Impedance-Based Surveillance of Transient Permeability Changes in Coronary Endothelial Monolayers after Exposure to Ionizing Radiation

Abstract

The relative radiation sensitivities of the various compartments of the heart are poorly characterized. Cardiac fibrosis is a common side effect of radiotherapy, suggesting that endothelial barrier function is an important factor in radiation-induced pathology. We employed Electric Cell Substrate Impedance Sensing (ECIS) to assess cytoskeletal rearrangement, permeability changes and endothelial barrier function changes in response to radiation in studies of human coronary arterial endothelial cells (HCAECs). A 5-Gy dose of γ radiation resulted in a significant sixfold transient decrease in transmonolayer resistance 3 h postirradiation (P = 0.001). This decrease in resistance coincided with changes in fluorescent tracer flux (P = 0.05) and display of an actin bundling phenotype. After irradiation, decreases in wound healing (P = 0.03) and micromotion within the monolayer (P = 0.02) were also observed. Time-lapse video studies confirmed that the monolayer is dynamic and showed that cells are extruded from the monolayer at a higher frequency after irradiation. These findings suggest that perturbed endothelial barrier function in the heart can occur at lower doses of γ radiation than previously reported.

The PI3K/Akt/mTOR Pathway Is Implicated in the Premature Senescence of Primary Human Endothelial Cells Exposed to Chronic Radiation

“…It is possible that biological mechanisms responsible for the low-dose-rate effects differ from those of high-dose-rate effects. In radiation-induced CVD, high doses cause overt damage to the myocardium [39] but at low and moderate doses the main target for damage appears to be the endothelium [40]–[42], a cell population typified by a long lifespan, slow proliferation rate and high sensitivity to radiation-induced cell killing. The effects of chronic exposure on endothelial cell function are largely unknown.…”

Chronic Gamma-Irradiation Induces a Dose-Rate-Dependent Pro-inflammatory Response and Associated Loss of Function in Human Umbilical Vein Endothelial Cells

“…At the cellular level, the effects of radiation have been studied with diverse endothelial models and methods with regards to endothelial barrier damage or permeability change (15,16), cytoskeleton disruption (17,18), angiogenic capacity impediment (19,20) and premature senescence (21,22).…”

Transient impedance changes in venous endothelial monolayers as a biological radiation dosimetry response

“…Radiation effects on HUVECs were assessed using electric cell substrate impedance sensing (ECIS) technology. Using this sensitive, continuous bioelectric measurement approach, the laboratory previously described a six-fold decrease in monolayer resistance after wounding and irradiation, observing a statistically significant decrease in resistance after radiation alone [28]. The ECIS instrument passes multiple frequencies of alternating current through gold pads on a planar array affording extremely sensitive, continuous, non-invasive recordings of monolayer resistance [32,33].…”

“…Impedance based measurements of skin, as a simple, rapid, and accessible triage modality, could be of great benefit in a radiation emergency response. It is known that endothelial monolayers prepared from the human coronary endothelium respond to ionizing radiation by changing shape and permeability with relatively early kinetics [28]. Other investigators have observed that small sections of vasculature obtained in biopsy can report systemic pathologies of the donor with good fidelity [29].…”

“…All surfaces were coated with type I collagen (BD, Bedford, MA) and blocked with bovine serum albumin (Sigma, St. Louis, MO) prior to seeding. Cells were maintained in a modified EBM-2 media (Lonza, Rockville, ME) described in earlier work [28].…”