Association of apolipoprotein genetic polymorphisms with plasma cholesterol in a Japanese rural population. The Shibata Study

ApoB gene polymorphism (rs676210) and its pharmacogenetics impact on atorvastatin response among Iraqi population with coronary artery disease

Background

Drug response is below genetic influence, proven by the genetic variants. Pharmacogenetics trials are performed in many diseases, including coronary artery disease. This study was designed to determine the genetic polymorphism (rs676210) Pro2739leu G > A in the lipid metabolism-related gene (ApoB gene) and its pharmacogenetic role in the response to atorvastatin drug in a sample of Iraqi population with coronary artery disease (CAD).

Results

Significant differences of genotype distribution in CAD patients and controls were observed in ApoB_+ 8216 in Iraqi population from Hardy Weinberg Analysis. It also found that dramatic difference of low-density lipoprotein (LDL-C) level in response to 40 mg/day of atorvastatin therapy, the minor allele (A) observed a greater LDL-C lowering than the wild type allele (G). In ANOVA analysis, the result showed that the rs676210, Pro2739Leu, in ApoB gene increased non significantly, but gradually in plasma level of total cholesterol (TC), triglyceride (TG), very low-density lipoprotein (VLDL), and oxidize low-density lipoprotein (oxLDL) in the order of genotype AA, GA, and GG in response to 40 mg atorvastatin.

Conclusion

We found the results highlighted the function of the rs676210, Pro2739Leu, in the ApoB gene in CAD etiology, and the findings support this variant’s impact in predicting the response of (LDL-C) to 40 mg of atorvastatin therapy. ApoB gene polymorphism (rs676210, Pro2739Leu), specifically the AA genotype, may help to identify individuals who will profit from atorvastatin's lowering effects.

Distribution of polymorphism rs693 of ApoB gene in a sample of Colombian Caribbeans

INTRODUCTION

Several studies have reported that the single nucleotide polymorphism rs693 of Apo lipoprotein B gene is associated with high levels of plasma lipids and high body mass index, which are risk factors for cardiovascular diseases. The distribution of this single nucleotide polymorphism and its association with the phenotype depend on the genetic background of each population.

OBJECTIVE

To evaluate the distribution of single nucleotide polymorphism rs693 and its association with lipid profile and body mass index in a sample of Colombian Caribbeans.

METHODS

108 non-related adult subjects of both gender were included in this study. Body mass index and lipid profile that included total cholesterol, triglycerides, Low Density Lipoprotein and High Density Lipoprotein were determined. The single nucleotide polymorphism rs693 was determined by Polymerase Chain Reaction/Restriction Fragment Length Polymorphism from genomic DNA followed by digestion with the restriction enzyme XbaI. The chi-square test was used to analyze the genotype distribution of rs693 and the genotype-phenotype association was evaluated through different inheritance model.

RESULTS

The genotype frequencies for single nucleotide polymorphism rs693 were CC (45.0%), TT (16.5%) and CT (38.5%). The allele frequencies were C (64.0%) and T (36.0%). The single nucleotide polymorphism was in Hardy-Weinberg equilibrium in the studied sample. No association of the single nucleotide polymorphism rs693 with lipid profile nor the body mass index was found (p >0.05).

CONCLUSION

There is no significant association between single nucleotide polymorphism rs693 and body mass index nor lipid profile, in a sample of Colombian Caribbeans.

Global genetic diversity of human apolipoproteins and effects on cardiovascular disease risk

Abnormal plasma apolipoprotein levels are consistently implicated in CVD risk. Although 30% to 60% of their interindividual variability is genetic, common genetic variants explain only 10% to 20% of these differences. Rare genetic variants may be major sources of the missing heritability, yet quantitative evaluations of their contribution to phenotypic variability are lacking. Here, we analyzed whole-genome and whole-exome sequencing data from 138,632 individuals across seven major human populations to present a systematic overview of genetic apolipoprotein variability. We provide population-specific frequencies of 38 clinically important apolipoprotein alleles and identify further 6,875 genetic variants, 33% of which are novel and 98.7% of which are rare with minor allele frequencies <1%. We predicted the functional impact of rare variants and found that their relative importance differed drastically between genes and among ethnicities. Importantly, we validated the clinical relevance of multiple variants with predicted effects by leveraging association data from the CARDIoGRAM (Coronary Artery Disease Genomewide Replication and Meta-analysis) and Global Lipids Genetics consortia. Overall, we provide a consolidated overview of population-specific apolipoprotein genetics as a valuable data resource for scientists and clinicians, estimate the importance of rare genetic variants for the missing heritability of apolipoprotein-associated disease traits, and pinpoint multiple novel apolipoprotein variants with putative population-specific impacts on serum lipid levels.

No change of the lipid profile under the control of ApoE gene polymorphism in schizophrenics under paliperidone treatment

The present study tried to explore the effects of Paliperidone on the lipid profiles of schizophrenia patients. One hundred twenty-nine subjects diagnosed with schizophrenia were enrolled into this study and completed the lipid profile evaluation. Their blood samples were obtained on the morning following a 12-hours fast. Cholesterol and triglyceride (TG) levels in plasma were determined, and lipoproteins were determined by enzymatic methods. All participants provided written informed consent, and underwent additional venous blood withdrawal for DNA extraction for genetic study of the ApoE gene polymorphism. Under T test, TC, TG and HDL levels all declined after Paliperidone treatment although with no statistically significant difference. The ratios of TC/HDL declined after Paliperidone treatment, but without statistically significant difference. After GEE-I analysis, we found that ApoE4 genotype (β = 34.471; p < 0.001) had a positive effect on the total cholesterol (TC) level; female had positive effect on the high-density lipoprotein (HDL) level (β = 15.361; p = 0.003); and age had a positive effect on the TG level (β = 1.317; p = 0.030). Smoking (β = 0.961; p = 0.016) had a positive effect on the ratio of TC/HDL change. Lipid profiles were not increased after Paliperidone treatment under the control of ApoE gene polymorphism.

