The interleukin-6 receptor as a target for prevention of coronary heart disease: a mendelian randomisation analysis

Therapeutic targeting of inflammation in hypertension: from novel mechanisms to translational perspective

Both animal models and human observational and genetic studies have shown that immune and inflammatory mechanisms play a key role in hypertension and its complications. We review the effects of immunomodulatory interventions on blood pressure, target organ damage, and cardiovascular risk in humans. In experimental and small clinical studies, both non-specific immunomodulatory approaches, such as mycophenolate mofetil and methotrexate, and medications targeting T and B lymphocytes, such as tacrolimus, cyclosporine, everolimus, and rituximab, lower blood pressure and reduce organ damage. Mechanistically targeted immune interventions include isolevuglandin scavengers to prevent neo-antigen formation, co-stimulation blockade (abatacept, belatacept), and anti-cytokine therapies (e.g. secukinumab, tocilizumab, canakinumab, TNF-α inhibitors). In many studies, trial designs have been complicated by a lack of blood pressure-related endpoints, inclusion of largely normotensive study populations, polypharmacy, and established comorbidities. Among a wide range of interventions reviewed, TNF-α inhibitors have provided the most robust evidence of blood pressure lowering. Treatment of periodontitis also appears to deliver non-pharmacological anti-hypertensive effects. Evidence of immunomodulatory drugs influencing hypertension-mediated organ damage are also discussed. The reviewed animal models, observational studies, and trial data in humans, support the therapeutic potential of immune-targeted therapies in blood pressure lowering and in hypertension-mediated organ damage. Targeted studies are now needed to address their effects on blood pressure in hypertensive individuals.

Systemic effects of IL-6 blockade in rheumatoid arthritis beyond the joints

Interleukin (IL)-6 is produced locally in response to an inflammatory stimulus, and is able to induce systemic manifestations at distance from the site of inflammation. Its unique signaling mechanism, including classical and trans-signaling pathways, leads to a major expansion in the number of cell types responding to IL-6. This pleiotropic cytokine is a key factor in the pathogenesis of rheumatoid arthritis (RA) and is involved in many extra-articular manifestations that accompany the disease. Thus, IL-6 blockade is associated with various biological effects beyond the joints. In this review, the systemic effects of IL-6 in RA comorbidities and the consequences of its blockade will be discussed, including anemia of chronic disease, cardiovascular risks, bone and muscle functions, and neuro-psychological manifestations.

Interleukin 6 trans-signalling and the risk of future cardiovascular events in men and women

Objective

Pro-inflammatory interleukin 6 (IL6) trans-signalling is associated with increased risk of cardiovascular events (CVEs). Whether this association exists for both sexes is, however, uncertain. Hence, we analysed the risk of CVE associated with IL6 trans-signalling in men and women and investigated if potential interaction between IL6 trans-signalling and sex affects the risk.

Methods

In a prospective cohort of 60-year-old men and women without cardiovascular disease (men=2039, women=2193), subjects were followed for 20 years. To assess the IL6 trans-signalling activity, the proportion between the active binary and inactive ternary IL6 complexes, the binary/ternary ratio (B/T ratio), was estimated. CVE (myocardial infarction, angina pectoris and ischaemic stroke, n=629) risk was analysed with Cox regression, presented as HRs with 95% CIs. B/T ratio was dichotomised, with levels >median representing IL6 trans-signalling. Interaction was analysed on the additive scale and expressed as the synergy index (S). Analyses were adjusted for cardiovascular risk factors.

Results

B/T ratio >median was associated with increased CVE risk in men (HR 1.63; 95% CI 1.32 to 2.01), but not in women (HR 1.21; 95% CI 0.93 to 1.57). There was a significant synergistic interaction (S=1.98; 95% CI 1.15 to 3.42) between the B/T ratio and male sex, the combination increasing the risk by 88%.

Conclusions

Our results suggest differential susceptibility to inflammation mediated by IL6 trans-signalling and subsequent CVE in men and women. The B/T ratio could be considered as a novel biomarker for cardiovascular risk in men, but not in women.

Function and proteolytic generation of the soluble interleukin-6 receptor in health and disease

The pleiotropic cytokine interleukin-6 (IL-6) is involved in numerous physiological and pathophysiological functions that include development, immune cell differentiation, inflammation and cancer. IL-6 can signal via the membrane-bound IL-6 receptor (IL-6R, classic signaling) or via soluble forms of the IL-6R (sIL-6R, trans-signaling). Both modes of signaling induce the formation of a homodimer of the signal transducing β-receptor glycoprotein 130 (gp130) and the activation of several intracellular signaling cascades, e.g. the Jak/STAT pathway. Intriguingly, only IL-6 trans-signaling is required for the pro-inflammatory properties of IL-6, while regenerative and anti-inflammatory functions are mediated via classic signaling. The sIL-6R is generated by different molecular mechanisms, including alternative mRNA splicing, proteolysis of the membrane-bound IL-6R and the release of extracellular vesicles. In this review, we give an in-depth overview on these molecular mechanisms with a special emphasize on IL-6R cleavage by the metalloprotease ADAM17 and other proteases. We discuss the biological functions of the sIL-6R and highlight attempts to selectively block IL-6 trans-signaling in pre-clinical animal models as well as in clinical studies in patients with inflammatory bowel disease.

Targeting cytokines and immune checkpoints in atherosclerosis with monoclonal antibodies

Over the past fifteen years, treatments using monoclonal antibodies specifically targeting cytokines have been developed to treat chronic inflammatory diseases, including rheumatoid arthritis or psoriasis, both associated with increased cardiovascular risk. The cardiovascular impact of these therapies allows us to validate the clinical relevance of the knowledge acquired from experimental studies about the role of cytokines in atherosclerosis. Several clinical studies have confirmed the protective effects of anti-TNFα and anti-IL-6R monoclonal antibodies against athero-thrombotic cardiovascular risk in patients with chronic inflammatory diseases. Yet, caution is needed since anti-TNFα treatment can aggravate chronic heart failure. More recently, the CANTOS study showed for the first time that an anti-inflammatory treatment using anti-IL-1β monoclonal antibody in coronary artery disease patients significantly reduced cardiovascular events. The effects of IL-23/IL-17 axis blockade on cardiovascular risk in patients with psoriasis or arthritis remain controversial. Several monoclonal antibodies targeting costimulatory molecules have also been developed, a direct way to confirm their involvement in atherothrombotic cardiovascular diseases. Blocking the CD28^-CD80/86 axis with Abatacept has been shown to reduce cardiovascular risk. In contrast, the treatment of cancer patients with antibodies blocking immune checkpoint inhibitory receptors, such as CTLA-4, PD1, or PDL1, could worsen the risk of atherothrombotic events. In the future, cardiologists will be increasingly solicited to assess the cardiovascular risk of patients suffering from chronic inflammatory diseases or cancer and participate in choosing the most appropriate treatment. At the same time, immunomodulatory approaches directly targeting cardiovascular diseases will be developed as a complement to the usual treatment strategies.

Tocilizumab Reduces Vasospasms, Neuronal Cell Death, and Microclot Formation in a Rabbit Model of Subarachnoid Hemorrhage

Early brain injury (EBI), delayed cerebral vasospasm (DCVS), and delayed cerebral ischemia (DCI) are common complications of subarachnoid hemorrhage (SAH). Inflammatory processes in the cerebrospinal fluid (CSF) are one of the causes for such complications. Our aim to study the effects of an IL-6 receptor antagonist (Tocilizumab) examines the occurrence of DCVS, neuronal cell death, and microclot formation in an acute SAH rabbit model. Twenty-nine New Zealand white rabbits were randomized into one of three groups as the SAH, SAH + Tocilizumab, and sham groups. In SAH groups, hemorrhage was induced by extracranial-intracranial arterial blood shunting from the subclavian artery into the cisterna magna under intracranial pressure (ICP) monitoring. In the second group, Tocilizumab was given once intravenously 1 h after SAH induction. Digital subtraction angiography was performed, and CSF and blood were sampled before and after (day 3) SAH induction. IL-6 plasma and CSF levels were measured. TUNEL, FJB, NeuN, and caspase-3 immunostaining were used to assess cell apoptosis, neurodegeneration, and neuronal cell death, respectively. Microclot formation was detected by fibrinogen immunostaining. Between baseline and follow-up, there was a significant reduction of angiographic DCVS (p < 0.0001) in the Tocilizumab compared with the SAH group. Tocilizumab treatment resulted in decreased neuronal cell death in the hippocampus (p = 0.006), basal cortex (p = 0.001), and decreased microclot formation (p = 0.02). Tocilizumab reduced DCVS, neuronal cell death, and microclot formation in a rabbit SAH model, and could be a potential treatment to prevent DCVS and DCI in SAH patients.

