Fetal growth restriction is associated with reduced FasL expression by decidual cells

The regulated cell death at the maternal-fetal interface: beneficial or detrimental?

Regulated cell death (RCD) plays a fundamental role in placental development and tissue homeostasis. Placental development relies upon effective implantation and invasion of the maternal decidua by the trophoblast and an immune tolerant environment maintained by various cells at the maternal-fetal interface. Although cell death in the placenta can affect fetal development and even cause pregnancy-related diseases, accumulating evidence has revealed that several regulated cell death were found at the maternal-fetal interface under physiological or pathological conditions, the exact types of cell death and the precise molecular mechanisms remain elusive. In this review, we summarized the apoptosis, necroptosis and autophagy play both promoting and inhibiting roles in the differentiation, invasion of trophoblast, remodeling of the uterine spiral artery and decidualization, whereas ferroptosis and pyroptosis have adverse effects. RCD serves as a mode of communication between different cells to better maintain the maternal-fetal interface microenvironment. Maintaining the balance of RCD at the maternal-fetal interface is of utmost importance for the development of the placenta, establishment of an immune microenvironment, and prevention of pregnancy disorders. In addition, we also revealed an association between abnormal expression of key molecules in different types of RCD and pregnancy-related diseases, which may yield significant insights into the pathogenesis and treatment of pregnancy-related complications.

Maternal circulating concentrations of soluble Fas and Elabela in early- and late-onset preeclampsia

OBJECTIVE

The Fas/Fas ligand (FASL) system and Elabela-apelin receptor signaling pathways are implicated in the pathophysiology of preeclampsia. The aim of the current study was to investigate whether a model combining the measurement of sFas and Elabela in the maternal circulation may serve as a clinical biomarker for early- and/or late-onset preeclampsia more effectively than measures of each biomarker individually.

METHODS

Blood samples were collected from 214 women in the following groups: (1) normal pregnancy sampled <34 weeks of gestation (n = 56); (2) patients who developed early-onset preeclampsia (n = 54); (3) normal pregnancy sampled ≥34 weeks of gestation (n = 52); (4) patients who developed late-onset preeclampsia (n = 52). Maternal circulating soluble Fas and Elabela concentrations were determined using sensitive and validated immunoassays. Two sample t-tests, multivariate logistic regression, and receiver operating characteristic curves were used for analyses.

RESULTS

(1) Women with early-onset preeclampsia, and those with late-onset preeclampsia with placental lesions of maternal vascular malperfusion, had increased concentrations of sFas compared to their gestational age-matched normal controls; (2) women with late-onset preeclampsia, but not those with early-onset preeclampsia, had increased concentrations of Elabela compared to their gestational age-matched counterparts; and (3) an increase in both Elabela and sFas concentrations was more strongly associated with late-onset preeclampsia than early-onset preeclampsia relative to models including either of the markers alone.

CONCLUSIONS

A combined model of maternal sFas and Elabela concentrations provides a stronger association with late-onset preeclampsia than either protein alone. This finding demonstrates the possibility to improve the classification of late-onset preeclampsia by combining the results of both molecular biomarkers.

Perfluorooctanoic acid exposure in early pregnancy induces oxidative stress in mice uterus and liver

