Management of Abdominal Aortic Aneurysms

LXRα Promotes Abdominal Aortic Aneurysm Formation Through UHRF1 Epigenetic Modification of miR-26b-3p

BACKGROUND

Abdominal aortic aneurysm (AAA) is a severe aortic disease without effective pharmacological approaches. The nuclear hormone receptor LXRα (liver X receptor α), encoded by the NR1H3 gene, serves as a critical transcriptional mediator linked to several vascular pathologies, but its role in AAA remains elusive.

METHODS

Through integrated analyses of human and murine AAA gene expression microarray data sets, we identified NR1H3 as a candidate gene regulating AAA formation. To investigate the role of LXRα in AAA formation, we used global Nr1h3-knockout and vascular smooth muscle cell-specific Nr1h3-knockout mice in 2 AAA mouse models induced with angiotensin II (1000 ng·kg·min; 28 days) or calcium chloride (CaCl2; 0.5 mol/L; 42 days).

RESULTS

Upregulated LXRα was observed in the aortas of patients with AAA and in angiotensin II- or CaCl2-treated mice. Global or vascular smooth muscle cell-specific Nr1h3 knockout inhibited AAA formation in 2 mouse models. Loss of LXRα function prevented extracellular matrix degeneration, inflammation, and vascular smooth muscle cell phenotypic switching. Uhrf1, an epigenetic master regulator, was identified as a direct target gene of LXRα by integrated analysis of transcriptome sequencing and chromatin immunoprecipitation sequencing. Susceptibility to AAA development was consistently enhanced by UHRF1 (ubiquitin-like containing PHD and RING finger domains 1) in both angiotensin II- and CaCl2-induced mouse models. We then determined the CpG methylation status and promoter accessibility of UHRF1-mediated genes using CUT&Tag (cleavage under targets and tagmentation), RRBS (reduced representation bisulfite sequencing), and ATAC-seq (assay for transposase-accessible chromatin with sequencing) in vascular smooth muscle cells, which revealed that the recruitment of UHRF1 to the promoter of miR-26b led to DNA hypermethylation accompanied by relatively closed chromatin states, and caused downregulation of miR-26b expression in AAA. Regarding clinical significance, we found that underexpression of miR-26b-3p correlated with high risk in patients with AAA. Maintaining miR-26b-3p expression prevented AAA progression and alleviated the overall pathological process.

CONCLUSIONS

Our study reveals a pivotal role of the LXRα/UHRF1/miR-26b-3p axis in AAA and provides potential biomarkers and therapeutic targets for AAA.

A prospective longitudinal study of risk factors for abdominal aortic aneurysm

The aim of this study was to identify risk factors for abdominal aortic aneurysm (AAA) from the largest Welsh screening cohort to date. Patients were recruited from 1993 (to 2015) as part of the South East Wales AAA screening programme through general practitioners. Demographic data and risk factors were collected by means of a self-report questionnaire. Statistical tests were performed to determine whether associations could be observed between AAA and potential risk factors. Odds ratios (OR) were also calculated for each of the risk factors identified. A total of 6879 patients were included in the study. Two hundred and seventy-five patients (4.0%) presented with AAA, of which 16% were female and 84% were male. Patients with AAA were older than the (no AAA) control group (p < 0.0001). The following risk factors were identified for AAA: family history of AAA (p < 0.0001); history of vascular surgery (p < 0.0001), cerebrovascular accident (p < 0.0001), coronary heart disease (p < 0.0001), diabetes (p < 0.0001), medication (p = 0.0018), claudication (p < 0.0001), smoking history (p = 0.0001) and chronic obstructive pulmonary disorder (p = 0.0007). AAA is associated with classical vascular risk factors, in addition to other less-well-documented risk factors including previous vascular surgery. These findings have practical implications with the potential to improve future clinical screening of patients in order to reduce AAA mortality.

Visualizing the crucial roles of plasma membrane and peroxynitrite during abdominal aortic aneurysm using two-photon fluorescence imaging

Peroxynitrite (ONOO-) and cell plasma membrane (CPM) are two key factors in cell pyroptosis during the progression of abdominal aortic aneurysm (AAA). However, their combined temporal and spatial roles in initiating AAA pathogenesis remain unclear. Herein, we developed a two-photon fluorescence probe, BH-Vis, enabling real-time dynamic detection of CPM and ONOO- changes, and revealing their interplay in AAA. BH-Vis precisely targets CPM with reduced red fluorescence intensity correlating with diminished CPM tension. Concurrently, a blue shift of the fluorescence signal of BH-Vis occurs in response to ONOO- offering a reliable ratiometric detection mode with enhanced accuracy by minimizing external testing variables. More importantly, two photon confocal imaging with palmitic acid (PA) and ganglioside (GM1) manipulation, which modulating cell pyroptosis, showcases reliable fluorescence fluctuations. This groundbreaking application of BH-Vis in a mouse AAA model demonstrates its significant potential for accurately identifying cell pyroptosis levels during AAA development.

A Dual-Targeting, Multi-Faceted Biocompatible Nanodrug Optimizes the Microenvironment to Ameliorate Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a highly lethal cardiovascular disease that currently lacks effective pharmacological treatment given the complex pathophysiology of the disease. Here, single-cell RNA-sequencing data from patients with AAA and a mouse model are analyzed, which reveals pivotal pathological changes, including the M1-like polarization of macrophages and the loss of contractile function in smooth muscle cells (SMCs). Both cell types express the integrin αvβ3, allowing for their dual targeting with a single rationally designed molecule. To this end, a biocompatible nanodrug, which is termed EVMS@R-HNC, that consists of the multifunctional drug everolimus (EVMS) encapsulated by the hepatitis B virus core protein modifies to contain the RGD sequence to specifically bind to integrin αvβ3 is designed. Both in vitro and in vivo results show that EVMS@R-HNC can target macrophages as well as SMCs. Upon binding of the nanodrug, the EVMS is released intracellularly where it exhibits multiple functions, including inhibiting M1 macrophage polarization, thereby suppressing the self-propagating inflammatory cascade and immune microenvironment imbalance, while preserving the normal contractile function of SMCs. Collectively, these results suggest that EVMS@R-HNC presents a highly promising therapeutic approach for the management of AAA.

NINJ1 Facilitates Abdominal Aortic Aneurysm Formation via Blocking TLR4-ANXA2 Interaction and Enhancing Macrophage Infiltration

Abdominal aortic aneurysm (AAA) is a common and potentially life-threatening condition. Chronic aortic inflammation is closely associated with the pathogenesis of AAA. Nerve injury-induced protein 1 (NINJ1) is increasingly acknowledged as a significant regulator of the inflammatory process. However, the precise involvement of NINJ1 in AAA formation remains largely unexplored. The present study finds that the expression level of NINJ1 is elevated, along with the specific expression level in macrophages within human and angiotensin II (Ang II)-induced murine AAA lesions. Furthermore, Ninj1flox/flox and Ninj1flox/floxLyz2-Cre mice on an ApoE-/- background are generated, and macrophage NINJ1 deficiency inhibits AAA formation and reduces macrophage infiltration in mice infused with Ang II. Consistently, in vitro suppressing the expression level of NINJ1 in macrophages significantly restricts macrophage adhesion and migration, while attenuating macrophage pro-inflammatory responses. Bulk RNA-sequencing and pathway analysis uncover that NINJ1 can modulate macrophage infiltration through the TLR4/NF-κB/CCR2 signaling pathway. Protein-protein interaction analysis indicates that NINJ1 can activate TLR4 by competitively binding with ANXA2, an inhibitory interacting protein of TLR4. These findings reveal that NINJ1 can modulate AAA formation by promoting macrophage infiltration and pro-inflammatory responses, highlighting the potential of NINJ1 as a therapeutic target for AAA.

Unsupervised machine learning cluster analysis to identification EVAR patients clinical phenotypes based on radiomics

OBJECTIVE

This study used unsupervised machine learning (UML) cluster analysis to explore clinical phenotypes of endovascular aortic repair (EVAR) for abdominal aortic aneurysm (AAA) patients based on radiomics.

METHOD

We retrospectively reviewed 1785 patients with infra-renal AAA who underwent elective EVAR procedures between January 2010 and December 2020. Pyradiomics was used to extract the radiomics features. Statistical analysis was applied to determine the radiomics features that related to severe adverse events (SAEs) after EVAR. The selected features were used for UML cluster analysis in training set and validation in test set. Comparison of basic characteristics and radiomics features of different clusters. The Kaplan-Meier analysis was conducted to generate the cumulative incidence of freedom from SAEs rate.

RESULT

A total of 1180 patients were enrolled. During the follow-up, 353 patients experienced EVAR-related SAEs. In total, 1223 radiomics features were extracted from each patient, of which 23 radiomics features were finally preserved to identify different clinical phenotypes. 944 patients were allocated to the training set. Three clusters were identified in training set, in which patients had identical clinical characteristics and morphological features, while varied considerably of selected radiomics features. This encouraging performance was further approved in the test set. In addition, each cluster was well differentiated from other clusters and Kaplan-Meier analysis showed significant differences of freedom from SAEs rate between different clusters both in the training (p = .0216) and test sets (p = .0253).

CONCLUSION

Based on radiomics, UML cluster analysis can identify clinical phenotypes in EVAR patients with distinct long-term outcomes.

