Therapeutic approach in the improvement of endothelial dysfunction: the current state of the art

Microfluidic artery-on-a-chip model with unidirectional gravity-driven flow for high-throughput applications

Cardiovascular disease (CVD) is the leading cause of death worldwide, with a noticeable decline in the approval of new therapeutic interventions. Currently, there is no gold standard for developing new therapies for CVDs, and preclinical models do not translate to clinical efficacy. Therefore, there is an urgent need for in vitro models that more accurately mimic human disease processes. Here we describe a model of the artery consisting of monocultures of human coronary artery endothelial cells (HCAECs) or cocultures of HCAECs with human coronary artery smooth muscle cells (HCASMCs). The model was established in the OrganoPlate® 2-lane-48 UF, a novel microfluidic device, comprised of a microtiter plate footprint with 48 chips. Fluid is circulated in a unidirectional manner by interval rocking. The creation of an air-liquid interface at the inlets at a given inclination is used to select flow paths and establish flow in one direction only, whilst capillary forces ensure the channel remains filled with fluid. We investigated the impact of unidirectional or bidirectional flow conditions. Under unidirectional flow, endothelial cells aligned with the flow direction, decreased fibronectin deposition, and smooth muscle cells presented a non-contractile phenotype, emulating the characteristics of healthy arteries. Contrarily, bidirectional flow mimicked features of early endothelial dysfunction, such as contractile morphology of vessels and increased fibronectin secretion, ICAM-1 staining, and lipid deposits. Vascular inflammation could be induced by the addition of TNFα and IL-1β in both flow conditions. Overall, the OrganoPlate® 2-lane-48 UF is a powerful platform providing both throughput and improved flow control, for creating more physiological models. Its ability to replicate key features of a healthy and diseased artery, its potential use in drug screening, and its compatibility with lab automation make it an invaluable tool for researchers aiming for more accurate and efficient therapeutic development in CVD.

Targeting endothelial KCa channels in vivo restores arterial and endothelial function in type 2 diabetic rats

OBJECTIVE

This study tested the hypothesis that administration of the KCa channel activator SKA-31 restores endothelium-dependent vasodilation in vivo in Type 2 Diabetic (T2D) rats.

BACKGROUND

Acute treatment of isolated resistance arteries from T2D rats and humans with SKA-31 significantly improved endothelium-dependent vasodilation. However, it is unknown whether these in situ actions translate to intact vascular beds in vivo.

METHODS

Male Sprague Dawley (SD) and T2D Goto-Kakizaki (GK) rats (26-32 weeks of age) were injected intraperitoneally with either drug vehicle or 10 mg/kg SKA-31. Doppler ultrasound imaging was used to record reactive hyperemia/flow-mediated dilation (FMD) in the femoral artery following release of an occlusion cuff on the distal hind limb, along with diameter changes in the left main coronary artery in response to inhaled isoflurane (2 % → 5 %).

RESULTS

Vehicle treated SD rats exhibited a robust and reversible FMD response, the magnitude and time course of which did not differ in SD rats treated with SKA-31. In contrast, only a weak FMD response was observed in vehicle-treated T2D GK rats, whereas prior SKA-31 administration restored FMD to the level observed in control SD rats. Exposure of SD rats to 5 % isoflurane caused robust coronary artery dilation, which was not altered by prior treatment with SKA-31. In T2D GK rats, 5 % isoflurane inhalation alone did not increase coronary artery diameter, however, a strong vasodilatory response was observed following SKA-31 treatment. SKA-31 administration did not modify intrinsic heart rate responses in either protocol.

CONCLUSIONS

Enhancement of KCa channel activity in vivo restores endothelium-dependent vasodilation in T2D rats that exhibit peripheral endothelial dysfunction.

Applications of peptides in nanosystems for diagnosing and managing bacterial sepsis

Sepsis represents a critical medical condition stemming from an imbalanced host immune response to infections, which is linked to a significant burden of disease. Despite substantial efforts in laboratory and clinical research, sepsis remains a prominent contributor to mortality worldwide. Nanotechnology presents innovative opportunities for the advancement of sepsis diagnosis and treatment. Due to their unique properties, including diversity, ease of synthesis, biocompatibility, high specificity, and excellent pharmacological efficacy, peptides hold great potential as part of nanotechnology approaches against sepsis. Herein, we present a comprehensive and up-to-date review of the applications of peptides in nanosystems for combating sepsis, with the potential to expedite diagnosis and enhance management outcomes. Firstly, sepsis pathophysiology, antisepsis drug targets, current modalities in management and diagnosis with their limitations, and the potential of peptides to advance the diagnosis and management of sepsis have been adequately addressed. The applications have been organized into diagnostic or managing applications, with the last one being further sub-organized into nano-delivered bioactive peptides with antimicrobial or anti-inflammatory activity, peptides as targeting moieties on the surface of nanosystems against sepsis, and peptides as nanocarriers for antisepsis agents. The studies have been grouped thematically and discussed, emphasizing the constructed nanosystem, physicochemical properties, and peptide-imparted enhancement in diagnostic and therapeutic efficacy. The strengths, limitations, and research gaps in each section have been elaborated. Finally, current challenges and potential future paths to enhance the use of peptides in nanosystems for combating sepsis have been deliberately spotlighted. This review reaffirms peptides' potential as promising biomaterials within nanotechnology strategies aimed at improving sepsis diagnosis and management.

Effect of Carotid Body Denervation on Systemic Endothelial Function in a Diabetic Animal Model

Endothelial dysfunction is an essential intermediary for development of cardiovascular diseases associated with diabetes and hypertension (HT). The carotid body (CB) dysfunction contributes to dysmetabolic states, and the resection of carotid sinus nerve (CSN) prevents and reverts dysmetabolism and HT. Herein, we investigated if CSN denervation ameliorates systemic endothelial dysfunction in an animal model of type 2 diabetes mellitus (T2DM).We used Wistar male rats submitted to HFHSu diet during 25 weeks and the correspondent age-matched controls fed with a standard diet. CSN resection was performed in half of the groups after 14 weeks of diet. In vivo insulin sensitivity, glucose tolerance and blood pressure, ex vivo aortic artery contraction and relaxation and nitric oxide (NO) levels in plasma and aorta, aorta nitric oxide synthase (NOS) isoforms, and PGF2αR levels were evaluated.We demonstrated that, alongside to dysmetabolism and HT reversion, CSN resection restores endothelial function in the aorta and decreases the NO levels in plasma and aorta at the same time that restores normal levels of iNOS in aorta without changing eNOS or PGF2αR levels.These results suggest that the modulation of CB activity can be important for the treatment of HT and endothelial dysfunction related with T2DM.

