Erythropoietic Activity Research Articles

Increased CD177 (PRV1) expression in thalassaemia and the underlying erythropoietic activity

CD177 (PRV1) expression is strongly related to polycythaemia vera (PV). Whilst studying CD177 expression in PV patients and controls, individuals with beta-thalassaemia minor were found to display an elevated expression of CD177. The study was expanded to include patients with thalassaemia intermedia, sickle cell/beta-thalassaemia and thalassaemia major. CD177 expression was increased in these thalassaemic groups and correlated with their erythropoietic activity, as assessed by the measurement of serum erythropoietin and soluble transferrin receptor levels. Within this context, elevated CD177 expression is not only a specific feature of PV but may be an indicator of increased erythropoietic activity in thalassaemia syndromes.

Soluble transferrin receptor and sTfR-F index for assessing concurrent iron deficiency in patients with chronic renal failure

Dear Editor, We read with interest the comments of Dr. Koulaouzidis [1] regarding the results of our study, which was recently reported on the usefulness of the combination index of serum-soluble transferrin receptor (sTfR) and mean corpuscular hemoglobin (MCH) to differentiate coexisting iron deficiency in patients with end-stage renal disease (ESRD) [2]. First, Dr. Koulaouzidis raised a question as to why the sTfR value was used instead of the sTfR-F index (the ratio of sTfR to log ferritin) to evaluate iron deficiency in patients with chronic renal failure. In fact, the sTfR-F index has been suggested as a good estimate of body iron status [3]. Several investigators reported that the sTfR-F index is an additional biochemical marker for identification of irondeficient erythropoiesis [4]. In our study, however, the sTfR-F index was not superior to sTfR value in the correlation coefficients with serum iron (r=−0.22 vs. r=−0.24) and transferrin saturation (r=−0.23 vs. r=−0.27) in the patients with ESRD. The sTfR-F index may reflect the erythropoietic activity, but it seems to depend on the body iron status of subject populations. The relationships between the sTfR-F index and erythropoietic parameters are fairly different from each other between healthy individuals and iron-deficient anemic subjects [5]. In the preliminary test of our study, similar findings were also observed in the patients with rheumatoid arthritis. On the basis of these results, we selected the sTfR value rather than sTfR-F index as an indicator of iron status in the patients with ESRD. Secondly, Dr. Koulaouzidis made a comment on the low cut-off level of sTfR, which was used to diagnose iron deficiency in our study, and emphasized the importance of the normal reference value of sTfR that was obtained from the healthy controls. However, it is likely that there are large differences in sTfR production between healthy subjects and the patients with ESRD, especially under the condition of suppressed erythropoiesis. It is hard to apply the reference intervals of healthy subjects for the patients with chronic renal failure. In our study, mean values of sTfR in the patients with ESRD (1.50±0.97 mg/l) were significantly lower than those in age-matched healthy controls (2.13±0.51 mg/l, p<0.05) [6]. The reason for the low limit of sTfR seems to be that the cut-off point was determined on the basis of the mean sTfR concentrations from the patients with chronic renal failure. Another possible explanation is that the cutoff value of sTfR was defined as a combination index, in conjunction with MCH level in a small number of patients. In healthy subjects, the reference range of serum sTfR concentration shows variances according to investigators. It may reflect the difference of the healthy controls enrolled in the corresponding study. In our experience, fourfold or more Ann Hematol (2008) 87:575–576 DOI 10.1007/s00277-008-0460-5

Continuous Increase in Erythropoietic Activity despite the Improvement in Bone Mineral Density by Zoledronic Acid in Patients with Thalassemia Intermedia-Induced Osteoporosis

Continuous Increase in Erythropoietic Activity despite the Improvement in Bone Mineral Density by Zoledronic Acid in Patients with Thalassemia Intermedia-Induced Osteoporosis

How I transfuse red blood cells and platelets to infants with the anemia and thrombocytopenia of prematurity

