Chronic kidney disease (CKD) patients have greater blood pressure reactivity to acute cardiovascu... more Chronic kidney disease (CKD) patients have greater blood pressure reactivity to acute cardiovascular stressors and a higher prevalence of hypertension; however, limited information is available regarding the potential role of impaired baroreflex control in non-dialysis CKD patients. The baroreflex plays a homeostatic role in beat-to-beat blood pressure (BP) regulation and impaired cardiac baroreflex sensitivity (cBRS) has been associated with increased blood pressure reactivity and cardiovascular events. However, previous studies in CKD have shown mixed results or have been confounded with co-morbid conditions such as hypertension. Therefore, the aim of the present study was to test the hypothesis that baroreflex control of heart rate (HR) is attenuated in patients with CKD compared to hypertensive controls. Additionally, we tested whether cardiovascular risk factors such as age, arterial stiffness, and BMI are associated with cBRS in patients with CKD. In 15 stage III-IV CKD patien...
Increased blood pressure (BP) variability is a powerful predictor of cardiovascular events and en... more Increased blood pressure (BP) variability is a powerful predictor of cardiovascular events and end-organ damage and is associated with sympathetic overactivity. Given the heightened cardiovascular (CV) risk in patients with chronic kidney disease (CKD), we hypothesized that patients with CKD would exhibit augmented resting beat-to-beat BP variability. Additionally, since aerobic exercise training exerts CV protective effects and has been shown to reduce resting sympathetic activity, we hypothesized that twelve weeks of aerobic exercise training would improve resting beat-to-beat BP variability in patients with CKD. In 25 sedentary patients with CKD stages III-IV [19 male/6 female, age: 62 ± 10 yr, 23 Black/2 White, systolic/diastolic BP: 130 ± 12/73 ± 9 mmHg, BMI: 31 ±7 kg/m2] and 15 controls [11 male/4 female, age: 56 ± 11 yr, 13 Black/2 White, systolic/diastolic BP: 129 ± 12/83 ± 8 mmHg, BMI: 29 ± 3 kg/m2], resting beat-to-beat blood pressure (finger photoplethysmography) was cont...
Pre-clinical models suggested that administration of Amiloride at the carotid sinus antagonizes t... more Pre-clinical models suggested that administration of Amiloride at the carotid sinus antagonizes the acid-sensing ion channels (ASICS), an essential component of the mechanoelectrical transducer in the arterial baroreceptors, reducing cardiac baroreflex sensitivity and perturbing the homeostatic beat-to-beat blood pressure (BP) regulation. However, it is still undetermined whether these findings could be translated into humans. Therefore, we determined whether oral administration of Amiloride reduces the spontaneous cardiac baroreflex (cBRS) sensitivity and perturbs BP regulation in humans. Heart rate (HR; electrocardiography) and beat-to-beat BP (finger photoplethysmography) were continuously measured in 5 healthy men (32 ± 6 yrs) during at least 5 min in two different conditions: (1) Control (CTL) and (2) 3 h after of oral administration of Amiloride (AMD – 5 mg + 50 mg of hydrochlorothiazide), a non-selective antagonist of ASICs. Spontaneous cardiac BRS was determined for all sequ...
American Journal of Physiology-Heart and Circulatory Physiology
Chronic kidney disease (CKD) is characterized by pronounced exercise intolerance and exaggerated ... more Chronic kidney disease (CKD) is characterized by pronounced exercise intolerance and exaggerated blood pressure reactivity during exercise. Classic mechanisms of exercise intolerance in CKD have been extensively described previously and include uremic myopathy, chronic inflammation, malnutrition, and anemia. We contend that these classic mechanisms only partially explain the exercise intolerance experienced in CKD and that alterations in cardiovascular and autonomic regulation also play a key contributing role. The purpose of this review is to examine the physiological factors that contribute to neurocirculatory dysregulation during exercise and discuss the adaptations that result from regular exercise training in CKD. Key neurocirculatory mechanisms contributing to exercise intolerance in CKD include augmentation of the exercise pressor reflex, aberrations in neurocirculatory control, and increased neurovascular transduction. In addition, we highlight how some contributing factors ...
