Umbilical Cord Blood Circulating Progenitor Cells and Endothelial Colony-Forming Cells Are Decreased in Preeclampsia

Neonatal outcomes of preterm infants with pulmonary hypertension: clustering based on prenatal risk factors

BACKGROUND

To investigate association of prenatal risk factors and neonatal outcomes of preterm infants with pulmonary hypertension (PH).

METHODS

A prospective cohort study of very-low-birth-weight infants born at 22-29 weeks' gestation who received PH-specific treatment during hospitalization. Infants were classified using a two-step cluster analysis based on gestational age (GA), small-for-gestational-age (SGA), exposure to antenatal corticosteroids (ACS), histologic chorioamnionitis (HCA), and oligohydramnios.

RESULTS

Among 910 infants, six clusters were identified: cluster A (HCA, n = 240), cluster B (oligohydramnios, n = 79), cluster C (SGA, n = 74), cluster D (no-ACS, n = 109), cluster E (no dominant parameter, n = 287), and cluster F (HCA and oligohydroamnios, n = 121). Cluster A was used as a reference group for comparisons among clusters. Compared to cluster A, cluster C (aHR: 1.63 [95% CI: 1.17-2.26]) had higher risk of overall in-hospital mortality. Clusters B (aHR: 1.52 [95% CI: 1.09-2.11]), D (aHR: 1.71 [95% CI: 1.28-2.30]), and F (aHR: 1.51 [95% CI: 1.12-2.03]) had higher risks of receiving PH-specific treatment within the first week of birth compared to cluster A.

CONCLUSION

These findings may provide a better understanding of prenatal risk factors contributing to the development of PH.

IMPACT

Pulmonary hypertension (PH), presenting as hypoxic respiratory failure, has complex etiologies in preterm infants. Although multifactorial risks for the development of PH in preterm infants are known, few studies have classified infants with similar etiologies for PH. Each cluster has distinct patterns of prenatal condition and neonatal outcome.

The vascular phenotype of BPD: new basic science insights-new precision medicine approaches

Bronchopulmonary dysplasia (BPD) is the most common complication of preterm birth. Up to 1/3 of children with BPD develop pulmonary hypertension (PH). PH increases mortality, the risk of adverse neurodevelopmental outcome and lacks effective treatment. Current vasodilator therapies address symptoms, but not the underlying arrested vascular development. Recent insights into placental biology and novel technological advances enabling the study of normal and impaired lung development at the single cell level support the concept of a vascular phenotype of BPD. Dysregulation of growth factor pathways results in depletion and dysfunction of putative distal pulmonary endothelial progenitor cells including Cap1, Cap2, and endothelial colony-forming cells (ECFCs), a subset of vascular progenitor cells with self-renewal and de novo angiogenic capacity. Preclinical data demonstrate effectiveness of ECFCs and ECFC-derived particles including extracellular vesicles (EVs) in promoting lung vascular growth and reversing PH, but the mechanism is unknown. The lack of engraftment suggests a paracrine mode of action mediated by EVs that contain miRNA. Aberrant miRNA signaling contributes to arrested pulmonary vascular development, hence using EV- and miRNA-based therapies is a promising strategy to prevent the development of BPD-PH. More needs to be learned about disrupted pathways, timing of intervention, and mode of delivery. IMPACT: Single-cell RNA sequencing studies provide new in-depth view of developmental endothelial depletion underlying BPD-PH. Aberrant miRNA expression is a major cause of arrested pulmonary development. EV- and miRNA-based therapies are very promising therapeutic strategies to improve prognosis in BPD-PH.

Enhancing endothelial colony-forming cells for treating diabetic vascular complications: challenges and clinical prospects

Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia, leading to various vascular complications. Accumulating evidence indicates that endothelial colony-forming cells (ECFCs) have attractive prospects for repairing and restoring blood vessels. Thus, ECFCs may be a novel therapeutic option for diabetic patients with vascular complications who require revascularization therapy. However, it has been reported that the function of ECFCs is impaired in DM, which poses challenges for the autologous transplantation of ECFCs. In this review, we summarize the molecular mechanisms that may be responsible for ECFC dysfunction and discuss potential strategies for improving the therapeutic efficacy of ECFCs derived from patients with DM. Finally, we discuss barriers to the use of ECFCs in human studies in light of the fact that there are no published reports using these cells in humans.

