RELEVANCE OF PLATELETS IN NETS-INDUCED ENDOTHELIAL DAMAGE IN HEMOLYTIC UREMIC SYNDROME.

LANDONI VERÓNICA INÈS; NAHUEL RODRIGUEZ-RODRIGUES; LUIS A CASTILLO; AGOSTINA CARESTIA; DE CAMPOS NEBEL M; DAIANA MARTIRE-GRECO; FEDERICO BIRNBERG WEISS; SCHATTNER M; PABLO SCHIERLOH,; FERNÁNDEZ, GC

Mar del Plata

Congreso; Reinion de Biociencias; 2017

Hemolytic Uremic Syndrome (HUS) is the most common cause ofpediatric renal failure. Linked to Gram (-) Shiga toxin-producing (Stx)infections, lipopolysaccharide (LPS) and neutrophils (PMN) canpotentiate the disease. Since endothelial damage is characteristicof HUS, PMN-platelet (Plts) interaction in the context of Stx couldpromote netosis causing endothelial damage. We have shown thatStx2 increases netosis induced by LPS-treated Plts and endothelialcytotoxicity in vitro. The aim of this work is to study in detail this phenomenonand determine the relevance of netosis in a murine modelof HUS. We determined in vitro by FACS that Stx2 stimulation ofLPS-treated Plts increased the formation of PMN-Plts mixed aggregates(% CD11b+CD61+ p≤0,05) and increased the activation ofboth PMN (CD11b p≤0,05) and Plts (P-selectin p≤0,05). Additionally,the increased netosis promoted by Stx2 stimulation of LPS-treatedPlts was dependent on the PMN-Plts-mediated P-selectin junction.In order to corroborate in vitro findings, mice administrated with LPSand Stx2 showed an increased % of PMN-Plts blood aggregates(%Gr1+CD61+ p≤0.05) in LPS+Stx2 treated mice. Also the NETsin this group were increased measured using an ELISA kit (PMNElastase-DNA levels p≤0.05).Correlating with this, endothelial damagewas higher in LPS+Stx2 treated mice (von Willebrand Factor,vWF levels in plasma p≤0.05). NETs were digested and levels ofElastase-DNA decreased correlating with vWF diminution. Finally, inorder to evaluate the role of circulating Plts mice were depleted ofPlts. We observed in LPS+Stx2 mice without Plts that, both netosis(Elastase-DNA levels p≤0.05) and endothelial damage levels (vWFp≤0.05) decreased compared to LPS+Stx2. These results demonstratethe relevance of LPS+Stx2 induced netosis on vascular damageand the fundamental role of Plts in this phenomenon.Key-words: HUS, platelets, NETs, endothelial damage