The Release of Soluble Factors Contributing to Endothelial Activation and Damage after Hematopoietic Stem Cell Transplantation Is Not Limited to the Allogeneic Setting and Involves Several Pathogenic Mechanisms

Cell growth and morphological changes. Light micrographs showing EC monlayers grown in the presence of control sera (A) and sera collected from patients in the auto group at day 14 (B) and from patients in the allo group at day 21 (C). The images correspond to semiconfluent monolayers. The arrows point out differences in cell morphology and the presence of detritus in (B) and (C), respectively. These micrographs are representative of 6 different experiments.

Expression of VCAM-1, ICAM-1, and E-selectin on the surface of ECs. Light micrographs (original magnification, ×320 for all micrographs) show EC monolayers grown in the presence of sera from controls (A and D), from patients in the auto group at day 14 (B and E), and from patients in the allo group at day 21 (C and F). Micrographs (D), (E), and (F) correspond to images captured with the epi-polarizing filter to visualize VCAM-1 expression and are representative of 6 different experiments. Bar diagrams represent the density of gold labeling (pixels/μm²; mean ± SEM; n = 6), corresponding to the expression of the adhesion receptors VCAM-1, ICAM-1, and E-selectin in cells grown with sera from patients in the auto group (G) and the allo group (H). ∗P < .05 versus Pre condition.

Adhesion of leukocytes on ECs exposed to blood under flow conditions. Light micrographs (original magnification, ×320 for all micrographs) showing leukocytes (arrows) adhered to ECMs grown in the presence of control sera (A), sera from patients in the auto group at day 14 (B), and sera from patients in the allo group at day 21 (C). The bar diagrams represent data corresponding to the adhesion of leucocytes, expressed as a percentage with respect to the number of ECs (number of leukocytes/100 ECs; mean ± SEM; n = 6) grown with sera from patients in the auto group (D) and the allo group (E). The dotted line represents the mean value for control results. ∗P < .05 versus Pre condition.

Platelet adhesion on ECMs generated by ECs. Light micrographs (original magnification, ×320 for all) show platelet interaction with ECM from cells grown in the presence of control sera (A) and sera from patients in the auto group at day 14 (B) and from those in the allo group at day 21 (C). Images are representative of 6 different experiments. Perfusion experiments were performed with citrated blood at 800 s^-1 for 5 minutes. Bar diagrams represent the percentage of surface covered by platelets (%SC) expressed as mean ± SEM (n = 6 on the ECM generated by EC grown with sera from patients in the auto group (D) and the allo group (E)). The dotted line represents the mean value for control results. ∗P < .05 versus Pre condition ^#P < .05 versus control.

vWF concentrations on ECMs from EC monolayers evaluated by immunocytochemistry using gold staining. The bar diagrams represent the expression of vWF (gold particles/μm²) on ECMs generated by EC monolayers grown in the presence of sera from patients in the auto group (A) and the allo group (B). Values are mean ± SEM (n = 6). ∗P < .05. The dotted line represents the mean value for control results.

Phosphorylation kinetics of p38 MAPK, SAPK/JNK, and Erk 42/44. (A) Phosphorylation kinetics of p38MAPK and SAPK/JNK in cells exposed to control sera and sera from patients in the auto group at day 14 and from patients in the allo group at day 21, for 0 seconds, 30 seconds, and 5 minutes. (B) Phosphorylation kinetics of Erk42/44 after 30-second exposure of cells to the sera samples collected at the different time points, as indicated. Blots showing equal amounts of p38MAPK, SAPK/JNK, and Erk42/44 are presented under each phosphorylated protein. The blots are representative of 6 different experiments.