High-density lipoprotein and transport of cholesterol and triglyceride in blood

Associations of lipids in adolescence and adulthood with self- and other-directed compassion in adulthood

Self- and other-directed compassion have been linked with better mental and physical health but research on factors contributing to their development is scarce. Previous studies indicate a possible causal relationship of lipids with personality and socioemotional functioning. As an extension to earlier research, in the present study we examine whether lipids assessed in adolescence and adulthood are associated with self-compassion and other-directed compassion in adulthood. The study utilizes data on lipids from two follow-ups in the Northern Finland Birth Cohort 1986 at ages 15-16 and 33-35. In the latter follow-up also self-compassion and other-directed compassion were assessed with the self-compassion scale - short form and the subscale for compassion in the dispositional positive emotions scale, respectively. The sample for the cross-sectional associations of lipids in adulthood with the compassion variables in adulthood includes 1,459 participants, whereas the sample for the longitudinal associations of lipids in adolescence and the compassion variables in adulthood consists of 1,509 participants. The associations were examined with hierarchical linear regression (lipids as continuous variables) and univariate general linear model (lipids as categorical variables). The results suggest that in women, high-density lipoprotein (HDL) cholesterol in adolescence is associated with high empathic concern (a component of other-directed compassion) in adulthood. The results show further that, in women, an HDL cholesterol level above 1.2 mmol/L in adulthood is associated with high other-directed compassion and empathic concern in adulthood. The present study provides tentative evidence that biological factors such as lipids might play a role in the development of empathic concern and other-directed compassion.

Stratification of ovarian cancer borderline from high-grade serous carcinoma patients by quantitative serum NMR spectroscopy of metabolites, lipoproteins, and inflammatory markers

Background: Traditional diagnosis is based on histology or clinical-stage classification which provides no information on tumor metabolism and inflammation, which, however, are both hallmarks of cancer and are directly associated with prognosis and severity. This project was an exploratory approach to profile metabolites, lipoproteins, and inflammation parameters (glycoprotein A and glycoprotein B) of borderline ovarian tumor (BOT) and high-grade serous ovarian cancer (HGSOC) for identifying additional useful serum markers and stratifying ovarian cancer patients in the future. Methods: This project included 201 serum samples of which 50 were received from BOT and 151 from high-grade serous ovarian cancer (HGSOC), respectively. All the serum samples were validated and phenotyped by ¹H-NMR-based metabolomics with in vitro diagnostics research (IVDr) standard operating procedures generating quantitative data on 38 metabolites, 112 lipoprotein parameters, and 5 inflammation markers. Uni- and multivariate statistics were applied to identify NMR-based alterations. Moreover, biomarker analysis was carried out with all NMR parameters and CA-125. Results: Ketone bodies, glutamate, 2-hydroxybutyrate, glucose, glycerol, and phenylalanine levels were significantly higher in HGSOC, while the same tumors showed significantly lower levels of alanine and histidine. Furthermore, alanine and histidine and formic acid decreased and increased, respectively, over the clinical stages. Inflammatory markers glycoproteins A and B (GlycA and GlycB) increased significantly over the clinical stages and were higher in HGSOC, alongside significant changes in lipoproteins. Lipoprotein subfractions of VLDLs, IDLs, and LDLs increased significantly in HGSOC and over the clinical stages, while total plasma apolipoprotein A1 and A2 and a subfraction of HDLs decreased significantly over the clinical stages. Additionally, LDL triglycerides significantly increased in advanced ovarian cancer. In biomarker analysis, glycoprotein inflammation biomarkers behaved in the same way as the established clinical biomarker CA-125. Moreover, CA-125/GlycA, CA-125/GlycB, and CA-125/Glycs are potential biomarkers for diagnosis, prognosis, and treatment response of epithelial ovarian cancer (EOC). Last, the quantitative inflammatory parameters clearly displayed unique patterns of metabolites, lipoproteins, and CA-125 in BOT and HGSOC with clinical stages I-IV. Conclusion: ¹H-NMR-based metabolomics with commercial IVDr assays could detect and identify altered metabolites and lipoproteins relevant to EOC development and progression and show that inflammation (based on glycoproteins) increased along with malignancy. As inflammation is a hallmark of cancer, glycoproteins, thereof, are promising future serum biomarkers for the diagnosis, prognosis, and treatment response of EOC. This was supported by the definition and stratification of three different inflammatory serum classes which characterize specific alternations in metabolites, lipoproteins, and CA-125, implicating that future diagnosis could be refined not only by diagnosed histology and/or clinical stages but also by glycoprotein classes.

