Changes In Reticulocyte Count Research Articles

#2898 Exposure response model describing hematologic changes with chronic treatment of CKD anemia with vadadustat

Abstract Background and Aims Vadadustat (VADA) is an oral hypoxia-inducible factor (HIF) prolyl hydroxylase inhibitor, a class of drugs that stabilize HIF and stimulate endogenous erythropoietin production, increasing iron mobilization and red blood cell production. VADA is approved in 36 countries globally and is indicated in the European Union for the treatment of symptomatic anaemia associated with chronic kidney disease (CKD) in adults on chronic maintenance dialysis and is an alternative to treatment with erythropoiesis-stimulating agents (ESAs). The aim of this work was to develop a predictive, semi-mechanistic model to understand the effects of VADA and erythropoiesis-stimulating agents (ESAs) on hemoglobin response and to evaluate the impact of intrinsic and extrinsic patient characteristics on that response for non-dialysis dependent (NDD) and dialysis-dependent (DD) patient populations. Method A predictive semi-mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model for VADA and ESA treatment was developed using nonlinear mixed effects methods. The model describes changes in reticulocyte count (RETICs), mature erythrocytes (RBCs) and hemoglobin (Hb) as a function of drug exposure and subject-specific characteristics. The dataset was based on data from 7 Phase 1 to Phase 3 studies (Table 1; N = 894 for VADA; N = 560 for ESA modeling) in healthy volunteers and subjects with NDD- or DD-CKD who were either ESA-naïve or ESA experienced but not receiving treatment at screening. Prior population PK modeling of VADA provided estimated drug exposures for VADA-treated subjects, while dose normalized to standard units (IU/kg/wk) was used as the exposure metric for subjects on ESA. Each of these exposure metrics could vary with time, as the dose was adjusted according to observed Hb response. This work evaluated alternative model structures, as well as covariate effects affecting Hb individual response. Results A predictive semi-mechanistic pharmacokinetic/pharmacodynamic (PK/PD) model for VADA and ESA treatment was developed using nonlinear mixed effects methods. The model describes changes in reticulocyte count (RETICs), mature erythrocytes (RBCs) and hemoglobin (Hb) as a function of drug exposure and subject-specific characteristics. The dataset was based on data from 7 Phase 1 to Phase 3 studies (Table 1; N = 894 for VADA; N = 560 for ESA modeling) in healthy volunteers and subjects with NDD- or DD-CKD who were either ESA-naïve or ESA experienced but not receiving treatment at screening. Prior population PK modeling of VADA provided estimated drug exposures for VADA-treated subjects, while dose normalized to standard units (IU/kg/wk) was used as the exposure metric for subjects on ESA. Each of these exposure metrics could vary with time, as the dose was adjusted according to observed Hb response. This work evaluated alternative model structures, as well as covariate effects affecting Hb individual response. A similar model structure was found to describe early changes in RETICs and longer-term changes in Hb for both VADA and ESAs. In each case, the magnitude of response increases with increased drug exposure up to a maximum value (Emax), and the Emax values were similar between VADA and ESAs. Subject intrinsic predictors of response included eGFR, subject age, BMI, and serum albumin, while extrinsic factors affecting response included geographic region, limits on acceptable Hb values (which also differ by geographic region) and the presence of previous ESA treatment. Interestingly, Hb responses were also correlated with changes in serum hepcidin, a key regulator of iron homeostasis, following both VADA and ESA treatment. Differences between the response to VADA and ESA were also described, including differences in temporal changes in RETICs and Hb. Conclusion This model showed an exposure-response relationship between VADA or ESA treatment and changes in RETICs and Hb for ESA naïve or ESA-experienced CKD subjects. The model will be used to inform dosage recommendations for VADA based on patient characteristics.

The Efficacy of Mung Bean Drink with Inulin and Iron Tablets in the Erythropoiesis Response of Adolescent Girls with Iron Deficiency Anemia: A Randomized Controlled Trial

This study aims to determine the effectiveness of mung bean drink with inulin and iron tablets on the erythropoiesis response as characterized by changes in reticulocyte count of adolescent girls with iron deficiency anemia. This is a non-blinding, randomized controlled trial with pre-test-post-test with control groups research design which was conducted in Sleman Regency, Yogyakarta, Indonesia. Sixty-one adolescent girls with iron deficiency anemia were recruited from junior and senior high schools and then randomized into two groups. The treatment group (n=30) received iron tablets and a mung bean drink with inulin, whereas the control group (n=31) received iron tablets and a palm sugar drink. The intervention was carried out for 12 weeks. Data collection involved interviews, monitoring adherence to drinking, and blood tests. Data were analyzed using Chi-Square Tests, paired T-Tests, and Mann-Whitney Tests. The results showed that there was a significant increase in reticulocyte count after two weeks of intervention in the treatment group (p-value 0.0001) and the control group (p-value 0.001). After four and 12 weeks of intervention, reticulocyte counts of both groups decreased along with increasing hemoglobin levels. In conclusion, the mung bean drink with inulin and iron tablets is effective in the erythropoiesis response.

