Time to retract Lancet paper on tissue engineered trachea transplants

Incompletely Decellularized Tracheal Matrix Scaffold for Tissue Engineering

BACKGROUND

Dense cartilaginous extracellular matrix makes decellularization and repopulation of tracheal cartilage difficult. However, the dense matrix isolates cartilaginous antigens from the recipient's immune system. Therefore, allorejection may be avoided by removing antigens from noncartilaginous tissues. In this study, incompletely decellularized tracheal matrix scaffolds were developed for tracheal tissue engineering.

METHODS

Brown Norway rat tracheae were decellularized with 4% sodium deoxycholate treatment. The cell and antigen removal efficacy, histoarchitecture, surface ultrastructure, glycosaminoglycan, collagen contents, mechanical properties, and chondrocyte viability of the scaffold were evaluated in vitro. Brown Norway rat tracheal matrix scaffolds ( n = 6) were implanted subcutaneously into Lewis rats and observed for 4 weeks. Brown Norway rat tracheae ( n = 6) and Lewis rat scaffolds ( n = 6) were implanted as controls. Histologic analysis of macrophage and lymphocyte infiltration was performed.

RESULTS

One decellularization cycle removed all cells and antigens from noncartilaginous tissue. Incomplete decellularization preserved the structural integrity of the tracheal matrix and chondrocyte viability. Except for 31% glycosaminoglycan loss, the scaffold had comparable collagen content and tensile and compressive mechanical properties to those of the native trachea. The allogeneic scaffold showed remarkably reduced CD68 + , CD8 + , and CD4 + cell infiltration compared with the allografts and demonstrated similar cell infiltration to the syngeneic scaffold. It also maintained the three-dimensional tracheal structure and cartilage viability in vivo.

CONCLUSIONS

Incompletely decellularized trachea did not induce immunorejection and maintained the integrity and viability of cartilage in vivo. Tracheal decellularization and repopulation can be simplified for urgent tracheal replacement.

CLINICAL RELEVANCE STATEMENT

The present study describes the development of an incomplete decellularization protocol that creates a decellularized matrix scaffold for tracheal tissue engineering, aiming to provide preliminary data that this method may generate suitable tracheal scaffolds for use in tracheal replacement.

Application of tissue engineering techniques in tracheal repair: a bibliometric study

Transplantation of tissue-engineered trachea is an effective treatment for long-segment tracheal injury. This technology avoids problems associated with a lack of donor resources and immune rejection, generating an artificial trachea with good biocompatibility. To our knowledge, a systematic summary of basic and clinical research on tissue-engineered trachea in the last 20 years has not been conducted. Here, we analyzed the development trends of tissue-engineered trachea research by bibliometric means and outlined the future perspectives in this field. The Web of Science portal was selected as the data source. CiteSpace, VOSviewer, and the Bibliometric Online Analysis Platform were used to analyze the number of publications, journals, countries, institutions, authors, and keywords from 475 screened studies. Between 2000 and 2023, the number of published studies on tissue-engineered trachea has been increasing. Biomaterials published the largest number of papers. The United States and China have made the largest contributions to this field. University College London published the highest number of studies, and the most productive researcher was an Italian scholar, Paolo Macchiarini. However, close collaborations between various researchers and institutions from different countries were generally lacking. Despite this, keyword analysis showed that manufacturing methods for tracheal stents, hydrogel materials, and 3D bioprinting technology are current popular research topics. Our bibliometric study will help scientists in this field gain an in-depth understanding of the current research progress and development trends to guide their future work, and researchers in related fields will benefit from the introduction to transplantation methods of tissue-engineered trachea.

Preclinical and clinical orthotopic transplantation of decellularized/engineered tracheal scaffolds: A systematic literature review

Severe tracheal injuries that cannot be managed by mobilization and end-to-end anastomosis represent an unmet clinical need and an urgent challenge to face in surgical practice; within this scenario, decellularized scaffolds (eventually bioengineered) are currently a tempting option among tissue engineered substitutes. The success of a decellularized trachea is expression of a balanced approach in cells removal while preserving the extracellular matrix (ECM) architecture/mechanical properties. Revising the literature, many Authors report about different methods for acellular tracheal ECMs development; however, only few of them verified the devices effectiveness by an orthotopic implant in animal models of disease. To support translational medicine in this field, here we provide a systematic review on studies recurring to decellularized/bioengineered tracheas implantation. After describing the specific methodological aspects, orthotopic implant results are verified. Furtherly, the only three clinical cases of compassionate use of tissue engineered tracheas are reported with a focus on outcomes.