Interleukin-6 as a predictor of cardiovascular events in troponin-negative non-ST elevation acute coronary syndrome patients

Immune-related biomarkers in myocardial infarction; diagnostic/prognostic value and therapeutic potential

The incidence of myocardial infarction (MI) is increasing worldwide on an annual basis. The incorporation of circulating biomarkers, along with electrocardiography, echocardiography, coronary angiograms, and other diagnostic techniques, is essential in the evaluation, prediction, and therapeutic efficacy assessment of patients afflicted with MI. Biomarker evaluation has been employed in the diagnosis of MI for over five decades. Further biomarker research can be carried out as newer biomarkers have been discovered in pathways such as inflammatory response, neurohormonal stimulation, or myocardial stress that initiate significantly earlier than myocyte necrosis and the diagnostic establishment of cardiac troponins. The assessment of biomarkers for MI is on the brink of a significant transformation due to advancements in comprehending the intricate pathophysiology of the condition. This has led to a pursuit of innovative biomarkers that could potentially overcome the limitations of current biomarkers. For individuals with a high-risk profile, this may facilitate tailoring of appropriate treatment. This review places emphasis on a diverse array of biomarkers that have the potential to offer diagnostic and prognostic information, as well as the latest clinical and preclinical evidence that is driving theoretical advancements in cardiovascular immunotherapy.

IL-6, IL-1β and MDA correlate with Thrombolysis in Myocardial Infarction (TIMI) risk score in patients with Acute Coronary Syndrome

BACKGROUND

Inflammation plays a significant role in the pathophysiology of Acute Coronary Syndrome (ACS) but is not included in current risk stratification.

OBJECTIVE

To determine the association between Thrombolysis in Myocardial Infarction (TIMI) risk score and inflammatory biomarkers in the ACS, including unstable angina (UA), non-ST segment elevation myocardial infarction (NSTEMI), and ST-segment elevation myocardial infarction (STEMI). We hypothesized that including inflammatory biomarkers could add prognostic value to the TIMI risk score.

METHODS

In this cross-sectional study, serum levels of interleukins (IL)-6 and IL-1β and MDA (malondialdehyde) were quantified by ELISA and colorimetry, respectively , patients with ACS (n = 48; 31.3% with UA, 33.3% with NSTEMI, and 35.4% with STEMI) and healthy controls (n = 43). We assessed the TIMI scores in the first 24 h after symptom onset.

RESULTS

The results showed that patients with ACS had significantly higher levels (p<0.05) of the inflammatory biomarkers IL-6, IL-1β, and MDA compared to the control group. However, we found no significant differences in IL-6, IL-1β, and MDA levels among the patients with ACS according to their classification as UA, NSTEMI, and STEMI. Positive correlations were observed between TIMI and IL-6 (r=0.68), IL-1β (r= 0.53), and MDA (r=0.58) in patients with UA and between TIMI and IL-1β (r= 0.62) in STEMI patients.

CONCLUSION

These data suggest the presence of a pro-inflammatory profile in patients with ACS as well as positive correlations between TIMI scores and the inflammatory biomarkers IL-6, IL-1β, and MDA in patients with UA and between TIMI scores and IL-1β in patients with STEMI. Combining inflammatory biomarkers with the TIMI risk score could provide better insight into the processes involved in ACS.

Meta-analysis of the relationship between interleukin-6 levels and the prognosis and severity of acute coronary syndrome

