Circulating malondialdehyde-modified low-density lipoprotein levels are associated with the presence of thin-cap fibroatheromas determined by optical coherence tomography in coronary artery disease

Hepatic steatosis evidenced by computed tomography in patients undergoing primary percutaneous coronary intervention for acute myocardial infarction

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) and acute myocardial infarction (AMI) have common pathological links. This study investigates the prognostic impact of NAFLD assessed as hepatic steatosis (HS) by computed tomography (CT) in AMI patients and explores the mechanistic role of NAFLD in cardiovascular (CV) events using coronary angioscopy (CAS).

METHODS

We retrospectively examined 342 AMI patients who underwent CT followed by primary percutaneous coronary intervention (PCI) between January 2014 and December 2019. HS was defined as a hepatic to spleen attenuation ratio of <1.0 on CT scans. Major cardiac events (MCE) included cardiac death, non-fatal myocardial infarction, target-vessel revascularization, and target-lesion revascularization.

RESULTS

HS was identified in 88 patients (26 %). Patients with HS were significantly younger, had a higher body mass index, and higher hemoglobin A1c, triglyceride, and malondialdehyde low-density lipoprotein levels (all p < 0.05). MCE occurred more frequently [27 (30.7 %) vs. 39 (15.4 %), p = 0.001] in the HS group than in the non-HS group. In the multivariate analysis, the presence of HS was an independent predictor of MCE after adjusting for metabolic risk factor and liver function markers. Among the 74 patients who underwent CAS for a median of 15 days after primary PCI, 51 (69 %) had intrastent thrombus, which was strongly associated with the presence of HS [18 (35 %) vs. 1 (4 %), p = 0.005].

CONCLUSIONS

AMI patients with NAFLD detected by CT often had CAS-derived intrastent thrombi and were at a high risk for CV events. Therefore, these patients should be carefully monitored.

Novel Therapeutic Approaches to Prevent Atherothrombotic Ischemic Stroke in Patients with Carotid Atherosclerosis

Atherothrombotic stroke represents approximately 20% of all ischemic strokes. It is caused by large-artery atherosclerosis, mostly in the internal carotid artery, and it is associated with a high risk of early recurrence. After an ischemic stroke, tissue plasminogen activator is used in clinical practice, although it is not possible in all patients. In severe clinical situations, such as high carotid stenosis (≥70%), revascularization by carotid endarterectomy or by stent placement is carried out to avoid recurrences. In stroke prevention, the pharmacological recommendations are based on antithrombotic, lipid-lowering, and antihypertensive therapy. Inflammation is a promising target in stroke prevention, particularly in ischemic strokes associated with atherosclerosis. However, the use of anti-inflammatory strategies has been scarcely studied. No clinical trials are clearly successful and most preclinical studies are focused on protection after a stroke. The present review describes novel therapies addressed to counteract inflammation in the prevention of the first-ever or recurrent stroke. The putative clinical use of broad-spectrum and specific anti-inflammatory drugs, such as monoclonal antibodies and microRNAs (miRNAs) as regulators of atherosclerosis, will be outlined. Further studies are necessary to ascertain which patients may benefit from anti-inflammatory agents and how.

Comparison of moderate-intensity continuous training and high-intensity interval training effects on the Ido1-KYN-Ahr axis in the heart tissue of rats with occlusion of the left anterior descending artery

Myocardial infarction (MI) affects many molecular pathways in heart cells, including the Ido1-KYN-Ahr axis. This pathway has recently been introduced as a valuable therapeutic target in infarction. We examined the effects of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on the axis in the heart tissue of male Wistar rats with occluded left anterior descending (OLAD). Thirty rats (age 10-12 weeks, mean weight 275 ± 25 g) were divided into five groups with 6 animals: Control (Ct) group, MICT group, rats with OLAD as MI group, rats with OLAD treated with MICT (MIMCT group) and rats with OLAD treated with HIIT (MIHIIT group). Rats performed the training protocols for 8 weeks, 5 days a week. HIIT included 7 sets of 4 min running with an intensity of 85-90% VO₂max and 3 min of recovery activation between sets. MICT included continuous running at the same distance as HIIT with an intensity of 50-60% VO₂max for 50 min. The expressions of Ahr, Cyp1a1, and Ido1 were assayed by real-time PCR. Malondialdehyde (MDA) and Kynurenine levels, and AHR, CYP1A1, and IDO1 proteins were detected using ELISA. Data were analyzed using the ANOVA and MANOVA tests. Compared to the CT group, MI caused an increase in all studied factors, but only statistically significant (P < 0.05) for MDA and IDO1. With a greater effect of HIIT, both protocols significantly lowered the proteins expressions in the MIHIIT and MIMCT groups, compared with the MI group (P < 0.001). In healthy rats, only AHR protein significantly decreased in the MICT group compared to the Ct group (P < 0.05). HIIT and MICT protocols significantly reduced the gene and protein expression of Cyp1a1 (P < 0.05) and Ido1 (P < 0.01), and HIIT had a greater effect. In conclusion, both protocols were effective at reducing the levels of Ido1-Kyn-Ahr axis components and oxidative stress in the infarcted heart tissue and HIIT had a higher significant effect.

