Plasma triglycerides and type III hyperlipidemia are independently associated with premature familial coronary artery disease

What Causes Premature Coronary Artery Disease?

PURPOSE OF REVIEW

This review provides an overview of genetic and non-genetic causes of premature coronary artery disease (pCAD).

RECENT FINDINGS

pCAD refers to coronary artery disease (CAD) occurring before the age of 65 years in women and 55 years in men. Both genetic and non-genetic risk factors may contribute to the onset of pCAD. Recent advances in the genetic epidemiology of pCAD have revealed the importance of both monogenic and polygenic contributions to pCAD. Familial hypercholesterolemia (FH) is the most common monogenic disorder associated with atherosclerotic pCAD. However, clinical overreliance on monogenic genes can result in overlooked genetic causes of pCAD, especially polygenic contributions. Non-genetic factors, notably smoking and drug use, are also important contributors to pCAD. Cigarette smoking has been observed in 25.5% of pCAD patients relative to 12.2% of non-pCAD patients. Finally, myocardial infarction (MI) associated with spontaneous coronary artery dissection (SCAD) may result in similar clinical presentations as atherosclerotic pCAD. Recognizing the genetic and non-genetic causes underlying pCAD is important for appropriate prevention and treatment. Despite recent progress, pCAD remains incompletely understood, highlighting the need for both awareness and research.

Remnant cholesterol as a risk factor for all-cause and cardiovascular mortality in incident peritoneal dialysis patients

BACKGROUND AND AIMS

Remnant cholesterol (RC) adversely contributes to cardiovascular disease (CVD) and overall survival in various diseases. However, its role in CVD outcomes and all-cause mortality in patients undergoing peritoneal dialysis (PD) is limited. Therefore, we aimed to investigate the association between RC and all-cause and CVD mortality in patients undergoing PD.

METHODS AND RESULTS

Based on lipid profiles recorded using standard laboratory procedures, fasting RC levels were calculated in 2710 incident patients undergoing PD who were enrolled between January 2006 and December 2017 and followed up until December 2018. Patients were divided into four groups according to the quartile distribution of baseline RC levels (Q1: <0.40 mmol/L, Q2: 0.40 to <0.64 mmol/L, Q3: 0.64 to <1.03 mmol/L, and Q4: ≥1.03 mmol/L). Associations between RC and CVD and all-cause mortality were evaluated using multivariable Cox models. During the median follow-up period of 35.4 months (interquartile range, 20.9-57.2 months), 820 deaths were recorded, of which 438 were CVD-related. Smoothing plots showed non-linear relationships between RC and adverse outcomes. The risks of all-cause and CVD mortality increased progressively through the quartiles (log-rank, p < 0.001). Using adjusted proportional hazard models, a comparison of the highest (Q4) to lowest (Q1) quartiles revealed significant increases in the hazard ratio (HR) for all-cause mortality (HR 1.95 [95% confidence interval (CI), 1.51-2.51]) and CVD mortality risk (HR 2.60 [95% CI, 1.80-3.75]).

CONCLUSION

An increased RC level was independently associated with all-cause and CVD mortality in patients undergoing PD, suggesting that RC was important clinically and required further research.

Effect of evolocumab on fasting and post fat load lipids and lipoproteins in familial dysbetalipoproteinemia

BACKGROUND

Familial dysbetalipoproteinemia (FD) is the second most common monogenic lipid disorder (prevalence 1 in 850-3500), characterized by postprandial remnant accumulation and associated with increased cardiovascular disease (CVD) risk. Many FD patients do not achieve non-HDL-C treatment goals, indicating the need for additional lipid-lowering treatment options.

OBJECTIVES

To evaluate the effect of the PCSK9 monoclonal antibody evolocumab added to standard lipid-lowering therapy on fasting and post fat load lipids and lipoproteins in patients with FD.

METHODS

A randomized placebo-controlled double-blind crossover trial comparing evolocumab (140 mg subcutaneous every 2 weeks) with placebo during two 12-week treatment periods. At the start and end of each treatment period patients received an oral fat load. The primary endpoint was the 8-hour post fat load non-HDL-C area under the curve (AUC). Secondary endpoints included fasting and post fat load lipids and lipoproteins.

RESULTS

In total, 28 patients completed the study. Mean age was 62±9 years and 93% had an Ɛ2Ɛ2 genotype. Evolocumab reduced the 8-hour post fat load non-HDL-C AUC with 49% (95%CI 42-55) and apolipoprotein B (apoB) AUC with 47% (95%CI 41-53). Other fasting and absolute post fat load lipids and lipoproteins including triglycerides and remnant-cholesterol were also significantly reduced by evolocumab. However, evolocumab did not have significant effects on the rise above fasting levels that occurred after consumption of the oral fat load.

CONCLUSIONS

Evolocumab added to standard lipid-lowering therapy significantly reduced fasting and absolute post fat load concentrations of non-HDL-C, apoB and other atherogenic lipids and lipoproteins in FD patients. The clinically significant decrease in lipids and lipoproteins can be expected to translate into a reduction in CVD risk in these high-risk patients.

Signature pattern of gene expression and signaling pathway in premature diabetic patients uncover their correlation to early age coronary heart disease

BACKGROUND

Coronary Heart Disease (CHD) is the leading cause of death in industrialized countries. There is currently no direct relation between CHD and type 2 diabetes mellitus (T2D), one of the major modifiable risk factors for CHD. This study was carried out for genes expression profiling of T2D associated genes to identify related biological processes/es and modulated signaling pathway/s of male subjects with CHD.

METHOD

the subjects were divided into four groups based on their disease, including control, type 2 diabetes mellitus (T2D), CHD, and CHD + T2D groups. The RNA was extracted from their blood, and RT² Profiler™ PCR Array was utilized to determine gene profiling between groups. Finally, the PCR Array results were validated by using Q-RT-PCR in a more extensive and independent population.

RESULT

PCR Array results revealed that the T2D and T2D + CHD groups shared 11 genes significantly up-regulated in both groups. Further analysis showed that the mRNA levels of AKT2, IL12B, IL6, IRS1, IRS2, MAPK14, and NFKB1 increased. Consequently, the mRNA levels of AQP2, FOXP3, G6PD, and PIK3R1 declined in the T2D + CHD group compared to the T2D group. Furthermore, in silico analysis indicated 36 Gene Ontology terms and 59 signaling pathways were significantly enriched in both groups, which may be a culprit in susceptibility of diabetic patients to CHD development.

CONCLUSION

Finally, the results revealed six genes as a hub gene in altering various biological processes and signaling pathways. The expression trend of these identified genes might be used as potential markers and diagnostic tools for the early identification of the vulnerability of T2D patients to develop premature CHD.

Identification of Dysbetalipoproteinemia by an Enhanced Sampson-NIH Equation for Very Low-Density Lipoprotein-Cholesterol

Dysbetalipoproteinemia (hyperlipoproteinemia type III, HLP3) is a genetic disorder that results in the accumulation of cholesterol on highly atherogenic remnant particles. Traditionally, the diagnosis of HLP3 depended upon lipoprotein gel electrophoresis or density gradient ultracentrifugation. Because these two methods are not performed by most clinical laboratories, we describe here two new equations for estimating the cholesterol content of VLDL (VLDL-C), which can then be used for the diagnosis of HLP3. Using results from the beta-quantification (BQ) reference method on a large cohort of dyslipidemic patients (N = 24,713), we identified 115 patients with HLP3 based on having a VLDL-C to plasma TG ratio greater than 0.3 and plasma TG between 150 and 1,000 mg/dl. Next, we developed two new methods for identifying HLP3 and compared them to BQ and a previously described dual lipid apoB ratio method. The first method uses results from the standard lipid panel and the Sampson-NIH equation 1 for estimating VLDL-C (S-VLDL-C), which is then divided by plasma TG to calculate the VLDL-C/TG ratio. The second method is similar, but the Sampson-NIH equation 1 is modified or enhanced (eS-VLDL-C) by including apoB as an independent variable for predicting VLDL-C. At a cut-point of 0.194, the first method showed a modest ability for identifying HLP3 (sensitivity = 73.9%; specificity = 82.6%; and area under the curve (AUC) = 0.8685) but was comparable to the existing dual lipid apoB ratio method. The second method based on eS-VLDL-C showed much better sensitivity (96.5%) and specificity (94.5%) at a cut-point of 0.209. It also had an excellent AUC score of 0.9912 and was superior to the two other methods in test classification. In summary, we describe two new methods for the diagnosis of HLP3. The first one just utilizes the results of the standard lipid panel and the Sampson-NIH equation 1 for estimating (VLDL-C) (S-VLDL-C) and can potentially be used as a screening test. The second method (eS-VLDL-C), in which the Sampson-NIH equation 1 is modified to include apoB, is nearly as accurate as the BQ reference method. Because apoB is widely available at most clinical laboratories, the second method should improve both the accessibility and the accuracy of the HLP3 diagnosis.

