The effect of 6-mercaptopurine on early human placental explants

Exploring maternal-fetal interface with in vitro placental and trophoblastic models

The placenta, being a temporary organ, plays a crucial role in facilitating the exchange of nutrients and gases between the mother and the fetus during pregnancy. Any abnormalities in the development of this vital organ not only lead to various pregnancy-related disorders that can result in fetal injury or death, but also have long-term effects on maternal health. In vitro models have been employed to study the physiological features and molecular regulatory mechanisms of placental development, aiming to gain a detailed understanding of the pathogenesis of pregnancy-related diseases. Among these models, trophoblast stem cell culture and organoids show great promise. In this review, we provide a comprehensive overview of the current mature trophoblast stem cell models and emerging organoid models, while also discussing other models in a systematic manner. We believe that this knowledge will be valuable in guiding further exploration of the complex maternal-fetal interface.

Increased Incidence of Villitis in Placentas Exposed to Chemotherapy During Pregnancy: Is There a Correlation?

We have identified 9 pregnant patients who were diagnosed with malignancy and initiated chemotherapy during their second trimester (cervical cancer [n = 3], leukemia [n = 3], breast cancer [n = 2], and Hodgkin's lymphoma [n = 1]). Five of the patients' placentas were small for gestational age (SGA). Pathologic examination revealed inflammatory changes in 4 of the placentas: 2 from the SGA placentas and 2 from non-SGA placentas. Examination revealed 3 placentas with villitis of unknown etiology (VUE) and 1 with intervillositis; all were negative for bacterial and viral cultures and by immunohistochemical (IHC) stains. In the VUE cases, IHC stains showed positivity of CD25+/FOXP3+ with focal positivity and CD3 and CD4 IHC were focally to strongly positive. Literature suggests that the use of chemotherapy during pregnancy can be detrimental to both the mother and the fetus; however, there has been limited focus on the effects of chemotherapy on the placenta. We suggest that the inflammatory process noted in the placentas is due to chemotherapy-induced toxic effects.

The Impact of Immunosuppressive Drugs on Human Placental Explants

The use of immunosuppressive drugs guarantees the vitality of the graft and allows gestation in spite of intercurrences such as prematurity and intrauterine growth restriction. However, little is known about the direct effects of immunosuppressive drugs on placental cells. We investigated the effects of immunosuppressive drugs in the chorionic villous explants from human term placentas of healthy gestations. Human placental explants from term gestations (37-39 week gestational age, n = 12) were exposed to cyclosporine A (CSA, 0, 62.5, 125, 1250 ng/mL) or azathioprine (AZA, 0, 5, 10, 100 ng/mL) separately or, in combination for up to 48 hours. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays showed a significant decrease in the explant metabolic activity between AZA and the control group (24 hours, 100 ng/mL, 48 hours, all concentrations, P < .005). Cyclosporin A (CsA) reduced cell activity when associated with AZA (48 hours, P < .005). Fibrinoid deposits increased in AZA-treated explants alone (5 ng/mL, 48 hours; 10 ng/mL, 24-48 hours; P < .005) or when associated with CsA (10 AZA/125 CsA, P < .05), whereas in CsA treatment alone, there was an augment in syncytial knots (24-48 hours, P < .005). The sFLT1 gene (24 hours, P < .05) and protein ( P < .005) expression increased in AZA and CsA-treatments separately or in combination ( P < .05). Placental growth factor increased in AZA (24 hours, 10 ng/mL) and CsA (125 ng/mL; P < .05). In conclusion, our data indicate that AZA primarily acts on the villous metabolism, perturbing placental homeostasis. Since these drugs may alter the balance of angiogenic factors in its selection for clinical application, their impact on the behavior of placental villous should be considered.

