SEARCH · PubMed Health

Results for “endothelial dysfunction”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21Linked to original sources

PubMed2002

Effects of the superoxide dismutase-mimetic compound tempol on endothelial dysfunction in streptozotocin-induced diabetic rats.

Evidence exists to support the beneficial effects of superoxide dismutase on endothelial dysfunction induced by hyperglycemia in vitro. In vivo, however, studies of the effects of native superoxide dismutase preparations on the vascular complications accompanying diabetes are limited, and their therapeutic application potential has so far been disappointing. The objective of this study was to evaluate, for the first time in vivo, the effects of long-term administration of tempol, a stable superoxide dismutase-mimic compound, on diabetes-induced endothelial dysfunction in rats. Diabetes was induced by streptozotocin and rats were monitored for 8 weeks with or without treatment with tempol (100 mg/kg, s.c., b.i.d). Diabetic rats showed increased vascular levels of superoxide, which was accompanied by increased levels of the oxidative stress markers malondialdehyde and 8-epi-prostaglandin F(2alpha). In addition, the vasorelaxant as well as the cGMP-producing effects of acetylcholine and glyceryl trinitrate were reduced in diabetic rats. Treatment with tempol abolished not only the differences in the vascular content of superoxide, malondialdehyde and 8-epi-prostaglandin F(2alpha), but also the differences in the relaxation and cGMP responses of aortic rings to both acetylcholine and glyceryl trinitrate between control and diabetic rats. These results support the involvement of reactive oxygen species in mediation of hyperglycemia-induced endothelial dysfunction in vivo, and provide the rationale for potential utilization of stable superoxide dismutase-mimic nitroxides for the prevention of the vascular complications accompanying diabetes.

Acetylcholine↗

PubMed1996

Coronary angioplasty ameliorates hypoperfusion-induced endothelial dysfunction in patients with stable angina pectoris.

OBJECTIVES: This study sought to investigate the effect of coronary angioplasty on chronic hypoperfusion-induced endothelial dysfunction in patients with coronary heart disease. BACKGROUND: The endothelium is an important component for organ flow regulation. Ischemia with or without reperfusion is known to cause endothelial dysfunction. We tested the hypothesis that chronic hypoperfusion impairs endothelial function in the angiographically normal coronary artery segment distal to stenosis and that the impairment by chronic hypoperfusion is reduced by coronary angioplasty. METHODS: In 13 patients with stable angina pectoris, substance P (10, 30 and 100 pmol) and nitroglycerin (200 micrograms) were sequentially infused into the coronary artery in a cumulative manner on the day after coronary angioplasty. In 10 of these patients, vascular responses to these agents were again investigated 3 months after angioplasty. Changes in vascular diameter were evaluated in vessels located proximal and distal to the target lesion, both of which were angiographically normal, by performing computer-assisted quantitative coronary angiography. In five patients, the transstenotic pressure gradient was also measured with a pressure sensor-mounted guide wire before angioplasty. RESULTS: On the day after angioplasty, the magnitude of dilation by substance P in distal segments was significantly less than that in proximal segments and inversely correlated with the transstenotic pressure gradient (p < 0.05) and lesion stenosis (p < 0.05). There was no difference in nitroglycerin-induced vasodilation between the two vessel segment groups. Three months later, the impaired response to substance P in the distal segment was restored to normal. CONCLUSIONS: We conclude that chronic hypoperfusion impairs endothelium-dependent dilation of coronary artery distal to critical stenosis in patients with ischemic heart disease and that coronary angioplasty ameliorates the endothelial dysfunction within 3 months.

Aged↗

PubMed2006

[Obesity and endothelial dysfunction].

The endothelium plays a crucial role in modulating vascular function and structure. In healthy conditions, nitric oxide produced by endothelial cells exerts not only vasodilating properties, but also several other protective actions toward the vessel wall against the development of atherosclerosis and thrombosis. Traditional cardiovascular risk factors are characterized by endothelial dysfunction caused by an enhanced production of oxidative stress leading to destroy nitric oxide, thus reducing its availability. Abdominal obesity is associated with endothelial dysfunction, through direct mechanisms, such as insulin resistance and the association with risk factors (including diabetes mellitus, hypertension and dyslipidemia), and direct, by the production of adipokines and pro-inflammatory cytokines, which in turn induce oxidative stress leading to a reduced nitric oxide availability. A reduced endothelium-dependent relaxation is a predictor of cardiovascular events in high-risk patients and represents a putative clinical parameter to stratify the cardiovascular risk and a useful marker for therapy efficacy. Weight loss and a modification of lifestyle ameliorate endothelial function in obese patients, an effect due not only to a better glycemic profile, but also secondary to reduced plasma levels of inflammatory markers and adipokines. At present, whether an improvement of endothelial dysfunction secondary to weight loss is significantly associated with a better cardiovascular prognosis is still unknown. (G Ital Cardiol 2006; 7 (11): 715-723)

