Preliminary Study on the Development of In Vitro Human Respiratory Epithelium Using Collagen Type I Scaffold as a Potential Model for Future Tracheal Tissue Engineering

Mh Busra Fauzi,Zahra Rashidbenam,Yogeswaran Lokanathan,Ruszymah Binti Hj Idrus,Mohd Heikal Mohd Yunus,Rohaina Che Man,Aminuddin Bin Saim

doi:10.3390/app11041787

Abstract

Pathological conditions of the tracheal epithelium, such as postoperative injuries and chronic conditions, often compromise the functionality of the respiratory epithelium. Although replacement of the respiratory epithelium using various types of tracheal transplantation has been attempted, there is no predictable and dependable replacement method that holds for safe and practicable long-term use. Therefore, we used a tissue engineering approach for ex vivo regeneration of the respiratory epithelium (RE) construct. Collagen type I was isolated from sheep tendon and it was fabricated in a three-dimensional (3D) scaffold format. Isolated human respiratory epithelial cells (RECs) and fibroblasts from nasal turbinate were co-cultured on the 3D scaffold for 48 h, and epithelium maturation was allowed for another 14 days in an air–liquid interface culture system. The scanning electron microscope results revealed a fabricated porous-structure 3D collagen scaffold. The scaffold was found to be biocompatible with RECs and fibroblasts and allows cells attachment, proliferation, and migration. Immunohistochemical analysis showed that the seeded RECs and fibroblasts were positive for expression of cytokeratin 14 and collagen type I markers, respectively, indicating that the scaffold supports the native phenotype of seeded cells over a period of 14 days. Although a longer maturation period is needed for ciliogenesis to occur in RECs, the findings suggest that the tissue-engineered RE construct is a potential candidate for direct use in tracheal epithelium replacement or tracheal tube reengineering.

Highlights

The tracheal epithelial layer is a well-known barrier that prevents underlying tissues from external irritants such as allergens, airborne particulates, infectious agents, and noxious gases, and their potential penetration
We found that the respiratory epithelial cells (RECs) and fibroblast co-existed in the same area and the RECs had not yet migrated to form a separate layer (Figure 4)
Our findings showed the formation of a confluent layer of co-cultured RECs and fibroblasts on the surface of the porous freeze-dried collagen type I scaffold, which indicated the presence of favorable porosity and pore size for RECs and fibroblasts to form a multilayer structure

Summary

Introduction

The tracheal epithelial layer is a well-known barrier that prevents underlying tissues from external irritants such as allergens, airborne particulates, infectious agents, and noxious gases, and their potential penetration. The consequence of the injuries introduced into the epithelium can even cause the loss of surface epithelium integrity and partial or complete shedding of the epithelium [5]. These conditions necessitate epithelium repair or replacement. Ex-vivo-engineered respiratory epithelium has been integral to understanding the pathologies and underlying mechanisms of many respiratory-related diseases. It can potentially be used for studying drug interactions with the reparatory epithelium and developing regenerative therapies for respiratory epithelium diseases [7]

Methods

Results

Discussion

Conclusion