Interleukin 18 and coronary heart disease: prospective study and systematic review

Association of carotid atheroma plaque with IL-18 levels and with polymorphisms in the IL-18 receptor gene in a Mediterranean population

BACKGROUND

Atherosclerosis is an inflammatory disease. Interleukin 18 (IL-18) is an inflammatory molecule that has been linked to the development of atherosclerosis and cardiovascular disease.

OBJECTIVE

To evaluate the possible relationship between plasma levels of IL-18 and the presence of atherosclerosis evaluated at the carotid level, as well as to analyze the possible modulation by different polymorphisms in a Mediterranean population.

MATERIAL AND METHODS

Seven hundred and forty-six individuals from the metropolitan area of Valencia were included, recruited over a period of 2 years. Hydrocarbon and lipid metabolism parameters were determined using standard methodology and IL-18 using ELISA. In addition, carotid ultrasound was performed and the genotype of four SNPs related to the IL-18 signaling pathway was analyzed.

RESULTS

Patients with higher plasma levels of IL-18 had other associated cardiovascular risk factors. Elevated IL-18 levels were significantly associated with higher carotid IMT and the presence of atheromatous plaques. The genotype with the A allele of the SNP rs2287037 was associated with a higher prevalence of carotid atheromatous plaque. On the contrary, the genotype with the C allele of the SNP rs2293224 was associated with a lower prevalence of atheromatous plaque.

CONCLUSIONS

High levels of IL-18 were significantly associated with a higher carotid IMT and the presence of atheromatous plaques, which appear to be influenced by genetic factors, as evidenced by associations between SNPs in the IL-18 receptor gene and the presence of atheroma plaque.

Galectin-3, Galectin-9, and Interleukin-18 Are Associated with Monocyte/Macrophage Activation and Turnover More so than Simian Immunodeficiency Virus-Associated Cardiac Pathology or Encephalitis

Despite antiretroviral therapy (ART), people living with HIV (PLWH) are at increased risk of developing cardiovascular disease (CVD) and HIV-associated neurocognitive disorder (HAND), among other comorbidities. Studies from ART-treated individuals identified galectin-3 (gal-3) and interleukin (IL)-18 as CVD biomarkers, galectin-9 (gal-9) as a HAND biomarker, and sCD163, a marker of monocyte/macrophage activation, as a biomarker of both. We asked if plasma gal-3, gal-9, and IL-18 are associated with an individual comorbidity or increase in both with animals that develop AIDS with both pathologies versus (CVD-path) alone or simian immunodeficiency virus encephalitis (SIVE) alone. We found that no biomarkers were selective between individual pathologies, and all biomarkers increased with co-development of CVD-path and SIVE (gal-3, p = 0.11; gal-9, p = 0.001; IL-18, p = 0.007; sCD163, p < 0.001; %BrdU p = 0.02). Although gal-3, gal-9, and IL-18 did not distinguish between pathologies, they correlated strongly with one another, with sCD163, a marker of monocyte/macrophage activation, and the %BrdU monocytes, a marker of monocyte turnover. Compared to animals with CVD-path or SIVE alone, animals that co-developed both pathologies had consistently elevated IL-18 throughout infection (p = 0.02) and increased sCD163 in late infection (p = 0.01). These data indicate that gal-3, gal-9, and IL-18 are associated with monocyte/macrophage activation by sCD163 and monocyte turnover by the %BrdU+ monocytes more so than CVD-path or SIVE.

Macrophages in cardiovascular diseases: molecular mechanisms and therapeutic targets

The immune response holds a pivotal role in cardiovascular disease development. As multifunctional cells of the innate immune system, macrophages play an essential role in initial inflammatory response that occurs following cardiovascular injury, thereby inducing subsequent damage while also facilitating recovery. Meanwhile, the diverse phenotypes and phenotypic alterations of macrophages strongly associate with distinct types and severity of cardiovascular diseases, including coronary heart disease, valvular disease, myocarditis, cardiomyopathy, heart failure, atherosclerosis and aneurysm, which underscores the importance of investigating macrophage regulatory mechanisms within the context of specific diseases. Besides, recent strides in single-cell sequencing technologies have revealed macrophage heterogeneity, cell-cell interactions, and downstream mechanisms of therapeutic targets at a higher resolution, which brings new perspectives into macrophage-mediated mechanisms and potential therapeutic targets in cardiovascular diseases. Remarkably, myocardial fibrosis, a prevalent characteristic in most cardiac diseases, remains a formidable clinical challenge, necessitating a profound investigation into the impact of macrophages on myocardial fibrosis within the context of cardiac diseases. In this review, we systematically summarize the diverse phenotypic and functional plasticity of macrophages in regulatory mechanisms of cardiovascular diseases and unprecedented insights introduced by single-cell sequencing technologies, with a focus on different causes and characteristics of diseases, especially the relationship between inflammation and fibrosis in cardiac diseases (myocardial infarction, pressure overload, myocarditis, dilated cardiomyopathy, diabetic cardiomyopathy and cardiac aging) and the relationship between inflammation and vascular injury in vascular diseases (atherosclerosis and aneurysm). Finally, we also highlight the preclinical/clinical macrophage targeting strategies and translational implications.

Association of IL-18 gene polymorphisms with clinical aspects of hyperlipidemia in middle-aged and early people in the community

Hyperlipidemia is notorious for causing coronary artery disease (CAD). IL-18 is a proinflammtory cytokine that contributes to the pathogenesis of CAD. Previous reports have revealed that genetic polymorphism of IL-18 is associated with its expression level as well as the susceptibility to CAD. In the present study, we aim to investigate the relationship between IL-18 single nucleotide polymorphisms (SNPs) and hyperlipidemia in the Han Chinese population in Taiwan. A total of 580 participants older than 30 were recruited from the community. We collected the demographics, self-reported disease histories, and lifestyles. We also assessed the levels of lipid profiles including total cholesterol (CHOL), triglyceride, low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol. Two SNPs, rs3882891C/A (intron 5) and rs1946518A/C (promoter -607) of IL-18 were elucidated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. Our results revealed that rs3882891 AA was associated with lower risk of hypercholesterolemia, higher CHOL and LDL-C in subjects (p=0.003, p=0.000 and p=0.005 separately), and rs1946518 CC was associated with hypercholesterolemia, higher CHOL and LDL-C as well (p=0.021, p=0.003 and p=0.001 separately) Furthermore, both SNPs were associated with IL-18 expression level, which was examined by Genotype-Tissue Expression (GTEx) Portal (p=0.042 and 0.016 separately). Finally, the haplotype of IL-18 was subsequently arranged in the order of rs3882891 and rs1946518. The result revealed that the AC haplotype of 2 IL-18 SNPs was also associated with lower risk of hypercholesterolemia, lower levels of CHOL and LDL-C (p=0.01, p=0.001 and 0.003). The current study is the first to report the association between IL-18 SNPs and hyperlipidemia in the Chinese Han population.

Accuracy of salivary biomarkers in the diagnosis of periodontal status and coronary heart disease

Inflammatory illnesses, such as periodontitis and atherosclerotic coronary heart disease (ASCHD), trigger the production of pro-inflammatory mediators. The aim of this study was to assess the accuracy of using salivary interleukin-1β (IL-1β), interleukin-18 (IL-18), and gasdermin D (GSDMD) in discerning patients with periodontitis with and without ASCHD from healthy individuals, and to assess their correlation with clinical periodontal parameters and low-density lipoprotein (LDL) levels. The study involved 120 participants: 30 were healthy subjects (control group, C), 30 had generalized periodontitis (group P), 30 had ASCHD and clinically healthy periodontium (group AS-C), and 30 had ASCHD and generalized periodontitis (group AS-P). Saliva and blood samples were collected, and periodontal characteristics such as plaque index, bleeding on probing, probing pocket depth, and clinical attachment loss were examined. IL-1β, IL-18, and GSDMD levels from saliva were determined using ELISA. LDL levels were determined from the blood samples. Groups P, AS-C, and AS-P had higher levels of salivary IL-1β, IL-18, and GSDMD than group C. The receiver operating characteristic (ROC) curves of all biomarkers showed high diagnostic accuracy, with a significant positive correlation with the clinical parameters and LDL levels. The observed correlations between the studied pro-inflammatory mediators and disease severity suggest that these biomarkers could serve as indicators of disease progression in conditions such as periodontitis and ASCHD.

Association Between AIM2 and Pycard Genes Polymorphisms and Susceptibility to Periodontitis with Coronary Heart Disease

Background

Numerous genetic variations in inflammasome components are linked to prevalent disorders in the general population, including periodontitis and cardiovascular illness. Polymorphisms in the genes play a critical in the initiation and development of inflammatory diseases. The limited study on AIM2 gene variation associated with inflammatory disease and no study of PYCARD gene variation associated with inflammatory disease.

Objective

This case-control study was to examine the association between the single nucleotide polymorphism of AIM2 and Pycard genes with susceptibility to periodontitis with and without coronary heart disease, to determine interleuken-18 and gasdermin D levels in the saliva of periodontitis with and without coronary heart disease patients, as well as their correlation with salivary interleuken-18 and gasdermin D levels and clinical periodontal parameters.

