Assessment of internet-based information on statin therapy

AIMS

The use of statin therapy is deemed to be controversial by mainstream media. Patients increasingly source medical information from the internet, and the use of statins is no exception. This study aims to determine the quality and educational content of statin-focused information on the internet and YouTube.

METHODS AND RESULTS

'Statin' was searched on Google, Yahoo!, Bing, and YouTube. The first 50 results obtained from each search engine and the first 20 YouTube videos were screened by two assessors. Websites were assessed using the Flesch Reading Ease (FRE) score, University of Michigan Consumer Health Website Evaluation Checklist, and a customized scoring system evaluating statin-focused content for quality. Videos were scored using the Journal of the American Medical Association (JAMA) benchmark criteria, Global Quality Score (GQS), and the customized scoring system. Websites scored a median FRE score of 57.5 [interquartile range (IQR) 52.1-62.3], median Michigan score of 36 (IQR 32-41.5), and median content score of 5 (IQR 3.75-7). Good interobserver agreement was demonstrated [Michigan score interobserver coefficient correlation (ICC) = 0.968; content score ICC = 0.944]. Videos scored a median JAMA score of 2, median GQS score of 2.5, and median content score of 2.5. Good interobserver agreement was demonstrated (JAMA ICC = 0.746; GQS ICC = 0.874; content score ICC = 0.946).

CONCLUSION

Quality and readability of statin-focused online information are poor. Healthcare professionals should be aware of the limitations of the current available sources and design online resources that are accurate and patient-friendly.

Reducing Abdominal Aortic Aneurysm Progression by Blocking Neutrophil Extracellular Traps Depends on Thrombus Formation

Neutrophil extracellular traps (NETs) are implicated in the pathogenesis of abdominal aortic aneurysm (AAA), located in adventitia and intraluminal thrombus. We compared the therapeutic potential of targeting upstream or downstream effector molecules of NET formation in 2 murine AAA models based on angiotensin II or peri-adventitial elastase application. In both models, NETs were detected in formed aneurysms at treatment start. Although NET inhibitors failed in the elastase model, they prevented progression of angiotensin II-induced aneurysms with thrombus, which resembles established human disease (including thrombus development). Blockade of upstream NET mediators was more effective than interference with downstream NET molecules.

Side-by-side comparison of published small molecule inhibitors against thapsigargin-induced store-operated Ca2+ entry in HEK293 cells

Calcium (Ca2+) is a key second messenger in eukaryotes, with store-operated Ca2+ entry (SOCE) being the main source of Ca2+ influx into non-excitable cells. ORAI1 is a highly Ca2+-selective plasma membrane channel that encodes SOCE. It is ubiquitously expressed in mammals and has been implicated in numerous diseases, including cardiovascular disease and cancer. A number of small molecules have been identified as inhibitors of SOCE with a variety of potential therapeutic uses proposed and validated in vitro and in vivo. These encompass both nonselective Ca2+ channel inhibitors and targeted selective inhibitors of SOCE. Inhibition of SOCE can be quantified both directly and indirectly with a variety of assay setups, making an accurate comparison of the activity of different SOCE inhibitors challenging. We have used a fluorescence based Ca2+ addback assay in native HEK293 cells to generate dose-response data for many published SOCE inhibitors. We were able to directly compare potency. Most compounds were validated with only minor and expected variations in potency, but some were not. This could be due to differences in assay setup relating to the mechanism of action of the inhibitors and highlights the value of a singular approach to compare these compounds, as well as the general need for biorthogonal validation of novel bioactive compounds. The compounds observed to be the most potent against SOCE in our study were: 7-azaindole 14d (12), JPIII (17), Synta-66 (6), Pyr 3 (5), GSK5503A (8), CM4620 (14) and RO2959 (7). These represent the most promising candidates for future development of SOCE inhibitors for therapeutic use.

VENUM (Vascular Education iN Undergraduate Medicine): a multicentre evaluation of undergraduate vascular education in the UK

INTRODUCTION

Vascular surgery is a recognised surgical subspecialty covering an array of circulatory conditions predominately affecting geriatric and diabetic patients. As such, a wide breadth of clinicians will see patients with vascular pathologies, but it is unclear how detailed their knowledge base is. Key to this is the education of medical students, which has been poorly documented during undergraduate training in the UK. VENUM aimed to establish students' perceptions of vascular surgery and their confidence in performing vascular objective structured clinical examination (OCSE) skills.

METHODS

During the academic year of 2022/2023, final-year medical students were invited to complete a JISC survey (collaborative authorship). Seventy-seven research leads were recruited to disseminate the survey. Quantitative and thematic analysis was used to assess the data.

RESULTS

In total, 240 final-year medical students completed the survey (54% female; 26 medical schools represented). Forty-five per cent of students reported never having had a vascular placement, 24% had never completed a vascular-focused clinical examination and 26% reported low confidence in performing ankle brachial pressure index measurement. An assessment of peripheral arterial disease morbidity was answered correctly in 17% of respondents compared with 92% for angina (chi-square test p<0.001). Students perceived the specialty to be non-inclusive and that early exposure to vascular surgery was required for better engagement with the specialty.

CONCLUSION

Students have experienced little exposure to vascular surgery. This may affect future recruitment to vascular surgery and overall knowledge of vascular conditions in UK-trained doctors, which may affect long-term patient management.

Assessment of Available Online Website and YouTube Resources for Patients with Abdominal Aortic Aneurysms

BACKGROUND

Over the last decade, patients have displayed a greater tendency to search for online information related to their health before seeking advice from a clinician. This study aims to determine the current quality and educational content of online patient information for abdominal aortic aneurysms (AAAs).

METHODS

In March 2022, the 3 most popular search engines by market shares (Google, Yahoo!, and Bing) and the video platform YouTube were interrogated for the term "abdominal aortic aneurysm". Validated scoring tools were used to assess quality and readability of the top 50 results for each search engine and to evaluate reliability and educational quality of the first 20 YouTube videos returned by the search. A custom-made scoring system was used to assess content.

RESULTS

Forty-five unique websites were analysed, 29% of which held Health on the Net certification. Median Flesch-Kincaid Reading Ease (interquartile range [IQR]) was 56.4 (50.4-62.75), with the average website falling under the "difficult to read" category. Median Michigan score (IQR) was 38.5 (32-43.5), reflecting "weak" quality. Websites with a higher content-specific score had a significantly higher median Michigan score. Sixty percent of websites discussed benefits and risks related to AAA treatment, and only 31% discussed advantages and disadvantages of open versus endovascular treatment. No websites mentioned the volume-outcome relationship in aneurysm surgery. Eight unique YouTube videos were assessed. Median Journal of the American Medical Association score (IQR) was 2 (2-2.25). Median Global Quality Score score (IQR) was 3 (2-4). Median content score was 1 (0-2).

CONCLUSIONS

The current average online information on AAA is of 'weak' quality and 'difficult' (i.e., above the standard reading ability of a 13- to 15-year-old) readability. Healthcare providers should focus on the provision of better AAA-focused patient information (e.g., appropriately referenced, regularly reviewed, and limiting advertisements where possible). The involvement of patient advisory groups during resource development is highly recommended.

Relationship Among Diabetes, Obesity, and Cardiovascular Disease Phenotypes: A UK Biobank Cohort Study

OBJECTIVE

Obesity and diabetes frequently coexist, yet their individual contributions to cardiovascular risk remain debated. We explored cardiovascular disease biomarkers, events, and mortality in the UK Biobank stratified by BMI and diabetes.

RESEARCH DESIGN AND METHODS

A total of 451,355 participants were stratified by ethnicity-specific BMI categories (normal, overweight, obese) and diabetes status. We examined cardiovascular biomarkers including carotid intima-media thickness (CIMT), arterial stiffness, left ventricular ejection fraction (LVEF), and cardiac contractility index (CCI). Poisson regression models estimated adjusted incidence rate ratios (IRRs) for myocardial infarction, ischemic stroke, and cardiovascular death, with normal-weight nondiabetes as comparator.

