Epo Deficiency Research Articles

Iron deficiency in chronic kidney disease and the new generation of intravenous iron

Anemia is the most common complication of chronic kidney disease (CKD) and the main cause of poor prognosis in CKD patients. Iron deficiency (ID) is the second most important factor in the occurrence of anemia in CKD besides EPO deficiency, and iron is currently the main treatment for iron deficiency in patients with CKD anemia. Iron supplements are divided into intravenous iron and oral iron supplements. Oral iron is often ineffective due to its gastrointestinal side effects and low absorption efficiency. Traditional intravenous iron can only be administered in small single doses due to safety restrictions. New intravenous iron agents have emerged. This article provides a brief overview of current iron metabolism in chronic kidney disease, causes of iron deficiency, iron status and new intravenous iron agents available.

The Conundrum of Managing Anemia in Chronic Kidney Disease Patients on Dialysis with Associated Hemoglobinopathies- Perspective from a Single Nephrology Centre in North –Eastern India

Anemia is a common complication in chronic kidney disease (CKD) and has been associated with a reduced quality of life [1] as well as worse survival [2] and increased morbidity and mortality [3]. The prevalence of anemia is more severe as the estimated glomerular filtration rate (eGFR) declines and is 8.4% at stage 1 to 53.4% at stage 5. Similar data is observed in a more recent paper by the CKD Prognosis Consortium which also observed an increased prevalence of anemia among diabetic patients, independent of eGFR and albuminuria [4]. In CKD patients, EPO deficiency starts early in the course of CKD and appears initially, when eGFR falls below 30ml/min/1.73m2, this deficiency becomes more severe [5]. This absolute EPO deficiency can be caused by a decrease EPO production and /or errors in EPO sensing. CKD produces an alteration in oxygen delivery to the kidneys and results in adaptation of renal tissue to consume less oxygen and subsequent maintenance of normal tissue oxygen gradient. As a consequence, prolyl-hydroxylase domain (PHD) enzymes which regulates HIF activity remain active, the HIF heterodimer is not formed and the EPO gene is not activated [6]. Some CKD patients may also present with a functional EPO deficiency or EPO resistance, where normal range. EPO levels co-exist with low hemoglobin levels indicating a blunted bone marrow response to endogenous and exogenous EPO. Mechanisms hypothesized for EPO resistance include presence of pro-inflammatory cytokines thought to induce apoptosis and down regulation of expression of EPO receptor.

In Transgenic Erythropoietin Deficient Mice, an Increase in Respiratory Response to Hypercapnia Parallels Abnormal Distribution of CO2/H+-Activated Cells in the Medulla Oblongata.

Erythropoietin (Epo) and its receptor are expressed in central respiratory areas. We hypothesized that chronic Epo deficiency alters functioning of central respiratory areas and thus the respiratory adaptation to hypercapnia. The hypercapnic ventilatory response (HcVR) was evaluated by whole body plethysmography in wild type (WT) and Epo deficient (Epo-TAgh) adult male mice under 4%CO2. Epo-TAgh mice showed a larger HcVR than WT mice because of an increase in both respiratory frequency and tidal volume, whereas WT mice only increased their tidal volume. A functional histological approach revealed changes in CO2/H+-activated cells between Epo-TAgh and WT mice. First, Epo-TAgh mice showed a smaller increase under hypercapnia in c-FOS-positive number of cells in the retrotrapezoid nucleus/parafacial respiratory group than WT, and this, independently of changes in the number of PHOX2B-expressing cells. Second, we did not observe in Epo-TAgh mice the hypercapnic increase in c-FOS-positive number of cells in the nucleus of the solitary tract present in WT mice. Finally, whereas hypercapnia did not induce an increase in the c-FOS-positive number of cells in medullary raphe nuclei in WT mice, chronic Epo deficiency leads to raphe pallidus and magnus nuclei activation by hyperacpnia, with a significant part of c-FOS positive cells displaying an immunoreactivity for serotonin in the raphe pallidus nucleus. All of these results suggest that chronic Epo-deficiency affects both the pattern of ventilatory response to hypercapnia and associated medullary respiratory network at adult stage with an increase in the sensitivity of 5-HT and non-5-HT neurons of the raphe medullary nuclei leading to stimulation of f R for moderate level of CO2.

