Circulating interleukins in relation to coronary artery disease, atrial fibrillation and ischemic stroke and its subtypes: A two-sample Mendelian randomization study

Unique cardiometabolic factors in women that contribute to modified cardiovascular disease risk

Major risk factors of cardiovascular disease (CVD) include hypertension, obesity, diabetes mellitus and metabolic syndrome; all of which are considered inflammatory conditions. Women are disproportionately affected by inflammatory conditions, with sex differences emerging as early as adolescence. Hormonal fluctuations associated with reproductive events such as menarche, pregnancy and menopause, are hypothesized to promote a pro-inflammatory state in women. Moreover, women who have experienced inflammatory-type conditions such as polycystic ovarian syndrome (PCOS), gestational diabetes or pre-eclampsia, have a cardiometabolic phenotype that pre-disposes to increased risk of myocardial infarction, stroke and coronary heart disease. Women with no notable CVD risk factors are often relatively protected from CVD pre-menopause; but overtake men in risk of major cardiovascular events when the cardiovascular protective effects of oestrogen begin to wane. Sex differences and female-specific factors have long been considered challenging to study and this has led to an underrepresentation of females in clinical trials and lack of female-specific data from pre-clinical studies. However, there is now a clear prerogative to include females at all stages of research, despite inherent complexities and potential variability in data. This review explores recent advancements in our understanding of CVD in women. We summarise the underlying factors unique to women that can promote CVD risk factors, ultimately contributing to CVD burden and the emerging therapies aimed to combat this.

Use of Neutrophil-to-Lymphocyte Ratio to Predict In-Hospital Mortality in Patients Admitted with Acute Decompensation of Atrial Fibrillation

Background/Objectives: The prevalence of atrial fibrillation (AF) has been on the rise over the last 20 years. It is considered to be the most common cardiac arrhythmia and is associated with significant morbidity and mortality. The need for in-hospital management of patients having AF is increasing. Acute decompensation of cardiac rhythm is an indication for hospital admission. In the existing literature, several studies on different pathologies have observed that the risk of death was greater for patients with an increased neutrophil-to-lymphocyte ratio (NLR) and suggested that the NLR can be a useful biomarker to predict in-hospital mortality. This study aims to evaluate the link between the neutrophil-to-lymphocyte ratio at admission and death among the patients admitted to the medical ward for the acute manifestation of AF, and to gain a better understanding of how we can predict in-hospital all-cause death based on the NLR for these patients. Methods: A single-center retrospective study in an academic medical clinic was conducted. We analyzed if the NLR at in-hospital admission can be related to in-hospital mortality among the patients admitted for AF at the Medical Ward of Municipal Emergency University Hospital Timisoara between 2015 and 2016. After identifying a total of 1111 patients, we divided them into two groups: in-hospital death patients and surviving patients. We analyzed the NLR in both groups to determine if it is related to in-hospital mortality or not. One patient was excluded because of missing data. Results: Our analysis showed that patients who died during in-hospital admission had a significantly higher NLR compared to those who survived (p < 0.0001, 95% CI (1.54 to 3.48)). The NLR was found to be an independent predictor of in-hospital death among patients with AF, even for the patients with no raised level of blood leukocytes (p < 0.0001, 95% CI (0.6174 to 3.0440)). Additionally, there was a significant correlation between the NLR and the risk of in-hospital death for patients admitted with decompensated AF (p < 0.0001), with an area under the ROC curve of 0.745. Other factors can increase the risk of death for these patients (such as the personal history of stroke, HAS-BLED score, and age). Conclusions: The NLR is a useful biomarker to predict in-hospital mortality in patients with AF and can predict the risk of death with a sensitivity of 72.8% and a specificity of 70.4%. Further studies are needed to determine the clinical utility of the NLR in risk stratification and management of patients with AF.

Interleukin-6 signaling pathway in Mendelian randomization: A 10-year bibliometric analysis

Interleukin 6 (IL-6), a pleiotropic cytokine, is crucial in a variety of inflammatory and immunological disorders. In recent years, mendelian randomization, which is a widely used and successful method of analyzing causality, has recently been investigated for the relationship between the IL-6 pathway and related diseases. However, no studies have been conducted to review the research hotspots and trends in the field of IL-6 signaling pathway in Mendelian randomization. In this study, the Web of Science Core Collection (WoSCC) served as our literature source database to gather articles about the IL-6 signaling pathway in Mendelian randomization from 2013 to 2023. VOSviewer (version 1.6.18), Microsoft Excel 2021, and Scimago Graphica were employed for bibliometric and visualization analysis. A total of 164 documents that were written by 981 authors coming from 407 institutions across 41 countries and published in 107 journals were located from January 2013 to August 2023. With 64 and 25, respectively, England and the University of Bristol had the highest number of publications. Frontiers in Immunology is the most prolific journal, and Golam M Khandaker has published the highest number of significant articles. The most co-cited article was an article entitled the interleukin-6 receptor as a target for prevention of coronary-heart-disease: a Mendelian randomization analysis, written by Daniel I Swerdlow. The most popular keywords were "mendelian randomization," "interleukin-6," "il-6," "c-reactive protein," "association," "coronary-heart-disease," "inflammation," "instruments," "risk," "rheumatoid arthritis," "depression." The full extent of the existing literature over the last 10 years is systematically revealed in this study, which can provide readers with a valuable reference for fully comprehending the research hotspots and trends in the field of IL-6 signaling pathway in Mendelian randomization.

Genetic Evidence for the Causal Association of Circulating Cytokines and Growth Factors With Coronary Artery Disease

BACKGROUND

Observational studies have suggested the potential role of inflammatory factors in the risk of coronary artery disease (CAD). We aimed to perform 2-sample Mendelian randomization (MR) analyses to assess the causal association between circulating cytokines/growth factors and CAD.

