Sex-dependent expression of galectin-1, a cardioprotective β-galactoside-binding lectin, in human calcific aortic stenosis

We aimed to analyze sex-related differences in galectin-1 (Gal-1), a β-galactoside-binding lectin, in aortic stenosis (AS) and its association with the inflammatory and fibrocalcific progression of AS. Gal-1 was determined in serum and aortic valves (AVs) from control and AS donors by western blot and immunohistochemistry. Differences were validated by ELISA and qPCR in AS samples. In vitro experiments were conducted in primary cultured valve interstitial cells (VICs). Serum Gal-1 was not different neither between control and AS nor between men and women. There was no association between circulating and valvular Gal-1 levels. The expression of Gal-1 in stenotic AVs was higher in men than women, even after adjusting for confounding factors, and was associated with inflammation, oxidative stress, extracellular matrix remodeling, fibrosis, and osteogenesis. Gal-1 (LGALS1) mRNA was enhanced within fibrocalcific areas of stenotic AVs, especially in men. Secretion of Gal-1 was up-regulated over a time course of 2, 4, and 8 days in men's calcifying VICs, only peaking at day 4 in women's VICs. In vitro, Gal-1 was associated with similar mechanisms to those in our clinical cohort. β-estradiol significantly up-regulated the activity of an LGALS1 promoter vector and the secretion of Gal-1, only in women's VICs. Supplementation with rGal-1 prevented the effects elicited by calcific challenge including the metabolic shift to glycolysis. In conclusion, Gal-1 is up-regulated in stenotic AVs and VICs from men in association with inflammation, oxidative stress, matrix remodeling, and osteogenesis. Estrogens can regulate Gal-1 expression with potential implications in post-menopause women. Exogenous rGal-1 can diminish calcific phenotypes in both women and men.

Atherosclerosis and Other Related-Arterial Diseases

Cardiovascular diseases (CVD) are a major cause of morbidity and mortality worldwide, accounting for more than 17 million deaths each year [...].

Protection of diabetes in aortic abdominal aneurysm: Are antidiabetics the real effectors?

Aortic aneurysms, including abdominal aortic aneurysms (AAAs), is the second most prevalent aortic disease and represents an important cause of death worldwide. AAA is a permanent dilation of the aorta on its infrarenal portion, pathologically associated with oxidative stress, proteolysis, vascular smooth muscle cell loss, immune-inflammation, and extracellular matrix remodeling and degradation. Most epidemiological studies have shown a potential protective role of diabetes mellitus (DM) on the prevalence and incidence of AAA. The effect of DM on AAA might be explained mainly by two factors: hyperglycemia [or other DM-related factors such as insulin resistance (IR)] and/or by the effect of prescribed DM drugs, which may have a direct or indirect effect on the formation and progression of AAAs. However, recent studies further support that the protective role of DM in AAA may be attributable to antidiabetic therapies (i.e.: metformin or SGLT-2 inhibitors). This review summarizes current literature on the relationship between DM and the incidence, progression, and rupture of AAAs, and discusses the potential cellular and molecular pathways that may be involved in its vascular effects. Besides, we provide a summary of current antidiabetic therapies which use could be beneficial for AAA.

Annexins and cardiovascular diseases: Beyond membrane trafficking and repair

Cardiovascular diseases (CVD) remain the leading cause of mortality worldwide. The main cause underlying CVD is associated with the pathological remodeling of the vascular wall, involving several cell types, including endothelial cells, vascular smooth muscle cells, and leukocytes. Vascular remodeling is often related with the development of atherosclerotic plaques leading to narrowing of the arteries and reduced blood flow. Atherosclerosis is known to be triggered by high blood cholesterol levels, which in the presence of a dysfunctional endothelium, results in the retention of lipoproteins in the artery wall, leading to an immune-inflammatory response. Continued hypercholesterolemia and inflammation aggravate the progression of atherosclerotic plaque over time, which is often complicated by thrombus development, leading to the possibility of CV events such as myocardial infarction or stroke. Annexins are a family of proteins with high structural homology that bind phospholipids in a calcium-dependent manner. These proteins are involved in several biological functions, from cell structural organization to growth regulation and vesicle trafficking. In vitro gain- or loss-of-function experiments have demonstrated the implication of annexins with a wide variety of cellular processes independent of calcium signaling such as immune-inflammatory response, cell proliferation, migration, differentiation, apoptosis, and membrane repair. In the last years, the use of mice deficient for different annexins has provided insight into additional functions of these proteins in vivo, and their involvement in different pathologies. This review will focus in the role of annexins in CVD, highlighting the mechanisms involved and the potential therapeutic effects of these proteins.

Complement C5 plasma levels are associated to abdominal aortic aneurysm prevalence and progression

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Complemento II-CM

La Caixa

Aim

Previous human and experimental studies have suggested a role of complement activation in abdominal aortic aneurysm (AAA).  We recently described an increase in complement C5 levels in plasma of subjects with subclinical atherosclerosis (1). Our aim was to investigate the potential association of C5 with AAA presence and progression.

Material and methods

Tissue and tissue-conditioned media from AAA (thrombus and wall) or healthy samples were obtained from surgical repair or brain-deceased organ donors, respectively. Blood samples from 490 AAA patients (maximal aortic diameter ≥30 mm) were obtained within a population-based ultrasound-screening trial in Danish men and from 176 age-matched screened negative controls. C5 protein levels were assessed by immunohistochemistry and ELISA.

Results

High C5 positive immunostaining was observed in AAA thrombus and media, while the staining in healthy arteries was faint. C5 levels were higher in tissue-conditioned media from AAA thrombus and AAA media as compared to healthy arteries (7.1±1 vs 2.9 ±0.5 vs 1.2±0.2ug/ml, p<0.0001 for both). C5 plasma levels in AAA patients were higher than in controls (116±8 vs 61±7 ug/ml, P<0.001). AAA patients at the upper tertile of C5 at baseline had a 25% higher risk of needing surgical repair during the follow-up (Hazard Ratio=1.25, 95% confidence interval, 1.045;1.511, P<0.05).

Conclusions

C5 is associated to AAA presence and progression suggesting its potential use as a prognostic marker. Future studies are needed to clarify the pathogenic role of C5 in AAA.

Galectin-1 prevents pathological vascular remodeling in atherosclerosis and abdominal aortic aneurysm

Pathological vascular remodeling is the underlying cause of atherosclerosis and abdominal aortic aneurysm (AAA). Here, we analyzed the role of galectin-1 (Gal-1), a β-galactoside-binding protein, as a therapeutic target for atherosclerosis and AAA. Mice lacking Gal-1 (Lgals1^-/-) developed severe atherosclerosis induced by pAAV/D377Y-mPCSK9 adenovirus and displayed higher lipid levels and lower expression of contractile markers of vascular smooth muscle cells (VSMCs) in plaques than wild-type mice. Proteomic analysis of Lgals1^-/- aortas showed changes in markers of VSMC phenotypic switch and altered composition of mitochondrial proteins. Mechanistically, Gal-1 silencing resulted in increased foam cell formation and mitochondrial dysfunction in VSMCs, while treatment with recombinant Gal-1 (rGal-1) prevented these effects. Furthermore, rGal-1 treatment attenuated atherosclerosis and elastase-induced AAA, leading to higher contractile VSMCs in aortic tissues. Gal-1 expression decreased in human atheroma and AAA compared to control tissue. Thus, Gal-1-driven circuits emerge as potential therapeutic strategies in atherosclerosis and AAA.

Impact of renal function on the prognostic value of mineral metabolism in patients with chronic ischaemic heart disease patients with chronic ischaemic heart disease

BACKGROUND

Parathormone (PTH) is a component of the Mineral Metabolism (MM) system that has been shown recently to add prognostic value in pts. with stable coronary artery disease (SCAD) and average renal function. However, the influence of renal function on the prognostic role of PTH in pts. with SCAD has not been shown yet.

PURPOSE

To assess the influence of estimated glomerular filtration rate (eGFR) on the prognostic role of PTH and other MM markers in pts. with SCAD.

METHODS

We analyzed the prognostic value of MM markers (PTH, klotho, phosphate, calcidiol [25-hydroxyvitamin D], and fibroblast growth factor-23 [FGF23]) in 964 pts. with SCAD and eGFR<60ml/min/1.73 m² (LGFR) vs pts. with eGFR≥60ml/min/1.73 m² (HGFR) included in five hospitals of Madrid. The main outcome was the combination of death with ischemic events (any acute coronary syndrome, ischemic stroke or transient ischemic attack). eGFR was calculated by the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI).

