Preparation of Biotubes with vascular cells component by in vivo incubation using adipose-derived stromal cell-exuding multi-microporous molds.

Biotubes, prepared using in-body tissue architecture (IBTA) technology, have adequate mechanical properties and excellent biocompatibility for vascular grafts. However, they have thin walls, lack vascular constructing cells, and are composed of subcutaneous connective tissues consisting mainly of collagen and fibroblasts. This study aimed to prepare Biotubes with a vascular-like structure including an endothelial cell lining and a smooth muscle cell by IBTA using adipose-derived vascular stromal cell (ADSCs)-exuding specially designed multiporous tubes (outer diameter 5 mm, length 24 mm, pore size 500 μm, pore number 180, cell number/tube >3.0 × 10(6)). ADSCs were separated from rat subcutaneous fat, suspended in a Matrigel™ solution at 4 °C, and then filled into the tubes. After the tubes were embedded into dorsal subcutaneous pouches of the same rats for 2 weeks, robust Biotubes with a wall thickness of >600 μm were formed surrounding the tubes. The luminal layer of the obtained Biotubes was dominated by the cells positive for an endothelial marker. Almost the entire intima, with a thickness of about 400 μm, was occupied with cells positive for a smooth muscle marker. Both cells were derived from ADSCs. Biotube walls were constructed by fusing ADSC-derived vascular constructing cells exuded from the tubes and fibroblasts and collagen from the surrounding connective tissue. A robust Biotubes with vascular cells component, were formed after only 2 weeks of subcutaneous incubation of ADSCs-exuding multiporous tubes.