Hydroxyurea-induced denaturation of normal and sickle cell hemoglobins in vitro

Use of hydroxyurea (HU) to treat sickle cell disease is usually associated with increments in fetal hemoglobin (Hb F) production; however, in vitro studies show that HU may also induce hemoglobin denaturation. Whole blood samples from Hb AA, Hb AS, and Hb SS patients were treated in vitro with 100, 150, 200, 250, and 300 μg/mL HU, incubated at 30°C for up to 12 days, and analyzed by high-performance liquid chromatography (HPLC). Hb AA levels show decrements of 91 to 14% with 100 μg/mL and 89 to 4% with 150 μg/mL after 12 days; 86 to 2% with 200 μg/mL after 10 days; 86 to 8% with 250 and 300 μg/mL after 8 days. Similar treatment and incubation times for Hb AS whole blood demonstrate that HU equally degrades the A and S components of Hb AS. A comparable approach for Hb SS whole blood samples, using a 300 μg/mL HU treatment, showed a hemoglobin denaturing pattern that went from 93% to 1% after 12 days. Globin chain analysis of these samples by reverse-phase HPLC showed that the denaturing effects occur mostly on the β-globin chain. J. Clin. Lab. Anal. 11:208–213, 1997. © 1997 Wiley-Liss, Inc.