Comparison Between Manual and Automated Methods of Counting Reticulocytes and the Effect of Sample Storage on Reticulocyte Count: A Cross-Sectional Study from Southern India.

Reticulocyte count is a basic test in hematology. This study was done to compare manual and automated methods and to study the effect of sample storage on reticulocyte count. Analyses of samples (n = 86) were done at 2, 6, 24 and 48h after blood collection. Manual counting was done from both freshly prepared slide and stored slide by microscopy on new methylene blue stained smears. Automated enumeration was on Sysmex XT-2000i analyser (Ret search II). The values of immature reticulocyte fraction (IRF) and low fluorescence reticulocytes (LFR) were also recorded. Comparison between two methods was done by Spearman's correlation and Mann-Whitney test. Effect of storage was analysed by repeated measures ANOVA. There was strong positive correlation between both manual and automated methods at 2, 6, 24 and 48h. The differences between the manual and automated methods were not significant at 2, 6 and 24h (p 0.975, 0.967 and 0.227). The difference between the freshly prepared slide and stored slide were significant at 6, 24 and 48h (p 0.015, 0.004 and 0.001). The change in reticulocyte count with time, decrease in IRF and increase in LFR were not significant up to 6h but were significant at 24 and 48h after blood collection. Both the methods were accurate and correlated well with each other. Freshly prepared smears for manual counting were better than counting on stored slide. Up to 6h after blood collection results obtained by both methods are acceptable.

Absence of neocytolysis in humans returning from a 3-week high-altitude sojourn.

Total haemoglobin mass (tot-Hb) increases during high-altitude acclimatization. Normalization of tot-Hb upon descent is thought to occur via neocytolysis, the selective destruction of newly formed erythrocytes. Because convincing experimental proof of neocytolysis is lacking, we performed a prospective study on erythrocyte survival after a stay at the Jungfraujoch Research Station (JFJRS; 3450m). Newly formed erythrocytes of 12 male subjects (mean age 23.3years) were age cohort labelled in normoxia (110m) and during a 19-day high-altitude sojourn by ingestion of 13 C2- and 15 N-labelled glycine respectively. Elimination dynamics for erythrocytes produced in normoxia and at high altitude were measured by isotope ratio mass spectrometry of haem, by determining tot-Hb, reticulocyte counts, erythrocyte membrane protein 4.1a/4.1b ratio and by mathematical modelling. Tot-Hb increased by 4.7%±2.7% at high altitude and returned to pre-altitude values within 11days after descent. Elimination of 13 C- (normoxia) and 15 N- (high altitude) labelled erythrocytes was not different. Erythropoietin levels and counts of CD71-positive reticulocytes decreased rapidly after descent. The band 4.1a/4.1b ratio decreased at altitude and remained low for 3-4days after descent and normalized slowly. There was no indication of haemolysis. We confirm a rapid normalization of tot-Hb upon descent. Based on the lack of accelerated removal of age cohorts of erythrocytes labelled at high altitude, on patterns of changes in reticulocyte counts and of the band 4.1a/4.1b ratio and on modelling, this decrease did not occur via neocytolysis, but by a reduced rate of erythropoiesis along with normal clearance of senescent erythrocytes.

Reticulocyte count changes in paediatric patients with uncomplicated malaria treated with artemisinin combination therapy

Background: Acute malaria is associated with reticulocyte count depression, and artemisinin derivatives have also been shown to cause reversible count changesin patients with severe malaria. However, there has been no report on the effect of artemisinin on reticulocytecountwhen used in combination with other antimalarials, or the effect of artemisinin-based treatment on reticulocyte count changes in patients with uncomplicated malaria. Objective: This study reports the effects of artemisinin-based antimalarial treatments on reticulocytes among paediatric patients with uncomplicated malaria. Methods: The reticulocyte counts, haemoglobin, and platelet counts of children with uncomplicated malaria treated with artesunate-amodiaquine (116), artemether-lumefantrine (90), or amodiaquine (17) were measured before treatment (day 0) and then on days 3, 7, 14, and 28. Results: The fractional changes in reticulocyte counts were higher in the artesunate-amodiaquine and artemether-lumefantrine groups during the initial stages of treatment. However, the overall fractional reticulocyte change between acute illness and pre-illness levels was higher in the amodiaquine treated group. There was a negative correlation between haemoglobin and reticulocyte counts before treatment (day 0 ) and on all the follow up days. Conclusion: Treatment of uncomplicated malaria in children with artesunate-amodiaquine or artemether-lumefantrine was associated with less profound reticulocyte count changes compared with children treated with amodiaquine alone. These changes were most likely due to the rapid parasite clearance by the two artemisinin-based combination treatment regimens.

