Influence of apolipoprotein E genotype on fat-soluble plasma antioxidants in Spanish children

Exploring the relationship between metabolism and immune microenvironment in osteosarcoma based on metabolic pathways

BACKGROUND

Metabolic remodeling and changes in tumor immune microenvironment (TIME) in osteosarcoma are important factors affecting prognosis and treatment. However, the relationship between metabolism and TIME needs to be further explored.

METHODS

RNA-Seq data and clinical information of 84 patients with osteosarcoma from the TARGET database and an independent cohort from the GEO database were included in this study. The activity of seven metabolic super-pathways and immune infiltration levels were inferred in osteosarcoma patients. Metabolism-related genes (MRGs) were identified and different metabolic clusters and MRG-related gene clusters were identified using unsupervised clustering. Then the TIME differences between the different clusters were compared. In addition, an MRGs-based risk model was constructed and the role of a key risk gene, ST3GAL4, in osteosarcoma cells was explored using molecular biological experiments.

RESULTS

This study revealed four key metabolic pathways in osteosarcoma, with vitamin and cofactor metabolism being the most relevant to prognosis and to TIME. Two metabolic pathway-related clusters (C1 and C2) were identified, with some differences in immune activating cell infiltration between the two clusters, and C2 was more likely to respond to two chemotherapeutic agents than C1. Three MRG-related gene clusters (GC1-3) were also identified, with significant differences in prognosis among the three clusters. GC2 and GC3 had higher immune cell infiltration than GC1. GC3 is most likely to respond to immune checkpoint blockade and to three commonly used clinical drugs. A metabolism-related risk model was developed and validated. The risk model has strong prognostic predictive power and the low-risk group has a higher level of immune infiltration than the high-risk group. Knockdown of ST3GAL4 significantly inhibited proliferation, migration, invasion and glycolysis of osteosarcoma cells and inhibited the M2 polarization of macrophages.

CONCLUSION

The metabolism of vitamins and cofactors is an important prognostic regulator of TIME in osteosarcoma, MRG-related gene clusters can well reflect changes in osteosarcoma TIME and predict chemotherapy and immunotherapy response. The metabolism-related risk model may serve as a useful prognostic predictor. ST3GAL4 plays a critical role in the progression, glycolysis, and TIME of osteosarcoma cells.

Vitamin E Derivative with Modified Side Chain Induced Apoptosis by Modulating the Cellular Lipids and Membrane Dynamics in MCF7 Cells

The vitamin E derivative with side chain modification (TC6OAc) has been shown to possess anticancer activity in our earlier in vivo studies. It was hypothesized that, as Vitamin E (VE) and VE derivative are fat soluble lipophilic molecules, they exert their function by modulating the lipid metabolism and related pathways. This study aimed to evaluate the cellular impact of this VE derivative (2,5,7,8-Tetramethyl-2-(4'-Methyl-3'-Pentenyl)-6-Acetoxy Chromane-TC6OH), using α-tocopherol as a reference compound throughout the experiments. Their effects on the cellular metabolism, the biophysical properties of cellular lipids and the functional characteristics of cells were monitored in human estrogen receptor (ER) positive breast cancer cells. It has been documented that TC6OH treatment induces tumor cell apoptosis by dissipating the mitochondrial membrane potential, modulating the lipid, transportation and degradation as well as downregulating certain anti-apoptotic and growth factor related proteins. Due to resistance of ER positive cells to the established therapies, the findings of this study are of translational value.

Relationship of NEFA concentrations to RBP4 and to RBP4/retinol in prepubertal children with and without obesity

BACKGROUND

The regulation of adipose tissue metabolism in early childhood obesity is not well understood. Insulin levels are higher and insulin resistance seems to be present in prepubertal children with obesity but, differing from their behavior in adults with obesity, non-esterified fatty acid (NEFA) concentrations are not increased. Retinol-binding protein (RBP)-4 concentration is associated with obesity and insulin resistance conditions, but the means of this relationship remain unclear, and few studies have taken retinol values into account to evaluate it.

OBJECTIVE

To analyze the relationship between RBP4 concentration and lipolytic products in plasma in 141 prepubertal children aged 6 to 8 years, with and without obesity.

