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PubMed2004

Acetylcysteine reduces plasma homocysteine concentration and improves pulse pressure and endothelial function in patients with end-stage renal failure.

BACKGROUND: Increased oxidative stress, elevated plasma homocysteine concentration, increased pulse pressure, and impaired endothelial function constitute risk factors for increased mortality in patients with end-stage renal failure. METHODS AND RESULTS: We investigated the metabolic and hemodynamic effects of intravenous administration of acetylcysteine, a thiol-containing antioxidant, during a hemodialysis session in a prospective, randomized, placebo-controlled crossover study in 20 patients with end-stage renal failure. Under control conditions, a hemodialysis session reduced plasma homocysteine concentration to 58+/-22% predialysis (mean+/-SD), whereas in the presence of acetylcysteine, the plasma homocysteine concentration was significantly more reduced to 12+/-7% predialysis (P<0.01). The reduction of plasma homocysteine concentration was significantly correlated with a reduction of pulse pressure. A 10% decrease in plasma homocysteine concentration was associated with a decrease of pulse pressure by 2.5 mm Hg. Analysis of the second derivative of photoplethysmogram waveform showed changes of arterial wave reflectance during hemodialysis in the presence of acetylcysteine, indicating improved endothelial function. CONCLUSIONS: Acetylcysteine-dependent increase of homocysteine removal during a hemodialysis session improves plasma homocysteine concentration, pulse pressure, and endothelial function in patients with end-stage renal failure.

Acetylcysteine↗

PubMed1997

Radial artery has higher receptor-mediated contractility but similar endothelial function compared with mammary artery.

BACKGROUND: The radial artery (RA) has been used as an alternative arterial graft for coronary artery bypass grafting, but this artery has been suggested to be spastic. Endothelin-1 (ET) and angiotensin II (AII) have been measured with increased plasma concentrations during cardiopulmonary bypass. However, whether RA is reactive to these two important receptor-mediated vasoconstrictors is unknown. Also unknown is the endothelial function of this arterial conduit. This study was designed to compare RA and the internal mammary artery regarding the contractile characteristics to ET-1 and AII and endothelial function. METHODS: Ring segments of the RA and internal mammary artery taken from patients undergoing coronary artery bypass grafting were studied in organ chambers at a physiologic pressure. The contractility was determined from the contraction induced by ET-1 and AII as contraction force and the force normalized by circumference (g/mm). The endothelium-dependent relaxation was induced by the calcium ionophore A23187, a nonreceptor agonist, and substance P, a receptor agonist for endothelium-derived relaxing factors. Nitroglycerin was used to study the endothelium-independent relaxation. RESULTS: Both ET-1 and AII induced a higher contraction force (9.0 +/- 0.9 g, n = 12, versus 4.5 +/- 0.4 g, n = 38, p < 0.0001 for ET and 6.5 +/- 1.9 g, n = 7, versus 1.7 +/- 0.3 g, n = 8, p = 0.015 for AII) and normalized force (0.95 +/- 0.1 g/mm versus 0.66 +/- 0.05 g/mm, p = 0.007 for ET-1 and 0.8 +/- 0.2 g/mm versus 0.2 +/- 0.05 g/mm, p < 0.01 for AII) in RA than in the internal mammary artery. There were no significant differences detected between these arteries with regard to either endothelium-dependent (to substance P and A23187) or endothelium-independent (to nitroglycerin) relaxation (p > 0.05). CONCLUSIONS: We conclude that the human RA has a higher receptor-mediated contractility (to ET-1 and AII) but similar endothelial function compared to the internal mammary artery. The study reveals the nature of the more spastic characteristics of the RA, supports the necessity of a more active pharmacologic intervention to relieve spasm in the RA, and suggests that the similar endothelium-derived relaxing factor-mediated endothelial function of the RA compared with the internal mammary artery may be the basis for a satisfactory long-term patency.

Angiotensin II↗

PubMed2003

Endogenous estrogens influence endothelial function in young men.

