Absence of neocytolysis in humans returning from a 3‐week high‐altitude sojourn
Autor: | Laura Hertz, Carsten Lundby, Greta Simionato, Steffen M. Recktenwald, Anna Bogdanova, Heimo Mairbäurl, Silvia Rudloff, Anja Sander, Giampaolo Minetti, Lars Kaestner, Sebastian Fried, Thomas Haider, Asya Makhro, Larissa Schäfer, Marie Klein, Elena Seiler, Christian Borsch, Simone Fenk, Ankie van Cromvoirt, Hugo H. Marti |
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Přispěvatelé: | University of Zurich, Mairbäurl, Heimo |
Rok vydání: | 2021 |
Předmět: |
0301 basic medicine
medicine.medical_specialty Physiology Chemistry 1314 Physiology 030204 cardiovascular system & hematology Effects of high altitude on humans 10081 Institute of Veterinary Physiology Haemolysis Acclimatization 03 medical and health sciences 030104 developmental biology 0302 clinical medicine medicine.anatomical_structure Endocrinology Altitude Reticulocyte Internal medicine medicine 570 Life sciences biology Erythropoiesis Ingestion Neocytolysis |
Zdroj: | Acta Physiologica. |
ISSN: | 1748-1716 1748-1708 |
Popis: | Aims Total haemoglobin mass (tot-Hb) increases during high-altitude acclimatization. Normalization of tot-Hb upon descent is thought to occur via neocytolysis, the selective destruction of newly formed erythrocytes. Because convincing experimental proof of neocytolysis is lacking, we performed a prospective study on erythrocyte survival after a stay at the Jungfraujoch Research Station (JFJRS; 3450 m). Methods Newly formed erythrocytes of 12 male subjects (mean age 23.3 years) were age cohort labelled in normoxia (110 m) and during a 19-day high-altitude sojourn by ingestion of 13 C2- and 15 N-labelled glycine respectively. Elimination dynamics for erythrocytes produced in normoxia and at high altitude were measured by isotope ratio mass spectrometry of haem, by determining tot-Hb, reticulocyte counts, erythrocyte membrane protein 4.1a/4.1b ratio and by mathematical modelling. Results Tot-Hb increased by 4.7% ± 2.7% at high altitude and returned to pre-altitude values within 11 days after descent. Elimination of 13 C- (normoxia) and 15 N- (high altitude) labelled erythrocytes was not different. Erythropoietin levels and counts of CD71-positive reticulocytes decreased rapidly after descent. The band 4.1a/4.1b ratio decreased at altitude and remained low for 3-4 days after descent and normalized slowly. There was no indication of haemolysis. Conclusion We confirm a rapid normalization of tot-Hb upon descent. Based on the lack of accelerated removal of age cohorts of erythrocytes labelled at high altitude, on patterns of changes in reticulocyte counts and of the band 4.1a/4.1b ratio and on modelling, this decrease did not occur via neocytolysis, but by a reduced rate of erythropoiesis along with normal clearance of senescent erythrocytes. |
Databáze: | OpenAIRE |
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