Twenty Apolipoprotein A-I (ApoA-I) variants are responsible for a systemic hereditary amyloidosis in which protein fibrils can accumulate in different organs, leading to their failure. Several ApoA-I amyloidogenic mutations are also associated with hypoalphalipoproteinemia, low ApoA-I and high-density lipoprotein (HDL)-cholesterol plasma levels; however, subjects affected by ApoA-I-related amyloidosis do not show a higher risk of cardiovascular diseases (CVD). The structural features, the lipid binding properties and the functionality of four ApoA-I amyloidogenic variants were therefore inspected in order to clarify the paradox observed in the clinical phenotype of the affected subjects. Read More
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. Read More
Background: The dyslipidemia associated with obesity plays a major role in the development of atherosclerosis and cardiovascular disease. Dyslipidemia in childhood can progress in adult stage. APOE is one of the most important genes that regulate plasma lipid transport and clearance. Read More
Low serum high density lipoprotein cholesterol level (HDL-C) <40 mg/dL in men and <50 mg/dL in women is a significant independent risk factor for cardiovascular disease (CVD), and is often observed in patients with hypertriglyceridemia, obesity, insulin resistance, and diabetes. Patients with marked deficiency of HDL-C (<20 mg/dL) in the absence of secondary causes are much less common (<1% of the population). These patients may have homozygous, compound heterozygous, or heterozygous defects involving the apolipoprotein (APO)AI, ABCA1, or lecithin:cholesterol acyl transferase genes, associated with apo A-I deficiency, apoA-I variants, Tangier disease , familial lecithin:cholesteryl ester acyltransferase deficiency, and fish eye disease. Read More
Recent lifestyle and social environment changes in Japan have been accompanied by increasing incidencerates of metabolic disorders, such as dyslipidemia and diabetes. Therefore, the rates of cardiovascular disease due to the progression of atherosclerosis are also increasing, and cardiovascular disease remains the leading cause of death in Japan. In particular, dyslipidemia, represented by hypercholesterolemia, hypertriglyceridemia, and hypoalphalipoproteinemia, is closely related to the onset and progression of atherosclerosis. Read More
Background: Humans with familial lecithin:cholesterol acyltransferase (LCAT) deficiency (FLD) have extremely low or undetectable high-density lipoprotein cholesterol (HDL-C) levels and by early adulthood develop many manifestations of the disorder, including corneal opacities, anemia, and renal disease.
Objective: To determine if infusions of recombinant human LCAT (rhLCAT) could reverse the anemia, halt progression of renal disease, and normalize HDL in FLD.
Methods: rhLCAT (ACP-501) was infused intravenously over 1 hour on 3 occasions in a dose optimization phase (0. Read More
Human familial lecithin:cholesterol acyltransferase (LCAT) deficiency (FLD) is characterized by low HDL, accumulation of an abnormal cholesterol-rich multilamellar particle called lipoprotein-X (LpX) in plasma, and renal disease. The aim of our study was to determine if LpX is nephrotoxic and to gain insight into the pathogenesis of FLD renal disease. We administered a synthetic LpX, nearly identical to endogenous LpX in its physical, chemical and biologic characteristics, to wild-type and Lcat-/- mice. Read More
Objective: To detect the interactions between six functional polymorphisms in ABCA1 and obesity in Kazakhs with low HDL-C levels.
