Impairment of human cell-based vasculogenesis in rats by hypercholesterolemia-induced endothelial dysfunction and rescue with L-arginine supplementation

Racial Differences in Mental Stress-Induced Transient Endothelial Dysfunction and Its Association With Cardiovascular Outcomes

OBJECTIVE

This study aimed to investigate differences in transient endothelial dysfunction (TED) with mental stress in Black and non-Black individuals with coronary heart disease (CHD), and their potential impact on cardiovascular outcomes.

METHODS

We examined 812 patients with stable CHD between June 2011 and March 2016 and followed through February 2020 at a university-affiliated hospital network. Flow-mediated vasodilation (FMD) was assessed before and 30 minutes after mental stress. TED was defined as a lower poststress FMD than prestress FMD. We compared prestress FMD, post-stress FMD, and TED between Black and non-Black participants. In both groups, we examined the association of TED with an adjudicated composite end point of cardiovascular death or nonfatal myocardial infarction (first and recurring events) after adjusting for demographic, clinical, and socioeconomic factors.

RESULTS

Prestress FMD was lower in Black than non-Black participants (3.7 [2.8] versus 4.9 [3.8], p < .001) and significantly declined with mental stress in both groups. TED occurred more often in Black (76%) than non-Black patients (67%; multivariable-adjusted odds ratio = 1.6, 95% confidence interval = 1.5-1.7). Over a median (interquartile range) follow-up period of 75 (65-82) months, 142 (18%) patients experienced either cardiovascular death or nonfatal myocardial infarction. Black participants had a 41.9% higher risk of the study outcome than non-Black participants (95% confidence interval = 1.01-1.95). TED with mental stress explained 69% of this excess risk.

CONCLUSIONS

Among CHD patients, Black individuals are more likely than non-Black individuals to develop endothelial dysfunction with mental stress, which in turn explains a substantial portion of their excess risk of adverse events.

Characterization of maternal plasma biomarkers associated with delivery of small and large for gestational age infants in the MIREC study cohort

Objective

Neonatal morbidity and mortality can be influenced by maternal health status. Information on maternal and fetal biomarkers of adverse health outcomes is limited. This work aims at identifying maternal biomarkers associated with low and high birth weight for gestational age groups.

Design and settings

Population-based prospective cohort study of the potential adverse health effects of exposure to environmental contaminants on pregnancy and infant health.

Methods

Third trimester maternal plasma samples (n = 1588) from a pregnancy cohort (Maternal-Infant Research on Environmental Chemicals Study, MIREC) were analyzed for changes in a target spectrum of biomarkers of vascular health (e.g., matrix metalloproteinases MMPs, vascular endothelial cell growth factor VEGF), inflammation (e.g. cellular adhesion molecules CAMs, cytokines, chemokines) by affinity-based multiplex protein array analyses. Multivariate logistic regression analyses were done to examine associations between target plasma biomarkers, maternal-infant characteristics, and birth weight outcomes assessed as small for gestational age (SGA) ≤10^th percentile and large for gestational age (LGA) ≥90^th percentile groups.

Results and outcomes

Our results revealed that maternal plasma biomarkers monocyte chemoattractant protein-1 MCP-1 (p<0.05, +ve) and VEGF (p<0.05, -ve) along with parity = 1 (p<0.01, -ve) and gestational hypertension (p<0.05, +ve) were associated with SGA births. Meanwhile, LGA was associated with maternal plasma VEGF (p<0.05, +ve) and MMP-9 (p<0.05, -ve) and gestational hypertension (p<0.01, +ve), pre-pregnancy body mass index (p<0.01, +ve), parity (p<0.05, +ve) and education (p<0.05, -ve).

Conclusions

Third trimester maternal plasma biomarkers in combination with maternal health and socioeconomic characteristics can be useful in predicting SGA and LGA outcomes. Maternal vascular health and inflammatory status may contribute to both SGA and LGA births through distinct molecular mechanisms.

Extracellular Vesicle Injection Improves Myocardial Function and Increases Angiogenesis in a Swine Model of Chronic Ischemia

BACKGROUND

Mesenchymal stem cell-derived extracellular vesicles (EVs) are believed to be cardioprotective in myocardial infarct. The objective of this study was to examine the effects of human mesenchymal cell-derived EV injection on cardiac function, myocardial blood flow, and vessel density in the setting of chronic myocardial ischemia.