Genetic association of APOB polymorphisms with variation in serum lipid profile among the Kuwait population

BACKGROUND

Several studies have identified APOB as a candidate gene predisposing individuals to dyslipidemia. Polymorphisms including the signal peptide (rs11279109), codon 2488 XbaI (rs1042031), codon 3611 MspI (rs693), codon 4154 EcoRI (rs1801701) and the 3' variable number of tandem repeats have been reported to be associated with dyslipidemia in several populations. With limited studies on Arabs, this study aimed to investigate the genetic association of APOB polymorphisms and assess the potential influence of minor and rare alleles on serum lipid levels in the Kuwaiti population.

METHODS

A total of 795 Kuwaiti subjects, documented with phenotypic data and fasting serum lipid levels, were genotyped for the five polymorphisms using PCR, PCR-RFLP and gene fragment analysis. Genotype and allele association with variation in serum lipid levels as well as haplotypes were analyzed using chi-square test, univariate and logistic regression analysis.

RESULTS

Analysis of the genotype and allele frequencies distribution revealed a significant positive association between the APOB signal peptide and 3611 MspI polymorphisms with increased levels of triglycerides (statistical power of 80%). Haplotype analysis further supported the findings by showing that carriers of haplotypes (IX-M-E+M) had significantly lower mean (SD) TG levels (0.86 ± 0.07) as compared to non-carriers (1.01 ± 0.02). Significance was also observed with regards to positive family history of hypercholesterolemia.

CONCLUSION

The results imply a "protective role" for two alleles (rs11279109 and rs1801701) in which logistic regression analysis showed a significant half-fold decrease in the risk for heterozygotes of rs11279109 and an 8.8 fold decrease in the risk for homozygous M-M- of rs1801701 of having lower TG levels (<1.70 mmol/L) in individuals. This suggests that genetic interaction between various polymorphisms at different gene loci act in linkage disequilibrium to affect serum TG levels. Apo B genotyping may be a useful adjunct for the identification of individuals at risk of developing dyslipidemia in order to provide them with lifestyle modifications and/or pharmacological intervention to mitigate the effects of gene interaction and environmental influence.

ApoE isoforms, treatment of diabetes and the risk of coronary heart disease

AIM

To analyze the risk of coronary heart disease in patients with type 2 diabetes mellitus (T2DM) receiving standard medical treatment.

METHODS

We performed a retrospective chart analysis of 269 middle-aged patients (age 45-64 years, mean age, 53.9 ± 5.5 years) with T2DM and without atherosclerotic cardiovascular events who underwent typing to determine their apolipoprotein E (apoE) isoforms. The apoE isoforms were determined using isoelectric focusing, followed by immunoblotting. We retrospectively evaluated the charts of the 269 patients, recorded between their first visit to the hospital (the study's start point, between 1987 and 1992) and the occurrence of an atherosclerotic cardiovascular event (the study's endpoint) or January 2004, whichever came first. The age-adjusted mean values and the prevalences of covariates were calculated to compare the laboratory data among the apoE phenotypes. To investigate the association of risk factors with the incidence of coronary heart disease during the follow-up period, monovariate and multivariate Cox regression models were used.

RESULTS

At enrollment, the mean serum low density lipoprotein (LDL) cholesterol levels were lowest (2.92 ± 0.89 mmol/L) among the subjects with apoE2 (apoE2/2 or apoE2/3) and highest (3.52 ± 0.77 mmol/L) among the subjects with apoE4 (apoE3/4 or apoE4/4). No significant differences in mean age or the percentage of smokers were observed among the three groups. Furthermore, no significant differences were observed in the systolic and diastolic blood pressures, body mass index, HbA1c level or serum triglyceride levels among the three groups. There were 47 cases of coronary heart disease over 3285 person-years of follow-up. An age-adjusted multivariate Cox proportional model identified diabetic retinopathy (hazard ratio, 2.38, 95% CI: 1.28-4.43, P = 0.006), a high systolic blood pressure (hazard ratio, 1.04, 95% CI: 1.02-1.06, P < 0.001) and high HbA1c values (hazard ratio, 1.19, 95% CI: 1.02-1.38, P = 0.0029), but not the LDL cholesterol value at enrollment (hazard ratio, 1.01, 95% CI: 0.97-1.05, P = 0.77) nor the specific apoE isoform, as significant predictors of coronary heart disease.

CONCLUSION

Under standard medical treatment of diabetes, including the control of LDL cholesterol levels, the apoE4 isoform was not associated with coronary heart disease among T2DM patients.

Polymorphism of the apolipoprotein B gene and association with plasma lipid and lipoprotein levels in the Mongolian Buryat

Allele frequencies at six RFLP sites (Ins/Del, ApaLI, AluI, XbaI, MspI, and EcoRI) of the apolipoprotein B gene (APOB) and the relationship of genotypes with plasma lipid and lipoprotein levels in the Mongolian Buryat were investigated. Common alleles at these sites in 110 Buryat subjects were I, G, A-, X-, M+, and E+; the frequencies of 0.809-0.991 differed strikingly from those of a few Asians and most Europeans. Five unambiguous haplotypes of all sites were revealed at 74%; haplotype IGA-X-M+E+ (000000) was the most frequent (67%), followed by IGA+X-M+E+ (001000) (19%). The frequency constitution differed significantly from the Chinese, Malaysians, and Caucasians but resembled the Indians. No APOB polymorphisms were associated with cholesterol levels (total, HDL and LDL). Significant associations of genotypes were shown with the triglyceride level only at the AluI and XbaI sites. The lipid level of A-A+ females or X-X+ males was higher than that of A-A- females or X-X- males, respectively.

Apolipoprotein B genetic variants modify the response to fenofibrate: a GOLDN study

Hypertriglyceridemia, defined as a triglyceride measurement > 150 mg/dl, occurs in up to 34% of adults. Fenofibrate is a commonly used drug to treat hypertriglyceridemia, but response to fenofibrate varies considerably among individuals. We sought to determine if genetic variation in apolipoprotein B (APOB), an essential core of triglyceride-rich lipoprotein formation, may account for some of the inter-individual differences observed in triglyceride (TG) response to fenofibrate treatment. Participants (N = 958) from the Genetics of Lipid Lowering Drugs and Diet Network study completed a three-week intervention with fenofibrate 160 mg/day. Associations of four APOB gene single nucleotide polymorphisms (SNP) (rs934197, rs693, rs676210, and rs1042031) were tested for association with the TG response to fenofibrate using a mixed growth curve model where the familial structure was modeled as a random effect and cardiovascular risk factors were included as covariates. Three of these four SNPs changed the amino acid sequence of APOB, and the fourth was in the promoter region. TG response to fenofibrate treatment was associated with one APOB SNP, rs676210 (Pro2739Leu), such that participants with the TT genotype of rs676210 had greater TG lowering than those with the CC genotype (additive model, P = 0.0017). We conclude the rs676210 variant may identify individuals who respond best to fenofibrate for TG reduction.

