovered anorexigenic peptide derived from nucleobindin-2 in hypothalamic nuclei, was shown to have anti-inflammatory and antiapoptotic effects. This study is aimed to investigate the therapeutic effects of nesfatin-1 on OJ in rats. Twenty-four adult male Wistar-Hannover rats were randomly assigned to three groups: sham (n = 8), control (n = 8), and nesfatin (n = 8). After bile duct ligation, the study groups were treated with saline or nesfatin-1, for 10 days. Afterward, blood and liver tissue samples were obtained for biochemical analyses, measurement of cytokines, determination of the oxidative DNA damage, DNA fragmentation, and histopathologic analyses. Alanine aminotransferase and gamma-glutamyl transferase levels were decreased after the nesfatin treatment; however, these drops were statistically non-significant compared to control group (p = 0.345, p = 0.114). Malondialdehyde levels decreased significantly in nesfatin group compared to control group (p = 0.032). Decreases in interleukin-6 and tumor necrosis factor-α levels from the liver tissue samples were not statistically significant in nesfatin group compared to control group. The level of oxidative DNA damage was lower in nesfatin group, however this result was not statistically significant (p = 0.75). DNA fragmentation results of all groups were similar. Histopathological examination revealed that there was less neutrophil infiltration, edema, bile duct proliferation, hepatocyte necrosis, basement membrane damage, and parenchymal necrosis in nesfatin compared to control group. The nesfatin-1 treatment could alleviate cholestatic liver damage caused by OJ due to its anti-inflammatory and antioxidant effects.

Decompensated liver cirrhosis and neural regulation of mesenteric vascular tone in rats: role of sympathetic, nitrergic and sensory innervations

We evaluated the possible alterations produced by liver cholestasis (LC), a model of decompensated liver cirrhosis in sympathetic, sensory and nitrergic nerve function in rat superior mesenteric arteries (SMA). The vasoconstrictor response to electrical field stimulation (EFS) was greater in LC animals. Alpha-adrenoceptor antagonist phentolamine and P2 purinoceptor antagonist suramin decreased this response in LC animals more than in control animals. Both non-specific nitric oxide synthase (NOS) L-NAME and calcitonin gene related peptide (CGRP) (8-37) increased the vasoconstrictor response to EFS more strongly in LC than in control segments. Vasomotor responses to noradrenaline (NA) or CGRP were greater in LC segments, while NO analogue DEA-NO induced a similar vasodilation in both experimental groups. The release of NA was not modified, while those of ATP, nitrite and CGRP were increased in segments from LC. Alpha 1 adrenoceptor, Rho kinase (ROCK) 1 and 2 and total myosin phosphatase (MYPT) expressions were not modified, while alpha 2B adrenoceptor, nNOS expression and nNOS and MYPT phosphorylation were increased by LC. Together, these alterations might counteract the increased splanchnic vasodilation observed in the last phases of decompensated liver cirrhosis.

Induction of experimental obstructive cholestasis in mice

The induction of experimental obstructive cholestasis is a reliable model for cholestatic liver diseases in rodents. Bile duct ligation (BDL) in mice provokes typical time-dependent morphological and structural changes in the liver, ranging from liver cell injury and elevated serum enzyme levels after several days, to a severe inflammatory response in the liver after 5-7 days, up to an advanced hepatic fibrosis as soon as three to four weeks after surgical ligation of the common biliary duct. Upon BDL induction, hepatic stellate cells become activated and transdifferentiate into myofibroblasts that produce extracellular matrix proteins such as collagen. In principle, the periportal fibrosis induced by BDL in rat livers is reversible. After the relief of a biliary obstruction, the liver has the capacity to revert to a nearly normal histological architecture and a fully normal biochemical function. When BDL surgery is performed by an experienced scientist, this model has very high reproducibility among all fibrotic models. All these factors corroborate the outstanding value of this model for basic and translational research in biomedicine and hepatology. Nevertheless, this model can result in significant variations when surgery is carried out by untrained personnel or when unconscious modifications are implemented that affect the quality of the intervention. A detailed protocol is provided here for the provision of reliable and reproducible BDL in mice.

