Artificial Trachea and Long Term follow-up in Carinal Reconstruction in Dogs

Abstract

We have already reported successful carinal reconstruction of the trachea with an observation period of 1 - 2 years. In this study, we evaluate the long-term safety and efficacy of the reconstruction after 5-years of follow-up. The Y-shaped Marlex mesh tube was reinforced with a polypropylene spiral and coated with atelocollagen made from porcine skin. The prosthesis was 60 mm long with an outer diameter of 18 mm. Replacement of the tracheobronchial bifurcation was preformed through a right thoracotomy in a beagle dog. Bronchoscopical examination and sampling of the tracheal epithelium was performed periodically to check the function of cilia. The implanted prothesis was promptly infiltrated by the surrounding connective tissue and completely incorporated by the host trachea and bronchus. Bronchoscopically, sufficient epithelization was confirmed from the upper to the lower site of anastomosis. After 5 years neither stenosis nor dehiscence was observed. In spite of there being mesh-exposure at the luminal surface, the dog had no clinical symptoms until sacrifice for pathological examination. The bent frequency of the cilia was maintained within the normal range, indicating functional recovery of the regenerating airway. Our tracheal prosthesis is promising for clinical repair of the tracheobronchial bifurcation.

Tissue-engineered airway and “in situ tissue engineering”

“…Therefore, a polypropylene framework is used instead, 40 which can provide the regenerated airway with long-term mechanical support. 41 Experiments employing canine models have been repeated using mesh-type prostheses since the 1990s. They have demonstrated that this type of prosthesis can be applied safely for circumferential replacement of the cervical trachea, 42 thoracic trachea, 43 carinal bifurcation, 44,45 or left main bronchus.…”

Experimental regeneration of canine larynx: a trial with tissue engineering techniques

“…Regenerative medicine has recently been accepted as a useful clinical discipline that ensures and Our group has achieved useful outcomes in regeneration of the trachea [14,15], esophagus [16], stomach [17], and cricoid area [18] with this in situ tissue engineering technique.…”

“…Using tracheal prosthesis with porous-type collagen and polypropylene as a scaffold, Nakamura et al [14] and Okumura et al [15] have previously achieved favorable outcomes in canine tracheal regeneration; i.e. favorable cellular invasions of intact collagen, proper epithelialization on the luminal side of implants; and complete integration of the scaffold with the recipient's tissue were established.…”

Overview of Tracheal Tissue Engineering: Clinical Need Drives the Laboratory Approach

“…Collagen-coated polypropylene mesh reinforced with a polypropylene mesh cylinder is a trachea prosthetic that has been extensively studied. 53,54,57,[60][61][62][63][64]73,77,80,81,88,104 There have also been many alterations to the basic collagen/polypropylene scaffold, by adding a cell-loaded collagen gel to the outer surface of the construct, 57,80 coating vitrigel on the epithelium, 81 and coating poly (L-lactic acid-co-e-caprolactone) on the lumen. 73 Coating scaffolds with peptides, like the RGD cell adhesion ligand, is another approach used to enhance cell attachment.…”

“…In a long-term follow-up study, one dog survived for 5 years with this construct. 54 In addition, a biomimetic approach in scaffold design and geometry has been considered by some groups. For example, Moroni et al 52 explored how macroscopic topology (i.e., discrete cartilage arches) affected cellular metabolism and ECM production, and established that an anatomically designed scaffold (created from a CT image) created an environment for a high degree of chondrocyte differentiation in vitro as compared to cylindrical and toroidal tubular scaffolds.…”