Males produce endogenous estrogen from testosterone via the enzyme aromatase. Previous studies have suggested a role for endogenous estrogens in cardiovascular function in men. We examined the effects of endogenous estrogen suppression via aromatase inhibition on endothelial function, systemic arterial compliance, and lipoprotein levels in healthy young men. Using a placebo-controlled double-blind randomized design, 20 healthy men, aged 18 to 32 years, were randomized to receive either the aromatase inhibitor anastrozole (1 mg) or matching placebo. Hormone, lipid levels, C-reactive protein (CRP), and homocysteine were measured. Endothelial function, determined by flow-mediated dilation of the brachial artery, and systemic arterial compliance were assessed at baseline and after 6 weeks of treatment. There was a significant decrease in 17beta-estradiol concentrations with aromatase inhibition, from 85.4+/-4.2 to 64.3+/-8.1 pmol/L (mean+/-SD, P=0.042). Compared with baseline, a significant decrease in flow-mediated dilation was observed in subjects taking anastrozole [median, 6.1% (range, 5.2 to 13.4) to 3.5% (2.0 to 5.7), P=0.034] but not in the placebo group. No changes were observed in nitroglycerin-induced endothelium-independent dilation in either group. There was no change in systemic arterial compliance with either aromatase therapy or placebo. There were no significant changes in lipoproteins, testosterone, DHEA, CRP, or homocysteine levels in either the anastrozole or placebo group. We conclude that suppression of endogenous estrogens with an aromatase inhibitor resulted in impairment of flow-mediated dilation without significant changes in lipoproteins, homocysteine, or CRP. Our results suggest that endogenous estrogens play a direct regulatory role in endothelial function in young healthy men.

Adolescent↗

PubMed2001

Coronary artery endothelial protection after local delivery of 17beta-estradiol during balloon angioplasty in a porcine model: a potential new pharmacologic approach to improve endothelial function.

OBJECTIVES: The goal of this research was to study the effect of locally delivered 17beta-estradiol (17beta-E) during angioplasty on endothelial function after percutaneous transluminal coronary angioplasty (PTCA) at four weeks. BACKGROUND: The endothelium plays a major role in the structural and functional integrity of coronary arteries and is damaged by PTCA. METHODS: Juvenile swine were subjected to PTCA, after which each artery was randomly-assigned to 600-microg 17beta-E delivered locally, an equal volume of vehicle (V) or PTCA alone. After four weeks, the improvement in endothelial function was assessed by angiography using intracoronary acetylcholine (Ach) infusion and by immunohistochemistry. RESULTS: At 10(-5) mol/l and 10(-4) mol/l Ach, significant vasoconstriction was noted in arteries treated with PTCA alone (p < 0.01 and p < 0.0001, respectively) and with PTCA plus V (p < 0.02 and p < 0.001, respectively). No significant vasoconstrictive response to Ach was observed in arteries treated with PTCA plus 17beta-E. Immunohistochemistry of vessels four weeks after PTCA revealed enhanced re-endothelialization (p < 0.0005) and endothelial nitric-oxide synthase (eNOS) expression (p < 0.0005) in PTCA plus 17beta-E-treated arteries compared with the other two treatment groups. Arteries treated with 17beta-E showed significantly lower neointima formation, which correlated inversely with the extent of re-endothelialization and eNOS expression. CONCLUSIONS: Locally delivered 17beta-E significantly enhances re-endothelialization and endothelial function after PTCA, possibly by improving the expression of eNOS. Since endothelial dysfunction can promote both restenosis and coronary spasm, local 17beta-E administration is a promising new approach to improve long-term results after PTCA.

Acetylcholine↗

PubMedDate not supplied

Folic acid treatment of hyperhomocysteinemia in peritoneal dialysis patients: no change in endothelial function after long-term therapy.

