Neutrophils are important effector cells of the innate immune system, traditionally regarded to have a short life span. The goal of this study was to evaluate the effect of the whole blood storage on neutrophil functions, e.g., viability, antimicrobial effect, neutrophil extracellular trap (NET) formation and phagocytosis. Therefore, fresh porcine whole blood was compared to whole blood stored for 24 h in the dark at room temperature. Different cell parameters in whole blood and in isolated neutrophils were analyzed. The following parameters were analyzed: cell count, band and segmented neutrophil count, viability, cholesterol content, release of free DNA as a marker for cell death, phagocytic activity in whole blood and in isolated neutrophils, the transmigration rate of neutrophils to IL8 stimulus, the production of reactive oxygen species (ROS), and the formation of NETs. It was observed that the number of isolated neutrophils decreased over time, indicating cell death occurs during 24 h of blood storage. However, the surviving neutrophils isolated from stored blood reacted comparably or even showed enhanced antimicrobial activity in the case of phagocytosis of Streptococcus (S.) suis, ROS production, and transmigration. The slightly altered cholesterol level of the harvested neutrophils in stored blood when compared to fresh blood partially explains some of the detected differences.

BackgroundContinuous glucose monitoring systems have been validated for eu‐ and hyperglycemic cats. The FreeStyle Libre 2 (FSL2) is sufficiently accurate in people during hypoglycemia to guide critical treatment decisions without confirmation of blood glucose concentration (BG).ObjectivesAssess FSL2 accuracy in cats with hypoglycemia.AnimalsNine healthy, purpose‐bred cats.MethodsHyperinsulinemic‐hypoglycemic clamps were performed by IV infusion of regular insulin (constant rate) and glucose (variable rate). Interstitial glucose concentration (IG), measured by FSL2, was compared to BG measured by AlphaTrak2. Data were analyzed for all paired measurements (n = 364) and separately during stable BG (≤1 mg/dL/min change over 10 minutes). Pearson's r test, Bland‐Altman test, and Parkes Error Grid analysis respectively were used to determine correlation, bias, and clinical accuracy (P < .05 considered significant).ResultsOverall, BG and IG correlated strongly (r = 0.83, P < .0001) in stable glycemia and moderately at all rates of change (r = 0.69, P < .0001). Interstitial glucose concentration underestimated BG in euglycemia, but the BG‐IG difference was progressively smaller as BG decreased (12.9 ± 12.2, 8.8 ± 11.2, −3.2 ± 7.4, and −7.8 ± 5.2 mg/dL in the ranges of 80‐120 [n = 64], 60‐79 [n = 29], 50‐59 [n = 71], and 29‐49 mg/dL [n = 53], respectively).ConclusionsAlthough IG underestimates BG throughout most of the hypo‐euglycemic range, IG generally overestimates BG in marked hypoglycemia (<60 mg/dL). It is therefore imperative to evaluate FSL2 results in this critical range with caution.