Circulating microparticles: a potential prognostic marker for atherosclerotic vascular disease

Exosomes based strategies for cardiovascular diseases: Opportunities and challenges

Exosomes, as nanoscale extracellular vesicles (EVs), are secreted by all types of cells to facilitate intercellular communication in living organisms. After being taken up by neighboring or distant cells, exosomes can alter the expression levels of target genes in recipient cells and thereby affect their pathophysiological outcomes depending on payloads encapsulated therein. The functions and mechanisms of exosomes in cardiovascular diseases have attracted much attention in recent years and are thought to have cardioprotective and regenerative potential. This review summarizes the biogenesis and molecular contents of exosomes and details the roles played by exosomes released from various cells in the progression and recovery of cardiovascular disease. The review also discusses the current status of traditional exosomes in cardiovascular tissue engineering and regenerative medicine, pointing out several limitations in their application. It emphasizes that some of the existing emerging industrial or bioengineering technologies are promising to compensate for these shortcomings, and the combined application of exosomes and biomaterials provides an opportunity for mutual enhancement of their performance. The integration of exosome-based cell-free diagnostic and therapeutic options will contribute to the further development of cardiovascular regenerative medicine.

Surface markers on microparticles involved in obesity-derived diseases

AIMS

This review aimed to investigate the different types of microparticles playing role in obesity-related diseases. Additionally, the factors participating in changing the microparticles amount in obese people will also be discussed.

MATERIAL & METHODS

The authors collected the relevant articles published until 2023 and these are carefully selected from three scientific databases based on keywords.

KEY FINDINGS

It has been revealed that exercise might change the microparticle content in the body. The other factor which participates in obesity process is the oxidative stress which is increased in microparticles. Moreover, the obesity is implicated in metabolic conditions including diabetes and cardiovascular diseases.

SIGNIFICANCE

More than one-third of people on the planet today are known as overweight individuals. Microparticles (MPs) are small membrane-bound vesicles that are found in healthy people's blood and are elevated in patients with pathological conditions such as obesity. MPs mostly come from platelets, leukocytes, endothelial cells, and vascular smooth muscle cells. Considering the effect of obesity on microparticles, these small membrane-bound vesicles might play a crucial role in preventing or treatment of obesity.

Selective labeling of phosphatidylserine for cryo-TEM by a two-step immunogold method

Immunogold labeling in transmission electron microscopy (TEM) utilizes the high electron density of gold nanoparticles conjugated to proteins to identify specific antigens in biological samples. In this work we applied the concept of immunogold labeling for the labeling of negatively charged phospholipids, namely phosphatidylserine, by a simple protocol, performed entirely in the liquid-phase, from which cryo-TEM specimens can be directly prepared. Labeling included a two-step process using biotinylated annexin-V and gold-conjugated streptavidin. We initially applied it on liposomal systems, demonstrating its specificity and selectivity, differentiating between 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dioleoyl-sn-glycero-3-phospho-l-serine (DOPS) membranes. We also observed specific labeling on extracellular vesicle samples isolated from THP1 cells and from MDA-468 cells, which underwent stimulations. Finally, we compared the levels of annexin-V labeling on the cells vs. on their isolated EVs by flow cytometry and found a good correlation with the cryo-TEM results. This simple, yet effective labeling technique makes it possible to differentiate between negatively charged and non-negatively charged membranes, thus shillucidating their possible EV shedding mechanism.

Exosome Liberation by Human Neutrophils under L-Amino Acid Oxidase of Calloselasma rhodostoma Venom Action

L-Amino acid oxidase (LAAO) is an enzyme found in snake venom that has multifaceted effects, including the generation of hydrogen peroxide (H2O2) during oxidative reactions, leading to various biological and pharmacological outcomes such as apoptosis, cytotoxicity, modulation of platelet aggregation, hemorrhage, and neutrophil activation. Human neutrophils respond to LAAO by enhancing chemotaxis, and phagocytosis, and releasing reactive oxygen species (ROS) and pro-inflammatory mediators. Exosomes cellular nanovesicles play vital roles in intercellular communication, including immune responses. This study investigates the impact of Calloselasma rhodostoma snake venom-derived LAAO (Cr-LAAO) on human neutrophil exosome release, including activation patterns, exosome formation, and content. Neutrophils isolated from healthy donors were stimulated with Cr-LAAO (100 μg/mL) for 3 h, followed by exosome isolation and analysis. Results show that Cr-LAAO induces the release of exosomes with distinct protein content compared to the negative control. Proteomic analysis reveals proteins related to the regulation of immune responses and blood coagulation. This study uncovers Cr-LAAO's ability to activate human neutrophils, leading to exosome release and facilitating intercellular communication, offering insights into potential therapeutic approaches for inflammatory and immunological disorders.

The increment of annexin V-positive microvesicles versus annexin V-negative microvesicles in CSF of an animal model of Alzheimer's disease

OBJECTIVE

Extracellular microvesicles (MVs) as a specific signaling molecule have received much attention in nervous system studies. Alterations in the tissue redox status in pathological conditions, such as Alzheimer's disease (AD), facilitate the translocation of cell membrane phosphatidylserine to the outer leaflet and lead to the MVs shedding. Annexin V binds with high affinity to phosphatidylserine. Some arguments exist about whether Annexin V-negative MVs should be considered in pathological conditions.

MATERIAL AND METHOD

We compared the kinetics of two phenotypes of Annexin V-positive and Annexin V-negative MVs in the cerebrospinal fluid (CSF) of amyloid-β (Aβ)-treated male Wistar rats with flow cytometry technique. The Aβ was injected bilaterally into the cerebral ventricles. Thioflavin T staining was used to confirm the presence of hippocampal Aβ fibrils two weeks post-Aβ injection. Levels of hippocampal interleukin-1β were assessed as an inflammatory index. The CSF malondialdehyde (MDA) concentration was determined. The cognitive impairment and anxiety behaviors were assessed by object recognition and elevated plus maze tests, respectively.

RESULTS

Elevation of MDA levels and a significant rise in the scoring of IL-1β staining were found in the Aβ group. The Aβ induced anxiogenic behavior, impaired novel object recognition memory, and increased the CSF levels of the total number of MVs. The number of Annexin V-positive MVs was significantly higher than Annexin V-negative MVs in all groups.

CONCLUSION

Data showed that Annexin V-positive MVs potentially have a significant contribution to the pathophysiology of the Aβ-induced cognitive impairment. To catch a clear image of microvesicle production in pathological conditions, both phenotypes of Annexin V-positive and Annexin V-negative MVs should be analyzed and reported.

Transcriptomic Analysis of Liver Tissue of Black Sea Bass (Centropristis striata) Exposed to High Nitrogen Environment

The black sea bass, Centropristis striata, is a potential candidate for commercial aquaculture. Due to inadequate removal of nitrogen in its breeding environment, C. striata exhibits increased nitrate concentration, which can cause acute toxicity, including energy metabolism damage and tissue damage. Therefore, RNA-seq technology was applied to characterize genes associated with toxicity tolerance under nitrate stress. The nitrate treatment caused significant changes in a total of 8920 genes, of which 2949 genes were up-regulated and 5971 genes were down-regulated. It was found that significantly enriched GO terms and KEGG were associated with blood microparticles, inhibitors of enzyme activity, and complement and coagulation cascade pathways. Furthermore, through bioinformatics analysis, it was found that these different pathways obtained in GO and KEGG enrichment analysis were mostly related to the immune and inflammatory response of fish. This study expands our understanding of the mechanism of nitrate stress affecting the liver function of C. striata.

Wharton's jelly mesenchymal stem cells: a concise review of their secretome and prospective clinical applications

Accumulating evidence indicates that most primary Wharton's jelly mesenchymal stem cells (WJ-MSCs) therapeutic potential is due to their paracrine activity, i.e., their ability to modulate their microenvironment by releasing bioactive molecules and factors collectively known as secretome. These bioactive molecules and factors can either be released directly into the surrounding microenvironment or can be embedded within the membrane-bound extracellular bioactive nano-sized (usually 30-150 nm) messenger particles or vesicles of endosomal origin with specific route of biogenesis, known as exosomes or carried by relatively larger particles (100 nm-1 μm) formed by outward blebbing of plasma membrane called microvesicles (MVs); exosomes and MVs are collectively known as extracellular vesicles (EVs). The bioactive molecules and factors found in secretome are of various types, including cytokines, chemokines, cytoskeletal proteins, integrins, growth factors, angiogenic mediators, hormones, metabolites, and regulatory nucleic acid molecules. As expected, the secretome performs different biological functions, such as immunomodulation, tissue replenishment, cellular homeostasis, besides possessing anti-inflammatory and anti-fibrotic effects. This review highlights the current advances in research on the WJ-MSCs' secretome and its prospective clinical applications.

