Recipient's effects on stored red blood cell performance: the case of uremic plasma.

BACKGROUND: Despite universal administration of erythropoiesis-stimulating agents, patients with end-stage renal disease (ESRD) are at high risk for presenting persistent anemia. Due to ambiguities in optimal hemoglobin targets and evidence of recombinant human erythropoietin (EPO)-related toxicity, an increase in blood transfusions has been observed in chronic renal disease over the past years. The probable effects of uremic plasma on the performance of stored red blood cells (RBCs) after transfusion have not been investigated. STUDY DESIGN AND METHODS: Leukoreduced RBCs after short or long storage in CPD-SAGM (n = 5) were assessed for hemolysis, surface removal signaling, reactive oxygen species (ROS) accumulation, and shape distortions before and after reconstitution with healthy (n = 10) or uremic plasma from ESRD patients (n = 20) for 24 hours at physiologic temperature, by using a previously reported in vitro model of transfusion. RESULTS: Temperature and cell environment shifts from blood bag to plasma independently and in synergy affected the RBC physiology. Outcome measures at transfusion-simulating conditions might not be analogous to timing of storage lesion. The uremic plasma ameliorated the susceptibility of stored RBCs to hemolysis, phosphatidylserine externalization, and ROS generation after stimulation by oxidants, but negatively affected shape homeostasis versus healthy plasma. Creatinine, uric acid, and EPO levels had correlations with the performance of stored RBCs in ESRD plasma. CONCLUSION: Renal insufficiency and EPO supplementation likely affect the recovery of donor RBCs and the reactivity of RBCs after transfusion by exerting both toxic and cytoprotective influences on them. ESRD patients constitute a specific recipient group that deserves further examination.

Short-term effects of hemodiafiltration versus conventional hemodialysis on erythrocyte performance.

Hemodiafiltration (HDF) is a renal replacement therapy that is based on the principles of diffusion and convection for the elimination of uremic toxins. A significant and increasing number of end-stage renal disease (ESRD) patients are treated with HDF, even in the absence of definite and conclusive survival and anemia treatment data. However, its effects on red blood cell (RBC) physiological features have not been examined in depth. In this study, ESRD patients under regular HDF or conventional hemodialysis (cHD) treatment were examined for RBC-related parameters, including anemia, hemolysis, cell shape, redox status, removal signaling, membrane protein composition, and microvesiculation, in repeated paired measurements accomplished before and right after each dialysis session. The HDF group was characterized by better redox potential and suppressed exovesiculation of blood cells compared with the cHD group pre-dialysis. However, HDF was associated with a temporary but acute, oxidative-stress-driven increase in hemolysis, RBC removal signaling, and stomatocytosis, probably associated with the effective clearance of dialyzable natural antioxidant components, including uric acid, from the uremic plasma. The nature of these adverse short-term effects of HDF on post-dialysis plasma and RBCs strongly suggests the use of a parallel antioxidant therapy during the HDF session.

Pathophysiological aspects of red blood cells in end-stage renal disease patients resistant to recombinant human erythropoietin therapy.

OBJECTIVE: Modified, bioreactive red blood cells (RBCs) and RBC-derived microvesicles (MVs) likely contribute to the hematological and cardiovascular complications in end-stage renal disease (ESRD). This study assesses the physiological profile of RBCs in patients with ESRD receiving standard or high doses of recombinant human erythropoietin (rhEPO). METHOD: Blood samples from twenty-eight patients under sustained hemodialysis, responsive, or not to standard rhEPO administration were examined for RBC morphology, fragility, hemolysis, redox status, removal signaling, membrane protein composition, and microvesiculation before and after dialysis. Acute effects of uremic plasma on RBC features were examined in vitro through reconstitution experiments. RESULTS: Overall, the ESRD RBCs were characterized by pathological levels of shape distortions, surface removal signaling, and membrane exovesiculation, but reduced fragility compared to healthy RBCs. Irreversible transformation of RBCs was found to be a function of baseline Hb concentration. The more toxic uremic context in non-responsive patients compared to rhEPO responders was blunted in part by the antioxidant, antihemolytic, and anti-apoptotic effects of high rhEPO doses, and probably, of serum uric acid. A selective lower expression of RBC membrane in complement regulators (CD59, clusterin) and of CD47 "marker-of-self" was detected in non-responders and responders, respectively. Evidence for different short-term dialysis effects and probably for a different erythrocyte vesiculation mechanism in rhEPO responsive compared to non-responsive patients was also revealed. CONCLUSION: Deregulation of RBC homeostasis might involve diverse molecular pathways driving erythrocyte signaling and removal in rhEPO non-responders compared to responsive patients.

