Neocytolisis: A space born concept of erythrocyte-removal falsified in the Swiss Alps

Neocytolysis is the preferred destruction of young red blood cells (neocytes) when there are too many erythrocytes. This happens during space flight or when descending after a prolonged sojourn at high altitude. We carried out a prospective study at the Jungfraujoch Research Station (3450 m) with the aim to prove the existence of neocytolysis for the first time. Newly formed erythrocytes from 12 male test persons were marked in Heidelberg (110 m) and during a 19-day stay at 3450 m altitude by glycine labelled with non-radioactive isotopes. The elimination dynamics for erythrocytes produced in normoxia and at high altitude did not differ. Together with changes of reticulocyte counts the concept of neocytolysis could be falsified.