The association between triglyceride-rich lipoproteins, circulating leukocytes, and low-grade inflammation: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

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.

Discordance Between Triglycerides, Remnant Cholesterol and Systemic Inflammation in Patients with Schizophrenia

BACKGROUND/OBJECTIVES

Hypertriglyceridaemia and systemic inflammation are prevalent in patients with schizophrenia and contribute to an increased risk of cardiovascular disease. Although elevated triglycerides (TGs) and remnant cholesterol are linked to inflammation in the general population and individuals with metabolic syndrome, whether they are associated in patients with schizophrenia remains unclear.

METHODS

Fasting levels of TG, cholesterol (total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and remnant cholesterol)), and markers of systemic inflammation including high-sensitivity C-reactive protein (hsCRP), leukocyte counts and their differentials (neutrophils, monocytes and lymphocytes) were determined in 147 patients diagnosed with schizophrenia on long-term antipsychotic regimens and compared with 56 age- and sex-matched healthy controls. Apolipoprotein B and glycosylation of acute phase reactant (GlycA) signatures were assessed by NMR. Circulating cytokine levels were measured by a cytokine/chemokine multiplex assay.

RESULTS

Patients with schizophrenia had markedly elevated TG and remnant cholesterol relative to controls and had evidence of systemic inflammation with increased circulating hsCRP, GlycA, leukocyte, neutrophil counts and neutrophil-to-lymphocyte ratio (NLR). Unexpectedly TG and remnant cholesterol did not correlate with systemic inflammatory markers in patients with schizophrenia, and differences in inflammatory markers between controls and patients persisted after adjusting for the lipid profile. Interleukin (IL)-10 levels were increased in patients with schizophrenia, suggesting an anti-inflammatory signature.

CONCLUSIONS

The discordance between TG, remnant cholesterol and systemic inflammation in patients with schizophrenia suggests these are likely independent contributors to cardiovascular risk in this population.

Lipid-lowering drugs, circulating inflammatory factors, and atrial fibrillation: a mediation Mendelian randomization study

Background

Previous studies have shown an association between lipid-lowering drugs, circulating inflammatory factors, and atrial fibrillation (AF), but the specific effects of lipid-lowering drugs on AF and whether they can be mediated by circulating inflammatory factors remain unclear.

Methods

We collected 10 genetic variants encoding lipid-lowering drug targets (LDLR, HMGCR, PCSK9, NPC1L1, APOB, APOB, ABCG5, ABCG8, LPL, APOC3, and PPARA) and AF based on genome-wide association study (GWAS) summary statistics. Drug target Mendelian randomization (MR) was used to explore the causal relationship between lipid-lowering drugs and AF. In addition, we performed a mediation analysis of 91 circulating inflammatory factors to explore potential mediators. Sensitivity analyses were performed to verify the reliability of the MR Results by MR-Egger intercept test, Cochran's Q test and leave-one-out test.

Results

The results of IVW method showed that LPL agonist had a protective effect on AF(OR = 0. 854, 95%CI: 0.816-0.894, P = 1.844E-11). However, the other nine lipid-lowering drug targets had no significant effect on AF. Notably, we found a mediator role of Fibroblast Growth Factor 5 (FGF5) in the protective effect of LPL agonist on AF with a mediator ratio of 9.22%. Sensitivity analyses supported the robustness of our findings, indicating a possible mediating pathway by which LPL agonists affect the risk of AF.

Conclusion

Our study provides new insights into the complex interactions among lipid-lowering agents, circulating inflammatory factors and AF, and also identified a potential mediating role of FGF5 in the pathogenesis of AF. Our findings highlight the potential of LPL agonists and targeting specific inflammatory factors for therapeutic intervention in AF, providing promising avenues for future research and clinical strategies for the management and prevention of AF.