Methods: A total of 204 patients with low HDL-C and 207 health control subjects, which were randomly selected from among 5692 adult Kazakhs, were matched for age and sex. We genotyped ABCA1 single nucleotide polymorphisms of rs2515602, rs3890182, rs2275542, rs2230806, rs1800976, and rs4149313. Read More
Unlabelled: ESSENTIALS: The role of ATP-binding cassette transporter 1 (ABCA1) in platelet functions is poorly characterized. We studied the impact of ABCA1 deficiency on platelet responses in a mouse model and two Tangier patients. ABCA1-deficient platelets exhibit reduced positive feedback loop mechanisms. Read More
Low levels of high-density lipoprotein cholesterol (HDL-C) and high triglyceride levels contribute to the excess rate of cardiovascular events seen in subjects with type 2 diabetes. Fenofibrate treatment partially reverses dyslipidemia in these subjects. However, a paradoxical marked reduction in HDL-C and HDL's major protein, apolipoprotein A-I, is a complication of fenofibrate in combination with rosiglitazone, an insulin-sensitizing agent. Read More
Tangier disease, characterized by low or absent high-density lipoprotein (HDL), is a rare hereditary lipid storage disorder associated with frequent, but not obligatory, severe premature atherosclerosis due to disturbed reverse cholesterol transport from tissues. The reasons for the heterogeneity in atherogenicity in certain dyslipidemias have not been fully elucidated. Here, using high-performance liquid chromatography with a gel filtration column (HPLC-GFC), we have studied the lipoprotein profile of a 17-year old male patient with Tangier disease who to date has not developed manifest coronary atherosclerosis. Read More
Background: Plasma high density lipoproteins (HDL) are involved in reverse cholesterol transport mediated by the scavenger receptor class B type I (SR-BI). Nicotinic acid increases HDL cholesterol levels, even though its specific impact on SR-BI dependent-cellular cholesterol transport remains unknown.
Aim: To determine the effect of nicotinic acid on HDL particle functionality in cholesterol efflux and uptake mediated by SR-BI in cultured cells in hypoalphalipoproteinemic patients. Read More
Tangier disease (TD) is a rare, autosomal recessive inherited disorder caused by a mutation in the adenosine triphosphate-binding cassette transporter 1 (ABCA1) gene, which results in a decrease in plasma high-density lipoprotein (HDL) levels. Peripheral neuropathy can be seen in approximately 50% of patients with TD, which usually occurs after the age of 15 years, and is characterized by relapsing-remitting mono- or polyneuropathy or syringomyelia-like neuropathy. Herein, we report a 16-year-old female patient who was initially diagnosed with peripheral neuropathy at the age of 13 years. Read More
Cutaneous lipids, endogenously synthetized and transported by lipoproteins, play a pivotal role in maintaining skin barrier. An impairment of extracutaneous lipid trafficking leads to the development of xanthomas, mostly arising in hyperlipidemic patients, but also in subjects with high-density lipoprotein (HDL) deficiency. The aim of this work was to evaluate, in a genetically modified mouse model, lacking two protein components of HDL particles, apolipoprotein(apo)E and apoA-I, the effect of HDL deficiency on skin morphology. Read More
Background/aims: Women after menopause have increased insulin resistance and visceral fat, which may increase the prevalence of nonalcoholic fatty liver disease (NAFLD). However, the pathogenesis of NAFLD in women has not been clearly defined. In this study, we aimed to determine the risk factors for NAFLD in women. Read More
Objective: Molecular diagnosis for subjects with extremely low HDL-C through candidate-gene approaches requires huge effort. Whole exome-sequencing (WES) has already shown approximately ∼30% success in the diagnosis of Mendelian disorders. Moreover, novel in silico prediction software for the pathogenicity of novel missense variants named Combined Annotation Dependent Depletion (CADD) has recently been developed, enabling the objective integration of many diverse annotations into a single measure (C-score) for each variant. Read More
Aim: The prevalence of metabolic syndrome (MetS) increases even in adolescents. The evidence that MetS is associated with the periodontal diseases in adolescents has been understudied. Therefore, our aim was to assess the association between MetS parameters and gingivitis in adolescents. Read More
