A perspective on targeting inflammation and cytokine actions in atherosclerosis

Current research status and future prospects of NLRP3 inflammasome in cardiovascular diseases: a bibliometric and visualization analysis

Background

Cardiovascular disease (CVD) is a leading cause of global mortality, with atherosclerosis (AS) contributing to its pathological basis. Inflammation plays a critical role in the pathophysiological process of AS, and the NOD-like receptor protein 3 (NLRP3) inflammasome has been extensively studied in this context. This study aimed to analyze the research status of the NLRP3 inflammasome in cardiovascular disease and provide research directions for further exploration in this field.

Methods

Using the "Bibliometrix" and "CiteSpace" software, a total of 516 articles were retrieved from the Web of Science (WoS) database published between 2012 and 2023. The search query used the keywords "["CVD" OR "cardiovascular disease"] AND ["NLRP3 inflammasome "OR "NLRP3"]". Visual analysis was performed on authors, countries, institutions, journal sources, keywords, references, and future trends.

Results

A total of 516 English articles were retrieved, showing an overall upward trend in annual publication volume with slight fluctuations. China, the United States, and Europe were the countries and regions with the highest number of published articles. Among them, China had the highest article count (170), while the United States had the highest citation count (18,664), centrality score (0.43), and h-index (90), indicating its influential role in this research area. These countries also possessed elite institutions, professional researchers, and high-impact journals, making them leading contributors in this field. The main pathogenic mechanisms of the NLRP3 inflammasome in CVD were identified as "oxidative stress", "pyroptosis", and "inflammation". The most frequently studied signaling pathways included "NF-κB", "IL-1", and "C-reactive protein". The most studied disease types were coronary heart disease, atherosclerosis, metabolic syndrome, and myocardial infarction. Additionally, research on the correlation between cholesterol markers and inflammatory indicators associated with NLRP3 inflammasome in CVD risk assessment has gained significant momentum, with the main mechanism being NLRP3/IL-6/hs-CRP and cholesterol lipoproteins emerging as a major keyword in this context.

Conclusion

This study provides valuable insights into the research hotspots and emerging trends of the NLRP3 inflammasome in cardiovascular disease. The findings offer guidance for researchers and scholars in this field and facilitate the exploration of new research directions.

Cholesterol and Cytokines: Molecular Links to Atherosclerosis and Carcinogenesis

An increase of cholesterol concentration within the artery obstructs arterial blood flow once it deposits alongside the arterial wall. This results in atherosclerosis. Carcinogenesis causes a quicker clearance of vascular cholesterol to meet the demands of tumour cell development. Both illnesses have an increased concentration of pro-inflammatory cytokines in the blood. To search the comparative characteristics of cholesterol and pro-inflammatory cytokines in the pathogenesis of atherosclerosis and carcinogenesis, a comprehensive online survey using MEDLINE, Scopus, PubMed, and Google Scholar was conducted for relevant journals with key search term cholesterol and cytokines in atherosclerotic and cancerous patients. According to reports, hypercholesterolaemia related dyslipidemia causes atherosclerosis in blood arteries and hypercholesterolaemia in cell nucleus is a reason for developing carcinogenesis. It is also noted that pro-inflammatory cytokines are involved in both of the aforementioned pathogenesis. Changes in anti-inflammatory cytokines are only the characteristic features of each kind. Thus, Cholesterol and pro-inflammatory cytokines are intensely interlinked in the genesis of atherosclerotic and carcinogenic consequences.

Inhibition Effects of Nippostrongylus brasiliensis and Its Derivatives against Atherosclerosis in ApoE-/- Mice through Anti-Inflammatory Response

