Increased serum angiopoietin-2 is associated with abdominal aortic aneurysm prevalence and cardiovascular mortality in older men

Current Prognostic Biomarkers for Abdominal Aortic Aneurysm: A Comprehensive Scoping Review of the Literature

Abdominal aortic aneurysm (AAA) is a progressive dilatation of the aorta that can lead to aortic rupture. The pathophysiology of the disease is not well characterized but is known to be caused by the general breakdown of the extracellular matrix within the aortic wall. In this comprehensive literature review, all current research on proteins that have been investigated for their potential prognostic capabilities in patients with AAA was included. A total of 45 proteins were found to be potential prognostic biomarkers for AAA, predicting incidence of AAA, AAA rupture, AAA growth, endoleak, and post-surgical mortality. The 45 proteins fell into the following seven general categories based on their primary function: (1) cardiovascular health, (2) hemostasis, (3) transport proteins, (4) inflammation and immunity, (5) kidney function, (6) cellular structure, (7) and hormones and growth factors. This is the most up-to-date literature review on current prognostic markers for AAA and their functions. This review outlines the wide pathophysiological processes that are implicated in AAA disease progression.

Identification and Evaluation of Blood-Based Biomarkers for Abdominal Aortic Aneurysm

INTRODUCTION

Blood-based biomarkers for abdominal aortic aneurysm (AAA) have been studied individually; however, we considered a panel of proteins to investigate AAA prognosis and its potential to improve predictive accuracy.

MATERIALS AND METHODS

Using a prospectively recruited cohort of patients with/without AAA (n = 452), we conducted a prognostic study to develop a model that accurately predicts AAA outcomes using clinical features and circulating biomarker levels. Serum concentrations of 9 biomarkers were measured at baseline, and the cohort was followed for 2 years. The primary outcome was major adverse aortic event (MAAE; composite of rapid AAA expansion [>0.5 cm/6 months or >1 cm/12 months], AAA intervention, or AAA rupture). Using 10-fold cross-validation, we trained a random forest model to predict 2 year MAAE using (1) clinical characteristics, (2) biomarkers, and (3) clinical characteristics and biomarkers.

RESULTS

Two-year MAAE occurred in 114 (25%) patients. Two proteins were significantly elevated in patients with AAA compared with those without AAA (angiopoietin-2 and aggrecan), composing the protein panel. For predicting 2 year MAAE, our random forest model achieved area under the receiver operating characteristic curve (AUROC) 0.74 using clinical features alone, and the addition of the 2-protein panel improved performance to AUROC 0.86.

CONCLUSIONS

Using a combination of clinical/biomarker data, we developed a model that accurately predicts 2 year MAAE.

Global research status analysis of the association between aortic aneurysm and inflammation: a bibliometric analysis from 1999 to 2023

Background

Aortic aneurysm is a chronic arterial disease that can lead to aortic rupture, causing severe complications and life-threatening risks for patients, and it is one of the common causes of death among the elderly. Increasing evidence suggests that inflammation plays an important role in the progression of aortic aneurysm. However, there is a lack of literature-based quantitative analysis in this field.

Methods

Up to March 30, 2023, we collected 3,993 articles related to aortic aneurysm and inflammation from the Web of Science Core Collection (WoSCC) database for bibliometric analysis. The collected literature data were subjected to visual analysis of regional distribution, institutions, authors, keywords, and other information using tools such as CiteSpace, VOSviewer, the R package "bibliometric," and online platforms.

Results

The number of publications in this research field has been steadily increasing each year, with the United States and China being the main contributing countries. Harvard University in the United States emerged as the most active and influential research institution in this field. Jonathan Golledge and Peter Libby were identified as the authors with the highest publication output and academic impact, respectively. Researchers in this field tend to publish their findings in influential journals such as the Journal of Vascular Surgery and Arteriosclerosis Thrombosis and Vascular Biology. "Abdominal aortic aneurysm," "giant cell arteritis," "arterial stiffness," and "smooth muscle cells" were identified as the hottest topics in the field of aortic aneurysm and inflammation. In terms of keyword co-occurrence analysis, "Clinical relevant studies of AA" (red), "Inflammatory activation" (green), "Inflammatory mechanisms related to pathogenesis" (dark blue), "Cytokines" (yellow), "Risk factors" (purple), and "Pathological changes in vascular wall" (cyan) formed the major research framework in this field. "Inflammation-related pathogenesis" and "inflammation activation" have emerged as recent hot research directions, with "monocytes," "progression," and "proliferation" being the prominent topics.

