Scaffold-Free Tubular Tissues Created by a Bio-3D Printer Undergo Remodeling and Endothelialization when Implanted in Rat Aortae.

Manabu Itoh,Kazuyoshi Uchihashi,Ryo Noguchi,Shigeki Morita,Koichi Node,Jun-Ichi Oyama,Koichi Nakayama,Shuji Toda,Kojirou Furukawa,Keiji Kamohara,Donghui Zhu

doi:10.1371/journal.pone.0136681

Abstract

BackgroundSmall caliber vascular prostheses are not clinically available because synthetic vascular prostheses lack endothelial cells which modulate platelet activation, leukocyte adhesion, thrombosis, and the regulation of vasomotor tone by the production of vasoactive substances. We developed a novel method to create scaffold-free tubular tissue from multicellular spheroids (MCS) using a “Bio-3D printer”-based system. This system enables the creation of pre-designed three-dimensional structures using a computer controlled robotics system. With this system, we created a tubular structure and studied its biological features.Methods and ResultsUsing a “Bio-3D printer,” we made scaffold-free tubular tissues (inner diameter of 1.5 mm) from a total of 500 MCSs (2.5× 104 cells per one MCS) composed of human umbilical vein endothelial cells (40%), human aortic smooth muscle cells (10%), and normal human dermal fibroblasts (50%). The tubular tissues were cultured in a perfusion system and implanted into the abdominal aortas of F344 nude rats. We assessed the flow by ultrasonography and performed histological examinations on the second (n = 5) and fifth (n = 5) day after implantation. All grafts were patent and remodeling of the tubular tissues (enlargement of the lumen area and thinning of the wall) was observed. A layer of endothelial cells was confirmed five days after implantation.ConclusionsThe scaffold-free tubular tissues made of MCS using a Bio-3D printer underwent remodeling and endothelialization. Further studies are warranted to elucidate the underlying mechanism of endothelialization and its function, as well as the long-term results.

Highlights

Synthetic vascular prostheses lack antithrombotic properties, biocompatibility and infection resistance
The scaffold-free tubular tissues made of multicellular spheroids (MCS) using a Bio-3D printer underwent remodeling and endothelialization
Human umbilical vein endothelial cells (HUVEC), human aortic smooth muscle cells (HASMC) and human normal dermal fibroblasts (HNDFB) were cultured in an appropriate medium, i.e., endothelial cell medium (ECM), smooth muscle cell medium (SMCM), fibroblast medium (FM), respectively, with growth supplement (Lonza)

Summary

Introduction

Synthetic vascular prostheses lack antithrombotic properties, biocompatibility and infection resistance. When the cells were cultured in non-adhesive wells, they tended to aggregate with each other and form a spheroidal structure within 24 hours The advantage of this approach is that multicellular components can be mixed into one spheroid, thereby promoting the formation of extracellular matrices, such as collagen or elastin. Small caliber vascular prostheses are not clinically available because synthetic vascular prostheses lack endothelial cells which modulate platelet activation, leukocyte adhesion, thrombosis, and the regulation of vasomotor tone by the production of vasoactive substances. We developed a novel method to create scaffold-free tubular tissue from multicellular spheroids (MCS) using a “Bio-3D printer”-based system. This system enables the creation of pre-designed three-dimensional structures using a computer controlled robotics system. We created a tubular structure and studied its biological features

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Conclusion