TNF Alpha Concentrations and MRNA Expression Are Increased in Preeclamptic Placentas

Unlabelled: Tumor necrosis factor-alpha (TNF alpha), a cytokine produced mainly by macrophages, is involved in immunoregulation, the modulation of cell growth and differentiation, as well as in the induction of oxygen free radicals. In preeclamptic placentas, lipid peroxides are increased as compared to normal placentas. If TNF alpha was abnormally increased in preeclamptic placentas, it might contribute to the increased oxidative stress and the formation of lipid peroxides. We hypothesized that TNF alpha levels would be higher in preeclamptic than in normal placentas. We determined: (1) the levels of TNF alpha protein in whole placental tissue; (2) the concentrations of TNF alpha protein and lipid peroxides in the medium after 48 h of incubation of whole placental villi; (3) mRNA expression of TNF alpha. Placental TNF alpha protein levels were measured by ELISA, lipid peroxides by a spectrophotometric method specific for peroxides, and TNF alpha mRNA expression by RT-PCR.

Results: (1) TNF alpha tissue levels were significantly higher in preeclamptic than in normal placentas, P < 0.05. (2) Concentrations of both TNF alpha and lipid peroxides were higher in the incubation medium of preeclamptic than normal placentas, P < 0.05. (3) TNF alpha concentrations in the incubation medium were positively correlated with lipid peroxide concentrations, r = 0.608. (4) TNF alpha mRNA was expressed in preeclamptic placentas, but not in normal placentas.

Conclusions: TNF alpha protein concentrations and mRNA expression are higher in preeclamptic than normal placentas and this is associated with increased lipid peroxidation.