Tracheal cartilage - evaluating the potential of a novel biomaterial for reconstructive cardiovascular procedures

Modern cardiovascular medicine aims for procedures that preferably involve biological materials and, ideally, living implants. Thereby, the regenerative capacity of the target organ may be preserved or even supported, with a potential implant growth capacity during the following time. In the current study we sought to evaluate the integrative capacity of vital and non-vital tracheal cartilage rings (TCRs) of allogenic or xenogenic origin (allo-/xeno-vTCR; allo-/xeno-nvTCR) as biomaterials under the in vivo functional load of the circulatory system. Ovine and porcine vTCRs and nvTCRs were implanted in the mitral valve (MV) position for 3 and 9 months (n = 3 each), respectively, in lambs. MV function and TCR position were analysed by echocardiography. Tissue morphology (planimetry), vitality (live/dead-assay) and implant endothelialization (scanning electron microscopy) were analysed. No functional impairment or significant MV insufficiency or stenosis was observed in any group. TCR shrinkage was observed in all xeno-TCRs and allo-nvTCRs at 3 months. Only TCRs of allogenic groups at 9 months and allo-vTCRs at 3 months showed a ring area comparable to its size at implantation. Moreover, allogenic vital cartilage showed superior tissue integration, greater endothelialization, less inflammation and calcification. Interestingly, in this group viable cartilage cells were found up to 9 months after implantation. Allogenic viable cartilage may represent a well-suited living material for reconstructive cardiovascular procedures, and further studies are warranted to elucidate the benefits of this novel material, particularly as a structurally supportive component in growing recipients.