Biomarkers for oxidative stress in acute lung injury induced in rabbits submitted to different strategies of mechanical ventilation.

Oxidative damage has been said to play an important role in pulmonary injury, which is associated with the development and progression of acute respiratory distress syndrome (ARDS). We aimed to identify biomarkers to determine the oxidative stress in an animal model of acute lung injury (ALI) using two different strategies of mechanical ventilation. Rabbits were ventilated using either conventional mechanical ventilation (CMV) or high-frequency oscillatory ventilation (HFOV). Lung injury was induced by tracheal saline infusion (30 ml/kg, 38°C). In addition, five healthy rabbits were studied for oxidative stress. Isolated lymphocytes from peripheral blood and lung tissue samples were analyzed by alkaline single cell gel electrophoresis (comet assay) to determine DNA damage. Total antioxidant performance (TAP) assay was applied to measure overall antioxidant performance in plasma and lung tissue. HFOV rabbits had similar results to healthy animals, showing significantly higher antioxidant performance and lower DNA damage compared with CMV in lung tissue and plasma. Total antioxidant performance showed a significant positive correlation (r = 0.58; P = 0.0006) in plasma and lung tissue. In addition, comet assay presented a significant positive correlation (r = 0.66; P = 0.007) between cells recovered from target tissue and peripheral blood. Moreover, antioxidant performance was significantly and negatively correlated with DNA damage (r = -0.50; P = 0.002) in lung tissue. This study indicates that both TAP and comet assay identify increased oxidative stress in CMV rabbits compared with HFOV. Antioxidant performance analyzed by TAP and oxidative DNA damage by comet assay, both in plasma, reflects oxidative stress in the target tissue, which warrants further studies in humans.

Síndrome metabólica: atualização de critérios diagnósticos e impacto do estresse oxidativo na patogênese: [revisão] / Metabolic syndrome: updated diagnostic criteria and impact of oxidative stress on metabolic syndrome pathogenesis: [review]

JUSTIFICATIVA E OBJETIVOS: Tem sido estimado que a síndrome metabólica (SM) afeta uma substancial porcentagem da população idosa e de média idade, conferindo um aumento de risco para o desenvolvimento de doenças cardiovasculares e diabetes mellitus do tipo 2 (DM2), riscos esses que irão conduzir a uma situação economicamente insustentável nos próximos anos. O objetivo deste estudo foi apresentar critérios diagnósticos atualizados, detalhar o papel do estresse oxidativo em cada um dos diversos sinais, sumarizar os principais estudos clínicos e experimentais,e abordar o tratamento com antioxidantes. CONTEÚDO: SM corresponde a um conjunto de anormalidades,incluindo entre outros sinais, aumento da pressão arterial,alteração da glicemia, hipertrigliceridemia, baixos níveis de lipoproteína-colesterol de baixa densidade e obesidade abdominal. Estresse oxidativo é um importante mecanismo no desenvolvimentodos sinais da SM. CONCLUSÃO: Embora o estresse oxidativo parecesse ser mecanismo determinante na SM, a prescrição de suplementação com antioxidantes não é recomendada de rotina.

BACKGROUND AND OBJECTIVES: Metabolic syndrome (MS) affects a substantial percentage of the middle-aged and elderly populations and confers increased risk for type 2 diabetes and cardiovascular disease that ultimately will lead to economically-unsustainable costs of health care in the next years. This review shows updated diagnostic criteria, detailing the role of oxidative stress in each sign, summarizing the main clinical andexperimental studies and approaching the antioxidant treatment. CONTENTS: MS correspond to a cluster of abnormalities, includin gamong other signs, raised blood pressure, dysglycemia, and elevated triglyceride levels, low high-density lipoprotein cholesterol levels, and abdominal obesity. Oxidative stress is importan tmechanism involved in the MS sign development. CONCLUSION: Although oxidative stress seems to play an importantrole in its pathophysiological mechanism, routine use of antioxidant supplements is not recommended.