The endothelium: influencing vascular smooth muscle in many ways

Abnormal expression of PRKAG2-AS1 in endothelial cells induced inflammation and apoptosis by reducing PRKAG2 expression

PRKAG2 is required for the maintenance of cellular energy balance. PRKAG2-AS1, a long non-coding RNA (lncRNA), was found within the promoter region of PRKAG2. Despite the extensive expression of PRKAG2-AS1 in endothelial cells, the precise function and mechanism of this gene in endothelial cells have yet to be elucidated. The localization of PRKAG2-AS1 was predominantly observed in the nucleus, as revealed using nuclear and cytoplasmic fractionation and fluorescence in situ hybridization. The manipulation of PRKAG2-AS1 by knockdown and overexpression within the nucleus significantly altered PRKAG2 expression in a cis-regulatory manner. The expression of PRKAG2-AS1 and its target genes, PRKAG2b and PRKAG2d, was down-regulated in endothelial cells subjected to oxLDL and Hcy-induced injury. This finding suggests that PRKAG2-AS1 may be involved in the mechanism behind endothelial injury. The suppression of PRKAG2-AS1 specifically in the nucleus led to an upregulation of inflammatory molecules such as cytokines, adhesion molecules, and chemokines in endothelial cells. Additionally, this nuclear suppression of PRKAG2-AS1 facilitated the adherence of THP1 cells to endothelial cells. We confirmed the role of nuclear knockdown PRKAG2-AS1 in the induction of apoptosis and inhibition of cell proliferation, migration, and lumen formation through flow cytometry, TUNEL test, CCK8 assay, and cell scratching. Finally, it was determined that PRKAG2-AS1 exerts direct control over the transcription of PRKAG2 by its binding to their promoters. In conclusion, downregulation of PRKAG2-AS1 suppressed the proliferation and migration, promoted inflammation and apoptosis of endothelial cells, and thus contributed to the development of atherosclerosis resulting from endothelial cell injury.

Aortic Cellular Heterogeneity in Health and Disease: Novel Insights Into Aortic Diseases From Single-Cell RNA Transcriptomic Data Sets

Aortic diseases such as atherosclerosis, aortic aneurysms, and aortic stiffening are significant complications that can have significant impact on end-stage cardiovascular disease. With limited pharmacological therapeutic strategies that target the structural changes in the aorta, surgical intervention remains the only option for some patients with these diseases. Although there have been significant contributions to our understanding of the cellular architecture of the diseased aorta, particularly in the context of atherosclerosis, furthering our insight into the cellular drivers of disease is required. The major cell types of the aorta are well defined; however, the advent of single-cell RNA sequencing provides unrivaled insights into the cellular heterogeneity of each aortic cell type and the inferred biological processes associated with each cell in health and disease. This review discusses previous concepts that have now been enhanced with recent advances made by single-cell RNA sequencing with a focus on aortic cellular heterogeneity.

Vasorelaxant effects of ellagitannins isolated from Cuphea carthagenensis

Cuphea carthagenensis (Jacq.) J. F. Macbr. is a popular plant in Brazilian folk medicine owing to its hypotensive and central nervous system depressant effects. This study aimed to validate the hypotensive effect of the plant's aqueous extract (AE) in rats and examine the vascular actions of three hydrolyzable tannins, oenothein B, woodfordin C, and eucalbanin B, isolated from AE. Systolic blood pressure in unanesthetized rats was determined using the non-invasive tail-cuff method. Oral treatment of normotensive rats with 0.5 and 1.0 g/kg/day AE induced a dose-related hypotensive effect after 1 week. In rat aortic rings pre-contracted with noradrenaline, all ellagitannins (20 - 180 µM) induced a concentration-related vasorelaxation. This effect was blocked by either removing the endothelium or pre-incubating with NG-nitro-l-arginine methyl ester (10 µM), an inhibitor of nitric oxide (NO) synthase. In KCl-depolarized rat portal vein preparations, the investigated compounds did not affect significantly the maximal contractile responses and pD2 values of the concentration-response curves to CaCl2. Our results demonstrated the hypotensive effect of C. carthagenensis AE in unanesthetized rats. All isolated ellagitannins induced vasorelaxation in vitro via activating NO synthesis/NO release from endothelial cells, without altering the Ca2+ influx in vascular smooth muscle preparations. Considering the low oral bioavailability of ellagitannins, the determined in vitro actions of these compounds are unlikely to account for the hypotensive effect of AE in vivo. It remains to be determined the role of the bioactive ellagitannin-derived metabolites in the hypotensive effect observed after oral treatment of unanesthetized rats with the plant extract.

Functional regeneration at the blood-biomaterial interface

The use of cardiovascular implants is commonplace in clinical practice. However, reproducing the key bioactive and adaptive properties of native cardiovascular tissues with an artificial replacement is highly challenging. Exciting new treatment strategies are under development to regenerate (parts of) cardiovascular tissues directly in situ using immunomodulatory biomaterials. Direct exposure to the bloodstream and hemodynamic loads is a particular challenge, given the risk of thrombosis and adverse remodeling that it brings. However, the blood is also a source of (immune) cells and proteins that dominantly contribute to functional tissue regeneration. This review explores the potential of the blood as a source for the complete or partial in situ regeneration of cardiovascular tissues, with a particular focus on the endothelium, being the natural blood-tissue barrier. We pinpoint the current scientific challenges to enable rational engineering and testing of blood-contacting implants to leverage the regenerative potential of the blood.

Copaiba oil improves pulmonary nitric oxide bioavailability in monocrotaline-treated rats

Oxidative stress is involved in increased pulmonary vascular resistance (PVR) and right ventricular (RV) hypertrophy, characteristics of pulmonary arterial hypertension (PAH). Copaiba oil, an antioxidant compound, could attenuate PAH damage. This study's aim was to determine the effects of copaiba oil on lung oxidative stress, PVR, and mean pulmonary arterial pressure (mPAP) in the monocrotaline (MCT) model of PAH. Male Wistar rats (170 g, n = 7/group) were divided into four groups: control, MCT, copaiba oil, and MCT + copaiba oil (MCT-O). PAH was induced by MCT (60 mg/kg i.p.) and, after 1 week, the treatment with copaiba oil (400 mg/kg/day gavage) was started for 14 days. Echocardiographic and hemodynamic measurements were performed. RV was collected for morphometric evaluations and lungs and the pulmonary artery were used for biochemical analysis. Copaiba oil significantly reduced RV hypertrophy, PVR, mPAP, and antioxidant enzyme activities in the MCT-O group. Moreover, increased nitric oxide synthase and decreased NADPH oxidase activities were observed in the MCT-O group. In conclusion, copaiba oil was able to improve the balance between nitric oxide and reactive oxygen species in lungs and the pulmonary artery and to reduce PVR, which could explain a decrease in RV hypertrophy in this PAH model.

Cardiomodulatory and Antioxidative Potentials of Almond-Citrus Peel Fortified Shortbread in High Fat Diet/L-NAME-Induced Hyperlipidemic-Hypertensive Rats

In folk medicine, the almond nut (Terminalia catappa) and orange peel (Citrus sinensis) are cost-effective sources of nutraceutical utilized in the treatment of degenerative diseases. Hyperlipidemia and hypertension are two pathological conditions implicated in cardiovascular disorders. This study sought to evaluate the cardiomodulatory effect of almond-citrus peel fortified shortbread in hyperlipidemic-hypertensive rats induced by high fat diet and Nω-nitro-l-arginine methyl ester. The experimental animals were divided into eight groups. The experimental rats were fed with shortbread supplemented with almond and citrus peel at varying inclusions of 0.2% citrus, 50% almond, and almond (50%)- citrus (0.2%) for 21 days. The mean arterial blood pressure (MABP), systolic blood pressure (SBP), and lipid profile of the experimental rats were measured. Thereafter, the activities of angiotensin-1-converting enzyme (ACE), arginase, malondialdehyde (MDA), phosphodiesterase-5, nitric oxide (NO), and antioxidant indices were evaluated. The result showed significant elevation in SBP, MABP, blood cholesterol, triglyceride, ACE, arginase, activities, and MDA levels in the heart tissue of the untreated rats. In contrast, the antioxidant status and NO level were significantly decreased in the untreated groups. Remarkably, the treatment with almond-citrus peel fortified shortbread and the individual effect of almond (50%) and citrus peel (0.2%) all reversed these trends in the hyperlipidemic-hypertensive rats. Intriguingly, the blend of almond (50%)-citrus peel (0.2%) fortified shortbread showed the best antioxidative and cardioprotective effect. The results suggest that almond and citrus peel offer potentials as therapeutic agent in the prevention and management of hyperlipidemia and hypertension.

