Association of Prepregnancy BMI, Gestational Weight Gain, and Child Birth Weight with Metabolic Dysfunction in Children and Adolescents with Obesity.

OBJECTIVES: Previous studies have reported that maternal prepregnancy body mass index (BMI), gestational weight gain (GWG), and child birth weight are positively associated with metabolic dysfunction (a broader term than metabolic syndrome) in children and adolescents. Physical activity habits may play a role in reducing these risk factors. The objectives of this study were to investigate the association of prepregnancy BMI, GWG, child birth weight, physical activity, and sedentary time with metabolic dysfunction in a cohort of children and adolescents with obesity. METHODS: Participants (N = 117; 53% Hispanic) were children and adolescents, aged 8 to 17 years, with obesity. Fasting serum glucose, insulin, and a complete lipid profile were obtained. Body weight, height, waist circumference, and blood pressure were measured. A self-reported survey assessed prepregnancy BMI, GWG, child birth weight, physical activity, and sedentary time. The χ2 test and the Mantel-Haenzel test statistic were used to examine the differences in proportions for the outcome of metabolic dysfunction. RESULTS: In this sample, 76.9% of children and adolescents had metabolic dysfunction. Prepregnancy BMI and GWG were not associated with metabolic dysfunction. Child birth weight and sedentary behavior were positively correlated (P = 0.033 and P = 0.015, respectively) with a diagnosis of metabolic dysfunction. Physical activity levels were not associated with metabolic dysfunction. Hispanic and non-Hispanic youth were similar for all risk factors. CONCLUSIONS: Contrary to previous studies, prepregnancy BMI and GWG were not correlated with metabolic dysfunction. These findings support the need for lifestyle interventions, particularly in reducing sedentary behaviors, in obese children and adolescents.

Cold-Activated Brown Adipose Tissue is Associated with Less Cardiometabolic Dysfunction in Young Adults with Obesity.

OBJECTIVE: This study aimed to test the hypothesis that young adults with obesity and cold-activated brown adipose tissue (BAT) are less likely to have metabolic dysfunction (dyslipidemia, insulin resistance, and hypertension) than those without cold-activated BAT. Previous studies have noted a potentially protective effect of BAT and higher adiponectin/leptin ratios, but they have acknowledged that the clinical implications of these findings remain uncertain. METHODS: Twenty-one females and twenty-three males with obesity (BMI ≥ 30 kg/m2 ) underwent a 2-hour cooling protocol before 18 F-fluorodeoxyglucose (18 F-FDG)-positron emission tomography/x-ray computed tomography scan to determine the prevalence, volume, and 18 F-FDG uptake of cold-activated BAT. RESULTS: Cold-activated BAT was identified in 43% of participants (11 female, 8 male); females had greater 18 F-FDG uptake. Those with cold-activated BAT had a lesser degree of metabolic dysfunction. Cold-activated BAT volume correlated with triglycerides (inversely) and adiponectin (concordantly). Body-mass-adjusted cold-activated BAT activity correlated with high-density lipoprotein cholesterol (concordantly). Males with cold-activated BAT had lower leptin and higher adiponectin/leptin ratio. CONCLUSIONS: A high prevalence of cold-activated BAT was found in the study participants. BAT could be important in decreasing metabolic dysfunction among young adults with obesity, making it a potential target for treating metabolically unhealthy obesity.

Weight and Metabolic Outcomes 12 Years after Gastric Bypass.