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.

Triglyceride glucose-body mass index in identifying high-risk groups of pre-diabetes

Background

Triglyceride glucose-body mass index (TyG-BMI) has been recommended as an alternative indicator of insulin resistance. However, the association between TyG-BMI and pre-diabetes remains to be elucidated.

Methods

More than 100,000 subjects with normal glucose at baseline received follow-up. The main outcome event of concern was pre-diabetes defined according to the diagnostic criteria recommended by the American Diabetes Association (ADA) in 2018 and the World Health Organization (WHO) in 1999. A Cox proportional hazard regression model was used to evaluate the role of TyG-BMI in identifying people at high risk of pre-diabetes.

Results

At a mean observation period of 3.1 years, the incidence of pre-diabetes in the cohort was 3.70 and 12.31% according to the WHO and ADA diagnostic criteria for pre-diabetes, respectively. The multivariate Cox regression analysis demonstrated that TyG-BMI was independently positively correlated with pre-diabetes, and there was a special population dependence phenomenon. Among them, non-obese people, women and people under 50 years old had a significantly higher risk of TyG-BMI-related pre-diabetes (P-interaction< 0.05).

Conclusions

These findings suggest that a higher TyG-BMI significantly increases an individual’s risk of pre-diabetes, and this risk is significantly higher in women, non-obese individuals, and individuals younger than 50 years of age.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01594-7.

Hypertriglyceridaemia: contemporary management of a neglected cardiovascular risk factor

Hypertriglyceridaemia represents one of the most prevalent lipid abnormalities, however it is often eclipsed by focus on LDL cholesterol and is frequently overlooked by clinicians, despite it being an important cardiovascular risk factor. For most patients, hypertriglyceridaemia arises from a combination of environmental factors and multiple genetic variations with small effects. Even in cases with apparent familial clustering of hypertriglyceridaemia, a monogenetic cause is rarely identified. Common secondary causes include obesity, uncontrolled diabetes, alcohol, and various commonly used drugs. Correction of these factors, along with lifestyle optimisation, should be prioritised prior to commencing medication. The goal of drug treatment is to reduce the risk of cardiovascular disease in those with moderate hypertriglyceridaemia and the risk of pancreatitis in those with severe hypertriglyceridaemia. Recent and ongoing trials demonstrate the important role of triglycerides (TG) in determining residual risk in patients with cardiovascular disease (CVD) already established on statin therapy. Novel and emerging data on omega-3 fatty acids (high-dose icosapent ethyl) and the selective PPAR modulator pemafibrate are eagerly awaited and may provide further clarity for clinicians in determining which patients will benefit from TG lowering and help inform clinical guidelines. There are numerous novel therapies on the horizon that reduce TG by decreasing the activity of proteins that inhibit lipoprotein lipase such as apolipoprotein C-III (including Volanesorsen which was recently approved in Germany) and ANGPTL 3/4 which may offer promise for the future.

Familial dysbetalipoproteinemia: highly atherogenic and underdiagnosed disorder

Familial dysbetalipoproteinemia (FD) is a genetic, highly atherogenic disorder. The penetrance of FD depends on the patient’s lifestyle and concomitant diseases. Despite the fact that FD was described almost half a century ago, it is still insufficiently studied and is extremely rarely diagnosed. In actual clinical practice, physicians do not have clear understanding of clinical course and genetic basis of FD. The aim was to present the most complete, but at the same time a critical review with a modern view on FD. We analyzed Russian and foreign publications from following electronic databases: PubMed, eLIBRARY, Google Scholar. As a result, the phenotypic features and genetic variability of the disease were considered and the main issues of diagnosis and treatment of patients with FD were discussed. The data presented will help the clinician to timely suspect the FD, conduct a full range of investigations and prescribe evidence-based lipid-lowering therapy.

Case Report: Identification of a Novel Homozygous Mutation in GPD1 Gene of a Chinese Child With Transient Infantile Hypertriglyceridemia

Transient infantile hypertriglyceridemia is a rare autosomal recessive disorder characterized by hypertriglyceridemia, hypohepatia, hepatomegaly, hepatic steatosis and fibrosis in infancy. Mutations in GPD1 gene are considered the causative factor but the underlying mechanism of this disorder is still enigmatic. To date, only 24 different GPD1 mutations have been reported in the literature worldwide with transient infantile hypertriglyceridemia or relevant conditions. Here we report a Chinese girl who developed hepatomegaly hepatic steatosis, elevated transaminase and hypertriglyceridemia from the age of 4 months. A novel homozygous variant c.454C>T (p.Q152^*) was found in GPD1 gene by next-generation sequencing. This patient is the 3rd Asian reported with transient infantile hypertriglyceridemia. We summarized the clinical presentations of transient infantile hypertriglyceridemia and also expanded the spectrum of disease-causing mutations in GPD1.

Features of Lipid Metabolism in Humanized ApoE Knockin Rat Models

Apolipoprotein E (ApoE), an essential plasma apolipoprotein, has three isoforms (E2, E3, and E4) in humans. E2 is associated with type III hyperlipoproteinemia. E4 is the major susceptibility gene to Alzheimer’s disease (AD) and coronary heart disease (CHD). We investigated lipid metabolism and atherosclerotic lesions of novel humanized ApoE knockin (hApoE KI) rats in comparison to wide-type (WT) and ApoE knockout (ApoE KO) rats. The hApoE2 rats showed the lowest bodyweight and white fat mass. hApoE2 rats developed higher serum total cholesterol (TC), total triglyceride (TG), and low- and very low density lipoprotein (LDL-C&VLDL-C). ApoE KO rats also exhibited elevated TC and LDL-C&VLDL-C. Only mild atherosclerotic lesions were detected in hApoE2 and ApoE KO aortic roots. Half of the hApoE2 rats developed hepatic nodular cirrhosis. A short period of the Paigen diet (PD) treatment led to the premature death of the hApoE2 and ApoE KO rats. Severe vascular wall thickening of the coronary and pulmonary arteries was observed in 4-month PD-treated hApoE4 rats. In conclusion, hApoE2 rats develop spontaneous hyperlipidemia and might be suitable for studies of lipid metabolism-related diseases. With the PD challenge, hApoE4 KI rats could be a novel model for the analysis of vascular remodeling.

Characterizing a Common CERS2 Polymorphism in a Mouse Model of Metabolic Disease and in Subjects from the Utah CAD Study

CONTEXT

Genome-wide association studies have identified associations between a common single nucleotide polymorphism (SNP; rs267738) in CERS2, a gene that encodes a (dihydro)ceramide synthase that is involved in the biosynthesis of very-long-chain sphingolipids (eg, C20-C26) and indices of metabolic dysfunction (eg, impaired glucose homeostasis). However, the biological consequences of this mutation on enzyme activity and its causal roles in metabolic disease are unresolved.

