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

Macronutrient intake modulates impact of EcoRI polymorphism of ApoB gene on lipid profile and inflammatory markers in patients with type 2 diabetes

We sought to examine whether dietary intakes may affect the relationship between ApoB EcoRI and lipid profile, as well as serum inflammatory markers, in patients with type 2 diabetes (T2DM). This current study consisted of 648 diabetic patients. Dietary intake was calculated by a food frequency questionnaire. Biochemical markers (high-density lipoprotein (HDL), total cholesterol (TC), LDL, TG, CRP, IL-18, PGF2α) were measured based on standard protocols. Genotyping of the Apo-B polymorphisms (rs1042031) was conducted by the PCR–RFLP method. The gene-diet interactions were evaluated using GLMs. In comparison to GG homozygotes, A-allele carriers with above the median -CHO intake (≥ 54 percent of total energy) had considerably greater TC and PGF2a concentrations. Furthermore, as compared to GG homozygotes, A-allele carriers with above the median protein intake (≥ 14 percent of total energy) had higher serum levels of TG (P = 0.001), CRP (P = 0.02), TG/HDL (P = 0.005), and LDL/HDL (P = 0.04) ratios. Moreover, A-allele carriers with above the median total fat intake (≥ 35 percent of total calories) had significantly higher TC level (P = 0.04) and LDL/HDL (P = 0.04) ratios compared to GG homozygotes. Furthermore, when compared to GG homozygotes, A-allele carriers who consumed above the median cholesterol (> 196 mg) had greater TG (P = 0.04), TG/HDL (P = 0.01) ratio, and IL-18 (P = 0.02). Furthermore, diabetic patients with the GA, AA genotype who consume above the median cholesterol had lower ghrelin levels (P = 0.01). In terms of LDL/HDL ratio, ApoB EcoRI and dietary intakes of specific fatty acids (≥ 9 percent for SFA and ≥ 12 percent for MUFA) had significant interaction. LDL/HDL ratio is greater in A-allele carriers with above the median SFA intake (P = 0.04), also when they consumed above the median MUFA this association was inverse (P = 0.04). Our study showed that plasma lipid levels in participants carrying the (AA or AG) genotype were found to be more responsive to increasing the percentage of energy derived from dietary fat, CHO, protein, SFA, and cholesterol consumption. Therefore, patients with a higher genetic susceptibility (AA or AG) seemed to have greater metabolic markers with a higher percentage of macronutrient consumption. Also, ApoB EcoRI correlations with metabolic markers might be attenuated with above the median MUFA consumption.

Polymorphisms in Genes of Lipid Metabolism Are Associated with Type 2 Diabetes Mellitus and Periodontitis, as Comorbidities, and with the Subjects' Periodontal, Glycemic, and Lipid Profiles

BACKGROUND

Type 2 diabetes mellitus (T2DM) and periodontitis (P) commonly occur as comorbidities, but the commonalities in the genetic makeup of affected individuals is largely unknown. Since dyslipidemia is a frequent condition in these individuals, we investigate the association of genomic variations in genes involved in lipid metabolism with periodontal, glycemic, lipid profiles, and the association with periodontitis and T2DM (as comorbidities).

METHODS

Based on clinical periodontal examination and biochemical evaluation, 893 subjects were divided into T2DM+P (T2DM subjects also affected by periodontitis, n = 205), periodontitis (n = 345), and healthy (n = 343). Fourteen single-nucleotide polymorphisms (SNPs) were investigated: LDLR gene (rs5925 and rs688), APOB (rs676210, rs1042031, and rs693), ABCC8 (rs6544718 and 6544713), LPL (rs28524, rs3735964, and rs1370225), HNF1A (rs2650000), APOE (rs429358 and rs7412), and HNF4A (rs1800961). Multiple linear and logistic regressions (adjusted for covariates) were made for all populations and stratified by sex and smoking habits.