RESULTS

Five percent of participants had diabetes (10% normal weight, 34% overweight, and 55% obese vs. 34%, 43%, and 23%, respectively, without diabetes). In the nondiabetes group, overweight/obesity was associated with higher CIMT, arterial stiffness, and CCI and lower LVEF (P < 0.005); these relationships were diminished in the diabetes group. Within BMI classes, diabetes was associated with adverse cardiovascular biomarker phenotype (P < 0.005), particularly in the normal-weight group. After 5,323,190 person-years follow-up, incident myocardial infarction, ischemic stroke, and cardiovascular mortality rose across increasing BMI categories without diabetes (P < 0.005); this was comparable in the diabetes groups (P-interaction > 0.05). Normal-weight diabetes had comparable adjusted cardiovascular mortality to obese nondiabetes (IRR 1.22 [95% CI 0.96-1.56]; P = 0.1).

CONCLUSIONS

Obesity and diabetes are additively associated with adverse cardiovascular biomarkers and mortality risk. While adiposity metrics are more strongly correlated with cardiovascular biomarkers than diabetes-oriented metrics, both correlate weakly, suggesting that other factors underpin the high cardiovascular risk of normal-weight diabetes.

Evaluation of national institute for health and care excellence guidance for ruptured abdominal aortic aneurysms by emulating a hypothetical target trial

Objective

This retrospective study evaluates the performance of UK National Institute for Health and Care Excellence (NICE) Guidelines on management of ruptured abdominal aortic aneurysms in a "real world setting" by emulating a hypothetical target trial with data from two European Aortic Centers.

Methods

Clinical data was retrospectively collected for all patients who had undergone ruptured endovascular aneurysm repair (rEVAR) and ruptured open surgical repair (rOSR). Survival analysis was performed comparing NICE compliance to usual care strategy. NICE compliers were defined as: female patients undergoing rEVAR; male patients >70 years old undergoing rEVAR; and male patients ≤70 years old undergoing rOSR. Hemodynamic instability was considered additionally.

Results

This multicenter study included 298 patients treated for rAAA. The majority of patients were treated with rOSR (186 rOSR vs. 112 rEVAR). Overall, 184 deaths (68 [37%] with rEVAR and 116 [63%] with rOSR) were observed during the study period. Overall survival under usual care was 69.2% at 30 days, 56.5% at one year, and 42.4% at 5 years. NICE compliance gave survival outcomes of 73.1% at 30 days, 60.2% at 1 year and 42.9% at 5 years. The risk ratios at these time points, comparing NICE-compliance to usual care, were 0.88, 0.92 and 0.99, respectively.

Conclusions

We support NICE recommendations to manage men below the age of 71 years and hemodynamic stability with rOSR. There was a slight survival advantage for NICE compliers overall, in men >70 years and women of all ages.

Analyzing Sex Differences in Intensity of Cardiovascular Disease Prevention Medications in Patients With Abdominal Aortic Aneurysms-A Single-Center Cross-Sectional Study

BACKGROUND

Patients with abdominal aortic aneurysm (AAA) are at a significant risk of cardiovascular events, similar to that of patients who have already experienced a major cardiac event. The European Society for Vascular Society AAA guidelines suggest that antiplatelet therapy and lipid-lowering therapy (LLT) should be considered in all patients with AAA. This study explores the overall prevalence and intensity of antithrombotic therapy and LLT, and lipid profile monitoring in a single center AAA surveillance cohort alongside any sex differences.

METHODS

This was a retrospective, single center, cross-sectional study of 614 patients enrolled in the AAA surveillance program of a tertiary vascular surgery unit. All patients undergoing at least 1 surveillance scan from January 1, 2018, to December 31, 2020, were assessed. Electronic hospital records linked to real-time primary care records were interrogated for data on demographics, comorbidities, antiplatelet and LLT prescriptions, and serum cholesterol laboratory results. An analysis of covariance test was used to account for the effects of confounding comorbidities.

RESULTS

Twenty-one percent of patients were not on antithrombotic therapy, and 20% of patients were not on LLT which reflects a group of patients receiving sub-optimal clinical care. In total, 47% of the cohort were on low/moderate intensity statin therapy which reflects a group of patients where care can be improved upon. Female sex was independently associated with a reduced likelihood of being prescribed LLT (P = 0.008, eta squared (η_p²) = 0.012, small effect size) but not antithrombotic therapy (P = 0.202). Fewer women underwent low-density lipoprotein cholesterol (LDL-C) monitoring (mean difference 9%, P = 0.040) and achieved the European Society of Cardiology-European Atherosclerosis Society- LDL-C target of <1.4 mmol/L (mean difference 9%, P = 0.040).

CONCLUSIONS

Overall, there is room for improvement in these aspects of cardiovascular risk prevention for both sexes. Sex differences in the prescription of LLT, the prevalence of lipid profile monitoring, and likelihood of achieving LDL-C targets exist among patients with AAA, with a lower prevalence in women.

An Automated Method for Artifical Intelligence Assisted Diagnosis of Active Aortitis Using Radiomic Analysis of FDG PET-CT Images

The aim of this study was to develop and validate an automated pipeline that could assist the diagnosis of active aortitis using radiomic imaging biomarkers derived from [18F]-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography (FDG PET-CT) images. The aorta was automatically segmented by convolutional neural network (CNN) on FDG PET-CT of aortitis and control patients. The FDG PET-CT dataset was split into training (43 aortitis:21 control), test (12 aortitis:5 control) and validation (24 aortitis:14 control) cohorts. Radiomic features (RF), including SUV metrics, were extracted from the segmented data and harmonized. Three radiomic fingerprints were constructed: A-RFs with high diagnostic utility removing highly correlated RFs; B used principal component analysis (PCA); C-Random Forest intrinsic feature selection. The diagnostic utility was evaluated with accuracy and area under the receiver operating characteristic curve (AUC). Several RFs and Fingerprints had high AUC values (AUC > 0.8), confirmed by balanced accuracy, across training, test and external validation datasets. Good diagnostic performance achieved across several multi-centre datasets suggests that a radiomic pipeline can be generalizable. These findings could be used to build an automated clinical decision tool to facilitate objective and standardized assessment regardless of observer experience.

Orai1 Inhibitors as Potential Treatments for Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterized by progressive distal pulmonary artery (PA) obstruction, leading to right ventricular hypertrophy and failure. Exacerbated intracellular calcium (Ca²⁺) signaling contributes to abnormalities in PA smooth muscle cells (PASMCs), including aberrant proliferation, apoptosis resistance, exacerbated migration, and arterial contractility. Store-operated Ca²⁺ entry is involved in Ca²⁺ homeostasis in PASMCs, but its properties in PAH are unclear.

METHODS

Using a combination of Ca²⁺ imaging, molecular biology, in vitro, ex vivo, and in vivo approaches, we investigated the roles of the Orai1 SOC channel in PA remodeling in PAH and determined the consequences of pharmacological Orai1 inhibition in vivo using experimental models of pulmonary hypertension (PH).

RESULTS

Store-operated Ca²⁺ entry and Orai1 mRNA and protein were increased in human PASMCs (hPASMCs) from patients with PAH (PAH-hPASMCs). We found that MEK1/2 (mitogen-activated protein kinase kinase 1/2), NFAT (nuclear factor of activated T cells), and NFκB (nuclear factor-kappa B) contribute to the upregulation of Orai1 expression in PAH-hPASMCs. Using small interfering RNA (siRNA) and Orai1 inhibitors, we found that Orai1 inhibition reduced store-operated Ca²⁺ entry, mitochondrial Ca²⁺ uptake, aberrant proliferation, apoptosis resistance, migration, and excessive calcineurin activity in PAH-hPASMCs. Orai1 inhibitors reduced agonist-evoked constriction in human PAs. In experimental rat models of PH evoked by chronic hypoxia, monocrotaline, or Sugen/hypoxia, administration of Orai1 inhibitors (N-{4-[3,5-bis(Trifluoromethyl)-1H-pyrazol-1-yl]phenyl}-4-methyl-1,2,3-thiadiazole-5-carboxamide [BTP2], 4-(2,5-dimethoxyphenyl)-N-[(pyridin-4-yl)methyl]aniline [JPIII], or 5J4) protected against PH.

