Figure 1.

Chronic kidney disease patient sera and excess sFlt-1 stiffen endothelial cell cortex. (A) Endothelial stiffness of EA.hy926 cells was measured by atomic force microscopy (AFM) after 24 h of incubation with controls’ and patients’ sera. The values obtained (20–50 values/patient) were grouped according to the stage of CKD (stages three–five), plotted as box and whiskers, and were used for comparison among all three stages and controls (* p < 0.0001). Mean values obtained from each patient (dots) were used for comparison between Total (all patients) and controls (** p = 0.0020). (B) The graphic represents the effect of sFlt-1 neutralization by incubation with a specific antibody followed by immunoprecipitation in protecting cells against patient serum-induced stiffness. Values represent 15–30 measurements/treatments based on two independent experiments. Fetal calf serum (FCS) was used as a reference value (control). (C) Aortae from mice exposed to continuous in vivo administration of recombinant sFlt-1 (300 ng/h; N = 3) or control protein (IgG-Fc, 300 ng/h; N = 3) for three days were isolated and analyzed ex vivo by AFM. All values obtained (20–29 values/mouse) were plotted as box and whiskers and used for comparison between groups. Mean values obtained from individual mice are represented as dots. (D) Dose-response curve of human recombinant sFlt-1 (0.5–2 µg/mL) incubated with EA.hy926 cells for 24 h. Control cells were treated with control protein (2 µg/mL). (E) Endothelial stiffness of primary HUVECs was measured by AFM 24 h after incubation with sFlt-1 or control protein (2 µg/mL). Coincubation with the SB203580 (10 µM), a specific p38 MAPK inhibitor, protected cells from stiffening upon sFlt-1 treatment. Results are expressed as mean ± SEM.