Metabolomic analysis of plasma from normal-weight adults with hypo-HDL cholesterolemia by UPLC-QTOF MS.

High-density lipoprotein cholesterol (HDL-C) is negatively correlated with atherosclerotic cardiovascular disease. The prevalence of hypo-HDL cholesterolemia is as high as 33.9%. The plasma metabolomic differences between hypo-HDL cholesterolemia populations and normal controls were investigated using ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Participants with hypo-HDL cholesterolemia and normal controls were clearly discriminated from each other on the orthogonal partial least squares-discriminant analysis score plot and a total of 90 differential metabolites were identified, including down-regulated phosphatidylserine [18:0/20:3(8Z,11Z,14Z)], phosphatidylcholine [19:0/18:3(6Z,9Z,12Z)], phosphatidylserine, phosphatidylethanolamine [18:0/20:4(5Z,8Z,11Z,13E) (15Ke)], etc., and up-regulated triglyceride [15:0/18:1(9Z)/18:3(9Z,12Z,15Z)][iso6], 13-methyl-1-tritriacontene, tridodecylamine, etc. Most of the changed metabolites were lipids, notably, a significant part of which were odd chain fatty acid incorporated lipids. Carnitine shuttle was the most significant metabolic pathway, except for the disturbed glycerophospholipid metabolism, glycosphingolipid metabolism and sphingolipid metabolism in participants with hypo-HDL cholesterolemia. We identified the key metabolites and metabolic pathways that may be changed in hypo-HDL cholesterolemia participants, providing useful clues for studying the metabolic mechanisms and for early prevention of hypo-HDL cholesterolemia and dyslipidemia.

Naturally Occurring Variants in LRP1 (Low-Density Lipoprotein Receptor-Related Protein 1) Affect HDL (High-Density Lipoprotein) Metabolism Through ABCA1 (ATP-Binding Cassette A1) and SR-B1 (Scavenger Receptor Class B Type 1) in Humans.

OBJECTIVE: Studies into the role of LRP1 (low-density lipoprotein receptor-related protein 1) in human lipid metabolism are scarce. Although it is known that a common variant in LRP1 (rs116133520) is significantly associated with HDL-C (high-density lipoprotein cholesterol), the mechanism underlying this observation is unclear. In this study, we set out to study the functional effects of 2 rare LRP1 variants identified in subjects with extremely low HDL-C levels. APPROACH AND RESULTS: In 2 subjects with HDL-C below the first percentile for age and sex and moderately elevated triglycerides, we identified 2 rare variants in LRP1: p.Val3244Ile and p.Glu3983Asp. Both variants decrease LRP1 expression and stability. We show in a series of translational experiments that these variants culminate in reduced trafficking of ABCA1 (ATP-binding cassette A1) to the cell membrane. This is accompanied by an increase in cell surface expression of SR-B1 (scavenger receptor class B type 1). Combined these effects may contribute to low HDL-C levels in our study subjects. Supporting these findings, we provide epidemiological evidence that rs116133520 is associated with apo (apolipoprotein) A1 but not with apoB levels. CONCLUSIONS: This study provides the first evidence that rare variants in LRP1 are associated with changes in human lipid metabolism. Specifically, this study shows that LRP1 may affect HDL metabolism by virtue of its effect on both ABCA1 and SR-B1.

Hypoalphalipoproteinemia and BRAFV600E Mutation Are Major Predictors of Aortic Infiltration in the Erdheim-Chester Disease.

