Sildenafil citrate decreased natural killer cell activity and enhanced chance of successful pregnancy in women with a history of recurrent miscarriage

Effects of sildenafil treatment on placental immune cell subsets in early-onset fetal growth restriction

INTRODUCTION

Early onset fetal growth restriction is a common pregnancy complication with significant risk of perinatal mortality and morbidity. The most common etiology is placental insufficiency, reflected by several placental lesions that appear with fetal growth restriction. Placental immune cells are involved in almost all aspects of the development of the placenta and immune cell imbalances have been related to common pregnancy complications. The STRIDER trial investigated the therapeutic potential of sildenafil. No clinical improvements were observed, however, since sildenafil can have immunological effects, we aimed to investigate if sildenafil alters local placental immune cells.

METHODS

Placental samples from 146 patients were included from the STRIDER trial and stained with IHC for leukocytes (CD45), macrophages (CD68 and CD206), T cells (CD3 and CD8), regulatory T cells (FOXP3) and NK cells (CD56). Immune cells were quantified in the decidua basalis and villi at term using a trained detection classifier. In addition, maternal plasma cytokines were measured at inclusion.

RESULTS

In the sildenafil group, numbers of CD3+ T cells, CD68+ and CD206+ macrophages and CD56+ NK cell were greater in the decidua basalis compared to the control group. Correlating maternal plasma cytokines to placental immune cell subsets showed predominantly negative correlations in the placebo group, whereas most cytokines correlated positively to placental immune cells in the sildenafil group.

DISCUSSION

Our data demonstrates the immunomodulatory effects of sildenafil in pregnancies complicated by early onset fetal growth restriction and offers valuable insights on the use of immunomodulatory drugs in pregnancy.

Placental histopathology in early-onset fetal growth restriction with use of sildenafil, a secondary analysis of the Dutch STRIDER study

OBJECTIVES

Placental pathology lesions are common in early-onset fetal growth restriction (eoFGR). Therapeutic interventions to improve eoFGR outcomes are needed. In the international STRIDER trials (Sildenafil Therapy In Dismal prognosis Early-onset intrauterine growth Restriction) sildenafil didn't improve perinatal outcomes of eoFGR. We aimed to study the underlying placental pathology in the Dutch STRIDER trial and the effects of sildenafil on placental histopathology by describing the associations with sildenafil treatment, placental-dysfunction serum biomarkers and markers of oxidative stress.

METHODS

The Dutch STRIDER trial was a randomized controlled trial of sildenafil versus placebo in 216 singleton pregnancies complicated by eoFGR, included between 20+0- and 29+6-weeks' gestation. In 158 cases, placental histology was available. Lesions were classified independently by three perinatal pathologists blinded for clinical data, according to the international criteria of the Amsterdam Placental Workshop Group Consensus Statement. Blood samples taken at inclusion were analyzed for free thiols (FT), placental growth factor (PlGF) and soluble FMS-like tyrosine kinase-1 (sFlt-1, n = 85).

RESULTS

The 'big four' placental lesions (maternal and fetal vascular malperfusion, and chronic or acute inflammatory lesions) were equally distributed in both groups. However, massive perivillous fibrin deposition (MPFD) and chronic histiocytic intervillositis (CHIV) were less common in the sildenafil-treated group compared to the placebo-treated group (p = 0.026 and p = 0.043). FT, PlGF and sFlt-1 at inclusion were not discriminative for placental lesions.

CONCLUSIONS

Sildenafil had no effect on common placental lesions. The lower incidence of MPFD and CHIV after sildenafil exposure merits more research on the interaction between sildenafil and the immune system.

Comparative effectiveness of sildenafil citrate and estradiol valerate as adjuvants during clomiphene citrate-assisted ovarian stimulation cycles in patients with unexplained infertility: a double-blind randomized controlled trial

OBJECTIVE

This study aimed to assess the effect of sildenafil citrate and estradiol valerate as adjuvant therapy during ovarian stimulation cycles with clomiphene citrate in patients with unexplained infertility in Kisangani.

METHOD

A double-blind, randomized controlled trial was conducted for two years at two specialized health facilities in Kisangani (University Clinics of Kisangani and "Clinique des Anges Kisangani"). The population included 148 patients, 74 of whom were on clomiphene citrate + sildenafil citrate (CCSC) regimens and 74 of whom were on clomiphene citrate + estradiol valerate (CCEV) regimens for three months. The primary indicator was the conception rate, with secondary outcomes encompassing endometrial thickness, appearance and vascularity, the number of mature follicles and ovulation rate.

RESULTS

The two groups were comparable in terms of sociodemographic and clinical characteristics. The mean duration of attempting to conceive was 4.39 years versus 4.36 years (P = 0.839), while the mean AFC was 11.51 versus 11.46 (P = 0.831), in the CCSC group versus CCEV group respectively. Secondary infertility was the most frequent diagnosis in each of the two groups. The biochemical pregnancy rate was comparable between the two groups (P = 0.385), while the clinical pregnancy rate was significantly higher in the CCSC group versus CCEV group (P = 0.04). Both perifollicular flow and the ovulation rate were significantly higher in the CCSC group versus the CCEV group (P = 0.006 and P = 0.002 respectively). However, endometrial vascularity/thickness, and the number of Graafian follicles were not significantly different between the two groups.

CONCLUSION

As an adjuvant, sildenafil increases the rate of clinical pregnancy more than does estradiol in patients with unexplained infertility undergoing ovarian stimulation with clomiphene citrate.

STUDY REGISTRATION

PACTR 202,310,849,449,401 (Pan African Clinical Trials Registry).

Rethinking of phosphodiesterase 5 inhibition: the old, the new and the perspective in human health

The phosphodiesterases type 5 (PDE5) are catalytic enzymes converting the second messenger cyclic guanosine monophosphate (cGMP) to 5' GMP. While intracellular cGMP reduction is associated with several detrimental effects, cGMP stabilization associates with numerous benefits. The PDE5 specific inhibitors, PDE5i, found their explosive fortune as first-line treatment for erectile dysfunction (ED), due to their powerful vasoactive properties. The favorable effect for ED emerged as side-effect when PDE5i were originally proposed for coronary artery disease (CAD). From that point on, the use of PDE5i captured the attention of researchers, clinicians, and companies. Indeed, PDE5-induced intracellular cGMP stabilization offers a range of therapeutic opportunities associated not only with vasoactive effects, but also with immune regulatory/anti-inflammatory actions. Chronic inflammation is acknowledged as the common link underlying most non-communicable diseases, including metabolic and cardiac diseases, autoimmune and neurodegenerative disorders, cancer. In this scenario, the clinical exploitation of PDE5i is undeniably beyond ED, representing a potential therapeutic tool in several human diseases. This review aims to overview the biological actions exerted by PDE5i, focusing on their ability as modulators of inflammation-related human diseases, with particular attention to inflammatory-related disorders, like cardiac diseases and cancer.

