Placental tumor necrosis factor- protein expression during normal human gestation

Objective: Placental tumor necrosis factor- (TNF-) is a cell signaling protein. During pregnancy, TNF- induces synthesis of matrix metalloproteinases (MMPs) which allows cytotrophoblasts to reach the spiral arteries deeper within the uterine decidua. TNF- also augments apoptosis of vascular smooth muscle cells surrounding these arteries. In this study, chorionic villi TNF- protein expression throughout normal human gestation were investigated.Methods: Placental chorionic villi tissues obtained from elective surgical terminations of pregnancy and from uncomplicated term births were assayed using EIA kits (Cayman Chemicals, Ann Arbor, MI, Item # 589201).Results: The median, 25th percentile and 75th percentile values in the first (N=99), second (N=58) and third trimester (N=42) were: 36.46, 27.25, 45.90pg/100mg tissue; 55.43, 40.09, 110.88pg/100mg tissue; and 16.63, 9.32, 31.92pg/100mg tissue, respectively.Conclusions: Variations in placental TNF- protein expression noted at different trimesters may suggest gestational age specific roles for the cytokine. The increase in TNF- protein expression observed in the second trimester may be involved in upregulating synthesis of MMP and in augmenting apoptosis of vascular smooth muscle cells of the spiral arteries. A failure in this second trimester increase in TNF- protein could contribute to gestational compromise.