Correlation between Fractional Reabsorption of Sodium and Erythropoietin dose in Peritoneal Dialysis Patients

2006 ◽  
Vol 26 (5) ◽  
pp. 581-586
Author(s):  
Shahrzad Ossareh ◽  
Iloise Moupas ◽  
Elias Thodis ◽  
Dimitrios G. Oreopoulos ◽  
Sandra Donnelly
Keyword(s):  
Peritoneal Dialysis ◽  
Creatinine Clearance ◽  
Negative Correlation ◽  
Transferrin Saturation ◽  
Sodium Reabsorption ◽  
Dialysis Patients ◽  
Renal Oxygen Consumption ◽  
Epo Deficiency ◽  
Renal Oxygen ◽  
Tissue Oxygen Pressure

Background Erythropoietin (EPO) deficiency of chronic renal failure (CRF) may be a functional consequence of decreased glomerular filtration rate and fractional reabsorption of sodium (FRNa). Decreased FRNa reduces renal oxygen consumption and increases tissue oxygen pressure, resulting in less EPO production. We hypothesized that, in CRF patients, there is a positive relationship between EPO production and FRNa and that, in such patients receiving EPO, a negative correlation is expected between FRNa and EPO dose. Methods Creatinine clearance, FRNa, serum iron, transferrin, transferrin saturation, ferritin, and intact parathyroid hormone (iPTH) levels were measured in 91 peritoneal dialysis patients. The correlation between EPO dose and FRNa was studied. Results Mean EPO dose was 7076 ± 4821 units/week and mean FRNa was 93.40% ± 6.14%. A negative correlation was found between EPO dose and FRNa ( r = -0.28, p < 0.01), and a positive correlation was found between both ferritin and iPTH and EPO dose ( r = 0.39, p < 0.001 and r = 0.35, p < 0.002 respectively). After adjusting for the effect of creatinine clearance, ferritin, and iPTH, there was still a significant correlation between EPO dose and FRNa ( p < 0.05). Conclusion In CRF patients there is a negative correlation between FRNa and EPO dose, which supports the hypothesis that EPO deficiency may be related to the decreased renal oxygen-consuming work of sodium reabsorption.

scholarly journals Accounting for oxygen in the renal cortex: a computational study of factors that predispose the cortex to hypoxia

2017 ◽  
Vol 313 (2) ◽  
pp. F218-F236 ◽  
Author(s):  
Chang-Joon Lee ◽  
Bruce S. Gardiner ◽  
Jennifer P. Ngo ◽  
Saptarshi Kar ◽  
Roger G. Evans ◽  
...  
Keyword(s):  
Oxygen Tension ◽  
Renal Cortex ◽  
Computational Study ◽  
Ischemia Reperfusion ◽  
Sodium Reabsorption ◽  
Model Parameters ◽  
Arterial Blood ◽  
Increased Risk ◽  
Renal Oxygen Consumption ◽  
Renal Oxygen

We develop a pseudo-three-dimensional model of oxygen transport for the renal cortex of the rat, incorporating both the axial and radial geometry of the preglomerular circulation and quantitative information regarding the surface areas and transport from the vasculature and renal corpuscles. The computational model was validated by simulating four sets of published experimental studies of renal oxygenation in rats. Under the control conditions, the predicted cortical tissue oxygen tension ([Formula: see text]) or microvascular oxygen tension (µPo2) were within ±1 SE of the mean value observed experimentally. The predicted [Formula: see text] or µPo2 in response to ischemia-reperfusion injury, acute hemodilution, blockade of nitric oxide synthase, or uncoupling mitochondrial respiration, were within ±2 SE observed experimentally. We performed a sensitivity analysis of the key model parameters to assess their individual or combined impact on the predicted [Formula: see text] and µPo2. The model parameters analyzed were as follows: 1) the major determinants of renal oxygen delivery ([Formula: see text]) (arterial blood Po2, hemoglobin concentration, and renal blood flow); 2) the major determinants of renal oxygen consumption (V̇o2) [glomerular filtration rate (GFR) and the efficiency of oxygen utilization for sodium reabsorption (β)]; and 3) peritubular capillary surface area (PCSA). Reductions in PCSA by 50% were found to profoundly increase the sensitivity of [Formula: see text] and µPo2 to the major the determinants of [Formula: see text] and V̇o2. The increasing likelihood of hypoxia with decreasing PCSA provides a potential explanation for the increased risk of acute kidney injury in some experimental animals and for patients with chronic kidney disease.