METHODS

Plasma glucose, insulin, triacylglycerols, NEFA, glycerol, leptin, RBP4, and retinol were analyzed in obese and in their normal-weight counterparts. Homeostatic model assessment, quantitative insulin sensitivity check index, and fasting glucose to insulin ratio were calculated as indicators of insulin resistance.

RESULTS

Fasted plasma NEFA concentrations were lower in children with obesity than in their normal weight counterparts, despite leptin, insulin resistance indices, RBP4, retinol, and RBP4/retinol (an index of free-RBP4) being higher. NEFA and glycerol concentrations were inversely correlated with RBP4/retinol in children with obesity but not in those without obesity. In normal weight children, total RBP4 correlated negatively with NEFA and glycerol concentrations and positively with insulin and homeostasis model assessment for insulin resistance. These results indicate that a low saturation of RBP4 with retinol, which implies a higher concentration of free-RBP4, may preserve the antilipolytic function of insulin in adipose tissue in children with obesity.

CONCLUSION

Our findings suggest that, in prepubertal children with obesity and insulin resistance, the amount of RBP4/retinol correlates with the antilipolytic response of the adipose tissue to insulin rather than the total RBP4 concentration.

Plasma Retinol Levels and High-Sensitivity C-Reactive Protein in Prepubertal Children

The relationship between C-reactive protein (CRP) levels and plasma antioxidants has been established in adults. However, the association has been rarely investigated in healthy children. Thus, we examined the cross-sectional association of high-sensitivity CRP (hs-CRP) levels with fat-soluble plasma antioxidant concentrations in a cohort of healthy prepubertal children. We determined hs-CRP levels in 543 healthy six⁻eight-year-old children using a high-sensitivity CRP enzyme-linked immuno sorbent assay (ELISA) kit. The plasma concentrations of lipids, apolipoproteins and lipid-soluble antioxidants (α-tocopherol, γ-tocopherol, lycopene, α-carotene, β-carotene and retinol) were determined using standardized methods. Pearson correlation analysis showed significant correlations between plasma hs-CRP and α-carotene and retinol concentrations. After adjusting by sex, body mass index (BMI) and lipid levels, only the association with retinol remains significant, with children in the highest hs-CRP tertile group (hs-CRP ≥ 0.60 mg/dL) showing significantly lower levels of retinol than those from the tertiles 1 and 2. A stepwise linear regression selected retinol, BMI, apo A-I and sex as predictors of hs-CRP levels, in a model explaining 19.2% of the variability of hs-CRP. In conclusion, in healthy prepubertal children, after adjusting by sex, BMI and lipid levels, hs-CRP concentrations were highly associated with plasma retinol, which is transported in blood bound to retinol-binding protein but were not associated with the lipoprotein-bound antioxidants.

Host-related factors explaining interindividual variability of carotenoid bioavailability and tissue concentrations in humans

Carotenoid dietary intake and their endogenous levels have been associated with a decreased risk of several chronic diseases. There are indications that carotenoid bioavailability depends, in addition to the food matrix, on host factors. These include diseases (e.g. colitis), life-style habits (e.g. smoking), gender and age, as well as genetic variations including single nucleotide polymorphisms that govern carotenoid metabolism. These are expected to explain interindividual differences that contribute to carotenoid uptake, distribution, metabolism and excretion, and therefore possibly also their association with disease risk. For instance, digestion enzymes fostering micellization (PNLIP, CES), expression of uptake/efflux transporters (SR-BI, CD36, NPC1L1), cleavage enzymes (BCO1/2), intracellular transporters (FABP2), secretion into chylomicrons (APOB, MTTP), carotenoid metabolism in the blood and liver (LPL, APO C/E, LDLR), and distribution to target tissues such as adipose tissue or macula (GSTP1, StARD3) depend on the activity of these proteins. In addition, human microbiota, e.g. via altering bile-acid concentrations, may play a role in carotenoid bioavailability. In order to comprehend individual, variable responses to these compounds, an improved knowledge on intra-/interindividual factors determining carotenoid bioavailability, including tissue distribution, is required. Here, we highlight the current knowledge on factors that may explain such intra-/interindividual differences.

