In vitro endothelialization of small caliber vascular prostheses made of bacterial nanocellulose depending on coating with albumin, fibronectin or heparin

• Applicant: Dr. Max Wacker
• Subject Area: Cardiac and Vascular Surgery
• Term: from 2019 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 421965288

Coronary artery bypass grafting is the most frequent heart operation in Western society. Many patients do not have enough autologous graft material. Alternatives, such as synthetic grafts consisting of plastic fiber, did not produce acceptable results. These poor results were mainly attributed to mechanical instability and high thrombogenicity. We managed to produce innovative vascular grafts consisting of bacterial nanocellulose (BNC). These grafts have mechanical properties comparable to autologous vessels. First experiments showed a high occdlusion rate, mainly due to lack of endothelialization followed by thrombosis. Reaching endothelialization of vascular grafts by fishing for endothelial progenitor cells circulating in the blood is considered a promising method to improve patency rates. Recent studies report increased endothelialization of BNC after specific coating. In our previous work, we successfully coated BNC with albumin, fibronectin and heparin. In preliminary experiments we showed increased expansion of human microvascular endothelial cells on the coated BNC grafts. The aim of this study is to evaluate the coating’s impact on endothelialization under physiologic conditions. Therefore, we plan to use a bioreactor that is already established in our laboratory. In this bioreactor, coated and uncoated BNC-tubes will be seeded with human and ovine vascular endothelial cells or endothelial progenitor cells and will be perfused with cell culture media under physiological flow, pressure and temperature. After cultivation for three days, endothelial cell expansion on the BNC graft surface will be quantified and functionally characterized. We expect that the coatings lead to increased endothelialization, especially with endothelial progenitor cells. The results of this study will provide important information for future strategies of developing alternative graft materials and will be the basis for BNC graft assessment in in vivo animal experiments.

• DFG Programme: Research Grants