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Treatment of obstructive sleep apnoea leads to improved microvascular endothelial function in the systemic circulation.

BACKGROUND: Obstructive sleep apnoea (OSA) is a common and potentially reversible cause of systemic hypertension. The mechanisms whereby OSA leads to hypertension and the effects of treatment on arterial function, however, are not well established. Microvascular arterial endothelial and smooth muscle function was assessed in subjects with OSA before and after treatment with continuous positive airways pressure (CPAP). METHODS: Ten subjects of mean (SE) age 49 (8) years with at least moderately severe OSA had detailed forearm vascular reactivity studies before and after 3 months of CPAP treatment. The systemic circulation was assessed by measuring brachial artery pressure, flow and resistance responses to intra-arterial infusions of acetylcholine (ACh; an endothelium dependent vasodilator), sodium nitroprusside (SNP; an endothelium independent vasodilator), L-NMMA (a nitric oxide (NO) antagonist), and L-arginine (the substrate for NO). RESULTS: Before CPAP, ACh and SNP infusions increased forearm blood flow in a dose dependent manner (p<0.01). After CPAP, endothelium dependent dilation to ACh was significantly increased (434 (23)% of baseline after CPAP v 278 (20)% before CPAP, p<0.001), whereas SNP induced dilation was unchanged. Resting NO production was higher after CPAP, evidenced by a significantly greater reduction in basal flow by L-NMMA (p=0.05). L-Arginine reversed the effect of L-NMMA in all cases. CONCLUSION: In patients with OSA, treatment with CPAP improves baseline endothelial NO release and stimulates endothelium dependent vasorelaxation in the systemic circulation. This is a potential mechanism for improving systemic and vascular function in patients with OSA treated with CPAP.

Analysis of Variance↗

Lifestyle modification and endothelial function in obese subjects.

The metabolic syndrome is a cluster of metabolic and vascular abnormalities that include central obesity, insulin resistance, hyperinsulinemia, glucose intolerance, hypertension, dyslipidemia, hypercoagulability and an increased risk of coronary and cerebral vascular disease. These metabolic and vascular abnormalities are the main cause of cardiovascular mortality in western societies. Endothelial dysfunction, an early step in the development of atherosclerosis, has been reported in obese nondiabetic individuals and in patients with Type 2 diabetes. It has also been observed in individuals at high risk for Type 2 diabetes, including those with impaired glucose tolerance and the normoglycemic first-degree relatives of Type 2 diabetic patients. Recent evidence points to adipocytes as a complex and active endocrine tissue whose secretory products, including free fatty acids and several cytokines (i.e., leptin, adiponectin, tissue necrosis factor-alpha, interleukin-6, and resistin) play a major role in the regulation of human metabolic and vascular biology. These adipocytokines have been claimed to be the missing link between insulin resistance and cardiovascular disease. Interventions designed to improve endothelial and/or adipose-tissue functions may reduce cardiovascular events in obese individuals with either the metabolic syndrome or Type 2 diabetes. Lifestyle modification in the form of caloric restriction and increased physical activity are the most common modalities used for treating those individuals at risk and is unanimously agreed to be the initial step in managing Type 2 diabetes. Several recent studies have demonstrated favorable impacts of lifestyle modifications in improving endothelial function and insulin sensitivity, in addition to altering serum levels of adipocytokines and possibly reducing cardiovascular events. This review discusses current knowledge of the role of lifestyle modifications in ameliorating cardiovascular risk in obese subjects with either the metabolic syndrome or Type 2 diabetes.

Adipose Tissue↗

Myoseverin is a potential angiogenesis inhibitor by inhibiting endothelial cell function and endothelial progenitor cell differentiation.

