LPA Rs10455872 Research Articles

Diabetes Mellitus influence in Lipoprotein(a) gene expression and association to coronary artery disease

Abstract Introduction Lp(a) and type 2 diabetes mellitus are both known and established risk factors for the development of coronary artery disease (CAD). Lp(a) levels are 75% to 95% heritable and predominately determined by single-nucleotide variants at the LPA gene; rs3798220 is one of the most studied variants and accounts for a significant portion of Lp(a) levels. Whether diabetes could influence the LPA rs3798220 account for Lp(a) levels is unknown. Aim Evaluate whether there is a different association between polymorphism LPA rs3798220 T>C and Lp(a) levels and their association with CAD in diabetic and non-diabetic populations. Methods 3,209 subjects (mean age 59.3±8.9 years, 76.3% male were selected from the data set of the Research Center. The LPA rs3798220 T>C was genotyped with the TaqMan PCR assay (Applied Biosystems 7300 Real-Time). This genetic variant has a minor allele frequency (MAF) <2%; hence, the risk homozygous CC is a rare genotype, and we used the heterozygous CT in our analysis. Lp(a) biochemical levels were measured in all participants. From the 3,209 participants, 810 had diabetes, and 2399 were no diabetics. For each group, chi-squared tests were used to determine the association of CAD prevalence by genotype, and t-tests were used to evaluate differences in CAD prevalence by Lp(a) levels. Results In non-diabetic subjects, LPA TC was significantly associated with CAD in non-diabetic subjects compared with TT (p<0.0001). Similarly, Lp(a) was higher in the CAD population (37.2±39.7) compared to the healthy population (25.6±30.0) (p<0.0001). In diabetic group, Lp(a) was higher in the CAD population (38.5±41.4) compared to the population without CAD (23.9±29.2) (p<0.0001). Nevertheless, there was no difference in genotype between CAD and non-CAD patients (p=0.710). Conclusion The LPA rs3798220 T>C variant in non-diabetic group can explain high Lp(a) levels and their association with CAD. However, in patients with diabetes, Lp(a) is elevated in CAD patients besides the fact that no significant genotype differences were displayed. Non-genetic influences like behavioural factors or even epigenetic changes may probably explain high Lp(a) levels in this population.

Does the LPA genotype have a role in coronary artery disease risk beyond Lp(a) values?

Abstract Introduction High lipoprotein(a) [Lp(a)] concentrations are one of the most important genetically determined risk factors for coronary artery disease (CAD). Many functional single nucleotide polymorphisms (SNPs) of the LPA gene have pronounced effects on Lp(a) concentrations. Studies show that rs3798220 polymorphism is strongly associated with Lp(a) concentration and also with risk of CAD. Goal: To evaluate if LPA rs3798220 T>C is associated with CAD beyond its effect on Lp(a) levels. Methods We performed a case-control study with 3,157 individuals (1,721 CAD patents and 1,436 controls). The LPA rs3798220 T>C was genotyped with the TaqMan PCR assay (Applied Biosystems 7300 Real-Time). This variant has a minor allele frequency (MAF) <2%; hence, the risk homozygous CC is a rare genotype, and we used the heterozygous CT in our analysis. Laboratory analysis was performed, and Lp(a) biochemical levels were measured in the cases and controls. Chi-squared tests were used to determine differences by genotype in CAD association (in cases and controls). We also reported a multivariate logistic regression to test if this LPA variant is still independently associated with CAD after adjustment to Lp(a) levels and traditional risk factors for CAD. Results Wild-type genotype TT was increased in the group without CAD, whereas the genotype TC was higher in patients with CAD (p<0.0001). After multivariate logistic regression, adjusted for traditional risk factors, the TC genotype remained in the equation as an independent risk factor for CAD (OR=2.36; 95%CI: 1.54–3.61; p<0.0001). When the multivariate regression analysis is adjusted for traditional risk factors plus Lp(a) levels, the TC genotype remains in the equation as independently associated with CAD despite being substantially attenuated (OR=1.67; 95%CI: 1.07–2.60; p=0.025). Conclusion LPA rs3798220 T>C may be an independent risk factor for CAD beyond the effect of rising Lp(a) levels. Perhaps testing for the genetic determinants of Lp(a) relative to direct measurement of Lp(a) level could provide additional prognostic utility.