Many aspects of hematopoiesis are either incompletely developed in preterm infants or still functioning to serve the fetus (i.e., the intrauterine counterpart to a liveborn preterm neonate). This delayed development and/or slow adaptation to extrauterine life diminishes the capacity of the neonate to produce red blood cells (RBCs), platelets (PLTs), and neutrophils—particularly during the stress of life-threatening illnesses encountered after preterm birth such as sepsis, severe pulmonary dysfunction, necrotizing enterocolitis, and immune cytopenias. The serious medical and/or surgical problems of preterm birth can be further complicated by phlebotomy blood losses, bleeding, hemolysis, and consumptive coagulopathy. To illustrate, some preterm infants, especially those with birth weight less than 1.0 kg and respiratory distress, are given numerous RBC transfusions early in life owing to several interacting factors. Neonates delivered before 28 weeks of gestation (birth weight, <1.0 kg) are born before the bulk of iron transport has occurred from mother to fetus via the placenta and before the onset of marked erythropoietic activity of fetal marrow during the third trimester. Soon after preterm birth, severe respiratory disease can lead to repeated blood sampling for laboratory studies and, consequently, to replacement RBC transfusions. Additionally, preterm infants are unable to mount an effective erythropoietin (EPO) response to decreasing numbers of RBCs, and this factor contributes to the diminished ability to compensate for anemia—thus enhancing need for RBC transfusions. PATHOPHYSIOLOGY OF ANEMIA OF PREMATURITY During the first weeks of life, all infants experience a decline in the number of circulating RBCs. In healthy term infants, the nadir blood hemoglobin (Hb) value rarely decreases to less than 9 g per dL (mean, 11-12 g/dL) at an age of approximately 10 to 12 weeks. 1 Because this postnatal decrease in Hb level is universal and is well tolerated by term infants, it is commonly called the physiologic anemia of infancy. Among preterm infants, this decline occurs at an earlier age and is more pronounced in severity. Mean Hb concentration decreases to approximately 8 g per dL in infants of 1.0 to 1.5 kg birth weight and to 7 g per dL in infants weighing less than 1.0 kg. 2

Subpopulações dos reticulócitos e fração de reticulócitos imaturos como indicadores de aumento da eritropoese em doentes com anemia por deficiência de ferro

O objetivo deste trabalho e o de estudar as subpopulacoes dos reticulocitos e a fracao de reticulocitos imaturos (IFR) enquanto indicadores de atividade eritropoetica em pacientes com anemia por deficiencia de ferro e determinar o seu grau de correlacao com os marcadores tradicionais de deficiencia de ferro. Estudamos um total de 96 individuos, com idades compreendidas entre os 20 e os 86 anos, divididos em dois grupos: individuos controle (n=30) e individuos com anemia por deficiencia de ferro (n=66). A todos eles foi efetuado hemograma completo, incluindo contagem de reticulocitos e os seus indices de maturacao, ferro, transferrina, ferritina e capacidade total de fixacao do ferro. Os individuos com anemia por deficiencia de ferro mostraram um aumento da proporcao de IFR quando comparados com o grupo controle (15.02 ± 9.70% vs 6.43 ± 3.98%, p<0.01, respectivamente). Em relacao as subpopulacoes dos reticulocitos, no grupo de pacientes encontramos um aumento na proporcao de reticulocitos com valores medios de fluorescencia (12.69 ± 6.69% vs 5.88 ± 3.59%, p<0.01) e na proporcao de reticulocitos com alta fluorescencia (1.45 [0.38-3.10] vs 0.40 [0.00-0.90], p<0.05) e diminuicao na proporcao de reticulocitos com baixa fluorescencia (84.83 ± 9.65% vs 93.57 ± 3.98%, p<0.01). Foi encontrada correlacao, positiva ou negativa, entre os parâmetros de maturacao dos reticulocitos entre si, e destes com o RDW (red cell distribution width). Nao foi encontrada correlacao com os outros indicadores laboratoriais de deficiencia de ferro. Em conclusao, a anemia por deficiencia de ferro esta associada com aumento da proporcao de IFR, refletindo aumento da atividade eritropoetica destes pacientes.

Anemia in -thalassemia patients targets hepatic hepcidin transcript levels independently of iron metabolism genes controlling hepcidin expression

Thalassemia associates anemia and iron overload, two opposite stimuli regulating hepcidin gene expression. We characterized hepatic hepcidin expression in 10 thalassemia major and 13 thalassemia intermedia patients. Hepcidin mRNA levels were decreased in the thalassemia intermedia group which presented both lower hemoglobin and higher plasma soluble transferrin receptor levels. There was no relationship between hepcidin mRNA levels and those of genes controlling iron metabolism, including HFE, hemojuvelin, transferrin receptor-2 and ferroportin. These results underline the role of erythropoietic activity on hepcidin decrease in thalassemic patients and suggest that mRNA modulations of other studied genes do not have a significant impact.