Assessing the causal relationship between circulating immune cells and abdominal aortic aneurysm by bi-directional Mendelian randomization analysis

Although there is an association between abdominal aortic aneurysm (AAA) and circulating immune cell phenotypes, the exact causal relationship remains unclear. This study aimed to explore the causal relationships between immune cell phenotypes and AAA risk using a bidirectional two-sample Mendelian randomization approach. Data from genome-wide association studies pertaining to 731 immune cell traits and AAA were systematically analyzed. Using strict selection criteria, we identified 339 immune traits that are associated with at least 3 single nucleotide polymorphisms. A comprehensive MR analysis was conducted using several methods including Inverse Variance Weighted, Weighted Median Estimator, MR-Egger regression, Weighted Mode, and Simple Median methods. CD24 on switched memory cells (OR = 0.922, 95% CI 0.914-0.929, P = 2.62e-79) at the median fluorescence intensities level, and SSC-A on HLA-DR + natural killer cells (OR = 0.873, 95% CI 0.861-0.885, P = 8.96e-81) at the morphological parameter level, exhibited the strongest causal associations with AAA. In the reverse analysis, no significant causal effects of AAA on immune traits were found. The study elucidates the causal involvement of multiple circulating immune cell phenotypes in AAA development, signifying their potential as diagnostic markers or therapeutic targets. These identified immune traits may be crucial in modulating AAA-related inflammatory pathways.

Comprehensive transcriptomic analysis unveils macrophage-associated genes for establishing an abdominal aortic aneurysm diagnostic model and molecular therapeutic framework

BACKGROUND

Abdominal aortic aneurysm (AAA) is a highly lethal cardiovascular disease. The aim of this research is to identify new biomarkers and therapeutic targets for the treatment of such deadly diseases.

METHODS

Single-sample gene set enrichment analysis (ssGSEA) and CIBERSORT algorithms were used to identify distinct immune cell infiltration types between AAA and normal abdominal aortas. Single-cell RNA sequencing data were used to analyse the hallmark genes of AAA-associated macrophage cell subsets. Six macrophage-related hub genes were identified through weighted gene co-expression network analysis (WGCNA) and validated for expression in clinical samples and AAA mouse models. We screened potential therapeutic drugs for AAA through online Connectivity Map databases (CMap). A network-based approach was used to explore the relationships between the candidate genes and transcription factors (TFs), lncRNAs, and miRNAs. Additionally, we also identified hub genes that can effectively identify AAA and atherosclerosis (AS) through a variety of machine learning algorithms.

RESULTS

We obtained six macrophage hub genes (IL-1B, CXCL1, SOCS3, SLC2A3, G0S2, and CCL3) that can effectively diagnose abdominal aortic aneurysm. The ROC curves and decision curve analysis (DCA) were combined to further confirm the good diagnostic efficacy of the hub genes. Further analysis revealed that the expression of the six hub genes mentioned above was significantly increased in AAA patients and mice. We also constructed TF regulatory networks and competing endogenous RNA networks (ceRNA) to reveal potential mechanisms of disease occurrence. We also obtained two key genes (ZNF652 and UBR5) through a variety of machine learning algorithms, which can effectively distinguish abdominal aortic aneurysm and atherosclerosis.

CONCLUSION

Our findings depict the molecular pharmaceutical network in AAA, providing new ideas for effective diagnosis and treatment of diseases.

Advances and challenges in regenerative therapies for abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a significant source of mortality worldwide and carries a mortality of greater than 80% after rupture. Despite extensive efforts to develop pharmacological treatments, there is currently no effective agent to prevent aneurysm growth and rupture. Current treatment paradigms only rely on the identification and surveillance of small aneurysms, prior to ultimate open surgical or endovascular repair. Recently, regenerative therapies have emerged as promising avenues to address the degenerative changes observed in AAA. This review briefly outlines current clinical management principles, characteristics, and pharmaceutical targets of AAA. Subsequently, a thorough discussion of regenerative approaches is provided. These include cellular approaches (vascular smooth muscle cells, endothelial cells, and mesenchymal stem cells) as well as the delivery of therapeutic molecules, gene therapies, and regenerative biomaterials. Lastly, additional barriers and considerations for clinical translation are provided. In conclusion, regenerative approaches hold significant promise for in situ reversal of tissue damages in AAA, necessitating sustained research and innovation to achieve successful and translatable therapies in a new era in AAA management.

Pentamethylquercetin attenuates angiotensin II-induced abdominal aortic aneurysm formation by blocking nuclear translocation of C/EBPβ at Lys253

BACKGROUND

Pentamethylquercetin (PMQ) is a natural polymethyl flavonoid that possesses anti-apoptotic and other biological properties. Abdominal aortic aneurysm (AAA), a fatal vascular disease with a high risk of rupture, is associated with phenotypic switching and apoptosis of medial vascular smooth muscle cells (VSMCs). This study aimed to investigate the protective effects of PMQ on the development of AAA and the underlying mechanism.

METHODS

ApoE-/- mice were continuously infused with angiotensin II (Ang II) for 4 weeks to develop the AAA model. Intragastric administration of PMQ was initiated 5 days before Ang II infusion and continued for 4 weeks. In vitro, VSMCs were cultured and pretreated with PMQ, stimulated with Ang II. Real-time PCR, western blotting, and immunofluorescence staining were used to examine the roles and mechanisms of PMQ on the phenotypic switching and apoptosis of VSMCs.

RESULTS

PMQ dose-dependently reduced the incidence of Ang II-induced AAA, aneurysm diameter enlargement, elastin degradation, VSMCs phenotypic switching and apoptosis. Furthermore, PMQ also inhibited phenotypic switching and apoptosis in Ang II-stimulated VSMCs. PMQ exerted protective effects by regulating the C/EBPβ/PTEN/AKT/GSK-3β axis. AAV-mediated overexpression of PTEN reduced the therapeutic effects of PMQ in the AAA model mice, suggesting that the effects of PMQ on Ang II-mediated AAA formation were related to the PTEN/AKT/GSK-3β axis. PMQ inhibited VSMCs phenotypic switching and apoptosis by bounding to C/EBPβ at Lys253 with hydrogen bond to regulate C/EBPβ nuclear translocation and PTEN/AKT/GSK-3β axis, thereby inhibiting Ang II-induced AAA formation.

CONCLUSIONS

Pentamethylquercetin inhibits angiotensin II-induced abdominal aortic aneurysm formation by bounding to C/EBPβ at Lys253. Therefore, PMQ prevents the formation of AAA and reduces the incidence of AAA.

Virtual Shape-Editing of Patient-Specific Vascular Models Using Regularized Kelvinlets

OBJECTIVE

Cardiovascular diseases, and the interventions performed to treat them, can lead to changes in the shape of patient vasculatures and their hemodynamics. Computational modeling and simulations of patient-specific vascular networks are increasingly used to quantify these hemodynamic changes, but they require modifying the shapes of the models. Existing methods to modify these shapes include editing 2D lumen contours prescribed along vessel centerlines and deforming meshes with geometry-based approaches. However, these methods can require extensive by-hand prescription of the desired shapes and often do not work robustly across a range of vascular anatomies. To overcome these limitations, we develop techniques to modify vascular models using physics-based principles that can automatically generate smooth deformations and readily apply them across different vascular anatomies.

METHODS

We adapt Regularized Kelvinlets, analytical solutions to linear elastostatics, to perform elastic shape-editing of vascular models. The Kelvinlets are packaged into three methods that allow us to artificially create aneurysms, stenoses, and tortuosity.

RESULTS

Our methods are able to generate such geometric changes across a wide range of vascular anatomies. We demonstrate their capabilities by creating sets of aneurysms, stenoses, and tortuosities with varying shapes and sizes on multiple patient-specific models.

CONCLUSION

Our Kelvinlet-based deformers allow us to edit the shape of vascular models, regardless of their anatomical locations, and parametrically vary the size of the geometric changes.

SIGNIFICANCE

These methods will enable researchers to more easily perform virtual-surgery-like deformations, computationally explore the impact of vascular shape on patient hemodynamics, and generate synthetic geometries for data-driven research.

Aneurysm sac shrinkage at 1 year after fenestrated-branched endovascular aortic repair of complex aortic aneurysms offers mid-term survival advantage

OBJECTIVES

To investigate the impact of 1-year changes in aneurysm sac diameter on patient survival after fenestrated-branched endovascular aortic repair (FB-EVAR) of complex abdominal aortic aneurysms or thoracoabdominal aortic aneurysms.

METHODS

We reviewed the clinical data of patients enrolled in a prospective nonrandomized study investigating FB-EVAR (2013-2022). Patients with sequential follow up computed tomography scans at baseline and 6 to 18 months after FB-EVAR were included in the analysis. Aneurysm sac diameter change was defined as the difference in maximum aortic diameter from baseline measurements obtained in centerline of flow. Patients were classified as those with sac shrinkage (≥5 mm) or failure to regress (<5 mm or expansion) according to sac diameter change. The primary end point was all-cause mortality. Secondary end points were aortic-related mortality (ARM), aortic aneurysm rupture (AAR), and aorta-related secondary intervention.

RESULTS

There were 549 patients treated by FB-EVAR. Of these, 463 patients (71% male, mean age, 74 ± 8 years) with sequential computed tomography imaging were investigated. Aneurysm extent was thoracoabdominal aortic aneurysms in 328 patients (71%) and abdominal aortic aneurysms in 135 (29%). Sac shrinkage occurred in 270 patients (58%) and failure to regress in 193 patients (42%), including 19 patients (4%) with sac expansion at 1 year. Patients from both groups had similar cardiovascular risk factors, except for younger age among patients with sac shrinkage (73 ± 8 years vs 75 ± 8 years; P < .001). The median follow-up was 38 months (interquartile range, 18-51 months). The 5-year survival estimate was 69% ± 4.1% for the sac shrinkage group and 46% ± 6.2% for the failure to regress group. Survival estimates adjusted for confounders (age, chronic pulmonary obstructive disease, chronic kidney disease, congestive heart failure, and aneurysm extent) revealed a higher hazard of late mortality in patients with failure to regress (adjusted hazard ratio, 1.72; 95% confidence interval, 1.18-2.52; P = .005). The 5-year cumulative incidences of ARM (1.1% vs 3.1%; P = .30), AAR (0.6% vs 2.6%; P = .20), and aorta-related secondary intervention (17.0% ± 2.8% vs 19.0% ± 3.8%) were both comparable between the groups.

CONCLUSIONS

Aneurysm sac shrinkage at 1 year is common after FB-EVAR and is associated with improved patient survival, whereas sac enlargement affects only a minority of patients. The low incidences of ARM and AAR indicate that failure to regress may serve as a surrogate marker for nonaortic-related death.

