RESUMO
Patients with type 2 diabetes mellitus (T2DM) have reduced exercise capacity, indexed by lower maximal oxygen consumption (VÌo2max) and achievement of the gas exchange threshold (GET) at a lower % VÌo2max. The ubiquitous signaling molecule nitric oxide (NO) plays a multifaceted role during exercise and, as patients with T2DM have poor endogenous NO production, we investigated if inorganic nitrate/nitrite supplementation (an exogenous source of NO) improves exercise capacity in patients with T2DM. Thirty-six patients with T2DM (10F, 59 ± 9 yr, 32.0 ± 5.1 kg/m2, HbA1c = 7.4 ± 1.4%) consumed beetroot juice containing either inorganic nitrate/nitrite (4.03 mmol/0.29 mmol) or a placebo (0.8 mmol/0.00 mmol) for 8 wk. A maximal exercise test was completed before and after both interventions. VÌo2max was determined by averaging 15-s data, whereas the GET was identified using the V-slope method and breath-by-breath data. Inorganic nitrate/nitrite increased both absolute (1.96 ± 0.67 to 2.07 ± 0.75 L/min) and relative (20.7 ± 7.0 to 21.9 ± 7.4 mL/kg/min, P < 0.05 for both) VÌo2max, whereas no changes were observed following placebo (1.94 ± 0.40 to 1.90 ± 0.39 L/min, P = 0.33; 20.0 ± 4.2 to 19.7 ± 4.6 mL/kg/min, P = 0.39). Maximal workload was also increased following inorganic nitrate/nitrite supplementation (134 ± 47 to 140 ± 51 W, P < 0.05) but not placebo (138 ± 32 to 138 ± 32 W, P = 0.98). VÌo2 at the GET (1.11 ± 0.27 to 1.27 ± 0.38L/min) and the %VÌo2max in which GET occurred (56 ± 8 to 61 ± 7%, P < 0.05 for both) increased following inorganic nitrate/nitrite supplementation but not placebo (1.10 ± 0.23 to 1.08 ± 0.21 L/min, P = 0.60; 57 ± 9 to 57 ± 8%, P = 0.90) although the workload at GET did not achieve statistical significance (group-by-time P = 0.06). Combined inorganic nitrate/nitrite consumption improves exercise capacity, maximal workload, and promotes a rightward shift in the GET in patients with T2DM. This manuscript reports data from a registered Clinical Trial at ClinicalTrials.gov ID: NCT02804932.NEW & NOTEWORTHY We report that increasing nitric oxide bioavailability via 8 wk of inorganic nitrate/nitrite supplementation improves maximal aerobic exercise capacity in patients with type 2 diabetes mellitus. Similarly, we observed a rightward shift in the gas exchange threshold. Taken together, these data indicate inorganic nitrate/nitrite may serve as a means to improve fitness in patients with type 2 diabetes mellitus.
Assuntos
Beta vulgaris , Diabetes Mellitus Tipo 2 , Humanos , Tolerância ao Exercício , Nitratos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Óxido Nítrico , Suplementos Nutricionais , Estudos Cross-Over , Método Duplo-Cego , Consumo de OxigênioRESUMO
Nitric oxide (NO) stimulates mitochondrial biogenesis in skeletal muscle. However, NO metabolism is disrupted in individuals with type 2 diabetes mellitus (T2DM) potentially contributing to their decreased cardiorespiratory fitness (i.e., VO2max) and skeletal muscle oxidative capacity. We used a randomized, double-blind, placebo-controlled, 8-week trial with beetroot juice containing nitrate (NO3−) and nitrite (NO2−) (250 mg and 20 mg/day) to test potential benefits on VO2max and skeletal muscle oxidative capacity in T2DM. T2DM (N = 36, Age = 59 ± 9 years; BMI = 31.9 ± 5.0 kg/m2) and age- and BMI-matched non-diabetic controls (N = 15, Age = 60 ± 9 years; BMI = 29.5 ± 4.6 kg/m2) were studied. Mitochondrial respiratory capacity was assessed in muscle biopsies from a subgroup of T2DM and controls (N = 19 and N = 10, respectively). At baseline, T2DM had higher plasma NO3− (100%; p < 0.001) and lower plasma NO2− levels (−46.8%; p < 0.0001) than controls. VO2max was lower in T2DM (−26.4%; p < 0.001), as was maximal carbohydrate- and fatty acid-supported oxygen consumption in permeabilized muscle fibers (−26.1% and −25.5%, respectively; p < 0.05). NO3−/NO2− supplementation increased VO2max (5.3%; p < 0.01). Further, circulating NO2−, but not NO3−, positively correlated with VO2max after supplementation (R2= 0.40; p < 0.05). Within the NO3−/NO2− group, 42% of subjects presented improvements in both carbohydrate- and fatty acid-supported oxygen consumption in skeletal muscle (vs. 0% in placebo; p < 0.05). VO2max improvements in these individuals tended to be larger than in the rest of the NO3−/NO2− group (1.21 ± 0.51 mL/(kg*min) vs. 0.31 ± 0.10 mL/(kg*min); p = 0.09). NO3−/NO2− supplementation increases VO2max in T2DM individuals and improvements in skeletal muscle oxidative capacity appear to occur in those with more pronounced increases in VO2max.