Hypervariability in a minisatellite 3' of the apolipoprotein B gene: allelic distribution and influence on lipid profiles in Han Children from central China

BACKGROUND

Apolipoprotein B (apoB) gene 3' variable number tandem repeat (VNTR) is highly variable, and thereby be considered as an informative marker for associative analysis of lipid metabolism.

METHODS

We conducted this study to probe the effect of apoB 3' VNTR alleles on lipid profiles in 500 Han children from central China, and to compare the allelic distribution of our subjects with multiple Chinese populations. 14 different alleles of the apoB gene 3' VNTR comprising from HVE22 to HVE44 were identified in our subjects.

RESULTS

Allele size distribution followed unimodal curve with the main peak at HVE35 (58.0%). We detected 37 genotypes in this sampling, the most frequently seen was HVE35/35 with a frequency of 36.4%. M/L carriers had significantly higher total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) and apoB concentrations than did S/S, M/M or S/M carriers (p<0.05). Individuals with L allele exhibited significantly higher TC, LDL-C, and apoB levels than those with M or S allele (p<0.05). The allelic distribution in Central Han Chinese differed from Southern Han Chinese (X(2)=41.2, p=0.00), Zhuang Chinese (X(2)=65.4, p=0.00), and Uighur Chinese (X(2)=45.6, p=0.00). No significant differences in allelic frequencies were observed for apoB 3' VNTR in Central Han Chinese as compared to Northern Han Chinese (X(2)=2.5, p=0.29).

CONCLUSION

This study identified the higher repeat alleles as potential risk factor for dyslipidemia in Han children from Central China. Although five Chinese populations demonstrated uniformly unimodal distributions of allelic frequencies with the main peaks at HVE32-HVE37, there was obvious heterogeneity among these populations.

APOE distribution in world populations with new data from India and the UK

BACKGROUND

The APOE gene and its protein product is associated with a number of plasma proteins like very-low density lipoprotein (VLDL), high density lipoprotein (HDL) chylomicrons, chylomicron remnants, and plays a crucial role in lipid metabolism. The APOE gene is polymorphic and common alleles (*E2, *E3 and *E4) have been associated with a number of common and complex diseases in different populations. Due to their crucial role in metabolism and clinical significance, it is imperative that allelic variation in different populations is analysed to evaluate the usage of APOE in an evolutionary and clinical context.

AIM

We report allelic variation at the APOE locus in three European and four Indian populations and evaluate global patterns of genetic variation at this locus. The large, intricate and unexpected heterogeneity of this locus in its global perspective may have insightful consequences, which we have explored in this paper.

SUBJECT AND METHODS

Apolipoprotein E genotypes were determined in four population groups (Punjabi Sikhs, Punjabi Hindus, Maria Gonds and Koch, total individuals = 497) of India and three regionally sub-divided British populations (Nottinghamshire, East Midlands and West Midlands, total individuals = 621). The extent and distribution of APOE allele frequencies were compared with 292 populations of the world using a variety of multivariate methods.

RESULTS

Three alleles, APOE*E2, APOE*E3 and APOE*E4, were observed with contrasting variation, although *E4 was absent in the tribal population of Koch. Higher heterozygosities (>43%) in British populations reflected their greater genetic diversity at this locus. The overall pattern of allelic diversity among these populations is comparable to many European and Indian populations. At a global level, higher frequencies of the *E2 allele were observed in Africa and Oceania (0.099 +/- 0.083 and 0.111 +/- 0.052, respectively). Similarly, *E4 allele averages were higher in Oceania (0.221 +/- 0.149) and Africa (0.209 +/- 0.090), while Indian and Asian populations showed the highest frequencies of *E3 allele. The coefficient of gene differentiation was found to be highest in South America (9.6%), although the highest genetic diversity was observed in Oceania (48.7%) and Africa (46.3%). APOE*E2 revealed a statistically significant decreasing cline towards the north in Asia (r = -0.407, d.f. = 70, p < 0.05), which is not compatible with the coronary heart disease statistics in this continent. APOE*E4 showed a significant increasing cline in North European populations. Spatial autocorrelation analysis shows that the variation at this locus is influenced by 'isolation by distance' with a strong positive correlation for lower distances up to 1313 km.

CONCLUSION

Overall APOE allelic variation in UK and Indian populations is comparable to previous studies but in tribal populations *E4 allele frequency was very low or absent. At a global level allelic variation shows that geography, isolation by distance, genetic drift and possibly pre-historical selection are responsible for shaping the spectrum of genetic variation at the APOE gene. Overall, APOE is a good anthropogenetic and clinical diagnostic marker.

Genetic-epidemiological evidence on genes associated with HDL cholesterol levels: a systematic in-depth review

High-density lipoprotein (HDL) particles exhibit multiple antiatherogenic effects. They are key players in the reverse cholesterol transport which shuttles cholesterol from peripheral cells (e.g. macrophages) to the liver or other tissues. This complex process is thought to represent the basis for the antiatherogenic properties of HDL particles. The amount of cholesterol transported in HDL particles is measured as HDL cholesterol (HDLC) and is inversely correlated with the risk for coronary artery disease: an increase of 1mg/dL of HDLC levels is associated with a 2% and 3% decrease of the risk for coronary artery disease in men and women, respectively. Genetically determined conditions with high HDLC levels (e.g. familial hyperalphalipoproteinemia) often coexist with longevity, and higher HDLC levels were found among healthy elderly individuals. HDLC levels are under considerable genetic control with heritability estimates of up to 80%. The identification and characterization of genetic variants associated with HDLC concentrations can provide new insights into the background of longevity. This review provides an extended overview on the current genetic-epidemiological evidence from association studies on genes involved in HDLC metabolism. It provides a path through the jungle of association studies which are sometimes confusing due to the varying and sometimes erroneous names of genetic variants, positions and directions of associations. Furthermore, it reviews the recent findings from genome-wide association studies which have identified new genes influencing HDLC levels. The yet identified genes together explain only a small amount of less than 10% of the HDLC variance, which leaves an enormous room for further yet to be identified genetic variants. This might be accomplished by large population-based genome-wide meta-analyses and by deep-sequencing approaches on the identified genes. The resulting findings will probably result in a re-drawing and extension of the involved metabolic pathways of HDLC metabolism.