Comparison of Various Functional Assessment Tools to Identify Older Patients Undergoing Aortic Aneurysm Repair at Risk for Postoperative Complications

BACKGROUND

To estimate whether the benefits of aortic aneurysm repair will outweigh the risks, determining individual risks is essential. This single-center prospective cohort study aimed to compare the association of functional tools with postoperative complications in older patients undergoing aortic aneurysm repair.

METHODS

Ninety-eight patients (≥65 years) who underwent aortic aneurysm repair were included. Four functional tools were administered: the Montreal Cognitive Assessment (MoCA); the 4-Meter Walk Test (4-MWT); handgrip strength; and the Groningen Frailty Indicator (GFI). Primary outcome was the association between all tests and 30-day postoperative complications.

RESULTS

After adjusting for confounders, the odds ratio for MoCA was 1.39 (95% confidence interval [CI] 0.450; 3.157; P = 0.723), for 4-MWT 0.63 (95% CI 0.242; 1.650; P = 0.348), for GFI 1.82 (95% CI 0.783; 4.323, P = 0.162), and for weak handgrip strength 4.78 (95% CI 1.338; 17.096, P = 0.016).

CONCLUSIONS

Weak handgrip strength is significantly associated with the development of postoperative complications after aortic aneurysm repair. This study strengthens the idea that implementing a quick screening tool for risk assessment at the outpatient clinic, such as handgrip strength, identifies patients who may benefit from preoperative enhancement with help from, for example, Comprehensive Geriatric Assessment, eventually leading to better outcomes for this patient group.

Implications and late outcomes of type II endoleaks after endovascular aneurysm repair

OBJECTIVE

Type II endoleaks (T2ELs) are the most common cause of reintervention after endovascular aneurysm repair (EVAR). Although most resolve spontaneously, the long-term implications of T2ELs remain elusive. We aim to evaluate the impact of persistent and late T2ELs on clinical outcomes after EVAR.

METHODS

This was a single-institution retrospective review of patients who underwent EVAR for degenerative infrarenal abdominal aortic aneurysm between January 2010 and June 2022 with no type I (T1EL) or III (T3EL) endoleak seen at EVAR completion. Patients were categorized based on T2EL status. Group 1 included patients with never detected or transient T2ELs (detected at EVAR completion but not after). Group 2 encompassed persistent T2ELs (seen at EVAR completion and again during follow-up) and late T2ELs (detected for the first time at any point during follow-up). Time-to-event analysis was conducted using a time-dependent approach to T2EL status. Primary outcomes included freedom from sac enlargement (SE), aneurysm-related reinterventions, and overall survival.

RESULTS

A total of 803 patients met inclusion criteria. Group 1 included 418 patients (52%), of which 85% had no T2ELs and 15% had transient T2ELs. Group 2 had 385 patients; 23% had persistent T2ELs, and 77% developed a new T2EL. Patients in group 1 had a higher prevalence of smoking (88% vs 83%; P < .001), chronic obstructive pulmonary disease (33% vs 25%; P = .008), chronic kidney disease (13% vs 8%; P = .021), and a higher mean Society for Vascular Surgery score (7 vs 6 points; P = .049). No differences were found in aneurysm diameter or morphology. Mean follow-up was 5 years for the entire cohort. In Group 2, 58 patients (15%) underwent T2EL treatment, most commonly transarterial embolization. At 10 years after EVAR, Group 2 was associated with lower freedom from SE (P < .001) and abdominal aortic aneurysm-related reinterventions (P < .001) and comparable overall survival (P = .42). More T1ELs were detected during follow-up in Group 2 (6 [1%] vs 20 [5%]; P = .004), with 15 (75%) of these detected at a median of 3 years after the T2EL. No difference between groups was observed in explant (0.7% vs 2.1%; P = .130) or aneurysm rupture (0.5% vs 1.3%; P = .269) rates.

CONCLUSIONS

One-half of patients treated with infrarenal EVAR developed persistent/late T2ELs, which are associated with a higher risk of SE and reinterventions. No difference in overall survival or aneurysm rupture risk was seen at 10 years, based on T2EL status or T2EL intervention. A conservative approach to T2ELs may be appropriate for most patients with absent T1ELs or T3ELs.

LncRNA CARMN inhibits abdominal aortic aneurysm formation and vascular smooth muscle cell phenotypic transformation by interacting with SRF

Phenotypic transformation of vascular smooth muscle cells (VSMCs) plays a crucial role in abdominal aortic aneurysm (AAA) formation. CARMN, a highly conserved, VSMC-enriched long noncoding RNA (lncRNA), is integral in orchestrating various vascular pathologies by modulating the phenotypic dynamics of VSMCs. The influence of CARMN on AAA formation, particularly its mechanisms, remains enigmatic. Our research, employing single-cell and bulk RNA sequencing, has uncovered a significant suppression of CARMN in AAA specimens, which correlates strongly with the contractile function of VSMCs. This reduced expression of CARMN was consistent in both 7- and 14-day porcine pancreatic elastase (PPE)-induced mouse models of AAA and in human clinical cases. Functional analyses disclosed that the diminution of CARMN exacerbated PPE-precipitated AAA formation, whereas its augmentation conferred protection against such formation. Mechanistically, we found CARMN's capacity to bind with SRF, thereby amplifying its role in driving the transcription of VSMC marker genes. In addition, our findings indicate an enhancement in CAMRN transcription, facilitated by the binding of NRF2 to its promoter region. Our study indicated that CARMN plays a protective role in preventing AAA formation and restrains the phenotypic transformation of VSMC through its interaction with SRF. Additionally, we observed that the expression of CARMN is augmented by NRF2 binding to its promoter region. These findings suggest the potential of CARMN as a viable therapeutic target in the treatment of AAA.

Early Institutional Experience with One-Piece Bifurcated-Fenestrated Stentgraft in the Treatment of Abdominal Aortic Aneurysms

PURPOSE

To review the early experience of the use of a bifurcated-fenestrated endograft (Bif-FEVAR) to treat abdominal aortic aneurysms (AAA) in a high-volume aortic center.

METHODS

A retrospective single-center analysis was conducted between March 2019 and April 2021 including consecutive patients that underwent Bif-FEVAR. Only patients without a proper infrarenal neck and a distance <70 mm between the lowest target artery and the native or prosthetic aortic bifurcation were considered. All Bif-FEVAR custom-made devices were manufactured by Cook Medical (Inc., Bloomington, Indiana). Demographics, anatomical features, technical success, major adverse events, 30-day mortality, and survival according to Kaplan-Meier were analyzed according to Society for Vascular Surgery standards.

RESULTS

Overall, 10 patients (100% male with median age 78) were included. The median preoperative maximal aneurysm diameter was 68 mm [51-84]. Eight patients were treated for a proximal type I endoleak after endovascular aneurysm repair. A total of 36 fenestrations were planned. The median operative time was 144 min [127-168], with a median fluoro time of 40.5 min [34-54] and a median dose area product of 73 Gy cm2 [61-89]. Technical success rate was 100%. No patients experienced a major postoperative adverse event. Median follow-up time was 8 months [6-13].

CONCLUSION

Bif-FEVAR is technically feasible when there is a short distance below the lowest target artery and the aortic bifurcation, with favorable short-term results.

CLINICAL IMPACT

This study assessed the use of an innovative one-piece bifurcated fenestrated stent-graft as a primary procedure or in the treatment of proximal endoleak after standard infrarenal EVAR. We demonstrated these custom-made devices can be used safely with favorable short-term results. One-piece bifurcated fenestrated stent-grafts extend the indications of FEVAR for patients with an unusually short distance between the lowest renal artery and the aorto-iliac bifurcation or the diverter flow of a preexisting bifurcated infrarenal stent-graft.

Exploring the impact of gut microbiota on abdominal aortic aneurysm risk through a bidirectional Mendelian randomization analysis

OBJECTIVE

The abdominal aortic aneurysm (AAA) is associated with alterations in the composition of the gut microbiota; however, the precise causal relationship remains unclear. Elucidating this complex interplay could provide new insights into the pathogenesis of AAA.

METHODS

A bidirectional two-sample Mendelian randomization analysis was conducted using genome-wide association study summary data on the gut microbiota (n = 18,340) and AAA (n = 353,087). A total of 196 gut microbial taxa across taxonomic levels were examined for their potential causal effects on AAA risk. Conversely, the effect of AAA on these microbial taxa was also analyzed.

RESULTS

Nine microbial taxa were identified as having a causal influence on AAA risk. Specifically, increased risk were associated with genus Bilophila (odds ratio [OR], 1.359; P = .0119), genus Catenibacterium (OR, 1.348; P = .0058), genus family XIII AD3011 group (OR, 1.507; P = .004), genus Oxalobacter (OR, 1.157; P = .0449), and genus Prevotella 7 (OR, 1.194; P = .0306), whereas decreased risks were linked to class Lentisphaeria (OR, 0.829; P = .0361), order Victivallales (OR, 0.829; P = .0361), family Victivallaceae (OR, 0.814; P = .0057), and genus Anaerotruncus (OR, 0.773; P = .0497). Furthermore, AAA was found to influence the abundance of 14 microbial taxa across various taxonomic levels. Notably, bidirectional associations were observed with the class Lentisphaeria and the order Victivallales.

CONCLUSIONS

This study provides novel evidence for a reciprocal causal relationship between gut microbiota and AAA risk, thereby offering new insights into the pathogenesis of AAA. These findings also suggest promising avenues for microbiome-based therapeutic interventions.

The impact of dyslipidemia on prognosis of patients after endovascular abdominal aortic aneurysm repair

Introduction

Dyslipidemia is common in patients with abdominal aortic aneurysm (AAA). However, there is insufficient research on the impact of dyslipidemia on the postoperative outcomes of patients with AAA after endovascular aortic aneurysm repair (EVAR). This study aimed to determine the impact of dyslipidemia on the prognosis of patients with AAA treated with EVAR.

