Endothelial Barrier and Its Abnormalities in Cardiovascular Disease

Rosmarinic acid downregulates the oxLDL‑induced interaction between monocytes and endothelial cells, in addition to monocyte diapedesis, under high glucose conditions

Endothelial dysfunction during diabetes has been previously reported to be at least in part attributed to increased oxidized low‑density lipoprotein (oxLDL) levels mediated by high glucose (HG) levels. Endothelial inflammation increases the adhesiveness of monocytes to the endothelium in addition to increasing vascular permeability, promoting diabetic atherogenesis. In a previous study, it was reported that oxLDL treatment induced nucleotide‑binding domain and leucine‑rich repeat containing family, pyrin domain‑containing 3 inflammasome activation in endothelial cells (ECs) under HG conditions, in a manner that could be effectively reversed by rosmarinic acid. However, it remains unclear whether oxLDL‑mediated inflammasome activation can regulate the interaction between monocytes and ECs. The effects of oxLDL‑mediated inflammasome activation on endothelial permeability under HG conditions, in addition to the effects of rosmarinic acid on these oxLDL‑mediated processes, also remain poorly understood. Therefore, the present study aimed to elucidate the mechanisms involved in oxLDL‑induced endothelial permeability and monocyte diapedesis under HG conditions, in addition to the potential effects of rosmarinic acid. ECs were treated with oxLDL under HG conditions in the presence or absence of ROS scavengers mitoTEMPO and NAC, p38 inhibitor SB203580, FOXO1 inhibitor AS1842856 or transfected with the TXNIP siRNA, before protein expression levels of intercellular adhesion molecule 1 (ICAM‑1), vascular cell adhesion molecule‑1 (VCAM‑1), phosphorylated vascular endothelial‑cadherin (VE‑cadhedrin), VE‑cadherin and zonula occludens‑1 (ZO‑1) were measured by western blotting. In addition, adhesion assay and Transwell assays were performed. oxLDL was found to significantly increase the expression of ICAM‑1 and VCAM‑1 in ECs under HG conditions whilst also enhancing the adhesion of monocytes to ECs. This was found to be dependent on the reactive oxygen species (ROS)/p38 MAPK/forkhead box O1 (FOXO1)/thioredoxin interacting protein (TXNIP) signaling pathway. In addition, oxLDL‑stimulated ECs under HG conditions exhibited increased phosphorylated VE‑cadherin protein levels and decreased ZO‑1 protein expression levels compared with those in untreated ECs, suggesting increased endothelial permeability. Furthermore, monocyte transmigration through the endothelial monolayer was significantly increased by oxLDL treatment under HG conditions. These oxLDL‑mediated effects under HG conditions were also demonstrated to be dependent on this ROS/p38 MAPK/FOXO1/TXNIP signaling pathway. Subsequently, rosmarinic acid treatment significantly reversed oxLDL‑induced overexpression of adhesion molecules and monocyte‑EC adhesion, oxLDL‑induced endothelial junction hyperpermeability and monocyte transmigration through the endothelial monolayer under HG conditions, in a dose‑dependent manner. These results suggest that rosmarinic acid can exert a protective effect against oxLDL‑mediated endothelial dysfunction under HG conditions by reducing the interaction between monocytes and ECs in addition to preventing monocyte diapedesis.

Isoflavones from Semen Sojae Preparatum Improve Atherosclerosis and Oxidative Stress by Modulating Nrf2 Signaling Pathway through Estrogen-Like Effects

Atherosclerosis (AS) often occurs in cardiovascular disease, which is a chronic vascular disease and is harmful to human health. Oxidative stress is involved in its etiology. This study aimed to determine the effectiveness of Isoflavones from semen sojae preparatum (ISSP) in inhibiting oxidative stress and its important molecular mechanisms through in vivo and in vitro experiments. ApoE^−/− mice were used to establish atherosclerosis models through a high-fat diet, and endothelial cells were used to establish oxidative stress injury models through ox-LDL induction. The degree of oxidative stress damage was assessed by detecting changes in ET-1, LDH, SOD, and MDA indicators. It was observed that after ISSP treatment, the oxidative stress damage of mice and endothelial cells was improved. The Nrf2/AER signaling pathway is an important antioxidant pathway that has attracted our attention. Western blotting and qRT-PCR were used to detect the expression of Nrf2, HO-1, and NQO1 in mice aortae and endothelial cells. The results showed that the Nrf2 signaling pathway was activated after ISSP intervention. In addition, in this study, after preantagonizing the estrogen receptors GPR30 and ERβ, it was observed that the effects of ISSP in treating endothelial cell oxidative damage and activating the Nrf2 signaling pathway were weakened. After silencing Nrf2 by Nrf2-siRNA transfection, the effect of ISSP in treating endothelial cell oxidative damage was inhibited. This study shows that ISSP may reduce oxidative stress damage and atherosclerosis through the Nrf2 signaling pathway, and this effect may involve the GPR30 and ERβ estrogen receptors.

Reducing the Damage of Ox-LDL/LOX-1 Pathway to Vascular Endothelial Barrier Can Inhibit Atherosclerosis

Aim

The destruction of the vascular endothelial barrier mediated by Ox-LDL is the initial link to atherosclerosis. Here, we aimed to determine whether the immunological intervention with Ox-ApoB polypeptide fragment (Ox-ApoB-PF) can block the deposition of Ox-LDL in vascular endothelial cells through LOX-1 receptors, thereby protecting the barrier function and survival status of vascular endothelial cells and inhibiting the progression of atherosclerosis.

Methods and Results

In order to determine the harm of Ox-LDL to vascular endothelial cells and the protective effect of immune intervention with Ox-ApoB-PF, we conducted a series of corresponding experiments in vitro and in vivo. The in vitro results showed that Ox-LDL can activate endothelial cell apoptosis pathway; reduce the expression of endothelial junction proteins; affect the migration, deformation, and forming ability; and ultimately destroy the vascular endothelial barrier function. The increased permeability of endothelial cells led to a sharp increase in the phagocytosis of Ox-LDL by macrophages under the endothelial layer. Meanwhile, Ox-LDL stimulation induced a significant upregulation of LOX-1 in endothelial cells and increased the expression of endothelial cell chemokines and adhesion factors. Ox-ApoB-PF antibodies can significantly reduce the abovementioned harmful effects. The in vivo results showed that active immune intervention through Ox-ApoB-PF can protect the endothelial barrier function; reduce macrophage deposition and the inflammatory response in plaques; alleviate lipid deposition in the plaques, as well as apoptosis and necrosis; and increase the ability of liver macrophages to clear Ox-LDL. Eventually, the progression of plaque and the formation of necrotic cores in plaques can be inhibited.

Conclusions

An Ox-ApoB-PF antibody may protect the endothelial cell physiological function and survival status by blocking the combination of Ox-LDL/LOX-1 in vascular endothelial cells. Immune intervention with Ox-ApoB-PF inhibits the occurrence and development of atherosclerotic lesions by protecting the vascular endothelial barrier function.

Angiopoietins as Prognostic Markers for Future Kidney Disease and Heart Failure Events after Acute Kidney Injury

BACKGROUND

The mechanisms underlying long-term sequelae after AKI remain unclear. Vessel instability, an early response to endothelial injury, may reflect a shared mechanism and early trigger for CKD and heart failure.

METHODS

To investigate whether plasma angiopoietins, markers of vessel homeostasis, are associated with CKD progression and heart failure admissions after hospitalization in patients with and without AKI, we conducted a prospective cohort study to analyze the balance between angiopoietin-1 (Angpt-1), which maintains vessel stability, and angiopoietin-2 (Angpt-2), which increases vessel destabilization. Three months after discharge, we evaluated the associations between angiopoietins and development of the primary outcomes of CKD progression and heart failure and the secondary outcome of all-cause mortality 3 months after discharge or later.

RESULTS

Median age for the 1503 participants was 65.8 years; 746 (50%) had AKI. Compared with the lowest quartile, the highest quartile of the Angpt-1:Angpt-2 ratio was associated with 72% lower risk of CKD progression (adjusted hazard ratio [aHR], 0.28; 95% confidence interval [CI], 0.15 to 0.51), 94% lower risk of heart failure (aHR, 0.06; 95% CI, 0.02 to 0.15), and 82% lower risk of mortality (aHR, 0.18; 95% CI, 0.09 to 0.35) for those with AKI. Among those without AKI, the highest quartile of Angpt-1:Angpt-2 ratio was associated with 71% lower risk of heart failure (aHR, 0.29; 95% CI, 0.12 to 0.69) and 68% less mortality (aHR, 0.32; 95% CI, 0.15 to 0.68). There were no associations with CKD progression.

CONCLUSIONS

A higher Angpt-1:Angpt-2 ratio was strongly associated with less CKD progression, heart failure, and mortality in the setting of AKI.