Cytokines↗

PubMed2004

Endothelial nitric oxide synthase and methylenetetrahydrofolate reductase gene polymorphisms are associated with endothelial dysfunction in young, healthy men.

BACKGROUND: The guanine to thymine polymorphism at position 894 of the eNOS gene (resulting in a change from glutamate to aspartate [Asp] at codon 298 [Asp298]) and the methylenetetrahydrofolate reductase (MTHFR) gene polymorphism (C677T) have been reported to be associated with atherosclerosis and cardiovascular disease. Endothelial dysfunction is considered to be the earliest stage of atherosclerosis. OBJECTIVES: To examine whether common eNOS and MTHFR gene polymorphisms are associated with endothelial dysfunction in young, healthy men without overt cardiovascular disease. SUBJECTS AND METHODS: Flow-mediated, endothelium-dependent vasodilation (FMD) and glyceryl trinitrate-induced, endothelium-independent vasodilation (GTN) were measured using high-resolution ultrasound of the brachial artery in 53 young, healthy men assigned to eNOS and MTHFR genotypes. RESULTS: Subjects with the eNOS Asp298 allele (n=15) showed significantly reduced FMD:GTN compared with those without this allele (n=38) (0.23+/-0.13 [mean +/- SD] versus 0.35+/-0.14, P=0.0072), whereas there was no significant difference in GTN between these two groups. Although subjects with the MTHFR T677 allele did not show significantly reduced levels of FMD:GTN, subjects with the eNOS Asp298 allele and who were carriers of the MTHFR T677 allele demonstrated markedly reduced levels of FMD:GTN compared with noncarriers (0.14+/-0.05 versus 0.28+/-0.13, P=0.04). CONCLUSIONS: The data suggest that even in young men, the eNOS Asp298 allele may be involved in endothelial dysfunction before any overt vascular disease has occurred. Furthermore, a combination of the eNOS Asp298 and MTHFR T677 alleles may exaggerate endothelial dysfunction and may contribute to a comparatively earlier development of atherosclerosis.

Adult↗

PubMed1997

Endothelial dysfunction: cause of the insulin resistance syndrome.

Insulin resistance has been proposed as the metabolic basis of atherogenesis. This hypothesis is based on the concept of the "insulin resistance syndrome," according to which insulin resistance is viewed as the primary abnormality that gives rise to dyslipidemia, essential hypertension, impaired glucose tolerance, and NIDDM. However, this hypothesis takes no account of the well-established and central role of vascular endothelium in the atherogenic process. Although endothelial injury is an early and prominent feature of atherogenesis, relatively little attention has been given to its metabolic consequences. In subjects with NIDDM, we have shown that endothelial dysfunction is associated with insulin resistance, raising the question of whether this relationship could be causal. In this article, we review the factors that are considered to be responsible for the development of endothelial dysfunction during atherogenesis, together with the metabolic consequences of endothelial dysfunction. While dysfunction of the endothelium in large and medium-sized arteries plays a central role in atherogenesis, we argue that dysfunction of peripheral vascular endothelium, at arteriolar and capillary level, plays the primary role in the pathogenesis of both insulin resistance and the associated features of the insulin resistance syndrome. We propose that the insulin resistance syndrome, together with many aspects of atherogenesis, can be viewed as the diverse consequences of endothelial dysfunction in different vascular beds. This new and testable hypothesis accounts for both the endothelial and metabolic abnormalities associated with atherogenesis.

Animals↗

PubMed2003

Impaired activities of antioxidant enzymes elicit endothelial dysfunction in spontaneous hypertensive rats despite enhanced vascular nitric oxide generation.

