Abdominal aortic aneurysm: update on pathogenesis and medical treatments

A computed tomography angiography-based radiomics model for prognostic prediction of endovascular abdominal aortic repair

OBJECTIVE

This study aims to develop a radiomics machine learning (ML) model that uses preoperative computed tomography angiography (CTA) data to predict the prognosis of endovascular aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA) patients.

METHODS

In this retrospective study, 164 AAA patients underwent EVAR and were categorized into shrinkage (good prognosis) or stable (poor prognosis) groups based on post-EVAR sac regression. From preoperative AAA and perivascular adipose tissue (PVAT) image, radiomics features (RFs) were extracted for model creation. Patients were split into 80 % training and 20 % test sets. A support vector machine model was constructed for prediction. Accuracy is evaluated via the area under the receiver operating characteristic curve (AUC).

RESULTS

Demographics and comorbidities showed no significant differences between shrinkage and stable groups. The model containing 5 AAA RFs (which are original_firstorder_InterquartileRange, log-sigma-3-0-mm-3D_glrlm_GrayLevelNonUniformityNormalized, log-sigma-3-0-mm-3D_glrlm_RunPercentage, log-sigma-4-0-mm-3D_glrlm_ShortRunLowGrayLevelEmphasis, wavelet-LLH_glcm_SumEntropy) had AUCs of 0.86 (training) and 0.77 (test). The model containing 7 PVAT RFs (which are log-sigma-3-0-mm-3D_firstorder_InterquartileRange, log-sigma-3-0-mm-3D_glcm_Correlation, wavelet-LHL_firstorder_Energy, wavelet-LHL_firstorder_TotalEnergy, wavelet-LHH_firstorder_Mean, wavelet-LHH_glcm_Idmn, wavelet-LHH_glszm_GrayLevelNonUniformityNormalized) had AUCs of 0.76 (training) and 0.78 (test). Combining AAA and PVAT RFs yielded the highest accuracy: AUCs of 0.93 (training) and 0.87 (test).

CONCLUSIONS

Radiomics-based CTA model predicts aneurysm sac regression post-EVAR in AAA patients. PVAT RFs from preoperative CTA images were closely related to AAA prognosis after EVAR, enhancing accuracy when combined with AAA RFs. This preliminary study explores a predictive model designed to assist clinicians in optimizing therapeutic strategies during clinical decision-making processes.

The associations between circulating amino acids and arterial aneurysms and dissection: A bidirectional Mendelian randomization study

Background

Circulating amino acid levels can be altered in arterial aneurysms and dissection, but the relationships between them is unclear. The present study investigated the causal relationship between circulating amino acid levels and arterial aneurysms and dissection via bidirectional two-sample Mendelian randomization (MR).

Methods

A bidirectional two-sample MR analysis was used. Forward analysis was performed with amino acid levels as the exposure and arterial aneurysms and dissection as outcomes. Reverse analysis was performed with arterial aneurysms and dissection as exposures and circulating amino acid levels as outcomes. MR data were analyzed using five analytical methods: the inverse-variance weighted (IVW), MR‒Egger, weighted median, simple, and weighted methods. IVW was used as the main analytical method, and the other methods were used for supplementary analyses. Heterogeneity was assessed using Cochran's Q test, and horizontal pleiotropy was assessed using intercepts from MR‒Egger regression. The genome-wide association study (GWAS) data for circulating amino acids were obtained from the IEU open GWAS database and the GWAS Catalog database. The GWAS data for arterial aneurysms and dissection were obtained from the Finngen consortium database version R10.

Results

The tyrosine level was negatively correlated with other aneurysms (P = 0.00211, OR: 0.57, 95 % CI: 0.40, 0.82). Aortic dissection decreased the circulating glycine level (P = 0.00168, OR: 0.98, 95 % CI: 0.98, 0.99).

Conclusion

Through bidirectional MR analysis, we found that tyrosine level was negatively correlated with other aneurysms and that aortic dissection reduced circulating glycine. Our findings support a possible interaction between circulating amino acid levels and arterial aneurysms and dissection.

Endothelial miR-34a deletion guards against aneurysm development despite endothelial dysfunction

We previously reported a link between NRF2, a cytoprotective transcription factor, and the ageing of endothelial cells (ECs) and aorta. We also found that NRF2 KO mice are more susceptible to the development of abdominal aortic aneurysm (AAA), which is an age-associated condition. Since miR-34a is a marker of ageing, we explored its relationship with NRF2 and its role in vascular function and AAA formation. Here, we demonstrate that premature NRF2-dependent ageing of ECs is mediated by miR-34a. Infusion of hypertensive angiotensin II (Ang II) in mice increases miR-34a in the aortic endothelial layer and serum, particularly in mice developing AAA. Mice lacking endothelial miR-34a exhibit severe EC dysfunction. Despite that, they are protected from AAA, also on the NRF2 KO background. This protective effect is reversed by rapamycin, which suppresses Ang II-induced EC proliferation. We identified MTA2, but not SIRT1, as a target of miR-34a that inhibits EC proliferation stimulated by Ang II. These findings suggest that fine-tuning of EC proliferation could have potential therapeutic implications for the treatment of aneurysms.

Macrophage heme oxygenase-1 modulates peroxynitrite-mediated vascular injury and exacerbates abdominal aortic aneurysm development

Inflammatory reactions mediated by macrophages are profoundly related to the depletion of smooth muscle cells (SMCs) in abdominal aortic aneurysm (AAA) development. The findings from our previous investigation indicate that heme oxygenase-1 (HO-1) in macrophages exacerbates proinflammatory responses and oxidative damage. Therefore, the aim of this work was to gain insight into the function of HO-1 derived from macrophages and elucidate the underlying molecular mechanisms involved in AAA development. In this study, we discovered a dramatic increase in HO-1 expression in the infiltrated macrophages in experimental calcium phosphate-induced AAA tissues. Myeloid conditional HO-1-deficient mice displayed slower luminal area enlargement, as well as diminished inducible nitric oxide synthase (iNOS)-positive M1 macrophage activation, peroxynitrite generation, and SMCs apoptosis in aneurysmal tissues compared with littermate controls. Furthermore, we showed that inhibiting HO-1 eliminated the protein expression of iNOS induced by lipopolysaccharide/interferon-γ in bone marrow-derived macrophages, whereas the mRNA expression remained unaffected. Suppressing iNOS in macrophages alleviated SMCs apoptosis by decreasing nitric oxide generation in a coculture system in vitro. In summary, our study illustrates that macrophage-derived HO-1 strengthens AAA development through boosting the production of iNOS-dependent peroxynitrite and the deterioration of SMCs. These findings reveal potential therapeutic targets for resolving aneurysmal diseases.NEW & NOTEWORTHY This article illustrates the role of macrophage-derived heme oxygenase-1 (HO-1) in the development of abdominal aortic aneurysm (AAA). HO-1 deletion in macrophages hindered AAA development by reducing inducible nitric oxide synthase (iNOS)-dependent peroxynitrite production and smooth muscle cells (SMCs) apoptosis in vivo. Mechanistically, inhibition of HO-1 reduced the stimulated iNOS protein production in macrophages by lipopolysaccharide/interferon-γ. Moreover, suppressing iNOS in macrophages prevented SMCs apoptosis by decreasing nitric oxide generation in vitro.

GDF15 suppresses abdominal aortic aneurysm by upregulating AREG expression to adjust macrophage polarization

OBJECTIVE

Inflammation plays a key role in abdominal aortic aneurysm (AAA), with macrophages being crucial. Growth differentiation factor 15 (GDF15) is a new anti-inflammatory cytokine potentially useful in AAA diagnosis and treatment, but its role is unclear.

METHODS AND RESULTS

In mice with AAA, GDF15 expression was higher in lesioned tissues. Daily intraperitoneal injection of recombinant GDF15 (rGDF15) reduced aortic dilation, inflammation, degradation of aortic wall elastin and collagen, cellular apoptosis, and increased smooth muscle cells. GDF15 knockdown worsened AAA severity. Immunohistochemistry and immunofluorescence showed rGDF15 treatment reduced M1 macrophage polarization and enhanced M2 polarization, decreasing the M1/M2 ratio. GDF15 knockdown had the opposite effect. Additionally, Amphiregulin (AREG) expression increased with rGDF15 treatment and decreased with GDF15 knockdown. Immunofluorescence colocalization revealed lower AREG expression in M1 macrophages and higher AREG expression in M2 macrophages, suggesting that AREG may be involved in the regulation of macrophage polarization by GDF15 in AAA. Mechanistically, GDF15 upregulates AREG expression by activating the TGF-βR/SMAD2/3 signaling pathway, thereby inhibiting M1 polarization and promoting M2 polarization of macrophages.

CONCLUSION

This study demonstrates that exogenous injection of rGDF15 upregulates AREG expression and regulates macrophage polarization, thereby inhibiting AAA. GDF15 may not only serve as a diagnostic and prognostic marker for AAA but also as a potential molecular target for therapeutic intervention in AAA.

Myeloid Cells in Abdominal Aortic Aneurysm

PURPOSE OF REVIEW

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disorder with high mortality upon rupture, yet effective pharmacotherapy remains lacking. This review synthesizes the pivotal roles of myeloid cells-key mediators of aortic inflammation and remodeling-in AAA pathogenesis, highlighting their therapeutic targeting potential.

RECENT FINDINGS

Single-cell RNA sequencing has revealed myeloid diversity in AAA. Among these myeloid populations, macrophages (including interferon-responsive monocytes, pro- and anti-inflammatory subsets, and reparative populations) emerge as central regulators of AAA pathogenesis, influencing disease initiation, progression, and tissue repair processes. Neutrophils promote vascular injury via neutrophil extracellular traps, while dendritic cells bridge innate-adaptive immunity. Eosinophils and myeloid-derived suppressor cells exhibited protective effects by immunoregulation. Mechanistic studies identified transcriptional, metabolic, and epigenetic regulators of myeloid plasticity. Clonal hematopoiesis and trained immunity may serve as potential novel mechanisms of myeloid cells involved in AAA. These mechanistic insights have inspired therapeutic innovation, with nanoparticle-targeted myeloid cell therapies showing promising immunomodulatory effects in mitigating AAA progression. Myeloid cells play a pivotal role in AAA pathogenesis by driving inflammatory responses, extracellular matrix degradation, and maladaptive vascular remodeling. Their functional heterogeneity, encompassing both destructive and protective subsets, highlights the need for precisely targeted therapeutic approaches. While single-cell technologies have significantly advanced our understanding of myeloid diversity, clinical translation remains challenged by microenvironmental crosstalk and potential off-target effects. Future research should prioritize: (1) spatial multi-omics characterization of myeloid-vascular interactions, (2) development of precision therapies targeting clonal hematopoiesis-driven subpopulations, and (3) combinatorial strategies to reprogram pathogenic myeloid phenotypes. Addressing these critical gaps may lead to transformative therapies for aneurysm stabilization, ultimately fulfilling the urgent unmet needs in AAA clinical management.