Peripheral blood natural killer cell cytotoxicity in recurrent miscarriage: a systematic review and meta-analysis

Dysregulated natural killer (NK) cells have been associated with recurrent miscarriages (RM). Studies have suggested that high peripheral blood NK cell cytotoxicities (pNKCs) are associated with an increased risk of RM. The aim of this systematic review (SR) and meta-analysis (MAs) is to investigate the difference in pNKC between nonpregnant and pregnant women with RM and controls and determine whether pNKC is reduced by immunotherapy. We searched the PubMed/Medline, Embase, and Web of Science databases. The MAs were conducted to compare pNKCs between women with and without RM before and during pregnancy as well as pre- and post-immunotherapy. Risk of bias in nonrandomized studies was assessed by the Newcastle-Ottawa Scale. Statistical analysis was performed using the Review Manager software. A total of 19 studies were included in the SR and 14 studies in the MAs. The MAs revealed higher pNKCs among nonpregnant women with RM compared to controls (MD, 7.99 95 %CI 6.40-9.58; p < 0.00001). pNKCs were also higher in pregnant women with RM than in pregnant controls (MD, 8.21 95 %CI 6.08-10.34; p < 0.00001). Women with RM showed significantly decreased pNKCs after the immunotherapy compared to before (MD, -8.20 95 %CI -10.20 - -6.19; p < 0, 00001). Additionally, there is an association between high pNKCs and the risk of pregnancy loss in women with RM. However, included studies showed substantial heterogeneities regarding the inclusion criteria of patients, techniques measuring pNKC, and types of immunotherapies. More studies are needed to evaluate the clinical efficiency of pNKCs in managing RM.

Comparative Evaluation of Sildenafil Citrate and Estrogen as an Adjuvant Therapy for Treatment of Unexplained Infertility in Women

BACKGROUND

Uterine blood flow determines endometrial thickness. This study examined how vaginal sildenafil citrate and estradiol valerate altered endometrial thickness, blood flow, and fertility in infertile women.

METHODS

This study observed 148 infertile women whose infertility was unexplained. Group 1 comprised 48 patients who received oral estradiol valerate (Cyclo-Progynova 2 mg/12 h white tablets) from day 6 till ovulation was initiated with clomiphene citrate. A number of 50 participants in group 2 received oral sildenafil (Respatio 20 mg/12 h film-coated tablets) for 5 days starting the day after their previous menstrual period and finishing on the day they ovulated with clomiphene citrate. Group 3 was the control group, with 50 patients receiving clomiphene citrate (Technovula 50 mg/12 h tablets) ovulation induction from the 2nd to 7th day of cycle. All patients had transvaginal ultrasounds to determine ovulation, follicle count, and fertility. Miscarriage, ectopic pregnancy, and multiple pregnancies were monitored for three months.

RESULTS

The three groups' mean ETs differed statistically at p = 0.0004. A statistically significant difference was found between the three groups in terms of the number of follicles, with 69% of patients in group 1 having one and 31% having two or more, 76% of patients in group 2 having one and 24% having two or more, and 90% of patients in the control group having one and 10% having two or more (p = 0.038). The clinical pregnancy rates of the three groups were 58%, 46%, and 27%, respectively (p = 0.005). The distribution of all side effects was not statistically different between the three groups.

CONCLUSION

It is possible to claim that adding oral estrogen to clomiphene citrate therapy as an adjuvant therapy can improve endometrial thickness and, as a result, increase the pregnancy rates in unexplained infertility compared to sildenafil, especially in cases where the infertility has lasted less than two years. Most people who take sildenafil end up with a mild headache.

Use of phosphodiesterase-5 inhibitors and the incidence of melanoma

INTRODUCTION

Recent evidence of a causal link between Phosphodiesterase-5-inhibitor (PDE-5i) use and melanoma has caused concern in PDE-5i use and was even addressed in the 2018 American Urological Association guideline on erectile dysfunction (ED). Given that several studies have affirmed this low probability but statistically significant association, one might expect a shift in melanoma diagnoses since PDE-5is were introduced in 1998. We sought to determine if the introduction of PDE-5i drugs for ED treatment increased incidence of melanoma.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to compare the incidence of melanoma diagnosis in American men between 1973 and 2015, providing over a decade of data before and after PDE-5i introduction in 1998. Interrupted time-series and logistic regression were used to assess this relationship.

RESULTS

Over 43 years, the SEER database has reported 292,166 cases of Melanoma, with males accounting for 53.7% of cases (Standard deviation [SD] 3%, Range 47.5-58.3%). After the introduction of PDE-5i, there was no proportional increase in melanoma diagnoses, in fact demonstrating a 2% lower incidence from prediction models (p < 0.05).

CONCLUSION

Our analysis of the SEER database demonstrates that the trend in incidence of melanoma has fallen in the era of PDE-5i use for ED. These findings may be of value in counseling patients anxious about the potential association between PDE-5i use and skin cancer; however, continued research analyzing individual-level risk are needed.

Molecular Clues to Understanding Causes of Human-Assisted Reproduction Treatment Failures and Possible Treatment Options

More than forty years after the first birth following in vitro fertilization (IVF), the success rates of IVF and of IVF-derived assisted reproduction techniques (ART) still remain relatively low. Interindividual differences between infertile couples and the nature of the problems underlying their infertility appear to be underestimated nowadays. Consequently, the molecular basis of each couple's reproductive function and of its disturbances is needed to offer an individualized diagnostic and therapeutic approaches to each couple, instead of applying a standard or minimally adapted protocols to everybody. Interindividual differences include sperm and oocyte function and health status, early (preimplantation) embryonic development, the optimal window of uterine receptivity for the implanting embryo, the function of the corpus luteum as the main source of progesterone production during the first days of pregnancy, the timing of the subsequent luteoplacental shift in progesterone production, and aberrant reactions of the uterine immune cells to the implanting and recently implanted embryos. In this article, the molecular basis that underlies each of these abnormalities is reviewed and discussed, with the aim to design specific treatment options to be used for each of them.

Sildenafil during the 2nd and 3rd Trimester of Pregnancy: Trials and Tribulations

Sildenafil, a phosphodiesterase 5 inhibitor with a vasodilatory and anti-remodeling effect, has been investigated concerning various conditions during pregnancy. Per indication, we herein review the rationale and the most relevant experimental and clinical studies, including systematic reviews and meta-analyses, when available. Indications for using sildenafil during the second and third trimester of pregnancy include maternal pulmonary hypertension, preeclampsia, preterm labor, fetal growth restriction, oligohydramnios, fetal distress, and congenital diaphragmatic hernia. For most indications, the rationale for administering prenatal sildenafil is based on limited, equivocal data from in vitro studies and rodent disease models. Clinical studies report mild maternal side effects and suggest good fetal tolerance and safety depending on the underlying pathology.

