Characterization of circulatory disorders in beta-thalassemic mice by noninvasive ultrasound biomicroscopy

Beta-thalassemia is an inherited hematological disease caused by a decrease or absence of production of beta-globin that requires chronic therapeutic interventions. This condition leads to important arterial and venous thromboembolic events, transitory ischemic attacks, and microcirculatory obstructions, indicative of circulatory disturbances. To investigate the presence of microcirculatory disorders without the confounding effect of treatments, we used beta-thalassemic mice with typical clinical characteristics of human beta-thalassemia major. One impediment to the understanding of microcirculatory physiology, in particular for beta-thalassemic mice, has been the lack of an appropriate noninvasive imaging approach. We thus developed a novel noninvasive high-frequency ultrasound imaging method to evaluate murine vascular hemodynamic properties. In our beta-thalassemic mice, total peripheral vascular resistance was significantly increased (P < 0.01) compared with wildtype littermates, whereas mean blood pressure, heart rate, and cardiac output were similar (P = nonsignificant). Importantly, the vascular hemodynamics in beta-thalassemic mice were significantly affected according to the Pourcelot indexes measured in the common carotid artery and abdominal aorta (P < 0.01 and P < 0.05, respectively). Hence, our beta-thalassemia characterization of vascular hemodynamics by noninvasive ultrasonic approaches proves the existence and provides unique quantitative assessment of microcirculatory flow disturbances in those mice.