METHODS AND RESULTS

The instrumental variables for 28 circulating cytokines and growth factors were identified from a genome-wide association study of 8293 European participants. Summary-level data on CAD were derived from a large genome-wide association study (71 602 cases and 260 875 controls). We used the inverse-variance-weighted and Wald ratio methods as our main MR methods. The weighted median, simple median, maximum likelihood, MR pleiotropy residual sum and outlier, and MR-Egger methods were performed as sensitivity analyses. Genetic colocalization analyses were conducted to validate the robustness of our MR findings. We found that genetically predicted circulating levels of macrophage migration inhibitory factor were associated with an increased risk of CAD at the Bonferroni-adjusted level of significance (P<1.79×10-3). The odds ratio was 1.20 (95% CI, 1.08-1.33; P=6.83×10-4) per 1-SD increase in macrophage migration inhibitory factor. Colocalization analyses supported our MR findings. Additionally, we found suggestive evidence between the genetic effects of stem cell growth factor-β and the risk of CAD (odds ratio, 0.95 [95% CI, 0.91-0.98]; P=0.007).

CONCLUSIONS

Our findings suggested a risk-increasing effect of macrophage migration inhibitory factor level on the development of CAD. The roles of these inflammatory factors for CAD warrant further investigation.

Mendelian randomization for cardiovascular diseases: principles and applications

Large-scale genome-wide association studies conducted over the last decade have uncovered numerous genetic variants associated with cardiometabolic traits and risk factors. These discoveries have enabled the Mendelian randomization (MR) design, which uses genetic variation as a natural experiment to improve causal inferences from observational data. By analogy with the random assignment of treatment in randomized controlled trials, the random segregation of genetic alleles when DNA is transmitted from parents to offspring at gamete formation is expected to reduce confounding in genetic associations. Mendelian randomization analyses make a set of assumptions that must hold for valid results. Provided that the assumptions are well justified for the genetic variants that are employed as instrumental variables, MR studies can inform on whether a putative risk factor likely has a causal effect on the disease or not. Mendelian randomization has been increasingly applied over recent years to predict the efficacy and safety of existing and novel drugs targeting cardiovascular risk factors and to explore the repurposing potential of available drugs. This review article describes the principles of the MR design and some applications in cardiovascular epidemiology.

Apolipoprotein B and interleukin 1 receptor antagonist: reversing the risk of coronary heart disease

Aims

Epidemiological evidence for the link of interleukin 1 (IL-1) and its inhibition with cardiovascular diseases (CVDs) remains controversial. We aim to investigate the cardiovascular effects of IL-1 receptor antagonist (IL-1Ra) and underlying mechanisms.

Methods

Genetic variants identified from a genome-wide association study involving 30,931 individuals were used as instrumental variables for the serum IL-1Ra concentrations. Genetic associations with CVDs and cardiometabolic risk factors were obtained from international genetic consortia. Inverse-variance weighted method was utilized to derive effect estimates, while supplementary analyses employing various statistical approaches.

Results

Genetically determined IL-1Ra level was associated with increased risk of coronary heart disease (CHD; OR, 1.07; 95% CI: 1.03-1.17) and myocardial infarction (OR, 1.13; 95% CI: 1.04-1.21). The main results remained consistent in supplementary analyses. Besides, IL-1Ra was associated with circulating levels of various lipoprotein lipids, apolipoproteins and fasting glucose. Interestingly, observed association pattern with CHD was reversed when adjusting for apolipoprotein B (OR, 0.84; 95%CI: 0.71-0.99) and slightly attenuated on accounting for other cardiometabolic risk factors. Appropriate lifestyle intervention was found to lower IL-1Ra concentration and mitigate the heightened CHD risk it posed.

Conclusion

Apolipoprotein B represents the key driver, and a potential target for reversal of the causal link between serum IL-1Ra and increased risk of CHD/MI. The combined therapy involving IL-1 inhibition and lipid-modifying treatment aimed at apolipoprotein B merit further exploration.

Therapeutic role of interleukin-1 receptor antagonist in pancreatic diseases: mendelian randomization study

Background

The interleukin-1 pathway has been linked to pancreatic diseases. We applied the Mendelian randomization approach to explore whether higher interleukin-1 receptor antagonist (IL-1RA) levels reduce the risk of acute and chronic pancreatitis and pancreatic cancer.

Methods

Genetic variants associated with blood IL-1RA levels at the genome-wide significance level and located 5MB downstream or upstream of the IL1RN gene were extracted from a genome-wide meta-analysis of 21,758 participants. After pruning, genetic variants without linkage disequilibrium were used as genetic instrument for IL-1RA. Summary-level data on acute and chronic pancreatitis and pancreatic cancer were obtained from the UK Biobank and FinnGen studies. The associations were meta-analyzed for one outcome from two sources.

Results

Genetically predicted higher levels of IL-1RA were associated with a lower risk of acute and chronic pancreatitis and pancreatic cancer. In the meta-analysis of UK Biobank and FinnGen, the combined odds ratio was 0.87 (95% confidence interval [CI] 0.77-0.97, P=0.003) for acute pancreatitis, 0.73 (95% CI 0.65-0.82, P=2.93×10-8) for chronic pancreatitis, and 0.86 (95% CI 0.77-0.96, P=0.009) for pancreatic cancer per one standard deviation increment in genetically predicted levels of IL-1RA.

Conclusion

This study suggests a protective role of IL-1RA in three major pancreatic diseases, which hints the therapeutic potentials of IL-1RA in pancreatic diseases.

The bidirectional association between atrial fibrillation and myocardial infarction

Atrial fibrillation (AF) is associated with an increased risk of myocardial infarction (MI) and vice versa. This bidirectional association relies on shared risk factors as well as on several direct and indirect mechanisms, including inflammation, atrial ischaemia, left ventricular remodelling, myocardial oxygen supply-demand mismatch and coronary artery embolism, through which one condition can predispose to the other. Patients with both AF and MI are at greater risk of stroke, heart failure and death than patients with only one of the conditions. In this Review, we describe the bidirectional association between AF and MI. We discuss the pathogenic basis of this bidirectional relationship, describe the risk of adverse outcomes when the two conditions coexist, and review current data and guidelines on the prevention and management of both conditions. We also identify important gaps in the literature and propose directions for future research on the bidirectional association between AF and MI. The Review also features a summary of methodological approaches for the study of bidirectional associations in population-based studies.