Atherosclerosis (AS) is a dominant and growing cause of death and disability worldwide that involves inflammation from its inception to the emergence of complications. Studies have demonstrated that intervention with helminth infections or derived products could modulate the host immune response and effectively prevent or mitigate the onset and progression of inflammation-related diseases. Therefore, to understand the molecular mechanisms underlying the development of atherosclerosis, we intervened in ApoE-/- mice maintained on a high-fat diet with Nippostrongylus brasiliensis (N. brasiliensis) infection and immunized with its derived products. We found that N. brasiliensis infection and its derived proteins had suitable protective effects both in the initial and progressive stages of atherosclerosis, effectively reducing aortic arch plaque areas and liver lipid contents and downregulating serum LDL levels, which may be associated with the significant upregulation of serum anti-inflammatory cytokines (IL-10 and IL-4) and the down-regulation of proinflammatory cytokines (TNF-α and IFN-γ) in the serum. In conclusion, these data highlighted the effective regulatory role of N. brasiliensis and its derived proteins in the development and progression of atherosclerosis. This could provide a promising new avenue for the prevention and treatment of atherosclerosis.

Relationship Between Monocyte-to-Lymphocyte Ratio as Well as Other Leukocyte-Derived Ratios and Carotid Plaques in Patients with Coronary Heart Disease: A RCSCD-TCM Study

Purpose

This study explored the relationship between monocyte-to-lymphocyte ratio (MLR) as well as other leukocyte-derived ratios and carotid plaques in patients with coronary heart disease (CHD).

Patients and Methods

A total of 12,093 patients with CHD were selected as research participants. Leukocyte-derived ratios assessed in this study included neutrophil-to-lymphocyte ratio (NLR), derived NLR (dNLR), MLR, platelet-to-lymphocyte ratio (PLR), white blood cell-to-mean platelet volume ratio (WMR), lymphocyte×neutrophil/10⁴ ratio (MNM), systemic immune inflammation index (SII), and systemic inflammation response index (SIRI). Leukocyte-derived ratios were divided into four groups according to quarters. Logistic regression analysis was performed to evaluate the relationship between leukocyte-derived ratios and the incidence, number, and echo characteristics of carotid plaques in patients with CHD. Further analysis was performed after adjusting for confounding factors.

Results

Among the 12,093 participants, 71.7% had carotid plaques. After adjusting for confounding factors, MLR, NLR, dNLR, PLR, SII, SIRI, and WMR were found to be associated with carotid plaque formation. Among them, MLR had the strongest association with the incidence of carotid plaques (odd ratio[OR]:1.889; 95% confidence interval[CI]:1.406–2.539) and hyperechoic plaques (OR:2.024; 95% CI:1.481–2.767). When MLR was viewed as a categorical variable, the risk of carotid plaque formation in Q4 was 1.4 times higher than that in Q1. The relationship between MLR and carotid plaques in females (OR:2.250; 95% CI:1.458–3.473) was stronger than that in males (OR: 1.638; 95% CI:1.102–-2.436). The relationship between MLR and carotid plaques in patients younger than 65 years (OR:3.597; 95% CI:2.379–5.439) was stronger than that in those older than 65 years (OR:1.577; 95% CI:1.046–2.378).

Conclusion

Leukocyte-derived ratios were related to the incidence, number, and echo characteristics of carotid plaques. In particular, MLR, an inflammatory biomarker that encompasses innate and adaptive immunity, may be of great value in revealing the incidence and echo characteristics of plaques.

Neutrophil Counts, Neutrophil-to-Lymphocyte Ratio, and Systemic Inflammatory Response Index (SIRI) Predict Mortality after Off-Pump Coronary Artery Bypass Surgery

Background: Several perioperative inflammatory markers are postulated to be significant factors for long-term survival after off-pump coronary artery bypass surgery (OPCAB). Hematological parameters, whether single or combined as indices, provide higher predictive values. Methods: The study group comprised 538 consecutive patients (125 (23%) females and 413 (77%) males) with a mean age of 65 ± 9 years, who underwent OPCAB with a mean follow-up time of 4.7 ± 1.7 years. This single-center retrospective analysis included perioperative inflammatory markers such as the neutrophil-to-lymphocyte ratio (NLR), systemic inflammatory response index (SIRI), aggregate index of systemic inflammation (AISI), and systemic inflammatory index (SII). Results: Multivariable analysis identified levels of neutrophils above 4.3 × 109/L (HR 13.44, 95% CI 1.05−3.68, p = 0.037), values of SIRI above 5.4 (HR 0.29, 95% CI 0.09−0.92, p = 0.036) and values of NLR above 3.5 (HR 2.21, 95% CI 1.48−3.32, p < 0.001) as being significant predictors of long-term mortality. The multifactorial models revealed the possibility of strong prediction by combining preoperative factors (COPD, stroke, PAD, and preoperative PLR) and postoperative neutrophil counts (p = 0.0136) or NLR (p = 0.0136) or SIRI (p = 0.0136). Conclusions: Among the postoperative inflammatory indices, the levels of neutrophils, NLR, and SIRI are the most prominent markers for long-term survival after off-pump coronary artery bypass surgery, when combined with preoperative characteristics.

