Role of microparticles in recurrent miscarriages and other adverse pregnancies: a review

Impact of acute moderate-intensity aerobic exercise on circulating extracellular vesicles in pregnant and non-pregnant women

Exercise improves cardiovascular and metabolic health in pregnancy and may represent a non-pharmacological approach to improving pregnancy outcomes. Extracellular vesicles (EVs) are emerging biomarkers of endothelial dysfunction and offer the potential for evaluating vascular health non-invasively during pregnancy. The purpose of this study was to investigate changes in circulating EV levels after an acute bout of moderate-intensity aerobic exercise in healthy pregnant and non-pregnant women. We studied plasma samples from pregnant (N = 13, 13-28 weeks) and non-pregnant (N = 17) women. A pre-exercise blood sample was obtained followed by a 30 min bout of moderate-intensity treadmill-based exercise. Immediately following the exercise, a post-exercise blood draw was collected. Large EVs were isolated from plasma by differential centrifugation and characterized by Western blot and electron microscopy. We quantified circulating EVs by nanoscale flow cytometry. Endothelial EVs were identified as VE-Cadherin+, platelet EVs as CD41+, and leukocyte EVs as CD45+ events. Acute exercise was associated with a significant reduction in levels of circulating endothelial EVs in the non-pregnant group (p = 0.0232) but not in the pregnant group (p = 0.2734). A greater proportion of non-pregnant women (13/17, 76.47%) exhibited a reduction in endothelial EVs compared with their pregnant counterparts (4/13, 30.76%, p < 0.05). We also observed a positive association between measures of fitness (average speed) and baseline levels of platelet (r = 0.5816, p = 0.0159) and total EVs (r = 0.5325, p = 0.0296) in the non-pregnant group but not in pregnant individuals. Collectively, our study highlights that after a matched acute exercise, changes to circulating EV levels differ depending on pregnancy status.

Long Non-Coding RNA ZEB2-AS1 Augments Activity of Trophoblast Cells and Prevents the Development of Recurrent Spontaneous Abortion in Mice Through EZH2-Mediated CST3 Inhibition

Recurrent spontaneous abortion (RSA) is the most common complication of pregnancy where reduced invasion of trophoblasts plays a major role. This work aimed to explore the effect of abnormally expressed long non-coding RNA (lncRNA) ZEB2-AS1 on the occurrence of RSA. Differentially expressed lncRNAs in trophoblast cells between healthy controls and patients with RSA were screened using the GEO database. Female CBA/J mice were allowed to mate with male DBA/2 mice to establish inbred mice with RSA. ZEB2-AS1 was poorly expressed in placental tissues and trophoblast cells in the condition of RSA. ZEB2-AS1 upregulation augmented proliferation, migration, and invasion of trophoblast cells in vitro. ZEB2-AS1 negatively regulated cystatin C (CST3) expression. Further overexpression of CST3 blocked the activity of trophoblast cells. ZEB2-AS1 recruited enhancer of EZH2 to the promoter region of CST3, which increased H3K27me3 modification to suppress CST3 expression. In vivo, overexpression of ZEB2-AS1 reduced embryo resorption rate and increased the weights of fetuses and placentas in mice with RSA. However, the protective roles of ZEB2-AS1 were blocked upon artificial silencing of EZH2 or upregulation of CST3. Taken together, this study demonstrates that ZEB2-AS1 enhances activity of trophoblast cells and prevents RSA development through reducing CST3 expression in an EZH2-dependent manner.

Extracellular Vesicles and Antiphospholipid Syndrome: State-of-the-Art and Future Challenges

Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by thromboembolism, obstetric complications, and the presence of antiphospholipid antibodies (aPL). Extracellular vesicles (EVs) play a key role in intercellular communication and connectivity and are known to be involved in endothelial and vascular pathologies. Despite well-characterized in vitro and in vivo models of APS pathology, the field of EVs remains largely unexplored. This review recapitulates recent findings on the role of EVs in APS, focusing on their contribution to endothelial dysfunction. Several studies have found that APS patients with a history of thrombotic events have increased levels of EVs, particularly of endothelial origin. In obstetric APS, research on plasma levels of EVs is limited, but it appears that levels of EVs are increased. In general, there is evidence that EVs activate endothelial cells, exhibit proinflammatory and procoagulant effects, interact directly with cell receptors, and transfer biological material. Future studies on EVs in APS may provide new insights into APS pathology and reveal their potential as biomarkers to identify patients at increased risk.

NLRP3 inflammasome as the potential target mechanism and therapy in recurrent spontaneous abortions

Recurrent spontaneous abortions (RSA) are defined as aborting three or more times within 20 gestational weeks with the same sexual partner. The occurrence of RSA exhibits an upward trend in modern society. The NACHT, LRR and PYD domains‑containing protein 3 (NLRP3) inflammasome, which is an important component of innate immunity, serves a role in the immune response and in disease occurrence. In the present study, it was demonstrated that the disordered regulation of the NLRP3 inflammasome may induce the occurrence of RSA. The results of the present study demonstrated that caspase‑1 activity, interleukin (IL)‑1β and IL‑18 were upregulated in patients with RSA compared with healthy controls. Further investigation was performed to elucidate the mechanism of activation of the NLRP3 inflammasome in patients with RSA. The inhibition of the NLRP3 inflammasome in a RSA mouse model was able to decrease the rate of abortions. Finally, the present study demonstrated that the activated NLRP3 inflammasome was involved in the pathogenesis of RSA through regulation of the Th17 and regulatory T cell imbalance. The present study provides a potential future therapeutic target for RSA via the NLRP3 inflammasome.