METHODS AND RESULTS

Twenty-three Yorkshire swine underwent placement of an ameroid constrictor on their left circumflex artery. Two weeks later, the animals were split into 2 groups: the control group (CON; n=7) and the EV myocardial injection group (MVM; n=10). The MVM group underwent myocardial injection of 50 μg of EVs in 2 mL 0.9% saline into the ischemic myocardium. Five weeks later, the pigs underwent a harvest procedure, and the left ventricular myocardium was analyzed. Absolute blood flow and the ischemic/nonischemic myocardial perfusion ratio were increased in the ischemic myocardium in the MVM group compared with the CON group. Pigs in the MVM group had increased capillary and arteriolar density in the ischemic myocardial tissue compared with CON pigs. There was an increase in expression of the phospho-mitogen-activated protein kinase/mitogen-activated protein kinase ratio, the phospho-endothelial nitric oxide synthase/endothelial nitric oxide synthase ratio, and total protein kinase B in the MVM group compared with CON. There was an increase in cardiac output and stroke volume in the MVM group compared with CON.

CONCLUSIONS

In the setting of chronic myocardial ischemia, myocardial injection of human mesenchymal cell-derived EVs increases blood flow to ischemic myocardial tissue by induction of capillary and arteriolar growth via activation of the protein kinase B/endothelial nitric oxide synthase and mitogen-activated protein kinase signaling pathways resulting in increased cardiac output and stroke volume.

Alignment of inducible vascular progenitor cells on a micro-bundle scaffold improves cardiac repair following myocardial infarction

Ischemic heart disease is still the leading cause of death even with the advancement of pharmaceutical therapies and surgical procedures. Early vascularization in the ischemic heart is critical for a better outcome. Although stem cell therapy has great potential for cardiovascular regeneration, the ideal cell type and delivery method of cells have not been resolved. We tested a new approach of stem cell therapy by delivery of induced vascular progenitor cells (iVPCs) grown on polymer micro-bundle scaffolds in a rat model of myocardial infarction. iVPCs partially reprogrammed from vascular endothelial cells (ECs) had potent angiogenic potential and were able to simultaneously differentiate into vascular smooth muscle cells (SMCs) and ECs in 2D culture. Under hypoxic conditions, iVPCs also secreted angiogenic cytokines such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) as measured by enzyme-linked immunosorbent assay (ELISA). A longitudinal micro-scaffold made from poly(lactic-co-glycolic acid) was sufficient for the growth and delivery of iVPCs. Co-cultured ECs and SMCs aligned well on the micro-bundle scaffold similarly as in the vessels. 3D cell/polymer micro-bundles formed by iVPCs and micro-scaffolds were transplanted into the ischemic myocardium in a rat model of myocardial infarction (MI) with ligation of the left anterior descending artery. Our in vivo data showed that iVPCs on the micro-bundle scaffold had higher survival, and better retention and engraftment in the myocardium than free iVPCs. iVPCs on the micro-bundles promoted better cardiomyocyte survival than free iVPCs. Moreover, iVPCs and iVPC/polymer micro-bundles treatment improved cardiac function (ejection fraction and fractional shortening, endocardial systolic volume) measured by echocardiography, increased vessel density, and decreased infarction size [endocardial and epicardial infarct (scar) length] better than untreated controls at 8 weeks after MI. We conclude that iVPCs grown on a polymer micro-bundle scaffold are new promising approach for cell-based therapy designed for cardiovascular regeneration in ischemic heart disease.