Proteome-Wide Mendelian Randomization Analysis Identified Potential Drug Targets for Atrial Fibrillation

Background Finding effective and safe therapeutic drugs for atrial fibrillation (AF) is an important concern for clinicians. Proteome-wide Mendelian randomization analysis provides new ideas for finding potential drug targets. Methods and Results Using a proteome-wide Mendelian randomization approach, we assessed the genetic predictive causality between thousands of proteins and AF risk and found that genetically predicted plasma levels of phosphomevalonate kinase, tumor necrosis factor ligand superfamily member 12, sulfhydryl oxidase 2, interleukin-6 receptor subunit alpha, and low-affinity immunoglobulin gamma Fc region receptor II-b might decrease AF risk, while genetically predicted plasma levels of beta-mannosidase, collagen alpha-1(XV) chain, ANXA4 (annexin A4), COF2 (cofilin-2), and RAB1A (Ras-related protein Rab-1A) might increase AF risk (P<3.4×10-5). By using different Mendelian randomization methods and instrumental variable selection thresholds, we performed sensitivity analyses in 30 scenarios to test the robustness of positive findings. Replication analyses were also performed in independent samples to further avoid false-positive findings. Drugs targeting tumor necrosis factor ligand superfamily member 12, interleukin-6 receptor subunit alpha, low-affinity immunoglobulin gamma Fc region receptor II-b, and annexin A4 are approved or in development. The results of the phenome-wide Mendelian randomization analysis showed that changing the plasma levels of phosphomevalonate kinase, cofilin-2, annexin A4, Ras-related protein Rab-1A, sulfhydryl oxidase 2, and collagen alpha-1(XV) chain did not increase the risk of other diseases while decreasing the risk of AF. Conclusions We found a significant causal association between genetically predicted levels of 10 plasma proteins and AF risk. Four of these proteins have drugs targeting them that are approved or in development, and our results suggest the potential for these drugs to treat AF or cause AF. Sulfhydryl oxidase 2, low-affinity immunoglobulin gamma Fc region receptor II-b, and beta-mannosidase have not been suggested by previous laboratory or epidemiological studies to be associated with AF and may reveal new pathophysiological pathways as well as therapeutic targets for AF.

Circulating interleukins and risk of colorectal cancer: a Mendelian randomization study

BACKGROUND

Recent studies have suggested a potential causal association between Interleukins (ILs) and Colorectal Cancer (CRC), and thus, it is important to examine the causal relationship between them using a Mendelian randomization (MR) approach.

METHODS

The instrumental variables were extracted for IL-1ra, IL-6, IL-6ra, IL-8, IL-16, IL-18, IL-27 from genome-wide association studies of European ancestry. Summary statistics of CRC were also retrieved. An inverse variance-weighted MR approach was implemented as the primary method to compute overall effects from multiple instruments. Additional MR approaches and sensitivity and heterogeneity pleiotropy analyses were also conducted respectively.

RESULTS

Our analysis suggested a causal effect between an increase of IL-8 and a reduced risk of CRC (odds ratio 0.65; 95% confidence interval, 0.43-0.98; p = 0.041) and did not provide evidence for causal effects of IL-1ra, IL-6, IL-6ra, IL-16, IL-18, IL-27. Sensitivity analyses suggested the robustness of MR results and that they were unlikely to be affected by unbalanced pleiotropy or significant heterogeneity.

CONCLUSIONS

This study investigated the role of ILs in the development of CRC and we found a causal effect between an increase of IL-8 and a reduced risk of CRC but not found evidence for causal effects of IL-1ra, IL-6, IL-6ra, IL-16, IL-18, IL-27. Sensitivity analyses suggested the robustness of MR results and that they were unlikely to be affected by unbalanced pleiotropy or significant heterogeneity.

Circulating levels of cytokines and risk of cardiovascular disease: a Mendelian randomization study

Background

Epidemiological studies have linked various circulating cytokines to cardiovascular disease (CVD), which however remains uncertain whether these relationships represent causality or are due to bias. To address this question, we conducted a Mendelian randomization (MR) analysis to systematically investigate the causal effects of circulating cytokine levels on CVD development.

Methods

This study leveraged the summary statistic from respective genome-wide association study (GWAS) of 47 cytokines and four types of CVD. The cis-quantitative trait locus (cis-QTL) definition, derived from a GWAS meta-analysis comprising 31,112 participants of European descent, served as instruments for cytokines. A two-sample MR design was employed, followed by comprehensive sensitivity analyses to validate the robustness of results.

Results

The results of inverse-variance weighted method using cis-protein QTL (cis-pQTL) instruments, showed the causal effects of four cytokines (i.e., IL-1ra, MCSF, SeSelectin, SCF) on the risk of coronary artery disease (CAD). We also identified causal relationships between two cytokines (i.e., IL-2ra, IP-10) and heart failure (HF), as well as two cytokines (i.e., MCP-3, SeSelectin) and atrial fibrillation (AF), after controlling for false discovery rate (FDR). The use of cis-expression QTL (cis-eQTL) revealed additional causal associations between IL-1a, MIF and CAD, between IL-6, MIF, and HF, as well as between FGFBasic and AF. No significant sign was survived for stroke with FDR applied. Results were largely consistent across sensitivity analyses.

Conclusion

The present study provides supportive evidence that genetic predisposition to levels of certain cytokines causally affects the development of specific type of CVD. These findings have important implications for the creation of novel therapeutic strategies targeting these cytokines as a means of preventing and treating CVD.

Evaluation of the association between circulating IL-1β and other inflammatory cytokines and incident atrial fibrillation in a cohort of postmenopausal women

BACKGROUND

Inflammatory cytokines play a role in atrial fibrillation (AF). Interleukin (IL)-1β, which is targeted in the treatment of ischemic heart disease, has not been well-studied in relation to AF.

METHODS

Postmenopausal women from the Women's Health Initiative were included. Cox proportional hazards regression models were used to evaluate the association between log-transformed baseline cytokine levels and future AF incidence. Models were adjusted for body mass index, age, race, education, hypertension, diabetes, hyperlipidemia, current smoking, and history of coronary heart disease, congestive heart failure, or peripheral artery disease.

