losartan-potassium and alpha-Thalassemia

Haemoglobin E-beta thalassaemia (Hb E/β-thalassaemia) is the genotype responsible for approximately one-half of all severe beta-thalassaemia worldwide. The disorder is characterized by marked clinical variability, ranging from a mild and asymptomatic anaemia to a life-threatening disorder requiring transfusions from infancy. The phenotypic variability of Hb E/β-thalassaemia and the paucity of long-term clinical data, present challenges in providing definitive recommendations for the optimal management of patients. Genetic factors influencing the severity of this disorder include the type of beta-thalassaemia mutation, the co-inheritance of alpha-thalassaemia, and polymorphisms associated with increased production of foetal haemoglobin. Other factors, including a variable increase in serum erythropoietin in response to anaemia, previous or ongoing infection with malaria, previous splenectomy and other environmental influences, may be involved. The remarkable variation, and the instability, of the clinical phenotype of Hb E beta-thalassaemia suggests that careful tailoring of treatment is required for each patient, and that therapeutic approaches should be re-assessed over-time.

Topics: alpha-Thalassemia; beta-Thalassemia; Blood Transfusion; Erythropoietin; Fetal Hemoglobin; Genotype; Hemoglobin E; Humans; Malaria; Phenotype; Polymorphism, Genetic; Splenectomy

α-Thalassemia is one of the most important genetic modulators of sickle cell disease (SCD). Both beneficial and detrimental effects have been described previously. We use a 12-year data set on a large cohort of patients with HbSS (n = 411) and HbSC (n = 146) to examine a wide range of these clinical and laboratory associations. Our novel findings are that α-thalassemia strongly reduces erythrocyte potassium chloride co-transporter (KCC) activity in both HbSS and HbSC (p = .035 and p = .00045 respectively), suggesting a novel mechanism through which α-thalassemia induces a milder phenotype by reducing red cell cation loss. This may be particularly important in HbSC where reduction in mean cell hemoglobin concentration is not seen and where KCC activity has previously been found to correlate with disease severity. Additionally, we show that α-thalassemia not only increases hemoglobin in patients with HbSS (p = .0009) but also reduces erythropoietin values (p = .0005), demonstrating a measurable response to improved tissue oxygenation. We confirm the reno-protective effect of α-thalassemia in patients with HbSS, with reduced proteinuria (p = .003) and demonstrate a novel association with increased serum sodium (p = .0004) and reduced serum potassium values (p = 5.74 × 10

Topics: alpha-Thalassemia; Anemia, Sickle Cell; Cations; Erythrocytes; Erythropoietin; Hemoglobin SC Disease; Hemoglobin, Sickle; Humans

Fetal anemia is common in malaria-endemic areas and a risk factor for anemia as well as mortality during infancy. Placental malaria (PM) and red cell abnormalities have been proposed as possible etiologies, but the relationship between PM and fetal anemia has varied in earlier studies, and the role of red cell abnormalities has not been studied in malaria-endemic areas. In a Tanzanian birth cohort study designed to elucidate the pathogenesis of severe malaria in young infants, we performed a cross-sectional analysis of risk factors for fetal anemia. We determined PM status, newborn red cell abnormalities, and maternal and cord blood levels of iron regulatory proteins, erythropoietin (EPO), cytokines and cytokine receptors. We examined the relationship between these factors and fetal anemia. Fetal anemia was present in 46.2% of the neonates but was not related to PM. Maternal iron deficiency was common (81.6%), most frequent in multigravidae, and interacted with parity to modify risk of fetal anemia, but it was not directly related to risk. Among offspring of iron-deficient women, the odds of fetal anemia increased with fetal α

Topics: Adult; alpha-Thalassemia; Anemia; Biomarkers; Cross-Sectional Studies; Cytokines; Erythropoietin; Female; Fetal Diseases; Fetus; Hemoglobins; Humans; Infant, Newborn; Iron; Iron Deficiencies; Malaria; Male; Maternal Health; Parity; Placenta; Pregnancy; Pregnancy Complications, Parasitic; Risk Assessment; Risk Factors; Tanzania; Transferrin; Young Adult

