Emerging inflammatory markers for assessing coronary heart disease risk

Down-regulation and Clinical Implication of Galectin-9 Levels in Patients with Acute Coronary Syndrome and Chronic Kidney Disease

In various autoimmune diseases, Galecin-9 (Gal-9) has been shown to regulate the T-cell balance by decreasing Th1 and Th17, while increasing the number of regulatory T cells (Tregs). However, the role of Gal-9 in the patients with acute coronary syndrome (ACS) and chronic kidney disease (CKD) remains unclear. This study aims to measure the Gal-9 levels in serum and peripheral blood mononuclear cells (PBMCs) in patients with ACS plus CKD and examine their clinical implication. The serum levels of Gal-9 were determined by enzyme-linked immunosorbent assay (ELISA), the expression levels of Gal-9, Tim-3, and Foxp3 mRNA in PBMCs were detected by real-time reverse transcription-polymerase chain reaction (RT-PCR), and the expression of Gal-9 on the surface of PBMCs and in PBMCs was analyzed by flow cytometry. Furthermore, the correlation of serum Gal-9 levels with anthropometric and biochemical variables in patients with ACS plus CKD was analyzed. The lowest levels of Gal-9 in serum and PBMCs were found in the only ACS group, followed by the ACS+CKD group, and the normal coronary artery (NCA) group, respectively. Serum Gal-9 levels were increased along with the progression of glomerular filtration rate (GFR) categories of G1 to G4. Additionally, serum Gal-9 levels were negatively correlated with high-sensitivity C-reactive protein (hs-CRP), estimated GFR (eGFR), and lipoprotein(a), but positively with creatinine, age, osmotic pressure, and blood urea nitrogen (BUN). Notably, serum Gal-9 was independently associated with hs-CRP, osmotic pressure, and lipoprotein(a). Furthermore, serum Gal-9 levels were elevated in patients with type 2 diabetes (T2DM) and impaired glucose tolerance (IGT) in ACS group. It was suggested that the levels of Gal-9 in serum and PBMCs were decreased in patients with simple ACS and those with ACS plus CKD, and hs-CRP, eGFR, osmotic pressure and T2DM may have an influence on serum Gal-9 levels.

Serum Galectin-9 Levels Are Associated with Coronary Artery Disease in Chinese Individuals

Background. Recently, several studies suggest that galectin-9 (Gal-9) might play a pivotal role in the pathogenesis of autoimmune diseases. However, the exact role of Gal-9 in atherosclerosis remains to be elucidated. Methods. Serum Gal-9, high-sensitivity C-reactive protein (hs-CRP), interferon- (IFN-) γ, interleukin- (IL-) 4, IL-17, and transforming growth factor- (TGF-) β1 were measured. The effect of Gal-9 on peripheral blood mononuclear cells (PBMC) was investigated in patients with normal coronary artery (NCA). Results. The lowest level of Gal-9 was found in the ST-segment elevation myocardial infarction (STEMI) group, followed by the non-ST-segment elevation ACS (NSTEACS), the NCA, and the stable angina pectoris (SAP) groups, respectively. Additionally, Gal-9 was found to be independently associated with hs-CRP, lipoprotein(a), and creatinine. Notably, Gal-9 was also noted to be an independent predictor of the Gensini score. Moreover, Gal-9 suppressed T-helper 17 (Th17) and expanded regulatory T cells (Tregs), resulting in decreased IL-17 production and increased secretion of TGF-β1. Conclusions. Serum Gal-9 is associated with not only coronary artery disease (CAD), but also the severity of coronary arteries stenosis. Gal-9 can expand Tregs and suppress Th17 development in activated PBMC, implying that Gal-9 has the potential to dampen the development of atherosclerosis and may be a new therapy for CAD.