Assuntos
Beta vulgaris , Aptidão Cardiorrespiratória , Diabetes Mellitus Tipo 2 , Humanos , Pessoa de Meia-Idade , Idoso , Nitritos , Nitratos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Dióxido de Nitrogênio/metabolismo , Dióxido de Nitrogênio/farmacologia , Projetos Piloto , Músculo Esquelético/metabolismo , Óxidos de Nitrogênio/metabolismo , Óxido Nítrico/metabolismo , Método Duplo-Cego , Suplementos Nutricionais , Ácidos Graxos/metabolismo , Carboidratos/farmacologia , Estresse OxidativoRESUMO
BACKGROUND: Patients with type 2 diabetes mellitus (T2DM) have increased cardiovascular risk due to elevated blood pressure (BP). As low levels of nitric oxide (NO) may contribute to increased BP, we determined if increasing NO bioavailability via eight weeks of supplementation with beetroot juice containing inorganic nitrate/nitrite (4.03 mmol nitrate, 0.29 mmol nitrite) improves peripheral and central BP relative to nitrate/nitrite-depleted beetroot juice. METHODS: Peripheral and central BP were assessed at heart-level in supine subjects using a brachial artery catheter and applanation tonometry, respectively. RESULTS: Nitrate/nitrite supplementation reduced peripheral systolic BP (148 ± 16 to 142 ± 18 mm Hg, P < 0.05) but not placebo (150 ± 19 to 149 ± 17 mm Hg, P = 0.93); however, diastolic BP was unaffected (supplement-by-time P = 0.08). Central systolic BP (131 ± 16 to 127 ± 17 mm Hg) and augmented pressure (13.3 ± 6.6 to 11.6 ± 6.9 mm Hg, both P < 0.05) were reduced after nitrate/nitrite, but not placebo (134 ± 17 to 135 ± 16 mm Hg, P = 0.62; 14.1 ± 6.6 to 15.2 ± 7.4 mm Hg, P = 0.20); central diastolic BP was unchanged by the interventions (supplement-by-time P = 0.16). Inorganic nitrate/nitrite also reduced AIx (24.3 ± 9.9% to 21.0 ± 9.6%) whereas no changes were observed following placebo (24.6 ± 9.3% to 25.6 ± 9.9%, P = 0.46). CONCLUSIONS: Inorganic nitrate/nitrite supplementation improves peripheral and central BP as well as AIx in T2DM. CLINICAL TRIALS REGISTRATION: Trial Number NCT02804932.
Assuntos
Beta vulgaris , Diabetes Mellitus Tipo 2 , Pressão Sanguínea , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Suplementos Nutricionais , Método Duplo-Cego , Humanos , Nitratos , Óxido Nítrico , NitritosRESUMO
BACKGROUND & AIMS: Peripheral artery disease (PAD) is characterized by elevated blood pressure (BP), low nitric oxide availability (NO), and exaggerated pressor responses to sympatho-excitatory stressors. Inorganic nitrate reduces peripheral BP in healthy and chronically diseased populations. The objective of this study was to investigate the effects of eight-weeks of sodium nitrate (NaNO3) supplementation on indices of BP in PAD patients. METHODS: 21 patients with PAD were recruited to participate in this study, undergoing 8-weeks of NaNO3 (n = 13; 73 ± 9 years) or placebo (n = 8; 69 ± 10 years) supplementation. BP responsiveness to a cold pressor test (CPT) were examined prior to and following the supplementation period. The systolic BP response (change from rest) during the first (26 ± 10 vs. 19 ± 11 mmHg) and second minutes (32 ± 10 vs. 26 ± 12 mmHg) of CPT were reduced following NaNO3 (P < 0.05 for both) but not after placebo (first minute: 22 ± 10 vs. 24 ± 10 mmHg, P = 0.30; second minute 26 ± 10 vs 27 ± 10 mmHg, P = 0.72) supplementation. CONCLUSION: Our data suggest that eight-weeks of NaNO3 supplementation reduces BP responsiveness to sympatho-excitatory stimuli. CLINICAL TRIALS REGISTRATION NUMBER: NCT01983826.