Associations of immunological proteins/traits with schizophrenia, major depression and bipolar disorder: A bi-directional two-sample mendelian randomization study

BACKGROUND

Schizophrenia, bipolar disorder and depression are associated with inflammation. However, it is unclear whether associations of immunological proteins/traits with these disorders are likely to be causal, or could be explained by reverse causality/residual confounding.

METHODS

We used bi-directional two-sample Mendelian randomization (MR) and multi-variable MR (MVMR) analysis to examine evidence of causality, specificity and direction of association of 20 immunological proteins/traits (pro-inflammatory cytokines: interleukin (IL)-6, tumour necrosis factor (TNF)-α, IL-12, IL-16, IL-17, IL-18; anti-inflammatory cytokines: IL-1 receptor antagonist (RA), IL-10, IL-13; chemokines: IL-8, monocyte chemo-attractant protein-1 (MCP-1); lymphoid growth-factors: soluble (s) IL-2Rα, IL-4, IL-7, IL-9; myeloid growth-factor: IL-5; acute phase protein: C-Reactive Protein (CRP); immune cells: neutrophils, lymphocytes; neurotrophic factor: brain derived neurotrophic factor (BDNF)) with schizophrenia, major depression and bipolar disorder.

RESULTS

Genetically-predicted IL-6 was associated with increased risk of schizophrenia in univariable MR (OR = 1.24; 95% C.I., 1.05-1.47) and with major depression in MVMR (OR = 1.08; 95% C.I., 1.03-1.12). These results survived Bonferroni-correction. Genetically-predicted sIL-2Rα (OR = 1.07; 95% C.I., 1.01-1.12) and IL-9 (OR = 1.06; 95% C.I., 1.01-1.11) were associated with increased schizophrenia risk. Genetically-predicted BDNF (OR = 0.97; 95% C.I., 0.94-1.00) and MCP-1 (OR = 0.96; 95% C.I., 0.91-0.99) were associated with reduced schizophrenia risk. However, these findings did not survive correction for multiple testing. The CRP-schizophrenia association attenuated completely after taking into account IL-6 and sIL-2Rα in MVMR (OR = 1.02; 95% C.I., 0.81-1.28). No significant associations were observed for bipolar disorder. Evidence from bidirectional MR did not support reverse causality.

CONCLUSIONS

We report evidence in support of potential causal associations of several immunological proteins/traits with schizophrenia, and of IL-6 with depression. Some of the findings did not survive correction for multiple testing and so replication in larger samples is required. Experimental studies are also required to further examine causality, mechanisms, and treatment potential for these immunological proteins/pathways for schizophrenia and depression.

Mendelian randomisation and experimental medicine approaches to IL-6 as a drug target in PAH

Background

Inflammation and dysregulated immunity are important in the development of pulmonary arterial hypertension (PAH). Compelling preclinical data supports the therapeutic blockade of interleukin-6 (IL-6) signalling.

Methods

We conducted a phase 2 open-label study of intravenous tocilizumab (8 mg·kg⁻¹) over 6 months in patients with group 1 PAH. Co-primary end-points were safety, defined by incidence and severity of adverse events, and change in pulmonary vascular resistance. Separately, a mendelian randomisation study was undertaken on 11 744 individuals with European ancestry including 2085 patients with idiopathic/heritable disease for the IL-6 receptor (IL6R) variant (rs7529229), known to associate with circulating IL-6R levels.

Results

We recruited 29 patients (male/female 10/19; mean±sd age 54.9±11.4 years). Of these, 19 had heritable/idiopathic PAH and 10 had connective tissue disease-associated PAH. Six were withdrawn prior to drug administration; 23 patients received at least one dose of tocilizumab. Tocilizumab was discontinued in four patients owing to serious adverse events. There were no deaths. Despite evidence of target engagement in plasma IL-6 and C-reactive protein levels, both intention-to-treat and modified intention-to-treat analyses demonstrated no change in pulmonary vascular resistance. Inflammatory markers did not predict treatment response. Mendelian randomisation did not support an effect of the lead IL6R variant on risk of PAH (OR 0.99, p=0.88).

Conclusion

Adverse events were consistent with the known safety profile of tocilizumab. Tocilizumab did not show any consistent treatment effect.

Tocilizumab did not block IL-6 signalling in pulmonary arterial hypertension. Multicentre mendelian randomisation studies additionally did not demonstrate evidence for IL-6R in pulmonary arterial hypertension.https://bit.ly/3xkDxS5

Management of inflammation in cardiovascular diseases

Cardiovascular disease is the leading cause of morbidity and mortality world-wide. Recently, the role of inflammation in the progression of diseases has significantly attracted considerable attention. In addition, various comorbidities, including diabetes, obesity, etc. exacerbate inflammation in the cardiovascular system, which ultimately leads to heart failure. Furthermore, cytokines released from specialized immune cells are key mediators of cardiac inflammation. Here, in this review article, we focused on the role of selected immune cells and cytokines (both pro-inflammatory and anti-inflammatory) in the regulation of cardiac inflammation and ultimately in cardiovascular diseases. While IL-1β, IL-6, TNFα, and IFNγ are associated with cardiac inflammation; IL-10, TGFβ, etc. are associated with resolution of inflammation and cardiac repair. IL-10 reduces cardiovascular inflammation and protects the cardiovascular system via interaction with SMAD2, p53, HuR, miR-375 and miR-21 pathway. In addition, we also highlighted recent advancements in the management of cardiac inflammation, including clinical trials of anti-inflammatory molecules to alleviate cardiovascular diseases.

Causal risk and protective factors in rheumatoid arthritis: A genetic update

The characterization of risk and protective factors in complex diseases such as rheumatoid arthritis (RA) has evolved from epidemiological studies, which test association, to the use of Mendelian randomization approaches, which test direct relationships. Indeed, direct associations with the mucosal origin of RA are retrieved with periodontal disease (Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans predominantly), interstitial lung involvement, tobacco smoking and air pollutants. Next, factors directly associated with an acquired immune response include genetic factors (HLA DRB1, PTPN22), capacity to produce anti-modified protein antibodies (AMPA), and relatives with a history of autoimmune diseases. Finally, factors can be also classified according to their direct capacity to interfere with the IL-6/CRP/sIL-IL6R proinflammatory pathway as risk factor (body fat, cardiometabolic factors, type 2 diabetes, depressive syndrome) or either as protective factors by controlling of sIL-6R levels (higher education level, and intelligence). Although some co-founders have been characterized (e.g. vitamin D, physical activity, cancer) the direct association with sex-discrepancy, pregnancy, and infections among other factors remains to be better explored.

Colchicine reduces extracellular vesicle NLRP3 inflammasome protein levels in chronic coronary disease: A LoDoCo2 biomarker substudy

BACKGROUND AND AIMS

Colchicine reduces the risk of cardiovascular events in patients with coronary disease. Colchicine has broad anti-inflammatory effects and part of the atheroprotective effects have been suggested to be the result of NLRP3 inflammasome inhibition. We studied the effect of colchicine on extracellular vesicle (EV) NLRP3 protein levels and inflammatory markers, high sensitivity-CRP (hs-CRP) and interleukin (IL)-6, in patients with chronic coronary disease.

METHODS

In vitro, the NLRP3 inflammasome was stimulated in PMA-differentiated- and undifferentiated THP-1 cells. In vivo, measurements were performed in serum obtained from 278 participants of the LoDoCo2 trial, one year after randomization to colchicine 0.5 mg once daily or placebo. EVs were isolated using precipitation. NLRP3 protein presence in EVs was confirmed using iodixanol density gradient centrifugation. Levels of NLRP3 protein, hs-CRP and IL-6 were measured using ELISA.

RESULTS

In vitro, NLRP3 inflammasome stimulation showed an increase of EV NLRP3 protein levels. EV NLRP3 protein levels were lower in patients treated with colchicine (median 1.38 ng/mL), compared to placebo (median 1.58 ng/mL) (p = 0.025). No difference was observed in serum NLRP3 protein levels. Serum hs-CRP levels were lower in patients treated with colchicine (median 0.80 mg/L) compared to placebo (median 1.34 mg/L) (p < 0.005). IL-6 levels were lower in patients treated with colchicine (median 2.07 ng/L) compared to placebo (median 2.59 ng/L), although this was not statistically significant (p = 0.076).

CONCLUSIONS

Colchicine leads to a reduction of EV NLRP3 protein levels. This indicates that inhibitory effects on the NLRP3 inflammasome might contribute to the atheroprotective effects of colchicine in coronary disease.

