Veterinary Pathology最新文献

Pigment-containing and light-reflecting cell neoplasms, generically termed chromatophoromas, affect fish, reptiles, and amphibians. Chromatophoromas of light-reflecting cells are named iridophoromas. In this study, we aimed to describe the gross, histologic, and ultrastructural findings of 71 cases of iridophoromas in farmed Siamese fighting fish (Betta splendens). Macroscopically, iridophoromas appeared as whitish, gray, or black friable masses or plaques in the fin, trunk/tail, or head of the fish. Forty-five tumors (63%) were malignant and invaded the adjacent skeletal muscle and/or metastasized to other organs, whereas 26 (37%) tumors were restricted only to the skin, but due to the cytologic similarity to the malignant counterpart, we were not able to classify them as malignant or benign. Sixty-five (91%) tumors were classified as iridophoromas, whereas 6 (8%) were diagnosed as mixed chromatophoromas. Despite immunolabeling for PNL-2, melan A, or S-100 failing to demonstrate antigen expression, ultrastructural analysis identified light-reflecting neoplastic cells, unequivocally confirming iridophoromas as the predominant tumor. The high incidence of iridophoromas in Siamese fighting fish from the same breeding facility, coupled with a higher occurrence in royal blue and fancy copper color patterns and in young males, suggests a potential genetic/hereditary factor in the tumorigenesis of these neoplasms.

This study aims to provide an in-depth examination of the histological changes that occur during the repair of untreated bone fractures in avian species, correlating these microscopic alterations with gross anatomical characteristics observed during different tissue repair phases. A total of 93 bone fractures from different wild birds were analyzed and classified based on temporality (acute, subacute, and chronic) according to the color changes of the hematoma and morphology (open or closed; simple, comminuted, or greenstick fractures). From a microscopic standpoint, a strong correlation was observed between the temporal progression observed macroscopically and the histological changes evident in each temporal category. Microscopic variations were found to depend on the nature of the fracture. Lesional patterns directly related to the macroscopic appearance of the fracture were established. Acute fractures exhibited extensive hematomas and an intense inflammatory response; subacute fractures showed immature granulation tissue and early signs of soft callus formation; and finally, chronic fractures were characterized by prominent soft calluses and hard calluses in different stages of development. The possible factors influencing each phase of the healing process, such as the characteristics of the type of fracture, the stability of the fracture site, bacterial contamination, the chronicity of the fracture, and the potential differences in the progression of histological changes between different animal species, are discussed. This association may be of clinical utility in decision-making for the treatment and prognosis of bone fractures in birds.

Splenic masses are common in dogs and vary dramatically in their clinical behavior. Clinically, and even with histology, it can be challenging to differentiate between benign and malignant splenic masses. Hemangiosarcoma (HSA), the most common malignancy of the spleen, is a very aggressive tumor with a poor prognosis. We hypothesize that microRNAs (miRNAs) in mass tissue and serum can differentiate between HSA and other splenic masses. Fifty-nine miRNAs were investigated by reverse-transcription followed by real-time quantitative polymerase chain reaction (RT-qPCR) in serum and/or tissue from dogs with HSAs (serum n = 24 and tissue n = 17; postsplenectomy serum n = 11), lymphomas (serum n = 8 and tissue n = 11), nonangiomatous nonlymphomatous sarcomas (serum n = 6 and tissue n = 10), histiocytic sarcomas (tissue n = 4), benign splenic masses (myelolipomas, nodular hyperplasia, and hematomas; total serum n = 21 and total tissue n = 35), and normal dogs (serum n = 14 and tissue n = 7). Numerous miRNAs were differentially expressed in serum and tissue of HSA cases compared to those with other splenic masses or normal spleens. In serum, our 5-miRNA model (miR-135a-5p, miR-10a, miR-450b, miR-152-3p, and miR-126-5p) accurately classified 100% (24/24) of dogs with HSA from normal dogs and those with a benign splenic mass (recall = 1 for HSA). The overall accuracy of the model was 86%. In HSA and benign splenic mass tissues, our 3-miRNA model (miR-126-5p, miR-502-3p, and miR-452-5p) accurately classified 96% of the cases. This study demonstrates the utility of miRNA models in serum and tissue for screening and diagnosis of HSA in dogs. Future studies include the evaluation of prospective and prediagnosis serum samples.