MO560IS SERUM ERYTHROPOIETIN CORRELATED WITH IRON METABOLISM AND INFLAMMATION IN NON-DIALYSIS CHRONIC KIDNEY DISEASE PATIENTS WITH ANEMIA?

Abstract Background and Aims Both the relative erythropoietin (Epo) deficiency and its relationship with serum hemoglobin (Hb) are widely postulated in chronic kidney disease (CKD), but the influence of chronic inflammation and iron status on serum Epo levels is still a matter of debate, with yet divergent reported results. Therefore, we aimed to assess the determinants of serum Epo in non-dialysis CKD patients. Method Fifty-two adults with CKD and anemia (defined as Hb <12g/dL), in stable clinical condition, never treated with erythropoiesis-stimulating agents (ESA) entered this cross-sectional, single-center study. Diabetes mellitus, active infectious and inflammatory diseases, malignancy, anemia of other causes than CKD, current immunosuppressive therapy, iron supplementation and blood transfusions in the previous six months were exclusion criteria. The subjects were mostly men (56%), elderly (two thirds over 60 years), with advanced CKD [71% in CKD stages G4-G5, median estimated glomerular filtration rate – eGFR 14.5 (95%CI 16 to 25) mL/min], moderate anemia [Hb 9.8 (95%CI 9.2 to 9.9) g/dL], and mild to moderate inflammation [C-reactive protein 6 (95%CI 9.2 to 18.4) mg/L]. Serum Epo was assessed by ELISA (Abcam® 119522). Complete blood count, reticulocyte index, peripheral blood smear, bone marrow aspiration (Perls’ stain), serum ferritin, and transferrin saturation, were used to investigate anemia and iron metabolism. Parameters of kidney disease (CKD etiology, eGFR and proteinuria), demographic data (age, gender), C-reactive protein, serum albumin, and serum hepcidin-25 (Hep-25, Bachem® commercial ELISA kit) were also analyzed. Results The median serum Epo of the whole cohort was 4.8 (95%CI 5.1 to 9.9) mU/mL. According to median Epo, subjects were clustered in Group 1 (below median, G1) and Group 2 (above median, G2). Estimated GFR and serum Hep-25 were lower in G1 than in G2 [10.6 (95%CI 9.7 to 20.8) vs. 26 (95%CI 19.1 to 32.8) mL/min, p=0.004, and 62.6 (95%CI 51.0 to 85.1) vs. 95.4 (95%CI 77.0 to 108.5) ng/mL, p=0.03, respectively]. All the other investigated parameters were similar in the two groups. In bivariate analysis (Spearman rank correlation), serum Epo was positively associated only with eGFR (rs=0.40, p=0.003). Marginal associations with the percentage of bone marrow sideroblasts, as marker of the iron available for erythropoiesis (rs=0.25, p=0.08), erythrocyte mean corpuscular hemoglobin concentration (rs=−0.26, p=0.07), and reticulocyte index (rs=0.24, p=0.09) were observed. Conversely, serum Epo was not related to hemoglobin, indices of iron stores (e.g. serum ferritin and iron content in bone marrow macrophages), inflammation and nutritional status (e.g. C-reactive protein and serum albumin). In a model of multiple linear regression which explained 14% of serum Epo variation, eGFR was the only determinant: Beta 0.14 (95%CI 0.05 to 0.23), p=0.004. Also, a binary logistic multiple regression model predicting serum Epo lower or higher than the median retained the eGFR as an independent predictor, while serum hepcidin showed only borderline significance: Conclusion Kidney function is the main determinant of endogenous erythropoietin level in moderately anemic patients with advanced CKD, ESA or iron naive, while serum hepcidin-25 seems to exert a limited influence.

