Microparticles and microRNAs: new players in the complex field of coagulation

A comparative study on the haemostatic changes in kidney failure patients: Pre- and post- haemodialysis and haemodiafiltration

BACKGROUND

Individuals with kidney failure have a compromised haemostatic system making them susceptible to both thrombosis and bleeding.

OBJECTIVES

Assessment of primary haemostasis in patients treated with either haemodialysis (HD) or haemodiafiltration (HDF) was performed through the measurement of several coagulation-based tests, both pre- and post-dialysis.

PATIENTS/METHODS

41 renal failure patients and 40 controls were recruited. Platelet aggregometry, Factor XIII (FXIII), Fibrinogen, Von Willebrand Factor (VWF) and Soluble P-Selectin (sP-Sel) levels were measured.

RESULTS

Maximum platelet aggregation was diminished in renal patients irrespective of aspirin intake. Post-dialysis, platelet function was exacerbated. Pre-dialysis FXIII levels were similar to the healthy cohort and became elevated post-dialysis. This elevation could not be explained by the relative decrease of water by dialysis. Fibrinogen levels were already elevated pre-dialysis and further increased post-dialysis. This elevation was associated with the relative decrease of water by dialysis. VWF levels in males were similar to the healthy cohort and became elevated post-dialysis. This elevation was associated with dialysis-related water loss. VWF antigen and activity in female patients were already elevated pre-dialysis and further increased post-dialysis with the exception of VWF activity in HDF treated female patients. sP-Sel levels were lower than those of the healthy cohort and became similar to the healthy cohort post-dialysis. This elevation could not be explained by the relative decrease of water by dialysis.

CONCLUSIONS

Whilst platelet aggregometry was diminished, we noted elevated clotting factors such as fibrinogen, FXIII and VWF with no significant differences between HD and HDF-treated patients.

Anticoagulation in Chronic Kidney Disease

The nuanced landscape of anticoagulation therapy in patients with chronic kidney disease (CKD) presents a formidable challenge, intricately balancing the dual hazards of hemorrhage and thrombosis. These patients find themselves in a precarious position, teetering on the edge of these risks due to compromised platelet functionality and systemic disturbances within their coagulation frameworks. The management of such patients necessitates a meticulous approach to dosing adjustments and vigilant monitoring to navigate the perilous waters of anticoagulant therapy. This is especially critical considering the altered pharmacokinetics in CKD, where the clearance of drugs is significantly impeded, heightening the risk of accumulation and adverse effects. In the evolving narrative of anticoagulation therapy, the introduction of direct oral anticoagulants (DOACs) has heralded a new era, offering a glimmer of hope for those navigating the complexities of CKD. These agents, with their promise of easier management and a reduced need for monitoring, have begun to reshape the contours of care, particularly for patients not yet on dialysis. However, this is not without its caveats. The application of DOACs in the context of advanced CKD remains a largely uncharted territory, necessitating a cautious exploration to unearth their true potential and limitations. Moreover, the advent of innovative strategies such as left atrial appendage occlusion (LAAO) underscores the dynamic nature of anticoagulation therapy, potentially offering a tailored solution for those at the intersection of CKD and elevated stroke risk. Yet the journey toward integrating such advancements into standard practice is laden with unanswered questions, demanding rigorous investigation to illuminate their efficacy and safety across the spectrum of kidney disease. In summary, the management of anticoagulation in CKD is a delicate dance, requiring a harmonious blend of precision, caution, and innovation. As we venture further into this complex domain, we must build upon our current understanding, embracing both emerging therapies and the need for ongoing research. Only then can we hope to offer our patients a path that navigates the narrow strait between bleeding and clotting, toward safer and more effective care.