Human Progenitor Cell Quantification after Xenotransplantation in Rat and Mouse Models by a Sensitive qPCR Assay

Xenotransplantation of human cells in animal models is an essential tool for evaluation of safety and efficacy of cell-based products for therapeutic use. Sensitive and reproducible methods are needed to detect and quantify human cells engrafted into the host tissue either in the targeted organ or in undesired locations. We developed a robust quantitative polymerase chain reaction (qPCR) assay based on amplification of human AluYb8 repeats, to assess the number of human cells present in rat or mouse tissues after transplantation. Standard curves of mixed human/rodent DNA and mixed human/rodent cells have been performed to determine the limit of detection and linear range of the assay. Standard curves from DNA mixing differed significantly from standard curves from cell mixing. We show here that the AluYb8 qPCR assay is highly reproducible and is able to quantify human cells in a rodent cell matrix over a large linear range that extends from 50% to 0.01% human cells. Short-term in vivo studies showed that human cells could be quantified in mouse liver up to 7 days after intrasplenic transplantation and in rat liver 4 h after intrahepatic transplantation.

The Effect of Montelukast on Liver Damage in an Experimental Obstructive Jaundice Model

Background

Montelukast is a cysteinyl-leukotriene type 1 (CysLT₁) selective receptor antagonist. In recent years, investigations have shown that montelukast possesses secondary anti-inflammatory activities and also antioxidant effects. For this reason, we aimed to determine the possible effects of montelukast on liver damage in experimental obstructive jaundice.

Methods

30 Wistar-Albino male rats were randomized and divided into three groups of 10 animals each: group I, sham-operated; group II, ligation and division of the common bile duct (BDL) followed by daily intraperitoneal injection of 1 ml of saline; group III, BDL followed by daily intraperitoneal injection of 10 mg/kg montelukast dissolved in saline. The animals were killed on postoperative day 7 by high-dose diethyl ether inhalation. Blood and liver samples were taken for examination.

Results

In this study, liver malondialdehyde (MDA) (p = 0.001), myeloperoxidase (p = 0.003), and total sulfhydryl (SH) (p = 0.009) were found to be significantly different between the BDL + montelukast and the BDL groups. Plasma total SH (p = 0.002) and MDA (p = 0.027) values were also statistically different between these groups. Statistical analyses of histological activity index scores showed that the histopathological damage in the BDL + montelukast group was significantly less than the damage in the control group (p < 0.05 for all pathological parameters).

Conclusion

According to the results of this study, montelukast showed a significant hepatoprotective effect in this experimental obstructive jaundice model, which might be due to its antioxidant and anti-inflammatory activities.

Bile duct ligation in mice: induction of inflammatory liver injury and fibrosis by obstructive cholestasis

In most vertebrates, the liver produces bile that is necessary to emulsify absorbed fats and enable the digestion of lipids in the small intestine as well as to excrete bilirubin and other metabolic products. In the liver, the experimental obstruction of the extrahepatic biliary system initiates a complex cascade of pathological events that leads to cholestasis and inflammation resulting in a strong fibrotic reaction originating from the periportal fields. Therefore, surgical ligation of the common bile duct has become the most commonly used model to induce obstructive cholestatic injury in rodents and to study the molecular and cellular events that underlie these pathophysiological mechanisms induced by inappropriate bile flow. In recent years, different surgical techniques have been described that either allow reconnection or reanastomosis after bile duct ligation (BDL), e.g., partial BDL, or other microsurgical methods for specific research questions. However, the most frequently used model is the complete obstruction of the common bile duct that induces a strong fibrotic response after 21 to 28 days. The mortality rate can be high due to infectious complications or technical inaccuracies. Here we provide a detailed surgical procedure for the BDL model in mice that induce a highly reproducible fibrotic response in accordance to the 3R rule for animal welfare postulated by Russel and Burch in 1959.

Lobe-specific heterogeneity in asymmetric dimethylarginine and matrix metalloproteinase levels in a rat model of obstructive cholestasis

We investigated the effects of obstructive cholestasis in different hepatic lobes by evaluating asymmetric dimethylarginine (ADMA) (a nitric oxide synthase inhibitor), protein methyltransferase (PRMT) and dimethylarginine dimethylaminohydrolase (DDAH) (enzymes involved, resp., in its synthesis and degradation), the cationic transporter (CAT), and metalloproteinase (MMP) activity. Sixteen male Wistar rats underwent a 3-day cholestasis by common bile duct ligation (BDL) or sham operation. Blood samples and hepatic biopsies from left lobe (LL), median lobe (ML), and right lobe (RL) were collected. Serum hepatic enzymes, tissue ADMA, DDAH activity, CAT-2 protein, mRNA expression of DDAH and PRMT, and MMP-2 and MMP-9 activity were monitored. Cholestasis was confirmed by altered serum hepatic enzymes. Higher levels of tissue ADMA were detected in RL and ML as compared with LL. PRMT mRNA expression and DDAH activity did not differ among the lobes after BDL. CAT-2 levels are higher in the RL and ML in the sham-operated group. Higher activity in MMP-2 and MMP-9 was found in RL. In conclusion, after cholestasis an increase in hepatic ADMA in RL and ML was detected as well as tissue MMP-2 and MMP-9 activation in RL, supporting the evidence of functional heterogeneity among the liver lobes also occurring in an obstructive cholestasis model.