Low adiponectin state is associated with metabolic abnormalities in obese children, particularly depending on apolipoprotein E phenotype

Background

Adiponectin links obesity with insulin resistance, which causes various metabolic abnormalities including dyslipidaemia. Apolipoprotein E (apoE) phenotypes also affect lipoprotein profiles. We aimed to determine whether low adiponectin concentrations are associated with insulin resistance and downstream metabolic abnormalities in obese children.

Methods

We measured fasting concentrations of lipids, apoE, glucose, insulin and adiponectin, as well as anthropometric parameters, in 191 obese children aged 6–15 years. ApoE phenotypes were determined by isoelectric focusing. Boys ( n = 79) and girls ( n = 39) with apoE3/3 were classified into tertiles according to their adiponectin concentrations. Metabolic parameters, were compared among these three groups in boys and girls separately.

Results

The low adiponectin groups had higher median homeostasis model assessment of insulin resistance (HOMA-IR) than the middle and high adiponectin groups in both boys [5.3 (low) versus 3.1 (middle; P < 0.05) and 3.5 (high; P < 0.05)] and girls [5.0 (low) versus 4.4 (middle) and 3.0 (high; P < 0.05)]. However, only boys who were in the low adiponectin group exhibited significantly higher concentrations of blood pressure, triglycerides, LDL-cholesterol, and remnant-like particle-cholesterol, and lower concentrations of HDL-cholesterol compared with the middle or high adiponectin groups.

Conclusion

Low adiponectin concentration is associated with insulin resistance in obese children. Furthermore, decreased adiponectin with E3/3 exhibited more prominent downstream metabolic abnormalities in obese boys than in obese girls.

Apolipoprotein E polymorphism in normal Han Chinese population: frequency and effect on lipid parameters

Apolipoprotein E (ApoE) genotypes were studied in order to determine the prevalence and effect on lipid parameters in normal Han Chinese population. Fragments of ApoE gene forth exon containing codon 112 and 158 polymorphic locus were amplified by PCR, and then digested with Cfo I endonuclease. Genotypes and alleles frequencies of 168 healthy Han Chinese were calculated. The frequency of genotypes epsilon3/3, epsilon3/4, and epsilon2/3 was found to be 75.00, 10.70, and 11.90%, respectively, and 0.60, 1.20, and 0.60% for epsilon2/2, epsilon2/4, and epsilon4/4. The effects of ApoE genotypes and alleles on lipid parameters were analyzed. The effects of ApoE alleles on TC, LDL-C, ApoB was: along a decreasing gradient epsilon4 > epsilon3 > epsilon2. The effect of epsilon4 allele was to increase serum levels of TC, LDL-C and ApoB, and epsilon2 allele had an effect opposite to that of epsilon4 allele. Results obtained in this study indicate that ApoE polymorphism is an independent genetic factor on individual serum levels of lipids and apolipoproteins.

Haplotype analysis of signal peptide (insertion/deletion) and XbaI polymorphisms of the APOB gene in gallbladder cancer

PURPOSE

The incidence of gallbladder cancer (GBC) is usually paralleled by the prevalence of gallstone disease, and genes of cholesterol metabolism have been implicated in gallstone disease. The XbaI and insertion/deletion (ins/del) polymorphism of Apolipoprotein B (APOB) appears to influence cholesterol homoeostasis and possibly risk for gallstone disease. We examined the effect of these polymorphisms individually as well as their haplotypes on GBC and gallstone patients in North Indian population.

METHODS

The study comprises 123 consecutive cases of proven GBC, 172 cases of gallstone and 232 healthy subjects of similar age and sex. The genomic DNA was extracted from peripheral blood leucocytes and genotyping was performed using polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism.

RESULTS

In a case-control study, APOB XbaI and ins/del polymorphisms were not significantly associated with risk of GBC. Using the expectation maximization algorithm, four haplotypes were obtained, and haplotype X(+),D was found to be significantly higher in GBC patients without stone in comparison with healthy subjects [odds ratio (OR) 2.9, 95% confidence interval 1.2-6.6 P=0.012].

CONCLUSIONS

The X(+),D haplotype of APOB is associated with increased risk for development of GBC and the risk is not modified in the presence of gallstones.

Differences in the Association Between Apolipoprotein E Genotype and Mortality Across Populations

BACKGROUND

The gene for apolipoprotein-E (APOE) has three common alleles (epsilon2, epsilon3, and epsilon4) that have been shown to be associated with differences in the risk of death in persons older than 60 years in European populations. However, previous research suggests that they may not be associated with mortality in African Americans, and the evidence in Asians is mixed. It is now possible to examine the effects of these genotypes on mortality in African American, Chinese, Japanese, and Korean populations.

METHODS

The analysis is based on two types of published data: genotype by age and mortality by genotype. Demographic synthesis uses a multistate model to combine data from these case-control and cohort studies to provide maximum likelihood estimates of the relative risks of death.

RESULTS

In general, the APOE epsilon2 allele is associated with 5%-10% lower mortality than the epsilon3/3 genotype. The epsilon4/4 allele is generally associated with a moderately high relative risk of death. The epsilon3/4 genotype is associated with 22% excess risk in Europeans and U.S. whites and with about 35% in Chinese. However, there is no evidence of excess risk with epsilon3/4 among African Americans and little excess risk among Japanese and Koreans. The relationship between genotype and mortality is consistent within these ethnic groups. For example, the estimates of R(3/4) for Japanese in Japan and Hawaii are both low, and the estimates for Chinese in Taiwan and Shanghai are relatively high.

