Beyond the Guidelines: Perspectives on Management of Pediatric Patients with Hypertriglyceridemia.

PURPOSE OF REVIEW: To provide a comprehensive overview of hypertriglyceridemia (HTG) in youth, identifying gaps in categorizing triglyceride (TG) levels and management strategies, and exploring new therapies for TG reduction. RECENT FINDINGS: Non-fasting TG levels as important cardiovascular (CV) risk indicators, with HTG's pathophysiology involving genetic and secondary factors affecting TG metabolism. Emerging treatments, including those affecting the lipoprotein lipase complex and inhibiting proteins like apoC3 and ANGPTL3, show promise. The review highlights the need for specific management approaches for youth, the significance of non-fasting TG levels, and the potential of new therapies in reducing CV and pancreatitis risks, advocating for further research on these treatments' efficacy and safety.

Gradual Increase in Inflammation-Linked Glycoproteins and a Proatherogenic Lipoprotein Profile in the Early Stages of Psychosis as Characterized by 1H NMR Blood Analysis.

Minimally invasive prognostic markers of inflammation and dyslipidemia in individuals with a risk of psychosis, also called "at-risk mental state" (ARMS), or in the first episode of psychosis (FEP) are of utmost clinical importance to prevent cardiovascular disorders. We analyzed the plasma concentration of inflammation-linked glycoproteins (Glycs) and lipoprotein subclasses by proton nuclear magnetic resonance (1H NMR) in a single acquisition. Study participants were healthy controls (HCs, N = 67) and patients with ARMS (N = 58), FEP (N = 110), or early psychosis diagnosis with ≥2 episodes (critical period (CP), N = 53). Clinical biomarkers such as high-sensitivity C-reactive protein, interleukin 6, fibrinogen, insulin, and lipoproteins were also measured. Although all participants had normal lipoprotein profiles and no inflammation according to conventional biomarkers, a gradual increase in the Glyc 1H NMR levels was observed from HCs to CP patients; this increase was statistically significant for GlycA (CP vs HC). In parallel, a progressive and significant proatherogenic 1H NMR lipoprotein profile was also identified across stages of psychosis (ARMS and CP vs HC). These findings highlight the potential of using 1H NMR Glyc and lipoprotein profiling to identify blood changes in individuals with ARMS or FEP and pave the way for applications using this technology to monitor metabolic and cardiovascular risks in clinical psychiatry.

Inflammatory Links Between Hypertriglyceridemia and Atherogenesis.

PURPOSE OF REVIEW: Recent studies indicate an association between hypertriglyceridemia (HTG) and atherosclerotic cardiovascular disease (ASCVD). The purpose of this review is to discuss the potential mechanism connecting HTG and ASCVD risk and the potential efficacy of HTG-targeting therapies in ASCVD prevention. RECENT FINDINGS: HTG, with elevations in triglyceride-rich lipoproteins (TGRL) and their remnants, are causal ASCVD risk factors. The mechanisms whereby HTG increases ASCVD risk are not well understood but may include multiple factors. Inflammation plays a crucial role in atherosclerosis. TGRL compared to low-density lipoproteins (LDL) correlate better with inflammation. TGRL remnants can penetrate endothelium and interact with macrophages leading to foam cell formation and inflammation in arterial walls, thereby contributing to atherogenesis. In addition, circulating monocytes can take up TGRL and become lipid-laden foamy monocytes, which infiltrate the arterial wall and may also contribute to atherogenesis. Novel therapies targeting HTG or inflammation are in development and have potential of reducing residual ASCVD risk associated with HTG. Clinical and preclinical studies show a causal role of HTG in promoting ASCVD, in which inflammation plays a vital role. Novel therapies targeting HTG or inflammation have potential of reducing residual ASCVD risk.

Increased particle size of triacylglycerol-enriched remnant lipoproteins, but not their plasma concentration or lipid content, augments risk prediction of incident type 2 diabetes.