Assuntos
Nitratos , Doença Arterial Periférica , Pressão Sanguínea , Suplementos Nutricionais , Humanos , Doença Arterial Periférica/diagnóstico , Doença Arterial Periférica/tratamento farmacológicoRESUMO
AIMS: Patients with type 2 diabetes mellitus (T2DM) have reduced vasodilatory responses during exercise partially attributable to low nitric oxide (NO) levels. Low NO contributes to greater α-adrenergic mediated vasoconstriction in contracting skeletal muscle. We hypothesized boosting NO bioavailability via 8wks of active beetroot juice (BRA, 4.03 mmol nitrate, 0.29 mmol nitrite, n = 19) improves hyperemia, via reduced α-mediated vasoconstriction, during handgrip exercise relative to nitrate/nitrite-depleted beetroot juice (BRP, n = 18) in patients with T2DM. METHODS: Forearm blood flow (FBF) and vascular conductance (FVC) were calculated at rest and during handgrip exercise (20%max, 20contractions·min-1). Phenylephrine (α1-agonist) and dexmedetomidine (α2-agonist) were infused intra-arterially during independent trials to determine the influence of α-mediated vasoconstriction on exercise hyperemia. Vasoconstriction was quantified as the percent-reduction in FVC during α-agonist infusion, relative to pre-infusion, as well as the absolute change in %FVC during exercise relative to the respective rest trial (magnitude of sympatholysis). RESULTS: ΔFBF (156 ± 69 to 175 ± 73 ml min-1) and ΔFVC (130 ± 54 to 156 ± 63 ml min-1·100 mmHg-1, both P < 0.05) during exercise were augmented following BRA, but not BRP (P = 0.96 and 0.51). Phenylephrine-induced vasoconstriction during exercise was blunted following BRA (-17.1 ± 5.9 to -12.6 ± 3.1%, P < 0.01), but not BRP (P = 0.58) supplementation; the magnitude of sympatholysis was unchanged by either (beverage-by-time P = 0.15). BRA supplementation reduced dexmedetomidine-induced vasoconstriction during exercise (-23.3 ± 6.7 to -19.7 ± 5.2%) and improved the corresponding magnitude of sympatholysis (25.3 ± 11.4 to 34.4 ± 15.5%, both P < 0.05). CONCLUSIONS: BRA supplementation improves the hyperemic and vasodilatory responses to exercise in patients with T2DM which appears to be attributable to reduced α-adrenergic mediated vasoconstriction in contracting skeletal muscle.
Assuntos
Diabetes Mellitus Tipo 2/fisiopatologia , Exercício Físico/fisiologia , Nitratos/farmacologia , Nitritos/farmacologia , Vasoconstrição/efeitos dos fármacos , Agonistas de Receptores Adrenérgicos alfa 1/farmacologia , Idoso , Beta vulgaris/química , Dexmedetomidina/farmacologia , Suplementos Nutricionais , Feminino , Sucos de Frutas e Vegetais , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/efeitos dos fármacos , Óxido Nítrico/metabolismo , Fenilefrina/farmacologia , Raízes de Plantas/químicaRESUMO
Peripheral artery disease (PAD) is characterized by functional and vascular impairments as well as elevated levels of inflammation which are associated with reduced nitric oxide (NO) bioavailability. Inorganic nitrate supplementation boosts NO bioavailability potentially improving functional and vasodilatory capacities and may reduce inflammation. Twenty-one patients with PAD were randomly assigned to sodium nitrate (NaNO3) or placebo supplementation groups for eight-weeks. Outcome measures included a 6-min walk test (6â¯MWT), blood flow and vasodilator function in the forearm and calf, as well as plasma inflammatory and adhesion biomarker concentrations. NaNO3 elevated plasma nitrate (32.3⯱â¯20.0 to 379.8⯱â¯204.6⯵M) and nitrite (192.2⯱â¯51.8 to 353.1⯱â¯134.2â¯nM), improved 6â¯MWT performance (387⯱â¯90 to 425⯱â¯82â¯m), peak calf blood flow (BFPeak; 11.6⯱â¯4.9 to 14.1⯱â¯5.1â¯mL/dLâ¯tissue/min), and peak calf vascular conductance (VCPeak; 11.1⯱â¯4.3 to 14.2⯱â¯4.9â¯mL/dLâ¯tissue/min/mmHg) (pâ¯<â¯0.05 for all). Improvements in calf BFPeak (râ¯=â¯0.70, pâ¯<â¯0.05) and VCPeak (râ¯=â¯0.61, pâ¯<â¯0.05) correlated with changes in 6â¯MWT distance. Placebo supplementation did not change plasma nitrate or nitrite, 6â¯MWT, calf BFPeak, or calf VCPeak. Forearm vascular function nor inflammatory and adhesion biomarker concentrations changed in either group. Eight-weeks of NaNO3 supplementation improves vasodilatory capacity in the lower-limbs of patients with PAD, which correlated with improvement in functional capacity.
