Parkkinen J, von Bonsdorff L, Peltonen S, Grönhagen-Riska C, Rosenlöf K
Finnish Red Cross Blood Transfusion Service, Department of Medicine, Helsinki University Hospital, Helsinki, Finland.
Nephrol Dial Transplant. 2000 Nov;15(11):1827-34. doi: 10.1093/ndt/15.11.1827.
I.v. iron is commonly administered to haemodialysis patients suffering from anaemia to improve their response to erythropoietin therapy. It has been unclear whether routinely used doses of i.v. iron preparations could result in iron release into plasma in amounts exceeding the iron binding capacity of transferrin. Here, we have studied the effect of 100 mg of iron saccharate given as an i.v. injection on transferrin saturation and the appearance of potentially harmful catalytically active iron.
We followed serum iron, transferrin and transferrin-saturation before and 5-210 min after administration of iron saccharate in 12 patients on chronic haemodialysis due to end-stage renal disease. We measured catalytically active iron by the bleomycin-detectable iron (BDI) assay and transferrin iron forms by urea gel electrophoresis, and studied iron-dependent growth of Staphylococcus epidermidis inoculated into the serum samples in vitro.
The iron saccharate injection resulted in full transferrin saturation and appearance of BDI in the serum in seven out of the 12 patients. BDI appeared more often in patients with a low serum transferrin concentration, but it was not possible to identify patients at risk based on serum transferrin or ferritin level before i.v. iron. The average transferrin saturation and BDI level increased until the end of the follow-up time of 3.5 h. The appearance of BDI resulted in loss of the ability of patient serum to resist the growth of S. epidermidis, which was restored by adding iron-free apotransferrin to the serum. Iron saccharate, added to serum in vitro, released only little iron and promoted only slow bacterial growth, but caused falsely high transferrin saturation by one routinely used serum iron assay.
The results indicate that 100 mg of iron saccharate often leads to transferrin oversaturation and the presence of catalytically active iron within 3.5 h after i.v. injection. As catalytically active iron is potentially toxic and may promote bacterial growth, it may be recommendable to use dosage regimens for i.v. iron that would not cause transferrin oversaturation.
静脉注射铁剂常用于治疗患有贫血的血液透析患者，以改善其对促红细胞生成素治疗的反应。常规使用剂量的静脉注射铁剂是否会导致铁释放到血浆中的量超过转铁蛋白的铁结合能力，目前尚不清楚。在此，我们研究了静脉注射100mg蔗糖铁对转铁蛋白饱和度和潜在有害的催化活性铁出现的影响。
我们在12例因终末期肾病接受慢性血液透析的患者中，于静脉注射蔗糖铁之前及之后5-210分钟，追踪血清铁、转铁蛋白及转铁蛋白饱和度。我们通过博来霉素可检测铁（BDI）测定法测量催化活性铁，并通过尿素凝胶电泳研究转铁蛋白铁形式，同时在体外研究接种到血清样本中的表皮葡萄球菌的铁依赖性生长。
在12例患者中，有7例静脉注射蔗糖铁后导致转铁蛋白完全饱和且血清中出现BDI。BDI在血清转铁蛋白浓度低的患者中更常出现，但在静脉注射铁剂前，无法根据血清转铁蛋白或铁蛋白水平识别有风险的患者。平均转铁蛋白饱和度和BDI水平在长达3.5小时的随访期结束前持续升高。BDI的出现导致患者血清抵抗表皮葡萄球菌生长的能力丧失，通过向血清中添加无铁脱铁转铁蛋白可恢复该能力。在体外向血清中添加蔗糖铁，仅释放少量铁并仅促进缓慢的细菌生长，但通过一种常用的血清铁测定法会导致转铁蛋白饱和度出现假高值。
结果表明，100mg蔗糖铁静脉注射后，常在3.5小时内导致转铁蛋白过度饱和及催化活性铁的存在。由于催化活性铁具有潜在毒性且可能促进细菌生长，推荐使用不会导致转铁蛋白过度饱和的静脉注射铁剂给药方案。
