Pathogenic pathways and therapeutic targets of inflammation in heart diseases: A focus on Interleukin-1

Hypercholesterolemia and inflammation-Cooperative cardiovascular risk factors

BACKGROUND

Maintaining low concentrations of plasma low-density lipoprotein cholesterol (LDLc) over time decreases the number of LDL particles trapped within the artery wall, slows the progression of atherosclerosis and delays the age at which mature atherosclerotic plaques develop. This substantially reduces the lifetime risk of atherosclerotic cardiovascular disease (ASCVD) events. In this context, plaque development and vulnerability result not only from lipid accumulation but also from inflammation.

RESULTS

Changes in the composition of immune cells, including macrophages, dendritic cells, T cells, B cells, mast cells and neutrophils, along with altered cytokine and chemokine release, disrupt the equilibrium between inflammation and anti-inflammatory mechanisms at plaque sites. Considering that it is not a competition between LDLc and inflammation, but instead that they are partners in crime, the present narrative review aims to give an overview of the main inflammatory molecular pathways linked to raised LDLc concentrations and to describe the impact of lipid-lowering approaches on the inflammatory and lipid burden. Although remarkable changes in LDLc are driven by the most recent lipid lowering combinations, the relative reduction in plasma C-reactive protein appears to be independent of the magnitude of LDLc lowering.

CONCLUSION

Identifying clinical biomarkers of inflammation (e.g. interleukin-6) and possible targets for therapy holds promise for monitoring and reducing the ASCVD burden in suitable patients.

Air pollution and coronary atherosclerosis

The recently introduced concept of 'exposome' emphasizes the impact of non-traditional threats onto cardiovascular health. Among these, air pollutants - particularly fine particulate matter < 2.5 μm (PM2.5) - have emerged as significant environmental risk factors for cardiovascular disease and mortality. PM2.5 exposure has been shown to induce endothelial dysfunction, chronic low-grade inflammation, and cardiometabolic impairment, contributing to the development and destabilization of atherosclerotic plaques. Both short- and long-term exposure to air pollution considerably increase the incidence of ischemic heart disease (IHD)-related events, with clinical evidence linking pollution to higher mortality and adverse prognosis, especially in vulnerable populations. In this review, we explore the mechanistic pathways through which air pollutants exacerbate atherosclerotic cardiovascular disease (ASCVD) and discuss their clinical impact.Furthermore, special attention will be directed to the outcomes and prognosis of patients with pollution-aggravated coronary atherosclerosis, as well as the potential role of targeted public health interventions.

The relationship between inflammatory factors and heart failure: evidence based on bidirectional Mendelian randomization analysis

Objective

Inflammatory factors play a crucial role in the onset and progression of heart failure. To further explore the causal relationship between inflammatory factors and heart failure, we employed bidirectional Mendelian randomization analysis to investigate the causal links between 91 inflammatory cytokines and heart failure.

Methods

We conducted our study using the bidirectional Mendelian randomization approach. Data on 91 inflammatory factors were sourced from large-scale public genome-wide association study databases, while heart failure data were obtained from the FINNGEN database. The relationships between inflammatory factors and heart failure were evaluated using five methods: MR-Egger regression model, Inverse Variance Weighted method, Simple mode model, Weighted mode model, and Weighted median. Results were subjected to FDR multiple testing correction, and significant findings were discussed in detail. To enhance the robustness of our findings, various sensitivity analyses were conducted, including MR Egger intercept, MR-PRESSO and Cochran Q test.

Results

Our forward Mendelian randomization study indicated that, of the 91 inflammatory factors examined, seven showed a causal relationship with heart failure. Four of these factors were significantly causally related to the incidence of heart failure: CXCL9 and IFN-γ as promotive factors, and LIFR and UPA as potential protective factors. Three inflammatory factors had a potential causal relationship with heart failure, with DNER as a potential protective factor, and MMP-1 and CD6 as potential promotive factors. Reverse Mendelian randomization suggested that the onset of heart failure might potentially influence the levels of four inflammatory factors, with ARTN and FGF5 decreasing after the onset of heart failure, and SLAM and MMP-10 increasing. Additionally, reliability tests of this Mendelian randomization, including MR-Egger intercept and MR-PRESSO tests, revealed no evidence of pleiotropy, and Cochran's Q test also confirmed the reliability of our results.

Conclusion

We identified CXCL9, IFN-γ, LIFR, and UPA as potential inflammatory factors associated with heart failure through forward Mendelian randomization. These findings suggest potential targets but require further validation.

