Angiotensin II, Sympathetic nerve activity and chronic heart failure
- Authors: Wang, Yutang , Seto, Sai-Wang , Golledge, Jonathan
- Date: 2014
- Type: Text , Journal article
- Relation: Heart Failure Reviews Vol. 19, no. 2 (2014), p. 187-198
- Full Text: false
- Reviewed:
- Description: Sympathetic nerve activity has been reported to be increased in both humans and animals with chronic heart failure. One of the mechanisms believed to be responsible for this phenomenon is increased systemic and cerebral angiotensin II signaling. Plasma angiotensin II is increased in humans and animals with chronic heart failure. The increase in angiotensin II signaling enhances sympathetic nerve activity through actions on both central and peripheral sites during chronic heart failure. Angiotensin II signaling is enhanced in different brain sites such as the paraventricular nucleus, the rostral ventrolateral medulla and the area postrema. Blocking angiotensin II type 1 receptors decreases sympathetic nerve activity and cardiac sympathetic afferent reflex when therapy is administered to the paraventricular nucleus. Injection of an angiotensin receptor blocker into the area postrema activates the sympathoinhibitory baroreflex. In peripheral regions, angiotensin II elevates both norepinephrine release and synthesis and inhibits norepinephrine uptake at nerve endings, which may contribute to the increase in sympathetic nerve activity seen in chronic heart failure. Increased circulating angiotensin II during chronic heart failure may enhance the sympathoexcitatory chemoreflex and inhibit the sympathoinhibitory baroreflex. In addition, increased circulating angiotensin II can directly act on the central nervous system via the subfornical organ and the area postrema to increase sympathetic outflow. Inhibition of angiotensin II formation and its type 1 receptor has been shown to have beneficial effects in chronic heart failure patients. © 2012 Springer Science+Business Media New York.
Angiotensin converting enzyme 2 and atherosclerosis
- Authors: Wang, Yutang , Tikellis, Chris , Thomas, Merlin , Golledge, Jonathan
- Date: 2013
- Type: Text , Journal article , Review
- Relation: Atherosclerosis Vol. 226, no. 1 (2013), p. 3-8
- Full Text: false
- Reviewed:
- Description: Angiotensin converting enzyme 2 (ACE2) is a homolog of angiotensin converting enzyme (ACE) which generates angiotensin II from angiotensin I. ACE, its product angiotensin II and the downstream angiotensin type I receptor are important components of the renin-angiotensin system (RAS). Angiotensin II, the most important component of the RAS, promotes the development of atherosclerosis. The identification of ACE2 in 2000 opened a new chapter of research on the regulation of the RAS. ACE2 degrades pro-atherosclerotic angiotensin II and generates anti-atherosclerotic angiotensin 1-7. In this review, we explored the importance of ACE2 in protecting experimental animals from developing atherosclerosis and its involvement in human atherosclerosis. We also examined the published evidence assessing the importance of ACE2 in different cell types relevant to atherosclerosis and putative underlying cellular and molecular mechanisms linking ACE2 with protection from atherosclerosis. ACE2 shifts the balance from angiotensin II to angiotensin 1-7 inhibiting the progression of atherosclerosis in animal models. © 2012 Elsevier Ireland Ltd.
