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PubMed2002

Endothelial function in pigs transgenic for human complement regulating factor.

BACKGROUND: Expression of human complement regulating factor (hCRF) in porcine organs prevents hyperacute rejection of these organs after xenotransplantation to nonhuman primates. Experiments were designed to characterize endothelial and smooth muscle function of arteries from pigs transgenic for hCD46. METHODS: Arterial blood from outbred pigs transgenic for hCD46 expression and nontransgenic animals of the same lineage was analyzed for angiotensin-converting enzyme (ACE), C-type natriuretic peptide (CNP), and nitric oxide. Aortic endothelial cells were prepared for measurement of mRNA or activity for nitric oxide synthase (NOS). Rings cut from femoral and pulmonary arteries were suspended in organ chambers for measurement of isometric tension. RESULTS: CNP was significantly greater, ACE was similar, and nitric oxide was significantly less in plasma from transgenic compared with nontransgenic pigs. Neither mRNA nor activity of NOS differed between the groups. Endothelium-dependent relaxations to bradykinin and acetylcholine but not the calcium ionophore were shifted significantly to the left in femoral and pulmonary arteries from hCD46 transgenic pigs compared with nontransgenic pigs. The ACE-inhibitor captopril augmented relaxations similarly in both groups, but NG-monomethyl-L-arginine (L-NMMA) did not inhibit relaxations in rings from transgenic pigs. CONCLUSIONS: Data suggest that expression of hCD46 on endothelium of pigs selectively augments endothelium-dependent relaxations to bradykinin by increased release of endothelium-derived factors other than nitric oxide. There does not seem to be any change in activity of ACE or NOS with expression of the human protein. Increased relaxations to bradykinin may be beneficial in lowering vascular resistance when transgenic organs are used for xenotransplantation.

Angiotensin I↗

PubMed2002

Maintenance of a functional endothelial cell monolayer on a fibroblast/polymer substrate under physiologically relevant shear stress conditions.

The suitability of using a fibroblast-seeded polymer scaffold as a substrate for forming an endothelial monolayer which is responsive to flow has been investigated. The results indicate that a confluent monolayer of endothelial cells can be formed on the top surface of the fibroblast/polymer substrate. This monolayer has an elongated, oriented morphology and alignment even in static culture, and the application of shear stress perpendicular to the endothelium's static alignment causes a progressive reorganization of the cytoskeletal component, F-actin, with a corresponding change in endothelial cell shape from elongated in the direction of flow, to a more "cobble-stone" morphology, to finally elongation in the direction of flow. The production of nitric oxide by this co-culture increases not only in a time and shear stress dependent fashion, but also as a function of the direction of flow in relation to the static alignment of the endothelium. The data obtained also indicate that the coculture had higher levels of ICAM-1 production and monocyte adhesion than seen in ECs on tissue culture plastic, which may be a function of the endothelial cells being in direct contact with the fibroblast cell line. These results demonstrate that a fibroblast/polymer scaffold can serve as a suitable substrate for ECs and that such a monolayer demonstrates the normal EC responsiveness to flow.

Actins↗

PubMed2002

Microbubble-endothelial cell interactions as a basis for assessing endothelial function.

Clinical signs and symptoms of coronary artery disease are predated in decades by endothelial dysfunction, an aberration in the vascular lining that permits the development and propagation of atherosclerotic lesions and vasomotor dysfunction in the arterial circulation. These ultimately lead to acute and chronic coronary ischemic syndromes. Other pathophysiologic scenarios encountered in clinical cardiology practice, such as cardiac transplant rejection and the period following coronary angioplasty or cardiac surgery, also are associated with endothelial dysfunction. Endothelial dysfunction parallels coronary risk factors and is potentially reversible, rendering early identification of the phenomenon a clinically important endpoint. Current methods for detecting endothelial dysfunction are limited, however. Myocardial contrast echocardiography using microbubbles targeted to bind to cell surface markers uniquely expressed by dysfunctional endothelial cells may offer an approach to the noninvasive detection of endothelial disease using clinical ultrasound imaging techniques. This article will discuss the concept of targeted ultrasound imaging and present preliminary studies in this area as applied to endothelial assessment. Potential applications to other disease states, both diagnostic and therapeutic, also are discussed.