Type 2 diabetes progression differently affects endothelial function and vascular contractility in the aorta and the pulmonary artery

Type 2 diabetes (T2D) is associated with cardiovascular and pulmonary disease. How T2D affects pulmonary endothelial function is not well characterized. We investigated the effects of T2D progression on contractility machinery and endothelial function in the pulmonary and systemic circulation and the mechanisms promoting the dysfunction, using pulmonary artery (PA) and aorta. A high-fat (HF, 3 weeks 60% lipid-rich diet) and a high-fat/high-sucrose (HFHSu, combined 60% lipid-rich diet and 35% sucrose during 25 weeks) groups were used as prediabetes and T2D rat models. We found that T2D progression differently affects endothelial function and vascular contractility in the aorta and PA, with the contractile machinery being altered in the PA and aorta in prediabetes and T2D animals; and endothelial function being affected in both models in the aorta but only affected in the PA of T2D animals, meaning that PA is more resistant than aorta to endothelial dysfunction. Additionally, PA and systemic endothelial dysfunction in diabetic rats were associated with alterations in the nitrergic system and inflammatory pathways. PA dysfunction in T2D involves endothelial wall mineralization. The understanding of the mechanisms behind PA dysfunction in T2D can lead to significant advances in both preventative and therapeutic treatments of pulmonary disease-associated diabetes.

Tea consumption and its effects on primary and secondary prevention of coronary artery disease: Qualitative synthesis of evidence from randomized controlled trials

BACKGROUND AND AIMS

There is a general interest in understanding how the consumption of tea impacts cardiovascular function in individuals at risk of developing cardiovascular disease (CVD). The current review focuses on evidence from randomized controlled trials (RCTs) reporting on associations between tea consumption and endothelial function, in the primary and secondary prevention of coronary artery disease (CAD).

METHODS

PubMed, EMBASE, and Google Scholar databases/search engines were used to identify eligible studies. Included studies had to report on the impact of tea supplementation of endothelial function or CAD related markers. In addition to flow-mediated dilation (FMD), makers of oxidative stress and inflammation such as oxidized low-density lipoprotein and C-reactive protein were considered as determinants of endothelial function. A total of 34 RCTs met the inclusion criteria, and these reported on the impact of tea consumption on endothelial function in individuals at risk of CVD or patients with CAD.

RESULTS

The current qualitative synthesis of literature demonstrates that beyond enhancing nitric oxide bioavailability and lowering blood pressure, regular consumption of tea and its active ingredients such as epigallocatechin gallate may be beneficial in reducing markers of oxidative stress and inflammation. Moreover, the reduction of oxidized low-density lipoprotein and C-reactive protein levels, could be a sign of improved endothelial function in individuals at increased risk of developing CVD.

CONCLUSIONS

The cumulative evidence also suggests that the development of epigallocatechin gallate as a nutraceutical or enriching foods with this bioactive compound could be a feasible strategy to improve endothelial function and lower CVD-risk. However, well-designed RCTs are still necessary to confirm long-term benefits of tea consumption on vascular health.

KCa channel activation normalizes endothelial function in Type 2 Diabetic resistance arteries by improving intracellular Ca2+ mobilization

BACKGROUND

Endothelial dysfunction is an early pathogenic event in the progression of cardiovascular disease in patients with Type 2 Diabetes (T2D). Endothelial KCa2.3 and KCa3.1 K⁺ channels are important regulators of arterial diameter, and we thus hypothesized that SKA-31, a small molecule activator of KCa2.3 and KCa3.1, would positively influence agonist-evoked dilation in myogenically active resistance arteries in T2D.

METHODOLOGY

Arterial pressure myography was utilized to investigate endothelium-dependent vasodilation in isolated cremaster skeletal muscle resistance arteries from 22 to 24 week old T2D Goto-Kakizaki rats, age-matched Wistar controls, and small human intra-thoracic resistance arteries from T2D subjects. Agonist stimulated changes in cytosolic free Ca²⁺ in acutely isolated, single endothelial cells from Wistar and T2D Goto-Kakizaki cremaster and cerebral arteries were examined using Fura-2 fluorescence imaging.

MAIN FINDINGS

Endothelium-dependent vasodilation in response to acetylcholine (ACh) or bradykinin (BK) was significantly impaired in isolated cremaster arteries from T2D Goto-Kakizaki rats compared with Wistar controls, and similar results were observed in human intra-thoracic arteries. In contrast, inhibition of myogenic tone by sodium nitroprusside, a direct smooth muscle relaxant, was unaltered in both rat and human T2D arteries. Treatment with a threshold concentration of SKA-31 (0.3 μM) significantly enhanced vasodilatory responses to ACh and BK in arteries from T2D Goto-Kakizaki rats and human subjects, whereas only modest effects were observed in non-diabetic arteries of both species. Mechanistically, SKA-31 enhancement of evoked dilation was independent of vascular NO synthase and COX activities. Remarkably, SKA-31 treatment improved agonist-stimulated Ca²⁺ elevation in acutely isolated endothelial cells from T2D Goto-Kakizaki cremaster and cerebral arteries, but not from Wistar control vessels. In contrast, SKA-31 treatment did not affect intracellular Ca²⁺ release by the sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA) inhibitor cyclopiazonic acid.

CONCLUSIONS

Collectively, our data demonstrate that KCa channel modulation can acutely restore endothelium-dependent vasodilatory responses in T2D resistance arteries from rats and humans, which appears to involve improved endothelial Ca²⁺ mobilization.

Role of oxylipins generated from dietary PUFAs in the modulation of endothelial cell function

Oxylipins, which are circulating bioactive lipids generated from polyunsaturated fatty acids (PUFAs) by cyclooxygenase, lipooxygenase and cytochrome P450 enzymes, have diverse effects on endothelial cells. Although studies of the effects of oxylipins on endothelial cell function are accumulating, a review that provides a comprehensive compilation of current knowledge and recent advances in the context of vascular homeostasis is lacking. This is the first compilation of the various in vitro, ex vivo and in vivo reports to examine the effects and potential mechanisms of action of oxylipins on endothelial cells. The aggregate data indicate docosahexaenoic acid-derived oxylipins consistently show beneficial effects related to key endothelial cell functions, whereas oxylipins derived from other PUFAs exhibit both positive and negative effects. Furthermore, information is lacking for certain oxylipin classes, such as those derived from α-linolenic acid, which suggests additional studies are required to achieve a full understanding of how oxylipins affect endothelial cells.

Calcium Channel Blockers in Restoration of Endothelial Function: Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Clinical evaluation of the Endothelial Function (EF) is becoming an essential step in the quality assessment of cardiovascular risk prevention and rational pharmacotherapy of cardiovascular disorders. The existing pieces of evidence suggested that Calcium Channel Blockers (CCB) can induce positive effects on impaired EF.

OBJECTIVE

To evaluate the effects of CCB on EF, we performed a meta-analysis of available data from randomized and placebo-controlled or other treatment-controlled clinical studies encompassing effects of CCB on EF, as measured by Flow-Mediated Dilation (FMD) of the brachial artery.

