Relation between plasma adiponectin, high-sensitivity C-reactive protein, and coronary plaque components in patients with acute coronary syndrome

Plasma C-reactive protein is associated with a pro-inflammatory and adverse plaque phenotype

BACKGROUND AND AIMS

Systemic low-grade inflammation, measured by plasma high-sensitivity C-reactive protein (hsCRP) levels, is an important risk factor for atherosclerotic cardiovascular disease (ASCVD). To date, however, it is unknown whether plasma hsCRP is associated with adverse histological plaque features.

METHODS

Plaques were derived during carotid endarterectomy. Patients with hsCRP levels ≥2 mg/L were evaluated for pro-inflammatory and adverse plaque characteristics, as well as future ASCVD events, and compared with patients with low hsCRP levels. Logistic and linear regression analyses in addition to subdistribution hazard ratios were conducted, adjusted for cardiovascular risk factors.

RESULTS

A total of 1096 patients were included, of which 494 (46.2 %) had hsCRP levels ≥2 mg/L. Elevated hsCRP levels 2 mg/L were independently associated with levels of plaque interleukin 6, beta coefficient of 109.8 (95 % confidence interval (CI): 33.4, 186.5; p = 0.005) pg/L, interleukin 8 levels, 194.8 (110.4, 378.2; p = 0.03) pg/L and adiponectin plaque levels, -16.8 (-30.1, -3.6; p = 0.01) μg/L, compared with plaques from patients with low hsCRP levels. Histological analysis revealed increased vessel density in high hsCRP patients, odds ratio (OR) of 1.57 (1.20, 2.09; p = 0.001), larger lipid core, 1.35 (1.02, 1.73; p = 0.04), and increased macrophage content, 1.32 (1.02, 1.73; p = 0.04). Over a 3-year follow-up period, hsCRP levels ≥2 mg/L were associated with a hazard ratio of 1.81 (1.03, 3.16; p = 0.04) for coronary artery disease event risk.

CONCLUSIONS

The distinct inflammatory and histological features observed in carotid plaques among individuals with hsCRP levels ≥2 mg/L underscore the utility of plasma hsCRP as a potent identifier for patients harboring high-risk plaques.

Colchicine in atherosclerotic cardiovascular disease

Inflammation has a direct role in the development of atherosclerotic vascular disease, and oral colchicine displays broad anti-inflammatory properties. Several large, randomised controlled trials (RCTs) have evaluated colchicine's impact on cardiovascular outcomes. Results from a meta-analysis of these trials demonstrate that colchicine reduces the risk of recurrent major adverse cardiovascular events (MACEs) by 25%, leading to its recent approval by the Food and Drug Administration for the treatment and prevention of cardiovascular disease. Despite this, colchicine has not been shown to confer any survival benefit in these trials. The non-significant reduction in cardiovascular death of 18% (95% CI: 45% decrease to 23% increase) is outweighed by a more prominent, borderline non-significant increase in the risk of non-cardiovascular death by 38% (95% CI: 1% decrease to 92% increase). Key populations including those with heart failure, those undergoing surgical revascularisation, women, elderly individuals and non-Caucasians are under-represented in completed trials, which limits generalisability. C reactive protein has been proposed as a biomarker for colchicine response and shows promise for identifying a high-risk population where the benefit on MACE reduction and specifically reduced cardiovascular death might outweigh any real increased risk of non-cardiovascular death; however, this approach is still to be validated in ongoing RCTs. In conclusion, while colchicine shows promise in reducing MACE, its net risk-benefit profile requires further elucidation before its widespread adoption into clinical practice for the secondary prevention of atherosclerotic cardiovascular disease. Much more large-scale, long-term trial data are still needed in this space.

Investigation of the clinical effects of acipimox in patients with vulnerable carotid atherosclerosis

OBJECTIVE

To investigate the clinical effects of acipimox in patients with vulnerable carotid atherosclerosis.

METHODS

80 patients with vulnerable carotid atherosclerosis who were admitted to the Department of Cardiology in Wuxi Second People's Hospital between February 2020 and October 2021 were enrolled in this study. All of these patients were randomly divided into an observation group (n = 40), who were given acipimox and conventional treatment, and a control group (n = 40), who were given conventional treatment. The levels of blood lipids and adiponectin (APN), the carotid intima-media thickness (IMT), the area, thickness and number of CAS, peak systolic velocities (PSV) and end-diastolic blood velocity (EDV) of common carotid artery (CCA), and the level of inflammatory markers were measured and compared between the two groups pretherapy and posttreatment. Then, the adverse events were collected and compared between the two groups posttreatment.

RESULTS

The demographics and basic clinical characteristics were not significantly different between the two groups. At posttreatment, the levels of TC, LDL-C, ANP, IL-6, TNF-α and hs-CRP in the observation group were significantly lower than those in the control group at posttreatment. Moreover, the IMT and the area and thickness of CAS in the observation group were significantly lower than those in the control group. After treatment, PSV was lower and EDV was higher in two groups than before treatment; after treatment, compared with control group, PSV in observation group was lower, while EDV was higher. Most importantly, the rate of adverse events was similar in the two groups.

CONCLUSIONS

Acipimox reduced the blood lipid levels in patients with vulnerable carotid atherosclerosis. It also stabilized vulnerable plaques and reduced CAS.

Biomarkers to monitor the prognosis, disease severity, and treatment efficacy in coronary artery disease

INTRODUCTION

Coronary Artery Disease (CAD) is a prevalent condition characterized by the presence of atherosclerotic plaques in the coronary arteries of the heart. The global burden of CAD has increased significantly over the years, resulting in millions of deaths annually and making it the leading health-care expenditure and cause of mortality in developed countries. The lack of cost-effective strategies for monitoring the prognosis of CAD warrants a pressing need for accurate and efficient markers to assess disease severity and progression for both reducing health-care costs and improving patient outcomes.

AREA COVERED

To effectively monitor CAD, prognostic biomarkers and imaging techniques play a vital role in risk-stratified patients during acute treatment and over time. However, with over 1,000 potential markers of interest, it is crucial to identify the key markers with substantial utility in monitoring CAD progression and evaluating therapeutic interventions. This review focuses on identifying and highlighting the most relevant markers for monitoring CAD prognosis and disease severity. We searched for relevant literature using PubMed and Google Scholar.

EXPERT OPINION

By utilizing the markers discussed, health-care providers can improve patient care, optimize treatment plans, and ultimately reduce health-care costs associated with CAD management.

Serial Changes in Exercise Capacity, NT-proBNP, and Adiponectin in Patients with Acute Coronary Syndrome before and after Phase II Rehabilitation as well as at the 12-Month Follow-Up

Background. Acute coronary syndrome (ACS) causes pathophysiological changes in exercise capacity, N-terminal part of pro-brain natriuretic peptide (NT-proBNP), and adiponectin that impact the course of coronary artery disease and clinical outcomes after cardiac rehabilitation (CR). However, the serial changes and the relationship between the changes in these parameters for a prolonged term remain uninvestigated. Methods. Eighty-one patients with ACS underwent a three- or four-week CR program after acute care and were followed up for 12 months. Exercise capacity on a cycle ergometer and blood levels of NT-proBNP and adiponectin were determined before and after CR as well as at the 12-month follow-up. Results. Exercise capacity increased from 100 watts (in median) before CR to 138 watts after CR and 150 watts at 12 months. The NT-proBNP level (526 pg/ml before CR) remained almost unchanged after CR (557 pg/ml) and then decreased at 12 months (173 pg/ml). The adiponectin level (14.5 µg/ml before CR) increased after CR (16.0 µg/ml) and at 12 months (17.2 µg/ml). There was no significant correlation among the changes in these parameters at each observation time point. Conclusion. During the observation period from before CR to the 12-month follow-up, exercise capacity, NT-proBNP, and adiponectin underwent significant changes; however, these changes were independent from each other and not correlated linearly, and they provide complementary information in clinical practice. Thus, all these parameters should be included and determined at different time points for a prolonged period of time.