Methods

The present study recruited 120 participants: 30 were healthy subjects (control, C), 30 had generalized periodontitis (P), 30 had atherosclerosis coronary heart disease with clinically healthy periodontium (AS-C), and 30 had atherosclerosis coronary heart disease with generalized periodontitis (AS-P). All individuals' demographic data recorded, saliva and blood samples collected, then periodontal characteristics were detailed. These parameters include plaque index, bleeding on probing, probing pocket depth, and clinical attachment loss. AIM2 and Pycard gene polymorphisms were analyzed by polymerase chain reaction assay, electrophoresis and sequencing. An enzyme-linked immunosorbent assay (ELISA) was conducted to determine the level of interleuken-18 and gasdermin D in their saliva.

Results

The study result of high frequency (T) in single-nucleotide polymorphisms. The high genotypes distribution of GT and TT genotypes in the AIM2 gene and the CT and TT genotypes in the Pycard gene were detected in the periodontitis, atherosclerosis coronary heart disease with healthy periodontium and atherosclerosis coronary heart disease with generalized periodontitis groups as compared to control group. Elevation of salivary interleuken-18 and gasdermin D levels in three patients' groups compared to healthy controls. Both these single-nucleotide polymorphisms also significantly correlated with higher salivary interleuken-18 and gasdermin D levels and worse clinical indices of periodontitis.

Conclusion

Single-nucleotide polymorphisms in the AIM2 and Pycard genes are associated with an increased risk of developing periodontitis with and/or without coronary heart disease. Elevation of salivary interleuken-18 and gasdermin D levels associated and impacted on periodontitis with and/or without coronary heart disease. These single-nucleotide polymorphisms may provide evidence for a genetic role in the pathogenesis of periodontitis with and without atherosclerosis coronary heart disease.

Association of interleukin-6 and interleukin-18 with cardiovascular disease in older adults: Atherosclerosis Risk in Communities study

AIMS

Interleukin-6 (IL-6) and interleukin-18 (IL-18), important cytokines implicated in atherosclerosis and inflammaging, were assessed for associations with global cardiovascular disease (CVD), atrial fibrillation (AF), and death in older adults.

METHODS AND RESULTS

Participants from Atherosclerosis Risk in Communities study Visit 5 (mean age 75.4 ± 5.1 years) with IL-6 and IL-18 measurements were included (n = 5672). Cox regression models were used to assess associations of IL-6 and IL-18 with coronary heart disease (CHD), ischaemic stroke, heart failure (HF) hospitalization, global CVD (composite of CHD, stroke, and HF), AF, and all-cause death. Over a median follow-up of 7.2 years, there were 1235 global CVD events, 530 AF events, and 1173 deaths. Higher IL-6 [hazard ratio (HR) 1.57, 95% confidence interval (CI) 1.44-1.72 per log unit increase] and IL-18 (HR 1.13, 95% CI 1.01-1.26) were significantly associated with global CVD after adjustment for cardiovascular risk factors. Association between IL-6 and global CVD remained significant after further adjustment for high-sensitivity C-reactive protein (hs-CRP), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and high-sensitivity troponin T (hs-TnT) but was no longer significant for IL-18 after further adjustments. Interleukin-6 was also associated with increased risk for CHD, HF, and AF after adjustment for covariates. Both IL-6 and IL-18 were associated with increased risk for all-cause death independent of cardiovascular risk factors and other biomarkers.

CONCLUSION

Among older adults, both IL-6 and IL-18 were associated with global CVD and death. The association between IL-6 with CVD appears to be more robust and was independent of hs-CRP, NT-proBNP, and hs-TnT.

Genetic Markers of Insulin Resistance and Atherosclerosis in Type 2 Diabetes Mellitus Patients with Coronary Artery Disease

Type 2 diabetes mellitus (T2DM) is characterized by impaired insulin secretion on a background of insulin resistance (IR). IR and T2DM are associated with atherosclerotic coronary artery disease (CAD). The mechanisms of IR and atherosclerosis are known to share similar genetic and environmental roots. Endothelial dysfunction (ED) detected at the earliest stages of IR might be the origin of atherosclerosis progression. ED influences the secretion of pro-inflammatory cytokines and their encoding genes. The genes and their single nucleotide polymorphisms (SNPs) act as potential genetic markers of IR and atherosclerosis. This review focuses on the link between IR, T2DM, atherosclerosis, CAD, and the potential genetic markers CHI3L1, CD36, LEPR, RETN, IL-18, RBP-4, and RARRES2 genes.

Tissue and Serum Biomarkers in Degenerative Aortic Stenosis-Insights into Pathogenesis, Prevention and Therapy

Background and Aim. Degenerative Aortic Stenosis (DAS) is a common disease that causes substantial morbidity and mortality worldwide, especially in the older population. Our aim was to further investigate novel serum and tissue biomarkers to elucidate biological processes involved in this entity. Material and Methods. We evaluated the expression of six biomarkers significantly involved in cardiovascular pathology, i.e., irisin, periostin, osteoglycin, interleukin 18, high mobility group box 1 and proprotein convertase subtilisin/kexin type 9 in the serum at the protein level, and in the tissue at both the protein and mRNA levels of patients with AS (N = 60). Five normal valves obtained after transplantation from hearts of patients with idiopathic dilated cardiomyopathy were also studied. Serum measurements were also performed in 22 individuals without valvular disease who served as controls (C). Results. Higher levels of all factors were found in DAS patients’ serum than in normal C. IHC and PCR mRNA tissue analysis showed the presence of all biomarkers in the aortic valve cusps with DAS, but no trace of PCR mRNA was found in the five transplantation valves. Moreover, periostin serum levels correlated significantly with IHC and mRNA tissue levels in AS patients. Conclusion. We showed that six widely prevalent biomarkers affecting the atherosclerotic process were also involved in DAS, suggesting a strong osteogenic and pro-inflammatory profile, indicating that aortic valve calcification is a multifactorial biological process.

Vascular Function, Systemic Inflammation, and Coagulation Activation 18 Months after COVID-19 Infection: An Observational Cohort Study

INTRODUCTION

Among its effect on virtually all other organs, COVID-19 affects the cardiovascular system, potentially jeopardizing the cardiovascular health of millions. Previous research has shown no indication of macrovascular dysfunction as reflected by carotid artery reactivity, but has shown sustained microvascular dysfunction, systemic inflammation, and coagulation activation at 3 months after acute COVID-19. The long-term effects of COVID-19 on vascular function remain unknown.

MATERIALS AND METHODS

This cohort study involved 167 patients who participated in the COVAS trial. At 3 months and 18 months after acute COVID-19, macrovascular dysfunction was evaluated by measuring the carotid artery diameter in response to cold pressor testing. Additionally, plasma endothelin-1, von Willebrand factor, Interleukin(IL)-1ra, IL-6, IL-18, and coagulation factor complexes were measured using ELISA techniques.

RESULTS

The prevalence of macrovascular dysfunction did not differ between 3 months (14.5%) and 18 months (11.7%) after COVID-19 infection (p = 0.585). However, there was a significant decrease in absolute carotid artery diameter change, 3.5% ± 4.7 vs. 2.7% ± 2.5, p-0.001, respectively. Additionally, levels of vWF:Ag were persistently high in 80% of COVID-19 survivors, reflecting endothelial cell damage and possibly attenuated endothelial function. Furthermore, while levels of the inflammatory cytokines interleukin(IL)-1RA and IL-18 were normalized and evidence of contact pathway activation was no longer present, the concentrations of IL-6 and thrombin:antithrombin complexes were further increased at 18 months versus 3 months (2.5 pg/mL ± 2.6 vs. 4.0 pg/mL ± 4.6, p = 0.006 and 4.9 μg/L ± 4.4 vs. 18.2 μg/L ± 11.4, p < 0.001, respectively).

DISCUSSION

This study shows that 18 months after COVID-19 infection, the incidence of macrovascular dysfunction as defined by a constrictive response during carotid artery reactivity testing is not increased. Nonetheless, plasma biomarkers indicate sustained endothelial cell activation (vWF), systemic inflammation (IL-6), and extrinsic/common pathway coagulation activation (FVII:AT, TAT) 18 months after COVID-19 infection.

Initial and ongoing tobacco smoking elicits vascular damage and distinct inflammatory response linked to neurodegeneration

Tobacco smoking is strongly linked to vascular damage contributing to the development of hypertension, atherosclerosis, as well as increasing the risk for neurodegeneration. Still, the involvement of the innate immune system in the development of vascular damage upon chronic tobacco use before the onset of clinical symptoms is not fully characterized. Our data provide evidence that a single acute exposure to tobacco elicits the secretion of extracellular vesicles expressing CD105 and CD49e from endothelial cells, granting further recognition of early preclinical biomarkers of vascular damage. Furthermore, we investigated the effects of smoking on the immune system of healthy asymptomatic chronic smokers compared to never-smokers, focusing on the innate immune system. Our data reveal a distinct immune landscape representative for early stages of vascular damage in clinically asymptomatic chronic smokers, before tobacco smoking related diseases develop. These results indicate a dysregulated immuno-vascular axis in chronic tobacco smokers that are otherwise considered as healthy individuals. The distinct alterations are characterized by increased CD36 expression by the blood monocyte subsets, neutrophilia and increased plasma IL-18 and reduced levels of IL-33, IL-10 and IL-8. Additionally, reduced levels of circulating BDNF and elevated sTREM2, which are associated with neurodegeneration, suggest a considerable impact of tobacco smoking on CNS function in clinically healthy individuals. These findings provide profound insight into the initial and ongoing effects of tobacco smoking and the potential vascular damage contributing to neurodegenerative disorders, specifically cerebrovascular dysfunction and dementia.

