Genetic variation in the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) is associated with myocardial infarction in the German population

A potential prognostic prediction model for metastatic osteosarcoma based on bioinformatics analysis

Osteosarcoma (OS) is a malignant primary bone tumor with a high incidence. This study aims to construct a prognostic prediction model by screening the prognostic mRNA of metastatic OS. Data on four eligible expression profiles from the National Center for Biotechnology Information Gene Expression Omnibus repository were obtained based on inclusion criteria and defined as the training set or the validation set. The differentially expressed genres (DEGs) between meta- static and non-metastatic OS samples in the training set were first identified, and DEGs related to prognosis were screened by univariate Cox regression analysis. In total, 107 DEGs related to the prognosis of metastatic OS were identified. Then, 46 DEGs were isolated as the optimized prognostic gene signature, and a metastatic-OS discriminating classifier was constructed, which had a high accuracy in distinguishing metastatic from non-metastatic OS samples. Furthermore, four optimized prognostic gene signatures (ALOX5AP, COL21A1, HLA-DQB1, and LDHB) were further screened, and the prognostic prediction model for metastatic OS was constructed. This model possesses a relatively satisfying prediction ability both in the training set and validation set. The prognostic prediction model that was constructed based on the four prognostic mRNA signatures has a high predictive ability for the prognosis of metastatic OS.

Genetic and Epigenetic Regulation of Lipoxygenase Pathways and Reverse Cholesterol Transport in Atherogenesis

Atherosclerosis is one of the most important medical and social problems of modern society. Atherosclerosis causes a large number of hospitalizations, disability, and mortality. A considerable amount of evidence suggests that inflammation is one of the key links in the pathogenesis of atherosclerosis. Inflammation in the vascular wall has extensive cross-linkages with lipid metabolism, and lipid mediators act as a central link in the regulation of inflammation in the vascular wall. Data on the role of genetics and epigenetic factors in the development of atherosclerosis are of great interest. A growing body of evidence is strengthening the understanding of the significance of gene polymorphism, as well as gene expression dysregulation involved in cross-links between lipid metabolism and the innate immune system. A better understanding of the genetic basis and molecular mechanisms of disease pathogenesis is an important step towards solving the problems of its early diagnosis and treatment.

Expression profiles of long noncoding RNAs and messenger RNAs in the border zone of myocardial infarction in rats

Background

The participation of long noncoding RNAs (lncRNAs) in myocardial infarction has recently been noted. However, their underlying roles in the border zone of myocardial infarction remain unclear. This study uses microarrays to determine the profiles of lncRNAs and mRNAs in the border zone.

Methods

Bioinformatics methods were employed to uncover their underlying roles. Highly dysregulated lncRNAs was further validated via PCR.

Results

Four hundred seven lncRNAs and 752 mRNAs were upregulated, while 132 lncRNAs and 547 mRNAs were downregulated in the border zone of myocardial infarction. A circos graph was constructed to visualize the chromosomal distribution and classification of the dysregulated lncRNAs and mRNAs. The upregulated mRNAs in the border zone were most highly enriched in cytokine activity, binding, cytokine receptor binding and related processes, as ascertained through Go analysis. Pathway analysis of the upregulated mRNAs showed the most significant changes were in the TNF signaling pathway, cytokine–cytokine receptor interaction and chemokine signaling pathway and similar pathways and interactions. An lncRNA–mRNA co-expression network was established to probe into the underlying functions of the 10 most highly dysregulated lncRNAs based on their co-expressed mRNAs. In the co-expression network, we found 16 genes directly involved in myocardial infarction, including Alox5ap, Itgb2 and B4galt1. The lncRNAs AY212271, EF424788 and MRAK088538, among others, might be associated with myocardial infarction. BC166504 is probably a key lncRNA in the border zone of myocardial infarction.

Conclusions

The results may have revealed some aberrantly expressed lncRNAs and mRNAs that contribute to the underlying pathophysiological mechanisms of myocardial infarction.

