Proliferative and secretory activity of human umbilical endothelial cells cultivated under various hypoxia conditions

Abstract

In this study, we examined the impact of 3-day hypoxia of different degrees on the viability, proliferation, and secretory activity of endothelial cells from human umbilical vein (HUVEC). A gas mixture of three components was used (%): 1) 10 O₂, 5 CO₂, and 85 Ar; 2) 5 O₂, 5 CO₂, and 80 Ar; and 3) 1 O₂, 5 CO₂, and 94 Ar. Cells cultivated in a CO₂ incubator in atmospheric oxygen (21% O₂) served as control. It was found that 3-day HUVEC cultivation at 1% O₂ increased NO synthesis; enhanced secretion of endothelin-1, IL-6, IL-8, TNF-alpha, sVCAM-1, sE-cadherin, sE-selectin, VEGF-A, and bFGF; and inhibited proliferation. HUVEC cultivated under 10% O₂ and 5% O₂ exhibited the lowest level of basal secretion of these substances and increased proliferative activity. These cells cultivated under conditions of atmospheric oxygen for 3 days displayed activated secretion of NO, IL-6, IL-8, and von Willebrand factor; the activation was higher than at 10% O₂ and 5% CO₂. Thus, the gaseous medium with reduced oxygen content (5%) is a more physiological condition for HUVEC cultivation. An increase in the amount of oxygen up to the atmospheric level causes endotheliocyte activation; the cells exhibit the features of endothelial dysfunction. Oxygen content reduced to 1% induces endothelial dysfunction and reduced proliferative potential.