title: Dose-dependent endothelial cell growth and stiffening by aldosterone: endothelial protection by eplerenone.
abstract: BACKGROUND
  Aldosterone at high concentrations causes an expansion of apical surface area and volume of cultured endothelial cells. These morphological changes are associated with endothelial cell stiffening. Here, we tested the hypothesis that the aforementioned aldosterone actions are confined to aldosterone concentrations within the pathophysiological range. Moreover, we investigated whether endothelial cells of venous and arterial origin respond similarly to aldosterone and whether the new aldosterone antagonist eplerenone effectively prevents endothelial cell growth and stiffening.
  
  
  METHODS
  We used an endothelial cell line of venous origin (EAHy 926) and primary cultures of human coronary artery endothelial cells (HCAEC). Cells were incubated for 72 h with aldosterone at concentrations of 0.1, 1, 10 and 100 nmol/l. Eplerenone was added at a concentration of 2 micromol/l. Applying atomic force microscopy, we scanned cell layers under fixed and living conditions, allowing measurement of endothelial cell apical surface, volume and cellular stiffness.
  
  
  RESULTS
  Aldosterone had comparable effects on EAHy 926 and HCAEC. In EAHy 926, the apical surface increased dose dependently by up to 72 +/- 5% and cell volume by up to 36 +/- 5%. In HCAEC, the maximum increase of apical surface was 78 +/- 6% and maximum cell volume expansion was 58 +/- 6%. Furthermore, aldosterone increased endothelial cell stiffness from 1.47 +/- 0.08 kPa up to 3.95 +/- 0.15 kPa in EAHy 926, and from 1.64 +/- 0.13 kPa up to 4.31 +/- 0.13 kPa in HCAEC. Physiological aldosterone concentrations had no effect, but starting at 1 nmol/l, corresponding to the low pathophysiological range, substantial cell alterations emerged. Eplerenone, at a therapeutic concentration, prevented the observed actions of aldosterone.
  
  
  CONCLUSIONS
  Aldosterone-induced endothelial cell growth and stiffening in vitro begins with concentrations in the low pathophysiological range. The preventive action of eplerenone indicates that the endothelium could be a major target of this drug in vivo.
authors.affiliation: Department of Internal Medicine D, University of Muenster, Germany.
authors.forename: Uta
authors.initials: U
authors.lastname: Hillebrand
authors.forename: Hermann
authors.initials: H
authors.lastname: Schillers
authors.forename: Christoph
authors.initials: C
authors.lastname: Riethmüller
authors.forename: Christian
authors.initials: C
authors.lastname: Stock
authors.forename: Marianne
authors.initials: M
authors.lastname: Wilhelmi
authors.forename: Hans
authors.initials: H
authors.lastname: Oberleithner
authors.forename: Martin
authors.initials: M
authors.lastname: Hausberg
mesh_terms: D000450:Aldosterone / Q000502:physiology*; D049108:Cell Enlargement / Q000187:drug effects*; D002460:Cell Line; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004548:Elasticity / Q000187:drug effects; D042783:Endothelial Cells / Q000187:drug effects* / Q000502:physiology; D000077545:Eplerenone; D006801:Humans; D066298:In Vitro Techniques; D018625:Microscopy, Atomic Force; D000451:Mineralocorticoid Receptor Antagonists / Q000494:pharmacology; D013148:Spironolactone / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D000451:Mineralocorticoid Receptor Antagonists; D013148:Spironolactone; D000450:Aldosterone; D000077545:Eplerenone