Dietary beta-carotene and lutein metabolism is modulated by the APOE genotype

The human apolipoprotein E (APOE) genotype has been suggested to interact with nutrient metabolism particularly with lipid soluble vitamins. Plasma carotenoid levels are determined by numerous dietary and genetic factors with high inter-individual variation; however, the APOE genotype has not been systematically examined so far. Our aim was to investigate the effect of the APOE genotype on dietary carotenoid metabolism with special regard to transcriptional regulation of carotenoid absorption, cleavage and adipocyte fat storage. We supplemented targeted replacement mice expressing human APOE3 and APOE4 isoforms with dietary beta-carotene (BC) and lutein (LUT) for 8 weeks. Plasma BC and adipose tissue BC and LUT levels were in trend lower in APOE4 than APOE3 mice, while hepatic expression of the beta-carotene oxygenases BCO1 and BCO2 was significantly higher. In contrast to the liver, mRNA levels of proteins involved in carotenoid absorption and cleavage in the small intestinal mucosa as well as of adipogenic markers in the adipose tissue were not different between APOE3 and APOE4 mice. Our data suggest that the hepatic carotenoid cleavage activity is higher in APOE4 mice partially reducing the circulation and extra-hepatic accumulation of intact carotenoids as compared to APOE3. Therefore we suggest considering the APOE genotype as modulator of carotenoid status in the future. © 2016 BioFactors, 42(4):388-396, 2016.

Lycopene bioavailability is associated with a combination of genetic variants

The intake of tomatoes and tomato products, which constitute the main dietary source of the red pigment lycopene (LYC), has been associated with a reduced risk of prostate cancer and cardiovascular disease, suggesting a protective role of this carotenoid. However, LYC bioavailability displays high interindividual variability. This variability may lead to varying biological effects following LYC consumption. Based on recent results obtained with two other carotenoids, we assumed that this variability was due, at least in part, to several single nucleotide polymorphisms (SNPs) in genes involved in LYC and lipid metabolism. Thus, we aimed at identifying a combination of SNPs significantly associated with the variability in LYC bioavailability. In a postprandial study, 33 healthy male volunteers consumed a test meal containing 100g tomato puree, which provided 9.7 mg all-trans LYC. LYC concentrations were measured in plasma chylomicrons (CM) isolated at regular time intervals over 8 h postprandially. For the study 1885 SNPs in 49 candidate genes, i.e., genes assumed to play a role in LYC bioavailability, were selected. Multivariate statistical analysis (partial least squares regression) was used to identify and validate the combination of SNPs most closely associated with postprandial CM LYC response. The postprandial CM LYC response to the meal was notably variable with a CV of 70%. A significant (P=0.037) and validated partial least squares regression model, which included 28 SNPs in 16 genes, explained 72% of the variance in the postprandial CM LYC response. The postprandial CM LYC response was also positively correlated to fasting plasma LYC concentrations (r=0.37, P<0.05). The ability to respond to LYC is explained, at least partly, by a combination of 28 SNPs in 16 genes. Interindividual variability in bioavailability apparently affects the long-term blood LYC status, which could ultimately modulate the biological response following LYC supplementation.

Gene polymorphisms and gene scores linked to low serum carotenoid status and their associations with metabolic disturbance and depressive symptoms in African-American adults

