Richer Stuart, Rudy David, Statkute Laisvyde, Karofty Kurt, Frankowski Jim
Department of Family Medicine, Finch University of Health Sciences/Chicago Medical School, North Chicago, IL 60064, USA.
Am J Ther. 2002 Jan-Feb;9(1):25-8. doi: 10.1097/00045391-200201000-00006.
Iron (Fe) is a tightly metabolically controlled mineral and growth factor for all living cells. Iron not bound in erythrocyte hemoglobin is transported by the plasma iron transport protein transferrin (Tf) and bound within cells by ferritin. Apo-Tf and apo-hemopexin are also known to be made locally in the retina. Free Fe is cytotoxic, promotes oxidation/lipid peroxidation, has been implicated as a risk factor in cardiac disease, and is itself associated with age-related macular degeneration (ARMD), the leading cause of blindness in aging western societies. The authors evaluated Fe overload serum markers and dietary intake in patients with atrophic ARMD. After obtaining informed consent, an Fe panel consisting of serum Fe, total Fe binding capacity (TIBC), and ferritin was performed on 75 veterans (70 men, five women) with an average age of 75 years with a diagnosis of atrophic ARMD by combined criteria of International Retinal Classification and psychophysical/symptom abnormalities. Tf saturation was calculated by dividing serum Fe concentration by TIBC. Dietary iron with and without supplementation and vitamin C intake were determined for 86 patients using the Harvard School of Public Health/Department of Nutrition Food Frequency Questionnaire. Statistically significant correlations (P <0.1) were found between serum and dietary Fe (r = -.26), between serum Fe and serum ferritin (r =.34), and between dietary Fe and dietary vitamin C (r =.30). The data on mostly male geriatric veterans with atrophic ARMD indicate that single time-point assessment of systemic Fe status and dietary Fe is not useful. However, serial multiple-year data, correlating Fe markers with disease, may still be important. Also, because Fe transport proteins do not cross the blood-retina barrier, the local cellular toxic effects of Fe must also be considered.
铁（Fe）是一种在代谢上受到严格调控的矿物质，也是所有活细胞的生长因子。未结合在红细胞血红蛋白中的铁由血浆铁转运蛋白转铁蛋白（Tf）运输，并在细胞内与铁蛋白结合。已知脱铁转铁蛋白和脱血红素结合蛋白也在视网膜局部产生。游离铁具有细胞毒性，会促进氧化/脂质过氧化，被认为是心脏病的危险因素，其本身还与年龄相关性黄斑变性（ARMD）有关，ARMD是西方老龄化社会中失明的主要原因。作者评估了萎缩性ARMD患者的铁过载血清标志物和饮食摄入量。在获得知情同意后，对75名平均年龄为75岁、根据国际视网膜分类及心理物理学/症状异常综合标准诊断为萎缩性ARMD的退伍军人（70名男性，5名女性）进行了包括血清铁、总铁结合力（TIBC）和铁蛋白的铁指标检测。转铁蛋白饱和度通过血清铁浓度除以TIBC来计算。使用哈佛公共卫生学院/营养系食物频率问卷，对86名患者的饮食铁摄入量（包括是否补充铁）和维生素C摄入量进行了测定。结果发现血清铁与饮食铁之间（r = -0.26）、血清铁与血清铁蛋白之间（r = 0.34）以及饮食铁与饮食维生素C之间（r = 0.30）存在统计学显著相关性（P < 0.1）。这些主要针对患有萎缩性ARMD的老年男性退伍军人的数据表明，对全身铁状态和饮食铁进行单次时间点评估并无用处。然而，将铁标志物与疾病相关联的连续多年数据可能仍然很重要。此外，由于铁转运蛋白不能穿过血视网膜屏障，铁的局部细胞毒性作用也必须予以考虑。