PBMC MicroRNAs: Promising Biomarkers for the Differential Diagnosis of COVID-19 Patients with Abnormal Coagulation Indices

MicroRNAs, or miRNAs, may involve in coagulation and inflammation pathways caused by severe Coronavirus disease (COVID-19). Accordingly, this attempt was made to explore the behavior of peripheral blood mononuclear cells (PBMCs) miRNAs as effective biomarkers to diagnose COVID-19 patients with normal and abnormal coagulation indices. We selected the targeted miRNAs (miR-19a-3p, miR-223-3p, miR-143-5p, miR-494-3p and miR-301a-5p) according to previous reports, whose PBMC levels were then determined by real-time PCR. Receiver operating characteristic (ROC) curve was obtained to clarify the diagnostic potency of studied miRNAs. The differentially expressed miRNA profiles and corresponding biological activities were predicted in accordance with bioinformatics data. Targeted miRNAs' expression profiles displayed a significant difference between COVID-19 subjects with normal and abnormal coagulation indices. Moreover, the average miR-223-3p level expressed in COVID-19 cases with normal coagulation indices was significantly lower than that in healthy controls. Based on data from ROC analysis, miR-223-3p and miR-494-3p are promising biomarkers to distinguish the COVID-19 cases with normal or abnormal coagulation indices. Bioinformatics data highlighted the prominent role of selected miRNAs in the inflammation and TGF-beta signaling pathway. The differences existed in the expression profiles of selected miRNAs between the groups introduced miR-494-3p and miR-223-3p as potent biomarkers to prognosis the incidence of COVID-19.

The Role of the Coagulation System in Peripheral Arterial Disease: Interactions with the Arterial Wall and Its Vascular Microenvironment and Implications for Rational Therapies

Peripheral artery disease (PAD) is a clinical manifestation of atherosclerotic disease with a large-scale impact on the economy and global health. Despite the role played by platelets in the process of atherogenesis being well recognized, evidence has been increasing on the contribution of the coagulation system to the atherosclerosis formation and PAD development, with important repercussions for the therapeutic approach. Histopathological analysis and some clinical studies conducted on atherosclerotic plaques testify to the existence of different types of plaques. Likely, the role of coagulation in each specific type of plaque can be an important determinant in the histopathological composition of atherosclerosis and in its future stability. In this review, we analyze the molecular contribution of inflammation and the coagulation system on PAD pathogenesis, focusing on molecular similarities and differences between atherogenesis in PAD and coronary artery disease (CAD) and discussing the possible implications for current therapeutic strategies and future perspectives accounting for molecular inflammatory and coagulation targets. Understanding the role of cross-talking between coagulation and inflammation in atherosclerosis genesis and progression could help in choosing the right patients for future dual pathway inhibition strategies, where an antiplatelet agent is combined with an anticoagulant, whose role, despite pathophysiological premises and trials' results, is still under debate.

Circulating microparticles are associated with plaque burden and cause eNOS uncoupling in patients with carotid atherosclerosis

Aims: The study aimed to evaluate the correlation of different microparticle (MP) phenotypes with plaque burden and their diagnostic value and preliminarily explore the role of MPs in atherosclerosis (AS).

Methods: Carotid intima-media thickness (CIMT) and maximal plaque area in 23 patients with carotid atherosclerosis (CAS) and 22 healthy subjects were measured by ultrasound. Transmission electron microscopy, nanoparticle tracking analysis and western blot were used to identify MPs. Flow cytometry assay measured absolute number of MPs, and receiver operating characteristic (ROC) analysis was used to assess the relationship between plaque burden and MPs. To study the preliminary mechanism of MPs in AS, MPs were administered to 32 male Kunming mice, which were randomly divided into control, CAS, healthy, and tetrahydrobiopterin (BH4) groups. Hematoxylin-eosin staining, immunohistochemistry staining, and Western blot were adopted to detect relevant indexes 24 h after the injection.

Results: The plasma levels of CD45+ leukocyte-derived microparticle (LMP), CD11a+ LMP, CD11a+/CD45+ LMP, and CD31+/CD42b+ platelet-derived microparticle (PMP) in CAS patients were significantly higher than those in healthy subjects, and were positively correlated with the maximal plaque area. Moreover, the levels of CD11a+ LMP, CD11a+/CD45+ LMP were also positively correlated with CIMT. The area under the ROC curve of the four MPs was 0.689, 0.747, 0.741, and 0.701, respectively. Compared with healthy subjects, MPs from CAS patients resulted in a significantly lower expression of endothelial nitric oxide synthase (eNOS) dimer/monomer, and BH4 could improve eNOS uncoupling. Moreover, the level of VCAM-1 in intima in the CAS group was significantly higher than in the other three groups.

