Influencia de la concentración de triglicéridos en la lipoproteína(a) en función de la dislipidemia / Influence of triglyceride concentration in lipoprotein (a) as a function of dyslipidemia

Introducción Recientemente se ha demostrado una relación inversa entre la concentración en sangre de la lipoproteína(a) (Lp[a]) y los triglicéridos (TG). A mayor tamaño de lipoproteínas de muy baja densidad (VLDL), mayor presencia de VLDL ricas en apoliproteína E (apo E) y en sujetos con genotipo apo E2/E2, Lp(a) más baja. El mecanismo de esta asociación contrapuesta es desconocido. El objetivo de nuestro análisis fue evaluar la correspondencia Lp(a)-TG en los pacientes atendidos en las Unidades de Lípidos incluidos en el registro de la Sociedad Española de Arteriosclerosis (SEA) comparando las diferentes dislipidemias. Pacientes y métodos Se incluyeron 5.275 usuarios de ≥ 18 años registrados antes del 31 de marzo de 2023, con datos de concentración de Lp(a) e información completa del perfil lipídico sin tratamiento. Resultados La media de edad fue de 53,0 ± 14,0 años, con 48% de mujeres. Un total de 9,5% (n = 502) tenían diabetes mellitus (DM) y 1.184 sujetos (22,4%) presentaban obesidad. La mediana de TG fue de 130 mg/dL (rango intercuartílico [IQR] 88,0-210) y de Lp(a) 55,0 nmol/L (IQR 17,9 -156). La concentración de Lp(a) mostró una asociación negativa con la de TG cuando los valores de estos superaban los 300 mg/dL. Los pacientes con TG > 1.000 mg/dL mostraron el menor nivel de Lp(a) 17,9 nmol/L y los usuarios con TG < 300 mg/dL, presentaron una media de Lp(a) de 60,1 nmol/L. En pacientes sin DM ni obesidad, la relación inversa de Lp(a)-TG fue especialmente importante (p < 0,001). La mediana de Lp(a) fue de 58,3 nmol/L en aquellos con TG < 300 mg/dL y 22,0 nmol/L si TG > 1.000 mg/dL. No se encontró asociación entre TG y Lp(a) en sujetos con DM y obesidad, ni en los que contaban con hipercolesterolemia familiar (HF). En los que padecen hiperlipemia combinada multifactorial con TG < 300 mg/dL la Lp(a) fue 64,6 nmol/L, en el rango de 300-399 mg/dL de TG la Lp(a) desciende hasta 38,8 nmol/L y hasta 22,3 nmol/L si TG > 1.000 mg/dL. Conclusiones ... (AU)

Background Recently, an inverse relationship between the blood concentration of lipoprotein(a) (Lp(a)) and triglycerides (TG) has been demonstrated. The larger the VLDL particle size, the greater the presence of VLDL rich in apoliprotein E and in subjects with the apoE2/E2 genotype, the lower Lp(a) concentration. The mechanism of this inverse association is unknown. The objective of this analysis was to evaluate the Lp(a)–TG association in patients treated at the lipid units included in the registry of the Spanish Society of Atherosclerosis (SEA) by comparing the different dyslipidemias. Patients and methods Five thousand two hundred and seventy-five subjects ≥18 years of age registered in the registry before March 31, 2023, with Lp(a) concentration data and complete lipid profile information without treatment were included. Results The mean age was 53.0 ± 14.0 years, with 48% women. The 9.5% of subjects (n = 502) had diabetes and the 22.4% (n = 1184) were obese. The median TG level was 130 mg/dL (IQR 88.0–210) and Lp(a) 55.0 nmol/L (IQR 17.9–156). Lp(a) concentration showed a negative association with TG concentration when TG values exceeded 300 mg/dL. Subjects with TG > 1000 mg/dL showed the lowest level of Lp(a), 17.9 nmol/L, and subjects with TG < 300 mg/dL had a mean Lp(a) concentration of 60.1 nmol/L. In subjects without diabetes or obesity, the inverse association of Lp(a)–TG was especially important (p < 0.001). The median Lp(a) was 58.3 nmol/L in those with TG < 300 mg/dL and 22.0 nmol/L if TG > 1000 mg/dL. No association was found between TG and Lp(a) in subjects with diabetes and obesity, nor in subjects with familial hypercholesterolemia. In subjects with multifactorial combined hyperlipemia with TG < 300 mg/dL, Lp(a) was 64.6 nmol/L; in the range of 300–399 mg/dL of TG, Lp(a) decreased to 38. 8 nmol/L, and up to 22.3 nmol/L when TG > 1000 mg/dL. Conclusions ... (AU)

APOE and familial hypercholesterolemia.