OBJECTIVE: Enhanced oxidative stress is involved in mediating the endothelial dysfunction associated with hypertension. The aim of this study was to investigate the relative contributions of pro-oxidant and anti-oxidant enzymes to the pathogenesis of endothelial dysfunction in genetic hypertension. METHODS: Dilator responses to endothelium-dependent and endothelium-independent agents such as acetylcholine (ACh) and sodium nitroprusside were measured in the thoracic aortas of 28-week-old spontaneously hypertensive rats (SHR) and their matched normotensive counterparts, Wistar Kyoto rats (WKY). The activity and expression (mRNA and protein levels) of endothelial nitric oxide synthase (eNOS), p22-phox, a membrane-bound component of NAD(P)H oxidase, and antioxidant enzymes, namely, superoxide dismutases (CuZn- and Mn-SOD), catalase and glutathione peroxidase (GPx), were also investigated in aortic rings. RESULTS: Relaxant responses to ACh were attenuated in phenylephrine-precontracted SHR aortic rings, despite a 2-fold increase in eNOS expression and activity. Although the activity and/or expression of SODs, NAD(P)H oxidase (p22-phox) and GPx were elevated in SHR aorta, catalase activity and expression remained unchanged compared to WKY. Pretreatment of SHR aortic rings with the inhibitor of xanthine oxidase, allopurinol, and the inhibitor of cyclooxygenase, indomethacin, significantly potentiated ACh-induced relaxation. Pretreatment of SHR rings with catalase and Tiron, a superoxide anion (O(2)(-)) scavenger, increased the relaxant responses to the levels observed in WKY rings whereas pyrogallol, a O(2)(-)-generator, abolished relaxant responses to ACh. CONCLUSION: These data demonstrate that dysregulation of several enzymes, resulting in oxidative stress, contributes to the pathogenesis of endothelial dysfunction in SHR and indicate that the antioxidant enzyme catalase is of particular importance in the reversal of this defect.

Acetylcholine↗

PubMed1992

Endothelial dysfunction in patients with chest pain and normal coronary arteries.

BACKGROUND: A subgroup of patients with chest pain and angiographically normal epicardial coronary arteries have reduced dilator response to metabolic or pharmacological stimuli, but the mechanisms responsible for this reduced dilator response are unknown. In this study, we have investigated whether microvascular endothelial dysfunction is a cause of the observed reduced vasodilator reserve. METHODS AND RESULTS: The functional response of the microvasculature was studied with rapid atrial pacing at 150 beats per minute. Fifty-one patients, 20 hypertensive and 31 normotensive, with chest pain and normal epicardial coronary arteries (< 10% stenosis) were studied. Endothelial function was tested with incremental infusions of acetylcholine to achieve estimated intracoronary concentrations ranging from 10(-7) M to 10(-5) M. Endothelium-independent smooth muscle vasomotion was measured using intracoronary sodium nitroprusside. Endothelial dysfunction of epicardial coronary arteries, demonstrated as severe (> 50%) constriction with < 10(-5) M acetylcholine concentration, was evident in five patients (10%). In the remaining 46 patients, coronary blood flow increased with acetylcholine (mean, 78 +/- 43%) and atrial pacing (mean, 51 +/- 37%), and coronary vascular resistance decreased by 35 +/- 16% and 29 +/- 14%, respectively, but the responses were heterogeneous. There was a correlation between the coronary resistance change with acetylcholine and the change with atrial pacing: r = 0.68, p < 0.001 in these 46 patients. Thus, patients with depressed dilation with atrial pacing had reduced endothelium-dependent dilation with acetylcholine, and vice versa. However, the microvascular dilation caused by sodium nitroprusside was not significantly different between patients with and those without reduced dilation with atrial pacing, indicating that the vasodilator defect was not caused by smooth muscle dysfunction. There were no differences in the vasodilator responses with atrial pacing, acetylcholine, or nitroprusside between normotensive and hypertensive patients. Multivariate regression analysis was performed to determine whether age, sex, serum cholesterol level, hypertension, presence of mild epicardial vessel atherosclerosis, resting left ventricular function, change in left ventricular ejection fraction with exercise, vasodilation with acetylcholine, and vasodilation with sodium nitroprusside were independently related to the vasodilator response to atrial pacing. Only the change in coronary vascular resistance with acetylcholine was independently correlated with the change in resistance with atrial pacing: R2 = 0.46, p < 0.0001. CONCLUSIONS: Patients with chest pain, normal epicardial coronary arteries, and reduced vasodilation in response to atrial pacing appear to have associated endothelial dysfunction of the coronary microvasculature. Thus, microvascular endothelial dysfunction may contribute to the reduced vasodilator reserve with atrial pacing and anginal chest pain in these patients.

