Relationship between gene polymorphisms and prevalence of myocardial infarction among diabetic and non-diabetic subjects

Interaction between physical exercise and APOE gene polymorphism on cognitive function in older people

We aimed to present an overview of the literature regarding the interaction between physical exercise and APOE gene polymorphism on cognitive function, particularly in patients with Alzheimer's disease (AD). Firstly, this review focused on the effect of the physical exercise on cognitive function, regardless of APOE gene polymorphism. Some studies have shown that a high level of cardiorespiratory fitness is associated with less neuronal damage with an improvement in memory score tests whereas other studies failed to detect any association between physical exercise and cognitive improvement either in healthy individuals or patients with AD. Taken together, standardized protocols and more longitudinal studies are required to provide a better insight into the effects of physical exercise on cognitive function. Although there is no agreement in the literature regarding the effects of physical exercise on cognitive function, it is well established that it improves social interaction and the feeling of well-being, thereby positively contributing to the quality of life of the elderly. Regarding the influence of physical exercise on cognitive function in APOE ε4 allele carriers, the data trend shows that the carriers of allele ε4 for APOE gene were more responsive to the beneficial effects of physical exercise on cognitive function compared with non-carriers. Nevertheless, studies with larger sample sizes will provide more accuracy about this relationship.

Association of APOE and CETP TaqIB Polymorphisms with Type 2 Diabetes Mellitus

Apolipoprotein E (APOE) and cholesteryl ester transfer protein (CETP) play an important role in the lipid metabolism. Dyslipidemia is one of the complications that found in type 2 diabetes mellitus (T2DM) patients. The aim of this study was to investigate the association of APOE and CETP TaqIB polymorphisms with T2DM and its related metabolic parameters in Southern Thai population. Study subjects were 241 T2DM patients and 275 healthy controls. The APOE and CETP TaqIB polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. APOE polymorphism showed a statistical difference in allele frequencies (p = 0.025) and genotype distributions (p <0.001) between T2DM patients and healthy controls. The E4 carriers were associated with a significantly higher TC, and/or LDL-C levels compared to the E2 and E3 carriers, respectively in all subjects and healthy controls. Moreover, CETP TaqIB B2B2 genotype was significantly higher HDL-C levels compared with B1B1, and B1B2 genotypes in all subjects, and T2DM patients. Multiple logistic regression analysis showed that APOE and CETP TaqIB polymorphisms were not associated with T2DM. In conclusion, APOE and CETP TaqIB polymorphisms might not be the genetic risk factors for T2DM in Southern Thai population, however, APOE and CETP TaqIB polymorphisms were associated with serum lipids in healthy controls and T2DM, respectively.

Interaction between endothelial nitric oxide synthase rs1799983, cholesteryl ester-transfer protein rs708272 and angiopoietin-like protein 8 rs2278426 gene variants highly elevates the risk of type 2 diabetes mellitus and cardiovascular disease

Background

The aim of the present study was to examine the association of angiopoietin-like proteins-8 (ANGPTL8) rs2278426, cholesteryl ester-transfer protein (CETP) rs708272 and endothelial nitric oxide synthase (NOS3) rs1799983 variants with type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD), and to investigate the effect of the potential interaction between these variants on disease risk.

Methods

Our study included 272 subjects classified into 68 patients with T2DM, 68 patients with T2DM complicated with CVD and 136 control subjects. ANGPTL8 c194C>T, CETP Taq1B and NOS3 G894T polymorphisms were genotyped using TaqMan^® SNP Genotyping Assay.

Results

The presence of NOS3, ANGPTL8, and homozygous CETP B1 variants were associated with increased risk of T2DM by 3.07-, 2.33- and 1.75-fold, respectively. NOS3 variant was associated with 3.08-fold increased risk of CVD (95% CI 1.70–5.60), while ANGPTL8 C allele was associated with 2.8-fold increased risk of CVD in T2DM patients (95% CI 1.13–6.97). Concomitant presence of both, CETP B1 and NOS3 T allele, associated with increased risk of T2DM, CVD and CVD in T2DM by 8.36-, 6.33- and 7.87-fold, respectively, while concomitant presence of ANGPTL8 variant with either CETP B1 or NOS3 T allele was not associated with increased risk of T2DM or CVD. However, concomitant presence of the three variants together elevated the risk of T2DM by 13.22-fold (p = 0.004), CVD risk by 8.86-fold (p = 0.03) and highly elevated the risk of CVD in T2DM patients by 13.8-fold (p = 0.008).

