Impact of ZBTB7A hypomethylation and expression patterns on treatment response to hydroxyurea.

BACKGROUND: We aimed to clarify the emerging epigenetic landscape in a group of genes classified as "modifier genes" of the ß-type globin genes (HBB cluster), known to operate in trans to accomplish the two natural developmental switches in globin expression, from embryonic to fetal during the first trimester of conception and from fetal to adult around the time of birth. The epigenetic alterations were determined in adult sickle cell anemia (SCA) homozygotes and SCA/ß-thalassemia compound heterozygotes of Greek origin, who are under hydroxyurea (HU) treatment. Patients were distinguished in HU responders and HU non-responders (those not benefited from the HU) and both, and in vivo and in vitro approaches were implemented. RESULTS: We examined the CpG islands' DNA methylation profile of BCL11A, KLF1, MYB, MAP3K5, SIN3A, ZBTB7A, and GATA2, along with γ-globin and LRF/ZBTB7A expression levels. In vitro treatment of hematopoietic stem cells (HSCs) with HU induced a significant DNA hypomethylation pattern in ZBTB7A (p*, 0.04) and GATA2 (p*, 0.03) CpGs exclusively in the HU non-responders. Also, this group of patients exhibited significantly elevated baseline methylation patterns in ZBTB7A, before the HU treatment, compared to HU responders (p*, 0.019) and to control group of healthy individuals (p*, 0.021), which resembles a potential epigenetic barrier for the γ-globin expression. γ-Globin expression in vitro matched with detected HbF levels during patients' monitoring tests (in vivo) under HU treatment, implying a good reproducibility of the in vitro HU epigenetic effect. LRF/ZBTB7A expression was elevated only in the HU non-responders under the influence of HU. CONCLUSIONS: This is one of the very first pharmacoepigenomic studies indicating that the hypomethylation of ZBTB7A during HU treatment enhances the LRF expression, which by its turn suppresses the HbF resumption in the HU non-responders. Its role as an epigenetic regulator of hemoglobin switching is also supported by the wide distribution of ZBTB7A-binding sites within the 5' CpG sequences of all studied human HBB cluster "modifier genes." Also, the baseline methylation level of selective CpGs in ZBTB7A and GATA2 could be an indicator of the negative HU response among the ß-type hemoglobinopathy patients.

National registry of hemoglobinopathies in Greece: updated demographics, current trends in affected births, and causes of mortality.

National registries constitute an invaluable source of information and contribute to the improvement of hemoglobinopathy management. Herein, we present the second updated report of the National Registry for Haemoglobinopathies in Greece (NRHG) and critically discuss the time trends in demographics, affected births, and causes of mortality. Thirty-eight Greek hemoglobinopathy units reported data from diagnosis to the last follow-up or death by retrospectively completing an electronic form. Four thousand thirty-two patients were eligible for inclusion; more than half of them had thalassaemia major. Compared to the previous report, a reduction in the total number of all hemoglobinopathies except for hemoglobinopathy "Η" was evident. The total number of affected births was also reduced; most of them were attributable to diagnostic errors and lack of awareness. Importantly, data on iron overload are reported for the first time; although most patients had low or moderate liver iron concentration (LIC) values, a non-negligible proportion of patients had high LIC. The burden due to heart iron overload was less prominent. Cardiac- and liver-related complications are the major causes of morbidity and mortality. From 2000 to 2015, a decrease in heart-related deaths along with an increase in liver-associated fatalities was observed. The Hellenic Prevention Program along with advances in chelation regimens and iron status monitoring have resulted in improved patient outcomes. The NRHG gives insight into the effectiveness of prevention programs, the therapeutic management of hemoglobinopathies and associated outcomes. NRHG may contribute to the formulation of a roadmap for hemoglobinopathies in Europe and promote the implementation of effective public health policies.

Role of Genomic Biomarkers in Increasing Fetal Hemoglobin Levels Upon Hydroxyurea Therapy and in ß-Thalassemia Intermedia: A Validation Cohort Study.

