title: Short term effects of gamma radiation on endothelial barrier function: uncoupling of PECAM-1.
abstract: A limiting factor in the treatment of cancer with radiotherapy is the damage to surrounding normal tissue, particularly the vasculature. Vessel pathologies are a major feature of the side effects of radiotherapy and little is known about early events that could initiate subsequent diseases. We tested the hypothesis that gamma radiation has early damaging effects on the human endothelial barrier. Two models were used; Human Brain Microcapillary Endothelial Cells (HBMEC), and Human Umbilical Vein Endothelial Cells (HUVEC). Endpoints included Trans-Endothelial Electrical Resistance (TEER), barrier permeability to 10 kDa and 70 kDa tracer molecules, and the localization of F-actin, and junction proteins and the Platelet Endothelial Cell Adhesion Molecule (PECAM-1). Radiation induced a rapid and transient decrease in TEER at 3 h, with effects also seen at the radiotherapy doses. This dip in resistance correlated to the transient loss of PECAM-1 in discrete areas where cells often detached from the monolayer leaving gaps. Redistribution of PECAM-1 was also seen in 3-D human tissue models. By 6 h, the remaining cells had migrated to reseal the barrier, coincident with TEER returning to control levels. Resealed monolayers contained fewer cells per unit area and their barrier function was weakened as evidenced by an increased permeability over 24 h. This is the first demonstration of a transient and rapid effect of gamma radiation on human endothelial barriers that involves cell detachment and the loss of PECAM-1. Considering the association of cell adhesion molecules with vasculopathies, such an effect has the potential to be clinically relevant to the longer-term effects of radiotherapy.
authors.affiliation: Center for Radiological Research, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA. pms2144@columbia.edu
authors.forename: Preety
authors.initials: P
authors.lastname: Sharma
authors.forename: Thomas
authors.initials: T
authors.lastname: Templin
authors.forename: Peter
authors.initials: P
authors.lastname: Grabham
mesh_terms: D000199:Actins / Q000032:analysis; D002199:Capillary Permeability / Q000528:radiation effects*; D002448:Cell Adhesion / Q000528:radiation effects; D015815:Cell Adhesion Molecules / Q000032:analysis; D018929:Cell Culture Techniques / Q000379:methods; D002478:Cells, Cultured / Q000737:chemistry / Q000502:physiology / Q000528:radiation effects; D003599:Cytoskeleton / Q000648:ultrastructure; D017097:Electric Impedance; D042783:Endothelial Cells / Q000737:chemistry / Q000502:physiology / Q000528:radiation effects; D004730:Endothelium, Vascular / Q000737:chemistry / Q000502:physiology / Q000528:radiation effects*; D005720:Gamma Rays / Q000009:adverse effects*; D061307:Human Umbilical Vein Endothelial Cells / Q000737:chemistry / Q000502:physiology / Q000528:radiation effects; D006801:Humans; D007365:Intercellular Junctions / Q000528:radiation effects / Q000648:ultrastructure; D055806:Microvessels / Q000166:cytology; D009940:Organoids / Q000737:chemistry / Q000502:physiology / Q000528:radiation effects; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis*; D011832:Radiation Injuries / Q000209:etiology*
chemical_list: D000199:Actins; D015815:Cell Adhesion Molecules; D019408:Platelet Endothelial Cell Adhesion Molecule-1