Conclusion: CD11a+ LMP and CD11a+/CD45+ LMP might be potential biomarkers for CAS prediction. BH4-related eNOS uncoupling occurs in CAS patients, and circulating MPs from them lead to endothelial dysfunction through eNOS uncoupling.

Circulating microparticles as indicators of cardiometabolic risk in PCOS

Polycystic ovary syndrome (PCOS), the most prevalent endocrine disturbance of the female reproductive system, is associated with several pathologic conditions, such as metabolic syndrome, obesity, diabetes, dyslipidemia, and insulin resistance, all of which are tightly connected to its progression. These factors are associated with a type of extracellular vesicle, ie, microparticles (MPs), released by shedding due to cell activation and apoptosis. Circulating MPs (cMPs) are secreted by a variety of cells, such as platelets, endothelial, leukocytes, and erythrocytes, and contain cytoplasmic substances derived from parent cells that account for their biologic activity. Current evidence has clearly shown that increased cMPs contribute to endothelial dysfunction, diabetes, hypertriglyceridemia, metabolic syndrome, cardiovascular abnormalities as well as PCOS. It has also been reported that platelet and endothelial MPs are specifically increased in PCOS thus endangering vascular health and subsequent cardiovascular disease. Given the importance of cMPs in the pathophysiology of PCOS, we review the role of cMPs in PCOS with a special focus on cardiometabolic significance.

RNA-seq analysis of extracellular vesicles from hyperphosphatemia-stimulated endothelial cells provides insight into the mechanism underlying vascular calcification

Background

Hyperphosphatemia (HP) is associated with vascular calcification (VC) in chronic kidney disease (CKD). However, relationship between HP-induced-endothelial extracellular vesicles (HP-EC-EVs) and VC is unclear, and miR expression in HP-EC-EVs has not been determined.

Methods

We isolated HP-EC-EVs from endothelial cells with HP and observed that HP-EC-EVs were up-taken by vascular smooth muscle cells (VSMCs). HP-EC-EVs inducing calcium deposition was characterized by Alizarin Red S, colourimetric analysis and ALP activity. To investigate the mechanism of HP-EC-EVs-induced VSMC calcification, RNA-sequencing for HP-EC-EVs was performed.

Results

We first demonstrated that HP-EC-EVs induced VSMC calcification in vitro. RNA-seq analysis of HP-EC-EVs illustrated that one known miR (hsa-miR-3182) was statistically up-regulated and twelve miRs were significantly down-regulated, which was verified by qRT-PCR. We predicted 58,209 and 74,469 target genes for those down- and up-regulated miRs respectively through miRDB, miRWalk and miRanda databases. GO terms showed that down- and up-regulated targets were mostly enriched in calcium-dependent cell–cell adhesion via plama membrane cell-adhesion molecules (GO:0,016,338, BP) and cell adhesion (GO:0,007,155, BP), plasma membrane (GO:0,005,886, CC), and metal ion binding (GO:0,046,914, MF) and ATP binding (GO:0,005,524, MF) respectively. Top-20 pathways by KEGG analysis included calcium signaling pathway, cAMP signaling pathway, and ABC transporters, which were closely related to VC.

Conclusion

Our results indicated that those significantly altered miRs, which were packaged in HP-EC-EVs, may play an important role in VC by regulating related pathways. It may provide novel insight into the mechanism of CKD calcification.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02823-6.

