The Effects of Nebivolol in an Ex Vivo Model of Diabetes Established in Human Saphenous Vein Grafts

Project no. 21833 · Status: Kapanmış (Yayın bekleniyor) · 2020

Summary

Objective: Long-term hyperglycemia in diabetic patients triggers the development of cardiovascular comorbidities by inducing oxidative stress, inflammation, and vascular dysfunction, and accelerates the development of restenosis in the newly placed graft after coronary artery bypass grafting (CABG) surgery, leading to an increased risk of morbidity and mortality. In our study, it was aimed to investigate the effects of nebivolol, a third-generation beta blocker, on oxidative stress, inflammatory MMPs (MMP-2, MMP-9, MMP-14), and endogenous MMP inhibitors (Tissue Inhibitor of Metalloproteinase-2; TIMP-2), guidance molecules that mediate inflammation (netrin-1, ephrin-A2, sema-3A, slit-2), integrins (CD41/CD61), vascular proliferation and dysfunction in an ex vivo standard diabetic human saphenous vein graft model.Material and Methods: Human saphenous vein (HSV) segments (n=10) taken from patients who underwent CABG operation were divided into 5 groups as 3 mm rings after the surrounding tissues were cleaned and the endothelial layers were gently removed. The rings were then incubated for 24 hours in a medium containing 30 mM glucose and/or 10 µM nebivolol or 0.1 % DMSO . Reactive oxygen species (ROS) levels in HSV graft were determined by lucigenin/luminol chemiluminescence method; MMP-2 and MMP-9 expression/activities by gelatin zymography; Expressions of MMP-14, TIMP-2, α-smooth muscle actin (α-SMA), netrin-1, ephrin-A2, sema-3A, slit-2, and CD41/CD61 were examined by immunostaining/scoring method. In addition, the contractile responses of HSV grafts to potassium chloride (KCl), noradrenaline (NA), and serotonin (5-HT) and relaxation responses to acetylcholine (ACh) and papaverine were evaluated in the isolated organ bath system.Results: High glucose-induced oxidative stress by increasing ROS levels. In addition, glucose up-regulates MMP-2 expression/activity, MMP-14, α-SMA, netrin-1, ephrin-A2 and CD41/CD61 expressions, while it is down-regulating TIMP-2, sema-3A and slit-2 expressions. In contrast, nebivolol inhibited oxidative stress, inflammation mediated by MMPs, CD41/CD61, and guidance molecules, and vascular smooth muscle cell (VSMC) proliferation. High glucose damage in HSV rings significantly reduced the contractile responses to KCl, NA, and 5-HT. Nebivolol, on the other hand, ameliorated the decreased responses to all contractile agents and induced vasodilation compared to control. However, relaxation responses to papaverine were not affected by glucose and/or nebivolol. Furthermore, glucose and/or nebivolol did not alter the susceptibility of HSV rings to contractile agents.Conclusion: Nebivolol may contribute to the prevention of restenosis and early graft failure and to preserve the functional performance of the graft by inhibiting oxidative damage, inflammation, and proliferation, and preventing vasospasm in diabetic patients undergoing HSV grafting.

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