Lipid-Laden Macrophages and Inflammation in Atherosclerosis and Cancer: An Integrative View

Atherosclerotic arterial plaques and malignant solid tumors contain macrophages, which participate in anaerobic metabolism, acidosis, and inflammatory processes inherent in the development of either disease. The tissue-resident macrophage populations originate from precursor cells derived from the yolk sac and from circulating bone marrow-derived monocytes. In the tissues, they differentiate into varying functional phenotypes in response to local microenvironmental stimulation. Broadly categorized, the macrophages are activated to polarize into proinflammatory M1 and anti-inflammatory M2 phenotypes; yet, noticeable plasticity allows them to dynamically shift between several distinct functional subtypes. In atherosclerosis, low-density lipoprotein (LDL)-derived cholesterol accumulates within macrophages as cytoplasmic lipid droplets thereby generating macrophage foam cells, which are involved in all steps of atherosclerosis. The conversion of macrophages into foam cells may suppress the expression of given proinflammatory genes and thereby initiate their transcriptional reprogramming toward an anti-inflammatory phenotype. In this particular sense, foam cell formation can be considered anti-atherogenic. The tumor-associated macrophages (TAMs) may become polarized into anti-tumoral M1 and pro-tumoral M2 phenotypes. Mechanistically, the TAMs can regulate the survival and proliferation of the surrounding cancer cells and participate in various aspects of tumor formation, progression, and metastasis. The TAMs may accumulate lipids, but their type and their specific roles in tumorigenesis are still poorly understood. Here, we discuss how the phenotypic and functional plasticity of macrophages allows their multifunctional response to the distinct microenvironments in developing atherosclerotic lesions and in developing malignant tumors. We also discuss how the inflammatory reactions of the macrophages may influence the development of atherosclerotic plaques and malignant tumors, and highlight the potential therapeutic effects of targeting lipid-laden macrophages in either disease.

Piceatannol alleviates glucolipotoxicity induced vascular barrier injury through inhibition of the ROS/NF-kappa B signaling pathway

Vascular barrier dysfunction is considered as the initial and critical event in atherosclerosis progression. Recent studies have revealed that treatment with piceatannol (PIC) alleviates both acute and chronic responses to vascular injury. We investigated whether PIC treatment would have beneficial effects on glucolipotoxicity-induced endothelial barrier dysfunction. Target proteins of PIC were identified from several online databases. Then, we confirmed the effect of PIC on endothelial barrier function. PIC treatment mitigated the impairment of endothelial cell motility, adhesion and migration ability associated with high glucose/lipid stimulation. PIC stabilized cytoskeletal reorganization and expression of cell cytoskeletal associated proteins GTPase. PIC reversed changes in critical vascular junction proteins and thus preserved endothelial barrier function and permeability. Finally, we confirmed that reducing of nuclear factor kappa B (NF-κB)/p65 activation and elimination of reactive oxygen species (ROS) were involved in the protective effect of PIC against glucolipotoxicity-induced vascular barrier injury. We identify PIC as a promising therapeutic strategy for glucolipotoxicity-induced endothelial barrier injury.

Bioactive components to inhibit foam cell formation in atherosclerosis

BACKGROUND

The production of lipid-laden cells in macrophages after significant ingestion of oxidized low-density lipoprotein is considered the most critical phase in the creation of atherosclerotic lesions, which is known as foam cell formation. Targeting foam cell development to find a potential therapeutic strategy for the management of atherosclerosis has yielded numerous promising outcomes. Multiple variables influence foam cell growth, including scavenger receptor expression, cholesterol transporter expression acyl CoA: cholesterol acyltransferase activity, and neutral cholesteryl ester hydrolase activity. Plants used during herbal therapy have been shown to assist with a variety of ailments.

RESULT

In this study, we found medicinal plants and their bioactive components suppress foam cell formation in a variety of ways; some inhibit cholesterol transporter and lectin-like oxidized low-density lipoprotein receptor-1 upregulation, while others inhibit the function of acyl CoA: cholesterol acyltransferase activity, and neutral cholesteryl ester hydrolase activity.

CONCLUSION

Recent study findings related to the synthesis of the new active component from plant sources by focusing on the typical process involved in the generation of foam cells. We're also looking at using a cellular target-based therapeutic approach to generate novel plant-based medications for the cure of atherosclerosis.

Vascular Function in Patients After Myocardial Infarction: The Importance of Physical Activity

Background: Patients after myocardial infarction have impaired vascular function. However, effects of lifestyle, e.g., physical activity level, on endothelial function and arterial stiffness remain scarce. The aim of our study was to investigate effects of physical activity level and risk factors on endothelial function and arterial stiffness.

Methods: In this cross-sectional study, we ultrasonographically assessed parameters of vascular function, namely flow mediated dilation (FMD) of the brachial artery and carotid artery stiffness in patients after myocardial infarction referred to the cardiac rehabilitation. The International Physical Activity Questionnaire (IPAQ) was obtained from all participants. Based on the IPAQ, patients were classified into three groups: vigorous, moderate, and low physical activity engagement. ANOVA was used for comparison among three groups using Bonferroni correction to determine differences between two sub-groups.

Results: One hundred and eight patients after myocardial infarction (mean age 53 ± 10 years) were included. There were significant differences in terms of FMD (8.2 vs. 4.2 vs. 1.9%, p < 0.001) and pulse wave velocity (PWV), a measure of arterial stiffness (6.1 vs. 6.4 vs. 6.9 m/s, p = 0.004) among groups of vigorous, moderate, and low physical activity engagement, respectively. However, in younger patients only FMD remained associated with physical activity level, while arterial stiffness was not. Low physical activity engagement was a significant predictor of both FMD and PWV in univariate and multivariate models, adjusted for age, sex, and other risk factors.

Conclusion: Low physical activity level is associated with impaired endothelial function and increased arterial stiffness in patients after myocardial infarction. Future studies are warranted to address this issue in a context of cardiac rehabilitation protocols optimization in order to improve vascular function in these patients.

Two-stage degradation and novel functional endothelium characteristics of a 3-D printed bioresorbable scaffold

Bioresorbable scaffolds have emerged as a new generation of vascular implants for the treatment of atherosclerosis, and designed to provide a temporary scaffold that is subsequently absorbed by blood vessels over time. Presently, there is insufficient data on the biological and mechanical responses of blood vessels accompanied by bioresorbable scaffolds (BRS) degradation. Therefore, it is necessary to investigate the inflexion point of degradation, the response of blood vessels, and the pathophysiological process of vascular, as results of such studies will be of great value for the design of next generation of BRS. In this study, abdominal aortas of SD rats were received 3-D printed poly-l-actide vascular scaffolds (PLS) for various durations up to 12 months. The response of PLS implanted aorta went through two distinct processes: (1) the neointima with desirable barrier function was obtained in 1 month, accompanied with slow degradation, inflammation, and intimal hyperplasia; (2) significant degradation occurred from 6 months, accompanied with decreasing inflammation and intimal hyperplasia, while the extracellular matrix recovered to normal vessels which indicate the positive remodeling. These in vivo results indicate that 6 months is a key turning point. This “two-stage degradation and vascular characteristics” is proposed to elucidate the long-term effects of PLS on vascular repair and demonstrated the potential of PLS in promoting endothelium function and positive remodeling, which highlights the benefits of PLS and shed some light in the future researches, such as drug combination coatings design.

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Proposed two-stage degradation of a PLLA BRS to reveal distinct neointimal recovery and vascular responsive processes.

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Revealed novel benefits of BRS, including fine endothelium function, anti-thrombosis, and anti-inflammatory.

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Drug combination coatings should be designed concerning special degradation of BRS and the key turning point, 6 months.

Proteomic Studies of Blood and Vascular Wall in Atherosclerosis

The review is devoted to the analysis of literature data related to the role of proteomic studies in the study of atherosclerotic cardiovascular diseases. Diagnosis of patients with atherosclerotic plaques before clinical manifestations is an arduous task. The review presents the results of research on the new proteomic potential biomarkers of coronary heart disease, coronary atherosclerosis, acute coronary syndrome, myocardial infarction, carotid artery atherosclerosis. Also, the analysis of literature data on proteomic studies of the vascular wall was carried out. To assess the involvement of proteins in the pathological process of atherosclerosis, it is important to investigate the specific relationships between proteins in the arteries, expression and concentration of proteins. The development of proteomic technologies has made it possible to analyse the number of proteins associated with the development of the disease. Analysis of the proteomic profile of the vascular wall in atherosclerosis can help to detect possible diagnostically significant protein structures or potential biomarkers of the disease and develop novel approaches to the diagnosis of atherosclerosis and its complications.

Microtubules as Major Regulators of Endothelial Function: Implication for Lung Injury

Endothelial dysfunction has been attributed as one of the major complications in COVID-19 patients, a global pandemic that has already caused over 4 million deaths worldwide. The dysfunction of endothelial barrier is characterized by an increase in endothelial permeability and inflammatory responses, and has even broader implications in the pathogenesis of acute respiratory syndromes such as ARDS, sepsis and chronic illnesses represented by pulmonary arterial hypertension and interstitial lung disease. The structural integrity of endothelial barrier is maintained by cytoskeleton elements, cell-substrate focal adhesion and adhesive cell junctions. Agonist-mediated changes in endothelial permeability are directly associated with reorganization of actomyosin cytoskeleton leading to cell contraction and opening of intercellular gaps or enhancement of cortical actin cytoskeleton associated with strengthening of endothelial barrier. The role of actin cytoskeleton remodeling in endothelial barrier regulation has taken the central stage, but the impact of microtubules in this process remains less explored and under-appreciated. This review will summarize the current knowledge on the crosstalk between microtubules dynamics and actin cytoskeleton remodeling, describe the signaling mechanisms mediating this crosstalk, discuss epigenetic regulation of microtubules stability and its nexus with endothelial barrier maintenance, and overview a role of microtubules in targeted delivery of signaling molecules regulating endothelial permeability and inflammation.

