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1.
Inorganic nitrate supplementation attenuates conduit artery retrograde and oscillatory shear in older adults.
Casey, DP, Bock, JM
American journal of physiology. Heart and circulatory physiology. 2021;(3):H991-H998
Abstract
Aging causes deleterious changes in resting conduit artery shear patterns and reduced blood flow during exercise partially attributable to reduced nitric oxide (NO). Inorganic nitrate increases circulating NO bioavailability and may, therefore, improve age-associated changes in shear rate as well as exercise hyperemia. Ten older adults (age: 67 ± 3 yr) consumed 4.03 mmol nitrate and 0.29 mmol nitrite (active) or devoid of both (placebo) daily for 4 wk in a randomized, double-blinded, crossover fashion. Brachial artery diameter (D) and blood velocity (Vmean) were measured via Doppler ultrasound at rest for the characterization of shear profile as well as during two handgrip exercise trials (4 and 8 kg) for calculation of forearm blood flow (Vmean × cross-sectional area, FBF) and conductance [FBF/mean arterial pressure, forearm vascular conductance (FVC)]. Plasma [nitrate] and [nitrite] increased following active (P < 0.05 for both) but not placebo (P = 0.68 and 0.40, respectively) supplementation. Neither mean nor antegrade shear rate changed following either supplement (beverage-by-time P = 0.14 and 0.21, respectively). Retrograde (-13.4 ± 7.0 to -9.7 ± 6.8·s-1) and oscillatory (0.20 ± 0.08 to 0.15 ± 0.09 A.U., P < 0.05 for both) shear decreased following active, but not placebo (P = 0.81 and 0.70, respectively), supplementation. The FBF response (Δ from rest) to neither 4-kg nor 8-kg trials changed following either supplement (beverage-by-time P = 0.53 and 0.11, respectively). Similarly, no changes were observed in FVC responses to 4-kg or 8-kg trials (beverage-by-time P = 0.23 and 0.07, respectively). These data indicate that inorganic nitrate supplementation improves conduit artery shear profiles, but not exercise hyperemia, in older adults.NEW & NOTEWORTHY We report for the first time, to our knowledge, that 4 wk of inorganic nitrate supplementation attenuates retrograde and oscillatory shear in the brachial artery of older adults. However, this was not associated with greater hyperemic or vasodilatory responses to exercise. In sum, these data highlight favorable changes in shear patterns with aging, which may reduce the risk of atherosclerotic cardiovascular disease.
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Renal hemodynamic effects differ between antidiabetic combination strategies: randomized controlled clinical trial comparing empagliflozin/linagliptin with metformin/insulin glargine.
Ott, C, Jung, S, Korn, M, Kannenkeril, D, Bosch, A, Kolwelter, J, Striepe, K, Bramlage, P, Schiffer, M, Schmieder, RE
Cardiovascular diabetology. 2021;(1):178
Abstract
BACKGROUND Type 2 diabetes causes cardio-renal complications and is treated with different combination therapies. The renal hemodynamics profile of such combination therapies has not been evaluated in detail. METHODS Patients (N = 97) with type 2 diabetes were randomized to receive either empagliflozin and linagliptin (E+L group) or metformin and insulin glargine (M+I group) for 3 months. Renal hemodynamics were assessed with para-aminohippuric acid and inulin for renal plasma flow (RPF) and glomerular filtration rate (GFR). Intraglomerular hemodynamics were calculated according the Gomez´ model. RESULTS Treatment with E+L reduced GFR (p = 0.003), but RPF remained unchanged (p = 0.536). In contrast, M+I not only reduced GFR (p = 0.001), but also resulted in a significant reduction of RPF (p < 0.001). Renal vascular resistance (RVR) decreased with E+L treatment (p = 0.001) but increased with M+I treatment (p = 0.001). The changes in RPF and RVR were different between the two groups (both padjust < 0.001). Analysis of intraglomerular hemodynamics revealed that E+L did not change resistance of afferent arteriole (RA) (p = 0.116), but diminished resistance of efferent arterioles (RE) (p = 0.001). In M+I group RA was increased (p = 0.006) and RE remained unchanged (p = 0.538). The effects on RA (padjust < 0.05) and on RE (padjust < 0.05) differed between the groups. CONCLUSIONS In patients with type 2 diabetes and preserved renal function treatment with M+I resulted in reduction of renal perfusion and increase in vascular resistance, in contrast to treatment with E+I that preserved renal perfusion and reduced vascular resistance. Moreover, different underlying effects on the resistance vessels have been estimated according to the Gomez model, with M+I increasing RA and E+L predominantly decreasing RE, which is in contrast to the proposed sodium-glucose cotransporter 2 inhibitor effects. TRIAL REGISTRATION The study was registered at www.clinicaltrials.gov (NCT02752113) on April 26, 2016.
