Vascular Remodeling Process of Heparin-Conjugated Poly(ε-Caprolactone) Scaffold in a Rat Abdominal Aorta Replacement Model

Abstract

In the field of vascular graft research, poly-ε-caprolactone (PCL) is used owing to its good mechanical strength and biocompatibility. In this study, PCL scaffold was prepared by electrospinning and surface modification with heparin via hexamethylenediamine. Then the scaffolds were implanted into the infrarenal abdominal aorta of Wistar rats and contrast-enhanced micro-ultrasound was used to monitor the patency of grafts after implantation. These grafts were extracted from the rats at 1, 3, and 6 months for histological analysis, immunofluorescence staining, and scanning electron microscopy observation. Although some grafts experienced aneurysmal change, results showed that all implanted grafts were patent during the course of 6 months and these grafts demonstrated well-organized neotissue with endothelium formation, smooth muscle regeneration, and extracellular matrix formation. Such findings confirm feasibility to create heparin-conjugated scaffolds of next-generation vascular grafts.

Hydrogel Complex Electrospun Scaffolds and Their Multiple Functions in In Situ Vascular Tissue Engineering

“…PCLH scaffold preparation was performed according to our previously published literature. ,, In short, PCL was dissolved in a DCM/methanol (volume ratio: 5:1) solution at a concentration of 0.2 g/mL. The electrospinning parameters were set as follows: a voltage of 15 kV, receive distance of 17 cm, and injection rate of 3 mL/h to obtain a tubular PCL scaffold.…”

“…The structure and function of regenerated blood vessel were similar to those of the native aorta after three months, showing the promising potential of in situ VTE. We also prepared small-diameter heparin-modified PCL (PCLH) scaffolds by electrospinning and directly implanting them into animal models including rats, rabbits, and canines according to the concept of in situ VTE. − The PCLH scaffold can maintain long-term in vivo patency . However, a high aneurysm incidence was observed in all animal models (4/10 in rats, 1/1 in canines, and 4/6 in rabbits), which negatively impacts the success of VTE grafts.…”

Preparation of Small‐Diameter Tissue‐Engineered Vascular Grafts Electrospun from Heparin End‐Capped PCL and Evaluation in a Rabbit Carotid Artery Replacement Model

“…Briefly, the inner and outer layers were cut into 0.5 × 0.5 cm rectangular shape and placed into pre‐warmed test tube at 37 °C, citrated standard plasma (50 µL) and kaolinum (50 µL) pipetted, and finally incubated for 3 min. On adding the calcium chloride solution (50 µL), the timer started to measure the clotting time …”

“…This is because only when the newly generated endothelium at the inner layer is integral, the implanted vascular scaffolds can effectively prevent platelet attaching and coagulation occurring . At the same time, the extracellular matrix (ECM) secretion and smooth muscle cell (SMC) maturation are also imperative to provide mechanical supporting force following the scaffold degradation to ensure vascular integrity …”

Systematic Review of Tissue-Engineered Vascular Grafts

“…Each article analyzed in this review created its own TEVG, although there were certain materials that were commonly used, such as biodegradable polymers, or biological materials. Notably, some researchers used heparin in the design of TEVGs ( Jiang et al, 2016 ; Koobatian et al, 2016 ; Hu et al, 2017 ; Ju et al, 2017 ; Madhavan et al, 2018 ; Xu et al, 2018 ; Jin et al, 2019a ; Jin et al, 2019b ; Ran et al, 2019 ; Shi et al, 2019 ; Smith et al, 2019 ; Wang et al, 2019 ). The addition of heparin to materials prevents thrombosis and enhances biocompatibility ( Aslani et al, 2020 ).…”