METHODS

The relevant clinical studies were searched by systematic exploration of the appropriate databases until November 30, 2017. A random-effect model was conducted. The primary outcome was the percentage change in FMD between the baseline and the final levels in response to investigated drugs.

RESULTS

Fifteen randomized clinical studies with 33 arms were identified. CCB improved FMD more pronounced than thiazide diuretics - TD (3 studies, 157 participants, WMD=2.08%, 95% CI=0.35-3.80%; P=0.02). Oppositely, ACE Inhibitors (ACEI) and Angiotensin Receptor Blockers (ARB) notably improved FMD if compared to CCB (CCB vs. ACEI: 5 studies, 533 participants, WMD = -1.62%, 95% CI = -2.74% to -0.50%; P=0.005; and CCB vs. ARB: 9 studies, 669 participants, WMD = -1.52%, 95% CI = -2.22% to -0.81%; P=0.0001). CCB effects on EF were similar to those evoked by beta blockers or placebo.

CONCLUSION

CCB improved EF to a more prominent extent only if paralleled to TD, while inversely; ACEI and ARB were more effective in augmenting FMD.

Stromal Cell-Derived Factor 1 Protects Brain Vascular Endothelial Cells from Radiation-Induced Brain Damage

Stromal cell-derived factor 1 (SDF-1) and its main receptor, CXC chemokine receptor 4 (CXCR4), play a critical role in endothelial cell function regulation during cardiogenesis, angiogenesis, and reendothelialization after injury. The expression of CXCR4 and SDF-1 in brain endothelial cells decreases due to ionizing radiation treatment and aging. SDF-1 protein treatment in the senescent and radiation-damaged cells reduced several senescence phenotypes, such as decreased cell proliferation, upregulated p53 and p21 expression, and increased senescence-associated beta-galactosidase (SA-β-gal) activity, through CXCR4-dependent signaling. By inhibiting extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription protein 3 (STAT3), we confirmed that activation of both is important in recovery by SDF-1-related mechanisms. A CXCR4 agonist, ATI2341, protected brain endothelial cells from radiation-induced damage. In irradiation-damaged tissue, ATI2341 treatment inhibited cell death in the villi of the small intestine and decreased SA-β-gal activity in arterial tissue. An ischemic injury experiment revealed no decrease in blood flow by irradiation in ATI2341-administrated mice. ATI2341 treatment specifically affected CXCR4 action in mouse brain vessels and partially restored normal cognitive ability in irradiated mice. These results demonstrate that SDF-1 and ATI2341 may offer potential therapeutic approaches to recover tissues damaged during chemotherapy or radiotherapy, particularly by protecting vascular endothelial cells.

Search for new pharmacological targets for increasing the efficiency of correction of cardiovascular diseases

Introduction: Cardiovascular disease (CVD) is the leading cause of death worldwide: no other reason causes as many deaths a year as CVD. An estimated 17.9 million people died of CVD in 2016, accounting for 31% of all deaths in the world. People with CVD or at high risk for these diseases (due to one or more risk factors, such as high blood pressure, diabetes, hyperlipidemia, or an already developed disease) need early detection and assistance through counseling and, if necessary, taking medication.

Ways to find new targets for the correction of endothelium-associated pathology: The basis of the modern therapy for arterial hypertension and other cardiovascular diseases is the postulate of the need to correct endothelial dysfunction as an indication of the adequacy of antihypertensive and other types of treatment. Lowering blood pressure (BP) without normalizing endothelial function cannot be considered a successfully resolved clinical task. Currently, there are no drugs for specific pharmacological correction of endothelial dysfunction in cardiovascular diseases, and the search for new targets for pharmacological correction of endothelial dysfunction is one of the main tasks of pharmacology.

Modulation of endothelial cell responses and vascular function by dietary fatty acids

Healthy and functional endothelial cells play important roles in maintaining vascular homeostasis, whereas endothelial dysfunction initiates and exacerbates vascular disease progression. Interventional studies with dietary fatty acids have shown that these molecules have varying effects on vascular function. It is hypothesized that the actions of dietary fatty acids on vascular function may be mediated in part through endothelial cells. This review summarizes the results of studies that have examined the acute and chronic effects of dietary fatty acids on endothelial function and vascular properties in humans, as well as the potential mechanisms by which n-3 polyunsaturated fatty acids regulate endothelial function. Altogether, this article provides an extensive review of how fatty acids contribute to vascular function through their ability to modulate endothelial cells and discusses relationships between dietary fatty acids and endothelial cells in the context of vascular dysfunction.

Increased ischemic stroke risk in patients with Behçet's disease: A nationwide population-based cohort study

Background

Behçet’s disease (BD) is a recurrent, multisystemic, inflammatory disorder that mainly affects blood vessels. Because recurrent inflammation of blood vessels in the brain plays a crucial role in the development of ischemic stroke, we hypothesized that patients with BD might have an elevated risk of ischemic stroke. This potential association has been suggested in a few case reports, but not epidemiological studies. Hence, the present study aimed to examine the relation between BD and subsequent ischemic stroke in Taiwan using a nationwide, population-based database.

Methods

To establish a study cohort, the longitudinal data of 306 patients newly diagnosed with BD during 2000–2010 were extracted from the National Health Insurance Research Database, Taiwan. For comparison of ischemic stroke incidence, a control cohort of 1224 subjects without BD was established using a frequency-matched ratio of 1:4 for age, sex, and pre-existing comorbidities.

Results

During the 10-year follow-up, 13 (4.2%) patients with BD and 20 (1.6%) control subjects experienced ischemic stroke. Kaplan–Meier analysis revealed the higher prevalence of ischemic stroke in the BD group (log-rank test, p = 0.001). After adjusting for comorbidities and demographic characteristics, Cox regression analysis revealed that patients with BD had a 2.77-fold risk of ischemic stroke (95% confidence interval, 1.38–5.57) compared to control subjects.

Conclusions

Patients with BD have an elevated risk of ischemic stroke. Hence, BD may affect the vascular system in the brain, resulting in a stroke event.

