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Folic acid ingestion improves skeletal muscle blood flow during graded handgrip and plantar flexion exercise in aged humans.
Romero, SA, Gagnon, D, Adams, AN, Moralez, G, Kouda, K, Jaffery, MF, Cramer, MN, Crandall, CG
American journal of physiology. Heart and circulatory physiology. 2017;(3):H658-H666
Abstract
Skeletal muscle blood flow is attenuated in aged humans performing dynamic exercise, which is due, in part, to impaired local vasodilatory mechanisms. Recent evidence suggests that folic acid improves cutaneous vasodilation during localized and whole body heating through nitric oxide-dependent mechanisms. However, it is unclear whether folic acid improves vasodilation in other vascular beds during conditions of increased metabolism (i.e., exercise). The purpose of this study was to test the hypothesis that folic acid ingestion improves skeletal muscle blood flow in aged adults performing graded handgrip and plantar flexion exercise via increased vascular conductance. Nine healthy, aged adults (two men and seven women; age: 68 ± 5 yr) performed graded handgrip and plantar flexion exercise before (control), 2 h after (acute, 5 mg), and after 6 wk (chronic, 5 mg/day) folic acid ingestion. Forearm (brachial artery) and leg (superficial femoral artery) blood velocity and diameter were measured via Duplex ultrasonography and used to calculate blood flow. Acute and chronic folic acid ingestion increased serum folate (both P < 0.05 vs. control). During handgrip exercise, acute and chronic folic acid ingestion increased forearm blood flow (both conditions P < 0.05 vs. control) and vascular conductance (both P < 0.05 vs. control). During plantar flexion exercise, acute and chronic folic acid ingestion increased leg blood flow (both P < 0.05 vs. control), but only acute folic acid ingestion increased vascular conductance (P < 0.05 vs. control). Taken together, folic acid ingestion increases blood flow to active skeletal muscle primarily via improved local vasodilation in aged adults.NEW & NOTEWORTHY Our findings demonstrate that folic acid ingestion improves blood flow via enhanced vascular conductance in the exercising skeletal muscle of aged humans. These findings provide evidence for the therapeutic use of folic acid to improve skeletal muscle blood flow, and perhaps exercise and functional capacity, in human primary aging.Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/folic-acid-and-exercise-hyperemia-in-aging/.
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Oral treatment with nicorandil at discharge is associated with reduced mortality after acute myocardial infarction.
Sakata, Y, Nakatani, D, Shimizu, M, Suna, S, Usami, M, Matsumoto, S, Hara, M, Sumitsuji, S, Kawano, S, Iwakura, K, et al
Journal of cardiology. 2012;(1):14-21
Abstract
BACKGROUND Previous studies showed that nicorandil can reduce coronary events in patients with coronary artery disease. However, it is unclear whether oral nicorandil treatment may reduce mortality following acute myocardial infarction (AMI). METHODS AND RESULTS We examined the impact of oral nicorandil treatment on cardiovascular events in 1846 AMI patients who were hospitalized within 24 h after AMI onset, treated with emergency percutaneous coronary intervention (PCI), and discharged alive. Patients were divided into those with (Group N, n=535) and without (Group C, n=1311) oral nicorandil treatment at discharge. No significant differences in age, gender, body mass index, prevalence of coronary risk factors, or history of myocardial infarction existed between the two groups; however, higher incidences of multi-vessel disease, and a lower rate of successful PCI were observed in Group N. During the median follow-up of 709 (340-1088) days, all-cause mortality rate was 43% lower in Group N compared with Group C (2.4% vs. 4.2%, stratified log-rank test: p=0.0358). Multivariate Cox regression analysis revealed that nicorandil treatment was associated with all-cause death after discharge (Hazard ratio 0.495, 95% CI: 0.254-0.966, p=0.0393), but not for other cardiovascular events such as re-infarction, admission for heart failure, stroke and arrhythmia. CONCLUSIONS The results suggest that oral administration of nicorandil is associated with reduced incidence of death in the setting of secondary prevention after AMI.
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The association between microvascular and macrovascular endothelial function in patients with rheumatoid arthritis: a cross-sectional study.