Objective- Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis characterized by the infiltration of multiple tissues with lipid-laden histiocytes. Cardiovascular involvement is frequent in ECD and leads to a severe prognosis. The objective of this study was to determine whether an alteration of lipid metabolism participates in the lipid accumulation in histiocytes and the cardiovascular involvement in ECD. Approach and Results- An analysis of plasma lipid levels indicated that male ECD patients carrying the BRAFV600E (B-Raf proto-oncogene, serine/threonine kinase) mutation exhibited hypoalphalipoproteinemia, as demonstrated by low plasma HDL-C (high-density lipoprotein cholesterol) levels. Capacity of sera from male BRAFV600E ECD patients to mediate free cholesterol efflux from human macrophages was reduced compared with control individuals. Cardiovascular involvement was detected in 84% of the ECD patients, and we reported that the presence of the BRAFV600E mutation and hypoalphalipoproteinemia is an independent determinant of aortic infiltration in ECD. Phenotyping of blood CD14+ cells, the precursors of histiocytes, enabled the identification of a specific inflammatory signature associated with aortic infiltration which was partially affected by the HDL phenotype. Finally, the treatment with vemurafenib, an inhibitor of the BRAFV600E mutation, restored the defective sera cholesterol efflux capacity and reduced the aortic infiltration. Conclusions- Our findings indicate that hypoalphalipoproteinemia in male ECD patients carrying the BRAFV600E mutation favors the formation of lipid-laden histiocytes. In addition, we identified the BRAF status and the HDL phenotype as independent determinants of the aortic involvement in ECD with a potential role of HDL in modulating the infiltration of blood CD14+ cells into the aorta.

Identification and functional analysis of missense mutations in the lecithin cholesterol acyltransferase gene in a Chilean patient with hypoalphalipoproteinemia.

BACKGROUND: Lecithin-cholesterol acyltransferase (LCAT) is a plasma enzyme that esterifies cholesterol in high- and low-density lipoproteins (HDL and LDL). Mutations in LCAT gene causes familial LCAT deficiency, which is characterized by very low plasma HDL-cholesterol levels (Hypoalphalipoproteinemia), corneal opacity and anemia, among other lipid-related traits. Our aim is to evaluate clinical/biochemical features of a Chilean family with a proband showing clinical signs of familial LCAT deficiency, as well as to identify and assess the functional effects of LCAT mutations. METHODS: An adult female proband with hypoalphalipoproteinemia, corneal opacity and mild anemia, as well as her first-degree relatives, were recruited for clinical, biochemical, genetic, in-silico and in-vitro LCAT analysis. Sequencing of exons and intron-exon boundaries was performed to identify mutations. Site-directed mutagenesis was carried out to generate plasmids containing cDNA with wild type or mutant sequences. Such expression vectors were transfected to HEK-239 T cells to asses the effect of LCAT variants in expression, synthesis, secretion and enzyme activity. In-silico prediction analysis and molecular modeling was also used to evaluate the effect of LCAT variants. RESULTS: LCAT sequencing identified rare p.V333 M and p.M404 V missense mutations in compound heterozygous state in the proband, as well the common synonymous p.L363 L variant. LCAT protein was detected in proband's plasma, but with undetectable enzyme activity compared to control relatives. HEK-293 T transfected cells with vector expression plasmids containing either p.M404 V or p.V333 M cDNA showed detectable LCAT protein expression both in supernatants and lysates from cultured cells, but with much lower enzyme activity compared to cells transfected with the wild-type sequence. Bioinformatic analyses also supported a causal role of such rare variations in LCAT lack of function. Additionally, the proband carried the minor allele of the synonymous p.L363 L variant. However, this variant is unlikely to affect the clinical phenotype of the proband given its relatively high frequency in the Chilean population (4%) and its small putative effect on plasma HDL-cholesterol levels. CONCLUSION: Genetic, biochemical, in vitro and in silico analyses indicate that the rare mutations p.M404 V and p.V333 M in LCAT gene lead to suppression of LCAT enzyme activity and cause clinical features of familial LCAT deficiency.

Poor glycemic control in type 2 diabetes enhances functional and compositional alterations of small, dense HDL3c.