Health benefits of resveratrol: Evidence from clinical studies

Resveratrol is a polyphenolic nutraceutical that exhibits pleiotropic activities in human subjects. The efficacy, safety, and pharmacokinetics of resveratrol have been documented in over 244 clinical trials, with an additional 27 clinical trials currently ongoing. Resveretrol is reported to potentially improve the therapeutic outcome in patients suffering from diabetes mellitus, obesity, colorectal cancer, breast cancer, multiple myeloma, metabolic syndrome, hypertension, Alzheimer's disease, stroke, cardiovascular diseases, kidney diseases, inflammatory diseases, and rhinopharyngitis. The polyphenol is reported to be safe at doses up to 5 g/d, when used either alone or as a combination therapy. The molecular basis for the pleiotropic activities of resveratrol are based on its ability to modulate multiple cell signaling molecules such as cytokines, caspases, matrix metalloproteinases, Wnt, nuclear factor-κB, Notch, 5'-AMP-activated protein kinase, intercellular adhesion molecule, vascular cell adhesion molecule, sirtuin type 1, peroxisome proliferator-activated receptor-γ coactivator 1α, insulin-like growth factor 1, insulin-like growth factor-binding protein 3, Ras association domain family 1α, pAkt, vascular endothelial growth factor, cyclooxygenase 2, nuclear factor erythroid 2 like 2, and Kelch-like ECH-associated protein 1. Although the clinical utility of resveratrol is well documented, the rapid metabolism and poor bioavailability have limited its therapeutic use. In this regard, the recently produced micronized resveratrol formulation called SRT501, shows promise. This review discusses the currently available clinical data on resveratrol in the prevention, management, and treatment of various diseases and disorders. Based on the current evidence, the potential utility of this molecule in the clinic is discussed.

The enhancement of serotonin-induced contraction of rat femoral artery is mediated by angiotensin II release from intact endothelium

We have performed an in vitro study on isolated intact or denuded femoral artery (FA) of healthy, diabetic, and/or rats submitted to the FA occlusion. The aim was to determine the contribution of endothelium and endothelial dysfunction (ED) on serotonin-induced action in FA. Further, the contribution of angiotensin II and cyclooxygenase products of arachidonic acid was investigated. A marker of ED, vWF was measured in animal serum. Serotonin induced contraction-dependent contraction of isolated FA, which was increased in preparations with endothelium. Pathological conditions such as endothelial denudation, nicotine-induced ED, diabetes or occlusion of FA reduced serotonin-induced contraction. Comparable reduction of serotonin-induced contraction was achieved after inhibition of AT1 receptors with losartan in isolated FA with intact endothelium. Our results demonstrate that angiotensin II contributes to the enhancement of serotonin-induced contraction of femoral arteries with intact endothelium. This increase is attenuated by endothelium removal, nicotine treatment, vascular occlusion, and/or hyperglycemia.

Endothelotropic Activity of 4-Hydroxy-3,5-Di-Tret-Butylcinnamic Acid in the Conditions of Experimental Cerebral Ischemia

Introduction: The aim of the study was to evaluate the endothelioprotective activity of 4-hydroxy-3,5-di-tret-butylcinnamic acid in conditions of experimental cerebral ischemia.

Materials and Methods: The brain ischemia was reproduced by the method of irreversible right-sided thermocoagulation of the middle cerebral artery. As comparative drugs, mexidol (30 mg/kg) and sulodexide (30 U/kg) were used. The vasodilating function of the vascular endothelium was assessed by the change in the rate of cerebral blood flow when the synthesis of nitric oxide was modified. Antithrombotic function was assessed by changes in the concentration of thromboxane A2, fibrinogen, von Willebrand factor activity and platelet aggregation activity. Serum concentration of C-reactive protein served as a marker of the state of anti-inflammatory endothelial function. To determine the potential mechanism of endothelioprotective activity of 4-4-hydroxy-3,5-di-tret-butylcinnamic acid, the anti-radical activity of this compound toward superoxide and nitrosy-radicals was assessed; and the effect of the compound on the mitochondrial function was studied, by evaluating the functional activity of mitochondrial ATP synthetase and cytochrome-c-oxidase by ELISA.

Results and Discussion: In the course of the study, a positive effect of 4-hydroxy-3,5-di-tret-butylcinnamic acid on the state of endothelial function in cerebral ischemia was established, which was expressed in the preservation of vasodilating (restoring the vascular reaction to acetylcholine, nitro-L-arginine methyl ether, L-arginine), antithrombotic (a decrease in the concentration of thromboxane A2, fibrinogen and von Willebrand factor activity by 241.9% (p <0.05), 73.5% (p <0.05), 20.4% (p <0.05), respectively, a decrease in the degree of aggregation and platelet aggregation rate by 56.7 % (p <0.05) and 52.8% (p <0.05), respectively, and anti-inflammatory vascular endothelial function (99.1% C-reactive protein reduction (p <0.05)). The 4-hydroxy-3,5-di-tret-butylcinnamic acid compound in vitro tests suppressed generation of superoxide (IC50 = 1.99 mg/ml) and nitrosyl radical (IC50 = 1.92 mg/ml), eliminated NO-synthase uncoupling, and restored the mitochondrial function (increase in mitochondrial ATP synthase and cytochrome-c-oxidase activity by 23.5% (p <0.05) and 110.8% (p <0.05), respectively).

Conclusion: The study demonstrated the presence of endotheliotropic activity of 4-hydroxy-3,5-di-tret-butylcinnamic acid, which is expressed in the preservation of vasodilating, antithrombotic and anti-inflammatory functions of the vascular endothelium in conditions of cerebral ischemia. At the same time, the anti-radical properties of this compound, as well as the direct effect on the functional activity of the NO-synthase system and the improvement of the mitochondrial function, may underlie the endotheliotropic effects of 4-hydroxy-3,5-di-tret-butylcinnamic acid.

Follistatin-Like 3 Enhances the Function of Endothelial Cells Derived from Pluripotent Stem Cells by Facilitating β-Catenin Nuclear Translocation Through Inhibition of Glycogen Synthase Kinase-3β Activity

The fight against vascular disease requires functional endothelial cells (ECs) which could be provided by differentiation of induced Pluripotent Stem Cells (iPS Cells) in great numbers for use in the clinic. However, the great promise of the generated ECs (iPS-ECs) in therapy is often restricted due to the challenge in iPS-ECs preserving their phenotype and function. We identified that Follistatin-Like 3 (FSTL3) is highly expressed in iPS-ECs, and, as such, we sought to clarify its possible role in retaining and improving iPS-ECs function and phenotype, which are crucial in increasing the cells' potential as a therapeutic tool. We overexpressed FSTL3 in iPS-ECs and found that FSTL3 could induce and enhance endothelial features by facilitating β-catenin nuclear translocation through inhibition of glycogen synthase kinase-3β activity and induction of Endothelin-1. The angiogenic potential of FSTL3 was also confirmed both in vitro and in vivo. When iPS-ECs overexpressing FSTL3 were subcutaneously injected in in vivo angiogenic model or intramuscularly injected in a hind limb ischemia NOD.CB17-Prkdcscid/NcrCrl SCID mice model, FSTL3 significantly induced angiogenesis and blood flow recovery, respectively. This study, for the first time, demonstrates that FSTL3 can greatly enhance the function and maturity of iPS-ECs. It advances our understanding of iPS-ECs and identifies a novel pathway that can be applied in cell therapy. These findings could therefore help improve efficiency and generation of therapeutically relevant numbers of ECs for use in patient-specific cell-based therapies. In addition, it can be particularly useful toward the treatment of vascular diseases instigated by EC dysfunction. Stem Cells 2018;36:1033-1044.