Myoseverin, a new microtubule-binding molecule, acts reversibly on myoblast proliferation without the cytotoxic effects displayed by nonpurine-based microtubule-disrupting molecules, like taxol, vinblastine, nocodazole, and the colchicines. In this study, we examined the effects of myoseverin on in vitro function of endothelial cells and endothelial progenitor cell differentiation in order to explore the possibility for the application of myoseverin as a reversible antiangiogenic agent. Myoseverin potently inhibited proliferation of human umbilical vein endothelial cells (HUVECs) in a dose-dependent manner with an IC50 of approximately 8 microM. When myoseverin was removed after treatment for 3 days, all the cells pretreated at a concentration range of 2.5-80 microM resumed the cell growth. It also inhibited VEGF-induced HUVEC migration dose dependently. When mononuclear cells (MNCs) isolated from human cord blood were cultured on fibronectin-coated plates for 7 days, myoseverin decreased the number of adherent cells in a dose-dependent manner with IC50 of approximately 9 microM. It also suppressed the development of ac-LDL uptake ability as well as the expression of endothelial lineage markers, KDR, CD31, and vWF. Finally, it inhibited formation of HUVECs or ex vivo cultivated EPCs into capillary-like structure on Matri-gel and in vivo angiogenesis on the chick chorioallantoic membrane. Therefore, these results suggest that myoseverin can be effectively used for the inhibition of new vessel growth by inhibiting endothelial cell function and differentiation of progenitor cells.

Angiogenesis Inhibitors↗

Plaque-prone hemodynamics impair endothelial function in pig carotid arteries.

Hemodynamic forces play an active role in vascular pathologies, particularly in relation to the localization of atherosclerotic lesions. It has been established that low shear stress combined with cyclic reversal of flow direction (oscillatory shear stress) affects the endothelial cells and may lead to an initiation of plaque development. The aim of the study was to analyze the effect of hemodynamic conditions in arterial segments perfused in vitro in the absence of other stimuli. Left common porcine carotid segments were mounted into an ex vivo arterial support system and perfused for 3 days under unidirectional high and low shear stress (6 +/- 3 and 0.3 +/- 0.1 dyn/cm(2)) and oscillatory shear stress (0.3 +/- 3 dyn/cm(2)). Bradykinin-induced vasorelaxation was drastically decreased in arteries exposed to oscillatory shear stress compared with unidirectional shear stress. Impaired nitric oxide-mediated vasodilation was correlated to changes in both endothelial nitric oxide synthase (eNOS) gene expression and activation in response to bradykinin treatment. This study determined the flow-mediated effects on native tissue perfused with physiologically relevant flows and supports the hypothesis that oscillatory shear stress is a determinant factor in early stages of atherosclerosis. Indeed, oscillatory shear stress induces an endothelial dysfunction, whereas unidirectional shear stress preserves the function of endothelial cells. Endothelial dysfunction is directly mediated by a downregulation of eNOS gene expression and activation; consequently, a decrease of nitric oxide production and/or bioavailability occurs.

Animals↗

Improvement of endothelial function by systemic transfusion of vascular progenitor cells.

Endothelial dysfunction is characterized by abnormalities in vasoreactivity and is a marker of the extent of atherosclerosis. Cellular repair by circulating progenitor cells of ongoing vascular injury may be essential for vascular integrity and function and may limit abnormalities in vasoreactivity. Apolipoprotein E-deficient (apoE-/-) mice were splenectomized and treated with high-cholesterol diet for 5 weeks, resulting in marked impairment of endothelium-dependent vasodilation of aortic segments as compared with wild-type mice. Intravenous transfusion of 2x10(7) spleen-derived mononuclear cells (MNCs) isolated from wild-type mice on 3 consecutive days restored endothelium-dependent vasodilation in the apoE-/- mice, as measured 7, 14, and 45 days after transfusion. Histological analyses of aortic tissue identified fluorescent-labeled, exogenously applied progenitor cells that expressed the endothelial cell marker CD31 in the endothelial cell layer of atherosclerotic lesions. Progenitor cell treatment led to increased vascular nitric oxide synthase activity. Transfusion of either in vitro-differentiated Dil-Ac-LDL/lectin-positive endothelial progenitor cells, CD11b-positive (monocyte marker), CD45R-positive (B-cell marker), or Sca-1-positive (stem cell marker) MNC subpopulations significantly improved endothelium-dependent vasodilation, although these treatments were not as effective as transfusion of total MNCs. Depletion of MNCs of either CD11b-positive, CD45R-positive, or Sca-1-positive cells resulted in significant attenuation of endothelium-dependent vasodilation as compared with nondepleted MNCs; however, vasoreactivity was still significantly improved as compared with saline-treated apoE-/- mice. Intravenous transfusion of spleen-derived MNCs improves endothelium-dependent vasodilation in atherosclerotic apoE-/- mice, indicating an important role of circulating progenitor cells for the repair of ongoing vascular injury. More than 1 subpopulation of the MNC fraction seems to be involved in this effect.