Lipoproteins as Markers for Monitoring Cancer Progression

Lipoproteins are among the contributors of energy for the survival of cancer cells. Studies indicate there are complex functions and metabolism of lipoproteins in cancer. The current review is aimed at providing updates from studies related to the monitoring of lipoproteins in different types of cancer. This had led to numerous clinical and experimental studies. The review covers the major lipoproteins such as LDL cholesterol (LDL-C), oxidized low-density lipoprotein cholesterol (oxLDL-C), very low-density lipoprotein cholesterol (VLDL-C), and high-density lipoprotein cholesterol (HDL-C). This is mainly due to increasing evidence from clinical and experimental studies that relate association of lipoproteins with cancer. Generally, a significant association exists between LDL-C with carcinogenesis and high oxLDL with metastasis. This warrants further investigations to include Mendelian randomization design and to be conducted in a larger population to confirm the significance of LDL-C and its oxidized form as prognostic markers of cancer.

Second-trimester and third-trimester maternal lipid profiles significantly correlated to LGA and macrosomia

BACKGROUND

According to the theory of fetal-derived adult diseases, abnormal fetal development might affect the occurrence of diseases in adulthood, and appropriate fetal growth status intrauterine might have a beneficial effect on it. To adapt properly for fetal development, there are numerous changes in the maternal physiology during pregnancy, including blood lipid metabolism. The aim of this study is to evaluate the association between lipid profiles in the second and third trimesters of normal pregnancy and fetal birth weight.

MATERIALS AND METHODS

The study population was derived from 5695 pregnant women, who maintained routine prenatal care at the women's hospital of Zhejiang University, School of medicine January 1, 2014, and December 31, 2014. The pregnant women in this study all carried uncomplicated singleton pregnancies to at least 37 weeks.

RESULTS

The mean (standard deviation) birth weight was 3361.00 (385.94) g; 413 (7.3%) of the infants were large for gestational age, and 330 (5.8%) were macrosomia. On multiple linear regression analysis, positive determinants of birth weight were gravidity, parity, gestational age at delivery, male infant, maternal height, and weight before pregnancy, weight gain during pregnancy, fasting blood glucose (FBG) level, second-trimester cholesterol (TC) and third-trimester triglyceride (TG), gestational albumin (ALB), and third-trimester high-density lipoprotein (HDL-C) levels were each negatively associated with birth weight. On logistic regression analysis, the significant metabolic lipid predictors of delivering a large-for-gestational-age infant were second- and third-trimester TG (aOR = 1.178, 95% CI 1.032-1.344, p = 0.015; aOR = 1.106, 95% CI 1.043-1.173, p = 0.001, respectively) and second- and third-trimester HDL-C level (aOR = 0.655, 95% CI 0.491-0.874, p = 0.004; aOR = 0.505, 95% CI 0.391-0.651, p < 0.001, respectively). Third-trimester TG and HDL-C were stable predictors of large-for-gestational-age infants in stratification analysis. High TG and low HDL-C level during third trimester could be considered as indicators of a high risk of large for gestational age (LGA) and macrosomia, regardless of infant gender.

CONCLUSION

These results suggest that future lifestyle programs in women of reproductive age with a focus on lowering TG levels (i.e., diet, weight reduction, and physical activity) may help to reduce the incidence of LGA and macrosomia.

Dynamic changes of lipid profile in severe hypertriglyceridemia-induced acute pancreatitis patients under double filtration plasmapheresis: a retrospective observational study

Background

To investigate the dynamic change of lipid profile under double filtration plasmapheresis (DFPP) in severe hypertriglyceridemia-induced acute pancreatitis (sHTGP) patients and ascertain the association between these changes and the clinical prognosis.

Methods

sHTGP patients admitted within 72 h after disease onset were included, and all the patients received DFPP within 24 h after admission. Lipid profile were detected on admission, consecutive 4 days after DFPP and at discharge.

