RESUMO
The incidence of cardiovascular diseases in vegetarian individuals is lower than that in the general population. Nevertheless, individuals who adhere to vegan diets have a higher prevalence of hyperhomocysteinemia with eventual adverse effects on vascular reactivity. Creatine supplementation (CrS) reduces plasma homocysteine levels and enhances vascular reactivity in the microcirculation. Thus, we investigated the effects of CrS on systemic microcirculation and homocysteine blood levels in strict vegan subjects. Forty-nine strict vegan subjects were allocated to the oral CrS (5 g micronized creatine monohydrate daily for three weeks; n = 31) and placebo (n = 18) groups. Laser speckle contrast imaging coupled with acetylcholine skin iontophoresis was used to evaluate cutaneous microvascular reactivity, and intravital video-microscopy was used to evaluate skin capillary density and reactivity before and after CrS. We demonstrated that CrS reduces the plasma levels of homocysteine and increases those of folic acid. After the CrS period, the homocysteine levels of all of the vegan subjects normalized. CrS also induced increases in baseline skin functional capillary density and endothelium-dependent capillary recruitment in both normo- (N-Hcy) and hyperhomocysteinemic (H-Hcy) individuals. CrS increased endothelium-dependent skin microvascular vasodilation in the H-Hcy vegan subjects but not in the N-Hcy vegan subjects. In conclusion, three weeks of oral CrS was sufficient to increase skin capillary density and recruitment and endothelium-dependent microvascular reactivity. CrS also resulted in plasma increases in folic acid levels and reductions in homocysteine levels among only the H-Hcy individuals.
Assuntos
Creatina/farmacologia , Creatina/uso terapêutico , Dieta Vegana , Endotélio Vascular/efeitos dos fármacos , Hiper-Homocisteinemia/tratamento farmacológico , Adulto , Pesos e Medidas Corporais , Creatina/administração & dosagem , Suplementos Nutricionais , Feminino , Ácido Fólico , Humanos , Iontoforese , Fluxometria por Laser-Doppler , Masculino , Pessoa de Meia-Idade , Fluxo Sanguíneo Regional/efeitos dos fármacosRESUMO
INTRODUCTION: Physical inactivity and increased caloric intake play important roles in the pathophysiology of obesity. Increasing physical activity and modifying eating behaviours are first-line interventions, frequently hampered by lack of time to exercise and difficulties in coping with different diets. High-intensity interval training (HIIT) may be a time-efficient method compared with moderate-intensity continuous training (CT). Conversely, diets with a fasting component may be more effective than other complex and restrictive diets, as it essentially limits caloric intake to a specified period without major diet composition changes. Therefore, the combination of HIIT and fasting may provide incremental benefits in terms of effectiveness and time efficiency in obese and sedentary populations. The aim of this study is to determine the effect of HIIT versus CT, combined or not with fasting, on microcirculatory function, cardiometabolic parameters, anthropometric indices, cardiorespiratory fitness and quality of life in a population of sedentary overweight or obese women with cardiometabolic risk factors. METHODS AND ANALYSIS: Sedentary women aged 30-50 years, with a body mass index ≥25 kg/m2 and cardiometabolic risk factors, will be randomised to HIIT performed in the fasting state, HIIT performed in the fed state, CT in the fasting state or CT in the fed state. Cardiometabolic parameters, anthropometric indices, cardiorespiratory fitness, quality of life and microvascular function (cutaneous capillary density and microvascular reactivity evaluated by laser speckle contrast imaging) will be evaluated before initiation of the interventions and 16 weeks thereafter. ETHICS AND DISSEMINATION: The trial complies with the Declaration of Helsinki and has been approved by the local ethics committee (Instituto Nacional de Cardiologia, Rio de Janeiro, Brazil). All patients provide written informed consent before enrolment and randomisation. The study's results will be disseminated to the healthcare community by publications and presentations at scientific meetings. TRIAL REGISTRATION NUMBER: NCT03236285.