RESULTS

Age was 60.0 (52.0-72.0) years, 76.2% of patients were men, and eGFR was 80.4 (65.3-93.1) ml/min/1,73 m². Median follow-up was 5.39 (2.81-6.92) years. There were 790 pts. with HGFR and 174 with LGFR. In HGFR pts., predictors of ischemic events or death were plasma levels of calcidiol [HR=0.023 (0.94-0.99) p=0.023], FGF23 [HR=1.00 (1.00-1.003) p=0.036], non-HDL cholesterol [HR=1.01 (1.00-1.01) p=0.026] and high sensitivity troponin I [HR=5.12 (1.67-15.59) p=0.004], along with age [HR=1.03 (1.01-1.05) p=0.01], treatment with statins [HR=0.36 (0.19-0.68) p=0.002], nitrates [HR=1.13 (1.07-2.79) p=0.027], dihydropyridines [HR=1.71 (1.05-2.77) p=0.032], verapamil [HR=5.71 (1.35-24.1) p=0.018], and proton-pump inhibitors [HR=2.23 (1.36-3.68) p= 0.002]. In the LGFR subgroup, predictors of death or ischemic events were PTH plasma levels, [HR=1.01 (1.00-1.01) p=0.005], eGFR [HR=0.96 (0.94-0.99) p=0.004], age [HR=1.06 (1.02-1.10) p=0.003], caucasian race [HR=0.04 (0.004-0.380) p=0.005], and treatment with insulin [HR=2.6 (1.20-5.63) p=0.015].

CONCLUSIONS

In pts. with SCAD, PTH is an independent predictor of poor outcomes only in those with eGFR<60ml/min/1.73 m², while in pts. with eGFR≥60ml/min/1.73 m² calcidiol and FGF23 become the only components of MM that may predict prognosis. Then, renal function influences the predictive power of MM markers in pts. with SCAD.

N-Terminal Pro-Brain Natriuretic Peptide Plasma Levels Are Associated with Intermediate-Term Follow-Up Cancer in Coronary Patients

N-terminal pro-brain natriuretic peptide (NT-proBNP) plasma levels are increased in patients with cancer. In this paper, we test whether NT-proBNP may identify patients who are going to receive a future cancer diagnosis (CD) in the intermediate-term follow-up. We studied 962 patients with stable coronary artery disease and free of cancer and heart failure at baseline. This sample represents a re-analysis of a previous work expanding the sample size and the follow-up. NT-proBNP, galectin-3, monocyte chemoattractant protein-1, high-sensitivity C-reactive protein, high-sensitivity cardiac troponin I (hsTnI), and calcidiol (vitamin D) plasma levels were assessed. The primary outcome was new CD. After 5.40 (2.81–6.94) years of follow-up, 59 patients received a CD. NT-proBNP [HR 1.036 CI (1.015–1.056) per increase in 100 pg/mL; p = 0.001], previous atrial fibrillation (HR 3.140 CI (1.196–8.243); p = 0.020), and absence of previous heart failure (HR 0.067 CI (0.006–0.802); p = 0.033) were independent predictors of receiving a CD in the first three years of follow-up. None of the variables analyzed predicted a CD beyond this time. The number of patients developing heart failure during follow-up was 0 (0.0%) in patients receiving CD in the first three years of follow-up, 2 (6.9%) in those receiving a CD diagnosis beyond this time, and 40 (4.4%) in patients not developing cancer (p = 0.216). These numbers suggest that future heart failure was not a confounding factor. In patients with coronary artery disease, NT-proBNP was an independent predictor of CD in the first three years of follow-up but not later, suggesting that it could be detecting subclinical undiagnosed cancers.

Parathormone levels add prognostic ability to N-terminal pro-brain natriuretic peptide in stable coronary patients

Aims

There are controversial data on the ability of the components of mineral metabolism (vitamin D, phosphate, parathormone [PTH], fibroblast growth factor‐23 [FGF23], and klotho) to predict cardiovascular events. In addition, it is unknown whether they add any prognostic value to other well‐known biomarkers.

Methods and results

In 969 stable coronary patients, we determined plasma levels of all the aforementioned components of mineral metabolism with a complete set of clinical and biochemical variables, including N‐terminal pro‐brain natriuretic peptide (NT‐proBNP), high‐sensitivity troponin I (hs‐TnI), and high‐sensitivity C‐reactive protein. Secondary outcomes were ischaemic events (any acute coronary syndrome, stroke, or transient ischaemic attack) and heart failure or death. The primary outcome was a composite of the secondary outcomes. Median follow‐up was 5.39 years. Age was 60 (52–72) years. Median glomerular filtration rate was 80.4 (65.3–93.1) mL/min/1.73 m². One‐hundred and eighty‐five patients developed the primary outcome. FGF23, PTH, hs‐TnI, and NT‐proBNP were directly related with the primary outcome on univariate Cox analysis, while Klotho and calcidiol were inversely related. On multivariate analysis, only PTH (HR 1.058 [CI 1.021–1.097]; P = 0.002) and NT‐proBNP (HR 1.020 [CI 1.012–1.028]; P < 0.001) were independent predictors of the primary outcome but also for the secondary outcome of heart failure or death (HR 1.066 [CI 1.016–1.119]; P = 0.009 and HR 1.024 [CI 1.014–1.034]; P < 0.001, respectively). PTH was the only biomarker that predicted ischaemic events (HR 1.052 [1.010–1.096]; P = 0.016). Patients were divided in two subgroups according to FGF23 plasma levels. PTH retained its prognostic value only in patients with FGF23 levels above the median (>85.5 RU/mL) (P < 0.001) but not in patients with low FGF23 levels (P = 0.551). There was a significant interaction between FGF23 and PTH (P = 0.002). However, there was no significant interaction between PTH and both klotho and calcidiol levels.

Conclusions

Parathormone is an independent predictor of cardiovascular events in coronary patients, adding complimentary prognostic information to NT‐proBNP plasma levels. This predictive value is restricted to patients with high FGF23 plasma levels. This should be considered in the design of future studies in this field.

MCP-1 Predicts Recurrent Cardiovascular Events in Patients with Persistent Inflammation

Clinical data indicate that patients with C-reactive protein (CRP) levels higher than 2 mg per liter suffer from persistent inflammation, which is associated with high risk of cardiovascular disease (CVD). We determined whether a panel of biomarkers associated with CVD could predict recurrent events in patients with low or persistent inflammation and coronary artery disease (CAD). We followed 917 patients with CAD (median 4.59 ± 2.39 years), assessing CRP, galectin-3, monocyte chemoattractant protein-1 (MCP-1), N-terminal fragment of brain natriuretic peptide (NT-proBNP) and troponin-I plasma levels. The primary outcome was the combination of cardiovascular events (acute coronary syndrome, stroke or transient ischemic event, heart failure or death). Patients with persistent inflammation (n = 343) showed higher NT-proBNP and MCP-1 plasma levels compared to patients with CRP < 2 mg/L. Neither MCP-1 nor NT-proBNP was associated with primary outcome in patients with CRP < 2 mg/L. However, NT-proBNP and MCP-1 plasma levels were associated with increased risk of the primary outcome in patients with persistent inflammation. When patients were divided by type of event, MCP-1 was associated with an increased risk of acute ischemic events. A significant interaction between MCP-1 and persistent inflammation was found (synergy index: 6.17 (4.39–7.95)). In conclusion, MCP-1 plasma concentration is associated with recurrent cardiovascular events in patients with persistent inflammation.

