Photodynamic treatment of human endothelial cells promotes the adherence of neutrophils in vitro.

The effects of photodynamic treatment (PDT) on venules include vascular leakage accompanied by oedema formation, vasoconstriction and blood flow stasis. The goal of this study was to gain insight into the mechanism underlying these vascular events by studying one of the earliest observations after PDT, granulocyte adhesion, in an in vitro model. For this purpose human umbilical vein endothelial cells (HUVECs) preincubated with Photofrin II (PII) were illuminated with red light and incubated with neutrophils.