Hepcidin: from discovery to differential diagnosis

Although iron is essential for living organisms to survive, its reactive properties require strict regulation in order to prevent toxic effects. Hepcidin, a liver produced peptide hormone, is thought to be the central regulator of body iron metabolism. Its production is mainly controlled by the erythropoietic activity of the bone-marrow, the amount of circulating and stored body iron, and inflammation. Recent reports, however, provide new hypotheses on how hepcidin might exert its regulatory function. Although hepcidin was first discovered in human urine and serum, most of our understanding of hepcidin regulation and action comes from in vitro and mice studies that often use hepcidin mRNA expression as a read out. The difficulties in carrying out studies in humans have mostly been due to the lack of suitable hepcidin assay. The recent development of assays to measure hepcidin in serum and urine has offered new opportunities to study hepcidin regulation in humans. However, for the moment, only a small number of laboratories are able to perform these assays. The aim of this review is to discuss insights into hepcidin regulation obtained from recent clinical studies in the light of findings from in vitro and mice studies. Ongoing studies in humans should provide us with more information on the etiology of iron metabolism disorders in order to create new therapeutic strategies and improve differential diagnosis protocols for these diseases.

Regulation of hepcidin: Insights from biochemical analyses on human serum samples

Knowledge of hepcidin regulation is foremost gained by in vitro studies. We aimed to translate this knowledge into the human in vivo situation. Therefore, we measured serum markers as transferrin saturation (TS), soluble transferrin receptor (sTfR), and C-reactive protein (CRP) in parallel with hepcidin and prohepcidin in patients with iron metabolism disorders and controls. To assess sTfR as erythropoietic activity-associated factor in hepcidin regulation, we studied its influence on hepcidin expression in HepG2 cells. Results showed that sTfR highly associates with erythropoietic activity that strongly interfered with the iron store regulation of hepcidin. HepG2 expression results display an inverse association between hepcidin and sTfR. Inflammation was strongly related to increased hepcidin levels regardless of the iron store and erythropoietic activity status. In contrast, prohepcidin failed to correlate to any other parameter. In conclusion, these studies verify that previous conclusions based on in vitro studies on hepcidin regulation are also likely to apply to human patients. This is underscored by a simple algorithm, based on parameters reflecting the main regulating pathways, that accurately predict the actual measured hepcidin levels. Future studies are needed to validate the combined utility of this predictive algorithm together with actual measured hepcidin levels in clinical diagnosis.

Two-Stage Pharmacokinetic & Efficacy Study of Lenalidomide Alone or Combined with Recombinant Erythropoietin (EPO) in Lower Risk MDS EPO-Failures [PK-002

