Expanding Horizons for Abdominal Aortic Aneurysms.
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ABSTRACT:
SUBMITTER: Rolph RC
PROVIDER: S-EPMC4714933 | biostudies-literature | 2015 Feb
REPOSITORIES: biostudies-literature
Publications
Expanding Horizons for Abdominal Aortic Aneurysms.
Rolph Rachel C RC Waltham Matthew M Smith Alberto A Kuivaniemi Helena H
Aorta (Stamford, Conn.) 20150201 1
Recent technological advances have allowed researchers to interrogate the genetic basis of abdominal aortic aneurysms in great detail. The results from these studies are expected to transform our understanding of this complex disease with both multiple genetic and environmental risk factors. Clinicians need to keep abreast of these genetic findings and understand the implications for their practice. Patients will become increasingly informed on genetic risk, and a new era of individualized risk ...[more]
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Project description:Current clinical practice for the assessment of abdominal aortic aneurysms (AAA) is based on vessel diameter and does not account for the multifactorial, heterogeneous remodeling that results in the regional weakening of the aortic wall leading to aortic growth and rupture. This study was conducted to determine correlation between a novel non-invasive surrogate measure of regional aortic weakening and the results from invasive analyses performed on corresponding ex vivo aortic samples. Tissue samples were evaluated to classify local wall weakening and likelihood of further degeneration based on non-invasive indices. A combined, image-based fluid dynamic and in-vivo strain analysis approach was used to estimate the Regional Aortic Weakness (RAW) index and assess individual aortas of AAA patients prior to elective surgery. Nine patients were treated with complete aortic resection allowing the systematic collection of tissue samples that were used to determine regional aortic mechanics, microstructure and gene expression by means of mechanical testing, microscopy and transcriptomic analyses. The RAW index was significantly higher for samples exhibiting lower mechanical strength (p = 0.035) and samples classified with low elastin content (p = 0.020). Samples with higher RAW index had the greatest number of genes differentially expressed compared to any constitutive metric. High RAW samples showed a decrease in gene expression for elastin and a down-regulation of pathways responsible for cell movement, reorganization of cytoskeleton, and angiogenesis. Please note that the sample 'characteristisc: strain' represents the in-vivo strain corresponding to each section of aorta, which is measured from dynamic CT images of patient AAA using a proprietary software.
2021-01-26 | GSE165470 | GEO
Project description:An individual's genetic background plays a significant role in his or her chances of developing an abdominal aortic aneurysm (AAA). This risk is likely to be due to a combination of multiple small effect genetic factors acting together, resulting in considerable difficulty in the identification of these factors.Methods for the identification of genetic factors associated with disease are usually based on the analysis of genetic variants in case-control studies. Over the last decade, owing to advances in bioinformatics and laboratory technology, these studies have progressed from focusing on the examination of a single genetic variant in each study to the examination of many millions of variants in a single experiment. We have conducted a series of such experiments using these methods.Our original methods using candidate gene approaches led to the initial identification of a genetic variant in the interleukin-10 gene associated with AAA. However, further studies failed to confirm this association and highlighted the necessity for adequately powered studies to be conducted, as well as the need for confirmatory studies to be performed, prior to the acceptance of a variant as a risk for disease. The subsequent application of genomic techniques to our sample set, in a global collaboration, has led to the identification of three robustly verified risk loci for AAA in the LRP1, LDLR and SORT1 genes.Genomic studies of AAA have led to the identification of new pathways involved in the pathogenesis of AAA. The exploration of these pathways has the potential to unlock new avenues for therapeutic intervention to prevent the development and progression of AAA.