Resveratrol inhibits growth of experimental abdominal aortic aneurysm associated with upregulation of angiotensin-converting enzyme 2
- Authors: Moran, Corey , Biros, Erik , Krishna, Smriti , Wang, Yutang , Tikellis, Chris , Moxon, Joseph , Cooper, Mark , Norman, Paul , Burrell, Louise , Thomas, Merlin , Golledge, Jonathan
- Date: 2017
- Type: Text , Journal article
- Relation: Arteriosclerosis Thrombosis and Vascular Biology Vol. 37, no. 11 (2017), p. 2195-2203
- Full Text: false
- Reviewed:
- Description: Objective-Recent evidence suggests an important role for angiotensin-converting enzyme 2 (ACE2) in limiting abdominal aortic aneurysm (AAA). This study examined the effect of ACE2 deficiency on AAA development and the efficacy of resveratrol to upregulate ACE2 in experimental AAA. Approach and Results-Ace2 deletion in apolipoprotein-deficient mice (ApoE(-/-)Ace2(-/y)) resulted in increased aortic diameter and spontaneous aneurysm of the suprarenal aorta associated with increased expression of inflammation and proteolytic enzyme markers. In humans, serum ACE2 activity was negatively associated with AAA diagnosis. ACE2 expression was lower in infrarenal biopsies of patients with AAA than organ donors. AAA was more severe in ApoE (-/-)Ace2(-/y) mice compared with controls in 2 experimental models. Resveratrol (0.05/100-g chow) inhibited growth of pre-established AAAs in ApoE(-/-) mice fed high-fat chow and infused with angiotensin II continuously for 56 days. Reduced suprarenal aorta dilatation in mice receiving resveratrol was associated with elevated serum ACE2 and increased suprarenal aorta tissue levels of ACE2 and sirtuin 1 activity. In addition, the relative phosphorylation of Akt and ERK (extracellular signal-regulated kinase) 1/2 within suprarenal aorta tissue and gene expression for nuclear factor of kappa light polypeptide gene enhancer in B cells 1, angiotensin type-1 receptor, and metallopeptidase 2 and 9 were significantly reduced. Upregulation of ACE2 in human aortic smooth muscle cells by resveratrol in vitro was sirtuin 1-dependent. Conclusions-This study provides experimental evidence of an important role for ACE2 in limiting AAA development and growth. Resveratrol upregulated ACE2 and inhibited AAA growth in a mouse model.
A peptide antagonist of thrombospondin-1 promotes abdominal aortic aneurysm progression in the angiotensin II-infused apolipoprotein-E-deficient mouse
- Authors: Krishna, Smriti , Seto, Sai-Wang , Jose, Roby , Biros, Erik , Moran, Corey , Wang, Yutang , Clancy, Paula , Golledge, Jonathan
- Date: 2016
- Type: Text , Journal article
- Relation: Arteriosclerosis, Thrombosis, and Vascular Biology Vol. 35, no. 2 (2016), p. 389-398
- Full Text: false
- Reviewed:
- Description: OBJECTIVE - : Interaction of the activating sequence in thrombospondin-1 (TSP-1) with the conserved sequence (leucine-serine-lysine-leucine [LSKL]) in the latency-associated peptide region of latent transforming growth factor (TGF)-β complex is important in regulating TGF-β1 activity. We aimed to assess the effect of blocking peptide LSKL on the progression of pre-established abdominal aortic aneurysm in angiotensin II-infused apolipoprotein E-deficient (ApoE) mice. APPROACH AND RESULTS - : Abdominal aortic aneurysm was established in 3-month-old male ApoE mice with subcutaneous infusion of angiotensin II for 28 days. After this, mice received LSKL peptide or control SLLK (serine-leucine-leucine-lysine) peptide (4 mg/kg) via daily intraperitoneal injection for an additional 2 weeks. Administration of LSKL peptide promoted larger suprarenal aortic diameter, as determined by ultrasound and morphometric analysis, and stimulated more severe atherosclerosis within the aortic arch. In addition, mice receiving LSKL peptide exhibited elevated circulating proinflammatory cytokine levels and greater inflammatory cells within the suprarenal aorta compared with controls. Mice receiving LSKL peptide showed low plasma TGF-β1 activity and low levels of aortic tissue phosphorylated to total Smad2/3. Aortic gene expression of TGF-β receptor 1 (TGFBRI) and receptor 2 (TGFBRII), but not TGF-β1 and thrombospondin-1, were lower in mice receiving LSKL peptide than controls. LSKL peptide administration was associated with greater aortic elastin fragmentation and lower expression and activity of the TGF-β1-target gene lysyl oxidase like 1 (LOXL1). CONCLUSIONS - : Attenuation of thrombospondin-1-directed activation of TGF-β1 promotes abdominal aortic aneurysm and atherosclerosis progression in the angiotensin II-infused ApoE mouse model. © 2014 American Heart Association, Inc.