BACKGROUND: Hyperhomocysteinemia occurs in renal failure and may increase the risk for cardiovascular disease, possibly by damaging the endothelium. Folic acid and betaine are required in two separate homocysteine conversion pathways and may therefore lower plasma homocysteine. OBJECTIVE: To study the therapeutic role of betaine and the effect on endothelial function of long-term homocysteine-lowering therapy with folic acid, in peritoneal dialysis (PD) patients. PATIENTS AND DESIGN: Thirty PD patients were randomized to a 12-week treatment with 5 mg folic acid and 4 g betaine daily, or to 5 mg folic acid alone daily. They were then rerandomized to treatment with 1 or 5 mg folic acid daily for 40 weeks. MEASUREMENTS: At baseline and after 52 weeks, endothelial function was assessed by determination of endothelium-dependent vasodilatation and biochemical markers. RESULTS: Plasma total homocysteine (tHcy) was elevated at baseline: 42.6 (5.8) micromol/L. Only 1 patient (3%) had a normal plasma homocysteine (i.e., < or = 15 micromol/L) before therapy. Normalization of plasma homocysteine occurred in 39% of the patients at 12 weeks. Betaine had no additional homocysteine-lowering effect. Plasma tHcy levels were similar during treatment with 1 or 5 mg folic acid daily. Endothelial function was impaired at baseline and had not improved after 52 weeks of treatment. CONCLUSIONS: Peritoneal dialysis patients have hyperhomocysteinemia, which can be normalized with folic acid alone in about 40% of patients. Betaine does not further lower plasma homocysteine. A maintenance dose of 1 or 5 mg folic acid daily results in equivalent plasma homocysteine levels. Long-term reduction in plasma homocysteine did not result in improvement of endothelial function as assessed by our methods.

Betaine↗

PubMed1999

Long-term effects of combined hormone replacement therapy on markers of endothelial function and inflammatory activity in healthy postmenopausal women.

OBJECTIVE: To study the effects of combined hormone replacement therapy on markers of endothelial function and inflammatory activity. DESIGN: Prospective, randomized, controlled study. SETTING: Academic hospital. PATIENT(S): Healthy postmenopausal women with an intact uterus. INTERVENTION(S): For the first 12 months, the hormone replacement therapy group (n = 14) received oral E2, 1 mg daily, sequentially combined with 5 or 10 mg of dydrogesterone. Thereafter, they received oral E2, 2 mg daily, sequentially combined with 10 mg of dydrogesterone. The control group (n = 13) received no treatment. Data were collected at baseline and at 3, 12, and 15 months. MAIN OUTCOME MEASURE(S): Parameters of endothelial function and inflammatory activity. RESULT(S): During 12 months of follow-up, we observed decreases of 15% in plasma levels of endothelin-l, of 21% in soluble thrombomodulin, of 14% in von Willebrand factor, and of 12% in clottable fibrinogen in the hormone replacement therapy group compared with the control group. There was a 5% decrease in soluble E-selectin tevels. All significant changes were observed by 3 months and sustained after 15 months. Brachial artery flow-mediated vasodilatation and C-reactive protein levels did not change significantly. CONCLUSION(S): Long-term combined hormone replacement therapy with E2 and dydrogesterone in healthy women was associated with sustained improvement in some aspects of endothelial function and in clottable fibrinogen levels.

Dydrogesterone↗

PubMed2003

Raloxifene, conjugated oestrogen and endothelial function in postmenopausal women.

OBJECTIVES: To study the long-term effects of raloxifene, a potential designer oestrogen, and oestrogen monotherapy on endothelial function in healthy postmenopausal women. DESIGN: A 2-year double-blind, randomized and placebo-controlled study in an Academic Medical Center. Fifty-six hysterectomized but otherwise healthy postmenopausal women randomly received raloxifene hydrochloride 60 mg day-1 (n = 15) or 150 mg day-1 (n = 13), conjugated equine oestrogen (CEE) 0.625 mg day-1 (n = 15), or placebo (n = 13). MAIN OUTCOME MEASURES: Endothelial function as estimated from brachial artery flow-mediated, endothelium-dependent vasodilation and nitroglycerine-induced endothelium-independent vasodilation, and plasma levels of the endothelium-derived regulatory proteins, von Willebrand factor (vWF) and endothelin (ET). RESULTS: Raloxifene 60 mg did not significantly affect endothelial function. As compared with placebo, at 6 months of therapy, raloxifene 150 mg and CEE were associated with a mean increase in vWF of 25.5% point (95% CI 3.6-47.3) and 26.6% point (95% CI 6.9-46.3), respectively. At 24 months of therapy, raloxifene 150 mg was associated with a mean decrease in ET of 0.96 pg mL-1 (95% CI -1.57 to -0.36). Raloxifene nor CEE significantly affected endothelium-dependent and/or -independent vasodilation. CONCLUSIONS: Our results suggest that long-term therapy with raloxifene or oral CEE does not affect endothelium-dependent vasodilation in healthy postmenopausal women. Raloxifene 150 mg day-1 might have both positive and negative effects on endothelium. The clinical significance of these findings remains to be investigated.

