Original Article Baseline TNFaOperational Capacity in Fetal and Maternal Circulation Prior to the Onset of Labor: ‘‘Tuned for Different Purposes’’

Objective: In this study, we sought to characterize the tumor necrosis factor a (TNFa) baseline operational capacity in mature fetuses and their mothers prior to the onset of labor. Materials and Methods: We used an experimental pregnant nonhuman primate model to measure the plasma concentration of TNFa, TNF transmembrane receptor I (TNFRI), and TNFRII with validated enzyme-linked immunosorbent assays. Coefficients of correlations between the maternal and the fetal values and the soluble TNFa, TNFRI, or TNFRII concentrations and ratios were calculated. Results: The TNFa/TNFRI ratio was 3 times lower in fetal circulation than in maternal circulation. No correlations were noted between the maternal and the fetal TNFa, TNFRI, or TNFRII plasma concentrations. Conclusions: These findings suggest that the fetal and maternal baseline circulatory operational capacities of TNFa are independent of each other and tuned differently. This differential regulation of TNFa in fetal and maternal circulation at the end of pregnancy may be guided to protect the fetus from the systemic inflammatory response that is essential for the mechanisms of labor to proceed in the mother