Assuntos
Nitratos/administração & dosagem , Doença Arterial Periférica/dietoterapia , Doença Arterial Periférica/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Suplementos Nutricionais , Feminino , Antebraço/irrigação sanguínea , Humanos , Inflamação/sangue , Inflamação/dietoterapia , Masculino , Pessoa de Meia-Idade , Nitratos/efeitos adversos , Nitratos/sangue , Nitritos/sangue , Pletismografia , Fluxo Sanguíneo Regional/efeitos dos fármacos , Vasodilatação/efeitos dos fármacosRESUMO
The vasoactive molecule nitric oxide (NO) contributes to regulation of blood pressure (BP) at rest and during exercise. Age-related exaggerated increased BP responses during exercise have been proposed to be due in part to a decreased NO bioavailability and possibly an enhanced skeletal muscle metaboreflex. In the present study we sought to determine if age-related differences in BP responses to skeletal muscle metaboreflex activation exist. Additionally, since NO bioavailability can be improved with exogenous nitrate (NO3-) via the nitrate-nitrite-NO pathway, we tested the hypothesis that inorganic NO3- supplementation would reduce BP responses to muscle metaboreflex activation in healthy older adults. 13 older adults (67⯱â¯1 years) participated in a randomized, double-blind, placebo controlled crossover study consisting of four weeks of NO3- supplementation [beetroot powder; 250â¯mg (â¼4.03â¯mmol) of NO3- and 20â¯mg (â¼0.29â¯mmol) of NO2-] and four weeks of placebo (beetroot powder devoid of NO3-/NO2-). Skeletal muscle metaboreflex testing consisted of isometric handgrip exercise (IHG) at 30% of maximal voluntary contraction immediately followed by post exercise forearm ischemia (PEI), which was achieved by inflation of a rapid pressure cuff (240â¯mmHg) around the upper arm. BP responses were analyzed as the change (Δ) from baseline to the end of IHG and PEI. An additional 10 young adults (25⯱â¯1 years) were recruited to serve as a reference cohort and address if BP responses to skeletal muscle metaboreflex activation were greater with aging. BP responses to IHG were similar between the young and older adults. However, older adults demonstrated a greater increase in systolic BP during PEI (Pâ¯<â¯0.05). Plasma NO3- and NO2-were increased following NO3- supplementation in older adults (Pâ¯<â¯0.01). ΔSystolic BP (19⯱â¯2 vs. 13±3â¯mmHg, Pâ¯<â¯0.05), ΔDiastolic BP (7⯱â¯1 vs. 5±1â¯mmHg, Pâ¯<â¯0.05) and ΔMean arterial pressure (11⯱â¯1 vs. 8±2â¯mmHg, Pâ¯<â¯0.05) were reduced during PEI following four weeks of NO3-supplementation, whereas placebo had no effect on ΔSystolic BP (16⯱â¯2 vs. 17±2â¯mmHg), ΔDiastolic BP (5⯱â¯1 vs. 7±1â¯mmHg), and ΔMean arterial pressure (8⯱â¯1 vs. 10±1â¯mmHg) during PEI (all Pâ¯>â¯0.05). These data suggest that inorganic NO3- supplementation attenuates skeletal muscle metaboreflex mediated increases in BP during exercise in older adults.
