Induction of triggering receptors of myeloid cell (TREM-1) expression in fetal membranes and higher concentration of soluble TREM-1 in amniotic fluid with spontaneous preterm birth

Objective: To document triggering receptors of myeloid cells (TREM-1) expression in fetal membranes and to estimate soluble TREM-1 (sTREM-1) concentrations in the amniotic fluid (AF) from spontaneous preterm birth (PTB). Methods: Fetal membranes at term not in labor placed in an organ explant system were stimulated with lipopolysaccharide (LPS). Membranes were also collected from PTB with and without microbial invasion of the amniotic cavity (MIAC).TREM-1 expression and sTREM-1 concentration (in culture media and in AF from PTB) were documented using RT-PCR and ELISA, respectively. Results: LPS and preterm labor induced fetal membrane TREM-1 expression. Higher sTREM-1 concentration was documented in membranes stimulated with LPS compared with unstimulated controls. In AF,sTREM-1 concentration was higher in PTB than normal term deliveries. PTB with MIAC had higher sTREM-1 concentration compared with PTB with no MIAC. Conclusions: TREM-1 is inducible in amniochorion by LPS and preterm labor. Higher sTREM-1 in PTB and in cases with MIAC suggests a role for TREM in infection-associated PTB.