Haematological malignancies in pregnancy: An overview with an emphasis on thrombotic risks

With increase of maternal age, the incidence of haematological malignancies during pregnancy is rising and posing diagnostic and treatment challenges. Lymphoma is the fourth most common malignancy diagnosed in pregnancy; Hodgkin lymphoma is more frequent in pregnant women than non-Hodgkin lymphoma (NHL). The proportion of highly aggressive lymphomas in pregnant women is significantly higher than in non-pregnant women of reproductive age. Reproductive organ involvement is observed in almost half of pregnant women with NHL. The association of acute leukaemia and pregnancy is infrequent and it is assumed that pregnancy does not accelerate the disease course. Both cancer and pregnancy induce a procoagulant state which can lead to maternal venous thromboembolism (VTE) and placental occlusion. Pregnancy in woman with myeloproliferative neoplasms (MPN) promotes thrombotic environment, associating with an augmented risk of placental thrombosis, intrauterine growth retardation or loss and maternal thrombotic events.Haematological malignancies during pregnancy often require urgent diagnosis and management and are associated with potential adverse fetal outcomes. Most chemotherapeutic agents are teratogenic and should be avoided during the first trimester. Their use during the second and third trimesters may cause intrauterine growth restriction, premature birth and intrauterine fetal death. All chemotherapeutic drugs should be administered only after a detailed discussion with the patient and with close fetal monitoring. Chemotherapy and biological agents might also augment thrombotic risk. Guidelines for VTE prophylaxis in pregnant women with hematologic malignancies, apart from MPN, are currently unavailable, and therefore, clinical judgment should be made in each case.

Successful pregnancy and delivery in a patient with chronic myeloid leukemia: a case report and review of the literature

Introduction

Complications associated with chronic myeloid leukemia (CML) during pregnancy are rare, and management is challenging because very limited data are available on this patient group.

Case description

We herein report a successful pregnancy and delivery in a patient diagnosed with CML. The patient was treated with imatinib (400 mg/day) as a first-line therapy. However, she became pregnant while she was in complete hematological remission and had a complete cytogenetic response. Because she elected to continue the pregnancy to term, imatinib treatment was stopped after 5 months of gestation and the patient was then treated with interferon-alpha for the remainder of her pregnancy. However, the CML did not relapse. She successfully gave birth to a male infant at 39 weeks by cesarean section with no adverse sequelae or malformations.

Discussion and Evaluation

The treatment of pregnant women with CML is difficult because of few available therapeutic options and limited data regarding the potential harm to the fetus. Conception should be planned and TKI therapy discontinued in female patients during pregnancy, and individual risks need to be considered when an unplanned pregnancy occurs.

Conclusions

Our experience will be useful for counseling patients inadvertently exposed to tyrosine kinase inhibitors such as imatinib during pregnancy.

Quantifying trophoblast migration: In vitro approaches to address in vivo situations

When trophoblasts migrate and invade in vivo, they do so by interacting with a range of other cell types, extracellular matrix proteins, chemotactic factors and physical forces such as fluid shear stress. These factors combine to influence overall trophoblast migration and invasion into the decidua, which in turn determines the success of spiral artery remodelling, and pregnancy itself. Our understanding of these important but complex processes is limited by the simplified conditions in which we often study cell migration in vitro, and many discrepancies are observed between different in vitro models in the literature. On top of these experimental considerations, the migration of individual trophoblasts can vary widely. While time-lapse microscopy provides a wealth of information on trophoblast migration, manual tracking of individual cell migration is a time consuming task that ultimately restricts the numbers of cells quantified, and thus the ability to extract meaningful information from the data. However, the development of automated imaging algorithms is likely to aid our ability to accurately interpret trophoblast migration in vitro, and better allow us to relate these observations to in vivo scenarios. This commentary discusses the advantages and disadvantages of techniques commonly used to quantify trophoblast migration and invasion, both from a cell biology and a mathematical perspective, and examines how such techniques could be improved to help us relate trophoblast migration more accurately to in vivo function in the future.