Extracellular Vesicle MicroRNA in the Kidney

Most cells in our body release membrane-bound, nano-sized particles into the extracellular milieu through cellular metabolic processes. Various types of macromolecules, reflecting the physiological and pathological status of the producing cells, are packaged into such so-called extracellular vesicles (EVs), which can travel over a distance to target cells, thereby transmitting donor cell information. The short, noncoding ribonucleic acid (RNA) called microRNA (miRNA) takes a crucial part in EV-resident macromolecules. Notably, EVs transferring miRNAs can induce alterations in the gene expression profiles of the recipient cells, through genetically instructed, base-pairing interaction between the miRNAs and their target cell messenger RNAs (mRNAs), resulting in either nucleolytic decay or translational halt of the engaged mRNAs. As in other body fluids, EVs released in urine, termed urinary EVs (uEVs), carry specific sets of miRNA molecules, which indicate either normal or diseased states of the kidney, the principal source of uEVs. Studies have therefore been directed to elucidate the contents and biological roles of miRNAs in uEVs and moreover to utilize the gene regulatory properties of miRNA cargos in ameliorating kidney diseases through their delivery via engineered EVs. We here review the fundamental principles of the biology of EVs and miRNA as well as our current understanding of the biological roles and applications of EV-loaded miRNAs in the kidney. We further discuss the limitations of contemporary research approaches, suggesting future directions to overcome the difficulties to advance both the basic biological understanding of miRNAs in EVs and their clinical applications in treating kidney diseases. © 2023 American Physiological Society. Compr Physiol 13:4833-4850, 2023.

Pravastatin reduces plasma levels of extracellular vesicles in pregnancies at high risk of term preeclampsia

Introduction: Elevated plasma levels of extracellular vesicles have been associated with impaired placentation, angiogenesis imbalance, intravascular inflammation, and endothelial dysfunction in women with preeclampsia, thus suggesting that circulating vesicles may be a good therapeutic target for the treatment of the disease. Recently, statins have been considered a potential treatment for the prevention of preeclampsia because of their pleiotropic effects, including the improvement of endothelial dysfunction and inhibition of inflammatory responses. However, the effects of these drugs on circulating vesicles concentration in women at risk of preeclampsia have not been established. Herein, we aimed to assess the effects of pravastatin on circulating extracellular vesicle generation in women at high risk of term preeclampsia. Methods: In a sample of 68 singleton pregnant women participating in the multicenter, double-blind, placebo-controlled STATIN trial (Nº EducraCT 2016-005206-19 ISRCTN), 35 women received a placebo and 33 women received a 20 mg/day dose of pravastatin for approximately 3 weeks (from 35 to 37 weeks of gestation until delivery). Large extracellular vesicles were characterized and quantified by flow cytometry using annexin V and cell-specific antibodies directed against platelet, endothelial, leukocyte, and syncytiotrophoblast cell surface markers. Results: In women who received the placebo, a significant increase in the plasma levels of large extracellular vesicles from platelets (34%, p < 0.01), leukocytes (33%, p < 0.01), monocytes (60%, p < 0.01), endothelial cells (40%, p < 0.05), and syncytiotrophoblast cells (22%, p < 0.05) were observed. However, treatment with pravastatin significantly reduced the plasma levels of large extracellular vesicles from platelets (42%, p < 0.001), leukocytes (25%, p < 0.001), monocytes (61%, p < 0.001), endothelial cells (69%, p < 0.001), activated endothelial cells (55%, p < 0.001), and syncytiotrophoblast cells (44%, p < 0.001). Discussion: These results indicate that pravastatin reduces the levels of activated cell-derived membrane vesicles from the maternal vasculature, blood, and placental syncytiotrophoblast of women at high risk of term preeclampsia, suggesting that this statin may be beneficial in reducing endothelial dysfunction and pro-inflammatory and pro-coagulatory state characteristics of the disease.

Plasma Extracellular Vesicles Play a Role in Immune System Modulation in Minimal Hepatic Encephalopathy

Minimal hepatic encephalopathy (MHE) is associated with changes in the immune system including an increased pro-inflammatory environment and altered differentiation of CD4+ T lymphocytes. The mechanisms remain unknown. Changes in extracellular vesicle (EV) cargo including proteins and miRNAs could play a main role as mediators of immune system changes associated with MHE. The aim was to assess whether plasma EVs from MHE patients played a role in inducing the pro-inflammatory environment and altered differentiation of CD4+ T lymphocyte subtypes in MHE patients. We characterized the miRNA and protein cargo of plasma EVs from 50 cirrhotic patients (27 without and 23 with MHE) and 24 controls. CD4+ T cells from the controls were cultured with plasma EVs from the three groups of study, and the cytokine release and differentiation to CD4+ T-cell subtypes were assessed. Plasma EVs from MHE patients had altered miRNA and protein contents, and were enriched in inflammatory factors compared to the controls and patients without MHE. EVs from MHE patients modulated the expression of pro-inflammatory IL-17, IL-21, and TNF-α and anti-inflammatory TGF-β in cultured CD4+ T lymphocytes, and increased the proportion of Th follicular and Treg cells and the activation of Th17 cells. In conclusion, plasma EVs could play an important role in the induction of immune changes observed in MHE.

Circulating Microparticles Are Differentially Increased in Lowlanders and Highlanders with High Altitude Induced Pulmonary Hypertension during the Cold Season

The role of microparticles (MPs) and cold in high altitude pulmonary hypertension (HAPH) remains unexplored. We investigated the impact of long-term cold exposure on the pulmonary circulation in lowlanders and high-altitude natives and the role of MPs. Pulmonary hemodynamics were evaluated using Doppler echocardiography at the end of the colder and warmer seasons. We further examined the miRNA content of MPs isolated from the study participants and studied their effects on human pulmonary artery smooth muscle (hPASMCs) and endothelial cells (hPAECs). Long-term exposure to cold environment was associated with an enhanced pulmonary artery pressure in highlanders. Plasma levels of CD62E-positive and CD68-positive MPs increased in response to cold in lowlanders and HAPH highlanders. The miRNA-210 expression contained in MPs differentially changed in response to cold in lowlanders and highlanders. MPs isolated from lowlanders and highlanders increased proliferation and reduced apoptosis of hPASMCs. Further, MPs isolated from warm-exposed HAPH highlanders and cold-exposed highlanders exerted the most pronounced effects on VEGF expression in hPAECs. We demonstrated that prolonged exposure to cold is associated with elevated pulmonary artery pressures, which are most pronounced in high-altitude residents. Further, the numbers of circulating MPs are differentially increased in lowlanders and HAPH highlanders during the colder season.

Plasminogen Activator Inhibitor-1–Positive Platelet-Derived Extracellular Vesicles Predicts MACE and the Proinflammatory SMC Phenotype

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This study shows the existence of PAI-1⁺ PEVs. Approximately 20% of plasma PAI-1 is composed of PAI-1⁺ PEVs.

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Elevated PAI-1⁺ PEV levels were predictive of 1-year major adverse cardiac events in both the discovery and the validation cohort, with larger effect sizes than other clinical biomarkers.

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High PAI-1⁺ PEV levels did not affect thrombogenicity.

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Increasing doses of PAI-1⁺ PEVs promoted the proinflammatory VSMC state by enhancing proliferation and migration. Inhibition of the PAI-1:low-density lipoprotein–related receptor-1 pathway dampened the proinflammatory VSMC changes.

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PAI-1⁺ PEV is a promising biomarker for major adverse cardiac events, and targeting the PAI-1⁺ PEV–VSMC interaction may offer a novel target to modulate cardiac events in patients with coronary artery disease.

Patients with established coronary artery disease remain at elevated risk of major adverse cardiac events. The goal of this study was to evaluate the utility of plasminogen activator inhibitor-1–positive platelet-derived extracellular vesicles as a biomarker for major adverse cardiac events and to explore potential underlying mechanisms. Our study suggests these extracellular vesicles as a potential biomarker to identify and a therapeutic target to ameliorate neointimal formation of high-risk patients.

Intermittent Hypoxia and Atherosclerosis: From Molecular Mechanisms to the Therapeutic Treatment

Intermittent hypoxia (IH) has a dual nature. On the one hand, chronic IH (CIH) is an important pathologic feature of obstructive sleep apnea (OSA) syndrome (OSAS), and many studies have confirmed that OSA-related CIH (OSA-CIH) has atherogenic effects involving complex and interacting mechanisms. Limited preventive and treatment methods are currently available for this condition. On the other hand, non-OSA-related IH has beneficial or detrimental effects on the body, depending on the degree, duration, and cyclic cycle of hypoxia. It includes two main states: intermittent hypoxia in a simulated plateau environment and intermittent hypoxia in a normobaric environment. In this paper, we compare the two types of IH and summarizes the pathologic mechanisms and research advances in the treatment of OSA-CIH-induced atherosclerosis (AS), to provide evidence for the systematic prevention and treatment of OSAS-related AS.