Acetylcholine↗

PubMed2002

[Is mild essential hypertension without obvious organ complications and risk factors associated with increased levels of circulating markers of endothelial dysfunction? Effect of ACE inhibitor therapy].

The objective of the investigation was to assess whether circulating adhesion molecules, von Willebrand factor (vWf) and endothelin-1 are elevated in patients with mild uncomplicated essential hypertension without further risk factors of atherosclerosis and whether they could serve as indicators of endothelial dysfunction in this form of hypertension. Furthermore the authors investigated the effect of ACE inhibitor treatment (ACEI), quinapril, on the level of these markers of endothelial dysfunction. The level of adhesion molecules [intercellular cytoadhesion molecule-1 (ICAM-1), E-selectin, P-selectin], von Willebrand s factor (vWf) and endothelin-1 were assessed in patients with mild essential hypertension without further cardiovascular risk factors or clinical manifestations of atherosclerosis before and after quinapril treatment (n = 25) and compared with normotensive controls (n = 29). The results of the examinations provided evidence that contrary to controls the hypertensive subjects had significantly higher ICAM-1 levels (237.8 vs. 207.8 ng/ml, P = 0.02) vWf (118 vs. 106 IU/dl, p < 0.05) and endothelin-1 (5.81 vs. 5.15 fmol/ml, p < 0.05). Three-month treatment of hypertensive patients with ACEI led to a significant drop of endothelin-1 levels (5.81 vs. 5.26 fmol/ml, p = 0.01). The authors proved also an unequivocal declining trend of other cytoadhesion molecules and vWf after ACEI treatment, the changes however were not statistically significant. From the investigation it may be concluded that also patients with uncomplicated essential hypertension without other cardiovascular risk factors or clinical manifestations of atherosclerosis have significantly elevated plasma levels of ICAM-1, vWf and endothelin-1. Higher concentrations of these factors suggest endothelial dysfunction already in mild forms of essential hypertension without further risk factors or cardiovascular complications. A significant drop of endothelin-1 and declining trend of the other investigated indicators suggest that ACEI treatment can favourably influence endothelial dysfunction in hypertensive patients also independently on reduction of the BP.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2003

Decreased platelet activation and endothelial dysfunction after percutaneous mitral balloon valvuloplasty.

OBJECTIVE: This study was conducted to assess the changes in platelet activation and endothelial dysfunction in patients with mitral stenosis (MS) and sinus rhythm (SR) following percutaneous mitral balloon valvuloplasty (PMBV). BACKGROUND: Systemic thromboembolism is a serious complication in patients with valvular heart disease, and its incidence is highest in those with mitral stenosis. A hypercoagulable state has also been reported in patients with mitral stenosis and sinus rhythm. A recent study has shown that patients with previous PMBV had a lower incidence of thromboembolism. METHODS AND RESULTS: The study was conducted in 21 patients (two men, 19 women, mean age=34+/-6 years) with mitral stenosis and sinus rhythm (SR) who underwent percutaneous mitral balloon valvuloplasty and 17 healthy control subjects (two men, 15 women, mean age=33+/-6 years). Biochemical markers of platelet activity (beta thromboglobulin, BTG, and soluble P-selectin, sPsel) and endothelial dysfunction (von Willebrand Factor, vWF) were measured in both control subjects' and patients' serum samples taken immediately before PMBV and 24 h after PMBV procedure. All patients underwent successful PMBV. Significant improvement of mitral valve area, pulmonary artery pressure, mean mitral gradients, and left atrial diameter were achieved in all patients after PMBV. Compared with control subjects, patients with MS had higher plasma levels of BTG (66+/-26 ng/ml vs. 14+/-6 ng/ml, P<0.001), vWF (177+/-67 units/dl vs. 99+/-37 units/dl, P<0.0001), sPsel (226+/-74 ng/ml vs. 155+/-66 ng/ml, P<0.001). There was a significant reduction of plasma levels of BTG (66+/-26 ng/ml vs. 48+/-20 ng/ml, P=0.002), vWF (177+/-67 units/dl vs. 134+/-60 units/dl, P=0.001) and P-selectin (226+/-74 ng/ml vs. 173+/-71 ng/ml, P=0.008,) 24 h after PMBV. CONCLUSION: We have shown that patients with severe MS and SR have increased platelet activation and endothelial dysfunction compared with control subjects and PMBV results in decreased platelet activity and improvement of endothelial injury.

