A selective microRNA-based strategy inhibits restenosis while preserving endothelial function

Endothelial microRNAs in INOCA patients with diabetes mellitus

Ischemia with non-obstructive coronary artery (INOCA) is a common cause of hospital admissions, leading to negative outcomes and reduced quality of life. Central to its pathophysiology is endothelial dysfunction, which contributes to myocardial ischemia despite the absence of significant coronary artery blockage. Addressing endothelial dysfunction is essential in managing INOCA to alleviate symptoms and prevent cardiovascular events. Recent studies have identified diabetes mellitus (DM) as a significant factor exacerbating INOCA complications by promoting endothelial impairment and coronary microvascular dysfunction. MicroRNAs (miRNAs) have emerged as potential biomarkers and therapeutic targets in various biological processes, including endothelial dysfunction and cardiovascular diseases. However, research on miRNA biomarkers in INOCA patients is sparse. In this study, we examined a panel of circulating miRNAs involved in the regulation of endothelial function in INOCA patients with and without DM. We analyzed miRNA expression using RT-qPCR in a cohort of consecutive INOCA patients undergoing percutaneous coronary intervention. We detected a significant dysregulation of miR-363-5p and miR-92a-3p in INOCA patients with DM compared to those without DM, indicating their role as biomarkers for predicting and monitoring endothelial dysfunction in INOCA patients with DM.

Endovascular Drug Delivery

Drug-eluting stents (DES) and balloons revolutionize atherosclerosis treatment by targeting hyperplastic tissue responses through effective local drug delivery strategies. This review examines approved and emerging endovascular devices, discussing drug release mechanisms and their impacts on arterial drug distribution. It emphasizes the crucial role of drug delivery in modern cardiovascular care and highlights how device technologies influence vascular behavior based on lesion morphology. The future holds promise for lesion-specific treatments, particularly in the superficial femoral artery, with recent CE-marked devices showing encouraging results. Exciting strategies and new patents focus on local drug delivery to prevent restenosis, shaping the future of interventional outcomes. In summary, as we navigate the ever-evolving landscape of cardiovascular intervention, it becomes increasingly evident that the future lies in tailoring treatments to the specific characteristics of each lesion. By leveraging cutting-edge technologies and harnessing the potential of localized drug delivery, we stand poised to usher in a new era of precision medicine in vascular intervention.

Fasting blood glucose predicts high risk of in-stent restenosis in patients undergoing primary percutaneous coronary intervention: a cohort study

Objectives. Studies have shown that fasting blood glucose (FBG) is closely associated with poor prognosis in patients with coronary heart disease (CHD) after percutaneous coronary intervention (PCI), but its association with in-stent restenosis (ISR) is still unclear. Therefore, this study was to explore the association between FBG with ISR in patients with CHD after PCI. Design. In this cohort study, we included 531 patients with CHD who underwent PCI. Logistic regression, receiver operating characteristic (ROC), subgroup analysis and restricted cubic spline (RCS) were used to assess the association between FBG with ISR. Results. A total of 124 (23.4%) patients had ISR. Patients with higher levels of FBG had higher incidence of ISR compared to those with lower levels of FBG (p = 0.002). In multivariable logistic regression analyses, higher levels of FBG remained strongly associated with higher risk of ISR (as a categorical variable, OR: 1.89, 95% CI: 1.21-2.94, p = 0.005; as a continuous variable, OR: 1.12, 95% CI: 1.03-1.23, p = 0.011). ROC analysis also showed that FBG might be associated with the occurrence of ISR (AUC = 0.577, 95% CI: 0.52-0.64, p = 0.013). Subgroup analyses showed the association of FBG with ISR was also stable in several subgroups (< 60 years or ≥ 60 years, male, with or without smoking, without diabetes and without hypertension). And RCS analysis showed that FBG was linearly and positively associated with the risk of ISR. Conclusions. Higher levels of FBG were closely associated with higher risk of ISR in patients with CHD after PCI.

Advancement in Cellular Topographic and Nanoparticle Capture Imaging by High Resolution Microscopy Incorporating a Freeze-Drying and Gaseous Nitrogen-based Approach

Scanning electron microscopy (SEM) offers an unparalleled view of the membrane topography of mammalian cells by using a conventional osmium (OsO4) and ethanol-based tissue preparation. However, conventional SEM methods limit optimal resolution due to ethanol and lipid interactions and interfere with visualization of fluorescent reporter proteins. Therefore, SEM correlative light and electron microscopy (CLEM) has been hindered by the adverse effects of ethanol and OsO4 on retention of fluorescence signals. To overcome this technological gap in achieving high-resolution SEM and retain fluorescent reporter signals, we developed a freeze-drying method with gaseous nitrogen (FDGN). We demonstrate that FDGN preserves cyto-architecture to allow visualization of detailed membrane topography while retaining fluorescent signals and that FDGN processing can be used in conjunction with a variety of high-resolution imaging systems to enable collection and validation of unique, high-quality data from these approaches. In particular, we show that FDGN coupled with high resolution microscopy provided detailed insight into viral or tumor-derived extracellular vesicle (TEV)-host cell interactions and may aid in designing new approaches to intervene during viral infection or to harness TEVs as therapeutic agents.

miR-181c targets Parkin and SMAD7 in human cardiac fibroblasts: Validation of differential microRNA expression in patients with diabetes and heart failure with preserved ejection fraction

BACKGROUND

Cardiac fibrosis represents a key feature in the pathophysiology of heart failure with preserved ejection fraction (HFpEF), a condition highly prevalent amongst geriatric patients, especially if diabetic. The microRNA miR-181c has been shown to be associated with the response to exercise training in HFpEF patients and has been also linked to diabetic cardiovascular complications. However, the underlying mechanisms have not been fully elucidated.

OBJECTIVE

To measure circulating miR-181c in elderly patients with HFpEF and DM and identify gene targets pathophysiologically relevant in HFpEF.

METHODS

We quantified circulating miR-181c in frail older adults with a confirmed diagnosis of HFpEF and diabetes, and, as control, we enrolled age-matched subjects without HFpEF and without diabetes. We validated in human cardiac fibroblasts the molecular mechanisms linking miR-181c to a pro-fibrotic response.

RESULTS

51 frail patients were included (34 patients with diabetes and HFpEF and 17 age-matched controls. We observed that miR-181c was significantly upregulated (p<0.0001) in HFpEF patients vs controls. We confirmed in vitro that miR-181c is targeting PRKN and SMAD7.

CONCLUSIONS

We demonstrate that miR-181c levels are significantly increased in frail elderly adults with diabetes and HFpEF and that miR-181c targets PRKN and SMAD7 in human cardiac fibroblasts.

