Apolipoprotein B: a clinically important apolipoprotein which assembles atherogenic lipoproteins and promotes the development of atherosclerosis

Apolipoprotein B100 acts as a tumor suppressor in ovarian cancer via lipid/ER stress axis-induced blockade of autophagy

Ovarian cancer presents a significant treatment challenge due to its insidious nature and high malignancy. As autophagy is a vital cellular process for maintaining homeostasis, targeting the autophagic pathway has emerged as an avenue for cancer therapy. In the present study, we identify apolipoprotein B100 (ApoB100), a key modulator of lipid metabolism, as a potential prognostic biomarker of ovarian cancer. ApoB100 functioned as a tumor suppressor in ovarian cancer, and the knockdown of ApoB100 promoted ovarian cancer progression in vivo. Moreover, ApoB100 blocked autophagic flux, which was dependent on interfering with the lipid accumulation/endoplasmic reticulum (ER) stress axis. The effects of LFG-500, a novel synthetic flavonoid, on ApoB100 induction were confirmed using proteomics and lipidomics analyses. Herein, LFG-500 induced lipid accumulation and ER stress and subsequently blocked autophagy by upregulating ApoB100. Moreover, data from in vivo experiments further demonstrated that ApoB100, as well as the induction of the lipid/ER stress axis and subsequent blockade of autophagy, were responsible for the anti-tumor effects of LFG-500 on ovarian cancer. Hence, our findings support that ApoB100 is a feasible target of ovarian cancer associated with lipid-regulated autophagy and provide evidence for using LFG-500 for ovarian cancer treatment.

Relevance of Lipoprotein Composition in Endothelial Dysfunction and the Development of Hypertension

Endothelial dysfunction and chronic inflammation are determining factors in the development and progression of chronic degenerative diseases, such as hypertension and atherosclerosis. Among the shared pathophysiological characteristics of these two diseases is a metabolic disorder of lipids and lipoproteins. Therefore, the contents and quality of the lipids and proteins of lipoproteins become the targets of therapeutic objective. One of the stages of lipoprotein formation occurs through the incorporation of dietary lipids by enterocytes into the chylomicrons. Consequently, the composition, structure, and especially the properties of lipoproteins could be modified through the intake of bioactive compounds. The objective of this review is to describe the roles of the different lipid and protein components of lipoproteins and their receptors in endothelial dysfunction and the development of hypertension. In addition, we review the use of some non-pharmacological treatments that could improve endothelial function and/or prevent endothelial damage. The reviewed information contributes to the understanding of lipoproteins as vehicles of regulatory factors involved in the modulation of inflammatory and hemostatic processes, the attenuation of oxidative stress, and the neutralization of toxins, rather than only cholesterol and phospholipid transporters. For this review, a bibliographic search was carried out in different online metabases.

Advanced biomolecular spectroscopic profiling of cardiovascular disease macromolecular markers: SIL-6, IL-9, LpA, ApoB, PCSK9 and NT-ProBNP for rapid in-situ detection and monitoring

Cardiovascular disease (CVD) remains a major global health concern and a leading cause of morbidity and mortality worldwide. Early-diagnosis and prompt medical attention are crucial in managing and reducing overall impact on health-and-wellbeing, necessitating the development of innovative diagnostics, which transcend traditional methodologies. Raman spectroscopy uniquely provides molecular fingerprinting and structural information, offering insights into biochemical composition. Integration of Raman spectroscopy with advanced machine learning is established as a powerful clinical adjunct for point-of-care detection of CVDs. A non-invasive, label-free spectroscopic platform coupled with neural network algorithm, 'SKiNET' has been developed to accurately detect the biomolecular changes within plasma of CVD versus healthy cohorts, enabling rapid diagnosis and longer-term monitoring, where the real-time capabilities provide dynamic assessment of progression, aligning treatment strategies with evolving states. CVD has been detected and classified via SKiNET with 88.6 %-accuracy, 92.9 %-specificity and 85.1 %-sensitivity and with 83.8 %-accuracy. The hybrid RS-SKiNET bio-molecularly specific detection signposted a comprehensive panel of CVD-indicative biomarkers, including SIL-6, IL-9, LpA, ApoB, PCSK9 and NT-ProBNP, offering important insights into disease mechanisms and risk-stratification. This multidimensional technique holds potential for improved patient-and-healthcare management for CVDs, laying the platform toward high-throughput biomolecular profiling of CVD-indicative macromolecular biomarkers, particularly vital for widespread point-of-care diagnostics and monitoring.

ERICH4 is not involved in the assembly and secretion of intestinal lipoproteins

BACKGROUND AND AIMS

The small intestine plays a central role in lipid metabolism, most notably the uptake of dietary fats that are packaged into chylomicrons and secreted into the circulation for utilisation by peripheral tissues. While microsomal triglyceride transfer protein (MTP) is known to play a key role in this pathway, the intracellular assembly, trafficking, and secretion of chylomicrons is incompletely understood.

METHODS AND RESULTS

Using human transcriptome datasets to find genes co-regulated with MTTP, we identified ERICH4 as a top hit. The gene encodes for glutamate-rich protein 4, a protein of unknown function. REACTOME gene-function prediction tools indicated that ERICH4 is involved in intestinal lipid metabolism. In addition, GWAS data point to a strong relationship between ERICH4 and plasma lipids. To validate ERICH4 as a lipid gene, we generated whole-body Erich4 knockout (Erich4-/-) mice. ERICH4 deficiency, however, did not result in changes in body weight and composition, food intake, circulating plasma lipids, energy absorption and excretion, and tissue weights compared to controls. Additionally, there were no morphological abnormalities seen in the small intestine. Challenging mice with a high-fat diet did not give rise to a phenotype either.

CONCLUSIONS

Despite prediction tools indicating ERICH4 as a strong candidate gene in intestinal lipid metabolism, we here show that ERICH4 does not play a role in intestinal lipid metabolism in mice. It remains to be established whether ERICH4 plays a role in human lipid metabolism.

Point-based risk score for the risk stratification and prediction of hepatocellular carcinoma: a population-based random survival forest modeling study

Background

The precise associations between common clinical biomarkers and hepatocellular carcinoma (HCC) risk remain unclear but hold valuable insights for HCC risk stratification and prediction.

Methods

We examined the linear and nonlinear associations between the baseline levels of 32 circulating biomarkers and HCC risk in the England cohort of UK Biobank (UKBB) (n = 397,702). The participants were enrolled between 2006 and 2010 and followed up to 31st October 2022. The primary outcome is incident HCC cases. We then employed random survival forests (RSF) to select the top ten most informative biomarkers, considering their association with HCC, and developed a point-based risk score to predict HCC. The performance of the risk score was evaluated in three validation sets including UKBB Scotland and Wales cohort (n = 52,721), UKBB non-White-British cohort (n = 29,315), and the Taizhou Longitudinal Study in China (n = 17,269).

Findings

Twenty-five biomarkers were significantly associated with HCC risk, either linearly or nonlinearly. Based on the RSF model selected biomarkers, our point-based risk score showed a concordance index of 0.866 in the England cohort and varied between 0.814 and 0.849 in the three validation sets. HCC incidence rates ranged from 0.95 to 30.82 per 100,000 from the lowest to the highest quintiles of the risk score in the England cohort. Individuals in the highest risk quintile had a 32-73 times greater risk of HCC compared to those in the lowest quintile. Moreover, over 70% of HCC cases were detected in individuals within the top risk score quintile across all cohorts.

Interpretation

Our simple risk score enables the identification of high-risk individuals of HCC in the general population. However, including some biomarkers, such as insulin-like growth factor 1, not routinely measured in clinical practice may increase the model's complexity, highlighting the need for more accessible biomarkers that can maintain or improve the predictive accuracy of the risk score.

Funding

This work was supported by the National Natural Science Foundation of China (grant numbers: 82204125) and the Science and Technology Support Program of Taizhou (TS202224).

APOB and CCL17 as mediators in the protective effect of SGLT2 inhibition against myocardial infarction: Insights from proteome-wide mendelian randomization

AIMS

Sodium-glucose cotransporter 2 (SGLT2) inhibitors offer a novel therapeutic avenue for myocardial infarction (MI). However, the exact nature of this relationship and the underlying mechanisms are not fully understood.