Gene polymorphisms provide a means to obtain unconfounded associations between carotenoids and various health outcomes. In the present study, we tested whether gene polymorphisms and gene scores linked to low serum carotenoid status are related to metabolic disturbance and depressive symptoms in African-American adults residing in Baltimore city, MD, using cross-sectional data from the Healthy Aging in Neighborhoods of Diversity across the Life Span study (age range 30-64 years, n 873-994). We examined twenty-four SNP of various gene loci that were previously shown to be associated with low serum carotenoid status (SNPlcar). Gene risk scores were created: five low specific-carotenoid risk scores (LSCRS: α-carotene, β-carotene, lutein+zeaxanthin, β-cryptoxanthin and lycopene) and one low total-carotenoid risk score (LTCRS: total carotenoids). SNPlcar, LSCRS and LTCRS were entered as predictors for a number of health outcomes. These included obesity, National Cholesterol Education Program Adult Treatment Panel III metabolic syndrome and its components, elevated homeostatic model assessment of insulin resistance, C-reactive protein, hyperuricaemia and elevated depressive symptoms (EDS, Center for Epidemiologic Studies-Depression score ≥ 16). Among the key findings, SNPlcar were not associated with the main outcomes after correction for multiple testing. However, an inverse association was found between the LTCRS and HDL-cholesterol (HDL-C) dyslipidaemia. Specifically, the α-carotene and β-cryptoxanthin LSCRS were associated with a lower odds of HDL-C dyslipidaemia. However, the β-cryptoxanthin LSCRS was linked to a higher odds of EDS, with a linear dose-response relationship. In summary, gene risk scores linked to low serum carotenoids had mixed effects on HDL-C dyslipidaemia and EDS. Further studies using larger African-American population samples are needed.

Nutrigenetics of carotenoid metabolism in the chicken: a polymorphism at the β,β-carotene 15,15'-mono-oxygenase 1 (BCMO1) locus affects the response to dietary β-carotene

The enzyme β,β-carotene-15,15'-mono-oxygenase 1 (BCMO1) is responsible for the symmetrical cleavage of β-carotene into retinal. We identified a polymorphism in the promoter of the BCMO1 gene, inducing differences in BCMO1 mRNA levels (high in adenines (AA) and low in guanines (GG)) and colour in chicken breast muscle. The present study was designed to test whether this polymorphism could affect the response to dietary β-carotene. Dietary β-carotene supplementation did not change the effects of the genotypes on breast muscle properties: BCMO1 mRNA levels were lower and xanthophyll contents higher in GG than in AA chickens. Lower vitamin E levels in the plasma and duodenum, plasma cholesterol levels and body weight were also observed in GG than in AA chickens. In both genotypes, dietary β-carotene increased vitamin A storage in the liver; however, it reduced numerous parameters such as SCARB1 (scavenger receptor class B type I) in the duodenum, BCMO1 in the liver, vitamin E levels in the plasma and tissues, xanthophyll contents in the pectoralis major muscle and carcass adiposity. However, several diet × genotype interactions were observed. In the GG genotype, dietary β-carotene increased ISX (intestine-specific homeobox) and decreased BCMO1 mRNA levels in the duodenum, decreased xanthophyll concentrations in the duodenum, liver and plasma, and decreased colour index and HDL-cholesterol concentration in the plasma. Retinol accumulation following dietary β-carotene supplementation was observed in the duodenum of AA chickens only. Therefore, the negative feedback control on β-carotene conversion through ISX appears as functional in the duodenum of GG but not of AA chickens. This could result in a higher availability of β-carotene in the duodenum of GG chickens, reducing the uptake of xanthophylls, liposoluble vitamins and cholesterol.

Serum vitamins A and E as modifiers of lipid trait genetics in the National Health and Nutrition Examination Surveys as part of the Population Architecture using Genomics and Epidemiology (PAGE) study

Both environmental and genetic factors impact lipid traits. Environmental modifiers of known genotype-phenotype associations may account for some of the "missing heritability" of these traits. To identify such modifiers, we genotyped 23 lipid-associated variants identified previously through genome-wide association studies (GWAS) in 2,435 non-Hispanic white, 1,407 non-Hispanic black, and 1,734 Mexican-American samples collected for the National Health and Nutrition Examination Surveys (NHANES). Along with lipid levels, NHANES collected environmental variables, including fat-soluble macronutrient serum levels of vitamin A and E levels. As part of the Population Architecture using Genomics and Epidemiology (PAGE) study, we modeled gene-environment interactions between vitamin A or vitamin E and 23 variants previously associated with high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride (TG) levels. We identified three SNP × vitamin A and six SNP × vitamin E interactions at a significance threshold of p < 2.2 × 10(-3). The most significant interaction was APOB rs693 × vitamin E (p = 8.9 × 10(-7)) for LDL-C levels among Mexican-Americans. The nine significant interaction models individually explained 0.35-1.61% of the variation in any one of the lipid traits. Our results suggest that vitamins A and E may modify known genotype-phenotype associations; however, these interactions account for only a fraction of the overall variability observed for HDL-C, LDL-C, and TG levels in the general population.

