I. Janus

Myocarditis in dogs: etiology, clinical and histopathological features (11 cases: 2007–2013)

BackgroundMyocarditis is a disease caused by numerous etiological factors and characterized by a non-specific course. The only method allowing for precise characterization of inflammatory changes is the histopathological examination of heart muscle specimens. The study was conducted on heart muscle preparations from 11 dogs with ante-mortem diagnosis of cardiac disease. Animals presented with a poor response to an applied treatment or had suspected sudden cardiac death. The heart specimens were taken post-mortem, preserved and stained with haematoxylin and eosin. Subsequently, the presence and intensity of changes, i.e. inflammatory infiltration, the amount of connective tissue and features of cardiomyocyte degeneration were estimated. The specimens from dogs suspected of having a myocarditis of bacteriological etiology underwent additional bacteriological and immunohistochemical examination.ResultsThe examination revealed an inflammatory infiltration of variable intensity combined with the degenerative changes in all dogs. There were vegetative and abnormal cystic forms of Borrelia burgdorferi sensu lato in 6 dogs. A Staphylococcus aureus infection was confirmed in one dog and an acute coronary syndrome with neutrophil infiltration was revealed in another one.ConclusionsAlthough the clinical pattern in patients with myocarditis is diverse, the definitive morphological diagnosis is made based on the histopathological examination. This examination can lead to a better understanding of the pathogenesis of the disease. To the best of our knowledge, this is the first description of myocarditis combined with the presence of spore forms of Borrelia burgdorferi sensu lato in the heart specimens of dogs.

Comparative analysis of markers of cell proliferation in canine mast cell tumours according to current classifications

The study aimed at immunohistochemical analysis of various markers of cell proliferation and comparison of the results with canine mast cell tumours grading systems according to the Patnaik and Kiupel. Tissue sections were stained using classical technique with haematoxylin and eosin, and immunohistochemical studies were performed with Ki-67, PCNA and MCM-3 antibodies. Additionally the mitotic index was assessed. Statistical analysis including rank correlation Spearmans and ANOVA Friedman analysis was performed. The significance was set at p<0.05. Expression of all examined antigens was detected. The results obtained allow concluding that there is a strong relationship between all the cell markers. However, due to the very strong response and positive reaction in the majority of tumours PCNA is not recommended as a prognostic indicator. Ki-67 and MCM-3 can be successfully used in the evaluation of canine mast cell tumours.

Surgical resection of peripheral odontogenic fibromas in African pygmy hedgehog (Atelerix albiventris): a case study.

BackgroundNeoplastic lesions of the mammary gland, lymph nodes, or oral cavity in African pygmy hedgehogs (Atelerix albiventris) are common in captive animals. Chemotherapy and radiotherapy protocols have not yet been established for the African pygmy hedgehog. Thus, surgical resection is the current treatment of choice in this species.Case presentationA 5-year-old male African pygmy hedgehog showed multiple erythematous, round small tumors located in the oral cavity, on both sides of maxilla. The treatment of choice was surgical resection of tumors using a surgical knife under general anesthesia. Excised neoplastic lesions were diagnosed as peripheral odontogenic fibroma by histopathology. Six months after surgery relapse of tumors in the oral cavity was not observed.ConclusionsThe treatment adopted in this case report is safe for the patient and provides the best solution for mild proliferative lesions of the oral cavity. To our knowledge this is the first report of surgical resection of oral tumors (peripheral odontogenic fibroma) in the African pygmy hedgehog.

A comparison of the histopathologic pattern of the left atrium in canine dilated cardiomyopathy and chronic mitral valve disease

BackgroundDilated cardiomyopathy (DCM) and chronic mitral valve disease (CMVD) in dogs are associated with heart chamber enlargement, also of the left atrium. DCM is often accompanied by rhythm disturbances (mainly atrial fibrillation or ventricular arrhythmias). In CMVD, arrhythmias are observed less frequently. It is still unclear whether left atrial enlargement in these diseases results from volume overload or if it is also connected with other factors (e.g. rhythm disturbances).This study was conducted on the left atrial myocardial specimens from 31 dogs, including those from 16 dogs with clinically diagnosed DCM and 15 dogs with CMVD. After fixation and staining (using haematoxylin-eosin and Masson-Goldner trichrome stain), the specimens underwent evaluation. Parenchymal changes (fibrosis, fatty infiltration, and vessel narrowing), degenerative changes (loss of striation, changes in cardiomyocyte structure, and abnormal cell nuclei) and the presence of inflammatory infiltrates were assessed.ResultsMore interstitial fibrosis (median 4 vs. 2.5 grid fields; p < 0.05) and less perivascular fibrosis (median score 1 vs. 2; p < 0.05) was observed in the DCM group compared to the CMVD group. Moreover, less distinct vessel narrowing was observed in the DCM group than in the CMVD group (median lumen area ratio 0.3 vs. 0.26 respectively; p < 0.05). Dogs with DCM showed more strongly defined degenerative changes than the CMVD dogs (median nuclei enlargement score 3 vs. 1, median loss of striation score 3 vs. 2 and median structural alterations score 3 vs. 2, respectively; p < 0.05).ConclusionThe obtained results indicate a different nature of changes occurring in the left atrial myocardium of dogs with DCM compared to dogs with mitral valve disease, including differences in vessel narrowing, cardiomyocyte degeneration and in the distribution of connective tissue.