| S-EPMC4474189 | biostudies-other
Project description:BACKGROUND:An abdominal aortic aneurysm (AAA) is an abnormal ballooning of the major abdominal artery. Some AAAs present as emergencies and require surgery; others remain asymptomatic. Treatment of asymptomatic AAAs depends on many factors but an important one is size of the aneurysm, as risk of rupture increases with aneurysm size. Large asymptomatic AAAs (> 5.5 cm in diameter) are usually operated on; very small AAAs (< 4.0 cm diameter) are monitored with ultrasonography. The optimal timing of surgery would benefit from further evidence. OBJECTIVES:This review compared long-term survival in patients with AAAs of diameter 4.0 to 5.5 cm who received immediate repair versus routine ultrasound surveillance. SEARCH METHODS:For this update the Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (February 2012) and CENTRAL (2012, Issue 1). Reference lists of relevant articles were checked for additional studies and the searches were supplemented by handsearches of recent conference proceedings and information from experts in the field. SELECTION CRITERIA:Randomised controlled trials in which men and women with asymptomatic AAAs of diameter 4.0 to 5.5 cm were randomly allocated to immediate repair or imaging-based surveillance at least every six months. Outcomes had to include mortality or survival. DATA COLLECTION AND ANALYSIS:Two authors (GF, MAMM) abstracted the data, which were cross-checked by the other authors (DJB, JTP). Due to the small number of trials, formal tests of heterogeneity and sensitivity analyses were not conducted. MAIN RESULTS:Four trials with a combined total of 3314 patients, the UK Small Aneurysm Trial (UKSAT), the Aneurysm Detection and Management (ADAM) trial, the Comparison of Surveillance Versus Aortic Endografting for Small Aneurysm Repair (CAESAR), and the Positive Impact of Endovascular Options for treating Aneurysms Early (PIVOTAL) fulfilled the inclusion criteria. The four trials showed an early survival benefit in the surveillance group (due to 30-day operative mortality with surgery) but no significant differences in long-term survival (adjusted hazard ratio (HR) 0.88, 95% confidence interval (CI) 0.75 to 1.02, mean follow up 10 years (UKSAT); HR 1.21, 95% CI 0.95 to 1.54, mean follow up 4.9 years (ADAM); HR 0.76, 95% CI 0.30 to 1.93, median follow up 32.4 months (CAESAR); HR 1.01, 95% CI 0.49 to 2.07, mean follow up 20 months (PIVOTAL)). The meta analyses of mortality at one year (CAESAR and PIVOTAL only) and six years (UKSAT and ADAM only) revealed a non-significant association (Peto odds ratio at one year 1.15, 95% CI 0.59 to 2.25; Peto odds ratio at six years 1.11, 95% CI 0.91 to 1.34). AUTHORS' CONCLUSIONS:The results from the four trials to date demonstrate no advantage to early repair (via open or endovascular surgery) for small AAA (4.0 to 5.5 cm) and suggest that 'best care' for these patients favours surveillance. Furthermore, the more recent trials focused on the efficacy of endovascular aneurysm repair and still failed to show benefit. Thus, both open and endovascular repair of small AAAs are not supported by currently available evidence.
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Project description:Abdominal aortic aneurysms (AAAs) are a prevalent and deadly human pathology with strong sexual dimorphism. Research demonstrates that sex hormones influence, but do not fully explain, male versus female AAA pathology. In addition to sex hormones, the X and Y sex chromosomes, and their unique complements of genes, may contribute to sexually dimorphic AAA pathology. Here, for the first time, we defined the effect of female (XX) versus male (XY) chromosome complement on AAA formation and rupture in phenotypically female mice using an established murine model. Abdominal aortas from female mice bearing the XY chromosome selectively expressed Y chromosome genes, while genes known to escape X-inactivation were higher in XX females. The majority of gene differences in XY females fell within inflammatory pathways. When XY females were infused with AngII, AAA incidences doubled and aneurysms ruptured. AAAs from XY females exhibited significant inflammation. Moreover, infusion of AngII to XY females augmented aortic activity of matrix metalloproteinases. Finally, testosterone exposure applied chronically, or as a single bolus at postnatal day 1, markedly worsened AAA outcomes in XY compared to XX females. These results demonstrate that an XY sex chromosome complement profoundly influences aortic gene expression profiles and promotes AAA severity.