This study aimed to explore the relationship between plasma interleukin 6 (IL-6) levels, adverse cardiovascular events, and the severity of acute coronary syndrome (ACS). A literature review was performed of studies regarding IL-6 and ACS extracted from databases including EMBASE, Cqvip, MEDLINE, Web of Knowledge, PubMed, Cochrane Library, China National Knowledge Infrastructure, and Wanfang data. The Newcastle-Ottawa scale (NOS) was used to evaluate the quality of the literature. The literature was screened, its quality was evaluated, and relevant data were extracted for performing meta-analysis using RevMan software (version 5.3). A total of 524 studies were included in the initial survey. After several rounds of screening and analysis, six studies met the inclusion criteria and underwent meta-analysis using a fixed-effect model. Patients were divided into non-severe and severe groups based on the concentration of high-sensitivity C-reactive protein. Meta-analysis of the relationship between IL-6 and the severity of ACS showed that the plasma IL-6 level of patients in the severe group was significantly higher than that of patients in the non-severe group (p<0.00001). Additionally, patients with experience of major adverse cardiovascular events had significantly higher plasma IL-6 levels than did patients without experience of such events (p<0.00001). In summary, patients with ACS and high IL-6 levels tended to be in a critical condition, with a higher risk of adverse cardiovascular events and worse prognosis. Thus, IL-6 levels could indicate whether patients with ACS may have adverse cardiovascular events and determine the severity of ACS.

Biomarkers of acute myocardial infarction: diagnostic and prognostic value. Part 2 (Literature review)

In the second part of the review, we continue the discussion of biomarkers that have a diagnostic and prognostic significance in acute myocardial infarction (AMI). The study of the AMI pathophysiology through the experimental and clinical research contributes to the discovery of new regulatory molecules and pathogenetic mechanisms underlying AMI. At the same time, many molecules involved in the pathogenesis of AMI can be used as effective biomarkers for the diagnosis and prediction of AMI. This article discusses in detail the diagnostic and prognostic value of inflammatory biomarkers of AMI (C-reactive protein, interleukin-6, tumor necrosis factor-alpha, myeloperoxidase, matrix metalloproteinases, soluble form of CD40 ligand, procalcitonin, placental growth factor) and a number of recently discovered new biomarkers of AMI (microribonucleic acids, galectin-3, stimulating growth factor expressed by gene 2, growth differentiation factor 15, proprotein convertase of subtilisin-kexin type 9).

Post-Myocardial Infarction Ventricular Remodeling Biomarkers-The Key Link between Pathophysiology and Clinic

Studies in recent years have shown increased interest in developing new methods of evaluation, but also in limiting post infarction ventricular remodeling, hoping to improve ventricular function and the further evolution of the patient. This is the point where biomarkers have proven effective in early detection of remodeling phenomena. There are six main processes that promote the remodeling and each of them has specific biomarkers that can be used in predicting the evolution (myocardial necrosis, neurohormonal activation, inflammatory reaction, hypertrophy and fibrosis, apoptosis, mixed processes). Some of the biomarkers such as creatine kinase-myocardial band (CK-MB), troponin, and N-terminal-pro type B natriuretic peptide (NT-proBNP) were so convincing that they immediately found their place in the post infarction patient evaluation protocol. Others that are related to more complex processes such as inflammatory biomarkers, atheroma plaque destabilization biomarkers, and microRNA are still being studied, but the results so far are promising. This article aims to review the markers used so far, but also the existing data on new markers that could be considered, taking into consideration the most important studies that have been conducted so far.

Predictive Value of Blood Interleukin-6 Level in Patients with Acute Coronary Syndrome: A Meta-analysis

OBJECTIVE

Conflicting results have been reported on the association between blood level of interleukin-6 and adverse outcomes in patients with acute coronary syndrome (ACS). The current meta-analysis aimed to evaluate the predictive utility of elevated blood interleukin-6 level in patients with ACS.

METHODS

A systematically literature search was performed using PubMed and Embase databases up to December 31, 2019. Observational studies or post hoc analysis of randomized controlled trials investigating the values of blood interleukin-6 level for predicting major adverse cardiovascular events (MACE including death, re-infarction, revascularization, angina, heart failure, malignant arrhythmia, or stroke), all-cause mortality or cardiovascular mortality in ACS patients were eligible. The predictive values were summarized by pooling the multivariable-adjusted risk ratio (RR) and 95% confidence intervals (CI) for the highest versus lowest category of interleukin-6 level.

