VEGF-A and VEGF-B Coordinate the Arteriogenesis to Repair the Infarcted Heart with Vagus Nerve Stimulation

Abstract

Background/Aims: Vagus nerve stimulation (VNS) suppresses arrhythmic activity and minimizes cardiomyocyte injury. However, how VNS affects angiogenesis/arteriogenesis in infarcted hearts, is poorly understood. Methods: Myocardial infarction (MI) was achieved by ligation of the left anterior descending coronary artery (LAD) in rats. 7 days after LAD, stainless-steel wires were looped around the left and right vagal nerve in the neck for vagus nerve stimulation (VNS). The vagal nerve was stimulated with regular pulses of 0.2ms duration at 20 Hz for 10 seconds every minute for 4 hours, and then ACh levels by ELISA in cardiac tissue and serum were evaluated for its release after VNS. Three and 14 days after VNS, Real-time PCR, immunostaining and western blot were respectively used to determine VEGF-A/B expressions and α-SMA- and CD31-postive vessels in VNS-hearts with pretreatment of α7-nAChR blocker mecamylamine (10 mg/kg, ip) or mACh-R blocker atropine (10 mg/kg, ip) for 1 hour. The coronary function and left ventricular performance were analyzed by Langendorff system and hemodynamic parameters in VNS-hearts with pretreatment of VEGF-A/B-knockdown or VEGFR blocker AMG706. Coronary arterial endothelial cells proliferation, migration and tube formation were evaluated for angiogenesis following the stimulation of VNS in coronary arterial smooth muscle cells (VSMCs). Results: VNS has been shown to stimulate VEGF-A and VEGF-B expressions in coronary arterial smooth muscle cells (VSMCs) and endothelial cells (ECs) with an increase of α-SMA- and CD31-postive vessel number in infarcted hearts. The VNS-induced VEGF-A/B expressions and angiogenesis were abolished by m-AChR inhibitor atropine and α7-nAChR blocker mecamylamine in vivo. Interestingly, knockdown of VEGF-A by shRNA mainly reduced VNS-mediated formation of CD31⁺ microvessels. In contrast, knockdown of VEGF-B powerfully abrogated VNS-induced formation of α-SMA⁺ vessels. Consistently, VNS-induced VEGF-A showed a greater effect on EC tube formation as compared to VNS-induced VEGF-B. Moreover, VEGF-A promoted EC proliferation and VSMC migration while VEGF-B induced VSMC proliferation and EC migration in vitro. Mechanistically, vagal neurotransmitter acetylcholine stimulated VEGF-A/B expressions through m/nACh-R/PI3K/Akt/Sp1 pathway in EC. Functionally, VNS improved the coronary function and left ventricular performance. However, blockade of VEGF receptor by antagonist AMG706 or knockdown of VEGF-A or VEGF-B by shRNA significantly diminished the beneficial effects of VNS on ventricular performance. Conclusion: VNS promoted angiogenesis/arteriogenesis to repair the infracted heart through the synergistic effects of VEGF-A and VEGF-B.

Vagus nerve stimulation optimized cardiomyocyte phenotype, sarcomere organization and energy metabolism in infarcted heart through FoxO3A-VEGF signaling

“…According to the published protocol 18 , MI model was prepared by ligating the left anterior descending coronary artery (LAD) of rats. Briefly, after anaesthetized with ketamine (50 mg/kg, i.p.)…”

“…or atropine (Atrop, 10 mg/kg, i.p.) were performed 1 h (h) before VNS (six rats/group), as described previously 18 .…”

“…Subsequent studies further demonstrated that the over-expression of cardiomyocytes' vesicular ACh transporter (VACHT) or choline acetyltransferase (ChAT) increased ACh synthesis which protected the heart against ischemia and inhibited ventricular remodeling induced by sympathetic hyperactivity or angiotensin II (Ang II) [15][16][17] . Our recent study has shown that vagus nerve stimulation (VNS) improved angiogenesis, coronary blood flow (CBF), and heart function in the infarcted heart through activating VEGF-A/B 18 , and these specific effects could be markedly abolished by Flt1 blocker AMG706, similar to inhibition of angiogenesis in adaptive cardiac hypertrophy model by a decoy VEGF receptor, Flk1-Fc. More importantly, studies have shown that VEGFs were required to maintain cardiac function, which are associated with coronary microvessels, ventricular contractile function, and energy metabolism, especially both VEGF-A for glycolysis and VEGF-B for lipid metabilism [19][20][21][22] .…”

The effects of acetylcholinesterase inhibitors on the heart in acute myocardial infarction and heart failure: From cells to patient reports

“…108 Autonomic imbalance has been shown to attenuate angiogenesis after MI, by decreasing α7nAChR. 110 In addition, AChE inhibitors have been shown to promote the expression of VEGF through the activation of α7nAChR after MI, 34 thus stimulating angiogenesis and reducing infarct size and improving cardiac function. 110 In addition, AChE inhibitors have been shown to promote the expression of VEGF through the activation of α7nAChR after MI, 34 thus stimulating angiogenesis and reducing infarct size and improving cardiac function.…”

“…109 A previous study demonstrated, VNS increased the expression of vascular endothelial growth factor (VEGF)-A and VEGF-B and activated angiogenesis in the heart after MI through a P13K/Akt/specificity protein 1 (Sp1) signalling pathway. 110 In addition, AChE inhibitors have been shown to promote the expression of VEGF through the activation of α7nAChR after MI, 34 thus stimulating angiogenesis and reducing infarct size and improving cardiac function. 33,34 It is well-known that cardiac rupture is a severe complication which can occur after MI.…”