Protective effects of GHRH antagonists against hydrogen peroxide-induced lung endothelial barrier disruption.

Purpose: Growth hormone-releasing hormone (GHRH) is a hypothalamic hormone, which regulates growth hormone release from the anterior pituitary gland. GHRH antagonists (GHRHAnt) are anticancer agents, which also exert robust anti-inflammatory activities in malignancies. GHRHAnt exhibit anti-oxidative and anti-inflammatory effects in vascular endothelial cells, indicating their potential use against disorders related to barrier dysfunction (e.g. sepsis). Herein, we aim to investigate the effects of GHRHAnt against lung endothelial hyperpermeability.

Methods: The in vitro effects of GHRHAnt in HO-induced endothelial barrier dysfunction were investigated in bovine pulmonary artery endothelial cells (BPAEC). Electric cell-substrate impedance sensing (ECIS) was utilized to measure transendothelial resistance, an indicator of barrier function.

Results: Our results demonstrate that GHRHAnt protect against HO-induced endothelial barrier disruption via P53 and cofilin modulation. Both proteins are crucial modulators of vascular integrity. Moreover, GHRHAnt prevent HO - induced decrease in transendothelial resistance.

Conclusions: GHRHAnt represent a promising therapeutic intervention towards diseases related to lung endothelial hyperpermeability, such as acute respiratory distress syndrome - related or not to COVID-19 - and sepsis. Targeted medicine for those potentially lethal disorders does not exist.