POS-261 ROLE OF RETICULOCYTE HAEMOGLOBIN EQUIVALENT(RET HE) IN ASSESSING IRON DEFICIENCY ANAEMIA (IDA) AND FUNCTIONAL IRON DEFICIENCY(FID) IN PATIENTS OF CHRONIC KIDNEY DISEASE

Anemia is most commonly associated feature in patients of CKD. Knowledge about the status of the iron stores, circulating iron and erythropoietin levels are important to diagnose the cause and treat anemia in patients of CKD. Ferritin is an acute phase reactant and can be falsely raised in patients of CKD. Similarly, transferrin may be falsely decreased, TIBC and TSAT may be falsely normal because of chronic disease. Hence, they cannot be relied upon. To find out the exact status of iron stores in the body and the cause of anemia in CKD, patients have to undergo investigations including iron studies, serum EPO, hepcidin levels and bone marrow perl’s staining which is quite expensive and is not routinely available IDA is diagnosed by low iron and normal EPO. FID is characterized by normal iron and EPO. Whereas EPO deficiency is characterized by normal iron and decreased EPO. This study was carried out to correlate the levels of novel marker Ret HE, serum iron profile with iron reserves. In addition, we looked at the efficacy of Ret HE in determining the cause of anemia and its utility in differentiating IDA/FID from anaemia due to EPO deficiency in patients of CKD. Ret HE is widely available, cheap and cost-effective investigation. Prospective, observational study, total of 66 patients were included. All adults diagnosed as CKD and having anaemia were included in the study. Patients were excluded if they denied consent, were diagnosed with hemoglobinopathies, hematological malignancies, hemolytic anemias, or if they had received IV iron therapy within last 6 months. Demographic data, history, physical examination, the type of management was noted and the data compiled. Bone marrow iron stores was taken as the gold standard to diagnose iron deficiency. Bone marrow iron stores was compared to the biochemical iron profile and Ret HE and the comparison between the three was made. Total of 76 (39M and 37F) patients with CKD and anaemia were included. In 10 patients bone marrow was not available hence were excluded in analysis. Out of 66 patients 15 patients had IDA, 19 had EPO deficiency and 35 had FID. Three patients had both IDA and EPO deficiency. Sensitivity and specificity of the parameters is summarized below. Ret HE was most sensitive (85.7%) for diagnosing IDA at a cut off of 27.2pg. Serum ferritin was most specific (87%) for diagnosing IDA at a cut off value of 100mcg/dl. The sensitivity and specificity of RetHE for diagnosing anaemia due to decreased available iron (IDA/FID) was highest i.e. 80% and 50% respectively at a cut off value of 27.2pg. The study results suggest low sensitivity and specificity of serum iron and TSAT in diagnosing IDA and FID and low sensitivity of serum ferritin in diagnosis IDA2. RetHE is the most sensitive marker for diagnosing both iron deficiency and functional iron deficiency is patients of CKD. 3. As RetHe cannot differentiate between IDA and FID so it should be used along with serum ferritin to diagnose the cause of anaemia in CKD patients. 4. We suggest the following to diagnose the cause of anaemia in CKD Ret HE FerritinIDA <27.2 pg <100mcg/dlFID <27.2pg >100mcg/dlEPO deficiency >27.2pg >100mcg/dl 5. Ret HE is cheap and cost-effective investigation in low income countries to diagnose iron deficiency

The correlation between creatinine serum with total iron binding capacity (TIBC) on patients with sufferers chronic renal disease in Gambiran regional public hospital Kediri city

