Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, C108

Oral Communications

Uremic serum affects endothelial nanomechanics and expression of ion channels

A. N. Beyer1, V. Cazana-Perez2, B. Hesse1, T. Giraldez2, J. Navarro-Gonzalez3, D. Alvarez de la Rosa2, K. Kusche-Vihrog1

1. Institute of physiology II, University of Münster, Münster, Germany. 2. Universidad de La Laguna, La Laguna, Spain. 3. Servicio de Nefrología, Candelaria, Spain.

Patients with chronic kidney disease (CKD) have a markedly increased incidence of cardiovascular events and cardiovascular disease (CVD) mortality compared with the age-matched general population. The high concentration of circulating uremic toxins in CDK patients leads to vascular inflammatory responses, thereby inducing endothelial dysfunction, which is associated with CVD development and progression. It is postulated that serum, derived from CKD patients (uremic serum), changes the nanomechanical properties of endothelial cells leading to endothelial dysfunction and vascular inflammation. In addition, the influence of CKD on the expression of endothelial ion channels and its potential modification by mineralocorticoid receptor (MR) inhibition was studied which would consequently also affect endothelial cell function. To test this we employed primary human endothelial cells (HUVEC and HAEC) cultured in medium supplemented with 10% pooled sera from either healthy or uremic patients undergoing dialysis. The mechanical stiffness of the outer layer of the cells was monitored using Atomic Force Microscopy (AFM)-based nanoindentation measurements. To obtain a complete profile of ion channel subunit expression, we performed high-throughput qPCR of 92 ion channel genes using a custom-designed Taqman low-density array card. In addition, we characterized the influence of uremic serum on nitric oxide (NO) production. Our data show that uremic serum potently increased the mechanical stiffness of endothelial cells which was abolished by application of the MR-antagonist spironolactone. In addition, uremic serum augments MR expression and induced remodeling of ion channel expression patterns, including increased expression of αENaC, a known transcriptional target of MR that promotes endothelial stiffness and dysfunction. Exposure of HAEC to uremic serum significantly decreased NO production. Our data identify the vascular endothelium as important target of uremic toxins with the MR as possible mediator of uremia-induced endothelial dysfunction. This supports the proposed beneficial effects of MR inhibition during CKD.

Where applicable, experiments conform with Society ethical requirements