The neuropeptide galanin promotes an anti-thrombotic phenotype on endocardial endothelial cells from heart failure patients.

Abstract

Thromboembolic complications are a significant cause of mortality and re-hospitalization in heart failure (HF) patients. One source of thrombi is the ventricular endocardial surface that becomes increasingly pro-thrombotic as HF progresses. Anticoagulation comes with bleeding risks so identifying therapeutic agents for improving cardiac endothelial health are of critical clinical importance. Endocardial endothelial cells are closely apposed to cardiac sympathetic nerves. In HF, cardiac sympathetic nerves are dysregulated and promote disease progression. Whether endocardial endothelial health and function is impacted by sympathetic dysregulation in HF is unknown. Also unexplored is the impact of neuropeptides, such as galanin and neuropeptide Y (NPY), co-released from sympathetic nerve terminals, on endothelial health. In this study we examined the effect of sympathetic nerve-released neurotransmitters and neuropeptides on the procoagulant phenotype of cultured human endocardial endothelial cells from HF patients. As a functional readout of procoagulant state we examined thrombin-mediated von Willebrand factor (vWF) extrusion and multimer expression. We demonstrate that vWF extrusion and multimer expression is promoted by thrombin, that isoproterenol (a beta-adrenergic receptor agonist) augments this effect, whereas co-treatment with the beta-blockers propranolol and carvedilol blocks this effect. We also show that vWF extrusion and multimer expression is attenuated by treatment with the neuropeptide galanin, but not with NPY. Our results are consistent with a protective role of beta-blockers and galanin on endocardial endothelial health in heart failure. Improving endothelial health through galanin therapy is a future clinical application of this study.