Expression of fibrosis-related genes in canine chronic hepatitis

Dental Abnormalities in Two Dental-Skeletal-Retinal Anomaly-Positive Cane Corso Dogs: A Case Series

Dental-skeletal-retinal-anomaly (DSRA) is a newly described collagenopathy in Cane Corso dogs. The causative mutation has been linked with splice defects within the melanoma inhibitory activity member 3 (MIA/3) gene that codes for the TANGO1 protein. This case series presents the first dental-related radiographic and histopathological abnormalities in two dogs with genetically confirmed DSRA. The clinical, radiological, and histological features are similar to those reported for MIA3/TANGO1 splice defects previously reported in humans and knockout mice. Common clinical features of these patients include generalized opalescent discoloration of the permanent dentition (intrinsic dyschromia), enamel defects, fractured teeth, vision loss, shortened physical stature, and orthopedic abnormalities that resulted in chronic, early-onset lameness. Intraoral radiography revealed delayed dentin deposition, evidence of endodontic disease, and dental hard tissue loss in both cases. Histopathologic findings for both cases were consistent with dentinogenesis imperfecta (DGI). DSRA exhibits autosomal recessive heritability and commercial diagnostic tests are now available. Clinicians should be aware of the etiopathogenesis, genetic inheritance and associated comorbidities in order to treat and counsel clients on the management of this condition. It is recommended that all breeding individuals be tested, and carriers be sterilized or omitted from the breeding population. This case study describes intraoral diagnoses, treatments, and follow-up of two DSRA-positive dogs.

Plasma renin activity and aldosterone concentration in dogs with acquired portosystemic collaterals

Background

The renin‐angiotensin‐aldosterone system (RAAS) is activated in humans with portal hypertension (PH) associated with liver disease. However, involvement of RAAS in dogs with intrahepatic PH is not clear.

Objective

To measure plasma renin activity (PRA) and plasma aldosterone concentration (PAC) in dogs with PH (chronic hepatitis [CH] and primary hypoplasia of the portal vein [PHPV]), dogs with extrahepatic congenital portosystemic shunt (EH‐CPSS), and healthy dogs and to determine whether the RAAS is activated in dogs with PH.

Animals

Twenty‐seven dogs with acquired portosystemic collaterals (APSCs; 15 dogs with CH, 12 dogs with PHPV), 9 dogs with EH‐CPSS, and 10 healthy dogs.

Methods

Retrospective study. Plasma renin activity and PAC were measured by radioimmunoassay.

Results

Plasma renin activity was significantly higher in the CH group (median, 4.4 ng/mL/h) than in the EH‐CPSS (median, 1.0 ng/mL/h; P < .01) and the healthy (median, 1.1 ng/mL/h; P < .01) groups. No significant differences were found between the PHPV group (median, 2.2 ng/mL/h) and other groups. Plasma aldosterone concentration was significantly higher in the CH (median, 111.0 pg/mL) and PHPV (median, 89.5 pg/mL) groups than in the EH‐CPSS (median, 1.0 pg/mL; P < .001, P < .01, respectively) and healthy (median, 14.5 pg/mL; P < .001, P < .05, respectively) groups.

Conclusions and Clinical Importance

Activation of the RAAS contributes to the pathophysiology of intrahepatic PH in dogs, suggesting that spironolactone may not only be effective for the treatment of ascites but also for the suppression of intrahepatic PH.

Liver regeneration therapy through the hepatic artery-infusion of cultured bone marrow cells in a canine liver fibrosis model

Background

We previously reported regenerative therapies for decompensated cirrhosis based on peripheral venous drip infusion using non-cultured whole bone marrow (BM) cells, or the less invasive cultured BM-derived mesenchymal stem cells (BMSCs). Here, we assessed the efficacy and safety of hepatic arterial infusion using cultured autologous BMSCs, comparing it with peripheral infusion, using our established canine liver fibrosis model.

Methods

Canine BM cells were harvested and cultured, and the resultant BMSCs were returned to carbon tetrachloride (CCl₄)-induced liver cirrhosis model canines via either a peripheral vein (Vein group) or hepatic artery (Artery group). A variety of assays were performed before and 4, 8, and 12 weeks after BMSC infusion, and liver fibrosis and indocyanine green (ICG) half-life (t_1/2) were compared to those in a control group that received CCl₄ but not BMSCs. The safety of this approach was evaluated by contrast-enhanced computed tomography (CT) and serial blood examinations after infusion.