Conclusion

This study provides a comprehensive analysis of the knowledge network framework and research hotspots in the field of aortic aneurysm and inflammation through a literature-based quantitative approach. It offers valuable insights to guide scholars in identifying meaningful research directions in this field.

Plasma angiopoietin-2 and its association with heart failure in patients with atrial fibrillation

AIMS

Several biomarkers are associated with clinical outcomes in patients with atrial fibrillation (AF), but a causal relationship has not been established. This study aimed to evaluate angiopoietin-2, a novel candidate biomarker of endothelial inflammation and vascular remodelling, in patients with AF.

METHODS AND RESULTS

Angiopoietin-2 was measured in plasma obtained from patients with AF treated with aspirin monotherapy (exploration cohort, n = 2987) or with oral anticoagulation (validation cohort, n = 13 079). Regression models were built to assess the associations between angiopoietin-2, clinical characteristics, and outcomes. In both cohorts, plasma angiopoietin-2 was independently associated with AF on the baseline electrocardiogram and persistent/permanent AF, age, history of heart failure, female sex, tobacco use/smoking, body mass index, renal dysfunction, diabetes, and N-terminal pro-B-type natriuretic peptide (NT-proBNP). Angiopoietin-2 was independently associated with subsequent hospitalization for heart failure after adjusting for age, creatinine, and clinical characteristics in the exploration cohort [c-index 0.79, 95% confidence interval (CI) 0.75-0.82; third vs. first quartile, hazard ratio (HR) 1.74, 95% CI 1.26-2.41] and in the validation cohort (c-index 0.76, 95% CI 0.74-0.78; HR 1.58, 95% CI 1.37-1.82). In both cohorts, the association persisted when also adjusting for NT-proBNP (P ≤ 0.001). In full multivariable models also adjusted for NT-proBNP, angiopoietin-2 did not show statistically significant associations with ischaemic stroke, cardiovascular and all-cause death, or major bleeding that were consistent across the two cohorts.

CONCLUSIONS

In patients with AF, plasma levels of angiopoietin-2 were independently associated with subsequent hospitalization for heart failure and provided incremental prognostic value to clinical risk factors and NT-proBNP.

DNA methylation alternation in Stanford- A acute aortic dissection

Background

Acute aortic dissection (AAD) is a life-threatening cardiovascular disease. Recent studies have shown that DNA methylation may be associated with the pathological mechanism of AAD, but the panorama of DNA methylation needs to be explored.

Methods

DNA methylation patterns were screened using Infinium Human Methylation 450 K BeadChip in the aortic tissues from 4 patients with Stanford-A AAD and 4 controls. Gene enrichment was analyzed by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and gene ontology (GO). DNA methylation levels of candidate genes were determined by pyrosequencing in the replication cohort including 16 patients with AAD and 7 controls. Protein expression level of candidate gene was assessed by Western blot.

Results

A total of 589 differentially methylated positions including 315 hypomethylated and 274 hypermethylated positions were found in AAD group. KEGG analysis demonstrated that differentially methylated position-associated genes were enriched in MAPK signaling pathway, TNF signaling pathway and apoptosis pathway, et al. GO analysis demonstrated that differentially methylated position-associated genes were enriched in protein binding, angiogenesis and heart development et al. The differential DNA methylation in five key genes, including Fas, ANGPT2, DUSP6, FARP1 and CARD6, was authenticated in the independent replication cohort. The protein expression level of the Fas was increased by 1.78 times, indicating the possible role of DNA methylation in regulation of gene expression.

Conclusion

DNA methylation was markedly changed in the aortic tissues of Stanford-A AAD and associated with gene dysregulation, involved in AAD progression.

Supplementary Information

The online version contains supplementary material available at10.1186/s12872-022-02882-5.