Electronegative LDL Is Associated with Plaque Vulnerability in Patients with Ischemic Stroke and Carotid Atherosclerosis

Owing to the high risk of recurrence, identifying indicators of carotid plaque vulnerability in atherothrombotic ischemic stroke is essential. In this study, we aimed to identify modified LDLs and antioxidant enzymes associated with plaque vulnerability in plasma from patients with a recent ischemic stroke and carotid atherosclerosis. Patients underwent an ultrasound, a CT-angiography, and an ¹⁸F-FDG PET. A blood sample was obtained from patients (n = 64, 57.8% with stenosis ≥50%) and healthy controls (n = 24). Compared to the controls, patients showed lower levels of total cholesterol, LDL cholesterol, HDL cholesterol, apolipoprotein B (apoB), apoA-I, apoA-II, and apoE, and higher levels of apoJ. Patients showed lower platelet-activating factor acetylhydrolase (PAF-AH) and paraoxonase-1 (PON-1) enzymatic activities in HDL, and higher plasma levels of oxidized LDL (oxLDL) and electronegative LDL (LDL(-)). The only difference between patients with stenosis ≥50% and <50% was the proportion of LDL(-). In a multivariable logistic regression analysis, the levels of LDL(-), but not of oxLDL, were independently associated with the degree of carotid stenosis (OR: 5.40, CI: 1.15-25.44, p < 0.033), the presence of hypoechoic plaque (OR: 7.52, CI: 1.26-44.83, p < 0.027), and of diffuse neovessels (OR: 10.77, CI: 1.21-95.93, p < 0.033), indicating that an increased proportion of LDL(-) is associated with vulnerable atherosclerotic plaque.

Atherogenic Lipoproteins for the Statin Residual Cardiovascular Disease Risk

Randomized controlled trials (RCTs) show that decreases in low-density lipoprotein cholesterol (LDL-C) by the use of statins cause a significant reduction in the development of cardiovascular disease (CVD). However, one of our previous studies showed that, among eight RCTs that investigated the effect of statins vs. a placebo on CVD development, 56–79% of patients had residual CVD risk after the trials. In three RCTs that investigated the effect of a high dose vs. a usual dose of statins on CVD development, 78–87% of patients in the high-dose statin arms still had residual CVD risk. The risk of CVD development remains even when statins are used to strongly reduce LDL-C, and this type of risk is now regarded as statin residual CVD risk. Our study shows that elevated triglyceride (TG) levels, reduced high-density lipoprotein cholesterol (HDL-C), and the existence of obesity/insulin resistance and diabetes may be important metabolic factors that determine statin residual CVD risk. Here, we discuss atherogenic lipoproteins that were not investigated in such RCTs, such as lipoprotein (a) (Lp(a)), remnant lipoproteins, malondialdehyde-modified LDL (MDA-LDL), and small-dense LDL (Sd-LDL). Lp(a) is under strong genetic control by apolipoprotein (a), which is an LPA gene locus. Variations in the LPA gene account for 91% of the variability in the plasma concentration of Lp(a). A meta-analysis showed that genetic variations at the LPA locus are associated with CVD events during statin therapy, independent of the extent of LDL lowering, providing support for exploring strategies targeting circulating concentrations of Lp(a) to reduce CVD events in patients receiving statins. Remnant lipoproteins and small-dense LDL are highly associated with high TG levels, low HDL-C, and obesity/insulin resistance. MDA-LDL is a representative form of oxidized LDL and plays important roles in the formation and development of the primary lesions of atherosclerosis. MDA-LDL levels were higher in CVD patients and diabetic patients than in the control subjects. Furthermore, we demonstrated the atherogenic properties of such lipoproteins and their association with CVD as well as therapeutic approaches.

Cardioprotective Effect of Acetylsalicylic Acid in the Myocardial Ischemia-Reperfusion Model on Oxidative Stress Markers Levels in Heart Muscle and Serum

Heart failure occurs in increased oxidative stress conditions, which contribute to the progression of pathological changes. Orally or intravenously administered acetylsalicylic acid (ASA, aspirin) is typically used in human patients with acute myocardial ischemia. The study used an experimental porcine ischemia-reperfusion model to evaluate the potential cardioprotective effect of intracoronary administered ASA on myocardial ischemia-reperfusion injury. The cardioprotective effect of ASA was evaluated by measuring selected oxidative stress markers levels in infarcted and non-infarcted myocardium 14 days after the procedure, and three times in serum, before the procedure, during the reperfusion process, and after 14-day recovery. The results showed that intracoronary administrated ASA reduced the oxidative stress. The level of oxidative stress, measured with the non-enzymatic markers total antioxidant capacity (TAC), total oxidative status (TOS), and malondialdehyde (MDA), and the enzymatic markers glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST), in heart tissue was significantly higher in a control group injected with saline. The level of oxidative stress in serum, measured with TAC, TOS, oxidative stress index (OSI), and lipofuscin (LF), was also higher in the control group than in animals injected with ASA. The confirmed cardioprotective effect of intracoronary administered ASA provides the foundation for further studies on ASA intracoronary application, which may lead to the development of a new therapy for the treatment of ischemia-reperfusion complications in humans.

The Potential Mediating Effects of Inflammation on the Association Between Type D Personality and Coronary Plaque Vulnerability in Patients With Coronary Artery Disease: An Optical Coherence Tomography Study

OBJECTIVE

Type D personality involves the interaction between negative affectivity with social inhibition and has been associated with an increased risk of coronary artery disease (CAD) progression and coronary plaque vulnerability. However, the underlying mechanisms in the relationship between type D personality and coronary plaque vulnerability remain indeterminate. The present study examined the potential mediating effects of inflammation biomarkers on the association between type D personality and coronary plaque vulnerability in patients with CAD.

METHODS

A total of 347 patients (mean [standard deviation] age = 56.6 [11.2] years; 29.3% women) with CAD who had culprit coronary plaques were examined for type D personality. The inflammation biomarkers (high-sensitivity C-reactive protein, interleukin 6 [IL-6], and tumor necrosis factor α [TNF-α]) were evaluated. Each individual inflammation biomarker was standardized using z scores to calculate inflammation standardized sumscores. Plaque vulnerability of culprit lesions was measured in vivo using optical coherence tomography.

