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Background: The accurate measurement of blood lipids and lipoproteins is crucial for the clinical management of atherosclerotic disease risk. Despite progress in standardization, there are still significant variations in pre-analytical requirements, methods, nomenclature, and reporting work flows., Content: The guidance document aims to improve standardization of clinical lipid testing work flows. It provides recommendations for the components of the lipid panel, fasting requirements, reporting of results, and specific recommendations for non-high-density lipoprotein cholesterol (non-HDL-C), low-density lipoprotein cholesterol (LDL-C), lipoprotein(a) [Lp(a)], apolipoprotein B (apo B), point-of-care lipid testing, and LDL subfraction testing., Summary: Lipid panels should always report non-HDL-C and LDL-C calculations if possible. Fasting is not routinely required except in specific cases. Modern equations should be utilized for LDL-C calculation. These equations allow for LDL-C reporting at elevated concentrations of triglycerides and obviate the need for direct measured LDL-C in most cases., (© Association for Diagnostics & Laboratory Medicine 2024. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Competing Interests: Disclosures R.A. Hegele reports consulting fees from Akcea/Ionis, Amgen, HLS Therapeutics, Novartis, Pfizer, Regeneron, Sanofi, and Ultragenyx. The other authors report no conflicts.

Background: Lipoprotein subfraction concentrations have been shown to change as gestation progresses in resource-rich settings. The objective of the current study was to evaluate the impact of pregnancy on different-sized lipoprotein particle concentrations and compositions in a resource-poor setting., Method: Samples were collected from pregnant women in rural Gambia at enrollment (8-20 weeks), 20 weeks, and 30 weeks of gestation. Concentrations of different-sized high-density, low-density, and triglyceride-rich lipoprotein particles (HDL, LDL, and TRL, respectively) were measured by nuclear magnetic resonance in 126 pooled plasma samples from a subset of women. HDL was isolated and the HDL proteome evaluated using mass spectroscopy. Subfraction concentrations from women in The Gambia were also compared to concentrations in women in the U.S. in mid gestation., Results: Total lipoprotein particles and all-sized TRL, LDL, and HDL particle concentrations increased during gestation, with the exception of medium-sized LDL and HDL particles which decreased. Subfraction concentrations were not associated with infant birth weights, though relationships were found between some lipoprotein subfraction concentrations in women with normal versus low birth weight infants (< 2500 kg). HDL's proteome also changed during gestation, showing enrichment in proteins associated with metal ion binding, hemostasis, lipid metabolism, protease inhibitors, proteolysis, and complement activation. Compared to women in the U.S., Gambian women had lower large- and small-sized LDL and HDL concentrations, but similar medium-sized LDL and HDL concentrations., Conclusions: Most lipoprotein subfraction concentrations increase throughout pregnancy in Gambian women and are lower in Gambian vs U.S. women, the exception being medium-sized LDL and HDL particle concentrations which decrease during gestation and are similar in both cohorts of women. The proteomes of HDL also change in ways to support gestation. These changes warrant further study to determine how a lack of change or different changes could impact negative pregnancy outcomes., (© 2023. The Author(s).)

The joint consensus panel of the European Atherosclerosis Society (EAS) and the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) recently addressed present and future challenges in the laboratory diagnostics of atherogenic lipoproteins. Total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, and calculated non-HDL cholesterol (=total - HDL cholesterol) constitute the primary lipid panel for estimating risk of atherosclerotic cardiovascular disease (ASCVD) and can be measured in the nonfasting state. LDL cholesterol is the primary target of lipid-lowering therapies. For on-treatment follow-up, LDL cholesterol shall be measured or calculated by the same method to attenuate errors in treatment decisions due to marked between-method variations. Lipoprotein(a)-cholesterol is part of measured or calculated LDL cholesterol and should be estimated at least once in all patients at risk of ASCVD, especially in those whose LDL cholesterol decline poorly upon statin treatment. Residual risk of ASCVD even under optimal LDL-lowering treatment should be also assessed by non-HDL cholesterol or apolipoprotein B, especially in patients with mild-to-moderate hypertriglyceridemia (2-10 mmol/L). Non-HDL cholesterol includes the assessment of remnant lipoprotein cholesterol and shall be reported in all standard lipid panels. Additional apolipoprotein B measurement can detect elevated LDL particle numbers often unidentified on the basis of LDL cholesterol alone. Reference intervals of lipids, lipoproteins, and apolipoproteins are reported for European men and women aged 20-100 years. However, laboratories shall flag abnormal lipid values with reference to therapeutic decision thresholds., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Rationale: In black women, triglycerides are paradoxically normal in the presence of insulin resistance. This relationship may be explained by race-related differences in central adiposity and SCD (stearoyl-CoA desaturase)-1 enzyme activity index., Objective: In a cross-sectional study, to compare fasting and postprandial triglyceride-rich lipoprotein particle (TRLP) concentrations and size in black compared with white pre- and postmenopausal women and determine the relationship between TRLP subfractions and whole-body insulin sensitivity, hepatic and visceral fat, and SCD-1 levels., Methods and Results: In 122 federally employed women without diabetes mellitus, 73 black (58 African American and 15 African immigrant) and 49 white; age, 44±10 (mean±SD) years; body mass index, 30.0±5.6 kg/m 2 , we measured lipoprotein subfractions using nuclear magnetic resonance. Hepatic fat was measured by proton magnetic resonance spectroscopy, insulin sensitivity index calculated by minimal modeling from a frequently sampled intravenous glucose test, and red blood cell fatty acid profiles were measured by gas chromatography and were used to estimate SCD-1 indices. Hepatic fat, insulin sensitivity index, and SCD-1 were similar in black women and lower than in whites, regardless of menopausal status. Fasting and postprandial large, medium, and small TRLPs, but not very small TRLPs, were lower in black women. Fasting large, medium, and very small TRLPs negatively correlated with insulin sensitivity index and positively correlated with visceral and hepatic fat and SCD-1 activity in both groups. In multivariate models, visceral fat and SCD-1 were associated with total fasting TRLP concentrations (adjR2, 0.39; P =0.001). Black women had smaller postprandial changes in large ( P =0.005) and medium TRLPs ( P =0.007)., Conclusions: Lower visceral fat and SCD-1 activity may contribute to the paradoxical association of lower fasting and postprandial TRLP subfractions despite insulin resistance in black compared with white pre- and postmenopausal women. Similar concentrations of very small TRLPs are related to insulin resistance and could be important mediators of cardiometabolic disease risk in women., Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01809288.

Background: Colchicine has received renewed interest for its potential beneficial effects in secondary prevention of cardiovascular disease. This was presumed to be primarily because of its anti-inflammatory effects; however, limited data exist regarding colchicine's impact on other cardiovascular risk factors., Objective: The aim of this study was to examine if colchicine's anti-inflammatory actions would lead to reduced circulating concentrations of oxidized low-density lipoprotein (oxLDL) in metabolically unhealthy individuals. We also examined if colchicine would improve concentrations of other atherogenic lipoprotein subfractions., Methods: This is a secondary analysis of a double-blind, randomized, placebo-controlled pilot study in which 40 adults with metabolic syndrome were randomized to colchicine 0.6 mg or placebo twice daily for 3 months. Blood samples were collected in the fasted state. OxLDL was measured using enzyme-linked immunosorbent assay. Nuclear magnetic resonance spectroscopy was used to measure other lipoprotein particle subfraction concentrations., Results: Compared with placebo, colchicine reduced markers of inflammation, including C-reactive protein, erythrocyte sedimentation rate, and GlycA (P < .01). Concentrations of oxLDL (P = .019) and small LDL (P = .022) appeared significantly increased in the colchicine arm. Colchicine had no significant effect on other lipoprotein subfractions or lipoprotein particle sizes (all P > .05)., Conclusion: Although colchicine may have benefit in secondary prevention of cardiovascular disease in at-risk individuals, we found no evidence that these effects are because of improvements in circulating atherogenic lipoprotein particle concentrations. Further studies are needed to confirm whether colchicine increases circulating oxLDL and small LDL levels in adults with metabolic syndrome. If true, additional research is warranted to elucidate the mechanisms underlying these associations., (Published by Elsevier Inc.)