Angiopoietin-2 and angiopoietin-like 4 protein provide prognostic information in patients with suspected acute coronary syndrome

BACKGROUND

Plasma levels of angiopoietin-2 (ANGPT2) and angiopoietin-like 4 protein (ANGPTL4) reflect different pathophysiological aspects of cardiovascular disease. We evaluated their association with outcome in a hospitalized Norwegian patient cohort (n = 871) with suspected acute coronary syndrome (ACS) and validated our results in a similar Argentinean cohort (n = 982).

METHODS

A cox regression model, adjusting for traditional cardiovascular risk factors, was fitted for ANGPT2 and ANGPTL4, respectively, with all-cause mortality and cardiac death within 24 months and all-cause mortality within 60 months as the dependent variables.

RESULTS

At 24 months follow-up, 138 (15.8%) of the Norwegian and 119 (12.1%) of the Argentinian cohort had died, of which 86 and 66 deaths, respectively, were classified as cardiac. At 60 months, a total of 259 (29.7%) and 173 (17.6%) patients, respectively, had died. ANGPT2 was independently associated with all-cause mortality in both cohorts at 24 months [hazard ratio (HR) 1.27 (95% confidence interval (CI), 1.08-1.50) for Norway, and HR 1.57 (95% CI, 1.27-1.95) for Argentina], with similar results at 60 months [HR 1.19 (95% CI, 1.05-1.35) (Norway), and HR 1.56 (95% CI, 1.30-1.88) (Argentina)], and was also significantly associated with cardiac death [HR 1.51 (95% CI, 1.14-2.00)], in the Argentinean population. ANGPTL4 was significantly associated with all-cause mortality in the Argentinean cohort at 24 months [HR 1.39 (95% CI, 1.15-1.68)] and at 60 months [HR 1.43 (95% CI, 1.23-1.67)], enforcing trends in the Norwegian population.

CONCLUSIONS

ANGPT2 and ANGPTL4 were significantly associated with outcome in similar ACS patient cohorts recruited on two continents.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00521976. ClinicalTrials.gov Identifier: NCT01377402.

Associations of Angiopoietins With Heart Failure Incidence and Severity

BACKGROUND

Angiopoietin-1 and 2 (Ang1, Ang2) are important mediators of angiogenesis. Angiopoietin levels are perturbed in cardiovascular disease, but it is unclear whether angiopoietin signaling is causative, an adaptive response, or merely epiphenomenon of disease activity.

METHODS AND RESULTS

In a cohort free of cardiovascular disease at baseline (Multi-Ethnic Study of Atherosclerosis [MESA]), relationships between angiopoietins, cardiac morphology, and subsequent incidence of heart failure or cardiovascular death were evaluated. In cohorts with pulmonary arterial hypertension or left heart disease, associations between angiopoietins, invasive hemodynamics, and adverse clinical outcomes were evaluated. In MESA, Ang2 was associated with a higher incidence of heart failure or cardiovascular death (hazard ratio 1.21 per standard deviation, P < .001). Ang2 was associated with increased right atrial pressure (pulmonary arterial hypertension cohort) and increased wedge pressure and right atrial pressure (left heart disease cohort). Elevated Ang2 was associated with mortality in the pulmonary arterial hypertension cohort.

CONCLUSIONS

Ang2 was associated with incident heart failure or death among adults without cardiovascular disease at baseline and with disease severity in individuals with existing heart failure. Our finding that Ang2 is increased before disease onset and that elevations reflect disease severity, suggests Ang2 may contribute to heart failure pathogenesis.

Circulating growth factors and cardiac remodeling in the community: The Framingham Heart Study

BACKGROUND AND AIMS

Cardiac and vascular growth factors (GF) may influence myocardial remodeling through cardiac growth and angiogenic effects. We hypothesized that concentrations of circulating GF are associated with cardiac remodeling traits.

METHODS

We related blood concentrations of vascular endothelial GF (VEGF), VEGFR-1 (sFlt1), angiopoietin 2 (Ang-2), soluble angiopoietin type-2 receptor (sTie2), hepatocyte GF (HGF), insulin-like GF (IGF)-1, IGF binding protein (IGFBP)-3, and growth differentiation factor-15 (GDF-15) to echocardiographic traits in 3151 Framingham Study participants (mean age 40 years, 55% women). We evaluated the following measures: left ventricular (LV) mass index (LVMi), LV ejection fraction (LVEF), global longitudinal strain (GLS), mitral E/e', and aortic root diameter (AoR). All biomarker values were sex-standardized.

