Estrogen-mediated endothelial progenitor cell biology and kinetics for physiological postnatal vasculogenesis

Stem cells and female reproduction: endometrial physiology, disease and therapy

The human endometrium, a dynamic tissue that undergoes cyclical shedding, repair, regeneration, and remodeling, relies on progenitor stem cells for replenishment. Bone marrow-derived mesenchymal stem cells (BM-MSCs) also may play a crucial role in the physiological process of endometrial regeneration, augmenting endometrial repair, supporting pregnancy, and thereby making a major contribution to reproduction. Notably, defective or inappropriate recruitment and engraftment of stem cells are implicated in various reproductive diseases, including endometriosis, highlighting the potential therapeutic avenues offered by stem cell-targeted interventions. Endometrial progenitor cells have shown promise in improving pregnancy outcomes and addressing infertility issues. Furthermore, BM-MSCs demonstrate the potential to reverse pathologies, including Asherman's syndrome and thin endometrium, offering novel approaches to treating infertility, implantation failure, and recurrent pregnancy loss. Mobilization of endogenous stem cells to areas of pathology through chemoattractants also presents a promising strategy for targeted therapy. Finally, endometrium-derived mesenchymal stem cells, characterized by their multipotent nature and ease of collection through minimally invasive techniques, hold promise in a wide range of reproductive and non-reproductive pathologies, including diabetes, kidney disease, Parkinson's disease, or cardiac disorders. As the best of our knowledge of stem cell biology continues to grow, the incorporation of stem cell-based therapies into clinical practice presents significant potential to transform reproductive medicine and enhance patient outcomes.

Endothelial characteristics of cardiac stem cell antigen-1 expressing cells and their relevance to right ventricular adaptation

A growing body of evidence suggest that the stem cell antigen-1 expressing (Sca-1+) cells in the heart may be the cardiac endothelial stem/progenitor cells. Their endothelial cell (EC) functions, and their role in right ventricle (RV) physiology and pathophysiology of right heart failure (RHF) remains poorly defined. This study investigated EC characteristics of rat cardiac Sca-1+ cells, assessed spatial distribution and studied changes in Sca-1+ cells during RV remodelling in monocrotaline (MCT) model of pulmonary hypertension and RV remodeling. First, flow-cytometry analysis of adult male and female Sprague Dawley (SD) and Fischer CDF rat heart cells was performed, and we observed that the majority of Sca-1+ cells also expressed CD31, an EC marker. Furthermore, Sca-1+ cells showed acetylated low-density lipoprotein (ac-LDL) uptake and lectin binding similar to CD31+ cells from the same heart. The Sca-1+ cells also demonstrated network formation when plated on Matrigel. In the MCT treated rats, we observed increase in RV hypertrophy that correlated with the reduction in the abundance of Sca-1+CD31+ cells in the RV. Together, the cardiac Sca-1+ cells in the heart are endothelial stem/progenitor-like cells. These cells have higher abundance in the RV and may play a role in RV adaptation.

Effectiveness of exercise training on arterial stiffness and blood pressure among postmenopausal women: a systematic review and meta-analysis

BACKGROUND

The acute and long-term benefits of exercise training on cardiovascular health have been well established. The systematic review and meta-analysis aimed to systematically assess the effectiveness of exercise training on arterial stiffness and blood pressure among postmenopausal women with elevated blood pressure.

METHODS

A comprehensive search was conducted on PubMed, Embase, Web of Science, ProQuest, Cochrane Library, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov website from inception to September 30, 2023, to identify the randomized controlled trials (RCTs), which evaluated the effectiveness of exercise training on arterial stiffness and blood pressure in postmenopausal women. Standardized mean differences (SMD), weighted mean differences (WMD), and 95% confidence intervals (95% CIs) were calculated using random/fixed effects models. Quality assessment was performed using the modified Jadad scale and the Cochrane Risk of Bias Tool. Sensitivity analysis and subgroup analysis were conducted based on drug dosage, treatment duration, and age of administration to further explore potential heterogeneity. Funnel plots were performed to assess publication bias and Begg's regression test was carried out for funnel plot asymmetry.

RESULTS

Twenty-two RCTs involving 1978 participants were included in the quantitative analysis. The mean quality of eligible studies was 4.2 out of 7 based on the modified Jadad scale. The results indicated that exercise training had a significant effect on reducing brachial-ankle pulse wave velocity [MD = - 0.69, 95%CI (- 1.11, - 0.27), P = 0.001], decreasing augmentation index (AIx) [MD = - 6.00, 95%CI (- 6.39, - 5.61), P < 0.00001] and AIx normalized to a heart rate of 75 beats per minute (AIx@75%) [MD = - 7.01, 95%CI - 7.91 to - 6.12, P < 0.00001], lowering systolic blood pressure [MD = - 6.19, 95%CI - 9.24 to - 3.15, P < 0.0001], diastolic blood pressure [MD = - 3.57, 95%CI (- 6.10, - 1.03), P = 0.006) and pulse pressure [MD = - 8.52, 95%CI (- 16.27, - 0.76), P = 0.03]. Subgroup analysis revealed that baseline blood pressure levels had a large impact on the effect of exercise training.

CONCLUSIONS

The systematic review and meta-analysis suggested that exercise training may ameliorate arterial stiffness and reduce blood pressure in postmenopausal women with elevated blood pressure. However, the optimal mode of exercise training that improves arterial stiffness and blood pressure in this population requires further investigation.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021211268.

Endometrial and placental stem cells in successful and pathological pregnancies

The endometrium is a dynamic tissue that undergoes extensive remodeling during the menstrual cycle and further gets modified during pregnancy. Different kinds of stem cells are reported in the endometrium. These include epithelial stem cells, endometrial mesenchymal stem cells, side population stem cells, and very small embryonic-like stem cells. Stem cells are also reported in the placenta which includes trophoblast stem cells, side population trophoblast stem cells, and placental mesenchymal stem cells. The endometrial and placental stem cells play a pivotal role in endometrial remodeling and placental vasculogenesis during pregnancy. The dysregulation of stem cell function is reported in various pregnancy complications like preeclampsia, fetal growth restriction, and preterm birth. However, the mechanisms by which it does so are yet elusive. Herein, we review the current knowledge of the different type of stem cells involved in pregnancy initiation and also highlight how their improper functionality leads to pathological pregnancy.

The prospects of cell therapy for endometriosis

Endometriosis is a chronic inflammatory estrogen-dependent disease characterized by the growth of endometrial-like tissue outside the physiological region. Despite the fact that this disease is common, laparoscopic surgery is currently the gold standard in the treatment of endometriosis. In this regard, it is necessary to develop new effective methods of minimally invasive therapy for endometriosis. One of the promising areas in the treatment of endometriosis is cell therapy. Cellular therapy is a vast branch of therapeutic methods with various agents. Potential cell therapies for endometriosis may be based on the principle of targeting aspects of the pathogenesis of the disease: suppression of estrogen receptor activity, angiogenesis, fibrosis, and a decrease in the content of stem cells in endometriosis foci. In addition, immune cells such as NK cells and macrophages may be promising agents for cell therapy of endometriosis. Standing apart in the methods of cell therapy is the replacement therapy of endometriosis. Thus, many studies in the field of the pathogenesis of endometriosis can shed light not only on the causes of the disease and may contribute to the development of new methods for personalized cell therapy of endometriosis.

Endothelial Dysfunction and Cardiovascular Risk in Obstructive Sleep Apnea: A Review Article

Obstructive sleep apnea (OSA) is a respiratory condition during sleep caused by repeated pauses in breathing due to upper airway obstruction. It is estimated that OSA affects 30% of the population, but only 10% are well diagnosed due to the absence of a well-defined symptomatology and poor screening tools for early diagnosis. OSA is associated to an endothelial dysfunction inducing several biological responses such as hypoxia, hypercapnia and oxidative stress, among others. OSA also triggers respiratory, nervous, metabolic, humoral and immunity system activations that increase the possibility of suffering a cardiovascular (CV) disease. In this review, we expose different studies that show the relationship between OSA and endothelial dysfunction and its association with CV pathologies like hypertension, and we define the most well-known treatments and their limitations. Additionally, we describe the potential future directions in OSA research, and we report clinical features such as endothelial progenitor cell alterations that could act as biomarkers for the development of new diagnostic tools and target therapies.