CD163 deficiency increases foam cell formation and plaque progression in atherosclerotic mice

Atherosclerosis is an inflammatory disease characterized by the accumulation of macrophages in the vessel wall. Macrophages depend on their polarization to exert either pro-inflammatory or anti-inflammatory effects. Macrophages of the anti-inflammatory phenotype express high levels of CD163, a scavenger receptor for the hemoglobin-haptoglobin complex. CD163 can also bind to the pro-inflammatory cytokine TWEAK. Using ApoE-deficient or ApoE/CD163 double-deficient mice we aim to investigate the involvement of CD163 in atherosclerosis development and its capacity to neutralize the TWEAK actions. ApoE/CD163 double-deficient mice displayed a more unstable plaque phenotype characterized by an increased lipid and macrophage content, plaque size, and pro-inflammatory cytokine expression. In vitro experiments demonstrated that the absence of CD163 in M2-type macrophages-induced foam cell formation through upregulation of CD36 expression. Moreover, exogenous TWEAK administration increased atherosclerotic lesion size, lipids, and macrophages content in ApoE^-/- /CD163^-/- compared with ApoE^-/- /CD163^+/+ mice. Treatment with recombinant CD163 was able to neutralize the proatherogenic effects of TWEAK in ApoE/CD163 double-deficient mice. Recombinant CD163 abolished the pro-inflammatory actions of TWEAK on vascular smooth muscle cells, decreasing NF-kB activation, cytokines and metalloproteinases expression, and macrophages migration. In conclusion, CD163-expressing macrophages serve as a protective mechanism to prevent the deleterious effects of TWEAK on atherosclerotic plaque development and progression.

Galectin-3 Is Associated with Cardiovascular Events in Post-Acute Coronary Syndrome Patients with Type-2 Diabetes

Introduction: Type-2 diabetes mellitus (T2DM) is associated with early and severe atherosclerosis. However, few biomarkers can predict cardiovascular events in this population. Methods: We followed 964 patients with coronary artery disease (CAD), assessing plasma levels of galectin-3, monocyte chemoattractant protein-1 (MCP-1), and N-terminal fragment of brain natriuretic peptide (NT-proBNP) at baseline. The secondary outcomes were acute ischemia and heart failure or death. The primary outcome was the combination of the secondary outcomes. Results. Two hundred thirty-two patients had T2DM. Patients with T2DM showed higher MCP-1 (144 (113–195) vs. 133 (105–173) pg/mL, p = 0.006) and galectin-3 (8.3 (6.5–10.5) vs. 7.8 (5.9–9.8) ng/mL, p = 0.049) levels as compared to patients without diabetes. Median follow-up was 5.39 years (2.81–6.92). Galectin-3 levels were associated with increased risk of the primary outcome in T2DM patients (Hazard ratio (HR) 1.57 (1.07–2.30); p = 0.022), along with a history of cerebrovascular events. Treatment with clopidogrel was associated with lower risk. In contrast, NT-proBNP and MCP-1, but not galectin-3, were related to increased risk of the event in nondiabetic patients (HR 1.21 (1.04–1.42); p = 0.017 and HR 1.23 (1.05–1.44); p = 0.012, respectively), along with male sex and age. Galectin-3 was also the only biomarker associated with the development of acute ischemic events and heart failure or death in T2DM patients, while, in nondiabetics, MCP-1 and NT-proBNP, respectively, were related to these events. Conclusion: In CAD patients, galectin-3 plasma levels are associated with cardiovascular events in patients with T2DM, and MCP-1 and NT-proBNP in those without T2DM.

A major role of TWEAK/Fn14 axis as a therapeutic target for post-angioplasty restenosis

Background

Tumor necrosis factor-like weak inducer of apoptosis (Tnfsf12; TWEAK) and its receptor Fibroblast growth factor-inducible 14 (Tnfrsf12a; Fn14) participate in the inflammatory response associated with vascular remodeling. However, the functional effect of TWEAK on vascular smooth muscle cells (VSMCs) is not completely elucidated.

Methods

Next generation sequencing-based methods were performed to identify genes and pathways regulated by TWEAK in VSMCs. Flow-citometry, wound-healing scratch experiments and transwell migration assays were used to analyze VSMCs proliferation and migration. Mouse wire injury model was done to evaluate the role of TWEAK/Fn14 during neointimal hyperplasia.

Findings

TWEAK up-regulated 1611 and down-regulated 1091 genes in VSMCs. Using a gene-set enrichment method, we found a functional module involved in cell proliferation defined as the minimal network connecting top TWEAK up-regulated genes. In vitro experiments in wild-type or Tnfrsf12a deficient VSMCs demonstrated that TWEAK increased cell proliferation, VSMCs motility and migration. Mechanistically, TWEAK increased cyclins (cyclinD1), cyclin-dependent kinases (CDK4, CDK6) and decreased cyclin-dependent kinase inhibitors (p15^lNK4B) mRNA and protein expression. Downregulation of p15^INK4B induced by TWEAK was mediated by mitogen-activated protein kinase ERK and Akt activation.

Tnfrsf12a or Tnfsf12 genetic depletion and pharmacological intervention with TWEAK blocking antibody reduced neointimal formation, decreasing cell proliferation, cyclin D1 and CDK4/6 expression, and increasing p15^INK4B expression compared with wild type or IgG-treated mice in wire-injured femoral arteries. Finally, immunohistochemistry in human coronary arteries with stenosis or in-stent restenosis revealed high levels of Fn14, TWEAK and PCNA in VSMCs enriched areas of the neointima as compared with healthy coronary arteries.

Interpretation

Our data define a major role of TWEAK/Fn14 in the control of VSMCs proliferation and migration during neointimal hyperplasia after wire injury in mice, and identify TWEAK/Fn14 as a potential target for treating in-stent restenosis.

Fund

ISCiii-FEDER, CIBERCV and CIBERDEM.

Combination of biomarkers of vascular calcification and sTWEAK to predict cardiovascular events in chronic kidney disease

BACKGROUND AND AIMS

Vascular calcification (VC) and atherosclerosis are associated with an increased cardiovascular morbimortality in chronic kidney disease (CKD). Osteoprotegerin (OPG) and osteopontin (OPN) are involved in both VC and CKD. Soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) has been related to cardiovascular disease. We hypothesized that OPG, OPN and sTWEAK levels may be associated with a higher prevalence of cardiovascular outcomes in patients with CKD.

METHODS

The presence of calcified or non-calcified atherosclerotic plaques was assessed in 1043 stage 3 to 5D CKD patients from The NEFRONA Study. Biochemical measurements and OPG, OPN and sTWEAK serum levels were analyzed. Patients were followed for cardiovascular outcomes (41 ± 16 months).

RESULTS

At recruitment, 26% of CKD patients had VC. The adjusted odds ratios for having VC were 2.22 (1.32-3.75); p=.003 for OPG, and 0.45 (0.24-0.84); p=.01 for sTWEAK concentrations. After follow-up, 95 CV events occurred. In a Cox model, patients with OPG or OPN above and sTWEAK below their optimal cut-off points had an adjusted higher risk of cardiovascular events [HR: 2.10 (1.49-3.90); p=.02; 1.65 (1.02-2.65); p=.04; 2.05 (1.28-3.29), p=.003; respectively]. When CKD patients were grouped according to the number of biomarkers above (OPG and OPN) or below (sTWEAK) their cut-off points, the combination of these biomarkers showed the highest risk for cardiovascular events [HR: 9.46 (3.80-23.5) p < .001]. A composite score of these three biomarkers increased the C-statistic and net reclassification index beyond conventional risk factors and VC.

CONCLUSIONS

The combination of OPG, OPN and sTWEAK increased the predictability of cardiovascular outcomes.

From tissue iron retention to low systemic haemoglobin levels, new pathophysiological biomarkers of human abdominal aortic aneurysm

Iron deposits are observed in tissue of abdominal aortic aneurysm (AAA) patients, although the underlying mechanisms are not completely elucidated. Therefore we explored circulating markers of iron metabolism in AAA patients, and tested if they could serve as biomarkers of AAA. Increased red blood cell (RBC)-borne iron retention and transferrin, transferrin receptor and ferritin expression was observed in AAA tissue compared to control aorta (immunohistochemistry and western blot). In contrast, decreased circulating iron, transferrin, mean corpuscular haemoglobin concentration (MCHC) and haemoglobin concentration, along with circulating RBC count, were observed in AAA patients (aortic diameter >3 cm, n=114) compared to controls (aortic diameter <3 cm, n=88) (ELISA), whereas hepcidin concentrations were increased in AAA subjects (MS/MS assay). Moreover, iron, transferrin and haemoglobin levels were negatively, and hepcidin positively, correlated with aortic diameter in AAA patients. The association of low haemoglobin with AAA presence or aortic diameter was independent of specific risk factors. Moreover, MCHC negatively correlated with thrombus area in another cohort of AAA patients (aortic diameter 3–5 cm, n=357). We found that anaemia was significantly more prevalent in AAA patients (aortic diameter >5 cm, n=8,912) compared to those in patients with atherosclerotic aorto-iliac occlusive disease (n=17,737) [adjusted odds ratio=1.77 (95% confidence interval: 1.61;1.93)]. Finally, the mortality risk among AAA patients with anaemia was increased by almost 30% [adjusted hazard ratio: 1.29 (95% confidence interval: 1.16;1.44)] as compared to AAA subjects without anaemia. In conclusion, local iron retention and altered iron recycling associated to high hepcidin and low transferrin systemic concentrations could lead to reduced circulating haemoglobin levels in AAA patients. Low haemoglobin levels are independently associated to AAA presence and clinical outcome.