The effect of the LPA gene on aortic valve calcification in a Portuguese population

Abstract Introduction Aortic valve calcium (AVC) deposition is one of the mechanisms behind aortic sclerosis and stenosis. There is a known association between LPA gene rs3798220 T>C polymorphism and the development of severe aortic stenosis. However, it is still unknown if it has been a driving factor since the early stages of the disease. Objective Investigate, in our population, the association between the LPA gene variant rs3798220 T>C and aortic valve calcification. Methods AVC was measured in 451 consecutive individuals from the prospective arm of the GENEMACOR study with a mean age of 63.4±9.7 years, 58.8% male. AVC score was performed by cardiac computed tomography and reported as Agatston units. Results were separated into two groups (Group A: AVC=0; Group B: AVC>0). Lp(a) levels were analyzed in the different groups. Each individual was genotyped for LPA rs3798220 T>C. This variant has a minor allele frequency (MAF)<2%; hence, the risk homozygous CC is a rare genotype, and we used the heterozygous CT in our analysis. The bivariate and multivariate logistic regression analysis evaluated the presence of AVC adjusting to traditional risk factors (TRFs) and the LPA heterozygous genotype (CT). Results LP(a) levels were higher in the CT allele versus the homozygous TT, but this difference did not reach a statistical significance. After multivariate analysis, the heterozygous LPA rs3798220 T>C polymorphism remained an independent risk factor for the presence of aortic valve calcification (OR=12.14, p=0.002) together with age (OR=1.13, p<0.0001), arterial hypertension (AHT) (OR=1.96, p=0.006) and alcohol consumption (OR=2.46, p=0.016). Conclusion The LPA gene variant rs3798220 T>C is associated with the presence of aortic valve calcification in a Portuguese population. In such an age-dependent disease as aortic stenosis, the inversion in the age pyramid will see a dramatic increase in the prevalence of aortic stenosis. The early identification of high-risk individuals might enable prompt traditional risk factors control and disease prevention. Larger population studies may help to determine if this difference is driven by Lp(a) levels.

Association of the lipoprotein(a) gene (LPA) p.Ile4399Met variant with lipoprotein(a) level and cardiovascular events in patients following coronary artery bypass grafting under 65 years of age

Abstract Introduction Lipoprotein(a) (Lp[a]), a well-known risk factor for atherosclerotic cardiovascular disease, is largely determined by variation in the Lp(a) gene (LPA) locus encoding apolipoprotein(a). The LPA gene Ile4399Met (rs3798220) variant has been previously reported to have a strong association with the Lp(a) level in patients with coronary artery disease (CAD), however, its prevalence in the middle-age patients after coronary artery bypass grafting (CABG) has not been investigated. Purpose To assess the frequency of the LPA gene c.5673A>G variant (p.Ile4399Met; rs3798220) in Polish patients with CAD following CABG under 65 years of age and determined its association with laboratory and clinical variables. Materials and Methods We studied 215 patients with stable CAD, aged 59.5±4.9 years, who underwent primary and isolated CABG surgery (at age of 57.8±5.4 years), including 195 (90.8%) male. Clinical characteristics and analysis of the LPA c.5673A>G variant were performed. Results The genotype distribution was as follows: AA – 192 (89.3%), AG – 19 (8.8%), and GG – 4 (1.9%). The c.5673G allele carriers had higher Lp(a) level (106.5 [IQR 77.9-149.7] vs 10.4 [IQR 4.4-43.0] mg/dL, p<0.001) compared with non-carriers. Among the c.5673G allele carriers, Lp(a) correlated positively with pack-years of smoking (r=0.563, p=0.045) and fibrinogen (r=0.431, p=0.040), but not with low-density lipoprotein cholesterol (r=0.202, 0.368). There were no other genotype-associated differences with regard to demographic and clinical variable between carriers and non-carriers, including myocardial infarction (56.5% vs 47.9%, p=0.511), peripheral artery disease (21.7% vs 15.1%, p=0.377) and cerebrovascular events (13.0% vs 6.7%, p=0.389). Conclusions To our knowledge, this is the first report on the prevalence of LPA rs3798220 variant in patients with advanced CAD following CABG surgery under 65 years of age. We showed a relatively high (10.7%) percentage of c.5673G allele carriers who have ten times higher Lp(a) levels compared to the wild type, however, its impact on cardiovascular events requires further studies.