OBJECTIVE

The studies described herein aimed to characterize the effects of rs267738 on CERS2 enzyme activity, sphingolipid profiles, and metabolic outcomes.

DESIGN

We performed in-depth lipidomic and metabolic characterization of a novel CRISPR knock-in mouse modeling the rs267738 variant. In parallel, we conducted mass spectrometry-based, targeted lipidomics on 567 serum samples collected through the Utah Coronary Artery Disease study, which included 185 patients harboring 1 (n = 163) or both (n = 22) rs267738 alleles.

RESULTS

In-silico analysis of the amino acid substitution within CERS2 caused by the rs267738 mutation suggested that rs267738 is deleterious for enzyme function. Homozygous knock-in mice had reduced liver CERS2 activity and enhanced diet-induced glucose intolerance and hepatic steatosis. However, human serum sphingolipids and a ceramide-based cardiac event risk test 1 score of cardiovascular disease were not significantly affected by rs267738 allele count.

CONCLUSIONS

The rs267738 SNP leads to a partial loss-of-function of CERS2, which worsened metabolic parameters in knock-in mice. However, rs267738 was insufficient to effect changes in serum sphingolipid profiles in subjects from the Utah Coronary Artery Disease Study.

Dysbetalipoproteinemia and other lipid abnormalities related to apo E

Dysbetalipoproteinaemia (or type III hyperlipoproteinaemia) is a severe mixed hyperlipidaemia resulting from the accumulation of remnant chylomicron and VLDL particles in plasma, also called β-VLDL. It is caused by a defect in the recognition by hepatic LDL and lipoprotein receptor-related protein (LRP) of β-VLDL. Mutations in the APOE gene, especially in subjects homozygous for the ɛ2/ɛ2 allele, are responsible for this lack of receptor recognition. Dysbetalipoproteinaemia represents 2-5% of the mixed dyslipidaemias seen in Lipid Units, is highly atherogenic and predisposes to diffuse atheromatosis, either coronary, peripheral vascular, or carotid, so early diagnosis and treatment is necessary. The presence of hypertriglyceridaemia, with non-HDL cholesterol/apolipoprotein B ratios>1.43 (in mg/dL) followed by APOE genotyping is the method of choice in the diagnosis of dysbetalipoproteinaemia. It is a dyslipidaemia that responds well to hygienic-dietary treatment, although the combination of statin and fenofibrate is often necessary to achieve optimal control.

Evaluation of Ischemic Heart Disease Factors in Hemophilia Patients in Khorramabad

BACKGROUND

Evaluation of risk factors associated with coronary artery disease and cardiac health in hemophilia patients is necessary to prevent the onset of ischemic heart disease. In this study, we evaluated the cardiovascular status of hemophilic patients in Lorestan province for the early onset of ischemic heart disease.

METHODS

In this cross-sectional descriptive study, a total of 80 patients presenting severe hemophilia, a detailed questionnaire-based investigation was conducted to analyze the prevalence of cardiovascular risk factors in severe hemophilic patients. In patients with hemophilia, body mass index (BMI), blood pressure, diabetes, LDL, cholesterol and HDL, the risk of cardiovascular death was estimated using a predictive risk predictor algorithm of Europe SCORE.

RESULTS

The mean age of the patients was 25 years, where all the patients were non-diabetic. Echocardiography did not show any wall motion abnormality and changes in the T wave and dysrhythmia were also not seen by ECG. 7 patients had high blood pressure, 11 had abnormal HDL, and 1 had abnormal LDL. In this study, serum LDL and HDL levels were not significantly correlated with age and BMI. Conversely, age and BMI were significantly associated with hypertension. Hypertension was observed in people over the age of 25 years and in overweighed individuals. 78.8% had normal BMI and 21.3% were overweighed. There was no significant correlation between serum LDL, serum HDL, and blood pressure and sex. The levels of abnormal LDL and HDL were higher in men than in women.

CONCLUSION

ECG findings from our study did not report any significant cardiac abnormalities among hemophilic patients. Cardiovascular risk factors were not significantly correlated in these patients.

Phenethyl Isothiocyanate Protects against High Fat/Cholesterol Diet-Induced Obesity and Atherosclerosis in C57BL/6 Mice

This study concerns obesity-related atherosclerosis, hyperlipidemia, and chronic inflammation. We studied the anti-obesity and anti-atherosclerosis effects of phenethyl isothiocyanate (PEITC) and explored their underlying mechanisms. We established an animal model of high fat/cholesterol-induced obesity in C57BL/6 mice fed for 13 weeks. We divided the mice into five groups: control (CON), high fat/cholesterol (HFCD), HFCD with 3 mg/kg/day gallic acid (HFCD + G), and HFCD with PEITC (30 and 75 mg/kg/day; HFCD + P30 and P75). The body weight, total cholesterol, and triglyceride were significantly lower in the HFCD + P75 group than in the HFCD group. Hepatic lipid accumulation and atherosclerotic plaque formation in the aorta were significantly lower in both HFCD + PEITC groups than in the HFCD group, as revealed by hematoxylin and eosin (H&E) staining. To elucidate the mechanism, we identified the expression of genes related to inflammation, reverse cholesterol transport, and lipid accumulation pathway in the liver. The expression levels of peroxisome proliferator activated receptor gamma (PPARγ), liver-X-receptor α (LXR-α), and ATP binding cassette subfamily A member 1 (ABCA1) were increased, while those of scavenger receptor A (SR-A1), cluster of differentiation 36 (CD36), and nuclear factor-kappa B (NF-κB) were decreased in the HFCD + P75 group compared with those in the HFCD group. Moreover, PEITC modulated H3K9 and H3K27 acetylation, H3K4 dimethylation, and H3K27 di-/trimethylation in the HFCD + P75 group. We, therefore, suggest that supplementation with PEITC may be a potential candidate for the treatment and prevention of atherosclerosis and obesity.

Management of hypertriglyceridemia

Hypertriglyceridemia is one of the most common lipid abnormalities encountered in clinical practice. Many monogenic disorders causing severe hypertriglyceridemia have been identified, but in most patients triglyceride elevations result from a combination of multiple genetic variations with small effects and environmental factors. Common secondary causes include obesity, uncontrolled diabetes, alcohol misuse, and various commonly used drugs. Correcting these factors and optimizing lifestyle choices, including dietary modification, is important before starting drug treatment. The goal of drug treatment is to reduce the risk of pancreatitis in patients with severe hypertriglyceridemia and cardiovascular disease in those with moderate hypertriglyceridemia. This review discusses the various genetic and acquired causes of hypertriglyceridemia, as well as current management strategies. Evidence supporting the different drug and non-drug approaches to treating hypertriglyceridemia is examined, and an easy to adopt step-by-step management strategy is presented.