Optimizing the host substrate environment for cardiac angiogenesis, arteriogenesis, and myogenesis

INTRODUCTION

The diseased host milieu, such as endothelial dysfunction (ED), decreased NO bioavailability, and ischemic/inflammatory post-MI environment, hamper the clinical success of existing cardiac regenerative therapies. Area covered: In this article, current strategies including pharmacological and nonpharmacological approaches for improving the diseased host milieu are reviewed. Specifically, the authors provide focus on: i) the mechanism of ED in patients with cardiovascular diseases, ii) the current results of ED improving strategies in pre-clinical and clinical studies, and iii) the use of biomaterials as a novel modulator in damaged post-MI environment. Expert opinion: Adjunct therapies which improve host endothelial function have demonstrated promising outcomes, potentially overcoming disappointing results of cell therapy in human studies. In the future, elucidation of the interactions between the host tissue and therapeutic agents, as well as downstream signaling pathways, will be the next challenges in enhancing regenerative therapy. More careful investigations are also required to establish these agents' safety and efficacy for wide usage in humans.

Nitrite anion therapy protects against chronic ischemic tissue injury in db/db diabetic mice in a NO/VEGF-dependent manner

Nitrite anion has been demonstrated to be a prodrug of nitric oxide (NO) with positive effects on tissue ischemia/reperfusion injury, cytoprotection, and vasodilation. However, effects of nitrite anion therapy for ischemic tissue vascular remodeling during diabetes remain unknown. We examined whether sodium nitrite therapy altered ischemic revascularization in BKS-Lepr(db/db) mice subjected to permanent unilateral femoral artery ligation. Sodium nitrite therapy completely restored ischemic hind limb blood flow compared with nitrate or PBS therapy. Importantly, delayed nitrite therapy 5 days after ischemia restored ischemic limb blood flow in aged diabetic mice. Restoration of blood flow was associated with increases in ischemic tissue angiogenesis activity and cell proliferation. Moreover, nitrite but not nitrate therapy significantly prevented ischemia-mediated tissue necrosis in aged mice. Nitrite therapy significantly increased ischemic tissue vascular endothelial growth factor (VEGF) protein expression that was essential for nitrite-mediated reperfusion of ischemic hind limbs. Nitrite significantly increased ischemic tissue NO bioavailability along with concomitant reduction of superoxide formation. Lastly, nitrite treatment also significantly stimulated hypoxic endothelial cell proliferation and migration in the presence of high glucose in an NO/VEGF-dependent manner. These results demonstrate that nitrite therapy effectively stimulates ischemic tissue vascular remodeling in the setting of metabolic dysfunction that may be clinically useful.

Applicability of a high-throughput shotgun plasma protein screening approach in understanding maternal biological pathways relevant to infant birth weight outcome

There are reports linking maternal nutritional status, smoking and environmental chemical exposures to adverse pregnancy outcomes. However, biological bases for association between some of these factors and birth outcomes are yet to be established. The objective of this preliminary work is to test the capability of a new high-throughput shotgun plasma proteomic screening in identifying maternal changes relevant to pregnancy outcome. A subset of third trimester plasma samples (N=12) associated with normal and low-birth weight infants were fractionated, tryptic-digested and analyzed for global proteomic changes using a MALDI-TOF-TOF-MS methodology. Mass spectral data were mined for candidate biomarkers using bioinformatic and statistical tools. Maternal plasma profiles of cytokines (e.g. IL8, TNF-α), chemokines (e.g. MCP-1) and cardiovascular endpoints (e.g. ET-1, MMP-9) were analyzed by a targeted approach using multiplex protein array and HPLC-Fluorescence methods. Target and global plasma proteomic markers were used to identify protein interaction networks and maternal biological pathways relevant to low infant birth weight. Our results exhibited the potential to discriminate specific maternal physiologies relevant to risk of adverse birth outcomes. This proteomic approach can be valuable in understanding the impacts of maternal factors such as environmental contaminant exposures and nutrition on birth outcomes in future work.

BIOLOGICAL SIGNIFICANCE

We demonstrate here the fitness of mass spectrometry-based shot-gun proteomics for surveillance of biological changes in mothers, and for adverse pathway analysis in combination with target biomarker information. This approach has potential for enabling early detection of mothers at risk for low infant birth weight and preterm birth, and thus early intervention for mitigation and prevention of adverse pregnancy outcomes. This article is part of a Special Issue entitled: Can Proteomics Fill the Gap Between Genomics and Phenotypes?

