Large-scale downregulation of cytokeratins in amniotic epithelium after Group B Streptococcus choriodecidual infection in Macaca nemestrina: a pathway to PPROM

Early events leading to intrauterine infection remain poorly defined, but may hold the key to a therapeutic intervention for preterm delivery. To determine early molecular pathways associated with membrane weakening that may progress to preterm premature rupture of membranes (PPROM), we examined the effects of Group B Streptococcus (GBS) on fetal membranes after a choriodecidual infection. Ten chronically catheterized pregnant monkeys (Macaca nemestrina) at 118-125 days gestation (term=172 days) received choriodecidual inoculation of either: 1) Group B Streptococcus (n=5) or 2) saline (n=5). Cesarean section and fetal necropsy was performed in the first week after GBS or saline inoculation regardless of labor. Macaca nemestrina chorioamnion samples were obtained at the site of inocculation immediately after cesarean delivery 4 days after GBS inoculation and 7 days after saline inoculation. RNA was extracted and profiled by microarray. Results were analyzed using single gene, Gene Set, and Ingenuity Pathway Analysis. Validation was by RT-PCR and immunohistochemistry.