Analysis of Variance↗

PubMed2000

Atorvastatin but not L-arginine improves endothelial function in type I diabetes mellitus: a double-blind study.

OBJECTIVES: We sought to determine the effects of oral L-arginine and the hexamethylglutaryl coenzyme A reductase inhibitor atorvastatin on endothelial function in young patients with type I diabetes mellitus (DM). BACKGROUND: Endothelial dysfunction, a key early event in atherosclerosis, occurs in young patients with type I DM, and its reversal may benefit the progression of vascular disease. Cholesterol reduction in L-arginine improve endothelial function in nondiabetic subjects, but their effect in patients with type I DM is unknown. METHODS: In a double-blind, 2x2 factorial study, we investigated the effect of L-arginine (7 g twice daily) and atorvastatin (40 mg/day) on conduit artery vascular function in 84 normocholesterolemic young adults (mean+/-SD: age 34 years [range 18 to 46], low density lipoprotein [LDL] cholesterol 2.96+/-0.89 mmol/liter) with type I DM. Brachial artery dilation to flow (flow-mediated dilation [FMD]) and to the direct smooth muscle dilator glyceryl trinitrate (GTN) were assessed noninvasively using high resolution ultrasound at baseline and after six weeks of treatment. RESULTS: Atorvastatin resulted in a 48+/-10% decrease in serum LDL cholesterol levels, whereas L-arginine levels increased by 247+/-141% after L-arginine therapy. By analysis of covariance, treatment with atorvastatin resulted in a significant increase in FMD (p = 0.018. L-Arginine therapy had no significant effect on endothelial function, and there was no significant change in dilation to GTN after either intervention. CONCLUSIONS: In young patients with type I DM, improvement in endothelial dysfunction can be demonstrated after just six weeks of treatment with atorvastatin. In contrast to studies of hypercholesterolemia, however, L-arginine had no benefit. Treatment with atorvastatin at an early stage may have an impact on the progression of atherosclerosis in these high risk patients.

Adolescent↗

PubMed2005

Conjugated linoleic acid impairs endothelial function.

OBJECTIVE: To determine the effect of dietary supplementation with conjugated linoleic acid (CLA) on body mass index (BMI), body fat distribution, endothelial function, and markers of cardiovascular risk. METHODS AND RESULTS: Forty healthy volunteers with BMI >27 kg/m2 were randomized to receive a CLA isomeric mixture or olive oil in a 12-week double-blind study. Subcutaneous body fat and abdominal/hepatic fat content were assessed using skin-fold thicknesses and computed tomography scanning, respectively. Endothelial function was assessed by brachial artery flow-mediated dilatation (FMD). Plasma isoprostanes were measured as an index of oxidative stress. CLA supplementation did not result in a significant change in BMI index or total body fat. There was a significant decrease in limb (-7.8 mm, P<0.001), but not torso skin-fold thicknesses or abdominal or liver fat content. Brachial artery FMD declined (-1.3%, P=0.013), and plasma F2-isoprostanes increased (+91 pg/mL, P=0.042). CONCLUSIONS: A CLA isomeric mixture had at most modest effects on adiposity and worsened endothelial function. On the basis of these results, the use of the isomeric mixture of CLA as an aid to weight loss cannot be recommended.

Adult↗

PubMed2006

Peripheral fibrinolytic markers, soluble adhesion molecules, inflammatory cytokines and endothelial function in hypopituitary adults with growth hormone deficiency.