Experimental evidence and clinical implications of Warburg effect in the skeletal muscle of Fabry disease

Skeletal muscle (SM) pain and fatigue are common in Fabry disease (FD). Here, we undertook the investigation of the energetic mechanisms related to FD-SM phenotype. A reduced tolerance to aerobic activity and lactate accumulation occurred in FD-mice and patients. Accordingly, in murine FD-SM we detected an increase in fast/glycolytic fibers, mirrored by glycolysis upregulation. In FD-patients, we confirmed a high glycolytic rate and the underutilization of lipids as fuel. In the quest for a tentative mechanism, we found HIF-1 upregulated in FD-mice and patients. This finding goes with miR-17 upregulation that is responsible for metabolic remodeling and HIF-1 accumulation. Accordingly, miR-17 antagomir inhibited HIF-1 accumulation, reverting the metabolic-remodeling in FD-cells. Our findings unveil a Warburg effect in FD, an anaerobic-glycolytic switch under normoxia induced by miR-17-mediated HIF-1 upregulation. Exercise-intolerance, blood-lactate increase, and the underlying miR-17/HIF-1 pathway may become useful therapeutic targets and diagnostic/monitoring tools in FD.

miR-4432 Targets FGFBP1 in Human Endothelial Cells

MicroRNAs (miRs) are small non-coding RNAs that modulate the expression of several target genes. Fibroblast growth factor binding protein 1 (FGFBP1) has been associated with endothelial dysfunction at the level of the blood-brain barrier (BBB). However, the underlying mechanisms are mostly unknown and there are no studies investigating the relationship between miRs and FGFBP1. Thus, the overarching aim of the present study was to identify and validate which miR can specifically target FGFBP1 in human brain microvascular endothelial cells, which represent the best in vitro model of the BBB. We were able to identify and validate miR-4432 as a fundamental modulator of FGFBP1 and we demonstrated that miR-4432 significantly reduces mitochondrial oxidative stress, a well-established pathophysiological hallmark of hypertension.

Drug loaded implantable devices to treat cardiovascular disease

INTRODUCTION

It is widely acknowledged that cardiovascular diseases (CVDs) continue to be the leading cause of death globally. Furthermore, CVDs are the leading cause of diminished quality of life for patients, frequently as a result of their progressive deterioration. Medical implants that release drugs into the body are active implants that do more than just provide mechanical support; they also have a therapeutic role. Primarily, this is achieved through the controlled release of active pharmaceutical ingredients (API) at the implementation site.

AREAS COVERED

In this review, the authors discuss drug-eluting stents, drug-eluting vascular grafts, and drug-eluting cardiac patches with the aim of providing a broad overview of the three most common types of cardiac implant.

EXPERT OPINION

Drug eluting implants are an ideal alternative to traditional drug delivery because they allow for accurate drug release, local drug delivery to the target tissue, and minimise the adverse side effects associated with systemic administration. Despite the fact that there are still challenges that need to be addressed, the ever-evolving new technologies are making the fabrication of drug eluting implants a rewarding therapeutic endeavour with the possibility for even greater advances.

COVID-19 Causes Ferroptosis and Oxidative Stress in Human Endothelial Cells

Oxidative stress and endothelial dysfunction have been shown to play crucial roles in the pathophysiology of COVID-19 (coronavirus disease 2019). On these grounds, we sought to investigate the impact of COVID-19 on lipid peroxidation and ferroptosis in human endothelial cells. We hypothesized that oxidative stress and lipid peroxidation induced by COVID-19 in endothelial cells could be linked to the disease outcome. Thus, we collected serum from COVID-19 patients on hospital admission, and we incubated these sera with human endothelial cells, comparing the effects on the generation of reactive oxygen species (ROS) and lipid peroxidation between patients who survived and patients who did not survive. We found that the serum from non-survivors significantly increased lipid peroxidation. Moreover, serum from non-survivors markedly regulated the expression levels of the main markers of ferroptosis, including GPX4, SLC7A11, FTH1, and SAT1, a response that was rescued by silencing TNFR1 on endothelial cells. Taken together, our data indicate that serum from patients who did not survive COVID-19 triggers lipid peroxidation in human endothelial cells.

Empagliflozin Improves the MicroRNA Signature of Endothelial Dysfunction in Patients with Heart Failure with Preserved Ejection Fraction and Diabetes

Endothelial dysfunction represents a key mechanism underlying heart failure with preserved ejection fraction (HFpEF), diabetes mellitus (DM), and frailty. However, reliable biomarkers to monitor endothelial dysfunction in these patients are lacking. In this study, we evaluated the expression of a panel of circulating microRNAs (miRs) involved in the regulation of endothelial function in a population of frail older adults with HFpEF and DM treated for 3 months with empagliflozin, metformin, or insulin. We identified a distinctive pattern of miRs that were significantly regulated in HFpEF patients compared to healthy controls and to HFpEF patients treated with the sodium glucose cotransporter 2 (SGLT2) inhibitor empagliflozin. Three miRs were significantly downregulated (miR-126, miR-342-3p, and miR-638) and two were significantly upregulated (miR-21 and miR-92) in HFpEF patients compared to healthy controls. Strikingly, two of these miRs (miR-21 and miR-92) were significantly reduced in HFpEF patients after the 3-month treatment with empagliflozin, whereas no significant differences in the profile of endothelial miRs were detected in patients treated with metformin or insulin. Taken together, our findings demonstrate for the first time that specific circulating miRs involved in the regulation of endothelial function are significantly regulated in frail HFpEF patients with DM and in response to SGLT2 inhibition. SIGNIFICANCE STATEMENT: We have identified a novel microRNA signature functionally involved in the regulation of endothelial function that is significantly regulated in frail patients with HFpEF and diabetes. Moreover, the treatment with the SGLT2 inhibitor empagliflozin caused a modification of some of these microRNAs in a direction that was opposite to what observed in HFpEF patients, indicating a rescue of endothelial function. Our findings are relevant for clinical practice inasmuch as we were able to establish novel biomarkers of disease and response to therapy.

Inflammatory Phenotype by OCT Coronary Imaging: Specific Features Among De Novo Lesions, In-Stent Neointima, and In-Stent Neo-Atherosclerosis

BACKGROUND

Coronary stenosis can be caused de novo atherosclerosis, in-stent restenosis, and in-stent neoatherosclerosis, three entities that develop from a diverse pathophysiological milieu.

OBJECTIVE

This study aims to investigate, using optical coherence tomography (OCT), whether or not coronary lesions related to these processes differ in their local inflammatory profile.

METHODS

Retrospective analysis of patients with diagnosed or suspected coronary lesions who had undergone OCT imaging for clinical reasons. Macrophage and intra-plaque neovascularization were assessed by OCT and used as surrogates of local inflammation. A significance level of < 0.05 was adopted as statistically significant.

RESULTS

From the 121 lesions, 74 were de novo, 29 were restenosis, and 18 were neoatherosclerosis. Neovascularization was found in 65.8% of de novo, 10.3% in restenosis, and 94.4% in neoatherosclerosis (p<0.01 for all). The volume of neovascularization was different among lesion types (950 vs. 0 vs. 6220, respectively [median values in 1000 x µm3/mm]; p<0.01 for all), which were significantly higher in neoatherosclerosis and lower in restenosis. The presence of macrophages differed among the lesions (95.9% in de novo vs. 6.9% in restenosis vs. 100% in neoatherosclerosis [p<0.01 for all]). Moreover, the intensity of macrophagic infiltration was different among lesion types (2.5 vs. 0.0 vs. 4.5, respectively [median values of macrophage score]; p<0.01 for all), significantly higher in neoatheroscleosis and lower in restenosis.

