Biomarkers For Abdominal Aortic Aneurysm Research Articles

Current Prognostic Biomarkers for Abdominal Aortic Aneurysm: A Comprehensive Scoping Review of the Literature.

Abdominal aortic aneurysm (AAA) is a progressive dilatation of the aorta that can lead to aortic rupture. The pathophysiology of the disease is not well characterized but is known to be caused by the general breakdown of the extracellular matrix within the aortic wall. In this comprehensive literature review, all current research on proteins that have been investigated for their potential prognostic capabilities in patients with AAA was included. A total of 45 proteins were found to be potential prognostic biomarkers for AAA, predicting incidence of AAA, AAA rupture, AAA growth, endoleak, and post-surgical mortality. The 45 proteins fell into the following seven general categories based on their primary function: (1) cardiovascular health, (2) hemostasis, (3) transport proteins, (4) inflammation and immunity, (5) kidney function, (6) cellular structure, (7) and hormones and growth factors. This is the most up-to-date literature review on current prognostic markers for AAA and their functions. This review outlines the wide pathophysiological processes that are implicated in AAA disease progression.

Identification of biomarkers for abdominal aortic aneurysm in Behçet's disease via mendelian randomization and integrated bioinformatics analyses.

Behçet's disease (BD) is a complex autoimmune disorder impacting several organ systems. Although the involvement of abdominal aortic aneurysm (AAA) in BD is rare, it can be associated with severe consequences. In the present study, we identified diagnostic biomarkers in patients with BD having AAA. Mendelian randomization (MR) analysis was initially used to explore the potential causal association between BD and AAA. The Limma package, WGCNA, PPI and machine learning algorithms were employed to identify potential diagnostic genes. A receiver operating characteristic curve (ROC) for the nomogram was constructed to ascertain the diagnostic value of AAA in patients with BD. Finally, immune cell infiltration analyses and single-sample gene set enrichment analysis (ssGSEA) were conducted. The MR analysis indicated a suggestive association between BD and the risk of AAA (odds ratio [OR]: 1.0384, 95% confidence interval [CI]: 1.0081-1.0696, p = 0.0126). Three hub genes (CD247, CD2 and CCR7) were identified using the integrated bioinformatics analyses, which were subsequently utilised to construct a nomogram (area under the curve [AUC]: 0.982, 95% CI: 0.944-1.000). Finally, the immune cell infiltration assay revealed that dysregulation immune cells were positively correlated with the three hub genes. Our MR analyses revealed a higher susceptibility of patients with BD to AAA. We used a systematic approach to identify three potential hub genes (CD247, CD2 and CCR7) and developed a nomogram to assist in the diagnosis of AAA among patients with BD. In addition, immune cell infiltration analysis indicated the dysregulation in immune cell proportions.

Identification and Evaluation of Blood-Based Biomarkers for Abdominal Aortic Aneurysm.

Blood-based biomarkers for abdominal aortic aneurysm (AAA) have been studied individually; however, we considered a panel of proteins to investigate AAA prognosis and its potential to improve predictive accuracy. Using a prospectively recruited cohort of patients with/without AAA (n = 452), we conducted a prognostic study to develop a model that accurately predicts AAA outcomes using clinical features and circulating biomarker levels. Serum concentrations of 9 biomarkers were measured at baseline, and the cohort was followed for 2 years. The primary outcome was major adverse aortic event (MAAE; composite of rapid AAA expansion [>0.5 cm/6 months or >1 cm/12 months], AAA intervention, or AAA rupture). Using 10-fold cross-validation, we trained a random forest model to predict 2 year MAAE using (1) clinical characteristics, (2) biomarkers, and (3) clinical characteristics and biomarkers. Two-year MAAE occurred in 114 (25%) patients. Two proteins were significantly elevated in patients with AAA compared with those without AAA (angiopoietin-2 and aggrecan), composing the protein panel. For predicting 2 year MAAE, our random forest model achieved area under the receiver operating characteristic curve (AUROC) 0.74 using clinical features alone, and the addition of the 2-protein panel improved performance to AUROC 0.86. Using a combination of clinical/biomarker data, we developed a model that accurately predicts 2 year MAAE.