Association of ficolin-3 with abdominal aortic aneurysm presence and progression

Essentials Abdominal aortic aneurysm (AAA) is asymptomatic and its evolution unpredictable. To find novel potential biomarkers of AAA, microvesicles are an excellent source of biomarkers. Ficolin-3 is increased in microvesicles obtained from activated platelets and AAA tissue. Increased ficolin-3 plasma levels are associated with AAA presence and progression.

SUMMARY

Background Abdominal aortic aneurysm (AAA) patients are usually asymptomatic and AAA evolution is unpredictable. Ficolin-3, mainly synthesized by the liver, is a molecule of the lectin complement-activation pathway involved in AAA pathophysiology. Objectives To define extra-hepatic sources of ficolin-3 in AAA and investigate the role of ficolin-3 as a biomarker of the presence and progression of AAA. Methods Microvesicles (exosomes and microparticles) were isolated from culture-conditioned medium of ADP-activated platelets, as well as from AAA tissue-conditioned medium (thrombus and wall). Ficolin-3 levels were analyzed by western-blot, real-time PCR, immunohistochemistry and ELISA. Results Increased ficolin-3 levels were observed in microvesicles isolated from activated platelets. Similarly, microvesicles released from AAA tissue display increased ficolin-3 levels as compared with those from healthy tissue. Moreover, ficolin-3 mRNA levels in the AAA wall were greatly increased compared with healthy aortic walls. Immunohistochemistry of AAA tissue demonstrated increased ficolin-3, whereas little staining was present in healthy walls. Finally, increased ficolin-3 levels were observed in AAA patients' plasma (n = 478) compared with control plasma (n = 176), which persisted after adjustment for risk factors (adjusted odds ratio [OR], 5.29; 95% confidence interval [CI], 3.27, 8.57)]. Moreover, a positive association of ficolin-3 with aortic diameter (Rho, 0.25) and need for surgical repair was observed, also after adjustment for potential confounding factors (adjusted hazard ratio, 1.55; 95% CI, 1.11, 2.15). Conclusions In addition to its hepatic expression, ficolin-3 may be released into the extracellular medium via microvesicles, by both activated cells and pathological AAA tissue. Ficolin-3 plasma levels are associated with the presence and progression of AAA, suggesting its potential role as a biomarker of AAA.

Soluble TWEAK and Major Adverse Cardiovascular Events in Patients with CKD

BACKGROUND AND OBJECTIVES

Soluble TNF-like weak inducer of apoptosis (sTWEAK) is a proinflammatory cytokine belonging to the TNF superfamily. sTWEAK concentrations have been associated with the presence of CKD and cardiovascular disease (CVD). We hypothesized that sTWEAK levels may relate to a higher prevalence of atherosclerotic plaques, vascular calcification, and cardiovascular outcomes observed in patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A 4-year prospective, multicenter, longitudinal study was conducted in 1058 patients with CKD stages 3-5D (mean age =58±13 years old; 665 men) but without any history of CVD from the NEFRONA Study (a study design on the prevalence of surrogate markers of CVD). Ankle-brachial index and B-mode ultrasound were performed to detect the presence of carotid and/or femoral atherosclerotic plaques together with biochemical measurements and sTWEAK assessment. Patients were followed for cardiovascular outcomes (follow-up of 3.13±1.15 years).

RESULTS

Patients with more advanced CKD had lower sTWEAK levels. sTWEAK concentrations were independently and negatively associated with carotid intima-media thickness. sTWEAK levels were lower in patients with carotid atherosclerotic plaques but not in those with femoral plaques. After adjustment by confounders, the odds ratio (OR) for presenting carotid atherosclerotic plaques in patients in the lowest versus highest tertile of sTWEAK was 4.18 (95% confidence interval [95% CI], 2.89 to 6.08; P<0.001). Furthermore, sTWEAK levels were lower in patients with calcified carotid atherosclerotic plaques. The OR for presenting calcified carotid plaques was 1.77 (95% CI, 1.06 to 2.93; P=0.02) after multivariable adjustment. After the follow-up, 41 fatal and 68 nonfatal cardiovascular events occurred. In a Cox model, after controlling for potential confounding factors, patients in the lowest tertile of sTWEAK concentrations had a higher risk of fatal and nonfatal cardiovascular events (hazard ratio [HR], 2.40; 95% CI, 1.33 to 4.33; P=0.004) and cardiovascular mortality (HR, 2.67; 95% CI, 1.05 to 6.76; P=0.04).

CONCLUSIONS

Low sTWEAK levels were associated with the presence of carotid atherosclerotic plaques in patients with CKD. Additionally, lower sTWEAK levels were associated with a higher risk of cardiovascular morbidity and mortality.

Parathormone Levels Are Independently Associated with the Presence of Left Ventricular Hypertrophy in Patients with Coronary Artery Disease

BACKGROUND

Abnormalities of mineral metabolism and inflammation may affect the cardiovascular system. We have assessed the relationship of left ventricular hypertrophy (LVH) with inflammation and mineral metabolism.

METHODS

LVH was measured in 146 outpatients with stable coronary artery disease (SCAD) using echocardiography. Calcidiol (a vitamin D metabolite), parathyroid hormone (PTH), fibroblast growth factor-23, high-sensitivity C-reactive protein, MCP-1 (monocyte chemoattractant protein-1), galectin-3, NGAL (neutrophil gelatinase-associated lipocalin), and sTWEAK (soluble TNF-related weak inducer of apoptosis) plasma levels were studied.

RESULTS

LVH, defined as septal thickness ≥11 mm, was present in 19.9% of cases. These patients were older [75.0 (61.0-81.0) vs 64.0 (51.0-76.0) years; p=0.002], had higher prevalence of left ventricular ejection fraction (LVEF)>40%, and had higher PTH [84.7 (59.6-104.7) vs 63.2 (49.2-85.2) pg/ml; p=0.007], galectin-3 [9.6 (8.0-11.1) vs 8.3 (6.9-9.9) ng/ml; p=0.037], and NGAL (208.5±87.6 vs 173.9±73.4 ng/ml; p=0.031) plasma levels than those without LVH. Glomerular filtration rate was lower in patients with LVH than in those without it (65.1±20.0 vs 74.7±19.9 mL/min/1.73 m2; p=0.021). There were no significant differences in hypertension (79.3 vs 68.4%; p=0.363) or sex between both groups. Variables showing differences based on univariate analysis and hypertension were entered into a logistic regression analysis. Only age [odds ratio (OR) =1.052 (1.011-1.096); p=0.013], PTH plasma levels [OR=1.017 (1.003-1.031); p=0.021], and LVEF>40% [OR=7.595 (1.463-39.429); p=0.016] were independent predictors of LVH.

CONCLUSIONS

In patients with SCAD, elevated PTH levels are independently associated with the presence of LVH. Further studies are needed to elucidate the role of PTH in the development of myocardial hypertrophy.

Tumor necrosis factor-like weak inducer of apoptosis or Fn14 deficiency reduce elastase perfusion-induced aortic abdominal aneurysm in mice

Background

Abdominal aortic aneurysm (AAA) involves leukocyte recruitment, inflammatory cytokine production, vascular cell apoptosis, neovascularization, and vascular remodeling, all of which contribute to aortic dilatation. Tumor necrosis factor‐like weak inducer of apoptosis (TWEAK) is a cytokine implicated in proinflammatory responses, angiogenesis, and matrix degradation but its role in AAA formation is currently unknown.