Results

Four weeks after infusing BMSCs, a significant improvement was observed in the Vein group (n = 8) compared to outcome in the Control group (n = 10), along with a decrease in ICG t_1/2. In the Artery group (n = 4), ICG t_1/2 was significantly shorter than that in the Vein group at 8 weeks (Δt_1/2: −3.8 ± 1.7 min vs. +0.4 ± 2.4 min; p < 0.01) and 12 weeks (Δt_1/2: −4.2 ± 1.7 min vs. +0.4 ± 2.7 min; p < 0.01) after BMSC administration. Post-infusion contrast-enhanced CT showed no liver infarction, and blood tests showed no elevations in either serum lactate dehydrogenase concentrations or hypercoagulability.

Conclusions

We confirmed the efficacy and safety of the hepatic arterial infusion of cultured autologous BMSCs using a canine model, thereby providing non-clinical proof-of-concept.

Hepatic Fibrosis in Dogs

Hepatic fibrosis is commonly diagnosed in dogs, often as a sequela to chronic hepatitis (CH). The development of fibrosis is a crucial event in the progression of hepatic disease that is of prognostic value. The pathophysiology of hepatic fibrosis in human patients and rodent models has been studied extensively. Although less is known about this process in dogs, evidence suggests that fibrogenic mechanisms are similar between species and that activation of hepatic stellate cells is a key step. Diagnosis and staging of hepatic fibrosis in dogs requires histopathological examination of a liver biopsy specimen. However, performing a liver biopsy is invasive and assessment of fibrotic stage is complicated by the absence of a universally accepted staging scheme in veterinary medicine. Serum biomarkers that can discriminate among different fibrosis stages are used in human patients, but such markers must be more completely evaluated in dogs before clinical use. When successful treatment of its underlying cause is feasible, reversal of hepatic fibrosis has been shown to be possible in rodent models and human patients. Reversal of fibrosis has not been well documented in dogs, but successful treatment of CH is possible. In human medicine, better understanding of the pathomechanisms of hepatic fibrosis is leading to the development of novel treatment strategies. In time, these may be applied to dogs. This article comparatively reviews the pathogenesis of hepatic fibrosis, its diagnosis, and its treatment in dogs.

The pathogenesis of diclofenac induced immunoallergic hepatitis in a canine model of liver injury

Hypersensitivity to non-steroidal anti-inflammatory drugs is a common adverse drug reaction and may result in serious inflammatory reactions of the liver. To investigate mechanism of immunoallergic hepatitis beagle dogs were given 1 or 3 mg/kg/day (HD) oral diclofenac for 28 days. HD diclofenac treatment caused liver function test abnormalities, reduced haematocrit and haemoglobin but induced reticulocyte, WBC, platelet, neutrophil and eosinophil counts. Histopathology evidenced hepatic steatosis and glycogen depletion, apoptosis, acute lobular hepatitis, granulomas and mastocytosis. Whole genome scans revealed 663 significantly regulated genes of which 82, 47 and 25 code for stress, immune response and inflammation. Immunopathology confirmed strong induction of IgM, the complement factors C3&B, SAA, SERPING1 and others of the classical and alternate pathway. Alike, marked expression of CD205 and CD74 in Kupffer cells and lymphocytes facilitate antigen presentation and B-cell differentiation. The highly induced HIF1A and KLF6 protein expression in mast cells and macrophages sustain inflammation. Furthermore, immunogenomics discovered 24, 17, 6 and 11 significantly regulated marker genes to hallmark M1/M2 polarized macrophages, lymphocytic and granulocytic infiltrates; note, the latter was confirmed by CAE staining. Other highly regulated genes included alpha-2-macroglobulin, CRP, hepcidin, IL1R1, S100A8 and CCL20. Diclofenac treatment caused unprecedented induction of myeloperoxidase in macrophages and oxidative stress as shown by SOD1/SOD2 immunohistochemistry. Lastly, bioinformatics defined molecular circuits of inflammation and consisted of 161 regulated genes.

Altogether, the mechanism of diclofenac induced liver hypersensitivity reactions involved oxidative stress, macrophage polarization, mastocytosis, complement activation and an erroneous programming of the innate and adaptive immune system.

A canine liver fibrosis model to develop a therapy for liver cirrhosis using cultured bone marrow-derived cells

We have been developing a therapy for liver cirrhosis using cultured autologous bone marrow-derived mesenchymal stem cells (BMSCs). Before human clinical trials can be considered, the safety and efficacy of BMSC infusion in medium to large animals must be confirmed; thus, we developed a canine liver fibrosis model. A small amount of bone marrow fluid was aspirated from the canine humerus to assess the characteristics of BMSCs. We implanted a venous catheter in the stomach and a subcutaneous infusion port in the back of the neck of each canine. Repeated injection of CCl₄ through the catheter was performed to induce liver cirrhosis. After 10 weeks of CCl₄ injection, eight canines were equally divided into two groups: no cell infusion (control group) and autologous BMSC infusion through the peripheral vein (BMSC group). A variety of assays were carried out before and 4 weeks after the infusion. The area of liver fibrosis stained with sirius red was significantly reduced in the BMSC group 4 weeks after BMSC infusion, consistent with a significantly shortened half-life of indocyanine green and improved liver function. Conclusion: We established a useful canine liver fibrosis model and confirmed that cultured autologous BMSC infusion improved liver fibrosis without adverse effects. (Hepatology Communications 2017;1:691-703).

