The reason of kidney failure anemia is?

(1) erythropoietin (EPR) and reduce the relative lack of receptors. EPR is a by nephritic proximal tubule cells near the synthesis glycoprotein, belongs to the growth factor, in the bone marrow, EPR in red is combined and activate the progenitor cells of the special receptors, the precursor of directional develop into mature red blood cells, when lack of EPR, red is degraded before somatic cell death I receptor lack, also cannot develop into red blood cells, blood oxygen partial pressure influence by the quantity EPR, anemia in patients with chronic renal failure, the stimulation of anemia don't produce enough of the EPR, relative lack of EPR.
(2) the red blood cell growth inhibitory factor. Patients with chronic renal failure in plasma the existence of bone marrow hematopoietic system function inhibition has the material, but on the understanding of the nature of the material is not very clear.
(3) the red blood cells shorten life. Patients with chronic renal failure of red blood cell life is normal 1/2, shorten is the main reason of the hemolysis, but due to the marrow of red blood cell growth, it can make up, it is not the main cause hemolytic anemia reasons.
(4) other and iron use obstacles, nutrients such as protein, iron, folic acid, insufficient hematopoietic raw material, may increase anemia.