An Overview of Circulating Pulmonary Arterial Hypertension Biomarkers

Pulmonary arterial hypertension (PAH), also known as Group 1 Pulmonary Hypertension (PH), is a PH subset characterized by pulmonary vascular remodeling and pulmonary arterial obstruction. PAH has an estimated incidence of 15-50 people per million in the United States and Europe, and is associated with high mortality and morbidity, with patients' survival time after diagnosis being only 2.8 years. According to current guidelines, right heart catheterization is the gold standard for diagnostic and prognostic evaluation of PAH patients. However, this technique is highly invasive, so it is not used in routine clinical practice or patient follow-up. Thereby, it is essential to find new non-invasive strategies for evaluating disease progression. Biomarkers can be an effective solution for determining PAH patient prognosis and response to therapy, and aiding in diagnostic efforts, so long as their detection is non-invasive, easy, and objective. This review aims to clarify and describe some of the potential new candidates as circulating biomarkers of PAH.

High circulating levels of CD62E+ and CD31+/Annexin V+ endothelium-derived microparticles in children with overweight/obesity: Evidence of early vascular damage

BACKGROUND

Obesity perturbs endothelium integrity, leading to endothelial activation, which predisposes the release of endothelium-derived microparticles (EMP). We measured the CD31⁺/annexin V⁺ and CD62E⁺ EMP levels to improve our understanding of their contribution to endothelial damage in children with overweight/obesity.

SUBJECT AND METHODS

In this cross-sectional study, 107 children with normal weight and 35 children with overweight/obesity were evaluated. Anthropometric measurement, blood pressure, biochemical profile was performed. Standardized flow cytometry methods were used to identify and quantify circulating CD31⁺/annexin V⁺ and CD62E⁺ EMP.

RESULTS

Children with overweight/obesity had significantly higher circulating levels of CD31⁺/annexin V⁺ (750 [600]) and CD62E⁺ (1400 [700]) EMP than those with normal weight (P < 0.001 for both). We found that EMP levels were positively correlated with body mass index (BMI), waist circumference, blood pressure, total cholesterol, low-density lipoprotein cholesterol (LDLc), and triglycerides. The multivariable logistic regression model revealed that the risks of having high EMP levels (> 75th percentile) were high in children with both large waist circumference and elevated LDLc level. Receiver operating characteristic (ROC) curves demonstrated that the LDLc levels showed significantly greater discrimination than waist circumference for both CD31⁺/annexin V⁺ (P = 0.031) as CD62E⁺ EMPs (P = 0.041).

CONCLUSIONS

Children with overweight/obesity have high circulating CD31⁺/annexin V⁺ and CD62E⁺ EMP levels, which may be an early sign of endothelial apoptosis and inflammatory activation in response to injury. These EMP levels were positively associated with several cardiometabolic risk factors. Our data underscore the negative influence of high-risk metabolic profiles on endothelial integrity in the early stages of childhood obesity.

Human umbilical cord mesenchymal stem cells regulate CD54 and CD105 in vascular endothelial cells and suppress inflammation in Kawasaki disease

OBJECTIVE

The objective was to evaluate the expression levels of CD31⁺CD54⁺ and CD31⁺CD105⁺ endothelial microparticles (EMPs) before and after intravenous immunoglobulin (IVIG) treatment of Kawasaki disease (KD). To explore the role of human umbilical cord mesenchymal stem cells (hucMSCs) in inhibiting endothelial inflammation in KD, the effects of hucMSCs on the expression of CD54 and CD105 in endothelial cells in KD were analyzed in vivo and in vitro.

METHODS

The concentrations of IL-1β and VEGF in the peripheral blood of KD or healthy children were detected, and the distributions of CD31⁺CD54⁺ and CD31⁺CD105⁺ EMPs in platelet-poor plasma (PPP) were analyzed by flow cytometry. Human umbilical vein endothelial cells (HUVECs) were first cocultured with the patients' peripheral blood mononuclear cells (PBMCs). Next, HUVECs were cocultured with hucMSCs after stimulation with inactivated serum from patients. Cell proliferation and migration activities were assessed, and the expression of CD54, CD105 and IL-1β was analyzed. In an in vivo study, hucMSCs were transplanted into KD mice. The locations and expression levels of CD54, CD105 and IL-1β in the heart tissues of mice were analyzed.

RESULTS

The levels of IL-1β and CD31⁺CD54⁺ EMPs were significantly higher before IVIG treatment and 2 weeks after treatment in KD patients (P < 0.01). However, the levels of VEGF and CD31⁺CD105⁺ EMPs increased significantly in KD only after IVIG treatment (P < 0.01). KD-inactivated serum stimulation combined with cocultivation of PBMCs can activate inflammation in HUVECs, leading to reduced cell proliferation and migration activities. Cocultivation also increased the expression of CD54 and decreased the expression of CD105 (P < 0.001). Cocultivation with hucMSCs can reverse these changes. Additionally, hucMSC transplantation downregulated the expression of IL-1β and CD54 and significantly upregulated the expression of CD105 in KD mice.

CONCLUSION

The expression levels of CD31⁺CD54⁺ and CD31⁺CD105⁺ EMPs showed inconsistent changes at different KD statuses, providing potential markers for clinical application. HucMSCs suppress inflammation and regulate the expression levels of CD54 and CD105 in vascular endothelial cells in KD, possibly providing a new basis for stem cell therapy for KD.

Increased circulating platelet and endothelial-derived microparticles in patients with cardiac syndrome X

BACKGROUND

Cardiac syndrome X (CSX) has been associated with endothelial dysfunction and inflammation. We conducted a case-control study to evaluate the association between plateletý and endothelial-derived microparticles (PMPs and EMPs), as specific quantitative plasma markers of endothelial dysfunction, and the presence of CSX.

METHODS

The present study was conducted on 40 CSX patients and 19 healthy individuals. C-reactive protein (CRP), and hematological and biochemical parameters were evaluated. The MP concentration in platelet-poor plasma (PPP) was quantitatively determined through flow cytometry using specific anti-human CD31, CD41a, CD62E, and CD144 antibodies.

RESULTS

The mean platelet volume (MPV) and positive CRP rate (≥ 3.8 mg/l) were higher in patients compared to controls (P = 0.020 and P = 0.010, respectively). The CD62E+, CD144+, and CD31+41− EMPs, as well as CD41+ and CD31+CD41+ PMPs showed significant increase in CSX patients compared to controls (P < 0.050). There were direct correlations between the mean percentage of detected EMPs and PMPs as well as between their expression intensity; however, a reverse correlation was seen between the percentage of MPs and CD144 and CD41. Moreover, the MP level was reversely associated with prothrombin time (PT) and partial thromboplastin time (PTT) values. Only CD31+CD41+ PMP was correlated with CRP.

CONCLUSION

It seems that EMPs and PMPs increase in CSX, which may contribute to various processes involved in the development of this syndrome.

Exosomes and Atherogenesis

Myocardial infarction and ischemic stroke are the leading causes of mortality worldwide. Atherosclerosis is their common pathological foundation. It is known that atherosclerosis is characterized by endothelial activation/injury, accumulation of inflammatory immune cells and lipid-rich foam cells, followed by the development of atherosclerotic plaque. Either from arterial vessel wall or blood circulation, endothelial cells, smooth muscle cells, macrophages, T-lymphocytes, B-lymphocytes, foam cells, and platelets have been considered to contribute to the pathogenesis of atherosclerosis. Exosomes, as natural nano-carriers and intercellular messengers, play a significant role in modulation of cell-to-cell communication. Under physiological or pathological conditions, exosomes can deliver their cargos including donor cell-specific proteins, lipids, and nucleic acids to target cells, which in turn affect the function of the target cells. In this review, we will describe the pathophysiological significance of various exosomes derived from different cell types associated with atherosclerosis, and the potential applications of exosome in clinical diagnosis and treatment.