RESULTS

Individuals carrying APOB-rs1042031-CT (mainly women and never smokers) had a lower risk of developing periodontitis and T2DM (T2DM+P); altogether, this genotype was related with healthier glycemic, lipid, and periodontal parameters. Significant disease-phenotype associations with gene-sex interaction were also found for carriers of APOB-rs1676210-AG, HNF4A-rs1800961-CT, ABCC8-rs6544718-CT, LPL-rs13702-CC, and LPL-rs285-CT.

CONCLUSIONS

Polymorphisms in lipid metabolism genes are associated with susceptibility to T2DM-periodontitis comorbidities, demonstrating gene-sex interaction. The APOB-rs1042031 was the most relevant gene marker related to glucose and lipid metabolism profiles, as well as with obesity and periodontitis.

Molecular analysis of APOB, SAR1B, ANGPTL3, and MTTP in patients with primary hypocholesterolemia in a clinical laboratory setting: Evidence supporting polygenicity in mutation-negative patients

BACKGROUND AND AIMS

Primary hypobetalipoproteinemia is generally considered a heterogenic group of monogenic, inherited lipoprotein disorders characterized by low concentrations of LDL cholesterol and apolipoprotein B in plasma. Lipoprotein disorders include abetalipoproteinemia, familial hypobetalipoproteinemia, chylomicron retention disease, and familial combined hypolipidemia. Our aim was to review and analyze the results of the molecular analysis of hypolipidemic patients studied in our laboratory over the last 15 years.

METHODS

The study included 44 patients with clinical and biochemical data. Genomic studies were performed and genetic variants were characterized by bioinformatics analysis. A weighted LDL cholesterol gene score was calculated to evaluate common variants associated with impaired lipid concentrations and their distribution among patients.

RESULTS

Twenty-three patients were genetically confirmed as affected by primary hypobetalipoproteinemia. In this group of patients, the most prevalent mutated genes were APOB (in 17 patients, with eight novel mutations identified), SAR1B (in 3 patients, with one novel mutation identified), ANGPTL3 (in 2 patients), and MTTP (in 1 patient). The other 21 patients could not be genetically diagnosed with hypobetalipoproteinemia despite presenting suggestive clinical and biochemical features. In these patients, two APOB genetic variants associated with lower LDL cholesterol were more frequent than in controls. Moreover, the LDL cholesterol gene score, calculated with 11 SNPs, was significantly lower in mutation-negative patients.

CONCLUSIONS

Around half of the patients could be genetically diagnosed. The results suggest that, in at least some of the patients without an identified mutation, primary hypobetalipoproteinemia may have a polygenic origin.

Nutrigenetic variants and cardio-metabolic risk in women with or without gestational diabetes

AIM

Gestational diabetes mellitus (GDM) is the most frequent metabolic disorder in pregnancy and it can be considered a silent risk associated to T2DM and CVD later in life. The aim of this study was to investigate the association of clinical parameters with nine single nucleotide polymorphisms (SNPs) involved with nutrients and metabolism in women with or without GDM in order to identify potential routine clinical markers for early prevention.

METHODS

Nine gene variants associated with nutrients and metabolism, namely PPARG2 rs1801282 (C > G); PPARGC1A rs8192678 (C > T); TCF7L2 rs7903146 (C > T); LDLR rs2228671 (C > T); MTHFR rs1801133 (C > T); APOA5 rs662799 (T > C); GCKR rs1260326 (C > T); FTO rs9939609 (T > A); MC4R rs17782313 (T > C) were genotyped in 104 GDM cases and 124 controls using High Resolution Melting (HRM) analysis.

RESULTS

The genetic variant rs7903146 (C > T) in TCF7L2 gene showed a strong association with GDM risk (OR: 2.56; 95% CI: [1.24-5.29]). Moreover, a significant correlation was observed between lipid parameters and polymorphisms in other genes, namely PPARG2 [p = 0,03], APOA5 [p = 0,02], MC4R [p = 0,03], LDLR [p = 0,04] and FTO [p = 0,03]. In addition, rs17782313 variant, mapped close to MC4R gene, was associated to BMI in pre-pregnancy [p = 0,02] and at the end of pregnancy [p = 0,03] in GDM group.

