[The hemodiafiltration with endogenous reinfusion reduces the erythroid progenitor inhibition by uremic serum]. / L'emodiafiltrazione con reinfusione endogena (HFR) riduce l'inibizione dei precursori eritroidi (BFU-E) da siero uremico.

PURPOSE: Anemia in end-stage renal disease (ESRD) patients shows a lower proliferation of erythroid progenitor cells such as burst forming unit-erythroid (BFU-E) than in normal subjects. As on-line hemodiafiltration with endogenous reinfusion(HFR) is thought to have a better biocompatibility and a wide range of uremic toxin removal, we compared the effect of serum obtained pre- and post-standard hemodialysis (HD) and HFR dialysis performed in four ESRD patients with proliferation in normal subject) (controls) bone marrow BFU-E. METHODS: Mononuclear fraction was obtained by Ficoll-Hypaque density centrifugation and studies were performed in three different conditions: standard culture, adding serum from controls, adding serum from ESRD patients pre- and post HD and HFR dialysis. BFU-E were counted after 14 days with an inverted microscope and expressed as average scores from two dishes. Standardization between experiments was checked with a control culture for each experimental culture. RESULTS: The BFU-E proliferation rate was clearly reduced by adding serum from ESRD patients either pre-HD or pre-HFR. However, while this inhibition was exacerbated by post-HD serum, it showed a significant reduction with post-HFR serum. CONCLUSIONS: This effect could be due to the removal of uremic toxins or to a lower dialysis-induced cytokine release, both mechanisms involved in erythropoiesis inhibition in ESRD.

[Increased in vitro and ex vivo proliferation of erythroid precursors induced by calcitriol in chronic renal failure. Synergistic effect with rHuEPO]. / Aumentata proliferazione dei precursori eritroidi indotta in vitro ed ex vivo dal calcitriolo in corso di uremia cronica.Effetto sinergico con rHuEPO.

BACKGROUND: Calcitriol (C) improves anemia in chronic renal failure. This improvement may be related to the suppression of iPTH release, but also to a direct effect on erythropoiesis. MATERIALS AND METHODS: In order to verify this hypothesis, 33 patients with chronic renal failure were enrolled: 24 were undergoing hemodialysis, 9 managed conservatively. All patients were free from other chronic or hematological disease, had a negative DFO test and aluminum levels below 20 mcg/l. iPTH range was 250-480 pg/l. None had yet been treated with C. In vitro study- Samples were drawn for a basal erythroid precursors (Burst Forming Unit-Erythroid BFU-E) study. After mononuclear cells were isolated by centrifugation with Ficoll-Hypaque, they were incubated for 15 days with rHuEPO 3U/ml (A), rHuEPO 3U/l + C 30 pg (B), rHuEPO 3U/ml + C 300 pg (C), rHuEPO 30 U/ml + C 300 pg (D) was performed. Ex vivo study- After the basal evaluation, 10 pts on dialysis were treated with C (Calcijex-Abbott) 1 g three times a week. BFU-E studies were performed after 1,2 and 4 months. RESULTS: In vitro, culture B showed an increased BFU-E proliferation vs A (41+/- 23 vs 27+/-15, p less than 0.02); in C and D cultures proliferation was 61+/-31 and 78+/- 42 respectively, p less than 0.01 vs A. There was no difference among pts with renal failure and pts treated conservatively. During the in vivo study all cultures showed a progressive proliferation increase, without a plateau level (basal, after 1, 2, 4 months respectively): in A: 17+/-8, 22+/-13, 30.9+/-14.9, 41.4+/-20; in B: 27.3+/-15, 35.6+/-20, 45.5+/-21, 57+/-26; in C: 48.2+/-20.6, 63.7+/-32, 75.7+/-37, 83+/-40; in D: 72+/-24, 91+/-42, 106+/-42, 110+/-42.3 (always p less than 0.001). The hematocrit and hemoglobin increase was constant but not significant. The iPTH decrease was not related to BFU-E proliferation. CONCLUSIONS: In chronic uremia C has a direct effect on erythroid precursor proliferation, both in vitro and ex vivo, with a sinergystic effect with rHuEPO. This effect is not related to iPTH suppression. C may be a useful adjuvant therapy for rHuEPO treatment.

[Calcitriol increases burst forming unit-erythroid (BFU-E) in vitro proliferation in chronic uremia. Synergic effect with DNA recombinant erythropoietin (rHu-Epo)]. / Aumentata proliferazione dei precursori eritroidi burst forming unit-erythroid (BFU-E) indotta in vitro dal calcitriolo nell'uremia cronica. Effetto sinergico con l'eritropoietina da DNA ricombinante (rHu-Epo).

BACKGROUND: It has been suggested that calcitriol (C) could improve anemia in chronic renal failure. However it remains debatable whether vitamin D has a specific effect on erythropoiesis, or it acts via suppression of hyperparathyroidism. METHODS: We enrolled 29 patients with chronic renal failure, free from malignancies, iron deficiency or other chronic or hematological diseases. Aluminium accumulation was also excluded by DFO test. 22 were on hemodialysis and 7 on conservative management, creatinine clearance ranging 22-48 ml/min. Their mean age was 62+/-28 years and duration of renal disease was 98+/-51 months. No patient under-went rHu-Epo or Vitamin D treatment. 4 subjects were enrolled as controls. Samples of peripheral blood were drawn for the Burst Forming Unit-Erythroid (BFU-E) assay. After isolation of mononuclear cells by density gradient centrifugation with Fycoll-Hypaque, a 15-day incubation was set up with four different conditions: a) adding standard dose, 3 U/ml, of r-HuEpo (Dompè Biotec), standard colture; b) combined doses of r-HuEpo, 3 U/ml, and C (Abbott), 30 pg; c) standard dose, 3 U/ml, of r-HuEpo and high dose, 300 pg, of C; and lastly d) combined high doses of r-HuEpo, 30 U/ml, and C, 300 pg. RESULTS: In the b colture (combined low doses) a higher BFU-E proliferation was found vs standard (a) colture (33.2+/-15.5 vs 17.1+/-9.2, p<0.02); interestingly, either in the c and d studies BFU-E showed an even higher proliferation (52.3+/-24 and 86.3+/-37.8 respectively, p<0.01 vs a). No difference was found when evaluating separately preterminal and hemodialysis patients. In control subjects only colture d showed an increased BFU-E proliferation. CONCLUSIONS: C has a direct effect on erythroid precursors proliferation in vitro, acting in a sinergystic manner with rHuEpo. C may be useful as adjuvant therapy for renal anemia.