Vitamin K2 Inhibits Hepatocellular Carcinoma Cell Proliferation by Binding to 17β-Hydroxysteroid Dehydrogenase 4

Our previous studies have proved that 17β-hydroxysteroid dehydrogenase 4 (HSD17B4) is a novel proliferation-promoting protein. The overexpression of HSD17B4 promotes hepatocellular carcinoma (HCC) cell proliferation. Vitamin K2 (VK2), a fat-soluble vitamin, has the function of promoting coagulation and can inhibit the progression of liver cancer. A previous study demonstrated that VK2 could bind to HSD17B4 in HepG2 cells. However, the mechanism of VK2 in inhibiting HCC cell proliferation is not clear. In this study, we investigate whether VK2 can inhibit the proliferation of HCC cell induced by HSD17B4 and the possible mechanism. We detected the effect of VK2 on HSD17B4-induced HCC cell proliferation, and the activation of STAT3, AKT, and MEK/ERK signaling pathways. We measured the effect of HSD17B4 on the growth of transplanted tumor and the inhibitory effect of VK2. Our results indicated that VK2 directly binds to HSD17B4, but does not affect the expression of HSD17B4, to inhibit the proliferation of HCC cells by inhibiting the activation of Akt and MEK/ERK signaling pathways, leading to decreased STAT3 activation. VK2 also inhibited the growth of HSD17B4-induced transplanted tumors. These findings provide a theoretical and experimental basis for possible future prevention and treatment of HCC using VK2.

Autologous mesenchymal stem cells in the treatment of spinal aneurysmal bone cyst

PURPOSE

We retrospectively analyzed a cohort of patients treated at our Centre with bone marrow concentrated (BMC) injection for aneurysmal bone cyst (ABC) of the spine, in order to propose this treatment as a valid alternative for the management of ABCs.

METHODS

Fourteen patients (6 male, 8 female) were treated between June 2014 to December 2019 with BMC injection for ABC of the spine. The mean age was 15.5 years. The mean follow up was 37.4 months (range 12-60 months). The dimension of the cyst and the degree of ossification were measured by Computed Tomography (CT) scans before the treatment and during follow-up visits.

RESULTS

Six patients received a single dose of BMC, five patients received two doses and in three patients three doses of BMC were administered. The mean ossification of the cyst (expressed in Hounsfield units) increased statistically from 43.48 ± 2.36 HU to 161.71 ± 23.48 HU during follow-up time and the ossification was associated to an improvement of the clinical outcomes. The mean ossification over time was significantly higher in patients treated with a single injection compared to patients treated with multiple injections. No significant difference in ossification was found between cervical and non-cervical localization of the cyst. Moreover, the initial size of the cyst was not statistically associated with the degree of ossification during follow-up CONCLUSIONS: Results of this paper reinforce our previous evidence on the use of BMC as a valid alternative for spinal ABC management when SAE treatment is contraindicated or ineffective.

A Meta-Analysis of the Effects of Aerobic Exercise on the Basal Level of Endothelial Progenitor Cells in Middle-Aged and Older Adults

Circulatory endothelial progenitor cells (EPCs) play an important role in repairing damaged vascular endothelium and preventing cardiovascular diseases. The decrease in level of circulating EPCs in middle-aged and older adults can lead to an increase in cardiovascular events. Researchers have carried out several studies on the effects of aerobic exercise on circulating EPCs in middle-aged and older adults, but the results vary from one study to another. The aim of this study therefore is to systematically evaluate the effect of aerobic exercise on the basal level of circulating EPCs in middle-aged and older adults by meta-analysis. Randomized controlled trial studies on the effects of aerobic exercise on EPCs were searched for from CNKI, PubMed, EBSCO, Cochrane Library, Web of Science, and Embase databases. The literature was screened according to inclusion and exclusion criteria, research data were extracted, and the literature quality was evaluated by Cochrane scale. Software Review Manager (version 5.3) and Stata (version 15.0) were used for data analysis. A total of nine articles were included in this analysis, including 165 participants (40 healthy adults and 125 patients) who received exercise interventions and 162 participants (40 healthy adults and 122 patients) who served as the control, with an age range from 58 to 70 years. The meta-analysis found that long-term (≥12 weeks) aerobic exercise could improve the level of EPCs in the peripheral circulation (standardized mean differences [SMD] = 0.53, 95% confidence interval [0.30, 0.76], p < .01). The subgroup analysis found that aerobic exercise improved EPCs in healthy people better than in people with cardiovascular disease and that the intervention time needs to be over 12 weeks to have a significant impact. In conclusion, the authors suggest that middle-aged and older adults can improve their EPCs quantity by engaging in moderate-intensity aerobic exercise four to five times per week for no less than 12 weeks to reduce the risk of cardiovascular disease.

Long Term Response to Circulating Angiogenic Cells, Unstimulated or Atherosclerotic Pre-Conditioned, in Critical Limb Ischemic Mice

Critical limb ischemia (CLI), the most severe form of peripheral artery disease, results from the blockade of peripheral vessels, usually correlated to atherosclerosis. Currently, endovascular and surgical revascularization strategies cannot be applied to all patients due to related comorbidities, and even so, most patients require re-intervention or amputation within a year. Circulating angiogenic cells (CACs) constitute a good alternative as CLI cell therapy due to their vascular regenerative potential, although the mechanisms of action of these cells, as well as their response to pathological conditions, remain unclear. Previously, we have shown that CACs enhance angiogenesis/arteriogenesis from the first days of administration in CLI mice. Also, the incubation ex vivo of these cells with factors secreted by atherosclerotic plaques promotes their activation and mobilization. Herein, we have evaluated the long-term effect of CACs administration in CLI mice, whether pre-stimulated or not with atherosclerotic factors. Remarkably, mice receiving CACs and moreover, pre-stimulated CACs, presented the highest blood flow recovery, lower progression of ischemic symptoms, and decrease of immune cells recruitment. In addition, many proteins potentially involved, like CD44 or matrix metalloproteinase 9 (MMP9), up-regulated in response to ischemia and decreased after CACs administration, were identified by a quantitative proteomics approach. Overall, our data suggest that pre-stimulation of CACs with atherosclerotic factors might potentiate the regenerative properties of these cells in vivo.

Insights from the Menstrual Cycle in Pulmonary Arterial Hypertension

Rationale: Sex hormones play a role in pulmonary arterial hypertension (PAH), but the menstrual cycle has never been studied.Objectives: We conducted a prospective observational study of eight women with stable PAH and 20 healthy controls over one cycle.Methods: Participants completed four study visits 1 week apart starting on the first day of menstruation. Relationships between sex hormones, hormone metabolites, and extracellular vesicle microRNA (miRNA) expression and clinical markers were compared with generalized linear mixed modeling.Results: Women with PAH had higher but less variable estradiol (E2) levels (P < 0.001) that tracked with 6-minute walk distance (P < 0.001), N-terminal prohormone of brain natriuretic peptide (P = 0.03) levels, and tricuspid annular plane systolic excursion (P < 0.01); the direction of these associations depended on menstrual phase. Dehydroepiandrosterone sulfate (DHEA-S) levels were lower in women with PAH (all visits, P < 0.001). In PAH, each 100-μg/dl increase in DHEA-S was associated with a 127-m increase in 6-minute walk distance (P < 0.001) and was moderated by the cardioprotective E2 metabolite 2-methoxyestrone (P < 0.001). As DHEA-S increased, N-terminal prohormone of brain natriuretic peptide levels decreased (P = 0.001). Expression of extracellular vesicle miRNAs-21, -29c, and -376a was higher in PAH, moderated by E2 and DHEA-S levels, and tracked with hormone-associated changes in clinical measures.Conclusions: Women with PAH have fluctuations in cardiopulmonary function during menstruation driven by E2 and DHEA-S. These hormones in turn influence transcription of extracellular vesicle miRNAs implicated in the pathobiology of pulmonary vascular disease and cancer.

Regulatory Network Analysis in Estradiol-Treated Human Endothelial Cells

Background/Aims: Estrogen has been reported to have beneficial effects on vascular biology through direct actions on endothelium. Together with transcription factors, miRNAs are the major drivers of gene expression and signaling networks. The objective of this study was to identify a comprehensive regulatory network (miRNA–transcription factor–downstream genes) that controls the transcriptomic changes observed in endothelial cells exposed to estradiol. Methods: miRNA/mRNA interactions were assembled using our previous microarray data of human umbilical vein endothelial cells (HUVEC) treated with 17β-estradiol (E2) (1 nmol/L, 24 h). miRNA–mRNA pairings and their associated canonical pathways were determined using Ingenuity Pathway Analysis software. Transcription factors were identified among the miRNA-regulated genes. Transcription factor downstream target genes were predicted by consensus transcription factor binding sites in the promoter region of E2-regulated genes by using JASPAR and TRANSFAC tools in Enrichr software. Results: miRNA–target pairings were filtered by using differentially expressed miRNAs and mRNAs characterized by a regulatory relationship according to miRNA target prediction databases. The analysis identified 588 miRNA–target interactions between 102 miRNAs and 588 targets. Specifically, 63 upregulated miRNAs interacted with 295 downregulated targets, while 39 downregulated miRNAs were paired with 293 upregulated mRNA targets. Functional characterization of miRNA/mRNA association analysis highlighted hypoxia signaling, integrin, ephrin receptor signaling and regulation of actin-based motility by Rho among the canonical pathways regulated by E2 in HUVEC. Transcription factors and downstream genes analysis revealed eight networks, including those mediated by JUN and REPIN1, which are associated with cadherin binding and cell adhesion molecule binding pathways. Conclusion: This study identifies regulatory networks obtained by integrative microarray analysis and provides additional insights into the way estradiol could regulate endothelial function in human endothelial cells.