Background: Lenalidomide (LEN) is a myelosuppressive immunomodulatory drug that has erythropoietic activity in lower risk MDS patients who failed treatment with rhu-EPO (N Eng J Med 2005; 352:549). We previously reported that LEN acts to relieve suppression of the EPO-receptor signal in MDS erythroid precursors, suggesting that the erythropoietic activity of LEN might be improved by combined treatment with rhu-EPO. To evaluate the potential benefit of the combination and the relationship between LEN pharmacokinetics (PK) and treatment-related cytopenias, we performed a PK and efficacy study using a two step design.Methods: Eligible patients had transfusion-dependent, Low/Int-1 IPSS MDS and documented prior treatment with rhu-EPO (≥40,000 U/wk x 6, or darbepoetin equivalent). In the first phase of the study, patients received LEN monotherapy at a dose of 10mg/d [n=25] or 15 mg/d [n=15]. Single dose [n=12] and steady state [n=24] fasting PK were evaluated on days −7 and +14, respectively in subjects receiving the 10mg LEN dosage. After 16 weeks of monotherapy, erythroid non-responders (NR) and minor (MiE) responders (IWG 2000) were offered Combined Treatment in which epoetin alpha (EPO) was added at a weekly dose of 40,000 units sc for a minimum of 8 weeks. Bone marrow (BM) aspirate & biopsy were repeated within 72H of the first grade 4 cytopenia nadir.Results: Demographics of the 39 patients treated to date include: median age, 73 years; IPSS categories, Low [n=17] and Int-1 [n=22]; deletion 5q, n=7. Among 33 patients that completed 16 weeks of monotherapy, 11 (33%) were erythroid responders [10 mg, 7/22 (32%); 15 mg, 4/11 (36%)] with 9 major [del(5q), n=6] and 2 MiE. Sixteen patients proceeded to the Combination Phase with 4 (25%) achieving an erythroid response (2 major, 2 MiE) [10 mg, 1/10; 15 mg, 3/6]. PK analyses showed no evidence of drug accumulation after 14 days of treatment. LEN AUC was highest in patients with reduced creatinine clearance (CLcr, 30–49 mL/min, n=2: 955±49; vs. CLcr ≥50 mL/min, n=22: 558±166). There was no significant difference in steady state AUC or Cmax in patients experiencing a ≥50% vs. <50% decrease in ANC or platelet count during the first 28 days of treatment. However, mean AUC inversely correlated with the interval to ≥50% reduction in platelet count (ANOVA, P = 0.04). Neutropenia [overall, 28/39 (72%); 10mg, 20/25 (80); 15mg, 8/14 (57%)] and thrombocytopenia [overall, 23/39 (59%); 10mg, 17/25 (68%); 15mg, 6/14 (43%)] were the most common ≥grade 3 adverse events (CTC v.3.0), which were accompanied by no significant change in BM cellularity or myeloid:erythroid ratio in non-del5q patients (n=10; P=0.566).Conclusions: Inter-patient variation in systemic LEN exposure is influenced by renal function and may impact interval to development of dose-limiting cytopenias. LEN has erythropoietic activity in primary EPO-non-responders, which may be improved with the addition of EPO. The clinical benefit of the LEN+EPO combination will be investigated in a phase III intergroup study, E2905, in patients who failed primary EPO treatment or have a poor cytokine response profile.

Serum Level of Hepcidin and Erythropoietic Activity after Hematopoietic Stem Cell Transplantation.

Hepcidin, first identified in human urine as a bactericidal peptide, is now considered a central molecule that regulates iron metabolism. Synthesis of hepcidin is known to be up-regulated by at least two signals: iron signal and interleukin-6 (IL-6) signal. The existence of a third signal, an erythropoiesis-associated pathway, has recently been suggested by several researchers experimenting with a mouse model treated with either chemotherapy or irradiation. However, the finding has not yet been clarified in human clinical settings partly because of difficulty in quantitatively measuring the serum level of hepcidin. Therefore, we monitored and assessed the association between the serum level of hepcidin and erythropoietic activity before and after stem cell transplantation for hematological malignancies, because the conditioning regimen followed by SCT dramatically changes the status of erythropoiesis in patients. The serum level of hepcidin-25 was quantitatively measured using a liquid chromatography tandem mass spectrometry-based assay system with synthetic isotopic hepcidin as an internal control, which made our quantification much more reliable and reproducible with very small intra- and inter-assay CVs. (Intra-assay and inter-assay CVs were <6.7% and <8.8%, respectively.) We also measured serum levels of various iron-related parameters and IL-6 as well as bone morphogenetic protein (BMP)-2 and BMP-4. The level of serum hepcidin-25 at week -1 was high (mean ± SD; 74.9 ± 93.9 ng/ml), compared to that in control sera from 28 healthy volunteers (mean ± SD; 21.9 ± 12.3 ng/ml), and the level further increased and peaked at week+1 after SCT (mean ± SD; 255.9 ± 99.3 ng/ml), possibly due to the high level of IL-6 and suppression of erythropoiesis. The hepcidin level of patients at week+4 with delayed erythropoiesis (reticulocyte count less than 40,000 /μl) was significantly higher (p<0.02) than that in those with rapid erythropoiesis (reticulocyte count more than 80,000 /μl). The result did not change even if cases were limited to those without elevated IL-6 levels to exclude the influence of IL-6 on hepcidin expression. Transferrin saturation increased to almost 100% after conditioning therapy and slowly decreased concurrent with erythroid recovery. In contrast, the serum ferritin level tended to increase even after erythroid engraftment irrespective of serum IL-6 or hepcidin levels and the volume of blood cell transfusions after SCT. The level of serum BMP-2 was significantly elevated at all of these time points after SCT compared to that in control sera from 6 healthy volunteers. Among these findings, the level of serum hepcidin-25 was inversely and precisely correlated with reticulocyte counts during and after SCT, suggesting that serum hepcidin-25 may be a good indicator of erythropoietic activity as well as iron utilization by erythropoiesis. These findings indicated that hepcidin is regulated by erythropoiesis through a putative erythropoiesis-associated factor. High serum hepcidin levels observed in SCT patients might have contributed to the disturbance of iron homeostasis and increased serum ferritin levels. Further investigation is needed to clarify the clinical significance of hepcidin in SCT settings.