Contrast Media↗

PubMed2006

A randomized, double-blind trial comparing the effects of amlodipine besylate/benazepril HCl vs amlodipine on endothelial function and blood pressure.

Evidence suggests that renin-angiotensin-aldosterone system inhibition ameliorates endothelial dysfunction. The authors examined the effect of amlodipine besylate/benazepril HCl combination treatment compared with amlodipine besylate monotherapy in modulating endothelial dysfunction. This multicenter, double-blind, 12-week study randomized 70 hypertensive subjects with at least one other endothelial dysfunction risk factor to amlodipine besylate/benazepril HCl (5/20 mg/d force-titrated to 5/40 mg/d) or amlodipine besylate monotherapy (5 mg/d force-titrated to 10 mg/d). Both the combination and monotherapy produced significant median increases from baseline in percentage flow-mediated vasodilation (2.0% and 1.2%, respectively) and percentage change in percent flow-mediated vasodilation (25% and 16%, respectively). These improvements were numerically larger with combination treatment, but between-group differences did not achieve statistical significance. Reductions in systolic and diastolic blood pressure were significantly greater (P=.0452/P=.0297) with combination treatment (-18.6/-12.3 mm Hg) than with monotherapy (-14.8/-9.1 mm Hg). A highly positive correlation between change in systolic blood pressure and change in percent of flow-mediated vasodilation was demonstrated only for combination treatment.

Aged↗

PubMed2006

Effect of radiofrequency catheter ablation on endothelial function and oxidative stress.

OBJECTIVE: Thromboembolic complications commonly occur in radiofrequency (RF) ablation procedures. Endothelial injury is believed to be induced during the process of RF ablation and to be involved in the mechanisms of thromboembolism. In this study, we gave further information about endothelial injury and also investiged the possible reasons for endothelial dysfunction during RF. METHODS AND RESULTS: Plasma levels of nitric oxide (NO), a biomarker of endothelial injury and some antioxidants and oxidants: beta-carotene (beta-CAR), lipoperoxide (LPO), superoxide dismutase (SOD), vitamin C (VC) and vitamin E (VE) were measured in 44 patients who underwent radiofrequency catheter ablation. Plasma NO concentration decreased significantly from 433.27 +/- 59.93 nmol/L to 407.13 +/- 52.32 nmol/L during RF ablation. Levels of beta-CAR, LPO, SOD,VC and VE were not significantly different. The decrease of plasma NO level was significantly correlated with ablation duration and cumulative ablation energy but had no significant correlation with overall procedure time, output ablation energy, ablation temperature and age of the patients. CONCLUSIONS: Radiofrequency catheter ablation induced endothelial injury but had no effect on oxidative stress. Radiofrequency energy was the main factor that caused endothelial injury during RF ablation.

Adult↗

PubMed2026

Targeted Nrf2 activation improves vascular endothelial function with aging and prevents vascular dysfunction following disuse in younger and older adults.