Genetic determinants of dietary antioxidant status

Oxidative stress refers to a physiological state in which an imbalance between pro-oxidants and antioxidants results in oxidative damage. Oxidative stress has been associated with the development of numerous chronic diseases such as type 2 diabetes, cardiovascular disease (CVD), osteoporosis, and cancer. Endogenous production of free radicals occurs during normal physiological processes, such as aerobic metabolism, oxidation of biological molecules, and enzymatic activity. Environmental factors such as ultraviolet radiation, air pollution, and cigarette smoking can also contribute to the accumulation of free radicals in the body. Excess free radicals can damage tissues and promote the upregulation of disease-related pathways such as inflammation. Modulating oxidative stress by dietary supplementation with antioxidant micronutrients such as vitamins C and E or phytochemicals such as different carotenoids may help prevent or delay the development of certain diseases. However, research on antioxidant supplementation and disease has yielded inconsistent findings, which may be due, in part, to interindividual genetic variation. Polymorphisms in genes coding for endogenous antioxidant enzymes or proteins responsible for the absorption, transport, distribution, or metabolism of dietary antioxidants have been shown to affect antioxidant status and response to supplementation. These genetic variants may also interact with environmental factors, such as diet, to determine an individual's overall antioxidant status. This chapter examines current knowledge of the relationship between genetic variation and dietary antioxidant status.

Dietary omega 3 polyunsaturated fatty acids and Alzheimer's disease: interaction with apolipoprotein E genotype

Epidemiological studies suggest a protective role of omega-3 poly-unsaturated fatty acids (n-3 PUFA) against Alzheimer's disease (AD). However, most intervention studies of supplementation with n-3 PUFA have yielded disappointing results. One reason for such discordant results may result from inadequate targeting of individuals who might benefit from the supplementation, in particular because of their genetic susceptibility to AD. The ε4 allele of the apolipoprotein E gene (ApoE) is a genetic risk factor for late-onset AD. ApoE plays a key role in the transport of cholesterol and other lipids involved in brain composition and functioning. The action of n-3 PUFA on the aging brain might therefore differ according to ApoE polymorphism. The aim of this review is to examine the interaction between dietary fatty acids and ApoE genotype on the risk for AD. Carriers of the ε4 allele tend to be the most responsive to changes in dietary fat and cholesterol. Conversely, several epidemiological studies suggest a protective effect of long-chain n-3 PUFA on cognitive decline only in those who do not carry ε4 but with inconsistent results. An intervention study showed that only non-carriers had increased concentrations of long-chain n-3 PUFA in response to supplementation. The mechanisms underlying this gene-by-diet interaction on AD risk may involve impaired fatty acids and cholesterol transport, altered metabolism of n-3 PUFA, glucose or ketones, or modification of other risk factors of AD in ε4 carriers. Further research is needed to explain the differential effect of n-3 PUFA on AD according to ApoE genotype.

Genetic influences on blood lipids and cardiovascular disease risk: tools for primary prevention

Genetic polymorphism in human populations is part of the evolutionary process that results from the interaction between the environment and the human genome. Recent changes in diet have upset this equilibrium, potentially influencing the risk of most common morbidities such as cardiovascular diseases, obesity, diabetes, and cancer. Reduction of these conditions is a major public health concern, and such a reduction could be achieved by improving our ability to detect disease predisposition early in life and by providing more personalized behavioral recommendations for successful primary prevention. In terms of cardiovascular diseases, polymorphisms at multiple genes have been associated with differential effects in terms of lipid metabolism; however, the connection with cardiovascular disease has been more elusive, and considerable heterogeneity exists among studies regarding the predictive value of genetic markers. This may be because of experimental limitations, the intrinsic complexity of the phenotypes, and the aforementioned interactions with environmental factors. The integration of genetic and environmental complexity into current and future research will drive the field toward the implementation of clinical tools aimed at providing dietary advice optimized for the individual's genome. This may imply that dietary changes are implemented early in life to gain maximum benefit. However, it is important to highlight that most reported studies have focused on adult populations and to extrapolate these findings to children and adolescents may not be justified until proper studies have been carried out in these populations and until the ethical and legal issues associated with this new field are adequately addressed.