Venous thromboembolic complications in patients with chronic kidney disease: prevalence and features of drug treatment

The article is an opinion on the problem of venous thromboembolic (VTE) complications in patients with chronic kidney disease (CKD), which is significant and urgent for Russia. Signs of CKD are noted in more than 1/3 of patients with chronic heart failure; a decrease in kidney function is observed in 36% of people over the age of 60, in people of working age, a decrease in function is noted in 16% of cases, and in the presence of cardiovascular diseases increases to 26%. Clinical research data convincingly show that CKD is an independent risk factor for the development of VTE complications. The last decade has given us the opportunity to observe a kind of "revolution" in VTE therapy, which is associated with the appearance on the market of direct oral anticoagulants, including inhibitors of factor IIa (thrombin) and factor Xa. These drugs are approved by the Food and Drug Administration for the treatment of acute thromboembolism. Nevertheless, patients with severe CKD (estimated glomerular filtration rate 30 ml/min) are still limited to the use of unfractionated heparin and vitamin K antagonists, as there is insufficient data to support the use of direct oral anticoagulants in this population.

The role of sleep disorders in cardiovascular diseases: Culprit or accomplice?

Sleep disorders frequently comorbid with several cardiovascular diseases (CVDs), attracting increasing scientific attention and interest. Sleep disorders include insomnia, sleep-disordered breathing, restless legs syndrome, etc. It is well known that inflammation, sympathetic activation, and endothelial dysfunction play critical roles in sleep disorders, all of which are predisposing factors for CVDs. The comorbidity of sleep disorders and CVDs may have a bidirectional relationship. Patients with CVDs may have a high incidence of sleep disorders and vice versa. This review focused on the comorbidity of sleep disorders and CVDs and discussed the potential pathophysiological mechanisms and therapeutic strategies. In addition to the existing mechanisms, this review summarized novel potential mechanisms underlying comorbidities, such as gut microbiota, orexin, and extracellular vesicles, which may provide a theoretical basis for further basic research and clinical investigations on improving therapeutic outcomes.

An Ex Vivo and In Silico Study Providing Insights into the Interplay of Circulating miRNAs Level, Platelet Reactivity and Thrombin Generation: Looking beyond Traditional Pharmacogenetics

Platelet reactivity (PR), a key pharmacodynamic (PD) component of the action of antiplatelet drugs in cardiovascular disease (CVD) patients, is highly variable. PR is associated with occurrence or recurrence of thrombotic and bleeding events, but this association is modulated by several factors. Conventional pharmacogenetics explains a minor part of this PR variability, and among determinants of PR, circulating microRNAs (miRNAs) have been the focus of attention during these last years as biomarkers to predict PR and clinical outcomes in CVD. This being said, the impact of miRNAs on platelet function and the mechanisms behind it are largely unknown. The level of a set of candidate miRNAs including miR-126-3p, miR-150-5p, miR-204-5p and miR-223-3p was quantified in plasma samples of stable CVD patients and correlated with PR as assessed by light-transmission aggregometry and in vivo thrombin generation markers. Finally, miRNA target networks were built based on genes involved in platelet function. We show that all candidate miRNAs were associated with platelet aggregation, while only miR-126-3p and miR-223-3p were positively correlated with in vivo thrombin generation markers. In silico analysis identified putative miRNA targets involved in platelet function regulation. Circulating miRNAs were associated with different aspects of platelet reactivity, including platelet aggregation and platelet-supported thrombin generation. This paves the way to a personalized antithrombotic treatment according to miRNA profile in CVD patients.

Methods to Investigate miRNA Function: Focus on Platelet Reactivity

MicroRNAs (miRNAs) are small noncoding RNAs modulating protein production. They are key players in regulation of cell function and are considered as biomarkers in several diseases. The identification of the proteins they regulate, and their impact on cell physiology, may delineate their role as diagnostic or prognostic markers and identify new therapeutic strategies. During the last 3 decades, development of a large panel of techniques has given rise to multiple models dedicated to the study of miRNAs. Since plasma samples are easily accessible, circulating miRNAs can be studied in clinical trials. To quantify miRNAs in numerous plasma samples, the choice of extraction and purification techniques, as well as normalization procedures, are important for comparisons of miRNA levels in populations and over time. Recent advances in bioinformatics provide tools to identify putative miRNAs targets that can then be validated with dedicated assays. In vitro and in vivo approaches aim to functionally validate candidate miRNAs from correlations and to understand their impact on cellular processes. This review describes the advantages and pitfalls of the available techniques for translational research to study miRNAs with a focus on their role in regulating platelet reactivity.