Method

We retrospectively reviewed patients with AAA who underwent EVAR at our hospital between 2010 and 2020. The baseline characteristics and prognoses of patients in the dyslipidemia and non-dyslipidemia groups were analyzed.

Results

A total of 641 patients were included; the prevalence of dyslipidemia in patients with AAA was 42.3% (271/641), and the mean follow-up time was 63.37 ± 26.49 months. The prevalence of diabetes (10.0% vs. 15.1%, P = 0.050), peripheral arterial disease (17.3% vs. 25.8%, P = 0.018), and chronic kidney disease (3.0% vs. 6.3%, P = 0.043) was higher in the dyslipidemia group. The three-year all-cause mortality rate after EVAR was 9.98% (64/641), and there was no difference in the incidence of all-cause mortality (10.27% vs. 9.59%, P = 0.778) between the two groups. A total of 36 (5.62%) major adverse cardiovascular and cerebrovascular events (MACCEs) were observed within 3 years and were more common in patients with dyslipidemia (2.97% vs. 9.59%, P < 0.001). The incidence of stent-related complications in all patients was 19.97% (128/641), and there was no difference in the incidence of stent-related complications between the two groups (22.16% vs. 16.97%, P = 0.105); however, the incidence of type I endoleak in the dyslipidemia group was lower than that in the non-dyslipidemia group (9.19% vs. 4.06%, P = 0.012). Cox-regression analysis showed that high level of high-density lipoprotein cholesterol (HDL-C) was the protective factor (HR, 0.203, 95% CI, 0.067-0.616, P = 0.005) for MACCES, but it was the risk factor for type I endoleak (HR, 2.317, 95% CI, 1.202-4.466, P = 0.012).

Conclusion

Dyslipidemia did not affect the mortality of patients with AAA who underwent EVAR; however, it may increase the incidence of MACCEs. Dyslipidemia may decrease the incidence of type I endoleaks after EVAR; however, further studies are warranted. We should strengthen the postoperative management of patients with dyslipidemia, prevent the occurrence of MACCEs.

Revealing PPP1R12B and COL1A1 as piRNA pathway genes contributing to abdominal aortic aneurysm through integrated analysis and experimental validation

BACKGROUND

Abdominal aortic aneurysm (AAA) is a permanent dilation of the abdominal aorta, with a high mortality rate when rupturing. Although lots of piRNA pathway genes (piRPGs) have recently been linked to both neoplastic and non-neoplastic illnesses, their role in AAA is still unknown. Utilizing integrative bioinformatics methods, this research discovered piRPGs as biomarkers for AAA and explore possible molecular mechanisms.

METHODS

The datasets were obtained from the Gene Expression Omnibus and piRPGs were identified from the Genecards database. The "limma" and "clusterProfiler" R-packages were used to discover differentially expressed genes and perform enrichment analysis, respectively. Hub piRPGs were further filtered using least absolute shrinkage and selection operator regression, random forests, as well as receiver operating characteristic curve. Additionally, multi-factor logistic regression (MLR), extreme gradient boosting (XGboost), and artificial neural network (ANN) were employed to construct prediction models. The relationship between hub piRPGs and immune infiltrating cells and sgGSEA were further studied. The expression of hub piRPGs was verified by qRT-PCR, immunohistochemistry, and western blotting in AAA and normal vascular tissues and analyzed by scRNA-seq in mouse AAA model. SRAMP and cMAP database were utilized for the prediction of N6-methyladenosine (m6A) targets therapeutic drug.

RESULTS

34 differentially expressed piRPGs were identified in AAA and enriched in pathways of immune regulation and gene silence. Three piRPGs (PPP1R12B, LRP10, and COL1A1) were further screened as diagnostic genes and used to construct prediction model. Compared with MLR and ANN, Xgboost showed better predictive ability, and PPP1R12B might have the ability to distinguish small and large AAA. Furthermore, the expression levels of PPP1R12B and COL1A1 were consistent with the results of bioinformatics analysis, and PPP1R12B showed a downward trend that may be related to m6A.

CONCLUSION

The results suggest that piRPGs might serve a significant role in AAA. PPP1R12B, COL1A1, and LRP10 had potential as diagnostic-specific biomarkers for AAA and performed better in XGboost model. The expression and localization of PPP1R12B and COL1A1 were experimentally verified. Besides, downregulation of PPP1R12B caused by m6A might contribute to the formation of AAA.

Pathogenesis-Guided Rational Engineering of Nanotherapies for the Targeted Treatment of Abdominal Aortic Aneurysm by Inhibiting Neutrophilic Inflammation

Abdominal aortic aneurysm (AAA) remains a fatal disease in the elderly. Currently, no drugs can be clinically used for AAA therapy. Considering the pivotal role of neutrophils in the pathogenesis of AAA, herein we propose the targeted therapy of AAA by site-specifically regulating neutrophilic inflammation. Based on a luminol-conjugated α-cyclodextrin material (LaCD), intrinsically anti-inflammatory nanoparticles (NPs) were engineered by simple nanoprecipitation, which were examined as a nanotherapy (defined as LaCD NP). After efficient accumulation in the aneurysmal aorta and localization in pathologically relevant inflammatory cells in rats with CaCl2-induced AAA, LaCD NP significantly alleviated AAA progression, as implicated by the decreased aortic expansion, suppressed elastin degradation, inhibited calcification, and improved structural integrity of the abdominal aorta. By functionalizing LaCD NP with alendronate, a calcification-targeting moiety, the in vivo aneurysmal targeting capability of LaCD NP was considerably enhanced, thereby affording significantly potentiated therapeutic outcomes in AAA rats. Mechanistically, LaCD NP can effectively inhibit neutrophil-mediated inflammatory responses in the aneurysmal aorta. Particularly, LaCD NP potently attenuated the formation of neutrophil extracellular traps (NETs), thereby suppressing NETs-mediated pro-inflammatory events and NETosis-associated negative effects responsible for AAA progression. Consequently, we demonstrated the effectiveness and underlying mechanisms of anti-NETosis nanotherapies for the targeted treatment of AAA. Our findings provide promising insights into discovering precision therapies for AAA and other inflammatory vascular diseases.

The future for the therapeutics of abdominal aortic aneurysm: engineered nanoparticles drug delivery for abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a severe cardiovascular disease with a high mortality rate. Several screening and diagnostic methods have been developed for AAA early diagnosis. Open surgery and endovascular aortic repair (EVAR) are clinically available for patients who meet the indications for surgery. However, for non-surgical patients, limited drugs exist to inhibit or reverse the progression of aneurysms due to the complex pathogenesis and biological structure of AAA, failing to accumulate precisely on the lesion to achieve sufficient concentrations. The recently developed nanotechnology offers a new strategy to address this problem by developing drug-carrying nanoparticles with enhanced water solubility and targeting capacity, prolonged duration, and reduced side effects. Despite the rising popularity, limited literature is available to highlight the progression of the field. Herein, in this review, we first discuss the pathogenesis of AAA, the methods of diagnosis and treatment that have been applied clinically, followed by the review of research progressions of constructing different drug-loaded nanoparticles for AAA treatment using engineered nanoparticles. In addition, the feasibility of extracellular vesicles (EVs) and EVs-based nanotechnology for AAA treatment in recent years are highlighted, together with the future perspective. We hope this review will provide a clear picture for the scientists and clinicians to find a new solution for AAA clinical management.

Current Imaging Strategies in Patients with Abdominal Aortic Aneurysms

BACKGROUND

 An abdominal aortic aneurysm (AAA) is defined as a localized dilatation of the abdominal aorta of ≥ 3 cm. With a prevalence of 4-8 %, AAA is one of the most common vascular diseases in Western society. Radiological imaging is an elementary component in the diagnosis, monitoring, and treatment planning of AAA patients.

METHOD

 This is a narrative review article on preoperative imaging strategies of AAA, incorporating expert opinions based on the current literature and standard-of-care practices from our own center. Examples are provided to illustrate clinical cases from our institution.

RESULTS AND CONCLUSION

 Radiological imaging plays a pivotal role in the initial diagnosis and monitoring of patients with AAA. Ultrasound is the mainstay imaging modality for AAA screening and surveillance. Contrast-enhanced CT angiography is currently considered the gold standard for preoperative imaging and image-based treatment planning in AAA repair. New non-contrast MR angiography techniques are robustly applicable and allow precise determination of aortic diameters, which is of critical importance, particularly with regard to current diameter-based surgical treatment guidelines. 3D imaging with multiplanar reformation and automatic centerline positioning enables more accurate assessment of the maximum aortic diameter. Modern imaging techniques such as 4D flow MRI have the potential to further improve individualized risk stratification in patients with AAA.

KEY POINTS

  · Ultrasound is the mainstay imaging modality for AAA screening and monitoring. · Contrast-enhanced CT angiography is the gold standard for preoperative imaging in AAA repair. · Non-contrast MR angiography allows for accurate monitoring of aortic diameters in AAA patients. · Measurement of aortic diameters is more accurate with 3D-CT/MRI compared to ultrasound. · Research seeks new quantitative imaging biomarkers for AAA risk stratification, e. g., using 4D flow MRI.

Changes in treatment patterns of thoracoabdominal aortic aneurysms in the United States

Background

The introduction of endovascular repair provides an alternative to traditional open repair of thoracoabdominal aortic aneurysms (TAAA). Its utility is not well defined, however. Using a national database, we studied the treatment patterns and outcomes of TAAA to gain insight into its contemporary surgical practice in the United States.

Methods

Records of TAAA patients who received endovascular and open repair were retrieved from the 2002 to 2018 National Inpatient Sample database. Each cohort was stratified into 4 age groups: ≤50, 51 to 60, 61 to 70, and >70 years. Patient characteristics and in-hospital outcomes were compared between the 2 repair modalities. Temporal trends were investigated.