Genetic variation in the leukotriene pathway is associated with myocardial infarction in the Chinese population

Background

Genetic variation in the genes ALOX5 (arachidonate 5-lipoxygenase), ALOX5AP (arachidonate 5-lipoxygenase-activating protein) and LTA4H (leukotriene A4 hydrolase) has previously been shown to contribute to the risk of MI (myocardial infarction) in Caucasian and African American populations. All genes encode proteins playing a role in the synthesis of the pro-inflammatory leukotriene B mediators, possibly providing a link between MI and inflammation. The aim of the present study was to investigate whether these associations could be confirmed in the study of China MI patients. The study included 401 Han Chinese MI patients and 409 controls. Six tag single nucleotide polymorphisms (SNPs)—ALOX5 rs12762303 and rs12264801, ALOX5AP rs10507391, LTA4H rs2072512, rs2540487 and rs2540477—were selected. SNP genotyping was performed by an improved multiplex ligation detection reaction assay.

Results

The rs2540487 genotype was associated with the risk of MI in overdominant model (P = 0.008). rs12762303 and rs10507391 SNPs were significantly associated with lipid levels in MI patients (P < 0.006–0.008). Several SNPs interacted with alcohol consumption, cigarette smoking, and hypertension to modify TC, TG, LDL-C and CRE levels, and the risk of MI (P < 0.0017 for all). No association between the SNPs of LT pathway and susceptibility to MI was found (P > 0.05 for all).

Conclusions

Taken together, this study provides additional evidence that functional genetic variation of the LT pathway can mediate atherogenic processes and the risk of MI in Chinese.

Weighted Multi-marker Genetic Risk Scores for Incident Coronary Heart Disease among Individuals of African, Latino and East-Asian Ancestry

We examined the clinical utility of two multi-locus genetic risk scores (GRSs) previously validated in Europeans among persons of African (AFR; n = 2,089), Latino (LAT; n = 4,349) and East-Asian (EA; n = 4,804) ancestry. We used data from the GERA cohort (30-79 years old, 68 to 73% female). We utilized two GRSs with 12 and 51 SNPs, respectively, and the Framingham Risk Score (FRS) to estimate 10-year CHD risk. After a median 8.7 years of follow-up, 450 incident CHD events were documented (95 in AFR, 316 in LAT and 39 EA, respectively). In a model adjusting for principal components and risk factors, tertile 3 vs. tertile 1 of GRS_12 was associated with 1.86 (95% CI, 1.15-3.01), 1.52 (95% CI, 1.02-2.25) and 1.19 (95% CI, 0.77-1.83) increased hazard of CHD in AFR, LAT and EA, respectively. Inclusion of the GRSs in models containing the FRS did not increase the C-statistic but resulted in net overall reclassification of 10% of AFR, 7% LAT and EA and in reclassification of 13% of AFR and EA as well as 10% LAT in the intermediate FRS risk subset. Our results support the usefulness of incorporating genetic information into risk assessment for primary prevention among minority subjects in the U.S.

Clinical Utility of Multimarker Genetic Risk Scores for Prediction of Incident Coronary Heart Disease: A Cohort Study Among Over 51 000 Individuals of European Ancestry

BACKGROUND

We evaluated whether including multilocus genetic risk scores (GRSs) into the Framingham Risk Equation improves the predictive capacity, discrimination, and reclassification of asymptomatic individuals with respect to coronary heart disease (CHD) risk.

METHODS AND RESULTS

We performed a cohort study among 51 954 European-ancestry members of a Northern California integrated healthcare system (67% female; mean age 59) free of CHD at baseline (2007-2008). Four GRSs were constructed using between 8 and 51 previously identified genetic variants. After a mean (±SD) follow-up of 5.9 (±1.5) years, 1864 incident CHD events were documented. All GRSs were linearly associated with CHD in a model adjusted by individual risk factors: hazard ratio (95% confidence interval) per SD unit: 1.21 (1.15-1.26) for GRS_8, 1.20 (1.15-1.26) for GRS_12, 1.23 (1.17-1.28) for GRS_36, and 1.23 (1.17-1.28) for GRS_51. Inclusion of the GRSs improved the C statistic (ΔC statistic =0.008 for GRS_8 and GRS_36; 0.007 for GRS_12; and 0.009 for GRS_51; all P<0.001). The net reclassification improvement was 5% for GRS_8, GRS_12, and GRS_36 and 4% for GRS_51 in the entire cohort and was (after correcting for bias) 9% for GRS_8 and GRS_12 and 7% for GRS_36 and GRS_51 when analyzing those classified as intermediate Framingham risk (10%-20%). The number required to treat to prevent 1 CHD after selectively treating with statins up-reclassified subjects on the basis of genetic information was 36 for GRS_8 and GRS_12, 41 for GRS_36, and 43 for GRS_51.