Atheroprotective Roles of Adiponectin via CCL2 Inhibition

Aim: Adiponectin (APN) exhibits different atheroprotective effects, and we have previously reported that APN function is modulated by its binding proteins, E-selectin ligand 1, Mac-2 binding protein, and cystatin C. In the present study, we aimed to identify a novel atheroprotective mechanism of APN via C–C motif chemokine 2 (CCL2).

Methods: We conducted iMAP ^® -intravascular ultrasound (IVUS) in 111 Japanese male patients with stable angina. The plaque characteristics were determined where “plaque burden” [(EEM CSA − lumen CSA)/(EEM CSA)×100 (%)] ＞50%, and their correlation with serum CCL2 and APN levels was analyzed. Using western blot analysis, the effects of APN on the biological effects of CCL2 were examined in their mutual binding by co-immunoprecipitation assay, the monocyte migration, and the phosphorylation of MAP kinases.

Results: In a clinical study, we found that the percentage of plaque in the culprit lesion was correlated positively with serum CCL2 and negatively with serum APN levels, with significance. We identified CCL2 as a novel APN-binding serum protein using immunoprecipitation and western blot analysis. CCL2-induced phosphorylation of MAP kinases and monocyte migration was significantly attenuated by APN in vitro .

Conclusion: The opposite association of APN and CCL2 on the percentage of coronary plaque might be caused by their direct interaction and competitive functions on monocyte migration.

Low Plasma Adiponectin Levels Are Associated With Vulnerable Plaque Features in Patients With Acute Coronary Syndrome: An Optical Coherence Tomography Study

BACKGROUND

Vulnerable plaques are the primary cause of acute coronary syndrome (ACS). The association between in-vivo plaque vulnerability and adiponectin levels in ACS still remains to be determined.

OBJECTIVE

The purpose of this study was to investigate the correlation between adiponectin levels and vulnerable plaque features in ACS patients.

METHODS

We enrolled 107 ACS patients admitted to our institution; 83 with Non-ST elevation ACS (NSTE-ACS) and 24 with ST-elevation myocardial infarction (STEMI). Adiponectin levels were measured in these patients. Coronary angiography and subsequent optical coherence tomography (OCT) analysis of culprit lesions were performed.

RESULTS

Adiponectin level was lower in patients with complex angiographic lesions, compared to those with non-complex lesions (7.13 ± 3.04 vs. 8.94 ± 2.84 μg/ml, P = 0.002). Adiponectin level was lower in patients with plaque rupture (PR), micro-thrombi, and thin cap fibroatheroma (TCFA), compared to those with non-vulnerable features (7.19 ± 2.95 vs 8.79 ± 3.02 μg/ml, P = 0.007 & 7.29 ± 2.97 vs 8.44 ± 3.09 μg/ml, P = 0.04 and 4.76 ± 0.65 vs 9.74 ± 2.35 μg/ml, P < 0.001 μg/ml respectively). There was a significant negative correlation between adiponectin levels and lipid rich plaque extent and maximum lipid arc (r = -0.05, P < 0.001 & r = -0.03, P = 0.03, respectively). However, a significant positive correlation was observed between adiponectin levels and fibrous cap thickness (r = 0.95, P < 0.001).

CONCLUSION

Low adiponectin levels were associated with complex angiographic lesions and vulnerable plaque features in ACS patients, where there was a significant correlation between it and PR, TCFA, and lipid rich plaque.

Adiponectin suppresses amyloid-β oligomer (AβO)-induced inflammatory response of microglia via AdipoR1-AMPK-NF-κB signaling pathway

Background

Microglia-mediated neuroinflammation is important in Alzheimer’s disease (AD) pathogenesis. Extracellular deposition of β-amyloid (Aβ), a major pathological hallmark of AD, can induce microglia activation. Adiponectin (APN), an adipocyte-derived adipokine, exerts anti-inflammatory effects in the periphery and brain. Chronic APN deficiency leads to cognitive impairment and AD-like pathologies in aged mice. Here, we aim to study the role of APN in regulating microglia-mediated neuroinflammation in AD.

Methods

Inflammatory response of cultured microglia (BV2 cells) to AβO and effects of APN were studied by measuring levels of proinflammatory cytokines (tumor necrosis factor α [TNFα] and interleukin-1β [IL-1β]) in cultured medium before and after exposure to AβO, with and without APN pretreatment. Adiponectin receptor 1 (AdipoR1) and receptor 2 (AdipoR2) were targeted by small interference RNA. To study the neuroprotective effect of APN, cultured HT-22 hippocampal cells were treated with conditioned medium of AβO-exposed BV2 cells or were co-cultured with BV2 cells in transwells. The cytotoxicity of HT-22 hippocampal cells was assessed by MTT reduction. We generated APN-deficient AD mice (APN^−/−5xFAD) by crossing APN-knockout mice with 5xFAD mice to determine the effects of APN deficiency on microglia-mediated neuroinflammation in AD.

Results

AdipoR1 and AdipoR2 were expressed in BV2 cells and microglia of mice. Pretreatment with APN for 2 h suppressed TNFα and IL-1β release induced by AβO in BV2 cells. Additionally, APN rescued the decrease of AMPK phosphorylation and suppressed nuclear translocation of nuclear factor kappa B (NF-κB) induced by AβO. Compound C, an inhibitor of AMPK, abolished these effects of APN. Knockdown of AdipoR1, but not AdipoR2 in BV2 cells, inhibited the ability of APN to suppress proinflammatory cytokine release induced by AβO. Moreover, pretreatment with APN inhibited the cytotoxicity of HT-22 cells co-cultured with AβO-exposed BV2 cells. Lastly, APN deficiency exacerbated microglia activation in 9-month-old APN^−/−5xFAD mice associated with upregulation of TNFα and IL-1β in the cortex and hippocampus.

Conclusions

Our findings demonstrate that APN inhibits inflammatory response of microglia to AβO via AdipoR1-AMPK-NF-κB signaling, and APN deficiency aggravates microglia activation and neuroinflammation in AD mice. APN may be a novel therapeutic agent for inhibiting neuroinflammation in AD.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1492-6) contains supplementary material, which is available to authorized users.

Adiponectin in Relation to Coronary Plaque Characteristics on Radiofrequency Intravascular Ultrasound and Cardiovascular Outcome

Background

Prospective data on the associations of adiponectin with in-vivo measurements of degree, phenotype and vulnerability of coronary atherosclerosis are currently lacking.

Objective

To investigate the association of plasma adiponectin with virtual histology intravascular ultrasound (VH-IVUS)-derived measures of atherosclerosis and with major adverse cardiac events (MACE) in patients with established coronary artery disease.

Methods

In 2008-2011, VH-IVUS of a non-culprit non-stenotic coronary segment was performed in 581 patients undergoing coronary angiography for acute coronary syndrome (ACS, n = 318) or stable angina pectoris (SAP, n = 263) from the atherosclerosis-intravascular ultrasound (ATHEROREMO-IVUS) study. Blood was sampled prior to coronary angiography. Coronary plaque burden, tissue composition, high-risk lesions, including VH-IVUS-derived thin-cap fibroatheroma (TCFA), were assessed. All-cause mortality, ACS, unplanned coronary revascularization were registered during a 1-year-follow-up. All statistical tests were two-tailed and p-values < 0.05 were considered statistically significant.

Results

In the full cohort, adiponectin levels were not associated with plaque burden, nor with the various VH-tissue types. In SAP patients, adiponectin levels (median[IQR]: 2.9(1.9-3.9) µg/mL) were positively associated with VH-IVUS derived TCFA lesions, (OR[95%CI]: 1.78[1.06-3.00], p = 0.030), and inversely associated with lesions with minimal luminal area (MLA) ≤ 4.0 mm² (OR[95%CI]: 0.55[0.32-0.92], p = 0.025). In ACS patients, adiponectin levels (median[IQR]: 2.9 [1.8-4.1] µg/mL)were not associated with plaque burden, nor with tissue components. Positive association of adiponectin with death was present in the full cohort (HR[95%CI]: 2.52[1.02-6.23], p = 0.045) and (borderline) in SAP patients (HR[95%CI]: 8.48[0.92-78.0], p = 0.058). In ACS patients, this association lost statistical significance after multivariable adjustment (HR[95%CI]: 1.87[0.67-5.19], p = 0.23).