Background: Cardiovascular (CV) complications are the most significant cause of mortality in adults with Cushing disease (CD); little is known about CV risk factors in children with CD. Measurement of lipoprotein particles by nuclear magnetic resonance (NMR) spectroscopy is a novel technology to assess CV risk. The objective of the current study is to analyze the NMR lipid profile in pediatric CD patients before and 1 year after remission., Methods: NMR lipid profile was obtained via the Vantera NMR analyzer, using frozen serum samples from 33 CD patients (mean age 13.8 ± 4.0 years) evaluated between 1997 and 2017 at the National Institutes of Health (NIH) Clinical Center (CC)., Results: GlycA (glycosylated acute-phase proteins), triglyceride-rich particles (TRLP medium and very small sizes), low-density lipoprotein (LDL) particles (LDLP total and large size), high-density lipoprotein (HDL) particles (HDLP total, medium and small sizes), total cholesterol, LDL-cholesterol, HDL-cholesterol, GlycA inflammatory biomarker, and apolipoprotein B and apolipoprotein A1 (ApoA1) concentrations showed statistically significant changes after remission of CD (p < 0.05)., Conclusion: In our study population, most of the lipid variables improved post-CD remission, with the exception of HDL and ApoA1, indicating that NMR lipoprotein profile may be a helpful tool in assessing the CV risk in pediatric patients with CD.

We previously demonstrated that the combination of phytosterols (PS) and curcumin administered as dietary supplements significantly lowers LDL-cholesterol (LDL-C) more than either treatment alone. The aim of this study was to investigate the effects of this combination in a novel food (bread) on plasma lipid profiles in hypercholesterolaemic individuals. In a double-blinded, placebo-controlled, 2 × 2 factorial trial, participants were randomised to receive bread fortified with placebo (PL), 2.3 g PS (PS), 228 mg curcumin (CC) or a combination of 2.3 g PS and 228 mg CC (PS-CC) daily for four weeks. Primary outcomes were fasting plasma lipids [total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG)] and secondary outcomes were plasma LDL-particle (LDL-P) profile: LDL-P number and LDL-P size. Cardiovascular disease (CVD) risk (Framingham Risk Algorithm) was also explored. There was no significant difference between PL and CC or PS and PS-CC on blood lipids or CVD risk; therefore, groups were pooled for final analysis: the PL and CC group (PL-C, n = 36) and the PS and PS-CC group (PS-C, n = 39). PS-C significantly lowered TC (-0.52 mmol L-1, p < 0.0001), LDL-C (-0.49 mmol L-1, p < 0.0001) and CVD risk (-1.1 absolute %, p = 0.0005) compared to the PL-C group. Reductions from baseline in the PS-C group compared to that in the PL-C group were 7.6% and 10.6% for TC and LDL-C, respectively, and statistically significant (p < 0.0001). CVD-risk in the PS-C group reduced significantly (-12.7%) compared to that in the PL-C group (p = 0.0005). HDL-C and TG remained unchanged. The LDL-P number significantly decreased in the PS-C group by 124.33 nmol L-1 compared to that in the PL-C group (p = 0.005) and both groups showed a significant decrease in LDL-P size (p < 0.01); however, the absolute nm change in LDL-P size did not differ between groups and the percent change in LDL-P size in the PS-C group was borderline significant (-0.89%, p = 0.05) compared to that in the PL-C group. Regular consumption of PS-enriched bread with or without curcumin lowers blood cholesterol; however, curcumin alone did not influence blood lipids. Bread may be a convenient means of delivering PS with greater compliance for reducing the blood cholesterol concentration.

Familial LCAT deficiency (FLD) patients accumulate lipoprotein-X (LP-X), an abnormal nephrotoxic lipoprotein enriched in free cholesterol (FC). The low neutral lipid content of LP-X limits the ability to detect it after separation by lipoprotein electrophoresis and staining with Sudan Black or other neutral lipid stains. A sensitive and accurate method for quantitating LP-X would be useful to examine the relationship between plasma LP-X and renal disease progression in FLD patients and could also serve as a biomarker for monitoring recombinant human LCAT (rhLCAT) therapy. Plasma lipoproteins were separated by agarose gel electrophoresis and cathodal migrating bands corresponding to LP-X were quantified after staining with filipin, which fluoresces with FC, but not with neutral lipids. rhLCAT was incubated with FLD plasma and lipoproteins and LP-X changes were analyzed by agarose gel electrophoresis. Filipin detects synthetic LP-X quantitatively (linearity 20-200 mg/dl FC; coefficient of variation <20%) and sensitively (lower limit of quantitation <1 mg/ml FC), enabling LP-X detection in FLD, cholestatic, and even fish-eye disease patients. rhLCAT incubation with FLD plasma ex vivo reduced LP-X dose dependently, generated HDL, and decreased lipoprotein FC content. Filipin staining after agarose gel electrophoresis sensitively detects LP-X in human plasma and accurately quantifies LP-X reduction after rhLCAT incubation ex vivo.

Rationale: Psoriasis is a systemic inflammatory skin disease associated with cardiovascular disease and lipid dysfunction. However, traditional lipid parameters have limited prognostic value, whereas assessing oxidation-modified lipids in this inflammatory driven condition may capture additional risk. Recently, a study showed that psoriasis was associated with increased lipid-rich coronary plaques; therefore, investigating potential relationships with oxidation-modified lipids may speed understanding of increased cardiovascular disease in psoriasis., Objective: To understand whether oxidation-modified lipids associate with traditional lipid phenotypes, cardiometabolic disease biomarkers, and total coronary plaque, with focus on noncalcified burden (NCB) by coronary computed tomographic angiography in psoriasis., Methods and Results: Psoriasis subjects and controls (n=252) had profiling for oxidation-modified LDL (low-density lipoprotein), HDL (high-density lipoprotein), Lp(a) (lipoprotein[a]), cholesterol efflux capacity, lipoprotein particle size and number by NMR spectroscopy, and PON-1 (paraoxonase-1) activity. Blinded coronary computed tomographic angiography coronary artery disease characterization included total burden, NCB, and dense-calcified burden. Compared with healthy volunteers, psoriasis subjects were older (mean age, 50.1), had increased body mass index, and homeostatic model assessment of insulin resistance. Psoriasis subjects had increase in oxidized Lp(a), Lp(a), and oxidized HDL (oxHDL; P <0.05 for all) with significant association of oxidized LDL (β=0.10; P=0.020) and oxHDL (β=-0.11; P=0.007) with NCB. Moreover, psoriasis subjects expressed significantly higher PON-1 (kU/µL) activity compared with healthy volunteers (8.55±3.21 versus 6.24±3.82; P=0.01). Finally, psoriasis treatment was associated with a reduction in oxHDL (U/mL; 203.79±88.40 versus 116.36±85.03; P<0.001) and with a concomitant decrease in NCB at 1 year (1.04±0.44 versus 0.95±0.32; P=0.03)., Conclusions: Traditional lipids did not capture risk of lipid-rich plaque as assessed by NCB, whereas assaying oxidation-modification of lipids revealed significant association with oxidized LDL and oxHDL. The PON-1 activity was increased in psoriasis suggesting possible compensatory antioxidative effect. Psoriasis treatment was associated with a reduction in oxHDL. These findings support performance of larger studies to understand oxidation-modified lipids in inflammatory states.