METHODS

Utilizing a two-sample Mendelian Randomization (MR) analysis, we elucidated the causal effects stemming from the inhibition of SGLT2 on MI. Then, The pool of 4907 circulating proteins within the plasma proteome were utilized to explore the mediators of SGLT2 inhibitors on MI. Protein-protein network and enrichment analysis were conducted to clarify the potential mechanism. Finally, employing MR analysis and meta-analysis techniques, we systematically assessed the causal associations between SGLT2 inhibition and coronary heart diseases (CHD).

RESULTS

SGLT2 inhibition (per 1 SD decrement in HbA1c) was associated with reduced risk of MI (odds ratio [OR] = 0.462, [95% CI 0.222, 0.958], P = 0.038). Among 4907 circulating proteins, we identified APOB and CCL17 which were related to both SGLT2 inhibition and MI. Mediation analysis showed evidence of the indirect effect of SGLT2 inhibition on MI through APOB (β = -0.557, 95%CI [-1.098, -0.155]) with a mediated proportion of 72%, and CCL17 (β = -0.176, 95%CI [-0.332, -0.056]) with a mediated proportion of 17%. The meta-analysis result showed that SGLT2 inhibition was associated with a lower risk of CHD.

CONCLUSION

Based on proteome-wide mendelian randomization, APOB and CCL17 were seen as mediators in the protective effect of SGLT2 inhibition against myocardial infarction.

Biosynthesis and Metabolism of ApoB-Containing Lipoproteins

Recent advances in human genetics, together with a substantial body of epidemiological, preclinical and clinical trial evidence, strongly support a causal relationship between triglyceride-rich lipoproteins (TRLs) and atherosclerotic cardiovascular disease. Consequently, the secretion and metabolism of TRLs have a significant impact on cardiovascular health. This knowledge underscores the importance of understanding the molecular mechanisms and regulation of very-low-density lipoprotein (VLDL) and chylomicron biogenesis. Fortunately, there has been a resurgence of interest in the intracellular assembly, trafficking, degradation, and secretion of VLDL, leading to many ground-breaking molecular insights. Furthermore, the identification of molecular control mechanisms related to triglyceride metabolism has greatly advanced our understanding of the complex metabolism of TRLs. In this review, we explore recent advances in the assembly, secretion, and metabolism of TRLs. We also discuss available treatment strategies for hypertriglyceridemia.

The association of the apolipoprotein B/A1 ratio and the metabolic syndrome in children and adolescents: a systematic review and meta-analysis

Objectives

Metabolic syndrome (MetS) is a constellation of coexisting cardiovascular risk factors. This study aimed to assess the evidence for the association between the apolipoprotein B/A1 ratio, apolipoprotein B, and apolipoprotein A1, and the MetS in children and adolescents.

Methods

The English electronic databases including PubMed, Embase, Web of Science, and Scopus were searched up to February 28, 2022. To ascertain the validity of eligible studies, modified JBI scale was used. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were pooled using the random-effects model to evaluate the association between the apolipoprotein B/A1 ratio, apolipoprotein B, and apolipoprotein A1 and the MetS. Heterogeneity amongst the studies was determined by the use of the Galbraith diagram, Cochran's Q-test, and I2 test. Publication bias was assessed using Egger's and Begg's tests.

Results

From 7356 records, 5 studies were included in the meta-analysis, representing a total number of 232 participants with MetS and 1320 participants as control group. The results indicated that increased levels of apolipoprotein B/A1 ratio (SMD 1.26; 95% CI: 1.04, 1.47) and apolipoprotein B (SMD 0.75; 95% CI: 0.36, 1.14) and decreased levels of apolipoprotein A1 (SMD -0.53; 95% CI: -0.69, -0.37) are linked to the presence of MetS. The notable findings were, children and adolescents with MetS had elevated levels of the apolipoprotein B/A1 ratio, apolipoprotein B, and decreased levels of apolipoprotein A1.

Conclusions

Our results suggest the need to evaluate the levels of apolipoproteins for detecting the risk of MetS in children and adolescents.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-023-01235-z.

Triglyceride-rich lipoproteins and cardiovascular diseases

The global prevalence of cardiovascular diseases (CVD) continues to rise steadily, making it a leading cause of mortality worldwide. Atherosclerosis (AS) serves as a primary driver of these conditions, commencing silently at an early age and culminating in adverse cardiovascular events that severely impact patients' quality of life or lead to fatality. Dyslipidemia, particularly elevated levels of low-density lipoprotein cholesterol (LDL-C), plays a pivotal role in AS pathogenesis as an independent risk factor. Research indicates that abnormal LDL-C accumulation within arterial walls acts as a crucial trigger for atherosclerotic plaque formation. As the disease progresses, plaque accumulation may rupture or dislodge, resulting in thrombus formation and complete blood supply obstruction, ultimately causing myocardial infarction, cerebral infarction, and other common adverse cardiovascular events. Despite adequate pharmacologic therapy targeting LDL-C reduction, patients with cardiometabolic abnormalities remain at high risk for disease recurrence, highlighting the importance of addressing lipid risk factors beyond LDL-C. Recent attention has focused on the causal relationship between triglycerides, triglyceride-rich lipoproteins (TRLs), and their remnants in AS risk. Genetic, epidemiologic, and clinical studies suggest a causal relationship between TRLs and their remnants and the increased risk of AS, and this dyslipidemia may be an independent risk factor for adverse cardiovascular events. Particularly in patients with obesity, metabolic syndrome, diabetes, and chronic kidney disease, disordered TRLs and its remnants levels significantly increase the risk of atherosclerosis and cardiovascular disease development. Accumulation of over-synthesized TRLs in plasma, impaired function of enzymes involved in TRLs lipolysis, and impaired hepatic clearance of cholesterol-rich TRLs remnants can lead to arterial deposition of TRLs and its remnants, promoting foam cell formation and arterial wall inflammation. Therefore, understanding the pathogenesis of TRLs-induced AS and targeting it therapeutically could slow or impede AS progression, thereby reducing cardiovascular disease morbidity and mortality, particularly coronary atherosclerotic heart disease.

The CD36 scavenger receptor Bez regulates lipid redistribution from fat body to ovaries in Drosophila

Lipid distribution in an organism is mediated by the interplay between lipoprotein particles, lipoprotein receptors and class B scavenger receptors of the CD36 family. CD36 is a multifunctional protein mediating lipid uptake, mobilization and signaling at the plasma membrane and inside of the cell. The CD36 protein family has 14 members in Drosophila melanogaster, which allows for the differentiated analysis of their functions. Here, we unravel a role for the so far uncharacterized scavenger receptor Bez in lipid export from Drosophila adipocytes. Bez shares the lipid binding residue with CD36 and is expressed at the plasma membrane of the embryonic, larval and adult fat body. Bez loss of function lowers the organismal availability of storage lipids and blocks the maturation of egg chambers in ovaries. We demonstrate that Bez interacts with the APOB homolog Lipophorin at the plasma membrane of adipocytes and trace the Bez-dependent transfer of an alkyne-labeled fatty acid from adipocytes to Lipophorin. Our study demonstrates how lipids are distributed by scavenger receptor-lipoprotein interplay and contribute to the metabolic control of development.

Targeting the vivid facets of apolipoproteins as a cardiovascular risk factor in rheumatoid arthritis

Mostly, cardiovascular diseases are blamed for casualties in rheumatoid arthritis (RA) patients. Customarily, dyslipidemia is probably the most prevalent underlying cause of untimely demise in people suffering from RA as it hastens the expansion of atherosclerosis. The engagement of inflammatory cytokines like tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), etc., is crucial in the progression and proliferation of both RA and abnormal lipid parameters. Thus, lipid abnormalities should be monitored frequently in patients with both primary and advanced RA stages. An advanced lipid profile examination, i.e., direct role of apolipoproteins associated with various lipid molecules is a more dependable approach for better understanding of the disease and selecting suitable therapeutic targets. Therefore, studying their apolipoproteins is more relevant than assessing RA patients' altered lipid profile levels. Among the various apolipoprotein classes, Apo A1 and Apo B are primarily being focused. In addition, it also addresses how calculating Apo B:Apo A1 ratio can aid in analyzing the disease's risk. The marketed therapies available to control lipid abnormalities are associated with many other risk factors. Hence, directly targeting Apo A1 and Apo B would provide a better and safer option.

