Chronic hepatitis in dogs: a review of current understanding of the aetiology, progression, and treatment

Human placental hydrolysate promotes the long-term culture of hepatocyte-like cells derived from canine bone marrow

Long-term culture of canine artificial hepatocytes has not been established. We hypothesized that human placental hydrolysate (hPH) may support the long-term culture of differentiated hepatocyte-like cells. Canine bone marrow cells were cultured using modified hepatocyte growth medium supplemented with hPH. Quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical analysis for albumin, qualitative RT-PCR for cytochrome P450 1A1 (CYP1A1), hepatocyte growth factor (HGF), Cytokeratin 7 (CK7), CD90, CD44, and CD34, and functional analyses of CYP450 activity and low-density lipoprotein (LDL) uptake were performed. Cultured hepatocyte-like cells were able to maintain hepatocyte characteristics, including morphology, albumin synthesis, CYP450 activity, and LDL uptake for 80 days. Thus, hPH may be a potential facilitator for the long-term culture of hepatocyte-like cells. Clinicopathologically, this culture protocol of artificial hepatocytes will contribute to liver function evaluation.

Conversion of mesenchymal stem cells into a canine hepatocyte-like cells by Foxa1 and Hnf4a

Introduction

Hepatocytes, which account for the majority of liver tissue, are derived from the endoderm and become hepatocytes via differentiation of hepatic progenitor cells. Induced hepatocyte-like (iHep) cells and artificial liver tissues are expected to become useful, efficient therapies for severe and refractory liver diseases and to contribute to drug discovery research. The establishment of iHep cell lines are needed to carry out liver transplants and assess liver toxicity in the rising number of dogs affected by liver disease. Recently, direct conversion of non-hepatocyte cells into iHep cells was achieved by transfecting mouse adult fibroblasts with the Forkhead box protein A1 (Foxa1) and hepatocyte nuclear factor 4 homeobox alpha (Hnf4α) genes. Here, we applied this conversion process for the differentiation of canine bone marrow stem cells (cBMSCs) into hepatocyte-like cells.

Methods

Bone marrow specimens were collected from four healthy Beagle dogs and used to culture cBMSCs in Dulbecco's Modified Eagle's Medium (DMEM). The cBMSCs displayed the following characteristic features: plastic adherence; differentiation into adipocytes, osteoblasts and chondrocytes; and a cell surface antigen profile of CD29 (+), CD44 (+), CD90 (+), CD45 (−), CD34 (−) and CD14 (−), or CD11b (−) and CD79a (−), or CD19 (−) and HLA class II(−). The cBMSCs were seeded in a collagen I-coated plate and cultured in DMEM with 10% fetal bovine serum and transfected with retroviruses expressing Foxa1 and Hnf4α the following day. Canine iHep cells were differentiated from cBMSCs in culture on day 10, and were analyzed for morphology, RNA expression, immunocytochemistry, urea production, and low-density lipoprotein (LDL) metabolism.

Results

The cBMSCs expressed CD29 (98.06 ± 1.14%), CD44 (99.59 ± 0.27%) and CD90 (92.78 ± 4.89%), but did not express CD14 (0.47 ± 0.29%), CD19 (0.44 ± 0.39%), CD34 (0.33 ± 0.25%), CD45 (0.46 ± 0.34%) or MHC class II (0.54 ± 0.40%). The iHep cells exhibited morphology that included circular to equilateral circular shapes, and the formation of colonies that adhered to each other 10 days after Foxa1 and Hnf4α transfection. Quantitative RT-PCR analysis showed that the expression levels of the genes encoding albumin (ALB) and cadherin (CDH) in iHep cells on day 10 were increased approximately 100- and 10,000-fold, respectively, compared with cBMSCs. Corresponding protein expression of ALB and epithelial-CDH was confirmed by immunocytochemistry. Important hepatic functions, including LDL metabolic ability and urea production, were increased in iHep cells on day 10.

Conclusion

We successfully induced cBMSCs to differentiate into functional iHep cells. To our knowledge, this is the first report of canine liver tissue differentiation using Foxa1 and Hnf4α gene transfection. Canine iHep cells are expected to provide insights for the construction of liver models for drug discovery research and may serve as potential therapeutics for canine liver disease.

Hepatocyte expression and prognostic importance of senescence marker p21 in liver histopathology samples from dogs with chronic hepatitis

BACKGROUND

Chronic hepatitis (CH) occurs commonly in dogs but is associated with a variable and largely unpredictable prognosis. p21, a cell-cycle inhibitor and marker of cellular senescence, is upregulated in human liver disease and is a better prognostic marker than histological or clinical scoring systems.

OBJECTIVE

To quantify hepatocyte p21 immunopositivity in histopathology samples from dogs with CH and determine its association with outcome.

ANIMALS

Twenty-six client-owned dogs with histologically confirmed CH, and 15 dogs with normal liver histology.

METHODS

Medical records and liver histopathology samples were retrospectively reviewed to identify cases of CH. Immunohistochemistry for p21 was performed on all samples and hepatocyte immunopositivity was visually quantified. Relationships between p21 and dog age and dog survival time were statistically evaluated.

RESULTS

Hepatocyte p21 immunopositivity in dogs with CH was high (median percentage of positive hepatocytes: 90%, range: 20%-98%) and exceeded 70% in 23/26 cases with no association with age. In control dogs, p21 immunopositivity was low (≤15% positive hepatocytes in 12/15 cases) and was positively correlated with age (rs  = 0.63; P = .011). Dogs with p21 immunopositivity exceeding 91.8% (upper tercile) had significantly shorter survival compared to dogs with less than 88.9% immunopositivity (lowest tercile; 218 versus 874 days, P = .006). Increasing hepatocyte p21 immunopositivity was significantly negatively associated with survival time (HR 4.12; 95% CI 1.34-12.63; P = .013).