Purpose of Review: Summarize the initial discovery of discoidal high-density lipoprotein (HDL) in human plasma and review more recent innovations that span the use of reconstituted nanodisc HDL for membrane protein characterization to its use as a drug carrier and a novel therapeutic agent for cardiovascular disease., Recent Findings: Using a wide variety of biophysical techniques, the structure and composition of endogenous discoidal HDL have now largely been solved. This has led to the development of new methods for the in vitro reconstitution of nanodisc HDL, which have proven to have a wide variety of biomedical applications. Nanodisc HDL has been used as a platform for mimicking the plasma membrane for the reconstitution and investigation of the structures of several plasma membrane proteins, such as cytochrome P450s and ABC transporters. Nanodisc HDL has also been designed as drug carriers to transport amphipathic, as well as hydrophobic small molecules, and has potential therapeutic applications for several diseases. Finally, nanodisc HDL itself like native discoidal HDL can mediate cholesterol efflux from cells and are currently being tested in late-stage clinical trials for cardiovascular disease. The discovery of the characterization of native discoidal HDL has inspired a new field of synthetic nanodisc HDL, which has offered a growing number of unanticipated biomedical applications.

Background and Aims: Concentrated fish oils, containing a mixture of long-chain monounsaturated fatty acids (LCMUFA) with aliphatic chains longer than 18 C atoms (i.e., C20:1 and C22:1), have been shown to attenuate atherosclerosis development in mouse models. It is not clear, however, how individual LCMUFA isomers may act on atherosclerosis., Methods: In the present study, we used saury fish oil-derived concentrates enriched in either C20:1 or C22:1 isomer fractions to investigate their individual effect on atherosclerosis and lipoprotein metabolism. LDLR-deficient (LDLr -/- ) mice were fed a Western diet supplemented with 5% (w/w) of either C20:1 or C22:1 concentrate for 12 wk., Results: Compared to the control Western diet with no supplement, both LCMUFA isomers increased hepatic levels of LCMUFA by 2∼3-fold (p < 0.05), and decreased atherosclerotic lesion areas by more than 40% (p < 0.05), although there were no major differences in plasma lipoproteins or hepatic lipid content. Both LCMUFA isomers significantly decreased plasma CRP levels, improved Abca1-dependent cholesterol efflux capacity of apoB-depleted plasma, and enhanced Ppar transcriptional activities in HepG2 cells. LC-MS/MS proteomic analysis of lipoproteins (HDL, LDL and VLDL) revealed that both LCMUFA isomer diets resulted in similar potentially beneficial alterations in proteins involved in complement activation, blood coagulation, and lipid metabolism. Several lipoprotein proteome changes were significantly correlated with atherosclerotic plaque reduction., Conclusions: Dietary supplementation with the LCMUFA isomers C20:1 or C22:1 was equally effective in reducing atherosclerosis in LDLr -/- mice and this may partly occur through activation of the Ppar signaling pathways and favorable alterations in the proteome of lipoproteins., (Published by Elsevier B.V.)

Lipoproteins, such as high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very-low density lipoprotein (VLDL), play a critical role in heart disease. Lipoproteins vary in size and shape as well as in their apolipoprotein content. Here, we developed a new experimental framework to study freely diffusing lipoproteins from human blood, allowing analysis of even the smallest HDL with a radius of 5 nm. In an easily constructed confinement chamber, individual HDL, LDL, and VLDL particles labeled with three distinct fluorophores were simultaneously tracked by wide-field fluorescence microscopy and their sizes were determined by their motion. This technique enables studies of individual lipoproteins in solution and allows characterization of the heterogeneous properties of lipoproteins which affect their biological function but are difficult to discern in bulk studies.

Objective: The American College of Cardiology and American Heart Association have issued guidelines indicating that the contribution of apolipoprotein B-100 (ApoB) to cardiovascular risk assessment remains uncertain. The present analysis evaluates whether lipoprotein particle measures convey risk of coronary heart disease (CHD) in 4679 Multi-Ethnic Study of Atherosclerosis (MESA) participants., Approach and Results: Cox regression analysis was performed to determine associations between lipids or lipoproteins and primary CHD events. After adjustment for nonlipid variables, lipoprotein particle levels in fourth quartiles were found to convey significantly greater risk of incident CHD when compared to first quartile levels (hazard ratio [HR]; 95% confidence interval [CI]): ApoB (HR, 1.84; 95% CI, 1.25-2.69), ApoB/ApoA-I (HR, 1.91; 95% CI, 1.32-2.76), total low-density lipoprotein-particles (LDL-P; HR, 1.77; 95% CI, 1.21-2.58), and the LDL-P/HDL-P (high-density lipoprotein-P) ratio (HR, 2.28; 95% CI, 1.54-3.37). Associations between lipoprotein particle measures and CHD were attenuated after adjustment for standard lipid panel variables. Using the American Heart Association/American College of Cardiology risk calculator as a baseline model for CHD risk assessment, significant net reclassification improvement scores were found for ApoB/ApoA-I (0.18; P=0.007) and LDL-P/high-density lipoprotein-P (0.15; P<0.001). C-statistics revealed no significant increase in CHD event discrimination for any lipoprotein measure., Conclusions: Lipoprotein particle measures ApoB/ApoA-I and LDL-P/high-density lipoprotein-P marginally improved net reclassification improvement scores, but null findings for corresponding c-statistic are not supportive of lipoprotein testing. The attenuated associations of lipoprotein particle measures with CHD after the adjustment for lipids indicate that their measurement does not detect risk that is unaccounted for by the standard lipid panel. However, the possibility that lipoprotein measures may identify CHD risk in a subpopulation of individuals with normal cholesterol, but elevated lipoprotein particle numbers cannot be ruled out., (© 2014 American Heart Association, Inc.)

Mice with genetic deletion of the cholesterol transporter ATP binding cassette G1 (ABCG1) have pulmonary lipidosis and enhanced innate immune responses in the airway. Whether ABCG1 regulates adaptive immune responses to the environment is unknown. To this end, Abcg1(+/+) and Abcg1(-/-) mice were sensitized to OVA via the airway using low-dose LPS as an adjuvant, and then challenged with OVA aerosol. Naive Abcg1(-/-) mice displayed increased B cells, CD4(+) T cells, CD8(+) T cells, and dendritic cells (DCs) in lung and lung-draining mediastinal lymph nodes, with lung CD11b(+) DCs displaying increased CD80 and CD86. Upon allergen sensitization and challenge, the Abcg1(-/-) airway, compared with Abcg1(+/+), displayed reduced Th2 responses (IL-4, IL-5, eosinophils), increased neutrophils and IL-17, but equivalent airway hyperresponsiveness. Reduced Th2 responses were also found using standard i.p. OVA sensitization with aluminum hydroxide adjuvant. Mediastinal lymph nodes from airway-sensitized Abcg1(-/-) mice produced reduced IL-5 upon ex vivo OVA challenge. Abcg1(-/-) CD4(+) T cells displayed normal ex vivo differentiation, whereas Abcg1(-/-) DCs were found paradoxically to promote Th2 polarization. Th17 cells, IL-17(+) γδT cells, and IL-17(+) neutrophils were all increased in Abcg1(-/-) lungs, suggesting Th17 and non-Th17 sources of IL-17 excess. Neutralization of IL-17 prior to challenge normalized eosinophils and reduced neutrophilia in the Abcg1(-/-) airway. We conclude that Abcg1(-/-) mice display IL-17-mediated suppression of eosinophilia and enhancement of neutrophilia in the airway following allergen sensitization and challenge. These findings identify ABCG1 as a novel integrator of cholesterol homeostasis and adaptive immune programs.