Establishing Apolipoprotein-B and non-high-density-lipoprotein-C goals in Indian population: A Cross-sectional study

BACKGROUND

Defining lipid goals solely on low-density lipoprotein-cholesterol (LDL-C) levels in Indian population may cause misclassification due to high prevalence of hypertriglyceridemia and small dense LDL-C particles. International guidelines now recommend Apoliporotein-B (Apo-B) and non-high-density lipoprotein-cholesterol (non-HDL-C) levels as alternative targets. In this study, we used a cross-sectional representative population database to determine Apo-B and non-HDL-C cut-offs corresponding to identified LDL-C targets and compared them to international guidelines.

METHODS

A community-based survey carried out in urban Delhi and adjacent rural Ballabhgarh provided lipid values for 3047 individuals. The Spearman correlation coefficient was used to evaluate the degree of relationship between Apo-B and LDL-C and non-HDL-C. Cut-off values for Apo-B and non-HDL-C were established using receiver operator curve analysis correlating with guideline-recommended LDL-C targets.

RESULTS

Spearman's rank correlations between Apo-B and LDL-C (0.82) and non-HDL-C and LDL-C (0.93) were significant (p < 0.05). Proposed corresponding cut-off values for LDL-C of 55, 70,100,130 and 160 mg/dl for Apo-B and non-HDL-C in our population were 75.3, 75.5, 91.3, 107.6, 119.4 mg/dL and 92.5,96.5, 123.5, 154.5, 179.5 mg/dL respectively. However, in those with triglycerides >150 mg/dl the corresponding Apo-B and non-HDL-C values were 85.1, 92.7, 103.5, 117.5 and 135 mg/dL and 124.5, 126.5, 147.5, 167.5 and 190.5 mg/L respectively.

CONCLUSION

Based on this study we provide Apo-B and non-HDL cut-offs corresponding to target LDL-C values in Indian patients with and without high triglycerides. It is noted that in individuals with triglycerides ≥ 150 mg/dl, the Apo-B levels are much higher than the values recommended by guidelines.

Zebrafish cobll1a regulates lipid homeostasis via the RA signaling pathway

Background

The COBLL1 gene has been implicated in human central obesity, fasting insulin levels, type 2 diabetes, and blood lipid profiles. However, its molecular mechanisms remain largely unexplored.

Methods

In this study, we established cobll1a mutant lines using the CRISPR/Cas9-mediated gene knockout technique. To further dissect the molecular underpinnings of cobll1a during early development, transcriptome sequencing and bioinformatics analysis was employed.

Results

Our study showed that compared to the control, cobll1a -/- zebrafish embryos exhibited impaired development of digestive organs, including the liver, intestine, and pancreas, at 4 days post-fertilization (dpf). Transcriptome sequencing and bioinformatics analysis results showed that in cobll1a knockout group, the expression level of genes in the Retinoic Acid (RA) signaling pathway was affected, and the expression level of lipid metabolism-related genes (fasn, scd, elovl2, elovl6, dgat1a, srebf1 and srebf2) were significantly changed (p < 0.01), leading to increased lipid synthesis and decreased lipid catabolism. The expression level of apolipoprotein genes (apoa1a, apoa1b, apoa2, apoa4a, apoa4b, and apoea) genes were downregulated.

Conclusion

Our study suggest that the loss of cobll1a resulted in disrupted RA metabolism, reduced lipoprotein expression, and abnormal lipid transport, therefore contributing to lipid accumulation and deleterious effects on early liver development.

Exploring apolipoprotein C-III: pathophysiological and pharmacological relevance

The availability of pharmacological approaches able to effectively reduce circulating LDL cholesterol (LDL-C) has led to a substantial reduction in the risk of atherosclerosis-related cardiovascular disease (CVD). However, a residual cardiovascular (CV) risk persists in treated individuals with optimal levels of LDL-C. Additional risk factors beyond LDL-C are involved, and among these, elevated levels of triglycerides (TGs) and TG-rich lipoproteins are causally associated with an increased CV risk. Apolipoprotein C-III (apoC-III) is a key regulator of TG metabolism and hence circulating levels through several mechanisms including the inhibition of lipoprotein lipase activity and alterations in the affinity of apoC-III-containing lipoproteins for both the hepatic receptors involved in their removal and extracellular matrix in the arterial wall. Genetic studies have clarified the role of apoC-III in humans, establishing a causal link with CVD and showing that loss-of-function mutations in the APOC3 gene are associated with reduced TG levels and reduced risk of coronary heart disease. Currently available hypolipidaemic drugs can reduce TG levels, although to a limited extent. Substantial reductions in TG levels can be obtained with new drugs that target specifically apoC-III; these include two antisense oligonucleotides, one small interfering RNA and an antibody.

The Relationship between Complements and Age-Related Macular Degeneration and Its Pathogenesis

Age-related macular degeneration is a retinal disease that causes permanent loss of central vision in people over the age of 65. Its pathogenesis may be related to mitochondrial dysfunction, inflammation, apoptosis, autophagy, complement, intestinal flora, and lipid disorders. In addition, the patient's genes, age, gender, cardiovascular disease, unhealthy diet, and living habits may also be risk factors for this disease. Complement proteins are widely distributed in serum and tissue fluid. In the early 21st century, a connection was found between the complement cascade and age-related macular degeneration. However, little is known about the effect of complement factors on the pathogenesis of age-related macular degeneration. This article reviews the factors associated with age-related macular degeneration, the relationship between each factor and complement, the related functions, and variants and provides new ideas for the treatment of this disease.

The Role of Triglycerides in Atherosclerosis: Recent Pathophysiologic Insights and Therapeutic Implications

Triglycerides have long been recognized as a cardiovascular disease risk factor. However, their precise role in atherosclerosis and potential utility as a therapeutic target remains debated topics. This review aims to shed light on these aspects by exploring the complex relationship between triglycerides and atherosclerosis from pathophysiological and pharmacological perspectives. Triglycerides, primarily carried by chylomicrons and very low-density lipoproteins, play an essential role in energy storage and utilization. Dysregulation of triglyceride homeostasis and triglyceride- rich lipoproteins metabolism often leads to hypertriglyceridemia and subsequently increases atherosclerosis risk. Triglyceride-rich lipoproteins remnants interact with arterial wall endothelial cells, get retained in the subendothelial space, and elicit inflammatory responses, thereby accelerating atherogenesis. Despite the clear association between high triglyceride levels and increased cardiovascular disease risk, intervention trials targeting triglyceride reduction have produced mixed results. We discuss a range of triglyceride-lowering agents, from fibrates to omega-3 fatty acids, with a focus on their mechanism of action, efficacy, and major clinical trial outcomes. Notably, the role of newer agents, such as angiopoietin-like protein 3 and apolipoprotein C3 inhibitors, is also explored. We highlight the challenges and controversies, including the ongoing debate on the causal role of triglyceride in atherosclerosis and the discordant outcomes of recent clinical trials. The potential confounding effects of associated risk factors, such as elevated apolipoprotein B, insulin resistance, and metabolic syndrome, are considered. In conclusion, this review underscores the importance of a nuanced approach to understanding the role of triglycerides in atherosclerosis and their potential as a therapeutic target. Further research is needed to unravel the complex interplay between triglycerides, triglyceride-rich lipoproteins, and associated factors in atherosclerosis pathogenesis and refine triglyceride-targeted therapeutic strategies.

The Soret coefficient of human low-density lipoprotein in solution: a thermophilic behavior

Thermodiffusion, or Soret effect, is the physical phenomenon of matter gradients originated by the migration of chemical species induced by thermal gradients. Thermodiffusion has been widely applied in the study of colloidal suspensions. In this study, we investigate the termodiffusion behavior of low-density lipoprotein (LDL) particles, by the Soret coefficient measurement. It is a new approach to studies of plasma lipoproteins. The experimental work was based on thermal- and Soret-lens effects. These effects were induced by laser irradiation of the samples, at two different time scales, in a Z-scan setup. LDL samples were analyzed under physiological conditions, notedly, ionic strength and pH, and at different temperatures. Temperature dependence of Soret coefficient showed a slight decrease in the absolute value of this coefficient, as a function of temperature increasing. However, its sign does not change at the temperatures investigated (15, 22.5 and 37.5 °C). The results show that LDL particles exhibit thermophilic behavior. The origin of this thermophilic behavior is not yet completely understood. We discuss some aspects that can be related with the Soret effect in LDL samples.