High-density lipoprotein (HDL) possesses multiple biological activities; small, dense HDL3c particles displaying distinct lipidomic composition exert potent antiatherogenic activities which can be compromised in dyslipidemic, hyperglycemic insulin-resistant states. However, it remains indeterminate (i) whether such functional HDL deficiency is related to altered HDL composition, and (ii) whether it originates from atherogenic dyslipidemia, dysglycemia, or both. In the present work we analyzed compositional characteristics of HDL subpopulations and functional activity of small, dense HDL3c particles in treatment-naïve patients with well-controlled (n=10) and poorly-controlled (n=8) type 2 diabetes (T2D) and in normolipidemic age- and sex-matched controls (n=11). Our data reveal that patients with both well- and poorly-controlled T2D displayed dyslipidemia and low-grade inflammation associated with altered HDL composition. Such compositional alterations in small, dense HDL subfractions were specifically correlated with plasma HbA1c levels. Further analysis using a lipidomic approach revealed that small, dense HDL3c particles from T2D patients with poor glycemic control displayed additional modifications of their chemical composition. In parallel, antioxidative activity of HDL3c towards oxidation of low-density lipoprotein was diminished. These findings indicate that defective functionality of small, dense HDL particles in patients with T2D is not only affected by the presence of atherogenic dyslipidemia, but also by the level of glycemic control, reflecting compositional alterations of HDL.

Reduced platelet count, but no major platelet function abnormalities, are associated with loss-of-function ATP-binding cassette-1 gene mutations.

Loss-of-function mutations of the the ATP-binding cassette-1 (ABCA1) gene are the cause of Tangier disease (TD) in homozygous subjects and familial HDL deficiency (FHD) in heterozygous subjects. These disorders are characterized by reduced plasma HDL-cholesterol (HDL-C) and altered efflux of cholesterol from cells. Previous studies in TD patients and ABCA1-/- murine models reported defects in platelet count, morphology, and function, but the issue is still controversial. We analyzed three subjects with low to very low HDL-C levels due to the loss-of-function mutations of the ABCA1 gene. Two related patients with FHD were heterozygous carriers of two mutations on the same ABCA1 allele; one, with TD, was homozygous for a different mutation. Mild to moderate thrombocytopenia was observed in all the patients. No morphological platelet abnormalities were detected under optical or EM. History of moderate bleeding tendency was recorded only in one of the FHD patients. Only limited alterations in platelet aggregation and activation of the integrin αIIbß3 were observed in one FHD patient. While α-granule secretion (P-selectin), content, and secretion of platelet δ-granules (serotonin, ATP, and ADP) and thromboxane (TX) A2 synthesis were normal in all the patients, the expression of lysosomal CD63, in response to some agonists, was reduced in TD patients. In conclusion, three patients carrying ABCA1 genetic variants had low platelet count, with the lowest values observed in TD, not associated with major alterations in platelet morphology and response to agonists or bleeding.

Effect of open-label infusion of an apoA-I-containing particle (CER-001) on RCT and artery wall thickness in patients with FHA.

Reverse cholesterol transport (RCT) contributes to the anti-atherogenic effects of HDL. Patients with the orphan disease, familial hypoalphalipoproteinemia (FHA), are characterized by decreased tissue cholesterol removal and an increased atherogenic burden. We performed an open-label uncontrolled proof-of-concept study to evaluate the effect of infusions with a human apoA-I-containing HDL-mimetic particle (CER-001) on RCT and the arterial vessel wall in FHA. Subjects received 20 infusions of CER-001 (8 mg/kg) during 6 months. Efficacy was assessed by measuring (apo)lipoproteins, plasma-mediated cellular cholesterol efflux, fecal sterol excretion (FSE), and carotid artery wall dimension by MRI and artery wall inflammation by (18)F-fluorodeoxyglucose-positron emission tomography/computed tomography scans. We included seven FHA patients: HDL-cholesterol (HDL-c), 13.8 [1.8-29.1] mg/dl; apoA-I, 28.7 [7.9-59.1] mg/dl. Following nine infusions in 1 month, apoA-I and HDL-c increased directly after infusion by 27.0 and 16.1 mg/dl (P = 0.018). CER-001 induced a 44% relative increase (P = 0.018) in in vitro cellular cholesterol efflux with a trend toward increased FSE (P = 0.068). After nine infusions of CER-001, carotid mean vessel wall area decreased compared with baseline from 25.0 to 22.8 mm(2) (P = 0.043) and target-to-background ratio from 2.04 to 1.81 (P = 0.046). In FHA-subjects, CER-001 stimulates cholesterol mobilization and reduces artery wall dimension and inflammation, supporting further evaluation of CER-001 in FHA patients.

