Veterinary Pathology最新文献

The kidney plays an important role in iron homeostasis and mesangial cells (MCs) are phagocytic cells important for glomerular homeostasis. Sickle hemoglobin (HbS) modulators are promising clinical candidates for treatment of sickle cell disease. Although they prevent disease pathophysiology of HbS polymerization and red blood cell (RBC) sickling by increasing hemoglobin oxygen affinity, higher oxygen affinity can also cause transient tissue hypoxia with compensatory increases in erythropoiesis and subsequent increases in RBC turnover. CD-1 mice treated with an HbS modulator for 2 weeks developed higher RBC mass, increased erythropoiesis, and, by 1 month, deposition of intracellular pigments in renal tubular and parietal epithelium. In addition, in mice treated for 26 weeks, pigment was observed in MCs, which was accompanied by glomerular cell aggregates (MC hypercellularity) and tubulo-interstitial inflammation. The pigment was confirmed by Perl's iron staining and transmission electron microscopy (TEM) to be iron-containing proteins. Glomerular cell aggregates were confirmed to be MCs by TEM, and Ki-67 immunolabeling suggested that MC hypercellularity was due to proliferation. Collectively, these findings, along with iron-containing proteins in livers and spleens, suggested that iron overload secondary to increased RBC turnover led to increased renal iron reabsorption. While both MC hypercellularity and tubulo-interstitial inflammation were thought to be responses to long-term accumulation of iron, the former was considered a homeostatic response to eliminate iron, and maintain glomerular structure and function, while the latter was more consistent with an iron-catalyzed oxidative stress response. To our knowledge, this is the first report of MC hypercellularity in a preclinical toxicity study.

Neoplasms are only sporadically reported in New World primates and rarely in owl monkeys (Aotus spp.), specifically. Previous reports of neoplasms in owl monkeys are primarily restricted to lymphoma induced by Herpesvirus saimiri infection, although other tumors in the central nervous, genitourinary, gastrointestinal, and endocrine systems have been sporadically reported. Herein, we describe 3 previously unreported neoplasms in owl monkeys (Aotus nancymaae) including a pericardial mesothelioma in a 6-year-old male, a nephroblastoma in a 2-year-old male, and a cervical neoplasm with characteristics of an epithelioid trophoblastic tumor in a 4-year-old female, all occurring in the same closed breeding colony at a research facility in central Texas. Reporting of spontaneously occurring neoplasms in research colony populations is important for identifying potential animal models of human diseases and for improving colony management and species health.

Progressive neurologic signs without a known underlying etiology have been observed in managed gibbon populations housed at institutions in North America. In 2018, the Gibbon Species Survival Plan initiated a veterinary survey to evaluate clinical histories among gibbons displaying neurologic signs. The clinical results of this survey as well as the results of a centralized histologic review of brain samples from 5 species of managed gibbons displaying neurologic signs are outlined here. Reported neurologic deficits in gibbons surveyed included tremors (12/12, 100%), ataxia/incoordination (11/12, 92%), fine motor skill deficits (11/12, 92%), weakness (10/12, 83%), and mentation deficits (7/12, 58%). Gross lesions were not identified in the brain. However, in affected animals, histology revealed infarctive lesions in the cerebrocortical (14/15, 93% of animals) and cerebellar (10/15, 67% of animals) gray/white matter. Lesions were absent in the thalamus, mesencephalon, and brainstem. Lesions were typified by areas of parenchymal loss, perivascular foamy macrophage accumulation, and extensive gliosis dominated by gemistocytic astrocytes. In all affected animals, vessels located in the center of the lesions had increased tortuosity with loss of medial distinction, variable medial hyperplasia, and multifocal medial vacuolation that was accentuated by Masson's trichrome staining. Thrombotic lesions were not identified, and amyloid was not identified by Congo red staining. Ionized calcium-binding adaptor molecule 1 (IBA1) immunohistochemistry revealed extensive macrophage infiltration, even in areas in which lesions were not identified on histologic examination. This study reveals a pattern of small-vessel disease among gibbons displaying neurologic signs, and the resulting clinical syndrome is here termed "gibbon infarctive encephalopathy."

