Iwona Zak

The 242T variant of the CYBA gene polymorphism increases the risk of coronary artery disease associated with cigarette smoking and hypercholesterolemia.

ObjectivesHypercholesterolemia and cigarette smoking increase superoxide anion production, which is involved in many proatherosclerotic processes. NAD(P)H oxidases are the main source of superoxides in the vasculature, and the phagocyte oxidase (p22phox) encoded by the CYBA gene is a critical component of NAD(P)H oxidases. The 242T CYBA allele is associated with an increased low-density lipoprotein oxidation and superoxide production. This report focuses on the interactions between C242T CYBA polymorphism and traditional risk factors of coronary artery disease (CAD), such as cigarette smoking and hypercholesterolemia. MethodsWe have studied 341 individuals, including 172 patients with angiographically confirmed CAD and 169 blood donors with no known history of cardiovascular disease. The C242T CYBA polymorphism was genotyped using the PCR-restriction fragment-length polymorphism method. To determine the possible interactions between CYBA genotypes and the traditional risk factors for CAD, we used multivariate logistic regression analysis (cumulative effects) and the 4×2 table approach (synergistic/antagonistic effects). ResultsWe have found a strong cumulative effect of the 242T allele carrier state and cigarette smoking and hypercholesterolemia. The risk of CAD associated with the presence of cigarette smoking and hypercholesterolemia was stronger in 242T carriers (odds ratio=17.88, P<0.00000) than in CC homozygotes (odds ratio=3.75, P<0.00000). Estimated CAD risk associated with the presence of the 242T allele and both traditional risk factors was ≈500% greater than the risk predicted by assuming additivity of effects (synergy index, 5.08). ConclusionThe 242T allele interacts with cigarette smoking and hypercholesterolemia to increase the risk of CAD; this risk is probably associated with the cumulative/synergistic effect of the 242T allele and both the traditional risk factors.

The T Allele of the 677C>T Polymorphism of Methylenetetrahydrofolate Reductase Gene is Associated With an Increased Risk of Ischemic Stroke in Polish Children

Ischemic stroke is a very rare and multifactorial disease in children. The aim of the study was to analyze the relationship between the methylenetetrahydrofolate reductase (MTHFR) 677C>T polymorphism and stroke in Polish children and to observe whether there is any significant transmission of MTHFR alleles from heterozygous parents to their affected offspring. We analyzed 64 patients with stroke, 122 parents, and 59 healthy children. The MTHFR polymorphism was genotyped using polymerase chain reaction (PCR)-restriction fragment length polymorphism. The T allele was more frequent in the stroke group (38%) than in controls (25%, P = .029, odds ratio = 1.84). We also found higher frequency of T allele in male patients compared to male controls (46% vs. 25%, P = .009, odds ratio = 2.53). The number of T allele carriers was again more prevalent in boys with stroke (71%) than in healthy boys (45%, P = .023, odds ratio = 3.09). The T allele was significantly transmitted in male patients (P < .019). We conclude that the MTHFR 677C>T polymorphism may be considered as a genetic risk factor of childhood stroke, especially in boys.

Modification of the Coronary Artery Disease Risk Associated with the Presence of Traditional Risk Factors by Insertion/Deletion Polymorphism of the ACE Gene

Cigarette smoking, hypercholesterolemia, and obesity influence the renin-angiotensin system (RAS) functions including an increased synthesis of the angiotensin I converting enzyme (ACE). Thus in the present work we explore the interactions of the ACE gene insertion/deletion (I/D) polymorphism and traditional risk factors. The study cohort included 341 subjects composed of 172 patients with angiographically confirmed CAD and 169 blood donors without a history of cardiovascular diseases. The I/D polymorphism was genotyped using polymerase chain reaction (PCR) methodology. To determine the interactions between the ACE genotypes and traditional risk factors the epidemiologic approach was used (4 x 2 tables and the synergy measures). The frequency of the DD genotype was significantly higher in patients than in controls (33.7% versus 21.3%, odds ratio [OR] = 1.88, 95% CI; 1.13-3.15, p = 0.010), but greater differences were found in males (35.7% versus 20.5%, OR = 2.15, 95% CI: 1.14-4.04, p = 0.010). We found a synergy of the DD genotype with smoking (SI = 1.88, SIM = 1.22), total cholesterol > or =5 mmol/l (SI = 2.12, SIM = 1.31) and elevated low density lipoprotein (LDL) cholesterol level (> or =3 mmol/l) (SI = 1.78, SIM = 1.14). The presence of the D allele (DD + ID subjects) also increased the risk of coronary artery disease (CAD) associated with the presence of elevated total cholesterol and LDL cholesterol (SI = 1.69, SIM = 1.18, in both cases), elevated level (> or =1.7 mmol/l) of triacylglycerols (SI = 1.81, SIM = 1.18) and overweight/obesity (SI = 4.25, SIM = 2.36). In each case the estimated CAD risk was greater than that predicted by assuming the additivity of effects (the risk increased from 69% for the D allele - total cholesterol interaction to 325% for the D allele - overweight/obesity). The statistical significance was also confirmed by a multiplicative model of synergy. The DD genotype/D allele of the ACE gene increases the risk of CAD associated with the presence of traditional risk factors.