Methods and Results

Experimental AAA with aortic elastase perfusion in mice was induced in wild‐type (WT), TWEAK deficient (TWEAK KO), or Fn14‐deficient (Fn14 KO) mice. TWEAK or Fn14 KO deficiency reduced aortic expansion, lesion macrophages, CD3⁺ T cells, neutrophils, CD31⁺ microvessels, CCL2 and CCL5 chemokines expression, and MMP activity after 14 days postperfusion. TWEAK and Fn14 KO mice also showed a reduced loss of medial vascular smooth muscle cells (VSMC) that was related to a reduced number of apoptotic cells in these animals compared with WT mice. Aortas from WT animals present a higher disruption of the elastic layer and MMP activity than those from TWEAK or Fn14 KO mice, indicating a diminished vascular remodeling in KO animals. In vitro experiments unveiled that TWEAK induces CCL5 secretion and MMP‐9 activation in both VSMC and bone marrow‐derived macrophages, and decrease VSMC viability, effects dependent on Fn14.

Conclusions

TWEAK/Fn14 axis participates in AAA formation by promoting lesion inflammatory cell accumulation, angiogenesis, matrix‐degrading protease expression, and vascular remodeling. Blocking TWEAK/Fn14 interaction could be a new target for the treatment of AAA.

[Atorvastatin inhibits the atherosclerotic lesion induced by tumor necrosis factor-like weak inducer of apoptosis in apolipoprotein E deficient mice]

AIM

Interaction of tumor necrosis factor-like weak inducer of apoptosis (TWEAK) with its receptor Fn14 accelerates atherosclerotic plaque development in ApoE deficient mice (ApoE KO). In this work, an analysis has been made on the effect of an HMG-CoA reductase inhibitor, atorvastatin, on atherosclerotic plaque development accelerated by TWEAK in ApoE KO mice.

MATERIALS AND METHODS

Eight week-old ApoE KO mice were fed with a high cholesterol diet for 4 weeks. The animals were then randomized into 3 groups: mice injected i.p. with saline, recombinant TWEAK (10 μg/kg/twice a week), or recombinant TWEAK plus atorvastatin (1 mg/kg/day) for 4 weeks. The lesion size, cellular composition, lipid and collagen content were analyzed, as well as inflammatory response in atherosclerotic plaques present in aortic root of mice.

RESULTS

TWEAK treated mice showed an increase in atherosclerotic plaque size, as well as in collagen/lipid ratio compared with control mice. In addition, macrophage content, MCP-1 and RANTES expression, and NF-κB activation were augmented in atherosclerotic plaques present in aortic root of TWEAK treated mice compared with control mice. Treatment with atorvastatin prevented all these changes induced by TWEAK in atherosclerotic lesions. Atorvastatin treatment also decreased Fn14 expression in the atherosclerotic plaques of ApoE KO mice.

CONCLUSIONS

Atorvastatin prevents the pro-atherogenic effects induced by TWEAK in ApoE KO mice, which could be related to the inhibition of Fn14 expression. The results of this study provide new information on the beneficial effects of statin treatment in cardiovascular diseases.

Reduced sTWEAK and increased sCD163 levels in HIV-infected patients: modulation by antiretroviral treatment, HIV replication and HCV co-infection

Background

Patients infected with the human immunodeficiency virus (HIV) have an increased risk of cardiovascular disease due to increased inflammation and persistent immune activation. CD163 is a macrophage scavenger receptor that is involved in monocyte-macrophage activation in HIV-infected patients. CD163 interacts with TWEAK, a member of the TNF superfamily. Circulating levels of sTWEAK and sCD163 have been previously associated with cardiovascular disease, but no previous studies have fully analyzed their association with HIV.

Objective

The aim of this study was to analyze circulating levels of sTWEAK and sCD163 as well as other known markers of inflammation (hsCRP, IL-6 and sTNFRII) and endothelial dysfunction (sVCAM-1 and ADMA) in 26 patients with HIV before and after 48 weeks of antiretroviral treatment (ART) and 23 healthy subjects.

Results

Patients with HIV had reduced sTWEAK levels and increased sCD163, sVCAM-1, ADMA, hsCRP, IL-6 and sTNFRII plasma concentrations, as well as increased sCD163/sTWEAK ratio, compared with healthy subjects. Antiretroviral treatment significantly reduced the concentrations of sCD163, sVCAM-1, hsCRP and sTNFRII, although they remained elevated when compared with healthy subjects. Antiretroviral treatment had no effect on the concentrations of ADMA and sTWEAK, biomarkers associated with endothelial function. The use of protease inhibitors as part of antiretroviral therapy and the presence of HCV-HIV co-infection and/or active HIV replication attenuated the ART-mediated decrease in sCD163 plasma concentrations.

Conclusion

HIV-infected patients showed a proatherogenic profile characterized by increased inflammatory, immune-activation and endothelial-dysfunction biomarkers that partially improved after ART. HCV-HIV co-infection and/or active HIV replication enhanced immune activation despite ART.

Genetic deletion or TWEAK blocking antibody administration reduce atherosclerosis and enhance plaque stability in mice

Clinical complications associated with atherosclerotic plaques arise from luminal obstruction due to plaque growth or destabilization leading to rupture. Tumour necrosis factor ligand superfamily member 12 (TNFSF12) also known as TNF-related weak inducer of apoptosis (TWEAK) is a proinflammatory cytokine that participates in atherosclerotic plaque development, but its role in plaque stability remains unclear. Using two different approaches, genetic deletion of TNFSF12 and treatment with a TWEAK blocking mAb in atherosclerosis-prone mice, we have analysed the effect of TWEAK inhibition on atherosclerotic plaques progression and stability. Mice lacking both TNFSF12 and Apolipoprotein E (TNFSF12^−/−ApoE^−/−) exhibited a diminished atherosclerotic burden and lesion size in their aorta. Advanced atherosclerotic plaques of TNFSF12^−/−ApoE^−/− or anti-TWEAK treated mice exhibited an increase collagen/lipid and vascular smooth muscle cell/macrophage ratios compared with TNFSF12^+/+ApoE^−/− control mice, reflecting a more stable plaque phenotype. These changes are related with two different mechanisms, reduction of the inflammatory response (chemokines expression and secretion and nuclear factor kappa B activation) and decrease of metalloproteinase activity in atherosclerotic plaques of TNFSF12^−/−ApoE^−/−. A similar phenotype was observed with anti-TWEAK mAb treatment in TNFSF12^+/+ApoE^−/− mice. Brachiocephalic arteries were also examined since they exhibit additional features akin to human atherosclerotic plaques associated with instability and rupture. Features of greater plaque stability including augmented collagen/lipid ratio, reduced macrophage content, and less presence of lateral xanthomas, buried caps, medial erosion, intraplaque haemorrhage and calcium content were present in TNFSF12^−/−ApoE^−/− or anti-TWEAK treatment in TNFSF12^+/+ApoE^−/− mice. Overall, our data indicate that anti-TWEAK treatment has the capacity to diminish proinflamatory response associated with atherosclerotic plaque progression and to alter plaque morphology towards a stable phenotype.

TWEAK/Fn14 Axis: A Promising Target for the Treatment of Cardiovascular Diseases

Cardiovascular diseases (CVD) are the first cause of mortality in Western countries. CVD include several pathologies such as coronary heart disease, stroke or cerebrovascular accident, congestive heart failure, peripheral arterial disease, and aortic aneurysm, among others. Interaction between members of the tumor necrosis factor (TNF) superfamily and their receptors elicits several biological actions that could participate in CVD. TNF-like weak inducer of apoptosis (TWEAK) and its functional receptor and fibroblast growth factor-inducible molecule 14 (Fn14) are two proteins belonging to the TNF superfamily that activate NF-κB by both canonical and non-canonical pathways and regulate several cell functions such as proliferation, migration, differentiation, cell death, inflammation, and angiogenesis. TWEAK/Fn14 axis plays a beneficial role in tissue repair after acute injury. However, persistent TWEAK/Fn14 activation mediated by blocking experiments or overexpression experiments in animal models has shown an important role of this axis in the pathological remodeling underlying CVD. In this review, we summarize the role of TWEAK/Fn14 pathway in the development of CVD, focusing on atherosclerosis and stroke and the molecular mechanisms by which TWEAK/Fn14 interaction participates in these pathologies. We also review the role of the soluble form of TWEAK as a biomarker for the diagnosis and prognosis of CVD. Finally, we highlight the results obtained with other members of the TNF superfamily that also activate canonical and non-canonical NF-κB pathway.

Soluble TWEAK plasma levels increase after renal transplantation and associate with the improvement of endothelial function

BACKGROUND

Soluble TWEAK (sTWEAK) and asymmetric dimethyl arginine (ADMA) concentrations have been associated with endothelial function in patients with chronic kidney disease (CKD). We tested the hypothesis that the improvement in endothelial function observed after renal transplantation is directly linked to the normalization of both sTWEAK and ADMA.