Assuntos
Pressão Sanguínea/efeitos dos fármacos , Músculo Esquelético/metabolismo , Nitratos/administração & dosagem , Extratos Vegetais/administração & dosagem , Administração Oral , Adulto , Idoso , Beta vulgaris/química , Pressão Sanguínea/fisiologia , Estudos Cross-Over , Método Duplo-Cego , Feminino , Força da Mão/fisiologia , Humanos , Masculino , Nitratos/sangue , Nitritos/administração & dosagem , Nitritos/sangue , Raízes de Plantas/química , Reflexo , Adulto JovemRESUMO
Aging is associated with increased peripheral chemoreceptor activity, reduced nitric oxide (NO) bioavailability, and attenuation of cardiovagal baroreflex sensitivity (BRS), collectively increasing the risk of cardiovascular disease. Evidence suggests that NO may attenuate peripheral chemoreflex sensitivity and increase BRS. Exogenous inorganic nitrate ([Formula: see text]) increases NO bioavailability via the [Formula: see text]-[Formula: see text]-NO pathway. Our hypothesis was that inorganic [Formula: see text] supplementation would attenuate peripheral chemoreflex sensitivity and enhance spontaneous cardiovagal BRS in older adults. We used a randomized, placebo-controlled crossover design in which 13 older (67 ± 3 yr old) adults ingested beetroot powder containing (BRA) or devoid of (BRP) [Formula: see text] and [Formula: see text] daily over 4 wk. Spontaneous cardiovagal BRS was assessed over 15 min of rest and was quantified using the sequence method. Chemoreflex sensitivity was assessed via ~5 min of hypoxia (10% fraction of inspired O2) and reported as the slope of the relationship between O2 saturation (%[Formula: see text]) and minute ventilation (in l/min) or heart rate (in beats/min). Ventilatory responsiveness to hypoxia was reduced after BRA (from -0.14 ± 0.04 to -0.05 ± 0.02 l·min-1·%[Formula: see text]-1, P = 0.01) versus BRP (from -0.10 ± 0.05 to -0.11 ± 0.05 l·min-1·%[Formula: see text]-1, P = 0.80), with no differences in heart rate responsiveness (BRA: from -0.47 ± 0.06 to -0.33 ± 0.04 beats·min-1·%[Formula: see text]-1, BRP: from -0.48 ± 0.07 to -0.42 ± 0.06 beats·min-1·%[Formula: see text]-1) between conditions (interaction effect, P = 0.41). Spontaneous cardiovagal BRS was unchanged after BRA and BRP (interaction effects, P = 0.69, 0.94, and 0.39 for all, up, and down sequences, respectively), despite a reduction in resting systolic and mean arterial blood pressure in the experimental (BRA) group ( P < 0.01 for both). These findings illustrate that inorganic [Formula: see text] supplementation attenuates peripheral chemoreflex sensitivity without concomitant change in spontaneous cardiovagal BRS in older adults. NEW & NOTEWORTHY Exogenous inorganic nitrate supplementation attenuates ventilatory, but not heart rate, responsiveness to abbreviated hypoxic exposure in older adults. Additionally, inorganic nitrate reduces systolic and mean arterial blood pressure without affecting spontaneous cardiovagal baroreflex sensitivity. These findings suggest that inorganic nitrate may attenuate sympathetically oriented pathologies associated with aging.
