A Technology for Anti-Thrombogenic Drug Coating of Small-Diameter Biodegradable Vascular Prostheses.

The aim of the study was to develop a technology for anti-thrombogenic drug coating of biodegradable porous scaffolds and to evaluate the physicomechanical and hemocompatible properties of functionally active vascular prostheses with and without a drug coating. MATERIALS AND METHODS: Vascular prostheses from polyhydroxybutyrate/valerate and polycaprolactone with the incorporated vascular endothelial growth factor, the main fibroblast growth factor, and the chemoattractant SDF-1α were made by emulsion electrospinning. Additional surface modification of the prostheses was carried out by forming a hydrogel coating of polyvinylpyrrolidone capable of binding drugs as a result of complexation. Unfractionated heparin and iloprost were used as anti-thrombogenic drugs. RESULTS: We show that after the modification of vascular prostheses with heparin and iloprost, a 5.8-fold increase in the Young's modulus value was noted, which indicated a greater stiffness of these grafts compared to the unmodified controls. Platelet aggregation on the surface of heparin + iloprost coated vascular prostheses was 3.3 times less than that with the unmodified controls, and 1.8 times less compared to intact platelet-rich plasma. The surface of vascular prostheses with heparin and iloprost was resistant to adhesion of platelets and blood proteins. CONCLUSION: Drug (unfractionated heparin and iloprost) coating of the surface of biodegradable prostheses significantly improved the anti-thrombogenic properties of these grafts but contributed to the increased stiffness of the prostheses.

[Influence of unmodified and modified sutures on experimental abdominal adhesive process]. / Éksperimental'naia otsenka spaechnogo protsessa v briushnoi polosti pri ispol'zovanii nemodifitsirovannogo shovnogo materiala i modifitsirovannogo geparinom.

OBJECTIVE: Experimental assessment of the effect of modified and unmodified surgical suture material on abdominal adhesive process. MATERIAL AND METHODS: The study was performed on male rats of the Wistar subpopulation. There were 5 animals in each group. In all animals, midline abdominal incision was followed by suturing the parietal peritoneum with modified and unmodified suture material. All animals were euthanized with carbon dioxide vapors in 14 days after surgery. Macro- and microscopic assessment of severity of abdominal adhesive process was carried out. Two types of preparation of excised complexes 'peritoneum-suture material-adhesion' were applied for histological examination: paraffin sections and embedding in epoxy resin. Specimens were stained by Van Gieson and with methylene blue solution. Histological specimens were examined using Axio Imager A1 light microscope (Zeiss, Germany). RESULTS: Polypropylene filaments result extensive adhesions occupying about 75% of the area. Adhesions have a dense structure with signs of vascularization. Modification of suture material with solution of polyhydroxybutyrate/hydroxyvalerate and heparin reduce severity of adhesions. The use of modified suture material was followed by adhesions with more loose structure, no signs of vascularization. Adhesions occupied less than 25% of the area. Histological examination of excised complexes 'peritoneum-suture material-adhesion' revealed accumulation of inflammatory cells around the unmodified suture material, while there were no signs of tissue inflammatory process around the modified sutures. CONCLUSION: Application of polyhydroxybutyrate/hydroxyvalerate and heparin on the surface of surgical sutures is an effective method for prevention of abdominal adhesions.