Results

Endovascular repair use increased steadily, whereas open repair volume remained stable until 2012, before declining by 50% by 2018. This appears to be associated with a declining number of open repairs in patients age >60 years. Patients who underwent endovascular repair were older and had a higher Charlson Comorbidity Index (mean, 2.8 ± 1.7 vs 2.5 ± 1.5; P < .001) but lower in-hospital mortality (mean, 8.9% vs 17.1%; P < .001), shorter length of stay (mean, 10.1 ± 12.2 days vs 17.1 ± 17.4 days; P < .001), and fewer postoperative complications. A difference in mortality between open and endovascular repair was observed for patients age >60 years but not for patients age ≤60 years.

Conclusions

There has been a shift in the treatment of TAAA in the United States from open repair-dominant to endovascular repair-dominant. It has increased surgical access for older and more comorbid patients and has led to a decline in the use of open repair while lowering in-hospital mortality.

Role of Common Antihypertensives in the Growth of Abdominal Aortic Aneurysm at the Presurgical Stage

Background: Whether drug therapy slows the growth of abdominal aortic aneurysms (AAAs) in the Japanese population remains unknown. Methods and Results: In a multicenter prospective open-label study, patients with AAA at the presurgical stage (mean [±SD] AAA diameter 3.27±0.58 cm) were randomly assigned to treatment with candesartan (CAN; n=67) or amlodipine (AML; n=64) considering confounding factors (statin use, smoking, age, sex, renal function), with effects of blood pressure control minimized setting a target control level. The primary endpoint was percentage change in AAA diameter over 24 months. Secondary endpoints were changes in circulating biomarkers (high-sensitivity C-reactive protein [hs-CRP], malondialdehyde-low-density lipoprotein, tissue-specific inhibitor of metalloproteinase-1, matrix metalloproteinase [MMP] 2, MMP9, transforming growth factor-β1, plasma renin activity [PRA], angiotensin II, aldosterone). At 24 months, percentage changes in AAA diameter were comparable between the CAN and AML groups (8.4% [95% CI 6.23-10.59%] and 6.5% [95% CI 3.65-9.43%], respectively; P=0.23]. In subanalyses, AML attenuated AAA growth in patients with comorbid chronic kidney disease (CKD; P=0.04) or systolic blood pressure (SBP) <130 mmHg (P=0.003). AML exhibited a definite trend for slowing AAA growth exclusively in never-smokers (P=0.06). Among circulating surrogate candidates for AAA growth, PRA (P=0.02) and hs-CRP (P=0.001) were lower in the AML group. Conclusions: AML may prevent AAA growth in patients with CKD or lower SBP, associated with a decline in PRA and circulating hs-CRP.

Association between the non-HDL-cholesterol to HDL- cholesterol ratio and abdominal aortic aneurysm from a Chinese screening program

BACKGROUND

Abdominal aortic aneurysms (AAAs) can result in high mortality upon rupture but are usually undiagnosed because of the absence of symptoms in the early stage. Ultrasound screening is regarded as an impactful way to prevent the AAA-related death but cannot be performed efficiently; therefore, a target population, especially in Asia, for this procedure is lacking. Additionally, although dyslipidaemia and atherosclerosis are associated with AAA. However, it remains undetermined whether the non-high-density lipoprotein-cholesterol to high-density lipoprotein-cholesterol ratio (NHHR) is associated with AAA. Therefore, this study was aimed at examining whether NHHR is associated with AAA.

METHOD

A total of 9559 participants who underwent AAA screening at Guangdong Provincial People's Hospital and through screening in two communities in Dongguan, from June 2019 to June 2021 joined in this screening program. The diagnosis of AAA was confirmed by the ultrasound examination of the abdominal aorta rather than any known or suspected AAA. Clinical and laboratory data of participants were collected. The participants were separated into a normal group and an AAA group according to the abdominal aortic status. To eliminate confounding factors, a propensity score matching (PSM) approach was utilized. The independent relationship between NHHR and AAA was assessed through the utilization of multivariable logistic regression analysis. In addition, internal consistency was evaluated through subgroup analysis, which controlled for significant risk factors.

RESULTS

Of all the participants, 219 (2.29%) participants were diagnosed with AAA. A significant elevation in NHHR was identified in the AAA group when contrasted with that in the normal group (P < 0.001). As demonstrated by the results of the multivariable logistic regression analysis, AAA was independently associated with NHHR before (odds ratio [OR], 1.440, P < 0.001) and after PSM (OR, 1.515, P < 0.001). Significant extension was observed in the areas under the receiver operating characteristic curves (AUROCs) of NHHR compared to those of single lipid parameters before and after PSM. An accordant association between NHHR and AAA in different subgroups was demonstrated by subgroup analysis.

CONCLUSION

In the Chinese population, there is an independent association between NHHR and AAA. NHHR might be propitious to distinguish individuals with high risk of AAA.

Changes in renal-mesenteric duplex ultrasound velocities after fenestrated and branched endovascular aortic aneurysm repair

OBJECTIVE

Stenting of renal and mesenteric vessels may result in changes in velocity measurements due to arterial compliance, potentially giving rise to confusion about the presence of stenosis during follow-up. The aim of our study was to compare preoperative and postoperative changes in peak systolic velocity (PSV, cm/s) after placement of the celiac axis (CA), superior mesenteric artery (SMA) and renal artery (RAs) bridging stent grafts during fenestrated-branched endovascular aortic repair (FB-EVAR) for treatment of complex abdominal aortic aneurysms (AAA) and thoracoabdominal aortic aneurysms.

METHODS

Patients were enrolled in a prospective, nonrandomized single-center study to evaluate FB-EVAR for treatment of complex AAA and thoracoabdominal aortic aneurysms between 2013 and 2020. Duplex ultrasound examination of renal-mesenteric vessels were obtained prospectively preoperatively and at 6 to 8 weeks after the procedure. Duplex ultrasound examination was performed by a single vascular laboratory team using a predefined protocol including PSV measurements obtained with <60° angles. All renal-mesenteric vessels incorporated by bridging stent grafts using fenestrations or directional branches were analyzed. Target vessels with significant stenosis in the preoperative exam were excluded from the analysis. The end point was variations in PSV poststent placement at the origin, proximal, and mid segments of the target vessels for fenestrations and branches.

RESULTS

There were 419 patients (292 male; mean age, 74 ± 8 years) treated by FB-EVAR with 1411 renal-mesenteric targeted vessels, including 260 CAs, 409 SMAs, and 742 RAs. No significant variances in the mean PSVs of all segments of the CA, SMA, and RAs at 6 to 8 weeks after surgery were found as compared with the preoperative values (CA, 135 cm/s vs 141 cm/s [P = .06]; SMA, 128 cm/s vs 125 cm/s [P = .62]; RAs, 90 cm/s vs 83 cm/s [P = .65]). Compared with baseline preoperative values, the PSV of the targeted vessels showed no significant differences in the origin and proximal segment of all vessels. However, the PSV increased significantly in the mid segment of all target vessels after stent placement.

CONCLUSIONS

Stent placement in nonstenotic renal and mesenteric vessels during FB-EVAR is not associated with a significant increase in PSVs at the origin and proximal segments of the target vessels. Although there is a modest but significant increase in velocity measurements in the mid segment of the stented vessel, this difference is not clinically significant. Furthermore, PSVs in stented renal and mesenteric arteries were well below the threshold for significant stenosis in native vessels. These values provide a baseline or benchmark for expected PSVs after renal-mesenteric stenting during FB-EVAR.

Early Progression of Abdominal Aortic Aneurysm is Decelerated by Improved Endothelial Barrier Function via ALDH2-LIN28B-ELK3 Signaling

The involvement of endothelial barrier function in abdominal aortic aneurysm (AAA) and its upstream regulators remains unknown. Single-cell RNA sequencing shows that disrupted endothelial focal junction is an early (3 days) and persistent (28 days) event during Angiotensin II (Ang II)-induced AAA progression. Consistently, mRNA sequencing on human aortic dissection tissues confirmed downregulated expression of endothelial barrier-related genes. Aldehyde dehydrogenase 2 (ALDH2), a negative regulator of AAA, is found to be upregulated in the intimal media of AAA samples, leading to testing its role in early-stage AAA. ALDH2 knockdown/knockout specifically in endothelial cells (ECs) significantly increases expression of EC barrier markers related to focal adhesion and tight junction, restores endothelial barrier integrity, and suppresses early aortic dilation of AAA (7 and 14 days post-Ang II). Mechanically, ELK3 acts as an ALDH2 downstream regulator for endothelial barrier function preservation. At the molecular level, ALDH2 directly binds to LIN28B, a regulator of ELK3 mRNA stability, hindering LIN28B binding to ELK3 mRNA, thereby depressing ELK3 expression and impairing endothelial barrier function. Therefore, preserving vascular endothelial barrier integrity via ALDH2-specific knockdown in ECs holds therapeutic potential in the early management of AAAs.

A pilot study to evaluate a novel localized treatment to stabilize small- to medium-sized infrarenal abdominal aortic aneurysms

OBJECTIVE

There is no proven therapy to reduce growth rates of small- to medium-sized abdominal aortic aneurysms (AAAs). Ex vivo and animal studies have demonstrated that a novel stabilizing agent, 1,2,3,4,6-pentagalloyl glucose (PGG), delivered locally to the aneurysm sac, can bind to elastin and collagen to re-establish strength and resist enzymatic degradation. We aimed to demonstrate that a one-time administration of PGG solution to the aneurysm wall is safe and potentially effective to slow the growth of small- to medium-sized AAAs.

METHODS

Patients with small- to medium-sized infrarenal AAAs (maximum diameter <5.5 cm) were recruited. Via transfemoral access, a 14F or 16F dual-balloon delivery catheter was introduced into the aneurysm sac. A single, 3-minute, localized endoluminal infusion of PGG was delivered via a 'weeping' balloon to the aneurysm wall. Independent core laboratory measurements of maximum aneurysm sac diameter and sac volume measurements based on computed tomography angiography (CTA) were used for assessments at 1, 6, 12, 24, and 36 months. The primary endpoints were technical success and safety (major adverse events at 30 days). The secondary endpoint was growth stabilization, defined as freedom from aneurysm sac enlargement (diameter increase >5 mm per year or volume increase of >10% per year).

