Indomethacin increases abortifacient effect of PGE2 in man.

Results of this study indicate that pretreatment with indomethacin significantly increases the abortifacient effect of an intravenous infusion of PGE2 in patients admitted for abortion as a result of fetal death in utero. Indomethacin pretreatment shortened the duration of PGE2-induced abortion in primigravid and multigravid groups of patients by about 4 and 2 hours respectively. When primigravid and multigravid groups were combined, the dose of PGE2 needed for complete delivery decreases in the indomethacin-treated group by 39.9%.     

Induction of Abortion by Extra-amniotic Administration of Prostaglandins E2 and F2 α

The use of prostaglandins E₂ and F₂α, administered by extra-amniotic instillation, for the induction of abortion was studied in 94 patients in the first and second trimesters of pregnancy. Abortion was successfully induced in 87% of patients within 36 hours and in 94% within 48 hours. The mean abortion time was 22·4 hours. In 60% of patients abortion was complete.Though the differences were not statistically significant, on average multigravid patients aborted more quickly than primigravidae, while the mean abortion time in PGE₂-treated patients was less than in those receiving PGF₂α.No serious complications occurred. Some side effects were observed. Occasional vomiting was the commonest symptom but the incidence of side effects was lower than with alternative routes of administration. A leucocytosis was often noted but there were no significant instances of infection.The method has proved a safe and effective means of terminating pregnancies in the second trimester.     

Amniotomy and Oral Prostaglandin E2 Titration for Induction of Labour

The efficacy of oral prostaglandin E₂ used on a titration basis in association with amniotomy for the induction of labour was investigated in a series of 50 patients. Induction was successful in 29 out of 32 primigravid and 17 out of 18 multigravid patients. The mean induction-delivery intervals in successful cases were 10½ and 6 hours respectively. There were no significant effects on the fetuses.     

Clinical experiences with a new gel for intracervical application of prostaglandin E2 before therapeutic abortion or induction of term labor

A new gel for intracervical application of prostaglandin E₂ (PGE₂) has been elaborated and evaluated. The main component of the gel is a cross-linked starch polymer to which prostaglandins can be added and preserved for long-term storage (> 12 months).In a double blind study, 20 patients requiring legal abortion in late first trimester were given gel containing 0.25 mg PGE₂ or gel without PGE₂. The gel was applied within the cervical canal. In all patients receiving PGE₂-gel, a rapid ripening of the cervix occurred which facilitated the subsequent dilatation and evacuation. In patients receiving gel without PGE₂ cervix did not ripen. In a subsequent open study, 30 patients were treated with PGE₂-gel before therapeutic abortion. The same degree of cervical ripening was registered as for the patients receiving PGE₂-gel in the double blind study.In 50 patients at term, intracervical application of 3 ml gel containing 0.50 mg PGE₂ induced labor in 27 cases, i.e. 54 per cent of the patients. In the remaining undelivered women, a prominent cervical ripening occurred within 24 hours. No side effects of the treatment were observed.We conclude the new PGE₂-gel to be a promising future alternative in the treatment of patients with an unfavorable cervix, prior to surgical evacuation of the uterus in late first trimester abortion, as well as before induction of labor at term.     

Midtrimester abortion induced by serial intravaginal administration of prostaglandin E2 suppositories in conjunction with a contraceptive diaphragm

Midtrimester abortion was successfully induced in 68 of 69 patients with serial intravaginal administration of prostaglandin E₂ suppositories behind a contraceptive diaphragm. The mean abortion time for the successful inductions was 13.07 hours; multiparous patients aborted somewhat faster, mean 12.72 hours, as compared to nulliparous patients, mean 14.22 hours. In 36 patients the PGE₂ suppositories were placed behind an intact diaphragm and the mean abortion time was 14.89 hours. In 33 patients the PGE₂ suppositories were placed behind a diaphragm modified by having an opening incised in the center, the mean time in these patients was 11.96 hours. Of the 68 successful abortions 59% of the patients aborted in 12 hours or less and 88% aborted within 24 hours. The most frequently encountered side effect was temperature elevation of 2° F or higher which occurred in 68% of the patients. Temperatures returned to normal levels within 4 to 6 hours after the last administration of PGE₂. Gastrointestinal side effects occurred in 45% of patients, but these side effects were well tolerated and did not require termination of drug administration in any of the patients. Intravaginal administration of PGE₂ suppositories is a very effective abortifacient technique during the midtrimester, however the use of PGE₂ in conjunction with a diaphrgam did not appreciabley improve the technique although the amount of drug administered and the incidence of side effects was somewhat lower than when the PGE₂ suppositories are used alone. If a diaphragm is to be used, a modified diaphragm is indicated since it simplifies the clinical management of the abortion, eases administration of the suppositories and permits a more accurate estimation of cervical changes, vaginal bleeding and abortion.     