Effect of LPA gene on CAD risk among diabetic patients

Abstract Introduction Previous research reported that the LPA gene is a strong and independent predictor of CAD in non-diabetic patients but not in patients with type 2 diabetes mellitus (T2DM). These results suggest that the LPA gene might contribute less to CAD risk in patients with T2DM than in the general population. Objective Investigate, in our population, the association between the LPA gene variant rs3798220 T>C and CAD risk among the total, diabetic and non-diabetic populations. Methods 3161 individuals (1724 coronary patients and 1437 controls) were genotyped for LPA rs3798220 T>C. This variant has a MAF <2%; hence the risk homozygous CC is a rare genotype, and we used the heterozygous CT in our analysis. Bivariate and multivariate logistic regression evaluated LPA heterozygous genotype (CT) and CAD risk in the whole population, in the group with T2DM (n=782) and without T2DM (n=2379). The multivariate model was adjusted to the main traditional risk factors for CAD. Results After multivariate analysis, LPA CT remained a strong and independent predictor of CAD risk in the whole and non-diabetic populations (OR=2.12; 95%CI: 1.43-3.14; p<0.0001 and OR=2.56; 95%CI: 1.64-4.00; p<0.0001, respectively). However, this association was less pronounced in the diabetic population (OR= 1.12; 95%CI: 0.47-2.65; p=0.799). Conclusions Our results show that the effect of the homozygous LPA genotype on CAD risk among the diabetic population might differ from that in non-diabetics, with less impact on diabetic patients. Many aspects of the genetic regulation of Lp(a) in diabetics are not fully understood, and other genetic and environmental factors may be crucial to CAD risk in diabetes, such as those linked to insulin resistance and hyperglycemia.

Association of Genetic Polymorphisms with Abdominal Aortic Aneurysm in the Processes of Apoptosis, Inflammation, and Cholesterol Metabolism.

Background and Objectives: This study aims to identify the minor allele of the single nucleotide polymorphisms (SNPs) DAB2IP rs7025486, IL6R rs2228145, CDKN2BAS rs10757278, LPA rs3798220, LRP1 rs1466535, and SORT1 rs599839 in order to assess the risk of abdominal aortic aneurysm (AAA) formation and define the linkage among these SNPs. Materials and Methods: A case-control study with AAA patients (AAA group) and non-AAA controls (control group) was carried out in a study population. DNA was isolated from whole blood samples; the SNPs were amplified using PCR and sequenced. Results: In the AAA group of 148 patients, 87.2% of the patients were male, 64.2% had a history of smoking, and 18.2% had relatives with AAA. The mean ± SD of age, BMI, and aneurysmal diameter in the AAA group were 74.8 ± 8.3 years, 27.6 ± 4.6 kg/m2, and 56.2 ± 11.8 mm, respectively. In comparison with 50 non-AAA patients, there was a significantly elevated presence of the SNPs DAB2IP rs7025486[A], CDKN2BAS rs10757278[G], and SORT1 rs599839[G] in the AAA group (p-values 0.040, 0.024, 0.035, respectively), while LPA rs3798220[C] was significantly higher in the control group (p = 0.049). A haplotype investigation showed that the SNPs DAB2IP, CDKN2BAS, and IL6R rs2228145[C] were significantly elevated in the AAA group (p = 0.037, 0.037, and 0.046) with minor allele frequencies (MAF) of 25.5%, 10.6%, and 15.4%, respectively. Only DAB2IP and CDKN2BAS showed significantly higher occurrences of a mutation (p = 0.028 and 0.047). Except for LPA, all SNPs were associated with a large aortic diameter in AAA (p < 0.001). Linkage disequilibrium detection showed that LPA to DAB2IP, to IL6R, to CDKN2BAS, and to LRP1 rs1466535[T] had D' values of 70.9%, 80.4%, 100%, and 100%, respectively. IL6R to LRP1 and to SORT1 had values for the coefficient of determination (r2) of 3.9% and 2.2%, respectively. Conclusions: In the investigated study population, the SNPs CDKN2BAS rs10757278, LPA rs3798220, SORT1 rs599839, DAB2IP rs7025486, and IL6R rs2228145 were associated with the development of abdominal aortic aneurysms. Individuals with risk factors for atherosclerosis and/or a family history of AAA should be evaluated using genetic analysis.

IL6 gene polymorphism association with calcific aortic valve stenosis and influence on serum levels of interleukin-6.

Aortic valve stenosis is the most frequent valve disease in developed countries and its prevalence will increase with population aging. There is still no pharmaceutical treatment nor biomarker to determine the susceptibility to develop aortic stenosis. Therefore, we analyzed the association of polymorphisms in risk loci with calcific aortic stenosis. Patients with aortic valve disease were genotyped for PALMD rs6702619, LPA rs10455872, and IL6 rs1800795 polymorphisms and circulating levels of interleukin-6 (IL-6) were measured. Calcium content of leaflets obtained in valve replacement surgeries was determined by micro-computed tomography. In the genotyping of 578 individuals, we found significant association between PALMD and IL6 polymorphisms and aortic stenosis in patients with tricuspid aortic valve, independently of other potentially confounding variables such as age and dyslipidemia. There was no association of these polymorphisms with valve calcium content, but this value correlated with the mean aortic pressure gradient (r = 0.44; P < 0.001). The CC genotype of IL6 polymorphism was associated with higher levels of serum IL-6 compared to other genotypes (23.5 vs. 10.5 pg/ml, respectively; P = 0.029). Therefore, patients carrying the CC genotype of IL6 rs1800795 polymorphism present higher levels of circulating IL-6 and this could contribute to the severity of the aortic valve stenosis. Our results agree with the identification of IL6 as a locus risk for stenosis and also with the intervention of this cytokine in aortic valve calcification. A more exhaustive follow-up of those patients carrying risk genotypes is therefore recommended.