Chronic kidney disease (CKD) is kidney damage that occurs for more than 3 months with a glomerular filtration rate of less than 60 ml/sec/ 1.73 m2. WHO estimates that in Indonesia, there will be an increase in PGK in 1995-2025 by 41.4%. Over the past 40 years, Creatinine serum has become the most common and cheap serum marker for kidney function. One of the most common complications in patients with PGK is anemia. Anemia in PGK can be caused by several factors such as EPO deficiency, iron deficiency, etc. One of the usual parameters checking is the iron status of TIBC. This study aims to determine the relationship of serum Creatinine level with TIBC in chronic kidney patients in Gambiran regional public hospital Kediri and sampling taken by quota sampling. The study used cross-sectional using Rank Spearman statistic test. This test is used for abnormally distributed data types. The measured variable was serum Creatinine level with TIBC. The results of this study indicate that the value of p = (0.000)&gt; α = (0.05), so H1 rejected and H0 accepted, then there is no relationship between serum Creatinine levels with TIBC in patients with chronic kidney disease in Gambiran Hospital Kediri.

Iron attenuates erythropoietin production by decreasing hypoxia-inducible transcription factor 2α concentrations in renal interstitial fibroblasts

Iron is an essential mineral for oxygen delivery and for a variety of enzymatic activities, but excessive iron results in oxidative cytotoxicity. Because iron is primarily used in red blood cells, defective erythropoiesis caused by loss of the erythroid growth factor erythropoietin (Epo) elevates iron storage levels in serum and tissues. Here, we investigated the effects of iron in a mouse model of Epo-deficiency anemia, in which serum iron concentration was significantly elevated. We found that intraperitoneal injection of iron-dextran caused severe iron deposition in renal interstitial fibroblasts, the site of Epo production. Iron overload induced by either intraperitoneal injection or feeding decreased activity of endogenous Epo gene expression by reducing levels of hypoxia-inducible transcription factor 2α (HIF2α), the major transcriptional activator of the Epo gene. Administration of an iron-deficient diet to the anemic mice reduced serum iron to normal concentration and enhanced the ability of renal Epo production. These results demonstrate that iron overload due to Epo deficiency attenuates endogenous Epo gene expression in the kidneys. Thus, iron suppresses Epo production by reducing HIF2α concentration in renal interstitial fibroblasts.

Increased ventilation in female erythropoietin-deficient mouse line is not progesterone and estrous stage-dependent

Previous studies suggest that chronic erythropoietin (Epo) deficiency in male mice does not alter normoxic/hypoxic ventilation. As effects of Epo are sex specific and as progesterone could be a respiratory stimulant, we evaluated the impact of Epo deficiency and its possible interaction with progesterone in ventilatory control in female mice during estrous cycle phases. Compared to wild type (WT) animals, Epo-TAgh female mice exhibited higher ventilation in hypoxia. However, when data were separated into luteal and follicular phases of the estrous cycle, basal ventilation and hypoxic ventilation were not different in both mice strains. As progesterone is known to be a potent respiratory stimulant, additional experiments were performed to elucidate its role. Interestingly, after mifepristone treatment, HVR was not modified in WT and Epo-TAgh mice, showing that the ventilatory stimulation observed in females was not directly mediated by progesterone. We conclude that Epo-TAgh female mice show no estrous stage-dependent increase of ventilatory control and progesterone independent response to hypoxia.

Treatment with erythropoiesis-stimulating agents in chronic kidney disease patients with cancer

Treatment of anemia remains an important component in the care of patients with nondialysis chronic kidney disease (CKD) and end-stage renal disease (ESRD). Erythropoietin-stimulating agents (ESAs) remains a key anemia treatment strategy in this patient population. However, anemia management in this group can become more complicated by prior or current history of malignancy. There has been a great deal of work both scientifically and in clinical trials in oncology that have revealed certain concerns and risks of ESA use in patients with cancer. In this review, we will bring together knowledge from nephrology and oncology literature to help nephrologists understand the implications for ESA treatment when CKD/ESRD is complicated by cancer. We also suggest an approach to the management of anemia in this patient group with active or previous malignancy.

