RESUMO
OBJECTIVE: To evaluate the effects of darbepoetin on platelet population and reactivity in healthy cats (HCs) and azotemic cats with remnant kidney (RK) model-induced chronic kidney disease. ANIMALS: 12 purpose-bred domestic shorthair cats (n = 6 HCs and n = 6 RK). METHODS: In this pilot study, all cats received darbepoetin (1 µg/kg, SC) on days 0, 7, and 14. Blood was sampled at baseline and on days 3, 10, 15, 17, 20, and 21. At each time point, a CBC was performed, platelet aggregometry was assessed by impedance and optical methods, and platelet P-selectin (CD62P) was quantified before and after thrombin stimulation. Additionally, reticulated platelets were quantified using both thiazole orange staining and proprietary analysis by the CBC analyzer. For RK cats, systemic blood pressure (BP) was serially measured. RESULTS: No adverse effects of darbepoetin were seen. There was no statistically significant change in platelet count between or within groups at any time point. Hematocrit increased significantly over time in the RK but not the HC group. RBC reticulocyte numbers in both groups increased over time. Reticulated platelet percentage did not increase in either group. Differences in platelet reactivity within or between groups were not seen in the aggregometry or flow cytometric assessments. In RK cats, indirect BP did not significantly change during the study. CLINICAL RELEVANCE: This preliminary investigation did not find evidence that darbepoetin administration impacted platelet number, reactivity, nor reticulated platelet count. Anemic RK cats experienced increased hematocrit and RBC reticulocytes as expected with darbepoetin therapy.
RESUMO
Introduction: In veterinary medicine there are few readily available products for platelet transfusion to patients with thrombocytopenia. Commercial tabletop platelet concentrating systems have recently become available to veterinarians, primarily directed towards uses associated with regenerative medicine. These systems could potentially be used to produce fresh concentrated platelets for use in transfusion medicine. This study evaluated the concentration, activation, and sterility of a double centrifugation platelet concentrate (PC) produced by a commercial benchtop system. Methods: Ten healthy dogs were studied. Whole blood was collected and mixed with ACD-A in a 1:7.6 ratio of ACD-A to whole blood. 12 mL of this mixture was processed into PC via single centrifugation, while 60 mL of the anticoagulated whole blood was processed via a commercial double centrifugation system. Both types of PC were evaluated for platelet concentration, CD62P expression with and without thrombin stimulation, and for sterility. Results: Mean platelet count in the double centrifuged PC was 863 ± 352 × 103/µL, with very low white blood cell contamination (median of 0.47 × 103 leukocyte/µL (range 0.15-2.18 × 103/µL)). The double-centrifuged PC had similar baseline activation characteristics (as determined by P-selectin expression) as the single centrifuge PC (0.76% vs. 0.72% unstimulated, 30.5% vs. 34.9% stimulated, p = 0.432). Discussion: The benchtop PC system studied here did not cause activation of platelets during production and produced a sterile product that can be further investigated as a source of fresh platelet concentrates for transfusion purposes.