RESULTS

The presence of type D personality (38%) was associated with TNF-α, IL-6, and inflammation standardized sumscores (t = 2.74, Cohen d = 0.32, p = .006; t = 4.03, Cohen d = 0.44, p ≤. 001; t = 4.16, Cohen d = 0.11, p = .001, respectively). In addition, the standardized inflammation sumscore was a mediator of the relationship between type D personality and lipid-rich plaques (effect sizes = 0.12, 95% confidence interval = 0.007-0.286, p = .064) and plaque rupture vulnerability (effect sizes = 0.16, 95% confidence interval = 0.043-0.365, p = .024). Analysis of continuous type D scores revealed that TNF-α, IL-6, and inflammation standardized sumscores also mediate the relationship between the primary effect of negative affectivity and plaque vulnerability.

CONCLUSIONS

Inflammation activation is a potential mediator of the association between type D personality and plaque vulnerability. The negative affectivity component of type D personality might be particularly relevant to the inflammatory aspects of plaque vulnerability.

Statins and Inflammation

PURPOSE OF REVIEW

Chronic inflammation has been recognized as one of the most important pathophysiological mechanisms' initiation and progression of atherosclerosis. Statins belong to most successful therapeutic agents in the prevention and treatment of atherothrombotic vascular disease. Their non-lipid related effects including suppression of inflammation have been repeatedly proven in both experimental and clinical settings.

RECENT FINDINGS

Recently, the importance of inflammation in the process of atherosclerosis has been confirmed by interventions targeting inflammation selectively. Clinical trial with selective inhibitor of a principal inflammatory mediator interleukin 1-beta - canakinumab - confirmed the notion of direct vasculoprotective effects of primarily targeting inflammation. This has increased interest in the non-lipid, pleiotropic and, particularly, anti-inflammatory effects of statins. Anti-inflammatory effects of statins have been proven both experimentally and in clinical settings beyond any doubt. They comprise a direct positive effect on not only many cell types and pathways that are lipid independent but, also, some that are mediated by lipid modification. Undoubtedly, suppression of inflammatory response by statins contributes to their generally positive action in atherosclerosis and represents an important part of the vasculo- and atheroprotective effect of this drug class.

Additional Effect of Coronary High-Intensity Plaque on T1-Weighted Magnetic Resonance Imaging With Circulating Malondialdehyde-Modified Low-Density Lipoprotein on Cardiac Events

BACKGROUND

Although elevated levels of oxidized low-density lipoprotein (LDL) could play a critical role in vulnerable plaque, there are no studies that have compared coronary high-intensity plaque (HIP) and circulating malondialdehyde-modified (MDA)-LDL levels for the prediction of cardiac events.

METHODS AND RESULTS

A total of 139 patients with coronary artery stenosis (>70%) were examined with non-contrast T1-weighted magnetic resonance imaging (MRI) (HIP: n=64, non-HIP: n=75). Scheduled percutaneous coronary intervention (PCI) for culprit lesions was performed within 48 h after MRI. HIP was defined as a signal intensity of coronary plaque to cardiac muscle ratio (PMR) ≥1.4. We evaluated the subsequent major adverse cardiac events (MACE) during the follow-up period (5.6±1.3 years). MDA-LDL levels were independently associated with the presence of HIP (P<0.0001). The incidence of MACE was 15%, and it was significantly higher in patients with HIP (27%) than in those without HIP (5%; P=0.011). Cox proportional hazard analysis showed MDA-LDL levels (P=0.007) and PMR (P=0.016) were significantly associated with MACE. For MACE prediction, C-statistic values for MDA-LDL, PMR, and PMR+MDA-LDL were 0.724, 0.791, and 0.800, respectively. Compared with MDA-LDL alone, the addition of PMR to MDA-LDL increased net reclassification improvement by 0.78 (P=0.012).

CONCLUSIONS

MDA-LDL levels might be associated with the presence of HIP in patients with coronary artery disease. Furthermore, adding PMR to MDA-LDL levels markedly improved prediction of subsequent MACE after PCI.

Clinical relevance of nitrated beta 2-glycoprotein I in antiphospholipid syndrome: Implications for thrombosis risk

Β₂-Glycoprotein I (β₂GPI) is an important anti-thrombotic protein and is the major auto-antigen in the antiphospholipid syndrome (APS). The clinical relevance of nitrosative stress in post translational modification of β₂GPI was examined.The effects of nitrated (n)β₂GPI on its anti-thrombotic properties and its plasma levels in primary and secondary APS were determined with appropriate clinical control groups. β2-glycoprotein I was nitrated at tyrosines 218, 275 and 309. β₂-glycoprotein I binds to lipid peroxidation modified products through Domains IV and V. Nitrated β₂GPI loses this binding (p < 0.05) and had diminished activity in inhibiting platelet adhesion to vWF under high shear flow (p < 0.01). Levels of nβ₂GPI were increased in patients with primary APS compared to patients with either secondary APS (p < 0.05), autoimmune disease without APS (p < 0.05) or non-autoimmune patients with arterial thrombosis (p < 0.01) and healthy individuals (p < 0.05).In conclusion tyrosine nitration of plasma β₂GPI is demonstrated and has important implications with regards to the pathophysiology of platelet mediated thrombosis in APS. Elevated plasma levels of nβ₂GPI in primary APS may be a risk factor for thrombosis warranting further investigation.