Epo deficiency alters cardiac adaptation to chronic hypoxia

The involvement of erythropoietin in cardiac adaptation to acute and chronic (CHx) hypoxia was investigated in erythropoietin deficient transgenic (Epo-TAgh) and wild-type (WT) mice. Left (LV) and right ventricular functions were assessed by echocardiography and hemodynamics. HIF-1α, VEGF and Epo pathways were explored through RT-PCR, ELISA, Western blot and immunocytochemistry. Epo gene and protein were expressed in cardiomyocytes of WT mice in normoxia and hypoxia. Increase in blood hemoglobin, angiogenesis and functional cardiac adaptation occurred in CHx in WT mice, allowing a normal oxygen delivery (O2T). Epo deficiency induced LV hypertrophy, increased cardiac output (CO) and angiogenesis, but O2T remained lower than in WT mice. In CHx Epo-TAgh mice, LV hypertrophy, CO and O2T decreased. HIF-1α and Epo receptor pathways were depressed, suggesting that Epo-TAgh mice could not adapt to CHx despite activation of cardioprotective pathways (increased P-STAT-5/STAT-5). HIF/Epo pathway is activated in the heart of WT mice in hypoxia. Chronic hypoxia induced cardiac adaptive responses that were altered with Epo deficiency, failing to maintain oxygen delivery to tissues.

The Effectiveness of Recombinant Human Erythropoietin (EPO) Treatment in a Neonate with Hyporegenerative Anemia Following Rh Isoimmunization in Spite of Normal Serum Epo Level

Postnatal hyporegenerative anemia (PNHA) is characterized by depressed erythropoiesis and low number of erythrocytes. Many mechanisms about PNHA pathogenesis have been implicated: intramedullar hemolysis, bone marrow suppression due to intrauterine transfusions, erythropoetin (Epo) deficiency, erythroid hypoplasia, and erythroid hyporegeneration caused by anti-D antibodies [1–3]. A male baby received intravascular intrauterin transfusions (IIUTs) at the 28th, 29th, 32nd, and 34th gestational weeks and at the 3rd day after delivery due to Rh/Rh isoimmunization. At the 39th day, physical examination revealed paleness and hepatosplenomegaly. Hemoglobin (Hb) was 4.3 g/dL and reticulocytes were 0.6%; leukocytes and thrombocytes were normal. Indirect Coombs test was positive. Liver function and lactate dehydrogenase (LDH) were normal; ferritin was 750 ng/mL. The serologies for viral infections were negative. Bone marrow aspiration revealed erythroid hyperplasia. The patient received packed red blood cells (PRBCs). Hb was 7.6 g/dL and reticulocytes were 0.26% when the patient was readmitted at 50 days old. Occult blood in stool was negative. Other laboratory tests were normal. The patient received PRBCs. The patient was readmitted at 72 days old because of paleness. Hb was 5.4 g/dL and liver function tests increased; LDH was 1447 U/dL. Serum Epo was 220 mIU/mL. The patient received PRBCs. Tocopherol, N-acetylcysteine infusion, and ursodeoxycholic acid were given. Hb decreased to 6.2 g/dL after 5 days following PRBC transfusion. Hyporegenerative anemia was diagnosed and recombinant human erythropoietin (rHuEpo) treatment (200 U/kg thrice a week) was initiated at 88 days old. Liver function tests returned to normal at the 21st day after hospitalization and Nacetylcysteine, tohopherol, and ursodeoxycholic acid were stopped. rHuEpo treatment was stopped at the 47th day of the treatment and his ferritin was 1477 ng/mL and Hb was 11.8 g/dL. At present, the patient is transfusion independent and healthy at 18 months old.