Cumulative remnant cholesterol predicts cardiovascular outcomes in elderly patients with atherosclerotic cardiovascular disease

AIMS

Remnant cholesterol (RC) reportedly mediates residual cardiovascular risk in atherosclerotic cardiovascular diseases (ASCVD). However, few studies have characterized long-term cumulative RC exposure among elderly people. The study aimed to evaluate the association between cumulative exposure to RC and incident major adverse cardiovascular events (MACE) by analysing a cohort of elderly patients with ASCVD.

METHODS AND RESULTS

This retrospective multicentre cohort study enrolled ASCVD participants aged ≥75 years with baseline visits occurring from 2006 to 2012 followed by four in-person visits. Cumulative RC was estimated as the area under the curve using measurements from the first to fourth visits by using 9-year data. The time-weighted average (TWA) RC was expressed as cumulative exposure to RC averaged by years. All outcomes were follow-up from the fourth visit to the year 2021. Outcomes included a composite of MACE (stroke, unstable angina pectoris, myocardial infarction, and cardiac death). We included 4,680 participants (73.1% male, mean age 79.3 ± 2.5 years). The median follow-up duration was 6.1 years (interquartile range: 3.4-6.6 years). In the multivariable model adjusted for traditional cardiovascular risk factors, low-density lipoprotein cholesterol level, and most recent RC level, the hazard ratios for MACE that compared the high and low tertiles of the RC variables were 1.30 [95% confidence interval (CI), 1.16-1.44] for cumulative RC and 1.36 (95% CI, 1.23-1.52) for TWA RC. Consistent significant associations were observed among most propensity score analyses.

CONCLUSIONS

Long-term cumulative RC was independently associated with incident MACE in elderly participants with ASCVD, suggesting that achieving and maintaining optimal RC levels later in life may still improve cardiovascular outcomes.

Inclisiran and cardiovascular events: a comprehensive review of efficacy, safety, and future perspectives

PURPOSE OF REVIEW

This review aims to offer an up-to-date evaluation of Inclisiran's (a small interfering RNA treatment) ability to decrease low-density lipoprotein cholesterol (LDL-C), as well as its safety and potential effects on decreasing cardiovascular risk.

RECENT FINDINGS

Inclisiran significantly lowers LDL-C levels, as shown by phase III studies, by inhibiting hepatic synthesis of proprotein convertase subtilisin kexin 9 (PCSK-9), a protein implicated in the degradation of LDL receptors. Inclisiran has the benefit of subcutaneous injection twice a year, which may reduce patient nonadherence when compared with other LDL-C reducing therapies such as statins and ezetimibe, which require daily dosing. When added on top of statins, a greater proportion of patients achieved recommended cholesterol goals. It has also demonstrated a good safety profile with few adverse effects.

SUMMARY

Inclisiran is a promising treatment for lowering LDL-C levels in people at high risk of atherosclerotic cardiovascular disease. It is a practical and well tolerated option for those who struggle to stick to medication regimes because of its twice-yearly dosage schedule and a good safety profile. Although it has been demonstrated to be effective in decreasing LDL-C, further research is needed to determine its impact on reducing cardiovascular events. Nonetheless, Inclisiran is a significant advancement in lipid-lowering medication and could improve patient outcomes.

RNA-Seq analysis of the pyloric caecum, liver, and muscle reveals molecular mechanisms regulating fillet color in rainbow trout

BACKGROUND

The characteristic pink-reddish color in the salmonids fillet is an important, appealing quality trait for consumers and producers. The color results from diet supplementation with carotenoids, which accounts for up to 20-30% of the feed cost. Pigment retention in the muscle is a highly variable phenotype. In this study, we aimed to understand the molecular basis for the variation in fillet color when rainbow trout (Oncorhynchus mykiss) fish families were fed an Astaxanthin-supplemented diet. We used RNA-Seq to study the transcriptome profile in the pyloric caecum, liver, and muscle from fish families with pink-reddish fillet coloration (red) versus those with lighter pale coloration (white).

RESULTS

More DEGs were identified in the muscle (5,148) and liver (3,180) than in the pyloric caecum (272). Genes involved in lipid/carotenoid metabolism and transport, ribosomal activities, mitochondrial functions, and stress homeostasis were uniquely enriched in the muscle and liver. For instance, the two beta carotene genes (BCO1 and BCO2) were significantly under-represented in the muscle of the red fillet group favoring more carotenoid retention. Enriched genes in the pyloric caecum were involved in intestinal absorption and transport of carotenoids and lipids. In addition, the analysis revealed the modulation of several genes with immune functions in the pyloric caecum, liver, and muscle.

CONCLUSION

The results from this study deepen our understanding of carotenoid dynamics in rainbow trout and can guide us on strategies to improve Astaxanthin retention in the rainbow trout fillet.

Novel Biomarkers for Atherosclerotic Disease: Advances in Cardiovascular Risk Assessment

Atherosclerosis is a significant health concern with a growing incidence worldwide. It is directly linked to an increased cardiovascular risk and to major adverse cardiovascular events, such as acute coronary syndromes. In this review, we try to assess the potential diagnostic role of biomarkers in the early identification of patients susceptible to the development of atherosclerosis and other adverse cardiovascular events. We have collected publications concerning already established parameters, such as low-density lipoprotein cholesterol (LDL-C), as well as newer markers, e.g., apolipoprotein B (apoB) and the ratio between apoB and apoA. Additionally, given the inflammatory nature of the development of atherosclerosis, high-sensitivity c-reactive protein (hs-CRP) or interleukin-6 (IL-6) are also discussed. Additionally, newer publications on other emerging components linked to atherosclerosis were considered in the context of patient evaluation. Apart from the already in-use markers (e.g., LDL-C), emerging research highlights the potential of newer molecules in optimizing the diagnosis of atherosclerotic disease in earlier stages. After further studies, they might be fully implemented in the screening protocols.

Association of the triglycerides and glucose index and the homeostatic model assessment of insulin resistance with lipoprotein(a), apolipoprotein AI, and apolipoprotein B concentrations in children with normal-weight

The aim of this study was to compare the association of the triglycerides and glucose (TyG) index and homeostatic model assessment of insulin resistance (HOMA-IR) with lipoprotein(a) (lp[a]), apolipoprotein AI (apoAI), and apoliprotein B (apoB) concentrations in children with normal-weight. Children with normal weight aged 6-10 years and Tanner 1 stage were included in a cross-sectional study. Underweight, overweight, obesity, smoking, alcohol intake, pregnancy, acute or chronic illnesses, and any kind of pharmacological treatment were exclusion criteria. According to the lp(a) levels, children were allocated into the groups with elevated concentrations and normal values. A total of 181 children with normal weight and an average age of 8.4 ± 1.4 years were enrolled in the study. The TyG index showed a positive correlation with lp(a) and apoB in the overall population (r = 0.161 and r = 0.351, respectively) and boys (r = 0.320 and r = 0.401, respectively), but only with apoB in the girls (r = 0.294); while the HOMA-IR had a positive correlation with lp(a) levels in the overall population (r = 0.213) and boys (r = 0.328). The linear regression analysis showed that the TyG index is associated with lp(a) and apoB in the overall population (B = 20.72; 95%CI 2.03-39.41 and B = 27.25; 95%CI 16.51-37.98, respectively) and boys (B = 40.19; 95%CI 14.50-65.7 and B = 29.60; 95%CI 15.03-44.17, respectively), but only with apoB in the girls (B = 24.22; 95%CI 7.90-40.53). The HOMA-IR is associated with lp(a) in the overall population (B = 5.37; 95%CI 1.74-9.00) and boys (B = 9.63; 95%CI 3.65-15.61).   Conclusion: The TyG index is associated with both lp(a) and apoB in children with normal-weight. What is Known: • The triglycerides and glucose index has been positively associated with an increased risk of cardiovascular disease in adults. What is New: • The triglycerides and glucose index is strongly associated with lipoprotein(a) and apolipoprotein B in children with normal-weight. • The triglycerides and glucose index may be a useful tool to identify cardiovascular risk in children with normal-weight.