Gene expression patterns in the progression of canine copper-associated chronic hepatitis

Copper is an essential trace element, but can become toxic when present in abundance. The severe effects of copper-metabolism imbalance are illustrated by the inherited disorders Wilson disease and Menkes disease. The Labrador retriever dog breed is a novel non-rodent model for copper-storage disorders carrying mutations in genes known to be involved in copper transport. Besides disease initiation and progression of copper accumulation, the molecular mechanisms and pathways involved in progression towards copper-associated chronic hepatitis still remain unclear. Using expression levels of targeted candidate genes as well as transcriptome micro-arrays in liver tissue of Labrador retrievers in different stages of copper-associated hepatitis, pathways involved in progression of the disease were studied. At the initial phase of increased hepatic copper levels, transcriptomic alterations in livers mainly revealed enrichment for cell adhesion, developmental, inflammatory, and cytoskeleton pathways. Upregulation of targeted MT1A and COMMD1 mRNA shows the liver's first response to rising intrahepatic copper concentrations. In livers with copper-associated hepatitis mainly an activation of inflammatory pathways is detected. Once the hepatitis is in the chronic stage, transcriptional differences are found in cell adhesion adaptations and cytoskeleton remodelling. In view of the high similarities in copper-associated hepatopathies between men and dog extrapolation of these dog data into human biomedicine seems feasible.

Hepatic and Plasma Endothelin-1 in Dogs with Chronic Hepatitis

BACKGROUND

Endothelin (ET)-1 is a 21-amino-acid peptide with potent vasoactive properties, which increases intrahepatic resistance in patients with chronic hepatitis (CH) or cirrhosis. ET-1 concentrations have not been investigated in dogs with CH.

HYPOTHESIS/OBJECTIVES

This study compared hepatic and plasma ET-1 levels in healthy dogs and in dogs with CH, and examined the relationship between the plasma ET-1 level and portal vein pressure in dogs with CH.

ANIMALS

Fourteen healthy dogs and twenty dogs with CH were used in this study.

METHODS

Prospective case-control study. Hepatic ET-1 mRNA expression was determined by real-time reverse transcription polymerase chain reaction, and hepatic and plasma ET-1 levels were assessed using ELISA. Splenic pulp pressure (SPP), as an indicator of portal vein pressure, was measured laparoscopically.

RESULTS

Hepatic ET-1 mRNA levels were 3.7 times higher in dogs with CH than in healthy dogs (P = .008). The median hepatic and plasma ET-1 protein levels were significantly higher in dogs with CH than in healthy dogs (13.20 pg/mg wet liver vs. 3.42 pg/mg wet liver, P = .004, and 0.99 pg/mL vs. 0.71 pg/mL, P = .013, respectively). Moreover, there was a weak but significant correlation between plasma ET-1 level and SPP in dogs with CH (P = .036; r_s = 0.53).

CONCLUSIONS AND CLINICAL IMPORTANCE

The results indicate that ET-1 might play an important role in the pathogenesis of portal hypertension caused by CH.

Up-regulated extracellular matrix components and inflammatory chemokines may impair the regeneration of cholestatic liver

Although the healthy liver is known to have high regenerative potential, poor liver regeneration under pathological conditions remains a substantial problem. We investigated the key molecules that impair the regeneration of cholestatic liver. C57BL/6 mice were randomly subjected to partial hepatectomy and bile duct ligation (PH+BDL group, n = 16), partial hepatectomy only (PH group, n = 16), or sham operation (Sham group, n = 16). The liver sizes and histological findings were similar in the PH and sham groups 14 days after operation. However, compared with those in the sham group, the livers in mice in the PH+BDL group had a smaller size, a lower cell proliferative activity, and more fibrotic tissue 14 days after the operation, suggesting the insufficient regeneration of the cholestatic liver. Pathway-focused array analysis showed that many genes were up- or down-regulated over 1.5-fold in both PH+BDL and PH groups at 1, 3, 7, and 14 days after treatment. Interestingly, more genes that were functionally related to the extracellular matrix and inflammatory chemokines were found in the PH+BDL group than in the PH group at 7 and 14 days after treatment. Our data suggest that up-regulated extracellular matrix components and inflammatory chemokines may impair the regeneration of cholestatic liver.