Probing Inflammasome Activation in Atherosclerosis

Atherosclerosis is driven by chronic inflammation in all stages of the disease. Inflammation is fueled by elevated levels of pro-inflammatory cytokines. Interleukins (IL) are cytokines of particular importance in atherosclerosis, due to their key involvement in various pro-atherogenic processes, including infiltration of immune cells to the lesion, stimulation of the production of other pro-inflammatory mediators by other sources, and generation of lipid laden foam cells, all of which contribute to plaque development and progression. Various stimuli that are abundant in atherosclerotic plaques, including oxidized low-density lipoprotein, cholesterol crystals and reactive oxygen species can trigger inflammasome activation. Importantly, activation of the nucleotide oligomerization domain leucine-rich repeat and pyrin domain containing protein 3 (NLRP3) inflammasome activates the caspase-1 protease and results in the generation and release of potent pro-inflammatory cytokines, IL-1β and IL-18. Both cytokines are influential in driving chronic inflammation and atherogenesis. This chapter describes the use of enzyme-linked immunosorbent assay (ELISA) and Western blot to quantify these cytokines in cell supernatant and lysate respectively, after stimulating inflammasome activation in cultured cells.

Evaluation of Plaque Burden and Lipid Content in Atherosclerotic Plaques

Atherosclerosis is a chronic inflammatory disease characterized by the formation of lipid-rich, fibrous plaques within the arterial wall of medium and large arteries. Plaques prone to rupture are typically rich in lipids and pro-inflammatory markers. Cells within the plaque can take up lipids via different mechanisms leading to the formation and accumulation of lipid-rich foam cells, a key hallmark of the disease. Evaluation of plaque burden and lipid content is hence important to determine disease progression and severity. This chapter describes the most commonly used staining methods that enable visualization and analysis of mouse atherosclerotic plaques. These methods include en face preparation of mouse aorta, and staining sections of arteries using hematoxylin and eosin, Oil Red O, and Masson's Trichrome.

Survey of In Vitro Model Systems for Investigation of Key Cellular Processes Associated with Atherosclerosis

Atherosclerosis progression is associated with a complex array of cellular processes in the arterial wall, including endothelial cell activation/dysfunction, chemokine-driven recruitment of immune cells, differentiation of monocytes to macrophages and their subsequent transformation into lipid laden foam cells, activation of inflammasome and pro-inflammatory signaling, and migration of smooth muscle cells from the media to the intima. The use of in vitro model systems has considerably advanced our understanding of these atherosclerosis-associated processes and they are also often used in drug discovery and other screening platforms. This chapter will describe key in vitro model systems employed frequently in atherosclerosis research.

Survey of Approaches for Investigation of Atherosclerosis In Vivo

Although in vitro model systems are useful for investigation of atherosclerosis-associated processes, they represent simplification of complex events that occur in vivo, which involve interactions between many different cell types together with their environment. The use of animal model systems is important for more in-depth insights of the molecular mechanisms underlying atherosclerosis and for identifying potential targets for agents that can prevent plaque formation and even reverse existing disease. This chapter will provide a survey of such animal models and associated techniques that are routinely used for research of atherosclerosis in vivo.

