Pericardial fat pad tissue produces angiogenic factors for healing the bronchial stump

Maintaining blood flow in and supplying various anti-inflammatory or angiogenic cytokines to the bronchial stump are very important factors involved in its healing. Pericardial fat pad tissue samples surgically obtained from 20 patients were assessed, and their angiogenic ability was investigated. The messenger RNA level of all angiogenic cytokines, including vascular endothelial growth factor, fibroblast growth factor-2 (FGF-2), platelet-derived growth factor-A (PDGF-A), angiopoietin-1 (Ang-1), Ang-2 and hepatocyte growth factor (HGF) were detected in the pericardial fat pad tissue. The protein levels of all cytokines except PDGF-A increased with time from day one to day seven after primary culture of the pericardial fat pad tissue. In particular, both HGF and Ang-2 protein levels on day seven were significantly higher than those on day one (P=0.0475 and P=0.0417, respectively). On the other hand, the protein level of FGF-2 decreased in time and was significantly lower on day seven than on day one (P=0.0296). The present study demonstrated the angiogenic ability of the pericardial fat pad. These results suggest that reinforcement of the bronchial stump by the pericardial fat pad is a worthwhile and justified procedure, and may prevent bronchopleural fistula after pulmonary resections.