In vivo vascular tissue engineering: influence of cytokine and implant location on tissue specific cellular recruitment

In vivo tissue engineering has been explored as a means to create autologous vascular replacements. Elastin is necessary to sustain continual pulsatile flow and to prevent the dilatation of vascular tissues. Unfortunately, elastogenesis in tissue-engineered constructs has been very limited. To overcome this limitation, we have created tubular elastin scaffolds from porcine carotid arteries. Elastin would provide the necessary elasticity to the graft on implanting these scaffolds as vascular grafts. In this study, elastin tubes with agarose gel containing either stromal-derived factor-1 alpha [SDF; for homing of endothelial cells (ECs)] or basic fibroblast growth factor (bFGF; for homing of myofibroblasts) were implanted into adipose tissue, as it is a known source of stem/progenitor cells. We also implanted these tubes into subdermal pouches (as a control location). We observed a difference in the types of cells recruited - ECs were recruited in large numbers by SDF in the adipose tissue, whereas the adipose-FGF group had a vascularized (smooth muscle and EC-positive), collagenous capsule (adventitia) with many smooth muscle alpha-actin (SMA)-positive cells in the elastin scaffold layer (media). These results were in contrast to the subdermal group, which only recruited fibroblasts and some SMA-positive cells. Also, more cell infiltration and neo-collagen formation was seen in adipose implants. This study provides novel results by the use of specific cytokines and implant locations to recruit tissue-specific cells to create autologous vascular grafts. Copyright (c) 2009 John Wiley & Sons, Ltd.