CONCLUSIONS

In human PAH and experimental PH, Orai1 expression and activity are increased. Orai1 inhibition normalizes the PAH-hPASMCs phenotype and attenuates PH in rat models. These results suggest that Orai1 should be considered as a relevant therapeutic target for PAH.

Exploratory Analysis of Serial 18F-fluciclovine PET-CT and Multiparametric MRI during Chemoradiation for Glioblastoma

Anti-1-amino-3-18fluorine-fluorocyclobutane-1-carboxylic acid (18F-fluciclovine) positron emission tomography (PET) shows preferential glioma uptake but there is little data on how uptake correlates with post-contrast T1-weighted (Gd-T1) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) activity during adjuvant treatment. This pilot study aimed to compare 18F-fluciclovine PET, DCE-MRI and Gd-T1 in patients undergoing chemoradiotherapy for glioblastoma (GBM), and in a parallel pre-clinical GBM model, to investigate correlation between 18F-fluciclovine uptake, MRI findings, and tumour biology. 18F-fluciclovine-PET-computed tomography (PET-CT) and MRI including DCE-MRI were acquired before, during and after adjuvant chemoradiotherapy (60 Gy in 30 fractions with temozolomide) in GBM patients. MRI volumes were manually contoured; PET volumes were defined using semi-automatic thresholding. The similarity of the PET and DCE-MRI volumes outside the Gd-T1 volume boundary was measured using the Dice similarity coefficient (DSC). CT-2A tumour-bearing mice underwent MRI and 18F-fluciclovine PET-CT. Post-mortem mice brains underwent immunohistochemistry staining for ASCT2 (amino acid transporter), nestin (stemness) and Ki-67 (proliferation) to assess for biologically active tumour. 6 patients were recruited (GBM 1-6) and grouped according to overall survival (OS)-short survival (GBM-SS, median OS 249 days) and long survival (GBM-LS, median 903 days). For GBM-SS, PET tumour volumes were greater than DCE-MRI, in turn greater than Gd-T1. For GBM-LS, Gd-T1 and DCE-MRI were greater than PET. Tumour-specific 18F-fluciclovine uptake on pre-clinical PET-CT corresponded to immunostaining for Ki-67, nestin and ASCT2. Results suggest volumes of 18F-fluciclovine-PET activity beyond that depicted by DCE-MRI and Gd-T1 are associated with poorer prognosis in patients undergoing chemoradiotherapy for GBM. The pre-clinical model confirmed 18F-fluciclovine uptake reflected biologically active tumour.

3D Ultrasound Measurements Are Highly Sensitive to Monitor Formation and Progression of Abdominal Aortic Aneurysms in Mouse Models

Background

Available mouse models for abdominal aortic aneurysms (AAAs) differ substantially in the applied triggers, associated pathomechanisms and rate of vessel expansion. While maximum aortic diameter (determined after aneurysm excision or by 2D ultrasound) is commonly applied to document aneurysm development, we evaluated the sensitivity and reproducibility of 3D ultrasound to monitor aneurysm growth in four distinct mouse models of AAA.

Methods

The models included angiotensin-II infusion in ApoE deficient mice, topical elastase application on aortas in C57BL/6J mice (with or without oral administration of β-aminoproprionitrile) and intraluminal elastase perfusion in C57BL/6J mice. AAA development was monitored using semi-automated 3D ultrasound for aortic volume calculation over 12 mm length and assessment of maximum aortic diameter.

Results

While the models differed substantially in the time course of aneurysm development, 3D ultrasound measurements (volume and diameter) proved highly reproducible with concordance correlation coefficients > 0.93 and variations below 9% between two independent observers. Except for the elastase perfusion model where aorta expansion was lowest and best detected by diameter increase, all other models showed high sensitivity of absolute volume and diameter measurements in monitoring AAA formation and progression by 3D ultrasound. When compared to standard 2D ultrasound, the 3D derived parameters generally reached the highest effect size.

Conclusion

This study has yielded novel information on the robustness and limitations of semi-automated 3D ultrasound analysis and provided the first direct comparison of aortic volume increase over time in four widely applied mouse models of AAA. While 3D ultrasound generally proved highly sensitive in detecting early AAA formation, the 3D based volume analysis was found inferior to maximum diameter assessment in the elastase perfusion model where the extent of inflicted local injury is determined by individual anatomical features.

Absence of association between host genetic mutations in the ORAI1 gene and COVID-19 fatality

The calcium ion channel ORAI1 has emerged as a promising therapeutic target for the Coronavirus Disease 19 (COVID-19)-associated pneumonia, and a pharmacological inhibitor of ORAI1 has now reached clinical trials for severe COVID-19 pneumonia. Whether ORAI1 itself is associated with an increased risk for severe COVID-19 presentation is still unknown. Here, we employed genetic association analysis to investigate the potential association of host genetic polymorphisms of ORAI1 with the risk of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and its associated COVID-19 fatality in UK Biobank participants from white British background. The analysis showed no significant association between ORAI1 variants and COVID-19 positivity or fatality, despite the well-established roles of ORAI1 in immune response and inflammation and the success of ORAI1 inhibition in clinical trials. Our results suggest that the host genetic polymorphisms of ORAI1 are unlikely to be implicated in the broad variability in symptoms severity among afflicted patients.

High-Frequency Three-Dimensional Lumen Volume Ultrasound Is a Sensitive Method to Detect Early Aneurysmal Change in Elastase-Induced Murine Abdominal Aortic Aneurysm

Objective  The aim of this study was to investigate the reproducibility of anterior–posterior diameter (APd _max ) and three-dimensional lumen volume (3DLV) measurements of abdominal aortic aneurysms (AAA) in a classical murine AAA model. We also compared the magnitude of change in the aortic size detected with each method of assessment.

Methods  Periadventitial application of porcine pancreatic elastase (PPE AAA) or sham surgery was performed in two cohorts of mice. Cohort 1 was used to assess for observer variability with the APd _max and 3DLV measurements. Cohort 2 highlighted the relationship between APd _max and 3DLV and changes in AAA detected.

Results  There was no significant observer variability detected with APd _max measurement. Similarly, no significant intraobserver variability was evident with 3DLV; however, a small but significant interobserver difference was present. APd _max and 3DLV measurements of PPE AAA significantly correlated. However, changes in the AAA morphology were detected earlier with 3DLV.

Conclusion  APd _max and 3DLV are both reliable methods for measuring an AAA. Both these methods correlate with each other. However, changes in AAA morphology were detected earlier with 3DLV, which is important to detect subtle but important changes to aortic geometry in a laboratory setting. 3DLV measurement of AAA is a simple, reproducible, and comprehensive method for assessing changes in disease morphology.

Cell proliferation detected using [18F]FLT PET/CT as an early marker of abdominal aortic aneurysm

BACKGROUND

Abdominal aortic aneurysm (AAA) is a focal aortic dilatation progressing towards rupture. Non-invasive AAA-associated cell proliferation biomarkers are not yet established. We investigated the feasibility of the cell proliferation radiotracer, fluorine-18-fluorothymidine ([18F]FLT) with positron emission tomography/computed tomography (PET/CT) in a progressive pre-clinical AAA model (angiotensin II, AngII infusion).

METHODS AND RESULTS

Fourteen-week-old apolipoprotein E-knockout (ApoE-/-) mice received saline or AngII via osmotic mini-pumps for 14 (n = 7 and 5, respectively) or 28 (n = 3 and 4, respectively) days and underwent 90-minute dynamic [18F]FLT PET/CT. Organs were harvested from independent cohorts for gamma counting, ultrasound scanning, and western blotting. [18F]FLT uptake was significantly greater in 14- (n = 5) and 28-day (n = 3) AAA than in saline control aortae (n = 5) (P < 0.001), which reduced between days 14 and 28. Whole-organ gamma counting confirmed greater [18F]FLT uptake in 14-day AAA (n = 9) compared to saline-infused aortae (n = 4) (P < 0.05), correlating positively with aortic volume (r = 0.71, P < 0.01). Fourteen-day AAA tissue showed increased expression of thymidine kinase-1, equilibrative nucleoside transporter (ENT)-1, ENT-2, concentrative nucleoside transporter (CNT)-1, and CNT-3 than 28-day AAA and saline control tissues (n = 3 each) (all P < 0.001).