CONCLUSION

When compared using coronary OCT, de novo atherosclerosis, in-stent restenosis, and neoatherosclerosis presented markedly different inflammatory phenotypes.

Anti-atherosclerotic therapies: Milestones, challenges, and emerging innovations

Atherosclerosis is the main underlying pathology for many cardiovascular diseases (CVDs), which are the leading cause of death globally and represent a serious health crisis. Atherosclerosis is a chronic condition that can lead to myocardial infarction, ischemic cardiomyopathy, stroke, and peripheral arterial disease. Elevated plasma lipids, hypertension, and high glucose are the major risk factors for developing atherosclerotic plaques. To date, most pharmacological therapies aim to control these risk factors, but they do not target the plaque-causing cells themselves. In patients with acute coronary syndromes, surgical revascularization with percutaneous coronary intervention has greatly reduced mortality rates. However, stent thrombosis and neo-atherosclerosis have emerged as major safety concerns of drug eluting stents due to delayed re-endothelialization. This review summarizes the major milestones, strengths, and limitations of current anti-atherosclerotic therapies. It provides an overview of the recent discoveries and emerging game-changing technologies in the fields of nanomedicine, mRNA therapeutics, and gene editing that have the potential to revolutionize CVD clinical practice by steering it toward precision medicine.

miR-142 Targets TIM-1 in Human Endothelial Cells: Potential Implications for Stroke, COVID-19, Zika, Ebola, Dengue, and Other Viral Infections

T-cell immunoglobulin and mucin domain 1 (TIM-1) has been recently identified as one of the factors involved in the internalization of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in human cells, in addition to angiotensin-converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2), neuropilin-1, and others. We hypothesized that specific microRNAs could target TIM-1, with potential implications for the management of patients suffering from coronavirus disease 2019 (COVID-19). By combining bioinformatic analyses and functional assays, we identified miR-142 as a specific regulator of TIM-1 transcription. Since TIM-1 has been implicated in the regulation of endothelial function at the level of the blood-brain barrier (BBB) and its levels have been shown to be associated with stroke and cerebral ischemia-reperfusion injury, we validated miR-142 as a functional modulator of TIM-1 in human brain microvascular endothelial cells (hBMECs). Taken together, our results indicate that miR-142 targets TIM-1, representing a novel strategy against cerebrovascular disorders, as well as systemic complications of SARS-CoV-2 and other viral infections.

Cardiac Remodeling After Myocardial Infarction: Functional Contribution of microRNAs to Inflammation and Fibrosis

After an ischemic injury, the heart undergoes a complex process of structural and functional remodeling that involves several steps, including inflammatory and fibrotic responses. In this review, we are focusing on the contribution of microRNAs in the regulation of inflammation and fibrosis after myocardial infarction. We summarize the most updated studies exploring the interactions between microRNAs and key regulators of inflammation and fibroblast activation and we discuss the recent discoveries, including clinical applications, in these rapidly advancing fields.

Pathophysiology of Atherosclerosis

Atherosclerosis is the main risk factor for cardiovascular disease (CVD), which is the leading cause of mortality worldwide. Atherosclerosis is initiated by endothelium activation and, followed by a cascade of events (accumulation of lipids, fibrous elements, and calcification), triggers the vessel narrowing and activation of inflammatory pathways. The resultant atheroma plaque, along with these processes, results in cardiovascular complications. This review focuses on the different stages of atherosclerosis development, ranging from endothelial dysfunction to plaque rupture. In addition, the post-transcriptional regulation and modulation of atheroma plaque by microRNAs and lncRNAs, the role of microbiota, and the importance of sex as a crucial risk factor in atherosclerosis are covered here in order to provide a global view of the disease.

IP3 receptor orchestrates maladaptive vascular responses in heart failure

Patients with heart failure (HF) have augmented vascular tone, which increases cardiac workload, impairing ventricular output and promoting further myocardial dysfunction. The molecular mechanisms underlying the maladaptive vascular responses observed in HF are not fully understood. Vascular smooth muscle cells (VSMCs) control vasoconstriction via a Ca²⁺-dependent process, in which the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1) on the sarcoplasmic reticulum (SR) plays a major role. To dissect the mechanistic contribution of intracellular Ca²⁺ release to the increased vascular tone observed in HF, we analyzed the remodeling of IP3R1 in aortic tissues from patients with HF and from controls. VSMC IP3R1 channels from patients with HF and HF mice were hyperphosphorylated by both serine and tyrosine kinases. VSMCs isolated from IP3R1^VSMC–/– mice exhibited blunted Ca²⁺ responses to angiotensin II (ATII) and norepinephrine compared with control VSMCs. IP3R1^VSMC–/– mice displayed significantly reduced responses to ATII, both in vivo and ex vivo. HF IP3R^1VSMC–/– mice developed significantly less afterload compared with HF IP3R1^fl/fl mice and exhibited significantly attenuated progression toward decompensated HF and reduced interstitial fibrosis. Ca²⁺-dependent phosphorylation of the MLC by MLCK activated VSMC contraction. MLC phosphorylation was markedly increased in VSMCs from patients with HF and HF mice but reduced in VSMCs from HF IP3R1^VSMC–/– mice and HF WT mice treated with ML-7. Taken together, our data indicate that VSMC IP3R1 is a major effector of increased vascular tone, which contributes to increased cardiac afterload and decompensation in HF.

Diabetes and restenosis

Restenosis, defined as the re-narrowing of an arterial lumen after revascularization, represents an increasingly important issue in clinical practice. Indeed, as the number of stent placements has risen to an estimate that exceeds 3 million annually worldwide, revascularization procedures have become much more common. Several investigators have demonstrated that vessels in patients with diabetes mellitus have an increased risk restenosis. Here we present a systematic overview of the effects of diabetes on in-stent restenosis. Current classification and updated epidemiology of restenosis are discussed, alongside the main mechanisms underlying the pathophysiology of this event. Then, we summarize the clinical presentation of restenosis, emphasizing the importance of glycemic control in diabetic patients. Indeed, in diabetic patients who underwent revascularization procedures a proper glycemic control remains imperative.

