The endothelium: a new target for therapy

Effects of hydrogen peroxide on endothelial function in three-dimensional hydrogel vascular model and regulation mechanism of polar protein Par3

Three-dimensional (3D) cell cultures better reflect the function of endothelial cells (ECs) than two-dimensional (2D) cultures. In recent years, studies have found that ECs cultured in a 3D luminal structure can mimic the biological characteristics and phenotypes of vascular ECs, thus making it more suitable for endothelial dysfunction research. In this study, we used a 3D model and 2D tissue culture polystyrene (TCP) to investigate the effects of cell polarity on hydrogen peroxide (H2O2)-induced endothelial dysfunction and its related mechanisms. We observed the cell morphology, oxidative stress, and barrier and endothelial function of human umbilical vein endothelial cells (HUVECs) in 3D and 2D cultures. We then used Illumina to detect the differentially expressed genes in the 3D-cultured HUVEC with and without H2O2 stimulation, using ClusterProfiler for Gene Ontology (GO) function enrichment analysis and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway enrichment analysis of differentially expressed genes. Finally, we explored the role and mechanism of polar protein partitioning defective protein 3 (Par3) in the regulation of ECs. ECs were inoculated into the 3D hydrogel channel; after stimulation with H2O2, the morphology of HUVECs changed, the boundary was blurred, the expression of intercellular junction proteins decreased, and the barrier function of the EC layer was damaged. 3D culture increased the oxidative stress response of cells stimulated by H2O2 compared to 2D TCPs. The polarity-related protein Par3 and cell division control protein 42 (CDC42) were screened using bioinformatics analysis, and western blotting was used to verify the results. Par3 knockdown significantly suppressed claudin1 (CLDN1) and vascular endothelial cadherin (VE-cadherin). These results suggest that the polar protein Par3 can protect H2O2-induced vascular ECs from damage by regulating CLDN1 and VE-cadherin.

Endothelial Dysfunction and Ischemia-Modified Albumin Levels in Males with Diabetic and Nondiabetic Erectile Dysfunction

In this study, we aimed to determine endothelial dysfunction and ischemia-modified albumin (IMA) levels in patients diagnosed with erectile dysfunction (ED) and to examine the relationship between these and diabetes disease. 86 male patients (46 patients with diabetes, age: $51.5\pm 9.2$ and 40 patients with nondiabetes (control group), age: $54.78\pm 12.2$ ) were included in the study. IMA, a new indicator of tissue ischemia and oxidative stress, was checked. Superoxide dismutase (SOD) activity, another oxidative stress indicator, was examined. Endothelin-1 (ET-1), one of the parameters of endothelial dysfunction, was measured. Additionally, endothelial function was evaluated with flow-mediated vasodilatation (FMD). Student’s $t$ -test was used for statistical evaluation. $p$ values less than 0.05 were considered statistically significant. SOD activity was significantly lower in the diabetic group than in the control group, and ET-1 was significantly higher ( $p<0.001$ ). IMA was found to be significantly higher in the diabetic group than the control group ( $p<0.001$ ). FMD was significantly lower in diabetic group compared to the control group ( $p<0.002$ ). According to our findings, the co-occurrence of erectile dysfunction and diabetes demonstrates a complex condition that includes endothelial dysfunction, oxidative stress, and tissue ischemia. When the correlation of indicators, which are markers, was examined, the severity of the co-occurrence of diabetes and erectile dysfunction was again demonstrated.

In Vitro SARS-CoV-2 Infection of Microvascular Endothelial Cells: Effect on Pro-Inflammatory Cytokine and Chemokine Release

In the novel pandemic of Coronavirus Disease 2019, high levels of pro-inflammatory cytokines lead to endothelial activation and dysfunction, promoting a pro-coagulative state, thrombotic events, and microvasculature injuries. The aim of the present work was to investigate the effect of SARS-CoV-2 on pro-inflammatory cytokines, tissue factor, and chemokine release, with Human Microvascular Endothelial Cells (HMEC-1). ACE2 receptor expression was evaluated by western blot analysis. SARS-CoV-2 infection was assessed by one-step RT-PCR until 7 days post-infection (p.i.), and by Transmission Electron Microscopy (TEM). IL-6, TNF-α, IL-8, IFN-α, and hTF mRNA expression levels were detected by RT-PCR, while cytokine release was evaluated by ELISA. HMEC-1 expressed ACE2 receptor and SARS-CoV-2 infection showed a constant viral load. TEM analysis showed virions localized in the cytoplasm. Expression of IL-6 at 24 h and IFN-α mRNA at 24 h and 48 h p.i. was higher in infected than uninfected HMEC-1 (p < 0.05). IL-6 levels were significantly higher in supernatants from infected HMEC-1 (p < 0.001) at 24 h, 48 h, and 72 h p.i., while IL-8 levels were significantly lower at 24 h p.i. (p < 0.001). These data indicate that in vitro microvascular endothelial cells are susceptible to SARS-CoV-2 infection but slightly contribute to viral amplification. However, SARS-CoV-2 infection might trigger the increase of pro-inflammatory mediators.

The impact of COVID-19 on the comorbidities: A review of recent updates for combating it

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SARS-CoV-2 can also affect organs other than the lungs, including the brain, heart, and gastrointestinal system.

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Patients with Cancer, HIV, COPD, neurological, and CVDs are more prone to the COVID-19 associated complications, leading to a drastic rise in morbidity and mortality.

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Elderly and pre-existing polypharmacy patients have worsened COVID-19 associated complications. When a person with comorbidity is infected with SARS-CoV-2, it becomes more dangerous, and managing these patients with adequate medical care is critical to their survival.

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A co-morbid person should adhere to preventive measures to reduce mortality, including regular handwashing with soap or using an alcohol-based hand sanitizer, minimizing in person contact and practicing social distance, wearing a face mask in public places, and avoiding going to public places unless essential are among the precautional measures.

Coronavirus disease is caused by the SARS-CoV-2 virus. The virus first appeared in Wuhan (China) in December 2019 and has spread globally. Till now, it affected 269 million people with 5.3 million deaths in 224 countries and territories. With the emergence of variants like Omicron, the COVID-19 cases grew exponentially, with thousands of deaths. The general symptoms of COVID-19 include fever, sore throat, cough, lung infections, and, in severe cases, acute respiratory distress syndrome, sepsis, and death. SARS-CoV-2 predominantly affects the lung, but it can also affect other organs such as the brain, heart, and gastrointestinal system. It is observed that 75 % of hospitalized COVID-19 patients have at least one COVID-19 associated comorbidity. The most common reported comorbidities are hypertension, NDs, diabetes, cancer, endothelial dysfunction, and CVDs. Moreover, older and pre-existing polypharmacy patients have worsened COVID-19 associated complications. SARS-CoV-2 also results in the hypercoagulability issues like gangrene, stroke, pulmonary embolism, and other associated complications. This review aims to provide the latest information on the impact of the COVID-19 on pre-existing comorbidities such as CVDs, NDs, COPD, and other complications. This review will help us to understand the current scenario of COVID-19 and comorbidities; thus, it will play an important role in the management and decision-making efforts to tackle such complications.