Adult↗

PubMed2005

Endothelial dysfunction in childhood infection.

BACKGROUND: Atherosclerosis begins in early life, and endothelial dysfunction is recognized as a key initiating event in the development of atherosclerosis. Although infection has been implicated in endothelial dysfunction and atherogenesis, the impact of acute common childhood infections on the vascular endothelium is unknown. METHODS AND RESULTS: We studied 600 children aged 10 years drawn from the Avon Longitudinal Study of Parents and Children. The children were divided into 3 groups: those with current acute infection (AI; n=135; 73 boys and 62 girls); a convalescent group with infection in the past 2 weeks (n=166; 78 boys and 88 girls), and a healthy control group (n=299; 131 boys and 168 girls). Endothelial function was determined in all subjects by high-resolution ultrasound to measure brachial artery flow-mediated dilation (FMD) and was expressed as the percentage change in diameter from baseline after reactive hyperemia. FMD was repeated in 40 children in the AI group and 50 in the control group after a mean interval of 1 year. FMD was lower in both the AI group (6.3+/-2.7%, mean+/-SD) and the convalescent group (8.1+/-3.1%) than in the control group (9.7+/-2.5%; P<0.001 for both). The observed differences in FMD remained after adjustment for potential confounding variables. At the repeat visit, FMD was unchanged in controls (P=0.85) but improved in the AI group (P<0.001). CONCLUSIONS: Acute infection in childhood is associated with impaired endothelium-dependent vasodilation. These findings support a potential role for previously unsuspected extrinsic inflammatory stimuli in the pathogenesis of early atherosclerosis.

Arteriosclerosis↗

PubMed2004

Homocysteine-lowering treatment with folic acid, cobalamin, and pyridoxine does not reduce blood markers of inflammation, endothelial dysfunction, or hypercoagulability in patients with previous transient ischemic attack or stroke: a randomized substudy of the VITATOPS trial.

BACKGROUND AND PURPOSE: Epidemiological and laboratory studies suggest that increasing concentrations of plasma homocysteine (total homocysteine [tHcy]) accelerate cardiovascular disease by promoting vascular inflammation, endothelial dysfunction, and hypercoagulability. METHODS: We conducted a randomized controlled trial in 285 patients with recent transient ischemic attack or stroke to examine the effect of lowering tHcy with folic acid 2 mg, vitamin B12 0.5 mg, and vitamin B6 25 mg compared with placebo on laboratory markers of vascular inflammation, endothelial dysfunction, and hypercoagulability. RESULTS: At 6 months after randomization, there was no significant difference in blood concentrations of markers of vascular inflammation (high-sensitivity C-reactive protein [P=0.32]; soluble CD40L [P=0.33]; IL-6 [P=0.77]), endothelial dysfunction (vascular cell adhesion molecule-1 [P=0.27]; intercellular adhesion molecule-1 [P=0.08]; von Willebrand factor [P=0.92]), and hypercoagulability (P-selectin [P=0.33]; prothrombin fragment 1 and 2 [P=0.81]; D-dimer [P=0.88]) among patients assigned vitamin therapy compared with placebo despite a 3.7-micromol/L (95% CI, 2.7 to 4.7) reduction in total homocysteine (tHcy). CONCLUSIONS: Lowering tHcy by 3.7 micromol/L with folic acid-based multivitamin therapy does not significantly reduce blood concentrations of the biomarkers of inflammation, endothelial dysfunction, or hypercoagulability measured in our study. The possible explanations for our findings are: (1) these biomarkers are not sensitive to the effects of lowering tHcy (eg, multiple risk factor interventions may be required); (2) elevated tHcy causes cardiovascular disease by mechanisms other than the biomarkers measured; or (3) elevated tHcy is a noncausal marker of increased vascular risk.

Biomarkers↗

PubMed2005

Enhanced coronary calcification determined by electron beam CT is strongly related to endothelial dysfunction in patients with suspected coronary artery disease.

