Differences in normal nasal computed tomography findings in different dog breeds.

Background: Computed tomography (CT) is the gold standard for diagnosing canine nasal diseases. However, it cannot easily detect minor abnormalities in inflammatory diseases because they are not accompanied by obvious morphological changes. Aim: The present study aimed to compare the differences in normal CT findings of turbinate structure and mucosa between breeds to establish criteria for CT diagnosis of inflammatory diseases of the nasal cavity. Methods: CT data from 77 dogs of 5 breeds without nasal diseases were retrospectively studied. The nasal air percentage, which reflects the volume of the nasal turbinate structure and mucosa, was measured. The nasal turbinate mucosa was measured for contrast enhancement reflecting blood flow. Measurements were performed in the ventral and ethmoid turbinate (ET) regions. Comparisons were made between breeds and sections. Results: The air percentage in the ventral and ET regions was significantly different between breeds. Contrast enhancement was significantly different between breeds only in the ET. Moreover, different breeds had different correlations between body weight, age, nose length, and air percentage. Conclusion: In this study, reference values for normal CT findings of the nasal structure and mucosa were obtained, taking into account the breed, measurement section, and patient factors. The results showed that the volume of the turbinate structure and contrast enhancement of nasal mucosa differed depending on the breed. The measured values also differed depending on the cross-sections and patient factors.

Use of amlodipine in the treatment of cats with systemic hypertension in Japan.

An increase in systemic blood pressure causes bleeding and ischemia owing to peripheral vascular breakdown, leading to various forms of organ damage. The brain, eyes, kidneys, and cardiovascular system are known target organs for hypertension. To our knowledge, no reports in Japan describe, in detail, the types of antihypertensive drugs used to treat hypertension in cats or its underlying causes. Therefore, we aimed to investigate the use of antihypertensive drugs in domestic cats with hypertension in Japan, the causes of hypertension, and the vital prognosis of these patients. In the present survey, we found that amlodipine was used alone (60/80 cats) or concomitantly (20/80 cats) in all cat patients with hypertension in Japan. We also determined that blood pressure measurements were not yet routinely performed on cats at veterinary clinics in Japan. Furthermore, we have new information suggesting that amlodipine administration in cats with hypertension, which lowers systolic arterial pressure levels to within the normal range (<140 mmHg), may have a negative impact on their survival. Routine blood pressure measurements for cats during their regular health checkups can help identify hypertension, and proper interpretation of blood pressure readings can facilitate suitable treatment measures.

Quantitative evaluation of middle ear radiopacity in French bulldogs using X-ray imaging.

Background: Radiographic examination of the middle ear in French bulldogs can be challenging due to their small ear cavity and thick walls. Quantifying opacity on radiographic images is required to determine normal or abnormal results. Aim: To quantify the radiographic opacity of the middle ear in French bulldogs and create a threshold for objective diagnosis. Methods: A study was conducted on 32 French Bulldogs using radiographic images. Significant difference tests were performed on the ears of patients with unilateral and bilateral middle ear filling on computed tomography. A threshold was established for detecting left-right asymmetry in the same individuals. In addition, comparisons were made between the filling and nonfilling middle ear groups to establish a threshold of pixel values that could determine single middle ear filling and nonfilling for different patient images. Results: Significant differences were observed in the left-right difference in max, left-right difference in max-ave, and left-right ratio of max-ave between unilateral and bilateral filling groups. The max-ave left-right ratio had the highest area under the curve value with a cutoff of 1.077% and 92.3% sensitivity. The item that showed a significant difference between middle ear groups with and without filling was corrected for nasopharyngeal pixel values with a cutoff of 1.028% and 85% sensitivity. Conclusion: Pixel value ratios in the middle ear region can detect asymmetries in ear densities. The max value in the region compared to the same image's nasopharyngeal region can determine the filling. Combining individual ear evaluations and symmetry improves accuracy.

Effects of Beraprost with or without NOS Inhibition on Plasma Aldosterone and Hemodynamics in Healthy Cats.