Aberrant stromal tissue factor localisation and mycolactone-driven vascular dysfunction, exacerbated by IL-1β, are linked to fibrin formation in Buruli ulcer lesions

Buruli ulcer (BU) is a neglected tropical disease caused by subcutaneous infection with Mycobacterium ulcerans and its exotoxin mycolactone. BU displays coagulative necrosis and widespread fibrin deposition in affected skin tissues. Despite this, the role of the vasculature in BU pathogenesis remains almost completely unexplored. We hypothesise that fibrin-driven ischemia can be an ‘indirect’ route to mycolactone-dependent tissue necrosis by a mechanism involving vascular dysfunction. Here, we tracked >900 vessels within contiguous tissue sections from eight BU patient biopsies. Our aim was to evaluate their vascular and coagulation biomarker phenotype and explore potential links to fibrin deposition. We also integrated this with our understanding of mycolactone’s mechanism of action at Sec61 and its impact on proteins involved in maintaining normal vascular function. Our findings showed that endothelial cell dysfunction is common in skin tissue adjacent to necrotic regions. There was little evidence of primary haemostasis, perhaps due to mycolactone-dependent depletion of endothelial von Willebrand factor. Instead, fibrin staining appeared to be linked to the extrinsic pathway activator, tissue factor (TF). There was significantly greater than expected fibrin staining around vessels that had TF staining within the stroma, and this correlated with the distance it extended from the vessel basement membrane. TF-induced fibrin deposition in these locations would require plasma proteins outside of vessels, therefore we investigated whether mycolactone could increase vascular permeability in vitro. This was indeed the case, and leakage was further exacerbated by IL-1β. Mycolactone caused the loss of endothelial adherens and tight junctions by the depletion of VE-cadherin, TIE-1, TIE-2 and JAM-C; all Sec61-dependent proteins. Taken together, our findings suggest that both vascular and lymphatic vessels in BU lesions become “leaky” during infection, due to the unique action of mycolactone, allowing TF-containing structures and plasma proteins into skin tissue, ultimately leading to local coagulopathy and tissue ischemia.

To date, the debilitating skin disease Buruli ulcer remains a public health concern and financial burden in low or middle-income countries, especially in tropical regions. Late diagnosis is frequent in remote areas, perhaps due to the painlessness of the disease. Hence patients often present with large, destructive opened ulcers leading to delayed wound closure or even lifelong disability. The infectious agent produces a toxin called mycolactone that drives the disease. We previously found evidence that the vascular system is disrupted by mycolactone in these lesions, and now we have further explored potential explanations for these findings by looking at the expression of vascular markers in BU. In a detailed analysis of patient skin punch biopsies, we identified distinct expression patterns of certain proteins and found that tissue factor, which initiates the so-called extrinsic pathway of blood clotting, is particularly important. Mycolactone is able to disrupt the barrier function of the endothelium, further aggravating the diseased phenotype, which may explain how clotting factors access the tissue. Altogether, such localised hypercoagulation in Buruli ulcer skin lesions may contribute to the development of the lesion.

Characterization of a functional endothelial super-enhancer that regulates ADAMTS18 and angiogenesis

Super-enhancers are clusters of enhancers associated with cell lineage. They can be powerful gene-regulators and may be useful in cell-type specific viral-vector development. Here, we have screened for endothelial super-enhancers and identified an enhancer from within a cluster that conferred 5–70-fold increase in transgene expression. Importantly, CRISPR/Cas9 deletion of enhancers demonstrated regulation of ADAMTS18, corresponding to evidence of chromatin contacts between these genomic regions. Cell division-related pathways were primarily affected by the enhancer deletions, which correlated with significant reduction in cell proliferation. Furthermore, we observed changes in angiogenesis-related genes consistent with the endothelial specificity of this SE. Indeed, deletion of the enhancers affected tube formation, resulting in reduced or shortened sprouts. The super-enhancer angiogenic role is at least partly due to its regulation of ADAMTS18, as siRNA knockdown of ADAMTS18 resulted in significantly shortened endothelial sprouts. Hence, functional characterization of a novel endothelial super-enhancer has revealed substantial downstream effects from single enhancer deletions and led to the discovery of the cis-target gene ADAMTS18 and its role in endothelial function.

Relationship between endothelial function and vascular stiffness on lower limit of cerebral autoregulation in patients undergoing cardiovascular surgery

Hemodynamic management based on cerebral autoregulation range is a possible strategy for preserving major organ perfusion during cardiovascular surgery. The purpose of this study was to evaluate the relation of vascular properties with lower limit of cerebral autoregulation (LLA). LLA was monitored in 66 patients undergoing cardiovascular surgery using near-infrared spectroscopy. To determine the clinical importance of LLA monitoring, association of blood pressure excursions below LLA and acute kidney injury (AKI) was evaluated. Flow-mediated dilation (FMD) and pulse wave velocity (PWV) were measured for the evaluation of endothelial function and aortic stiffness. Variables associated with LLA were evaluated. Excluding patients on hemodialysis, there were 15 patients (25.9%) who developed AKI. Blood pressure excursions below LLA were higher in patients who developed AKI (4.55 mm Hg × hr vs. 1.23 mm Hg × hr, P = .017). In the univariate analysis, prevalence of ischemic heart disease (No IHD: 53 ± 13.0 mm Hg vs. IHD: 60.0 ± 13.6 mm Hg, P = .056) and FMD (r = -0.42, 95% CI -0.61 to -0.19, P < .001) were associated with LLA before cardiopulmonary bypass (CPB). During CPB, calcium channel blocker (No Ca blocker: 42 ± 10.6 mm Hg vs. Ca blocker: 49 ± 14.3 mm Hg, P = .033), diabetes (no DM: 44 ± 13.2 mm Hg vs. DM: 55 ± 10.0 mm Hg, P = .024), FMD (r = -0.32, 95% CI -0.55 to -0.05, P = .021), and PWV (r = 0.28, 95% CI 0.012 to 0.513, P = .041) were associated with LLA. Multivariate analysis showed that FMD was correlated with LLA before CPB (r = -2.19, 95% CI -3.621 to -0.755, P = .003), while PWV was correlated with LLA during CPB (r = 0.01, 95% CI 0.001-0.019, P = .023). Endothelial function and aortic stiffness may be important factors in determining LLA at different phases in cardiovascular surgery.

Impact of COVID-19 on the Cardiovascular System: A Review of Available Reports

The recent emergence of the coronavirus disease 19 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in China is now a global health emergency. The transmission of SARS-CoV-2 is mainly via human-to-human contact. This virus is expected to be of zoonotic origin and has a high genome identity to that of bat derived SARS-like coronavirus. Various stringent measures have been implemented to lower person-to-person transmission of COVID-19. Particular observations and attempts have been made to reduce transmission in vulnerable populations, including older adults, children, and healthcare providers. This novel CoV enters the cells through the angiotensin-converting enzyme 2 (ACE2) receptor. There is a higher risk of COVID-19 infection among those with preexisting cardiovascular diseases (CVD), and it has been connected with various direct and indirect complications, including myocarditis, acute myocardial injury, venous thromboembolism, and arrhythmias. This article summarizes the various cardiovascular complications and mechanisms responsible for the same with COVID-19 infection. For the benefit of the scientific community and public, the effect of COVID-19 on major vital organs such as the kidneys, liver, and intestines has been briefly discussed. In this review, we also discuss drugs in different stages of clinical trials and their associated complications, as well as the details of vaccines in various stages of development.

