Placental tumor necrosis factor-α protein expression during normal human gestation.

OBJECTIVE

Placental tumor necrosis factor-α (TNF-α) is a cell signaling protein. During pregnancy, TNF-α induces synthesis of matrix metalloproteinases (MMPs) which allows cytotrophoblasts to reach the spiral arteries deeper within the uterine decidua. TNF-α also augments apoptosis of vascular smooth muscle cells surrounding these arteries. In this study, chorionic villi TNF-α 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, 45.90 pg/100 mg tissue; 55.43, 40.09, 110.88 pg/100 mg tissue; and 16.63, 9.32, 31.92 pg/100 mg tissue, respectively.

CONCLUSIONS

Variations in placental TNF-α protein expression noted at different trimesters may suggest gestational age specific roles for the cytokine. The increase in TNF-α 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-α protein could contribute to gestational compromise.