CONCLUSIONS

[18F]FLT uptake is increased during the active growth phase of the AAA model compared to saline control mice and late-stage AAA.

[18F]Fluorothymidine Uptake in the Porcine Pancreatic Elastase-Induced Model of Abdominal Aortic Aneurysm

The porcine pancreatic elastase (PPE) model is a common preclinical model of abdominal aortic aneurysms (AAA). Some notable characteristics of this model include the low aortic rupture rate, non-progressive disease course, and infra-renal AAA formation. Enhanced [18F]fluorothymidine ([18F]FLT) uptake on positron emission tomography/computed tomography (PET/CT) has previously been reported in the angiotensin II-induced murine model of AAA. Here, we report our preliminary findings of investigating [18F]FLT uptake in the PPE murine model of AAA. [18F]FLT uptake was found to be substantially increased in the abdominal areas recovering from the surgery, whilst it was not found to be significantly increased within the PPE-induced AAA, as confirmed using in vivo PET/CT and ex vivo whole-organ gamma counting (PPE, n = 7; controls, n = 3). This finding suggests that the [18F]FLT may not be an appropriate radiotracer for this specific AAA model, and further studies with larger sample sizes are warranted to elucidate the pathobiology contributing to the reduced uptake of [18F]FLT in this model.

Elimination of fibrin γ-chain cross-linking by FXIIIa increases pulmonary embolism arising from murine inferior vena cava thrombi

The onset of venous thromboembolism, including pulmonary embolism, represents a significant health burden affecting more than 1 million people annually worldwide. Current treatment options are based on anticoagulation, which is suboptimal for preventing further embolic events. In order to develop better treatments for thromboembolism, we sought to understand the structural and mechanical properties of blood clots and how this influences embolism in vivo. We developed a murine model in which fibrin γ-chain cross-linking by activated Factor XIII is eliminated (FGG3X) and applied methods to study thromboembolism at whole-body and organ levels. We show that FGG3X mice have a normal phenotype, with overall coagulation parameters and platelet aggregation and function largely unaffected, except for total inhibition of fibrin γ-chain cross-linking. Elimination of fibrin γ-chain cross-linking resulted in thrombi with reduced strength that were prone to fragmentation. Analysis of embolism in vivo using Xtreme optical imaging and light sheet microscopy demonstrated that the elimination of fibrin γ-chain cross-linking resulted in increased embolization without affecting clot size or lysis. Our findings point to a central previously unrecognized role for fibrin γ-chain cross-linking in clot stability. They also indirectly indicate mechanistic targets for the prevention of thrombosis through selective modulation of fibrin α-chain but not γ-chain cross-linking by activated Factor XIII to reduce thrombus size and burden, while maintaining clot stability and preventing embolism.

Histone citrullination as a novel biomarker and target to inhibit progression of abdominal aortic aneurysms

Neutrophil extracellular traps (NETs) have been implicated in the pathogenesis of abdominal aortic aneurysms (AAAs). This study has addressed the notion that NET components might serve as AAA biomarkers or novel targets of AAA therapy. Thus, parameters of neutrophil activation and NET formation were measured in plasma. Their diagnostic marker value was explored in 41 AAA patients and 38 healthy controls. The NET parameter citrullinated histone H3 (citH3) was then validated in 63 AAA patients and 63 controls matched for cardiovascular disease. The prognostic marker potential was investigated in 54 observation periods of AAA growth over 6 months. NETs were further assessed in conditioned medium and sections of aortic tissue. CitH3 was found to be increased in blood (median 362 vs 304 ng/mL, P = 0.004) and aortic tissue (50 vs 1.5 ng/mg, P < 0.001) of AAA patients compared to healthy controls and accumulated in the intraluminal thrombus (629 ng/mg). The diagnostic potential of citH3 ranged at 0.705 area under the ROC curve (AUROC) and was validated with the independent sample set. Furthermore, plasma citH3 predicted AAA growth over the next 6 months (AUROC: 0.707, P = 0.015) and dropped significantly after surgical aneurysm repair. In an angiotensin II - based mouse model of experimental AAA, an inhibitor of histone citrullination was applied to block NET formation and AAA progression. Of note, further growth of an established aneurysm was prevented in mice treated with the NET inhibitor (P = 0.040). In conclusion, histone citrullination represents a promising AAA biomarker and potential therapeutic target to control disease progression.

Role of MicroRNA-145 in DNA Damage Signalling and Senescence in Vascular Smooth Muscle Cells of Type 2 Diabetic Patients

Increased cardiovascular morbidity and mortality in individuals with type 2 diabetes (T2DM) is a significant clinical problem. Despite advancements in achieving good glycaemic control, this patient population remains susceptible to macrovascular complications. We previously discovered that vascular smooth muscle cells (SMC) cultured from T2DM patients exhibit persistent phenotypic aberrancies distinct from those of individuals without a diagnosis of T2DM. Notably, persistently elevated expression levels of microRNA-145 co-exist with characteristics consistent with aging, DNA damage and senescence. We hypothesised that increased expression of microRNA-145 plays a functional role in DNA damage signalling and subsequent cellular senescence specifically in SMC cultured from the vasculature of T2DM patients. In this study, markers of DNA damage and senescence were unambiguously and permanently elevated in native T2DM versus non-diabetic (ND)-SMC. Exposure of ND cells to the DNA-damaging agent etoposide inflicted a senescent phenotype, increased expression of apical kinases of the DNA damage pathway and elevated expression levels of microRNA-145. Overexpression of microRNA-145 in ND-SMC revealed evidence of functional links between them; notably increased secretion of senescence-associated cytokines and chronic activation of stress-activated intracellular signalling pathways, particularly the mitogen-activated protein kinase, p38α. Exposure to conditioned media from microRNA-145 overexpressing cells resulted in chronic p38α signalling in naïve cells, evidencing a paracrine induction and reinforcement of cell senescence. We conclude that targeting of microRNA-145 may provide a route to novel interventions to eliminate DNA-damaged and senescent cells in the vasculature and to this end further detailed studies are warranted.

ORAI1 Ca2+ Channel as a Therapeutic Target in Pathological Vascular Remodelling

In the adult, vascular smooth muscle cells (VSMC) are normally physiologically quiescent, arranged circumferentially in one or more layers within blood vessel walls. Remodelling of native VSMC to a proliferative state for vascular development, adaptation or repair is driven by platelet-derived growth factor (PDGF). A key effector downstream of PDGF receptors is store-operated calcium entry (SOCE) mediated through the plasma membrane calcium ion channel, ORAI1, which is activated by the endoplasmic reticulum (ER) calcium store sensor, stromal interaction molecule-1 (STIM1). This SOCE was shown to play fundamental roles in the pathological remodelling of VSMC. Exciting transgenic lineage-tracing studies have revealed that the contribution of the phenotypically-modulated VSMC in atherosclerotic plaque formation is more significant than previously appreciated, and growing evidence supports the relevance of ORAI1 signalling in this pathologic remodelling. ORAI1 has also emerged as an attractive potential therapeutic target as it is accessible to extracellular compound inhibition. This is further supported by the progression of several ORAI1 inhibitors into clinical trials. Here we discuss the current knowledge of ORAI1-mediated signalling in pathologic vascular remodelling, particularly in the settings of atherosclerotic cardiovascular diseases (CVDs) and neointimal hyperplasia, and the recent developments in our understanding of the mechanisms by which ORAI1 coordinates VSMC phenotypic remodelling, through the activation of key transcription factor, nuclear factor of activated T-cell (NFAT). In addition, we discuss advances in therapeutic strategies aimed at the ORAI1 target.

Imaging Biological Pathways in Abdominal Aortic Aneurysms Using Positron Emission Tomography

[Figure: see text].

