Platelet activation has a major role in hemostasis and thrombosis. Various agonists including adenosine diphosphate (ADP) and thrombin interact with G protein-coupled receptors (GPCRs) which transduce signals through various G proteins. Recent studies have elucidated the role of GPCRs and their corresponding G proteins in the regulation of events involved in platelet activation. However, agonist-induced platelet activation in companion animals has not been elucidated. This study was designed to characterize the platelet response to various agonists in dog platelets. We found that 2-methylthio-ADP-induced dog platelet aggregation was blocked in the presence of either P2Y₁ receptor antagonist MRS2179 or P2Y₁₂ receptor antagonist AR-C69931MX, suggesting that co-activation of both the P2Y₁ and P2Y₁₂ receptors is required for ADP-induced platelet aggregation. Thrombin-induced dog platelet aggregation was inhibited in the presence of either AR-C69931MX or the PKC inhibitor GF109203X, suggesting that thrombin requires secreted ADP to induce platelet aggregation in dog platelets. In addition, thrombin-mediated Akt phosphorylation was inhibited in the presence of GF109203X or AR-C69931MX, indicating that thrombin causes Gi stimulation through the P2Y₁₂ receptor by secreted ADP in dog platelets. Unlike human and murine platelets, protease-activated receptor 4 (PAR4)-activating peptide AYPGKF failed to cause dog platelet aggregation. Moreover, PAR1-activating peptide SFLLRN or co-stimulation of SFLLRN and AYPGKF failed to induce dog platelet aggregation. We conclude that ADP induces platelet aggregation through the P2Y₁ and P2Y₁₂ receptors in dogs. Unlike human and murine platelets, selective activation of the PAR4 receptor may be insufficient to cause platelet aggregation in dog platelets.
Adenosine Diphosphate ; Animals ; Blood Platelets ; Dogs ; GTP-Binding Proteins ; Hemostasis ; Humans ; Pets ; Phosphorylation ; Platelet Activation ; Platelet Aggregation ; Receptors, Proteinase-Activated ; Thrombin ; Thrombosis

BACKGROUND: Unfractionated heparin is commonly used for anticoagulation in extracorporeal membrane oxygenation (ECMO). Several studies have shown that nafamostat mesilate (NM) has comparable clinical outcomes to unfractionated heparin. This study compared anticoagulation with NM and heparin in a large-animal model. METHODS: Beagle dogs (n=8; weight, 6.5–9 kg) were placed on venovenous ECMO. Blood samples were taken every hour and the following parameters were compared: hemoglobin level, activated partial thromboplastin time (aPTT), thromboelastography (TEG) data, platelet function, and inflammatory cytokine levels. RESULTS: In both groups, the aPTT was longer than the baseline value. Although the aPTT in the NM group was shorter than in the heparin group, the TEG parameters were similar between the 2 groups. Hemoglobin levels decreased in both groups, but the decrease was less with NM than with heparin (p=0.049). Interleukin (IL)-1β levels significantly decreased in the NM group (p=0.01), but there was no difference in the levels of tumor necrosis factor alpha or IL-10 between the 2 groups. CONCLUSION: NM showed a similar anticoagulant effect to that of unfractionated heparin, with fewer bleeding complications. NM also had anti-inflammatory properties during ECMO. Based on this preclinical study, NM may be a good alternative candidate for anticoagulation in ECMO.
Animals ; Anticoagulants ; Blood Platelets ; Dogs ; Extracorporeal Membrane Oxygenation* ; Hemorrhage ; Heparin ; Interleukin-10 ; Interleukins ; Mesylates* ; Partial Thromboplastin Time ; Thrombelastography ; Tumor Necrosis Factor-alpha

