Publication Date:
2010-11-19
Description:
Abstract 944 Acute chest syndrome (ACS) is the leading cause of death among patients with sickle cell disease (SCD). It is a process of devastating acute lung injury that evolves from multiple exacerbating events including vaso-occlusive pain crises, infection and fat emboli. ACS results in pulmonary infiltration, hypoxemia, and occlusions in the pulmonary microcirculation. Hitherto, experimental models of ACS have been lacking, and molecular targets of therapy remain to be identified. Clinical studies indicate that most patients diagnosed with ACS hemolyse during the acute phase of the syndrome, which highlights a role for circulating heme/hemin in this process. Since the deleterious effects of hemin are defined by increased vascular permeability, we tested the hypothesis that acute elevation of circulating hemin would increase pulmonary microvascular leakage sufficiently to trigger ACS. Adult transgenic mice expressing exclusively human sickle hemoglobin (Hb SS), and control Hb AS and Hb AA mice were intravenously injected with hemin (70 micromoles/kg body weight), and cardiopulmonary function assessed in real-time using a mouse pulse oximeter. Arterial oxygen saturation (SpO2) in the SS mice reduced significantly (p = 0.02) to 84.1 ± 5.6 % from a normal baseline value of 98.6 ± 0.3 %, within 25 minutes of administration of i.v. hemin, while SpO2 in control AS and AA mice remained unchanged. Consistent with changes in cardiopulmonary function, all the SS mice (n=14) succumbed to hemin, within 2 hours, while all control AS and AA mice survived, and remained alive several weeks after the experiment (log-rank survival test, p=
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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