RESULTS

Twenty patients (19 male) were enrolled at five centers from May 2019 to June 2022 (mean age, 67.8 years; range, 50-87 years). All procedures were technically successful. The safety profile was consistent with standard interventional procedures. Four patients demonstrated transient elevations of liver enzymes levels that returned to normal by 30 days with no clinical symptoms. Through November 2022, follow-up CTA data is available on the first 11 patients. The average changes in maximum aneurysm diameter from baseline to 6, 12, 24, and 36 months were 0.2 mm, 1.1 mm, 1.2 mm, and 0.8 mm, respectively, and the average changes in volume were 2.0%, 9.6%, 18.1%, and 11.6%, respectively. At 12 months, none of the aneurysms showed growth >5.0 mm, and three had volume growth >10%.

CONCLUSIONS

The early results of this first-in-human, small cohort study demonstrated that a single, localized PGG administration to patients with small- to medium-sized infrarenal AAAs is safe. Longer term follow-up on all 20 treated patients is needed to better assess the potential impact on aneurysm growth.

Assessing Abdominal Aortic Aneurysm Progression by Using Perivascular Adipose Tissue Attenuation on Computed Tomography Angiography

OBJECTIVE

Recent studies have highlighted the active and potential role of perivascular adipose tissue (PVAT) in atherosclerosis and aneurysm progression, respectively. This study explored the link between PVAT attenuation and abdominal aortic aneurysm (AAA) progression using computed tomography angiography (CTA).

MATERIALS AND METHODS

This multicenter retrospective study analyzed patients with AAA who underwent CTA at baseline and follow-up between March 2015 and July 2022. The following parameters were obtained: maximum diameter and total volume of the AAA, presence or absence of intraluminal thrombus (ILT), maximum diameter and volume of the ILT, and PVAT attenuation of the aortic aneurysm at baseline CTA. PVAT attenuation was divided into high (> -73.4 Hounsfield units [HU]) and low (≤ -73.4 HU). Patients who had or did not have AAA progression during the follow-up, defined as an increase in the aneurysm volume > 10 mL from baseline, were identified. Kaplan-Meier and multivariable Cox regression analyses were used to investigate the association between PVAT attenuation and AAA progression.

RESULTS

Our study included 167 participants (148 males; median age: 70.0 years; interquartile range: 63.0-76.0 years), of which 145 (86.8%) were diagnosed with AAA accompanied by ILT. Over a median period of 11.3 months (range: 6.0-85.0 months), AAA progression was observed in 67 patients (40.1%). Multivariable Cox regression analysis indicated that high baseline PVAT attenuation (adjusted hazard ratio [aHR] = 2.23; 95% confidence interval [CI], 1.16-4.32; P = 0.017) was independently associated with AAA progression. This association was demonstrated within the patients of AAA with ILT subcohort, where a high baseline PVAT attenuation (aHR = 2.23; 95% CI, 1.08-4.60; P = 0.030) was consistently independently associated with AAA progression.

CONCLUSION

Elevated PVAT attenuation is independently associated with AAA progression, including patients of AAA with ILT, suggesting the potential of PVAT attenuation as a predictive imaging marker for AAA expansion.

The circular RNA Ataxia Telangiectasia Mutated regulates oxidative stress in smooth muscle cells in expanding abdominal aortic aneurysms

An abdominal aortic aneurysm (AAA) is a pathological widening of the aortic wall characterized by loss of smooth muscle cells (SMCs), extracellular matrix degradation, and local inflammation. This condition is often asymptomatic until rupture occurs, leading to high morbidity and mortality rates. Diagnosis is mostly accidental and the only currently available treatment option remains surgical intervention. Circular RNAs (circRNAs) represent a novel class of regulatory non-coding RNAs that originate from backsplicing. Their highly stable loop structure, combined with a remarkable enrichment in body fluids, make circRNAs promising disease biomarkers. We investigated the contribution of circRNAs to AAA pathogenesis and their potential application to improve AAA diagnostics. Gene expression analysis revealed the presence of deregulated circular transcripts stemming from AAA-relevant gene loci. Among these, the circRNA to the Ataxia Telangiectasia Mutated gene (cATM) was upregulated in human AAA specimens, in AAA-derived SMCs, and serum samples collected from aneurysm patients. In primary aortic SMCs, cATM increased upon angiotensin II and doxorubicin stimulation, while its silencing triggered apoptosis. Higher cATM levels made AAA-derived SMCs less vulnerable to oxidative stress, compared with control SMCs. These data suggest that cATM contributes to elicit an adaptive oxidative-stress response in SMCs and provides a reliable AAA disease signature.

Management of Endoleaks After Elective Infrarenal Aortic Endovascular Aneurysm Repair: A Review

Importance

Endovascular aneurysm repair (EVAR) is the dominant treatment strategy for abdominal aortic aneurysms, encompassing 80% of all repairs in the United States. Endoleaks are ubiquitous and affect 30% of patients treated by EVAR, potentially leading to sac enlargement and increased risk of rupture. The care of EVAR patients requires long-term surveillance by a multidisciplinary team. Accordingly, physicians should be familiar with the fundamentals of endoleak management to achieve optimal outcomes, including timely referral for remediation or providing counseling and reassurance when needed.

Observations

PubMed and the Cochrane database were searched for articles published between January 2002 and December 2022 in English, addressing epidemiology, diagnosis, and management of endoleaks after EVAR. Endoleaks can be detected intraoperatively or years later, making lifelong surveillance mandatory. Type I and III have the highest risk of rupture (7.5% at 2 years and 8.9% at 1 year, respectively) and should be treated when identified. Intervention should be considered for other types of endoleak when associated with aneurysm sac growth larger than 5 mm based on current guidelines. Type II endoleaks are the most common, accounting for 50% of all endoleaks. Up to 90% of type II endoleaks resolve spontaneously or are not associated with sac enlargement, requiring only observation. Although the risk of rupture is less than 1%, cases that require reintervention are challenging. Recurrence is common despite endovascular treatment, and rupture can occur without evidence of sac growth. Type IV endoleaks and endotension are uncommon, are typically benign, and primarily should be observed.

Conclusions and Relevance

Endoleak management depends on the type and presence of sac expansion. Type I and III endoleaks require intervention. Type II endoleaks should be observed and treated selectively in patients with significant sac expansion. Since endoleaks can appear any time after EVAR, at least 1 contrast-enhanced computed tomographic angiogram or duplex ultrasound by an experienced laboratory is recommended every 5 years.

Novel pharmacological approaches in abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a severe vascular disease and a major public health issue with an unmet medical need for therapy. This disease is featured by a progressive dilation of the abdominal aorta, boosted by atherosclerosis, ageing, and smoking as major risk factors. Aneurysm growth increases the risk of aortic rupture, a life-threatening emergency with high mortality rates. Despite the increasing progress in our knowledge about the etiopathology of AAA, an effective pharmacological treatment against this disorder remains elusive and surgical repair is still the unique available therapeutic approach for high-risk patients. Meanwhile, there is no medical alternative for patients with small aneurysms but close surveillance. Clinical trials assessing the efficacy of antihypertensive agents, statins, doxycycline, or anti-platelet drugs, among others, failed to demonstrate a clear benefit limiting AAA growth, while data from ongoing clinical trials addressing the benefit of metformin on aneurysm progression are eagerly awaited. Recent preclinical studies have postulated new therapeutic targets and pharmacological strategies paving the way for the implementation of future clinical studies exploring these novel therapeutic strategies. This review summarises some of the most relevant clinical and preclinical studies in search of new therapeutic approaches for AAA.

Prevalence of risk factors associated with rupture of abdominal aortic aneurysm (AAA): a single center retrospective study

BACKGROUND

Abdominal aortic aneurysm (AAA) is a severe cardiovascular disease. The mortality rate for an AAA rupture is very high. Understanding the risk factors for AAA rupture would help AAA management, but little is known about these risk factors in the Chinese population.

METHODS

This retrospective study included patients that were diagnosed with AAA during the last 5 years in a large national hospital in southern China. AAA patients were divided into a rupture and non-rupture group. Clinical data were extracted from the hospital medical record system. Clinical features were compared between the rupture and non-rupture groups. The associations between potential risk factors and rupture risk were evaluated using a multivariate logistic regression analysis.

RESULTS

A total of 337 AAA patients were included for analysis in the present study. AAA diameter was significantly larger, and high-sensitivity C-reactive protein (hs-CRP) and serum creatinine levels were both significantly higher in AAA rupture patients. High-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) levels were significantly lower in AAA rupture patients. After adjustment, the multivariate logistic analysis found that AAA diameter and hs-CRP were independently positively associated with AAA rupture, and HDL-C level was adversely associated with AAA rupture.

CONCLUSIONS

Our data suggests that larger AAA diameter and higher hs-CRP level are associated with a higher risk of AAA rupture, and higher HDL-C level is associated with a lower risk of AAA rupture. The results of this study may be helpful for the management of AAA patients in southern China.

Asymptomatic Fusiform Aortic Aneurysms in a 37-Year-Old Male: A Case Report

Abdominal aortic aneurysm (AAA) is mostly present in patients aged ≥65 years. Here, we present an unusual case of a 37-year-old male with a pair of asymptomatic, fusiform abdominal aortic aneurysms above and below the origin of the renal arteries. The patient was diagnosed with AAA in 2016 and had undergone yearly follow-ups since then. He had no major risk factors for AAA other than hypertension, which was managed with medication, and had only a brief history of smoking. He was also negative for all genetic and connective tissue defects. His aneurysms progressed slowly, with proximal and distal aneurysms currently measuring 3.9 cm and 4.5 cm, respectively. The patient was asymptomatic and was closely examined for further management.