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Intradialytic exercise with blood flow restriction: Something to add to hemodialysis adequacy? Findings from a crossover study.
Dias, EC, Orcy, R, Antunes, MF, Kohn, R, Rombaldi, AJ, Ribeiro, L, Oses, JP, Ferreira, GD, Araújo, AM, Boff, IF, et al
Hemodialysis international. International Symposium on Home Hemodialysis. 2020;(1):71-78
Abstract
INTRODUCTION Hemodialysis (HD) increases the lifespan of chronic kidney disease (CKD) patients. However, HD is only partially effective in replacing renal function. The aim of this study is to compare HD adequacy between sessions with intradialytic exercise with or without blood flow restriction (BFR) with sessions without exercise. METHODS A crossover study including 22 adult CKD patients on HD. The patients were assigned to BFR (n = 11) or exercise alone group (n = 11). Each patient was submitted to four HD sessions (two with exercise and two control sessions). HD adequacy was assessed by equilibrated Kt/V-urea (eKT/V), single-pool Kt/V-urea (sp-Kt/V), urea and phosphorus rebound, urea reduction ratio (URR) and removal of urea and phosphorus in dialysate. FINDINGS BFR exercise improved eKt/V and sp-Kt/V (1.32 ± 0.21 vs. 1.10 ± 0.16 for control, P < 0.001; 1.53 ± 0.26 vs. 1.27 ± 0.19 for control, P < 0.001, respectively) and URR (72.5 ± 5.4% vs. 66.1 ± 7.7% for control, P < 0.001). No difference in eKt/V, sp-Kt/V or URR could be detected between exercise alone and control HD sessions. Urea rebound was lower in BFR exercise vs. control sessions (-8.9 ± 9.1% vs. 30.7 ± 12.8%, P < 0.01) and exercise alone vs. control sessions (13.3 ± 29.0% vs. 42.4 ± 15.3%, P < 0.01). Phosphorus rebound was marginally lower in exercise vs. control sessions (14.4 ± 19.1% vs. 28.4 ± 22.1%, P = 0.18). Urea and phosphorus mass removal in dialysate were marginally higher in exercise vs. control sessions (42.2 ± 19.4 g vs. 35.7 ± 12.5 g, P = 0.24; 912.1 ± 360.9 mg vs. 778.6 ± 245.1 mg, P = 0.28). CONCLUSIONS Intradialytic exercise with BFR was more effective than standard exercise in increasing HD adequacy.
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Omega-3 polyunsaturated fatty acid supplementation versus placebo on vascular health, glycaemic control, and metabolic parameters in people with type 1 diabetes: a randomised controlled preliminary trial.
