RESUMEN
Vascular inflammation, secondary to ischemia-reperfusion injury, may play an essential role in vaso-occlusion in sickle cell disease (SCD). To investigate this hypothesis, dorsal skin fold chambers (DSFCs) were implanted on normal and transgenic sickle mice expressing human alpha and beta(s)/beta(s-Antilles) globin chains. Microvessels in the DSFC were visualized by intravital microscopy at baseline in ambient air and after exposure to hypoxia-reoxygenation. The mean venule diameter decreased 9% (P < 0.01) in sickle mice after hypoxia-reoxygenation but remained constant in normal mice. The mean RBC velocity and wall shear rate decreased 55% (P < 0.001) in sickle but not normal mice after hypoxia-reoxygenation. None of the venules in normal mice became static at any time during hypoxia-reoxygenation; however, after 1 hr of hypoxia and 1 hr of reoxygenation, 11.9% of the venules in sickle mice became static (P < 0.001). After 1 hr of hypoxia and 4 hr of reoxygenation, most of the stasis had resolved; only 3.6% of the subcutaneous venules in sickle mice remained static (P = 0.01). All of the venules were flowing again after 24 hr of reoxygenation. Vascular stasis could not be induced in the subcutaneous venules of sickle mice by tumor necrosis factor alpha (TNF-alpha). Leukocyte rolling flux and firm adhesion, manifestations of vascular inflammation, were significantly higher at baseline in sickle mice compared to normal (P < 0.01) and increased 3-fold in sickle (P < 0.01), but not in normal mice, after hypoxia-reoxygenation. Plugs of adherent leukocytes were seen at bifurcations at the beginning of static venules. Misshapen RBCs were also seen in subcutaneous venules.
Asunto(s)
Anemia de Células Falciformes/fisiopatología , Daño por Reperfusión/fisiopatología , Piel/irrigación sanguínea , Anemia de Células Falciformes/sangre , Anemia de Células Falciformes/complicaciones , Anemia de Células Falciformes/genética , Animales , Recuento de Células Sanguíneas , Adhesión Celular/fisiología , Femenino , Hematócrito , Rodamiento de Leucocito , Leucocitos/citología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Microcirculación/fisiología , Microscopía/instrumentación , Microscopía/métodos , Daño por Reperfusión/sangre , Daño por Reperfusión/complicaciones , Reticulocitos/citologíaRESUMEN
Inflammation may play an essential role in vaso-occlusion in sickle cell disease. Sickle patients have high white counts and elevated levels of serum C-reactive protein (CRP), cytokines, and adhesion molecules. In addition, circulating endothelial cells, leukocytes, and platelets are activated. We examined 4 transgenic mouse models expressing human alpha- and sickle beta-globin genes to determine if they mimic the inflammatory response seen in patients. These mouse models are designated NY-S, Berk-S(Antilles), NY-S/S(Antilles) (NY-S x Berk-S(Antilles)), and Berk-S. The mean white counts were elevated 1.4- to 2.1-fold (P