scholarly journals Anemia in peritoneal dialysis patients

2006 ◽  
Vol 134 (3-4) ◽  
pp. 133-137 ◽  
Author(s):  
Mirjana Lausevic ◽  
Vidosava Nesic ◽  
Natasa Jovanovic ◽  
Biljana Stojimirovic
Keyword(s):  
Peritoneal Dialysis ◽  
Blood Count ◽  
Iron Supplementation ◽  
Transferrin Saturation ◽  
Recombinant Erythropoietin ◽  
Dialysis Patients ◽  
Human Recombinant Erythropoietin ◽  
Iron Stores ◽  
Number Of Patients ◽  
Significant Difference

A normocytic normochromic anemia is one of the first signs of renal failure. Since anemia increases morbidity and mortality, its elimination is one of the essential objectives of the treatment. Human recombinant erythropoietin (rHuEPO) has changed the therapeutical approach to anemia. The aim of the present study was to compare efficacy of anemia correction in peritoneal dialysis patients depending on treatment and dialysis modality. The study is the retrospective analysis of 64 patients who presented to our Clinic in 2003. Eighteen (28.13%) patients were treated with rHuEPO, 14 (28%) underwent continuous ambulatory peritoneal dialysis (CAPD), 2 (100%) - automated peritoneal dialysis (APD) and 2 (33.3%) - intermittent peritoneal dialysis (IPD). Mean hemoglobin level was 98.6?17.82 g/l in patients treated with rHuEPO versus 98.81?15.14 g/I in patients without rHuEPO treatment. Erythropoietin requirements were 3392.85?1211.77 IU/week. AII patients received iron supplementation during rHuEPO therapy. Mean serum ferritin levels were 463.41 ?360 ?g/l. Transferrin saturation (TSAT) was 0.35?0.16%. No difference of serum iron and TSAT levels was found between CAPD and IPD patients. The degree of anemia significantly differed between CAPD and IPD patients. A total of 17.11% of PD patients were given blood transfusions, most frequently during the first three months after the onset of dialysis. Our conclusion is that the number of patients receiving rHuEPO should be increased, as 50% of our patients should be substituted, while only 28% are being treated. As 50% of patients receiving rHuEPO failed to reach target Hgb levels, higher EPO doses should be considered. Iron stores should be continuously monitored, particularly in patients receiving rHuEPO, since iron deficiency is an important problem for patients undergoing peritoneal dialysis, especially during erythropoietin therapy. Oral iron supplementation is satisfactory in the majority of patients, and iron-gluconate is absorbed better than iron-sulphate. If required, intra-venous iron bolus is safe and efficient. Continuous peritoneal dialysis treatment improves blood count more effectively compared to intermittent procedures, as hemoglobin levels are significantly higher in patients with comparable iron stores. Peritoneal dialysis is particularly efficient in improving the blood count in diabetics, since no significant difference of anemia between patients affected by diabetes mellitus and the others could be found in our study.

Risk Factors for Early Mortality in U.S. Peritoneal Dialysis Patients: Impact of Residual Renal Function

2002 ◽  
Vol 22 (3) ◽  
pp. 371-379 ◽  
Author(s):  
◽  
Michael V. Rocco ◽  
Diane L. Frankenfield ◽  
Barbara Prowant ◽  
Pamela Frederick ◽  
...  
Keyword(s):  
Risk Factors ◽  
Blood Pressure ◽  
Renal Function ◽  
Peritoneal Dialysis ◽  
Serum Albumin ◽  
Creatinine Clearance ◽  
Residual Renal Function ◽  
Chronic Peritoneal Dialysis ◽  
Dialysis Patients ◽  
The Mean