Epigallocatechin gallate suppresses inflammation in human coronary artery endothelial cells by inhibiting NF-κB

The endothelium is a critical regulator of vascular homeostasis, controlling vascular tone and permeability as well as interactions of leukocytes and platelets with blood vessel walls. Consequently, endothelial dysfunction featuring inflammation and reduced vasodilation are considered central to cardiovascular disease (CVD) pathogenesis and have become a therapeutic area of focus. Type II endothelial cell (EC) activation by stress-related stimuli such as tumor necrosis factor-α (TNF-α) initiates the nuclear factor-κB (NF-κB) signaling pathway, a master regulator of inflammatory responses. Because dysregulated NF-κB signaling has been tightly linked to several CVDs, EC-specific inhibition of NF-κB represents an attractive pharmacological strategy. As accumulating evidence highlights the clinical benefits of tea catechin for multiple diseases including CVDs, we sought to determine whether the tea catechin epigallocatechin gallate (EGCG) that displays antioxidative, anti-inflammatory, hypolipidemic, anti-thrombogenic, and anti-hypertensive properties offers protection against CVDs by suppressing the canonical NF-κB pathway. Our findings indicate that EGCG downregulates multiple components of the TNF-α-induced NF-κB signaling pathway and thereby reduces the consequent increase in inflammatory gene transcription and protein expression. Furthermore, EGCG blocked type II EC activation, evidenced by diminished EC leakage and monocyte adhesion in EGCG-treated cells. In summary, our study advances knowledge of EGCG's anti-inflammatory effects on the NF-κB pathway and hence its benefits on endothelial health, supporting its therapeutic potential for CVDs.

Hypertension, Thrombosis, Kidney Failure, and Diabetes: Is COVID-19 an Endothelial Disease? A Comprehensive Evaluation of Clinical and Basic Evidence

The symptoms most commonly reported by patients affected by coronavirus disease (COVID-19) include cough, fever, and shortness of breath. However, other major events usually observed in COVID-19 patients (e.g., high blood pressure, arterial and venous thromboembolism, kidney disease, neurologic disorders, and diabetes mellitus) indicate that the virus is targeting the endothelium, one of the largest organs in the human body. Herein, we report a systematic and comprehensive evaluation of both clinical and preclinical evidence supporting the hypothesis that the endothelium is a key target organ in COVID-19, providing a mechanistic rationale behind its systemic manifestations.

COVID-19 and Stroke Risk: A Double Whammy

The emphasis so far during the COVID-19 pandemic has been on the respiratory manifestations with little attention being given to neurological manifestations. Literature has shown multiple cases of stroke being associated with COVID-19. Thus, there is great interest in the role of the virus in stroke pathogenesis. Regarding hyperacute and acute stroke treatment, the routine guidelines for thrombolysis and thrombectomy are to be followed with emphasis on high suspicion of COVID-19 in stroke cases with respiratory symptoms or with contact/travel history. Secondary risk factor treatment for hypertension, diabetes, dyslipidemia is a must. We recommend continuing angiotensin converting enzyme 2 inhibitors/angiotensin II receptor blockers (ARBs) in those who are taking these medications as per evidence available. Mandatory lockdown has led to delay in presentation to the hospital with a decrease in thrombolysis due to ineligibility and a corresponding increase in primary thrombectomies being performed. Telemedicine could be an important tool to triage cases worthy of tertiary referral from other strokes and must be encouraged.

Tadalafil may improve cerebral perfusion in small-vessel occlusion stroke-a pilot study

New treatments for cerebral small-vessel disease are needed to reduce the risk of small-vessel occlusion stroke and vascular cognitive impairment. We investigated an approach targeted to the signalling molecule cyclic guanosine monophosphate, using the phosphodiesterase 5 inhibitor tadalafil, to explore if it improves cerebral blood flow and endothelial function in patients with cerebral small-vessel disease and stroke. In a randomized, double-blinded, placebo-controlled, cross-over pilot trial (NCT02801032), we included patients who had a previous (>6 months) small-vessel occlusion stroke. They received a single dose of either 20 mg tadalafil or placebo on 2 separate days at least 1 week apart. We measured the following: baseline MRI for lesion load, repeated measurements of blood flow velocity in the middle cerebral artery by transcranial Doppler, blood oxygen saturation in the cortical microvasculature by near-infrared spectroscopy, peripheral endothelial response by EndoPAT and endothelial-specific blood biomarkers. Twenty patients with cerebral small-vessel disease stroke (3 women, 17 men), mean age 67.1 ± 9.6, were included. The baseline mean values ± standard deviations were as follows: blood flow velocity in the middle cerebral artery, 57.4 ± 10.8 cm/s; blood oxygen saturation in the cortical microvasculature, 67.0 ± 8.2%; systolic blood pressure, 145.8 ± 19.5 mmHg; and diastolic blood pressure, 81.3 ± 9.1 mmHg. We found that tadalafil significantly increased blood oxygen saturation in the cortical microvasculature at 180 min post-administration with a mean difference of 1.57 ± 3.02%. However, we saw no significant differences in transcranial Doppler measurements over time. Tadalafil had no effects on peripheral endothelial function assessed by EndoPAT and endothelial biomarker results conflicted. Our findings suggest that tadalafil may improve vascular parameters in patients with cerebral small-vessel disease stroke, although the effect size was small. Increased oxygenation of cerebral microvasculature during tadalafil treatment indicated improved perfusion in the cerebral microvasculature, theoretically presenting an attractive new therapeutic target in cerebral small-vessel disease. Future studies of the effect of long-term tadalafil treatment on cerebrovascular reactivity and endothelial function are needed to evaluate general microvascular changes and effects in cerebral small-vessel disease and stroke.

Protective Effects and Mechanisms of Vaccarin on Vascular Endothelial Dysfunction in Diabetic Angiopathy

Cardiovascular complications are a major leading cause of mortality in patients suffering from type 2 diabetes mellitus (T2DM). Vascular endothelial dysfunction is a core pathophysiological event in the early stage of T2DM and eventually leads to cardiovascular disease. Vaccarin (VAC), an active flavonoid glycoside extracted from vaccariae semen, exhibits extensive biological activities including vascular endothelial cell protection effects. However, little is known about whether VAC is involved in endothelial dysfunction regulation under high glucose (HG) or hyperglycemia conditions. Here, in an in vivo study, we found that VAC attenuated increased blood glucose, increased glucose and insulin tolerance, relieved the disorder of lipid metabolism and oxidative stress, and improved endothelium-dependent vasorelaxation in STZ/HFD-induced T2DM mice. Furthermore, in cultured human microvascular endothelial cell-1 (HMEC-1) cells, we showed that pretreatment with VAC dose-dependently increased nitric oxide (NO) generation and the phosphorylation of eNOS under HG conditions. Mechanistically, VAC-treated HMEC-1 cells exhibited higher AMPK phosphorylation, which was attenuated by HG stimulation. Moreover, HG-triggered miRNA-34a upregulation was inhibited by VAC pretreatment, which is in accordance with pretreatment with AMPK inhibitor compound C (CC). In addition, both reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) and VAC abolished HG-evoked dephosphorylation of AMPK and eNOS, increased miRNA-34a expression, and decreased NO production. These results suggest that VAC impedes HG-induced endothelial dysfunction via inhibition of the ROS/AMPK/miRNA-34a/eNOS signaling cascade.