BACKGROUND: Few long-term or controlled studies of bariatric surgery have been conducted to date. We report the 12-year follow-up results of an observational, prospective study of Roux-en-Y gastric bypass that was conducted in the United States. METHODS: A total of 1156 patients with severe obesity comprised three groups: 418 patients who sought and underwent Roux-en-Y gastric bypass (surgery group), 417 patients who sought but did not undergo surgery (primarily for insurance reasons) (nonsurgery group 1), and 321 patients who did not seek surgery (nonsurgery group 2). We performed clinical examinations at baseline and at 2 years, 6 years, and 12 years to ascertain the presence of type 2 diabetes, hypertension, and dyslipidemia. RESULTS: The follow-up rate exceeded 90% at 12 years. The adjusted mean change from baseline in body weight in the surgery group was -45.0 kg (95% confidence interval [CI], -47.2 to -42.9; mean percent change, -35.0) at 2 years, -36.3 kg (95% CI, -39.0 to -33.5; mean percent change, -28.0) at 6 years, and -35.0 kg (95% CI, -38.4 to -31.7; mean percent change, -26.9) at 12 years; the mean change at 12 years in nonsurgery group 1 was -2.9 kg (95% CI, -6.9 to 1.0; mean percent change, -2.0), and the mean change at 12 years in nonsurgery group 2 was 0 kg (95% CI, -3.5 to 3.5; mean percent change, -0.9). Among the patients in the surgery group who had type 2 diabetes at baseline, type 2 diabetes remitted in 66 of 88 patients (75%) at 2 years, in 54 of 87 patients (62%) at 6 years, and in 43 of 84 patients (51%) at 12 years. The odds ratio for the incidence of type 2 diabetes at 12 years was 0.08 (95% CI, 0.03 to 0.24) for the surgery group versus nonsurgery group 1 and 0.09 (95% CI, 0.03 to 0.29) for the surgery group versus nonsurgery group 2 (P<0.001 for both comparisons). The surgery group had higher remission rates and lower incidence rates of hypertension and dyslipidemia than did nonsurgery group 1 (P<0.05 for all comparisons). CONCLUSIONS: This study showed long-term durability of weight loss and effective remission and prevention of type 2 diabetes, hypertension, and dyslipidemia after Roux-en-Y gastric bypass. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.).

Expression of Metabolic Syndrome in Women with Severe Obesity.

BACKGROUND: The prevalence of metabolic syndrome (MetS) generally rises with increasing adiposity, but tends to plateau at the highest levels of body mass index (BMI) with some individuals, even with severe obesity, expressing few or no components of MetS. We examined factors associated with the expression of MetS in severely obese women participating in a large observational study. METHODS: Anthropometrics, including Heath equation-adjusted bioimpedance-determined fat-free mass (FFM) and fat mass (FM), lipids and related laboratory measurements, resting energy expenditure (REE), and respiratory quotient (RQ), were studied in 949 women with severe obesity. RESULTS: Even though the mean BMI was 45.7 kg/m2 and all participants met MetS criteria for increased waist circumference, 30% of subjects did not have MetS. Unadjusted FM (P = 0.0011), FFM (P < 0.0001), and REE (P < 0.0001) were greater in the women with MetS. Surprisingly, in multivariate logistic regression FFM was positively associated with MetS (P = 0.0002), while FM was not (P = 0.89). Moreover, FFM, not FM, was significantly associated with all five components of MetS except for triglyceride levels. REE and RQ were higher in those with MetS, and REE was strongly associated with multiple components of MetS. CONCLUSIONS: In women with severe obesity, higher FFM and REE were paradoxically associated with increased rather than decreased risk of MetS, while FFM-adjusted FM was unrelated to MetS.

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

BACKGROUND: Low-density lipoprotein particle concentration (LDL-P) is generally more predictive of clinical cardiovascular endpoints than LDL cholesterol (LDL-C). Few studies have directly compared multiple LDL-P methods, particularly with ultracentrifugation. OBJECTIVE: Examine comparability and precision of 4 LDL-P methods. METHODS: We divided serum from 48 subjects into blinded triplicates and measured LDL-P in 3 separate laboratories by 4 methods: ultracentrifugation (reference method), a novel electrophoretic method, and nuclear magnetic resonance spectroscopy (NMR) by 2 independent methods: a 400 MHz Vantera(®) instrument supplied by Liposcience (LS-NMR) and operated at ARUP Laboratories, and a 600 MHz Bruker instrument (ASCEND 600) operated at Health Diagnostic Laboratory (HD-NMR). RESULTS: Of the 4 methods, ultracentrifugation was the most precise and LS-NMR the least; the latter had a significantly greater CV (p < 0.0001) as compared with all 3 of the other methods, although all CVs were clinically acceptable. The electrophoretic method showed similar precision to ultracentrifugation, while HD-NMR was intermediate. The HD-NMR had the slope closest to 1 (0.90, 95% CI 0.71 to 1.09) and the intercept closest to 0 (-48, -353 to 256) compared to the ultracentrifugation method in Deming regression models. While the two NMR methods correlated well (r = 0.95) with each other and had a slope equivalent to 1 (1.08, 0.98 to 1.19), their intercept in Deming regression excluded 0 (194, 53 to 335) indicating a vertical shift between the two methods. CONCLUSIONS: This LDL-P method comparison may prove useful for future research and clinical applications.