This study aimed to explore the mechanism of perfluorooctanoic acid (PFOA) toxicity on the uterus and liver of mice during early pregnancy. Pregnant mice were given 0, 1, 5, 10, 20, and 40 mg/kg PFOA daily by gavage from gestational day (GD) 1-7 and sacrificed on GD 9. Subsequently, several toxicity parameters were evaluated, including the uterus and liver weights, liver and uterine indexes, histopathological changes of the liver and uterus, and levels of malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in the liver. We also determined the expressions of FAS, FASL, Bax, Bcl-2, and Caspase-3 in decidual cells by immunohistochemistry and the TUNEL assay to detect apoptosis uterine cells. The results showed that PFOA increased the liver weights and reduced the uterus index in a dose-dependent manner. With increasing doses of PFOA, the levels of SOD and GSH-Px were significantly decreased, and MDA increased substantially in liver tissue. 20 mg/kg and 40 mg/kg of PFOA caused more substantial harm to the uterus, thus a higher probability for congestion and resorption. The expression of FAS, FASL, Bax, and Caspase-3 in decidual cells of the uterus in the PFOA treatment groups significantly increased in a dose-dependent manner. The expression of Bcl-2 was downregulated, decreasing the Bcl-2/Bax ratio. At gestation day 9, the control group had significantly fewer apoptotic cells in the uterus and shallower staining than the 40 mg/kg PFOA group. The findings of this study suggest that oxidative damage may be one of the mechanisms by which PFOA induces liver toxicity, and a subsequent increase in uterine cell apoptosis may cause embryo loss or damage.

Allogenic Use of Human Placenta-Derived Stromal Cells as a Highly Active Subtype of Mesenchymal Stromal Cells for Cell-Based Therapies

The application of mesenchymal stromal cells (MSCs) from different sources, including bone marrow (BM, bmMSCs), adipose tissue (atMSCs), and human term placenta (hPSCs) has been proposed for various clinical purposes. Accumulated evidence suggests that the activity of the different MSCs is indirect and associated with paracrine release of pro-regenerative and anti-inflammatory factors. A major limitation of bmMSCs-based treatment for autologous application is the limited yield of cells harvested from BM and the invasiveness of the procedure. Similar effects of autologous and allogeneic MSCs isolated from various other tissues were reported. The easily available fresh human placenta seems to represent a preferred source for harvesting abundant numbers of human hPSCs for allogenic use. Cells derived from the neonate tissues of the placenta (f-hPSC) can undergo extended expansion with a low risk of senescence. The low expression of HLA class I and II on f-hPSCs reduces the risk of rejection in allogeneic or xenogeneic applications in normal immunocompetent hosts. The main advantage of hPSCs-based therapies seems to lie in the secretion of a wide range of pro-regenerative and anti-inflammatory factors. This renders hPSCs as a very competent cell for therapy in humans or animal models. This review summarizes the therapeutic potential of allogeneic applications of f-hPSCs, with reference to their indirect pro-regenerative and anti-inflammatory effects and discusses clinical feasibility studies.

Serum levels of soluble Fas and Fas ligand in pregnant women who smoke

PROBLEM

Cigarette smoking during pregnancy is associated with reduced incidence of preeclampsia. Mechanisms of this association are poorly understood. Cytokines, angiogenic, and anti-angiogenic factors are involved in the pathogenesis of preeclampsia. During normal pregnancy, Fas ligand (FasL) present on trophoblasts induces apoptosis of Fas bearing maternal immune cells. In preeclampsia, trophoblasts show increased apoptosis with reduced expression of FasL. We determined serum levels of cytokines, angiogenic (placental growth factor), anti-angiogenic factors (soluble endoglin, soluble fms-like tyrosine kinase-1), soluble Fas (sFas), and soluble FasL (sFasL) in smoking and non-smoking pregnant women.

METHODS

Using enzyme-linked immunosorbent and multiplex assays, we prospectively analyzed serum levels of angiogenic, anti-angiogenic factors, cytokines, sFas and sFasL in normotensive smoking and non-smoking mothers. Exclusion criteria included maternal hypertension, auto-immune disorders, rupture of membranes, evidence of labor, and drug use.

RESULTS

Of 100 women recruited to the study, 51 were in the non-smoking and 49 in the smoking group. Except for lower maternal age in the smoking group, there was no difference in gestation, BMI, gravidity, or ethnicity between the two groups. Levels of angiogenic, anti-angiogenic factors, cytokines, and sFas were similar between the two groups but sFasL levels were significantly higher in smoking group (38 pg/ml vs. 16 pg/ml, p < .001) and remained significant after controlling for confounders.