Home-based aerobic exercise in patients with lacunar stroke: Design of the HITPALS randomized controlled trial

Background

The effects of physical exercise in patients with lacunar stroke, seem promising in secondary prevention and only few studies have investigated the effect of high-intensity interval training in patients with lacunar stroke. This study will be investigating whether high-intensity interval training improves cardiovascular fitness as well as cognitive- and endothelial function and potentially attenuating the risk of recurrent stroke.

Methods

A randomized controlled trial evaluating 12 weeks of home-based, high-intensity interval training compared with usual care. The intervention group will be exercising 15 min a day, 5 days a week, for 12 weeks. Outcomes will be evaluated at baseline, three, six and twelve months post-stroke with ‘The Graded Cycling Test with Talk Test’ as the primary outcome registered as power output in Watts. Additionally, an annually register-based follow-up will be performed for 5 years from date of inclusion with a composite endpoint of cardiovascular disease or death. Secondary outcomes will be: physical activity, endothelial response, mental well-being, cognition, mood, fatigue, stress, and MRI scan.

Discussion

This study is going to show if early initiated home-based high-intensity interval training is feasible and effective in patients with lacunar stroke. A self-chosen aerobic exercise modality allows a realistic implementation of practice, together with greater chance of long-term adherence. A limitation of the study is that recruitment bias cannot be ruled out, as there may be a preferential enrolment of patients who are self-motivated to engage in exercise.

Endothelial Function in COPD Is in an Intermediate Position Between Healthy Subjects and Coronary Artery Disease Patients and Is Related to Physical Activity

Patients with chronic obstructive pulmonary disease (COPD) have an increased risk of ischemic heart disease. Endothelial dysfunction may play a role in the onset of cardiovascular event. Previous studies showed an impaired endothelial function (measured by flow-mediated dilation, FMD) in COPD patients compared to healthy subjects. To the best of our knowledge no study has compared FMD in COPD and in cardiac (coronary artery disease, CAD) patients. We aimed to assess FMD in healthy subjects, COPD, CAD, and COPD + CAD. The main result is that FMD in COPD is reduced and is in an intermediate position between healthy subjects and CAD or COPD + CAD; this impairment can contribute to explain the higher prevalence of cardiovascular disease in COPD. The only determinant independently associated with FMD in all subjects is the physical activity level, irrespective of the traditional risk factors (i.e., smoke, dyslipidemia, hypertension).

Endothelial cells: source, barrier, and target of defensive mediators

Endothelium is strategically located at the interface between blood and interstitial tissues, placing thus endothelial cell as a key player in vascular homeostasis. Endothelial cells are in a dynamic equilibrium with their environment and constitute concomitantly a source, a barrier, and a target of defensive mediators. This review will discuss the recent advances in our understanding of the complex crosstalk between the endothelium, the complement system and the hemostasis in health and in disease. The first part will provide a general introduction on endothelial cells heterogeneity and on the physiologic role of the complement and hemostatic systems. The second part will analyze the interplay between complement, hemostasis and endothelial cells in physiological conditions and their alterations in diseases. Particular focus will be made on the prototypes of thrombotic microangiopathic disorders, resulting from complement or hemostasis dysregulation-mediated endothelial damage: atypical hemolytic uremic syndrome and thrombotic thrombocytopenic purpura. Novel aspects of the pathophysiology of the thrombotic microangiopathies will be discussed.

Vascular senescence and ageing: a role for the MEOX proteins in promoting endothelial dysfunction

In the vascular system, ageing is accompanied by the accrual of senescent cells and is associated with an increased risk of vascular disease. Endothelial cell (EC) dysfunction is a hallmark of vascular disease and is characterized by decreased angiogenic potential, reduced nitric oxide bioavailability, impaired vasodilation, increased production of ROS, and enhanced inflammation. In ECs, the major producer of nitric oxide is the endothelial nitric oxide synthase (eNOS) enzyme that is encoded by the NOS3 gene. NOS3/eNOS function is tightly regulated at both the transcriptional and post-transcriptional levels to maintain normal vascular function. A key transcriptional regulator of eNOS expression is p53, which has been shown to play a central role in mediating cellular senescence and thereby vascular dysfunction. Herein, we show that, in ECs, the MEOX homeodomain transcription factors decrease the expression of genes involved in angiogenesis, repress eNOS expression at the mRNA and protein levels, and increase the expression of p53. These findings support a role for the MEOX proteins in promoting endothelial dysfunction.

All muscarinic acetylcholine receptors (M1-M5) are expressed in murine brain microvascular endothelium

Clinical and experimental studies indicate that muscarinic acetylcholine receptors are potential pharmacological targets for the treatment of neurological diseases. Although these receptors have been described in human, bovine and rat cerebral microvascular tissue, a subtype functional characterization in mouse brain endothelium is lacking. Here, we show that all muscarinic acetylcholine receptors (M₁-M₅) are expressed in mouse brain microvascular endothelial cells. The mRNA expression of M₂, M₃, and M₅ correlates with their respective protein abundance, but a mismatch exists for M₁ and M₄ mRNA versus protein levels. Acetylcholine activates calcium transients in brain endothelium via muscarinic, but not nicotinic, receptors. Moreover, although M₁ and M₃ are the most abundant receptors, only a small fraction of M₁ is present in the plasma membrane and functions in ACh-induced Ca²⁺ signaling. Bioinformatic analyses performed on eukaryotic muscarinic receptors demonstrate a high degree of conservation of the orthosteric binding site and a great variability of the allosteric site. In line with previous studies, this result indicates muscarinic acetylcholine receptors as potential pharmacological targets in future translational studies. We argue that research on drug development should especially focus on the allosteric binding sites of the M₁ and M₃ receptors.

Maintenance of negative fluid balance can improve endothelial and cardiac functions in primary hypertensive patients

PURPOSE

The issue of unidentified volume expansion is well recognized as a cause for resistance to antihypertensive therapy. The aim of study is to identify contribution of negative fluid balance to hypertension control and impact on endothelial and cardiac functions among primary hypertensive patients who do not have kidney failure.

MATERIALS AND METHODS

This is a prospective interventional study with one-year follow-up. Preceded by volume status measurements were performed by a body composition monitor (BCM), the patients were put on ambulatory blood pressure monitoring for 24 hours. Then, echocardiographic assessments and flow-mediated dilation (FMD) and carotid intima-media thickness (CIMT) measurements were completed. Patients in one of the two groups were kept negative hydrated during trial with diuretic treatment.

RESULTS

At the end of one-year follow-up, patients in negative hydrated group were found to have significantly lower CIMT, left ventricle mass index, left ventricular end-diastolic diameter, mean systolic and diastolic BP, non-dipper patient ratio, and higher FMD. In negatively hydrated group, target organ damage significantly reduced during trial.

CONCLUSIONS

The significance of negative hydration status with respect to blood pressure control, endothelial and cardiac functions within primary hypertensive patients who do not suffer from kidney failure has been demonstrated.