The effect of heat shock protein 27 on extravillous trophoblast differentiation and on eukaryotic translation initiation factor 4E expression

Heat shock protein (HSP27) is expressed in human placentae. Previously, we showed that HSP27 is expressed in the villous cell column of first trimester placental explants and in extravillous trophoblast (EVT) cells. EVT differentiation is accompanied by increased motility, matrix metalloproteinase (MMP) activity, decreased proliferation and expression of specific markers such as HLAG and CD9. HSP27 regulates cell apoptosis, migration, protein stability and the availability of eukaryotic translation initiation factors, such as eukaryotic translation initiation factor 4E (eIF4E). eIF4E supports trophoblast cell proliferation and survival. We wanted to explore the effect of HSP27 silencing on trophoblast cell phenotype, EVT markers and eIF4E expression and regulators [4E-binding protein (4E-BP1) and MAP kinase-interacting kinase (MNK1)]. This study evaluated the effect of HSP27 siRNA on placental explant and HTR-8/SVneo migration, MMP activity/mRNA, cell death, cell cycle, HLAG/CD9 levels, and eIF4E and its regulators' total and phosphorylated levels. Furthermore, we evaluated HSP27 levels in placentae exposed to ribavirin, which triggers EVT differentiation. We found that HSP27 silencing increased cell death in HTR-8/SVneo and placental explants. Furthermore, it reduced HTR-8/SVneo migration and EVT outgrowth from the explants (P < 0.05), MMP2 activity and expression of EVT markers HLAG and CD9 (in placental explants and HTR-8/SVneo, respectively, P < 0.05). Induction of EVT differentiation by ribavirin elevated HSP27 levels. Finally, HSP27 silencing in both HTR-8/SVneo and placental explants reduced eIF4E levels (33 and 28%, respectively, P < 0.05) and the levels of its regulators 4E-BP1 and MNK1 (37 and 32%, respectively, done on HTR-8/SVneo only), but not their phosphorylated forms. Altogether, our results suggest that HSP27 contributes to EVT cell differentiation.

How I treat leukemia during pregnancy

Leukemia in pregnancy remains a challenging therapeutic prospect. The prevalence is low at ∼1 in 10 000 pregnancies, and as a result data are limited to small retrospective series and case reports, rendering evidence-based recommendations for management strategies difficult. The management of the leukemias in pregnancy requires close collaboration with obstetric and neonatology colleagues as both the maternal and fetal outcomes must be taken into consideration. The decision to introduce or delay chemotherapy must be balanced against the impact on maternal and fetal survival and morbidity. Invariably, acute leukemia diagnosed in the first trimester necessitates intensive chemotherapy that is likely to induce fetal malformations. As delaying treatment in this situation is usually inappropriate, counseling with regard to termination of pregnancy is often essential. For chronic disease and acute leukemia diagnosed after the second trimester, therapeutic termination of the pregnancy is not inevitable and often, standard management approaches similar to those in nongravid patients can be used. Here, the management of the acute and chronic leukemias will be addressed.

Obstetrical, fetal and postnatal effects of gestational antiblastic chemotherapy: how to counsel cancer patients

At least one in a thousand pregnancies is complicated by cancer and, as the maternal age at pregnancy increases, numbers are growing. If chemotherapy cannot be postponed, both doctors and patients face complex medical and ethical issues. There is a conflict between optimal maternal therapy and fetal wellbeing. Treatment during the first trimester increases the risk of congenital malformations, spontaneous abortions and fetal death. Second and third trimester exposure is less risky, but it can cause intrauterine growth retardation and low birth weight. Other effects on pregnancy after the first trimester include premature birth, stillbirth, impaired functional development, myocardial toxicity and myelosuppression. Counseling and management of these cases are difficult, because literature is mostly represented by case reports or retrospective series while randomized prospective studies or guidelines are lacking. Moreover, personal experience is often scanty due to the rarity of the condition. This article reviews the available data regarding the different aspects of systemic treatment of cancer during pregnancy to help oncologist and obstetricians in counseling their patients and treat them accordingly.