The benefits of hypothermic machine perfusion are enhanced with Vasosol and α-tocopherol in rodent donation after cardiac death livers

The use of hypothermic machine perfusion (HMP) has recently been used to show an improvement in both standard and extended criteria donor liver grafts but creating a more dynamic preservation environment that can be supplemented with a variety of additives to aid in cold temperature metabolism and vasodilatation. Increasing the benefits of HMP, we explore the use of α-tocopherol in reducing inflammatory markers and apoptotic pathways to reduce the incidence of preservation injury. We explored the use of a donation after cardiac death (DCD) rodent model to test the additive benefits of α-tocopherol in HMP. The addition of α-tocopherol reduced the level of alanine aminotransferase (ALT) over the course of reperfusion as well, reduced the levels of inflammatory cytokines within a 90 minute reperfusion biopsy. Further benefit was seen with α-tocopherol through the reduction of the level of caspase 3/7 in the circulation, shown to be a result of the reduction of the levels of Cytochrome C mRNA. Liver perfusion with Vasosol® and HMP could benefit further from the addition of α-tocopherol to existing formulations of Vasosol®.

Chronic cholestatic liver diseases: clues from histopathology for pathogenesis

Chronic cholestatic liver diseases include fibrosing cholangiopathies such as primary biliary cirrhosis or primary sclerosing cholangitis. These and related cholangiopathies clearly display pathologies associated with (auto)immunologic processes. As the cholangiocyte's apical membrane is exposed to the toxic actions of the bile fluid, the interaction of bile with cholangiocytes and the biliary tree in general must be considered to completely understand the pathogenesis of cholangiopathies. While the molecular processes involved in the hepatocellular formation of bile are well understood in both normal and pathophysiologic conditions, those in the bile ducts of normal liver and in livers with cholangiopathies lag behind. This survey highlights key mechanisms known to date that are important for the formation of bile by hepatocytes and its modification by the biliary tree. It also delineates the clinical pathophysiologic findings for cholangiopathies and puts them in perspective with current experimental models to reveal the pathogenesis of cholangiopathies and develop novel therapeutic approaches.

CGX, a multiple herbal drug, improves cholestatic liver fibrosis in a bile duct ligation-induced rat model

ETHNOPHARMACOLOGIC RELEVANCE

CGX is a modification of a traditional herbal medicine that has been used for various liver disorders as a meaning of "cleaning the liver". The cholestatic liver disorders become prevalent. BACK GROUND AND AIM: This study aimed to investigate the anti-hepatic fibrosis effects of CGX and its underlying mechanisms in a rat model of bile duct ligation (BDL).

MATERIALS AND METHODS

BDL was conducted in SD rats except shame operation group. The rats were orally administrated with distilled water, CGX (25 or 50 mg/kg) or ursodeoxycholic acid (UDCA, 25 mg/kg) for two weeks. The pharmaceutical effects and mechanisms were analyzed in histopathology, biochemistry, oxidative stress/antioxidant biomarkers and hepatic fibrogenic cytokines levels.

RESULTS

BDL markedly elevated white blood cell (WBC) counts as well as changed subset proportions such as increased neutrophils and decreased lymphocytes in peripheral blood. BDL drastically elevated the serum levels of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total bilirubin, and hepatic tissue levels of hydroxyproline and malondialdehyde (MDA), while it reduced the total glutathione (GSH) content and the activities of GSH-redox system enzymes such as GSH-peroxidase, GSH-reductase and GSH-S-transferase. These alterations were significantly attenuated by CGX treatment (mainly 50 mg/kg). CGX treatment normalized both the accumulation of collagen in hepatic tissue and the increased levels of profibrogenic cytokine including transforming growth factor-β1 (TGF-β1) and platelet-derived growth factor-BB (PDGF-BB). Moreover, CGX treatment enhanced interferon-gamma (IFN-γ) expression compare to the BDL group at the protein and gene level.