SM22α-Lineage Perivascular Stromal Cells Contribute to Abdominal Aortic Aneurysm

BACKGROUND

Perivascular adipose tissue (PVAT) is a key regulator of vascular dysfunction. Impairment of PVAT phenotypic plasticity with aging may play a role in vascular pathology including abdominal aortic aneurysms (AAAs). Yet, the mechanisms underlying PVAT plasticity in aneurysm pathogenesis remain elusive.

METHODS

Single-cell RNA sequencing was performed on perivascular stromal cells from young (2- to 3-month-old) and aged (18- to 20-month-old) mice. The expression of PGC-1α (peroxisome proliferator-activated receptor gamma coactivator-1α) was measured in PVAT of aged mice and human aneurysm samples. Loss- and gain-of-function approaches were used to investigate the role of SM22α-lineage perivascular stromal cell-derived PGC-1α in aneurysm development. Molecular mechanisms were explored through transcriptome and functional studies in young and aged mice, SM22αCre; Rosa26RFP/+; PGC1αf/f and SM22αCre; Rosa26RFP/+ mice with Ang II (angiotensin II)-induced and deoxycorticosterone acetate/salt-induced AAA models.

RESULTS

SM22α+ cells accumulated in PVAT of Ang II-treated aged mice and patients with aortic aneurysms. Single-cell RNA sequencing analysis revealed that aging disrupted the differentiation potential of SM22α-lineage perivascular stromal cells and led to reduced PGC-1α levels. PGC1α downregulation in PVAT was observed in both mouse AAA models and human aneurysm lesions. In mice with SM22α-driven PGC-1α deletion, Ang II-induced AAA formation was accompanied by perivascular stromal cell-to-myofibroblast differentiation. In vitro PGC1α knockdown suppressed nuclear YAP (Yes-associated protein) signaling, reducing adipocyte differentiation, while increasing MMP2 (matrix metalloproteinase 2)-secreting myofibroblasts. Furthermore, PGC-1α overexpression in aged mice or administration of the YAP signaling inhibitor verteporfin in SM22αCre; Rosa26RFP/+; PGC1αf/f mice restored PVAT function and conferred protection against aneurysm formation. Last, we used the radiomics analysis to noninvasively evaluate PVAT in the context of AAA severity in humans.

CONCLUSIONS

PGC-1α deficiency in SM22α-lineage stromal cells disrupts the balance between adipogenic and myofibrogenic differentiation through regulating YAP signaling, ultimately promoting aneurysm development. Radiomics assessment may present a promising noninvasive approach for PVAT evaluation in aneurysms, offering valuable potential for clinical research.

Clonal Hematopoiesis of Indeterminate Potential Is Associated With Incident Abdominal Aortic Aneurysm

BACKGROUND

Clonal hematopoiesis of indeterminate potential (CHIP) is an emerging risk factor for cardiovascular diseases. Genetic IL (interleukin)-6 signaling deficiency reduced cardiovascular disease risk in CHIP carriers. However, the association between CHIP and incident abdominal aortic aneurysm (AAA) and whether IL-6 signaling inhibition attenuates AAA risk among individuals with CHIP remained unclear.

METHODS

Participants without prevalent AAA from the UK Biobank were included. The associations of any CHIP (variant allele fraction, ≥2%), large CHIP (variant allele fraction, ≥10%), and gene-specific CHIP subtypes with incident AAA were investigated. The protection role of IL6R p.Asp358Ala, a genetic proxy for IL-6 deficiency, was tested after stratification by CHIP status. Furthermore, the interaction and joint effects of CHIP and genetic susceptibility on AAA risk were tested.

RESULTS

This study included 425 211 participants. Any CHIP and large CHIP was identified in 13 768 (3.2%) and 8576 (2.0%) participants, respectively. CHIP was associated with an increased risk of incident AAA (hazard ratio [HR], 1.21 [95% CI, 1.01-1.44]; P=0.034), with large CHIP clones exhibiting greater effect size (HR, 1.35 [95% CI, 1.10-1.66]; P=0.0045). Driver gene-specific analyses revealed that ASXL1-mediated CHIP exerted the strongest effect size on AAA risk (HR, 2.10 [95% CI, 1.54-2.88]; P<0.001). The presence of 2 IL6R p.Asp358Ala alleles attenuated the risk of AAA in large CHIP carriers (HR, 0.48 [95% CI, 0.23-0.99]; P=0.046). In the joint analysis, participants with CHIP and high genetic risk had a higher risk of developing AAA than those without CHIP and with low genetic risk (HR, 2.15 [95% CI, 1.63-2.85]; P<0.001).

CONCLUSIONS

CHIP is associated with an increased risk of AAA. Genetic IL-6 signaling deficiency attenuates the risk of AAA in large CHIP carriers. CHIP may serve as an attractive target for the prevention and treatment of AAA.

Revealing shared molecular and mechanistic signatures between intracranial aneurysms and abdominal aortic aneurysms: a comprehensive genomic analysis

Intracranial aneurysms (IAs) and abdominal aortic aneurysms (AAAs) are both vascular diseases that are closely linked. However, the pathogenesis underlying the co-occurrence of IAs and AAAs remains poorly understood. This study aims to identify key biomarkers that shed light on the molecular mechanisms connecting these two diseases using bioinformatics analysis. Gene expression profiles (GSE122897, GSE237229) were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) common to both IAs and AAAs were identified and subjected to functional enrichment analysis. The Cytoscape cytoHubba plugin was used to identify hub genes, and their predictive ability was evaluated using the receiver operating characteristic (ROC) curve. Additionally, immune infiltration analyses and single-gene gene set enrichment analysis (GSEA) were conducted for the hub genes. A total of 46 DEGs were identified, including 40 upregulated genes and 6 downregulated genes. The common DEGs were found to be involved in extracellular matrix structural constituents, collagen fibril organization, and regulation of basic cellular processes. ITGA11 was identified as a key gene implicated in the comorbidity of IAs and AAAs, with its upregulation strongly associated with plasma cells. Furthermore, in both IAs and AAAs, glycosaminoglycan biosynthesis of extracellular matrix components and immune-related diseases were significantly linked to the high expression of ITGA11. Our findings suggest that the comorbidity of IAs and AAAs may be driven by shared inflammatory and immune response mechanisms, with ITGA11 emerging as a potential biomarker for this co-occurrence.

Cyclodextrin-Derived Macromolecular Therapies for Inflammatory Diseases

Inflammation is an essential physiological defense mechanism against harmful stimuli, yet dysregulated inflammatory responses are closely associated with the pathogenesis of numerous acute and chronic diseases. Recent advances highlight the remarkable anti-inflammatory potential of bioactive macromolecules, particularly cyclodextrins (CDs) and their engineered derivatives, which are emerging as promising therapeutic agents. This review systematically introduces different CDs and CD-derived macromolecules that demonstrate anti-inflammatory properties, with emphasis on their molecular mechanisms of action. Native CDs exhibit direct therapeutic effects through host-guest interactions, enabling selective sequestration of pathogenic components such as cholesterol crystals and proteins that drive inflammatory cascades. Moreover, chemically modified CD derivatives incorporating functional groups demonstrate enhanced capabilities in neutralizing inflammatory mediators and modulating immune cell responses. This work further discusses the expanding therapeutic applications of these macromolecules across diverse inflammatory conditions, ranging from acute tissue injuries to chronic autoimmune disorders. Finally, this work critically analyzes the crucial challenges and emerging opportunities in translating CD-based macromolecular therapies into clinical practice, addressing key considerations in biocompatibility, targeted delivery, and therapeutic efficacy optimization.

Endovascular repair of abdominal aortic aneurysm-related type II endoleak: a multicenter study on the possibility of further intervention

Background

We aimed to analyze the risk factors associated with Type II endoleak (T2EL) requiring reintervention after endovascular aneurysm repair (EVAR) for multicenter abdominal aortic aneurysms.

Methods

A retrospective analysis was conducted on data from 614 patients with abdominal aortic aneurysms who underwent elective EVAR at three centers (Tianjin Medical University General Hospital, Affiliated Hospital of Inner Mongolia Medical University, Shanxi Provincial People's Hospital) from January 2017 to December 2021. After applying exclusion criteria, 375 patients were included in the study, with 50 patients in the T2EL-related reintervention group and 325 patients in the non-T2EL group. Single-factor and multiple-factor logistic analyses were used to identify high-risk factors, and ROC curve analysis was performed to determine the risk thresholds for mesenteric artery diameter, number of lumbar arteries, maximum aneurysm diameter, and proportion of intraluminal thrombus volume.

Results

The rate of T2EL-related reintervention among the 375 patients was 13.33% (50/375). Single-factor analysis indicated that age, hypertension, maximum aneurysm diameter, proportion of intraluminal thrombus, diameter of inferior mesenteric artery (IMA), and number of patent lumbar arteries (LA) were risk factors for T2EL-related reintervention. Multiple-factor logistic analysis identified maximum aneurysm diameter, proportion of thrombus, IMA diameter, and number of patent LA as the main influencing factors for T2EL-related reintervention after EVAR. Significant risk factors for reintervention were maximum aneurysm diameter (OR = 1.043, 95% CI 1.015-1.072, P = 0.002), IMA diameter (OR = 3.901, 95% CI 1.116-13.632, P = 0.033), and number of LA (OR = 2.584, 95% CI 1.722-3.769, P < 0.001). A significant protective factor for reintervention was thrombus proportion (OR = 0.895, 95% CI 0.864-0.927, P < 0.001). ROC curve analysis showed that the risk thresholds for reintervention were an IMA diameter of 2.95 mm, intraluminal thrombus volume proportion <42.5%, number of LA ≤5.5, and aneurysm diameter of 53.55 mm.

Conclusion

Cases with identified risk factors are considered to have a higher risk of T2EL-related reintervention after EVAR. Exceeding the new risk thresholds may indicate a higher likelihood of T2EL-related reintervention after EVAR.