O'Mahoney, LL, Dunseath, G, Churm, R, Holmes, M, Boesch, C, Stavropoulos-Kalinoglou, A, Ajjan, RA, Birch, KM, Orsi, NM, Mappa, G, et al
Cardiovascular diabetology. 2020;(1):127
Abstract
BACKGROUND The role of omega-3 polyunsaturated fatty acids (n-3PUFA), and the potential impact of n-3PUFA supplementation, in the treatment and management of type 1 diabetes (T1D) remains unclear and controversial. Therefore, this study aimed to examine the efficacy of daily high-dose-bolus n-3PUFA supplementation on vascular health, glycaemic control, and metabolic parameters in subjects with T1D. METHODS Twenty-seven adults with T1D were recruited to a 6-month randomised, double-blind, placebo-controlled trial. Subjects received either 3.3 g/day of encapsulated n-3PUFA or encapsulated 3.0 g/day corn oil placebo (PLA) for 6-months, with follow-up at 9-months after 3-month washout. Erythrocyte fatty acid composition was determined via gas chromatography. Endpoints included inflammation-associated endothelial biomarkers (vascular cell adhesion molecule-1 [VCAM-1], intercellular adhesion molecule-1 [ICAM-1], E-selectin, P-selectin, pentraxin-3, vascular endothelial growth factor [VEGF]), and their mediator tumor necrosis factor alpha [TNFα] analysed via immunoassay, vascular structure (carotid intima-media thickness [CIMT]) and function (brachial artery flow mediated dilation [FMD]) determined via ultrasound technique, blood pressure, glycosylated haemoglobin (HbA1c), fasting plasma glucose (FPG), and postprandial metabolism. RESULTS Twenty subjects completed the trial in full. In the n-3PUFA group, the mean ± SD baseline n-3PUFA index of 4.93 ± 0.94% increased to 7.67 ± 1.86% (P < 0.001) after 3-months, and 8.29 ± 1.45% (P < 0.001) after 6-months. Total exposure to n-3PUFA over the 6-months (area under the curve) was 14.27 ± 3.05% per month under n-3PUFA, and 9.11 ± 2.74% per month under PLA (P < 0.001). VCAM-1, ICAM-1, E-selectin, P-selectin, pentraxin-3, VEGF, TNFα, CIMT, FMD, blood pressure, HbA1c, FPG, and postprandial metabolism did not differ between or within groups after treatment (P > 0.05). CONCLUSIONS This study indicates that daily high-dose-bolus of n-3PUFA supplementation for 6-months does not improve vascular health, glucose homeostasis, or metabolic parameters in subjects with T1D. The findings from this preliminary RCT do not support the use of therapeutic n-3PUFA supplementation in the treatment and management of T1D and its associated complications. Trial Registration ISRCTN, ISRCTN40811115. Registered 27 June 2017, http://www.isrctn.com/ISRCTN40811115 .
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Modulation of simultaneously collected hemodynamic and electrophysiological functional connectivity by ketamine and midazolam.
Forsyth, A, McMillan, R, Campbell, D, Malpas, G, Maxwell, E, Sleigh, J, Dukart, J, Hipp, J, Muthukumaraswamy, SD
Human brain mapping. 2020;(6):1472-1494
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Abstract
The pharmacological modulation of functional connectivity in the brain may underlie therapeutic efficacy for several neurological and psychiatric disorders. Functional magnetic resonance imaging (fMRI) provides a noninvasive method of assessing this modulation, however, the indirect nature of the blood-oxygen level dependent signal restricts the discrimination of neural from physiological contributions. Here we followed two approaches to assess the validity of fMRI functional connectivity in developing drug biomarkers, using simultaneous electroencephalography (EEG)/fMRI in a placebo-controlled, three-way crossover design with ketamine and midazolam. First, we compared seven different preprocessing pipelines to determine their impact on the connectivity of common resting-state networks. Independent components analysis (ICA)-denoising resulted in stronger reductions in connectivity after ketamine, and weaker increases after midazolam, than pipelines employing physiological noise modelling or averaged signals from cerebrospinal fluid or white matter. This suggests that pipeline decisions should reflect a drug's unique noise structure, and if this is unknown then accepting possible signal loss when choosing extensive ICA denoising pipelines could engender more confidence in the remaining results. We then compared the temporal correlation structure of fMRI to that derived from two connectivity metrics of EEG, which provides a direct measure of neural activity. While electrophysiological estimates based on the power envelope were more closely aligned to BOLD signal connectivity than those based on phase consistency, no significant relationship between the change in electrophysiological and hemodynamic correlation structures was found, implying caution should be used when making cross-modal comparisons of pharmacologically-modulated functional connectivity.
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Respiratory and hemodynamic effects of three different sedative regimens for drug induced sleep endoscopy in sleep apnea patients. A prospective randomized study.