Correlation Between Flow-Mediated Dilatation of the Brachial Artery and Serum Endothelial Biomarkers in the Evaluation of Acute Endothelial Injury After Cardiopulmonary Bypass

OBJECTIVES

The purpose of this study was to investigate the correlation between flow-mediated dilatation of the brachial artery and serum endothelial biomarkers and to discuss the feasibility of sonographic evaluation of acute endothelial injury during cardiopulmonary bypass (CPB) surgery.

METHODS

Sonography was applied to determine the percentage of change in the brachial artery size during flow-mediated dilatation. Meanwhile, the plasma concentrations of endothelial-derived biomarkers, such as endothelin 1, nitric oxide, and von Willebrand factor, were measured to monitor the changes in endothelial function. We analyzed the correlation between flow-mediated dilatation and biomarkers during the perioperative period of CPB in 27 patients.

RESULTS

All of the biomarkers changed dramatically, especially during the CPB period. There was a negative correlation between flow-mediated dilatation and von Willebrand factor (P = .001; R = -0.31).

CONCLUSIONS

A CPB event has a substantial impact on endothelial function, and sonographic assessment of the percentage of change in the brachial artery size during flow-mediated dilatation allows early detection of acute endothelial function injury in cardiac surgery.

Insulin resistance: potential role of the endogenous nitric oxide synthase inhibitor ADMA

The insulin resistance syndrome (IRS) is considered to be a new target of risk-reduction therapy. The IRS is a cluster of closely associated and interdependent abnormalities and clinical outcomes that occur more commonly in insulin-resistant/hyperinsulinemic individuals. This syndrome predisposes individuals to type 2 diabetes, cardiovascular diseases, essential hypertension, certain forms of cancer, polycystic ovary syndrome, nonalcoholic fatty liver disease, and sleep apnea. In patients at high risk for cardiovascular diseases, endothelial dysfunction is observed in morphologically intact vessels even before the onset of clinically manifest vascular disease. Indeed, there are several lines of evidence that indicate that endothelial function is compromised in situations where there is reduced sensitivity to endogenous insulin. It is well established that a decreased bioavailability of nitric oxide (NO) contributes to endothelial dysfunction. Furthermore, NO may modulate insulin sensitivity. Activation of NO synthase (NOS) augments blood flow to insulin-sensitive tissues (i.e. skeletal muscle, liver, adipose tissue), and its activity is impaired in insulin resistance. Inhibition of NOS reduces the microvascular delivery of nutrients and blunts insulin-stimulated glucose uptake in skeletal muscle. Furthermore, induction of hypertension by administration of the NOS inhibitor NG-monomethyl-L-arginine is also associated with insulin resistance in rats. Increased levels of asymmetric dimethylarginine (ADMA) are associated with endothelial vasodilator dysfunction and increased risk of cardiovascular diseases. An intriguing relationship exists between insulin resistance and ADMA. Plasma levels of ADMA are positively correlated with insulin resistance in nondiabetic, normotensive people. New basic research insights that provide possible mechanisms underlying the development of insulin resistance in the setting of impaired NO bioavailability will be discussed.

P-Selectin Targeted Dexamethasone-Loaded Lipid Nanoemulsions: A Novel Therapy to Reduce Vascular Inflammation

Inflammation is a common process associated with numerous vascular pathologies. We hypothesized that targeting the inflamed endothelium by coupling a peptide with high affinity for P-selectin to the surface of dexamethasone-loaded lipid nanoemulsions will highly increase their specific binding to activated endothelial cells (EC) and reduce the cell activation. We developed and characterized dexamethasone-loaded lipid nanoemulsions directed towards P-selectin (PLN-Dex) and monitored their anti-inflammatory effects in vitro using cultured EC (EA.hy926 cells) and in vivo using a mouse model of acute inflammation [lipopolysaccharides (LPS) intravenously administered in C57BL/6 mice]. We found that PLN-Dex bound specifically to the surface of activated EC are efficiently internalized by EC and reduced the expression of proinflammatory genes, thus preventing the monocyte adhesion and transmigration to/through activated EC. Given intravenously in mice with acute inflammation, PLN-Dex accumulated at a significant high level in the lungs (compared to nontargeted nanoemulsions) and significantly reduced mRNA expression level of key proinflammatory cytokines such as IL-1β, IL-6, and MCP-1. In conclusion, the newly developed nanoformulation, PLN-Dex, is functional in vitro and in vivo, reducing selectively the endothelium activation and the consequent monocyte infiltration and diminishing significantly the lungs' inflammation, in a mouse model of acute inflammation.

Isoflavones improve vascular reactivity in post-menopausal women with hypercholesterolemia

This randomized clinical trial was designed to assess the effects of dietary isoflavones on vascular reactivity, lipid levels, and markers of inflammation in post-menopausal women. Epidemiological studies have revealed that populations consuming large amounts of soy protein have lower cardiovascular morbidity and mortality. The benefits of soy protein may be due to its hypolipidemic effects; its anti-oxidant properties; its high content of L-arginine; and=or or its phytoestrogen content. Two putative mediators of the effects of soy protein are the isoflavones genistein and daidzein. Forty post-menopausal, hypercholesterolemic women who did not take estrogen replacement therapy were recruited for this study of isoflavone supplementation. Baseline flow-mediated vasodilation and response to nitroglycerin were measured, along with urinary isoflavone and nitrite=nitrate levels and serum lipids. After 6 weeks of 90 mg of isoflavones daily versus placebo, women receiving isoflavones demonstrated improved responsiveness to nitroglycerin, an assessment of endothelium-independent vasodilation, with an effect size (percentage points change from baseline) of 7.2 1.9 versus 1.2 1.3; p = 0.01. There was a trend towards improvement of flow-mediated vasodilation, which is an endothelium-dependent response (effect size: 3.4 2.0% versus -0.6 1.7%; p = 0.12). Lipid levels were unchanged after isoflavone treatment. In conclusion, dietary isoflavones may have cardiovascular benefit in the form of improved vascular reactivity, but not by lowering cholesterol, for women who do not take estrogen replacement therapy.

Advanced glycation end products upregulate lysyl oxidase and endothelin-1 in human aortic endothelial cells via parallel activation of ERK1/2-NF-κB and JNK-AP-1 signaling pathways

Endothelial dysfunction involves deregulation of the key extracellular matrix (ECM) enzyme lysyl oxidase (LOX) and the vasoconstrictor protein, endothelin-1 (ET-1), whose gene expression can be modulated by the transcriptional activators nuclear factor kappa B (NF-κB) and activator protein-1 (AP-1). Advanced glycation end products (AGEs) present an aggravating factor of endothelial dysfunction which upon engagement to their receptor RAGE induce upregulation of mitogen-activated protein kinases (MAPKs), leading to NF-κB and AP-1 potentiation. We hypothesized that AGEs could induce NF-κΒ- and AP-1-dependent regulation of LOX and ET-1 expression via the AGE/RAGE/MAPK signaling axis. Western blot, real-time qRT-PCR, FACS analysis and electrophoretic mobility-shift assays were employed in human aortic endothelial cells (HAECs) following treatment with AGE-bovine serum albumin (AGE-BSA) to investigate the signaling pathway towards this hypothesis. Furthermore, immunohistochemical analysis of AGEs, RAGE, LOX and ET-1 expression was conducted in aortic endothelium of a rat experimental model exposed to high- or low-AGE content diet. HAECs exposed to AGE-BSA for various time points exhibited upregulation of LOX and ET-1 mRNA levels in a dose- and time-dependent manner. Exposure of HAECs to AGE-BSA also showed specific elevation of phospho(p)-ERK1/2 and p-JNK levels in a dose- and time-dependent fashion. AGE administration significantly increased NF-κΒ- and AP-1-binding activity to both LOX and ET-1 cognate promoter regions. Moreover, LOX and ET-1 overexpression in rat aortic endothelium upon high-AGE content diet confirmed the functional interrelation of these molecules. Our findings demonstrate that AGEs trigger NF-κΒ- and AP-1-mediated upregulation of LOX and ET-1 via the AGE/RAGE/MAPK signaling cascade in human endothelial cells, thus contributing to distorted endothelial homeostasis by impairing endothelial barrier function, altering ECM biomechanical properties and cell proliferation.