Calcific aortic valve disease: mechanisms, prevention and treatment

Calcific aortic valve disease (CAVD) is the most common disorder affecting heart valves and is characterized by thickening, fibrosis and mineralization of the aortic valve leaflets. Analyses of surgically explanted aortic valve leaflets have shown that dystrophic mineralization and osteogenic transition of valve interstitial cells co-occur with neovascularization, microhaemorrhage and abnormal production of extracellular matrix. Age and congenital bicuspid aortic valve morphology are important and unalterable risk factors for CAVD, whereas additional risk is conferred by elevated blood pressure and plasma lipoprotein(a) levels and the presence of obesity and diabetes mellitus, which are modifiable factors. Genetic and molecular studies have identified that the NOTCH, WNT-β-catenin and myocardin signalling pathways are involved in the control and commitment of valvular cells to a fibrocalcific lineage. Complex interactions between valve endothelial and interstitial cells and immune cells promote the remodelling of aortic valve leaflets and the development of CAVD. Although no medical therapy is effective for reducing or preventing the progression of CAVD, studies have started to identify actionable targets.

Elevated ApoB/ApoA-Ι ratio is associated with poor outcome in acute ischemic stroke

BACKGROUND

Apolipoproteins are known atherogenic factors that play important roles in many mechanisms related to acute ischemic stroke (AIS). However, it is unclear whether the ApoB/ApoA-Ι ratio is related to the prognosis of patients with AIS.

METHODS

We conducted a prospective cohort study in the Department of Neurology, Yangpu Hospital, School of Medicine, Tongji University and investigated the association between ApoB/ApoA-Ι ratio and poor outcomes at 3 months of AIS.

RESULTS

1,247 patients that met the eligibility criteria were enrolled in our study. We found that ApoA-Ι (Adjusted odds ratios (adjOR) 0.529, 95 %CI 0.327-0.855), ApoB (adjOR 3.015, 95 %CI 1.746-5.207), and ApoB/ApoA-Ι ratio (adjOR 3.986, 95 %CI 2.220-7.155) were independently associated with poor outcomes in acute ischemic stroke. During subgroup analysis, the ApoB/ApoA-Ι ratio was more likely associated with poor AIS outcomes in males and patients younger than 80 with SAO(Small Artery Occlusion) and no history of diabetes or statin use. Restricted cubic spline analyses explored the correlation between poor outcomes and ApoB/ApoA-Ι ratio.

CONCLUSIONS

Higher ApoB, lower ApoA-Ι, and higher ApoB/ApoA-Ι ratios were independently associated with poor outcomes in AIS. However, ApoB and ApoA-Ι were not related to hemorrhagic transformation in AIS.

Mechanism of the Regulation of Plasma Cholesterol Levels by PI(4,5)P2

Elevated low-density lipoprotein (LDL) cholesterol (LDLc) is one of the most well-established risk factors for cardiovascular disease, while high levels of high-density lipoprotein (HDL) cholesterol (HDLc) have been associated with protection from cardiovascular disease. Cardiovascular disease remains one of the leading causes of death worldwide; thus it is important to understand mechanisms that impact LDLc and HDLc metabolism. In this chapter, we will discuss molecular processes by which phosphatidylinositol-(4,5)-bisphosphate, PI(4,5)P₂, is thought to modulate LDLc or HDLc. Section 1 will provide an overview of cholesterol in the circulation, discussing processes that modulate the various forms of lipoproteins (LDL and HDL) carrying cholesterol. Section 2 will describe how a PI(4,5)P₂ phosphatase, transmembrane protein 55B (TMEM55B), impacts circulating LDLc levels through its ability to regulate lysosomal decay of the low-density lipoprotein receptor (LDLR), the primary receptor for hepatic LDL uptake. Section 3 will discuss how PI(4,5)P₂ interacts with apolipoprotein A-I (apoA1), the key apolipoprotein on HDL. In addition to direct mechanisms of PI(4,5)P₂ action on circulating cholesterol, Sect. 4 will review how PI(4,5)P₂ may indirectly impact LDLc and HDLc by affecting insulin action. Last, as cholesterol is controlled through intricate negative feedback loops, Sect. 5 will describe how PI(4,5)P₂ is regulated by cholesterol.

Intake of legumes and cardiovascular disease: A systematic review and dose-response meta-analysis

AIMS

To summarize the evidence on the association between the intake of legumes and the risk of cardiovascular disease (CVD) overall, coronary heart disease (CHD) and stroke, and to identify optimal intake levels for reduced disease risk through a systematic review and dose-response meta-analysis.

DATA SYNTHESIS

We have systematically searched PubMed, Scopus and Web of Science up to March, 2022 for the retrieval of intervention and observational studies (PROSPERO Reg. number: CRD42021247565). Pooled relative risks (RRs) comparing extreme categories of intake were computed using random-effects models. One-stage dose-response meta-analyses were also performed using random-effects models. 22 831 articles were screened resulting in 26 eligible observational studies (21 prospective cohort and 5 case-control studies). When comparing extreme categories of intake, the consumption of legumes was inversely associated with CVD (n = 25: RR = 0.94; 95%CI:0.89,0.99) and CHD (n = 16: RR = 0.90; 95%CI:0.85,0.96), but not with stroke (n = 9: RR = 1.00; 95%CI:0.93,1.08). We further found evidence for an inverse dose-response association with CHD, increasing in magnitude up to an intake of 400 g/week, after which the benefit seems to level-off.

CONCLUSIONS

The intake of legumes was associated with a reduced risk of CVD and CHD, but not with stroke, among individuals with the highest consumption levels. An intake level of 400 g/week seemed to provide the optimal cardiovascular benefit. Further research is needed to better understand the role of legumes in stroke subtypes.

A Review of Current Evidence on the Relationship between Phosphate Metabolism and Metabolic Syndrome

Phosphorus, present as phosphate in biological systems, is an essential mineral for various biological activities and biochemical processes. Numerous studies have indicated that disturbed phosphate balance may contribute to the development of metabolic syndrome (MetS). However, no consistent result was found on the association between phosphorus intake and serum phosphate concentration with MetS. It is believed that both positive and negative impacts of phosphorus/phosphate co-exist in parallel during MetS condition. Reduced phosphate level contributed to the development of obesity and hyperglycaemia. Low phosphate is believed to compromise energy production, reduce exercise capacity, increase food ingestion, and impair glucose metabolism. On the other hand, the effects of phosphorus/phosphate on hypertension are rather complex depending on the source of phosphorus and subjects' health conditions. Phosphorus excess activates sympathetic nervous system, renin-angiotensin-aldosterone system, and induces hormonal changes under pathological conditions, contributing to the blood pressure-rising effects. For lipid metabolism, adequate phosphate content ensures a balanced lipid profile through regulation of fatty acid biosynthesis, oxidation, and bile acid excretion. In conclusion, phosphate metabolism serves as a potential key feature for the development and progression of MetS. Dietary phosphorus and serum phosphate level should be under close monitoring for the management of MetS.

A New Structural Model of Apolipoprotein B100 Based on Computational Modeling and Cross Linking

ApoB-100 is a member of a large lipid transfer protein superfamily and is one of the main apolipoproteins found on low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) particles. Despite its clinical significance for the development of cardiovascular disease, there is limited information on apoB-100 structure. We have developed a novel method based on the “divide and conquer” algorithm, using PSIPRED software, by dividing apoB-100 into five subunits and 11 domains. Models of each domain were prepared using I-TASSER, DEMO, RoseTTAFold, Phyre2, and MODELLER. Subsequently, we used disuccinimidyl sulfoxide (DSSO), a new mass spectrometry cleavable cross-linker, and the known position of disulfide bonds to experimentally validate each model. We obtained 65 unique DSSO cross-links, of which 87.5% were within a 26 Å threshold in the final model. We also evaluated the positions of cysteine residues involved in the eight known disulfide bonds in apoB-100, and each pair was measured within the expected 5.6 Å constraint. Finally, multiple domains were combined by applying constraints based on detected long-range DSSO cross-links to generate five subunits, which were subsequently merged to achieve an uninterrupted architecture for apoB-100 around a lipoprotein particle. Moreover, the dynamics of apoB-100 during particle size transitions was examined by comparing VLDL and LDL computational models and using experimental cross-linking data. In addition, the proposed model of receptor ligand binding of apoB-100 provides new insights into some of its functions.