Morphological Alterations and Stress Protein Variations in Lung Biopsies Obtained from Autopsies of COVID-19 Subjects

Molecular chaperones, many of which are heat shock proteins, play a role in cell stress response and regulate the immune system in various ways, such as in inflammatory/autoimmune reactions. It would be interesting to study the involvement of these molecules in the damage done to COVID-19-infected lungs. In our study, we performed a histological analysis and an immunomorphological evaluation on lung samples from subjects who succumbed to COVID-19 and subjects who died from other causes. We also assessed Hsp60 and Hsp90 distribution in lung samples to determine their location and post-translational modifications. We found histological alterations that could be considered pathognomonic for COVID-19-related lung disease. Hsp60 and Hsp90 immunopositivity was significantly higher in the COVID-19 group compared to the controls, and immunolocalization was in the plasma membrane of the endothelial cells in COVID-19 subjects. The colocalization ratios for Hsp60/3-nitrotyrosine and Hsp60/acetylate-lisine were significantly increased in the COVID-19 group compared to the control group, similar to the colocalization ratio for Hsp90/acetylate-lisine. The histological and immunohistochemical findings led us to hypothesize that Hsp60 and Hsp90 might have a role in the onset of the thromboembolic phenomena that lead to death in a limited number of subjects affected by COVID-19. Further studies on a larger number of samples obtained from autopsies would allow to confirm these data as well as discover new biomarkers useful in the battle against this disease.

Comparison of Surface Functionalization of PLGA Composite to Immobilize Extracellular Vesicles

Endothelialization by materials provides a promising approach for the rapid re-endothelialization of a cardiovascular implantation. Although previous studies have focused on improving endothelialization through the immobilization of bioactive molecules onto the surface of biodegradable implants, comparative studies of effective surface modification have not yet been reported. Here, we conducted a comparative study on the surface modification of poly(lactide-co-glycolide) (PLGA)-based composites to graft mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) using three different materials, fibronectin (FN), polyethylenimine (PEI), and polydopamine (PDA), which have different bond strengths of ligand–receptor interaction, ionic bond, and covalent bond, respectively. Further in vitro analysis exhibited that MSC-EVs released from all modified films sustainably, but the MSC-EVs grafted onto the surface coated with PEI are more effective than other groups in increasing angiogenesis and reducing the inflammatory responses in endothelial cells. Therefore, the overall results demonstrated that PEI is a desirable coating reagent for the immobilization of MSC-EVs on the surface of biodegradable implants.

CRISPR-Based Activation of Endogenous Expression of TPM1 Inhibits Inflammatory Response of Primary Human Coronary Artery Endothelial and Smooth Muscle Cells Induced by Recombinant Human Tumor Necrosis Factor α

Tumor necrosis factor α (TNFα) is one of the most important proinflammatory cytokines, which affects many processes associated with the growth and characteristics of endothelial, smooth muscle, and immune system cells. However, there is no correlation between most in vivo and in vitro studies on its role in endothelial cell proliferation and migration. In this study, we examined the effect of recombinant human (rh) TNFα produced in HEK293 cells on primary human coronary artery endothelial cells (pHCAECs) in the context of F-actin organization and such processes as migration and adhesion. Furthermore, we evaluated the possibility of the inhibition of the endothelial inflammatory response by the CRISPR-based regulation of TPM1 gene expression. We showed that TNFα-induced activation of pHCAECs was related to the reorganization of the actin cytoskeleton into parallel-arranged stress fibers running along the longer axis of pHCAECs. It allowed for the directed and parallel motion of the cells during coordinated migration. This change in F-actin organization promoted strong but discontinuous cell–cell contacts involved in signalization between migrating cells. Moreover, this form of intercellular connections together with locally increased adhesion was related to the formation of migrasomes and further migracytosis. Stabilization of the actin cytoskeleton through the CRISPR-based activation of endogenous expression of TPM1 resulted in the inhibition of the inflammatory response of pHCAECs following treatment with rh TNFα and stabilization of cell–cell junctions through reduced cleavage of vascular endothelial cadherin (VE-cadherin) and maintenance of the stable levels of α- and β-catenins. We also showed that CRISPR-based activation of TPM1 reduced inflammatory activation, proliferation, and migration of primary human coronary artery smooth muscle cells. Therefore, products of the TPM1 gene may be a potential therapeutic target for the treatment of proinflammatory vascular disorders.

miR-181c level predicts response to exercise training in patients with heart failure and preserved ejection fraction: an analysis of the OptimEx-Clin trial

AIMS

In patients with heart failure with preserved ejection fraction (HFpEF), exercise training improves the quality of life and aerobic capacity (peakV·O2). Up to 55% of HF patients, however, show no increase in peakV·O2 despite adequate training. We hypothesized that circulating microRNAs (miRNAs) can distinguish exercise low responders (LR) from exercise high responders (HR) among HFpEF patients.

METHODS AND RESULTS

We selected HFpEF patients from the Optimizing Exercise Training in Prevention and Treatment of Diastolic HF (OptimEx) study which attended ≥70% of training sessions during 3 months (n = 51). Patients were defined as HR with a change in peakV·O2 above median (6.4%), and LR as below median (n = 30 and n = 21, respectively). Clinical, ergospirometric, and echocardiographic characteristics were similar between LR and HR. We performed an miRNA array (n = 377 miRNAs) in 14 age- and sex-matched patients. A total of 10 miRNAs were upregulated in LR, of which 4 correlated with peakV·O2. Validation in the remaining 37 patients indicated that high miR-181c predicted reduced peakV·O2 response (multiple linear regression, β = -2.60, P = 0.011), and LR status (multiple logistic regression, odds ratio = 0.48, P = 0.010), independent of age, sex, body mass index, and resting heart rate. Furthermore, miR-181c decreased in LR after exercise training (P-group = 0.030, P-time = 0.048, P-interaction = 0.037). An in silico pathway analysis identified several downstream targets involved in exercise adaptation.

CONCLUSIONS

Circulating miR-181c is a marker of the response to exercise training in HFpEF patients. High miR-181c levels can aid in identifying LR prior to training, providing the possibility for individualized management.

Thrombin Inhibition Prevents Endothelial Dysfunction and Reverses 20-HETE Overproduction without Affecting Blood Pressure in Angiotensin II-Induced Hypertension in Mice

Angiotensin II (Ang II) induces hypertension and endothelial dysfunction, but the involvement of thrombin in these responses is not clear. Here, we assessed the effects of the inhibition of thrombin activity by dabigatran on Ang II-induced hypertension and endothelial dysfunction in mice with a particular focus on NO- and 20-HETE-dependent pathways. As expected, dabigatran administration significantly delayed thrombin generation (CAT assay) in Ang II-treated hypertensive mice, and interestingly, it prevented endothelial dysfunction development, but it did not affect elevated blood pressure nor excessive aortic wall thickening. Dabigatran’s effects on endothelial function in Ang II-treated mice were evidenced by improved NO-dependent relaxation in the aorta in response to acetylcholine in vivo (MRI measurements) and increased systemic NO bioavailability (NO₂⁻ quantification) with a concomitant increased ex vivo production of endothelium-derived NO (EPR analysis). Dabigatran treatment also contributed to the reduction in the endothelial expression of pro-inflammatory vWF and ICAM-1. Interestingly, the fall in systemic NO bioavailability in Ang II-treated mice was associated with increased 20-HETE concentration in plasma (UPLC-MS/MS analysis), which was normalised by dabigatran treatment. Taking together, the inhibition of thrombin activity in Ang II-induced hypertension in mice improves the NO-dependent function of vascular endothelium and normalises the 20-HETE-depedent pathway without affecting the blood pressure and vascular remodelling.

The Cx43 Carboxyl-Terminal Mimetic Peptide αCT1 Protects Endothelial Barrier Function in a ZO1 Binding-Competent Manner

The Cx43 carboxyl-terminus (CT) mimetic peptide, αCT1, originally designed to bind to Zonula Occludens 1 (ZO1) and thereby inhibit Cx43/ZO1 interaction, was used as a tool to probe the role of Cx43/ZO1 association in regulation of epithelial/endothelial barrier function. Using both in vitro and ex vivo methods of barrier function measurement, including Electric Cell-Substrate Impedance Sensing (ECIS), a TRITC-dextran Transwell permeability assay, and a FITC-dextran cardiovascular leakage protocol involving Langendorff-perfused mouse hearts, αCT1 was found to protect the endothelium from thrombin-induced breakdown in cell-cell contacts. Barrier protection was accompanied by significant remodeling of the F-actin cytoskeleton, characterized by a redistribution of F-actin away from the cytoplasmic and nuclear regions of the cell, towards the endothelial cell periphery, in association with alterations in cellular chiral orientation distribution. In line with observations of increased cortical F-actin, αCT1 upregulated cell-cell border localization of endothelial VE-cadherin, the tight junction protein Zonula Occludens 1 (ZO1), and the Gap Junction Protein (GJ) Connexin43 (Cx43). A ZO1 binding-incompetent variant of αCT1, αCT1-I, indicated that these effects on barrier function and barrier-associated proteins, were likely associated with Cx43 CT sequences retaining ability to interact with ZO1. These results implicate the Cx43 CT and its interaction with ZO1, in the regulation of endothelial barrier function, while revealing the therapeutic potential of αCT1 in the treatment of vascular edema.