Lecithin cholesterol acyl transferase (LCAT) deficiency is associated with low high-density lipoprotein (HDL) and the presence of an abnormal lipoprotein called lipoprotein X (Lp-X) that contributes to end-stage renal disease. We examined the possibility of using LCAT an as enzyme replacement therapy agent by testing the infusion of human recombinant (r)LCAT into several mouse models of LCAT deficiency. Infusion of plasma from human LCAT transgenic mice into LCAT-knockout (KO) mice rapidly increased HDL-cholesterol (C) and lowered cholesterol in fractions containing very-low-density lipoprotein (VLDL) and Lp-X. rLCAT was produced in a stably transfected human embryonic kidney 293f cell line and purified to homogeneity, with a specific activity of 1850 nmol/mg/h. Infusion of rLCAT intravenously, subcutaneously, or intramuscularly into human apoA-I transgenic mice showed a nearly identical effect in increasing HDL-C approximately 2-fold. When rLCAT was intravenously injected into LCAT-KO mice, it showed a similar effect as plasma from human LCAT transgenic mice in correcting the abnormal lipoprotein profile, but it had a considerably shorter half-life of approximately 1.23 ± 0.63 versus 8.29 ± 1.82 h for the plasma infusion. rLCAT intravenously injected in LCAT-KO mice crossed with human apolipoprotein (apo)A-I transgenic mice had a half-life of 7.39 ± 2.1 h and increased HDL-C more than 8-fold. rLCAT treatment of LCAT-KO mice was found to increase cholesterol efflux to HDL isolated from mice when added to cells transfected with either ATP-binding cassette (ABC) transporter A1 or ABCG1. In summary, rLCAT treatment rapidly restored the normal lipoprotein phenotype in LCAT-KO mice and increased cholesterol efflux, suggesting the possibility of using rLCAT as an enzyme replacement therapy agent for LCAT deficiency.

Rationale: Mice with genetic deletion of the cholesterol efflux transporter, ATP-binding cassette (ABC) G1, have pulmonary lipidosis and chronic pulmonary inflammation. Whether ABCG1 regulates host defense is unknown., Objectives: To determine whether ABCG1 regulates pulmonary innate immunity and host defense, and to investigate the underlying molecular/cellular mechanisms., Methods: Abcg1(+/+) and Abcg1(-/-) mice were challenged with intrapulmonary lipopolysaccharide (LPS) or Klebsiella pneumoniae, intravenous K. pneumoniae, or intraperitoneal LPS. Phenotypic responses were profiled. Bone marrow chimeras and in vitro assays were used to differentiate and characterize the role of hematopoietic versus nonhematopoietic ABCG1 in host defense., Measurements and Main Results: Unexposed Abcg1(-/-) mice had normal numbers of circulating neutrophils, but increased neutrophil recruitment to the airspace and lung parenchyma, and increased airspace cytokines and chemokines in the steady state. After intrapulmonary LPS or K. pneumoniae, Abcg1(-/-) mice displayed exaggerated further neutrophil recruitment to and degranulation in the airspace, and elevated airspace cytokine/chemokine induction. Alveolar macrophage ABCG1 was critical, as ABCG1 deficiency in hematopoietic cells was sufficient to enhance responses in vivo, and Abcg1(-/-) alveolar macrophages adopted a "foam cell" phenotype, and were hyperresponsive ex vivo. Pulmonary compartmentalization and clearance of K. pneumoniae were increased in Abcg1(-/-) mice, indicating enhanced host defense. By contrast, Abcg1(+/+) and Abcg1(-/-) mice had equivalent responses to intravenous K. pneumoniae and intraperitoneal LPS, suggesting that ABCG1 regulates innate immunity in a tissue-selective manner., Conclusions: Abcg1(-/-) mice have an enhanced pulmonary host defense response driven predominantly by hematopoietic cells.

Purpose of Review: MicroRNAs (miRNA) are mediators of post-transcriptional gene expression that likely regulate most biological pathways and networks. The study of miRNAs is a rapidly emerging field; recent findings have revealed a significant role for miRNAs in atherosclerosis and lipoprotein metabolism, which will be described in this review., Recent Findings: The discovery of miRNA gene regulatory mechanisms contributing to endothelial integrity, macrophage inflammatory response to atherogenic lipids, vascular smooth muscle-cell proliferation, and cholesterol synthesis are described. Furthermore, recent evidence suggests that miRNAs may play a role in mediating the beneficial pleiotropic effects observed with statin-based lipid-lowering therapies. New modifications to miRNA mimetics and inhibitors, increasing targeting efficacy and cellular uptake, will likely enable future therapies to exploit miRNA gene regulatory networks., Summary: At this time, the applicability and full potential of miRNAs in clinical practice is unknown. Nonetheless, recent advances in miRNA delivery and inhibition hold great promise of a tremendous clinical impact in atherosclerosis and cholesterol regulation.

We previously reported that liver-specific overexpression of ABCG5/G8 in mice is not atheroprotective, suggesting that increased biliary cholesterol secretion must be coupled with decreased intestinal cholesterol absorption to increase net sterol loss from the body and reduce atherosclerosis. To evaluate this hypothesis, we fed low density lipoprotein receptor-knockout (LDLr-KO) control and ABCG5/G8-transgenic (ABCG5/G8-Tg)xLDLr-KO mice, which overexpress ABCG5/G8 only in liver, a Western diet containing ezetimibe to reduce intestinal cholesterol absorption. On this dietary regimen, liver-specific ABCG5/G8 overexpression increased hepatobiliary cholesterol concentration and secretion rates (1.5-fold and 1.9-fold, respectively), resulting in 1.6-fold increased fecal cholesterol excretion, decreased hepatic cholesterol, and increased (4.4-fold) de novo hepatic cholesterol synthesis versus LDLr-KO mice. Plasma lipids decreased (total cholesterol, 32%; cholesteryl ester, 32%; free cholesterol, 30%), mostly as a result of reduced non-high density lipoprotein-cholesterol and apolipoprotein B (apoB; 36% and 25%, respectively). ApoB-containing lipoproteins were smaller and lipid-depleted in ABCG5/G8-TgxLDLr-KO mice. Kinetic studies revealed similar 125I-apoB intermediate density lipoprotein/LDL fractional catabolic rates, but apoB production rates were decreased 37% in ABCG5/G8-TgxLDLr-KO mice. Proximal aortic atherosclerosis decreased by 52% (male) and 59% (female) in ABCG5/G8-TgxLDLr-KO versus LDLr-KO mice fed the Western/ezetimibe diet. Thus, increased biliary secretion, resulting from hepatic ABCG5/G8 overexpression, reduces atherogenic risk in LDLr-KO mice fed a Western diet containing ezetimibe. These findings identify distinct roles for liver and intestinal ABCG5/G8 in modulating sterol metabolism and atherosclerosis.