Novel Therapeutics and Upcoming Clinical Trials Targeting Inflammation in Cardiovascular Diseases

Cardiovascular disease (CVD) remains a major health burden despite significant therapeutic advances accomplished over the last decades. It is widely and increasingly recognized that systemic inflammation not only represents a major cardiovascular risk and prognostic factor but also plays key pathogenic roles in CVD development and progression. Despite compelling preclinical evidence suggesting large potential of anti-inflammatory pharmacological interventions across numerous CVDs, clinical translation remains incomplete, mainly due to (1) yet undefined molecular signaling; (2) challenges of safety and efficacy profile of anti-inflammatory drugs; and (3) difficulties in identifying optimal patient candidates and responders to anti-inflammatory therapeutics, as well as optimal therapeutic windows. Randomized controlled trials demonstrated the safety/efficacy of canakinumab and colchicine in secondary cardiovascular prevention, providing confirmation for the involvement of a specific inflammatory pathway (NLRP3 [NACHT, LRR, and PYD domain-containing protein 3] inflammasome/IL [interleukin]-1β) in atherosclerotic CVD. Colchicine was recently approved by the US Food and Drug Administration for this indication. Diverse anti-inflammatory drugs targeting distinct inflammatory pathways are widely used for the management of other CVDs including myocarditis and pericarditis. Ongoing research efforts are directed to implementing anti-inflammatory therapeutic strategies across a growing number of CVDs, through repurposing of available anti-inflammatory drugs and development of novel anti-inflammatory compounds, which are herein concisely discussed. This review also summarizes the main characteristics and findings of completed and upcoming randomized controlled trials directly targeting inflammation in CVDs, and discusses major challenges and future perspectives in the exciting and constantly expanding landscape of cardioimmunology.

Understanding immune-mediated titanium allergy to in situ orthopaedic implants: a narrative review of the current literature

INTRODUCTION

Clinical recognition of potential immune-mediated allergic responses to implanted metal devices is increasing. For orthopaedic implants, while 'pure' compounds are used in specific circumstances, the majority of components are alloys - a combination of two or more distinct metals. Titanium is found commonly in many orthopaedic devices and is often championed as a 'hypoallergenic' option or inclusion. In the absence of a relevant previously published summary on the topic, this paper explores the current state-of-understanding of titanium allergy and proposes a patient management algorithm whereby such immune reactions are clinically-suggested.

METHODS

A structured, systematic literature review was performed following PRISMA search principles to provide a contemporary summary-of-understanding in this area and to highlight clinical and knowledge deficiencies.

RESULTS

Thirty-five topic-related articles were identified, the majority reflecting small case series' or proof-of-concept studies. The general standard of scientific evidence available was poor. Justification for arthroplasty utilization of titanium as a 'hypoallergenic' option is largely extrapolated from non-orthopaedic domains.

CONCLUSIONS

Both ionic and conjugated titanium particles released from implant surfaces have the potential to trigger innate immune responses and true allergy. There exists no simple, high-sensitivity, screening test for titanium allergy. Conventional skin-patch testing is unreliable due to poor dermal penetration. Given established lymphocyte and macrophage activation pathways for allergy responses, in vitro methods using both cell-types show diagnostic promise. Surgical biopsy analysis from host-implant interfaces remains the contemporary 'gold-standard', however this represents an invasive, costly and highly-specialized approach not readily available in most settings. Further research to establish reliable/accessible diagnostic methods are indicated.

Current understanding and management of cardiovascular involvement in rheumatic immune-mediated inflammatory diseases

Immune-mediated inflammatory diseases (IMIDs) are a spectrum of disorders of overlapping immunopathogenesis, with a prevalence of up to 10% in Western populations and increasing incidence in developing countries. Although targeted treatments have revolutionized the management of rheumatic IMIDs, cardiovascular involvement confers an increased risk of mortality and remains clinically under-recognized. Cardiovascular pathology is diverse across rheumatic IMIDs, ranging from premature atherosclerotic cardiovascular disease (ASCVD) to inflammatory cardiomyopathy, which comprises myocardial microvascular dysfunction, vasculitis, myocarditis and pericarditis, and heart failure. Epidemiological and clinical data imply that rheumatic IMIDs and associated cardiovascular disease share common inflammatory mechanisms. This concept is strengthened by emergent trials that indicate improved cardiovascular outcomes with immune modulators in the general population with ASCVD. However, not all disease-modifying therapies that reduce inflammation in IMIDs such as rheumatoid arthritis demonstrate equally beneficial cardiovascular effects, and the evidence base for treatment of inflammatory cardiomyopathy in patients with rheumatic IMIDs is lacking. Specific diagnostic protocols for the early detection and monitoring of cardiovascular involvement in patients with IMIDs are emerging but are in need of ongoing development. This Review summarizes current concepts on the potentially targetable inflammatory mechanisms of cardiovascular pathology in rheumatic IMIDs and discusses how these concepts can be considered for the diagnosis and management of cardiovascular involvement across rheumatic IMIDs, with an emphasis on the potential of cardiovascular imaging for risk stratification, early detection and prognostication.