CONCLUSION

In our study, we found significant associations between routine clinical parameters and some gene variants connected with nutrients and metabolism in women with GDM. These results can provide useful information to develop effective tools and possible personalized intervention strategies in a timely manner.

Association analysis of APO gene polymorphisms with ischemic stroke risk: a case-control study in a Chinese Han population

This study aimed to assess the association of APO gene polymorphisms and ischemic stroke risk in a Chinese Han population. In this case-control study, we genotyped 14 single nucleotide polymorphisms (SNPs) in 3 APO genes in 488 cases and 503 controls using Sequenom Mass-ARRAY technology and evaluated their association with ischemic stroke using the χ2 and genetic model analysis. In the allelic model analysis, we determined three SNPs were significantly associated with ischemic stroke: rs693 with a p value of 0.042 (OR = 1.406; 95%CI = 1.011-1.956), rs651821 with a p value of 0.007 (OR = 0.760; 95%CI = 0.622-0.929) and rs662799 with a p value of 0.006 (OR = 0.755; 95%CI = 0.618-0.923). In the genetic model analysis, we found the minor allele “A” of rs693 was associated with an increased ischemic stroke risk in the additive model and dominant model. The minor allele “C” of rs651821 was associated with a decreased ischemic stroke risk in the additive model. The minor allele “G” of rs662799 was associated with a decreased ischemic stroke risk in the additive model. Additionally, strong linkage was found in 3 blocks constituted by rs1042034, rs676210, rs693, rs673548 in APOB; rs3791981, rs679899 in APOB; and rs651821, rs662799, rs17120035 in APOA5. Our data suggested that gene polymorphisms in the APO genes may exert influences ischemic stroke susceptibility in a Chinese Han population.

Human Nutrition and Genetic Variation

Human genetic variation is a determinant of nutrient efficacy and of tolerances and intolerances and has the potential to influence nutrient intake values (NIVs). Knowledge derived from the comprehensive identification of human genetic variation offers the potential to predict the physiological and pathological consequences of individual genetic differences and prevent and/or manage adverse outcomes through diet. Nutrients and genomes interact reciprocally; genomes confer differences in nutrient utilization, whereas nutrients effectively modify genome expression, stability, and viability. Understanding the interactions that occur among human genes, including all genetic variants thereof, and environmental exposures is enabling the development of genotype-specific nutritional regimens that prevent disease and promote wellness for individuals and populations throughout the life cycle. Genomic technologies may provide new criteria for establishing NIVs. The impact of a gene variant on NIVs will be dependent on its penetrance and prevalence within a population. Recent experiences indicate that few gene variants are anticipated to be sufficiently penetrant to affect average requirement (AR) values to a greater degree than environmental factors. If highly penetrant gene variants are identified that affect nutrient requirements, the prevalence of the variant in that country or region will determine the feasibility and necessity of deriving more than one AR or upper limit (UL) for affected genetic subgroups.

Relationship Between Two Common Lipoprotein Lipase Variants and the Metabolic Syndrome and Its Individual Components

BACKGROUND

Common lipoprotein lipase (LPL) variants are important determinants of triglycerides (TG) and high-density lipoprotein (HDL) cholesterol (C) concentrations. High TG/low HDL-C tend to cluster with hypertension, glucose intolerance, and abdominal obesity and comprise the metabolic syndrome (MetS). The role of LPL variants as a cause of MetS is unclear. This study investigated the relationship between two common LPL variants and the presence of MetS and its individual components.