Selective induction of labour following administration of an oral prostaglandin E2 0.5 mg tablet hourly

Induction of labour was performed on 20 patients with favourable induction features by amniotomy and administration of a fixed dose of 0.5 mg of prostaglandin E₂ (PGE₂) hourly. Effective uterine action resulted in a mean time to delivery of 6 hrs 57 mins in primagravid patients and 4 hrs 40 mins in multigravid subjects. In two patients an intravenous oxytocin infusion was used to assist labour. There were no significant maternal or fetal side effects.     

Effect of prolonged prostaglandin exposure on prostaglandin synthesis by human lung fibroblasts

Pretreatment of human lung fibroblasts with PGE₂ but not PGF_2α enhanced synthesis of prostaglandins (PGs). The effect of the pretreatment on PG synthesis was related to the concentration of PGE₂ that was added to the culture medium. Pretreatment with PGE₂ at 5 × 10⁻¹²M did not enhance PG synthesis whereas pretreatment with PGE₂ at 5 × 10⁻⁶M induced a maximal effect. Production of PGs was increased following 1 day of pretreatment with PGE₂ and was increased further following 3 days of pretreatment. The PGE₂ treated cells showed only a slight increase in the bradykinin-induced release of radioactivity from cells prelabeled with [³H]arachidonic acid but showed a dramatic increase in the bradykinin-induced synthesis of radio-labeled PGs. The conversion of free arachidonate to PGs in both intact cells and in a cell-free preparation was increased by PGE₂ pretreatment. The presence of cyclohexamide during the pretreatment did not inhibit the PGE₂-induced activation of PG synthesis. Taken together, the results indicate that pretreatment of cells with PGE₂ increased PG synthesis by augmenting the conversion of arachidonate to PGs.     

Prostaglandin E2: Midterm abortion in rats using Silastic-PVP tubes

The results of the present study establish that 1.5 mg PGE₂ (lyophilized sodium salt) incorporated in one cm long open-ended Silastic-polyvinylpyrrolidone (PVP) tube when inserted into 10 day pregnant rats induced abortion within 70–72 hours in all the treated rats. A combined treatment of PGE₂ and 17β-estradiol failed to increase the abortion inducing effect of a Silastic-PVP-PGE₂ tube. It is observed that PGE₂ is about 4 times less potent than PGF_2α in inducing midterm abortion in rats. It is suggested that either PGE₂ exerts luteolytic effect after being converted to PGF_2α, although how it occurs is not clear; or PGE₂ causes expulsion of the fetuses by its uterine stimulating property. 17β- estradiol increases the uterine synthesis of PGF_2α as described earlier but seems not affecting the production of PGE₂ by the uterus. The release rate of ³H-PGE₂ from Silastic-PVP tube and is also described.     

Hormone changes in relation to the time of fetal death after prostaglandin-induced abortion

The changes in unconjugated estradiol-17β and estriol, progesterone and chorionic somatomammotropin (HCS) in peripheral plasma have been studied in 18 women at 30-minute intervals following intra-uterine prostaglandin E₂ administration for therapeutic termination of second trimester pregnancy. The hormonal changes were related to the time of fetal death detected by the disappearance of fetal heart pulsations. Prostaglandin E₂ was given by the intra-amniotic route with urea (5 patients) or with intravenous oxytocin (5 patients), or by the extra-amniotic route with intravenous oxytocin (8 patients). Fetal death occurred rapidly with intra-amniotic PGE₂, but usually at a late stage with extra-amniotic PGE₂. Three fetuses in the extra-amniotic group died at or just before abortion. A variety of fetal heart changes were noted and the time of fetal death did not appear to influence the time of abortion within each treatment subgroup.Estradiol and estriol showed a slight but persistent fall over 24 hours prior to induction of abortion. A more rapid fall usually occurred after induction, with a consistent fall around the time of fetal death. Progesterone and HCS usually fell much less before and immediately after fetal death. A marked rise in estradiol sometimes occurred before fetal death, particularly in the intra-amniotic PGE₂ and urea subgroup. Estriol levels declined more rapidly before than after fetal death, whereas fetal death had less consistent effects on the other hormones. All hormones had usually fallen considerably at the time of abortion, and in some individuals marked fluctuations in hormone levels were seen.     