CONCLUSIONS AND CLINICAL IMPORTANCE

Marked p21 immunopositivity in dogs with CH might be indicative of widespread hepatocellular senescence. A significant association with survival time also suggests a potential value for p21 quantification in determining prognosis.

Cardiac-gated, phase contrast magnetic resonance angiography is a reliable and reproducible technique for quantifying blood flow in canine major cranial abdominal vessels

Blood flow changes in cranial abdominal vessels are important contributing factors for canine hepatic disease. This prospective, experimental, pilot study aimed to evaluate cardiac-gated, phase contrast magnetic resonance angiography (PCMRA) as a method for characterizing blood flow in canine major cranial abdominal vessels. Eleven, healthy, adult beagle dogs were sampled. Cardiac-gated, phase contrast magnetic resonance angiography of the cranial abdomen was performed in each dog and blood flow was independently measured in each of the major cranial abdominal vessels by three observers, with two observers recording blood flow values once and one observer recording blood flow values three times. Each dog then underwent ultrasonographic examination of the liver with fine needle aspirations and biopsies submitted to cytologic and histologic examination. The mean absolute stroke volume and velocity were respectively 9.6 ± 1.9 ml and -11.1 ± 1.1 cm/s for the cranial abdominal aorta, 2.1 ± 0.6 ml and -6.6 ± 1.9 cm/s for the celiac artery, and 2.3 ± 1.0 ml and -7.9 ± 3.1 cm/s for the cranial mesenteric artery. The mean absolute stroke volume and velocity were respectively 6.7 ± 1.3 ml and 3.9 ± 0.9 cm/s for the caudal vena cava and 2.6 ± 0.9 ml and 3.2 ± 1.2 cm/s for the portal vein. Intraobserver reliability was excellent (intraclass correlation coefficient > 0.9). Interobserver reproducibility was also excellent (intraclass correlation coefficient 0.89-0.99). Results of liver ultrasonography, cytology, and histopathology were unremarkable. Findings indicated that cardiac-gated, phase contrast magnetic resonance angiography is a feasible technique for quantifying blood blow in canine major cranial abdominal vessels. Blood flow values from this sample of healthy beagles can be used as background for future studies on canine hepatic disease.

Sensitivity and Specificity of Plasma ALT, ALP, and Bile Acids for Hepatitis in Labrador Retrievers

Background

Biochemical indicators for diagnosing liver disease are plasma alanine aminotransferase activity (ALT), alkaline phosphatase activity (ALP), and bile acid concentration (BA).

Objectives

To determine the sensitivity and specificity of ALT, ALP, and BA for detecting primary hepatitis (PH) in clinically healthy Labrador retrievers and investigate whether ALT and ALP can discriminate between dogs with PH and nonspecific reactive hepatitis (RH).

Animals

191 clinically healthy and 51 clinically ill Labrador retrievers with hepatic histopathology.

Methods

Retrospective study. Medical records were reviewed for ALT, ALP, preprandial BA, liver histopathology, and hepatic copper concentrations.

Results

In 64% (122/191) of the clinically healthy Labrador retrievers, hepatic histology revealed inflammatory infiltrates. This frequency might be biased because part of them was included as first‐line relatives of dogs with copper‐associated hepatitis. Sensitivity of ALT, ALP, and BA in this population for detecting acute hepatitis was 45, 15, and 15%, respectively. For chronic hepatitis, sensitivity was 71, 35, and 13%, respectively. Specificity of ALT, ALP, and BA was >90% for AH, CH, and RH. When increased liver enzymes were present, median ALT was significantly higher in PH cases (312 U/L, range 38–1,369) compared to RH cases (91 U/L, range 39–139) (P < .001). There was no difference in ALP between dogs with a PH and a RH (P = .361).

Conclusions and Clinical Importance

Histopathologic abnormalities in the liver were present in the majority of apparent clinically healthy Labrador retrievers. The sensitivity of ALT, ALP, and BA for detecting acute and chronic hepatitis in this population was low. More sensitive biomarkers are needed for early detection of liver disease in apparent clinically healthy dogs.

Canine Idiopathic Chronic Hepatitis

The World Small Animal Veterinary Association's Liver Standardization Group produced standardized criteria for the histologic diagnosis of canine chronic hepatitis (CH). They define CH by the presence of hepatocellular apoptosis or necrosis, a variable mononuclear or mixed inflammatory cell infiltrate, regeneration, and fibrosis. There are variations in histologic appearance between breeds. Hepatic copper accumulation is an important cause of canine CH. However, where copper accumulation has been ruled out, dogs are said to have idiopathic CH. This article reviews theories regarding the etiopathogenesis of canine CH other than copper accumulation, and its clinical features, diagnostic findings, and management.

Hepatic concentrations of copper and other metals in dogs with and without chronic hepatitis

OBJECTIVES

Defects in copper metabolism have been described in several dog breeds, and recently, it has been suggested that changes in other essential trace elements could be involved in the pathogenesis of hepatic disease. This study measured hepatic copper accumulation and its interactions with other essential trace and toxic metals in dogs diagnosed with chronic hepatitis.

METHODS

Liver samples of 20 chronic hepatitis and 20 healthy dogs were collected. Samples were acid digested, and essential metals (cobalt, copper, iron, manganese, molibdenum, selenium and zinc) and toxic metals (arsenic, cadmium, mercury and lead) were analysed by inductively-coupled plasma mass spectrometry.