Pathological mechanisms of cigarette smoking, dietary, and sedentary lifestyle risks in vascular dysfunction: mitochondria as a common target of risk factors

In the past century, the lifespan of the human population has dramatically increased to the 80 s, but it is hindered by a limited health span to the 60 s due to an epidemic increase in the cardiovascular disease which is a main cause of morbidity and mortality. We cannot underestimate the progress in understanding the major cardiovascular risk factors which include cigarette smoking, dietary, and sedentary lifestyle risks. Despite their clinical significance, these modifiable risk factors are still the major contributors to cardiovascular disease. It is, therefore, important to understand the specific molecular mechanisms behind their pathological effects to develop new therapies to improve the treatment of cardiovascular disease. In recent years, our group and others have made a progress in understanding how these risk factors can promote endothelial dysfunction, smooth muscle dysregulation, vascular inflammation, hypertension, lung, and heart diseases. These factors, despite differences in their nature, lead to stereotypical alterations in vascular metabolism and function. Interestingly, cigarette smoking has a tremendous impact on a very distant site from the initial epithelial exposure, namely circulation and vascular cells mediated by a variety of stable cigarette smoke components which promote vascular oxidative stress and alter vascular metabolism and function. Similarly, dietary and sedentary lifestyle risks facilitate vascular cell metabolic reprogramming promoting vascular oxidative stress and dysfunction. Mitochondria are critical in cellular metabolism, and in this work, we discuss a new concept that mitochondria are a common pathobiological target for these risk factors, and mitochondria-targeted treatments may have a therapeutic effect in the patients with cardiovascular disease.

Melatonin and TGF-β-Mediated Release of Extracellular Vesicles

The immune system, unlike other systems, must be flexible and able to "adapt" to fully cope with lurking dangers. The transition from intracorporeal balance to homeostasis disruption is associated with activation of inflammatory signaling pathways, which causes modulation of the immunology response. Chemotactic cytokines, signaling molecules, and extracellular vesicles act as critical mediators of inflammation and participate in intercellular communication, conditioning the immune system's proper response. Among the well-known cytokines allowing for the development and proper functioning of the immune system by mediating cell survival and cell-death-inducing signaling, the tumor necrosis factor α (TNF-α) and transforming growth factor β (TGF-β) are noteworthy. The high bloodstream concentration of those pleiotropic cytokines can be characterized by anti- and pro-inflammatory activity, considering the powerful anti-inflammatory and anti-oxidative stress capabilities of TGF-β known from the literature. Together with the chemokines, the immune system response is also influenced by biologically active chemicals, such as melatonin. The enhanced cellular communication shows the relationship between the TGF-β signaling pathway and the extracellular vesicles (EVs) secreted under the influence of melatonin. This review outlines the findings on melatonin activity on TGF-β-dependent inflammatory response regulation in cell-to-cell communication leading to secretion of the different EV populations.

Capsaicin: A Potential Treatment to Improve Cerebrovascular Function and Cognition in Obesity and Ageing

Impaired cognition is the primary symptom of dementia, which can lead to functional disability and reduced quality of life among an increasingly ageing population. Ageing is associated with increased oxidative stress, chronic low-grade systemic inflammation, and endothelial dysfunction, which reduces cerebrovascular function leading to cognitive decline. Chronic low-grade systemic inflammatory conditions, such as obesity, exacerbate this decline beyond normal ageing and predispose individuals to neurodegenerative diseases, such as dementia. Capsaicin, the major pungent molecule of chilli, has recently demonstrated improvements in cognition in animal models via activation of the transient receptor potential vanilloid channel 1 (TRPV1). Capsaicin-induced TRPV1 activation reduces adiposity, chronic low-grade systemic inflammation, and oxidative stress, as well as improves endothelial function, all of which are associated with cerebrovascular function and cognition. This review examines the current literature on capsaicin and Capsimax, a capsaicin supplement associated with reduced gastrointestinal irritation compared to capsaicin. Acute and chronic capsaicin treatment can improve cognition in animals. However, studies adequately assessing the effects of capsaicin on cerebrovascular function, and cognition in humans do not exist. Capsimax may be a potentially safe therapeutic intervention for future clinical trials testing the effects of capsaicin on cerebrovascular function and cognition.

Microangiopathy in Rheumatic Diseases

Capillaries are part of the microcirculation, which consists of arterioles, capillaries, and venules and are the connecting link between the arterial and venous blood circulation [...].

Morphological and Functional Remodeling of Vascular Endothelium in Cardiovascular Diseases

The vascular endothelium plays a vital role during embryogenesis and aging and is a cell monolayer that lines the blood vessels. The immune system recognizes the endothelium as its own. Therefore, an abnormality of the endothelium exposes the tissues to the immune system and provokes inflammation and vascular diseases such as atherosclerosis. Its secretory role allows it to release vasoconstrictors and vasorelaxants as well as cardio-modulatory factors that maintain the proper functioning of the circulatory system. The sealing of the monolayer provided by adhesion molecules plays an important role in cardiovascular physiology and pathology.

Effects of Salvia miltiorrhiza active compounds on placenta-mediated pregnancy complications

Placenta-mediated pregnancy complications (PMPCs), including preeclampsia (PE), fetal growth restriction (FGR), and recurrent spontaneous abortion (RSA), occur in approximately 5% of pregnancies and are caused by abnormal placenta development. The development of effective therapies for PMPCs is still challenging due to the complicated pathogenesis, such as disrupted vascular homeostasis and subsequent abnormal placentation. Synthetic drugs have been recommended for treating PMPCs; however, they tend to cause adverse reactions in the mother and fetus. Salvia miltiorrhiza (S. miltiorrhiza) has potential effects on PMPCs owing to its advantages in treating cardiovascular disorders. S. miltiorrhiza and its active compounds could attenuate the symptoms of PMPCs through anticoagulation, vasodilation, antioxidation, and endothelial protection. Thus, in this review, we summarize the literature and provide comprehensive insights on S. miltiorrhiza and its phytochemical constituents, pharmacological activities, and on PMPCs, which would be valuable to explore promising drugs.

Design, synthesis and biological evaluation of dehydroabietic acid derivative as potent vasodilatory agents

Using dehydroabietic acid as the lead compound for structural modification, 25 dehydroabietic acid derivatives were synthesized. Among them, compound D1 not only showed the strongest relaxation effect on the aortic vascular ring in vitro (Emax = 99.5 ± 2.1%, EC50 = 3.03 ± 0.96 µM), but also significantly reduced systolic and diastolic blood pressure in rats at a dose of 2.0 mg/kg in vivo. Next, the vascular protective effect of the best active D1 and its molecular mechanism were further investigated by HUVECs. The results showed that D1 induced endothelium-dependent diastole in the rat thoracic aorta in a concentration-dependent manner. Endothelium removal or aortic ring pretreatment with NG-nitro-l-arginine methylester (l-NAME), 1H-[1,2,4]-oxadiazolo-[4,3-a]-quinoxalin-1-one (ODQ), and tetraethylammonium (TEA) significantly inhibited D1-induced relaxation. In addition, wortmannin, KT5823, triciribine, diltiazem, BaCl2, 4-aminopyridine, indomethacin, propranolol, and atropine attenuated D1-induced vasorelaxation. D1 increased the phosphorylation of eNOS in HUVECs Furthermore, D1 attenuated the expression of TNF-α-induced cell adhesion molecules such as ICAM-1 and VCAM-1. However, this effect was attenuated by the eNOS inhibitors l-NAME and asymmetric dimethylarginine (ADMA). The findings suggest that D1-induced vasorelaxation through the PI3K/Akt/eNOS/NO/cGMP/PKG pathway by activating the KCa, Kir and KV channels or muscarinic and β-adrenergic receptors, and inhibiting the l-type Ca2+ channels, which is closely related to the hypotensive action of the agent. Furthermore, D1 exhibits an inhibitory effect on vascular inflammation, which is associated with the observed vascular protective effects.

Tissue Reactions and Mechanism in Cardiovascular Diseases Induced by Radiation

The long-term survival rate of cancer patients has been increasing as a result of advances in treatments and precise medical management. The evidence has accumulated that the incidence and mortality of non-cancer diseases have increased along with the increase in survival time and long-term survival rate of cancer patients after radiotherapy. The risk of cardiovascular disease as a radiation late effect of tissue damage reactions is becoming a critical challenge and attracts great concern. Epidemiological research and clinical trials have clearly shown the close association between the development of cardiovascular disease in long-term cancer survivors and radiation exposure. Experimental biological data also strongly supports the above statement. Cardiovascular diseases can occur decades post-irradiation, and from initiation and development to illness, there is a complicated process, including direct and indirect damage of endothelial cells by radiation, acute vasculitis with neutrophil invasion, endothelial dysfunction, altered permeability, tissue reactions, capillary-like network loss, and activation of coagulator mechanisms, fibrosis, and atherosclerosis. We summarize the most recent literature on the tissue reactions and mechanisms that contribute to the development of radiation-induced cardiovascular diseases (RICVD) and provide biological knowledge for building preventative strategies.