OBJECTIVES: The aim of the study was to evaluate the hemodynamic and RA system effects of the oral administration of the clinical dose of beraprost for feline CKD in healthy cats, and also to examine whether NOS inhibition reversed them. METHODS: A placebo-controlled pharmacological sequential design study was carried out to assess the plasma aldosterone and renin concentrations (PAC and PRC), blood pressure, heart rate, and exploratorily to estimate renal plasma flow (RPF) and renal vascular resistance (RVR) with simplified methods. RESULTS: Beraprost reduced PAC when compared to the placebo (p < 0.05); this was reversed when NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME) was added to the beraprost treatment (p < 0.01). No differences in the PRC or hemodynamic parameters were detected between beraprost and the placebo. The correlation ratios (η2) showed opposite relationships between beraprost and the added L-NAME effects on PAC, mean blood pressure (MBP), heart rate, estimated RPF (p < 0.001), estimated RVR (p < 0.01), and PRC (p < 0.05). CONCLUSIONS: In healthy cats, the clinical dose of beraprost suppresses PAC, which can be reversed by the inhibition of NOS.

Suspected renal interstitial cell tumor causing polycythemia in two dogs.

Here we report a case series of two dogs diagnosed as renal interstitial cell tumor (RICT) accompanied by elevated serum erythropoietin level and marked polycythemia. RICT is a rare tumor in dogs, originating from renal interstitial cells. While several renal tumors such as renal lymphoma, adenocarcinoma, carcinoma, sarcoma, fibrosarcoma and nephroblastoma may cause polycythemia, polycythemia caused by RICT has never been reported in dogs. The tumors in both dogs were solitary and lied within cortex or cortico-medullary junction. Histopathology revealed spindle-shaped cells suggesting mesenchymal origin, with no mitotic figures suggesting that the tumors in both dogs were benign. Following surgical removal of the affected kidney, serum erythropoietin level and polycythemia normalized in both dogs.

Comparative pharmacokinetics of tyrosine kinase inhibitor, lapatinib, in dogs and cats following single oral administration.

Lapatinib is an orally administered tyrosine kinase inhibitor used to treat human epidermal growth factor receptor 2 (HER2) -overexpressing breast cancers in humans. Recently, the potential of lapatinib treatment against canine urothelial carcinoma or feline mammary tumor was investigated. However, the pharmacokinetic studies of lapatinib in dogs and cats are not well-defined. In the present study, the pharmacokinetic characteristics of lapatinib in both cats and dogs after a single oral administration at a dose of 25 mg/kg were compared with each other. Lapatinib was administered orally to four female laboratory cats and four female beagle dogs. Blood samples were collected over time, and the plasma lapatinib concentrations were analyzed by HPLC. Following a single dose of 25 mg/kg, the averaged maximum plasma concentration (Cmax) of lapatinib in cats was 0.47 µg/mL and achieved at 7.1 hr post-administration, while the Cmax in dogs was 1.63 µg/mL and achieved at 9.5 hr post-administration. The mean elimination half-life was 6.5 hr in cats and 7.8 hr in dogs. The average area under the plasma concentration-time curve of dogs (37.2 hr·µg/mL) was significantly higher than that of cats (7.97 hr·µg/mL). These results exhibited slow absorptions of lapatinib in both animals after oral administration. The Cmax observed in cats was significantly lower and the half-life was shorter than those observed in dogs. Based on these results, a larger dose or shorter dosing intervals might be recommended in cats to achieve similar plasma concentration as dogs.

Multiple intra-abdominal fungal granulomas caused by Scedosporium apiospermum effectively treated with voriconazole in a Golden Retriever.

Scedosporium apiospermum is a saprophytic filamentous fungus that is pathogenic to dogs. This report describes a case of S. apiospermum infection that caused multiple large peritoneal fungal granulomas in a dog with a history of jejunojejunostomy. The lesions were firmly attached to multiple organs and could not be surgically removed. In such cases, no precedent for the response to the treatment of this disease exists, and all affected dogs have died. This is the first report of an effective medical treatment for multiple intra-abdominal fungal granulomas using voriconazole.

Derivation of a new model of lung adenocarcinoma using canine lung cancer organoids for translational research in pulmonary medicine.