ABCG1 promotes cholesterol efflux from cells, but ABCG1(-/-) bone marrow transplant into ApoE(-/-) and LDLr(-/-) mice reduces atherosclerosis. To further investigate the role of ABCG1 in atherosclerosis, ABCG1 transgenic mice were crossed with LDLr-KO mice and placed on a high-fat western diet. Increased expression of ABCG1 mRNA was detected in liver (1.8-fold) and macrophages (2.7-fold), and cholesterol efflux from macrophages to HDL was also increased (1.4-fold) in ABCG1xLDLr-KO vs. LDLr-KO mice. No major differences were observed in total plasma lipids. However, cholesterol in the IDL-LDL size range was increased by approximately 50% in ABCG1xLDLr-KO mice compared to LDLr-KO mice. Atherosclerosis increased by 39% (10.1+/-0.8 vs 6.1+/-0.9% lesion area, p=0.02), as measured by en face analysis, and by 53% (221+/-98 vs 104+/-58x10(3)microm(2), p =0.01), as measured by cross-sectional analysis in ABCG1xLDLr-KO mice. Plasma levels for MCP-1 (1.5-fold) and TNF-alpha (1.2-fold) were also increased in ABCG1xLDLr-KO mice. In summary, these findings suggest that enhanced expression of ABCG1 increases atherosclerosis in LDLr-KO mice, despite its role in promoting cholesterol efflux from cells.

Mutations in the ATP-binding cassette (ABC) proteins ABCG5 or ABCG8 cause sitosterolemia, a condition with increased accumulation of plant sterols. Upon high level expression of the ABCG5 and ABCG8 proteins in baculovirus-Sf9 cell expression system we found a distinct, vanadate sensitive ATPase activity in isolated membrane preparations only when the two proteins were co-expressed. This ATPase activity was significantly stimulated by the addition of certain androgen hormones and analogs, and was effectively inhibited by progesterone. Our results provide a new aspect of biochemical and functional characterization of the ABCG5/ABCG8 proteins and their possible involvement in steroid hormone transport or regulation.

The identification of ABCA1 as a key transporter responsible for cellular lipid efflux has led to considerable interest in defining its role in cholesterol metabolism and atherosclerosis. In this study, the effect of overexpressing ABCA1 in the liver of LDLr-KO mice was investigated. Compared with LDLr-KO mice, ABCA1-Tg x LDLr-KO (ABCA1-Tg) mice had significantly increased plasma cholesterol levels, mostly because of a 2.8-fold increase in cholesterol associated with a large pool of apoB-lipoproteins. ApoB synthesis was unchanged but the catabolism of (125)I-apoB-VLDL and -LDL were significantly delayed, accounting for the 1.35-fold increase in plasma apoB levels in ABCA1-Tg mice. We also found rapid in vivo transfer of free cholesterol from HDL to apoB-lipoproteins in ABCA1-Tg mice, associated with a significant 2.7-fold increase in the LCAT-derived cholesteryl linoleate content found primarily in apoB-lipoproteins. ABCA1-Tg mice had 1.4-fold increased hepatic cholesterol concentrations, leading to a compensatory 71% decrease in de novo hepatic cholesterol synthesis, as well as enhanced biliary cholesterol, and bile acid secretion. CAV-1, CYP2b10, and ABCG1 were significantly induced in ABCA1-overexpressing livers; however, no differences were observed in the hepatic expression of CYP7alpha1, CYP27alpha1, or ABCG5/G8 between ABCA1-Tg and control mice. As expected from the pro-atherogenic plasma lipid profile, aortic atherosclerosis was increased 10-fold in ABCA1-Tg mice. In summary, hepatic overexpression of ABCA1 in LDLr-KO mice leads to: 1) expansion of the pro-atherogenic apoB-lipoprotein cholesterol pool size via enhanced transfer of HDL-cholesterol to apoB-lipoproteins and delayed catabolism of cholesterol-enriched apoB-lipoproteins; 2) increased cholesterol concentration in the liver, resulting in up-regulated hepatobiliary sterol secretion; and 3) significantly enhanced aortic atherosclerotic lesions.

The ATP binding cassette (ABC) half-transporters ABCG5 and ABCG8 facilitate biliary and intestinal removal of neutral sterols. Here, we identify a binding site for the orphan nuclear receptor liver receptor homolog-1 (LRH-1) at nt 134-142 of the ABCG5/ABCG8 intergenic region necessary for the activity of both the ABCG5 and ABCG8 promoters. Mutating this LRH-1 binding site reduced promoter activity of the human ABCG5/ABCG8 intergenic region more than 7-fold in HepG2 and Caco2 cells. Electrophoretic mobility shift assays with HepG2 nuclear extracts demonstrated specific binding of LRH-1 to the LRH-1 binding motif in the human ABCG5/ABCG8 intergenic region. LRH-1 overexpression increased promoter activity up to 1.6-fold and 3-fold in Caco2 and 293 cells, respectively. Finally, deoxycholic acid repressed the ABCG5 and ABCG8 promoters, consistent with bile acid regulation via the farnesoid X receptor-small heterodimeric partner-LRH-1 pathway. These results demonstrate that LRH-1 is a positive transcription factor for ABCG5 and ABCG8 and, in conjunction with studies on LRH-1 activation of other promoters, identify LRH-1 as a "master regulator" for genes involved in sterol and bile acid secretion from liver and intestine.

Background: The accurate measurement of blood lipids and lipoproteins is crucial for the clinical management of atherosclerotic disease risk. Despite progress in standardization, there are still significant variations in preanalytical requirements, methods, nomenclature, and reporting work flows. Content: The guidance document aims to improve standardization of clinical lipid testing work flows. It provides recommendations for the components of the lipid panel, fasting requirements, reporting of results, and specific recommendations for non-high-density lipoprotein cholesterol (non-HDL-C), low-density lipoprotein cholesterol (LDL-C), lipoprotein(a) [Lp(a)], apolipoprotein B (apo B), point-of-care lipid testing, and LDL subfraction testing. Summary: Lipid panels should always report non-HDL-C and LDL-C calculations if possible. Fasting is not routinely required except in specific cases. Modern equations should be utilized for LDL-C calculation. These equations allow for LDL-C reporting at elevated concentrations of triglycerides and obviate the need for direct measured LDL-C in most cases. [ABSTRACT FROM AUTHOR]

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of morbidity and mortality despite effective low-density lipoprotein cholesterol-targeted therapies. This review explores the crucial role of inflammation in the residual risk of ASCVD, emphasizing its impact on atherosclerosis progression and plaque stability. Evidence suggests that high-sensitivity C-reactive protein (hsCRP), and potentially other inflammatory biomarkers, can be used to identify the inflammatory residual ASCVD risk phenotype and may serve as future targets for the development of more efficacious therapeutic approaches. We review the biological basis for the association of inflammation with ASCVD, propose new therapeutic strategies for the use of inflammation-targeted treatments, and discuss current challenges in the implementation of this new treatment paradigm for ASCVD. [ABSTRACT FROM AUTHOR]

Purpose: Metabolic vulnerabilities can exacerbate inflammatory injury and inhibit repair in multiple sclerosis (MS). The purpose was to evaluate whether blood biomarkers of inflammatory and metabolic vulnerability are associated with MS disability and neurodegeneration. Methods: Proton nuclear magnetic resonance spectra were obtained from serum samples from 153 healthy controls, 187 relapsing–remitting, and 91 progressive MS patients. The spectra were analyzed to obtain concentrations of lipoprotein sub-classes, glycated acute-phase proteins, and small-molecule metabolites, including leucine, valine, isoleucine, alanine, and citrate. Composite indices for inflammatory vulnerability, metabolic malnutrition, and metabolic vulnerability were computed. MS disability was measured on the Expanded Disability Status Scale. MRI measures of lesions and whole-brain and tissue-specific volumes were acquired. Results: Valine, leucine, isoleucine, alanine, the Inflammatory Vulnerability Index, the Metabolic Malnutrition Index, and the Metabolic Vulnerability Index differed between healthy control and MS groups in regression analyses adjusted for age, sex, and body mass index. The Expanded Disability Status Scale was associated with small HDL particle levels, inflammatory vulnerability, and metabolic vulnerability. Timed ambulation was associated with inflammatory vulnerability and metabolic vulnerability. Greater metabolic vulnerability and inflammatory vulnerability were associated with lower gray matter, deep gray matter volumes, and greater lateral ventricle volume. Conclusions: Serum-biomarker-derived indices of inflammatory and metabolic vulnerability are associated with disability and neurodegeneration in MS. [ABSTRACT FROM AUTHOR]