Aggregation and fusion of low-density lipoproteins in vivo and in vitro

Low-density lipoproteins (LDLs, also known as 'bad cholesterol') are the major carriers of circulating cholesterol and the main causative risk factor of atherosclerosis. Plasma LDLs are 20- to 25-nm nanoparticles containing a core of cholesterol esters surrounded by a phospholipid monolayer and a single copy of apolipoprotein B (550 kDa). An early sign of atherosclerosis is the accumulation of LDL-derived lipid droplets in the arterial wall. According to the widely accepted 'response-to-retention hypothesis', LDL binding to the extracellular matrix proteoglycans in the arterial intima induces hydrolytic and oxidative modifications that promote LDL aggregation and fusion. This enhances LDL uptake by the arterial macrophages and triggers a cascade of pathogenic responses that culminate in the development of atherosclerotic lesions. Hence, LDL aggregation, fusion, and lipid droplet formation are important early steps in atherogenesis. In vitro, a variety of enzymatic and nonenzymatic modifications of LDL can induce these reactions and thereby provide useful models for their detailed analysis. Here, we summarize current knowledge of the in vivo and in vitro modifications of LDLs leading to their aggregation, fusion, and lipid droplet formation; outline the techniques used to study these reactions; and propose a molecular mechanism that underlies these pro-atherogenic processes. Such knowledge is essential in identifying endogenous and exogenous factors that can promote or prevent LDL aggregation and fusion in vivo and to help establish new potential therapeutic targets to decelerate or even block these pathogenic reactions.

Elevated serum chemerin in Chinese women with hyperandrogenic PCOS

OBJECTIVES

To compare serum chemerin levels between women with classic hyperandrogenic PCOS, euandrogenic PCOS and matched control subjects.

RESEARCH DESIGN AND METHODS

This study was carried out at the Second XiangYa Hospital between July 2012 and April 2013. Sixty-seven women with PCOS and 20 controls were included. Blood pressure, body mass index (BMI), waist to hip ratio (WHR), fasting insulin, fasting plasma glucose and blood serum hormone and blood lipid were measured. Transvaginal ultrasound was performed. Serum chemerin was measured by ELISA.

RESULTS

Serum chemerin was significantly higher in classic hyperandrogenic PCOS compared with euandrogenic PCOS and controls (311.07 ± 141.87 ng/mL versus 228.03 ± 119.66 ng/mL and 225.87 ± 86.44 ng/mL, p < 0.05). Serum chemerin was positively related to follicle count, ovarian volume, the level of testosterone, luteinizing hormone/follicle-stimulating hormone, low-density lipoprotein, triglycerides, fasting blood insulin, insulin resistance by homeostasis model assessment, WHR and BMI, while negatively related to the level of high-density lipoprotein. Multiple linear regression analyses revealed ovarian volumes and WHR were the significant influencing factors of chemerin (p < 0.05). The area under the receiver operating characteristic curve for chemerin reached a value of 0.684 (0.572-0.796, 95% confidence interval). The best compromise between sensitivity (80.0%) and specificity (47.6%) was obtained with a cutoff value of 200.94 ng/mL.

CONCLUSIONS

Serum chemerin level was increased in Chinese women with classic hyperandrogenic PCOS. Serum chemerin measurement offers a relatively moderate diagnostic potency with a sensitivity of 80.0% and a specificity of 47.6% at 200.94 ng/mL. This suggested that chemerin may be involved in the development of the metabolic syndrome of classic PCOS.

Elevated chemerin levels in Pakistani men: an interrelation with metabolic syndrome phenotypes

Chemerin is a novel protein linked to adipocyte differentiation and the development of metabolic imbalances. We sought to examine the relationship of chemerin with metabolic syndrome disturbances including body fat percentage, serum lipid, glucose, insulin levels and body fat percentage in lean and obese volunteers. A cross-sectional study of 90 randomly selected healthy males from Pakistan were divided into three groups as per Body Mass Index (BMI) criteria for South Asian Population. Anthropometric measurements were taken for BMI, waist circumference, hip circumference and body fat percentage, while serum analyses were performed for fasting blood glucose, fasting insulin, fasting lipid profile and serum chemerin. Associations between serum chemerin levels and body fat and other metabolic syndrome parameters were performed using ANOVA and multiple regression analyses. Data was presented as Mean±SD. In all statistical analyses p-values <0.05 were considered significant. Circulating chemerin levels were significantly higher in obese subjects with BMI greater than 25 kg/m² compared with those with a BMI below 25 kg/m² (P = 0.001). Serum chemerin levels were found to be independently and significantly associated with serum levels of cholesterol (P = 0.0160; r = 0.255), fasting glucose (P = 0.002; r = 0.323), HOMA-IR (P = 0.004; r = 0.300) and hip circumference (P = 0.021; r = 0.246). This demonstrates that chemerin levels are associated with obesity and dyslipidemia and may play a role in the development of insulin resistance. This data suggests that chemerin may serve as an independent marker in diagnosing these conditions even before they become clinically symptomatic.