RESULTS

Copper concentrations were significantly higher in dogs affected by hepatic disease than in controls. Dogs having chronic hepatitis with liver copper concentration greater than 100 mg/kg wet weight showed statistically higher cobalt, manganese and zinc concentrations than dogs having chronic hepatitis with liver copper concentrations less than 100 mg/kg wet weight and controls. Toxic metal concentrations were low - in all cases below the threshold associated with toxicity in dogs.

CLINICAL SIGNIFICANCE

Dogs with chronic hepatitis not only have increased concentrations of copper in the liver but also increased concentrations of cobalt, manganese and zinc; measurement of these elements may perhaps aid in diagnosis of liver disease in dogs.

Cellular Characterization of Multidrug Resistance P-glycoprotein, Alpha Fetoprotein, and Neovascular Endothelium-Associated Antigens in Canine Hepatocellular Carcinoma and Cirrhotic Liver

P-glycoprotein (P-gp), which is encoded by the multidrug resistance gene (MDR-1); alpha fetoprotein (AFP); and vascular endothelium-associated antigens are well-known markers for human and canine hepatic diseases. We obtained liver tissues from 5 dogs with hepatocellular carcinoma (HCC) and 12 dogs with cirrhosis, and we performed histopathologic and immunohistochemical evaluations using anti-P-gp, anti-AFP, anti-CD31, and anti-CD34 antibodies. P-gp was expressed at higher levels in HCC than in cirrhotic livers ( P < .01), and was most commonly localized in biliary canaliculi and small ductuli. AFP was localized mainly in the cytoplasm in HCC ( P < .01) and in a few cases of cirrhosis. In both HCC and cirrhosis, the AFP-positive cells were morphologically similar to normal hepatocytes and showed an even cytoplasmic distribution of AFP. The endothelial markers CD31 and CD34 were used to investigate vascular distribution. CD31 was expressed strongly in the portal area and parenchyma in HCC, but it was rarely observed in the parenchyma in cirrhosis. CD34 expression could not be detected in both HCC and cirrhosis. This study constitutes the first comprehensive study of P-gp, AFP, and endothelial markers in canine HCC and cirrhosis. The importance of these markers in HCC and cirrhosis in dogs was demonstrated and provides a more accurate basis for a definitive diagnosis of HCC and cirrhosis in dogs.

Serum C-reactive protein and S100A12 concentrations in dogs with hepatic disease

OBJECTIVES

To describe serum C-reactive protein and S100A12 concentrations in dogs with hepatic disease and to determine whether there is a relationship between the concentration of either and the severity of hepatic necroinflammation.

METHODS

Serum C-reactive protein and S100A12 concentrations were measured in 46 dogs undergoing hepatic biopsy. Dogs were divided into three groups: congenital portosystemic shunts, chronic hepatitis and hepatic neoplasia. The histological severity of hepatic necroinflammation was scored.

RESULTS

C-reactive protein and S100A12 concentrations were greater than the upper limit of the reference intervals in 39 and 26% of dogs, respectively. There was no association of disease group with C-reactive protein (P=0·1733) or S100A12 (P=0·1513) concentrations. There was a positive correlation between serum C-reactive protein concentration and hepatic necroinflammatory activity (rs =0·428, P=0·006).

CLINICAL SIGNIFICANCE

Increased serum C-reactive protein and S100A12 concentrations were observed in a subpopulation of dogs with various types of hepatic diseases, suggesting acute-phase inflammation and activation of phagocytic cells, respectively. Dogs with higher hepatic necroinflammatory activity scores tended to have higher serum C-reactive protein concentrations. Further studies are needed to confirm this finding in a larger group of dogs.

Hepatocyte-derived microRNAs as sensitive serum biomarkers of hepatocellular injury in Labrador retrievers

Common parenchymal liver diseases in dogs include reactive hepatopathies and primary hepatitis (acute or chronic). In chronic hepatitis, there is usually a long subclinical phase. Specific clinical signs become overt only when liver damage is severe and in this phase, treatment is usually less effective. Limited data are available regarding the sensitivity of liver enzyme activity or biomarkers for early detection of subclinical hepatitis. Hepatocyte-derived microRNAs (HDmiRs) were recently identified as promising biomarkers for hepatocellular injury in multiple species. Here, the potential of the HDmiRs miR-122 and miR-148a as sensitive diagnostic biomarkers for hepatocellular injury in Labrador retrievers was investigated. Samples from 66 Labrador retrievers with histologically normal livers, high hepatic copper, and with various forms of liver injury were evaluated for serum alanine aminotransferase (ALT) activity and microRNA values. Median values of HDmiR-122 were 34.6 times higher in dogs with liver injury and high ALT than in normal dogs (95% confidence intervals [CI], 13-95; P <0.001). HDmiR-122 values were significantly increased in dogs with liver injury and normal ALT (4.2 times; 95% CI, 2-12; P <0.01) and in dogs with high hepatic copper concentrations and unremarkable histopathology (2.9 times; 95% CI, 1.1-8.0; P <0.05). Logistic regression analyses demonstrated that miR-122 and miR-148a were both predictors of hepatocellular injury. The sensitivity of miR-122 was 84% (95% CI, 73-93%), making it superior to ALT (55%; 95% CI, 41-68%) for the detection of hepatocellular injury in Labrador retrievers (P <0.001). This study demonstrated that serum HDmiR, particularly miR-122, is a highly sensitive marker for the detection of hepatocellular injury in Labrador retrievers and is a promising new biomarker that may be used for early detection of subclinical hepatitis in dogs.

