Cellular and molecular mechanisms of endothelial cell dysfunction

Long term effects of soluble endoglin and mild hypercholesterolemia in mice hearts

Soluble endoglin (sEng) released into the circulation was suggested to be related to cardiovascular based pathologies. It was demonstrated that a combination of high sEng levels and long-term exposure (six months) to high fat diet (HFD) resulted in aggravation of endothelial dysfunction in the aorta. Thus, in this study, we hypothesized that a similar experimental design would affect the heart morphology, TGFβ signaling, inflammation, fibrosis, oxidative stress and eNOS signaling in myocardium in transgenic mice overexpressing human sEng. Three-month-old female transgenic mice overexpressing human sEng in plasma (Sol-Eng+ high) and their age-matched littermates with low levels of human sEng (Sol-Eng+ low) were fed a high-fat diet containing 1.25% of cholesterol and 40% of fat for six months. A blood analysis was performed, and the heart samples were analyzed by qRT-PCR and Western blot. The results of this study showed no effects of sEng and HFD on myocardial morphology/hypertrophy/fibrosis. However, the expression of pSmad2/3 and p-eNOS was reduced in Sol-Eng+ high mice. On the other hand, sEng and HFD did not significantly affect the expression of selected members of TGFβ signaling (membrane endoglin, TGFβRII, ALK-5, ALK-1, Id-1, PAI-1), inflammation (VCAM-1, ICAM-1), oxidative stress (NQO1, HO-1) and heart remodeling (PDGFβ, COL1A1, β-MHC). In conclusion, the results of this study confirmed that sEng, even combined with a high-fat diet inducing hypercholesterolemia administered for six months, does not affect the structure of the heart with respect to hypertrophy, fibrosis, inflammation and oxidative stress. Interestingly, pSmad2/3/p-eNOS signaling was reduced in both the heart in this study and the aorta in the previous study, suggesting a possible alteration of NO metabolism caused by six months exposure to high sEng levels and HFD. Thus, we might conclude that sEng combined with a high-fat diet might be related to the alteration of NO production due to altered pSmad2/3/p-eNOS signaling in the heart and aorta.

AGE-RAGE Axis in the Pathophysiology of Chronic Lower Limb Ischemia and a Novel Strategy for Its Treatment

This review focuses on the role of advanced glycation end products (AGEs) and its cell receptor (RAGE) and soluble receptor (sRAGE) in the pathogenesis of chronic lower limb ischemia (CLLI) and its treatment. CLLI is associated with atherosclerosis in lower limb arteries. AGE-RAGE axis which comprises of AGE, RAGE, and sRAGE has been implicated in atherosclerosis and restenosis. It may be involved in atherosclerosis of lower limb resulting in CLLI. Serum and tissue levels of AGE, and expression of RAGE are elevated, and the serum levels of sRAGE are decreased in CLLI. It is known that AGE, and AGE-RAGE interaction increase the generation of various atherogenic factors including reactive oxygen species, nuclear factor-kappa B, cell adhesion molecules, cytokines, monocyte chemoattractant protein-1, granulocyte macrophage-colony stimulating factor, and growth factors. sRAGE acts as antiatherogenic factor because it reduces the generation of AGE-RAGE-induced atherogenic factors. Treatment of CLLI should be targeted at lowering AGE levels through reduction of dietary intake of AGE, prevention of AGE formation and degradation of AGE, suppression of RAGE expression, blockade of AGE-RAGE binding, elevation of sRAGE by upregulating sRAGE expression, and exogenous administration of sRAGE, and use of antioxidants. In conclusion, AGE-RAGE stress defined as a shift in the balance between stressors (AGE, RAGE) and antistressor (sRAGE) in favor of stressors, initiates the development of atherosclerosis resulting in CLLI. Treatment modalities would include reduction of AGE levels and RAGE expression, RAGE blocker, elevation of sRAGE, and antioxidants for prevention, regression, and slowing of progression of CLLI.

Inflammation in Peritoneal Dialysis: A Latin-American Perspective

Peritoneal dialysis (PD) patients present an extremely high mortality rate, but the mechanisms mediating the increased risk of mortality observed in this group of patients are still largely unknown, which limits the perspective of effective therapeutic strategies. The leading hypothesis that tries to explain this high mortality risk is that PD patients are exposed to a number of traditional risk factors for cardiovascular disease (CVD) already at the onset of their chronic kidney disease (CKD), since many of these risk factors are common to both CVD and CKD. Of particular importance, chronic inflammation recently emerged as an important novel risk factor related to multiple complications of CKD. There are many stimuli of the inflammatory response in CKD patients, such as fluid overload, decreased cytokine clearance, presence of uremia-modified proteins, presence of chronic infections, metabolic disturbances (including hyperglycemia), obesity. Many of these factors are related to PD. Latin America has made some progress in economic issues; however, a large portion of the population is still living in poverty, in poor sanitary conditions, and with many health-related issues, such as an increasing elderly population, low birth weights, and increasingly high energy intake in the adult population, which, in combination with changes in lifestyle, has provoked an increase in the prevalence of obesity, diabetes, and CVD. Therefore, in Latin America, there seems to be a peculiar situation combining high prevalence of low education level, poor sanitary conditions, and poverty with increases in obesity, diabetes, and sedentary lifestyle. Since inflammation and mortality risk are intimately related to both sides of those health issues, in this review we aim to analyze the peculiarities of inflammation and mortality risk in the Latin-American PD population.

