Preterm labor and bacterial intraamniotic infection: arachidonic acid liberation by phospholipase A2 of Fusobacterium nucleatum.

Abstract

The studies presented in this report were undertaken to evaluate whether Fusobacterium nucleatum, a common anaerobic isolate in intrauterine infection, stimulates arachidonic acid metabolism, a rate-limiting step for prostaglandin synthesis, in the human uterine endometrium. Effects of F nucleatum on arachidonic acid liberation from human uterine endometrial cells and of F nucleatum extract on lysophosphatidylcholine production in human uterine endometrial cells were investigated. When human uterine endometrial cells labeled with tritiated arachidonic acid to an isotopically steady state were exposed to an extract of F nucleatum, arachidonic acid liberation was stimulated, accompanied by lysophospholipid formation. Similar stimulatory effects on phospholipid degradation were also observed in the experiment with bacterially conditioned media. These results suggest that F nucleatum stimulates endometrial phospholipid metabolism, related to activity of phospholipase A2, which might induce the onset of labor associated with intraamniotic infection.