Biochemical and hematologic changes after short-term space flight

Area of Science:

• Space medicine
• Human physiology in space
• Clinical laboratory science

Background:

• Understanding physiological adaptations to spaceflight is crucial for astronaut health.
• Previous studies on Skylab missions provided insights into long-duration spaceflight effects.
• Space Shuttle missions offer opportunities to study shorter-duration spaceflight impacts.

Purpose of the Study:

• To compare clinical laboratory data from astronauts after short-term Space Shuttle flights with data from longer Skylab missions.
• To identify specific biomarkers and physiological responses affected by spaceflight duration.
• To investigate the influence of countermeasures and mission specifics on astronaut health.

Main Methods:

• Analysis of astronaut blood samples collected pre- and post-flight.
• Statistical comparison using paired t-test and Wilcoxon signed-rank test.
• Comparison of Space Shuttle (approx. 6 days) and Skylab (approx. 28, 59, 84 days) flight data.

Main Results:

• Angiotensin I and aldosterone elevated post-Shuttle; angiotensin I response delayed post-Skylab.
• Magnesium and uric acid decreased post-Shuttle and Skylab; serum calcium unchanged post-Shuttle.
• Creatine phosphokinase reduced post-Shuttle (likely due to exercise countermeasures), but not post-Skylab.
• Red blood cell concentration increased post-Shuttle, decreased post-Skylab; reticulocyte count decreased in both.
• Total cholesterol unchanged, LDL-C increased, HDL-C decreased post-Shuttle; serum ferritin and platelets elevated post-Shuttle.

Conclusions:

• Spaceflight duration significantly influences hormonal and hematological parameters.
• Reduced red blood cell mass appears linked to suppressed production rather than increased destruction.
• Differences in responses between short- and long-term flights may be attributed to mission duration, countermeasures, spacecraft, and landing procedures.