title: Initial characterization of the microenvironment that regulates connective tissue degradation in amniochorion during normal human labor.
abstract: Extracellular matrix degradation in fetal membranes leading to its rupture is coupled to myometrial activity and cervical ripening during human normal labor. Mechanisms which modulate collagen degradation in amniochorion during labor have not been elucidated. Initial characterization of the effect of different blood compartments on connective tissue degradation in amniochorion during human labor was explored. Amniochorion explants were stimulated with plasma of maternal venous blood, umbilical cord blood or placental blood, obtained from women with pregnancies at term, with or without labor. MMP-2 and MMP-9 activities were quantified in conditioned media by gelatin-zymography as an index of connective tissue degradation. Collagen content was measured in tissue explants and collagen fibrils distribution was examined by electron microscopy. Placental plasma from term pregnancies, with or without labor, is enriched with soluble signals that enhance the in vitro MMP-9 production by amniochorion. Accompanying ultrastructural distortion of collagen fibers and demonstration of collagen degradation fragments confirmed induction of extracellular matrix degradation. Control experiments in which MMP-9 activity was blocked with TIMP-1 resulted in inhibition of all the above mentioned changes. These results suggest that placental intervillous space is a functional compartment in which mediators capable to induce collagen degradation in amniochorion are selectively expressed during human labor.
authors.affiliation: Research Direction, Instituto Nacional de Perinatologia, Mexico City, Mexico.
authors.forename: Guadalupe
authors.initials: G
authors.lastname: Estrada-Gutierrez
authors.forename: Veronica
authors.initials: V
authors.lastname: Zaga
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Gonzalez-Jimenez
authors.forename: Jorge
authors.initials: J
authors.lastname: Beltran-Montoya
authors.forename: Rolando
authors.initials: R
authors.lastname: Maida-Claros
authors.forename: Silvia
authors.initials: S
authors.lastname: Giono-Cerezo
authors.forename: Felipe
authors.initials: F
authors.lastname: Vadillo-Ortega
mesh_terms: D000650:Amnion / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D002823:Chorion / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D003238:Connective Tissue / Q000201:enzymology / Q000378:metabolism*; D005260:Female; D006801:Humans; D007743:Labor, Obstetric / Q000378:metabolism*; D007958:Leukocyte Count; D020778:Matrix Metalloproteinase 2 / Q000235:genetics / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D011247:Pregnancy; D046509:Tissue Culture Techniques
chemical_list: D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9