Diagnosis and monitoring of abdominal aortic aneurysm: current status and future prospects

Open repair of an abdominal aortic and right common iliac artery aneurysm with idiopathic retroperitoneal fibrosis in a 19-month-old infant

An abdominal aortic aneurysm (AAA) in children is a rare clinical condition, with idiopathic AAAs even more atypical. We report a case of a 19-month-old girl with incidental findings of an infrarenal AAA and right common iliac artery aneurysm during workup for heart failure. Extensive genetic testing was unremarkable for connective tissue disorders. An aortic bi-iliac artery bypass with a Dacron graft from the infrarenal aorta to the right external iliac artery and left common iliac artery was performed. The patient achieved complete recovery and only required one oral hypertensive medication at 30 days of follow-up. Wide patency of the graft was observed on the 3-month follow-up computed tomography angiogram.

Opportunistic Ultrasound Screening for Abdominal Aortic Aneurysm

Objective: In patients with abdominal aortic aneurysm (AAA), early detection and optimal elective treatment before rupture are desirable. In the absence of an established public screening system, opportunistic screening during ultrasound examination for another purpose might be efficacious. The aim of this study was to evaluate the efficacy of opportunistic screening for AAA. Methods: This prospective multicenter observational study enrolled patients who were scheduled to undergo ultrasound for reasons other than AAA. After the ultrasound for the original purpose, evaluation of the abdominal aorta was added. If the abdominal aorta was clear enough for measurement, its diameter and shape were recorded. Furthermore, information on comorbidities was collected for each patient. Results: A total of 10325 patients (echocardiography: 6150; abdominal ultrasound: 4162) from 16 institutions were enrolled. The abdominal aorta was well visualized in 92.9% of patients who underwent echocardiography. Among 9791 patients, AAA was diagnosed in 122 (1.3%) (107 fusiform and 15 saccular), with a diameter range of 30-63 mm. The diagnostic rate increased with age. On multivariate analysis, older age, male sex, coronary artery disease, peripheral arterial disease, and smoking habituation were the risk factors for AAA. Conclusion: Opportunistic screening for AAA was efficacious.

Mortality and burden related with aortic aneurysms and dissections. The importance of information and education

BACKGROUND

In this study we correlated changes of risk factors for cardiovascular diseases with trends of age standardized mortality rates and burden for aortic aneurysms and dissections.

METHODS

We analyzed data from the Global Burden of Diseases and EUROSTAT.

FINDINGS

There was a significant increase of expenditure for health from 1980 and 2019. In the period 1980-2000, despite higher health spending, age standardized mortality rates increased in almost all European countries. During the period 2000-2019, in Western European Countries and in Poland, Estonia, Latvia, Slovenia there was a correlation between higher health expenditure and decrease of ASMR. The most important changes between the period 1980-2000 and the period 2000-2019 was the proportion of health expenditure devoted to preventive care and to the increased use of aspirin and statins.

INTERPRETATION

Information about risk factors for cardiovascular diseases have leads to decreased aortic aneurysm related mortality and burden.

Metabolic clues to aging: exploring the role of circulating metabolites in frailty, sarcopenia and vascular aging related traits and diseases

Background: Physical weakness and cardiovascular risk increase significantly with age, but the underlying biological mechanisms remain largely unknown. This study aims to reveal the causal effect of circulating metabolites on frailty, sarcopenia and vascular aging related traits and diseases through a two-sample Mendelian Randomization (MR) analysis. Methods: Exposures were 486 metabolites analyzed in a genome-wide association study (GWAS), while outcomes included frailty, sarcopenia, arterial stiffness, atherosclerosis, peripheral vascular disease (PAD) and aortic aneurysm. Primary causal estimates were calculated using the inverse-variance weighted (IVW) method. Methods including MR Egger, weighted median, Q-test, and leave-one-out analysis were used for the sensitive analysis. Results: A total of 125 suggestive causative associations between metabolites and outcomes were identified. Seven strong causal links were ultimately identified between six metabolites (kynurenine, pentadecanoate (15:0), 1-arachidonoylglycerophosphocholine, androsterone sulfate, glycine and mannose) and three diseases (sarcopenia, PAD and atherosclerosis). Besides, metabolic pathway analysis identified 13 significant metabolic pathways in 6 age-related diseases. Furthermore, the metabolite-gene interaction networks were constructed. Conclusion: Our research suggested new evidence of the relationship between identified metabolites and 6 age-related diseases, which may hold promise as valuable biomarkers.

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.

Nanoparticles for Thrombus Diagnosis and Therapy: Emerging Trends in Thrombus-theranostics

Cardiovascular disease is one of the chief factors that cause ischemic stroke, myocardial infarction, and venous thromboembolism. The elements that speed up thrombosis include nutritional consumption, physical activity, and oxidative stress. Even though the precise etiology and pathophysiology remain difficult topics that primarily rely on traditional medicine. The diagnosis and management of thrombosis are being developed using discrete non-invasive and non-surgical approaches. One of the emerging promising approach is ultrasound and photoacoustic imaging. The advancement of nanomedicines offers concentrated therapy and diagnosis, imparting efficacy and fewer side effects which is more significant than conventional medicine. This study addresses the potential of nanomedicines as theranostic agents for the treatment of thrombosis. In this article, we describe the factors that lead to thrombosis and its consequences, as well as summarize the findings of studies on thrombus formation in preclinical and clinical models and also provide insights on nanoparticles for thrombus imaging and therapy.

Disturbed hemodynamics and oxidative stress interaction in endothelial dysfunction and AAA progression: Focus on Nrf2 pathway

Hemodynamic shear stress is one of the major factors that are involved in the pathogenesis of many cardiovascular diseases including atherosclerosis and abdominal aortic aneurysm (AAA), through its modulatory effect on the endothelial cell's redox homeostasis and mechanosensitive gene expression. Among important mechanisms, oxidative stress, endoplasmic reticulum stress activation, and the subsequent endothelial dysfunction are attributed to disturbed blood flow and low shear stress in the vascular curvature and bifurcations which are considered atheroprone regions and aneurysm occurrence spots. Many pathways were shown to be involved in AAA progression. Of particular interest from recent findings is, the (Nrf2)/Keap-1 pathway, where Nrf2 is a transcription factor that has antioxidant properties and is strongly associated with several CVDs, yet, the exact mechanism by which Nrf2 alleviates CVDs still to be elucidated. Nrf2 expression is closely affected by shear stress and was shown to participate in AAA. In the current review paper, we discussed the link between disturbed hemodynamics and its effect on Nrf2 as a mechanosensitive gene and its role in the development of endothelial dysfunction which is linked to the progression of AAA.

Using red blood cell distribution width to predict death after abdominal aortic aneurysm rupture

BACKGROUND

An abdominal aortic aneurysm is a life-threatening enlargement in the major vessel at the abdomen level. This study investigated the associations between different levels of red blood cell distribution width and all-cause mortality among patients with abdominal aortic aneurysm rupture. It developed predictive models for all-cause mortality risk.

METHODS

This was a retrospective cohort study using 2001 to 2012 MIMIC-III dataset. The study sample included 392 U.S. adults with abdominal aortic aneurysms who were admitted to ICU after the aneurysm rupture. Then we used two single-factor and four multivariable logistic regression models to examine the associations between different levels of red blood cell distribution and all-cause mortality (30 days and 90 days), controlling for demographics, comorbidities, vital signs, and other laboratory measurements. The receiver operator characteristic curves were calculated, and the areas under the curves were recorded.

RESULTS

There were 140 (35.7%) patients with an abdominal aortic aneurysm in the red blood cell distribution width range between 11.7 and 13.8%, 117 (29.8%) patients in the range between 13.9 and 14.9%, and 135 (34.5%) patients in the range between 15.0 and 21.6%. Patients with higher red blood cell distribution width level (> 13.8%) tended to have a higher mortality rate (both 30 days and 90 days), congestive heart failure, renal failure, coagulation disorders, lower hemoglobin, hematocrit, MCV, red blood cell count, higher levels of chloride, creatinine, sodium, and BUN (All P < 0.05). Results of multivariate logistic regression models indicated that patients with higher red blood cell distribution width levels (> 13.8%) had the highest statistically significant odd ratios of 30 days and 90 days of all-cause mortality than lower red blood cell distribution width levels. The area under the RDW curve was lower (P = 0.0009) than that of SAPSII scores.

CONCLUSIONS

Our study found that patients with abdominal aortic aneurysm rupture with a higher blood cell distribution had the highest risk of all-cause mortality. Using the blood cell distribution width level in patients with abdominal aortic aneurysm rupture to predict mortality should be considered in future clinical practice.

