Objective To determine if platelet additive solutions (PAS) decrease the occurrence and degree of platelet storage lesions, maintain platelet function, and extend storage time in vitro beyond 5 days at 22°C when compared to platelets stored in plasma only. Design Prospective, ex vivo experimental controlled study. Setting Research laboratory in a school of veterinary medicine. Animals Twelve units of canine platelet concentrate prepared from fresh whole blood donations. Interventions Platelet concentrates were aliquoted into 4 units and stored at room temperature (22°C) under constant agitation in either 100% plasma (control) or 35% plasma and 65% of 1 of 3 different PAS (Plasma‐Lyte A, Isoplate, and InterSol) for 7 days. At days 0, 3, 5, and 7, samples were analyzed for presence of swirling, degree of aggregate formation, platelet count, platelet indices, glucose, lactate, lactate dehydrogenase, Pvo2, and Pvco2 concentrations, aggregation via light aggregometry, and activation percentage based on flow cytometric measurement of surface P‐selectin. Bacterial cultures were performed on days 0, 5, and 7. Measurements and main results Isoplate had a higher incidence of aggregate formation on day 0 (n = 2), and Plasma‐Lyte A had a higher incidence of loss of swirl on day 7 (n = 5). Plasma‐stored samples had significantly higher platelet counts (P < 0.001), pH (P < 0.05), Pvco2 (P < 0.001), and lactate (P < 0.001), and significantly lower lactate dehydrogenase (P < 0.05) as compared to all PAS. The mean pH remained above 7.2 in PAS and plasma. There was no difference in platelet activation between plasma and PAS. Changes in platelet indices, glucose consumption, and maximum aggregation varied by storage solution. There was no bacterial growth seen in any samples. Conclusions The 3 PAS performed similarly and could all be considered as potential replacements for plasma during the room temperature storage of canine platelet concentrate for up to 7 days.

Poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) have been considerably studied as a promising biodegradable delivery system to induce effective immune responses and to improve stability, safety, and cost effectiveness of vaccines. The study aimed at evaluating early inflammatory effects and cellular safety of PLGA NPs, co-encapsulating ovalbumin (PLGA/OVA NPs), as a model antigen and the adjuvant monophosphoryl lipid A (PLGA/MPLA NPs) as an adjuvant, on primary canine macrophages. The PLGA NPs constructs were prepared following the emulsion-solvent evaporation technique and further physic-chemically characterized. Peripheral blood mononuclear cells were isolated from canine whole blood by magnetic sorting and further cultured to generate macrophages. The uptake of PLGA NP constructs by macrophages was demonstrated by flow cytometry, transmission electron microscopy and confocal microscopy. Macrophage viability and morphology were evaluated by trypan blue exclusion and light microscopy. Macrophages were immunophenotyped for the expression of MHC-I and MHC-II and gene expression of Interleukin-10 (IL-10), Interleukin-12 (IL-12p40), and tumor necrosis factor alpha (TNF-α) were measured. The results showed that incubation of PLGA NP constructs with macrophages revealed effective early uptake of the PLGA NPs without altering the viability of macrophages. PLGA/OVA/MPLA NPs strongly induced TNF-α and IL-12p40 expression by macrophages as well as increase relative expression of MHC-I but not MHC-II molecules. Taken together, these results indicated that PLGA NPs with addition of MPLA represent a good model, when used as antigen carrier, for further, in vivo, work aiming to evaluate their potential to induce strong, specific, immune responses in dogs.

BackgroundMycophenolate mofetil (MMF), the prodrug of mycophenolic acid (MPA), is becoming increasingly popular as an alternative immunosuppressant in feline medicine. Pharmacokinetic information is not available for cats.ObjectiveThe purpose of this study was to determine whether MMF is biotransformed into the active metabolite MPA and to evaluate the disposition of MPA after a 2‐hour constant rate intravenous (IV) infusion of MMF in healthy cats.AnimalsHealthy cats (n = 6).MethodsThis was a prospective pilot study. All cats were administered MMF at 20 mg/kg every 12 hours over a 2‐hour constant rate infusion for 1 day. The concentrations of MPA and its derivatives in blood were determined using a validated UHPLC–UV method.ResultsAll cats biotransformed MMF into MPA. The mean AUC0‐14 h ranged from 6 to 50 h*mg/L after IV dosing of MMF. Transient large bowel diarrhea was recorded in 2 of 6 cats after medication administration.Conclusion and Clinical ImportanceThe disposition of MPA in plasma was highly variable, which could result in high interindividual variability in the safety and efficacy of treatment with MMF in cats.

OBJECTIVE To evaluate the plasma disposition of mycophenolic acid (MPA) and its derivatives MPA glucuronide and MPA glucoside after twice-daily infusions of mycophenolate mofetil (MMF) in healthy cats for 3 days and to assess the effect of MMF administration on peripheral blood mononuclear cell (PBMC) counts and CD4+-to-CD8+ ratios. ANIMALS 5 healthy adult cats. PROCEDURES MMF was administered to each cat (10 mg/kg, IV, q 12 h for 3 days). Each dose of MMF was diluted with 5% dextrose in water and then administered over a 2-hour period with a syringe pump. Blood samples were collected for analysis. A chromatographic method was used to quantitate concentrations of MPA and its metabolites. Effects of MMF on PBMC counts and CD4+-to-CD8+ ratios were assessed by use of flow cytometry. RESULTS All cats biotransformed MMF into MPA. The MPA area under the plasma concentration–time curve from 0 to 14 hours ranged from 14.6 to 37.6 mg·h/L and from 14.4 to 22.3 mg·h/L after the first and last infusion, respectively. Total number of PBMCs was reduced in 4 of 5 cats (mean ± SD reduction, 25.9 ± 15.8% and 26.7 ± 19.3%) at 24 and 48 hours after the end of the first infusion of MMF, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Plasma disposition of MPA after twice-daily IV infusions for 3 days was variable in all cats. There were no remarkable changes in PBMC counts and CD4+-to-CD8+ ratios.

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