A Retinoic Acid Receptor β 2 Agonist Improves Cardiac Function in a Heart Failure Model

We previously demonstrated that the selective retinoic acid receptor (RAR) β ₂ agonist AC261066 reduces oxidative stress in an ex vivo murine model of ischemia/reperfusion. We hypothesized that by decreasing oxidative stress and consequent fibrogenesis, AC261066 could attenuate the development of contractile dysfunction in post-ischemic heart failure (HF). We tested this hypothesis in vivo using an established murine model of myocardial infarction (MI), obtained by permanent occlusion of the left anterior descending coronary artery. Treating mice with AC261066 in drinking water significantly attenuated the post-MI deterioration of echocardiographic indices of cardiac function, diminished remodeling, and reduced oxidative stress, as evidenced by a decrease in malondialdehyde level and p38 mitogen-activated protein kinase expression in cardiomyocytes. The effects of AC261066 were also associated with a decrease in interstitial fibrosis, as shown by a marked reduction in collagen deposition and α-smooth muscle actin expression. In cardiac murine fibroblasts subjected to hypoxia, AC261066 reversed hypoxia-induced decreases in superoxide dismutase 2 and angiopoietin-like 4 transcriptional levels as well as the increase in NADPH oxidase 2 mRNA, demonstrating that the post-MI cardioprotective effects of AC261066 are associated with an action at the fibroblast level. Thus, AC261066 alleviates post-MI cardiac dysfunction by modulating a set of genes involved in the oxidant/antioxidant balance. These AC261066 responsive genes diminish interstitial fibrogenesis and remodeling. Since MI is a recognized major cause of HF, our data identify RARβ ₂ as a potential pharmacological target in the treatment of HF. SIGNIFICANCE STATEMENT: A previous report showed that the selective retinoic acid receptor (RAR) β ₂ agonist AC261066 reduces oxidative stress in an ex vivo murine model of ischemia/reperfusion. This study shows that AC261066 attenuates the development of contractile dysfunction and maladaptive remodeling in post-ischemic heart failure (HF) by modulating a set of genes involved in oxidant/antioxidant balance. Since myocardial infarction is a recognized major cause of HF, these data identify RARβ ₂ as a potential pharmacological target in the treatment of HF.

Roles of MicroRNAs in Peripheral Artery In-Stent Restenosis after Endovascular Treatment

Endovascular repair including percutaneous transluminal angioplasty (PTA) and stent implantation has become the standard approach for the treatment of peripheral arterial disease; however, restenosis is still the main limited complication for the long-term success of the endovascular repair. Endothelial denudation and regeneration, inflammatory response, and neointimal hyperplasia are major pathological processes occurring during in-stent restenosis (ISR). MicroRNAs exhibit great potential in regulating several vascular biological events in different cell types and have been identified as novel therapeutic targets as well as biomarkers for ISR prevention. This review summarized recent experimental and clinical studies on the role of miRNAs in ISR modification, with the aim of unraveling the underlying mechanism and potential therapeutic strategy of ISR.

Role of MicroRNA-145 in DNA Damage Signalling and Senescence in Vascular Smooth Muscle Cells of Type 2 Diabetic Patients

Increased cardiovascular morbidity and mortality in individuals with type 2 diabetes (T2DM) is a significant clinical problem. Despite advancements in achieving good glycaemic control, this patient population remains susceptible to macrovascular complications. We previously discovered that vascular smooth muscle cells (SMC) cultured from T2DM patients exhibit persistent phenotypic aberrancies distinct from those of individuals without a diagnosis of T2DM. Notably, persistently elevated expression levels of microRNA-145 co-exist with characteristics consistent with aging, DNA damage and senescence. We hypothesised that increased expression of microRNA-145 plays a functional role in DNA damage signalling and subsequent cellular senescence specifically in SMC cultured from the vasculature of T2DM patients. In this study, markers of DNA damage and senescence were unambiguously and permanently elevated in native T2DM versus non-diabetic (ND)-SMC. Exposure of ND cells to the DNA-damaging agent etoposide inflicted a senescent phenotype, increased expression of apical kinases of the DNA damage pathway and elevated expression levels of microRNA-145. Overexpression of microRNA-145 in ND-SMC revealed evidence of functional links between them; notably increased secretion of senescence-associated cytokines and chronic activation of stress-activated intracellular signalling pathways, particularly the mitogen-activated protein kinase, p38α. Exposure to conditioned media from microRNA-145 overexpressing cells resulted in chronic p38α signalling in naïve cells, evidencing a paracrine induction and reinforcement of cell senescence. We conclude that targeting of microRNA-145 may provide a route to novel interventions to eliminate DNA-damaged and senescent cells in the vasculature and to this end further detailed studies are warranted.

Potential Target miR-455 Delaying Arterial Stenosis Progression Through PTEN

Background: Vascular smooth muscle cells (VSMC) underwent phenotypic switching upon stimulation signals, and this is the prerequisite for their proliferation and migration. Previous work revealed that miR-455 may be involved in vascular stenosis. Thus, this study aimed to explore potential targets and mechanisms underlying the dynamics of miR-455 in vascular stenosis.

Methods: miR-455 and PTEN expression levels were studied in normal and stenosis tissue, as well as in VSMC in proliferation model. Manipulating miR-455 expression levels was achieved by transfection of either miR-455 mimic or inhibitor, and its effect on cell proliferation was studied by CCK-8 assay. Its effect on gene expression was studied by RT-qPCR and western blot. The expression regulation mechanism was studied by luciferase reporter system. Finally, the effect of miR-455 on regulating vascular stenosis was studied using a rat balloon-injured carotid artery stenosis model.

Results: High expression levels of miR-455 were detected in both stenosis arterial tissues and VSMC proliferation models. In contrast, the expression levels of PTEN were downregulated in these systems. miR-455 transfected VSMC showed higher levels of proliferation and decreased levels of PTEN. Potential binding sites between miR-455 and PTEN 3′UTR were predicted and confirmed. NF-kB p65 was found to bind directly on miR-455 promoter region and regulate its transcription. The progression of arterial stenosis could be delayed by introducing miR-455 antagomir.

Conclusions: The p65/miR-455/PTEN signaling pathway plays a crucial role in regulating VSMC proliferation and vascular stenosis. This indicated that miR-455 is a novel target that would help improve treatment outcomes in patients suffering from vascular stenosis.

Self-assembled miRNA-switch nanoparticles target denuded regions and prevent restenosis

Cardiovascular disease is the leading cause of death and disability worldwide. Effective delivery of cell-selective therapies that target atherosclerotic plaques and neointimal growth while sparing the endothelium remains the Achilles heel of percutaneous interventions. The current study utilizes synthetic microRNA switch therapy that self-assembles to form a compacted, nuclease-resistant nanoparticle <200 nM in size when mixed with cationic amphipathic cell-penetrating peptide (p5RHH). These nanoparticles possess intrinsic endosomolytic activity that requires endosomal acidification. When administered in a femoral artery wire injury mouse model in vivo, the mRNA-p5RHH nanoparticles deliver their payload specifically to the regions of endothelial denudation and not to the lungs, liver, kidney, or spleen. Moreover, repeated administration of nanoparticles containing a microRNA switch, consisting of synthetically modified mRNA encoding for the cyclin-dependent kinase inhibitor p27^Kip1 that contains one complementary target sequence of the endothelial cell-specific miR-126 at its 5' UTR, drastically reduced neointima formation after wire injury and allowed for vessel reendothelialization. This cell-selective nanotherapy is a valuable tool that has the potential to advance the fight against neointimal hyperplasia and atherosclerosis.