PURPOSE OF REVIEW: Autosomal dominant hypercholesterolemia is a common cause of cardiovascular disease. In addition to the classic genes that cause hypercholesterolemia, LDLR, APOB and PCSK9, a new locus has emerged as a candidate to be the cause of this hyperlipidemia, the p.(Leu167del) mutation in the APOE gene. RECENT FINDINGS: Various studies have demonstrated the involvement of the p.(Leu167del) mutation in the APOE gene in hypercholesterolemia: Studies of family segregation, lipoprotein composition by ultracentrifugation and proteomic techniques, and functional studies of VLDL-carrying p.(Leu167del) internalization with cell cultures have demonstrated the role of this mutation in the cause of hypercholesterolemia. The phenotype of individuals carrying the p.(Leu167del) in APOE is indistinguishable from familial hypercholesterolemia individuals with mutations in the classic genes. However, a better response to lipid-lowering treatment has been demonstrated in these APOE mutation carrier individuals. SUMMARY: Therefore, APOE gene should be considered a candidate locus along with LDLR, APOB, and PCSK9 to be investigated in the genetic diagnosis of familial hypercholesterolemia.

OptiMo-LDLr: An Integrated In Silico Model with Enhanced Predictive Power for LDL Receptor Variants, Unraveling Hot Spot Pathogenic Residues.

Familial hypercholesterolemia (FH) is an inherited metabolic disease affecting cholesterol metabolism, with 90% of cases caused by mutations in the LDL receptor gene (LDLR), primarily missense mutations. This study aims to integrate six commonly used predictive software to create a new model for predicting LDLR mutation pathogenicity and mapping hot spot residues. Six predictive-software are selected: Polyphen-2, SIFT, MutationTaster, REVEL, VARITY, and MLb-LDLr. Software accuracy is tested with the characterized variants annotated in ClinVar and, by bioinformatic and machine learning techniques all models are integrated into a more accurate one. The resulting optimized model presents a specificity of 96.71% and a sensitivity of 98.36%. Hot spot residues with high potential of pathogenicity appear across all domains except for the signal peptide and the O-linked domain. In addition, translating this information into 3D structure of the LDLr highlights potentially pathogenic clusters within the different domains, which may be related to specific biological function. The results of this work provide a powerful tool to classify LDLR pathogenic variants. Moreover, an open-access guide user interface (OptiMo-LDLr) is provided to the scientific community. This study shows that combination of several predictive software results in a more accurate prediction to help clinicians in FH diagnosis.

Factors associated with the presence of tendon xanthomas in familial hypercholesterolemia.

INTRODUCTION AND OBJECTIVES: Tendon xanthomas (TX) are lipid deposits highly specific to familial hypercholesterolemia (FH). However, there is significant variability in their presentation among FH patients, primarily due to largely unknown causes. Lipoprotein(a) is a well-established independent risk factor for atherosclerotic cardiovascular disease in the general population as well as in FH. Given the wide variability of lipoprotein(a) among FH individuals and the likelihood that TX may result from a proatherogenic and proinflammatory condition, the objective of this study was to analyze the size of TX in the Achilles tendons of FH participants and the variables associated with their presence, including lipoprotein(a) concentration. METHODS: A cross-sectional study was conducted on 377 participants with a molecular diagnosis of heterozygous FH. Achilles tendon maximum thickness (ATMT) was measured using ultrasonography with standardized equipment and procedures. Demographic variables and lipid profiles were collected. A multivariate linear regression model using a log-Gaussian approach was used to predict TX size. Classical cardiovascular risk factors and lipoprotein(a) were included as explanatory variables. RESULTS: The mean low-density lipoprotein cholesterol level was 277mg/dL without lipid-lowering treatment, and the median ATMT was 5.50mm. We demonstrated that age, sex, low-density lipoprotein cholesterol, and lipoprotein(a) were independently associated with ATMT. However, these 4 variables did not account for most the interindividual variability observed (R2=0.205). CONCLUSIONS: TX, a characteristic hallmark of FH, exhibit heterogeneity in their presentation. Interindividual variability can partially be explained by age, male sex, low-density lipoprotein cholesterol, and lipoprotein(a) but these factors account for only 20% of this heterogeneity.

Influence of triglyceride concentration in lipoprotein (a) as a function of dyslipidemia. / Influencia de la concentración de triglicéridos en la lipoproteína(a) en función de la dislipidemia.