SGLT2 inhibitor ameliorates endothelial dysfunction associated with the common ALDH2 alcohol flushing variant

The common aldehyde dehydrogenase 2 (ALDH2) alcohol flushing variant known as ALDH2*2 affects ∼8% of the world's population. Even in heterozygous carriers, this missense variant leads to a severe loss of ALDH2 enzymatic activity and has been linked to an increased risk of coronary artery disease (CAD). Endothelial cell (EC) dysfunction plays a determining role in all stages of CAD pathogenesis, including early-onset CAD. However, the contribution of ALDH2*2 to EC dysfunction and its relation to CAD are not fully understood. In a large genome-wide association study (GWAS) from Biobank Japan, ALDH2*2 was found to be one of the strongest single-nucleotide polymorphisms associated with CAD. Clinical assessment of endothelial function showed that human participants carrying ALDH2*2 exhibited impaired vasodilation after light alcohol drinking. Using human induced pluripotent stem cell-derived ECs (iPSC-ECs) and CRISPR-Cas9-corrected ALDH2*2 iPSC-ECs, we modeled ALDH2*2-induced EC dysfunction in vitro, demonstrating an increase in oxidative stress and inflammatory markers and a decrease in nitric oxide (NO) production and tube formation capacity, which was further exacerbated by ethanol exposure. We subsequently found that sodium-glucose cotransporter 2 inhibitors (SGLT2i) such as empagliflozin mitigated ALDH2*2-associated EC dysfunction. Studies in ALDH2*2 knock-in mice further demonstrated that empagliflozin attenuated ALDH2*2-mediated vascular dysfunction in vivo. Mechanistically, empagliflozin inhibited Na⁺/H⁺-exchanger 1 (NHE-1) and activated AKT kinase and endothelial NO synthase (eNOS) pathways to ameliorate ALDH2*2-induced EC dysfunction. Together, our results suggest that ALDH2*2 induces EC dysfunction and that SGLT2i may potentially be used as a preventative measure against CAD for ALDH2*2 carriers.

Plausible Role of NLRP3 Inflammasome and Associated Cytokines in Pathogenesis of Rheumatic Heart Disease

Rheumatic heart disease (RHD) is a post-streptococcal sequela caused by Streptococcus pyogenes. The global burden of disease is high among people with low socio-economic status, with significant cases emerging every year despite global eradication efforts. The current treatment includes antibiotic therapies to target strep throat and rheumatic fever and valve replacement strategies as a corrective measure for chronic RHD patients. Valvular damage and valve calcification are considered to be the end-stage processes of the disease resulting from impairment of the endothelial arrangement due to immune infiltration. This immune infiltration is mediated by a cascade of events involving NLRP3 inflammasome activation. NLRP3 inflammasome is activated by wide range of stimuli including bacterial cell wall components like M proteins and leukocidal toxins like nicotinamide dehydrogenase (NADase) and streptolysin O (SLO) and these play a major role in sustaining the virulence of Streptococcus pyogenes and progression of RHD. In this review, we are discussing NLRP3 inflammasome and its plausible role in the pathogenesis of RHD by exploiting the host-pathogen interaction mainly focusing on the NLRP3 inflammasome-mediated cytokines IL-1β and IL-18. Different therapeutic approaches involving NLRP3 inflammasome inactivation, caspase-1 inhibition, and blockade of IL-1β and IL-18 are discussed in this review and may be promising for treating RHD patients.

The IL-1 Family and Its Role in Atherosclerosis

The IL-1 superfamily of cytokines is a central regulator of immunity and inflammation. The family is composed of 11 cytokines (with agonist, antagonist, and anti-inflammatory properties) and 10 receptors, all tightly regulated through decoy receptor, receptor antagonists, and signaling inhibitors. Inflammation not only is an important physiological response against infection and injury but also plays a central role in atherosclerosis development. Several clinical association studies along with experimental studies have implicated the IL-1 superfamily of cytokines and its receptors in the pathogenesis of cardiovascular disease. Here, we summarize the key features of the IL-1 family, its role in immunity and disease, and how it helps shape the development of atherosclerosis.

The Mutual Contribution of 3-NT, IL-18, Albumin, and Phosphate Foreshadows Death of Hemodialyzed Patients in a 2-Year Follow-Up

Patients with chronic kidney disease (CKD), especially those who are hemodialyzed (HD), are at significantly high risk of contracting cardiovascular disease and having increased mortality. This study aimed to find potential death predictors, the measurement of which may reflect increased mortality in HD patients, and then combine the most promising ones in frames of a simple death risk assessment model. For this purpose, HD patients (n=71) with acute myocardial infarction in the last year (HD group) and healthy people (control group) as a comparative group (n=32) were included in the study. Various laboratory determinations and non-invasive cardiovascular tests were performed. Next, patients were followed for two years, and data on cardiovascular (CV) deaths were collected. On this basis, two HD groups were formed: patients who survived (HD-A, n=51) and patients who died (HD-D, n=20). To model HD mortality, 21 out of 90 potential variables collected or calculated from the raw data were selected. The best explanatory power (95.5%) was reached by a general linear model with four variables: interleukin 18, 3-nitrotyrosine, albumin, and phosphate. The interplay between immuno-inflammatory processes, nitrosative and oxidative stress, malnutrition, and calcium-phosphate disorders has been indicated to be essential in predicting CV-related mortality in studied HD patients. ClinicalTrials.gov Identifier: NCT05214872.

Inflammation and the Link to Vascular Brain Health: Timing Is Brain

Inflammation and its myriad pathways are now recognized to play both causal and consequential roles in vascular brain health. From acting as a trigger for vascular brain injury, as evidenced by the coronavirus disease 2019 (COVID-19) pandemic, to steadily increasing the risk for chronic cerebrovascular disease, distinct inflammatory cascades play differential roles in varying states of cerebrovascular injury. New evidence is regularly emerging that characterizes the role of specific inflammatory pathways in these varying states including those at risk for stroke and chronic cerebrovascular injury as well as during the acute, subacute, and repair phases of stroke. Here, we aim to highlight recent basic science and clinical evidence for many distinct inflammatory cascades active in these varying states of cerebrovascular injury. The role of cerebrovascular infections, spotlighted by the severe acute respiratory syndrome coronavirus 2 pandemic, and its association with increased stroke risk is also reviewed. Rather than converging on a shared mechanism, these emerging studies implicate varied and distinct inflammatory processes in vascular brain injury and repair. Recognition of the phasic nature of inflammatory cascades on varying states of cerebrovascular disease is likely essential to the development and implementation of an anti-inflammatory strategy in the prevention, treatment, and repair of vascular brain injury. Although advances in revascularization have taught us that time is brain, targeting inflammation for the treatment of cerebrovascular disease will undoubtedly show us that timing is brain.

Sustained inflammation, coagulation activation and elevated endothelin-1 levels without macrovascular dysfunction at 3 months after COVID-19

INTRODUCTION

Endothelial damage and thrombosis caused by COVID-19 may imperil cardiovascular health. More than a year since the WHO declared COVID-19 pandemic, information on its effects beyond the acute phase is lacking. We investigate endothelial dysfunction, coagulation and inflammation, 3 months post-COVID-19.

MATERIALS AND METHODS

A cohort study was conducted including 203 patients with prior COVID-19. Macrovascular dysfunction was assessed by measuring the carotid artery diameter in response to hand immersion in ice-water. A historic cohort of 312 subjects served as controls. Propensity score matching corrected for baseline differences. Plasma concentrations of endothelin-1 were measured in patients post-COVID-19, during the acute phase, and in matched controls. Coagulation enzyme:inhibitor complexes and inflammatory cytokines were studied.

RESULTS AND CONCLUSIONS

The prevalence of macrovascular dysfunction did not differ between the COVID-19 (18.6%) and the historic cohort (22.5%, RD -4%, 95%CI: -15-7, p = 0.49). Endothelin-1 levels were significantly higher in acute COVID-19 (1.67 ± 0.64 pg/mL) as compared to controls (1.24 ± 0.37, p < 0.001), and further elevated 3 months post-COVID-19 (2.74 ± 1.81, p < 0.001). Thrombin:antithrombin(AT) was high in 48.3%. Markers of contact activation were increased in 16-30%. FVIIa:AT (35%) and Von Willebrand Factor:antigen (80.8%) were elevated. Inflammatory cytokine levels were high in a majority: interleukin(IL)-18 (73.9%), IL-6 (47.7%), and IL-1ra (48.9%). At 3 months after acute COVID-19 there was no indication of macrovascular dysfunction; there was evidence, however, of sustained endothelial cell involvement, coagulation activity and inflammation. Our data highlight the importance of further studies on SARS-CoV-2 related vascular inflammation and thrombosis, as well as longer follow-up in recovered patients.