Contemporary Lifestyle and Neutrophil Extracellular Traps: An Emerging Link in Atherosclerosis Disease

Neutrophil extracellular traps (NETs) are networks of extracellular genetic material decorated with proteins of nuclear, granular and cytosolic origin that activated neutrophils expel under pathogenic inflammatory conditions. NETs are part of the host's innate immune defense system against invading pathogens. Interestingly, these extracellular structures can also be released in response to sterile inflammatory stimuli (e.g., shear stress, lipidic molecules, pro-thrombotic factors, aggregated platelets, or pro-inflammatory cytokines), as in atherosclerosis disease. Indeed, NETs have been identified in the intimal surface of diseased arteries under cardiovascular disease conditions, where they sustain inflammation via NET-mediated cell-adhesion mechanisms and promote cellular dysfunction and tissue damage via NET-associated cytotoxicity. This review will focus on (1) the active role of neutrophils and NETs as underestimated players of the inflammatory process during atherogenesis and lesion progression; (2) how these extracellular structures communicate with the main cell types present in the atherosclerotic lesion in the arterial wall; and (3) how these neutrophil effector functions interplay with lifestyle-derived risk factors such as an unbalanced diet, physical inactivity, smoking or lack of sleep quality, which represent major elements in the development of cardiovascular disease.

Detrimental or beneficial: Role of endothelial ENaC in vascular function

In the past, it was believed that the expression of the epithelial sodium channel (ENaC) was restricted to epithelial tissues, such as the distal nephron, airway, sweat glands, and colon, where it is critical for sodium homeostasis. Over the past two decades, this paradigm has shifted due to the finding that ENaC is also expressed in various nonepithelial tissues, notably in vascular endothelial cells. In this review, the recent findings of the expression, regulation, and function of the endothelial ENaC (EnNaC) are discussed. The expression of EnNaC subunits is reported in a variety of endothelial cell lines and vasculatures, but this is controversial across different species and vessels and is not a universal finding in all vascular beds. The expression density of EnNaC is very faint compared to ENaC in the epithelium. To date, little is known about the regulatory mechanism of EnNaC. Through it can be regulated by aldosterone, the detailed downstream signaling remains elusive. EnNaC responds to increased extracellular sodium with the feedforward activation mechanism, which is quite different from the Na⁺ self-inhibition mechanism of ENaC. Functionally, EnNaC was shown to be a determinant of cellular mechanics and vascular tone as it can sense shear stress, and its activation or insertion into plasma membrane causes endothelial stiffness and reduced nitric oxide production. However, in some blood vessels, EnNaC is essential for maintaining the integrity of endothelial barrier function. In this context, we discuss the possible reasons for the distinct role of EnNaC in vasculatures.

Glucose Derivative Induced Vasculopathy in Children on Chronic Peritoneal Dialysis

[Figure: see text].

Systematic Bioinformatic Analyses of Nutrigenomic Modifications by Polyphenols Associated with Cardiometabolic Health in Humans-Evidence from Targeted Nutrigenomic Studies

Cardiometabolic disorders are among the leading causes of mortality in the human population. Dietary polyphenols exert beneficial effects on cardiometabolic health in humans. Molecular mechanisms, however, are not completely understood. Aiming to conduct in-depth integrative bioinformatic analyses to elucidate molecular mechanisms underlying the protective effects of polyphenols on cardiometabolic health, we first conducted a systematic literature search to identify human intervention studies with polyphenols that demonstrate improvement of cardiometabolic risk factors in parallel with significant nutrigenomic effects. Applying the predefined inclusion criteria, we identified 58 differentially expressed genes at mRNA level and 5 miRNAs, analyzed in peripheral blood cells with RT-PCR methods. Subsequent integrative bioinformatic analyses demonstrated that polyphenols modulate genes that are mainly involved in the processes such as inflammation, lipid metabolism, and endothelial function. We also identified 37 transcription factors that are involved in the regulation of polyphenol modulated genes, including RELA/NFKB1, STAT1, JUN, or SIRT1. Integrative bioinformatic analysis of mRNA and miRNA-target pathways demonstrated several common enriched pathways that include MAPK signaling pathway, TNF signaling pathway, PI3K-Akt signaling pathway, focal adhesion, or PPAR signaling pathway. These bioinformatic analyses represent a valuable source of information for the identification of molecular mechanisms underlying the beneficial health effects of polyphenols and potential target genes for future nutrigenetic studies.

HOXA9 inhibitors promote microcirculation of coronary arteries in rats via downregulating E-selectin/VCAM-1

Atherosclerosis (AS) is a chronic pathophysiological process that causes high mortality and morbidity. It has previously been reported that homeobox A9 (HOXA9) may participate in regulation of the cardiovascular system and the pathology of AS by upregulating E-selectin and vascular cell adhesion molecule-1 (VCAM-1). Thus, inhibiting HOXA9 could promote microcirculation of coronary arteries and could act as a potential therapy for AS treatment. Sprague-Dawley rats were randomly divided into four groups, as follows: i) AS; ii) AS + HOXA9 inhibitor; iii) AS + small interfering RNA-HOXA9 and iv) normal control. ELISA was used to measure the levels of TNF-α, IL-1β, IL-12, C-C motif chemokine ligand 25 (CCL25), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and very-low-density lipoprotein (VLDL). Flow cytometry was employed to detect the content of M1 macrophages. Hematoxylin & eosin (H&E) staining was performed to observe the morphology of the coronary arteries. Oil red O staining was conducted for the evaluation of lipid accumulation. Immunohistochemistry was used to visualize the protein expression levels of HOXA9 in the coronary arteries. Western blotting was utilized to determine the protein expression levels of HOXA9, platelet factor-4 (PF4), E-selectin and VCAM-1. HOXA9 inhibitors were found to downregulate the levels of TNF-α, IL-1β, IL-12, CCL25, LDL and VLDL, and upregulate HDL levels in the blood of AS rats. The content of M1 macrophages was also decreased following injection of HOXA9 inhibitors in the AS group. H&E and oil red O staining analysis indicated that HOXA9 inhibitors attenuated vascular symptoms and lipid formation in AS rats. Furthermore, western blotting suggested that inhibition of HOXA9 reduced the expression levels of PF4, E-selectin and VCAM-1, while overexpression of PF4 resulted in the opposite effects. The present study revealed that inhibiting HOXA9 alleviated the symptoms of AS via downregulation of the PF4 and E-selectin/VCAM-1 pathway to promote microcirculation in the coronary arteries of AS rats. These findings indicated that HOXA9 inhibitors may have the potential to succeed in the treatment of AS.

A high-throughput microfluidic bilayer co-culture platform to study endothelial-pericyte interactions

Microphysiological organ-on-chip models offer the potential to improve the prediction of drug safety and efficacy through recapitulation of human physiological responses. The importance of including multiple cell types within tissue models has been well documented. However, the study of cell interactions in vitro can be limited by complexity of the tissue model and throughput of current culture systems. Here, we describe the development of a co-culture microvascular model and relevant assays in a high-throughput thermoplastic organ-on-chip platform, PREDICT96. The system consists of 96 arrayed bilayer microfluidic devices containing retinal microvascular endothelial cells and pericytes cultured on opposing sides of a microporous membrane. Compatibility of the PREDICT96 platform with a variety of quantifiable and scalable assays, including macromolecular permeability, image-based screening, Luminex, and qPCR, is demonstrated. In addition, the bilayer design of the devices allows for channel- or cell type-specific readouts, such as cytokine profiles and gene expression. The microvascular model was responsive to perturbations including barrier disruption, inflammatory stimulation, and fluid shear stress, and our results corroborated the improved robustness of co-culture over endothelial mono-cultures. We anticipate the PREDICT96 platform and adapted assays will be suitable for other complex tissues, including applications to disease models and drug discovery.

Promotion of vascular integrity in sepsis through modulation of bioactive adrenomedullin and dipeptidyl peptidase 3

Sepsis represents one of the major medical challenges of the 21st century. Despite substantial improvements in the knowledge on pathophysiological mechanisms, this has so far not translated into novel adjuvant treatment strategies for sepsis. In sepsis, both vascular tone and vascular integrity are compromised, and contribute to the development of shock, which is strongly related to the development of organ dysfunction and mortality. In this review, we focus on dipeptidyl peptidase 3 (DPP3) and adrenomedullin (ADM), two molecules that act on the vasculature and are involved in the pathophysiology of sepsis and septic shock. DPP3 is an ubiquitous cytosolic enzyme involved in the degradation of several important signalling molecules essential for regulation of vascular tone, including angiotensin II. ADM is a key hormone involved in the regulation of vascular tone and endothelial barrier function. Previous studies have shown that circulating concentrations of both DPP3 and ADM are independently associated with the development of organ failure and adverse outcome in sepsis. We now discuss new evidence illustrating that these molecules indeed represent two distinct pathways involved in the development of septic shock. Recently, both ADM-enhancing therapies aimed at improving endothelial barrier function and vascular tone and DPP3-blocking therapies aimed at restoring systemic angiotensin responses have been shown to improve outcome in various preclinical sepsis models. Given the current lack of effective adjuvant therapies in sepsis, additional research on the therapeutic application of these peptides in humans is highly warranted.