ATG4B as a novel biomarker for abdominal aortic aneurysm: integrated evaluation through experimental and bioinformatics analyses.

Autophagy related gene 4B (ATG4B) plays a central role in autophagy machinery, but its clinical relevance to AAA remains unknown. In this study, 205 AAA patients and 205age- and sex-matched controls were included to detect the serum ATG4B levels. Meanwhile, abdominal aortic specimens from 24 AAA patients and 6 human organ donors were collected to evaluate the mRNA and in situ protein expression of ATG4B. We observed significantly higher ATG4B mRNA and protein expression levels in AAA group compared to those in control group, with a positive correlation between mRNA levels and serum/in situ protein levels (serum, r = 0.518, P = 0.010; in situ, r = 0.453, P = 0.026). Serum ATG4B exhibited the diagnostic potential for AAA (AUC = 0.702, sensitivity = 75.6%) and intraluminal thrombus recognition (AUC = 0.602, sensitivity = 67.9%). Logistic regression revealed a significant association between elevated serum ATG4B and an increased risk of AAA and intraluminal thrombus formation. Deceased patients displayed higher baseline serum ATG4B levels, which could predict postoperative mortality (HR = 1.028, 95%CI = 1.007-1.049, P = 0.009, AUC = 0.612, sensitivity = 84.6%). The bioinformatics analysis suggested that ATG4B may modulate cellular autophagy and influence pathways associated with inflammation, lipid metabolism, or apoptosis, thereby contributing to the occurrence and development of AAA. The drug-gene interaction network identified 13 potential therapeutic drugs targeting ATG4B. In conclusion, ATG4B may serve as a promising biomarker for the diagnosis and prognostic assessment of AAA patients and play a key role in the pathogenesis of AAA.

Clinical value of serum miR-1-3p as a potential circulating biomarker for abdominal aortic aneurysm

Background Although abdominal aortic aneurysm (AAA) is associated with life-threatening complications, there are still limited reliable biomarkers for diagnostic purpose. MicroRNAs (miRNAs) have been proposed as the potential diagnostic and risk stratification markers of AAA patients, and we aim to evaluate the serum level of miR-1-3p and its diagnostic value in AAA. Methods This study included 200 AAA patients and 200 controls. Demographic data and clinical information were collected from the subjects’ medical records. Individual image analyses of AAA morphology were determined based on computed tomography angiography (CTA). The levels of serum miRNA expression were detected by quantitative real-time PCR. Bioinformatics tools were used to identify the target genes of miR-1-3p and their potential biological functions were further enriched. Results Serum miR-1-3p levels in the AAA group were significantly lower when compared with those in the control group in overall and subgroup comparisons. It was negatively related to WBC, CRP, maximal aneurysm diameter, area, and volume in AAA patients. Circulating miR-1-3p levels could significantly discriminate between AAA patients and healthy individuals with an area under the curve (AUC) of 0.672 (95% CI = 0.619-0.724, p < 0.001), a sensitivity of 84.5% and a specificity of 45.5%. Serum miR-1-3p was associated with a reduced risk of AAA even after adjustment for possible risk factors (OR = 0.440 per unit increase, 95% CI = 0.301-0.643, p < 0.001). And low levels of serum miR-1-3p could significantly elevate the risk of AAA in both univariate and multivariate logistic regression analyses with ORs of 4.076 and 4.136, respectively (all p < 0.001). Further GO enrichment analysis revealed that miR-1-3p was mainly involved in negative regulation of apoptotic process, sprouting angiogenesis, angiogenesis, positive regulation of blood vessel endothelial cell migration, positive regulation of cell proliferation, regulation of cell shape, etc. Conclusions MiR-1-3p can be used as a promising circulating biomarker in the development of AAA, and it may participate in multiple biological processes to play a crucial role in AAA pathogenesis.