RESULTS

Of 16,729 women, 3,943 developed AF over an average of 8.5 years. Racial and ethnic groups included White (77.4%), Black/African-American (16.1%), Asian (2.7%), American Indian/Alaska Native (1.0%), and Hispanic (5.5%). Baseline IL-1β log continuous levels were not significantly associated with incident AF (HR 0.86 per 1 log [pg/mL] increase, P= .24), similar to those of other inflammatory cytokines, IL-7, IL-8, IL-10, IGF-1, and TNF-α. There were significant associations between C-reactive protein (CRP) and IL-6 with incident AF.

CONCLUSIONS

In this large cohort of postmenopausal women, there was no significant association between IL-1β and incident AF, although downstream effectors, CRP and IL-6, were associated with incident AF.

Prognostic value of interleukin-34 and interleukin-38 in patients with newly diagnosed atrial fibrillation

Background

Interleukin (IL)-34 and IL-38 are associated with cardiovascular disease (CVD). However, their involvement in atrial fibrillation (AF) and AF-associated adverse events remains uncertain. Therefore, we aimed to investigate their association with various AF prognostic factors in a cohort study and assessed their predictive value for the prognosis of patients with AF.

Methods

Patients with new-onset non-valvular AF were consecutively enrolled between 2013 and 2015 at the Department of Cardiovascular Medicine of the Southwest Hospital of the Army Medical University (Third Military Medical University) in Chongqing, China. The endpoints included stroke and all-cause mortality. The baseline levels of plasma IL-34, IL-38, NT-proBNP, high-sensitivity cardiac troponin T (hs-cTnT), and GDF-15 were measured and their correlation with AF-related adverse events were analyzed in a Cox proportional-hazards regression model. The C-statistic, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were used to evaluate the performance of the AF prognostic models. Decision curve analysis (DCA) was used to evaluate the clinical net benefit of the original and modified models.

Results

A total of 299 patients with new-onset AF were enrolled. During the median follow-up time of 28 (IQR: 27, 29) months, the higher levels of IL-34 were associated with a lower risk of stroke, and the higher levels of IL-38 were associated with an increased risk of all-cause death (all adjusted P < 0.05). In addition, elevated hs-cTnT and NT-proBNP concentrations were associated with a higher risk of stroke and all-cause mortality (all adjusted P < 0.05). Furthermore, the CHA₂DS₂-VASc score combined with IL-38 and NT-proBNP significantly improved the C-statistic, IDI, and NRI (all P < 0.01). There was no statistically significant difference (all P > 0.05) in the discrimination power between the preference models and the ABC (age, biomarkers, and clinical history) score for the two prognostic outcomes.

Conclusion

Our results suggested that IL-34 and IL-38 were independently associated with stroke and all-cause mortality in patients with AF. Moreover, adding IL-38 and NT-proBNP to the CHA₂DS₂-VASc score significantly improved its predictive ability of AF-related all-cause death. Finally, the preference model performed equally well as the ABC score in predicting AF prognosis.

Exploring the causality between ankylosing spondylitis and atrial fibrillation: A two-sample Mendelian randomization study

Objective: To study whether ankylosing spondylitis (AS) has a causal effect on the risk of atrial fibrillation (AF) using two-sample Mendelian randomization (MR) analysis. Methods: Single nucleotide polymorphisms (SNPs) were selected as independent instrumental variables (IVs) from a GWAS study of AS. Summary data from a large-scale GWAS meta-analysis of AF was utilized as the outcome dataset. Inverse-variance weighted (IVW) model was used for the primary analysis. Multiple sensitivity and heterogeneity tests were conducted to confirm the robustness of the results. Results: In total, 18 SNPs were identified as IVs for MR analysis. Five MR methods consistently found that ankylosing spondylitis was not causally associated with atrial fibrillation (IVW: OR = 0.983 (0.894, 1.080), p = 0.718; MR-Egger: OR = 1.190 (0.973, 1.456), p = 0.109; Simple mode: OR = 0.888 (0.718, 1.098), p = 0.287; Weighted mode: OR = 0.989 (0.854, 1.147), p = 0.890; Weight median: OR = 0.963 (0.852, 1.088), p = 0.545). Leave-one-out analysis supported the stability of MR results. Both the MR-Egger intercept and MR-PRESSO method revealed the absence of horizontal pleiotropy. Conclusion: The two-sample MR analysis did not support a causal relationship between AS and the risk of AF.

Genetic Liability to Rheumatoid Arthritis in Relation to Coronary Artery Disease and Stroke Risk

OBJECTIVE

To assess the causality of the associations of rheumatoid arthritis (RA) with coronary artery disease (CAD) and stroke using the Mendelian randomization approach.

METHODS

Independent single-nucleotide polymorphisms strongly associated with RA (n = 70) were selected as instrumental variables from a genome-wide association meta-analysis including 14,361 RA patients and 43,923 controls of European ancestry. Summary-level data for CAD, all stroke, any ischemic stroke and its subtypes, intracerebral hemorrhage (ICH), and subarachnoid hemorrhage were obtained from meta-analyses of genetic studies, international genetic consortia, the UK Biobank, and the FinnGen consortium. We obtained summary-level data for common cardiovascular risk factors and related inflammatory biomarkers to assess possible mechanisms.

RESULTS

Genetic liability to RA was associated with an increased risk of CAD and ICH. For a 1-unit increase in log odds of RA, the combined odds ratios were 1.02 (95% confidence interval [1.01, 1.03]; P = 0.003) for CAD and 1.05 (95% confidence interval [1.02, 1.08]; P = 0.001) for ICH. Genetic liability to RA was associated with increased levels of tumor necrosis factor and C-reactive protein (CRP). The association with CAD was attenuated after adjustment for genetically predicted CRP levels. There were no associations of genetic liability to RA with the other studied outcomes.

CONCLUSION

This study found that genetic liability to RA was associated with an increased risk of CAD and ICH and that the association with CAD might be mediated by CRP. The heightened cardiovascular risk should be actively monitored and managed in RA patients, and this may include dampening systemic inflammation.