Endometrial stem cells: origin, biological function, and therapeutic applications for reproductive disorders

PURPOSE OF REVIEW

Endometrial stem cells (ESCs) are multipotent cells that are thought to originate locally in the endometrium as well as in the bone marrow (BM). They have remarkable plasticity and hold promise as an autologous source for regenerative medicine. This review focuses on recent studies that have advanced our understanding of the biology and function of ESCs and BM-derived stem cells (BMDSCs) as related to physiological reproductive processes and pathologies. Moreover, it reviews recent data on potential therapeutic applications of stem cells to endometrial disorders that lead to reproductive failure.

RECENT FINDINGS

Growing evidence from basic and preclinical studies suggests that ESCs participate in endometrial tissue regeneration and repair. Recent evidence also suggests that ESCs and BMDSCs play important roles in physiological reproductive functions including decidualization, implantation, pregnancy maintenance, and postpartum uterine remodeling. Initial preclinical and clinical studies with ESCs and BMDSCs suggest they have the potential to provide new therapies for various endometrial disorders associated with reproductive failure.

SUMMARY

Uterine ESCs and BMDSCs appear to play an important biological role in reproductive success and failure, and have the potential to become treatment targets for reproductive diseases including recurrent implantation failure, thin endometrium, Asherman, and recurrent pregnancy loss.

Tumors modulate fenestrated vascular beds and host endocrine status

Allograft and xenograft transplantation into a mouse host is frequently utilized to study cancer biology, tumor behavior, and response to treatment. Preclinical studies employing these models often focus solely upon the intra-tumoral effects of a given treatment, without consideration of systemic toxicity or tumor-host interaction, nor whether this latter relationship could modulate the toxicologic response to therapy. Here it is demonstrated that the implantation and growth of a range of human- and mouse-derived cell lines leads to structural vascular and, potentially, functional changes within peripheral endocrine tissues, a process that could conceivably ameliorate the severity of anti-angiogenic-induced fenestrated vessel attenuation. Observations suggest a multifactorial process, which may involve host- and tumor-derived cytokines/growth factors, and the liberation of myeloid-derived suppressor cells. Further investigation revealed a structurally comparable response to the administration of exogenous estrogen. These findings, in addition to providing insight into the development of clinical anti-angiogenic "adaptation," may be of significance within the "cancer-cachexia" and cancer-related anemia syndromes in man.

The Effect of Novel Medical Nonhormonal Treatments on the Angiogenesis of Endometriotic Lesions

Importance

Irrespective of the precise mechanisms leading to endometriosis, angiogenesis is essential for the establishment and long-term proliferation of the disease. As current surgical and medical management options for women with endometriosis have substantial drawbacks and limitations, novel agents are needed and molecules targeting the angiogenic cascade could serve as potential candidates.

Objective

Our aim was to review current data about the role of angiogenesis in the pathophysiology of endometriosis and summarize the novel antiangiogenic agents that could be potentially used in clinical management of patients with endometriosis.

Evidence Acquisition

Original research and review articles were retrieved through a computerized literature search.

Results

Loss of balance between angiogenic activators and suppressors triggers the nonphysiological angiogenesis observed in endometriotic lesions. Several proangiogenic mediators have been identified and most of them have demonstrated increased concentrations in the peritoneal fluid and/or serum of women with endometriosis. Among the antiangiogenic molecules, anti-vascular endothelial growth factor agents, dopamine agonists, romidepsin, and statins have shown the most promising results so far.

Conclusions and Relevance

Given the limitations of current treatments of endometriosis, there is a need for novel, more efficient agents. Antiangiogenic molecules could be used potentially in clinical management of women with endometriosis; however, their safety and efficiency should be carefully assessed prior to that. Further large prospective trials in humans are needed before any treatment is introduced into daily clinical practice.

[Problems and prospects of cell therapy for critical ischaemia of lower limbs]

BACKGROUND

Cell therapy was proposed as a procedure of indirect revascularization for patients with critical ischaemia of lower extremities for whom endovascular and surgical revascularization is impossible. We present herein a review of the state of the art of studies in the field of cell therapy of this cohort of patients.

BASIC PROVISIONS

Cell therapy has proved safe, however, the results of studies of efficacy are relatively ambiguous and unconvincing. The number of patients in separately taken clinical trials is minimal. The reviewed studies differed not only by heterogeneity of the cell types used but by the routes of administration of cells (cells were delivered either intramuscularly (predominantly) or intraarterially) and the duration of follow up (time of assessment and duration of follow up varied from 1 month to 2 years). One of the problems became the lack of the routine study of the angiogenic potential of stem cells prior to their clinical application. It is known that the angiogenic activity of multipotent cells of apparently healthy patients may differ from that of patients suffering from atherosclerosis, chronic renal failure, diabetes.

CONCLUSIONS

It is supposed that treatment with stem cells or precursor cells is more efficient as compared to protein or gene therapy not only owing to direct vasculogenic properties but a paracrine action through excretion of proangiogenic biologically active substances. More studies with larger cohorts are necessary to provide stronger safety and efficacy data on cell therapy. Besides, a promising trend in the field of cellular approaches is modulation of regenerative capability of stem cells, which may help overcome difficulties in understanding the place of cell therapy in therapeutic angiogenesis.

Effect of cold stress on ovarian & uterine microcirculation in rats and the role of endothelin system

BACKGROUND

Cold, an environmental factor, induces many reproductive diseases. It is known that endothelin (ET) is a potent vasoconstrictor, and cold stress can increase the expression of ET and its receptors. The cold stress rat model was developed to examine two parameters: (1) the effects of cold stress on ovarian and uterine morphology, function, and microvascular circulation and (2) possible mechanisms of ET and its receptors involved in cold stress-induced menstruation disorders.

METHODS

The rat cold stress model was prepared with an ice water bath. The estrous cycle was observed by methylene blue and hematoxylin and eosin (H&E) staining. Serum estradiol 2 (E₂), testosterone (T), progesterone (P) were detected by radioimmunoassay. Hemorheology indices were measured. The real-time blood flow of auricle and uterine surfaces was measured. Expressions of CD34 and α-SMA in ovarian and uterine tissues were detected by immunohistochemistry. ET-1 contents in serum were tested, and expressions of ET-receptor types A and B (ET-AR and ET-BR) in ovarian tissues were detected via Western blotting.

RESULTS

Cold stress extended the estrous cycle, thereby causing reproductive hormone disorder, imbalance of local endothelin/nitric oxide expression, and microcirculation disturbance. Cold-stress led to up-regulation of ET-AR expression and protein and down-regulation of ET-BR expression in rats.

CONCLUSIONS

This study suggests that the reason for cold stress-induced dysfunction in reproductive organs may be closely related to the imbalance of ET-1 and its receptor expressions, leading to microvascular circulation disorders in local tissues.

The effects of transplanted mesenchymal stem cells treated with 17-b estradiol on experimental autoimmune encephalomyelitis

The present study was conducted aimed at exploring the modulatory effects of 17-b estradiol (17-bED) on mesenchymal stem cells (MSCs) in the EAE (experimental autoimmune encephalomyelitis) animal model of multiple sclerosis (MS). Following the isolation of bone marrow-derived MSCs from the bilateral femurs and tibias of the male Wistar rats, the cells were harvested and cultured in the presence of 100 nM 17-bED for 24 h. EAE was induced in male Wistar rats (8-12 weeks old) using guinea pig spinal cord homogenate, in combination with the complete Freund's adjuvant. The MSC therapy was triggered when all of the animals obtained a disability score. The symptoms were monitored on a daily basis throughout the study until the rats were euthanized. The mRNA expression of cytokines, including IL-17, IFN-γ, TNF-α, IL-10, IL-4, and TGF-β together with MMP8 and MMP9 as the family members of matrix metalloproteinases (MMPs) in the brain and spinal cord tissues were examined using real-time PCR. The levels of splenocytes-originated IL-10 and IFN-γ cytokines were also measured by ELISA. The MTT-based research findings showed that the infiltration of lymphocytes into the spleen decreased considerably. It was also observed that the mRNA expression of proinflammatory cytokines decreased significantly, while the mRNA levels of anti-inflammatory cytokines increased remarkably. It was also found that the mRNA levels of the examined matrix metalloproteinases (MMP8 and MMP9) were downregulated significantly. The findings of the present study indicated that the administration of 17-bED enhanced the efficacy of MSCs transplantation and modulated immune responses relatively in the EAE model, via the regulation of either pro- or anti-inflammatory cytokines and matrix metalloproteinases.

