Apolipoprotein B signal peptide polymorphism in relation to lipids and diabetes in male CAD patients

Association between apolipoprotein B gene polymorphisms and the risk of coronary heart disease (CHD): an update meta-analysis

OBJECTIVE

Polymorphisms in the apolipoprotein B (apoB) gene have been reported to be associated with coronary heart disease (CHD). However, the results on this topic are conflicting. The present study aims to derive a more precise estimation of the relationship between CHD and apoB genetic polymorphisms by meta-analysis.

METHODS

We identified a total of 54 studies involving 7236, 10,912, and 14,102 individuals, respectively, for EcoRI, XbaI, and SpIns/Del polymorphisms by searching in PubMed, Web of Science, Google Scholar, the Cochrane Library, Wanfang Data, SinoMed, and CNKI. We utilized RevMan 5.0 software to perform the meta-analyses.

RESULTS

A significant statistical association between apoB EcoRI polymorphism and CHD was observed under an allelic (p = 0.001, odds ratio (OR) = 1.33, 95% confidence interval (CI) = 1.12-1.57), dominant (p = 0.005, OR = 1.22, 95% CI = 1.06-1.40), and recessive (p = 0.04, OR = 1.33, 95% CI = 1.01-1.74) model. We also found similar association of apoB SpIns/Del polymorphism with CHD. However, we did not find association between apoB XbaI polymorphism and CHD.

CONCLUSION

The current meta-analysis found an association of EcoRI polymorphism and SpIns/Del polymorphism with an increased risk of CHD. No significant association between apoB XbaI polymorphism and CHD we observed in the present study.

ApoB gene SpIns/Del, XbaI polymorphisms and myocardial infarction: a meta-analysis of 7169 participants

BACKGROUND

Apolipoprotein B (ApoB) gene signal peptide insertion/deletion (SpIns/Del, I/D) and XbaI polymorphisms have been associated with susceptibility to myocardial infarction (MI). However, the results of studies on this association are still controversial.

OBJECTIVE AND METHODS

This study explored reports published from 1986 to 2008 regarding the association of ApoB gene SpIns/Del and XbaI polymorphisms with MI. A meta-analysis including 7169 participants from 19 individual studies was performed. The pooled odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs) were evaluated by fixed-effect or random-effect models.

RESULTS

A significant relationship between ApoB SpIns/Del gene polymorphism and MI was found under allelic (OR: 1.270, 95% CI: 1.090-1.480, P = 0.002), recessive (OR: 1.360, 95% CI: 1.130-1.630, P = 0.0009), dominant (OR: 1.091, 95% CI: 1.037-1.146, P = 0.001), homozygous (OR: 1.610, 95% CI: 1.330-1.950, P <0.00001) and heterozygous (OR: 1.081, 95% CI: 1.020-1.146, P = 0.009) genetic models. A marginal relationship between ApoB XbaI polymorphism and MI was found under a dominant genetic model (OR: 1.083, 95% CI: 1.004-1.168, P = 0.039). No significant association was detected under other genetic models (P >0.05). However, in the non-European subgroup analysis, increased MI risk emerged under all genetic models (P <0.05).

CONCLUSION

ApoB SpIns/Del gene polymorphism was positively associated with increased MI risk. D allele and DD genotype carriers might be predisposed to MI susceptibility. The ApoB XbaI gene polymorphism locus had a significant positive association with increased MI risk only in the non-European population. T allele and TT genotype carriers might be susceptible to MI in the non-European population. On the contrary, the ApoB gene XbaI restriction fragment length polymorphism was not associated with increased MI risk in the entire population, particularly in the European population.

Correlation between haplotype of apolipoprotein B gene and natural longevity persons in Uygur nationality

This paper investigated the correlation between polymorphisms and haplotypes in the apolipoprotein B (apoB) gene (SP-I/D, Xbal-RFLP, VNTR) and natural longevity persons among the Uygur people in Xinjiang. For this purpose, 191 healthy Uygur individuals aged above 90 from Hetian area of Xinjiang were recruited, and another 53 persons aged 65-70 from the same nationality, the same region and with the same gender ratio, served as the control group. Genotyping was performed by PCR-SSP, PCR-RFLP and PCR-sequencing methods. Logistic regression analyses revealed that the frequencies of X+ X+ genotype, M and L alleles and the genotypes composed of M and L were significantly higher in the longevity group than in the control group. In haplotype analyses, we found that, in the long-lived people, the frequency of haplotypes composed of the X+ and M alleles was significantly higher whereas the frequency of haplotypes composed of the X-and S alleles was significantly lower (both P<0.05) I than those of their controls. These results indicated that the S allele, SS genotype and X+-S, D-S, D-X+-S haplotypes were the possible adverse factors, whereas the M, L alleles, X+X+, MM, ML, LL genotypes and I-X+-M, X+-M haplotypes were the possible protective factors for the naturally long-lived Uygur people in China.

Molecular variation at the apolipoprotein B gene locus in relation to lipids and cardiovascular disease: a systematic meta-analysis

Apolipoprotein B (apoB) is the sole protein component of low-density lipoprotein (LDL) and is thought to play an important role in atherogenesis. We performed a meta-analysis of the associations between the three most frequently investigated polymorphisms (XbaI, signal peptide insertion/deletion, EcoRI) in the apolipoprotein B (APOB) gene, lipid parameters, and the risk of ischemic heart disease (IHD). We restricted our analysis to Caucasians. Homozygotes for the XbaI X+ allele had significantly elevated levels of LDL cholesterol (LDL-C) and apoB, but a decreased risk (OR=0.80; 95%CI: 0.66-0.96) of IHD. Homozygosity for the signal peptide deletion allele was associated with similarly increased levels of LDL-C and apoB, and with an increased risk of IHD (OR=1.30; 95%CI: 1.08-1.58). Subjects homozygous for the rare EcoRI allele had significantly decreased levels of total and LDL cholesterol, but unaltered risk of IHD. We conclude that all three polymorphic apoB sites are associated with altered lipid levels, but not necessarily with a consistently altered risk of IHD. These data suggest that the relationship between apoB levels, hypercholesterolemia and IHD risk cannot have a simple molecular basis in the apoB gene.

Interaction between SREBP-1a and APOB polymorphisms influences total and low-density lipoprotein cholesterol levels in patients with coronary artery disease

In this study, we examined the insertion/deletion (Ins/Del) and XbaI polymorphisms of the apolipoprotein B (APOB) gene and the -36delG polymorphism in the sterol regulatory element binding protein-1a (SREBP-1a) gene in 298 patients with non-diabetic angiographically assessed coronary artery disease (CAD), and 188 healthy controls, from a Brazilian population of European descent. Del/X+ haplotype carriers had higher levels of total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) in patients (TC, p = 0.05; LDL-C, p = 0.049) and controls (TC, p = 0.004; LDL-C, p = 0.013). No association was detected between the SREBP-1a-36delG polymorphism and lipid levels, but a significant interaction effect between APOB and SREBP-1a polymorphisms was observed in the patient sample on TC (p = 0.005) and on LDL-C (p = 0.019) levels. Carriers of the APOB Del/X+ haplotype and SREBP-1a G-G- genotype showed the highest levels of these lipid parameters. This effect of interaction was not observed in the control sample. Despite the associations with lipids, these polymorphisms were not associated with CAD risk or severity in this sample.