CONCLUSIONS

. The relationship between APOE genotype and mortality differs across population groups but shows little evidence of variation within groups.

ApoB C7623T polymorphism predicts risk for steroid-induced osteonecrosis of the femoral head after renal transplantation

BACKGROUND

Nontraumatic osteonecrosis of the femoral head (ONFH) is caused by disruption of blood flow. This disease often occurs in association with steroid treatment. The pathology of steroid-induced ONFH remains unclear, although abnormalities in lipid metabolism have been reported to be involved. In this study, we examined the differences of gene polymorphism frequencies of apolipoprotein B (ApoB) and apolipoprotein A1 (ApoA1), which are important proteins for lipid transport, as well as of lipid parameters, between ONFH cases and referent patients among those who were subjected to renal transplantation.

METHODS

Subjects were 158 cases who had undergone renal transplant, including 34 cases that were diagnosed as ONFH after renal transplantation and 124 cases that were not. Four single nucleotide polymorphisms including C7623T and G12619A for the ApoB gene and G75A and C83T for the ApoA1 gene were analyzed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and Taqman real-time PCR chemistry. Also, serum levels of low-density lipoprotein (LDL), high-density lipoprotein (HDL), ApoB, and ApoA1 were measured. Their relationship to ONFH was statistically evaluated.

RESULTS

A higher frequency of 7623TT or CT of the ApoB gene was observed in ONFH cases than in referent patients (P = 0.033), resulting in an elevated odds ratio that was statistically significant (adjusted odds ratio = 6.37, 95% CI = 1.53-26.5, P = 0.011). No significant relationship was observed between other genes and ONFH. Regarding lipid parameters, a higher value of ApoB/ApoA1 ratio was observed in cases (P = 0.045).

CONCLUSION

For the prediction of ONFH, it is useful to analyze ApoB C7623T and plasma ApoB/ApoA1 ratio before the administration of steroids.

Plasma lipids in a rural population of Bangladesh

BACKGROUND

Plasma lipids are associated with cardiovascular diseases. Population-based data on plasma lipids are scarce in Bangladesh.

METHODS

We investigated plasma lipid levels in a rural population of Bangladesh in 2001. Fasting blood was collected in 447 adults (157 men and 290 women) aged 20-79 years (mean+/-standard deviation 40+/-11 years in men, and 39+/-10 in women).

RESULTS

The mean total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides and total cholesterol/HDL cholesterol ratio levels were 182+/-56, 39+/-10, 115+/-53, 139+/-72 mg/dl and 4.8+/-1.8, respectively. The prevalence of abnormal lipid levels were as follows: hypercholesterolemia (total cholesterol > or =240 mg/dl) 16.1%, high LDL cholesterol (> or =160 mg/dl) 20.4%, low HDL cholesterol (<40 mg/dl) 66.4%, hypertriglyceridemia (> or =200 mg/dl) 15.0% and total cholesterol/HDL cholesterol ratio (>5.5) 32.7%.

CONCLUSIONS

The prevalence of dyslipidemias, especially in the case of low HDL cholesterol, appears to be high even in this rural population of Bangladesh.

Common variants of multiple genes that control reverse cholesterol transport together explain only a minor part of the variation of HDL cholesterol levels

It is assumed that the combined effects of multiple common genetic variants explain a large part of variation of high-density lipoprotein cholesterol (HDL-C) plasma levels, but little evidence exists to corroborate this assumption. It was our objective to study the contribution of multiple common genetic variants of HDL-C-related genes to variation of HDL-C plasma levels. A well-characterized cohort of 546 Caucasian men with documented coronary artery disease was genotyped for common functional variants in genes that control reverse cholesterol transport: ATP-binding cassette transporter A1, apolipoprotein A-I and apolipoprotein-E, cholesteryl ester transfer protein, hepatic lipase, lecithin : cholesterol-acyl transferase, lipoprotein lipase, and scavenger receptor class B type 1. Multivariate linear regression showed that these variants, in conjunction, explain 12.4% (95% confidence interval: 6.9-17.9%) of variation in HDL-C plasma levels. When the covariates smoking and body mass index were taken into account, the explained variation increased to 15.3% (9.4-21.2%), and when 10 two-way interactions were incorporated, this percentage rose to 25.2% (18.9-31.5%). This study supports the hypothesis that multiple, mildly penetrant, but highly prevalent genetic variants explain part of the variation of HDL-C plasma levels, albeit to a very modest extent. Multiple environmental and genetic influences on HDL-C plasma levels still have to be elucidated.

A Module Map Showing Interaction between Apolipoprotein E and Phospholipase A2 Polymorphism in Lipid Profiles

OBJECTIVE

Establish a possible conceptual relationship among Apo E and PLA2 polymorphism and lipid profiles.

METHODS

Five hundred subjects aged 65 to 74 years were randomly selected from a community in southern Taiwan to assess the relationship between Apo E and PLA2 polymorphisms and lipid profiles. Two hundred fifty-six participants agreed to have venous blood drawn for DNA studies.

RESULTS

By multiple linear regression, the PLA2 A2 allele showed a statistically significant influence on LDL-C (p = 0.0097), and the Apo epsilon2 allele showed a statistically significant influence on HDL-C (p = 0.0004), however, the interaction between the PLA2 A2 allele and the Apo epsilon2 allele was found to be significant in the blood fraction of HDL-C (p = 0.0388) and LDL-C (p = 0.0002). Decreasing HDL-C and increasing LDL-C were found when the PLA2 A2 and Apo epsilon2 allele co-existed.

CONCLUSION

The presence of a physiologic balance contributes significantly to homeostatic and compensatory responses regulating blood HDL-C and LDL-C profiles. A module map of the generation-control cycle and conditional activity among Apo E, PLA2, and lipid levels is presented, and both behaviours and biological perspectives under the consilience model may suggest a new approach to many kinds of complex disorders.