METHODS

Cross-sectional study, including 2348 Danish women (50.7%) and men, age 41-72 years, without known cardiovascular disease. Carrier status for the two common LPL variants: 447Ter (low TG/high HDL-C) and 291Ser (high TG/low HDL-C) was determined. The prevalence of MetS according to the National Cholesterol Education Program criteria was 16.6%.

RESULTS

Of the 2348 participants, 19.8% had the 447Ter variant and 4.9% had the 291Ser variant. Compared with the reference variant, the prevalence of MetS was lower in carriers of the 447Ter variant (11.2% vs. 17.9%, P < 0.001) but with no difference in carriers of the 291Ser variant (18.4% vs. 16.5%, P = 0.59). Adjusted for age, sex, smoking, physical activity, alcohol consumption, and highest sex-specific insulin quartile, the relative risk of MetS was 0.63 (95% confidence interval [CI] 0.45-0.89, P < 0.01) for carriers of the 447Ter variant and 1.20 (95% CI 0.70-2.03, P > 0.05) for carriers of the 291Ser variant. Both LPL variants were associated with high TG/low HDL-C (P < 0.01), but not with the MetS components waist circumference, hypertension, and glucose intolerance (P > 0.05).

CONCLUSION

The two common LPL variants were associated with MetS through their effect on high TG/low HDL-C.

Association between the APOB XbaI and EcoRI polymorphisms and lipids in Chinese: a meta-analysis

Background

No previous meta-analysis was to report the association between the apolipoprotein B (APOB) XbaI and EcoRI polymorphisms and serum lipids in Chinese. We performed the study to investigate their potentially association.

Methods and Results

Studies in English and Chinese were found via a systematic search of Pubmed, Embase, CNKI and Wanfang databases. The dominant genetic model and random-effects model were used to pool data from individual studies. As a result, a total of 30 articles with 5611 subjects for XbaI and 2653 subjects for EcoRI were included in the current study. For the XbaI polymorphism, overall, subjects carrying X+ allele were significantly associated with higher TC,TG and LDL compared with X-X- genotype (Pvalue =0.0006, OR (95 %) = -0.55 (-0.86,-0.23); Pvalue = 0.0004, OR (95 %) = -0.30 (-0.47,-0.14); (Pvalue = 0.05, OR (95 %) = -0.23(-0.46,-0.00), respectively). Similar results were observed in the subgroups of Han, healthy individuals (HT), coronary heart disease (CHD), cerebral infarction (CI), and cholelithiasis. For HDL, positive association between X+ allele with Lower lipid value was found in CHD and CI subgroups. For EcoRI polymorphism, overall, the E- allele carriers were found to be obviously linked with elevated LDL and lower HDL compared with E + E+ genotype (Pvalue = 0.02,OR (95 %) = -0.27 (-0.49,-0.05); Pvalue = 0.01, OR (95 %) = 0.17 (0.03, 0.30), respectively). TC was significantly high in subjects carrying E- allele in the subgroup of hyperlipidemia. No evidence of publication bias was observed.

Conclusions

The two genetic variants of APOB may be associated with serum lipids in Chinese.

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.

C-reactive protein, insulin resistance and risk of cardiovascular disease: a population-based study

BACKGROUND

C-reactive protein (CRP), a marker of inflammation, and insulin resistance (IR), a metabolic disorder, are closely related. CRP and IR have both been identified as significant risk factors of cardiovascular disease (CVD) after adjustment for conventional CVD risk factors. It is not clear whether CRP predicts CVD independent of IR.

DESIGN

Prospective population-based study.

METHODS

Two thousand three hundred and fifty-seven Danish men and women, recruited from the general population, aged 41-72 years, without major CVD at baseline were studied. Traditional and new risk factors were recorded at baseline. CRP was determined by a high-sensitivity assay, and IR was determined by the homoeostasis model assessment (HOMA-IR) method.

