Endothelial cell subpopulations in vitro: cell volume, cell cycle, and radiosensitivity

Area of Science:

• Cell Biology
• Radiation Biology
• Vascular Biology

Background:

• Vascular endothelial cells (EC) are crucial targets for radiation and oxidative stress.
• Understanding EC responses to radiation is vital for clinical applications.
• Cytotoxic responses of EC subpopulations may influence overall endothelial damage.

Purpose of the Study:

• To investigate the differential cytotoxic responses of vascular endothelial cell (EC) subpopulations to irradiation.
• To determine if cell volume and cell cycle position influence EC radioresistance.
• To correlate cell cycle phase with acute cell survival and proliferative capacity after gamma irradiation.

Main Methods:

• Bovine aortic EC were cultured and separated into subpopulations based on cell volume using centrifugal elutriation.
• Flow cytometry was employed to analyze cell volume, cell cycle distribution, and DNA content.
• Cytotoxic indexes for acute cell survival and proliferative capacity were assessed after gamma irradiation (0-10 Gy).

Main Results:

• Cell volume correlated with cell cycle phase: smaller EC were in G1, larger EC in S or G2M phases.
• Cell cycle phase did not affect acute cell loss but significantly impacted proliferative capacity post-irradiation (P < 0.01).
• Radioresistance increased with cell cycle progression: G1 < early S < middle S < late S + G2M phases, with D0 values ranging from 110 to 180 cGy.

Conclusions:

• Vascular endothelial cell (EC) subpopulations exhibit distinct radioresistance profiles.
• Cell cycle phase influences the proliferative capacity and radioresistance of EC.
• Findings suggest an age-related radiation response in nonmalignant differentiated endothelial cells.