@article {1003, title = {Apolipoprotein E gene and retinal microvascular signs in older people: the Cardiovascular Health Study.}, journal = {Mol Vis}, volume = {13}, year = {2007}, month = {2007 Nov 12}, pages = {2105-11}, abstract = {

PURPOSE: To examine the association between apolipoprotein E (APOE) gene polymorphism and retinal microvascular signs in an older population.

METHODS: Retinal photographs were taken of 2,152 participants (1,831 whites, and 321 African-Americans), aged 69-96 years, who were participating in a population-based study of four United States communities. We used standardized protocols to assess photographs for the presence of retinal microvascular signs (retinopathy, arterio-venous nicking, and focal arteriolar narrowing) and a computer-assisted method to measure retinal vessel diameters. We analyzed DNA extracted from blood samples of participants for common allelic variants of the APOE gene.

RESULTS: After adjusting for age, gender, systolic blood pressure, smoking, total serum cholesterol, and other risk factors, we found white participants carrying the epsilon2 and epsilon4 alleles were more likely to have arterio-venous nicking than the epsilon3/epsilon3 homozygotes, with odds ratio (OR) of 1.70 and confidence interval (CI) 95\% (1.03-2.83) for the epsilon2 carriers and OR 1.74 (95\% CI 1.06-2.84) for the epsilon4 carriers. Among white participants without hypertension, the associations remained significant for the epsilon4 carriers (OR 2.32, 95\% CI 1.18-4.57). Whites, normotensive carriers of the epsilon2 allele had significantly narrower retinal arteriolar diameters (adjusted mean arteriolar diameter of 163.5 mum, 95\% CI 160.1-167.0, p=0.03) compared to the epsilon3/epsilon3 homozygotes (167.8 mum, 95\% CI 166.0-169.6). APOE gene polymorphism was not associated with retinopathy, focal narrowing, or retinal venular diameters in white participants. There were insufficient numbers of African-Americans for separate multivariate analysis.

CONCLUSIONS: This study provides little evidence that the APOE gene polymorphism plays a significant role in the pathogenesis of retinal microvascular changes in the general population. In the older white population, APOE epsilon2 and epsilon4 allele carriers were more likely to have arterio-venous nicking. Other retinal signs, however, were not related to APOE gene polymorphism.

}, keywords = {Aged, Aged, 80 and over, Apolipoprotein E2, Apolipoprotein E4, Apolipoproteins E, European Continental Ancestry Group, Female, Gene Frequency, Genotype, Heterozygote, Homozygote, Humans, Male, Microcirculation, Polymorphism, Genetic, Retinal Diseases, Retinal Vessels}, issn = {1090-0535}, author = {Sun, Cong and Tikellis, Gabriella and Liew, Gerald and Klein, Ronald and Larsen, Emily K Marino and Wong, Tien Y} } @article {6027, title = {Genetic loci for retinal arteriolar microcirculation.}, journal = {PLoS One}, volume = {8}, year = {2013}, month = {2013}, pages = {e65804}, abstract = {

Narrow arterioles in the retina have been shown to predict hypertension as well as other vascular diseases, likely through an increase in the peripheral resistance of the microcirculatory flow. In this study, we performed a genome-wide association study in 18,722 unrelated individuals of European ancestry from the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium and the Blue Mountain Eye Study, to identify genetic determinants associated with variations in retinal arteriolar caliber. Retinal vascular calibers were measured on digitized retinal photographs using a standardized protocol. One variant (rs2194025 on chromosome 5q14 near the myocyte enhancer factor 2C MEF2C gene) was associated with retinal arteriolar caliber in the meta-analysis of the discovery cohorts at genome-wide significance of P-value <5{\texttimes}10(-8). This variant was replicated in an additional 3,939 individuals of European ancestry from the Australian Twins Study and Multi-Ethnic Study of Atherosclerosis (rs2194025, P-value = 2.11{\texttimes}10(-12) in combined meta-analysis of discovery and replication cohorts). In independent studies of modest sample sizes, no significant association was found between this variant and clinical outcomes including coronary artery disease, stroke, myocardial infarction or hypertension. In conclusion, we found one novel loci which underlie genetic variation in microvasculature which may be relevant to vascular disease. The relevance of these findings to clinical outcomes remains to be determined.

}, keywords = {Aged, Aged, 80 and over, Arterioles, Chromosomes, Human, Pair 5, European Continental Ancestry Group, Female, Genetic Loci, Genome-Wide Association Study, Genotype, Humans, Male, MEF2 Transcription Factors, Microcirculation, Middle Aged, Models, Genetic, Retinal Vessels}, issn = {1932-6203}, doi = {10.1371/journal.pone.0065804}, author = {Sim, Xueling and Jensen, Richard A and Ikram, M Kamran and Cotch, Mary Frances and Li, Xiaohui and Macgregor, Stuart and Xie, Jing and Smith, Albert Vernon and Boerwinkle, Eric and Mitchell, Paul and Klein, Ronald and Klein, Barbara E K and Glazer, Nicole L and Lumley, Thomas and McKnight, Barbara and Psaty, Bruce M and de Jong, Paulus T V M and Hofman, Albert and Rivadeneira, Fernando and Uitterlinden, Andr{\'e} G and van Duijn, Cornelia M and Aspelund, Thor and Eiriksdottir, Gudny and Harris, Tamara B and Jonasson, Fridbert and Launer, Lenore J and Attia, John and Baird, Paul N and Harrap, Stephen and Holliday, Elizabeth G and Inouye, Michael and Rochtchina, Elena and Scott, Rodney J and Viswanathan, Ananth and Li, Guo and Smith, Nicholas L and Wiggins, Kerri L and Kuo, Jane Z and Taylor, Kent D and Hewitt, Alex W and Martin, Nicholas G and Montgomery, Grant W and Sun, Cong and Young, Terri L and Mackey, David A and van Zuydam, Natalie R and Doney, Alex S F and Palmer, Colin N A and Morris, Andrew D and Rotter, Jerome I and Tai, E Shyong and Gudnason, Vilmundur and Vingerling, Johannes R and Siscovick, David S and Wang, Jie Jin and Wong, Tien Y} }