Background Potential risk factors for 1-year mortality, including the peritoneal component of dialysis dose, residual renal function, demographic data, hematocrit, serum albumin, dialysate-to-plasma creatinine ratio, and blood pressure, were examined in a national cohort of peritoneal dialysis patients randomly selected for the Centers for Medicare and Medicaid Services End-Stage Renal Disease (ESRD) Core Indicators Project. Methods The study involved retrospective analysis of a cohort of 1219 patients receiving chronic peritoneal dialysis who were alive on December 31, 1996. Results During the 1-year follow-up period, 275 patients were censored and 200 non censored patients died. Among the 763 patients who had at least one calculable adequacy measure, the mean [± standard deviation (SD)] weekly Kt/V urea was 2.16 ± 0.61 and the mean weekly creatinine clearance was 66.1 ± 24.4 L/1.73 m2. Excluding the 365 patients who were anuric, the mean (±SD) urinary weekly Kt/V urea was 0.64 ± 0.52 (median: 0.51) and the mean (±SD) urinary weekly creatinine clearance was 31.0 ± 23.3 L/1.73 m2 (median: 26.3 L/1.73 m2). By Cox proportional hazard modeling, lower quartiles of renal Kt/V urea were predictive of 1-year mortality; lower quartiles of renal creatinine clearance were of borderline significance for predicting 1-year mortality. The dialysate component of neither the weekly creatinine clearance nor the weekly Kt/V urea were predictive of 1-year mortality. Other predictors of 1-year mortality ( p < 0.01) included lower serum albumin level, older age, and the presence of diabetes mellitus as the cause of ESRD, and, for the creatinine clearance model only, lower diastolic blood pressure. Conclusion Residual renal function is an important predictor of 1-year mortality in chronic peritoneal dialysis patients.

Association of Kt/V and Creatinine Clearance With Outcomes in Anuric Peritoneal Dialysis Patients

2008 ◽  
Vol 52 (6) ◽  
pp. 1122-1130 ◽  
Author(s):  
Linda Fried ◽  
Nasser Hebah ◽  
Fredric Finkelstein ◽  
Beth Piraino
Keyword(s):  
Peritoneal Dialysis ◽  
Creatinine Clearance ◽  
Dialysis Patients

scholarly journals Regulation of erythropoietin production is related to proximal tubular function

1989 ◽  
Vol 256 (5) ◽  
pp. F942-F947 ◽  
Author(s):  
K. U. Eckardt ◽  
A. Kurtz ◽  
C. Bauer
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Sensor ◽  
Collecting Duct ◽  
Inhibitory Effect ◽  
Tubular Function ◽  
Sodium Reabsorption ◽  
Renal Oxygen Consumption ◽  
Proximal Tubular ◽  
Proximal Tubular Function ◽  
Renal Oxygen

Regulation of renal erythropoietin (EPO) production is based on an intrarenal oxygen sensor. Whereas the sensitivity of this oxygen sensor to variations in renal oxygen supply is well established, the influence of changes in renal oxygen consumption has not yet been elucidated. Diuretic drugs, which inhibit active sodium reabsorption, reduce tubular oxygen consumption. We therefore investigated the effects of acetazolamide, furosemide, hydrochlorothiazide, and amiloride, known to preferentially inhibit sodium reabsorption at different segments of the nephron, on hypoxia-induced EPO formation in mice. Those drugs that are considered to act mainly in the loop of Henle, distal tubule, and collecting duct (furosemide, hydrochlorothiazide, and amiloride) did not impair EPO formation. Acetazolamide on the other hand, which is thought to act predominantly at the proximal tubular site, significantly reduced EPO formation in response to normobaric hypoxia (8 and 14% O2) and functional anemia (0.1% carbon monoxide). This inhibitory effect of acetazolamide was dose dependent and correlated with the natriuresis induced. It appeared not to depend on the metabolic acidosis induced by the drug, since the simultaneous administration of sodium bicarbonate, which restored standard bicarbonate levels to normal, did not diminish the inhibitory effect of acetazolamide on EPO production. In conclusion the data suggest that the regulation of EPO production is likely to be related to proximal tubular function.