Inflammatory Molecular Mediators and Pathways Involved in Vascular Aging and Stroke: A Comprehensive Review

There is an increase in the incidence of cardiovascular diseases with aging and it is one of the leading causes of death worldwide. The main cardiovascular pathologies include atherosclerosis, stroke, myocardial infarction, hypertension and stroke. Chronic inflammation is one of the significant contributors to the age-related vascular diseases. Therefore, it is important to understand the molecular mechanisms of the persistent inflammatory conditions occurring in the blood vessels as well as the signaling pathways involved. Herein, we performed an extant search of literature involving PubMed, ISI, WoS and Scopus databases for retrieving all relevant articles with the most recent findings illustrating the potential role of various inflammatory mediators along with their proposed activated pathways in the pathogenesis and progression of vascular aging. We also highlight the major pathways contributing to age-related vascular disorders. The outlined molecular mechanisms, pathways and mediators of vascular aging represent potential drug targets that can be utilized to inhibit and/or slow the pathogenesis and progression of vascular aging.

Impact of a Vancomycin-Induced Shift of the Gut Microbiome in a Gram-Negative Direction on Plasma Factor VIII:C Levels: Results from a Randomized Controlled Trial

RATIONALE

 Inflammation is present in several conditions associated with risk of venous thromboembolism. The gut microbiome might be a source of systemic inflammation and activation of coagulation, by translocation of lipopolysaccharides from gram-negative bacteria to the systemic circulation.

OBJECTIVE

 To investigate whether a vancomycin-induced shift of the gut microbiome in a gram-negative direction influences systemic inflammation and plasma factor (F) VIII procoagulant activity (FVIII:C).

METHODS AND RESULTS

 We performed a randomized controlled trial including 43 healthy volunteers aged 19 to 37 years. Twenty-one were randomized to 7 days of oral vancomycin intake and 22 served as controls. Feces and blood were sampled at baseline, the day after the end of intervention, and 3 weeks after intervention. Gut microbiome composition was assessed by amplicon sequencing.

FVIII

C was measured using an activated partial thromboplastin time-based assay, cytokines were measured using multiplex technology, complement activation was measured using the enzyme-linked immunosorbent assay, and high-sensitivity C-reactive protein (CRP) was measured by an immunoturbidimetric assay. Vancomycin intake reduced gut microbiome diversity and increased the abundance of gram-negative bacteria. Change in FVIII:C in the intervention group was +4 IU/dL versus -6 IU/dL (p = 0.01) in the control group. A similar change was observed for log-transformed CRP (+0.21 mg/dL vs. -0.25 mg/dL, p = 0.04). The cytokines and complement activation markers remained similar in the two groups.

CONCLUSION

 The found slight increases in FVIII:C and CRP levels might support the hypothesis that a vancomycin-induced gram-negative shift in the gut microbiome could induce increased systemic inflammation and thereby a procoagulant state.

Unravelling the broader complexity of IL-6 involvement in health and disease

The classification of interleukin-6 (IL-6) as a pro-inflammatory cytokine undervalues the biological impact of this cytokine in health and disease. With broad activities affecting the immune system, tissue homeostasis and metabolic processes, IL-6 displays complex biology. The significance of these involvements has become increasingly important in clinical settings where IL-6 is identified as a prominent target for therapy. Here, clinical experience with IL-6 antagonists emphasises the need to understand the context-dependent properties of IL-6 within an inflammatory environment and the anticipated or unexpected consequences of IL-6 blockade. In this review, we will describe the immunobiology of IL-6 and explore the gamut of IL-6 bioactivity affecting the clinical response to biological drugs targeting this cytokine pathway.

Targeting residual inflammatory risk in coronary disease: to catch a monkey by its tail

Patients with coronary disease remain at high risk for future cardiovascular events, even with optimal risk factor modification, lipid-lowering drugs and antithrombotic regimens. A myriad of inflammatory pathways contribute to progression of the atherosclerotic burden in these patients. Only in the last few years has the inflammatory biology of atherosclerosis translated into clinical therapeutic options. Low-dose colchicine can provide a clinically relevant reduction in the risk for composite and individual major cardiovascular outcomes in patients with acute and chronic coronary syndromes. Among others, its anti-inflammatory effects in atherosclerosis seem to be related to neutrophil recruitment and adhesion, inflammasome inhibition, and morphological changes in platelets and platelet aggregation. Future research is aimed at further elucidating its particular mechanism of action, as well as identifying patients with the highest expected benefit and evaluating efficacy in other vascular beds. These data will help to formulate the role of colchicine and other anti-inflammatory drugs in patients with coronary disease and atherosclerosis in general in the near future.

Mendelian Randomization Studies in Stroke: Exploration of Risk Factors and Drug Targets With Human Genetic Data

Elucidating the causes of stroke is key to developing effective preventive strategies. The Mendelian randomization approach leverages genetic variants related to an exposure of interest to investigate the effects of varying that exposure on disease risk. The random allocation of genetic variants at conception reduces confounding from environmental factors and thus strengthens causal inference, analogous to treatment allocation in a randomized controlled trial. With the recent explosion in the availability of human genetic data, Mendelian randomization has proven a valuable tool for studying risk factors for stroke. In this review, we provide an overview of recent developments in the application of Mendelian randomization to unravel the pathophysiology of stroke subtypes and identify therapeutic targets for clinical translation. The approach has offered novel insight into the differential effects of risk factors and antihypertensive, lipid-lowering, and anticoagulant drug classes on risk of stroke subtypes. Analyses have further facilitated the prioritization of novel drug targets, such as for inflammatory pathways underlying large artery atherosclerotic stroke and for the coagulation cascade that contributes to cardioembolic stroke. With continued methodological advances coupled with the rapidly increasing availability of genetic data related to a broad range of stroke phenotypes, the potential for Mendelian randomization in this context is expanding exponentially.

Donor genetic variants in interleukin-6 and interleukin-6 receptor associate with biopsy-proven rejection following kidney transplantation

Rejection after kidney transplantation remains an important cause of allograft failure that markedly impacts morbidity. Cytokines are a major player in rejection, and we, therefore, explored the impact of interleukin-6 (IL6) and IL-6 receptor (IL6R) gene polymorphisms on the occurrence of rejection after renal transplantation. We performed an observational cohort study analyzing both donor and recipient DNA in 1271 renal transplant‐pairs from the University Medical Center Groningen in The Netherlands and associated single nucleotide polymorphisms (SNPs) with biopsy-proven rejection after kidney transplantation. The C-allele of the IL6R SNP (Asp358Ala; rs2228145 A > C, formerly rs8192284) in donor kidneys conferred a reduced risk of rejection following renal transplantation (HR 0.78 per C-allele; 95%-CI 0.67–0.90; P = 0.001). On the other hand, the C-allele of the IL6 SNP (at position-174 in the promoter; rs1800795 G > C) in donor kidneys was associated with an increased risk of rejection for male organ donors (HR per C-allele 1.31; 95%-CI 1.08–1.58; P = 0.0006), but not female organ donors (P = 0.33). In contrast, neither the IL6 nor IL6R SNP in the recipient showed an association with renal transplant rejection. In conclusion, donor IL6 and IL6R genotypes but not recipient genotypes represent an independent prognostic marker for biopsy-proven renal allograft rejection.

Role of inflammation in depression and anxiety: Tests for disorder specificity, linearity and potential causality of association in the UK Biobank

BACKGROUND

Concentrations of C-reactive protein (CRP), interleukin 6 (IL-6) and other inflammatory markers are elevated in people with depression and anxiety compared to controls, but evidence for disorder-specificity, linearity and potential causality is sparse.

METHODS

Using population-based data from up to 144,890 UK Biobank cohort participants, we tested associations of circulating CRP concentrations with depression and anxiety symptom scores and probable diagnosis, including tests for linearity, disorder-specificity and sex difference. We examined potential causality using 1-sample and 2-sample Mendelian randomisation (MR) analyses testing associations of genetically-predicted CRP concentration and IL-6 activity with depression and anxiety. The study was conducted from June 2019 to February 2021.

FINDINGS

CRP concentration was associated with depressive and anxiety symptom scores and with probable diagnoses of depression and generalised anxiety disorder (GAD) in a dose-response fashion. These associations were stronger for depression than for anxiety, and for women than for men although less consistently. MR analyses provided consistent results suggesting that genetically predicted higher IL-6 activity was associated with increased risk for depressive symptoms, while genetically-predicted higher CRP concentration was associated with decreased risks of depressive and anxiety symptoms.

INTERPRETATION

Altered activity of the IL-6/IL-6R pathway could be a risk factor for depression. The field now requires experimental studies of IL-6 modulation in humans and animal models to further examine causality, mechanisms and treatment potential. Such studies are also needed to elucidate mechanisms for divergent associations of genetically-predicted higher IL-6 activity (risk increasing) and higher CRP concentrations (protective) with depression/anxiety.

FUNDING

This research was funded in whole, or in part, by the Wellcome Trust (grant code: 201486/Z/16/Z). For the purpose of open access, the author has applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission. This work was supported by a Data Science Award from the MQ: Transforming Mental Health (grant code: MQDS17/40) to GMK and PBJ, which also supported ZY. GMK also acknowledges funding support from the Wellcome Trust (grant code: 201486/Z/16/Z), the Medical Research Council UK (grant code: MC_PC_17213 and MR/S037675/1), and the BMA Foundation (J Moulton grant 2019). NK and SM are supported by the International Max Planck Research School of Translational Psychiatry (IMPRS-TP). GDS works in the Medical Research Council Integrative Epidemiology Unit at the University of Bristol, which is supported by the Medical Research Council (MC_UU_00011/1).

