Plasma volume and flight duration effects on post-spaceflight soluble adhesion molecules

Area of Science:

• Space physiology
• Cardiovascular research
• Biomarker analysis

Background:

• Spaceflight induces physiological changes affecting cardiovascular health.
• Soluble adhesion molecules play a role in vascular inflammation and endothelial function.

Purpose of the Study:

• To investigate the impact of plasma volume (PV) changes during spaceflight on circulating adhesion markers.
• To determine if flight duration influences these cardiovascular biomarkers.

Main Methods:

• Assessed plasma volume and adhesion markers (sP-selectin, sE-selectin, sICAM-1) in 22 astronauts preflight, post-landing, and postflight.
• Grouped astronauts by mission duration (<8 days vs. >8 days).

Main Results:

• Plasma volume significantly decreased post-landing and increased postflight.
• sICAM-1 and sE-selectin levels decreased post-landing, with sICAM-1 remaining lower postflight.
• Adjusting for PV changes revealed altered sICAM-1 and sE-selectin levels.
• sP-selectin increased post-landing in shorter missions only.
• Flight duration did not significantly affect PV, sICAM-1, or sE-selectin.

Conclusions:

• Spaceflight-induced PV changes lead to dilution of sICAM-1 and sE-selectin.
• These adhesion marker changes are primarily driven by PV shifts, not flight duration.
• sP-selectin response appears to be duration-dependent.