Sildenafil, a Type-5 Phosphodiesterase Inhibitor, Fails to Reverse Myeloid-Derived Suppressor Cell-Mediated T Cell Suppression in Cells Isolated From Tuberculosis Patients

Successful TB treatment is hampered by increasing resistance to the two most effective first-line anti-TB drugs, namely isoniazid and rifampicin, thus innovative therapies focused on host processes, termed host-directed therapies (HDTs), are promising novel approaches for increasing treatment efficacy without inducing drug resistance. We assessed the ability of Sildenafil, a type-5 phosphodiesterase inhibitor, as a repurposed compound, to serve as HDT target, by counteracting the suppressive effects of myeloid-derived suppressor cells (MDSC) obtained from active TB cases on T-cell responsiveness. We confirm that MDSC suppress non-specific T-cell activation. We also show that Sildenafil treatment fails to reverse the MDSC-mediated suppression of T-cell functions measured here, namely activation and proliferation. The impact of Sildenafil treatment on improved immunity, using the concentration tested here, is likely to be minimal, but further identification and development of MDSC-targeting TB host-directed therapies are warranted.

Effectiveness of phosphodiesterase type 5 inhibitors on the treatment of thin endometrium and pregnancy outcomes: An systematic review

Phosphodiesterase type 5 (PDE5) inhibitors are thought to play a role in increasing endometrial thickness and increasing the success rate of pregnancy outcomes. This study was done to investigate the effects of PDE5 inhibitors on infertile women with thin endometrium and pregnancy outcomes. In this systematic review, all randomized controlled trials (RCTs) and observational studies were retrieved from databases including Institute for Scientific Information (ISI), PubMed, and Scopus by interesting keywords. A checklist was designed to collect necessary data and pregnancy outcomes, and the required items were recorded. PDE5 inhibitors through various mechanisms such as induction of vasodilatory effect through the effect on NO/cGMP signaling on vascular smooth muscle, through regulating cells proliferation and induction angiogenesis by increasing the expression of tumor suppressor factor (p53), and vascular endothelial growth factor A (VEGF-A) and downregulating inflammation by downregulating proinflammatory cytokines, affect endometrial thickness that eventually increases and pregnancy outcomes. Although PDE5s inhibitors increase endometrial thickness by different mechanisms, especially in women with thin endometrial, this does not necessarily mean that they induce a positive effect in all situations. However, their positive effects on pregnancy outcome may be affected by the time of administration, type of infertility treatment, underlying diseases such as pelvic disorders and inflammation. So in this regard, there are still ambiguous aspects that required further RCTs study in this area.

Sildenafil Citrate Downregulates PDE5A mRNA Expression in Women with Recurrent Pregnancy Loss without Altering Angiogenic Factors-A Preliminary Study

In our previous study, we showed that sildenafil citrate (SC), a selective PDE5A blocker, modulated NK cell activity in patients with recurrent pregnancy loss, which correlated with positive pregnancy outcomes. It was found that NK cells had a pivotal role in decidualization, angiogenesis, spiral artery remodeling, and the regulation of trophoblast invasion. Thus, in the current study, we determined the effects of SC on angiogenic factor expression and production, as well as idNK cell activity in the presence of nitric synthase blocker L-NMMA. Methods: NK cells (CD56⁺) were isolated from the peripheral blood of 15 patients and 15 fertile women on MACS columns and cultured in transformation media containing IL-15, TGF-β, and AZA—a methylation agent—for 7 days in hypoxia (94% N₂, 1% O₂, 5% CO₂). Cultures were set up in four variants: (1) with SC, (2) without SC, (3) with NO, a synthase blocker, and (4) with SC and NO synthase blocker. NK cell activity was determined after 7 days of culturing as CD107a expression after an additional 4h of stimulation with K562 erythroleukemia cells. The expression of the PDE5A, VEGF-A, PIGF, IL-8, and RENBP genes was determined with quantitative real-time PCR (qRT-PCR) using TaqMan probes and ELISA was used to measure the concentrations of VEGF-A, PLGF, IL-8, Ang-I, Ang-II, IFN–γ proteins in culture supernatants after SC supplementation. Results: SC downregulated PDE5A expression and had no effect on other studied angiogenic factors. VEGF-A expression was increased in RPL patients compared with fertile women. Similarly, VEGF production was enhanced in RPL patients’ supernatants and SC increased the concentration of PIGF in culture supernatants. SC did not affect the expression or concentration of other studied factors, nor idNK cell activity, regardless of NO synthase blockade.

Sildenafil Supplementation for Women Undergoing Infertility Treatments: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The aim of this systematic review and meta-analysis is to summarize data on the effectiveness of Sildenafil supplementation for women undergoing assisted reproduction techniques. This meta-analysis of randomized controlled trials (RCTs) evaluates the effects of Sildenafil administration during infertility treatments compared with a control group in infertile women. Outcomes evaluated were endometrial thickness (ETh) and the clinical pregnancy rate (CPR). The chemical pregnancy rate (ChPR) was also evaluated. Pooled results were expressed as the risk ratio (RR) or mean differences (MD) with a 95% confidence interval (95% CI). Women undergoing ovulation induction who received Sildenafil showed higher ETh and a higher CPR in comparison to controls. In this group, both the ETh and ChPR resulted in significantly higher values only with delayed start administration. Women undergoing fresh or frozen embryo transfer who received Sildenafil showed no significant advantages regarding ETh and CPR in comparison to controls. In this group, we found a significantly higher ChPR in women receiving Sildenafil. A subgroup analysis revealed significant advantages regarding ETh with oral administration for women undergoing fresh or frozen embryo transfer. Sildenafil therapy appears to improve endometrial thickness and pregnancy rate in women undergoing timed intercourses but it resulted not effective in IUI and IVF treatments. Further RCTs with rigorous methodology are still mandatory.

Use of sildenafil and other phosphodiesterase type 5 inhibitors among pregnant women in Scandinavia

INTRODUCTION

For phosphodiesterase type 5 (PDE5) inhibitors, such as sildenafil, the only approved indication in women is for pulmonary arterial hypertension. These drugs are increasingly being proposed and tested for treatment of female infertility and complications in pregnancy. However, the extent of use of PDE5 inhibitors in the general pregnant population over the last decades is unknown. Therefore, we conducted a descriptive cohort study using data from the population health registers in the Scandinavian countries.

MATERIAL AND METHODS

By linking the Medical Birth Registers and the Prescribed Drug Registers in Denmark (1997-2017), Norway (2004-2017), and Sweden (2006-2016), women with filled prescriptions of PDE5 inhibitors in outpatient settings in the 90 days before the date of last menstrual period and/or during pregnancies were identified. With additional linkage to the National Patient Registers, information on maternal, pregnancy, and infant characteristics, co-morbidities, and co-medication was collected and described.

RESULTS

Among over 3 million singleton pregnancies, only 77 were pregnancies in women who had at least one filled prescription of a PDE5 inhibitor within the 90 days before the start of pregnancy to delivery. Prescription fills most often occurred before the last menstrual period and in the first trimester, with very few occurring later in pregnancy. Sildenafil was the most used PDE5 inhibitor. Among pregnant women using PDE5 inhibitors, 44% were 35 years of age or older, eight had a cardiovascular diagnosis, and three specifically had a diagnosis of pulmonary arterial hypertension. Among the infants born to mothers using PDE5 inhibitors, nine were born preterm, six were small-for-gestational age, five had an Apgar score at 5 minutes below 8, 18 were admitted to the Neonatal Intensive Care Unit, and eight had respiratory and cardiovascular conditions.

