Collard Keit J, White Desley L
University of Plymouth, Faculty of Health and Human Sciences, Plymouth, United Kingdom.
Blood Transfus. 2014 Oct;12(4):527-32. doi: 10.2450/2014.0271-13. Epub 2014 Jun 5.
Recent studies have shown large increases in non-transferrin-bound iron (NTBI) and biomarkers of oxidative stress in the extracellular medium of packed red blood cell units during storage. It has been further suggested that transfusion-mediated iron and oxidative load may contribute to transfusion-related morbidity in premature babies. The origin and nature of the NTBI is currently unclear, but the release of iron from oxidatively modified haemoglobin and haem has been suggested. The purpose of this study was to investigate whether this may be the case.
The concentration of haem in the extracellular fluid of paediatric packed cell units stored from 3 to 35 days was measured using a commercial haem assay. In vitro studies were conducted using haem (haemin; ferriprotoporphyrin IX chloride) to determine whether the NTBI assay was able to react with and measure iron associated with haem in the presence and absence of oxidising agents.
The level of haem in the extracellular fluid of paediatric packed cell units rose gradually from day 3 to day 21, then more rapidly to day 35. Very little NTBI was released from haem in the absence of oxidising agents, but the amount rose in a dose- and time-dependent manner in proportion to the oxidation of haem by incubation with H2O2.
The results of the study imply that the NTBI measured in previous studies may derive from the oxidatively modified haem that builds up in the extracellular fluid of packed red blood cell units during storage. The potential influence of this on transfusion mediated morbidity is discussed.
最近的研究表明，在红细胞浓缩液储存期间，细胞外介质中的非转铁蛋白结合铁（NTBI）和氧化应激生物标志物大幅增加。进一步表明，输血介导的铁和氧化负荷可能导致早产儿发生与输血相关的发病率。目前尚不清楚NTBI的来源和性质，但有人提出铁是从氧化修饰的血红蛋白和血红素中释放出来的。本研究的目的是调查是否如此。
使用商业血红素测定法测量储存3至35天的儿科红细胞浓缩液单位细胞外液中的血红素浓度。使用血红素（氯高铁血红素；氯化铁原卟啉IX）进行体外研究，以确定NTBI测定法在有无氧化剂的情况下是否能够与血红素相关的铁发生反应并进行测量。
儿科红细胞浓缩液单位细胞外液中的血红素水平从第3天到第21天逐渐上升，然后到第35天上升得更快。在没有氧化剂的情况下，血红素释放的NTBI很少，但与过氧化氢孵育使血红素氧化后，释放量呈剂量和时间依赖性增加。
研究结果表明，先前研究中测量的NTBI可能来自储存期间红细胞浓缩液单位细胞外液中积累的氧化修饰血红素。讨论了其对输血介导的发病率的潜在影响。
