[Evaluation of age-related changes of erythrocyte filtration]

In two groups of subjects (young and elderly), the red blood cell (RBC) deformability was examined determining the filtration time by means of two different methods (filtration of whole blood and filtration of RBC suspension with hematocrit adjusted at 20%, respectively). In addition, the DFE (Debit de filtration erythrocytaire), an indirect index of capillary blood flow, was mathematically derived. Since the filtration times appear to be positively correlated with age, it is conceivable that in the elderly, erythrocytes are less deformable than in the young, and that this change may impair both capillary blood flow and tissue oxygen delivery; this alteration is further emphasized when the relationship between whole blood filtration time and hematocrit is taken into account.