Current status and future perspectives of mass spectrometry imaging

Mass spectrometry imaging is employed for mapping proteins, lipids and metabolites in biological tissues in a morphological context. Although initially developed as a tool for biomarker discovery by imaging the distribution of protein/peptide in tissue sections, the high sensitivity and molecular specificity of this technique have enabled its application to biomolecules, other than proteins, even in cells, latent finger prints and whole organisms. Relatively simple, with no requirement for labelling, homogenization, extraction or reconstitution, the technique has found a variety of applications in molecular biology, pathology, pharmacology and toxicology. By discriminating the spatial distribution of biomolecules in serial sections of tissues, biomarkers of lesions and the biological responses to stressors or diseases can be better understood in the context of structure and function. In this review, we have discussed the advances in the different aspects of mass spectrometry imaging processes, application towards different disciplines and relevance to the field of toxicology.

Myocardial therapeutic angiogenesis: a review of the state of development and future obstacles

A significant percentage of patients have coronary artery disease that is too advanced or diffuse for percutaneous or surgical intervention. Therapeutic angiogenesis is a treatment modality to induce vessel formation that is being developed for patients with advanced coronary disease not amenable to currently available interventions. A number of approaches to induce coronary collateralization are being developed. These include gene, protein, cellular and miRNA modalities, each of which have advantages and disadvantages. At this time, no modality has emerged as the single clear choice, and combination therapies may provide synergistic benefits. However, there have been a number of recent studies advancing our knowledge as to how we can refine procollateralizing treatments. In this article, we will examine some recent successes and future obstacles in the effort to bring therapeutic angiogenesis to patients.

Endothelial dysfunction and diabetes: effects on angiogenesis, vascular remodeling, and wound healing

Diabetes mellitus (DM) is a chronic metabolic disorder characterized by inappropriate hyperglycemia due to lack of or resistance to insulin. Patients with DM are frequently afflicted with ischemic vascular disease or wound healing defect. It is well known that type 2 DM causes amplification of the atherosclerotic process, endothelial cell dysfunction, glycosylation of extracellular matrix proteins, and vascular denervation. These complications ultimately lead to impairment of neovascularization and diabetic wound healing. Therapeutic angiogenesis remains an attractive treatment modality for chronic ischemic disorders including PAD and/or diabetic wound healing. Many experimental studies have identified better approaches for diabetic cardiovascular complications, however, successful clinical translation has been limited possibly due to the narrow therapeutic targets of these agents or the lack of rigorous evaluation of pathology and therapeutic mechanisms in experimental models of disease. This paper discusses the current body of evidence identifying endothelial dysfunction and impaired angiogenesis during diabetes.

Induction of vascular progenitor cells from endothelial cells stimulates coronary collateral growth

RATIONALE

A well-developed coronary collateral circulation improves the morbidity and mortality of patients following an acute coronary occlusion. Although regenerative medicine has great potential in stimulating vascular growth in the heart, to date there have been mixed results, and the ideal cell type for this therapy has not been resolved.

OBJECTIVE

To generate induced vascular progenitor cells (iVPCs) from endothelial cells, which can differentiate into vascular smooth muscle cells (VSMCs) or endothelial cells (ECs), and test their capability to stimulate coronary collateral growth.

METHODS AND RESULTS

We reprogrammed rat ECs with the transcription factors Oct4, Klf4, Sox2, and c-Myc. A population of reprogrammed cells was derived that expressed pluripotent markers Oct4, SSEA-1, Rex1, and AP and hemangioblast markers CD133, Flk1, and c-kit. These cells were designated iVPCs because they remained committed to vascular lineage and could differentiate into vascular ECs and VSMCs in vitro. The iVPCs demonstrated better in vitro angiogenic potential (tube network on 2-dimensional culture, tube formation in growth factor reduced Matrigel) than native ECs. The risk of teratoma formation in iVPCs is also reduced in comparison with fully reprogrammed induced pluripotent stem cells (iPSCs). When iVPCs were implanted into myocardium, they engrafted into blood vessels and increased coronary collateral flow (microspheres) and improved cardiac function (echocardiography) better than iPSCs, mesenchymal stem cells, native ECs, and sham treatments.

CONCLUSIONS

We conclude that iVPCs, generated by partially reprogramming ECs, are an ideal cell type for cell-based therapy designed to stimulate coronary collateral growth.