Extracellular Microvesicles Released From Brain Endothelial Cells are Detected in Animal Models Of HIV-1 Signifying Unresolved Inflammation

Treatment of HIV-infected patients with antiretroviral therapy (ART) has effectively suppressed viral replication; however, the central nervous system is still a major target and reservoir of the virus leading to the possible development of HIV-associated neurocognitive disorders (HAND). Furthermore, a hallmark feature of HAND is the disruption of the blood–brain barrier that leads to loss of tight junction protein (TJP) complexes. Extracellular vesicles (EVs), released by every cell type in the body, occur in greater quantities in response to cellular activation or injury. We have found that inflammatory insults activate brain endothelial cells (EC) and induce the release of EVs containing TJPs such as Occludin. We thus hypothesized that HIV infection and unresolved neuroinflammation will result in the release of brain-EC derived EVs. Herein, our results show elevated levels of brain-EC EVs in a humanized mouse model of HIV infection. Furthermore, while ART reduced brain-EC EVs, it was unable to completely resolve increased vesicles detectable in the blood. In addition to inflammatory insults, HIV-1 viral proteins (Tat and gp120) increased the release of Occludin + vesicles from human brain microvasculature ECs. This increase in vesicle release could be prevented by knock-down of the small GTPase ARF6. ARF6 has been shown to regulate EV biogenesis in other cell types, and we provide further evidence for the involvement of ARF6 in brain EC derived EVs. Overall, this study offers insight into the process of brain vascular remodeling (via EVs) in the setting of neuroinflammation and thus provides possibilities for biomarker monitoring and targeting of ARF6.

Apoptotic microparticles mediate the association between bisphenol A and subclinical atherosclerosis in a young population: A population-based study

Bisphenol A (BPA) exposure is associated with atherosclerotic cardiovascular diseases. The interactions between BPA, extracellular microparticles (MPs), and atherosclerosis are unknown. A total of 103,756 young students participated in the mass urine-screening program in Taiwan between 1992 and 2000 were analyzed. After exclusion, 886 subjects were recruited to test the relationships between serum level of BPA, endothelial and platelet MPs as well as subclinical atherosclerosis represented by carotid artery intima-media thickness (CIMT). We found that an increment of one unit of log-BPA could lead to significant association between thicker CIMT and concentrations of endothelial microparticles and platelet microparticles in the cohort (odds ratio (OR) 1.23, P < 0.001). CD31 + /CD42a- (> 50%, OR 1.229, P = 0.001) and CD31 + /CD42a+ (≦ 50%, OR 1.262, P = 0.017 and > 50%, OR 1.212, P = 0.006) were significantly associated with thicker CIMT in the presence of elevated BPA. When considering the interactions between CD31 + /CD42a- and CD31 + /CD42a+ , we observed increased OR as CD31 + /CD42a- was greater than 50% (CD31 +/CD42a- > 50% and CD31 +/CD42a+ ≦ 50%, OR 1.356, P = 0.029; CD31 +/CD42a- > 50% and CD31 +/CD42a+ > 50%, OR 1.204, P = 0.014). Our study identified a higher risk of thicker CIMT associated with altered MPs in the presence of elevated BPA levels. BPA exposure is associated with endothelial dysfunction and subclinical atherosclerosis in a young population.

Extracellular Vesicles: Versatile Nanomediators, Potential Biomarkers and Therapeutic Agents in Atherosclerosis and COVID-19-Related Thrombosis

Cells convey information among one another. One instrument employed to transmit data and constituents to specific (target) cells is extracellular vesicles (EVs). They originate from a variety of cells (endothelial, immune cells, platelets, mesenchymal stromal cells, etc.), and consequently, their surface characteristics and cargo vary according to the paternal cell. The cargo could be DNA, mRNA, microRNA, receptors, metabolites, cytoplasmic proteins, or pathological molecules, as a function of which EVs exert different effects upon endocytosis in recipient cells. Recently, EVs have become important participants in a variety of pathologies, including atherogenesis and coronavirus disease 2019 (COVID-19)-associated thrombosis. Herein, we summarize recent advances and some of our own results on the role of EVs in atherosclerotic cardiovascular diseases, and discuss their potential to function as signaling mediators, biomarkers and therapeutic agents. Since COVID-19 patients have a high rate of thrombotic events, a special section of the review is dedicated to the mechanism of thrombosis and the possible therapeutic potential of EVs in COVID-19-related thrombosis. Yet, EV mechanisms and their role in the transfer of information between cells in normal and pathological conditions remain to be explored.

Endothelial Extracellular Vesicles: From Keepers of Health to Messengers of Disease

Endothelium has a rich vesicular network that allows the exchange of macromolecules between blood and parenchymal cells. This feature of endothelial cells, along with their polarized secretory machinery, makes them the second major contributor, after platelets, to the particulate secretome in circulation. Extracellular vesicles (EVs) produced by the endothelial cells mirror the remarkable molecular heterogeneity of their parent cells. Cargo molecules carried by EVs were shown to contribute to the physiological functions of endothelium and may support the plasticity and adaptation of endothelial cells in a paracrine manner. Endothelium-derived vesicles can also contribute to the pathogenesis of cardiovascular disease or can serve as prognostic or diagnostic biomarkers. Finally, endothelium-derived EVs can be used as therapeutic tools to target endothelium for drug delivery or target stromal cells via the endothelial cells. In this review we revisit the recent evidence on the heterogeneity and plasticity of endothelial cells and their EVs. We discuss the role of endothelial EVs in the maintenance of vascular homeostasis along with their contributions to endothelial adaptation and dysfunction. Finally, we evaluate the potential of endothelial EVs as disease biomarkers and their leverage as therapeutic tools.

Extracts of Thai Perilla frutescens nutlets attenuate tumour necrosis factor-α-activated generation of microparticles, ICAM-1 and IL-6 in human endothelial cells

Elevation of endothelial microparticles (EMPs) play an important role in the progression of inflammation-related vascular diseases such as cardiovascular diseases (CVDs). Thai perilla (Perilla frutescens) nutlets are rich in phenolic compounds and flavonoids that exert potent antioxidant and anti-inflammatory effects. We found that the ethyl acetate (EA) and ethanol (Eth) extracts of Thai perilla nutlets contain phenolic compounds such as luteolin, apigenin, chryseoriol and their glycosides, which exhibit antioxidant activity. The goal of the present study was to investigate the effects of the extracts on endothelial activation and EMPs generation in tumour necrosis factor-α (TNF-α)-induced EA.hy926 cells. We found that TNF-α (10 ng/ml) activated EA.hy926 cells and subsequently generated EMPs. Pre-treatment with the extracts significantly attenuated endothelial activation by decreasing the expression of the intracellular adhesion molecule-1 (ICAM-1) in a dose-dependent manner. Only the Eth extract showed protective effects against overproduction of interleukin-6 (IL-6) in the activated cells. Furthermore, the extracts significantly reduced TNF-α-enhanced EMPs generation in a dose-dependent manner. In conclusion, Thai perilla nutlet extracts, especially the Eth extract, may have potential to protect endothelium against vascular inflammation through the inhibition of endothelial activation and the generation of endothelial microparticles (EMPs).

Endothelial microvesicles carrying Src-rich cargo impair adherens junction integrity and cytoskeleton homeostasis

Aims

Microvesicles (MVs) conduct intercellular communication and impact diverse biological processes by transferring bioactive cargos to other cells. We investigated whether and how endothelial production of MVs contribute to vascular dysfunction during inflammation.

Methods and results

We measured the levels and molecular properties of endothelial-derived MVs (EC-MVs) from mouse plasma following a septic injury elicited by cecal ligation and puncture, as well as those from supernatants of cultured endothelial cells stimulated by inflammatory agents including cytokines, thrombin, and complement 5a. The mouse studies showed that sepsis caused a significant increase in total plasma vesicles and VE-cadherin⁺ EC-MVs compared to sham control. In cultured ECs, different inflammatory agents caused diverse patterns of EC-MV production and cargo contents. When topically applied to endothelial cells, EC-MVs induced a cytoskeleton-junction response characterized by myosin light chain phosphorylation, contractile fibre reorganization, VE-cadherin phosphorylation, and adherens junction dissociation, functionally measured as increased albumin transendothelial flux and decreased barrier resistance. The endothelial response was coupled with protein tyrosine phosphorylation promoted by MV cargo containing c-Src kinase, whereas MVs produced from c-Src deficient cells did not exert barrier-disrupting effects. Additionally, EC-MVs contribute to endothelial inflammatory injury by promoting neutrophil-endothelium adhesion and release of neutrophil extracellular traps containing citrullinated histones and myeloperoxidase, a response unaltered by c-Src knockdown.

Conclusion

Endothelial-derived microparticles cause endothelial barrier dysfunction by impairing adherens junctions and activating neutrophils. The signalling mechanisms underlying the endothelial cytoskeleton-junction response to EC-MVs involve protein phosphorylation promoted by MV cargo carrying c-Src. However, EC-MV-induced neutrophil activation was not dependent on c-Src.

Biological insight into the extracellular vesicles in women with and without gestational diabetes

PURPOSE

Gestational diabetes mellitus (GDM) is the most common metabolic disorder in pregnancy, with increasing prevalence worldwide and still unclear pathogenic mechanisms. Extracellular vesicles (EVs) are emerging as potential biomarkers of disease-specific pathways in metabolic disorders, but their potential role in GDM is not fully understood. Therefore, the main aim of this study was to evaluate the link between EVs and hyperglycaemia during pregnancy.