Aging and physical inactivity/disuse contribute to cardiovascular disease, which is attributable, in part, to vascular endothelial dysfunction associated with impaired nuclear-factor erythroid 2-related factor 2 (Nrf2) signaling. However, the ability to augment Nrf2 activation and its effects on age- and disuse-related vascular dysfunction in humans remains limited. In a double-blind, randomized, placebo-controlled study design 20 younger adults (8M/12F, age 27 ± 7 y) and 24 older adults (12M/12F, age 67 ± 8 y) were randomized to receive either placebo or PB125 (200 mg/day, Nrf2 activator) across three visits: baseline, 2 weeks of supplementation, and following either 5 days of bed rest (old) or 2 weeks of limb immobilization (young). Brachial and popliteal artery flow-mediated dilation (FMD), passive leg movement-induced (PLM) leg blood flow (LBF) and vascular conductance (LVC) and serum antioxidant status (superoxide dismutase, SOD) were assessed at each timepoint. Compared to placebo, 2 weeks of PB125 increased brachial (PB125: 2.8 ± 1.5 to 3.8 ± 1.3%, p < 0.0001) and popliteal FMD (PB125: 1.5 ± 1.5 to 2.3 ± 1.4%, p = 0.033) in older, but not younger adults (both, p > 0.27). During bed rest, PB125 preserved brachial (3.8 ± 1.3 to 3.6 ± 1.4%, p = 0.543) and popliteal FMD (2.3 ± 1.4 to 2.7 ± 1.4%, p = 0.269), LVC (1.1 ± 0.8 to 1.1 ± 1.5 AUC, p = 0.530) and circulating SOD concentrations (28.3 ± 7.2 to 28.6 ± 8.6 U/mL, p = 0.888) in older adults compared to placebo (all, p < 0.05). Following limb immobilization, PB125 preserved popliteal FMD (4.4 ± 2.8 to 3.4 ± 1.8%, p = 0.302) in younger adults compared to placebo (p < 0.05). These findings demonstrate targeted Nrf2 activation with PB125 improves age-related vascular endothelial dysfunction while preserving vascular function and antioxidant capacity following periods of disuse.

Humans↗

PubMedDate not supplied

[Hemostatic system factors and endothelial function in primary pulmonary hypertension].

Primary pulmonary hypertension (PPH) is a rare disorder, usually fatal. Although the cause of the disease is unknown, the vascular endothelium seems to play a key role. It has been proposed that a vascular endothelial dysfunction would provoke pulmonary vasoconstriction, platelet activation and thrombin formation; some of these events have already been proven. The presence of thrombosis in PPH patients has been demonstrated, and it seems to have a relationship with a vascular endothelium-dependent coagulation abnormality. Substances of endothelial cell origin capable of modifying the coagulation mechanisms are: heparan-sulfate, thrombomodulin, protein S, tissue factor pathway inhibitor (TFPI), tissue factor, von Willebrand factor, prostacyclin and endothelial-derived relaxing factor; functional and multimeric-pattern alterations in von Willebrand factor have already been reported in PPH patients.

Endothelium, Vascular↗

PubMed1996

Chronic inhaled nitric oxide: effects on pulmonary vascular endothelial function and pathology in rats.

Nitric oxide (NO) is a potent endogenous vasodilator produced in endothelial cells. Inhaled NO selectively vasodilates the pulmonary circulation. We determined the effects of chronic inhaled NO on hypoxic pulmonary vascular remodeling and endothelium NO-dependent and -independent vasodilation during normoxic and hypoxic conditions in rats. Rats were exposed to 3 wk of normoxia (N), normoxia + 20 ppm inhaled NO (N+NO), chronic hypoxia with 10% normobaric oxygen (CH), or CH and 20 ppm inhaled NO (CH+NO). Inhaled NO decreased the number of muscular pulmonary arteries, the medial smooth muscle thickness, and the right ventricular hypertrophy associated with chronic hypoxia but had no effect on these parameters in normoxic rats. All groups were evaluated with isolated perfused lungs. The pulmonary artery pressure increased by the same amount in the CH and CH+NO rats compared with N rats. Inhibition of NO synthase with N omega-nitro-L-arginine methyl ester (L-NAME) caused greater pulmonary vasoconstriction in CH (19.2 +/- 3.7 mmHg) vs. N (7.8 +/- 3.0 mmHg) and less in CH+NO (9.1 +/- 0.8 mmHg) vs. CH rats. Bradykinin (3 micrograms) caused greater vasodilation in CH (76 +/- 12%) vs. N (29 +/- 5%) but significantly less in CH+NO (41 +/- 11%) vs. CH rats. Vasodilation with acute inhaled NO (40 ppm) was no different in CH vs. N rats but was lower in CH+NO (19 +/- 5%) vs. CH (34 +/- 6%) rats. This study demonstrates that chronic inhaled NO attenuates hypoxic pulmonary vascular remodeling. Furthermore, these results suggest that chronic inhaled NO decreases endothelium NO-dependent and -independent vasodilation.