Total Hip Replacement Provokes Endothelial Dysfunction

Surgery represents an increased risk of different perioperative complications. Endothelial function (EF) is a key mechanism responsible for cardiovascular homeostasis and is involved in thromboembolic complications. We aimed to follow changes of EF in an early postoperative period in patients undergoing total hip replacement (THR). Endothelial function was assessed noninvasively in 70 consecutive patients who underwent an elective THR under spinal anesthesia. Flow-mediated dilation (FMD) and low flow-mediated constriction capability of the brachial artery, which are indicators of EF were measured before the operation (baseline), 24 hours after the operative procedure, and 5 to 7 days postoperatively. Baseline FMD was 12.3% and decreased a day after surgery to 7.3% ( P < .001). After 5 to 7 days, it gradually increased to 9.2%. However, on average, it was lower than before surgery ( P < .001). The median duration of THR was 85.0 (65.0-100.0) minutes, the average hospital length of stay was 7 days. Total hip replacement is associated with an immediate decrease in FMD which remains significantly decreased 5 to 7 days after the surgery compared with the preoperative value. These results indicate that surgery provokes endothelial dysfunction and deteriorates cardiovascular homeostasis. This effect could be involved in cardiovascular complications in the postoperative period.

3',4'-dihydroxyflavonol ameliorates endoplasmic reticulum stress-induced apoptosis and endothelial dysfunction in mice

Endoplasmic reticulum (ER) stress has been implicated in the development of hypertension 3 through the induction of endothelial impairment. As 3′,4′-dihydroxyflavonol (DiOHF) 4 reduces vascular injury caused by ischaemia/reperfusion or diabetes, and flavonols have been demonstrated to attenuate ER stress, we investigated whether DiOHF can protect mice from ER stress-induced endothelial dysfunction. Male C57BLK/6 J mice were injected with tunicamycin to induce ER stress in the presence or absence of either DiOHF or tauroursodeoxycholic acid (TUDCA), an inhibitor of ER stress. Tunicamycin elevated blood pressure and impaired endothelium-dependent relaxation. Moreover, in aortae there was evidence of ER stress, oxidative stress and reduced NO production. This was coincident with increased NOX2 expression and reduced phosphorylation of endothelial nitric oxide synthase (eNOS) on Ser1176. Importantly, the effects of tunicamycin were significantly ameliorated by DiOHF or TUDCA. DiOHF also inhibited tunicamycin-induced ER stress and apoptosis in cultured human endothelial cells (HUVEC). These results provide evidence that ER stress is likely an important initiator of endothelial dysfunction through the induction of oxidative stress and a reduction in NO synthesis and that DiOHF directly protects against ER stress- induced injury. DiOHF may be useful to prevent ER and oxidative stress to preserve endothelial function, for example in hypertension.

Role of free fatty acids in endothelial dysfunction

Plasma free fatty acids levels are increased in subjects with obesity and type 2 diabetes, playing detrimental roles in the pathogenesis of atherosclerosis and cardiovascular diseases. Increasing evidence showing that dysfunction of the vascular endothelium, the inner lining of the blood vessels, is the key player in the pathogenesis of atherosclerosis. In this review, we aimed to summarize the roles and the underlying mechanisms using the evidence collected from clinical and experimental studies about free fatty acid-mediated endothelial dysfunction. Because of the multifaceted roles of plasma free fatty acids in mediating endothelial dysfunction, elevated free fatty acid level is now considered as an important link in the onset of endothelial dysfunction due to metabolic syndromes such as diabetes and obesity. Free fatty acid-mediated endothelial dysfunction involves several mechanisms including impaired insulin signaling and nitric oxide production, oxidative stress, inflammation and the activation of the renin-angiotensin system and apoptosis in the endothelial cells. Therefore, targeting the signaling pathways involved in free fatty acid-induced endothelial dysfunction could serve as a preventive approach to protect against the occurrence of endothelial dysfunction and the subsequent complications such as atherosclerosis.

Angiotensin receptor blockers & endothelial dysfunction: Possible correlation & therapeutic implications

The endothelium is one of the most important constituents of vascular homeostasis, which is achieved through continual and balanced production of different relaxing and contractile factors. When there is a pathological disturbance in release of these products, endothelial dysfunction (ED) will probably occur. ED is considered to be the initial step in the development of atherosclerosis. This pathological activation and inadequate functioning of endothelial cells was shown to be to some extent a reversible process, which all together resulted in increased interest in investigation of different beneficial treatment options. To this point, the pharmacological approach, including for example, the use of angiotensin-converting enzyme inhibitors or statins, was clearly shown to be effective in the improvement of ED. One of many critical issues underlying ED represents instability in the balance between nitric oxide and angiotensin II (Ang II) production. Considering that Ang II was confirmed to be important for the development of ED, the aim of this review article was to summarize the findings of up to date clinical studies associated with therapeutic application of angiotensin receptor blockers and improvement in ED. In addition, it was of interest to review the pleiotropic actions of angiotensin receptor blockers linked to the improvement of ED. The prospective, randomized, double-blind, placebo or active-controlled clinical trials were identified and selected for the final evaluation.

Sex-difference in expression and function of beta-adrenoceptors in macrovessels: role of the endothelium

Estrogen modulates adrenergic reactivity of macrovessels, resulting in weaker α-adrenergic vasoconstriction in females than males. However, the mechanisms governing this important sex-specific difference are not well understood. We hypothesized that vessels of females express more dilatory β-adrenoceptors, which counteract constrictive effects of α-adrenoceptors. This hypothesis was tested using aortas of normotensive (WKY) and hypertensive rats (SHR), along with human mammary artery. Selective blockade of β₁ (CGP20712) or β₃ (SR59230A), but not β₂ (ICI118,551) adrenoceptors, greatly increased α-adrenergic constriction (norepinephrine) of aorta in female SHRs, but not in male SHRs at 12 weeks of age. Consistently, the selective β₁/β₂ (isoproterenol) and β₃-adrenergic (BRL37344) relaxation was stronger in female SHRs than in males. Removal of endothelium and use of L-NMMA abolished sex-difference in α-adrenergic constriction and β-adrenergic relaxation. Immunostainings revealed endothelial localization of β₁- and β₃-adrenoceptors. mRNA levels of aortic β₁- and β₃-, but not β₂-adrenoceptors were markedly higher in female than in male SHRs. The sex-specific differences in α-adrenergic constriction and β-adrenoceptor mRNA levels were age-dependent, predominantly present up to 29 weeks and disappeared at 36 weeks of age. The sex-specific difference was not strain-dependent and was similarly present in normotensive WKY rats. Human mammary artery of women showed a weaker α-adrenergic constriction than arteries of men. This sex-specific difference was prominent at 45-65 years and disappeared with aging. Our results convincingly demonstrate that female macrovessels express more dilatory β₁- and β₃-adrenoreceptors than male vessels with a predominant endothelial localization. This sex-specific difference is functionally relevant in young adults and is attenuated with aging.