What is the role of alternative biomarkers for coronary heart disease?

Predictive models for future risk of coronary heart disease (CHD) based on traditional risk factors, such as age, male gender, LDL cholesterol, HDL cholesterol, diabetes mellitus, hypertension, smoking and family history of premature CHD, are quite robust but leave room for further improvement. Thus, efforts are being made to assess additional biomarkers for CHD, such as, lipoprotein (a), C-reactive protein, fibrinogen, lipoprotein-associated phospholipase A2, homocysteine and others. However, none of the novel biomarkers has demonstrated improved prediction beyond traditional risk factor models in a consistent fashion across multiple cohorts. Many criteria have to be fulfilled before a biomarker can be considered clinically relevant. Another way is to develop new models predicting long-term or life-time risk of CHD. Further research using novel biomarkers and long-term predictive models has the potential to improve CHD risk prediction.

Biomarkers for predicting postmenopausal coronary heart disease

Coronary heart disease (CHD) is the main cause of death in post-menopausal women (PMW). Beyond the ‘traditional’ cardiovascular risk factors of CHD, newer biomarkers, reflecting inflammation, endothelial function and oxidative stress, have received growing consideration. We systematically reviewed the literature on the biomarkers for predicting CHD in PMW. C-reactive protein, IL-6 and Lipoprotein (a) have been consistently found to be associated with CHD risk in PMW. However, no evidence supports the existence of a causal and independent link between such biomarkers and CHD in PMW. Also, the new biomarkers only marginally improve cardiovascular risk prediction. Upcoming studies are needed to provide further evidence on the validity of the new biomarkers in PMW and to understand their relationships with hormone therapy, opening new avenues for prevention.

Use of B-type natriuretic peptide as a screening tool for left ventricular diastolic dysfunction in rheumatoid arthritis patients without clinical cardiovascular disease

OBJECTIVE

Patients with rheumatoid arthritis (RA) are at an increased risk for heart failure and left ventricular diastolic dysfunction (LVDD). B-type natriuretic peptide (BNP) may be useful to screen for LVDD in the general population. We compared the effectiveness of BNP as a screening tool for LVDD in RA and non-RA subjects without cardiovascular disease (CVD).

METHODS

Study subjects were recruited from population-based samples with and without RA, excluding subjects with CVD. LVDD was assessed by 2-dimensional and Doppler echocardiography and categorized as none, mild, moderate/severe, or indeterminate. Linear regression and proportional odds models evaluated the association between LVDD and BNP, adjusting for age, sex, and body mass index.

RESULTS

Among 231 RA and 1,730 non-RA subjects without CVD, BNP was significantly higher in subjects with moderate/severe LVDD compared to those with no or mild LVDD (P = 0.02 for RA and P < 0.001 for non-RA subjects). More RA subjects had elevated BNP than non-RA subjects (16% versus 9%; P < 0.001). Positive predictive value (25% in RA and 18% in non-RA subjects) and sensitivity (40% in RA and 26% in non-RA subjects) were similarly low in both cohorts, but specificity was significantly lower in RA than in non-RA subjects (89% versus 94%; P = 0.02).

CONCLUSION

While RA subjects were more likely to have elevated BNP, few RA patients with elevated BNP actually have LVDD. Also, normal BNP levels are less likely to rule out LVDD in RA than in non-RA subjects. Therefore, BNP may be less effective for screening in RA subjects compared to the general population.