AIMS/HYPOTHESIS: Type 2 diabetes prevention requires the accurate identification of those at high risk. Beyond the association of fasting serum triacylglycerols with diabetes, triacylglycerol-enriched remnant lipoproteins (TRLs) more accurately reflect pathophysiological changes that underlie progression to diabetes, such as hepatic insulin resistance, pancreatic steatosis and systemic inflammation. We hypothesised that TRL-related factors could improve risk prediction for incident diabetes. METHODS: We included individuals from the Brazilian Longitudinal Study of Adult Health cohort. We trained a logistic regression model for the risk of incident diabetes in 80% of the cohort using tenfold cross-validation, and tested the model in the remaining 20% of the cohort (test set). Variables included medical history and traits of the metabolic syndrome, followed by TRL-related measurements (plasma concentration, TRL particle diameter, cholesterol and triacylglycerol content). TRL features were measured using NMR spectroscopy. Discrimination was assessed using the area under the receiver operating characteristic curve (AUROC) and the area under the precision-recall curve (AUPRC). RESULTS: Among 4463 at-risk individuals, there were 366 new cases of diabetes after a mean (±SD) of 3.7 (±0.63) years of follow-up. We derived an 18-variable model with a global AUROC of 0.846 (95% CI: 0.829, 0.869). Overall TRL-related markers were not associated with diabetes. However, TRL particle diameter increased the AUROC, particularly in individuals with HbA1c <39 mmol/mol (5.7%) (hold-out test set [n = 659]; training-validation set [n = 2638]), but not in individuals with baseline HbA1c 39-46 mmol/mol (5.7-6.4%) (hold-out test set [n = 233]; training-validation set [n = 933]). In the subgroup with baseline HbA1c <39 mmol/mol (5.7%), AUROC in the test set increased from 0.717 (95% CI 0.603, 0.818) to 0.794 (95% CI 0.731, 0.862), and AUPRC in the test set rose from 0.582 to 0.701 when using the baseline model and the baseline model plus TRL particle diameter, respectively. TRL particle diameter was highly correlated with obesity, insulin resistance and inflammation in those with impaired fasting glucose at baseline, but less so in those with HbA1c <39 mmol/mol (5.7%). CONCLUSIONS/INTERPRETATION: TRL particle diameter improves the prediction of diabetes, but only in individuals with HbA1c <39 mmol/mol (5.7%) at baseline. These data support TRL particle diameter as a risk factor that is changed early in the course of the pathophysiological processes that lead to the development of type 2 diabetes, even before glucose abnormalities are established. Graphical abstract.

Evaluation of atherogenic lipoprotein-cholesterol to HDL cholesterol ratio as a prognostic test for ST-segment elevation myocardial infarction.

Background: The detectable component of triglyceride-rich lipoproteins (TGRLs), remnant lipoprotein cholesterol (RLP-c), has been proven being correlated with the progression of atherosclerosis and myocardial infarction. However, when taken as a risk predictor, the prognostic and diagnostic potential of RLP-c remains controversial in studies. In this study, we evaluated the hypothesis that atherogenic lipoprotein-cholesterol (AL-c), representing the sum of RLP-c and the sd-LDL-c, to the HDL-c ratio, could represent a better predictive indicator than RLP-c alone in ST-segment elevation myocardial infarction (STEMI). Methods: The 316 consecutive patients suffering from persistent chest discomfort admitted to the Shanghai General Hospital between January 2018 and June 2018 were enrolled. 149 STEMI patients (62% men, mean age 69.6 ± 13.3 years) were included as the study cohort. The AL-c/HDL-c ratio was calculated on admission in a cohort of electrocardiogram-confirmed STEMI patients and compared to other lipid profiles as a predictive indicator. Results: The AL-c/HDL-c ratio was significantly increased in STEMI patients compared with apparently healthy adults (0.93; IQR [0.71-1.18] vs 0.70; IQR [0.45-1.04]; p < 0.001). Gender dependency existed, and the male and female patients had median AL-c/HDL-c ratios of 1.01 and 0.79, respectively (p < 0.001). Compared to RLP-c, the AL-c/HDL-c ratio had a better prognostic value to predict STEMI risk in both sexes (AUC of 0.672 with a sensitivity of 0.794 in males and 0.613 with a sensitivity of 0.684 in females). Conclusions: The AL-c/HDL-c ratio could represent a convenient and sensitive biomarker for screening and predicting STEMI risk.

Associations between remnant lipoprotein cholesterol and central systolic blood pressure in a Chinese community-based population: a cross-sectional study.