CONCLUSIONS

Our results demonstrate significant and clinically relevant incremental discriminative/predictive capability of 4 multilocus GRSs for incident CHD among subjects of European ancestry.

Targeted deep resequencing of ALOX5 and ALOX5AP in patients with diabetes and association of rare variants with leukotriene pathways

The aim of the present study was to investigate a possible association between the accumulation of rare coding variants in the genes for arachidonate 5-lipoxygenase (ALOX5) and ALOX5-activating protein (ALOX5AP), and corresponding production of leukotrienes (LTs) in patients with type 2 diabetes mellitus (T2DM) receiving acetylsalicylic therapy. Twenty exons and corresponding introns of the selected genes were resequenced in 303 DNA samples from patients with T2DM using pooled polymerase chain reaction amplification and next-generation sequencing, using an Illumina HiSeq 2000 sequencing system. The observed non-synonymous variants were further confirmed by individual genotyping of DNA samples comprising of all individuals from the original discovery pools. The association between the investigated phenotypes was based on LTB4 and LTE4 concentrations, and the accumulation of rare missense variants (genetic burden) in investigated genes was evaluated using statistical collapsing tests. A total of 10 exonic variants were identified for each resequenced gene, including 5 missense and 5 synonymous variants. The rare missense variants did not exhibit statistically significant differences in the accumulation pattern between the patients with low and high LTs concentrations. As the present study only included patients with T2DM, it is unclear whether the absence of observed association between the accumulation of rare missense variants in investigated genes and LT production is associated with diabetic populations only or may also be applied to other populations.

A novel risk haplotype of ALOX5AP gene is associated with ischemic stroke in Chinese Han population

Previous studies have implicated that two at-risk haplotypes (HapA and HapB) of gene-encoding 5-lipoxygenase-activating protein (ALOX5AP) were significantly associated with stroke. The aim of this study was to explore the association between haplotypes of ALOX5AP gene and risk for ischemic stroke (IS) in Chinese Han population. A total of 492 patients with IS and 490 matched control subjects were recruited. Six ALOX5AP SNPs (SG13S377, SG13S114, SG13S41, SG13S89, SG13S32 and SG13S35) were genotyped by SNaPshot minisequence technique. A common genetic variant SG13S114/AA in the ALOX5AP gene was associated with IS in this Chinese cohort (OR = 2.514, 95 % CI = 1.667 ~ 3.790). HapA (TGA) and HapB (AAAG) had no significant difference in the patients (36.3 and 18.5 %, respectively) and controls (37.6 and 16.3 %, respectively) (P = 0.631 and P = 0.375, respectively). But, the frequency of Hap (GAAG) was significantly higher in the patients than that in the controls after Bonferroni's adjustment (P = 0.006). To conclude, SG13S114/AA of the ALOX5AP gene was associated with an increased risk for IS. A novel risk haplotype, Hap (GAAG) was a genetic risk factor for IS in this Chinese population.

Leukotriene A4 hydrolase haplotype, diet and atherosclerosis: a twin study

OBJECTIVE

Atherosclerosis is an inflammatory process resulting from the interaction between genetic and environmental factors. Leukotrienes are inflammatory mediators generated from arachidonic acid, and genetic polymorphisms involved in leukotriene metabolism are implicated in atherosclerosis. The objectives of this study are to examine whether genetic variants in key leukotriene enzymes are associated with atherosclerosis, and whether dietary intake of competing leukotriene substrates modifies the effect of leukotriene variants on atherosclerosis.