Long Noncoding RNA lncRHL Regulates Hepatic VLDL Secretion by Modulating hnRNPU/BMAL1/MTTP Axis

Dysregulation of hepatic VLDL secretion contributes to the pathogenesis of metabolic diseases, such as nonalcoholic fatty liver disease (NAFLD) and hyperlipidemia. Accumulating evidence has suggested that long noncoding RNAs (lncRNAs) had malfunctioning roles in the pathogenesis of NAFLD. However, the function of lncRNAs in controlling hepatic VLDL secretion remains largely unillustrated. Here, we identified a novel lncRNA, lncRNA regulator of hyperlipidemia (lncRHL), which was liver-enriched, downregulated on high-fat diet feeding, and inhibited by oleic acid treatment in primary hepatocytes. With genetic manipulation in mice and primary hepatocytes, depletion of lncRHL induces hepatic VLDL secretion accompanied by decreased hepatic lipid contents. Conversely, lncRHL restoration reduces VLDL secretion with increased lipid deposition in hepatocytes. Mechanistic analyses indicate that lncRHL binds directly to heterogeneous nuclear ribonuclear protein U (hnRNPU), and thereby enhances its stability, and that hnRNPU can transcriptional activate Bmal1, leading to inhibition of VLDL secretion in hepatocytes. lncRHL deficiency accelerates the protein degradation of hnRNPU and suppresses the transcription of Bmal1, which in turn activates VLDL secretion in hepatocytes. With results taken together, we conclude that lncRHL is a novel suppressor of hepatic VLDL secretion. Activating the lncRHL/hnRNPU/BMAL1/MTTP axis represents a potential strategy for the maintenance of intrahepatic and plasma lipid homeostasis.

Genetic, epigenetic, and environmental mechanisms govern allele-specific gene expression

Allele-specific expression (ASE) is a phenomenon in which one allele is preferentially expressed over the other. Genetic and epigenetic factors cause ASE by altering the final composition of a gene's product, leading to expression imbalances that can have functional consequences on phenotypes. Environmental signals also impact allele-specific expression, but how they contribute to this cross talk remains understudied. Here, we explored how genotype, parent-of-origin, tissue, sex, and dietary fat simultaneously influence ASE biases. Male and female mice from a F₁ reciprocal cross of the LG/J and SM/J strains were fed a high or low fat diet. We harnessed strain-specific variants to distinguish between two ASE classes: parent-of-origin-dependent (unequal expression based on parental origin) and sequence-dependent (unequal expression based on nucleotide identity). We present a comprehensive map of ASE patterns in 2853 genes across three tissues and nine environmental contexts. We found that both ASE classes are highly dependent on tissue and environmental context. They vary across metabolically relevant tissues, between males and females, and in response to dietary fat. We also found 45 genes with inconsistent ASE biases that switched direction across tissues and/or environments. Finally, we integrated ASE and QTL data from published intercrosses of the LG/J and SM/J strains. Our ASE genes are often enriched in QTLs for metabolic and musculoskeletal traits, highlighting how this orthogonal approach can prioritize candidate genes. Together, our results provide novel insights into how genetic, epigenetic, and environmental mechanisms govern allele-specific expression, which is an essential step toward deciphering the genotype-to-phenotype map.

Patient Stratification in Sepsis: Using Metabolomics to Detect Clinical Phenotypes, Sub-Phenotypes and Therapeutic Response

Infections are common and need minimal treatment; however, occasionally, due to inappropriate immune response, they can develop into a life-threatening condition known as sepsis. Sepsis is a global concern with high morbidity and mortality. There has been little advancement in the treatment of sepsis, outside of antibiotics and supportive measures. Some of the difficulty in identifying novel therapies is the heterogeneity of the condition. Metabolic phenotyping has great potential for gaining understanding of this heterogeneity and how the metabolic fingerprints of patients with sepsis differ based on survival, organ dysfunction, disease severity, type of infection, treatment or causative organism. Moreover, metabolomics offers potential for patient stratification as metabolic profiles obtained from analytical platforms can reflect human individuality and phenotypic variation. This article reviews the most relevant metabolomic studies in sepsis and aims to provide an overview of the metabolic derangements in sepsis and how metabolic phenotyping has been used to identify sub-groups of patients with this condition. Finally, we consider the new avenues that metabolomics could open, exploring novel phenotypes and untangling the heterogeneity of sepsis, by looking at advances made in the field with other -omics technologies.

Metabolism of triglyceride-rich lipoproteins in health and dyslipidaemia

Accumulating evidence points to the causal role of triglyceride-rich lipoproteins and their cholesterol-enriched remnants in atherogenesis. Genetic studies in particular have not only revealed a relationship between plasma triglyceride levels and the risk of atherosclerotic cardiovascular disease, but have also identified key proteins responsible for the regulation of triglyceride transport. Kinetic studies in humans using stable isotope tracers have been especially useful in delineating the function of these proteins and revealing the hitherto unappreciated complexity of triglyceride-rich lipoprotein metabolism. Given that triglyceride is an essential energy source for mammals, triglyceride transport is regulated by numerous mechanisms that balance availability with the energy demands of the body. Ongoing investigations are focused on determining the consequences of dysregulation as a result of either dietary imprudence or genetic variation that increases the risk of atherosclerosis and pancreatitis. The identification of molecular control mechanisms involved in triglyceride metabolism has laid the groundwork for a 'precision-medicine' approach to therapy. Novel pharmacological agents under development have specific molecular targets within a regulatory framework, and their deployment heralds a new era in lipid-lowering-mediated prevention of disease. In this Review, we outline what is known about the dysregulation of triglyceride transport in human hypertriglyceridaemia.

Osteoblasts impair cholesterol synthesis in chondrocytes via Notch1 signalling

Objectives

Previous reports have proposed the importance of signalling and material exchange between cartilage and subchondral bone. However, the specific experimental evidence is still insufficient to support the effect of this interdependent relationship on mutual cell behaviours. In this study, we aimed to investigate cellular lipid metabolism in chondrocytes induced by osteoblasts.

Methods

Osteoblast‐induced chondrocytes were established in a Transwell chamber. A cholesterol detection kit was used to detect cholesterol contents. RNA sequencing and qPCR were performed to assess changes in mRNA expression. Western blot analysis was performed to detect protein expression. Immunofluorescence staining was conducted to show the cellular distribution of proteins.

Results

Cholesterol levels were significantly decreased in chondrocytes induced by osteoblasts. Osteoblasts reduced cholesterol synthesis in chondrocytes by reducing the expression of a series of synthetases, including Fdft1, Sqle, Lss, Cyp51, Msmo1, Nsdhl, Sc5d, Dhcr24 and Dhcr7. This modulatory process involves Notch1 signalling. The expression of ncstn and hey1, an activator and a specific downstream target of Notch signalling, respectively, were decreased in chondrocytes induced by osteoblasts.

Conclusions

For the first time, we elucidated that communication with osteoblasts reduces cholesterol synthesis in chondrocytes through Notch1 signalling. This result may provide a better understanding of the effect of subchondral bone signalling on chondrocytes.

Bioactivity of Dietary Polyphenols: The Role in LDL-C Lowering

Cardiovascular diseases are the leading causes of the death around the world. An elevation of the low-density lipoprotein cholesterol (LDL-C) level is one of the most important risk factors for cardiovascular diseases. To achieve optimal plasma LDL-C levels, clinal therapies were investigated which targeted different metabolism pathways. However, some therapies also caused various adverse effects. Thus, there is a need for new treatment options and/or combination therapies to inhibit the LDL-C level. Dietary polyphenols have received much attention in the prevention of cardiovascular diseases due to their potential LDL-C lowering effects. However, the effectiveness and potential mechanisms of polyphenols in lowering LDL-C is not comprehensively summarized. This review focused on dietary polyphenols that could reduce LDL-C and their mechanisms of action. This review also discussed the limitations and suggestions regarding previous studies.

Metabolism of Triglyceride-Rich Lipoproteins

Triglycerides are critical lipids as they provide an energy source that is both compact and efficient. Due to its hydrophobic nature triglyceride molecules can pack together densely and so be stored in adipose tissue. To be transported in the aqueous medium of plasma, triglycerides have to be incorporated into lipoprotein particles along with other components such as cholesterol, phospholipid and associated structural and regulatory apolipoproteins. Here we discuss the physiology of normal triglyceride metabolism, and how impaired metabolism induces hypertriglyceridemia and its pathogenic consequences including atherosclerosis. We also discuss established and novel therapies to reduce triglyceride-rich lipoproteins.