Oxidative stress inducers potentiate 2,3,7,8-tetrachlorodibenzo-p-dioxin-mediated pre-cardiac edema in larval zebrafish

We reported the involvement of oxidative stress and prostaglandins including thromboxane and prostacyclin in pre-cardiac edema (early edema) caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). While the involvement of oxidative stress in TCDD-induced toxicity has been frequently reported, the mechanism of its action is still unclear. In the present study, oxidative stress inducers including paraquat, hydrogen peroxide (H₂O₂) and rotenone augmented early edema (edema) induced by a low concentration of TCDD (0.1 ppb) at 55 hr post fertilization (hpf), while each of them alone did not cause edema. Edema caused by TCDD plus oxidative stress inducers was almost abolished by antioxidants, an antagonist for thromboxane receptor (ICI-192,605) and an agonist for prostacyclin receptor (beraprost), suggesting that the site of action of these inducers was in the regular signaling pathway after activation of aryl hydrocarbon receptor type 2 (AHR2) by TCDD. Oxidative stress inducers also enhanced edema caused by an agonist for the thromboxane receptor (U46619), and the enhancement was also inhibited by antioxidants. Sulforaphane and auranofin, activators of Nrf2 that is a master regulator of anti-oxidative response, did not affect U46619-evoked edema but almost abolished TCDD-induced edema and potentiation by paraquat in both TCDD- and U46619-induced edema. Taken together, the results suggest that oxidative stress augments pre-cardiac edema caused by TCDD via activation of thromboxane receptor-mediated signaling in developing zebrafish. As paraquat and other oxidative stress inducers used also are environmental pollutants, interaction between dioxin-like compounds and exogenous source of oxidative stress should also be considered.

Circulating biomarkers to assess cardiovascular function in critically ill

PURPOSE OF REVIEW

Circulatory shock is one of the most common reasons for ICU admission. Mortality rates in excess of 40% necessitate the rapid identification of high-risk patients, as well as the early assessment of effects of initiated treatments. There is an unmet medical need for circulating biomarkers that may improve patient stratification, predict responses to treatment interventions and may even be a target for novel therapies, enabling a better biological rationale to personalize therapy.

RECENT FINDINGS

Apart from established biomarkers such as lactate, ScvO2 or NT-pro-BNP, novel biomarkers, including adrenomedullin, angiopoietins, angiotensin I/II ratios, renin and DPP3 show promise, as they are all associated with well defined, therapeutically addressable molecular pathways that are dysregulated during circulatory shock. Although some of the therapies related to these biomarkers are still in preclinical stages of development, they may represent personalized treatment opportunities for patients in circulatory shock.

SUMMARY

From a molecular perspective, shock represents a highly heterologous syndrome, in which multiple unique pathways are dysregulated. Assessment of the status of these pathways with circulating biomarkers may provide a unique opportunity to detect specific phenotypes and implement personalized medicine in the treatment of circulatory shock.

Uremic Toxins: An Alarming Danger Concerning the Cardiovascular System

The kidneys and heart share functions with the common goal of maintaining homeostasis. When kidney injury occurs, many compounds, the so-called "uremic retention solutes" or "uremic toxins," accumulate in the circulation targeting other tissues. The accumulation of uremic toxins such as p-cresyl sulfate, indoxyl sulfate and inorganic phosphate leads to a loss of a substantial number of body functions. Although the concept of uremic toxins is dated to the 1960s, the molecular mechanisms capable of leading to renal and cardiovascular injuries are not yet known. Besides, the greatest toxic effects appear to be induced by compounds that are difficult to remove by dialysis. Considering the close relationship between renal and cardiovascular functions, an understanding of the mechanisms involved in the production, clearance and overall impact of uremic toxins is extremely relevant for the understanding of pathologies of the cardiovascular system. Thus, the present study has as main focus to present an extensive review on the impact of uremic toxins in the cardiovascular system, bringing the state of the art on the subject as well as clinical implications related to patient's therapy affected by chronic kidney disease, which represents high mortality of patients with cardiac comorbidities.

Role of Microparticles in Cardiovascular Disease: Implications for Endothelial Dysfunction, Thrombosis, and Inflammation

[Figure: see text].

C-C motif ligand 8 promotes atherosclerosis via NADPH oxidase 2/reactive oxygen species-induced endothelial permeability increase

Chemokines have been reported to play important roles in atherosclerotic development. Recently, we found C-C motif ligand 8 (CCL8), a rarely studied chemokine in atherosclerosis, was highly expressed in the endothelium of advanced human carotid plaques. We hypothesized whether CCL8 promotes atherosclerosis through endothelial dysfunction. Apolipoprotein E-deficient mice under the Western diet were used to construct atherosclerosis models. Adeno-associated viruses (AAV) with CCL8 and the CCL8-antibody were injected into mice respectively to conduct CCL8 overexpression and suppression. The results showed that atherosclerotic lesions were significantly increased in the AAV-CCL8 group, while, lesions in the aortic sinus were reduced in the CCL8-antibody group. With CCL8 treatment (200 ng/ml, 24 h) in vitro, the permeability of human aortic endothelial cells (HAECs) increased and the expression of junctional proteins Zonula occluden-1, and Vascular endothelial cadherin were decreased. This effect was dependent on reactive oxygen species (ROS) generation, which could be blocked by l-Ascorbic acid and Apocynin. Results showed that NADPH oxidase 2 (NOX2) expression also increased with CCL8 stimulation and the ROS, and permeability increase of HAECs could be inhibited when NOX2 interfered with the specific siRNA. Additionally, we further found ERK1/2, PI3K-AKT, and NF-κB pathways were involved in the activation of CCL8. Our results indicated that CCL8 might also play important roles in atherosclerosis and this effect, at least in part, was caused by NOX2/ROS-induced endothelial permeability increase. This study might contribute to a deeper understanding of the connection between chemokines and atherosclerosis.

Induction of the Coxsackievirus and Adenovirus Receptor in Macrophages During the Formation of Atherosclerotic Plaques

Multiple viruses are implicated in atherosclerosis, but the mechanisms by which they infect cells and contribute to plaque formation in arterial walls are not well understood. Based on reports showing the presence of enterovirus in atherosclerotic plaques we hypothesized that the coxsackievirus and adenovirus receptor (CXADR/CAR), although absent in normal arteries, could be induced during plaque formation. Large-scale microarray and mass spectrometric analyses revealed significant up-regulation of CXADR messenger RNA and protein levels in plaque-invested carotid arteries compared with control arteries. Macrophages were identified as a previously unknown cellular source of CXADR in human plaques and plaques from Ldr-/-Apob100/100 mice. CXADR was specifically associated with M1-polarized macrophages and foam cells and was experimentally induced during macrophage differentiation. Furthermore, it was significantly correlated with receptors for other viruses linked to atherosclerosis. The results show that CXADR is induced in macrophages during plaque formation, suggesting a mechanism by which enterovirus infect cells in atherosclerotic plaques.

Neutrophil transendothelial migration hotspots - mechanisms and implications

During inflammation, leukocytes circulating in the blood stream exit the vasculature in a process called leukocyte transendothelial migration (TEM). The current paradigm of this process comprises several well-established steps, including rolling, adhesion, crawling, diapedesis and sub-endothelial crawling. Nowadays, the role of the endothelium in transmigration is increasingly appreciated. It has been established that leukocyte exit sites on the endothelium and in the pericyte layer are in fact not random but instead may be specifically recognized by migrating leukocytes. Here, we review the concept of transmigration hotspots, specific sites in the endothelial and pericyte layer where most transmigration events take place. Chemokine cues, adhesion molecules and membrane protrusions as well as physical factors, such as endothelial junction stability, substrate stiffness, the presence of pericytes and basement membrane composition, may all contribute to local hotspot formation to facilitate leukocytes exiting the vasculature. In this Review, we discuss the biological relevance of such hotspots and put forward multiple mechanisms and factors that determine a functional TEM hotspot.

The Potential Role of Creatine in Vascular Health

Creatine is an organic compound, consumed exogenously in the diet and synthesized endogenously via an intricate inter-organ process. Functioning in conjunction with creatine kinase, creatine has long been known for its pivotal role in cellular energy provision and energy shuttling. In addition to the abundance of evidence supporting the ergogenic benefits of creatine supplementation, recent evidence suggests a far broader application for creatine within various myopathies, neurodegenerative diseases, and other pathologies. Furthermore, creatine has been found to exhibit non-energy related properties, contributing as a possible direct and in-direct antioxidant and eliciting anti-inflammatory effects. In spite of the new clinical success of supplemental creatine, there is little scientific insight into the potential effects of creatine on cardiovascular disease (CVD), the leading cause of mortality. Taking into consideration the non-energy related actions of creatine, highlighted in this review, it can be speculated that creatine supplementation may serve as an adjuvant therapy for the management of vascular health in at-risk populations. This review, therefore, not only aims to summarize the current literature surrounding creatine and vascular health, but to also shed light onto the potential mechanisms in which creatine may be able to serve as a beneficial supplement capable of imparting vascular-protective properties and promoting vascular health.

