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Aspirin inhibits both lipid peroxides and thromboxane in preeclamptic placentas
1Department of Obstetrics and Gynecology, Medical College of Virginia, Virginia Commonwealth University, Richmond, USA.
Insights
Low-dose aspirin selectively inhibits lipid peroxides and thromboxane in preeclamptic placentas, without affecting prostacyclin. This dose-dependent effect may explain aspirin
Area of Science:
- Obstetrics and Gynecology
- Pharmacology
- Biochemistry
Background:
- Preeclampsia is a pregnancy complication causing hypertension, fetal growth issues, and imbalances in thromboxane, prostacyclin, and lipid peroxides.
- Low-dose aspirin (ASA) is being studied for preeclampsia prevention due to its known inhibition of thromboxane synthesis.
Purpose of the Study:
- To investigate the effects of aspirin on lipid peroxide, thromboxane, and prostacyclin production in preeclamptic placental tissues.
- To determine if aspirin's potential benefits extend to inhibiting lipid peroxide synthesis.
Main Methods:
- Human placental tissues from preeclamptic women were incubated with varying aspirin concentrations.
- Samples were analyzed over 48 hours for thromboxane B2, 6-keto-PGF1 alpha, and lipid peroxides.
Main Results:
- Aspirin at 5 x 10(-5) M significantly inhibited both lipid peroxides and thromboxane production (p < 0.05).
- Prostacyclin production was not significantly affected at this dose (p > 0.05).
- Lower aspirin doses showed no effect, while higher doses inhibited all three compounds.
Conclusions:
- Aspirin demonstrates a dose-dependent inhibition of lipid peroxides, thromboxane, and prostacyclin in preeclamptic placentas.
- Low-dose aspirin (5 x 10(-5) M) selectively inhibits lipid peroxides and thromboxane, sparing prostacyclin.
- This selective inhibition may underlie the therapeutic efficacy of low-dose aspirin in preeclampsia prevention.
Abstract:
Preeclampsia is a hypertensive disorder of human pregnancy that is a leading cause of premature delivery and fetal growth retardation. It is characterized by hypertension, reduced uteroplacental blood flow, proteinuria, and edema. Preeclampsia is associated with an imbalance of increased thromboxane and decreased prostacyclin, as well as with an imbalance of increased lipid peroxides and decreased antioxidants. Low-dose aspirin (ASA) therapy (60-150 mg/day) is being evaluated for the prevention of preeclampsia. The rationale for this is that low-dose ASA selectively inhibits thromboxane synthesis without affecting prostacyclin synthesis. We hypothesized that ASA might also inhibit the synthesis of lipid peroxides. The purpose of this study was to examine the effects of aspirin on lipid peroxide, thromboxane, and prostacyclin production rates in placentas obtained from women with preeclampsia. Placentas were obtained from five preeclamptic women. Placental tissues (350 mg) were incubated in Dulbecco's Modified Eagles Medium (DMEM) for 48 h, alone and with varying concentrations of aspirin: 1 x 10(-6) M, 1 x 10(-5) M, 5 x 10(-5) M, 1 x 10(-4) M, and 5 x 10(-4) M. Samples were collected at 0, 2, 6, 16, 28, and 48 h of incubation, and analyzed for thromboxane and prostacyclin by RIA of their stable metabolites, thromboxane B2 and 6-keto-PGF1 alpha, and for lipid peroxides by peroxide equivalents. As compared to control, an aspirin concentration of 5 x 10(-5) M significantly inhibited (p < 0.05) both lipid peroxides (3.15 +/- 0.49 vs. 1.90 +/- 0.31 pmol/microgram/h) and thromboxane (0.66 +/- 0.11 vs. 0.32 +/- 0.10 pg/microgram/h), but not prostacyclin (0.24 +/- 0.05 vs. 0.17 +/- 0.02 pg/microgram/h, p > 0.05). Lower aspirin doses (1 x 10(-6) M, 1 x 10(-5) M) had no effect, whereas higher doses (1 x 10(-4) M and 5 x 10(-4) M) inhibited all three compounds. We conclude that aspirin inhibits lipid peroxides, as well as thromboxane and prostacyclin, in preeclamptic placentas. The inhibitory effects are dose dependent. Low-dose aspirin (5 x 10(-5) M) selectively inhibits lipid peroxides and thromboxane without affecting prostacyclin. We speculate that the selective inhibitory effect of low-dose aspirin may account for its effectiveness in the prevention of preeclampsia.