Sandoo, A, Carroll, D, Metsios, GS, Kitas, GD, Veldhuijzen van Zanten, JJ
Arthritis research & therapy. 2011;(3):R99
Abstract
INTRODUCTION Patients with rheumatoid arthritis (RA) are at an increased risk for cardiovascular disease (CVD). One of the earliest manifestations of CVD is endothelial dysfunction (ED). ED can occur in both the microcirculation and the macrocirculation, and these manifestations might be relatively independent of each other. Little is known about the association between endothelial function in the microcirculation and the macrocirculation in RA. The objectives of the present study were to examine the relationship between microvascular and macrovascular endothelial function in patients with RA. METHODS Ninety-nine RA patients (72 females, mean age (± SD) 56 ± 12 years), underwent assessments of endothelial-dependent (acetylcholine) and endothelial-independent (sodium nitroprusside) microvascular vasodilatory function (laser Doppler imaging with iontophoresis), as well as endothelial-dependent (flow-mediated dilation) and endothelial-independent (glyceryl trinitrate-mediated dilation) macrovascular vasodilatory function. Vasodilatory function was calculated as the percentage increase after each stimulus was applied relative to baseline values. RESULTS Pearson correlations showed that microvascular endothelial-dependent function was not associated with macrovascular endothelial-dependent function (r (90 patients) = 0.10, P = 0.34). Similarly, microvascular endothelial-independent function was not related to macrovascular endothelial-independent function (r (89 patients) = 0.00, P = 0.99). CONCLUSIONS Microvascular and macrovascular endothelial function were independent of each other in patients with RA, suggesting differential regulation of endothelial function in these two vascular beds. Assessments of both vascular beds may provide more meaningful clinical information on vascular risk in RA, but this hypothesis needs to be confirmed in long-term prospective studies.
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Acute effects of intravenous nicorandil on hemodynamics in patients hospitalized with acute decompensated heart failure.
Tanaka, K, Kato, K, Takano, T, Katagiri, T, Asanoi, H, Nejima, J, Nakashima, M, Kamijo, T, Sakanashi, M
Journal of cardiology. 2010;(3):291-9
Abstract
BACKGROUND Nicorandil injection, a potent vasodilator with K(ATP) channel opening action and nitrate-like action, has been used for treatment of unstable angina. In the present investigation, we examined the effect of intravenous nicorandil on hemodynamics in patients with acute decompensated heart failure (ADHF). METHODS ADHF patients admitted to hospital with pulmonary artery wedge pressure (PAWP)≥18 mm Hg were enrolled. Patients received nicorandil by an intravenous bolus injection of 0.2mg/kg/5 min followed by continuous infusion at a rate of 0.05, 0.10, or 0.20mg/kg/h for 6h. RESULTS Nicorandil administration caused a significant decrease in PAWP and increase in the cardiac index (CI) that began immediately after the injection and were maintained during the continuous infusion. After 6h, nicorandil administration at 0.2mg/kg/5 min followed by 0.20mg/kg/h resulted in a decrease in PAWP (26.5%, p<0.01), an increase in CI (15.8%, p<0.05), and a decrease in total peripheral resistance (13.8%, p<0.01) in a dose-dependent manner. Nicorandil decreased blood pressure significantly, without an excessive decrease or negative impact even in patients with lower systolic blood pressure. CONCLUSION Intravenous administration of nicorandil, by bolus injection followed by continuous infusion, improves PAWP and CI in ADHF patients immediately and continuously as a potent vasodilator with combined preload and afterload reduction. These results demonstrate that nicorandil is a safe and effective new medication for the treatment of ADHF.
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Effects of long-acting beraprost sodium (TRK-100STP) in Japanese patients with pulmonary arterial hypertension.
Kunieda, T, Nakanishi, N, Matsubara, H, Ohe, T, Okano, Y, Kondo, H, Nishimura, M, Shirato, K, Tanabe, N, Homma, S, et al
International heart journal. 2009;(4):513-29
Abstract
The long-acting beraprost preparation TRK-100STP is formulated to provide sustained release of an orally active prostacyclin derivative to maintain the optimal plasma concentration for a longer period of time compared with the currently used conventional beraprost sodium. In the present study, we evaluated the efficacy of this newly developed formulation for pulmonary arterial hypertension (PAH).An open-label, 12-week multicenter clinical trial was performed in 46 patients with PAH. They were initially treated with 120 microg of TRK-100STP divided into 60 microg twice daily, followed by a stepwise increase to 360 microg given as 180 microg twice daily. The 6-minute walking distance showed a significant increase by 33.4+/-66.0 m (95% confidence interval [CI], 13.4 to 53.5) from the baseline measurement. Mean pulmonary artery pressure, total pulmonary vascular resistance, and pulmonary vascular resistance decreased by -2.8+/-5.5 mmHg (95% CI, -4.6 to -1.0), by -0.92+/-2.63 mmHg*L(-1)*min (95% CI, -1.78 to -0.05), and by -0.89+/-2.81 mmHg*L(-1)*min (95% CI, -1.84 to 0.06), respectively, from the baseline measurements. A higher efficacy was observed in patients with a maximum tolerated dose of 360 microg daily than those of 240 microg daily or less.Treatment with TRK-100STP for a 12-week period improved the exercise capacity, mean pulmonary artery pressure, and total pulmonary vascular resistance. TRK-100STP was effective for Japanese patients with PAH.