The Role of Epigenetics in the Regulation of Hemostatic Balance

Epigenetics, a term conventionally used to explain the intricate interplay between genes and the environment, is now regarded as the fundament of developmental biology. Several lines of evidence garnered over the past decades suggest that epigenetic alterations, mostly encompassing DNA methylation, histone tail modifications, and generation of microRNAs, play an important, though still incompletely explored, role in both primary and secondary hemostasis. Epigenetic variations may interplay with platelet functions and their responsiveness to antiplatelet drugs, and they may also exert a substantial contribution in modulating the production and release into the bloodstream of proteins involved in blood coagulation and fibrinolysis. This emerging evidence may have substantial biological and clinical implications. An enhanced understanding of posttranscriptional mechanisms would help to clarify some remaining enigmatic issues in primary and secondary hemostasis, which cannot be thoughtfully explained by genetics or biochemistry alone. Increased understanding would also pave the way to developing innovative tests for better assessment of individual risk of bleeding or thrombosis. The accurate recognition of key epigenetic mechanisms in hemostasis would then contribute to identify new putative therapeutic targets, and develop innovative agents that could be helpful for preventing or managing a vast array of hemostasis disturbances.

Extracellular vesicles released from p18 overexpressing pulmonary endothelial cells are barrier protective - potential implications for acute respiratory distress syndrome

The novel endosome protein, p18, and the early endosome GTPase, Rab4, play a significant role in protecting the pulmonary vasculature against permeability associated with acute respiratory distress syndrome. Recently, endothelial-derived extracellular vesicles have been identified to play a key role in the endothelial permeability associated with acute respiratory distress syndrome. Therefore, we investigated the effect of these microparticles, released from endothelial cells overexpressing p18 and Rab4, on pulmonary endothelial barrier function. Endothelial-derived extracellular vesicles isolated from lung microvascular endothelial cells which overexpressed cDNA for wild-type p18 protected a naïve monolayer against lipopolysaccharide-induced permeability. In contrast, endothelial-derived extracellular vesicles from cells overexpressing the non-endosomal binding p18 mutant (p18^N39) exerted no protective effect on the endothelial monolayer. Cells overexpressing either dominant active or inactive Rab4 released endothelial-derived extracellular vesicles which had no effect on lipopolysaccharide-induced permeability. miRNA analysis and permeability studies of endothelial-derived extracellular vesicle isolated from wild-type p18-overexpressing cells demonstrates that let-7i-5p, miR-96-5p, and miR-137-3p are endothelial-derived extracellular vesicle cargo which exert protective effects on the pulmonary endothelium. Finally, we observed down-regulation of p18 protein expression in both the lung and endothelium in an in vivo and in vitro model of acute respiratory distress syndrome. These results demonstrate that endothelial-derived extracellular vesicle released from cells overexpressing p18, but not Rab4, contain miRNA cargo which likely promote a barrier-protective effect on the pulmonary endothelium in settings of acute respiratory distress syndrome. Findings indicate the importance of p18 in the pulmonary vasculature and demonstrate that targeting this protein may provide a novel therapeutic strategy to reduce endothelial permeability associated with acute respiratory distress syndrome.

The Role of MicroRNAs in Regulating Cytokines and Growth Factors in Coronary Artery Disease: The Ins and Outs

Coronary artery diseases (CAD), as a leading cause of mortality around the world, has attracted the researchers' attention for years to find out its underlying mechanisms and causes. Among the various key players in the pathogenesis of CAD cytokines, microRNAs (miRNAs) are crucial. In this study, besides providing a comprehensive overview of the involvement of cytokines, growth factors, and miRNAs in CAD, the interplay between miRNA with cytokine or growth factors during the development of CAD is discussed.

Microparticles (Exosomes) and Atherosclerosis

PURPOSE OF REVIEW

This review summarizes the effects of microparticles and exosomes in the progression of atherosclerosis and the prospect for their diagnostic and therapeutic potentials.

