Eckardt K U
Medical Clinic, Department of Nephrology and Intensive Care Medicine, Humboldt University Berlin, Germany.
Clin Nephrol. 2000 Feb;53(1 Suppl):S2-8.
Normochromic normocytic anemia regularly develops in chronic renal failure when the glomerular filtration rate drops below 20-30 ml/min. The reasons include: 1) a moderately reduced red cell life span, 2) blood loss, and 3) an inadequate increase in erythropoiesis relative to the fall in hemoglobin (Hb). The life-span of red blood cells may be shortened by their reduced resistance to mechanical, osmotic or oxidative stress, as well as by extracorpuscular factors. Blood loss results from dialysis, diagnostic sampling and, in particular, occult gastrointestinal bleeding. The predominant cause of inadequate erythropoiesis is a failure to increase erythropoietin (EPO) production in response to the developing anemia. Experience with recombinant EPO has shown that relative EPO deficiency is the key cause of the anemia and that the response of hematopoietic progenitor cells is not usually diminished in renal failure. However, reduced iron availability, inadequate dialysis, infection and hyperparathyroidism can all impair the efficacy of EPO. Therapeutic use of EPO has also shown clearly for the first time that anemia is responsible for a significant proportion of morbidity in patients with chronic renal failure and probably also contributes to increased mortality through its cardiovascular complications.
当肾小球滤过率降至20 - 30毫升/分钟以下时，慢性肾衰竭患者常出现正色素正细胞性贫血。其原因包括：1）红细胞寿命适度缩短；2）失血；3）相对于血红蛋白（Hb）下降，红细胞生成增加不足。红细胞对机械、渗透或氧化应激的抵抗力降低以及细胞外因素可能会缩短红细胞的寿命。失血源于透析、诊断性采样，尤其是隐匿性胃肠道出血。红细胞生成不足的主要原因是未能随着贫血的发展增加促红细胞生成素（EPO）的产生。重组EPO的应用经验表明，相对EPO缺乏是贫血的关键原因，并且在肾衰竭中造血祖细胞的反应通常不会减弱。然而，铁供应减少、透析不充分、感染和甲状旁腺功能亢进都会损害EPO的疗效。EPO的治疗应用也首次清楚地表明，贫血是慢性肾衰竭患者相当一部分发病率的原因，并且可能还通过其心血管并发症导致死亡率增加。
