Objective: To examine the effect of magnesium sulfate (MgSO(4)) on tumor necrosis factor-alpha (TNF-alpha) secretion by preeclamptic placentas. Study design. Cotyledons of six, term, normotensive and ten, pre-eclamptic placentas were dually perfused for six hours (6h), with MgSO(4) (6-7 mg %) in the maternal reservoir [normotensive (n = 3); pre-eclamptic (n = 5)], and with control medium (without MgSO(4)) [normotensive (n = 3); pre-eclamptic (n = 5)].

Perfusate samples from the maternal and the fetal circulations were collected every 30 min throughout the 6h of perfusion, and examined for TNF- alpha levels using ELISA. Statistical significance was determined using a 2-way analysis of variance.

Results: Pre-eclamptic placentas perfused with control medium (without MgSO(4)) secreted higher levels of TNF-alpha into the fetal and the maternal circulations (1.60 +/- 0.59 pg/mL/g of cotyledon and 14.28 +/- 2.69 pg/mL/g of cotyledon, respectively), as compared to the fetal and maternal circulations of normotensive placentas (0.25 +/- 0.09 pg/mL/g of cotyledon and 6.73 +/- 1.11 pg/mL/g of cotyledon, respectively) (p < 0.01). Addition of MgSO(4) to normotensive placentas did not affect TNF-alpha levels in the fetal or maternal circulations. However, exposure of pre-eclamptic placentas to MgSO(4) significantly decreased TNF-alpha levels in both the fetal (0.89 +/- 0.09 pg/mL/g of cotyledon versus 1.6 +/- 0.59 pg/mL/g of cotyledon; p < 0.05) and the maternal circulations (4.74 +/- 2.78 pg/mL/g of cotyledon versus 14.28 +/- 2.69 pg/mL/g of cotyledon; p < 0.01).

Conclusion: Down-regulation of placental TNF-alpha secretion by MgSO(4) in pre-eclampsia might indicate a possible therapeutic effect for this agent in reducing maternal, endothelial dysfunction and in improving neonatal outcome in pre-eclampsia, by reducing TNF-alpha levels in maternal and fetal circulations.

Authors

Amash A, Weintraub AY, Sheiner E, Zeadna A, Huleihel M, Holcberg G.

The Shraga Segal Department of Microbiology and Immunology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Department of Obstetrics
and Gynecology, Soroka University Medical Center, Beer Sheva, Israel.