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N-acetylcysteine infusion improves hepatic perfusion in the early stages of systemic sclerosis.
Rosato, E, Zardi, EM, Barbano, B, Menghi, G, Cianci, R, Amoroso, A, Afeltra, A, Pisarri, S, Salsano, F
International journal of immunopathology and pharmacology. 2009;(3):763-72
Abstract
The aim of our study is to evaluate portal and hepatic hemodynamic changes after N-acetylcysteine infusion in patients with systemic sclerosis. In an open-label study 40 patients with systemic sclerosis (SSc) were treated with 15 mg/kg/hour intravenous N-acetylcysteine for 5 consecutive hours in a single day. Hepatic flow volume, congestion index, portal flow volume, resistance index and pulse rate index were measured in each subject before and after infusion. In all patients mean hepatic flow volume (HFV) and mean portal flow volume (PFV) values after the five-hour infusion with NAC increased not significantly. In 22 selected patients with active capillaroscopic pattern, modified Rodnan Total Skin Score (mRTSS)<18 and mild-moderate score to vascular domain of disease severity scale (DSS), mean HFV increased significantly when compared with mean HFV of 18 SSc patients with late capillaroscopic pattern, mRTSS>18 and severe-end stage score to vascular domain of DSS. The results of our study demonstrate that NAC is able to increase HFV and total liver perfusion after a single infusion in SSc patients with low disease activity and severity scores.
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Impaired endothelium-dependent vasodilation in overweight and obese adult humans is not limited to muscarinic receptor agonists.
Van Guilder, GP, Stauffer, BL, Greiner, JJ, Desouza, CA
American journal of physiology. Heart and circulatory physiology. 2008;(4):H1685-92
Abstract
Muscarinic receptor agonists have primarily been used to characterize endothelium-dependent vasodilator dysfunction with overweight/obesity. Reliance on a single class of agonist, however, yields limited, and potentially misleading, information regarding endothelial vasodilator capacity. The aims of this study were to determine 1) whether the overweight/obesity-related reduction in endothelium-dependent vasodilation extends beyond muscarinic receptor agonists and 2) whether the contribution of nitric oxide (NO) to endothelium-dependent vasodilation is reduced in overweight/obese adults. Eighty-six middle-aged and older adults were studied: 42 normal-weight (54 +/- 1 yr, 21 men and 21 women, body mass index = 23.4 +/- 0.3 kg/m(2)) and 44 overweight/obese (54 +/- 1 yr, 28 men and 16 women, body mass index = 30.3 +/- 0.6 kg/m(2)) subjects. Forearm blood flow (FBF) responses to intra-arterial infusions of acetylcholine in the absence and presence of the endothelial NO synthase inhibitor N(G)-monomethyl-l-arginine, methacholine, bradykinin, substance P, isoproterenol, and sodium nitroprusside were measured by strain-gauge plethysmography. FBF responses to each endothelial agonist were significantly blunted in the overweight/obese adults. Total FBF (area under the curve) to acetylcholine (50 +/- 5 vs. 79 +/- 4 ml/100 ml tissue), methacholine (55 +/- 4 vs. 86 +/- 5 ml/100 ml tissue), bradykinin (62 +/- 5 vs. 85 +/- 4 ml/100 ml tissue), substance P (37 +/- 4 vs. 57 +/- 5 ml/100 ml tissue), and isoproterenol (62 +/- 4 vs. 82 +/- 6 ml/100 ml tissue) were 30%-40% lower in the overweight/obese than normal-weight adults. N(G)-monomethyl-l-arginine significantly reduced the FBF response to acetylcholine to the same extent in both groups. There were no differences between the groups in the FBF responses to sodium nitroprusside. These results indicate that agonist-stimulated endothelium-dependent vasodilation is universally impaired with overweight/obesity. Moreover, this impairment appears to be independent of NO.
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The effects of sildenafil on ocular blood flow.