BACKGROUND: The lipid profile is reportedly related to peripheral blood pressure or pulse wave velocity. However, no studies have investigated the associations between lipid parameters, especially remnant lipoprotein cholesterol (RLP-C), and central systolic blood pressure (cSBP). METHODS: This study used baseline data of a community-based cohort in Beijing, China. Participants who had been treated with anti-hypertensive or lipid-lowering agents were excluded. RLP-C is equal to total cholesterol (TC) minus the sum of low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). An Omron HEM-9000AI device was used to measure non-invasive cSBP. The associations between blood lipid profile and non-invasive cSBP were evaluated using multivariable regression models. RESULTS: The 5173 included participants were 55.0 ± 8.5 years old; 35.7% (1845) of participants were men. Increased cSBP was significantly associated with increased TC, LDL-C, non-high-density lipoprotein cholesterol (non-HDL-C), triglyceride (TG), and RLP-C but with decreased HDL-C, even after adjusting for possible covariates. When simultaneously entering individual pairs of RLP-C and other blood lipid parameters into the multivariable regression model, RLP-C remained significantly associated with cSBP, even after adjusting for other lipids. Compared with participants who had RLP-C levels in the first quartile (Q1), cSBP for those with RLP-C in Q4 was increased to 4.57 (95% confidence interval [CI]: 3.08-6.06) mmHg after adjusting for LDL-C, 4.50 (95%CI: 2.98-6.02) mmHg after adjusting for TC, 3.91 (95%CI: 1.92-5.89) mmHg after adjusting for TG, 5.15 (95%CI: 3.67-6.63) mmHg after adjusting for HDL-C, and 4.10 (95%CI: 2.36-5.84) mmHg after adjusting for non-HDL-C. CONCLUSIONS: Increased blood RLP-C level was significantly associated with higher cSBP in a Chinese population, independently of other lipids, which indicates its importance in individual cardiovascular risk assessment.

Prevalence of Dysbetalipoproteinemia in the UK Biobank According to Different Diagnostic Criteria.

CONTEXT: Dysbetalipoproteinemia (DBL) is a multifactorial disorder that disrupts the normal metabolism of remnant lipoproteins, causing increased risk of cardiovascular disease. However, establishing a proper diagnosis is difficult and the true prevalence of the disease in the general population remains unknown. OBJECTIVE: The objectives were to study the prevalence of the disease and to validate the performance of different clinical diagnostic criteria in a large population-based cohort. METHODS: This study included 453 437 participants from the UK Biobank. DBL was established in participants having an ε2ε2 genotype with mixed dyslipidemia or lipid-lowering therapy use (n=964). The different diagnostic criteria for DBL were applied in individuals without lipid-lowering medication (n=370 039, n=534 DBL), to compare their performance. RESULTS: Overall, 0.6% of participants had an ε2ε2 genotype, of which 36% were classified as DBL, for a disease prevalence of 0.2% (1:469). The prevalence of DBL was similar between the different genetic ancestries (≤0.2%). Several diagnostic criteria showed good sensitivity for the diagnosis of DBL (>90%), but they suffered from a very low positive predictive value (0.6%-15.4%). CONCLUSION: This study reported for the first time the prevalence of DBL in the UK Biobank according to genetic ancestry. Furthermore, we provided the first external validation of different diagnostic criteria for DBL in a large population-based cohort and highlighted the fact that these criteria should not be used to diagnose DBL alone but should rather be used as a first screening step to determine which individuals may benefit from genetic testing to confirm the diagnosis.

Predictors of cardiovascular disease in individuals with dysbetalipoproteinemia: a prospective study in the UK Biobank.