METHODS

Atherosclerosis was assessed by common carotid intima-media thickness (IMT) using ultrasound. Sequence variants within arachidonate 5-lipoxygenase activating protein (ALOX5AP) and leukotriene A4 hydrolase (LTA4H) genes were analyzed with 32 single nucleotide polymorphisms (SNPs) in 169 Caucasian twin pairs from the Vietnam Era Twin Registry. The associations between genetic polymorphisms and carotid atherosclerosis, and gene × diet interactions were examined by generalized estimating equation controlling for potential confounders.

RESULTS

A six-SNP haplotype in LTA4H, designated HapE, was significantly associated with carotid IMT after adjusting for known coronary risk factors. Twins carrying HapE had a much lower IMT compared to twins not carrying (695 μm vs. 750 μm, p = 0.0007). Moreover, dietary intake of polyunsaturated fatty acids strongly augmented the cardioprotective effect of HapE among those with this haplotype but not those without, suggesting a haplotype × diet interaction (interaction P(HapE×n-3) = 0.03, P(HapE×n-6) = 0.015).

CONCLUSION

We identified a novel leukotriene haplotype that appears to be protective toward subclinical atherosclerosis. This association is modified by dietary intake of polyunsaturated fatty acids.

Association between arachidonate 5-lipoxygenase-activating protein (ALOX5AP) and lung function in a Korean population

Arachidonate 5-lipoxygenase-activating protein (ALOX5AP) plays a role in the 5-lipoxygenase (LO) pathway, which includes the LTC(4), LTD(4), LTE(4) and LTB(4). These leukotrienes are known causative factors of asthma, allergy, atopy and cardiovascular diseases. ALOX5AP lacks enzyme activity and acts by helping 5-LO function. In this study, healthy and general subjects who live in rural and urban areas of Korea were tested for the association of ALOX5AP polymorphisms with lung function. Lung function was also estimated by calculating the predicted values for forced expiratory volume in one second (FEV(1) _%PRED) and the proportion of the forced vital capacity exhaled in the first second (FEV(1) /FVC_PRED). The linear regression was adjusted for residence area, gender, age, height and smoking status. The analysis revealed associations between FEV(1) and the single-nucleotide polymorphism (SNP) rs9506352 and the haplotype TCAC (permuted P-value < 0.05). The linkage disequilibrium block that included the significant SNPs overlapped with SNPs that were revealed previously to associate with myocardial infarction and asthma and to affect lung function. This study is the first to demonstrate the association between lung function and ALOX5AP polymorphisms in a healthy and general population.

Association of ALOX5AP gene single nucleotide polymorphisms and cerebral infarction in the Han population of northern China

BACKGROUND

To explore the association of ALOX5AP single nucleotide polymorphisms (SNPs) and haplotype with the occurrence of cerebral infarction in the Han population of northern China.

METHODS

Blood samples were collected from 236 patients of Han ancestry with a history of cerebral infarction and 219 healthy subjects of Han ancestry with no history of cerebral infarction or cardiovascular disease. Applied Biosystems(®) TaqMan(®) SNP Genotyping Assays for SNP genotyping were used to determine the genotypes of 7 ALOX5AP SNP alleles (rs4073259, rs4769874, rs9315050, rs9551963, rs10507391, rs9579646, and rs4147064).

RESULTS

One SNP allele (A) of rs4073259 was significantly associated with development of cerebral infarction (P = 0.049). In comparison to control groups, haplotype rs9315050&rs9551963 AAAC [OR (95% CI) = 1.53 (1.02-2.29)], and genotypes rs4147064 CT [OR (95% CI) = 1.872 (1.082-3.241)], and rs9551963 AC [OR (95% CI) = 2.015 (1.165-3.484)] increased the risk of cerebral infarction in patients with hypertension. Genotype rs9579646 GG [OR (95% CI) = 2.926 (1.18-7.251)] increased the risk of, while rs4073259 GG [OR (95% CI) = 0.381 (0.157-0.922)] decreased the risk of cerebral infarction in patients with diabetes.

CONCLUSION

These results suggest the ALOX5AP SNP A allele in rs4073259 and genotype rs9579646 GG, rs9551963 AC, and haplotype rs9315050 & rs9551963 AAAC were associated with an increased risk of ischemic stroke in the Han population, while rs4073259 GG was associated with a decreased risk.