Pathomorphological Changes of the Myocardium in Canine Dilated Cardiomyopathy (DCM)

Abstract The study was conducted on ventricular and atrial wall preparations from 11 dogs with clinically diagnosed dilated cardiomyopathy. After fixation, the specimens were stained with haematoxylin and eosin and Masson-Goldner trichrome technique. Parenchymal changes (fibrosis and fatty infiltration), vascular changes (congestion and coronary vessel wall hypertrophy), degenerative changes (loss of striation, changes in cardiomycyte and nuclei structure), and presence of inflammatory infiltrates (mononuclear and polynuclear) were estimated. Complex histological changes in both ventricular and atrial muscles were shown. It was not determined whether the processes occurring in the myocardium have a primary character, or are a consequence of developing heart failure. Such issues will be put under further and more detailed examination.

Cardiomyocyte marker expression in dogs with left atrial enlargement due to dilated cardiomyopathy or myxomatous mitral valve disease

INTRODUCTION Dilated cardiomyopathy (DCM) and myxomatous mitral valve disease (MMVD) are common heart conditions in dogs. They have different etiology and pathogenesis and although other studies focused on changes in the left ventricles of the affected hearts, the aim of our study was to assess the expressions of some intrinsic proteins in the enlarged left atria. MATERIAL AND METHODS We performed an immunohistochemical analysis of left atrial specimens obtained from 15 dogs with DCM, 35 dogs with MMVD and six control dogs. We assessed the expression of following proteins: SERCA1, SERCA2, sarcomeric actinin, smooth muscle actin, and dystrophin. RESULTS We noted a higher percentage of SERCA1-positive cells in the MMVD group and lower percentage of dystrophin-positive cells in the DCM group as compared to control group. The expression of other proteins was similar in the hearts of control dogs and dogs with heart diseases. CONCLUSIONS The observed changes in the expression patterns of some proteins in the atria of dogs with DCM and MMVD suggest that atrial enlargement relies not only on volume overload, but also alterations of the intrinsic proteins can contribute to the pathogenesis of dilated cardiomyopathy.

Atrioventricular valvular anomalies and their role in the etiopathogenesis of cardiorespiratory syndrome in farmed common foxes (Vulpes vulpes).

ABSTRACT Background: Cardiorespiratory syndrome of common foxes is associated with a mortality rate ranging from 2.1% to 20%. Objective: The aim of this study was to analyze the prevalence of cardiac abnormalities in common foxes (Vulpes vulpes) from Polish farms with a history of cardiorespiratory syndrome. Animals and methods: The prevalence of cardiac abnormalities in common foxes from a Polish farm with a history of cardiorespiratory syndrome was assessed as well as morphological examination of 60 heart specimens from clinically healthy animals. In addition, 38 foxes were examined echocardiographically and subjected to postmortem examination. Results: Atrioventricular valvular abnormalities were found in 57 out of the 98 (58%) analyzed hearts. The abnormalities of the mitral valve documented in more than 20% of the foxes in involved tendinous chords (completely lacking or shortened), papillary muscles and mitral cusps associated with both insufficiency and stenosis of the left atrioventricular orifice. Abnormalities of the tricuspid valve included significant shortening of the tendinous chords and thickening of the valve cusps with the impairment of their mobility. The results of the echocardiographic and postmortem examination were consistent in 79% of the cases. The specimens collected from animals with and without atrioventricular valvular anomalies did not differ significantly in terms of cardiomyocyte width, number of inflammatory cells, adipose tissue content and presence of polychromatic cardiomyocytes. Conclusion: Congenital atrioventricular valvular defects may be involved in the etiology of cardiorespiratory syndrome in common foxes, and echocardiography can be used as a measure of stocks health and a criterion for selection for mating.