Assuntos
Doenças Cardiovasculares , Treinamento Intervalado de Alta Intensidade , Microcirculação , Sobrepeso , Adulto , Brasil , Doenças Cardiovasculares/prevenção & controle , Jejum , Feminino , Humanos , Pessoa de Meia-Idade , Obesidade/terapia , Sobrepeso/terapia , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de RiscoRESUMO
Introduction: The main aim of the present study is to evaluate the effects of strenuous exercise, related to special military training for riot control, on systemic microvascular endothelial function and skin capillary density. Materials and Methods: Endothelium-dependent microvascular reactivity was evaluated in the forearm skin of healthy military trainees (age 23.4 ± 2.3 yr; n = 15) using laser speckle contrast imaging coupled with cutaneous acetylcholine (ACh) iontophoresis and post-occlusive reactive hyperemia (PORH). Functional capillary density was assessed using high-resolution, intra-vital color microscopy in the dorsum of the middle phalanx. Capillary recruitment (capillary reserve) was evaluated using PORH. Microcirculatory tests were performed before and after a 5-wk special military training for riot control. Results: Microvascular endothelium-dependent vasodilatory responses were markedly and significantly reduced after training, compared with values obtained before training. The peak values of microvascular conductance obtained during iontophoresis of ACh or PORH before training (0.84 ± 0.22 and 0.94 ± 0.72 APU/mmHg, respectively) were markedly reduced after training (0.47 ± 0.11 and 0.71 ± 0.14 APU/mmHg; p < 0.0001 and p = 0.0037, respectively). Endothelium-dependent capillary recruitment was significantly reduced after training (before 101 ± 9 and after 95 ± 8 capillaries/mm2; p = 0.0007). Conclusions: The present study showed that a 5-wk strenuous military training, performed in unfavorable climatic conditions, induces marked systemic microvascular dysfunction, mainly characterized by reduced endothelium-dependent microvascular vasodilation and blunted capillary recruitment.
Assuntos
Endotélio Vascular/fisiologia , Exercício Físico/fisiologia , Microvasos/fisiologia , Tumultos , Ensino/normas , Adulto , Análise de Variância , Brasil , Ação Capilar , Feminino , Antebraço/irrigação sanguínea , Antebraço/fisiologia , Humanos , Iontoforese/métodos , Masculino , Ensino/estatística & dados numéricosRESUMO
BACKGROUND: The aim of the present study was to evaluate changes in microvascular density and reactivity in patients with type 1 diabetes (T1D) resulting from low intensity chronic exercise training. METHODS: This study included 22 (34 ± 7 ears) consecutive outpatients with T1D and disease duration > 6 years. We used intravital video-microscopy to measure basal skin capillary density and capillary recruitment using post-occlusive reactive hyperemia (PORH) in the dorsum of the fingers. Endothelium-dependent and -independent vasodilation of the skin microcirculation was evaluated in the forearm with a laser Doppler flow monitoring (LDF) system in combination with acetylcholine and sodium nitroprusside iontophoresis, PORH and local thermal hyperemia. RESULTS: The basal mean capillary density (MCD) after exercise training was significantly higher than before exercise (134 ± 25 vs. 119 ± 19 capillaries/mm(2), respectively; P = 0.0013). MCD during PORH was also higher after exercise (140 ± 26 vs. 121 ± 24 capillaries/mm(2), respectively; P < 0.0001). Endothelium-dependent capillary recruitment during PORH was also significantly higher after exercise (140 ± 26 vs. 134 ± 25 capillaries/mm(2), respectively; P < 0.0012). There were no significant changes in skin microvascular reactivity after exercise as investigated using LDF. CONCLUSIONS: Our results showed that low intensity aerobic exercise, performed four times per week for 12 weeks by patients with T1D, induces significant increases in microvascular density and endothelial-dependent capillary reactivity. TRIAL REGISTRATION: ClinicalTrials.gov NCT02441504. Registered 7 May 2015.