Erythrocyte aggregation and neutrophil function in an aging population

There are limited investigations which have examined the relationship between neutrophil activation and erythrocyte aggregation in older persons. The purpose of the present study was to investigate the relationship between neutrophil activation and erythrocyte aggregation (EA) in an aging population. Twenty-eight male and female subjects were allocated into one of four groups with 7 participants in each group (group 1, 20-29 years; group 2, 30-39 years; group 3, 40-49 years; group 4, 50-59 years). EA was determined using the Myrenne aggregometer. Neutrophil function (respiratory burst and phagocytic activity) was assessed using flow cytometry. EA was found to increase with age. An ANOVA showed a significant (p < 0.05) increase for EA in autologous plasma in group 4 compared to groups 1 and 2. An ANOVA and Pearson's correlation showed that phagocytic activity decreased with age. Furthermore, a positive correlation between stimulated phagocytic activity and erythrocyte aggregability at low shear in 3% dextran-70 solution was observed. The current investigation suggests a decrease in neutrophil phagocytic activity with age and EA was increased with age. Additionally, the current study is novel as it suggests a possible relationship between neutrophil phagocytic activity and erythrocyte aggregability.