title: Effects of antenatal betamethasone on maternal and fetoplacental matrix metalloproteinases 2 and 9 activities in human singleton pregnancies.
abstract: BACKGROUND
  A single course of antenatal betamethasone is administered to women at risk of preterm labor to advance fetal lung maturation. Matrix metalloproteinases (MMPs) are collagen-degrading enzymes that remodel extracellular matrix components during lung development. We tested the hypothesis that the effects of betamethasone on fetal lung maturation involve changes in MMP activity.
  
  
  METHODS
  We conducted a prospective, observational pilot study of three groups of singleton pregnancies. Group 1 (n = 21) was composed of women who were antenatally treated with a single course of betamethasone and who delivered < 37 weeks of gestation, group 2 (n = 7) was composed of matched untreated women who delivered < 37 weeks of gestation, and group 3 (n = 15) was composed of untreated women who delivered > 37 weeks of gestation. Maternal blood, mixed cord blood, and placental samples were collected at the time of delivery for MMP-2 and MMP-9 activity and tissue inhibitor of metalloproteinases (TIMP)-1 and -2 levels.
  
  
  RESULTS
  MMP-2 activity was significantly higher in the maternal, placental, and fetal compartments in group 1 compared with group 2 (p < .05). TIMP-2 levels were lower in groups 1 and 2 compared with group 3. Maternal TIMP-2 levels were higher (p < 0.003), whereas fetal TIMP-1 (p < .01) and MMP-9 to TIMP-1 ratios (p < .05) were lower when delivery was delayed more than 2 weeks following betamethasone treatment.
  
  
  CONCLUSIONS
  We conclude that elevated MMP-2 activity in the maternal and fetoplacental compartments may suggest a mechanism, in part, for betamethasone-induced fetal lung maturation.
authors.affiliation: Department of Pediatrics, Division of Neonatal-Perinatal Medicine, University of California, Irvine, Orange, CA 92868, USA.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Gharraee
authors.forename: Kay D A
authors.initials: KD
authors.lastname: Beharry
authors.forename: Arwin M
authors.initials: AM
authors.lastname: Valencia
authors.forename: Steve
authors.initials: S
authors.lastname: Cho
authors.forename: Leonel
authors.initials: L
authors.lastname: Guajardo
authors.forename: Michael P
authors.initials: MP
authors.lastname: Nageotte
authors.forename: Houchang D
authors.initials: HD
authors.lastname: Modanlou
mesh_terms: D000328:Adult; D001623:Betamethasone / Q000494:pharmacology*; D005260:Female; D005333:Fetus / Q000187:drug effects* / Q000201:enzymology; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D010920:Placenta / Q000187:drug effects* / Q000201:enzymology; D011247:Pregnancy / Q000378:metabolism*; D011446:Prospective Studies; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000097:blood
chemical_list: D019715:Tissue Inhibitor of Metalloproteinase-1; D001623:Betamethasone; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9