Abstract 278: Ccr2 Inhibition Impacts Abdominal Aortic Aneurysm Rupture In Rodents

Background: There is growing evidence that monocyte chemoattractant protein (MCP-1) / C-C chemokine receptor type 2 (CCR2) axis crucially affects the initiation and progression of abdominal aortic aneurysm (AAA). We hypothesize that inhibition of CCR2 may prevent AAA inflammation and rupture. Methods: 40 Male and 49 female Sprague-Dawley rats underwent intraluminal infrarenal abdominal aortic exposure to elastase to induce AAA. Rats received daily β-aminopropionitrile to promote AAA rupture. On post-operative day 3 (POD3), a treatment group (15 males, 17 females) received daily oral gavage of a CCR2 inhibitor (CCR2i; RS-504393), and a control group (25 males, 32 females) received no CCR2i. On POD6, both groups underwent PET/CT with a CCR2 targeting radiotracer 64 Cu-DOTA-ECL1i. In addition, AAA tissue cytokine/chemokine arrays were evaluated. Incidence of AAA rupture was evaluated in the remaining surviving rats until POD14 (Figure 1A). Results: Compared with controls, the incidence of AAA rupture was reduced in treated male AAA rats (0% vs 56%, p &lt;0.001; and tended to decreased in treated female AAA rats (18% vs 42%, p =0.09;). PET/CT demonstrated that male and female treatment groups had significantly decreased 64 Cu-DOTA-ECL1i uptake in AAAs ( p= 0.02 for male AAAs , p &lt;0.001 for females, Figure 1B). All cytokines, including MCP-1, RANTES, IL-17A, IL-18, IL-1B, IL-6, IL-10, except TNF-a were significantly reduced in the male treatment group compared to control group ( p &lt;0.05; Figure 1C). Interestingly, in the female treatment group, IL-1B was significantly decreased ( p &lt;0.05), and RANTES was significantly increased ( p &lt;0.05). Conclusion: In rats, CCR2 appears to be a promising theranostic biomarker for AAAs. CCR2i can greatly impact AAA tissue inflammation and reduces the incidence of AAA rupture. Differences between male and female rats suggest that CCR2 signaling may be different in AAA between sexes and highlights future avenues of further investigation.

Identification of Novel Biomarkers for Abdominal Aortic Aneurysm Promoted by Obstructive Sleep Apnea

We sought to find new biomarkers for abdominal aortic aneurysms (AAA) caused by chronic intermittent hypoxia (CIH). The AAA mice model was created using Ang II. The mice were divided into normoxic and CIH groups. The structure of AAA was observed using abdominal ultrasonography, Elastica van Gieson (EVG), and hematoxylin and eosin (HE) staining. The expression of ɑ-SMA was investigated using immunohistochemistry. The novel biomarkers were screened using bioinformatics analysis. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to verify the expression of novel genes in both normal oxygen and CIH. CIH appears to cause greater aortic dilation, higher AAA incidence, lower survival rate, thicker vessel wall, and more brittle elastic lamellae when compared to controls. The immunohistochemistry results showed that the expression of ɑ-SMA in the CIH group was reduced significantly. Four novel genes, including Homer2, Robo2, Ehf, and Asic1, were found to be differentially expressed between normal oxygen and CIH using qRT-PCR, indicating the same trend as bioinformatics analysis. We discovered that CIH could hasten the occurrence and progression of AAA. Four genes (Homer2, Robo2, Ehf, and Asic1) may be novel biomarkers for AAA, which could aid in the search for new therapies for patients with AAA caused by CIH.

Identification of PTPN22 as a potential genetic biomarker for abdominal aortic aneurysm.