High mortality in bobwhite quail chicks (Colinus virginianus) (35%-85%) was reported from a grower flock in Iowa during July and August of 2022. Two diagnostic submissions of dead, 3-day-old quail chicks were received. Postmortem examination revealed multifocal, pinpoint, pale tan foci in the liver of all birds. Histologic examination revealed moderate to severe, acute, multifocal, random necrotizing hepatitis with multinucleated cells and dystrophic mineralization. Metagenomic sequencing of liver detected orthoreovirus. A high level of avian reovirus (ARV) RNA was identified by real-time reverse transcriptase-PCR. ARV was successfully isolated from liver and lung on the Leghorn male hepatoma cell line. In addition, electron microscopy revealed orthoreovirus viral particles and virus factories in the formalin-fixed livers and viral-infected cell culture. This case highlights ARV as a potential cause of hepatitis in quail chicks and should be considered in the differential diagnosis.

The European hedgehog (Erinaceus europaeus) is a protected species of conservation concern in the UK. In recent years, there have been multiple incidents of fatal encephalitis in captive hedgehogs in wildlife rescue centers associated with the molecular detection of a hedgehog arterivirus (HhAV-1). However, it remains unclear whether the virus is the causative agent of the central nervous system (CNS) lesions. In a retrospective investigation using postmortem material from 7 captive hedgehogs with neurological disease, and a single hedgehog with previously identified meningoencephalitis, histologic examination was conducted in tandem with viral RNA in situ hybridization (ISH) to appraise tissue distribution of HhAV-1 and the colocalization with histologic lesions. ISH revealed multicellular tropism of HhAV-1 involving monocyte-macrophage and vascular endothelial cells, with viral RNA detected in multiple organs, likely due to endotheliotropism and viremia. In the CNS, encephalomyelitis was mild whilst viral RNA was abundant and widely distributed, particularly in the microglial population and localized to areas with glial nodules. Splenic lymphoid depletion was generally mild but was moderate to severe in 2 septicemic animals. Brain samples from 13 control hedgehogs, found dead in the wild due to predation/trauma, were also screened for HhAV-1, of which 8 tested positive by real-time reverse transcription polymerase chain reaction (RT-PCR) with a low viral load. No CNS lesions or ISH labeling was observed in 2 of these control hedgehogs that could be examined histologically. Combined, these findings indicate that HhAV-1 infections in captive hedgehogs in English wildlife rescue centers may be associated with histopathologic alterations and clinical neurological disease.

Soft tissue sarcomas (STSs) are conventionally viewed as poorly immunogenic tumors; however, some human STSs have recently been reported to elicit an immune response, thus representing potential candidates for immunotherapy. Data regarding immune cell infiltrates in canine STSs are limited and reported without tumor-type stratification. The aim of this study was to retrospectively assess tumor-infiltrating lymphocytes (TILs) in canine STSs of 5 different histotypes. Eighty-seven canine STSs were collected: 22 perivascular wall tumors (PWTs), 19 liposarcomas, 17 fibrosarcomas, 16 myxosarcomas, and 13 leiomyosarcomas. The tumors were graded and immunolabeled for CD3, CD20, and FoxP3, and slides were scanned. T-cell, B-cell, Treg, and total TIL densities were quantified with QuPath software and expressed as cells/mm². The B/T-cells ratio and Treg/T-cell proportions were calculated. Total TIL densities were higher in PWTs and myxosarcomas (median = 225 and 303, respectively). PWTs had higher T-cell density but lower Treg proportion (median = 152 and 7.6% respectively). Myxosarcomas had higher Treg densities and B/T-cell ratios (median = 24.4 and 1.57, respectively). No association with grade was found among STSs as a group. In myxosarcomas, higher grade was significantly associated with higher total TILs, and CD20+ and FoxP3+ cell densities (p < .05). The results suggest that PWTs and myxosarcomas may represent the most immunogenic STS types. Myxosarcomas elicit a B-cell and Treg-rich immune response; PWTs stimulate a T-cell-rich and Treg-poor reaction. The immune system response may contribute to the more aggressive behavior of myxosarcomas and the more indolent course of PWTs.