BACKGROUND Increased generation of reactive oxygen and nitrogen species in chronic kidney disease (CKD) patients leads to increased oxidative stress. The antioxidant capacity of folic acid has been shown to scavenge radicals efficiently. OBJECTIVE The current study was carried out to examine the effects of folic acid treatment on biochemical and oxidative stress biomarkers in patients in different stages of CKD. METHODS This was a randomized, non-blinded, clinical trial that assessed the effects of 3 months of treatment with 5 mg of folic acid daily or no treatment in 113 outpatients within CKD stages 3a and 3b. At the end of the intervention, we analyzed the data of 66 patients treated with folic acid and 47 in the control group. Serum homocysteine levels and biochemical and oxidative/nitrosative stress biomarkers were analyzed in all patients. RESULTS In most patients, folic acid treatment normalized homocysteine levels and increased antioxidant enzyme activity (paraoxonase 1) and decreased sulfhydryl (SH) groups. In addition, oxidative biomarkers (products of nitric oxide and lipid hydroperoxide) were significantly lower post-treatment compared to baseline in the active intervention group. In the no active intervention group, no statistically significant effects were found on the oxidative and biochemical biomarkers. CONCLUSION Folic acid treatment in stages 3a-4 CKD patients effectively ameliorated their hyperhomocysteinemia and increased the activity of antioxidant enzymes, as well as decreased the levels of pro-oxidant biomarkers in stage G3a and G3b CKD patients. Folic acid treatment attenuated oxidative/nitrosative stress and may be considered as a possible strategy to improve redox status and diminish the damages associated with oxidative/nitrosative stress in CKD patients. Further studies are needed to confirm these findings. Clinical Trials Registration No.: This study is registered in the Brazilian Record of Clinical Trials (ReBEC), under reference RBR-2bfthr.

中文翻译：

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叶酸短期治疗以减少慢性肾病患者氧化应激的随机试验。

背景技术慢性肾病(CKD)患者中活性氧和氮的生成增加导致氧化应激增加。叶酸的抗氧化能力已被证明可以有效地清除自由基。目的本研究旨在探讨叶酸治疗对CKD不同阶段患者生化和氧化应激生物标志物的影响。方法 这是一项随机、非盲法临床试验，评估了 113 名 CKD 3a 和 3b 期门诊患者每天 5 mg 叶酸治疗或不治疗 3 个月的效果。在干预结束时，我们分析了 66 名接受叶酸治疗的患者和 47 名对照组患者的数据。对所有患者的血清同型半胱氨酸水平以及生化和氧化/亚硝化应激生物标志物进行了分析。结果 在大多数患者中，叶酸治疗使同型半胱氨酸水平正常化并增加抗氧化酶活性（对氧磷酶 1）和减少巯基（SH）组。此外，与主动干预组的基线相比，治疗后的氧化生物标志物（一氧化氮和脂质氢过氧化物的产物）显​​着降低。在无积极干预组中，未发现对氧化和生化生物标志物的统计学显着影响。结论 3a-4 期 CKD 患者的叶酸治疗有效改善了 G3a 和 G3b 期 CKD 患者的高同型半胱氨酸血症，增加了抗氧化酶的活性，并降低了促氧化生物标志物的水平。叶酸治疗可减轻氧化/亚硝化应激，并可能被认为是改善 CKD 患者氧化还原状态和减少与氧化/亚硝化应激相关的损害的一种可能策略。需要进一步的研究来证实这些发现。临床试验注册号：本研究在巴西临床试验记录 (ReBEC) 中注册，参考号为 RBR-2bfthr。