Jung-Hyang Sur

Retrospective Study of Melamine/Cyanuric Acid-Induced Renal Failure in Dogs in Korea between 2003 and 2004

In early 2007, American pet food ingredients leading to nephrotoxic renal failure of dogs and cats raised serious concerns about the safety of pet foods. Major pet food companies recalled more than 1,000 commercial pet foods in consideration of pet safety. A similar pet food-associated outbreak of nephrotoxic renal failure occurred in Asia, in late 2003 and 2004, resulting in a similar extensive pet food recall. At that time, contamination of ingredients with a nephrotoxin-producing fungus at a pet food production facility was suspected. However, toxicologic evidence to substantiate a mycotoxicosis was lacking. Moreover, the renal lesions were not typical of those reported with fungal nephrotoxins. During 2003 and 2004, 14 dogs were presented to the Veterinary Medical Teaching Hospital of Konkuk University, Seoul, Korea, with renal failure and distinctive renal pathologic findings. Grossly, the kidneys were greenish in color with greenish uroliths in the renal pelvis or bladder. Histologically, characteristic crystals with pinwheel radiating striations were present in distal tubular segments. Toxicologic analysis identified melamine, cyanuric acid, and ammelide in deparaffinized formalin-fixed kidney samples.

Development of an improved canine model of percutaneous spinal cord compression injury by balloon catheter

We developed a minimally invasive canine model of spinal cord injury (SCI). A balloon catheter was inserted into the epidural space via the lumbosacral space, and inflated between L2 and L3 for 30 or 60 min under fluoroscopic guidance. Motor function after SCI was assessed using modified Tarlov scale. All seven dogs showed complete paraplegia after the procedure, neurological problems were evident and the modified Tarlov scores remained at zero after the SCI procedure; no improvement in clinical signs was observed. The dogs underwent 3T MR imaging at 3 days and 1 year after SCI. Histopathologic examinations were conducted at 2 weeks, 12 weeks and 1 year after SCI. In the present study, we described an animal model of minimally invasive spinal cord injury using a balloon catheter without laminectomy under fluoroscopic guidance. And, this percutaneous spinal cord compression injury model has many potential applications. The described percutaneous spinal cord compression injury model offers a new means of administering SCI and has many potential applications.

Analysis of a new histological and molecular-based classification of canine mammary neoplasia.

Canine mammary tumors (CMTs) are morphologically and biologically heterogeneous, prompting several attempts to classify such tumors on the basis of their histopathological characteristics. Recently, molecular-based analysis methods borrowed from human breast cancer research have also been applied to the classification of CMTs. In this study, canine mammary neoplasms (n = 648) occurring in Korea from 2008 to 2011 were analyzed according to the histological classification and grading system proposed by Goldschmidt et al. Furthermore, randomly selected mammary carcinomas (n = 159) were classified according to the molecular subtype using immunohistochemical characteristics. Canine mammary neoplasia accounted for 52.6% (648/1250) of the tumors in female dogs, and 51.7% (340/648) of these were malignant. All of the carcinoma-anaplastic subtypes were grade III tumors (5/5, 100%), while most of the carcinoma-tubular subtypes (15/18, 83.3%) and carcinoma arising in a complex adenoma/mixed-tumor subtype (115/135, 85.2%) were grade I tumors. Tumor cell invasion into lymphatic vessels was most common in the comedocarcinoma, carcinoma-anaplastic, and inflammatory carcinoma subtypes. The most frequently occurring molecular subtype (70/159, 44%) was luminal A. However, the basal-like subtype was the most malignant and was frequently associated with grade III tumors and lymphatic invasion. The carcinoma-solid subtypes were also often of the basal-like subtype. Reclassification of CMTs using the newly proposed histopathological classification system and molecular subtyping could aid in determining the prognosis and the most suitable anticancer treatment for each case.

Identification of triple-negative and basal-like canine mammary carcinomas using four basal markers.

Molecular-based classification of canine mammary carcinomas (CMCs) has been a recent research focus. In human breast cancer, triple-negative and basal-like phenotypes are distinct molecular subgroups that are known for their poor prognosis, but these tumours are not yet well defined in the dog. The aim of this study was to determine whether CMCs include triple-negative and basal-like phenotypes by immunohistochemical assessment of expression of the oestrogen receptor (OR), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and four basal markers, cytokeratin (CK) 14, CK5/6, p63 and the epidermal growth factor receptor (EGFR). In this study of 241 CMCs, 45 triple-negative tumours (OR(-), PR(-) and HER2(-)) were identified and this phenotype was associated with an unfavourable prognosis. In these tumours, the expression of CK14, CK5/6 and EGFR was related to clinicopathological parameters, while the expression of p63 was not relevant. The majority of the triple-negative tumours were of the basal-like phenotype, given that 75.6% of them expressed more than two basal markers. However, three of the basal markers were not uniformly expressed; therefore, the proportion of the basal-like phenotype was altered on the basis of the selection of the markers. Although both triple-negative and basal-like phenotypes are distinct entities in CMC, further study is needed to differentiate one from the other.