The clinical and laboratory investigation of dysbetalipoproteinemia

Familial dysbetalipoproteinemia (type III hyperlipoproteinemia) is a potentially underdiagnosed inherited dyslipidemia associated with greatly increased risk of coronary and peripheral vascular disease. The mixed hyperlipidemia observed in this disorder usually responds well to appropriate medical therapy and lifestyle modification. Although there are characteristic clinical features such as palmar and tuberous xanthomata, associated with dysbetalipoproteinemia, they are not always present, and their absence cannot be used to exclude the disorder. The routine lipid profile cannot distinguish dysbetalipoproteinemia from other causes of mixed hyperlipidemia and so additional investigations are required for confident diagnosis or exclusion. A range of investigations that have been proposed as potential diagnostic tests are discussed in this review, but the definitive biochemical test for dysbetalipoproteinemia is widely considered to be beta quantification. Beta quantification can determine the presence of "β-VLDL" in the supernatant following ultracentrifugation and whether the VLDL cholesterol to triglyceride ratio is elevated. Both features are considered hallmarks of the disease. However, beta quantification and other specialist tests are not widely available and are not high-throughput tests that can practically be applied to all patients with mixed hyperlipidemia. Using apolipoprotein B (as a ratio either to total or non-HDL cholesterol or as part of a multi-step algorithm) as an initial test to select patients for further investigation is a promising approach. Several studies have demonstrated a high degree of diagnostic sensitivity and specificity using these approaches and apolipoprotein B is a relatively low-cost test that is widely available on high-throughput platforms. Genetic testing is also important in the diagnosis, but it should be noted that most individuals with an E₂/₂ genotype do not suffer from remnant hyperlipidemia and around 10% of familial dysbetalipoproteinemia cases are caused by rarer, autosomal dominant mutations in APOE that will only be detected if the gene is fully sequenced. Wider implementation of diagnostic pathways utilizing apo B could lead to more rational use of specialist investigations and more consistent detection of patients with dysbetalipoproteinemia. Without the application of a consistent evidence-based approach to identifying dysbetalipoproteinemia, many cases are likely to remain undiagnosed.

Identification of U-shaped curve relation between proneurotensin and risk of coronary artery disease (CAD) in patients with premature CAD

BACKGROUND AND AIMS

Neurotensin (NT) is a gut hormone with broad effects on the cardiovascular system. Recent data suggested that circulating proneurotensin (pro-NT)-the stable precursor fragment of NT-could independently predict cardiovascular artery disease (CAD) development. However, serum pro-NT levels in patients with premature cardiovascular artery disease (PCAD) are still unknown. This study aims to determine serum pro-NT levels in patients with PCAD and investigate its relationship with PCAD risk.

METHODS AND RESULTS

A total of 490 subjects, including 364 with PCAD and 126 without PCAD (NPCAD), and 182 controls were enrolled in the study. Data of baseline clinical parameters and biochemical variables were collected. Serum pro-NT levels were measured by ELISA. Serum pro-NT levels were higher in patients with PCAD than in controls (59.42 ± 66.66 vs. 38.07 ± 48.48 pg/mL, P < 0.05), especially in patients with BMI<25 kg/m². Serum pro-NT levels were independently related to PCAD (β = 0.349, P < 0.001), and the association revealed a U-shaped curve characteristic between pro-NT tertiles and CAD risk in patients with premature CAD and controls. Subjects with low and high tertiles of pro-NT levels had 1.79-fold and 2.23-fold higher risks of PCAD, respectively, than subjects with median pro-NT levels (P < 0.05). After adjusting for age, gender, and BMI in Model 1 and other confounders in Model 2 and Model 3, the U-shaped relationship remained significant.

CONCLUSION

Serum pro-NT levels were significantly increased in patients with PCAD. The association between pro-NT levels and PCAD risk presents a U-shaped curve characteristic, which demonstrated that subjects with lower and higher pro-NT levels both were more likely to have PCAD.

Machine learning reveals serum sphingolipids as cholesterol-independent biomarkers of coronary artery disease

BACKGROUNDCeramides are sphingolipids that play causative roles in diabetes and heart disease, with their serum levels measured clinically as biomarkers of cardiovascular disease (CVD).METHODSWe performed targeted lipidomics on serum samples from individuals with familial coronary artery disease (CAD) (n = 462) and population-based controls (n = 212) to explore the relationship between serum sphingolipids and CAD, using unbiased machine learning to identify sphingolipid species positively associated with CAD.RESULTSNearly every sphingolipid measured (n = 30 of 32) was significantly elevated in subjects with CAD compared with measurements in population controls. We generated a novel sphingolipid-inclusive CAD risk score, termed SIC, that demarcates patients with CAD independently and more effectively than conventional clinical CVD biomarkers including serum LDL cholesterol and triglycerides. This new metric comprises several minor lipids that likely serve as measures of flux through the ceramide biosynthesis pathway rather than the abundant deleterious ceramide species that are included in other ceramide-based scores.CONCLUSIONThis study validates serum ceramides as candidate biomarkers of CVD and suggests that comprehensive sphingolipid panels should be considered as measures of CVD.FUNDINGThe NIH (DK112826, DK108833, DK115824, DK116888, and DK116450); the Juvenile Diabetes Research Foundation (JDRF 3-SRA-2019-768-A-B); the American Diabetes Association; the American Heart Association; the Margolis Foundation; the National Cancer Institute, NIH (5R00CA218694-03); and the Huntsman Cancer Institute Cancer Center Support Grant (P30CA040214).

Triglycerides, hypertension, and smoking predict cardiovascular disease in dysbetalipoproteinemia

BACKGROUND

Dysbetalipoproteinemia (DBL) is an autosomal recessive lipid disorder associated with a reduced clearance of remnant lipoproteins and is associated with an increased cardiovascular disease (CVD) risk. The genetic cause of DBL is apoE2 homozygosity in 90% of cases. However, a second metabolic hit must be present to precipitate the disease. However, no study has investigated the predictors of CVD, peripheral artery disease and coronary artery disease in a large cohort of patients with DBL.

OBJECTIVE

The objectives of this study were to describe the clinical characteristics of a DBL cohort and to identify the predictors of CVD, peripheral artery disease, and coronary artery disease in this population.

METHODS

The inclusion criteria included age ≥ 18 years, apoE2/E2, triglycerides (TG) > 135 mg/dL and VLDL-C/plasma TG ratio > 0.30.

RESULTS

We studied 221 adult DBL patients, of which 51 (23%) had a history of CVD. We identified 3 independent predictors of CVD, namely hypertension (OR 5.68, 95% CI 2.13-15.16, P = .001), pack year of smoking (OR 1.03, 95% CI 1.01-1.05, P = .01) and TG tertile (OR 1.82, 95% CI 1.09-3.05, P = .02). The CVD prevalence was 51% in patients with hypertension and 18% in those without hypertension (P = .00001), and 30% in the highest TG tertile vs 15% in the lowest tertile (P = .04). Similarly, the CVD prevalence was higher in heavy smokers compared with nonsmokers (36% vs 13%, P = .006).

CONCLUSION

Hypertension, smoking, and TG are independently associated with CVD risk in patients with DBL. Aggressive treatment should be initiated in patients with DBL because of the increased risk of CVD.

Effect of supplementation with omega-3 fatty acids on hypertriglyceridemia in pediatric patients with obesity

Background The beneficial effects of treating hypertriglyceridemic adults with omega-3 fatty acids have been reported. However, information regarding omega-3 treatment of pediatric patients is limited. To evaluate the efficacy and safety of administering omega-3 fatty acids (3 g/day for 12 weeks) to children/adolescents with obesity and hypertriglyceridemia. Methods A randomized, double-blind, placebo-controlled, parallel study involving pediatric patients (10-16 years old) with obesity and hypertriglyceridemia was conducted. The National Center for Health Statistics (CDC) defines obesity as a body mass index (BMI) ≥95th percentile. Subjects with triglyceride concentrations ranging from 150 to 1000 mg/dL were randomized into two groups: those receiving omega-3 fatty acids (eicosapentaenoic and docosahexaenoic acids) (n = 65) and those receiving a placebo (n = 65) for 12 weeks. Serum triglyceride concentrations were always measured from 8 to 9 am after a 12-h fast. Results By the end of treatment, triglyceride concentrations had decreased by 39.1% in the omega-3 group and 14.6% in the placebo group (p < 0.01). The incidence of adverse gastrointestinal events (e.g. flatulence, belching) was 41.2% and 6.2% in the omega-3 and placebo groups, respectively (p < 0.01). There were no serious drug-related adverse events. Conclusions Supplementation with 3 g/day of omega-3 fatty acids is a safe and effective option for treating hypertriglyceridemia in children and adolescents with obesity.