Cooking methods are associated with inflammatory factors, renal function, and other hormones and nutritional biomarkers in older adults

Evidence of the role of cooking methods on inflammation and metabolic health is scarce due to the paucity of large-size studies. Our aim was to evaluate the association of cooking methods with inflammatory markers, renal function, and other hormones and nutritional biomarkers in a general population of older adults. In a cross sectional analysis with 2467 individuals aged ≥ 65, dietary and cooking information was collected using a validated face-to-face dietary history. Eight cooking methods were considered: raw, boiling, roasting, pan-frying, frying, toasting, sautéing, and stewing. Biomarkers were analyzed in a central laboratory following standard procedures. Marginal effects from generalized linear models were calculated and percentage differences (PD) of the multivariable-adjusted means of biomarkers between extreme sex-specific quintiles (Q) of cooking methods consumption were computed ([Q5 − Q1/Q1] × 100). Participants’ mean age was 71.6 years (53% women). Significant PD for the highest vs lowest quintile of raw food consumption was − 54.7% for high sensitivity-C reactive protein (hs-CRP), − 11.9% for neutrophils, − 11.9% for Growth Differentiation Factor-15, − 25.0% for Interleukin-6 (IL-6), − 12.3% for urinary albumin, and − 10.3% for uric acid. PD for boiling were − 17.8% for hs-CRP, − 12.4% for urinary albumin, and − 11.3% for thyroid-stimulating hormone. Concerning pan-frying, the PD was − 23.2% for hs-CRP, − 11.5% for IL-6, − 16.3% for urinary albumin and 10.9% for serum vitamin D. For frying, the PD was a 25.7% for hs-CRP, and − 12.6% for vitamin D. For toasting, corresponding figures were − 21.4% for hs-CRP, − 11.1% for IL-6 and 10.6% for vitamin D. For stewing, the PD was 13.3% for hs-CRP. Raw, boiling, pan-frying, and toasting were associated with healthy profiles as for inflammatory markers, renal function, thyroid hormones, and serum vitamin D. On the contrary, frying and, to a less extent, stewing showed unhealthier profiles. Cooking methods not including added fats where healthier than those with added fats heated at high temperatures or during longer periods of time.

Genome-Wide Studies in Ischaemic Stroke: Are Genetics Only Useful for Finding Genes?

Ischaemic stroke is a complex disease with some degree of heritability. This means that heritability factors, such as genetics, could be risk factors for ischaemic stroke. The era of genome-wide studies has revealed some of these heritable risk factors, although the data generated by these studies may also be useful in other disciplines. Analysis of these data can be used to understand the biological mechanisms associated with stroke risk and stroke outcome, to determine the causality between stroke and other diseases without the need for expensive clinical trials, or to find potential drug targets with higher success rates than other strategies. In this review we will discuss several of the most relevant studies regarding the genetics of ischaemic stroke and the potential use of the data generated.

MiRNA21 and IL-18 levels in left atrial blood in patients with atrial fibrillation undergoing cryoablation and their predictive value for recurrence of atrial fibrillation

PURPOSE

The recurrence of atrial fibrillation (AF) after cryoablation still needs to be prioritized, including discriminating predictive indicators.

METHODS

Eighty-seven patients aged 43-83 years who underwent cryo-balloon ablation were divided into paroxysmal atrial fibrillation (PAF) and non-paroxysmal atrial fibrillation (non-PAF) groups. Baseline data, intraoperative index, and miRNA21, IL-18, NLRP3, and visfatin levels in peripheral venous blood and left atrial blood were assessed. Follow-up was performed for 6 months to observe the recurrence of AF. A Cox risk ratio model was used to analyze indicators for predicting AF recurrence.

RESULTS

The non-PAF and PAF group recurrence rates of AF were statistically different (p < 0.05) at 9/22 (40.9%) and 11/65 (16.9%), respectively. Biomarker levels in the left atrial blood were higher in the non-PAF group than in the PAF group (p < 0.05). The effects of non-PAF and levels of miRNA21 and IL-18 in left atrial serum on the recurrence of AF after cryoablation statistically differed (p < 0.05).

CONCLUSION

The levels of miRNA21 and IL-18 were higher in left atrial blood than in peripheral blood, which may be related to the severity of AF and recurrence of AF after cryoablation.

Genetically regulated gene expression and proteins revealed discordant effects

Background

Although gene-expression (GE) and protein levels are typically strongly genetically regulated, their correlation is known to be low. Here we investigate this phenomenon by focusing on the genetic background of this correlation in order to understand the similarities and differences in the genetic regulation of these omics layers.

Methods and results

We performed locus-wide association studies of 92 protein levels measured in whole blood for 2,014 samples of European ancestry and found that 66 are genetically regulated. Three female- and one male-specific effects were detected. We estimated the genetically regulated GE for all significant genes in 49 GTEx v8 tissues. A total of 7 proteins showed negative correlations with their respective GE across multiple tissues. Finally, we tested for causal links of GE on protein expression via Mendelian Randomization, and confirmed a negative causal effect of GE on protein level for five of these genes in a total of 63 gene-tissue pairs: BLMH, CASP3, CXCL16, IL6R, and SFTPD. For IL6R, we replicated the negative causal effect on coronary-artery disease (CAD), while its GE was positively linked to CAD.

Conclusion

While total GE and protein levels are only weakly correlated, we found high correlations between their genetically regulated components across multiple tissues. Of note, strong negative causal effects of tissue-specific GE on five protein levels were detected. Causal network analyses revealed that GE effects on CAD risks was in general mediated by protein levels.

Role of New Potential Biomarkers in the Risk of Thromboembolism in Atrial Fibrillation

Ischemic stroke risk in atrial fibrillation differs from patient to patient, depending on numerous variables. Many attempts have been made to translate this difference into simple numbers and to compare it to the hemorrhagic risk of anticoagulation. Different clinical scores have been studied to define a clear strategy. One score, the CHA₂DS₂-VASc score, has been extensively and successfully applied worldwide. Nevertheless, it is not yet the “perfect instrument”. Many proposals have been made to integrate its clinical parameters with some biomarkers to improve its predictive power. This short review describes some of these biomarkers and their possible implications in potentiating the efficacy of clinical scores.

Inflammatory Cytokines and Risk of Ischemic Stroke: A Mendelian Randomization Study

Background: Observational studies have revealed the association between some inflammatory cytokines and the occurrence of ischemic stroke, but the causal relationships remain unclear.