Antiblastic treatment, for solid tumors, during pregnancy: a crucial decision

Cancer is the second leading cause of death during the reproductive years complicating between 0.02 percent and 0.1 percent of pregnancies. The incidence is expected to rise with the increase in age of childbearing. The most common types of pregnancy-associated cancers are: cervical cancer, breast cancer, malignant melanoma, Hodgkin's lymphoma, non-Hodgkin's lymphoma and ovarian cancer. The relatively rare occurrence of pregnancy-associated cancer precludes conducting large, prospective studies to examine diagnostic, management and outcome issues. The treatment of pregnancy-associated cancer is complex since it may be associated with adverse fatal effects. In pregnant patients diagnosed with cancer during the first trimester, treatment with multidrug anti-cancer chemotherapy is associated with an increased risk of congenital malformations, spontaneous abortions or fetal death, and therefore, should follow a strong recommendation for pregnancy termination. Second and third trimester exposure is not associated with teratogenic effect but increases the risk of intrauterine growth retardation and low birth weight. There are no sufficient data regarding the teratogenicity of most cytotoxic drugs. Almost all chemotherapeutic agents were found to be teratogenic in animals and for some drugs only experimental data exist. Moreover, no pharmacokinetic studies have been conducted in pregnant women receiving chemotherapy in order to understand whether pregnant women should be treated with different doses of chemotherapy. This article reviews the available data regarding the different aspects of the treatment of cancer during pregnancy.

Haematological cancers in pregnancy

Haematological cancer in pregnancy, although rare, poses a substantial risk to both mother and fetus. Hodgkin's lymphoma is the most common, followed by non-Hodgkin lymphoma and acute leukaemia. Diagnosis of haematological cancers is challenged by an overlap of the disease and gestation-related symptoms and limitations of imaging studies in pregnancy. Data for safety and effectiveness of therapy are scarce and mostly retrospective. This report provides updated guidance for management, focusing on chemotherapy and biological agents. The primary goal of treatment is to preserve the mother's health; hence, pregnancy termination is often advisable at early stages, allowing delivery of adequate therapy. However, at later gestational stages treatment is often feasible. Pregnancy-related hypercoagulability, augmented by cancer, often necessitates thromboprophylaxis. The consequences and complex management of haematological cancer during pregnancy emphasise the need for collaborative research, focusing on basic mechanisms of disease and prospective epidemiological studies.

Effects of chemotherapy during pregnancy on the placenta

Whereas the effects of chemotherapy during pregnancy for mother and fetus are well described, its effects on the placenta remain largely undetermined. We performed a retrospective clinicopathologic analysis of the placenta following chemotherapy. Charts were reviewed for type of malignancy, type and timing of chemotherapy, and fetal and pregnancy outcome. Placentas were studied by standard pathologic analysis as well as computer-assisted morphometry and fluorescence in situ hybridization (FISH) analysis. Patients (n = 13) underwent chemotherapy during pregnancy for carcinoma of breast (3), ovary (2), cervix (2), salivary gland (1), lymphoma/leukemia (4), or rhabdomyosarcoma (1). Eleven patients were treated with DNA-active cytotoxic agents during the 2nd and/or 3rd trimesters; their placentas showed nonspecific findings, including villous hypermaturity, distal villous hypoplasia, villous edema, and excessive extravillous trophoblast, and 4/11 (36%) were small-for-age. In one case (rhabdomyosarcoma), the mother was exposed to cytotoxic agents throughout the entire pregnancy. In this case, associated with severe congenital anomalies, the placenta showed striking nuclear pleomorphism of the extravillous trophoblast of the chorion laeve, associated with FISH-demonstrated hyperpolyploidy. One patient was treated with the targeted tyrosine kinase inhibitor, imatinib, in 2 consecutive pregnancies; these placentas showed no specific anomalies. Our findings suggest that chemotherapy during the 1st trimester induces excessive polyploidization of the chorion laeve trophoblast, likely representing an adaptive response to intraamniotic toxins. Second and 3rd trimester exposure to cytotoxic agents may predispose to placental underdevelopment. However, without appropriate controls (untreated patients with equivalent malignancies), the specific effects of chemotherapy in this group are difficult to assess.