LDL and HDL transfer rates across peripheral microvascular endothelium agree with those predicted for passive ultrafiltration in humans.

The mechanisms by which LDLs and HDLs cross the vascular endothelium from plasma into interstitial fluid are not understood, and have never been studied in humans in vivo. We determined whether the plasma-to-lymph clearance rates of LDL and HDL conform with those predicted by passive ultrafiltration through intercellular pores, or if it is necessary to invoke an active process such as receptor-mediated transcytosis. Plasma and afferent peripheral lymph were collected under steady-state conditions from 30 healthy men, and assayed for seven globular proteins of molecular radii 2.89-8.95 nm, complement C3, and apo AI, apo AII, and apo B. Plasma-to-lymph clearance rates of the seven proteins fitted the relation expected for molecules of their size when transported through two populations of pores of radius 4.95 and 20.1 nm. The same model parameters were then found to accurately predict the clearance rates of both HDL and LDL. The apparent clearance of complement C3, previously shown to be secreted by cultured endothelium, exceeded that predicted by the model. We conclude that the transport of HDL and LDL from plasma into interstitial fluid across the peripheral vascular endothelium in healthy humans can be explained by ultrafiltration without invoking an additional active process such as transcytosis.

Hyperlipoproteinemia type 3: the forgotten phenotype.

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

An in-silico model of lipoprotein metabolism and kinetics for the evaluation of targets and biomarkers in the reverse cholesterol transport pathway.

High-density lipoprotein (HDL) is believed to play an important role in lowering cardiovascular disease (CVD) risk by mediating the process of reverse cholesterol transport (RCT). Via RCT, excess cholesterol from peripheral tissues is carried back to the liver and hence should lead to the reduction of atherosclerotic plaques. The recent failures of HDL-cholesterol (HDL-C) raising therapies have initiated a re-examination of the link between CVD risk and the rate of RCT, and have brought into question whether all target modulations that raise HDL-C would be atheroprotective. To help address these issues, a novel in-silico model has been built to incorporate modern concepts of HDL biology, including: the geometric structure of HDL linking the core radius with the number of ApoA-I molecules on it, and the regeneration of lipid-poor ApoA-I from spherical HDL due to remodeling processes. The ODE model has been calibrated using data from the literature and validated by simulating additional experiments not used in the calibration. Using a virtual population, we show that the model provides possible explanations for a number of well-known relationships in cholesterol metabolism, including the epidemiological relationship between HDL-C and CVD risk and the correlations between some HDL-related lipoprotein markers. In particular, the model has been used to explore two HDL-C raising target modulations, Cholesteryl Ester Transfer Protein (CETP) inhibition and ATP-binding cassette transporter member 1 (ABCA1) up-regulation. It predicts that while CETP inhibition would not result in an increased RCT rate, ABCA1 up-regulation should increase both HDL-C and RCT rate. Furthermore, the model predicts the two target modulations result in distinct changes in the lipoprotein measures. Finally, the model also allows for an evaluation of two candidate biomarkers for in-vivo whole-body ABCA1 activity: the absolute concentration and the % lipid-poor ApoA-I. These findings illustrate the potential utility of the model in drug development.

Lipoprotein remodeling generates lipid-poor apolipoprotein A-I particles in human interstitial fluid.