Interactions between hepatic lipase and apolipoprotein E gene polymorphisms affect serum lipid profiles of healthy Canadian adults

The purpose of this study was to assess the individual and interactive effects between hepatic lipase (LIPC; C-514T, G-250A) and apolipoprotein E (APOE) (E2, E3, E4) gene polymorphisms on levels of plasma lipoprotein cholesterol and triglyceride among healthy, young, Canadian adults (n = 440). All subjects with at least one APOE2 allele had significantly lower low-density lipoprotein cholesterol, total cholesterol, and total cholesterol – high-density lipoprotein cholesterol ratio when compared with those with the APOE3 or APOE4 allele. There were significant differences in the LIPC allele and genotype frequencies between Caucasian (n = 207) and Asian (n = 211) individuals, but ethnicity did not contribute to the variations in circulating lipids. In addition, the lowest triglyceride levels (0.87 ± 0.27 mmol·mL–1) were found in all APOE2 individuals carrying LIPC-514-CC and LIPC-250-GG genotypes, whereas the highest triglyceride levels (1.29 ± 0.34 –1.32 ± 0.32 mmol·mL–1) were found in APOE2 individuals carrying the opposite genotypes, LIPC-514TT and LIPC-250AA. These observations, distinct from the anti-atherogenic effects of APOE2 through the lowering of low-density lipoprotein cholesterol and LIPC on high-density lipoprotein cholesterol, suggest that there is an interactive effect between APOE and LIPC genotypes on plasma triglyceride levels. These results provide the basis for further studies on establishing which genotype combinations would be the most protective against hypertriglyceridemia.

Human fasting plasma concentrations of vitamin E and carotenoids, and their association with genetic variants in apo C-III, cholesteryl ester transfer protein, hepatic lipase, intestinal fatty acid binding protein and microsomal triacylglycerol transfer protein

Plasma concentrations of vitamin E and carotenoids are governed by several factors, including genetic factors. Single nucleotide polymorphisms (SNP) in some genes involved in lipid metabolism have recently been associated with fasting plasma concentrations of these fat-soluble micronutrients. To further investigate the role of genetic factors that modulate the plasma concentrations of these micronutrients, we assessed whether SNP in five candidate genes (apo C-III,CETP,hepatic lipase,I-FABPandMTP) were associated with the plasma concentrations of these micronutrients. Fasting plasma vitamin E and carotenoid concentrations were measured in 129 French Caucasian subjects (forty-eight males and eighty-one females). Candidate SNP were genotyped by PCR amplification followed by restriction fragment length polymorphisms. Plasma γ-tocopherol, α-carotene and β-carotene concentrations were significantly different (P < 0·05) in subjects who carried different SNP variants in hepatic lipase. Plasma α-tocopherol concentrations were significantly different in subjects who had different SNP variants in apo C-III and cholesteryl ester transfer protein (CETP). Plasma lycopene concentrations were significantly different (P < 0·05) in women who had different SNP variants in intestinal fatty acid binding protein (I-FABP). Finally, there was no effect of SNP variants in microsomal TAG transfer protein upon the plasma concentrations of these micronutrients. Most of the observed differences remained significant after the plasma micronutrients were adjusted for plasma TAG and cholesterol. These results suggest that apo C-III, CETP and hepatic lipase play a role in determining the plasma concentrations of tocopherols while hepatic lipase and I-FABP may modulate plasma concentrations of carotenoids.

Association between enzymatic and non-enzymatic antioxidant defense mechanism with apolipoprotein E genotypes in Alzheimer disease

OBJECTIVE

There are evidence suggesting that APOE-varepsilon4 allele play an important role in the pathogenesis of Alzheimer's disease (AD) by reducing peripheral levels and activities of a broad spectrum of nonenzymatic and enzymatic antioxidants systems. However, the link between APOE genotype, oxidative stress, and AD has yet to be established. In this study we examined whether antioxidant defense mechanism exacerbates the risk of AD in individual carrying APOE-varepsilon4 allele in a population from Tehran, Iran.