CONCLUSION

These results suggest that CGX exerts anti-hepatofibrotic effect in rat BDL model, and the responsible mechanisms involve the inhibition of hepatic fibrogenic cytokines and oxidative stress.

The wound-healing response and upregulated embryonic mechanisms: brothers-in-arms forever

The cutaneous wound-healing reaction occurs in overlapping but inter-related phases, which ultimately result in fibrosis. The pathophysiological mechanisms involved in fibrotic diseases, including organ-related and even systemic diseases, such as systemic sclerosis, could represent the successive systemic upregulation of extraembryonic-like phenotypes, that is, amniotic and vitelline phenotypes. These two extraembryonic-like phenotypes act on the injured tissue to induce a process similar to gastrulation, which occurs during the early phases of embryo development. The amniotic-like phenotype plays a leading role in the development of neurogenic responses with significant hydroelectrolytic alterations that essentially represent the development of open microcirculation within the injured tissue. In turn, through the overlapping expression of a vitelline-like phenotype, a bone marrow-related response is produced. Interstitial infiltration by molecular and cellular mediators contributed by amniotic- and vitelline-like functions provides the functional and metabolic autonomy needed for inducing new tissue formation through mechanisms similar to those that act in gastrulation during the early phases of embryonic development. Thus, while a new tissue is formed, it quickly evolves into fibrotic tissue because of premature senescence. Mechanisms related to extraembryonic-like functions have been suggested in the following physiological and pathological processes: embryonic development; wound-healing reactions occurring during adult life; and senescence. The existence of this sort of basic self-organizing fractal-like functional pattern is an essential characteristic of our way of life.

[Remote ischemic conditioning: short-term effects on rat liver ischemic-reperfusion injury]

INTRODUCTION

Several techniques have been developed to reduce ischemic-reperfusion injury. A novel method is the remote ischemic perconditioning, applied parallel with target organ ischemia.

AIM

The aim of the study was to determine the extent of liver ischemic-reperfusion injury via the application of this novel method.

METHODS

Male Wistar rats (n = 30, 10/group) were subjected to 60-minute partial liver ischemia and 60-minute reperfusion. Rats in the perconditioned group received conditioning treatment during the last 40 minutes of liver ischemia by infrarenal aortic clamping. Hepatic and lower limb microcirculation was monitored by laser Doppler flowmeter during reperfusion. After reperfusion, liver samples were taken for routine histological examination and redox-state assessment. Serum transaminase activities and liver tissue heat-shock protein-72 expression were measured.

RESULTS

Parameters of microcirculation showed significant (p<0.05) improvement in the perconditioned group in comparison with the control. Besides the significant improvement observed in the serum alanine amino-transferase activities, significantly milder tissue injury was detected histologically in the liver sections of the perconditioned group. Moreover, significant improvement was found in the redox-state parameters.

CONCLUSION

Perconditioning may be a reasonable possibility to reduce liver ischemic-reperfusion injury.

A half century (1961-2011) of applying microsurgery to experimental liver research

The development of microsurgery has been dependent on experimental animals. Microsurgery could be a very valuable technique to improve experimental models of liver diseases. Microdissection and microsutures are the two main microsurgical techniques that can be considered for classifying the experimental models developed for liver research in the rat. Partial portal vein ligation, extrahepatic cholestasis and hepatectomies are all models based on microdissection. On the other hand, in portacaval shunts, orthotopic liver transplantation and partial heterotopic liver transplantation, the microsuture techniques stand out. By reducing surgical complications, these microsurgical techniques allow for improving the resulting experimental models. If good experimental models for liver research are successfully developed, the results obtained from their study might be particularly useful in patients with liver disease. Therefore experimental liver microsurgery could be an invaluable way to translate laboratory data on liver research into new clinical diagnostic and therapeutic strategies.