Elkalla, RS, El Mourad, MB
Minerva anestesiologica. 2020;(2):132-140
Abstract
BACKGROUND Drug induced sleep endoscopy (DISE) has emerged as a promising tool for customizing the adequate surgical approach to relieve airway obstruction in sleep apnea patients. We aimed to compare propofol, dexmedetomidine or ketofol with regards their efficacy and safety for sedation in patients with obstructive sleep apnea (OSA) undergoing DISE procedure. METHODS Sixty adult OSA patients scheduled for DISE procedure were randomly allocated into three equal groups to receive either propofol (group P), dexmedetomidine (group D), or ketofol (group K). Incidence of oxygen desaturation <90%, hemodynamic variables, time to achieve sufficient sedation level, recovery time, patients' and endoscopists' satisfaction, and incidence of adverse effects were recorded. RESULTS Higher incidence of oxygen desaturation <90% was observed in group P as compared to groups D and K (70%, 35%, and 30% respectively, P=0.021*). Group D showed a significantly longer time to reach target sedation level, prolonged recovery time with more consumption of rescue propofol as compared to group P and group K (P=0.000*, 0.000*, 0.000* respectively). Heart rate values were lower in group D after the loading dose till 30 min postoperative as compared to the other two groups, while blood pressure was lower in both P and D groups at five, 10, 15 min, and on reaching recovery room compared to K group. Two patients in the K group had psychomimetic symptoms with no difference between groups as regards other adverse events or patients' and endoscopist's satisfactions. CONCLUSIONS Dexmedetomidine and ketofol provided a safe respiratory profile compared to propofol during DISE without significant hemodynamic adverse events.
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Metformin use in obese mothers is associated with improved cardiovascular profile in the offspring.
Panagiotopoulou, O, Syngelaki, A, Georgiopoulos, G, Simpson, J, Akolekar, R, Shehata, H, Nicolaides, K, Charakida, M
American journal of obstetrics and gynecology. 2020;(2):246.e1-246.e10
Abstract
BACKGROUND Maternal obesity increases the risk for pregnancy complications and adverse neonatal outcome and has been associated with long-lasting adverse effects in the offspring, including increased body fat mass, insulin resistance, and increased risk for premature cardiovascular disease. Lifestyle interventions in pregnancy have produced no or modest effects in the reduction of adverse pregnancy outcomes in obese mothers. The Metformin in Obese Pregnant Women trial was associated with reduced adverse pregnancy outcomes and had no effect on birthweight. However, the long-term implications of metformin on the health of offspring remain unknown. OBJECTIVE The purpose of this study was to assess whether prenatal exposure to metformin can improve the cardiovascular profile and body composition in the offspring of obese mothers. STUDY DESIGN In 151 children from the Metformin in Obese Pregnant Women trial, body composition, peripheral blood pressure, and arterial pulse wave velocity were measured. Central hemodynamics (central blood pressure and augmentation index) were estimated with the use of an oscillometric device. Left ventricular cardiac function and structure were assessed by echocardiography. RESULTS Children were 3.9±1.0 years old, and 77 of them had been exposed to metformin prenatally. There was no significant difference in peripheral blood pressure, arterial stiffness, and body composition apart from gluteal and tricep circumferences, which were lower in the metformin group (P<.05). The metformin group, compared with the placebo group, had lower central hemodynamics (mean adjusted decrease, -0.707 mm Hg for aortic systolic blood pressure, -1.65 mm Hg for aortic pulse pressure, and -2.68% for augmentation index; P<.05 for all) and lower left ventricular diastolic function (adjusted difference in left atrial area, -0.525 cm2, in isovolumic relaxation time, -0.324 msec, and in pulmonary venous systolic wave, 2.97 cm/s; P<.05 for all). There were no significant differences in metabolic profile between the groups. CONCLUSION Children of obese mothers who were exposed prenatally to metformin, compared with those who were exposed to placebo, had lower central hemodynamic and cardiac diastolic indices. These results suggest that the administration of metformin in obese pregnant women potentially may have a beneficial cardiovascular effect for their offspring.
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A randomized-controlled trial of arginine infusion in severe sepsis on microcirculation and metabolism.