METHODS

We assessed 50 GDM women and 50 controls at the third trimester of pregnancy in whom we collected demographic characteristics and clinical and anthropometric parameters. In addition, the circulating total EVs (tEVs) and their subpopulations were assessed using flow cytometry.

RESULTS

The levels of tEVs and EVs subtypes, expressed as median and interquartile range, were not significantly different between two groups; however, adipocyte-derived EVs (aEVs) concentration, expressed as percentage, was higher in controls than in GDM women (p = 0.045). In addition, a significant correlation was observed between aEVs (%) and third trimester total cholesterol (p = 0.022) within the GDM group. Furthermore, a significant correlation between endothelial-derived EVs (eEVs) and platelet-derived EVs (pEVs) within both groups was found, as well as a significant relation between aEVs and pEVs.

CONCLUSIONS

These data, although preliminary, represent the starting point for further studies to determine the role of circulating EVs in GDM.

Assessment of Endothelial Injury and Pro-Coagulant Activity Using Circulating Microvesicles in Survivors of Allogeneic Hematopoietic Cell Transplantation

(1) Background: survivors of allogeneic hematopoietic cell transplantation (alloHCT) suffer from morbidity and mortality due to cardiovascular events. We hypothesized that vascular injury and pro-coagulant activity are evident in alloHCT survivors without existing alloHCT complications or relapse. (2) Methods: we enrolled consecutive adult alloHCT survivors without established cardiovascular disease and control individuals matched for traditional cardiovascular risk factors (January-December 2019). Circulating microvesicles (MVs) of different cellular origins (platelet, erythrocyte, and endothelial) were measured by a standardized flow cytometry protocol as novel markers of vascular injury and pro-coagulant activity. (3) Results: we recruited 45 survivors after a median of 2.3 (range 1.1-13.2) years from alloHCT, and 45 controls. The majority of patients suffered from acute (44%) and/or chronic (66%) graft-versus-host disease (GVHD). Although the two groups were matched for traditional cardiovascular risk factors, alloHCT survivors showed significantly increased platelet and erythrocyte MVs compared to controls. Within alloHCT survivors, erythrocyte MVs were significantly increased in patients with a previous history of thrombotic microangiopathy. Interestingly, endothelial MVs were significantly increased only in alloHCT recipients of a myeloablative conditioning. Furthermore, MVs of different origins showed a positive association with each other. (4) Conclusions: endothelial dysfunction and increased thrombotic risk are evident in alloHCT recipients long after alloHCT, independently of traditional cardiovascular risk factors. An apparent synergism of these pathophysiological processes may be strongly involved in the subsequent establishment of cardiovascular disease.

Circulating Neutrophil-Derived Microparticles Associated with the Prognosis of Patients with Sepsis

Introduction

Because of its high morbidity and mortality, sepsis remains the leading cause of death in the ICU. Microparticles (MP) have been largely studied as potential diagnostic or prognostic markers in various diseases including sepsis.

Objective

The biological and clinical relevance of neutrophil-derived microparticles (NDMPs) within the MP population remains unclear. The objective of this study was to elucidate the relationship between plasma NDMPs and the prognosis of patients with sepsis and/or septic shock.

Methods

The study was designed as an observational, noninterventional clinical study. The cohort for this study included 40 sepsis and 40 septic shock patients together with 10 healthy controls admitted to the Intensive Care Unit (ICU) and the Health Surveillance Center in the Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong, China, from January to November 2018, respectively. The degree of critical disease for sepsis and septic shock was evaluated, with data analyses conducted from 2018 to 2019.

Results

On days 1, 3 and 5 post-admission a series of data including plasma NDMP levels, patient demographics, TNF-α levels, IL-6 levels, sTREM-1 levels, and the sepsis severity score measurements were collected. A survival curve was plotted against levels of plasma NDMPs. Levels of NDMPs were observed to be higher in the septic shock patients than in the sepsis patients on days 1, 3, and 5 post-ICU admission (p < 0.05). NDMP levels were significantly increased in sepsis and septic shock patients with a parallel increase in pro-inflammatory mediators and sepsis severity score (p < 0.05) as well as mortality.

Conclusion

Our data suggest that NDMPs may be a biomarker of sepsis severity and mortality although its implications on sepsis prognosis warrant further study.

Early Cardiovascular Risk in E-cigarette Users: the Potential Role of Metals

PURPOSE OF REVIEW

Electronic cigarettes (e-cigs) are a source of metals. Epidemiologic and experimental evidence support that metals are toxic to the cardiovascular system. Little is known, however, about the role that e-cig metals may play as toxicants for the possible cardiovascular effects of e-cig use. The goal of this narrative review is to summarize the evidence on e-cig use and metal exposure and on e-cig use and cardiovascular toxicity and discuss the research needs.

RECENT FINDINGS

In vitro studies show cytotoxicity and increased oxidative stress in myocardial cells and vascular endothelial cells exposed to e-liquids and e-cig aerosols, with effects partially reversed with antioxidant treatment. There is some evidence that the heating coil plays a role in cell toxicity. Mice exposed to e-cigs for several weeks showed higher levels of oxidative stress, inflammation, platelet activation, and thrombogenesis. Cross-over clinical experiments show e-cig use alters nitric oxide-mediated flow-mediated dilation, endothelial progenitor cells, and arterial stiffness. Cross-sectional evidence from large nationally representative samples in the USA support that e-cig use is associated with self-reported myocardial infarction. Smaller studies found associations of e-cig use with higher oxidized low-density protein and heart variability compared to healthy controls. Numerous studies have measured elevated levels of toxic metals in e-cig aerosols including lead, nickel, chromium, and manganese. Arsenic has been measured in some e-liquids. Several of these metals are well known to be cardiotoxic. Numerous studies show that e-cigs are a source of cardiotoxic metals. Experimental studies (in vitro, in vivo, and clinical studies) show acute toxicity of e-cigs to the vascular system. Studies of long-term toxicity in animals and humans are missing. Longitudinal studies with repeated measures of metal exposure and subclinical cardiovascular outcomes (e.g., coronary artery calcification) could contribute to determine the long-term cardiovascular effects of e-cigs and the potential role of metals in those effects.

Endothelial and Leukocyte-Derived Microvesicles and Cardiovascular Risk After Stroke: PROSCIS-B

OBJECTIVE

To determine the role of circulating microvesicles (MV) on long-term cardiovascular outcomes after stroke, we measured them in patients with first-ever stroke with a 3-year follow-up.

METHODS

In the Prospective Cohort With Incident Stroke Berlin (PROSCIS-B), patients with first-ever ischemic stroke were followed up for 3 years. The primary combined endpoint consisted of recurrent stroke, myocardial infarction, and all-cause mortality. Citrate-blood levels of endothelial MV (EMV), leukocyte-derived MV (LMV), monocytic MV (MMV), and platelet-derived MV (PMV) were measured with flow cytometry. Kaplan-Meier curves and adjusted Cox proportional hazards models were used to estimate the effect of MV levels on the combined endpoint.

RESULTS

Five hundred seventy-one patients were recruited (median age 69 years, 39% female, median NIH Stroke Scale score 2, interquartile range 1-4), and 95 endpoints occurred. Patients with levels of EMV (adjusted hazard ratio [HR] 2.5, 95% confidence interval [CI] 1.2-4.9) or LMV (HR 3.1, 95% CI 1.4-6.8) in the highest quartile were more likely to experience an event than participants with lower levels with the lowest quartile used as the reference category. The association was less pronounced for PMV (HR 1.7, 95% CI 0.9-3.2) and absent for MMV (HR 1.1, 95% CI 0.6-1.8).

CONCLUSION

High levels of EMV and LMV after stroke were associated with worse cardiovascular outcome within 3 years. These results reinforce that endothelial dysfunction and vascular inflammation affect the long-term prognosis after stroke. EMV and LMV might play a role in risk prediction for stroke patients.

CLINICALTRIALSGOV IDENTIFIER

NCT01363856.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence of the effect of MV levels on subsequent stroke, myocardial infarction, or all-cause mortality in survivors of mild stroke.