Aqueous extract of Artemisia iwayomogi Kitamura attenuates cholestatic liver fibrosis in a rat model of bile duct ligation

Cholestatic liver fibrosis, characterized by excessive accumulation of extracellular matrix (ECM) proteins, is associated with bile acid-induced oxidative stress and lipid peroxidation. We evaluated the therapeutic or protective effect of an aqueous extract of Artemisia iwayomogi Kitamura (WAI) in a rat bile duct ligation (BDL)-induced hepatic fibrogenesis model. After BDL, rats were treated once daily with 25 or 50 mg/kg of WAI for 2weeks. The serum bilirubin, aspartate transaminase, alanine transaminase, malondialdehyde, and liver hydroxyproline levels were drastically increased in the BDL group. WAI administration significantly reduced these markers and restored BDL-induced depletion of glutathione content and glutathione peroxidase activity. Cholestatic liver injury and collagen deposition were markedly attenuated by WAI treatment, and these changes were paralleled by significantly suppressed gene and protein expression of fibrogenic factors, including hepatic alphasmooth muscle actin, platelet-derived growth factor, and transforming growth factor β. Our data suggest that WAI may have antifibrotic properties via both improvement of antioxidant activities and inhibition of ECM protein production in the rat model of BDL.

Liver impairment after portacaval shunt in the rat: the loss of protective role of mast cells?

Mast cells are involved in various liver diseases and appear to play a broader pathogenic role than originally thought. They may participate in the splanchnic alterations related to a porto-systemic shunt. To verify this hypothesis we studied the serum and hepatic histological changes in rats four weeks after an end-to-side portacaval shunt. In this experimental model of chronic liver insufficiency we also assessed the mucosal mast cells (MMC) and connective tissue mast cells (CTMC) in the liver, mesenteric lymph nodes and small intestine, as well as the serum levels of rat mast cell protease-II (RMCP-II). The results show liver and testes atrophy, with hypoalbuminemia (p=0.0001), hyperbilirubinemia (p=0.0001) and increase in aspartate aminotransferase (p=0.004) and alanine aminotransferase (p=0.0001). Hepatic histopathology demonstrates hepatocytic necrosis and apoptosis, portal inflammation, biliary proliferation, steatosis and fibrosis. There is a decrease of MMCs and CTMCs in the liver, while in the ileum CTMCs increase and MMCs decrease. These results suggest the involvement of mast cells in the pathophysiological splanchnic impairments in this experimental model. In particular, the decreased number of liver mast cells may be associated with the hepatic atrophy. If this is the case, we propose that the disruption of the hepato-intestinal axis after a portocaval shunt in the rat could inhibit the ability of the liver to developing an appropriate repair response mediated by mast cells.

Portal hypertensive cardiovascular pathology: the rescue of ancestral survival mechanisms?

The portal system derives from the vitelline system, which is an extra-embryonic venous system. It could be suggested that this extraembryonic origin determines some of the characteristics attributed to portal hypertension, both compensated, i.e. prehepatic, and decompensated, i.e. fibrotic or cirrhotic. The experimental models most frequently used for studying both types of portal hypertension are portal vein ligation and common bile duct ligation in rats, respectively. We propose that in partial portal vein ligated rats, a low-grade inflammatory response, formed by the successive expression of three overlapping phenotypes - ischemia-reperfusion, vitellogenic-like and remodeling or gastrulation-like - is produced. The names of these inflammatory phenotypes developed in compensated portal hypertension are based on some metabolic similarities that can be established with the abovementioned phases of embryonic development. In bile-duct ligated rats, decompensation related to hepatic insufficiency would induce a high-grade inflammatory response. In this experimental model, the splanchnic interstitium, the mesenteric lymph and the peritoneal mesothelium seem to create an inflammatory axis that produces ascites. The functional comparison between the ascitic and the amniotic fluids would imply that, in the decompensated portal hypertensive syndrome, the abdominal mesothelium acquires properties of the amniotic membranes or amnion. In conclusion, the hypothetical comparison between the inflammatory portal hypertensive evolutive types and the evolutive phases of embryonic development could allow for translational research.

Will we ever model PSC? - "it's hard to be a PSC model!"

Cholangiopathies such as primary sclerosing cholangitis (PSC) represent an important group of liver diseases of the intra- and extrahepatic bile ducts frequently causing end-stage liver disease with significant morbidity and mortality due to limited treatment options. The relatively low incidence of PSC and the difficult accessibility of the human bile duct system for longitudinal studies may represent some of the critical reasons for the lack of profound knowledge in regard to PSC pathophysiology. Therefore, there is an urgent need for reliable, well-defined and easily reproducible animal models to learn more about the pathophysiology of PSC and to test novel treatment modalities. In an ideal world, immunogenetically predisposed animals would develop fibrous-obliterative cholangitis of the intra- and extrahepatic bile ducts in association with inflammation of the gut (especially colitis) in a highly reproducible manner allowing to test new drugs. To date, however, no such animal model is available. We aimed to provide a systematic overview of current available rodent models for sclerosing cholangitis and biliary fibrosis and therefore critically analyzed the characteristics of models for chemically-induced cholangitis, knock-out mouse models with cholangitis, cholangitis induced by infectious agents, models of experimental biliary obstruction, models involving enteric bacterial cell-wall components or colitis, and models of primary biliary epithelial and endothelial cell injury.