Success in Achieving the Targets of the 20-Year Infancy-Onset Dietary Intervention: Association With Insulin Sensitivity and Serum Lipids

OBJECTIVE

We examined whether success in achieving the key targets of an infancy-onset 20-year dietary intervention associated with insulin sensitivity and serum lipids from early childhood to young adulthood.

RESEARCH DESIGN AND METHODS

The sample comprised 941 children participating in the prospective, randomized Special Turku Coronary Risk Factor Intervention Project (STRIP). Dietary counseling was given biannually based on the Nordic Nutrition Recommendations with the main aim to improve the quality of dietary fat in children's diets and the secondary aim to promote intake of vegetables, fruits, and whole-grain products. Food records and serum lipid profile were studied annually from 1 to 20 years of age, and HOMA of insulin resistance (HOMA-IR) was assessed between 7 and 20 years of age. Meeting the intervention targets for quality of dietary fat was defined as the ratio of saturated fatty acids (SAFA) to monounsaturated and polyunsaturated fatty acids (MUFA + PUFA) <1:2 and intake of SAFA <10% of total energy intake (E%). Meeting the target for intake of whole-grain products, fruits, and vegetables was indicated by a fiber intake ≥3 g/MJ.

RESULTS

Participants in the intervention group had a higher probability of meeting the targets of SAFA/(PUFA + MUFA) <1:2 (risk ratio [RR] 3.91 [95% CI 3.33-4.61]), intake of SAFA <10 E% (RR 3.33 [95% CI 2.99-3.96]), and intake of fiber >3 g/MJ (RR 1.37 [95% CI 1.04-1.80]). Participants who achieved more targets had lower HOMA-IR, lower concentrations of fasting serum glucose, insulin, LDL cholesterol, and non-HDL cholesterol, and a lower ratio of apolipoprotein (Apo) B/ApoA1 (P values all ≤0.003).

CONCLUSIONS

Achieving the key targets of an infancy-onset 20-year dietary intervention was associated with better insulin sensitivity and serum lipid profile throughout the early life course.

The spectrum of type III hyperlipoproteinemia

BACKGROUND

Type III hyperlipoproteinemia is a highly atherogenic dyslipoproteinemia characterized by hypercholesterolemia and hypertriglyceridemia due to markedly increased numbers of cholesterol-enriched chylomicron and very-low-density lipoprotein (VLDL) remnant lipoprotein particles. Type III can be distinguished from mixed hyperlipidemia based on a simple diagnostic algorithm, which involves total cholesterol, triglycerides, and apolipoprotein B (apoB). However, apoB is not measured routinely.

OBJECTIVE

The objective of the present study was to determine if patients with type III could be distinguished from mixed hyperlipidemia based on lipoprotein lipids.

METHODS

Classification was based first on total cholesterol and triglyceride and then on the apoB diagnostic algorithm using apoB plus total cholesterol plus triglycerides, and validated by sequential ultracentrifugation. Four hundred and forty normals, 637 patients with hypertriglyceridemia, and 714 with hypertriglyceridemia and hypercholesterolemia were studied. Plasma lipoproteins were separated by sequential ultracentrifugation and heparin-manganese precipitation. Cholesterol, triglyceride, and apoB were measured in plasma and isolated lipoprotein fractions.

RESULTS

Of the 1351 patients with hypertriglyceridemia, 49 had type III hyperlipoproteinemia, as diagnosed by the apoB algorithm and validated by ultracentrifugation. Plasma triglycerides were higher in the type III subjects: 4.16 mmol/L (3.35-6.08, 25th-75th percentile), but there was considerable overlap with the hypertriglyceridemic subjects 2.65 mmol/L (1.91-4.20, 25th-75th percentile) and the combined hyperlipidemic subjects 3.02 mmol/L (2.07-5.32, 25th-75th percentile). Similarly, total cholesterol was 4.79 mmol/L (4.31-5.58, 25th-75th percentile) for type III vs 5.5 mmol/L (4.64-5.78, 25th-75th percentile) and 7.02 mmol/L (6.39-7.96, 25th-75th percentile), respectively. By contrast, as identified by the apoB algorithm, the VLDL-C/TG, VLDL-C/VLDL-TG, VLDL-C/VLDL apoB, and VLDL apoB/LDL apoB ratios were all higher in type III than in the other hypertriglyceridemic dyslipoproteinemias with the exception of type V as diagnosed by the apoB algorithm.

CONCLUSION

Cholesterol and triglycerides cannot reliably distinguish type III hyperlipoproteinemia from mixed hyperlipidemia. Adding apoB and applying the apoB algorithm makes reliable diagnosis possible and easy. However, unless apoB is introduced into routine clinical care, type III hyperlipoproteinemia will often not be recognized. Given the cardiovascular risk associated with type III and its responsiveness to treatment, this should not be acceptable.

Dyslipidemias in clinical practice

Most dyslipidemic conditions have been linked to an increased risk of cardiovascular disease. Over the past few years major advances have been made regarding the genetic and metabolic basis of dyslipidemias. Detailed characterization of the genetic basis of familial lipid disorders and knowledge concerning the effects of environmental factors on the expression of dyslipidemias have increased substantially, contributing to a better diagnosis in individual patients. In addition to these developments, therapeutic options to lower cholesterol levels in clinical practice have expanded even further in patients with familial hypercholesterolemia and in subjects with cardiovascular disease. Finally, promising upcoming therapeutic lipid lowering strategies will be reviewed. All these advances will be discussed in relation to current clinical practice with special focus on common lipid disorders including familial dyslipidemias.

A novel homozygous mutation in the glycerol-3-phosphate dehydrogenase 1 gene in a Chinese patient with transient infantile hypertriglyceridemia: a case report

Background

Transient infantile hypertriglyceridemia (HTGTI) is an autosomal recessive disorder caused by mutations in the glycerol-3-phosphate dehydrogenase 1 (GPD1) gene.

Case presentation

We report a case of HTGTI in a Chinese female infant. She presented with hepatomegaly, hypertriglyceridemia, moderately elevated transaminases, and hepatic steatosis at 3.5 months of age. A novel mutation c.523C>T, p. (Q175*) was identified in GPD1. The patient was a homozygote and her parents were heterozygous for the mutation. Ultrastructural study showed intrahepatocytic lipid droplets.

Conclusions

This is the first reported case of HTGTI in Chinese, expanding the worldwide distribution of HTGTI and the mutation spectrum of GPD1.

Electronic supplementary material

The online version of this article (10.1186/s12876-018-0827-6) contains supplementary material, which is available to authorized users.

Approach to Hypertriglyceridemia in the Pediatric Population

Hypertriglyceridemia is increasingly identified in children and adolescents, owing to improved screening and higher prevalence of childhood obesity. Hypertriglyceridemia can result from either increased triglyceride (TG) production or reduced TG clearance. The etiologic origin can be primary (genetic) or secondary, but it is often multifactorial. Management is challenging because of the interplay of genetic and secondary causes and lack of evidence-based guidelines. Lifestyle changes and dietary interventions are most important, especially in hypertriglyceridemia associated with obesity. Dietary restriction of fat remains the mainstay of management in primary hypertriglyceridemia. When fasting TG concentration is increased above 500 mg/dL (5.65 mmol/L), fibrates may be used to prevent pancreatitis. Omega-3 fatty acids are often used as an adjunctive therapy. When the fasting TG concentration is less than 500 mg/dL (5.65 mmol/L) and if the non-high-density lipoprotein cholesterol level is above 145 mg/dL (3.76 mmol/L), statin treatment can be considered.

The application of atherogenic dyslipidaemia consensus recommendations in the primary care setting. DAT-AP study

BACKGROUND AND AIMS

The "DAT-AP" (from the Spanish, "Dislipemia ATerogénica en Atención Primaria", for Atherogenic Dyslipidaemia in Primary Care) study objective is to determine to what extent published consensus guidelines for the diagnostic and therapeutic management of AD are used in the primary care setting, and to evaluate the approach of the participating physicians towards the detection, diagnosis, and treatment of AD.