Roles of Macrophages in Atherogenesis

Atherosclerosis is a chronic inflammatory disease that may ultimately lead to local proteolysis, plaque rupture, and thrombotic vascular disease, resulting in myocardial infarction, stroke, and sudden cardiac death. Circulating monocytes are recruited to the arterial wall in response to inflammatory insults and differentiate into macrophages which make a critical contribution to tissue damage, wound healing, and also regression of atherosclerotic lesions. Within plaques, macrophages take up aggregated lipoproteins which have entered the vessel wall to give rise to cholesterol-engorged foam cells. Also, the macrophage phenotype is influenced by various stimuli which affect their polarization, efferocytosis, proliferation, and apoptosis. The heterogeneity of macrophages in lesions has recently been addressed by single-cell sequencing techniques. This article reviews recent advances regarding the roles of macrophages in different stages of disease pathogenesis from initiation to advanced atherosclerosis. Macrophage-based therapies for atherosclerosis management are also described.

Serum interleukin-18 and its relationship with subclinical atherosclerosis in systemic lupus erythematosus

BACKGROUND

Interleukin-18 (IL-18) is a pro-inflammatory and pro-atherogenic factor, and its blood level has shown a direct correlation with atherosclerosis. We aimed to evaluate the serum IL-18 level in patients with systemic lupus erythematosus (SLE) and its relationship with the intima-media thickness (IMT) of the carotid artery in these patients, as an indicator of atherosclerosis.

METHODS

In this cross-sectional study, 60 patients as the patient group and 30 healthy volunteers as the control group [matched sex, age, and body mass index (BMI)] were selected, and their disease status and general data were gathered using the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) form. A blood sample was also obtained from all participants to determine the serum level of IL-18 and other metrics, including high-sensitivity C-reactive protein (hs-CRP), cholesterol, triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), anti-double stranded deoxyribonucleic acid (anti-dsDNA), complement 3 (C3), and C4. The IMT of the carotid artery was calculated in both groups. We also evaluated the clinical cardiovascular manifestations.

RESULTS

The serum IL-18 levels in patients were significantly higher than in the control group (P ˂ 0.005). It had no significant correlation with disease activity (P = 0.10). The patients with SLE with high IL-18 serum levels (> 280 pg/ml) had higher SLEDAI-2K (P = 0.02) than the patients with a low level (< 280), where 280 was the median of the IL-18 levels. The serum IL-18 level had no significant correlation with the carotid artery IMT.

CONCLUSION

A high level of IL-18 reflects the disease activity, but it was not significantly correlated with subclinical atherosclerosis, denoted by the carotid artery IMT.

Genotyping of interleukins-18 promoters and their correlation with coronary artery stenosis in Saudi population

BACKGROUND

Complex coronary atherosclerotic lesions often lead to coronary occlusion, clinically represented as a single-vessel disease (SVD) and multivessel disease (MVD). These occlusions could hinder the blood flow in coronary arteries that affects appropriate management of the CVD. The current study intended to genotype interleukin (IL)-18 promoter's hotspots (rs187238, rs1946518, and rs1946519) and their possible association with coronary artery stenosis.

MATERIAL AND METHODS

The IL-18 promoter genotyping was performed by the Sanger method along with the examination of biochemical parameters in 125 study subjects categorized into three groups, viz. controls, SVD and MVD.

RESULTS

The current study observed a significant association of diabetes, hypertension, and dyslipidemia between the studied group's viz. healthy controls, SVD, and MVD. Fasting blood sugar and glycosylated hemoglobin (HBA1C) were also significantly enhanced from 4.82 vs. 8.01 and 4.33 vs. 8.27, in SVD, and MVD respectively. Despite the visible differences in the pattern of genotypic and allelic expressions, the current study did not show any statistically significant correlation with IL-18 promoter polymorphism at its hotspots with controls, SVD, and MVD subjects. The only exception of the above results was the distribution of allelic frequency at the rs1946519 hotspot, where a significant change (P < 0.05) was observed.

CONCLUSION

This study is of additional value to our previous reports, revealing the pattern of genotypes and allelic frequency of IL-18 promoters in a small cohort of Saudi ethnicity. Further investigations on larger sample size are recommended to envisage the presence of functional mutations in the IL-18 gene that could establish or rule out the possible association of IL-18 polymorphism with SVD and MVD.

Anti-Inflammatory Drugs in Patients with Ischemic Heart Disease

Inflammation has long been known to play a role in atherogenesis and plaque complication, as well as in some drugs used in therapy for atherosclerotic disease, such as statins, acetylsalicylic acid, and modulators of the renin-angiotensin system, which also have anti-inflammatory effects. Furthermore, inflammatory biomarkers have been demonstrated to predict the incidence of cardiovascular events. In spite of this, and with the exception of acetylsalicylic acid, non-steroidal anti-inflammatory drugs are unable to decrease the incidence of cardiovascular events and may even be harmful to the cardiovascular system. In recent years, other anti-inflammatory drugs, such as canakinumab and colchicine, have shown an ability to reduce the incidence of cardiovascular events in secondary prevention. Colchicine could be a potential candidate for use in clinical practice given its safety and low price, although the results of temporary studies require confirmation in large randomized clinical trials. In this paper, we discuss the evidence linking inflammation with atherosclerosis and review the results from various clinical trials performed with anti-inflammatory drugs. We also discuss the potential use of these drugs in routine clinical settings.

Discerning the promising binding sites of S100/calgranulins and their therapeutic potential in atherosclerosis

INTRODUCTION

Atherosclerosis is a chronic inflammatory disease in which the members of S100 family proteins (calgranulins) bind with their receptors, particularly receptor for advanced glycation end products (RAGE) and toll-like receptor-4 (TLR-4) and play a key role in the pathogenesis and progression of disease. Thus, these proteins could be considered as potential biomarkers and therapeutic targets in the treatment of atherosclerotic inflammation.

AREAS COVERED

This review summarizes the pathology of S100A8, S100A9, and S100A12 in the development of atherosclerosis and reveals key structural features of these proteins which are potentially critical in their pathological effects. This article focuses on the translational significance of antagonizing these proteins by using small molecules in patent literature, clinical and preclinical studies and also discusses future approaches that could be employed to block these proteins in the treatment of atherosclerosis.

EXPERT OPINION

Based on the critical role of S100/calgranulins in the regulation of atherosclerosis, these proteins are potential targets to develop better therapeutic options in the treatment of inflammatory diseases. However, further research is still needed to clarify their exact molecular mechanism by analyzing their detailed structural features that can expedite future research to develop novel therapeutics against these proteins to treat atherosclerotic inflammation.

Evaluation of Blood Coagulation Parameters and ADMA, NO, IL-6, and IL-18 Serum Levels in Patients with Neovascular AMD before, during, and after the Initial Loading Phase of Intravitreal Aflibercept

We evaluated the effect of intravitreal injections of aflibercept (IVA) on blood coagulation parameters including prothrombin time (PT), activated partial thromboplastin time (APTT), and thrombin time (TT), as well as asymmetric dimethylarginine (ADMA), nitric oxide (NO), interleukin 6 (IL-6), and interleukin 18 (IL-18) serum levels in patients with neovascular AMD (nAMD). Twenty-two eyes of 22 patients with nAMD were included. Parameters were evaluated before and 2–3 days after the first IVA injection, and then immediately before and 2–3 days after the third IVA injection. We revealed prolongation of the TT after the initial loading phase of IVA (p = 0.041) and a significant increase in IL-18 serum concentration immediately before the third IVA administration compared to baseline (p = 0.037). There were no statistically significant differences of other parameters and PT, APTT, ADMA, NO, and IL-6 values remained within the normal range at each of the time points of the study. Our results suggest that repeated IVA administration may affect the common blood coagulation pathway, which manifests as a prolongation of the TT value. Furthermore, we showed a significant increase in serum concentration of the pro-inflammatory cytokineIL-18during the initial loading phase of IVA.

Endothelial Dysfunction, Inflammation and Coronary Artery Disease: Potential Biomarkers and Promising Therapeutical Approaches

Coronary artery disease (CAD) and its complications are the leading cause of death worldwide. Inflammatory activation and dysfunction of the endothelium are key events in the development and pathophysiology of atherosclerosis and are associated with an elevated risk of cardiovascular events. There is great interest to further understand the pathophysiologic mechanisms underlying endothelial dysfunction and atherosclerosis progression, and to identify novel biomarkers and therapeutic strategies to prevent endothelial dysfunction, atherosclerosis and to reduce the risk of developing CAD and its complications. The use of liquid biopsies and new molecular biology techniques have allowed the identification of a growing list of molecular and cellular markers of endothelial dysfunction, which have provided insight on the molecular basis of atherosclerosis and are potential biomarkers and therapeutic targets for the prevention and or treatment of atherosclerosis and CAD. This review describes recent information on normal vascular endothelium function, as well as traditional and novel potential biomarkers of endothelial dysfunction and inflammation, and pharmacological and non-pharmacological therapeutic strategies aimed to protect the endothelium or reverse endothelial damage, as a preventive treatment for CAD and related complications.