CONCLUSIONS

Few women used PDE5 inhibitors in outpatient settings before or during pregnancy in the Scandinavian countries in the last decades. Only a small proportion had a diagnosis for pulmonary arterial hypertension, suggesting off-label use in the remaining users. Use was predominantly in mothers over age 35 years. The safety of fetal exposure to sildenafil and other PDE5 inhibitors in pregnancy has not been established. As maternal age continues to increase and additional uses of PDE5 inhibitors are investigated, the safety of these drugs in pregnancy should be thoroughly evaluated.

Decreased Production of TNF-α and IL-6 Inflammatory Cytokines in Non-Pregnant Idiopathic RPL Women Immunomodulatory Effect of Sildenafil Citrate on the Cellular Response of Idiopathic RPL Women

Sildenafil citrate (SC), a PDE5 inhibitor, a drug for erectile dysfunction (ED) and pulmonary hypertension (PAH), was found to exert a positive effect on pregnancy outcomes when administered intravaginally before conception. In our previous studies, sildenafil increased endometrial thickness and significantly decreased peripheral blood NK cell activity after the intravaginal administration in women with recurrent pregnancy loss (RPL). No data are available to confirm the effect of sildenafil on maternal T cell populations involved in shaping fetal-maternal tolerance and NK cell activity. Thus, the present study aimed to establish if SC influences NKT cells or the axis of Th17/Treg cells and Th1/Th2 cytokine production. Materials and methods: Twenty-one healthy fertile women and twenty-two nonpregnant women with idiopathic RPL were studied. The ELISA method was used to evaluate the production of cytokines, including IL-2, IL-12p40, IL-4, IL-10, IL-6, IL-17, IL-21, TGF-β, TNF-α, and IFN-γ in PBMC culture supernatants before and after supplementation with the physiological concentration of SC. The percentages of NKT (CD56⁺CD3⁺CD44⁺CD161⁺), Treg (CD4⁺CD25⁺FOXP3⁺) and Th17 (CD4⁺CD25⁺IL-17A⁺) cells were determined with flow cytometry method. Results: Unexpectedly, we found that the PBMCs of patients with RPL produced a significantly lower level of inflammatory cytokines (TNF-α and IL-6) and a higher level of anti-inflammatory cytokines (TGF-β and IL-10). SC significantly decreased IL-6, IL-12 and increased TGF-β cytokine concentration in fertile women. In the case of RPL patients’ PBMCs, SC improved the production of TNF-α and IL-10. Conclusions: Lower concentration of proinflammatory cytokines in idiopathic RPL women compared to fertile women might suggest the exhaustion of the immune system. The emphasized production of IL-10 by SC partially explains the previously observed downregulation of NK cell activity in RPL patients. The immunomodulatory effect of the drug might be utilized in anti-inflammatory therapies and help achieve positive pregnancy outcomes in women with reproductive failure due to a Th1/Th2 imbalance.

Differences in the Expression of KIR, ILT Inhibitory Receptors, and VEGF Production in the Induced Decidual NK Cell Cultures of Fertile and RPL Women

RESULTS

KIR2DL1 and ILT-2 expression on idNK cells was higher in healthy women than in RPL patients. Sildenafil enhanced NKG2A expression in RPL patients. VEGF concentration was higher in fertile woman idNK cell cultures. idNK cells were more sensitive for necrosis in RPL than in fertile women. SC did not influence VEGF production or idNK cell apoptosis.

CONCLUSIONS

A combination of hypoxia, IL-15, and AZA promotes the conversion of pbNK into idNK cells CD56+CD16--expressing KIR receptors and produces VEGF. Alterations in KIR2DL1 and ILT-2 expression as well as impaired VEGF production were associated with RPL. SC affects NKG2A expression on RPL idNK cells. SC had no effect on VEGF release or idNK cell apoptosis.

Sildenafil beyond erectile dysfunction and pulmonary arterial hypertension: Thinking about new indications

Sildenafil, approved two decades ago, is the inhibitor of phosphodiesterase 5 (PDE5). First of all, it was designated for angina pectoris, but soon it showed a wonderful efficacy in erectile dysfunction (ED) and then pulmonary arterial hypertension (PAH). Due to the distribution of phosphodiesterase (PDE) in almost all organs, maybe it effects other diseases. Hence, a great number of investigations began to understand the role of PDEi in different organs. Preliminary research on sildenafil in cell culture and animal models has yielded promising results. Soon, a greater number of animal researches and clinical trials joined them. The results disclosed sildenafil can have beneficial effects in each organ such as heart, liver, kidney, brain, and intestines. Furthermore, it has significantly improved the prognosis of organ ischemia in various animal models. Clinical trials in several diseases, such as recurrent spontaneous miscarriage, fatty liver disease, bronchopulmonary dysplasia (BPD), heart failure, and premature ejaculation (PE) brought promising results. Although some clinical trials are available on the effects of sildenafil on various diseases, further studies on humans are needed to consolidate the ultimate effects of sildenafil. The aim of this review was to describe the effects of sildenafil on each organ and explain its mechanisms of action. Further, other PDE inhibitors such as tadalafil and vardenafil have been briefly discussed in parts of this review.

Anti-infection mechanism of phosphodiesterase-5 inhibitors and their roles in coronavirus disease 2019 (Review)

Coronavirus disease 2019 (COVID-19) has a variety of impacts on the human body. Severe acute respiratory syndrome coronavirus 2 is the pathogen that causes COVID-19. It invades human tissues through the receptor angiotensin-converting enzyme 2, resulting in an imbalance in the angiotensin II (AngII) level and upregulation of renin-angiotensin system/AngII pathway activity. Furthermore, the binding of AngII to its receptor leads to vasoconstriction, endothelial injury and intravascular thrombosis. In addition, COVID-19 may have adverse effects on male reproductive organs and a marked impact on male reproductive health. Phosphodiesterase-5 inhibitors (PDE5Is) may improve vascular endothelial function, promote testicular and systemic blood circulation and testosterone secretion and enhance epididymal function, as well as sperm maturation and capacitation. PDE5Is may also be of use in the treatment of infectious diseases by enhancing immunity and anti-inflammatory responses and improving vascular endothelial function. Based on the pharmacological mechanism of PDE5Is, they are of unique value in the fight against infectious diseases and may be effective in combination with direct antiviral drugs. The anti-infection mechanisms of PDE5Is and their roles in COVID-19 were reviewed in the present study.