Increased Circulating Malondialdehyde-Modified Low-Density Lipoprotein Level Is Associated with High-Risk Plaque in Coronary Computed Tomography Angiography in Patients Receiving Statin Therapy

Objective: To evaluate the association of serum malondialdehyde low-density lipoprotein (MDA-LDL), an oxidatively modified LDL, with the prevalence of high-risk plaques (HRP) determined with coronary computed tomography angiography (CTA) in statin-treated patients. Methods: This study was a single-center retrospective cohort comprising 268 patients (mean age 67 years, 58% men) with statin therapy and who underwent coronary CTA for suspected stable coronary artery disease. Patients were classified into two groups according to median MDA-LDL level or median LDL-C level. Coronary CTA-verified HRP was defined when two or more characteristics, including positive remodeling, low-density plaques, and spotty calcification, were present. Results: Patients with HRP had higher MDA-LDL (p = 0.011), but not LDL-C (p = 0.867) than those without HRP. High MDA-LDL was independently associated with HRP (odds ratio 1.883, 95% confidential interval 1.082–3.279) after adjustment for traditional risk factors. Regarding incremental value of MDA-LDL for predicting CTA-verified HRP, addition of serum MDA-LDL levels to the baseline model significantly increased global chi-square score from 26.1 to 32.8 (p = 0.010). Conclusions: A high serum MDA-LDL level is an independent predictor of CTA-verified HRP, which can lead to cardiovascular events in statin-treated patients.

Oxidised LDL and Anti-Oxidised LDL Antibodies Are Reduced by Lipoprotein Apheresis in a Randomised Controlled Trial on Patients with Refractory Angina and Elevated Lipoprotein(a)

Aims: An abundance of epidemiological evidence demonstrates that elevated lipoprotein(a) (Lp(a)) represents a significant contributing risk factor towards the development of cardiovascular disease. In particular, raised Lp(a) may play a mechanistic role in patients with refractory angina. Studies have also shown a correlation between oxidised LDL (oxLDL) levels and atherosclerotic burden as well as rates of cardiovascular events. Antibodies against oxLDL (anti-oxLDL) are involved in the removal of oxLDL. Lipoprotein apheresis (LA), which removes lipoproteins using extra-corporeal processes, is an established means of reducing Lp(a), and thereby reduces cardiovascular events. The aim of this study was to investigate the effect of LA on oxLDL and anti-oxLDL levels amongst those with refractory angina in the context of raised Lp(a). Methods: We performed a sub-study within a randomised controlled crossover trial involving 20 patients with refractory angina and raised Lp(a) > 500 mg/L, comparing the effect of three months of blinded weekly LA or sham, followed by crossover to the opposite study arm. We utilized enzyme-linked immunosorbent assays (ELISA) to quantify oxLDL and IgG/ IgM anti-oxLDL antibody levels at baseline and following three months of active LA or sham sessions. Results: Following three months of LA, there was a 30% reduction in oxLDL from 0.37 ± 0.06 to 0.26 ± 0.04 with a mean drop of -0.11 units (U) (95% CI -0.13, -0.09) compared to no significant change with sham therapy (p < 0.0001 between treatment arms). LA also led to a 22% reduction in levels of IgG and IgM anti-oxLDL, again with no significant change demonstrated during sham (p = 0.0036 and p = 0.012, respectively, between treatment arms). Conclusion: Amongst patients with refractory angina in the context of elevated Lp(a), LA significantly lowers levels of oxLDL and anti-oxLDL antibodies, representing potential mechanisms by which LA yields symptomatic and prognostic benefits in this patient cohort.

Oxidants and antioxidants in myocardial infarction (MI): Investigation of ischemia modified albumin, malondialdehyde, superoxide dismutase and catalase in individuals diagnosed with ST elevated myocardial infarction (STEMI) and non-STEMI (NSTEMI)

Background

Coronary ischemia can lead to myocardial damage and necrosis. The pathogenesis of cardiovascular diseases often includes increased oxidative stress and decreased antioxidant defense. The study aimed to assess levels of ischemia modified albumin (IMA), malondialdehyde acid (MDA), superoxide dismutase (SOD), and catalase in individuals diagnosed with ST elevated myocardial infarction (STEMI) and non-STEMI.

Methods

The present study prospectively included 50 STEMI patients, 55 NSTEMI patients, and 55 healthy subjects. Only patients who were recently diagnosed with STEMI or NSTEMI were included in this study. IMA, MDA, SOD, and catalase activities were measured spectrophotometrically. Significant coronary artery lesions were determined by angiography.

Results

Patients with ACS had significantly greater IMA and MDA values than the healthy controls (p<0.001). Besides, patients with STEMI had IMA levels that were significantly greater than those of the patients with NSTEMI (p<0.001), while the reverse was true for MDA levels (p<0.001). The healthy controls had the highest levels of SOD and catalase levels, followed by patients with STEMI and patients with NSTEMI, respectively (p<0.001). There was a significant negative correlation among MDA and SOD with catalase levels (r = -0.771 p<0.001 MDA vs catalase; r = -0.821 p<0.001 SOD vs catalase).

Conclusions

Data obtained in this study reveals that compared to healthy controls, STEMI and NSTEMI patients had increased levels of MDA and IMA and decreased levels of SOD and catalase.

Natural products: The role and mechanism in low-density lipoprotein oxidation and atherosclerosis

Atherosclerosis is a chronic inflammatory, metabolic, and epigenetic disease, which leads to the life-threatening coronary artery disease. Emerging studies from bench to bedside have demonstrated the pivotal role of low-density lipoprotein (LDL) oxidation in the initiation and progression of atherosclerosis. This article hereby reviews oxidation mechanism of LDL, and the pro-atherogenic and biomarker role of oxidized LDL in atherosclerosis. We also review the pharmacological effects of several representative natural products (vitamin E, resveratrol, quercetin, probucol, tanshinone IIA, epigallocatechin gallate, and Lycopene) in protecting against LDL oxidation and atherosclerosis. Clinical and basic research supports the beneficial effects of these natural products in inhibiting LDL oxidation and preventing atherosclerosis, but the data are still controversial. This may be related to factors such as the population and the dosage and time of taking natural products involved in different studies. Understanding the mechanism of LDL oxidation and effect of oxidized LDL help researchers to find novel therapies against atherosclerosis.