Association of ALOX5AP haplotypes with susceptibility to coronary artery disease in a Chinese Han population

BACKGROUND

The 5-lipoxygenase activating protein (FLAP), encoded by the activating 5-lipoxygenase (ALOX5AP) gene, is a crucial mediator of the biosynthesis of leukotrienes, which have been implicated in atherosclerosis. This study investigates whether ALOX5AP polymorphisms are associated with coronary artery disease (CAD) in a Chinese Han population.

METHODS

The promoter, exons, splice site region and 3'-untranslated region of the ALOX5AP gene were sequenced in 48 subjects. Three polymorphic sites (-1340T/G, +8733T/C, +20616G/C) found through sequencing were evaluated in 656 patients with angiographically proven CAD and 678 controls with normal coronary angiograms using a polymerase chain reaction and restriction fragment length polymorphism assay. Allelic, genotypic linkage disequilibrium and haplotypic association testing were performed using SHEsis and LDA software. Binary logistic regression was used to control for the presence of vascular risk factors.

RESULTS

Seven single nucleotide polymorphisms (SNPs) were found through screening. No significant differences in allele carriers and genotype frequencies of the ALOX5AP polymorphisms were observed between the two groups. However, when the results of the three SNPs were combined, there was a significant association between two of the haplotypes and the risk of CAD. The haplotype GCG had a significantly greater frequency in patients than in controls (P<0.001, OR=1.728, 95%CI=1.375-2.171), and the frequency of haplotype TCG was higher in controls (P<0.001, OR=0.623, 95%CI=0.519-0.748).

CONCLUSION

The data indicate that ALOX5AP gene variation is a genetic factor associated with interindividual differences in CAD risk.

Pathway-based genome-wide association analysis of coronary heart disease identifies biologically important gene sets

Genome-wide association (GWA) studies of complex diseases including coronary heart disease (CHD) challenge investigators attempting to identify relevant genetic variants among hundreds of thousands of markers being tested. A selection strategy based purely on statistical significance will result in many false negative findings after adjustment for multiple testing. Thus, an integrated analysis using information from the learned genetic pathways, molecular functions, and biological processes is desirable. In this study, we applied a customized method, variable set enrichment analysis (VSEA), to the Framingham Heart Study data (404,467 variants, n=6421) to evaluate enrichment of genetic association in 1395 gene sets for their contribution to CHD. We identified 25 gene sets with nominal P<0.01; at least four sets are previously known for their roles in CHD: vascular genesis (GO:0001570), fatty-acid biosynthetic process (GO:0006633), fatty-acid metabolic process (GO:0006631), and glycerolipid metabolic process (GO:0046486). Although the four gene sets include 170 genes, only three of the genes contain a variant ranked among the top 100 in single-variant association tests of the 404,467 variants tested. Significant enrichment for novel gene sets less known for their importance to CHD were also identified: Rac 1 cell-motility signaling pathway (h_rac1 Pathway, P<0.001) and sulfur amino-acid metabolic process (GO:0000096, P<0.001). In summary, we showed that the pathway-based VSEA can help prioritize association signals in GWA studies by identifying biologically plausible targets for downstream searches of genetic variants associated with CHD.

A Promoter polymorphism (rs17222919, -1316T/G) of ALOX5AP is associated with intracerebral hemorrhage in Korean population

To investigate whether single nucleotide polymorphisms (SNPs) of eicosanoid biosynthesis genes are associated with intracerebral hemorrhage (ICH) and ischemic stroke (IS), seven SNPs in the coding or promoter regions were selected: ALOX12 (rs434473, Asn322Ser), ALOX5 (rs2228064, Thr90Thr), ALOX5AP (rs17222919, -1316T/G), PTGES (rs7872802, -404A/G), PTGIS (rs5628, Leu256Leu), PTGS1 (rs3842788, Gln41Gln) and PTGS2 (rs5275, 3'UTR). A total of 398 control subjects and 196 stroke patients (79 ICH and 117 IS) were genotyped by direct sequencing. The rs17222919 SNP was associated with ICH in codominant 1 (P=0.008), dominant (P=0.003) and log-additive (P=0.004) models. Allele frequencies of rs17222919 were different between ICH and controls (P=0.007). However, the seven tested SNPs were not associated with clinical phenotypes (NIHSS, MBI and CRPS) in ICH and IS. These results suggest that the promoter SNP rs17222919 of ALOX5AP may be associated with the development of ICH in Korean population.