Conclusions

Concomitant presence of CETP B1, NOS3 T and ANGPTL8 T alleles augments the risk of CVD and T2DM. Further studies to clarify the mechanism of gene–gene interaction in the pathogenesis of CVD and T2DM are needed.

Monogenic causes of elevated HDL cholesterol and implications for development of new therapeutics

Identification of the CETP, LIPG (encoding endothelial lipase) and APOC3 genes, and ana lysis of rare genetic variants in them, have allowed researchers to increase understanding of HDL metabolism significantly. However, development of cardiovascular risk-reducing therapeutics targeting the proteins encoded by these genes has been less straightforward. The failure of two CETP inhibitors is complex but illustrates a possible over-reliance on HDL cholesterol as a marker of therapeutic efficacy. The case of endothelial lipase exemplifies the importance of utilizing population-wide genetic studies of rare variants in potential therapeutic targets to gain information on cardiovascular disease end points. Similar population-wide studies of cardiovascular end points make apoC-III a potentially attractive target for lipid-related drug discovery. These three cases illustrate the positives and negatives of single-gene studies relating to HDL-related cardiovascular drug discovery; such studies should focus not only on HDL cholesterol and other components of the lipid profile, but also on the effect genetic variants have on cardiovascular end points.

The I405V and Taq1B polymorphisms of the CETP gene differentially affect sub-clinical carotid atherosclerosis

Background

Cholesteryl ester transfer protein (CETP) plays a major role in lipid metabolism, but studies on the association of CETP polymorphisms with risks of cardiovascular disease are inconsistent. This study investigated whether the CETP gene I405V and Taq1B polymorphisms modified subclinical atherosclerosis in an asymptomatic Brazilian population sample.

Methods

The polymorphisms were analyzed using polymerase chain reaction in 207 adult volunteers. Serum lipid profiles, oxLDL Ab titers, C-reactive protein and tumor necrosis factor-α concentrations and CETP and phospholipid transfer protein (PLTP) activities were determined, and common carotid artery intima-media thickness (cIMT) was measured using ultrasonography.

Results

No differences in cIMT were observed between the presence or absence of the minor B2 and V alleles in either polymorphism. However, inverse correlations between mean cIMT and CETP activity in the presence of these polymorphisms were observed, and positive correlations of these polymorphisms with PLTP activity and oxLDL Ab titers were identified. Moreover, logistic multivariate analysis revealed that the presence of the B2 allele was associated with a 5.1-fold (CI 95%, OR: 1.26 – 21.06) increased risk for cIMT, which was equal and above the 66^th percentile and positively interacted with age. However, no associations with the V allele or CETP and PLTP activities were observed.

Conclusions

None of the studied parameters, including CETP activity, explained the different relationships between these polymorphisms and cIMT, suggesting that other non-determined factors were affected by the genotypes and related to carotid atherosclerotic disease.

Strong interaction between T allele of endothelial nitric oxide synthase with B1 allele of cholesteryl ester transfer protein TaqIB highly elevates the risk of coronary artery disease and type 2 diabetes mellitus

Background

The present study was conducted to investigate the possible outcome of interaction between endothelial nitric oxide (NOS3) G894T and cholesteryl ester transfer TaqIB variants on the risk of coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM). The sample included a total of 207 CAD patients (102 CAD patients with T2DM and 105 CAD patients without T2DM). There were also 101 patients with T2DM and 92 age- and sex-matched healthy individuals as controls. All study participants were from Western Iran. The sample was genotyped by polymerase chain reaction-restriction fragment length polymorphism.

Results

The presence of NOS3 T allele was not associated with the risk of CAD or T2DM, and the CETP B1 allele was only significantly associated with the increased risk of CAD in total CAD patients (odds ratio (OR) = 5.1, p = 0.019). However, the concomitant presence of both CETP B1 and NOS3 T alleles significantly increased the risk of CAD in total CAD patients (OR = 18.1, p < 0.001), in CAD patients without T2DM (OR = 27.1, p = 0.03), and in CAD patients with T2DM (OR = 13.5, p = 0.002). Also, the presence of both alleles increased the risk of T2DM (OR = 12, p = 0.004).