Abdominal aortic aneurysm (AAA) is a severe life-threatening disease that is generally asymptomatic and is diagnosed at a very late stage. The genetic component underpinning AAA is considerable, with an estimated heritability of up to 70%. Therefore, identifying genetic biomarkers for AAA is valuable for predicting high-risk populations. We used integrative bioinformatics and cellular AAA model-based validation to reveal that the gene encoding protein tyrosine phosphatase non-receptor type 22 (PTPN22) may be a potentially useful diagnostic biomarker for AAA. Integrative bioinformatics analyses of clinical specimens showed that PTPN22 expression was consistently upregulated in aortic tissues and peripheral blood mononuclear cells (PBMCs) derived from patients with AAA. Moreover, transcriptomics data revealed that PTPN22 is a potential biomarker for AAA with limited diagnostic value in patients with thoracic aortic aneurysm/dissection. Single-cell RNA sequencing-based findings further highlight PTPN22 expression in aortic immune cells and vascular smooth muscle cells (VSMCs) is consistently upregulated in patients with AAA. A cellular AAA model was eventually employed to verify the increase in PTPN22 expression. Collectively, the results indicate that PTPN22 could be a potentially useful diagnostic biomarker for AAA.

Identification of Novel Plasma Biomarkers for Abdominal Aortic Aneurysm by Protein Array Analysis.

Abdominal aortic aneurysm (AAA) is a potentially life-threatening disease that is common in the aging population. Currently, there are no approved diagnostic biomarkers or therapeutic drugs for AAA. We aimed to identify novel plasma biomarkers or potential therapeutic targets for AAA using a high-throughput protein array-based method. Proteomics expression profiles were investigated in plasma from AAA patients and healthy controls (HC) using 440-cytokine protein array analysis. Several promising biomarkers were further validated in independent cohorts using enzyme-linked immunosorbent assay (ELISA). Thirty-nine differentially expressed plasma proteins were identified between AAA and HC. Legumain (LGMN) was significantly higher in AAA patients and was validated in another large cohort. Additionally, "AAA without diabetes" (AAN) patients and "AAA complicated with type 2 diabetes mellitus" (AAM) patients had different cytokine expression patterns in their plasma, and nine plasma proteins were differentially expressed among the AAN, AAM, and HC subjects. Delta-like protein 1 (DLL1), receptor tyrosine-protein kinase erbB-3 (ERBB3), and dipeptidyl peptidase 4 (DPPIV) were significantly higher in AAM than in AAN. This study identified several promising plasma biomarkers of AAA. Their role as therapeutic targets for AAA warrants further investigation.

TCF7L1 Accelerates Smooth Muscle Cell Phenotypic Switching and Aggravates Abdominal Aortic Aneurysms

Phenotypic switching of vascular smooth muscle cells is a central process in abdominal aortic aneurysm (AAA) pathology. We found that knockdown TCF7L1 (transcription factor 7-like 1), a member of the TCF/LEF (T cell factor/lymphoid enhancer factor) family of transcription factors, inhibits vascular smooth muscle cell differentiation. This study hints at potential interventions to maintain a normal, differentiated smooth muscle cell state, thereby eliminating the pathogenesis of AAA. In addition, our study provides insights into the potential use of TCF7L1 as a biomarker for AAA.

Identification of biomarkers and analysis of infiltrated immune cells in stable and ruptured abdominal aortic aneurysms.

ObjectivesThe mortality rate of abdominal aortic aneurysm (AAA) is extremely high in the older population. This study aimed to identify potential biomarkers of AAA and aortic rupture and analyze infiltration of immune cells in stable and ruptured AAA samples.MethodsRaw data of GSE47472, GSE57691, and GSE98278 were downloaded. After data processing, the co-expression gene networks were constructed. Gene Ontology and pathway enrichment analysis of AAA- and aortic rupture-related gene modules were conducted using the Database for Annotation, Visualization, and Integrated Discovery. Gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) were used for further enrichment analysis. The CIBERSORT tool was used to analyze the relative abundance of immune cells in samples. Differentially expressed immune-related genes were analyzed between different samples. Predictive models were constructed via extreme gradient boosting, and hub genes were identified according to feature importance.ResultsBlue and yellow modules were significantly related to AAA, and genes in these modules were associated with the aortic wall and immune response, respectively. In terms of aortic rupture, the most relevant module was significantly enriched in the inflammatory response. The results of GSEA and GSVA suggested that immune cells and the inflammatory response were involved in the development of AAA and aortic rupture. There were significant differences in the infiltration of immune cells and expression levels of immune-related genes among different samples. NFKB1 might be an important transcription factor mediating the inflammatory response of AAA and aortic rupture. After the construction of a predictive model, CD19, SELL, and CCR7 were selected as hub genes for AAA whereas OAS3, IFIT1, and IFI44L were identified as hub genes for aortic rupture.ConclusionWeakening of the aortic wall and the immune response both contributed to the development of AAA, and the inflammatory response was closely associated with aortic rupture. The infiltration of immune cells was significantly different between different samples. NFKB1 might be an important transcription factor in AAA and aortic rupture. CD19, SELL, and CCR7 had potential diagnostic value for AAA. OAS3, IFIT1, and IFI44L might be predictive factors for aortic rupture.

