title: Matrix metalloproteinase 3 in parturition, premature rupture of the membranes, and microbial invasion of the amniotic cavity.
abstract: OBJECTIVE
  Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that are expressed in many inflammatory conditions and contribute to connective tissue breakdown. Stromelysin 1 [matrix metalloproteinase 3 (MMP-3)], a novel member of this family, is produced in the context of infection and is able to activate the latent forms of other MMPs. The purpose of this study was to determine if parturition (either term or preterm), premature rupture of the membranes (PROM), and microbial invasion of the amniotic cavity are associated with changes in amniotic fluid concentrations of MMP-3.
  
  
  METHODS
  A cross-sectional study was conducted, which included women who underwent transabdominal amniocentesis (n = 365) in the following categories: (1) mid-trimester with a subsequent normal pregnancy outcome (n = 84) and a subsequent fetal loss (n = 10); (2) preterm labor with intact membranes without microbial invasion of the amniotic cavity who delivered at term (n = 36), or prematurely (n = 50), and preterm labor with microbial invasion of the amniotic cavity (n = 25); (3) preterm PROM with (n = 25) and without (n = 26) microbial invasion of the amniotic cavity; (4) term with intact membranes in the absence of microbial invasion of the amniotic cavity, in labor (n = 52) and not in labor (n = 31); and (5) term with PROM in the absence of microbial invasion of the amniotic cavity and not in labor (n = 26). MMP-3 concentrations in amniotic fluid were measured by a sensitive and specific immunoassay that was validated for amniotic fluid. MMP-3 concentrations were normalized using logarithmic transformation for statistical analysis. Parametric statistics were used and a p value < 0.05 was considered statistically significant.
  
  
  RESULTS
  (1) MMP-3 was detected in 99.5% (363/365) of amniotic fluid samples, and its concentration did not change with advancing gestational age. (2) Spontaneous parturition at term and preterm was associated with a significant increase in amniotic fluid MMP-3 concentrations (p = 0.04 and p = 0.002, respectively). (3) Spontaneous rupture of membranes in term and preterm gestations was not associated with significant changes in amniotic fluid MMP-3 concentrations. (4) Intra-amniotic infection was associated with a significant increase in amniotic fluid MMP-3 concentrations in both women with preterm labor and intact membranes (p = 0.03), and women with preterm PROM (p = 0.02). (5) Subsequent fetal loss after genetic amniocentesis was not associated with significant changes in mid-trimester concentrations of amniotic fluid MMP-3.
  
  
  CONCLUSIONS
  (1) MMP-3 is a physiologic constituent of amniotic fluid. (2) MMP-3 may play a role in the mechanisms of human parturition and in the regulation of the host response to intrauterine infection.
authors.affiliation: Perinatology Research Branch, National Institute of Child Health and Human Development, NIH/DHHS, Bethesda, Maryland, USA.
authors.forename: Kyo Hoon
authors.initials: KH
authors.lastname: Park
authors.forename: Tinnakorn
authors.initials: T
authors.lastname: Chaiworapongsa
authors.forename: Yeon Mee
authors.initials: YM
authors.lastname: Kim
authors.forename: Jimmy
authors.initials: J
authors.lastname: Espinoza
authors.forename: Jun
authors.initials: J
authors.lastname: Yoshimatsu
authors.forename: Sam
authors.initials: S
authors.lastname: Edwin
authors.forename: Ricardo
authors.initials: R
authors.lastname: Gomez
authors.forename: Bo Hyun
authors.initials: BH
authors.lastname: Yoon
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
mesh_terms: D000650:Amnion / Q000382:microbiology*; D000653:Amniotic Fluid / Q000737:chemistry* / Q000382:microbiology*; D003430:Cross-Sectional Studies; D005260:Female; D005322:Premature Rupture of Fetal Membranes / Q000201:enzymology* / Q000382:microbiology*; D005865:Gestational Age; D006801:Humans; D008423:Maternal Age; D019278:Matrix Metalloproteinase 3 / Q000032:analysis*; D007752:Obstetric Labor, Premature / Q000201:enzymology; D010298:Parity; D036801:Parturition / Q000502:physiology; D011247:Pregnancy; D012016:Reference Values; D012189:Retrospective Studies
chemical_list: D019278:Matrix Metalloproteinase 3