Skin Microhemodynamics and Mechanisms of Its Regulation in Type 2 Diabetes Mellitus

The review presents modern ideas about peripheral microhemodynamics, approaches to the ana-lysis of skin blood flow oscillations and their diagnostic significance. Disorders of skin microhemodynamics in type 2 diabetes mellitus (DM) and the possibility of their interpretation from the standpoint of external and internal interactions between systems of skin blood flow regulation, based on a comparison of couplings in normal and pathological conditions, including models of pathologies on animals, are considered. The factors and mechanisms of vasomotor regulation, among them receptors and signaling events in endothelial and smooth muscle cells considered as models of microvessels are discussed. Attention was drawn to the disturbance of Ca2+-dependent regulation of coupling between vascular cells and NO-dependent regulation of vasodilation in diabetes mellitus. The main mechanisms of insulin resistance in type 2 DM are considered to be a defect in the number of insulin receptors and impaired signal transduction from the receptor to phosphatidylinositol-3-kinase and downstream targets. Reactive oxygen species plays an important role in vascular dysfunction in hyperglycemia. It is assumed that the considered molecular and cellular mechanisms of microhemodynamics regulation are involved in the formation of skin blood flow oscillations. Parameters of skin blood microcirculation can be used as diagnostic and prognostic markers for assessing the state of the body.

The mechanisms of glycolipid metabolism disorder on vascular injury in type 2 diabetes

Patients with diabetes have severe vascular complications, such as diabetic nephropathy, diabetic retinopathy, cardiovascular disease, and neuropathy. Devastating vascular complications lead to increased mortality, blindness, kidney failure, and decreased overall quality of life in people with type 2 diabetes (T2D). Glycolipid metabolism disorder plays a vital role in the vascular complications of T2D. However, the specific mechanism of action remains to be elucidated. In T2D patients, vascular damage begins to develop before insulin resistance and clinical diagnosis. Endothelial dysregulation is a significant cause of vascular complications and the early event of vascular injury. Hyperglycemia and hyperlipidemia can trigger inflammation and oxidative stress, which impair endothelial function. Furthermore, during the pathogenesis of T2D, epigenetic modifications are aberrant and activate various biological processes, resulting in endothelial dysregulation. In the present review, we provide an overview and discussion of the roles of hyperglycemia- and hyperlipidemia-induced endothelial dysfunction, inflammatory response, oxidative stress, and epigenetic modification in the pathogenesis of T2D. Understanding the connections of glucotoxicity and lipotoxicity with vascular injury may reveal a novel potential therapeutic target for diabetic vascular complications.

Xanthotoxin (8-methoxypsoralen): A review of its chemistry, pharmacology, pharmacokinetics, and toxicity

Xanthotoxin (XAT) is a natural furanocoumarins, a bioactive psoralen isolated from the fruit of the Rutaceae plant Pepper, which has received increasing attention in recent years due to its wide source and low cost. By collecting and compiling literature on XAT, the results show that XAT exhibits significant activity in the treatment of various diseases, including neuroprotection, skin repair, osteoprotection, organ protection, anticancer, antiinflammatory, antioxidative stress and antibacterial. In this paper, we review the pharmacological activity and potential molecular mechanisms of XAT for the treatment of related diseases. The data suggest that XAT can mechanistically induce ROS production and promote apoptosis through mitochondrial or endoplasmic reticulum pathways, regulate NF-κB, MAPK, JAK/STAT, Nrf2/HO-1, MAPK, AKT/mTOR, and ERK1/2 signaling pathways to exert pharmacological effects. In addition, the pharmacokinetics properties and toxicity of XAT are discussed in this paper, further elucidating the relationship between structure and efficacy. It is worth noting that data from clinical studies of XAT are still scarce, limiting the use of XAT in the clinic, and in the future, more in-depth studies are needed to determine the clinical efficacy of XAT.

Tongnao Decoction (TND) Alleviated Atherosclerosis by Playing Lowering Lipid, Anti-Inflammatory, and Antioxidant Roles

Background

Tongnao decoction (TND) has been extensively prescribed for the treatment of stroke. However, little is known about the role of TND in the progression of carotid atherosclerosis.

Methods

A mouse carotid atherosclerosis model was established with a silastic collar placed around the right common carotid artery and fed on Western diet for 12 weeks. The treatment group was given a gavage of TND at a dose of 1 mg/kg/d. The atherosclerotic lesion size and the compositions were observed using Oil red O staining and immunofluorescent staining. Enzyme-linked immunosorbent assay (ELISA) was used to evaluate the levels of lipid profiles, oxidative stress, and inflammatory factors. Human aortic endothelial cells (HAoECs) were treated with oxLDL with or without TND for in vitro experiments.

Results

TND treatment significantly suppressed the progression of atherosclerosis, as characterized with a smaller lesion size, less percentage of vascular smooth muscle cell proliferation, endothelial cell apoptosis, and macrophage infiltration. In addition, TND decreased the levels of lipid profiles, oxidative stress, and inflammatory factors in atherosclerosis. In vitro results showed that TND inhibited the apoptosis of endothelial cells via activating ERK and AKT pathway.

Conclusions

Our study demonstrated that TND significantly protected from atherosclerosis via promoting endothelial cell survival and alleviating oxidative stress and inflammatory response, which may have become a treatment in atherosclerotic diseases.

A Detailed Study to Discover the Trade between Left Atrial Blood Flow, Expression of Calcium-Activated Potassium Channels and Valvular Atrial Fibrillation

Background: The present study aimed to explore the correlation between calcium-activated potassium channels, left atrial flow field mechanics, valvular atrial fibrillation (VAF), and thrombosis. The process of transforming mechanical signals into biological signals has been revealed, which offers new insights into the study of VAF. Methods: Computational fluid dynamics simulations use numeric analysis and algorithms to compute flow parameters, including turbulent shear stress (TSS) and wall pressure in the left atrium (LA). Real-time PCR and western blotting were used to detect the mRNA and protein expression of IKCa2.3/3.1, ATK1, and P300 in the left atrial tissue of 90 patients. Results: In the valvular disease group, the TSS and wall ressure in the LA increased, the wall pressure increased in turn in all disease groups, mainly near the mitral valve and the posterior portion of the LA, the increase in TSS was the most significant in each group near the mitral valve, and the middle and lower part of the back of the LA and the mRNA expression and protein expression levels of IKCa2.3/3.1, AKT1, and P300 increased (p < 0.05) (n = 15). The present study was preliminarily conducted to elucidate whether there might be a certain correlation between IKCa2.3 and LA hemodynamic changes. Conclusions: The TSS and wall pressure changes in the LA are correlated with the upregulation of mRNA and protein expression of IKCa2.3/3.1, AKT1, and P300.

The Role of Amino Acids in Endothelial Biology and Function

The vascular endothelium acts as an important component of the vascular system. It is a barrier between the blood and vessel wall. It plays an important role in regulating blood vessel tone, permeability, angiogenesis, and platelet functions. Several studies have shown that amino acids (AA) are key regulators in maintaining vascular homeostasis by modulating endothelial cell (EC) proliferation, migration, survival, and function. This review summarizes the metabolic and signaling pathways of AAs in ECs and discusses the importance of AA homeostasis in the functioning of ECs and vascular homeostasis. It also discusses the challenges in understanding the role of AA in the development of cardiovascular pathophysiology and possible directions for future research.

Oxidative Stress, Vascular Endothelium, and the Pathology of Neurodegeneration in Retina

Oxidative stress (OS) is an imbalance between free radicals/ROS and antioxidants, which evokes a biological response and is an important risk factor for diseases, in both the cardiovascular system and central nervous system (CNS). The underlying mechanisms driving pathophysiological complications that arise from OS remain largely unclear. The vascular endothelium is emerging as a primary target of excessive glucocorticoid and catecholamine action. Endothelial dysfunction (ED) has been implicated to play a crucial role in the development of neurodegeneration in the CNS. The retina is known as an extension of the CNS. Stress and endothelium dysfunction are suspected to be interlinked and associated with neurodegenerative diseases in the retina as well. In this narrative review, we explore the role of OS-led ED in the retina by focusing on mechanistic links between OS and ED, ED in the pathophysiology of different retinal neurodegenerative conditions, and how a better understanding of the role of endothelial function could lead to new therapeutic approaches for neurodegenerative diseases in the retina.