METHODS

This is descriptive, cross-sectional, multicentre study performed between January and May 2015 in primary care centres throughout Spain. Study data were collected in 2 independent blocks, the first addressing theoretical aspects of AD and the second, practical aspects (clinical cases) RESULTS: The theoretical part is in the process of publication. This manuscript depicts the clinical cases block. Although study participants showed good knowledge of the subject, the high prevalence of this disease requires an additional effort to optimise detection and treatment, with the implementation of appropriate lifestyle interventions and the prescription of the best treatment.

Familial dysbetalipoproteinemia: an underdiagnosed lipid disorder

PURPOSE OF REVIEW

To review pathophysiological, epidemiological and clinical aspects of familial dysbetalipoproteinemia; a model disease for remnant metabolism and remnant-associated cardiovascular risk.

RECENT FINDINGS

Familial dysbetalipoproteinemia is characterized by remnant accumulation caused by impaired remnant clearance, and premature cardiovascular disease. Most familial dysbetalipoproteinemia patients are homozygous for apolipoprotein ε2, which is associated with decreased binding of apolipoprotein E to the LDL receptor. Although familial dysbetalipoproteinemia is an autosomal recessive disease in most cases, 10% is caused by autosomal dominant mutations. Of people with an ε2ε2 genotype 15% develops familial dysbetalipoproteinemia, which is associated with secondary risk factors, such as obesity and insulin resistance, that inhibit remnant clearance by degradation of the heparan sulfate proteoglycan receptor. The prevalence of familial dysbetalipoproteinemia ranges from 0.12 to 0.40% depending on the definition used. Clinical characteristics of familial dysbetalipoproteinemia are xanthomas and mixed hyperlipidemia (high total cholesterol and triglycerides); the primary lipid treatment goal in familial dysbetalipoproteinemia is non-HDL-cholesterol; and treatment consists of dietary therapy and treatment with statin and fibrate combination.

SUMMARY

Familial dysbetalipoproteinemia is a relatively common, though often not diagnosed, lipid disorder characterized by mixed hyperlipidemia, remnant accumulation and premature cardiovascular disease, which should be treated with dietary therapy and statin and fibrate combination.

Shorter telomere length in Europeans than in Africans due to polygenetic adaptation

Leukocyte telomere length (LTL), which reflects telomere length in other somatic tissues, is a complex genetic trait. Eleven SNPs have been shown in genome-wide association studies to be associated with LTL at a genome-wide level of significance within cohorts of European ancestry. It has been observed that LTL is longer in African Americans than in Europeans. The underlying reason for this difference is unknown. Here we show that LTL is significantly longer in sub-Saharan Africans than in both Europeans and African Americans. Based on the 11 LTL-associated alleles and genetic data in phase 3 of the 1000 Genomes Project, we show that the shifts in allele frequency within Europe and between Europe and Africa do not fit the pattern expected by neutral genetic drift. Our findings suggest that differences in LTL within Europeans and between Europeans and Africans is influenced by polygenic adaptation and that differences in LTL between Europeans and Africans might explain, in part, ethnic differences in risks for human diseases that have been linked to LTL.

Management of Hypertriglyceridemia for Prevention of Atherosclerotic Cardiovascular Disease

Mendelian randomization data strongly suggest that hypertriglyceridemia (HTG) causes atherosclerotic cardiovascular disease (ASCVD), and so triglyceride (TG) level-lowering treatment in HTG is now more strongly recommended to address the residual ASCVD risk than has been the case in (generally earlier) published guidelines. Fibrates are the best-established agents for TG level lowering and are generally used as first-line treatment of TG levels greater than 500 mg/dL. Statins are the best-established agents for ASCVD prevention, and so are usually used as first-line treatment of TG levels less than 500 mg/dL.

A comparative study of four independent methods to measure LDL particle concentration

BACKGROUND

Low-density lipoprotein particle concentration (LDL-P) is generally more predictive of clinical cardiovascular endpoints than LDL cholesterol (LDL-C). Few studies have directly compared multiple LDL-P methods, particularly with ultracentrifugation.

OBJECTIVE

Examine comparability and precision of 4 LDL-P methods.

METHODS

We divided serum from 48 subjects into blinded triplicates and measured LDL-P in 3 separate laboratories by 4 methods: ultracentrifugation (reference method), a novel electrophoretic method, and nuclear magnetic resonance spectroscopy (NMR) by 2 independent methods: a 400 MHz Vantera(®) instrument supplied by Liposcience (LS-NMR) and operated at ARUP Laboratories, and a 600 MHz Bruker instrument (ASCEND 600) operated at Health Diagnostic Laboratory (HD-NMR).

RESULTS

Of the 4 methods, ultracentrifugation was the most precise and LS-NMR the least; the latter had a significantly greater CV (p < 0.0001) as compared with all 3 of the other methods, although all CVs were clinically acceptable. The electrophoretic method showed similar precision to ultracentrifugation, while HD-NMR was intermediate. The HD-NMR had the slope closest to 1 (0.90, 95% CI 0.71 to 1.09) and the intercept closest to 0 (-48, -353 to 256) compared to the ultracentrifugation method in Deming regression models. While the two NMR methods correlated well (r = 0.95) with each other and had a slope equivalent to 1 (1.08, 0.98 to 1.19), their intercept in Deming regression excluded 0 (194, 53 to 335) indicating a vertical shift between the two methods.

CONCLUSIONS

This LDL-P method comparison may prove useful for future research and clinical applications.

Study of Five Pubertal Transition-Related Gene Polymorphisms as Risk Factors for Premature Coronary Artery Disease in a Chinese Han Population

Background

Recently, single nucleotide polymorphisms (SNPs) (DLK-rs10144321, SIX6-rs1254337, MKRN3-rs12148769, LIN28B-rs7759938, and KCNK9-rs1469039) were found to be strongly associated with age at menarche. Recent studies also suggested that age at menarche is a heritable trait and is associated with risks for obesity, type 2 diabetes mellitus (T2DM), cardiovascular disease, and all-cause mortality. Since an association between these five SNPs and premature coronary artery disease (CAD) has never been reported, we investigated whether these SNPs are associated with premature CAD and its severity in a Chinese Han population.

Methods

We enrolled 432 consecutive patients including 198 with premature CAD (<55 years in men and <65 years in women) and 234 controls. All subjects were genotyped for the five SNPs by the PCR-ligase detection reaction method. The associations between these SNPs and premature CAD and its severity were analyzed.

Results

The following genotypes were identified: GG, AG, and AA at rs10144321 and rs12148769; TT, AT, and AA at rs1254337; CC, CT, and TT at rs1469039; and TT and CT at rs7759938. Significant differences in genotype distribution frequencies at rs1254337 were found between controls and patients with premature CAD (P<0.05). No associations were found between the five SNPs and the severity of coronary lesions (all P>0.05). Compared with controls, patients with premature CAD had a higher prevalence of T2DM and dyslipidemia, and the proportion of patients with T2DM rose significantly with an increase in the number of stenosed coronary vessels (all P<0.05). After adjustment for the clinical parameters in multivariable analysis, three factors were identified that significantly increased the risk of premature CAD: the AA genotype at rs1254337 (OR: 2.388, 95% CI: 1.190–4.792, P = 0.014), male gender (OR: 1.565, 95% CI: 1.012–2.420, P = 0.044), and T2DM (OR 2.252, 95% CI: 1.233–4.348, P = 0.015).

Conclusions

Among the five pubertal transition-related gene polymorphisms, we identified an association between rs1254337 and premature CAD in a Chinese Han population.