The interstitial lymphatic peritoneal mesothelium axis in portal hypertensive ascites: when in danger, go back to the sea

Portal hypertension induces a splanchnic and systemic low-grade inflammatory response that could induce the expression of three phenotypes, named ischemia-reperfusion, leukocytic, and angiogenic phenotypes.During the splanchnic expression of these phenotypes, interstitial edema, increased lymph flow, and lymphangiogenesis are produced in the gastrointestinal tract. Associated liver disease increases intestinal bacterial translocation, splanchnic lymph flow, and induces ascites and hepatorenal syndrome. Extrahepatic cholestasis in the rat allows to study the worsening of the portal hypertensive syndrome when associated with chronic liver disease. The splanchnic interstitium, the mesenteric lymphatics, and the peritoneal mesothelium seem to create an inflammatory pathway that could have a key pathophysiological relevance in the production of the portal hypertension syndrome complications. The hypothetical comparison between the ascitic and the amniotic fluids allows for translational investigation. From a phylogenetic point of view, the ancestral mechanisms for amniotic fluid production were essential for animal survival out of the aquatic environment. However, their hypothetical appearance in the cirrhotic patient is considered pathological since ultimately they lead to ascites development. But, the adult human being would take advantage of the potential beneficial effects of this “amniotic-like fluid” to manage the interstitial fluids without adverse effects when chronic liver disease aggravates.

Amniotic membrane application reduces liver fibrosis in a bile duct ligation rat model

Biliary fibrosis and resultant cirrhosis are among the most common outcomes of chronic liver diseases. Currently, liver transplantation remains the only effective treatment. In seeking alternative therapeutic approaches, we focused on the potential use of the human amniotic membrane (AM). Indeed, AM has gained increasing importance for its antiscarring, anti-inflammatory, and wound-healing properties, as well as for the multipotent differentiation ability and immunomodulatory features of AM-derived cells. Intriguingly, we have recently demonstrated that placenta-derived cells reduce lung fibrosis in bleomycin-treated mice, and that AM patches reduce postischemic cardiac injury in rats. Hence, we have now investigated the effects of human AM on biliary fibrosis induced in rats through the bile duct ligation (BDL) procedure. A fragment of human AM was applied onto the liver surface after BDL and the effects on fibrosis establishment and progression were evaluated at different time points in comparison with fibrosis progression in control BDL rats. The degree of liver fibrosis was first assessed by the semiquantitative Knodell scoring system and, thereafter, by digital image morphometric analysis to quantify the area occupied by ductular reaction, activated myofibroblasts, and collagen deposition. We demonstrated a significant reduction in the severity of BDL-induced fibrosis in AM-treated rats. Indeed, while fibrosis progressed rapidly in control BDL rats, leading to cirrhosis within 6 weeks, AM-treated rats showed confined fibrosis at the portal/periportal area with no signs of cirrhosis, and a reduction in collagen deposition to about 50% of levels observed in control BDL rats. In addition, the AM was able to significantly slow the gradual progression of the ductular reaction and reduce, at all time points, the area occupied by activated myofibroblasts. These findings suggest that human AM, when applied as a patch onto the liver surface, might inhibit fibrosis progression in BDL-injured livers, and could protect against hepatic damage associated with fibrotic degeneration.

Involvement of cholangiocyte proliferation in biliary fibrosis

Cholangiocytes are the epithelial cells that line the biliary tree. In the adult liver, they are a mitotically dormant cell population, unless ductular reaction is triggered by injury. The ability of cholangiocytes to proliferate is important in many different human pathological liver conditions that target this cell type, which are termed cholangiopathies (i.e. primary biliary cirrhosis, primary sclerosing cholangitis and biliary atresia). In our article, we provide background information on the morphological and functional heterogeneity of cholangiocytes, summarize what is currently known about their proliferative processes, and briefly describe the diseases that target these cells. In addition, we address recent findings that suggest cholangiocyte involvement in epithelial-to-mesenchymal transformation and liver fibrosis, and propose directions for future studies.