Transplant Outcomes of Donation After Circulatory Death Livers Recovered With Versus Without Premortem Heparin Administration

Premortem heparin administration during donation after circulatory death (DCD) organ recovery is thought to optimize liver perfusion. However, premortem heparinization is not universally practiced in the United States and limited data exist regarding its utility. US registry data were accessed between January 1, 2003, and March 10, 2017, and 2 cohorts were ascertained: (1) DCD donor livers recovered for transplantation (n = 5495) and (2) liver-only adult transplant recipients of DCD livers (n = 3754). Exclusions were donor unknown heparin status (n = 40), positive donor hepatitis B surface antigen (n = 4) and hepatitis C virus (n = 120) serologies, and for the outcomes analysis, livers placed outside the United States (n = 10). Discard rates and graft outcomes were examined from cohorts 1 and 2, respectively. Of 5495 DCD livers recovered for transplant, 589 (10.7%) donors did not receive premortem heparin (no heparin) and the remaining 4906 (89.3%) received heparin (heparin). Liver discard was similar between the no heparin (30.6%) and heparin groups (30.8%; P = 0.90). Heparin status was not associated with liver discard on multivariate analysis (adjusted odds ratio, 0.97; 95% confidence interval [CI], 0.80-1.18 P = 0.76). The cumulative probability of overall graft survival was lower in the no heparin group relative to the heparin group (P < 0.05), and this finding persisted on multivariate analysis. No heparin group transplants had an 18% higher hazard of overall graft failure compared with those that received heparin (adjusted hazard ratio, 1.18; 95% CI, 1.01-1.38; P < 0.05). In conclusion, organ recovery heparin administration status was not associated with liver discard. Failure to pretreat organ donors with premortem heparin correlates with worse liver transplant graft survival compared with heparin-treated livers.

N-Acetylcysteine Does Not Improve the Endothelial and Smooth Muscle Function in the Human Saphenous Vein

Oxidative stress can lead to vein graft dysfunction in the saphenous vein. This ex vivo study is aimed to compare the effects of increasing concentrations of the antioxidant N-acetylcysteine (NAC) with heparinized saline (HS) on endothelial and smooth muscle function in the human saphenous vein. Long saphenous vein segment obtained during infrainguinal bypass surgery was divided into 7 rings; 1 immersed in HS and the remaining 6 in increasing NAC concentrations (0.0025%, 0.005%, 0.01%, 0.02%, 0.03%, and 0.04%). Rings were mounted in an organ bath, and relaxant responses to acetylcholine and sodium nitroprusside were assessed through isometric tension studies. Endothelium-dependent relaxations were observed in 77 vein segments from 11 patients. No significant difference was seen in veins treated with either lower NAC concentrations (0.0025%, 0.005%, 0.01%, 0.02%, and 0.03%) or HS. However, HS-treated veins showed significantly better relaxation compared to those treated with maximum (0.04%) NAC ( P < .05). Endothelium-independent relaxations were observed in 91 segments from 13 patients. No difference in relaxation was observed between veins treated with HS or any of the NAC concentrations. In conclusion, lower NAC concentrations do not offer better endothelial protection than HS, whereas the highest NAC concentration has a detrimental effect on endothelium-dependent relaxation. Moreover, NAC did not show beneficial effect on direct smooth muscle relaxation.

Effects of Grape Seed Proanthocyanidin Extract on Vascular Endothelial Function in Participants with Prehypertension: A Randomized, Double-Blind, Placebo-Controlled Study

This study aimed to investigate the effects of grape seed proanthocyanidin extract (GSPE) on blood pressure and vascular endothelial function in middle-aged Japanese adults with prehypertension. We conducted a randomized, double-blind, placebo-controlled study on 6 men and 24 women aged 40-64 years old. The participants were randomized to receive tablets containing either low-dose (200 mg/day) or high-dose (400 mg/day) GSPE, or placebo, for 12 weeks. Systolic and diastolic blood pressures (SBP and DBP, respectively), brachial flow-mediated dilation (FMD), and other cardiovascular parameters were measured before and after 4, 8, and 12 weeks of treatment. The mean SBP in the high-dose group significantly decreased by 13 mmHg after 12 weeks (P = 0.028), although FMD did not change. In an ad hoc analysis of non-smoking participants (n = 21), the mean SBP, DBP, stiffness parameter β, distensibility, incremental elastic modulus (Einc), and pulse wave velocity (PWV) also significantly improved in the high-dose group after 12 weeks. Changes in Einc and PWV from baseline to 12 weeks were significantly greater in the high-dose group than in the placebo group (Einc, P = 0.023; PWV, P = 0.03). GSPE consumption could help maintain vascular elasticity and normal blood pressure in this population.

Association Between the Angiotensin-Converting Enzyme Gene Insertion/Deletion Polymorphism and Avascular Necrosis of the Femoral Head

Objective: This study investigated the association between the angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and avascular necrosis of the femoral head (ANFH). Materials and Methods: The ACE gene I/D polymorphism was determined in 279 nontraumatic, ANFH Han Chinese patients (divided into idiopathic and steroid- and alcohol-induced subgroups) and 276 age- and gender-matched healthy controls using the polymerase chain reaction. Results: The frequencies of the ACE DD genotype and D allele were significantly higher among the ANFH patients as a whole and also in the idiopathic and steroid- and alcohol-induced ANFH subgroups compared to healthy controls (p < 0.05 for all). Additionally, the DD genotype, compared with the ID+II, ID, and II genotypes, conferred a higher risk of developing ANFH across all clinical subgroups (p < 0.001, odds ratio [OR] = 2.508; p < 0.001, OR = 2.072; p < 0.001, OR = 3.684, respectively) as well in each of the subgroups examined individually, including the idiopathic subgroup (p < 0.001, OR = 2.579; p < 0.001, OR = 2.091; p < 0.001, OR = 3.994, respectively), the steroid-induced subgroup (p = 0.005, OR = 2.345; p = 0.031, OR = 2.050; p = 0.007, OR = 3.000, respectively), and the alcohol-induced subgroup (p < 0.001, OR = 2.488; p = 0.012, OR = 2.050; p = 0.011, OR = 2.659, respectively) of ANFH patients. The ID genotype, compared with the II genotype, conferred a higher risk across all subtypes analyzed together, and in the idiopathic subgroup (p = 0.013, OR = 1.778; p = 0.028, OR = 1.910) analyzed separately. Additionally, the D allele, in comparison with the I allele, conferred a relatively higher risk across all subgroups (p < 0.001, OR = 2.101) as well as in each of the three subgroups examined individually (idiopathic: p < 0.001, OR = 2.178; steroid-induced: p = 0.003, OR = 1.910; and alcohol-induced: p < 0.001, OR = 2.094). Conclusion: The ACE DD and ID genotypes and D allele may be risk factors for susceptibility to ANFH in the Chinese population.

