scholarly journals Adipocyte in vascular wall can induce the rupture of abdominal aortic aneurysm

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Hirona Kugo ◽  
Nobuhiro Zaima ◽  
Hiroki Tanaka ◽  
Youhei Mouri ◽  
Kenichi Yanagimoto ◽  
...  
Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Dawn A Savio ◽  
Anita R Halpern ◽  
Yuchuan Wu ◽  
Wei Li ◽  
Joseph Sypek ◽  
...  

Abdominal aortic aneurysm (AAA) is an inflammatory disorder characterized by local connective tissue degradation, macrophage recruitment and infiltration leading to aortic dilation and rupture. Aneurysms of the abdominal aorta represent a significant cardiovascular risk for which inflammation plays an integral role in the defined pathology. Genetic ablation of metalloprotease-12 (MMP-12) eliminates metalloelastase activity and attenuates aneurysm formation in apoE−/− mice. In the current study, a selective MMP-12 inhibitor, WAY-644 was evaluated in the well-established murine model of ANGII-induced aneurysm formation. This inhibitor displays activity for murine MMP-12, IC50 = 6.3 nM by FRET analysis, with low crossreactivity for other MMPs (exception MMP-8), and has established in vivo efficacy in inflammation models. Coadministration of WAY-644 to hyperlipidemic apoE−/− mice during ANGII infusion (1.44 mg/kg) for 28d alters the severity of AngII-induced AAAs as measured by changes in abdominal aortic wet weights and typical AAA classification. As expected, plasma MMP-12 protease activity measured by FRET analysis was inhibited. RNA profiling of abdominal aortic aneurysm tissue characterizes ANGII-induced AAA expansion driven by macrophage infiltration, destructive MMP production and attenuation by MMP-12 inhibition. The transcription of a subset of proinflammatory genes activated with ANGII treatment was repressed by the inhibitor. These genes include quantitative markers of macrophage accumulation in the vessel wall, CD68, MCP1/CCL2, CCR2, MMP-12, and Csf1. Associated reductions in gene markers for inflammation and oxidative stress, ie., heme oxidase (HO), nitric oxide synthase (nos2), Ikbkb, and Stat3 also correlate with MMP-12 antagonism. These changes occur in the absence of lipid changes (TC or TG), or quantitative changes in aortic arch lesions in the ANGII-infused animals. The findings support a mechanism whereby MMP-12 metalloelastase inactivation reduces macrophage recruitment to aneurysmal lesion sites, to lessen activated-macrophage expression of proinflammatory cytokines that figure prominently in vascular wall destruction and the pathogenesis of AAAs.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Chie Miyamoto ◽  
Hirona Kugo ◽  
Keisuke Hashimoto ◽  
Tatsuya Moriyama ◽  
Nobuhiro Zaima

AbstractAbdominal aortic aneurysm (AAA) is a vascular disease characterized by weakening of the vascular walls. Male sex is a risk factor for AAA, and peak AAA incidence occurs in men 10 years earlier than in women. However, the growth rate of AAA is faster in women, and women have a higher mortality due to AAA rupture. The mechanisms underlying sex-related differences in AAA remain unknown. Herein, we evaluated the effects of ovariectomy (OVX) on AAA in rats. Upon evaluation of the effects of OVX and AAA induction, AAA incidence rate and the aneurysm diameter increased in the OVX group. However, the histopathology in the developed AAA wall was not different between groups. When the effects of OVX on the vascular wall without AAA induction were evaluated, elastin and collagen levels were significantly decreased. Furthermore, the level of matrix metalloproteinase-9 significantly increased in the OVX group. According to our results, it is speculated that decreased levels of collagen and elastin fibers induced by OVX might be involved in increased incidence rate and diameter of AAA. Weakening of the vascular wall before the onset of AAA might be one reason for the faster rate of AAA growth in women.


2019 ◽  
Vol 133 (13) ◽  
pp. 1421-1438 ◽  
Author(s):  
Miquel Navas-Madroñal ◽  
Cristina Rodriguez ◽  
Modar Kassan ◽  
Joan Fité ◽  
José R. Escudero ◽  
...  

