Abstract 199: Adipose-Derived Stem Cells from Diabetic Patients Undergo Endothelial Differentiation for Use in the Creation of a Tissue-Engineered Vascular Graft

INTRODUCTION: Surgical bypass and dialysis access creation are common procedures performed in diabetic patients. Only 55% of patients have autologous vascular tissue available for use as a conduit in these operations. We have developed an alternative conduit composed of a vascular scaffold seeded with autologous adipose-derived stem cells (ASC) differentiated into endothelial cells (EC) to create a non-thrombogenic lumen. OBJECTIVE: To examine ASC from diabetic (DM) versus non-diabetic (NDM) patients in terms of isolation efficiency, proliferation, commitment towards EC lineage, and seeding onto a vascular scaffold. METHODS: ASC were isolated from peri-umbilical liposuction specimens by collagenase dispersion (DM n=53; NDM n=145). Isolation efficiency was defined by number of ASC isolated per gram of adipose tissue. Proliferation was assessed by constructing growth curves over 14d. ASC were differentiated in endothelial growth medium for 3wk. Differentiation was determined by measuring EC-specific gene expression (CD31, vWF) using qPCR. Lastly, ASC were seeded onto decellularized vein, flow conditioned from 0-9 dynes over 5d, and examined using confocal microscopy. RESULTS: ASC isolation efficiency did not differ between DM and NDM patients (224,028 cells/gm vs. 259,345 cells/gm, respectively; P=0.21). The growth curves for DM (n=6) and NDM (n=6) ASC also appeared similar, with no significant differences observed in cells counts between days 1-14. After 1, 2, and 3wk in culture, no significant difference in CD31 or vWF expression between DM (n=6) and NDM (n=6) cells was observed. Finally, retention of ASC to vascular scaffolds under physiological shear stress was similar between the two groups. CONCLUSIONS: ASC are isolated from DM in quantities similar to those observed in NDM. These cells grow at rates similar to NDM ASC, exhibit differentiation into an EC phenotype, and line the lumen of a tissue engineered vascular graft. These results suggest that adipose tissue may prove to be a more reliable source of autologous stem cells than blood or bone marrow, where the presence of diabetes and other co-morbidities significantly decrease the availability of stem cells for use in regenerative therapies.