Análise de biomarcadores de balanço redox em portadores de hipertensão arterial primária: uma avaliação segundo técnicas bioquímicas, cromatográficas e espectrofotométricas

Abstract

The participation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in systemic arterial hypertension (SAH) has been described in recent papers, which indicate the importance of studying the phenomena that influences the redox environment in blood of patients with high blood pressure (hypertenses), as well as the dietary aspects that could be related to it. Analysis of blood from 20/433 people with hypertension and 21/63 controls, for superoxide dismutase (SOD), catalase (CAT), serum glutathione peroxidase (GPx), glutathione (GSH), Vitamin C, transferrin, ceruloplasmin, malondialdehyde (MDA) and carbonyl groups were performed, after the patients’ consent. The patients were selected according to their body mass index (BMI) (≥ 18.5 and ≤ 30 Kg/m2), glicemy (≤ 100 mg/dL), serum cholesterol (≤ 200 mg/dL), as non-smokers, women not pregnant or menopausal, not using allopurinol or probucol. The dietary ingestion of fruits, legumes, vegetables, energy and macronutrients Na, K, fibre, Cu, Zn and Se was also studied. The group selected was subjected to four weeks of preparation (no use of nutritional supplements, paracetamol, dexamethasone or alcohol) for subsequent analysis of their blood in terms of redox environment. People with hypertension when compared with controls showed lower levels of CAT (p 0.013), GSH (p 0.003), and MDA (p 0.014), higher levels of GPx (p 0.0001) and ceruloplasmin (0.015); deficient ingestion of vegetables, legumes and Vitamin C (p 0.045), Fe (p 0.043), Cu (p 0.003) and Zn (p 0.026). Positive association was verified only between decreased levels of ceruloplasmin and elevated levels of Vitamin C, in the control group. The results herein presented differ somewhat from the literature, whose data, in general, had shown lower levels of antioxidant enzymes and elevated concentration of markers of oxidative damage in individuals with hypertension. In the present study, elevated levels of GPx and lower levels of MDA were obtained. However, this also agrees with the hypothesis of oxidative stress in hypertension, through an alternative explanation. In case of excess of ONOO, a hypertension characteristic reactive species, there is a greater demand on the enzyme; and with a higher concentration of GPx, whose activity is directed towards peroxides, there would be a reduction on lipid peroxidation and consequent decrease of MDA. It is impossible, at this moment, to define the exact role of the oxidative stress, if cause or consequence. However, the occurrence of oxidative stress in hypertension was verified, corroborating earlier reports.