Luteal Phase in Assisted Reproductive Technology

Luteal phase (LP) is the period of time beginning shortly after ovulation and ending either with luteolysis, shortly before menstrual bleeding, or with the establishment of pregnancy. During the LP, the corpus luteum (CL) secretes progesterone and some other hormones that are essential to prepare the uterus for implantation and further development of the embryo, the function known as uterine receptivity. LP deficiency (LPD) can occur when the secretory activity of the CL is deficient, but also in cases of normal CL function, where it is caused by a defective endometrial response to normal levels of progesterone. LPD is particularly frequent in treatments using assisted reproductive technology (ART). Controlled ovarian stimulation usually aims to obtain the highest number possible of good-quality oocytes and requires the use of gonadotropin-releasing hormone (GnRH) analogs, to prevent premature ovulation, as well as an ovulation trigger to achieve timed final oocyte maturation. Altogether, these treatments suppress pituitary secretion of luteinizing hormone (LH), required for the formation and early activity of the CL. In addition to problems of endometrial receptivity for embryos, LPD also leads to dysfunction of the local uterine immune system, with an increased risk of embryo rejection, abnormally high uterine contractility, and restriction of uterine blood flow. There are two alternatives of LPD prevention: a direct administration of exogenous progesterone to restore the physiological progesterone serum concentration independently of the CL function, on the one hand, and treatments aimed to stimulate the CL activity so as to increase endogenous progesterone production, on the other hand. In case of pregnancy, some kind of LP support is often needed until the luteal-placental shift occurs. If LPD is caused by defective response of the endometrium and uterine immune cells to normal concentrations of progesterone, a still poorly defined condition, symptomatic treatments are the only available solution currently available.

Adjuvant Vaginal Use of Sildenafil Citrate in a Hormone Replacement Cycle Improved Live Birth Rates Among 10,069 Women During First Frozen Embryo Transfers

Purpose

To investigate the effects of sildenafil citrate (SC) on live birth rates (LBR) during women undergoing their first frozen embryo transfers (FET) with hormone replacement therapy (HRT).

Patients and Methods

This retrospective cohort study included a total of 10,069 infertile women with adequate endometrial thickness (≥7 mm when progesterone was initiated) in their first FET cycle with hormone replacement therapy. Women received either vaginal SC or no adjuvant during their first transfer cycle depending on patient or physician preference. In the sildenafil group, 1098 women underwent HRT FET with adjuvant vaginal use of SC, and 8971 women were included as controls. The primary outcome measure was LBR, defined as the likelihood of live birth per transfer cycle. Endometrial thickness (EMT), implantation, chemical pregnancy, clinical pregnancy, miscarriage, ongoing pregnancy, birth weight and preterm delivery (PTB) were also recorded.

Results

Baseline characteristics were comparable between the two groups. In the crude analysis, the unadjusted LBR was significantly higher in the vaginal SC group (scHRT-FET) than in the control group (HRT-FET) (40.3% vs 36.1%). After adjustment for 12 pregnancy-related confounding factors, logistic regression analysis showed that LBR remained significantly higher in the scHRT-FET group than in the HRT-FET group (adjusted odds ratio [aOR] 1.31, 95% confidence interval [CI] 1.14–1.49). Furthermore, after adjustment, the ongoing pregnancy rate was significantly higher (aOR 1.29, 95% CI 1.13–1.47), and the miscarriage rate was significantly lower (aOR 0.58, 95% CI 0.43–0.77), in the scHRT-FET group compared to the HRT-FET group. Adjuvant vaginal use of SC did not increase the endometrial thickness and had no significant effect on birth weight or PTB.

Conclusion

Adjuvant vaginal use of SC in HRT FET was associated with higher LBR and improved pregnancy outcomes in an infertile population with adequate endometrial thickness. The beneficial effect of SC may be due not to an increase in EMT but instead to improve endometrial blood flow and receptivity, which might merit clinicians’ attention for improving general IVF practices.

Myeloid-Derived Suppressor Cells as Target of Phosphodiesterase-5 Inhibitors in Host-Directed Therapeutics for Tuberculosis

Resistance toward current and new classes of anti-tuberculosis (anti-TB) antibiotics are rapidly emerging; thus, innovative therapies focused on host processes, termed host-directed therapies (HDTs), are promising novel approaches for shortening therapy regimens without inducing drug resistance. Development of new TB drugs is lengthy and expensive, and success is not guaranteed; thus, alternatives are needed. Repurposed drugs have already passed Food and Drug Administration (FDA) as well as European Medicines Agency (EMA) safety requirements and may only need to prove efficacy against Mycobacterium tuberculosis (M.tb). Phosphodiesterases (PDEs) hydrolyze the catalytic breakdown of both cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) to their inactive mononucleotides. Advances in molecular pharmacology have identified 11 PDE families; and the success of sildenafil, a PDE-5 selective inhibitor (PDE-5i), in treating pulmonary hypertension and erectile dysfunction has invigorated research into the therapeutic potential of selective PDE inhibitors in other conditions. Myeloid-derived suppressor cells (MDSCs) suppress anti-TB T-cell responses, likely contributing to TB disease progression. PDE-5i increases cGMP within MDSC resulting in the downregulation of arginase-1 (ARG1) and nitric oxide synthase 2 (NOS2), reducing MDSC's suppressive potential. The effect of this reduction decreases MDSC-induced T-cell-suppressive mechanisms. This review highlights the possibility of HDT targeting of MDSC, using a PDE-5i in combination with the current TB regimen, resulting in improved TB treatment efficacy.

The Effect of Vaginal Sildenafil on The Outcome of Assisted Reproductive Technology Cycles in Patients with Repeated Implantation Failures: A Randomized Placebo-Controlled Trial

Background

The aim of this study was to investigate the effects of vaginal sildenafil on the outcome of patients with at least two unsuccessful in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) attempts.

Materials and Methods

In this randomized placebo-controlled trial study, a total of 66 infertile women aged ≤38 years, with a history of normal ovarian reserve, two prior consecutive failed IVF/ICSI attempts, human chorionic gonadotropin (hCG) day endometrial thickness <7 mm in all prior IVF/ICSI cycles, normal endometrial appear- ance by either hysteroscopy, hysterosonography, or hysterosalpingography enrolled in this study. The conventional gonadotropin-releasing hormone (GnRH) protocol was used for ovarian stimulation. The patients were randomly divided into three groups: vaginal sildenafil (suppository-100 mg/daily), vaginal placebo/sildenafil (suppository-100 mg/daily), and vaginal placebo (suppository). Each patient underwent colour Doppler ultrasound on day 14 of their previous cycle to investigate any abnormalities in the uterus and adnexa. Endometrial thickness, echo pattern, uterine artery resistance, and pulsatility indices were recorded pre- and post-treatment. The primary outcome measures were implantation, chemical and clinical pregnancy rates. For data analysis, SPSS version 20 software was used. In all tests, the significance level was considered less than 0.05.

Results

There was no significant difference between three groups in endometrial thickness on the hCG injection day. The chemical pregnancy in women who received sildenafil (alone or in combination with placebo) showed a two-fold increase in comparison to the placebo group. This increase was clinically meaningful, but according to sample size, it was statistically non-significant. The results of our study showed that the implantation was higher in women who received placebo/sildenafil compared to the other groups. The abortion rate was not statistically significant among the groups.

