Aluminum inhibits hemoglobin synthesis but enhances iron uptake in friend erythroleukemia cells

Aluminum inhibits hemoglobin synthesis but enhances iron uptake in Friend erythroleukemia cells. Aluminum (Al) overload in dialysis patients and experimental animals is associated with the development of anemia. However, the precise mechanisms of erythrocyte Al uptake and toxicity are poorly understood. Al accumulation, hemoglobin (Hb) synthesis and cell growth were evaluated in dimethysulfoxide (DMSO)-induced Friend erythroleukemia cells (FEC), a model system for erythroid differentiation. FEC were grown in media containing either Al citrate, transferrin-aluminum (Tf-Al), Tf or no additions. Al accumulation occurring only in cells grown in Tf-Al containing media was detected at 24 hours and increased linearly up to 96 hours after induction. By 96 hours, 200 ± 36 µg Al/liter lysed cells were detected in Tf-Al grown cells versus 5 ± 1 µg Al/liter lysed cells in cells grown in Al citrate (P < 0.001). Tf-Al inhibited Hb synthesis at 72 hours after induction. At 96 hours 50 ± 15% cells were benzidine positive when grown in Tf-Al compared to 76 ± 15% in Al citrate (P < 0.001). FEC grown in increasing concentrations of Tf-Al (100 to 500 µg/ml) showed inhibition of Hb synthesis at lower concentrations of Tf-Al at 100 µg/ml than for cell growth at 300 µg/ml. Higher concentrations of Tf-Al (>300 µg/ml) did not further inhibit Hb synthesis or cell growth. Iron (Fe) and Tf uptake were increased in Al loaded FEC compared to control cells. The increased Tf uptake was probably the result of increased Tf receptor expression on FEC since Tf cell cycling time was unchanged. These data indicate that Al utilizes the Tf uptake pathway for entry into erythrocyte precursors. Al is toxic at sites distal to Fe uptake, possibly at the heme and/or globin synthetic pathways, resulting in decreased Hb synthesis and cell growth

Thigh Grafts Contribute Significantly to Patients' Time on Dialysis

Background and objectives: Thigh grafts are placed in hemodialysis patients who have exhausted all arm access sites. The goal of this study was to compare the survival, complication rates, and overall contribution of thigh grafts with arm grafts and fistulas in patients with at least one functional thigh graft during their dialysis history

Successful models of interventional nephrology at academic medical centers

The foundation of endovascular procedures by nephrologists was laid in the private practice arena. Because of political issues such as training, credentialing, space and equipment expenses, and co-management concerns surrounding the performance of dialysis-access procedures, the majority of these programs provided care in an outpatient vascular access center. On the basis of the improvement of patient care demonstrated by these centers, several nephrology programs at academic medical centers have also embraced this approach. In addition to providing interventional care on an outpatient basis, academic medical centers have taken a step further to expand collaboration with other specialties with similar expertise (such as with interventional radiologists and cardiologists) to enhance patient care and research. The enthusiastic initiative, cooperative, and mutually collaborative efforts used by academic medical centers have resulted in the successful establishment of interventional nephrology programs. This article describes various models of interventional nephrology programs at academic medical centers across the United States