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

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.

A Comprehensive Review on Collagen Type I Development of Biomaterials for Tissue Engineering: From Biosynthesis to Bioscaffold

“…Notably, natural-based materials are not only more sustainable, but they also have higher biocompatibility, improved biodegradability, and in general, little to no toxicity [ 233 ]. Furthermore, in the context of the circular economy and sustainability, collagen sources such as bovine hide off-cuts [ 75 ], pig skin [ 82 ], chicken skin and eggshells [ 66 , 68 ], sheep legs [ 234 ], and fish scales [ 235 ] can be obtained from food waste. Moving forward, there is a significant need for protocols considering green chemistry such as using and fabricating products that are biodegradable and non-toxic to the environment.…”

Evaluating Feasibility of Human Tissue Engineered Respiratory Epithelium Construct as a Potential Model for Tracheal Mucosal Reconstruction

“…Selection of nasal turbinate over trachea was due to the following reasons: (a) nasal turbinate is harvested via non-invasive methods as compared to tracheae, which is often collected via invasive methods (i.e., tracheotomy), and this causes further stenosis and structural damage to tracheae in the tissue donor [38], (b) nasal turbinate is more readily available as compared to tracheae and (c) since nasal turbinate can be available from an autologous source, as opposed to allogeneic RECs (in which the cell donor and recipient patient are different individuals), it does not elicit an immune reaction in the tissue recipient. The RECs were following an established protocol [10] by which the expression of CK14 and 18, MUC5AC and Ki67 [35] and immunocytochemical expression of markers acetyl β-tubulin, CK14, MUC5AC and Ki67 were proven [35,36]. It has been shown that knocking down CK14 results in reduced cell proliferation and delay in cell cycle progression [39].…”

“…The isolation and culture of respiratory epithelial and fibroblast cells was performed as previously described [10] with slight modification. Nasal turbinate specimens discarded during turbinectomy were collected under aseptic conditions from six patients.…”

“…Diseases that involve tracheal tissues include congenital tracheal anomalies [1], tracheal neoplasm [2], infection [3], inflammation [4], trauma, and post-intubation injuries [5]. Treatments utilizing foreign materials such as titanium mesh [6,7], naturally derived materials such as cellulose [8], nonviable allograft [9], tissue engineering [10] and various types of tracheal transplantation have been tried. Application of such grafts often results in unfavorable outcomes such as chronic inflammation [7], immunogenicity [11] and non-degradability [12] in the human body.…”

Application of Conditioned Medium for In Vitro Modeling and Repair of Respiratory Tissue

“…As the airways are continually exposed to foreign agents and infections, airborne toxicants can potentially translocate through an intact or compromised epithelial barrier, generating possible systemic effects [12,14,15]. The epithelial damage can even result in the loss of surface epithelial integrity and partial or total epithelium shedding [16,17]. Consequently, developing and validating in vitro models to assess the biological responses to disruptions of this first-line upper airway defense is critical [18][19][20].…”