Genetic contribution of the leukotriene pathway to coronary artery disease

We evaluated the genetic contribution of the leukotriene (LT) pathway to risk of coronary artery disease (CAD) in 4,512 Caucasian and African American subjects ascertained through elective cardiac evaluation. Of the three previously associated variants, the shorter "3" and "4" alleles of a promoter repeat polymorphism in ALOX5 increased risk of CAD in African Americans (OR = 1.4, 95% CI 1.0-1.9; p = 0.04), whereas a haplotype of LTA4H (HapK) was associated with CAD in Caucasians (OR = 1.2, 95% CI 1.01-1.4; p = 0.03). In Caucasians, first-stage analysis of 254 haplotype-tagging SNPs in 15 LT pathway genes with follow-up of 19 variants in stage 2 revealed an LTA4H SNP (rs2540477) that increased risk of CAD (OR = 1.2, 95% CI 1.1-1.5; p = 0.003) and a PLA2G4A SNP (rs12746200) that decreased risk of CAD (OR = 0.7, 95% CI 0.6-0.9; p = 0.0007). The PLA2G4A rs12746200 variant also decreased risk of experiencing a major adverse cardiac event (MACE = myocardial infarction, stroke, or death) over 3 years of follow-up (HR = 0.7, 95% CI 0.5-0.9; p = 0.01), consistent with its cardioprotective effect. Functional experiments demonstrated that stimulated monocytes from carriers of LTA4H variants HapK or rs2540477 had 50% (p = 0.002) and 33% (p = 0.03) higher LTB(4) production, respectively, compared to non-carriers. These ex vivo results are consistent with LTB(4) being the direct product of the reaction catalyzed by LTA4H and its role in promoting monocyte chemotaxis to sites of inflammation, including the artery wall of atherosclerotic lesions. Taken together, this study provides additional evidence that functional genetic variation of the LT pathway can mediate atherogenic processes and the risk of CAD in humans.

Variants of arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene and risk of coronary heart disease: A meta-analysis

BACKGROUND AND AIMS

Previous studies indicated that the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene polymorphisms are associated with risk of coronary heart disease (CHD). However, other studies have yielded contradictory results. This meta-analysis investigated the relationship between variants of arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene and CHD.

METHODS

We identified all studies published before January 2010 through computer-based searches of PubMed, EMBASE, Google Scholar databases, and CNKI (Chinese National Knowledge Infrastructure). Data were extracted by two authors and pooled odds ratio (OR) and 95% confidence interval (CI) were calculated.

RESULTS

In this meta-analysis, HapA haplotype (rs17222814G-rs10507391T-rs4769874G-rs9551963A) was associated with myocardial infarction (MI) (OR = 1.37, 95% CI: 1.02-1.82). Regarding the HapB haplotype (rs17216473A-rs10507391A- rs9315050A- rs17222842G), there was a significant association with CHD (OR = 1.33, 95% CI: 1.10-1.62). For the rs17222814, rs10507391, rs4769874, rs9551963, rs17216473, rs9315050 and rs9579646 polymorphisms, there were no associations with CHD. For the rs17222842 polymorphism, there was a marginal association with the risk of CHD (OR = 1.17, 95% CI: 1.00-1.36).

CONCLUSIONS

In this meta-analysis, the HapB haplotype and rs1722842 polymorphism in ALOX5AP gene were associated with CHD, and the HapA haplotype was associated with risk of MI. The HapB haplotype may be a predictor to the risk of CHD.