Blood group determination in dogs is an important factor in transfusion medicine to minimize immediate or delayed adverse reactions after red blood cells transfusion in small animal clinics. Dog erythrocyte antigen (DEA) 1 is the most important blood type due to its high degree of antigenicity causing acute transfusion adverse reactions. The aim of this study was to investigate the prevalence of DEA 1 in various dog breeds in Korea. As a result of testing 592 blood samples from more than 35 dog breeds, DEA 1 blood typing for each breed showed that 57.8% of Malteses, 63.3% of Poodles, 76.2% of Mastiff-like dogs, 72.5% of Pomeranians, 47.7% of Shih Tzus, 70.3% of mixed breeds, 60.0% of Yorkshire Terriers, and 71.4% of Beagles were DEA 1-positive. Miniature Schnauzers and Jindo breeds had a significantly high prevalence (100%) of DEA 1-positive dogs compared to that in other small breed dogs. This is the first report of immunochromatography-detected DEA 1 prevalence in various domestic dog breeds. Although additional studies need clarifying the potential blood transfusion risks in domestic breed dogs with DEA 1, the results of this study may be useful when selecting a blood donor.
Animals ; Blood Donors ; Blood Group Antigens ; Blood Grouping and Crossmatching ; Blood Transfusion ; Dogs ; Erythrocytes ; Humans ; Immunochromatography ; Korea ; Prevalence ; Transfusion Medicine ; Transfusion Reaction

Adipose tissue-derived stem cell (ASCs) are an attractive source of stem cells with therapeutic applicability in various fields for regenerating damaged tissues because of their stemness characteristics. However, little has reported on evaluating adverse responses caused by human ASC therapy. Therefore, in the present study, a clinical assessment after human ASC transplantation into dogs was undertaken. A total of 12 healthy male dogs were selected and divided into four groups: saline infusion, saline bolus, ASC infusion, and ASC bolus groups. Physical assessment and blood analysis were performed following ASC transplantation, and the concentrations of angiogenic factors, and pro- and anti-inflammatory cytokines were measured by enzyme-linked immunosorbent assay (ELISA). There were no adverse vital sign responses among the dogs. Blood analyses revealed no remarkable complete blood count or serum chemistry results. ELISA results for angiogenic and anti-inflammatory factors including matrix metalloproteinase 9 (MMP9), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), and interleukin-10 (IL-10) were significantly higher in the two ASCs groups than in the controls. In conclusion, this study demonstrated that transplantation of human ASCs produced no adverse effects and could be used safely in dogs. In addition, human ASCs could be involved in modulating secretions of angiogenic factors including MMP9, VEGF, bFGF, and HGF and anti-inflammatory factor IL-10.
Angiogenesis Inducing Agents ; Animals ; Blood Cell Count ; Chemistry ; Cytokines ; Dogs ; Enzyme-Linked Immunosorbent Assay ; Fibroblast Growth Factor 2 ; Hepatocyte Growth Factor ; Humans ; Interleukin-10 ; Male ; Matrix Metalloproteinase 9 ; Stem Cell Transplantation ; Stem Cells ; Transplantation ; Vascular Endothelial Growth Factor A ; Vital Signs

This study compared effects of isoflurane inhalation (ISO) and propofol-remifentanil combined total intravenous anesthesia (TIVA) on oxygenation during thoracoscopic lung lobectomy with 30-min one-lung ventilation (1LV). Thoracoscopic right middle lung lobectomy was performed in ten dogs divided into ISO and TIVA groups, and cardiopulmonary parameters were measured with blood gas analysis. Throughout the study, isoflurane was inhaled up to 1.5%, and the infusion rates of propofol and remifentanil were 0.2 to 0.4 mg/kg/min and 6 to 11 µg/kg/h, respectively. Cardiac index was not affected in the ISO group, but it increased during 1LV in the TIVA group. There were significant alterations in arterial oxygen pressure, arterial oxygen saturation, oxygen content, and shunt fraction associated with 1LV in each group. However, oxygen delivery did not decrease significantly due to open chest condition, 1LV, or surgical maneuver in either group, rather it increased during 1LV in the TIVA group. All parameters showed no significant difference between groups. Pulmonary vascular resistant index was unaffected in both groups, and there was no difference between groups except in re-ventilation phase. Accordingly, the effect of both anesthetic regimens on oxygenation was not different between groups and can be used with short-term 1LV for thoracoscopic lung lobectomy in dogs.
Anesthesia ; Anesthesia, Intravenous ; Animals ; Arterial Pressure ; Blood Gas Analysis ; Dogs ; Inhalation ; Isoflurane ; Lung ; One-Lung Ventilation ; Oxygen ; Propofol ; Thorax