Lipoprotein lipase (LPL) mediates hydrolysis of triglycerides (TGs) to supply free fatty acids (FFAs) to tissues. Here, we show that LPL activity is also required for hematopoietic stem progenitor cell (HSPC) maintenance. Knockout of Lpl or its obligatory cofactor Apoc2 results in significantly reduced HSPC expansion during definitive hematopoiesis in zebrafish. A human APOC2 mimetic peptide or the human very low-density lipoprotein, which carries APOC2, rescues the phenotype in apoc2 but not in lpl mutant zebrafish. Creating parabiotic apoc2 and lpl mutant zebrafish rescues the hematopoietic defect in both. Docosahexaenoic acid (DHA) is identified as an important factor in HSPC expansion. FFA-DHA, but not TG-DHA, rescues the HSPC defects in apoc2 and lpl mutant zebrafish. Reduced blood cell counts are also observed in Apoc2 mutant mice at the time of weaning. These results indicate that LPL-mediated release of the essential fatty acid DHA regulates HSPC expansion and definitive hematopoiesis.

Lipoprotein X (LP-X) is an abnormal cholesterol-rich lipoprotein particle that accumulates in patients with cholestatic liver disease and familial lecithin–cholesterol acyltransferase deficiency (FLD). Because there are no high-throughput diagnostic tests for its detection, a proton nuclear magnetic resonance (NMR) spectroscopy-based method was developed for use on a clinical NMR analyzer commonly used for the quantification of lipoproteins and other cardiovascular biomarkers. The LP-X assay was linear from 89 to 1615 mg/dL (cholesterol units) and had a functional sensitivity of 44 mg/dL. The intra-assay coefficient of variation (CV) varied between 1.8 and 11.8%, depending on the value of LP-X, whereas the inter-assay CV varied between 1.5 and 15.4%. The assay showed no interference with bilirubin levels up to 317 mg/dL and was also unaffected by hemolysis for hemoglobin values up to 216 mg/dL. Samples were stable when stored for up to 6 days at 4 °C but were not stable when frozen. In a large general population cohort (n = 277,000), LP-X was detected in only 50 subjects. The majority of LP-X positive cases had liver disease (64%), and in seven cases, had genetic FLD (14%). In summary, we describe a new NMR-based assay for LP-X, which can be readily implemented for routine clinical laboratory testing. [ABSTRACT FROM AUTHOR]

Context: Statins are the lipid-lowering therapy of choice for the prevention of atherosclerotic cardiovascular disease (ASCVD) but their effectiveness in lowering low-density lipoprotein cholesterol (LDL-C) can substantially differ between individuals. In this mini-review, we describe the different causes for a suboptimal statin response and an algorithm for the diagnosis and clinical management of these patients. Evidence Acquisition: A PubMed search using the terms "statin resistance," "statin sensitivity," "statin pharmacokinetics," "cardiovascular disease," and "lipid-lowering therapies" was performed. Published papers in the past 10 years that were relevant to the topic were examined to provide content for this mini-review. Evidence Synthesis: Suboptimal lowering of LDL-C by statins is a major problem in the clinical management of patients and limits the value of this therapeutic approach. There are multiple causes of statin hyporesponsiveness with compliance being the most common explanation. Other causes, such as analytical issues with LDL-C measurement and the presence of common lipid disorders (familial hypercholesterolemia, elevated lipoprotein[a] and secondary dyslipidemias) should be excluded before considering primary statin resistance from rare genetic variants in lipoprotein-related or drug-metabolism genes. A wide variety of nonstatin lipid-lowering drugs are now available and can be added to statins to achieve more effective LDL-C lowering. Conclusions: The evaluation of statin hyporesponsiveness is a multistep process that can lead to the optimization of lipid-lowering therapy for the prevention of ASCVD. It may also lead to the identification of distinct types of dyslipidemias that require specific therapies and/or the genetic screening of family members. [ABSTRACT FROM AUTHOR]

Previous interest in high-density lipoproteins (HDLs) focused on their possible protective role in atherosclerotic cardiovascular disease (ASCVD). Evidence from genetic studies and randomized trials, however, questioned that the inverse association of HDL-cholesterol (HDL-C) is causal. This review aims to provide an update on the role of HDL in health and disease, also beyond ASCVD. Through evolution from invertebrates, HDLs are the principal lipoproteins, while apolipoprotein B-containing lipoproteins first developed in vertebrates. HDLs transport cholesterol and other lipids between different cells like a reusable ferry, but serve many other functions including communication with cells and the inactivation of biohazards like bacterial lipopolysaccharides. These functions are exerted by entire HDL particles or distinct proteins or lipids carried by HDL rather than by its cholesterol cargo measured as HDL-C. Neither does HDL-C measurement reflect the efficiency of reverse cholesterol transport. Recent studies indicate that functional measures of HDL, notably cholesterol efflux capacity, numbers of HDL particles, or distinct HDL proteins are better predictors of ASCVD events than HDL-C. Low HDL-C levels are related observationally, but also genetically, to increased risks of infectious diseases, death during sepsis, diabetes mellitus, and chronic kidney disease. Additional, but only observational, data indicate associations of low HDL-C with various autoimmune diseases, and cancers, as well as all-cause mortality. Conversely, extremely high HDL-C levels are associated with an increased risk of age-related macular degeneration (also genetically), infectious disease, and all-cause mortality. HDL encompasses dynamic multimolecular and multifunctional lipoproteins that likely emerged during evolution to serve several physiological roles and prevent or heal pathologies beyond ASCVD. For any clinical exploitation of HDL, the indirect marker HDL-C must be replaced by direct biomarkers reflecting the causal role of HDL in the respective disease. [ABSTRACT FROM AUTHOR]