Recognized and Potentially New Biomarkers-Their Role in Diagnosis and Prognosis of Cardiovascular Disease

Atherosclerosis and its consequences are the leading cause of mortality in the world. For this reason, we have reviewed atherosclerosis biomarkers and selected the most promising ones for review. We focused mainly on biomarkers related to inflammation and oxidative stress, such as the highly sensitive C-reactive protein (hs-CRP), interleukin 6 (IL-6), and lipoprotein-associated phospholipase A2 (Lp-PLA2). The microRNA (miRNA) and the usefulness of the bone mineralization, glucose, and lipid metabolism marker osteocalcin (OC) were also reviewed. The last biomarker we considered was angiogenin (ANG). Our review shows that due to the multifactorial nature of atherosclerosis, no single marker is known so far, the determination of which would unambiguously assess the severity of atherosclerosis and help without any doubt in the prognosis of cardiovascular risk.

The Role of C-reactive Protein in Patient Risk Stratification and Treatment

Atherosclerosis is a chronic inflammatory disease. Several circulating inflammatory markers have been proposed for clinical use due to their ability to predict future cardiovascular events and may be useful for identifying people at high risk who might benefit from specific treatment to reduce this risk. Moreover, the identification of new therapeutic targets will allow the development of drugs that can help reduce the high residual risk of recurrence of cardiovascular events in patients with coronary artery disease. The clinical benefits of reducing recurrent major cardiovascular events recently shown by canakinumab and colchicine have renewed the cardiology community’s interest in inflammation as an aetiopathogenic mechanism for atherosclerosis. This review explores the use of C-reactive protein, which is the most frequently studied biomarker in this context; the concept of residual risk in primary and secondary cardiovascular prevention; and the current recommendations in international guidelines regarding the role of this inflammatory biomarker in cardiovascular risk stratification.

Depression and interleukin-6 signaling: A Mendelian Randomization study

BACKGROUND

A large body of research has reported associations between depression and elevated interleukin-6 (IL-6), a cytokine with several roles including pro-inflammatory signaling. The nature and directionality of this relationship are not yet clear. In this study we use Mendelian Randomization to examine the possibility of a causal relationship between IL-6 and depressive symptoms, and to explore multiple signaling pathways that could serve as mechanisms for this relationship.

METHODS

This study uses a two-sample Mendelian Randomization design. Data come from the UK Biobank (n = 89,119) and published summary statistics from six existing GWAS analyses. The primary analysis focuses on the soluble interleukin-6 receptor (sIL-6R), which is involved in multiple signaling pathways. Exploratory analyses use C-reactive protein (CRP) and soluble glycoprotein 130 (sgp130) to further examine potential underlying mechanisms.

RESULTS

Results are consistent with a causal effect of sIL-6R on depression (PCA-IVW Odds Ratio: 1.023 (95% Confidence Interval: 1.006-1.039), p = 0.006). Exploratory analyses demonstrate that the relationship could be consistent with either decreased classical signaling or increased trans signaling as the underlying mechanism.

DISCUSSION

These results strengthen the body evidence implicating IL-6 signaling in depression. When compared with existing observational and animal findings, the direction of these results suggests involvement of IL-6 trans signaling. Further study is needed to examine whether IL6R genetic variants might influence IL-6 trans signaling in the brain, as well as to explore other potential pathways linking depression and inflammation.

Interplay between interleukin-6 signaling and the vascular endothelium in cytokine storms

Interleukin-6 (IL-6) plays a crucial role in host defense against infection and tissue injuries and is a bioindicator of multiple distinct types of cytokine storms. In this review, we present the current understanding of the diverse roles of IL-6, its receptors, and its signaling during acute severe systemic inflammation. IL-6 directly affects vascular endothelial cells, which produce several types of cytokines and chemokines and activate the coagulation cascade. Endothelial cell dysregulation, characterized by abnormal coagulation and vascular leakage, is a common complication in cytokine storms. Emerging evidence indicates that a humanized anti-IL-6 receptor antibody, tocilizumab, can effectively block IL-6 signaling and has beneficial effects in rheumatoid arthritis, juvenile systemic idiopathic arthritis, and Castleman's disease. Recent work has also demonstrated the beneficial effect of tocilizumab in chimeric antigen receptor T-cell therapy-induced cytokine storms as well as coronavirus disease 2019 (COVID-19). Here, we highlight the distinct contributions of IL-6 signaling to the pathogenesis of several types of cytokine storms and discuss potential therapeutic strategies for the management of cytokine storms, including those associated with sepsis and COVID-19.

Inflammation and Stroke Risk: A New Target for Prevention

New therapeutic approaches are required for secondary prevention of residual vascular risk after stroke. Diverse sources of evidence support a causal role for inflammation in the pathogenesis of stroke. Randomized controlled trials of anti-inflammatory agents have reported benefit for secondary prevention in patients with coronary disease. We review the data from observational studies supporting a role for inflammation in pathogenesis of stroke, overview randomized controlled trials of anti-inflammatory therapy in cardiac disease and discuss the potential implications for stroke prevention therapy.

Vascular consequences of inflammation: a position statement from the ESH Working Group on Vascular Structure and Function and the ARTERY Society

: Inflammation is a physiological response to aggression of pathogenic agents aimed at eliminating the aggressor agent and promoting healing. Excessive inflammation, however, may contribute to tissue damage and an alteration of arterial structure and function. Increased arterial stiffness is a well recognized cardiovascular risk factor independent of blood pressure levels and an intermediate endpoint for cardiovascular events. In the present review, we discuss immune-mediated mechanisms by which inflammation can influence arterial physiology and lead to vascular dysfunction such as atherosclerosis and arterial stiffening. We also show that acute inflammation predisposes the vasculature to arterial dysfunction and stiffening, and alteration of endothelial function and that chronic inflammatory diseases such as rheumatoid arthritis, inflammatory bowel disease and psoriasis are accompanied by profound arterial dysfunction which is proportional to the severity of inflammation. Current findings suggest that treatment of inflammation by targeted drugs leads to regression of arterial dysfunction. There is hope that these treatments will improve outcomes for patients.

Correlation Between Anosmia and Severity Along with Requirement of Tocilizumab in COVID-19 Patients

Anosmia with or without dysgeusia is frequently associated with Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) SARS-CoV-2 infection. SARS-CoV-2 virus affects the olfactory system and thus represents neurotropic and neuro-invasive nature of the virus. We found that tocilizumab’s role in reducing mortality in severe covid-19 infection is still questionable and aim of our study was correlation of anosmia and severity of covid-19 infection and requirement of tocilizumab in anosmia patients. To establish relationship between anosmia and severity of COVID-19 infection along with requirement of tocilizumab. This was a retrospective cum prospective cross sectional study done on COVID-19 patients who were admitted in normal COVID-19 ward and intensive care unit of Employee’s State Insurance Corporation Hospital, Udaipur and Maharaja Bhupal Hospital of Ravindra Nath Medical College between September 2020 and 15 January 2021 age group of 18 to 92 years, both sexes. We had asked about anosmia in all COVID-19 positive patients and followed all patients in perspective of severity of disease and tocilizumab. p value < 0.001 of prevalence of anosmia in COVID -19 patients who were isolated at home, admitted in ward and intensive care unit showed that anosmia is inversely related to severity of disease. Tocilizumab has no significant role in decreasing mortality in severe form of disease. Our study indicates that anosmia is related to the mildness of disease and there is no role of tocilizumab in decreasing the mortality in severe form of disease.

Association of Diet Quality With Prevalence of Clonal Hematopoiesis and Adverse Cardiovascular Events

Importance

Clonal hematopoiesis of indeterminate potential (CHIP), the expansion of somatic leukemogenic variations in hematopoietic stem cells, has been associated with atherosclerotic cardiovascular disease. Because the inherited risk of developing CHIP is low, lifestyle elements such as dietary factors may be associated with the development and outcomes of CHIP.

Objective

To examine whether there is an association between diet quality and the prevalence of CHIP.

Design, Setting, and Participants

This retrospective cohort study used data from participants in the UK Biobank, an ongoing population-based study in the United Kingdom that examines whole-exome sequencing data and survey-based information on health-associated behaviors. Individuals from the UK Biobank were recruited between 2006 and 2010 and followed up prospectively with linkage to health data records through May 2020. The present study included 44 111 participants in the UK Biobank who were age 40 to 70 years, had data available from whole-exome sequencing of blood DNA, and were free of coronary artery disease (CAD) or hematologic cancer at baseline.

