Smoking confers a MTHFR 677C>T genotype-dependent risk for systemic atherosclerosis: results from a large number of elderly autopsy cases that died in a community-based general geriatric hospital

The TT Genotype of the MTHFR 677C>T Polymorphism Increases Susceptibility to Premature Coronary Artery Disease in Interaction with Some of the Traditional Risk Factors

Background: The presence of several risk factors (genetic and non-genetic) has greater impact on the risk of premature coronary artery disease (CAD) than single risk factor. Objective: The aim of the study was to establish possible relations between genotypes and alleles of 677C>T polymorphism ofMTHFRgene and some traditional risk factors e.g. elevated levels of lipid parameters and smoking in development of premature CAD. Methods: The groups comprised 152 patients with angiographically documented premature CAD (aged 42.9 ± 5.5) and 121 age-matched blood donors (aged 42.3 ± 6.5) were studied. TheMTHFR677C>T polymorphism was genotyped with Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method. Results: Patients with TT genotype who simultaneously smoked had increased risk of premature CAD compared to non-smoking cases with CC genotype (OR = 24.62). We also found that individuals with TT genotype and elevated LDL-cholesterol (LDL-chol.) level had significantly higher risk of CAD (OR = 9.92) than individuals with normal LDL-chol. level and CC genotype. Conclusions: The present study shows that simultaneous presence ofMTHFRTT genotype and smoking or elevated levels of LDL-chol. influences the risk of premature CAD. This findings give interesting contribution to gene-environment interaction problem that may have clinical implications in the future.

A gene variant in the Atp10d gene associates with atherosclerotic indices in Japanese elderly population

BACKGROUND

ATP10D belongs to a subfamily of P-type ATPases implicated in phospholipids translocation from the exoplasmic to the cytoplasmic leaflet of cellular biological membrane. Previous genome-wide association study (GWAS) identified that a variant in Atp10d gene (rs2351791) associates with serum lipid profile and myocardial infarction. The objective of this study is to assess the effect of this variant on atherosclerosis in Japanese elderly population.

METHOD

Consecutive autopsy cases registered in JG-SNP study were recruited (n = 1536). The samples were pathologically assessed for atherosclerosis using macroscopic examination of the formalin-fixed arteries, and coronary stenotic index (CSI), intracranial atherosclerotic index (ICAI) and pathological atherosclerotic index (PAI), which represent systemic arteries were calculated. The variant rs2351791 (G/T) in Atp10d gene was genotyped by Taqman genotyping assay and association determined.

RESULT

Both CSI and ICAI were significantly higher in GG genotype than GT genotype and TT genotype (p = 0.003 and p = 0.001, respectively). Both associations remained significant in minor allele dominant model after adjusting for age, hypertension, diabetes, HDL, smoking and drinking (p = 0.001 and p = 0.001, respectively). PAI was not associated with this variant. Consistent with the previous report, plasma HDL cholesterol level was lower in GG genotype compared to GT + TT genotypes (p = 0.001).

CONCLUSION

The rs2351791 SNP in the Atp10d gene affects the susceptibility for cardiac and intracranial vascular stenosis in the elderly Japanese population.

Association of COMT gene polymorphisms with systemic atherosclerosis in elderly Japanese

AIM

Atherosclerotic disease is a major health problem among the elderly, which arises from a complex interaction between genetic and environmental factors. The catechol-O-methyltransferase (COMT) gene encodes an enzyme that degrades catecholamines and estrogens to less active metabolites. The objective of this study was to examine whether polymorphisms of the COMT gene affected the severity of atherosclerotic disease in a Japanese elderly population.

METHOD

A total of 1536 autopsy cases of hospital deaths were assessed for the degree of pathological atherosclerotic index (PAI), coronary stenotic index (CSI) and intracranial stenotic index (ICAI), which were obtained by macroscopic examination of the luminal surface of formalin-fixed arteries. Two single nucleotide polymorphisms (SNPs) in the COMT gene, rs4633 (C/T) and rs4680 (G/A) were genotyped. The rs4680 (G/A) corresponds to a functional SNP with the substitution of valine to methionine.

RESULT

The CC genotype of rs4633 (C/T) and the GG genotype of rs4680 (G/A) showed a significantly higher degree of PAI and the association remained positive after adjustment for age, hypertension, diabetes, smoking and drinking (p=0.035 and p=0.031, respectively). There were no significant associations between COMT genotypes and CSI or ICAI. When male and female subjects were analyzed separately, the association was observed only in female subjects (p=0.012 and p=0.027) after adjustment for age, hypertension, diabetes, smoking and drinking.

CONCLUSION

The functional SNP in the COMT gene associated with the severity of atherosclerosis in a Japanese elderly population, whereby the influence of the genotype appears to be stronger in females than in males.

Folate intake and methylenetetrahydrofolate reductase gene polymorphisms as predictive and prognostic biomarkers for ovarian cancer risk

Folic acid and methylenetetrahydrofolate reductase (MTHFR) may affect the development of human cancer. However, few studies have evaluated folate intake and MTHFR in susceptibility to and prognosis of patients with ovarian cancer. We conducted a prospective case-control study in 215 ovarian cancer patients and 218 controls (all Chinese) between Jan. 2004 and Jan. 2007. MTHFR C677T genotyping was done by PCR-RFLP. All patients were followed up until Dec. 2010. We found a 2.43-fold increased risk of ovarian cancer among MTHFR 677TT carriers, and a decreased risk of ovarian cancer in individuals with high folate intake (OR = 0.54, 95% CI = 0.32-0.94). Cox regression survival analysis showed that among the ovarian cancer patients, those carrying the 677TT genotype had a higher risk of death (HR = 2.17, 95% CI = 1.20-4.79), while high folate intake was associated with a lower risk of death (HR = 0.43, 95% CI = 0.33-0.88). Moreover, MTHFR 677CC carriers with higher folate intake showed a lower risk of death from ovarian cancer (HR = 0.32, 95% CI = 0.27-0.82). In summary, high folate intake may lessen susceptibility and improve the prognosis of ovarian cancer patients, while the MTHFR 677TT genotype appears to increase ovarian cancer risk and worsen its prognosis in a Chinese population.