title: The inflammatory milieu of amniotic fluid in acute-chorioamnionitis decreases with increasing gestational age.
abstract: BACKGROUND
  The inflammatory milieu decreases in the placenta and amniotic fluid (AF) with gestational age (GA). However, there is no information about whether the inflammatory milieu of AF in the setting of the same placental inflammatory condition decreases with GA. We hypothesized that the inflammatory milieu of AF in acute chorioamnionitis would decrease with increasing GA.
  
  
  METHODS
  The inflammatory milieu of AF was examined in 617 singleton preterm pregnancies (<36 weeks) delivered within 5 days of amniocentesis. Study population was divided into GA at delivery ≤30 weeks (n = 148), 30-34 weeks (n = 226), and 34-36 weeks (n = 226). Acute-chorioamnionitis was classified according to the severity (i.e., mild, total grade 1; moderate, total grade 2; and severe, total grade 3-6) or involved compartment (i.e., chorionic plate, amnion and chorio-decidua). The inflammatory milieu of AF was determined by matrix metalloproteinase-8 (MMP-8) concentration.
  
  
  RESULTS
  1) AF MMP-8 concentrations decreased in patients with acute-chorioamnionitis (P < 0.001), but not inflammation-free placenta, with increasing GA; 2) AF MMP-8 concentrations were less intense at higher GA in patients with moderate and severe (each-for P < 0.005), but not mild, acute-chorioamnionitis; 3) AF MMP-8 concentrations decreased in the context of the same involved compartment (i.e., chorionic plate inflammation, amnionitis, or chorio-deciduitis) of acute-chorioamnionitis (each-for P < 0.001) with increasing GA; 4) Moreover, there was a significant inverse relationship between GA and AF MMP-8 concentrations in patients with acute-chorioamnionitis (r = -0.453, P < 0.0000001), but not inflammation-free placenta (r = -0.071, P = 0.170).
  
  
  CONCLUSIONS
  AF MMP-8 concentrations in acute-chorioamnionitis distinctly decrease throughout preterm-gestation. This finding suggests that the inflammatory milieu of AF decrease in acute-chorioamnionitis with GA.
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, South Korea.
authors.forename: Chan-Wook
authors.initials: CW
authors.lastname: Park
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, South Korea. Electronic address: jsparkmd@snu.ac.kr.
authors.forename: Joong Shin
authors.initials: JS
authors.lastname: Park
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, South Korea.
authors.forename: Jong Kwan
authors.initials: JK
authors.lastname: Jun
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, South Korea.
authors.forename: Bo Hyun
authors.initials: BH
authors.lastname: Yoon
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000378:metabolism*; D002821:Chorioamnionitis / Q000378:metabolism*; D005260:Female; D005865:Gestational Age; D006801:Humans; D020784:Matrix Metalloproteinase 8 / Q000378:metabolism*; D011247:Pregnancy
chemical_list: C488762:MMP8 protein, human; D020784:Matrix Metalloproteinase 8
keywords: Amniotic fluid; Chorioamnionitis; Gestational age; Inflammatory milieu; Placenta; Preterm gestation