Results

There were 47 sHTGP patients enrolled in this study. At admission, all the parameters of lipid profile changed significantly except for low density lipoprotein. In the first day after DFPP, the serum level of TG, cholesterol and very low density lipoprotein declined significantly, while the high-density lipoprotein (HDL) as well as apoprotein A1 elevated obviously (P < 0.05). TG maintained the downward trend in the following three days and the other parameters kept steady. Linear regression analysis showed that HDL was negatively correlated with the duration of hospitalization among three adjusted models (P = 0.043, P = 0.029, P = 0.025 respectively).

Conclusion

There was distinct fluctuation of the lipid profile upon the burst of sHTGP and the parameters changed significantly in the first day after DFPP. Among these parameters, HDL may serve as a biomarker for disease prognosis in patients with sHTGP.

Postprandial remodeling of high-density lipoprotein following high saturated fat and high carbohydrate meals

BACKGROUND

Humans spend most of the time in the postprandial state, yet most knowledge about high-density lipoproteins (HDL) derives from the fasted state. HDL protein and lipid cargo mediate HDL's antiatherogenic effects, but whether these HDL constituents change in the postprandial state and are affected by dietary macronutrients remains unknown.

OBJECTIVES

This study aimed to assess changes in HDL protein and lipid composition after the consumption of a high-carbohydrate or high saturated fat (HSF) meal.

METHODS

We isolated HDL from plasma collected during a randomized, cross-over study of metabolically healthy subjects. Subjects consumed isocaloric meals consisting predominantly of either carbohydrate or fat. At baseline and at 3 and 6 hours postprandial, we quantified HDL protein and lipid composition by liquid chromatography-mass spectrometry.

RESULTS

A total of 15 subjects were included (60% female, aged 34 ± 15 years, body mass index: 24.1 ± 2.7 kg/m2). Consumption of the HSF meal led to HDL enrichment in total lipid (P = .006), triglyceride (P = .02), and phospholipid (P = .008) content and a corresponding depletion in protein content. After the HSF meal, 16 of the 25 measured phosphatidylcholine species significantly increased in abundance (P values range from .027 to <.001), along with several sphingolipids including ceramides (P < .004), lactosylceramide (P = .023), and sphingomyelin-14 (P = .013). Enrichment in apolipoprotein A-I (P = .001) was the only significant change in HDL protein composition after the HSF meal. The high-carbohydrate meal conferred only minimal changes in HDL composition.

CONCLUSION

Meal macronutrient content acutely affects HDL composition in the postprandial state, with the HSF meal resulting in enrichment of HDL phospholipid content with possible consequences for HDL function.

Hydrolysable Tannin Supplementation Alters Digestibility and Utilization of Dietary Protein, Lipid, and Carbohydrate in Grass Carp (Ctenopharyngodon idellus)

Tannin, an antinutritional component of plant proteins was fed to grass carp (Ctenopharyngodon idellus, 8. 18 ± 0.81 g) for 8 weeks to investigate their tolerance levels. Semi-purified diets (T0, T1, T2, and T3) with varying levels of hydrolysable tannin (0, 0.75, 1.25, and 1.75% respectively) were used. No significant difference was obtained in weight gain, while feed conversion ratio of T0 was significantly lower than T2. Muscle protein content of T0 and T3 were significantly higher than T2, while lipid content of T0 was significantly higher than other groups. Muscle and hepatic glycogen in T0 were significantly lower than other groups. Muscle saturated fatty acids in T3 were significantly higher than T0, and lowest in T1 and T2, while the poly-unsaturated fatty acids in T1 and T2 were higher than T0 and lowest in T3. Significant increases were obtained in trypsin and amylase activities as tannin levels increased, the lipase activity of T0 and T1 was significantly higher than T2 and T3. Activities of hepatic alanine aminotransferase and aspartate aminotransferase decreased with increasing tannin level. The total protein in serum of T2 was significantly higher than T0 and T1 and lowest in T3, whereas globulin of T2 was significantly higher than T0 and T3 and lowest in T1, while albumin of T1 was significantly higher than other groups. Urea nitrogen of T0 was significantly higher than other groups, triglyceride and total cholesterol significantly increased with tannin level and decreased in T3, significant decreases were obtained in low-density lipoprotein cholesterol and high-density lipoprotein cholesterol in T3. mRNA expression of intestinal TOR was significantly upregulated as dietary tannin increased. In hepatopancreas, the expression of glucokinase in T1 was significantly higher than T2, and lowest in T0 and T3, pyruvate kinase in T2 was significantly higher than T0 and T1 and lowest T3. The expression of lipoprotein lipase upregulated as tannin level and downregulated in T3, and fatty acid synthase downregulated as tannin level. In conclusion, grass carp could tolerate 1.75% dietary tannin without influencing growth. However, 1.25% tannin impaired digestion and metabolism of protein, decreased the deposition of lipid and promoted utilization of carbohydrate.