CONCLUSION

Our study demonstrates higher sFasL levels in pregnant women who smoke. Higher sFasL may explain the reduced incidence of preeclampsia in pregnant mothers who smoke by inducing apoptosis of immune cells which may otherwise induce trophoblast apoptosis.

Innate Lymphoid Cells at the Maternal-Fetal Interface in Human Pregnancy

Pregnancy constitutes a major challenge to the maternal immune system, which must tolerate fetal alloantigen encoded by paternal genes. In addition to their role in inducing maternal-fetal immune tolerance, accumulating evidence indicates that decidual immune cells are involved in several processes required for a successful pregnancy, including trophoblast invasion as well as tissue and spiral artery remodeling. Innate lymphoid cells (ILCs), an important branch of the innate immune system, which has expanded rapidly in recent years, are strong actors in mucosal immunity, tissue homeostasis and metabolism regulation. With the recent identification of ILCs in the human decidua, the role of ILCs at the maternal-fetal interface raises concern. Herein, we review the presence and characterization of ILCs in the human decidua, as well as their function in normal pregnancy and pathological pregnancy, including reproductive failure, preeclampsia and others.

Analysis of hyaluronic acid in the endometrium of women with polycystic ovary syndrome

Endometrium extracellular matrix provides a wide range of signals at different cellular levels, like cell death and proliferation, which can be important for regulating menses and reducing the proliferative processes. The objective of this study is to evaluate hyaluronic acid concentration, the enzymes of hyaluronic acid synthases in the endometrium of patients with polycystic ovary syndrome (PCOS) and eumenorrheic women. A total of 60 endometrial samples from 30 patients with PCOS and 30 women with regular menstrual cycles in the proliferative phase, attended at Gynecology Division of Clinical Hospital of the FMUSP (HC-USP). Profile determination and the concentration of hyaluronic acid was performed by the biochemical method of the fluorimetric assay (ELISA-like). Its location in the endometrial tissue as well as the dosage of enzymes synthases (HAS1, HAS2 and HAS3) was done by immunohistochemistry and western blotting. Statistical analyses were performed with one-way ANOVA, followed by the Bonferroni test. Regarding hyaluronic acid synthases, there was a higher HAS1 and HAS2 reactivity and lower HAS3 reactivity in the PCOS endometrium compared to women with regular menstrual cycles in the proliferative phase. We suggest that PCOS patients have different composition of hyaluronic acid in relation to a regular cycle in the proliferative phase.

Fetal gender specific expression of tandem-repeat galectins in placental tissue from normally progressed human pregnancies and intrauterine growth restriction (IUGR)

INTRODUCTION

The tandem-repeat type galectins, which comprise of gal-4, -6, -8, -9, and -12, form a sub-family of galectins. Gal-6 is expressed only in rodents, whereas the other four galectins, tandem-repeat galectins, are also detectable in human tissue. The placental expression of individual members of the tandem-repeat gal family is increasingly known, however, systematic, comparative analysis especially in the human placenta from normal or pathological pregnancies is still lacking.

MATERIAL AND METHODS

Within this study, third trimester placentas obtained at delivery (n = 14 IUGR, n = 15 controls, equally divided in placentas from male and female fetuses) were analyzed for the expression of gal-4, -8, -9 and -12 by immunohistology and immunofluorescence, data were obtained by using a semiquantitative scoring system. Double immune-fluorescence with trophoblast specific markers was used to identify co-expression in the decidua.

RESULTS

We identified dysregulation of tandem repeat galectins in IUGR placentas with a strong connection to the fetal gender. We identified a significantly lower expression of gal-4 and gal-9 in villous trophoblast tissue of IUGR placentas with male fetuses and a downregulation of gal-4 and gal-8 in extravillous trophoblast (EVT) from IUGR and male fetuses. Conversely, expression of gal-9 and gal-12 was higher in EVT of IUGR cases in placentas with female fetuses. Double immunofluorescence using cytokeratin-7 confirmed the expression of tandem-repeat galectins in EVT.