Adult bone marrow progenitors become decidual cells and contribute to embryo implantation and pregnancy

Decidua is a transient uterine tissue shared by mammals with hemochorial placenta and is essential for pregnancy. The decidua is infiltrated by many immune cells promoting pregnancy. Adult bone marrow (BM)-derived cells (BMDCs) differentiate into rare populations of nonhematopoietic endometrial cells in the uterus. However, whether adult BMDCs become nonhematopoietic decidual cells and contribute functionally to pregnancy is unknown. Here, we show that pregnancy mobilizes mesenchymal stem cells (MSCs) to the circulation and that pregnancy induces considerable adult BMDCs recruitment to decidua, where some differentiate into nonhematopoietic prolactin-expressing decidual cells. To explore the functional importance of nonhematopoietic BMDCs to pregnancy, we used Homeobox a11 (Hoxa11)-deficient mice, having endometrial stromal-specific defects precluding decidualization and successful pregnancy. Hoxa11 expression in BM is restricted to nonhematopoietic cells. BM transplant (BMT) from wild-type (WT) to Hoxa11-/- mice results in stromal expansion, gland formation, and marked decidualization otherwise absent in Hoxa11-/- mice. Moreover, in Hoxa11+/- mice, which have increased pregnancy losses, BMT from WT donors leads to normalized uterine expression of numerous decidualization-related genes and rescue of pregnancy loss. Collectively, these findings reveal that adult BMDCs have a previously unrecognized nonhematopoietic physiologic contribution to decidual stroma, thereby playing important roles in decidualization and pregnancy.

The Potential Role of Circulating Endothelial Cells and Endothelial Progenitor Cells in the Prediction of Left Ventricular Hypertrophy in Hypertensive Patients

Background

The main aim of present study is to evaluate the potential role of circulating endothelial cells (CECs) and endothelial progenitor cells (CEPCs) – representing specific markers of endothelial damage, in the prediction of left ventricular hypertrophy (LVH) in hypertensive patients categorized into two groups; mild (MH) and resistant hypertension (RH).

Materials and Methods

Thirty patients with MH and 28 subjects with RH were involved in the study. In both groups, patients were divided into an LVH and non-LVH group. The control group included 33 age and sex-matched normotensive volunteers. Physical examination, laboratory tests and echocardiography were conducted.

Results

In both the MH and RH group, patients with as well as without LVH demonstrated a higher number of CECs and a lower ratio of CEPCs/CECs as compared to the healthy control. Multiple linear regression analysis showed a positive association of CEPCs with left ventricular mass (LVM) and left ventricular mass index (LVMI), independently of other confounders.

Conclusion

Our results suggest that endothelial injury observed as an elevated CECs number and its impaired regeneration, reflected by a lowered CEPCs/CECs ratio, precede LVH occurrence and may play a significant role in LVH development regardless of the clinical severity of hypertension. Moreover, independent correlation of CEPCs with echocardiographic (ECG) incidences of LVH suggests their potential use as a screening biomarker to stratify the risk of LVH development.

Quality and Quantity-Cultured Murine Endothelial Progenitor Cells Increase Vascularization and Decrease Fibrosis in the Fat Graft

BACKGROUND

Fat grafting has become a valuable technique for soft-tissue reconstruction; however, long-lasting success depends on several determinants. An early blood supply to the transplanted adipocytes is important to prevent ischemia. The recently developed quality and quantity (QQ) culture increases the vasculogenic potential of endothelial progenitor cells. The authors used a murine fat grafting model to address the hypothesis that QQ-cultured endothelial progenitor cells stimulate the establishment of a blood vessel network and increase graft success.

METHODS

c-KitSca-1Lin (KSL) cells were isolated as endothelial progenitor cell precursors from C57BL/6 mice. Adipose tissue was grafted with QQ-cultured KSL cells (QQKSL group), uncultured KSL cells (KSL group), adipose-derived stem cells (ASC group), and a combination (QQKSL+ASC group), and compared to a control group. Five and 10 weeks later, grafts were weighed, histologic and immunohistochemical parameters were evaluated, and gene expression was quantified by quantitative polymerase chain reaction.

RESULTS

The highest vessel density was observed in the combined QQKSL+ASC group (68.0 ± 4.3/mm; p < 0.001) and the QQKSL group (53.9 ± 3.0/mm; p < 0.001). QQKSL cells were engrafted in proximity to the graft vasculature. QQKSL cells decreased the fibrosis percentage (13.8 ± 1.8 percent; p < 0.05). The combined QQKSL+ASC group (22.4 ± 1.8/mm; p < 0.001) showed the fewest local inflammation units. A significant up-regulation of platelet-derived growth factor and adiponectin expression was observed in the QQKSL group and QQKSL+ASC group. Graft weight persistence was not significantly different between groups.

CONCLUSIONS

Supplementing fat grafts with quality and quantity-cultured endothelial progenitor cells improves graft quality by stimulating vascularization. The increased vessel density is associated with less fibrosis, less inflammation, and better adipose tissue integrity. Enriching fat grafts with QQ-cultured endothelial progenitor cells is a potential solution to their clinical shortcomings.

Mechanisms of Sex Disparities in Cardiovascular Function and Remodeling

Epidemiological studies demonstrate disparities between men and women in cardiovascular disease prevalence, clinical symptoms, treatments, and outcomes. Enrollment of women in clinical trials is lower than men, and experimental studies investigating molecular mechanisms and efficacy of certain therapeutics in cardiovascular disease have been primarily conducted in male animals. These practices bias data interpretation and limit the implication of research findings in female clinical populations. This review will focus on the biological origins of sex differences in cardiovascular physiology, health, and disease, with an emphasis on the sex hormones, estrogen and testosterone. First, we will briefly discuss epidemiological evidence of sex disparities in cardiovascular disease prevalence and clinical manifestation. Second, we will describe studies suggesting sexual dimorphism in normal cardiovascular function from fetal life to older age. Third, we will summarize and critically discuss the current literature regarding the molecular mechanisms underlying the effects of estrogens and androgens on cardiac and vascular physiology and the contribution of these hormones to sex differences in cardiovascular disease. Fourth, we will present cardiovascular disease risk factors that are positively associated with the female sex, and thus, contributing to increased cardiovascular risk in women. We conclude that inclusion of both men and women in the investigation of the role of estrogens and androgens in cardiovascular physiology will advance our understanding of the mechanisms underlying sex differences in cardiovascular disease. In addition, investigating the role of sex-specific factors in the development of cardiovascular disease will reduce sex and gender disparities in the treatment and diagnosis of cardiovascular disease. © 2019 American Physiological Society. Compr Physiol 9:375-411, 2019.

Sexual dimorphism in hepatitis B and C and hepatocellular carcinoma

The incidence of viral hepatitis B or C (HBV/HCV) infection and hepatocellular carcinoma is higher in male compared to female populations, showing a faster disease progression and results in a worse overall survival. Indeed, women are in general better protected from viral infections and show a lower risk of death from malignant cancer in comparison to men. Females mount stronger innate and adaptive immune responses than males, and therefore, most of the autoimmune diseases occur predominantly in females. Next to occupational and/or behavioral factors, cellular and molecular differences between the two sexes contribute to this observation. In this review, we will discuss underlying mechanisms that are important for the observed sex-related differences in liver diseases. A better appreciation of these differences between the two sexes might be of value for better and gender-specific treatment options.

Downregulated GTCPH I/BH4 Pathway and Decreased Function of Circulating Endothelial Progenitor Cells and Their Relationship with Endothelial Dysfunction in Overweight Postmenopausal Women

Endothelial progenitor cells (EPCs) have endogenous endothelium-reparative potential, but obesity impairs EPCs. Overweight premenopausal women have a normal number of circulating EPCs with functional activity, but whether EPCs in overweight postmenopausal women can repair obesity-related endothelial damage requires further investigation. For this purpose, we examined the function and number of circulating EPCs, evaluated vascular endothelial function, and explored the underlying mechanism. Compared with normal weight or overweight age-matched men, postmenopausal women (overweight or normal weight) had a diminished number of circulating EPCs and impaired vascular endothelial function, as detected by flow-mediated dilatation. Moreover, GTCPH I expression and the nitric oxide level in overweight postmenopausal women and men were significantly decreased. Together, our findings demonstrate that the number or function of circulating EPCs and endothelial function, which is partially regulated by the GTCPH I/BH4 signaling pathway, is not preserved in overweight postmenopausal women. The GTCPH I/BH4 pathway in circulating EPCs may be a potential therapeutic target for endothelial injury in overweight postmenopausal women.