BACKGROUND: Increased mortality due to cardiovascular disease has been described in adult patients with untreated GH deficiency (GHD). GH replacement has been demonstrate to improve vascular reactivity and reverse early atherosclerotic changes in adults with GHD. OBJECTIVE: Assessment of fibrinolytic markers, soluble adhesion molecules, inflammatory cytokines and endothelial function in hypopituitary adults with GHD at baseline and 1 year after GH replacement therapy. METHODS: We studied 10 patients with GHD (five men and five women; aged 45.6 +/- 10.4 years) at baseline and 1 year after GH replacement therapy compared with a control group (nine men and 16 women) matched for age and body mass index (BMI). All subjects, patients and controls, were life-long nonsmokers, normotensive and nondiabetic. The following variables were recorded: anthropometric and body composition variables, serum concentrations of glucose, insulin and C-peptide; thrombin anti-thrombin (TAT) fragments and fibrin degradation product D-dimer, which were determined by an enzyme-linked immunosorbent assay (ELISA); IGF-I by radioimmunoassay (RIA); C-reactive protein (CRP) by highly sensitive immunonephelometry; E-selectin, P-selectin, soluble intercellular cell adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) by ELISA. The assessment of endothelial function in vivo was measured with a Doppler device. RESULTS: Patients with GHD without GH substitution had higher hip/waist ratio and body fat than controls. Insulin, C-peptide and triglyceride concentrations were also higher. Our results demonstrated no difference in fibrinogen and in TAT fragment concentrations among patients and controls. E-selectin concentrations were higher in patients than in controls (26.1 +/- 11 vs. 10.7 +/- 6.2 microg/l, P = 0.0001). P-selectin, sICAM-1, sVCAM-1, IL-6, MCP-1 and CRP were similar in the two groups. Vascular reactivity and carotid intima-media thickness (IMT) were also similar in patients and controls. After 1 year of GH treatment we found no changes in biochemical parameters, fibrinolytic markers, soluble adhesion molecules, inflammatory cytokines and endothelial function. CONCLUSION: Adults with GHD show some subtle changes in soluble adhesion molecules but our data suggest no beneficial effects of GH over these markers in relationship to endothelial function. Factors other than GH treatment, such as differences in age, degree of obesity, the presence of diabetes mellitus and arterial hypertension or tobacco consumption, could explain the observed increase in markers of vascular risk in GH-deficient patients.

Adult↗

PubMed2002

Folic acid improves endothelial function in coronary artery disease via mechanisms largely independent of homocysteine lowering.

BACKGROUND: Homocysteine is a risk factor for coronary artery disease (CAD), although a causal relation remains to be proven. The importance of determining direct causality rests in the fact that plasma homocysteine can be safely and inexpensively reduced by 25% with folic acid. This reduction is maximally achieved by doses of 0.4 mg/d. High-dose folic acid (5 mg/d) improves endothelial function in CAD, although the mechanism is controversial. It has been proposed that improvement occurs through reduction in total (tHcy) or free (non-protein bound) homocysteine (fHcy). We investigated the effects of folic acid on endothelial function before a change in homocysteine in patients with CAD. METHODS AND RESULTS: A randomized, placebo-controlled study of folic acid (5 mg/d) for 6 weeks was undertaken in 33 patients. Endothelial function, assessed by flow-mediated dilatation (FMD), was measured before, at 2 and 4 hours after the first dose of folic acid, and after 6 weeks of treatment. Plasma folate increased markedly by 1 hour (200 compared with 25.8 nmol/L; P<0.001). FMD improved at 2 hours (83 compared with 47 microm; P<0.001) and was largely complete by 4 hours (101 compared with 51 microm; P<0.001). tHcy did not significantly differ acutely (4-hour tHcy, 9.56 compared with 9.79 micromol/L; P=NS). fHcy did not differ at 3 hours but was slightly reduced at 4 hours (1.55 compared with 1.78 micromol/L; P=0.02). FMD improvement did not correlate with reductions in either fHcy or tHcy at any time. CONCLUSIONS: These data suggest that folic acid improves endothelial function in CAD acutely by a mechanism largely independent of homocysteine.

Coronary Artery Disease↗

PubMed2006

Cigarette smoking induced oxidative stress may impair endothelial function and coronary blood flow in angiographically normal coronary arteries.

BACKGROUND: Smoking contributes to the progression of atherosclerotic heart disease by causing endothelial dysfunction. In the present study the effect of smoking on endothelial functions and coronary flow was investigated, as well as the relationship of these factors with oxidative stress parameters, in subjects with normal coronary arteries. MATERIALS AND RESULTS: The study group comprised 87 patients with angiographically normal coronary arteries (36 smokers, 51 nonsmokers). Coronary flow patterns were determined by the Thrombolysis In Myocardial Infarction (TIMI) frame count method. Endothelial function was evaluated by high-frequency ultrasound imaging of the brachial artery. Superoxide dismutase (SOD) and reduced glutathione (GSH) and reduction of oxidative material in the body and the endproduct of lipid peroxidation, malondialdehyde (MDA), were measured as oxidative stress markers. Mean TIMI frame count was significantly higher in smokers than nonsmokers (42.2 +/- 16 vs 29.5 +/- 9.5, p = 0.0001). Endothelium-dependent flow-mediated dilatation was 6.81+/-1.95% in nonsmokers and 5.7 +/- 2.2% in smokers (p = 0.0001). The smokers had dramatically higher levels of SOD and MDA and lower levels of GSH than the nonsmoker group. CONCLUSION: Smoking induced oxidative stress deteriorates coronary blood flow by disturbing endothelial function.

