Background: Radiation-induced wound healing complications represent an important clinical problem. Microvascular compromise is an important component of its pathogenesis and the microvascular endothelial cell is the key representative affected at the cellular level.
Material and methods: Human dermal microvascular endothelial cells (HDMEC) were cultured and irradiated with doses of 2 to 12 Gy. Cell density was determined 48 h after radiation using a semi-automated cell counting system. Levels of interleukin-6 (IL-6), basic fibroblast growth factor (FGF), intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in the supernatants of HDMEC were determined by polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). Non irradiated HDMEC were used as controls.
Results: Cell density was significantly impaired in irradiated cells compared to non irradiated controls. Radiation resulted in significant elevation of levels of IL-6, FGF, ICAM-1 and VCAM-1 in the supernatants of HDMEC in a dose dependent manner.
Conclusion: The inflammatory response observed clinically after radiation seems to correlate with elevated expression of cytokines and adhesion molecules by microvascula endothelial cells. The model of HDMEC documents the impairment of microcirculation. These in vitro changes may enhance our understanding of the pathomechanisms leading to radiation-induced vasculitis and associated wound healing problems.
Keywords: Endothelial cells; adhesion molecules; cytokines; endothelial dysfunction; growth factors; radiation therapy.