RESULTS

Thirteen studies enrolling 30,289 patients with ACS were included. When comparing the highest with lowest category of interleukin-6 level, the pooled RR was 1.29 (95% CI 1.12-1.48) for MACE, 1.50 (95% CI 1.35-1.67) for all-cause mortality, and 1.55 (95% CI 1.06-2.28) for cardiovascular mortality, respectively. Moreover, the predictive values of interleukin-6 level on MACE were consistently found in different study designs, subtypes of patients, sample sizes, follow-up duration, and cutoff value of interleukin-6 elevation subgroups.

CONCLUSION

Increased blood level of interleukin-6may be independently associated with higher risk of MACE, cardiovascular and all-cause mortality in patients with ACS. Measurement of blood interleukin-6 level has potential to improve risk stratification of ACS.

Pro-inflammatory Cytokines in Acute Coronary Syndromes

BACKGROUND

Over the last decades, the role of inflammation and immune system activation in the initiation and progression of coronary artery disease (CAD) has been established.

OBJECTIVES

The study aimed to present the interplay between cytokines and their actions preceding and shortly after ACS.

METHODS

We searched in a systemic manner the most relevant articles to the topic of inflammation, cytokines, vulnerable plaque and myocardial infarction in MEDLINE, COCHRANE and EMBASE databases.

RESULTS

Different classes of cytokines (intereleukin [IL]-1 family, Tumor necrosis factor-alpha (TNF-α) family, chemokines, adipokines, interferons) are implicated in the entire process leading to destabilization of the atherosclerotic plaque, and consequently, to the incidence of myocardial infarction. Especially IL-1 and TNF-α family are involved in inflammatory cell accumulation, vulnerable plaque formation, platelet aggregation, cardiomyocyte apoptosis and adverse remodeling following the myocardial infarction. Several cytokines such as IL-6, adiponectin, interferon-γ, appear with significant prognostic value in ACS patients. Thus, research interest focuses on the modulation of inflammation in ACS to improve clinical outcomes.

CONCLUSION

Understanding the unique characteristics that accompany each cytokine-cytokine receptor interaction could illuminate the signaling pathways involved in plaque destabilization and indicate future treatment strategies to improve cardiovascular prognosis in ACS patients.

Associations of ACE I/D polymorphism with the levels of ACE, kallikrein, angiotensin II and interleukin-6 in STEMI patients

This study aimed to compare the plasma levels of angiotensin-I converting enzyme (ACE), Angiotensin II (AngII), kallikrein (KLK1) and interleukin-6 (IL-6) in ST segment elevation myocardial infarction (STEMI) patients with different ACE Insertion/deletion (I/D) polymorphisms in a Chinese population. The ACE genotypes were determined in the 199 STEMI patients and 216 control subjects. STEMI patients were divided into three groups based on the ACE genotypes. Single polymerase chain reaction (PCR) was performed to characterize ACE I/D polymorphisms. Plasma levels of ACE, AngII, KLK1 and IL-6 were measured by enzyme-linked immunosorbent assay (ELISA). We found that the DD or ID genotype was significantly independently associated with high ACE (OR = 4.697; 95% CI = 1.927–11.339), KLK1 (3.339; 1.383–8.063) and IL-6 levels (OR = 2.10; 1.025–4.327) in STEMI patients. However, there was no statistical significance between the ACE I/D polymorphism and AngII plasma levels whether in univariate or multivariate logistic regression. Additionally, we detected a significantly positive correlation between plasma KLK1 levels and IL-6 levels in STEMI patients (r = 0.584, P < 0.001). The study showed high levels of ACE, KLK1 and IL-6 were detected when the D allele was present, but AngII plasma levels was not influenced by the ACE I/D polymorphism.

Diagnostic and prognostic value of biomarkers in acute myocardial infarction

The incidence of acute myocardial infarction (AMI) has been increasing rapidly in recent years, seriously endangering human health. Cardiac biomarkers play critical roles in the diagnosis and prognosis of AMI. Troponin is a highly sensitive and specific biomarker for AMI diagnosis and can independently predict adverse cardiac events. Other biomarkers such as N-terminal B-type natriuretic peptide and C reactive protein are also valuable predictors of cardiovascular prognosis. Recently, several novel biomarkers have been identified for the diagnosis and risk assessment in patients with AMI. A multibiomarker approach can potentially enhance the diagnostic accuracy and provide more information for the early risk stratification of AMI. In this review, we will summarise the biomarkers discovered in recent years and focus on their diagnostic and prognostic value for patients with AMI.