Luiking, YC, Poeze, M, Deutz, NE
Clinical nutrition (Edinburgh, Scotland). 2020;(6):1764-1773
Abstract
BACKGROUND & AIMS Sepsis is hypothesized as an arginine deficient state, with lack of nitric oxide (NO) for adequate microcirculation and local perfusion. This study aimed to investigate if prolonged (72-h) intravenous l-arginine administration in sepsis patients improves microcirculation. Secondly, effects on arginine and protein metabolism, and organ function were studied. METHODS Critically ill patients with a diagnosis of septic shock participated in a long-term (72 h) randomized double-blind placebo-controlled parallel-group study. l-arginine-HCl (1.2 μmol kg-1 min-1; n = 9) or l-alanine (isocaloric control: 2.4 μmol kg-1 min-1; n = 9) was continuously infused. Primary study outcome was microcirculation, assessed as gastric mucosal perfusion by gastric tonometry (Pr-aCO2 gap) and skin perfusion by Laser Doppler flowmetry. Secondary endpoints were whole body (WB) arginine and protein metabolism, organ function and clinical outcomes. We measured global hemodynamics continuously for safety monitoring. Statistical analyses were performed by mixed model for repeated measures with treatment by time interaction as estimate for between-group difference. RESULTS Pr-aCO2 increased only in the l-arginine group (p = 0.006), without a significant between-group difference (p = 0.17). We found no significant differences in skin perfusion parameters. l-arginine infusion resulted in a larger increase of plasma arginine and ornithine concentrations (p < 0.01), WB (endogenous) arginine appearance (p < 0.001), WB NO synthesis (p = 0.027) and WB arginine to urea conversion (p < 0.001) than infusion of l-alanine. We found no effect on global hemodynamics, and protein metabolism by l-arginine infusion. Organ function parameters were unaffected, except for a significant difference between groups in intra-abdominal pressure over time (p = 0.029). CONCLUSIONS Prolonged intravenous l-arginine administration does not improve local perfusion and organ function despite an increase in WB NO synthesis. Administration is safe with regard to global hemodynamics, but the observed increase in Pr-aCO2 and intra-abdominal pressure warrants careful application of l-arginine infusion and further research, especially in the early stage of septic shock.
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Comparison of short-acting versus extended-release nifedipine: Effects on hemodynamics and sympathetic activity in patients with stable coronary artery disease.
Parker, JD, D' Iorio, M, Floras, JS, Toal, CB
Scientific reports. 2020;(1):565
Abstract
We investigated the impact of short-acting and extended release nifedipine on sympathetic activity using radiotracer methodology in patients with stable coronary artery disease in order to more accurately document the response of the sympathetic nervous system to different formulations of this dihydropyridine calcium channel antagonist. Participants were randomized to placebo, short-acting or extended release nifedipine for 7-10 days. On the final day, systemic blood pressure, cardiac filling pressures, cardiac output, plasma norepinephrine (NE) and total body NE spillover were measured at baseline (time 0) and repeated at intervals for 6 hours. There were no differences in baseline measures between groups. Following the morning dose of study medication there were no changes in hemodynamics or sympathetic activity in the placebo group. However, there was a significant fall in blood pressure and a significant increase in total body NE spillover in both nifedipine groups. Importantly, the increase in sympathetic activity in response to short-acting nifedipine began earlier (30 minutes) and was much greater than that observed in the extended release group, which occurred later (270 minutes). These findings confirm that sustained therapy with nifedipine is associated with activation of the sympathetic nervous system which is dependent on the pharmacokinetics of the formulation.
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Effect of amlodipine on blood flow of preovulatory follicle in women with clomiphene resistant polycystic ovaries: a randomized controlled trial.
Torky, HA, Shata, A, Ahmad, AM, Ragab, M, Abo-Louz, A, Hussein, A, Aly, R
Archives of gynecology and obstetrics. 2020;(3):845-850
Abstract
OBJECTIVE To detect whether amlodipine could increase pre-ovulatory follicular blood flow, thus enhancing ovulation and creating a better chance of conception in women with PCOS. METHODS 165 women were screened of which 124 were qualified and women were equally randomized to 62 receiving clomiphene citrate and amlodipine and 62 receiving clomiphene citrate and placebo. The primary outcome was to detect if amlodipine can improve pre-ovulatory follicle blood flow studied by colour and power Doppler Pulsatility index of ovarian arteries, with drug administration. The secondary outcomes were endometrial thickness and clinical pregnancy. RESULTS The mean value of the ovarian arteries Pulsatility Index was significantly lower in the amlodipine group when compared to those of the placebo group (1.36 and 1.82, respectively, with P value 0.002). Mean endometrial thickness, for all women in both groups, on the day of detecting a mature follicle was significantly higher in the amlodipine group compared to the placebo group (8.99 and 7.0, respectively, with P value 0.003), and clinical pregnancy increased from 11% to 37% in the amlodipine group compared to the placebo group. CONCLUSION Amlodipine improves ovarian blood flow and increases the chances of conception. TRIAL REGISTRATION Pan African Clinical Trial Registry (http://www.pactr.org). Trial No: PAC TR201708002485292.