Impact of malondialdehyde-modified low-density lipoprotein on clinical outcomes after fractional flow reserve-guided deferral of revascularization

Cardiovascular events can occur after deferred revascularization, and malondialdehyde-modified low-density lipoprotein (MDA-LDL) has been suggested to be an atherogenic marker. We investigated the relationship between serum MDA-LDL levels and clinical outcomes in patients with fractional flow reserve (FFR)-guided deferral of revascularization. Among 3084 patients undergoing coronary angiography, we retrospectively analyzed 127 patients with intermediate stenosis and deferred revascularization based on FFR > 0.80. Median follow-up interval was 30.4 months, and serum MDA-LDL was measured prior to the measurement of FFR. We evaluated the composite of major adverse cardiac events (MACEs), including cardiac death, myocardial infarction, ischemia-driven deferred lesion revascularization, and any revascularization. MACEs occurred in 18 (14.2%) patients. The MACE group presented with significantly higher MDA-LDL levels than the non-MACE group (134.9 ± 33.3 U/L vs. 95.6 ± 32.2 U/L, P < 0.001). In analysis of the receiver operating characteristics curve for the prediction of MACEs, MDA-LDL presented a significantly larger area under the curve than low-density lipoprotein-cholesterol (LDL-C; 0.810 vs. 0.687, P = 0.042). Univariate Cox regression analysis indicated a significant relationship between MACEs and MDA-LDL (per 10 U/L, HR 1.20; P = 0.004), as did the multivariate model (per 10 U/L, HR 1.17; P = 0.019). When compared according to the median LDL-C (98 mg/dL), the MACE group had significantly higher MDA-LDL in both the high (147.2 ± 27.3 U/L vs. 113.9 ± 31.2 U/L, P = 0.001) and low (103.2 ± 27.3 U/L vs. 80.2 ± 24.0 U/L, P = 0.045) LDL-C groups. Serum MDA-LDL levels were associated with cardiac events in patients with deferral of revascularization based on FFR.

Association of systemic inflammatory biomarkers with morphological characteristics of coronary atherosclerotic plaque by intravascular optical coherence tomography

Despite significant advances in preventive, medical, and interventional management, coronary artery disease remains the leading cause of death worldwide. We now know that in the majority of acute coronary syndromes, a thrombotic event is triggered either by the rupture or erosion of the so-called high-risk or 'vulnerable' plaque. However, accurately identifying the individual who is at significant risk of acute event remains the holy grail of preventive cardiology. To better stratify an individual's risk of developing and suffering a cardiovascular event, biomarkers are needed that can accurately predict coronary events and, if possible, monitor disease activity in response to medical or interventional therapies. In order to be able to understand the association of these biomarkers with the morphological substrate of high-risk plaques, intravascular imaging modalities can provide invaluable assistance. Novel imaging tools such as optical coherence tomography (OCT) have not only helped in identifying atherosclerotic plaque characteristics that are unstable but also in estimating global plaque burden. In this study, we provide an overview of our current knowledge of association of various inflammatory markers with atherosclerotic plaque characteristics seen on OCT.

Serum malondialdehyde-modified low-density lipoprotein levels on admission predict prognosis in patients with acute coronary syndrome undergoing percutaneous coronary intervention

BACKGROUND

Malondialdehyde-modified low-density lipoprotein (MDA-LDL) is a predictive marker of cardiovascular events in patients with stable angina pectoris. However, little is known about this marker in patients with acute coronary syndrome (ACS). We investigated the prognostic relevance of MDA-LDL to cardiovascular outcomes in patients with ACS.

METHODS

A total of 370 consecutive patients with ACS who underwent primary percutaneous coronary intervention (PCI) were enrolled from October 2009 to September 2014 at Mitoyo General Hospital. Serum MDA-LDL levels were measured at admission. The patients were divided into three tertile groups according to serum MDA-LDL levels. The primary outcomes were cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, revascularization, and heart failure requiring hospital admission.

RESULTS

MDA-LDL levels in patients with acute myocardial infarction were significantly greater than those in patients with unstable angina pectoris (mean±standard deviation: 133±48U/L vs. 157±69U/L, p=0.001). During follow-up [472 (195-920) days], 82 (22%) events occurred. Kaplan-Meier analysis showed that patients in the highest MDA-LDL tertile had the worst prognosis (log-rank, p<0.001). Cox regression analysis showed that serum MDA-LDL levels were an independent predictor of cardiovascular events after PCI in patients with ACS, even after adjustment for age, sex, body mass index, conventional cardiovascular risk factors, other lipid biomarkers, statin use on admission, cardiac biomarkers, and presence or absence of multivessel disease (hazard ratio: 1.80 per 1 standard deviation U/L increase, 95% confidence interval: 1.07-3.16, p=0.027).

CONCLUSION

Serum MDA-LDL levels on admission are a significant prognostic marker in patients with ACS who undergo successful PCI.

Oxidized LDL and anti-oxidized LDL antibodies in atherosclerosis - Novel insights and future directions in diagnosis and therapy<sup/>

We provide an up-to-date overview of current topics surrounding oxidized low-density lipoprotein (oxLDL) and its related antibodies in the quest to better identify the individuals at risk of cardiovascular disease and atherosclerotic plaques with unfavorable characteristics. We discuss the potential of oxLDL and anti-oxLDL antibodies as serum biomarkers of cardiovascular disease and emerging studies examining the targeting of arterial oxLDL for imaging and therapeutic delivery.