Animals↗

Increasing plasma potassium with amiloride shortens the QT interval and reduces ventricular extrasystoles but does not change endothelial function or heart rate variability in chronic heart failure.

OBJECTIVES: To test whether simply increasing plasma potassium with amiloride would exert any of the same beneficial effects on "surrogate outcome measures" that are seen with spironolactone. The latter has been shown to improve mortality in chronic heart failure, possibly as a result of improvements in endothelial dysfunction, vascular angiotensin converting enzyme (ACE), autonomic function, myocardial fibrosis, ventricular arrhythmias, and QT interval indices. DESIGN: Randomised, placebo controlled trial. SETTING: Teaching hospital. PATIENTS AND INTERVENTIONS: Double blind crossover study involving 10 patients with New York Heart Association functional class II-III chronic heart failure comparing 5 mg/day amiloride (one month) with placebo. MAIN OUTCOME MEASURES: Endothelial function, vascular ACE, collagen markers, 24 hour ECG, and QT interval results. RESULTS: The amiloride induced increase in serum potassium (0.4 mmol/l) did not significantly change endothelial dysfunction, vascular ACE, collagen markers, or heart rate variability. However, amiloride significantly improved QT interval indices, reducing both QT dispersion (from 65.7 ms to 50.9 ms, p = 0.001) and mean maximal corrected QT (from 445 ms to 435 ms, p = 0.008). Amiloride also reduced ventricular extrasystoles (p < 0.05). CONCLUSIONS: Amiloride shortens QT interval length and reduces ventricular extrasystoles in chronic heart failure, implying that this effect is caused by potassium retention per se. However, unlike spironolactone, amiloride did not improve endothelial dysfunction, vascular ACE, heart rate variability, or myocardial fibrosis, implying that spironolactone improves these latter effects by aldosterone blockade rather than by simply increasing serum potassium. Therefore, amiloride has fewer beneficial mechanistic effects than spironolactone, but it does share with spironolactone the ability to shorten the QT interval and reduce ventricular extrasystoles.

Aged↗

Is endothelial function impaired in erectile dysfunction patients?

Erectile dysfunction (ED) and vascular disease are thought to be linked at the level of the endothelium. Endothelial dysfunction, resulting in the inability of the smooth muscle cells lining the arterioles to relax, prevents vasodilatation. Likewise, penile erection depends on the relaxation of smooth muscle in the corpus cavernosum and the wall of small arteries. The aim was to assess the systemic vascular function in patients with ED. In all, 32 ED patients diagnosed with Doppler Ultrasound and the International Index of Erectile Function-5-item questionnaire and 25 healthy men as a control group enrolled to the study. They all underwent the tests including serum glucose and lipid levels. Echocardiography and exercise stress test was performed routinely. Baseline demographics (body mass index, heart rate and blood pressures), fasting glucose and lipid levels were not significantly different between ED and control groups. Endothelial-dependent brachial artery flow-mediated vasodilatation and brachial artery response to 0.4 mg nitroglycerine (NTG) were measured. Participants were negative on exercise stress test, and echocardiographic parameters including ejection fraction were similar. Endothelial-dependent brachial artery percent diameter change with flow-mediated dilatation (6.01+/-2.9 vs 12.3+/-3.5) and brachial artery response to NTG (12.8+/-4.2 vs 17.8+/-5.2) were significantly different between groups (P<0.001). We found that endothelial function was impaired in ED patients with no apparent cardiovascular disease and diabetes mellitus. This impaired function might be explained by the abnormality in systemic nitric oxide-cyclic guanosine monophosphate vasodilator system and suggest that ED and vascular disease may be linked at the level of the endothelium.

Endothelial Cells↗

Insulin-induced vasodilatation and endothelial function in obesity/insulin resistance. Effects of troglitazone.