RESULTS

In multivariable-adjusted analyses, higher GDF-15 concentrations were associated with higher log-LVMi (β = 0.009 per SD, P = 0.01). Similarly, sTie2 concentrations were positively associated with log-E/e' (β = 0.011 per SD, P = 0.04). IGF-1 and Ang-2 concentrations were positively and negatively associated with GLS, respectively (βIGF-1 = 0.16 per SD and βAng-2 = -0.15 per SD, both P < 0.05), whereas higher sFlt1 and Ang-2 levels were associated with smaller log-AoR (βsFlt1 = -0.004 per SD and β Ang-2 = -0.005 per SD, respectively; P < 0.05).

CONCLUSION

In our large community-based sample, we observed patterns of associations between several circulating vascular GF and cardiac remodeling indices that are consistent with the known biological effects of these pro- and anti-angiogenic factors on the myocardium and conduit arteries. Additional studies are warranted to replicate our findings and assess their prognostic significance.

Decreased angiogenesis as a possible pathomechanism in cervical degenerative myelopathy

Endogenous immune mediated reactions of inflammation and angiogenesis are components of the spinal cord injury in patients with degenerative cervical myelopathy (DCM). The aim of this study was to identify alteration of certain mediators participating in angiogenetic and inflammatory reactions in patients with DCM. A consecutive series of 42 patients with DCM and indication for surgical decompression were enrolled for the study. 28 DCM patients were included, as CSF samples were taken preoperatively. We enrolled 42 patients requiring surgery for a thoracic abdominal aortic aneurysm (TAAA) as neurologically healthy controls. In 38 TAAA patients, CSF samples were taken prior to surgery and thus included. We evaluated the neurological status of patients and controls prior to surgery including NDI and mJOA. Protein-concentrations of factors with a crucial role in inflammation and angiogenesis were measured in CSF via ELISA testing (pg/ml): Angiopoietin 2, VEGF-A and C, RANTES, IL 1 beta and IL 8. Additionally, evaluated the status of the blood-spinal cord barrier (BSCB) by Reibers´diagnostic in all participants. Groups evidently differed in their neurological status (mJOA: DCM 10.1 ± 3.3, TAAA 17.3 ± 1.2, p < .001; NDI: DCM 47.4 ± 19.7, TAAA 5.3 ± 8.6, p < .001). There were no particular differences in age and gender distribution. However, we detected statistically significant differences in concentrations of mediators between the groups: Angiopoietin 2 (DCM 267.1.4 ± 81.9, TAAA 408.6 ± 177.1, p < .001) and VEGF C (DCM 152.2 ± 96.1, TAAA 222.4 ± 140.3, p = .04). DCM patients presented a mild to moderate BSCB disruption, controls had no signs of impairment. In patients with DCM, we measured decreased concentrations of angiogenic mediators. These results correspond to findings of immune mediated secondary harm in acute spinal cord injury. Reduced angiogenic activity could be a relevant part of the pathogenesis of DCM and secondary harm to the spinal cord.

Prognostic value of angiopoietin-2 for patients with coronary heart disease after elective PCI

Patients with coronary heart disease (CHD) frequently have cardiovascular complications after undergoing PCI. Angiopoietin-2 (Ang-2) is an important proangiogenic factor that also plays an important role in atherosclerosis. This study aimed to evaluate the value of Ang-2 in predicting cardiovascular events after elective PCI.This prospective study enrolled 97 patients with CHD who underwent elective PCI from 2013 to 2014. Blood samples were collected in the first morning after admission and within 24 to 48 h after PCI. The primary endpoint was cardiovascular events, defined as a composite of cardiac death, nonfatal myocardial infarction/repeat revascularization, readmission for severe deterioration of angina and readmission for new onset heart failure. Based on the median level of pre-PCI or post-PCI Ang-2, the patients were divided into a low level group and a high level group.During the whole follow-up period (mean, 53 ± 13 months), Kaplan-Meier curves of cardiovascular events showed that there was no significant difference between the two pre-PCI groups (χ = 2.22, P = .137, and log-rank test) or the two post-PCI groups (χ = 2.83, P = .093, and log-rank test). However, in a multivariable Cox regression model, landmark analysis showed that the patients in high level group of post-PCI, not pre-PCI, were associated with remarkable higher risks of cardiovascular events compared to the low level group during the first 1.5 years of follow-up (adjusted HR = 9.99, 95%CI = 1.99-50.13, P = .005). However, that was of no significance from 1.5 years to maximum follow-up years (adjusted HR = 0.82, 95%CI = 0.26-2.59, P = .733).High Ang-2 levels of post-PCI can predict the occurrence of cardiovascular events in the short to medium term.