Human Cord Blood Endothelial Progenitor Cells and Pregnancy Complications (Preeclampsia, Gestational Diabetes Mellitus, and Fetal Growth Restriction)

Hemangioblasts give rise to endothelial progenitor cells (EPCs), which also express the cell surface markers CD133 and c-kit. They may differentiate into the outgrowth endothelial cells (OECs) that control neovascularization in the developing embryo. According to numerous studies, reduced levels of EPCs in circulation have been linked to human cardiovascular disorders. Furthermore, preeclampsia and senescence have been linked to levels of EPCs produced from cord blood. Uncertainties surround how preeclampsia affects the way EPCs function. It is reasonable to speculate that preeclampsia may have an impact on the function of fetal EPCs during the in utero period; however, the present literature suggests that maternal vasculopathies, including preeclampsia, damage fetal circulation. Additionally, the differentiation potential and general activity of EPCs may serve as an indicator of the health of the fetal vascular system as they promote neovascularization and repair during pregnancy. Thus, the purpose of this review is to compare-through the assessment of their quantity, differentiation potency, angiogenic activity, and senescence-the angiogenic function of fetal EPCs obtained from cord blood for normal and pregnancy problems (preeclampsia, gestational diabetes mellitus, and fetal growth restriction). This will shed light on the relationship between the angiogenic function of fetal EPCs and pregnancy complications, which could have an effect on the management of long-term health issues like metabolic and cardiovascular disorders in offspring with abnormal vasculature development.

Recent advances in endothelial colony-forming cells: from the transcriptomic perspective

Endothelial colony-forming cells (ECFCs) are progenitors of endothelial cells with significant proliferative and angiogenic ability. ECFCs are a promising treatment option for various diseases, such as ischemic heart disease and peripheral artery disease. However, some barriers hinder the clinical application of ECFC therapeutics. One of the current obstacles is that ECFCs are dysfunctional due to the underlying disease states. ECFCs exhibit dysfunctional phenotypes in pathologic states, which include but are not limited to the following: premature neonates and pregnancy-related diseases, diabetes mellitus, cancers, haematological system diseases, hypoxia, pulmonary arterial hypertension, coronary artery diseases, and other vascular diseases. Besides, ECFCs are heterogeneous among donors, tissue sources, and within cell subpopulations. Therefore, it is important to elucidate the underlying mechanisms of ECFC dysfunction and characterize their heterogeneity to enable clinical application. In this review, we summarize the current and potential application of transcriptomic analysis in the field of ECFC biology. Transcriptomic analysis is a powerful tool for exploring the key molecules and pathways involved in health and disease and can be used to characterize ECFC heterogeneity.

Fetal endothelial colony-forming cells: Possible targets for prevention of the fetal origins of adult diseases

Endothelial colony-forming cells (ECFCs), a subset of circulating and resident endothelial progenitor cells, are capable of self-renewal and de novo vessel formation, and are known key regulators of vascular integrity and homeostasis. Numerous studies have found that exposure to hostile environment during the fetal development exerts a profound influence on the level and function of ECFCs, which may be the underlying factor linking endothelial dysfunction to cardiovascular disease of the offspring in later life. Herein, we focus on the latest findings regarding the effects of pregnancy-related disorders on the frequency and function of fetal ECFCs. Subsequently, we discuss about placental ECFCs and put forward some details that should be paid attention to in the process of ECFC isolation and culture. Overall, the information presented in this review highlight the potential of ECFCs as a future biomarker or even therapeutic targets for the pregnancy-related adverse maternal and fetal outcomes.

Endothelial progenitor cells in pregnancy-related diseases

Placental neovascularization plays a crucial role in fetomaternal circulation throughout pregnancy and is dysregulated in several pregnancy-related diseases, including preeclampsia, gestational diabetes mellitus, and fetal growth restriction. Endothelial progenitor cells (EPCs) are a heterogeneous population of cells that differentiate into mature endothelial cells, which influence vascular homeostasis, neovascularization, and endothelial repair. Since their discovery in 1997 by Asahara et al., the role of EPCs in vascular biology has garnered a lot of interest. However, although pregnancy-related conditions are associated with changes in the number and function of EPCs, the reported findings are conflicting. This review discusses the discovery, isolation, and classification of EPCs and highlights discrepancies between current studies. Overviews of how various diseases affect the numbers and functions of EPCs, the role of EPCs as biomarkers of pregnancy disorders, and the potential therapeutic applications involving EPCs are also provided.

Fetal endothelial colony-forming cell impairment after maternal kidney transplantation

BACKGROUND

Successful pregnancies are nowadays possible after kidney transplantation but are associated with a higher incidence of maternal and fetal complications. Immunosuppressive therapy causes cardiovascular side effects but must be maintained during pregnancy. Little is known about the consequences of maternal kidney transplantation on offspring's endothelial health. Endothelial colony forming cells (ECFCs) represent a highly proliferative subtype of endothelial progenitor cells and are crucial for vascular homeostasis, repair and neovascularization. Therefore, we investigated whether maternal kidney transplantation affects fetal ECFCs' characteristics.