The abdominal waist circumference and 4-year outcomes following peripheral bypass grafting

BACKGROUND

Current literature evaluating the relationship between obesity, utilizing measures other than the Body Mass Index (BMI), and postoperative outcomes following vascular surgery are sparse. This study aimed to investigate any association between abdominal waist circumference (AWC) and waist-hip ratio (WHR) in relation to postoperative morbidity and mortality following peripheral artery bypass graft (PABG) surgery.

METHODS

AWC and hip circumference (HC) were measured from pre-intervention magnetic resonance (MR) and computed tomography (CT) scans of patients undergoing elective and nonelective PABG. The AWC and WHR were assessed in relation to: the need for higher level care (i.e. level 2/3), the duration of higher level care, postoperative limb ischemia, postoperative hospital stay, graft patency on discharge and 30 day readmission, using logistic and linear regression analysis. Mortality was assessed using cox-regression analysis with calculation of hazard ratios at 30 days and 4 years.

RESULTS

In total, 177 patient images performed between January 2014 to January 2017 were analyzed. There were no significant intra-observer and interobserver differences in measurements of AWC and HC. Pre-intervention AWC was predictive of the need for higher level care following non-elective PABG (adjusted OR 1.1 [95% CI: 1.0-1.1, P=0.026]). An inverse relationship between AWC and mortality at 4 years was also observed (adjusted HR=0.9, 95% CI: 0.9-1.0, P=0.028). However, pre-intervention WHR failed to predict mortality and morbidity.

CONCLUSIONS

AWC may potentially be a suitable risk stratification tool in patients undergoing non-elective PABG. The association of AWC with long-term mortality outcomes require further investigation so that suitable cut-off values may be determined.

A pilot multicentre randomised controlled trial of lidocaine infusion in women undergoing breast cancer surgery

Chronic postoperative pain is common after breast cancer surgery. Peri-operative lidocaine infusion may prevent the development of chronic postoperative pain, but a large-scale trial is required to test this hypothesis. It is unclear whether a pragmatic, multicentre trial design that is consistent with expert guidance, addresses the limitations of previous studies, and overcomes existing translational barriers is safe, effective and feasible. We conducted a double-blind, randomised controlled pilot study in 150 patients undergoing breast cancer surgery across three hospitals in Western Australia. Patients received lidocaine, or equivalent volumes of saline, as an intravenous bolus (1.5 mg.kg^-1 ) and infusion (2 mg.kg^-1 .h^-1 ) intra-operatively, and a subcutaneous infusion (1.33 mg.kg^-1 .h^-1 ) postoperatively for up to 12 h on a standard surgical ward, with novel safety monitoring tools in place. The co-primary outcomes were: in-hospital safety events; serum levels of lidocaine during intravenous and subcutaneous infusion; and annualised enrolment rates per site with long-term data capture. In-hospital safety events were rare, and similar in the placebo and lidocaine arms (3% vs. 1%). Median (IQR [range]) serum lidocaine levels during intravenous (2.16 (1.74-2.83 [1.12-6.06]) µg.ml^-1 , n = 41) and subcutaneous (1.52 (1.28-1.83 [0.64-2.85]) µg.ml^-1 , n = 48) infusion were comparable with previous trials reporting improved pain outcomes. Annualised enrolment approximated 50 patients per site per year, with high levels of protocol adherence and ≥ 99% capture of outcomes at 3 and 6 months. The adjusted odds ratio (95%CI) for postoperative pain at 6 months in the lidocaine arm was 0.790 (0.370-1.684). We conclude that this trial, as designed, is safe, effective and feasible in patients undergoing breast cancer surgery, and a larger-scale trial is planned.

Interleukin-6 Receptor Signaling and Abdominal Aortic Aneurysm Growth Rates

Supplemental Digital Content is available in the text.

Background:

The Asp358Ala variant (rs2228145; A>C) in the IL (interleukin)-6 receptor (IL6R) gene has been implicated in the development of abdominal aortic aneurysms (AAAs), but its effect on AAA growth over time is not known. We aimed to investigate the clinical association between the IL6R-Asp358Ala variant and AAA growth and to assess the effect of blocking the IL-6 signaling pathway in mouse models of aortic aneurysm rupture or dissection.

Methods:

Using data from 2863 participants with AAA from 9 prospective cohorts, age- and sex-adjusted mixed-effects linear regression models were used to estimate the association between the IL6R-Asp358Ala variant and annual change in AAA diameter (mm/y). In a series of complementary randomized trials in mice, the effect of blocking the IL-6 signaling pathways was assessed on plasma biomarkers, systolic blood pressure, aneurysm diameter, and time to aortic rupture and death.

Results:

After adjusting for age and sex, baseline aneurysm size was 0.55 mm (95% CI, 0.13–0.98 mm) smaller per copy of the minor allele [C] of the Asp358Ala variant. Change in AAA growth was −0.06 mm per year (−0.18 to 0.06) per copy of the minor allele; a result that was not statistically significant. Although all available worldwide data were used, the genetic analyses were not powered for an effect size as small as that observed. In 2 mouse models of AAA, selective blockage of the IL-6 trans-signaling pathway, but not combined blockage of both, the classical and trans-signaling pathways, was associated with improved survival (P<0.05).

Conclusions:

Our proof-of-principle data are compatible with the concept that IL-6 trans-signaling is relevant to AAA growth, encouraging larger-scale evaluation of this hypothesis.

The role of cardiopulmonary exercise testing and echocardiography prior to elective endovascular aneurysm repair

INTRODUCTION

Cardiopulmonary exercise testing (CPET) and transthoracic echocardiography (TTE) are common preparative investigations prior to elective endovascular aneurysm repair (EVAR). Whether these investigations can predict survival following EVAR and contribute to shared decision making is unknown.

METHODS

Patients who underwent EVAR at a tertiary centre between June 2007 and December 2014 were identified from the National Vascular Registry. Variables obtained from preoperative investigations were assessed for their association with survival at three years. Regression analysis was used to determine variables that independently predicted survival at three years.

RESULTS

A total of 199 patients underwent EVAR during the study period. Of these, 120 had preoperative CPET and 123 had TTE. Lower forced expiratory ventilation (FEV₁), ratio of FEV₁ to forced vital capacity, work at peak oxygen consumption and higher ventilatory equivalent for carbon dioxide were associated with increased mortality. Variables obtained from TTE were not associated with survival at three years although there was a low incidence of left ventricular systolic dysfunction and significant valvular disease in this cohort.

CONCLUSIONS

CPET might be a useful adjunct to assist in shared decision making in patients undergoing elective EVAR and may influence anaesthetic technique. TTE does not appear to be able to discriminate between high and low risk individuals. However, a low rate of significant ventricular dysfunction and valvular disease in patients undergoing elective EVAR may account for these findings.

Orai1 Channel Inhibition Preserves Left Ventricular Systolic Function and Normal Ca2+ Handling After Pressure Overload

BACKGROUND

Orai1 is a critical ion channel subunit, best recognized as a mediator of store-operated Ca²⁺ entry (SOCE) in nonexcitable cells. SOCE has recently emerged as a key contributor of cardiac hypertrophy and heart failure but the relevance of Orai1 is still unclear.

METHODS

To test the role of these Orai1 channels in the cardiac pathophysiology, a transgenic mouse was generated with cardiomyocyte-specific expression of an ion pore-disruptive Orai1^R91W mutant (C-dnO1). Synthetic chemistry and channel screening strategies were used to develop 4-(2,5-dimethoxyphenyl)-N-[(pyridin-4-yl)methyl]aniline (hereafter referred to as JPIII), a small-molecule Orai1 channel inhibitor suitable for in vivo delivery.