Association of carotid atherosclerosis and stiffness with abdominal aortic aneurysm: The atherosclerosis risk in communities (ARIC) study

BACKGROUND AND AIMS

Individuals with atherosclerosis and stiffness often have increased abdominal aortic diameters, but prospective evidence linking them to the risk of abdominal aortic aneurysm (AAA) is limited.

METHODS

We prospectively examined the relationship of carotid atherosclerosis and stiffness with future risk of AAA in ARIC. At Visits 1 (1987-89) or 2 (1990-1992), we assessed carotid atherosclerosis (represented by greater carotid intima-media thickness [cIMT] or presence of atherosclerotic plaque) and lower carotid distensibility (reflected by a higher carotid Beta Index). We identified incident, clinical AAAs during follow-up through 2011 using hospital discharge codes, Medicare outpatient diagnoses, or death certificates.

RESULTS

Participants' mean age at baseline was 54.2 years (SD 5.8), 45% were male and 73% white. During a median of 22.5 years of follow-up, 542 clinical AAAs were ascertained. After multivariable adjustment, the presence of carotid atherosclerotic plaque at baseline was associated with 1.31 (95% CI: 1.10-1.57; p = 0.003) times higher risk of clinical AAA. Greater cIMT and Beta Index were also associated with clinical AAA with a dose-response across quartiles (p trend for both: 0.006; hazard ratios [95% CI] for the highest vs. lowest quartiles: 1.55 [1.13-2.11] and 1.68 [1.16-2.43], respectively). The associations of cIMT and Beta Index with AAA were independent of each other.

CONCLUSIONS

This prospective population-based study found that indices of greater carotid atherosclerosis and lower carotid distensibility are markers of increased AAA risk.

Association of high sensitivity C-reactive protein and abdominal aortic aneurysm: a meta-analysis and systematic review

OBJECTIVE

To evaluate the association of high sensitivity C-reactive protein (hsCRP) with the presence of abdominal aortic aneurysm (AAA).

METHODS

Medline, Cochrane, Embase, and Google Scholar databases were searched until 22 June 2016 using the keywords predictive factors, biomarkers, abdominal aortic aneurysm, prediction, high sensitivity C-reactive protein, and hsCRP. Prospective studies, retrospective studies, and cohort studies were included.

RESULTS

Twelve case-control studies were included in the meta-analysis with a total of 8345 patients (1977 in the AAA group and 6368 in the control group). The pooled results showed that AAA patients had higher hsCRP value than the control group (difference in means = 1.827, 95% CI = 0.010 to 3.645, p = .049). Subgroup analysis found AAA patients with medium or small aortic diameter (<50 mm) had higher hsCRP plasma levels than the control group (difference in means = 1.301, 95% CI = 0.821 to 1.781, p < .001). In patients with large aortic diameter (≥50 mm), no difference was observed in hsCRP levels between the AAA and control groups (difference in means = 1.769, 95% CI = -1.387 to 4.925, p = .272). Multi-regression analysis found the difference in means of hsCRP plasma levels between AAA and control groups decreased as aortic diameter increased (slope = -0.04, p < .001), suggesting that hsCRP levels may be inversely associated with increasing aneurysm size.

CONCLUSIONS

Our findings suggest that hsCRP levels may possibly be used as a diagnostic biomarker for AAA patients with medium or small aortic diameter but not for AAA patients with large aortic diameter. The correlation between serum hsCRP level and AAA aneurysm is not conclusive due to the small number of included articles and between-study heterogeneity.

