Capacity of HDL to Efflux Cellular Cholesterol from Lipid-Loaded Macrophages Is Reduced in Patients with Familial Hypercholesterolemia

Emerging Biomarkers and Determinants of Lipoprotein Profiles to Predict CVD Risk: Implications for Precision Nutrition

Biomarkers constitute a valuable tool to diagnose both the incidence and the prevalence of chronic diseases and may help to inform the design and effectiveness of precision nutrition interventions. Cardiovascular disease (CVD) continues to be the foremost cause of death all over the world. While the reasons that lead to increased risk for CVD are multifactorial, dyslipidemias, plasma concentrations of specific lipoproteins, and dynamic measures of lipoprotein function are strong biomarkers to predict and document coronary heart disease incidence. The aim of this review is to provide a comprehensive evaluation of the biomarkers and emerging approaches that can be utilized to characterize lipoprotein profiles as predictive tools for assessing CVD risk, including the assessment of traditional clinical lipid panels, measures of lipoprotein efflux capacity and inflammatory and antioxidant activity, and omics-based characterization of lipoprotein composition and regulators of lipoprotein metabolism. In addition, we discuss demographic, genetic, metagenomic, and lifestyle determinants of lipoprotein profiles-such as age, sex, gene variants and single-nucleotide polymorphisms, gut microbiome profiles, dietary patterns, physical inactivity, obesity status, smoking and alcohol intake, and stress-which are likely to be essential factors to explain interindividual responses to precision nutrition recommendations to mitigate CVD risk.

PCSK9 Antibodies Treatment Specifically Enhances the Macrophage-specific Reverse Cholesterol Transport Pathway in Heterozygous Familial Hypercholesterolemia

We investigated the potential of proprotein convertase subtilisin/kexin type 9 (PCSK9) antibodies to restore macrophage cholesterol efflux in subjects with heterozygous familial hypercholesterolemia (FH) and to enhance the macrophage-specific reverse cholesterol transport pathway in mice. Analyses of macrophage-derived cholesterol distribution of plasma from FH patients revealed that low-density lipoprotein (LDL) particles contained less, and high-density lipoprotein particles contained more radiolabeled cholesterol after treatment with either PCSK9 inhibitor. PCSK9 antibodies facilitated the transfer of macrophage-derived cholesterol and LDL-derived cholesterol to feces exclusively in heterozygous LDL receptor-deficient mice expressing human APOB100. PCSK9 inhibitors act as positive regulators of the macrophage-specific reverse cholesterol transport pathway in individuals with heterozygous FH.

Clinical impact of genetic testing for lipid disorders

PURPOSE OF REVIEW

Genetic testing is increasingly becoming a common consideration in the clinical approach of dyslipidemia patients. Advances in research in last decade and increased recognition of genetics in biological pathways modulating blood lipid levels created a gap between theoretical knowledge and its applicability in clinical practice. Therefore, it is very important to define the clinical justification of genetic testing in dyslipidemia patients.

RECENT FINDINGS

Clinical indications for genetic testing for most dyslipidemias are not precisely defined and there are no clearly established guideline recommendations. In patients with severe low-density lipoprotein cholesterol (LDL-C) levels, the genetic analysis can be used to guide diagnostic and therapeutic approach, while in severe hypertriglyceridemia (HTG), clinicians can rely on triglyceride level rather than a genotype along the treatment pathway. Genetic testing increases diagnostic accuracy and risk stratification, access and adherence to specialty therapies, and cost-effectiveness of cascade testing. A shared decision-making model between the provider and the patient is essential as patient values, preferences and clinical characteristics play a very strong role.

SUMMARY

Genetic testing for lipid disorders is currently underutilized in clinical practice. However, it should be selectively used, according to the type of dyslipidemia and when the benefits overcome costs.

The Association between High-density Lipoproteins and Periodontitis

Periodontitis is one of the most typical chronic dental diseases. This inflammatory disease can change various functions of immune cells and impair lipid metabolism through proinflammatory cytokines. High-Density Lipoprotein (HDL) is considered protective of the cardiovascular system. It has anti-thrombotic and anti-inflammatory effects. In this article, we have reviewed the association between periodontitis and HDL. Various studies have demonstrated a reverse relationship between inflammatory cytokines and HDL. HDL contains antioxidative enzymes and proteins, whereas periopathogens impair HDL's antioxidant function. The presence of periodontal bacteria is associated with a low HDL level in patients with periodontitis. Genetic variants in the interleukin- 6 (IL)-6 gene and cytochrome (CYP)1A1 rs1048943 gene polymorphism are associated with HDL levels and periodontal status. Studies showed that HDL levels improve after treatment for periodontitis. On the one hand, periodontal pathogenic bacteria and their metabolites and pro-inflammatory cytokines from periodontal infection can result in various disorders of lipid metabolism and lipid peroxidation. On the other hand, hyperlipidemia and lipid peroxidation stimulate proinflammatory cytokines, resulting in oxidative stress and delayed wound healing, making individuals susceptible to periodontitis.

Sex-Specific Relationships between HDL-Cholesterol Levels and 10-Year Mortality in Individuals with Atherosclerotic Cardiovascular Disease: A Nationwide Cohort Study of South Koreans

Large epidemiological studies show U-shaped relationships between high-density lipoprotein cholesterol (HDL-C) levels and all-cause mortality in individuals without atherosclerotic cardiovascular diseases (ASCVD). Association in those with ASCVD by sex is unclear. We examined the association between HDL-C levels and 10-year all-cause mortality in subjects (≥40 years of age) with ASCVD using the 2010 National Health Insurance Service and the National Death Registry of Korea. We categorized HDL-C levels into three groups (low: <40 mg/dL for males, <50 mg/dL for females; high: 40-90 mg/dL for males, 50-90 mg/dL for females; extremely high: >90 mg/dL) and 10 mg/dL intervals. We conducted a sex-stratified and adjusted Cox proportional hazards analysis. Out of 1,711,548 individuals (54% female, mean age 61.4 years), 10-year mortality was observed in 218,252 (12.8%). Males had a higher mortality rate than females (16.2% vs. 9.8%; p < 0.001). When adjusting for age, body mass index, LDL-cholesterol, triglycerides, hypertension, diabetes, smoking, and alcohol consumption, the low and extremely high HDL-C groups had significantly higher hazard ratios for 10-year mortality compared to the high HDL-C group in males [1.183 (1.166-1.199), 1.359 (1.288-1.434)] and in females [1.153 (1.138-1.169), 1.095 (1.029-1.167)]. The frequency distribution bars for the 10-year mortality rate showed sex-specific nadirs of 50-59 mg/dL in males and 70-79 mg/dL in females. In this ASCVD cohort, the extremely high HDL-C (>90 mg/dL) group had 35.9% and 9.5% higher 10-year mortality risks than the high HDL-C group for males and females, respectively. There was a slightly U-shaped relationship between baseline HDL-C levels and a 10-year mortality rate, with earlier inflection in males than in females.