A novel tissue-engineered approach to problems of the postpneumonectomy space.

BACKGROUND: Transfer of viable tissue flaps and thoracoplasty are effective against pleural space complications after pneumonectomy but highly disfiguring. The aim of this study was to explore the possibility of engineered tissue to treat space complications after pneumonectomy.

METHODS: A left pneumonectomy was performed in mice, and the cavity immediately filled with the cellularized collagen matrices. First, bone marrow derived-mesenchymal stroma cells with luciferase expression were used as donor cells to evaluate cell viability and angiogenesis using bioluminescence imaging. Second, using bone marrow cells from GFP mice, histologic evaluation, immunohistochemistry for von Willebrand Factor, and flow cytometric analysis was performed compared with acellular matrix implants. The effect on bacterial clearance was examined using an empyema model with Staphylococcus aureus expressing luciferase.

RESULTS: Embedded cells proliferated within the denatured collagen matrices ex vivo. In vivo, bioluminescent imaging activity could be detected till day 8, and the slope (suggesting rate of perfusion with luciferin) increased with time up to day 6 but decreased after day 7. Although GFP-positive donor cells decreased with time, total cellularity increased. Furthermore, vessels stained by von Willebrand factor were significantly increased. Both cellularized and acellularized matrices showed bacterial clearance in vivo.

CONCLUSIONS: Cells within collagen matrices survive in the thoracic cavity at early time points. Cellularized matrices quickly lead to neovascularization and recipient cell infiltration. Both cellularized and acellularized matrices show bacterial clearance in vivo. This study indicates the potential feasibility of a novel tissue engineering approach to problems of the postpneumonectomy space.