Suplementação de antioxidantes no tratamento da lesão pulmonar aguda: meta-análise / Antioxidant supplementation for the treatment of acute lung injury: a meta-analysis

OBJETIVO: A pesquisa foi conduzida de maneira a se esclarecer, através de uma meta-análise, as evidências da suplementação de antioxidantes como terapia adjuvante na prevenção dos danos oxidativos e melhora do desfecho clínico, tais como mortalidade, tempo de hospitalização e ventilação mecânica. MÉTODOS: A estratégia de busca de ensaios clínicos randomizados (ECRs) envolveu a participação de dois pesquisadores que avaliaram, de forma independente, a qualidade metodológica de cada artigo, disponível full text, nas bases de dados PubMed, ISI of Knowledge e ScienceDirect. RESULTADOS: Foram extraídos 110 estudos dos últimos 10 anos, porém somente 30 artigos preencheram os critérios metodológicos (ensaios controlados, randomizados, cego e estatisticamente significativo), totalizando 241 animais e 256 pacientes. Este trabalho encontrou um OR de 0,45 [intervalo de confiança (IC) 95 por cento: 0,26 - 0,79] para a mortalidade na comparação do grupo experimental com placebo (6 estudos, n = 256), um OR de de 0,46 [intervalo de confiança (IC) 95 por cento: 0,26 - 0,87] para tempo de hospitalização e um OR de 0,63 [intervalo de confiança (IC) 95 por cento: 0,35 - 1,12] para o tempo de ventilação mecânica assistida entre os grupos. CONCLUSÃO: As evidências são conflitantes e, desta forma, ainda não é possível recomendar o uso rotineiro da suplementação com antioxidantes em pacientes criticamente enfermos.

OBJECTIVE: This meta-analysis was performed to evaluate the evidence supporting antioxidant supplementation as an adjunct therapy to prevent oxidative damage and improve the clinical outcomes (mortality, length of hospital stay and duration of mechanical ventilation). METHODS: The search strategy for randomized controlled trials (RCTs) involved the participation of two researchers who independently assessed the methodological quality of each full-text article that was available in the PubMed, ISI WEB of Knowledge and ScienceDirect databases. RESULTS: We extracted 110 studies from the past 10 years, but only 30 articles met the methodological criteria (RCT, blinded and statistically significant results), for a total of 241 animals and 256 patients. This study found an odds ratio (OR) of 0.45 [95 percent confidence interval (CI): 0.26 to 0.79] for death in the experimental group compared with placebo (six trials, n = 256), an OR of 0.46 [95 percent CI: 0.26 to 0.87] for hospitalization time and an OR of 0.63 [95 percent CI: 0.35 to 1.12] for mechanical ventilation time between groups. CONCLUSION: Conflicting evidence makes it impossible to recommend the routine use of antioxidant supplementation in critically ill patients.

Antioxidant supplementation for the treatment of acute lung injury: a meta-analysis. / Suplementação de antioxidantes no tratamento da lesão pulmonar aguda: meta-análise.

OBJECTIVE: This meta-analysis was performed to evaluate the evidence supporting antioxidant supplementation as an adjunct therapy to prevent oxidative damage and improve the clinical outcomes (mortality, length of hospital stay and duration of mechanical ventilation). METHODS: The search strategy for randomized controlled trials (RCTs) involved the participation of two researchers who independently assessed the methodological quality of each full-text article that was available in the PubMed, ISI WEB of Knowledge and ScienceDirect databases. RESULTS: We extracted 110 studies from the past 10 years, but only 30 articles met the methodological criteria (RCT, blinded and statistically significant results), for a total of 241 animals and 256 patients. This study found an odds ratio (OR) of 0.45 [95% confidence interval (CI): 0.26 to 0.79] for death in the experimental group compared with placebo (six trials, n = 256), an OR of 0.46 [95% CI: 0.26 to 0.87] for hospitalization time and an OR of 0.63 [95% CI: 0.35 to 1.12] for mechanical ventilation time between groups. CONCLUSION: Conflicting evidence makes it impossible to recommend the routine use of antioxidant supplementation in critically ill patients.

Effects of nasal continuous positive airway pressure treatment on oxidative stress and adiponectin levels in obese patients with obstructive sleep apnea.

BACKGROUND: Obesity and obstructive sleep apnea (OSA) are both associated with the prevalence of major cardiovascular illnesses and certain common factors they are considered responsible for, such as stress oxidative increase, sympathetic tonus and resistance to insulin. OBJECTIVE: The aim of the present study was to compare the effect of continuous positive airway pressure (CPAP) on oxidative stress and adiponectin levels in obese patients with and without OSA. METHODS: Twenty-nine obese patients were categorized into 3 groups: group 1: 10 individuals without OSA (apnea-hypopnea index, AHI or=20) who did not use CPAP; group 3: 9 patients with moderate to severe OSA (AHI >or=20) who used CPAP. RESULTS: Group 3 showed significant differences before and after the use of CPAP, in the variables of diminished production of superoxide, and increased nitrite and nitrate synthesis and adiponectin levels. Positive correlations were seen between the AHI and the superoxide production, between the nitrite and nitrate levels and the adiponectin levels, between superoxide production and the HOMA-IR, and between AHI and the HOMA-IR. Negative correlations were found between AHI and the nitrite and nitrate levels, between the superoxide production and that of nitric oxide, between the superoxide production and the adiponectin levels, between AHI and the adiponectin levels, and between the nitrite and nitrate levels and the HOMA-IR. CONCLUSIONS: This study demonstrates that the use of CPAP can reverse the increased superoxide production, the diminished serum nitrite, nitrate and plasma adiponectin levels, and the metabolic changes existing in obese patients with OSA.