Universidade Federal de São Paulo (UNIFESP), Aug 30, 2016
Ischemic preconditioning (IPC; brief cycles of ischemia) induces protection against ischemia-repe... more Ischemic preconditioning (IPC; brief cycles of ischemia) induces protection against ischemia-reperfusion injury, which occurs due to the fact that the IPC mediates changes in the metabolism of skeletal muscles and micro and macro vascular functions. Moreover, it has been demonstrated that IPC can improve aerobic and anaerobic performance. However, the mechanisms related to this improvement remain unclear. For example, the IPC effect on maximal oxygen consumption (V? O2max) has been controversial. In part, this controversy can be attributed to lack of strict criteria to assess the V? O2max, as well as methodological flaws, such as lack or poor control of placebo and nocebo effects. Thus, limitations from previous studies were circumvented to test the effect of IPC on aerobic metabolism parameters[running oxygen cost (ROC), lactate threshold (LL) e V? O2max] and endurance performance (Tlim) in well-trained runners. Eighteen high-level athletes were submitted to three interventions in random order [IPC; false ultrasound session (PL), and control (CT)]. The athletes were informed that both IPC and the PL would improve performance compared to CT. The expected improvement of the subjects(vs. CT) was 83 and 89% for the IPC and PL, respectively. After each intervention, gas exchange, blood lactate concentration ([Lac]) and perceived exertion (RPE) were measured during a maximum incremental test. Ten minutes later, a supramaximal constant test was used to verify the V? O2max. ROC (P = 0.85), V? O2max (P = 0.68) RPE (P = 0.58), [Lac] (P = 0.65) and LL (P = 0.74) were similar among IPC, PL and CT. Time to exhaustion at supramaximal load was longer after IPC (166 ± 13 s) and PL (165 ± 13 s) than CT (143 ± 13 s; P <0.05). In summary, these results indicate that the IPC improved aerobic performance in middle and long distance runners, but the improvement was not greater than placebo. Moreover, IPC did not change LL, ROC and V? O2max.O pré-condicionamento isquêmico (PCI; breves ciclos de isquemia) induz proteção contra a lesão provocada por isquemia-reperfusão, o que ocorre devido ao fato do PCI mediar alterações no metabolismo dos músculos esqueléticos e nas funções micro e macro vascular. Além disso, tem sido demonstrado que o PCI pode efetivamente melhorar o desempenho em exercícios aeróbios e anaeróbios. Entretanto, os mecanismos relacionados a esta melhora são desconhecidos. Por exemplo, o efeito do PCI sobre o consumo máximo de oxigênio (V? O2máx) é controverso. Em parte, esta controvérsia pode ser atribuída a falta de critérios rigorosos para avaliar o V? O2máx, bem como a falhas metodológicas, como ausência ou mau controle dos efeitos placebo e nocebo. Assim, as limitações de estudos anteriores foram contornadas para testar o efeito do PCI em parâmetros determinantes do metabolismo aeróbio [custo de oxigênio para correr (COC), limiar de lactato (LL) e V? O2máx] e desempenho de resistência (Tlim) em corredores bem treinados. Para isso, 18 corredores de alto nível foram randomizados em três intervenções, em ordem aleatória [PCI; sessão de ultrassom falsa (PL); e controle(CT)]. Os atletas foram informados que tanto PCI quanto PL melhorariam o desempenho em comparação com CT. A expectativa de melhora dos sujeitos (vs. CT) foi de 83 e 89% para o PCI e PL, respectivamente. Depois de cada intervenção, as trocas gasosas, lactato sanguíneo [Lac] e percepção subjetiva de esforço (PSE) foram avaliadas durante um teste incremental máximo. Dez minutos depois, um teste de carga constante em intensidade supramáxima foi utilizado para verificar o V? O2máx. COC (P = 0,85), V? O2máx (P = 0,68), PSE (P = 0,58), [Lac] (P = 0,65) e LL (P = 0,74) foram semelhantes entre PCI, PL e CT. Tempo de exaustão na carga supramáxima foi semelhante entre PCI (166 ± 13 s) e PL (165 ± 13 s), e ambos PCI e PL apresentaram tempo mais longo que o CT (143 ± 13 s, P < 0,05). Em resumo, estes resultados indicam que o PCI melhorou o desempenho aeróbio em corredores de meio fundo e fundo, mas a melhora não foi superior ao placebo. Além disso, o PCI não provocou efeito sobre o LL, COC e V? O2máx.Dados abertos - Sucupira - Teses e dissertações (2013 a 2016
Attenuated baroreflex gain may contribute to adverse cardiovascular outcomes, including orthostat... more Attenuated baroreflex gain may contribute to adverse cardiovascular outcomes, including orthostatic intolerance symptoms typically observed in patients with Parkinson's disease. We found that the baroreflex gain (assessed by the modified-Oxford technique) is attenuated and accompanied by an increased operating range in patients with Parkinson's disease. These findings highlight that cardiovascular perturbations are required to detect baroreflex impairments and that spontaneous indices do not reveal cardiovagal-baroreflex dysfunction in a middle-aged group of patients with Parkinson's disease.