Renal sodium transport and oxygen consumption

1961 ◽  
Vol 201 (3) ◽  
pp. 511-516 ◽  
Author(s):  
Fredrik Kiil ◽  
Knut Aukland ◽  
Harald E. Refsum
Keyword(s):  
Oxygen Consumption ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Sodium Transport ◽  
Filtration Rate ◽  
Sodium Reabsorption ◽  
Renal Oxygen Consumption ◽  
Tubular Lumen ◽  
Oxygen Difference ◽  
Renal Oxygen

Glomerular filtration rate and renal blood flow were increased in dogs by infusion of 2% glycine and hypertonic NaCl at rates of 8 ml/min. This procedure resulted both in an increased rate of sodium reabsorption and in increased oxygen consumption. Approximately six equivalents of sodium were transported per equivalent oxygen consumed, a ratio similar to that obtained by others when glomerular filtration rate had been reduced. These observations strongly suggest that a large part of renal oxygen consumption is related to the transport of sodium. When the rate of sodium reabsorption was reduced during mannitol diuresis, arteriovenous oxygen difference decreased, but renal oxygen consumption remained unchanged. It is suggested that the active sodium transport in the proximal tubules continues at an unchanged rate during mannitol diuresis but that net reabsorption is reduced owing to increased passive influx into the tubular lumen when the transtubular concentration gradient increases. Other interpretations are discussed.

Efficacy of a Low-Dose Intravenous Iron Sucrose Regimen in Peritoneal Dialysis Patients

2002 ◽  
Vol 22 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Elisabeth Dittrich ◽  
Martin Schillinger ◽  
Gere Sunder–Plassmann ◽  
Walter H. Hörl ◽  
Andreas Vychytil
Keyword(s):  
Peritoneal Dialysis ◽  
Iron Deficiency ◽  
Serum Ferritin ◽  
Low Dose ◽  
Transferrin Saturation ◽  
Iron Sucrose ◽  
Dialysis Patients ◽  
Functional Iron Deficiency ◽  
Iv Iron ◽  
Absolute Iron Deficiency

Objective Sufficient iron substitution leads to a decrease in the required recombinant human erythropoietin (rHuEPO) dose and/or an increased hematocrit in dialysis patients. Intravenous (IV) application of larger doses of iron sucrose may be associated with hyperferritinemia, appearance of catalytically free iron, and impaired phagocyte function. Therefore, we investigated the effectiveness of a low-dose IV iron regimen in peritoneal dialysis (PD) patients. Patients and Interventions Forty-five PD patients were followed over a period of 1 year. Serum ferritin, serum transferrin saturation, and hemoglobin were measured monthly. In cases of absolute iron deficiency (serum ferritin < 100 μg/L), 50 mg iron sucrose was given IV every second week. In cases of functional iron deficiency (ferritin ≥ 100 μg/L and transferrin saturation < 20%) and in iron repleted patients (ferritin ≥ 100 μg/L and transferrin saturation ≥ 20%), 50 mg IV iron sucrose was applied monthly. Iron therapy was stopped in cases of acute infection (until complete recovery) and when serum ferritin level was ≥ 600 μg/L. Results To analyze the influence of iron substitution on erythropoiesis and rHuEPO requirements, the EPO resistance index (ERI; quotient of rHuEPO dose in units/kilogram/week and hemoglobin in grams per deciliter) was calculated every 3 months. The ERI decreased significantly during the course of the study in the whole patient group ( p = 0.009) as well as in the subgroup of 21 patients with absolute iron deficiency ( p = 0.01). A nonsignificant decrease in the ERI was observed within the group of 14 iron repleted patients ( p = 0.5). There was no significant change in the ERI in 10 patients with functional iron deficiency ( p = 0.6). Conclusion The low-dose IV iron regimen used in this study substantially decreased rHuEPO requirements in patients with absolute iron deficiency and was effective in maintaining iron stores in iron repleted patients. However, in the absence of significant hyperparathyroidism, aluminum toxicity, or inadequate dialysis, it did not improve the ERI in patients with functional iron deficiency.

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