METHOD

We determined the enzymatic activities of the erythrocyte Cu-Zn superoxide dismutase (Cu-Zn SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and serum level of total antioxidant status(TAS) in various APOE genotypes in 91 patients with AD and 91 healthy subjects as control group (age and sex-matched).

RESULT

The results showed that the TAS level and the activities of enzymatic antioxidants CAT and GSH-Px were significantly lower and the SOD activity was significantly higher in AD patients compared to controls. The AD patients with APOE-varepsilon4 allele genotype had significantly lower serum TAS concentration and lower erythrocytes GSH-Px and CAT activities (p=0.001) but significantly higher erythrocytes Cu-Zn SOD activity (p=0.001) than the non-APOE-varepsilon4 carrier AD and the control group. In addition, the association observed between the factors involved in an antioxidant defense mechanism and APOE-varepsilon4 allele in AD increased with age of the subjects.

CONCLUSION

These data indicate that the reduced serum level of TAS and activity of CAT, GSH-Px and increased SOD exacerbate the risk of AD in individuals carrying APOE-varepsilon4 allele. The reduced antioxidants defense in APOE-varepsilon4 allele carrier may contribute to beta-amyloidosis. This effect, however, is more pronounced in the AD patients older than 75 years of age. This suggests that a therapeutic modality should be considered for these subjects.

Serum alpha- and gamma-tocopherol concentrations and risk of advanced beta cell autoimmunity in children with HLA-conferred susceptibility to type 1 diabetes mellitus

AIMS/HYPOTHESIS

The aim of our study was to assess the associations of serum alpha- and gamma-tocopherol concentrations with the risk of advanced beta cell autoimmunity in children with HLA-conferred genetic susceptibility to type 1 diabetes mellitus.

METHODS

A case-control study with 108 cases with advanced beta cell autoimmunity and 216 matched control participants nested within the birth cohort of the Type 1 Diabetes Prediction and Prevention Project. A serum sample for vitamin E analyses was collected from all the children in the cohort at the age of 1 year and thereafter at 12 month intervals. For each case-control group, all the repeated serum samples up to the age of seroconversion to autoantibody positivity in the case were analysed. A conditional logistic regression model was used to determine potential associations between seroconversion and serum tocopherol concentrations.

RESULTS

Serum alpha- or gamma-tocopherol concentrations were not significantly associated with the risk of advanced beta cell autoimmunity. The odds ratio (95% CI) for micromol/l increase in serum concentration of the first-year sample was 0.97 (0.92-1.03) for alpha-tocopherol and 1.10 (0.70-1.74) for gamma-tocopherol. However, there was an interaction between high values of gamma-tocopherol at the age of 1 year and the time of seroconversion (p = 0.024).

CONCLUSIONS/INTERPRETATION

It seems unlikely that high concentrations of alpha- or gamma-tocopherol protect against advanced beta cell autoimmunity in young children.

Deletion of apolipoprotein E gene modifies the rate of depletion of alpha tocopherol (vitamin E) from mice brains

Our previous reports show that apolipoprotein E (apoE) influences the dynamics of alpha tocopherol (vitamin E) in brain. In this investigation, the patterns of depletion of alpha tocopherol from tissues of apoE deficient and wild type mice were compared after the animals were fed vitamin E deficient diets. Alpha tocopherol concentrations in specific regions of the brain and peripheral tissues at different times were determined by HPLC with electrochemical detection. ApoE deficiency significantly retarded the rate of depletion of alpha tocopherol from all regions of the brain. In addition, comparison of the rates of depletion of alpha tocopherol in both apoE deficient and wild type animals showed that cerebellum behaved differently from other areas such as cortex, hippocampus and striatum. This reinforces the uniqueness of cerebellum with regard to vitamin E biology. Patterns of depletion of tocopherol from peripheral tissues were different from brain. Serum tocopherol was higher in apoE deficient animals and remained higher than wild type during E deficiency. Depletion of liver tocopherol also tended to be unaffected by apoE deficiency. Our current and previous observations strongly suggest that apoE has an important role in modulating tocopherol concentrations in brain, probably acting in concert with other proteins as well.