Impact of genetic information on coronary disease risk in Madeira: The GENEMACOR study

IntroductionCoronary artery disease (CAD), characterized by an atherogenic process in the coronary arteries, is one of the leading causes of death in Madeira. The GENEMACOR (GENEs in MAdeira and CORonary Disease) study sought to investigate the main risk factors – environmental and genetic – and estimate whether a genetic risk score (GRS) improves CAD prediction, discrimination and reclassification. MethodsTraditional risk factors and 33 CAD genetic variants were considered in a case–control study with 3139 individuals (1723 patients and 1416 controls). The multivariate analysis assessed the likelihood of CAD. A multiplicative GRS (mGRS) was created, and two models (with and without mGRS) were prepared. Two areas under receiver operating characteristic curve (area under curve (AUC)) were analyzed and compared to discriminate CAD likelihood. Net reclassification improvement (NRI) and integrated discrimination index (IDI) were used to reclassify the population. ResultsAll traditional risk factors were strong and independent predictors of CAD, with smoking being the most significant (OR 3.25; p<0.0001). LPA rs3798220 showed a higher CAD likelihood (odds ratio 1.45; p<0.0001). Individuals in the fourth mGRS quartile had an increased CAD probability of 136% (p<0.0001). A traditional risk factor-based model estimated an AUC of 0.73, rising to 0.75 after mGRS inclusion (p<0.0001), revealing a better fit. Continuous NRI better reclassified 28.1% of the population, and categorical NRI mainly improved the reclassification of the intermediate risk group. ConclusionsCAD likelihood was influenced by traditional risk factors and genetic variants. Incorporating GRS into the traditional model improved CAD predictive capacity, discrimination and reclassification. These approaches may provide helpful diagnostic and therapeutic advances, especially in the intermediate risk group.

Immune Response and Lipid Metabolism Gene Polymorphisms Are Associated with the Risk of Obesity in Middle-Aged and Elderly Patients.

More than two billion people around the world are overweight or obese. Even in apparently healthy people, obesity has a potent effect on their quality of life. Experimental data indicate the role of infectious agents in systemic inflammation, revealing a correlation between the dietary habits of people with obesity and the level of systemic inflammation mediators, serum lipid concentration, and hormonal and immune status. This study aimed to determine the association of immune response and lipid metabolism gene polymorphisms with the risk of obesity. This study included 560 Caucasian participants living in Western Siberia (Russian Federation). A total of 52 polymorphic sites in 20 genes were analyzed using the 5′ TaqMan nuclease assay. Four risk-associated polymorphic variants were discovered—two variants in immune response genes (IL6R rs2229238, OR = 1.92, 95% CI = 1.36–2.7, p = 0.0002 in the dominant model; IL18 rs1946518, OR = 1.45, 95% CI = 1.03–2.04, p = 0.033 in the over-dominant model) and two variants in lipid metabolism genes (LPA rs10455872, OR = 1.86, 95% CI = 1.07–3.21, p = 0.026 in the log-additive model; LEPR rs1137100, OR = 2.88, 95% CI = 1.52–5.46, p = 0.001 in the recessive model). Thus, polymorphisms in immune response and lipid metabolism genes are potentially associated with the modification of obesity risk in the Caucasian population.

Elevated lipoprotein(a) in mitral and aortic valve calcification and disease: The Copenhagen General Population Study

Background and aimsWe tested the hypotheses (i) that elevated lipoprotein(a) is causally associated with both mitral and aortic valve calcification and disease, and (ii) that aortic valve calcification mediates the effect of elevated lipoprotein(a) on aortic valve stenosis. MethodsFrom the Copenhagen General Population study, we included 12,006 individuals who underwent cardiac computed tomography to measure mitral and aortic valve calcification and 85,884 to examine risk of heart valve disease. Participants had information on plasma lipoprotein(a) and genetic instruments associated with plasma lipoprotein(a) to investigate potential causality. ResultsAt age 70–79 years, 29% and 54% had mitral and aortic valve calcification, respectively. For 10-fold higher lipoprotein(a) levels, multifactorially adjusted odds ratios for mitral and aortic valve calcification were 1.26 (95% confidence interval: 1.13–1.41) and 1.62 (1.48–1.77). For mitral and aortic valve stenosis, corresponding hazard ratios were 0.93 (95%CI:0.40–2.15, 19 events) and 1.54 (1.38–1.71, 1158 events), respectively. For ≤23 versus ≥36 kringle IV type 2 number of repeats, the age and sex adjusted odds ratios for mitral and aortic valve calcification were 1.53 (1.18–1.99) and 2.23 (1.81–2.76). For carriers versus non-carriers of LPA rs10455872, odds ratios for mitral and aortic valve calcification were 1.33 (1.13–1.57) and 1.86 (1.64–2.13). For aortic valve stenosis, 31% (95%CI:16%–76%) of the effect of lipoprotein(a) was mediated through calcification. ConclusionsElevated lipoprotein(a) was genetically and observationally associated with mitral and aortic valve calcification and aortic valve stenosis. Aortic valve calcification mediated 31% of the effect of elevated lipoprotein(a) on aortic valve stenosis.