RESULTS

Adult mice subjected to transverse aortic constriction (TAC) developed cardiac hypertrophy and reduced ventricular function associated with increased Orai1 expression and Orai1-dependent SOCE (assessed by Mn²⁺ influx). C-dnO1 mice displayed normal cardiac electromechanical function and cellular excitation-contraction coupling despite reduced Orai1-dependent SOCE. Five weeks after TAC, C-dnO1 mice were protected from systolic dysfunction (assessed by preserved left ventricular fractional shortening and ejection fraction) even if increased cardiac mass and prohypertrophic markers induction were observed. This is correlated with a protection from TAC-induced cellular Ca²⁺ signaling alterations (increased SOCE, decreased [Ca²⁺]_i transients amplitude and decay rate, lower SR Ca²⁺ load and depressed cellular contractility) and SERCA2a downregulation in ventricular cardiomyocytes from C-dnO1 mice, associated with blunted Pyk2 signaling. There was also less fibrosis in heart sections from C-dnO1 mice after TAC. Moreover, 3 weeks treatment with JPIII following 5 weeks of TAC confirmed the translational relevance of an Orai1 inhibition strategy during hypertrophic insult.

CONCLUSIONS

The findings suggest a key role of cardiac Orai1 channels and the potential for Orai1 channel inhibitors as inotropic therapies for maintaining contractility reserve after hypertrophic stress.

Symptom relief in patients undergoing endovascular management of chronic mesenteric ischemia

BACKGROUND

Chronic mesenteric ischemia (CMI) is a rare, but potentially fatal condition, which is becoming increasingly prevalent in elderly patients. This study investigated the impact of endovascular intervention on patient symptomology and the influence of extent of mesenteric disease on patient morbidity and mortality.

METHODS

All patients who underwent primary angioplasty (±stenting) to the mesenteric vessels for CMI between July 2008 to July 2017 were retrospectively identified. Patient data relating to comorbidities, clinical presentation, disease burden, procedural details, symptomatology, reintervention and mortality were collected. Mortality was assessed using regression analysis, which was adjusted for age and gender.

RESULTS

Overall, 38 patients were included in the study. The median age was 73.5 years (interquartile range, 70.0-77.8). Abdominal pain (N.=36), postprandial pain (N.=32) and weight loss (N.=32) were the most common symptoms reported at presentation. Technical success was achieved in 37 patients. Thirty-two patients were symptom free at 6 weeks and 29 patients were symptom free at 2 years. Overall 5 patients required reintervention. At 30 days and 2 years one and seven patients were deceased, respectively. Significant association was observed between three vessel intervention and overall mortality (adjusted odds ratio 14.5, 95% confidence interval: 1.28-165.86, P=0.031). Majority of patients died of a cause unrelated to their CMI.

CONCLUSIONS

Endovascular intervention for CMI is safe and provides satisfactory short-term and intermediate term symptom resolution in majority of patients. This study supports the routine use of endovascular intervention in the management of this complex disease.

Meta-analysis of fenestrated endovascular aneurysm repair versus open surgical repair of juxtarenal abdominal aortic aneurysms over the last 10 years

Background

Juxtarenal abdominal aortic aneurysms pose a significant challenge whether managed endovascularly or by open surgery. Fenestrated endovascular aneurysm repair (FEVAR) is now well established, but few studies have compared it with open surgical repair (OSR). The aim of this systematic review was to compare short‐ and long‐term outcomes of FEVAR and OSR for the management of juxtarenal aortic aneurysms.

Methods

A literature search was conducted of the Ovid Medline, EMBASE and PubMed databases. Reasons for exclusion were series with fewer than 20 patients, studies published before 2007 and those concerning ruptured aneurysms. Owing to variance in definitions, the terms ‘juxta/para/suprarenal’ were used; thoracoabdominal aortic aneurysms were excluded. Primary outcomes were 30‐day/in‐hospital mortality and renal insufficiency. Secondary outcomes included major complication rates, rate of reintervention and rates of endoleak.

Results

Twenty‐seven studies were identified, involving 2974 patients. Study designs included 11 case series, 14 series within retrospective cohort studies, one case–control study and a single prospective non‐randomized trial. The pooled early postoperative mortality rate following FEVAR was 3·3 (95 per cent c.i. 2·0 to 5·0) per cent, compared with 4·2 (2·9 to 5·7) per cent after OSR. After FEVAR, the rate of postoperative renal insufficiency was 16·2 (10·4 to 23·0) per cent, compared with 23·8 (15·2 to 33·6) per cent after OSR. The major early complication rate following FEVAR was 23·1 (16·8 to 30·1) per cent versus 43·5 (34·4 to 52·8) per cent after OSR. The rate of late reintervention after FEVAR was higher than that after OSR: 11·1 (6·7 to 16·4) versus 2·0 (0·6 to 4·3) per cent respectively.

Conclusion

No significant difference was noted in 30‐day mortality; however, FEVAR was associated with significantly lower morbidity than OSR. Long‐term durability is a concern, with far higher reintervention rates after FEVAR.

Volumetric versus single slice measurements of core abdominal muscle for sarcopenia

OBJECTIVE

We investigated whether total psoas muscle area (TPMA) was representative of the total psoas muscle volume (TPMV). Secondly, we assessed whether there was a relationship between the two commonly used single slice measurements of sarcopenia, TPMA and total abdominal muscle area (TAMA).

METHODS

Pre-operative CT imaging of 110 patients undergoing elective endovascular aneurysm repair were analyzed by two trained independent observers. TPMA was measured at individual vertebral levels between the second lumbar vertebrae and sacrum. TPMV was also estimated between the second lumbar vertebrae and sacrum. TAMA was measured at the third lumbar vertebrae (L3). Observer differences were assessed using Bland-Altman plots. Associations between the different measures were assessed using linear regression and Pearson's correlation.

RESULTS

We found single slice measurements of the TPMA to be representative of the TPMV at individual levels between L2 to the sacrum. The strongest association was seen at L3 [adjusted regression coefficient 16.7, 95% confidence interval (12.1 to 21.4), p < 0.001]. There was no association between TPMA and TAMA [adjusted regression coefficient -0.7, 95% confidence interval (-4.1 to 2.8), p = 0.710].

CONCLUSION

We demonstrate that measurements of the TPMA between L2 to the sacrum are representative of the TPMV, with the greatest association at the third lumbar vertebrae. There was no association between the TPMA and TAMA.

ADVANCES IN KNOWLEDGE

We demonstrate that a single slice measurement of TPMA at L3 is representative of the muscle volume, contrary to previous criticism. Future sarcopenia studies can continue to measure TPMA which is representative of the TPMV.

Influence of psoas muscle area on mortality following elective abdominal aortic aneurysm repair

BACKGROUND

The effect of sarcopenia based on the total psoas muscle area (TPMA) on CT is inconclusive in patients undergoing abdominal aortic aneurysm (AAA) intervention. The aim of this prospective cohort study was to evaluate morphometric sarcopenia as a method of risk stratification in patients undergoing elective AAA intervention.

METHODS

TPMA was measured on preintervention CT images of patients undergoing elective endovascular aneurysm repair (EVAR) or open aneurysm repair. Mortality was assessed in relation to preintervention TPMA using Cox regression analysis, with calculation of hazard ratios at 30 days, 1 year and 4 years. Postintervention morbidity was evaluated in terms of postintervention care, duration of hospital stay and 30-day readmission. Changes in TPMA on surveillance EVAR imaging were also evaluated.

RESULTS

In total, 382 patient images acquired between March 2008 and December 2016 were analysed. There were no significant intraobserver and interobserver differences in measurements of TPMA. Preintervention TPMA failed to predict morbidity and mortality at all time points. The mean(s.d.) interval between preintervention and surveillance imaging was 361·3(111·2) days. A significant reduction in TPMA was observed in men on surveillance imaging after EVAR (mean reduction 0·63(1·43) cm2 per m2 ; P < 0·001). However, this was not associated with mortality (adjusted hazard ratio 1·00, 95 per cent c.i. 0·99 to 1·01; P = 0·935).

CONCLUSION

TPMA is not a suitable risk stratification tool for patients undergoing effective intervention for AAA.