Expression of HER-2 and nuclear localization of HER-3 protein in canine mammary tumors: Histopathological and immunohistochemical study

HER-2 and HER-3 are transmembrane receptor proteins that are considered to be important but poorly understood biomarkers in canine tumors. In this study, the expression and the localization of HER-2 and HER-3 were evaluated immunohistochemically in canine mammary tumors (n=64; 12 benign, 52 malignant). HER-2 overexpression was identified in 2/12 (16.7%) benign and in 18/51 (35.3%) malignant cases. HER-3 was expressed in a non-nuclear localization in 11/12 (91.7%) benign and 18/52 (34.6%) malignant tumors. In contrast, HER-3 was expressed in the nucleus of neoplastic cells in 0/12 (0%) benign and 22/52 (42.3%) malignant tumors. Nuclear HER-3 expression was higher in neoplastic epithelial cells compared to myoepithelial cells, and positively correlated with high histological grade and lymphatic vessel invasion. These results suggest that nuclear HER-3 expression is significantly associated with tumor progression and metastasis and may serve as a useful prognostic biomarker in canine malignant mammary tumors.

Histopathological and immunohistochemical comparison of the brain of human patients with Alzheimer's disease and the brain of aged dogs with cognitive dysfunction.

Alzheimers disease (AD) is the most common progressive form of dementia in aged people. Microscopical changes in the brains of AD patients include the formation of senile plaques (SPs), neurofibrillary tangles (NFTs) and granulovacuolar degeneration and the deposition of amyloid-beta (Aβ). Aged dogs are known to suffer from cognitive dysfunction and this state is associated with deposition of Aβ in the brain. The aim of the present study was to investigate tau phosphorylation of neurons and astrocytes in the brain of aged dogs with progressive cognitive impairment. Changes in the brain of aged dogs with cognitive dysfunction were compared with those in the brain of patients with AD of Braak stage V. Immunohistochemically, Aβ deposition, phosphorylated tau Ser396 (p-tau Ser396) and ubiquitin were observed in the parietal cortex and hippocampus of aged dogs with cognitive dysfunction. Astrocytes with expression of p-tau Ser396 and neurons with co-localization of p-tau Ser396 and ubiquitin were observed. Expression of p-tau Ser396 and accumulation of ubiquitin were significantly increased in the parietal cortex and dorsal part of the hippocampus of the brain of aged dogs when compared with expression of these molecules in human AD.

Lymphocyte infiltration, expression of interleukin (IL)-1, IL-6 and expression of mutated breast cancer susceptibility gene-1 correlate with malignancy of canine mammary tumours.

Malignant tumours are often associated with a relatively high number of tumour-infiltrating lymphocytes (TILs) and associated local cytokine production and these factors are thought to play a role in tumour progression. These aspects of tumour microenvironment have not been studied in canine mammary gland tumours (MGTs). The present study investigates TILs and the presence of related cytokines, as well as the expression of breast cancer susceptibility gene-1 (BRCA1), in canine MGTs. Immunohistochemistry, immunoblotting and reverse transcriptase-polymerase chain reaction were performed to evaluate these parameters. Three times as many T lymphocytes as B cells infiltrated canine MGTs. A correlation was found between expression of interleukin (IL)-1 and IL-6 and metastasis. There was an association between the expression of TILs, cytokines and mutation of BRCA1, suggesting that all of these factors may play a role in tumour progression.

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.

Correlation of Foxp3 positive regulatory T cells with prognostic factors in canine mammary carcinomas.

Regulatory T cells (Treg) cells play a crucial role in tumor progression by suppressing anti-tumor immunity, but are not well-documented in veterinary oncology. To identify the characteristics of Treg cells in tumor microenvironments, the numbers of Treg cells were analyzed and compared with histological prognostic factors and molecular biomarkers in canine mammary carcinoma (MC) tissues (n=37). Abundant Treg cells were associated with high histological grade and lymphatic invasion. The numbers of Treg cells infiltrating intratumoral areas markedly increased in tumors with poor prognostic factors, such as high histological grade, lymphatic invasion, and necrosis. These findings suggest that Treg cells play a role in canine MC progression. Furthermore, Treg cell numbers in intratumoral compartments may provide a potential prognostic factor when assessing canine MCs, which may in turn lead to the development of new immunologic therapeutics.

CDX-2 and HER-3 Expression in Canine Gastric and Colorectal Adenocarcinomas

CDX-2 is used as a specific cell marker for human intestinal adenocarcinoma. In human studies, HER-3 overexpression predicts poor survival for patients with various cancers including gastric cancer. Gastrointestinal adenocarcinoma is less common in dogs than in man and the expression of immunological markers by the canine tumours has not yet been extensively studied. CDX-2 and HER-3 expression was determined in 18 canine gastrointestinal adenocarcinomas: 13 were of colorectal origin and five were of gastric origin. CDX-2 expression was predominantly observed in the nuclei of normal colonic epithelium and in neoplastic epithelium and neoplastic gastric epithelial cells that which had metastasized to the gastric lymph node. CDX-2 was expressed in 11 of 13 (84.6%) colorectal adenocarcinomas and in all five (100%) gastric adenocarcinomas. HER-3 was consistently expressed in the cytoplasm of neoplastic epithelial cells. HER-3 expression was detected in 12 of 13 (92.3%) colorectal and in all five (100%) gastric adenocarcinomas. CDX-2 and HER-3 may be useful markers for canine gastrointestinal adenocarcinoma.