miR-24 targets SARS-CoV-2 co-factor Neuropilin-1 in human brain microvascular endothelial cells: Insights for COVID-19 neurological manifestations

Neuropilin-1 is a transmembrane glycoprotein that has been implicated in several processes including angiogenesis and immunity. Recent evidence has also shown that it is implied in the cellular internalization of the severe acute respiratory syndrome coronavirus (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19). We hypothesized that specific microRNAs can target Neuropilin-1. By combining bioinformatic and functional approaches, we identified miR-24 as a regulator of Neuropilin-1 transcription. Since Neuropilin-1 has been shown to play a key role in the endothelium-mediated regulation of the blood-brain barrier, we validated miR-24 as a functional modulator of Neuropilin-1 in human brain microvascular endothelial cells (hBMECs), which are the most suitable cell line for an in vitro bloodâ€"brain barrier model.

miR-24 Targets the Transmembrane Glycoprotein Neuropilin-1 in Human Brain Microvascular Endothelial Cells

Neuropilin-1 is a transmembrane glycoprotein that has been implicated in several processes including angiogenesis and immunity. Recent evidence has also shown that it is implied in the cellular internalization of the severe acute respiratory syndrome coronavirus (SARS-CoV-2), which causes the coronavirus disease 2019 (COVID-19). We hypothesized that specific microRNAs can target Neuropilin-1. By combining bioinformatic and functional approaches, we identified miR-24 as a regulator of Neuropilin-1 transcription. Since Neuropilin-1 has been shown to play a key role in the endothelium-mediated regulation of the blood-brain barrier, we validated miR-24 as a functional modulator of Neuropilin-1 in human brain microvascular endothelial cells (hBMECs), which are the most suitable cell line for an in vitro blood-brain barrier model.

MiR-381-3p redistributes between cytosol and mitochondria and aggravates endothelial cell injury induced by reactive oxygen species

MicroRNAs (miRNAs) are reported to play pivotal roles in reactive oxygen species (ROS)-induced endothelial cell injury and several studies have demonstrated the miRNA distribution in the mitochondria of various cells. However, very little is known about its changes and roles in ROS-induced endothelial cell injury. In the present study, we systematically revealed the distribution changes of miRNAs in mitochondria during ROS-induced endothelial cell injury and found that H₂O₂ obviously reduced the mitochondrial distribution of many miRNAs without affecting their expression levels in the whole endothelial cells. Most of these miRNAs showing reduced mitochondrial distribution were potentially involved in ROS-induced endothelial cell injury. MiR-381-3p was a typical representative of these miRNAs and its redistribution between mitochondria and cytosol regulated the network consisting of downstream molecules (P53, P21, CCND1, and MYC) by inhibiting its target genes (LRP6 and NFIA) to promote apoptosis and inhibit proliferation in endothelial cells. Our findings highlight the significance of redistribution of miRNAs between mitochondria and cytosol and improve our understanding of miRNA function regulation.

Circulating miRNA-23b and miRNA-143 Are Potential Biomarkers for In-Stent Restenosis

In-stent restenosis (ISR) is one of the main complications in patients undergoing percutaneous coronary angioplasty, and microRNAs participate in the contractile-to-synthetic phenotypic switch of vascular smooth muscle cells, a hallmark of restenosis development. MicroRNAs (miRNAs) can be released into circulation from injured tissues, enticing a potential role as noninvasive biomarkers. We aimed to evaluate circulating levels of miRNA-23b, miRNA-143, and miRNA-145 as diagnostic markers of ISR. 142 patients with coronary artery disease undergoing successful angioplasty and a follow-up angiography were included. Subjects were classified according to the degree of obstruction at the angioplasty site into cases (≥50%) or controls (<50%). Total RNA was isolated from plasma to quantify circulating miRNAs levels, and the ROC curves were constructed. Among circulating miRNAs assessed, miRNA-23b and miRNA-143 were significantly lower in cases (miRNA-23b: 18.4x10⁻⁵ and miRNA-143: 13.7x10⁻⁵) than controls (miRNA-23b: 5.2x10⁻⁵, p < 0.0001; miRNA-143: 4.0x10⁻⁵, p < 0.0001). Plasma levels of miRNA-145 showed no significant differences. The analysis of the ROC curves showed an area under the curve for miRNA-23b of 0.71 (95% CI: 0.62-0.80, p < 0.0001) and 0.69 for miRNA-143 (95% CI: 0.60-0.78; p < 0.0001). Our data suggest that plasma levels of miRNA-23b and miRNA-143 could be useful as noninvasive biomarkers of ISR.

miR-7 Regulates GLP-1-Mediated Insulin Release by Targeting β-Arrestin 1

Glucagon-like peptide-1 (GLP-1) has been shown to potentiate glucose-stimulated insulin secretion binding GLP-1 receptor on pancreatic β cells. β-arrestin 1 (βARR1) is known to regulate the desensitization of GLP-1 receptor. Mounting evidence indicates that microRNAs (miRNAs, miRs) are fundamental in the regulation of β cell function and insulin release. However, the regulation of GLP-1/βARR1 pathways by miRs has never been explored. Our hypothesis is that specific miRs can modulate the GLP-1/βARR1 axis in β cells. To test this hypothesis, we applied a bioinformatic approach to detect miRs that could target βARR1; we identified hsa-miR-7-5p (miR-7) and we validated the specific interaction of this miR with βARR1. Then, we verified that GLP-1 was indeed able to regulate the transcription of miR-7 and βARR1, and that miR-7 significantly regulated GLP-1-induced insulin release and cyclic AMP (cAMP) production in β cells. Taken together, our findings indicate, for the first time, that miR-7 plays a functional role in the regulation of GLP-1-mediated insulin release by targeting βARR1. These results have a decisive clinical impact given the importance of drugs modulating GLP-1 signaling in the treatment of patients with type 2 diabetes mellitus.

Durable polymer everolimus-eluting stents: history, current status and future prospects

INTRODUCTION

Coronary percutaneous interventions have evolved from plain old balloon angioplasty (POBA) to stent implantation, which itself evolved from bare-metal stents (BMS) to the new biodegradable stents which try to restore endothelial function. Currently, the most commonly used stent is the everolimus-eluting stent.

AREAS COVERED

This review will cover the current status of durable polymer everolimus-eluting stent, its history, and future perspectives. Nowadays, the everolimus-eluting stent is the most used device in the acute and chronic settings due to its safety and efficacy.

EXPERT OPINION

Durable polymer everolimus-eluting stent, supported by much evidence, has demonstrated its efficacy and safety, not only in de novo artery lesions, but in multiples scenarios, such as the acute setting and diabetic population, becoming one of the most polyvalent stents available. Nowadays, research is focused on the reduction of antiplatelet treatment duration. Similar rates of stent thrombosis with short dual antiplatelet treatment regimens of 1 to 3 months compared to pronged treatment have been observed. However, specific studies should be performed to evaluate this possibility.