A Novel Diagnostic and Prognostic Score for Abdominal Aortic Aneurysms Based on D-Dimer and a Comprehensive Analysis of Myeloid Cell Parameters

The pathogenesis of abdominal aortic aneurysm (AAA) involves a central component of chronic inflammation which is predominantly mediated by myeloid cells. We hypothesized that the local inflammatory activity may be reflected in systemic alterations of neutrophil and monocyte populations as well as in soluble factors of myeloid cell activation and recruitment. To establish their marker potential, neutrophil and monocyte sub-sets were measured by flow cytometry in peripheral blood samples of 41 AAA patients and 38 healthy controls matched for age, sex, body mass index and smoking habit. Comparably, circulating factors reflecting neutrophil and monocyte activation and recruitment were assayed in plasma. Significantly elevated levels of CD16+ monocytes, activated neutrophils and newly released neutrophils were recorded for AAA patients compared with controls. In line, the monocyte chemoattractant C-C chemokine ligand 2 and myeloperoxidase were significantly increased in patients' plasma. The diagnostic value was highest for myeloperoxidase, a mediator which is released by activated neutrophils as well as CD16+ monocytes. Multivariable regression models using myeloid activation markers and routine laboratory parameters identified myeloperoxidase and D-dimer as strong independent correlates of AAA. These two biomarkers were combined to yield a diagnostic score which was subsequently challenged for confounders and confirmed in a validation cohort matched for cardiovascular disease. Importantly, the score was also found suited to predict rapid disease progression. In conclusion, D-dimer and myeloperoxidase represent two sensitive biomarkers of AAA which reflect distinct hallmarks (thrombus formation and inflammation) of the pathomechanism and, when combined, may serve as diagnostic and prognostic AAA score warranting further evaluation.

ORAI Channels as Potential Therapeutic Targets in Pulmonary Hypertension

Pulmonary hypertension is a complex and fatal disease that lacks treatments. Its pathophysiology involves pulmonary artery hyperreactivity, endothelial dysfunction, wall remodelling, inflammation, and thrombosis, which could all depend on ORAI Ca²⁺ channels. We review the knowledge about ORAI channels in pulmonary artery and discuss the interest to target them in the treatment of pulmonary hypertension.

Modelling the growth of popliteal artery aneurysms

Background

Popliteal artery aneurysms (PAAs) comprise up to 85 per cent of all peripheral aneurysms. Few longitudinal studies track their progression. This study aimed to track the growth of asymptomatic PAAs in a hospital-based ultrasound service, and compare models of aneurysm growth.

Methods

This retrospective single-centre cohort study included patients who had a PAA on arterial duplex ultrasound imaging of the lower limbs between 1 January 2011 and 1 January 2016. Progression of PAA size and progression to event or intervention were the primary outcome measures.

Results

Some 282 images were analysed: 47 limbs with PAA were included in a cohort of 32 patients (15 had bilateral PAAs). Twenty patients also had an abdominal aortic aneurysm (AAA). Linear multilevel modelling estimated that PAA growth was 2·4 (95 per cent c.i. 1·6 to 3·7) mm a year. Growth was estimated at 0·8 (0·1 to 1·5) mm per year in patients without an AAA and 3·5 (2·9 to 4·2) mm per year in those with a known AAA (previous open repair, previous endovascular aneurysm repair or AAA under surveillance) (P &lt; 0·001).

Conclusion

Growth rates of PAA were heterogeneous but were optimally predicted by multilevel modelling. Patients with an existing AAA may have faster PAA progression than those without.

Progressive Development of Aberrant Smooth Muscle Cell Phenotype in Abdominal Aortic Aneurysm Disease

Abdominal aortic aneurysm (AAA) is a silent, progressive disease with a high mortality and an increasing prevalence with aging. Smooth muscle cell (SMC) dysfunction contributes to gradual dilatation and eventual rupture of the aorta. Here we studied phenotypic characteristics in SMC cultured from end-stage human AAA (≥5 cm) and cells cultured from a porcine carotid artery (PCA) model of early and end-stage aneurysm. Human AAA-SMC presented a secretory phenotype and expressed elevated levels of the differentiation marker miR-145 (2.2-fold, p < 0.001) and the senescence marker SIRT-1 (1.3-fold, p < 0.05), features not recapitulated in aneurysmal PCA-SMC. Human and end-stage porcine aneurysmal cells were frequently multi-nucleated (3.9-fold, p < 0.001, and 1.8-fold, p < 0.01, respectively, vs. control cells) and displayed an aberrant nuclear morphology. Human AAA-SMC exhibited higher levels of the DNA damage marker γH2AX (3.9-fold, p < 0.01, vs. control SMC). These features did not correlate with patients' chronological age and are therefore potential markers for pathological premature vascular aging. Early-stage PCA-SMC (control and aneurysmal) were indistinguishable from one another across all parameters. The principal limitation of human studies is tissue availability only at the end stage of the disease. Refinement of a porcine bioreactor model would facilitate the study of temporal modulation of SMC behaviour during aneurysm development and potentially identify therapeutic targets to limit AAA progression.

Piezo1 channels sense whole body physical activity to reset cardiovascular homeostasis and enhance performance

Mammalian biology adapts to physical activity but the molecular mechanisms sensing the activity remain enigmatic. Recent studies have revealed how Piezo1 protein senses mechanical force to enable vascular development. Here, we address Piezo1 in adult endothelium, the major control site in physical activity. Mice without endothelial Piezo1 lack obvious phenotype but close inspection reveals a specific effect on endothelium-dependent relaxation in mesenteric resistance artery. Strikingly, the Piezo1 is required for elevated blood pressure during whole body physical activity but not blood pressure during inactivity. Piezo1 is responsible for flow-sensitive non-inactivating non-selective cationic channels which depolarize the membrane potential. As fluid flow increases, depolarization increases to activate voltage-gated Ca²⁺ channels in the adjacent vascular smooth muscle cells, causing vasoconstriction. Physical performance is compromised in mice which lack endothelial Piezo1 and there is weight loss after sustained activity. The data suggest that Piezo1 channels sense physical activity to advantageously reset vascular control.The mechanisms that regulate the body's response to exercise are poorly understood. Here, Rode et al. show that the mechanically activated cation channel Piezo1 is a molecular sensor of physical exercise in the endothelium that triggers endothelial communication to mesenteric vessel muscle cells, leading to vasoconstriction.

Picomolar, selective, and subtype-specific small-molecule inhibition of TRPC1/4/5 channels

The concentration of free cytosolic Ca²⁺ and the voltage across the plasma membrane are major determinants of cell function. Ca²⁺-permeable non-selective cationic channels are known to regulate these parameters, but understanding of these channels remains inadequate. Here we focus on transient receptor potential canonical 4 and 5 proteins (TRPC4 and TRPC5), which assemble as homomers or heteromerize with TRPC1 to form Ca²⁺-permeable non-selective cationic channels in many mammalian cell types. Multiple roles have been suggested, including in epilepsy, innate fear, pain, and cardiac remodeling, but limitations in tools to probe these channels have restricted progress. A key question is whether we can overcome these limitations and develop tools that are high-quality, reliable, easy to use, and readily accessible for all investigators. Here, through chemical synthesis and studies of native and overexpressed channels by Ca²⁺ and patch-clamp assays, we describe compound 31, a remarkable small-molecule inhibitor of TRPC1/4/5 channels. Its potency ranged from 9 to 1300 pm, depending on the TRPC1/4/5 subtype and activation mechanism. Other channel types investigated were unaffected, including TRPC3, TRPC6, TRPV1, TRPV4, TRPA1, TRPM2, TRPM8, and store-operated Ca²⁺ entry mediated by Orai1. These findings suggest identification of an important experimental tool compound, which has much higher potency for inhibiting TRPC1/4/5 channels than previously reported agents, impressive specificity, and graded subtype selectivity within the TRPC1/4/5 channel family. The compound should greatly facilitate future studies of these ion channels. We suggest naming this TRPC1/4/5-inhibitory compound Pico145.

Meta-Analysis of Genome-Wide Association Studies for Abdominal Aortic Aneurysm Identifies Four New Disease-Specific Risk Loci

Supplemental Digital Content is available in the text.

Rationale:

Abdominal aortic aneurysm (AAA) is a complex disease with both genetic and environmental risk factors. Together, 6 previously identified risk loci only explain a small proportion of the heritability of AAA.

Objective:

To identify additional AAA risk loci using data from all available genome-wide association studies.