Total serum bilirubin as a negative prognostic factor in idiopathic canine chronic hepatitis

Total serum bilirubin (TBIL) is used as a prognostic factor in chronic hepatitis (CH) in human beings. To date, the authors are unaware of any studies looking at the value of TBIL as a prognostic factor in idiopathic canine CH. The objective of the current study was to assess if TBIL is a negative prognostic factor in idiopathic canine CH, and to identify other prognostic factors. Thirty-nine dogs with histologically confirmed idiopathic CH admitted to 2 referral centers between 1999 and 2010 were included in the study. Patients with concurrent diseases that could affect TBIL or the survival time were excluded. Total serum bilirubin was measured prior to liver biopsy, and CH was diagnosed according to standardized histological criteria. Survival time was calculated from time of diagnosis to time of death or euthanasia. Cox proportional hazard analysis was performed to identify prognostic factors. The mean survival time for the 39 dogs included in the analysis was 197 days (1-2,677), and the mean total serum bilirubin was 11 μmol/l (2-265). Total serum bilirubin was statistically significantly associated with survival (odds ratio = 1.082, P = 0.047) as were weight (odds ratio = 1.028, P = 0.028) and the presence of ascites (odds ratio = 6.758, P = 0.013). The current study demonstrates that TBIL could be used as an additional prognostic factor in canine CH.

Whole blood manganese concentrations in dogs with primary hepatitis

OBJECTIVES

Increased whole blood manganese concentrations have been reported in humans with primary liver disease. Due to the neurotoxic effects of manganese, altered manganese homeostasis has been linked to the development of hepatic encephalopathy. Whole blood manganese concentrations are increased in cases of canine congenital portosystemic shunts, but it remains unclear whether dogs with primary hepatopathies also have altered manganese homeostasis.

METHODS

Whole blood manganese concentrations were measured by graphite furnace atomic absorption spectrometry in 21 dogs with primary hepatitis, 65 dogs with a congenital portosystemic shunt, 31 dogs with non-hepatic illnesses and 18 healthy dogs.

RESULTS

The whole blood manganese concentrations were significantly different between dogs with primary hepatitis, dogs with non-hepatic illnesses and healthy dogs (P=0·002). Dogs with primary hepatitis had significantly increased whole blood manganese concentrations compared with healthy dogs (P<0·05) and dogs with non-hepatic illnesses (P<0·01). Dogs with primary hepatitis had significantly lower whole blood manganese concentration compared with dogs with congenital portosystemic shunts (P=0·0005).

CLINICAL SIGNIFICANCE

Dogs with primary hepatopathies have increased concentrations of whole blood manganese although these concentrations are not as high as those in dogs with congenital portosystemic shunts. The role of altered manganese homeostasis in canine hepatic encephalopathy is worthy of further study.

Aflatoxicose em cães na região Sul do Rio Grande do Sul

Descrevem-se os aspectos clinicopatológicos de casos de aflatoxicose em cães no Sul do Rio Grande do Sul. Foi realizado um estudo retrospectivo dos casos diagnosticados como aflatoxicose em cães necropsiados no Laboratório Regional de Diagnóstico (LRD) da Faculdade de Veterinária da Universidade Federal de Pelotas (UFPel) no período de 1978 a 2012. Em quatro casos o diagnóstico foi confirmado pela detecção de níveis de 89 a 191 ppb de aflatoxinas B1 e G1 no alimento dos cães. De um total de 27 cães com cirrose hepática, em seis havia suspeita de aflatoxicose pelas lesões macro e microscópicas e pelo tipo de alimentação que os cães recebiam. Os sinais clínicos nos casos confirmados e nos suspeitos caracterizaram-se por apatia, diarreia, icterícia e ascite, com evolução para morte em 8 a 30 dias nos casos confirmados e em 15 a 60 dias nos casos suspeitos. A dieta era à base de derivados de milho ou arroz, farelo de amendoim e, em um caso suspeito, a dieta era ração comercial. As alterações macroscópicas caracterizaram-se por ascite, icterícia, fígado aumentado de tamanho, com ou sem nódulos, hemorragia nas serosas, conteúdo intestinal hemorrágico. Os casos foram classificados de acordo com o padrão histológico principal, caracterizado por vacuolização difusa no citoplasma de hepatócitos nos casos agudos, por proliferação de ductos biliares e discreta fibroplasia nos casos subagudos e por fibrose acentuada nos casos crônicos. Aparentemente, a enfermidade não é importante como causa de morte em cães na região, no entanto, alerta-se para a possibilidade de casos com diagnóstico de cirrose hepática sem causa determinada serem causados por aflatoxicose.

Canine hepacivirus is not associated with chronic liver disease in dogs

Canine hepacivirus (CHV) has recently been identified in liver and respiratory tract samples from dogs, and comparative phylogenetic analysis has confirmed it to be the closest genetic relative of hepatitis C virus (HCV) described to date. CHV offers great potential as a model system for HCV, but only if the underlying processes of infection and pathogenesis are similar for both viruses. However, it is not yet clear if CHV is hepatotrophic. Canine chronic hepatitis (CH) is a common and usually idiopathic disease that shares similar histological features to that of HCV infection of humans. To date, no study has attempted to determine whether CHV is involved in the aetiology of liver disease in dogs. We employed two nested PCR assays, using primers targeting regions of the helicase domain of CHV NS3, to identify viral nucleic acids in liver samples from 100 dogs with CH of unknown cause in the UK. We also used a sensitive luciferase immunoprecipitation system (LIPS) assay to screen serum samples from these dogs for the presence of anti-CHV antibodies. Surprisingly, there was no evidence of exposure to, or a carrier state of, CHV in this large cohort, suggesting that the virus is not associated with CH in UK dogs. Future work, including transmission studies, is required to understand the pathogenesis of CHV in canids before it can be proposed as a surrogate model for HCV-induced liver disease in man.

