Shelley J. Newman

Eicosapentaenoic Acid Prevents and Reverses Insulin Resistance in High-Fat Diet-Induced Obese Mice via Modulation of Adipose Tissue Inflammation

We investigated the effects of eicosapentaenoic acid (EPA) on prevention (P) and reversal (R) of high saturated-fat (HF) diet-induced obesity and glucose-insulin homeostasis. Male C57BL/6J mice were fed low-fat (LF; 10% energy from fat), HF (45% energy from fat), or a HF-EPA-P (45% energy from fat; 36 g/kg EPA) diet for 11 wk. A 4th group was initially fed HF for 6 wk followed by the HF-EPA-R diet for 5 wk. As expected, mice fed the HF diet developed obesity and glucose intolerance. In contrast, mice fed the HF-EPA-P diet maintained normal glucose tolerance despite weight gain compared with the LF group. Whereas the HF group developed hyperglycemia and hyperinsulinemia, both HF-EPA groups (P and R) exhibited normal glycemia and insulinemia. Further, plasma adiponectin concentration was lower in the HF group but was comparable in the LF and HF-EPA groups, suggesting a role of EPA in preventing and improving insulin resistance induced by HF feeding. Further analysis of adipose tissue adipokine levels and proteomic studies in cultured adipocytes indicated that dietary EPA supplementation of HF diets was associated with reduced adipose inflammation and lipogenesis and elevated markers of fatty acid oxidation. In C57BL/6J mice, EPA minimized saturated fat-induced insulin resistance and this is in part mediated by its effects on fatty acid oxidation and inflammation.

Localization of pancreatic inflammation and necrosis in dogs

Few studies of the prevalence of histologic lesions of the exocrine pancreas in dogs have been reported, and none of them systematically evaluate the localization of these lesions. The purpose of this study was to describe the anatomic localization of pancreatic inflammation, necrosis, and fibrosis in dogs presented for postmortem examination. Seventy-three pancreata from dogs presented for postmortem examination were evaluated and investigated for the presence of suppurative inflammation (SI), pancreatic necrosis (PN), and lymphocytic inflammation (LI). Sections that showed evidence of SI, PN, or LI also were evaluated for pancreatic fibrosis (F). The tendency for a preferred localization for SI, PN, and LI was evaluated by chi-square analysis. A total of 47 pancreata with histologic evidence of pancreatitis (SI, PN, or LI; F alone was not considered evidence of pancreatitis) were identified. Twenty-four (51.1%) had SI, 23 (48.9%) had PN, and 34 (72.3%) had LI. Of the 47 dogs with SI, PN, or LI, 28 (59.6%) had F. The distribution of SI, PN, and LI between the right and the left limb of the pancreas and among the 5 anatomic regions was random, based on a goodness-of-fit test. We conclude that pancreatic inflammation tends to occur in discrete areas within the pancreas rather than diffusely throughout the whole organ. These findings suggest that a single biopsy is insufficient to exclude subclinical pancreatitis and that there is no preferred site for pancreatic biopsy collection unless gross lesions are apparent.

Launching a Novel Preclinical Infrastructure: Comparative Oncology Trials Consortium Directed Therapeutic Targeting of TNFα to Cancer Vasculature

Background Under the direction and sponsorship of the National Cancer Institute, we report on the first pre-clinical trial of the Comparative Oncology Trials Consortium (COTC). The COTC is a novel infrastructure to integrate cancers that naturally develop in pet dogs into the development path of new human drugs. Trials are designed to address questions challenging in conventional preclinical models and early phase human trials. Large animal spontaneous cancer models can be a valuable addition to successful studies of cancer biology and novel therapeutic drug, imaging and device development. Methodology/Principal Findings Through this established infrastructure, the first trial of the COTC (COTC001) evaluated a targeted AAV-phage vector delivering tumor necrosis factor (RGD-A-TNF) to αV integrins on tumor endothelium. Trial progress and data was reviewed contemporaneously using a web-enabled electronic reporting system developed for the consortium. Dose-escalation in cohorts of 3 dogs (n = 24) determined an optimal safe dose (5×1012 transducing units intravenous) of RGD-A-TNF. This demonstrated selective targeting of tumor-associated vasculature and sparing of normal tissues assessed via serial biopsy of both tumor and normal tissue. Repetitive dosing in a cohort of 14 dogs, at the defined optimal dose, was well tolerated and led to objective tumor regression in two dogs (14%), stable disease in six (43%), and disease progression in six (43%) via Response Evaluation Criteria in Solid Tumors (RECIST). Conclusions/Significance The first study of the COTC has demonstrated the utility and efficiency of the established infrastructure to inform the development of new cancer drugs within large animal naturally occurring cancer models. The preclinical evaluation of RGD-A-TNF within this network provided valuable and necessary data to complete the design of first-in-man studies.