DISCUSSION AND CONCLUSION

The human placenta expresses tandem-repeat type galectins in villous trophoblasts, EVT, endothelial cells and decidual stromal cells. Summarizing all effects, there is significant down-regulation of gal-4, -8 and gal-9 in the IUGR trophoblast of male fetuses. In contrast, in IUGR pregnancies with female fetus gal-9 and gal-12 are upregulated in the EVT and in endothelial cells in the cases of gal-12. Therefore we propose a fetal-gender specific action of tandem repeat galectins in IUGR placentas.

Fas and FasL expression in placentas complicated with intrauterine growth retardation with and without preeclampsia

OBJECTIVE

To compare the level of Fas and FasL immunohistochemical expression in villous trophoblast (VT), extravillous trophoblast (EVT) cells, decidual cells (DC), endothelial cells (EC) of villous blood vessels and spiral arteries between the study groups of intrauterine growth retardation (IUGR) placentas with and without preeclampsia (PE).

METHODS

The study included 17 placentas from pregnancies complicated by IUGR + PE and 17 placentas from pregnancies complicated by idiopathic IUGR (I-IUGR). Seventeen placentas from normal pregnancies served as a control group. CD31 was used to detect endothelial cells (EC). Immunohistochemical expression of Fas and FasL was assessed in all examined parts of placenta using the semi-quantitative HSCORE method.

RESULTS

FasL expression was significantly higher in all examined parts of placenta in I-IUGR as compared to IUGR + PE and control group. Placentas with IUGR + PE had the significantly lowest expression of FasL in VT and EC of villi vessels. Expression of Fas did not differ significantly between the study groups.

CONCLUSION

Different expression of FasL in placentas from I-IUGR and IUGR + PE suggests that FasL probably has a different role in the etiology of these two syndromes.

Increased plasma levels of CK-18 as potential cell death biomarker in patients with HELLP syndrome

HELLP (hemolysis, elevated liver enzymes, low platelets) syndrome represents a life-threatening pregnancy disorder with high fetal and maternal mortality, but its underlying molecular mechanisms remain unknown. Although apoptosis has been implicated in HELLP syndrome, its pathogenic role remains largely unclear. In the present study, we investigated whether the detection of apoptosis by novel plasma biomarkers is of diagnostic value in HELLP patients. For this purpose, we analyzed two biomarkers that specifically detect apoptosis or overall cell death of epithelial cells, such as hepatocytes or placental trophoblasts, through the release of caspase-cleaved or total (caspase-cleaved and uncleaved) cytokeratin-18 (CK-18) in plasma of HELLP patients compared with pregnant as well as non-pregnant healthy women. In addition, caspase activation and cell death were determined in placental tissues of HELLP patients and individuals with normal pregnancy. In contrast to pregnant or non-pregnant healthy controls, we observed significantly increased levels of both caspase-cleaved and total CK-18 in plasma of HELLP patients. Following delivery, CK-18 levels rapidly decreased in HELLP patients. Caspase activation and cell death were also elevated in placental tissues from HELLP patients compared with healthy pregnant women. These data demonstrate not only that apoptosis is increased in HELLP syndrome, but also that caspase-cleaved or total CK-18 are promising plasma biomarkers to identify patients with HELLP syndrome. Thus, further studies are warranted to evaluate the utility of these biomarkers for monitoring disease activity in HELLP syndrome.