Zoledronic Acid Increases Bone Mineral Density in Patients with Thalassemia Intermedia-Induced Osteoporosis Regardless of the Incessant Bone Marrow Expansion.

Osteoporosis represents an important cause of morbidity in adult patients with thalassemia. Its pathogenesis is multifactorial, and includes mainly bone marrow expansion, endocrine dysfunction and iron overload. Patients with thalassaemia intermedia (TI) seem to have a more expanded bone marrow with pressure on cortical bone, which causes pain and bone loss in several cases. The measurement of soluble transferrin receptor (sTfR) and erythropoietin (Epo) in the serum is considered as accurate marker of erythropoietic activity in thalassemia. Bisphosphonates are potent inhibitors of osteoclast activity and have been used for the management of thalassemia-induced osteoporosis. The aim of this study was to evaluate the effect of zoledronic acid, the most potent aminobisphosphonate, on bone mineral density (BMD) of patients with TI and explore possible correlations with bone marrow expansion and erythropoietic activity. Thirty-five patients with TI and osteopenia or osteoporosis (13M/22F, median age 45 years) were evaluated. Twenty-three were randomized to receive zoledronic acid, 4 mg, IV, every 3 months (n=12) or every 6 months (n=11) for one year, while 12 patients received placebo every 3 months. There was no difference in terms of the presence of gonadal dysfunction between the three studied groups. BMD of the lumbar spine (L), femoral neck and forearm was determined in all patients, using DEXA, before and 12 months after treatment. Bone marrow expansion was assessed by the measurement of sTfR and Epo serum levels, using an ELISA methodology (R&D Systems, Minneapolis, MN, USA), before and 12 months post zoledronic acid or placebo administration. In all patients markers of bone remodelling, such as C-telopeptide of collagen type-I (CTX) and bone specific alkaline phosphatase (bALP) were also measured by ELISA (Nordic Bioscience Diagnostics, Herlev, Denmark, and Quidel, San Diego, CA, USA, respectively). Patients were asked to quantify their degree of bone pain on Huskisson's visual analogue scale and the McGill-Melzack scoring system before and 12 months post-therapy. All patients had increased values of sTfR, Epo, CTX, and bALP compared with 40 controls of similar age and gender (p<0.001). Patients who received zoledronic acid showed a significant increase in their L-BMD (p=0.01), which was accompanied by a dramatic reduction in CTX and bALP values ((p<0.001). There was no difference in terms of L-BMD changes between zoledronic acid groups. Placebo group showed an aggravation of L-BMD (p=0.041) and markers of bone remodelling at 12 months. No other changes were observed in the BMD of other sites. Zoledronic acid reduced bone pain, which remained stable in placebo group during the study period. There was only weak correlation between baseline sTfR levels and L-BMD, while there was no correlation between Epo or hemolytic parameters (indirect bilirubin, reticulocytes counts, and LDH) with BMD of all studied sites. Serum sTfR and Epo values showed a significant elevation after 12 months of therapy in all studied groups (p<0.01, p<0.02, and p<0.01, respectively); this elevation was irrespective of the L-BMD changes. This study suggests that the increase of BMD produced by zoledronic acid in TI is irrespective of the continuous increase of bone marrow expansion, which is considered a major cause of bone loss in this hemoglobinopathy.

Erythropoietin Supplementation in Patients with Refractory Anemia and Mild Renal Insufficiency - MDS Meets Renal Anemia.

