Endothelial cell migration was impaired by irradiation-induced inhibition of SHP-2 in radiotherapy: an in vitro study

Hemodynamic Flow-Induced Mechanotransduction Signaling Influences the Radiation Response of the Vascular Endothelium

Hemodynamic shear stress is defined as the physical force exerted by the continuous flow of blood in the vascular system. Endothelial cells, which line the inner layer of blood vessels, sense this physiological force through mechanotransduction signaling and adapt to maintain structural and functional homeostasis. Hemodynamic flow, shear stress and mechanotransduction signaling are, therefore, an integral part of endothelial pathophysiology. Although this is a well-established concept in the cardiovascular field, it is largely dismissed in studies aimed at understanding radiation injury to the endothelium and subsequent cardiovascular complications. We and others have reported on the differential response of the endothelium when the cells are under hemodynamic flow shear compared with static culture. Further, we have demonstrated significant differences in the gene expression of static versus shear-stressed irradiated cells in four key pathways, reinforcing the importance of shear stress in understanding radiation injury of the endothelium. This article further emphasizes the influence of hemodynamic shear stress and the associated mechanotransduction signaling on physiological functioning of the vascular endothelium and underscores its significance in understanding radiation injury to the vasculature and associated cardiac complications. Studies of radiation effect on endothelial biology and its implication on cardiotoxicity and vascular complications thus far have failed to highlight the significance of these factors. Factoring in these integral parts of the endothelium will enhance our understanding of the contribution of the endothelium to radiation biology. Without such information, the current approaches to studying radiation-induced injury to the endothelium and its consequences in health and disease are limited.

Understanding the Pathophysiology and Challenges of Development of Medical Countermeasures for Radiation-Induced Vascular/Endothelial Cell Injuries: Report of a NIAID Workshop, August 20, 2015

After the events of September 11, 2001, a decade of research on the development of medical countermeasures (MCMs) to treat victims of a radiological incident has yielded two FDA-approved agents to mitigate acute radiation syndrome. These licensed agents specifically target the mitigation of radiation-induced neutropenia and infection potential, while the ramifications of the exposure event in a public health emergency incident could include the entire body, causing additional acute and/or delayed organ/tissue injuries. Anecdotal data as well as recent findings from both radiation accident survivors and animal experiments implicate radiation-induced injury or dysfunction of the vascular endothelium leading to tissue and organ injuries. There are significant gaps in our understanding of the disease processes and progression, as well as the optimum approaches to develop medical countermeasures to mitigate radiation vascular injury. To address this issue, the Radiation and Nuclear Countermeasures Program of the National Institute of Allergy and Infectious Diseases (NIAID) organized a one-day workshop to examine the current state of the science in radiation-induced vascular injuries and organ dysfunction, the natural history of the pathophysiology and the product development maturity of potential medical countermeasures to treat these injuries. Meeting presentations were followed by a NIAID-led open discussion among academic investigators, industry researchers and government agency representatives. This article provides a summary of these presentations and subsequent discussion from the workshop.

Epithelial wound healing on keratin film, amniotic membrane and polystyrene in vitro

PURPOSE

Corneal epithelial wound healing is a major issue in ocular surface (OS) reconstruction. Aim of this study was to evaluate parameters of epithelial wound healing in vitro on transparent keratin films (KFs) derived from human hair in comparison with amniotic membrane (AM) and polystyrene.

MATERIALS AND METHODS

The human corneal epithelial cell line (HCE-T) was expanded on KF, AM and commercially available 24-well polystyrene cell culture plates in vitro to compare cell proliferation, migration and attachment by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, scratch-wound healing and adhesion assay. Cells cultured on KF and AM at an air-liquid interface for 14 d were stained with hematoxylin and eosin for histology.

RESULTS

The highest proliferation of HCE-T cells was observed on polystyrene at all time points (p < 0.05). At a seeding density of 5 × 10(3) cells/well, no difference in proliferation was found between AM and KF after 24 h and 72 h (p = 0.582 and p = 0.066), while higher proliferation was observed on AM compared to KF after 48 h (p = 0.005). At a seeding density of 1 × 10(4) cells/well, no difference was found between AM and KF after 24 h (p = 0.252), while higher proliferation was observed on AM compared to KF after 48 h and 72 h (p = 0.001 and p = 0.003). The significantly fastest cell migration was observed on polystyrene at all time points (p < 0.01). Cell migration was significantly higher on KF compared to AM at 48 h (p < 0.05). After 30 min, there were significantly more cells attached to AM compared to polystyrene and KF (p = 0.032 and p = 0.001). No significant difference in cell attachment was observed between KF and polystyrene (p = 0.147). Histology demonstrated that HCE-T cells cultured on KF and AM at an air-liquid interface for 14 d form a multilayered epithelium similar to normal human corneal epithelium.

CONCLUSION

Transparent KFs derived from human hair support proliferation, migration, adhesion and differentiation of HCE-T cells in vitro. Therefore, it could be a promising alternative to AM for OS reconstruction.