Relationship between the age of human erythrocytes and their osmotic resistance: a basis for separating young and old erythrocytes.

A study has been made of the effect of age on the susceptibility of mature human erythrocytes to hemolysis in hypotonic media. The alterations in osmotic fragility associated with red cell aging are pertinent to the relationship between cellular senescence and the maintenance of cell mambrane integrity. In addition, differences in osmotic resistance between young and old erythrocytes could provide a basis for separating the whole red cell population into fractions of differing mean cell age. A method for achieving such a separation would permit investigation of biochemical changes associated with in sivo aging of erythrocytes. On the basis of experiments with red cells of dogs, Cruz, Hahn, Bale and Balfour (2) and Stewart, Stewart, Izzo and Young (3) concluded that young canine erythrocytes were less resistant to hypotonic lysis than older cells. Recent evidence suggests that the young erythrocytes of rabbit (4, 5), rat and (6) and man (7) are more resistant to hemolysis in hypotonic media than are older cells. In the present investigation, Fe59 has been employed to label, in vivo, erythrocytes of a limited age (8-11). It has been found that graded osmotic hemolysis may achieve a separation of red cells into fractions of relatively young and old mean cell ages. The young human erythrocytes are more resistant to hemolysis in hypotonic media than older cells.