Effect of chronic pretreatment of angiotensin-converting receptor blocker on no-reflow phenomenon in patients with acute myocardial infarction undergoing percutaneous coronary intervention.

AIMS: Angiotensin receptor blockers (ARBs) exert favorable effects on the vascular system, which are not directly related to hypertension lowering function. The no-reflow phenomenon determines the prognosis in patients after acute myocardial infarction (AMI). Early ARB treatment has many beneficial effects on the prognosis after AMI. In this study, we tested the hypothesis that ARB treatment before admission would have beneficial effects on the development of the no-reflow phenomenon after infarction. METHODS: We investigated 276 consecutive patients with AMI undergoing successful primary percutaneous coronary intervention (PCI). No-reflow was defined as thrombolysis in myocardial infarction (TIMI) flow grade <3, which was determined by the TIMI frame count method using angiographic images obtained just after PCI and stenting. RESULTS: Compared with patients without ARB treatment, patients with ARB had more frequently hypertension and ST resolution (P < 0.05), but no significant difference was found in the other clinical characteristics (age, sex, Hyperlipidaemia, Diabetes mellitus, etc) between the two groups. A total of 51 patients receiving chronic ARB treatment before admission have lower incidence of the no-reflow phenomenon than those without chronic ARB treatment (8.7% and 26.7%, P= 0.003). However, the incidence of the no-reflow phenomenon between the patients with and without hypertension had no significant difference. Multivariable logistic regression analysis revealed that ARB pretreatment was a significant predictor of the no-reflow phenomenon, whereas blood pressure was found to be insignificant. CONCLUSION: Chronic pretreatment of ARB is associated with the reduction of the no-reflow phenomenon in patients with reperfused AMI and could preserve microvascular integrity after AMI independent of blood pressure lowering, which may contribute to better functional recovery.

Cyclic stretch upregulates SDF-1alpha/CXCR4 axis in human saphenous vein smooth muscle cells.

Cyclic stretch (CS) mediates different cellular functions in vascular smooth muscle cells and involves in neointimal hyperplasia and subsequent atherosclerosis of vein grafts. Here, we investigated whether CS can modulate stromal cell-derived factor-1alpha (SDF-1alpha)/CXCR4 axis in human saphenous vein smooth muscle cells. We found CS induced the upregulation of SDF-1alpha and CXCR4 in human saphenous vein smooth muscle cells in vitro, which was dependent on PI3K/Akt/mTOR pathway. Furthermore, CS augmented human saphenous vein smooth muscle migration and focal adhesion kinase (FAK) activation by PI3K/Akt/mTOR pathway. Interestingly, the upregulation of SDF-1alpha/CXCR4 axis was instrumental in CS-induced saphenous vein smooth muscle cell migration and FAK activation, as showed by AMD3100, an inhibitor of SDF-1alpha/CXCR4 axis, partially but significantly blocked the CS-induced cellular effects. Thus, those data suggested SDF-1alpha/CXCR4 axis involves in CS-mediated cellular functions in human saphenous vein smooth muscle cells.