Direct cell seeding on collagen-coated silicone mandrels to generate cell-derived tissue tubes

Doshi, Kshama J

Etd

Direct cell seeding on collagen-coated silicone mandrels to generate cell-derived tissue tubes

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The large number of patients suffering from cardiovascular diseases has led to a high demand for functional arterial replacements. A variety of approaches to vascular graft tissue engineering have shown promise, including seeding cells onto natural and synthetic scaffolds or by culturing cell sheets which are subsequently rolled into a tube without exogenous scaffolds. The goal of this project is to develop and characterize cell-derived, fully biological small diameter tissue engineered tubes by seeding and culturing cells directly on tubular supports. Rat aortic smooth muscle cells were seeded onto collagen-coated silicone mandrels and cultured for 14 days. Cells proliferated on the mandrels to form tubes (1.19 mm inner diameter, 1.68 +/- 0.1 mm outer diameter and 230 +/- 63 microns thick; n=72). Histological analysis of the developed tissue tubes demonstrated circumferential alignment of smooth muscle cells, abundant glycosaminoglycan production and some amount of collagen production. On inflating at a constant rate, it was observed that the tissue tubes dilated to an average burst pressure of 256 +/- 76 mmHg; (n=11). In order to observe the effects of addition of soluble factors on extracellular matrix synthesis and mechanical properties, tissue tubes were grown in culture medium supplemented with 50 microgram/ml sodium ascorbate. A significant decrease in outer diameter and wall thickness (1.57 +/- 0.02 mm and 189 +/- 10 microns; n=6 respectively) in the treated groups was observed as compared to (1.66 +/- 0.06 mm and 234 +/- 32 microns; n=6; p<0.05) for the untreated control groups. A slight increase in collagen production was observed by visual assessment of histological images of the ascorbate-treated tissue tubes. This suggests that by using a direct cell seeding approach, it is possible to develop completely biologic small diameter cell-derived tissue tubes that can withstand handling, and it may also possible to modulate matrix synthesis by optimizing cell culture conditions.

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