Inhibition of MPO (Myeloperoxidase) Attenuates Endothelial Dysfunction in Mouse Models of Vascular Inflammation and Atherosclerosis

Objective—

Inflammation-driven endothelial dysfunction initiates and contributes to the progression of atherosclerosis, and MPO (myeloperoxidase) has been implicated as a potential culprit. On release by circulating phagocytes, MPO is thought to contribute to endothelial dysfunction by limiting NO bioavailability via formation of reactive oxidants including hypochlorous acid. However, it remains largely untested whether specific pharmacological inhibition of MPO attenuates endothelial dysfunction. We, therefore, tested the ability of a mechanism-based MPO inhibitor, AZM198, to inhibit endothelial dysfunction in models of vascular inflammation.

Approach and Results—

Three models of inflammation were used: femoral cuff, the tandem stenosis model of plaque rupture in Apoe −/− mice, and C57BL/6J mice fed a high-fat, high-carbohydrate diet as a model of insulin resistance. Endothelial dysfunction was observed in all 3 models, and oral administration of AZM198 significantly improved endothelial function in the femoral cuff and tandem stenosis models only. Improvement in endothelial function was associated with decreased arterial MPO activity, determined by the in vivo conversion of hydroethidine to 2-chloroethidium, without affecting circulating inflammatory cytokines or arterial MPO content. Mechanistic studies in Mpo −/− mice confirmed the contribution of MPO to endothelial dysfunction and revealed oxidation of sGC (soluble guanylyl cyclase) as the underlying cause of the observed limited NO bioavailability.

Conclusions—

Pharmacological inhibition of MPO is a potential strategy to limit endothelial dysfunction in vascular inflammation.

Visual Overview—

An online visual overview is available for this article.

Development of a Nitric Oxide-Responsive Labeling Reagent for Proteome Analysis of Live Cells

Nitric oxide (NO) is a pleiotropic signaling molecule involved in the regulation of diverse physiological and pathophysiological mechanisms in cardiovascular, nervous, and immunological systems. To understand the biological functions of NO in detail, comprehensive characterization of proteins found in high-NO concentration environments is crucial. Herein, we describe the design of NO-responsive protein labeling reagents based on N-alkoxyacyl- o-phenylenediamine as an optimal reactive scaffold. The designed molecules can label proteins in murine macrophage cells in response to endogenously produced NO. The combination of NO-responsive protein labeling and liquid chromatography-tandem mass spectrometry technology allowed the characterization of the proteome under NO-generated conditions. Moreover, we demonstrated that our reagent was able to selectively mark and be used to fluorescently visualize NO-producing cells in a mixed cell culture system.

Exploring the role of body mass index in relationship of serum nitric oxide and advanced glycation end products in apparently healthy subjects

This study aimed to identify any association of serum nitric oxide (NO) and advanced glycation end products (AGEs) with body mass index (BMI) in apparently healthy subjects. In this cross-sectional study, participants were 90 apparently healthy subjects, categorized into three BMI groups as follows: BMI≤19.5 (n = 21), 19.6≤BMI≤24.9 (n = 35), and BMI≥25 (n = 34). Serum levels of NO were measured by griess reaction method. Determination of serum pentosidine and carboxymethyllysine (CML) was done using ELISA. Median (95% confidence interval [CI]: lower- upper) of serum NO in subjects with BMI≥25 were 68.94 (CI: 55.01–70.56) μmol/L, which was higher compared with 19.6≤BMI≤24.9 and BMI≤19.5 groups (22.65 (CI: 19.29–28.17) μmol/L and 8.00 (CI: 9.12–29.58) μmol/L, respectively). Serum NO positively correlated with BMI in total subjects (r = 0.585, p<0.001), which this correlation was significant in both male and female groups (r = 0.735, p<0.001 and r = 0.476, p = 0.001, respectively). Serum pentosidine and CML were significantly lower in subjects with higher BMI. Further, BMI showed negative correlations with pentosidine and CML (r = -0.363, p<0.001 and r = -0.484, p<0.001, respectively). There were not any significant differences in serum NO, pentosidine, and CML levels between sex groups. After adjusting the effects of confounders (BMI, sex, age, and waist to hip ratio), serum NO significantly correlated with serum pentosidine and CML (r = -0.319, p = 0.003 and r = -0.433, p<0.001, respectively). It is concluded that higher BMI is accompanied by increased serum NO and suppressed pentosidine and CML.

The Role of Traditional Chinese Medicine in the Regulation of Oxidative Stress in Treating Coronary Heart Disease

Oxidative stress has been closely related with coronary artery disease. In coronary heart disease (CHD), an excess of reactive oxygen species (ROS) production generates endothelial cell and smooth muscle functional disorders, leading to a disequilibrium between the antioxidant capacity and prooxidants. ROS also leads to inflammatory signal activation and mitochondria-mediated apoptosis, which can promote and increase the occurrence and development of CHD. There are several kinds of antioxidative and small molecular systems of antioxidants, such as β-carotene, ascorbic acid, α-tocopherol, and reduced glutathione (GSH). Studies have shown that antioxidant treatment was effective and decreased the risk of CHD, but the effect of the treatment varies greatly. Traditional Chinese medicine (TCM) has been utilized for thousands of years in China and is becoming increasingly popular all over the world, especially for the treatments of cardiovascular diseases. This review will concentrate on the evidence of the action mechanism of TCM in preventing CHD by modulating oxidative stress-related signaling pathways.

Cerebrovascular reactivity and cerebral perfusion of rats with acute liver failure: role of L-glutamine and asymmetric dimethylarginine in L-arginine-induced response

Cerebral blood flow (CBF) is impaired in acute liver failure (ALF), however, the complexity of the underlying mechanisms has often led to inconclusive interpretations. Regulation of CBF depends at least partially on variations in the local brain L-arginine concentration and/or its metabolic rate. In ALF, other factors, like an increased concentration of asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor and elevated level of L-glutamine, may contribute to CBF alteration. This study demonstrated strong differences in the reactivity of the middle cerebral arteries and their response to extravascular L-arginine application between vessels isolated from rats with thioacetamide (TAA)-induced ALF and control animals. Our results also showed the decrease in the cerebral perfusion in TAA rats measured by arterial spin labeling perfusion magnetic resonance. Subsequently, we aimed to investigate the importance of balance between the concentration of ADMA and L-arginine in the CBF regulation. In vivo, intraperitoneal L-arginine administration in TAA rats corrected: (i) decrease in cerebral perfusion, (ii) decrease in brain extracellular L-arginine/ADMA ratio and (iii) increase in brain L-glutamine concentration. Our study implicates that impaired vascular tone of cerebral arteries is most likely associated with exposure to high ADMA and L-glutamine levels resulting in limited availability of L-arginine and might be responsible for reduced cerebral perfusion observed in ALF.