Association between lipoprotein(a) (Lp(a)) levels and Lp(a) genetic variants with coronary artery calcification

BackgroundTo examine the association between lipoprotein(a) (Lp(a)) levels, LPA (rs10455872 and rs3798220) and IL1F9 (rs13415097) single nucleotide polymorphisms (SNPs) with coronary artery calcification (CAC), an important predictor for coronary artery disease (CAD).MethodsWe used data from 3799 (mean age ± SD: 59.0 ± 7.7 years, 47.1% men) Heinz Nixdorf Recall study participants. We applied linear regression models to explore the relation between the log-transformed Lp(a) levels and LPA and IL1F9 SNPs with loge (CAC + 1). The association between the SNPs and log-transformed Lp(a) levels was further assessed using linear regression. The models were adjusted for age and sex (Model 1) and additionally for Lp(a) levels (Model 2).ResultsWe observed a statistically significant association between log-transformed Lp(a) levels and CAC (Model 1: beta per log-unit increase in Lp(a) levels = 0.11; 95% confidence interval [95% CI] [0.04; 0.18], p = 0.002). Furthermore, the LPA SNP rs10455872 showed a statistically significant association with CAC (Model 1: beta per allele = 0.37 [0.14; 0.61], p = 0.002). The association between rs10455872 and CAC was attenuated after adjustment for Lp(a) levels (Model 2: beta per allele = 0.26 [− 0.01; 0.53], p = 0.06). Both LPA SNPs also showed a statistically significant association with Lp(a) levels (Model 1: betars10455872 per allele: 1.56 [1.46; 1.65], p < 0.0001 and betars3798220 per allele: 1.51 [1.33; 1.69], p < 0.0001)). The Mendelian randomization analysis showed that Lp(a) is a causal risk factor for CAC (estimate per log-unit increase in Lp(a) levels (95% CI), p: 0.27 [0.11; 0.44], p = 0.001). The IL1F9 SNP did not show any statistically significant association with Lp(a) levels or with CAC.ConclusionsWe provide evidence for the association of LPA rs10455872 with higher levels of Lp(a) and CAC in our study. The results of our study suggest that rs10455872, mediated by Lp(a) levels, might play a role in promoting the development of atherosclerosis leading to cardiovascular disease events.

P6200Effect of LPA gene on CAD risk among diabetic patients

Abstract Introduction Previous research reported that LPA gene is a strong and independent predictor of CAD in non-diabetic patients but not in patients with type 2 diabetes. These results suggest that LPA gene might contribute less to CAD risk in patients with T2DM than in general population. Objective Investigate, in our population, the association between LPA gene CT variant and CAD risk among diabetic patients. Methods 3050 individuals (1619 coronary patients and 1431 controls) were genotyped for LPA rs3798220 TT/CT. Pearson's chi-squared test was applied to evaluate the association between LPA variants and CAD, firstly, in the general population and, secondly, in the group of patients with T2DM (n=735). Multivariate logistic regression was performed with LPA CT variant and 6 traditional risk factors (TRF) (smoking, dyslipidemia, diabetes, hypertension, family history of CAD and physical inactivity) in both general and diabetic population. Results In total population, LPA CT variant was found to be strongly and significantly associated with CAD with an OR of 2.32 (95% CI: 1.56–3.45; p&lt;0.0001). However, this association was less pronounced in the diabetic population with a CAD risk of 1.38 (95% CI: 0.56–3.43) without statistical significance (p=0.485). In the presence of 6 major TRF, multivariate analysis showed that LPA CT remained a strong and independent predictor of CAD risk (OR= 2.34; 95% CI: 1.52–3.62; p&lt;0.0001). In diabetic population, LPA was no longer an independent predictor for CAD by multivariate analysis. Conclusions Our results show that the effect of LPA gene on CAD risk among diabetic patients might be different from that in the general population. Diabetes status is such a strong risk factor that may attenuate the genetic effects of LPA on CAD risk. This may indicate a complex role of Lp (a) and diabetes interaction in cardiometabolic diseases.

