Increase In Total Hb Research Articles

Evidence of an association between cardiac-locomotor synchronization and lower leg muscle blood perfusion during walking.

[Purpose] The purpose of this study was to investigate whether the occurrence of cardiac-locomotor synchronization (CLS) improves lower leg muscle blood perfusion during walking. [Subjects and Methods] Eleven healthy men were studied while performing two treadmill protocols. The CLS protocol involved subjects walking at the frequency of their heart rate (HR) to induce CLS. The free protocol (reference) involved subjects walking at a self-selected cadence. The treadmill load was identical in the two protocols. Electrocardiographic signals for HR, foot switch signals for step rate and near-infrared spectroscopy (NIRS) signals for total haemoglobin (total Hb) in the lower leg muscles were measured continuously for 10 min after HR reached a steady state. [Results] The mean HR and mean step rate did not differ between the CLS and free protocols. However, total Hb was significantly higher in the CLS protocol than in the free protocol. The rate of increase in total Hb positively correlated with the strength of CLS. [Conclusion] These results suggest that the occurrence of CLS enhances lower leg muscle blood perfusion by increasing the strength of CLS during walking.

A Phase 2 Trial Of The Fetal Hemoglobin Inducer HQK-1001 (2,2-dimethylbutyrate, Sodium Salt) In Non-Transfusion-Dependent β-Thalassemia

Treatment of β-thalassemia is still largely dependent on supportive care, including blood transfusions and iron chelation. No oral drugs have been shown to consistently improve the severe anemia in thalassemia. Hematopoietic stem cell transplantation is potentially curative, but only a fraction of patients are eligible. Reactivation of fetal globin gene expression and increased γ-globin chain production is an attractive therapeutic approach, because it can compensate for defective β-globin chain production and the consequent α/β-chain imbalance that is a hallmark of β-thalassaemia.HQK-1001 (2,2-dimethylbutyrate, sodium salt), a new butyrate derivative with moderate potency but greater bioavailability, no cytotoxicity, and no HDAC-inhibitory activity compared to earlier butyrates, was shown to stimulate γ-globin production and erythropoiesis in animal models and in vitro. HQK-1001 reactivates γ-globin gene expression by inducing targeted dissociation of the inhibitory complex HDAC3 and its adaptor protein NCoR from the γ-globin gene promoter. HQK-1001 also enhances erythropoiesis by prolonging phosphorylation and activation of STAT-5, and enhancing Bcl-xL expression. In a multicenter dose-escalation study, HQK-1001 administered orally at 10, 20, 30 and 40 mg/kg once daily for 8 weeks in 21 subjects with non-transfusion-dependent β-thalassemia (NTDT) was well-tolerated and increased fetal hemoglobin (Hb F) in most subjects, with best results observed at 20 mg/kg. This single-center study (NCT01642758) evaluated HQK-1001 administered at 20 mg/kg/day for a longer duration than previously studied.Patients 18-50 years old with NTDT of Mediterranean phenotypes were eligible if their hemoglobin (Hb) was between 6.0 and 9.0 g/dL within the prior 30 days and had no transfusions within the prior 3 months. HQK-1001 was administered at 20 mg/kg once daily for 24 weeks. Folic acid was administered daily and oral iron supplementation was prescribed if serum ferritin was <700 ng/mL and stopped if ferritin exceeded 1000 ng/mL. Clinical and laboratory assessments were performed every 4 weeks. Ten subjects were enrolled, 7 male and 3 female, with a mean age of 29.4 years (range: 18-52 years). Eight subjects were splenectomized and 2 had palpable splenomegaly. Mean laboratory values at baseline were Hb F = 26.6% (range: 7.9-73.8%), Hb = 7.7 g/dL (range: 6.2-9.6 g/L) and reticulocytes = 10.9% (range: 7.1-15.7%). β-thalassemia mutations included homozygous IVS I-6 (C-T) in 7 of 10 subjects; and single subjects with homozygous cd29, homozygous IVS I-110 (G-A), and heterozygous IVSI-110 (G-A) / IVS II-I (G-A). One subject discontinued participation at Week 16 because of worsening anemia requiring a transfusion. Hb F increased in all subjects (range: 2.3-9.8%), with a mean increase of 4.8% (p < 0.0001). Total Hb increased in 7 subjects, with a mean increase of 0.6 g/dL (range: 0.1-1.5 g/dL) in those with increased Hb F. Adverse events were mild or moderate and reversible; fatigue, in 3 subjects, was the most common, followed by nausea, epigastric pain, dyspepsia, and fever, reported in 2 subjects each. There were mild and reversible increases in AST in 5 subjects and ALT in 4. Analyses of 3 major genetic modifier loci influencing baseline HbF levels identified favorable SNPs in the HMIP locus in 4 subjects, in BCL-11A in 3 subjects, and Xmn-I in one. No association was identified between specific modifiers and pharmacodynamic responses in this small group.In conclusion, HQK-1001 was well-tolerated and resulted in increased Hb F in all subjects and a modest increase in total Hb in 70% of subjects. The findings suggest that further HQK-1001 studies enrolling larger numbers of genetically characterized patients for longer periods appear warranted.Funding for this study was provided by a research grant from HemaQuest Pharmaceuticals and by the Georges N. Khoriaty Foundation. Disclosures:Inati:HemaQuest Pharmaceuticals: Research Funding. Perrine:Phoenicia BioSciences, Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding; HemaQuest Pharmaceuticals: Equity Ownership. Ghalie:HemaQuest Pharmaceuticals: Employment.