Potential of regenerative medicine techniques in canine hepatology

Liver cell turnover is very slow, especially compared to intestines and stomach epithelium and hair cells. Since the liver is the main detoxifying organ in the body, it does not come as a surprise that the liver has an unmatched regenerative capacity. After 70% partial hepatectomy, the liver size returns to normal in about two weeks due to replication of differentiated hepatocytes and cholangiocytes. Despite this, liver diseases are regularly encountered in the veterinary clinic. Dogs primarily present with parenchymal pathologies such as hepatitis. The estimated frequency of canine hepatitis depends on the investigated population and accounts for 1%-2% of our university clinic referral population, and up to 12% in a general population. In chronic and severe acute liver disease, the regenerative and replicative capacity of the hepatocytes and/or cholangiocytes falls short and the liver is not restored. In this situation, proliferation of hepatic stem cells or hepatic progenitor cells (HPCs), on histology called the ductular reaction, comes into play to replace the damaged hepatocytes or cholangiocytes. For unknown reasons the ductular reaction is often too little and too late, or differentiation into fully differentiated hepatocytes or cholangiocytes is hampered. In this way, HPCs fail to fully regenerate the liver. The presence and potential of HPCs does, however, provide great prospectives for their use in regenerative strategies. This review highlights the regulation of, and the interaction between, HPCs and other liver cell types and discusses potential regenerative medicine-oriented strategies in canine hepatitis, making use of (liver) stem cells.

The feline bile salt export pump: a structural and functional comparison with canine and human Bsep/BSEP

Background

The bile salt export pump (BSEP/ABCB11) is the primary transporter for the excretion of bile acids from hepatocytes into bile. In human, inhibition of BSEP by drugs has been related to drug-induced cholestasis and subsequent cytotoxic effects. The role of BSEP in canine and feline liver diseases has not been studied in detail, but the same mechanism of inhibition by drugs as in humans could play a role in veterinary medicine. The aim of this study was to investigate the functional characteristics of feline Bsep in comparison with canine and human Bsep/BSEP with respect to substrate affinities and inhibitory potential of model drugs. Orthologs of all three species were cloned and cell membrane vesicles overexpressing feline, canine and human Bsep/BSEP were prepared for functional analyses.

Results

The cDNA sequences of the open reading frames of feline, canine and human Bsep/BSEP showed a high similarity between the species. Functional studies demonstrated for all species a tendency to a higher affinity of BSEP/Bsep for the conjugated bile acid taurocholic acid (TCA) than glycocholic acid (GCA), and a higher affinity for GCA than for the unconjugated cholic acid (CA). The inhibitory potency of the model inhibitors cyclosporine A, troglitazone and ketoconazole was characterized against TCA uptake into BSEP/Bsep containing membrane vesicles. All three substances potently inhibited TCA uptake without significant species differences.

Conclusion

Structure and functional characteristics of cat, dog and human Bsep/BSEP appeared to be very similar, indicating that the properties of this transporter have been highly preserved among the different species. Therefore, inhibition of BSEP by drugs could also be a mechanism in cholestasis and liver disease in veterinary relevant animal species. This model could be used to predict drug-induced liver injury caused by BSEP inhibition at an early stage in veterinary drug development.

A retrospective study of oral prednisolone treatment in canine chronic hepatitis

BACKGROUND

Only one study reports prednisone to prolong survival in dogs with chronic hepatitis irrespective of the causative agent. The aim of this retrospective study was to investigate the effects of prednisolone treatment on survival, clinicopathological variables, and histological grade and stage of idiopathic chronic hepatitis in 36 dogs.

ANIMALS AND METHODS

Medical records were reviewed of 36 prednisolone-treated dogs (median age: 8.6 years; range: 2.0-14.6 years) with chronic hepatitis not associated with primary copper accumulation. Clinicopathological results were analyzed pair-wise for 20 dogs, before and after oral prednisolone administration (1 mg/kg BW/day). Dogs were treated for at least 6 weeks, and for an additional 6 weeks if hepatitis was still present at rebiopsy. Follow-up data pertaining to clinical outcome and survival time (Kaplan-Meier estimate procedure) were analyzed.

RESULTS

At the follow-up, 11 dogs were in complete remission, 8 dogs had recurrent clinical signs, and 17 dogs had residual disease. Despite treatment, 20 dogs died of hepatitis-related causes. Dogs without cirrhosis survived significantly longer than dogs with cirrhosis. Prednisolone treatment normalized coagulopathies associated with chronic idiopathic hepatitis within one week in all 10 dogs that had coagulopathies at initial diagnosis.

CONCLUSIONS

Our findings suggest that prednisolone has, in part, beneficial effects on hepatic inflammation and that it may, at least in some cases, limit the progression of fibrosis, which emphasizes the importance of early diagnosis and treatment. We did not see any benefit of prednisolone treatment for dogs with cirrhosis. We could document a highly favorable effect of prednisolone treatment on the coagulopathy associated with canine chronic idiopathic hepatitis.

Imaging diagnosis-ultrasonographic and CT findings in a gray seal (Halichoerus grypus) with hepatic cirrhosis, pyelonephritis, and nephrolithiasis

An immature gray seal was presented with lethargy, weight loss, vomiting and hematuria. Hepatic disease and urinary tract infection were suspected. Abdominal ultrasound showed hyperechoic structures with marked acoustic shadowing spread throughout both kidneys, but incomplete visualization of the liver. Abdominal CT showed mineral densities scattered throughout both kidneys and poor delineation of the liver. Due to the poor quality of life, the seal was euthanized. Postmortem examination showed ammonium urate nephroliths, pyelonephritis, and hepatic cirrhosis. This case report emphasizes the difficulty of characterizing liver disease with conventional 2D-ultrasound and CT in a deep-chested animal with minimal intra-abdominal fat.