Context Identification of insulin resistance (IR) in South Asians, who are at a higher risk for type 2 diabetes, is important. Lack of standardization of insulin assays limits the clinical use of insulin-based surrogate indices. The lipoprotein insulin resistance index (LP-IR), a metabolomic marker, reflects the lipoprotein abnormalities observed in IR. The reliability of the LP-IR index in South Asians is unknown. Objective We evaluated the predictive accuracy of LP-IR compared with other IR surrogate indices in South Asians. Methods In a cross-sectional study (n = 55), we used calibration model analysis to assess the ability of the LP-IR score and other simple surrogate indices (Homeostatic Model Assessment of Insulin Resistance, Quantitative insulin sensitivity check index, Adipose insulin resistance index, and Matsuda Index) to predict insulin sensitivity (SI) derived from the reference frequently sampled intravenous glucose tolerance test. LP-IR index was derived from lipoprotein particle concentrations and sizes measured by nuclear magnetic resonance spectroscopy. Predictive accuracy was determined by root mean squared error (RMSE) of prediction and leave-one-out cross-validation type RMSE of prediction (CVPE). The optimal cut-off of the LP-IR index was determined by the area under the receiver operating characteristic curve (AUROC) and the Youden index. Results The simple surrogate indices showed moderate correlations with SI (r = 0.53-0.69, P <.0001). CVPE and RMSE were not different in any of the surrogate indices when compared with LP-IR. The AUROC was 0.77 (95% CI 0.64-0.89). The optimal cut-off for IR in South Asians was LP-IR >48 (sensitivity: 75%, specificity: 70%). Conclusion The LP-IR index is a simple, accurate, and clinically useful test to assess IR in South Asians. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ahj.2005.03.065 Byline: Debra A. Marshall, Marina N. Vernalis, Alan T. Remaley, Elaine M. Walizer, John P. Scally, Allen J. Taylor Abstract: Ultralow-fat diets are known to reduce high-density lipoprotein cholesterol (HDL-C) levels. In the setting of a multicomponent lifestyle intervention program, relationships between exercise variables and HDL-C levels were examined to determine whether exercise moderates this dietary effect on serum lipids and apolipoproteins. Author Affiliation: Walter Reed Army Medical Center Cardiology Service, Washington, DC Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD National Institutes of Health Department of Laboratory Medicine, Bethesda, MD Article History: Received 11 January 2005; Accepted 27 March 2005 Article Note: (footnote) The opinions or assertions expressed herein are the private views of the authors and are not to be construed as reflecting the views of the Department of the Army or the Department of Defense.

Recent advances in human genetics, together with a large body of epidemiologic, preclinical, and clinical trial results, provide strong support for a causal association between triglycerides (TG), TG-rich lipoproteins (TRL), and TRL remnants, and increased risk of myocardial infarction, ischaemic stroke, and aortic valve stenosis. These data also indicate that TRL and their remnants may contribute significantly to residual cardiovascular risk in patients on optimized low-density lipoprotein (LDL)-lowering therapy. This statement critically appraises current understanding of the structure, function, and metabolism of TRL, and their pathophysiological role in atherosclerotic cardiovascular disease (ASCVD). Key points are (i) a working definition of normo- and hypertriglyceridaemic states and their relation to risk of ASCVD, (ii) a conceptual framework for the generation of remnants due to dysregulation of TRL production, lipolysis, and remodelling, as well as clearance of remnant lipoproteins from the circulation, (iii) the pleiotropic proatherogenic actions of TRL and remnants at the arterial wall, (iv) challenges in defining, quantitating, and assessing the atherogenic properties of remnant particles, and (v) exploration of the relative atherogenicity of TRL and remnants compared to LDL. Assessment of these issues provides a foundation for evaluating approaches to effectively reduce levels of TRL and remnants by targeting either production, lipolysis, or hepatic clearance, or a combination of these mechanisms. This consensus statement updates current understanding in an integrated manner, thereby providing a platform for new therapeutic paradigms targeting TRL and their remnants, with the aim of reducing the risk of ASCVD. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is an inflammatory auto-immune disease of the central nervous system (CNS). Serum glucose alterations and impaired glucose tolerance (IGT) are reported in MS patients, and are commonly associated with the development of cardio-metabolic co-morbidities. We previously found that a subgroup of MS patients shows alterations in their lipoprotein profile that are similar to a pre-cardiovascular risk profile. In addition, we showed that a high-intensity exercise training has a positive effect on IGT in MS patients. In this study, we hypothesize that exercise training positively influences the lipoprotein profile of MS patients. To this end, we performed a pilot study and determined the lipoprotein profile before (controls, n = 40; MS patients, n = 41) and after (n = 41 MS only) 12 weeks of medium-intensity continuous training (MIT, n = 21, ~60% of VO2max) or high-intensity interval training (HIT, n = 20, ~100-200% of VO2max) using nuclear magnetic resonance spectroscopy (NMR). Twelve weeks of MIT reduced intermediate-density lipoprotein particle count ((nmol/L); -43.4%; p < 0.01), low-density lipoprotein cholesterol (LDL-c (mg/dL); -7.6%; p < 0.05) and VLDL size ((nm); -6.6%; p < 0.05), whereas HIT did not influence the lipoprotein profile. These results show that MIT partially normalizes lipoprotein alterations in MS patients. Future studies including larger patient and control groups should determine whether MIT can reverse other lipoprotein levels and function and if these alterations are related to MS disease progression and the development of co-morbidities. [ABSTRACT FROM AUTHOR]

The purpose of this study was to compare components of cardiometabolic risk and health behaviors of 20 family caregivers of allogeneic hematopoietic stem cell transplant patients to those of age, gender, and race/ethnicity-matched controls. A prospective, repeated measures design was used to compare cardiometabolic risk and health behaviors in caregivers and controls at three time-points: pre-transplantation, discharge, and six weeks post-discharge. Measures included components of metabolic syndrome, Reynolds Risk Score, NMR serum lipoprotein particle analyses, and the Health-Promoting Lifestyle Profile II (HPLP-II). Mixed-model repeated measure analyses were used. There were no between or within group differences in LDL cholesterol, HDL cholesterol, and triglycerides. There was a significant interaction effect between time and role in large VLDL concentration (VLDL-P) (F (2, 76) = 4.36, p = .016), with the trajectory of large VLDL-P increasing over time in caregivers while remaining stable in controls. Within caregivers, VLDL particle size (VLDL-Z) was significantly larger at time-point three compared to time-points one (p = .015) and two (p = .048), and VLDL-Z was significantly larger in caregivers than in controls at time point three (p = .012). HPLP-II scores were lower in caregivers than controls at all time-points (p < .01). These findings suggest that caregiving may have a bigger impact on triglycerides than on other lipids, and it is through this pathway that caregivers may be at increased cardiometabolic risk. More sensitive measurement methods, such as NMR lipoprotein particle analyses, may be able to detect early changes in cardiometabolic risk. [ABSTRACT FROM AUTHOR]

Background: Controversy exists about the incremental utility of nontraditional lipid biomarkers [e.g., apolipoprotein (apo) B, apo A-I, and non-HDL-C] in improving cardiovascular disease (CVD) risk prediction when added to a conventional model of traditional risk factors (e.g., total cholesterol, LDL cholesterol, HDL cholesterol, sex, age, smoking status, and blood pressure). Here we present a systematic review that was conducted to assess the use of nontraditional lipid biomarkers including apo B, apo A-I, apo B/A-I ratio, and non-HDL-C in improving CVD risk prediction after controlling for the traditional risk factors in populations at risk for cardiovascular events. Content: This systematic review used the Laboratory Medicine Best Practices (LMBP™) A-6 methods. A total of 9 relevant studies published before and including July 2015 comprised the evidence base for this review. Results from this systematic review indicated that after the adjustment for standard nonlipid and lipid CVD risk factors, nontraditional apolipoprotein biomarkers apo B (overall effect = relative risk: 1.31; 95% CI, 1.22-1.40; 4 studies) and apo B/apo A-I ratio (overall effect = relative risk: 1.31; 95% CI, 1.11-1.38; 7 studies) resulted in significant improvement in long-term CVD risk assessment. Summary: Available evidence showed that nontraditional lipid biomarkers apo B and apo B/apo I ratio can improve the risk prediction for cardiovascular events after controlling for the traditional risk factors for the populations at risk. However, because of insufficient evidence, no conclusions could be made for the effectiveness of apo A-I and non-HDL-C lipid markers to predict the CVD events, indicating a need for more research in this field. [ABSTRACT FROM AUTHOR]