2016-11-07 | GSE81580 | GEO
Project description:An aortic aneurysm is a dilatation in which the aortic diameter is ?3.0 cm. If left untreated, the aortic wall continues to weaken and becomes unable to withstand the forces of the luminal blood pressure resulting in progressive dilatation and rupture, a catastrophic event associated with a mortality of 50-80%. Smoking and positive family history are important risk factors for the development of abdominal aortic aneurysms (AAA). Several genetic risk factors have also been identified. On the histological level, visible hallmarks of AAA pathogenesis include inflammation, smooth muscle cell apoptosis, extracellular matrix degradation and oxidative stress. We expect that large genetic, genomic, epigenetic, proteomic and metabolomic studies will be undertaken by international consortia to identify additional risk factors and biomarkers, and to enhance our understanding of the pathobiology of AAA. Collaboration between different research groups will be important in overcoming the challenges to develop pharmacological treatments for AAA.
| S-EPMC4829576 | biostudies-literature
Project description:Abdominal aortic aneurysms (AAAs), which commonly occur among elderly individuals, are accompanied by a risk of rupture and subsequent high mortality. Establishment of medical therapies for the prevention of AAAs requires further understanding of the molecular pathogenesis of this condition. This report details the possible involvement of Osteoprotegerin (OPG) in the prevention of AAAs through inhibition of Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). In CaCl2-induced AAA models, both internal and external diameters were significantly increased with destruction of elastic fibers in the media in Opg knockout (KO) mice, as compared to wild-type mice. Moreover, up-regulation of TRAIL expression was observed in the media by immunohistochemical analyses. Using a culture system, both the TRAIL-induced expression of matrix metalloproteinase-9 in smooth muscle cells (SMCs) and the chemoattractive effect of TRAIL on SMCs were inhibited by OPG. These data suggest that Opg may play a preventive role in the development of AAA through its antagonistic effect on Trail.
| S-EPMC4718675 | biostudies-literature
Project description:Background Abdominal aortic aneurysm has become increasingly important owing to demographic changes. Some other diseases, for example, cholecystolithiasis, chronic obstructive pulmonary disease, and hernias, seem to co-occur with abdominal aortic aneurysm. The aim of this retrospective analysis was to identify new comorbidities associated with abdominal aortic aneurysm.Methods We compared 100 patients with abdominal aortic aneurysms and 100 control patients. Their preoperative computed tomographic scans were examined by two investigators independently, for the presence of hernias, diverticulosis, and cholecystolithiasis. Medical records were also reviewed. Statistical analysis was performed using univariate analysis and multiple logistic regression analysis.Results The aneurysm group had a higher frequency of diverticulosis (p = 0.008). There was no significant difference in the occurrence of hernia (p = 0.073) or cholecystolithiasis (p = 1.00). Aneurysm patients had a significantly higher American Society of Anesthesiology score (2.84 vs. 2.63; p = 0.015) and were more likely to have coronary artery disease (p < 0.001), congestive heart failure (p < 0.001), or chronic obstructive pulmonary disease (p < 0.001). Aneurysm patients were more likely to be former (p = 0.034) or current (p = 0.006) smokers and had a significantly higher number of pack years (p < 0.001). Aneurysm patients also had a significantly poorer lung function. In multivariate analysis, the following factors were associated with aneurysms: chronic obstructive pulmonary disease (odds ratio, OR = 12.24; p = 0.002), current smoking (OR = 4.14; p = 0.002), and coronary artery disease (OR = 2.60; p = 0.020).Conclusions Our comprehensive analysis identified several comorbidities associated with abdominal aortic aneurysms. These results could help to recognize aneurysms earlier by targeting individuals with these comorbidities for screening.