MATERIALS AND METHODS

One hundred and seventy-five kidney transplant recipients (71% men; 31·6 ± 9·4 years) were studied immediately before and on the 180th day post-transplantation. At each visit, blood samples were taken to assess circulating levels of sTWEAK and ADMA. Brachial artery endothelium-dependent vasodilatation (FMD) assessments were also performed.

RESULTS

Renal transplantation was followed by an improvement in FMD. This improvement was paralleled by an increase in sTWEAK and a reduction in ADMA after transplantation (P < 0·001 for all). Cross-sectionally, both molecules associated with FMD before as well as after transplantation (P < 0·001 for all). Longitudinally, the changes observed in sTWEAK (β = 0·26, P < 0·001) and ADMA (β = -0·44, P < 0·001) levels were independently associated with the improvement of FMD (r(2)  = 0·30).

CONCLUSIONS

Renal transplantation is followed by an improvement of FMD that is independently associated with the normalization of both sTWEAK and ADMA concentrations. We identify two surrogate biomarkers of endothelial function with potential as therapeutic targets.

HMGB1 Expression and Secretion Are Increased Via TWEAK–Fn14 Interaction in Atherosclerotic Plaques and Cultured Monocytes

Objective—

High-mobility group box 1 (HMGB1), a DNA-binding cytokine expressed mainly by macrophages, contributes to lesion progression and chronic inflammation within atherosclerotic plaque. It has been suggested that different cytokines could regulate HMGB1 expression in monocytes. We have analyzed the effect of tumor necrosis factor–like weak inducer of apoptosis (TWEAK) on HMGB1 expression both in vivo and in vitro.

Methods and Results—

Expression of TWEAK and its receptor fibroblast growth factor–inducible 14 (Fn14) was positively correlated with HMGB1 in human carotid atherosclerotic plaques. TWEAK increased HMGB1 mRNA expression and protein secretion in human acute monocytic leukemia cell line cultured monocytes. TWEAK-mediated HMGB1 increase was only observed in M1 macrophages but not in M2 ones. These effects were reversed using blocking anti-Fn14 antibody or nuclear factor-kappa B and phosphotidylinositol-3 kinase inhibitors. TWEAK also increased monocyte chemoattractant protein-1 secretion in human acute monocytic leukemia cell line cells, an effect blocked with an HMGB1 small interfering RNA. Systemic TWEAK injection in ApoE −/− mice increased HMGB1 protein expression in the aortic root and mRNA expression in total aorta of ApoE −/− mice. Conversely, TWEAK-blocking antibodies diminished HMGB1 protein and mRNA expression compared with IgG-treated mice.

Conclusion—

Our results indicate that TWEAK can regulate expression and secretion of HMGB1 in monocytes/macrophages, participating in the inflammatory response associated with atherosclerotic plaque development.

Vascular proteomics and the discovery process of clinical biomarkers: The case of TWEAK

In the last years, big efforts are devoted to the search of novel biomarkers. Proteomic approaches in healthy and pathological samples may help us to discern differential protein expression patterns. These identified proteins include potential culprits in pathological pathways and/or clinical biomarkers to identify individuals at risk. However, extensively validation must be carried out before their implementation into the clinical practice. Biomarkers need to discriminate between health and disease, detect preclinical disease stages, have impact on survival prediction, and add predictive value beyond traditional risk factors and global risk algorithms. Now, we summarize the data of soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK), a new cardiovascular biomarker identified by proteomic analysis. Decreased sTWEAK concentrations have been shown in patients with carotid atherosclerosis, coronary artery disease, congestive heart failure, peripheral artery disease, or chronic kidney disease (CKD). sTWEAK predicted adverse outcomes in patients with heart failure, myocardial infarction, and CKD. Finally, different drug regimens were able to modify sTWEAK plasma levels in patients with CKD. Although sTWEAK seems so far to fulfill the requisites in the development of a new biomarker, more large-scale studies are warranted to consolidate its usefulness.

TWEAK-Fn14 interaction enhances plasminogen activator inhibitor 1 and tissue factor expression in atherosclerotic plaques and in cultured vascular smooth muscle cells

AIMS

atherosclerotic plaque development can conclude with a thrombotic acute event triggered by plaque rupture/erosion. Tumour necrosis factor-like weak inducer of apoptosis (TWEAK) is a member of the tumour necrosis factor superfamily that, through its receptor, fibroblast growth factor-inducible 14 (Fn14), participates in vascular remodelling, increasing vascular inflammatory responses and atherosclerotic lesion size in ApoE knockout mice. However, the role of the TWEAK-Fn14 axis in thrombosis has not been previously investigated.

METHODS AND RESULTS

we have examined whether TWEAK regulates expression of prothrombotic factors such as tissue factor (TF) and plasminogen activator inhibitor 1 (PAI-1) in atherosclerotic plaques as well as in human aortic vascular smooth muscle cells (hASMCs) in culture. Expression of TF and PAI-1 was colocalized and positively correlated with Fn14 in human carotid atherosclerotic plaques. In vitro, TWEAK increased TF and PAI-1 mRNA, protein expression and activity in hASMCs. All these effects were reversed using blocking anti-TWEAK monoclonal antibody, anti-Fn14 antibody or Fn14 small interfering RNA, indicating that TWEAK increased the prothrombotic state through its receptor, Fn14. Finally, ApoE(-/-) mice were fed a hyperlipidaemic diet for 10 weeks, then randomized and treated with saline (controls), TWEAK (10 microg/kg/day), anti-TWEAK neutralizing monoclonal antibody (1000 µg/kg/day), or non-specific immunoglobulin G (1000 microg/kg/day) daily for 9 days. Systemic TWEAK injection increased TF and PAI-1 protein expression in the aortic root of ApoE(-/-) mice. Conversely, TWEAK blocking antibodies diminished both TF and PAI-1 protein expression compared with non-specific immunoglobulin G-treated mice.

CONCLUSIONS

our results indicate that the TWEAK-Fn14 axis can regulate activation of TF and PAI-1 expression in vascular cells. TWEAK-Fn14 may be a therapeutic target in the prothrombotic complications associated with atherosclerosis.

Increased levels of thioredoxin in patients with abdominal aortic aneurysms (AAAs). A potential link of oxidative stress with AAA evolution

OBJECTIVE

Oxidative stress is a main mechanism involved in vascular pathologies. Increased thioredoxin (TRX) levels have been observed in several oxidative stress-associated cardiovascular diseases. We aim to test the potential role of TRX as a biomarker of oxidative stress in abdominal aortic aneurysm (AAA).

METHODS

TRX levels were analysed in both AAA intraluminal thrombus (ILT) tissue and in tissue-conditioned media by immunohistochemistry, Western blot and ELISA. Moreover, serum TRX levels were assessed in AAA Caucasian patients by ELISA.

RESULTS

TRX was mainly localized in the luminal part of ILT in AAA. Compared with the abluminal layer, TRX release was increased in the luminal layer of the ILT of AAA (31+/-9 ng/ml vs. 9+/-3 ng/ml, p<0.05). The interest of this approach is that we can identify proteins potentially released into the blood compartment, which could serve as biomarkers of the pathology. In a training population, serum TRX levels were significantly increased in patients with AAA relative to healthy subjects (50+/-6 ng/ml vs. 26+/-3 ng/ml, p<0.05). These results were validated in a second independent group of patients. Moreover, a positive correlation between TRX and AAA size (rho=0.5, p<0.001) was observed. Finally, in AAA samples with follow-up, TRX was positively associated to aneurismal growth rate (rho=0.25, p=0.027).

CONCLUSIONS

TRX release is increased in the luminal part of AAA and TRX serum levels are increased in AAA patients compared with healthy subjects. TRX levels correlates with AAA size and expansion, suggesting its potential role as a biomarker of AAA evolution.

Peripheral artery disease is associated with a high CD163/TWEAK plasma ratio

OBJECTIVE

In addition to its role in the clearance of haptoglobin-hemoglobin (Hp-Hb) complexes, CD163 is a macrophage scavenger receptor for tumor necrosis factor-like weak inducer of apoptosis (TWEAK). We recently reported that the CD163/TWEAK plasma ratio could be a potential biomarker of atherothrombosis in asymptomatic subjects. In this study, we assessed soluble TWEAK (sTWEAK) and soluble CD163 (sCD163) plasma levels in white males with peripheral artery disease (PAD) and in atherothrombotic femoral plaques to evaluate their relationship with disease. We also analyzed whether Hp-Hb complexes could compete for CD163-mediated TWEAK uptake.