The Main Determinants of Diabetes Mellitus Vascular Complications: Endothelial Dysfunction and Platelet Hyperaggregation

Diabetes mellitus is a common disease that affects 3–5% of the general population in Italy. In some countries of northern Europe or in North America, it can even affect 6–8% of the population. Of great concern is that the number of cases of diabetes is constantly increasing, probably due to the increase in obesity and the sedentary nature of the population. According to the World Health Organization, in the year 2030 there will be 360 million people with diabetes, compared to 170 million in 2000. This has important repercussions on the lives of patients and their families, and on health systems that offer assistance to patients. In this review, we try to describe in an organized way the pathophysiological continuity between diabetes mellitus, endothelial dysfunction, and platelet hyperaggregation, highlighting the main molecular mechanisms involved and the interconnections.

Role of Hyperglycemia-Induced Advanced Glycation End Product (AGE) Accumulation in Atherosclerosis

There is a growing body of evidence that cumulative hyperglycemic exposure plays a central role in the development and progression of atherosclerotic cardiovascular disease in diabetic patients. Monosaccharides, such as glucose, fructose, and glyceraldehyde can react non-enzymatically with amino groups of proteins, lipids, nucleic acids to form senescent macromolecules termed advanced glycation end products (AGEs), whose formation and accumulation has been known to progress in diabetic patients, especially in those with a long history of disease. The sustained accumulation of AGEs could contribute to the phenomenon of metabolic memory or legacy effects observed in long-term follow-up clinical studies of diabetic patients. AGE modification alters the structural integrity and function of various types of macromolecules, and interaction of AGEs with a receptor for AGEs (RAGE) has been shown to evoke inflammatory and thrombotic reactions. Therefore, the AGE–RAGE axis is a novel therapeutic target of atherosclerotic cardiovascular disease in diabetic patients. In this paper, we briefly review the pathological role of AGEs and their receptor RAGE system in atherosclerotic cardiovascular disease, including peripheral artery disease and discuss the clinical utility of measuring AGEs in evaluating the severity of atherosclerosis in patients with diabetes.

Responses of Endothelial Cells Towards Ischemic Conditioning Following Acute Myocardial Infarction

One of the primary therapeutic goals of modern cardiology is to design strategies aimed at minimizing myocardial infarct size and optimizing cardiac function following acute myocardial infarction (AMI). Patients with AMI who underwent reperfusion therapy display dysfunction of the coronary endothelium. Consequently, ischemic endothelial cells become more permeable and weaken their natural anti-thrombotic and anti-inflammatory potential. Ischemia-reperfusion injury (IRI) is associated with activation of the humoral and cellular components of the hemostatic and innate immune system, and also with excessive production of reactive oxygen species (ROS), the inhibition of nitric oxide synthase, and with inflammatory processes. Given its essential role in the regulation of vascular homeostasis, involving platelets and leukocytes among others, dysfunctional endothelium can lead to increased risk of coronary vasospasm and thrombosis. Endothelial dysfunction can be prevented by ischemic conditioning with a protective intervention based on limited intermittent periods of ischemia and reperfusion. The molecular mechanisms and signal transduction pathways underlying conditioning phenomena in the coronary endothelium have been described as involving less ROS production, reduced adhesion of neutrophils to endothelial cells and diminished inflammatory reactions. This review summarizes our current understanding of the cellular and molecular mechanisms regulating IRI-affected and -damaged coronary endothelium, and how ischemic conditioning may preserve its function.

Involvement of CD8+ T cell subsets in early response to vascular injury in patients with peripheral artery disease in vivo

AIMS

Adaptive immunity is critical in vascular remodelling following arterial injury. We hypothesized that acute changes in T cells at a percutaneous transluminal angioplasty (PTA) site could serve as an index of their potential interaction with the injured vascular wall.

METHODS AND RESULTS

T cell subsets were characterised in 45 patients with Rutherford 3-4 peripheral artery disease (PAD) undergoing PTA. Direct angioplasty catheter blood sampling was performed before and immediately after the procedure. PTA was associated with an acute reduction of α/β-TcR CD8+ T cells. Further characterisation revealed significant reduction in pro-atherosclerotic CD28nullCD57+ T cells, effector (CD45RA+CCR7-) and effector memory (CD45RA-CCR7-) cells, in addition to cells bearing activation (CD69, CD38) and tissue homing/adhesion markers (CD38, CCR5).

CONCLUSIONS

The acute reduction observed here is likely due to the adhesion of cells to the injured vascular wall, suggesting that immunosenescent, activated effector CD8+ cells have a role in the early vascular injury immune response following PTA in PAD patients.

Physiology of nitric oxide in the respiratory system

Nitric oxide (NO) is an important endogenous neurotransmitter and mediator. It participates in regulation of physiological processes in different organ systems including airways. Therefore, it is important to clarify its role in the regulation of both airway and vascular smooth muscle, neurotransmission and neurotoxicity, mucus transport, lung development and in the. surfactant production. The bioactivity of NO is highly variable and depends on many factors: the presence and activity of NO-producing enzymes, activity of competitive enzymes (e.g. arginase), the amount of substrate for the NO production, the presence of reactive oxygen species and others. All of these can change NO primary physiological role into potentially harmful. The borderline between them is very fragile and in many cases not entirely clear. For this reason, the research focuses on a comprehensive understanding of NO synthesis and its metabolic pathways, genetic polymorphisms of NO synthesizing enzymes and related effects. Research is also motivated by frequent use of exhaled NO monitoring in the clinical manifestations of respiratory diseases. The review focuses on the latest knowledge about the production and function of this mediator and understanding the basic physiological processes in the airways.

