Extraovular prostaglandin F2alpha for early midtrimester abortion

Prostaglandin F2α stimulates adhesion, migration, invasion and proliferation of the human trophoblast cell line HTR-8/SVneo

INTRODUCTION

The amount of prostaglandin F_2α (PGF_2α) in the uterine lumen increases during the window of implantation in many mammals, including humans. We hypothesized that PGF_2α regulates processes related to human embryo implantation.

METHODS

The effect of PGF_2α was studied using an in vitro model of human extravillous trophoblast (EVT) cell line (HTR-8/SVneo). Adhesion, proliferation, invasion and migration assays, zymography for metalloproteinases (MMP) activity, and gene/protein expression analyses were applied. Doses of 100 nM and/or 1 μM of PGF_2α and fluprostenol were used. PGF_2α receptor (PTGFR), MMP9 and MMP2 proteins in the human first trimester placenta were localized by immunohistochemistry and immunofluorescence.

RESULTS

This study is the first reporting the expression of PTGFR protein in the first trimester placenta, as well as in HTR-8/SVneo cells. PGF_2α and fluprostenol increased HTR-8/SVneo cell proliferation and adhesion to extracellular matrix protein (P < 0.05). This effect was abolished by mitogen activated protein kinases (MAPK) inhibitor. PGF_2α induced phosphorylation of focal adhesion kinase and MAPK1/3 (P < 0.05). PGF_2α increased mRNA content and protein activity of MMP9, and gene and protein expression of interleukin-6 (P < 0.05). EVT cell migration and invasiveness were stimulated by PGF_2α (P < 0.05). The PGF_2α effect on cell invasion was reduced by inhibitors of MMP2, MMP9 and mTOR. In all experiments, the stimulatory effects of PGF_2α were diminished by using a PTGFR antagonist.

DISCUSSION

Our findings suggest a significant role for PGF_2α in mechanisms associated with implantation. PGF_2α acting by PTGFR in HTR-8/SVneo cells stimulates their adhesion and proliferation through the MAPK signaling pathway and increases invasiveness inducing MMP proteolytic activity and mTOR signaling.

Multiple dose extraamniotic prostaglandin gel for second trimester termination of pregnancy

Multiple doses of PGF2 alpha gel were administered into the extraamniotic space in 30 patients to induce mid-trimester termination of pregnancy. In 18 of these patients, repeat doses of gel were given only in the absence of uterine contractions and in 12 patients the gel was administered every 4 hours, irrespective of uterine activity. The mean time to abortion in all patients was 13.9 hours; no benefit seemed to accrue from using routine 4-hourly doses and it is recommended that repeat doses are given only when contractions are absent. The latter technique compares favourably with the use of other natural prostaglandins and prostaglandin analogues.

Induction of midtrimester abortion by the combined method of continuous extravovular infusion of prostaglandin F2alpha and intracervical laminaria tents

Midtrimester abortion was successfully induced in 55 of 60 patients with continuous extraovular infusion of prostaglandin F2alpha (PGF2alpha) following the insertion of intracervical laminaria tents. Intravenous oxytocin was also used in 38 (63%) of the 60 patients. The mean induction-abortion time (IAT) was 11.72 hours +/- 1.06 SD). Abortion was completed in 40% within 8 hours, 80% within 16 hours, and 93% within 24 hours. The mean total dose of PGF2alpha was 41.9 mg. There was no significant difference in IAT between the parous patients (13.40 hours +/- 1.90 SD) and the nulliparous patients (10.41 hours +/- 1.13 SD). There was no apparent correlation between IAT and the stages of gestation (12 to 22 weeks). The five patients who failed to abort within 24 to 36 hours underwent uterine evacuation, which was easily accomplished because there was a marked degree of cervical dilatation. Side effects and complications of the technique were few. Endometritis occurred in three patients, two of whom had had intrauterine devices in situ until just prior to the procedure. It appears that this method has a high success rate, an acceptable safety factor, good patient tolerance, and relatively few side effects.