Endothelial dysfunction in patients with hereditary spherocytosis and b-thalassemia

Abstract

Patients with hereditary spherocytosis and b-Thalassemia are characterized by the increased risk of thrombosis. The early manifestation of thrombotic complications can occur even in childhood especially after surgery. Hypercoagulability can be associated with endothelial dysfunction. The aim of this study was to investigate the hemostatic state and endothelial function in children with hereditary spherocytosis and b-thalassemia. The study was approved by the Independent Ethics Committee of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology. The hemostatic status of 18 children (10 boys and 8 girls from 1 to 13 years) with hereditary spherocytosis and of 8 children (4 boys and 4 girls from 3 to 8 years) with b-thalassemia was assessed using clotting times (activated partial thromboplastin time – APTT, thrombin time – TT, prothrombin time PT), fibrinogen levels and markers of endothelium dysfunction: endothelin-1 and thrombomodulin levels. Patients with hereditary spherocytosis were divided into 2 groups: during the hemolytic crisis (11 patients) and without the hemolytic crisis (7 patients). Patients with b-Thalassemia were divided into 3 groups: b-thalassemia major, b-thalassemia intermedia and b-thalassemia minor. APTT, TT and PT were not changed significantly between groups. We find the decreased fibrinogen levels in patients with severe condition: in hereditary spherocytosis patients during hemolytic crisis (1.9 ± 0.3 ng/ml with normal range 2–3.9 ng/ml) and in b-thalassemia major patients (1.8 ± 0.3 ng/ml with normal range 2–3.9 ng/ml). This could be caused by consumption of fibrinogen during acute hemolysis. The Thrombomodulin levels were increased in all hereditary spherocytosis patients, but median value was higher in group with hemolytic crisis (6665 pg/ml vs 5976 pg/ml with ormal value 275–909 pg/ml) indicating endothelium dysfunction and activation of blood clotting. In b-thalassemia patients Thrombomodulin levels were more elevated in b-thalassemia major and b-thalassemia intermedia (6389 ± 537 pg/ml и 6804 ± 120 pg/ml) compared to b-thalassemia minor (2727 ± 213 pg/ml) which is still higher than normal range. Endothelin-1 levels were elevated on 55% with hereditary spherocytosis patients during crisis vs 43% without. In general Endothelin-1 levels were more elevated in b-thalassemia patients (were normal in b-thalassemia minor) vs hereditary spherocytosis patients (2.33 ± 2.89 fmol/ml vs 0.95 ± 0.35 fmol/ml). Thrombomodulin and endothelin-1 levels revealed endothelium dysfunction in children with hemolysis. More dramatic changes observed in severe condition: in hereditary spherocytosis patients during hemolytic crisis and in b-thalassemia major and b-thalassemia intermedia patients.