Immunohistochemical analysis of metastasising hepatocellular carcinomas in dogs

In this study, the immunohistochemical features of primary hepatocellular carcinomas and their metastases in visceral organs, including the lungs, spleen and kidneys were examined using antibodies against carcino-embryonic antigen (CEA) cytokeratin (CK) 7 and 20, CD4, CD8, minichromosome maintenance protein 3 (MCM3), vimentin, and alpha 1 foetoprotein (AFP). In addition, Mallory’s connective tissue stain, van Gieson’s stain and Gomori methenamine silver stain were used. The study was performed on liver samples collected post mortem from five mixed-breed dogs aged 9–12 years. The tumours were classified according to the World Health Organization Classification of Tumours. Strong expression of MCM3 and AFP was found in the hepatic cancer cells and in the metastases to the lungs, spleen and kidneys. The primary tumours and metastatic foci did not react positively with the anti-CD4, anti-CD8, CEA, CK7 and CK20 antibodies. The connective tissue in the primary tumour and the metastases showed a positive reaction to vimentin. Canine hepatocellular carcinomas that metastasise are highly-malignant well-differentiated tumours that produce AFP and trace amounts of both carcinoembryonic antigen and cytokeratin. Therefore, the metastasis resembles the primary tumour and has a common phenotype and genotype with the primary tumour.

The immunohistochemical evaluation of selected markers in the left atrium of dogs with end-stage dilated cardiomyopathy and myxomatous mitral valve disease – a preliminary study

BackgroundDilated cardiomyopathy (DCM) and myxomatous mitral valve disease (MMVD) are the most common diseases noted in dogs. Although their pathogenesis varies, both include a significant enlargement of the left atrium.The study was carried out on left atrial specimens obtained from 56 dogs, including those from 34 dogs with clinically diagnosed MMVD, 15 dogs with DCM and 7 dogs without heart disease (control group). Dogs in the MMVD and the DCM groups presented with left atrial enlargement and stage D heart failure. The specimens underwent immunohistochemical examination using desmin, vimentin, periostin and caspase-3 antibodies.ResultsThere were alterations in the expression of the studied proteins in the study groups compared to the control group. The changes included: irregularity of desmin cross-striation and desmosomes, a higher amount of vimentin-positive cells, a change in the periostin expression pattern from cytoplasmic to extracellular, and a lower expression of caspase-3. The alterations were more pronounced in the DCM group than in the MMVD group.ConclusionsDuring heart failure, the pattern of desmin, vimentin, periostin and caspase-3 expression alters in the left atrium, regardless of the cause. The changes are more pronounced in dogs with DCM than in dogs with MMVD and similar left atrial enlargement, suggesting that volume overload may not be the only cause of myocardial changes in DCM.

Comparison of histopathological changes in atrial and ventricular specimens from dogs with dilated cardiomyopathy

COMPARISON OF HISTOPATHOLOGICAL CHANGES IN ATRIAL AND VENTRICULAR SPECIMENS FROM DOGS WITH DILATED CARDIOMYOPATHY I. Janus*, A. Noszczyk-Nowak y, M. Nowak*, M. KandeferGola*, R. Ciaputa*, D. Poradowski z, U. Pas1awska y and J.A. Madej* *Department of Pathology, Division of Pathomorphology and Veterinary Forensics, yDepartment of Internal Medicine and Clinics of Diseases of Horses, Dogs and Cats and zDepartment of Biochemistry, Pharmacology and Toxicology, Division of Pharmacology and Toxicology, University of Environmental and Life Sciences, Wroclaw, Poland Introduction: Dilated cardiomyopathy (DCM) is a disease of both man and animals involving myocardial changes causing heart failure. The alterations are present mostly in the left ventricular wall, but may also involve the right ventricular wall and the interventricular septum. Materials and Methods: The study was carried out on a group of six dogs (four doberman pinchers and two boxers) with clinical evidence of dilated cardiomyopathy. Specimens from both atria, both ventricles and the interventricular septum were stained with HE and MassoneGoldner’s trichrome. The assessment of presence and intensity of fibrous tissue, adipose tissue, inflammatory infiltrates, vascular changes and cardiomyocyte degenerative changes was made. Results: Complex histological changes involving both atrial and ventricular walls were noted. There was more fibrous tissue in the atria compared with the ventricles, but no other significant differences were found. Conclusions: Previous work has indicated that histopathological changes can be found not only in the left, but also in the right ventricle. We compared specimens from all heart chambers, showing that alterations also affect the atrial myocardium. The observed higher intensity of fibrous tissue in atria compared with ventricles may reflect the high susceptibility of dogs with DCM to supraventricular rhythm disturbances. At this point it is impossible to specify whether the alterations are an effect of myocardial cell primary remodelling or a cardiac response to progressive overload and heart failure.