Plans: Project 8 investigators are conducting abundance proteome studies of endothelial progenitor cells.<\/p>\n
Progress: Researchers developed procedures to reproducibly isolate endothelial progenitor cells (EPC) from human and mouse sources. They also performed a number of studies to assess their biological properties. Of particular relevance, one of the studies analyzed the effects of oxidative stress on EPC biology. The effect of vascular oxidant stress on ischemia-induced neovascularization was tested in a murine model of homozygous deficiency of GPx-1. GPx-1-deficient mice showed impaired revascularization following hind limb ischemic surgery based upon laser Doppler measurements of blood flow and capillary density in adductor muscle. GPx-1-deficient mice also showed an impaired ability to increase EPC levels in response to ischemic injury or subcutaneous administration of VEGF protein. EPCs isolated from GPx-1-deficient mice showed a reduced ability to neutralize oxidative stress in vitro, that was associated with impaired migration toward VEGF and increased sensitivity to ROS-induced apoptosis. EPCs isolated from GPx-1-deficient mice were impaired in their ability to promote angiogenesis in wild-type mice, whereas wild-type EPCs were effective in stimulating angiogenesis in GPx-1-deficient mice. These data suggest that EPC dysfunction is a mechanism by which elevated levels of ROS can contribute to vascular disease. A manuscript describing this study was submitted for publication.<\/p>\n
In another study, angiogenesis in a mouse model of diabetes and obesity was analyzed. Diabetes and obesity are risk factors for the development of cardiovascular diseases that are associated with elevated oxidative stress. Angiogenic repair of ischemic hind limbs was impaired in diabetic, obese Leprdb\/db mice compared to wild-type C57BL\/6 (WT) mice as evaluated by laser Doppler flow and capillary density analyses. To identify molecular targets associated with this disease process, hind limb cDNA expression profiles were created from adductor muscle of Leprdb\/db and WT mice before and after hind limb ischemia using Affymetrix GeneChip\u00ae Mouse Expression Set microarrays. To analyze these data, researchers employed an automated analysis of related transcripts using Ingenuity Pathways Analysis software. For this analysis, a set of 3128 transcripts differentially expressed in WT mice at day 14 compared to baseline (pre-surgery), was used as the starting point for generating biological networks. This analysis revealed that the expression patterns of numerous angiogenesis-related proteins were altered in Leprdb\/db versus WT mice following ischemic injury. The transcripts included neuropilin-1, VEGF-A, placental growth factor, elastin and matrix metalloproteinases that are implicated in blood vessel growth and maintenance of vessel wall integrity. Collectively, these data showed that impaired ischemia-induced neovascularization in type 2 diabetes is associated with the dysregulation of a complex angiogenesis regulatory network. This work was published in Impaired revascularization (S. Scheikofer et al.),<\/a> Arterioscler Thromb Vasc Biol<\/em>, August 2005.<\/p>\n