BACKGROUND: Coronary artery calcification determined by electron beam CT (EBCT) is strongly associated with total plaque burden but is not related to systemic vascular inflammation. AIMS: We sought to test the hypothesis that enhanced coronary artery calcification, a marker of atherosclerosis and plaque burden, was related to endothelial dysfunction in patients with suspected coronary artery disease (CAD). METHODS AND RESULTS: One hundred twenty-four subjects with suspected CAD were enrolled. Coronary artery calcification was detected by EBCT. A noninvasive method of brachial ultrasound was used to measure endothelium-dependent flow-mediated vasodilation (FMD) and endothelium-independent nitroglycerin-mediated vasodilation (NMD). Serum high-sensitivity C-reactive protein (hsCRP) and monocyte chemoattractant protein-1 (MCP-1) levels were also determined. Of the 124 patients, the calcium scores ranged from 0 to 4,394. All subjects were classified into three groups according to coronary calcium scores: group 1, score 0 (n = 26); group 2, scores 1 to 199 (n = 50); group 3, scores > or = 200 (n = 48). There was an inverse association between the degree of coronary artery calcification and the endothelium-dependent FMD in the three groups (6.9 +/- 0.6% vs 5.3 +/- 0.3% vs 3.7 +/- 0.3%, respectively; p < 0.001) but not the endothelium-independent NMD. Besides, no significant difference in serum levels of hsCRP and MCP-1 were found among the three groups. However, both the serum levels of hsCRP and MCP-1 were correlated significantly with endothelium-dependent FMD (r = - 0.211, p = 0.019; and r = - 0.188, p = 0.037, respectively). By multivariate analysis, enhanced coronary calcification was a strong independent predictor of endothelial dysfunction (p < 0.001). CONCLUSION: Enhanced coronary artery calcification strongly predicted endothelial dysfunction in patients with suspected CAD. Also, serum levels of hsCRP and MCP-1 were significantly correlated with endothelial function. These findings suggested that both calcium deposition and inflammation were involved in endothelial dysfunction.

Aged↗

PubMed1997

Endothelial dysfunction in a rat model of endotoxic shock. Importance of the activation of poly (ADP-ribose) synthetase by peroxynitrite.

DNA single strand breakage and activation of the nuclear enzyme poly (ADP-ribose) synthetase (PARS) contribute to peroxynitrite-induced cellular injury. We investigated the role of PARS activation in the pathogenesis of endothelial dysfunction. In human umbilical vein endothelial cells (HUVEC), DNA strand breakage (alkaline unwinding assay), PARS activation (incorporation or radiolabeled NAD+ into proteins), mitochondrial respiration [conversion of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide to formazan] and apoptotic index (cytoplasmatic release of histones) were measured. Endotoxin shock was induced in rats by bacterial lipopolysaccharide. Vascular reactivity of thoracic aortic rings were measured in organ chambers. In HUVEC, peroxynitrite caused a dose-dependent suppression of mitochondrial respiration, induced DNA strand breakage and caused an activation of PARS. Pharmacological inhibition of PARS reduced the acute and delayed suppression of mitochondrial respiration when cells were exposed to intermediate, but not high doses of peroxynitrite. Similarly, protection against the intermediate, but not high doses of peroxynitrite was seen in fibroblasts from the PARS-/- mice, when compared to wild-type controls. These data suggest that PARS plays a role in peroxynitrite-induced cytotoxicity, but at very high levels of oxidant exposure, PARS-independent cytotoxic mechanisms become predominant. Peroxynitrite-induced apoptosis was not affected by PARS inhibition. Vascular rings exposed to peroxynitrite and rings taken from rats subjected to endotoxic shock exhibited reduced endothelium-dependent relaxant responses in response to acetylcholine. The development of this endothelial dysfunction was ameliorated by the PARS inhibitor 3-aminobenzamide. Activation of PARS by peroxynitrite, therefore, may be involved in the development of endothelial dysfunction in endotoxemia.

Animals↗

PubMedDate not supplied

Diabetic endothelial dysfunction: effect of free radical scavenging in Type 2 diabetic patients.