BACKGROUND: Recently, an inverse relationship between the blood concentration of lipoprotein(a) (Lp(a)) and triglycerides (TG) has been demonstrated. The larger the VLDL particle size, the greater the presence of VLDL rich in apoliprotein E and in subjects with the apoE2/E2 genotype, the lower Lp(a) concentration. The mechanism of this inverse association is unknown. The objective of this analysis was to evaluate the Lp(a)-TG association in patients treated at the lipid units included in the registry of the Spanish Society of Atherosclerosis (SEA) by comparing the different dyslipidemias. PATIENTS AND METHODS: Five thousand two hundred and seventy-five subjects ≥18 years of age registered in the registry before March 31, 2023, with Lp(a) concentration data and complete lipid profile information without treatment were included. RESULTS: The mean age was 53.0 ± 14.0 years, with 48% women. The 9.5% of subjects (n = 502) had diabetes and the 22.4% (n = 1184) were obese. The median TG level was 130 mg/dL (IQR 88.0-210) and Lp(a) 55.0 nmol/L (IQR 17.9-156). Lp(a) concentration showed a negative association with TG concentration when TG values exceeded 300 mg/dL. Subjects with TG > 1000 mg/dL showed the lowest level of Lp(a), 17.9 nmol/L, and subjects with TG < 300 mg/dL had a mean Lp(a) concentration of 60.1 nmol/L. In subjects without diabetes or obesity, the inverse association of Lp(a)-TG was especially important (p < 0.001). The median Lp(a) was 58.3 nmol/L in those with TG < 300 mg/dL and 22.0 nmol/L if TG > 1000 mg/dL. No association was found between TG and Lp(a) in subjects with diabetes and obesity, nor in subjects with familial hypercholesterolemia. In subjects with multifactorial combined hyperlipemia with TG < 300 mg/dL, Lp(a) was 64.6 nmol/L; in the range of 300-399 mg/dL of TG, Lp(a) decreased to 38. 8 nmol/L, and up to 22.3 nmol/L when TG > 1000 mg/dL. CONCLUSIONS: Our results show an inverse Lp(a)-TG relationship in TG concentrations > 300 mg/dL in subjects without diabetes, obesity and without familial hypercholesterolemia. Our results suggest that, in those hypertriglyceridemias due to hepatic overproduction of VLDL, the formation of Lp(a) is reduced, unlike those in which the peripheral catabolism of TG-rich lipoproteins is reduced.

Impact of conducting a genetic study on the management of familial hypercholesterolemia.

BACKGROUND: Clinically diagnosed familial hypercholesterolemia (FH) may require a genetic test (GT) to confirm diagnosis. GT availability/accessibility is resource-dependent and usually restricted to specialized clinics. While GT has a diagnostic value, it has not yet defined its impact on long-term management and prognosis of FH. OBJECTIVE: The aim was to identify the clinical characteristics associated with the request for a GT in suspected heterozygous FH. METHODS: Retrospective study including adult patients with clinically suspected to be FH. Positive GT (GT+) was defined as having a pathogenic/likely pathogenic variant. Patients were stratified based on whether they had a genetic study conducted, and among those with a genetic study, according to those who did or did not have a GT+. RESULTS: From 4854 patients included, 3090 were performed a GT (GT+: 2113). Median follow-up: 6.2 years. A younger age, FH-related physical signs, premature coronary disease, higher low-density lipoprotein cholesterol (LDLc) and lower body mass index and triglycerides, associated higher odds of being conducted a genetic study. These patients had higher baseline LDLc (252 mg/dL vs. 211 mg/dL among clinically diagnosed patients) and experienced larger reductions over the follow-up (157.7 mg/dL vs. 113.5 mg/dL, respectively). A similar pattern was observed among patients with GT+ (vs. negative GT). LDLc target attainment was low but increased to 66-95% when a triple combination with statin/ezetimibe/proprotein convertase subtilisin kexin type 9-inhibitor was used. Cardiovascular events occurred in 3.2% and 3.1% of patients who conducted/not conducted a genetic study. Patients conducted a genetic analysis and those with GT+ tended to present the events earlier. CONCLUSIONS: Genetic study, vs. having a clinical-only diagnosis, impacts the management of FH. Cardiovascular prognosis was similar in both groups, perhaps as a result of the more intensive management of patients with a genetic study.

Contribution of APOE Genetic Variants to Dyslipidemia.