A potential strategy for in-stent restenosis: Inhibition of migration and proliferation of vascular smooth muscle cells by Cu ion

The in-stent restenosis (ISR) often happens after the implantation of metal stents, including both bare metal stents (BMSs) and drug-eluting stents (DESs). Drug release from DESs could reduce significantly the occurrence of ISR but also suppress the revascularization and cause thrombosis. In this study, the effect of Cu ion in a range of 0 to 500 μM on the migration and proliferation of rat aortic smooth muscle cells (RASMCs) was investigated by a series of in vitro experiments including wound-healing assay, cell viability assay and flow cytometric analysis. It has been found that the critical concentration of Cu ion should be at least 250 μM in order to significantly inhibit the migration of RASMCs and the proliferation of RASMCs were impeded by every dose of Cu ion used in this study. In addition, the protein level of caspase-3 was upregulated by 250 μM and 500 μM Cu²⁺ exposure, which might be the main reason for RASMCs apoptosis. Thus, it is proposed that ISR might be prevented by the constant release of Cu ion.

Cardiomyocyte-derived exosomal microRNA-92a mediates post-ischemic myofibroblast activation both in vitro and ex vivo

Aims

We hypothesize that specific microRNAs (miRNAs) within cardiomyocyte‐derived exosomes play a pivotal role in the phenoconversion of cardiac myofibroblasts following myocardial infarction (MI).

Methods and results

We used an established murine model of MI, obtained in vivo via ligation of the left anterior descending coronary artery. We isolated adult cardiomyocytes and fibroblasts, and we assessed the functional role of cardiomyocyte‐derived exosomes and their molecular cargo in the activation of cardiac fibroblasts. We identified and biologically validated miR‐92a as a transcriptional regulator of mothers against DPP homologues 7 (SMAD7), a known inhibitor of α‐smooth muscle actin (α‐SMA), established marker of myofibroblast activation. We found that miR‐92a was significantly (P < 0.05) upregulated in cardiomyocyte‐derived exosomes and in fibroblasts isolated after MI compared with SHAM conditions (n ≥ 6/group). We tested the activation of myofibroblasts by measuring the expression levels of αSMA, periostin, and collagen. Primary isolated cardiac fibroblasts were activated both when incubated with cardiomyocyte‐derived exosomes isolated from ischemic cardiomyocytes and when cultured in conditioned medium of post‐MI cardiomyocytes, whereas no significant difference was observed following incubation with exosomes or medium from sham cardiomyocytes. These effects were attenuated when an inhibitor of exosome secretion, GW4869 (10 μM for 12 h) was included in the experimental setting. Through means of specific miR‐92a mimic and miR‐92a inhibitor, we also verified the mechanistic contribution of miR‐92a to the activation of cardiac fibroblasts.

Conclusions

Our results indicate for the first time that miR‐92a is transferred to fibroblasts in form of exosomal cargo and is critical for cardiac myofibroblast activation.

Platelets in In-stent Restenosis: From Fundamental Role to Possible Prognostic Application

BACKGROUND

Introduction of new generations of stents has decreased the percentage of patients experiencing in-stent restenosis (ISR) following the implantation of stent. However, a large number of patients are still afflicted with this phenomenon, which necessitates further study of ISR pathophysiology.

METHODS

Relevant English literature was searched up to 2018 and retrieved form the PubMed database and Google Scholar search engine. The following keywords were used: "In-stent restenosis", "Platelet", "Chemokine", "Inflammation", "Vascular smooth muscle cell" and "Neointima".

RESULTS

Previous studies have shown that ISR is a pathophysiologic response to damage of the artery wall after its elongation and separation of the atherosclerotic plaque. Development of neointimal hyperplasia (NIH) following this pathophysiologic response is a function of inflammation caused by platelets, monocytes, macrophages, and lymphocytes, as well as rapid migration and proliferation of generally quiescent cells in the median layer of the artery wall.

CONCLUSION

After damage to the artery wall, platelets play an essential role in the incidence of NIH by contributing to inflammation and migration of vascular smooth muscle cells and extracellular matrix remodeling, especially via secretion of different chemokines; therefore, developing therapeutic strategies for platelet inhibition in a controlled manner could be the basis of preventive treatments in the near future. In this study, for the first time, we hypothesize that evaluation of platelet activity profile in patients before and after stent implantation may determine the prognosis and likelihood of ISR.

Cardiosomal microRNAs Are Essential in Post-Infarction Myofibroblast Phenoconversion

The inclusion of microRNAs (miRNAs) in extracellular microvesicles/exosomes (named cardiosomes when deriving from cardiomyocytes) allows their active transportation and ensures cell-cell communication. We hypothesize that cardiosomal miRNAs play a pivotal role in the activation of myofibroblasts following ischemic injury. Using a murine model of myocardial infarction (MI), we tested our hypothesis by measuring in isolated fibroblasts and cardiosomes the expression levels of a set of miRNAs, which are upregulated in cardiomyocytes post-MI and involved in myofibroblast phenoconversion. We found that miR-195 was significantly upregulated in cardiosomes and in fibroblasts isolated after MI compared with SHAM conditions. Moreover, primary isolated cardiac fibroblasts were activated both when incubated with cardiosomes isolated from ischemic cardiomyocytes and when cultured in conditioned medium of post-MI cardiomyocytes, whereas no significant effect was observed following incubation with cardiosomes or medium from sham cardiomyocytes. Taken together, our findings indicate for the first time that a cardiomyocyte-specific miRNA, transferred to fibroblasts in form of exosomal cargo, is crucial in the activation of myofibroblasts.

Adenosine, Via A2B Receptors, Inhibits Human (P-SMC) Progenitor Smooth Muscle Cell Growth

c-Kit+ progenitor smooth muscle cells (P-SMCs) can develop into SMCs that contribute to injury-induced neointimal thickening. Here, we investigated whether adenosine reduces P-SMC migration and proliferation and whether this contributes to adenosine's inhibitory actions on neointima formation. In human P-SMCs, 2-chloroadenosine (stable adenosine analogue) and BAY60-6583 (A_2B agonist) inhibited P-SMC proliferation and migration. Likewise, increasing endogenous adenosine by blocking adenosine metabolism with erythro-9-(2-hydroxy-3-nonyl) adenine (inhibits adenosine deaminase) and 5-iodotubercidin (inhibits adenosine kinase) attenuated P-SMC proliferation and migration. Neither N⁶-cyclopentyladenosine (A₁ agonist), CGS21680 (A_2A agonist), nor N⁶-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (A₃ agonist) affected P-SMC proliferation or migration. 2-Chloroadenosine increased cyclic AMP, reduced Akt phosphorylation (activates cyclin D expression), and reduced levels of cyclin D1 (promotes cell-cycle progression). Moreover, 2-chloroadenosine inhibited expression of Skp2 (promotes proteolysis of p27^Kip1) and upregulated levels of p27^Kip1 (negative cell-cycle regulator). A_2B receptor knockdown prevented the effects of 2-chloroadenosine on cyclic AMP production and P-SMC proliferation and migration. Likewise, inhibition of adenylyl cyclase and protein kinase A rescued P-SMCs from the inhibitory effects of 2-chloroadenosine. The inhibitory effects of adenosine were similar in male and female P-SMCs. In vivo, peri-arterial (rat carotid artery) 2-chloroadenosine (20 μmol/L for 7 days) reduced neointimal hyperplasia by 64.5% (P<0.05; intima/media ratio: control, 1.4±0.02; treated, 0.53±0.012) and reduced neointimal c-Kit+ cells. Adenosine inhibits P-SMC migration and proliferation via the A_2B receptor/cyclic AMP/protein kinase A axis, which reduces cyclin D1 expression and activity via inhibiting Akt phosphorylation and Skp2 expression and upregulating p27^kip1 levels. Adenosine attenuates neointima formation in part by inhibiting infiltration and proliferation of c-Kit+ P-SMCs.