Reticulocyte count changes in paediatric patients with uncomplicated malaria treated with artemisinin combination therapy

Background: Acute malaria is associated with reticulocyte count depression, and artemisinin derivatives have also been shown to cause reversible count changes in patients with severe malaria. However, there has been no report on the effect of artemisinin on reticulocyte count when used in combination with other antimalarials, or the effect of artemisinin-based treatment on reticulocyte count changes in patients with uncomplicated malaria. Objective:This study reports the effects of artemisinin-based antimalarial treatments on reticulocytes among paediatric patients with uncomplicated malaria. Methods: The reticulocyte counts, haemoglobin, and platelet counts of children with uncomplicated malaria treated with artesunate-amodiaquine (116), artemether-lumefantrine (90), or amodiaquine (17) were measured before treatment (day 0) and then on days 3, 7, 14, and 28. Results: The fractional changes in reticulocyte counts were higher in the artesunate-amodiaquine and artemether-lumefantrine groups during the initial stages of treatment. However, the overall fractional reticulocyte change between acute illness and pre-illness levels was higher in the amodiaquine treated group. There was a negative correlation between haemoglobin and reticulocyte counts before treatment (day0) and on all the follow up days. Conclusion: Treatment of uncomplicated malaria in children with artesunate-amodiaquine or artemether-lumefantrine was associated with less profound reticulocyte count changes compared with children treated with amodiaquine alone. These changes were most likely due to the rapid parasite clearance by the two artemisinin-based combination treatment regimens

Efficacy of quadruple treatment on different types of pre-operative anaemia: secondary analysis of a randomised controlled trial.

In patients with pre-operative anaemia undergoing cardiac surgery, combination treatment with intravenous iron, subcutaneous erythropoietin alpha, vitamin B12 and oral folic acid reduces allogeneic blood product transfusions. It is unclear if certain types of anaemia particularly benefit from this treatment. We performed a post-hoc analysis of anaemic patients from a randomised trial on the 'Effect of ultra-short-term treatment of patients with iron deficiency or anaemia undergoing cardiac surgery'. We used linear regression analyses to examine the efficacy of a combination anaemia treatment compared with placebo on the following deficiencies, each representing a part of the combination treatment: ferritin and transferrin saturation; endogenous erythropoietin; holotranscobalamine; and folic acid in erythrocytes. Efficacy was defined as change in reticulocyte count from baseline to the first, third and fifth postoperative days and represented erythropoietic activity in the immediate peri-operative recovery phase. In all 253 anaemic patients, iron deficiency was the most common cause of anaemia. Treatment significantly increased reticulocyte count in all regression analyses on postoperative days 1, 3 and 5 (all p<0.001). Baseline ferritin and endogenous erythropoietin were negatively associated with change in reticulocyte count on postoperative day 5, with an unstandardised regression coefficient B of -0.08 (95%CI -0.14 to -0.02) and -0.14 (95%CI -0.23 to -0.06), respectively. Quadruple anaemia treatment was effective regardless of the cause of anaemia and its effect manifested early in the peri-operative recovery phase. The more pronounced a deficiency was, the stronger the subsequent boost to erythropoiesis may have been.

Off-Label Prescription of Hydroxycarbamide (Hydroxyurea, HU) for Severe Anemia: Preliminary Results from European Non-Interventional, Multicentric, Prospective Escort-HU Study