Synergistic effects between 561A > C and 98G > T polymorphisms of E-selectin gene and hypercholesterolemia in determining the susceptibility to coronary artery disease

Coronary artery disease (CAD) is a multifactorial disease that results from the interaction between genetic and traditional risk factors. The endothelium dysfunction plays a key role in the progression of atherosclerotic lesions. E-selectin is a marker of endothelium dysfunction. The aim of the present study was to find a relationship between 561A > C and 98G > T polymorphisms of E-selectin gene and CAD as well as interactions between these polymorphic variants and traditional risk factors of the disease in determining the susceptibility to CAD. The study population included 191 patients with angiographically documented CAD and 203 blood donors. The analysis of genetic polymorphisms was performed using the polymerase chain reaction-restriction fragment length polymorphism method. We found that the frequencies of 561C and 98T alleles of E-selectin gene and carriers of C and T alleles were similar in the entire groups as well as in the age-and sex-matched subgroups. We observed a strong significant correlation between those two polymorphisms; almost all subjects possessing one “proatherosclerotic” allele of E-selectin gene also had the second allele (r = 0.963, P < 0.0001). There were also synergistic effects between both polymorphisms and hypercholesterolemia (but not with smoking or overweight) in determining the susceptibility to CAD. The present study points to synergistic interactions between 561A > C or 98G > T polymorphisms of E-selectin gene and hypercholesterolemia that cause a significant increase in the susceptibility to CAD.

Synergistic effects of the polymorphisms in the PAI-1 and IL-6 genes with smoking in determining their associated risk with coronary artery disease

OBJECTIVES To assess the relationship between IL-6 and PAI-1 polymorphisms and coronary artery disease (CAD) and to observe the interactions between these polymorphic variants and smoking in the CAD risk. DESIGN AND METHOD The study population consisted of 178 patients with angiographically documented CAD and 202 blood donors. The analyses of genetic polymorphisms were performed using the PCR-RFLP method. RESULTS The frequency of PAI-1 5G allele was higher in the entire CAD group than in control group (p=0.04, OR=1.35). Also the 5G allele carriers (4G5G+5G5G) were more frequent in patients than in controls (p=0.03, OR=1.93). The number of women carrying 5G allele was again significantly higher among patients (OR=10.95 p=0.0075). The IL-6 C allele frequency was higher only in the CAD male subgroup (p=0.035, OR=1.44). We found synergistic and cumulative effects between specific genotype patterns and smoking in determining the risk of CAD, especially between PAI-1(4G5G+5G5G)+IL-6(CC) and smoking (SIM=4.18 and p=0.0005, OR=9.20, respectively). CONCLUSIONS There are synergistic and cumulative effects of 5G allele of PAI-1 polymorphism and C allele of IL-6 polymorphism with smoking in determining their associated risk with CAD.

Synergistic effect between polymorphisms of PPARA and ABCA1 genes on the premature coronary artery disease.

Objective — Progression of atherosclerosis, the main reason of cardiovascular diseases, depends on multiple genetic and environmental factors. Polymorphic variants of genes involved in the lipids metabolism may genetically differentiate human populations and determine a susceptibility to the disease. The aim of the present study was to evaluate a possible interaction between R219K polymorphism of ABCA1 gene and G>C polymorphism in intron 7 of PPARA gene in determining the risk of the CAD. Methods — We studied 358subjects: 178patients with angiographically confirmed CAD and 180 blood donors without history of CAD. Polymorphisms were genotyped using the PCR-RFLP method. Results — In spite of a small or no correlation between single polymorphism and CAD we observed that the frequencies of AA+GC, CC genotype pattern (ABCA1 and PPARA gene) were significantly higher in CAD group than in controls. OR values were especially high in multiple logistic regression and were higher for male subgroups.The synergy index value equals 3.98 and indicates a quite strong synergistic effect between the analysed polymorphisms. We also observed that C allele carriers of PPARA gene had a significantly lower total and LDL-cholesterol level. Conclusion — The present study shows that R219K polymorphism of ABCA1 gene and G>C polymorphism in intron 7 of PPARA gene act cumulatively and synergistically in determining the risk of premature CAD.

Protective effect of R allele of PON1 gene on the coronary artery disease in the presence of specific genetic background.