Association of endothelial dysfunction with cardiovascular risk factors and new-onset diabetes mellitus in patients with hypertension

Asymmetric dimethylarginine (ADMA), which is the main endogenous inhibitor of nitric oxide synthase, plays a critical role in the process of endothelial dysfunction. The authors evaluated the association between high plasma ADMA levels in patients with hypertension and the presence of cardiovascular risk factors and the development of type 2 diabetes mellitus (DM) and cardiovascular outcomes, including death. The authors evaluated 191 patients with hypertension who were stratified into two groups according to the median value of basal ADMA: those with high levels of plasma ADMA (>0.55 μmol/L) and low levels of plasma ADMA (≤0.55 μmol/L) who were prospectively evaluated over 5.8 years. High ADMA levels were seen in patients with higher weight, body mass index, waist circumference, triglycerides, uric acid, and high-sensitivity C-reactive protein, and lower levels of high-density lipoprotein cholesterol and in patients with type 2 DM. There was an association between high plasma ADMA levels and the occurrence of cardiovascular death. In a subgroup of patients with hypertension free from metabolic syndrome and DM at baseline, there was an association between high ADMA levels and the development of type 2 DM. This study confirms the association of high plasma ADMA levels and the presence of cardiovascular risk factors in patients with hypertension and suggests a positive predictive value of high plasma ADMA levels for cardiovascular death in patients with hypertension and also for the development of type 2 DM in a subgroup of patients with hypertension free from metabolic abnormalities.

Etanercept restores vasocontractile sensitivity affected by mesenteric ischemia reperfusion

BACKGROUND

The aim of the study is to evaluate in vivo and in vitro effects of etanercept, a soluble tumor necrosis factor receptor, on the contractile responses of superior mesenteric artery in an experimental mesenteric ischemia and reperfusion model.

MATERIAL AND METHODS

After obtaining animal ethics committee approval, 24 Sprague-Dawley rats were allocated to three groups. Control group (Gr C, n = 6) underwent a sham operation, whereas ischemia/reperfusion and treatment groups underwent 90 min ischemia and 24-h reperfusion (Gr I/R, n = 12; Gr I/R+E, n = 6). The treatment group received 5 mg/kg etanercept intravenously at the beginning of reperfusion. At the end of reperfusion, all animals were sacrificed, and third branch of superior mesenteric artery was dissected for evaluation of contractile responses. In vitro effects of etanercept on vasocontractile responses were also evaluated. The excised ileums were analyzed under light microscope. Two-way analysis of variance following Bonferroni post hoc test was used for evaluation of contractile responses.

RESULTS

Endothelin-1 and phenylephrine-mediated vasocontractile sensitivity were found increased in Gr I/R when compared with Gr C. Both intravenous administration and organ bath incubation of etanercept decreased the sensitivity of contractile agents for Gr I/R. Mucosal injury, lamina propria disintegration, and denuded villous tips were observed in Gr I/R, whereas the epithelial injury and the subepithelial edema were found to be milder in Gr I/R+E.

CONCLUSIONS

Etanercept can be a promising agent in mesenteric ischemic reperfusion injury as it does not only inhibit inflammation by blocking tumor necrosis factor-α in circulation but also restores vascular contractility during reflow. These findings support an unexplained recuperative effect of drug beyond its anti-inflammatory effects.

Effects of neuromuscular electrical stimulation in patients with heart failure - review

Research conducted in the last two decades suggests that neuromuscular electrical stimulation of the lower limb muscles (NMES) may be a "bridge" to conventional exercise or an alternative for patients with advanced chronic heart failure (CHF), non-compliant or non-responsive to physical training. Through stimulating the work of the skeletal muscles, NMES increases the functional capacity, muscle mass and endurance in patients with CHF. A beneficial effect of NMES on functional capacity, vascular endothelial function, quality of life and aerobic enzymes activity has been shown. A significant benefit of this novel therapy in heart failure is the fact that the procedure can be home-based, after prior guidance of the patient.

Oxidative burden in familial hypercholesterolemia

Familial hypercholesterolemia (FH) is a genetic disorder characterized by high serum levels of low-density lipoprotein cholesterol (LDL-c). FH is characterized by accelerated development of atherosclerosis and represents the most frequent hereditary cause of premature coronary heart disease. Mutations of the LDL receptor gene are the genetic signature of FH, resulting in abnormal levels of circulating LDLs. Moreover, FH promotes the generation of reactive oxygen species (ROS) which is another key mechanism involved in atherosclerosis development and progression. The aim of this narrative review is to update the current knowledge on the pathophysiological mechanisms linking FH to ROS generation and their detrimental impact on atherosclerotic pathophysiology. With this purpose, we reviewed experimental and clinical data on the association between FH and OS and the functional role of OS as a promoter of inflammation and atherosclerosis. In this regard, oxidant species such as oxidized LDL, malondialdehyde, ROS, and isoprostanes emerged as leading mediators of the oxidative injury in FH. In conclusion, targeting oxidative stress may be a promising therapeutic strategy to reduce atherogenesis in patients with FH.

Relation of asymmetrical dimethylarginine levels with renal outcomes in hypertensive patients with and without type 2 diabetes mellitus

AIM

The aim of the study was to evaluate the association between high plasma ADMA levels, a biomarker of endothelial dysfunction, with the progression of albuminuria and chronic kidney disease (CKD) in hypertensive patients, with and without type 2 diabetes mellitus.

METHODS

We successfully contacted 213 of 644 patients who had been evaluated between 2004 and 2005 and for whom basal data were available. After the exclusion of 51 patients, 162 hypertensive patients who were free from albuminuria were stratified into the following 4 groups according to the presence of diabetes and plasma ADMA percentiles: general hypertensive patients with high levels of plasma ADMA (>P4 or ADMA > 0.61 μmol/L), general hypertensive patients with low levels of plasma ADMA (≤P4), diabetic hypertensive patients with high levels of plasma ADMA (>P4), and diabetic hypertensive patients with low levels of plasma ADMA (≤P4).

RESULTS

The patients were prospectively evaluated over 5.8 years. High ADMA levels were associated with the progression of albuminuria in hypertensive patients, with and without type 2 diabetes. Major increases in the ADMA value during follow-up were associated with the progression of CKD, and direct correlations between ADMA changes and GFR changes were observed in the whole group and in the subgroup of diabetic patients.

