Stem cell transplantation effectively occludes bronchopleural fistula in an animal model

Background Bronchopleural fistula after lung resection still represents a challenging life-threatening complication for thoracic surgeons. Considering its extremely high mortality rate, an effective treatment is urgently required. Our project investigated the hypothesis of experimental bronchopleural fistula closure by bronchoscopic injection of autologous bone marrow-derived mesenchymal stem cells into the cavity of the fistula, evaluating its feasibility and safety in a large animal model. Methods An experimental bronchopleural fistula was created in 9 goats after right upper tracheal lobectomy. The animals were randomly assigned to two groups: one received autologous bone marrow-derived mesenchymal stem cell bronchoscopic transplantation; the other received standard bronchoscopic fibrin glue injection. Results All animals receiving bronchoscopic stem cell transplantation presented fistula closure by extraluminal fibroblast proliferation and collagenous matrix development; none (0%) died during the study period. All animals receiving standard treatment still presented bronchopleural fistula; 2 of them (40%) died. Findings were confirmed by pathology examination, computed tomography, and magnetic resonance imaging. Conclusions Bronchoscopic transplantation of bone marrow-derived mesenchymal stem cells effectively closes experimental bronchopleural fistula by extraluminal fibroblast proliferation and collagenous matrix development. Stem cells may play a crucial role in the treatment of postresectional bronchopleural fistula after standard lung resection. Although these results provide a basis for the development of clinical therapeutic strategies, the exact mechanism by which they are obtained is not yet completely clear; further studies are required to understand exactly how stem cells work in this field.