The role of hepatic myofibroblasts in liver cirrhosis in fallow deer (Dama dama) naturally infected with giant liver fluke (Fascioloides magna)

Background

This paper describes liver cirrhosis in 35 fallow deer infected with the giant liver fluke, as well as the distribution, origin, and role of myofibroblasts in its development.

Results

In liver of infected deer, stripes of connective tissue are wound around groups of degenerated and regenerated liver lobuli. In the connective tissue, lymphocytes and macrophages which often contain parasite hematin are also present. The walls of the bile ducts are thickened, the epithelium multiplied with mucous metaplasia, and desquamated cells, parasite eggs and brown pigment are present in their lumen.

In the livers with cirrhosis, immunopositivity to α-SMA and desmin was observed in cells in portal and septal spaces, at the edge between fibrotic septa and the surrounding parenchyma and in perisinusoidal spaces. These cells vary in size, they are round, oval, spindle-shaped or irregular in shape, similar to vascular smooth muscle cells. The derangement of epithelial-mesenchymal interactions detected in chronic cholangiopathies is most probably the pro-fibrogenic mechanism in liver cirrhosis of fallow deer (Dama dama) infected with the giant liver fluke (Fascioloides magna).

Conclusion

Myofibroblasts, especially hepatic stellate cells (HSCs), play an important role in the synthesis of extracellular matrix components in the development of parasitic fibrosis and cirrhosis in the liver of fallow deer.

The immunopathogenetic role of autoantibodies in canine autoimmune hepatitis: lessons to learn from human autoimmune hepatitis

Autoimmune hepatitis (AIH) is not a disease entity restricted to man, but it can be found in other animals including canines. An increasing number of studies have focused on the immunopathogenesis of human autoimmune hepatitis (hAIH), but little is known of what triggers canine autoimmune hepatitis (cAIH). Several drugs, toxins, microbial and viral agents are able to induce autoantibodies and indeed immune-mediated chronic canine hepatitis with immunological and serological features similar of those seen in the human disease. We discuss the features of cAIH paying attention to the autoantibody profile of the disease in comparison to that seen in hAIH. We also discuss the immunomodulatory role of specific molecular signaling pathways such as those mediated by tumor growth factor and p38 mitogen-activated kinase in the induction of AIH, and the potential of these molecules to act as targets of specialized immunotherapeutic interventions. Review of the literature indicates that we have more to learn for the delineation of autoantibody profile and the antigen-specific immunoregulatory mechanisms involved in the pathogenesis of cAIH from the human disease, rather than the other way around.

DLA class II alleles and haplotypes are associated with risk for and protection from chronic hepatitis in the English Springer spaniel

Chronic hepatitis (CH) is common in dogs in the United Kingdom. An increased prevalence of the disease is seen in the English Springer spaniel (ESS), and this breed suffer from a severe form with young to middle aged female dogs being predisposed. The disease shares histological features with those of human viral hepatitis, although the specific aetiological agent has not yet been identified. The aim of the current study was to investigate whether dog leucocyte antigen (DLA) class II alleles and haplotypes are associated with susceptibility/resistance to CH in the ESS. Sequence-based genotyping of the polymorphic exon 2 from DLA-DRB1, -DQA1 and -DQB1 class II loci were performed in 66 ESSs with CH and 84 healthy controls. There was a significant difference in the distribution of the protective alleles DRB1*00501 (3.0% vs. 12.0%, odds ratio [OR] = 0.23, 95% confidence interval [CI] = 0.06–0.74) and DQB1*00501 (3.8% vs. 12.0%, OR = 0.29, 95% CI = 0.09–0.85) between cases and controls. The haplotype DLA-DRB1*00501/DQA1*00301/DQB1*00501 was present in 11.9% of controls and 3.0% of cases and was significantly associated with protection against disease development (OR = 0.26, 95% CI = 0.08–0.80). There was a significant difference in the distribution of the risk alleles DRB1*00601 (14.4% vs. 6.5%, OR = 2.40, 95% CI = 1.10–5.63) and DQB1*00701 (14.4% vs. 6.5%, OR = 2.40, 95% CI = 1.10–5.63) between cases and controls. A risk haplotype (DLA-DRB1*00601/DQA1*005011/DQB1*00701) was present in 14.4% of cases and 6.5% of controls and conferred an elevated risk of developing CH with an OR of 3.13 (95% CI = 1.20–8.26). These results demonstrate that DLA class II is significantly associated with risk and protection from developing CH in ESSs.

Therapeutic potential of canine bone marrow stromal cells (BMSCs) in the carbon tetrachloride (CCl4) induced chronic liver dysfunction mouse model

Regenerative medicine using bone marrow cells is an attractive therapy for the cure of patients with severe liver disease. Here, we show the therapeutic potential of canine bone marrow stromal cells (BMSCs) in mouse models of CCl(4)-induced chronic liver dysfunction. We used two different models for xenotransplantation, nude mice and cyclosporine A (CSA) immunosuppressed mice. Serum parameters from a standard liver panel were not improved following transplantation. However, fibrotic liver lesions with severe inflammation were decreased in CCl(4)-treated CSA mice following BMSC transplantation. Effective migration of transplanted canine BMSCs was limited to persistently injured liver in CCl(4)-treated CSA mice, where they may be effective in resolving inflammatory fibrotic lesions. These results suggest that canine BMSCs are an effective cell source for liver regeneration.