Defective functionality of HDL particles in familial apoA-I deficiency: relevance of alterations in HDL lipidome and proteome.

To evaluate functional and compositional properties of HDL in subjects from a kindred of genetic apoA-I deficiency, two homozygotes and six heterozygotes, with a nonsense mutation at APOA1 codon -2, Q[-2]X, were recruited together with age- and sex-matched healthy controls (n = 11). Homozygotes displayed undetectable plasma levels of apoA-I and reduced levels of HDL-cholesterol (HDL-C) and apoC-III (5.4% and 42.6% of controls, respectively). Heterozygotes displayed low HDL-C (21 ± 9 mg/dl), low apoA-I (79 ± 24 mg/dl), normal LDL-cholesterol (132 ± 25 mg/dl), and elevated TG (130 ± 45 mg/dl) levels. Cholesterol efflux capacity of ultracentrifugally isolated HDL subpopulations was reduced (up to -25%, P < 0.01, on a glycerophospholipid [GP] basis) in heterozygotes versus controls. Small, dense HDL3 and total HDL from heterozygotes exhibited diminished antioxidative activity (up to -48%, P < 0.001 on a total mass basis) versus controls. HDL subpopulations from both homozygotes and heterozygotes displayed altered chemical composition, with depletion in apoA-I, GP, and cholesteryl ester; enrichment in apoA-II, free cholesterol, and TG; and altered phosphosphingolipidome. The defective atheroprotective activities of HDL were correlated with altered lipid and apo composition. These data reveal that atheroprotective activities of HDL particles are impaired in homozygous and heterozygous apoA-I deficiency and are intimately related to marked alterations in protein and lipid composition.

Impact of hypoalphalipoproteinemia on quality of life in Taiwanese women with central obesity.

PURPOSE: To investigate the relationship between health-related quality of life (HRQoL) and different cutoff value of low level of high-density lipoprotein cholesterol (HDL-C) in Taiwanese women with different definition of obesity. METHODS: Prospective observational study in women with central obesity was conducted in Taipei City Hospital. A total of 572 women were screened at our clinic, and 227 of them with a body mass index ≧27 kg/m2 defined by the Department of Health in Taiwan and weight circumference ≧80 cm were eligible for the study. We defined two groups as group A-low HDL (HDL-C < 40 mg/dL) and group B-high HDL (HDL-C < 50 mg/dL) according to different definition of hypoalphalipoproteinemia in obese women. RESULTS: Significantly reduced HRQoL score was noted in group A-low HDL compared to group A-high HDL (HDL-C ≧ 40 mg/dL), but not between group B-low HDL and group B-high HDL (HDL-C ≧ 50 mg/dL). Positively correlation was noted between HDL-C level and physical domain of HRQoL score. HDL-C contributes independently to physical domain of HRQoL score after controlling for other factors. Decreased leptin and adiponectin level were noted in hypoalphalipoproteinemia groups. CONCLUSION: Taiwanese obese women with hypoalphalipoproteinemia have adverse impact on HRQoL, especially when the HDL-C level is lower than 40 mg/dL. Both hypoalphalipoproteinemia and hypertension accounted for a great variance to lower scores of physical domain of HRQoL with positively correlation with HDL-C level observed. Decreased leptin and adiponectin were also observed in hypoalphalipoproteinemia group, which implied increased cardiovascular risk. HDL-C level may deem as another indicator for HRQoL in women with central obesity.

Classification of metabolic syndrome according to lipid alterations: analysis from the Mexican National Health and Nutrition Survey 2006.