Adult↗

PubMed2006

Plasma homocysteine, oxidative stress and endothelial function in patients with Type 1 diabetes mellitus and microalbuminuria.

AIMS: The purpose of this study was to examine the associations between endothelial function, plasma homocysteine and oxidative stress in patients with Type 1 diabetes mellitus (DM) and microalbuminuria compared with DM patients with normoalbuminuria and non-diabetic control subjects. We wished to test the hypothesis that increased cardiovascular risk in patients with Type 1 diabetes and microalbuminuria may be in part as a result of hyperhomocysteinaemia-mediated oxidative stress leading to impaired endothelial function. METHODS: We measured forearm blood flow, total plasma homocysteine, total antioxidant status (TAOS) and whole blood glutathione in 31 DM patients, 16 with microalbuminuria and 15 with normoalbuminuria, and 15 non-diabetic control subjects. RESULTS: Plasma homocysteine levels were significantly higher in the microalbuminuric diabetic patients compared with the normoalbuminuric patients and the control subjects. TAOS was significantly lower in the micoalbuminuric and normoalbuminuric diabetic patients compared with the control subjects, although TAOS levels were similar in both groups of diabetic patients. There was no difference in forearm blood flow between the groups and no association between measured endothelial function and antioxidant defence/oxidative stress and homocysteine in each group. There was no association between plasma total homocysteine and TAOS or whole blood glutathione within the groups. CONCLUSIONS: We have found mild hyperhomocysteinaemia in microalbuminuric DM patients compared with normoalbuminuric DM patients and non-diabetic subjects and some evidence for reduced antioxidant defence in DM patients. These findings add to our understanding of the increased risk of vascular disease in patients with Type 1 diabetes.

Adult↗

PubMed2002

5-methyltetrahydrofolate restores endothelial function in uraemic patients on convective haemodialysis.

BACKGROUND: Hyperhomocysteinaemia is an independent risk factor for the development of atherosclerosis. In patients with chronic renal failure, the administration of folic acid or its metabolites reduces but does not normalize plasma homocysteine concentrations. Furthermore, homocysteine induces endothelial dysfunction by an increased inactivation of nitric oxide. METHODS: We examined the effect of the active metabolite of folic acid, 5-methyltetrahydrofolate (5-MTHF), 45 mg/week i.v. for 10 weeks, combined during the last 2 weeks with vitamin B12, 500 microg s.c. twice weekly, on homocysteinaemia and endothelial function in 15 patients undergoing convective haemodialysis. Endothelial function was evaluated by B-mode ultrasonography on the brachial artery. Flow-mediated dilation (FMD) was recorded during reactive hyperaemia produced by inflation of a pneumatic tourniquet. Nitroglycerine-mediated dilation (NMD) was recorded after administration of isosorbide dinitrate. Finally, the presence of the thermolabile variant of methyltetrahydrofolate reductase (t-MTHFR) was assessed by genotype analysis. RESULTS: Plasma homocysteine concentrations fell by 47% after treatment with 5-MTHF alone and by a further 13.6% after the addition of vitamin B12. The reduction was more marked in homo- and heterozygous patients than in normal genotypes for t-MTHFR. Flow-mediated endothelial vasodilation, measured by ultrasonography of the brachial artery, improved after administration of 5-MTHF (12.52+/- 2.47% vs. 7.03+/-1.65%; P<0.05), but there were no further changes following the addition of vitamin B12. CONCLUSIONS: Our study demonstrated that 5-MTHF administration not only reduced plasma homocysteine but also improved endothelial function in uraemic patients undergoing convective haemodialysis.

Drug Therapy, Combination↗

PubMed2002

Eicosapentaenoic acid improves endothelial function in hypertriglyceridemic subjects despite increased lipid oxidizability.