RESULTS

Over a median follow-up of 9.4 years, the incidence of the prespecified CV event, defined as the composite event of CV death, nonfatal ischaemic heart disease and nonfatal stroke, amounted to 222 cases. In Cox proportional-hazard models, adjusted for age, sex, smoking habit, total cholesterol, waist circumference, levels of triglycerides and high-density lipoprotein-cholesterol, systolic and diastolic blood pressures, physical activity and HOMA-IR, the hazard ratio (95% confidence interval) of a CV event was 1.33 (1.14-1.55; P<0.001) per standard deviation increase in log-transformed CRP level. In the same model, the hazard ratio of a CV event was 1.11 (1.02-1.21; P<0.05) per standard deviation increase in HOMA-IR level.

CONCLUSION

In a general Danish population free of major CVD at baseline, both CRP and IR were significantly related to risk of CVD.

Common and rare alleles in apolipoprotein B contribute to plasma levels of low-density lipoprotein cholesterol in the general population

CONTEXT

We have previously shown that rare mutations in the apolipoprotein B gene (APOB) may result in not only severe hypercholesterolemia and ischemic heart disease but also hypocholesterolemia. Despite this, common single-nucleotide polymorphisms (SNPs) in APOB have not convincingly been demonstrated to affect low-density lipoprotein (LDL) cholesterol levels.

OBJECTIVE

We tested the hypothesis that nonsynonymous SNPs in three important functional domains of APOB and APOB tag SNPs predict levels of LDL cholesterol and apolipoprotein B and risk of ischemic heart disease.

DESIGN

This was a prospective study with 25 yr 100% follow up, The Copenhagen City Heart Study.

SETTING

The study was conducted in the Danish general population.

PARTICIPANTS

Participants included 9185 women and men aged 20-80+ yr.

MAIN OUTCOME MEASURES

Levels of LDL cholesterol and apolipoprotein B and risk of ischemic heart disease and myocardial infarction were measured. The hypothesis was formulated before genotyping.

RESULTS

We genotyped 9185 individuals for APOB T71I (minor allele frequency: 0.33), Ivs4+171c>a (0.14), A591V (0.47), Ivs18+379a>c (0.30), Ivs18+1708g>t (0.45), T2488Tc>t (0.48), P2712L (0.21), R3611Q (0.09), E4154K (0.17), and N4311S (0.21). SNPs were associated with increases (T71I, Ivs181708g>t, T2488Tc>t, R3611) or decreases (Ivs4+171c>a, A591V, Ivs18+379a>c, P2712L, E4154, N4311S) in LDL cholesterol from -4.7 to +8.2% (-0.28 to 0.30 mmol/liter; P<or=0.002), and corresponding effects on cholesterol and apolipoprotein B levels. However, as predicted from the magnitude of the observed LDL cholesterol effects, none of these SNPs predicted risk of ischemic heart disease prospectively in the general population, in a case-control study, or as haplotypes.

CONCLUSIONS

Multiple common and rare alleles in APOB contribute to plasma levels of LDL cholesterol in the general population, although the effects of common alleles and haplotypes are modest.

Polymorphisms in apolipoprotein B and risk of ischemic stroke

CONTEXT

Apolipoprotein B levels associate with risk of ischemic stroke. APOB polymorphisms may influence levels of apolipoprotein B and low-density lipoprotein (LDL), but whether they associate with risk of ischemic stroke is unknown.

OBJECTIVE

We tested the hypothesis that the APOB T71I, A591V, P2712L, R3611Q, E4154K, and N4311S polymorphisms associate with risk of ischemic stroke in the general population and performed in vivo human LDL turnover studies of E4154K heterozygotes vs. K4154K homozygotes.

DESIGN

This was a prospective study (the Copenhagen City Heart Study) with 23-yr, 100% complete follow-up.

SETTING

The study was conducted with a Danish general population.

PARTICIPANTS

A total of 9157 women and men aged 20-80+ yr participated in the study.