BACKGROUND: There are 16 possible Metabolic Syndrome (MS) combinations out of 5 conditions (glucose intolerance, low levels of high-density lipoprotein Cholesterol (HDL-C), high triglycerides, high blood pressure and abdominal obesity), when selecting those with at least three. Studies suggest that some combinations have different cardiovascular risk. However evaluation of all 16 combinations is complex and difficult to interpret. The purpose of this study is to describe and explore a classification of MS groups according to their lipid alterations. METHODS: This is a cross-sectional study with data from the Mexican National Health and Nutrition Survey 2006. Subjects (n = 5,306) were evaluated for the presence of MS; four mutually-exclusive MS groups were considered: mixed dyslipidemia (altered triglycerides and HDL-C), hypoalphalipoproteinemia: (normal triglycerides but low HDL-C), hypertriglyceridemia (elevated triglycerides and normal HDL-C) and without dyslipidemia (normal triglycerides and HDL-C). A multinomial logistic regression model was fitted in order to identify characteristics that were associated with the groups. RESULTS: The most frequent MS group was hypoalphalipoproteinemia in females (51.3%) and mixed dyslipidemia in males (43.5%). The most prevalent combination of MS for both genders was low HDL-C + hypertension + abdominal obesity (20.4% females, 19.4% males). The hypoalphalipoproteinemia group was characteristic of women and less developed areas of the country. The group without dyslipidemia was more frequent in the highest socioeconomic level and less prevalent in the south of the country. The mixed dyslipidemia group was characteristic of men, and the Mexico City region. CONCLUSIONS: A simple system to classify MS based on lipid alterations was useful to evaluate prevalences by diverse biologic and sociodemographic characteristics. This system may allow prevention and early detection strategies with emphasis on population-specific components and may serve as a guide for future studies on MS and cardiovascular risk.

Why targeting HDL should work as a therapeutic tool, but has not.

Atherosclerosis is one of the most common causes of death and disability in the United States today despite the availability of statins, which reduce hyperlipidemia, a risk factor that predisposes individuals to this disease. Epidemiology of human populations has overwhelmingly demonstrated an inverse correlation between the concentration of plasma high-density lipoprotein (HDL) cholesterol (HDL-C) and the likelihood of developing cardiovascular disease (CVD). Decades of observations and mechanistic studies suggest that one protective function of HDL is its central role in reverse cholesterol transport. In this pathway, the ATP-binding cassette transporter A1 releases intracellular cholesterol, which is packaged with apolipoprotein A-I (apoA-I) into nascent HDL particles and released from the plasma membrane. Further lipidation and maturation of HDL occur in plasma with the eventual uptake by the liver where cholesterol is removed. It is generally accepted that CVD risk can be reduced if plasma HDL-C levels are elevated. Several different pharmacological approaches have been tried; the most popular approach targets the movement of cholesteryl ester from HDL to triglyceride-rich particles by cholesteryl ester transfer protein. Inhibition of cholesteryl ester transfer protein increases plasma HDL-C concentration; however, beneficial effects have yet to be demonstrated, likely the result of off-target effects. These revelations have led to a reevaluation of how elevating HDL concentration could decrease risk. A recent, landmark study showed that the inherent cholesterol efflux capacity of an individual's plasma was a better predictor of CVD status than overall HDL-C concentration. Even more provocative are recent studies showing that apoA-I, the principle protein component of HDL modulates cellular inflammation and oxidation. The following will review all these potential routes explaining how HDL apoA-I can reduce the risk of CVD.

[Hypertriglyceridemia and low HDL cholesterol as high impact factors for metabolic syndrome diagnosis in apparently healthy adults]. / Hipertrigliceridemia e hipoalfalipoproteinemia. Su impacto para diagnosticar síndrome metabólico.

OBJECTIVE: to determine the impact of lipid serum abnormalities and the prevalence of metabolic syndrome (MS) in healthy adults. METHODS: a cross-sectional, prospective and observational study in apparently healthy adults aged 20 to 60 years who had at least three of the following criteria: abdominal obesity (waist circumference > 102 cm in men and > 88 cm in women), triglycerides ≥ 150 mg/dL, HDL cholesterol < 40 mg/dL in men and < 50 mg/dL in women, blood pressure ≥ 130/85 mmHg and fasting glucose ≥ 110 mg/dL). RESULTS: the prevalence of MS was 20 %, being higher in women (67.7 %) than men (32.3 %). However, no dependence was found with gender (χ(2)= 2.059, p = 0.151). The age range with a higher prevalence of was 45-49 years. Low HDL cholesterol [HR = 11,059 (3.559, 34.610) p < 0.01], was present in 67.9 % of women and hypertriglyceridemia [HR = 15.53 (4.975, 48.513) p < 0.01] was present in 60.5 % of men. CONCLUSIONS: the results suggested that hypertriglyceridemia and hypoalphalipoproteinemia are high impact factors for MS in adults.