Insulin resistance is associated with a decreased vasodilator response to insulin. Because insulin's vasodilator effect is nitric oxide dependent, this impairment may reflect endothelial dysfunction. Troglitazone, an insulin-sensitiser, might thus improve insulin-dependent and/or endothelium-dependent vascular function in insulin resistant obese subjects. For 8 weeks, fifteen obese subjects were treated with either 400 mg troglitazone once daily or placebo, in a randomised, double-blind, cross-over design. At the end of each treatment period, we measured forearm vasodilator responses (plethysmography) to intra-arterial administered acetylcholine and sodium nitroprusside; insulin sensitivity and insulin-induced vascular and neurohumoral responses (clamp); vasoconstrictor responses to NC-monomethyl-L-arginine (L-NMMA) during hyperinsulinaemia; and ambulatory 24-h blood pressure (ABPM). Baseline data (placebo) of obese subjects were compared with those obtained in lean control subjects. Obese subjects were insulin resistant compared with leans (whole-body glucose uptake: 26.8+/-3.0 vs. 53.9+/-4.3 [tmol kgl min-, p < 0.001). Troglitazone improved whole-body glucose uptake (to 31.9+/-3.3 micromol x kg(-1) x min(-1) , p=0.028), and forearm glucose uptake (from 1.09+/-0.54 to 2.31+/-0.69 micromol dL(-1) x min(-1), p=0.006). Insulin-induced vasodilatation was blunted in obese subjects (percent increase in forearm blood flow (FBF) in lean 66.5+/-23.0%, vs. 10.1+/-11.3% in obese, p=0.04), but did not improve during troglitazone. Vascular responses to acetylcholine, sodium nitroprusside and L-NMMA did not differ between the obese and lean group, nor between both treatment periods in the obese individuals. In conclusion, in insulin resistant obese subjects, endothelial vascular function is normal despite impaired vasodilator responses to insulin. Troglitazone improved insulin sensitivity but it had no effects on endothelium-dependent and -independent vascular responses. These data do not support an association between insulin resistance and endothelial function.

Acetylcholine↗

Zinc and endothelial function.

Zinc (Zn), an essential trace element, has antioxidant functions, stabilizes membranes, and plays a role in the activity of a host of Zn metalloenzymes. Zn deficiency has been shown to increase erythrocyte fragility, decrease the Zn content of the erythrocyte membrane, and alter erythrocyte membrane fluidity. Recent studies have shown that Zn deficiency induced by various mechanisms disrupts endothelial barrier cell function in vitro, and this was corrected with Zn supplementation. Moreover, physiological amounts of Zn attenuated the barrier dysfunction produced by the inflammatory cytokine tumor necrosis factor. These data have important implications for acute vascular processes, e.g., adult respiratory distress syndrome, and chronic vascular processes, e.g., atherosclerosis. The mechanisms by which Zn may affect endothelial cell function and attenuate cytokine-induced endothelial cell dysfunction are important areas of continuing investigation.

Arteriosclerosis↗

Effect of AT1 receptor blockade on hepatic redox status in SHR: possible relevance for endothelial function?

The study investigated whether the amelioration of endothelial dysfunction by candesartan (2 mg.kg-1.day-1; 10 wk) in spontaneously hypertensive rats (SHR) was associated with modification of hepatic redox system. Systolic arterial pressure (SAP) was higher (P < 0.05) in SHR than in Wistar-Kyoto rats (WKY) and was reduced (P < 0.05) by candesartan in both strains. Acetylcholine (ACh) relaxations were smaller (P < 0.05) and contractions induced by ACh + NG-nitro-l-arginine methyl ester (l-NAME) were greater (P < 0.05) in SHR than in WKY. Treatment with candesartan enhanced (P < 0.05) ACh relaxations in SHR and reduced (P < 0.05) ACh + l-NAME contractions in both strains. Expression of aortic endothelial nitric oxide synthase (eNOS) mRNA was similar in WKY and SHR, and candesartan increased (P < 0.05) it in both strains. Aortic mRNA expression of the subunit p22phox of NAD(P)H oxidase was higher (P < 0.05) in SHR than in WKY. Treatment with candesartan reduced (P < 0.05) p22phox expression only in SHR. Malonyl dialdehyde (MDA) levels were higher (P < 0.05), and the ratio reduced/oxidized glutathione (GSH/GSSG) as well as glutathione peroxidase activity (GPx) were lower (P < 0.05) in liver homogenates from SHR than from WKY. Candesartan reduced (P < 0.05) MDA and increased (P < 0.05) GSH/GSSG ratio without affecting GPx. Vessel, lumen, and media areas were bigger (P < 0.05) in SHR than in WKY. Candesartan treatment reduced (P < 0.05) media area in SHR without affecting vessel or lumen area. The results suggest that hypertension is not only associated with elevation of vascular superoxide anions but with alterations of the hepatic redox system, where ANG II is clearly involved. The results further support the key role of ANG II via AT1 receptors for the functional and structural vascular alterations produced by hypertension.