Gender- and age-specific contributions of additional DNA sequence variation in the 5' regulatory region of the APOE gene to prediction of measures of lipid metabolism

In the present study of 9,000 individuals representative of the general population, we have considered whether the addition of common single nucleotide polymorphisms (SNPs) in the promoter region of Apolipoprotein E (APOE) improve the statistical explanation of variation in lipid traits and test the hypothesis that the estimated genotype effects are independent of factors indexed by gender and age. To address these questions, we have asked, for each gender and for each 20-year age strata (young: 20-39 years; middle-aged: 40-59 years; old: 60-79 years; very old: 80-100 years), how much trait variation is associated with the traditional epsilon2, epsilon3, and epsilon4 allelic variations defined by the g.2059T --> C and g.2197C --> T SNPs in the fourth exon of the APOE gene, and how much additional trait variation is associated with genotypes defined by combining the g.2059T --> C and g.2197C --> T SNPs with one, two, or three promoter SNPs. Our study demonstrates that the pleiotropic effects of genotype variation defined by the traditional epsilon2, epsilon3, and epsilon4 alleles on five plasma measures of lipid metabolism manifest differently in women and men and change significantly during the life cycle for high-density lipoprotein cholesterol in women. Multi-site genotypes defined by adding SNPs located in the 5' promoter region to the traditional g.2059T --> C and g.2197C --> T SNPs doubled the estimate of genetic variance of high-density lipoprotein and apolipoprotein Al in middle-aged females.

An association analysis between ApoA1 polymorphisms and the high-density lipoprotein (HDL) cholesterol level and myocardial infarction (MI) in Japanese

Association studies were performed to confirm the effect of polymorphisms in apolipoprotein A1 ( ApoA1) on the high-density lipoprotein cholesterol (HDL-C) level and the incidence of myocardial infarction (MI). A sequence analysis identified nine polymorphisms in ApoA1. After considering linkage disequilibrium, four polymorphisms in ApoA1 and four polymorphisms in the 5'-flanking regions and 3'-flanking regions from the JSNP database were determined in 1,880 subjects recruited from the Suita study, which represents the general population in Japan. Of the eight polymorphisms tested, the ApoA1 T84C polymorphism had the greatest effect on the levels of HDL-C ( P=0.0005, P(c)=0.0040 corrected by the Bonferroni method) and triglyceride ( P<0.0001, P(c)=0.0008). The ApoA1 MspI polymorphism was not associated with HDL-C or triglyceride levels. We confirmed that the ApoA1 T84C polymorphism was associated with the HDL-C level but not the triglyceride level in patients with MI ( n=637). Moreover, this polymorphism was associated with the incidence of MI in male subjects ( P=0.0326). A logistic analysis indicated that the frequency of MI in the CC genotype was lower than that in the CT+TT genotype ( P=0.0145, OR=0.4955, 95% CI: 0.2746-0.8525). The ApoA1 T84C polymorphism is an important marker for the HDL-C level and may be a new risk marker for MI in Japanese.

APOE polymorphism and lipid profile in three ethnic groups in the Singapore population

BACKGROUND

Serum lipid concentrations are modulated by environmental factors such as exercise, alcohol intake, smoking, obesity and dietary intake and genetic factors. Polymorphisms at the Apolipoprotein E (APOE) locus have consistently shown a significant association with total and LDL-cholesterol (LDL-C). However, their impact on HDL-cholesterol (HDL-C) may be population dependent. Having three major ethnic groups within a similar social environment allows us to study the role of genetics and their interactions with lifestyle factors on the serum lipid profile and coronary risk in Asians.

METHODS

This study included 1740 males (1146 Chinese, 327 Malays and 267 Asian Indians) and 1950 females (1329 Chinese, 360 Malays and 261 Asian Indians) with complete data on anthropometric indices, fasting lipids, smoking status, alcohol consumption, exercise frequency and genotype at the APOE locus.

RESULTS

Malays and Asian Indians were more obese compared with the Chinese. Smoking was uncommon in all females but Malay males had significantly higher prevalence of smokers. Malays had the highest LDL-C whilst Indians had the lowest HDL-C, The epsilon 3 allele was the most frequent allele in all three ethnic groups. Malays had the highest frequency of epsilon 4 (0.180 and 0.152) compared with Chinese (0.085 and 0.087) and Indians (0.108 and 0.075) in males and females, respectively. The epsilon 2 allele was the least common in Asian Indians. Total cholesterol (TC) and LDL-C was highest in epsilon 4 carriers and lowest in epsilon 2 carriers. The reverse was seen in HDL-C with the highest levels seen in epsilon 2 subjects. The association between ethnic group and HDL-C differed according to APOE genotype and gender. Asian Indians had the lowest HDL-C for each APOE genotype except in Asian Indian males with epsilon 2, where HDL-C concentrations were intermediate between Chinese and Malays.

CONCLUSION

Ethnic differences in lipid profile could be explained in part by the higher prevalence of epsilon 4 in the Malays. Ethnicity may influence the association between APOE genotypes and HDL-C. APOE genotype showed no correlation with HDL-C in Malay males whereas the association in Asian Indians was particularly marked. Further studies of interactions between genes and environmental factors will contribute to the understanding of differences of coronary risk amongst ethnic groups.

The effect of six polymorphisms in the Apolipoprotein B gene on parameters of lipid metabolism in a Danish population

Lipoproteins are vehicles for the distribution of plasma lipids and polymorphisms in the genes for apolipoproteins could influence the amount of lipid in plasma. We examined the effect of six single nucleotide polymorphisms in codons 71, 591, 2488, 2712, 3611, and 4154 of the apolipoprotein B gene on fasting levels of triglyceride, VLDL-, LDL-, HDL- and total cholesterol and on body mass index (BMI) in a cohort of 2656 Danes aged 40-70 years using a linear model correcting for the effects of gender, age, BMI, smoking, alcohol consumption and physical activity. The codon 2488 polymorphism was the most influential of the tested polymorphisms, significantly influencing triglyceride (P = 0.002), LDL-cholesterol (P < or = 0.0004), VLDL-cholesterol (P = 0.006) and total cholesterol (P = 0.0001). The codon 2712 polymorphism had an impact on triglyceride (P = 0.007) and VLDL-cholesterol (P = 0.001), while the codon 71 polymorphism influenced LDL- and total cholesterol (P = 0.04 and P = 0.02, respectively). An interaction between smoking and codon 591 (P = 0.03) and smoking and codon 3611 (P = 0.02) on BMI was observed, as well as modest interactions between codon 3611 and codons 2488 and 2712 on lipid parameters. All polymorphisms were in close linkage disequilibrium. The population was not in Hardy-Weinberg equilibrium in four of the six polymorphisms but the lack of equilibrium was restricted mainly to the 60-year olds.

