Sensitivity of Sickle Erythrocytes to Hemolysis

Gadolinium (Gd), an element that possesses a character similar to that of calcium or magnesium, is known to have a strong hemolytic effect on erythrocytes (RBC) at even very low concentrations. 3, 5 One of the major characteristics of sickle cell disease is hemolysis of the abnormal RBC. Therefore, concerns have been raised that Gadolinium, as an MRI contrast agent for clinical use, should not be used in patients with sickle cell disease due to the risk of increasing RBC hemolysis. However, these concerns regarding the detrimental effects of gadolinium seem to stem from data collected on elemental Gd and not the bound agent Gd-DPTA, chelated to diethylenetriaminepentaacetic acid (DTPA).7 Preliminary studies demonstrate minimal hemolysis of sickle RBC with GD-DTPA. "Sickling" is the phenomenon whereby the abnormal sickle hemoglobin undergoes polymerization when deoxygenated, giving rise to the typical sickled RBC shape. The abnormal RBC properties in sickle cell disease also include abnormal ion transport and decreased water content. The decreased water content may be protective against hemolysis by Gd and Gd-DTPA.8 We hypothesize that Gd-DTPA, the contrast agent used in MRI procedures, does not cause an increase in hemolysis of RBC from patients with sickle cell disease. This study examines the sensitivity of sickle cell disease. This study examines the sensitivity of sickle RBC to hemolysis using in vitro incubation with Gd-DTPA. We compare the degree of hemolysis of RBC from sickle cell patients with the hemolysis of RBC from normal controls. Experiments include incubation of RBC with GD-DTPA, control buffer, hyperosmolar solutions, or elemental Gd.