Management of Abdominal Aortic Aneurysm With Concomitant Acute Cholecystitis in the Era of Endovascular Surgery

The incidence of symptomatic acute cholecystitis with large (greater than 5.5 cm) abdominal aortic aneurysm is an uncommon occurrence. Guidelines on concomitant repair in this setting remain elusive, particularly in the era of endovascular repair. We present a case of acute cholecystitis in a 79-year-old female presenting to a local rural emergency room with abdominal pain and known abdominal aortic aneurysm (AAA). Abdominal computed tomography (CT) revealed a 5.5 cm infrarenal abdominal aortic aneurysm, significantly greater in size compared to previous imaging, as well as a distended gallbladder with mild wall thickening and cholelithiasis concerning for acute cholecystitis. The two conditions were found to be unrelated to each other, but concerns were raised on appropriate timing of care. Following diagnosis, the patient underwent concomitant treatment of acute cholecystitis and large abdominal aortic aneurysm with laparoscopic and endovascular techniques, respectively. In this report, we take the opportunity to discuss the treatment of patients with AAA and concomitant symptomatic acute cholecystitis.

Characterizing the frequency and indications for repair of abdominal aortic aneurysms with diameters smaller than recommended by societal guidelines

OBJECTIVE

While the Society for Vascular Surgery recommends repair of abdominal aortic aneurysms (AAA) at ≥5.5 cm in men and ≥5.0 cm in women, AAA repair below these thresholds has been well documented. There are clear indications for repair other than these strict size criteria, but the expected proportion of such repairs in one's practice has not been studied. We sought to characterize the indications for repairs of aneurysms below diameter recommendations at a single academic center. Using the assumption that this real-world experience would approximate that of other practices, we then used national data to extrapolate these findings.

METHODS

A single-center retrospective review was conducted of all elective open (oAAA) and endovascular (EVAR) AAA repairs (2010-20) to assess the incidence of and indications for repair of aneurysms below diameter recommendations (defined as <5.5cm in men and <5.0cm in women). Reasons for these repairs were defined as: 1) iliac aneurysm, 2) saccular morphology, 3) rapid expansion, 4) patient anxiety, 5) distal embolization, 6) other, and 7) no documented reason. The Vascular Quality Initiative (VQI) was queried for all asymptomatic oAAA and EVAR (2010-20) and repairs below diameter recommendations were identified. Findings from the single-center analysis were applied to the VQI cohort to extrapolate estimates of reasons for repairs done nationally. In-hospital mortality and major adverse cardiac events (MACE) were compared between those below size recommendations and those meeting size recommendations.

RESULTS

Of 456 elective AAA repairs at our center, 147 (32%) were below size recommendations. This was more common for EVAR (35% vs 28%). Reasons were: not documented (41%), iliac aneurysm (23%), saccular (10%), rapid expansion (10%), patient anxiety (7%), other (6%), and distal embolism (3%). Of 44,820 elective AAA repairs in VQI, 17,057 (38%) were below size recommendations (40% EVAR, 26% oAAA). Patients who were repaired below size recommendations had lower in-hospital death (oAAA: 2.4% vs 4.6% p<0.0001; EVAR: 0.3% vs 0.8% p<0.0001). When single-center findings were applied to the VQI dataset, an estimated 10,064 repairs were performed nationally for acceptable indications other than size criteria. Conversely, there may have been 6993 repairs (with an associated 35 deaths) performed without documented indication.

CONCLUSION

Repairs for AAA below recommended diameter guidelines account for approximately one third of all elective AAA procedures in both VQI and our single-center experience. Assuming our practice is typical, nearly 60% of repairs below size recommendations meet criteria for other clear reasons. The remaining 40% lack a documented reason, meaning 13% of all elective AAA repairs were done for aneurysms below size recommendations without an acceptable indication. As awareness of overuse/underuse is heightened, these data help estimate the expected proportion of repairs for less common pathologies. They also provide a potential baseline data point for efforts at reducing overuse.

The mechanism and therapy of aortic aneurysms

Aortic aneurysm is a chronic aortic disease affected by many factors. Although it is generally asymptomatic, it poses a significant threat to human life due to a high risk of rupture. Because of its strong concealment, it is difficult to diagnose the disease in the early stage. At present, there are no effective drugs for the treatment of aneurysms. Surgical intervention and endovascular treatment are the only therapies. Although current studies have discovered that inflammatory responses as well as the production and activation of various proteases promote aortic aneurysm, the specific mechanisms remain unclear. Researchers are further exploring the pathogenesis of aneurysms to find new targets for diagnosis and treatment. To better understand aortic aneurysm, this review elaborates on the discovery history of aortic aneurysm, main classification and clinical manifestations, related molecular mechanisms, clinical cohort studies and animal models, with the ultimate goal of providing insights into the treatment of this devastating disease. The underlying problem with aneurysm disease is weakening of the aortic wall, leading to progressive dilation. If not treated in time, the aortic aneurysm eventually ruptures. An aortic aneurysm is a local enlargement of an artery caused by a weakening of the aortic wall. The disease is usually asymptomatic but leads to high mortality due to the risk of artery rupture.

Bioinformatics-based identification of lipid- and immune-related biomarkers in abdominal aortic aneurysms

Background

Abdominal aortic aneurysm (AAA) manifest as a natural inflammatory process with permanent dilation and terminal rupture. Nevertheless, the pathogenesis of AAA remains a mystery, and treatment is still controversial. Lipid metabolism and immune system are involved in AAA progression, which has been well documented. However, lipid- and immune-related (LIR) biomarkers need to be further elucidated.

Methods

The AAA-related datasets were retrieved from the GEO database, and the datasets were analyzed for differential gene expression by NetworkAnalyst. GO and KEGG pathway enrichment analysis of differentially expressed mRNA (DE-mRNA) was performed using Metscape, and LIR DE-mRNA was further screened. AAA rat model was constructed using porcine pancreatic elastase to verify the differential expression of LIR DE-mRNA.

Results

The GSE47472 and GSE57691 datasets respectively identified 614 (containing 381 down-regulated and 233 up-regulated DE-mRNAs) and 384 (containing 218 down-regulated and 164 up-regulated DE-mRNAs) DE-mRNAs. Intersection and union of DE-mRNAs were 13 and 983, respectively. The main terms involved in the union of DE-mRNAs included "immune system process", "metabolic process", "Chemokine signaling pathway", "hematopoietic cell lineage" and "Cholesterol metabolism". In vivo experiments revealed that LIR DE-mRNAs of PDIA3, TYROBP, and HSPA1A were significantly low expression in AAA abdominal aortic tissues, and HCK and SERPINE1 were significantly high expression, which is consistent with the bioinformatics analysis.

Conclusions

PDIA3, TYROBP, HSPA1A, HCK and SERPINE1 may serve as LIR biomarkers of AAA, which provides new insights and theoretical guidance for the future treatment, early prevention and progression of AAA.

Pharmacologic inhibition by spironolactone attenuates experimental abdominal aortic aneurysms

Background

Abdominal aortic aneurysms (AAA) are characterized by vascular inflammation and remodeling that can lead to aortic rupture resulting in significant mortality. Pannexin-1 channels on endothelial cells (ECs) can modulate ATP secretion to regulate the pathogenesis of AAA formation. Our hypothesis focused on potential of spironolactone to inhibit EC-mediated ATP release for the mitigation of AAA formation.

Methods

A topical elastase AAA model was used initially in C57BL/6 (wild-type; WT) male mice. Mice were administered either a vehicle control (saline) or spironolactone and analyzed on day 14. In a second chronic AAA model, mice were subjected to elastase and β-aminopropionitrile (BAPN) treatment with/without administration of spironolactone to pre-formed aneurysms starting on day 14 and analyzed on day 28. Aortic diameter was evaluated by video micrometry and aortic tissue was analyzed for cytokine expression and histology. ATP measurement and matrix metalloproteinase (MMP2) activity was evaluated in aortic tissue on days 14 or -28. In vitro studies were performed to evaluate the crosstalk between aortic ECs with macrophages or smooth muscle cells.

Results

In the elastase AAA model, spironolactone treatment displayed a significant decrease in aortic diameter compared to elastase-treated controls on day 14. A significant increase in smooth muscle α-actin expression as well as decrease in elastic fiber disruption and immune cell (macrophages and neutrophils) infiltration was observed in mice treated with spironolactone compared to saline-treated controls. Spironolactone treatment also significantly mitigated pro-inflammatory cytokine expression, MMP2 activity and ATP content in aortic tissue compared to controls. Moreover, in the chronic AAA model, spironolactone treatment of pre-formed aneurysms significantly attenuated vascular inflammation and remodeling to attenuate the progression of AAAs compared to controls. Mechanistically, in vitro data demonstrated that spironolactone treatment attenuates extracellular ATP release from endothelial cells to mitigate macrophage activation (IL-1β and HMGB1 expression) and smooth muscle cell-dependent vascular remodeling (MMP2 activity).

Conclusion

These results demonstrate that spironolactone can mitigate aortic inflammation and remodeling to attenuate AAA formation as well as decrease growth of pre-formed aneurysms via inhibition of EC-dependent ATP release. Therefore, this study implicates a therapeutic application of spironolactone in the treatment of AAAs.

Identification of core cuprotosis-correlated biomarkers in abdominal aortic aneurysm immune microenvironment based on bioinformatics

Background

The occurrence of abdominal aortic aneurysms (AAAs) is related to the disorder of immune microenvironment. Cuprotosis was reported to influence the immune microenvironment. The objective of this study is to identify cuprotosis-related genes involved in the pathogenesis and progression of AAA.

Methods

Differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) in mouse were identified following AAA through high-throughput RNA sequencing. The enrichment analyses of pathway were selected through Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG). The validation of cuprotosis-related genes was conducted through immunofluorescence and western blot analyses.