METHODS

ECFCs were isolated from umbilical cord blood of uncomplicated and post-kidney-transplant pregnancies and analyzed for their functional abilities with proliferation, cell migration, centrosome orientation and angiogenesis assays. Further, ECFCs from uncomplicated pregnancies were exposed to either umbilical cord serum from uncomplicated or post-kidney-transplant pregnancies.

RESULTS

Post-kidney-transplant ECFCs showed significantly less proliferation, less migration and less angiogenesis compared to control ECFCs. The presence of post-kidney-transplant umbilical cord serum led to similar functional aberrations of ECFCs from uncomplicated pregnancies.

CONCLUSIONS

These pilot data demonstrate differences in ECFCs' biological characteristics in offspring of women after kidney transplantation. Further studies are needed to monitor offspring's long-term cardiovascular development and to assess possible causal relationships with immunosuppressants, uremia and maternal cardiovascular alterations.

IMPACT

Pregnancy after kidney transplantation has become more common in the past years but is associated with higher complications for mother and offspring. Little is known of the impact of maternal kidney transplantation and the mandatory immunosuppressive therapy on offspring vascular development. In this study we are the first to address and detect an impairment of endothelial progenitor cell function in offspring of kidney-transplanted mothers. Serum from post-transplant pregnancies also causes negative effects on ECFCs' function. Clinical studies should focus on long-term monitoring of offspring's cardiovascular health.

Mild or Moderate COVID-19 during Pregnancy Does Not Affect the Content of CD34+ Hematopoietic Stem Cells in Umbilical Cord Blood of Newborns

The study included umbilical cord blood samples (n=64) intended for cryogenic storage of hematopoietic stem cells and obtained from patients with a history of mild and moderate forms of COVID-19 during pregnancy. The control group was composed of samples (n=746) obtained from healthy women in labor. A comparative analysis of the volume of cord blood collected, the total leukocyte count, the relative and absolute content of cells with the CD34⁺/CD45⁺ phenotype revealed no significant differences between the groups.

Preliminary Interpretations of Epigenetic Profiling of Cord Blood in Preeclampsia

Preeclampsia (PE) is characterized by new-onset hypertension after 20 weeks of pregnancy and results in high maternal and fetal mortality worldwide. It has been reported that PE is associated with abnormalities in the umbilical cord and cord blood. However, previous studies were focused primarily on the transcriptomics level, while the underlying gene regulatory landscapes are still unclear. Thus, we performed the Assay for Transposase-Accessible Chromatin with high-throughput sequencing (ATAC-seq) using the umbilical cord blood samples collected from a patient with superimposed PE and three healthy donors to uncover the chromatin accessibility changes attributed to PE. We have identified genes associated with immunomodulation and hypoxia response that have higher chromatin accessibility close to their transcription start sites. Motif analysis indicated that the GATA family transcription factor binding was enriched in PE and may play an essential regulatory role in the disease progression. Overall, our findings provide an overview of gene regulatory programs and the corresponding downstream pathways associated with PE that may influence the placenta function and fetal growth.

Hydrogen sulfide content in pregnant women with preeclampsia in late gestation and their newborns

We examined 70 women who were 22-40 weeks pregnant and their newborns. Of these, 15 women with moderate PE made up group 1, 22 women with severe PE-group 2, and 55 women with uncomplicated pregnancy without hypertensive disorders - the control group. Blood was collected from women when they were admitted to the clinic, and blood was taken from newborns for 3-5 days of life. The concentration of hydrogen sulfide was determined by the method of K. Qu et al [17]. There was a decrease in the level of hydrogen sulfide in the blood serum of women whose pregnancy was complicated by severe preeclampsia. In newborns born to mothers with preeclampsia, an increase in the concentration of hydrogen sulfide was detected in the blood, which is probably a compensatory reaction aimed at restoring vascular homeostasis during early postnatal adaptation.

Evaluation of oxidative stress and antioxidant activity in women with moderate and severe preeclampsia in the third trimester of pregnancy and their newborns

We examined 66 women who were 22-40 weeks pregnant and their newborns. Of these, 15 women with moderate PE were in group 1, 22 women with severe PE were in group 2, and 55 women with uncomplicated pregnancy without hypertensive disorders were in the control group. Blood was taken from women when they were admitted to the clinic, and newborns ' blood was taken for 3-5 days of life. Free radical oxidation and antioxidant activity were evaluated by induced chemiluminescence. It was found that in patients with severe and moderate preeclampsia, the development of oxidative stress is accompanied by a weakening of antioxidant activity. In newborns born to mothers with preeclampsia, oxidative stress is accompanied by a compensatory increase in antioxidant activity.

