Berger Mette M, Oudemans-van Straaten Heleen M
aAdult Intensive Care and Burns, University Hospital CHUV, Lausanne, Switzerland bDepartment of Intensive Care, VU University Medical Center, Amsterdam, the Netherlands.
Curr Opin Clin Nutr Metab Care. 2015 Mar;18(2):193-201. doi: 10.1097/MCO.0000000000000148.
Vitamin C is not only an essential nutrient involved in many anabolic pathways, but also an important player of the endogenous antioxidant defense. Low plasma levels are very common in critical care patients and may reflect severe deficiency states.
Vitamin C scavenges reactive oxygen species such as superoxide and peroxynitrite in plasma and cells (preventing damage to proteins, lipids and DNA), prevents occludin dephosphorylation and loosening of the tight junctions. Ascorbate improves microcirculatory flow impairment by inhibiting tumor-necrosis-factor-induced intracellular adhesion molecule expression, which triggers leukocyte stickiness and slugging. Clinical trials in sepsis, trauma and major burns testing high-dose vitamin C show clinical benefit. Restoration of normal plasma levels in inflammatory patients requires the administration of 3 g/day for several days, which is 30 times the daily recommended dose.
The recent research on the modulation of oxidative stress and endothelial protection offer interesting therapeutic perspectives, based on the biochemical evidence, with limited or even absent side-effects.
维生素C不仅是参与多种合成代谢途径的必需营养素，也是内源性抗氧化防御的重要参与者。血浆水平低在重症监护患者中非常常见，可能反映严重缺乏状态。
维生素C可清除血浆和细胞中的活性氧，如超氧化物和过氧亚硝酸盐（防止蛋白质、脂质和DNA受损），防止闭合蛋白去磷酸化和紧密连接松弛。抗坏血酸通过抑制肿瘤坏死因子诱导的细胞间粘附分子表达来改善微循环血流障碍，而这种表达会引发白细胞黏附和淤滞。在脓毒症、创伤和大面积烧伤患者中进行的高剂量维生素C临床试验显示出临床益处。炎症患者恢复正常血浆水平需要连续数天每天给予3克维生素C，这是每日推荐剂量的30倍。
基于生化证据，近期关于氧化应激调节和内皮保护的研究提供了有趣的治疗前景，且副作用有限甚至没有。