MiR-30c-1-3p targets matrix metalloproteinase 9 involved in the rupture of abdominal aortic aneurysms

Abdominal aortic aneurysm (AAA) can be fatal if ruptured, but there is no predictive biomarker. Our aim was to evaluate the prognostic potential of microRNAs (miRNAs/miRs) in an AAA mouse model and patients with unruptured AAA (URAAA) and ruptured AAA (RAAA). Among the 64 miRNAs differentially expressed in mice with AAA compared to control, miR-30c-1-3p, miR-432-3p, miR-3154, and miR-379-5p had high homology with human miRNAs. MiR-30c-1-3p plasma levels were significantly lower in patients with RAAA than in those with URAAA or control and tended to negatively correlate with the maximum aortic diameter (r = −0.3153, P = 0.06109). MiR-30c-1-3p targeted matrix metalloproteinase (MMP)-9 mRNA through the coding region and downregulated its expression in vitro. MMP-9 plasma concentrations were significantly higher in the RAAA group than in the URAAA group (P < 0.001) and were negatively associated with miR-30c-1-3p levels (r = −0.3671, P = 0.01981) and positively–with the maximal aortic diameter (r = 0.6251, P < 0.0001). The optimal cutoff values for MMP-9 expression and the maximal aortic diameter were 461.08 ng/ml and 55.95 mm, with areas under the curve of 0.816 and 0.844, respectively. Our results indicate that plasma levels of miR-30c-1-3p and MMP-9 may be candidate biomarkers of AAA progression.Key messagesDownregulation of miR-30c-1-3p expression and upregulation of its potential target MMP-9 are predictors of the devastation of AAA.Downregulation of miR-30c-1-3p expression and its downstream impact on MMP-9 have a potential on predicting the development and rupture of AAA.

Single-Cell Sequencing Analysis and Multiple Machine Learning Methods Identified G0S2 and HPSE as Novel Biomarkers for Abdominal Aortic Aneurysm.

Identifying biomarkers for abdominal aortic aneurysms (AAA) is key to understanding their pathogenesis, developing novel targeted therapeutics, and possibly improving patients outcomes and risk of rupture. Here, we identified AAA biomarkers from public databases using single-cell RNA-sequencing, weighted co-expression network (WGCNA), and differential expression analyses. Additionally, we used the multiple machine learning methods to identify biomarkers that differentiated large AAA from small AAA. Biomarkers were validated using GEO datasets. CIBERSORT was used to assess immune cell infiltration into AAA tissues and investigate the relationship between biomarkers and infiltrating immune cells. Therefore, 288 differentially expressed genes (DEGs) were screened for AAA and normal samples. The identified DEGs were mostly related to inflammatory responses, lipids, and atherosclerosis. For the large and small AAA samples, 17 DEGs, mostly related to necroptosis, were screened. As biomarkers for AAA, G0/G1 switch 2 (G0S2) (Area under the curve [AUC] = 0.861, 0.875, and 0.911, in GSE57691, GSE47472, and GSE7284, respectively) and for large AAA, heparinase (HPSE) (AUC = 0.669 and 0.754, in GSE57691 and GSE98278, respectively) were identified and further verified by qRT-PCR. Immune cell infiltration analysis revealed that the AAA process may be mediated by T follicular helper (Tfh) cells and the large AAA process may also be mediated by Tfh cells, M1, and M2 macrophages. Additionally, G0S2 expression was associated with neutrophils, activated and resting mast cells, M0 and M1 macrophages, regulatory T cells (Tregs), resting dendritic cells, and resting CD4 memory T cells. Moreover, HPSE expression was associated with M0 and M1 macrophages, activated and resting mast cells, Tregs, and resting CD4 memory T cells. Additional, G0S2 may be an effective diagnostic biomarker for AAA, whereas HPSE may be used to confer risk of rupture in large AAAs. Immune cells play a role in the onset and progression of AAA, which may improve its diagnosis and treatment.