BACKGROUND: Dysbetalipoproteinemia (DBL) is a disorder of remnant cholesterol metabolism associated with a severe risk of atherosclerotic cardiovascular disease (ASCVD). OBJECTIVE: The objective of this study was to investigate the univariate and multivariate predictors of ASCVD in individuals with DBL. METHODS: Data from 2,699 individuals with ε2/ε2 genotypes from the UK Biobank were included in this study. DBL was defined as having an ε2ε2 genotype with evidence of dyslipidemia, defined as total cholesterol ≥ 200 mg/dL [5.2 mmol/L] and TG ≥ 175 mg/dL [2.0 mmol/L]) or lipid-lowering therapy use (n=964). RESULTS: Age, hypertension, waist circumference and a polygenic risk score for coronary artery disease (PRSCAD) were independent predictors of ASCVD among individuals with DBL. Cumulative ASCVD-free survival was lower in the ε2/ε2 DBL group (84%) compared to the ε2/ε2 non-DBL group (94%) (p<0.0001), and for DBL individuals with a PRSCAD ≥ median (79%) compared to those with a PRSCAD < median (89%) (p=0.001). CONCLUSION: We show in a large prospective cohort that a PRSCAD predicts the ASCVD risk among individuals with DBL. The findings of the present study highlight the need for better risk stratification in ε2/ε2 carriers to identify high risk individuals that would need aggressive cardiovascular management despite their low apolipoprotein B value.

It is time to address the contribution of cholesterol in all apoB-containing lipoproteins to atherosclerotic cardiovascular disease.

On average, LDL particles are the most populous lipoprotein in serum under fasting conditions. For many reasons, it has been the primary target of lipid-lowering guidelines around the world. In the past 30 years, we have witnessed remarkable changes in each iteration of dyslipidaemia guidelines, with LDL-cholesterol (LDL-C) targets becoming lower and lower among patients at high and very high risk for atherosclerotic cardiovascular disease (ASCVD). The world over, goal attainment rates are low, and hence, ASCVD prevalence remains unacceptably high. Inadequate LDL-C lowering is a major issue in contemporary cardiovascular (CV) medicine. Another issue that vexes even the most astute clinician is that of 'residual risk', meaning the excess risk that remains even after LDL-C is appropriately reduced. In recent years, an important new component of residual risk has emerged: triglyceride-enriched lipoproteins or remnant lipoproteins. These precursors to LDL particles can assume outsized importance among patients with derangements in triglyceride metabolism (e.g. genetic variants, insulin resistance, and diabetes mellitus) and may be more atherogenic than LDL species. Consequently, to reduce total risk for acute CV events, the time has come to include the entire spectrum of apoB-containing lipoproteins in approaches to both risk evaluation and treatment.

Plasma proprotein convertase subtilisin kexin type 9 levels are related to markers of cholesterol synthesis in familial combined hyperlipidemia.

BACKGROUND AND AIMS: Two recent independent studies showed that patients with familial combined hyperlipidemia (FCHL) have elevated plasma levels of proprotein convertase subtilisin kexin type 9 (PCSK9) and markers of cholesterol synthesis. Both PCSK9 expression and cholesterol synthesis are downstream effects of hepatic activation of sterol regulatory element binding protein 2 (SREBP2). The present study was conducted to study the relationship between plasma PCSK9 and markers of cholesterol synthesis in FCHL. METHODS AND RESULTS: Markers of cholesterol synthesis (squalene, desmosterol, lathosterol), cholesterol absorption (campesterol, sitosterol, cholestanol) and PCSK9 were measured in plasma of FCHL patients (n = 103) and their normolipidemic relatives (NLR; n = 240). Plasma PCSK9, lathosterol and desmosterol levels were higher in FCHL patients than their NLR (p < 0.001, age and sex adjusted). Heritability calculations demonstrated that 35% of the variance in PCSK9 levels could be explained by additive genetic effects (p < 0.001). Significant age- and sex-adjusted correlations were observed for the relationship between PCSK9 and lathosterol, both unadjusted and adjusted for cholesterol, in the overall FCHL population (both p < 0.001). Multivariate regression analyses, with PCSK9 as the dependent variable, showed that the regression coefficient for FCHL status decreased by 25% (from 0.8 to 0.6) when lathosterol was included. Nevertheless, FCHL status remained an independent contributor to plasma PCSK9 (p < 0.001). CONCLUSIONS: The present study confirms the previously reported high and heritable PCSK9 levels in FCHL patients. Furthermore, we now show that high PCSK9 levels are, in part, explained by plasma lathosterol, suggesting that SREBP2 activation partly accounts for elevated PCSK9 levels in FCHL.

Significance of Circulating Remnant Lipoprotein Cholesterol Levels Measured by Homogeneous Assay in Patients with Type 2 Diabetes.