Canine primary lung cancer (cPLC) is a rare malignant tumor in dogs, and exhibits poor prognosis. Effective therapeutic drugs against cPLC have not been established yet. Also, cPLC resembles human lung cancer in histopathological characteristics and gene expression profiles and thus could be an important research model for this disease. Three-dimensional organoid culture is known to recapitulate the tissue dynamics in vivo. We, therefore, tried to generate cPLC organoids (cPLCO) for analyzing the profiles of cPLC. After samples from cPLC and the corresponding normal lung tissue were collected, cPLCO were successfully generated, which recapitulated the tissue architecture of cPLC, expressed lung adenocarcinoma marker (TTF1), and exhibited tumorigenesis in vivo. The sensitivity of cPLCO to anti-cancer drugs was different among strains. RNA-sequencing analysis showed significantly upregulated 11 genes in cPLCO compared with canine normal lung organoids (cNLO). Moreover, cPLCO were enriched with the MEK-signaling pathway compared with cNLO. The MEK inhibitor, trametinib decreased the viability of several strains of cPLCO and inhibited the growth of cPLC xenografts. Collectively, our established cPLCO model might be a useful tool for identifying novel biomarkers for cPLC and a new research model for dog and human lung cancer.

Establishment of an experimental model of canine malignant mesothelioma organoid culture using a three-dimensional culture method.

Canine malignant mesothelioma (cMM) is a rare and drug-resistant malignant tumor. Due to few patients and experimental models, there have not been enough studies to demonstrate the pathogenesis of the disease and novel effective treatment for cMM. Since cMM resembles human MM (hMM) in histopathological characteristics, it is also considered a promising research model of hMM. Compared with conventional 2-dimensional (2D) culture methods, 3-dimensional (3D) organoid culture can recapitulate the properties of original tumor tissues. However, cMM organoids have never been developed. In the present study, we for the first time generated cMM organoids using the pleural effusion samples. Organoids from individual MM dogs were successfully generated. They exhibited the characteristics of MM and expressed mesothelial cell markers, such as WT-1 and mesothelin. The sensitivity to anti-cancer drugs was different in each strain of cMM organoids. RNA sequencing analysis showed cell adhesion molecule pathways were specifically upregulated in cMM organoids compared with their corresponding 2D cultured cells. Among these genes, the expression level of E-cadherin was drastically higher in the organoids than that in the 2D cells. In conclusion, our established cMM organoids might become a new experimental tool to provide new insights into canine and human MM therapy.

A case of a dog with paragonimiasis after consumption of raw deer meat.

A 6-year-old castrated male Cavalier King Charles Spaniel was referred to the Animal Medical Center, Tokyo University of Agriculture and Technology, for examination and treatment of recurrent pneumothorax. Chest radiography and computed tomography showed multiple cavitary lesions in the caudal right posterior lobe. These lesions were surgically excised via thoracotomy. Subsequent histopathological examination revealed paragonimiasis. In the postoperative review, we found that the owner had fed raw deer meat to the dog four months earlier. Deer meat has attracted attention as a source of Paragonimus in humans. To our knowledge, this is the first report of Paragonimus infection in a dog due to deer meat consumption.

Efficacy of cilostazol in canine bradyarrhythmia.

Recently, cilostazol, a phosphodiesterase III inhibitor, has been described as alternative medical treatment for canine bradyarrhythmia in cases for which pacemaker implantation was not indicated or available. In this retrospective study, we investigated the use and efficacy of cilostazol in dogs with bradyarrhythmia in Japan. Dogs that had been brought to the Tokyo University of Agriculture and Technology Animal Medical Center and 23 veterinary hospitals in Japan and been treated with cilostazol initially as the only therapeutic strategy for bradyarrhythmia between January 2010 and August 2021 were included in this study. Survival analyses were performed using Cox proportional hazards analysis, the log-rank test, and the generalized Wilcoxon test to evaluate the efficacy of cilostazol. Fifty-nine privately owned dogs were included in this study. In the survival time analysis, the risk of death was significantly lower and the survival rate was higher in cases in which cilostazol was administered at 10 mg/kg or more per dose. A third-degree atrioventricular block also significantly increased the risk of death and was associated with a lower survival rate. However, in some patients with a third-degree atrioventricular block, there was an increase in the ventricular rate and improvement in clinical symptoms without disappearance or decrease of the atrioventricular block. This study had several important findings that have not previously been reported concerning the use of cilostazol for canine bradyarrhythmia, including the appropriate dose in a clinical setting and the efficacy and prognosis according to the type of bradyarrhythmia.