Dexmedetomidine protects cells from Angiotensin II-induced smooth muscle cell phenotype switch and endothelial cell dysfunction

Abdominal aortic aneurysm (AAA) is a vascular disorder greatly threatening life of the elderly population. Dexmedetomidine (DEX), an α2-adrenergic receptor agonist, has been shown to suppress AAA development. Nevertheless, the signaling pathways that might be mediated by DEX in AAA has not been clarified. Vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) were treated with Angiotensin II (Ang II) to mimic AAA in vitro. BrdU, wound healing, and Transwell assays were utilized for measuring VSMC proliferation and migration. Western blotting was used for evaluating protein levels of contractile VSMC markers, collagens and matrix metalloproteinases (MMPs) in VSMCs as well as apoptosis- and HMGB1/TLR4/NF-κB signaling-related markers in ECs. Cell adhesion molecule expression and monocyte-endothelial adhesion were assessed by immunofluorescence staining and adhesion assays. Flow cytometry was implemented for analyzing EC apoptosis. Hematoxylin-eosin staining and ELISA were used to detect the effect of DEX in vivo. In this study, DEX inhibited Ang II-evoked VSMC phenotype switch and extracellular matrix degradation. DEX suppressed the inflammatory response and apoptosis of ECs induced by Ang II. DEX inhibited HMGB1/TLR4/NF-κB signaling pathway in Ang II-treated ECs. DEX attenuated Ang II-induced AAA and inflammation in mice. Overall, DEX ameliorates Ang II-induced VSMC phenotype switch, and inactivates HMGB1/TLR4/NF-κB signaling pathway to alleviate Ang II-induced EC dysfunction.

Molecular and Cellular Mechanisms Involved in Aortic Wall Aneurysm Development

Aortic aneurysms represent a very common pathology that can affect any segment of the aorta. These types of aneurysms can be localized on the thoracic segment or on the abdominal portion, with the latter being more frequent. Though there are similarities between thoracic and abdominal aortic aneurysms, these pathologies are distinct entities. In this article, we undertook a review regarding the different mechanisms that can lead to the development of aortic aneurysm, and we tried to identify the different manners of treatment. For a long time, aortic wall aneurysms may evolve in an asymptomatic manner, but this progressive dilatation of the aneurysm can lead to a potentially fatal complication consisting in aortic rupture. Because there are limited therapies that may delay or prevent the development of acute aortic syndromes, surgical management remains the most common manner of treatment. Even though, surgical management has improved much in the last years, thus becoming less invasive and sophisticated, the morbi-mortality linked to these therapies remains increased. The identification of the cellular and molecular networks triggering the formation of aneurysm would permit the discovery of modern therapeutic targets. Molecular and cellular mechanisms are gaining a bigger importance in the complex pathogenesis of aortic aneurysms. Future studies must be developed to compare the findings seen in human tissue and animal models of aortic aneurysm, so that clinically relevant conclusions about the aortic aneurysm formation and the pharmacological possibility of pathogenic pathways blockage can be drawn.

Abdominal aortic aneurysm screening in an academic family practice: Short-term impact of guideline changes

OBJECTIVE

To investigate abdominal aortic aneurysm (AAA) screening rates in the 6 months before and after the introduction of updated Canadian Task Force on Preventive Health Care (CTFPHC) guidelines to determine effects on practice patterns, as well as to determine whether certain patient characteristics impact AAA screening rates.

DESIGN

Retrospective chart review.

SETTING

Academic family health centre in London, Ont.

PARTICIPANTS

Male patients between the ages of 65 and 80.

MAIN OUTCOME MEASURES

Screening rates for AAA before and after the guideline update were compared using the normal approximation of the binomial distribution. Analysis of demographic characteristic effects on screening rates was completed with the Fisher exact test. Number of visits to the clinic with a primary care provider within the study period and imaging type were collected.

RESULTS

Of the 266 patients included in the study, 160 patients were eligible for screening at the start of the study period, 6 months before publication of the CTFPHC AAA guideline. Individuals eligible for screening visited the clinic an average (SD) of 2.44 (1.82) times in the 6 months before and 2.66 (1.99) times in the 6 months after. Overall, 69 individuals had AAA screening completed and 9 had a discussion of AAA screening without any imaging, for a total uptake rate of 88.5% for those who had screening recommended. The overall imaging rate was 48.9%. There was no statistically significant difference in screening rates between the time periods (P=.337) among those eligible for screening. For demographic characteristics for risk stratification, 7 individuals had a documented family history, of whom 5 had imaging of their abdominal aorta performed, plus 1 additional individual who had screening recommended but not completed. This was not statistically significant relative to the total population (P=.0598). Positive smoking status (active or ex-smoker) was more common, with 135 individuals having a relevant smoking history. Approximately half of these current and former smokers (68 individuals [50.4%]) had any sort of abdominal aortic imaging performed or recommended, which was not statistically significantly different compared with non-smokers (62 of 126 imaging performed or recommended, 49.2%; P=.9016).

CONCLUSION

Screening practices did not change appreciably with the introduction of the CTFPHC AAA screening guidelines. Further research is needed to improve AAA screening rates. It is worth exploring electronic medical record-based reminders, nursing staff involvement in screening, screening programs via public health, and point-of-care ultrasound screening in a primary care setting.

Abdominal Aortic Aneurysms (Etiology, Epidemiology, and Natural History)

Abdominal aortic aneurysm is a potentially lethal condition that is decreasing in frequency as tobacco use declines. The exact etiology remains unknown, but smoking and other perturbations seem to trigger an inflammatory state in the tunica media. Male sex and advanced age are clear demographic risk factors for the development of abdominal aortic aneurysms. The natural history of this disease varies, but screening remains vital as it is rarely diagnosed on physical examination, and elective repair (most commonly done endovascularly) offers significant morbidity and mortality advantages over emergent intervention for aortic rupture.

Identifying novel mechanisms of abdominal aortic aneurysm via unbiased proteomics and systems biology

Background

Abdominal aortic aneurysm (AAA), characterized by a continued expansion of the aorta, leads to rupture if not surgically repaired. Mice aid the study of disease progression and its underlying mechanisms since sequential studies of aneurysm development are not feasible in humans. The present study used unbiased proteomics and systems biology to understand the molecular relationship between the mouse models of AAA and the human disease.

Methods and results

Aortic tissues of developing and established aneurysms produced by either angiotensin II (AngII) infusion in Apoe -/- and Ldlr -/- mice or intraluminal elastase incubation in wildtype C57BL/6J mice were examined. Aortas were dissected free and separated into eight anatomical segments for proteomics in comparison to their appropriate controls. High-dimensional proteome cluster analyses identified site-specific protein signatures in the suprarenal segment for AngII-infused mice (159 for Apoe -/- and 158 for Ldlr -/-) and the infrarenal segment for elastase-incubated mice (173). Network analysis revealed a predominance of inflammatory and coagulation factors in developing aneurysms, and a predominance of fibrosis-related pathways in established aneurysms for both models. To further substantiate our discovery platform, proteomics was performed on human infrarenal aortic aneurysm tissues as well as aortic tissue collected from age-matched controls. Protein processing and inflammatory pathways, particularly neutrophil-associated inflammation, dominated the proteome of the human aneurysm abdominal tissue. Aneurysmal tissue from both mouse and human had inflammation, coagulation, and protein processing signatures, but differed in the prevalence of neutrophil-associated pathways, and erythrocyte and oxidative stress-dominated networks in the human aneurysms.

Conclusions

Identifying changes unique to each mouse model will help to contextualize model-specific findings. Focusing on shared proteins between mouse experimental models or between mouse and human tissues may help to better understand the mechanisms for AAA and establish molecular bases for novel therapies.

Prediction of wall stress and oxygen flow in patient-specific abdominal aortic aneurysms: the role of intraluminal thrombus

In this study, the biomechanical role of intraluminal thrombus (ILT) in an abdominal aortic aneurysm (AAA) is investigated. The implications of ILT in AAA are controversial in literature. Previous studies have demonstrated that ILT provides a biomechanical advantage by decreasing wall stress, whereas other studies have associated ILT with inhibiting oxygen transport and inducing aortic wall weakening. Therefore, we sought to explore the connection between ILT, mechanical stresses, and oxygen flow in different geometries of patient-specific aneurysms with varying ILT morphologies. The objective is to investigate the extent to which ILT influences the prediction of aneurysmal wall stresses that are associated with rupture, as well as oxygen concentrations to measure tissue oxygen deprivation. Three patient-specific AAA geometries are considered, and two models, one with ILT and one without ILT, are created for each patient to assess the effect of ILT presence. A fluid-structure interaction approach is used to couple the blood flow, wall deformation, and oxygen mass transport. Results are presented for hemodynamics patterns, wall stress measures, and oxygen metrics within the arterial wall. While ILT is found to reduce wall stress, simulations confirm that ILT decreases oxygen transport within the tissue significantly, leading to wall hypoxia.