Elevated Lipoprotein(a) and Risk of Ischemic Stroke

BackgroundHigh lipoprotein(a) is associated with increased risk of myocardial infarction and aortic valve stenosis. Previous studies have examined the association of lipoprotein(a) and risk of stroke; however, the results are conflicting. ObjectivesThe purpose of this study was to test if high lipoprotein(a) is associated with high risk of ischemic stroke observationally and causally from human genetics. MethodsThe study included 49,699 individuals from the Copenhagen General Population Study and 10,813 individuals from the Copenhagen City Heart Study with measurements of plasma lipoprotein(a), LPA kringle-IV type 2 number of repeats, and LPA rs10455872. The endpoint of ischemic stroke was ascertained from Danish national health registries and validated by medical doctors. ResultsCompared with individuals with lipoprotein(a) levels <10 mg/dl (<18 nmol/l: first to 50th percentile), the multivariable-adjusted hazard ratio for ischemic stroke was 1.60 (95% confidence interval [CI]:1.24 to 2.05) for individuals with lipoprotein(a) levels >93mg/dl (>199 nmol/L: 96th to 100th percentile). In observational analyses for a 50 mg/dl (105 nmol/l) higher lipoprotein(a) level the age- and sex-adjusted hazard ratio for ischemic stroke was 1.20 (95% CI: 1.13 to 1.28), while the corresponding age- and sex-adjusted genetic causal risk ratio for KIV-2 number of repeats was 1.20 (95% CI: 1.02 to 1.43) and for rs10455872 was 1.27 (95% CI: 1.06 to 1.51). The highest absolute 10-year risk of ischemic stroke was 17% in active smoking individuals >70 years of age with hypertension and lipoprotein(a) levels >93 mg/dl (>199 nmol/l: 96th to 100th percentile). In the Copenhagen City Heart Study, risk estimates for high levels of lipoprotein(a) were in the same direction but did not reach statistical significance. ConclusionsIn a large contemporary general population study, high plasma levels of lipoprotein(a) were associated with increased risk of ischemic stroke both observationally and causally from human genetics.

High lipoprotein(a) and high risk of mortality.

Several lipoprotein(a)-lowering therapies are currently being developed with the long-term goal of reducing cardiovascular disease and mortality; however, the relationship between lipoprotein(a) and mortality is unclear. We tested the hypothesis that lipoprotein(a) levels are associated with risk of mortality. We studied individuals from two prospective studies of the Danish general population, of which 69764 had information on lipoprotein(a) concentrations, 98810 on LPA kringle-IV type 2 (KIV-2) number of repeats, and 119094 on LPA rs10455872 genotype. Observationally, lipoprotein(a) >93 mg/dL (199 nmol/L; 96th-100th percentiles) vs. <10 mg/dL (18 nmol/L; 1st-50th percentiles) were associated with a hazard ratio of 1.50 (95% confidence interval 1.28-1.76) for cardiovascular mortality and of 1.20 (1.10-1.30) for all-cause mortality. The median survival for individuals with lipoprotein(a) >93 mg/dL (199 nmol/L; 96th-100th percentiles) and ≤93 mg/dL (199 nmol/L; 1st-95th percentiles) were 83.9 and 85.1 years (log rank P = 0.005). For cardiovascular mortality, a 50 mg/dL (105 nmol/L) increase in lipoprotein(a) levels was associated observationally with a hazard ratio of 1.16 (1.09-1.23), and genetically with risk ratios of 1.23 (1.08-1.41) based on LPA KIV2 and of 0.98 (0.88-1.09) based on LPA rs10455872. For all-cause mortality, corresponding values were 1.05 (1.01-1.09), 1.10 (1.04-1.18), and 0.97 (0.92-1.02), respectively. Finally, for a similar cholesterol content increase, lipoprotein(a) was more strongly associated with cardiovascular and all-cause mortality than low-density lipoprotein, implying that the mortality effect of high lipoprotein(a) is above that explained by its cholesterol content. High levels of lipoprotein(a), through corresponding low LPA KIV-2 number of repeats rather than through high cholesterol content were associated with high risk of mortality. These findings are novel.