BACKGROUND: apo (apolipoprotein) E has crucial role in lipid metabolism. The genetic variation in APOE gene is associated with monogenic disorders and contributes to polygenic hypercholesterolemia and to interindividual variability in cholesterol. APOE rare variants may be involved in the phenotype of genetic hyperlipidemias. METHODS: Exon 4 of APOE were sequenced in all consecutive unrelated subjects with primary hyperlipidemia from a Lipid Unit (n=3667) and 822 random subjects from the Aragon Workers Health Study. Binding affinity of VLDL (very low-density lipoprotein) to LDL receptor of pathogenic predicted apoE variants was analyzed in vitro. Lipoprotein particle number, size, and composition were studied by nuclear magnetic resonance. RESULTS: In addition to common polymorphisms giving rise to APOE2 and APOE4, 14 gene variants were found in exon 4 of APOE in 65 subjects. p.(Leu167del) in 8 patients with isolated hypercholesterolemia and in 8 patients with combined hyperlipidemia. Subjects with p.(Arg121Trp), p.(Gly145Asp), p.(Arg154Ser), p.(Arg163Cys), p.(Arg165Trp), and p.(Arg168His) variants met dysbetalipoproteinemia lipid criteria and were confirmed by nuclear magnetic resonance. VLDL affinity for the LDL receptor of p.(Arg163Cys) and p.(Arg165Trp) heterozygous carriers had intermedium affinity between APOE2/2 and APOE3/3. p.(Gly145Asp) and p.(Pro220Leu) variants had higher affinity than APOE3/3. CONCLUSIONS: APOE genetic variation contributes to the development of combined hyperlipidemia, usually dysbetalipoproteinemia, and familial hypercholesterolemia. The lipid phenotype in heterozygous for dysbetalipoproteinemia-associated mutations is milder than the homozygous APOE2/2-associated phenotype. Subjects with dysbetalipoproteinemia and absence of APOE2/2 are good candidates for the study of pathogenic variants in APOE. However, more investigation is required to elucidate the significance of rarer variants of apoE.

Diagnosis of Familial Dysbetalipoproteinemia Based on the Lipid Abnormalities Driven by APOE2/E2 Genotype.

BACKGROUND: Familial dysbetalipoproteinemia (FDBL) is a monogenic disease due to variants in APOE with a highly variable phenotype. Current diagnostic lipid-based methods have important limitations. The objective is twofold: to define characteristics of dysbetalipoproteinemia (DBL) based on the analysis of APOE in patients from a lipid unit and in a sample from the general population, and to propose a screening algorithm for FDBL. METHODS: Lipids and APOE genotype from consecutive unrelated subjects from Miguel Servet University Hospital (MSUH) (n 3603), subjects from the general population participants of the Aragon Workers Health Study (AWHS) (n 4981), and selected subjects from external lipid units (Ext) (n 390) were used to define DBL criteria and to train and validate a screening tool. RESULTS: Thirty-five subjects from MSUH, 21 subjects from AWHS, and 31 subjects from Ext were APOE2/2 homozygous. The combination of non high-density lipoprotein cholesterol (non-HDLc)/apoB 1.7 plus triglycerides/apoB 1.35, in mg/dL (non-HDLc [mmol/L]/apolipoprotein B (apoB) [g/L] 4.4 and triglycerides [mmol/L]/apoB [g/L] 3.5), provided the best diagnostic performance for the identification of subjects with hyperlipidemia and APOE2/2 genotype (sensitivity 100 in the 3 cohorts, and specificity 92.8 [MSUH], 80.9 [AWHS], and 77.6 [Ext]). This improves the performance of previous algorithms. Similar sensitivity and specificity were observed in APOE2/2 subjects receiving lipid-lowering drugs. CONCLUSIONS: The combination of non-HDLc/apoB and triglycerides/apoB ratios is a valuable tool to diagnose DBL in patients with hyperlipidemia with or without lipid-lowering drugs. FDBL diagnosis requires DBL and the presence of a compatible APOE genotype. Most adult APOE2/2 subjects express DBL, making FDBL as common as familial hypercholesterolemia in the population.

APOE Genotypes Modulate Inflammation Independently of Their Effect on Lipid Metabolism.

