An Exploratory Study into the Implantation of Arytenoid Cartilage Scaffold in the Horse.

The research article details the study on using a tissue engineering approach to treat arytenoid chondritis (a pathological condition causing deformity and dysfunction of the cartilage) in horses. Key findings note the successful use of decellularized equine arytenoid cartilage as a graft preseeded with bone marrow-derived nucleated cells (BMNCs), resulting in appropriate incorporation within native tissue without hindering the horse’s respiratory function.

Understanding the Problem

• Horses can suffer from severe respiratory dysfunction due to a condition called arytenoid chondritis or arytenoid chondropathy, which leads to deformity and dysfunction of the arytenoid cartilage.
• The current treatment involves removing the affected cartilage, which although can help improve the air blockage, also poses the horse to complications such as tracheal penetration of oropharyngeal content and collapse of the unsupported soft tissue next to the cartilage.

Tissue Engineering Approach

• The researchers investigated a tissue engineering method to reconstruct the arytenoid cartilage in an attempt to offer a superior treatment for arytenoid chondritis.
• They used decellularized equine arytenoid cartilages, turning them into an acellular scaffold. This process involves removing all the cells from the cartilage, leaving only the structural scaffold, which can then be seeded with new cells.
• The scaffold was then implanted in a full-thickness defect created in the arytenoids of eight horses.

Experiment Design

• The experiment was conducted bilaterally, with one side of each horse receiving an implant preseeded with autologous bone marrow-derived nucleated cells (BMNCs).
• The researchers performed monitoring of the arytenoids’ structure and function for up to four months, using laryngeal ultrasound, endoscopy at rest and during high-speed treadmill exercise, followed by histological evaluation after euthanasia.

Findings

• They found that the implantation did not impact the horses’ laryngeal respiratory function or swallowing capability, although a temporary granuloma (an inflammatory growth) did form on the medial aspect of the arytenoids.
• Ultrasonic observation showed a postoperative increase in both the thickness and cross-sectional area of the arytenoid body, though this regression was faster in the arytenoids that did not receive BMNCs.
• Upon examination after the animals were euthanized, the tissue showed signs of epithelialization of the mucosal surface and successful integration of the implanted scaffold into native arytenoid tissue with a minimal adverse cellular reaction.
• By two months after implantation, remodeling of the scaffold material was evident. Preseeding the scaffold with BMNCs was seen to speed up the degradation and incorporation rate of the scaffold.

Conclusion

• The conclusion of the study suggests the surgical feasibility and functionality of replacing a part of the arytenoid cartilage with a tissue-engineered graft incorporating BMNCs, preventing arytenoid collapse during exercise.