The Biofabrication of Diseased Artery In Vitro Models

As the leading causes of global death, cardiovascular diseases are generally initiated by artery-related disorders such as atherosclerosis, thrombosis, and aneurysm. Although clinical treatments have been developed to rescue patients suffering from artery-related disorders, the underlying pathologies of these arterial abnormalities are not fully understood. Biofabrication techniques pave the way to constructing diseased artery in vitro models using human vascular cells, biomaterials, and biomolecules, which are capable of recapitulating arterial pathophysiology with superior performance compared with conventional planar cell culture and experimental animal models. This review discusses the critical elements in the arterial microenvironment which are important considerations for recreating biomimetic human arteries with the desired disorders in vitro. Afterward, conventionally biofabricated platforms for the investigation of arterial diseases are summarized, along with their merits and shortcomings, followed by a comprehensive review of advanced biofabrication techniques and the progress of their applications in establishing diseased artery models.

Therapeutic approach for digestive system cancers and potential implications of exercise under hypoxia condition: what little is known? a narrative review

BACKGROUND

Cancer, like other chronic pathologies, is associated with the presence of hypoxic regions due to the uncontrolled cell growth. Under this pathological hypoxic condition, various molecular signaling pathways are activated to ensure cell survival, such as those that govern angiogenesis, erythropoiesis, among others. These molecular processes are very similar to the physiological response caused by exposure to altitude (natural hypobaric systemic hypoxia), the use of artificial hypoxia devices (systemic normobaric simulated hypoxia) or the delivery of vascular occlusion to the extremities (also called local hypoxia by the blood flow restriction technique). "Tumor hypoxia" has gained further clinical importance due to its crucial role in both tumor progression and resistance to treatment. However, the ability to manipulate this pathway through physical exercise and systemic hypoxia-mediated signaling pathways could offer an important range of therapeutic opportunities that should be further investigated.

METHODS

This review is focused on the potential implications of systemic hypoxia combined with exercise in digestive system neoplasms prognosis. Articles included in the review were retrieved by searching among the three main scientific databases: PubMed, Scopus, and Embase.

FINDINGS

The findings of this review suggest that exercise performed under systemic hypoxic conditions could have a positive impact in prognosis and quality of life of the population with digestive system cancers.

CONCLUSIONS

Further studies are needed to consider this paradigm as a new potential intervention in digestive oncological population.

Effects of Remote Ischaemic Preconditioning on the Internal Thoracic Artery Nitric Oxide Synthase Isoforms in Patients Undergoing Coronary Artery Bypass Grafting

Remote ischaemic preconditioning (RIPC) is a medical procedure that consists of repeated brief periods of transient ischaemia and reperfusion of distant organs (limbs) with the ability to provide internal organ protection from ischaemia. Even though RIPC has been successfully applied in patients with myocardial infarction during coronary revascularization (surgery/percutaneous angioplasty), the underlying molecular mechanisms are yet to be clarified. Thus, our study aimed to determine the role of nitric oxide synthase (NOS) isoforms in RIPC-induced protection (3 × 5 min of forearm ischaemia with 5 min of reperfusion) of arterial graft in patients undergoing urgent coronary artery bypass grafting (CABG). We examined RIPC effects on specific expression and immunolocalization of three NOS isoforms — endothelial (eNOS), inducible (iNOS) and neuronal (nNOS) in patients’ internal thoracic artery (ITA) used as a graft. We found that the application of RIPC protocol leads to an increased protein expression of eNOS, which was further confirmed with strong eNOS immunopositivity, especially in the endothelium and smooth muscle cells of ITA. The same analysis of two other NOS isoforms, iNOS and nNOS, showed no significant differences between patients undergoing CABG with or without RIPC. Our results demonstrate RIPC-induced upregulation of eNOS in human ITA, pointing to its significance in achieving protective phenotype on a systemic level with important implications for graft patency.

Irisin in atherosclerosis

Irisin, a novel exercise-induced myokine, has been shown to play important roles in increasing white adipose tissue browning, regulating energy metabolism and improving insulin resistance. Growing evidence suggests a direct role for irisin in preventing atherosclerosis (AS) by inhibiting oxidative stress, improving dyslipidemia, facilitating anti-inflammation, reducing cellular damage and recovering endothelial function. In addition, some studies have noted that serum irisin levels play an essential role in cardiovascular diseases (CVDs) risk prediction, highlighting that irisin has the potential to be a useful predictive marker and therapeutic target of AS, especially in monitoring therapeutic efficacy. This review summarizes the understanding of irisin-mediated regulation in essential biological pathways and functions in atherosclerosis and prompts further exploitation of the biological properties of irisin in the pathogenesis of atherosclerosis.

Sex Differences in the Vasodilation Mediated by G Protein-Coupled Estrogen Receptor (GPER) in Hypertensive Rats

Background

The protective effect of estrogen on the vasculature cannot be explained only by its action through the receptors ERα and ERβ. G protein-coupled estrogen receptors (GPER)-which are widely distributed throughout the cardiovascular system-may also be involved in this response. However, little is known about GPER actions in hypertension. Therefore, in this study we evaluated the vascular response mediated by GPER using a specific agonist, G-1, in spontaneously hypertensive rats (SHR). We hypothesized that G-1 would induce a relaxing response in resistance mesenteric arteries from SHR of both sexes.

Methods

G-1 concentration-response curves (1 nM-10 μM) were performed in mesenteric arteries from SHR of both sexes (10-12-weeks-old, weighing 180-250 g). The effects of G-1 were evaluated before and after endothelial removal and incubation for 30 min with the inhibitors L-NAME (300 μM) and indomethacin (10 μM) alone or combined with clotrimazole (0.75 μM) or catalase (1,000 units/mL). GPER immunolocalization was also investigated, and vascular hydrogen peroxide (H₂O₂) and ROS were evaluated using dichlorofluorescein (DCF) and dihydroethidium (DHE) staining, respectively.

Results

GPER activation promoted a similar relaxing response in resistance mesenteric arteries of female and male hypertensive rats, but with the participation of different endothelial mediators. Males appear to be more dependent on the NO pathway, followed by the H₂O₂ pathway, and females on the endothelium and H₂O₂ pathway.

Conclusion

These findings show that the GPER agonist G-1 can induce a relaxing response in mesenteric arteries from hypertensive rats of both sexes in a similar way, albeit with differential participation of endothelial mediators. These results contribute to the understanding of GPER activation on resistance mesenteric arteries in essential hypertension.

Short-term high fat diet alters genes associated with metabolic and vascular dysfunction during adolescence in rats: a pilot study

Background

Diet-induced metabolic dysfunction precedes multiple disease states including diabetes, heart disease, and vascular dysfunction. The critical role of the vasculature in disease progression is established, yet the details of how gene expression changes in early cardiovascular disease remain an enigma. The objective of the current pilot project was to evaluate whether a quantitative assessment of gene expression within the aorta of six-week old healthy male Sprague-Dawley rats compared to those exhibiting symptoms of metabolic dysfunction could reveal potential mediators of vascular dysfunction.

Methods

RNA was extracted from the aorta of eight rats from a larger experiment; four animals fed a high-fat diet (HFD) known to induce symptoms of metabolic dysfunction (hypertension, increased adiposity, fasting hyperglycemia) and four age-matched healthy animals fed a standard chow diet (CHOW). The bioinformatic workflow included Gene Ontology (GO) biological process enrichment and network analyses.

Results

The resulting network contained genes relevant to physiological processes including fat and protein metabolism, oxygen transport, hormone regulation, vascular regulation, thermoregulation, and circadian rhythm. The majority of differentially regulated genes were downregulated, including several associated with circadian clock function. In contrast, leptin and 3-hydroxy-3-methylglutaryl-CoA synthase 2 (Hmgcs2) were notably upregulated. Leptin is involved in several major energy balance signaling pathways and Hmgcs2 is a mitochondrial enzyme that catalyzes the first reaction of ketogenesis.

Conclusion

Together, these data describe changes in gene expression within the aortic wall of HFD rats with early metabolic dysfunction and highlight potential pathways and signaling intermediates that may impact the development of early vascular dysfunction.