[Adipocytokines in rheumatoid arthritis and obesity]

In obese rheumatoid arthritis (RA) patients inflammatory mechanisms and cardiovascular secondary disorders are possibly related to changed expression of adipocytokines. Various adipocytokines and inflammatory parameters were examined in 112 patients (23.2% men; 76.8% women) suffering from RA: leptin, adiponectin, visfatin, sCD40 L, CRP, and ESR. Average BMI was 27.6 (+/-5.6). Leptin and BMI as well as visfatin and BMI correlated positively, BMI and adiponectin, however, showed a negative correlation. Significant differences between normal-weight and obese RA patients were found in both leptin and adiponectin measurements. Visfatin showed a positive correlation with CRP; sCD40 ligand which is a marker for increased T-cell activity correlated with CRP and ESR. Patients with low adiponectin levels (<10 microg/ml) more often suffered from cardiovascular diseases (28.6%) than those with enhanced adiponectin (14.3%). Increased pro-inflammatory leptin and decreased anti-inflammatory adiponectin in obese RA patients can be associated with RA activity and enhanced cardiovascular risk.

Effects of phospholipase A(2) and its products on structural stability of human LDL: relevance to formation of LDL-derived lipid droplets

Hydrolysis and oxidation of LDL stimulate LDL entrapment in the arterial wall and promote inflammation and atherosclerosis via various mechanisms including lipoprotein fusion and lipid droplet formation. To determine the effects of FFA on these transitions, we hydrolyzed LDL by phospholipase A(2) (PLA(2)), removed FFA by albumin, and analyzed structural stability of the modified lipoproteins. Earlier, we showed that heating induces LDL remodeling, rupture, and coalescence into lipid droplets resembling those found in atherosclerotic lesions. Here, we report how FFA affect these transitions. Circular dichroism showed that mild LDL lipolysis induces partial β-sheet unfolding in apolipoprotein B. Electron microscopy, turbidity, and differential scanning calorimetry showed that mild lipolysis promotes LDL coalescence into lipid droplets. FFA removal by albumin restores LDL stability but not the protein conformation. Consequently, FFA enhance LDL coalescence into lipid droplets. Similar effects of FFA were observed in minimally oxidized LDL, in LDL enriched with exogenous FFA, and in HDL and VLDL. Our results imply that FFA promote lipoprotein coalescence into lipid droplets and explain why LDL oxidation enhances such coalescence in vivo but hampers it in vitro. Such lipid droplet formation potentially contributes to the pro-atherogenic effects of FFA.

Elevated serum chemerin levels are associated with the presence of coronary artery disease in patients with metabolic syndrome

OBJECTIVE

Patients with metabolic syndrome (MetS) are at a high risk for developing atherosclerosis and cardiovascular disease. Serum levels of chemerin have been found elevated in subjects with MetS and are associated with several cardiovascular factors. This study was undertaken to determine whether serum chemerin levels are associated with coronary artery disease (CAD) in patients with MetS.

METHODS

A total of 112 patients with MetS (66 patients with CAD and 46 without CAD) and 52 healthy subjects who underwent coronary angiography for the evaluation of CAD were enrolled in this study. Serum levels of chemerin were measured by enzyme-linked immunosorbent assay.

RESULTS

Serum chemerin levels were significantly elevated in MetS patients with CAD compared to in those without CAD and healthy subjects. MetS patients without CAD also had higher serum chemerin levels compared with healthy subjects. Multivariate logistic regression analysis revealed that serum chemerin levels were significantly associated with the presence of CAD in patients with MetS. Simple linear regression analysis showed that the serum levels of chemerin were positively correlated with body mass index (BMI), systolic blood pressure (SBP), serum triglycerides and C-reactive protein (CRP) in patients with MetS. Only BMI and CRP remained significantly associated with serum chemerin after multiple stepwise regression analysis.

CONCLUSION

Elevated serum chemerin levels could be considered as an independent predictive marker of the presence of CAD in patients with MetS.

Emerging therapies for atherosclerosis prevention and management

Atherosclerosis is a chronic immunoinflammatory disease involving medium and large arteries, resulting from a complex interaction between genetic and environmental risk factors. Acute atherosclerotic vascular disease largely results from thrombosis that supervenes on a disrupted atherosclerotic plaque. A healthy lifestyle coupled with management of modifiable risk factors reduces the adverse clinical consequences of atherothrombosis. Reducing low-density lipoprotein cholesterol levels using statins and other agents is the primary pharmacologic approach to stabilize atherosclerosis, but a large residual risk burden remains, stimulating the search for additional therapies for atherosclerosis management. This review focuses on new and emerging therapeutic strategies targeting atherosclerosis.