RAGE deficiency ameliorates abdominal aortic aneurysm progression

BACKGROUND

Abdominal aortic aneurysm (AAA) is a vascular disease characterized by inflammation and arterial wall degradation. The receptor for advanced glycation end products (RAGE) plays a pivotal role in regulating inflammatory pathways, but its specific contribution to AAA pathogenesis remains unclear.

PURPOSE

This study aimed to investigate the role of RAGE in AAA development by examining its expression in human and mice AAA tissues and exploring the effects of RAGE deficiency on aneurysm progression, macrophage polarization, and inflammatory responses.

METHODS

RAGE expression was analyzed in human AAA samples and porcine pancreatic elastase (PPE) induced AAA mouse models using Western blotting, immunohistochemistry, and immunofluorescence. In vivo RAGE-deficient (RAGE-/-) mice were generated to assess the impact of RAGE knockout on AAA progression. In vitro experiments utilized RAW264.7 transfected with RAGE-targeting siRNA to study macrophage polarization and NF-κB signaling.

RESULTS

RAGE expression was elevated in AAA tissues, particularly in macrophages. RAGE-/- mice exhibited reduced AAA incidence, mortality, and aortic dilation compared to wild-type mice. Histological analysis showed preserved elastic fibers and smooth muscle layers, along with decreased inflammatory cell infiltration and MMP2/MMP9 expression. RAGE deficiency inhibited M1-like macrophage polarization and pro-inflammatory cytokine secretion, mediated through suppression of the NF-κB pathway.

CONCLUSIONS

RAGE deficiency mitigates AAA progression by modulating macrophage polarization and reducing inflammation via the NF-κB pathway. These findings highlight RAGE as a potential therapeutic target for AAA treatment.

Deficiency of IL-7R attenuates abdominal aortic aneurysms in mice by inhibiting macrophage polarization towards M1 phenotype through the NF-κB pathway

BACKGROUND

Abdominal aortic aneurysm (AAA) is a common degenerative disease of the abdominal aorta, which can result in extremely high mortality owing to the rupture of the abdominal aorta. The activation of IL-7R has been shown to modulate the inflammatory responses, which play an important role in the progression of AAAs. However, the mechanism of IL-7/IL-7R axis in AAAs is still unclear.

AIMS

This study aims to investigate the effects of IL-7R on AAAs and the underlying mechanisms involved.

METHODS

Wild-type C57BL/6 and IL-7R knockout mice were used as experimental subjects. ELISA analysis, histological staining, western blotting and qPCR were performed to explore effects of IL-7R deficiency in the formation and development of elastase-induced AAAs. Transwell, CCK8, and immunofluorescence assays detected the migration and polarization of RAW264.7 macrophages in vitro.

RESULT

We demonstrated that IL-7R was elevated in mice with AAAs. Blocking IL-7R can inhibit the formation of AAAs and reduce aortic dilatation, elastic layer degradation, and inflammatory cell infiltration. Knockout of IL-7R suppressed the migration, infiltration and M1 polarization of macrophages. Moreover, inhibition of the NF-κB signaling pathway by BAY 11-7082 attenuated the macrophage-mediated inflammatory responses caused by IL-7R overexpression.

CONCLUSION

In short, this study showed that IL-7R promotes the infiltration and migration of macrophages by regulating M1 macrophage polarization, possibly in part via activation of the NF-κB pathway, which may be associated with the development of AAAs.

Oxidative stress in vascular surgical diseases: mechanisms, impacts and therapeutic perspectives

The role of oxidative stress in vascular surgical diseases has increasingly been recognized as significant. This paper systematically reviews the specific mechanisms of oxidative stress in a various vascular surgical condition, including aortic dissection, abdominal aortic aneurysm, thrombosis, diabetic foot, and thromboangiitis obliterans, while also exploring related therapeutic strategies. Oxidative stress arises from an imbalance between free radicals and antioxidants, where excess reactive oxygen species and other free radicals can exacerbate inflammatory response. This paper delves into the pathogenic mechanisms of oxidative stress in the aforementioned diseases and discusses potential methods for utilizing antioxidants to reduce oxidative stress levels. Additionally, this paper highlights the challenges faced by current antioxidant therapies and identifies future research directions. By summarizing current research progress, this paper aims to provide a theoretical basis for more effective treatment strategies of vascular surgical diseases, with the hope of advancing the field.

Abdominal Aortic Aneurysm and Liver Fibrosis: Clinical Evidence and Molecular Pathomechanisms

To stimulate further research, this review summarizes studies linking liver fibrosis with the risk of abdominal aortic aneurysms (AAA). AAA is defined as a permanently weakened and dilated abdominal aorta, which develops due to inflammation of the tunica media, activation of the renin-angiotensin-aldosterone system, immune system activation, and coagulation disorders. Typically asymptomatic, AAA is often incidentally detected through imaging done for abdominal symptoms or as part of screening programs. AAA follows a variable course and has a mortality rate strongly dependent on age and sex. Risk factors for AAA include age, male sex, ethnicity, family history of AAA, lifestyle habits, arterial hypertension, dyslipidemia, and comorbid atherosclerotic cardiovascular disease. Conversely, individuals with type 2 diabetes, female sex, and certain ethnicities are at a reduced risk of AAA. Liver fibrosis, resulting from chronic liver diseases owing to varying etiologies, is increasingly recognized as a potential contributor to AAA development. Evidence increasingly indicates that metabolic dysfunction-associated steatotic liver disease (MASLD) and other chronic liver conditions may intensify inflammatory pathways shared with AAA, thereby potentially exacerbating AAA progression. This review specifically examines the epidemiology and risk factors associated with the link between AAA and liver fibrosis. It also highlights potential pathomechanisms, including systemic inflammation, oxidative stress, and extracellular matrix remodeling, which may contribute to both conditions. Although these findings underscore significant overlaps in risk profiles, additional research is needed to clarify whether type 2 diabetes, female sex, and certain ethnicities truly confer protection against AAA or if this association is influenced by other confounding variables. Ultimately, addressing these open questions will help guide targeted therapeutic interventions and the identification of novel biomarkers to predict disease progression.

Causal relationship between mitochondrial proteins and risks of aortic aneurysms and aortic dissection: a Mendelian randomization study

BACKGROUND

Mitochondrial dysfunction may be linked to the development of aortic aneurysm (AA) and aortic dissection (AD). This study aimed to evaluate the potential associations between proteins related to mitochondrial function and the risks of AA/AD using Mendelian randomization (MR).

METHODS

Large-scale publicly available genome-wide association studies (GWAS) and FinnGen summary data were utilized for MR analysis. The causal relationship between mitochondrial proteins and AA/AD was assessed using inverse-variance weighted (IVW) as the primary method. Sensitivity analyses were conducted to detect heterogeneity and pleiotropy by Cochran's Q test, MR-Egger test, MR-PRESSO global test, and "leave-one-out" analysis.

RESULTS

There were potential causal relationships between several mitochondrial proteins and AA/AD. Specifically, the iron-sulfur cluster assembly enzyme ISCU (OR = 1.165, 95% CI: 1.051-1.291, P = 0.004) and NFU1 iron-sulfur cluster scaffold homolog (OR = 1.184, 95% CI: 1.056-1.329, P = 0.004) were identified as potential risk factors for AA; whereas the 39 S ribosomal protein L14 (OR = 0.868, 95% CI: 0.764-0.987, P = 0.031) was found to be a protective factor for AA. Furthermore, 39 S ribosomal protein L33 (OR = 1.134, 95% CI: 1.010-1.274, P = 0.033) and cytochrome C oxidase subunit 5B (OR = 1.330, 95% CI: 1.037-1.706, P = 0.025) were associated with increased risks of AD; whereas the 39 S ribosomal protein L52 (OR = 0.736, 95% CI: 0.550-0.984, P = 0.038) and mitochondrial ubiquitin ligase activator of NFKB 1 (OR = 0.806, 95% CI: 0.656-0.989, P = 0.039) were identified as potential protective factors for AD. Sensitivity analysis confirmed the stability of the results.

CONCLUSIONS

This study identified potential genetic associations between mitochondrial proteins and AA/AD. Targeting these mitochondrial proteins may help prevent the occurrence of AA/AD.

Restoring Vascular Smooth Muscle Cell Mitochondrial Function Attenuates Abdominal Aortic Aneurysm in Mice

BACKGROUND

Abdominal aortic aneurysm (AAA) is a complex vascular pathology without pharmaceutical interventions. This study aimed to evaluate whether restoring vascular smooth muscle cell (VSMC) mitochondrial function could prevent AAA development.

METHODS

Ang II (angiotensin II)-induced AAA was established in Ldlr-deficient mice, and the gene expression profiles in abdominal aortic tissues exhibiting varying degrees of severity were analyzed. Synthetic high-density lipoprotein (sHDL) formulated with Apoa1 mimetic peptide and phospholipids was evaluated for the protective effects on VSMC mitochondria. The therapeutic efficacy of sHDL was further investigated in Ang II-infusion and PPE (porcine pancreatic elastase)-induced AAA models.

RESULTS

VSMC mitochondrial damage intensified gradually during AAA development, which was confirmed in distinct AAA animal models and human tissues. sHDL accumulated in the aneurysmatic lesions and restored mitochondrial DNA levels and the expression of genes related to oxidative phosphorylation following Ang II infusion. In mouse primary VSMCs, sHDL maintained mitochondrial homeostasis by suppressing the upregulation of DRP1 (dynamin-related protein 1), a protein involved in mitochondrial fission, reducing the generation of reactive oxygen species, preventing the loss of mitochondrial membrane potential, and preserving mitochondrial respiratory capacity. Administration of sHDL decreased Ang II-induced AAA incidence (control versus treatment, 76% versus 40%; P<0.05) and maximum aortic diameters. The protective effects of sHDL were further validated in the PPE model, with reductions observed in maximum aortic diameters and aortic mitochondrial DNA loss. Post-Ang II infusion, administration of sHDL improved VSMC mitochondrial function and suppressed aneurysm growth in Apoe-deficient mice. Human AAA is characterized by mitochondrial dysfunction, and liver-derived HDL (high-density lipoprotein) components play a pivotal role in regulating gene expression in aortic tissues.

CONCLUSIONS

VSMC mitochondrial damage is a pivotal factor in the development of AAA. The utilization of sHDL nanoparticles represents a promising novel therapeutic approach for AAA, aimed at restoring VSMC mitochondrial function.