MAIN OUTCOME MEASURES

Risk of ischemic cerebrovascular disease and ischemic stroke, apolipoprotein B and LDL levels, and LDL fractional catabolic rate were measured. The hypothesis was formulated before genotyping.

RESULTS

APOB K4154K homozygotes had an age-adjusted hazard ratio of 0.4 (95% confidence interval 0.2-0.9) for ischemic cerebrovascular disease and 0.2 (0.1-0.7) for ischemic stroke relative to E4154E homozygotes. Corresponding multifactorially adjusted hazard ratios were 0.5 (0.2-1.0) and 0.2 (0.1-0.8). Furthermore, E4154K heterozygotes and K4154K homozygotes had lower levels of apolipoprotein B and LDL cholesterol, compared with E4154E homozygotes. Finally, E4154K heterozygotes had an increased fractional catabolic rate of LDL relative to E4154E homozygotes. None of the other polymorphisms studied influenced risk of ischemic stroke.

CONCLUSIONS

APOB K4154K homozygosity predicts a 3- to 5-fold reduction in risk of ischemic cerebrovascular disease and ischemic stroke. This may be explained by lower plasma levels of apolipoprotein B and LDL cholesterol caused by an increased catabolism of LDL particles, although another yet-unknown mechanism is also possible.

Insulin resistance, the metabolic syndrome, and risk of incident cardiovascular disease: a population-based study

OBJECTIVES

The goal was to clarify if insulin resistance (IR) would predict cardiovascular disease (CVD) independent of the metabolic syndrome (MetSyn).

BACKGROUND

Although the cause of MetSyn is not well defined, IR has been proposed to be an important cause. Only a small number of population-based studies have sought to clarify if IR predicts CVD independent of MetSyn.

METHODS

This was a prospective Danish population-based study of 2,493 men and women, age 41 to 72 years, without major CVD at baseline. We defined MetSyn according to both the International Diabetes Foundation (IDF) and the National Cholesterol Education Program (NCEP) criteria, and we quantified IR by the homeostasis model assessment (HOMA-IR). Prevalence of MetSyn was 21% according to IDF criteria and 16% according to NCEP criteria. Accordingly, we defined IDF-HOMA-IR as belonging to the highest 21% of the HOMA-IR distribution, and NCEP-HOMA-IR as belonging to the highest 16% of the HOMA-IR distribution.

RESULTS

Over a median follow-up of 9.4 years, the incidence of CV end points (CV death, nonfatal ischemic heart disease, and nonfatal stroke) amounted to 233 cases. In proportional hazard models, adjusting for age, gender, smoking, and low-density lipoprotein cholesterol, and with IDF-HOMA-IR and IDF-MetSyn included in the same model, the relative risk of an end point was 1.67 (95% confidence interval [CI] 1.22 to 2.29) for IDF-HOMA-IR and 1.16 (95% CI 0.84 to 1.60) for IDF-MetSyn. The corresponding figures for NCEP-HOMA-IR and NCEP-MetSyn included in the same model were 1.49 (95% CI 1.07 to 2.07) and 1.56 (95% CI 1.12 to 2.17).

CONCLUSIONS

In this Danish study, both HOMA-IR and NCEP-MetSyn were independent predictors of incident CVD.

Metabolic syndrome, low-density lipoprotein cholesterol, and risk of cardiovascular disease: A population-based study