Automatic Detection and Segmentation of Thrombi in Abdominal Aortic Aneurysms Using a Mask Region-Based Convolutional Neural Network with Optimized Loss Functions

The detection and segmentation of thrombi are essential for monitoring the disease progression of abdominal aortic aneurysms (AAAs) and for patient care and management. As they have inherent capabilities to learn complex features, deep convolutional neural networks (CNNs) have been recently introduced to improve thrombus detection and segmentation. However, investigations into the use of CNN methods is in the early stages and most of the existing methods are heavily concerned with the segmentation of thrombi, which only works after they have been detected. In this work, we propose a fully automated method for the whole process of the detection and segmentation of thrombi, which is based on a well-established mask region-based convolutional neural network (Mask R-CNN) framework that we improve with optimized loss functions. The combined use of complete intersection over union (CIoU) and smooth L1 loss was designed for accurate thrombus detection and then thrombus segmentation was improved with a modified focal loss. We evaluated our method against 60 clinically approved patient studies (i.e., computed tomography angiography (CTA) image volume data) by conducting 4-fold cross-validation. The results of comparisons to multiple other state-of-the-art methods suggested the superior performance of our method, which achieved the highest F1 score for thrombus detection (0.9197) and outperformed most metrics for thrombus segmentation.

Cohort Study Examining the Association of Optimal Blood Pressure Control at Entry With Infrarenal Abdominal Aortic Aneurysm Growth

Background and Aim

The benefit of controlling cardiovascular risk factors in slowing the progression of small abdominal aortic aneurysm (AAA) is controversial. This study investigated the association of optimal blood pressure control at entry with the growth of small AAA.

Methods and Results

A total of 1,293 patients with initial AAA diameter <50 mm were followed by a median 5 (inter-quartile range, IQR, 3–7) ultrasound scans for a median of 3.6 years (IQR 1.8, 5.3). Optimal blood pressure control was defined as blood pressure ≤140/90 mmHg at recruitment. The association of optimal blood pressure control at entry with AAA growth was assessed using linear mixed effects models adjusted for established risk factors of AAA growth and factors which were unequally distributed among the blood pressure groups. Optimal blood pressure control at entry was not significantly associated with AAA growth. In the risk factor adjusted model the mean difference in AAA growth between blood pressure groups was 0.04 mm/year (95% CI −0.20, 0.13; p = 0.65). The results were similar in sensitivity analyses excluding outliers or focused on systolic or diastolic blood pressure alone.

Conclusions

This observational study suggests that optimal blood pressure control at entry is not associated with slower AAA growth.

Fully automatic segmentation of abdominal aortic thrombus in pre-operative CTA images using deep convolutional neural networks

BACKGROUND

Endovascular aortic aneurysm repair (EVAR) is currently established as the first-line treatment for anatomically suitable abdominal aortic aneurysm (AAA).

OBJECTIVE

To establish a deep convolutional neural networks (DCNN) model for fully automatic segmentation intraluminal thrombosis (ILT) of abdominal aortic aneurysm (AAA) in pre-operative computed tomography angiography (CTA) images.

METHODS

We retrospectively reviewed 340 patients of AAA with ILT at our single center. The software ITKSNAP was used to draw AAA and ILT region of interests (ROIs), respectively. Image preprocessing and DCNN model build using MATLAB. Randomly divided, 80% of patients was classified as training set, 20% of patients was classified as test set. Accuracy, intersection over union (IOU), Boundary F1 (BF) Score were used to evaluate the predictive effect of the model.

RESULTS

By training in 34760-35652 CTA images (n= 204) and validation in 6968-7860 CTA images (n=68), the DCNN model achieved encouraging predictive performance in test set (n= 68, 6898 slices): Global accuracy 0.9988 ± 5.7735E-05, mean accuracy 0.9546 ± 0.0054, ILT IOU 0.8650 ± 0.0033, aortic lumen IOU 0.8595 ± 0.0085, ILT weighted IOU 0.9976 ± 0.0001, mean IOU 0.9078 ± 0.0029, mean BF Score 0.9829 ± 0.0011. Our DCNN model achieved a mean IOU of more than 90.78% for segmentation of ILT and aortic lumen. It provides a mean relative volume difference between automatic segmentation and ground truth (P> 0.05).

CONCLUSION

An end-to-end DCNN model could be used as an efficient and adjunctive tool for fully automatic segmentation of abdominal aortic thrombus in pre-operative CTA image.

A rare case of thoracic-abdominal aortic aneurysm in conjunction with bilateral superficial femoral artery occlusion, documented with computed tomography angiography

Aneurysms represent bulging of the weakened blood vessel area, as a result of cystic medial degeneration. Aneurysms chance of rupturing increases over time, resulting in bleeding and death. Therefore, patients with aortic aneurysms require frequent monitoring with magnetic resonance and computed tomography angiography, as well as undergoing open repair surgery and endovascular aneurysm repair.

We present a case of ruptured thoracic aortic aneurysm in conjunction with bilateral superficial femoral occlusion, as incidental findings in Covid-19 positive patient.

The patient, a 62-years-old female, presented with cough, shortness of breath, fever and leg claudication. Doppler ultrasonography of the lower limbs was conducted to rule out thromboembolism, revealing bilateral superficial femoral arteries occlusion. The patient was administered high doses of parenteral anticoagulants.

Hemoptysis ensued, prompting an MSCT scan, that showed right pleural effusion, atelectasis, and right active perihilar infiltrates with inter-lobar pleurisy. Due to inflammatory changes on the lung parenchyma, the patient got tested for Sars-Cov-2, and resulted positive.

Contrast-enhanced MSCT also revealed thoracic-abdominal aortic aneurysm with its highest diameter measuring 10 cm, and massive per-aortal thrombus and/or hematoma of 5 cm, which was further ruptured and patient died untreated in the fourth day of hospitalization.

Questions arise whether Covid-19 was the primary cause of bilateral superficial femoral artery occlusion and whether high doses of parenteral anticoagulants were the primary cause of thoracic aortic aneurysm rupture.

Thus, a careful balance must be made between the detrimental and protective contributions of anticoagulants in the patients presenting with Covid-19 and thoracic-abdominal aortic aneurysm.

Urocortins as biomarkers in cardiovascular disease

The urocortins (Ucns) belong to the corticotropin-releasing factor (CRF) family of peptides and have multiple effects within the central nervous and the cardiovascular systems. With growing evidence indicating significant cardioprotective properties and cardiovascular actions of these peptides, the question arises as to whether the plasma profiles of the Ucns are altered in pathologic settings. While reports have shown conflicting results and findings have not been corroborated in multiple independent cohorts, it seems likely that plasma Ucn concentrations are elevated in multiple cardiovascular conditions. The degree of increase and accurate determination of circulating values of the Ucns requires further validation.

Screening for Prevalence of Abdominal Aortic Aneurysm During Transthoracic Echocardiography in Patient With Significant Coronary Artery Disease

Background

Prevalence of abdominal aortic aneurysm (AAA) has ethnic differences, and coronary artery disease (CAD) shares several risk factors with AAA. Sparse Indian data are available on this. We evaluated the prevalence of AAA during transthoracic echocardiography (TTE) and risk factors of AAA in patients with CAD.

Methods

This was a prospective observational study carried out in the cardiology department at a tertiary care center from January 1, 2017 to November 30, 2017. All patients with CAD/acute coronary syndrome (ACS) were included in the study, and patients with AAA due to other etiology were excluded. Screening for an AAA was performed directly using an echocardiographic 3.5-MHz cardiac probe.

Results

A total of 526 patients were screened; and AAA was present in 25 (4.8%) of CAD patients. Smoking, hypertension and hyperlipidemia were predominant risk factors for AAA in our study, but were not statistically significant because same risk factors were also prevalent in the comparison group. Diabetes, peripheral vascular disease and family history were statistically significant risk factors for AAA in our study. The mean size of AAA was 34 mm.

Conclusions

Presence of AAA is significantly higher among CAD patients. CAD shares several risk factors with AAA. Therefore, opportunistic examination of the abdominal aorta during routine TTE could be an effective way of screening. Diabetes mellitus, peripheral artery disease and family history were the significant associated risk factors of AAA in CAD patients.

Based on bioinformatics analysis lncrna SNHG5 modulates the function of vascular smooth muscle cells through mir-205-5p/SMAD4 in abdominal aortic aneurysm

Objective

The aim of this study was to explore expression profiles of long noncoding RNA (lncRNA)‐messenger RNA (mRNA) in abdominal aortic aneurysm (AAA) patients. Further, we explored the mechanisms by which lncRNA SNHG5 modulates the function of vascular smooth muscle cells (VSMC) in AAA.

Methods

Human gene expression profile GSE57691 dataset, was retrieved from Gene Expression Omnibus database. The dataset included gene expression array data of 49 AAA patients and 10 control aortic specimens from organ donors. To explore the main roles of the biological network, differentially expressed lncRNA and mRNAs in the aortic aneurysm (AAA) and normal aortic specimens were determined. Differentially expressed lncRNA and mRNAs were then used to construct a competing endogenous RNA (ceRNA) network using Cytoscape software, and the five key lncRNA were identified. SNHG5 which was significantly downregulated in the AAA was chosen and analysis showed that it regulates mir‐205‐5p and SMAD4 by binding to mir‐205‐5p. Double luciferase reporter gene assays, RNA immunoprecipitation, and RNA knockdown studies were used to establish the relationship between SNHG5 and mir‐205‐5p. Apoptosis rate was determined using flow cytometry, whereas cell proliferation was evaluated using Edu, and 24 well Transwell assay. Western blot analysis was used to determine protein expression levels.

Results

The five differentially expressed lncRNAs were significantly correlated with 34 microRNAs and 112 mRNAs. mRNAs in the ceRNA network are implicated in protein binding, signal transduction, DNA and RNA transcription, development, and cell differentiation. SNHG5 was downregulated in the AAA and acts as a molecular sponge for mir‐205. Downregulation of SNHG5 induces expression of mir‐205‐5p. Increased mir‐205‐5p expression level inhibits SMAD4 production, thus inhibiting proliferation and migration and promotes apoptosis of smooth muscle cells.

Conclusion

Bioinformatics were used to explore molecular mechanism of AAA progression. The findings of this study show that lncRNA SNHG5 regulates proliferation and apoptosis of VSMC cells through modulation of the mir‐205‐5p/SMAD4 axis. Therefore, SNHG5 is a potential therapeutic target for AAA disease.

Review of Malpractice Lawsuits in the Diagnosis and Management of Aortic Aneurysms and Aortic Dissections

OBJECTIVE

Aortic aneurysms and dissections are prevalent causes of morbidity and mortality. The management of aortic pathologies may be called into question in malpractice suits. Malpractice claims were analyzed to understand common reasons for litigation, medical specialties involved, patient injuries, and outcomes.

METHODS

Litigation cases in the Westlaw database from September 1st, 1987 to October 23 rd, 2019 were analyzed. Search terms included "aortic aneurysm" and "aortic dissection." Data on plaintiff, defendant, litigation claims, patient injuries, misdiagnoses, and case outcomes were collected and compared for aortic aneurysms, aortic dissections, and overall cases.

RESULTS

A total of 346 cases were identified, 196 involving aortic aneurysms and 150 aortic dissections. Physician defendants were emergency medicine (29%), cardiology (20%), internal medicine (14%), radiology (11%), cardiothoracic (10%) and vascular surgery (10%). Litigation claims included "failure to diagnose and treat" (61%), "delayed diagnosis and treatment" (21%), "post-operative complications after open repair" (10%) and "negligent post-operative care" (10%). Patients with aneurysms presented with abdominal (63%) and back pain (37%), while dissections presented with chest pain (78%), abdominal pain (15%), and shortness of breath (14%). Misdiagnoses included gastrointestinal (12%), other cardiovascular (9%), and musculoskeletal conditions (9%), but many were not specified (58%). Overall, 83% of cases were wrongful death suits. Injuries included loss of consortium (23%), emotional distress (19%), and bleeding (17%). In 53% of the cases, the jury ruled in favor of the defendant. 25% of cases ruled for the plaintiff. 22% of cases resulted in a settlement. The mean rewarded for each case was $1,644,590.66 (SD: $5,939,134.58; Range: $17,500-$68,035,462).

CONCLUSION

For aortic pathologies, post-operative complications were not prominent among the reasons why suits were brought forth. This suggests improvements in education across all involved medical specialties may allow for improved diagnostic accuracy and efficient treatment, which could then translate to a decrease in associated litigation cases.

Development of a novel index to characterise arterial dynamics using ultrasound imaging

Abdominal aortic aneurysms (AAA) are associated with systemic inflammation and endothelial dysfunction. We previously reported flow mediated dilatation (FMD) of the brachial artery as a predictor of AAA growth. We hence hypothesised that other physical characteristics of the brachial artery correlate with AAA growth. Using a prospectively cohort of AAA patients, we devised a 'brachial artery relaxation index' (BARI) and examined its role as a biomarker for AAA growth. However, no correlation between BARI and future aneurysm growth was observed (p = 0.45). Therefore, our investigations did not substantiate the hypothesis that other physical characteristics of the brachial artery predicts AAA growth.

Gender-Based Differences in Abdominal Aortic Aneurysm Rupture: A Retrospective Study

Background

Annually, 5% of sudden deaths are due to abdominal aortic aneurysm (AAA) rupture. There is evidence suggesting that AAA ruptures have worse outcomes in females than males and the aneurysms rupture at a smaller size in females than in males. The United States Preventive Services Task Force (USPSTF) recommends a one-time ultrasound screening for males aged 65 - 75 years who ever smoked. There is insufficient evidence to screen females aged 65 - 75 years who ever smoked though there is evidence suggesting that AAAs rupture at a smaller size and have worse outcomes in females. The objective of this study is to compare the characteristics, mortality and morbidity of ruptured AAAs in females and males.

Methods

This is a retrospective review of 117 patients from two teaching institutions over a period of 6 years. A total of 39 parameters were compared between males and females including demographic variables, comorbidities like hypertension, dyslipidemia, cardiovascular diseases; previous history of AAA; medications, characteristics of aneurysm, type of surgery and its outcome; postoperative complications and long-term survival.

Results

The overall incidence of AAA rupture was higher in males (68%) than in females (32%). Females die from AAA rupture at a later age. There was a significant difference in the size of AAA rupture between females (mean = 7.4 cm, standard deviation (SD) = 2.0) and males (mean = 8.2 cm, SD = 1.8; P = 0.04). The probability to undergo surgery for ruptured AAA was significantly lower for females as compared to males (P = 0.03). Females had higher overall mortality (P = 0.001), postoperative mortality (P = 0.02), higher length of intensive care unit (ICU) stay, incidence of postoperative complications, use of vasopressors and use of ventilator.

Conclusions

Using a similar threshold of size of AAA for elective surgery for both males and females might not be appropriate. Further population-based studies are needed to warrant AAA screening for high-risk females owing to the higher morbidity and mortality.

Combining Bioinformatics Techniques to Study the Key Immune-Related Genes in Abdominal Aortic Aneurysm

Approximately 13,000 people die of an abdominal aortic aneurysm (AAA) every year. This study aimed to identify the immune response-related genes that play important roles in AAA using bioinformatics approaches. We downloaded the GSE57691 and GSE98278 datasets related to AAA from the Gene Expression Omnibus database, which included 80 AAA and 10 normal vascular samples. CIBERSORT was used to analyze the samples and detect the infiltration of 22 types of immune cells and their differences and correlations. The principal component analysis showed significant differences in the infiltration of immune cells between normal vascular and AAA samples. High proportions of CD4⁺ T cells, activated mast cells, resting natural killer cells, and 12 other types of immune cells were found in normal vascular tissues, whereas high proportions of macrophages, CD8⁺ T cells, resting mast cells, and six other types of immune cells were found in AAA tissues. In the selected samples, we identified 39 upregulated (involved in growth factor activity, hormone receptor binding, and cytokine receptor activity) and 133 downregulated genes (involved in T cell activation, cell chemotaxis, and regulation of immune response mediators). The key differentially expressed immune response-related genes were screened using the STRING database and Cytoscape software. Two downregulated genes, PI3 and MAP2K1, and three upregulated genes, SSTR1, GPER1, and CCR10, were identified by constructing a protein-protein interaction network. Functional enrichment of the differentially expressed genes was analyzed, and the expression of the five key genes in AAA samples was verified using quantitative polymerase chain reaction, which revealed that MAP2K1 was downregulated in AAA, whereas SSTR1, GEPR1, and CCR10 were upregulated; there was no significant difference in PI3 expression. Our study shows that normal vascular and AAA samples can be distinguished via the infiltration of immune cells. Five genes, PI3, MAP2K1, SSTR1, GPER1, and CCR10, may play important roles in the development, diagnosis, and treatment of AAA.

Brahma-Related Gene 1 Deficiency in Endothelial Cells Ameliorates Vascular Inflammatory Responses in Mice

Endothelial dysfunction plays an important role in promoting the progression of disease genesis such as atherosclerosis and abdominal aortic aneurysm (AAA). The physiological unbalance of endothelial cells is a major pathological basis. In this present study, we investigated Brahma-related gene 1 (BRG1), a chromatin remodeling protein, was in mouse models of diabetic atherosclerosis and AAA, focusing on its role in endothelial dysfunction. We report that compared with their wild-type (WT, ApoE^–/–; BRG1^fl/fl) littermates, endothelium conditional BRG1 knockout mice (CKO, ApoE^–/–; BRG1^fl/fl; CDH5-cre) exhibited an alleviated phenotype of diabetic atherosclerosis. Immunohistochemically staining and real-time PCR analysis demonstrated fewer macrophages recruitment with a reduction of vascular inflammatory in CKO mice compared with WT mice. Further research in the Ang-II induced AAA model revealed that BRG1 deficiency had the protective effects on endothelium conditional BRG1 deletion, evidenced by the downregulation of pro-inflammatory mediators [interleukin (IL)-1β and IL-6, not tumor necrosis factor-α (TNF-α)] in the vessels of CKO mice compared with WT mice. In Ea.hy926 cell lines, anti-BRG1 small interfering RNA and PFI-3 treatment obviously alleviated tumor necrosis factor-α-induced IL-6 and CCL2 expression, and further research demonstrated that the BRG1 inhibition in endothelial cells not only decreased c-Fos expression but also blocked the c-Fos translocation into nuclei. In conclusion, our results suggest that endothelial BRG1 deficiency may protect the mice from diabetic atherosclerosis and AAA via inhibiting inflammatory response in vessels.

Tropoelastin: an in vivo imaging marker of dysfunctional matrix turnover during abdominal aortic dilation

Aims

Dysfunctional matrix turnover is present at sites of abdominal aortic aneurysm (AAA) and leads to the accumulation of monomeric tropoelastin rather than cross-linked elastin. We used a gadolinium-based tropoelastin-specific magnetic resonance contrast agent (Gd-TESMA) to test whether quantifying regional tropoelastin turnover correlates with aortic expansion in a murine model. The binding of Gd-TESMA to excised human AAA was also assessed.

Methods and results

We utilized the angiotensin II (Ang II)-infused apolipoprotein E gene knockout (ApoE^-/-) murine model of aortic dilation and performed in vivo imaging of tropoelastin by administering Gd-TESMA followed by late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) and T₁ mapping at 3 T, with subsequent ex vivo validation. In a cross-sectional study (n = 66; control = 11, infused = 55) we found that Gd-TESMA enhanced MRI was elevated and confined to dilated aortic segments (control: _LGE=0.13 ± 0.04 mm², control _R1= 1.1 ± 0.05 s^-1 vs. dilated _LGE=1.0 ± 0.4 mm², dilated _R1 =2.4 ± 0.9 s^-1) and was greater in segments with medium (8.0 ± 3.8 mm³) and large (10.4 ± 4.1 mm³) compared to small (3.6 ± 2.1 mm³) vessel volume. Furthermore, a proof-of-principle longitudinal study (n = 19) using Gd-TESMA enhanced MRI demonstrated a greater proportion of tropoelastin: elastin expression in dilating compared to non-dilating aortas, which correlated with the rate of aortic expansion. Treatment with pravastatin and aspirin (n = 10) did not reduce tropoelastin turnover (0.87 ± 0.3 mm² vs. 1.0 ± 0.44 mm²) or aortic dilation (4.86 ± 2.44 mm³ vs. 4.0 ± 3.6 mm³). Importantly, Gd-TESMA-enhanced MRI identified accumulation of tropoelastin in excised human aneurysmal tissue (n = 4), which was confirmed histologically.

Conclusion

Tropoelastin MRI identifies dysfunctional matrix remodelling that is specifically expressed in regions of aortic aneurysm or dissection and correlates with the development and rate of aortic expansion. Thus, it may provide an additive imaging marker to the serial assessment of luminal diameter for surveillance of patients at risk of or with established aortopathy.

Deficiency of peroxiredoxin 2 exacerbates angiotensin II-induced abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is an inflammatory vascular disease characterized by structural deterioration of the aorta caused by inflammation and oxidative stress, leading to aortic dilatation and rupture. Peroxiredoxin 2 (PRDX2), an antioxidant enzyme, has been reported as a potential negative regulator of inflammatory vascular diseases, and it has been identified as a protein that is increased in patients with ruptured AAA compared to patients with nonruptured AAA. In this study, we demonstrated that PRDX2 was a pivotal factor involved in the inhibition of AAA progression. PRDX2 levels were increased in AAA compared with those in normal aortas in both humans and mice. Ultrasound imaging revealed that the loss of PRDX2 accelerated the development of AAA in the early stages and increased AAA incidence in mice infused with angiotensin II (Ang II). Prdx2^−/− mice infused with Ang II exhibited increased aortic dilatation and maximal aortic diameter without a change in blood pressure. Structural deterioration of the aortas from Prdx2^−/− mice infused with Ang II was associated with increases in the degradation of elastin, oxidative stress, and intramural thrombi caused by microhemorrhages, immature neovessels, and the activation of matrix metalloproteinases compared to that observed in controls. Moreover, an increase in inflammatory responses, including the production of cell adhesion molecules and the accumulation of inflammatory cells and proinflammatory cytokines due to PRDX2 deficiency, accelerated Ang II-induced AAA progression. Our data confirm that PRDX2 plays a role as a negative regulator of the pathological process of AAA and suggest that increasing PRDX2 activity may be a novel strategy for the prevention and treatment of AAA.

An enzyme with antioxidant properties may provide a biomarker and therapeutic agent to help treat abdominal aortic aneurysm (AAA). AAA involves the structural deterioration of the aorta through chronic inflammation and oxidative stress, and can trigger life-threatening artery rupture. An antioxidant enzyme called peroxiredoxin 2 (PRDX2) is increased in patients with ruptures, but whether its role in AAA is beneficial or detrimental is unclear. Goo Taeg Oh at the Ewha Womans University in Seoul, Jong-Gil Park at the Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea, and co-workers examined the effect of PRDX2 on AAA progression. PRDX2 suppressed structural damage in mice, limiting artery dilation and protein degradation. Loss of PRDX2 accelerated AAA development. Measuring levels of PRDX2 may indicate AAA severity in patients, while boosting the enzyme could repair aortic damage.

Evolving Utility of Endovascular Treatment of Juxtarenal, Pararenal, and Suprarenal Abdominal Aortic Aneurysms Associated With Increased Risk of Mortality Over Time

BACKGROUND

Continued advances in endovascular technologies are resulting in fewer open abdominal aortic aneurysm (AAA) repairs. In addition, more complex juxtarenal, pararenal, and suprarenal (JPS) AAAs are being managed with various endovascular techniques. This study sought to evaluate the evolving trends in endovascular aneurysm repair (EVAR) of AAAs, hypothesizing increased rate of JPS AAA repair by EVAR. We also sought to evaluate the risk for morbidity and mortality for EVAR and open aneurysm repair (OAR) of JPS AAAs over time.

METHODS

The 2011-2017 American College of Surgeons National Surgical Quality Improvement Program Procedure-Targeted Vascular database was queried for patients undergoing OAR or EVAR for AAAs. A multivariable logistic regression analysis was performed for both infrarenal and JPS AAA repairs.

RESULTS

Of 18,661 patients who underwent AAA repair, 3,941 (21.1%) were OAR and 14,720 (78.9%) were EVAR. The rate of OAR decreased from 29.5% in 2011 to 21.3% in 2017 (P < 0.001) with a geometric-mean-annual decrease of 27.8%. The rate of EVAR increased from 70.5% to 78.7% during the same time period (P < 0.001) with a geometric-mean-annual increase of 11.6%. These trends remained true for both infrarenal and JPS AAAs. After adjusting for covariates, there was no difference in associated risk of 30-day mortality, renal complications, or ischemic colitis for either OAR or EVAR over each incremental year for infrarenal AAAs (P > 0.05). However, in patients undergoing EVAR for JPS AAAs, the associated risk of mortality increased with each incremental year (odds ratio [OR]: 1.30, confidence interval [CI]: 1.01-1.69, P = 0.039), whereas there was no difference in the risk of mortality for OAR of JPS AAAs with each incremental year (OR: 1.11, CI: 0.99-1.23, P = 0.067).

CONCLUSIONS

The rate of OAR for AAA has decreased over the past seven years with an increase in EVAR, particularly for more complex JPS AAAs. The associated risk for morbidity and mortality for treatment of infrarenal AAAs was not significantly affected by this increased utility of EVAR. The associated risk of mortality for JPS AAAs treated by EVAR increased over time, whereas this trend for associated risk of mortality was not seen for OAR of JPS AAAs. These findings, especially the increased associated risk of mortality over time with EVAR for JPS AAAs, warrant careful prospective analysis.

MicroRNA-29a-3p regulates abdominal aortic aneurysm development and progression via direct interaction with PTEN

Various research studies have been conducted in deducing the role of microRNAs (miRNAs) in the pathogenesis and physiological processes of various systematic diseases. This study aims at demonstration of the important role played by miR-29a-3p, through association with phosphatase and tensin homolog (PTEN), in the regulation of abdominal aortic aneurysm development and progression. Quantitative real-time polymerase chain reaction (RT-qPCR) examined miRNA-19a-3p and PMEPA1 expression in multiplied vascular smooth muscle cells (VSMCs). Cell transfection upregulated or downregulated the genes and cell counting kit-8 assay determined cellular viability. RT-qPCR detected cellular proliferation and cell death using the cell proliferation and apoptosis biomarkers Ki87 and proliferating cell nuclear antigen, caspase-8 and caspase-3, respectively. Furthermore, luciferase assay analyzed the luciferase activity and western blot analysis determined miRNA-19a-3p and PMEPA1 protein expression in proliferation and apoptosis biomarkers. TargetScan 4.2 online software (www.targetscan.org) was used to perform the bioinformatics analysis so as to forecast the putative targets of miR-29a-3p and PTEN. The results inferred that there was an increased expression of miRNA-29a-3p found in AAA-mimic cells with increased cellular viability and significant pathological apoptosis. Further, when the expression of miRNA-29a-3p was downregulated, it reduced the cell viability of AAA cells. On the basis of the gene interplays, it can be understood that the PTEN was directly targeted by miRNA-29a-3p so as to regulate the AAA progression. Thus, PTEN was found to strengthen the proliferation effect of miRNA-29a-3p in AAA cells. The current study thus shed more insights about the molecular mechanistic roles of miRNA-29a-3p and PTEN, opening doors for novel therapeutic approach to AAA.

Abdominal aortic calcification: from ancient friend to modern foe

Background

Abdominal aortic calcifications were already ubiquitous in ancient populations from all continents. Although nowadays generally considered as an innocent end stage of stabilised atherosclerotic plaques, increasing evidence suggests that arterial calcifications contribute to cardiovascular risk. In this review we address abdominal aortic calcification from an evolutionary perspective and review the literature on histology, prevalence, risk factors, clinical outcomes and pharmacological interventions of abdominal aortic calcification.

Design

The design of this study was based on a literature review.

Methods

Pubmed and Embase were systematically searched for articles on abdominal aortic calcification and its synonyms without language restrictions. Articles with data on histology, prevalence, risk factors clinical outcomes and/or pharmacological interventions were selected.

Results

Abdominal aortic calcification is highly prevalent in the general population and prevalence and extent increase with age. Prevalence and risk factors differ between males and females and different ethnicities. Risk factors include traditional cardiovascular risk factors and decreased bone mineral density. Abdominal aortic calcification is shown to contribute to arterial stiffness and is a strong predictor of cardiovascular events and mortality. Several therapies to inhibit arterial calcification have been developed and investigated in small clinical trials.

Conclusions

Abdominal aortic calcification is from all eras and increasingly acknowledged as an independent contributor to cardiovascular disease. Large studies with long follow-up must be carried out to show whether inhibition of abdominal aortic calcification will further reduce cardiovascular risk.

Targeted Gold Nanoparticles as an Indicator of Mechanical Damage in an Elastase Model of Aortic Aneurysm

Elastin is a key structural protein and its pathological degradation deterministic in aortic aneurysm (AA) outcomes. Unfortunately, using current diagnostic and clinical surveillance techniques the integrity of the elastic fiber network can only be assessed invasively. To address this, we employed fragmented elastin-targeting gold nanoparticles (EL-AuNPs) as a diagnostic tool for the evaluation of unruptured AAs. Electron dense EL-AuNPs were visualized within AAs using micro-computed tomography (micro-CT) and the corresponding Gold-to-Tissue volume ratios quantified. The Gold-to-Tissue volume ratios correlated strongly with the concentration (0, 0.5, or 10 U/mL) of infused porcine pancreatic elastase and therefore the degree of elastin damage. Hyperspectral mapping confirmed the spatial targeting of the EL-AuNPs to the sites of damaged elastin. Nonparametric Spearman's rank correlation indicated that the micro-CT-based Gold-to-Tissue volume ratios had a strong correlation with loaded (ρ = 0.867, p-val = 0.015) and unloaded (ρ = 0.830, p-val = 0.005) vessel diameter, percent dilation (ρ = 0.976, p-val = 0.015), circumferential stress (ρ = 0.673, p-val = 0.007), loaded (ρ = - 0.673, p-val = 0.017) and unloaded (ρ = - 0.697, p-val = 0.031) wall thicknesses, circumferential stretch (ρ = - 0.7234, p-val = 0.018), and lumen area compliance (ρ = - 0.831, p-val = 0.003). Likewise, in terms of axial force and axial stress vs. stretch, the post-elastase vessels were stiffer. Collectively, these findings suggest that, when combined with CT imaging, EL-AuNPs can be used as a powerful tool in the non-destructive estimation of mechanical and geometric features of AAs.

Deficiency of immunoglobulin E protects mice from experimental abdominal aortic aneurysms

Allergic asthma with high plasma IgE levels is a significant risk factor of human abdominal aortic aneurysm (AAA). This study tests a direct role of IgE in angiotensin-II (Ang-II) perfusion- and peri-aortic CaCl2 injury-induced AAA in mice. In both models, IgE-deficiency in Apoe-/- Ige-/- mice blunts AAA growth and reduces lesion accumulation of macrophages, CD4+ and CD8+ T cells, and lesion MHC class-II expression, CD31+ microvessel growth, and media smooth muscle cell loss, compared with those from Apoe-/- control mice. Real time-PCR reveals significant reductions in expression of neutrophil chemoattractants MIP-2α and CXCL5 in AAA lesions or macrophages from Apoe-/- Ige-/- mice, along with reduced lesion Ly6G+ neutrophil accumulation. Consistent with reduced lesion inflammatory cell accumulation, we find significant reductions of plasma and AAA lesion IL6 expression in Apoe-/- Ige-/- mice. Immunofluorescent staining and FACS analysis show that AAA lesion neutrophils express FcεR1. Mechanistic study demonstrates that IgE induces neutrophil FcεR1 expression, activates MAPK signaling, and promotes IL6 production. This study supports a direct role of IgE in AAA by promoting lesion chemokine expression, inflammatory cell accumulation, MAPK signaling, and cytokine expression. IgE inhibition may represent a novel therapeutic approach in AAA management.

Deficiency of IL12p40 (Interleukin 12 p40) Promotes Ang II (Angiotensin II)-Induced Abdominal Aortic Aneurysm

Objective- Abdominal aortic aneurysm is caused by the accumulation of inflammatory cells in the aortic wall. Our recent studies demonstrated that inhibition of Notch signaling attenuates abdominal aortic aneurysm formation by shifting the macrophage balance towards anti-inflammatory (M2) phenotype. Using IL12p40^-/- (interleukin 12 p40) mice, we investigated the effects of M2-predominant macrophages on the development of abdominal aortic aneurysm. Approach and Results- Male (8-10 week-old) wild-type and IL12p40^-/- mice (n=15) on C57BL/6 background were infused with Ang II (angiotensin II, 1000 ng/kg per minute) by implanting osmotic pumps subcutaneously for 28 days. In the IL12p40^-/- mice, Ang II significantly increased the maximal intraluminal diameter (9/15) as determined by transabdominal ultrasound imaging. In addition, IL12p40-deletion significantly increased aortic stiffness in response to Ang II as measured by pulse wave velocity and atomic force microscopy. Histologically, IL12p40^-/- mice exhibited increased maximal external diameter of aorta and aortic lesions associated with collagen deposition and increased elastin fragmentation compared with wild-type mice infused with Ang II. Mechanistically, IL12p40 deficiency by siRNA (small interfering RNA) augmented the Tgfβ2-mediated Mmp2 expression in wild-type bone marrow-derived macrophages without affecting the expression of Mmp9. No such effects of IL12p40 deficiency on MMP2/MMP9 was observed in human aortic smooth muscle cells or fibroblasts. Depletion of macrophages in IL12p40^-/- mice by clodronate liposomes significantly decreased the maximal external diameter of aorta and aortic stiffness in response to Ang II as determined by imaging and atomic force microscopy. Conclusions- IL12p40 depletion promotes the development of abdominal aortic aneurysm, in part, by facilitating recruitment of M2-like macrophages and potentiating aortic stiffness and fibrosis mediated by Tgfβ2.

Randomized Placebo-Controlled Trial Assessing the Effect of 24-Week Fenofibrate Therapy on Circulating Markers of Abdominal Aortic Aneurysm: Outcomes From the FAME -2 Trial

Background

There is no drug therapy for abdominal aortic aneurysm (AAA). FAME‐2 (Fenofibrate in the Management of Abdominal Aortic Aneurysm 2) was a placebo‐controlled randomized trial designed to assess whether administration of 145 mg of fenofibrate/d for 24 weeks favorably modified circulating markers of AAA.

Methods and Results

Patients with AAAs measuring 35 to 49 mm and no contraindication were randomized to fenofibrate or identical placebo. The primary outcome measures were the differences in serum osteopontin and kallistatin concentrations between groups. Secondary analyses compared changes in the circulating concentration of AAA‐associated proteins, and AAA growth, between groups using multivariable linear mixed‐effects modeling. A total of 140 patients were randomized to receive fenofibrate (n=70) or placebo (n=70). By the end of the study 3 (2.1%) patients were lost to follow‐up and 18 (12.9%) patients had ceased trial medication. A total of 85% of randomized patients took ≥80% of allocated tablets and were deemed to have complied with the medication regimen. Patients’ allocated fenofibrate had expected reductions in serum triglycerides and estimated glomerular filtration rate, and increases in serum homocysteine. No differences in serum osteopontin, kallistatin, or AAA growth were observed between groups.

Conclusions

Administering 145 mg/d of fenofibrate for 24 weeks did not significantly reduce serum concentrations of osteopontin and kallistatin concentrations, or rates of AAA growth in this trial. The findings do not support the likely benefit of fenofibrate as a treatment for patients with small AAAs.

Clinical Trial Registration

URL: http://www.anzctr.org.au. Unique identifier: ACTRN12613001039774.

Vitamin D as A Protector of Arterial Health: Potential Role in Peripheral Arterial Disease Formation

Atherosclerotic occlusive diseases and aneurysms that affect large and medium-sized arteries outside the cardiac and cerebral circulation are collectively known as peripheral arterial disease (PAD). With a rise in the rate of aging population worldwide, the number of people diagnosed with PAD is rapidly increasing. The micronutrient vitamin D is an important steroid hormone that acts on many crucial cellular mechanisms. Experimental studies suggest that optimal levels of vitamin D have beneficial effects on the heart and blood vessels; however, high vitamin D concentrations have been implicated in promoting vascular calcification and arterial stiffness. Observations from various clinical studies shows that deficiency of vitamin D has been associated with a greater risk of PAD. Epidemiological studies have often reported an inverse relation between circulating vitamin D status measured in terms of 25-hydroxivitamin D [25(OH)D] levels and increased cardiovascular disease risk; however, randomized controlled trials did not show a consistent positive effect of vitamin D supplementation on cardiovascular disease risk or events. Even though PAD shares all the major risk factors with cardiovascular diseases, the effect of vitamin D deficiency in PAD is not clear. Current evidence suggests a strong role of vitamin D in promoting genomic and epigenomic changes. This review summarises the current literature that supports the notion that vitamin D deficiency may promote PAD formation. A better understanding of underlying pathological mechanisms will open up new therapeutic possibilities which is the main unmet need in PAD management. Furthermore, epigenetic evidence shows that a more holistic approach towards PAD prevention that incorporates a healthy lifestyle, adequate exercise and optimal nutrition may be more effective in protecting the genome and maintaining a healthy vasculature.

Nanotherapies for Treatment of Cardiovascular Disease: A Case for Antioxidant Targeted Delivery

Purpose of Review

Cardiovascular disease (CVD) involves a broad range of clinical manifestations resulting from a dysfunctional vascular system. Overproduction of reactive oxygen and nitrogen species are causally implicated in the severity of vascular dysfunction and CVD. Antioxidant therapy is an attractive avenue for treatment of CVD associated pathologies. Implementation of targeted nano-antioxidant therapies has the potential to overcome hurdles associated with systemic delivery of antioxidants. This review examines the currently available options for nanotherapeutic targeting CVD, and explores successful studies showcasing targeted nano-antioxidant therapy.

Recent Findings

Active targeting strategies in the context of CVD heavily focus on immunotargeting to inflammatory markers like cell adhesion molecules, or to exposed extracellular matrix components. Targeted antioxidant nanotherapies have found success in pre-clinical studies.

Summary

This review underscores the potential of targeted nanocarriers as means of finding success translating antioxidant therapies to the clinic, all with a focus on CVD.

Effect of Cyclic Stretch on Vascular Endothelial Cells and Abdominal Aortic Aneurysm (AAA): Role in the Inflammatory Response

Abdominal aortic aneurysm (AAA) is a focal dilatation of the aorta, caused by both genetic and environmental factors. Although vascular endothelium plays a key role in AAA progression, the biological mechanisms underlying the mechanical stress involvement are only partially understood. In this study, we developed an in vitro model to characterize the role of mechanical stress as a potential trigger of endothelial deregulation in terms of inflammatory response bridging between endothelial cells (ECs), inflammatory cells, and matrix remodeling. In AAA patients, data revealed different degrees of calcification, inversely correlated with wall stretching and also with inflammation and extracellular matrix degradation. In order to study the role of mechanical stimulation, endothelial cell line (EA.hy926) has been cultured in healthy (10% strain) and pathological (5% strain) dynamic conditions using a bioreactor. In presence of tumor necrosis factor alpha (TNF-α), high levels of matrix metalloproteinase-9 (MMP-9) expression and inflammation are obtained, while mechanical stimulation significantly counteracts the TNF-α effects. Moreover, physiological deformation also plays a significant role in the control of the oxidative stress. Overall our findings indicate that, due to wall calcification, in AAA there is a significant change in terms of decreased wall stretching.

Macrophage-derived netrin-1 promotes abdominal aortic aneurysm formation by activating MMP3 in vascular smooth muscle cells

Abdominal aortic aneurysms (AAA) are characterized by extensive extracellular matrix (ECM) fragmentation and inflammation. However, the mechanisms by which these events are coupled thereby fueling focal vascular damage are undefined. Here we report through single-cell RNA-sequencing of diseased aorta that the neuronal guidance cue netrin-1 can act at the interface of macrophage-driven injury and ECM degradation. Netrin-1 expression peaks in human and murine aneurysmal macrophages. Targeted deletion of netrin-1 in macrophages protects mice from developing AAA. Through its receptor neogenin-1, netrin-1 induces a robust intracellular calcium flux necessary for the transcriptional regulation and persistent catalytic activation of matrix metalloproteinase-3 (MMP3) by vascular smooth muscle cells. Deficiency in MMP3 reduces ECM damage and the susceptibility of mice to develop AAA. Here, we establish netrin-1 as a major signal that mediates the dynamic crosstalk between inflammation and chronic erosion of the ECM in AAA.

Abdominal aortic aneurysms (AAA) are characterized by extensive extracellular matrix degradation. Here Hadi et al. identify a netrin-1/neogenin-based crosstalk between macrophages and vascular smooth muscle cells (VSMCs), leading to the secretion of the matrix metalloproteinase MMP-3 by VSMCs and subsequent matrix degradation in AAA lesions.

VPO1 Modulates Vascular Smooth Muscle Cell Phenotypic Switch by Activating Extracellular Signal-regulated Kinase 1/2 (ERK 1/2) in Abdominal Aortic Aneurysms

Background Hydrogen peroxide (H2O2) is a critical molecular signal in the development of abdominal aortic aneurysm ( AAA ) formation. Vascular peroxidase 1 ( VPO 1) catalyzes the production of hypochlorous acid ( HOC l) from H2O2 and significantly enhances oxidative stress. The switch from a contractile phenotype to a synthetic one in vascular smooth muscle cells ( VSMC s) is driven by reactive oxygen species and is recognized as an early and important event in AAA formation. This study aims to determine if VPO 1 plays a critical role in the development of AAA by regulating VSMC phenotypic switch. Methods and Results VPO 1 is upregulated in human and elastase-induced mouse aneurysmal tissues compared with healthy control tissues. Additionally, KLF 4, a nuclear transcriptional factor, is upregulated in aneurysmatic tissues along with a concomitant downregulation of differentiated smooth muscle cell markers and an increase of synthetic phenotypic markers, indicating VSMC phenotypic switch in these diseased tissues. In cultured VSMC s from rat abdominal aorta, H2O2 treatment significantly increases VPO 1 expression and HOC l levels as well as VSMC phenotypic switch. In support of these findings, depletion of VPO 1 significantly attenuates the effects of H2O2 and HOC l treatment. Furthermore, HOC l treatment promotes VSMC phenotypic switch and ERK 1/2 phosphorylation. Pretreatment with U0126 (a specific inhibitor of ERK 1/2) significantly attenuates HOC l-induced VSMC phenotypic switch. Conclusions Our results demonstrate that VPO 1 modulates VSMC phenotypic switch through the H2O2/ VPO 1/ HOC l/ ERK 1/2 signaling pathway and plays a key role in the development of AAA . Our findings also implicate VPO 1 as a novel signaling node that mediates VSMC phenotypic switch and plays a key role in the development of AAA . Clinical Trial Registration URL : www.chictr.org.cn . Unique identifier: Chi CTR 1800016922.

