Vascular graft storage solution preserves endothelial function

Abstract

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Karl Landsteiner Institute Cardiovascular Research Background Saline is still the most widely used storage and flushing solution in cardiovascular procedures despite knowing evidence of its influence on the human endothelial cell function. Aim of this study was to assess the effect of DuraGraft©, an intraoperative graft treatment solution, on human saphenous vein segments, rat aortic segments and human umbilical vein endothelial cells (HUVECs) in comparison to saline. Methods Within 12 patients undergoing aortocoronary bypass surgery, saphenous vein graft segments were randomized to DuraGraft© (n=12/6) or saline (n=12/6) solution before intraoperative storage. These segments as well as rat aortic segments underwent assessment of vascular function in a multichamber isometric myograph system in comparison to Krebs-Henseleit solution (KHS), a physiologic organ buffer solution. Additionally, human umbilical vein endothelial cells (HUVECs) were used for cell viability tests. Results KCl-induced contraction showed a tendency toward increase when treated with DuraGraft© compared to normal saline preservation of human vein segments (24.73±16.22 vs. 15.59±9.53 N/m2, P Conclusion DuraGraft© demonstrated a favorable effect on graft relaxation and contraction indicating preservation of vascular endothelial function. Saline is clearly not only inferior to this specialized solution but may show additional harmful effects to viability.

The Past, Present, and Future of Tubular Melt Electrowritten Constructs to Mimic Small Diameter Blood Vessels – A Stable Process?

“…[ 30,37,85 ] The rhombus geometry can also be applied to different tissues, for example, kidney tubules, to achieve a similar potent effect of orientation. [ 101 ] The potency of geometrical features on cell behavior and maturation was also reported with other fabrication methods and is highly effective, especially on muscle lineage cells. [ 102 ] To obtain the required toolpaths for MEW, specific G‐Code coding is required in most cases.…”

“…Efforts have been made to overcome this obstacle by introducing thin catching fibers into the constructs [ 50 ] or generate codes that produce tightly woven structures with reduced pore sizes in tubular geometries. [ 101,119 ] On the other hand, several promising approaches in biofabrication use methods like SES and hydrogel networks to create biocompatible structures, but they might not meet the required mechanical characteristics required for a long‐term patent tube. Combining MEW with these already existing constructs would allow utilizing the benefits of both structures while minimizing their drawbacks.…”

“…To increase the probability for attachment of cells during the first culturing steps, a denser fiber mesh and thus a larger surface is beneficial and increases the efficiency of cell seeding. [101,117] In terms of vascular applications, denser meshes potentially also help the ECs to develop an intact monolayer on the lumen. Van Genderen et al showed the feasibility of rhombus-shaped geometries with fiber distances of 200 μm to be suitable for proximal tubule cells but not for umbilical cord ECs.…”

“…Van Genderen et al showed the feasibility of rhombus-shaped geometries with fiber distances of 200 μm to be suitable for proximal tubule cells but not for umbilical cord ECs. [101] Since monolayer formation and spanning pores is related to cell size, it becomes clear that future tubular MEW geometries require smaller pore sizes of ≈100 μm and less. [118] While already possible to achieve these geometries, to attain highly regular geometries in this pore size, [119] further optimizations to minimize fiber jumping are necessary.…”