Screening of novel matrix metalloproteinases (MMPs) in human fetal membranes

Objective: Endogenous activation of matrix metalloproteinase (MMP) in human fetal membranes is hypothesized to contribute to membrane weakening leading to early rupture and is also involved in the initiation of labor. Our laboratory and several others have studied the source and action of some of these MMPs. The objective of this study is to document the expression pattern of most of the MMPs cloned and sequenced so far in amniochorion during preterm premature rupture of membranes (pPROM), at term not in labor and during term labor. Materials and Methods: Placentas were collected from women with PROM, term not in labor after C-sections and from women after term vaginal delivery. Membranes were separated from the placenta and a section away from the rupture site was selected. Amniochorion were separated from the placenta. RT-PCR was performed to study the expression pattern of MMP15 (MT2-MMP), MMP16 (MT3-MMP), MMP17 (MT4-MMP), MMP18, MMP20, MMP23, MMP24 (MT5-MMP), MMP25 (MT6-MMP), and MMP 26 using specific primers. Results: A differential pattern of expression was noted for some of the novel MMPs screened in this study in human fetal membranes. mRNA for most of the MMPs were expressed by amniochorion. MMP16 [membrane type metalloproteinase 3], MMP20 [enamelysin], and MMP26 [matrilysin] were not expressed. Conclusion: Amniochorion expresses several of the MMP genes at the time of pPROM, term not in labor and during active labor. We have previously reported the expression pattern of other MMPs and their inhibitors and their potential role in PROM. These findings support our hypothesis that amniochorion has a fully functional MMP system.