CONCLUSIONS

We suggest that high plasma ADMA levels might be a biomarker of renal disease progression and might even be an early predictor of albuminuria and its progression to the late stages of renal disease in hypertensive and diabetic hypertensive patients.

Hemostasis, endothelial stress, inflammation, and the metabolic syndrome

Obesity and the metabolic syndrome (MS) are two of the pressing healthcare problems of our time. The MS is defined as increased abdominal obesity in concert with elevated fasting glucose levels, insulin resistance, elevated blood pressure, and plasma lipids. It is a key risk factor for type 2 diabetes mellitus (T2DM) and for cardiovascular complications and mortality. Here, we review work demonstrating that various aspects of coagulation and hemostasis, as well as vascular reactivity and function, become impaired progressively during chronic ingestion of a western diet, but also acutely after meals. We outline that both T2DM and cardiovascular disease should be viewed as inflammatory diseases and describe that chronic overload of free fatty acids and glucose can trigger inflammatory pathways directly or via increased production of ROS. We propose that since endothelial stress and increases in platelet activity precede inflammation and overt symptoms of the MS, they are likely the first hit. This suggests that endothelial activation and insulin resistance are probably causative in the observed chronic low-level metabolic inflammation, and thus both metabolic and cardiovascular complications linked to consumption of a western diet.

Metformin treatment decreases nitroxidative stress, restores nitric oxide bioavailability and endothelial function beyond glucose control

Reduction of nitric oxide (NO), a potent vasodilator, and an increase in cytotoxic peroxynitrite (ONOO^-) may be associated with the uncoupling of NO synthase (eNOS) and endothelial cell (EC) dysfunction. In addition to its effect on glucose control, metformin, may also directly benefit in the restoration of the function of eNOS and EC. Obese Zucker rats were administered vehicle or 300 mg/kg/day metformin for 4 weeks. NO concentration [NO] and ONOO^- concentration [ONOO^-] were measured in aortic and glomerular endothelial cells from Zucker rats in vitro. Compared with controls, aortic and glomerular endothelial [NO] was reduced by 32% and 41%, while [ONOO^-] release increased 79% and 69%, respectively. Metformin treatment increased aortic and glomerular endothelial [NO] by 37% and 57%, respectively, while decreasing [ONOO^-] by 32% and 34%, compared with vehicle-treated animals. Treatment with metformin significantly restored the balance in the [NO]/[ONOO^-] ratio with 101% and 138% increase for aortic and glomerular endothelial cells, respectively. Fasting glucose levels were not significantly changed. These findings indicate that metformin therapy has a direct and beneficial effect on arterial and renal EC function in obese rats, including enhanced NO release and reduced nitroxidative stress, beyond any effects on fasting glucose levels.

Dietary Plant Sterols Supplementation Increases In Vivo Nitrite and Nitrate Production in Healthy Adults: A Randomized, Controlled Study

A randomized, double-blinded, placebo-controlled and crossover study was conducted to simultaneously measure the effects, 3 h after consumption and after 4-wk daily exposure to plant sterols-enriched food product, on in vivo nitrite and nitrate production in healthy adults. Eighteen healthy participants (67% female, 35.3 [mean] ± 9.5 [SD] years, mean body mass index 22.8 kg/m² ) received 2 soy milk (20 g) treatments daily: placebo and one containing 2.0 g free plant sterols equivalent of their palmityl esters (β-sitosterol, 55%; campesterol, 29%; and stigmasterol, 23%). Nitrite and nitrate concentrations were measured in the blood plasma and urine, using stable isotope-labeled gas chromatography-mass spectrometry. L-arginine and asymmetric dimethylarginine concentrations in blood serum were measured using commercially available enzyme immunoassays. Nitrite and nitrate concentrations in blood plasma (nitrite 5.83 ± 0.50 vs. 4.52 ± 0.27; nitrate 15.78 ± 0.96 vs. 13.43 ± 0.81 μmol/L) and urine (nitrite 1.12 ± 0.22 vs. 0.92 ± 0.36, nitrate 12.23 ± 1.15 vs. 9.71 ± 2.04 μmol/L) were significantly elevated after 4-wk plant sterols supplementation Placebo and 3-h treatments did not affect the blood plasma and urinary concentrations of nitrite and nitrate. Circulating levels of L-arginine and asymmetric dimethylarginine were unchanged in the placebo and treatment arms. Total plant sterols, β-Sitosterol, campesterol, and stigmasterol concentrations were significantly elevated after 4-wk treatments compared to the placebo and 3-h treatments. Blood plasma nitrite and nitrate concentrations correlated significantly with the plasma total and specific plant sterol concentrations. Our results suggest that dietary plant sterols, in the combination used, can upregulate nitrite, and nitrate production in vivo.

Selenium in the prevention of atherosclerosis and its underlying mechanisms

Atherosclerosis and related cardiovascular diseases (CVDs) represent the greatest threats to human health worldwide. Selenium, an essential trace element, is incorporated into selenoproteins that play a crucial role in human health and disease. Although findings from a limited number of randomized trials have been inconsistent and cannot support a protective role of Se supplementation in CVDs, prospective observational studies have generally shown a significant inverse association between selenium or selenoprotein status and CVD risk. Furthermore, a benefit of selenium supplementation in the prevention of CVDs has been seen in population with low baseline selenium status. Evidence from animal studies shows consistent results that selenium and selenoproteins might prevent experimental atherosclerosis, which can be explained by the molecular and cellular effects of selenium observed both in animal models and cell cultures. Selenoproteins of particular relevance to atherosclerosis are glutathione peroxidases, thioredoxin reductase 1, selenoprotein P, selenoprotein S. The present review is focusing on the existing evidence that supports the concept that optimal selenium intake can prevent atherosclerosis. Its underlying mechanisms include inhibiting oxidative stress, modulating inflammation, suppressing endothelial dysfunction, and protecting vascular cells against apoptosis and calcification. However, the benefit of selenium supplementation in the prevention of atherosclerosis remains insufficiently documented so far. Future studies with regard to the effects of selenium supplementation on atherosclerosis should consider many factors, especially the baseline selenium status, the dose and forms of selenium supplementation, and the selenoprotein genotype. Additionally, much more studies are needed to confirm the roles of selenoproteins in atherosclerosis prevention and clarify the underlying mechanisms.