Abstract Abdominal aortic aneurysm (AAA) is a degenerative vascular disease with a complex aetiology that remains to be fully elucidated. Clinical management of AAA is limited to surgical repair, while an effective pharmacotherapy is still awaited. Endoplasmic reticulum (ER) stress and mitochondrial dysfunction have been involved in the pathogenesis of cardiovascular diseases (CVDs), although their contribution to AAA development is uncertain. Therefore, we aimed to determine their implication in AAA and investigated the profile of oxysterols in plasma, specifically 7-ketocholesterol (7-KC), as an ER stress inducer. In the present study, we determined aortic ER stress activation in a large cohort of AAA patients compared with healthy donors. Higher gene expression of activating transcription factor (ATF) 6 (ATF6), IRE-1, X-binding protein 1 (XBP-1), C/EBP-homologous protein (CHOP), CRELD2 and suppressor/enhancer of Lin-12-like (SEL1L) and greater protein levels of active ATF6, active XBP1 and of the pro-apoptotic protein CHOP were detected in human aneurysmatic samples. This was accompanied by an exacerbated apoptosis, higher reactive oxygen species (ROS) production and by a reduction in mitochondrial biogenesis in the vascular wall of AAA. The quantification of oxysterols, performed by liquid chromatography-(atmospheric pressure chemical ionization (APCI))-mass spectrometry, showed that levels of 7-KC were significantly higher while those of 7α-hydroxycholesterol (HC), 24-HC and 27-HC were lower in AAA patients compared with healthy donors. Interestingly, the levels of 7-KC correlate with the expression of ER stress markers. Our results evidence an induction of ER stress in the vascular wall of AAA patients associated with an increase in circulating 7-KC levels and a reduction in mitochondrial biogenesis suggesting their implication in the pathophysiology of this disease.


2017 ◽  
Vol 66 (5) ◽  
pp. 499-506 ◽  
Author(s):  
Hirona Kugo ◽  
Nobuhiro Zaima ◽  
Hiroki Tanaka ◽  
Keisuke Hashimoto ◽  
Chie Miyamoto ◽  
...  

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Chanwoo Kim ◽  
Sandeep Kumar ◽  
Dong Ju Son ◽  
In-Hwan Jang ◽  
Hanjoong Jo

Abdominal aortic aneurysm (AAA) is characterized by weakening of the vessel wall, followed by progressive expansion of the diseased aortic segment. MicroRNAs (miRNAs) have emerged as key regulator of gene expression in the cardiovascular diseases and may play a key role in therapeutically targeting AAA development. Although,vascular wall degradation by matrix metalloproteases (MMPs) is the key mechanism in AAA development, their targeting through miRNAs have never been studied. We identified microRNA-712 (miR-712) as a novel Angiotensin II(AngII)-sensitive miRNA which is upregulated in the abdominal aortic endothelium of AngII-infused mice. Mechanistically, we identified that miR-712 directly regulates two key endogenous inhibitors of MMP: tissue inhibitor of metalloproteinase 3 (TIMP3) and reversion inducing cysteine-rich protein with kazal motifs (RECK). Furthermore, inhibition of miR-712 by subcutaneous injection of anti-miR-712 significantly decreased MMP activity in the AngII-infused abdominal aorta wall, prevented the dilatation of aortae and significantly reduced AAA incidence from 80% (8/10) to 20% (2/10), compared to its mismatched control in ApoE -/- mice. Interestingly, based on the seeding sequence, we identified miR-205 as the human homolog of miR-712. miR-205 was also upregulated by AngII treatment and like miR-712 regulated MMPs activity via TIMP3 and RECK. Moreover, inhibition of miR-205 dramatically inhibits AngII-induced AAA development. We also found that miR-205 was significantly upregulated in the aortic sections of AAA patients in comparison to the healthy controls. Our findings demonstrate that AngII-sensitive miRNAs, miR-712 and miR-205, regulate MMP activity through TIMP3 and RECK and play important role in the pathogenesis of AAA. These results suggest that targeting these miRNAs using their inhibitors may hold promise as a therapeutic strategy to prevent the development of AAA.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jingyuan Sun ◽  
Hongping Deng ◽  
Zhen Zhou ◽  
Xiaoxing Xiong ◽  
Ling Gao

Abdominal aortic aneurysm (AAA) was previously ascribed to weaken defective medial arterial/adventitial layers, for example, smooth muscle/fibroblast cells. Therefore, besides surgical repair, medications targeting the medial layer to strengthen the aortic wall are the most feasible treatment strategy for AAA. However, so far, it is unclear whether such drugs have any beneficial effect on AAA prognosis, rate of aneurysm growth, rupture, or survival. Notably, clinical studies have shown that AAA is highly associated with endothelial dysfunction in the aged population. Additionally, animal models of endothelial dysfunction and endothelial nitric oxide synthase (eNOS) uncoupling had a very high rate of AAA formation, indicating there is crucial involvement of the endothelium and a possible pharmacological solution targeting the endothelium in AAA treatment. Endothelial cells have been found to trigger vascular wall remodeling by releasing proteases, or recruiting macrophages along with other neutrophils, into the medial layer. Moreover, inflammation and oxidative stress of the arterial wall were induced by endothelial dysfunction. Interestingly, there is a paradoxical differential correlation between diabetes and aneurysm formation in retinal capillaries and the aorta. Deciphering the significance of such a difference may explain current unsuccessful AAA medications and offer a solution to this treatment challenge. It is now believed that AAA and atherosclerosis are two separate but related diseases, based on their different clinical patterns which have further complicated the puzzle. Therefore, a thorough investigation of the interaction between endothelium and medial/adventitial layer may provide us a better understanding and new perspective on AAA formation, especially after taking into account the importance of endothelium in the development of AAA. Moreover, a novel medication strategy replacing the currently used, but suboptimal treatments for AAA, could be informed with this analysis.


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