Sitagliptin is an inhibitor of the enzyme dipeptidylpeptidase-4 (DPP-4) and represents an established drug in type 2 diabetes mellitus treatment. However, Sitagliptin may also have several antiinflammatory properties. For example, it is known that DPP-4-inhibition prevents procalcitonin from being cleaved to a truncated form that lacks 2 amino acids. As the investigators described recently, truncated procalcitonin targets the CRLR-RAMP1-receptor on vascular endothelium and induces VE-cadherin-phosphorylation which leads to leakage of fluids and proteins from vessels. Furthermore, many other immunoregulatory targets such as substance p, CXCL10 or NF-kB have been reported to be modified by DPP-4. Therefore, it can be assumed that Sitagliptin possibly represents a powerful drug in inflammatory circumstances.~The aim of this study is to prove possible antiinflammatory properties by conducting an observational trial in cardiac surgery patients. All patients undergo cardiac surgery with the use of cardiopulmonary bypass (CBP) which is known to trigger a systemic inflammatory response syndrome (SIRS). Group 1 suffers from diabetes mellitus type two and regularly takes Sitagliptin which is continued perioperatively. Group 2 also suffers from diabetes mellitus type 2 but does not take Sitagliptin. Group 3 has no diabetes mellitus but also undergoes cardiac surgery. To determine the effect of Sitagliptin under inflammatory conditions deep immune phenotyping and a cytokine assay is performed from blood withdrawals 24h after surgery. Moreover, the sublingual microcirculation is measured two times after the operation.~Taking all measurements of the cellular immune system, the humoral immune system and the vasculature into account it should be possible to define the immunoregulatory effects of Sitagliptin treatment more properly.
Sitagliptin is an inhibitor of the enzyme dipeptidylpeptidase-4 (DPP-4) and represents an established drug in type 2 diabetes mellitus treatment. However, Sitagliptin may also have several antiinflammatory properties. Within this study the investigators examine the effects of perioperative Sitagliptin intake on the inflammatory response after cardiopulmonary bypass.