Marine Mammal Neoplasia: A Review

A review of the published literature indicates that marine mammal neoplasia includes the types and distributions of tumors seen in domestic species. A routine collection of samples from marine mammal species is hampered, and, hence, the literature is principally composed of reports from early whaling expeditions, captive zoo mammals, and epizootics that affect larger numbers of animals from a specific geographic location. The latter instances are most important, because many of these long-lived, free-ranging marine mammals may act as environmental sentinels for the health of the oceans. Examination of large numbers of mortalities reveals incidental proliferative and neoplastic conditions and, less commonly, identifies specific malignant cancers that can alter population dynamics. The best example of these is the presumptive herpesvirus-associated metastatic genital carcinomas found in California sea lions. Studies of tissues from St. Lawrence estuary beluga whales have demonstrated a high incidence of neoplasia and produced evidence that environmental contamination with high levels of polychlorinated biphenols and dichlorophenyl trichloroethane might be the cause. In addition, viruses are suspected to be the cause of gastric papillomas in belugas and cutaneous papillomas in Florida manatees and harbor porpoises. While experimental laboratory procedures can further elucidate mechanisms of neoplasia, continued pathologic examination of marine mammals will also be necessary to follow trends in wild populations.

Peripheral neuritis in psittacine birds with proventricular dilatation disease

Necropsies were performed on 14 psittacine birds of various species suspected to have proventricular dilatation disease (PDD). Eight of the birds exhibited neurological signs (seizures, ataxia, tremors and uncoordinated movements) and digestive tract signs (crop stasis, regurgitation, inappetance and presence of undigested food in the faeces). At necropsy, the birds had pectoral muscle atrophy, proventricular and ventricular distention, thinning of the gizzard wall, and duodenal dilation. In addition, five birds had a transparent fluid (0.2 to 1.0 ml) in the subarachnoidal space of the brain, and one bird had dilatation of the right ventricle of the heart. The histological lesions differed from earlier reports of PDD in that peripheral (sciatic, brachial and vagal) neuritis was seen in addition to myenteric ganglioneuritis, myocarditis, adrenalitis, myelitis and encephalitis.

Histologic assessment and grading of the exocrine pancreas in the dog.

Histologic grading schemes for canine inflammatory conditions are sparse, and in the case of the canine pancreas, have not been previously described. In a previous study, we determined that histologic lesions of the exocrine pancreas occurred much more frequently than gross lesions. The intention of the current study was to develop a histologic grading scheme for nonneoplastic lesions following extensive assessment of the exocrine pancreas from dogs presented for necropsy examination. The parameters of the proposed scheme include neutrophilic inflammation, lymphocytic inflammation, pancreatic necrosis, pancreatic fat necrosis, edema, fibrosis, atrophy, and hyperplastic nodules. In this case series, the most common lesion was pancreatic hyperplastic nodules (80.2%), followed by lymphocytic inflammation (52.5%), fibrosis (49.5%), atrophy (46.5%), neutrophilic inflammation (31.7%), pancreatic fat necrosis (25.7%), pancreatic necrosis (16.8%), and edema (9.9%). Only 8 of the 101 animals had no evidence of any of the lesions in any of the sections examined. Fibrosis, atrophy, and/or lymphocytic infiltration most commonly accompanied nodules. Neutrophilic inflammation, when present, was often associated with necrosis (pancreatic necrosis, pancreatic fat necrosis, or both) and occasionally with hyperplastic nodules. The utilization of a grading scheme for exocrine pancreatic lesions will be useful in advancing the classification of exocrine pancreatic disease in the dog, which may lead to multicenter studies of exocrine pancreatic disorders in the dog and in other species.

Aflatoxicosis in nine dogs after exposure to contaminated commercial dog food

The purpose of this study was to characterize light and electron microscopic findings from 9 dogs that had consumed aflatoxin-contaminated commercial dog food from recalled batches. Four dogs died and 5 were euthanized after signs of liver failure. Analysis of feed and liver samples confirmed exposure to aflatoxin. Of the 9 dogs, 8 had classic signs of liver failure, and 1 had signs of liver failure. Enlarged, pale yellow livers were seen macroscopically at necropsy in the dogs with subacute hepatopathy, and cirrhosis was noted in the dog with chronic hepatopathy. Histopathologic findings included hepatic lipidosis, portal fibroplasia, and biliary hyperplasia, which supported a diagnosis of subacute toxic hepatopathy in the 8 symptomatic animals. Marked lobular atrophy, bridging portal fibrosis, and regenerative hepatocellular nodules characterized the dog with chronic hepatopathy. Electron microscopy revealed marked hepatocellular lipid vacuolation and early fibroplasia in the dogs with acute hepatopathy and marked fibrosis and regeneration in the dog with chronic hepatopathy. Analysis of feed for aflatoxin consistently revealed high levels of aflatoxin B1 (range of 223–579 ppb), and hepatic tissue contained elevated levels of aflatoxin B1metabolite M1 (0.6–4.4 ppb). Although dogs are not commonly affected by aflatoxicosis, they are highly susceptible and can present with classic signs of acute or chronic hepatopathy. Characteristic gross, histologic, and electron microscopic changes help pathologists determine a presumptive toxic insult. Detecting aflatoxins or their metabolites in feed or liver specimens can help confirm the diagnosis of aflatoxicosis.

Multiple congenital anomalies in a calf

A 4-hour-old mixed-breed black heifer calf produced fromin vitro fertilization and born via Caesarian section 6 daysprior to the anticipated due date was euthanized because ofmultiple obvious congenital anomalies and an inability tostand. The number of congenital anomalies was remarkableand included anal and vulvar atresia, hypoplastic clitoral tis-sue, cervical block vertebrae, anotia, brachygnathia inferior,secondary cleft palate, calvarial doming with hydrocephalusand stenosis of the Sylvian aqueduct, high ventricular septaldefect, rectovaginal fistula, and dermal hamartomas.Few previous reports of congenital anomalies in calveshave documented the number and the severity of those seenin this calf. Because development of tissues and organs isinterdependent, it is not uncommon for more than 1 anomalyto appear in an animal. In this calf, several rarely reportedanomalies, such as anotia, vulvar atresia, and dermal ham-artomas, were evident; these anomalies have not been pre-viously documented in cattle.An oocyst from an apparently healthy slaughterhouse cowwas fertilized with sperm from a transgenic bull and implant-ed in a 16-month-old recipient heifer on day 8 of embryodevelopment. Gestation proceeded without any clinical evi-dence of difficulty. The dam was vaccinated

Canine Hepatic Neuroendocrine Carcinoma: An Immunohistochemical and Electron Microscopic Study

Ten dogs with neuroendocrine carcinoma of the liver were selected for inclusion in the study. Clinical signs were anorexia (7), vomiting (5), polydipsia/polyuria (3), icterus (2), lethargy (2), weight loss (2), paresis (1), ataxia (1), weakness (1), collapse (1), and urinary tract infection (1). Hematologic and biochemical abnormalities included anemia (2/8), leukocytosis (4/8), high liver enzyme activity (serum alkaline phosphatase, 7/9; alanine transaminase, 7/9; aspartate transaminase, 8/9), and high total bilirubin (6/9). Grossly, the tumors were diffuse, involving all liver lobes in six dogs, and two dogs had various-sized nodules in addition to diffuse involvement. Histologically, there were eight tumors with solid or trabecular pattern (group A), one tumor with cords or rows of neoplastic cells (group B), and one tumor with multiple rosette-like structures (group C). immunohistochemical studies revealed that all 10 neoplasms were positive for at least one of the endocrine markers used: neuron-specific enolase (NSE; 8/10), synaptophysin (5/10), and chromogranin-A (3/10). A panel of NSE, chromagranin-A, and synaptophysin detected 100% of the tumors in our series. Electron microscopy confirmed the diagnosis by the presence of intracytoplasmic neurosecretory granules in the two examined cases. our results show that neuroendocrine markers commonly used in humans can be used for the diagnosis of hepatic neuroendocrine carcinoma in dogs, preferably a panel of synaptophysin, chromagranin-A, and NSE because chromogranin-A alone is not as useful in dogs as in humans.

Specificity of a canine pancreas-specific lipase assay for diagnosing pancreatitis in dogs without clinical or histologic evidence of the disease

OBJECTIVE To evaluate the specificity of a canine pancreas-specific lipase (cPSL) assay for diagnosing pancreatitis in dogs without clinical or histologic evidence of the disease. ANIMALS 20 dogs from another study with macroscopic evidence of pancreatitis and 44 dogs surrendered for euthanasia or expected to die. PROCEDURES Prior to death, physical examination of each dog was performed and blood samples were collected for serum biochemical, serum cPSL, and hematologic analyses. After death, the pancreas was removed, sectioned in 1- to 2-cm slices, and evaluated by a pathologist. Dogs were classified by whether they had clinical or macroscopic pancreatitis. Each pancreatic section was histologically examined, and mean cumulative scores (MCSs) were assigned for 8 histologic characteristics. For each characteristic, comparisons were made between dogs with and without pancreatitis to establish histologic criteria for lack of evidence of pancreatitis. RESULTS For all histologic characteristics except lymphocytic infiltration, the median MCS differed significantly between dogs with and without pancreatitis. Dogs were categorized as having no histologic evidence of pancreatitis when the MCSs for neutrophilic infiltration, pancreatic necrosis, peripancreatic fat necrosis, and edema were 0.0. On the basis of these criteria, 40 dogs were classified as having no evidence of pancreatitis. The cPSL concentration was within reference limits in 38 of these 40 dogs and was less than the cutoff value for diagnosing pancreatitis (400 μg/L) in 39 of the 40 dogs, resulting in a specificity of 97.5% (95% confidence interval, 86.8% to 99.9%). CONCLUSIONS AND CLINICAL RELEVANCE The cutoff cPSL value used in this study may be useful for diagnosing pancreatitis in dogs with a lack of histologic lesions consistent with pancreatitis and for which pancreatitis is not considered a major differential diagnosis.