Conclusion

In the full cohort, adiponectin levels were associated with death but not with VH-IVUS atherosclerosis measures. In SAP patients, adiponectin levels were associated with VH-IVUS-derived TCFA lesions. Altogether, substantial role for adiponectin in plaque vulnerability remains unconfirmed.

Epicardial adipose tissue density and volume are related to subclinical atherosclerosis, inflammation and major adverse cardiac events in asymptomatic subjects

BACKGROUND

We investigated whether epicardial adipose tissue (EAT) volume and density are related to early atherosclerosis, plaque inflammation and major adverse cardiac events (MACE, cardiac death and myocardial infarction) in asymptomatic subjects.

METHODS

EAT volume and density were quantified from non-contrast cardiac CT in 456 asymptomatic individuals (age 60.3 ± 8.3; 68% with CCS>0) from the prospective EISNER trial. EAT volume and density were examined in relation to coronary calcium score (CCS), inflammatory biomarkers and MACE.

RESULTS

EAT volume was higher and EAT density lower in subjects with coronary calcium compared to subjects without [89 vs 74 cm³, p < 0.001] [-76.9 vs -75.7 HU,p = 0.024]. EAT volume was lowest in individuals with no coronary calcium and was significant higher in subjects with early atherosclerosis (CCS 1-99) [74 vs 87 cm³,p = 0.016] and in subjects with more advanced atherosclerosis (CCS≥100) [89 cm³,p = 0.002]). EAT volume was independently related to serum levels of PAI-1, and MCP-1 and inversely related to adiponectin and HDL-cholesterol (p < 0.05). EAT density was inversely related to PAI-1 and LDL-cholesterol and positively associated to adiponectin, sICAM-1 and HDL-cholesterol (p < 0.05). EAT density was more significantly associated with MACE [(HR 0.8, 95%CI:0.7-0.98), p = 0.029] than EAT volume or CCS.

CONCLUSION

EAT volume was higher and density lower in subjects with coronary calcium compared to subjects with CCS = 0, with similar EAT volume in CCS<100 and CCS≥100. Lower EAT density and increased EAT volume were associated with coronary calcification, serum levels of plaque inflammatory markers and MACE, suggesting that dysfunctional EAT may be linked to early plaque formation and inflammation.

Identification of Risk Factors Influencing In-Stent Restenosis with Acute Coronary Syndrome Presentation

Although the angiographic rates of in-stent restenosis (ISR) at later months have reduced dramatically with the introduction of drug-eluting stents (DESs), some patients with ISR after implantation of DES present with acute coronary syndrome (ACS). Here, we sought to identify parameters influencing the likelihood of restenosis with ACS presentation after DES implantation. Stented patients (n=3,817) with DESs in the Korea University Anam Hospital percutaneous coronary intervention registry were reviewed retrospectively for inclusion. In this database, 247 age- and sex-matched patients (6.5%) with ISR were allocated to either the Stable ISR group (n=78) or the ACS ISR group (n=73). Predictors of in-stent restenosis were identified with Cox regression analyses. Age (hazard ratio [HR], 1.14; 95% confidence interval [CI], 1.02 to 1.27; p=0.026), diabetes (HR, 8.40; 95% CI, 1.30 to 54.1; p=0.025), use of aspirin (HR, 0.003; 95% CI, 0.0001 to 0.63; p=0.03), clopidogrel (HR, 0.005; 95% CI, 0.001 to 0.121; p=0.001), renin-angiotensin system (RAS) blocker (HR, 0.02; 95% CI, 0.003 to 0.14; p<0.001), use of first -generation DES (HR, 0.07; 95% CI, 0.009 to 0.59; p=0.014), and matrix metalloproteinase 2 (MMP-2) levels (HR, 1.120; 95% CI, 1.001 to 1.190; p=0.004) during follow-up angiograms were significant predictors of ISR with ACS presentation during the 3 year follow-up. Age, diabetes, the use of first generation DES, and increased MMP-2 levels were significant predictors of ISR with ACS presentation; moreover, the use of aspirin, clopidogrel, RAS blocker, and the use of second generation DESs prevented ISR with ACS presentation.

Cystatin C-Adiponectin Complex in Plasma Associates with Coronary Plaque Instability

Aim: Adiponectin (APN) is an adipocyte-derived bioactive molecule with antiatherogenic properties. We previously reported that cystatin C (CysC) abolished the anti-atherogenic effects of APN. We aimed to elucidate the clinical significance of CysC–APN complex in patients with coronary artery disease (CAD).

Methods: We enrolled 43 stable CAD male patients to examine the relationship between CysC–APN complex and coronary plaque characteristics. Serum was immunoprecipitated by the anti-APN antibody and immunoblotted by the anti-CysC antibody to demonstrate the presence of CysC–APN complexes in vivo. To confirm their binding in vitro, HEK293T cell lysates overexpressing myc-APN and FLAG-CysC were immunoprecipitated with an anti-myc or anti-FLAG antibody, followed by immunoblotting with an anti-APN or anti-CysC antibody.

Results: CysC was identified as a specific co-immunoprecipitant with APN by the anti-APN antibody in human serum. In vitro, FLAG-CysC was co-immunoprecipitated with myc-APN by the antimyc antibody and myc-APN was co-immunoprecipitated with FLAG-CysC by the anti-FLAG antibody. Among CAD patients, serum CysC–APN complex levels negatively correlated with fibrotic components of coronary plaques and positively correlated with either necrotic or lipidic plus necrotic components. Plaque burden negatively correlated with serum APN levels but not serum CysC–APN complex levels. Serum CysC levels had no association with plaque characteristics. In multivariate analysis, CysC–APN complex levels were identified as the strongest negative factor for fibrotic components and the strongest positive factor for both necrotic and lipidic plus necrotic components.

Conclusion: Measuring serum CysC–APN complex levels is helpful for evaluating coronary plaque instability in CAD patients.

Darapladib, a Lipoprotein-Associated Phospholipase A2 Inhibitor, Reduces Rho Kinase Activity in Atherosclerosis

PURPOSE

Increased lipoprotein-associated phospholipase A2 (Lp-PLA2) activity and Rho kinase activity may be associated with atherosclerosis. The principal aim of this study was to examine whether darapladib (a selective Lp-PLA2 inhibitor) could reduce the elevated Lp-PLA2 and Rho kinase activity in atherosclerosis.

MATERIALS AND METHODS

Studies were performed in male Sprague-Dawley rats. The atherosclerosis rats were prepared by feeding them with a high-cholesterol diet for 10 weeks. Low-dose darapladib (25 mg·kg⁻¹·d⁻¹) and high-dose darapladib (50 mg·kg⁻¹·d⁻¹) interventions were then administered over the course of 2 weeks.

RESULTS

The serum levels of triglycerides, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), high-sensitivity C-reactive protein (hs-CRP), and Lp-PLA2, significantly increased in atherosclerosis model groups, as did Rho kinase activity and cardiomyocyte apoptosis (p<0.05 vs. sham group), whereas nitric oxide (NO) production was reduced. Levels of TC, LDL-C, CRP, Lp-PLA2, and Rho kinase activity were respectively reduced in darapladib groups, whereas NO production was enhanced. When compared to the low-dose darapladib group, the reduction of the levels of TC, LDL-C, CRP, and Lp-PLA2 was more prominent in the high-dose darapladib group (p<0.05), and the increase of NO production was more prominent (p<0.05). Cardiomyocyte apoptosis of the high-dose darapladib group was also significantly reduced compared to the low-dose darapladib group (p<0.05). However, there was no significant difference in Rho kinase activity between the low-dose darapladib group and the high-dose darapladib group (p>0.05).

CONCLUSION

Darapladib, a Lp-PLA2 inhibitor, leads to cardiovascular protection that might be mediated by its inhibition of both Rho kinase and Lp-PLA2 in atherosclerosis.