HU is licensed in Europe in the prevention of recurrent painful vaso-occlusive crises (VOC) including acute chest syndromes in adults, adolescents and children older than 2 years with sickle-cell disease (SCD).However, based on US and European expert panel recommendations (Yawn 2014, Habibi 2015) and results from placebo-controlled clinical trials, HU could be useful in SCD patients with severe anemia without VOC since it has been demonstrated to increase total Hb level (Wang 2011) and to decrease the need for blood transfusion.We hereby present preliminary results on effectiveness and safety data related to the prescription of HU for anemia from ESCORT-HU (European Sickle Cell Disease COhoRT - HydroxyUrea), a multicentric, prospective, non-interventional European study designed to collect long-term safety data on HU in SCD population.Between January 2009 and June 2017, 1841 patients were enrolled from 63 centers in France, Germany, Greece and Italy, amongst which 126 patients (6.8%) were started on HU for anemia from 34 centers. Of these 126, 96 were HU-naive. These HU-naive patients treated for anemia (‘anemic’ subpopulation) were selected for analysis to evaluate effectiveness and safety of HU in this indication and compared with data in HU-naive patients treated for other SCD indications.Demographic data and Hb genotypes are displayed in Table 1. The mean age, distribution of gender, Hb genotype and the mean HU dose at initiation were comparable in the ‘anemic’ subpopulation and the ‘non-anemic’ HU-naive cohort. Not surprisingly, mean Hb level at initiation was markedly lower in the ‘anemic’ subpopulation (7.07 ± 0.88 g/dl) than in the ‘non-anemic’ HU-naive cohort (8.71 ± 1.51 g/dl), with a lower proportion of patients with history of VOC and SCD-related hospitalization prior to HU initiation. The mean HU dose after 6 months was comparable in both groups (15.6 ± 3.83 mg/kg/day and 15.4 ± 4.11 mg/kg/day, respectively).Variation of blood parameters are displayed in Table 2. Similarly to what has been observed previously, a dramatic rise in Hb concentration (> 2 g/dl) was observed. This increase was comparable in absolute value to the increase observed in non-anemic patients. An increase in HbF was observed in the “anemic” subpopulation, with a near 2-fold increase in %HbF, markedly in children. Changes in reticulocyte counts were inconclusive due to small number of patients in the dataset.Safety of HU in the population of patients treated for anemia was evaluated by comparing incidence rates of non-SCD related adverse events (AEs) in HU-naive patients treated for anemia with the ‘non-anemic’ HU-naive ESCORT-HU subpopulation (Table 3). With mean follow-up periods of 18.3 months in ‘anemic’ subpopulation and 34.2 months in ‘non-anemic’ HU-naive cohort, preliminary results showed no striking difference in the incidence rate of reported AEs (total and serious) between the two populations (112.5% vs 139.8%, respectively for incidence rate of total AEs), and in the distribution of AEs by System Organ Class (SOC), at least in SOC where the number of adverse events was large enough to allow for comparison between the groups. Similarly, when focusing on AE causally related to HU (as judged by the investigators), the most frequently reported toxicity in the ‘anemic’ population was myelosuppression (anemia, neutropenia thrombocytopenia, pancytopenia reported in 4 children, one event each), as in the ‘non-anemic’ HU-naive cohort, with comparable incidence rates.In conclusion, even though HU is not licensed in Europe in severe chronic anemia, European and US expert panel guidelines recommend treatment with HU in this indication. Data from ESCORT-HU observational study on a subset of SCD patients treated off label in this indication confirmed total Hb level increase while the safety profile of HU in this subpopulation did not differ significantly from the ‘non-anemic’ HU-naive population. [Display omitted] DisclosuresDe Montalembert:Novartis: Consultancy, Honoraria, Research Funding; Addmedica: Consultancy, Honoraria, Research Funding. Brousse:Add Medica: Membership on an entity's Board of Directors or advisory committees. Galacteros:Addmedica: Membership on an entity's Board of Directors or advisory committees.

Effect of a Red Blood Cell Transfusion on Biological Markers Used to Determine the Cause of Anemia: A Prospective Study

BackgroundBlood test results required for the evaluation of anemia are considered difficult to interpret after red blood cell transfusion. However, this hypothesis is neither supported by a strong physiological rationale nor is it evidence based. MethodsWe conducted a prospective multicenter study to compare the values of key assays prior to and after a course of red blood cell transfusion in the emergency or internal medicine units in 4 university hospitals. The following parameters were measured prior to and within 48 to 72 hours after transfusion: complete blood count with reticulocyte count, direct Coombs' test, ferritin, transferrin saturation, soluble transferrin receptor, serum and erythrocyte folate, cobalamin, lactate dehydrogenase, bilirubin, haptoglobin, and C-reactive protein. We investigated the impact of transfusion on these parameters and assessed whether abnormal values prior to the transfusion became normal after transfusion (or conversely). ResultsThere were 77 patients included in the study. Changes in mean values of mean corpuscular volume, soluble transferrin receptor, erythrocyte folate, cobalamin, haptoglobin, lactate dehydrogenase, C-reactive protein, and direct Coombs' test were not statistically significant. Changes in reticulocyte count, ferritin, transferrin saturation, serum folate, and total bilirubin concentrations were statistically significant, but they remained in the same diagnostic category (normal or abnormal) in 79% to 98% of the cases; 97% of patients with iron deficiency still had low ferritin or transferrin saturation after a transfusion. ConclusionBlood tests performed after a one-time red blood cell transfusion can be used to establish the cause of anemia when they have not been performed before.

The effect of intravenous iron on postoperative transfusion requirements in hip fracture patients: study protocol for a randomized controlled trial.