Conclusions

Our findings, for the first time, indicate that NOS3 T allele strongly interacts with CETP B1 allele to augment the risk of CAD and T2DM in the population of Western Iran.

Association of a DNA polymorphism of the apolipoprotein AI-CIII-AIV gene cluster with myocardial infarction in a Tunisian population

BACKGROUND

Apolipoproteins AI-CIII-AIV play important roles in the metabolism of triglycerides and high-density lipoprotein cholesterol. However, whether genetic variations in the ApoAI-CIII-AIV gene cluster are associated with the risk of myocardial infarction (MI) remains uncertain. In the present study, we examined a possible association of the ApoCIII SacI polymorphism in the ApoAI-CIII-AIV gene cluster with lipid parameters and MI in a sample of the Tunisian population.

METHODS

A total of 326 Tunisian patients with MI and 361 controls were included in the study. Genotypes were determined by polymerase chain reaction--restriction fragment length polymorphism (PCR-RFLP) analysis.

RESULTS

A significant difference in genotype distribution and allele frequency was observed between patients and controls. At the multivariate analysis after adjustment for traditional vascular risk factors, the ApoCIII SacI polymorphism was significantly associated with MI, according to co-dominant and dominant models (co-dominant model odds ratio [OR]: 1.53, 95% confidence interval [CI]: 1.0-2.35, p=0.04; dominant model OR: 2.02, 95% CI: 1.11-3.67, p=0.02). The MI patient group showed a significant higher frequency of the S2 allele compared to the controls (10.2% vs. 6.5%; OR: 1.64, 95% CI: 1.10-2.47, p=0.01). There was no statistically significant association between ApoAI-CIII-AIV cluster gene polymorphism and lipid, lipoprotein, and apolipoprotein levels in both MI patients and controls.

CONCLUSION

In the current study, a significant association between the ApoCIII SacI polymorphism (presence of S2 allele) and MI in the Tunisian population was found.

Association between cholesteryl ester transfer protein TaqIB variants and risk of coronary artery disease and diabetes mellitus in the population of western Iran

AIMS

To shed light on the previously inconsistent results about the association of cholesteryl ester transfer protein TaqIB (CETP TaqIB) variants, high-density lipoprotein cholesterol (HDL-C) levels, and the risk of coronary artery disease (CAD) and type 2 diabetes mellitus (T2DM).

METHODS

To determine the frequency of CETP TaqIB variants and to examine the possible association between CETP TaqIB polymorphism with CAD and T2DM, we studied 207 unrelated patients with CAD, 101 patients with T2DM, and 92 controls. The CETP TaqIB variants were detected by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

Logistic regression analysis indicated that the B1 allele of CETP was significantly associated with increased risk of CAD (odds ratio, OR 1.65 [95% confidence interval, CI 1.2-2.3, p=0.005]) and T2DM (OR 1.7 [95% CI 1.13-2.54, p=0.005]). Adjusted logistic regression analysis for the effects of age, sex, hypertension, diabetes, and hyperlipidemia was performed; and a significant association was found between the B1 allele and risk of CAD (OR 1.9 [95% CI 1-3.6, p=0.049]) in patients with CAD. There were no associations between the CETP alleles and the levels of triglycerides, total cholesterol, low-density lipoprotein cholesterol, and HDL-C in studied groups.

CONCLUSIONS

The results of the present study revealed that the CETP B1 allele is associated with increased risk of CAD and T2DM independent of plasma HDL-C level in our population.