QGQS Granule in SHR Serum Metabonomics Study Based on Tools of UPLC-Q-TOF and Renin-Angiotensin-Aldosterone System Form Protein Profilin-1

QGQS granule is effective for the therapeutic of hypertension in clinic. The aim of this research is to observe the antihypertension effect of QGQS granule on SHR and explain the mechanism of its lowering blood pressure. 30 SHR were selected as model group, captopril group, and QGQS group, 10 WKYr were used as control group, and RBP were measured on tail artery consciously. And all the serum sample analysis was carried out on UPLC-TOF-MS system to determine endogenous metabolites and to find the metabonomics pathways. Meanwhile, ELISA kits for the determination pharmacological indexes of PRA, AngI, AngII, and ALD were used for pathway confirmatory; WB for determination of profilin-1 protein expression was conducted for Ang II pathway analysis as well. It is demonstrated that QGQS granule has an excellent therapeutic effect on antihypertension, which exerts effect mainly on metabonomics pathway by regulating glycerophospholipid, sphingolipid, and arachidonic acid metabolism, and it could inhibit the overexpression of the profilin-1 protein. We can come to a conclusion that RAAS should be responsible mainly for the metabonomics pathway of QGQS granule on antihypertension, and it plays a very important role in protein of profilin-1 inhibition.

Number and function of circulating endothelial progenitor cells in patients with primary Budd-Chiari syndrome

BACKGROUND AND AIM

Primary Budd-Chiari syndrome (BCS) is associated with vascular endothelial injury. Circulating endothelial progenitor cells (EPCs) provide an endogenous mechanism to repair endothelial injury. This study investigated the levels and functionality of EPCs in patients with primary BCS.

METHODS

EPCs (CD34⁺/CD133⁺/KDR⁺) were quantified in 82 patients with primary BCS (inferior vena cava type: n=19; hepatic vein type: n=22; and mixed type: n=41), 10 cirrhosis controls (CC group) and 10 age-matched healthy controls (HC group), using flow cytometry. EPCs proliferation was detected by MTT assay, adhesion by adhesion activity assay, and migration capacity by Transwell assay.

RESULTS

EPCs levels were significantly lower in the BCS group (0.020±0.005%) than in the CC and HC groups (0.260±0.201%, 0.038±0.007%; P<0.001 for each). EPCs cultured in vitro from BCS and CC groups had, respectively, lower proliferation activity (0.20±0.04, 0.23±0.06 vs 0.58±0.07, each P<0.001), adhesion activity (15.8±1.7, 18.2±4.3 vs 35.0±2.5 cells/random microscopic field (RMF), each P<0.001) and migration activity (16.1±1.5, 16.7±3.0 vs 23.9±2.0 cells/RMF, each P<0.001) than in the HC group. EPCs functionality did not significantly differ between the BCS and CC groups. The numbers and functions of EPCs did not significantly differ among patients with inferior vena cava type, hepatic vein type and mixed type of BCS.

CONCLUSION

Patients with primary BCS had lower EPCs levels, with less proliferation, adhesion and migration activities. These findings suggest that lower levels of less functional EPCs may be associated with venous occlusion in primary BCS patients.

Impaired endothelial function and arterial stiffness in patients with type 2 diabetes - The effect of a very low-dose combination of fluvastatin and valsartan

AIM

Patients with type 2 diabetes are at increased cardiovascular risk. The aim was to explore whether the impaired arterial wall characteristics typical of these patients could be improved by the unique beneficial effects of a very low-dose combination of fluvastatin and valsartan (low-flu/val).

METHODS

Forty middle-aged males (50.4±6.1years) with type 2 diabetes were recruited to a double-blind, randomized study. Patients (N=20) received low-flu/val (10/20mg) or placebo (N=20) over 30days in addition to their regular therapy. Brachial artery flow mediated dilation (FMD), common carotid artery pulse wave velocity (PWV) and β-stiffness were assessed before and after treatment, and 3 and 6months after treatment discontinuation. The treatment was then repeated.

RESULTS

Arterial wall characteristics significantly improved. After 30days of intervention, FMD increased from 2.4±0.3 to 4.2±0.3 (p<0.001), PWV decreased from 6.4±0.1 to 5.8±0.2 (p<0.001) and β stiffness decreased from 7.8±0.4 to 6.7±0.4 (p<0.001). Lipids and arterial pressure did not change. After treatment discontinuation, the beneficial effects decreased over the following months. The repetition of treatment completely regained the initial benefits. No changes were observed in the placebo group.

CONCLUSIONS

Low-flu/val added on-top of optimal therapy substantially improves arterial wall characteristics in patients with type 2 diabetes.

The Endothelium as a Target for the Treatment of Heart Failure

The functional integrity of endothelial cells is a marker and a prerequisite for vascular health. It is well established that the endothelium not only modulates, but also mediates vascular disease processes. Certain diseases such as diabetes, dyslipidaemia, obesity, and arterial hypertension advance endothelial injury. The disease process induces cellular and functional changes in endothelial cells leading to a pathophysiological phenomenon referred to as endothelial cell dysfunction, which involves abnormal vasomotion, an imbalance in reactive oxygen species and nitric oxide, the activation of inflammation, and disruption of the coagulation process of the endothelial cells. With this knowledge, it is now known that vascular function plays a central role in the development and progression of heart failure (HF). HF is the primary cause of patient hospitalization. There is a strong desire to intervene and prevent the growing HF epidemic. Over the last decade, numerous therapies have been evaluated but few have led to positive results in the later stages of clinical trials. Efforts are currently being made to understand the pathophysiology of endothelial dysfunction and use this knowledge to identify novel agents or therapeutic targets that will improve the outcome of patients with HF and restore the normal function of the endothelium. The purpose of this review is to present a brief summary of the traditional approaches that have been taken to improve endothelial dysfunction and combat HF and, more importantly, to discuss some novel therapeutic approaches that are still under investigation, including the use of gene therapy and nanocarriers as means of delivering targets to the dysfunctional endothelium as treatment for HF.

Vitamin D and cardiovascular disease: From atherosclerosis to myocardial infarction and stroke

There continues to be interest in understanding the role of vitamin D in the pathogenesis, epidemiology and prevention of cardiovascular disease (CVD). In fact vitamin D deficiency has been associated to an increased risk of developing CVD given to the relationship between low vitamin D levels and obesity, diabetes mellitus, dyslipidaemia, endothelial dysfunction and hypertension. However, although vitamin D has been identified as a potentially important marker of CVD, the mechanisms through which vitamin D deficiency leads from endothelial dysfunction to myocardial infarction and stroke are not fully understood. Thus, the goal of this review is to provide an updated review of the literature on the basic science of how vitamin D may affect the cardiovascular system and in particular to analyze the role that vitamin D may have in the whole dynamic process from the initiation of endothelial dysfunction to the development of myocardial infarction and stroke.