Remnant lipoproteins (RLs), which are typically present at high concentrations in patients with type 2 diabetes mellitus (T2DM), are associated with cardiovascular disease (CVD). Although an RL cholesterol homogeneous assay (RemL-C) is available for the measurement of RL concentrations, there have been no studies of the relationship between RemL-C and clinical parameters in T2DM. Therefore, we evaluated the relationships between RemL-C and CVD-related parameters in patients with T2DM. We performed a cross-sectional study of 169 patients with T2DM who were hospitalized at Kumamoto University Hospital. Compared with those with low RemL-C, those with higher RemL-C had higher fasting plasma glucose, homeostasis model assessment for insulin resistance (HOMA-R), total cholesterol, triglyceride, small dense low-density lipoprotein cholesterol (sdLDL-C), and urinary albumin-creatinine ratio; and lower high-density lipoprotein cholesterol, adiponectin, and ankle brachial pressure index (ABI). Multivariate logistic regression analysis showed that sdLDL-C and ABI were significantly and independently associated with high RemL-C. Although LDL-C was lower in participants with CVD, there was no difference in RemL-C between participants with or without CVD. Thus, RemL-C may represent a useful index of lipid and glucose metabolism, and that may be a marker of peripheral atherosclerotic disease (PAD) in male patients with T2DM.

The Role of Triglyceride-rich Lipoproteins and Their Remnants in Atherosclerotic Cardiovascular Disease.

Atherosclerotic cardiovascular disease (ASCVD) is the world's leading cause of death. ASCVD has multiple mediators that therapeutic interventions target, such as dyslipidaemia, hypertension, diabetes and heightened systemic inflammatory tone, among others. LDL cholesterol is one of the most well-studied and established mediators targeted for primary and secondary prevention of ASCVD. However, despite the strength of evidence supporting LDL cholesterol reduction by multiple management strategies, ASCVD events can still recur, even in patients whose LDL cholesterol has been very aggressively reduced. Hypertriglyceridaemia and elevated levels of triglyceride-rich lipoproteins (TRLs) may be key contributors to ASCVD residual risk. Several observational and genetic epidemiological studies have highlighted the causal role of triglycerides within the TRLs and/or their remnant cholesterol in the development and progression of ASCVD. TRLs consist of intestinally derived chylomicrons and hepatically synthesised very LDL. Lifestyle modification has been considered the first line intervention for managing hypertriglyceridaemia. Multiple novel targeted therapies are in development, and have shown efficacy in the preclinical and clinical phases of study in managing hypertriglyceridaemia and elevated TRLs. This comprehensive review provides an overview of the biology, pathogenicity, epidemiology, and genetics of triglycerides and TRLs, and how they impact the risk for ASCVD. In addition, we provide a summary of currently available and novel emerging triglyceride-lowering therapies in development.

Dysbetalipoproteinemia: Differentiating Multifactorial Remnant Cholesterol Disease From Genetic ApoE Deficiency.

CONTEXT: Dysbetalipoproteinemia (DBL) is characterized by the accumulation of remnant lipoprotein particles and associated with an increased risk of cardiovascular and peripheral vascular disease (PVD). DBL is thought to be mainly caused by the presence of an E2/E2 genotype of the apolipoprotein E (APOE) gene, in addition to environmental factors. However, there exists considerable phenotypic variability among DBL patients. OBJECTIVE: The objectives were to verify the proportion of DBL subjects, diagnosed using the gold standard Fredrickson criteria, who did not carry E2/E2 and to compare the clinical characteristics of DBL patients with and without E2/E2. METHODS: A total of 12 432 patients with lipoprotein ultracentrifugation as well as APOE genotype or apoE phenotype data were included in this retrospective study. RESULTS: Among the 12 432 patients, 4% (n = 524) were positive for Fredrickson criteria (F+), and only 38% (n = 197) of the F+ individuals were E2/E2. The F+ E2/E2 group had significantly higher remnant cholesterol concentration (3.44 vs 1.89 mmol/L) and had higher frequency of DBL-related xanthomas (24% vs 2%) and floating beta (95% vs 11%) than the F+ non-E2/E2 group (P < 0.0001). The F+ E2/E2 group had an independent higher risk of PVD (OR 11.12 [95% CI 1.87-66.05]; P = 0.008) events compared with the F+ non-E2/E2 group. CONCLUSION: In the largest cohort of DBL worldwide, we demonstrated that the presence of E2/E2 was associated with a more severe DBL phenotype. We suggest that 2 DBL phenotypes should be distinguished: the multifactorial remnant cholesterol disease and the genetic apoE deficiency disease.