Chronic hepatitis in the English springer spaniel: clinical presentation, histological description and outcome

Medical records and liver histology of 68 English springer spaniels (ESS) with a histological diagnosis of CH were reviewed retrospectively. PCR was performed on liver tissue for canine adenovirus-1 (CAV-1), canine parvovirus, canine herpesvirus and pathogenic Leptospira species. Follow-up information was obtained to calculate survival times. Median age at presentation was three years seven months (range, seven months to eight years five months) and there were 48 female and 20 male dogs. Clinical signs were non-specific and five dogs were asymptomatic. All dogs had an increase in serum activity of one or more hepatobiliary enzymes. Histopathology demonstrated hepatocyte necrosis and apoptosis with varying amounts of fibrosis. A predominantly lymphoplasmacytic infiltrate throughout the hepatic parenchyma was found in all 68 dogs, but 45 of these dogs also had a neutrophilic component to the inflammatory infiltrate. There was no significant copper accumulation and no aetiological agent was identified by PCR. The median survival time was 189 days (range, 1 to 1211 days), 38 dogs died within three months and 12 dogs survived more than a year following diagnosis.

Expression of fibrosis-related genes in canine chronic hepatitis

Molecular regulation of fibrosis in chronic canine hepatitis is poorly understood. The authors employed quantitative polymerase chain reaction (PCR) to determine the expression levels of genes reported to be related to fibrosis in other species (human, mouse, and rat) and to elucidate the relationship of these genes with the degree of fibrosis and the presence or absence of ascites and/or jaundice in dogs with hepatitis. Nine fibrosis-related genes were assayed: PDGFB, PDGFD, MMP2, TIMP1, THBS1, COL1A1, COL3A1, TGFB1, and TGFB2. Liver samples of 15 dogs with chronic hepatitis and 4 healthy control dogs were obtained via laparoscopic biopsy and subjected to histologic and quantitative PCR analyses. The expression of all 9 genes showed significant positive correlation (P<.01, r>.70) with the degree of fibrosis. Furthermore, the expression levels of all genes except TGFB1 were significantly higher (P<.05) in dogs with hepatic failure-related symptoms (ascites/jaundice). Results suggest that these 9 genes are integral to the development of fibrosis in canine chronic hepatitis.

Prevalence of hepatic lesions at post-mortem examination in dogs and association with pancreatitis

OBJECTIVES

To assess the prevalence of canine chronic hepatitis (CH) and other liver diseases in first opinion practice and identify associations with concurrent chronic pancreatitis (CP).

METHODS

One large section of left lateral lobe of liver was taken from 200 unselected canine post-mortem examinations from first opinion practices. Histological changes were categorised based on WSAVA criteria. Prevalence of CH and other liver diseases were calculated. Relative risks (RR) for liver histopathology in association with CP and for CH in different breeds were also calculated.

RESULTS

The prevalence of CH was 12%. Some breeds had an increased RR of CH, although sample sizes were small. Dogs with CP had an increased RR of reactive hepatitis but no significant association with the other liver diseases.

CLINICAL SIGNIFICANCE

CH is common in the first opinion dog population but less common than CP. CP was significantly associated with reactive hepatitis but not CH. Possible breed associations mirrored another recent UK study. Some dogs with CP may be erroneously diagnosed clinically as having CH on the basis of increased serum liver enzymes because of concurrent reactive hepatitis if the diagnosis is not confirmed histologically.

Animal models of autoimmune hepatitis

Animal models of autoimmune hepatitis have been important in defining pathogenic mechanisms, and they promise to aid in the evaluation of new molecular and cellular treatments. They have evolved from models based on crude liver homogenates that produced a transient hepatitis to models that express antibodies to human antigens, manifest liver-infiltrating T cells, persist for at least 3 months and develop fibrosis. Animal models allow the study of autoimmune hepatitis from its inception, and they can detail the progression of pathological events. Key imbalances in counter-regulatory mechanisms can be isolated and manipulated. Models can be humanized by the insertion of human genetic promoters and the expression of human antigens. Genetic engineering and preconditioning have been milestones in the evolution of animal models. Vaccination or infection of murine models with viral vectors carrying human antigens are the most recent developments. Animal models promise to extend the knowledge of etiological agents and improve treatment algorithms.

Primary hepatitis in dogs: a retrospective review (2002-2006)

BACKGROUND

Little is known about etiology, disease progression, treatment outcome, survival time, and factors affecting prognosis in dogs with primary hepatitis (PH).

OBJECTIVES

To review retrospectively different forms of hepatitis in a referral population, by the World Small Animal Veterinary Association Standardization criteria.

ANIMALS

One-hundred and one dogs examined for histologically confirmed PH between 2002 and 2006. Dogs with nonspecific reactive hepatitis were excluded.

METHODS

Retrospective study. Medical records were reviewed for prevalence, signalment, clinical and clinicopathologic manifestation, outcome, survival time, and prognostic factors for shortened survival.

RESULTS

PH occurred in 0.5% of dogs in this referral population. Acute (AH) and chronic hepatitis (CH) were diagnosed in 21 and 67 dogs, respectively. Progression from AH to CH occurred in 5/12 of the repeatedly sampled dogs. CH was idiopathic in 43 (64%) dogs, and was associated with copper accumulation in 24 (36%) dogs. Median survival time was longer in dogs with AH than in dogs with CH (either idiopathic or copper associated), and dogs with lobular dissecting hepatitis had the shortest survival time. Prognostic factors predicting shortened survival were associated with decompensated liver function and cirrhosis at initial examination.

CONCLUSIONS AND CLINICAL IMPORTANCE

The majority of PH in dogs is CH. Previous studies appear to have underestimated the etiologic role of copper in both AH and CH. Prognosis is reduced in dogs with hepatic cirrhosis or cirrhosis-related clinical findings. Further research into etiology and treatment effectiveness in all PH forms is needed.