The association between APOE genotypes and cardiovascular disease (CVD) is partially mediated by LDL-cholesterol concentration but persists after adjusting for lipid levels and other cardiovascular risk factors. Data from the Aragon Workers Health Study (AWHS) (n = 4159) and the Lipid Unit at the Hospital Universitario Miguel Servet (HUMS) (n = 3705) were used to investigate the relationship between C-reactive protein (CRP) levels and APOE genotype. Lipoprotein particle and GlycA concentrations were analyzed in a subsample from AWHS. APOE genotyping was carried out by the Sanger method in both cohorts. APOE4 carriers had significantly lower levels of CRP than APOE3 carriers. Furthermore, APOE4 carriers had cholesterol-enriched LDL particles compared to APOE2 carriers. APOE4 carriers also had higher concentrations of small, medium, and large LDL particles. CRP levels were not associated with lipoprotein particle number, size, or composition. GlycA levels were not associated with APOE genotypes. However, GlycA levels were significantly associated with the size and the amount of cholesterol contained in HDL, VLDL, and LDL particles. APOE genotype influences CRP concentration regardless of lipid profile. APOE2 carriers showed the highest CRP levels, followed by APOE3 and APOE4. A more atherogenic lipid profile, but not inflammatory markers could partly explain the higher CVD risk observed in APOE4 carriers.

A mechanism-based operational definition and classification of hypercholesterolemia.

In contrast to strong evidence-based clinical recommendations for lipid-lowering treatment, there is no analogous definitive diagnostic definition of hypercholesterolemia and its various subtypes. For many clinicians, guideline indications for hypolipidemic treatment can become broadly conflated with hypercholesterolemia in a non-specific sense. In this statement, we propose a unified definition and mechanism-based classification of hypercholesterolemia, which in turn should help to stratify patients and guide efficient diagnosis without interfering with the current strategies of ASCVD risk reduction.

Current causes of death in familial hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH) is a codominant autosomal disease characterized by high low-density lipoprotein cholesterol (LDLc) and a high risk of premature cardiovascular disease (CVD). The molecular bases have been well defined, and effective lipid lowering is possible. This analysis aimed to study the current major causes of death of genetically defined heterozygous familial hypercholesterolemia (heFH). METHODS: A case‒control study was designed to analyse life-long mortality in a group of heFH and control families. Data from first-degree family members of cases and controls (nonconsanguineous cohabitants), including deceased relatives, were collected from a questionnaire and review of medical records. Mortality was compared among heFH patients, nonheFH patients, and nonconsanguineous family members. RESULTS: A total of 813 family members were analysed, 26.4% of whom were deceased. Among the deceased, the mean age of death was 69.3 years in heFH individuals, 73.5 years in nonheFH individuals, and 73.2 years in nonconsanguineous individuals, without significant differences. CVD was the cause of death in 59.7% of heFH individuals, 37.7% of nonheFH individuals, and 37.4% of nonconsanguineous individuals (P = 0.012). These differences were greater after restricting the analyses to parents. The hazard ratio of dying from CVD was 2.85 times higher (95% CI, (1.73-4.69) in heFH individuals than in individuals in the other two groups (non-FH and nonconsanguineous), who did not differ in their risk. CONCLUSIONS: CVD mortality in heFH individuals is lower and occurs later than that described in the last century but is still higher than that in non-FH individuals. This improved prognosis of CVD risk is not associated with changes in non-CVD mortality.

Triglyceride Metabolism Modifies Lipoprotein(a) Plasma Concentration.

BACKGROUND: Lipoprotein(a) (Lp(a)) is a significant cardiovascular risk factor. Knowing the mechanisms that regulate its concentration can facilitate the development of Lp(a)-lowering drugs. This study analyzes the relationship between triglycerides (TGs) and Lp(a) concentrations, cross-sectionally and longitudinally, and the influence of the number and composition of TG-rich lipoproteins, and the APOE genotype. METHODS: Data from Aragon Workers Health Study (AWHS) (n = 5467), National Health and Nutrition Examination Survey III phase 2 (n = 3860), and Hospital Universitario Miguel Servet (HUMS) (n = 2079) were used for cross-sectional TG and Lp(a) relationship. Lp(a) intrasubject variation was studied in AWHS participants and HUMS patients with repeated measurements. TG-rich lipoproteins were quantified by nuclear magnetic resonance in a subsample from AWHS. Apolipoproteins B and E were quantified by Luminex in very low-density lipoprotein (VLDL) isolated by ultracentrifugation, from HUMS samples. APOE genotyping was carried in AWHS and HUMS participants. Regression models adjusted for age and sex were used to study the association. RESULTS: The 3 studies showed an inverse relationship between TG and Lp(a). Increased VLDL number, size, and TG content were associated with significantly lower Lp(a). There was an inverse association between the apoE concentration in VLDL and Lp(a). No significant association was observed for apolipoprotein (apo)B. Subjects carrying the apoE2/E2 genotype had significantly lower levels of Lp(a). CONCLUSION: Our results show an inverse relationship Lp(a)-TG. Subjects with larger VLDL size have lower Lp(a), and lower values of Lp(a) were present in patients with apoE-rich VLDL and apoE2/E2 subjects. Our results suggest that bigger VLDLs and VLDLs enriched in apoE are inversely involved in Lp(a) plasma concentration.

