抗氧化剂在临床营养中的作用
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中国临床营养杂志000114Antioxidants in clinical nutrition
Hans K ,Biesalski MD
(Dept. of Biological Chemistry and Nutrition, University of Hoheneim , D 70593 Stuttgart, Germany)
There is a godd evidence from experimental and clinical studies that trauma and injury result in a dyshalance of the antioxidative system due to an increase of ROS fromation and a decrease of exogenous antioxidants. Clinical studies indicate that a loss of antioxidants is accompanied by an increased risk for sepsis and MOF. Consequently a supplementation with antioxidants should have a beneficial effect. Only few studies exist which explore the supplementation of antioxidants and other markers of oxidative stress, such as TBARS, or clinically relevant outcome variables. Rabl and coworkers showed a slight but significant effect on ereatinine values and dearence in patients undergoing kidney transplantation and treated with a multivitamin infusion during surgery (before reperfusion of the transplanted kidney). Intravenous supplementation of n-acetyl-cysteine plus 1g vitamin C and 400 rag vitamin E given after an initial loading dose of NAC ( 150mg/kg for 30min) in patients with septic shock were without effect an clinical outcome ( Galley et al. 1997). However antioxidant supplementation results in statistically significant hemodynamic changes (decrease of SVR 1 and increase of cardiac index). The authors conclude that this is due to a potention of NO-formation by the administration of antioxidants. Whather this has any benefit on the outcome of the patients remains to be further elucidated. A replacement therapy of micronutrients according to recommended daily allowences had no effect on clinical outcome in ARDS patients. However, supplementation with low vitamin concentrations might be not a successful approach due to the high need for antioxidants. Further more sepsis and ARDS development seems to be fovoured by oxidative stress during on early stage. Consequently antioxidant replacement therapy during manifest sepsis and ARDS development seems to be fovoured by oxidative stress during on early stage. Consequently antioxidant replacement therapy during manifest-sepsis or organ falure might be to late. Punz and coworkers showed a beneficial effect of multivitamin administration on markers of oxidative stress and on skeletal muscle morphology when the solution was administered before the onset of ischemia but not if administered before onset of reperfusion. This confirms earlier results of this group that the superoxide anion production takes place during the ischemia phase (Huk et al. 1997). A supplementation prior ischemia might not only prevent ROS-formation but might also compensate the less of antioxidants during ischemia as demonstrated in a recent study. A dysbalance of the antioxidant network which is not compensated " in time" might induce a cascade of secondary events which at least cannot or only in part be compensated by an antioxidant replacement therapy.
, 百拇医药
临床和实验室研究的结果都表明，创伤可引起ROS的形成增加，外源性抗氧化剂减少，导致抗氧化系统失平衡。临床研究提示，抗氧化剂的减少增加了发生严重感染和MOF的危险，补充抗氧化剂有益。只有很少的研究观察补充抗氧化剂和氧化反应有关的临床指标的关系。Rabl报告在肾移植病人术中(移植肾再灌注前)，补充多种维生素溶液可明显改善肌酐水平和清除能力。感染性休克病人，在给予负荷量的n-乙酰-半胱氨酸(NAC，150mg/kg 30分钟)后，静脉补充NAC加1克维生素C和400mg维生素E，没有观察到临床疗效(Galley et al，1997)。补充抗氧化剂可引起明显的血液动力学改变(SVRI降低，心脏指数增加)。作者认为这是因为补充抗氧化剂增加了NO的形成，是否有利于病人的预后还需进一步的研究。根据每日推荐量进行的微量元素的替代治疗，对ARDS病人的预后没有影响。补充低剂量的维生素不是有效的治疗措施，因为机体对抗氧化剂的需要量大。在疾病早期，严重感染和ARDS可能因为氧化作用而加重。因此，当感染或器官功能衰竭明显时，补充抗氧化剂可能为时已晚。Punz的研究表明，在缺血发生前补充多种维生素对氧化反应的指标和骨骼肌形态学都有有利影响，但在再灌注前补充维生素则无作用。这也证明作者以前的研究结果，过氧化物离于是在缺血期产生(Huk et al，1997)。在缺血发生前补充抗氧化剂不仅可以抑制ROS的形成，而且可以补偿缺血期抗氧化剂的减少。抗氧化系统的失平衡如果不被及时纠正，可能导致继发的病理过程，而这些变化将不能或只能部分由补充抗氧化剂得到纠正。, http://www.100md.com