Chronic kidney disease (CKD) patients have greater blood pressure reactivity to acute cardiovascu... more Chronic kidney disease (CKD) patients have greater blood pressure reactivity to acute cardiovascular stressors and a higher prevalence of hypertension; however, limited information is available regarding the potential role of impaired baroreflex control in non-dialysis CKD patients. The baroreflex plays a homeostatic role in beat-to-beat blood pressure (BP) regulation and impaired cardiac baroreflex sensitivity (cBRS) has been associated with increased blood pressure reactivity and cardiovascular events. However, previous studies in CKD have shown mixed results or have been confounded with co-morbid conditions such as hypertension. Therefore, the aim of the present study was to test the hypothesis that baroreflex control of heart rate (HR) is attenuated in patients with CKD compared to hypertensive controls. Additionally, we tested whether cardiovascular risk factors such as age, arterial stiffness, and BMI are associated with cBRS in patients with CKD. In 15 stage III-IV CKD patien...
Increased blood pressure (BP) variability is a powerful predictor of cardiovascular events and en... more Increased blood pressure (BP) variability is a powerful predictor of cardiovascular events and end-organ damage and is associated with sympathetic overactivity. Given the heightened cardiovascular (CV) risk in patients with chronic kidney disease (CKD), we hypothesized that patients with CKD would exhibit augmented resting beat-to-beat BP variability. Additionally, since aerobic exercise training exerts CV protective effects and has been shown to reduce resting sympathetic activity, we hypothesized that twelve weeks of aerobic exercise training would improve resting beat-to-beat BP variability in patients with CKD. In 25 sedentary patients with CKD stages III-IV [19 male/6 female, age: 62 ± 10 yr, 23 Black/2 White, systolic/diastolic BP: 130 ± 12/73 ± 9 mmHg, BMI: 31 ±7 kg/m2] and 15 controls [11 male/4 female, age: 56 ± 11 yr, 13 Black/2 White, systolic/diastolic BP: 129 ± 12/83 ± 8 mmHg, BMI: 29 ± 3 kg/m2], resting beat-to-beat blood pressure (finger photoplethysmography) was cont...
Pre-clinical models suggested that administration of Amiloride at the carotid sinus antagonizes t... more Pre-clinical models suggested that administration of Amiloride at the carotid sinus antagonizes the acid-sensing ion channels (ASICS), an essential component of the mechanoelectrical transducer in the arterial baroreceptors, reducing cardiac baroreflex sensitivity and perturbing the homeostatic beat-to-beat blood pressure (BP) regulation. However, it is still undetermined whether these findings could be translated into humans. Therefore, we determined whether oral administration of Amiloride reduces the spontaneous cardiac baroreflex (cBRS) sensitivity and perturbs BP regulation in humans. Heart rate (HR; electrocardiography) and beat-to-beat BP (finger photoplethysmography) were continuously measured in 5 healthy men (32 ± 6 yrs) during at least 5 min in two different conditions: (1) Control (CTL) and (2) 3 h after of oral administration of Amiloride (AMD – 5 mg + 50 mg of hydrochlorothiazide), a non-selective antagonist of ASICs. Spontaneous cardiac BRS was determined for all sequ...
American Journal of Physiology-Heart and Circulatory Physiology
Chronic kidney disease (CKD) is characterized by pronounced exercise intolerance and exaggerated ... more Chronic kidney disease (CKD) is characterized by pronounced exercise intolerance and exaggerated blood pressure reactivity during exercise. Classic mechanisms of exercise intolerance in CKD have been extensively described previously and include uremic myopathy, chronic inflammation, malnutrition, and anemia. We contend that these classic mechanisms only partially explain the exercise intolerance experienced in CKD and that alterations in cardiovascular and autonomic regulation also play a key contributing role. The purpose of this review is to examine the physiological factors that contribute to neurocirculatory dysregulation during exercise and discuss the adaptations that result from regular exercise training in CKD. Key neurocirculatory mechanisms contributing to exercise intolerance in CKD include augmentation of the exercise pressor reflex, aberrations in neurocirculatory control, and increased neurovascular transduction. In addition, we highlight how some contributing factors ...