Introduction Even mild renal dysfunction (e.g. creatinine 100 to 140 μmol/l) can be related to inadequate erythropoietin (EPO) response in patients with refractory anemia and bone marrow features compatible with dysplasia (Korte, Cogliatti et al. 2000). Overall, this seems not an infrequent mechanism (Fehr, Ammann et al. 2004) Therefore, patients with MDS bone marrow morphology and secondary bone marrow dysfunction due to EPO deficiency may be diagnosed as having a myelodysplatic syndrome (refracory anemia [RA] or even refractory anemia with ringed sideroblasts [RARS]).Patients and Methods We performed a single center, prospective, non-randomized pilot study to evaluate the potential benefit of EPO therapy in patients with refractory anemia, mild renal insufficiency and low EPO levels.Eligibility criteria were: hemoglobin (hb) concentrations <110g/l, bone marrow features of RA or RARS (according to FAB classification) normal levels of folate, cobalamin, ferritin, TSH and C-reactive protein, mild renal insufficiency (creatinine of 100 to 180 μmol/l) and EPO < 60 U/ml.Exclusion criteria were: active solid malignant tumors, evidence of chronic inflammatory disease, evidence of hemoglobinopathies or haemolytic anemia. Patients received EPO (epoetin beta, Recormon®) for 6 weeks with the aim to increase the hb concentrations to a steady state level of 120g/l. Epo was started at a fixed dose of 150 U/kg subcutaneously three times per week (tiw) and as soon as an improvement in hemoglobin was seen, the dose was reduced as needed to keep the hemoglobin at 120 g/l. With the targetd hb increase of 10 g/l, an estimated standard deviation of 5 g/l and alpha = 0.05 (power 80%), a statistically significant differences were expected with 4 patients treated.Results 5 patients were included in the study. One had a transient renal insufficiency, with excretory renal function normalizing during the study period, whereas the other four patients had persisting mild renal insufficiency. The patients received 150 U/kg tiw of epoetin beta for the first 4 weeks and all reached the target hb of 120g/l after this time (increase significant, p<0.05). Patents showed significantly (p<0.05) increasing levels of soluble transferrin receptor (sTFR) under EPO therapy.Discussion Our data indicate an excellent response to epoetin beta in patients with signs of myelodysplasia and mild renal insufficiency. The response rate (5/5, 100%) was much higher than described in other low risk MDS patients. Increasing levels of soluble sTfR reflect the improved erythropoietic activity and erythroid maturation. From these results, it can be speculated that anemia in low grade MDS with (even mild) renal insufficiency might in fact include aspects of renal anemia. EPO therapy seems an excellent treatment opportunity in anemic patients with marrow MDS morphology, renal dysfunction and low EPO levels. However, this observation and the question whether at least some of this myelodysplasias are direct consequences of inadequate erythropoietin levels warrant larger studies.

Immunomodulatory Therapy for Myelodysplastic Syndromes

Thalidomide and lenalidomide belong to the proprietary group of immunomodulatory drugs (IMiDs) that display broad biologic and pharmacologic properties. Encouraging results of clinical studies that evaluated the efficacy of thalidomide in patients with myelodysplastic syndromes (MDSs) led to the investigation of its structural analogue, lenalidomide, in patients with lower-risk MDS. The cumulative results of studies that tested lenalidomide in patients with interstitial deletion of chromosome 5q, ie, del(5q), showed a high frequency of both erythroid and cytogenetic responses (approximately 75% of patients), which led to US Food and Drug Administration approval of this agent for this cytogenetically defined MDS subset. A multicenter phase III study (MDS-002) that investigated the frequency of transfusion response in lower-risk non-del(5q) MDS patients showed that lenalidomide had significant erythropoietic activity, albeit less robust in lower-risk MDS without del(5q). These studies established lenalidomide as an active erythropoietic-remitting agent with novel cytogenetic-remitting activity in lower-risk MDS patients who would not otherwise benefit from therapy with erythropoietic growth factors. The National Comprehensive Cancer Network Clinical Practice Guidelines recently added lenalidomide to the therapeutic algorithm for MDS as front-line therapy for lower-risk MDS patients with del(5q) and transfusion-dependent anemia.