Postprandial hyperglycemia and postprandial hypertriglyceridemia in type 2 diabetes

Postprandial glucose level is an independent risk factor for cardiovascular disease that exerts effects greater than glucose levels at fasting state, whereas increase in serum triglyceride level, under both fasting and postprandial conditions, contributes to the development of arteriosclerosis. Insulin resistance is a prevailing cause of abnormalities in postabsorptive excursion of blood glucose and postprandial lipid profile. Excess fat deposition renders a vicious cycle of hyperglycemia and hypertriglyceridemia in the postprandial state, and both of which are contributors to atherosclerotic change of vessels especially in patients with type 2 diabetes mellitus. Several therapeutic approaches for ameliorating each of these abnormalities have been attempted, including various antidiabetic agents or new compounds targeting lipid metabolism.

Application of galangin, an active component of Alpinia officinarum Hance (Zingiberaceae), for use in drug-eluting stents

In clinical pathology, stent interposition is used to treat vascular disease but can lead to restenosis. Drug-eluting stents (DES) are most commonly used to suppress restenosis but can also have side effects. Therefore, we investigated the anti-proliferative effect and its possible target in vitro and in vivo. We found that Alpinia officinarum Hance (AO) extract efficiently inhibited VSMC proliferation by arresting the transition from the G₀/G₁ to the S phase via the up-regulation of p27^KIP1 expression. Galangin (GA) was determined to be a significant component of this extract, with the same anti-proliferative activity as the raw extract. Immunoblotting and immunofluorescence staining showed that both the AO extract and GA targeted the up-regulation of p27^KIP1 expression. Therefore, we next examined the effect of these compounds in a cuff-injured neointimal hyperplasia model in vivo. In this animal model, both the AO extract and GA completely suppressed the neointima formation, and this inhibitory effect was also demonstrated to target the up-regulation of p27^KIP1, including the suppression of proliferating cell nuclear antigen expression. Our findings indicate that AO extract and GA have a potent anti-proliferative activity, targeting the up-regulation of p27 expression. Thus, GA may represent an alternative medicine for use in DES.

Lipid levels and risk of venous thrombosis: results from the MEGA-study

The relationship between lipid levels and risk of venous thrombosis is not well established. We aimed to assess the association between several lipids and risk of venous thrombosis using data from a population-based case-control study, and to evaluate the underlying mechanism, considering confounding by common risk factors and mediation via hemostatic factors and C-reactive protein. From the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis (MEGA) study, 2234 patients with a first venous thrombosis and 2873 controls were included. Percentile categories of total/low-density lipoprotein/high-density lipoprotein cholesterol, triglycerides, and apolipoproteins B and A1 were established in controls (<10th, 10th-25th, 25th-75th [reference], 75th-90th, >90th percentile). In age- and sex-adjusted models, decreasing levels of apolipoproteins B and A1 were dose-dependently associated with increased thrombosis risk, with odds ratios of 1.35 (95% confidence interval 1.12-1.62) and 1.50 (95% confidence interval 1.25-1.79) for the lowest category versus the reference category, respectively. The dose-response relation remained with further adjustment for body mass index, estrogen use, statin use, and diabetes. Although apolipoproteins B and A1 were associated with several hemostatic factors and C-reactive protein, none explained the increased risk in mediation analyses. The other lipids were not associated with venous thrombosis risk. In conclusion, decreasing levels of apolipoproteins B and A1 were associated with increased risk of venous thrombosis. Our findings are consistent with experimental data on the anticoagulant properties of apolipoproteins B and A1. These findings need to be confirmed and the underlying mechanism further investigated.

Fasudil ameliorates endothelial dysfunction in streptozotocin-induced diabetic rats: a possible role of Rho kinase

Endothelial dysfunction is a major contributor to the pathogenesis of vascular disease in diabetes mellitus and RhoA/Rho-kinase (ROCK) system appears to play a crucial role in this setting. The present study was conducted to investigate the effect of the selective ROCK inhibitor, fasudil, on diabetes-related endothelial dysfunction and elucidated its underlying mechanism(s). Diabetes was induced by a single intraperitoneal injection of streptozotocin (STZ, 50 mg/kg), and fasudil (5 mg/kg per day) was orally administered for 8 weeks. Our results showed that fasudil administration attenuated the increased activity/expression of ROCK (627.5 ± 27 vs. 247.8 ± 19.1) and the NADPH oxidase subunits, NOX2 and p47phox, in diabetic rat aorta. Fasudil could reduce the elevated tumor necrosis factor (TNF)-α (70.2 ± 14.1 vs. 25.3 ± 5.2) and transforming growth factor (TGF-β) levels and restored the deficit in antioxidant level of the diabetic aorta. Additionally, fasudil markedly improved the endothelial dysfunction in the diabetic aorta (73.8 ± 8.1 vs. 47.42 ± 8.69) and corrected the dysregulated endothelial nitric oxide (eNOS) expression. In conclusion, the present study demonstrates that fasudil effectively ameliorates the endothelial dysfunction in STZ-induced diabetic rats through inhibition of the Rho/ROCK pathway and thereby reducing the TNF-α-mediated NADPH oxidase activation.

Chromatin-modifying agents convert fibroblasts to OCT4+ and VEGFR-2+ capillary tube-forming cells

RATIONALE

The human epigenome is plastic. The goal of this study was to address if fibroblast cells can be epigenetically modified to promote neovessel formation.

METHODS AND RESULTS

Here, we used highly abundant human adult dermal fibroblast cells (hADFCs) that were treated with the chromatin-modifying agents 5-aza-2'-deoxycytidine and trichostatin A, and subsequently subjected to differentiation by activating Wnt signaling. Our results show that these epigenetically modified hADFCs increasingly expressed β-catenin, pluripotency factor octamer-binding transcription factor-4 (OCT4, also known as POU5F1), and endothelial cell (EC) marker called vascular endothelial growth factor receptor-2 (VEGFR-2, also known as Fetal Liver Kinase-1). In microscopic analysis, β-catenin localized to cell-cell contact points, while OCT4 was found to be localized primarily to the nucleus of these cells. Furthermore, in a chromatin immunoprecipitation experiment, OCT4 bound to the VEGFR-2/FLK1 promoter. Finally, these modified hADFCs also transduced Wnt signaling. Importantly, on a two-dimensional (2D) gel substrate, a subset of the converted cells formed vascular network-like structures in the presence of VEGF.