Synchrotron- and focal plane array-based Fourier-transform infrared spectroscopy differentiates the basalis and functionalis epithelial endometrial regions and identifies putative stem cell regions of human endometrial glands

The cyclical process of regeneration of the endometrium suggests that it may contain a cell population that can provide daughter cells with high proliferative potential. These cell lineages are clinically significant as they may represent clonogenic cells that may also be involved in tumourigenesis as well as endometriotic lesion development. To determine whether the putative stem cell location within human uterine tissue can be derived using vibrational spectroscopy techniques, normal endometrial tissue was interrogated by two spectroscopic techniques. Paraffin-embedded uterine tissues containing endometrial glands were sectioned to 10-μm-thick parallel tissue sections and were floated onto BaF₂ slides for synchrotron radiation-based Fourier-transform infrared (SR-FTIR) microspectroscopy and globar focal plane array-based FTIR spectroscopy. Different spectral characteristics were identified depending on the location of the glands examined. The resulting infrared spectra were subjected to multivariate analysis to determine associated biophysical differences along the length of longitudinal and crosscut gland sections. Comparison of the epithelial cellular layer of transverse gland sections revealed alterations indicating the presence of putative transient-amplifying-like cells in the basalis and mitotic cells in the functionalis. SR-FTIR microspectroscopy of the base of the endometrial glands identified the location where putative stem cells may reside at the same time pointing towards ν_sPO₂⁻ in DNA and RNA, nucleic acids and amide I and II vibrations as major discriminating factors. This study supports the view that vibration spectroscopy technologies are a powerful adjunct to our understanding of the stem cell biology of endometrial tissue.

Graphical abstract

Associations between endothelial progenitor cells, clinical characteristics and coronary restenosis in patients undergoing percutaneous coronary artery intervention

Objective

Endothelial progenitor cells (EPCs) are produced in the bone marrow and mobilized to the peripheral blood playing a key role in endothelial repair. The objective of this study was to evaluate circulating EPC before and after percutaneous coronary intervention (PCI) with stent implantation and their associations with coronary restenosis and adverse cardiovascular events. Venous blood was obtained before and the day after PCI. Quantification of total white blood count and identification of EPCs (CD45⁻CD34⁺CD31⁺CD133/2⁺CD309⁺) through immunophenotyping by flow cytometry was performed. The primary outcome was either restenosis detected by new coronary angiography or angina with myocardial ischemia at the territory of the stented coronary artery. Secondary outcomes were angina without demonstrable myocardial ischemia, acute coronary syndrome or all-cause death.

Results

37 patients were followed for 1 year. The median EPC count before PCI was 320 cells/mcl and after PCI 286 cells/mcl. A decrease of EPC count was found in 65% of the patients, while 35% displayed an increase. Primary outcomes occurred in 10.8% and the secondary in 37.8% of the patients. Despite a higher level of EPC before (402 cell/mcl) and after PCI (383 cell/mcl) in patients with the secondary outcomes, there was no significant association between EPC and cardiovascular events.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3401-y) contains supplementary material, which is available to authorized users.

17β-Estradiol Promotes Angiogenesis of Rat Cardiac Microvascular Endothelial Cells In Vitro

Background

The formation of new blood vessels, known as angiogenesis, is critical for recovery from ischemic heart disease, and estrogen is considered an important factor in this process. Here, we investigated the effects of 17β-estradiol (17β-E₂) on proliferation and migration of cardiac microvascular endothelial cells (CMECs) in vitro.

Material/Methods

Rat CMECs were isolated and cultured with 17β-E2 (0.001–1 μmol/l) in the absence or presence of the estrogen antagonist tamoxifen. Then, the expression level of estrogen receptor alpha was evaluated by using immunofluorescence assay, RT-PCR, and Western blot. Cell proliferation was detected by methyl thiazolyl tetrazolium analysis and the cell migration was verified by a scraping assay and quantified by a Transwell chamber assay. CMEC differentiation was examined using a tube formation assay. Vascular endothelial growth factor (VEGF) secretion was detected by enzyme-linked immunosorbent assay.

Results

CMECs exhibited homogenous, polygonal, exhibited contact inhibition, and had characteristically ovoid nuclei with 1 or 2 nucleoli, and the cytoplasm exhibited red fluorescence after staining for von Willebrand factor. 17β-E2 treatment upregulated estrogen receptor alpha expression in CMECs. 17β-E2 treatment significantly promoted the proliferation, migration, tubular structure formation, and VEGF secretion in CMECs. The maximal proliferation occurred in the presence of 0.01 μmol/l 17β-E2. Furthermore, estrogen and VEGF were found to synergistically stimulate angiogenesis.

Conclusions

Our data show that 17β-E2 promotes angiogenesis in vitro and suggests that estrogen treatment as a novel therapeutic modality in the management of arterial insufficiency.

Imbalance between endothelial damage and repair capacity in chronic obstructive pulmonary disease

Background

Circulating endothelial microparticles (EMPs) and progenitor cells (PCs) are biological markers of endothelial function and endogenous repair capacity. The study was aimed to investigate whether COPD patients have an imbalance between EMPs to PCs compared to controls and to evaluate the effect of cigarette smoke on these circulating markers.

Methods

Circulating EMPs and PCs were determined by flow cytometry in 27 nonsmokers, 20 smokers and 61 COPD patients with moderate to severe airflow obstruction. We compared total EMPs (CD31⁺CD42b^-), apoptotic if they co-expressed Annexin-V⁺ or activated if they co-expressed CD62E⁺, circulating PCs (CD34⁺CD133⁺CD45⁺) and the EMPs/PCs ratio between groups.

Results

COPD patients presented increased levels of total and apoptotic circulating EMPs, and an increased EMPs/PCs ratio, compared with nonsmokers. Women had less circulating PCs than men through all groups and those with COPD showed lower levels of PCs than both control groups. In smokers, circulating EMPs and PCs did not differ from nonsmokers, being the EMPs/PCs ratio in an intermediate position between COPD and nonsmokers.

Conclusions

We conclude that COPD patients present an imbalance between endothelial damage and repair capacity that might explain the frequent concurrence of cardiovascular disorders. Factors related to the disease itself and gender, rather than cigarette smoking, may account for this imbalance.

Noninvasive evaluation of the migration effect of transplanted endothelial progenitor cells in ischemic muscle using a multimodal imaging agent

Background

Endothelial progenitor cells (EPCs) play an important role in repairing ischemia tissues. However, the survival, migration and therapeutic efficacy of EPCs after transplantation need to be better understood for further cell therapy.

Purpose

This study investigated the migration effect of EPCs labeled with a multimodal imaging agent in a murine ischemic hindlimb model, using magnetic resonance imaging (MRI) and optical imaging after transplantation.

Methods

EPCs derived from mouse bone marrow were labeled with a multimodal imaging agent and were administered through intracardiac delivery to mice with ischemic hindlimbs. The injected EPCs and their migration effect were observed via MRI and optical imaging in vivo, and then compared to a reference standard based on histological data. The quantification of gadolinium in tissue samples was done using inductively coupled plasma mass spectrometry (ICP-MS).

Results

Using in vivo MRI and optical imaging, the labeled EPCs were observed to migrate to ischemic muscle on days 3-5 after injection, while ex vivo, the EPCs were observed in the capillary vessels of the injured tissue. There were significant linear correlations between the Gd contents measured using ICP-MS in samples from the ischemic hindlimbs and livers and T₁ relaxation times calculated using MRI, as well as the average fluorescence signal intensities recorded in optical images (T₁ relaxation time: r=0.491; average signal from optical imaging: r=0.704, P<0.01). EPC treatment upregulated the levels of C-X-C chemokine receptor 4 and vascular endothelial growth factor (VEGF) receptor 2 and enhanced the expression of stromal cell-derived factor-1 and VEGF.

Conclusion

Transplanted EPCs can be monitored with noninvasive MRI and optical imaging in vivo and were found to enhance the paracrine secretion of angiogenic factors.

Basic mechanisms of vascularization in endometriosis and their clinical implications

BACKGROUND

Vascularization is a major hallmark in the pathogenesis of endometriosis. An increasing number of studies suggests that multiple mechanisms contribute to the vascularization of endometriotic lesions, including angiogenesis, vasculogenesis and inosculation.