Total and high molecular weight adiponectin have similar utility for the identification of insulin resistance.

BACKGROUND: Insulin resistance (IR) and related metabolic disturbances are characterized by low levels of adiponectin. High molecular weight adiponectin (HMWA) is considered the active form of adiponectin and a better marker of IR than total adiponectin. The objective of this study is to compare the utility of total adiponectin, HMWA and the HMWA/total adiponectin index (SA index) for the identification of IR and related metabolic conditions. METHODS: A cross-sectional analysis was performed in a group of ambulatory subjects, aged 20 to 70 years, in Mexico City. Areas under the receiver operator characteristic (ROC) curve for total, HMWA and the SA index were plotted for the identification of metabolic disturbances. Sensitivity and specificity, positive and negative predictive values, and accuracy for the identification of IR were calculated. RESULTS: The study included 101 men and 168 women. The areas under the ROC curve for total and HMWA for the identification of IR (0.664 vs. 0.669, P = 0.74), obesity (0.592 vs. 0.610, P = 0.32), hypertriglyceridemia (0.661 vs. 0.671, P = 0.50) and hypoalphalipoproteinemia (0.624 vs. 0.633, P = 0.58) were similar. A total adiponectin level of 8.03 mug/ml was associated with a sensitivity of 57.6%, a specificity of 65.9%, a positive predictive value of 50.0%, a negative predictive value of 72.4%, and an accuracy of 62.7% for the diagnosis of IR. The corresponding figures for a HMWA value of 4.25 mug/dl were 59.6%, 67.1%, 51.8%, 73.7% and 64.2%.The area under the ROC curve of the SA index for the identification of IR was 0.622 [95% CI 0.554-0.691], obesity 0.613 [95% CI 0.536-0.689], hypertriglyceridemia 0.616 [95% CI 0.549-0.683], and hypoalphalipoproteinemia 0.606 [95% CI 0.535-0.677]. CONCLUSIONS: Total adiponectin, HMWA and the SA index had similar utility for the identification of IR and metabolic disturbances.

Prevalence of dyslipidemias in the Mexican National Health and Nutrition Survey 2006.

OBJECTIVE: To describe the prevalence of lipid abnormalities found in the Mexican National Health and Nutrition Survey 2006 (ENSANut 2006). MATERIAL AND METHODS: Information was obtained from 4 040 subjects aged 20 to 69 years, studied after a 9- to 12-hour fast. RESULTS: Median lipid concentrations were: cholesterol 198.5 mg/dl, triglycerides 139.6 mg/dl, HDL-cholesterol 39.0 mg/dl, non-HDL-cholesterol 159.5 mg/dl and LDL-cholesterol 131.5 mg/dl. The most frequent abnormality was HDL-cholesterol below 40 mg/dl with a prevalence of 60.5% (95%CI 58.2-62.8%). Hypercholesterolemia (> 200 mg/dl) had a frequency of abnormality of 43.6% (95%CI 41.4-46.0%). Only 8.6% of the hypercholesterolemic subjects knew their diagnosis. Hypertriglyceridemia (>or= 150 mg/dl) was observed in 31.5% (IC 95% 29.3-33.9%) of the population. CONCLUSIONS: The ENSANUT 2006 data confirm that the prevalence of hypoalphalipoproteinemia and other forms of dyslipidemia in Mexican adults is very high.

Sex-Specific Association between Serum Vitamin D Status and Lipid Profiles: A Cross-Sectional Study of a Middle-Aged and Elderly Chinese Population.