Clinical Utility of Rilonacept for the Treatment of Recurrent Pericarditis: Design, Development, and Place in Therapy

Recurrent pericarditis (RP) has been traditionally regarded as a "nightmare" for both clinicians and patients. Until approximately a decade ago, available treatments were thin on the ground with non-steroidal anti-inflammatory medications, glucocorticoids, colchicine, and classical immunosuppressants being the only options. The first important step in the tale of RP was the advent of colchicine in clinical practice, which has been shown to halve the rate of first and subsequent pericarditis recurrences. The second major breakthrough advance in this setting was the introduction of interleukin-1 inhibitors based on the recently unveiled autoinflammatory nature of pericarditis. At present, anti-interleukin-1 inhibitors available for clinical use in patients with refractory RP include anakinra and rilonacept, with the latter having obtained FDA approval for this indication. Apart from the remarkable efficacy and good safety profile which is a common feature of all anti-interleukin-1 compounds, rilonacept has the advantage of weekly administration (instead of daily compared to anakinra) which is important in terms of adherence to treatment and improved quality of life albeit at the expense of a higher cost. This review aims to summarize the available evidence on the role of rilonacept in the treatment of RP and the reduction of the recurrences risk.

Prognostic Value of Inflammatory Cytokines in Predicting Hospital Readmissions in Heart Failure with Preserved Ejection Fraction

Purpose

The aim of this study was to explore the relationship between inflammatory cytokines and the risk of heart failure (HF) readmission in patients with heart failure with preserved ejection fraction (HFpEF).

Patients and Methods

We enrolled 429 patients with HFpEF admitted to the cardiology department in our hospital from January 2020 to July 2022. The patients were divided into the readmission or non-readmission groups according to whether they were readmitted for heart failure within 1 year of discharge. The clinical features and laboratory date of the subjects were collected and analyzed. Multivariate cox regression analysis was used to identify predictors of HF readmission. In addition, receiver operating characteristic (ROC) curves were used to determine the prognostic value of each factor.

Results

The levels of IL-1β, IL-6, IL-10, IL-17, TNF-α, NT-proBNP, heart rate, total cholesterol and NYHA class were significantly higher in the readmission group than in the non-readmission group (p < 0.05). IL-1β, IL-6, IL-17, TNF-α, NT-proBNP, heart rate and NYHA class were identified as independent predictors of HF readmission.

Conclusion

Inflammatory markers, including IL-1β, IL-6, IL-17 and TNF-α were related to the HF readmission in patients with HFpEF.

Interleukin-1 Blockers: A Paradigm Shift in the Treatment of Recurrent Pericarditis

Recurrent pericarditis is a problematic clinical condition that impairs the quality of life of the affected patients due to the need for repeated hospital admissions, emergency department visits, and complications from medications, especially glucocorticoids. Unfortunately, available treatments for recurrent pericarditis are very limited, including only a handful of medications such as aspirin/NSAIDs, glucocorticoids, colchicine, and immunosuppressants (such as interleukin-1 (IL-1) blockers, azathioprine, and intravenous human immunoglobulins). Until recently, the clinical experience with the latter class of medications was very limited. Nevertheless, in the last decade, experience with IL-1 blockers has consistently grown, and valid clinical data have emerged from randomized clinical trials. Accordingly, IL-1 blockers are a typical paradigm shift in the treatment of refractory recurrent pericarditis with a clearly positive cost/benefit ratio for those unfortunate patients with multiple recurrences. A drawback related to the above-mentioned medications is the absence of universally accepted and established treatment protocols regarding the full dose administration period and the need for a tapering protocol for individual medications. Another concern is the need for long-standing treatments, which should be discussed with the patients. The above-mentioned unmet needs are expected to be addressed in the near future, such as further insights into pathophysiology and an individualized approach to affected patients.

Renal sympathetic denervation ameliorates the activated inflammatory response through JAK-STAT pathway in a chronic obstructive sleep apnea animal model

OBJECTIVES

Obstructive sleep apnea (OSA) is known to increase the risk of cardiovascular disease and inflammation plays a significant role in this process. Renal denervation (RDN) is a novel approach aimed at reducing sympathetic nervous system activity. The role of RDN in the inflammatory response to chronic OSA (COSA) is currently unclear. The main objective was to study inflammatory mechanisms in the rabbit heart with COSA and the effects of RDN.

METHODS

Eighteen rabbits were randomized into three groups: sham control, COSA, and COSA-RDN. COSA and COSA-RDN groups received liquid silicone injections, while the sham control group received normal saline. We performed combined surgical and chemical RDN through bilateral retroperitoneal flank incisions in the COSA-RDN group after silicone injections. The inflammatory mechanisms were assessed through immunoblotting, real-time PCR, and ELISA after the experiment.

RESULTS

H&E staining showed immune cell infiltration in COSA, which decreased after RDN treatment. The level of α7nAChR was significantly reduced in COSA compared to the sham control but was restored to a similar level in the COSA-RDN group. Furthermore, the expressions of p-JAK2 and p-STAT3 were significantly reduced in COSA but showed an up-regulation following RDN treatment. Similarly, levels of the inflammatory markers IL-6, IL-1β and TNF-α were markedly increased in COSA but decreased after RDN therapy. We observed NF-κB activation in the COSA rabbit model, which decreased after RDN treatment, as evidenced by decreased NF-κB expression.

CONCLUSIONS

Our study suggests that RDN treatment may prevent COSA-associated heart inflammation via the JAK2-STAT3 signaling pathway.