Efficacy of brief behavioral counselling by allied health professionals to promote physical activity in people with peripheral arterial disease (BIPP): study protocol for a multi-center randomized controlled trial

Background

Physical activity is recommended for people with peripheral arterial disease (PAD), and can improve walking capacity and quality of life; and reduce pain, requirement for surgery and cardiovascular events. This trial will assess the efficacy of a brief behavioral counselling intervention delivered by allied health professionals to improve physical activity in people with PAD.

Methods

This is a multi-center randomised controlled trial in four cities across Australia. Participants (N = 200) will be recruited from specialist vascular clinics, general practitioners and research databases and randomised to either the control or intervention group. Both groups will receive usual medical care, a written PAD management information sheet including advice to walk, and four individualised contacts from a protocol-trained allied health professional over 3 months (weeks 1, 2, 6, 12). The control group will receive four 15-min telephone calls with general discussion about PAD symptoms and health and wellbeing. The intervention group will receive behavioral counselling via two 1-h face-to-face sessions and two 15-min telephone calls. The counselling is based on the 5A framework and will promote interval walking for 3 × 40 min/week. Assessments will be conducted at baseline, and 4, 12 and 24 months by staff blinded to participant allocation. Objectively assessed outcomes include physical activity (primary), sedentary behavior, lower limb body function, walking capacity, cardiorespiratory fitness, event-based claudication index, vascular interventions, clinical events, cardiovascular function, circulating markers, and anthropometric measures. Self-reported outcomes include physical activity and sedentary behavior, walking ability, pain severity, and health-related quality of life. Data will be analysed using an intention-to-treat approach. An economic evaluation will assess whether embedding the intervention into routine care would likely be value for money. A cost-effectiveness analysis will estimate change in cost per change in activity indicators due to the intervention, and a cost-utility analysis will assess change in cost per quality-adjusted life year. A full uncertainty analysis will be undertaken, including a value of information analysis, to evaluate the economic case for further research.

Discussion

This trial will evaluate the efficacy and cost-effectiveness of a brief behavioral counselling intervention for a common cardiovascular disease with significant burden.

Trial registration

ACTRN 12614000592640 Australian New Zealand Clinical Trials Registry. Registration Date 4 June 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-016-3801-7) contains supplementary material, which is available to authorized users.

Angiopoietin-2 attenuates angiotensin II-induced aortic aneurysm and atherosclerosis in apolipoprotein E-deficient mice

Angiogenesis and inflammation are implicated in aortic aneurysm and atherosclerosis and regulated by angiopoietin-2 (Angpt2). The effect of Angpt2 administration on experimental aortic aneurysm and atherosclerosis was examined. Six-month-old male apolipoprotein E deficient (ApoE^-/-) mice were infused with angiotensin II (AngII) and administered subcutaneous human Fc-protein (control) or recombinant Angpt2 (rAngpt2) over 14 days. Administration of rAngpt2 significantly inhibited AngII-induced aortic dilatation and rupture of the suprarenal aorta (SRA), and development of atherosclerosis within the aortic arch. These effects were blood pressure and plasma lipoprotein independent and associated with Tie2 activation and down-regulation of monocyte chemotactic protein-1 (MCP-1) within the SRA. Plasma concentrations of MCP-1 and interleukin-6 were significantly lower in mice receiving rAngpt2. Immunostaining for the monocyte/macrophage marker MOMA-2 and the angiogenesis marker CD31 within the SRA were less in mice receiving rAngpt2 than controls. The percentage of inflammatory (Ly6C^hi) monocytes within the bone marrow was increased while that in peripheral blood was decreased by rAngpt2 administration. In conclusion, administration of rAngpt2 attenuated angiotensin II-induced aortic aneurysm and atherosclerosis in ApoE^-/- mice associated with reduced aortic inflammation and angiogenesis. Up-regulation of Angpt2 may have potential therapeutic value in patients with aortic aneurysm and atherosclerosis.

Prognostic value of angiopoietin-2 in patients with chronic heart failure

PURPOSE

The analysis of biomarkers with a prognostic value in chronic heart failure (CHF) is in constant progress. This study aimed to evaluate the short-term prognostic value of angiopoietin-2 (Ang2), galectin-3 (Gal-3), myeloperoxidase (MPO), endostatin (End), and pro-brain natriuretic peptide (pro-BNP) as a conventionally accepted prognosis biomarker in CHF patients.