Although much is known about the remodeling of high density lipoproteins (HDLs) in blood, there is no information on that in interstitial fluid, where it might have a major impact on the transport of cholesterol from cells. We incubated plasma and afferent (prenodal) peripheral lymph from 10 healthy men at 37°C in vitro and followed the changes in HDL subclasses by nondenaturing two-dimensional crossed immunoelectrophoresis and size-exclusion chromatography. In plasma, there was always initially a net conversion of small pre-ß-HDLs to cholesteryl ester (CE)-rich α-HDLs. By contrast, in lymph, there was only net production of pre-ß-HDLs from α-HDLs. Endogenous cholesterol esterification rate, cholesteryl ester transfer protein (CETP) concentration, CE transfer activity, phospholipid transfer protein (PLTP) concentration, and phospholipid transfer activity in lymph averaged 5.0, 10.4, 8.2, 25.0, and 82.0% of those in plasma, respectively (all P < 0.02). Lymph PLTP concentration, but not phospholipid transfer activity, was positively correlated with that in plasma (r = +0.63, P = 0.05). Mean PLTP-specific activity was 3.5-fold greater in lymph, reflecting a greater proportion of the high-activity form of PLTP. These findings suggest that cholesterol esterification rate and PLTP specific activity are differentially regulated in the two matrices in accordance with the requirements of reverse cholesterol transport, generating lipid-poor pre-ß-HDLs in the extracellular matrix for cholesterol uptake from neighboring cells and converting pre-ß-HDLs to α-HDLs in plasma for the delivery of cell-derived CEs to the liver.

Vitamin D dependent effects of APOA5 polymorphisms on HDL cholesterol.

OBJECTIVES: Vitamin D and serum lipid levels are risk factors for cardiovascular disease. We sought to determine if vitamin D (25OHD) interacts at established lipid loci potentially explaining additional variance in lipids. METHODS: 1060 individuals from Utah families were used to screen 14 loci for SNPs potentially interacting with dietary 25OHD on lipid levels. Identified putative interactions were evaluated for (1) greater effect size in subsamples with winter measures, (2) replication in an independent sample, and (3) lack of gene-environment interaction for other correlated dietary factors. Maximum likelihood models were used to evaluate interactions. The replicate sample consisted of 2890 individuals from the Family Heart Study. Putative 25OHD receptor binding site modifying SNPs were identified and allele-specific, 25OHD-dependent APOA5 promoter activity examined using luciferase expression assays. An additional sample with serum 25OHD measures was analyzed. RESULTS: An rs3135506-25OHD interaction influencing HDL-C was identified. The rs3135506 minor allele was more strongly associated with low HDL-C in individuals with low winter dietary 25OHD in initial and replicate samples (p=0.0003 Utah, p=0.002 Family Heart); correlated dietary factors did not explain the interaction. SNP rs10750097 was identified as a putative causative polymorphism, was associated with 25OHD-dependent changes in APOA5 promoter activity in HEP3B and HEK293 cells (p<0.01), and showed similar interactions to rs3135506 in family cohorts. Linear interactions were not significant in samples with serum 25OHD measures; however, genotype-specific differences were seen at deficient 25OHD levels. CONCLUSIONS: A 25OHD receptor binding site modifying APOA5 promoter polymorphism is associated with lower HDL-C in 25OHD deficient individuals.

Validity and reliability of perinatal biomarkers of adiposity after storage as dried blood spots on paper.

OBJECTIVE: To validate use of chip-based immunoaffinity capillary electrophoresis on dried blood spot samples (DBSS) to measure obesity-related hormones. METHODS: Chip-based immunoaffinity capillary electrophoresis was used to measure adiponectin, leptin and insulin in capillary serum and DBSS in pregnant women and infant heelstick at birth and six weeks. Concordance of measurements was determined with Pearson's correlation and Bland-Altman plots. RESULTS: We report high concordance between results obtained from serum and DBSS. CONCLUSIONS: Ease of sample collection and storage makes DBSS an optimal method for use in studies involving neonates and young children, as well as studies conducted in areas where freezer storage is not available.

Secretion of adipokines by human adipose tissue in vivo: partitioning between capillary and lymphatic transport.