Enriched environment decreases microglia and brain macrophages inflammatory phenotypes through adiponectin-dependent mechanisms: Relevance to depressive-like behavior

Regulation of neuroinflammation by glial cells plays a major role in the pathophysiology of major depression. While astrocyte involvement has been well described, the role of microglia is still elusive. Recently, we have shown that Adiponectin (ApN) plays a crucial role in the anxiolytic/antidepressant neurogenesis-independent effects of enriched environment (EE) in mice; however its mechanisms of action within the brain remain unknown. Here, we show that in a murine model of depression induced by chronic corticosterone administration, the hippocampus and the hypothalamus display increased levels of inflammatory cytokines mRNA, which is reversed by EE housing. By combining flow cytometry, cell sorting and q-PCR, we show that microglia from depressive-like mice adopt a pro-inflammatory phenotype characterized by higher expression levels of IL-1β, IL-6, TNF-α and IκB-α mRNAs. EE housing blocks pro-inflammatory cytokine gene induction and promotes arginase 1 mRNA expression in brain-sorted microglia, indicating that EE favors an anti-inflammatory activation state. We show that microglia and brain-macrophages from corticosterone-treated mice adopt differential expression profiles for CCR2, MHC class II and IL-4recα surface markers depending on whether the mice are kept in standard environment or EE. Interestingly, the effects of EE were abolished when cells are isolated from ApN knock-out mouse brains. When injected intra-cerebroventricularly, ApN, whose level is specifically increased in cerebrospinal fluid of depressive mice raised in EE, rescues microglia phenotype, reduces pro-inflammatory cytokine production by microglia and blocks depressive-like behavior in corticosterone-treated mice. Our data suggest that EE-induced ApN increase within the brain regulates microglia and brain macrophages phenotype and activation state, thus reducing neuroinflammation and depressive-like behaviors in mice.

Inflammation, plaque progression and vulnerability: evidence from intravascular ultrasound imaging

Increasing evidence points to a critical role of inflammation in the development and propagation of atherosclerotic cardiovascular disease. Pathological studies in human and animal models have elucidated specific inflammatory mediators contributing to the progression and rupture of atherosclerotic plaque in the artery wall. These observations not only outline the importance of inflammation in atheroma progression but also the potential of anti-inflammatory therapeutic approaches to prevent and stabilize atherosclerotic disease. Intravascular ultrasonography enables direct atheroma visualization in vivo. Additionally, refinements in ultrasound technology permitting radiofrequency backscatter analysis enhance plaque characterization associated with disease instability. These imaging modalities will continue to provide opportunities for evaluating novel inflammatory mechanisms and anti-inflammatory therapies.

Gender-Specific Associations between Circulating T-Cadherin and High Molecular Weight-Adiponectin in Patients with Stable Coronary Artery Disease

Close relationships exist between presence of adiponectin (APN) within vascular tissue and expression of T-cadherin (T-cad) on vascular cells. APN and T-cad are also present in the circulation but here their relationships are unknown. This study investigates associations between circulating levels of high molecular weight APN (HMW-APN) and T-cad in a population comprising 66 women and 181 men with angiographically proven stable coronary artery disease (CAD). Plasma HMW-APN and T-cad were measured by ELISA and analysed for associations with baseline clinical characteristics and with each other. In multivariable analysis BMI and HDL were independently associated with HMW-APN in both genders, while diabetes and extent of coronary stenosis were independently associated with T-cad in males only. Regression analysis showed no significant association between HMW-APN and T-cad in the overall study population. However, there was a negative association between HMW-APN and T-cad (P=0.037) in a subgroup of young men (age <60 years, had no diabetes and no or 1-vessel CAD) which persisted after multivariable analysis with adjustment for all potentially influential variables (P=0.021). In the corresponding subgroup of women there was a positive association between HMW-APN and T-cad (P=0.013) which disappeared after adjustment for HDL. After exclusion of the young men, a positive association (P=0.008) between HMW-APN and T-cad was found for the remaining participants of the overall population which disappeared after adjustment for HDL and BMI. The existence of opposing correlations between circulating HMW-APN and T-cad in male and female patient populations underscores the necessity to consider gender as a confounding variable when evaluating biomarker potentials of APN and T-cad.

Elevated serum levels of soluble Axl in acute coronary syndrome

BACKGROUND

Morbidities related to atherosclerosis, such as acute coronary syndrome (ACS), remain the leading cause of mortality. Axl is a receptor tyrosine kinase that is expressed in mammalian vascular and immune cells. Axl signaling is involved in the regulation of the inflammatory response. A considerable amount of evidence indicates that inflammation is responsible for the development of atherosclerosis in patients with ACS.

METHODS

To assess the relation of Axl and ACS, we recruited 64 patients with coronary heart disease: 34 with ACS, 30 with stable coronary heart disease, and 24 apparently healthy controls. Serum concentrations of soluble Axl (sAxl) were quantified by enzyme-linked immunosorbent assay. High-sensitivity C-reactive protein, tumor necrosis factor alpha, troponin I, and other routine biochemical markers were also measured.

RESULTS

The levels of sAxl were significantly higher in patients with ACS than in the controls (P=0.005). Furthermore, correlation analysis indicated that sAxl was significantly associated with serum levels of high-sensitivity C-reactive protein (r=0.283, P=0.008), tumor necrosis factor alpha (r=0.565, P<0.001), and troponin I (r=0.264, P=0.013). Logistic regression analysis (odds ratio=1.038, 95% confidence interval, 1.008-1.069, P=0.012) indicated a significant association between sAxl and ACS.

CONCLUSIONS

Serum levels of sAxl correlate to inflammatory biochemical markers. These findings demonstrate for the first time that sAxl does have a role in ACS, presumably connected to the inflammation.

Novel Biomarkers: Utility in Patients with Acute Chest Pain and Relationship to Coronary Artery Disease on Coronary CT Angiography

Acute chest pain remains one of the most common patient presentations encountered in the emergency department. With the evolution of biomarkers and improvement in cardiac imaging there has been advancement in risk stratification of patients, but millions of dollars continue to be spent in the assessment of chest pain. Investigators have explored possible comparative alternatives to the traditional work up of chest pain. In this review, we will discuss the current state of biomarker use in the evaluation of acute chest pain. We will review established and emerging circulating biomarkers and their addition to cardiac CT for appropriate diagnosis of coronary artery disease.

Release Kinetics of Inflammatory Biomarkers in a Clinical Model of Acute Myocardial Infarction

Rationale:

Inflammation in the setting of acute myocardial infarction (MI) has been linked to risk stratification; however, the release kinetics of inflammatory biomarkers in patients with acute MI has been difficult to establish.

Objective:

The aim of this study was to determine the kinetics of changes in the levels of several biomarkers specifically linked to inflammation after transcoronary ablation of septal hypertrophy, a procedure that mimics acute MI.

Methods and Results:

We analyzed release kinetics of C-reactive protein, high-sensitivity C-reactive protein, interleukin-6, soluble CD40 ligand, and peripheral blood leukocyte subsets in patients (n=21) undergoing transcoronary ablation of septal hypertrophy. Blood samples were collected before transcoronary ablation of septal hypertrophy and at various times after transcoronary ablation of septal hypertrophy. Serum levels of C-reactive protein were increased at 24 hours (1.0 mg/dL [interquartile range [IQR], 0.7–1.75] versus 0.2 mg/dL [IQR, 0.1–1.05] at baseline [BL]; P <0.001), whereas high-sensitivity C-reactive protein increased as early as 8 hours (2.68 mg/L [IQR, 1.23–11.80] versus 2.17 mg/L [IQR, 1.15–5.06] at BL; P =0.002). Interleukin-6 was significantly increased at 45 minutes (2.59 pg/mL [IQR, 1.69–5.0] versus 1.5 pg/mL [IQR, 1.5–2.21] at BL; P =0.002), and soluble CD40 ligand was significantly decreased at 60 minutes (801.6 pg/mL [IQR, 675.0–1653.5] versus 1750.0 pg/mL [IQR, 1151.0–2783.0] at BL; P =0.016). Elevated counts of polymorphonuclear neutrophils were detectable at 15 minutes, with a significant increase at 2 hours (6415 cells/μL [IQR, 5288–7827] versus 4697 cells/μL [IQR, 2892–5620] at BL; P =0.004). Significant monocytosis was observed at 24 hours (729 cells/μL [IQR, 584–1344] versus 523 cells/μL [IQR, 369–701] at BL; P =0.015).