Hemoglobinopathies exhibit a remarkable phenotypic diversity in terms of disease severity, while individual genetic background plays a key role in differential response to drug treatment. In the last decade, genomic variants in genes located within, as well as outside the human ß-globin cluster have been shown to be significantly associated with Hb F increase, in relation to hydroxyurea (HU) therapy in patients with these diseases. Here, we aim to determine the effect of genomic variants located in genes, such as MAP3K5, ASS1, NOS2A, TOX, PDE7B, NOS1, FLT1 and ARG2, previously shown to modulate fetal hemoglobin (Hb F) levels in patients with ß type hemoglobinopathies and reflecting disease severity and response to HU therapy in an independent cohort of Greek patients with these diseases. We recruited and genotyped 45 ß-thalassemia patients (ß-thal), either transfusion-dependent (TDT) or non transfusion-dependent (NTDT), 42 Hb S (HBB: c.20A>T)-ß-thal compound heterozygotes, who were treated with HU, as well as 53 healthy individuals, all of Hellenic origin. Our study showed that genomic variants of the MAP3K5, NOS2A and ARG2 gene are associated with HU therapy efficacy in Hb S-ß-thal compound heterozygotes. We have also shown that FLT1 and ARG2 genomic variants are associated with the mild phenotype of NTDT patients. Our findings provide evidence that MAP3K5, NOS2A, ARG2 and FLT1 genomic variants could be considered as genomic biomarkers to predict HU therapy efficacy in Hb S-ß-thal compound heterozygotes and also to describe disease severity in patients with ß type hemoglobinopathies.

First Report of a Coincidental Discovery of Hb Shimonoseki [α54(E3)Gln→Arg, HBA2: c.164A > G (or HBA1)] in a Greek Family.

The rare Hb Shimonoseki [α54(E3)Gln→Arg, HBA2: c.164A > G (or HBA1)] has been reported in Western Japan. Hb Shimonoseki seems to be an innocuous variant and few published data are available. Heterozygous carriers have no clinical or hematological findings. The abnormal hemoglobin (Hb) was detected by high performance liquid chromatography (HPLC) and classic electrophoresis or capillary electrophoresis (CE), but confirmation of the variant is based on molecular studies. This is the first description of Hb Shimonoseki heterozygosity in a Greek family.

Insulin Secretion and Resistance in Normoglycemic Patients with Sickle Cell Disease.

Diabetes mellitus has been described in chronic hemolytic anemias, but data are scarce regarding glucose metabolism in normoglycemic patients. To address this issue, we evaluated insulin sensitivity and secretion in patients with sickle cell disease (SCD) and normal oral glucose tolerance test (OGTT). Forty-five adult patients with homozygous sickle cell disease and Hb S/ß-thalassemia (ß-thal) (mean age 42.5 ± 9.5 years) and 45 healthy individuals matched for age and body mass index (BMI) were included in the study. All participants underwent an oral glucose tolerance test (OGTT) after an overnight fast. All patients had normal OGTT. Fasting glucose values did not differ significantly between groups, however, fasting insulin levels were significantly lower in the patient group compared to the control group (5.1 ± 2.7 µUI/mL vs. 11.3 ± 6.6 µUI/mL, p <0.005, respectively). Pancreatic ß-cell insulin secretion index in the fasting state was significantly lower in patients with sickle cell disease compared with controls as assessed by calculations of the homeostatic model assessment for ß-cell function (HOMA ß%) (77.0 vs. 106.0%, respectively, p <0.001), while HOMA insulin resistance (HOMA IR), was lower in the sickle cell disease patients, albeit not statistically significant (0.8 vs. 1.1, respectively, p = 0.054). The HOMA ß% was significantly correlated with ferritin levels (r = -526, p <0.001) (negative correlation) and with 25-hydroxy (OH)-vitamin D levels (r = 0.479, p <0.001) (positive correlation), even when adjusted for serum ferritin levels. Normoglycemic patients with sickle cell disease demonstrated impaired ß-cell function with reduced insulin secretion even before OGTT was impaired.

Genomic variants in members of the Krüppel-like factor gene family are associated with disease severity and hydroxyurea treatment efficacy in ß-hemoglobinopathies patients.

Aim: ß-Type hemoglobinopathies are characterized by vast phenotypic diversity as far as disease severity is concerned, while differences have also been observed in hydroxyurea (HU) treatment efficacy. These differences are partly attributed to the residual expression of fetal hemoglobin (HbF) in adulthood. The Krüppel-like family of transcription factors (KLFs) are a set of zinc finger DNA-binding proteins which play a major role in HbF regulation. Here, we explored the possible association of variants in KLF gene family members with response to HU treatment efficacy and disease severity in ß-hemoglobinopathies patients. Materials & methods: Six tag single nucleotide polymorphisms, located in four KLF genes, namely KLF3, KLF4, KLF9 and KLF10, were analyzed in 110 ß-thalassemia major patients (TDT), 18 nontransfusion dependent ß-thalassemia patients (NTDT), 82 sickle cell disease/ß-thalassemia compound heterozygous patients and 85 healthy individuals as controls. Results: Our findings show that a KLF4 genomic variant (rs2236599) is associated with HU treatment efficacy in sickle cell disease/ß-thalassemia compound heterozygous patients and two KLF10 genomic variants (rs980112, rs3191333) are associated with persistent HbF levels in NTDT patients. Conclusion: Our findings provide evidence that genomic variants located in KLF10 gene may be considered as potential prognostic biomarkers of ß-thalassemia clinical severity and an additional variant in KLF4 gene as a pharmacogenomic biomarker, predicting response to HU treatment.