Angiotensin II↗

Endothelial function and the prediction of CVD in diabetes.

Endothelial dysfunction has received increasing attention as a potential contributor to the pathogenesis of vascular disease in diabetes mellitus. Technologies to detect endothelial dysfunction include assessment of endothelium-dependent vasodilatation and plasma levels of cell injury markers. Although clinical and epidemiologic studies show associations and potential links between endothelial dysfunction and outcome in diabetes, there is a substantial need for further work.

Atherosclerosis↗

Angiogenesis and endothelial cell function.

Endothelial cell growth is tightly regulated. During embryonic development endothelial cells rapidly proliferate thereby forming new blood vessels. Two different mechanisms contribute to the development of the vascular system: vasculogenesis, the development of blood vessels from in situ differentiating endothelial cells, and angiogenesis, the formation of capillaries from preexisting vessels. In the adult, endothelial cell turnover is very low but under a variety of pathological conditions such as tumor growth these cells quickly enter the cell cycle and divide. Vascular endothelial growth factor (VEGF) has been identified as a key regulatory paracrine growth factor for endothelial cells. Transient VEGF expression correlates with embryonic and tumor angiogenesis. On the other hand, constitutive expression of this factor in choroid plexus and kidney glomerular epithelium and its cognate receptors in adjacent fenestrated endothelium suggests a role for this ligand-receptor system in organotypic endothelial cell differentiation and capillary permeability of fenestrated endothelium.

Animals↗

Preservation of venous endothelial function in the forearm venous capacitance bed of patients with chronic heart failure despite arterial endothelial dysfunction.

OBJECTIVES: The goal of this study was to assess whether endothelial dysfunction occurs in the forearm venous capacitance bed of patients with chronic heart failure (CHF) and to determine the role of nitric oxide (NO) in modulating venous tone. BACKGROUND: Control of venous tone is crucially important in CHF. More than 70% of blood volume lies in the venous capacitance beds. Therefore, small changes in venous tone may markedly affect cardiac filling pressures and cardiac output. METHODS: Venous tone was measured using radionuclide forearm venous plethysmography in 24 patients with CHF and 16 age-matched controls. The effect of basal NO activity on venous tone was assessed by infusing N-monomethyl-L-arginine 12 mg/min and stimulated NO using carbachol 15 microg/min. Brachial artery flow-mediated dilation was assessed by ultrasonic wall-tracking. RESULTS: Blockade of basal NO release caused a significant and similar venoconstriction in patients (9.6 +/- 1.8%, p < 0.01) and controls (6.6 +/- 1.7%, p < 0.01). Carbachol-induced venodilation was significant and similar in patients (36.8 +/- 3.9%, p < 0.001) and controls (40.7 +/- 3.9%, p < 0.001). Brachial artery flow-mediated dilation was impaired in patients compared with controls (2.0 +/- 0.6% vs. 7.5 +/- 2.5%, p < 0.01). CONCLUSIONS: Our data indicate that, despite marked impairment of the function of the arterial endothelium, there is preservation of both basal and stimulated NO release in the forearm venous capacitance bed. This may provide important insights into mechanisms of endothelial dysfunction in CHF and the potential for novel therapy.

Aged↗

Corneal endothelial function and structure following cryo-injury in the rabbit.