BackgroundAnaemia following hip fracture is common. Approximately 30 to 45% of patients have haemoglobin concentrations below population norms on admission, and around 10% are severely anaemic. Anaemia on admission, and in the postoperative period, is associated with poor outcomes with regard to mobility, postoperative mortality and readmission. There is currently no clear consensus on the optimal method of managing perioperative anaemia in this group of frail patients with frequent comorbidity. Liberal red cell transfusion in the postoperative period does not appear to improve outcome, whereas tranexamic acid appears to reduce transfusion rate at the expense of increased cardiovascular morbidity. There are encouraging results from one centre with the use of agents to stimulate red cell production, including intravenous iron and erythropoietin. UK practice differs significantly from these patients and these studies, and it is not clear whether these promising results will translate to the UK population.Methods/DesignThis is a single-centre randomized controlled parallel group trial, in a British university hospital.Randomization is achieved using a website and computer-generated concealed tables. Participants are 80 patients 70 years or over with acute hip fracture undergoing operative repair. The intervention group receive three daily infusions of 200 mg iron sucrose, starting within 24 hours of admission. The control group receive standard hospital care at the discretion of the clinical team. Red cell transfusions for each group are given in accordance with standard clinical triggers. The primary outcome is an increase in mean reticulocyte count in the intervention group at day 7. Secondary outcome measures include haemoglobin concentrations, early and late transfusion rates, infectious and cardiovascular complications, mobility and 30-day mortality.DiscussionThis is a pilot study to demonstrate haematopoietic efficacy of intravenous iron in this setting. Hence, we have chosen to measure change in reticulocyte count rather than the more clinically relevant differences in haemoglobin concentration or transfusion rate. If our results are positive, the study will provide the necessary information for development of a full-scale trial of intravenous iron.Trial registrationCurrent Controlled Trials ISRCTN76424792; UK Medicines and Healthcare products Regulatory Authority (EuDRACT: 2011-003233-34).

Potential Risks of Hemolysis after Short-Term Administration of Analgesics in Children with Glucose-6-Phosphate Dehydrogenase Deficiency

To evaluate the risk of hemolysis in children with glucose-6-phosphate dehydrogenase (G6PD) deficiency after short-term administration of analgesics, such as paracetamol, ibuprofen, tramadol, sufentanil, and parecoxib. This was a prospective study of children with G6PD deficiency who were treated with analgesics for 3 days after undergoing surgery. Hemoglobin (Hb) concentration, reticulocyte count, unconjugated bilirubin level, lactate dehydrogenase level, and the presence of Heinz bodies on blood smear microscopy were assessed at baseline and after analgesic treatment. Telephone interviews and clinical reviews were provided during a 7-day study period. The primary outcome was evidence of hemolysis. Statistical analyses were done using the paired Student t test or Wilcoxon signed-rank test as appropriate. Ten male infants (mean age, 4.3 ± 1.3 years) completed the study. The mean decrease in (Hb) concentration was -0.2 g/dL (P, not significant). The mean reticulocyte count increased by 0.1% (95% CI, 0.08%-0.2%; P = .001). However, the change in reticulocyte count was not correlated with the changes in Hb concentration or other laboratory results and was not accompanied by the clinical signs and symptoms of hemolysis. Short-term administration of paracetamol, ibuprofen, tramadol, sufentanil, and parecoxib in therapeutic dosages did not increase the risk of hemolysis in children with G6PD deficiency.

Effects of Thyroid Hormone on A1C and Glycated Albumin Levels in Nondiabetic Subjects With Overt Hypothyroidism

OBJECTIVEWe aimed to determine the effects of thyroid hormone on A1C and glycated albumin (GA) in nondiabetic patients with overt hypothyroidism.RESEARCH DESIGN AND METHODSA1C levels were measured in 45 nondiabetic patients with overt hypothyroidism and 180 euthyroid control subjects. A1C, GA, fasting blood glucose (FBG), 1,5-anhydroglucitol, and erythrocyte indexes were determined in 30 nondiabetic patients with overt hypothyroidism before and after thyroid hormone replacement.RESULTSA1C levels were higher in patients with hypothyroidism compared with control subjects. A1C levels were decreased by thyroid hormone replacement. Thyroid hormone replacement increased serum erythropoietin, reticulocyte count, and mean corpuscular hemoglobin (MCH). The change in A1C level was significantly correlated with the change in reticulocyte count or MCH. Thyroid hormone replacement decreased serum levels of albumin and GA. However, FBG and 1,5-anhydroglucitol levels were not altered.CONCLUSIONSLevels of A1C and GA are spuriously high in nondiabetic patients with overt hypothyroidism.