Drug Resistance of Endocardial Endothelial Cells is Related to Higher Endogenous ABCG2

Endocardial endothelial cells (EECs), when compared with endothelial cells of arteries and veins, possess higher resistance to apoptosis-inducing anticancer agents. The mechanism of this resistance property is unknown. We have investigated the molecular mechanism, which contributes to increased cell survival capacity in EECs. We explored whether the resistance to apoptosis is associated with the cellular expression of ATP-binding cassette transporters such as P-glycoprotein, MRP-1, and ABCG2. We used primary and immortalized porcine endocardial endothelial cells (PEECs and hTERT PEECs) and compared the results with that in porcine aortic endothelial cells (PAECs), left atrioventricular valve endothelial cells (PVECs), and human umbilical vein endothelial cell line (EA.hy926). FACS and immunoblot analysis revealed a significantly higher expression of ABCG2 in PEECs and hTERT PEECs compared to PAECs, PVECs, and EA.hy926. Using apoptosis-inducing anticancer agents such as doxorubicin and camptothecin, through chromatin condensation assay and immunoblot analysis, we demonstrated a higher resistance to apoptosis in EECs compared to PAECs, PVECs, and EA.hy926. Interestingly, resistance in EECs reversed in presence of ABCG2 specific inhibitor, fumitremorgin C. Our observations suggest that an inherently high expression of ABCG2 in EECs protects them against apoptosis in presence of anticancer agents.

Modulating DDAH/NOS Pathway to Discover Vasoprotective Insulin Sensitizers

Insulin resistance syndrome (IRS) is a configuration of cardiovascular risk factors involved in the development of metabolic disorders including type 2 diabetes mellitus. In addition to diet, age, socioeconomic, and environmental factors, genetic factors that impair insulin signaling are centrally involved in the development and exacerbation of IRS. Genetic and pharmacological studies have demonstrated that the nitric oxide (NO) synthase (NOS) genes are critically involved in the regulation of insulin-mediated glucose disposal. The generation of NO by the NOS enzymes is known to contribute to vascular homeostasis including insulin-mediated skeletal muscle vasodilation and insulin sensitivity. By contrast, excessive inhibition of NOS enzymes by exogenous or endogenous factors is associated with insulin resistance (IR). Asymmetric dimethylarginine (ADMA) is an endogenous molecule that competitively inhibits all the NOS enzymes and contributes to metabolic perturbations including IR. The concentration of ADMA in plasma and tissue is enzymatically regulated by dimethylarginine dimethylaminohydrolase (DDAH), a widely expressed enzyme in the cardiovascular system. In preclinical studies, overexpression of DDAH has been shown to reduce ADMA levels, improve vascular compliance, and increase insulin sensitivity. This review discusses the feasibility of the NOS/DDAH pathway as a novel target to develop vasoprotective insulin sensitizers.

Natriuretic peptides and cardio-renal disease

The natriuretic peptide (NP) system is an important endocrine, autocrine and paracrine system, consisting of a family of peptides which provide cardiac, renal and vascular effects that, through their beneficial physiological actions, play a key role in maintaining overall cardiovascular health. Traditionally, the pathophysiological origins of cardio-renal disease have been viewed as the domain of the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system (SNS), with inappropriate activation of both systems leading to deleterious changes in cardio-renal function and structure. Therapies designed to suppress the RAAS and the SNS have been routinely employed to address the consequences of cardio-renal disease. However, it is now becoming increasingly apparent that enhancing the beneficial physiological effects of the NP system may represent an attractive alternative therapeutic approach to counter the pathophysiological effects of disease. In particular, innovative therapeutic strategies aimed at enhancing the physiological benefits afforded by NPs while simultaneously suppressing the RAAS are generating increasing interest as potential treatment options for the management of cardio-renal disease.

Aortic valve sclerosis in mice deficient in endothelial nitric oxide synthase

Risk factors for fibrocalcific aortic valve disease (FCAVD) are associated with systemic decreases in bioavailability of endothelium-derived nitric oxide (EDNO). In patients with bicuspid aortic valve (BAV), vascular expression of endothelial nitric oxide synthase (eNOS) is decreased, and eNOS(-/-) mice have increased prevalence of BAV. The goal of this study was to test the hypotheses that EDNO attenuates profibrotic actions of valve interstitial cells (VICs) in vitro and that EDNO deficiency accelerates development of FCAVD in vivo. As a result of the study, coculture of VICs with aortic valve endothelial cells (vlvECs) significantly decreased VIC activation, a critical early phase of FCAVD. Inhibition of VIC activation by vlvECs was attenuated by N(G)-nitro-l-arginine methyl ester or indomethacin. Coculture with vlvECs attenuated VIC expression of matrix metalloproteinase-9, which depended on stiffness of the culture matrix. Coculture with vlvECs preferentially inhibited collagen-3, compared with collagen-1, gene expression. BAV occurred in 30% of eNOS(-/-) mice. At age 6 mo, collagen was increased in both bicuspid and trileaflet eNOS(-/-) aortic valves, compared with wild-type valves. At 18 mo, total collagen was similar in eNOS(-/-) and wild-type mice, but collagen-3 was preferentially increased in eNOS(-/-) mice. Calcification and apoptosis were significantly increased in BAV of eNOS(-/-) mice at ages 6 and 18 mo. Remarkably, these histological changes were not accompanied by physiologically significant valve stenosis or regurgitation. In conclusion, coculture with vlvECs inhibits specific profibrotic VIC processes. In vivo, eNOS deficiency produces fibrosis in both trileaflet and BAVs but produces calcification only in BAVs.

Effects of red wine on established markers of arterial structure and function in human studies: current knowledge and future research directions

Evidence from observational studies suggests that mild-to-moderate consumption of red wine is associated with reduced cardiovascular morbidity and mortality. Various individual chemical components of red wine also show salutary effects on vascular homeostasis, that is, enhanced endothelial function and arterial distensibility, both in vitro and in animal studies. However, testing the beneficial potential of red wine in primary and secondary cardiovascular prevention on established surrogate cardiovascular markers requires further study with longer term intervention trials. This report reviews and critically appraises the published evidence for the effects of red wine on endothelium-dependent vasodilation, arterial stiffness and arterial wave reflections in healthy subjects and in patients with cardiovascular disease. Suggestions for future research directions are also provided.

