ABSTRACT
BACKGROUND AND OBJECTIVE: Obesity is a common feature of resistant arterial hypertension (RHTN) and it is considered a strong risk factor for the lack of blood pressure control. Moreover, increased aldosterone levels have been associated with impaired glucose metabolism and may interact with adipose tissue deregulating inflammatory adipokines such as leptin. This study aimed to verify the influence of obesity in aldosterone and leptin plasma levels as well as in markers ofglucose metabolism in RHTN subjects. METHODS: Ninetyone resistant hypertensive patients were divided into two subgroups by the mean body mass index (BMI): (i) a more obese (OBS, N=41, BMI>31.5kg/m2) and (ii) a leaner group (LNR,N=50, BMI<31.5kg/m2). We determined body composition by bioimpedance (BIA 450). Fasting glucose, glycated hemoglobin (HbA1c) as well as aldosterone (radioimmunoassay) and leptin (enzyme immunoassay) levels were also evaluated. RESULTS: OBS subgroup showed altered glucose metabolism by fasting glucose (129±48 vs. 107±32mg/dL, p=0.04) and glycated hemoglobin (7.6±2.3 vs. 6.8±1.9%, p=0.03). Plasma aldosterone (137.9±102.0 vs. 92.6±67.9pg/ml, p=0.03) as well as leptin levels (24.4±17.2 vs. 36.4±23.5ng/ml, p=0.01) were also higher in OBS compared with LNR group. Multiple linear regression indicated that glucose level is independently associated with obesity in RHTN patients. CONCLUSIONS: Our findings demonstrated that a greater body mass index may be determinantfor deregulating glucose metabolism as well as aldosterone and leptin levels in resistant hypertensive subjects.
JUSTIFICATIVA E OBJETIVO: A obesidade é uma característica comum da hipertensão arterial resistente (HAR) e é considerado um forte fator de risco para a falta de controle da pressão arterial. Além disso, o aumento dos níveis de aldosterona tem sido associado ao prejuízo do metabolismo da glicose e pode interagir com o tecido adiposo desregulando adipocinas inflamatórias, tais como a leptina. Este estudo teve como objetivo verificar a influência da obesidade nos níveis plasmáticos de aldosterona e leptina, bem como nos marcadores do metabolismo da glicose em indivíduos com hipertensão arterial resistente. MÉTODOS: Noventa e um pacientes foram divididos em dois subgrupos pela média de índice de massa corporal(IMC): (i) obesos (OBS, N=41, IMC>31,5kg/m2) e (ii) não obesos (nOBS, N=50, IMC<31,5kg/m2). Nós determinamos a composição corporal por bioimpedância (BIA 450). A glicemia de jejum, a hemoglobina glicada (HbA1c), bem como os níveis plasmáticos de aldosterona (radioimunoensaio) e leptina (ensaio imunoenzimático) também foram avaliados. RESULTADOS: O subgrupo OBS apresentou o metabolismo da glicose alterado pela glicemia de jejum (129±48 vs. 107±32mg/dL, p=0,04) e hemoglobina glicada (7,6±2,3 vs. 6,8±1,9%, p=0,03). Os níveis de aldosterona (137,9±102,0 vs. 92,6±67,9pg/ml, p=0,03), assim como os de leptina (24,4±17,2 vs. 36,4±23,5ng/ml, p=0,01)também estavam mais elevados em OBS quando comparados ao grupo nOBS. A análise de regressão linear múltipla indicou que o nível de glicose foi independentemente associado à obesidade em pacientes hipertensão arterial resistente. Conclusões: Nossos resultados demonstraram que o índice de massa corporal pode ser determinante para desregular o metabolismo da glicose, bem como os níveis de aldosterona e leptina em indivíduos hipertensos resistentes.
Subject(s)
Humans , Male , Female , Aldosterone , Blood Pressure Monitoring, Ambulatory , Body Mass Index , Diabetes Mellitus , Hypertension , Leptin , ObesityABSTRACT
BACKGROUND: Impaired endothelial function and arterial stiffness are associated with hypertension and are important risk factors for cardiovascular events. Reactive oxygen species reduce nitric oxide bioavailability and have a pivotal role in endothelial function. Resistant hypertension (RHTN) is characterized by blood pressure (BP) above goal (140/90mmHg) in spite of the concurrent use of ≥3 antihypertensive drugs of different classes. This study evaluated the association between 8-isoprostane levels, an oxidative stress marker, endothelial function and arterial stiffness, in RHTN. METHODS: Ninety-four RHTN and 55 well-controlled hypertensive (HT) patients were included. Plasma 8-isoprostane levels were determined by ELISA. Also, flow-mediated dilation (FMD) and pulse wave velocity (PWV) were evaluated to determine endothelial function and arterial stiffness, respectively. RESULTS: Levels of 8-isoprostane were markedly higher in RHTN compared to HT patients (22.5±11.2 vs. 17.3±9.8pg/ml, p<0.05, respectively). A significant inverse correlation was observed between FMD and 8-isoprostane (r=-0.35, p=0.001) in RHTN. Finally, multiple logistic regression revealed that 8-isoprostane was a significant predictor of endothelial dysfunction (FMD≤median) in RHTN group. CONCLUSION: RHTN showed markedly higher oxidative stress measured by 8-isoprostane, compared to HT patients. Taken together, our findings suggest the involvement of oxidative stress in endothelial function in RHTN.