Improved placental vascular repair in a rat preeclampsia model by implantation of endothelial progenitor cells treated with platelet microparticles

Objective: To detect the role of endothelial progenitor cells (EPCs) treated with platelet microparticles (PMPs) in preeclampsia. Methods: EPCs treated with/without PMPs were labeled and injected to PE rats. The differentiation of EPCs, the change of endothelial nitric oxide synthase (eNOS), blood pressure and proteinuria were measured. The blood pressure and proteinuria increased in each of PE groups, and were improved by EPCs which was strengthened by PMPs. Transplantation of EPCs increased placental angiogenesis. The trend of change of NO was the same as blood pressure. Conclusion: Transplantation of EPCs treated with PMPs improved blood pressure and proteinuria more effectively.

CD-34+ and VE-cadherin+ endothelial progenitor cells in preeclampsia and normotensive pregnancies

OBJECTIVE

The objective of our study was to determine levels of endothelial progenitor cells (EPCs) in preeclampsia and normotensive pregnant women.

STUDY DESIGN

Prospective cohort study of women with preeclampsia and normotensive pregnancies. EPCs were estimated by flow cytometry. Multiple linear regression was used to assess the association of EPCs with preeclampsia adjusting for maternal age, body mass index (BMI), gestation and ethnicity.

MAIN OUTCOME MEASURE

Levels of EPCs in preeclampsia and normotensive pregnancies, with CD-34 and vascular endothelial (VE)-cadherin as markers of EPCs. VE-cadherin is an endothelial cell adhesion molecule used to delineate endothelial lineage of EPCs.

RESULTS

There were thirty women in the preeclampsia group and thirty-three in the normotensive group. The two groups were similar except for the BMI and blood pressures, which were higher in preeclampsia. On multiple linear regression, EPCs numbers were significantly higher by 29 (95% confidence interval 11.7-46.6, p = 0.001) in preeclampsia compared to the normotensive group. There was significant positive correlation between EPCs and systolic blood pressure in preeclampsia (Spearman correlation coefficient 0.39, p = 0.03).

CONCLUSION

Although widely used in cardiovascular disease other than preeclampsia, this is the first study using VE-cadherin as a marker of endothelial lineage to define EPCs in preeclampsia. Our results suggest the higher number of EPCs in preeclampsia may be a response of the bone marrow to endothelial injury.

Absent or Excessive Corpus Luteum Number Is Associated With Altered Maternal Vascular Health in Early Pregnancy

Identifying modifiable factors that contribute to preeclampsia risk associated with assisted reproduction can improve maternal health. Vascular dysfunction predates clinical presentation of preeclampsia. Therefore, we examined if a nonphysiological hormonal milieu, a modifiable state, affects maternal vascular health in early pregnancy. Blood pressure, endothelial function, circulating endothelial progenitor cell numbers, lipid levels, and corpus luteum (CL) hormones were compared in a prospective cohort of women with infertility history based on number of CL: 0 CL (programmed frozen embryo transfer [FET], N=18); 1 CL (spontaneous conception [N=16] and natural cycle FET [N=12]); or >3 CL associated with in vitro fertilization [N=11]. Women with 0 or >3 CL lacked the drop in mean arterial blood pressure compared with those with 1 CL (both P=0.05). Reactive hyperemia index was impaired in women with 0 CL compared with 1 CL ( P=0.04) while baseline pulse wave amplitude was higher with > 3 CL compared with 1 CL ( P=0.01) or 0 CL ( P=0.01). Comparing only FET cycles, a lower reactive hyperemia index and a higher augmentation index is noted in FETs with suppressed CL compared with FETs in a natural cycle (both P=0.03). The number of angiogenic and nonangiogenic circulating endothelial progenitor cell numbers was lower in the absence of a CL in FETs ( P=0.01 and P=0.03). Vascular health in early pregnancy is altered in women with aberrant numbers of CL (0 or >3) and might represent insufficient cardiovascular adaptation contributing to an increased risk of preeclampsia.

CD133+/C-kit+Lin- endothelial progenitor cells in fetal circulation demonstrate impaired differentiation potency in severe preeclampsia

OBJECTIVES

Individuals delivered from preeclamptic pregnancies exhibit a long-term increased risk of developing cardiovascular and metabolic diseases, likely caused by aberrant fetal cell reprogramming incurred in utero. The present study investigated the functional impairment and epigenetic changes exhibited by endothelial progenitor cells derived from offspring born to preeclamptic pregnancies.