D-Dimer Is a Diagnostic Biomarker of Abdominal Aortic Aneurysm in Patients With Peripheral Artery Disease.

BackgroundEtiology and risk factors of peripheral artery disease (PAD) include age, smoking, and hypertension, etc. , which are shared by an abdominal aortic aneurysm (AAA). Concomitance with AAA in patients with PAD is not rare but is easily overlooked in the clinical situation, though management strategies are altered totally. This study aims to investigate diagnostic biomarkers for the prediction of AAA in patients with PAD.MethodsA total of 684 patients diagnosed with AAA and/or PAD were enrolled and analyzed retrospectively. Each patient with PAD and AAA was gender and age-matched. Demographic data, medical history, and serum laboratory test profiles were obtained. Statistical analysis was performed to determine diagnostic biomarkers of AAA in patients with PAD.ResultsFirstly, 320 patients with PAD-only and 320 patients with AAA-only were compared. Levels of bilirubin and D-Dimer were decreased, while the incidence of diabetes mellitus, levels of fibrinogen, and platelet count were increased significantly in patients with PAD-only compared with those in patients with AAA-only (P < 0.001). Next, 364 patients with PAD (44 patients with AAA) and 364 patients with AAA (44 patients with PAD) were compared. Multivariate logistic regression analysis confirmed the differential distribution of bilirubin, D-dimer, fibrinogen, and platelet count between patients with AAA and patients with PAD (P < 0.05). Receiver operator curves (ROC) showed that the area under the curve (AUC) of total bilirubin, direct bilirubin, D-dimer, fibrinogen, and platelet count was 0.6113, 0.5849, 0.7034, 0.6473, and 0.6785, respectively. Finally, to further validate the predictive efficacy of mentioned markers, a multivariable logistics regression analysis was performed between the PAD only group and the PAD with AAA group. The results suggested increased levels of D-dimer in the PAD with AAA group compared to the PAD only group (OR: 2.630, 95% CI:1.639–4.221; P < 0.001). In particular, the Youden index suggested that the cut-off value of D-dimer for predicting AAA in patients with PAD was 0.675 mg/L with a sensitivity of 76.9% and a specificity of 84.9% (AUC = 0.8673; 95% CI, 0.8106–0.9240, P < 0.001). In all 364 patients with PAD, 41.46% patients were diagnosed AAA when D-dimer is >0.675 mg/L, while only 3.55% patients were diagnosed AAA when D-dimer ≤ 0.675 mg/L.ConclusionsPAD and AAA exert different clinical and serum profiles; D-dimer (>0.675 mg/L) is a reliable biomarker for the prediction of AAA in patients with PAD.

Current-Volt Biosensing “Cystatin C” on Carbon Nanowired Interdigitated Electrode Surface: A Clinical Marker Analysis for Bulged Aorta

A carbon nanowire-modified surface with interdigitated electrode (IDE) sensing system was introduced to identify abdominal aortic aneurysm biomarker “papain,” also known as cysteine protease, used as the capture probe to identify Cystatin C. Papain was immobilized through the covalent integration of amine group on papain and the carboxyl group with carbon nanowire. This papain-modified electrode surface was utilized to detect the different concentrations of Cystatin C (100 pg/mL to 3.2 ng/mL). The interaction between papain and Cystatin C was monitored using a picoammeter, and the response curves were compared. With increasing Cystatin C concentrations, the total current levels were gradually increased with a linear range from 200 pg/mL to 3.2 ng/mL, and the current differences were plotted and the detection limit of Cystatin C was calculated as 200 pg/mL. The averaging of three independent experiments (n = 3) was made with 3δ estimation, and the determination coefficient was y = 1.8477 × 0.7303 and R2 = 0.9878. Furthermore, control experiments with creatinine and gliadin failed to bind the immobilized papain, indicating the specific detection of Cystatin C.