Leu22_Leu23 Duplication at the Signal Peptide of PCSK9 Promotes Intracellular Degradation of LDLr and Autosomal Dominant Hypercholesterolemia.

BACKGROUND: PCSK9 (Proprotein convertase subtilisin/kexin type 9) regulates LDL-C (low-density lipoprotein cholesterol) metabolism by targeting LDLr (LDL receptor) for lysosomal degradation. PCSK9 gain-of-function variants cause autosomal dominant hypercholesterolemia by reducing LDLr levels, the D374Y variant being the most severe, while loss-of-function variants are associated with low LDL-C levels. Gain-of-function and loss-of-function activities have also been attributed to variants occurring in the PCSK9 signal peptide. Among them, L11 is a very rare PCSK9 variant that seems to increase LDL-C values in a moderate way causing mild hypercholesterolemia. METHODS: Using molecular biology and biophysics methodologies, activities of L8 and L11 variants, both located in the leucine repetition stretch of the signal peptide, have been extensively characterized in vitro. RESULTS: L8 variant is not associated with increased LDLr activity, whereas L11 activity is increased by ≈20% compared with wt PCSK9. The results suggest that the L11 variant reduces LDLr levels intracellularly by a process resulting from impaired cleavage of the signal peptide. This would lead to less efficient LDLr transport to the cell membrane and promote LDLr intracellular degradation. CONCLUSIONS: Deletion of a leucine in the signal peptide in L8 variant does not affect PCSK9 activity, whereas the leucine duplication in the L11 variant enhances LDLr intracellular degradation. These findings highlight the importance of deep in vitro characterization of PCSK9 genetic variants to determine pathogenicity and improve clinical diagnosis and therapy of inherited familial hypercholesterolemia disease.

Association of Cholesterol and Oxysterols in Adipose Tissue With Obesity and Metabolic Syndrome Traits.

OBJECTIVE: Adipose tissue stores a substantial amount of body cholesterol in humans. Obesity is associated with decreased concentrations of serum cholesterol. During weight gain, adipose tissue dysfunction might be one of the causes of metabolic syndrome. The aim of this study is to evaluate cholesterol storage and oxidized metabolites in adipose tissue and their relationship with metabolic clinical characteristics. METHODS: Concentrations of cholesterol and oxysterols (27-hydroxycholesterol and 24S-hydroxycholesterol) in subcutaneous and visceral adipose tissue were determined by high-performance liquid chromatography with tandem mass spectrometry in 19 adult women with body mass index between 23 and 40 kg/m2 from the FAT expandability (FATe) study. Tissue concentration values were correlated with biochemical and clinical characteristics using nonparametric statistics. RESULTS: Insulin correlated directly with 24S-hydroxycholesterol in both adipose tissues and with 27-hydroxycholesterol in visceral tissue. Leptin correlated directly with 24S-hydroxycholesterol in subcutaneous adipose tissue. Tissue cholesterol correlated directly with 27-hydroxycholesterol in both adipose tissues and with 24S-hydroxycholesterol in visceral tissue, where cholesterol correlation with 24S-hydroxycholesterol was higher than with 27-hydroxycholesterol. In addition, some tendencies were observed: serum high-density lipoprotein cholesterol tended to be inversely correlated with visceral adipose tissue cholesterol; high-sensitivity C-reactive protein tended to be correlated directly with subcutaneous adipose 24S-hydroxycholesterol and inversely with visceral 27-hydroxycholesterol. CONCLUSIONS: Adipose tissue oxysterols are associated with blood insulin and insulin resistance. Tissue cholesterol correlated more with 27-hydroxycholesterol in subcutaneous adipose tissue and with 24S-hydroxycholesterol in visceral adipose tissue. Levels of adipose 24S-hydroxycholesterol seem to be correlated with some metabolic syndrome symptoms and inflammation while adipose 27-hydroxycholesterol could represent some protection against them.

Effect of the Consumption of Alcohol-Free Beers with Different Carbohydrate Composition on Postprandial Metabolic Response.