Diabetes mellitus is characterized by oxidative stress, which in turn determines endothelial dysfunction. It has been recently demonstrated that gliclazide, a second-generation sulfonylurea with antioxidant properties, is able to protect endothelial function in animal models of diabetes. In streptozotocin-induced diabetic rats, gliclazide prevented endothelial dysfunction when given orally and improved the impaired relaxations to exogenous nitric oxide (NO) when applied on aortic segments. Moreover, gliclazide was able to inhibit glycosylated oxyhemoglobin-induced endothelial dysfunction both in animal and human microvessels. All these effects were not shared by glibenclamide, but were mimicked by vitamin C or superoxide dismutase (SOD), thus suggesting that gliclazide's action on endothelium-dependent vasodilation is mediated by its antioxidant properties. Thus far, there are no clinical studies that describe the influence of gliclazide on both oxidative status and NO-mediated vasodilation. We therefore evaluated the effects of gliclazide on plasma lipid peroxides, plasma total radical trapping antioxidant parameter (TRAP), and NO-mediated vasodilation assessed by blood pressure modifications following intravenous L-arginine in 30 subjects with Type 2 diabetes mellitus. The patients received glibenclamide (n=15) or gliclazide (n=15) in a 12-week, randomized, observer-blinded, parallel study, and were studied pre- and post-treatment. At 12 weeks, gliclazide-treated patients had lower plasma lipid peroxides (13.3+/-3.8 vs. 19.2+/-4.3 micromol/l; P=.0001, respectively) and higher plasma TRAP (1155.6+/-143.0 vs. 957.7+/-104.3 micromol/l; P=.0001, respectively) than the glibenclamide-treated patients. Gliclazide, but not glibenclamide, significantly reduced the systolic and diastolic blood pressure (P=.0199 and P=.00199, respectively, two-way repeated-measures analysis of variance) in response to intravenous L-arginine. In conclusion, our results demonstrate that glicazide treatment improves both antioxidant status and NO-mediated vasodilation in diabetic patients.

Adult↗

PubMed2000

Vasodilator-stimulated phosphoprotein serine 239 phosphorylation as a sensitive monitor of defective nitric oxide/cGMP signaling and endothelial dysfunction.

Studies with cGMP-dependent protein kinase I (cGK-I)-deficient human cells and mice demonstrated that cGK-I ablation completely disrupts the NO/cGMP pathway in vascular tissue, which indicates a key role of this protein kinase as a mediator of the NO/cGMP action. Analysis of the vasodilator-stimulated phosphoprotein phosphorylated at serine 239 (P-VASP) is a useful tool to monitor cGK-I activation in platelets and cultured endothelial and smooth muscle cells. Therefore, we investigated whether endothelial dysfunction and/or vascular NO bioavailability is reflected by decreased vessel wall P-VASP and whether improvement of endothelial dysfunction restores this P-VASP. Incubation of aortic tissue from New Zealand White Rabbits with the NOS inhibitor N:(G)-nitro-Ld-arginine and endothelial removal strikingly reduced P-VASP. Oxidative stress induced by inhibition of CuZn superoxide dismutase increased superoxide and decreased P-VASP. Endothelial dysfunction in hyperlipidemic Watanabe rabbits (WHHL) was associated with increased vascular superoxide and with decreased P-VASP. Treatment of WHHL with AT(1) receptor blockade improved endothelial dysfunction, reduced vascular superoxide, increased vascular NO bioavailability, and increased P-VASP. Therefore, the level of vessel P-VASP closely follows changes in endothelial function and vascular oxidative stress. P-VASP is suggested to represent a novel biochemical marker for monitoring the NO-stimulated sGC/cGK-I pathway and endothelial integrity in vascular tissue.

Angiotensin Receptor Antagonists↗

PubMed2006

AT1-receptor blockade with irbesartan improves peripheral but not coronary endothelial dysfunction in patients with stable coronary artery disease.

Activation of the renin-angiotensin-aldosterone system plays an important role in the pathogenesis of endothelial dysfunction and atherosclerosis. Studies evaluating the effect of AT1-receptor blockers on endothelial dysfunction in patients with coronary artery disease (CAD) revealed mixed results. Studies addressing the effects of AT1-receptor blockers on the coronary and peripheral function in the same study population, are still lacking. We therefore aimed to test the effects of long-term therapy with the AT1-receptor blocker irbesartan (IRB) on both, the coronary and peripheral endothelial function in patients with CAD. Seventy-two patients with CAD were randomly assigned to double-blinded treatment for 6 months with IRB 300 mg per day or placebo, respectively. Coronary and peripheral endothelial function were measured by intracoronary infusion of acetylcholine (final intracoronary concentration 10(-7.3) to 10(-5.6)M) and by determining flow-dependent dilation (FMD) of the brachial artery, respectively. IRB significantly improved FMD, while no change of coronary endothelial function was observed. Interestingly, plasma levels of N(G),N(G)-dimethyl-arginine, and the isoprostane excretion rate were not modified. IRB treatment improves peripheral but not coronary endothelial dysfunction in patients with CAD. Since reduced FMD of the brachial artery has been shown to be associated with a high-cardiovascular event rate, improvement of FMD by IRB may lead to better prognosis of patients with CAD.