OBJECTIVE AND RATIONALE

In this review, we provide an overview of the basic mechanisms of vascularization in endometriosis and give special emphasis on their future clinical implications in the diagnosis and therapy of the disease.

SEARCH METHODS

Literature searches were performed in PubMed for English articles with the key words 'endometriosis', 'endometriotic lesions', 'angiogenesis', 'vascularization', 'vasculogenesis', 'endothelial progenitor cells' and 'inosculation'. The searches included both animal and human studies. No restriction was set for the publication date.

OUTCOMES

The engraftment of endometriotic lesions is typically associated with angiogenesis, i.e. the formation of new blood vessels from pre-existing ones. This angiogenic process underlies the complex regulation by angiogenic growth factors and hormones, which activate intracellular pathways and associated signaling molecules. In addition, circulating endothelial progenitor cells (EPCs) are mobilized from the bone marrow and recruited into endometriotic lesions, where they are incorporated into the endothelium of newly developing microvessels, referred to as vasculogenesis. Finally, preformed microvessels in shed endometrial fragments inosculate with the surrounding host microvasculature, resulting in a rapid blood supply to the ectopic tissue. These vascularization modes offer different possibilities for the establishment of novel diagnostic and therapeutic approaches. Angiogenic growth factors and EPCs may serve as biomarkers for the diagnosis and classification of endometriosis. Blood vessel formation and mature microvessels in endometriotic lesions may be targeted by means of anti-angiogenic compounds and vascular-disrupting agents.

WIDER IMPLICATIONS

The establishment of vascularization-based approaches in the management of endometriosis still represents a major challenge. For diagnostic purposes, reliable angiogenic and vasculogenic biomarker panels exhibiting a high sensitivity and specificity must be identified. For therapeutic purposes, novel compounds selectively targeting the vascularization of endometriotic lesions without inducing severe side effects are required. Recent progress in the field of endometriosis research indicates that these goals may be achieved in the near future.

Sex Differences in Circulating Progenitor Cells

BACKGROUND

Lower levels of circulating progenitor cells (PCs) reflect impaired endogenous regenerative capacity and are associated with aging, vascular disease, and poor outcomes. Whether biologic sex and sex hormones influence PC numbers remains a subject of controversy. We sought to determine sex differences in circulating PCs in both healthy persons and patients with coronary artery disease, and to determine their association with sex hormone levels.

METHODS AND RESULTS

In 642 participants (mean age 48 years, 69% women, 23% black) free from cardiovascular disease, we measured circulating PC counts as CD45med+ mononuclear cells coexpressing CD34 and its subsets expressing CD133, chemokine (C-X-C motif) receptor 4, and vascular endothelial growth factor receptor 2 epitopes using flow cytometry. Testosterone and estradiol levels were measured. After adjustment for age, cardiovascular risk factors, and body mass, CD34+ (β=-23%, P<0.001), CD34+/CD133+ (β=-20%, P=0.001), CD34+/chemokine (C-X-C motif) receptor 4-positive (β=-24%, P<0.001), and CD34+/chemokine (C-X-C motif) receptor 4-positive/CD133+ (β=-21%, P=0.001) PC counts, but not vascular endothelial growth factor receptor 2-positive PC counts were lower in women compared with men. Estradiol levels positively correlated with hematopoietic, but not vascular endothelial growth factor receptor 2- positive PC counts in women (P<0.05). Testosterone levels and PC counts were not correlated in men. These findings were replicated in an independent cohort with prevalent coronary artery disease.

CONCLUSIONS

Women have lower circulating hematopoietic PC levels compared with men. Estrogen levels are modestly associated with PC levels in women. Since PCs are reflective of endogenous regenerative capacity, these findings may at least partly explain the rise in adverse cardiovascular events in women with aging and menopause.

Stem cell-based peripheral vascular regeneration

Chronic critical limb ischemia (CLI) represents an end-stage manifestation of peripheral arterial disease (PAD). CLI patients are at very high risk of amputation and cardiovascular complications, leading to severe morbidity and mortality. Because many patients with CLI are ineligible for conventional revascularization procedures, it is urgently needed to explore alternative strategies to improve blood supply in the ischemic tissue. Although researchers initially focused on gene/protein therapy using proangiogenic growth factors/cytokines, recent discovery of somatic stem/progenitor cells including bone marrow (BM)-derived endothelial progenitor cells (EPCs) and mesenchymal stem cells (MSCs) has drastically developed the field of therapeutic angiogenesis for CLI. Overall, early phase clinical trials demonstrated that stem/progenitor cell therapies may be safe, feasible and potentially effective. However, only few late-phase clinical trials have been conducted. This review provides an overview of the preclinical and clinical reports to demonstrate the usefulness and the current limitations of the cell-based therapies.

Endothelial progenitor cells: Exploring the pleiotropic effects of statins

Statins have become a cornerstone of risk modification for ischaemic heart disease patients. A number of studies have shown that they are effective and safe. However studies have observed an early benefit in terms of a reduction in recurrent infarct and or death after a myocardial infarction, prior to any significant change in lipid profile. Therefore, pleiotropic mechanisms, other than lowering lipid profile alone, must account for this effect. One such proposed pleiotropic mechanism is the ability of statins to augment both number and function of endothelial progenitor cells. The ability to augment repair and maintenance of a functioning endothelium may have profound beneficial effect on vascular repair and potentially a positive impact on clinical outcomes in patients with cardiovascular disease. The following literature review will discuss issues surrounding endothelial progenitor cell (EPC) identification, role in vascular repair, factors affecting EPC numbers, the role of statins in current medical practice and their effects on EPC number.

High Levels of Circulating Endothelial Progenitor Cells Are Associated with Acrotism in Patients with Takayasu Arteritis

OBJECTIVES

To investigate the association between endothelial progenitor cells (EPCs) and Takayasu arteritis (TA). Subjects andMethods: A total of 39 subjects were included in this study: 12 subjects had been diagnosed with active TA, 11 had active Behçet disease (BD), and 16 were healthy controls. The EPCs, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels of all the subjects were measured. MedCalc 15.8 software (MedCalc, Belgium) was used for all statistical analyses.

RESULTS

The level of EPCs was higher in TA patients (4.25 ± 2.56) than in the BD group (2.27 ± 2.0) and the healthy controls (2.12 ± 1.2) (p = 0.015). TA patients with acrotism (n = 4) had higher levels of EPCs compared to TA patients without acrotism (n = 8) (6.50 ± 1.73 vs. 3.12 ± 2.16, p = 0.02). A positive correlation was found between EPCs and the ESR (r = 0.723, p = 0.0079) and between EPCs and CRP in patients with TA (r = 0.769, p < 0.0034).

CONCLUSION

High levels of circulating EPCs were correlated with the CRP level and the ESR in patients with TA. These cells could be a marker for acrotism and inflammation in patients with TA.

Jagged-1 Signaling in the Bone Marrow Microenvironment Promotes Endothelial Progenitor Cell Expansion and Commitment of CD133+ Human Cord Blood Cells for Postnatal Vasculogenesis

Notch signaling is involved in cell fate decisions during murine vascular development and hematopoiesis in the microenvironment of bone marrow. To investigate the close relationship between hematopoietic stem cells and human endothelial progenitor cells (EPCs) in the bone marrow niche, we examined the effects of Notch signals [Jagged-1 and Delta-like ligand (Dll)-1] on the proliferation and differentiation of human CD133+ cell-derived EPCs. We established stromal systems using HESS-5 murine bone marrow cells transfected with human Jagged-1 (hJagged-1) or human Dll-1 (hDll-1). CD133+ cord blood cells were co-cultured with the stromal cells for 7 days, and then their proliferation, differentiation, and EPC colony formation was evaluated. We found that hJagged-1 induced the proliferation and differentiation of CD133+ cord blood EPCs. In contrast, hDll-1 had little effect. CD133+ cells stimulated by hJagged-1 differentiated into CD31+/KDR+ cells, expressed vascular endothelial growth factor-A, and showed enhanced EPC colony formation compared with CD133+ cells stimulated by hDll-1. To evaluate the angiogenic properties of hJagged-1- and hDll-1-stimulated EPCs in vivo, we transplanted these cells into the ischemic hindlimbs of nude mice. Transplantation of EPCs stimulated by hJagged-1, but not hDll-1, increased regional blood flow and capillary density in ischemic hindlimb muscles. This is the first study to show that human Notch signaling influences EPC proliferation and differentiation in the bone marrow microenvironment. Human Jagged-1 induced the proliferation and differentiation of CD133+ cord blood progenitors compared with hDll-1. Thus, hJagged-1 signaling in the bone marrow niche may be used to expand EPCs for therapeutic angiogenesis.