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. Read More
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. Read More
We investigated the effect of dalcetrapib treatment on phytosterol levels in patients with familial combined hyperlipidemia (FCH) or familial hypoalphalipoproteinemia (FHA) due to mutations in apolipoprotein A1 (ApoA1) or ATP-binding cassette transporter A1 (ABCA1). Patients (n = 40) with FCH or FHA received dalcetrapib 600 mg or placebo in this 4-week, double-blind, crossover study. Lipids, apolipoproteins, cholesteryl ester transfer protein (CETP) activity and mass, and phytosterols were assessed. Read More
Low levels of high-density lipoprotein cholesterol (HDL-C) have been associated with an increased risk of coronary heart disease in prospective population studies and clinical trials of high-risk patients treated with a low to moderate intensity statin. As a result, therapeutic targets were developed to increase concentrations of HDL-C. Subsequently, clinical trials of high-intensity statins have not supported this previously well-established association. Read More
Lecithin cholesterol acyl transferase (LCAT) is a plasma enzyme which esterifies cholesterol, and plays a key role in the metabolism of high-density lipoprotein cholesterol (HDL-C). Genetic disorders of LCAT are associated with lipoprotein abnormalities including low levels of HDL-C and presence of lipoprotein X, and clinical features mainly corneal opacities, changes in erythrocyte morphology and renal failure. Recombinant LCAT is being developed for the treatment of patients with LCAT deficiency. Read More
Objectives: It has been suggested that a low plasma high-density lipoprotein cholesterol (HDL-C) level contributes to the high cardiovascular disease risk of patients with chronic kidney disease (CKD), especially those undergoing haemodialysis (HD). The present study was conducted to gain further understanding of the mechanism(s) responsible for the low HDL-C levels in patients with CKD and to separate the impact of HD from that of the underlying CKD.
Methods: Plasma lipids and lipoproteins, HDL subclasses and various cholesterol esterification parameters were measured in a total of 248 patients with CKD, 198 of whom were undergoing HD treatment and 40 healthy subjects. Read More
Purpose: Homozygous ABCA1 gene mutation causes Tangier disease (TD). The effects reported in heterozygous state regard plasma HDL, cell cholesterol efflux and coronary artery disease. We investigated whether in vitro replicative skin fibroblast senescence shown in TD proband (Hom), his father (Het), and in a healthy control might be induced in a "gene-dosage way". Read More
A kindred affected with fish eye disease (FED) from Oklahoma is reported. Two probands with corneal opacification had mean levels of high-density lipoprotein (HDL) cholesterol (C), apolipoprotein (apo) A-I, and apoA-I in very large alpha-1 HDL particles that were 9%, 17%, and 5% of normal, whereas their parents and 1 sibling had values that were 61%, 77%, and 72% of normal. The probands had no detectable lipoprotein-X, and had mean low-density lipoprotein cholesterol (LDL-C) and triglyceride levels that were elevated. Read More
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. Read More
CONTEXT AND OBJECTIVE Metabolic syndrome is characterized by clustering of cardiovascular risk factors such as obesity, dyslipidemia, insulin resistance, hyperinsulinemia, glucose intolerance and arterial hypertension. The aim of this study was to estimate the probability of clustering and the combination pattern of three or more metabolic syndrome components in a rural Brazilian adult population. DESIGN AND SETTING This was a cross-sectional study conducted in two rural communities located in the Jequitinhonha Valley, Minas Gerais, Brazil. Read More
Objectives: This study sought to examine the relationship between baseline and on-study apolipoproteins (apo) A-1 and B and lipoprotein(a) [Lp(a)] levels and the development of subsequent cardiovascular (CV) events in the AIM-HIGH (Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglyceride and Impact on Global Health Outcomes) trial.
Background: Niacin has been reported to lower apoB and Lp(a) and to raise apoA-1.