Type D personality and coronary atherosclerotic plaque vulnerability: The potential mediating effect of health behavior

OBJECTIVE

The association between type D personality and coronary plaque vulnerability has been suggested. The objective of the study was to evaluate the potential mediating effects of health behavior on the association between type D personality and plaque vulnerability in coronary artery disease (CAD) patients.

METHODS

A total of 319 CAD patients were assessed for type D personality and health behavior via self-administered questionnaires. The plaque vulnerability, evaluated according to characteristics, accompaniment, and outcomes of plaque, was assessed by optical coherence tomography.

RESULTS

Regression analysis showed that type D personality was independently associated with lipid plaque (odds ratio [OR] = 2.387, p = 0.001), thin cap fibroatheroma (TCFA) (OR = 2.366, p = 0.001), rupture (OR = 2.153, p = 0.002), and lipid arc (β = -0.291, p < 0.001). Mediation analyses showed that aspects of health behavior were significant mediators of the relationship between type D personality and plaque vulnerability. Psychological stress mediated the relationship between type D and lipid plaque (p = 0.030), TCFA (p = 0.034), and rupture (p = 0.013). Living habits significantly mediated the relationship between type D and lipid plaque (p = 0.028), TCFA (p = 0.036), but not rupture (p = 0.066). Participating in activities was not a significant mediator of the relationship between type D personality and lipid plaque (p = 0.115), TCFA (p = 0.115), or rupture (p = 0.077).

CONCLUSIONS

Health behaviors (psychological stress and living habits) may be mediators of the association between type D personality and plaque vulnerability.

Oxidative Stress in Human Atherothrombosis: Sources, Markers and Therapeutic Targets

Atherothrombosis remains one of the main causes of morbidity and mortality worldwide. The underlying pathology is a chronic pathological vascular remodeling of the arterial wall involving several pathways, including oxidative stress. Cellular and animal studies have provided compelling evidence of the direct role of oxidative stress in atherothrombosis, but such a relationship is not clearly established in humans and, to date, clinical trials on the possible beneficial effects of antioxidant therapy have provided equivocal results. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is one of the main sources of reactive oxygen species (ROS) in human atherothrombosis. Moreover, leukocyte-derived myeloperoxidase (MPO) and red blood cell-derived iron could be involved in the oxidative modification of lipids/lipoproteins (LDL/HDL) in the arterial wall. Interestingly, oxidized lipoproteins, and antioxidants, have been analyzed as potential markers of oxidative stress in the plasma of patients with atherothrombosis. In this review, we will revise sources of ROS, focusing on NADPH oxidase, but also on MPO and iron. We will also discuss the impact of these oxidative systems on LDL and HDL, as well as the value of these modified lipoproteins as circulating markers of oxidative stress in atherothrombosis. We will finish by reviewing some antioxidant systems and compounds as therapeutic strategies to prevent pathological vascular remodeling.

Circulating malondialdehyde-modified low-density lipoprotein (MDA-LDL) as a novel predictor of clinical outcome after endovascular therapy in patients with peripheral artery disease (PAD)

BACKGROUND AND AIMS

Despite advances in the treatment of peripheral artery disease (PAD), cardiovascular events and death rates remain high. This study aimed at identifying markers of outcome in patients with PAD undergoing endovascular therapy (EVT).

METHODS

Consecutive patients undergoing EVT were recruited. Markers of oxidative stress (malondialdehyde-modified low-density lipoprotein [MDA-LDL]), inflammation (IL-6; high-sensitivity C-reactive protein [hsCRP]) and fibrinolysis (D-dimer) were measured pre-EVT and at post-EVT time-points to 36 h. Clinical follow-up assessed major cardiovascular and/or limb events.

RESULTS

In the 35 patients enrolled, mean MDA-LDL levels decreased from a baseline level of 106.2 U/L to 72.6 U/L immediately post-EVT (p<0.0001); levels remained significantly reduced at all time-points. IL-6, hsCRP and D-dimer increased and were significantly higher at the 36 h time-point. A significant, negative association was seen between decreased MDA-LDL and pre-EVT hsCRP levels (r = -0.42, p=0.012). Clinical follow-up data were obtained for a mean period of 16 months. MDA-LDL ratios (obtained by comparison of post- and pre-EVT values) allowed assessment of high (≥0.495) and low (<0.495) ratio groups. A significantly higher rate of major adverse events, including limb-related events or death, was seen in the low ratio group (p<0.001). Cox proportional hazard analysis including traditional risk factors indicated that this ratio is a significant predictor of clinical endpoints (HR = 0.4210, p=0.0154). An association with clinical outcome was not observed with the other candidate biomarkers.

CONCLUSIONS

Assessment of pre- and post-EVT MDA-LDL levels is a promising marker of clinical outcome in patients with PAD.

