Growth hormone-releasing hormone antagonists counteract interferon-γ - induced barrier dysfunction in bovine and human endothelial cells.

GHRH regulates the secretion of GH from the anterior pituitary gland. An emerging body of evidence suggests that the activities of that neuropeptide are not limited to the GH/IGF-I axis, but they expand towards the mediation of inflammatory processes. GHRHAnt were developed to oppose the activities of GHRH in malignancies, and have been associated with strong anti-inflammatory and anti-oxidative effects in a diverse variety of tissues, including the lungs. In the present study we report that GHRHAnt oppose interferon-γ - induced paracellular hyperpermeability and reactive oxygen species generation in bovine and human pulmonary endothelial cells; and suppress interferon-γ - triggered STAT3, cofilin and ERK1/2 activation. Our observations substantiate previous findings on the protective effects of GHRHAnt in endothelial inflammation and barrier break-down.

Growth hormone - releasing hormone in the immune system.

GHRH is a neuropeptide associated with a diverse variety of activities in human physiology and immune responses. The present study reviews the latest information on the involvement of GHRH in the immune system and inflammation, suggesting that GHRH antagonists may deliver a new therapeutic possibility in disorders related to immune system dysfunction and inflammation.

Protective Activities of Growth Hormone-Releasing Hormone Antagonists against Toxin-Induced Endothelial Injury.

GHRH regulates the secretion of GH from the anterior pituitary gland, previously associated with cancer progression and inflammation. An emerging body of evidence suggests that GHRHAnt support endothelial barrier function, but the mechanisms mediating these events are not completely understood. In the present study, it is demonstrated that the GHRHAnt JV-1-36 counteracts barrier dysfunction due to LPS or LTA treatment in HUVECs, utilizing the Dextran-FITC assay. Moreover, it is shown in BPAECs that these bacterial toxins increase ROS generation, and that this effect is counteracted by JV-1-36, which reinstates the redox balance. The possible involvement of NEK2 in the beneficial activities of GHRHAnt in IFN-γ- and LPS-triggered hyperpermeability was also assessed, since that kinase is involved in inflammatory responses. NEK2 was increased in the inflamed cells, and JV-1-36 counteracted those endothelial events. Our data support the beneficial effects of GHRHAnt in toxin-induced endothelial injury.

Octreotide protects against LPS-induced endothelial cell and lung injury.

Growth hormone (GH) is a crucial regulator of growth, cell reproduction, and regeneration; and it is controlled by growth hormone-releasing hormone (GHRH) and somatostatin. Lipopolysaccharides (LPS) can compromise endothelial function, leading to increased inflammation and vascular leak. Octreotide (OCT) is an FDA-approved synthetic somatostatin analog (SSA) used to treat acromegaly and neuroendocrine tumors. The present study investigates the effects of OCT on LPS-induced injury in bovine and human lung endothelial cells, as well as in mouse lungs. Our in vitro observations suggest that OCT effectively counteracts LPS-induced endothelial leak, inflammation, and reactive oxygen species (ROS) generation. Furthermore, OCT reduces bronchoalveolar lavage fluid (BALF) protein concentration in an experimental model of Acute Lung Injury (ALI). Our study suggests that OCT mitigates LPS-induced endothelial cell and lung injury, suggesting that it may represent an exciting therapeutic possibility in diseases related to barrier dysfunction.

Protective effects of growth hormone - releasing hormone antagonists in the lungs of septic mice.

Growth hormone-releasing hormone antagonists (GHRHAnt) have been associated with antitumor and antioxidative activities. The present study investigates for the first time the effects of those compounds towards pro-inflammatory cytokine expression in a murine model of cecal ligation and puncture (CLP) - induced sepsis. The results indicate that GHRHAnt JV-1-36 significantly suppressed IL-1α, IL-6, and pSTAT3 activation in septic lungs. Moreover, GHRHAnt treatment reduced bronchoalveolar lavage fluid (BALF) protein concentration, suggesting a protective effect of that compound in sepsis-induced lung edema. Based on those findings, it is suggested that GHRHAnt may represent an exciting new therapeutic possibility in sepsis-induced endotoxemia and lung injury.