Regulatory roles of interferon-inducible protein 204 on differentiation and vasculogenic activity of endothelial progenitor cells

BACKGROUND

Endothelial progenitor cells (EPCs) have shown great potential in angiogenesis either by their differentiation into endothelial cells or by secretion of angiogenic factors. Interferon-inducible protein 204 (Ifi204) has been reported to participate in the regulation of cell growth and differentiation. However, its role in differentiation of EPCs remains unknown. We proposed that Ifi204 could modulate the differentiation and regenerative abilities of EPCs.

METHODS

Ifi204-expressing lentivirus and Ifi204 siRNA were introduced into EPCs to overexpress and suppress the expression of Ifi204. Using fluorescence-activated cell sorting, immunocytochemistry, and quantitative PCR, endothelial markers including CD31, VE-cadherin, and vWF were detected in the modified EPCs. An in-vitro incorporation assay and a colony-forming assay were also performed.

RESULTS

Evidence showed that Ifi204 inhibition decreased the endothelial differentiation and vasculogenic activities of EPCs in vitro. In mice with hindlimb ischemia, downregulation of Ifi204 in EPCs, which was tracked by our newly synthesized nanofluorogen, impaired neovascularization, with a corresponding reduction in hindlimb blood reperfusion by postoperative day 14.

CONCLUSIONS

Ifi204 is required for EPC differentiation and neovascularization in vitro and in vivo. The regulatory roles of Ifi204 in EPC differentiation may benefit the clinical therapy of ischemic vascular diseases.

Bone Marrow-Derived Endothelial Progenitor Cells Reduce Recurrent Miscarriage in Gestation

Bone marrow-derived endothelial progenitor cells (EPCs) have been shown to contribute to not only angiogenesis in ischemic tissue but also neovascularization in uterine endometrium formation. Reduced neovascularization and elevation of serum soluble Flt1, a functional blockage of VEGF, in the development of placenta is thought to be one of the major causes of repeated miscarriages in gestation. We then examined whether transfusion of VEGF-expressing extrinsic EPCs prevented frequent miscarriage via its promotional effect on neovascularization with a VEGFeNOS signaling pathway in a mouse miscarriage model. The results showed that systemic EPC transfusion significantly reduced the rate of miscarriage, and EPCs were frequently observed in the miscarriage placenta. In contrast, only a few EPCs were detected in the placenta of normal gestation. The vascular pattern was irregular, and vessel size was small in the miscarriage placenta compared with that of normal gestation. The placental vascular pattern in miscarriage tended to be normalized with increased vessel size up to a similar level as normal gestation by EPC recruitment. For the mechanistic insight, since soluble Flt1 inhibits EPC functions, it was suggested that the increased soluble Flt1 could suppress the recruited EPC functional activity in the miscarriage placenta. In vitro experiments by soluble Flt1 treatment in cultured EPCs suggested that the vascular abnormality could be partly due to the inhibition of eNOS expression by the increased amounts of soluble Flt1. These findings from animal experiments indicated that autologous EPC therapy may be a novel therapy to prevent miscarriage in high-risk pregnancies, such as preeclampsia.

Estrogen Stimulates Homing of Endothelial Progenitor Cells to Endometriotic Lesions

The incorporation of endothelial progenitor cells (EPCs) into microvessels contributes to the vascularization of endometriotic lesions. Herein, we analyzed whether this vasculogenic process is regulated by estrogen. Estrogen- and vehicle-treated human EPCs were analyzed for migration and tube formation. Endometriotic lesions were induced in irradiated FVB/N mice, which were reconstituted with bone marrow from FVB/N-TgN (Tie2/green fluorescent protein) 287 Sato mice. The animals were treated with 100 μg/kg β-estradiol 17-valerate or vehicle (control) over 7 and 28 days. Lesion growth, cyst formation, homing of green fluorescent protein(+)/Tie2(+) EPCs, vascularization, cell proliferation, and apoptosis were analyzed by high-resolution ultrasonography, caliper measurements, histology, and immunohistochemistry. Numbers of blood circulating EPCs were assessed by flow cytometry. In vitro, estrogen-treated EPCs exhibited a higher migratory and tube-forming capacity when compared with controls. In vivo, numbers of circulating EPCs were not affected by estrogen. However, estrogen significantly increased the number of EPCs incorporated into the lesions' microvasculature, resulting in an improved early vascularization. Estrogen further stimulated the growth of lesions, which exhibited massively dilated glands with a flattened layer of stroma. This was mainly because of an increased glandular secretory activity, whereas cell proliferation and apoptosis were not markedly affected. These findings indicate that vasculogenesis in endometriotic lesions is dependent on estrogen, which adds a novel hormonally regulated mechanism to the complex pathophysiology of endometriosis.

Low-dose estradiol and endothelial and inflammatory biomarkers in menopausal overweight/obese women

OBJECTIVE

We aimed to investigate the effects of low-dose transdermal estrogen on endothelial and inflammatory biomarkers in menopausal overweight/obese women.

METHODS

We recruited 44 menopausal women (47-55 years; body mass index 27.5-34.9 kg/m(2)) and divided them into estradiol (1 mg/day; n = 22) or placebo groups (n = 22). They were double-blinded, followed and treated for 3 months. At baseline and post-intervention, inflammatory biomarkers (hs-CRP, IL-1β, IL-6, MCP-1 and TNF-α) and of vascular injury (activated circulating endothelial cells, CEC-a) and repair (endothelial progenitor cells, EPC) were quantified. Resting CECs (CEC-r) were also assessed. Microvascular reactivity and vasomotion were analyzed by laser-Doppler flowmetry.

RESULTS

Volunteers (51.8 ± 2.3 years; mean body mass index 31.5 ± 2.5 kg/m(2)) had been menopausal for 3 (range 2-5) years. After treatment, no changes were observed in the placebo group, while levels of CEC-r and EPC increased in the estradiol group. In this group, no changes in inflammatory biomarkers were observed but it required a lower cumulative dose of acetylcholine to achieve peak velocity during endothelial-dependent vasodilatation and there was increased endothelial-independent vasodilatation.

CONCLUSIONS

The short-term use of low-dose transdermal estradiol therapy in overweight/obese menopausal women increased markers of vascular repair and improved microvascular reactivity without changing the inflammatory biomarkers.

CLINICAL TRIAL REGISTRATION

NCT01295892 at www.clinicaltrials.gov .

Sexual dimorphism in cancer

The incidence of many types of cancer arising in organs with non-reproductive functions is significantly higher in male populations than in female populations, with associated differences in survival. Occupational and/or behavioural factors are well-known underlying determinants. However, cellular and molecular differences between the two sexes are also likely to be important. In this Opinion article, we focus on the complex interplay that sex hormones and sex chromosomes can have in intrinsic control of cancer-initiating cell populations, the tumour microenvironment and systemic determinants of cancer development, such as the immune system and metabolism. A better appreciation of these differences between the two sexes could be of substantial value for cancer prevention as well as treatment.

Recent Progress in Endothelial Progenitor Cell Culture Systems: Potential for Stroke Therapy

Endothelial progenitor cells (EPCs) participate in endothelial repair and angiogenesis due to their abilities to differentiate into endothelial cells and to secrete protective cytokines and growth factors. Consequently, there is considerable interest in cell therapy with EPCs isolated from peripheral blood to treat various ischemic injuries. Quality and quantity-controlled culture systems to obtain mononuclear cells enriched in EPCs with well-defined angiogenic and anti-inflammatory phenotypes have recently been developed, and increasing evidence from animal models and clinical trials supports the idea that transplantation of EPCs contributes to the regenerative process in ischemic organs and is effective for the therapy of ischemic cerebral injury. Here, we briefly describe the general characteristics of EPCs, and we review recent developments in culture systems and applications of EPCs and EPC-enriched cell populations to treat ischemic stroke.

Pathological Left Ventricular Hypertrophy and Stem Cells: Current Evidence and New Perspectives

Left ventricular hypertrophy (LVH) is a strong predictor of adverse cardiovascular outcomes. It is the result of complex mechanisms that include not only an increase in protein synthesis and cell size but also proliferating cardiac progenitor cells and the influx of bone marrow-derived cells developing into cardiomyocytes. Stem and progenitor cells are known to contribute to the renewal of adult mammalian cardiomyocytes in case of myocardial injury or pressure and volume overload. They are activated in LVH and play a regulatory role in myocardial repair. They have high proliferative potential and secrete numerous cytokines, growth factors, and microRNAs that play important roles in cell differentiation, cardiac remodeling, and neovascularization. They are mobilized in response to either mechanical or chemical stimuli, hormones, or pharmacologic agents. Another important source of progenitor cells is the epicardial layer. It appears that precursor cells migrate from the epicardium to the myocardium in order to interact with myocardial cells. In addition, migratory cells participate in the formation of almost all cardiac structures in myocardial hypertrophy. Although the pathophysiological mechanisms are still obscure and further studies are required, their properties may open the door to regenerative cell therapy for the prevention of adverse remodeling.

