In vivo implantation of a tissue engineered stem cell seeded hemi‐laryngeal replacement maintains airway, phonation, and swallowing in pigs

Abstract

Laryngeal functional impairment relating to swallowing, vocalisation, and respiration can be life changing and devastating for patients. A tissue engineering approach to regenerating vocal folds would represent a significant advantage over current clinical practice. Porcine hemi-larynx were de-cellularised under negative pressure. The resultant acellular scaffold was seeded with human bone marrow derived mesenchymal stem cells and primary human epithelial cells. Seeded scaffolds were implanted orthotopically into a defect created in the thyroid cartilage in 8 pigs and monitored in vivo for 2 months. In vivo assessments consisted of mucosal brushing and bronchoscopy at 1, 2, 4, and 8 weeks post implantation followed by histological evaluation post termination. The implanted graft had no adverse effect on respiratory function in 6 of the 8 pigs; none of the pigs had problems with swallowing or vocalisation. Six out of the 8 animals survived to the planned termination date; 2 animals were terminated due to mild stenosis and deep tissue abscess formation, respectively. Human epithelial cells from mucosal brushings could only be identified at Weeks 1 and 4. The explanted tissue showed complete epithelialisation of the mucosal surface and the development of rudimentary vocal folds. However, there was no evidence of cartilage remodelling at the relatively early censor point. Single stage partial laryngeal replacement is a safe surgical procedure. Replacement with a tissue engineered laryngeal graft as a single procedure is surgically feasible and results in appropriate mucosal coverage and rudimentary vocal fold development.

Limitations of recellularized biological scaffolds for human transplantation

“…In the context of acellular biological scaffolds, it is plausible that reseeding of the scaffolds with cells facilitates degradation of residual immunogenic proteins on the ECM (Q. Li et al, ) and repairs the ECM damage caused by the decellularization processes. In some instances, cells could be seeded onto the scaffold temporarily to allow for recipient cells to repopulate the scaffold, which would then decrease the risk of rejection (Herrmann et al, ). Determining the risk associated with transplantation of recellularized scaffolds for an extended period is crucial to assess the real benefit of this promising therapy.…”

In vivo feasibility study of the use of porous polyhedral oligomeric silsesquioxane implants in partial laryngeal reconstruction

“…The same species of animals was used as in previously published for our feasibility study using biologic scaffolds 13 . Briefly, eight female White/Landrace cross bred pigs, 45-50kg, were acclimatised for two weeks prior to the implantation surgery.…”

“…Again, the same approach was used as in our previously published feasibility study using biologic scaffolds 13 . In brief, human BM-MSC were obtained from consenting donors 6 undergoing therapeutic MSC and cultured for three to seven passages in supplemented αMEM (Minimal Essential Medium, Lonza, USA).…”

“…Again, the same protocols were used for seeding as previously reported for seeding of biologic-based scaffolds 13 . In brief, prepared, sterilised scaffolds were place in Bronchial Epithelial Growth Medium (BEGM BulletKit, Lonza CC-3170, USA) in customised bioreactors.…”

“…Our previous reports showed feasibility 13 , safety and potential efficacy 14 of a de-cellularised hemi-larynx seeded with human bone marrow derived mesenchymal stem cells (BM-MSC) in pigs. However, access to human donor larynxes may be a rate limiting supply chain feature of the clinical application of this approach.…”