Glutathione S-transferase gene polymorphism: Relation to cardiac iron overload in Egyptian patients with Beta Thalassemia Major.

OBJECTIVES: Estimating the prevalence of glutathione S-transferase gene polymorphism (GSTM1) null genotype among patients with beta thalassemia major (ß-TM) in relation to myocardial status assessed by tissue Doppler and cardiac siderosis assessed by cardiac magnetic resonance imaging (MRI) T2*. METHODS: Hundred patients with ß-TM and 100 healthy controls were enrolled. Complete blood count (CBC), mean serum ferritin and GSTM1 genotyping, echocardiography, tissue Doppler, and cardiac MRI T2* were done. RESULTS: Serum ferritin ranged from 1200 to 8000 ng/ml, and mean T2* value was 27.10 ± 11.20 ms. Of patients, 68 (68%) had no cardiac siderosis, while 24 (24%) with mild to moderate, and 8 (8%) with sever cardiac siderosis. T2* values were not correlated with serum ferritin (r = -0.09, P = 0.50). GSTM1 null genotype was prevalent in 46% of patients and 40% of controls (P = 0.69). Patients with null genotype had significantly shorter T2* (P = 0.001), higher left ventricular end-diastolic diameter (P = 0.002), and shorter ejection time (P = 0.005) with no significant relation to serum ferritin (P = 0.122). GSTM1 null genotype was the only predictor for cardiac iron overload (P = 0.002). DISCUSSION: Serum ferritin concentrations have been shown to correlate poorly with all stages of cardiac dysfunction. Low cardiac MRI T2* values occur in patients with ß-TM despite good chelation therapy, suggesting a possible role of genetic factors in cardiac siderosis. CONCLUSION: GSTM1 null genotype is significantly associated with cardiac iron overload independent of serum ferritin in Egyptian patients with ß-TM.

Flow cytometric assessment of circulating platelet and erythrocytes microparticles in young thalassemia major patients: relation to pulmonary hypertension and aortic wall stiffness.

Heart disease is the leading cause of mortality and morbidity in ß-thalassemia major (ß-TM). Aggregability of abnormal red cells and membrane-derived microparticles (MPs) stemming from activated platelets and erythrocytes are responsible for thrombotic risk. We measured platelet and erythrocyte MPs (PMPs and ErMPs) in 60 young ß-TM patients compared with 40 age- and sex-matched healthy controls and assessed their relation to clinicopathological characteristics and aortic elastic properties. Patients were studied stressing on transfusion history, splenectomy, thrombotic events, chelation therapy, hematological and coagulation profiles, flow cytometric measurement of PMPs (CD41b(+) ) and ErMPs (glycophorin A(+) ) as well as echocardiographic assessment of aortic elastic properties. Aortic stiffness index and pulmonary artery pressure were significantly higher, whereas aortic strain and distensibility were lower in TM patients than controls (P < 0.001). Both PMPs and ErMPs were significantly elevated in TM patients compared with controls, particularly patients with risk of pulmonary hypertension, history of thrombosis, splenectomy or serum ferritin >2500 µg/L (P < 0.001). Compliant patients on chelation therapy had lower MPs levels than non-compliant patients (P < 0.001). PMPs and ErMPs were positively correlated to markers of hemolysis, serum ferritin, D-dimer, vWF Ag, and aortic stiffness, whereas negatively correlated to hemoglobin level and aortic distensibility (P < 0.05). We suggest that increased MPs may be implicated in vascular dysfunction, pulmonary hypertension risk, and aortic wall stiffness observed in thalassemia patients. Their quantification could provide utility for early detection of cardiovascular abnormalities and monitoring the biological efficacy of chelation therapy.