Cellular Crosstalk between Endothelial and Smooth Muscle Cells in Vascular Wall Remodeling

Pathological vascular wall remodeling refers to the structural and functional changes of the vessel wall that occur in response to injury that eventually leads to cardiovascular disease (CVD). Vessel wall are composed of two major primary cells types, endothelial cells (EC) and vascular smooth muscle cells (VSMCs). The physiological communications between these two cell types (EC–VSMCs) are crucial in the development of the vasculature and in the homeostasis of mature vessels. Moreover, aberrant EC–VSMCs communication has been associated to the promotor of various disease states including vascular wall remodeling. Paracrine regulations by bioactive molecules, communication via direct contact (junctions) or information transfer via extracellular vesicles or extracellular matrix are main crosstalk mechanisms. Identification of the nature of this EC–VSMCs crosstalk may offer strategies to develop new insights for prevention and treatment of disease that curse with vascular remodeling. Here, we will review the molecular mechanisms underlying the interplay between EC and VSMCs. Additionally, we highlight the potential applicable methodologies of the co-culture systems to identify cellular and molecular mechanisms involved in pathological vascular wall remodeling, opening questions about the future research directions.

Endothelial Dysfunction, Inflammation and Coronary Artery Disease: Potential Biomarkers and Promising Therapeutical Approaches

Coronary artery disease (CAD) and its complications are the leading cause of death worldwide. Inflammatory activation and dysfunction of the endothelium are key events in the development and pathophysiology of atherosclerosis and are associated with an elevated risk of cardiovascular events. There is great interest to further understand the pathophysiologic mechanisms underlying endothelial dysfunction and atherosclerosis progression, and to identify novel biomarkers and therapeutic strategies to prevent endothelial dysfunction, atherosclerosis and to reduce the risk of developing CAD and its complications. The use of liquid biopsies and new molecular biology techniques have allowed the identification of a growing list of molecular and cellular markers of endothelial dysfunction, which have provided insight on the molecular basis of atherosclerosis and are potential biomarkers and therapeutic targets for the prevention and or treatment of atherosclerosis and CAD. This review describes recent information on normal vascular endothelium function, as well as traditional and novel potential biomarkers of endothelial dysfunction and inflammation, and pharmacological and non-pharmacological therapeutic strategies aimed to protect the endothelium or reverse endothelial damage, as a preventive treatment for CAD and related complications.

Eicosanoid blood vessel regulation in physiological and pathological states

Arachidonic acid can be metabolized in blood vessels by three primary enzymatic pathways; cyclooxygenase (COX), lipoxygenase (LO), and cytochrome P450 (CYP). These eicosanoid metabolites can influence endothelial and vascular smooth muscle cell function. COX metabolites can cause endothelium-dependent dilation or constriction. Prostaglandin I2 (PGI2) and thromboxane (TXA2) act on their respective receptors exerting opposing actions with regard to vascular tone and platelet aggregation. LO metabolites also influence vascular tone. The 12-LO metabolite 12S-hydroxyeicosatrienoic acid (12S-HETE) is a vasoconstrictor whereas the 15-LO metabolite 11,12,15-trihydroxyeicosatrienoic acid (11,12,15-THETA) is an endothelial-dependent hyperpolarizing factor (EDHF). CYP enzymes produce two types of eicosanoid products: EDHF vasodilator epoxyeicosatrienoic acids (EETs) and the vasoconstrictor 20-HETE. The less-studied cross-metabolites generated from arachidonic acid metabolism by multiple pathways can also impact vascular function. Likewise, COX, LO, and CYP vascular eicosanoids interact with paracrine and hormonal factors such as the renin-angiotensin system and endothelin-1 (ET-1) to maintain vascular homeostasis. Imbalances in endothelial and vascular smooth muscle cell COX, LO, and CYP metabolites in metabolic and cardiovascular diseases result in vascular dysfunction. Restoring the vascular balance of eicosanoids by genetic or pharmacological means can improve vascular function in metabolic and cardiovascular diseases. Nevertheless, future research is necessary to achieve a more complete understanding of how COX, LO, CYP, and cross-metabolites regulate vascular function in physiological and pathological states.

Resistance mesenteric arteries display hypercontractility in the resolution time of Strongyloides venezuelensis infection

The blood flow in the mesenteric region is crucial for nutrient absorption and immune response in the gastrointestinal tract. The presence of nematodes or their excreted/secreted products seems to provoke vascular dysfunction. However, it is unclear whether and how the intestinal nematodes with habitat in the intestinal niche could affect the mesenteric vascular resistance. In this study, male Wistar rats were infected with 2000 larvae of S. venezuelensis, and experiments were conducted at 0 (non-infected control), 10 or 30 days post-infection (DPI). Eggs were counted in rats' feces and adult worms recovered from the small intestine. Second- or third-order mesenteric arteries were extracted for concentration-response curves (CRC) to phenylephrine [PE; in the presence or absence of L-NAME or indomethacin] and acetylcholine. The number of eggs and adult worms were significantly higher in the 10 DPI group than those of 30 DPI group. Augmented PE-induced contraction was seen after 30 DPI compared to 10 DPI or control group. Hypercontractility to PE was partially prevented by L-NAME and wholly abolished by indomethacin incubation. Endothelium-dependent relaxation and endothelial nitric oxide synthase expression were unchanged among groups. COX-1 and COX-2 display a different pattern of expression over the infection. Hypercontractility observed in mesenteric resistance arteries in the resolution time of S. venezuelensis infection may represent systemic damage, which can generate significant cardiovascular and gastrointestinal repercussions.

Nitric Oxide Donors as Potential Drugs for the Treatment of Vascular Diseases Due to Endothelium Dysfunction

Endothelial dysfunction and consequent vasoconstriction are a common condition in patients with hypertension and other cardiovascular diseases. Endothelial cells produce and release vasodilator substances that play a pivotal role in normal vascular tone. The mechanisms underlying endothelial dysfunction are multifactorial. However, enhanced reactive oxygen species (ROS) production and consequent vasoconstriction instead of endothelium-derived relaxant generation and consequent vasodilatation contribute to this dysfunction considerably. The main targets of the drugs that are currently used to treat vascular diseases concerning enzyme activities and protein functions that are impaired by endothelial nitric oxide synthase (eNOS) uncoupling and ROS production. Nitric oxide (NO) bioavailability can decrease due to deficient NO production by eNOS and/or NO release to vascular smooth muscle cells, which impairs endothelial function. Considering the NO cellular mechanisms, tackling the issue of eNOS uncoupling could avoid endothelial dysfunction: provision of the enzyme cofactor tetrahydrobiopterin (BH4) should elicit NO release from NO donors, to activate soluble guanylyl cyclase. This should increase cyclic guanosine-monophosphate (cGMP) generation and inhibit phosphodiesterases (especially PDE5) that selectively degrade cGMP. Consequently, protein kinase-G should be activated, and K+ channels should be phosphorylated and activated, which is crucial for cell membrane hyperpolarization and vasodilation and/or inhibition of ROS production. The present review summarizes the current concepts about the vascular cellular mechanisms that underlie endothelial dysfunction and which could be the target of drugs for the treatment of patients with cardiovascular disease.

Activation of the 5-HT7 receptor but not nitric oxide synthase is necessary for chronic 5-hydroxytryptamine-induced hypotension

NEW FINDINGS

What is the central question of this study? What mechanisms account for the hypotension observed during chronic elevations in circulating 5-hydroxytryptamine in rats? What is the main finding and its importance? Chronic 5-hydroxytryptamine-induced hypotension requires continued activation of the 5-HT₇ receptor subtype but does not require NO, an outcome that resolves previous conflicting results. Therapeutic interruption of the hypotensive actions of 5-HT under pathophysiological conditions can only be achieved through blockade of the 5-HT₇ receptor.

ABSTRACT

Low dose infusion of 5-hydroxytryptamine (5-HT) to rats causes both an acute and a chronic fall in arterial blood pressure. The 5-HT₇ receptor subtype plays a critical part in the observed hypotension. Acute (minutes to hours) 5-HT infusion shows no depressor role for nitric oxide (NO), but 5-HT depressor responses under chronic conditions suggest that NO production may be critical. We test the hypothesis that NO contributes to the chronic, but not the acute, depressor response to 5-HT. We compared the role of NO and 5-HT₇ receptors in 5-HT-induced hypotension under acute and chronic conditions in the same animal. Mean arterial pressure and heart rate were measured by radiotelemetry in conscious rats during 5 days of saline or 5-HT (25 μg kg^-1  min^-1 ; osmotic pump) infusion and for 2 days after infusion was stopped. To quantify the contributions of NO and the 5-HT₇ receptor to 5-HT-induced hypotension, the nitric oxide synthase (NOS) inhibitor l-NAME or the selective 5-HT₇ receptor antagonist SB-267790 were given at 1, 3 and 5 days of chronic infusion, and 1 day after 5-HT infusion pumps were removed. N^ω -Nitro-l-arginine methyl ester (l-NAME) caused a pressor response of the same magnitude in the absence or presence of 5-HT infusion. Conversely, SB-269970 did not affect mean arterial pressure in the absence of 5-HT infusion and reversed the 5-HT-induced depressor response at each time point. Our findings demonstrate that acute and chronic 5-HT-induced hypotension does not require NOS activation but does require continued activation of the 5-HT₇ receptor.