Agathis dammara Extract and its Monomer Araucarone Attenuate Abdominal Aortic Aneurysm in Mice

BACKGROUND

Abdominal aortic aneurysm (AAA) is a chronic vascular disease wherein the inflammation of vascular smooth muscle cells (VSMCs) plays a pivotal role in its development. Effectively mitigating AAA involves inhibiting VSMC inflammation. Agathis dammara (Lamb.) Rich, recognized for its robust anti-inflammatory and antioxidant attributes, has been employed as a traditional medicinal resource. Nonetheless, there is a dearth of information regarding the potential of Agathis dammara extract (AD) in attenuating AAA, specifically by diminishing vascular inflammation, notably VSMC inflammation. Furthermore, the active constituents of AD necessitate identification.

AIM OF THE STUDY

This study sought to ascertain the efficacy of AD in reducing AAA, evaluate its impact on VSMC inflammation, and elucidate whether the monomer araucarone (AO) in AD acts as an active component against AAA.

MATERIALS AND METHODS

The extraction of AD was conducted and subjected to analysis through High-Performance Liquid Chromatography (HPLC) and mass spectrometry. The isolation of the AO monomer followed, involving the determination of its content and purity. Subsequently, the effects of AD and AO on VSMC inflammation were assessed in vitro, encompassing an examination of inflammatory factors such as IL-6 and IL-18, as well as the activation of matrix metalloproteinase 9 (MMP9) in tumor necrosis factor-alpha (TNF-α)-stimulated VSMCs. To explore the inhibitory effects of AD/AO on AAA, C57BL/6J male mice were subjected to oral gavage (100 mg/kg) or intraperitoneal injection (50 mg/kg) of AD and AO in a porcine pancreatic elastase (PPE)-induced AAA model (14 days). This facilitated the observation of abdominal aorta dilatation, remodeling, elastic fiber disruption, and macrophage infiltration. Additionally, a three-day PPE mouse model was utilized to assess the effects of AD and AO (administered at 100 mg/kg via gavage) on acute inflammation and MMP9 expression in blood vessels. The mechanism by which AD/AO suppresses the inflammatory response was probed through the examination of NF-κB/NLRP3 pathway activation in VSMCs and aortas.

RESULTS

Liquid Chromatography-Mass Spectrometry (LC-MS) revealed that AO constituted 15.36% of AD's content, with a purity of 96%. Subsequent pharmacological investigations of AO were conducted in parallel with AD. Both AD and AO exhibited the ability to inhibit TNF-α-induced VSMC inflammation and MMP production in vitro. Furthermore, both substances effectively prevented PPE-induced AAA in mice, whether administered through gavage or intraperitoneal injection, evidenced by decreased vascular diameter dilation, disruption of elastin fiber layers, and infiltration of inflammatory cells. In the three-day PPE mouse model, AD and AO mitigated the heightened expression of inflammatory factors and the elevated expression of MMP9 induced by PPE. The activation of the NF-κB/NLRP3 pathway in both VSMCs and aortas was significantly suppressed by treatment with AD or AO.

CONCLUSIONS

Through suppressing NF-κB/NLRP3 pathway activation, AD effectively mitigates the inflammatory response in VSMCs, mitigates inflammation in aortas, prevents extracellular matrix degradation, and consequently impedes the progression of AAA. AO emerges as one of the active compounds in AD responsible for inhibiting VSMC inflammation and inhibiting AAA development.

Lipidomic insights on abdominal aortic aneurysm and peripheral arterial disease

Abdominal aortic aneurysm (AAA) and peripheral arterial disease (PAD) are two cardiovascular diseases associated with considerable morbidity, mortality and quality of life impairment. As they are multifactorial diseases, several factors contribute to their pathogenesis, including oxidative stress and lipid peroxidation, and these may have key roles in the development of these pathologies. Alterations of the lipid metabolism and lipid profile have been reported in cardiovascular diseases but to a lesser extent in AAA and PAD. Modifications in the profile of some molecular lipid species, in particular, native phospholipid and triglyceride species were mainly reported for AAA, while alterations in the fatty acid profile were noticed in the case of PAD. Oxidized phospholipids were also reported for AAA. Although AAA and PAD have a common atherosclerotic root, lipidomics demonstrates the existence of distinct lipid. Lipidomic research regarding AAA and PAD is still scarce and should be set in motion to increase the knowledge on the lipid changes that occur in these diseases, contributing not only to the discovery of new biomarkers for diagnosis and prognosis assessment but also to tailor precision medicine in the clinical field.

Fibroblast Activation Protein Acts as a Biomarker for Monitoring ECM Remodeling During Aortic Aneurysm via 68Ga-FAPI-04 PET Imaging

Traditional imaging modalities used to monitor the diameter of aortic aneurysms (AAs) often fail to follow pathological progression. Fibroblast activation protein (FAP), a key regulator of extracellular matrix (ECM) remodeling, plays a pivotal role in aortic disease. However, its expression in the aortic wall during aneurysm progression and its potential correlation with disease severity remains unexplored. Here, utilizing histology the levels of FAP are higher in the aortic wall of patients with AA compared to healthy controls. In three distinct animal models of AA, a progressive increase in FAP expression, coincides with the advancement of ECM remodeling. Notably, the levels of 68Ga-FAPI-04 uptake in a rabbit model of abdominal AA (AAA) is positively correlated with aortic dilation (r = 0.84, p < 0.01), and the histological examination further confirmed that regions of high 68Ga-FAPI-04 uptake exhibited both increased FAP expression and more severe pathological changes. The 68Ga-FAPI-04 imaging in AA patients showed that the radiotracer specifically accumulated in the aortic walls of persistently dilated AA. These findings suggest that 68Ga-FAPI-04 positron emission tomographic (PET) imaging, by visualizing FAP localization, allows for a non-invasive approach to potentially monitor ECM remodeling during the AA progression.

GlycoRNA-rich, neutrophil membrane-coated, siMT1-loaded nanoparticles mitigate abdominal aortic aneurysm progression by inhibiting the formation of neutrophil extracellular traps

Abdominal aortic aneurysm (AAA) is a life-threatening vascular condition. Currently, there are no clinically available pharmacological interventions that can stop the progression of AAA, primarily due to the incomplete understanding of its pathogenesis and the absence of effective drug delivery systems. The present study aimed to develop a targeted therapy for AAA through a nanomedicine approach involving site-specific regulation of neutrophil extracellular trap (NET)-related pathological vascular remodeling. We found that metallothionein 1 (MT1) was upregulated in AAA lesions in both humans and mice. MT1 also facilitated the formation of NETs and subsequently induced phenotypic transformation and apoptosis in vascular smooth muscle cells. Additional in vivo studies revealed that the glycoRNA-rich membranes coated siMT1-loaded poly(lactic-co-glycolic acid) (PLGA)-polyethylene glycol (PEG) nanoparticles (GlycoRNA-NP-siMT1) effectively delivered siMT1 to AAA lesions, thereby inhibiting abdominal aortic dilation. Mechanistically, GlycoRNA-NP-siMT1 mitigated pathological remodeling of the abdominal aorta by reducing neutrophil infiltration and inhibiting the formation of NETs. Our study indicates that MT1 facilitates the progression of AAA by modulating the formation of NETs. Furthermore, GlycoRNA-NP-siMT1 show an inhibitory effect on AAA progression through a dual mechanism: they competitively inhibit neutrophil infiltration and release siMT1, which subsequently suppresses NET formation.

Effective Hydrogel Vascular Patch Dual-Loaded with Cycloastragenol Nanostructured Lipid Carriers and Doxycycline for Repairing Extravascular Injury in Abdominal Aortic Aneurysm

Endovascular aneurysm repair (EVAR) plays a crucial role in the treatment of abdominal aortic aneurysm (AAA) in the clinic, but the aneurysm remains in the patient's body after surgery, continuing to pose a risk of progression. Cycloastragenol (CAG) is proven to be an effective anti-AAA drug, and its vascular protective effects can be further improved when the hydrophobic CAG is encapsulated into nano-sized formulations to enhance its bioavailability. In this context, this study developed an extravascular patch hydrogel loaded with CAG nanostructured lipid carriers and a hydrophilic drug of doxycycline hydrochloride (DOX). The extravascular patch delivered onto the mouse abdominal aortas can promote local permeation of hydrophilic/hydrophobic drugs at the vessel sites and provide effective vascular protection against AAA injury induced by elastase. This study introduces a novel and promising approach for AAA treatment, which can serve as a supplementary strategy after EVAR surgery.

Functional anti-inflammatory mesoporous silica nanoplatform for Synergistic and Targeted abdominal aortic aneurysm treatment

Abdominal aortic aneurysm (AAA) is a chronic inflammation-driven disease characterized by aortic wall destruction and expansion, leading to high morbidity and mortality. However, previous drug treatments for its common risk factors have not achieved favorable results, and the early prevention and treatment is still the main clinical dilemma. Anti-inflammation therapy is a promising therapeutical method targeting its pathogenesis mechanism, but it has not been explored in depth. Herein, interleukin-1 receptor antagonist-loaded manganese-doped mesoporous silica nanoparticles (IL-1Ra@MMSN) were designed and synthesized to target macrophage-mediated chronic aortic inflammation for AAA treatment. IL-1Ra@MMSN showed high IL-1Ra-loading efficiency, great stability and pH-responsive drug-releasing property. IL-1Ra@MMSN specially phagocytosed by macrophages can protect against oxidative stress injury and promoted the M2 polarization via transforming growth factor-β (TGF-β) signaling in vitro. Furthermore, IL-1Ra@MMSN exhibited good lesion targeting ability, hemocompatibility and biocompatibility in angiotensin II-induced murine AAA model. In vivo experiments also confirmed the excellent treatment efficacy in reducing AAA formation and progression via protecting aortic wall integrity and promoting anti-inflammatory microenvironment. Taken together, the current study demonstrated that IL-1Ra@MMSN is a promising nanoplatform for early intervention of AAA, which provides a novel treatment strategy based on anti-inflammatory immune regulation.