Exposures

Diet quality was categorized as unhealthy if the intake of healthy elements (fruits and vegetables) was lower than the median of all survey responses, and the intake of unhealthy elements (red meat, processed food, and added salt) was higher than the median. Diets were classified as healthy if the intake of healthy elements was higher than the median, and the intake of unhealthy elements was lower than the median. The presence of CHIP was detected by data from whole-exome sequencing of blood DNA.

Main Outcomes and Measures

The primary outcome was CHIP prevalence. Multivariable logistic regression analysis was used to examine the association between diet quality and the presence of CHIP. Multivariable Cox proportional hazards models were used to assess the association of incident events (acute coronary syndromes, coronary revascularization, or death) in each diet quality category stratified by the presence of CHIP.

Results

Among 44 111 participants (mean [SD] age at time of blood sample collection, 56.3 [8.0] years; 24 507 women [55.6%]), 2271 individuals (5.1%) had an unhealthy diet, 38 552 individuals (87.4%) had an intermediate diet, and 3288 individuals (7.5%) had a healthy diet. A total of 2507 individuals (5.7%) had CHIP, and the prevalence of CHIP decreased as diet quality improved from unhealthy (162 of 2271 participants [7.1%]) to intermediate (2177 of 38 552 participants [5.7%]) to healthy (168 of 3288 participants [5.1%]; P = .003 for trend). Compared with individuals without CHIP who had an intermediate diet, the rates of incident cardiovascular events progressively decreased among those with CHIP who had an unhealthy diet (hazard ratio [HR], 1.52; 95% CI, 1.04-2.22) and those with CHIP who had a healthy diet (HR, 0.99; 95% CI, 0.62-1.58) over a median of 10.0 years (interquartile range, 9.6-10.4 years) of follow-up.

Conclusions and Relevance

This cohort study suggests that an unhealthy diet quality may be associated with a higher prevalence of CHIP and higher rates of adverse cardiovascular events and death independent of CHIP status.

Association of Interleukin-6 Signaling and C-Reactive Protein With Intracranial Aneurysm: A Mendelian Randomization and Genetic Correlation Study

Background and objective

Evidence suggests that interleukin-6 (IL6) signaling is causally associated with aortic aneurysm independently of the effect of C-reactive protein (CRP). We aimed to explore the genetic overlap and associations between inflammation (IL6 signaling and CRP) and intracranial aneurysm (IA) risk.

Methods

Two-sample Mendelian randomization (MR) methods were used to assess the causal effects of soluble IL6 receptor (sIL6R) (n = 21,758) and CRP (n = 204,402) levels on IA (7,495 cases and 71,934 controls) risk using genome-wide association study summary data of European individuals. Cross-trait linkage disequilibrium score regression was used to estimate the genetic correlations of CRP (n = 400,094) with IA.

Results

MR analyses showed that circulating sIL6R and CRP levels were not associated with the risk of IA. The odds ratios based on the inverse variance-weighted method were 0.986 (0.950-1.023, p = 0.45) and 0.957 (0.846-1.084, p = 0.49) for sIL6R and CRP, respectively. MR analyses using data of ruptured and unruptured IA each showed no association. Linkage disequilibrium score regression showed that the genetic correlation between CRP and IA was 0.16 (SE = 0.04, p = 0.0003). The genetic correlation diminished after conditioning IA on blood pressure (0.07 ± 0.05, p = 0.16), smoking (0.02 ± 0.05, p = 0.65), or blood pressure plus smoking (-0.03 ± 0.05, p = 0.53).

Conclusion

Using associated genetic variants as instrument variables, two-sample MR analyses showed no evidence that circulating sIL6R and CRP levels were associated with IA risk. Although a positive genetic correlation was found between CRP levels and IA risk, it was mainly driven by the shared genetic background of blood pressure and smoking with both CRP and IA.

Association between ABO and Duffy blood types and circulating chemokines and cytokines

Blood group antigens are inherited traits that may play a role in immune and inflammatory processes. We investigated associations between blood groups and circulating inflammation-related molecules in 3537 non-Hispanic white participants selected from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Whole-genome scans were used to infer blood types for 12 common antigen systems based on well-characterized single-nucleotide polymorphisms. Serum levels of 96 biomarkers were measured on multiplex fluorescent bead-based panels. We estimated marker associations with blood type using weighted linear or logistic regression models adjusted for age, sex, smoking status, and principal components of population substructure. Bonferroni correction was used to control for multiple comparisons, with two-sided p values < 0.05 considered statistically significant. Among the 1152 associations tested, 10 were statistically significant. Duffy blood type was associated with levels of CXCL6/GCP2, CXCL5/ENA78, CCL11/EOTAXIN, CXCL1/GRO, CCL2/MCP1, CCL13/MCP4, and CCL17/TARC, whereas ABO blood type was associated with levels of sVEGFR2, sVEGFR3, and sGP130. Post hoc pairwise t-tests showed that individuals with type Fy(a+b−) had the lowest mean levels of all Duffy-associated markers, while individuals with type A blood had the lowest mean levels of all ABO-associated markers. Additional work is warranted to explore potential clinical implications of these differences.

Inflammatory Markers in Cardiovascular Disease; Lessons Learned and Future Perspectives

BACKGROUND

Cardiovascular disease (CVD) still remains the leading cause of morbidity and mortality worldwide. It is now established that inflammation plays a crucial role in atherosclerosis and atherothrombosis, and thus, it is closely linked to cardiovascular disease.

OBJECTIVE

The aim of the present review is to summarize and critically appraise the most relevant evidence regarding the potential use of inflammatory markers in the field of CVD.

METHODS

We conducted a comprehensive research of the relevant literature, searching MEDLINE from its inception until November 2018, primarily for meta-analyses, randomized controlled trials and observational studies.

RESULTS

Established markers of inflammation, mainly C-reactive protein, have yielded significant results both for primary and secondary prevention of CVD. Newer markers, such as lipoprotein-associated phospholipase A2, lectin-like oxidized low-density lipoprotein receptor-1, cytokines, myeloperoxidase, cell adhesion molecules, matrix metalloproteinases, and the CD40/CD40 ligand system, have been largely evaluated in human studies, enrolling both individuals from the general population and patients with established CVD. Some markers have yielded conflicting results; however, others are now recognized not only as promising biomarkers of CVD, but also as potential therapeutic targets, establishing the role of anti-inflammatory and pleiotropic drugs in CVD.

CONCLUSION

There is significant evidence regarding the role of consolidated and novel inflammatory markers in the field of diagnosis and prognosis of CVD. However, multimarker model assessment, validation of cut-off values and cost-effectiveness analyses are required in order for those markers to be integrated into daily clinical practice.

Integrating genomics with biomarkers and therapeutic targets to invigorate cardiovascular drug development

Drug development in cardiovascular disease is stagnating, with lack of efficacy and adverse effects being barriers to innovation. Human genetics can provide compelling evidence of causation through approaches such as Mendelian randomization, with genetic support for causation increasing the probability of a clinical trial succeeding. Mendelian randomization applied to quantitative traits can identify risk factors for disease that are both causal and amenable to therapeutic modification. However, important differences exist between genetic investigations of a biomarker (such as HDL cholesterol) and a drug target aimed at modifying the same biomarker of interest (such as cholesteryl ester transfer protein), with implications for the methodology, interpretation and application of Mendelian randomization to drug development. Differences include the comparative nature of the genetic architecture - that is, biomarkers are typically polygenic, whereas protein drug targets are influenced by either cis-acting or trans-acting genetic variants - and the potential for drug targets to show disease associations that might differ from those of the biomarker that they are intended to modify (target-mediated pleiotropy). In this Review, we compare and contrast the use of Mendelian randomization to evaluate potential drug targets versus quantitative traits. We explain how genetic epidemiological studies can be used to assess the aetiological roles of biomarkers in disease and to prioritize drug targets, including designing their evaluation in clinical trials.

The Role of Convalescent Plasma and Tocilizumab in the Management of COVID-19 Infection: A Cohort of 110 Patients from a Tertiary Care Hospital in Oman

AIM

As Coronavirus Disease-2019 (COVID-19) pandemic continues to evolve, the search for safe and effective therapeutic interventions remain essential.

METHODS

We conducted a retrospective cohort study on patients hospitalized with laboratory confirmed severe acute respiratory syndrome coronavirus-2 infection, comparing standard of care along with Convalescent Plasma with or without Tocilizumab (CP vs. CPT).

RESULTS

A total of 110 patients were enrolled with an overall mean age of 50 ± 16 years. Patients on CPT were more likely to have had acute respiratory distress syndrome (77% vs. 42%; p < 0.001), sepsis (9.7% vs. 0; p = 0.036), chest X-ray abnormalities (71% vs. 44%; p = 0.004), intensive care unit admission (84% vs. 56%; p = 0.001) as well as being on mechanical ventilation (79% vs. 48%; p = 0.001). After CPT treatment, all measured inflammatory markers, except interleukine-6, showed an overall steady decline over time (all p-values <0.05) and the ventilatory parameters showed significant improvement of PaO2/FiO2 ratio from 127 to 188 within 7 days (p < 0.001). Additionally, 52% (32/62) of the patients had favorable outcome, either as improvement of ventilatory parameters or extubation within 14 days of hospitalization. However, mortality rate in those on CPT was higher than those who received CP alone (24% vs. 8.3%; p = 0.041).

