title: Involvement of hypoxia and inflammation in early pregnancy loss mediated by Shiga toxin type 2.
abstract: BACKGROUND
  Symptomatic or asymptomatic Shiga toxin producing Escherichia coli (STEC) infections during early pregnancy may cause maternal or fetal damage mediated by Shiga toxin type 2 (Stx2). The aim of this study is to elucidate the mechanisms responsible for early pregnancy loss in rats treated with Stx2.
  
  
  METHODS
  Sprague Dawley pregnant rats were intraperitoneally injected at day 8 of gestation with a sublethal dose (0.5 ng of Stx2/g of total body weight, 250 μl) of purified Stx2. Control rats were injected with the same volume of PBS. The expression of globotriaosylceramide (Gb3) glycosphingolipid receptor for Stx2 was evaluated by thin-layer chromatography (TLC). Regions of hypoxia in decidual tissue were determined by pimonidazole immunohistochemistry and vascular endothelial growth factor (VEGF) expression by Western blot and immunohistochemistry. Tumor necrosis factor-alpha (TNF-α) levels in serum and decidual tissue were evaluated by ELISA. Serum progesterone levels were determined by RIA.
  
  
  RESULTS
  Decidual tissue from both, control and Stx2-treated rats showed similar expression of Gb3 receptor. Intrauterine growth restriction was observed in Stx2-treated rats, associated with hypoxia and an increase of decidual TNF-α levels. Decrease of serum progesterone levels and decidual VEGF expression were also demonstrated.
  
  
  CONCLUSIONS
  Our findings indicate that Stx2 reaches the uteroplacental unit, binds Gb3 and triggers damage in decidual tissue. Poor oxygen supply accompanied with damage in the uteroplacental unit and inflammation could be responsible for the early pregnancy loss. Decrease in the pregnancy protective factors, serum progesterone and local VEGF, may contribute to the pregnancy loss.
authors.affiliation: Laboratorio de Fisiopatogenia, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: F
authors.initials: F
authors.lastname: Sacerdoti
authors.affiliation: Laboratorio de Fisiopatogenia, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: M M
authors.initials: MM
authors.lastname: Amaral
authors.affiliation: CEFYBO-CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: J
authors.initials: J
authors.lastname: Aisemberg
authors.affiliation: CEFYBO-CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: C B
authors.initials: CB
authors.lastname: Cymeryng
authors.affiliation: CEFYBO-CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: A M
authors.initials: AM
authors.lastname: Franchi
authors.affiliation: Laboratorio de Fisiopatogenia, Departamento de Fisiología, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina. Electronic address: ibarra@fmed.uba.ar.
authors.forename: C
authors.initials: C
authors.lastname: Ibarra
mesh_terms: D000022:Abortion, Spontaneous / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D005260:Female; D000860:Hypoxia / Q000378:metabolism / Q000473:pathology*; D007249:Inflammation / Q000378:metabolism / Q000473:pathology*; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D022641:Shiga Toxin 2; D014281:Trihexosylceramides / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D022641:Shiga Toxin 2; D014281:Trihexosylceramides; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; C018549:globotriaosylceramide
keywords: Hypoxia; Inflammation; Pregnancy loss; STEC; Stx2