Conclusions:

Interleukin-6 and neutrophil granulocytes showed a continuous rise at all prespecified time points after induction of MI. Our results provide valuable additional evidence of the diagnostic value of inflammatory biomarkers in the setting of early acute MI.

Macrophage polarization phenotype regulates adiponectin receptor expression and adiponectin anti-inflammatory response

Adiponectin (APN), a pleiotropic adipokine that exerts anti-inflammatory, antidiabetic, and antiatherogenic effects through its receptors (AdipoRs), AdipoR1 and AdipoR2, is an important therapeutic target. Factors regulating AdipoR expression in monocyte/macrophages are poorly understood, and the significance of polarized macrophage activation in controlling AdipoR expression and the APN-mediated inflammatory response has not been investigated. The aim of this study was to investigate whether the macrophage polarization phenotype controls the AdipoR expression and APN-mediated inflammatory response. With the use of mouse bone marrow and peritoneal macrophages, we demonstrate that classical activation (M1) of macrophages suppressed (40-60% of control) AdipoR expression, whereas alternative activation (M2) preserved it. Remarkably, the macrophage polarization phenotypes produced contrasting inflammatory responses to APN (EC50 5 µg/ml). In M1 macrophages, APN induced proinflammatory cytokines, TNF-α, IL-6, and IL-12 (>10-fold of control) and AdipoR levels. In contrast, in M2 macrophages, APN induced the anti-inflammatory cytokine IL-10 without altering AdipoR expression. Furthermore, M1 macrophages adapt to a cytokine environment by reversing AdipoR expression. APN induced AdipoR mRNA and protein expression by up-regulating liver X receptor-α (LXRα) in macrophages. These results provide the first evidence that macrophage polarization is a key determinant regulating AdipoR expression and differential APN-mediated macrophage inflammatory responses, which can profoundly influence their pathogenic role in inflammatory and metabolic disorders.

Chemerin is a novel biomarker of acute coronary syndrome but not of stable angina pectoris

BACKGROUND

Recent evidence demonstrated that the circulating adipokines were associated with the onset of acute coronary syndrome (ACS) including unstable angina pectoris (UAP) and acute myocardial infarction (AMI). As a novel adipokine, chemerin has been related to atherosclerosis and the presence of coronary artery disease. However, the plasma levels of chemerin in patients with ACS have yet to be investigated.

METHODS

Plasma levels of chemerin and adiponectin were measured by an enzyme-linked immunosorbent assay (ELISA) in 60 patients with stable angina pectoris (SAP), 60 patients with UAP, 60 patients with AMI and 40 control patients. Left ventricular end-diastolic diameter (LVEDD) and left ventricular ejection fraction (LVEF) were measured using a GE ViVid E7 ultrasonography machine, and the severity of coronary stenosis in patients was estimated with a Gensini coronary score following coronary angiography.

RESULTS

Plasma chemerin levels were significantly higher in ACS patients than in the control and SAP groups, while plasma adiponectin levels were significantly lower in ACS patients than the control group. A correlation analysis revealed that plasma chemerin levels were positively correlated with the levels of C-reactive protein (CRP) (r = 0.29, P < 0.01) and LVEDD (r = 0.27, P < 0.01) but negatively correlated with LVEF (r = -0.45, P < 0.01) and that plasma adiponectin levels were positively correlated with LVEF (r = 0.53, P < 0.01) but negatively correlated with CRP (r = -0.33, P < 0.01) and LVEDD (r = -0.30, P < 0.01). Although significant correlations between chemerin, adiponectin and BMI or the Gensini coronary score were found in patients with SAP, neither chemerin nor adiponectin was correlated with BMI and the Gensini coronary score in patients with ACS. Furthermore, both chemerin (OR 1.103, 95% CI 1.065 to 1.142; P = 0.001) and adiponectin (OR 0.871, 95% CI 0.776 to 0.970; P = 0.018) were independently associated with the presence of ACS.

CONCLUSIONS

Chemerin is a novel biomarker of acute coronary syndrome but not of stable angina pectoris.

Elevated lipoprotein-associated phospholipase A2 is associated with progression of nonculprit lesions after percutaneous coronary intervention

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an enzyme that hydrolyzes oxidized phospholipids to generate bioactive proatherogenic products. Nonculprit lesions have been assumed to contribute to the pathogenesis of recurrent acute coronary syndrome (ACS). The role of LP-PLA2 in the progression of nonculprit coronary lesions after successful percutaneous coronary intervention (PCI) remains unclear. Our study included 123 patients with ACS who underwent initial PCI and a long-term follow-up (mean interval, one year) with coronary angiography. Among them, 19 patients were diagnosed as the progression of nonculprit lesions, based on the presence of at least one of the following factors: (1) ≥ 10% reduction in the diameter of a preexisting ≥ 50% stenosis; (2) ≥ 30% reduction in the diameter of a < 50% stenosis; and (3) early-onset stenosis with ≥ 30% reduction in the diameter of a segment that was normal on the primary angiogram. Blood sampling was drawn from all patients at 12-14 hours after PCI. The ACS patients with progression had higher total cholesterol (4.47 ± 1.02 mmol/L vs. 3.59 ± 0.57 mmol/L, P < 0.05), higher levels of Lp-PLA2 activity (14.39 ± 6.13 nmol/min/ml vs. 8.86 ± 3.14 nmol/min/ml, P < 0.001) and a higher proportion of multi-vessel disease than those without progression. Multivariate logistic regression analysis showed that Lp-PLA2 activity (β = 0.024, P = 0.005) was an independent predictor for rapid progression of nonculprit coronary lesions. In conclusion, elevated Lp-PLA2 activity is associated with rapid progression of nonculprit coronary lesions in ACS patients who underwent PCI.

Clinical correlates and prognostic value of flow mediated dilation in patients with non-ST segment elevation acute coronary syndromes

Endothelial dysfunction can predict cardiovascular outcomes in several populations of patients. The aim of this study was to assess the severity, time course, and clinical implications of endothelial dysfunction in patients with non-ST-segment elevation (NSTE) acute coronary syndromes (ACS). Sixty patients with NSTE ACS (mean age 62 ± 8 years, 44 men) and 40 controls with stable coronary artery disease (CAD) (mean age 63 ± 10 years, 27 men) were studied. In patients with NSTE ACS and in those with stable CAD, endothelial function was assessed <12 hours after admission and at 3-month follow-up by measuring right brachial artery dilation after 5 minutes of forearm ischemia (flow-mediated dilation [FMD]). Clinical outcomes were assessed after a median follow-up period of 32 months (range 14 to 36). The primary end point was a combination of cardiac death or readmission for new ACS or recurrence of angina pectoris. FMD on admission was significantly lower in patients with NSTE ACS compared to those with stable CAD (2.1 ± 1.2% vs 4.8 ± 1.9%, p <0.001). FMD improved significantly at 3-month follow-up in patients with NSTE ACS, becoming comparable to that in patients with stable CAD (5.7 ± 2.6% vs 5.5 ± 1.7%, p = 0.93). During follow-up, 14 cardiac events (23%) occurred in patients with NSTE ACS. On multivariate analysis, only diabetes (hazard ratio 18.1, 95% confidence interval 3.9 to 83.9, p <0.001) and FMD at 3 months (hazard ratio 0.78, 95% confidence interval 0.61 to 0.99, p = 0.04) were independent predictors of the primary end point in patients with NSTE ACS. In conclusion, endothelial function is markedly impaired in the acute phase of NSTE ACS but improves significantly at 3-month follow-up. In patients with NSTE ACS, FMD at 3 months after the acute event is a significant independent predictor of cardiac outcomes.