CONCLUSION

In patients with severe COVID-19 infection, using tocilizumab with convalescent plasma is associated with improvement in inflammatory and ventilatory parameters but no effect on mortality. These findings require validation from randomized clinical trials.

IL-6 inhibition with ziltivekimab in patients at high atherosclerotic risk (RESCUE): a double-blind, randomised, placebo-controlled, phase 2 trial

BACKGROUND

IL-6 has emerged as a pivotal factor in atherothrombosis. Yet, the safety and efficacy of IL-6 inhibition among individuals at high atherosclerotic risk but without a systemic inflammatory disorder is unknown. We therefore addressed whether ziltivekimab, a fully human monoclonal antibody directed against the IL-6 ligand, safely and effectively reduces biomarkers of inflammation and thrombosis among patients with high cardiovascular risk. We focused on individuals with elevated high-sensitivity CRP and chronic kidney disease, a group with substantial unmet clinical need in whom previous studies in inflammation inhibition have shown efficacy for cardiovascular event reduction.

METHODS

RESCUE is a randomised, double-blind, phase 2 trial done at 40 clinical sites in the USA. Inclusion criteria were age 18 years or older, moderate to severe chronic kidney disease, and high-sensitivity CRP of at least 2 mg/L. Participants were randomly allocated (1:1:1:1) to subcutaneous administration of placebo or ziltivekimab 7·5 mg, 15 mg, or 30 mg every 4 weeks up to 24 weeks. The primary outcome was percentage change from baseline in high-sensitivity CRP after 12 weeks of treatment with ziltivekimab compared with placebo, with additional biomarker and safety data collected over 24 weeks of treatment. Primary analyses were done in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of assigned treatment. The trial is registered with ClinicalTrials.gov, NCT03926117.

FINDINGS

Between June 17, 2019, and Jan 14, 2020, 264 participants were enrolled into the trial, of whom 66 were randomly assigned to each of the four treatment groups. At 12 weeks after randomisation, median high-sensitivity CRP levels were reduced by 77% for the 7·5 mg group, 88% for the 15 mg group, and 92% for the 30 mg group compared with 4% for the placebo group. As such, the median pairwise differences in percentage change in high-sensitivity CRP between the ziltivekimab and placebo groups, after aligning for strata, were -66·2% for the 7·5 mg group, -77·7% for the 15 mg group, and -87·8% for the 30 mg group (all p<0·0001). Effects were stable over the 24-week treatment period. Dose-dependent reductions were also observed for fibrinogen, serum amyloid A, haptoglobin, secretory phospholipase A2, and lipoprotein(a). Ziltivekimab was well tolerated, did not affect the total cholesterol to HDL cholesterol ratio, and there were no serious injection-site reactions, sustained grade 3 or 4 neutropenia or thrombocytopenia.

INTERPRETATION

Ziltivekimab markedly reduced biomarkers of inflammation and thrombosis relevant to atherosclerosis. On the basis of these data, a large-scale cardiovascular outcomes trial will investigate the effect of ziltivekimab in patients with chronic kidney disease, increased high-sensitivity CRP, and established cardiovascular disease.

FUNDING

Novo Nordisk.

Antibody-Based Therapeutics for Atherosclerosis and Cardiovascular Diseases

Cardiovascular disease is the leading cause of death worldwide, and its prevalence is increasing due to the aging of societies. Atherosclerosis, a type of chronic inflammatory disease that occurs in arteries, is considered to be the main cause of cardiovascular diseases such as ischemic heart disease or stroke. In addition, the inflammatory response caused by atherosclerosis confers a significant effect on chronic inflammatory diseases such as psoriasis and rheumatic arthritis. Here, we review the mechanism of action of the main causes of atherosclerosis such as plasma LDL level and inflammation; furthermore, we review the recent findings on the preclinical and clinical effects of antibodies that reduce the LDL level and those that neutralize the cytokines involved in inflammation. The apolipoprotein B autoantibody and anti-PCSK9 antibody reduced the level of LDL and plaques in animal studies, but failed to significantly reduce carotid inflammation plaques in clinical trials. The monoclonal antibodies against PCSK9 (alirocumab, evolocumab), which are used as a treatment for hyperlipidemia, lowered cholesterol levels and the incidence of cardiovascular diseases. Antibodies that neutralize inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-17, and IL-12/23) have shown promising but contradictory results and thus warrant further research.

Beyond Lipoprotein(a) plasma measurements: Lipoprotein(a) and inflammation

Genome wide association, epidemiological, and clinical studies have established high lipoprotein(a) [Lp(a)] as a causal risk factor for atherosclerotic cardiovascular disease (ASCVD). Lp(a) is an apoB100 containing lipoprotein covalently bound to apolipoprotein(a) [apo(a)], a glycoprotein. Plasma Lp(a) levels are to a large extent determined by genetics. Its link to cardiovascular disease (CVD) may be driven by its pro-inflammatory effects, of which its association with oxidized phospholipids (oxPL) bound to Lp(a) is the most studied. Various inflammatory conditions, such as rheumatoid arthritis (RA), systemic lupus erythematosus, acquired immunodeficiency syndrome, and chronic renal failure are associated with high Lp(a) levels. In cases of RA, high Lp(a) levels are reversed by interleukin-6 receptor (IL-6R) blockade by tocilizumab, suggesting a potential role for IL-6 in regulating Lp(a) plasma levels. Elevated levels of IL-6 and IL-6R polymorphisms are associated with CVD. Therapies aimed at lowering apo(a) and thereby reducing plasma Lp(a) levels are in clinical trials. Their results will determine if reductions in apo(a) and Lp(a) decrease cardiovascular outcomes. As we enter this new arena of available treatments, there is a need to improve our understanding of mechanisms. This review will focus on the role of Lp(a) in inflammation and CVD.

Interleukin-6 Signaling and Anti-Interleukin-6 Therapeutics in Cardiovascular Disease

IL (interleukin)-6 is a pivotal cytokine of innate immunity, which enacts a broad set of physiological functions traditionally associated with host defense, immune cell regulation, proliferation, and differentiation. Following recognition of innate immune pathways leading from the NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) inflammasome to IL-1 to IL-6 and on to the hepatically derived clinical biomarker CRP (C-reactive protein), an expanding literature has led to understanding of the proatherogenic role for IL-6 in cardiovascular disease and thus the potential for IL-6 inhibition as a novel method for vascular protection. In this review, we provide an overview of the mechanisms by which IL-6 signaling occurs and how that impacts upon pharmacological inhibition; describe murine models of IL-6 and atherogenesis; summarize human epidemiological data outlining the utility of IL-6 as a biomarker of vascular risk; outline genetic data suggesting a causal role for IL-6 in systemic atherothrombosis and aneurysm formation; and then detail the potential role of IL-6 inhibition in stable coronary disease, acute coronary syndromes, heart failure, and the atherothrombotic complications associated with chronic kidney disease and end-stage renal failure. Finally, we review anti-inflammatory and antithrombotic findings for ziltivekimab, a novel IL-6 ligand inhibitor being developed specifically for use in atherosclerotic disease and poised to be tested formally in a large-scale cardiovascular outcomes trial focused on individuals with chronic kidney disease and elevated levels of CRP, a population at high residual atherothrombotic risk, high residual inflammatory risk, and considerable unmet clinical need.

Comparison of interleukin-6, C-reactive protein, and low-density lipoprotein cholesterol as biomarkers of residual risk in contemporary practice: secondary analyses from the Cardiovascular Inflammation Reduction Trial

AIMS

In epidemiologic cohorts initiated >30 years ago, inflammatory biomarkers, such as interleukin-6 (IL-6) and high-sensitivity C-reactive protein (hsCRP) were shown to independently predict future cardiovascular events with a magnitude of effect comparable to that of low-density lipoprotein cholesterol (LDLC). Whether aggressive contemporary therapy for atherosclerosis has altered these relationships is unknown yet has major implications for future drug development.

METHODS AND RESULTS

Interleukin-6, hsCRP, and LDLC were measured at baseline in up to 4168 North American patients enrolled in the contemporary Cardiovascular Inflammation Reduction Trial with prior myocardial infarction or multivessel coronary disease who additionally had diabetes or metabolic syndrome and were followed for a period of up to 5 years for incident major recurrent cardiovascular events and all-cause mortality. Three-quarters of the cohort were previously revascularized and the great majority was taking statins, angiotensin blocking agents, beta-blockers, and antithrombotic agents. Participants were randomly allocated to low-dose methotrexate 15 mg weekly or to placebo. Randomized use of methotrexate had no effect on event rates nor plasma levels of IL-6, hsCRP, or LDL over time. Yet, baseline levels of IL-6, hsCRP, and LDLC were all predictors of major recurrent cardiovascular events; adjusted hazard ratios [HR; 95% confidence interval (CI)] for the lowest to highest baseline quartiles of IL-6 were 1.0 (referent), 1.66 (1.18-2.35), 1.92 (1.36-2.70), and 2.11 (1.49-2.99; P < 0.0001), while adjusted HRs for increasing quartiles of hsCRP were 1.0 (referent), 1.28 (0.92-1.79), 1.73 (1.25-2.38), and 1.79 (1.28-2.50; P < 0.0001) and adjusted HRs for increasing quartiles of LDLC were 1.0 (referent), 1.12 (0.78-1.62), 1.25 (0.87-1.79), and 2.38 (1.72-3.30; P < 0.0001). Effect estimates were not statistically different in these analyses for comparisons between IL-6, hsCRP, or LDLC, although IL-6 was the strongest predictor of all-cause mortality. The highest absolute risks were observed among those with elevated levels of both cholesterol and inflammation [HR 6.4 (95% CI 2.9-14.1) for those in the top quartiles of baseline IL-6 and LDLC, HR 4.9 (95% CI 2.6-9.4) for those in the top quartiles of baseline hsCRP and LDLC, both P < 0.0001].

CONCLUSION

Despite aggressive contemporary secondary prevention efforts, the relationships between inflammation, cholesterol, and cardiovascular risk are largely unchanged from those described two decades ago. These data are consistent with the hypothesis that future treatments for atherosclerosis may require a combination of inflammation inhibition and additional cholesterol reduction.

CLINICAL TRIAL

ClinicalTrials.gov NCT01594333.

Targeting cardiovascular inflammation: next steps in clinical translation

Systemic vascular inflammation plays multiple maladaptive roles which contribute to the progression and destabilization of atherosclerotic cardiovascular disease (ASCVD). These roles include: (i) driving atheroprogression in the clinically stable phase of disease; (ii) inciting atheroma destabilization and precipitating acute coronary syndromes (ACS); and (iii) responding to cardiomyocyte necrosis in myocardial infarction (MI). Despite an evolving understanding of these biologic processes, successful clinical translation into effective therapies has proven challenging. Realizing the promise of targeting inflammation in the prevention and treatment of ASCVD will likely require more individualized approaches, as the degree of inflammation differs among cardiovascular patients. A large body of evidence has accumulated supporting the use of high-sensitivity C-reactive protein (hsCRP) as a clinical measure of inflammation. Appreciating the mechanistic diversity of ACS triggers and the kinetics of hsCRP in MI may resolve purported inconsistencies from prior observational studies. Future clinical trial designs incorporating hsCRP may hold promise to enable individualized approaches. The aim of this Clinical Review is to summarize the current understanding of how inflammation contributes to ASCVD progression, destabilization, and adverse clinical outcomes. We offer forward-looking perspective on what next steps may enable successful clinical translation into effective therapeutic approaches-enabling targeting the right patients with the right therapy at the right time-on the road to more individualized ASCVD care.

Effect of Biologics on Cardiovascular Inflammation: Mechanistic Insights and Risk Reduction

It is increasingly recognized that atherosclerosis and consequently cardiovascular disease (CVD) are closely linked with inflammatory processes. The latter is in the center of the pathogenic mechanism underlying autoimmune rheumatic diseases (ARD). It follows then, that optimal control of inflammation in ARDs may lead to a decrease of the accompanied CVD risk. Major trials (eg, CANTOS, CIRT), aimed at examining the possible benefits of immunomodulatory treatments in CVD, demonstrated conflicting results. On the other hand, substantial evidence is accumulating about the possible beneficial effects of biologic disease modifying antirheumatic drugs (bDMARDs) in patients with ARDs, particularly those with rheumatoid arthritis (RA). It seems that bDMARDs (some more than others) alter the lipid profile in RA patients but do not adversely affect, in most cases, the TC/HDL ratio. Favorable effects are noted for arterial stiffness and endothelial function. This is reflected in the lower risk for CVD events, seen in observational studies of RA patients treated with bDMARDs. It should be stressed that more data exist for the TNF-inhibitors than for other bDMARDs, such as tocilizumab, abatacept and rituximab. As regards the spondyloarthropathies (SpA), data are less robust. For TNF-inhibitors, effects appear to be on par with those seen in RA but no conclusions can be drawn for newer biologic drugs used in SpA (eg, IL-17 blockers). Finally, there is accumulating evidence for a beneficial effect of immunosuppressive treatment in cardiac inflammation and function in several ARDs. Introduction of newer therapeutic options in clinical practice seem to have a positive impact on CVD in the setting of ARD. This is probably due to better control of inflammation, but direct improvement in vascular pathology is also a valid hypothesis. Most data are derived from observational studies and, therefore, randomized controlled trials are needed to assess the possible favorable effect of bDMARDs on CVD outcomes.

Inflamm-ageing: the role of inflammation in age-dependent cardiovascular disease

The ongoing worldwide increase in life expectancy portends a rising prevalence of age-related cardiovascular (CV) diseases in the coming decades that demands a deeper understanding of their molecular mechanisms. Inflammation has recently emerged as an important contributor for CV disease development. Indeed, a state of chronic sterile low-grade inflammation characterizes older organisms (also known as inflamm-ageing) and participates pivotally in the development of frailty, disability, and most chronic degenerative diseases including age-related CV and cerebrovascular afflictions. Due to chronic activation of inflammasomes and to reduced endogenous anti-inflammatory mechanisms, inflamm-ageing contributes to the activation of leucocytes, endothelial, and vascular smooth muscle cells, thus accelerating vascular ageing and atherosclerosis. Furthermore, inflamm-ageing promotes the development of catastrophic athero-thrombotic complications by enhancing platelet reactivity and predisposing to plaque rupture and erosion. Thus, inflamm-ageing and its contributors or molecular mediators might furnish targets for novel therapeutic strategies that could promote healthy ageing and conserve resources for health care systems worldwide. Here, we discuss recent findings in the pathophysiology of inflamm-ageing, the impact of these processes on the development of age-related CV diseases, results from clinical trials targeting its components and the potential implementation of these advances into daily clinical practice.

Residual inflammatory risk associated with interleukin-18 and interleukin-6 after successful interleukin-1β inhibition with canakinumab: further rationale for the development of targeted anti-cytokine therapies for the treatment of atherothrombosis

AIMS

The Canakinumab Antiinflammatory Thrombosis Outcomes Study (CANTOS) established that targeting inflammation with interleukin-1β (IL-1β) inhibition can significantly reduce cardiovascular (CV) event rates in the absence of any beneficial effects on cholesterol. Yet, CANTOS participants treated with both high-intensity statins and canakinumab remain at considerable risk for recurrent CV events. Both interleukin-18 (IL-18, which like IL-1β requires the NLRP3 inflammasome for activation) and interleukin-6 (IL-6, a pro-inflammatory cytokine downstream of IL-1) may contribute to the recurrent events that occur even on canakinumab therapy, and thus represent novel targets for treating atherothrombosis.

METHODS AND RESULTS

Plasma samples from 4848 stable post-myocardial infarction patients who were assigned to active IL-1β inhibition or placebo within CANTOS underwent measurement of IL-18 and IL-6 both before and after initiation of canakinumab using validated ELISA. All participants were followed over a median 3.7-year period (maximum 5 years) for recurrent major adverse cardiovascular events (MACE) and for all-cause mortality. Compared to placebo, canakinumab significantly reduced IL-6 levels in a dose-dependent manner yielding placebo-subtracted median percent reductions in IL-6 at 3 months of 24.8%, 36.3%, and 43.2% for the 50, 150, and 300 mg doses, respectively (all P-values <0.001). By contrast, no dose of canakinumab significantly altered IL-18 levels measured at 3 months (all effects <1%, all P-values > 0.05). Yet, despite these differential plasma effects, either baseline and on-treatment levels of IL-18 or IL-6 associated with rates of future CV events. For example, for MACE, each tertile increase in IL-18 measured 3 months after canakinumab initiation associated with a 15% increase in risk [95% confidence interval (CI) 3-29%, P = 0.016], while each tertile increase in IL-6 measured 3 months after canakinumab initiation associated with a 42% increase in risk (95% CI 26-59%, P < 0.0001). Similar effects were observed for MACE-plus, CV death, all-cause mortality, and the for the combination endpoint of all vascular events inclusive of revascularization procedures and hospitalization for congestive heart failure. In baseline as well as on-treatment analyses, risks were highest among those with the highest levels of both IL-18 and IL-6.