METHODS AND RESULTS

146 consecutive patients with CHF due to left ventricular systolic dysfunction (LVEF<40% at echocardiography) were enrolled, and underwent serum/blood sample analysis after 12-h fasting. Within 1year, 25 (17%) patients died (D) or underwent heart transplantation (HT). D+HT patients showed higher values of Ang2 (Log Ang2: 8.97±0.52 vs. 8.45±0.69, p=0.0004), myeloperoxidase (MPO) (Log MPO: 5±1.1 vs. 4.2±1.3, p=0.005) and pro-BNP (Log pro-BNP: 8.70±0.9 vs. 7.45±1.3, p<0.00001). At univariate Cox regression, pro-BNP and Ang2 were the best predictors of 1-year mortality, with area under the curve (AUC)=0.78 for pro-BNP (68% sensitivity and 82% specificity to predict outcome for a cut-off value of 5109pg/mL, 95% confidence interval [CI] 0.70-0.85, p<0.0001) and AUC=0.73 for Ang2 (84% sensitivity and 61% specificity to predict outcome for a cut-off value of 5175pg/mL, 95% CI 0.65-0.80, p<0.0001). At multivariate analysis, pro-BNP was the only predictor of one-year D/HT.

CONCLUSION

In our series of CHF patients, Ang2 and pro-BNP showed the best predictive value for 1-year outcome, while only pro-BNP could independently predict D/HT.

Angiopoietin-2 blocking antibodies reduce early atherosclerotic plaque development in mice

OBJECTIVE

Angiopoietin-2 (Ang-2) blocking agents are currently undergoing clinical trials for use in cancer treatment. Ang-2 has also been associated with rupture-prone atherosclerotic plaques in humans, suggesting a role for Ang-2 in plaque stability. Despite the availability of Ang-2 blocking agents, their clinical use is still lacking. Our aim was to establish if Ang-2 has a role in atheroma development and in the transition of subclinical to clinically relevant atherosclerosis. We investigated the effect of antibody-mediated Ang-2 blockage on atherogenesis after in a mouse model of atherosclerosis.

METHODS

Hypercholesterolemic (low-density lipoprotein receptor(-/-) apolipoprotein B(100/100)) mice were subjected to high-cholesterol diet for eight weeks, one group with and one group without Ang-2 blocking antibody treatment during weeks 4-8.To enhance plaque development, a peri-adventitial collar was placed around the carotid arteries at the start of antibody treatment. Aortic root, carotid arteries and brachiocephalic arteries were analyzed to evaluate the effect of Ang-2 blockage on atherosclerotic plaque size and stable plaque characteristics.

RESULTS

Anti-Ang-2 treatment reduced the size of fatty streaks in the brachiocephalic artery (-72%, p < 0.05). In addition, antibody-mediated Ang-2 blockage reduced plasma triglycerides (-27%, p < 0.05). In contrast, Ang-2 blockage did not have any effect on the size or composition (collagen content, macrophage percentage, adventitial microvessel density) of pre-existing plaques in the aortic root or collar-induced plaques in the carotid artery.

CONCLUSIONS

Ang-2 blockage was beneficial as it decreased fatty streak formation and plasma triglyceride levels, but had no adverse effect on pre-existing atherosclerosis in hypercholesterolemic mice.

Association of circulating angiogenesis inhibitors and asymmetric dimethyl arginine with coronary plaque burden

BACKGROUND

Chronic kidney disease (CKD) is an independent risk factor for the development and severity of coronary artery disease (CHD) and endothelial dysfunction. There is an increase in the circulating angiogenesis inhibitors endostatin (END), thrombospondin-2 (TSP), angiopoietin-2 (ANG) and the nitric oxide (NO) inhibitor asymmetric dimethyl arginine (ADMA) in CKD patients. The aim of this study was to evaluate associations of the serum level of these factors and of the related angiogenesis inhibitor, endoglin (ENG), with burden of coronary atherosclerosis.