METHODS AND RESULTS

Patients with PAD (n=155) showed a trend toward lower sTWEAK (median [interquartile range]: 134 [110-204] versus 147 [119-205] pg/mL; P=0.067) and higher sCD163 (median [interquartile range]: 367 [269-506] versus 288 [234-369] ng/mL; P<0.001) plasma concentrations than age-matched controls (n=251). sCD163 and sTWEAK plasma levels were negatively correlated in both patients and controls. After stratification according to the severity of disease, sCD163/sTWEAK ratio was significantly increased in patients with more severe disease relative to the other groups (P=0.049). Analysis of conditioned medium obtained from cultured human atherothrombotic femoral plaque samples (n=36) and healthy aortas (n=14) revealed that high amounts of sCD163 were released by the atherothrombotic tissue, whereas sTWEAK presented the opposite trend (P<0.05). Finally, we report a potential association between CD163 shedding and oxidative stress.

CONCLUSIONS

Our results suggest that the sCD163/sTWEAK plasma ratio may be associated with atherothrombosis burden in PAD. We hypothesize that an imbalance between TWEAK and CD163 could reflect the progression of atherothrombosis.

TWEAK activates the non-canonical NFkappaB pathway in murine renal tubular cells: modulation of CCL21

TWEAK is a member of the TNF superfamily of cytokines that contribute to kidney tubulointerstitial injury. It has previously been reported that TWEAK induces transient nuclear translocation of RelA and expression of RelA-dependent cytokines in renal tubular cells. Additionally, TWEAK induced long-lasting NFκB activation suggestive of engagement of the non-canonical NFκB pathway. We now explore TWEAK-induced activation of NFκB2 and RelB, as well as expression of CCL21, a T-cell chemotactic factor, in cultured murine tubular epithelial cells and in healthy kidneys in vivo. In cultured tubular cells, TWEAK and TNFα activated different DNA-binding NFκB complexes. TWEAK-induced sustained NFκB activation was associated with NFκB2 p100 processing to p52 via proteasome and nuclear translocation and DNA-binding of p52 and RelB. TWEAK, but not TNFα used as control), induced a delayed increase in CCL21a mRNA (3.5±1.22-fold over control) and CCL21 protein (2.5±0.8-fold over control), which was prevented by inhibition of the proteasome, or siRNA targeting of NIK or RelB, but not by RelA inhibition with parthenolide. A second NFκB2-dependent chemokine, CCL19, was upregulates by TWEAK, but not by TNFα. However, both cytokines promoted chemokine RANTES expression (3-fold mRNA at 24 h). In vivo, TWEAK induced nuclear NFκB2 and RelB translocation and CCL21a mRNA (1.5±0.3-fold over control) and CCL21 protein (1.6±0.5-fold over control) expression in normal kidney. Increased tubular nuclear RelB and tubular CCL21 expression in acute kidney injury were decreased by neutralization (2±0.9 vs 1.3±0.6-fold over healthy control) or deficiency of TWEAK (2±0.9 vs 0.8±0.6-fold over healthy control). Moreover, anti-TWEAK treatment prevented the recruitment of T cells to the kidney in this model (4.1±1.4 vs 1.8±1-fold over healthy control). Our results thus identify TWEAK as a regulator of non-canonical NFκB activation and CCL21 expression in tubular cells thus promoting lymphocyte recruitment to the kidney during acute injury.

Biomarkers in cardiovascular medicine

Cardiovascular disease is the principal cause of death in developed countries. The underlying pathological process is arterial wall thickening due to the formation of atherosclerotic plaque, which is frequently complicated by thrombus, thereby giving rise to the possibility of acute coronary syndrome or stroke. One of the major challenges in cardiovascular medicine is to find a way of predicting the risk that an individual will suffer an acute thrombotic event. During the last few decades, there has been considerable interest in finding diagnostic and prognostic biomarkers that can be detected in blood. Of these, C-reactive protein is the best known. Others, such as the soluble CD40 ligand, can be used to predict cardiovascular events. However, to date, no biomarker has been generally accepted for use in clinical practice. At present, there are a number of high-performance techniques, such as proteomics, that have the ability to detect multiple potential biomarkers. In the near future, these approaches may lead to the discovery of new biomarkers that, when used with imaging techniques, could help improve our ability to predict the occurrence of acute vascular events.

The CD163-expressing macrophages recognize and internalize TWEAK: potential consequences in atherosclerosis

BACKGROUND

CD163 is a new potential scavenger receptor of Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) which elicits diverse biologic actions involved in atherosclerosis. We have analyzed the importance of TWEAK-CD163 interaction in atherosclerosis.

METHODS

TWEAK and CD163 interaction was studied in cultured human macrophages. Moreover, TWEAK and CD163 expression was analyzed in carotid atherosclerotic plaques (immunohistochemistry) and plasma (ELISA). We have also assessed their potential association with intima/media thickness (IMT) in asymptomatic subjects.

RESULTS

In vitro studies revealed that CD163-expressing macrophages can bind and internalize TWEAK protein exogenously added from supernatants. Accordingly, we observed an inverse correlation between the expression of CD163 and TWEAK (r=-0.51; p=0.008) in the shoulder region of atherosclerotic plaques obtained from 25 patients undergoing carotid endarterectomy. The same trend was observed when we analyzed the plasma concentration of both proteins in 90 subjects free from clinical cardiovascular disease (r=-0.25; p=0.016) in which carotid ultrasonography was performed to determine IMT. In these subjects, we found a positive correlation between sCD163 and IMT (r=0.36; p<0.001) and between sCD163-sTWEAK ratio and IMT (r=0.51; p<0.001). This association remained significant after adjusting for traditional cardiovascular risk factors and inflammatory markers explaining 39% (sCD163) or 48% (sCD163-sTWEAK ratio) of IMT variance.

CONCLUSIONS

Our results suggest that TWEAK-CD163 interaction takes place in vivo, probably decreasing TWEAK plasma concentration. Furthermore, we have observed that CD163-TWEAK plasma ratio is a potential biomarker of clinical and subclinical atherosclerosis.

Tweak induces proliferation in renal tubular epithelium: a role in uninephrectomy induced renal hyperplasia

The tumour necrosis factor (TNF) family member TWEAK activates the Fn14 receptor and has pro-apoptotic, proliferative and pro-inflammatory actions that depend on the cell type and the microenvironment. We explored the proliferative actions of TWEAK on cultured tubular cells and in vivo on renal tubules. Additionally, we studied the role of TWEAK in compensatory proliferation following unilateral nephrectomy and in an inflammatory model of acute kidney injury (AKI) induced by a folic acid overdose. TWEAK increased the proliferation, cell number and cyclin D1 expression of cultured tubular cells, in vitro. Exposure to serum increased TWEAK and Fn14 expression and the proliferative response to TWEAK. TWEAK activated the mitogen-activated protein kinases ERK and p38, the phosphatidyl-inositol 3-kinase (PI3K)/Akt pathway and NF-κB. TWEAK-induced proliferation was prevented by inhibitors of these protein kinases and by the NF-κB inhibitor parthenolide. TWEAK-induced tubular cell proliferation as assessed by PCNA and cyclin D1 expression in the kidneys of adult healthy mice in vivo. By contrast, TWEAK knock-out mice displayed lower tubular cell proliferation in the remnant kidney following unilateral nephrectomy, a non-inflammatory model. This is consistent with TWEAK-induced proliferation on cultured tubular cells in the absence of inflammatory cytokines. Consistent with our previously published data, in the presence of inflammatory cytokines TWEAK promoted apoptosis, not proliferation, of cultured tubular cells. In this regard, TWEAK knock-out mice with AKI displayed less tubular apoptosis and proliferation, as well as improved renal function. In conclusion, TWEAK actions in tubular cells are context dependent. In a non-inflammatory milieu TWEAK induces proliferation of tubular epithelium. This may be relevant for compensatory renal hyperplasia following nephrectomy.