Mechanisms of vascular damage by systemic dissemination of the oral pathogen Porphyromonas gingivalis

Several studies have shown a clear association between periodontal disease and increased risk of cardiovascular disease. Porphyromonas gingivalis (Pg), a key oral pathogen, and its cell surface-expressed gingipains, induce oedema in a zebrafish larvae infection model although the mechanism of these vascular effects is unknown. Here, we aimed to determine whether Pg-induced vascular damage is mediated by gingipains. In vitro, human endothelial cells from different vascular beds were invaded by wild-type (W83) but not gingipain-deficient (ΔK/R-ab) Pg. W83 infection resulted in increased endothelial permeability as well as decreased cell surface abundance of endothelial adhesion molecules PECAM-1 and VE-cadherin compared to infection with ΔK/R-ab. In agreement, when transgenic zebrafish larvae expressing fluorescently labelled PECAM-1 or VE-cadherin were systemically infected with W83 or ΔK/R-ab, a significant reduction in adhesion molecule fluorescence was observed specifically in endothelium proximal to W83 bacteria through a gingipain-dependent mechanism. Furthermore, this was associated with increased vascular permeability in vivo when assessed by dextran leakage microangiography. These data are the first to show that Pg directly mediates vascular damage in vivo by degrading PECAM-1 and VE-cadherin. Our data provide a molecular mechanism by which Pg might contribute to cardiovascular disease.

S-1-propenylcysteine improves TNF-α-induced vascular endothelial barrier dysfunction by suppressing the GEF-H1/RhoA/Rac pathway

Background

Vascular endothelial barrier function is maintained by cell-to-cell junctional proteins and contributes to vascular homeostasis. Various risk factors such as inflammation disrupt barrier function through down-regulation of these proteins and promote vascular diseases such as atherosclerosis. Previous studies have demonstrated that aged garlic extract (AGE) and its sulfur-containing constituents exert the protective effects against several vascular diseases such as atherosclerosis. In this study, we examined whether AGE and its sulfur-containing constituents improve the endothelial barrier dysfunction elicited by a pro-inflammatory cytokine, Tumor-necrosis factor-α (TNF-α), and explored their mode of action on TNF-α signaling pathway.

Methods

Human umbilical vein endothelial cells (HUVECs) were treated with test substances in the presence of TNF-α for various time periods. The endothelial permeability was measured by using a transwell permeability assay. The localization of cell-to-cell junctional proteins and actin cytoskeletons were visualized by immunostaining. RhoA and Rac activities were assessed by using GTP-binding protein pulldown assay. Gene and protein expression levels of signaling molecules were analyzed by real-time PCR and western blotting, respectively.

Results

We found that AGE and its major sulfur-containing constituent, S-1-propenylcysteine (S1PC), reduced hyperpermeability elicited by TNF-α in HUVECs. In addition, S1PC inhibited TNF-α-induced production of myosin light chain (MLC) kinase and inactivation of MLC phosphatase through the suppression of the Rac and RhoA signaling pathways, respectively, which resulted in the dephosphorylation of MLC2, a key factor of actin remodeling. Moreover, S1PC inhibited the phosphorylation and activation of guanine nucleotide exchange factor-H1 (GEF-H1), a common upstream key molecule and activator of Rac and RhoA. These effects of S1PC were accompanied by its ability to prevent the disruption of junctional proteins on the cell–cell contact regions and the increase of actin stress fibers induced by TNF-α.

Conclusions

The present study suggested that AGE and its major constituent, S1PC, improve endothelial barrier disruption through the protection of junctional proteins on plasma membrane.

Uremic Toxins, Oxidative Stress, Atherosclerosis in Chronic Kidney Disease, and Kidney Transplantation

Patients with chronic kidney disease (CKD) are at a high risk for cardiovascular disease (CVD), and approximately half of all deaths among patients with CKD are a direct result of CVD. The premature cardiovascular disease extends from mild to moderate CKD stages, and the severity of CVD and the risk of death increase with a decline in kidney function. Successful kidney transplantation significantly decreases the risk of death relative to long-term dialysis treatment; nevertheless, the prevalence of CVD remains high and is responsible for approximately 20-35% of mortality in renal transplant recipients. The prevalence of traditional and nontraditional risk factors for CVD is higher in patients with CKD and transplant recipients compared with the general population; however, it can only partly explain the highly increased cardiovascular burden in CKD patients. Nontraditional risk factors, unique to CKD patients, include proteinuria, disturbed calcium, and phosphate metabolism, anemia, fluid overload, and accumulation of uremic toxins. This accumulation of uremic toxins is associated with systemic alterations including inflammation and oxidative stress which are considered crucial in CKD progression and CKD-related CVD. Kidney transplantation can mitigate the impact of some of these nontraditional factors, but they typically persist to some degree following transplantation. Taking into consideration the scarcity of data on uremic waste products, oxidative stress, and their relation to atherosclerosis in renal transplantation, in the review, we discussed the impact of uremic toxins on vascular dysfunction in CKD patients and kidney transplant recipients. Special attention was paid to the role of native and transplanted kidney function.

5-HT2A Receptor and 5-HT Degradation Play a Crucial Role in Atherosclerosis by Modulating Macrophage Foam Cell Formation, Vascular Endothelial Cell Inflammation, and Hepatic Steatosis

Aim: Previously, we found that diabetes-related liver dysfunction is due to activation of the 5-HT _2A receptor (5-HT _2A R) and increased synthesis and degradation of 5-HT. Here, we investigated the role of 5-HT in the development of atherosclerosis.

Methods: The study was conducted using high-fat diet-fed male ApoE ^−/− mice, THP-1 cell-derived macrophages, and HUVECs. Protein expression and biochemical indexes were determined by Western blotting and quantitative analysis kit, respectively. The following staining methods were used: oil red O staining (showing atherosclerotic plaques and intracellular lipid droplets), immunohistochemistry (showing the expression of 5-HT _2A R, 5-HT synthase, and CD68 in the aortic wall), and fluorescent probe staining (showing intracellular ROS).

Results: In addition to improving hepatic steatosis, insulin resistance, and dyslipidemia, co-treatment with a 5-HT synthesis inhibitor and a 5-HT _2A R antagonist significantly suppressed the formation of atherosclerotic plaques and macrophage infiltration in the aorta of ApoE ^−/− mice in a synergistic manner. Macrophages and HUVECs exposed to oxLDL or palmitic acid in vitro showed that activated 5-HT _2A R regulated TG synthesis and oxLDL uptake by activating PKCε, resulting in formation of lipid droplets and even foam cells; ROS production was due to the increase of both intracellular 5-HT synthesis and mitochondrial MAO-A-catalyzed 5-HT degradation, which leads to the activation of NF-κB and the release of the inflammatory cytokines TNF-α and IL-1β from macrophages and HUVECs as well as MCP-1 release from HUVECs.

Conclusion: Similar to hepatic steatosis, the pathogenesis of lipid-induced atherosclerosis is associated with activation of intracellular 5-HT _2A R, 5-HT synthesis, and 5-HT degradation.

Suppressive Effects of the Gynura bicolor Ether Extract on Endothelial Permeability and Leukocyte Transmigration in Human Endothelial Cells Induced by TNF-α

Gynura bicolor (Roxb. and Willd.) DC (G. bicolor) is generally used as a dietary vegetable and traditional herb in Taiwan and the Far East. G. bicolor exerts antioxidant and anti-inflammatory effects and regulates blood lipids and cholesterol. However, the effects of G. bicolor on endothelial transmigration and atherosclerosis are not clear. The present study investigated the effects of G. bicolor on endothelial permeability and transmigration in human endothelial cells. We prepared G. bicolor ether extract (GBEE) for use as the experimental material. Under TNF-α stimulation, HL-60 cell adherence to EA.hy926 cells, the shape of EA.hy926 cells, and the expression of adhesion molecules and transmigration-related regulatory molecules were analysed after pretreatment with GBEE for 24 h. GBEE inhibited leukocyte adhesion to endothelial cells, reduced intercellular adhesion molecule-1 (ICAM-1) and platelet endothelial cell adhesion molecule-1 (PECAM-1) expressions, and decreased endothelial monolayer permeability. GBEE also reduced paracellular transmigration by reducing the levels of reactive oxygen species (ROS), Src phosphorylation, and vascular endothelial-cadherin (VE-cadherin) phosphorylation. GBEE reduced transcellular migration via inhibition of Ras homolog family member A (RhoA) and Rho-associated protein kinase (ROCK) expression and phosphorylation of the ezrin-radixin-moesin (ERM) protein. Incubation of EA.hy926 cells with GBEE for 8 h and stimulation with TNF-α for 3 h reduced the phosphorylation of the inhibitor of kappa B (IĸB) and DNA-binding activity of nuclear factor-ĸB (NF-ĸB). These results suggest that GBEE has a protective effect against endothelial dysfunction via suppression of leukocyte-endothelium adhesion and transmigration.