Targeting GPX4 alleviates ferroptosis and retards abdominal aortic aneurysm formation

Abdominal aortic aneurysm (AAA) is a potentially fatal cardiovascular disease, closely related to inflammation and loss of vascular smooth muscle cells (VSMCs). Ferroptosis is an iron-dependent cell death associated with peroxidation of lipids. However, the direct role of glutathione peroxidase 4 (GPX4) itself determined ferroptosis in the course of AAA pathogenesis remains unknown. Here, we reported that ferroptosis was triggered in human AAA, elastase- and angiotensin II (Ang II)-induced mouse AAA, and Ang II-incubated VSMCs. Inhibition of ferroptosis via global genetic overexpression of GPX4, a critical anti-ferroptosis molecule, markedly prevented both vascular remodeling and inflammatory response. Mechanistically, GPX4 changed the migration and activation of macrophages/monocytes in AAA tissues in mice. Experiments in vitro demonstrated that overexpression of GPX4 prevented the JAK1/STAT3 signaling activation in VSMCs induced by IL-6, production of pro-inflammatory macrophages. Finally, the role of ferroptosis was confirmed on an Ang II-induced mice AAA model. These results emphasized the significance of ferroptosis in AAA, and provided novel insights that therapy focusing on GPX4 might be a promising strategy for treatment of AAA in the clinic.

Hypertriglyceridemia as a Key Contributor to Abdominal Aortic Aneurysm Development and Rupture: Insights from Genetic and Experimental Models

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease without effective medications. This study integrated genetic, proteomic, and metabolomic data to identify causation between increased triglyceride (TG)-rich lipoproteins and AAA risk. Three hypertriglyceridemia mouse models were employed to test the hypothesis that increased plasma TG concentrations accelerate AAA development and rupture. In the angiotensin II-infusion AAA model, most Lpl -deficient mice with severely high plasma TG concentrations died of aortic rupture. Consistently, Apoa5 -deficient mice with moderately increased TG concentrations had accelerated AAA development, while human APOC3 transgenic mice with dramatically increased TG concentrations exhibited aortic dissection and rupture. Increased TG concentrations and palmitate inhibited lysyl oxidase maturation. Locally overexpressing lysyl oxidase eliminated the impact of high TG on AAA formation in human APOC3 transgenic mice. Administration of antisense oligonucleotide targeting Angptl3 profoundly inhibited AAA progression in human APOC3 transgenic mice and Apoe -deficient mice. These results indicate that hypertriglyceridemia is a key contributor to AAA pathogenesis, highlighting the importance of triglyceride-rich lipoprotein management in treating AAA.

Clinical Perspective

What Is New?: This study integrates genetic, proteomic, and metabolomic data to identify causation between increased triglyceride (TG)-rich lipoproteins and AAA risk.TG concentrations influence AAA formation and severity in a dose-dependent manner, potentially by inhibiting lysyl oxidase maturation and extracellular matrix assembly. Administration of antisense oligonucleotide targeting Angptl3 profoundly inhibites AAA progression in human APOC3 transgenic mice and Apoe -deficient mice by lowering TG concentrations. What Are the Clinical Implications?: These findings underscore triglyceride-rich lipoprotein management as a promising therapeutic strategy for AAA treatment.Antisense oligonucleotide therapy targeting liver ANGPTL3 holds potential as a therapeutic approach to reduce AAA risk.

SAMD4A inhibits abdominal aortic aneurysm development and VSMC phenotypic transformation through targeting KDM2B

INTRODUCTION

Abdominal aortic aneurysm (AAA) is a fatal vascular disease without effective drug treatments. Pathological vascular smooth muscle cell (VSMC) phenotypic transformation is the underlying cause of AAA. However, the underlying mechanism has not been fully elucidated.

OBJECTIVE

We aimed to determine whether the RNA binding protein SAMD4A suppresses VSMC phenotype transformation and inhibits AAA formation.

METHODS

Single-cell RNA sequencing (scRNA-seq) was conducted to reveal smooth muscle cell phenotypic heterogeneity and RNA-binding protein dysregulation during AAA formation. A pancreatic elastase (PPE)-induced mouse AAA model was generated to confirm the function of SAMD4A in vivo. RNA-seq combined with RNA immunoprecipitation (RIP) sequencing and chromatin immunoprecipitation (ChIP)-qPCR was used for mechanistic exploration.

RESULTS

We identified 3 smooth muscle cell subtypes, and demonstrated their transformation from contractile to inflammatory-like VSMCs during AAA formation. SAMD4A expression was increased in contractile VSMCs and significantly reduced in AAAs. The results of functional experiments revealed that VSMC-specific knockout of SAMD4A exacerbated PPE-induced AAA formation, whereas VSMC knock-in attenuated AAA formation. SAMD4A regulated VSMC contraction by binding to KDM2B. Further in vivo studies revealed that overexpression of KDM2B abolished the protective effect of SAMD4A in AAA. ChIP-qPCR demonstrated that KDM2B suppressed the transcription of VSMC contractile markers by binding to their promoters and reducing H3K4me3 and H3K36me2 levels.

CONCLUSIONS

SAMD4A inhibits AAA development and VSMC phenotypic transformation by targeting KDM2B. This work highlights the potential of SAMD4A as a new therapeutic option to prevent AAA formation.

Protein Drug Targets for Abdominal Aortic Aneurysm and Proteomic Associations Between Modifiable Risk Factors and Abdominal Aortic Aneurysm

BACKGROUND

Abdominal aortic aneurysm (AAA) is a severe aortic disease for which no pharmacological interventions have yet been developed. This investigation focused on identifying protein-based therapeutic targets and assessing how proteins mediate the interplay between modifiable risk factors and AAA development.

METHODS

Causal inferences between plasma proteins and AAA were drawn using 2-sample Mendelian randomization, followed by comprehensive sensitivity testing, colocalization, and replication efforts. Further analyses included database interrogation, single-cell RNA data analysis, enrichment analysis, protein-protein interaction networks, and immunohistochemistry to map the tissue-specific expression of these proteins, their expression within AAA tissues, and their biological roles. Mediation Mendelian randomization was employed to evaluate the mediating effects of AAA-related proteins on the associations between AAA and 3 risk factors: hypertension, smoking, and obesity.

RESULTS

A total of 43 proteins were identified as having causal links to AAA. Colocalization analysis pinpointed 13 proteins with strong evidence of colocalization with AAA. Of these, the causal involvement of 10 proteins was substantiated by external validation data. Consistent evidence for PCSK9 (proprotein convertase subtilisin/kexin type 9), IL6R (interleukin-6R), ECM1 (extracellular matrix protein 1), and ANGPTL4 (angiopoietin-related protein 4) was further validated through tissue immunohistochemistry and blood data. Moreover, Mendelian randomization analysis identified 10 proteins as mediators of the influence of hypertension, smoking, and obesity on AAA development.

CONCLUSIONS

This analysis identifies 4 proteins (PCSK9, IL6R, ECM1, and ANGPTL4) as high-priority therapeutic targets for AAA and emphasizes the intermediary role of plasma proteins in linking hypertension, smoking, obesity, and AAA. Further investigations are needed to clarify the specific roles of these proteins in AAA pathology.

Exploring Disparities in Atherosclerosis Comorbidity with Aortic Aneurysm

Aortic aneurysm (AA) and atherosclerosis (AS) of various vascular beds are asymptomatic for a long time and are relatively common pathological conditions that lead to life-threatening and disabling complications. In this review, we discuss the current understanding of the high variation in direct and inverse comorbidity of AA and AS as presented in scientific publications. Estimates of AA and AS comorbidity depend on several factors, such as the location of AA (ascending or descending thoracic aorta or abdominal aorta), familial or sporadic cases of AA, syndromic forms of AA, and/or aortic valve pathology (bicuspid aortic valve [BAV]). To identify the causes of the comorbidity of AA and AS, it is important to consider and characterise many factors in detail. These factors include clinical characteristics of the patients included in a study (age, sex) and risk factors (mainly the presence of monogenic forms and BAV, hypertension, hypercholesterolaemia, diabetes mellitus, and cigarette smoking). Additionally, it is essential to consider characteristics of the disease course and the nature of multimorbidity and to take into account pathologies not only of the cardiovascular system but also of other organ systems, with special attention to metabolic and endocrine disorders.

Sexual dimorphism in aortic aneurysm: A review of the contributions of sex hormones and sex chromosomes

Aortic aneurysm is a common cardiovascular disease. Over time, the disease damages the structural and functional integrity of the aorta, causing it to abnormally expand and potentially rupture, which can be fatal. Sex differences are evident in the disease, with men experiencing an earlier onset and higher incidence. However, women may face a worse prognosis and a higher risk of rupture. While there are some studies on the cellular and molecular mechanisms of aneurysm formation, it remains unclear how sex factors contribute to sexual dimorphism. Therefore, this review aims to summarize the role of sex in the occurrence of aortic aneurysms, offering valuable insights for disease prevention and the development of appropriate treatment options.

Inhibition of ATP-citrate lyase by bempedoic acid protects against abdominal aortic aneurysm formation in mice

Abdominal aortic aneurysm (AAA) is a prevalent degenerative disease characterized by an exacerbated inflammation and destructive vascular remodeling. Unfortunately, effective pharmacological tools for the treatment of this disease remain a challenge. ATP-citrate lyase (ACLY), the primary enzyme responsible for acetyl-CoA biosynthesis, is a key regulator of inflammatory signaling in macrophages and lymphocytes. Here, we found increased levels of the active (phosphorylated) form of ACLY (p-ACLY) in the inflammatory infiltrate of AAA from patients and in aneurysmal lesions from angiotensin II (Ang II)-infused apolipoprotein E-deficient mice (ApoE-/-). Furthermore, plasma ACLY levels positively correlates with IL6 and IFNγ levels in patients with AAA, while inflammatory stimuli strongly upregulated ACLY expression in macrophages and Jurkat cells. The administration of the ACLY inhibitor bempedoic acid (BemA) protected against Ang II-induced AAA formation in ApoE-/- mice, limiting the progression of aortic dilatation and reducing mortality due to aortic rupture. BMS-303141, another ACLY inhibitor, also ameliorated AAA formation, although to a lesser extent. BemA attenuated vascular remodeling and the disorganization and rupture of elastic fibers induced by Ang II, as well as vascular inflammation, decreasing the recruitment of macrophages (CD68 +) and neutrophils (Ly-6G+) into the aortic wall. Moreover, BemA shifted splenic monocytes toward a functionally anti-inflammatory phenotype, and increased the percentage of CD4+CD69+ cells. Taken together, these results support the contribution of ACLY to AAA and point to BemA as a promising tool to be considered for future clinical trials addressing the management of this disease which is quite often associated with disorders of lipoprotein metabolism.