Human plasma levels of vitamin E and carotenoids are associated with genetic polymorphisms in genes involved in lipid metabolism

Vitamin E and carotenoids are fat-soluble micronutrients carried by plasma lipoproteins. Their plasma concentrations are governed by several factors, some of which are genetic, but data on these genetic factors remain scarce. We hypothesized that genes involved in lipid metabolism, i.e. the genes implicated in intestinal uptake, intracellular trafficking, and the lipoprotein distribution of lipids, play a role in the plasma concentrations of these micronutrients. To verify this hypothesis, we assessed whether the plasma status of vitamin E and carotenoids is related to genes involved in lipid metabolism. Fasting plasma vitamin E (alpha- and gamma-tocopherol) and carotenoid (alpha- and beta-carotene, lutein, lycopene, beta-cryptoxanthin, and zeaxanthin) concentrations were measured in 48 males and 80 females. The following genes were genotyped [single nucleotide polymorphisms (SNP)]: apolipoprotein (apo) A-IV, apo B, apo E, lipoprotein lipase, and scavenger-receptor class B type I (SR-BI). Plasma alpha-tocopherol concentrations were different (P < 0.05) in subjects bearing different SNP in apo A-IV, apo E, and SR-BI. Plasma gamma-tocopherol concentrations were different (P < 0.05) in subjects bearing different SNP in apo A-IV and SR-BI. Alpha-carotene concentrations were different (P < 0.05) in subjects bearing different SNP in SR-BI. Beta-carotene concentrations were different (P < 0.05) in subjects bearing different SNP in apo B and SR-BI. Lycopene concentrations were different (P < 0.05) in subjects bearing different SNP in apo A-IV and apo B. Beta-cryptoxanthin concentrations were different (P < 0.05) in subjects bearing different SNP in SR-BI. Plasma lutein and zeaxanthin concentrations did not differ in subjects bearing different SNP. Most of the differences remained significant after the plasma micronutrients were adjusted for plasma triglycerides and cholesterol. These results suggest that genes involved in lipid metabolism influence the plasma concentrations of these fat-soluble micronutrients.

Nonsupplemented children of Latino immigrants have low vitamin E intakes and plasma concentrations and normal vitamin C, selenium, and carotenoid intakes and plasma concentrations

OBJECTIVE

This study sought to determine and evaluate the intakes and plasma concentrations of vitamin E (alpha-tocopherol), gamma-tocopherol, vitamin C, selenium, and carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin, and lycopene) of nonsupplemented boys and girls, 4 to 8 years old, of Latino immigrants living in rural Nebraska.

DESIGN

Dietary intakes of the Latino children were estimated. Their plasma samples (fasting) were analyzed for vitamin E, vitamin C, selenium, and carotenoid concentrations. Data were evaluated by sex.

SUBJECTS

The subjects were a convenience sample of 4- to 8-year-old (n=29), apparently healthy, nonsupplemented children of Latino immigrants living in rural Nebraska.

STATISTICAL ANALYSIS

Sex differences in parameter values were determined using general linear models; Pearson r was used for determining correlations.

RESULTS

No significant differences in parameter values were observed by sex, with the exception of plasma lutein/zeaxanthin concentration. The majority (69%) had plasma vitamin E (alpha-tocopherol) concentrations<0.516 mg/dL (12 micromol/L), which is indicative of vitamin E inadequacy, and over half (59%) reported consuming less than the Estimated Average Requirement for vitamin E. All subjects had plasma vitamin C and selenium concentrations indicative of adequacy (>0.41 mg/dL or >23 micromol/L, and >6.32 microg/dL or >0.8 micromol/L, respectively), and consumed at least the Recommended Dietary Allowances for these nutrients. The plasma carotenoid concentrations of the children may be useful as norms.

CONCLUSIONS

These children of Latino immigrants who did not take supplements had low plasma vitamin E (alpha-tocopherol) concentrations but normal plasma vitamin C and selenium concentrations.

IMPLICATIONS

Dietetics professionals and others involved in health care need to work with Latino immigrant parents so that their children consume adequate amounts of vitamin E.