BACKGROUND: We investigated the postprandial effects of an alcohol-free beer with modified carbohydrate (CH) composition compared to regular alcohol-free beer. METHODS: Two randomized crossover studies were conducted. In the first study, 10 healthy volunteers received 25 g of CH in four different periods, coming from regular alcohol-free beer (RB), alcohol-free beer enriched with isomaltulose and a resistant maltodextrin (IMB), alcohol-free beer enriched with resistant maltodextrin (MB), and a glucose-based beverage. In the second study, 20 healthy volunteers were provided with 50 g of CH from white bread (WB) plus water, or with 14.3 g of CH coming from RB, IMB, MB, and extra WB. Blood was sampled after ingestion every 15 min for 2 h. Glucose, insulin, incretin hormones, TG, and NEFAs were determined in all samples. RESULTS: The increase in glucose, insulin, and incretin hormones after the consumption of IMB and MB was significantly lower than after RB. The consumption of WB with IMB and MB showed significantly less increase in glucose levels than WB with water or WB with RB. CONCLUSIONS: The consumption of an alcohol-free beer with modified CH composition led to a better postprandial response compared to a conventional alcohol-free beer.

Toxic Metals and Subclinical Atherosclerosis in Carotid, Femoral, and Coronary Vascular Territories: The Aragon Workers Health Study.

OBJECTIVE: Studies evaluating the association of metals with subclinical atherosclerosis are mostly limited to carotid arteries. We assessed individual and joint associations of nonessential metals exposure with subclinical atherosclerosis in 3 vascular territories. Approach and Results: One thousand eight hundred seventy-three Aragon Workers Health Study participants had urinary determinations of inorganic arsenic species, barium, cadmium, chromium, antimony, titanium, uranium, vanadium, and tungsten. Plaque presence in carotid and femoral arteries was determined by ultrasound. Coronary Agatston calcium score ≥1 was determined by computed tomography scan. Median arsenic, barium, cadmium, chromium, antimony, titanium, uranium, vanadium, and tungsten levels were 1.83, 1.98, 0.27, 1.18, 0.05, 9.8, 0.03, 0.66, and 0.23 µg/g creatinine, respectively. The adjusted odds ratio (95% CI) for subclinical atherosclerosis presence in at least one territory was 1.25 (1.03-1.51) for arsenic, 1.67 (1.22-2.29) for cadmium, and 1.26 (1.04-1.52) for titanium. These associations were driven by arsenic and cadmium in carotid, cadmium and titanium in femoral, and titanium in coronary territories and mostly remained after additional adjustment for the other relevant metals. Titanium, cadmium, and antimony also showed positive associations with alternative definitions of increased coronary calcium. Bayesian Kernel Machine Regression analysis simultaneously evaluating metal associations suggested an interaction between arsenic and the joint cadmium-titanium exposure. CONCLUSIONS: Our results support arsenic and cadmium and identify titanium and potentially antimony as atherosclerosis risk factors. Exposure reduction and mitigation interventions of these metals may decrease cardiovascular risk in individuals without clinical disease.

Arsenic exposure and human blood DNA methylation and hydroxymethylation profiles in two diverse populations from Bangladesh and Spain.

BACKGROUND: Associations of arsenic (As) with the sum of 5-mC and 5-hmC levels have been reported; however, As exposure-related differences of the separated 5-mC and 5-hmC markers have rarely been studied. METHODS: In this study, we evaluated the association of arsenic exposure biomarkers and 5-mC and 5-hmC in 30 healthy men (43-55 years) from the Aragon Workers Health Study (AWHS) (Spain) and 31 healthy men (31-50 years) from the Folic Acid and Creatinine Trial (FACT) (Bangladesh). We conducted 5-mC and 5-hmC profiling using Infinium MethylationEPIC arrays, on paired standard and modified (ox-BS in AWHS and TAB in FACT) bisulfite converted blood DNA samples. RESULTS: The median for the sum of urine inorganic and methylated As species (ΣAs) (µg/L) was 12.5 for AWHS and 89.6 for FACT. The median of blood As (µg/L) was 8.8 for AWHS and 10.2 for FACT. At a statistical significance p-value cut-off of 0.01, the differentially methylated (DMP) and hydroxymethylated (DHP) positions were mostly located in different genomic sites. Several DMPs and DHPs were consistently found in AWHS and FACT both for urine ΣAs and blood models, being of special interest those attributed to the DIP2C gene. Three DMPs (annotated to CLEC12A) for AWHS and one DHP (annotated to NPLOC4) for FACT remained statistically significant after false discovery rate (FDR) correction. Pathways related to chronic diseases including cardiovascular, cancer and neurological were enriched. CONCLUSIONS: While we identified common 5-hmC and 5-mC signatures in two populations exposed to varying levels of inorganic As, differences in As-related epigenetic sites across the study populations may additionally reflect low and high As-specific associations. This work contributes a deeper understanding of potential epigenetic dysregulations of As. However, further research is needed to confirm biological consequences associated with DIP2C epigenetic regulation and to investigate the role of 5-hmC and 5-mC separately in As-induced health disorders at different exposure levels.