CONCLUSION

There remains substantial residual inflammatory risk related to both IL-18 and IL-6 after IL-1β inhibition with canakinumab These data support further pharmacologic development of therapies for atherothrombosis that target IL-18 or IL-6 signalling, or that can simultaneously inhibit both IL-1β and IL-18 (such as NLRP3 inflammasome inhibitors).

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT01327846.

Atherosclerotic Cardiovascular Disease in Rheumatoid Arthritis: Impact of Inflammation and Antirheumatic Treatment

Patients with rheumatoid arthritis (RA) are at approximately 1.5-fold risk of atherosclerotic cardiovascular disease (CVD) compared with the general population, a phenomenon resulting from combined effects of traditional CVD risk factors and systemic inflammation. Rheumatoid synovitis and unstable atherosclerotic plaques share common inflammatory mechanisms, such as expression of proinflammatory cytokines interleukin (IL)-1, tumour necrosis factor (TNF)-α and IL-6. RA patients are undertreated in terms of CVD prevention, and structured CVD prevention programmes are warranted. Alongside management of traditional risk factors, suppressing systemic inflammation with antirheumatic medication is fundamental for the reduction of CVD risk among this high-risk patient group. Many antirheumatic drugs, especially methotrexate, TNF-α-inhibitors and IL-6-inhibitors are associated with reduced risk of CVD in observational studies among RA patients, but randomised controlled trials with hard CVD endpoints are lacking. In patients without rheumatic disease, anti-inflammatory therapies targeting nucleotide-binding oligomerisation domain, leucine-rich repeat and pyrin domain-containing protein 3 inflammasome and the IL-1/IL-6 pathway arise as potential therapies after an atherosclerotic CVD event.

A feedback loop: Interactions between Inflammatory Signals and Clonal Hematopoiesis in Cardiovascular Disease

Age and inflammation are powerful drivers of cardiovascular disease. With the growing recognition that traditional cardiovascular risk factors are not fully accurate predictors of cardiovascular disease, recent studies have revealed the prevalence of positive selection of somatic cell mutations in hematopoietic stem cells in the elderly population, which can cause clonal hematopoiesis. Interestingly, clonal hematopoiesis is not only associated with cancer and death, but also closely related to the risk of increased cardiovascular disease due to mutations in TET2, DNMT3A, ASXL1, and JAK2. However, the mechanism of the interaction of clonal hematopoiesis and cardiovascular disease is only partially understood. In mice, somatic mutations have led to significantly increased expression of inflammatory genes in innate immune cells, which may explain the relationship between mutations and cardiovascular disease. Here, we further discuss the association between inflammatory signaling, clonal hematopoiesis, and cardiovascular disease,and using two hypotheses to propose a feedback loop between inflammatory signaling and clonal hematopoiesis for getting insight into the pathogenesis of cardiovascular diseases in depth. Therapies targeting mutant clones or increased inflammatory mediators may be useful for ameliorating the risk of cardiovascular disease.

Genetically determined NLRP3 inflammasome activation associates with systemic inflammation and cardiovascular mortality

AIMS

Inflammation plays an important role in cardiovascular disease (CVD) development. The NOD-like receptor protein-3 (NLRP3) inflammasome contributes to the development of atherosclerosis in animal models. Components of the NLRP3 inflammasome pathway such as interleukin-1β can therapeutically be targeted. Associations of genetically determined inflammasome-mediated systemic inflammation with CVD and mortality in humans are unknown.

METHODS AND RESULTS

We explored the association of genetic NLRP3 variants with prevalent CVD and cardiovascular mortality in 538 167 subjects on the individual participant level in an explorative gene-centric approach without performing multiple testing. Functional relevance of single-nucleotide polymorphisms on NLRP3 inflammasome activation has been evaluated in monocyte-enriched peripheral blood mononuclear cells (PBMCs). Genetic analyses identified the highly prevalent (minor allele frequency 39.9%) intronic NLRP3 variant rs10754555 to affect NLRP3 gene expression. rs10754555 carriers showed significantly higher C-reactive protein and serum amyloid A plasma levels. Carriers of the G allele showed higher NLRP3 inflammasome activation in isolated human PBMCs. In carriers of the rs10754555 variant, the prevalence of coronary artery disease was significantly higher as compared to non-carriers with a significant interaction between rs10754555 and age. Importantly, rs10754555 carriers had significantly higher risk for cardiovascular mortality during follow-up. Inflammasome inducers (e.g. urate, triglycerides, apolipoprotein C3) modulated the association between rs10754555 and mortality.

CONCLUSION

The NLRP3 intronic variant rs10754555 is associated with increased systemic inflammation, inflammasome activation, prevalent coronary artery disease, and mortality. This study provides evidence for a substantial role of genetically driven systemic inflammation in CVD and highlights the NLRP3 inflammasome as a therapeutic target.

Hydroxychloroquine reduces interleukin-6 levels after myocardial infarction: The randomized, double-blind, placebo-controlled OXI pilot trial

OBJECTIVES

To determine the anti-inflammatory effect and safety of hydroxychloroquine after acute myocardial infarction.

METHOD

In this multicenter, double-blind, placebo-controlled OXI trial, 125 myocardial infarction patients were randomized at a median of 43 h after hospitalization to receive hydroxychloroquine 300 mg (n = 64) or placebo (n = 61) once daily for 6 months and, followed for an average of 32 months. Laboratory values were measured at baseline, 1, 6, and 12 months.

RESULTS

The levels of interleukin-6 (IL-6) were comparable at baseline between study groups (p = 0.18). At six months, the IL-6 levels were lower in the hydroxychloroquine group (p = 0.042, between groups), and in the on-treatment analysis, the difference at this time point was even more pronounced (p = 0.019, respectively). The high-sensitivity C-reactive protein levels did not differ significantly between study groups at any time points. Eleven patients in the hydroxychloroquine group and four in the placebo group had adverse events leading to interruption or withdrawal of study medication, none of which was serious (p = 0.10, between groups).

CONCLUSIONS

In patients with myocardial infarction, hydroxychloroquine reduced IL-6 levels significantly more than did placebo without causing any clinically significant adverse events. A larger randomized clinical trial is warranted to prove the potential ability of hydroxychloroquine to reduce cardiovascular endpoints after myocardial infarction.

Precision Medicine Approaches to Vascular Disease: JACC Focus Seminar 2/5

In this second of a 5-part Focus Seminar series, we focus on precision medicine in the context of vascular disease. The most common vascular disease worldwide is atherosclerosis, which is the primary cause of coronary artery disease, peripheral vascular disease, and a large proportion of strokes and other disorders. Atherosclerosis is a complex genetic disease that likely involves many hundreds to thousands of single nucleotide polymorphisms, each with a relatively modest effect for causing disease. Conversely, although less prevalent, there are many vascular disorders that typically involve only a single genetic change, but these changes can often have a profound effect that is sufficient to cause disease. These are termed "Mendelian vascular diseases," which include Marfan and Loeys-Dietz syndromes. Given the very different genetic basis of atherosclerosis versus Mendelian vascular diseases, this article was divided into 2 parts to cover the most promising precision medicine approaches for these disease types.

Association of Serum IL-6 (Interleukin 6) With Functional Outcome After Intracerebral Hemorrhage

BACKGROUND AND OBJECTIVES

IL-6 (interleukin 6) is a proinflammatory cytokine and an established biomarker in acute brain injury. We sought to determine whether admission IL-6 levels are associated with severity and functional outcome after spontaneous intracerebral hemorrhage (ICH).

METHODS

We performed an exploratory analysis of the recombinant activated FAST trial (Factor VII for Acute ICH). Patients with admission serum IL-6 levels were included. Regression analyses were used to assess the associations between IL-6 and 90-day modified Rankin Scale. In secondary analyses, we used linear regression to evaluate the association between IL-6 and baseline ICH and perihematomal edema volumes.

RESULTS

Of 841 enrolled patients, we included 552 (66%) with available admission IL-6 levels (mean age 64 [SD 13], female sex 203 [37%]). IL-6 was associated with poor outcome (modified Rankin Scale, 4-6; per additional 1 ng/L, odds ratio, 1.30 [95% CI, 1.04-1.63]; P=0.02) after adjustment for known predictors of outcome after ICH and treatment group. IL-6 was associated with ICH volume after adjustment for age, sex, and ICH location, and this association was modified by location (multivariable interaction, P=0.002), with a stronger association seen in lobar (β, 12.51 [95% CI, 6.47-18.55], P<0.001) versus nonlobar (β 5.32 [95% CI, 3.36-7.28], P<0.001) location. IL-6 was associated with perihematomal edema volume after adjustment for age, sex, ICH volume, and ICH location (β 1.22 [95% CI, 0.15-2.29], P=0.03). Treatment group was not associated with IL-6 levels or outcome.

CONCLUSIONS

In the FAST trial population, higher admission IL-6 levels were associated with worse 90-day functional outcome and larger ICH and perihematomal edema volumes.