Peptides secreted by adipose tissue (adipokines) may enter blood via capillaries or lymph. The relative importance of these pathways for a given adipokine might influence its biological effects. Because this has not been studied in any species, we measured the concentrations of seven adipokines and eight nonsecreted proteins in afferent peripheral lymph and venous plasma from 12 healthy men. Data for nonsecreted proteins were used to derive indices of microvascular permeability, which in conjunction with the molecular radii of the adipokines were used to estimate the amounts leaving the tissue via capillaries. Transport rates via lymph were estimated from the lymph adipokine concentrations and lymph flow rates and total transport (secretion) as the sum of this and capillary transport. Concentrations of nonsecreted proteins were always lower in lymph than in plasma. With the exception of adiponectin, adipokine concentrations were always higher in lymph (P < 0.01). Leptin and MCP-1 were secreted at the highest rates (means: 43 µg/h or 2.7 nmol/h and 32 µg/h or 2.4 nmol/h, respectively). IL-6 and MCP-1 secretion rates varied greatly between subjects. The proportion of an adipokine transported via lymph was directly related to its molecular radius (r(s) = +0.94, P = 0.025, n = 6), increasing from 14 to 100% as the radius increased from 1.18 (IL-8) to 3.24 nm (TNFα). We conclude that the lymph/capillary partitioning of adipokines is a function of molecular size, which may affect both their regional and systemic effects in vivo. This finding may have implications for the physiology of peptides secreted by other tissues.

Altered composition of triglyceride-rich lipoproteins and coronary artery disease in a large case-control study.

BACKGROUND: Traditional beta-quantification of plasma lipoproteins by ultracentrifugation separates triglyceride-rich lipoproteins (TGRL) from higher density lipoproteins. The cholesterol in the TGRL fraction is referred to as measured very low-density lipoprotein cholesterol (VLDL-C) recognizing that other TGRL may be present. The measured VLDL-C to total plasma triglyceride (VLDL-C/TG) has long been considered an index of average TGRL composition with abnormally high VLDL-C/TG ratios (>or=0.30 with TG>150mg/dL) indicative of atherogenic remnant accumulation (type III hyperlipidemia). However, virtually no reports are available which examine potential associations between CAD and VLDL-C/TG at the lower end of the spectrum. METHODS AND RESULTS: We performed ultracentrifugation in 1170 cases with premature-onset, familial CAD and 1759 population-based controls and examined the VLDL-C/TG ratio as an index of TGRL composition. As expected, we found very high CAD risk associated with severe type III hyperlipidemia (OR 10.5, p=0.02). Unexpectedly, however, we found a robust, graded, and independent association between CAD risk and lower than average VLDL-C/TG ratios (p<0.0001 as ordered categories or as a continuous variable). Among those in the lowest VLDL-C/TG category (a ratio <0.12), CAD risk was clearly increased (OR 4.5, 95% CI 2.9-6.9) and remained significantly elevated in various subgroups including those with triglycerides below 200mg/dl, in males and females separately, as well as among those with no traditional CAD risk factors (OR 5.8, 95% CI 1.5-22). Significant compositional differences by case status were confirmed in a subset whose samples were re-spun with measurement of lipids and apolipoprotein B (apo B) in each subfraction. CONCLUSIONS: We found a strong, graded, independent, and robust association between CAD and lower VLDL-C/TG ratios. We consider this a novel, hypothesis-generating observation which will hopefully generate additional future studies to provide confirmation and further insight into potential mechanisms.

Mass kinetics of apolipoprotein A-I in interstitial fluid after administration of intravenous apolipoprotein A-I/lecithin discs in humans.

Apolipoprotein kinetics are customarily determined by modeling time curves of specific radioactivity or isotopic enrichment in plasma after intravenous infusion of radiolabeled lipoproteins or stable isotope-enriched amino acids. However, this provides no information on the fractional rate of transfer of the apolipoprotein from plasma to interstitial fluid (k(p-if)) or its mean residence time in interstitial fluid (MRT(if)). To determine these parameters for a pharmacologic dose of exogenous apolipoprotein A-I (apoA-I) given intravenously as apoA-I/lecithin discs, we measured apoA-I in plasma and prenodal leg lymph in five healthy men before, during, and after a 4 h infusion at 10 mg/kg/h. ApoA-I concentrations in plasma and lymph were modeled by linear compartmental models (SAAM II version 1.1), using lymph albumin to adjust for the effects of variations in lymph flow rate. k(p-if) averaged 0.75%/h (range, 0.33-1.32), and MRT(if) averaged 29.1 h (14.1-40.0). Neither parameter was correlated with the distribution volume (57-105 ml/kg) or the fractional elimination rate (1.44-2.91%/h) of apoA-I, determined by modeling plasma apoA-I concentration alone. Although used here to study the mass kinetics of apoA-I, if combined with infusion of a tracer, analysis of lymph could also expand the modeling of endogenous apolipoprotein kinetics.