ALOX5AP gene variants show differential association with coronary artery disease in different populations

Coronary artery disease (CAD) is a complex disease with various components, genetic as well as environmental. Previous reports correlating ALOX5AP gene variants and CAD showed conflicting results depending on the population studied. In this study, we examined the contribution of ALOX5AP genetic predisposition to CAD in a group of CAD patients and controls carefully selected from the Lebanese population. We genotyped SNPs for ALOX5AP variants in 289 catheterized patients aged ≤52 years with >50% stenosis in at least one main coronary artery and 227 catheterized control subjects aged 60 years and above with 0% stenosis. Chi-square (χ (2)) tests and logistic regression showed no significant difference in the allele and genotype frequencies between the CAD or myocardial infarction (MI) cases and the healthy controls. Haplotype analysis using PHASE showed that the distribution of the risk haplotypes among cases and controls were not significantly different and had no attributable risk to CAD (P = 1.00 and P = 0.5, respectively) or MI (P = 0.2 and P = 0.5, respectively). Our data revealed that ALOX5AP gene variants are not predictors of CAD risk or MI risk among Lebanese patients.

Polyunsaturated fatty acids and cardiovascular disease: implications for nutrigenetics

Cardiovascular disease (CVD) arises as a result of genetic predisposition in the context of a disease-promoting environment. While several risk factors have been identified for CVD, such as elevated serum lipid levels and hypertension, most of the genes identified thus far do not appear to involve such 'conventional' risk factors. Moreover, the interactions between genes and environment, such as a diet high in certain fats, adds another level of complexity to CVD and renders identification of the underlying genetic factors even more difficult. Polyunsaturated fatty acids (PUFAs), such as the omega-6 and omega-3 fatty acids, which have multiple roles in membrane structure, lipid metabolism, blood clotting, blood pressure, and, in particular, inflammation, have been linked to the reduction in CVD. Linoleic (omega-6) and alpha-linolenic acid (omega-3) are essential fatty acids that can be converted into long-chain PUFAs, such as arachidonic acid (AA) and eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA), respectively. These long-chain PUFAs are metabolized by enzymatically catalyzed systems via cyclooxygenases and lipoxygenases. The 5-lipoxygenase (5-LO)/leukotriene (LT) biosynthesis pathway has been biochemically and genetically associated with CVD traits in mice and humans, particularly in the context of dietary AA and EPA/DHA. In this review, we summarize the biochemical metabolism of omega-3 and omega-6 PUFAs, evaluate the evidence for genetic and nutrigenetic contributions of 5-LO pathway genes to CVD, and discuss the potential of future studies that could identify other gene-dietary interactions between PUFAs and CVD traits.

Variants of the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene and risk of stroke: a HuGE gene-disease association review and meta-analysis

Variants of the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene have been implicated as a risk factor for stroke. However, genetic association studies that have examined the association between ALOX5AP gene variants (HapA haplotype, HapB haplotype, and SG polymorphisms) and stroke have produced conflicting results. Therefore, the authors performed a meta-analysis of all studies with ALOX5AP genotyping (5,194 stroke cases and 4,566 controls). The meta-analysis showed significant heterogeneity among studies (P(Q) = 0.03, I(2) = 63%) and a nonsignificant association between the HapA haplotype (SG13S25G-SG13S114T-SG13S89G-SG13S32A) and stroke risk (random-effects (RE) odds ratio (OR) = 1.13, 95% confidence interval (CI): 0.88, 1.45). Regarding the HapB haplotype (SG13S377A-SG13S114A-SG13S41A-SG13S35G), there was no association with stroke risk (RE OR = 1.03, 95% CI: 0.77, 1.37). The SG13S114, SG13S89, SG13S25, SG13S32, SG13S35, and SG13S42 polymorphisms were not associated with stroke. The SG13S106 and SG13S377 polymorphisms revealed evidence of marginal association (RE OR = 1.23 (95% CI: 1.03, 1.46) and RE OR = 1.25 (95% CI: 1.04, 1.50), respectively). However, cumulative meta-analysis for the HapA haplotype showed a downward trend of odds ratios over time, and recursive cumulative meta-analysis indicated insufficient evidence for claiming or denying an association. Tests for bias revealed no evidence of biases. Rigorous genetic association studies investigating gene-gene-environment interactions may generate more conclusive claims about the genetics of stroke.