Impact of C-reactive protein on absolute reticulocyte count in haemodialysis patients: the role of iron status

The exact mechanisms by which the effects of inflammation on erythropoiesis occur are still to be determined. We aimed to examine the relation between C-reactive protein (CRP) and erythropoiesis as quantified by the absolute reticulocyte count (RTC) and the possible effect of iron status on this relationship. As part of a study that follows the changes of haematologic parameters after the intravenous (IV) administration of iron in 93 stable haemodialysis (HD) patients, we made a cross-sectional analysis of baseline measurements and an analysis of changes in RTC 1 week after baseline measurements and iron administration. Multiple linear regression analysis revealed that RTC had a positive correlation with CRP; RTC had a negative correlation with reticulocyte haemoglobin content (CHr). An interaction was also found between CRP and CHr in that CRP had a significant relation to RTC only in those patients whose CHr was more than 31.2 pg. At lower values of CHr, the correlation between CRP and RTC was not significant. Five days after the IV administration of 200 mg iron sucrose, a significant increase of RTC was observed, only in those patients with elevated baseline CRP levels who also showed an increase in CHr levels from ≤ 31.2 pg at baseline to ≥ 31.2 pg post-administration, supporting the presence of an independent positive correlation between CRP and RTC when iron is adequate. It is indicated that, in HD patients, elevated CRP values are associated with increased erythroid production only when CHr is quite satisfactory.

Serum hepcidin level and erythropoietic activity after hematopoietic stem cell transplantation

The relationship between serum hepcidin, a key regulator of body iron homeostasis, and erythropoiesis was investigated before and after stem cell transplantation in 31 patients with hematopoietic malignancies. Serum hepcidin-25 was monitored using a liquid chromatography-tandem mass spectrometry-based assay system. Other iron- and erythropoiesis-related parameters and known hepcidin regulators, such as interleukin-6 and growth differentiation factor-15, were also monitored. The serum hepcidin level peaked one week after stem cell transplantation, followed by a gradual decrease with a parallel change in interleukin-6 and a reciprocal change in reticulocyte count. Multivariate regression analysis demonstrated that the serum hepcidin level at four weeks after stem cell transplantation showed significant inverse correlations with erythropoietic activity markers, such as the soluble transferrin receptor, but not with growth differentiation factor-15. These results indicate the existence of an unknown functional erythropoiesis-associated circulating factor, other than growth differentiation factor-15, that negatively regulates hepcidin production in stem cell transplantation settings.

Optimising Haemoglobin Response to Exogenous Erythropoietin in Anaemic Patients Treated in Routine Haemato-Oncology Practice.

Patients' response to treatment with human recombinant erythropoietin (Epo) for chemotherapy-associated anaemia varies between 50% and 70%. The cost-effectiveness of Epo may be maximized by targeting treatment at patients most likely to respond. In this study, modified ASH/ASCO guidelines were combined with a systematic approach to iron supplementation in order to maximize haemoglobin (Hb) response in iron deficient patients. Patients with haematological malignancy and chemotherapy-associated anaemia received Epo alone (n = 25) or Epo plus intravenous iron sucrose (iv iron) if functional iron deficiency was present (n=24). The cohort had a male/female ratio of 48:52% and a mean age 62.8 years (SD 12.8; range 24 to 81). Baseline measurements were repeated at 4-weekly intervals for a period of 32 weeks. Overall, 80% of cases experienced a Hb response greater than 1g/dl, with 65% of patients achieving a major Hb response (≥ 2g/dl increase above baseline). There was no difference in Hb response between the Epo alone vs. Epo plus iv iron groups (∅ 2.72 vs. 2.84 g/dl; p=0.831), indicating equivalent outcomes for functionally iron deficient patients treated with effective iv iron supplementation and iron replete patients. General Linear Modelling was used to explore the independent contributions of demographics, baseline iron parameters, and disease progression in predicting Hb response to Epo. In the final model three independent variables emerged as significant, which together accounted for 40% of variance in Hb response. Progression of the underlying malignancy was associated with a mean reduction in Hb response of 1.9g/dl (p<0.001). Lower baseline Hb was associated with an increased response - each 1g/dl decrement was associated with a mean increased response of 0.87g/dl (p=0.012). Early change in reticulocyte count (between baseline and early follow up (< 4 weeks) was found to be positively associated with Hb response - each additional 1% change was associated with a 0.016g/dl increase in Hb response (p=0.006). These findings are in contrast to previous reports that the response to Epo wasindependent of the outcome of the underlying malignancy anddiminished at lower Hb levels.Disease progression, baseline Hb and early increases in reticulocytes were all highly significantly correlated with the Hb response to Epo. In fact, in this cohort, all cases of non-response to Epo or loss of a response were associated with disease progression. To maximise response rates to Epo requires detection of functional iron deficiency and supplementation with iv iron. Furthermore, early reticulocyte response and disease progression should be closely followed and can help guide when to stop Epo therapy. This would allow rational use of resources and improve the health economics of Epo therapy by focusing on those most likely to benefit.