Conclusion

Vaginal sildenafil may conceivably improve chemical pregnancy rates in repeated IVF failure patients. Further randomized clinical trials using oral or vaginal sildenafil with higher sample size are recommended (Registra- tion number: NCT03192709).

Endometrium receptivity in premature ovarian insufficiency - how to improve fertility rate and predict diseases?

More empathized approach is required and is obligatory to women with premature ovarian insufficiency (POI) interested for pregnancy. In order to improve fertility rate in POI patients our suggestions would be: (1) To decrease FSH value to 10-15 IU/L by increasing estrogen. Oocyte donation can be suggested after a minimum of six month interval from FSH between 10-15 IU/L and when no dominant follicles are found. (2) To perform oral glucose tolerance test (OGTT). Insulin sensitizing agents has to be included, when indicated, 3-6 month before pregnancy. (3) TSH has to be 1-2.5 mM/L during 3-6 months before pregnancy. (4) Tests for thrombophyllia (Leiden V, FII, MTHFR, PAI) have to be obligatory. They are less expensive than those repeated in vitro fertilizations. Therapy has to be included according to the indications. (5) In order to regulate disturbed immune response in POI patients with endometriosis oral contraceptive therapy is needed for atleast six months prior to the pregnancy. (5) Encourage the patients and advice them about healthy life style and eating habits. (6) Add other drugs, when they are indicated. Complex interplay between endocrine, immunological, haematological, and psychological factors are very often underdetected in POI patients. It is very important to find out the real time for oocyte donation after correcting all the disturbances, improving endometrium receptivity and reaching women's acceptable psychological status. Untreated disturbances induce cardiovascular diseases, diabetes mellitus, thyroid diseases, coagulopathioes etc.

Novel in situ gelling vaginal sponges of sildenafil citrate-based cubosomes for uterine targeting

Sildenafil citrate (SIL), a type 5-specific phosphodiesterase inhibitor, demonstrates valuable results in the management of infertility in women; however, the absence of vaginal dosage form in addition to the associated oral adverse effects minimize its clinical performance. The present study is concerned with SIL uterine targeting following intravaginal administration via optimization of cubosomal in situ gelling sponges (CIS). An emulsification method was employed for preparation of cubosomal dispersions incorporating glyceryl monooleate as a lipid phase and poloxamer 407 as a surfactant with or without polyvinyl alcohol as a stabilizer. Cubosomes were estimated regarding entrapment efficiency (EE%), particle size, and in vitro drug release. Chitosan (2% w/w) was incorporated into the optimum formulation and then lyophilized into small sponges. For the CIS, in vivo histopathological and pharmacokinetic studies were conducted on female Wistar rats and compared with intravaginal free SIL sponges (FIS) and oral SIL solution. SIL-loaded cubosomes showed EE% ranging between 32.15 and 72.01%, particle size in the range of 150.81–446.02 nm and sustained drug release over 8 h. Histopathological study revealed a significant enlargement in endometrial thickness with congestion and dilatation of endometrial blood vessels in intravaginal CIS compared to intravaginal FIS and oral-treated groups. The pharmacokinetic study demonstrated higher AUC_0–∞ and C_max with oral administration compared to intravaginal CIS or intravaginal FIS indicating potential involvement of first uterine pass effect after intravaginal administration. Finally, intravaginal CIS could be considered as a promising platform for SIL uterine targeting with minimized systemic exposure and side effects.

Is there a relationship between phosphodiesterase type 5 inhibitors and biochemical recurrence after radical prostatectomy: a systematic review and meta-analysis

PURPOSE

Conduct a systematic review and meta-analysis of studies to evaluate the association between the use of PDE5I and biochemical recurrence (BCR) after radical prostatectomy (RP).

METHODS

We searched Embase (from 1996 to Feb 2018), PubMed (from 1996 to Feb 2018), and Cochrane library (from 1999 to Feb 2018), then manually searched the reference lists of key retrieved articles. Original studies that reported the risk of postoperative BCR for PDE5I users, as compared with non-PDE5I users, were included. Data including the characteristic of participants, the risk of BCR after RP and key criteria of study quality were collected. The pooled relative risks (RRs) were calculated with random-effects model.

RESULTS

A total of 5 cohort studies and 1 case-control study were conducted for data analysis (a total of 17752 participants). Only 1 cohort study reported adjusted RR greater than 1 (range for all derived RRs, 0.7-1.47). The meta-analysis revealed that the PDE5I users had no higher risk of BCR after RP (RR = 1.04, 95% confidence interval [CI], 0.79-1.36). Sensitivity analysis showed that the remaining pooled RR and 95% CI were not changed significantly by omitting each study. In addition, the 5-year BCR rate had no significant difference between PDE5I users and non-PDE5I users.

CONCLUSIONS

Our meta-analysis indicated that PDE5I treatment in men following RP did not increase the risk of BCR. The results preliminarily suggested that the use of PDE5I for erectile dysfunction after RP was oncologically safe. Nevertheless, more large sample cohort studies are needed to validate this conclusion.

Phosphodiesterase type 5 and cancers: progress and challenges

Cancers are an extraordinarily heterogeneous collection of diseases with distinct genetic profiles and biological features that directly influence response patterns to various treatment strategies as well as clinical outcomes. Nevertheless, our growing understanding of cancer cell biology and tumor progression is gradually leading towards rational, tailored medical treatments designed to destroy cancer cells by exploiting the unique cellular pathways that distinguish them from normal healthy counterparts. Recently, inhibition of the activity of phosphodiesterase type 5 (PDE5) is emerging as a promising approach to restore normal intracellular cyclic guanosine monophosphate (cGMP) signalling, and thereby resulting into the activation of various downstream molecules to inhibit proliferation, motility and invasion of certain cancer cells. In this review, we present an overview of the experimental and clinical evidences highlighting the role of PDE5 in the pathogenesis and prevention of various malignancies. Current data are still not sufficient to draw conclusive statements for cancer patient management, but could provide further rational for testing PDE5-targeting drugs as anticancer agents in clinical settings.

Sildenafil Can Affect Innate and Adaptive Immune System in Both Experimental Animals and Patients

Sildenafil, a type 5 phosphodiesterase inhibitor (PDE5-I), is primarily used for treating erectile dysfunction. Sildenafil inhibits the degradation of cyclic guanosine monophosphate (cGMP) by competing with cGMP for binding site of PDE5. cGMP is a secondary messenger activating protein kinases and a common regulator of ion channel conductance, glycogenolysis, and cellular apoptosis. PDE5 inhibitors (PDE-Is) found application in cardiology, nephrology, urology, dermatology, oncology, and gynecology. Positive result of sildenafil treatment is closely connected with its immunomodulatory effects. Sildenafil influences angiogenesis, platelet activation, proliferation of regulatory T cells, and production of proinflammatory cytokines and autoantibodies. Sildenafil action in humans and animals appears to be different. Surprisingly, it also acts differently in males and females organisms. Although the immunomodulatory effects of PDE5 inhibitors appear to be promising, none of them reached the point of being tested in clinical trials. Data on the influence of selective PDE5-Is on the human immune system are limited. The main objective of this review is to discuss the immunomodulatory effects of sildenafil in both patients and experimental animals. This is the first review of the current state of knowledge about the effects of sildenafil on the immune system.