Metformin Improves the Function of Abdominal Aortic Aneurysm Patient-Derived Aortic Smooth Muscle Cells

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is a cardiovascular risk factor. Paradoxically, a decreased risk of abdominal aortic aneurysm (AAA) presence and growth rate is described among patients with T2DM, associated with metformin use. This study aimed to investigate the effect of metformin on AAA patient-derived aortic smooth muscle cell (SMC) function.

METHODS

Aortic biopsies were obtained from patients with AAA (n = 21) and controls (n = 17) during surgery. The SMCs of non-pathological aortic controls, non-diabetic patients with AAA, and diabetic patients with AAA were cultured from explants and treated with or without metformin. The SMC contractility was measured upon ionomycin stimulation, as well as metabolic activity, proliferation, and migration. mRNA and protein expression of markers for contraction, metabolic activity, proliferation, and inflammation were measured.

RESULTS

mRNA expression of KLF4 and GYS1, genes involved in metabolic activity, differed between SMCs from non-diabetic and diabetic patients with AAA before metformin stimulation (p < .041). However, the effect of metformin on the various SMC functions was similar between non-diabetic and diabetic patients with AAA. Upon stimulation, metformin increased the contractility of AAA patient SMCs (p = .001). mRNA expression of smoothelin, a marker for the contractile phenotype, increased in SMCs of patients with AAA after treatment with metformin (p = .006). An increase in metabolic activity (p < .001) and a decrease in proliferation (p < .001) and migration were found in the SMCs of controls and patients with AAA with metformin. Increased mRNA expression of PPARγ, a nuclear receptor involved in mitochondrial biogenesis (p < .009), and a decrease in gene expression of Ki-67, a marker for proliferation (p < .005), were observed. Gene expression of inflammation markers MCP-1 and IL-6, and protein expression of NF-κB p65 decreased after treatment with metformin in patients with AAA.

CONCLUSION

This study found that metformin increases contractility and metabolic activity, and reduces proliferation, migration, and inflammation in aortic SMCs in vitro.

Dihydromyricetin mitigates abdominal aortic aneurysm via transcriptional and post-transcriptional regulation of heme oxygenase-1 in vascular smooth muscle cells

Abdominal aortic aneurysm (AAA) is a deadly condition of the aorta, carrying a significant risk of death upon rupture. Currently, there is a dearth of efficacious pharmaceutical interventions to impede the advancement of AAA and avert it from rupturing. Here, we investigated dihydromyricetin (DHM), one of the predominant bioactive flavonoids in Ampelopsis grossedentata (A. grossedentata), as a potential agent for inhibiting AAA. DHM effectively blocked the formation of AAA in angiotensin II-infused apolipoprotein E-deficient (ApoE-/-) mice. A combination of network pharmacology and whole transcriptome sequencing analysis revealed that DHM's anti-AAA action is linked to heme oxygenase (HO)-1 (Hmox-1 for the rodent gene) and hypoxia-inducible factor (HIF)-1α in vascular smooth muscle cells (VSMCs). Remarkably, DHM caused a robust rise (∼10-fold) of HO-1 protein expression in VSMCs, thereby suppressing VSMC inflammation and oxidative stress and preserving the VSMC contractile phenotype. Intriguingly, the therapeutic effect of DHM on AAA was largely abrogated by VSMC-specific Hmox1 knockdown in mice. Mechanistically, on one hand, DHM increased the transcription of Hmox-1 by triggering the nuclear translocation and activation of HIF-1α, but not nuclear factor erythroid 2-related factor 2 (NRF2). On the other hand, molecular docking, combined with cellular thermal shift assay (CETSA), isothermal titration calorimetry (ITC), drug affinity responsive target stability (DARTS), co-immunoprecipitation (Co-IP), and site mutant experiments revealed that DHM bonded to HO-1 at Lys243 and prevented its degradation, thereby resulting in considerable HO-1 buildup. In summary, our findings suggest that naturally derived DHM has the capacity to markedly enhance HO-1 expression in VSMCs, which may hold promise as a therapeutic strategy for AAA.

Interferon stimulated gene 15 (ISG15) modulates phenotype of vascular smooth muscle cells and pathological vascular remodeling

INTRODUCTION

Inflammation is a major determinant of abdominal aortic aneurysms (AAA). Interferon stimulated gene 15 (ISG15) has a role in vascular remodelling in AAA. This study investigates the mechanisms whereby ISG15 might affect vascular remodeling and function.

METHODS

We used vascular smooth muscle cells (VSMC) from wild type (ISG15+/+) o ISG15 knockout (ISG15-/-) mice, aorta from ISG15+/+ and ISG15-/- mice infused with angiotensin II (1.44mg/kg/day, sc, 14 days), and human AAA. We also performed a model of recombinant ISG15 infusion (rISG15, sc, 100 and 500ng/day, 14 days) in mice.

RESULTS

In VSMC, ISG15 deficiency increased the expression of contractile (Acta2, Tagln) and synthetic (Fn1, Col1a2, Col3, Col4) markers and decreased the expression of the calcification marker Spp1. Ang II infusion changed the expression of phenotype markers differently in aorta from ISG15+/+ or ISG15-/- mice. ISG15 expression showed a negative correlation with expression of contractile markers (ACTA2, CNN1), and with COL3a1, in human samples from patients with AAA or with stenotic aorto-iliac pathology. rISG15 infusion induced hypotrophic vascular remodelling in mesenteric arteries without affecting vascular mechanics. Aorta of ISG15-/- mice contracted more to thromboxane A2 analogue U46619, compared to ISG15-/-mice. Both aorta and mesenteric arteries from rISG15-treated mice showed less contractility than control mice.

CONCLUSIONS

ISG15 participates in pathological vascular remodeling probably by modulating VSMC phenotype. These changes could also impact in the vascular function.

WTAP-mediated m6A modification on BASP1 mRNA contributes to ferroptosis in AAA

BACKGROUND

Abdominal aortic aneurysm (AAA) is a common aneurysm that is often associated with atherosclerosis and can lead to artery rupture and death. Brain abundant membrane attached signal protein 1 (BASP1) is related to a variety of pathophysiological processes, but its role in AAA has not been reported.

METHODS

Real-time quantitative polymerase chain reaction (qRT-PCR) and western blot were used to detect the expressions of BASP1 and Wilms' tumor 1-associated protein (WTAP). Angiotensin-II (Ang-II) was employed for inducing AAA models in vitro to explore the effects and mechanism of BASP1 in AAA. Cell viability, apoptosis, oxidative stress level, and Fe2+ level were measured by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide (MTT), flow cytometry, and various kits, respectively. In terms of mechanism, the methylated RNA immunoprecipitation (MeRIP)-qPCR, the dual luciferase reporter assay, and the cytochrome experiments were utilized to evaluate the relationship between BASP1 and WTAP.

RESULTS

A highly expressed level of BASP1 was observed in aortic tissues of AAA patients and Ang-II could induce AAA models by treating vascular smooth muscle cells (VSMCs). In cellular function, BASP1 knockdown impaired AAA and ferroptosis resulted from Ang-II. Mechanically, WTAP mediated the N6-methyladenosine (m6A) modification and mRNA stability of BASP1. Meanwhile, WTAP was highly expressed in AAA tissues of patients and the effects of WTAP silence in AAA and ferroptosis were diminished by up-regulated BASP1.

CONCLUSION

WTAP promotes cell viability and inhibits apoptosis and ferroptosis resulted from Ang-II in VSMCs by mediating the m6A level of BASP1.

U-shaped association between plasma cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) levels and myocardial infarction

BACKGROUND

The cyclic guanosine monophosphate-adenosine monophosphate synthase-stimulator of interferon genes (cGAS-STING) signaling pathway is closely associated with myocardial infarction (MI). Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) is a key component of this pathway; however, there is currently a lack of clinical evidence linking plasma cGAMP levels to MI.

METHODS

This study utilized clinical data from 270 patients diagnosed with coronary heart disease (CHD) at the Second Xiangya Hospital of Central South University. The outcomes included ST-segment elevation and non-ST-segment elevation MI. Univariate and multivariate logistic regression models were used to explore the relationships between plasma cGAMP levels and MI, while restricted cubic spline (RCS) using logistic regression to explore the dose-response relationship.

RESULTS

Among the 270 patients, the mean plasma cGAMP level was 1352.58 ± 106.02 ng/L and 89 (32.96%) patients were diagnosed with MI. The RCS curves indicated a U-shape association between the cGAMP levels and MI; the risk of MI was negatively correlated with the cGAMP until it hit bottoms at 1352 ng/L. When the cGAMP level exceeded 1352 ng/L, the risk of MI increased significantly (adjusted OR, 1.02; 95% CI: 1.01-1.03). When considering cGAMP as a categorical variable, patients in Tertile 1 and Tertile 3 had a 167% (adjusted OR: 2.67, 95% CI: 1.23-5.78) and 155% (adjusted OR: 2.55, 95% CI: 1.17-5.55) higher risk of MI compared to those in Tertile 2, respectively. These results were consistent across subgroup analyses, notably, a significant interaction by age category was observed in patients with cGAMP ≥ 1352 ng/L, where the positive association was pronounced in the elderly.

CONCLUSIONS

A U-shaped association exists between cGAMP and MI in the CHD population, with a cutoff point at the cGAMP of 1352 ng/L. Both excessively high and low cGAMP levels are associated with an increased risk of MI, particularly among the elderly with cGAMP ≥ 1352 ng/L. This is the first clinical evidence of the cGAS-cGAMP-STING pathway in metabolic cardiovascular diseases.

CLINICALTRIALS

GOV IDENTIFIER

NCT03363035 (Registration date: 2018-01-15).

Genetic association between inflammatory factors and abdominal aortic aneurysm: Insights from a genome-wide association study

BACKGROUND

Abdominal aortic aneurysm (AAA) is a fatal vascular disorder. The current primary treatment for AAA remains restricted to surgical intervention during advanced stages of the disease, with no efficacious pharmaceutical options available for early-stage AAA patients. Inflammation is known to play a substantial role in the development of AAA, with various inflammatory factors implicated in its pathogenesis. However, conflicting findings have been reported in studies investigating the roles of these inflammatory factors in AAA, making it challenging to establish definitive causal relationships between inflammatory factors and AAA.

METHODS

The research conducted a bidirectional Mendelian randomization (MR) study using genetic variants. Inflammatory factors were obtained from a genome-wide association study (GWAS), while AAA were sourced from the FinnGen consortium. The primary method employed was inverse-variance weighted (IVW), with MR-Egger, weighted median, and MR-PRESSO approaches used as supplementary analyses.