Angiotensin II Type 1 Receptor Blockers↗

PubMed2006

Endothelial dysfunction and low-grade inflammation explain much of the excess cardiovascular mortality in individuals with type 2 diabetes: the Hoorn Study.

OBJECTIVE: The mechanisms responsible for the increased cardiovascular disease risk that accompanies type 2 diabetes (T2D) remain poorly understood. It is commonly held that endothelial dysfunction and low-grade inflammation can explain, at least in part, why deteriorating glucose tolerance is associated with cardiovascular disease. However, there is no direct evidence for this contention. METHODS AND RESULTS: In this population-based study (n=631), T2D was cross-sectionally associated with both endothelial dysfunction and low-grade inflammation, whereas impaired glucose metabolism (IGM) was associated only with low-grade inflammation. These findings were independent of other risk factors that accompany T2D or IGM. During a follow-up of 11.7 years (median; range 0.5 to 13.2 years), low-grade inflammation was associated with a greater risk of cardiovascular mortality (hazard ratio, 1.43 [95% CI, 1.17 to 1.77] per 1 SD difference). For endothelial dysfunction, the association with cardiovascular mortality was stronger in diabetic (hazard ratio, 1.87 [95% CI, 1.43 to 2.45]) than in nondiabetic individuals (hazard ratio, 1.23 [95% CI, 0.86 to 1.75]; P interaction=0.06). Finally, T2D-associated endothelial dysfunction and low-grade inflammation explained approximately 43% of the increase in cardiovascular mortality risk conferred by T2D. CONCLUSIONS: These data emphasize the necessity of randomized controlled trials of strategies that aim to decrease cardiovascular disease risk by improving endothelial function and decreasing low-grade inflammation, especially for T2D patients.

Aged↗

PubMed2005

Non-alcoholic hepatic steatosis and its relation to increased plasma biomarkers of inflammation and endothelial dysfunction in non-diabetic men. Role of visceral adipose tissue.

AIMS: To compare plasma biomarkers of inflammation and endothelial dysfunction in individuals with and without non-alcoholic hepatic steatosis (HS), and to evaluate whether such differences were mediated by the adverse metabolic pattern, typically found in these subjects. METHODS: HS (by ultrasound and computed tomography), visceral fat (by computed tomography), insulin resistance (by homeostasis model assessment-HOMA), plasma biomarkers of inflammation and endothelial dysfunction (hs-C reactive protein, fibrinogen, von Willebrand factor, plasminogen activator inhibitor-1 activity) were measured in 100 non-smoking, healthy, male volunteers. RESULTS: Plasma hs-CRP, fibrinogen, v-WF and plasminogen activator inhibitor-1 (PAI-1) activity levels were markedly higher (P < 0.01 or less) in subjects with non-alcoholic HS (n = 35) than in those without HS (n = 65). The former also had significantly higher values for body mass index (BMI), visceral fat, diastolic blood pressure, HOMA insulin resistance score, plasma insulin (both fasting and after glucose load), triglycerides, liver enzymes, and lower high-density lipoprotein (HDL)-cholesterol concentration. While the marked differences in these pro-inflammatory biomarkers observed between the groups were little affected by adjustment for age, BMI, blood pressure values, HOMA insulin resistance score, plasma triglyceride and liver enzyme concentrations, they were completely abolished after controlling for visceral fat. Similarly, in multivariate regression analyses, increased visceral fat significantly predicted the pro-inflammatory biomarkers, independently of HS and other potential confounders. CONCLUSIONS: These results indicate that, in non-smoking, non-diabetic men, the significant increase of plasma biomarkers of inflammation and endothelial dysfunction in the presence of non-alcoholic HS is largely mediated by abdominal visceral fat accumulation.

Adipose Tissue↗