Effects of intravenous apolipoprotein A-I/phosphatidylcholine discs on paraoxonase and platelet-activating factor acetylhydrolase in human plasma and tissue fluid.

We have previously shown that intravenous apolipoprotein (apo) A-I/phosphatidylcholine (apo A-I/PC) discs increase plasma high-density lipoprotein (HDL) concentration in humans. We have now studied the associated changes in two enzymes, paraoxonase (PON) and platelet-activating factor acetylhydrolase (PAF-AH) that are carried in whole or in part by HDLs, and are thought to influence atherogenesis by hydrolyzing oxidized phospholipids in lipoproteins. Apo A-I/PC discs (40 mg/kg over 4 h) were infused into eight healthy males. Although plasma apo A-I and HDL cholesterol increased on average by 178 and 158%, respectively, plasma total PON and total PAF-AH concentrations did not rise. By the end of the infusion, HDL-associated PAF-AH had increased by 0.56 +/- 0.14 microg/mL (mean +/- S.D., P < 0.01), and nonHDL-associated PAF-AH had decreased by 0.84 +/- 0.11 microg/mL (P < 0.05). These changes were accompanied by an increase in the HDL-associated PAF-AH/apo A-I ratio from 0.19 to 0.35 (P < 0.05), and by a decrease in the nonHDL-associated PAF-AH/apo B ratio from 2.1 to 1.4 (P < 0.05). No changes in PON or PAF-AH concentrations were detected in prenodal lymph (tissue fluid), collected continuously from the leg. Our results show that the total concentrations of PON and PAF-AH in plasma are uninfluenced by plasma HDL concentration. PAF-AH transfers readily between HDLs and LDLs in vivo, and its distribution between them is determined partly by their relative concentrations and partly by HDL composition.

Variations in lipid and apolipoprotein concentrations in human leg lymph: effects of posture and physical exercise.

We studied the variations in the concentrations of cholesterol, triglycerides, phospholipids, apolipoproteins (apos) (A-I, A-II, B, C-III, E), free glycerol and albumin in human prenodal leg lymph during the 24 h cycle. Lymph was collected continuously for up to 96 h from nine healthy males on a low-fat isocaloric diet. In three free-living subjects, all lipid and apolipoprotein concentrations underwent synchronous variations, rising during the night and decreasing during the day. In three subjects who remained in supine rest for 48 h, the amplitude of circadian variation was much smaller. In three who alternated periods of supine rest with upright exercise, the highest concentrations occurred during rest. Lipid, apolipoprotein and albumin concentrations were inversely related to lymph flow rate. Free glycerol, much of which in tissue fluid is derived from local adipocytes, did not follow this pattern. On multiple regression, concentrations in lymph were related independently to the corresponding concentration in plasma (positive) and to lymph flow rate (negative) or lymph albumin concentration (positive). These results show that lipoprotein concentrations in human tissue fluid are determined only partly by their concentrations in plasma. They are also strongly affected by hemodynamic factors via their effects on fluid transport.

Association of coronary heart disease with pre-beta-HDL concentrations in Japanese men.