Vasodilation activity of dipfluzine metabolites in isolated rat basilar arteries and their underlying mechanisms

Identifying the metabolites of a drug has become an indispensable task in the development of new drugs. Dipfluzine (Dip) is a promising candidate for the treatment of cerebral vascular diseases and has 5 metabolites (M1∼M5) in rat urine and liver microsomes, but their biological activity is still unknown. Because selective cerebral vasodilation is a main role of Dip, we investigated the vasodilation of Dip and its 5 metabolites in isolated Sprague-Dawley (SD) male rat basilar arteries preconstricted with high-K⁺ or 5-HT. The results showed that only M1 possessed concentration-dependent inhibitory activity on the vasoconstriction of arteries with or without the endothelium, and M1 has a more potent vasodilatory effect than Dip on both contraction models. Like Dip, the vasodilatory mechanisms of M1 may be not only related to receptor-operated and voltage-dependent calcium ion channels of smooth muscle cells but also to the release of NO and EDHF from endothelial cells and the opening of Ca²⁺-activated K⁺ channels and ATP-sensitive potassium ion channels. Unlike Dip, the vasodilation mechanism of M1 is also related to the opening of voltage-sensitive K⁺ channel. Together with more selectivity to non-VDCC than Dip, this may partially explain why M1 has stronger vasodilatory effects than Dip. The mechanisms of vasodilation of Dip and M1 may result from the combined action of these or other factors, especially blocking non-endothelium dependent non-VDCC and endothelium dependent IK_Ca channels. These results point to the possibility that M1 provides synergism for the clinical use of Dip, which may inform the synthesis of new drugs.

TMEM98, a novel secretory protein, promotes endothelial cell adhesion as well as vascular smooth muscle cell proliferation and migration

Transmembrane protein 98 (TMEM98) is a novel gene, and its function has not been well investigated. In a prior study, we have shown that siRNA-mediated knockdown of TMEM98 inhibited interleukin-8 (IL-8) promoted endothelial cell (EC) adhesion, as well as vascular smooth muscle cell (VSMC) proliferation and migration in the vascular endothelial and smooth muscle cell dysfunction. Herein, we used gain- and loss-of-function approaches combined with biochemical techniques to further explore the role of TMEM98 in the vascular wall cell. The expression and secretion of TMEM98 was increased in cultured human umbilical vein endothelial cells (HUVECs) and VSMCs treated with IL-8 and platelet-derived growth factor-BB (PDGF-BB). Also, PDGF-BB secretion was increased in TMEM98-treated HUVECs and VSMCs. Thus, it appears that TMEM98 and PDGF-BB form a positive feedback loop in potentiation of EC adhesion, as well as VSMC proliferation and migration. Knockdown of TMEM98 mediated by siRNA inhibited PDGF-BB-promoted EC adhesion by downregulating the expression of ICAM-1 and VCAM-1, as well as impaired the proliferation and migration of VSMCs by suppressing the AKT/GSK3β/cyclin D1 signaling pathway and reducing the expression of β-catenin. Hence, TMEM98 promoted EC adhesion by inducing the expression of ICAM-1/VCAM-1 and triggered VSMC proliferation and migration by activating the ERK and AKT/GSK3β signaling pathways. Taken together, TMEM98 may serve as a potential therapeutic target for the clinical treatment of vascular endothelial and smooth muscle cell dysfunction.

NOX4 is a major regulator of cord blood-derived endothelial colony-forming cells which promotes post-ischaemic revascularization

AIMS

Cord blood-derived endothelial colony-forming cells (CB-ECFCs) are a defined progenitor population with established roles in vascular homeostasis and angiogenesis, which possess low immunogenicity and high potential for allogeneic therapy and are highly sensitive to regulation by reactive oxygen species (ROS). The aim of this study was to define the precise role of the major ROS-producing enzyme, NOX4 NADPH oxidase, in CB-ECFC vasoreparative function.

METHODS AND RESULTS

In vitro CB-ECFC migration (scratch-wound assay) and tubulogenesis (tube length, branch number) was enhanced by phorbol 12-myristate 13-acetate (PMA)-induced superoxide in a NOX-dependent manner. CB-ECFCs highly-expressed NOX4, which was further induced by PMA, whilst NOX4 siRNA and plasmid overexpression reduced and potentiated in vitro function, respectively. Increased ROS generation in NOX4-overexpressing CB-ECFCs (DCF fluorescence, flow cytometry) was specifically reduced by superoxide dismutase, highlighting induction of ROS-specific signalling. Laser Doppler imaging of mouse ischaemic hindlimbs at 7 days indicated that NOX4-knockdown CB-ECFCs inhibited blood flow recovery, which was enhanced by NOX4-overexpressing CB-ECFCs. Tissue analysis at 14 days revealed consistent alterations in vascular density (lectin expression) and eNOS protein despite clearance of injected CB-ECFCs, suggesting NOX4-mediated modulation of host tissue. Indeed, proteome array analysis indicated that NOX4-knockdown CB-ECFCs largely suppressed tissue angiogenesis, whilst NOX4-overexpressing CB-ECFCs up-regulated a number of pro-angiogenic factors specifically-linked with eNOS signalling, in parallel with equivalent modulation of NOX-dependent ROS generation, suggesting that CB-ECFC NOX4 signalling may promote host vascular repair.

CONCLUSION

Taken together, these findings indicate a key role for NOX4 in CB-ECFCs, thereby highlighting its potential as a target for enhancing their reparative function through therapeutic priming to support creation of a pro-reparative microenvironment and effective post-ischaemic revascularization.

Vascular Protective Effects of Xanthotoxin and Its Action Mechanism in Rat Aorta and Human Vascular Endothelial Cells

OBJECTIVE

Xanthotoxin (XAT) is a linear furanocoumarin mainly extracted from the plants Ammi majus L. XAT has been reported the apoptosis of tumor cells, anti-convulsant, neuroprotective effect, antioxidative activity, and vasorelaxant effects. This study aimed to investigate the vascular protective effects and underlying molecular mechanisms of XAT.

METHODS

XAT's activity was studied in rat thoracic aortas, isolated with aortic rings, and human umbilical vein endothelial cells (HUVECs).

RESULTS

XAT induced endothelium-dependent vasodilation in a concentration-dependent manner in the isolated rat thoracic aortas. Removal of endothelium or pretreatment of aortic rings with L-NAME, 1H-[1,2,4]-oxadiazolo-[4,3-a]-quinoxalin-1-one, and wortmannin significantly inhibited XAT-induced relaxation. In addition, treatment with thapsigargin, 2-aminoethyl diphenylborinate, Gd3+, and 4-aminopyridine markedly attenuated the XAT-induced vasorelaxation. XAT increased nitric oxide production and Akt- endothelial NOS (eNOS) phosphorylation in HUVECs. Moreover, XAT attenuated the expression of TNF-α-induced cell adhesion molecules such as intercellular adhesion molecule, vascular cell adhesion molecule-1, and E-selectin. However, this effect was attenuated by the eNOS inhibitors L-NAME and asymmetric dimethylarginine.

CONCLUSIONS

This study suggests that XAT induces vasorelaxation through the Akt-eNOS-cGMP pathway by activating the KV channel and inhibiting the L-type Ca2+ channel. Furthermore, XAT exerts an inhibitory effect on vascular inflammation, which is correlated with the observed vascular protective effects.

