The Effect of Mechanical Compatibility and of Thrombogenicity on the Ingrowth of a New Synthetic Vascular Prosthesis (Experimental Study).

Common disadvantages of modern synthetic vascular prostheses are thrombogenicity and lack of biomechanical compatibility with the prothesized vessel. To elucidate the role of these factors in the prosthesis integration, prostheses specimens were made by the electrospinning from the known materials: polycaprolactone, polyurethane and a mixture of fluorine-containing synthetic rubber FKM-26 with fluoroplastic F-26. The germination of the prostheses was compared with standard e-PTFE prosthesis in the pigs infrarenal aorta. The elastic properties of prostheses were studied by elastometry under the physiological range of loads. The thrombogenicity of the materials was determined by the number of platelets adhered to material surface exposed to native blood. The patency of the prostheses was checked by aortography. The germination of prostheses was assessed in the histological examination. It was shown that, with this set of materials, biomechanical compatibility turned out to be a more important factor of integration than the material thrombogenicity.

Peculiarities of Cell Seeding on Electroformed Polycaprolactone Scaffolds Modified with Surface-Active Agents Triton X-100 and Polyvinylpyrrolidone.

We compared the capability of human fibroblasts to populate porous polycaprolactone (PCL) scaffolds modified during fabrication with surface-active agents Triton Ð¥-100 (type 1 scaffold) and polyvinylpyrrolidone (type 2 scaffold). The mean fiber diameter in both scaffolds was almost the same: 3.90±2.19 and 2.46±2.15 µ, respectively. Type 1 scaffold had higher surface density and hydrophilicity, when type 2 scaffold was 1.6 times thicker. The cells were seeded on the scaffolds by the dynamic seeding technique and then cultured in Petri dishes with nutrient medium in a humid atmosphere. During 3-day culturing, no cell release from the matrix was noted. DAPI staining proved the presence of cells in both scaffolds. However, in type 1 scaffold the cells populated the whole thickness, while in type 2 scaffold, the cells were present only in the superficial layer. These findings suggest that PCL scaffolds modified with Triton Ð¥-100 or polyvinylpyrrolidone are not cytotoxic, but the structure of the scaffold treated with Triton Ð¥-100 is more favorable for population with cells.

Proliferative and Differentiation Potential of Multipotent Mesenchymal Stem Cells Cultured on Biocompatible Polymer Scaffolds with Various Physicochemical Characteristics.

Biocompatibility of film and fibrous scaffolds from polylactide-based polymers and the relationship between their architecture and the functional characteristics of mesenchymal stem cells were studied. Cell culturing on polylactide-based film and fibrous matrixes did not deteriorate cell morphology and their proliferation and differentiation capacities. The rate of cell proliferation and penetration in microporous 3D matrices with the same porosity parameters and pore size depended on their spatial organization. The above materials can be used as scaffolds for mesenchymal stem cells for creation of tissue engineering implants. The scaffold size and structure should be determined by the defects in the organs in which the regeneration processes have to be stimulated.

Migration and Proliferative Activity of Mesenchymal Stem Cells in 3D Polylactide Scaffolds Depends on Cell Seeding Technique and Collagen Modification.

We analyzed viability of mesenchymal stem cells seeded by static and dynamic methods to highly porous fibrous 3D poly-L-lactide scaffolds with similar physical and chemical properties, but different spatial organization modified with collagen. Standard collagen coating promoted protein adsorption on the scaffold surface and improved adhesive properties of 100 µ-thick scaffolds. Modification of 600-µ scaffolds with collagen under pressure increased proliferative activity of mesenchymal stem cells seeded under static and dynamic (delivery of 100,000 cells in 10 ml medium in a perfusion system at a rate of 1 ml/min) conditions by 47 and 648%, respectively (measured after 120-h culturing by MTT test). Dynamic conditions provide more uniform distribution of collagen on scaffold fibers and promote cell penetration into 3D poly-L-lactide scaffolds with thickness >600 µ.

Biocompatibility of Experimental Polymeric Tracheal Matrices.

Biocompatibility of a new tracheal matrix is studied. The new matrix is based on polymeric ultra-fiber material colonized by mesenchymal multipotent stromal cells. The experiments demonstrate cytoconductivity of the synthetic matrices and no signs of their degradation within 2 months after their implantation to recipient mice. These data suggest further studies of the synthetic tracheal matrices on large laboratory animals.