CONCLUSION

Chromatin-modifying agents converted hADFCs to OCT4+ and VEGFR-2+ capillary tube-forming cells in a 2D matrix in VEGF-dependent manner.

Central Role of Metabolism in Endothelial Cell Function and Vascular Disease

The importance of endothelial cell (EC) metabolism and its regulatory role in the angiogenic behavior of ECs during vessel formation and in the function of different EC subtypes determined by different vascular beds has been recognized only in the last few years. Even more importantly, apart from a role of nitric oxide and reactive oxygen species in EC dysfunction, deregulations of EC metabolism in disease only recently received increasing attention. Although comprehensive metabolic characterization of ECs still needs further investigation, the concept of targeting EC metabolism to treat vascular disease is emerging. In this overview, we summarize EC-specific metabolic pathways, describe the current knowledge on their deregulation in vascular diseases, and give an outlook on how vascular endothelial metabolism can serve as a target to normalize deregulated endothelium.

Ablation of Interferon Regulatory Factor 3 Protects Against Atherosclerosis in Apolipoprotein E-Deficient Mice

The secretion of adhesion molecules by endothelial cells, as well as the subsequent infiltration of macrophages, determines the initiation and progression of atherosclerosis. Accumulating evidence suggests that IRF3 (interferon regulatory factor 3) is required for the induction of proinflammatory cytokines and for endothelial cell proliferation. However, the effect and underlying mechanism of IRF3 on atherogenesis remain unknown. Our results demonstrated a moderate-to-strong immunoreactivity effect associated with IRF3 in the endothelium and macrophages of the atherosclerotic plaques in patients with coronary heart disease and in hyperlipidemic mice. IRF3^-/-ApoE^-/- mice showed significantly decreased atherosclerotic lesions in the whole aorta, aortic sinus, and brachiocephalic arteries. The bone marrow transplantation further suggested that the amelioration of atherosclerosis might be attributed to the effects of IRF3 deficiency mainly in endothelial cells, as well as in macrophages. The enhanced stability of atherosclerotic plaques in IRF3^-/-ApoE^-/- mice was characterized by the reduction of necrotic core size, macrophage infiltration, and lipids, which was accompanied by increased collagen and smooth muscle cell content. Furthermore, multiple proinflammatory cytokines showed a marked decrease in IRF3^-/-ApoE^-/- mice. Mechanistically, IRF3 deficiency suppresses the secretion of VCAM-1 (vascular cell adhesion molecule 1) and the expression of ICAM-1 (intercellular adhesion molecule 1) by directly binding to the ICAM-1 promoter, which subsequently attenuates macrophage infiltration. Thus, our study suggests that IRF3 might be a potential target for the treatment of atherosclerosis development.

The Top 12 Advances in Vascular Medicine

In the past decade, impressive strides have been made in the diagnosis and management of atherosclerotic, aneurysmal, and thromboembolic diseases, thanks in large part to the explosive growth in both vascular biology and clinical vascular medicine. We review what we consider to be the top 12 advances in this field: the discovery of nitric oxide, the metabolic syndrome, new thrombophilic disorders, therapeutic angiogenesis, endoluminal treatment of chronic venous disease, and a variety of drugs, including sildenafil, cilostazol, low-molecular-weight heparins, oral direct thrombin inhibitors, clopidogrel, statins, and angiotensin-converting enzyme inhibitors and angiotensin-receptor blocking agents.

Modifying effect of intravenous laser therapy on the protein expression of arginase and epidermal growth factor receptor in type 2 diabetic patients

The epidermal growth factor receptor (EGFR) signaling pathway may be involved in cell activation and may influence the neuronal microenvironment, microglia activation, and production of proinflammatory cytokines. Arginase and nitric oxide synthase (NOS) both use L-arginine as a common substrate. Decreasing the arginase expression may increase L-arginine consumption by NOS and increase nitric oxide (NO) synthesis. Intravenous laser blood irradiation (ILBI) is an effective systemic treatment for different pathologies including diabetes mellitus. Previous studies have shown that low-level laser therapy can have an effect on the release of certain cytokines and growth factors. The aim of this study was to evaluate the effects of ILBI on the expression of arginase and epidermal growth factor receptor in type 2 diabetic patients. We used 630 nm red laser light, 1.5 mW, continuous mode, intravenously for 30 min in 13 type 2 diabetic patients and compared their blood samples using the flow cytometry technique, before and after ILBI. The difference between the percentage of cells before and after therapy was analyzed using repeated-measures ANOVA, and the relationship between EGFR and arginase expression in blood and tissue was evaluated by calculating the Pearson correlation coefficient. We found a significant decrease in the expression of both arginase- and EGFR-positive cells after laser therapy (P < 0.01). In conclusion, laser therapy may have a beneficial effect for diabetic patients via decreasing arginase expression and activation of the NOS/NO pathway which increases NO production and vasodilation, and decreasing EGFR expression which may reduce neuroinflammation and its secondary damages.

Reactive Oxygen Species: A Key Hallmark of Cardiovascular Disease

Cardiovascular diseases (CVDs) have been the prime cause of mortality worldwide for decades. However, the underlying mechanism of their pathogenesis is not fully clear yet. It has been already established that reactive oxygen species (ROS) play a vital role in the progression of CVDs. ROS are chemically unstable reactive free radicals containing oxygen, normally produced by xanthine oxidase, nicotinamide adenine dinucleotide phosphate oxidase, lipoxygenases, or mitochondria or due to the uncoupling of nitric oxide synthase in vascular cells. When the equilibrium between production of free radicals and antioxidant capacity of human physiology gets altered due to several pathophysiological conditions, oxidative stress is induced, which in turn leads to tissue injury. This review focuses on pathways behind the production of ROS, its involvement in various intracellular signaling cascades leading to several cardiovascular disorders (endothelial dysfunction, ischemia-reperfusion, and atherosclerosis), methods for its detection, and therapeutic strategies for treatment of CVDs targeting the sources of ROS. The information generated by this review aims to provide updated insights into the understanding of the mechanisms behind cardiovascular complications mediated by ROS.