Lipoprotein and apolipoprotein abnormalities in familial combined hyperlipidemia: a 20-year prospective study

In order to characterize the lipoprotein abnormalities in familial combined hyperlipidemia (FCHL) and to describe factors associated with the stability of the FCHL phenotype during 20-year follow-up, 287 individuals from 48 families with FCHL originally identified in the early 1970s (baseline) were studied. Hyperlipidemia was defined as lipid-lowering medication use, or > or =age- and sex-specific 90th percentile for triglycerides or cholesterol. Triglyceride, cholesterol and medical history data were obtained at baseline and 20-year follow-up. Additional follow-up measures included HDL-C, LDL-C, LDL particle size, lipoprotein(a), apolipoprotein (apo) A-I, apoB, and apoE polymorphism. Longitudinally, two-thirds of relatives were consistently normolipidemic or hyperlipidemic, and one third were discordant for hyperlipidemic status at baseline and 20-year follow-up. Individuals with hyperlipidemia at baseline and/or follow-up had higher apoB levels than those with consistently normal lipids (P<0.05), whereas small LDL size was associated with concurrent hyperlipidemia. Among individuals who were normolipidemic at baseline, the following variables were independently associated with development of hyperlipidemia over 20 years: older age at baseline, male sex, greater increase in BMI during follow-up, and apoE alleles epsilon 2 or epsilon 4. In conclusion, apoB is associated with hyperlipidemia and apoE polymorphism is associated with later onset of hyperlipidemia in FCHL.

A leucine(7)-to-proline(7) polymorphism in the signal peptide of neuropeptide Y was not identified in the Japanese population

OBJECTIVE

A Leu(7)-to-Pro(7) polymorphism exists in the signal peptide part of prepro-neuropeptide Y (NPY) and this polymorphism is associated with high serum cholesterol and LDL cholesterol levels in both Finnish and Dutch people. There was a significant difference in the allelic frequencies among populations with different genetic backgrounds. Therefore, the present study was designed to test whether Japanese people had the Leu(7)-to-Pro(7) polymorphism in the NPY signal peptide.

METHODS

A total of 102 healthy Japanese volunteers supplied blood samples, from which leucocyte DNA was isolated. Primer pairs for the polymerase chain reaction (PCR) were made according to Karvonen et al. Direct sequencing of the PCR product was carried out by the dye terminator method using a capillary electrophoresis sequencer.

RESULTS

All 102 young healthy Japanese subjects showed Leu(7)/Leu(7) but not Leu(7)/Pro(7) or Pro(7)/Pro(7) in the NPY signal peptide.

CONCLUSION

The incidence of the Leu(7)-to-Pro(7) polymorphism in the signal peptide of NPY was extremely low in Japanese people, suggesting that the polymorphism producing Pro(7) is not one of the genetic determinant factors affecting serum cholesterol levels in Japanese people.

Angiotensin converting enzyme genetic polymorphism is not associated with hypertension in a cross-sectional sample of a Japanese population: the Shibata Study

BACKGROUND

The studies on the association of deletion/ insertion (D/I) polymorphism of angiotensin converting enzyme (ACE) gene with blood pressure and hypertension reported contradictory results. Because there was no population-based study in Japan, we examine the hypothesized association in a cross-sectional sample of a Japanese cohort.

METHODS AND RESULTS

The blood pressure of 464 men and 876 women aged 40-80 years was measured, and their DNA was analyzed for ACE D/I genotypes. The prevalence of the D allele was 38.7 and 39.2% in men and women, respectively (overall 39%). There was a tendency for higher covariate (age, body mass index, albuminuria, hematocrit, alcohol consumption, smoking, diabetes mellitus, ischemic heart disease and antihypertensive medication) adjusted mean levels of diastolic blood pressure for the DD genotype in men but not in women. However, this tendency disappeared after dichotomization of blood pressure into diagnostic categories (normotension and hypertension). Results did not differ when the subjects were divided into two age groups (< or = 59 and > or = 60 years). Covariate-adjusted odds ratios for hypertension for presence of the D allele were close to the null value of one. ACE genetic variation accounted for only 0.1 and 0.7% of the inter-individual variation in systolic and diastolic blood pressure in men. These estimates were 0.2 and 0.1%, respectively, in women.

CONCLUSION

Although there is a tendency of higher diastolic blood pressure in men with DD genotypes, there is no convincing evidence that ACE genotypes are associated with hypertension in this Japanese population.

Effects of the ApoE polymorphism on plasma lipoproteins in Mexican Americans

PURPOSE

To evaluate the impact of apolipoprotein E (apoE) genotypes on lipoprotein measurements relative to that of other known cardiovascular risk factors in participants of a large population-based family study.

METHODS

We measured concentrations of apoE, the major constituents of HDL (cholesterol, apoAI), LDL-C (cholesterol and apoB), and fraction of apoE in lipoprotein size classes in 859 participants of the San Antonio Family Heart Study, and then tested the association between the three common apoE genotypes (epsilon2epsilon3, epsilon3epsilon3, and epsilon3epsilon4) and lipoprotein traits using the measured genotype approach to account for residual familial correlations.

RESULTS

Allele frequencies in this population for epsilon2, epsilon3, and epsilon4 were 3.5%, 89.6%, and 6.9%, respectively. As expected, adjusted apoE concentrations were highest in those with epsilon2epsilon3, intermediate in those with epsilon3epsilon3, and lowest in those with epsilon3epsilon4. The concentrations of total cholesterol, LDL-C and apoB were lowest in those with epsilon2epsilon3, intermediate in those with epsilon3epsilon3, and highest in those with epsilon3epsilon4. There was no significant effect of apoE genotypes on triglycerides, HDL-C, or apoAI levels. Compared to subjects with epsilon3epsilon4, subjects with epsilon2epsilon3 had relatively less apoE in LDL and HDL(1), and relatively more in HDL(2) and HDL(3) size fractions. The effect of apoE genotypes was significantly greater on apoB in women than in men. ApoE genotypes accounted for 4.5%, 12.3%, and 4.7% of the total genetic variation in apoB, apoE, and LDL-C, respectively.

