Abstract

BACKGROUND: This study investigated the protective effects of pharmaceutical CD26/dipeptidylpeptidase-4 (CD26/DPP-4) inhibitor in lung transplantation (LTx). Changes in protein expression associated with the treatment were screened and identified to evaluate the role of kininogen-1 in early-term ischemia/reperfusion (I/R) injury after LTx.

MATERIAL AND METHODS: Orthotopic single LTx was performed in syngeneic C57BL/6 mice, with a pharmaceutical CD26/DPP-4 inhibitor (vildagliptin, subcutaneous injection, 10 mg/kg, every 12 h) administered to the investigational group. All donors were perfused and preserved with low potassium dextran (LPD). Grafts were harvested at 60 h post-transplantation after 8 h of cold ischemia. Myeloperoxidase activity and wet/dry weight ratio were measured, followed by histopathological examination. Proteins were separated, analyzed, and identified using proteomics and database searches. The target proteins were validated by Western blot. Immunohistochemical studies were performed in the same lung specimen locus.

RESULTS: Investigational group (IN) versus control group (CON) comparison showed decreased myeloperoxidase enzymatic activity, as well as decreased edema and interstitial-alveolar inflammation. Proteomics results revealed 78 spots with significant differences in abundance between the 2 groups. Fifteen proteins were identified. Kininogen-1 was up-regulated in CON and down-regulated in IN, with contrasting results for the heat shock protein 70. Immunohistochemical results revealed significantly different staining with kininogen-1 in alveolar macrophages and inflammatory cells.

CONCLUSIONS: Combined vildagliptin and LPD significantly ameliorated I/R injury after LTx. This treatment may change local pulmonary protein levels. Moreover, proper application of proteins such as kininogen-1 may enhance the protective effects against I/R injury during transplantation.

Keywords: Dipeptidyl Peptidase 4, Lung Transplantation, Proteomics, Reperfusion Injury, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization