The genetic basis for aortic aneurysmal disease

Contributions of Germline and Somatic Mosaic Genetics to Thoracic Aortic Aneurysms in Nonsyndromic Individuals

BACKGROUND

Thoracic aortic aneurysm (TAA) is associated with significant morbidity and mortality. Although individuals with family histories of TAA often undergo clinical molecular genetic testing, adults with nonsyndromic TAA are not typically evaluated for genetic causes. We sought to understand the genetic contribution of both germline and somatic mosaic variants in a cohort of adult individuals with nonsyndromic TAA at a single center.

METHODS AND RESULTS

One hundred eighty-one consecutive patients <60 years who presented with nonsyndromic TAA at the Massachusetts General Hospital underwent deep (>500×) targeted sequencing across 114 candidate genes associated with TAA and its related functional pathways. Samples from 354 age- and sex-matched individuals without TAA were also sequenced, with a 2:1 matching. We found significant enrichments for germline (odds ratio [OR], 2.44, P=4.6×10-6 [95% CI, 1.67-3.58]) and also somatic mosaic variants (OR, 4.71, P=0.026 [95% CI, 1.20-18.43]) between individuals with and without TAA. Likely genetic causes were present in 24% with nonsyndromic TAA, of which 21% arose from germline variants and 3% from somatic mosaic alleles. The 3 most frequently mutated genes in our cohort were FLNA (encoding Filamin A), NOTCH3 (encoding Notch receptor 3), and FBN1 (encoding Fibrillin-1). There was increased frequency of both missense and loss of function variants in TAA individuals.

CONCLUSIONS

Likely contributory dominant acting genetic variants were found in almost one quarter of nonsyndromic adults with TAA. Our findings suggest a more extensive genetic architecture to TAA than expected and that genetic testing may improve the care and clinical management of adults with nonsyndromic TAA.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Marfan Syndrome: Enhanced Diagnostic Tools and Follow-up Management Strategies

Marfan syndrome (MFS) is a rare inherited autosomic disorder, which encompasses a variety of systemic manifestations caused by mutations in the Fibrillin-1 encoding gene (FBN1). Cardinal clinical phenotypes of MFS are highly variable in terms of severity, and commonly involve cardiovascular, ocular, and musculoskeletal systems with a wide range of manifestations, such as ascending aorta aneurysms and dissection, mitral valve prolapse, ectopia lentis and long bone overgrowth, respectively. Of note, an accurate and prompt diagnosis is pivotal in order to provide the best treatment to the patients as early as possible. To date, the diagnosis of the syndrome has relied upon a systemic score calculation as well as DNA mutation identification. The aim of this review is to summarize the latest MFS evidence regarding the definition, differences and similarities with other connective tissue pathologies with severe systemic phenotypes (e.g., Autosomal dominant Weill-Marchesani syndrome, Loeys-Dietz syndrome, Ehlers-Danlos syndrome) and clinical assessment. In this regard, the management of MFS requires a multidisciplinary team in order to accurately control the evolution of the most severe and potentially life-threatening complications. Based on recent findings in the literature and our clinical experience, we propose a multidisciplinary approach involving specialists in different clinical fields (i.e., cardiologists, surgeons, ophthalmologists, orthopedics, pneumologists, neurologists, endocrinologists, geneticists, and psychologists) to comprehensively characterize, treat, and manage MFS patients with a personalized medicine approach.

Association of MLL3 and TGF-β signaling gene polymorphisms with the susceptibility and prognostic outcomes of Stanford type B aortic dissection : MLL3 with TGF-β signal pathway association with Stanford type B AD

OBJECTIVE

This study aims to investigate the association of lysine methyltransferase 2 C (MLL3) and transforming growth factor β (TGF-β) signaling-related gene polymorphisms with the susceptibility of Stanford type B aortic dissection (AD) and its clinical prognostic outcomes. The methods involved investigating the MLL3 (rs10244604, rs6963460, rs1137721), TGFβ1 (rs1800469), TGFβ2 (rs900), TGFR1 (rs1626340) and TGFR2 (rs4522809) gene polymorphisms. Logistic regression was performed to investigate the association between 7 single nucleotide gene polymorphisms (SNPs) and Stanford type B aortic dissection. The GMDR software was used to analyze gene-gene and gene-environment interactions. The odds ratio (OR) with a 95% confidence interval (CI) was employed to evaluate the association of genes and Stanford type B AD risk.

RESULTS

Genotypes and allele distributions in the case and control groups showed significant differences (P < 0.05). Logistic regression has shown that the Stanford Type B AD risk was highest in individuals with the rs1137721 CT genotype (OR = 4.33, 95% CI = 1.51-12.40). Additionally, WBC, drinking, hypertension, triglycerides (TG), and low-density lipoprotein (LDL-C) were independent risk factors for Stanford Type B AD. Logistic regression showed that the Stanford Type B AD risk was highest in individuals with the MLL3 (rs1137721)-TT + CT and TGFβ1 (rs4522809)-AA genotype (OR = 6.72, 95% CI = 1.56-29.84), and lowest in those with the MLL3 (rs1137721)-CC and TGFβ1 (rs4522809)-AA + GG genotype (OR = 4.38, 95% CI = 0.92-20.83). However, the 55-month median long-term follow-up did not show statistical significance.

CONCLUSION

Carriers of both TT + CT of MLL3 (rs1137721) and AA of TGFβ1 (rs4522809) polymorphisms may be closely related to the development of Stanford type B AD. MLL3 (rs1137721), WBC, and TG/TC were found to be associated with the morbidity of Stanford type B AD. MLL3 (KMT2C) is associated with the TGF-β signaling pathway protein. The risk of Stanford type B AD is related to the interactions of gene-gene and gene-environment.

Reactive oxygen species-induced long intergenic noncoding RNA p21 accelerates abdominal aortic aneurysm formation by promoting secretary smooth muscle cell phenotypes

Whether long noncoding RNAs participate in the formation of abdominal aortic aneurysms (AAAs) through the regulation of SMC phenotypic switching is unknown. lincRNA-p21 induced by reactive oxygen species (ROS) is likely functionally associated with SMC phenotypic switching. We thus investigated the role of lincRNA-p21 in SMC phenotypic switching-associated AAA formation and its underlying mechanisms. An analysis of human and mouse abdominal aortic samples revealed that the lincRNA-p21 levels were significantly higher in AAA tissue. Stimulation with hydrogen peroxide upregulated the expression of lincRNA-p21 in a dose-dependent manner and converted SMCs from a contractile phenotype to a synthetic, proteolytic, and proinflammatory phenotype in vitro. Moreover, lincRNA-p21 promoted fracture of elastic fibres, reconstruction of the vascular wall, and AAA formation in vivo by modulating SMC phenotypic switching in two mouse models of AAA induced by angiotensin II or porcine pancreatic elastase (PPE) perfusion. Using a bioinformatics prediction method and luciferase reporter gene assays, we further proved that lincRNA-p21 sponged miR-204-5p to release the transcriptional activity of Mekk3 and promoted the NF-κB pathway and thereby played a role in the SMC phenotypic switch and AAA formation. The ROS levels were positively correlated with the lincRNA-p21 levels in human and mouse AAA tissues. The knockdown of lincRNA-p21 in a PPE-induced mouse AAA model increased the miR-204-5p levels and reduced the expression of Mekk3, whereas lincRNA-p21 overexpression had the opposite effect. Collectively, the results indicated that ROS-induced lincRNA-p21 sponges miR-204-5p to accelerate synthetic and proinflammatory SMC phenotypes through the Mekk3/NF-κB pathway in AAA formation. Thus, lincRNA-p21 may have therapeutic potential for AAA formation.

Tracking an Elusive Killer: State of the Art of Molecular-Genetic Knowledge and Laboratory Role in Diagnosis and Risk Stratification of Thoracic Aortic Aneurysm and Dissection

The main challenge in diagnosing and managing thoracic aortic aneurysm and dissection (TAA/D) is represented by the early detection of a disease that is both deadly and “elusive”, as it generally grows asymptomatically prior to rupture, leading to death in the majority of cases. Gender differences exist in aortic dissection in terms of incidence and treatment options. Efforts have been made to identify biomarkers that may help in early diagnosis and in detecting those patients at a higher risk of developing life-threatening complications. As soon as the hereditability of the TAA/D was demonstrated, several genetic factors were found to be associated with both the syndromic and non-syndromic forms of the disease, and they currently play a role in patient diagnosis/prognosis and management-guidance purposes. Likewise, circulating biomarker could represent a valuable resource in assisting the diagnosis, and several studies have attempted to identify specific molecules that may help with risk stratification outside the emergency department. Even if promising, those data lack specificity/sensitivity, and, in most cases, they need more testing before entering the “clinical arena”. This review summarizes the state of the art of the laboratory in TAA/D diagnostics, with particular reference to the current and future role of molecular-genetic testing.

The Impact of Abdominal Aortic Aneurysm on Cardiovascular Diseases

Cardiovascular diseases (CVDs) including myocardial infarction (MI) and stroke are often diagnosed in patients with abdominal aortic aneurysm (AAA). However, little has been reported regarding the incidence.Patients with AAA were selected from the National Health Insurance system in South Korea between 2009 and 2015. A total of 10,822 participants with a new diagnosis of AAA were included. Propensity score matching by age and sex with patients in whom AAA was not diagnosed was used to select the control group of 32,466 participants. Primary endpoints included the diagnosis of CVD and death. Cox proportional hazard models were used to compare the risk of disease incidence.The incidence of CVD was 16.573 per 1,000 person-years in the AAA group, which was higher than that of the control group's 9.30 per 1,000 person-years. The incidence of MI (hazard ratio [HR], 1.7; 95% confidence interval [CI], 1.479-1.953), stroke (HR, 1.629; 95% CI, 1.443-1.839), and CVD (HR, 1.672; 95% CI, 1.522-1.835) was significantly higher in patients with AAA. Mortality rate was also elevated in the AAA group (HR, 2.544; 95% CI, 2.377-2.722).The incidence of CVD was significantly more frequent in patients with AAA. The AAA group had consistently higher risks regarding CVD and mortality than the control group.

Identification of novel genetic biomarkers and treatment targets for arteriosclerosis-related abdominal aortic aneurysm using bioinformatic tools

A large number of epidemiological studies have confirmed that arteriosclerosis (AS) is a risk factor for abdominal aortic aneurysm (AAA). However, the relationship between AS and AAA remains controversial. The objective of this work is to better understand the association between the two diseases by identifying the co-differentially expressed genes under both pathological conditions, so as to identify potential genetic biomarkers and treatment targets for atherosclerosis-related aneurysms. Differentially-expressed genes (DEGs) shared by both AS and AAA patients were identified by bioinformatics analyses of Gene Expression Omnibus (GEO) datasets GSE100927 and GSE7084. These DEGs were then subjected to bioinformatic analyses of protein-protein interaction (PPI), Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Finally, the identified hub genes were further validated by qRT-PCR in AS (n = 4), AAA (n = 4), and healthy (n = 4) individuals. Differential expression analysis revealed a total of 169 and 37 genes that had increased and decreased expression levels, respectively, in both AS and AAA patients compared with healthy controls. The construction of a PPI network and key modules resulted in the identification of five hub genes (SPI1, TYROBP, TLR2, FCER1G, and MMP9) as candidate diagnostic biomarkers and treatment targets for patients with AS-related AAA. AS and AAA are indeed correlated; SPI1, TYROBP, TLR2, FCER1G and MMP9 genes are potential new genetic biomarkers for AS-related AAA.

Investigating the Link between Alpha-1 Antitrypsin Deficiency and Abdominal Aortic Aneurysms

BACKGROUND

Alpha-1-Antitrypsin (AAT) is one of the major plasmatic protease inhibitors. In the last decade, an association between Alpha-1-Antitrypsin Deficiency (AATD) and Abdominal Aortic Aneurysms (AAA) has been hypothesized. Multiple factors may be involved in AAA's etiopathogenesis, and an underlying structural defect of the extracellular matrix (ECM) is always present. AATD could be a reasonable risk factor for AAA because it is related to protease/antiprotease imbalance and enhanced ECM degradation of the vessel wall.

METHODS

We performed genotyping of 138 patients hospitalized in the Vascular Surgery Division of the ASST-Spedali Civili di Brescia, Italy, for nontraumatic rupture of AAA. The second purpose was to observe the distribution of main nongenetic risk factors for AAA between patients with and without AATD.

RESULTS

Out of 138 patients, 22 were found with AATD: 16 MS, 1 SS, 3 MZ, and 2 with a new rare AAT variant. When compared to the general Italian population, our cohort's frequency of deficient S allele was significantly higher (7.8 vs. 2.2% respectively, P < 0.01), whereas the deficient Z allele was similar (1.1 vs. 1.3% respectively, P > 0.05). Although we found no differences in age, gender, hypertension, diabetes, and smoke habits between AAA patients with and without AATD, hyperlipidemia was significantly less frequent in patients with AATD (46.4 vs. 12.5% respectively, P < 0.05).

CONCLUSIONS

In our AAA patients' cohort, the S allele frequency was higher than in the general Italian population. Our results support the hypothesis that AATD might be a risk factor for AAA.

Matrix metalloproteinase 9 a potential major player connecting atherosclerosis and osteoporosis in high fat diet fed rats

Background

Cardiovascular diseases (CVD) represent one of the major sequelae of obesity. On the other hand, the relationship between bone diseases and obesity remains unclear. An increasing number of biological and epidemiological studies suggest the presence of a link between atherosclerosis and osteoporosis, however, the precise molecular pathways underlying this close association remain poorly understood. The present work thus aimed to study Matrix Metalloproteinase 9 (MMP-9), as a proposed link between atherosclerosis and osteoporosis in high fat diet fed rats.

Methods and findings

40 rats were randomly divided into 4 groups: control, untreated atherosclerosis group, atherosclerotic rats treated with carvedilol (10mg/kg/d) and atherosclerotic rats treated with alendronate sodium (10mg/kg/d). After 8 weeks, blood samples were collected for estimation of Lipid profile (Total cholesterol, HDL, TGs), inflammatory markers (IL-6, TNF-α, CRP and NO) and Bone turnover markers (BTMs) (Alkaline phosphatase, osteocalcin and pyridinoline). Rats were then euthanized and the aortas and tibias were dissected for histological examination and estimation of MMP-9, N-terminal propeptide of type I procollagen (PINP), C-terminal telopeptide of type I collagen (CTX) and NF-kB expression. Induction of atherosclerosis via high fat diet and chronic stress induced a significant increase in BTMs, inflammatory markers and resulted in a state of dyslipidaemia. MMP-9 has also shown to be significantly increased in the untreated atherosclerosis rats and showed a significant correlation with all measured parameters. Interestingly, Carvedilol and bisphosphonate had almost equal effects restoring the measured parameters back to normal, partially or completely.

Conclusion

MMP-9 is a pivotal molecule that impact the atherogenic environment of the vessel wall. A strong cross talk exists between MMP-9, cytokine production and macrophage function. It also plays an important regulatory role in osteoclastogenesis. So, it may be a key molecule in charge for coupling CVD and bone diseases in high fat diet fed rats. Therefore, we suggest MMP-9 as a worthy molecule to be targeted pharmacologically in order to control both conditions simultaneously. Further studies are needed to support, to invest and to translate this hypothesis into clinical studies and guidelines.

Variants of Focal Adhesion Scaffold Genes Cause Thoracic Aortic Aneurysm

RATIONALE

Thoracic aortic aneurysm (TAA) leads to substantial mortality worldwide. Familial and syndromic TAAs are highly correlated with genetics. However, the incidence of sporadic isolated TAA (iTAA) is much higher, and the genetic contribution is not yet clear.

OBJECTIVE

Here, we examined the genetic characteristics of sporadic iTAA.

METHODS AND RESULTS

We performed a genetic screen of 551 sporadic iTAA cases and 1071 controls via whole-exome sequencing. The prevalence of pathogenic mutations in known causal genes was 5.08% in the iTAA cohort. We selected 100 novel candidate genes using a strict strategy, and the suspected functional variants of these genes were significantly enriched in cases compared with controls and carried by 60.43% of patients. We found more severe phenotypes and a lower proportion of hypertension in cases with pathogenic mutations or suspected functional variants. Among the candidate genes, Testin (TES), which encodes a focal adhesion scaffold protein, was identified as a potential TAA causal gene, accounting for 4 patients with 2 missense variants in the LIM1 domain (c.751T>C encoding p.Y251H; c.838T>C encoding p.Y280H) and highly expressed in the aorta. The 2 variants led to a decrease in TES expression. The thoracic aorta was spontaneously dilated in the Tes^Y249H knock-in and Tes^-/- mice. Mechanistically, the p.Y249H variant or knockdown of TES led to the repression of vascular smooth muscle cell contraction genes and disturbed the vascular smooth muscle cell contractile phenotype. Interestingly, suspected functional variants of other focal adhesion scaffold genes, including TLN1 (Talin-1) and ZYX (zyxin), were also significantly enriched in patients with iTAA; moreover, their knockdown resulted in decreased contractility of vascular smooth muscle cells.

CONCLUSIONS

For the first time, this study revealed the genetic landscape across iTAA and showed that the focal adhesion scaffold genes are critical in the pathogenesis of iTAA.

Association of C-Reactive Protein-to-Albumin Ratio With the Presence and Progression of Abdominal Aortic Aneurysm

Aortic dilatation due to inflammation may lead to an increase in C-reactive protein (CRP) levels. We investigated the possible relationship between CRP-to-albumin ratio (CAR) and presence and progression of abdominal aortic aneurysms (AAAs). The study included 150 patients previously diagnosed with AAA (diameter 40-54 mm) and 100 normal controls. Clinical and laboratory parameters and maximal cross-sectional AAA diameters (measured by computed tomography angiography) were obtained from all participants at baseline assessment as well as after 1 year for those with an AAA. The patients with AAA had significantly higher serum CAR compared with controls at baseline (P < .001). Increased serum CAR was found to be an independent predictor of the presence of AAA (odds ratio: 3.162, 95% CI: 1.690-5.126, P = .001) after multivariate logistic regression analysis. There was a significant increase in aortic diameter and CAR after 1 year in the patients with AAA (P < .001; P = .003); a significant correlation was found between changes in the diameter of AAAs and CAR (r = 0.414; P = .005). Serum CAR may be useful as an inflammatory biomarker for the presence and progression of AAA.

Association of Intracranial Aneurysms With Aortic Aneurysms in 125 Patients With Fusiform and 4253 Patients With Saccular Intracranial Aneurysms and Their Family Members and Population Controls

Background

Varying degrees of co‐occurrence of intracranial aneurysms (IA) and aortic aneurysms (AA) have been reported. We sought to compare the risk for AA in fusiform intracranial aneurysms (fIA) and saccular intracranial aneurysms (sIA) disease and evaluate possible genetic connection between the fIA disease and AAs. Additionally, the characteristics and aneurysms of the fIA and sIA patients were compared.

Methods and Results

The Kuopio Intracranial Aneurysm Database includes all 4253 sIA and 125 fIA patients from its Eastern Finnish catchment population, and 13 009 matched population controls and 18 455 first‐degree relatives to the IA patients were identified, and the Finnish national registers were used to identify the individuals with AA. A total of 33 fIA patients were studied using an exomic gene panel of 37 genes associated with AAs. Seventeen (14.4%) fIA patients and 48 (1.2%) sIA patients had a diagnosis of AA. Both fIA and sIA patients had AAs significantly more often than their controls (1.2% and 0.5%) or relatives (0.9% and 0.3%). In a competing risks Cox regression model, the presence of fIA was the strongest risk factor for AA (subdistribution hazard ratio 7.6, 95% CI 3.9–14.9, P<0.0005). One likely pathogenic variant in COL5A2 and 3 variants of unknown significance were identified in MYH11,COL11A1, and FBN1 in 4 fIA patients.

Conclusions

The prevalence of AAs is increased slightly in sIA patients and significantly in fIA patients. fIA patients are older and have more comorbid diseases than sIA patients but this alone does not explain their clinically significant AA risk.

Angiotensin II Signal Transduction: An Update on Mechanisms of Physiology and Pathophysiology

The renin-angiotensin-aldosterone system plays crucial roles in cardiovascular physiology and pathophysiology. However, many of the signaling mechanisms have been unclear. The angiotensin II (ANG II) type 1 receptor (AT₁R) is believed to mediate most functions of ANG II in the system. AT₁R utilizes various signal transduction cascades causing hypertension, cardiovascular remodeling, and end organ damage. Moreover, functional cross-talk between AT₁R signaling pathways and other signaling pathways have been recognized. Accumulating evidence reveals the complexity of ANG II signal transduction in pathophysiology of the vasculature, heart, kidney, and brain, as well as several pathophysiological features, including inflammation, metabolic dysfunction, and aging. In this review, we provide a comprehensive update of the ANG II receptor signaling events and their functional significances for potential translation into therapeutic strategies. AT₁R remains central to the system in mediating physiological and pathophysiological functions of ANG II, and participation of specific signaling pathways becomes much clearer. There are still certain limitations and many controversies, and several noteworthy new concepts require further support. However, it is expected that rigorous translational research of the ANG II signaling pathways including those in large animals and humans will contribute to establishing effective new therapies against various diseases.

Risk Factors for Abdominal Aortic Aneurysm in Population-Based Studies: A Systematic Review and Meta-Analysis

Abdominal aortic aneurysm (AAA) represents an important public health problem with a prevalence between 1.3% and 12.5%. Several population-based randomized trials have evaluated ultrasound screening for AAA providing evidence of a reduction in aneurysm-related mortality in the screened population. The aim of our study was to perform a systematic review and meta-analysis of the risk factors for AAA. We conducted a systematic review of observational studies and we performed a meta-analysis that evaluated the following risk factors: gender, smoking habits, hypertension, coronary artery disease and family history of AAA. Respect to a previous a meta-analysis we added the funnel plot to examine the effect sizes estimated from individual studies as measure of their precision; sensitivity analysis to check the stability of study findings and estimate how the overall effect size would be modified by removal of one study; cumulative analysis to evaluate the trend between studies in relation to publication year. Abdominal aortic aneurysm prevalence is higher in smokers and in males. On the other hand, while diabetes is a risk factor for many cardiovascular diseases, it is not a risk factor for AAA. In addition, it is important to underline that all countries, where AAA screening was set up, had high income level and the majority belong to Western Europe (United Kingdom, Sweden, Italy, Poland, Spain and Belgium). Abdominal aortic aneurysm screening is fundamental for public health. It could avoid deaths, ruptures, and emergency surgical interventions if abdominal aortic aneurysm was diagnosed early in the population target for screening.

Saphenous vein graft aneurysm formation in a patient with idiopathic multiple aneurysms

True aneurysmal vein graft dilation is rare, and its etiology remains speculative. However, systemic dilation diathesis is regarded as a risk factor. We herein report a case of a rapidly expanding aneurysm in a great saphenous vein graft, resulting in distal malperfusion in a patient who had previously undergone open repair of multiple popliteal artery aneurysms. After an unsuccessful endovascular intervention, the dilated section was eventually replaced by a reversed segment of the contralateral great saphenous vein. Subsequent whole-exome sequencing identified no relevant mutations. This case provides further evidence that aneurysmal disease may be associated with systemic dilation diathesis.

The effects of the elastin polymorphisms on carotid intima-media thickness in women aged 30 - 70

[Purpose]

Elastin is one of the major determinants of arterial distensibility of large blood vessels that forms the principal component of elastic fibers from the media of arteries. However, the association between elastin(ELN) genotype and vascular function is still unclear.

[Methods]

120women were recruited from the Saha-gu (Busan, Korea) Community Center. Measurements of body composition and vascular function included carotid intima-media thickness (CIMT), carotid artery luminal diameter (CLD), minimum (diastolic) artery luminal diameter (CLD_min) and maximum (systolic) artery luminal diameter (CLD_max). Genotyping for the ELN (rs 2071307) polymorphism was performed using the TaqMan approach. ELN gene distribution of subjects were in the Hardy-Weinberg equilibrium (p=0.402).

[Results]

The relative CIMT differed significantly among the ELN genotypes. And not significant differences in CLD and CIMT/CLD ratio, but AA genotype was tended higher than other genotypes (AG and GG). The relative CIMT and CLD min differed significantly between the ELN alleles. And not significant differences in CLD max and CIMT/CLD ratio, but A allele was tended higher than G allele.

[Conclusion]

These results suggest that ELN gene polymorphism might be used a one of the genetic determinants of vascular disease in both pre- and postmenopausal women.

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.

Impact of abdominal aortic aneurysm screening on quality of life

BACKGROUND

Screening for abdominal aortic aneurysm (AAA) is known to reduce AAA-related mortality; however, the psychological impact of population AAA screening is unclear. The aim was to assess the impact of AAA diagnosis on quality of life (QoL) using data from an established AAA screening programme.

METHODS

Mental and physical QoL scores for men diagnosed with AAA through participation in the English and Welsh AAA screening programmes were compared with no-AAA controls. Participants were identified through the United Kingdom Aneurysm Growth Study (UKAGS), a nationwide prospective cohort study of men with an AAA of less than 55 mm diagnosed through voluntary participation in screening. The UKAGS participants completed QoL questionnaires at the time of screening and annually thereafter.

RESULTS

A transient reduction in mental QoL scores was observed following the diagnosis of AAA, returning to baseline levels after 12 months. Physical QoL remained consistently lower in the AAA cohort. Participants thought about their AAA and the AAA growth progressively less 12 months after the initial screening diagnosis. AAA growth rate had no influence over QoL parameters.

DISCUSSION

This study suggests that screening for AAA does reduce mental QoL; however, this effect is transient (less than 12 months). Men diagnosed with AAA have a consistently worse physical QoL compared with controls.

Characterization of SMAD2 Activation in Human Thoracic Aortic Aneurysm

Objective: Thoracic aortic aneurysm (TAA) reflects the local expansion of the thoracic aorta; the underlying causal molecular mechanism of TAA is not well understood. Recent studies have shown the importance of transforming growth factor beta (TGFβ) signaling in Marfan and Loeys–Dietz syndromes; however, its role in non-familial, non-syndromic TAA remains unclear.

Materials and Methods: We performed histochemical and immunohistochemical analyses for activated (phosphorylated) SMAD2 (P-SMAD2) as an indicator of TGFβ signaling activities in the ascending TAA tissue as well as in the ascending aortic tissue with a normal diameter obtained from 7 patients without any clinical findings suggesting familial or syndromic TAA.

Results: TAA samples showed a higher P-SMAD2-positive area than samples with a normal diameter. P-SMAD2 signal was higher in the outer zone of the aortic and TAA walls. Within the TAA tissue, P-SMAD2 staining showed the following two distinct patterns: layer-like staining at the border of the medial layer and the thickened intima and a spot-like staining within the medial layer surrounding the microvessels.

Conclusion: These findings suggested that TGFβ signaling is activated in several distinct histopathological contexts in TAA, suggesting a complex role of TGFβ.

ADAB2IPgenotype: sex interaction is associated with abdominal aortic aneurysm expansion

A faster expansion rate of abdominal aortic aneurysm (AAA) increases the risk of rupture. Women are at higher risk of rupture than men, but the mechanisms underlying this increased risk are unknown. We investigated whether genetic variants that influence susceptibility for AAA (CDKN2A-2B,SORT1,DAB2IP,LRP1andLDLR) are associated with AAA expansion and whether these associations differ by sex in 650 patients with AAA (mean age 70±8 years, 17% women) enrolled in the Mayo Clinic Vascular Disease Biorepository. Women had a mean aneurysm expansion 0.41 mm/year greater than men after adjustment for baseline AAA size. In addition to baseline size, mean arterial pressure (MAP), non-diabetic status,SORT1-rs599839[G] andDAB2IP-rs7025486[A] were associated with greater aneurysm expansion (all p<0.05). The associations of MAP and rs599839[G] were similar in both sexes, while the associations of baseline size, pulse pressure (PP) and rs7025486[A] were stronger in women than men (all p-sexinteraction≤0.02). A three-way interaction of PP*sex* rs7025486[A] was noted in a full-factorial analysis (p=0.007) independent of baseline size and MAP. In the high PP group (≥median), women had a mean growth rate 0.68 mm/year greater per [A] of rs7025486 than men (p-sexinteraction=0.003), whereas there was no difference in the low PP group (p-sexinteraction=0.8). We demonstrate that variantsDAB2IP-rs7025486[A] andSORT1-rs599839[G] are associated with AAA expansion. The association of rs7025486[A] is stronger in women than men and amplified by high PP, contributing to sex differences in aneurysm expansion.

Application of Metabolic Profiling to Abdominal Aortic Aneurysm Research

Abdominal aortic aneurysm (AAA) is a complex disease posing diagnostic and therapeutic challenges. Metabonomics may aid in the diagnosis of AAA, determination of individualized risk, discovery of therapeutic targets, and improve understanding of pathogenesis. A systematic review of the diversity and outcomes of existing AAA metabonomic research has been performed. Original research studies applying metabonomics to human aneurysmal disease are included. Seven relevant articles were identified: four studies were based on plasma/serum metabolite profiling, and three studies examined aneurysmal tissue. Aminomalonic acid, guanidinosuccinic acid, and glycerol emerge as potential plasma biomarkers of large aneurysm. Lipid profiling improves predictive models of aneurysm presence. Patterns of metabolite variation associated with AAA relate to carbohydrate and lipid metabolism. Perioperative perturbations in metabolites suggest differential systemic inflammatory responses to surgery, generating hypotheses for adjunctive perioperative therapy. Significant limitations include small study sizes, lack of correction for multiple testing false discovery rates, and single time-point sampling. Metabolic profiling carries the potential to identify biomarkers of AAA and elucidate pathways underlying aneurysmal disease. Statistically and methodologically robust studies are required for validation, addressing the hiatus in understanding mechanisms of aneurysm growth and developing effective treatment strategies.

Postmortem genetic testing should be recommended in sudden cardiac death cases due to thoracic aortic dissection

BACKGROUND

Acute thoracic aortic dissections and ruptures, the main life-threatening complications of the corresponding aneurysms, are an important cause of sudden cardiac death. Despite the usefulness of the molecular diagnosis of these conditions in the clinical setting, the corresponding forensic field remains largely unexplored. The main goal of this study was to explore and validate a new massive parallel sequencing candidate gene​ assay as a diagnostic tool for acute thoracic aortic dissection autopsy cases.

MATERIALS AND METHODS

Massive parallel sequencing of 22 thoracic aortic disease candidate genes performed in 17 cases of thoracic aortic dissection using AmpliSeq and Ion Proton technologies. Genetic variants were filtered by location, type, and frequency at the Exome Aggregation Consortium and an internal database and further classified based on the American College of Medical Genetics and Genomics (ACMG) recommendations published in 2015. All prioritized results were confirmed by traditional sequencing.

RESULTS

From the total of 10 potentially pathogenic genetic variants identified in 7 out of the 17 initial samples, 2 of them were further classified as pathogenic, 2 as likely pathogenic, 1 as possibly benign, and the remaining 5 as variants of uncertain significance, reaching a molecular autopsy yield of 23%, approximately.

CONCLUSIONS

This massive parallel sequencing candidate gene approach proved useful for the molecular autopsy of aortic dissection sudden cardiac death cases and should therefore be progressively incorporated into the forensic field, being especially beneficial for the anticipated diagnosis and risk stratification of any other family member at risk of developing the same condition.

Abdominal aortic aneurysm-an independent disease to atherosclerosis?

Atherosclerosis and abdominal aortic aneurysms (AAAs) are multifactorial and polygenic diseases with known environmental and genetic risk factors that contribute toward disease development. Atherosclerosis represents an important independent risk factor for AAA, as people with AAA often have atherosclerosis. Studies have shown that comorbidity is usually between ~25% and 55%, but it is still not fully known whether this association is causal or a result of common shared risk profiles. Most recent epidemiological, clinical, and biological evidence suggests that the two pathologies are more distinct than traditionally thought. For instance diabetes mellitus, hypercholesterolemia, and obesity are high risk for atherosclerosis development but are not as pronounced in AAA, whereas smoking, gender, and ethnicity are particularly high risk for AAA but less so for atherosclerosis. In addition, genetic and epigenetic studies have identified independent risk loci involved in AAA susceptibility that are not associated with other cardiovascular diseases, and research on important common cardiovascular biomarkers has illustrated discrepancies in those with AAA.

Prevalence of abdominal aortic aneurysms and its relation with cardiovascular risk stratification: protocol of the Risk of Cardiovascular diseases and abdominal aortic Aneurysm in Varese (RoCAV) population based study

BACKGROUND

Recent meta-analyses suggested that screening program for abdominal aortic aneurysms (AAA) in 65-year old males is cost-effective at prevalence of about 1%. Since some events occur also in females and among the youngers, screening could be feasible among those at higher risk, such as smokers or individuals with a family history of AAA. The RoCAV (Risk of Cardiovascular diseases and abdominal aortic Aneurysms in Varese) Project is a population-based study aimed to evaluate AAA prevalence in Northern Italy in males over-65 years as well as among females and younger males, and to identify new markers for risk stratification by collecting a large set of CVD risk factors. The aims of the project are: (i) cross-sectional evaluation of AAA prevalence (ii); evaluation of standard CVD risk score as criteria for selecting subgroup at higher risk to be included in a screening program; (iii) identification of new risk markers and risk score algorithm for AAA and CVD risk stratification; (iv) cost-effective evaluation during the follow-up.

METHODS

Males aged 50-75 years and females aged 60-75 years, resident in the city of Varese (Lombardy Region), were randomly selected from the civil registry. Among 5198 successfully invited, 3777 subjects accepted to participate and were finally recruited (participation rate 63.8%) from June 2013 to May 2016. Trained operators administered a computerized anamnestic questionnaire, measured anthropometric parameters (BMI, body circumferences, skinfolds), blood pressure, ankle-brachial index, pulse wave velocity and performed abdominal aortic ultrasound scan, ECG and spirometry. All methods were internationally validated. A blood sample was collected and stored in biobank. A follow-up will be carried out through linkage with electronic records.

DISCUSSION

Participation rate and data quality assessment were as expected and will reasonably allow to reach the project aims. The expected impact in public health of the RoCAV project will be the potential implementation of a AAA screening program to the whole region as well as the formulation of new criteria for risk assessment of AAA and CVD.

MMP-2 Isoforms in Aortic Tissue and Serum of Patients with Ascending Aortic Aneurysms and Aortic Root Aneurysms

OBJECTIVE

The need for biological markers of aortic wall stress and risk of rupture or dissection of ascending aortic aneurysms is obvious. To date, wall stress cannot be related to a certain biological marker. We analyzed aortic tissue and serum for the presence of different MMP-2 isoforms to find a connection between serum and tissue MMP-2 and to evaluate the potential of different MMP-2 isoforms as markers of high wall stress.

METHODS

Serum and aortic tissue from n = 24 patients and serum from n = 19 healthy controls was analyzed by ELISA and gelatin zymography. 24 patients had ascending aortic aneurysms, 10 of them also had aortic root aneurysms. Three patients had normally functioning valves, 12 had regurgitation alone, eight had regurgitation and stenosis and one had only stenosis. Patients had bicuspid and tricuspid aortic valves (9/15). Serum samples were taken preoperatively, and the aortic wall specimen collected during surgical aortic repair.

RESULTS

Pro-MMP-2 was identified in all serum and tissue samples. Pro-MMP-2 was detected in all tissue and serum samples from patients with ascending aortic/aortic root aneurysms, irrespective of valve morphology or other clinical parameters and in serum from healthy controls. We also identified active MMP-2 in all tissue samples from patients with ascending aortic/aortic root aneurysms. None of the analyzed serum samples revealed signals relatable to active MMP-2. No correlation between aortic tissue total MMP-2 or tissue pro-MMP-2 or tissue active MMP-2 and serum MMP-2 was found and tissue MMP-2/pro-MMP-2/active MMP-2 did not correlate with aortic diameter. This evidence shows that pro-MMP-2 is the predominant MMP-2 species in serum of patients and healthy individuals and in aneurysmatic aortic tissue, irrespective of aortic valve configuration. Active MMP-2 species are either not released into systemic circulation or not detectable in serum. There is no reliable connection between aortic tissue-and serum MMP-2 isoforms, nor any indication that pro-MMP-2 functions as a common marker of high aortic wall stress.

PRKG1 and genetic diagnosis of early-onset thoracic aortic disease

BACKGROUND

The 20% of thoracic aortic aneurysms and dissections independent from the main connective tissue syndromes and expected to be familial has gained importance over the past years. The more frequent pattern of inheritance of these nonsyndromic cases is autosomal dominant with incomplete penetrance and variable expression. Although many candidate genes exist, unresolved familial cases suggest still unravelled genetic variation. The main purpose of this study was to establish the genetic diagnosis of one of those.

MATERIALS AND METHODS

To begin with, we applied a candidate gene approach based on both traditional and a customized massive parallel sequencing panel, followed by Illumina HiSeq 2000 whole exome sequencing of four family members affected by early-onset thoracic aortic disease and two unaffected relatives. We prioritized whole exome sequencing results based on variant location, type and frequency in general population databases and performed segregation analysis in 14 family members using traditional sequencing.

RESULTS

After the negative results we obtained with candidate gene approaches, the analysis and prioritization of whole exome sequencing results brought out the heterozygote c.530G>A:p.Arg177Gln PRKG1 variant (NM_001098512), located in one of the aortic smooth muscle cell contractile apparatus genes. This candidate variant segregated with thoracic aortic disease, as it was present in seven affected and absent in five unaffected family members, further supporting its causality.

CONCLUSIONS

This was the second time PRKG1 was associated with thoracic aortic disease, highlighting and reaffirming it as a strong candidate for gene-based diagnosis of nonsyndromic early-onset cases.

Meta-analysis of Outcomes Following Aneurysm Repair in Patients with Synchronous Intra-abdominal Malignancy

OBJECTIVES

The management of concomitant intra-abdominal malignancy (IAM) and abdominal aortic aneurysm (AAA) remains a challenge, even though malignancy is common in an elderly population. By means of systematic review and meta-analysis, the aim was to investigate outcomes in patients undergoing open (OAR) or endovascular AAA repair (EVAR) that have a concomitant malignancy.

METHODS

A systematic literature review was performed (Medline and EMBASE databases) to identify all series reporting outcomes of AAA repair (OAR or EVAR) in patients with concomitant IAM. Meta-analysis was applied to assess mortality and major morbidity at 30 days and long term.

RESULTS

The literature review identified 36 series (543 patients) and the majority (18 series) reported on patients with colorectal malignancy and AAA. Mean weighted mortality for OAR at 30 days was 11% (95% CI: 6.6% to 17.9%); none of the EVAR patients died peri-operatively. The weighted 30-day major complication rate for EVAR was 20.4% (10.0-37.4%) and for OAR it was 15.4% (7.0-30.8%). Most patients had their AAA and malignancy treated non-simultaneously (56.6%, 95% CI, 42.1-70.1%). In the EVAR cohort, three patients (4.6%) died at last follow-up (range 24-64 months). In the OAR cohort 23 (10.6%) had died at last follow up (range from 4 to 73 months).

CONCLUSION

In this meta-analysis, OAR was associated with significant peri-operative mortality in patients with an IAM. EVAR should be the first-line modality of AAA repair. The majority of patients were not treated simultaneously for the two pathologies, but further investigation is necessary to define the optimal timing for each procedure and malignancy.

Aortic dissection

Aortic dissection is a life-threatening condition caused by a tear in the intimal layer of the aorta or bleeding within the aortic wall, resulting in the separation (dissection) of the layers of the aortic wall. Aortic dissection is most common in those 65-75 years of age, with an incidence of 35 cases per 100,000 people per year in this population. Other risk factors include hypertension, dyslipidaemia and genetic disorders that involve the connective tissue, such as Marfan syndrome. Swift diagnostic confirmation and adequate treatment are crucial in managing affected patients. Contemporary management is multidisciplinary and includes serial non-invasive imaging, biomarker testing and genetic risk profiling for aortopathy. The choice of approach for repairing or replacing the damaged region of the aorta depends on the severity and the location of the dissection and the risks of complication from surgery. Open surgical repair is most commonly used for dissections involving the ascending aorta and the aortic arch, whereas minimally invasive endovascular intervention is appropriate for descending aorta dissections that are complicated by rupture, malperfusion, ongoing pain, hypotension or imaging features of high risk. Recent advances in the understanding of the underlying pathophysiology of aortic dissection have led to more patients being considered at substantial risk of complications and, therefore, in need of endovascular intervention rather than only medical or surgical intervention.

Nonsyndromic Thoracic Aortic Aneurysm and Dissection: Outcomes With Marfan Syndrome Versus Bicuspid Aortic Valve Aneurysm

BACKGROUND

Genetic aortopathy (GA) underlies thoracic aortic aneurysms (TAA) in younger adults. Comparative survival and predictors of outcomes in nonsyndromic TAA (NS-TAA) are incompletely defined compared to Marfan syndrome (MFS) and bicuspid aortic valve (BAV).

OBJECTIVES

The study sought to compare survival and clinical outcomes for individuals with NS-TAA, MFS, and BAV.

METHODS

From 1988 to 2014, all patients presenting with GA 16 to 60 years of age were enrolled in a prospective study of clinical outcomes. Risk factors for death and aortic dissection were identified by Cox proportional hazards modeling and a mortality risk score developed.

RESULTS

Diagnosis of GA was made for 760 patients (age 36.9 ± 13.6 years, 26.8% female; NS-TAA, n = 311; MFS, n = 221; BAV, n = 228). MFS patients were younger than NS-TAA and BAV. Presentation with aortic dissection was more common for NS-TAA than MFS or BAV. The 687 patients surviving >30 days after presentation were followed for a median of 7 years. Calculated 10-year mortality was 7.8% for NS-TAA, 8.7% for MFS, and 3.5% for BAV (NS-TAA and MFS vs. BAV p <0.05). Factors associated with all-cause mortality were MFS (p = 0.04), age at presentation, and family history of dissection.

CONCLUSIONS

Clinical outcomes for MFS and NS-TAA are similar but worse than BAV. Independent predictors of mortality, including family history of aortic dissection and age, can be included in an Aortopathy Mortality Risk Score to predict survival. Management of NS-TAA, including surgical intervention, should be similar to that of MFS.

Familial non-syndromal thoracic aortic aneurysms and dissections - Incidence and family screening outcomes

BACKGROUND

Non-syndromal thoracic aortic aneurysm and dissection (ns-TAAD) is a genetic aortopathy, with uncertain incidence. This study documented the incidence of ns-TAAD and outcomes of family screening over 15years.

METHODS

Consecutive series of 2385 patients with aortic disease in prospective registry (2000 to 2014), including 675 undergoing surgery. Diagnosis of ns-TAAD included family history, aortic imaging, tissue pathology and mutation testing. Screening was offered to relatives of ns-TAAD probands, with follow-up for affected individuals.

RESULTS

There were 270 ns-TAAD probands (74% males), including 116 (43%) presenting with aortic dissection. Among surgical cases, a diagnosis of ns-TAAD was established for 116 (17%). Age of probands was 50.4±14.1years, with aortic diameter of 51±12mm. Screening of 581 at-risk relatives identified 216 new ns-TAAD cases (detection rate=37%). Among 71 probands with known family history, screening identified 130 new affected relatives and among 53 probands with no family history, screening identified 86 new affected relatives. Mean age of new affected relatives at diagnosis was 44±18years, with aortic diameter of 42±7mm, including 42 with diameter>50mm. Ten-year mortality was similar for probands without dissection (7.7±3.1%) and new affected relatives (11.4±4.0%) but greater for probands surviving initial dissection (27.6±7.8%, p=0.003).

CONCLUSIONS

Up to 1 in 6 patients undergoing aortic surgery have features of ns-TAAD, frequently presenting as aortic dissection but at later age than other genetic aortopathies. Family screening identifies affected relatives in up to half of ns-TAAD probands, many of whom already have significant aortic dilatation.

A Methodology for Concomitant Isolation of Intimal and Adventitial Endothelial Cells from the Human Thoracic Aorta

BACKGROUND

Aortic diseases are diverse and involve a multiplicity of biological systems in the vascular wall. Aortic dissection, which is usually preceded by aortic aneurysm, is a leading cause of morbidity and mortality in modern societies. Although the endothelium is now known to play an important role in vascular diseases, its contribution to aneurysmal aortic lesions remains largely unknown. The aim of this study was to define a reliable methodology for the isolation of aortic intimal and adventitial endothelial cells in order to throw light on issues relevant to endothelial cell biology in aneurysmal diseases.

METHODOLOGY/PRINCIPAL FINDINGS

We set up protocols to isolate endothelial cells from both the intima and the adventitia of human aneurysmal aortic vessel segments. Throughout the procedure, analysis of cell morphology and endothelial markers allowed us to select an endothelial fraction which after two rounds of expansion yielded a population of >90% pure endothelial cells. These cells have the features and functionalities of freshly isolated cells and can be used for biochemical studies. The technique was successfully used for aortic vessel segments of 20 patients and 3 healthy donors.

CONCLUSIONS/SIGNIFICANCE

This simple and highly reproducible method allows the simultaneous preparation of reasonably pure primary cultures of intimal and adventitial human endothelial cells, thus providing a reliable source for investigating their biology and involvement in both thoracic aneurysms and other aortic diseases.

An update on the etiology of abdominal aortic aneurysms: implications for future diagnostic testing

Abdominal aortic aneurysm (AAA) disease is multifactorial with both environmental and genetic risk factors. The current research in AAA revolves around genetic profiles and expression studies in both human and animal models. Variants in genes involved in extracellular matrix degradation, inflammation, the renin-angiotensin system, cell growth and proliferation and lipid metabolism have been associated with AAA using a variety of study designs. However, the results have been inconsistent and without a standard animal model for validation. Thus, despite the growing body of knowledge, the specific variants responsible for AAA development, progression and rupture have yet to be determined. This review explores some of the more significant genetic studies to provide an overview of past studies that have influenced the current understanding of AAA etiology. Expanding our understanding of disease pathogenesis will inform research into novel diagnostics and therapeutics and ultimately to improve outcomes for patients with AAA.

Hypoperfusion of the Adventitial Vasa Vasorum Develops an Abdominal Aortic Aneurysm

The aortic wall is perfused by the adventitial vasa vasorum (VV). Tissue hypoxia has previously been observed as a manifestation of enlarged abdominal aortic aneurysms (AAAs). We sought to determine whether hypoperfusion of the adventitial VV could develop AAAs. We created a novel animal model of adventitial VV hypoperfusion with a combination of a polyurethane catheter insertion and a suture ligation of the infrarenal abdominal aorta in rats. VV hypoperfusion caused tissue hypoxia and developed infrarenal AAA, which had similar morphological and pathological characteristics to human AAA. In human AAA tissue, the adventitial VV were stenotic in both small AAAs (30-49 mm in diameter) and in large AAAs (> 50 mm in diameter), with the sac tissue in these AAAs being ischemic and hypoxic. These results indicate that hypoperfusion of adventitial VV has critical effects on the development of infrarenal AAA.

The pathophysiologic basis of abdominal aortic aneurysm progression: a critical appraisal

An aneurysm of the abdominal aorta is a common pathology and a major cause of sudden death in the elderly. Currently, abdominal aortic aneurysms (AAAs) can only be treated by surgery and an effective medical therapy is urgently missing. The pathophysiology of AAAs is complex and is believed to be best described as a comprehensive inflammatory response with an accompanying proteolytic imbalance; the latter being held responsible for the progressive weakening of the aortic wall. Remarkably, while interference in inflammatory and/or proteolytic cascades proves highly effective in preclinical studies, emerging clinical studies consistently fail to show a benefit. In fact, some anti-inflammatory interventions appear to adversely influence the disease process. Altogether, recent clinical observations not only challenge the prevailing concepts of AAA progression, but also raise doubt on the translatability of findings from rodent models for growing AAA.

The Abdominal Aortic Aneurysm and Intraluminal Thrombus: Current Concepts of Development and Treatment

The pathogenesis of the abdominal aortic aneurysm (AAA) shows several hallmarks of atherosclerotic and atherothrombotic disease, but comprises an additional, predominant feature of proteolysis resulting in the degradation and destabilization of the aortic wall. This review aims to summarize the current knowledge on AAA development, involving the accumulation of neutrophils in the intraluminal thrombus and their central role in creating an oxidative and proteolytic environment. Particular focus is placed on the controversial role of heme oxygenase 1/carbon monoxide and nitric oxide synthase/peroxynitrite, which may exert both protective and damaging effects in the development of the aneurysm. Treatment indications as well as surgical and pharmacological options for AAA therapy are discussed in light of recent reports.

The role of the retromer complex in aging-related neurodegeneration: a molecular and genomic review

The retromer coat complex is a vital component of the intracellular trafficking mechanism sorting cargo from the endosomes to the trans-Golgi network or to the cell surface. In recent years, genes encoding components of the retromer coat complex and members of the vacuolar protein sorting 10 (Vps10) family of receptors, which play pleiotropic functions in protein trafficking and intracellular/intercellular signaling in neuronal and non-neuronal cells and are primary cargos of the retromer complex, have been implicated as genetic risk factors for sporadic and autosomal dominant forms of several neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and frontotemporal lobar degeneration. In addition to their functions in protein trafficking, the members of the Vps10 receptor family (sortilin, SorL1, SorCS1, SorCS2, and SorCS3) modulate neurotrophic signaling pathways. Both sortilin and SorCS2 act as cell surface receptors to mediate acute responses to proneurotrophins. In addition, sortilin can modulate the intracellular response to brain-derived neurotrophic factor (BDNF) by direct control of BDNF levels and regulating anterograde trafficking of Trk receptors to the synapse. This review article summarizes the emerging data from this rapidly growing field of intracellular trafficking signaling in the pathogenesis of neurodegeneration.

Vein graft aneurysms following popliteal aneurysm repair are more common than we think

True infrainguinal vein graft aneurysms are reported infrequently in the literature. We sought to identify the true incidence of these graft aneurysms after popliteal aneurysm repair and identify factors which may increase the risk of such aneurysms developing. Using a prospectively compiled database, we identified patients who underwent a popliteal aneurysm repair between January 1996 and January 2011 at a single district general hospital. Patients were routinely followed up in a graft surveillance programme. Out of 45 patients requiring repair of a popliteal aneurysm over a 15-year period, four (8.8%) patients developed aneurysmal graft disease. Of the patients who developed graft aneurysms, all had aneurysmal disease at other sites compared with 18 (45.0%) patients who did not develop graft aneurysms. Patients with graft aneurysms had a mean of 1.60 aneurysms elsewhere compared to 0.58 in patients with non-aneurysmal grafts ( P = 0.005). True vein graft aneurysms occur in a significant number of patients following popliteal aneurysm repair. Our data would suggest this to be more likely in patients who have aneurysms elsewhere and therefore a predisposition to aneurysmal disease. It may be appropriate for patients with aneurysms at other sites to undergo more prolonged post-operative graft surveillance.