Bile duct ligation: step-by-step to cholangiocyte inflammatory tumorigenesis

Chronic liver inflammation after murine bile duct ligation could evolve according to three interrelated phenotypes, which would have different metabolic, functional and histologic characteristics. Liver injury secondary to extrahepatic cholestasis would induce an early ischemic-reperfusion phenotype with cholangiocyte depolarization, abnormal ion transport, hypometabolism with anaerobic glycolysis and hepatocytic apoptosis. This phenotype, in turn, could trigger the switch to a leukocytic phenotype by the cholangiocytes, with an intense anaplerotic activity, hypermetabolism, extracellular matrix degradation and moderated proliferation to create a pseudotissue with metabolic autonomy and paracrine functions. In the long-term cholestasis-drive tumorigenesis, the tumorous tissue would principally consist of cholangiocyte parenchyma, with an impressive biosynthetic activity through the tricarboxylic cell cycle. In terms of the tumorous stroma, made up by fibroplasia and angiogenesis, it would favor the tumor trophism. In conclusion, the great intensity and persistence in the expression of these phenotypes by the cholestatic cholangiocyte would favor chronic inflammatory tumorigenesis.

Splanchnic Th(2) and Th(1) cytokine redistribution in microsurgical cholestatic rats

BACKGROUND

Long-term extrahepatic cholestasis in the rat induces ductular proliferation and fibrosis in the liver, portal hypertension, splenomegaly, portosystemic collateral circulation, and ascites. These splanchnic alterations could have an inflammatory pathophysiology.

MATERIAL AND METHODS

We measured serum levels of hepatobiliary injury markers and the acute phase proteins, alpha-1-major acid protein (alpha(1)-MAP) and alpha-1-acid glycoprotein (alpha(1)-GPA) in rats 6 wk after microsurgical extrahepatic cholestasis. We also assayed Th(1) (TNF-alpha and IL-1beta) and Th(2) (IL-4 and IL-10) cytokine levels in the liver, ileum, spleen, and mesenteric lymph complex by enzyme-linked immunosorbent assay (ELISA) techniques. Liver fibrosis was measured by Sirius red stain and by using an image system computer-assisted method and mast cell liver infiltration by Giemsa stain.

RESULTS

The cholestatic rats showed an increase (P<0.001) in serum levels of bile acids, total and direct bilirubin, AST, ALT, AST/ALT index, gamma-GT, alkaline phosphatase, alpha(1)- MAP, alpha(1)-GPA, and LDH (P<0.05) in relation to sham-operated rats. TNF-alpha, IL-1beta, IL-4, and IL-10 increased in the ileum (P<0.01) and mesenteric lymph complex (P<0.001), and decreased in the liver (P<0.001). A marked bile proliferation associated with fibrosis (P<0.001) and mast cell infiltration was also shown in the liver of cholestatic rats.

CONCLUSION

The splanchnic redistribution of cytokines, with an increase of Th(1) and Th(2) production in the small bowel and in the mesenteric lymph complex, supports the key role of inflammatory mechanisms in rats with secondary biliary fibrosis.

The value of microsurgery in liver research

The use of an operating microscope in rat liver surgery makes it possible to obtain new experimental models and improve the already existing macrosurgical models. Thus, microsurgery could be a very valuable technique to improve experimental models of hepatic insufficiency. In the current review, we present the microsurgical techniques most frequently used in the rat, such as the portacaval shunt, the extrahepatic biliary tract resection, partial and total hepatectomies and heterotopic and orthotopic liver transplantation. Hence, reducing surgical complications allows for perfecting the resulting experimental models. Thus, liver atrophy related to portacaval shunt, prehepatic portal hypertension secondary to partial portal vein ligation, cholestasis by resection of the extrahepatic biliary tract, hepatic regeneration after partial hepatectomies, acute liver failure associated with subtotal or total hepatectomy and finally complications derived from preservation or rejection in orthotopic and heterotopic liver transplantation can be studied in more standardized experimental models. The results obtained are therefore more reliable and facilitates the flow of knowledge from the bench to the bedside. Some of these microsurgical techniques, because of their simplicity, can be performed by researchers without any prior surgical training. Other more complex microsurgical techniques require in-depth surgical training. These techniques are ideal for achieving a complete surgical training and more select microsurgical models for hepatology research.