The Assessment of Interleukin-18 on the Risk of Coronary Heart Disease

BACKGROUND

Observational studies support the inflammation hypothesis in coronary heart disease (CHD). As a pleiotropic proinflammatory cytokine, Interleukin-18 (IL-18), has also been found to be associated with the risk of CHD. However, to our knowledge, the method of Mendelian Randomization has not been used to explore the causal effect of IL-18 on CHD.

OBJECTIVE

To assess the causal effect of IL-18 on the risk of CHD.

METHODS AND RESULTS

Genetic variant instruments for IL-18 were obtained from information of the CHS and InCHIANTI cohort, and consisted of the per-allele difference in mean IL-18 for 16 independent variants that reached genome-wide significance. The per-allele difference in log-odds of CHD for each of these variants was estimated from CARDIoGRAMplusC4D, a two-stage meta -analysis. Two-sample Mendelian Randomization (MR) was then performed. Various MR analyses were used, including weighted inverse-variance, MR-Egger regression, robust regression, and penalized regression. The OR of elevated IL-18 associated with CHD was only 0.005 (95%CI -0.105~0.095; P-value=0.927). Similar results were obtained with the use of MR-Egger regression, suggesting that directional pleiotropy was unlikely biasing these results (intercept -0.050, P-value=0.220). Moreover, results from the robust regression and penalized regression analyses also revealed essentially similar findings.

CONCLUSION

Our findings indicate that, by itself, IL-18 is unlikely to represent even a modest causal factor for CHD risk.

Serum interleukin-18 levels are associated with non-dipping pattern in newly diagnosed hypertensive patients

BACKGROUND

Interleukin-18 (IL-18), a pro-inflammatory cytokine, increases inflammation in the endothelium. Increased inflammation plays an important role in the development of hypertension (HT). IL-18 level is higher in hypertensives than normotensives.

OBJECTIVE

To investigate the relationship between IL-18 level and diurnal blood pressure (BP) variations in newly diagnosed HT patients.

METHODS

This prospective study included 130 subjects referred to outpatient cardiology clinic with an initial diagnosis of HT. The patients were classified as dipper HT (n = 40), non-dipper HT (n = 50), and normotensive (control, n = 40) according to 24-hour ambulatory BP monitoring. All subjects underwent blood sampling after 12 hours of fasting and transthoracic echocardiography.

RESULTS

The serum IL-18 level was significantly higher in the patient group compared with the controls (195.17 ± 93.00 mg/dl vs. 140.75 ± 71.11 mg/dl, P < 0.01) and also in the non-dipper group than in the dipper group (217.3 ± 96.90 mg/dl, 167.5 ± 80.79 mg/dl, P = 0.011). IL-18 level was positively correlated both the night-time SBP and DBP levels (r = 0.29, P = 0.02 and r = 0.34, P < 0.01, respectively). On multivariate linear regression analysis, left atrium diameter, left ventricular mass index, and serum IL-18 level were independent predictors of non-dipping pattern in newly diagnosed HT patients.

CONCLUSION

Higher IL-18 level was particularly associated with an increase in the night-time BP levels. IL-18 can be used as a predictor for non-dipper HT in newly diagnosed HT patients.

Serum Galectin-3 and Subsequent Risk of Coronary Heart Disease in Subjects With Childhood-Onset Type 1 Diabetes: A Cohort Study

OBJECTIVE

To study whether serum galectin-3 and other biomarkers of inflammation predict coronary heart disease (CHD) in subjects with long-standing childhood-onset type 1 diabetes.

RESEARCH DESIGN AND METHODS

A population-based nationwide cohort of 299 subjects with type 1 diabetes diagnosed in Norway at <15 years of age during 1973-1982 was examined in 2002-2003 at a mean age of 33 years (range 21-44), with mean diabetes duration of 24 years (range 19-30). Subjects were followed through 31 December 2017 for their first CHD event registered by a hospitalization or cause of death using nationwide registries. Stored serum samples were available for 296 subjects and analyzed for interleukin-6 (IL-6), IL-6 receptor, IL-18, hs-CRP, matrix metalloproteinase-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), galectin-3, and high-sensitivity troponin T. Adjusted hazard ratios (aHRs) for CHD per SD increase in biomarker were estimated using Cox regression.

RESULTS

Of 295 subjects, 40 (13.6%) had a documented CHD event during a mean follow-up of 14.4 years (range 0.5-16). IL-6 (aHR 1.32 [95% CI 1.07-1.63]), galectin-3 (aHR 1.44 [95% CI 1.09-1.80]), and TIMP-1 (aHR 1.37 [95% CI 1.04-1.81]) were significant predictors of CHD after adjustment for conventional risk factors.

CONCLUSIONS

Galectin-3 was significantly associated with future CHD in subjects with type 1 diabetes, and if the results are replicated in larger studies, it may aid in prediction together with conventional risk factors for CHD.

Sacubitril-valsartan improves conduit vessel function and functional capacity and reduces inflammation in heart failure with reduced ejection fraction

The Prospective comparison of ARNI with angiotensin-converting enzyme inhibitor to Determine Impact on Global Mortality and morbidity in Heart Failure trial identified a marked reduction in the risk of death and hospitalization for heart failure in patients with heart failure with reduced ejection fraction (HFrEF) treated with sacubitril-valsartan (trade name Entresto), but the physiological processes underpinning these improvements are unclear. We tested the hypothesis that treatment with sacubitril-valsartan improves peripheral vascular function, functional capacity, and inflammation in patients with HFrEF. We prospectively studied patients with HFrEF (n = 11, 10 M/1 F, left ventricular ejection fraction = 27 ± 8%) on optimal, guideline-directed medical treatment who were subsequently prescribed sacubitril-valsartan (open-label, uncontrolled, and unblinded). Peripheral vascular function [brachial artery flow-mediated dilation (FMD, conduit vessel function) and reactive hyperemia (RH, microvascular function)], functional capacity [six-minute walk test (6MWT) distance], and the proinflammatory biomarkers tumor necrosis factor-α (TNF-α) and interleukin-18 (IL-18) were obtained at baseline and at 1, 2, and 3 mo of treatment. %FMD improved after 1 mo of treatment, and this favorable response persisted for months 2 and 3 (baseline: 3.25 ± 1.75%; 1 mo: 5.23 ± 2.36%; 2 mo: 5.81 ± 1.79%; 3 mo: 6.35 ± 2.77%), whereas RH remained unchanged. 6MWT distance increased at months 2 and 3 (baseline: 420 ± 92 m; 1 mo: 436 ± 98 m; 2 mo: 465 ± 115 m; 3 mo: 460 ± 110 m), and there was a sustained reduction in TNF-α (baseline: 2.38 ± 1.35 pg/mL; 1 mo: 2.06 ± 1.52 pg/mL; 2 mo: 1.95 ± 1.34 pg/mL; 3 mo: 1.92 ± 1.37 pg/mL) and a reduction in IL-18 at month 3 (baseline: 654 ± 150 pg/mL; 1 mo: 595 ± 140 pg/mL; 2 mo: 601 ± 176 pg/mL; 3 mo: 571 ± 127 pg/mL). This study provides new evidence for the potential of this new drug class to improve conduit vessel function, functional capacity, and inflammation in patients with HFrEF.NEW & NOTEWORTHY We observed an approximately twofold improvement in conduit vessel function (brachial artery FMD), increased functional capacity (6MWT distance), and a reduction in inflammation (TNF-α and IL-18) following 3 mo of sacubitril-valsartan therapy. These findings provide important new information concerning the physiological mechanisms by which this new drug class provokes favorable changes in HFrEF pathophysiology.

Combination Treatment with Sodium Nitrite and Isoquercetin on Endothelial Dysfunction among Patients with CKD: A Randomized Phase 2 Pilot Trial

BACKGROUND AND OBJECTIVES

Endothelial dysfunction is common among patients with CKD. We tested the efficacy and safety of combination treatment with sodium nitrite and isoquercetin on biomarkers of endothelial dysfunction in patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This randomized, double-blind, placebo-controlled phase 2 pilot trial enrolled 70 patients with predialysis CKD. Thirty-five were randomly assigned to combination treatment with sodium nitrite (40 mg twice daily) and isoquercetin (225 mg once daily) for 12 weeks, and 35 were randomly assigned to placebo. The primary outcome was mean change in flow-mediated vasodilation over the 12-week intervention. Secondary and safety outcomes included biomarkers of endothelial dysfunction, inflammation, and oxidative stress as well as kidney function, methemoglobin, and adverse events. Intention-to-treat analysis was conducted.