GlycA Levels Independently Predict Coronary Artery Calcium Incidence and Progression in the ELSA-Brasil Cohort (Brazilian Longitudinal Study of Adult Health)

Atherosclerosis is an inflammatory disease. Coronary artery calcium (CAC) is a marker of atherosclerotic disease events and mortality risk. Increased GlycA, an emerging marker of inflammation, is associated with a higher risk for coronary artery disease (CAD). However, there is conflicting evidence on whether GlycA predicts subclinical CAD progression. We hypothesized that GlycA can predict subclinical CAC incidence/progression in healthy participants. We included 2,690 ELSA-Brasil cohort participants without cardiovascular/chronic inflammatory disease not receiving statin therapy who had GlycA levels measured and 2 interval CAC assessments between 2010 and 2018. Multivariable logistic and linear regression models were computed to evaluate GlycA as a predictor of CAC incidence and progression. CAC incidence required a baseline CAC of 0. CAC progression required a baseline CAC >0. The mean age of participants was 48.6 ± 7.7 years, 56.7% were women, and 54.6% and 16.1% (429 of 2,690) were White and Black, respectively. The mean CAC interscan period was 5.1 ± 0.9 years, the mean GlycA level was 414.7 ± 65 μmol/L, and the incidence of CAC was 13.1% (280 of 2,129). The GlycA level odds ratio for CAC incidence was 1.002 (95% confidence interval 1.0005 to 1.005, p = 0.016), adjusted for demographics, lifestyle, a family history of early CAD (≤60 years), lipids, and co-morbidities. The GlycA (≤p25 vs ≥p75) odds ratio for CAC progression (Berry definition) was 1.77 (95% confidence interval 1.07 to 2.96, p = 0.03) in a similar multivariable-adjusted model. Higher GlycA levels were associated with CAC incidence and progression in a healthy Brazilian cohort.

Lipidomics of triglyceride-rich lipoproteins derived from hyperlipidemic patients on inflammation

BACKGROUND AND AIM

Triglyceride-rich lipoproteins (TRLs) can have an important role in atherosclerosis development due to their size and ability to penetrate the endothelium. While high plasma triglyceride (TG) levels and chronic inflammation are relevant in metabolic diseases, it remains unclear whether TGs are atherogenic or which TRL-TG-derived metabolites are responsible for inflammation. Here, we aimed to study the lipidome modifications of TRL particles enriched in TG in patients with hyperlipidemia and their associations with a proinflammatory status both in vivo and in vitro.

METHODS

Using proton nuclear magnetic resonance (1 H-NMR), we analysed the plasma levels of glycoprotein acetyls and the TRL lipidomic profile of 307 patients with dyslipidemia. THP-1-derived macrophages were used as an in vitro model to explore the molecular inflammatory effects mediated by TRL.

RESULTS

In vivo, higher TRL-TG levels were associated with higher circulating levels of NMR-measured glycoproteins (Glyc-A, Glyc-B and Glyc-F; p < .001). Lipidomic analysis showed that TRL-TG enrichment led to decreased cholesterol and phospholipid content (p < .01), an increase in omega-9, and a decrease in saturated fatty acids (p < .001). THP-1 macrophages exposed to increasing TRL particle concentrations augmented the secretion of IL-1β and TNF-α, which varied based on particle composition. Particles with higher cholesterol and phospholipid contents exerted higher cytokine secretion. The activation of MAPK, Akt/NFκB, and caspase-1 was concurrent with this proinflammatory response.

CONCLUSIONS

High TRL-TG levels are associated with a higher systemic inflammatory status and increased particle concentrations. In vitro, higher particle numbers increase proinflammatory cytokine secretion, with cholesterol and phospholipid-rich TRL being more proinflammatory.

Remnant cholesterol and low-grade inflammation jointly in atherosclerotic cardiovascular disease: implications for clinical trials

PURPOSE OF REVIEW

Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of death despite the development of effective treatments. Recently, elevated remnant cholesterol and low-grade inflammation have emerged as factors explaining part of the residual ASCVD risk. Interestingly, the coexistence of both high remnant cholesterol and low-grade inflammation can further increase the risk of ASCVD. The aim of this review is to describe the role of elevated remnant cholesterol and low-grade inflammation, separately and combined, in ASCVD.

RECENT FINDINGS

Results from recently published studies, including observational and genetic Mendelian randomization studies, support a causal relationship between elevated remnant cholesterol and low-grade inflammation on risk of ASCVD in both primary and secondary prevention settings. In addition, current evidence from observational studies suggests that the coexistence of elevated remnant cholesterol and low-grade inflammation further increases the risk of ASCVD.

SUMMARY

Recent observational studies suggest that high remnant cholesterol combined with low-grade inflammation may confer a particular high risk for ASCVD. Attention on the dual threat from high remnant cholesterol and low-grade inflammation is necessary, and further research in this field is warranted. The effect of remnant cholesterol-lowering drugs and anti-inflammatory drugs on ASCVD risk alone and combined remains to be elucidated.

VIDEO ABSTRACT

http://links.lww.com/COCN/A20.