Veterinary Pathology最新文献

"Pix" is one of the most common skin defects that reduce the quality of crocodilian leather. The name is derived from their resemblance to pit marks made by an ice pick. Histologically, each "pix" is associated with a focal dermal accumulation of immune cells, specifically lymphocytes and histiocytes. Consequently, these defects have been termed lymphohistiocytic proliferative cutaneous lesions (LPCLs). In farmed American alligators (Alligator mississippiensis), LPCLs have been associated with seropositivity against West Nile virus (WNV) and the presence of viral genome in the skin. Despite this association, the nature and pathogenesis of LPCLs remain unclear. Using immunohistochemistry and in situ hybridization, we unravel the microanatomy of LPCLs of alligators and localize WNV genome within the lesions. Our results show that LPCL lesions consist of de novo follicular aggregates of lymphocytes segregated into B- and T-cell zones, like tertiary lymphatic follicles of mammals and birds. Furthermore, the presence of WNV genome was highlighted by in situ hybridization in the macrophages of LPCLs, gut-associated lymphoid tissues, and the spleen. Our results suggest that LPCLs may form in American alligators' skin as part of a generalized lymphofollicular proliferation, likely as an immune response against WNV infection.

Classification schemes regarding canine subcutaneous mast cell tumors (csMCTs) remain elusive, lack consensus, and are prone to interobserver variability and bias. This observational study aimed to assess the reproducibility and the prognostic significance of volume-weighted mean nuclear volume ($\overline{v_v}$), a stereological estimation offering insights into nuclear size and its variability, in csMCTs. Thirty csMCTs were selected with information regarding outcome, and $\overline{v_v}$ was estimated using the "point-sampled intercept" method. Interobserver and intraobserver $\overline{v_v}$ reproducibility yielded concordance coefficients near or above 0.90. Regarding previously reported risk factors (pattern, mitotic count, and multinucleated cells), no statistically significant differences were identified between patterns and clinical outcome, nor between patterns and $\overline{v_v}$; however, the infiltrative pattern was represented more in the poorer outcome group and had higher $\overline{v_v}$ values. When comparing $\overline{v_v}$ and clinical outcome, a statistically significant difference emerged. Cases with poorer outcomes had higher $\overline{v_v}$ values ($\tilde{x}$ = 192.9) than cases with more favorable outcomes ($\tilde{x}$ = 120.5), and this association was statistically significant on both univariable and multivariable analyses. This study suggests that $\overline{v_v}$ is highly reproducible and is associated with clinical outcome in csMCTs.

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.

Intoxication of sheep and cattle by Astylus atromaculatus recently occurred in Uruguay and Argentina in association with severe drought. Although the disease was experimentally reproduced in sheep in the 1970s, there is limited information on clinical and pathologic findings of sheep experimentally intoxicated by this beetle. Here, we described the clinical, gross, and microscopic findings in 3 sheep orally dosed with A. atromaculatus (treatment group, TG) and in 2 control sheep (control group, CG) dosed with distilled water. Anorexia, lethargy, ruminal stasis, reluctance to move, prolonged recumbency, and bruxism were observed in the TG but not the CG sheep. Gross postmortem lesions were only observed in TG sheep and included fibrinonecrotizing enteritis affecting the duodenum, jejunum, and ileum, and multifocal hemorrhages in rumen, omasum, and abomasum. Microscopically, all 3 TG animals had multifocal necrosis in the small intestine; the lesions were most severe in the jejunum. Multifocal necrosis was seen in the mucosa of the rumen, omasum, and abomasum. No significant gross or microscopic abnormalities were observed in the 2 CG sheep. The study supports the role of A. atromaculatus in acute, fatal gastrointestinal disease like that previously described in experimental and spontaneous cases in sheep.

Acute pancreatitis (AP) is a life-threatening condition, with a higher mortality rate in men than women and in which estrogens might play a protective role. This study aimed to investigate sex-dependent differences in a mouse model of caerulein-induced AP. Thirty-six C57BL/6J mice (19 females and 17 males) were treated intraperitoneally with phosphate-buffered saline or caerulein, and sacrificed 12 hours, 2 days, or 7 days after the last injection. Blood was collected for amylase, lipase, and glucose determination. Severity and extent of inflammation, apoptosis, and acinar to ductal metaplasia (ADM) in pancreatic tissue were scored histologically and total macrophages, major histocompatibility complex (MHC)-II+ cells, M2 macrophages, T and B cells, neutrophils, apoptosis, and ADM were marked immunohistochemically and quantified by digital image analysis. Serum amylase had a peak at 12 hours, without differences between the sexes. In females, pancreatitis reached a peak at 12 hours with a fast recovery while, in males, the peak was delayed to day 2 with residual apoptosis still present. Macrophages were the main inflammatory cell population, followed by T cells, B cells and neutrophils, without differences between sexes. In males, CD206+ cells and apoptosis were higher at both days 2 and 7, and cytokeratin-19+ (CK19+) ADM was higher at day 7 compared with females. The results of this study revealed a faster onset and resolution of caerulein-induced AP in female mice compared with male mice, supporting a sex-dependent modulation of acute pancreatitis.

Coiled-coil domain containing 85c (Ccdc85c) is a causative gene for genetic hydrocephalus found in hemorrhagic hydrocephalus (hhy) mice. The Ccdc85c knockout (KO) rat has subcortical heterotopia with frequent brain hemorrhage as seen in hhy mice. In this study, we report aberrant alpha-smooth muscle actin (α-SMA) expression in the wall of lateral ventricle of the Ccdc85c KO rats. The α-SMA-positive cells were distributed at the dorsal, medial, and lateral regions of the lateral ventricle of KO rats. The expression of α-SMA was first observed on postnatal day 20 (P20) and became noticeably stronger at P26 when hydrocephalus was prominent. Double immunofluorescence showed co-expression of α-SMA with nestin, vimentin, and glial fibrillary acidic protein in the ventricular lining of KO rats. Therefore, we conclude that α-SMA-positive cells may represent an immature subpopulation of cells at adult age around the lateral ventricle of Ccdc85c KO rats.

The present study aimed to evaluate the histologic, histochemical, and immunohistochemical changes in buffalo livers with cystic echinococcosis. Noninfected and infected livers were collected from the freshly slaughtered buffalo at the Aligarh abattoir. Small pieces of both infected and noninfected livers (n = 5) were cut and processed for histologic and histochemical studies. Immunohistochemistry was performed using rabbit anti-CD3, CD19, and CD117 antibodies. The results revealed the presence of brood capsules and germinal and laminated membranes surrounded by a fibrous adventitial layer, followed by moderate and diffused infiltration of eosinophils, monocytes, neutrophils, lymphocytes, and marked focal infiltration of mast cells. The infected livers also had mild dilation of central veins and sinusoids, mild and focal necrosis of hepatic tissue, and congestion of central and portal veins. Periodic acid-Schiff reaction revealed marked glycogen depletion in the infected liver. Masson's trichrome stain showed marked deposition of collagen fibers in the portal area, adventitial layer, and between the hepatocytes compared with the noninfected liver, where deposition was found only in the portal area. The T-cell response was more pronounced than the B-cell response in infected liver. Thus, it can be concluded that hydatid cyst infection causes several pathological and biochemical changes and increased infiltration of inflammatory cells in the infected livers, suggesting the involvement of nonspecific immune responses against hydatid cysts. The T-cell response was more pronounced than B-cells, indicating the involvement of cell-mediated immunity against cystic echinococcosis. These findings may help to understand the local immune responses to cystic echinococcosis.