RESULTS

According to the IVW method, hepatocyte growth factor (HGF), matrix metalloproteinase-7 (MMP-7), MMP-12, and NF-kappa-B essential modulator (NEMO/ IKKγ) were associated with a potential increased risk of AAA, while platelet-derived growth factor BB (PDGFbb), interleukin-4 (IL-4), IL-12p70, IL-10, IL-6Rα, and myeloperoxidase (MPO) were associated with a potential decreased risk of AAA. In the reverse MR analysis, no causal relationship was observed between AAA and any of the inflammatory factors.

CONCLUSIONS

This study provides evidence supporting a causal relationship between inflammatory factors and AAA. It suggests that targeting and modulating these specific inflammatory factors may serve as a potential approach for the prevention and noninvasive treatment of AAA.

Developing Trustworthy Artificial Intelligence Models to Predict Vascular Disease Progression: the VASCUL-AID-RETRO Study Protocol

INTRODUCTION

Abdominal aortic aneurysms (AAAs) and peripheral artery disease (PAD) are two vascular diseases with a significant risk of major adverse cardiovascular events and mortality. A challenge in current disease management is the unpredictable disease progression in individual patients. The VASCUL-AID-RETRO study aims to develop trustworthy multimodal predictive artificial intelligence (AI) models for multiple tasks including risk stratification of disease progression and cardiovascular events in patients with AAA and PAD.

METHODS

The VASCUL-AID-RETRO study will collect data from 5000 AAA and 6000 PAD patients across multiple European centers of the VASCUL-AID consortium using electronic health records from 2015 to 2024. This retrospectively-collected data will be enriched with additional data from existing biobanks and registries. Multimodal data, including clinical records, radiological imaging, proteomics, and genomics, will be collected to develop AI models predicting disease progression and cardiovascular risks. This will be done while integrating the international ethics guidelines and legal standards for trustworthy AI, to ensure a socially-responsible data integration and analysis.

PROPOSED ANALYSES

A consensus-based variable list of clinical parameters and core outcome set for both diseases will be developed through meetings with key opinion leaders. Blood, plasma, and tissue samples from existing biobanks will be analyzed for proteomic and genomic variations. AI models will be trained on segmented AAA and PAD artery geometries for estimation of hemodynamic parameters to quantify disease progression. Initially, risk prediction models will be developed for each modality separately, and subsequently, all data will be combined to be used as input to multimodal prediction models. During all processes, data security, data quality, and ethical guidelines and legal standards will be carefully considered. As a next step, the developed models will be further adjusted with prospective data and internally validated in a prospective cohort (VASCUL-AID-PRO study).

CONCLUSION

The VASCUL-AID-RETRO study will utilize advanced AI techniques and integrate clinical, imaging, and multi-omics data to predict AAA and PAD progression and cardiovascular events.

CLINICAL TRIAL REGISTRATION

The VASCUL-AID-RETRO study is registered at www.clinicaltrials.gov under the identification number NCT06206369.

CLINICAL IMPACT

The VASCUL-AID-RETRO study aims to improve clinical practice of vascular surgery by developing artificial intelligence-driven multimodal predictive models for patients with abdominal aortic aneurysms or peripheral artery disease, enhancing personalized medicine. By integrating comprehensive data sets including clinical, imaging, and multi-omics data, these models have the potential to provide accurate risk stratification for disease progression and cardiovascular events. An innovation lies in the extensive European data set in combination with multimodal analyses approaches, which enables the development of advanced models to facilitate better understanding of disease mechanisms and progression. For clinicians, this means that more precise, individualized treatment plans can be established, ultimately aiming to improve patient outcomes.

Dimethyl fumarate is repurposed to ameliorate aortic aneurysm and dissection in mice

Aortic aneurysm and dissection pose fatal threats but no effective drug therapies are available. Previous work has been directed to reduce risk factors or target key pathological events, but none of the translational efforts succeeds. Here, we attempt to repurpose dimethyl fumarate (DMF), an FDA-approved immunomodulatory drug for multiple sclerosis, for the treatment of aortic aneurysm and dissection. In three preclinical mouse models of abdominal aortic aneurysm (porcine pancreatic elastase perfusion or CaCl2 incubation) and thoracic aortic aneurysm and dissection (β-Aminopropionitrile feeding), DMF invariably protected mice from aneurysm growth, aortic dissection, rupture and death. Histological H&E and EVG staining demonstrated aortic architecture-preserving effects of DMF. Through transcriptome profiling and the connectivity map (CMap), we showed that DMF restored SRC-FAK signaling in aortic smooth muscle cells and increased collagen I turnover in the tunica media. Our work suggests the potential of DMF being repurposed for aortic aneurysm and dissection, and highlights the importance of SRC-FAK signaling in aortic homeostasis.

CIDEC/FSP27 exacerbates obesity-related abdominal aortic aneurysm by promoting perivascular adipose tissue inflammation

Abdominal aortic aneurysm (AAA) is strongly correlated with obesity, partially due to the abnormal expansion of abdominal perivascular adipose tissue (PVAT). Cell death-inducing DNA fragmentation factor-like effector C (CIDEC), also known as fat-specific protein 27 (FSP27) in rodents, is specifically expressed in adipose tissue where it mediates lipid droplet fusion and adipose tissue expansion. Whether and how CIDEC/FSP27 plays a role in AAA pathology remains elusive. Here, we show that FSP27 exacerbates obesity and angiotensin Ⅱ (Ang Ⅱ)-induced AAA progression. FSP27 deficiency in mice inhibited high-fat diet-induced PVAT expansion and inflammation. Both global and adipose tissue-specific FSP27 ablation significantly decreased obesity-related AAA incidence. Deficiency of FSP27 in adipocytes abrogated matrix metalloproteinase-12 (MMP12) expression in aortic tissues. Infiltrated macrophages, which partially colocalize with MMP12, were significantly decreased in the FSP27-deficient aorta. Mechanistically, knockdown of Fsp27 in 3T3-L1 adipocytes inhibited C-C motif chemokine ligand 2 (CCL2) expression and secretion through a c-Jun N-terminal kinase (JNK)-dependent pathway, thereby leading to reduced induction of macrophage migration, while Cidec overexpression rescued this effect. Overall, our study demonstrates that CIDEC/FSP27 in adipose tissue contributes to obesity-related AAA formation, at least in part, by enhancing PVAT inflammation and macrophage infiltration, thus shedding light on its significance as a key regulator in the context of obesity-related AAA.

Myeloid Cell mPGES-1 Deletion Attenuates Calcium Phosphate-induced Abdominal Aortic Aneurysm in Male Mice

Microsomal PGE2 synthase (mPGES)-1 is the key enzyme responsible for synthesizing inflammatory prostaglandin E2 (PGE2). Our previous studies have shown that deletion mPGES-1 in myeloid cells hinders atherogenesis, suppresses vascular proliferative response to injury and enhances survival after myocardial infarction. Here we aimed to further explore the influence of myeloid cell mPGES-1 deletion in abdominal aortic aneurysm (AAA) formation. The AAA was triggered by applying 0.5 M calcium phosphate (CaPO4) to the infrarenal aorta of both myeloid mPGES-1 knockout (Mac-mPGES-1-KO) and their littermate control Mac-mPGES-1-WT mice. AAA induction was assessed by calculating the expansion of the infrarenal aortic diameter 4 weeks after CaPO4 application. The maximum diameters of the aortas were measured by morphometry and the mean maximal diameters were calculated. Paraffin sections of the infrarenal aortas were examined for morphological analysis and immunohistochemical staining. The results showed that myeloid cell mPGES-1 deletion significantly mitigated AAA formation, including reducing expansion of the infrarenal aorta, preventing elastic lamellar degradation, and decreasing aortic calcium deposition. Immunohistochemical staining further indicated that macrophage infiltration and matrix metalloproteinase 2 (MMP2) expression was attenuated in the Mac-mPGES-1-KO aortas. Consistently, in vitro experiments showed that expression of pro-inflammatory cytokines and MMPs was significantly reduced when mPGES-1 was lacking in the primary cultured peritoneal macrophages. These data altogether demonstrated that deletion of mPGES-1 in myeloid cells may attenuate AAA formation and targeting myeloid cell mPGES-1 could potentially offer an effective strategy for the treatment and prevention of vascular inflammatory diseases.

The TRPM7 chanzyme in smooth muscle cells drives abdominal aortic aneurysm in mice

Ionic signaling in smooth muscle cells (SMCs) is critical for vascular homeostasis. In this study, we untangled the role of the bifunctional TRPM7 channel kinase (chanzyme) in abdominal aortic aneurysm (AAA) pathogenesis. Comparing SMC-specific, macrophage-specific and endothelial cell-specific Trpm7 knockout, we revealed that SMC-specific Trpm7 deficiency protected mice from AAA in two distinct preclinical models of the disease. We showed that the TRPM7 channel activity increased the Ca2+ and Zn2+ influx and the Ca2+/calcineurin/CRTC2/CREB-dependent and Zn2+/MTF1-dependent Mmp2 transcription. Repurposing the clinical drug FTY720 to prevent and treat AAA resulted in improved aortic phenotypes through inhibition of TRPM7 channel activity. This study highlights the ionic mechanisms underlying AAA, identifies TRPM7 as a potential therapeutic target and suggests that blocking TRPM7 channels could be a viable strategy for treating AAA.

TRAF6 promotes abdominal aortic aneurysm development by activating macrophage pyroptosis via the NLRP3/Caspase1/GSDMD pathway

Abdominal aortic aneurysm represents a critical pathology of the aorta that currently lacks effective pharmacological interventions. TNF receptor-associated factor 6 (TRAF6) has been established to be involved in cardiovascular diseases such as atherosclerosis, hypertension, and heart failure. However, its role in abdominal aortic aneurysm (AAA) remains unclear. This study aimed to explore the role of TRAF6 on AAA formation and its underlying mechanisms. Single-cell RNA sequencing of human AAA tissues demonstrated that TRAF6 was significantly upregulated in aortic macrophages. Moreover, overexpression of TRAF6 promotes AAA formation in elastase-induced C57BL/6 mice, while TRAF6 pharmacological inhibition could attenuate AAA development. Consistently, inhibition of TRAF6 in macrophages through in vitro methods notably limits their pyroptosis, while also diminishing proinflammatory responses in these cells. Mechanistically, TRAF6 can modulate macrophage pyroptosis through the NLRP3/Caspase1/GSDMD signaling pathway. Our study highlights the crucial role of the TRAF6/NLRP3/Caspase1/GSDMD axis in macrophage pyroptosis and AAA, offering potential biomarkers and therapeutic targets for AAA.