Immunomodulatory drugs in the treatment of myelodysplastic syndromes

The aim of this article is to discuss the proposed mechanisms of action, clinical trial data, and clinical implications for use of the immunomodulatory drugs in the treatment of myelodysplastic syndrome. The immunomodulatory drugs are a novel, nonteratogenic class of thalidomide analogues that are more potent and less toxic than the parent compound. Lenalidomide, a second generation immunomodulatory drug, has shown substantial remitting activity in myelodysplastic syndrome that is karyotype-dependent. Its biologic effects include T-cell co-stimulation, promotion of erythropoiesis, angiogenesis inhibition, and modulation of apoptosis. Results from the MDS-003 multicenter deletion 5q registration study show that lenalidomide suppresses the deletion 5q clone, and in higher risk myelodysplastic syndrome patients, may also alter the natural history of disease. Lenalidomide was approved by the US Food and Drug Administration for the treatment of International Prognostic Scoring System low or intermediate-1 risk myelodysplastic syndrome patients with chromosome 5q deletion. The most common adverse events with lenalidomide therapy are neutropenia and thrombocytopenia, the frequency of which is highest in patients with deletion 5q, in whom early clonal suppression is expected. Combination strategies are now in progress, which may improve the therapeutic potential of the immunomodulatory drugs. The immunomodulatory drugs show exciting erythropoietic activity in myelodysplastic syndrome that is karyotype-dependent.

Structure, Production and Function of Erythropoietin: Implications for Therapeutical Use in Cardiovascular Disease

Erythropoietin (EPO) is a 30,400 daltons glycoprotein, consisting of 165 amino acids produced mainly in the kidney and in the liver and regulating erythrocyitosis. It primarily acts on erythroid precursor cell at colony-forming units-erythroid stage inhibiting the apoptosis. EPO binds on a specific membrane receptor thereby activating at least three specific intracellular signaling pathways, such as phosphatidylinositol 3-kinase/ protein kinase B, Ras-mitogen-activated protein kinase and some members of the signal transducers and activators of transcription family. In addition to kidney and liver, EPO mRNA has been detected in other tissues; accordingly EPO receptor has been identified in several type of cells and recent reports have suggested new roles for EPO in non-haematopoietic tissues with a robust evidence for neuroprotective and cardioprotective activity. In different animal models, in vitro, in isolated perfused heart and in vivo, recombinant human erythropoietin protects heart from ischemia reperfusion injury and reduces myocardial damage. EPO tissue protective activity can be separated from erythropoietic activity. Molecules owing the first property but not the second one have been described. In patients with acute myocardial infarction serum EPO level correlates inversely with infarct size. Acute coronary syndrome, extracorporeal circulation and percutaneous coronary intervention are potential fields of application for tissue protective EPO activity to reduce myocardial damage, increase cardiac function ad improve outcome.

Erythropoietin and Treatment of Non-anemic Conditions—Cardiovascular Protection

The well-established physiological function of erythropoietin (EPO) is the induction of erythropoiesis. A growing body of evidence indicates that EPO has tissue-protective effects and prevents tissue damage during ischemia and inflammation. Tissue protection after ischemia and injury has been found in the brain, heart, and kidney. It has been speculated that EPO has anti-apoptotic effects in cardiovascular cells. These novel effects of EPO seem to be independent of its erythropoietic activity. Unclear is the role of the known EPO receptor or whether other signaling pathways are involved; a novel EPO receptor might be involved in tissue protection by this hormone. This review article summarizes present knowledge of cardiovascular and renal protective effects of EPO and discusses possible underlying mechanisms.

Correlation between serum transferrin receptor and percentage of parasitemia in malaria. A preliminary report

The serum transferrin receptor (sTfR) concentration is an individual reflects of the extent of erythropoietic activity, and is a useful marker for monitoring erythropoiesis. Malaria is an important tropical disease with evidence of ineffective erythropoiesis. Although there have been previous reports concerning sTfR changes in malaria, these were descriptive studies of infected and non-infected case and there are no previous reports of correlation between sTfR levels and parasitemia in malaria. We performed an animal experiment to study the chronological changes in the level of serum transferrin receptor during infection with Plasmodium gallinaceum. The average level of sTfR in experimental chickens was 6.59 +/- 11.29 mg/L. The average percentage of parasitemia was 3.4 +/- 3.5 % (range 2 to 13 %). According to this study, there is significant correlation between both parameters (r = 0.921; p < 0.05).