Studies have shown that vitamin D status might be associated with dyslipidaemia, but results are conflicting and there might exist sex differences. The aim of our study was to explore the sex-specific association between vitamin D status and serum lipids and atherogenic index of plasma (AIP, a predictor for atherosclerosis) among Chinese middle-aged and elderly adults. A total of 4,021 middle-aged and elderly participants from a health management centre were included in this cross-sectional study. The individuals were classified into tertiles according to serum 25(OH)D. Linear and logistic regression models were used to estimate the association between vitamin D levels and serum lipids among the tertiles. The mean serum 25(OH)D level was 21.60 (16.60-27.20) ng/mL in all participants. After adjusting for potential confounders, a 10 ng/mL increase in 25(OH)D was associated with decreases of 1.156 mmol/L in triglycerides (TGs) and 0.068 in the AIP and an increase of 0.051 mmol/L in high-density lipoprotein cholesterol (HDL-C) in all subjects. In addition, 25(OH)D deficiency was associated with an increased prevalence of hypertriglyceridaemia (odds ratio (OR), 1.880; 95% confidence interval (CI), 1.351-2.615), hypoalphalipoproteinaemia/HDL (OR, 1.505; 95% CI, 1.146-1.977) and abnormal AIP (OR, 1.933; 95% CI, 1.474-2.534) in males, and 25(OH)D-deficient women had a 2.02-fold higher risk for hypoalphalipoproteinaemia/HDL than women with sufficient 25(OH)D levels (95% CI, 1.044-3.904; all p values <0.05). Vitamin D deficiency was positively associated with the prevalence of dyslipidaemia and abnormal AIP in the middle-aged and elderly Chinese population. And this association was stronger in men than in women.

Multiple splice defects in ABCA1 cause low HDL-C in a family with hypoalphalipoproteinemia and premature coronary disease.

BACKGROUND: Mutations at splice junctions causing exon skipping are uncommon compared to exonic mutations, and two intronic mutations causing an aberrant phenotype have rarely been reported. Despite the high number of functional ABCA1 mutations reported to date, splice variants have been reported infrequently. We screened DNA from a 41 year-old male with low HDL-C (12 mg/dL [0.31 mmol/L]) and a family history of premature coronary heart disease (CHD) using polymerase chain reaction single-strand conformation polymorphism (SSCP) analysis. METHODS: Family members with low levels of HDL-C (n = 6) were screened by SSCP for mutations in ABCA1. Samples with altered SSCP patterns were sequenced directly using either an ABI 3700 or ABI3730Xl DNA Analyzer. To screen for splicing defects, cDNA was isolated from the proband's RNA and was sequenced as above. A series of minigenes were constructed to determine the contribution of normal and defective alleles. RESULTS: Two novel splice variants in ABCA1 were identified. The first mutation was a single base pair change (T->C) in IVS 7, 6 bps downstream from the exon7/intron7 junction. Amplification of cDNA and allelic subcloning identified skipping of Exon 7 that results in the elimination of 59 amino acids from the first extracellular loop of the ABCA1 protein. The second mutation was a single base pair change (G->C) at IVS 31 -1, at the intron/exon junction of exon 32. This mutation causes skipping of exon 32, resulting in 8 novel amino acids followed by a stop codon and a predicted protein size of 1496 AA, compared to normal (2261 AA). Bioinformatic studies predicted an impact on splicing as confirmed by in vitro assays of constitutive splicing. CONCLUSION: In addition to carnitine-acylcarnitine translocase (CACT) deficiency and Hermansky-Pudlak syndrome type 3, this represents only the third reported case in which 2 different splice mutations has resulted in an aberrant clinical phenotype.

HIV disease, metabolic dysfunction and atherosclerosis: A three year prospective study.

HIV infection is known to be associated with cardiometabolic abnormalities; here we investigated the progression and causes of these abnormalities. Three groups of participants were recruited: HIV-negative subjects and two groups of treatment-naïve HIV-positive subjects, one group initiating antiretroviral treatment, the other remaining untreated. Intima-media thickness (cIMT) increased in HIV-positive untreated group compared to HIV-negative group, but treatment mitigated the difference. We found no increase in diabetes-related metabolic markers or in the level of inflammation in any of the groups. Total cholesterol, low density lipoprotein cholesterol and apoB levels were lower in HIV-positive groups, while triglyceride and Lp(a) levels did not differ between the groups. We found a statistically significant negative association between viral load and plasma levels of total cholesterol, LDL cholesterol, HDL cholesterol, apoA-I and apoB. HIV-positive patients had hypoalphalipoproteinemia at baseline, and we found a redistribution of sub-populations of high density lipoprotein (HDL) particles with increased proportion of smaller HDL in HIV-positive untreated patients, which may result from increased levels of plasma cholesteryl ester transfer protein in this group. HDL functionality declined in the HIV-negative and HIV-positive untreated groups, but not in HIV-positive treated group. We also found differences between HIV-positive and negative groups in plasma abundance of several microRNAs involved in lipid metabolism. Our data support a hypothesis that cardiometabolic abnormalities in HIV infection are caused by HIV and that antiretroviral treatment itself does not influence key cardiometabolic parameters, but mitigates those affected by HIV.