Lipoprotein(a) in hereditary hypercholesterolemia: Influence of the genetic cause, defective gene and type of mutation.

BACKGROUND AND AIMS: Lipoprotein(a) [Lp(a)] concentration in heterozygous familial hypercholesterolemia (heFH) is not well established. Whether the genetic defect responsible for heFH plays a role in Lp(a) concentration is unknown. We aimed to compare Lp(a) in controls from a healthy population, in genetically diagnosed heFH and mutation-negative hypercholesterolemia subjects, and to assess the influence on Lp(a) of the genetic defect responsible for heFH. METHODS: We conducted a cross-sectional study, performed in a lipid clinic in Spain. We studied adults with suspected heFH and a genetic study of FH genes (LDLR, APOB, APOE and PCSK9) and controls from de Aragon Workers' Health Study. HeFH patients from the Dyslipidemia Registry of the Spanish Atherosclerosis Society (SEA) were used as validation cohort. RESULTS: Adjusted geometric means (95% confidence interval) of Lp(a) in controls (n = 1059), heFH (n = 500), and mutation-negative subjects (n = 860) were 14.9 mg/dL (13.6, 16.4), 21.9 mg/dL (18.1, 25.6) and 37.4 mg/dL (33.3, 42.1), p < 0.001 in all comparisons. Among heFH subjects, APOB-dependent FH showed the highest Lp(a), 36.5 mg/dL (22.0, 60.8), followed by LDLR-dependent FH, 21.7 mg/dL (17.9, 26.4). These differences were also observed in heFH from the SEA cohort. The number of plasminogen-like kringle IV type-2 repeats of LPA, the hypercholesterolemia polygenic score or LDLc concentration did not explain these differences. In LDLR-dependent FH, Lp(a) levels were not different depending on the affected protein domain. CONCLUSIONS: Lp(a) is elevated in mutation-negative subjects and in heFH. The concentration of Lp(a) in heFH varies in relation to the responsible gene. Higher Lp(a) in heFH is not explained by their higher LDLc.

MLb-LDLr: A Machine Learning Model for Predicting the Pathogenicity of LDLr Missense Variants.

Untreated familial hypercholesterolemia (FH) leads to atherosclerosis and early cardiovascular disease. Mutations in the low-density lipoprotein receptor (LDLr) gene constitute the major cause of FH, and the high number of mutations already described in the LDLr makes necessary cascade screening or in vitro functional characterization to provide a definitive diagnosis. Implementation of high-predicting capacity software constitutes a valuable approach for assessing pathogenicity of LDLr variants to help in the early diagnosis and management of FH disease. This work provides a reliable machine learning model to accurately predict the pathogenicity of LDLr missense variants with specificity of 92.5% and sensitivity of 91.6%.

Gene supplementation of CYP27A1 in the liver restores bile acid metabolism in a mouse model of cerebrotendinous xanthomatosis.

Cerebrotendinous xanthomatosis (CTX) is an autosomal recessive disease caused by mutations in the CYP27A1 gene, encoding the sterol 27-hydroxylase. Disruption of the bile acid biosynthesis pathway and accumulation of toxic precursors such as cholestanol cause chronic diarrhea, bilateral juvenile cataracts, tissue deposition of cholestanol and cholesterol (xanthomas), and progressive motor/neuropsychiatric alterations. We have evaluated the therapeutic potential of adeno-associated virus (AAV) vectors expressing CYP27A1 in a CTX mouse model. We found that a vector equipped with a strong liver-specific promoter (albumin enhancer fused with the α1 anti-trypsin promoter) is well tolerated and shows therapeutic effect at relatively low doses (1.5 × 1012 viral genomes [vg]/kg), when less than 20% of hepatocytes overexpress the transgene. This vector restored bile acid metabolism and normalized the concentration of most bile acids in plasma. By contrast, standard treatment (oral chenodeoxycholic acid [CDCA]), while reducing cholestanol, did not normalize bile acid composition in plasma and resulted in supra-physiological levels of CDCA and its derivatives. At the transcriptional level, only the vector was able to avoid the induction of xenobiotic-induced pathways in mouse liver. In conclusion, the overexpression of CYP27A1 in a fraction of hepatocytes using AAV vectors is well tolerated and provides full metabolic restoration in Cyp27a1 -/- mice. These features make gene therapy a feasible option for the etiological treatment of CTX patients.