RESULTS

Baseline characteristics, including age, sex, race, cigarette smoking, history of hypertension and diabetes, use of renin-angiotensin system blockers, BP, fasting glucose, lipid profile, kidney function, urine albumin-creatinine ratio, and endothelial biomarkers, were comparable between groups. Over the 12-week intervention, flow-mediated vasodilation increased 1.1% (95% confidence interval, -0.1 to 2.3) in the treatment group and 0.3% (95% confidence interval, -0.9 to 1.5) in the placebo group, and net change was 0.8% (95% confidence interval, -0.9 to 2.5). In addition, changes in biomarkers of endothelial dysfunction (vascular adhesion molecule-1, intercellular adhesion molecule-1, E-selectin, vWf, endostatin, and asymmetric dimethylarginine), inflammation (TNF-α, IL-6, C-reactive protein, IL-1 receptor antagonist, and monocyte chemoattractant protein-1), and oxidative stress (oxidized LDL and nitrotyrosines) were not significantly different between the two groups. Furthermore, changes in eGFR, urine albumin-creatinine ratio, methemoglobin, and adverse events were not significantly different between groups.

CONCLUSIONS

This randomized phase 2 pilot trial suggests that combination treatment with sodium nitrite and isoquercetin did not significantly improve flow-mediated vasodilation or other endothelial function biomarkers but also did not increase adverse events compared with placebo among patients with CKD.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Nitrite, Isoquercetin, and Endothelial Dysfunction (NICE), NCT02552888.

Interactions Between Therapeutics for Metabolic Disease, Cardiovascular Risk Factors, and Gut Microbiota

With improved standards of living, the incidence of multiple metabolic disorders has increased year by year, especially major risk factors for cardiovascular disease such as hyperglycemia and hyperlipidemia, continues to increase. Emerging epidemiological data and clinical trials have shown the additional protective effects of some metabolic therapy drugs against cardiovascular diseases. A series of studies have found that these drugs may work by modulating the composition of gut microbiota. In this review, we provide a brief overview of the contribution of the gut microbiota to both metabolic disorders and cardiovascular diseases, as well as the response of gut microbiota to metabolic therapy drugs with cardiovascular benefits. In this manner, we link the recent advances in microbiome studies on metabolic treatment drugs with their cardiovascular protective effects, suggesting that intestinal microorganisms may play a potential role in reducing cardiovascular risk factors. We also discuss the potential of microorganism-targeted therapeutics as treatment strategies for preventing and/or treating cardiovascular disease and highlight the need to establish causal links between therapeutics for metabolic diseases, gut microbiota modulation, and cardiovascular protection.

Association between polymorphisms in interleukin-18 promoter and risk of coronary artery disease: a meta-analysis

Background: Previous studies have explored associations between interleukin-18 (IL-18) promoter polymorphisms and coronary artery disease (CAD). However, the results were controversial. We conducted a meta-analysis to clarify the association between the two polymorphisms and CAD risk. Methods: We searched English and Chinese databases and calculated the odds ratio (OR) and 95% confidence interval (CI) to estimate whether there are genetic associations between IL-18 promoter polymorphisms and the risk of CAD. All relevant studies were screened and meta-analyzed using STATA 15.0. Results: A total of 15 studies, including 12 studies for -137 G/C and 9 studies for -607 C/A, were identified for the meta-analysis. For -137 G/C, the results showed a significantly reduced risk of CAD in the dominant model (OR = 0.85) and heterozygous model (OR = 0.88) in the overall analysis. However, in subgroup analysis, decreased CAD risks were only observed in Asian populations for heterozygous genetic models. For -607 C/A, the overall OR revealed a reduced risk of CAD in all five genetic models (allelic, OR = 0.78; recessive, OR = 0.75; dominant, OR = 0.68; homozygous, OR = 0.61; heterozygous, OR = 0.72). In subgroup analysis, reduced CAD risk was also found in five genetic models of the Asian population. We also found that the IL-18 polymorphisms were correlated with myocardial infarction (MI) and multivessel (MV) disease. Conclusion: Our results suggested that the -137 polymorphism and -607 polymorphism in the IL-18 promoter were negatively associated with CAD, especially in the Asian population. In addition, some genetic models were correlated with the severity of CAD.

Associations of a vegan diet with inflammatory biomarkers

Vegetarian or vegan nutrition might influence inflammatory processes, thereby reducing the risk of chronic diseases. As the vegan diet becomes more importance in modern societies, data from the “Risks and Benefits of a Vegan Diet”-study has been used to investigate the associations of veganism with a comprehensive spectrum of inflammatory biomarkers, compared to omnivores. This cross-sectional study comprises 36 vegans and 36 omnivores (18 men and 18 women each) aged 30–60 years. No significant differences in any of the investigated inflammatory biomarkers (high-sensitivity C-reactive protein (hsCRP), interleukin-18 (IL-18), interleukin-1 receptor antagonist (IL-1 RA), intercellular adhesion molecule-1 (ICAM-1), adiponectin, omentin-1 and resistin) were observed between vegans and omnivores. However, the duration of a vegan diet was positively correlated with resistin (Spearman r = 0.59), IL-18 concentrations (Spearman r = 0.44) and IL-1 RA (Spearman r = 0.34). Moreover, the present study supports BMI and waist circumference as important factors influencing the inflammatory state. Further research is needed to evaluate associations between a vegan diet and inflammatory biomarkers to provide more evidence about the inflammatory state as underlying mechanisms of a vegan diet to influence the risk of numerous chronic diseases.

An IL-18-centered inflammatory network as a biomarker for cerebral white matter injury

Chronic systemic sterile inflammation is implicated in the pathogenesis of cerebrovascular disease and white matter injury. Non-invasive blood markers for risk stratification and dissection of inflammatory molecular substrates in vivo are lacking. We sought to identify whether an interconnected network of inflammatory biomarkers centered on IL-18 and all previously associated with white matter lesions could detect overt and antecedent white matter changes in two populations at risk for cerebral small vessel disease. In a cohort of 167 older adults (mean age: 76, SD 7.1, 83 females) that completed a cognitive battery, physical examination, and blood draw in parallel with MR imaging including DTI, we measured cerebral white matter hyperintensities (WMH) and free water (FW). Concurrently, serum levels of a biologic network of inflammation molecules including MPO, GDF-15, RAGE, ST2, IL-18, and MCP-1 were measured. The ability of a log-transformed population mean-adjusted inflammatory composite score (ICS) to associate with MR variables was demonstrated in an age and total intracranial volume adjusted model. In this cohort, ICS was significantly associated with WMH (β = 0.222, p = 0.013), FW (β = 0.3, p = 0.01), and with the number of vascular risk factor diagnoses (r = 0.36, p<0.001). In a second cohort of 131 subjects presenting for the evaluation of acute neurologic deficits concerning for stroke, we used serum levels of 11 inflammatory biomarkers in an unbiased principal component analysis which identified a single factor significantly associated with WMH. This single factor was strongly correlated with the six component ICS identified in the first cohort and was associated with WMH in a generalized linear regression model adjusted for age and gender (p = 0.027) but not acute stroke. A network of inflammatory molecules driven by IL-18 is associated with overt and antecedent white matter injury resulting from cerebrovascular disease and may be a promising peripheral biomarker for vascular white matter injury.

Quartz Dust Exposure Affects NLRP3 Inflammasome Activation and Plasma Levels of IL-18 and IL-1Ra in Iron Foundry Workers

Purpose

To study the association between inhalation of particulate matter or quartz in Swedish iron foundries and the effects on NLRP3 inflammasome activation.

Methods

Particle exposure measurements were performed during an eight-hour work day for 85 foundry workers at three Swedish iron foundries. Personal sampling was used for measurement of respirable quartz and dust and stationary measurements to obtain exposure measurements for inhalable dust and PM₁₀. The NLRP3 inflammasome markers, interleukin- (IL-) 1β and IL-18, and inhibitors IL-1 receptor antagonist (IL-1Ra) and IL-18 binding protein (IL-18BP) were measured in plasma. Inflammasome activation was measured by caspase-1 enzymatic activity in monocytes in whole blood by flow cytometry, and expression of inflammasome-related genes was quantified using real-time PCR. Multiple linear regression analysis was used to investigate associations between PM exposures and inflammatory markers. Sex, age, smoking, current infection, BMI, and single nucleotide polymorphism in the inflammasome regulating genes CARD8 (C10X) and NLRP3 (Q705K) were included as covariates.

Results

The average exposure levels of respirable dust and quartz were 0.85 and 0.052 mg/m³, respectively. A significant exposure-response was found for respirable dust and IL-18 and for inhalable dust and IL-1Ra. Whole blood, drawn from study participants, was stimulated ex vivo with inflammasome priming stimuli LPS or Pam3CSK4, resulting in a 47% and 49% increase in caspase-1 enzymatic activity in monocytes. This increase in caspase-1 activity was significantly attenuated in the higher exposure groups for most PM exposure measures.

Conclusions

The results indicate that exposure levels of PM in the iron foundry environment can affect the NLRP3 inflammasome and systemic inflammation.

Targeting Early Atherosclerosis: A Focus on Oxidative Stress and Inflammation

Atherosclerosis is a chronic vascular inflammatory disease associated to oxidative stress and endothelial dysfunction. Oxidation of low-density lipoprotein (LDL) cholesterol is one of the key factors for the development of atherosclerosis. Nonoxidized LDL have a low affinity for macrophages, so they are not themselves a risk factor. However, lowering LDL levels is a common clinical practice to reduce oxidation and the risk of major events in patients with cardiovascular diseases (CVD). Atherosclerosis starts with dysfunctional changes in the endothelium induced by disturbed shear stress which can lead to endothelial and platelet activation, adhesion of monocytes on the activated endothelium, and differentiation into proinflammatory macrophages, which increase the uptake of oxidized LDL (oxLDL) and turn into foam cells, exacerbating the inflammatory signalling. The atherosclerotic process is accelerated by a myriad of factors, such as the release of inflammatory chemokines and cytokines, the generation of reactive oxygen species (ROS), growth factors, and the proliferation of vascular smooth muscle cells. Inflammation and immunity are key factors for the development and complications of atherosclerosis, and therefore, the whole atherosclerotic process is a target for diagnosis and treatment. In this review, we focus on early stages of the disease and we address both biomarkers and therapeutic approaches currently available and under research.

Asymmetric dimethylarginine serum levels are associated with early mortality after allogeneic stem cell transplantation

Increasing evidence suggests that endothelial cell distress is associated with mortality after allogeneic stem cell transplantation and acute graft-versus-host disease. Asymmetric dimethylarginine is an endogenous nitric oxide synthase inhibitor that induces endothelial cell dysfunction. We analyzed the impact of pre-transplant serum levels of asymmetric dimethylarginine on outcome after allogeneic stem cell transplantation. Since acute graft-versus-host disease and its treatment are major contributors to post-transplant mortality, the effect of asymmetric dimethylarginine on outcome measures was also assessed after onset of acute graft-versus-host disease. A total of 938 patients allografted at two centers between 2002 and 2013 were included in the retrospective study. In multivariable models, higher pre-transplant asymmetric dimethylarginine levels were significantly associated with an increased risk of non-relapse mortality (hazard ratio 1.43 per 1-log2 increase, P=0.005) but not with relapse (hazard ratio 1.21, P=0.109) within the first year after transplantation. This translated into worse overall survival (hazard ratio 1.45, P<0.0001) and shorter progression-free survival (hazard ratio 1.30, P=0.002) in the first year after transplantation. Higher pre-transplant asymmetric dimethylarginine levels were also associated with shorter overall survival (hazard ratio 1.46, P=0.001) and progression-free survival (hazard ratio 1.32, P=0.010) and higher non-relapse mortality (hazard ratio 1.36, P=0.042) within 1 year after the onset of acute graft-versus-host disease. Taken together, our data indicate an association between pre-transplant asymmetric dimethylarginine status and early non-relapse mortality in allografted patients, both overall and after the onset of acute graft-versus-host disease. These findings underline the relevance of endothelial dysfunction for transplant complications.

Dynamic Profile of CD4+ T-Cell-Associated Cytokines/Chemokines following Murine Myocardial Infarction/Reperfusion

CD4+ T-cells play crucial roles in the injured heart. However, the way in which different CD4+ T subtypes function in the myocardial infarction/reperfusion (MI/R) heart is still poorly understood. We aimed to detect the dynamic profile of distinct CD4+ subpopulation-associated cytokines/chemokines by relying on a closed-chest acute murine MI/R model. The protein levels of 26 CD4+ T-cell-associated cytokines/chemokines were detected in the heart tissues and serum of mice at day 7 and day 14 post-MI/R or sham surgery. The mRNA levels of IL-4, IL-6, IL-13, IL-27, MIP-1β, MCP-3, and GRO-α were measured in blood mononuclear cells. The protein levels of IL-4, IL-6, IL-13, IL-27, MIP-1β, MCP-3, and GRO-α increased in both injured heart tissues and serum, while IFN-γ, IL-12P70, IL-2, IL-1β, IL-18, TNF-α, IL-5, IL-9, IL-17A, IL-23, IL-10, eotaxin, MIP-1α, RANTES, MCP-1, and MIP-2 increased only in MI/R heart tissues in the day 7 and day 14 groups compared to the sham group. In serum, the IFN-γ, IL-23, and IL-10 levels were downregulated in the MI/R model at both day 7 and day 14 compared to the sham. Compared with the protein expressions in injured heart tissues at day 7, IFN-γ, IL-12P70, IL-2, IL-18, TNF-α, IL-6, IL-4, IL-5, IL-9, IL-17A, IL-23, IL-27, IL-10, eotaxin, IP-10, RANTES, MCP-1, MCP-3, and GRO-α were reduced, while IL-1β and MIP-2 were elevated at day 14. IL-13 and MIP-1β showed higher levels in the MI/R serum at day 14 than at day 7. mRNA levels of IL-4, IL-6, IL-13, and IL-27 were increased in the day 7 group compared to the sham, while MIP-1β, MCP-3, and GRO-α mRNA levels showed no significant difference between the MI/R and sham groups in blood mononuclear cells. Multiple CD4+ T-cell-associated cytokines/chemokines were upregulated in the MI/R hearts at the chronic stage. These results provided important evidence necessary for developing future immunomodulatory therapies after MI/R.

Interleukin-18 in Health and Disease

Interleukin (IL)-18 was originally discovered as a factor that enhanced IFN-γ production from anti-CD3-stimulated Th1 cells, especially in the presence of IL-12. Upon stimulation with Ag plus IL-12, naïve T cells develop into IL-18 receptor (IL-18R) expressing Th1 cells, which increase IFN-γ production in response to IL-18 stimulation. Therefore, IL-12 is a commitment factor that induces the development of Th1 cells. In contrast, IL-18 is a proinflammatory cytokine that facilitates type 1 responses. However, IL-18 without IL-12 but with IL-2, stimulates NK cells, CD4⁺ NKT cells, and established Th1 cells, to produce IL-3, IL-9, and IL-13. Furthermore, together with IL-3, IL-18 stimulates mast cells and basophils to produce IL-4, IL-13, and chemical mediators such as histamine. Therefore, IL-18 is a cytokine that stimulates various cell types and has pleiotropic functions. IL-18 is a member of the IL-1 family of cytokines. IL-18 demonstrates a unique function by binding to a specific receptor expressed on various types of cells. In this review article, we will focus on the unique features of IL-18 in health and disease in experimental animals and humans.

Developmental trajectories of body mass index from childhood into late adolescence and subsequent late adolescence-young adulthood cardiometabolic risk markers

Background

Reports on body mass index (BMI) trajectories from childhood into late adolescence, their determinants, and subsequent cardiometabolic risk markers, particularly among European populations have been few. Moreover, sex-specific investigation is necessary considering the sex difference in BMI, and the sex-specific association between BMI and some cardiometabolic risk markers.

Methods

Using a sample from the DOrtmund Nutritional and Anthropometric Longitudinally Designed study, we explored sex-specific trajectories of the BMI standard deviation score (SDS) from 4 to 18 years of age in 354 males and 335 females by latent (class) growth models. The determinants of trajectory were assessed by logistic regression. We identified cardiometabolic risk markers that were highly associated with BMI SDS trajectory by random forest regression, and finally we used generalized linear models to investigate differences in the identified cardiometabolic risk markers between pairs of trajectories.

Results

We observed four: ‘low-normal weight’, ‘mid-normal weight’, ‘high-normal weight’, and ‘overweight’, and three: ‘‘low-normal weight’, ‘mid-normal weight’, and ‘high-normal weight’ trajectories in males and females, respectively. Higher maternal prepregnancy BMI was associated with the ‘overweight’ trajectory, and with ‘high-normal weight’ trajectory in both sexes. In addition, employed mothers and first-born status were associated with ‘high-normal weight’ trajectory in females. BMI SDS trajectory was associated with high-density lipoprotein-cholesterol and interleukin-18 (IL-18) in males, and diastolic blood pressure and interleukin-6 (IL-6) in females. However, only males following the ‘overweight’ trajectory had significantly higher IL-18 when compared to their ‘low-normal weight’ counterpart.

Conclusions

We identified sex-specific distinct trajectories of BMI SDS from childhood into late adolescence, higher maternal prepregnancy BMI as a common determinant of the ‘high-normal weight’ and ‘overweight’ trajectories, and ‘overweight’ trajectory being associated with elevated IL-18 in late adolescence–young adulthood. This study emphasizes the role of maternal prepregnancy BMI in overweight, and highlights IL-18 as a cardiometabolic signature of overweight across life.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0813-5) contains supplementary material, which is available to authorized users.

Shrunken Pore Syndrome Is Associated With Increased Levels of Atherosclerosis-Promoting Proteins

INTRODUCTION

Shrunken pore syndrome (SPS), originally defined by cystatin C-based estimated glomerular filtration rate (eGFRcystatin C) being less than 60% of creatinine-based estimated glomerular filtration rate (eGFRcreatinine) in the absence of extrarenal influences on the plasma levels of cystatin C or creatinine, is associated with a high increase in mortality, even in the absence of reduced glomerular filtration rate (GFR). The objective of the present study was to determine whether the proteome of patients with SPS shows differences from that of patients with normal or reduced measured GFR (mGFR) without SPS.

METHODS

Four patient cohorts were included: 1 cohort with normal mGFR without SPS, 1 with normal mGFR with SPS, 1 with reduced mGFR without SPS, and 1 with reduced mGFR with SPS. The plasma levels of 177 selected proteins were analyzed.

RESULTS

Differences in the levels of 30 proteins were specific for SPS; 31 differences were specific for patients with both SPS and reduced mGFR; and 27 were specific for reduced mGFR. Eighteen of the differences specific for SPS concerned proteins described as promoting, or being associated with, atherosclerosis. Twelve of the differences specific for patients with both SPS and reduced mGFR and 10 of the differences specific for reduced mGFR also concerned proteins described as promoting, or being associated with, atherosclerosis. Almost all (82 of 88) of the concentration differences represented increased levels. For SPS, but not for reduced mGFR, a correlation between protein size and increase in level was observed, with smaller proteins being associated with higher levels.

CONCLUSION

The high mortality in shrunken pore syndrome might be caused by the accumulation of atherosclerosis-promoting proteins in this condition.

Persistent metabolic changes in HIV-infected patients during the first year of combination antiretroviral therapy

The HIV-human metabolic relationship is a complex interaction convoluted even more by antiretroviral therapy (cART) and comorbidities. The ability of cART to undo the HIV induced metabolic dysregulation is unclear and under-investigated. Using targeted metabolomics and multiplex immune biomarker analysis, we characterized plasma samples obtained from 18 untreated HIV-1-infected adult patients and compared these to a non-HIV infected (n = 23) control population. The biogenic amine perturbations during an untreated HIV infection implicated altered tryptophan- nitrogen- and muscle metabolism. Furthermore, the lipid profiles of untreated patients were also significantly altered compared to controls. In untreated HIV infection, the sphingomyelins and phospholipids correlated negatively to markers of infection IP-10 and sIL-2R whereas a strong association was found between triglycerides and MCP-1. In a second cohort, we characterized plasma samples obtained from 28 HIV-1-infected adult patients before and 12 months after the start of cART, to investigate the immune-metabolic changes associated with cART. The identified altered immune-metabolic pathways of an untreated HIV infection showed minimal change after 12 months of cART. In conclusion, 12 months of cART impacts only mildly on the metabolic dysregulation underlying an untreated HIV infection and provide insights into the comorbidities present in virally suppressed HIV patients.

Exploring the Clinical Relevance of Providing Increased Removal of Large Middle Molecules

Dialysis technologies have continued to advance over recent decades; however, these advancements have not always been met with improved patient outcomes. In part, the high morbidity and mortality associated with dialysis have been attributed to a group of uremic toxins, which are described as "difficult to remove." With a new generation of hemodialysis membranes now making meaningful clearance of these molecules possible, it is an apt time to review the clinical relevance of these middle molecules. Our review describes the developments in membrane technology that enable the removal of large middle molecules (molecular mass >15 kD) that is limited with high-flux dialysis membranes. Of the known 58 middle molecules, a literature search identified 27 that have molecular mass >15 kD. This group contains cytokines, adipokines, hormones, and other proteins. These molecules are implicated in chronic inflammation, atherosclerosis, structural heart disease, and secondary immunodeficiency in the literature. Single-center safety and efficacy studies have identified that use of these membranes in maintenance dialysis populations is associated with limited loss of albumin and increased clearance of large middle molecules. Larger, robustly conducted, multicenter studies are now evaluating these findings. After completion of these safety and efficacy studies, the perceived clinical benefits of providing clearance of large middle molecules must be assessed in rigorously conducted, randomized clinical studies.

Age and Age-Related Diseases: Role of Inflammation Triggers and Cytokines

Cytokine dysregulation is believed to play a key role in the remodeling of the immune system at older age, with evidence pointing to an inability to fine-control systemic inflammation, which seems to be a marker of unsuccessful aging. This reshaping of cytokine expression pattern, with a progressive tendency toward a pro-inflammatory phenotype has been called "inflamm-aging." Despite research there is no clear understanding about the causes of "inflamm-aging" that underpin most major age-related diseases, including atherosclerosis, diabetes, Alzheimer's disease, rheumatoid arthritis, cancer, and aging itself. While inflammation is part of the normal repair response for healing, and essential in keeping us safe from bacterial and viral infections and noxious environmental agents, not all inflammation is good. When inflammation becomes prolonged and persists, it can become damaging and destructive. Several common molecular pathways have been identified that are associated with both aging and low-grade inflammation. The age-related change in redox balance, the increase in age-related senescent cells, the senescence-associated secretory phenotype (SASP) and the decline in effective autophagy that can trigger the inflammasome, suggest that it may be possible to delay age-related diseases and aging itself by suppressing pro-inflammatory molecular mechanisms or improving the timely resolution of inflammation. Conversely there may be learning from molecular or genetic pathways from long-lived cohorts who exemplify good quality aging. Here, we will discuss some of the current ideas and highlight molecular pathways that appear to contribute to the immune imbalance and the cytokine dysregulation, which is associated with "inflammageing" or parainflammation. Evidence of these findings will be drawn from research in cardiovascular disease, cancer, neurological inflammation and rheumatoid arthritis.

Evaluation of the Role of -137G/C Single Nucleotide Polymorphism (rs187238) and Gene Expression Levels of the IL-18 in Patients with Coronary Artery Disease

Objectives

Interleukin-18 (IL-18) is a proinflammatory and proatherogenic cytokine, and its genetic variations may contribute to the development of coronary artery disease (CAD). We sought to investigate the role of -137G/C polymorphism and gene expression levels of IL-18 in patients with CAD.

Methods

The study population included 100 patients with angiographically proven CAD and 100 matched controls. Total RNA and DNA were extracted from leukocytes using appropriate kits. The genotype of -137G/C polymorphism and gene expression level of IL-18 was determined using allele-specific polymerase chain reaction (PCR) and real-time (RT)-PCR assay, respectively.

Results

The genotypic and allelic distribution of IL-18 -137G/C polymorphism was not significantly different between the two groups (p > 0.050). Moreover, the -137G/C polymorphism did not increase the risk of CAD in dominant and recessive genetic models (p > 0.050). However, subgroup analysis of CAD patients revealed that the IL-18 -137G/C polymorphism was significantly associated with increased risk of CAD in hypertensive patients (odds ratio (OR) = 7.51; 95% confidence interval (CI): 1.24-25.17; p = 0.019) and smokers (OR = 4.90; 95% CI: 1.21-19.70; p = 0.031) but not in the diabetic subpopulation (p = 0.261). The genotype distribution of IL-18 -137G/C genetic polymorphism was significantly different among patients with one, two, and three stenotic vessels (p < 0.050). The gene expression level of IL-18 was significantly higher in the CAD group than the control group (p < 0.001). Moreover, the carriers of CC genotype had significantly lower gene expression levels of IL-18 than carriers of GG genotype (p < 0.050).

Conclusions

The -137G/C polymorphism of IL-18 may be associated with the CAD risk in hypertensive and smoker subgroup of CAD patients. The -137G/C polymorphism seems to play an important role in determining the severity of CAD. Increased IL-18 gene expression level is a significant risk factor for the development of CAD. The CC genotype of -137G/C polymorphism is associated with lower IL-18 gene expression levels.

Increased Expression of Interleukin-18 mRNA is Associated with Carotid Artery Stenosis

Background:

Carotid artery stenosis is the atherosclerotic narrowing of the proximal internal carotid artery and one of the primary causes of stroke. Elevated expression of the pleiotropic proinflammatory cytokine interleukin-18 has been demonstrated in human atherosclerotic plaques.

Aims:

To investigate whether the mRNA expression levels of interleukin-18 and interleukin-18-binding protein and interleukin-18 −137 G/C (rs187238) variants are associated with carotid artery stenosis development.

Study Design:

Case-control study.

Methods:

The mRNA expression levels of interleukin-18 and interleukin-18-binding protein and interleukin-18 rs187238 variants were evaluated by quantitative real-time polymerase chain reaction and real-time polymerase chain reaction, respectively, in the peripheral blood mononuclear cells of 70 patients with carotid artery stenosis (36 symptomatic, 34 asymptomatic) and 75 healthy controls.

Results:

Interleukin-18 mRNA expression was significantly increased in carotid artery stenosis patients compared to that in healthy controls (p=0.01). However, no significant difference was observed between interleukin-18-binding protein mRNA expression levels in patients with carotid artery stenosis and those in controls (p=0.101). Internal carotid artery stenosis severity was significantly higher in symptomatic patients than that in asymptomatic patients (p<0.001). A significant relationship was identified between interleukin-18 expression and internal carotid artery stenosis severity in patients with carotid artery stenosis (p=0.051). Interleukin-18 rs187238 polymorphism genotype frequencies did not significantly differ between patients with carotid artery stenosis and controls (p=0.246). A significant difference was identified between interleukin-18-binding protein gene expression and symptomatic and asymptomatic patients (p=0.026), but there was no difference in interleukin-18 expression between the symptomatic and asymptomatic subgroups (p=0.397).

Conclusion:

Interleukin-18 mRNA expression may affect carotid artery stenosis etiopathogenesis and internal carotid artery stenosis severity and also may play a mechanistic role in the pathogenesis of carotid artery stenosis, influencing the appearance of symptoms.