Nondestructive Monitoring of Degradable Scaffold-Based Tissue-Engineered Blood Vessel Development Using Optical Coherence Tomography

Summary

A step by step protocol for nondestructive and long-period monitoring the process of vascular remodeling and scaffold degradation in real-time culture of biodegradable polymeric scaffold-based tissue-engineered blood vessels with pulsatile stimulation using optical coherence tomography is described here.

Abstract

Engineered vascular grafts with structural and mechanical properties similar to natural blood vessels are expected to meet the growing demand for arterial bypass. Characterization of the growth dynamics and remodeling process of degradable polymer scaffold-based tissue-engineered blood vessels (TEBVs) with pulsatile stimulation is crucial for vascular tissue engineering. Optical imaging techniques stand out as powerful tools for monitoring vascularization of engineered tissue enabling high-resolution imaging in real-time culture. This paper demonstrates a nondestructive and fast real-time imaging strategy to monitor the growth and remodeling of TEBVs in long-term culture by using optical coherence tomography (OCT). Geometric morphology is evaluated, including vascular remodeling process, wall thickness, and comparison of TEBV thickness in different culture time points and presence of pulsatile stimulation. Finally, OCT provides practical possibilities for real-time observation of the degradation of polymer in the reconstructing tissues under pulsatile stimulation or not and in each vessel segment, by compared with the assessment of polymer degradation using scanning electron microscopic(SEM) and polarized microscope.

Introduction

Tissue-engineered blood vessels (TEBVs) is of the most promising material as an ideal vascular graft¹. In order to develop grafts to be clinically useful with similar structural and functional properties as native vessels, multiple techniques have been designed to maintain vascular function^2,3. Although there have been engineered vessels with acceptable patency rates during implantation and in Phase III clinical study⁴, long-term culture and high cost also show the necessity of monitoring the development of TEBVs. Understanding of extracellular matrix(ECM) growth....

Protocol

1. Degradable PGA Scaffold based Tissue-engineered Vessels Culture

1. PGA Scaffold Fabrication
   1. Sew PGA mesh (19 mm diameter and 1 mm thick) around silicone tubing sterilized by ethylene oxide (17 cm length, 5.0 mm diameter, and 0.3 mm thick) using 5-0 suture.
   2. Sew polytetrafluoroethylene (ePTFE, 1cm length) with 4-0 suture onto each end of PGA mesh and overlapped by 2 mm.
   3. Dip PGA scaffolds with the hand in 1 mol/L NaOH for 1 min to adjust the spatial structure of the mesh and soa.......

Discussion

To generate engineered vessels with structural and mechanical properties similar to those of native blood vessels can lead to shorten the time for clinical use and is the ultimate goal of vascular engineering. Optical imaging techniques permit the visualization of tissue engineered vascular specific components, which cannot monitor individual constructs throughout culture and exposure grafts to a culture environment without compromising sterility⁷. In this article, the culture chamber is separated.......

Materials

Name	Company	Catalog Number	Comments
PGA mesh	Synthecon
silicone tube	Cole Parmer
connector	Cole Parmer
intravascular OCT system	St. Jude Medical, Inc	ILUMIEN™ OPTIS™ SYSTEM
scanning electron microscopic	Philips	FEI Philips XL-30
polarized microscope	Olympus	Olympus BX51
sutures	Johnson & Johnson
pulsatile pump	Guangdong Cardiovascular Institute
LightLab Imaging software	St. Jude Medical, Inc