Impact of Circulating Triglycerides Concentration on Atherosclerotic Disease Status in Middle-Aged Saudi Arabian Dwellers

A number of food micronutrients are reported to influence markers of cardio-metabolic health. There is an expectation that there may be an optimal endocrine profile, with triglycerides as a key factor, which may help minimise atherosclerotic disease and associated risk factors. This study involved 84 participants aged (mean ± SD) 48.2 ± 8.3 years from both sexes segregated into n = 30 controls, n = 25 at-risk, and n = 29 diagnosed with atherosclerosis, including 20 participants using statins. Atherosclerosis status and risk factors were assessed using a combination of clinical records, C-reactive protein (CRP), blood glucose (FBG), lipids profiles, vascular structural and functional characteristics (including carotid-radial pulse wave velocity (CR-PWV), central systolic blood pressure (C-SBP), peripheral systolic blood pressure (P-SBP), peripheral diastolic blood pressure (P-DBP), carotid intima-media thickness (IMT), and carotid artery inter-adventitial diameter (IAD)). There was a significant difference in triglycerides (TG) levels between the clinical groups (p < 0.05) and between the users and non-users of statin (p < 0.001). Significant associations were distinguished between TG and CRP, FBG, high-density lipoprotein (HDL), C-SBP, P-SBP, P-DBP, CR-PWV, heart rate (HR), and body weight in the pooled sample (p < 0.05). In non-users of statin, TG was associated with C-SBP, P-SBP, P-DBP, and HR. In sub-clinical groups, TG was also associated with most of the blood markers. After controlling for statin use, composite z-score analysis revealed 48%, 2%, and 0% differences in in vivo vascular phenotype between high and low TG subgroups in controls, at-risk, and diagnosed atherosclerosis groups, respectively. Thus, TG levels seem to be good indicators for incidence and risk factors of atherosclerosis.

Maternal lipids associated with large-for-gestational-age birth weight in women with type 1 diabetes: results from a prospective single-center study

INTRODUCTION

Despite improvement in diabetes care over the years, the incidence of macrosomia in type 1 diabetic mothers is still very high and even shows an increasing tendency. It is suggested that other factors that maternal hyperglycemia might be associated with excessive fetal growth in diabetic mothers. The aim of this study was to determine whether maternal lipids might contribute to high rates of large-for-gestational-age (LGA) newborns in women with type 1 diabetes (T1DM).

MATERIAL AND METHODS

This prospective, single-center study was performed in a population of women with T1DM admitted to the perinatal center for women with diabetes. Data were collected in the first trimester (< 12^th week), in mid-pregnancy (20^th-24^th weeks), and before delivery (34^th-39^th weeks).

RESULTS

Among 114 women included in the analysis, 30 (26.3%) delivered LGA newborns. The remaining 84 (73.7%) newborns were appropriate for gestational age (AGA). Lower high-density lipoprotein (HDL) HDL concentration in the first trimester was significantly associated with LGA (p = 0.01). Similar associations were observed for the HDL concentrations in mid-pregnancy (p = 0.04) and before delivery (p = 0.03). Higher triglyceride concentrations in the first trimester (p = 0.02) and before delivery (p = 0.008) were associated with LGA. Higher glycated haemoglobin (HbA_1c) levels in mid-pregnancy and before delivery were associated with LGA. The associations between maternal lipids and LGA were independent of maternal body mass index at onset of the study, gestational weight gain and HbA_1c concentrations.

CONCLUSIONS

Decreased HDL and increased triglycerides during pregnancy might contribute to the development of LGA in women with type 1 diabetes.

The biology of circulating microRNAs in cardiovascular disease

BACKGROUND

Since their first description in mammalian cells, more than 2500 microRNA molecules have been predicted or verified within human cells. Recently, extracellular microRNAs have been described, protected from degradation by specialized packaging in extracellular vesicles or RNA-binding proteins.