Erythropoietin with Iron Supplementation To Prevent Allogeneic Blood Transfusion in Total Hip Joint Arthroplasty

The optimum regimen of epoetin alfa for prevention of allogeneic blood transfusion is unknown. To determine whether a modified regimen of epoetin alfa reduces allogeneic blood transfusion in patients undergoing hip arthroplasty. Randomized, double-blind, multicenter trial comparing two modified dose regimens of epoetin alfa with placebo. 13 teaching hospitals and 4 community hospitals in Canada. 201 patients undergoing primary hip arthroplasty who had a hemoglobin concentration of 98 to 137 g/L and did not predonate blood. Patients were assigned in a 3:5:5 ratio to receive four weekly doses of epoetin alfa, 40 000 U (high-dose; n = 44) or 20 000 U (low-dose; n = 79), or placebo (n = 78), starting 4 weeks before surgery. All patients received oral iron supplementation, 450 mg/d, for 42 or more days before surgery. The primary end point was allogeneic transfusion. Secondary end points were thromboembolic events and change in reticulocyte count and hemoglobin concentration. Both modified epoetin alfa regimens significantly reduced the need for allogeneic transfusion: Five (11.4%) patients in the high-dose group (P = 0.001) and 18 (22. 8%) patients in the low-dose group (P = 0.003) had transfusion, compared with 35 (44.9%) patients in the placebo group. The hematologic response was substantial in patients who received epoetin alfa. In the high-dose group, low-dose group, and placebo group, the preoperative increase in reticulocyte count was 58.8, 37. 0 and 1.8 x 10(9) cells/L (P < 0.001), respectively, and the increase in hemoglobin concentration was 19.5, 17.2, and 1.2 g/L (P < 0.001). The incidence of thromboembolic events did not differ among groups. Both modified epoetin alfa regimens were effective compared with placebo in reducing allogeneic transfusion in patients undergoing hip arthroplasty. Patients who received high-dose epoetin alfa had the lowest transfusion rate.

Troglitazone has no effect on red cell mass or other erythropoietic parameters

Troglitazone is a new anti-diabetic agent for the treatment of type 2 diabetes. In placebo-controlled trials troglitazone improves glycaemic control, reduces hyperinsulinaemia and has beneficial effects on blood lipids. However, minor, reversible reductions in erythrocyte count, haemoglobin and haematocrit with no associated clinical symptoms have been observed in some troglitazone-treated patients. The primary objective of the present study was to determine if these changes could be explained by a decrease in red cell mass or change in plasma volume. Twenty-four healthy males were randomized in a double-blind manner to troglitazone (200 or 600 mg per day) or placebo for 6 weeks. Blood samples for the measurement of red cell mass and plasma volume were obtained in the 2 weeks prior to treatment and after 6 weeks of treatment. Reticulocyte and erythrocyte counts, haemoglobin and haematocrit were also measured. At the end of the treatment period there were no statistically significant changes in red cell mass. Similarly there were no changes in reticulocyte count, erythropoietin or soluble transferrin receptors. These data indicate that troglitazone does not affect erythropoiesis. In addition, troglitazone was not associated with increased red blood cell destruction or haemolysis. There was a trend towards increased plasma volume in the troglitazone groups: increases of 2.5 ml x kg(-1) (5.7% increase) in the troglitazone 200 mg group and 3.4 ml x kg(-1) (7.8% increase) in the troglitazone 600 mg group were observed compared with placebo. These data suggest that dilutional effects related to a modest increase in plasma volume may explain the haematological changes seen in other clinical trials with high doses of troglitazone, although this study has shown that the changes in plasma volume are not statistically significant.

Intravascular stents do not cause microangiopathic hemolysis or thrombotic microangiopathy

An increased incidence of TTP has been noted among patients receiving intravascular stents to improve patency in diseased coronary, renal, and peripheral arteries. Placement of transjugular intrahepatic porto-systemic shunt stents is often associated with subsequent development of severe hemolysis. We have propsectively studied the development of microangiopathic hemolysis or TTP in patients undergoing intravascular stent placement for peripheral vascular or renal artery disease. Hemolysis was evaluated both before and after stent placement by measuring complete blood count, total bilirubin, lactate dehydrogenase (LDH), haptoglobin and reticulocyte count, and examining peripheral blood films of all patients. Coagulation parameters, blood urea nitrogen and creatinine were measured to exclude disseminated intravascular coagulation or thrombotic thrombocytopenic purpura as a potential cause of hemolysis. Seventeen patients (median age 69 years) were evaluated. One patient was on ticlopidine. Mean hematocrit fell from 41.8% pre-stenting to 35.5% post-stenting (P = 0.003) but without significant change in reticulocyte count (1.7 vs. 1.6%, P = 0.605), LDH (546 vs. 560 IU/l; P = 0.836), bilirubin (0.62 vs. 0.63 mg/dl; P = 1.0), or haptoglobin (183 vs. 158 mg/dl; P = 0.083). Thus, this drop in hematocrit could not be attributed to hemolysis. Peripheral blood films revealed fewer than 1% schistocytes before and after stent placement in all cases. Absence of significant changes in mean platelet count (240 vs. 210 × 109/L; P = 0.088), fibrinogen (385 vs. 378 mg/dl; P = 0.789), BUN (24.5 vs. 16.8; P = 0.079), and creatinine (1.38 vs. 1.24; P = 0.757) argue against development of TTP or DIC resulting from stent placement. No patient developed new renal impairment, a neurological syndrome, or unexplained fever after stent placement. At a mean of 6 weeks follow-up after stent placement, patients have not developed signs of hemolytic anemia or worsening renal function. Our findings argue against a primary risk of microangiopathic hemolytic anemia or TTP due to intravascular stents in patients not receiving ticlopidine. J. Clin. Apheresis 14:130–134, 1999. © 1999 Wiley-Liss, Inc.