Universidade Federal de São Paulo (UNIFESP), Aug 30, 2016
Ischemic preconditioning (IPC; brief cycles of ischemia) induces protection against ischemia-repe... more Ischemic preconditioning (IPC; brief cycles of ischemia) induces protection against ischemia-reperfusion injury, which occurs due to the fact that the IPC mediates changes in the metabolism of skeletal muscles and micro and macro vascular functions. Moreover, it has been demonstrated that IPC can improve aerobic and anaerobic performance. However, the mechanisms related to this improvement remain unclear. For example, the IPC effect on maximal oxygen consumption (V? O2max) has been controversial. In part, this controversy can be attributed to lack of strict criteria to assess the V? O2max, as well as methodological flaws, such as lack or poor control of placebo and nocebo effects. Thus, limitations from previous studies were circumvented to test the effect of IPC on aerobic metabolism parameters[running oxygen cost (ROC), lactate threshold (LL) e V? O2max] and endurance performance (Tlim) in well-trained runners. Eighteen high-level athletes were submitted to three interventions in random order [IPC; false ultrasound session (PL), and control (CT)]. The athletes were informed that both IPC and the PL would improve performance compared to CT. The expected improvement of the subjects(vs. CT) was 83 and 89% for the IPC and PL, respectively. After each intervention, gas exchange, blood lactate concentration ([Lac]) and perceived exertion (RPE) were measured during a maximum incremental test. Ten minutes later, a supramaximal constant test was used to verify the V? O2max. ROC (P = 0.85), V? O2max (P = 0.68) RPE (P = 0.58), [Lac] (P = 0.65) and LL (P = 0.74) were similar among IPC, PL and CT. Time to exhaustion at supramaximal load was longer after IPC (166 ± 13 s) and PL (165 ± 13 s) than CT (143 ± 13 s; P <0.05). In summary, these results indicate that the IPC improved aerobic performance in middle and long distance runners, but the improvement was not greater than placebo. Moreover, IPC did not change LL, ROC and V? O2max.O pré-condicionamento isquêmico (PCI; breves ciclos de isquemia) induz proteção contra a lesão provocada por isquemia-reperfusão, o que ocorre devido ao fato do PCI mediar alterações no metabolismo dos músculos esqueléticos e nas funções micro e macro vascular. Além disso, tem sido demonstrado que o PCI pode efetivamente melhorar o desempenho em exercícios aeróbios e anaeróbios. Entretanto, os mecanismos relacionados a esta melhora são desconhecidos. Por exemplo, o efeito do PCI sobre o consumo máximo de oxigênio (V? O2máx) é controverso. Em parte, esta controvérsia pode ser atribuída a falta de critérios rigorosos para avaliar o V? O2máx, bem como a falhas metodológicas, como ausência ou mau controle dos efeitos placebo e nocebo. Assim, as limitações de estudos anteriores foram contornadas para testar o efeito do PCI em parâmetros determinantes do metabolismo aeróbio [custo de oxigênio para correr (COC), limiar de lactato (LL) e V? O2máx] e desempenho de resistência (Tlim) em corredores bem treinados. Para isso, 18 corredores de alto nível foram randomizados em três intervenções, em ordem aleatória [PCI; sessão de ultrassom falsa (PL); e controle(CT)]. Os atletas foram informados que tanto PCI quanto PL melhorariam o desempenho em comparação com CT. A expectativa de melhora dos sujeitos (vs. CT) foi de 83 e 89% para o PCI e PL, respectivamente. Depois de cada intervenção, as trocas gasosas, lactato sanguíneo [Lac] e percepção subjetiva de esforço (PSE) foram avaliadas durante um teste incremental máximo. Dez minutos depois, um teste de carga constante em intensidade supramáxima foi utilizado para verificar o V? O2máx. COC (P = 0,85), V? O2máx (P = 0,68), PSE (P = 0,58), [Lac] (P = 0,65) e LL (P = 0,74) foram semelhantes entre PCI, PL e CT. Tempo de exaustão na carga supramáxima foi semelhante entre PCI (166 ± 13 s) e PL (165 ± 13 s), e ambos PCI e PL apresentaram tempo mais longo que o CT (143 ± 13 s, P < 0,05). Em resumo, estes resultados indicam que o PCI melhorou o desempenho aeróbio em corredores de meio fundo e fundo, mas a melhora não foi superior ao placebo. Além disso, o PCI não provocou efeito sobre o LL, COC e V? O2máx.Dados abertos - Sucupira - Teses e dissertações (2013 a 2016
Attenuated baroreflex gain may contribute to adverse cardiovascular outcomes, including orthostat... more Attenuated baroreflex gain may contribute to adverse cardiovascular outcomes, including orthostatic intolerance symptoms typically observed in patients with Parkinson's disease. We found that the baroreflex gain (assessed by the modified-Oxford technique) is attenuated and accompanied by an increased operating range in patients with Parkinson's disease. These findings highlight that cardiovascular perturbations are required to detect baroreflex impairments and that spontaneous indices do not reveal cardiovagal-baroreflex dysfunction in a middle-aged group of patients with Parkinson's disease.
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