Comparison of the actions of the 15-methyl analogs of prostaglandins E2 and F2α on hormone levels after their administration for therapeutic abortion

Plasma levels of progesterone, total estrogens and HCG were measured after the administration of 15 (S) 15-methyl prostaglandin E₂ methyl ester (15-methyl PGE₂) or 15 (S) 15-methyl prostaglandin F_2α free acid (15-methyl PGF_2α) for therapeutic abortion during the first trimester of pregnancy. 15-methyl PGE₂ given intramuscular (im) in a dose of 50μg resulted in the termination in pregnancy in four out of five patients; these subjects exhibited falls in hormone concentrations. However, an im injection of 500μg 15-methyl PGF_2α did not affect the hormone levels nor did it produce abortion in any of the five subjects studied. The results confirm that 15-methyl PGE₂ is a potent abortifacient and this action may be related to an effect that this compound has on hormone production by the corpus luteum or the feto-placental unit; 15-methyl PGF_2α does not share the same action in the dose range investigated.     

On the mechanism of action of 15-methyl-PGF2α as an abortifacient

Several hours following administration of long acting vaginal suppositories containing 3.0 mg of 15-methyl-PGF_2α for interruption of second trimester pregnancies there is an up to 10-fold increase in endogenous production of PGE₂ and PGF_2α before abortion as reflected by gas chromatographic-mass spectrometric determination of the major plasma metabolites of PGE₂ and PGF_2α. The data suggest that this increased formation of endogenous prostaglandins contributes to the induced uterine activity during the latter part of the abortion process.     

Dissociation between renal medullary PGE2-synthesis and urine PGE2-excretion. Antagonism by bumetanide of chlorazanil induced urine PGE2-excretion in rats

Normal conscious female Sprague-Dawley rats were treated with chlorazanil (3 mg/kg i.p.), and urine was collected for 3 hours. Urine prostaglandin E₂-excretion increased from 25±3 to 271±32 ng/kg/3 h. The enhancement of urine PGE₂-excretion was inhibited by pretreatment with bumetanide (75 mg/kg p.o.). In separate experiments the papillary quantity of PGE₂ was determined in freshly homogenized tissue. The basal level (14±2 ng PGE₂/papilla) was increased by chlorazanil to 51±11 ng PGE₂/papilla and 24±7 ng PGE₂/papilla at one and two hours respectively after drug administration. The capacity of chlorazanil to increase medullary PGE₂ accumulation was unaffected by bumetanide dissociated the medullary PGE₂ level from the excretion of PGE₂ in urine, when the former was elevated by chlorazanil.     

Cervical mucus concentration of prostaglandins E2 and F2α after pretreatment with mifepristone in the first trimester of pregnancy

Cervical dilatation and softening after pretreatment with mifepristone are well documented. As this effect is similar to that observed after local application of prostaglandin E₂ (PGE₂) it is tempting to speculate that the effect of mifepristone is mediated via an increase of the endogenous secretion of prostaglandins from the cervical mucosa. Eighteen healthy women in the first trimester of pregnancy were treated with oral mifepristone (200 mg) 48 and 24 hours before legal abortion by vacuum aspiration and 18 women in the same age of gestation without any pretreatment served as controls. Cervical mucus was collected for measurement of prostaglandins by radioimmunoassay before administration of the drug and in connection with vacuum aspiration. The cervical dilatation at the time of surgery was significantly increased in women given mifepristone as compared with untreated women (7.6 versus 5.8 mm). The wet weight of collected cervical mucus was significantly increased in mifepristone treated women. The amount of PGE₂ and prostaglandin F_2α per sample was unchanged in mifepristone-treated women, whereas the concentration was lower as an effect of dilution due to an increased yield in cervical secretion observed after mifepristone treatment. The present observation does not give any support to the hypothesis that mifepristone-induced cervical maturation is mediated via an increase in cervical prostaglandin production.     