Reticulocyte hemoglobin: an integrated parameter for evaluation of erythropoietic activity.

Traditional reticulocyte counts provide only a partial estimate of the erythropoietic bone marrow activity and do not account for qualitative variations of reticulocyte cellular indexes and hemoglobin content in particular. We have studied a new integrated parameter, reticulocyte hemoglobin (retHb), that quantifies in grams per liter the hemoglobin contained in the circulating reticulocyte compartment and is obtained by multiplying the absolute reticulocyte count and the reticulocyte cell hemoglobin content. In 50 normal control subjects, retHb values were 1.76 +/- 0.59 g/L. The retHb values were lower in patients double heterozygous for HbS and HbC (SC disease) (3.33 +/- 1.52 g/L, n = 13) compared with homozygous HbS disease (SS) with concomitant alpha-thalassemia (5.27 +/- 1.51 g/L and 5.48 +/- 1.06 g/L for 12 patients with 3 alpha-genes and 3 patients with 2 alpha-genes, respectively) and to SS disease with no alpha-thalassemia (6.47 +/- 3.05, n = 20). The hemoglobin contained in the red blood cell pool (rbcHb) also can be calculated by subtracting retHb from the total hemoglobin. The ratio between the two pools (rbcHb/retHb, normal value 76.6 +/- 21.9, n = 50) provides a rough estimate of red blood cell survival. It was 9.8 +/- 4.1 in SS disease, 16.2 +/- 10.1 and 14.7 +/- 5.0 in SS disease with 3 and 2 normal alpha-genes, respectively, and 36.6 +/- 17.8 in SC disease with no alpha-thalassemia. We also studied retHb in patients receiving hydroxyurea therapy for SS disease, intravenous or oral iron for iron deficiency, or recombinant human erythropoietin (r-HuEPO) therapy. All these conditions are characterized by changes in reticulocyte counts and marked variations in reticulocyte cellular hemoglobin contents, which can be integrated into the retHb parameter. Measurement of retHb and the rbcHb/retHb ratio may provide an estimate of the reduction in red blood cell survival and the severity of hemolysis in various anemias and allow more precise monitoring of the response to hydroxyurea, iron, r-HuEPO, or other therapies.

A randomized, double-blind, placebo-controlled trial of recombinant erythropietin in treatment of the anemia of bronchopulmonary dysplasia

Because anemia in patients with bronchopulmonary dysplasia is characterized by inappropriately low serum concentrations of erythropoietin but increased in vitro sensitivity of erythroid progenitors to erythropoietin, we speculated that administration of human recombinant erythropoietin would correct this anemia. Fifteen infants with the anemia of bronchopulmonary dysplasia were randomly assigned to receive erythropoietin or placebo subcutaneously for 10 days. Changes in reticulocyte count, hematocrit, blood lactate concentration, neutrophil count, platelet count, heart rate, oxygen requirement, weight gain, and number of transfusions were assessed. In the 10 erythropoietin recipients (99 +/- 12 days of age), hematocrit values increased from 0.325 +/- 0.006 to 0.381 +/- 0.013 (mean +/- SEM; p < 0.005) and reticulocyte counts from 122 +/- 20 to 446 +/- 48 x 10(3)/microliters (p < 0.005); lactate values remained unchanged. In the five placebo recipients (91 +/- 12 days of age), hematocrits and reticulocyte counts remained unchanged, and lactate values increased from 0.73 +/- 0.14 to 1.34 +/- 0.25 mumol/gm (p < 0.05). During the 30 days after the treatment period, one erythropoietin recipient and four placebo recipients were given transfusions. Other measured variables remained unchanged in both groups. We conclude that erythropoietin is effective in treatment of the anemia of bronchopulmonary dysplasia.