Identifying abdominal aortic aneurysm size and presence using Natural Language Processing of radiology reports: a systematic review and meta-analysis

BACKGROUND AND AIM

Prior investigations of the natural history of abdominal aortic aneurysms (AAAs) have been constrained by small sample sizes or uneven assessments of aggregated data. Natural language processing (NLP) can significantly enhance the investigation and treatment of patients with AAAs by swiftly and effectively collecting imaging data from health records. This meta-analysis aimed to evaluate the efficacy of NLP techniques in reliably identifying the existence or absence of AAAs and measuring the maximal abdominal aortic diameter in extensive datasets of radiology study reports.

METHOD

The PubMed, Scopus, Web of Science, Embase, and Science Direct databases were searched until March 2024 to obtain pertinent papers. The RAYYAN intelligent tool for systematic reviews was utilized to screen the studies. The meta-analysis was conducted using STATA v18 software. Egger's test was employed to evaluate publication bias. The Newcastle Ottawa Scale was employed to assess the quality of the listed studies. A plot digitizer was employed to extract digital data.

RESULT

A total of 39,094 individuals with AAA were included in this analysis. Twenty-seven thousand three hundred twenty-six patients were male, and 11,383 were female. The mean age of the total participants was 73.1 ± 1.25 years. Analysis results for pooled estimation of performance variables such as: The sensitivity, specificity, precision, and accuracy of the implemented NLP model were analyzed as follows: 0.89(0.88-0.91), 0.88 (0.87-0.89), 0.92 (0.89-0.95), and 0.91 (0.89-0.93) respectively. The aneurysm diameter size difference reported in follow-up before and after NLP implementation in the included studies showed a 0.05 cm reduction in size, which was statistically significant.

CONCLUSION

NLP holds great potential for automating the detection of AAA size and presence in radiology reports, enhancing efficiency and scalability over manual review. However, challenges persist. Variability in report formats, terminology, and unstructured data can compromise accuracy. Additionally, NLP models rely on high-quality, annotated training datasets, which may be incomplete or unrepresentative. While NLP aids in identifying AAA-related data, human oversight is essential to ensure decisions are informed by the patient's broader clinical context. Ongoing algorithm refinement and seamless integration into clinical workflows are key to improving NLP's utility and reliability in this field.

Inhibition of vascular smooth muscle cell PERK/ATF4 ER stress signaling protects against abdominal aortic aneurysms

Abdominal aortic aneurysms (AAA) are a life-threatening cardiovascular disease for which there is a lack of effective therapy preventing aortic rupture. During AAA formation, pathological vascular remodeling is driven by vascular smooth muscle cell (VSMC) dysfunction and apoptosis, for which the mechanisms regulating loss of VSMCs within the aortic wall remain poorly defined. Using single-cell RNA-Seq of human AAA tissues, we identified increased activation of the endoplasmic reticulum stress response pathway, PERK/eIF2α/ATF4, in aortic VSMCs resulting in upregulation of an apoptotic cellular response. Mechanistically, we reported that aberrant TNF-α activity within the aortic wall induces VSMC ATF4 activation through the PERK endoplasmic reticulum stress response, resulting in progressive apoptosis. In vivo targeted inhibition of the PERK pathway, with VSMC-specific genetic depletion (Eif2ak3fl/fl Myh11-CreERT2) or pharmacological inhibition in the elastase and angiotensin II-induced AAA model preserved VSMC function, decreased elastin fragmentation, attenuated VSMC apoptosis, and markedly reduced AAA expansion. Together, our findings suggest that cell-specific pharmacologic therapy targeting the PERK/eIF2α/ATF4 pathway in VSMCs may be an effective intervention to prevent AAA expansion.

Association between non-alcoholic fatty liver disease and progression of abdominal aortic aneurysm: a multicenter study

BACKGROUND

The purpose of our study was to investigate the association between non-alcoholic fatty liver disease (NAFLD) and abdominal aortic aneurysms (AAA) progression using non-enhanced computed tomography (CT) and CT angiography (CTA).

METHODS

Patients with AAA and age- and sex-matched healthy subjects who underwent abdominal CTA and non-enhanced CT examination between January 2015 and January 2023 from four hospitals were retrospectively analyzed. Patients with AAA were divided into progression (growth rate > 10 mL/year) and non-progression groups, as well as those with NAFLD and without NAFLD, based on abdominal CT results. The Kaplan-Meier and Cox regression were used to investigate the association between NAFLD and AAA progression.

RESULTS

A total of 151 patients with AAA (mean age: 69.1 ± 10.5 years old, 133 men) were included, among which 66 patients (43.7%) had NAFLD. During a median of 10.7 months (6.0-76.0 months), 57 patients (37.7%) had AAA progression. The prevalence of NAFLD was significantly higher in the AAA group compared to the control group (43.7% vs. 31.1%, p = 0.024). Multivariable regression analysis revealed that the NAFLD was independently associated with AAA progression (HR, 4.28; 95% CI, 2.20-8.31; p < 0.001). The area under curve of combined NAFLD and AAA maximal diameter was 0.857 for predicting AAA progression.

CONCLUSIONS

NAFLD on non-enhanced CT is an independent predictor of AAA progression. It can improve the diagnostic efficacy of predicting the progression of abdominal aortic aneurysms.

CLINICAL TRIAL NUMBER

Not applicable. This research is a retrospective analysis.

Tea Polyphenol-Derived Carbon Dots Alleviate Abdominal Aortic Aneurysm Progression by Mitigating Oxidative Stress and Ferroptosis

Abdominal aortic aneurysm (AAA) is a cardiovascular disease with potentially fatal consequences, yet effective therapies to prevent its progression remain unavailable. Oxidative stress is associated with AAA development. Carbon dots have reactive oxygen species-scavenging activity, while green tea extract exhibits robust antioxidant properties. However, the potential of green tea derived carbon dots in mitigating AAA progression has not been fully elucidated. In this study, tea polyphenol carbon dots (TP-CDs) were synthesized via hydrothermal methods and characterized for their antioxidant properties. The antioxidant effects of TP-CDs were evaluated, and TP-CDs' impact on phenotypic transformation, oxidative stress, apoptosis and ferroptosis was investigated comprehensively in an Ang II-induced AAA model, employing techniques such as Western blotting, flow cytometry, and immunohistochemistry. The results revealed that TP-CDs effectively alleviated oxidative stress induced by Ang II stimulation, thereby inhibiting phenotypic transformation, apoptosis, and ferroptosis in vivo. Furthermore, treatment with TP-CDs significantly attenuated AAA progression in a mouse AAA model. Overall, these findings demonstrate that TP-CDs reduced reactive oxygen species levels in the microenvironment and alleviated the progression of AAA, offering a promising therapeutic strategy for this condition.

Inhibition of GPR4 Attenuates the Formation of Abdominal Aortic Aneurysm Through Inhibiting the SP-1/VEGF-A Signaling

Abdominal aortic aneurysm (AAA) is a severe cardiovascular disease (CVD) that is partly attributable to endothelial dysfunction, inflammatory response, and angiogenesis. G protein-coupled receptor 4 (GPR4), a proton-sensitive G protein-coupled receptor that is abundantly expressed in vascular endothelial cells, has been associated with numerous physiological functions. Nevertheless, its potential involvement in the development of AAA remains unexplored. In this study, we examined the impact of GPR4 deletion on the development of AAA in ApoE-deficient mice. The mice were categorized into four distinct groups: the ApoE-/- with saline group, the ApoE-/-GPR4-/- with saline group, the ApoE-/- with Ang II group, and the ApoE-/-GPR4-/- with Ang II group. AAA were induced in the ApoE-/- mice through the perfusion of angiotensin II (Ang II). Notably, GPR4 was substantially elevated in the AAA tissues from both human subjects and experimental mice. The deletion of GPR4 substantially decreased the formation of Ang II-induced AAA, damages to elastin, and the expression of aortic inflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α), as well as vascular endothelial growth factor A/vascular endothelial growth factor receptor 2 (VEGF-A/VEGF-R2), in ApoE-/- mice. Human aortic endothelial cells (HAECs) were transfected with lenti-viral GPR4 shRNA and subsequently stimulated with Ang II. Our findings indicate that the knockout of GPR4 attenuated Ang II-induced angiogenic tube formation in HAECs by decreasing the expression of VEGF-A and VEGF-R2. Furthermore, GPR4 knockout also hindered the activation of specificity protein-1 (SP-1) by reducing its expression and transcriptional activity. Notably, the overexpression of SP-1 reversed the inhibitory effects of GPR4 knockout on angiogenic tube formation and the expression of VEGF-A/VEGF-R2. This suggests that the protective effects of GPR4 knockout are achieved through the inhibition of SP-1. In summary, the absence of GPR4 impeded AAA formation, indicating that GPR4 could potentially serve as a therapeutic target for AAA.

An emerging double‑edged sword role of ferroptosis in cardiovascular disease (Review)

The pathophysiology of cardiovascular disease (CVD) is complex and presents a serious threat to human health. Cardiomyocyte loss serves a pivotal role in both the onset and progression of CVD. Among various forms of programmed cell death, ferroptosis, along with apoptosis, autophagy and pyroptosis, is closely linked to the advancement of CVD. Ferroptosis, a mechanism of cell death, is driven by the buildup of oxidized lipids and excess iron. This pathway is modulated by lipid, amino acid and iron metabolism. Key characteristics of ferroptosis include disrupted iron homeostasis, increased peroxidation of polyunsaturated fatty acids due to reactive oxygen species, decreased glutathione levels and inactivation of glutathione peroxidase 4. Treatments targeting ferroptosis could potentially prevent or alleviate CVD by inhibiting the ferroptosis pathway. Ferroptosis is integral to the pathogenesis of several types of CVD and inhibiting its occurrence in cardiomyocytes could be a promising therapeutic strategy for the future treatment of CVD. The present review provided an in‑depth analysis of advancements in understanding the mechanisms underlying ferroptosis. The present manuscript summarized the interplay between ferroptosis and CVDs, highlighting its dual roles in these conditions. Additionally, potential therapeutic targets within the ferroptosis pathway were discussed, alongside the current limitations and future directions of these novel treatment strategies. The present review may offer novel insights into preventive and therapeutic approaches for CVDs.