Protective Effect on Pancreatic Acinar Cell by Maintaining Cardiac Output in Canine Heart Failure Model With Decreased Pancreatic Blood Flow.

Heart failure cause hypoperfusion-induced damage to abdominal organs due to decreased cardiac output (CO). Using a model dog with heart failure caused by rapid ventricular pacing (RVP), we have previously demonstrated that a decrease in CO reduces pancreatic blood flow (PBF). Furthermore, we have revealed that pancreatic acinar cell atrophy, which is a change in the pre-stage of pancreatitis was caused. However, the mechanism by which pancreatic acinar cell atrophy was caused in RVP dogs remains unknown. This study aimed to clarify the association between cardiac function, PBF, and histopathological changes in pancreatic acinar cells by administrating pimobendan, which increase CO, to RVP dogs. RVP dogs were divided into the control group (no medication, n = 5) and the pimobendan group (pimobendan at 0.25 mg/kg BID, n = 5). Non-invasive blood pressure measurement, echocardiography, and contrast-enhanced ultrasonography for PBF measurement were performed before initiating RVP and at 4 weeks after initiating RVP (4 weeks). At 4 weeks, the decreases in CO, mean blood pressure and PBF due to RVP were suppressed in pimobendan group. Furthermore, histopathological examination showed no changes in pancreatic acinar cells in the pimobendan group. Overall, it was clarified that the decrease in PBF due to cardiac dysfunction was a direct cause of pancreatic acinar cell atrophy. This suggests that maintaining PBF is clinically important for treating dogs with heart failure. In addition, these findings offer a reliable basis for developing new therapeutic strategies for heart failure in dogs, that is, pancreatic protection.

Establishment of an experimental model of normal dog bladder organoid using a three-dimensional culture method.

Dog bladder cancer (BC) is mostly muscle-invasive (MI) with poor prognosis, and its pathogenesis is close to human MIBC. Three-dimensional (3D) organoid culture ensures novel knowledge on cancer diseases including BC. Recently, we have established dog BC organoids (BCO) using their urine samples. BCO recapitulated the epithelial structures, characteristics, and drug sensitivity of BC-diseased dogs. However, organoids from dog normal bladder epithelium are not established yet. Therefore, the present study aimed to establish dog normal bladder organoids (NBO) for further understanding the pathogenesis of dog BC and human MIBC. The established NBO underwent various analyzes including cell marker expressions, histopathological structures, cancer-related gene expression patterns, and drug sensitivity. NBO could be produced non-invasively with a continuous culturing and recapitulated the structures and characteristics of the dog's normal bladder mucosal tissues. Different drug sensitivities were observed in each NBO. The analysis of RNA sequencing revealed that several novel genes were changed in NBO compared with BCO. NBO showed a higher expression of p53 and E-cadherin, but a lower expression of MDM2 and Twist1 compared with BCO. These results suggest that NBO could be a promising experimental 3D model for studying the developmental mechanisms of dog BC and human MIBC.

Evaluation of the Safety and Feasibility of Apheresis in Dogs: For Application in Metastatic Cancer Research.