MicroRNA‑26a protects vascular smooth muscle cells against H2O2‑induced injury through activation of the PTEN/AKT/mTOR pathway

Abdominal aortic aneurysm (AAA) is a common disease, which is characterized by the apoptosis of vascular smooth muscle cells (VSMCs). In previous years, microRNAs (miRNAs) have been associated with AAA and functionally implicated in the pathogenesis of this disease. However, the role of miRNAs in the apoptosis of VSMCs remains to be fully elucidated. The present study aimed to elucidate the role and mechanism of miRNAs in protecting against hydrogen peroxide (H₂O₂)-induced apoptosis in VSMCs. The expression of miRNAs in peripheral blood from patients diagnosed with AAA was analyzed using a microarray and reverse transcription polymerase chain reaction. A VSMC injury model induced by H₂O₂ was used to determine the potential role of miR-26a against cell injury. Cell viability, cell apoptosis and reactive oxygen species (ROS) generation were determined by a CCK8 assay, flow cytometry and a 2′,7′-DCF diacetate assay, respectively. It was observed that miRNA (miR)-26a (miR-26a-1-5p) was significantly downregulated in peripheral blood samples from patients with AAA. It was revealed that H₂O₂ treatment dose-dependently inhibited cell viability, enhanced apoptosis and induced the production of ROS, which indicated the success of the model establishment. It was also observed that miR-26a was downregulated in the VSMCs following H₂O₂ stimulation. The upregulation of miR-26a attenuated H₂O₂-induced cell injury, as evidenced by the enhancement of cell viability, and inhibition of the activity of caspase-3, apoptosis and ROS production. In addition, phosphatase and tensin homolog (PTEN), a well-known regulator of the AKT/mammalian target of rapamycin (mTOR) pathway, was found to be a direct target of miR-26a in the VSMCs and this was validated using a luciferase reporter assay. Overexpression of PTEN by pcDNA-PTEN plasmids markedly eliminated the protective effects of the overexpression of miR-26a on H₂O₂-induced cell injury. Finally, it was found that miR-26a mediated its anti-apoptotic action by reactivation of the AKT/mTOR pathway, as demonstrated by the upregulation of phosphorylated (p-)AKT and p-mTOR, and the Akt inhibitor API-2 reversing the protective effects on VSMCs mediated by miR-26a. These results indicated that miR-26a protected VSMCs against H₂O₂-induced injury through activation of the PTEN/AKT/mTOR pathway, and miR-26a may be considered as a potential prognostic biomarker and therapeutic target in the treatment of AAA.

Risk of Cardiovascular Disease and Venous Thromboembolism Among Patients With Incident ANCA-Associated Vasculitis: A 20-Year Population-Based Cohort Study

OBJECTIVE

To assess the cardiovascular disease (CVD) and venous thromboembolism (VTE) risks among patients with newly diagnosed antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV).

PATIENTS AND METHODS

A population-based incident AAV cohort of 58 patients diagnosed between 1996 and 2015 in Olmsted County, MN, was identified by medical record review. For each patient, 3 age- and sex-matched non-AAV comparators were randomly selected from the same population and assigned an index date corresponding to the AAV incidence date. Medical records of cases and comparators were reviewed for CVD events, which included cardiac events (coronary artery disease, heart failure, and atrial fibrillation), cerebrovascular accidents (CVA), peripheral vascular disease (PVD), and VTE, which included deep vein thrombosis (DVT) and pulmonary embolism (PE).

RESULTS

Baseline total cholesterol, high-density lipoprotein, and current smoking rate were lower in AAV than in comparators (P=.03, P=.01, and P=.04, respectively), whereas other CVD risk factors and Framingham risk score were not significantly different between the 2 groups. The CVD events developed in 13 patients and 17 comparators, corresponding to a more than 3-fold increased risk (hazard ratio [HR], 3.15; 95% CI, 1.51-6.57). By subtypes, risks were increased for cardiac events (HR, 2.96; 95% CI, 1.42-6.15) and CVA (HR, 8.16; 95% CI, 2.45-27.15), but not for PVD. The HR for VTE was 3.26 (95% CI, 0.84-12.60), significantly increased for DVT (HR, 6.25; 95% CI, 1.16-33.60), but not for PE (HR, 1.33; 95% CI, 0.23-7.54).

CONCLUSION

Despite a similar prevalence of CVD risk factors at baseline, the risk of CVD is more than 3-fold higher and for CVA 8-fold higher in patients with incident AAV than in matched comparator subjects.

Abdominal aortic aneurysm screening: concepts and controversies

Abdominal aortic aneurysms (AAAs) are a leading cause mortality and morbidity but often go undiagnosed until late stages unless imaging is performed. In 2005, the United States Preventive Services Task Force (USPSTF) for the first time recommended one-time ultrasound screening for elderly male smokers and selective screening in other populations. These guidelines were reaffirmed and updated in 2014; a proposal for potential further revisions is now in early planning stages. In this article, we review the past and current USPSTF AAA screening recommendations and techniques for performing optimal screening. Evidence supporting screening and alternative guidelines are also discussed. In addition, emerging concepts and controversies in AAA screening are highlighted, including conflicting data on screening benefits, screening underutilization, inconsistent follow-up recommendations, and the potential for duplicative testing, alternative screening modalities, and clinically significant incidental findings.

Diabetes Reduces Severity of Aortic Aneurysms Depending on the Presence of Cell Division Autoantigen 1 (CDA1)

Diabetes is a negative risk factor for aortic aneurysm, but the underlying explanation for this phenomenon is unknown. We have previously demonstrated that cell division autoantigen 1 (CDA1), which enhances transforming growth factor-β signaling, is upregulated in diabetes. We hypothesized that CDA1 plays a key role in conferring the protective effect of diabetes against aortic aneurysms. Male wild-type, CDA1 knockout (KO), apolipoprotein E (ApoE) KO, and CDA1/ApoE double-KO (dKO) mice were rendered diabetic. Whereas aneurysms were not observed in diabetic ApoE KO and wild-type mice, 40% of diabetic dKO mice developed aortic aneurysms. These aneurysms were associated with attenuated aortic transforming growth factor-β signaling, reduced expression of various collagens, and increased aortic macrophage infiltration and matrix metalloproteinase 12 expression. In the well-characterized model of angiotensin II-induced aneurysm formation, concomitant diabetes reduced fatal aortic rupture and attenuated suprarenal aortic expansion, changes not seen in dKO mice. Furthermore, aortic CDA1 expression was downregulated ∼70% within biopsies from human abdominal aortic aneurysms. The identification that diabetes is associated with upregulation of vascular CDA1 and that CDA1 deletion in diabetic mice promotes aneurysm formation provides evidence that CDA1 plays a role in diabetes to reduce susceptibility to aneurysm formation.

The Relationship Between Serum Interleukin-1α and Asymptomatic Infrarenal Abdominal Aortic Aneurysm Size, Morphology, and Growth Rates

OBJECTIVE/BACKGROUND

In a pilot study, a relationship between abdominal aortic aneurysm (AAA) diameter and serum interleukin (IL)-1α levels was reported, and that endothelial cell (EC) activation in vitro in response to serum from patients with AAA was blocked by anti-IL-1α antibodies. The aim of the present study was to further investigate the relationship between serum IL-1α and asymptomatic infrarenal AAA size, morphology, and growth rates.

METHODS

Serum IL-1α was measured using enzyme linked immunosorbent assay in 101 patients with asymptomatic, infrarenal AAA and related to aneurysm size, morphology, and growth rates.

RESULTS

IL-1α was measured in 101 patients. There was no statistically significant difference in mean age between men and women. IL-1α was detectable in 62.4% of patients; median IL-1α titre was 3.26 pg/mL. There was no statistically significant relationship between IL-1α and maximum AAA antero-posterior diameter as measured by ultrasound (p = .649), AAA morphology (aortic length [p = .394], sac [p = .369], and thrombus volume [p = .629]) as measured on computed tomography, absolute increase in AAA diameter (p = .214), or AAA growth rate (p = .230).

CONCLUSION

IL-1α is detectable in the majority of patients with infrarenal AAA, but the cause and clinical significance of this novel observation remains unknown.