@article {1126, title = {Association of genetic variation in serum amyloid-A with cardiovascular disease and interactions with IL6, IL1RN, IL1beta and TNF genes in the Cardiovascular Health Study.}, journal = {J Atheroscler Thromb}, volume = {16}, year = {2009}, month = {2009 Aug}, pages = {419-30}, abstract = {

AIM: Since inflammation is an important contributor to atherosclerosis, gene variants mediating inflammation are of interest. We investigated gene variants in acute phase serum amyloid-A (SAA), a sensitive indicator of inflammatory activity, and their associations with cardiovascular disease (CVD) and HDL cholesterol. Interaction of the SAA genes with genetic variants of their regulators, IL-1, IL-6 and TNF-alpha in influencing CVD was also explored.

METHODS: SNPs characterizing common variation in the SAA1 and SAA2 genes were genotyped in European-(EA) and African-American (AA) participants (n=3969 and n=719) of the Cardiovascular Health Study. Using linear and Cox proportional hazards regression, we assessed associations of SNPs with baseline carotid artery intima-media thickness (cIMT) and risk of incident myocardial infarction, ischemic stroke, total CVD events or mortality during 14 years of follow-up.

RESULTS: No associations between SAA SNPs and outcomes were observed in EA, with the exception of total CVD events; each rs4638289 minor allele was associated with an increased risk in obese individuals, HR=1.2 (95\%CI: 0.981.4; p=0.086) and decreased risk among non-obese, HR=0.9 (95\%CI: 0.80.99; p=0.026). In AA, we observed modest associations between SAA SNPs and cIMT, potentially modified by HDL. SAA SNPs were also associated with lower HDL in EA and AA. Suggestive gene-gene interaction findings for cIMT in AA and CVD mortality in EA were not significant in subsequent model selection tests.

CONCLUSION: Associations of SAA SNPs with cIMT, HDL and total CVD events were identified, unadjusted for multiple testing. These findings should be regarded as hypothesis-generating until confirmed by other studies.

}, keywords = {Aged, Cardiovascular Diseases, Cholesterol, HDL, Cytokines, Female, Gene Regulatory Networks, Humans, Inflammation Mediators, Interleukin 1 Receptor Antagonist Protein, Interleukin-1beta, Interleukin-6, Male, Polymorphism, Single Nucleotide, Proportional Hazards Models, Serum Amyloid A Protein, Tumor Necrosis Factor-alpha, Tunica Intima}, issn = {1880-3873}, author = {Carty, Cara L and Heagerty, Patrick and Heckbert, Susan R and Enquobahrie, Daniel A and Jarvik, Gail P and Davis, Scott and Tracy, Russell P and Reiner, Alexander P} } @article {1158, title = {Interaction between fibrinogen and IL-6 genetic variants and associations with cardiovascular disease risk in the Cardiovascular Health Study.}, journal = {Ann Hum Genet}, volume = {74}, year = {2010}, month = {2010 Jan}, pages = {1-10}, abstract = {

The inflammatory cytokine interleukin-6 (IL-6) is a main regulator of fibrinogen synthesis, though its interaction with fibrinogen genes (FGA, FGB, FGG) and subsequent impact on cardiovascular disease (CVD) risk is not well-studied. We investigated joint associations of fibrinogen and IL6 tagSNPs with fibrinogen concentrations, carotid intima-media thickness, and myocardial infarction or ischemic stroke in 3900 European-American Cardiovascular Health Study participants. To identify combinations of genetic main effects and interactions associated with outcomes, we used logic regression. We also evaluated whether the relationship between fibrinogen SNPs and fibrinogen level varied by IL-6 level using linear regression models with multiplicative interaction terms. Combinations of fibrinogen and IL6 SNPs were significantly associated with fibrinogen level (p < 0.005), but not with other outcomes. Fibrinogen levels were higher in individuals having FGB1437 (rs1800790) and lacking FGA6534 (rs6050) minor alleles; these SNPs interacted with IL6 rs1800796 to influence fibrinogen level. Marginally significant (p= 0.03) interactions between IL-6 level and FGA and FGG promoter SNPs associated with fibrinogen levels were detected. We identified potential gene-gene interactions influencing fibrinogen levels. Although IL-6 responsive binding sites are present in fibrinogen gene promoter regions, we did not find strong evidence of interaction between fibrinogen SNPs and IL6 SNPs or levels influencing CVD.

}, keywords = {Aged, Cardiovascular Diseases, Carotid Arteries, Female, Fibrinogen, Genetic Predisposition to Disease, Genetic Variation, Humans, Interleukin-6, Male, Models, Biological, Myocardial Infarction, Polymorphism, Single Nucleotide, Risk, Stroke}, issn = {1469-1809}, doi = {10.1111/j.1469-1809.2009.00551.x}, author = {Carty, Cara L and Heagerty, Patrick and Heckbert, Susan R and Jarvik, Gail P and Lange, Leslie A and Cushman, Mary and Tracy, Russell P and Reiner, Alexander P} }