Study objectives: Fibroblast growth factor (FGF)-2 is one of the most powerful angiogenic growth factors to be evaluated as an agent for the promotion of angiogenesis. The aim of this study is to investigate whether intratracheal administration of controlled-release FGF-2 microspheres restores pulmonary function in beagle dogs with emphysema.
Design: Randomized, controlled, experimental animal study.
Subjects: Eighteen Wister rats and 15 adult beagle dogs.
Methods: In the rat study, we compared the time profiles of the radioactivity remaining after intratracheal injection of 125I-labeled FGF-2, either incorporated with the controlled-release microspheres or as an aqueous solution. In the dog study, elastase-induced emphysema models were developed in 10 animals, classified into the following three groups: control group (n = 5), emphysema model with empty microspheres-treated group (FGF - group, n = 5), and emphysema model with FGF-2 containing microspheres-treated group (FGF + group, n = 5).
Results: In the rat study, controlled-release microspheres maintained higher whole-lung FGF-2 concentrations after intratracheal administration. In the dog study, Pa(O2) in the FGF + group was significantly higher than in the FGF - group after treatment. Pulmonary perfusion dynamic MRI revealed significant improvement in the signal intensity of damaged lung with the FGF + group. Linear intercept of the FGF + group was significantly reduced than the FGF - group.
Conclusion: Results indicate that intratracheal administration of FGF-2 induced an increase in pulmonary blood flow in the damaged lung and led to recovery of pulmonary function. The controlled-release microsphere system increased the effectiveness of FGF-2.