Impact of Epicatechin on the Procoagulant Activities of Microparticles

Microparticles play a role in cardiovascular disease pathology. The flavanol-like epicatechin is increasingly considered due to its cardioprotective effects. The aim of this study was to investigate the impact of epicatechin on microparticle generation, phenotype and procoagulant properties. Plasma samples from 15 healthy subjects were incubated with increasing concentrations of epicatechin (1 to 100 μM). Then, the expression of glycoprotein IIb, phosphatidylserine (PS), glycoprotein Ib (GPIb) and P-selectin was assessed by flow cytometry analysis after (or not) platelet stimulation. Microparticle procoagulant activity was determined using Zymuphen^TM MP and Zymuphen^TM MP-TF for phospholipid and tissue factor content, and with thrombin generation (TG) assays for procoagulant function. Platelet microparticles that express GPIb (/µL) decreased from 20,743 ± 24,985 (vehicle) to 14,939 ± 14,333 (p = 0.6), 21,366 ± 16,949 (p = 0.9) and 15,425 ± 9953 (p < 0.05) in samples incubated with 1, 10 and 100 µM epicatechin, respectively. Microparticle concentration (nM PS) decreased from 5.6 ± 2.0 (vehicle) to 5.1 ± 2.2 (p = 0.5), 4.5 ± 1.5 (p < 0.05) and 4.7 ± 2.0 (p < 0.05) in samples incubated with 1, 10 and 100µM epicatechin, respectively. Epicatechin had no impact on tissue factor-positive microparticle concentration. Epicatechin decreased TG (endogenous thrombin potential, nM.min) from 586 ± 302 to 509 ± 226 (p = 0.3), 512 ± 270 (p = 0.3) and 445 ± 283 (p < 0.05). These findings indicate that epicatechin affects microparticle release, phenotype and procoagulant properties.

The Mediterranean diet decreases prothrombotic microvesicle release in asymptomatic individuals at high cardiovascular risk

BACKGROUND & AIMS

Circulating microvesicles (cMV) are small phospholipid-rich vesicles that contribute to the atherothrombotic process, and are biomarkers of cardiovascular disease (CVD) burden and progression. Diet is a cornerstone for CVD prevention, but dietary effects on cMV shedding are poorly characterized. We aimed at assessing the long term effects of a Mediterranean diet compared to a low-fat diet (LFD) on MV shedding by cells of the blood and vascular compartments in patients at high cardiovascular risk treated as per guidelines.

METHODS

A total of 155 participants from the PREDIMED trial free of cardiovascular events after a mean follow-up of 5 years (n = 53 from the Mediterranean diet supplemented with extra-virgin olive oil -EVOO-; n = 49 from the Mediterranean diet supplemented with mixed nuts -Nuts-; and n = 53 from the LFD) were included in the study. At baseline and after one-year intervention, cMV were quantified and characterized by flow cytometry to identify their activated parental cell origin and prothrombotic potential by Annexin V (AV) binding.

RESULTS

After one year of dietary intervention, platelet-derived PAC-1⁺/AV⁺ and CD62P⁺/AV⁺ cMV concentrations were lower in the Nuts group compared with the LFD and EVOO interventions (P = 0.036 and 0.003, respectively). In addition, prothrombotic cMV carrying tissue factor (CD142⁺/AV⁺) and CD11a⁺/AV⁺ cMV derived from activated cells, were significantly lower in both Mediterranean diet (EVOO and Nuts) interventions compared to one year of LFD (P < 0.0001 and 0.028, respectively). SMAα⁺/AV^- cMV were lower in the LFD compared to the Nuts group after one year of intervention (P = 0.038).

CONCLUSIONS

cMV are markers of cell activation and vascular injury that appear to be sensitive to dietary changes. Following a Mediterranean diet rich in EVOO or nuts is associated with lower cell activation towards a pro-atherothrombotic phenotype, suggesting a delay in the development of CV complications.

Inside(sight) of tiny communicator: exosome biogenesis, secretion, and uptake

Discovered in the late 1980s as an extracellular vesicle of endosomal origin secreted from reticulocytes, exosomes recently gained scientific attention due to its role in intercellular communication. Exosomes have now been identified to carry cell-specific cargo of nucleic acids, proteins, lipids, and other biologically active molecules. Exosomes can be selectively taken up by neighboring or distant cells, which has shown to result in structural and functional responses in the recipient cells. Recent advances indicate the regulation of exosomes at various steps, including their biogenesis, selection of their cargo, as well as cell-specific uptake. This review will shed light on the differences between the type of extracellular vesicles. In this review, we discuss the recent progress in our understanding of the regulation of exosome biogenesis, secretion, and uptake.

Novel Biomarkers for Evaluation of Endothelial Dysfunction

Endothelial dysfunction is one of the earliest indicators of cardiovascular (CV) dysfunction, and its evaluation would be of considerable importance to stratify CV risk of many diseases and to assess the efficacy of atheroprotective treatments. Flow-mediated dilation is the most widely used method to study endothelial function. However, it is operator-dependent and can be influenced by physiological variations. Circulating biomarkers are a promising alternative. Due to the complexity of endothelial function, many of the biomarkers studied do not provide consistent information about the endothelium when measured alone. New circulating markers are being explored and some of them are thought to be suitable for the clinical setting. In this review, we focus on novel biomarkers of endothelial dysfunction, particularly endothelial microparticles, endocan, and endoglin, and discuss whether they fulfill the criteria to be applied in clinical practice.

Increased microparticle levels in middle-aged and elderly patients with insomnia may be involved in the pathogenesis of arteriosclerosis

BACKGROUND

Insomnia may affect vascular factors and promote arteriosclerosis. Microparticles (MPs) are a heterogeneous group of bioactive small vesicles that can be found in blood and body fluids following activation, necrosis or apoptosis of virtually any eukaryotic cells. MPs are believed to participate in the pathogenesis of atherosclerosis. Few studies have been concerned with the microparticle level in patients with sleep disorder. The purpose of the present study is to measure the levels of endothelial microparticles (EMPs), platelet microparticles (PMPs) and leukocyte-derived microparticles (LMPs) in middle-aged and elderly patients with or without insomnia.

METHODS

Patients with insomnia (N.=30) and without insomnia (N.=18) were enrolled. The insomnia group covered patients with chronic insomnia (N.=16) and acute insomnia (N.=14). Levels of EMPs (CD31 +, CD62E +) and PMPs (CD41a +, CD42a +) and granulocyte-derived (CD11a +) MPs were measured. Flow cytometry was performed on the Beckman Coulter analyzer. Reference gate was defined for the level of MPs using 0.22-0.45-0.88μm microspheres, and the size gate for MPs was 0.5-1.0μm.

RESULTS

Of all types of MPs detected, the levels of CD31 +MPs, CD62E +MPs and CD11a +MPs were significantly higher in the insomnia group than in the non-insomnia group (P<0.05). Besides, compared with acute insomnia, the levels of CD31 + MPs and CD11a +MPs were significantly higher in chronic insomnia (P<0.001).

CONCLUSIONS

In insomnia patients, atherosclerosis progression may be increased by the CD31+ EMPs-mediated apoptosis and endothelial injury. The level of CD11a+ LMPs kept increasing as insomnia persisted, which may indicate atherosclerosis progression.

Pollution, Particles, and Dementia: A Hypothetical Causative Pathway

Epidemiological studies of air pollution have shown associations between exposure to particles and dementia. The mechanism of this is unclear. As these seem unlikely in terms of the very small dose likely to reach the brain in usual Western urban circumstances, we extend our 1995 hypothetical explanation of the association of air pollution with cardiac deaths as a plausible alternative explanation of its associations with dementia. Since our original proposal, it has become apparent that inflammation may be carried by blood from organ to organ by biologic microparticles derived from cell membranes. These transmit inflammatory messages to endothelial cells throughout the body as part of a general defensive response to assumed bacterial infection; particulate air pollution has recently been shown to be associated with their release into the blood. We propose that episodic release of biologic microparticles from pollution-induced lung inflammation causes secondary inflammation in the blood-brain barrier and cerebral microbleeds, culminating over time in cognitive impairment. Ultimately, by incomplete repair and accumulation of amyloid, this increases the risk of Alzheimer’s disease. Importantly, this mechanism may also explain the relationships of other inflammatory conditions and environmental factors with cognitive decline, and point to new opportunities to understand and prevent dementia.

Platelet-derived bio-products: Classification update, applications, concerns and new perspectives

Platelet derived bio-products in the form of platelet rich plasma, plasma rich in growth factors, or plasma-free platelet releasates, are being studied worldwide with the aim of proving their efficacy in tissue regeneration within many different clinical areas, such as traumatology, maxillofacial surgery, ophthalmology, dermatology and otorhinolaryngology, amongst others. The current lack of consensus in the preparation method and application form, or in the quality assessment of each bio-product, precludes adequate interpretation of the relevance of reported clinical outcomes, and, while many in clinicians are very positive about them, many are sceptic. Relevant aspects of these products are considered to propose a classification nomenclature which would aid a comprehensive comparison of clinical outcomes of bio-products of the same characteristics. Finally, the uses of platelet-derived bio-products in in vitro culture (for cell therapy purposes) as a substitute of animal-origin sera, and other future perspectives of applications of platelet-derived bio-products are discussed.