BACKGROUND: In individuals heterozygous for ABCA1 transporter mutations, defective reverse cholesterol transport (RCT) causes low HDL-cholesterol and premature coronary heart disease (CHD). However, the extent to which impaired RCT underlies premature CHD in others with low HDL-cholesterol is not known. The primary acceptors of cell cholesterol are a minor subclass of lipid-poor pre-beta-HDLs. These are generated during remodeling of alpha-HDLs, which account for almost all HDL-cholesterol. We studied the strength of the association of CHD with pre-beta-HDL concentrations in Japanese men. METHODS: Blood was collected from 42 men with clinical CHD and 44 healthy controls 40-70 years of age. Pre-beta-HDL was assayed by crossed immunoelectrophoresis. RESULTS: Cases had lower HDL-cholesterol (-23%), total apolipoprotein A-I (-26%), and pre-beta-HDL (-55%; all P <0.001) concentrations; lower pre-beta-HDL:alpha-HDL ratios (-45%; P <0.001); and higher plasma triglycerides (20%; P <0.03) than the controls. On stepwise logistic regression, CHD was associated most strongly with pre-beta-HDL concentrations. On ROC analysis, pre-beta-HDL concentration discriminated between cases and controls better than any other lipoprotein measurement. When plasma was incubated for 16 h at 37 degrees C, mean (SD) pre-beta-HDL increased by 47 (36)% in controls, but was unchanged in cases (group difference, P <0.001). CONCLUSIONS: Our results suggest that inefficient RCT, secondary to a low pre-beta-HDL concentration and production rate in plasma, contributes to premature CHD in Japanese men with low HDL-cholesterol.

A novel LCAT mutation (Phe382-->Val) in a kindred with familial LCAT deficiency and defective apolipoprotein B-100.

We studied a four-generation family (17 subjects) with familial lecithin:cholesterol acyltransferase (LCAT) deficiency. A 30-year-old Caucasian male with corneal clouding and HDL cholesterol <0.1 mmol/l was a compound heterozygote for a novel mutation (Phe(382)-->Val), a previously reported mutation (Thr321-->Met) and a common variant (Thr208-->Ser) of the gene. Immunoreactive LCAT concentration (1.2 microg/ml), alpha-LCAT activity (13 nmol/ml per h) and cholesterol esterification rate (CER) (14 nmol/ml per h) in his plasma were, respectively, 14, 8 and 14% of the mean values in healthy subjects. The proband and 13 of his relatives also had familial defective apo B (FDB, Arg3500-->Gln). Six subjects had LCAT Phe382-->Val in combination with FDB. Plasma lipoprotein(a) (Lp(a)) was 24 nmol/l in the proband and 46-211 nmol/l in his father and siblings, consistent with expression of the 16 kringle 4 isoform. The proband had no signs of coronary heart disease (CHD), but his father, a paternal uncle and a female cousin had CHD before age 38 years.

Effects of intravenous apolipoprotein A-I/phosphatidylcholine discs on LCAT, PLTP, and CETP in plasma and peripheral lymph in humans.

OBJECTIVE: We have previously shown that intravenous apolipoprotein A-I/phosphatidylcholine (apoA-I/PC) discs increase plasma pre-beta HDL concentration and stimulate reverse cholesterol transport (RCT) in humans. We have now investigated the associated changes in the following 3 HDL components that play key roles in RCT: lecithin:cholesterol acyltransferase (LCAT), cholesteryl ester transfer protein (CETP), and phospholipid transfer protein (PLTP). METHODS AND RESULTS: apoA-I/PC discs (40 mg/kg over 4 hours) were infused into 8 healthy men. Samples of blood and prenodal peripheral lymph were collected for 24 to 48 hours. At 12 hours, plasma LCAT concentration had increased by 0.40+/-0.90 mg/L (+7.8%; mean+/-SD; P<0.05), plasma cholesterol esterification rate by 29.0+/-9.0 nmol/mL per h (+69.5%; P<0.01), plasma CETP concentration by 0.5+/-0.2 mg/L (+29.7%; P<0.01), and plasma PLTP activity by 1.45+/-0.67 micromol/mL per h (+23.9%; P<0.01). In contrast, plasma PLTP concentration had decreased by 4.4+/-2.7 mg/L (-44.8%; P<0.01). The changes in PLTP were accompanied by alterations in the relative proportions of large lipoproteins containing inactive PLTP and small particles containing PLTP of high specific activity. No changes were detected in peripheral lymph. CONCLUSIONS: Nascent HDL secretion may induce changes in PLTP, LCAT, and CETP that promote RCT by catalyzing pre-beta HDL production, cholesterol esterification in HDLs, and cholesteryl ester transfer from HDLs to other lipoproteins.