Ascites is a negative prognostic indicator in chronic hepatitis in dogs

BACKGROUND

Chronic hepatitis (CH) in dogs is common but little is known about factors associated with survival. Ascites is a well-recognized negative prognostic indicator in humans.

HYPOTHESIS

Ascites is a negative prognostic indicator in CH in dogs.

ANIMALS

Thirty-four dogs with histologically confirmed CH presented to 1 institution between 1996 and 2005.

METHODS

Retrospective observational study. CH was diagnosed by histopathology of liver tissue according to the WSAVA criteria. Ascites was diagnosed by abdominal ultrasound. The association of ascites with survival from diagnosis or onset of owner-reported clinical signs until death from any cause or from liver disease was analyzed. Ascitic and nonascitic groups were further analyzed for differences in treatment and sex.

RESULTS

Fourteen of 34 dogs had ascites. Survival from diagnosis to death from liver disease was 0.4 months (95% confidence interval [CI], 0.2-0.6) for ascitic dogs and 24.3 months (CI 11.4-37.1) for nonascitic dogs (P < .001), and from onset of signs to death from liver disease was 2.0 months (CI 0.0-5.6) for ascitic dogs and 33.0 months (CI 8.6-57.4) for nonascitic dogs (P= .0020). Diet and spironolactone use differed between groups.

CONCLUSIONS AND CLINICAL IMPORTANCE

Ascites is a significant negative prognostic indicator in dogs with CH. Veterinarians and owners can use this information to aid clinical decision making in affected dogs.

Expression and distribution of connexin 32 in rat liver with experimentally induced fibrosis

The connexin 32 (Cx32) is a protein that forms the channels that promote the gap junction intercellular communication (GJIC) in the liver, allowing the diffusion of small molecules through cytosol from cell-to-cell. Hepatic fibrosis is characterized by a disruption of normal tissue architeture by cellular lesions, and may alter the GJIC. This work aimed to study the expression and distribution of Cx32 in liver fibrosis induced by the oral administration of dimethylnitrosamine in female Wistar rats. The necropsy of the rats was carried out after five weeks of drug administration. They presented a hepatic fibrosis state. Sections from livers with fibrosis and from control livers were submitted to immunohistochemical, Real Time-PCR and Western-Blot analysis to Cx32. In fibrotic livers the Cxs were diffusely scattered in the cytoplasm, contrasting with the control livers, where the Cx32 formed junction plaques at the cell membrane. Also it was found a decrease in the gene expression of Cx32 without reduction in the protein quantity when compared with controls. These results suggest that there the mechanism of intercellular communication between hepatocytes was reduced by the fibrotic process, which may predispose to the occurrence of a neoplastic process, taken in account that connexins are considered tumor suppressing genes.

Canine bone marrow cells differentiate into hepatocyte-like cells and placental hydrolysate is a potential inducer

Hepatocyte growth factor (HGF) can stimulate human and rat bone marrow (BM) cells to differentiate into hepatocytes. A human placental hydrolysate (hPH) stimulates proliferation of hepatocytes, but its role as a potential inducer of BM cells to form hepatocytes is unclear. To determine if canine BM cells stimulated with HGF or hPH differentiate into hepatocyte-like cells, BM cells were cultured with HGF or hPH. The cultured cells underwent morphological examination, expression of albumin and cytokeratin 18 (CK18), hepatic function tests including uptake of low-density lipoprotein (LDL) and cytochrome P (CYP) 450 activity. Albumin mRNA and protein expression of albumin and CK18 proteins were detected in cultures with HGF and hPH. Furthermore, these cells demonstrated LDL uptake and CYP450 activity. These results indicate that canine BM cells can differentiate into hepatocyte-like cells when stimulated by both HGF and that hPH may be an effective inducer of hepatic differentiation.

Cirrose hepática em cães: 80 casos (1965-2003)

Foi realizado um estudo retrospectivo de 80 casos de cirrose em cães no Laboratório de Patologia Veterinária da Universidade Federal de Santa Maria, Rio Grande do Sul. Dos cães em que o sexo e a idade constavam dos protocolos de necropsia, 53,8% eram machos e 46,2% eram fêmeas; 50,0% foram incluídos como idosos, 48,6% como adultos e 1,4% como filhote. Os principais sinais clínicos observados incluíram: ascite (39/80 [48,8%]), icterícia (19/80 [23,8%]), anorexia (13/80 [16,2%]), distúrbios neurológicos (12/80 [15,0%]), dispnéia (12/80 [15,0%]) e edema subcutâneo (10/80 [12,5%]). Dos 63 cães em que a descrição macroscópica constava dos protocolos de necropsia, 76,2% tinham cirrose macronodular e 23,8% tinham cirrose micronodular. Nos 14 cães em que as lesões histológicas foram revistas pode-se observar diferentes graus de fibrose (leve [57,2%], moderada [21,4%] ou acentuada [21,4%]) e nenhuma relação entre as intensidades da fibrose e das outras lesões histológicas observadas (degeneração gordurosa, proliferação de ductos biliares, inflamação, bilestase, hemossiderose e necrose aleatória de hepatócitos). As alterações macro e microscópicas extra-hepáticas incluíram: ascite (39/63 [61,9%]), icterícia (19/63 [30,2%]), status spongiosus (15/63 [23,8%]), hidrotórax (12/63 [19,0%]), edema subcutâneo (10/63 [15,9%]), derivações portossistêmicas (11/63 [17,5%]), úlceras gástricas ou duodenais (11/63 [17,5%]) e nefrose colêmica (4/63 [6,3%]).