In vitro hemo- and cytocompatibility of bacterial nanocelluose small diameter vascular grafts: Impact of fabrication and surface characteristics.

Abstract

There is an increasing need for small diameter vascular grafts with superior host hemo-and cytocompatibilities, such as low activation of platelets and leukocytes. Therefore, we aimed to investigate whether the preparation of bacterial nanocellulose grafts with different inner surfaces has an impact on in vitro host cytocompatibility. Methods We have synthesized five different grafts in a bioreactor, namely open interface surface (OIS), inverted (INV), partially air dried (PAD), surface formed in air contact (SAC) and standard (STD) that were characterized by a different surface roughness. The grafts (length 55 mm, inner diameter 5 mm) were attached to heparinized polyvinyl chloride tubes, loaded with human blood and rotated at 37˚C for 4 hours. Then, blood was analyzed for frequencies of cellular fractions, oxidative products, soluble complement and thrombin factors. The results were compared to clinically approved grafts made of polyethylene terephthalate and expanded polytetrafluoroethylene. Additionally, blood platelets were labelled with 111 Indium-oxine to visualize the distribution of adherent platelets in the loop by scintigraphy. Results SAC nanocellulose grafts with the lowest surface roughness exhibited superior performance with <10% leukocyte and <50% thrombocyte loss in contrast to other grafts that exhibited >65% leukocyte and >90% thrombocyte loss. Of note, SAC nanocellulose grafts showed lowest radioactivity with scintigraphy analyses, indicating reduced platelet adhesion.

Comparative Evaluation on Impacts of Fibronectin, Heparin–Chitosan, and Albumin Coating of Bacterial Nanocellulose Small-Diameter Vascular Grafts on Endothelialization In Vitro

“…From the clinical perspective, the preservation of endothelial function in autologous vessels is considered to be indispensable for long-term patency [ 58 , 59 ]. Bacterial nanocellulose small-diameter grafts are thought to be a promising approach in the development of acellular grafts for in vivo population with ECs [ 14 , 16 , 17 , 34 , 60 ]. However, in contrast to the native extracellular matrix, BNC scaffolds fail to provide tissue-specific proteins for cell adhesion.…”

“…The BNC grafts have shown satisfactory short-term results, which were characterized by good surgical manageability and burst pressure in the physiological environment. These grafts were also successfully surface modified to reduce the thrombogenicity, but the long-term results are still limited as reflected by low patency rates and lack of sufficient endothelialization [ 14 , 15 , 16 , 17 ].…”

Nanocellulose: Recent Advances Toward Biomedical Applications

“…[ 177 ] It was established that a smooth luminal surface was important for the bio‐ and haemocompatibility of BNC vascular grafts, as well as to reduce blood coagulation and adhesion of thrombocytes and leukocytes. [ 178 ] Synthetic BNC tubes with diminished wall thickness, smooth inner surface, and porous outer zones were proposed and verified ( Figure a) to improve graft patency by reducing thrombogenic potential and facilitating easier cell immigration along the outer layer. [ 175 ] However, dual antiplatelet treatment was necessary to maintain long‐term patency; grafts were occluded at 9 months post‐implantation otherwise.…”

Predicting the In Vivo Performance of Cardiovascular Biomaterials: Current Approaches In Vitro Evaluation of Blood-Biomaterial Interactions

“…Polymeric and metallic implant surfaces are by nature rough at a cellular level, which accounts for the observed increased thrombogenicity of these materials [ 69 ]. With respect to activation of the coagulation cascade, a recent study demonstrates that increasing surface roughness positively correlates with the number of adhered platelets [ 84 ]. Most studies in this context are focused on surface roughness and are evaluated on only a few different roughness values due to the limited manufacturing technologies.…”