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BackgroundThe trachea, a vital conduit in the lower airway system, can be affected by various disorders, such as tracheal neoplasms and tracheoesophageal fistulas, that often necessitate reconstruction. While short-segment defects can sometimes be addressed with end-to-end anastomosis, larger defects require tracheal reconstruction, a complex procedure with no universally successful replacement strategy. Tissue engineering offers a promising solution for tracheal repair, particularly focusing on regenerating its epithelium, which plays a critical role in protecting the respiratory system and facilitating mucociliary clearance. However, replicating the complex structure and functionality of the tracheal epithelium remains a significant challenge, with key hurdles including proper cell differentiation, functional mucociliary clearance, and addressing the relative lack of vascular supply to the trachea.SummaryCurrent tissue engineering approaches, including biomaterial scaffolds, decellularized tissues, and scaffold-free methods, have shown varying levels of success, while in vitro air-liquid interface (ALI) cultures have provided valuable insights into epithelial modeling. Despite these advances, translating these findings into effective in vivo applications remains difficult due to challenges such as immune responses, inadequate integration with host tissue, and limited longterm functionality of engineered constructs. Overcoming these barriers requires further refinement of cell sources, scaffold materials and bioactive factors that promote vascularization and sustained epithelial function.Key MessagesThis review evaluates the current strategies and modeling, biomaterial scaffolds, cells, and bioactive factors used in tracheal epithelium regeneration, as well as the methods employed to assess their success through histological, functional, and molecular analyses. While significant progress has been made, the development of a safe, functional, and clinically viable trachealgraft remains elusive, underscoring the need for continued innovation in airway tissue engineering. Future advancements in biomaterial design, stem cell technology, and bioreactor-based tissue maturation hold promise for addressing challenges.
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Imaging-guided bioreactor for de-epithelialization and long-term cultivation of ex vivo rat trachea
Recent synergistic advances in organ-on-chip and tissue engineering technologies offer opportunities to create in vitro -grown tissue or organ constructs that can faithfully recapitulate their in vivo counterparts. Such in vitro tissue or organ constructs can be utilized in multiple applications, including rapid drug screening, high-fidelity disease modeling, and precision medicine. Here, we report an imaging-guided bioreactor that allows in situ monitoring of the lumen of ex vivo airway tissues during controlled in vitro tissue manipulation and cultivation of isolated rat trachea. Using this platform, we demonstrated partial removal of the rat tracheal epithelium ( i.e. , de-epithelialization) without disrupting the underlying subepithelial cells and extracellular matrix. Through different tissue evaluation assays, such as immunofluorescent staining, DNA/protein quantification, and electron beam microscopy, we showed that the epithelium of the tracheal lumen can be effectively removed with negligible disruption in the underlying tissue layers, such as cartilage and blood vessel. Notably, using a custom-built micro-optical imaging device integrated with the bioreactor, the trachea lumen was visualized at the cellular level, and removal of the endogenous epithelium and distribution of locally delivered exogenous cells were demonstrated in situ . Moreover, the de-epithelialized trachea supported on the bioreactor allowed attachment and growth of exogenous cells seeded topically on its denuded tissue surface. Collectively, the results suggest that our imaging-enabled rat trachea bioreactor and localized cell replacement method can facilitate creation of bioengineered in vitro airway tissue that can be used in different biomedical applications.
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- Award ID(s):
- 2143620
- PAR ID:
- 10382014
- Date Published:
- Journal Name:
- Lab on a Chip
- Volume:
- 22
- Issue:
- 5
- ISSN:
- 1473-0197
- Page Range / eLocation ID:
- 1018 to 1031
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D1LC01105G
