STRUCTURAL ALTERATIONS OF HUMAN CHORIOAMNIOTIC MEMBRANES TREATED WITH ALPHA-HEMOLYSIN OF E.coli

MELISA PUCCI MOLINERIS; HUGO BARBERO; PABLO PELINSKI; VANESA HERLAX; MARÍA S. LIMA; MARIANA FARINA

Modo Virtual

Congreso; Reunión Anual de las Sociedades de Biociencias; 2020

α-hemolysin (HlyA), toxin secreted by uropathogenic strains of Escherichia coli (E.coli), has a fundamental role in urinary tract infections (UTIs). In pregnancy, UTIs are very frequent, being E. coli the etiological agent of almost the 80% of the cases. Considering that UTIs are related with premature rupture of fetal membranes, we proposed to analyze structural tissue changes of human chorioamniotic membranes treated with HlyA in vitro. Methods: Chorioamniotic membranes (n=6) were obtained from deliveries by elective cesarean section (>37 weeks). All included women had normal pregnancies, without evidence of active labor or infection. Membrane explants were mounted and insured to a Transwell device to generate two independent chambers. To simulate an ascending infection, explants were incubated in the chorion-side with 5nM/50nM HlyA during 24h. HlyA was detected by immunohistochemistry and histological signs of damage (like edema, vacuolization, early/late apoptosis, extracellular matrix thickness, and number of fibroblast) were evaluated from paraffin-embedded tissue sections stained with hematoxylin/eosin. Necrosis was tested by LDH release and the transepithelial electrical resistance (TEER) was measured using a Millicell-ERS unit (n=3). Groups were compared using t-, U Mann-Whitney or Chi-squared test as correspond.Results: HlyA interaction with chorioamniotic membranes caused structural alterations and a slight diminish of TEER after 24hs of incubation. The main tissue alterations were observed for the highest toxin concentration tested (50nM HlyA). Epithelial layer remained practically unaltered, while chorion cells showed an increment of vacuolization and necrosis. Extracellular matrix thickness was higher and fibroblast number lower in treated groups compared to control ones. Conclusion: HlyA by itself is capable to introduce structural modifications in human chorioamniotic membranes, suggesting a role of this toxin in premature rupture of membranes.