Assuntos
Barorreflexo , Células Quimiorreceptoras/metabolismo , Suplementos Nutricionais , Coração/inervação , Hipóxia/metabolismo , Hipóxia/fisiopatologia , Pulmão/inervação , Nitratos/administração & dosagem , Extratos Vegetais/administração & dosagem , Ventilação Pulmonar , Nervo Vago/fisiopatologia , Fatores Etários , Idoso , Envelhecimento/metabolismo , Pressão Arterial , Beta vulgaris , Estudos Cross-Over , Suplementos Nutricionais/efeitos adversos , Feminino , Sucos de Frutas e Vegetais , Frequência Cardíaca , Humanos , Iowa , Masculino , Pessoa de Meia-Idade , Nitratos/efeitos adversos , Nitratos/isolamento & purificação , Óxido Nítrico/metabolismo , Extratos Vegetais/efeitos adversos , Extratos Vegetais/isolamento & purificação , Raízes de Plantas , Fatores de Tempo , Resultado do TratamentoRESUMO
PURPOSE: Aging is associated with elevated blood pressure (peripheral and aortic; BP) and aortic augmentation index (AIx) which may contribute to aortic BP. Although inorganic nitrate consumption reduces peripheral BP in both young and older adults, the effects of nitrate consumption on aortic BP and wave reflection in young and older adults is unknown. Therefore, we sought to characterize the effects of nitrate consumption on aortic BP and AIx in young and older adults. METHODS: Noninvasive aortic pressure waveforms were synthesized from high-fidelity radial pressure waveforms via applanation tonometry before and following (60, 90, 120, 150, and 180 min) consumption of a nitrate-rich beetroot juice in 26 healthy adults (young: 25 ± 4 years, n = 14; older: 64 ± 5 years, n = 12). Aortic BP and indices of aortic wave reflection (AIx and AIx normalized for heart rate; AIx@75bpm) were calculated from the generated aortic pressure waveform. RESULTS: Nitrate consumption increased plasma nitrite in both groups 60-180 min following beetroot consumption (P < 0.001). Nitrate consumption reduced peripheral and aortic BP in both young and older adults (P < 0.05), with the change being similar between age groups. Conversely, indices of aortic wave reflection were reduced only in young adults following nitrate consumption (range of change from baseline over time: AIx@75bpm, -4.3 to -8.8%, P < 0.05), whereas aortic AIx remained unchanged in the older adults. CONCLUSIONS: Taken together, our results suggest that acute dietary nitrate supplementation reduces peripheral and aortic BP similarly in young and older adults despite differential effects on aortic AIx between age groups.
Assuntos
Pressão Arterial , Beta vulgaris , Suplementos Nutricionais , Sucos de Frutas e Vegetais , Nitratos/administração & dosagem , Adulto , Idoso , Aorta/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Nitritos/sangue , Análise de Onda de Pulso , Rigidez Vascular , Adulto JovemRESUMO
We have previously demonstrated that aging reduces the compensatory vasodilator response during hypoxic exercise due to blunted nitric oxide (NO) signaling. Recent evidence suggests that NO bioavailability can be augmented by dietary nitrate through the nitrate-nitrite pathway. Thus we tested the hypothesis that acute dietary nitrate supplementation increases the compensatory vasodilator response to hypoxic exercise, particularly in older adults. Thirteen young (25 ± 1 yr) and 12 older (64 ± 2 yr) adults performed rhythmic forearm exercise at 20% of maximum voluntary contraction during normoxia and hypoxia (â¼80% O2 saturation); both before (control) and 3 h after beetroot juice (BR) consumption. Forearm vascular conductance (FVC; ml·min(-1)·100 mmHg(-1)) was calculated from forearm blood flow (ml/min) and blood pressure (mmHg). Compensatory vasodilation was defined as the relative increase in FVC due to hypoxic exercise (i.e., % increase compared with respective normoxic exercise trial). Plasma nitrite was determined from venous blood samples obtained before the control trials and each of the exercise trials (normoxia and hypoxia) after BR. Consumption of BR increased plasma nitrite in both young and older adults (P < 0.001). During the control condition, the compensatory vasodilator response to hypoxic exercise was attenuated in older compared with young adults (3.8 ± 1.7% vs. 14.2 ± 1.2%, P < 0.001). Following BR consumption, compensatory vasodilation did not change in young (13.7 ± 3.3%, P = 0.81) adults but was substantially augmented in older adults (11.4 ± 2.1%, P < 0.01). Our data suggest that acute dietary nitrate supplementation increases the compensatory vasodilator response to hypoxic exercise in older but not young adults.
Assuntos
Beta vulgaris , Exercício Físico , Hipóxia/tratamento farmacológico , Nitratos/farmacologia , Vasodilatação/efeitos dos fármacos , Adulto , Fatores Etários , Idoso , Envelhecimento/efeitos dos fármacos , Suplementos Nutricionais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/irrigação sanguínea , Nitratos/sangue , Nitratos/uso terapêutico , Fitoterapia , Extratos Vegetais , Adulto JovemRESUMO
Reduction ascending aortoplasty has been advocated as a possible alternative to traditional graft replacement for treatment of aneurysms of the ascending aorta and root. We report a case of a 58-year-old Jehovah's Witness female, with a 5.5-cm ascending aortic aneurysm and critical aortic stenosis. She underwent aortic valve replacement and reduction aortoplasty buttressed with a Dacron graft. We reviewed the history and contemporary applications of this technique and concluded that aortic reduction with externally supported aortoplasty may represent a viable option to treat Jehovah's Witness patients with ascending aorta and root aneurysm.