Increased circulating cell-derived microparticle count is associated with recurrent implantation failure after IVF and embryo transfer

Cell-derived microparticles (cMPs) are small membrane vesicles that are released from many different cell types in response to cellular activation or apoptosis. Elevated cMP counts have been found in almost all thrombotic diseases and pregnancy wastage, such as recurrent spontaneous abortion and in a number of conditions associated with inflammation, cellular activation and angiogenesis. cMP count was investigated in patients experiencing unexplained recurrent implantation failure (RIF). The study group was composed of 30 women diagnosed with RIF (RIF group). The first control group (IVF group) (n = 30) comprised patients undergoing a first successful IVF cycle. The second control group (FER group) included 30 healthy women who had at least one child born at term and no history of infertility or obstetric complications. cMP count was significantly higher in the RIF group compared with the IVF and FER groups (P < 0.05 and P < 0.01, respectively) (RIF group: 15.8 ± 6.2 nM phosphatidylserine equivalent [PS eq]; IVF group: 10.9 ± 5.3 nM PS eq; FER group: 9.6 ± 4.0 nM PS eq). No statistical difference was found in cMP count between the IVF and FER groups. Increased cMP count is, therefore, associated with RIF after IVF and embryo transfer.

Higher levels of procoagulant microparticles in women with recurrent miscarriage are not associated with antiphospholipid antibodies

STUDY QUESTION

Are the levels of circulating cell-derived microparticles (cMPs) in patients with recurrent miscarriage (RM) associated with the antiphospholipid syndrome (APS)?

SUMMARY ANSWER

cMPs in women with RM are not associated with antiphospholipid antibodies (aPLs).

WHAT IS KNOWN ALREADY

Previous studies have focused on cMP levels in RM patients. Most studies have shown higher levels of cMPs in RM patients whereas others have reported lower levels. Data regarding cMPs in patients with the APS are scanty in the literature.

STUDY DESIGN, SIZE, DURATION

A case-control study including three groups of patients. A total of 154 women were prospectively recruited from September 2009 to October 2013. Four patients refused to participate. The APS group consisted of 50 women that had been previously diagnosed with primary APS and had had ≥3 consecutive first trimester miscarriages. The uRM group included 52 couples with ≥3 consecutive first trimester miscarriages of unknown etiology. The fertile control (FER) group was composed of 52 healthy fertile women with no history of pregnancy losses. Miscarriage was defined as intrauterine pregnancy loss at <10 weeks' size on ultrasound.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Venous blood samples for coagulation studies and cMP determinations were obtained. All patients underwent a thrombophilia study.

MAIN RESULTS AND THE ROLE OF CHANCE

cMP levels were significantly higher in the APS and uRM groups versus the FER group (P < 0.0001 and P = 0.009, respectively) (cMP number × 10(3)/ml plasma [mean ± SD]: APS: 18.5 ± 13.6; uRM: 16.3 ± 13.8; FER: 9.7 ± 4.6). There were no statistically significant differences in cMP levels between the APS and uRM groups.

LIMITATIONS, REASONS FOR CAUTION

The sample size was arbitrarily decided according to previous studies analyzing cMPs in RM patients. Different cMP subtypes were not investigated.

WIDER IMPLICATIONS OF THE FINDINGS

The present study adds further data on the subject showing that patients with RM, irrespective of testing positive for aPLs, have increased levels of cMPs compared with healthy fertile controls. The presence of elevated cMPs in RM women may reflect an ongoing systemic pathological, albeit asymptomatic, status that can become deleterious in the setting of pregnancy.

STUDY FUNDING/COMPETING INTERESTS

This study was supported in part by grant from FIS-PI11/01560 within the 'Plan Nacional de I+D+I' and co-funded by the 'ISCIII-Subdirección General de Evaluación' and the 'Fondo Europeo de Desarrollo Regional (FEDER)'. The authors have no competing interests to disclose.

TRIAL REGISTRATION NUMBER

Not applicable.

Evaluation of current and new biomarkers in severe preeclampsia: a microarray approach reveals the VSIG4 gene as a potential blood biomarker

Preeclampsia is a placental disease characterized by hypertension and proteinuria in pregnant women, and it is associated with a high maternal and neonatal morbidity. However, circulating biomarkers that are able to predict the prognosis of preeclampsia are lacking. Thirty-eight women were included in the current study. They consisted of 19 patients with preeclampsia (13 with severe preeclampsia and 6 with non-severe preeclampsia) and 19 gestational age-matched women with normal pregnancies as controls. We measured circulating factors that are associated with the coagulation pathway (including fibrinogen, fibronectin, factor VIII, antithrombin, protein S and protein C), endothelial activation (such as soluble endoglin and CD146), and the release of total and platelet-derived microparticles. These markers enabled us to discriminate the preeclampsia condition from a normal pregnancy but were not sufficient to distinguish severe from non-severe preeclampsia. We then used a microarray to study the transcriptional signature of blood samples. Preeclampsia patients exhibited a specific transcriptional program distinct from that of the control group of women. Interestingly, we also identified a severity-related transcriptional signature. Functional annotation of the upmodulated signature in severe preeclampsia highlighted two main functions related to “ribosome” and “complement”. Finally, we identified 8 genes that were specifically upmodulated in severe preeclampsia compared with non-severe preeclampsia and the normotensive controls. Among these genes, we identified VSIG4 as a potential diagnostic marker of severe preeclampsia. The determination of this gene may improve the prognostic assessment of severe preeclampsia.