Adiponectin profile in Asian patients undergoing coronary revascularization and its association with plaque vulnerability: IDEAS-ADIPO study

Despite potent insulin-sensitizing, anti-inflammatory, and antiatherogenic effects in animal studies, the relationship between serum adiponectin level and coronary artery disease in patients remains unclear. We determined the adiponectin profile in a cohort of multiethnic Asian patients with coronary artery disease, and the association between serum adiponectin level and culprit lesion necrotic core (NC) content. Ninety-four Asian patients (BMI, 25.3 ± 3.7 kg/m(2)) undergoing percutaneous coronary intervention were recruited. The serum adiponectin level was measured (n = 94), and the baseline virtual histology intravascular ultrasound examination was analyzed (n = 88). The median level of adiponectin was 3.7 µg/ml (interquartile range, 2.8-4.5 µg/ml). The serum adiponectin level was below 10 µg/ml in 90 patients (95.7%) and below 6 µg/ml in 80 patients (85.1%). There was a significant association between ethnicity and serum adiponectin level (P = 0.048). The median adiponectin level was highest among the Chinese, followed by the Malay and the Indians. Serum adiponectin levels were positively associated with culprit lesion NC content. A 1-µg/ml increase in log adiponectin was associated with a 3.04% (95% confidence interval: 0.33-5.44) increase in culprit lesion NC content. This association remains significant after adjusting for age, sex, ethnicity, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and procedural indication. We found a low serum level of adiponectin in Asian patients and a significant ethnic effect on serum adiponectin level. Increased serum adiponectin levels were independently associated with increased culprit lesion NC burden, suggesting a role for adiponectin in modulating coronary plaque vulnerability.

Adiponectin induces pro-inflammatory programs in human macrophages and CD4+ T cells

Abundant experimental and clinical data support a modulatory role for adiponectin in inflammation, dysmetabolism, and disease. Because the activation of cells involved in innate and adaptive immunity contributes to the pathogenesis of diseases such as atherosclerosis and obesity, this study investigated the role of adiponectin in human macrophage polarization and T cell differentiation. Examination of the adiponectin-induced transcriptome in primary human macrophages revealed that adiponectin promotes neither classical (M1) nor alternative (M2) macrophage activation but elicits a pro-inflammatory response that resembles M1 more closely than M2. Addition of adiponectin to polyclonally activated CD4(+) T lymphocytes did not affect cell proliferation but induced mRNA expression and protein secretion of interferon (IFN)-γ and interleukin (IL)-6. Adiponectin treatment of CD4(+) T cells increased phosphorylation of p38 mitogen-activated protein kinase (MAPK) and signal transducer and activation of transcription (STAT) 4 and augmented T-bet expression. Inhibition of p38 with SB203580 abrogated adiponectin-induced IFN-γ production, indicating that adiponectin enhances T(H)1 differentiation through the activation of the p38-STAT4-T-bet axis. Collectively, our results demonstrate that adiponectin can induce pro-inflammatory functions in isolated macrophages and T cells, concurring with previous observations that adiponectin induces a limited program of inflammatory activation that likely desensitizes these cells to further pro-inflammatory stimuli.

Correlations between coronary plaque tissue composition assessed by virtual histology and blood levels of biomarkers for coronary artery disease

PURPOSE

We investigated correlations of coronary plaque composition determined by virtual histology (VH) intravascular ultrasound (IVUS) and blood levels of biomarkers that represent the vulnerability of coronary plaques.

MATERIALS AND METHODS

Pre- and postprocedural blood levels of high sensitivity C-reactive protein, soluble CD40 ligand (sCD40L), matrix metalloproteinase-9, and neopterin were measured in 70 patients with stable angina (SA) or unstable angina (UA) who were undergoing percutaneous coronary intervention (PCI) for single lesions. We evaluated the data for correlations between these biomarkers and necrotic core contents in PCI target lesions analyzed by VH.

RESULTS

Clinical characteristics, IVUS, VH, and biomarker blood levels were not different between the SA and the UA group except for more frequent previous statin use (52.3% vs. 23.1%, p=0.017) and lower remodeling index in the SA group (0.98±0.09 vs. 1.10±0.070, p<0.001). Among the biomarkers evaluated, only pre-PCI neopterin level showed a weakly significant correlation with the absolute volume of the necrotic core (r=0.320, p=0.008). Pre- and post-PCI blood levels of sCD40L (r=0.220, p=0.072; r=0.231, p=0.062) and post-PCI blood level of neopterin (r=0.238, p=0.051) showed trends toward weakly positive correlations with the absolute volume of necrotic core.

CONCLUSION

We found a weakly positive correlation between the pre-PCI neopterin level and necrotic core volume in the PCI-target lesion. The clinical implications of our findings need to be investigated in further studies.

Possible association between non-invasive parameter of flow-mediated dilatation in brachial artery and whole coronary plaque vulnerability in patients with coronary artery disease

BACKGROUND

Despite being a relatively widely-used non-invasive parameter of endothelial dysfunction, little is known regarding the relationship between flow-mediated dilatation (FMD) and coronary plaque vulnerability in patients with coronary artery disease (CAD).

METHODS

111 CAD patients (age; 68.9 ± 9.3) who underwent both coronary intervention and FMD were enrolled. Spectral analyses of intravascular ultrasound radiofrequency data for both culprit and non-culprit lesions were performed using Virtual Histology software. Plaque burden was described based on fibrotic, fibro-fatty, dense calcium, and necrotic core (NC) components, and thin-cap fibroatheroma (TCFA) was defined as focal NC rich (> 10%) plaques touching the lumen with a percent-plaque volume exceeding 40%.

RESULTS

Averaged %FMD was 2.86 ± 2.03% (median 2.27%, 25th 1.40%, 75th 4.20%). NC volumes were negatively correlated with log%FMD for both culprit and non-culprit lesions (P = 0.001, r = 0.31 and P = 0.03, r = 0.21, respectively). We divided the patients into three tertiles according to %FMD; 38 were lower (≤ 1.75%), 41 were middle (> 1.75%, but ≤ 3.5%), and 32 were upper tertile (> 3.5%). The prevalence rate of TCFA increased with decreasing %FMD tertile and the incidence of major adverse cardiac events was significantly higher in lower %FMD tertile. Multivariate logistic regression analyses showed that the most powerful predictive factor for TCFA was log%FMD (P < 0.0001), and ROC curve analysis identified %FMD of < 2.81% (AUC = 0.82, sensitivity: 91.2%, specificity: 66.7%) as the optimal cut-off point for predicting the presence of TCFA.

CONCLUSIONS

Impaired endothelial function in brachial arteries may be associated with whole coronary plaque vulnerability and poor clinical outcome in patients with CAD.

Randomized controlled trial for an effect of catechin-enriched green tea consumption on adiponectin and cardiovascular disease risk factors

Background

Previous observational studies have indicated that green tea (GT) consumption is associated with reduced mortality from cerebral infarction but not with mortality from cerebral hemorrhage. Therefore, we hypothesized that GT exerts a direct antiatherosclerotic effect without any effect on hypertension. To investigate this hypothesis, we focused on adiponectin that seems to be among the several key players in atherosclerosis.

Objective

The objective of this randomized controlled trial (RCT) was to assess whether the consumption of catechin-enriched GT affects serum adiponectin levels and cardiovascular disease (CVD) risk factors among apparently healthy subjects.

Design

A total of 51 individuals participated in the study. Eligible participants were randomly assigned into GT consumption groups with either high catechin (400 mg/day) or low catechin (100 mg/day). The study participants were asked to stop GT consumption for 2 weeks (washout period), following which they were to start drinking the provided GT beverages everyday for 9 weeks. The outcome measures were changes in the adiponectin levels and CVD risk factors (body weight, body mass index, waist circumference, blood pressure, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, fasting plasma glucose, as well as aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase, uric acid, and high-sensitive C-reactive protein).

Results

After intervention for 9 weeks, we found no significant difference between the high- and low catechin group with respect to changes in the serum adiponectin level: 0.35 µg/ml (95% confidence interval (CI): −1.03, 1.74). Also, no significant difference was observed between the high- and low catechin groups with respect to changes in any of the measured CVD risk factors.

Conclusion

This RCT showed no significant difference between the high- and low catechin groups with respect to changes in the serum adiponectin level and any CVD risk factors.