Administration, Inhalation↗

PubMed2002

Small amounts of venous gas embolism cause delayed impairment of endothelial function and increase polymorphonuclear neutrophil infiltration.

Gas bubbles from decompression and gas embolization lead to endothelial dysfunction and mechanical injury in the pig, rabbit and lamb. In the study presented here, 0.01 ml air/min/kg was infused through a catheter into the jugular vein in 12 rabbits for 60 min. The endothelial response was measured using tension measurements in the blood vessel wall, and morphological changes where quantified using light microscopy and image processing. Percent lung water content was calculated and used to estimate the severity of pulmonary oedema. The infusion led to a significant decrease in the acetylcholine-mediated endothelial-dependent vasodilatation in the pulmonary artery 6 h after the infusion (6-h group, n = 6). A decrease in substance-P-mediated endothelial-dependent vasodilatation was also detected. No changes where seen in a group of rabbits examined 1 h after infusion (l-h group, n=6). The impaired endothelial-dependent vasodilatation caused by the bubbles is probably biochemical in origin, since no visible changes were seen in the endothelial layer. A significant increase in polymorphonuclear neutrophils was observed in the 6-h group compared to the l-h group. This study demonstrates that small numbers of bubbles, corresponding to "silent bubbles", lead to an impairment of the endothelial-dependent vasoactive response.

Acetylcholine↗

PubMed2006

Antioxidant vitamin C improves endothelial function in obstructive sleep apnea.

RATIONALE: Obstructive sleep apnea (OSA) is associated with oxidative stress, endothelial dysfunction, and increased cardiovascular morbidity and mortality. OBJECTIVE: We tested the hypothesis that endothelial dysfunction in patients with OSA is linked to oxidative stress. METHODS: In the present study, we measured flow-mediated dilation (FMD) of the brachial artery by ultrasound in 10 otherwise healthy, untreated patients with OSA and 10 age-and sex-matched control subjects without sleep-disordered breathing before and after intravenous injection of the antioxidant vitamin C. The investigator performing the FMD measurements was blinded to the status of the patients. RESULTS: When compared with control subjects, baseline FMD was significantly reduced in the patients with OSA. After intravenous injection of 0.5 g vitamin C, vasoreactivity remained unchanged in the control subjects. In the patients with OSA, ascorbate led to an increase in FMD to a level comparable to that observed in the control group. CONCLUSION: The reduced endothelial-dependent vasodilation in untreated patients with OSA acutely improves by the free radical scavenger vitamin C. These results are in favor of oxidative stress being responsible for the endothelial dysfunction in OSA. Antioxidant strategies should be explored for the treatment of OSA-related cardiovascular disease.

Administration, Sublingual↗

PubMed1994

Cultured endothelial cells restore vasodilator responses to coronary arteries with impaired endothelial function and alter the response to a nitric oxide donor.