Methods: Individuals with CV disease and low baseline levels of high-density lipoprotein cholesterol were randomized to simvastatin plus placebo or simvastatin, plus extended-release niacin ([ERN], 1,500 to 2,000 mg/day), with ezetimibe added as needed, in both groups, to maintain an on-treatment low-density lipoprotein cholesterol in the range of 40 to 80 mg/dl. Read More
Introduction: Epidemiologic evidence suggests that tomato-based products could reduce the risk of cardiovascular diseases. One of the main cardiovascular risk factors is low levels of high-density lipoprotein cholesterol (HDL-C). This study aimed to prospectively evaluate the effect of tomato consumption on HDL-C levels. Read More
Lecithin-cholesterol acyltransferase (LCAT) is an enzyme involved in maintaining cholesterol homeostasis. In familial LCAT deficiency (FLD), abnormal lipid deposition causes renal injury and nephrotic syndrome, frequently progressing to ESRD. Here, we describe a 63-year-old Japanese woman with no family history of renal disease who presented with nephrotic syndrome. Read More
Background: The prevalence of severe obesity in children and adolescents is increasing. However, little is known about cardiometabolic risk factors and quality of life of children with severe obesity.Therefore, the aim of this study was to assess the demographic characteristics and the prevalence of cardiometabolic risk factors and quality of life in severely obese children and adolescents undergoing intensive inpatient treatment for obesity. Read More
Background: Low high-density lipoprotein (HDL) levels are major predictors of cardiovascular (CV) events, even in patients on statin treatment with low-density lipoprotein (LDL) at target. In animal models HDLs protect LDL from oxidation and blunt platelet activation. Our study aimed to examine whether HDL levels are related to in vivo oxidative stress and platelet activation, as determinants of atherothrombosis. Read More
Background And Objective: Metabolic syndrome (MS) frequency is growing and diet has an important influence on its evolution. Our objective was to study the effect of 3 sources of polyunsaturated fatty acids on MS parameters in humans.
Patients And Method: The MS was diagnosed according to the International Diabetes Federation. Read More
Few studies have addressed the delivery of lipoprotein-derived cholesterol to the adrenals for steroid production in humans. While there is evidence against a role for low-density lipoprotein (LDL), it is unresolved whether high density lipoprotein (HDL) contributes to adrenal steroidogenesis. To study this, steroid hormone profiles in urine were assessed in male subjects suffering from functional mutations in ATP binding cassette transporter A1 (ABCA1) (n = 24), lecithin:cholesterol acyltransferase (LCAT) (n = 40), as well as in 11 subjects with low HDL cholesterol (HDL-C) without ABCA1/LCAT mutations. Read More
Background: The Mexican population and others with Amerindian heritage exhibit a substantial predisposition to dyslipidemias and coronary heart disease. Yet, these populations remain underinvestigated by genomic studies, and to date, no genome-wide association (GWA) studies have been reported for lipids in these rapidly expanding populations.
Methods And Findings: We performed a two-stage GWA study for hypertriglyceridemia and low high-density lipoprotein cholesterol (HDL-C) in Mexicans (n=4361), and identified a novel Mexican-specific genome-wide significant locus for serum triglycerides (TGs) near the Niemann-Pick type C1 protein gene (p=2. Read More
A 61-year-old white man of European ancestry with significant coronary heart disease since age 42 years and marked high-density lipoprotein (HDL) deficiency (HDL cholesterol 1 mg/dL) was evaluated. His fasting low-density lipoprotein cholesterol level was 42 mg/dL, and his triglycerides were 417 mg/dL on therapy with rosuvastatin 40 mg/day, ezetimibe 10 mg/day, fenofibrate 145 mg/day, and extended-release niacin 2 g/day. Further analysis of his plasma revealed an apolipoprotein (apo) A-I level of 23. Read More
Background: Lecitin cholesterol acyltransferase (LCAT) deficiency comprises a group of rare disorders related to HDL metabolism. These disorders are characterized by ophthalmologic, hematologic, and renal findings. Case diagnosis/treatment: A 15-year-old female who presented with nephrotic syndrome and hypertension was diagnosed with LCAT deficiency by renal biopsy and LCAT enzyme activity. Read More
Clin Nutr 2013 Oct 12;32(5):797-804. Epub 2012 Dec 12.