Metalloproteinases in metabolic syndrome

Experimental and clinical evidence supports the concept that metalloproteinases (MMPs), beyond different physiologic functions, also play a role in the development and rupture of the atherosclerotic plaque. Interest in MMPs has been rapidly increasing during the last years, especially as they have been proposed as biomarkers of vulnerable plaques. Different components of the metabolic syndrome (MS) have been identified as possible stimulus for the synthesis and activity of MMPs, like pro-inflammatory and pro-oxidant state, hyperglycemia, hypertension and dyslipidemia. On the other hand, anti-inflammatory cytokines like adiponectin are inversely associated with MMPs. Among the several MMPs studied, collagenases (MMP-1 and MMP-8) and gelatinases (MMP-2 and MMP-9) are the most associated with MS. Our aim was to summarize and discuss the relation between different components of the MS on MMPs, as well as the effect of the cluster of the metabolic alterations itself. It also highlights the necessity of further studies, in both animals and humans, to elucidate the function of novel MMPs identified, as well as the role of the known enzymes in different steps of metabolic diseases. Understanding the mechanisms of MS impact on MMPs and vice versa is an interesting area of research that will positively enhance our understanding of the complexity of MS and atherosclerosis.

Differential Characteristics of Inflammatory Responses to Stent Implantation Between De Novo and Intrastent Restenosis Lesion in Patients With Stable Angina

Mechanical plaque rupture of coronary atherosclerotic plaque during stent implantation can increase serum levels of high-sensitivity C-reactive protein (hsCRP). Patients with stable angina pectoris were divided into 2 groups: one group included 186 patients with de novo lesion who underwent stent implantation (de novo group); the other group included 40 patients with intrastent restenosis (ISR) undergoing stent implantation (ISR group). The de novo group had a significant increase in hsCRP levels post stenting, while the ISR group showed no increase in hsCRP post stenting. Intravascular ultrasound with radiofrequency data analysis showed that the de novo group had larger percentage of both necrotic core area and fibrofatty area at the target lesion than the ISR group, while the ISR group had a larger percentage of fibrous area. Differential inflammatory response to stent implantation between the de novo plaque and in ISR lesion is related to lesion morphology.

Prevalence of coronary artery calcium scores and silent myocardial ischaemia was similar in Indian Asians and European whites in a cross-sectional study of asymptomatic subjects from a U.K. population (LOLIPOP-IPC)

BACKGROUND

Coronary heart disease (CHD) mortality is 70% higher among Indian Asians (IA) than European whites (EW), the reasons for this excess remain unexplained. Coronary artery calcification (CAC) is highly correlated with coronary plaque burden and silent myocardial ischaemia in EW; but fails to identify excess risk in IA. We hypothesised that IA have a higher prevalence of silent myocardial ischaemia compared to EW, despite similar CAC, and this may explain their excess CHD mortality.

METHODS

CAC was measured for 2,369 asymptomatic men and women, aged 35 to 75 years, as part of the London Life Sciences Population (LOLIPOP) study. 518 subjects had CAC scores >100 Agatston units and of these 256 (49%) patients underwent myocardial perfusion scintigraphy (MPS).

RESULTS

CAC scores were similar among IA and EW, after adjustment for conventional risk factors. MPS abnormalities were seen in 56 (22%) subjects. Presence of diabetes (P = .03) and increasing CAC (P < .001) were independent predictors for severity of silent myocardial ischaemia. Ethnicity did not influence the prevalence or the extent of silent myocardial ischaemia.

CONCLUSION

MPS did not identify greater ischaemia among IA compared with EW. This appears incongruent with almost 2-fold higher risk of CHD mortality observed in IA.

Roles of the WHHL rabbit in translational research on hypercholesterolemia and cardiovascular diseases

Conquering cardiovascular diseases is one of the most important problems in human health. To overcome cardiovascular diseases, animal models have played important roles. Although the prevalence of genetically modified animals, particularly mice and rats, has contributed greatly to biomedical research, not all human diseases can be investigated in this way. In the study of cardiovascular diseases, mice and rats are inappropriate because of marked differences in lipoprotein metabolism, pathophysiological findings of atherosclerosis, and cardiac function. On the other hand, since lipoprotein metabolism and atherosclerotic lesions in rabbits closely resemble those in humans, several useful animal models for these diseases have been developed in rabbits. One of the most famous of these is the Watanabe heritable hyperlipidemic (WHHL) rabbit, which develops hypercholesterolemia and atherosclerosis spontaneously due to genetic and functional deficiencies of the low-density lipoprotein (LDL) receptor. The WHHL rabbit has been improved to develop myocardial infarction, and the new strain was designated the myocardial infarction-prone WHHL (WHHLMI) rabbit. This review summarizes the importance of selecting animal species for translational research in biomedical science, the development of WHHL and WHHLMI rabbits, their application to the development of hypocholesterolemic and/or antiatherosclerotic drugs, and future prospects regarding WHHL and WHHLMI rabbits.

Adiponectin and vulnerable atherosclerotic plaques

High-risk plaques that are vulnerable to rupture demonstrate distinct morphological characteristics. They are differentiated from the lesions responsible for stable coronary artery disease by their large necrotic cores, thin-inflamed fibrous caps, and positive remodeling. Adiponectin is an adipocytokine that is reduced in obesity and type 2 diabetes. Hypoadiponectinemia has been associated with an increased risk of coronary artery disease and acute coronary syndrome in several though not all studies. The involvement of adiponectin provides clues to the inflammatory and atherogenic mechanisms associated with pathological coronary disease progression.

Rosuvastatin, inflammation, C-reactive protein, JUPITER, and primary prevention of cardiovascular disease--a perspective

The major public health concern worldwide is coronary heart disease, with dyslipidemia as a major risk factor. Statin drugs are recommended by several guidelines for both primary and secondary prevention. Rosuvastatin has been widely accepted because of its efficacy, potency, and superior safety profile. Inflammation is involved in all phases of atherosclerosis, with the process beginning in early youth and advancing relentlessly for decades throughout life. C-reactive protein (CRP) is a well-studied, nonspecific marker of inflammation which may reflect general health risk. Considerable evidence suggests CRP is an independent predictor of future cardiovascular events, but direct involvement in atherosclerosis remains controversial. Rosuvastatin is a synthetic, hydrophilic statin with unique stereochemistry. A large proportion of patients achieve evidence-based lipid targets while using the drug, and it slows progression and induces regression of atherosclerotic coronary lesions. Rosuvastatin lowers CRP levels significantly. The Justification for Use of statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) trial was designed after the observation that when both low density lipoprotein and CRP were reduced, patients fared better than when only LDL was lowered. Advocates and critics alike acknowledge that the benefits of rosuvastatin in JUPITER were real. After a review, the US Food and Drug Administration extended the indications for rosuvastatin to include asymptomatic JUPITER-eligible individuals with one additional risk factor. The American Heart Association and Centers of Disease Control and Prevention had previously recognized the use of CRP in persons with "intermediate risk" as defined by global risk scores. The Canadian Cardiovascular Society guidelines went further and recommended use of statins in persons with low LDL and high CRP levels at intermediate risk. The JUPITER study focused attention on ostensibly healthy individuals with "normal" lipid profiles and high CRP values who benefited from statin therapy. The backdrop to JUPITER during this period was an increasing awareness of a rising cardiovascular risk burden and imperfect methods of risk evaluation, so that a significant number of individuals were being denied beneficial therapies. Other concerns have been a high level of residual risk in those who are treated, poor patient adherence, a need to follow guidelines more closely, a dual global epidemic of obesity and diabetes, and a progressively deteriorating level of physical activity in the population. Calls for new and more effective means of reducing risk for coronary heart disease are intensifying. In view of compelling evidence supporting earlier and aggressive therapy in people with high risk burdens, JUPITER simply offers another choice for stratification and earlier risk reduction in primary prevention patients. When indicated, and in individuals unwilling or unable to change their diet and lifestyles sufficiently, the benefits of statins greatly exceed the risks. Two side effects of interest are myotoxicity and an increase in the incidence of diabetes.