In patients with solid tumors, circulating tumor cells (CTCs) spread in their blood and function as a seed for metastases. However, the study of CTCs has been limited by their rarity, low frequency, and heterogeneity. The efficient collection of CTCs will contribute to further research of metastatic cancers. Apheresis is a process in which the whole blood of an individual is passed through a machine that isolates a particular constituent and returns the remainder to the circulation. In the present study, we investigated the safety and feasibility of apheresis to separate peripheral blood monocytes (PBMCs), whose density is closely similar to that of CTCs, and to capture intravenously administered human breast cancer cells, MCF7s, from the dogs. No life-threatening events were observed in dogs during the apheresis process. The changes in the hemogram were transient and recovered gradually within a few days after apheresis. During apheresis, 50 mL of PBMCs could be collected from each dog. Notably, a thrombus was formed along the circuit wall during apheresis, which decreased the blood collection pressure. MCF7 cells were successfully captured by the apheresis machine. The captured cells were regrown in vitro and characterized compared with the original cells. In conclusion, apheresis could be safely performed in dogs to isolate CTCs with precautions to maintain hemodynamic stability.

Anti-tumor effect of trametinib in bladder cancer organoid and the underlying mechanism.

Bladder cancer (BC), a main neoplasm of urinary tract, is usually inoperable and unresponsive to chemotherapy. As a novel experimental model for muscle-invasive BC, we previously established a culture method of dog BC organoids. In the present study, the detailed in vitro and in vivo anti-tumor effects of trametinib were investigated by using this model. In each BC organoid strain, epidermal growth factor receptor (EGFR)/ERK signaling was upregulated compared with normal bladder cells. Trametinib even at a low concentration inhibited the cell viability of BC organoids and the activation of ERK through decreasing expression of c-Myc, ELK1, SIK1, and PLA2G4A. Trametinib arrested cell cycle of BC with few apoptosis. Dual treatment of BC organoids with trametinib and YAP inhibitor, verteporfin extremely inhibited the cell viability with apoptosis induction. Moreover, trametinib induced basal to luminal differentiation of BC organoids by upregulating luminal markers and downregulating basal ones. In vivo, trametinib decreased the tumor growth of BC organoids in mice and the xenograft-derived organoids from trametinib-administered mice showed enhanced sensitivity to carboplatin due to MSH2 upregulation. Our data suggested a new strategy of trametinib-YAP inhibitor or trametinib-carboplatin combination as a promising treatment of BC.

Histopathological changes in the pancreas due to decreased pancreatic blood flow in a canine tachycardia-induced cardiomyopathy model.

In dogs, pancreatic acinar cell injury is thought to be caused by decreased pancreatic blood flow due to heart failure. In previous our report, it demonstrated that decreased heart function causes a significant decrease in pancreatic blood flow in heart failure dog model caused by rapid ventricular pacing (RVP). However, the types of histopathological changes remain unclear. We aimed to verify the types of histopathological changes occurring in the pancreatic tissue due to decreased heart function. After RVP for 4 weeks, atrophy of pancreatic acinar cells, characterized by a decrease in zymogen granules, was observed in all areas of the pancreas. In conclusion, the result of this study suggests that attention should be paid to ischemia/hypoperfusion injury in the pancreas.

Analysis of blood clotting with the total thrombus analysis system in healthy dogs.

To date, coagulation tests are unable to reflect in vivo coagulation status in the same system, including platelet function, fibrin clot formation, and whole blood flow. The Total Thrombus Analysis System (T-TAS), which is a microfluidic assay that simulates conditions in vivo, measures whole blood flow at defined shear rates under conditions designed to assess platelet function (PL-chip) or coagulation and fibrin clot formation (AR-chip). The T-TAS records occlusion start time, occlusion time, and area under the curve. We evaluated this test in healthy control dogs. We also investigated the effect in vivo of acetylsalicylic acid (ASA), and the effect in vitro of an anticoagulation drug (dalteparin; low-molecular-weight heparin; LMWH). The CV of the AUC of both chips was good (CVs of 6.45% [PL] and 1.57% [AR]). The inhibition of platelet function by ASA was evident in the right-shift in the PL test pressure curve. The right-shift in the AR test pressure curves showed that the administration of LMWH inhibited both platelets and the coagulation cascade. The T-TAS may be useful in the evaluation of canine blood coagulation.

Evaluation of cerebral blood flow in the hippocampus, thalamus, and basal ganglia and the volume of the hippocampus in dogs before and during treatment with prednisolone.