RECENT FINDINGS

Microparticles and exosomes can induce endothelial dysfunction, vascular inflammation, coagulation, thrombosis, and calcification via their components of proteins and noncoding RNAs, which may promote the progression of atherosclerosis. The applications of microparticles and exosomes become the spotlight of clinical diagnosis and therapy. Microparticles and exosomes are members of extracellular vesicles, which are generated in various cell types by different mechanisms of cell membrane budding and multivesicular body secretion, respectively. They are important physiologic pathways of cell-to-cell communication in vivo and act as messengers accelerating or alleviating the process of atherosclerosis. Microparticles and exosomes may become diagnostic biomarkers and therapeutic approaches of atherosclerosis.

Circulating MicroRNA Profiling in Non-ST Elevated Coronary Artery Syndrome Highlights Genomic Associations with Serial Platelet Reactivity Measurements

Changes in platelet physiology are associated with simultaneous changes in microRNA concentrations, suggesting a role for microRNA in platelet regulation. Here we investigated potential associations between microRNA and platelet reactivity (PR), a marker of platelet function, in two cohorts following a non-ST elevation acute coronary syndrome (NSTE-ACS) event. First, non-targeted microRNA concentrations and PR were compared in a case (N = 77) control (N = 76) cohort within the larger TRILOGY-ACS trial. MicroRNA significant in this analysis plus CVD-associated microRNAs from the literature were then quantified by targeted rt-PCR in the complete TRILOGY-ACS cohort (N = 878) and compared with matched PR samples. Finally, microRNA significant in the non-targeted & targeted analyses were verified in an independent post NSTE-ACS cohort (N = 96). From the non-targeted analysis, 14 microRNAs were associated with PR (Fold Change: 0.91–1.27, p-value: 0.004–0.05). From the targeted analysis, five microRNAs were associated with PR (Beta: −0.09–0.22, p-value: 0.004–0.05). Of the 19 significant microRNAs, three, miR-15b-5p, miR-93 and miR-126, were consistently associated with PR in the TRILOGY-ACS and independent Singapore post-ACS cohorts, suggesting the measurement of circulating microRNA concentrations may report on dynamic changes in platelet biology following a cardiovascular ischemic event.

Circulating MiRNA-195-5p and -451a in Transient and Acute Ischemic Stroke Patients in an Emergency Department

We have evaluated circulating miRNAs (-195-5p and -451a) in subjects with acute ischemic stroke (AIS) and in patients with transient ischemic attack (TIA). In this study, 18 subjects with AIS and 18 patients with TIA were enrolled and examined at admission (T0) and at 24 h and 48 h after admission, and compared to 20 controls (C). At T0, circulating miRNA-195-5p and -451a were significantly upregulated in both AIS and TIA patients, compared to C. We also observed a progressive reduction of circulating miRNA levels at 24 h and 48 h in both AIS and TIA patients. Hypoxia inducible factor 1alpha (HIF-1α) serum level was significantly increased at T0, in both AIS and TIA patients, in comparison to C (both p < 0.01 vs. C) and it decreased in both AIS and TIA patients at 24 h and at 48 h, in comparison to T0 (both p < 0.01 vs. T0). Vascular endothelial growth factor (VEGF) serum level was significantly decreased at T0, in both AIS and TIA patients, if compared to C (both p < 0.01 vs. C) and increased, in both AIS and TIA patients, at 24 h and 48 h, if compared to T0 (both p < 0.01 vs. T0). The elevated expression of miRNA-195-5p and miRNA-451a significantly decreased over time at 24 h and 48 h, and it is associated with decreased HIF-α levels and increased VEGF serum levels. These data may suggest a role for this miRNAs as biomarker in the pathogenesis and prognosis of AIS patients and for the first time also in TIA patients.