MicroRNA-24 inhibits the oxidative stress induced by vascular injury by activating the Nrf2/Ho-1 signaling pathway

BACKGROUND AND AIMS

The process of endothelial repair in diabetic patients after stent implantation was significantly delayed compared with that in non-diabetic patients, and oxidative stress is increasingly considered to be relevant to the pathogenesis of diabetic endothelial repair. However, the mechanisms linking diabetes and reendothelialization after vascular injury have not been fully elucidated. The aim of this study was to evaluate the effect of microRNA-24 (miR-24) up-regulation in delayed endothelial repair caused by oxidative stress after balloon injury in diabetic rats.

METHODS

In vitro, vascular smooth muscle cells (VSMCs) isolated from the thoracic aorta were stimulated with high glucose (HG) after miR-24 recombinant adenovirus (Ad-miR-24-GFP) transfection for 3 days. In vivo, diabetic rats induced using high-fat diet (HFD) and low-dose streptozotocin (30 mg/kg) underwent carotid artery balloon injury followed by Ad-miR-24-GFP transfection for 20 min.

RESULTS

The expression of miR-24 was decreased in HG-stimulated VSMCs and balloon-injured carotid arteries of diabetic rats, which was accompanied by increased expression of Ogt and Keap1 and decreased expression of Nrf2 and Ho-1. Up-regulation of miR-24 suppressed VSMC oxidative stress induced by HG in vitro, and miR-24 up-regulation promoted reendothelialization in balloon-injured diabetic rats. The underlying mechanism was related to the activation of the Nrf2/Ho-1 signaling pathway, which subsequently suppressed intracellular reactive oxidative species (ROS) production and malondialdehyde (MDA) and NADPH oxidase (Nox) activity, and to the restoration of Sod and Gsh-px activation.

CONCLUSIONS

The up-regulation of miR-24 significantly promoted endothelial repair after balloon injury through inhibition of oxidative stress by activating the Nrf2/Ho-1 signaling pathway.

Oxidative Stress in Peripheral Arterial Disease (PAD) Mechanism and Biomarkers

Hemodynamic dysfunction mainly characterizes pathophysiology of peripheral arterial disease (PAD) leading to chronic ischemia. Hemodynamic dysfunction is the origin of intermittent claudication (chronic PAD) or of critical limb ischemia (very severe PAD). Notably, it is well known that oxidative stress (OxS) plays a pathophysiological role in PAD. The higher production of reactive oxygen species (ROS) from OxS and reduced redox capability are two crucial players in initiating and progressing PAD. A number of biomarkers highlight OxS and monitor it in PAD. The present review summarizes data on OxS, on biomarkers available to mark OxS occurrence and to monitor on PAD progression, as well as to evaluate the effects treatments in PAD patients. In conclusion, by detailing OxS and its biomarkers, we hope to encourage more studies to focus on drugs which combat OxS and inflammation.

Cerebrovascular miRNAs correlate with the clearance of Aβ through perivascular route in younger 3xTg-AD mice

The "two-hit vascular hypothesis for Alzheimer's disease (AD)" and amyloid-β (Aβ) oligomer hypothesis suggest that impaired soluble Aβ oligomers clearance through the cerebral vasculature may be an initial step of the AD process. Soluble Aβ oligomers are driven into perivascular spaces from the brain parenchyma and toward peripheral blood flow. The underlying vascular-based mechanism, however, has not been defined. Given that microRNAs (miRNAs), emerging as novel modulators, are involved in numerous physiological and pathological processes, we hypothesized that cerebrovascular miRNAs may regulate the activities of brain blood vessels, which further affects the concentration of Aβ in the AD brain. In this study, perivascular Aβ deposits, higher vascular activation, increased pericyte coverage and up-regulated capillaries miRNAs at 6 months old (6 mo) were found to correlate with the lower Aβ levels of middle AD stage (9 mo) in 3xTg-AD (3xTg) mice. It is implicated that at the early stage of AD when intracellular Aβ appeared, higher expression of vessel-specific miRNAs, elevated pericyte coverage, and activated endothelium facilitate Aβ oligomer clearance through the perivascular route, resulting in a transient reduction of Aβ oligomers at 9 mo. Additionally, ghrelin-induced upregulation of capillary miRNAs and increased pericyte coverage attenuated Aβ burden at 9 mo, in further support of the relationship between vascular miRNAs and Aβ clearance. This work suggests a cerebral microvessel miRNA may boost endothelial highly activated phenotypes to promote elimination of Aβ oligomers through the perivascular drainage pathway and contribute to AD progression. The targeting of brain vessel-specific miRNAs may provide a new rationale for the development of innovative therapeutic strategies for AD treatment.

Sildenafil Reduces Neointimal Hyperplasia after Angioplasty and Inhibits Platelet Aggregation via Activation of cGMP-dependent Protein Kinase

Sildenafil is known to reduce cardiac hypertrophy through cGMP-dependent protein kinase (cGK) activation. Studies have demonstrated that cGK has a central switching role in modulating vascular smooth muscle cell (VSMC) phenotype in response to vascular injury. Here, we aimed to examine the effects of cGK activation by sildenafil on neointimal formation and platelet aggregation. After vascular injury, neointimal hyperplasia in rat carotid arteries was significantly reduced in the sildenafil-treated group. This effect of sildenafil was accompanied by the reduction of viability and migration of VSMCs. Further experiments showed that the increased cGK activity by sildenafil inhibited platelet-derived growth factor-induced phenotype change of VSMCs from a contractile form to a synthetic one. Conversely, the use of cGK inhibitor or gene transfer of dominant-negative cGK reversed the effects of sildenafil, increasing viability of VSMCs and neointimal formation. Interestingly, sildenafil significantly inhibited platelet aggregation induced by ADP or thrombin. This effect was reversed by cGK inhibitor, suggesting that sildenafil inhibits platelet aggregation via cGK pathway. This study demonstrated that sildenafil inhibited neointimal formation and platelet aggregation via cGK pathway. These results suggest that sildenafil could be a promising candidate for drug-eluting stents for the prevention of both restenosis and stent thrombosis.