A meta-analysis of randomized and placebo-controlled clinical trials suggests that coenzyme Q10 at low dose improves glucose and HbA1c levels

The influence of coenzyme Q10 (CoQ10) on blood glucose (BGL) and HbA1c (HL) levels has been previously investigated; however, the results are inconsistent. Therefore, the purpose of this meta-analysis was to determine if CoQ10 could affect BGL and HL levels based on the existing evidence. PubMed, Cochrane Library, Web of Science, Embase, and Scopus databases were searched for randomized clinical trials from September 1, 1956, to March 01, 2016. To calculate pooled overall effects, a random effect model was used. Because of the presence of heterogeneity, the subgroup analysis and the meta-regression were performed. In total, 18 studies (19 study arms) were included in our investigation focusing on the effects of CoQ10 on BGL (17 arms) and HL (12 arms) changes. CoQ10 significantly reduced BGL, whereas it was ineffective in the reduction of the HL. Because of the significant heterogeneity, in the arms involving BGL, we found that lower doses of CoQ10 (<200 mg/d) and a shorter duration of study created a positive effect on BGL. Also, it appeared that CoQ10 could reduce BGL in patients with a glucose level >6 mmol/L as well as in certain ethnic groups. However, because the meta-regression failed to support the subgroup analysis, the result related to the ethnic group should be used only to generate a hypothesis, which is planned in the future. In conclusion, CoQ10 can reduce BGL, particularly when used in lower doses (< 200 mg/d) and when administration was not longer than 12 weeks, in patients both with and without high BGL.

Vitamin D versus placebo in improvement of endothelial dysfunction: a meta-analysis of randomized clinical trials

AIMS

The possible effect of vitamin D administration in humans on endothelial dysfunction (ED) still remains undetermined. The current meta-analysis was performed to evaluate if vitamin D could improve ED.

METHODS

Randomized, double-blind, and placebo-controlled clinical trials were identified by systematic search of the PubMed, the Cochrane Library, the Web of Science and the Scopus data bases, as well as different reviews and clinical trials articles. A random effects model was used to calculate the pooled overall effect on flow-mediated dilation (FMD) linked to the vitamin D administration. Meta-regression and subgroup analyses were performed to evaluate the impact of study characteristics on the effect of vitamin D administration on FMD.

RESULTS

A total of eight studies with nine relevant study arms were identified. The obtained results of pooled analysis showed that vitamin D administration did not improve FMD (eight studies, 529 subjects; weighted mean difference (WMD): 0.96%, 95% CI: -1.24% to 2.06%; P = 0.09). This was probably due to significant heterogeneity in between included trials (I(2) = 84%, P < 0.00001). On the other hand, subgroup analysis demonstrated that vitamin D improved FMD in trials that lasted <16 weeks; if systolic blood pressure (SBP) was higher than 140 mmHg and in trials where diastolic blood pressure (DBP) was <80 mmHg.

CONCLUSION

Although the current evidence clearly demonstrates that in certain conditions vitamin D can improve ED, a larger number of clinical trials are needed to confirm this assumption to confirm or reject the final statement on this topic.

Thiazolidinediones improve flow-mediated dilation: a meta-analysis of randomized clinical trials

AIMS

Thiazolidinediones administration is assumed to be related with an improvement of endothelial dysfunction (ED); nevertheless, previous studies have been inconsistent. For this reason, the present meta-analysis was directed to estimate if thiazolidinediones were related to endothelial dysfunction improvement by using flow-mediated dilation (FMD) measurement.

METHODS

Literature search of the PubMed, the Cochrane Library, the Web of Science, and the Scopus databases was performed covering the period until July 01, 2015, for randomized clinical trials that investigated an influence of thiazolidinediones on FMD. For the calculation of the pooled overall effect, a random effect model was used. Meta-regression and subgroup analyses were performed to evaluate the impact of study characteristics on the effect of thiazolidinediones administration on FMD.

RESULTS

This meta-analysis included 16 studies with 812 subjects. The obtained results demonstrated an improvement of endothelial dysfunction measured with FMD (16 studies, 812 subjects; WMD: 2.4 %, 95 % CI = 1.1 to 3.69 %; p = 0.0003). The significant heterogeneity was noted (I (2) = 95 %, p < 0.00001). Subgroup analysis demonstrated that pioglitazone and rosiglitazone were able to improve FMD. Also, thiazolidinediones improved FMD if treatment was longer than 12 weeks and if patients were younger than 65 years. Additionally, a lipid profile was found to influence thiazolidinediones effect on FMD.

CONCLUSION

The results of this meta-analysis demonstrated that thiazolidinediones were able to improve FMD, which in clinical terms can be further translated to the improvement of an impaired endothelial function. Nevertheless, the link between FMD and its predictive clinical relevance still requires further clarification.

Boldine Ameliorates Vascular Oxidative Stress and Endothelial Dysfunction: Therapeutic Implication for Hypertension and Diabetes

Epidemiological and clinical studies have demonstrated that a growing list of natural products, as components of the daily diet or phytomedical preparations, are a rich source of antioxidants. Boldine [(S)-2,9-dihydroxy-1,10-dimethoxy-aporphine], an aporphine alkaloid, is a potent antioxidant found in the leaves and bark of the Chilean boldo tree. Boldine has been extensively reported as a potent "natural" antioxidant and possesses several health-promoting properties like anti-inflammatory, antitumor promoting, antidiabetic, and cytoprotective. Boldine exhibited significant endothelial protective effect in animal models of hypertension and diabetes mellitus. In isolated thoracic aorta of spontaneously hypertensive rats, streptozotocin-induced diabetic rats, and db/db mice, repeated treatment of boldine significantly improved the attenuated acetylcholine-induced endothelium-dependent relaxations. The endothelial protective role of boldine correlated with increased nitric oxide levels and reduction of vascular reactive oxygen species via inhibition of the nicotinamide adenine dinucleotide phosphate oxidase subunits, p47 and nicotinamide adenine dinucleotide phosphate oxidase 2, and angiotensin II-induced bone morphogenetic protein-4 oxidative stress cascade with downregulation of angiotensin II type 1 receptor and bone morphogenetic protein-4 expression. Taken together, it seems that boldine may exert protective effects on the endothelium via several mechanisms, including protecting nitric oxide from degradation by reactive oxygen species as in oxidative stress-related diseases. The present review supports a complimentary therapeutic role of the phytochemical, boldine, against endothelial dysfunctions associated with hypertension and diabetes mellitus by interfering with the oxidative stress-mediated signaling pathway.

