Hypothesis: Pentoxifylline explores new horizons in treatment of preeclampsia

Ligustrazine promotes hypoxia/reoxygenation-treated trophoblast cell proliferation and migration by regulating the microRNA-27a-3p/ATF3 axis

OBJECTIVE

Preeclampsia (PE) is a pregnancy-specific syndrome. Ligustrazine (LSZ) is involved in hypoxia/reoxygenation (H/R)-treated trophoblast cell regulation, but its mechanism remains elusive. This study explored the mechanism of LSZ in H/R-treated trophoblast cells to provide a theoretical basis for the new treatment method development for PE.

METHODS

H/R HTR8/SVneo cell model was established for PE simulation to some extent. Trophoblast cell proliferation, apoptosis rate, migration, and invasion were detected by MTT assay, flow cytometry, scratch test, and Transwell assay. miR-27a-3p expression in trophoblast cells was detected by RT-qPCR. Binding sites between miR-27a-3p and ATF3 were predicted using Starbase and verified by dual-luciferase reporter assay. Activating transcription factor 3 (ATF3), β-catenin, Cyclin D1, and c-Myc protein levels were examined using Western blot. After LSZ treatment, H/R-induced HTR8/SVneo cells were delivered with miR-27a-3p mimic or ATF3 siRNA to verify their roles in HTR8/SVneo cells.

RESULTS

LSZ facilitated the proliferation, migration, and invasion of trophoblast cells and inhibited apoptosis. miR-27a-3p was elevated in H/R-induced HTR8/SVneo cells and miR-27a-3p overexpression annulled the effect of LSZ on trophoblast cells. miR-27a-3p targeted ATF3. ATF3 silencing averted the property of LSZ on trophoblast cells. Wnt/β-catenin pathway-related proteins were repressed in H/R-induced HTR8/SVneo cells, and LSZ activated the Wnt/β-catenin pathway by promoting ATF3 expression.

CONCLUSION

LSZ mediated the Wnt pathway by regulating the miR-27a-3p/ATF3 axis, thus promoting the proliferation and migration of trophoblast cells. The protective mechanism of LSZ showed the potential application value in the treatment of PE.

Pentoxifylline as a therapeutic option for pre-eclampsia: a study on its placental effects

BACKGROUND AND PURPOSE

Recently pentoxifylline, a non-selective phosphodiesterase inhibitor and adenosine receptor antagonist, has attracted much interest for the treatment of the increased vascular resistance and endothelial dysfunction in pre-eclampsia. We therefore investigated the placental transfer, vascular effects and anti-inflammatory actions of pentoxifylline in healthy and pre-eclamptic human placentas.

EXPERIMENTAL APPROACH

The placental transfer and metabolism of pentoxifylline were studied using ex vivo placenta perfusion experiments. In wire myography experiments with chorionic plate arteries, pentoxifyllines vasodilator properties were investigated, focusing on the cGMP and cAMP pathways and adenosine receptors. Its effects on inflammatory factors were also studied in placental explants.

KEY RESULTS

Pentoxifylline transferred from the maternal to foetal circulation, reaching identical concentrations. The placenta metabolized pentoxifylline into its active metabolite lisofylline (M1), which was released into both circulations. In healthy placentas, pentoxifylline potentiated cAMP- and cGMP-induced vasodilation, as well as causing vasodilation by adenosine A₁ antagonism and via NO synthase and PKG. Pentoxifylline also reduced inflammatory factors secretion. In pre-eclamptic placentas, we observed that its vasodilator capacity was preserved, however not via NO-PKG but likely through adenosine signalling. Pentoxifylline neither potentiated vasodilation through cAMP and cGMP, nor suppressed the release of inflammatory factors from these placentas.

CONCLUSION AND IMPLICATIONS

Pentoxifylline is transferred across and metabolized by the placenta. Its beneficial effects on the NO pathway and inflammation are not retained in pre-eclampsia, limiting its application in this disease, although it could be useful for other placenta-related disorders. Future studies might focus on selective A₁ receptor antagonists as a new treatment for pre-eclampsia.

Effectiveness of pentoxifylline in severe early-onset fetal growth restriction: A randomized double-blinded clinical trial

OBJECTIVE

Management of pregnancy complicated by severe early-onset fetal growth restriction (FGR) is one of the most challenging obstetrical issues. So far, there has not been a proven option for the treatment or improvement of this condition. Improper immune response during placentation leads to inadequate trophoblast invasion and impaired utero-placental perfusion. Pentoxifylline improves the endothelial function and induces vasodilation by reducing the inflammatory-mediated cytokines. We have evaluated the effect of Pentoxifylline on fetal-placental perfusion, neonatal outcome, and the level of oxidative stress markers before and after the intervention in the setting of severe early-onset FGR.

MATERIALS AND METHODS

This study is a pilot randomized clinical trial on 40 pregnant women who had developed early-onset growth restricted fetus. Pentoxifylline and placebo were given with a dose of 400 mg per os two times daily until delivery. Serial ultrasound examination regarding fetal weight, amniotic fluid and also utero-placenta-fetal Doppler's were done. For the assessment of serum Antioxidant level, blood sampling was done once at the beginning of the study and again, at least, three weeks after the investigation. After delivery, umbilical-cord blood gas analysis, APGAR score at 1 and 5 min, NICU admission, and neonatal death were recorded and compared between the two groups.

RESULTS

Utero-placenta-fetal Doppler's in the Pentoxifylline group did not significantly change compared to the control group. Fetal weight gain was significantly higher in the Pentoxifylline group before (996.33 ± 317.41) and after (1616.89 ± 527.90) treatment (P = 0.002). Total serum antioxidant capacity significantly increased in the Pentoxifylline group (p < 0.036). Average 5 min Apgar score was significantly higher (P < 0.036) and the percentage of babies admitted to NICU was significantly lower (P < 0.030) in the treated group.

CONCLUSION

Using Pentoxifylline in pregnancy affected by FGR might show promising effects. In this study, Pentoxifylline improved the neonatal outcome, increased fetal weight gain, and reduced neonatal mortality by decreasing the level of oxidative stress markers and cutting down the inflammatory cascade.

Oxidative Stress in Placenta: Health and Diseases

During pregnancy, development of the placenta is interrelated with the oxygen concentration. Embryo development takes place in a low oxygen environment until the beginning of the second trimester when large amounts of oxygen are conveyed to meet the growth requirements. High metabolism and oxidative stress are common in the placenta. Reactive oxidative species sometimes harm placental development, but they are also reported to regulate gene transcription and downstream activities such as trophoblast proliferation, invasion, and angiogenesis. Autophagy and apoptosis are two crucial, interconnected processes in the placenta that are often influenced by oxidative stress. The proper interactions between them play an important role in placental homeostasis. However, an imbalance between the protective and destructive mechanisms of autophagy and apoptosis seems to be linked with pregnancy-related disorders such as miscarriage, preeclampsia, and intrauterine growth restriction. Thus, potential therapies to hold oxidative stress in leash, promote placentation, and avoid unwanted apoptosis are discussed.