Extracellular Vesicle-derived MicroRNAs From Human Abdominal Aortic Aneurysm Associate With Proaneurysmal Cell Signaling and Senescence Pathways

Abdominal aortic aneurysm (AAA) is associated with significant postrupture mortality in aging populations. Management of AAAs is limited to watchful waiting and surgical repair, which stems from our limited understanding of AAA disease processes. Current research foci including extracellular vesicles (EVs; nano-sized packages of proteins, RNAs, and lipids that facilitate cell-cell communication) may aid in discovering novel AAA biomarkers and therapies. To characterize this regulatory cargo, we isolated EVs from human AAA tissue or control aortic punch biopsies and profiled EV content with microRNA (miRNA) sequencing to identify pathway dysregulation.

Association of miRNA-145 Single Nucleotide Polymorphisms in Abdominal Aortic Aneurysms

MicroRNAs (miRNAs) are non-coding RNA molecules that exert post-transcriptional gene expression regulation in response to cellular or environmental changes. Genetic variation affects their synthesis and cellular actions, and single nucleotide polymorphisms (SNPs) are one example of genetic variants studied in relation to various diseases. Literature indicates that the differentially expressed miRNA-145 in patients' serum is an essential biomarker for abdominal aortic aneurysm (AAA). However, the correlation between specific miR-145 genetic polymorphisms with AAA susceptibility is inadequately studied. Eighty-seven AAA patients and 122 healthy controls were recruited. Peripheral blood samples were genotyped for miRNA-145 SNPs; rs55945735, rs73798217 and rs353291. The GG genotype of the rs55945735 polymorphism (p=0.047) and the AG genotype of the rs353291 polymorphism (p=0.036) were overrepresented in AAA patients compared to healthy individuals, revealing an association with susceptibility to AAA development. SNPs rs55945735 and rs353291 are associated with AAA susceptibility.

MicroRNASeq Target Analysis and Validation by Real-Time PCR in Abdominal Aortic Aneurysm

Background/ Objective: Abdominal aortic aneurysm (AAA) is an epigenetic event characterized by chronic inflammation and degeneration of the aortic wall leading to catastrophic rupture. Cigarette smoke exposure is the greatest environmental risk factor associated with AAA development. MicroRNAs (miRNA) regulate gene expression and may play a role in smoking-induced aortic inflammation. Epigenetic changes could include dysregulation of miRNA, causing post-transcriptional abnormalities pathogenic to AAA. &#x0D; &#x0D; Methods: miRNA was extracted from plasma of 24 AAA patients and 7 risk factor matched (RFM) patients and analyzed by RNA sequencing. We compared previous (PS) and current smokers (CS) within and between both patient cohorts. Differential expression of miRNAs was analyzed by ANOVA (p≤ 0.05). Potential targets of significant differentially expressed miRNAs were predicted using cross-analysis of TargetScan and miRanda databases. &#x0D; &#x0D; Results: Analysis revealed 7 significantly different miRNAs between AAA CS and AAA PS and 6 significantly different miRNAs between RFM CS and RFM PS. Of greatest significance, hsa-miR-223-3p was significantly downregulated as an effect of smoking cessation in AAA PS compared to AAA CS (p=0.000263), while also showing clinically relevant expression levels. Target genes of hsa-miR-223-3p include pro-inflammatory factors IL-6, TNFα, TGFβ, and MCP-1. Speculatively, as tissue levels of miR-223 tend to inversely correlate with plasma levels, we could hypothesize that the observed plasma upregulation of hsa-miR-223-3p in AAA CS contributes to the pro-inflammatory microenvironment of aortic tissue. &#x0D; &#x0D; Conclusion: Cigarette smoke contributes to epigenetic changes impacting factors of immune regulation or inflammation, eventually leading to disease states such as AAA. Inflammatory-related hsa-miR-223-3p is upregulated in AAA CS, suggesting its potential role in the disease course. &#x0D; &#x0D; Implications: Upregulation of hsa-miR-223-3p in AAA CS offers a link between disease state and the number one environmental factor attributed to AAA. This signature miRNA could serve as a biomarker for AAA or as a potential therapy target.