Neoatherosclerosis after drug-eluting stent implantation: a novel clinical and therapeutic challenge

The recognition that obstructive disease of the epicardial coronary arteries, causing ischaemic heart disease, can be treated with a percutaneous coronary intervention (PCI) has been a major discovery in cardiology in the last 40 years contributing, in particular, to the reduction of mortality associated to acute myocardial infarction (AMI). However, even in the era of drug-eluting stent (DES) implantation, a sizable proportion of patients who undergo PCI may develop late or very late post-implantation complications, that occur in the form of restenosis, neoatherosclerosis, and/or in-stent thrombosis. Such complications are clinically relevant since they can cause AMI and negatively impact on the outcome. The underlying pathophysiological mechanisms are complex but related to inhibition of neointimal proliferation by DES that, on the hand, reduces the rate of in-stent restenosis, but, on the other hand, causes dysfunctional vessel healing, persistent inflammation, platelet activation, and adverse immunological responses. Multiple approaches have been developed or are under evaluation to target DES-related complications including pharmacotherapy, procedure-related imaging methods, novel stent designs, and drug-delivery methods. The aim of this review is to provide an update on the latest preclinical, translational, and clinical pharmacotherapeutic developments in this setting that target novel cellular mechanisms and pathways that might contribute to neoatherosclerosis. Due to the importance of secondary prevention in the reduction of DES-associated complications, this review also provides a short overview of pharmacological agents that are established or currently being investigated in this regard.

Prevalence of carotid artery stenosis in ischaemic heart disease patients in Bangladesh

Background:

Concurrent carotid artery stenosis and ischaemic heart disease rates are increasing day by day in Bangladesh. Moreover, carotid artery stenosis has been identified as a high-risk factor for postoperative ischaemic cerebral inconvenience following coronary artery bypass graft surgery.

Methods:

This observational cross-sectional study was performed to evaluate 200 study patients from July 2017 to June 2018. Patients with coronary artery disease scheduled for isolated elective coronary artery bypass graft surgery were included in the study, excluding those with coexisting valvular or congenital heart disease and emergency coronary artery bypass graft surgery.

Results:

About two-thirds of the study patients were 50–59 years old, with a mean age of 57.7 ± 3.06 years. Approximately 70% patients were male; the male:female ratio was 2.1:1. Most of the patients (74.5%) were Muslim. The majority of patients (59.0%) were overweight, and severe carotid artery stenosis was significantly higher in obese patients (p ⩽ 0.05). Furthermore, hypertension and diabetes mellitus were significantly associated with moderate to severe carotid artery stenosis (p ⩽ 0.05). Multi-vessel coronary artery disease was significantly associated with the severity of carotid artery stenosis. Bilateral carotid artery stenosis was significantly associated with the severity of carotid artery stenosis (p ⩽ 0.05).

Conclusion:

Routine duplex screening will identify significant carotid artery disease and will subsequently reduce the risk of perioperative stroke in ischaemic heart disease patients undergoing coronary artery bypass graft surgery.

Small GTPases and Their Role in Vascular Disease

Over eighty million people in the United States have cardiovascular disease that can affect the heart causing myocardial infarction; the carotid arteries causing stroke; and the lower extremities leading to amputation. The treatment for end-stage cardiovascular disease is surgical—either endovascular therapy with balloons and stents—or open reconstruction to reestablish blood flow. All interventions damage or destroy the protective inner lining of the blood vessel—the endothelium. An intact endothelium is essential to provide a protective; antithrombotic lining of a blood vessel. Currently; there are no agents used in the clinical setting that promote reendothelialization. This process requires migration of endothelial cells to the denuded vessel; proliferation of endothelial cells on the denuded vessel surface; and the reconstitution of the tight adherence junctions responsible for the formation of an impermeable surface. These processes are all regulated in part and are dependent on small GTPases. As important as the small GTPases are for reendothelialization, dysregulation of these molecules can result in various vascular pathologies including aneurysm formation, atherosclerosis, diabetes, angiogenesis, and hypertension. A better understanding of the role of small GTPases in endothelial cell migration is essential to the development for novel agents to treat vascular disease.

Nucleotide Modification Alters MicroRNA-Dependent Silencing of MicroRNA Switches

mRNA therapeutics hold great promise for the treatment of human diseases. While incorporating naturally occurring modified nucleotides during synthesis has greatly increased their potency and safety, challenges in selective expression have hindered clinical applications. MicroRNA (miRNA)-regulated in vitro-transcribed mRNAs, called miRNA switches, have been used to control the expression of exogenous mRNA in a cell-selective manner. However, the effect of nucleotide modifications on miRNA-dependent silencing has not been examined. Here we show that the incorporation of pseudouridine, N1-methylpseudourdine, or pseudouridine and 5-methylcytidine, which increases translation, tends to decrease the regulation of miRNA switches. Moreover, pseudouridine and 5-methylcytidine modification enables one miRNA target site at the 3′ UTR to be as effective as four target sites. We also demonstrate that the effects of pseudouridine, pseudouridine and 5-methylcytidine, and N1-methylpseudourdine modification are miRNA switch specific and do not correlate with the proportion of modified nucleotides in the miRNA target site. Furthermore, modified miRNA switches containing seed-complementary target sites are poorly regulated by miRNA. We also show that placing the miRNA target site in the 5′ UTR of the miRNA switch abolishes the effect of nucleotide modification on miRNA-dependent silencing. This work provides insights into the influence of nucleotide modifications on miRNA-dependent silencing and informs the design of optimal miRNA switches.

miRNA Regulation of the Hyperproliferative Phenotype of Vascular Smooth Muscle Cells in Diabetes

Harnessing the mechanisms underlying the exacerbated vascular remodeling in diabetes mellitus (DM) is pivotal to prevent the high toll of vascular diseases in patients with DM. miRNA regulates vascular smooth muscle cell (VSMC) phenotypic switch. However, miRNA modulation of the detrimental diabetic VSMC phenotype is underexplored. Streptozotocin-induced type 1 DM (T1DM) Wistar rats and type 2 DM (T2DM) Zucker rats underwent right carotid artery experimental angioplasty, and global miRNA/mRNA expression profiling was obtained by RNA sequencing (RNA-Seq). Two days after injury, a set of six miRNAs were found to be uniquely downregulated or upregulated in VSMCs both in T1DM and T2DM. Among these miRNAs, miR-29c and miR-204 were the most significantly misregulated in atherosclerotic plaques from patients with DM. miR-29c overexpression and miR-204 inhibition per se attenuated VSMC phenotypic switch in DM. Concomitant miR-29c overexpression and miR-204 inhibition fostered an additive reduction in VSMC proliferation. Epithelial membrane protein 2 (Emp2) and Caveolin-1 (Cav1) mRNAs were identified as direct targets of miR-29c and miR-204, respectively. Importantly, contemporary miR-29c overexpression and miR-204 inhibition in the injured artery robustly reduced arterial stenosis in DM rats. Thus, contemporaneous miR-29c activation and miR-204 inhibition in DM arterial tissues is necessary and sufficient to prevent the exaggerated VSMC growth upon injury.