Antisense Oligodeoxynucleotide Inhibition of Vascular Angiotensin-Converting Enzyme Expression Attenuates Neointimal Formation

Abstract

Abstract-It has been proposed that vascular angiotensin-converting enzyme (ACE) plays an important role in regulating vascular growth. Indeed, ACE inhibitors have been reported to prevent neointimal formation after vascular injury in a rat carotid artery model. However, classic pharmacological experiments cannot exclude the potential contributions of hemodynamics and the circulating renin-angiotensin system (RAS). In this study, we used antisense oligodeoxynucleotide (ODN) to obtain local blockade of vascular ACE expression without effects on systemic hemodynamics and circulating RAS. To increase the effectiveness of antisense action, we modified the hemagglutinating virus of Japan-liposome ODN delivery method by cotransfection with nuclear protein (high mobility group 1 [HMG-1]) and RNase H. In vitro experiments showed the enhanced efficacy of antisense ODN by cotransfection of HMG-1 and RNase H compared with ODN alone. In vivo transfection of antisense ACE ODNs into intact uninjured rat carotid artery resulted in a significant reduction of vascular ACE activity, and cotransfection of HMG-1 and RNase H showed further reduction. We examined the effects of local blockade of vascular ACE expression on neointimal formation after vascular injury. Transfection of antisense ACE ODNs resulted in the attenuation of neointimal formation, whereas sense and scrambled ODNs did not. Blood pressure, heart rate, and serum ACE activity were not affected by antisense treatment. Key Words: gene therapy Ⅲ restenosis Ⅲ renin-angiotensin system Ⅲ antisense oligonucleotides Ⅲ hemagglutinating virus of Japan O ne of the current controversies in cardiovascular research is the existence of a functional tissue angiotensin system 1-4 in the blood vessel. The presence of a vascular angiotensin system has been reported previously. [5][6][7] Furthermore, we have described that vascular angiotensin-converting enzyme (ACE) expression is induced in the intimal smooth muscle cells of rat carotid artery and abdominal aorta in response to vascular injury. 8,9 This injury model has provided us with the opportunity to examine the functional role of local angiotensin production. Using a dose range of an ACE inhibitor, we demonstrated that the magnitude of neointimal lesion reduction correlated closely with the degree of vascular ACE inhibition. 10 We have interpreted these data as supportive evidence for a functional role of tissue angiotensin. However, the blockade of tissue angiotensin required an extremely high dosage of ACE inhibitors, which was invariably accompanied by the suppression of circulating renin angiotensin and the reduction of systemic blood pressure. Therefore, it is still unclear whether the local blockade of vascular angiotensin can indeed prevent neointimal formation without producing a systemic blockade of circulating renin angiotensin and/or without affecting hemodynamics. Furthermore, ACE inhibition also results in bradykinin accumulation and nitric oxide induction, which may contribute to the inhibition of neointimal hyperpla...

From Skeleton to Cytoskeleton

“…36 Consistently, the RAS is activated in vascular neointima in response to injury, manifested by the increased ACE activity and the upregulated expression of AT 1 R. 37 This may explain why ACE inhibitors can prevent injury-induced neointima formation and restenosis. 38 Experimental results support the findings of clinical trials by showing that RAS blockade inhibits vascular remodeling after injury. 39,40 Although Ang II is known to promote myofibroblast migration, 41 our study using the conditioned medium from differentiated osteoblasts further points to that osteocalcin acts as a natural stimulant to release Ang II in the adventitial fibroblasts and Ang II subsequently functions as an autacoid to trigger fibroblast differentiation to myofibroblasts via the induction of ␣-SMA expression and upregulation of fibronectin.…”

Angiotensin-Converting Enzyme and Vascular Remodeling

“…A follow-up study by the same group, using an antisense oligonucleotide against ACE in a rat vascular injury model, showed a significant decrease in neointima formation. 26 The mechanisms by which ACE and Ang II can induce neointimal thickening or restenosis are only partly elucidated. The AT 1 receptor has been shown to play a central role.…”

Angiotensin-Converting Enzyme (ACE) Dimerization Is the Initial Step in the ACE Inhibitor-Induced ACE Signaling Cascade in Endothelial Cells

“…Selective overexpression of ACE in the heart also results in morphological changes in the atria, arrhythmia, and sudden death (Xiao et al, 2004). Antisense oligonucleotides against ACE, in contrast, are reported to prevent neointimal formation after balloon angioplasty (Morishita et al, 2000), and ACE inhibitors decrease vascular hypertrophy in hypertensive animals (Clozel et al, 1991). Furthermore, ACE inhibitors, such as ramiprilat, exert beneficial effects on endothelial function and vascular remodeling (Schartl et al, 1994;Mancini et al, 1996) and protect against the progression of atherosclerosis and the occurrence of cardiovascular events in humans (Heart Outcomes Prevention Evaluation Study Investigators, 2000).…”