Oxidized Phospholipids in Control of Endothelial Barrier Function: Mechanisms and Implication in Lung Injury

Earlier studies investigating the pathogenesis of chronic vascular inflammation associated with atherosclerosis described pro-inflammatory and vascular barrier disruptive effects of lipid oxidation products accumulated in the sites of vascular lesion and atherosclerotic plaque. However, accumulating evidence including studies from our group suggests potent barrier protective and anti-inflammatory properties of certain oxidized phospholipids (OxPLs) in the lung vascular endothelium. Among these OxPLs, oxidized 1-palmitoyl-2-arachdonyl-sn-glycero-3-phosphocholine (OxPAPC) causes sustained enhancement of lung endothelial cell (EC) basal barrier properties and protects against vascular permeability induced by a wide variety of agonists ranging from bacterial pathogens and their cell wall components, endotoxins, thrombin, mechanical insults, and inflammatory cytokines. On the other hand, truncated OxPLs cause acute endothelial barrier disruption and potentiate inflammation. It appears that multiple signaling mechanisms triggering cytoskeletal remodeling are involved in OxPLs-mediated regulation of EC barrier. The promising vascular barrier protective and anti-inflammatory properties exhibited by OxPAPC and its particular components that have been established in the cellular and animal models of sepsis and acute lung injury has prompted consideration of OxPAPC as a prototype therapeutic molecule. In this review, we will summarize signaling and cytoskeletal mechanisms involved in OxPLs-mediated damage, rescue, and restoration of endothelial barrier in various pathophysiological settings and discuss a future potential of OxPAPC in treating lung disorders associated with endothelial barrier dysfunction.

Platelet function in cats with hyperthyroidism

OBJECTIVES

Cats with hyperthyroidism have been reported to develop thromboembolism, with and without echocardiographic abnormalities consistent with hyperthyroidism. The objective of this study was to compare platelet function in cats with hyperthyroidism with euthyroid age-matched cats. We hypothesized that cats with hyperthyroidism have shortened collagen and adenosine diphosphate (C-ADP) closure times as measured with the platelet function analyzer (PFA-100) in comparison with healthy, age-matched controls.

METHODS

Sixteen hyperthyroid and nine euthyroid healthy cats >7 years of age were recruited from the hospital population. Platelet function, measured using the C-ADP closure times by the PFA-100, and platelet count were measured in healthy euthyroid cats and cats with hyperthyroidism.

RESULTS

Mean ± SD closure times were not significantly different between control (66.3 ± 9.6 s) and hyperthyroid cats (65.9 ± 11.5 s; P = 0.75). The mean ± SD closure times of hyperthyroid cats that either were untreated or received methimazole for ⩽3 weeks (n = 6; mean 68.5 ± 15.4 s) was not different than that of cats treated for >3 weeks (n = 10; mean 64.3 ± 8.9 s; P = 0.57). The mean automated platelet count was higher in the hyperthyroid group than in the control group (P = 0.023).

CONCLUSIONS AND RELEVANCE

Platelet function, as measured by closure time under high shear conditions using C-ADP as an agonist, was not affected by hyperthyroidism in this group of cats. Further research is needed to determine if a hypercoagulable state exists in hyperthyroid cats and the potential roles platelets and von Willebrand factor may have.

Porphyromonas gingivalis Outer Membrane Vesicles Increase Vascular Permeability

Periodontitis is increasingly associated with increased risk of cardiovascular and other systemic diseases. The Gram-negative anaerobe, Porphyromonas gingivalis, is a key periodontal pathogen, and several lines of evidence link the presence of this bacterium in the circulation with vascular disease. The outer membrane vesicles (OMVs) produced by P. gingivalis have been shown to play a role in periodontitis, although, to date, little is known about their interaction with the vasculature; therefore, this study assessed the effects of P. gingivalis OMVs on the endothelium. OMVs were isolated from wild-type strain W83 and the gingipain-deficient strain ΔK/R-ab. Immunoblotting along with cryo-EM showed gingipain expression in W83 but not ΔK/R-ab-derived OMVs, where gingipains were localized to the cell wall surface. Confluent endothelial cell monolayers infected with either W83 or W83-derived OMV displayed significantly increased dextran permeability over those infected with ΔK/R-ab or its OMV. Moreover, W83-derived OMVs induced significantly more vascular disease in a zebrafish larvae systemic infection model over 72 h compared to those injected with gingipain-deficient OMVs or controls. In line with these data, human microvascular endothelial cells (HMEC-1) displayed an OMV-associated, gingipain-dependent decrease in cell surface levels of the intercellular adhesion molecule PECAM-1 (CD31) when examined by flow cytometry. These data show, for the first time, that OMVs from P. gingivalis mediate increased vascular permeability, leading to a diseased phenotype both in vitro and in vivo. Moreover, these data strongly implicate gingipains present on the OMV surface in mediating these vascular events, most likely via a mechanism that involves proteolytic cleavage of endothelial cell-cell adhesins such as PECAM-1. These data provide important evidence for the role of bacterial-derived OMVs in mediating systemic disease.

Platelet Microparticle Controversial Role in Cancer

Platelet-derived microparticles (PMPs) are a group of micrometer-scale extracellular vesicles released by platelets upon activation that are responsible for the majority of microvesicles found in plasma. PMPs’ physiological properties and functions have long been investigated by researchers. In this regard, a noticeable area of studies has been devoted to evaluating the potential roles and effects of PMPs on cancer progression. Clinical and experimental evidence conflictingly implicates supportive and suppressive functions for PMPs regarding cancer. Many of these functions could be deemed as a cornerstone for future considerations of PMPs usage in cancer targeted therapy. This review discusses what is currently known about PMPs and provides insights for new and possible research directions for further grasping the intricate interplay between PMPs and cancer.

Impact of Acute and Chronic Stress on Thrombosis in Healthy Individuals and Cardiovascular Disease Patients

Psychological stress induces different alterations in the organism in order to maintain homeostasis, including changes in hematopoiesis and hemostasis. In particular, stress-induced hyper activation of the autonomic nervous system and hypothalamic–pituitary–adrenal axis can trigger cellular and molecular alterations in platelets, coagulation factors, endothelial function, redox balance, and sterile inflammatory response. For this reason, mental stress is reported to enhance the risk of cardiovascular disease (CVD). However, contrasting results are often found in the literature considering differences in the response to acute or chronic stress and the health condition of the population analyzed. Since thrombosis is the most common underlying pathology of CVDs, the comprehension of the mechanisms at the basis of the association between stress and this pathology is highly valuable. The aim of this work is to give a comprehensive review of the studies focused on the role of acute and chronic stress in both healthy individuals and CVD patients, focusing on the cellular and molecular mechanisms underlying the relationship between stress and thrombosis.

Identification of "antigen-specific" neutrophils in atherosclerosis patients that compromise vascular endothelial barrier function

The vascular endothelial barrier dysfunction is associated with the pathogenesis of many cardiovascular diseases, such as atherosclerosis (AS). This study aims to identify specific antigen (Ag, in short)-specific polymorphonuclear neutrophils (PMN) in AS patients and to investigate the role of "Ag-specific" PMN activation in causing vascular endothelial barrier dysfunction. In this study, PMNs were isolated from blood samples collected from patients with AS and analyzed with immunological approaches. Human umbilical vein endothelial cells (HUVEC) monolayers were used as a vascular endothelial barrier model. The results showed that "Ag-specific" PMNs were identified in the blood of 50 AS patients. This subset of PMN was featured as the FcγRI and specific IgG (sIgG) complexes on the cell surface; exposure to specific Ags triggered the "Ag-specific" PMNs to release proinflammatory cytokines. PMN-derived cytokine levels in the serum were positively correlated with the serum levels of sIgG in AS patients. Exposure of naive PMNs to sIgG formed FcγRI and sIgG complexes on the surface; this conferred PMNs the property to be recognized and activated by specific Ag. Stimulation of "Ag-specific" PMN activated the mitogen-activated protein kinase and the activities of nuclear factor activated T cells and promoted the gene transcription of tumor necrosis factor-α. Coculture of "Ag-specific" PMNs and HUVEC monolayers in the presence of specific Ag resulted in the HUVEC monolayer barrier dysfunction. In conclusion, "Ag-specific" PMNs were identified in AS patients. Activation of the PMNs compromised vascular endothelial barrier function. Therefore, to regulate the "Ag-specific" PMN's activities may have translational potential in the treatment of AS.

Mechanisms of endothelial stiffening in dyslipidemia and aging: Oxidized lipids and shear stress

Vascular stiffening of the arterial walls is well-known as a key factor in aging and the development of cardiovascular disease; however, the role of endothelial stiffness in vascular dysfunction is still an emerging topic. In this review, the authors discuss the impact of dyslipidemia, oxidized lipids, substrate stiffness, age and pro-atherogenic disturbed flow have on endothelial stiffness. Furthermore, we investigate several mechanistic pathways that are key contributors in endothelial stiffness and discuss their physiological effects in the onset of atherogenesis in the disturbed flow regions of the aortic vasculature. The findings in this chapter describe a novel paradigm of synergistic interaction of plasma dyslipidemia/oxidized lipids and pro-atherogenic disturbed shear stress, as well as aging has on endothelial stiffness and vascular dysfunction.