Methods: We conducted a two-sample Mendelian randomization (MR) analysis to assess the causal effects of thirty inflammatory cytokines and the risk of ischemic stroke. For exposure data, we collected genetic variants associated with inflammatory cytokines as instrumental variables (IVs) from a genome-wide association study (GWAS) meta-analysis from Finland (sample size up to 8,293). For the outcome data, we collected summary data of ischemic stroke from a large-scale GWAS meta-analysis involved 17 studies (34,217 cases and 406,111 controls). We further performed a series of sensitivity analyses as validation of primary MR results.

Results: According to the primary MR estimations and further sensitivity analyses, we established one robust association after Bonferroni correction: the odds ratio (95% CI) per unit change in genetically increased IL-4 was 0.84 (0.89–0.95) for ischemic stroke. The chemokine MCP3 showed a nominally significant association with ischemic stroke risk (OR: 0.93, 95% CI: 0.88–0.99, unadjusted p < 0.05). There was no evidence of a causal effect of other inflammatory cytokines and the risk of ischemic stroke.

Conclusions: Our study suggested that genetically increased IL-4 levels showed a protective effect on the risk of ischemic stroke, which provides important new insights into the potential therapeutic target for preventing ischemic stroke.

Genetics of common cerebral small vessel disease

Cerebral small vessel disease (cSVD) is a leading cause of ischaemic and haemorrhagic stroke and a major contributor to dementia. Covert cSVD, which is detectable with brain MRI but does not manifest as clinical stroke, is highly prevalent in the general population, particularly with increasing age. Advances in technologies and collaborative work have led to substantial progress in the identification of common genetic variants that are associated with cSVD-related stroke (ischaemic and haemorrhagic) and MRI-defined covert cSVD. In this Review, we provide an overview of collaborative studies - mostly genome-wide association studies (GWAS) - that have identified >50 independent genetic loci associated with the risk of cSVD. We describe how these associations have provided novel insights into the biological mechanisms involved in cSVD, revealed patterns of shared genetic variation across cSVD traits, and shed new light on the continuum between rare, monogenic and common, multifactorial cSVD. We consider how GWAS summary statistics have been leveraged for Mendelian randomization studies to explore causal pathways in cSVD and provide genetic evidence for drug effects, and how the combination of findings from GWAS with gene expression resources and drug target databases has enabled identification of putative causal genes and provided proof-of-concept for drug repositioning potential. We also discuss opportunities for polygenic risk prediction, multi-ancestry approaches and integration with other omics data.

Genetically Determined Inflammatory Biomarkers and the Risk of Heart Failure: A Mendelian Randomization Study

Background: Positive associations between inflammatory biomarkers and the risk of heart failure (HF) have been reported in conventional observational studies. However, the causal effects of inflammatory biomarkers on HF have not been fully elucidated. We conducted a Mendelian randomization (MR) study to examine the possible etiological roles of inflammatory biomarkers in HF. Methods: Summary statistical data for the associations between single nucleotide polymorphisms (SNPs) and C-reactive protein (CRP), fibrinogen, and components of the interleukin-1 (IL-1)-interleukin-6 (IL-6) inflammatory signaling pathway, namely, interleukin-1β (IL-1β), IL-1 receptor antagonist (IL-1ra), IL-6, and soluble IL-6 receptor (sIL-6r), were obtained from genome-wide association studies (GWASs) for individuals of European descent. The GWAS dataset of 977,323 participants of European ancestry, which included 47,309 HF cases and 930,014 controls, was collected to identify genetic variants underlying HF. A two-sample Mendelian randomization framework was implemented to examine the causality of the association between these inflammatory biomarkers and HF. Results: Our MR analyses found that genetically determined CRP and fibrinogen were not causally associated with HF risk (odds ratio [OR] = 0.93, 95% confidence interval [CI] = 0.84-1.02, p = 0.15; OR = 0.94, 95% CI = 0.55-1.58, p = 0.80, respectively). These findings remained consistent using different Mendelian randomization methods and in sensitivity analyses. For the IL-1-IL-6 pathway, causal estimates for IL-6 (OR = 0.86, 95% CI 0.81-0.91, p < 0.001), but not for IL-1β, IL-1ra, or sIL-6r, were significant. However, the association between genetically determined IL-6 and HF risk became non-significant after excluding SNPs with potential pleiotropy (OR = 0.89, 95% CI = 0.77-1.03, p = 0.12). Conclusion: Our study did not identify convincing evidence to support that CRP and fibrinogen, together with their upstream IL-1-IL-6 signaling pathway, were causally associated with HF risk.

Obesity and Cardiovascular Disease: The Emerging Role of Inflammation

Obesity is a growing public health challenge across the globe. It is associated with increased morbidity and mortality. Cardiovascular disease (CVD) is the leading cause of mortality for people with obesity. Current strategies to reduce CVD are largely focused on addressing traditional risk factors such as dyslipidemia, type 2 diabetes (T2D) and hypertension. Although this approach is proven to reduce CVD, substantial residual risk remains for people with obesity. This necessitates a better understanding of the etiology of CVD in people with obesity and alternate therapeutic approaches. Reducing inflammation may be one such strategy. A wealth of animal and human data indicates that obesity is associated with adipose tissue and systemic inflammation. Inflammation is a known contributor to CVD in humans and can be successfully targeted to reduce CVD. Here we will review the etiology and pathogenesis of inflammation in obesity associated metabolic disease as well as CVD. We will review to what extent these associations are causal based on human genetic studies and pharmacological studies. The available data suggests that anti-inflammatory treatments can be used to reduce CVD, but off-target effects such as increased infection have precluded its broad therapeutic application to date. The role of anti-inflammatory therapies in improving glycaemia and metabolic parameters is less established. A number of clinical trials are currently ongoing which are evaluating anti-inflammatory agents to lower CVD. These studies will further clarify whether anti-inflammatory agents can safely reduce CVD.

Associations Between Inflammation, Cardiovascular Regenerative Capacity, and Cardiovascular Events: A Cohort Study

Objective

Circulating progenitor cells possess immune modulatory properties and might mitigate inflammation that is characteristic of patients with coronary artery disease. We hypothesized that patients with fewer circulating progenitor cells (CPCs) will have higher inflammatory markers and worse outcomes.