Blood modifications associated with end stage renal disease duration, progression and cardiovascular mortality: a 3-year follow-up pilot study.

Chronic kidney disease is a risk factor for cardiovascular mortality. This study uncovers pieces of hematological and erythrocyte protein variability observed in end stage renal disease (ESRD) in relation to disease progression/duration and mortality. Using a variety of experimental approaches, erythropoietin/dialysis-treated patients were compared to healthy individuals and had been followed for 36months. During that period, half of the patients died from cardiovascular diseases. The high levels of uremic toxins in those patients were associated with damaged erythrocytes, bad tolerance and poor response to hemodialysis therapy. The postmortem study revealed significant variation in alkaline phosphatase, duration of dialysis, erythrocyte transformation and intracellular hemoglobin concentration compared to the survived patients. The erythrocyte proteins showed substantial remodeling characteristic of pathologic regulation of cell hydration and susceptibility to the dialysis-induced oxidation defects. According to the follow-up study, duration of hemodialysis was associated with a trend towards increased intracellular hemoglobin concentration, membrane expression of glucose transporter-1 and stomatin as well as lower levels of circulating stomatocytes. The uremic index variation in long survived patients is accurately reflected in plasma and erythrocyte oxidative stress modifications. The ESRD patients exhibit impressive compensatory responses to the chronic challenges of the uremic milieu. BIOLOGICAL SIGNIFICANCE: This study demonstrates novel blood modifications probably associated with the duration of erythropoietin/hemodialysis treatment, disease progression and cardiovascular mortality in end stage renal disease. The observed variability adds new pieces to the erythrocyte pathophysiology puzzle in end stage renal disease and suggests novel hematologic and proteomic factors for consideration in future large scale studies on cardiovascular morbidity and mortality candidate biomarkers in uremic patients.

Oxidative stress-associated shape transformation and membrane proteome remodeling in erythrocytes of end stage renal disease patients on hemodialysis.

This study was designed to evaluate the oxidative stress status of erythrocytes and its association with cellular ultrastructure and membrane proteome modifications in patients with end stage renal disease (ESRD) on hemodialysis (HD). For that purpose, we studied red blood cells' (RBCs) modifications in twelve non-diabetic ESRD patients that were responsive in erythropoietin therapy. Intracellular ROS levels were measured by fluorometry, RBCs ultra-structure was examined by electron microscopy, while the membrane proteome by electrophoresis and immunoblotting. Compared to the healthy subjects, the uremic RBCs exhibited significantly increased ROS accumulation. Dialysis partially ameliorated the basal ROS levels but triggered cellular sensitivity to exogenous oxidative stimuli. Common membrane modifications involved loss, aggregation, fragmentation and carbonylation of critical components as well as over-expression of stress markers. HD significantly contributed to membrane proteome remodeling, especially for aquaporin-1, peroxiredoxin-2 and ubiquitinated proteins. The intracellular redox status and the closely associated membrane modifications seemed to be related to membrane instability, loss of surface area through vesiculation, echinocytosis and stomatocytosis. Our data evinced a network of interactions among the uremic toxins, the RBCs membrane composition and the cellular shape modifications in ESRD, which is developed around a core of oxidative provocations and cellular responses.