The Role of heat shock protein 27 in extravillous trophoblast differentiation

Trophoblast cells from placental explants differentiate in culture to extravillous trophoblast cells (EVT cells). During trophoblast differentiation heat-shock-protein-27 (HSP27) mRNA and multidrug-resistance-protein-5 (MRP5, transporter of cyclic nucleotides) expression are increased. HSP27 is a regulator of actin filaments structure and dynamic, has a role in cell differentiation and may affect NF-kB activity. In this study we aimed to assess HSP27 level in trophoblast cells and its correlation with motility and differentiation related processes [MMPs activity, nitric oxide (NO), inducible nitric oxide synthase (iNOS), proliferation and MRP5 levels]. We evaluated HSP27 expression in a first trimester human trophoblast explants model designed to assess EVT cells differentiation/migration with/without 6-mercaptopurine (6MP, an EVT inhibitor of migration). We found that HSP27 level is expressed in the nucleous and cytoplasm of non-proliferting villous-trophoblast cells (negative for Ki67) and in the cell periphery and cytoplasm of motile EVT cells. Moreover, 6MP decreased HSP27 nucleous expression that was associated with inhibited MMP2 activity and NO production. Also decreased iNOS expression and increased MRP5 mRNA levels were observed. In conclusion, HSP27 expression is modulated in concordance with migration dependent parameters in trophoblast cells.

How I treat acute and chronic leukemia in pregnancy

The prevalence of pregnancy associated leukemia is approximately 1 case out of 10,000 pregnancies. This rare occurrence precludes the conducting of large, prospective studies to examine diagnostic, management and outcome issues. The treatment of a pregnant woman with leukemia may be associated with severe adverse fetal outcome including death and malformations, and therefore poses a difficult challenge for both the patient and the attending physician. Chemotherapy during the 1st trimester is associated with an increased risk for congenital malformations. However, this risk diminishes as pregnancy advances. When acute leukemia is diagnosed during the 1st trimester, patients should be treated promptly similar to non-pregnant patients. However, the aggressive induction therapy should follow pregnancy termination. When the diagnosis is made later in pregnancy standard chemotherapy regimen should be considered and usually pregnancy termination is not mandatory. However, both the mother and the fetus should be under close observation and delivery should be postponed to a non-cytopenic period. Pregnancy associated chronic myelogenous leukemia (CML) can be treated with interferon throughout pregnancy with no apparent increase in adverse fetal outcome. In the very rare case of chronic lymphocytic leukemia (CLL) during pregnancy treatment can usually be delayed until after delivery.

Impaired migration of trophoblast cells caused by simvastatin is associated with decreased membrane IGF-I receptor, MMP2 activity and HSP27 expression

BACKGROUND

Statins inhibit 3-hydroxy-3-methylglutaryl coenzyme-A reductase, the rate-limiting enzyme of the mevalonate pathway, and are used successfully in the treatment of hypercholesterolaemia. Statins are contraindicated during pregnancy. Lately, we have shown that simvastatin has adverse affects on human first trimester placental explants' proliferation and migration. The objective of the present study was to investigate the molecules involved in mediating simvastatin's effect on trophoblast cell migration. We hypothesized that simvastatin attenuates insuline-like growth factor-I (IGF-I) receptor expression (involved in trophoblast motility), matrix metalloproteinase (MMP) activities, and heat shock protein 27 (HSP27) levels (whose mRNA is actively transcribed during trophoblast differentiation) in trophoblast cells thus consequently effecting their migration.

METHODS

Human placental explants were cultured above a matrigel with/without simvastatin (10 microM) for 5 days. In this model, trophoblast migrates from the villi into the matrigel. Western-blot and immunohistochemistry served for analysing HSP27 expression. Immunohistochemistry was used for assessing IGF-I receptor localization. MMPs activity was assayed by gel zymography.

RESULTS

Simvastatin reduced IGF-I receptor membranal expression, MMP2 activity and HSP27 expression in trophoblast cells (P < 0.05).

CONCLUSIONS

The inhibitory effect of simvastatin on trophoblast cell migration is associated with a significant decrease in the tested molecules, which probably contributes to the impaired migration.