The Level of Circulating Microparticles in Patients with Coronary Heart Disease: a Systematic Review and Meta-Analysis

BACKGROUND/AIMS

To assess the correlation between microparticles (MPs) and subgroups of coronary heart disease (CHD), including stable angina (SA), unstable angina (UA), and myocardial infarction (MI).

METHODS

A literature search was carried out systematically to identify available case-control studies. The level of MPs was compared and MPs' merged standardized mean differences (SMDs) were pooled for the meta-analysis.

RESULTS

Six studies met the inclusion criteria and were used for systematic review and meta-analysis. The level of MPs was higher in patients with CHD than that in the NS (normal subjects) group (SMD 2.28; 95% confidence interval (CI) 1.70-2.85; P = 0.000), and was also significantly different in subgroups of CHD (UA vs SA: SMD 2.35, 95% CI 1.56-3.14, P = 0.000; MI vs SA: SMD 3.08, 95% CI 2.07-4.09, P = 0.000; MI vs UA: SMD 0.83, 95% CI 0.41-1.26, P = 0.000). The similar results were also found in subgroups analyses of CD31⁺CD42^- endothelium-derived microparticles (EMPs) and CD144⁺EMPs.

CONCLUSION

The level of MPs, especially CD31⁺CD42^-EMPs and CD144⁺EMPs, had an increasing trend with the degree of CHD: NS<SA<UA<MI, suggesting that MPs might be a potential biomarker to identify SA, UA, and MI.

Engineered human platelet-derived microparticles as natural vectors for targeted drug delivery

Drug targeting has opened a new paradigm in therapeutics with development of delivery vectors like liposomes and polymeric nanoparticles. Although their clinical application is crippled by limited biological adaptability. Off-target toxicity and biocompatibility still remains one of the critical problems in anticancer therapeutics that can be life-threatening. Here we report a quick, simple and facile method of engineering human platelets to generate drug loaded platelet-derived microparticles (PMPs) by top-down approach, which are biocompatible and naturally target leukemia cells. Drug loaded PMPs and cancer cell uptake were characterized by flow cytometry, confocal microscopy, Nanoparticle Tracking Analysis and fluorimetry. Effective drug delivery was tested in cancer cell lines as well as in clinical samples from leukemia patients. We explored that PMPs are capable of carrying multiple drug payloads, have long shelf life and can be harvested in large quantity in short period. Importantly, PMPs exhibited remarkably higher toxicity towards cancer cells than free drug and had lower escape into extravascular spaces. Transfer of drug to cancer cells of leukemia patients was significantly higher than free drug, when delivered through PMPs. Our experiments validated therapeutic application of PMPs as biocompatible drug delivery vector against cancer cells with minimal off-target delivery.

Shiga toxin signals via ATP and its effect is blocked by purinergic receptor antagonism

Shiga toxin (Stx) is the main virulence factor of enterohemorrhagic Escherichia coli (EHEC), that cause gastrointestinal infection leading to hemolytic uremic syndrome. The aim of this study was to investigate if Stx signals via ATP and if blockade of purinergic receptors could be protective. Stx induced ATP release from HeLa cells and in a mouse model. Toxin induced rapid calcium influx into HeLa cells, as well as platelets, and a P2X1 receptor antagonist, NF449, abolished this effect. Likewise, the P2X antagonist suramin blocked calcium influx in Hela cells. NF449 did not affect toxin intracellular retrograde transport, however, cells pre-treated with NF449 exhibited significantly higher viability after exposure to Stx for 24 hours, compared to untreated cells. NF449 protected HeLa cells from protein synthesis inhibition and from Stx-induced apoptosis, assayed by caspase 3/7 activity. The latter effect was confirmed by P2X1 receptor silencing. Stx induced the release of toxin-positive HeLa cell- and platelet-derived microvesicles, detected by flow cytometry, an effect significantly reduced by NF449 or suramin. Suramin decreased microvesicle levels in mice injected with Stx or inoculated with Stx-producing EHEC. Taken together, we describe a novel mechanism of Stx-mediated cellular injury associated with ATP signaling and inhibited by P2X receptor blockade.

Circulating Endothelial Microparticles and Aortic Stiffness in Patients with Type 2 Diabetes Mellitus

Diabetes mellitus represents a metabolic disorder the incidence of which has been on the increase in recent years. The well-known long-term complications of this disease encompass a wide spectrum of renal, neurological and cardiovascular conditions. The aim of the study was to investigate the serum concentration of endothelial microparticles (EMPs) as well as selected noninvasive parameters of the ascending aorta stiffness calculated with echocardiography. In this study, 58 patients were enrolled-38 subjects diagnosed with type 2 diabetes mellitus (T2DM) and 20 healthy controls. The analyzed populations did not differ significantly with respect to age, renal function, systolic and diastolic blood pressure. The patients with diabetes and concomitant hypertension presented higher levels of EMPs in comparison with diabetic normotensive subjects. Among patients with diabetes and hypertension, aortic stiffness assessed with the elasticity index (Ep) was higher and the aortic compliance index (D) lower than in the diabetic normotensive group. No correlation between the amount of EMPs and lipid profile, C-reactive protein (CRP) level and glycemia, was observed in the studied group. There was, however, a statistically significant positive correlation between the creatinine level and amount of EMPs, while the negative relationship was documented for EMPs level and the estimated glomerular filtration rate (eGFR).

Increased erythrocyte- and platelet-derived microvesicles in newly diagnosed type 2 diabetes mellitus

AIM

To investigate the thrombotic microenvironment in early stages of type 2 diabetes mellitus measuring platelet-derived, endothelial-derived and erythrocyte-derived microvesicles.

METHODS

We recruited 50 newly diagnosed type 2 diabetes mellitus patients who did not receive glucose-lowering treatment except for metformin and 25 matched non-type 2 diabetes mellitus volunteers. Microvesicles were measured with flow cytometry, glycated haemoglobin with high-performance liquid chromatography and advanced glycation end products with enzyme-linked immunosorbent assay.

RESULTS

Type 2 diabetes mellitus patients showed significantly higher levels of platelet-derived microvesicles [195/μL (115-409) vs 110/μL (73-150), p = 0.001] and erythrocyte-derived microvesicles [26/μL (9-100) vs 9/μL (4-25), p = 0.007] compared to non-type 2 diabetes mellitus individuals. Platelet-derived microvesicles were positively associated with fasting blood glucose (p = 0.026) and glycated haemoglobin (p = 0.002). Erythrocyte-derived microvesicles were also positively associated with fasting blood glucose (p = 0.018) but not with glycated haemoglobin (p = 0.193). No significant association was observed between platelet-derived microvesicles (p = 0.126) or erythrocyte-derived microvesicles (p = 0.857) and advanced glycation end products. Erythrocyte-derived microvesicles predicted the presence of type 2 diabetes mellitus, independently of platelet-derived microvesicles.

CONCLUSION

In newly diagnosed type 2 diabetes mellitus, ongoing atherothrombosis is evident during the early stages as evidenced by increased microvesicles levels. Furthermore, the association with glycemic profile suggests that microvesicles represent not only a novel mechanism by which hyperglycemia amplifies thrombotic tendency in type 2 diabetes mellitus but also early markers of thrombosis highlighting the need for earlier management of hyperglycemia.

Early Prediction of Cardiovascular Risk after Hematopoietic Cell Transplantation: Are We There Yet?

Cardiovascular (CV) events have emerged as a major cause of morbidity and mortality among hematopoietic cell transplantation (HCT) survivors. Accumulating evidence supports the presence of increased CV risk in HCT recipients. Most studies have focused mainly on traditional CV risk factors, such as the metabolic syndrome and hypertension. However, detection of these factors suggests the development of irreversible overt clinical atherosclerosis. Therefore, earlier prediction of CV risk is needed to prevent CV morbidity and mortality in these patients. In the field of CV research, endothelial dysfunction is considered an early event in the pathophysiology of CV risk factors, and a number of markers have been proposed for its assessment. In addition, markers of subclinical target organ damage have been introduced to implement CV risk prediction and early preventive or intensive therapeutic interventions. Furthermore, a number of CV models have been suggested aiming for optimal stratification of patients. Preliminary studies have indicated excess CV risk using these early markers in HCT recipients. However, their role in the pathophysiology and clinical practice in HCT survivors remains largely understudied. Taking into account the need for increased awareness from treating physicians in this evolving setting, we conducted a state-of-the-art review aiming to summarize current knowledge on endothelial dysfunction, subclinical target organ damage, and CV risk prediction in HCT survivors.