Effect of change in blood volume in skin plus active muscle on heart rate drift during submaximal exercise

The purpose of the present study was to examine the effect of change in blood volume in skin plus active muscle on heart rate drift during moderate exercise and heavy exercise for 30 min. Total hemoglobin concentration (Total Hb) in the vastus lateralis muscle plus its skin was determined by near-infrared spectroscopy. Total Hb significantly increased and remained stable from 20 min in moderate exercise and from 10 min in heavy exercise. Heart rate (HR) rapidly increased until 3 min and showed a steady state in moderate exercise. HR at 30 min was significantly higher than that at 3 min in moderate exercise. HR rapidly increased until 3 min and then gradually but significantly increased in heavy exercise. Increase in total Hb was not significantly related with HR after 3 min of exercise when HR was around 120 beats per min in moderate exercise. Increase in total Hb was significantly related with HR from 3 min to 10 min in the heavy exercise (correlation coefficients ranged from 0.959 to 0.702). It is concluded that an increase in the blood volume in skin plus active muscle is not simply associated with HR drift.

Hydroxyurea for the Prevention of Stroke and Other Vasoocclusive Complications in Children with Sickle Cell Disease.

Due to the immigration of families of Mediterranean, Asian and African origins to Switzerland an increasing number of children with Sickle Cell Disease (SCD) are being followed in our centers. The Swiss Pediatric Sickle Cell Disease Registry is aimed to study prognostic aspects and the outcome of different therapeutic approaches. Particularly, indications for hydroxyurea treatment and the effects of its long-term use are assessed.The risk of stroke in children with sickle cell disease (SCD) is approximately 200–300-fold greater compared to healthy children. 10% of children with SCD have a specially high risk for stroke with an incidence of 1 in 100 children per year. The US stroke prevention (STOP) trial has demonstrated the benefit of regular red cell transfusions for stroke prevention; however hemochromatosis is frequent and blood-borne infections can occur. Hydroxyurea (HU) can be a therapeutic alternative for the prevention of stroke in children with SCD and other severe vasoocclusive complications (VOC).From 52 children in our centers with SCD or with compound hemoglobinopathies 27 (median age 10.5, range 3.8–19 y) are treated with HU and were followed for 9–101 (mean 47) months. 16 received HU for recurrent VOC, including 4 children with chest syndrome. Two children recieved HU for silent cerebral infarctions and after stroke, respectively (Jehovas Witness). In 9 children HU was commenced for pathological transcranial dopppler ultrasonography (TCD) results according to the STOP trial criteria. TCDs were performed in all SCD patients once a year, in children with conditional TCDs every 6 months, and every 3 months in patients with pathological TCD results. Upon observation of two pathological TCDs at 2–3 months interval, HU was initiated with 10 to maximally 30 mg/kg/day.HU was well tolerated in all patients and no leuko- or neutropenia was observed. No stroke, stroke recurrence, chest syndrome or splenic sequestration was observed during HU treatment and the average number of hospital days/y before (9d) and after 12 months of HU (3d) were reduced significantly (P=0.002). However after 12–24 months, abnormal lung function and growth retardation did not improve significantly. Laboratory studies documented a significant increase in total Hb (mean 79 to 93 g/l; P=0.03), HbF (9 to 23%; P=0.0001) and MCV (83 to 94 fl; P=0.001) and a significant decrease of HbS (86 to 71%; P<0.0001), WBC (7,8 to 5.4; P<0.05) and bilirubin (54 to 36 umol/l; P<0.05) after 12 months of HU. In children that had received HU for pathological TCDs the increase of HbF resulted in a reduction of the middle cerebral arteries blood flow velocities as soon as after 5–7 months.We conclude that HU is a promising therapeutic alternative for the prevention of stroke and other VOC in SCD. Safety and efficacy of this treatment in children has to be assessed by further long-term studies.

Biotin-Labeled RBC Survival in Thalassemia and Impact of Treatment.

