Differences in the placental membrane cytokine response: A possible explanation for the racial disparity in preterm birth

Problem The prematurity rate is higher in African-Americans (AA) compared with Caucasians (C). As spontaneous preterm labor has been hypothesized to be a host inflammatory response disease racial differences in human placental membrane inflammatory cytokine and prostaglandin pathway gene expression patterns between AA and C were examined in this report. Method of study Placental membranes (amniochorion) collected from AA and C women from cesareans at term were maintained in an organ explant system and stimulated with endotoxin (lipopolysaccharide, LPS). Microarray analysis and enzyme-linked immunosorbent assay was performed on mRNAs and culture media from AA- and C-derived membranes to document any differences in mRNA expression and protein production of IL-1, IL-6, IL-8, IL-10 and expression of cyclooxygenase 1 (COX-1), COX-2 and 15-hydroxyprostaglandin dehydrogenase (PGDH). Results Increased mRNA expression of IL-1, IL-8 and COX-2 in AA and IL-6, IL-10, COX-1 and PGDH in C were documented after LPS stimulation. Concentration of IL-1 was significantly higher in media derived from AA whereas IL-6 and IL-10 concentrations were higher in C with no differences observed in IL-8 after LPS stimulation compared with respective unstimulated controls. Conclusion These data document ethnic diversity in placental membrane immune response.