Approach and Results

Patients with stable coronary artery disease were enrolled in a prospective study enumerating CPCs as CD (cluster of differentiation)-34-expressing mononuclear cells (CD34+) and inflammation as levels of IL (interleukin)-6 and high-sensitivity CRP (C-reactive protein) levels. Patients were followed for 5 years for the end points of death and myocardial infarction with repeat inflammatory biomarkers measured after a median of 2 years. In the entire cohort of 392 patients, IL-6 and high-sensitivity CRP levels remained unchanged (0.3+/-2.4 pg/mL and 0.1+/-1.0 mg/L; P=0.45) after 2 years. CPC counts (log-transformed) were inversely correlated with the change in IL-6 levels (r, -0.17; P<0.001). Using linear regression, IL-6 and high-sensitivity CRP levels declined by -0.59 (95% CI, -0.90 to -0.20) pg/mL and -0.13 (-0.28 to 0.01) mg/L per 1 log higher CPC counts after adjustment for the demographic and clinical variables, as well as medications. Using Cox models adjusted for these risk factors, a rise in 1 pg/mL of IL-6 was associated with a 11% (95% CI, 9-13) greater risk of death/myocardial infarction. We found that the change in IL6 level partly (by 40%) mediated the higher risk of adverse events among those with low CPC counts.

Conclusions

Reduced cardiovascular regenerative capacity is independently associated with progressive inflammation in patients with coronary artery disease that in turn is associated with poor outcomes.

Inflammatory Mediators of Platelet Activation: Focus on Atherosclerosis and COVID-19

Background: Atherosclerotic cardiovascular diseases are characterized by a dysregulated inflammatory and thrombotic state, leading to devastating complications with increased morbidity and mortality rates. Summary: In this review article, we present the available evidence regarding the impact of inflammation on platelet activation in atherosclerosis. Key messages: In the context of a dysfunctional vascular endothelium, structural alterations by means of endothelial glycocalyx thinning or functional modifications through impaired NO bioavailability and increased levels of von Willebrand factor result in platelet activation. Moreover, neutrophil-derived mediators, as well as neutrophil extracellular traps formation, have been implicated in the process of platelet activation and platelet-leukocyte aggregation. The role of pro-inflammatory cytokines is also critical since their receptors are also situated in platelets while TNF-α has also been found to induce inflammatory, metabolic, and bone marrow changes. Additionally, important progress has been made towards novel concepts of the interaction between inflammation and platelet activation, such as the toll-like receptors, myeloperoxidase, and platelet factor-4. The accumulating evidence is especially important in the era of the coronavirus disease-19 pandemic, characterized by an excessive inflammatory burden leading to thrombotic complications, partially mediated by platelet activation. Lastly, recent advances in anti-inflammatory therapies point towards an anti-thrombotic effect secondary to diminished platelet activation.

Platelet Mediated Inflammation in Coronary Artery Disease with Type 2 Diabetes Patients

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a well-established risk factor for the development of atherosclerotic coronary artery disease. Platelet hyperactivity and inflammation are associated with the development of coronary artery disease (CAD) in T2DM patients. We investigated the status of immune cells, platelet activation, and platelet-immune cell interactions in T2DM_CAD patients.

METHODOLOGY

The study population consisted of four groups of subjects, healthy control (CT, n = 20), T2DM (n = 44), CAD (n = 20) and T2DM_CAD (n = 38). Platelet activation, immunome profiling and platelet-immune cell interactions were analysed by flow cytometry. The circulatory levels of inflammatory cytokines/chemokines were assessed using multiplex assay.

RESULTS

Increased platelet activation and increased platelet-immune cell aggregate formation were observed in T2DM and T2DM_CAD groups compared to the control and CAD groups (p < 0.05). Our immunome profile analysis revealed, altered monocyte subpopulations and dendritic cell populations in T2DM, CAD and T2DM_CAD groups compared to the control group (p < 0.05). Furthermore, significantly increased IL-1β, IL-2, IL-4, IL-6, IL-8, IL12p70, IL-13 IL-18, CCL2, and decreased CXCL1, CCL5 levels were observed in T2DM_CAD group compared to the control group. Our ex-vivo study increased platelet-monocyte aggregate formation was observed upon D-glucose exposure in a time and concentration dependent manner.

CONCLUSION

Our data suggests that T2DM, CAD and T2DM_CAD are associated with altered immune cell populations. Furthermore, it has been confirmed that hyperglycemia induces platelet activation and forms platelet-immune cell aggregation which may lead to the release of inflammatory cytokines and chemokines and contribute to the complexity of CAD and type 2 diabetes.

Mendelian Randomization in Stroke: A Powerful Approach to Causal Inference and Drug Target Validation

Stroke is a leading cause of death and disability worldwide. However, our understanding of its underlying biology and the number of available treatment options remain limited. Mendelian randomization (MR) offers a powerful approach to identify novel biological pathways and therapeutic targets for this disease. Around ~100 MR studies have been conducted so far to explore, confirm, and quantify causal relationships between several exposures and risk of stroke. In this review, we summarize the current evidence arising from these studies, including those investigating ischemic stroke, hemorrhagic stroke, or both. We highlight the different types of exposures that are currently under study, ranging from well-known cardiovascular risk factors to less established inflammation-related mechanisms. Finally, we provide an overview of future avenues of research and novel approaches, including drug target validation MR, which is poised to have a substantial impact on drug development and drug repurposing.