STUDY DESIGN

The capacity of CD133⁺/C-kit⁺/Lin^- (CKL^-) human umbilical cord blood endothelial progenitor cells (EPCs) derived from gestationally matched normal and preeclamptic (n = 10 each) pregnancies to differentiate to form outgrowth endothelial cells (OECs) was assessed by observing both their morphology, and the number and size of generated OECs colonies. Likewise, OECs angiogenic function was evaluated via migration, adhesion, and tube-formation assays. EPCs from preeclampsia were cultured in normal-, and preeclampsia-derived serum-conditioned media to assess the effects of environmental factors on EPC differentiation potency and OEC angiogenic function, and finally, EPCs H3K4, H3K9, and H3K27 trimethylation levels were assayed.

RESULTS

The preeclampsia-derived CKL^- EPCs exhibited decreased H3K4 and H3K9 trimethylation levels, significantly delayed differentiation times, and a significant reduction in both their number of generated OECs colonies, and exhibited reduced OECs migration, adhesion, and tube formation activities compared to those achieved by the normal-derived EPCs. Interestingly, the reduced differentiation potency of the preeclampsia-derived EPCs was not rescued via exposure to normal serum.

CONCLUSIONS

Exposure to preeclampsia significantly and irreversibly reduced CKL^- EPC differentiation potency and OEC angiogenic function, likely reflecting incurred irreversible epigenetic changes.

Recent advances in antenatal factors predisposing to bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) remains a major cause of late morbidities and death after preterm birth. BPD is characterized by an arrest of vascular and alveolar growth and high risk for pulmonary hypertension; yet mechanisms contributing to its pathogenesis and early strategies to prevent BPD are poorly understood. Strong epidemiologic studies have shown that the "new BPD" reflects the long-lasting impact of antenatal factors on lung development, partly due to placental dysfunction, as reflected in recent data from animal models. Improved understanding of mechanisms through which antenatal stress alters placental function and contributes to BPD may lead to preventive therapies.

Examining the role of unmeasured confounding in mediation analysis with genetic and genomic applications

Background

In mediation analysis if unmeasured confounding is present, the estimates for the direct and mediated effects may be over or under estimated. Most methods for the sensitivity analysis of unmeasured confounding in mediation have focused on the mediator-outcome relationship.

Results

The Umediation R package enables the user to simulate unmeasured confounding of the exposure-mediator, exposure-outcome, and mediator-outcome relationships in order to see how the results of the mediation analysis would change in the presence of unmeasured confounding. We apply the Umediation package to the Genetic Epidemiology of Chronic Obstructive Pulmonary Disease (COPDGene) study to examine the role of unmeasured confounding due to population stratification on the effect of a single nucleotide polymorphism (SNP) in the CHRNA5/3/B4 locus on pulmonary function decline as mediated by cigarette smoking.

Conclusions

Umediation is a flexible R package that examines the role of unmeasured confounding in mediation analysis allowing for normally distributed or Bernoulli distributed exposures, outcomes, mediators, measured confounders, and unmeasured confounders. Umediation also accommodates multiple measured confounders, multiple unmeasured confounders, and allows for a mediator-exposure interaction on the outcome. Umediation is available as an R package at https://github.com/SharonLutz/Umediation A tutorial on how to install and use the Umediation package is available in the Additional file 1.

Electronic supplementary material

The online version of this article (doi:10.1186/s12859-017-1749-y) contains supplementary material, which is available to authorized users.

Endothelial Progenitor Cells of the Human Placenta and Fetoplacental Circulation: A Potential Link to Fetal, Neonatal, and Long-term Health

The fetoplacental circulation plays a key role in both short- and long-term outcomes, and aberrant flow indices as manifested by abnormal fetal Doppler velocimetry within this compartment have been associated with significant adverse consequences. These include fetal growth restriction, which often coexists with preeclampsia, and long-lasting medical issues as a result of both the underlying pathology and prematurity such as bronchopulmonary dysplasia, chronic lung disease, and neurodevelopmental delay. Furthermore, it is also clear that exposure to an abnormal in utero environment increases risk for long-term, adulthood issues such as cardiovascular disease. Endothelial progenitor cells (EPCs) have been implicated in vasculogenesis and angiogenesis, and they have been isolated from both human placenta and umbilical cord blood. This review outlines the extensive nomenclature of EPCs, summarizes existing literature surrounding human placental and umbilical cord blood EPCs, explores their potential role in pregnancy complications and adverse perinatal outcome, and highlights key areas where future investigations are needed.