Koksal, M, Ozdemir, H, Kargi, S, Yesilli, C, Tomaç, S, Mahmutyazicioglu, K, Mungan, A
Acta ophthalmologica Scandinavica. 2005;(3):355-9
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Abstract
PURPOSE To investigate the effects of sildenafil, a popular new drug in the treatment of erectile dysfunction, on ocular blood flow. METHODS This study was designed as a prospective, double-blind, placebo-controlled study. Twenty participants with erectile dysfunction were given a single oral dose of 100 mg sildenafil, while 10 participants with erectile dysfunction were given placebo. All the participants underwent routine systemic and ophthalmological examinations. Intraocular pressure, systolic and diastolic blood pressure and ocular blood flow (ophthalmic, central retinal, short posterior ciliary arteries) were measured in both eyes before and 1 hour after the dose of sildenafil or placebo. Ocular blood flow measurements were performed using colour Doppler ultrasonography. RESULTS None of the parameters were significantly different between the groups before study drug intake. Although central retinal artery velocities were not changed, ophthalmic artery and short posterior ciliary artery peak systolic velocity, end-diastolic velocity, and mean velocity values were significantly increased 1 hour after drug intake in the sildenafil group compared to the placebo group (p < 0.05). CONCLUSION Sildenafil causes a significant increase in blood flow in these arteries. A possible role of inhibition of phosphodiesterase-5 in vascular smooth muscles by sildenafil is implicated. Further studies are needed to investigate the effects of sildenafil on ocular blood flow in patients with senile macular degeneration, diabetic retinopathy and glaucoma.
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Vasodilator effect of endothelin in cutaneous microcirculation of heart failure patients.
Andersson, SE, Edvinsson, ML, Alving, K, Edvinsson, L
Basic & clinical pharmacology & toxicology. 2005;(2):80-5
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The heart failure syndrome is associated with a reduced vasodilatory capacity in cutaneous microvessels. The aim of this study was to investigate the hypothesis that an altered activity of the endothelin system contributes to this reduction. The skin blood flow was recorded by laser Doppler flowmetry in patients with congestive heart failure and in age- and gender-matched controls without clinical signs of heart failure. The vessels were stimulated by iontophoretic administration of endothelin-1. The involvement of the endothelin(A) receptor was studied by co-administration of a specific antagonist; the role of the endothelin(B) receptor was studied by the administration of the selective agonist sarafotoxin 6c. The plasma levels of endothelin-1, C-reactive peptide and N-terminal-pro-Brain Natriuretic Peptide were elevated in heart failure patients. Unexpected, endothelin-1 induced an endothelin(A) mediated vasodilation. In the heart failure group the dilation was reduced to less than half as compared to control. The response to local warming was reduced in parallel indicating that the attenuation of the response in the heart failure group can be explained by the general decline in vascular reactivity. The response to endothelin(B) receptor stimulation did not differ between the groups. The reduction in endothelin-1 responsiveness is paralleled by a general reduction in microvascular vasodilatory capacity, a phenomenon of increased vascular stiffness in the of heart failure subjects.
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Effect of nimodipine on ocular blood flow and colour contrast sensitivity in patients with normal tension glaucoma.
Luksch, A, Rainer, G, Koyuncu, D, Ehrlich, P, Maca, T, Gschwandtner, ME, Vass, C, Schmetterer, L
The British journal of ophthalmology. 2005;(1):21-5
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AIM: To investigate the effects of oral nimodipine on ocular haemodynamic parameters and colour contrast sensitivity in patients with normal tension glaucoma (NTG). DESIGN The study was performed in a randomised, placebo controlled, double masked, crossover design. PARTICIPANTS Nimodipine (60 mg) or placebo was administered to 14 consecutive NTG patients. METHODS The effects or oral nimodipine or placebo on ocular and systemic haemodynamic parameters and colour contrast sensitivity along the tritan axis were studied two hours after administration. Optic nerve head blood flow (ONHBF) and choroidal blood flow (CHBF) were assessed with laser Doppler flowmetry. Ocular fundus pulsation amplitude (FPA) was measured with laser interferometry. Colour contrast sensitivity (CCS) was determined along the tritan colour axis. MAIN OUTCOME MEASURES ONHBF, CHBF, FPA, intraocular pressure and CCS were assessed in patients with NTG. RESULTS Mean ocular FPA increased by 14% (SD 14%) (p = 0.0008), ONHBF by 18% (SD 16%) (p = 0.0031), and CHBF by 12% (SD 14%) (p<0.001) after administration of nimodipine. Nimodipine also decreased the threshold of colour contrast sensitivity along the tritan colour axis (-14% (SD 12%); p = 0.048). However, individual changes in FPA, ONHBF, or CHBF were not correlated with changes in threshold of CCS along the tritan colour axis. CONCLUSIONS The results indicate that nimodipine increases ONH and choroidal blood flow in NTG patients and improves CCS. The latter effect does not, however, seem to be a direct consequence of the blood flow improvement.