Cholesterol ester transfer protein and apolipoprotein E gene polymorphisms in hyperlipidemic Asian Indians in North India

We determined the distribution of the polymorphic variants of CETP TaqIB and ApoE genes and their association with lipid and anthropometric parameters in hyperlipidemic and normolipidemic Asian Indians in North India. CETP TaqIB and ApoE polymorphism were assayed by PCR-RFLP in hyperlipidemic (n = 220) and normolipidemic (n = 367) subjects. Plasma lipids levels were estimated using commercially available kits from Randox (USA). The distribution of CETP TaqIB genotypes and alleles did not differ between the two groups. The frequency of ApoE ε4 allele was significantly higher in hyperlipidemic than normolipidemic subjects. Serum lipid levels were comparable between subjects with the different CETP TaqIB and ApoE genotypes in the two groups. Multivariate analysis after adjusting for age, sex, BMI, WHR, and total skinfold thickness showed that subjects with the Ε3Ε4 genotype and ε4 allele carriers were at significantly higher odds to develop hyperlipidemia [2.07 (1.29-3.30) and 2.05 (1.30-3.24), respectively] as compared to the other genotypes. ApoE ε4 allele and E3E4 genotype emerged as important genetic markers for hyperlipidemia in this study population.

Effects of interacting networks of cardiovascular risk genes on the risk of type 2 diabetes mellitus (the CODAM study)

BACKGROUND

Genetic dissection of complex diseases requires innovative approaches for identification of disease-predisposing genes. A well-known example of a human complex disease with a strong genetic component is Type 2 Diabetes Mellitus (T2DM).

METHODS

We genotyped normal-glucose-tolerant subjects (NGT; n = 54), subjects with an impaired glucose metabolism (IGM; n = 111) and T2DM (n = 142) subjects, in an assay (designed by Roche Molecular Systems) for detection of 68 polymorphisms in 36 cardiovascular risk genes. Using the single-locus logistic regression and the so-called haplotype entropy, we explored the possibility that (1) common pathways underlie development of T2DM and cardiovascular disease -which would imply enrichment of cardiovascular risk polymorphisms in "pre-diabetic" (IGM) and diabetic (T2DM) populations- and (2) that gene-gene interactions are relevant for the effects of risk polymorphisms.

RESULTS

In single-locus analyses, we showed suggestive association with disturbed glucose metabolism (i.e. subjects who were either IGM or had T2DM), or with T2DM only. Moreover, in the haplotype entropy analysis, we identified a total of 14 pairs of polymorphisms (with a false discovery rate of 0.125) that may confer risk of disturbed glucose metabolism, or T2DM only, as members of interacting networks of genes. We substantiated gene-gene interactions by showing that these interacting networks can indeed identify potential "disease-predisposing allele-combinations".

CONCLUSION

Gene-gene interactions of cardiovascular risk polymorphisms can be detected in prediabetes and T2DM, supporting the hypothesis that common pathways may underlie development of T2DM and cardiovascular disease. Thus, a specific set of risk polymorphisms, when simultaneously present, increases the risk of disease and hence is indeed relevant in the transfer of risk.

The CETP TaqIB polymorphism is associated with the risk of sudden death in type 2 diabetic patients

OBJECTIVE

Type 2 diabetic patients have a high risk of coronary heart disease (CHD) and sudden death. This cardiovascular risk can be partly attributed to low levels of HDL cholesterol. The B2 allele of the CETP TaqIB polymorphism has been repeatedly reported to be associated with high HDL cholesterol levels in both healthy and type 2 diabetic subjects, but its association with CHD is unclear. We investigated the association of the CETP TaqIB polymorphism with CHD, and sudden death in particular, in a prospective cohort of type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

The CETP TaqIB polymorphism was genotyped in 3,124 type 2 diabetic subjects with high cardiovascular risk: the Noninsulin-Dependent Diabetes, Hypertension, Microalbuminuria, Proteinuria, Cardiovascular Events, and Ramipril (DIABHYCAR) study. We used Cox regression analysis to estimate the impact of the TaqIB single nucleotide polymorphism on the CHD events (myocardial infarction or sudden death) during follow-up.

RESULTS

The incidence of CHD was higher in B1B1 homozygotes than in B2 carriers (P = 0.02). This effect was mainly due to sudden death (hazard ratio [B1B1 vs. B2+] = 1.51 [95% CI = 1.05-2.18]). Although the B1 allele was associated in a dose-dependent fashion with lower HDL cholesterol (P < 0.001), the association with sudden death persisted after adjustment for multiple risk factors, including HDL cholesterol levels.