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Project description:The cardiovascular field is still searching for a treatment for abdominal aortic aneurysms (AAA). This inflammatory disease often goes undiagnosed until a late stage and associated rupture has a high mortality rate. No pharmacological treatment options are available. Three hallmark factors of AAA pathology include inflammation, extracellular matrix remodeling, and vascular smooth muscle dysfunction. Here we discuss drugs for AAA treatment that have been studied in clinical trials by examining the drug targets and data present for each drug's ability to regulate the aforementioned three hallmark pathways in AAA progression. Historically, drugs that were examined in interventional clinical trials for treatment of AAA were repurposed therapeutics. Novel treatments (biologics, small-molecule compounds etc.) have not been able to reach the clinic, stalling out in pre-clinical studies. Here we discuss the backgrounds of previous investigational drugs in hopes of better informing future development of potential therapeutics. Overall, the highlighted themes discussed here stress the importance of both centralized anti-inflammatory drug targets and rigor of translatability. Exceedingly few murine studies have examined an intervention-based drug treatment in halting further growth of an established AAA despite interventional treatment being the therapeutic approach taken to treat AAA in a clinical setting. Additionally, data suggest that a potentially successful drug target may be a central inflammatory biomarker. Specifically, one that can effectively modulate all three hallmark factors of AAA formation, not just inflammation. It is suggested that inhibiting PGE2 formation with an mPGES-1 inhibitor is a leading drug target for AAA treatment to this end.
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Project description:Recent reports of rupture in patients with abdominal aortic aneurysm (AAA) receiving B-cell depletion therapy highlight the importance of understanding the role of B cells (B1 and B2 subsets) in the development of AAA. We hypothesized that B2 cells aggravate experimental aneurysm formation. The IHC staining revealed infiltration of B cells in the aorta of wild-type (C57BL/6) mice at day 7 after elastase perfusion and persisted through day 21. Quantification of immune cell types using flow cytometry at day 14 showed significantly greater infiltration of mononuclear cells, including B cells (B2: 93% of total B cells) and T cells in elastase-perfused aortas compared with saline-perfused or normal aortas. muMT (mature B-cell deficient) mice were prone to AAA formation similar to wild-type mice in two different experimental AAA models. Contradicting our hypothesis, adoptive transfer of B2 cells suppressed AAA formation (102.0% ± 7.3% versus 75.2% ± 5.5%; P < 0.05) with concomitant increase in the splenic regulatory T cell (0.24% ± 0.03% versus 0.92% ± 0.23%; P < 0.05) and decrease in aortic infiltration of mononuclear cells. Our data suggest that B2 cells constitute the largest population of B cells in experimental AAA. Furthermore, B2 cells, in the absence of other B-cell subsets, increase splenic regulatory T-cell population and suppress AAA formation.
| S-EPMC4215033 | biostudies-literature
Project description:Gene expression profiling of abdominal aortic aneurysms (AAA) indicates that chronic inflammatory responses, active matrix metalloproteinases, and degradation of the extracellular matrix components are involved in disease development and progression. This study investigates intra- and interpersonal RNA genome-wide expression profiling differences (Illumina HumanHT-12, BeadCHIP expression) of 24 AAA biopsies from 12 patients using a single gene and pathway (GeneOntology, GO enrichment) analysis. Biopsies were collected during open surgical AAA repair and according to prior finite element analysis (FEA) from regions with the highest and lowest wall stress. Single gene analysis revealed a strong heterogeneity of RNA expression parameters within the same and different AAA biopsies. The pathway analysis of all samples showed significant enrichment of genes from three different signaling pathways (integrin signaling pathway: fold change FC 1.63, p = 0.001; cholecystokinin receptor pathway: FC 1.60, p = 0.011; inflammation mediated by chemokine signaling pathway: FC 1.45, p = 0.028). These results indicate heterogeneous gene expression patterns within the AAA vascular wall. Single biopsy investigations do not permit a comprehensive characterization of activated molecular processes in AAA disease.
| S-EPMC9225238 | biostudies-literature