Effects of Pioglitazone on Asymmetric Dimethylarginine and Components of the Metabolic Syndrome in Nondiabetic Patients (EPICAMP Study): A Double-Blind, Randomized Clinical Trial

The present trial aimed to investigate the effects of pioglitazone on the serum level of asymmetric dimethylarginine (ADMA), a marker of endothelial function, and some indices of inflammation and glucose and lipid metabolism in nondiabetic metabolic syndrome patients. 104 eligible participants (57% female; age between 20 and 70) were enrolled in a double-blind placebo-controlled trial and were randomized to receive either pioglitazone (uptitrated to 30 mg/day) or matching placebo for 24 weeks. Participants were clinically examined and a blood sample was obtained at baseline and at the end of the trial. Pioglitazone significantly improved C-reactive protein level irrespective of changes in insulin sensitivity. Compared with the placebo group, alanine and aspartate transaminases were decreased and high-density lipoprotein cholesterol was increased after treatment with pioglitazone. A considerably greater weight gain was also recorded in the intervention group. We failed to observe any significant changes in serum ADMA in either group and between groups with and without adjustment for age, sex, and components of the metabolic syndrome. In a nutshell, pioglitazone seems to have positive effects on lipid profile, liver transaminases, and systemic inflammation. However, its previously demonstrated endothelial function-improving properties do not seem to be mediated by ADMA.

FXR agonist INT-747 upregulates DDAH expression and enhances insulin sensitivity in high-salt fed Dahl rats

Aims

Genetic and pharmacological studies have shown that impairment of the nitric oxide (NO) synthase (NOS) pathway is associated with hypertension and insulin-resistance (IR). In addition, inhibition of NOS by the endogenous inhibitor, asymmetric dimethylarginine (ADMA), may also result in hypertension and IR. On the other hand, overexpression of dimethylarginine dimethylaminohydrolase (DDAH), an enzyme that metabolizes ADMA, in mice is associated with lower ADMA, increased NO and enhanced insulin sensitivity. Since DDAH carries a farnesoid X receptor (FXR)-responsive element, we aimed to upregulate its expression by an FXR-agonist, INT-747, and evaluate its effect on blood pressure and insulin sensitivity.

Methods and Results

In this study, we evaluated the in vivo effect of INT-747 on tissue DDAH expression and insulin sensitivity in the Dahl rat model of salt-sensitive hypertension and IR (Dahl-SS). Our data indicates that high salt (HS) diet significantly increased systemic blood pressure. In addition, HS diet downregulated tissue DDAH expression while INT-747 protected the loss in DDAH expression and enhanced insulin sensitivity compared to vehicle controls.

Conclusion

Our study may provide the basis for a new therapeutic approach for IR by modulating DDAH expression and/or activity using small molecules.

Endothelial cells derived from nuclear reprogramming

The endothelium plays a pivotal role in vascular homeostasis, regulating the tone of the vascular wall, and its interaction with circulating blood elements. Alterations in endothelial functions facilitate the infiltration of inflammatory cells and permit vascular smooth muscle proliferation and platelet aggregation. Therefore, endothelial dysfunction is an early event in disease processes including atherosclerosis, and because of its critical role in vascular health, the endothelium is worthy of the intense focus it has received. However, there are limitations to studying human endothelial function in vivo, or human vascular segments ex vivo. Thus, methods for endothelial cell (EC) culture have been developed and refined. Recently, methods to derive ECs from pluripotent cells have extended the scientific range of human EC studies. Pluripotent stem cells may be generated, expanded, and then differentiated into ECs for in vitro studies. Constructs for molecular imaging can also be employed to facilitate tracking these cells in vivo. Furthermore, one can generate patient-specific ECs to study the effects of genetic or epigenetic alterations on endothelial behavior. Finally, there is the opportunity to apply these cells for vascular therapy. This review focuses on the generation of ECs from stem cells; their characterization by genetic, histological, and functional studies; and their translational applications.

Variação do diâmetro da artéria braquial em crianças obesas: presente e futuro

OBJETIVO: Revisão da literatura acerca do uso da medida da variação do diâmetro da artéria braquial por ultrassonografia de alta resolução (dilatação mediada por fluxo) como preditor de risco para doença cardiovascular em crianças e adolescentes obesos. FONTES DE DADOS: Levantamento de publicações indexadas no Medline/PubMed de trabalhos publicados entre 2002 e 2011, rastreadas com a combinação dos descritores: "endothelium", "child", "ultrasonography" e "obesity", além de estudos e textos clássicos sobre o tema. Foram encontradas 54 publicações e 32 delas foram incluídas na presente revisão do tema. SINTESE DOS DADOS: O estudo da disfunção endotelial tem sido empregado como preditor de risco para doenças cardiovasculares, tais como aterosclerose e doença cardíaca coronariana, visto que a lesão endotelial é um importante evento na fisiopatologia de tais doenças. CONCLUSÕES: A dilatação mediada por fluxo da artéria braquial mostra-se importante como ferramenta diagnóstica e prognóstica na avaliação da função endotelial de crianças e adolescentes com excesso de peso por ser um método não invasivo, com boa aplicabilidade quanto ao custo, à inocuidade e ao benefício.

A procyanidin trimer, C1, promotes NO production in rat aortic endothelial cells via both hyperpolarization and PI3K/Akt pathways

Procyanidins, which are condensed catechins, have been elucidated as absorbable polyphenols, but their health-benefits remain unclear. The aim of this study was, thus, to clarify the efficacy and mechanism of each procyanidin oligomer in NO activation in rat aortic endothelial cells (RAECs). Treatment of RAECs with 50μM procyanidin C1 (4β→8 trimer) resulted in a time- and dose-dependent hyperpolarization using the membrane potential-sensitive probe bis-(1,3-dibutylbarbituric acid) trimethine oxonol, while no effect was observed for (-)-epicatechin (a monomer) and procyanidin B2 (4β→8 dimer). The C1-induced hyperpolarization was inhibited by iberiotoxin, a specific inhibitor of large-conductance Ca(2+)-activated K(+) (BK(Ca)) channel, as well as 2-aminoethyl diphenylborinate (2-APB), a store-operated Ca(2+) entry inhibitor. Procyanidin C1 caused a significant increase in NO production from RAECs via phosphorylation of both eNOS and Akt, and the effect was completely inhibited by N(G)-monomethyl-l-arginine or combined treatment with iberiotoxin and the phosphatidylinositol 3-kinase (PI3K) specific inhibitor, wortmannin, as well as combined treatment with 2-APB and wortmannin. Taken together, these findings provide critical evidence that procyanidin C1, but not B2, has potential to induce NO production in RAECs via both Ca(2+)-dependent BK(Ca) channel-mediated hyperpolarization and Ca(2+)-independent PI3K/Akt pathways.

Periodontal disease and atherosclerotic vascular disease: does the evidence support an independent association?: a scientific statement from the American Heart Association

A link between oral health and cardiovascular disease has been proposed for more than a century. Recently, concern about possible links between periodontal disease (PD) and atherosclerotic vascular disease (ASVD) has intensified and is driving an active field of investigation into possible association and causality. The 2 disorders share several common risk factors, including cigarette smoking, age, and diabetes mellitus. Patients and providers are increasingly presented with claims that PD treatment strategies offer ASVD protection; these claims are often endorsed by professional and industrial stakeholders. The focus of this review is to assess whether available data support an independent association between ASVD and PD and whether PD treatment might modify ASVD risks or outcomes. It also presents mechanistic details of both PD and ASVD relevant to this topic. The correlation of PD with ASVD outcomes and surrogate markers is discussed, as well as the correlation of response to PD therapy with ASVD event rates. Methodological issues that complicate studies of this association are outlined, with an emphasis on the terms and metrics that would be applicable in future studies. Observational studies to date support an association between PD and ASVD independent of known confounders. They do not, however, support a causative relationship. Although periodontal interventions result in a reduction in systemic inflammation and endothelial dysfunction in short-term studies, there is no evidence that they prevent ASVD or modify its outcomes.

