Effect of heparin-binding growth factor-1 on bronchial healing in canine lung allograft transplantation

Failure of airway healing complicates lung transplantation. Local application of heparin-binding growth factor-1 induces neovascularization in vivo. To determine the effect of direct application of heparin-binding growth factor-1 on bronchial healing, we performed single left lung allotransplantations in 12 dogs, and wrapped the bronchial anastomosis with Gelfoam impregnated with either recombinant heparin-binding growth factor-1 (100 micrograms, n = 6) or saline solution (n = 6) in a blinded fashion. After 21 days, the bronchial anastomosis was studied by gross examination, light and electron microscopy, bromodeoxyuridine uptake, measurement of bronchial breaking strength, and high-speed computerized tomography to assess bronchial cross-sectional area and distensibility. The transplanted lung was examined histologically for concomitant lung rejection. No significant difference was found between the two groups in histologic bronchial healing scores, proliferation index, bronchial breaking strength, cross-sectional area, anastomotic distensibility, or local blood flow as estimated by high-speed computerized tomography scan. In the growth factor group, both increased neovascularization and lung rejection were found at histologic evaluation. We conclude that, although the use of heparin-binding growth factor-1 increased perianastomotic neovascularization, it did not contribute to improved bronchial healing, possibly because of increased lung rejection.