ROLE OF SCD40L IN THE PATHOGENESIS OF HEMOLYTIC UREMIC SYNDROME (HUS)

ABREY-RECALDE MARIA JIMENA; AMARAL, MM; ALVAREZ, R; ALBERTO, F; MEJIAS MP; RAMOS, M. VICTORIA; FERNÁNDEZ BRANDO, ROMINA J; EXENI R; ALCONCHER, L; PALERMO, MARINA S

Boston

Congreso; 9th International Symposium On Shiga Toxin (Verocytotoxin) Producing Escherichia coli Infections.; 2015

VTEC

Introduction:Shiga-toxin (Stx) induces endothelial damage that leads to plateletactivation. Activated platelets expose CD40L at surface, which is cleaved generatingthe soluble product (sCD40L).sCD40L-CD40 interaction enhances monocyte TissueFactor (TF) expression, contributing to prothrombotic state. Furthermore,oxidative imbalance induced by Stx could enhance sCD40L through plateletactivation.  The aim of this work was todetermine whether sCD40L are elevated during HUS and mediates Monocyte-procoagulantactivity.  Therefore, we evaluated ifantioxidant N-Acetyl-Cisteine(NAC) prevents sCD40L releaseMaterial&Methods:Supernatants from cultureof endothelial cells (E), with or without Stx(S), platelets (P), and NAC were collected. The treatments were: 1:E,2:E+P, 3:E+S, 4:E+S+P, 5:E+S+P+NAC.  sCD40L levels in supernatants and plasma (fromHUS grade1-2 (HUS1-2), HUS grade 3 (HUS3)or healthy controls (HC)), weredetermined by ELISA.Control monocytes were incubated in presence of plasma ofthe same clinical groups depleted or not of sCD40L, and its TF expression wasmeasured by Flow Cytometry Results:sCD40L (ng/ml, MEAN±SEM): Plasma: HC=1.48±0.27, HUS1-2=3.72±0.76*, HUS3=1.48±0.41(*p<0.05). Supernatants: 1=non-detectable(ND), 2=0.05±0,02, 3=ND, 4=1.28±0.39* 5=0.69±0.27(*p<0.05).  HUS1-2 had increasedsCD40L plasma levels.  In accordance with that, supernatant from treatment 4had higher sCD40L levels than treatment 2. NAC (5) was able to prevent sCD40Lrelease. TF expression in Monocytes pre-incubated in plasma from: HC=34±7, HUS1-2=151±36*, HUS1-2D=78±39(*p<0.05) (Mean Fluorescence Intensity, MEAN±SEM). Plasma from HUS1-2 induced higher TF expression than HC plasma. When HUS1-2plasmas were depleted of sCD40L TF expression decreased, suggesting that the enhancingeffect was mediated by sCD40L. Implications: sCD40L is elevated inHUS and could contribute to the prothrombotic state, showing a new mechanism bywhich Platelets participate in HUS pathogenesis. NAC prevents sCD40L releasesuggesting that NACmay be useful in the treatment of HUS.