Remnant Lipoprotein Cholesterol as a Factor Related to Adult Fatty Liver Disease.

CONTEXT: Dyslipidemia is related to fatty liver disease (FLD), whose relationship with remnant lipoprotein cholesterol (RLP-C), a component of blood lipids, remains unclear. OBJECTIVE: To clarify the correlation between RLP-C and the occurrence and severity of FLD and establish an FLD discriminant model based on health check indicators. METHODS: Retrospective study of participants who underwent health check-up in the First Affiliated Hospital of China Medical University (Shenyang, China) between January and December 2019. We categorized participants according to liver ultrasound results and analyzed the correlation between RLP-C and occurrence of FLD (n = 38 885) through logistic regression, restricted cubic spline, and receiver operating characteristic curve. We categorized the severity of FLD according to the control attenuation parameter and analyzed the correlation between RLP-C and FLD severity through multiple logistic regression; only males were included (n = 564). RESULTS: The adjusted OR (aOR) per SD between RLP-C and FLD was 2.33 (95% CI 2.21-2.46, P < .001), indicating a dose-response relationship (P < .0001). The optimal cut-off value of RLP-C was 0.45 mmol/L and the area under the curve (AUC) was 0.79. The AUC of the 8-variable model was 0.89 in both the training and the validation sets. FLD severity was related to the level of RLP-C (aOR per SD = 1.29, 95% CI 1.07-1.55, P = .008). CONCLUSION: RLP-C has a strong positive correlation with FLD occurrence and FLD severity. These results may help clinicians identify and implement interventions in individuals with high FLD risk and reduce FLD prevalence.

Association between remnant lipoprotein cholesterol, high-sensitivity C-reactive protein, and risk of atherosclerotic cardiovascular disease events in the Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND: Elevated remnant-lipoprotein (RLP)-cholesterol (RLP-C) and high-sensitivity C-reactive protein (hsCRP) are each individually associated with atherosclerotic cardiovascular disease (ASCVD). OBJECTIVE: To evaluate the interplay of nuclear magnetic resonance (NMR)-derived RLP-C and hsCRP and their association with ASCVD in the Multi-Ethnic Study of Atherosclerosis (MESA). METHODS: Lipoprotein particles were measured using NMR spectroscopic analysis at baseline. RLP-C includes very-low-density lipoprotein cholesterol and intermediate-density lipoprotein cholesterol. Four groups were created as follows: Group 1: RLP-C ≤ median (≤29.14 mg/dL) and hsCRP < 2 mg/L; Group 2: RLP-C ≤ median and hsCRP≥ 2 mg/L; Group 3: RLP-C > median and hsCRP level < 2 mg/L; and Group 4: RLP-C > median and hsCRP level ≥ 2 mg/L. Kaplan-Meier survival curves and multivariable-adjusted Cox proportional hazard models were used to examine the relationship between RLP-C and hsCRP with incident ASCVD. RESULTS: A total of 6,720 MESA participants (mean age 62.2 y, 53% female) with a median follow-up of 15.6 years were included. In the fully adjusted model, compared to those in the reference group (Group 1), participants in Group 2, Group 3, and Group 4 demonstrated a 20% (95% CI, -2%-48%), 18% (-4%-44%), and 43% (18%-76%) increased risk of incident ASCVD events, respectively (p < 0.01). An additive and multiplicative interaction between RLP-C and hsCRP was not statistically significant. CONCLUSION: NMR-derived RLP-C and hsCRP showed a similar independent association with incident ASCVD. Notably, the combination of increased RLP-C and hsCRP was associated with an increased risk of future ASCVD events.

Comparison of low-density lipoprotein cholesterol level calculated using the modified Martin/Hopkins estimation or the Friedewald formula with direct homogeneous assay measured low-density lipoprotein cholesterol.