Results

Totally, 27616 lncRNAs and 2189 mRNAs were observed to be differentially expressed (|Fold Change| ≥ 2 and q< 0.05) after AAA, including 10424 up-regulated and 17192 down-regulated lncRNAs, 1904 up-regulated and 285 down-regulated mRNAs. Gene ontology and KEGG pathway analysis showed that the DElncRNAs and DEmRNAs were implicated in many different biological processes and pathways. Furthermore, Cuprotosis-related genes (NLRP3, FDX1) were upregulated in the AAA samples compared with the normal one.

Conclusion

Cuprotosis-related genes (NLRP3,FDX1) involved in AAA immune environment might be critical for providing new insight into identification of potential targets for AAA therapy.

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.

Combination of folic acid with nifedipine is completely effective in attenuating aortic aneurysm formation as a novel oral medication

Aortic aneurysms are prevalent and severe vascular diseases with high mortality from unpredicted ruptures, while the only treatment option is surgical correction of large aneurysms with considerable risk. We have shown that folic acid (FA) is highly effective in alleviating development of aneurysms although not sufficient to completely attenuate aneurysm formation. Here, we examined therapeutic effects on aneurysms of combining FA with Nifedipine as novel and potentially more effective oral medication. Oral administration with FA (15 mg/kg/day) significantly reduced incidence of AAA from 85.71% to 18.75% in Ang II-infused apolipoprotein E (apoE) null mice, while combination of FA with Nifedipine (1.5, 5.0 or 20 mg/kg/day) substantially and completely further reduced incidence of AAA to 12.5%, 11.76% and 0.00% respectively in a dose-dependent manner. The combinatory therapy substantially and completely further alleviated enlargement of abdominal aortas defined by ultrasound, vascular remodeling characterized by elastin degradation and adventitial hypertrophy, as well as aortic superoxide production and eNOS uncoupling activity also in a dose-dependent manner, with combination of FA with 20 mg/kg/day Nifedipine attenuating all of these features by 100% to control levels. Aortic NO and H4B bioavailabilities were also dose-dependently further improved by combining FA with Nifedipine. These data establish entirely innovative and robust therapeutic regime of FA combined with Nifedipine for the treatment of aortic aneurysms. The comminatory therapy can serve as a first-in-class and most effective oral medication for aortic aneurysms, which can be rapidly translated into clinical practice to revolutionize management of the devastating vascular diseases of aortic aneurysms known as silent killers.

A Multi-Bioactive Nanomicelle-Based "One Stone for Multiple Birds" Strategy for Precision Therapy of Abdominal Aortic Aneurysms

Abdominal aortic aneurysm (AAA) remains a lethal aortic disease in the elderly. Currently, no effective drugs can be clinically applied to prevent the development of AAA. Herein, a "one stone for multiple birds" strategy for AAA therapy is reported. As a proof of concept, three bioactive conjugates are designed and synthesized, which can assemble into nanomicelles. Cellularly, these nanomicelles significantly inhibit migration and activation of inflammatory cells as well as protect vascular smooth muscle cells (VSMCs) from induced oxidative stress, calcification and apoptosis, with the best effect for nanomicelles (TPTN) derived from a conjugate defined as TPT. After intravenous delivery, TPTN efficiently accumulates in the aneurysmal tissue of AAA rats, showing notable distribution in neutrophils, macrophages and VSMCs, all relevant to AAA pathogenesis. Whereas three examined nanomicelles effectively delay expansion of AAA in rats, TPTN most potently prevents AAA growth by simultaneously normalizing the pro-inflammatory microenvironment and regulating multiple pathological cells. TPTN is effective even at 0.2 mg kg^-1 . Besides, TPTN can function as a bioactive nanoplatform for site-specifically delivering and triggerably releasing anti-aneurysmal drugs, affording synergistic therapeutic effects. Consequently, TPTN is a promising multi-bioactive nanotherapy and bioresponsive targeting delivery nanocarrier for effective therapy of AAA and other inflammatory vascular diseases.

Edaravone Attenuated Angiotensin II-Induced Atherosclerosis and Abdominal Aortic Aneurysms in Apolipoprotein E-Deficient Mice

Background: The aim of the study was to define whether edaravone, a free-radical scavenger, influenced angiotensin II (AngII)-induced atherosclerosis and abdominal aortic aneurysms (AAAs) formation. Methods: Male apolipoprotein E-deficient mice (8–12 weeks old) were fed with a normal diet for 5 weeks. Either edaravone (10 mg/kg/day) or vehicle was injected intraperitoneally for 5 weeks. After 1 week of injections, mice were infused subcutaneously with either AngII (1000 ng/kg/min, n = 16–17 per group) or saline (n = 5 per group) by osmotic minipumps for 4 weeks. Results: AngII increased systolic blood pressure equivalently in mice administered with either edaravone or saline. Edaravone had no effect on plasma total cholesterol concentrations and body weights. AngII infusion significantly increased ex vivo maximal diameters of abdominal aortas and en face atherosclerosis but was significantly attenuated by edaravone administration. Edaravone also reduced the incidence of AngII-induced AAAs. In addition, edaravone diminished AngII-induced aortic MMP-2 activation. Quantitative RT-PCR revealed that edaravone ameliorated mRNA abundance of aortic MCP-1 and IL-1β. Immunostaining demonstrated that edaravone attenuated oxidative stress and macrophage accumulation in the aorta. Furthermore, edaravone administration suppressed thioglycolate-induced mice peritoneal macrophages (MPMs) accumulation and mRNA abundance of MCP-1 in MPMs in male apolipoprotein E-deficient mice. In vitro, edaravone reduced LPS-induced mRNA abundance of MCP-1 in MPMs. Conclusions: Edaravone attenuated AngII-induced AAAs and atherosclerosis in male apolipoprotein E-deficient mice via anti-oxidative action and anti-inflammatory effect.

Exosomal miR-17-5p from adipose-derived mesenchymal stem cells inhibits abdominal aortic aneurysm by suppressing TXNIP-NLRP3 inflammasome

Background

Preclinical studies have suggested that adipose-derived mesenchymal stem cells (ADSCs) transplantation can suppress abdominal aortic inflammation and aneurysm expansion through paracrine factors. Yet, the mechanism of action is not fully understood. In the present study, we further examined the function and mechanism of ADSC-derived exosomes (ADSC-exos) and their microRNA-17-5p (miR-17-5p) on the abdominal aortic aneurysm (AAA) progression.

Methods

ADSC-exos were isolated and identified. DiR and PKH67 staining were used to trace ADSC-exo in vivo and in vitro. Raw264.7 cells were applied to perform in vitro experiments, while a murine AAA model induced using angiotensin II (Ang II) was used for in vivo testing. The expression level of miR-17-5p in macrophages and Ang II-treated macrophages after ADSC-exos treatment was determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The target relation between miR-17-5p and thioredoxin-interacting protein (TXNIP) was identified by a dual-luciferase reporter gene assay. Artificial activation and block of experiments of miR-17-5p and TXNIP were conducted to clarify their functions in inflammation during AAA progression. The severity of AAA between groups was assessed by maximal aorta diameter, AAA incidence, survival rate, and histological stainings. Besides, inflammasome-related proteins and macrophage pyroptosis were further evaluated using western blot, RT-qPCR, and enzyme-linked immunosorbent assay (ELISA).

Results

The ADSC-exos were isolated and identified. In vivo testing showed that ADSC-exos were mainly distributed in the liver. Meanwhile, in vitro experiments suggested that ADSC-derived exosomes were taken up by macrophages, while inside, ADSC-exos miR-17-5p decreased a TXNIP induced by Ang II by directly binding to its 3′-untranslated region (3’UTR). Furthermore, overexpression of miR-17-5p enhanced the therapeutic function of ADSC-exos on inflammation during AAA expansion in vivo, while its inhibition reversed this process. Finally, overexpressed TXNIP triggered macrophage pyroptosis and was alleviated by ADSC-derived exosomes in vitro.

Conclusion

ADSC-exos miR-17-5p regulated AAA progression and inflammation via the TXNIP-NLRP3 signaling pathway, thus providing a novel insight in AAA treatment.

Endovascular versus open repair in patients with abdominal aortic aneurysm: a claims-based data analysis in Japan

Objectives

Endovascular aortic repair (EVAR) evolved through competition with open aortic repair (OAR) as a safe and effective treatment option for appropriately selected patients with abdominal aortic aneurysm (AAA). Although endoleaks are the most common reason for post-EVAR reintervention, compliance with lifelong regular follow-up imaging remains a challenge.

Design

Retrospective data analysis.

Setting

The Japan Medical Data Center (JMDC), a claims database with anonymous data linkage across hospitals, consists of corporate employees and their families of ≤75 years of age.

Participants

The analysis included participants in the JMDC who underwent EVAR or OAR for intact (iAAA) or ruptured (rAAA) AAA. Patients with less than 6 months of records before the aortic repair were excluded.

Main outcome measures

Overall survival and reintervention rates.

Results

We identified 986 cases (837 iAAA and 149 rAAA) from JMDC with first aortic repairs between January 2015 and December 2020. The number of patients, median age (years (IQR)), follow-up (months) and post-procedure CT scan (times per year) were as follows: iAAA (OAR: n=593, 62.0 (57.0–67.0), 26.0, 1.6, EVAR: n=244, 65.0 (31.0–69.0), 17.0, 2.2), rAAA (OAR: n=110, 59.0 (53.0–59.0), 16.0, 2.1, EVAR: n=39, 62.0 (31.0–67.0), 18.0, 2.4). Reintervention rate was significantly higher among EVAR than OAR in rAAA (15.4% vs 8.2%, p=0.04). In iAAA, there were no group difference after 5 years (7.8% vs 11.0%, p=0.28), even though EVAR had initial advantage. There were no differences in mortality rate between EVAR and OAR for either rAAA or iAAA.

Conclusions

Claims-based analysis in Japan showed no statistically significant difference in 5-year survival rates of the OAR and EVAR groups. However, the reintervention rate of EVAR in rAAA was significantly higher, suggesting the need for regular post-EVAR follow-up with imaging. Therefore, international collaborations for long-term outcome studies with real-world data are warranted.