New treatments are needed for patients with asthma who are refractory to standard therapies, such as individuals with a phenotype of "type 2-low" inflammation. This important clinical problem could potentially be addressed by the development of apolipoprotein A-I (apoA-I) mimetic peptides. ApoA-I interacts with its cellular receptor, the ATP-binding cassette subfamily A, member 1 (ABCA1), to facilitate cholesterol efflux out of cells to form nascent high-density lipoprotein particles. The ability of the apoA-I/ABCA1 pathway to promote cholesterol efflux from cells that mediate adaptive immunity, such as antigen-presenting cells, can attenuate their function. Data from experimental murine models have shown that the apoA-I/ABCA1 pathway can reduce neutrophilic airway inflammation, primarily by suppressing the production of granulocyte-colony stimulating factor. Furthermore, administration of apoA-I mimetic peptides to experimental murine models of allergic asthma has decreased both neutrophilic and eosinophilic airway inflammation, as well as airway hyperresponsiveness and mucous cell metaplasia. Higher serum levels of apoA-I have also been associated with less severe airflow obstruction in patients with asthma. Collectively, these results suggest that the apoA-I/ABCA1 pathway may have a protective effect in asthma, and support the concept of advancing inhaled apoA-I mimetic peptides to clinical trials that can assess their safety and effectiveness. Thus, we propose that the development of inhaled apoA-I mimetic peptides as a new treatment could represent a clinical advance for patients with severe asthma who are unresponsive to other therapies. [ABSTRACT FROM AUTHOR]

Background: This single center, double-blinded, cross-over, placebo controlled clinical trial investigated the effect of oral α-cyclodextrin (α-CD), a soluble dietary fiber, on blood lipid and lipoprotein levels in healthy human subjects. α-CD, a cyclical polymer containing 6 glucose subunits, is currently sold as an over the counter food supplement and is also a common additive in many foods. α-CD forms a hydrophobic central cavity that binds lipids and has been shown in animal studies and in previous clinical trials to alter plasma lipid levels. Methods: We screened for healthy subjects, males and females, between ages 18 to 75. Out of total 103 subjects interviewed, 75 subjects completed the study. Qualified individuals in each gender group were randomized into two groups in terms of which treatment arm they received first (placebo vs. α-CD, receiving 6 grams P.O. a day, for 12-14 weeks with a 7 day wash out between arms). The primary outcome variable, plasma total cholesterol, as well as other tests related to lipids and lipoprotein and glucose metabolism, were measured at baseline and at the end of each arm of the study. Results: α-CD was well tolerated; no serious adverse events related to α-CD were observed. Approximately 8 % of the subjects on α-CD complained of minor gastrointestinal symptoms versus 3 % on placebo (p = 0.2). Small-LDL particle number decreased 10 % (p < 0.045) for subjects on α-CD versus placebo. Fasting plasma glucose (1.6 %, p < 0.05) and Insulin resistance index (11 %, p < 0.04) were also decreased when on α-CD versus placebo. Conclusion: α-CD treatment appears to be safe and well tolerated in healthy individuals and showed a modest reduction in small LDL particles, and an improvement in glucose related parameters. [ABSTRACT FROM AUTHOR]

Aims To critically evaluate the clinical implications of the use of non-fasting rather than fasting lipid profiles and to provide guidance for the laboratory reporting of abnormal non-fasting or fasting lipid profiles. Methods and results Extensive observational data, in which random non-fasting lipid profiles have been compared with those determined under fasting conditions, indicate that the maximal mean changes at 1-6 h after habitual meals are not clinically significant [+0.3 mmol/L (26 mg/dL) for triglycerides; 20.2 mmol/L (8 mg/dL) for total cholesterol; 20.2 mmol/L (8 mg/dL) for LDL cholesterol; +0.2 mmol/L (8 mg/dL) for calculated remnant cholesterol; 20.2 mmol/L (8 mg/dL) for calculated non-HDL cholesterol]; concentrations of HDL cholesterol, apolipoprotein A1, apolipoprotein B, and lipoprotein(a) are not affected by fasting/non-fasting status. In addition, non-fasting and fasting concentrations vary similarly over time and are comparable in the prediction of cardiovascular disease. To improve patient compliance with lipid testing, we therefore recommend the routine use of non-fasting lipid profiles, while fasting sampling may be considered when non-fasting triglycerides .5 mmol/L (440 mg/dL). For non-fasting samples, laboratory reports should flag abnormal concentrations as triglycerides ≥2 mmol/L (175 mg/dL), total cholesterol ≥5 mmol/L (190 mg/dL), LDL cholesterol ≥3 mmol/L (115 mg/dL), calculated remnant cholesterol ≥0.9 mmol/L (35 mg/dL), calculated non-HDL cholesterol ≥3.9 mmol/L (150 mg/dL), HDL cholesterol ≤1 mmol/L (40 mg/dL), apolipoprotein A1 ≤1.25 g/L (125 mg/dL), apolipoprotein B ≥1.0 g/L (100 mg/dL), and lipoprotein(a) ≥50 mg/dL (80th percentile); for fasting samples, abnormal concentrations correspond to triglycerides ≥1.7 mmol/L (150 mg/dL). Life-threatening concentrations require separate referral when triglycerides .10 mmol/L (880 mg/dL) for the risk of pancreatitis, LDL cholesterol .13 mmol/L (500 mg/dL) for homozygous familial hypercholesterolaemia, LDL cholesterol .5 mmol/L (190 mg/dL) for heterozygous familial hypercholesterolaemia, and lipoprotein(a) .150 mg/dL (99th percentile) for very high cardiovascular risk. Conclusion We recommend that non-fasting blood samples be routinely used for the assessment of plasma lipid profiles. Laboratory reports should flag abnormal values on the basis of desirable concentration cut-points. Non-fasting and fasting measurements should be complementary but not mutually exclusive. [ABSTRACT FROM AUTHOR]

The focus of this Roundtable discussion is the mysterious lipoprotein Lp(a). There is growing evidence that it confers significant risk of vascular disease at high plasma concentrations. The concentration in plasma is highly variable from person to person but relatively stable in any given individual. The issue of defining this as a target of treatment has many facets, which have stymied clinicians in their management of this risk factor. The pertinent questions are many such as: “How does one obtain the most meaningful measure as there are so many components?” “What agents are truly effective in lowering this lipoprotein particle?” “Does direct treatment with reduction affect risk?” “How does low-density lipoprotein–cholesterol relate to the risk?” “If low-density lipoprotein-cholesterol is reduced, is there residual risk related directly to Lp(a)?” and “Are there effective therapies under development?” For this Roundtable, I am fortunate to have three experts that have studied these questions in various settings and have agreed to answer my questions relevant to these clinical issues. These include Dr Moriarty from the University of Kansas, Dr Remaley from the National Institutes of Health, and Dr Tsimikas from the University of California San Diego. [ABSTRACT FROM AUTHOR]

Lecithin:cholesterol acyltransferase (LCAT) synthesizes most of the plasma cholesteryl esters, and plays a major role in HDL metabolism. Mutations in the LCAT gene cause two syndromes, familial LCAT deficiency and fish-eye disease, both characterized by severe alterations in plasma lipoprotein profile. Renal disease is the major cause of morbidity and mortality in familial LCAT deficiency cases, but an established therapy is not currently available. The present therapy of LCAT deficiency is mainly aimed at correcting the dyslipidemia associated with the disease and at delaying evolution of chronic nephropathy. LCAT deficiency represents a candidate disease for enzyme replacement therapy. In vitro and in vivo studies proved the efficacy of recombinant human LCAT in correcting dyslipidemia, and recombinant human LCAT is presently under development. [ABSTRACT FROM AUTHOR]