Hyperlipoproteinemia type 3: the forgotten phenotype

Hyperlipoproteinemia type 3 (HLP3) is caused by impaired removal of triglyceride-rich lipoproteins (TGRL) leading to accumulation of TGRL remnants with abnormal composition. High levels of these remnants, called β-VLDL, promote lipid deposition in tuberous xanthomas, atherosclerosis, premature coronary artery disease, and early myocardial infarction. Recent genetic and molecular studies suggest more genes than previously appreciated may contribute to the expression of HLP3, both through impaired hepatic TGRL processing or removal and increased TGRL production. HLP3 is often highly amenable to appropriate treatment. Nevertheless, most HLP3 probably goes undiagnosed, in part because of lack of awareness of the relatively high prevalence (about 0.2% in women and 0.4-0.5% in men older than 20 years) and largely because of infrequent use of definitive diagnostic methods.

Dysbetalipoproteinemia: Two cases report and a diagnostic algorithm

Dysbetalipoproteinemia is a rare familial dyslipidemia characterized by approximately equally elevated serum cholesterol and triglyceride levels due to accumulated remnant lipoproteins in apolipoprotein E2/E2 homozygotes. It is associated with an increased risk for premature cardiovascular disease. Thus, making a diagnosis of dysbetalipoproteinemia aids in assessing cardiovascular risk correctly and allows for genetic counseling. However, the diagnostic work-up can be challenging. Diagnosis of dysbetalipoproteinemia should be considered in patients mixed dyslipidemia when the apolipoprotein B concentration is relatively low in relation to the total cholesterol concentration or when there is significant disparity between the calculated low density lipoprotein (LDL) and directly measured LDL cholesterol concentrations. Other indices are also informative in the diagnostic process. We present herein two phenotypically different cases (a 44-year-old man with severe hypertriglyceridemia and a 49-year-old woman with mixed dyslipidemia) of genotypically proven familial dysbetalipoproteinemia and a diagnostic algorithm of the disease.

Effectiveness of omega-3 polysaturated fatty acids (fish oil) supplementation for treating hypertriglyceridemia in children and adolescents

Limited pharmacological options are available for management pediatric hypertriglyceridemia. We examined the effectiveness of dietary fish oil supplementation as a means to reduce triglyceride levels in pediatric patients. We reviewed 111 children aged 8 to 18 years with hypertriglyceridemia (≥1.5 mmol/L) undergoing treatment in a specialized dyslipidemia clinic. At the treating cardiologist's discretion, 60 subjects received nonprescription fish oil supplementation (500-1000 mg/d), while the remaining patients did not. Initially there were no baseline differences between groups, including the use of concomitant lipid-lowering medication. Treatment with fish oil was associated with a potential clinically relevant but non-statistically significant decrease in triglycerides and triglyceride-to-high-density lipoprotein (HDL) ratio. Fish oil had no effect on HDL-cholesterol, non-HDL-cholesterol, or total cholesterol. All associations remained unchanged when adjusted for body mass index z score, nutrition, physical activity, and screen time. Fish oil supplementation was not significantly effective in treating hypertriglyceridemia in pediatric patients.

Atherogenic Dyslipidemia and Residual Cardiovascular Risk in Statin-Treated Patients

Background and Purpose—

Treatment with statins reduces the rate of cardiovascular events in high-risk patients, but residual risk persists. At least part of that risk may be attributable to atherogenic dyslipidemia characterized by low high-density lipoprotein cholesterol (≤40 mg/dL) and high triglycerides (triglycerides ≥150 mg/dL).

Methods—

We studied subjects with stroke or transient ischemic attack in the Prevention of Cerebrovascular and Cardiovascular Events of Ischemic Origin With Terutroban in Patients With a History of Ischemic Stroke or Transient Ischemic Attack (PERFORM; n=19 100) and Stroke Prevention by Aggressive Reduction in Cholesterol Levels (SPARCL; n=4731) trials who were treated with a statin and who had high-density lipoprotein cholesterol and triglycerides measurements 3 months after randomization (n=10 498 and 2900, respectively). The primary outcome measure for this exploratory analysis was the occurrence of major cardiovascular events (nonfatal myocardial infarction, nonfatal stroke, or cardiovascular death). We also performed a time-varying analysis to account for all available high-density lipoprotein cholesterol and triglyceride measurements.

Results—

A total of 10% of subjects in PERFORM and 9% in SPARCL had atherogenic dyslipidemia after ≥3 months on start statin therapy. After a follow-up of 2.3 years (PERFORM) and 4.9 years (SPARCL), a major cardiovascular event occurred in 1123 and 485 patients in the 2 trials, respectively. The risk of major cardiovascular events was higher in subjects with versus those without atherogenic dyslipidemia in both PERFORM (hazard ratio, 1.36; 95% confidence interval, 1.14–1.63) and SPARCL (hazard ratio, 1.40; 95% confidence interval, 1.06–1.85). The association was attenuated after multivariable adjustment (hazard ratio, 1.23; 95% confidence interval, 1.03–1.48 in PERFORM and hazard ratio, 1.24; 95% confidence interval, 0.93–1.65 in SPARCL). Time-varying analysis confirmed these findings.

Conclusions—

The presence of atherogenic dyslipidemia was associated with higher residual cardiovascular risk in PERFORM and SPARCL subjects with stroke or transient ischemic attack receiving statin therapy. Specific therapeutic interventions should now be trialed to address this residual risk.

Dysbetalipoproteinaemia: a mixed hyperlipidaemia of remnant lipoproteins due to mutations in apolipoprotein E

Atherosclerosis is strongly associated with dyslipoproteinaemia, and especially with increasing concentrations of low-density lipoprotein and decreasing concentrations of high-density lipoproteins. Its association with increasing concentrations of plasma triglyceride is less clear but, within the mixed hyperlipidaemias, dysbetalipoproteinaemia (Fredrickson type III hyperlipidaemia) has been identified as a very atherogenic entity associated with both premature ischaemic heart disease and peripheral arterial disease. Dysbetalipoproteinaemia is characterized by the accumulation of remnants of chylomicrons and of very low-density lipoproteins. The onset occurs after childhood and usually requires an additional metabolic stressor. In women, onset is typically delayed until menopause. Clinical manifestations may vary from no physical signs to severe cutaneous and tendinous xanthomata, atherosclerosis of coronary and peripheral arteries, and pancreatitis when severe hypertriglyceridaemia is present. Rarely, mutations in apolipoprotein E are associated with lipoprotein glomerulopathy, a condition characterized by progressive proteinuria and renal failure with varying degrees of plasma remnant accumulation. Interestingly, predisposing genetic causes paradoxically result in lower than average cholesterol concentration for most affected persons, but severe dyslipidaemia develops in a minority of patients. The disorder stems from dysfunctional apolipoprotein E in which mutations result in impaired binding to low-density lipoprotein (LDL) receptors and/or heparin sulphate proteoglycans. Apolipoprotein E deficiency may cause a similar phenotype. Making a diagnosis of dysbetalipoproteinaemia aids in assessing cardiovascular risk correctly and allows for genetic counseling. However, the diagnostic work-up may present some challenges. Diagnosis of dysbetalipoproteinaemia should be considered in mixed hyperlipidaemias for which the apolipoprotein B concentration is relatively low in relation to the total cholesterol concentration or when there is significant disparity between the calculated LDL and directly measured LDL cholesterol concentrations. Genetic tests are informative in predicting the risk of developing the disease phenotype and are diagnostic only in the context of hyperlipidaemia. Specialised lipoprotein studies in reference laboratory centres can also assist in diagnosis. Fibrates and statins, or even combination treatment, may be required to control the dyslipidaemia.