Association study of miR-146a, miR-149, miR-196a2, and miR-499 polymorphisms with venous thromboembolism in a Korean population

Despite much progress in microRNA (miRNA) research, information regarding the association between miRNAs and venous thromboembolism (VTE), especially in Asian patients, remains limited. This case-control study sought to determine the correlation between the presence of polymorphisms in the genes encoding the miRNAs miR-146a, miR-149, miR-196a2, miR-499, and VTE in Korean patients. We observed no statistically significant differences in the genotype frequency of miRNA polymorphisms between 300 control individuals and 203 VTE patients. However, we observed a significant association between three allelic combinations of miRNA polymorphisms and VTE risk. Overall, our findings suggest that specific miRNA polymorphisms are associated with the risk of VTE in a Korean population.

New insights into the mechanisms of pulmonary edema in acute lung injury

Appearance of alveolar protein-rich edema is an early event in the development of acute respiratory distress syndrome (ARDS). Alveolar edema in ARDS results from a significant increase in the permeability of the alveolar epithelial barrier, and represents one of the main factors that contribute to the hypoxemia in these patients. Damage of the alveolar epithelium is considered a major mechanism responsible for the increased pulmonary permeability, which results in edema fluid containing high concentrations of extravasated macromolecules in the alveoli. The breakdown of the alveolar-epithelial barrier is a consequence of multiple factors that include dysregulated inflammation, intense leukocyte infiltration, activation of pro-coagulant processes, cell death and mechanical stretch. The disruption of tight junction (TJ) complexes at the lateral contact of epithelial cells, the loss of contact between epithelial cells and extracellular matrix (ECM), and relevant changes in the communication between epithelial and immune cells, are deleterious alterations that mediate the disruption of the alveolar epithelial barrier and thereby the formation of lung edema in ARDS.

[Vascular dysfunction in obstructive sleep apnoea: Implication of microparticules]

Obstructive sleep apnea (OSA) is associated with increased cardiovascular diseases, including myocardial infarction and stroke and promotes cardiovascular risk factors including diabetes and hypertension. OSA has also been proposed to have a direct proatherogenic effects. Recent studies have investigated the role of microparticles (MPs) in the atherogenic process. MPs are small plasma membrane vesicles that can be released by a variety of vascular or blood cells and that contain membrane and cytosolic elements. Case-control studies have suggested that OSA is associated with an increase in circulating platelet-, endothelial- and leukocyte-derived MPs. MPs from OSA patients injected to mice have also been shown to induce vascular inflammation and endothelial dysfunction. In this article, we provide an overview of the main characteristics of MPs expressed in OSA and their potential role in the atherogenic process.

Different impact of aspirin on renal progression in patients with predialysis advanced chronic kidney disease with or without previous stroke

BACKGROUND

The benefit of reducing the risk of stroke against increasing the risk of renal progression associated with antiplatelet therapy in patients with advanced chronic kidney disease (CKD) is controversial.

METHODS

We enrolled 1301 adult patients with advanced CKD treated with erythropoiesis stimulating agents from January 1, 2002 to June 30, 2009 from the 2005 Longitudinal Health Insurance Database in Taiwan. All of the patients were followed until the development of the primary or secondary endpoints, or the end of the study (December 31, 2011). The primary endpoint was the development of ischemic stroke, and the secondary endpoints included hospitalization for bleeding events, cardiovascular mortality, all-cause mortality, and renal failure. The adjusted cumulative probability of events was calculated using multivariate Cox proportional regression analysis.

RESULTS

Adjusted survival curves showed that the usage of aspirin was not associated with ischemic stroke, hospitalization for bleeding events, cardiovascular mortality or all-cause mortality, however, it was significantly associated with renal failure. In subgroup analysis, aspirin use was associated with renal failure in the patients with no history of stroke (HR, 1.41; 95% CI, 1.14-1.73), and there was a borderline interaction between previous stroke and the use of aspirin on renal failure (interaction p=0.0565).

CONCLUSIONS

There was no significant benefit in preventing ischemic stroke in the patients with advanced CKD who received aspirin therapy. Furthermore, the use of aspirin was associated with the risk of renal failure in the patients with advanced CKD without previous stroke.

