Bone morphogenetic protein-2 stimulation of cartilage regeneration in canine tracheal graft

Graft stenosis is among the most serious post-surgical complications that can occur after tracheal transplantation. Typically, stenosis is caused by resorption of tracheal cartilage. Bone morphogenetic protein-2 (BMP-2) is efficient at stimulating bone or cartilage regeneration. In this study, BMP-2 is tested for its effects on stimulation of cartilage regeneration in tracheal transplantation.

For tracheal autotransplantation, 24 mongrel dogs were divided equally into four groups and BMP-2 was injected between the cartilage rings at doses of 1, 3, 5 or 7 mg. For tracheal allotransplantation, 12 mongrel dogs were divided equally into two groups. One group received 5 mg of BMP-2 per graft, and the other received collagen only as a control. The grafts were harvested after 4 weeks and subjected to pathologic analysis. The diameter of the graft lumen and areas of new cartilage regeneration were measured.

Regenerated cartilage areas were found in both the injected area and around the perichondrium. The areas of regenerated cartilage, as well as the diameter of the tracheal lumen, increased significantly with increasing concentrations of BMP-2. Five milligrams per milliliter was the most effective dose of BMP-2 in this study.

BMP-2 can significantly stimulate cartilage regeneration in tracheal grafts and also can be used to prevent stenosis after tracheal transplantation.