单位：
关键词：
中国临床营养杂志000114Antioxidants in clinical nutrition
Hans K ,Biesalski MD
(Dept. of Biological Chemistry and Nutrition, University of Hoheneim , D 70593 Stuttgart, Germany)
There is a godd evidence from experimental and clinical studies that trauma and injury result in a dyshalance of the antioxidative system due to an increase of ROS fromation and a decrease of exogenous antioxidants. Clinical studies indicate that a loss of antioxidants is accompanied by an increased risk for sepsis and MOF. Consequently a supplementation with antioxidants should have a beneficial effect. Only few studies exist which explore the supplementation of antioxidants and other markers of oxidative stress, such as TBARS, or clinically relevant outcome variables. Rabl and coworkers showed a slight but significant effect on ereatinine values and dearence in patients undergoing kidney transplantation and treated with a multivitamin infusion during surgery (before reperfusion of the transplanted kidney). Intravenous supplementation of n-acetyl-cysteine plus 1g vitamin C and 400 rag vitamin E given after an initial loading dose of NAC ( 150mg/kg for 30min) in patients with septic shock were without effect an clinical outcome ( Galley et al. 1997). However antioxidant supplementation results in statistically significant hemodynamic changes (decrease of SVR 1 and increase of cardiac index). The authors conclude that this is due to a potention of NO-formation by the administration of antioxidants. Whather this has any benefit on the outcome of the patients remains to be further elucidated. A replacement therapy of micronutrients according to recommended daily allowences had no effect on clinical outcome in ARDS patients. However, supplementation with low vitamin concentrations might be not a successful approach due to the high need for antioxidants. Further more sepsis and ARDS development seems to be fovoured by oxidative stress during on early stage. Consequently antioxidant replacement therapy during manifest sepsis and ARDS development seems to be fovoured by oxidative stress during on early stage. Consequently antioxidant replacement therapy during manifest-sepsis or organ falure might be to late. Punz and coworkers showed a beneficial effect of multivitamin administration on markers of oxidative stress and on skeletal muscle morphology when the solution was administered before the onset of ischemia but not if administered before onset of reperfusion. This confirms earlier results of this group that the superoxide anion production takes place during the ischemia phase (Huk et al. 1997). A supplementation prior ischemia might not only prevent ROS-formation but might also compensate the less of antioxidants during ischemia as demonstrated in a recent study. A dysbalance of the antioxidant network which is not compensated " in time" might induce a cascade of secondary events which at least cannot or only in part be compensated by an antioxidant replacement therapy.
, 百拇医药
临床和实验室研究的结果都表明，创伤可引起ROS的形成增加，外源性抗氧化剂减少，导致抗氧化系统失平衡。临床研究提示，抗氧化剂的减少增加了发生严重感染和MOF的危险，补充抗氧化剂有益。只有很少的研究观察补充抗氧化剂和氧化反应有关的临床指标的关系。Rabl报告在肾移植病人术中(移植肾再灌注前)，补充多种维生素溶液可明显改善肌酐水平和清除能力。感染性休克病人，在给予负荷量的n-乙酰-半胱氨酸(NAC，150mg/kg 30分钟)后，静脉补充NAC加1克维生素C和400mg维生素E，没有观察到临床疗效(Galley et al，1997)。补充抗氧化剂可引起明显的血液动力学改变(SVRI降低，心脏指数增加)。作者认为这是因为补充抗氧化剂增加了NO的形成，是否有利于病人的预后还需进一步的研究。根据每日推荐量进行的微量元素的替代治疗，对ARDS病人的预后没有影响。补充低剂量的维生素不是有效的治疗措施，因为机体对抗氧化剂的需要量大。在疾病早期，严重感染和ARDS可能因为氧化作用而加重。因此，当感染或器官功能衰竭明显时，补充抗氧化剂可能为时已晚。Punz的研究表明，在缺血发生前补充多种维生素对氧化反应的指标和骨骼肌形态学都有有利影响，但在再灌注前补充维生素则无作用。这也证明作者以前的研究结果，过氧化物离于是在缺血期产生(Huk et al，1997)。在缺血发生前补充抗氧化剂不仅可以抑制ROS的形成，而且可以补偿缺血期抗氧化剂的减少。抗氧化系统的失平衡如果不被及时纠正，可能导致继发的病理过程，而这些变化将不能或只能部分由补充抗氧化剂得到纠正。, http://www.100md.com