Apolipoprotein B and Cardiovascular Disease: Biomarker and Potential Therapeutic Target

Apolipoprotein (apo) B, the critical structural protein of the atherogenic lipoproteins, has two major isoforms: apoB48 and apoB100. ApoB48 is found in chylomicrons and chylomicron remnants with one apoB48 molecule per chylomicron particle. Similarly, a single apoB100 molecule is contained per particle of very-low-density lipoprotein (VLDL), intermediate density lipoprotein, LDL and lipoprotein(a). This unique one apoB per particle ratio makes plasma apoB concentration a direct measure of the number of circulating atherogenic lipoproteins. ApoB levels indicate the atherogenic particle concentration independent of the particle cholesterol content, which is variable. While LDL, the major cholesterol-carrying serum lipoprotein, is the primary therapeutic target for management and prevention of atherosclerotic cardiovascular disease, there is strong evidence that apoB is a more accurate indicator of cardiovascular risk than either total cholesterol or LDL cholesterol. This review examines multiple aspects of apoB structure and function, with a focus on the controversy over use of apoB as a therapeutic target in clinical practice. Ongoing coronary artery disease residual risk, despite lipid-lowering treatment, has left patients and clinicians with unsatisfactory options for monitoring cardiovascular health. At the present time, the substitution of apoB for LDL-C in cardiovascular disease prevention guidelines has been deemed unjustified, but discussions continue.

Intestinal and Hepatic Uptake of Dietary Peroxidized Lipids and Their Decomposition Products, and Their Subsequent Effects on Apolipoprotein A1 and Paraoxonase1

Both pro- and antiatherosclerotic effects have been ascribed to dietary peroxidized lipids. Confusion on the role of peroxidized lipids in atherosclerotic cardiovascular disease is punctuated by a lack of understanding regarding the metabolic fate and potential physiological effects of dietary peroxidized lipids and their decomposition products. This study sought to determine the metabolic fate and physiological ramifications of 13-hydroperoxyoctadecadienoic acid (13-HPODE) and 13-HODE (13-hydroxyoctadecadienoic acid) supplementation in intestinal and hepatic cell lines, as well as any effects resulting from 13-HPODE or 13-HODE degradation products. In the presence of Caco-2 cells, 13-HPODE was rapidly reduced to 13-HODE. Upon entering the cell, 13-HODE appears to undergo decomposition, followed by esterification. Moreover, 13-HPODE undergoes autodecomposition to produce aldehydes such as 9-oxononanoic acid (9-ONA). Results indicate that 9-ONA was oxidized to azelaic acid (AzA) rapidly in cell culture media, but AzA was poorly absorbed by intestinal cells and remained detectable in cell culture media for up to 18 h. An increased apolipoprotein A1 (ApoA1) secretion was observed in Caco-2 cells in the presence of 13-HPODE, 9-ONA, and AzA, whereas such induction was not observed in HepG2 cells. However, 13-HPODE treatments suppressed paraoxonase 1 (PON1) activity, suggesting the induction of ApoA1 secretion by 13-HPODE may not represent functional high-density lipoprotein (HDL) capable of reducing oxidative stress. Alternatively, AzA induced both ApoA1 secretion and PON1 activity while suppressing ApoB secretion in differentiated Caco-2 cells but not in HepG2. These results suggest oxidation of 9-ONA to AzA might be an important phenomenon, resulting in the accumulation of potentially beneficial dietary peroxidized lipid-derived aldehydes.

Zebrafish mutants provide insights into Apolipoprotein B functions during embryonic development and pathological conditions

Apolipoprotein B (ApoB) is the primary protein of chylomicrons, VLDLs, and LDLs and is essential for their production. Defects in ApoB synthesis and secretion result in several human diseases, including abetalipoproteinemia and familial hypobetalipoproteinemia (FHBL1). In addition, ApoB-related dyslipidemia is linked to nonalcoholic fatty liver disease (NAFLD), a silent pandemic affecting billions globally. Due to the crucial role of APOB in supplying nutrients to the developing embryo, ApoB deletion in mammals is embryonic lethal. Thus, a clear understanding of the roles of this protein during development is lacking. Here, we established zebrafish mutants for 2 apoB genes: apoBa and apoBb.1. Double-mutant embryos displayed hepatic steatosis, a common hallmark of FHBL1 and NAFLD, as well as abnormal liver laterality, decreased numbers of goblet cells in the gut, and impaired angiogenesis. We further used these mutants to identify the domains within ApoB responsible for its functions. By assessing the ability of different truncated forms of human APOB to rescue the mutant phenotypes, we demonstrate the benefits of this model for prospective therapeutic screens. Overall, these zebrafish models uncover what are likely previously undescribed functions of ApoB in organ development and morphogenesis and shed light on the mechanisms underlying hypolipidemia-related diseases.

High-Resolution Proteomic Profiling Shows Sexual Dimorphism in Zebrafish Heart-Associated Proteins

Understanding the molecular basis of sexual dimorphism in the cardiovascular system may contribute to the improvement of the outcome in biological, pharmacological, and toxicological studies as well as on the development of sex-based drugs and therapeutic approaches. Label-free protein quantification using high-resolution mass spectrometry was applied to detect sex-based proteome differences in the heart of zebrafish Danio rerio. Out of almost 3000 unique identified proteins in the heart, 79 showed significant abundance differences between male and female fish. The functional differences were mapped using enrichment analyses. Our results suggest that a large amount of materials needed for reproduction (e.g., sugars, lipids, proteins, etc.) may impose extra pressure on blood, vessels, and heart on their way toward the ovaries. In the present study, the female's heart shows a clear sexual dimorphism by changing abundance levels of numerous proteins, which could be a way to safely overcome material-induced elevated pressures. These proteins belong to the immune system, oxidative stress response, drug metabolization, detoxification, energy, metabolism, and so on. In conclusion, we showed that sex can induce dimorphism at the molecular level in nonsexual organs such as heart and must be considered as an important factor in cardiovascular research. Data are available via ProteomeXchange with identifier PXD023506.

Discordance Between Apolipoprotein B and Low-Density Lipoprotein Cholesterol and Progression of Coronary Artery Calcification in Middle Age

BACKGROUND

A high level of apolipoprotein B (apoB) is associated with incident coronary artery disease (CAD) when low-density lipoprotein cholesterol (LDL-C) level is discordantly low or concordantly high. However, data on the relationship of apoB with subclinical measure of CAD are limited.

METHODS AND RESULTS

A total of 14,205 men (mean age 41.0 years) who were free of cardiovascular disease at baseline and who underwent a health checkup exam, including measurement of coronary artery calcium (CAC), were studied. Of the study group, 2,773 participants (19.5%) had CAC at baseline, and CAC progression was observed in 2,550 (18.0%). The multivariate-adjusted CAC score ratios (95% confidence interval) comparing discordantly high apoB/low LDL-C and concordantly high apoB/high LDL-C with concordantly low apoB/low LDL-C were 1.51 (0.98-2.32) and 2.70 (2.19-3.33), respectively. The corresponding relative risks for CAC progression were 1.26 (1.02-1.56) and 1.49 (1.34-1.66), respectively. These associations did not change appreciably after adjustment for insulin resistance and subclinical inflammation.

CONCLUSIONS

Discordant analysis showed that a high apoB level was strongly associated with prevalence and progression of CAC independent of LDL-C in a large cohort of healthy adults. The present study results highlighted the importance of an apoB measure as a potential target for primary prevention of coronary atherosclerosis in healthy adults.

In Vitro Liver Toxicity Testing of Chemicals: A Pragmatic Approach

The liver is among the most frequently targeted organs by noxious chemicals of diverse nature. Liver toxicity testing using laboratory animals not only raises serious ethical questions, but is also rather poorly predictive of human safety towards chemicals. Increasing attention is, therefore, being paid to the development of non-animal and human-based testing schemes, which rely to a great extent on in vitro methodology. The present paper proposes a rationalized tiered in vitro testing strategy to detect liver toxicity triggered by chemicals, in which the first tier is focused on assessing general cytotoxicity, while the second tier is aimed at identifying liver-specific toxicity as such. A state-of-the-art overview is provided of the most commonly used in vitro assays that can be used in both tiers. Advantages and disadvantages of each assay as well as overall practical considerations are discussed.

