Figure 4. Chronic (24 hours), but not acute (30 min) salt challenge damages the eGC.

(A) Endothelial cells (EA.hy926) were incubated in low and high Na⁺ for 24 h and heparan sulfates (HS) were stained and quantified with a specific anti-HS antibody and secondary Quantum Dot (QD) antibody. High Na⁺ decreased HS, compared to low Na⁺, application of spironoloctone (spiro) prevented the high Na⁺ effect (N = 3; n = 60, * indicates p ≤ 0.05). (B) Representative images of QD-mediated stainings of HS in endothelial cells. (C) Levels of syndecan-1 were detected in the supernatant of endothelial cells after stimulation with Na⁺ using an ELISA. Shedding of the eGC (high syndecan-1 levels) was observed only in chronically (24 h) treated endothelial cells but not with acute (30 min) incubation in high Na⁺ (N = 6; * indicates p ≤ 0.05). (D) The NO release of endothelial cells was measured as marker for endothelial function. Spironolactone increased the endothelial production of NO, indicating improvement of vascular function (N = 4; * indicates p ≤ 0.05).