Biological basis of personalized anticoagulation in cancer: oncogene and oncomir networks as putative regulators of coagulopathy

Activation of stromal response pathways in cancer is increasingly viewed as both a local and systemic extension of molecular alterations driving malignant transformation. Rather than reflecting passive and unspecific responses to anatomical abnormalities, the coagulation system is a target of oncogenic deregulation, impacting the role of clotting and fibrinolytic proteins, and integrating hemostasis, inflammation, angiogenesis and cellular growth effects in cancer. These processes signify, but do not depend on, the clinically manifest coagulopathy and thrombosis. In this regard, the role of driver mutations affecting oncoprotein coding genes such as RAS, EGFR or MET and tumour suppressors (PTEN, TP53) are well described as regulators of tissue factor (TF), protease activated receptors (PAR-1/2) and ectopic coagulation factors (FVII). Indeed, in both adult and pediatric brain tumours the expression patterns of coagulation and angiogenesis regulators (coagulome and angiome, respectively) reflect the molecular subtypes of the underlying diseases (glioblastoma or medulloblastoma) as defined by their oncogenic classifiers and clinical course. This emerging understanding is still poorly established in relation to the transforming effects of non-coding genes, including those responsible for the expression of microRNA (miR). Indeed, several miRs have been recently found to regulate TF and other effectors. We recently documented that in the context of the aggressive embryonal tumour with multilayered rosettes (ETMR) the oncogenic driver miR (miR-520g) suppresses the expression of TF and correlates with hypocoagulant tumour characteristics. Unlike in adult cancers, the growth of pediatric embryonal brain tumour cells as spheres (to maintain stem cell properties) results in upregulation of miR-520g and downregulation of TF expression and activity. We postulate that oncogenic protein and miR coding genes form alternative pathways of coagulation system regulation in different tumour settings, a property necessitating more personalised and biologically-based approaches to anticoagulation.

Lectin-Based Characterization of Vascular Cell Microparticle Glycocalyx

Microparticles (MPs) are released constitutively and from activated cells. MPs play significant roles in vascular homeostasis, injury, and as biomarkers. The unique glycocalyx on the membrane of cells has frequently been exploited to identify specific cell types, however the glycocalyx of the MPs has yet to be defined. Thus, we sought to determine whether MPs, released both constitutively and during injury, from vascular cells have a glycocalyx matching those of the parental cell type to provide information on MP origin. For these studies we used rat pulmonary microvascular and artery endothelium, pulmonary smooth muscle, and aortic endothelial cells. MPs were collected from healthy or cigarette smoke injured cells and analyzed with a panel of lectins for specific glycocalyx linkages. Intriguingly, we determined that the MPs released either constitutively or stimulated by CSE injury did not express the same glycocalyx of the parent cells. Further, the glycocalyx was not unique to any of the specific cell types studied. These data suggest that MPs from both normal and healthy vascular cells do not share the parental cell glycocalyx makeup.

microRNA expression in peripheral blood cells following acute ischemic stroke and their predicted gene targets

Background

microRNA (miRNA) are important regulators of gene expression. In patients with ischemic stroke we have previously shown that differences in immune cell gene expression are present. In this study we sought to determine the miRNA that are differentially expressed in peripheral blood cells of patients with acute ischemic stroke and thus may regulate immune cell gene expression.

Methods

miRNA from peripheral blood cells of forty-eight patients with ischemic stroke and vascular risk factor controls were compared. Differentially expressed miRNA in patients with ischemic stroke were determined by microarray with qRT-PCR confirmation. The gene targets and pathways associated with ischemic stroke that may be regulated by the identified miRNA were characterized.

Results

In patients with acute ischemic stroke, miR-122, miR-148a, let-7i, miR-19a, miR-320d, miR-4429 were decreased and miR-363, miR-487b were increased compared to vascular risk factor controls. These miRNA are predicted to regulate several genes in pathways previously identified by gene expression analyses, including toll-like receptor signaling, NF-κβ signaling, leukocyte extravasation signaling, and the prothrombin activation pathway.

Conclusions

Several miRNA are differentially expressed in blood cells of patients with acute ischemic stroke. These miRNA may regulate leukocyte gene expression in ischemic stroke including pathways involved in immune activation, leukocyte extravasation and thrombosis.