Properties and characterization of vesicles released by young and old human red cells.

We have presently demonstrated morphologic differences between young and senescent red cells following 18 h of metabolic depletion in vitro. Young and old red cells both form echinocytes, whereas only young cells demonstrated myelin forms or microspheres. Furthermore, vesicles were released in greater quantities into the cell-free supernatant from young cells. Isolated vesicles from both young and old red cells contained lipids, intrinsic membrane proteins (especially band 3), and haemoglobin, and they were also enriched in acetylcholinesterase (AChE). Young cells produced more vesicles than old cells but the composition of the low density vesicles was similar except that haemoglobin-spectrin complex was found exclusively in vesicles from young cells. Oxidation of young red cells prior to metabolic depletion prevented both myelin formation and vesicle release.