The objective of this investigation was to determine the effect of cultured human umbilical vein endothelial cells (HUVEC) on the vascular response to canine coronary arteries in which the endothelium had been either mechanically removed or injured by multiple brief episodes of occlusion and reperfusion in vivo. The endothelium-dependent vasodilator, A23187 (10(-6) mol/l) did not cause any significant relaxation in vessels from which the endothelium had been removed. However, following addition of cultured HUVEC to the tissue bath (75 x 10(3) cells/ml), A23187 produced a significant (p < 0.05) relaxation. This effect was abolished by inhibition of nitric oxide synthase with Nw-nitro-l-arginine methyl ester (L-NAME). Vascular relaxation caused by the nitric oxide donor SIN-1 was significantly (p < 0.05) enhanced when cultured HUVEC were added to vessels mechanically denuded of endothelium. Repetitive ischemia and reperfusion significantly inhibited the relaxant response to A23187. Addition of cultured HUVEC to the tissue bath partially restored the response to A23187. In contrast to the mechanically damaged vessels the relaxant response to SIN-1 was unaffected by cultured HUVEC in reperfusion-injured vessels. These results demonstrate that cultured endothelial cells partially restore endothelium-dependent vasodilation of vessels in which the endothelium is not functional following mechanical- or reperfusion-induced damage. The differential effect of endothelial cells on the response to SIN-1 suggests that mechanical and reperfusion injury alter the coronary vascular response to SIN-1 by different mechanisms.

Animals↗

PubMed2004

17beta-estradiol preserves endothelial function by reduction of the endogenous nitric oxide synthase inhibitor level.

Previous studies have shown that endothelial dysfunction is associated to an increase of endogenous nitric oxide synthase (NOS) inhibitor level and estrogen reduces impairment of the endothelium due to oxidized low-density lipoprotein (LDL). The purpose of the present study was to investigate the effect of estradiol on endothelial dysfunction and the increased level of asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, induced by LDL. Male Sprague-Dawley rats were treated with a single injection of native LDL (4 mg/kg) for 48 h. Vasodilator responses to acetylcholine in the aortic rings and serum levels of ADMA and malondialdehyde (MDA) were determined. Treatment with native LDL markedly reduced endothelium-dependent relaxation to acetylcholine in the isolated rat thoracic aortic rings and increased serum levels of ADMA and MDA (P < 0.01). Pretreatment with 17beta-estradiol (0.1 or 0.3 mg/kg) significantly attenuated inhibition of vasodilator responses to acetylcholine and elevation of both ADMA and MDA concentration by LDL (P < 0.01). These results suggest that estradiol possesses a protective effect on the endothelium and the protective effect is related to reduction of ADMA concentration by inhibition of lipid peroxidation.

Analysis of Variance↗

PubMed1999

Improvement of endocardial and vascular endothelial function on myocardial performance by captopril treatment in postinfarct rat hearts.

Background-Endocardial (EE) and myocardial capillary vascular endothelial (myocap VE) cells have been shown to modulate the contractile characteristics of myocardium in a calcium-dependent manner. We evaluated the endothelial-myocardial interaction in the rat postinfarction myocardial infarction (MI) model and the effects of captopril. Methods and Results-Wistar rats were divided into 4 groups treated for 4 weeks: (1) control; (2) infarcted controls (left anterior coronary artery ligation); (3) infarcted+captopril 2 g/L in drinking water; and (4) infarct+captopril+triton intracoronary injection. Coronary VE function was evaluated by infusion of serotonin in Langendorff preparations (n=31), and the myocardial contractile characteristics were investigated by use of isolated papillary muscles (n=44). Cardiac mRNA for endothelial constitutive nitric oxide synthase (ecNOS) was measured, and its cellular location was evaluated by immunohistochemistry. Serotonin-induced increase in coronary flow was decreased in infarct controls compared with controls (4.6% versus 53.4%, P<0.01) but not in the 2 infarct+captopril groups. Intracoronary triton injection decreased serotonin-induced coronary flow in the infarct+captopril+triton group. All MI groups had decreased total tension in isolated papillary muscles. EE removal by triton immersion decreased total tension in all groups except for infarct controls (3.3 versus 3.2 g/mm(2)). Cardiac ecNOS mRNA decreased in the control infarct group but remained normal in the infarct+captopril group. Conclusions-Chronic postinfarction endothelium-induced coronary vasodilatation is impaired, and both EE and myocap VE dysfunction contribute to myocardial depression. Captopril use prevents these abnormalities and the reduction of cardiac ecNOS mRNA.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1983

Purification of human platelet calcium-activated protease. Effect on platelet and endothelial function.