Effect of Coronary Artery Disease risk SNPs on serum cytokine levels and cytokine imbalance in Premature Coronary Artery Disease

BackgroundPremature Coronary Artery Disease (PCAD) occurs almost a decade earlier in the South Asian population as compared to the West. Inclusion of genetic information can prove to be a robust measure to improve early risk prediction of PCAD. Aim was to estimate the genotypic distribution and risk allele frequencies of 13 Coronary Artery Disease (CAD) risk Single Nucleotide Polymorphisms in loci identified by the CARDIoGRAMplusC4D consortium namely MIA3 rs17465637; 9p21 rs10757274; CXCL12 rs1746048; APOA5 rs662799; APOB rs1042031; LPA rs3798220; LPA 10455872; MRAS rs9818870; LPL rs328; SORT1 rs646776; PCSK9 rs11591147; APOE rs429358; APOE rs7412 in Pakistani PCAD patients and controls. Moreover, the differential serum cytokine levels (IL-18, IL-10, IL-6, TNF-alpha, IL-18:IL-10 & TNF-alpha:IL-10 ratios) with respect to the genotypic distribution of these selected SNPs were determined. Material and methodsThe case-control study was carried out in National University of Sciences and Technology, Islamabad in collaboration with the Cardiovascular Genetics Institute, University College London, UK. Subjects (n=340) with >70% stenosis in at least a single major coronary artery on angiography were taken as PCAD cases along with 310 angiographically verified controls. ELISA was performed for measuring the concentrations of serum IL18, TNFA, IL6 and IL10. Genotyping was done using TAQMAN and KASPar assays. ResultsThe risk allele frequencies (RAF) of APOE rs7412, CXCL12 rs1746048, 9p21 rs10757274, MIA3 rs17465637 and SORT1 rs646776 were significantly higher in the PCAD cases as compared to the controls. APOE rs429358 had the greatest influence among the selected GWAS/CARDIoGRAMplusC4D consortium CAD risk SNPs by significantly altering the serum levels of TNF-alpha, IL-10 and TNF-alpha:IL-10 ratio. It was followed by APOE rs7412 and CXCL12 rs1746048 which significantly altered the serum levels of IL-18; TNF-alpha and IL-18; IL-18:IL-10 ratio respectively. The cytokine imbalance denoted by IL-18:IL-10 was significantly higher in the risk allele carriers MIA3 rs17465637 and CXCL12 rs1746048 while TNF-alpha:IL-10 ratio was significantly raised in the risk allele carriers of APOE rs429358; MRAS rs9818870 and LPL rs328. ConclusionThe association of the selected SNPs with differential serum cytokine levels especially the cytokine imbalance points towards their potential causal role in the immune inflammatory pathogenic pathway of PCAD.

Genetic risk analysis of coronary artery disease in Pakistani subjects using a genetic risk score of 21 variants

Background and aimsConventional coronary artery disease (CAD) risk factors like age, gender, blood lipids, hypertension and smoking have been the basis of CAD risk prediction algorithms, but provide only modest discrimination. Genetic risk score (GRS) may provide improved discrimination over and above conventional risk factors. Here we analyzed the genetic risk of CAD in subjects from Pakistan, using a GRS of 21 variants in 18 genes and examined whether the GRS is associated with blood lipid levels. Methods625 (405 cases and 220 controls) subjects were genotyped for variants, NOS3 rs1799983, SMAD3 rs17228212, APOB rs1042031, LPA rs3798220, LPA rs10455872, SORT1 rs646776, APOE rs429358, GLUL rs10911021, FTO rs9939609, MIA3 rs17465637, CDKN2Ars10757274, DAB2IP rs7025486, CXCL12 rs1746048, ACE rs4341, APOA5 rs662799, CETP rs708272, MRAS rs9818870, LPL rs328, LPL rs1801177, PCSK9 rs11591147 and APOE rs7412 by TaqMan and KASPar allele discrimination techniques. ResultsIndividually, the single SNPs were not associated with CAD except APOB rs1042031 and FTO rs993969 (p = 0.01 and 0.009 respectively). However, the combined GRS of 21 SNPs was significantly higher in cases than controls (19.37 ± 2.56 vs. 18.47 ± 2.45, p = 2.9 × 10−5), and compared to the bottom quintile, CAD risk in the top quintile of the GRS was 2.96 (95% CI 1.71–5.13). Atherogenic blood lipids showed significant positive association with GRS. ConclusionsThe GRS was quantitatively associated with CAD risk and showed association with blood lipid levels, suggesting that the mechanism of these variants is likely to be, in part at least, through creating an atherogenic lipid profile in subjects carrying high numbers of risk alleles.