X-Linked Hereditary Nephropathy in Navasota Dogs: Clinical Pathology, Morphology, and Gene Expression During Disease Progression

X-linked hereditary nephropathy (XLHN) in Navasota dogs is a spontaneously occurring disease caused by a mutation resulting in defective production of type IV collagen and juvenile-onset renal failure. The study was aimed at examining the evolution of renal damage and the expression of selected molecules potentially involved in the pathogenesis of XLHN. Clinical data and renal samples were obtained in 10 XLHN male dogs and 5 controls at 4 (T0), 6 (T1), and 9 (T2) months of age. Glomerular and tubulointerstitial lesions were scored by light microscopy, and the expression of 21 molecules was investigated by quantitative real-time polymerase chain reaction with selected proteins evaluated by immunohistochemistry. No significant histologic lesions or clinicopathologic abnormalities were identified in controls at any time-point. XLHN dogs had progressive proteinuria starting at T0. At T1, XLHN dogs had a mesangioproliferative glomerulopathy with glomerular loss, tubular necrosis, and interstitial fibrosis. At T2, glomerular and tubulointerstitial lesions were more severe, particularly glomerular loss, interstitial fibrosis, and inflammation. At T0, transforming growth factor β, connective tissue growth factor, and platelet-derived growth factor α mRNA were overexpressed in XLHN dogs compared with controls. Clusterin and TIMP1 transcripts were upregulated in later stages of the disease. Transforming growth factor β, connective tissue growth factor, and platelet-derived growth factor α should be considered as key players in the initial events of XHLN. Clusterin and TIMP1 appear to be more associated with the progression rather than initiation of tubulointerstitial damage in chronic renal disease.

Clinico-hemato-biochemical profile of dogs with liver cirrhosis

Aim:

The aim of this study was to determine the relevant tools in the diagnosis of liver cirrhosis in dogs.

Material and Methods:

A total of 140 dogs presented at Veterinary Teaching Hospital, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, showing clinical signs of hepatic insufficiency were subjected to clinico-hemato biochemical, urological, ultrasonographic (USG), and USG guided fine-needle biopsy examinations by standard methods. On the basis of these results, 6 dogs out of 140 dogs were found to be suffering from liver cirrhosis. Six clinically healthy dogs constituted the control group.

Results:

The dogs suffering from liver cirrhosis manifested inappetence, halitosis, abdominal distension, weight loss, melena, icterus, anemia, and neutrophilic leukocytosis with the left shift. Levels of hemoglobin, lymphocytes, packed cell volume, mean corpuscular volume, mean corpuscular Hb (MCH), and platelet count were significantly lower in liver cirrhosis group than control group while total leukocyte count, neutrophils, and MCH concentration were significantly higher. Glucose, total protein, albumin, A/G ratio, and fibrinogen were significantly lower, and creatinine, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, prothrombin time, and APTT were significantly higher than the control values. Ultrasound revealed diffuse increase in echogenicity with rounded and irregular liver margins. Cytological examination of the ascitic fluid and fine-needle aspiration biopsy of liver was not fruitful in the diagnosis of liver cirrhosis.

Conclusions:

Liver cirrhosis causes clinical and hemo-biochemical alterations, which require special consideration when treating diseased animals. USG, diffuse increase in echogenicity of liver, rounding and irregularity of liver margins and microhepatica were the consistent findings. It is suggested that USG along with hemo-biochemical alterations may be used as a diagnostic tool for liver cirrhosis in dogs.

Nitric oxide pathway-related gene alterations in inflammatory bowel disease

OBJECTIVE

To reveal specific gene activation in nitric oxide (NO)-related inflammation we studied differential gene expression in inflammatory bowel disease (IBD).

METHODS

Total RNA was isolated from 20 biopsies of inflamed mucosa from Crohn's disease (CD) and ulcerative colitis (UC) patients each as well as from six controls, labeled with (32)P-dCTP and hybridized to a human NO gene array. Significant genes were analyzed for functional gene interactions and heatmaps generated by hierarchical clustering. A selection of differentially expressed genes was further evaluated with immunohistochemical staining.

RESULTS

Significant gene expression differences were found for 19 genes in CD and 23 genes in UC compared to controls, both diseases with high expression of ICAM1 and IL-8. Correlation between microarray expression and corresponding protein expression was significant (r = 0.47, p = 0.002). Clustering analysis together with functional gene interaction analysis revealed clusters of coregulation and coexpression in CD and UC: transcripts involved in angiogenesis, inflammatory response mediated by the transcription factor hypoxia-inducible factor 1, and tissue fibrosis. Also, a fourth cluster with transcripts regulated by the transcription factor Sp1 was found in UC.

CONCLUSIONS

Expression analysis in CD and UC revealed disease-specific regulation of NO-related genes, which might be involved in perpetuating inflammatory disease activity in IBD.