OBJECTIVE: To examine whether glucocorticoid (GC) administration alters hippocampal cerebral blood flow (CBF) or volume in dogs. ANIMALS: 6 clinically normal adult Beagles. PROCEDURES: Each dog underwent CT and MRI to measure the CBF in the hippocampus, basal ganglia, thalamus, and cerebral cortex and the volume of the hippocampus in each hemisphere of the brain before (day 0) and during (days 7 and 21) a 21-day treatment with prednisolone (1.0 mg/kg, PO, q 24 h) and famotidine (0.5 mg/kg, PO, q 12 h). Results for hippocampal volume, anesthesia-related variables, and semiquantitative measurements of CBF (hemisphere-specific ratios of the CBF in the hippocampus, basal ganglia, and thalamus relative to the CBF in the ipsilateral cerebral cortex and the left cerebral cortex CBF-to-right cerebral cortex CBF ratio) were compared across assessment time points (days 0, 7, and 21). RESULTS: The ratios of CBF in the right hippocampus and right thalamus to that in the right cerebral cortex on day 21 were significantly lower than those on day 0. No meaningful differences were detected in results for the hippocampal volume in either hemisphere or for the anesthesia-related variables across the 3 time points. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that GC administration reduced CBF in the hippocampus and thalamus in dogs of the present study, similar to that which occurs in humans. Research on GC-related brain alteration in dogs could potentially contribute to advancements in understanding Alzheimer disease in humans and neurodegenerative conditions in dogs.

Establishment of 2.5D organoid culture model using 3D bladder cancer organoid culture.

Three-dimensional (3D) organoid culture holds great promises in cancer precision medicine. However, Matrigel and stem cell-stimulating supplements are necessary for culturing 3D organoid cells. It costs a lot of money and consumes more time and effort compared with 2D cultured cells. Therefore, the establishment of cheaper and Matrigel-free organoid culture that can maintain the characteristics of a part of 3D organoids is demanded. In the previous study, we established a dog bladder cancer (BC) 3D organoid culture system by using their urine samples. Here, we successfully isolated cells named "2.5D organoid" from multiple strains of dog BC 3D organoids using 2.5 organoid media. The cell proliferation speed of 2.5D organoids was faster than parental 3D organoid cells. The expression pattern of stem cell markers was close to 3D organoids. Injection of 2.5D organoid cells into immunodeficient mice formed tumors and showed the histopathological characteristics of urothelial carcinoma similar to the injection of dog BC 3D organoids. The 2.5D organoids had a similar sensitivity profile for anti-cancer drug treatment to their parental 3D organoids. These data suggest that our established 2.5D organoid culture method might become a reasonable and useful tool instead of 3D organoids in dog BC research and therapy.

Comparison of pancreatic and renal blood flow in a canine tachycardia-induced cardiomyopathy model.

The pancreas is believed to be vulnerable to hypoperfusion. In dogs with acute pancreatitis, pancreatic ischemia due to heart failure can worsen the condition. However, changes in pancreatic blood flow associated with decreased cardiac function have not been previously studied in dogs. Therefore, we aimed to identify and compare changes in pancreatic versus renal blood flow as a result of cardiac dysfunction. Seven dogs were subjected to rapid ventricular pacing to create heart failure models. Noninvasive blood pressure measurement, ultrasonic cardiography, contrast-enhanced ultrasonography for pancreatic blood flow measurement, and para-aminohippuric acid clearance for renal blood flow measurement were performed before starting and at 2 and 4 weeks after starting the pacing. Left ventricular cardiac output and mean blood pressure decreased at 2 and 4 weeks after starting the pacing, and pancreatic blood flow decreased at 2 and 4 weeks after starting the pacing. However, renal blood flow did not change at 2 weeks but decreased 4 weeks after starting the pacing. Overall, this study demonstrated that reduced pancreatic blood flow due to cardiac dysfunction occurs, similar to renal blood flow. This suggests that decreased pancreatic blood flow is not unusual and may frequently occur in dogs with heart failure. The results of this study support the speculation that heart failure can exacerbate acute pancreatitis. Additionally, this study provides useful basic information for designing further studies to study this association.