Arterial Stiffness and Peripheral and Central Blood Pressure in Patients With Sickle Cell Disease.

Blood pressure (BP) in patients with sickle cell disease (SCD) has been reported to be lower than in persons in the general population. Data on arterial stiffness, which is an important risk factor for the progression of BP, are inconclusive for this patient population. Forty-five adult patients with SCD and 40 controls matched for sex, age, and body mass index were studied. Brachial systolic BP (SBP) and diastolic BP (DBP) were significantly lower in the patient group (SBP 115.1±13.8 mm Hg vs 121.9±11.3 mm Hg and DBP 68.5±8.0 mm Hg vs 80.6±9.1 mm Hg, P<.05, respectively). Augmentation index (AIx), however, was significantly higher in SCD patients compared with healthy controls (24.9±9.6 for patients vs 12.4±10.8 for controls, P<.001), while carotid femoral pulse wave velocity was comparable between the two groups. The study shows that mechanisms other than arterial elasticity are involved in the low BP phenotype of patients with SCD.

Response of biochemical markers of bone turnover to oral glucose load in diseases that affect bone metabolism.

OBJECTIVE: Postprandial suppression of bone resorption is considered one of the main contributors in the circadian rhythm of bone turnover markers. The aim of this study was to investigate this physiological response of bone tissue in diseases that affect bone metabolism. PATIENTS AND METHODS: In this study, 118 patients (45 hypothyroid, 40 hyperthyroid, and 33 ß-thalassemic patients) and 78 healthy individuals matched for age and body mass index were included. An oral glucose test (75 g glucose) was performed after overnight fasting. Serum levels of procollagen type-I N-terminal propeptide (P1NP), ß-C-terminal telopeptide of type I collagen (ß-CTX), and osteocalcin were assayed at 0, 60, and 120 min. RESULTS: Baseline values of bone turnover markers were significantly elevated in hyperthyroid and ß-thalassemic patients but not in hypothyroid patients compared with the control group. After oral glucose, the levels of ß-CTX but not P1NP or osteocalcin were significantly suppressed in all groups (mean change from baseline is 46.9% for ß-CTX, 7.9% for P1NP, and 8% for osteocalcin). The percentage change from baseline for ß-CTX was significantly augmented in hypothyroidism (52 vs 42%, P=0.009). CONCLUSION: The preservation or even augmentation of postprandial suppression of bone resorption in diseases that affect bone metabolism through distinct pathogenetic mechanisms suggests the importance of this physiological response to nutrients for the general homeostasis and functional integrity of the skeleton.

Pregnancy in beta-thalassemia trait carriers: an uneventful journey.

Normochromic normocytic anemia during pregnancy reflects the significant increase in plasma volume, which disproportionately exceeds the increase in the red cell volume. In beta-thalassemia (beta-thal) trait carriers who become pregnant the plasma volume expansion may cause more pronounced anemia because the anemia of pregnancy is added to the pre-existed hypochromic microcytic anemia. In beta-thal women, pregnancy outcome and obstetric complications do not differ from the general population. Anemia in beta-thal carriers is generally not severe enough to warrant anxiety. No specific therapy is indicated and pregnant women generally require only supportive care with an anticipated favorable pregnancy outcome.

Amifostine stimulates the formation of hematopoietic bone marrow progenitors from B-cell chronic lymphocytic leukemia.

Amifostine is a phosphorylated aminothiol that not only protects hematopoietic progenitor cells from chemotherapy and radiotherapy, but also stimulates normal hematopoiesis. The effect of amifostine on the in vitro growth of hematopoietic progenitors derived from B-cell chronic lymphocytic leukemia(B-CLL) was investigated. The colony-forming units (CFU)-granulocyte macrophage (CFU-GM), the burst-forming units-erythroid (BFU-E) and the CFU-granulocyte erythroid macrophage megakaryocytes (CFU-GEMM) increased 38, 20 and 100%, respectively, after the incubation with amifostine. There was no statistical difference in the in vitro progenitor growth of patients grouped according to their disease stage, bone marrow lymphocytic infiltration or therapy. Our data indicate that apart from cytoprotection the parallel use of amifostine and chemotherapy in patients with B-CLL could enhance bone marrow recovery.