CONCLUSION

ApoE genotypes account for a modest, albeit significant, proportion of phenotypic variation in concentrations of LDL-C, apoB, and apoE, and distributions of apoE among lipoproteins in this population; these genotypes have a greater effect on apoB levels in women than in men.

Association of the apolipoprotein B gene polymorphisms with cholesterol levels and response to fluvastatin in Brazilian individuals with high risk for coronary heart disease

The influence of genetic polymorphism of the apolipoprotein B on lipid metabolism and coronary heart disease (CHD) risk has been demonstrated in different populations, but few studies have shown the contribution of this risk factor in individuals from Brazil. The Ins/del, Xbal and EcoRI polymorphisms of apo B were evaluated in 93 controls and in 104 Caucasian individuals presenting with a high risk lipid profile (HR1) for CHD; 54 of these subjects (HR2) were treated with fluvastatin during 16 weeks. DNA polymorphisms of the apo B gene were analyzed by polymerase chain reaction-restriction fragment length polymorphism. The X(-)X(-) genotype for Xbal polymorphism was associated with higher serum concentrations of total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) (p<0.01) in women of the HR1 group. The Ins/del and EcoRI polymorphisms were not associated with variation of lipid profile. After treatment with fluvastatin, TC and LDL-C levels of HR2 individuals were reduced by 23% and 30%, respectively. Individuals with II genotype had significantly greater reduction (34%) of LDL-C than those with ID/DD genotypes (27%). These results indicate that the Xbal polymorphism is associated with variation of serum TC and LDL-C levels in Brazilian women with lipid profile of risk for CHD and the Ins/del polymorphism is associated with the therapeutic response to fluvastatin.

Association of apolipoprotein E polymorphism with plasma lipids and Alzheimer's disease in a Southern Brazilian population

Apolipoprotein E (protein: apo E; gene: APOE) plays an important role in the multifactorial etiology of both Alzheimer's disease (AD) and lipid level concentrations. The polymerase chain reaction (PCR) was used to investigate the APOE gene polymorphism in 446 unrelated Caucasians, among them 23 AD patients, and 100 Afro-Brazilians living in Porto Alegre, Brazil. The frequencies of the APOE*2, APOE*3 and APOE*4 alleles were 0.075, 0.810 and 0.115 in Caucasians and 0.075, 0.700 and 0.225 in Afro-Brazilians, respectively (chi2 = 8.72, P = 0.013). A highly significant association was observed between the APOE*4 allele and AD in this population-based sample. The APOE*4 frequency in AD patients (39%) was about four times higher than in the general Caucasian population (11.5%). The influence of each of the three common APOE alleles on lipid traits was evaluated by the use of the average excess statistic. The E*2 allele is associated with lower levels of triglycerides and of total and non-HDL cholesterol in both men and women. Conversely, the E*4 allele is associated with higher levels of these traits in women only. The effect of APOE alleles was of greater magnitude in women.

Relationship between the apolipoprotein E and angiotensin-converting enzyme genotypes and LDL particle size in Japanese subjects

We investigated whether the apolipoprotein E (apoE) and the angiotensin-converting enzyme (ACE) genotypes contribute to the variance in low-density lipoprotein (LDL) particle size in Japanese subjects (n = 136; M/F= 106/30). ACE polymorphism was associated with neither LDL size nor individual lipid levels. In contrast, the subjects with the epsilon2 allele of the apoE genotype had significantly lower levels of total cholesterol (P = 0.002) and LDL cholesterol (P = 0.004) compared with those without the epsilon2 allele. The subjects with the epsilon4 allele had a significantly smaller LDL particle size than those without the epsilon4 allele (P = 0.012). Separate analyses of the male subjects showed similar associations. A stepwise regression analysis revealed the epsilon4 allele to be an independent contributing variable that could affect LDL particle size. Our results suggest that the apoE genotype is associated with the development of atherosclerotic disease, since the epsilon2 and epsilon4 alleles relate to a decrease in LDL cholesterol levels and a decrease in LDL particle size, respectively.

Association of the insertion/deletion gene polymorphism of the apolipoprotein B signal peptide with myocardial infarction

The Del allele of the apolipoprotein B (apoB) signal peptide (SP) insertion/deletion (Ins/Del) polymorphism has been shown to be associated with elevated plasma levels of apoB, cholesterol and low density lipoprotein. It was the aim of the present study to analyse the relation of this gene variation to the risk of coronary artery disease (CAD) and of myocardial infarction (MI) in a population of 2259 male Caucasians, whose coronary anatomy was defined by means of coronary angiography. ApoB SP DelDel genotypes had significantly higher apoB plasma concentrations than InsIns homozygotes (P = 0.0001) and InsDel heterozygotes (P = 0.002); however, the apoB plasma levels of InsIns and InsDel genotypes were essentially the same (P = 0.54). Similar observations were made with respect to ApoB SP genotype-dependent cholesterol plasma concentrations. Since the apoB plasma level was not only associated with the apoB SP Ins/Del gene variation but also to the extent of coronary artery disease (P <0.0001), individuals with an InsIns genotype and without CAD had the lowest and subjects with a DelDel genotype and triple vessel disease the highest apoB plasma levels (P <0.0001). An association of the apoB SP Ins/Del gene variation with CAD was not detected, neither in the total population nor in low risk groups. In contrast, the gene variation was associated with MI (P <0.05). An Odds ratio of 1.18 (95% CI, 1.01-1.39) associated with the Del allele was detected in the total sample (P <0.02). In a subpopulation of individuals with low plasma triglyceride levels ( <154 mg/dl; mean value) and an DD genotype of the angiotensin I-converting enzyme insertion/deletion gene polymorphism an Odds ratio of 2.01 (1.42-3.05) was calculated (P <0.001). The present study presents evidence for a statistically significant difference in the development of MI between genotype classes of the apoB SP Ins/Del gene polymorphism.