Identification of potential novel biomarkers for abdominal aortic aneurysm based on comprehensive analysis of circRNA-miRNA-mRNA networks.

Abdominal aortic aneurysm (AAA) is a life-threatening disorder and, therefore, investigation into its underlying mechanisms in light of the competing endogenous RNAs (ceRNAs) hypothesis has gradually increased. However, there is still lacking systematic analysis on AAA-associated circular RNA (circRNA)-microRNA (miRNA/miR)-messenger RNA (mRNA) interaction networks based on bioinformatics methods. The present study attempted to identify novel molecular biomarkers for AAA by profiling circRNA-miRNA-mRNA networks using three public microarray datasets (GSE7084, GSE57691 and GSE144431). A total of 135 differentially expressed genes (DEGs) and 142 differentially expressed circRNAs were detected using the limma R package with the statistical threshold of P<0.05 and |log2fold change (FC)| >1.5. In addition, 12 circRNA-miRNA-mRNA axes were identified to construct upregulated and downregulated ceRNA networks using Cytoscape. Based on molecular complex detection algorithm, (hsa_circ_0057691/0092108/0006845/0082182)- miR-330-5p-calponin 1 (CNN1) and (hsa_circ_0061482/0011450/0008351/0004121)-miR-326-CD8a molecule (CD8A) were recognized as the center axes in ceRNA networks. Reverse transcription-quantitative PCR results verified the significant downregulation of CNN1 and upregulation of CD8A in human AAA tissues (P<0.05). In addition, four upregulated circRNA/mRNA axes, and five downregulated circRNA/mRNA axes were revealed to have possible biological functions in the pathogenesis of AAA using the Cytoscape software. Receiver operating characteristic analysis demonstrated the accuracy of these nine DEGs involved in these axes for AAA diagnosis with area under the curves >0.80. The present study revealed novel circRNA-miRNA-mRNA networks associated with AAA, especially for CNN1 and CD8A axes with the potential function of ‘focal adhesion’ and ‘immune response’, respectively. Overall, the present findings may provide evidence to explore the implicated ceRNAs in the molecular mechanisms and as novel biomarkers for AAA.

Neutrophils as Regulators and Biomarkers of Cardiovascular Inflammation in the Context of Abdominal Aortic Aneurysms.

Neutrophils represent up to 70% of circulating leukocytes in healthy humans and combat infection mostly by phagocytosis, degranulation and NETosis. It has been reported that neutrophils are centrally involved in abdominal aortic aneurysm (AAA) pathogenesis. The natural course of AAA is growth and rupture, if left undiagnosed or untreated. The rupture of AAA has a very high mortality and is currently among the leading causes of death worldwide. The use of noninvasive cardiovascular imaging techniques for patient screening, surveillance and postoperative follow-up is well established and recommended by the current guidelines. Neutrophil-derived biomarkers may offer clinical value to the monitoring and prognosis of AAA patients, allowing for potential early therapeutic intervention. Numerous promising biomarkers have been studied. In this review, we discuss neutrophils and neutrophil-derived molecules as regulators and biomarkers of AAA, and our aim was to specifically highlight diagnostic and prognostic markers. Neutrophil-derived biomarkers may potentially, in the future, assist in determining AAA presence, predict size, expansion rate, rupture risk, and postoperative outcome once validated in highly warranted future prospective clinical studies.