Introduction: Low-density lipoprotein cholesterol (LDL-C) represents the primary lipoprotein target for reducing cardiovascular risk (CV). The aim of our study is to compare the direct and the calculated LDL-C levels in the range below 1.8 mmol/l and 2.6 mmol/l depending on triglycerides, and to evaluate the variation in remnant lipoprotein cholesterol. Material and methods: We investigated 14 906 lipid profiles from fasting blood samples of Hungarian individuals with triglycerides < 4.5 mmol/l. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG) and direct LDL-C were measured by the enzymatic assay. We calculated LDL-C by Friedewald's formula (F-LDL-C) and by using the new Martin/Hopkins estimation (MH-LDL-C). Results: For F-LDL-C below 1.8 mmol/l, MH-LDL-C was 58% between 1.8 and 2.59 mmol/l when TG was in the range 2.3-4.5 mmol/l. For F-LDL-C below 2.6 mmol/l, the MH-LDL-C concordance was 73% in the same TG range (2.3-4.5 mmol/l. If MH-LDL-C was less than 1.8 mmol/l or between 1.8 and 2.59 mmol/l, the difference between non-HDL-C (TC - HDL-C = AC: atherogenic cholesterol) and (MH)LDL-C was less than 0.8 mmol/l in the TG range below 2.3 mmol/l. The remnant lipoprotein cholesterol values were on average 0.5 mmol/l lower by the Martin/Hopkins estimation compared to the Friedewald's calculation if the TG was above 2.3 mmol/l. Conclusions: The Friedewald equation tends to underestimate LDL-C levels in very high and high-risk settings. Our analysis supports the conclusion that in Hungarian patients, LDL-C estimation using the Martin/Hopkins formula, which is validated by the beta-quantification method, yields a more accurate LDL-C value than that calculated by the Friedewald formula.

Redox index of Cys-thiol residues of serum apolipoprotein E and its diagnostic potential.

BACKGROUND: The redox modulation of Cys-thiol participates in various pathophysiological processes. We explored the proper index for estimating the redox status of Cys-thiol of serum apolipoprotein E (apoE), named "redox-IDX-apoE," which is necessary to understand the redox biology of age-related diseases. METHODS: The fractions of the reduced form (red-), reversible oxidized form (roxi-), and irreversibly oxidized form (oxi-) apoE in serum, obtained from the patients with no apparent disease (controls, n=192) and with atherosclerosis and type 2 diabetes (patients, n=16), were measured by a band-shift assay using a maleimide compound. Redox-IDX-apoE candidates were determined by calculating the values of these fractions and the total apoE concentration. RESULTS: Cys number of apoE significantly increased for the ratio of roxi-apoE to total-apoE (roxi/total) (E2/E3>E3/E3>E3/E4) but decreased for the ratios of red-apoE to roxi-apoE (red/roxi) and [red-apoE + oxi-apoE] to roxi-apoE ([red + oxi]/roxi) (E2/E3

The role of triglycerides in the origin and progression of atherosclerosis.

Hypertriglyceridaemia has been associated with cardiovascular disease risk in humans for several decades. However, only recently, data from basic research, as well as from genetic and observational studies, have suggested triglyceride-rich lipoproteins (TRLs) as causal factors for atherosclerotic cardiovascular disease. Novel findings highlighting the relevance of TRL-derived lipolytic products (remnant lipoprotein particles "RLPs"), rather than plasma triglycerides or TRL themselves, as the true mediators in atherosclerosis, have contributed to explain a causal relationship through a number of direct and indirect mechanisms. Thus, experimental studies in animal models and in vitro cell culture methods reveal that RLPs, having sizes below 70-80nm, enter the arterial wall and accumulate within the sub-endothelial space. They then become involved in the cholesterol deposition of cholesterol in the intima in addition to several pro-inflammatory and pro-apoptotic pathways. In this review, a summary is presented of current understanding of the pathophysiological mechanisms by which TRLs and their lipolytic derived RLP induce the formation and progression of atherosclerotic lesions, and actively contribute to cardiovascular disease.

A simplified diagnosis algorithm for dysbetalipoproteinemia.