The ADMA-Metformin Hypothesis: Linking the Cardiovascular Consequences of the Metabolic Syndrome and Type 2 Diabetes

Metformin and asymmetric dimethylarginine (ADMA) are structural analogs. They have opposite effects at multiple points on complex signaling pathways that coordinate energy, molecular synthesis, growth, and metabolism with nutrient intake. Excess saturated fats and glucose may initiate the methylation of arginine residues in proteins involved in the transcription of genes mediating inflammation, cell proliferation, apoptosis, and oncogenesis. Free ADMA may appear in the circulation after proteolysis of these proteins when the work of transcription is complete and ADMA subsequently functions as a signaling molecule. In children, ADMA levels are not significantly related to the usual metabolic syndrome risk factors but instead there is a significant association between ADMA and alkaline phosphatase - a marker of normal growth. There is only one direct study that shows that ADMA negates the metabolic effects of metformin. There are no investigations that demonstrate that metformin blocks the effect of ADMA and so this review must be considered hypothesis generating. The potential implications of the metformin-ADMA relationship merit further investigation.

Aging and vascular endothelial function in humans

Advancing age is the major risk factor for the development of CVD (cardiovascular diseases). This is attributable, in part, to the development of vascular endothelial dysfunction, as indicated by reduced peripheral artery EDD (endothelium-dependent dilation) in response to chemical [typically ACh (acetylcholine)] or mechanical (intravascular shear) stimuli. Reduced bioavailability of the endothelium-synthesized dilating molecule NO (nitric oxide) as a result of oxidative stress is the key mechanism mediating reduced EDD with aging. Vascular oxidative stress increases with age as a consequence of greater production of reactive oxygen species (e.g. superoxide) without a compensatory increase in antioxidant defences. Sources of increased superoxide production include up-regulation of the oxidant enzyme NADPH oxidase, uncoupling of the normally NO-producing enzyme, eNOS (endothelial NO synthase) (due to reduced availability of the cofactor tetrahydrobiopterin) and increased mitochondrial synthesis during oxidative phosphorylation. Increased bioactivity of the potent endothelial-derived constricting factor ET-1 (endothelin-1), reduced endothelial production of/responsiveness to dilatory prostaglandins, the development of vascular inflammation, formation of AGEs (advanced glycation end-products), an increased rate of endothelial apoptosis and reduced expression of oestrogen receptor α (in postmenopausal females) also probably contribute to impaired EDD with aging. Several lifestyle and biological factors modulate vascular endothelial function with aging, including regular aerobic exercise, dietary factors (e.g. processed compared with non-processed foods), body weight/fatness, vitamin D status, menopause/oestrogen deficiency and a number of conventional and non-conventional risk factors for CVD. Given the number of older adults now and in the future, more information is needed on effective strategies for the prevention and treatment of vascular endothelial aging.

Gender-based cardiometabolic risk evaluation in minority and non-minority men grading the evidence of non-traditional determinants of cardiovascular risk

Evaluation of cardiometabolic risk has become vital in primary prevention of adverse vascular events (coronary artery disease, heart attack, stroke or congestive heart failure), particularly in younger middle-aged men (40-60 years old). To discern the prevalence of events in these men, clinicians often stratify cardiovascular risk and treat according to traditional Framingham risk criteria. Yet it is evident that the traditional Framingham risk assigned to intermediate- and low-risk men will miss several of these individuals deemed at high 'cardiometabolic risk', also known as residual cardiovascular risk. This review will elaborate the definition of cardiometabolic risk and apply the use of surrogate markers for cardiovascular risk stratification in men in addition to the traditional Framingham-based markers. It will utilise both gender non-specific and gender-specific determinants of cardiometabolic risk. Lastly, it will examine minority men's health and racial differences in these determinants of cardiovascular risk. This analysis includes an electronic literature search utilising PubMed, EMBASE and MEDLINE databases to clarify the level of evidence for the stepwise utility of novel biomarkers for cardiometabolic risk in the male patient. This manuscript generates discussion of the utility of markers of cardiometabolic risk stratification. The following questions are summarised: (i) Are there non-traditional tests that might define this risk better than traditional markers? (ii) Will treatment based on this risk assessment augment present risk stratification and lower cardiovascular risk? (iii) What is known regarding racial differences surrounding cardiometabolic risk assessment? Traditional risk factors including Framingham Risk Score underestimate the overall 10 year and lifetime risk for the intermediate-risk younger middle-aged men<60 years of age. This fact is especially true in the minority population. We have graded the evidence of non-gender specific and gender-specific markers of cardiometabolic risk, thereby, allowing greater clarification of risk in this population. The pragmatic use of these novel markers of cardiometabolic risk may help stratify those individuals at greater lifetime risk than that noted by the Framingham Risk Score.

Plasma matrix metalloproteinase (MMP)-9 levels are reduced following low-calorie cranberry juice supplementation in men

OBJECTIVE

Matrix metalloproteinase (MMP)-9, also known as gelatinase B, is implicated in the development of hypertension and atherosclerotic plaque vulnerability to rupture, an important step in the etiology of cardiovascular diseases. Studies have suggested that flavonoid consumption may be cardioprotective, and its favorable impact on circulating MMP-9 concentrations could partly explain this association. The aim of the present study was to determine the effect of consuming increasing daily doses of low-calorie cranberry juice cocktail (CJC) on plasma MMP-9 concentrations of abdominally obese men.

METHODS

Thirty men (mean age +/- SD: 51 +/- 10 years) consumed increasing doses of CJC during 3 successive periods of 4 weeks (weeks 1-4: 125 ml/day, weeks 5-8: 250 ml/day, and weeks 9-12: 500 ml/day). Before the study and after each phase, a series of physical and metabolic variables were measured, including MMP-9.

RESULTS

We found that CJC supplementation significantly decreased plasma MMP-9 concentrations (mean +/- SEM: -36% +/- 9%, p < 0.0005; week 12 vs. baseline) while baseline plasma MMP-9 concentrations strongly correlated with the changes noted over the entire intervention (r = -0.71, p < 0.0001). We also show that the reduction in plasma MMP-9 levels was associated with a change in plasma nitrites/nitrates (NOx) concentration over the entire intervention (r = -0.38, p < 0.05; week 12 vs. baseline). Significant correlations were also noted between changes in plasma MMP-9 levels and those of systolic (r = 0.39, p < 0.05) and diastolic (r = 0.60, p < 0.001) blood pressure during the course of the study (week 12 vs. baseline).

CONCLUSIONS

Our results show that daily CJC consumption is associated with a decrease in plasma MMP-9 concentrations in abdominally obese men. We hypothesize that polyphenolic compounds from cranberries may be responsible for this effect, supporting the notion that the consumption of flavonoid-rich foods can exert cardioprotective effects.