Wide-field specular microscopy, fluorophotometry, pachymetry, and scanning electron microscopy are used to characterize a reproducible, in vivo model of corneal endothelial injury and recovery in the rabbit. Following an 8-mm central cryo-injury, the cornea remains thickened for as long as 3 weeks. Mean endothelial permeability to fluorescein is above normal for 10 days following injury, but by 14 days postinjury the endothelial permeability to fluorescein is not statistically significantly different from preinjury control values, thus indicating that endothelial permeability probably returns to normal by approximately 2 weeks postinjury. Cell morphology, as determined by scanning electron microscopy, is also essentially normal by 2 weeks postinjury. Endothelial permeability appears to recover before stromal thickness normalizes, suggesting a lag in recovery of endothelial pump function.

Animals↗

Postprandial triglycerides and endothelial function.

Several studies support the association between postprandially elevated triglyceride levels and atherosclerosis. Histological and cell culture investigations revealed, that triglyceride rich postprandial lipoproteins are taken up by macrophages and smooth muscle cells and are detectable as part of foam cells in vascular lesions. Remnant particles, generated by lipolysis of postprandial lipoproteins in vitro and fatty acids increase the permeability of the endothelium and are cytotoxic for endothelial cells. Besides these morphological changes of cells, lipoproteins have been shown to exert effects on cellular functions like the expression of membrane proteins and the production or release of several bioactive substances regulating communication with blood cells and other cell systems of the vascular wall, blood pressure and hemostasis. This review concentrates on the influence of postprandial lipoproteins on factors involved in the interaction of endothelial cells with blood leukocytes and factors mediating blood pressure regulation. Increased expression of adhesion molecules has been detected immunehistochemically in atherosclerotic plaques in animals and humans. It was demonstrated that patients with elevated triglyceride levels have increased levels of soluble adhesion molecules. Furthermore, postprandial lipoproteins were shown to induce membrane expression of adhesion molecules. This effect seems to be at least in part mediated by the oxidative modification of the particles. Accordingly chylomicrons separated after ingestion of safflower oil, rich in polyunsaturated linoleic acid, induced higher adhesion molecule expression at higher oxidant concentration compared with chylomicrons separated after ingestion of olive oil, rich in monounsaturated oleic acid. Several authors described effects of fatty acids on the expression of adhesion molecules. On the one hand, they may exert stimulatory effects as such, on the other hand cytokine induced adhesion molecule expression may be enhanced by certain fatty acids and inhibited by others, implying an interference with signal transduction processes. Effects of lipoproteins on vasoactive substances seem to be implicated in endothelial dysfunction, too. The endothelium-derived relaxing factor nitric oxide (NO) has gained increasingly attention in the last two decades and is regarded as protective against hypertension and atherosclerosis. It was demonstrated that chylomicrons and their remnants inhibited endothelium-dependent relaxations in isolated aortas. Vasodilatatory responses and nitric oxide metabolism were shown to be affected by the amount and composition of dietary fat. Cell culture experiments revealed modulation of NO release by certain fatty acids. Plasma levels of endothelin-1, a strong vasoconstrictor, have been shown to be increased in patients with type 2 diabetes and metabolic syndrome, respectively. Postprandially elevated triglycerides increased endothelin-levels in addition to insulin in patients with metabolic syndrome. In summary, there is evidence that the association between postprandial triglycerides and the metabolic syndrome is driven by direct influences on endothelial functions because plasma triglyceride levels are associated with levels of humoral risk markers of endothelial origin, and postprandial lipoproteins stimulate the release and/or expression of endothelial mediators in vitro, which induce atherogenesis and hypertension.

Animals↗

[Effect of Zhenju Jiangya Tablet on the endothelial function of hyperlipidemic rabbits].