Endometrial stem/progenitor cells: the first 10 years

BACKGROUND

The existence of stem/progenitor cells in the endometrium was postulated many years ago, but the first functional evidence was only published in 2004. The identification of rare epithelial and stromal populations of clonogenic cells in human endometrium has opened an active area of research on endometrial stem/progenitor cells in the subsequent 10 years.

METHODS

The published literature was searched using the PubMed database with the search terms ‘endometrial stem cells and menstrual blood stem cells' until December 2014.

RESULTS

Endometrial epithelial stem/progenitor cells have been identified as clonogenic cells in human and as label-retaining or CD44⁺ cells in mouse endometrium, but their characterization has been modest. In contrast, endometrial mesenchymal stem/stromal cells (MSCs) have been well characterized and show similar properties to bone marrow MSCs. Specific markers for their enrichment have been identified, CD146⁺PDGFRβ⁺ (platelet-derived growth factor receptor beta) and SUSD2⁺ (sushi domain containing-2), which detected their perivascular location and likely pericyte identity in endometrial basalis and functionalis vessels. Transcriptomics and secretomics of SUSD2⁺ cells confirm their perivascular phenotype. Stromal fibroblasts cultured from endometrial tissue or menstrual blood also have some MSC characteristics and demonstrate broad multilineage differentiation potential for mesodermal, endodermal and ectodermal lineages, indicating their plasticity. Side population (SP) cells are a mixed population, although predominantly vascular cells, which exhibit adult stem cell properties, including tissue reconstitution. There is some evidence that bone marrow cells contribute a small population of endometrial epithelial and stromal cells. The discovery of specific markers for endometrial stem/progenitor cells has enabled the examination of their role in endometrial proliferative disorders, including endometriosis, adenomyosis and Asherman's syndrome. Endometrial MSCs (eMSCs) and menstrual blood stromal fibroblasts are an attractive source of MSCs for regenerative medicine because of their relative ease of acquisition with minimal morbidity. Their homologous and non-homologous use as autologous and allogeneic cells for therapeutic purposes is currently being assessed in preclinical animal models of pelvic organ prolapse and phase I/II clinical trials for cardiac failure. eMSCs and stromal fibroblasts also exhibit non-stem cell-associated immunomodulatory and anti-inflammatory properties, further emphasizing their desirable properties for cell-based therapies.

CONCLUSIONS

Much has been learnt about endometrial stem/progenitor cells in the 10 years since their discovery, although several unresolved issues remain. These include rationalizing the terminology and diagnostic characteristics used for distinguishing perivascular stem/progenitor cells from stromal fibroblasts, which also have considerable differentiation potential. The hierarchical relationship between clonogenic epithelial progenitor cells, endometrial and decidual SP cells, CD146⁺PDGFR-β⁺ and SUSD2⁺ cells and menstrual blood stromal fibroblasts still needs to be resolved. Developing more genetic animal models for investigating the role of endometrial stem/progenitor cells in endometrial disorders is required, as well as elucidating which bone marrow cells contribute to endometrial tissue. Deep sequencing and epigenetic profiling of enriched populations of endometrial stem/progenitor cells and their differentiated progeny at the population and single-cell level will shed new light on the regulation and function of endometrial stem/progenitor cells.

Endometrial side population cells: potential adult stem/progenitor cells in endometrium

Uterine endometrium is one of the most important organs for species preservation. However, the physiology of human endometrium remains poorly understood, because the human endometrium undergoes rapid and large changes during each menstrual cycle and it is very difficult to investigate human endometrium as one organ. This remarkable regenerative capacity of human endometrium strongly suggests the existence of adult stem cells, and physiology of endometrium cannot be explained without adult stem cells. Therefore, investigating endometrial stem/progenitor cells should lead to a breakthrough in understanding the normal endometrial physiology and the pathophysiology of endometrial neoplastic disorders, such as endometriosis and endometrial cancer. Several cell populations have been discovered as putative endometrial stem/progenitor cells. Emerging evidence reveals that the endometrial side population (SP) is one of the potential endometrial stem/progenitor populations. Of all the endometrial stem/progenitor cell candidates, the endometrial SP (ESP) is best investigated in vitro and in vivo, and has the largest number of references. In this review, we provide an overview of the accumulating evidence for the ESP cells, both directly from human endometria and from cultured endometrial cells. Furthermore, SP cells are compared to other potential stem/progenitor cells, and we discuss their stem cell properties. We also discuss the difficulties and unsolved issues in endometrial stem cell biology.

Chronic endurance exercise affects paracrine action of CD31+ and CD34+ cells on endothelial tube formation

We aimed to determine if chronic endurance-exercise habits affected redox status and paracrine function of CD34(+) and CD34(-)/CD31(+) circulating angiogenic cells (CACs). Subjects were healthy, nonsmoking men and women aged 18-35 yr and categorized by chronic physical activity habits. Blood was drawn from each subject for isolation and culture of CD34(+) and CD34(-)/CD31(+) CACs. No differences in redox status were found in any group across either cell type. Conditioned media (CM) was generated from the cultured CACs and used in an in vitro human umbilical vein endothelial cell-based tube assay. CM from CD34(+) cells from inactive individuals resulted in tube structures that were 29% shorter in length (P < 0.05) and 45% less complex (P < 0.05) than the endurance-trained group. CD34(-)/CD31(+) CM from inactive subjects resulted in tube structures that were 26% shorter in length (P < 0.05) and 42% less complex (P < 0.05) than endurance-trained individuals. Proteomics analyses identified S100A8 and S100A9 in the CM. S100A9 levels were 103% higher (P < 0.05) and S100A8 was 97% higher in the CD34(-)/CD31(+) CM of inactive subjects compared with their endurance-trained counterparts with no significant differences in either protein in the CM of CD34(+) CACs as a function of training status. Recombinant S100A8/A9 treatment at concentrations detected in inactive subjects' CD34(-)/CD31(+) CAC CM also reduced tube formation (P < 0.05). These findings are the first, to our knowledge, to demonstrate a differential paracrine role in CD34(+) and CD34(-)/CD31(+) CACs on tube formation as a function of chronic physical activity habits and identifies a differential secretion of S100A9 by CD34(-)/CD31(+) CACs due to habitual exercise.

The real face of endothelial progenitor cells - Circulating angiogenic cells as endothelial prognostic marker?

Endothelial progenitor cells (EPCs) have been extensively studied for almost 19 years now and were considered as a potential marker for endothelial regeneration ability. On the other hand, circulating endothelial cells (CEC) were studied as biomarker for endothelial injury. Yet, in the literature, there is also huge incoherency in regards to terminology and protocols used. This results in misleading conclusions on the role of so called "EPCs", especially in the clinical field. The discrepancies are mainly due to strong phenotypic overlap between EPCs and circulating angiogenic cells (CAC), therefore changes in "EPC" terminology have been suggested. Other factors leading to inconsistent results are varied definitions of the studied populations and the lack of universal data reporting, which could strongly affect data interpretation. The current review is focused on controversies concerning the use of "EPCs"/CAC and CEC as putative endothelial diagnostic markers.

Progress and prospects of endothelial progenitor cell therapy in coronary stent implantation

Drug-eluting stents (DES) have been widely used to treat coronary artery disease (CAD) since their clinical use has significantly reduced the occurrence of in-stent restenosis (ISR) as compared with the initially applied bare-metal stents (BMS). However, analyses of long-term clinical outcome have raised concerns about the serious safety problem of DES, such as ISR caused by late or very late thrombosis. Various studies showed that those complications were associated with vascular endothelial injury/dysfunction or endothelialization delaying. Recently, through biological characterization of endothelial progenitor cells (EPCs), mechanistic understanding of rapid re-endothelialization of the vascular injury sites after coronary stenting has become possible and is a new research hotspot in the prevention of ISR and late/very late stent thrombosis. It has been well recognized that the formation of a functional endothelial layer from EPCs requires a coordinated sequence of multistep and signaling events, which includes cell mobilization, adhesion, migration and finally the differentiation to vascular endothelial cells (VECs). In this review, we summarize and discuss the currently relevant information about EPCs, the mechanism of DES interfering with the natural vascular healing process in preventing or delaying the formation of a functional endothelial layer, and EPCs-mediated acceleration of re-endothelialization at vascular injury sites. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1237-1247, 2016.