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The purpose of this work was to test whether brain-penetrating angiotensin-converting enzyme (ACE) inhibitors (e.g., perindopril), as opposed to nonbrain-penetrating ACE inhibitors (e.g., enalapril and imidapril), may reduce the cognitive decline and brain injury in Alzheimer's disease (AD). We first compared the effect of perindopril, enalapril, and imidapril on cognitive impairment and brain injury in a mouse model of AD induced by intracerebroventricular (i.c.v.) injection of amyloid-β (Aβ)1-40. Perindopril, with significant inhibition of hippocampal ACE, significantly prevented cognitive impairment in this AD mouse model. This beneficial effect was attributed to the suppression of microglia/ astrocyte activation and the attenuation of oxidative stress caused by iNOS induction and extracellular superoxide dismutase down-regulation. In contrast, neither enalapril nor imidapril prevented cognitive impairment and brain injury in this AD mouse. We next examined the protective effects of perindopril on cognitive impairment in PS2APP-transgenic mice overexpressing Aβ in the brain. Perindopril, without affecting brain Aβ deposition, significantly suppressed the increase in hippocampal ACE activity and improved cognition in PS2APP-transgenic mice, being associated with the suppression of hippocampal astrocyte activation and attenuation of superoxide. Our data demonstrated that the brain-penetrating ACE inhibitor perindopril, as compared to non-brain-penetrating ACE inhibitors, protected against cognitive impairment and brain injury in experimental AD models. [ABSTRACT FROM AUTHOR]

This study was undertaken to elucidate a novel mechanism underlying angiotensin II-induced cardiac injury, focusing on the role of oxidative stress and myocardial capillary density. Salt-loaded Dahl salt-sensitive hypertensive rats (DS rats), a useful model for hypertensive cardiac remodeling or heart failure, were orally given irbesartan (an AT1 receptor blocker), tempol (a superoxide dismutase mimetic) or hydralazine (a vasodilator). Irbesartan significantly ameliorated left ventricular ischemia and prevented the development of cardiac hypertrophy and fibrosis in DS rats. The benefits were associated with the attenuation of oxidative stress, normalization of myocardial capillary density and inhibition of capillary endothelial apoptosis. Moreover, DS rats with significant cardiac hypertrophy and fibrosis displayed decreased myocardial vascular endothelial growth factor (VEGF) expression and increased cardiac apoptosis signal-regulating kinase 1 (ASK1) activation. Treatment with irbesartan significantly reversed these phenotypes. Tempol treatment of DS rats mimicked all the above-mentioned effects of irbesartan, indicating the critical role of oxidative stress in cardiac injury. We also investigated the role of VEGF and ASK1 in oxidative stress-induced endothelial apoptosis by using cultured endothelial cells from wild-type and ASK1-deficient mice. Oxidative stress-induced ASK1 activation led to endothelial apoptosis, and VEGF treatment prevented oxidative stress-induced endothelial apoptosis by inhibiting ASK1 activation. We obtained the first evidence that oxidative stress-induced cardiac VEGF repression and ASK1 activation caused the enhancement of endothelial apoptosis and contributed to a decrease in myocardial capillary density. These effects resulted in angiotensin II-induced progression of cardiac injury.

Background: Monocyte chemoattractant protein-1 (MCP-1) plays an important role in the pathogenesis of acute coronary syndrome. We have recently demonstrated that the administration of edaravone before reperfusion attenuated reperfusion injury in patients with acute myocardial infarction (AMI)., Methods: Plasma MCP-1 levels were measured in 45 consecutive patients with AMI (edaravone group, n=25; control group, n=20). In the edaravone group, 30 mg edaravone was intravenously infused just before reperfusion. Plasma samples were obtained before and at 24h, 3, 5, 7, and 14 days after reperfusion. Cardiovascular events were defined as cardiac death, subacute thrombosis, or fatal arrhythmia. Heart failure requiring rehospitalization was evaluated at 12 months after reperfusion., Results: Plasma MCP-1 levels were not different between the two groups before reperfusion. Compared with the placebo group, the edaravone group had statistically lower maximum creatine kinase-MB levels (218±31 IU/l versus 145±21 IU/l, p<0.05) and plasma MCP-1 levels on day 3 after reperfusion (873±118 pg/ml versus 516±66 pg/ml, p<0.05). Heart failure requiring rehospitalization occurred in four patients in the control group, but did not occur in the edaravone group (p<0.05). At 12 months after reperfusion, left ventricular ejection fraction was statistically higher in the edaravone group than in the control group (62±2% versus 54±3%, p<0.05)., Conclusion: Edaravone suppressed plasma MCP-1, improved left ventricular ejection fraction, and reduced rehospitalization due to heart failure. Suppression of plasma MCP-1 level by edaravone might induce better prognosis for AMI patients.