Useful Implications of Low-dose Long-term Use of PDE-5 Inhibitors

INTRODUCTION

Phosphodiesterase type 5 (PDE-5) hydrolyzes cyclic guanylate monophosphate (cGMP) specifically to 5' GMP, promoting successful corporeal vascular relaxation and penile erection during sexual stimulation. Oral PDE-5 inhibitors such as sildenafil, vardenafil, tadalafil, and avanafil have provided noninvasive, effective, well-tolerated treatment for erectile dysfunction (ED) patients and, at the same time, stimulated both academic and clinical interests. Lately, some oral PDE-5 inhibitors were released as low-dose preparations with the concept of potential daily administration and long-term use.

AIM

To highlight the possible potential implications of low-dose long-term use of PDE-5 inhibitors.

METHOD

A systematic review was carried out until December 2015 based on a search of all concerned articles in MEDLINE, medical subjects heading (MeSH) databases, Scopus, The Cochrane Library, EMBASE, and CINAHL databases without language restriction. Key words used to assess the outcome and estimates for concerned associations were: PDE-5 inhibitors; erectile dysfunction; low-dose; long-term; sildenafil; tadalafil; vardenafil; avanafil.

MAIN OUTCOME MEASURES

Demonstrating different implications for low-dose long-term use of PDE-5 inhibitors.

RESULTS

Low-dose and/or long-term use of PDE-5 inhibitors was shown to put forth beneficial sound effects in different medical implications with potentials that could be extended for different utilities. These implications included sexual, urogenital, cardiovascular, pulmonary, cutaneous, gastrointestinal, and reproductive, as well as neurological disorders. However, it is evident that most potential appliances were carried out experimentally on preclinical studies with off-label indications.

CONCLUSION

Making use of and exploring low-dose and/or long-term use of several PDE-5 inhibitors for their possible implications seem to be valuable in different medical disorders. Increased knowledge of the drug characteristics, comparative treatment regimens, optimal prescribing patterns, and well-designed clinical trials are needed before these agents can be recommended for use.

Let’s rethinking about the safety of phosphodiesterase type 5 inhibitor in the patients with erectile dysfunction after radical prostatectomy

As the radical prostatectomy (RP) for the patient diagnosed as localized prostate cancer has been increasing, erectile dysfunction (ED) associated with RP is increased and ED after RP is a significant risk factor to reduce the quality of life for the patient after RP. Therefore, the treatment concept called penile rehabilitation was introduced and phosphodiesterase type 5 inhibitor (PDE5I) is used widely for the prostate cancer patient after RP. Generally PDE5I is considered as safe and effective drug for the prostate cancer patient after RP. Recently, a report against the general opinion that PDE5I use is safe in the patient with prostate cancer was reported and the analysis of 5-yr biochemical recurrence-free survival after RP between the PDE5I users and non-PDE5I users after bilateral nerve sparing RP showed decreased 5-yr biochemical recurrence-free survival in the PDE5I users. In addition, a longitudinal cohort study reported that sildenafil, a kind of PDE5I, use might be associated with the development of melanoma and this result suggested the possibility of adverse effect of PDE5I on some kinds of cancers as well as prostate cancer. Moreover, the studies to evaluate the influence of nitric oxide (NO) and guanosine monophosphate (cGMP) signaling pathway associated with PDE5 showed both cancer reduction and cancer development. Therefore, the role of NO and cGMP signaling pathway in cancer was reviewed based on the previous studies and suggested the necessity of further clinical studies concerning about the safety of PDE5I in prostate cancer.

Effects of Sildenafil Citrate and Heparin Treatments on Placental Cell Morphology in a Murine Model of Pregnancy Loss

Lipopolysaccharide (LPS) injections during pregnancy are well established as models for pregnancy complications, including fetal growth restriction (FGR), thrombophilia, preterm labor and abortion. Indeed, inflammation, as induced by LPS injection has been described as a pivotal factor in cases of miscarriage related to placental tissue damage. The phosphodiesterase-5 inhibitor sildenafil (Viagra®) is currently used to treat FGR cases in women, while low-molecular weight heparin (Fragmin®) is a standard treatment for recurrent miscarriage (RM). However, the pathways and cellular dynamics involved in RM are not completely understood. The aim of this study was to evaluate the protective effect of sildenafil and dalteparin in a mouse model of LPS-induced abortion. Histopathology, ultrastructural analysis and immunofluorescence for P-selectin were studied in two different placental cell types: trophoblast cells and labyrinth endothelial cells. Treatment with sildenafil either alone or in combination with heparin showed the best response against LPS-induced injury during pregnancy. In conclusion, our results support the use of these drugs as future therapeutic agents that may protect the placenta against inflammatory injury in RM events. Analyses of the ultrastructure and placental immunophysiology are important to understand the mechanism underlying RM. These findings may spark future studies and aid in the development of new therapies in cases of RM.

Phosphodiesterase Type 5 Inhibitor Use and Disease Recurrence After Prostate Cancer Treatment

BACKGROUND

Phosphodiesterase type 5 inhibitor (PDE5i) use is common for management of erectile dysfunction. Single-institution studies have reported conflicting data on the relationship between PDE5i use and biochemical recurrence of prostate cancer (BCR) after radical prostatectomy.

OBJECTIVE

To evaluate the association between PDE5i use and BCR after radical prostatectomy and radiation therapy in a nationwide population-based cohort.

DESIGN, SETTING, AND PARTICIPANTS

This was a nested case-control study using the National Prostate Cancer Register of Sweden linked to the Prescribed Drug Register. Among men with localized prostate cancer who underwent primary radical prostatectomy or radiation therapy during 2006-2007 with 5 yr of follow-up, 293 had BCR after treatment (cases). For each case we identified 20 BCR-free controls (n=5767) using incidence density sampling.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Multivariable conditional logistic regression was used to examine the association between PDE5i use and BCR risk. Separate multivariable models including clinical variables for men undergoing prostatectomy or radiotherapy and including surgical pathology after prostatectomy were also analyzed.

RESULTS AND LIMITATIONS

PDE5i use was not associated with BCR after radical prostatectomy (odds ratio [OR] 0.78, 95% confidence interval [CI] 0.59-1.03) or radiation therapy (OR 0.98, 95% CI 0.49-1.97) after adjusting for marital status, education, income, prostate-specific antigen, clinical stage, Gleason score, and proportion of positive biopsies. Results were similar after additional adjustment for surgical pathology (OR 0.86, 95% CI 0.64-1.16). Men whose cumulative number of PDE5i pills was above the median had a slightly lower BCR risk after prostatectomy in the clinical model, and no difference in BCR risk after adjustment for pathologic tumor features.

