Hemolysis contributes to anemia during long-duration space flight

Guy Trudel,Hakim Louati,Timothy Ramsay,Odette Laneuville,Nibras Shahin

doi:10.1038/s41591-021-01637-7

Guy Trudel, Hakim Louati + Show 3 more

Open Access

https://doi.org/10.1038/s41591-021-01637-7

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Journal: Nature Medicine	Publication Date: Jan 1, 2022
Citations: 52	License type: open-access

Affiliation: Ottawa Hospital, University of Ottawa

Abstract

Anemia in astronauts has been noted since the first space missions, but the mechanisms contributing to anemia in space flight have remained unclear. Here, we show that space flight is associated with persistently increased levels of products of hemoglobin degradation, carbon monoxide in alveolar air and iron in serum, in 14 astronauts throughout their 6-month missions onboard the International Space Station. One year after landing, erythrocytic effects persisted, including increased levels of hemolysis, reticulocytosis and hemoglobin. These findings suggest that the destruction of red blood cells, termed hemolysis, is a primary effect of microgravity in space flight and support the hypothesis that the anemia associated with space flight is a hemolytic condition that should be considered in the screening and monitoring of both astronauts and space tourists.

Highlights

Anemia in astronauts has been noted since the first space missions, but the mechanisms contributing to anemia in space flight have remained unclear
Current understanding of space anemia is that the decrease in red blood cell (RBC) constitutes an acute adaptation to major hemodynamic events of cephalad fluid shifts, hemoconcentration and low erythropoietin (EPO) levels upon entering microgravity[1,2]
Astronauts were found to remain mildly hemoconcentrated throughout long-duration mission[3], and epidemiological data showed that the severity, time to recovery and longitudinal effects of postflight anemia were proportional to the time spent in space[4]

Summary

Introduction

Anemia in astronauts has been noted since the first space missions, but the mechanisms contributing to anemia in space flight have remained unclear. We measured hemolysis markers in breath and blood samples from astronauts preflight, four times inflight and up to 1 year after their 6-month missions to the International Space Station (ISS). CO elimination in space over 6 months (average of 46 measures) was increased 54% (95% CI, 39–70) compared to preflight (Fig. 2a; Supplementary Tables 1 and 2).

Results

Conclusion