Methods and Results:

Through a meta-analysis of 6 genome-wide association study data sets and a validation study totaling 10 204 cases and 107 766 controls, we identified 4 new AAA risk loci: 1q32.3 (SMYD2), 13q12.11 (LINC00540), 20q13.12 (near PCIF1/MMP9/ZNF335), and 21q22.2 (ERG). In various database searches, we observed no new associations between the lead AAA single nucleotide polymorphisms and coronary artery disease, blood pressure, lipids, or diabetes mellitus. Network analyses identified ERG, IL6R, and LDLR as modifiers of MMP9, with a direct interaction between ERG and MMP9.

Conclusions:

The 4 new risk loci for AAA seem to be specific for AAA compared with other cardiovascular diseases and related traits suggesting that traditional cardiovascular risk factor management may only have limited value in preventing the progression of aneurysmal disease.

Renal extracellular vesicles: from physiology to clinical application

Urinary extracellular vesicles (uEVs) are released from all regions of the kidney's nephron and from other cells that line the urinary tract. Extracellular vesicles retain proteomic and transcriptomic markers specific to their cell of origin and so represent a potential reservoir for kidney disease biomarker discovery. Exosomes, a subtype of uEVs, are distinguished from other vesicles by features related to their biogenesis within cells: mature multi-vesicular bodies fuse with the cellular membrane to liberate exosomes into the extracellular space. uEVs represent a novel cell signalling mechanism because they can be shuttled to a recipient cell and, through a number of proposed mechanisms, affect the recipient cell's proteome and function. Here we review the current evidence for uEV signalling along the nephron, their role in health and disease of the kidney, and their potential for clinical translation as biomarkers and therapeutics.

Small bowel obstruction in pregnancy is a complex surgical problem with a high risk of fetal loss

INTRODUCTION

Small bowel obstruction (SBO) in pregnancy is rare and is most commonly caused by adhesions from previous abdominal surgery. Previous literature reviews have emphasised the need for prompt laparotomy in all cases of SBO because of the significant risks of fetal loss and maternal mortality. We undertook a review of the contemporary literature to determine the optimum management strategy for SBO in pregnancy.

METHODS

The MEDLINE® and PubMed databases were searched for cases of SBO in pregnancy between 1992 and 2014. Two cases from our own institution were also reviewed.

RESULTS

Forty-six cases of SBO in pregnancy were identified, with adhesions being the most common aetiology (50%). The overall risk of fetal loss was 17% and the maternal mortality rate was 2%. In cases of adhesional SBO, 91% of cases were managed surgically, with 14% fetal loss. Two cases (9%) were managed conservatively with no complications. Magnetic resonance imaging (MRI) was used to diagnose SBO in 11% of cases.

CONCLUSIONS

Based on our experience and the contemporary literature, we recommend that urgent MRI of the abdomen should be undertaken to diagnose the aetiology of SBO in pregnancy. In cases of adhesional SBO, conservative treatment may be safely commenced, with a low threshold for laparotomy. In other causes, such as volvulus or internal hernia, laparotomy remains the treatment of choice.

Low Prevalence of netB and tpeL in Historical Clostridium perfringens Isolates from Broiler Farms in Alabama

The discovery of novel Clostridium perfringens toxins NetB and TpeL has initiated questions regarding their role in the pathogenesis of disease. However, data showing the prevalence of these genes in C. perfringens populations are limited to certain geographical areas. If netB and tpeL are important virulence factors for disease worldwide, one would expect to find these genes in isolates from other regions as well. To address this hypothesis, C. perfringens isolates collected from Alabama broiler farms over 15 yr ago were toxin genotyped using PCR. Each isolate was screened for netB and tpeL; the major lethal toxin genes cpa, cpb, etx, and ia; and the enterotoxin gene cpe. Results of the assay showed all isolates presumed to be C. perfringens were genotypically type A, cpe negative except for one broiler litter isolate, which was genotypically type C. Only two isolates were positive for netB. Similarly, only two isolates were positive for tpeL, one of which was also netB positive. The low incidence observed for netB and tpeL indicates that these genes are not significant virulence factors for the sampled population.

Orai3 Surface Accumulation and Calcium Entry Evoked by Vascular Endothelial Growth Factor

Supplemental Digital Content is available in the text.

Vascular endothelial growth factor (VEGF) acts, in part, by triggering calcium ion (Ca²⁺) entry. Here, we sought understanding of a Synta66-resistant Ca²⁺ entry pathway activated by VEGF.

Restoring Akt1 activity in outgrowth endothelial cells from South Asian men rescues vascular reparative potential

Recent data suggest reduced indices of vascular repair in South Asian men, a group at increased risk of cardiovascular events. Outgrowth endothelial cells (OEC) represent an attractive tool to study vascular repair in humans and may offer potential in cell-based repair therapies. We aimed to define and manipulate potential mechanisms of impaired vascular repair in South Asian (SA) men. In vitro and in vivo assays of vascular repair and angiogenesis were performed using OEC derived from SA men and matched European controls, prior defining potentially causal molecular mechanisms. SA OEC exhibited impaired colony formation, migration, and in vitro angiogenesis, associated with decreased expression of the proangiogenic molecules Akt1 and endothelial nitric oxide synthase (eNOS). Transfusion of European OEC into immunodeficient mice after wire-induced femoral artery injury augmented re-endothelialization, in contrast with SA OEC and vehicle; SA OEC also failed to promote angiogenesis after induction of hind limb ischemia. Expression of constitutively active Akt1 (E17KAkt), but not green fluorescent protein control, in SA OEC increased in vitro angiogenesis, which was abrogated by a NOS antagonist. Moreover, E17KAkt expressing SA OEC promoted re-endothelialization of wire-injured femoral arteries, and perfusion recovery of ischemic limbs, to a magnitude comparable with nonmanipulated European OEC. Silencing Akt1 in European OEC recapitulated the functional deficits noted in SA OEC. Reduced signaling via the Akt/eNOS axis is causally linked with impaired OEC-mediated vascular repair in South Asian men. These data prove the principle of rescuing marked reparative dysfunction in OEC derived from these men.

Aspirin therapy is associated with less compact fibrin networks and enhanced fibrinolysis in patients with abdominal aortic aneurysm

OBJECTIVE

Thrombotic changes in fibrin networks contribute to increased cardiovascular risk in patients with abdominal aortic aneurysm (AAA). Given that aspirin modulates the fibrin network, we aimed to determine if aspirin therapy is associated with changes in ex-vivo fibrin clot characteristics in AAA patients and also conducted an exploratory analysis of 5-year mortality in these individuals.

METHODS

We recruited 145 male patients, divided into controls (aortic diameter < 3 cm, n = 49), AAA not taking aspirin (AAA-Asp, n = 50) and AAA on 75 mg day(-1) aspirin (AAA+Asp, n = 46), matched for aneurysm size. Characteristics of clots made from plasma and plasma-purified fibrinogen were investigated using turbidimetric analysis, permeation studies, and confocal and electron microscopy. Plasma fibrinogen, D-dimer and inflammatory marker levels were also measured.

RESULTS

Maximum absorbance (MA) of plasma clots from controls was lower than that of AAA patients not on aspirin (AAA-Asp) at 0.30 ± 0.01 and 0.38 ± 0.02 au, respectively (P = 0.002), whereas aspirin-treated subjects had MA similar to controls (0.31 ± 0.02 P = 0.9). Plasma clot lysis time displayed an identical pattern at 482 ± 15, 597 ± 24 and 517 ± 27 s for control, AAA-Asp and AAA+Asp (P = 0.001 and P = 0.8). The lysis time of clots made from purified fibrinogen of AAA-Asp was longer than that of AAA+Asp patients (756 ± 47 and 592 ± 52 s, respectively; P = 0.041). Permeation studies and confocal and electron microscopy showed increased clot density in AAA-Asp compared with the AAA+Asp group. Mortality in AAA-Asp and AAA+Asp was similar, despite increased cardiovascular risk in the latter group, and both exhibited higher mortality than controls.

CONCLUSION

Aspirin improves fibrin clot characteristics in patients with AAA, which may have important clinical implications.