Endothelial Protein C Receptor Could Contribute to Experimental Malaria-Associated Acute Respiratory Distress Syndrome
Dexamethasone reduces VEGF, TNF, and EPCR, protecting mouse lungs and PMLECs from increased vascular permeability. (a–h) Plasmodium berghei ANKA-infected DBA/2 mice were treated with dexamethasone, and their serum and perfused lungs were analyzed on the 7th day postinfection. (a) The TNF concentration in the serum, (b) EPCR mRNA expression in the lungs, (c) sEPCR concentration in both sera and (d) bronchoalveolar lavage (BAL), and (e) VEGF concentration in BAL were evaluated. (f–g) Evans Blue (EB) accumulation was measured in the lungs and (h) the weight of the lungs was analyzed after perfusion. (i–j) Primary microvascular lung endothelial cells (PMLECs) were treated, or not, with dexamethasone and, subsequently, coincubated with either infected red blood cells (iRBCs) or red blood cells (RBCs). (i) PMLECs were stained for actin microfilaments (gray), and nuclei were stained with Hoechst stain (blue); then, the (j) openings in the interendothelial junctions (OIJ) (indicated by yellow arrows) were compared among all groups. (k) The permeability of dexamethasone-treated PMLECs was related using Evans Blue concentration in a Transwell assay. (l) VEGF levels were measured in these groups. Infected+Dexa: P. berghei ANKA-infected and dexamethasone-treated mice. Graphs: (a, c, d, g, and h) the Mann-Whitney test is representative of (a, d, g, and h) two independent and (c) two grouped experiments; (b, e, and k) the unpaired -test is from (b) two grouped, (e) two independent, and (k) three grouped experiments; (i) the Kruskal-Wallis test is from three grouped experiments; (l) the one-way ANOVA is representative of two independent experiments. Bars represent the (;;). Red dashed lines: noninfected mice.
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