Transgenic sickle mice have vascular inflammation

Inflammation may play an essential role in vaso-occlusion in sickle cell disease. Sickle patients have high white counts and elevated levels of serum G-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 less than or equal to .01) in the Berk-S-Antilles, Ny-S/S-Antiller, and Berk-S mice, but not in the NY-S mice compared with controls. Serum amylold P-component (SAP), an acute-phase response protein with 60% to 70% sequence homology to CRP, was elevated 8.5- to 12.1-fold (P less than or equal to .001) in transgenic sickle mice. Similarly, serum interleukin-6 (IL-6) was elevated 1.6- to 1.9-fold (P less than or equal to .05). Western blots, confirming immunohistochemical staining, showed vascular cell adhesion molecule (VCAM), intercellular adhesion molecule (ICAM), and platelet-endothelial cell adhesion molecule (PECAM) were up-regulated 3- to 54old (P less than or equal to .05) in the lungs of sickle mice. Ribo-nuclease protection assays (RPAs) demonstrated VCAM mRNA also was elevated in sickle mice 1.2- to 1.4-fold (P less than or equal to .01). Nuclear factor kappaB (NF-kappaB), a transcription factor critical for the inflammatory response, was elevated 1.9-fold (P less than or equal to .006) in NY-S sickle mouse lungs. We conclude that transgenic sickle mice are good models to study vascular inflammation and the potential benefit of anti-inflammatory therapies to prevent vaso-occlusion in sickle cell disease. (C) 2003 by The American Society of Hematology.