Fabrication of tissue-engineered vascular grafts using low sustained intraluminal pressure to sod human adipose-derived stromal vascular fraction cells onto ePTFE

Abstract

Every year millions of Americans are affected by cardiovascular and peripheral arterial diseases. When a patient’s own blood vessels are not suitable for surgical intervention, alternative graft sources are necessary. In this study, the lumens of expanded polytetrafluoroethylene (ePTFE) conduits were coated with freshly isolated adipose-derived stromal vascular fraction (SVF) cells or cultured adipose-derived stromal cells (ASCs) by a single-stage method called “pressure sodding,” using low sustained intraluminal pressure. ePTFE vascular conduits were sodded in as short as 5 minutes. The luminal surface coverage of grafts immediately following pressure sodding and subsequent exposure to physiological luminal flow was evaluated by nuclear staining of the attached cells to the conduit. Cell behavior associated with the sodding process and subsequent shear stress via luminal flow was examined through tissue factor quantification. After exposure to luminal flow at a rate approximating physiological shear in human coronary arteries, the sodded cells remained on the ePTFE conduits. When cultured SVF cells (ASCs, attached stromal cells) were used, average normalized tissue factor levels increased with the application of a luminal flow following the cell sodding process. However, when freshly isolated SVF cells were used, the average normalized tissue factor did not significantly change even after luminal flow. When these cell-coated vascular grafts were implanted into the carotid arteries of dogs, they remained patent for at least 140 days. This novel method of pressure sodding is critical to rapid fabrication of tissue-engineered vascular grafts which can facilitate a successful point-of-care treatment for a number of vascular diseases.