Novel Microfluidic Approaches to Define Diabetic Progenitor Cell Dysfunction
Geoffrey Gurtner   (Stanford, CA)
Diabetes-induced impairments in new blood vessel growth greatly increase the severity of wound healing and ischemic processes, including coronary artery disease, cerebrovascular disease, and peripheral vascular disease. Bone marrow (BM) derived vascular progenitor cells are believed to play a critical role in ischemic neovascularization, and may have considerable therapeutic potential as cell-based vectors for the repair of vascular injury. However, the specific lineage of these cells, termed endothelial progenitor cells (EPCs), remains unclear. Early clinical trials using BM-derived cells have yielded disappointing and discordant results, suggesting the need for further characterization. Mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) are considered the two most likely candidate sources, but overlap among definitions, as well as considerable heterogeneity intrinsic to these populations, has complicated their evaluation. We have previously demonstrated in vivo and in vitro dysfunction of specific MSC populations using murine models of diabetes. However, overcoming the heterogeneity inherent to such populations will ultimately require transcriptional analysis of individual cells. To achieve this we have developed a novel method for high-throughput single cell analysis employing microfluidic technology. This proposal seeks to apply that technique to further characterize HSC and MSC populations, using diabetes as a phenotypic marker of disease, to evaluate vasculogenic potential and identify specific diabetes-induced alterations. In Specific Aim 1, we develop a quantitative measure of population heterogeneity and apply it to evaluate HSCs and MSCs from the BM of wild-type (WT) and diabetic mice. A novel partitive analysis is applied in Specific Aim 2 to detect discrete MSC subpopulations and generate characteristic expression profiles. Specific Aim 3 extends these studies to evaluate the transcriptional response of individual subpopulations to peripheral tissue ischemia.