Streptococcus thermophilus fermented milk reduces serum MDA-LDL and blood pressure in healthy and mildly hypercholesterolaemic adults

Low-density lipoprotein (LDL)-cholesterol, malondialdehyde-modified low-density lipoprotein (MDA-LDL), MDA-LDL/LDL-cholesterol in serum, and blood pressure are considered useful risk markers of cardiovascular diseases. This study aimed to examine whether a fermented milk containing Streptococcus thermophilus YIT 2001 (ST), which has high anti-oxidative activity, would benefit healthy and mildly hyper-LDL-cholesterolaemic adults via a randomised, double-blind, placebo-controlled trial. ST-fermented milk or non-fermented placebo milk (PC) was consumed once a day for 12 weeks by 29 and 30 subjects, respectively, with average serum LDL-cholesterol levels of about 140 mg/dl. Serum levels of LDL-cholesterol and MDA-LDL and blood pressure were analysed before (baseline) and after consumption. Comparisons of the responses between both groups were assessed using analysis of covariance (ANCOVA, with the baseline value as the covariate). ANCOVA demonstrated that the ST group had significant reductions in MDA-LDL, MDA-LDL/LDL-cholesterol, systolic blood pressure (SBP), and diastolic blood pressure (DBP) compared with the PC group during the consumption period (P<0.05). Moreover, stratified analysis revealed that there were significant reductions in MDA-LDL, MDA-LDL/LDL-cholesterol, SBP, and DBP in the ST group compared with the PC group during the consumption period in subjects who had above median (65 U/l) levels of oxidative stress marker MDA-LDL at baseline (P<0.05), but not in subjects with levels below the median. These findings suggest that daily consumption of ST-fermented milk may be beneficial in healthy or mildly hyper-LDL cholesterolaemic subjects through reductions in risk marker values of oxidative stress and/or cardiovascular diseases. The benefits were particularly remarkable in subjects who had higher levels of MDA-LDL.

Impact of Malondialdehyde-Modified Low-Density Lipoprotein on Tissue Characteristics in Patients With Stable Coronary Artery Disease - Integrated Backscatter-Intravascular Ultrasound Study

BACKGROUND

Malondialdehyde-modified low-density lipoprotein (MDA-LDL) is considered to play an essential role in plaque destabilization. We aimed to investigate the association between the tissue characteristics of culprit plaque assessed by integrated backscatter (IB)-intravascular ultrasound (IVUS) and the serum MDA-LDL levels in patients with stable coronary artery disease.

METHODS AND RESULTS

The study group consisted of 179 patients undergoing IB-IVUS during elective percutaneous coronary intervention. Patients were classified into 2 groups based on serum MDA-LDL level: low MDA-LDL group (<102 U/L, n=88) and high MDA-LDL group (≥102 U/L, n=91). Plaques in the high MDA-LDL group had higher %lipid (45.2±12.5% vs. 54.9±14.5%, P<0.001) and lower %fibrosis (43.0±9.1% vs. 36.4±11.4%, P<0.001) than did plaques in the low MDA-LDL group. Lipid-rich plaque (%lipid >60% or %fibrosis <30%) was significantly more frequently found in the high MDA-LDL group than in the low MDA-LDL group (14.3% vs. 39.8%, P<0.001). The incidence of MACE (cardiac death, myocardial infarction and/or hospitalization for heart failure) during 3 years was significantly higher in the high MDA-LDL group than in the low MDA-LDL group (6.6% vs. 15.9%, P=0.02).

CONCLUSIONS

Higher MDA-LDL might be associated with greater lipid and lower fibrous content, contributing to coronary plaque vulnerability. (Circ J 2016; 80: 2173-2182).

Matrix Metalloproteinase-9 as a Marker for Plaque Rupture and a Predictor of Adverse Clinical Outcome in Patients with Acute Coronary Syndrome: An Optical Coherence Tomography Study

OBJECTIVES

The present study sought to clarify the relationship between matrix metalloproteinase-9 (MMP-9) levels and plaque morphology demonstrated by optical coherence tomography (OCT), and to examine their prognostic impacts in patients with acute coronary syndrome (ACS).

METHODS

MMP-9 levels were measured for patients with ACS (n = 249). Among 249 patients, 120 with evaluable OCT images were categorized into patients with ruptured plaques (n = 65) and those with nonruptured plaques (n = 55) on the basis of culprit lesion plaque morphology demonstrated by OCT.

RESULTS

MMP-9 levels on admission were significantly higher in the rupture group than in the nonrupture group (p = 0.029). Although creatine kinase-MB (CK-MB) on admission was comparable between the groups, peak CK-MB was higher in the rupture group than in the nonrupture group (p < 0.001). By receiver operating characteristic curve analysis, the optimal cut-off value of MMP-9 to detect ruptured plaques was 65.5 ng/ml (p = 0.029). There was a nonstatistically significant trend toward increased cardiac death at 2 years (5.9 vs. 1.0%, p = 0.059) in patients with high MMP-9 (≥65.5 ng/ml) compared to those with low MMP-9 (<65.5 ng/ml).

CONCLUSIONS

MMP-9 can differentiate ACS with ruptured plaques from nonruptured plaques, and MMP-9 may be a valuable predictor of long-term cardiac mortality in patients with ACS reflecting plaque rupture.

Type D Personality and Coronary Plaque Vulnerability in Patients With Coronary Artery Disease: An Optical Coherence Tomography Study

OBJECTIVE

To investigate the association between Type D personality and higher incidence of major adverse cardiac events, we used in vivo optical coherence tomography (OCT) to evaluate the association between Type D with coronary plaque characteristics.

METHODS

A total of 109 patients who had culprit coronary plaque (s) were included in the study. The Type D construct was analyzed using both the categorized and the continuous approaches. Plaque vulnerability of culprit lesions was measured by OCT.

RESULTS

After adjusting for demographic and clinical factors, multivariate analysis demonstrated that Type D was associated with lipid plaque (odds ratio [OR] = 4.87, 95% confidence interval [CI] = 1.41-11.14, p = .025), thin cap fibroatheroma (OR = 3.84, 95% CI = 1.36-10.85, p = .011), and fibrous cap thickness (β = -1.43, standard error = 0.04, p = .001) analyzed by categorical approach. When analyzing Type D as continuous variable, the negative affectivity component was significantly related to plaque vulnerability, including lipid plaque (OR = 3.43, 95% CI = 1.23-9.52, p = .018), thin cap fibroatheroma (OR = 2.20, 95% CI = 1.10-4.40, p = .026), and fibrous cap thickness (β = -0.05, standard error = 0.02, p = .030), whereas no associations between the negative affectivity by social inhibition interaction term with OCT indices were found.