The Evolving Applications of Creatine Supplementation: Could Creatine Improve Vascular Health?

Creatine is a naturally occurring compound, functioning in conjunction with creatine kinase to play a quintessential role in both cellular energy provision and intracellular energy shuttling. An extensive body of literature solidifies the plethora of ergogenic benefits gained following dietary creatine supplementation; however, recent findings have further indicated a potential therapeutic role for creatine in several pathologies such as myopathies, neurodegenerative disorders, metabolic disturbances, chronic kidney disease and inflammatory diseases. Furthermore, creatine has been found to exhibit non-energy-related properties, such as serving as a potential antioxidant and anti-inflammatory. Despite the therapeutic success of creatine supplementation in varying clinical populations, there is scarce information regarding the potential application of creatine for combatting the current leading cause of mortality, cardiovascular disease (CVD). Taking into consideration the broad ergogenic and non-energy-related actions of creatine, we hypothesize that creatine supplementation may be a potential therapeutic strategy for improving vascular health in at-risk populations such as older adults or those with CVD. With an extensive literature search, we have found only four clinical studies that have investigated the direct effect of creatine on vascular health and function. In this review, we aim to give a short background on the pleiotropic applications of creatine, and to then summarize the current literature surrounding creatine and vascular health. Furthermore, we discuss the varying mechanisms by which creatine could benefit vascular health and function, such as the impact of creatine supplementation upon inflammation and oxidative stress.

The polarity protein Scrib limits atherosclerosis development in mice

AIMS

The protein Scrib (Scribble 1) is known to control apico-basal polarity in epithelial cells. The role of polarity proteins in the vascular system remains poorly characterized; however, we previously reported that Scrib maintains the endothelial phenotype and directed migration. On this basis, we hypothesized that Scrib has anti-atherosclerotic functions.

METHODS AND RESULTS

Tamoxifen-induced Scrib-knockout mice were crossed with ApoE-/- knockout mice and spontaneous atherosclerosis under high-fat diet (HFD), as well as accelerated atherosclerosis in response to partial carotid artery ligation and HFD, was induced. Deletion of Scrib resulted in increased atherosclerosis development in both models. Mechanistically, flow- as well as acetylcholine-induced endothelium-dependent relaxation and AKT phosphorylation was reduced by deletion of Scrib, whereas vascular permeability and leucocyte extravasation were increased after Scrib knockout. Scrib immune pull down in primary carotid endothelial cells and mass spectrometry identified Arhgef7 (Rho Guanine Nucleotide Exchange Factor 7, βPix) as interaction partner. Scrib or Arhgef7 down-regulation by siRNA reduced the endothelial barrier function in human umbilical vein endothelial cells. Gene expression analysis from murine samples and from human biobank material of carotid endarterectomies indicated that loss of Scrib resulted in endothelial dedifferentiation with a decreased expression of endothelial signature genes.

CONCLUSIONS

By maintaining a quiescent endothelial phenotype, the polarity protein Scrib elicits anti-atherosclerotic functions.

How do Uremic Toxins Affect the Endothelium?

Uremic toxins can induce endothelial dysfunction in patients with chronic kidney disease (CKD). Indeed, the structure of the endothelial monolayer is damaged in CKD, and studies have shown that the uremic toxins contribute to the loss of cell–cell junctions, increasing permeability. Membrane proteins, such as transporters and receptors, can mediate the interaction between uremic toxins and endothelial cells. In these cells, uremic toxins induce oxidative stress and activation of signaling pathways, including the aryl hydrocarbon receptor (AhR), nuclear factor kappa B (NF-κB), and mitogen-activated protein kinase (MAPK) pathways. The activation of these pathways leads to overexpression of proinflammatory (e.g., monocyte chemoattractant protein-1, E-selectin) and prothrombotic (e.g., tissue factor) proteins. Uremic toxins also induce the formation of endothelial microparticles (EMPs), which can lead to the activation and dysfunction of other cells, and modulate the expression of microRNAs that have an important role in the regulation of cellular processes. The resulting endothelial dysfunction contributes to the pathogenesis of cardiovascular diseases, such as atherosclerosis and thrombotic events. Therefore, uremic toxins as well as the pathways they modulated may be potential targets for therapies in order to improve treatment for patients with CKD.

Evaluation of the role of Nrf2/Keap1 pathway-associated novel mutations and gene expression on antioxidant status in patients with deep vein thrombosis

Deep vein thrombosis (DVT) is a type of venous thromboembolism and a clinically complex vascular disease. Oxidative stress serves a key role in the pathogenesis of numerous cardiovascular diseases, particularly in endothelial dysfunction-associated syndromes. Nuclear factor erythroid-2-like 2(Nrf2) transcription factor is the primary regulator of antioxidant responses. The levels of reactive oxygen species (ROS) are regulated by Nrf2 and its suppressor protein Kelch-like ECH-associated protein 1 (Keap1). However, to the best of our knowledge, genetic abnormalites in the Nrf2/Keap1 pathway in DVT syndrome have not been thoroughly investigated. The aim of the present study was to investigate the association between the Nrf2/Keap1 pathway and antioxidant responses in DVT. Mutations and expression levels of genes involved in the Nrf2/Keap1 pathway were measured in 27 patients with DVT via DNA sequencing analysis and reverse transcription-quantitative PCR, respectively. The Polymorphism Phenotyping v2 program was used to identify the pathogenic mutations. Total antioxidant activity levels were determined by measuring the effect of serum samples from 27 patients with DVT on oxidation of the 2,2'-azino-bis (3-ethylbenz-thiazoline-6-sulfonic acid) system. A total of 23 mutations, including seven novel mutations, were detected in the Nrf2/Keap1 pathway in 24 (89%) of the 27 patients with DVT. Keap1 mRNA expression levels were significantly higher compared with Nrf2 expression levels in patients with DVT (P=0.02). Analysis of molecular characteristics and gene expression levels demonstrated that Nrf2/Keap1-associated mutations and total antioxidant levels can be used as precursor markers in the diagnosis of DVT.

Identification of microRNAs involved in NOD-dependent induction of pro-inflammatory genes in pulmonary endothelial cells

The nucleotide-binding oligomerization domain-containing proteins (NOD) 1 and 2 are mammalian cytosolic pattern recognition receptors sensing bacterial peptidoglycan fragments in order to initiate cytokine expression and pathogen host defense. Since endothelial cells are relevant cells for pathogen recognition at the blood/tissue interface, we here analyzed the role of NOD1- and NOD2-dependently expressed microRNAs (miRNAs, miR) for cytokine regulation in murine pulmonary endothelial cells. The induction of inflammatory cytokines in response to NOD1 and NOD2 was confirmed by increased expression of tumour necrosis factor (Tnf)-α and interleukin (Il)-6. MiRNA expression profiling revealed NOD1- and NOD2-dependently regulated miRNA candidates, of which miR-147-3p, miR-200a-3p, and miR-298-5p were subsequently validated in pulmonary endothelial cells isolated from Nod1/2-deficient mice. Analysis of the two down-regulated candidates miR-147-3p and miR-298-5p revealed predicted binding sites in the 3' untranslated region (UTR) of the murine Tnf-α and Il-6 mRNA. Consequently, transfection of endothelial cells with miRNA mimics decreased Tnf-α and Il-6 mRNA levels. Finally, a novel direct interaction of miR-298-5p with the 3' UTR of the Il-6 mRNA was uncovered by luciferase reporter assays. We here identified a mechanism of miRNA-down-regulation by NOD stimulation thereby enabling the induction of inflammatory gene expression in endothelial cells.

[Application of mathematical modeling methods in the evaluation of severity of ischemic stroke in patients with arterial hypertension]

AIM

To study the possibility of applying methods of mathematical modeling in assessing the severity of ischemic stroke in patients with arterial hypertension.

MATERIAL AND METHODS

The study included 80 patients with ischemic stroke. Blood pressure was measured. Transcutaneous polarography was used to measure the oxygen tension in tissues. Measurements of gas composition of the blood and thickness of the intima-media complex were performed. The level of stable metabolites of nitric oxide in the blood was determined. Measurement of endothelin-1 in the blood was performed by enzyme immunoassay. NIHSS scale was administered to assess the neurological status. Patients were divided into 3 groups according to the degree of neurological deficit. The control group consisted of 10 people without signs of vascular pathology.

RESULTS

An increase in the neurological deficit was accompanied by an increase in the level of endothelin-1, a decrease in the level of stable metabolites of nitric oxide, and a reduction in tissue oxygenation. Discriminative functions were developed for each group of patients using discriminant analysis based on the data obtained in the study. The most statistically significant were two signs: the level of systolic blood pressure and the content of stable metabolites of nitric oxide in the blood.

CONCLUSION

Thus, the imbalance in the indices of endothelium-dependent mechanisms of vascular tone regulation reflect the severity of the condition in ischemic stroke. The method of discriminant analysis allows the creation of sufficiently reliable mathematical models that can have practical significance, and can be used as a method of clarifying the severity of the condition in the acute period of ischemic stroke.