Adiponectin reduces C-reactive protein expression and downregulates STAT3 phosphorylation induced by IL-6 in HepG2 cells

By playing a direct proatherogenic role, C-reactive protein (CRP) is a potent independent predictor of future cardiovascular events. CRP is predominately synthesized by hepatocytes when stimulated by interleukin-6 (IL-6). In response to IL-6, the signal transducer and activator of transcription 3 (STAT3) becomes phosphorylated on tyrosine and serine residues. Phosphorylated STAT3 then activates CRP gene transcription. In obesity-related disorders such as diabetes, metabolic syndrome, and cardiovascular diseases, the circulating levels of CRP and adiponectin are inversely correlated, suggesting that these two factors might reciprocally regulate each other. We investigated the possibility that adiponectin inhibits CRP production in HepG(2) cells elicited by IL-6. CRP gene expression was determined using ELISA and semi-quantitative RT-PCR, and the phosphorylation of STAT3 was investigated with western blot. Adiponectin reduced IL-6-induced CRP mRNA levels in HepG(2) cells and CRP protein secretion. Preincubating HepG(2) cells with adiponectin led to a decline in STAT3 phosphorylation on both tyrosine and serine residues. Our results demonstrated that adiponectin suppresses CRP synthesis and secretion from HepG(2) cells and suggested that the suppression may be mediated through inhibition of the STAT3 pathway. The finding provides a novel insight into the molecular linkage between obesity and vascular diseases.

Clinical significance of inflammation factors in acute coronary syndrome from pathogenic toxin

The inflammation factors and roles of them in acute coronary syndrome (ACS) were explored. The similarity between the theory of pathogenic toxin in Chinese Medicine and the inflammation response theory in ACS was discussed. The exploration of new inflammatory factors may be helpful for Chinese Medicine in the research of ACS.

Adiponectin levels are associated with the number and activity of circulating endothelial progenitor cells in patients with coronary artery disease

OBJECTIVE

To study the relationship between plasma adiponectin concentration and the functional activities of circulating endothelial progenitor cells (EPCs) in patients with coronary artery disease (CAD).

METHODS

Circulating EPCs were enumerated as AC133(+)/KDR(+) cells via flow cytometry and identified by co-staining with DiI-acLDL and fluorescein isothiocyanate (FITC)-conjugated lectin under a fluorescent microscope. The migratory capacity of EPCs was measured by modified Boyden chamber assay. Adhesion capacity was performed to count adherent cells after replating EPCs on six-well culture dishes coated with fibronectin.

RESULTS

The number of circulating EPCs (AC133(+)/KDR(+) cells) decreased significantly in CAD patients, compared with control subjects [(74.2+/-12.3) vs (83.5+/-12.9) cells/ml blood, P<0.01]. In addition, the number of EPCs also decreased in CAD patients after ex vivo cultivation [(54.4+/-8.6) vs (71.9+/-11.6) EPCs/field, P<0.01]. Both circulating EPCs and differentiated EPCs were positively correlated with plasma adiponectin concentration. The functional activities of EPCs from CAD patients, such as migratory and adherent capacities, were also impaired, compared with control subjects, and positively correlated with plasma adiponectin concentration.

CONCLUSION

The study demonstrates that the impairment of the number and functional activities of EPCs in CAD patients is correlated with their lower plasma adiponectin concentrations.

Low adiponectin levels are an independent predictor of mixed and non-calcified coronary atherosclerotic plaques

Background

Atherosclerosis is the primary cause of coronary artery disease (CAD). There is increasing recognition that lesion composition rather than size determines the acute complications of atherosclerotic disease. Low serum adiponectin levels were reported to be associated with coronary artery disease and future incidence of acute coronary syndrome (ACS). The impact of adiponectin on lesion composition still remains to be determined.

Methodology/Principal Findings

We measured serum adiponectin levels in 303 patients with stable typical or atypical chest pain, who underwent dual-source multi-slice CT-angiography to exclude coronary artery stenosis. Atherosclerotic plaques were classified as calcified, mixed or non-calcified. In bivariate analysis adiponectin levels were inversely correlated with total coronary plaque burden (r = −0.21, p = 0.0004), mixed (r = −0.20, p = 0.0007) and non-calcified plaques (r = −0.18, p = 0.003). No correlation was seen with calcified plaques (r = −0.05, p = 0.39). In a fully adjusted multivariate model adiponectin levels remained predictive of total plaque burden (estimate: −0.036, 95%CI: −0.052 to −0.020, p<0.0001), mixed (estimate: −0.087, 95%CI: −0.132 to −0.042, p = 0.0001) and non-calcified plaques (estimate: −0.076, 95%CI: −0.115 to −0.038, p = 0.0001). Adiponectin levels were not associated with calcified plaques (estimate: −0.021, 95% CI: −0.043 to −0.001, p = 0.06). Since the majority of coronary plaques was calcified, adiponectin levels account for only 3% of the variability in total plaque number. In contrast, adiponectin accounts for approximately 20% of the variability in mixed and non-calcified plaque burden.

Conclusions/Significance

Adiponectin levels predict mixed and non-calcified coronary atherosclerotic plaque burden. Low adiponectin levels may contribute to coronary plaque vulnerability and may thus play a role in the pathophysiology of ACS.

Pioglitazone reduces the necrotic-core component in coronary plaque in association with enhanced plasma adiponectin in patients with type 2 diabetes mellitus

BACKGROUND

Pioglitazone has a preventive effect on cardiovascular disease, but its ability to stabilize coronary plaque is unknown.

METHODS AND RESULTS

A prospective, randomized trial was conducted in 54 patients with type 2 diabetes and stable angina pectoris, randomly assigned to either a pioglitazone group or control group. Non-culprit, angiographically mild-to-moderate obstructive lesions were examined with virtual histology intravascular ultrasound (VH-IVUS) at coronary intervention and 6 months later. In total, 42 lesions of 22 patients in the pioglitazone group and 44 lesions of 24 patients in the control group were analyzed. After 6 months, patients in the pioglitazone group had significantly improved blood sugar, high-sensitivity C-reactive protein, and plasma adiponectin levels. VH-IVUS analysis revealed that, although the total plaque-to-vessel volume was not changed in either group, the necrotic-core area had significantly decreased in the pioglitazone group (-4.6+/-5.9% vs 1.1+/-9.3%, P=0.001). There was a significant inverse correlation between the change in plasma adiponectin levels and the change in necrotic-core area (r=-0.46, P<0.0001).

CONCLUSIONS

Pioglitazone may stabilize coronary plaque by reducing the necrotic-core component, in association with enhanced plasma adiponectin levels.

Unstable coronary plaques and cardiac events in myocardial infarction-prone Watanabe heritable hyperlipidemic rabbits: questions and quandaries

PURPOSE OF REVIEW

Use of suitable animal models is essential for investigation of the mechanisms underlying cardiac events and development of the therapeutic strategies; however, ideal animal models that can recapitulate human coronary atherosclerosis and subsequent acute myocardial infarction are still lacking. In this article, we review the insights learned from myocardial infarction-prone Watanabe heritable hyperlipidemic (designated as WHHLMI) rabbits and discuss the possibility of using this model for the study of human acute coronary syndromes.

RECENT FINDINGS

The vulnerable plaques of human coronary arteries are histologically characterized by a large lipid core and a thin fibrous cap with inflammatory cells. Recent studies have revealed that inflammatory cells and inflammatory mediators (such as cytokines and matrix metalloproteinases) play an important role in the plaque rupture.

SUMMARY

We developed the WHHLMI rabbit that shows spontaneous myocardial infarction caused by coronary atherosclerosis. The coronary lesions of WHHLMI rabbits have features of fatty streaks, fibrous plaques, and fibroatheromatous plaques. Some plaques contain a lipid core and a thin fibrous cap similar to human vulnerable plaques. In spite of this, the plaque rupture is not observed in WHHLMI rabbits, suggesting that other additional factors such as mechanical stress are required to trigger the rupture. WHHLMI rabbits may become an important means for elucidating the possible mechanisms of plaque rupture by exposing the plaques to additional risk factors beyond hyperlipidemia.