We sought to examine the relative contribution to cardiovascular risk of the metabolic syndrome (MS) compared with that of a high LDL cholesterol level in a population-based study of 2493 men and women, age 41-72 years, without major cardiovascular diseases at baseline. MS was defined according to the National Cholesterol Education Program criteria. The study population was subdivided into four groups on the basis of presence (prevalence: 15%) or absence of MS (85%) and presence (15%) or absence of high LDL cholesterol (85%) defined as a level >5.02 mmol/L or </=5.02 mmol/L. After 9.5 years, 233 had a cardiovascular endpoint (cardiovascular death, ischemic heart disease, and stroke). In proportional-hazard models, adjusting for age, sex, and smoking, and with subjects without MS and LDL cholesterol </=5.02 mmol/L as reference (73%), the relative risk of an endpoint (95% CI) was 1.49 (1.04-2.13) in participants without MS and LDL cholesterol >5.02 mmol/L (12%), 1.80 (1.26-2.57) in subjects with MS and LDL cholesterol </=5.02 mmol/L (12%) and 3.21 (1.99-5.17) in participants with both MS and LDL cholesterol >5.02 mmol/L (3%). In a general population, MS was associated with a cardiovascular risk comparable with that of a high LDL cholesterol level.

Single nucleotide polymorphisms predict the change in left ventricular mass in response to antihypertensive treatment

BACKGROUND

Our aim was to determine whether the change in left ventricular (LV) mass in response to antihypertensive treatment could be predicted by multivariate analysis of single nucleotide polymorphisms (SNPs) in candidate genes reflecting pathways likely to be involved in blood pressure control.

METHODS

Patients with mild to moderate primary hypertension and LV hypertrophy were randomized in a double-blind fashion to treatment with either the angiotensin II type 1 receptor antagonist irbesartan (n = 48) or the beta1 adrenoreceptor blocker atenolol (n = 49). A microarray-based minisequencing system was used for genotyping 74 SNPs in 25 genes. These genotypes were related to the change in LV mass index by echocardiography, after 12 weeks treatment as monotherapy, using stepwise multiple regression analysis.

RESULTS

The blood pressure reductions were similar and significant in both treatment groups. Two SNPs in two separate genes (the angiotensinogen T1198C polymorphism, corresponding to the M235T variant and the apolipoprotein B G10108A polymorphism) for those treated with irbesartan, and the adrenoreceptor alpha2A A1817G for those treated with atenolol, significantly predicted the change in LV mass. The predictive power of these SNPs was independent of the degree of blood pressure reduction.

CONCLUSION

SNPs in the angiotensinogen, apolipoprotein B, and the alpha2 adrenoreceptor gene predicted the change in LV mass during antihypertensive therapy. These results illustrate the potential of using microarray-based technology for SNP genotyping in predicting individual drug responses.

Exploration of multilocus effects in a highly polymorphic gene, the apolipoprotein (APOB) gene, in relation to plasma apoB levels

A detailed exploration of all the polymorphisms in candidate genes is required to better characterize the relationship between gene variability and complex traits. We propose a novel strategy for investigating the association between a highly polymorphic gene and a phenotype, by combining a multilocus genotype analysis and an haplotype analysis. For the multilocus genotype analysis, a data mining tool--termed DICE (Detection of Informative Combined Effects)--was developed to identify the best subset of polymorphisms that are associated--individually or in combination--with the phenotype. For the haplotype analysis, we used our recently developed method of haplotype-phenotype association to determine the most informative and parsimonious haplotype model fitting the data. We illustrate this strategy by investigating the association between twelve polymorphisms of the APOB gene and plasma apoB levels in 1442 European subjects. After exploring all main effects and interactions between polymorphisms, DICE identified the N4311S polymorphism as the most informative polymorphism in relation to apoB levels. Haplotype analysis led to the same conclusion. Additionally, DICE identified the E4154K (EcoRI) and the T2488T (XbaI) polymorphisms as potentially interesting. This selection was not modified by inclusion of the common APOE polymorphism in the analysis.

Relation between XbA1 apolipoprotein B gene polymorphism and cardiovascular risk in a type 2 diabetic cohort

AIM

To evaluate in a prospective study the association of XbA1 apolipoprotein B (apoB) gene polymorphism with lipid parameters and cardiovascular (CV) events in a type 2 diabetic cohort.