Regulation of erythropoietin production

The hormone erythropoietin (Epo) maintains red blood cell mass by promoting the survival, proliferation and differentiation of erythrocytic progenitors. Circulating Epo originates mainly from fibroblasts in the renal cortex. Epo production is controlled at the transcriptional level. Hypoxia attenuates the inhibition of the Epo promoter by GATA-2. More importantly, hypoxia promotes the availability of heterodimeric (α/β) hypoxia-inducible transcription factors (predominantly HIF-2) which stimulate the Epo enhancer. The HIFs are inactivated in normoxia by enzymatic hydroxylation of their α-subunits. Three HIF-α prolyl hydroxylases (PHD-1, -2 and -3) initiate proteasomal degradation of HIF-α, while an asparaginyl hydroxylase ('factor inhibiting HIF-1', FIH-1) inhibits the transactivation potential. The HIF-α hydroxylases contain Fe(2+) and require 2-oxoglutarate as co-factor. The in vivo response is dynamic, i.e. the concentration of circulating Epo increases initially greatly following an anaemic or hypoxaemic stimulus and then declines despite continued hypoxia. Epo and angiotensin II collaborate in the maintenance of the blood volume. Whether extra-renal sites (brain, skin) modulate renal Epo production is a matter of debate. Epo overproduction results in erythrocytosis. Epo deficiency is the primary cause of the anaemia in chronic kidney disease and a contributing factor in the anaemias of chronic inflammation and cancer. Here, recombinant analogues can substitute for the hormone.

Skeletal muscle intrinsic functional properties are preserved in a model of erythropoietin deficient mice exposed to hypoxia

Erythropoietin (Epo)-induced polycythemia is the main factor of adaptation to hypoxia. In this study, we analysed the effects of Epo deficiency on intrinsic functional properties of slow and fast twitch muscles in a model of erythropoietin deficient mice (Epo-TAg(h)) exposed to hypoxia. We hypothesised that Epo deficiency would be deleterious for skeletal muscle structure and phenotype, which could change its functional properties and alters the adaptive response to ambient hypoxia. Wild-type (WT) and Epo-TAg(h) mice were left in hypobaric chamber at 420 mm Hg pressure for 14 days. Soleus (SOL) and extensor digitorum longus (EDL) were analysed in vitro by mechanical measurements, immunohistological and biochemical analyses. The results were compared to those obtained in corresponding muscles of age-matched normoxic groups. Our data did not show any difference between the groups whatever the Epo deficiency and/or hypoxic conditions for twitch force, tetanic force, fatigue, typology and myosin heavy chain composition. Normoxic Epo-TAg(h) mice exhibit improved capillary-to-fibre ratio compared to WT mice in both SOL and EDL whereas no angiogenic effects of hypoxia or combined Epo-deficiency/hypoxia were observed. These results suggest that skeletal muscles possess a great capacity of adaptation to Epo deficiency. Then Epo deficiency is not a sufficient factor to modify intrinsic functional properties of skeletal muscles.

Epo Is Relevant Neither for Microvascular Formation Nor for the New Formation and Maintenance of Mice Skeletal Muscle Fibres in Both Normoxia and Hypoxia

Erythropoietin (Epo) and vascular growth factor (VEGF) are known to be involved in the regulation of cellular activity when oxygen transport is reduced as in anaemia or hypoxic conditions. Because it has been suggested that Epo could play a role in skeletal muscle development, regeneration, and angiogenesis, we aimed to assess Epo deficiency in both normoxia and hypoxia by using an Epo-deficient transgenic mouse model (Epo-TAgh). Histoimmunology, ELISA and real time RT-PCR did not show any muscle fiber atrophy or accumulation of active HIF-1α but an improvement of microvessel network and an upregulation of VEGFR2 mRNA in Epo-deficient gastrocnemius compared with Wild-Type one. In hypoxia, both models exhibit an upregulation of VEGF120 and VEGFR2 mRNA but no accumulation of Epo protein. EpoR mRNA is not up-regulated in both Epo-deficient and hypoxic gastrocnemius. These results suggest that muscle deconditioning observed in patients suffering from renal failure is not due to Epo deficiency.