Erroneously elevated immature reticulocyte counts in leukemic patients determined using a Sysmex XE-2100 hematology analyzer

The immature reticulocyte fraction (IRF) in peripheral blood, as determined by automated reticulocyte analysis, is calculated using the sum of medium and highly fluorescent reticulocyte numbers and provides information about erythropoietic activity in bone marrow. The purpose of this study was to investigate erroneously elevated IRF in leukemic patients, as determined using a Sysmex XE-2100 hematology analyzer (Sysmex, Kobe, Japan). Normal reticulocyte scattergram patterns show regions corresponding to reticulocytes located between matured RBCs and an upper particle (UPP) region, which show a continuum of non-separated fraction. The UPP represents erythroblasts and some immature reticulocytes. As a control group, peripheral blood was taken from patients with benign hematologic diseases, and their reticulocyte scattergrams all showed a normal pattern; UPP values were all less than 100. However, the reticulocyte scattergrams of 5 of 11 leukemia patients showed abnormal patterns and displayed a gap between RBC and reticulocyte regions. Three patients showed a flag with a message such as "RET Abn Scattergram". IRF results were elevated in these five patients, and their UPP values were above 100. For the remaining six leukemia patients with a normal reticulocyte scattergram pattern, immature reticulocytes were not markedly increased, and UPP values were less than 100. The findings of the present study demonstrate that IRF results may be erroneously elevated in leukemia patients and indicate that hematologists should examine reticulocyte scattergrams and UPP values carefully.

Liver iron concentrations and urinary hepcidin in -thalassemia

Patients with beta-thalassemia, like those with genetic hemochromatosis, develop iron overload due to increased iron absorption, and their iron burden is further exacerbated by transfusion therapy. Hepcidin, a hepatic hormone, regulates systemic iron homeostasis by inhibiting the absorption of iron from the diet and the recycling of iron by macrophages. In turn, hepcidin release is increased by iron loading and inhibited by erythropoietic activity. Hepcidin deficiency is the cause of iron overload in most forms of hereditary hemochromatosis. We sought to determine hepcidin's role in the pathogenesis of iron overload in b-thalassemia. We assessed the degree of iron overload in thalassemia intermedia and major patients by measuring hepatic iron concentration in liver biopsy samples and serum ferritin, estimated erythropoietic drive by assaying soluble transferrin receptor and serum erythropoietin levels and correlated these with urinary hepcidin measurements. Urinary hepcidin levels in beta-thalassemia demonstrate severe hepcidin deficiency in thalassemia intermedia. There was a strong inverse relationship between urinary hepcidin levels and both erythropoietin and soluble transferrin receptor, markers of erythropoietic activity. In contrast, hepcidin levels were elevated in thalassemia major, presumably due to transfusions that reduce erythropoietic drive and deliver a large iron load. Despite similar liver iron concentrations in the two conditions, serum ferritin was much lower in thalassemia intermedia. In thalassemia intermedia, high erythropoietic drive causes severe hepcidin deficiency. The lack of hepcidin results in hyperabsorption of dietary iron, but also in iron depletion of macrophages, lowering their secretion of ferritin and, consequently, serum ferritin levels. In contrast, in thalassemia major, transfusions decrease erythropoietic drive and increase the iron load, resulting in relatively higher hepcidin levels. In the presence of higher hepcidin levels, dietary iron absorption is moderated and macrophages retain iron, contributing to higher serum ferritin. In the future, hepcidin measurements may allow a more accurate assessment of the degree of iron overload and the maldistribution of iron in thalassemia.

Mechanisms of regulation of hemopoiesis during experimental cytostatic myelosuppression induced by carboplatin

The mechanisms of suppression and recovery of the bone marrow erythroid stem were studied on the model of myelosuppression induced by administration of carboplatin in the maximum tolerated dose. Single administration of the cytostatic led to the development of long-term hypoplasia of hemopoiesis. Despite enhanced proliferation of erythroid precursor caused by increased erythropoietic activity of blood plasma and bone marrow cells, inhibition of cell maturation prevented recovery of the content of morphologically recognizable erythrokaryocytes in the bone marrow.