Effect of aliskiren, telmisartan and torsemide on cardiac dysfunction in l-nitro arginine methyl ester (l-NAME) induced hypertension in rats

Comparative study of cardio protective effect of aliskiren, telmisartan, and torsemide was carried out on l-nitro arginine methyl ester (l-NAME) induced hypertension in rats. The three drugs were given daily for 8 weeks simultaneously with l-NAME, with a control group for each drug and l-NAME. The degree of protection was assessed by measurement of systolic blood pressure and heart rate of animals every two weeks. At the end of the experimental period blood sampling was carried out for estimation of the level of NO2 (-)/NO3 (-). After which animals were sacrificed for heart dissection to detect collagen types I and III gene expression. Histopathological study was done to evaluate the extension of collagen deposits. The study revealed that the three drugs decreased blood pressure significantly compared to l-NAME. There was no significant difference between aliskiren and telmisartan in all measurements, but there was significant decrease in measurements of both aliskiren and telmisartan treated groups compared to torsemide starting from 4th week. There were insignificant changes in pulse rate values between the three l-NAME treated groups through the experiment. The three drugs significantly increased NO compared to l-NAME. Collagen I and III gene expression was significantly decreased by the three drugs but the highest percentage of inhibition was with telmisartan compared to l-NAME. Comparing the percentage inhibition of cardiac fibrosis, there was insignificant difference between telmisartan and torsemide treated groups while both were superior to aliskiren. In conclusion, further experimental studies are required to elucidate the potential cardioprotective mechanisms of aliskiren, telmisartan and torsemide, and assess their efficacy in treatment of heart failure.

Endothelial progenitor cell biology in ankylosing spondylitis

AIM

Endothelial progenitor cells (EPCs) are unique populations which have reparative potential in overcoming endothelial damage and reducing cardiovascular risk. Patients with ankylosing spondylitis (AS) have increased risk of cardiovascular morbidity and mortality. The aim of this study was to investigate the endothelial progenitor cell population in AS patients and its potential relationships with disease variables.

METHODS

Endothelial progenitor cells were measured in peripheral blood samples from 20 AS and 20 healthy controls by flow cytometry on the basis of CD34 and CD133 expression. Disease activity was evaluated by using Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Functional ability was monitored by using Bath Ankylosing Spondylitis Functional Index (BASFI).

RESULTS

EPCs were depleted in AS patients as compared to healthy controls (CD34(+) /CD133(+) : 0.027 ± 0.010% vs. 0.044 ± 0.011%, P < 0.001). EPC depletions were significantly associated with disease duration (r = -0.52, P = 0.01), BASDAI (r = -0.45, P = 0.04) and C-reactive protein (r = -0.5, P = 0.01).

CONCLUSION

This is the first study to demonstrate endothelial progenitor cell depletion in AS patients. EPC depletions inversely correlate with disease duration, disease activity and inflammation, suggesting the pivotal role of inflammation in depletion of EPCs. EPC would possibly also serve as a therapeutic target for preventing cardiovascular disease in AS.

The effects of hyperuricaemia on flow-mediated and nitroglycerin-mediated dilatation in high-risk patients

BACKGROUND AND AIMS

Uric acid is emerging as one of the newer risk markers to consider in the cardiovascular risk assessment because it is demonstrated to be associated with adverse cardiovascular outcomes, particularly in high cardiovascular risk patients. One of the proposed mechanisms involving hyperuricaemia is the development of vascular damage. The aim of this study is to examine the role of hyperuricaemia on vascular function in patients with high cardiovascular risk.

METHODS AND RESULTS

We examined the clinical significance of hyperuricaemia in relation to vasomotor response of the brachial artery by using high-resolution ultrasound in 304 subjects with coronary artery disease and/or diabetes. Nitroglycerin-mediated dilatation (NMD) was significantly lower in the hyperuricaemic group compared with the normouricaemic group (12.8 ± 6.9% vs. 16.2 ± 7.7%, p < 0.001), but no significant difference was observed in flow-mediated dilatation (FMD) between the two groups [3.78 (95% CR: 1.5-9.9) vs. 3.88 (95% CR: -2.6 to 9.9), p = 0.78]. Multivariate analysis demonstrated that smoking was the strongest predictor of FMD (b = -0.81, p = 0.02); and that smoking (b = -2.62, p = 0.003), SBP (b = -0.11, p = 0.001), hyperuricaemia (b = -2.11, p = 0.02) and use of nitrates (b = -3.30, p = 0.001) were independent predictors of NMD.

CONCLUSION

High cardiovascular risk patients with hyperuricaemia had a lower NMD than those with normouricaemia. Importantly, hyperuricaemia was independently associated with NMD after multivariable adjustments. To further understand the pathophysiological mechanisms involving hyperuricaemia, particularly in the context of impaired NMD, further experimental and clinical studies are needed.

Pioglitazone and Endothelial Dysfunction: Pleiotropic Effects and Possible Therapeutic Implications

The vascular endothelium has a central role in the modulation of vascular tone with associated antioxidant, anti-inflammatory, pro-fibrinolytic, anti-adhesive, and anticoagulant effects. This is primarily accomplished by the timely release of endothelial autacoids. On the other hand, endothelial dysfunction (ED) provoked by insulin resistance has been linked with reduced nitric oxide bioavailability, increased production of reactive oxygen species, and alterations of endothelial regeneration. Pioglitazone is classified as an insulin-sensitizing, anti-hyperglycemic agent. The mechanism of action associated with pioglitazone includes the activation of peroxisome proliferator-activated receptor-gamma with stable improvement in glycemic control in diabetic patients. Today, it is known that apart from the beneficial effects on glucose homeostasis, pioglitazone exerts several pleiotropic effects, including the improvement of ED. Thus, the aim of this article was to summarize the current knowledge related to signaling mechanisms of the pioglitazone-induced improvement or reversal of ED. The relevant clinical studies and possible therapeutic implications connected to pioglitazone-related action on the endothelium were analyzed too.

Endothelial dysfunction in metabolic and vascular disorders

Vascular endothelium has important regulatory functions in the cardiovascular system and a pivotal role in the maintenance of vascular health and metabolic homeostasis. It has long been recognized that endothelial dysfunction participates in the pathogenesis of atherosclerosis from early, preclinical lesions to advanced, thrombotic complications. In addition, endothelial dysfunction has been recently implicated in the development of insulin resistance and type 2 diabetes mellitus (T2DM). Considering that states of insulin resistance (eg, metabolic syndrome, impaired fasting glucose, impaired glucose tolerance, and T2DM) represent the most prevalent metabolic disorders and risk factors for atherosclerosis, it is of considerable scientific and clinical interest that both metabolic and vascular disorders have endothelial dysfunction as a common background. Importantly, endothelial dysfunction has been associated with adverse outcomes in patients with established cardiovascular disease, and a growing body of evidence indicates that endothelial dysfunction also imparts adverse prognosis in states of insulin resistance. In this review, we discuss the association of insulin resistance and T2DM with endothelial dysfunction and vascular disease, with a focus on the underlying mechanisms and prognostic implications of the endothelial dysfunction in metabolic and vascular disorders. We also address current therapeutic strategies for the improvement of endothelial dysfunction.