Matrilysin (matrix metalloproteinase 7) in parturition, premature rupture of membranes, and intrauterine infection

OBJECTIVE: Matrix metalloproteinases are enzymes capable of degrading extra cellular matrix components. Matrilysin (matrix metalloproteinase 7), a nove l member of this family, degrades fibronectin and proteoglycans. The object ive of this study was to determine whether parturition (either term or pret erm), premature rupture of the membranes, and microbial invasion of the amn iotic cavity are associated with changes in the amniotic fluid concentratio n of matrilysin. STUDY DESIGN: A cross-sectional study was conducted with 275 women in the f ollowing categories: (1) second trimester, (2) term not in labor, (3) term in labor, (4) term with microbial invasion of the amniotic cavity, (5) pret erm labor with intact membranes without microbial invasion of the amniotic cavity who delivered at term, (6) preterm labor without microbial invasion of the amniotic cavity who delivered preterm, (7) preterm labor with microb ial invasion of the amniotic cavity, (8) preterm premature rupture of membr anes with and without microbial invasion of the amniotic cavity, and (9) te rm premature rupture of membranes not in labor and without microbial invasi on of the amniotic cavity. Matrilysin concentrations were measured with a s ensitive specific immunoassay that was validated for amniotic fluid. RESULTS: Matrilysin was detectable in 97.4% (268/275) of the samples. The c oncentration of matrilysin increased with advancing gestational age (r = 0. 8; P < .001). Parturition at term was not associated with a significant inc rease in amniotic fluid concentration of matrilysin. Preterm parturition in the absence of microbial invasion of the amniotic cavity was associated wi th a significant increase in amniotic fluid concentration of matrilysin (pr eterm labor with preterm delivery: median, 1.7 ng/mL; range, 0.45-21.6 mg/m L; vs preterm labor with term delivery: median, 1,2 ng/mL; range, 0.17-42.1 ng/mL; P < .05). Premature rupture of membranes without microbial invasion of the amniotic cavity (either term or preterm) was not associated with a significant change in the amniotic fluid matrilysin concentration. Intra-am niotic infection was associated with a significant increase in amniotic flu id matrilysin among both patients with preterm labor and patients with pret erm premature rupture of membranes (preterm labor with microbial invasion o f the amniotic cavity: median, 3.2 ng/mL; range, 0.16-21.9 ng/mL; vs preter m labor and delivery without microbial invasion of the amniotic cavity: med ian, 1.7 ng/mL; range, 0.45-21.6 ng/mL; vs preterm labor with term delivery : median, 1.2 ng/mL; range, 0.17-42.1 ng/mL; P < .01 for each comparison; a nd preterm premature rupture of membranes without microbial invasion of the amniotic cavity: median, 1.7 ng/mL; range, 0.29-13.9 ng/mL; vs preterm pre mature rupture of membranes with microbial invasion of the amniotic cavity: median, 3.6 ng/mL; range, 0.59-20.3 nl/mL; P < .01). CONCLUSION: Matrilysin is a physiologic constituent of amniotic fluid, and its concentration increases with advancing gestational age. Microbial invas ion of the amniotic cavity in preterm gestations was associated with a sign ificant increase in amniotic fluid concentration of matrilysin. Matrilysin therefore may play a role in the host defense mechanism.