Editorial: Red cell ageing and death.

To obtain red cell populations of increasing mean age erythropoiesis was arrested through continuous actinomycin treatment or maintained transfusion polycythemia in mice and rats respectively. The parameters studied included cell indices, enzyme activities and rheological characteristics. Further, the life-span of aged cells was compared to normal, and the sequestration site was determined. Mice erythrocytes, like those of rats, exerienced a continuous decrease in MCV1, an early rise in MCHC, and late MCH reduction. In ageing rat erythrocytes the activities of HK, GR and 6-PGD did not fall below the normal range during the first 9 tenths of the potential life-span. On the other hand, a borderline reduction of PK activity was found, and the activity of G-6PD underwent a steady though unimpressive decrease to 70% of the physiological average. Aged erythrocytes, forced through 15-mum capillaries differed in apparent viscosity from reticulocytes and normal cells by a factor of 1.31 and 1.16, respectively. Destruction of senescent cells was predominantly confined to the spleen, and prolonged erythrocyte survival followed splenectomy.