MATERIALS AND METHODS

We will discuss recent data regarding circulating microRNAs, their potential role as novel biomarkers and intercellular communicators, as well as future challenges of studying and applying such novel biology, particularly in the cardiovascular system.

RESULTS

Circulating microRNAs have been proposed as attractive candidates as both diagnostic and prognostic biomarkers in various diseases, including a spectrum of cardiovascular conditions. Moreover, consistent with our evolving appreciation of the role of exosomes and microvesicles in intercellular communication, it has been proposed that delivery of active microRNAs to recipient tissues may serve as a primary mode of intercellular communication. Indeed, the transfer of functional microRNAs has been demonstrated in in vitro models and has been reported in a few in vivo contexts. In addition, therapeutic application of extracellular microRNAs has also been explored.

CONCLUSION

Over recent years, increasing attention has been paid to the role of circulating miRNAs in cardiovascular disease. As biomarkers and intercellular communicators, circulating miRNAs could play important roles in the prediction, diagnosis and tailored treatment of cardiovascular diseases in the near future.

Extracellular microRNAs in Membrane Vesicles and Non-vesicular Carriers

Great excitement has surrounded the finding that small RNAs are stable in various biofluids and carry specific signatures reflecting physiological and pathological states. In this chapter, we briefly describe the impact of this revolutionary discovery and introduce different subclasses of circulating microRNAs based on their mode of transport. Subsequently, we review the current state-of-the art knowledge on microRNA selection for export, secretion and possible uptake mechanisms and their potential function in circulation. Furthermore, we give an overview on the possible use of cell-free microRNAs as biomarkers and as therapeutic targets. Overall, we aim to highlight open questions and address some of the pitfalls of current extracellular RNA research.

Impact of lipids and lipoproteins on hepatitis C virus infection and virus neutralization

Hepatitis C virus (HCV) infections represent a major global health problem. End-stage liver disease caused by chronic HCV infection is a major indication for liver transplantation. However, after transplantation the engrafted liver inevitably becomes infected by the circulating virus. Direct acting antivirals are not yet approved for use in liver transplant patients, and limited efficacy and severe side effects hamper the use of pegylated interferon combined with ribavirin in a post-transplant setting. Therefore, alternative therapeutic options need to be explored. Viral entry represents an attractive target for such therapeutic intervention. Understanding the mechanisms of viral entry is essential to define the viral and cellular factors involved. The HCV life cycle is dependent of and associated with lipoprotein physiology and the presence of lipoproteins has been correlated with altered antiviral efficacy of entry inhibitors. In this review, we summarise the current knowledge on how lipoprotein physiology influences the HCV life cycle. We focus especially on the influence of lipoproteins on antibodies that target HCV envelope proteins or antibodies that target the cellular receptors of the virus. This information can be particularly relevant for the prevention of HCV re-infection after liver transplantation.

MicroRNAs in Lipid Metabolism and Atherosclerosis

BACKGROUND: 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.CONTENT: Results from recent studies demonstrated a role for miRNAs in endothelial integrity, macrophage inflammatory response to oxidized low-density lipoprotein, vascular smooth muscle cell proliferation and cholesterol synthesis. These mechanisms are all vital to the initiation and proliferation of atherosclerosis and cardiovascular disease. The importance of miRNAs has recently been recognized in cardiovascular sciences and miRNAs will likely become an integral part of our fundamental comprehension of atherosclerosis and lipoprotein metabolism. The extensive impact of miRNA mediated gene regulation and the relative ease of in vivo applicable modifications highlight the enormous potential of miRNA-based therapeutics in cardiovascular diseases.SUMMARY: miRNA studies in the field of lipid metabolism and atherosclerosis are in their infancy, and thus there is tremendous opportunity for discovery in this understudied area. The ability to target miRNAs in vivo through delivery of miRNA-mimics to enhance miRNA function, or antimiRNAs which inhibit miRNAs, has opened new avenues for the development of therapeutics for dyslipidemias and atherosclerosis, offers a unique approach to treating disease by modulating entire biological pathways. These exciting findings support the development of miRNA antagonists as potential therapeutics for the treatment of dyslipidaemia, atherosclerosis and related metabolic diseases.KEYWORDS: atherosclerosis, lipoprotein, HDL, miRNA

