Induction of human-fetal-membrane remodeling in-vitro by the alpha hemolysin of Escherichia coli

PUCCI MOLINERIS, MELISA; SCHIBERT, FLORENCIA; LIMA, MARÍA; ACCIALINI, PAULA; CANÉ, LUCÍA; PELINSKY, PABLO; FARINA, MARIANA; HERLAX, VANESA

PLACENTA

W B SAUNDERS CO LTD

Año: 2024 vol. 148 p. 59 - 68

0143-4004

Introduction: Almost 80% of urinary tract infections during pregnancy are caused by uropathogenic strains ofEscherichia coli. Alpha-hemolysin, toxin secreted by them, has a fundamental role in this pathology development.Considering that urinary tract infections are related with premature rupture of fetal membranes, we proposed toevaluate the effects that alpha-hemolysin induces on human-fetal-membranes.Methods: Thirteen fetal membranes obtained from elective cesarean sections (>37 weeks) were mounted in atranswell-device generating two independent chambers. To mimic an ascendant-urinary-tract infection, membraneswere incubated with different concentrations of pure alpha-hemolysin from the choriodecidual sideduring 24h. Extensive histological analyses were performed and transepithelial electrical-resistance weredetermined. Cell viability, metalloproteinase activity and cyclooxygenase-2- gene expression was estimated bylactate-dehydrogenase–release assay, zymography and RT-qPCR, respectively. Finally, four fetal membraneswere treated with hemolysin preincubated with polyclonal anti-hemolysin antibodies. Cell viability and metalloproteinaseactivity were monitored.Results: After 24 h of treatment, fetal membranes evidenced a structural damage and a decrease in membraneresistance that progressed as the concentration of alpha hemolysin increased. While the amniotic-epithelial-layerremained practically unaffected, the chorion cells manifested an increase in vacuolization and necrosis. Inaddition, the extracellular matrix exhibited collagen-fiber disorganization, a marked decrease in fiber content,and became thicker in presence of the toxin. Cyclooxigenase-2 expression and metalloproteinase activity were alsohigher in the treated groups than in untreated ones. Finally, a preincubation of hemolysin with specific antibodiesprevented the cytotoxicity on the chorion cells and the increase in metalloproteinase activity.Discussion: Hemolysin induces structural and molecular changes associated with the remodeling of human-fetalmembranesin-vitro.