OBJECTIVE: To study the effect of Zhenju Jiangya Tablet (ZJ) on the injured endothelial cells and endothelium-dependent relaxation function of hyperlipidemia rabbits. METHODS: Male New Zealand rabbits were randomized into four groups: control group, hyperlipidemia group, ZJ group and sivastatin group. The endothelium-dependent relaxation function was evaluated by APV using intravascular Doppler, and the morphology of endothelial cells was detected by light microscopy and electron microscopy, and nitric oxide synthase was evaluated. RESULTS: ZJ reduced the lesions of hyperlipidemia vessels, and the APV after Ach injection of each group was (1.14+/-0.26), (1.74+/-0.59), (1.22+/-0.37) and (1.17+/-0.41) respectively. The eNOS of each group was (4.21+/-0.37), (1.43+/-0.88), (3.95+/-0.67) and (4.08+/-0.46) nmol x min(-1) x g(-1) respectively. CONCLUSION: ZJ can improve the abnormality of endothelial cells and endothelium-dependent relaxation function of hyperlipidemia.

Animals↗

High-dose atorvastatin therapy is required for significant improvement of endothelial function in heterozygous familial hypercholesterolaemic patients.

This study evaluated endothelial dysfunction (ED) by measuring flow-mediated vasodilation (FMD) and for six months documented changes in ED, LDL-C levels and serum concentrations of inflammatory markers with high- and low-dose atorvastatin therapy. In 23 heterozygous familial hypercholesterolaemic (FH) patients, FMD, LDL-C and inflammatory markers (sVCAM-1, sICAM-1, E-selectin and highly sensitive C-reactive protein) were measured at baseline (untreated) and on atorvastatin 20 and 80 mg/day. In untreated patients, FMD was significantly reduced (mean +/- SD = 3.09 +/- 0.91%) compared with 10 normocholesterolaemic controls (8.71 +/- 2.41%; p < 0.01). FMD improved non-significantly with atorvastatin 20 mg/day (5.60 +/- 1.17%), but showed a significant improvement (8.54 +/- 1.11%; p < 0.01) with atorvastatin 80 mg/day. LDL-C decreased markedly (-42.4%; p < 0.0001) on 20 mg/day and decreased further (-48.6%; p < 0.05) on 80 mg/day. FMD improvement, however, did not correlate with LDL-C reduction. No significant changes occurred in any inflammatory markers. We concluded that ED was present in untreated FH patients and improved significantly on high-dose atorvastatin. There was no correlation between the changes in FMD and LDL-C, suggesting either a LDLC-independent effect on ED, or that a marked reduction in LDL-C is required to normalise ED in FH.

Adult↗

Vitamin E supplementation improves endothelial function in type I diabetes mellitus: a randomized, placebo-controlled study.

OBJECTIVES: We sought to determine, in a double-blind, placebo-controlled, randomized study, whether vitamin E supplementation (1,000 IU for three months) would improve impaired conduit and resistance vessel endothelial vasodilator function (EVF) and systemic arterial compliance (SAC) in type I diabetes mellitus (DM). BACKGROUND: Oxidative stress is thought to be important in the pathogenesis of impaired EVF. Consistent with this hypothesis, we have recently shown that impaired EVF is related to low density lipoprotein (LDL) vitamin E content (VEC) in young subjects with type 1 DM. METHODS: We assessed EVF in the brachial artery (using noninvasive ultrasound, flow-mediated vasodilation [FMD]; n = 41) and in the forearm resistance vessels (by flow responses to intrabrachial acetylcholine [ACh]; n = 21) and measured SAC (simultaneous aortic blood flow and carotid pressure measurements; n = 41) before and after active or placebo therapy. RESULTS: The LDL VEC was increased by 127% after supplementation, resulting in a significant reduction in the oxidative susceptibility of LDL. There was no time-dependent change in FMD or in the response to ACh or SAC in the placebo group. A significant improvement in FMD (2.6 +/- 0.6% to 7.0 +/- 0.7%, p < 0.005) and the dose response to ACh (p < 0.05) were observed in those randomized to vitamin E therapy. Systemic arterial compliance was not affected by vitamin E (0.41 +/- 0.03 vs. 0.49 +/- 0.06 arbitrary compliance units, p = NS). The change in FMD was related to the change in LDL VEC (r = 0.42, p < 0.05) and the change in the oxidative susceptibility of LDL (r = 0.64, p < 0.0001). CONCLUSIONS: Short-term daily oral supplementation with vitamin E improves EVF in both the conduit and resistance vessels of young subjects with type I DM.

Administration, Oral↗