BACKGROUND: Epidemiologic investigations suggest that fish oil, which contains eicosapentaenoic acid (EPA), has favorable cardiovascular effects. Fish oil improves endothelial function in subjects with hypercholesterolemia or diabetes. However, controversy persists regarding relationships between primary hypertriglyceridemia and endothelial dysfunction. Moreover, lipoproteins are more susceptible to oxidation in vitro after incorporation of fish oil. METHODS: We determined the effects of EPA on serum lipids, susceptibility of low-density lipoproteins (LDL) and very-low-density lipoproteins (VLDL) to oxidation, and endothelial function in hypertriglyceridemic (HTG) subjects. In 8 men with untreated primary hypertriglyceridemia (plasma triglyceride between 150 and 500 mg/dL) and 7 control subjects (triglyceride below 150 mg/dL), forearm blood flow (FBF) responses were tested. In HTG subjects, this was repeated 3 months after initiation of EPA (1800 mg/day). Cu2+-induced oxidation of VLDL and LDL was determined by serial measurement of conjugated dienes. We used lag time, which corresponded to the period when the lipoproteins were resistant to oxidation, as a parameter of oxidizability. FBF responses to acetylcholine and sodium nitroprusside were determined by strain-gauge plethysmography. RESULTS: Plasma triglyceride in HTG subjects fell 31% with EPA supplementation. Before EPA, VLDL and LDL lag times in HTG subjects were shorter than in control subjects. EPA further reduced lag time for VLDL but not LDL. The FBF response to acetylcholine (but not to nitroprusside) was significantly less in HTG subjects before EPA than in control subjects. EPA normalized the FBF response to acetylcholine. CONCLUSIONS: EPA improves endothelial function in HTG subjects despite increasing in VLDL oxidizability.

Acetylcholine↗

PubMed2003

Improved endothelial function after a modified harvesting technique of the internal thoracic artery.

OBJECTIVE: One of the most important factors in bypass surgery is the preservation of endothelial function in the arterial graft. It was of interest, therefore, whether a slightly modified preparation procedure during surgery could contribute to improved endothelial function of the graft. We compared the functional activity of internal thoracic arteries (ITA) prepared according to the traditional harvesting method with occlusion by a clip, dissection at the distal end and storage of the artery in papaverine until its implantation (CA) with the functional activity of arteries which were also prepared and wrapped in papaverine, but were left perfused and dissected immediately before their anastomoses (PA). METHODS: Samples of ITA were obtained from a total number of 28 patients, undergoing bypass surgery, and randomly distributed into two groups. The arteries were cut into rings and suspended in organ baths, containing Krebs-Henseleit solution, for isometric tension recording. Cumulative concentration response curves were determined for the contractile agents endothelin-1 (ET-1), 5-hydroxytryptamine (5-HT), noradrenaline (NA) and potassium chloride (KCl) and the relaxant compounds acetylcholine (ACH) and sodium nitroprusside (SNP) during active tone induced by 30 mM KCl. RESULTS: ET-1 and 5-HT stimulated rings from both groups within the same concentration ranges but elicited significantly (P<0.05) higher contractile responses in CA compared to PA. By contrast, concentration response curves for KCl and NA where nearly superimposable. On the other hand, maximal endothelium-dependent relaxant responses to ACH proved to be significantly stronger in PA (0.84+/-0.20 g) as compared to CA (0.31+/-0.05 g, P<0.05) while endothelium independent relaxant responses to SNP where similar in both groups. CONCLUSION: These data suggest that leaving the ITA perfused during harvesting might improve considerably the endothelial function of the graft.

Acetylcholine↗

PubMed2002

Assessment of endothelial function using peripheral waveform analysis: a clinical application.