Calcium-activated protease (CAP) was purified from the cytosol fraction of homogenized human platelet concentrates using a combination of gel filtration chromatography and affinity chromatography on antipain aminohexyl-Sepharose and activated thiol-Sepharose 4B. Purified CAP is composed of two different polypeptides of Mr = 80,000 and 27,000. Half-maximal protease activity was observed at 0.52 mM Ca2+, and all activity was inhibited by antipain, leupeptin, and N-ethylmaleimide. Activated CAP showed a time-dependent inactivation in the presence of 1 mM Ca2+ with only 5% of the control protease activity remaining after a 1-h exposure to calcium. Preincubation of washed platelets with varying amounts of CAP (0.2-0.4 units) significantly interfered with thrombin-induced platelet aggregation. In addition, ristocetin-induced platelet agglutination in the presence of von Willebrand factor was completely inhibited by 0.4 units of CAP. Concomitant with these protease-induced changes in platelet function, a decrease was observed in a major glycoprotein band of Mr = 150,000 present in platelet membranes and presumed to be glycoprotein Ib. In addition to these effects on platelets, CAP inhibited thrombin-induced production of prostacyclin by cultured human endothelial cells in a dose-dependent manner when the cells were pretreated with CAP. Thus platelet CAP can modulate membrane functions in both platelets and endothelial cells and may thus contribute to the regulation of hemostasis.

Blood Platelets↗

PubMed2000

Influence of enalapril on the endothelial function of DOCA-salt hypertensive rats.

In the present study, we investigated whether the correction of endothelial dysfunction can be independent of the normalization of high blood pressure levels by enalapril in deoxycorticosterone (DOCA-salt) hypertensive rats. Aorta morphology and the response of aortas with (E+) and without (E-) endothelium to noradrenaline, acetylcholine, and sodium nitroprusside were studied. DOCA-salt hypertensive and normotensive (control) rats were or were not treated with enalapril (5 mg/day/rat in the drinking fluid) for 1, 7, or 15 days. Blood pressure was measured before and after 1, 3, 7, and 15 days of enalapril treatment. Enalapril normalized the high blood pressure levels in 50% (responders) of the hypertensive rats after 3 to as many as 15 days but not after 1 day of treatment. Initial blood pressure levels were not different between responders and nonresponders. Blood pressure levels of normotensive control rats were not altered by enalapril treatment. The tunica media of aortas of DOCA-salt hypertensive rats treated or not treated with enalapril for 15 days was thicker than aortas from normotensive rats. Enalapril corrected the reduced response to acetylcholine observed in aorta from hypertensive rats from the first day of treatment. This treatment rendered aortas from normotensive control rats more sensitive (lower EC(50)) to acetylcholine without a change in the maximal responses. The responses to sodium nitroprusside, a nitric oxide donor, were unaltered in aorta E+ or E- from control and hypertensive rats before and after enalapril treatment. Enalapril did not correct the increased responses to noradrenaline observed in aorta E+ of hypertensive rats. These results suggest that the high blood pressure in DOCA-salt hypertension is not correlated with the altered response to endothelium-dependent agents (either dilator or constrictors). The endothelium-dependent vasodilation by antihypertensive agents can be corrected independently of normalization of blood pressure levels or the vascular morphology.

Acetylcholine↗

PubMed2005

Metformin administration improves endothelial function in women with polycystic ovary syndrome.