Regulation of Apolipoprotein B by Natural Products and Nutraceuticals: A Comprehensive Review

Cardiovascular Disease (CVD) is the most important and the number one cause of mortality in both developing and industrialized nations. The co-morbidities associated with CVD are observed from infancy to old age. Apolipoprotein B100 (Apo B) is the primary apolipoprotein and structural protein of all major atherogenic particles derived from the liver including Very-Low- Density Lipoproteins (VLDL), Intermediate-density Lipoprotein (IDL), and Low-density Lipoprotein (LDL) particles. It has been suggested that measurement of the Apo B concentration is a superior and more reliable index for the prediction of CVD risk than is the measurement of LDL-C. Nutraceuticals and medicinal plants have attracted significant attention as it pertains to the treatment of non-communicable diseases, particularly CVD, diabetes mellitus, hypertension, and Nonalcoholic Fatty Liver Disease (NAFLD). The effect of nutraceuticals and herbal products on CVD, as well as some of its risk factors such as dyslipidemia, have been investigated previously. However, to the best of our knowledge, the effect of these natural products, including herbal supplements and functional foods (e.g. fruits and vegetables as either dry materials, or their extracts) on Apo B has not yet been investigated. Therefore, the primary objective of this paper was to review the effect of bioactive natural compounds on plasma Apo B concentrations. It is concluded that, in general, medicinal plants and nutraceuticals can be used as complementary medicine to reduce plasma Apo B levels in a safe, accessible, and inexpensive manner in an attempt to prevent and treat CVD.

Effect of Bempedoic Acid on atherogenic lipids and inflammation: A meta-analysis

BACKGROUND

Bempedoic acid is a novel non-statin drug that was developed to treat hyperlipidemia in combination with other lipid-lowering drugs in those patients who need additional lipid lowering.

OBJECTIVES

(1) To investigate the lipid efficacy of bempedoic acid; (2) to analyze the anti-inflammatory effects of bempedoic acid estimated through high sensitivity C-reactive protein (hsCRP).

METHODS

We performed a meta-analysis including randomized trials of bempedoic acid therapy, reporting low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), apolipoprotein B and hsCRP with a minimum of 4 weeks of follow-up. The primary endpoint was defined as the percentage change in lipids and hsCRP levels measured from baseline to follow-up, comparing groups of subjects on bempedoic acid versus placebo.

RESULTS

Seven eligible trials of bempedoic acid (3892 patients) were included. The bempedoic acid therapy was associated with a significant reduction in LDL-C levels [-20.3% (CI 95% -23.5 to -17.1)]; I²=43%]. Similarly, a significant percentage reduction in the apolipoprotein B levels [-14.3% (CI 95% -16.4 to -12.1)]; p<0.05; I²=46%], non-HDL-C levels [-15.5% (CI 95% -18.1 to -13.0)]; p<0.05; I²=53%] and hsCRP [-23.4% (CI 95% -32.6 to -14.2)]; p<0.05; I²=69%] was demonstrated with the bempedoic acid use. The sensitivity analysis showed that the results were robust.

CONCLUSION

Our data suggests that the use of bempedoic acid significantly reduces the levels of all atherogenic lipid markers, including LDL-C, non-HDL-C and apolipoprotein B. Furthermore, considering hsCRP levels, the drug produces an anti-inflammatory effect.

Dyslipidemia in childhood and adolescence: from screening to management

PURPOSE OF REVIEW

To summarize types of dyslipidemia frequently encountered during childhood and adolescence, with a focus on screening, diagnosis, and management.

RECENT FINDINGS

It is important that screening for atherosclerotic cardiovascular disease (ASCVD) begin in childhood. Genetic testing allows for increased awareness of dyslipidemia and more targeted intervention. Pharmacologic treatment of pediatric dyslipidemias has a good safety profile and can reduce adult ASCVD risk.

SUMMARY

Much of what is known about pediatric dyslipidemia has been extrapolated from adult data, but recently, there have been increasing investigations within the pediatric population to better guide diagnosis and management of these disorders.

Effects of High Levels of Dietary Linseed Oil on the Growth Performance, Antioxidant Capacity, Hepatic Lipid Metabolism, and Expression of Inflammatory Genes in Large Yellow Croaker (Larimichthys crocea)

A growth experiment was conducted to evaluate the effects of dietary fish oil (FO) replaced by linseed oil (LO) on the growth performance, antioxidant capacity, hepatic lipid metabolism, and expression of inflammatory genes in large yellow croaker (Larimichthys crocea). Fish (initial weight: 15.88 ± 0.14 g) were fed four experimental diets with 0% (the control), 33.3%, 66.7%, and 100% of FO replaced by LO. Each diet was randomly attributed to triplicate seawater floating cages (1.0 × 1.0 × 2.0 m) with 60 fish in each cage. Results showed that the growth performance of fish fed the diet with 100% LO was markedly decreased compared with the control group (P < 0.05), while no remarkable difference was observed in the growth performance of fish fed diets within 66.7% LO (P > 0.05). The percentage of 18:3n-3 was the highest in the liver and muscle of fish fed the diet with 100% LO among the four treatments. When dietary FO was entirely replaced by LO, fish had a markedly higher total cholesterol, total triglyceride, low-density lipoprotein cholesterol content, and alanine transaminase activity in the serum than the control group (P < 0.05). The concentration of malondialdehyde was markedly higher, while the activity of catalase was markedly lower in fish fed the diet with 100% LO than the control group (P < 0.05). When dietary FO was entirely replaced by LO, hepatic lipid content, transcriptional levels of fatp1 and cd36, and CD36 protein expression were significantly higher, while transcriptional level of cpt-1 and CPT-1 protein expression were significantly lower than the control group (P < 0.05). As for the gene expression of cytokines, fish fed the diet with 100% LO had markedly higher transcriptional levels of il-1β, tnfα, and il-6 than the control group (P < 0.05). In conclusion, the substitution of 66.7% FO with LO had no significant effects on the growth performance of fish, while 100% LO decreased the growth performance and increased the inflammation and hepatic lipid content of fish. The increase of hepatic lipid content was probably due to the increased fatty acid uptake and decreased fatty acid oxidation in fish.

Impacts of high fat diet on ocular outcomes in rodent models of visual disease

High fat diets (HFD) have been utilized in rodent models of visual disease for over 50 years to model the effects of lipids, metabolic dysfunction, and diet-induced obesity on vision and ocular health. HFD treatment can recapitulate the pathologies of some of the leading causes of blindness, such as age-related macular degeneration (AMD) and diabetic retinopathy (DR) in rodent models of visual disease. However, there are many important factors to consider when using and interpreting these models. To synthesize our current understanding of the importance of lipid signaling, metabolism, and inflammation in HFD-driven visual disease processes, we systematically review the use of HFD in mouse and rat models of visual disease. The resulting literature is grouped into three clusters: models that solely focus on HFD treatment, models of diabetes that utilize both HFD and streptozotocin (STZ), and models of AMD that utilize both HFD and genetic models and/or other exposures. Our findings show that HFD profoundly affects vision, retinal function, many different ocular tissues, and multiple cell types through a variety of mechanisms. We delineate how HFD affects the cornea, lens, uvea, vitreous humor, retina, retinal pigmented epithelium (RPE), and Bruch's membrane (BM). Furthermore, we highlight how HFD impairs several retinal cell types, including glia (microglia), retinal ganglion cells, bipolar cells, photoreceptors, and vascular support cells (endothelial cells and pericytes). However, there are a number of gaps, limitations, and biases in the current literature. We highlight these gaps and discuss experimental design to help guide future studies. Very little is known about how HFD impacts the lens, ciliary bodies, and specific neuronal populations, such as rods, cones, bipolar cells, amacrine cells, and retinal ganglion cells. Additionally, sex bias is an important limitation in the current literature, with few HFD studies utilizing female rodents. Future studies should use ingredient-matched control diets (IMCD), include both sexes in experiments to evaluate sex-specific outcomes, conduct longitudinal metabolic and visual measurements, and capture acute outcomes. In conclusion, HFD is a systemic exposure with profound systemic effects, and rodent models are invaluable in understanding the impacts on visual and ocular disease.

Understanding the role of lipids and lipoproteins in development

Lipids exert diverse functions in living organisms. They form cellular membranes, store and transport energy and play signalling roles. Some lipid species function in all of these processes, making them ideal candidates to coordinate metabolism with cellular homeostasis and animal development. This theme was central to Suzanne Eaton's research in the fruit fly, Drosophila Here, we discuss her work on membrane lipid homeostasis in changing environments and on functions for lipids in the Hedgehog signalling pathway. We further highlight lipoproteins as inter-organ carriers of lipids and lipid-linked morphogens, which communicate dietary and developmental signals throughout the organism.