OBJECTIVES: The study was done to determine whether radial artery applanation tonometry can be used as a noninvasive method of assessing global endothelial function. BACKGROUND; It is known that beta(2)-receptor stimulation results in endothelial release of nitric oxide. Furthermore, for over a century glyceryl trinitrate (GTN) has been known to markedly affect the arterial pressure waveform, even in the absence of significant blood pressure (BP) changes. Therefore, it was hypothesized that the change in the peripheral pressure waveform, as measured using tonometry and quantified using the augmentation index (AIx) and in response to Salbutamol (Salb), would allow assessment of global endothelial function. METHODS: The study contained three parts. In the first study, Salb (400 microg) was administered to 11 healthy subjects via inhalation after either intravenous N-omega-nitro-monomethyl-L-arginine (L-NMMA) (3 mg/kg over 5 min) or control solution (normal saline) in the supine, rested, fasted condition. The BP, heart rate and waveform responses were recorded each 5 min following Salb for 20 min. Next, GTN was given and responses recorded 5 min later. In the second study, both the reproducibility of Salb and the GTN responses were assessed in 9 subjects studied twice on separate days. In the third study, the Salb and GTN responses of 12 subjects with angiographic coronary artery disease (CAD) were compared with 10 age-matched control subjects with no atherosclerotic risk factors. RESULTS: After control infusion, AIx decreased following Salb, from 50.8 +/- 4.3% to 44.8 +/- 4.2%, a change of -11.8 +/- 3.7%, p < 0.01. After L-NMMA, AIx did not significantly change following Salb (54.2 +/- 5.1% vs. 52.9 +/- 5.3%, -2.0 +/- 3.1%). The GTN-induced decreases in AIx were similar after either infusion (35.1 +/- 3.3% vs. 36.5 +/- 3.3%). Reproducibility of Salb-induced changes in AIx between studies performed on separate days was good (r = 0.80, p < 0.01). Salb-induced changes in AIx in CAD patients were significantly less compared to control subjects (-2.4 +/- 1.9% vs. -13.2 +/- 2.4%, respectively, p < 0.002). The GTN-induced changes were not significantly different (-27.6 +/- 4.2 vs. -38.9 +/- 4.4%, p = 0.07). CONCLUSIONS: The peripheral arterial pressure waveform is sensitive to beta(2)-stimulation. Changes are related to nitric oxide release, are reproducible and can distinguish between clinical subject groups. Arterial waveform changes following Salb may thus provide a noninvasive method of measuring "global" arterial endothelial function.

Adrenergic beta-Agonists↗

PubMed2026

Effects of semaglutide and empagliflozin on markers of endothelial function in persons with type 2 diabetes: A post hoc analysis of a randomized clinical trial.

AIMS: The endothelium maintains vascular health by regulating blood flow and protecting against inflammatory damage. In type 2 diabetes (T2DM), however, hyperglycemia, hypertension, and hyperlipidemia place a significant burden on the endothelium, potentially leading to atherosclerosis and cardiovascular disease (CVD). While semaglutide and empagliflozin have been shown to reduce CVD risk in T2DM, it remains unclear whether these benefits are mediated by improved endothelial function. This post-hoc analysis explores the effects of these agents on markers of endothelial function, i.e. the reactive hyperaemic index (RHI) and the endothelial-derived cell adhesion molecules (CAMs) E-Selectin, ICAM-1, P-Selectin, and VCAM-1. METHODS: This was a post-hoc analysis of a 32-week randomized trial evaluating the separate and combined effects of semaglutide and empagliflozin on cardio-renal organ damage. One hundred and twenty participants with type 2 diabetes, age ≥ 50 were randomized to four groups (semaglutide, empagliflozin, the combination or placebo). An increase in RHI and/or a decrease in CAMs were considered beneficial. RESULTS: RHI increased compared to baseline (0.11, 95%CI [0.008;0.21], p = 0.03) but not compared to placebo in the semaglutide group (0.11, 95%CI [-0.04;0.24], p = 0.16). There was no effect on RHI in the empagliflozin group. Compared to placebo, E-Selectin decreased significantly in the semaglutide and combination groups (-9, 95%CI [-14.1;-5.1] p < 0.01 and - 9, 95%CI [-14.3; -5.2] p < 0.01, respectively). VCAM-1 increased in the same groups, compared to placebo (12.3, 95%CI[2.8;20.8] p = 0.01 and 16.2, 95%CI [7.2;24.3], p < 0.01, respectively).P-Selectin and ICAM-1 was not significantly affected in any of the groups, compared to placebo (p ≥ 0.11 and p ≥ 0.09, respectively). CONCLUSION: Semaglutide improved endothelial function compared to baseline, but not significantly versus placebo, which likely is due to limited power. CAM responses were heterogeneous, suggesting distinct roles in endothelial dysfunction and atherosclerosis. ClinicalTrialsRegister.eu: EudraCT 2019-000781-38.

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