OBJECTIVE: The aim of this study was to investigate the endothelial status in young women with polycystic ovary syndrome (PCOS), using a simple and easily reproducible hemodynamic method combined with a biological marker and to evaluate the effect of metformin treatment on these parameters. DESIGN: Descriptive clinical trial. METHODS: Forty young women, 20 with PCOS and 20 normal women of similar age and body mass index were studied. Metformin (1700 mg daily) was administered for 6 months to the PCOS group. The endothelium status and the metabolic and hormonal profile were studied in both groups, as well as after metformin, by flow-mediated dilatation (FMD) on the brachial artery and by measurements of plasma endothelin-1 (ET-1) levels. RESULTS: FMD was impaired in the PCOS group when compared with controls (3.24+/-0.71% vs 8.81+/-1.07% respectively, P<0.0001), but this difference normalized after metformin treatment (PCOS(post-metformin) vs controls: 8.17+/-1.26 vs 8.81+/-1.07%, P = 0.70) since the values significantly improved after metformin treatment (PCOS(pre-metformin) vs PCOS(post-metformin): 3.24+/-0.71 vs 8.17+/-1.26%, P=0.003). ET-1 levels were significantly higher in the PCOS women compared with the control group (7.23+/-0.50 vs 4.99+/-0.69 fmol/l, P=0.01), they improved significantly after metformin treatment (PCOS(pre-metformin) vs PCOS(post-metformin): 7.23+/-0.50 vs 3.57+/-0.60 fmol/l, P<0.0001) and their difference compared with the control group was reversed (PCOS(post-metformin) vs controls: 3.57+/-0.60 vs 4.99+/-0.69 fmol/l, P=0.13). Metformin administration improved hyperandrogenemia. However, in this study, mathematical methods used to assess insulin resistance failed to show any detected alteration after treatment with metformin. CONCLUSIONS: PCOS women were found to exhibit endothelial dysfunction compared with controls, which was reversed 6 months after metformin administration.

Adult↗

PubMed2003

[Endothelial function].

It is well known that diabetes mellitus often combines with hypertension. Diabetes mellitus is associated with endothelial dysfunction. An imbalance of reduced production of nitric oxide or increased production of reactive oxygen species, mainly superoxide, may promote endothelial dysfunction. One mechanism by which endothelium-dependent vasodilation is impaired is an increase in the oxidative stress that inactivates nitric oxide. Both high glucose and insulin resistance reduce the bioavailability of nitric oxide through an increase in oxidative stress. It is unclear that endothelial dysfunction is a cause or consequence of hypertension. In this review, we present the possibility that endothelial dysfunction causes hypertension in diabetes mellitus.

Arteriosclerosis↗

PubMed1998

[The beneficial effect of natural antioxidants on the endothelial function of regenerated endothelium].

HYPOTHESIS: Lipid peroxidation and LDL oxidation have been implicated in intimal hyperplasia and endothelial dysfunction following direct arterial trauma. OBJECTIVES: The aim of this study was to evaluate the effects of megadose of natural antioxidant vitamin E (VE) combined to vitamin C (VC) on the regenerated endothelial dysfunction. METHOD: A first group of rats (VE and C) (n = 10) was pretreated with VE (500 IU/kg/day) and VC (1200 mg/kg/day) for 4 weeks before aortic (thoracic) endothelial denudation with a Fogarty catheter. Rats were then fed with the same vitamin supplemented diet for 2 months. A second group (n = 10) was similarly denuded and treated with soya oil (SO), VE vehicle, for the same period; a third group (n = 10) was denuded only (DN); and a fourth group was maintained on a regular diet (CL) without denudation. Endothelial-dependent and independent relaxation was assessed in organ chambers. RESULTS: Vascular relaxation to nitric oxide analogue sodium nitroprusside was not affected either by the regenerative process or the vitamin supplementation. However, endothelial-dependent relaxation to acetylcholine, was significantly preserved in VE and C (p < 0.01) treated animals compared to DN group. CONCLUSION: These results suggest that, in this model, dietary megadose of antioxidants vitamin initiated 4 weeks before denudation can improve the post-regenerative endothelial dysfunction and could contribute to the prevention of the atherosclerotic process.

Acetylcholine↗