Acute lymphocytic leukemia (ALL) is uncommon lymphoid malignancy in dogs, and its diagnosis is challenging. A 14-year-old spayed female mixed breed dog was transferred to a veterinary medical teaching hospital for an immediate blood transfusion. The dog showed lethargy, pale mucous membranes, and a weak femoral pulse. Complete blood count revealed non-regenerative anemia and severe leukopenia with thrombocytopenia. ALL was tentatively diagnosed based on the predominance of immature lymphoblasts on blood film examination. For confirmation of lymphoid malignancy, PCR for antigen receptor rearrangement (PARR) on a peripheral blood sample and flow cytometry analysis were performed after blood transfusion. Flow cytometry analysis revealed that lymphocyte subsets were of normal composition, but PARR detected a T-cell malignancy. The dog was diagnosed with ALL and survived 1 wk after diagnosis. In conclusion, after blood transfusion, flow cytometry was not a reliable diagnostic method for an ALL dog, whereas PARR could detect lymphoid malignancy. Our results suggest that PARR should be the first-line diagnostic tool to detect canine lymphoid malignancy after a blood transfusion.
Adolescent ; Anemia ; Animals ; Blood Cell Count ; Blood Transfusion* ; Diagnosis* ; Dogs* ; Female ; Flow Cytometry ; Hospitals, Teaching ; Humans ; Lethargy ; Leukopenia ; Lymphocyte Subsets ; Methods ; Mucous Membrane ; Polymerase Chain Reaction* ; Precursor Cell Lymphoblastic Leukemia-Lymphoma* ; Receptors, Antigen* ; T-Lymphocytes ; Thrombocytopenia

The aim of this study was to compare serum nitrotyrosine concentrations in healthy dogs with those in dogs with myxomatous mitral valve disease (MMVD). Fifty client-owned dogs were included in this study. Based on echocardiographic results, dogs were categorized into healthy (control), mild-, moderate-, and severe-MMVD groups. Serum nitrotyrosine concentrations were determined from enzyme-linked immunosorbent assays. No significant difference between control dogs and dogs with mild MMVD was detected (p = 0.31). However, dogs with moderate MMVD had significantly higher serum concentrations of nitrotyrosine (p = 0.04) than that in controls, and dogs with severe MMVD had significantly lower serum concentrations of nitrotyrosine (p = 0.03) than that in moderate MMVD dogs. There were negative correlations in the association of serum nitrotyrosine with age (n = 30, R²= 0.067, p = 0.27), left atrial-to-aortic root diameter ratio (n = 30, R²= 0.02, p = 0.57), and platelet count (n = 30, R²= 0.39, p = 0.003); however, only the platelet correlation was significant. Among dogs with MMVD, there was no significant difference in serum nitrotyrosine concentration between males and females. The results of this study suggest that tyrosine nitration end-products might be potential biomarkers for the detection of MMVD in dogs.
Animals ; Biomarkers ; Blood Platelets ; Dog Diseases ; Dogs* ; Echocardiography ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Male ; Mitral Valve* ; Peroxynitrous Acid ; Platelet Count ; Tyrosine

BACKGROUNDShensong Yangxin (SSYX), a traditional Chinese herbal medicine, has long been used clinically to treat arrhythmias in China. However, the mechanism of SSYX on atrial fibrillation (AF) is unknown. In this study, we tested the hypothesis that the effect of SSYX on the progression of paroxysmal AF is correlated with the regulation of autonomic nerve activity.

METHODSEighteen mongrel dogs were randomly divided into control group (n = 6), pacing group (n = 6), and pacing + SSYX group (n = 6). The control group was implanted with pacemakers without pacing; the pacing group was implanted with pacemakers with long-term intermittent atrial pacing; the pacing + SSYX group underwent long-term intermittent atrial pacing and SSYX oral administration.