Department of Preventive Medicine and Public Health, School of Medicine, University of Navarra, C/Irunlarrea, 1, 31008 Pamplona, Navarra, Spain; Department of Cardiology and Cardiac Surgery, University Clinic of Navarra, Avenida Pio XII, 36, 31008 Pamplona, Navarra, Spain.
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. Read More
Objective: Carriers of a functional mutation in LCAT, encoding lecithin:cholesterol acyl transferase, are exposed to lifelong low high-density lipoprotein cholesterol (HDL-c) levels. We investigated whether LCAT mutation carriers have increased arterial stiffness as a marker of cardiovascular disease and whether arterial stiffness was associated with carotid wall thickening.
Methods: We assessed 45 carriers of LCAT mutations (mean age ± SD 46 ± 13 yrs) and 45 age-matched controls. Read More
Patients with extremely low high-density lipoprotein-cholesterol (HDL-C) pose distinct challenges to clinical diagnosis and management. Confirmation of HDL-C levels below 20 mg/dl in the absence of severe hypertriglyceridemia should be followed by evaluation for secondary causes, such as androgen use, malignancy, and primary monogenic disorders, namely, apolipoprotein A-I mutations, Tangier disease, and lecithin-cholesterol acyltransferase deficiency. Global cardiovascular risk assessment is a critical component of comprehensive evaluation, although the association between extremely low HDL-C levels and atherosclerosis remains unclear. Read More
Cardiovascular disease due to atherosclerosis is a leading cause of death around the world, including Singapore. Current treatment strategies primarily target low-density lipoprotein (LDL) cholesterol levels. Low levels of high-density lipoprotein (HDL) cholesterol and high triglyceride (TG) levels have been shown to increase the risk of coronary heart disease, but the clinical benefits of raising low HDL cholesterol have only been proven in a limited number of studies. Read More
The objective of the study was the characterization of ABCA1 gene mutations in 10 patients with extremely low HDL-cholesterol. Five patients (aged 6 months to 76 years) presented with splenomegaly and thrombocytopenia suggesting the diagnosis of Tangier disease (TD). Three of them were homozygous for novel mutations either in intron (c. Read More
Tangier disease is one of the most severe forms of familial high-density lipoprotein (HDL) deficiency. Since its discovery it has been diagnosed in about 100 patients and is characterized by severe plasma deficiency or absence of HDL, apolipoprotein A-I (apoA-I, the major HDL apolipoprotein) and by accumulation of cholesteryl esters in many tissues throughout the body. The biochemical signs of this condition are plasma HDL concentrations less than 5 mg/dL, low total plasma cholesterol (below 150 mg/dL), and normal or high plasma triglycerides. Read More
Diabetes is a significant risk factor for the development of cardiovascular disease (CVD), particularly in the presence of high blood pressure, poor glycaemic control and high total cholesterol. While efforts to control blood pressure or blood glucose beyond levels considered 'normal' in patients with diabetes have not produced the expected reduction in CVD, treatment with statins to reduce levels of low-density lipoprotein cholesterol (LDL-C) has been much more successful. However, many patients with diabetes who receive statins (even at high doses) remain at significant residual risk of CVD due to the presence of atherogenic dyslipidaemia. Read More
A number of epidemiological and clinical studies have demonstrated that plasma high-density lipoprotein (HDL) level is a strong inverse predictor of cardiovascular events. HDL is believed to retard the formation of atherosclerotic lesions by removing excess cholesterol from cells and preventing endothelial dysfunction. Lecithin cholesterol acyltransferase (LCAT) plays a central role in the formation and maturation of HDL, and in the intravascular stage of reverse cholesterol transport: a major mechanism by which HDL modulates the development and progression of atherosclerosis. Read More
Background: Lecithin:cholesterol acyltransferase (LCAT) is responsible for cholesterol esterification in plasma. Mutations of LCAT gene cause familial LCAT deficiency, a metabolic disorder characterized by hypoalphalipoproteinemia. Apolipoprotein B (apoB) is the main protein component of very-low-density lipoproteins and low-density lipoprotein (LDL). Read More