Emergent biomarkers of residual cardiovascular risk in patients with low HDL-c and/or high triglycerides and average LDL-c concentrations: focus on HDL subpopulations, Oxidized LDL, adiponectin, and uric acid

This study intended to determine the impact of HDL-c and/or TGs levels on patients with average LDL-c concentration, focusing on lipidic, oxidative, inflammatory, and angiogenic profiles. Patients with cardiovascular risk factors (n = 169) were divided into 4 subgroups, combining normal and low HDL-c with normal and high TGs patients. The following data was analyzed: BP, BMI, waist circumference and serum glucose, Total-c, TGs, LDL-c, oxidized-LDL, total HDL-c and HDL subpopulations, paraoxonase-1 (PON1) activity, hsCRP, uric acid, TNF- α , adiponectin, VEGF, and iCAM1. The two populations with increased TGs levels, regardless of the normal or low HDL-c, presented obesity and higher waist circumference, Total-c, LDL-c, Ox-LDL, and uric acid. Adiponectin concentration was significantly lower and VEGF was higher in the population with cumulative low values of HDL-c and high values of TGs, while HDL quality was reduced in the populations with impaired values of HDL-c and/or TGs, viewed by reduced large and increased small HDL subfractions. In conclusion, in a population with cardiovascular risk factors, low HDL-c and/or high TGs concentrations seem to be associated with a poor cardiometabolic profile, despite average LDL-c levels. This condition, often called residual risk, is better evidenced by using both traditional and nontraditional CV biomarkers, including large and small HDL subfractions, Ox-LDL, adiponectin, VEGF, and uric acid.

Molecular biology of atherosclerosis

At least 468 individual genes have been manipulated by molecular methods to study their effects on the initiation, promotion, and progression of atherosclerosis. Most clinicians and many investigators, even in related disciplines, find many of these genes and the related pathways entirely foreign. Medical schools generally do not attempt to incorporate the relevant molecular biology into their curriculum. A number of key signaling pathways are highly relevant to atherogenesis and are presented to provide a context for the gene manipulations summarized herein. The pathways include the following: the insulin receptor (and other receptor tyrosine kinases); Ras and MAPK activation; TNF-α and related family members leading to activation of NF-κB; effects of reactive oxygen species (ROS) on signaling; endothelial adaptations to flow including G protein-coupled receptor (GPCR) and integrin-related signaling; activation of endothelial and other cells by modified lipoproteins; purinergic signaling; control of leukocyte adhesion to endothelium, migration, and further activation; foam cell formation; and macrophage and vascular smooth muscle cell signaling related to proliferation, efferocytosis, and apoptosis. This review is intended primarily as an introduction to these key signaling pathways. They have become the focus of modern atherosclerosis research and will undoubtedly provide a rich resource for future innovation toward intervention and prevention of the number one cause of death in the modern world.

Association of the level of heteroplasmy of the 15059G>A mutation in the MT-CYB mitochondrial gene with essential hypertension

AIM

To examine whether the heteroplasmy level for 15059G>A mutation in the mitochondrial genome might be associated with essential hypertension.

METHODS

This cross-sectional study involved 196 unrelated participants randomly selected from general population (90 males and 106 females) who underwent a regular medical check-up at the Institute for Atherosclerosis Research (Moscow, Russia). One hundred and twenty of them (61%) had essential hypertension, and 76 (39%) were apparently healthy normotensive persons. The level of heteroplasmy for 15059G>A mutation occurring in the coding region of cytochrome b gene (MT-CYB) of mtDNA isolated from the blood leukocytes, was quantified using DNA pyrosequencing method.

RESULTS

The 15059G>A heteroplasmy level ranged between 4% and 83%, with a median level of 31%. Between the upper and lower quartiles of 15059G>A heteroplasmy distribution, significant differences were observed for patients' age, systolic blood pressure, and triglyceride levels. 15059G>A heteroplasmy correlated both with age (r = 0.331, P < 0.001) and the presence of hypertension (r = 0.228, P = 0.002). Regression analysis revealed that the age explains 12% variability of 15059G>A heteroplasmy, and hypertension independently explains more 5% variability. The 15059G>A heteroplasmy exceeding 31% was found to be significantly associated with a higher risk of essential hypertension (odds ratio 2.76; P (Fisher) 0.019]. The study participants with high 15059G>A heteroplasmy level were found to have significantly higher age (P < 0.001) and the prevalence of essential hypertension (P = 0.033), as compared to those with low 15059G>A heteroplasmy level. These observations suggested a positive correlation between the level of 15059G>A heteroplasmy and essential hypertension.

CONCLUSION

This study provides the evidence of association of mtDNA 15059G>A mutation heteroplasmy with essential hypertension.

Fibrates are an essential part of modern anti-dyslipidemic arsenal: spotlight on atherogenic dyslipidemia and residual risk reduction

Currently the world faces epidemic of several closely related conditions: obesity, metabolic syndrome and type 2 diabetes (T2DM). The lipid profile of these patients and those with metabolic syndrome is characterized by the concurrent presence of qualitative as well as quantitative lipoprotein abnormalities: low levels of HDL, increased triglycerides, and prevalence of LDL particles that are smaller and denser than normal. This lipid phenotype has been defined as atherogenic dyslipidemia. Overwhelming evidences demonstrate that all components of the atherogenic dyslipidemia are important risk-factors for cardiovascular diseases. Optimal reduction of cardiovascular risk through comprehensive management of atherogenic dyslipidemias basically depends of the presence of efficacious lipid-modulating agents (beyond statin-based reduction of LDL-C). The most important class of medications which can be effectively used nowadays to combat atherogenic dyslipidemias is the fibrates. From a clinical point of view, in all available 5 randomized control trials beneficial effects of major fibrates (gemfibrozil, fenofibrate, bezafibrate) were clearly demonstrated and were highly significant in patients with atherogenic dyslipidemia. In these circumstances, the main determinant of the overall results of the trial is mainly dependent of the number of the included appropriate patients with atherogenic dyslipidemia. In a meta-analysis of dyslipidemic subgroups totaling 4726 patients a significant 35% relative risk reduction in cardiovascular events was observed compared with a non significant 6% reduction in those without dyslipidemia. However, different fibrates may have a somewhat different spectrum of effects. Currently only fenofibrate was investigated and proved to be effective in reducing microvascular complications of diabetes. Bezafibrate reduced the severity of intermittent claudication. Cardinal differences between bezafibrate and other fibrates are related to the effects on glucose metabolism and insulin resistance. Bezafibrate is the only clinically available pan - (alpha, beta, gamma) PPAR balanced activator. Bezafibrate decreases blood glucose level, HbA1C, insulin resistance and reduces the incidence of T2DM compared to placebo or other fibrates. Among major fibrates, bezafibrate appears to have the strongest and fenofibrate the weakest effect on HDL-C. Current therapeutic use of statins as monotherapy is still leaving many patients with atherogenic dyslipidemia at high risk for coronary events because even intensive statin therapy does not eliminate the residual cardiovascular risk associated with low HDL and/or high triglycerides. As compared with statin monotherapy (effective mainly on LDL-C levels and plaque stabilization), the association of a statin with a fibrate will also have a major impact on triglycerides, HDL and LDL particle size. Moreover, in the specific case of bezafibrate one could expect neutralizing of the adverse pro-diabetic effect of statins. Though muscle pain and myositis is an issue in statin/fibrate treatment, adverse interaction appears to occur to a significantly greater extent when gemfibrozil is administered. However, bezafibrate and fenofibrate seems to be safer and better tolerated. Combined fibrate/statin therapy is more effective in achieving a comprehensive lipid control and may lead to additional cardiovascular risk reduction, as could be suggested for fenofibrate following ACCORD Lipid study subgroup analysis and for bezafibrate on the basis of one small randomized study and multiple observational data. Therefore, in appropriate patients with atherogenic dyslipidemia fibrates- either as monotherapy or combined with statins - are consistently associated with reduced risk of cardiovascular events. Fibrates currently constitute an indispensable part of the modern anti-dyslipidemic arsenal for patients with atherogenic dyslipidemia.