Circulating erythropoietin in microalbuminuric type 2 diabetic patients with normal renal function: a pilot study

To verify the hypothesis of an early impairment of erythropoietin (Epo) production and to assess the adequacy of its circulating levels in diabetic nephropathy, we investigated Epo values in 18 microalbuminuric type 2 diabetic patients with normal renal function (7 anaemic and 11 nonanaemic), 24 subjects with uncomplicated iron-deficiency anaemia, and 15 healthy controls comparable for sex and age. Mean±S.D. plasma Epo level was 56.4±12.7 mU/mL in iron-deficient patients and 9.3±2.6 mU/mL in controls. In diabetic groups, mean±S.D. Epo level was 11.38±3.65 mU/mL in nonanaemic and 49.12±6.44 mU/mL in anaemic subjects. No significant difference ( P>.05) in Epo values was found between controls and nonanaemic diabetic patients. Anaemic diabetics and iron-deficient subjects had significantly higher values than the nonanaemic groups ( P>.001). An inverse significant relation between Epo levels and Hb concentration resulted in both anaemic diabetics ( r=−.44, P>.05) and iron-deficient patients ( r=−.61, P=.001). Analysis of covariance ( P>.05) and comparison of the two regression lines ( t=0.4, df=29, P>.05) did not show any significant difference between diabetic patients with anaemia and iron-deficient patients. These results suggest that normochromic anaemia observed in microalbuminuric diabetic patients with normal renal function is not due to Epo deficiency, and circulating levels of this hormone are suitably increased with regard to Hb concentration.

La fuite urinaire d'érythropoïétine : une cause méconnue d'anémie au cours des syndromes néphrotiques

Introduction Nephrotic syndrome (NS) is characterized by an excessive urinary protein excretion. Case record A woman, followed-up for NS, present progressive anemia, with no simple explanation. Plasma EPO is low with significant urinary EPO excretion. Treatment with EPO corrects hemoglobin level. Conclusion EPO deficiency due to excessive urinary excretion is an underestimated cause of anemia during NS.

Cadmium and cisplatin damage erythropoietin-producing proximal renal tubular cells

The concomitant manifestations of proximal renal tubular dysfunction and anemia with erythropoietin (Epo) deficiency observed in chronic cadmium (Cd) intoxication, such as Itai-itai disease, suggest a close local correlation between the Cd-targeted tubular cells and Epo-producing cells in the kidney. Therefore, we investigated the local relationship between hypoxia-induced Epo production and renal tubular injury in rats injected with Cd at 2 mg/kg twice a week for 8 months. Anemia due to insufficient production of Epo was observed in Cd-intoxicated rats. In situ hybridization detected Epo mRNA expression in the proximal renal tubular cells of hypoxic rats without Cd intoxication, and the Cd-intoxicated rats showed atrophy of Epo-expressing renal tubules and replacement of them with fibrotic tissue. A single dose of cisplatin at 8 mg/kg, which can induce clinical manifestations similar to those of Cd including renal tubular damage along with Epo-deficient anemia, resulted in Epo-expressing renal tubule destruction on day 4. These data indicate that Cd and cisplatin would induce anemia through the direct injury of the proximal renal tubular cells that are responsible for Epo production.

Therapeutic effect of recombinant human erythropoietin on anaemia with erythropoietin deficiency in diabetic patients.

The aim of this study was to investigate the therapeutic effect of recombinant human erythropoietin (rHuEpo) on anaemia with erythropoietin deficiency in diabetic patients. Twenty diabetic patients with anaemia and Epo deficiency were enrolled. All patients were treated with rHuEpo (Epokine; 4000 U/day s.c., three times a week) for 8 weeks. The responder group (n = 14) had significant increments in haemoglobin compared with the non-responder group (n = 6) (P < 0.05). No significant differences were found between the responder and non-responder groups in terms of duration of diabetes mellitus, serum creatinine level, 24-h urine albumin excretion rates, frequency of diabetic microangiopathy, or HbA1c. There was no difference between the two groups in terms of serum iron and total iron-binding capacity (TIBC). Serum ferritin level was significantly higher in the responder group than in the non-responder group (240.3 +/- 108.4, 25.8 +/- 3.0 micro g/l, P < 0.05), as was transferrin saturation (32.7 +/- 7.9%, 21.2 +/- 5.3%, P < 0.05). rHuEpo could be useful in the treatment of anaemia with erythropoietin deficiency in diabetic patients, and the degree of iron storage and functional iron deficiency might be the main cause of hyporesponsiveness to rHuEpo.

