The flow properties of whole blood under physiological and pathological conditions: Microrheological investigation

Abstract

SummaryUsing a filtration technique for whole blood incorporating filters with a pore diameter of 5 pm, red cell deformability in banked blood was measured over a 6-day period. Whole blood filterability in banked blood fell by approximately 50% within 12 hours, the loss of filterability after 6 days being approximately 98%. The addition of pentoxifylline to ageing banked blood (20 μg pentoxifylline/ml blood) improved filterability, the increase in red cell deformability being statistically significant when blood samples were mixed with pentoxifylline and incubated for 2 1/2 hours at 37°C. This effect is attributed to an increase in erythrocyte ATP levels. Measurement of red cell deformability in 29 clinically healthy subjects, taking into account the risk factors ‘cigarette smoking’ and ‘oral contraceptives’, revealed a significant reduction in red cell deformability in male smokers by comparison with male non-smokers (p < 0.001). Similarly, red cell deformability in all male and female smokers was reduced by comparison with all male and female non-smokers (p < 0.05). The authors discuss the significance of red cell deformability in smokers as a factor in microcirculatory impairment with consequences for the development of vascular disease.