RESULTSCompared to the pacing group, the parameters of heart rate variability were lower after 8 weeks in the pacing + SSYX group (low-frequency [LF] component: 20.85 ± 3.14 vs. 15.3 ± 1.89 ms 2 , P = 0.004; LF component/high-frequency component: 1.34 ± 0.33 vs. 0.77 ± 0.15, P < 0.001). The atrial effective refractory period (AERP) was shorter and the dispersion of the AERP was higher after 8 weeks in the pacing group, while the changes were suppressed by SSYX intake. The dogs in the pacing group had more episodes and longer durations of AF than that in the pacing + SSYX group. SSYX markedly inhibited the increase in sympathetic nerves and upregulation of tumor necrosis factor-alpha and interleukin-6 expression in the pacing + SSYX group. Furthermore, SSYX suppressed the decrease of acetylcholine and α7 nicotinic acetylcholine receptor protein induced by long-term intermittent atrial pacing.

CONCLUSIONSSSYX substantially prevents atrial electrical remodeling and the progression of AF. These effects of SSYX may have association with regulating the imbalance of autonomic nerve activity and the cholinergic anti-inflammatory pathway.

Acetylcholine ; blood ; Animals ; Atrial Fibrillation ; drug therapy ; metabolism ; Autonomic Pathways ; drug effects ; Blotting, Western ; Dogs ; Drugs, Chinese Herbal ; therapeutic use ; Electrophysiology ; Enzyme-Linked Immunosorbent Assay ; Heart Rate ; drug effects ; Immunohistochemistry ; Interleukin-6 ; blood ; Models, Animal ; Tumor Necrosis Factor-alpha ; blood ; alpha7 Nicotinic Acetylcholine Receptor ; blood

Small-breed dogs (n = 168; weight < 15 kg) diagnosed with myxomatous mitral valve degeneration based on a routine clinical examination, radiology, electrocardiography, and echocardiography at the Seoul National University Veterinary Medical Teaching Hospital were included in this study. Survival periods were determined, and there were significant differences in survival rates among the three International Small Animal Cardiac Health Council classes. The mean follow-up period was 14.3 ± 12.1 months. Univariate analysis revealed that dyspnea, pulmonary edema, and vertebral heart score were significantly associated with survival time (p < 0.05). Additionally, age, left atrial-to-aortic root ratio, ejection fraction, and left ventricular end diastolic volume were associated with an increased risk of death (p < 0.1), while body weight, body condition score, systolic blood pressure, arrhythmia, syncope, fractional shortening, and end systolic volume were not associated with an increased risk of death. These results suggest that among the assessed variables dyspnea, pulmonary edema, and vertebral heart score could be useful prognostic factors for providing patient information to owners.
Animals ; Arrhythmias, Cardiac ; Blood Pressure ; Body Weight ; Dogs* ; Dyspnea ; Echocardiography ; Electrocardiography ; Follow-Up Studies ; Heart ; Heart Failure ; Hospitals, Teaching ; Humans ; Mitral Valve* ; Prognosis ; Pulmonary Edema ; Retrospective Studies* ; Seoul ; Stroke Volume ; Survival Rate ; Syncope

Two young dogs were referred to the Veterinary Medical Teaching Hospital of Konkuk University, one for examination of vaginal discharge and the other after being hit by a car. Dog 1 exhibited a high neutrophil count on Gram-stained vaginal smears, marked leukocytosis on a complete blood count, and uterine enlargement on ultrasonography. In dog 2, a markedly enlarged right uterine horn containing echogenic debris was found incidentally on ultrasonography. A tentative diagnosis of pyometra was made in both cases and ovariohysterectomy was performed. Purulent material was collected from each uterine horn and submitted separately for aerobic and anaerobic bacterial culture; all culture results were negative. The white blood cell count revealed normal limits 2 days post operation in dog 1 and 4 days post operation in dog 2. Positive bacterial cultures are usually obtained from dogs with pyometra, and antibiotic selection is based on the results of culture and sensitivity testing in the event of failure of empiric antibiotic therapy. However, in the cases reported here, no bacterial growth was identified from the uterine samples despite the presence of purulent material. A short course of empiric antibiotic therapy was administered. This is the first known report describing sterile pyometra in dogs.
Animals ; Blood Cell Count ; Diagnosis ; Dogs* ; Horns ; Hospitals, Teaching ; Leukocyte Count ; Leukocytosis ; Neutrophils ; Pyometra* ; Ultrasonography ; Vaginal Discharge ; Vaginal Smears