Biochemical and functional characterization of charge-defined subfractions of high-density lipoprotein from normal adults

High-density lipoprotein (HDL) is regarded as atheroprotective because it provides antioxidant and anti-inflammatory benefits and plays an important role in reverse cholesterol transport. In this paper, we outline a novel methodology for studying the heterogeneity of HDL. Using anion-exchange chromatography, we separated HDL from 6 healthy individuals into five subfractions (H1 through H5) with increasing charge and evaluated the composition and biologic activities of each subfraction. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis showed that apolipoprotein (apo) AI and apoAII were present in all 5 subfractions; apoCI was present only in H1, and apoCIII and apoE were most abundantly present in H4 and H5. HDL-associated antioxidant enzymes such as lecithin-cholesterol acyltransferase, lipoprotein-associated phospholipase A2, and paraoxonase 1 were most abundant in H4 and H5. Lipoprotein isoforms were analyzed in each subfraction by using matrix-assisted laser desorption-time-of-flight mass spectrometry. To quantify other proteins in the HDL subfractions, we used the isobaric tags for the relative and absolute quantitation approach followed by nanoflow liquid chromatography-tandem mass spectrometry analysis. Most antioxidant proteins detected were found in H4 and H5. The ability of each subfraction to induce cholesterol efflux from macrophages increased with increasing HDL electronegativity, with the exception of H5, which promoted the least efflux activity. In conclusion, anion-exchange chromatography is an attractive method for separating HDL into subfractions with distinct lipoprotein compositions and biologic activities. By comparing the properties of these subfractions, it may be possible to uncover HDL-specific proteins that play a role in disease.

Extracellular communication via microRNA: lipid particles have a new message

The complexity of microRNA (miRNA)-mediated pathway control has burgeoned since the discovery that miRNAs are found in the extracellular space and constitute a form of cell-cell communication. miRNAs have been found in plasma, urine, and saliva and have recently been shown to be carried on lipoproteins. This has led to the proposal that circulating miRNAs may be useful biomarkers of various diseases, including cardiovascular disease, diabetes, and other forms of dysregulated metabolism. Although our understanding of the cellular machinery responsible for the secretion of miRNA is incomplete, it has been demonstrated that miRNAs are packaged into exosomes, microvesicles, and apoptotic bodies by a broad range of cell types. Intriguingly, a large portion of extracellular miRNA is found outside of any lipid-containing vesicle, and instead is associated with RNA binding proteins like argonautes 1 and 2, which may aid in their protection from abundant nucleases in the extracellular space. The excitement for miRNAs as biomarkers is mounting as more and more evidence supports that these noncoding RNAs are actively secreted from diseased tissues, possibly before the onset of overt disease. While caution should be taken in these early days, there is little doubt that extracellular miRNAs will hold tremendous potential as both diagnostic and therapeutic agents.

Sex-specific interaction between APOE genotype and carbohydrate intake affects plasma HDL-C levels: the Strong Heart Family Study

Low plasma levels of high-density lipoprotein cholesterol (HDL-C) are identified as a risk factor for cardiovascular disease (CVD). Sexual dimorphism, however, is widely reported in both HDL-C and CVD, with the underlying explanations of these sexual differences not fully understood. HDL-C is a complex trait influenced by both genes and dietary factors. Here we examine evidence for a sex-specific effect of APOE and the macronutrient carbohydrate on HDL-C, triglycerides (TG) and apoprotein A-1 (ApoA-1) in a sample of 326 male and 423 female participants of the Strong Heart Family Study (SHFS). Using general estimating equations in SAS to account for kinship correlations, stratifying by sex, and adjusting for age, body mass index (BMI) and SHS center, we examine the relationship between APOE genotype and carbohydrate intake on circulating levels of HDL-C, TG, and ApoA-1 through a series of carbohydrate-by-sex interactions and stratified analyses. APOE-by-carbohydrate intake shows significant sex-specific effects. All males had similar decreases in HDL-C levels associated with increased carbohydrate intake. However, only those females with APOE-4 alleles showed significantly lower HDL-C levels as their percent of carbohydrate intake increased, while no association was noted between carbohydrate intake and HDL-C in those females without an APOE-4 allele. These findings demonstrate the importance of understanding sex differences in gene-by-nutrient interaction when examining the complex architecture of HDL-C variation.