title: Decidual GM-CSF is a critical common intermediate necessary for thrombin and TNF induced in-vitro fetal membrane weakening.
abstract: BACKGROUND
  Inflammation/infection and decidual bleeding/abruption are highly associated with pPROM. As no animal model for pPROM exists, we have developed an in-vitro model system for the study of human fetal membrane (FM) weakening/rupture. Using it we have demonstrated that both TNF/IL-1 (modeling inflammation) and thrombin (modeling bleeding) weaken full thickness FM in a dose dependent manner concomitant with inducing biochemical changes similar to those seen in the FM physiological weak zone.
  
  
  METHODS
  As the physiological site of infection and bleeding is the choriodecidua (CD), we modified our model system with full thickness FM tissue mounted on modified Transwell culture inserts to permit directional TNF/thrombin exposure on the decidua only (rather than both sides of the FM). After incubation, medium was sampled separately from the CD facing (maternal side) or from the amnion facing (fetal side) compartments and probed for cytokine release and confirmed with western blots. The FM was strength tested within the insert.
  
  
  RESULTS
  Full-thickness FM fragments exposed to TNF or thrombin on CD side only showed dose dependent weakening and biochemical changes consistent with previous reports. Concomitantly, GM-CSF increased markedly on the CD but not the amnion side. Numerous proteases including MMP1 and MMP3 also increased on the CD side. Pre-incubation with GM-CSF antibody blocked both thrombin and TNF induced weakening. Finally, GM-CSF weakened FM in a dose dependent manner.
  
  
  CONCLUSIONS
  GM-CSF is a critical common intermediate in the thrombin and TNF FM weakening pathways.
authors.affiliation: Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA. Electronic address: dkumar@metrohealth.org.
authors.forename: D
authors.initials: D
authors.lastname: Kumar
authors.affiliation: Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Moore
authors.affiliation: Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: A
authors.initials: A
authors.lastname: Nash
authors.affiliation: Department of Reproductive Biology, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: E
authors.initials: E
authors.lastname: Springel
authors.affiliation: Department of Reproductive Biology, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: B M
authors.initials: BM
authors.lastname: Mercer
authors.affiliation: Women's Institute-Cleveland Clinic, Cleveland, OH, USA.
authors.forename: E
authors.initials: E
authors.lastname: Philipson
authors.affiliation: Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Mansour
authors.affiliation: Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA; Department of Reproductive Biology, Case Western Reserve University, Cleveland, OH, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Moore
mesh_terms: D000818:Animals; D005321:Extraembryonic Membranes / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000378:metabolism*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D011247:Pregnancy; D013917:Thrombin / Q000378:metabolism / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D014409:Tumor Necrosis Factor-alpha; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D013917:Thrombin
keywords: Biomechanics; Decidua; Fetal membranes; GM-CSF; PPROM; TNF; Thrombin; Weakening