A preclinical model for laryngeal transplantation: Anatomy and mucosal immunology of the porcine larynx

Background. A major step in translating work on laryngeal transplantation i nto clinical practice is the establishment of a preclinical model. We have investigated the anatomy and mucosal immunology of the porcine larynx in ei ght Minnesota Minipigs (12-37 weeks). Methods, Neck dissections were carried out and the vascular tree was mapped . Snap-frozen biopsies from epiglottis, supraglottis, glottis, and subglott is were prepared for conventional histology, immunohistochemistry (CD45), a nd single and two-color immunofluorescence (CD3, MHC-II, CD45). Results. The anatomy of the laryngeal skeleton was broadly similar to that of the human larynx. The blood supply is predominantly via the caudal thyro id vessels, with assistance from the cranial laryngeal artery. The porcine larynx is clearly highly immunologically active. Structured collections of leukocytes were found in the mucosal epithelium, around tubuloacinar glands , and occasionally in the submucosa. MHC-II and CD 3 cells were predominant ly found within the epithelium. The highest densities of all cell types wer e observed in the epiglottis, tailing off caudally, The lowest densities we re seen in the vocal cords. Conclusions. The porcine larynx is both anatomically and immunologically si milar to the human larynx and contains a high level of immunological organi zation. It presents an ideal preclinical model for laryngeal transplantatio n.