Effects of caffeine and caffeic acid on selected biochemical parameters in L-NAME-induced hypertensive rats

Biologically active compounds such as caffeine and caffeic acid can be obtained in plants especially cocoa and coffee. Hence, the combinatory effect of caffeine and caffeic acid as well as their individual effect were assessed on the activities of arginase, angiotensin-1-converting enzyme (ACE) as well as nitric oxide (NOx), and malondialdehyde (MDA) level in the Nω-Nitro-L-arginine-methylester (L-NAME)-induced hypertensive rats. The individual and combinatory effect of caffeine and caffeic acid were investigated in L-NAME-induced rats. Animals were grouped into eleven containing six animals each. Hemodynamic parameter was determined by tail-cuff plethysmography. Furthermore, the result showed a notable rise in ACE and arginase activities of L-NAME-induced group compared with the control group. However, pretreatment with test compounds lowered ACE, arginase activities, and MDA content with rise in NOx. This study supports that caffeine and caffeic acid combinations demonstrated antihypertensive properties by lowering the systolic blood pressure in L-NAME-induced rats. PRATICAL APPLICATIONS: This duo bioactive compounds; caffeine (alkaloid) and caffeic acid (phenolic acid) are lavishly distributed in coffee. Their cardiopotective and cardiomodulatory roles have been investigated due to their biological activities. As far as we are aware, this could be foremost in-depth study on the antihypertensive and cardioprotective effect of the combinations of caffeine and caffeic acid targeting the key enzymes system relevant to hypertension. Decreased ACE and arginase activities as well as high nitric oxide (NOx) and low MDA level may be associated with its antihypertensive effect. This present study suggests that the combinations of this phenolics and alkaloid compound might proffer a therapeutic strategy in the management of hypertension.

Hemodynamic forces enhance decidualization via endothelial-derived prostaglandin E2 and prostacyclin in a microfluidic model of the human endometrium

STUDY QUESTION

Does the uterine vasculature play a localized role in promoting stromal cell decidualization in the human endometrium?

SUMMARY ANSWER

Our study demonstrated that hemodynamic forces induced secretion of specific endothelial cell-derived prostanoids that enhanced endometrial perivascular decidualization via a paracrine mechanism.

WHAT IS KNOWN ALREADY

Differentiation of stromal cell fibroblasts into the specialized decidua of the placenta is a progesterone-dependent process; however, histologically, it has long been noted that the first morphological signs of decidualization appear in the perivascular stroma. These observations suggest that the human endometrial vasculature plays an active role in promoting stromal differentiation.

STUDY DESIGN, SIZE, DURATION

Primary human endometrial stromal cells were co-cultured for 14 days with primary uterine microvascular endothelial cells within a microfluidic Organ-on-Chip model of the endometrium.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Cultures were maintained with estradiol and a progestin, with or without continuous laminar perfusion to mimic hemodynamic forces derived from the blood flow. Some cultures additionally received exogenous agonist-mediated challenges. Decidualization in the microfluidic model was assessed morphologically and biochemically. ELISA was used to examine the culture effluent for expression of decidualization markers and prostaglandins. Immunofluorescence was used to monitor cyclooxygenase-2 expression in association with decidualization.

MAIN RESULTS AND THE ROLE OF CHANCE

A significantly enhanced stromal decidualization response was observed in the co-cultures when the endothelial cells were stimulated with hemodynamic forces (e.g. laminar shear stress) derived from controlled microfluidic perfusion (<0.001). Furthermore, the enhanced progestin-driven stromal differentiation was mediated via cyclooxygenase-2 and the paracrine action of prostaglandin E2 and prostacyclin. Altogether, these translational findings indicate that the vascular endothelium plays a key physiologic role during the early events of perivascular decidualization in the human endometrium.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

This report is largely an in vitro study. Although we were able to experimentally mimic hemodynamic forces in our microfluidic model, we have not yet determined the contribution of additional cell types to the decidualization process or determined the precise physiological rates of shear stress that the microvasculature of the endometrium undergoes in vivo.

WIDER IMPLICATIONS OF THE FINDINGS

Identification of specific endothelial-derived prostaglandins and their role during endometrial reproductive processes may have clinical utility as therapeutic targets for reproductive disorders such as infertility, endometriosis, adenomyosis, pre-eclampsia and poor pregnancy outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Veterans Affairs (I01 BX002853), the Bill and Melinda Gates Foundation Grand Challenges Exploration (OPP1159411), the Environmental Toxicology Training Grant (NIH T32 ES007028) and the Environmental Protection Agency STAR Center Grant (83573601).

CONFLICT OF INTEREST

The authors report no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Transient receptor potential vanilloid 4 channels as therapeutic targets in diabetes and diabetes-related complications

With an estimated 425 million diabetes patients worldwide in 2019, type 2 diabetes has reached a pandemic proportion and represents a major unmet medical need. A key determinant of the development and progression of type 2 diabetes is pancreatic -cell dysfunction, including the loss of cell mass, the impairment of insulin biosynthesis and inadequate exocytosis. Recent studies have shown that transient receptor potential vanilloid 4 (TRPV4), a Ca2+ -permeable non-selective cation channel, is involved in -cell replication, insulin production and secretion. TRPV4 agonists have insulinotropic activity in pancreatic -cell lines, but the prolonged activation of TRPV4 leads to -cell dysfunction and death. In addition, TRPV4 is involved in a wide variety of pathophysiological activities, and has been reported to play an important role in diabetes-related complications, such as obesity, cardiovascular diseases, diabetic retinopathy, nephropathy and neuropathy. In a rodent type 2 diabetes model, Trpv4 agonists promote vasodilation and improve cardiovascular function, whereas Trpv4 antagonists reduce high-fat diet-induced obesity, insulin resistance, diabetic nephropathy, retinopathy and neuropathy. These findings raise interest in using TRPV4 as a therapeutic target for type 2 diabetes. In this review, we intend to summarize the latest findings regarding the role of TRPV4 in diabetes as well as diabetes-related conditions, and to evaluate its potential as a therapeutic target for diabetes and diabetes-related diseases.

Role of ROS/RNS in Preeclampsia: Are Connexins the Missing Piece?

Preeclampsia is a pregnancy complication that appears after 20 weeks of gestation and is characterized by hypertension and proteinuria, affecting both mother and offspring. The cellular and molecular mechanisms that cause the development of preeclampsia are poorly understood. An important feature of preeclampsia is an increase in oxygen and nitrogen derived free radicals (reactive oxygen species/reactive nitrogen species (ROS/RNS), which seem to be central players setting the development and progression of preeclampsia. Cell-to-cell communication may be disrupted as well. Connexins (Cxs), a family of transmembrane proteins that form hemichannels and gap junction channels (GJCs), are essential in paracrine and autocrine cell communication, allowing the movement of signaling molecules between cells as well as between the cytoplasm and the extracellular media. GJCs and hemichannels are fundamental for communication between endothelial and smooth muscle cells and, therefore, in the control of vascular contraction and relaxation. In systemic vasculature, the activity of GJCs and hemichannels is modulated by ROS and RNS. Cxs participate in the development of the placenta and are expressed in placental vasculature. However, it is unknown whether Cxs are modulated by ROS/RNS in the placenta, or whether this potential modulation contributes to the pathogenesis of preeclampsia. Our review addresses the possible role of Cxs in preeclampsia, and the plausible modulation of Cxs-formed channels by ROS and RNS. We suggest these factors may contribute to the development of preeclampsia.

Synthesis and Modeling Studies of Furoxan Coupled Spiro-Isoquinolino Piperidine Derivatives as NO Releasing PDE 5 Inhibitors

Nitric oxide (NO) is considered to be one of the most important intracellular messengers that play an active role as neurotransmitter in regulation of various cardiovascular physiological and pathological processes. Nitric oxide (NO) is a major factor in penile erectile function. NO exerts a relaxing action on corpus cavernosum and penile arteries by activating smooth muscle soluble guanylate cyclase and increasing the intracellular concentration of cyclic guanosine monophosphate (cGMP). Phophodiesterase (PDE) inhibitors have potential therapeutic applications. NO hybridization has been found to improve and extend the pharmacological properties of the parental compound. The present study describes the synthesis of novel furoxan coupled spiro-isoquinolino-piperidine derivatives and their smooth muscle relaxant activity. The study reveals that, particularly 10d (1.50 ± 0.6) and 10g (1.65 ± 0.7) are moderate PDE 5 inhibitors as compared to Sidenafil (1.43 ± 0.5). The observed effect was explained by molecular modelling studies on phosphodiesterase.

Hypotensive effect of Eugenia dysenterica leaf extract is primarily related to its vascular action: The possible underlying mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Eugenia dysenterica (ED) leaves are used in Brazil to treat cardiac diseases; however, there are no scientific data describing the effects of this species on cardiac activity.

AIM OF THE STUDY

To investigate the effect of ED aqueous leaf extract (EDLE) on hear rate (HR) and mean arterial pressure (MAP) of anaesthetised rats and its underlying mechanism of action.

MATERIAL AND METHODS

EDLE was analysed, and its proanthocyanidin composition was determined. After performing dose-effect curves for EDLE on HR and MAP, EDLE-induced hypotension was evaluated before and after atropine (AT), L-N(ω)-nitro-L-arginine methyl ester (L-NAME), hexamethonium (HXT), indomethacin (IND), carbenoxolone (CBX), or nifedipine (NFD) administration. The effect of proanthocyanidin-depleted extract (EDLE/P-) was also determined and compared to that of the EDLE with proanthocyanidins.