METHODS

One hundred twenty-two patients undergoing coronary angiography were recruited from the cardiac catheterization lab at a single center. The total burden of coronary plaque (mm(2)) and the presence of coronary collaterals were quantified using quantitative coronary angiography (QCA). Serum levels of angiogenesis inhibitors were measured by ELISA (ENG, END, and ANG), Luminex assay (TSP), or HLPC (ADMA), respectively. Associations with plaque burden and coronary collateral supply were analyzed in multi-variable linear and logistic regression models.

RESULTS

There was no significant association found between levels of circulating ADMA, ENG, END, ANG, or TSP and coronary plaque burden or collateral formation.

CONCLUSIONS

Our findings suggest that associations of circulating END, ENG, TSP, and ANG with cardiovascular mortality are unlikely to be mediated via direct effects on coronary plaque formation or by inhibition of collateral formation. Whether associations of these factors with mortality are mediated via local concentrations, myocardial tissue, or intra-plaque expression of these factors or by an effect on plaque vulnerability merits additional investigation.

Circulating Angiopoietin-2 levels predict mortality in kidney transplant recipients: a 4-year prospective case-cohort study

Angiopoietin 2 (Angpt2) impairs endothelial function by preventing angiopoietin 1 from binding to their common endothelial-specific receptor Tie2. Here, we examined whether circulating Angpt2 predicts outcome in kidney transplant recipients. For this case-cohort study, we selected 130 kidney transplant recipients who had died or returned to dialysis within the first 2 years of follow-up of our cohort study, as well as 130 age- and gender-matched kidney transplant recipients without an event (controls) from a total of 993 kidney transplant recipients. The total of 260 selected patients were followed in median 4 years. Serum Angpt2 at baseline was measured using an in-house immunoluminometric assay. Median Angpt2 concentrations were significantly higher in patients who died [median (interquartile range--IQR) 3.6 (2.8-5.9) ng/ml] as compared to patients who did not die during the study period [2.8 (2.1-4.1) ng/ml; P < 0.001]. Ln (natural log) Angpt2 levels correlated positively with C-reactive protein levels (r = 0.315, P < 0.001) and the Charlson Comorbidity Index (r = 0.188, P = 0.002) and were inversely associated with eGFR (r = -0.301, P < 0.001) hemoglobin (r = -0.269, P < 0.001), and serum albumin concentrations (r = -0.382, P < 0.001). On multivariate analyses, baseline Angpt2 levels independently predicted all-cause mortality (multivariable-adjusted hazard ratio associated with one natural log unit higher Angpt2 level: 1.70 (95% confidence interval: 1.10-2.61)). In our analysis, circulating Angpt2 was an independent predictor of all-cause mortality in stable, prevalent kidney transplant recipients.

A decline in glomerular filtration rate rather than renal arterial stenotic lesions, per se, predicts cardiovascular-renal events in type 2 diabetic patients

BACKGROUND

In diabetic patients with renal artery arteriosclerosis (RAAS), the factors associated with a greater risk for cardiovascular-renal events (CVREs) remain unclear: the decline in estimated glomerular filtration rate (eGFR) caused by RAAS or the advance of arteriosclerosis that causes RAAS. Hence, the features to determine which best predicts the onset of CVREs in such patients were compared.

METHODS AND RESULTS

The renal arteries of 162 type 2 diabetes patients were assessed by using magnetic resonance angiography (RAAS diagnosed as arteriosclerotic stenosis ≥50%) and they were studied longitudinally over 7 years. The influence of the presence/absence of RAAS, a decline in eGFR, clinical factors, surrogate arteriosclerotic markers and ischemic markers on patient's CVREs were assessed. A Cox regression analysis showed the detection of RAAS to be an independent risk factor for CVREs (bilateral RAAS was an extremely strong risk factor for the development of CVREs within 1,000 days), as was the decline in eGFR in a logistic regression analysis; the latter being a more powerful risk factor for CVREs. A multiple regression analysis revealed angiopoietin-2, a marker of ischemia, to be a risk factor for the decline in eGFR.

CONCLUSIONS

A decline in renal function but not the renal arterial stenotic lesion itself appears to be associated with an increased incidence of CVREs in type 2 diabetic patients with RAAS.