Anaemia of prematurity: treatment with erythropoietin.

Anemia of prematurity is a hyporegenerative anemia usually appearing after the second week, reaching highest intensity in the second month of life. It's normocytic and normochromic with low reticulocyte count. It has been attributed to EPO deficiency. The low EPO levels detected in premature infants and the proper response to synthetic erythropoietin suggested that EPO administration in premature of < or =32 weeks gestational age could be of benefit trying to maintain or increase the hematocrit levels. Protocols of EPO administration to premature babies should always be considered as EPO+Fe, keeping ferritin levels over 100 ng/ml. Failures to EPO+Fe treatment in very small premature babies, measured as no decrease in the need of blood transfusions, may be due to the amount of blood looses that should be restricted.

THE EFFECT OF DIFFERENT IMMUNOSUPPRESSION THERAPY ON ERYTHROPOIETIN PRODUCTION IN RENAL TRANSPLANTATION

51 Anemia in chronic renal failure is due to erythropoietin (Epo) deficiency that is expected to normalize after successful kidney transplantation. We previously studied 40 children with excellent graft function for 12 months post kidney transplantation and found a mean hematocrit (Hct) -2 SD from the mean for age and sex. Human hepatoma (Hep3B) cells were chosen as a model to study the effect of immunosuppression therapy on Epo production. Cyclosporine(CSA), Azathioprine (AZA), FK506, and Mycophenolate Mofetil (MPM), under 21% O2 and 1% O2 (hypoxic) conditions were tested. Epo levels were measured in mU/mg protein ± SEM and compared to baseline conditions. Both CSA(10µg/mL) and AZA (40µg/mL) inhibited Epo production under 21% O2, (p<.03, p<.002) and hypoxic conditions (p<.02, p<.05) respectively. Increased concentration of CSA and AZA (100µg/mL) resulted in greater inhibition. FK506 (.0001 -1 µM) and MPM(.01-10µM) did not inhibit Epo production. CSA added to high dose AZA or MPM depressed Epo production further than either agents alone in 21% O2(p<.002 and p<.007) and 1% O2 (p<.004 and p<.0001). We then measured Hct %, plasma Epo, and ferritin, in 4 pediatric renal transplant recipients, ages 4-8 years, 3 were on CSA and one on FK506 at 1, 2, 3, 6, 9 months post transplantation. Simultaneous blood trough levels for CSA were done (whole blood TDx), and for FK506 (whole blood MEIA). No acute rejection episodes or blood transfusions occurred in any patient. Mean Hct% for all patients pre transplant, and then at 1, 3, 6, 9 months post transplantation were 36%, 33%, 38%, 37%, and 38%. All patients had adequate ferritin levels (range of 30-167 ng/ml) in the first 6 months post transplantation. Mean serum creatinine at 6 months was 0.65±2 mg/dl. Epo levels were compared to each Hct value according to a Reference Regression Graph. An inverse linear relationship between log Epo levels and Hct (R2 = 0.341, p=.0002) was found that was less steep than for healthy adults, and similar to patients with renal failure. No correlation was found between CSA or FK506 levels and Hct. Conclusion: CSA and AZA suppress in-vitro Epo production while FK506 and MPM appear to have no effect. The Epo levels produced after transplantation is inappropriately low compared to Hct. We speculate that the mild anemia in children post renal transplantation is due to inhibition of renal interstitial Epo production related to immunosuppression therapy, specifically CSA. The effect of FK506 and MFM on Epo production in-vivo needs further study.