Determination of red blood cell (RBC) survival in the peripheral blood, to evaluate the efficacy of pharmacological agents that augment fetal hemoglobin (HbF) and total hemoglobin (Hb) in patients with beta-thalassemia, has not been implemented. We report the use of biotin labeling, a nonisotopic, safe and effective method to determine the erythrocyte lifespan, proven to be equivalent to 51Cr.We studied RBC survival in 9 Hemoglobin E-β-thalassemia (ET) patients, 4 thalassemia intermedia (TI) patients and compared RBC survival to normal control. Repeat measures were performed in 3 ET patients while on hydroxyurea (HU) treatment at 15–19 mg/Kg/day. RBC from 30 ml blood were ex-vivo biotinylated under sterile conditions using EZ-Link Sulfo-NHS-Biotin (Pierce), and re-infused to the patient as described before (Franco et al,1998). At set time points, the number of biotinylated cells was determined in small blood samples by flowcytometry using fluorescently labeled strepavidin. All patients tolerated the procedure well without an indication of re-infusion induced infection or anti-biotin antibody related hemolysis. The presence of biotinylated cells in the circulation was followed until only 0.05-0.08% biotinylated cells could be detected. The data were mathematically fitted to 100–100*[1-(1/T)*t]exp(-kt), where t is the time point, T is the extinction time, and k the exponential rate of RBC removal. The control data showed a linear removal rate (k=0), and a T of 100 days (R=0.95), consistent with a normal red cell life span. In the 9 ET and 4 TI patients, a faster disappearance of biotinylated cells was noted, and the number of surviving (biotinylated) cells in the population followed an exponential pattern, consistent with random removal (k=0.033, R= 0.97). Mean survival was 43±11 and 36±15 days, respectively. The 3 patients who received 10–12 months of HU treatment had a mean 0.8 gr/dL increase in their Hb and 20% increase in HbF. However, no difference was found in the RBC survival curves of these patients (k=0.034, R= 0.97), as compared to the non treated patients. One patient who was treated with HU and Erythropoietin (500u/Kg x3/wk) and had a 1.6 gr/dL increase in hemoglobin and RBC survival analysis showed the biotinylated cells to follow a similar survival curve. While these results cannot exclude a longer survival in selected cells, specifically those containing higher HbF, the overall effect of HU treatment has not proven to prolong the lifespan of labeled thalassemia erythrocytes.These results indicate that biotin label provides RBC survival characteristics in thalassemia patients. The method has advantages over 51Cr, including lack of radioactivity, avoiding labeling elution, low expense and recovery of labeled cells after prolonged time in the circulation. Moreover, the method is a valuable tool to measure effect of various treatments on the survival characteristics of the thalassemia erythrocytes. Preliminary findings indicate that despite the effect of HU on an increase in HbF and a mild to moderate increase in total Hb, the overall thalassemic erythrocyte lifespan has not increased, suggesting other mechanisms for these results including erythroid expansion, improved effective erythropoiesis and cell selection.

Splenectomy in patients with sickle-cell disease

Splenic complications of sickle-cell disease (SCD) are associated with morbidity, and in some it may lead to mortality. This paper presents our experience with 43 patients with SCD who had splenectomy as part of their management. The records of 43 patients with SCD who had splenectomy were examined for age at operation, sex, hemoglobin (Hb) electrophoresis, indication for splenectomy, pre- and postoperative medications, operative procedures, and postoperative complications. The indications for splenectomy were acute splenic sequestration crisis (ASSC) in 21 patients, hypersplenism in 15, and splenic abscess in 7. In 17 patients, the spleen was also found to be massively enlarged causing discomfort and intervening with everyday activity. For those with hypersplenism, there was a significant postoperative increase in total Hb (P < 0.0001), hematocrit (P < 0.0001), white blood cells (P < 0.0001), and platelet count (P < 0.0001). With careful perioperative management and proper follow-up, splenectomy in patients with SCD is beneficial in reducing their transfusion requirements and its attendant risks, eliminating the discomfort from mechanical pressure of the enlarged spleen, avoiding the risks of ASSC, and managing splenic abscess.

MB-02 Cells undergo fetal to adult globin gene switching in response to erythropoietin

The recently described MB-02 human cell line requires Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) for continuous growth and terminally differentiates into enucleate, hemoglobinized cells in response to erythropoietin. Here, analysis of globin production now demonstrates that uninduced MB-02 cells produce α globin and the fetal globin chains Gγ and Aγ in a ratio of 1:3. Addition of erythropoietin results in de novo synthesis of β globin chains and a marked increase in total Hb/ cell. Thus, the MB-02 cell line partially recapitulates the fetal to adult globin switch that occurs during erythroid and human fetal development and provides a new clonal human erythroid progenitor system for investigating the biochemical and molecular events involved in globin gene switching.