RESULTS

EDLE decreased the MAP in a dose-dependent manner; HR was decreased only with the highest and most toxic dose. Only CBX and NFD decreased EDLE-induced hypotension. Five polymeric series of proanthocyanidins were identified, which were mainly constituted by procyanidin and prodelphinidin units with B-type linkage and up to 12 flavan-3-ol units. EDLE/P- induced hypotension did not differ from that induced by EDLE.

CONCLUSIONS

The cardiovascular effects of EDLE were primarily related to its vascular action. EDLE-induced hypotensive effect appeared to involve L-type calcium channel blockage as well as myoendothelial gap junction signalling. The higher molecular weight proanthocyanidins from EDLE are unlikely to contribute to its cardiovascular effect.

Why the endothelium? The endothelium as a target to reduce diabetes-associated vascular disease

Over the past 66 years, our knowledge of the role of the endothelium in the regulation of cardiovascular function and dysfunction has advanced from the assumption that it is a single layer of cells that serves as a barrier between the blood stream and vascular smooth muscle to an understanding of its role as an essential endocrine-like organ. In terms of historical contributions, we pay particular credit to (1) the Canadian scientist Dr. Rudolf Altschul who, based on pathological changes in the appearance of the endothelium, advanced the argument in 1954 that "one is only as old as one's endothelium" and (2) the American scientist Dr. Robert Furchgott, a 1998 Nobel Prize winner in Physiology or Medicine, who identified the importance of the endothelium in the regulation of blood flow. This review provides a brief history of how our knowledge of endothelial function has advanced and now recognize that the endothelium produces a plethora of signaling molecules possessing paracrine, autocrine, and, arguably, systemic hormone functions. In addition, the endothelium is a therapeutic target for the anti-diabetic drugs metformin, glucagon-like peptide I (GLP-1) receptor agonists, and inhibitors of the sodium-glucose cotransporter 2 (SGLT2) that offset the vascular disease associated with diabetes.

Pu-Erh Tea Relaxes the Thoracic Aorta of Rats by Reducing Intracellular Calcium

Previous studies suggested that pu-erh tea aqueous extract could lower blood pressure and ameliorate hypertension symptoms. However, the antihypertension mechanisms of pu-erh tea remain unclear. In this work, the direct effects of pu-erh tea on vessels and cells were investigated by detecting isometric tension and intracellular calcium ([Ca²⁺]_i), respectively. Additionally, to identify the main active components, the aqueous extract of pu-erh was separated by organic solvents to obtain various fractions, and the effects of these fractions on arteries were assessed. The results showed that pu-erh aqueous extract vasodilated rat thoracic aortas preconstricted by phenylephrine or KCl. These vasodilation effects were not significantly affected by the removal of the endothelium or by preincubation with potassium channel blockers (tetraethylammonium, glibenclamide, aminopyridine, or barium chloride). Moreover, pu-erh aqueous extract could reduce the vessel contractibility induced by CaCl₂ and phenylephrine under KCl-depolarizing or Ca²⁺-free buffer conditions, respectively. Furthermore, pu-erh aqueous extract attenuated the KCl-induced increase in [Ca²⁺]_i in cultured rat aortic smooth muscle A7r5 cells. In addition, the chloroform precipitate of pu-erh aqueous extract produced the most potent vasodilation. Theabrownins (the characteristic components of pu-erh tea) accounted for 41.91 ± 1.09 % of the chloroform precipitate and vasodilated arteries in an endothelium-independent manner. In addition, the vasodilation effect of caffeine was verified. In conclusion, theabrownins and caffeine should be the two main active components in pu-erh tea. Pu-erh aqueous extract vasodilated arteries in an endothelium-independent manner, which might partly be attributed to the decrease in extracellular Ca²⁺ influx. Moreover, our study provided data on the potential mechanism of the hypotensive actions of pu-erh tea, which might improve our understanding of the effect of pu-erh tea on the prevention and treatment of hypertension.

Intensity-dependent effect of pulsed and continuous therapeutic ultrasound on endothelial function: a randomised crossover clinical trial

Background/Aims

The aim of this study was to evaluate the effects of different intensities and waveforms of therapeutic ultrasound on endothelial function in typically healthy participants.

Methods

A total of 15 participants were evaluated over 2 consecutive days. Different intensities of continuous and pulsed (20% duty cycle) 1-MHz ultrasound were applied to the brachial artery for 5 minutes each. Endothelial function was measured using flow-mediated dilation technique before and immediately after ultrasound was applied.

Results

Compared to baseline values, endothelium-dependent vasodilation increased with both continuous (2.8%) and pulsed (1.6%) ultrasound at an intensity of 0.4 W/cm2SPTA. At 1.2 W/cm2SPTA, endothelium-dependent vasodilation was 4.1% above baseline for pulsed and 5.3% above baseline for continuous waveforms. There was no additional increase in vasodilation at intensities above 1.2 W/cm2SPTA. The percentage of endothelium-dependent vasodilation was similar for the all of the different waveforms studied.

Conclusions

Both continuous and pulsed ultrasound waveforms promote endothelium-dependent vasodilation. There was a dose-dependent increase in vasodilation at intensities from 0.4 W/cm2SPTA to 1.2 W/cm2SPTA. Pulsed is more efficient than continuous ultrasound because it produces the same effect on endothelium-dependent vasodilation while employing 20% of the energy applied with continuous ultrasound.

SKA-31, an activator of Ca2+-activated K+ channels, improves cardiovascular function in aging

Aging represents an independent risk factor for the development of cardiovascular disease, and is associated with complex structural and functional alterations in the vasculature, such as endothelial dysfunction. Small- and intermediate-conductance, Ca²⁺-activated K⁺ channels (KCa2.3 and KCa3.1, respectively) are prominently expressed in the vascular endothelium, and pharmacological activators of these channels induce robust vasodilation upon acute exposure in isolated arteries and intact animals. However, the effects of prolonged in vivo administration of such compounds are unknown. In our study, we hypothesized that such treatment would ameliorate aging-related cardiovascular deficits. Aged (∼18 months) male Sprague Dawley rats were treated daily with either vehicle or the KCa channel activator SKA-31 (10 mg/kg, intraperitoneal injection; n = 6/group) for 8 weeks, followed by echocardiography, arterial pressure myography, immune cell and plasma cytokine characterization, and tissue histology. Our results show that SKA-31 administration improved endothelium-dependent vasodilation, reduced agonist-induced vascular contractility, and prevented the aging-associated declines in cardiac ejection fraction, stroke volume and fractional shortening, and further improved the expression of endothelial KCa channels and associated cell signalling components to levels similar to those observed in young male rats (∼5 months at end of study). SKA-31 administration did not promote pro-inflammatory changes in either T cell populations or plasma cytokines/chemokines, and we observed no overt tissue histopathology in heart, kidney, aorta, brain, liver and spleen. SKA-31 treatment in young rats had little to no effect on vascular reactivity, select protein expression, tissue histology, plasma cytokines/chemokines or immune cell properties. Collectively, these data demonstrate that administration of the KCa channel activator SKA-31 improved aging-related cardiovascular function, without adversely affecting the immune system or promoting tissue toxicity.

Novel Biomarkers of Early Atherosclerotic Changes for Personalised Prevention of Cardiovascular Disease in Cervical Cancer and Human Papillomavirus Infection

Cervical cancer is associated with a causative role of human papillomavirus (HPV), which is a highly prevalent infection. Recently, women with a genital HPV infection were found to have increased incidence of cardiovascular diseases (CVD), including severe cardiovascular events such as myocardial infarction and stroke. The pathomechanisms of this relation are not yet fully understood, and may significantly affect the health of a large part of the population. Accelerated atherosclerosis is assumed to play a key role in the pathophysiology of this relationship. To identify high-risk groups of the population, it is necessary to stratify the CVD risk. Current algorithms, as widely used for the estimation of CVD risk, seem to be limited by the individual misclassification of high-risk subjects. However, personalised prediction of cardiovascular events is missing. Regarding HPV-related CVD, identification of novel sensitive biomarkers reflecting early atherosclerotic changes could be of major importance for such personalised cardiovascular risk prediction. Therefore, this review focuses on the pathomechanisms leading to HPV-related cardiovascular diseases with respect to atherosclerosis, and the description of potential novel biomarkers to detect the earliest atherosclerotic changes important for the prevention of CVD in HPV infection and cervical cancer.