METHODS AND RESULTS

A cohort of 212 type 2 diabetic patients, free of any cardiovascular complication, was studied. Cardiovascular events were registered for all the patients for 5 years. XbA1 apolipoprotein B gene polymorphism was analysed by PCR-RFLP method. A mild increase in HbA1c was found in X+X+ carriers (P = 0.014). Despite this lower glycemic control, there were no differences between genotype subgroups for lipid parameters except for apoB, significantly higher in X+X+ than in X-X- subjects. In univariate analysis, the cardiovascular events rate was higher in X-X- but did not reach statistical significance (P =0.07). In stepwise multivariate regression analysis, cardiovascular events risk was significantly higher in X- carriers (P = 0.014) and also in smokers, microalbuminuric and older patients.

CONCLUSIONS

We report for the first time in a prospective study the association of XbA1 apolipoprotein B gene polymorphism and cardiovascular events in a diabetic population. The mechanism underlying the excess of cardiovascular risk in X- carriers, despite a better metabolic profile, is likely to involve a linkage disequilibrium between apolipoprotein B gene locus and another gene locus related to cardiovascular risk.

Genetic effect of two polymorphisms in the apolipoprotein A5 gene and apolipoprotein C3 gene on serum lipids and lipoproteins levels in a Chinese population

Two polymorphisms, apolipoprotein A5 (APOA5) -1131T>C and apolipoprotein C3 (APOC3) -482C>T, were examined in a healthy Chinese group. Analysis of covariance (ancova) showed that both -1131T>C and -482C>T minor alleles were associated with triglyceride (TG)-raising effects (p < 0.001 and p = 0.012, respectively) after adjustment of sex, age, and body mass index (BMI). Moreover, -1131T>C minor alleles were also found to be associated with total cholesterol (TC)-raising effects (p = 0.045). However, the relationship between -482C>T minor alleles and TC-raising effects was not observed after adjustment of sex, age, and BMI. By contrast, significant inverse associations were noted between minor alleles (-1131T>C and -482C>T) and high-density lipoprotein cholesterol (HDL-C) concentrations (p = 0.021 and p = 0.021, respectively). Linear regression analysis showed that the effects of -1131T>C and -482C>T polymorphisms on TG and HDL-C (0.001 and 0.008; 0.041 and 0.005, respectively) are independent and additive and that -1131T>C can seriously affect the levels of TG (0.001 vs 0.008). The additive effect of the two polymorphisms was confirmed further by haplotype analysis. Our results strongly support that the two single nucleotide polymorphisms, -1131T>C in APOA5 and -482C>T in APOC3, are related to the levels of serum TG and HDL-C and those of other several lipids and lipoproteins in the Chinese population.

Relation between insulin and aortic stiffness: a population-based study

Recent studies have suggested that a high pulse wave velocity (PWV), a measure of aortic stiffness, may be a stronger risk factor for cardiovascular disease (CVD) than a high blood pressure (BP). The relation between insulin, believed to play an important role in the development and clinical course of high BP, and PWV is not yet clear. Therefore, we decided to examine the relationship between insulin and PWV in a large population-based study. The study population consisted of a random sample of 1213 women and 1207 men (age range, 41-72 years) without a history of myocardial infarction or stroke. Fasting insulin was determined together with conventional risk factors for CVD. PWV was recorded transcutaneously by a mechanical electrical principle with one transducer positioned over the left common carotid artery, and another over the left femoral artery. In univariate analysis, insulin was highly significantly related to PWV (standardized regression coefficient: 0.0669+/-0.0051; P<0.001). In multivariate analysis, controlling for all well-established predictors of PWV, such as age, systolic BP or mean BP and pulse pressure, sex, and heart rate, as well as controlling for conventional risk factors for CVD and use of BP-lowering drugs, the level of insulin remained a significant predictor of PWV (standardized regression coefficient: 0.0122+/-0.0048; P=0.012). In conclusion, the present study found that a higher insulin level was related to a higher PWV. This indicates that hyperinsulinaemia may affect BP and risk of CVD by increasing aortic stiffness.