Plasma fingerprinting with GC-MS in acute coronary syndrome

New biomarkers of cardiovascular disease are needed to augment the information obtained from traditional indicators and to illuminate disease mechanisms. One of the approaches used in metabolomics/metabonomics for that purpose is metabolic fingerprinting aiming to profile large numbers of chemically diverse metabolites in an essentially nonselective way. In this study, gas chromatography-mass spectrometry was employed to evaluate the major metabolic changes in low molecular weight plasma metabolites of patients with acute coronary syndrome (n = 9) and with stable atherosclerosis (n = 10) vs healthy subjects without significant differences in age and sex (n = 10). Reproducible differences between cases and controls were obtained with pattern recognition techniques, and metabolites accounting for higher weight in the classification have been identified through their mass spectra. On this basis, it seems inherently plausible that even a simple metabolite profile might be able to offer improved clinical diagnosis and prognosis, but in addition, specific markers are being identified.

Additive effects of soluble TWEAK and inflammation on mortality in hemodialysis patients

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) is characterized by an exceptionally high mortality rate, primarily due to cardiovascular disease. Reduced soluble TNF-like weak inducer of apoptosis (sTWEAK) plasma levels have been reported both in patients with subclinical atherosclerosis and CKD.

DESIGN, PARTICIPANTS, & MEASUREMENTS

A cross-sectional study was conducted in 218 prevalent patients (121 men; 63 +/- 14 yr) undergoing hemodialysis (HD). sTWEAK levels in relation with the patients' outcome were studied.

RESULTS

sTWEAK plasma levels were 208 [(165 to 272) pg/ml, median interquartile range], significantly lower than healthy controls (P < 0.0001). sTWEAK was negatively associated with inflammatory markers, such as C-reactive protein and IL-6. Overall mortality was assessed after an average follow-up of 31 mo, during which 81 patients died. After controlling for potential confounding variables, patients in the upper tertile of sTWEAK plasma levels had an increased risk of cardiovascular and all-cause mortality. A significant interaction effect between sTWEAK and IL-6 levels was found [synergy index: 2.19 (0.80, 5.93)]. Thus, the association of sTWEAK with mortality was strongest in patients with inflammation (defined as IL-6 > 7.0 pg/ml), in whom high sTWEAK strongly predicted cardiovascular and all-cause mortality. These results were confirmed in a second cohort of HD patients.

CONCLUSIONS

The concurrent presence of elevated sTWEAK plasma concentrations and an inflammatory environment have additive effects on mortality in HD patients. Further studies on the potential different role of sTWEAK in health and disease are warranted.

Olive oil and walnut breakfasts reduce the postprandial inflammatory response in mononuclear cells compared with a butter breakfast in healthy men

BACKGROUND

Inflammation is crucial in all stages of atherosclerosis, and few studies have investigated the effect of dietary fat on markers of inflammation related to this disease during the postprandial period.

OBJECTIVE

To evaluate the chronic effects of dietary fat on the postprandial expression of proinflammatory genes in peripheral blood mononuclear cells (PBMCs) in healthy subjects.

DESIGN

20 healthy men followed three different diets for 4 weeks each, according to a randomized crossover design: Western diet: 15% protein, 47% carbohydrates (CHO), 38% fat (22% saturated fatty acid (SFA)); Mediterranean diet: 15% protein, 47% CHO, 38% fat (24% monounsaturated fatty acid (MUFA)); CHO-rich and n-3 diet: 15% protein, 55% CHO, <30% fat (8% polyunsaturated fatty acid (PUFA)). After 12-h fast, volunteers were given a breakfast with a fat composition similar to that consumed in each of the diets-butter breakfast: 35% SFA; olive oil breakfast: 36% MUFA; walnut breakfast: 16% PUFA, 4% alpha-linolenic acid (LNA).

RESULTS

The butter breakfast induced a higher increase in tumor necrosis factor (TNF)-alpha messenger RNA (mRNA) expression than the olive oil or walnut breakfasts (P=0.014) in PBMCs. Moreover, we found a higher postprandial response in the mRNA of interleukin (IL)-6 with the intake of butter and olive oil breakfasts than with the walnut breakfast (P=0.025) in these cells. However, the effects of the three fatty breakfasts on the plasma concentrations of these proinflammatory parameters showed no significant differences (P=N.S.).

CONCLUSION

Consumption of a butter-enriched meal elicits greater postprandial expression of proinflammatory cytokine mRNA in PBMCs, compared to the olive oil and walnut breakfasts.

Atorvastatin modulates the profile of proteins released by human atherosclerotic plaques

The mechanisms by which hydroxymethylglutaryl CoenzymeA reductase inhibitors (statins) reduce atherosclerotic cardiovascular morbidity and mortality remain poorly understood. Statins have been shown to modulate the levels of different inflammatory proteins both in carotid atherosclerotic plaques and in the blood of patients with atherosclerosis. In this work, we hypothesize that statins could also modulate the levels of the proteins secreted by cultured atherosclerotic plaques. Thus, the secretomes obtained from complicated atherosclerotic plaques incubated in the presence/absence of atorvastatin (10 micromol/l, 24 h) were analysed and compared by two-dimensional electrophoresis, considering the fibrous adjacent areas as controls. In total, 54 proteins (83 protein isoforms) were identified by Mass Spectrometry (MS): 24 proteins were increased and 20 proteins decreased in atheroma plaque supernatants compared to controls. Some of these proteins, like Cathepsin D, could play a significant role in plaque instability, becoming a potential target for therapeutical treatment. Interestingly, 66% of the proteins differentially released by atherosclerotic plaques reverted to control values after administration of atorvastatin, among them, Cathepsin D. Moreover, plaques obtained from patients who received atorvastatin treatment prior to carotid endarterectomy showed decreased Cathepsin D expression relative to plaques from non-treated patients. In conclusion, this proteomic approach has shown that statins are able to modulate the secretome of atherosclerotic plaques, and new therapeutical targets for statins have been characterised.

Identification of soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK) as a possible biomarker of subclinical atherosclerosis

OBJECTIVES

Assessment of vascular risk in asymptomatic patients and the response to medical therapy is a major challenge for prevention of cardiovascular events. Our aim was to identify proteins differentially released by healthy versus atherosclerotic arterial walls, which could be found in plasma and serve as markers of atherosclerosis.

METHODS AND RESULTS

We have analyzed supernatants obtained from cultured human carotid plaques and healthy arteries by surface-enhanced laser-desorption/ionization time-of-flight mass spectrometry ProteinChip System. Surface-enhanced laser-desorption/ionization analysis unveiled an 18.4-kDa peak released in lower amount by carotid plaques than normal endarteries. This protein was identified as soluble tumor necrosis factor-like weak inducer of apoptosis (sTWEAK). To confirm that sTWEAK was the protein of interest, Western blot and enzyme-linked immunosorbent assay were performed. Both techniques confirmed that sTWEAK levels were decreased in carotid plaque supernatants. Subsequent measurement of sTWEAK in plasma showed a reduced concentration in subjects with carotid stenosis (N=30) compared with healthy subjects matched by sex and age (N=28) (P<0.001). Furthermore, in a test population of 106 asymptomatic subjects, we showed that sTWEAK concentrations negatively correlated with the carotid intima-media thickness (r=-0.4; P<0.001), an index of subclinical atherosclerosis.

CONCLUSIONS

These results suggest that sTWEAK could be a potential biomarker of atherosclerosis.

Trail and vascular injury

Cardiovascular diseases are the leading cause of mortality in the Western world. The underlying pathological process is a thickening of the arterial wall due to the formation of atheromatous plaques which contain a lipid core covered by a fibrous cap. The main mechanisms involved in atherogenesis are: lipoprotein retention, endothelial cell activation, vascular smooth muscle cell proliferation, macrophage infiltration, proteolytic injury, neovascularization and apoptosis. Different members of the tumor necrosis factor family (TNF) of proteins have been detected in human atherosclerotic plaques, among these are TNF-related apoptosis-inducing ligand (TRAIL) and its receptors (TRAIL-Rs and osteoprotegerin, OPG). In this review, the involvement of TRAIL and its receptors in the mechanisms underlying atherothrombosis is reviewed. In this respect, there are still some controversial data on the effects of TRAIL on inflammation and apoptosis of vascular cells. However, recent in vivo studies have suggested a potential proinflammatory and proapoptotic role of TRAIL in vascular injury. In addition, soluble forms of the TNF-superfamily can be released extracellularly and have been detected in human plasma. For this reason, we different studies evaluating the potential use of TRAIL and OPG plasma levels as markers of vascular injury are discussed.