Topics: Adult; alpha-Thalassemia; Erythropoietin; Female; Hemoglobins; Humans

Topics: alpha-Thalassemia; Anemia; Darbepoetin alfa; Erythropoietin; Fatigue; Female; Hematinics; Humans; Pregnancy; Pregnancy Complications, Hematologic; Prenatal Care; Recombinant Proteins

Although it is almost certain that alpha(+)-thalassemia protects against malaria, the mechanisms for that are still unknown. It has been suggested that an increased number of young circulating red blood cells in alpha(+)-thalassemic children, as a result of some degree of ineffective erythropoiesis, could be related to the high frequencies of the alpha(+)-thalassemic allele in malaria endemic areas. Reticulocyte evaluation in this condition, however, has been poorly performed so far. Our objective was to determine the reticulocyte number and maturation degree, in addition to the soluble transferrin receptor and serum erythropoietin levels, in alpha(+)-thalassemia heterozygotes, comparing them with normal alpha-genotype controls. One hundred twenty-one alpha(+)-thalassemia carriers (-alpha(3.7)/alphaalpha) and 249 controls (alphaalpha/alphaalpha), all of them with normal serum ferritin levels, were subclassified according to age (1-5, 6-10, 11-15, 16-20, and over 20 years old). Reticulocyte analyzes were carried out by flow cytometry and sTfR and s-Epo levels determined by immunonephelometry and chemiluminescence, respectively. The comparisons did not show any significant difference between thalassemics and controls regarding the reticulocyte parameters [percentages and absolute values, P = 0.2643 and 0.5421; high, medium, and low maturation degree, P = 0.2579, 0.2196, and 0.4192; RET maturity index (RMI), P = 0.2471, respectively], as well as the s-Epo levels (P = 0.5711). The sTfR concentrations were higher in the thalassemic group (P = 0.0001), but statistical significance was due only to the 1-5 and over 20 subgroups (P = 0.0082 and 0.0436, respectively). The results found here are compatible with a compensated erythropoiesis and do not confirm the hypothesis mentioned above.

Topics: Adolescent; Adult; alpha-Thalassemia; Brazil; Child; Child, Preschool; Erythropoiesis; Erythropoietin; Female; Ferritins; Flow Cytometry; Heterozygote; Humans; Infant; Malaria; Male; Nephelometry and Turbidimetry; Receptors, Transferrin; Reticulocyte Count; Reticulocytes

Thalassemia is a common genetic disorder among the South Chinese. To see if thalassemia would adversely affect the erythrocyte response to recombinant human erythropoietin (rHuEPO, Epogen) in dialysis patients, the response to rHuEPO in 4 dialysis patients with thalassemic traits (thal-t) was compared with that of 4 control patients who were matched for age, sex, mode of dialysis and baseline hemoglobin levels over a 6-month period. Patients with thal-t showed a reduced erythrocyte response to rHuEPO compared to control dialysis patients as reflected by a reduced reticulocyte index, a slower rise in hemoglobin or hematocrit levels, requirement of a higher cumulated dose of rHuEPO to achieve a target hemoglobin of 10 g/dl and a higher maintenance dose of rHuEPO. A dialysis patient with hemoglobin H disease (HbHD) was also studied. He failed to respond to rHuEPO despite that the dose was increased to 250 U/kg/week. In contrast, his matched control dialysis patient, despite a lower baseline hemoglobin level (6.1 versus 8.8 g/dl), was able to reach a target hemoglobin level of 10 g/dl by 6 weeks and could be maintained at this level with 50 U/kg/week. The patient with HbHD had splenomegaly and a higher baseline serum erythropoietin level, reticulocyte count, serum bilirubin, serum ferritin and serum iron saturation than control patients and patients with thal-t. It was concluded that thal-t reduces the erythrocyte response to rHuEPO in dialysis patients and that in the presence of active hemolysis and enhanced endogenous erythropoietin secretion, dialysis patients with HbHD are resistant to treatment with rHuEPO.

Topics: Adult; alpha-Thalassemia; Anemia; beta-Thalassemia; Erythropoietin; Female; Humans; Kidney Failure, Chronic; Male; Recombinant Proteins; Renal Dialysis

Topics: Adult; alpha-Thalassemia; Anemia; Erythropoietin; Female; Humans; Kidney Failure, Chronic; Peritoneal Dialysis, Continuous Ambulatory; Recombinant Proteins; Transferrin