[Dyslipidemia prevalence and its relationship with insulin resistance in a population of apparently healthy subjects]. / Prevalencia de dislipidemias en una población de sujetos en apariencia sanos y su relación con la resistencia a la insulina.

OBJECTIVE: Evaluate dyslipidemia prevalence and its association with insulin resistance in a cohort of apparently healthy subjects. MATERIAL AND METHODS: A cross-sectional study was conducted with 1,179 donors ages 35 to 65 years. The sample population was comprised of 71% men, with an average age of 44 +/- 7. Clinical records, anthropometric data, lipid profile, fasting glycaemia, and insulin levels were obtained. RESULTS: Prevalence of hypertriglyceridemia was 57.3%, C-HDL under normal limits was 52.4%, and hypercholesterolemia was 48.7%. In addition, 36.8% of the obese individuals (as measured by waist perimeter) had hypertriglyceridemia/hypoalphalipoproteinemia, 35.2% had mixed dyslipidemia, and 33.4% had hypertriglyceridemia. Patterns of dyslipidemia were higher in subjects diagnosed with insulin resistance. CONCLUSIONS: Insulin resistance associated with hypertriglyceridemia and hypoalphalipoproteinemia was common among our studied population. However, a significant proportion of cases of apparent healthy individuals continue to go undiagnosed.

Associations between hypo-HDL cholesterolemia and cardiometabolic risk factors in middle-aged men and women: Independence of habitual alcohol drinking, smoking and regular exercise.

OBJECTIVE: Hypo-HDL cholesterolemia is a potent cardiovascular risk factor, and HDL cholesterol level is influenced by lifestyles including alcohol drinking, smoking and regular exercise. The aim of this study was to clarify the relationships between hypo-HDL cholesterolemia and cardiovascular risk factors and to determine whether or not these relationships depend on the above-mentioned lifestyles. METHODS: The subjects were 3456 men and 2510 women (35-60 years of age) showing low HDL cholesterol levels (<40mg/dl for men and <50mg/dl for women) and their age-matched control subjects showing normal HDL cholesterol levels. Each cardiometabolic risk factor was compared between the groups with and without hypo-HDL cholesterolemia. Data for hypo-HDL cholesterolemic subjects not having habits of alcohol drinking, smoking and regular exercise (men, n=333; women, n=1410) and their age-matched control subjects were also analysed. RESULTS: Both in men and in women of overall subjects and subjects without histories of alcohol drinking, smoking and regular exercise, odds ratios of subjects with hypo-HDL cholesterolemia vs. subjects with normo-HDL cholesterolemia for high body mass index, high waist-to-height ratio, high triglycerides, high lipid accumulation product and multiple risk factors (three or more out of obesity, hypertension, dyslipidaemia and diabetes) were significantly higher than the reference level of 1.00. These associations in overall subjects were found when the above habits were adjusted. CONCLUSIONS: Hypo-HDL cholesterolemic men and women have adverse cardiovascular profiles, such as obesity, hypertriglyceridemia and multiple risk factors, independently of age, alcohol drinking, smoking and regular exercise.

Low serum HDL-cholesterol concentrations in mid-life predict late-life cognitive impairment in type 2 diabetes: The Fremantle diabetes study.

In a study involving patients with type 2 diabetes assessed annually over 5years, serum HDL-cholesterol was the sole mid-life metabolic predictor of late-life cognitive impairment.