[Obstructive sleep apnea contribution to oxidative stress in obesity]. / Contribuição da apnéia obstrutiva do sono para o estresse oxidativo da obesidade.

OBJECTIVE: The aim of this paper was to check the influence of obstructive sleep apnea (OSA) on obesity oxidative stress and CPAP (Continuous Positive Airway Pressure) effect on oxidative stress and in these patients. METHODS: Twenty nine male patients considered obese (BMI > 30 kg/m(2)) were divided into 3 groups: a) Group I: 10 OSA free patients (apnea-hipopnea index (AHI) < 5); b) Group 2: 10 with moderate to serious OSA (AHI > 20); c) Group 3: 9 with OSA from moderate to serious (AHI > 20) using CPAP, minimum 4 hours/night for 2 months. RESULTS: Significant differences before and after CPAP usage were observed in group 3 in the following variables: reduction of superoxide (SO) production [13.2 (10.3-19.6) vs. 10.5 (5.8-11.8) nmoles O2(-)/2 x 10(6) PMN] and increase in serum nitrite/nitrates levels [24.5 (16.7-33.5) vs. 49.5 (39.3-58.1) microM]. Positive correlation between Apnea-Hypopnea Index (AHI) and SO (r = 0,726) and negative correlation was observed between AHI and serum nitrite/nitrates levels (r = - 0.867). CONCLUSIONS: In conclusion, oxidative stress present in obesity is elevated by OSA and CPAP treatment can rise the levels of SO and can decrease serum nitrite/nitrates present in obese patients with OSA.

Contribuição da apnéia obstrutiva do sono para o estresse oxidativo da obesidade / Obstructive sleep apnea contribution to oxidative stress in obesity

OBJETIVO: O objetivo do trabalho foi verificar a influência da apnéia obstrutiva do sono (AOS) sobre o estresse oxidativo da obesidade e o efeito do pressão positiva de vias aéreas (CPAP) nestes pacientes. MÉTODOS: Os pacientes com IMC > 30 kg/m² foram divididos em: a) grupo 1: dez indivíduos sem AOS; b) grupo 2: dez portadores de AOS que não fizeram o uso do CPAP; e c) grupo 3: nove portadores de AOS que fizeram uso do CPAP durante dois meses. RESULTADOS: O grupo 3 apresentou, após o uso do CPAP, redução na produção de superóxido (SO) [13,2 (10,3-19,6) versus 10,5 (5,8-11,8) nmoles O2-/2×10(6) PMN] e aumento na síntese de nitritos e nitratos séricos [24,5 (16,7-33,5) versus 49,5 (39,3-58,1) µM]. Também foi verificada correlação positiva entre o índice apnéia-hipopnéia (IAH) e a produção de SO (r = 0,726) e negativa entre o IAH e os níveis de nitritos e nitratos séricos (r = -0,867). CONCLUSÕES: O estresse oxidativo presente na obesidade é exacerbado pela AOS e o uso do CPAP promove aumento nos níveis de nitritos e nitratos séricos, bem como reduções na produção de SO neste pacientes.

OBJECTIVE: The aim of this paper was to check the influence of obstructive sleep apnea (OSA) on obesity oxidative stress and CPAP (Continuous Positive Airway Pressure) effect on oxidative stress and in these patients. METHODS: Twenty nine male patients considered obese (BMI > 30kg/m²) were divided into 3 groups: a) Group I: 10 OSA free patients (apnea-hipopnea index (AHI) < 5); b) Group 2: 10 with moderate to serious OSA (AHI > 20); c) Group 3: 9 with OSA from moderate to serious (AHI > 20) using CPAP,, minimum 4 hours/night for 2 months. RESULTS: Significant differences before and after CPAP usage were observed in group 3 in the following variables: reduction of superoxide (SO) production [13,2 (10,3-19,6) vs. 10,5 (5,8-11,8) nmoles O2- /2x10(6) PMN] and increase in serum nitrite/nitrates levels [24,5 (16,7-33,5) vs. 49,5 (39,3-58,1) µM]. Positive correlation between Apnea-Hypopnea Index (AHI) and SO (r = 0,726) and negative correlation was observed between AHI and serum nitrite/nitrates levels (r = - 0,867). CONCLUSIONS: In conclusion, oxidative stress present in obesity is elevated by OSA and CPAP treatment can rise the levels of SO and can decrease serum nitrite/nitrates present in obese patients with OSA.