The Therapeutic Efficacy of Danhong Injection Combined With Percutaneous Coronary Intervention in Acute Coronary Syndrome: A Systematic Review and Meta-Analysis

Background: Percutaneous coronary intervention (PCI) is widely used in treatment of acute coronary syndrome (ACS) clinically. It is believed that Danhong injection (DHI) extracted from salviae miltiorrhizae and flos carthami combined with PCI could increase the therapeutic efficacy on ACS. We provide an updated meta-analysis with detailed information on combination of DHI and PCI therapy.

Materials and Methods: Electronic databases were searched for appropriate articles without language limitations on key words before October 22, 2017. All trails were screened according to certain criteria. Quality of eligible studies was also assessed. We made a detailed record of outcome measurements. RevMan 5.3 software was used to perform the meta-analysis.

Results: 14 articles involving 1533 patients with ACS were selected. Compared to PCI treatment alone, total efficacy rate (TER) was enhanced and major adverse cardiovascular events (MACE) were reduced significantly for the combination of DHI and PCI (P < 0.00001). Vascular endothelial function was improved by significantly decreasing the contents of ET-1, vWF and increasing the levels of NO and FMD (P < 0.00001). The serum levels of IL-1, IL-6, IL-18, TNF-α, LpPLA2, MMP-9, and pentraxin-3 were significantly decreased (P < 0.00001), whereas IL-10 in serum was increased (P < 0.00001), indicating a stronger anti-inflammatory effect of the combination. The combination therapy decreased the serum levels of CD62P, PAGT, PADT, FIB-C significantly (P < 0.05), which was beneficial for preventing coagulation of platelets. Blood lipid was also affected by regulating TC, TG, LDL, and HDL, but the results were not statistically significant (P > 0.05). Cardiac function was improved by increasing LEVF (P = 0.006) but not LVED (P = 0.08). The combination treatment was associated with an improvement in antioxidant effect by decreasing MDA and increasing SOD significantly (P < 0.00001).

Conclusion: Combination of DHI and PCI in treatment of ACS could improve TER and reduce incidence of MACE after PCI therapy. These effects may be mediated by combined actions of several mechanisms. However, these results of this study should be handled cautiously due to the limitations of this research. Several rigorous RCTs are in need to confirm these findings.

Age-related limitations of interleukin-6 in predicting early mortality in acute ST-elevation myocardial infarction

Interleukin-6 (IL-6) is an inflammatory cytokine whose levels increase significantly during myocardial infarction (MI).

It has been hypothesised that the concentrations of IL-6 at admission may be useful in prognosticating long-term outcomes. It is unclear, however, whether IL-6 could improve the prognosis of early mortality in MI.

We have compared serum IL-6 levels and analysed the disease course in 158 patients with ST-elevation MI (STEMI) who either survived (n = 148) or died (n = 10) within 30 days following the admission. Patients were treated in a single university centre with primary percutaneous coronary intervention (PCI).

The non-survivors (6.3%) displayed most of typical risk factors for poor outcome. In addition they had significantly higher concentrations of IL-6 at hospital admission (median values 8.5 vs. 2.0 pg/ml; p = 0.038). However, they were also significantly older than the survivors (median values 72 vs. 57 years; p = 0.0001). IL-6 levels are known to increase with age and we could confirm a significant correlation between patients’ calendar age and circulating IL-6 (p = 0.009). Regression analysis revealed that IL-6 concentrations were significantly affected by patients’ age but they did not independently relate to patients’ outcome.

Such results indicate that circulating IL-6 at admission may be of limited value in predicting early mortality in STEMI. It is important to recognize that, because of the small group of patients who died (N = 10), the results must be interpreted with caution. Therefore, we stress that these results should be viewed as preliminary and further validated in a larger set of patients.