Paeonol for the Treatment of Atherosclerotic Cardiovascular Disease: A Pharmacological and Mechanistic Overview

With improvement in living standards and average life expectancy, atherosclerotic cardiovascular disease incidences and mortality have been increasing annually. Paeonia suffruticosa, a natural herb, has been used for the treatment of atherosclerotic cardiovascular disease for thousands of years in Eastern countries. Paeonol is an active ingredient extracted from Paeonia suffruticosa. Previous studies have extensively explored the clinical benefits of paeonol. However, comprehensive reviews on the cardiovascular protective effects of paeonol have not been conducted. The current review summarizes studies reporting on the protective effects of paeonol on the cardiovascular system. This study includes studies published in the last 10 years. The biological characteristics of Paeonia suffruticosa, pharmacological mechanisms of paeonol, and its toxicological and pharmacokinetic characteristics were explored. The findings of this study show that paeonol confers protection against atherosclerotic cardiovascular disease through various mechanisms, including inflammation, platelet aggregation, lipid metabolism, mitochondria damage, endoplasmic reticulum stress, autophagy, and non-coding RNA. Further studies should be conducted to elucidate the cardiovascular benefits of paeonol.

Protective effects of a unique combination of nutritionally active ingredients on risk factors and gene expression associated with atherosclerosis in C57BL/6J mice fed a high fat diet

Atherosclerosis, an inflammatory disorder of the vasculature and the underlying cause of cardiovascular disease, is responsible for one in three global deaths. Consumption of active food ingredients such as omega-3 polyunsaturated fatty acids, flavanols and phytosterols has many beneficial effects on cardiovascular disease. However, their combined actions on the risk factors for atherosclerosis remains poorly understood. We have previously shown that a formulation containing each of these active components at physiologically relevant doses modulated several monocyte/macrophage processes associated with atherosclerosis in vitro, including inhibition of cytokine-induced pro-inflammatory gene expression, chemokine-driven monocyte migration, expression of M1 phenotype markers, and promotion of cholesterol efflux. The objectives of the present study were to investigate whether the protective actions of the formulation extended in vivo and to delineate the potential underlying mechanisms. The formulation produced several favourable changes, including higher plasma levels of HDL and reduced levels of macrophages and myeloid-derived suppressor cells in the bone marrow. The mRNA expression of liver-X-receptor-α, peroxisome proliferator-activated receptor-γ and superoxide dismutase-1 was induced in the liver and that of interferon-γ and the chemokine (C-X-C motif) ligand 1 decreased, thereby suggesting the potential mechanisms for many beneficial effects. Other changes were also observed such as increased plasma levels of triglycerides and lipid peroxidation that may reflect potential activation of brown fat. This study provides new insights into the protective actions and the potential underlying mechanisms of the formulation in vivo, particularly in relation to risk factors together with changes in systemic inflammation and hepatic lipid alterations associated with atherosclerosis and metabolic syndrome, and supports further assessments in human trials.

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

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

Blockage of interleukin-1β with canakinumab in patients with Covid-19

There is the urgent need to study the effects of immunomodulating agents as therapy for Covid-19. An observational, cohort, prospective study with 30 days of observation was carried out to assess clinical outcomes in 88 patients hospitalized for Covid-19 pneumonia and treated with canakinumab (300 mg sc). Median time from diagnosis of Covid-19 by viral swab to administration of canakinumab was 7.5 days (range 0-30, IQR 4-11). Median PaO2/FiO2 increased from 160 (range 53-409, IQR 122-210) at baseline to 237 (range 72-533, IQR 158-331) at day 7 after treatment with canakinumab (p < 0.0001). Improvement of oxygen support category was observed in 61.4% of cases. Median duration of hospitalization following administration of canakinumab was 6 days (range 0-30, IQR 4-11). At 7 days, 58% of patients had been discharged and 12 (13.6%) had died. Significant differences between baseline and 7 days were observed for absolute lymphocyte counts (mean 0.60 vs 1.11 × 109/L, respectively, p < 0.0001) and C-reactive protein (mean 31.5 vs 5.8 mg/L, respectively, p < 0.0001).Overall survival at 1 month was 79.5% (95% CI 68.7-90.3). Oxygen-support requirements improved and overall mortality was 13.6%. Confirmation of the efficacy of canakinumab for Covid-19 warrants further study in randomized controlled trials.