CONCLUSIONS

In type 2 diabetic patients, the CETP TaqIB polymorphism is a good genetic predictor of cardiac mortality. This association is partly independent of the effect on HDL cholesterol levels.

Cholesteryl ester transfer protein B1B1 genotype as a predictor of coronary artery disease in Taiwanese with type 2 diabetes mellitus

Diabetes is known to be a high-risk factor for coronary artery disease (CAD), and lipid abnormalities have been found to possibly contribute to CAD in diabetic patients. Cholesteryl ester transfer protein (CETP) gene TaqIB polymorphism is associated with lipid profile variability, and this polymorphism may be a risk factor for CAD in diabetic patients. To clarify the relationship between CETP TaqIB gene polymorphism and CAD, we enrolled in our study 365 Taiwanese with type 2 diabetes mellitus (101 with CAD and 264 without CAD). The genotype of the subjects for TaqIB polymorphism of CETP in intron 1 was analyzed by using polymerase chain reaction-restriction fragment length polymorphism. The CETP B1B1 genotype (18.8% vs 8.5%, P = .002) and B1 allele (42.1% vs 29.7%, P = .002) were significantly more frequent in diabetic patients with CAD than those without CAD. Logistic regression analysis revealed that the CETP B1B1 genotype was associated with CAD in patients with type 2 diabetes mellitus (odds ratio, 3.18; 95% confidence interval, 1.54-6.54; P = .002). Interestingly, in diabetic patients, serum creatinine levels higher than 1.4 mg/dL were also associated with increased risk for CAD (odds ratio, 2.09; 95% confidence interval, 1.12-3.91; P = .02). Our results suggest that the CETP B1B1 genotype is a strong genetic predictor of CAD in Taiwanese with type 2 diabetes mellitus.

Inhibitors of cholesteryl ester transfer protein – a new approach to coronary artery disease

Despite the use of the statins to lower low-density lipoprotein-cholesterol, leading to major reductions in the mortality and morbidity that is associated with coronary artery disease, considerable mortality and morbidity remains. Increasing high-density lipoprotein (HDL)-cholesterol levels has been associated with reduced coronary artery disease mortality and morbidity in several studies. Inhibition of cholesteryl ester transfer protein (CETP) activity leads to increased HDL-cholesterol. In cholesterol-fed rabbits, antibodies against CETP increased HDL-cholesterol and decreased atherosclerotic lesions. In healthy subjects with mild dyslipidaemia, the CETP inhibitors JTT-705 and torcetrapib increased HDL-cholesterol and decreased low-density lipoprotein-cholesterol. Increasing HDL-cholesterol with CETP inhibitors is a new approach to dyslipidaemia that requires further investigation, especially in patients who have coronary artery disease.

Association of CETP TaqI and APOE polymorphisms with type II diabetes mellitus in North Indians: a case control study

BACKGROUND

Genetic variants of proteins involved in lipid metabolism may play an important role in determining the susceptibility for complications associated with type II diabetes mellitus (T2DM). Goal of the present study was to determine the association of cholesteryl ester transfer protein TaqI B, D442G, and APOE Hha I polymorphisms with T2DM and its complications.

METHODS

Study subjects were 136 patients and 264 healthy controls. All polymorphisms were detected using PCR-RFLP and statistical analysis done with chi2 test and ANOVA.

RESULTS

Although CETP TaqI B polymorphism was not associated with the T2DM, yet B1B2 genotype was significantly (p = 0.028) associated with high risk of hypertension in diabetic patients (OR = 3.068, 95% CI 1.183-7.958). In North Indians D442G variation in CETP gene was found to be absent. Frequency of APOE HhaI polymorphism was also not different between patients and controls. In diabetic patients having neuropathy and retinopathy significantly different levels of total-cholesterol [(p = 0.001) and (p = 0.029) respectively] and LDL-cholesterol [(p = 0.001) and (p = 0.001) respectively] were observed when compared to patients with T2DM only. However, lipid levels did not show any correlation with the CETP TaqI B and APOE Hha I genetic polymorphisms.

CONCLUSION

CETP TaqI B and APOE HhaI polymorphism may not be associated with type II diabetes mellitus in North Indian population, however CETP TaqI B polymorphism may be associated with hypertension along with T2DM.