A Review of Biomarkers for Ischemic Stroke Evaluation in Patients With Non-valvular Atrial Fibrillation

Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia worldwide and results in a significantly increased ischemic stroke (IS) risk. IS risk stratification tools are widely being applied to guide anticoagulation treatment decisions and duration in patients with non-valvular AF (NVAF). The CHA₂DS₂-VASc score is largely validated and currently recommended by renowned guidelines. However, this score is heavily dependent on age, sex, and comorbidities, and exhibits only moderate predictive power. Finding effective and validated clinical biomarkers to assist in personalized IS risk evaluation has become one of the promising directions in the prevention and treatment of NVAF. A number of studies in recent years have explored differentially expressed biomarkers in NVAF patients with and without IS, and the potential role of various biomarkers for prediction or early diagnosis of IS in patients with NVAF. In this review, we describe the clinical application and utility of AF characteristics, cardiac imaging and electrocardiogram markers, arterial stiffness and atherosclerosis-related markers, circulating biomarkers, and novel genetic markers in IS diagnosis and management of patients with NVAF. We conclude that at present, there is no consensus understanding of a desirable biomarker for IS risk stratification in NVAF, and enrolling these biomarkers into extant models also remains challenging. Further prospective cohorts and trials are needed to integrate various clinical risk factors and biomarkers to optimize IS prediction in patients with NVAF. However, we believe that the growing insight into molecular mechanisms and in-depth understanding of existing and emerging biomarkers may further improve the IS risk identification and guide anticoagulation therapy in patients with NVAF.

Comprehensive Analysis of the Immune Infiltrates and Aberrant Pathways Activation in Atherosclerotic Plaque

Atherosclerosis is the pathological basis of many cardiovascular and cerebrovascular diseases. The development of gene chip and high-throughput sequencing technologies revealed that the immune microenvironment of coronary artery disease (CAD) in high-risk populations played an important role in the formation and development of atherosclerotic plaques. Three gene expression datasets related to CAD were assessed using high-throughput profiling. CIBERSORT analysis revealed significant differences in five types of immune cells: activated dendritic cells (DCs), T follicular helper cells (Tfhs), resting CD4+ T cells, regulatory T cells (Tregs), and γδ T cells. Immune transcriptome analysis indicated higher levels of inflammatory markers (cytolytic activity, antigen presentation, chemokines, and cytokines) in the cases than in the controls. The level of activated DCs and the lipid clearance signaling score were negatively correlated. We observed a positive correlation between the fraction of Tfhs and lipid biosynthesis. Resting CD4+ T cells and the activity of pathways related to ossification in bone remodeling and glutathione synthesis showed a negative correlation. Gamma delta T cells negatively correlated with IL-23 signaling activity. GSEA revealed a close association with the inflammatory immune microenvironment. The present study revealed that CAD patients may have an inflammatory immune microenvironment and provides a timely update on anti-inflammatory therapies under current investigation.

Interleukin-6 and Outcomes in Acute Heart Failure: An ASCEND-HF Substudy

BACKGROUND

The inflammatory cytokine IL-6 has been previously implicated in the pathophysiology of acute decompensated heart failure (HF). Prior observations in acute HF patients have suggested that IL-6 may be associated with outcomes and modulated by nesiritide. We aimed to evaluate the associations between serial IL-6 measurements, mortality and rehospitalization in acute HF.

METHODS AND RESULTS

We analyzed the associations between IL-6 in acute HF, readmission, and mortality (30 and 180 days) using a cohort of 883 hospitalized patients from the ASCEND-HF trial (nesiritide vs placebo). Plasma IL-6 was measured at randomization (baseline), 48-72 hours, and 30 days. The median IL-6 was highest at baseline (14.1 pg/mL) and decreased at subsequent time points (7.6 pg/mL at 30 days). In a univariable Cox regression analysis, the baseline IL-6 was associated with 30- and 180-day mortality (hazard ratio per log 1.74, 95% confidence interval 1.09-2.78, P = .021; hazard ratio 3.23, confidence interval 1.18-8.86, P = .022, respectively). However, there was no association after multivariable adjustment. IL-6 at 48-72 hours was found to be independently associated with 30-day mortality (hazard ratio 8.2, confidence interval 1.2-57.5, P= .03), but not 180-day mortality in multivariable analysis that included the ASCEND-HF risk model and amino terminal pro-B-type natriuretic peptide as covariates. In comparison with placebo, nesiritide therapy was not associated with differences in serial IL-6 levels.

CONCLUSIONS

Although elevated IL-6 levels were associated with higher all-cause mortality in acute HF, no independent association with this outcome was identified at baseline or 30-day measurements. In contrast with prior reports, we did not observe any impact of nesiritide over placebo on serial IL-6 levels.

COVID-19 associated atrial fibrillation: Incidence, putative mechanisms and potential clinical implications

Coronavirus disease 2019 (COVID-19) is a novel, highly transmittable and severe strain disease, which has rapidly spread worldwide. Despite epidemiological evidence linking COVID-19 with cardiovascular diseases, little is known about whether and how COVID-19 influences atrial fibrillation (AF), the most prevalent arrhythmia in clinical practice. Here, we review the available evidence for prevalence and incidence of AF in patients infected with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and discuss disease management approaches and potential treatment options for COVID-19 infected AF patients.

Association between HindIII (rs320) variant in the lipoprotein lipase gene and the presence of coronary artery disease and stroke among the Saudi population

Lipoprotein Lipase (LPL) is known to be a key enzyme for lipid metabolism specifically in an enzymatic glycoprotein which provide tissues without fatty-acids and eliminates triglycerides (TG) by the circulation. Mutations in LPL were proven to cause alteration in fractions within lipoprotein, causing the development of atherosclerosis which predispose to weakening coronary artery disease (CAD) and stroke. We examined the linkage between genetic variant HindIII in LPL on lipoprotein fractions, stroke occurrences and CAD. In this case-control study, we have recruited 315 CAD cases and 205 age-matched controls. A total of 520 genomic DNA was digested with the purified PCR products for restriction fragment length polymorphism with HindIII restriction enzyme. The distribution of genotypes in a decreasing order were TT, 148 (47%), GT 135 (42.9%) and GG 32 (10.2%) in CAD groups of the study while the pattern in controls were GT 91 (44.4%), TT 86 (42%) and GG 28 (13.7%). None of all the allele or genotype frequencies were found to be significant in our study (p greater than 0.05), while the biochemical levels for both TG and LDL-c were shown to be prone in CAD patients when compare with the controls. Furthermore, the occurence of strokes were more in CAD groups vs. controls: 72 (22.9%) vs. 7 (3.4%) [p 0.000]. This could indicate the influence of HindIII variant on plasma lipid levels, and the possibility of considering it a risk factor for atherosclerosis leading to CAD and stroke occurrence.