FAS and FAS-L genotype and expression in patients with recurrent pregnancy loss

We assessed FAS and FAS-L gene polymorphisms and messenger RNA (mRNA) levels in patients with recurrent pregnancy loss (RPL). This case-control study compared 129 women with RPL with 235 healthy multiparous women (control group). Genomic DNA and total mRNA were extracted from whole blood, and polymorphisms genotyping was performed by polymerase chain reaction (PCR). Messenger RNA expression levels were analyzed by real-time PCR. Data were analyzed by chi-square and Fisher exact tests; P < .05 was considered significant. There were no significant differences in the FAS (670 A/G) genotype or allelic frequencies between the RPL and control groups. We found significant differences in the FAS-L (844 C/T) genotype and allelic frequencies between women with RPL and controls. Patients with RPL had significantly higher FAS-L expression. Our data suggest that FAS-L gene polymorphism is associated with increased susceptibility to RPL. Moreover, women with RPL seem to abnormally express FAS-FAS-L molecules.

Evaluation of FAS and caspase-3 in the endometrial tissue of patients with idiopathic infertility and recurrent pregnancy loss

OBJECTIVE

To investigate expression of BcL-2, FAS, FAS ligand (FASL) and cleaved caspase-3 in the endometrial tissue of women with idiopathic infertility (with two consecutive failed cycles of in vitro fertilization) and women with idiopathic recurrent pregnancy loss. The control group consisted of fertile women.

STUDY DESIGN

Endometrial tissue samples from fertile women (n=25), women with idiopathic infertility (n=25) and women with idiopathic recurrent pregnancy loss (n=25) were collected on the seventh or eighth postovulatory day of their menstrual cycles for evaluation. Expression of BcL-2, FAS, FASL and cleaved caspase-3 was assessed using immunohistochemical methods.

RESULTS

Expression of BcL-2 and FAS was significantly higher and lower, respectively, in the women with idiopathic infertility than in the other groups (p<0.01). Expression of cleaved caspase-3 was significantly lower in the women with idiopathic infertility than in the other groups (p<0.01). Expression of FASL was similar in all three groups.

CONCLUSION

Disturbances in endometrial apoptosis may be a contributing factor in patients with idiopathic infertility and recurrent pregnancy loss.

A balancing act: mechanisms by which the fetus avoids rejection by the maternal immune system

Successful pregnancy requires strict temporal regulation of maternal immune function to accommodate the growing fetus. Early implantation is facilitated by inflammatory processes that ensure adequate vascular remodeling and placental invasion. To prevent rejection of the fetus, this inflammation must be curtailed; reproductive immunologists are discovering that this process is orchestrated by the fetal unit and, in particular, the extravillous trophoblast. Soluble and particulate factors produced by the trophoblast regulate maternal immune cells within the decidua, as well as in the periphery. The aim of this review is to discuss the action of recently discovered immunomodulatory factors and mechanisms, and the potential effects of dysregulation of such mechanisms on the maternal immune response that may result in pregnancy loss or preeclampsia.

Apoptosis, proliferation and Fas ligand expression in placental trophoblast from pregnancies complicated by HELLP syndrome or pre-eclampsia

OBJECTIVE

To investigate apoptosis, proliferation and Fas ligand expression of placental trophoblast in the hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome and in pre-eclampsia (PE), and to compare this with normal pregnancies.

DESIGN

Prospective study.

SETTING

University hospital in Croatia.

SAMPLE

Placentae from women with HELLP syndrome (n=10), PE (n=10) and normal pregnancies (n=10).

METHODS

The HELLP syndrome was diagnosed with platelets <100×10(9) /L, aspartate aminotransferase (AST) and alanine transaminase (ALT) >70 U/L and lactic acid dehydrogenase (LDH) > 600 U/L. Pre-eclampsia was diagnosed at blood pressure >140/90 mmHg, with proteinuria >300 mg/L/24 hours. For detection of apoptosis and proliferation in villous trophoblast, antibodies M30 and Ki-67 were used. Expression of Fas ligand was assessed using immunohistochemistry and the semiquantitative HSCORE method.

MAIN OUTCOME MEASURES

Apoptosis, proliferation and Fas ligand expression in villous trophoblast.