Background: Genetic susceptibility to CAD may be determined by polymorphic variants of genes encoding isoforms involved in the processes important in the pathogenesis of atherosclerosis, including lipids disorders. Participation of single polymorphic variants is relatively small, however its significance may increase in the presence of specific genetic or environmental background. Aim: The aim of the study was an evaluation a possible association between single polymorphic variants of PON1, APOE, ABCA1 and PPARA genes and CAD and looking for specific multigene genotype patterns which differentiate study groups. Materials and methods: We studied 358 subjects:178 patients with angiographically confirmed CAD and 180 blood donors without history of CAD. Polymorphisms were genotyped using PCR-RFLP method. Results: We observed statistically significant differences in the frequencies of R allele and R allele carriers of PON1 gene between CAD and controls. The distribution of genotypes and alleles of other analyzed genes did not differentiate the study groups, however the presence of specific genotypes (APOE– ɛ3ɛ3, ɛ3ɛ2, ABCA1 – AG, PPARA – GG) increased the protective effect of R allele. Conclusion: The present study revealed an independent protective association between carrier-state of PON1 R allele and CAD. This protective effect was especially strong in the presence of specific genotype arrangements of other analyzed genes.

The CYBA gene A640G polymorphism influences predispositions to coronary artery disease through interactions with cigarette smoking and hypercholesterolemia.

The CYBA gene encodes the p22phox peptide, an essential subunit of vascular NADPH oxidases. The aim of the study was to analyze potential interactions between CYBA gene A640G polymorphism and traditional risk factors of atherosclerosis. We studied 320 subjects: 160 patients with coronary artery disease (CAD) and 160 controls. The results of interactions were interpreted on the basis of synergy index values (SI, SIM). The 640G allele interacted with cigarette smoking (SI = 2.02, SIM = 2.32). Even greater increase of the CAD risk was found whenever the 640G allele interacted with both smoking and hypercholesterolemia (SI = 2.70, SIM = 3.60). The results suggest that the A640G polymorphism may influence individual predispositions to CAD through interactions with smoking and hypercholesterolemia.

The D allele of angiotensin I-converting enzyme gene insertion/deletion polymorphism is associated with the severity of atherosclerosis

Abstract Background: Angiotensin II is produced primarily by angiotensin I-converting enzyme (ACE) within atherosclerotic lesions and ACE level in plaques correlates with the severity of vessel wall damage. Therefore, we investigated the possible association of ACE gene insertion/deletion (I/D) polymorphism and the severity of atherosclerosis, estimated on the basis of the number of coronary stenoses and critical arterial occlusions observed during coronary angiography. Methods: The study cohort included 172 patients with angiographically confirmed premature coronary artery disease. The ACE gene I/D polymorphism was genotyped using a PCR method. Results: The frequencies of DD genotype, D allele carrier-state (DD+ID genotypes) and the D allele increased with the number of stenoses in coronary vessels. D allele carriers (DD+ID genotypes) were more frequent in the subgroup of patients with stenoses in at least four coronary vessels than in other patients including subjects with one-, two- and three-vessel disease (97.4% vs. 74.4%, OR=13.05, 95% CI: 1.81–100.00, χ2=9.84, p=0.0017). Furthermore, the D allele was significantly more frequent in patients with critical arterial occlusions (>90%) than in subjects without critical stenoses (61.1% vs. 49.3%, χ2=9.84, p=0.023). Conclusions: The ACE I/D polymorphism influences individual differences in severity of coronary artery disease and the D allele promotes generation of numerous and critical atherosclerotic lesions. Clin Chem Lab Med 2008;46:446–52.

Combined "pro-atherosclerotic" variants of the ACE and APOE genes increase the risk of the coronary artery disease associated with the presence of cigarette smoking.

Objective — Cigarette smoking increases the synthesis of angiotensin-I converting enzyme (ACE) and induces oxidative modifications of the apolipoprotein E (apo E).Thus we explored the gene-environment interactions between APOE gene epsilon and ACE gene insertion/deletion polymorphisms and cigarette smoking in coronary artery disease (CAD) patients. Methods — We analysed 360 subjects: 171 CAD patients and 189 blood donors without a history of cardiovascular diseases. ACE and APOE polymorphisms were genotyped using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods, respectively.To determine gene-environment interactions, epidemiological methodology was used. Results — The ACEDD genotype was a rather weak risk factor of CAD in the analysed population (OR = 1.87, P= 0.01).The differences in allele and genotype distribution of the APOE polymorphism were not statistically significant.The carriers of the combined genotype ACEDD + APOEɛ4ɛ4,ɛ3ɛ4,ɛ2ɛ4 were more frequent in patients, however, the differences were on the bound of statistical significance (P= 0.08). Logistic regression analysis showed that the ACEDD + apo Eɛ4ɛ4,ɛ3ɛ4,ɛ2ɛ4 cigarette smokers were much more frequent in the CAD group (OR = 11.68, 95%CI; 1.52-246.43, P= 0.009).We confirmed these results using the 4 ≈ 2 table approach and we found a synergistic effect of the ACEDD + APOEɛ4ɛ4,ɛ3ɛ4,ɛ2ɛ4 combined genotype and cigarette smoking (SI = 10.52, SIM = 6.09). Conclusions — We demonstrated the existence of the synergistic effect between cigarette smoking and the contemporaneous carrier-state of APOE e4 and ACED alleles which increased the risk of CAD to a large extent.