Low “quotient” Lp(a) Concentration Mediates Autoimmune Activation and Independently Predicts Cardiometabolic Risk

We determined whether U-shaped relationships exist between serum lipoprotein[Lp](a) and cardiometabolic risk. In population-based nondiabetic and diabetic middle-aged adults (n=1 428 and 241, respectively) who had been genotyped for the LPA rs10455872 A>G polymorphism, we adjusted the Lp(a) concentration for the effects of genotype and other covariates. Via sex-specific equations we estimated expected Lp(a) concentration in each participant, and the quotient between observed to expected Lp(a) values was determined. Lp(a) and Lp(a) quotient tertiles served to identify non-linear associations with outcomes. Incident 81 cases of diabetes and 128 of coronary heart disease (CHD) developed at 5.1 years' follow-up. Lp(a) concentration was linearly associated with the LPA genotype, gender, total cholesterol, (inversely) fasting insulin, which together with age formed the variables to derive the equations. In logistic regression for incident diabetes, the low Lp(a) quotient tertile was a predictor (RR 1.95 [95%CI 1.10; 3.47]) alike the low Lp(a) tertile, additively to major confounders. Cox regression models comprising sex, age, LPA genotype, smoking status, systolic pressure and serum HDL-cholesterol disclosed that, compared with the mid-tertile, both low (HR 1.77) and high Lp(a) quotient tertiles significantly predicted incident CHD, especially in women. Elevated cardiometabolic risk is conferred by apparently reduced circulating Lp(a) assays supporting the notion that "low" serum Lp(a), mediating autoimmune activation, is a major determinant of cardiometabolic risk.

LPA rs10455872 polymorphism is associated with coronary lesions in Brazilian patients submitted to coronary angiography.

BackgroundPolymorphisms in the LPA gene were associated with coronary artery disease (CAD). However, there are differences in the allelic frequencies, Lp(a) levels, and significant association with CAD according to ethnic groups. In this scenario, the main aim of this study was to assess the influence of the LPA polymorphisms on coronary lesions in Brazilian patients.Methods1,394 consecutive patients submitted to coronary angiography to study suggestive CAD and twenty coronary segments were scored. Genotyping for the LPA rs10455872 and rs3798220 polymorphisms were performed by high resolution melting analysis.ResultsThe frequencies of the rs10455872 G and rs3798220 C variant alleles were 6.4% and 6.2%, respectively. LPA rs10455872 G variant allele was associated with higher odds ratio of having coronary lesions in an adjusted model (OR = 2.02, 95% CI = 1.10-3.72, p = 0.02). Scores of coronary lesions (extension, severity, and Gensini scores) were significantly different among rs10455872 genotype groups. Coronary lesions was not associated with LPA rs3798220 (OR = 1.09, 95% CI = 0.67-1.76, p = 0.73) and scores of coronary lesions were not different among rs3798220 genotypes.ConclusionsWe confirmed the association of the LPA rs10455872 with CAD in a large sample of Brazilian patients. For the LPA rs3798220, our finding is consistent with studies which showed the lack of this genetic association.

Validation and Quantification of Genetic Determinants of Lipoprotein-a Levels and Predictive Value for Angiographic Coronary Artery Disease

Lipoprotein(a) (Lp[a]) has gained attention as a heritable coronary artery disease (CAD) risk factor and therapeutic target. Two genetic variants in the LPA gene have been reported to influence Lp(a) levels and increase CAD risk. The aim of this study was to prospectively test these variants for their associations with Lp(a) and CAD risk. Participants (n = 1,400) in the Intermountain Heart Collaborative Study Registry who had Lp(a) cholesterol levels determined at coronary angiography were genotyped for rs3798220 and rs1045587 in LPA. Variants were detected by Taqman polymerase chain reaction. Chi-square and linear and logistic regression tests were used as appropriate among genotypes for Lp(a) and angiographic CAD. Age averaged 63 years; 65% were men; and severe CAD was present in 57%, mild CAD in 12%, and no CAD in 31%. Minor allele frequencies were 0.023 for rs3798220 and 0.090 for rs10455872. In multivariate modeling, only rs10455872 (odds ratio [OR] 2.33, 95% confidence interval [CI] 1.67 to 3.33, p = 1.75 × 10⁻⁹) and rs3798220 (OR 1.99, 95% CI 0.99 to 4.00, p = 0.065) contributed to the prediction of elevated Lp(a) cholesterol. Lp(a) cholesterol was weakly associated with CAD (OR 1.17, 95% CI 1.00 to 1.37, p = 0.055). Rs10455872 strongly predicted prevalent CAD (per allele OR 1.43, 95% CI 1.07 to 1.91, p = 0.0172); the effect size for the rare rs3798220 variant was similar (dominant OR 1.47, 95% CI 0.81 to 2.67, p = 0.20), but power was limited to demonstrate significance. The combined genotype explained only a small percentage (≤4%) of variability in Lp(a) cholesterol and prevalence of angiographic CAD. In conclusion, heritable contributions of LPA rs10455872 and rs3798220 to Lp(a) cholesterol levels and to angiographic CAD were prospectively assessed in this study. The percentage of intersubject variability in Lp(a) cholesterol and the percentage of prevalent CAD explained were small.