losartan-potassium and Nephrosclerosis

CKD progresses with fibrosis and erythropoietin (Epo)-dependent anemia, leading to increased cardiovascular complications, but the mechanisms linking Epo-dependent anemia and fibrosis remain unclear. Here, we show that the cellular phenotype of renal Epo-producing cells (REPs) alternates between a physiologic Epo-producing state and a pathologic fibrogenic state in response to microenvironmental signals. In a novel mouse model, unilateral ureteral obstruction-induced inflammatory milieu activated NFκB and Smad signaling pathways in REPs, rapidly repressed the Epo-producing potential of REPs, and led to myofibroblast transformation of these cells. Moreover, we developed a unique Cre-based cell-fate tracing method that marked current and/or previous Epo-producing cells and revealed that the majority of myofibroblasts are derived from REPs. Genetic induction of NFκB activity selectively in REPs resulted in myofibroblastic transformation, indicating that NFκB signaling elicits a phenotypic switch. Reversing the unilateral ureteral obstruction-induced inflammatory microenvironment restored the Epo-producing potential and the physiologic phenotype of REPs. This phenotypic reversion was accelerated by anti-inflammatory therapy. These findings demonstrate that REPs possess cellular plasticity, and suggest that the phenotypic transition of REPs to myofibroblasts, modulated by inflammatory molecules, underlies the connection between anemia and renal fibrosis in CKD.

Topics: Anemia; Animals; DNA Modification Methylases; Erythropoietin; Kidney; Mice; Mice, Knockout; Myofibroblasts; Nephrosclerosis; NF-kappa B; Phenotype; Renal Insufficiency, Chronic; Ureteral Obstruction

Topics: Animals; Erythropoietin; Nephrosclerosis; Renal Insufficiency, Chronic

The porphyrias are inherited or acquired metabolic disorders caused by a partial deficiency in one of the enzymes of the heme biosynthetic pathway. Eight enzymes are utilized in the synthesis of heme. An enzyme defect in one of the last seven enzymes will result in one of the seven different forms of porphyria, some of which have similar signs and symptoms. This article describes six diabetic, azotemic patients with no prior history of porphyria, who developed a syndrome similar to acute intermittent porphyria after initiation of treatment with erythropoietin. One of the patients developed the syndrome predialysis, whereas the remaining patients were on maintenance hemodialysis. The symptoms varied but all resolved when erythropoietin was discontinued and reappeared in four cases when erythropoietin was restarted. In all of the patients, the enzyme aminolevulinic acid-dehydratase (ALA-D) was low and the uroporphyrinogen synthase was normal. This enzyme abnormality suggests an acquired form of delta-aminolevulinic acid dehydratase porphyria (ADP). Lead toxicity, succinylacetone, and zinc deficiency are known to depress ALA-D, but these conditions were not present. The development of the acute porphyria syndrome while the patients were receiving pharmacological doses of erythropoietin, which resolved when the drug was stopped, suggests that by stimulating heme synthesis, erythropoietin may unmask an enzyme deficiency resulting in the clinical expression of ADP. The patients responded favorably to a regimen that included discontinuation of erythropoietin, tight blood sugar control, maintaining the hematocrit above 30%, and a KT/V, a measure of dialysis adequacy, of 1.5 in the hemodialysis group. Plasmapheresis accelerated the recovery when used in two patients.

Topics: Adult; Aged; Diabetic Nephropathies; Erythropoietin; Female; Humans; Male; Middle Aged; Nephrosclerosis; Plasmapheresis; Porphobilinogen Synthase; Porphyria, Erythropoietic; Renal Dialysis

Pure red cell aplasia (PRCA) is a rare, but important, complication of erythropoietin (EPO) replacement therapy in patients with renal disease. There is no consensus about the best way to treat this condition; however, recent reports indicated that immunosuppressive therapy is beneficial. We report a patient with EPO-induced PRCA treated with a regimen initially designed for antifactor VIII antibodies in patients with hemophilia. This regimen consists of immunoadsorption therapy using protein A columns, followed by oral prednisolone and single bolus infusions of intravenous immunoglobulin G and cyclophosphamide. Shortly after the course, a swift and rapid increase in reticulocyte count was evident; the patient became transfusion independent and has remained so during 2 years of follow-up. By means of this report, we wish to encourage others to consider this option when first-line treatments fail.

Topics: Anemia; Blood Transfusion; Cyclophosphamide; Drug Therapy, Combination; Epoetin Alfa; Erythropoietin; Humans; Immunoglobulins, Intravenous; Immunosuppressive Agents; Kidney Transplantation; Male; Middle Aged; Nephrosclerosis; Peritoneal Dialysis; Prednisolone; Recombinant Proteins; Red-Cell Aplasia, Pure; Remission Induction; Reticulocyte Count; Sorption Detoxification; Staphylococcal Protein A