CONCLUSIONS

The results suggest that plaque characteristics in Type D have more features of plaque vulnerability. The negative affectivity component seems to drive the associations between Type D and vulnerable plaques. These findings provide new insights into the mechanism involved in the association between Type D and major adverse cardiac event.

Inflammatory Biomarkers and Atherosclerosis

Atherosclerosis has been regarded as a form of chronic vascular inflammation. Numerous biomarkers associated with inflammation have been identified as novel targets to monitor atherosclerosis and cardiovascular risk. C-reactive protein (CRP) is one of the most actively studied and established inflammatory biomarkers for cardiovascular events. However, CRP response is triggered by many disorders unrelated to cardiovascular disease, which interferes with the clinical application. This review describes established and traditional inflammatory biomarkers including CRP as well as novel inflammatory biomarkers reflective of local atherosclerotic inflammation. In addition, we focus on the potential usefulness of inflammatory biomarkers in developing anti-atherosclerotic therapeutic approaches.

Low eicosapentaenoic acid to arachidonic acid ratio is associated with thin-cap fibroatheroma determined by optical coherence tomography

BACKGROUND

A low eicosapentaenoic acid (EPA)/arachidonic acid (AA) ratio is known to be associated with cardiovascular events. However, the relationship between the EPA/AA ratio and coronary plaque vulnerability assessed by optical coherence tomography (OCT) has not been examined thoroughly. This study examined the relationship between the EPA/AA ratio and coronary plaque vulnerability assessed by OCT in patients with acute coronary syndrome (ACS).

METHODS

We evaluated 59 ACS patients who had undergone percutaneous coronary intervention using OCT. We divided them into 2 groups according to OCT findings-those with and without thin-cap fibroatheroma (TCFA)-and compared the EPA/AA ratio between the groups.

RESULTS

We identified 32 and 27 patients with and without TCFA, respectively. The EPA/AA ratio was significantly lower in patients with TCFA than in those without TCFA [0.35, interquartile range (0.21-0.44) vs. 0.54, interquartile range (0.42-0.70); p<0.001]. In multivariate logistic regression analysis, the EPA/AA ratio was an independent predictor of TCFA (odds ratio, 0.09; 95% confidence interval, 0.007-0.99; p=0.049). The EPA/AA ratio and fibrous cap thickness showed a significant positive correlation (Spearman ρ=0.46; p<0.001). Furthermore, receiver operating characteristic curve analysis showed that an EPA/AA ratio<0.46 could predict TCFA (81.3%, sensitivity; 74.1%, specificity).

CONCLUSIONS

A low serum EPA/AA ratio is significantly associated with coronary plaque vulnerability assessed by OCT in ACS patients.

Assessment of coronary atherosclerosis using optical coherence tomography

Optical coherence tomography (OCT) is a catheter-based imaging system that uses near-infrared light to produce cross-sectional images of the coronary arteries. With its extraordinarily high resolution (10-20 μm), OCT allows clinicians to observe various morphological features of coronary atherosclerosis in vivo. For example, intimal thickening presents as homogeneous, signal-rich regions on OCT, while fibroatheroma with a lipid-rich necrotic core is characterized by the presence of signal-poor regions with a diffuse border. Furthermore, plaque rupture is detected in 50〜70% of culprit lesions of acute coronary syndrome (ACS), and plaque erosion develops over areas of intimal thickening and/or thick-cap fibroatheroma. Meanwhile, calcified nodules are common in older patients with hypertension and chronic renal disease. Platelet-rich thrombi are visualized as low backscattering structures and often detected in patients with unstable angina, whereas red blood cell-rich thrombi exhibit a high backscattering structure with signal-free shadowing and are frequently noted in patients with acute myocardial infarction. Moreover, OCT-derived thin cap fibroatheroma has been shown to be a predictor of subsequent plaque progression and acute coronary events, while vasa vasorum and the macrophage density are associated with a thin fibrous cap and large necrotic core as well as increased serum levels of inflammatory biomarkers. One current challenge of OCT examinations is to detect morphologic characteristics capable of discriminating vulnerable from stable plaques. The ability to detect vulnerable plaques in vivo would allow physicians to identify patients at high risk for adverse coronary events, thus significantly helping to prevent ACS.

EuroEcho-Imaging 2013: highlights

The annual meeting of the European Association of Echocardiography (EuroEcho-Imaging) was held in Istanbul, Turkey. In the present paper, we present a summary of the 'Highlights' session.

Inflammatory biomarkers for predicting cardiovascular disease

The pathology of cardiovascular disease (CVD) is complex; multiple biological pathways have been implicated, including, but not limited to, inflammation and oxidative stress. Biomarkers of inflammation and oxidative stress may serve to help identify patients at risk for CVD, to monitor the efficacy of treatments, and to develop new pharmacological tools. However, due to the complexities of CVD pathogenesis there is no single biomarker available to estimate absolute risk of future cardiovascular events. Furthermore, not all biomarkers are equal; the functions of many biomarkers overlap, some offer better prognostic information than others, and some are better suited to identify/predict the pathogenesis of particular cardiovascular events. The identification of the most appropriate set of biomarkers can provide a detailed picture of the specific nature of the cardiovascular event. The following review provides an overview of existing and emerging inflammatory biomarkers, pro-inflammatory cytokines, anti-inflammatory cytokines, chemokines, oxidative stress biomarkers, and antioxidant biomarkers. The functions of each biomarker are discussed, and prognostic data are provided where available.