CONCLUSIONS

Our results from a population-based cohort suggest that BCR risk is not higher among men using PDE5i after prostate cancer treatment.

PATIENT SUMMARY

Erectile dysfunction medications are not associated with a higher risk of disease recurrence after prostate cancer treatment.

Sildenafil (Viagra®) blocks inflammatory injury in LPS-induced mouse abortion: A potential prophylactic treatment against acute pregnancy loss?

INTRODUCTION

Recurrent pregnancy losses (RPL) are common women's health issues. Inflammatory and thrombotic events have been associated with RPL including excessive production of cytokines, in particular TNF-α. However, mechanisms behind gestational losses are not yet fully understood. Sildenafil inhibits phosphodiesterase Type-5 (PDE5). This drug increases intracellular cyclic guanosine monophosphate, having vasodilatory and, more recently described, anti-inflammatory properties. PDE5 is present in murine and human uterus and placenta. Sildenafil is already used clinically for treatment of human fetal growth restriction (FGR). Our objective was to determine if Sildenafil alone or in combination with Heparin had protective effects in pregnant Swiss albino challenged to abort by lipopolysaccharide (LPS).

METHODS

Treatments (Sildenafil (50 mg/kg/day), Heparin (500 IU/Kg/day) or Sildenafil + Heparin at the same doses) were initiated the morning of copulation plug detection (gestational day (gd0)). On the 15th day of pregnancy, an intra-peritoneal injection of LPS (100 μg/kg) was administered. Untreated, pregnant mice challenged by LPS served as controls.

RESULTS

Assessments at 48 h after LPS revealed that Sildenafil + Heparin prevented fetal loss. Early assessments at 2 h after LPS indicated that the pretreatments prevented induction of inflammatory cytokine production (TNF-α, IL-1β/NF-κβ) and preserved placental histopathology.

DISCUSSION

Combined Sildenafil + Heparin therapy was superior to either treatment alone in most analyses. The known safety of Sildenafil and Heparin in human pregnancy suggests that usage of these combined agents may be of value for treatment of patients with impending pregnancy loss or prophylactically in women with a history of recurrent miscarriages.

Clinical pregnancy after uterus transplantation

OBJECTIVE

To present the first clinical pregnancy after uterus transplantation.

DESIGN

Case study.

SETTING

Tertiary center.

PATIENT(S)

A 23-year-old Mayer-Rokitansky-Kuster-Hauser syndrome patient with previous vaginal reconstruction and uterus transplantation.

INTERVENTION(S)

Eighteen months after the transplant, the endometrium was prepared for transfer of the thawed embryos.

MAIN OUTCOME MEASURE(S)

Implantation of embryo in an allografted human uterus.

RESULT(S)

The first ET cycle with one day 3 thawed embryo resulted in a biochemical pregnancy. The second ET cycle resulted in a clinical pregnancy confirmed with transvaginal ultrasound visualization of an intrauterine gestational sac with decidualization.

CONCLUSION(S)

We have presented the first clinical pregnancy in a patient with absolute uterine infertility after uterus allotransplantation. Although the real success is the delivery of a healthy near-term baby, this clinical pregnancy is a great step forward and a proof of concept that the implantation phase works.

Nitric oxide synthases and tubal ectopic pregnancies induced by Chlamydia infection: basic and clinical insights

Human ectopic pregnancy (EP) remains a common cause of pregnancy-related first trimester death. Nitric oxide (NO) is synthesized from L-arginine by three NO synthases (NOS) in different tissues, including the Fallopian tube. Studies of knockout mouse models have improved our understanding of the function of NOS isoforms in reproduction, but their roles and specific mechanisms in infection-induced tubal dysfunction have not been fully elucidated. Here, we provide an overview of the expression, regulation and possible function of NOS isoforms in the Fallopian tube, highlighting the effects of infection-induced changes in the tubal cellular microenvironment (imbalance of NO production) on tubal dysfunction and the potential involvement of NOS isoforms in tubal EP after Chlamydia trachomatis genital infection. The non-equivalent regulation of tubal NOS isoforms during the menstrual cycle suggests that endogenous ovarian steroid hormones regulate NOS in an isoform-specific manner. The current literature suggests that infection with C. trachomatis induces an inflammatory response that eventually leads to tubal epithelial destruction and functional impairment, caused by a high NO output mediated by inducible NOS (iNOS). Therefore, tissue-specific therapeutic approaches to suppress iNOS expression may help to prevent ectopic implantation in patients with prior C. trachomatis infection of the Fallopian tube.

First successful pregnancy after addition of enoxaparin to sildenafil and etanercept immunotherapy in woman with fifteen failed IVF cycles - case report

PROBLEM

Does addition of enoxaparin to sildenafil and etanercept immunotherapy improve IVF outcome?

METHODS

Report of a striking case with 15 IVF failures.

RESULT

When enoxaparin was added, the 16th IVF cycle generated a healthy male baby.

CONCLUSIONS

Combination therapy that includes a heparin may allow successful IVF outcome and this issue merits further study.

Biochemical role of intravaginal sildenafil citrate as a novel antiabortive agent in unexplained recurrent spontaneous miscarriage: first clinical study of four case reports from Egypt

BACKGROUND

Many factors have been implicated in the pathogenesis of unexplained recurrent spontaneous miscarriage (URSM).

METHODS

The objective of this preliminary clinical study was to verify whether intravaginal sildenafil citrate tablets (25 mg intravaginally, 4 times/day for 24 days) are effective as a novel treatment of threatened miscarriage in patients with a history of URSM (n=4). We also evaluated changes in the concentrations of some antioxidants, the percent expression of cells positive for tumor necrosis factor-alpha (TNF-alpha), CD56+T-cells [CD3+CD56+ natural killer cells (NKT cells) (cluster differentiation 3, 56 NKT cells)], which express one of the NK cell markers, and uterine artery pulsatility index (PI). We compared these results with healthy women in their first trimester of pregnancy (FTP n=4).

RESULTS

Sildenafil improved the measured antioxidants concentrations [total antioxidant capacity (TAC), glutathione S-transferase (GSH-S-T) and catalase (CAT), superoxide dismutase (SOD)], and improved oxidative stress by reducing malondialdehyde (MDA) and nitric oxide (NO) in the four patients under investigation. The improvement in antioxidants was close to concentrations seen in women in their FTP. The four patients had progressed to their third trimester of pregnancy using this novel application. The percentage of [CD3+CD56+ NKT cells] and TNF-alpha in peripheral blood was higher in URSM patients compared to women in their FTP. However, concentrations were greatly reduced and improved after sildenafil administration. We demonstrated that intravaginal sildenafil citrate tablets can reduce vasoconstriction by increasing blood flow through relaxation of uterine arteries as indicated from measured PI in URSM patients.

CONCLUSIONS

We conclude that intravaginal sildenafil citrate tablets used as suppositories might be a novel, interesting, safe antiabortive option in the treatment of threatened miscarriage in patients with a history of URSM. We are the first to report this novel clinical application in four case reports in Egypt.