Papillomas, many of which are virally induced, are common proliferative cutaneous and mucocutaneous lesions in multiple species, exhibiting characteristic histologic cytopathic changes that distinguish them from nonviral squamous papillomas. A single case report of a novel papillomavirus, Ursus maritimus papillomavirus-type 1, in a polar bear has been reported without investigation into any association between this virus and papilloma formation. We identified papillomas in 3 polar bears. All 3 cases had pedunculated masses consistent with papillomas (i.e., proliferative epithelium forming papillary projections on a fibrovascular stalk); case 1 also exhibited koilocytosis (cytopathic change), consistent with a viral papilloma. Polymerase chain reaction (PCR) using primers that can amplify a diversity of papillomaviruses followed by amplicon sequencing yielded a novel papillomavirus sequence in case 1, which shared <70% nucleotide identity to any known papillomavirus type, indicative of a putatively novel papillomavirus. In situ hybridization (ISH) of case 1 demonstrated viral nucleic acid within proliferative cells and not within the adjacent normal skin, suggesting the virus was the causative agent of this papilloma. The squamous papillomas in cases 2 and 3 were negative for papillomavirus by both PCR and ISH. These findings support our hypothesis that cytopathic effect is associated with the presence of papillomavirus in polar bears, while the lack of histologic cytopathic change may predict nonviral pathogenesis. Further sequencing of the putatively novel viral genome will benefit research and conservation efforts of polar bears.

Malignant catarrhal fever (MCF) is an often fatal, sporadic gammaherpesvirus-induced disease of ruminants with global relevance. Ovine gammaherpesvirus-2 (OvHV-2), with sheep as its reservoir host, is a major cause of MCF in susceptible species. Despite extensive research on the molecular aspects of the disease, its pathogenesis is not yet fully understood. The present study re-established the Syrian golden hamster (Mesocricetus auratus) as an amenable animal model of MCF and applied complementary in situ approaches to confirm recent findings in natural disease that could shed new light on pathogenic aspects of MCF. These showed that systemic OvHV-2 infection is associated with T-cell and macrophage-dominated mononuclear infiltrates and vasculitis in various organs. Both T-cells and monocytes/macrophages harbor the virus, and infected leukocytes are abundant in the infiltrates. The results also indicate that OvHV-2 has a broader target cell spectrum, including vascular endothelial cells and selected squamous epithelia. The former supports the interpretation that the inflammatory processes develop due to circulating, activated, infected T-cells and monocytes that home to tissues and emigrate from vessels prone to leukocyte emigration, possibly with direct interaction between virus-infected leukocytes and endothelial cells. The latter supports the hypothesis of graft versus host disease scenario, without viral cytopathic effect on epithelial cells but infiltration of the mucosa by infected T-cells and macrophages. The disease processes are accompanied by evidence of expansion of the T-cell compartments and the monocyte/macrophage pool in lymphatic tissues and bone marrow.

Liver-type fatty acid-binding protein (L-FABP) is expressed by several tissues, plays a role in fatty acid metabolism, and has antioxidant effects. Its renal expression is upregulated by stress. Urinary L-FABP (uL-FABP) is a promising kidney biomarker in people for detection of early acute and chronic kidney disease (CKD) and as a marker for progression in patients with glomerulonephritis. However, data on canine uL-FABP are currently limited. This prospective study was designed to examine canine tissue expression of L-FABP and to validate an ELISA to quantify uL-FABP in older dogs with or without early signs of CKD. Tissues of 4 recently euthanized dogs and 117 urine samples of 73 client-owned older dogs undergoing health screening were evaluated in the study. Immunohistochemistry was performed on kidney and liver tissues. Analytical validation of a commercially available ELISA for measurement of L-FABP in canine urine was performed (limit of detection, imprecision, specificity). The ELISA was used to measure L-FABP in stored urine samples from a cohort of older dogs. Dogs were found to express L-FABP, mostly in proximal tubular epithelial cells and in the periportal hepatocytes of the liver. Assay validation revealed poor sensitivity and imprecision for measurement of canine uL-FABP. Of the 117 urine samples analyzed, 98 were below the limit of detection (LOD; 7.30 ng/mL) and a further 5 were below the limit of quantification (LOQ; 16.20 ng/mL). The proximal tubules of dog kidneys express L-FABP, but the value of uL-FABP as tubular marker in older dogs warrants further study.

Equine spinal neurodegenerative conditions are frequently encountered in sport and racing horses and may be career-ending diagnoses. To further define the spatial transcriptomic landscape of equine dorsal root ganglia (DRG) in healthy adult horses, we investigated gene expression differences in distinct DRG regions using the GeoMx Digital Spatial Profiling from NanoString. Four human cell markers demonstrated high fidelity for equine cells; microtubule-associated protein 2 (MAP2), myelin basic protein (MBP), allograft inflammatory 104 factor 1/ionized calcium-binding adaptor molecule 1 (IBA1/AIF1), and Syto83 nuclear marker. Geometric regions of interest were then selected as MBP-rich, IBA1-high, and IBA1-low, and gene expression was compared. Experimental validation was achieved, with genes involved in myelination enriched in MBP-rich regions, and the identification of glia-specific genes enriched in IBA1-high regions. Thus, spatial transcriptomics with human cell markers was successful in equine DRG and can now be applied to determine cell-specific transcriptional changes during disease states.