BACKGROUND: Dysbetalipoproteinemia (DBL) is a disease of remnant lipoprotein accumulation caused by a defective apolipoprotein (apo) E and is associated with a considerable atherogenic burden. However, there exists confusion concerning the diagnosis of this disorder, and as a consequence, misdiagnosis is frequent. OBJECTIVE: The objective of the present study is to propose an algorithm for the diagnosis of DBL using simple clinical variables. METHODS: In a large cohort of 12,434 dyslipidemic patients, 4891 patients presented with mixed dyslipidemia (total cholesterol ≥ 5.2 mmol/L [200 mg/dL] and triglycerides ≥ 2.0 mmol/L [175 mg/dL]), and 188 DBL patients were identified based on the presence of an elevated very-low-density lipoprotein cholesterol/triglyceride ratio and were carriers of apoE2/E2. The APOE genotype or phenotype as well as the lipoprotein ultracentrifugation results were available for all patients. RESULTS: Among the laboratory variables associated with the lipid profile, the non-high-density lipoprotein cholesterol (HDL-C)/apoB ratio was the best predictor of DBL diagnosis based on the C-statistic. Previous proposed criteria had either low sensitivity or low specificity for the diagnosis of DBL. Using a non-HDL-C/apoB cut point of 3.69 mmol/g (1.43 in conventional units) followed by the presence of apoE2/E2 resulted in a good sensitivity (94.8%), negative predictive value (99.8%), specificity (99.6%), positive predictive value (88.5%), accuracy (99.4%), and area under the curve (0.97 [0.95-0.99]) for the prediction of DBL. CONCLUSION: We therefore propose a 3-step algorithm for the diagnosis of DBL using total cholesterol and triglycerides as a first step, the non-HDL-C/apoB ratio as a second screening criterion and finally the APOE genotype, lipoprotein ultracentrifugation, or electrophoresis as a confirmatory test.

Association between remnant lipoprotein cholesterol levels and non-alcoholic fatty liver disease in adolescents.

BACKGROUND & AIMS: Remnant lipoprotein cholesterol (RLP-C) is an atherogenic lipid profile associated with non-alcoholic fatty liver disease (NAFLD) and cardiovascular disease (CVD). With increased rates of CVD seen in adults with NAFLD, RLP-C has the potential to identify individuals with NAFLD who are at increased risk of CVD. This study examined in adolescents sex-different associations among RLP-C, NAFLD, and cardiometabolic risk factors, and whether RLP-C is associated with NAFLD beyond traditional cardiometabolic risk factors. METHODS: Adolescents in the Raine Study had anthropometry, clinical, biochemistry and arterial stiffness measurements recorded at 17 years of age. Fatty liver, subcutaneous and visceral adipose thickness were assessed using abdominal ultrasound. Relationships among RLP-C, NAFLD, liver biochemistry, insulin resistance, adipokines, adiposity and arterial stiffness were assessed. RESULTS: NAFLD was diagnosed in 15.1% (19.6% females and 10.7% males) of adolescents. Increasing RLP-C levels were associated with increasing severity of hepatic steatosis and metabolic syndrome. Adolescents with NAFLD and serum RLP-C levels in the highest quartile compared with the lowest quartile, had higher serum leptin, homeostatic model assessment of insulin resistance (HOMA-IR), high-sensitivity C-reactive protein, low-density-lipoprotein cholesterol, triglycerides, BMI, subcutaneous and visceral adipose thickness, systolic blood pressure and arterial stiffness, but lower adiponectin and high-density-lipoprotein cholesterol. Using multivariable logistic regression, RLP-C in the lowest quartile compared with the highest quartile was associated with 85% lower odds of NAFLD in males and 55% in females, after adjusting for waist circumference, leptin, ALT, adiponectin and HOMA-IR. CONCLUSIONS: There is an association between RLP-C and NAFLD beyond traditional risk factors of adiposity and insulin resistance in adolescents. Although raised serum RLP-C levels were associated with the severity of hepatic steatosis and markers of cardiometabolic risk, lower serum RLP-C might reflect reduced cardiovascular risk. LAY SUMMARY: Remnant lipoprotein cholesterol (RLP-C) is a part of the blood cholesterol that is linked with heart disease and non-alcoholic fatty liver disease (NAFLD) in adults. In the Raine Study, teenagers with high RLP-C levels had more severe fat accumulation in their liver. Thus, RLP-C might be the hidden link between NAFLD and future risk of heart disease.