Urinary extracellular vesicles as a source of biomarkers reflecting renal cellular biology in human disease

For more than a decade, extracellular vesicles (EVs) have been the focus of extensive research efforts attempting to uncover their biological function in health and disease. Likewise, numerous studies have investigated them as a source of potential biomarkers to complement or replace the routine diagnostic procedures. Urinary extracellular vesicles take a distinct place among these studies, as they hold the promise to reflect changes in the cellular biology of the nephron and can be isolated without any invasive procedure. However, their potential has been insufficiently exploited since both their biological function and their use for diagnostic purposes in human disease have only gained increasing attention in the last years. This review aims to give an overview of the present knowledge about urinary extracellular vesicles with a special focus on novel nomenclature recommendations, current techniques for urinary EV separation and potential biomarkers that have emerged from the analysis of urinary EVs.

Loss of Renal Peritubular Capillaries in Hypertensive Patients Is Detectable by Urinary Endothelial Microparticle Levels

Hypertension, an important cause of chronic kidney disease, is characterized by peritubular capillary (PTC) loss. Circulating levels of endothelial microparticles (EMPs) reflect systemic endothelial injury. We hypothesized that systemic and urinary PTC-EMPs levels would reflect renal microvascular injury in hypertensive patients. We prospectively measured by flow cytometry renal vein, inferior vena cava, and urinary levels of EMPs in essential (n=14) and renovascular (RVH; n=24) hypertensive patients and compared them with peripheral blood and urinary levels in healthy volunteers (n=14). PTC-EMPs were identified as urinary exosomes positive for the PTC marker plasmalemmal-vesicle-associated protein. In 7 RVH patients, PTC and fibrosis were also quantified in renal biopsy, and in 18 RVH patients, PTC-EMPs were measured again 3 months after continued medical therapy with or without stenting (n=9 each). Renal vein and systemic PTC-EMPs levels were not different among the groups, whereas their urinary levels were elevated in both RVH and essential hypertension versus healthy volunteers (56.8%±12.7% and 62.8%±10.7% versus 34.0%±17.8%; both P≤0.001). Urinary PTC-EMPs levels correlated directly with blood pressure and inversely with estimated glomerular filtration rate. Furthermore, in RVH, urinary PTC-EMPs levels correlated directly with stenotic kidney hypoxia, histological PTC count, and fibrosis and inversely with cortical perfusion. Three months after treatment, the change in urinary PTC-EMPs levels correlated inversely with a change in renal function ( r=-0.582; P=0.011). Therefore, urinary PTC-EMPs levels are increased in hypertensive patients and may reflect renal microcirculation injury, whereas systemic PTC-EMPs levels are unchanged. Urinary PTC-EMPs may be useful as novel biomarkers of intrarenal capillary loss.

Effects of resveratrol on laminar shear stress-induced mitochondrial biogenesis in human vascular endothelial cells

[Purpose]

The purpose of the study was to determine the combined effects of resveratrol supplementation with high-flow LSS on mitochondrial biogenesis in human vascular endothelial cells.

[Methods]

Cultured human umbilical vein endothelial cells were treated with 20 μM of RSV. For the shear experiments, cells grown to a >90% confluence were exposed to physiological levels of LSS (5 to 20 dyne/cm2) for 12 to 36 hours using a cone and plate shear apparatus. Gene expressions were analyzed by western blotting.

[Results]

Depletion of mitochondrial integrity was directly associated with increase in endothelial activation/dysfunction. The expressions of mitochondrial biogenesis regulator genes, such as SIRT1, PGC-1α, and TFAM, and the mitochondrial contents were significantly increased after treatment with both resveratrol and high-flow LSS for 12 hours. However, supplementation of resveratrol to high-flow LSS for a prolonged duration had no synergistic effect on the levels of mitochondrial biogenesis regulator gene expressions and mitochondrial content compared to the LSS treatment alone.

[Conclusion]

The present study demonstrated that the supplementation of resveratrol to high-flow LSS has no synergistic effects on enhancing mitochondrial integrity in human vascular endothelial cells.

Extracellular vesicles in lung health, disease, and therapy

Both physiological homeostasis and pathological disease processes in the lung typically result from complex, yet coordinated multicellular responses that are synchronized via paracrine and endocrine intercellular communication pathways. Of late, extracellular vesicles have emerged as important information shuttles that can coordinate and disseminate homeostatic and disease signals. In parallel, extracellular vesicles in biological fluids such as sputum, mucus, epithelial lining fluid, edema fluid, the pulmonary circulation, pleural fluid, and lymphatics have emerged as promising candidate biomarkers for diagnosis and prognosis in lung disease. Extracellular vesicles are small, subcellular, membrane-bound vesicles containing cargos from parent cells such as lipids, proteins, genetic information, or entire organelles. These cargos endow extracellular vesicles with biologically active information or functions by which they can reprogram their respective target cells. Recent studies show that extracellular vesicles found in lung-associated biological fluids play key roles as biomarkers and effectors of disease. Conversely, administration of naïve or engineered extracellular vesicles with homeostatic or reparative effects may provide a promising novel protective and regenerative strategy to treat lung disease. To highlight this rapidly developing field, the American Journal of Physiology-Lung Cellular and Molecular Physiology is now launching a special Call for Papers on extracellular vesicles in lung health, disease, and therapy. This review aims to set the stage for this call by introducing extracellular vesicles and their emerging roles in lung physiology and pathobiology.

Online Hemodiafiltration Inhibits Inflammation-Related Endothelial Dysfunction and Vascular Calcification of Uremic Patients Modulating miR-223 Expression in Plasma Extracellular Vesicles

Decreased inflammation and cardiovascular mortality are evident in patients with end-stage chronic kidney disease treated by online hemodiafiltration. Extracellular vesicles (EV) are mediators of cell-to-cell communication and contain different RNA types. This study investigated whether mixed online hemodiafiltration (mOL-HDF) beneficial effects associate with changes in the RNA content of plasma EV in chronic kidney disease patients. Thirty bicarbonate hemodialysis (BHD) patients were randomized 1:1 to continue BHD or switch to mOL-HDF. Concentration, size, and microRNA content of plasma EV were evaluated for 9 mo; we then studied EV effects on inflammation, angiogenesis, and apoptosis of endothelial cells (HUVEC) and on osteoblast mineralization of vascular smooth muscle cells (VSMC). mOL-HDF treatment reduced different inflammatory markers, including circulating CRP, IL-6, and NGAL. All hemodialysis patients showed higher plasma levels of endothelial-derived EV than healthy subjects, with no significant differences between BHD and mOL-HDF. However, BHD-derived EV had an increased expression of the proatherogenic miR-223 with respect to healthy subjects or mOL-HDF. Compared with EV from healthy subjects, those from hemodialysis patients reduced angiogenesis and increased HUVEC apoptosis and VSMC calcification; however, all these detrimental effects were reduced with mOL-HDF with respect to BHD. Cell transfection with miR-223 mimic or antagomiR proved the role of this microRNA in EV-induced HUVEC and VSMC dysfunction. The switch from BHD to mOL-HDF significantly reduced systemic inflammation and miR-223 expression in plasma EV, thus improving HUVEC angiogenesis and reducing VSMC calcification.

Platelet-Derived Microparticles: A New Index of Monitoring Platelet Activation and Inflammation in Kawasaki Disease

OBJECTIVE

To investigate the dynamic changes of platelet-derived microparticles (PDMP) in Kawasaki disease (KD) and its clinical significance and to study its relationship with intravenous immunoglobulin (IVIG) resistance, inflammatory indicators and aspirin treatment in children with KD.

METHODS

Twenty children with KD were enrolled as the experimental group, while 20 age- and gender-matched children with common febrile disease were included in the control group. Blood samples were drawn before and 7-10 d after IVIG infusion and thereafter at 1, 2, and 3 mo after the onset of KD to estimate the PDMP concentrations by enzyme linked immunosorbent assay (ELISA). C-reactive protein (hs-CRP), erythrocyte sedimentation rate (ESR), procalcitonin (PCT), and cytokines [Interleukin-6 (IL-6), Tumor necrosis factor-α (TNF-α), and Soluble interleukin-2 (sIL-2R)] were also measured.

RESULTS

The level of PDMP in KD children before IVIG was significantly higher than that in controls (P < 0.0001). The PDMP level in KD children decreased significantly at 7 to 10 d after IVIG (P < 0.0001) and then decreased to the lowest level in the course of 1 to 2 mo. Some children's PDMP level rebounded in the course of 3 mo (P = 0.047). In addition, the mean level of PDMP in IVIG-resistant children was higher than that in IVIG-effective children; however, there was no significant difference between the two groups (P = 0.1945). Furthermore, PDMP was positively correlated with hs-CRP, IL-6, and sIL-2R levels, but no correlation was observed with ESR, PCT, and TNF-α levels.

CONCLUSIONS

PDMP can be used as an index to monitor inflammation in children at the acute stage of KD. And the duration of platelet activation in KD is individualized.