Plasma Dipeptidyl-peptidase-4 Activities With No-reflow and Bleeding

ST-segment elevation myocardial infarction (STEMI) is an acute manifestation of coronary heart disease, remaining a frequent cause of death.A better understanding of risk factors and pathogenic mechanisms underlying STEMI may help improve the prognosis and life quality of these patients.Dipeptidyl peptidase 4 (DPP4) is an exopeptidase expressed on the surface of diverse cells, cleaving off amino-terminal dipeptides with either L-proline, L-alanine or serine at the penultimate position. As a cell surface protein, it participates in immune regulation, signal transduction and apoptosis. DPP4 also circulates as a soluble form in the plasma. Soluble DPP4 came from either membrane type clearance or secreted by cells like endothelial cells, with enzymatic activity. Plasma DPP4 activity (DPP4a) are elevated in several diseases, including type 2 diabetes, obesity, atherosclerosis and osteoporosis. Basic studies have showed that DPP4 inhibition leads improved survival and heart function after cardiac ischemia-reperfusion (I/R) injury, and this is partly due to activation of AKT (pAKT), pGSK3 and ANP pathways. Also inhibition of DPP4 can alleviate atherosclerosis and heart failure. Accordingly, one could hypothesize that high DPP4a may worsen myocardial I/R injury, causing poorer cardiovascular outcomes. However, no study has evaluated whether DPP4a is associated with adverse clinical outcomes in STEMI patients.