Prostaglandins and thromboxanes in amniotic fluid during rivanol-induced abortion and labour

Abortion or delivery were induced by extra-amniotic instillation of Rivanol during the second trimester in twelve patients and during the third trimester in two patients with fetal death and one patient with fetal acrania. Serial sampling of amniotic fluid was performed through a transabdominal catheter and the levels of free arachidonic acid (AA), prostaglandin F₂α (PGF₂α), prostaglandin E₂ (PGE₂), 6-keto-prostaglandin F₁α (6-keto-PGF₁α) and thromboxane B₂ (TXB₂) were determined. The levels of AA, PGF₂α, PGE₂, 6-keto-PGF₁α and TXB₂ in amniotic fluid increased significantly during induction with the exception of AA in fetal death which was high and remained constant during induction. Furthermore, PGF₂α, 6-keto-PGF₁α and TXB₂ were all significantly correlated to AA.These observations suggested that free AA is released during Rivanol-induction of abortion and labour giving an increased synthesis of PGF₂α, PGE₂ prostacyclin and thromboxane A₂ in the fetal membranes and the decidua but not in the fetus. This increase might be relevant for the initiation and progress of abortion and labour in these patients.     

Clinical evaluation of endocervical prostaglandin E2-triacetin-gel for preinduction cervical softening in pregnant women at term

In an open randomized clinical trial 100 pregnant women with low Bishop Scores at term were treated either with intracervical Prostaglandin (PG) E₂ (0.5 mg in 2.5 ml triacetin-gel) 12 hours before labor induction with intravenous oxytocin or with oxytocin infusion alone. In 46 of the 50 pretreated patients (92 %) the Bishop Score progressed at least 3 points, in four cases only 2 points. The mean Bishop score in the untreated patients increased insignificantly. After PGE₂-gel administration 16 patients delivered during the 12 hour interval compared to 3 in the group without pretreatment. The first induction attempt was successful in 14 (64 %) of the 22 patients that were left to be induced after cervical softening and in 26 (57 %) of the 47 women without cervical priming. The Cesarean section rate was 10% (n=5) in the PGE₂-gel group and 12% (_n=6) in the control group. Dosage of oxytocin required for labor induction was significantly lower after cervical softening. No serious fetal or maternal side effects were observed after PGE₂ pretreatment.     

Effects of vitamin D3 on signaling by prostaglandin E2 in osteoblast-like cells

We investigated the effects of vitamin D₃ on the signaling pathways by prostaglandin E₂ (PGE₂) in osteoblast-like MC3T3-E1 cells. The pretreatment with 1,25-dihydroxyvitamin D₃ (1,25-(OH)₂D₃), an active form of vitamin D₃, significantly inhibited cAMP accumulation induced by 10 μM PGE₂ in a dose-dependent manner in the range between 1 pM and 1 nM. This effect of 1,25-(OH)₂D₃ was dependent on the time of pretreatment up to 8 h. 1,25-(OH)₂D₃ also inhibited the cAMP accumulation induced by NaF, a GTP-binding protein activator, or forskolin which directly activates adenylate cyclase. On the other hand, 1,25-(OH)₂D₃ significantly inhibited PGE₂-induced IP₃ formation in a dose-dependent manner between 10 pM and 1 nM. However, 1,25-(OH)₂D₃ had little effect on NaF-induced IP₃ formation. The pretreatment with 24,25-dihydroxyvitamin D₃, an inactive form of vitamin D₃, affected neither cAMP accumulation nor IP₃ formation induced by PGE₂. These results strongly suggest that 1,25-(OH)₂D₃ modulates the signaling by PGE₂ in osteoblast-like cells as follows: the inhibitory effect on the cAMP production is exerted at a point downstream from adenylate cyclase and the inhibitory effect on the phosphoinositide hydrolysis is exerted at the point between the PGE₂ receptor and GTP-binding protein, probably G_i2.     

Plasma Levels of Apoliporptoein A1 in Malaria-Exposed Primigravidae Are Associated with Severe Anemia

Background

Plasmodium falciparum placental malaria (PM) contributes to 10,000 maternal deaths due to severe anemia (SA) each year in Africa, primarily among primigravid women who are most susceptible. Increased levels of proinflammatory cytokines like TNF-α are associated with maternal anemia in first time mothers but not in other women. Here we aimed to identify additional changes in the plasma proteome associated with pregnancy malaria that may contribute to the development of malaria-related maternal anemia.

Principal Findings

A semi-quantitative mass spectrometry approach was used to compare the relative abundance of plasma proteins in anemic versus non-anemic women with PM. Levels of 24 proteins differed significantly between anemic and non-anemic primigravidae, including several lipid metabolism proteins and molecular transport proteins involved in the acute phase response signaling network. These differences were not observed in multigravid women who enjoy specific immunity that protect them from PM. In a confirmatory study of a larger cohort of primigravid women, levels of the lipid metabolism protein Apolipoprotein (Apo)-AI were significantly lower in PM+ women with SA.

Conclusions

Apo-AI levels are significantly lower in severely anemic primigravidae with PM, and ApoA1 levels positively correlate with hemoglobin levels in primigravid but not multigravid women. Apo-AI is known to have anti-inflammatory effects, and thus Apo-AI reductions may contribute to the inflammatory processes that result in SA.     

Effects of prostaglandin E2 on the micronucleus formation in mouse bone marrow cells by various mutagens

The effects of prostaglandin E₂ (PGE)₂, as trigger of erythroid progenitor cells into the cell cycle, were studied on the induction of micronucleu by various mutagens; with mitomicin C (MMC) the optimal protocol was established. dose-response relationship between PGE₂ doses and micronucleus frequency were observed 30 h after injection of MMC to mice administered PGE₂ 24 h previously. Sensitazion by PGE₂ pretreatment was also found for other mutagens, such as vincristine, 5-fluorouracil, benzo[a]pyrene, 1,1-dimethylhydrazine and 2-naphthylamine. These results support the hypothesis that accelerating the erythropoiesis increases the frequency of micronucleic induced by mutagens.     

Gastrotoxic activity and inhibitory effects on gastric mucosal PGE2 production with different non-steroidal anti-inflammatory drugs: Modifications induced by pretreatment with zinc acexamate

Gastrotoxic activities of different non-steroidal anti-inflammatory drugs (NSAIDs) (diclofenac, indomethacin, ketoprofen, naproxen and piroxicam) administered per os were compared with their ability to inhibit gastric prostaglandin E₂ (PGE₂) synthesis in the rat. In a parallel study, effects of pretreatment with zinc acexamate (ZAC) were also assessed. NSAIDs invariably caused gastric mucosal damage and a decrease of PGE₂ levels. A good correlation between the decrease of PGE₂ levels and the index of gastric lesion (r = 0.41; p < 0.021) was observed when results obtained with the different NSAIDs were pooled. ZAC pretreatment significantly decreased the overall severity of lesions induced by NSAIDs. However, no correlation between gastric lesion index and depletion of PGE₂ gastric levels was observed after treatment with ZAC (r = 0.012; p < 0.948). These data corroborate the hypothesis that preservation of the capability to synthesize endogenous PGs is of critical importance in the maintenance of gastric mucosal integrity. The gastroprotective action observed with ZAC involves alternative mechanisms other than modification of PGE₂ levels.     

Autocrine prostaglandin E2 signaling promotes promonocytic leukemia cell survival via COX-2 expression and MAPK pathway

The COX-2/PGE₂ pathway has been implicated in the occurrence and progression of cancer. The underlying mechanisms facilitating the production of COX-2 and its mediator, PGE₂, in cancer survival remain unknown. Herein, we investigated PGE₂-induced COX-2 expression and signaling in HL-60 cells following menadione treatment. Treatment with PGE₂ activated anti-apoptotic proteins such as Bcl-2 and Bcl-xL while reducing pro-apoptotic proteins, thereby enhancing cell survival. PGE₂ not only induced COX-2 expression, but also prevented casapse-3, PARP, and lamin B cleavage. Silencing and inhibition of COX-2 with siRNA transfection or treatment with indomethacin led to a pronounced reduction of the extracellular levels of PGE₂, and restored the menadione-induced cell death. In addition, pretreatment of cells with the MEK inhibitor PD98059 and the PKA inhibitor H89 abrogated the PGE₂-induced expression of COX-2, suggesting involvement of the MAPK and PKA pathways. These results demonstrate that PGE₂ signaling acts in an autocrine manner, and specific inhibition of PGE₂ will provide a novel approach for the treatment of leukemia. [BMB Reports 2015; 48(2): 109-114]