RESULTS

Apoptosis, proliferation and Fas ligand expression were higher in villous trophoblast in HELLP syndrome than in the PE group (p=0.015, p=0.018 and p=0.002, respectively) and the control group (p=0.000, p=0.012 and p=0.049, respectively). Placentae from the PE group had higher levels of apoptosis (p=0.019), lower Fas ligand expression (p=0.029) and no difference in proliferation (p=0.887) compared with the control group.

CONCLUSIONS

There is an increase in apoptosis, proliferation and Fas ligand expression in placentae from women with HELLP syndrome compared with placentae from PE and normal pregnancies. Our findings indicate the possibility of differential mechanisms behind HELLP syndrome and PE.

Early-pregnancy soluble Fas levels in idiopathic small-for-gestational-age pregnancies

OBJECTIVE

We sought to determine first- and second-trimester serum soluble Fas (sFas) and placental growth factor (PlGF) levels in idiopathic small-for-gestational-age (SGA) pregnancies.

STUDY DESIGN

We measured sFas and PlGF levels in women who delivered SGA infants uncomplicated by preeclampsia and in control subjects. For sFas there were 34 cases and 318 control subjects in the first trimester and 9 cases and 11 control subjects in the second trimester. For PlGF there were 31 cases and 281 control subjects in the first trimester and 8 cases and 11 control subjects in the second trimester.

RESULTS

SGA pregnancies had lower sFas levels than control subjects in the second trimester (3703 + or - 209 pg/mL vs 4562 + or - 241 pg/mL; P = .015), but not in the first trimester (4892 + or - 191 pg/mL vs 4971 + or - 177 pg/mL; P = .68). There was no difference in PlGF levels between SGA and normal pregnancies in both trimesters.

CONCLUSION

Serum sFas levels were lower in idiopathic SGA pregnancies in the second trimester, but not in the first. There was no difference in serum PlGF levels in either trimester.

The mother's immune system is a balanced threat to the foetus, turning to protection of the neonate

Immunological tolerance by the mother prevents rejection of the foetus, but aberrations may increase risk of abnormalities like spontaneous abortion, or foetal growth restriction. The neonate is normally colonized with mother's gut microflora, mainly composed of protective anaerobes. This least threatening form of microbial colonization of the neonate, is impaired by sectio delivery, but supported by breastfeeding. Mother's transplacental IgG, secretory IgA and other milk components help protect the neonate together with its own slowly expanding immune system.

CONCLUSION

The mother's immune system tolerates her foetus via several mechanisms. Failure to do so may cause foetal growth retardation, or spontaneous abortion. The mother and the neonate cooperate in preventing infections in the offspring.

Immune function in pregnancy: the role of corticotropin-releasing hormone

Pregnancy represents a major challenge to the maternal immune system since it has to tolerate the semi-allograft fetus. Indeed, the success of pregnancy requires an appropriate immunological interaction between the mother and the fetus. Furthermore, evidence suggests that some pregnancy complications, such as spontaneous abortions, preeclampsia and intrauterine growth restriction, are associated with abnormal maternal-fetal immune responses. Corticotropin-releasing hormone (CRH), a 41-amino acid peptide originally found in the hypothalamus, appears to have a fundamental role in the mechanisms responsible for the implantation and maintenance of human pregnancy. Reproductive CRH is a form of tissue CRH (CRH found in peripheral tissues), analogous to the immune CRH detected in peripheral inflammatory sites. Reproductive CRH has been identified in the endometrial glands, the decidualized endometrial stroma and the placental trophoblast, synctiotrophoblast and decidua. Reproductive CRH participates in various reproductive functions with an inflammatory component, where it serves as an autocrine/paracrine modulator. The immunological mechanisms contributing to the establishment and maintenance of pregnancy are not fully understood. The present article focuses on the potential roles of CRH on the physiology and pathophysiology of pregnancy and highlights its participation in implantation, early fetal immunotolerance and parturition.