Abstract
BACKGROUND: Red blood cells (RBC) are uniquely susceptible to oxidative injury. Oxidative stress is both a cause for, and effect, of anemia in people but this has been minimally documented in dogs. OBJECTIVE: To describe direct and indirect markers of oxidative stress in anemic dogs. HYPOTHESIS: Anemic dogs will have oxidative stress when compared to healthy dogs. ANIMALS: Forty-seven dogs with anemia (10 with hemolytic anemia) and 70 healthy control dogs. METHODS: Prospective, cross-sectional study. Anemic dogs were identified from the patient population, and medical records were reviewed to classify the anemia as hemolytic or nonhemolytic. Flow cytometry was used to detect reactive oxygen species (ROS) in erythrocyte isolates. Reduced glutathione (GSH) concentrations were measured in both plasma and hemolysate samples, and vitamin E was measured in serum. RESULTS: Anemic dogs (both hemolytic and nonhemolytic) had significantly lower median RBC hemolysate GSH concentrations (3.1 μM [0.4-30.8]) when compared to healthy dogs (7.0 μM [0.5-29.7]; P = .03). Dogs with hemolytic anemia had significantly higher median plasma GSH (7.6 μM [0.4-17.8]) when compared to dogs with nonhemolytic anemia (1.6 μM [0.01-7.1]; P = .04) and healthy dogs (2.8 μM [0.1-29.9]; P < .0001). Reactive oxygen species were detectable in all samples, but there was no difference in ROS or vitamin E between groups. CONCLUSIONS AND CLINICAL IMPORTANCE: Oxidative stress is present in anemic dogs. Derangements in biomarkers of oxidative stress are different in dogs with hemolytic anemia and nonhemolytic anemia.