Common variants in the CRP gene in relation to longevity and cause-specific mortality in older adults: The Cardiovascular Health Study

Common polymorphisms in the CRP gene are associated with plasma CRP levels in population-based studies, but associations with age-related events are uncertain. A previous study of CRP haplotypes in older adults was broadened to include longevity and cause-specific mortality (all-cause, non-cardiovascular (nonCV), and cardiovascular (CV)). Common haplotypes were inferred from four tagSNPs in 4512 whites and five tagSNPs in 812 blacks from the Cardiovascular Health Study, a longitudinal cohort of adults over age 65. Exploratory analyses addressed early versus late mortality. CRP haplotypes were not associated with all-cause mortality or longevity overall in either population, but associations with all-cause mortality differed during early and late periods. In blacks, the haplotype tagged by 3872A (rs1205) was associated with increased risk of nonCV mortality, relative to other haplotypes (adjusted hazard ratio for each additional copy: 1.42, 95% CI: 1.07, 1.87). Relative to other haplotypes, this haplotype was associated with decreased risk of early but not decreased risk of late CV mortality in blacks; among whites, a haplotype tagged by 2667C (rs1800947) gave similar but nonsignificant findings. If confirmed, CRP genetic variants may be weakly associated with CV and nonCV mortality in older adults, particularly in self-identified blacks

Gene-Centric Meta-Analysis of Lipid Traits in African, East Asian and Hispanic Populations

Meta-analyses of European populations has successfully identified genetic variants in over 100 loci associated with lipid levels, but our knowledge in other ethnicities remains limited. To address this, we performed dense genotyping of ∼2,000 candidate genes in 7,657 African Americans, 1,315 Hispanics and 841 East Asians, using the IBC array, a custom ∼50,000 SNP genotyping array. Meta-analyses confirmed 16 lipid loci previously established in European populations at genome-wide significance level, and found multiple independent association signals within these lipid loci. Initial discovery and in silico follow-up in 7,000 additional African American samples, confirmed two novel loci: rs5030359 within ICAM1 is associated with total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) $(p = 8.8×10^{−7} and p = 1.5×10^{−6}$ respectively) and a nonsense mutation rs3211938 within CD36 is associated with high-density lipoprotein cholesterol (HDL-C) levels $(p = 13.5×10^{−12})$. The rs3211938-G allele, which is nearly absent in European and Asian populations, has been previously found to be associated with CD36 deficiency and shows a signature of selection in Africans and African Americans. Finally, we have evaluated the effect of SNPs established in European populations on lipid levels in multi-ethnic populations and show that most known lipid association signals span across ethnicities. However, differences between populations, especially differences in allele frequency, can be leveraged to identify novel signals, as shown by the discovery of ICAM1 and CD36 in the current report

Measuring and using admixture to study the genetics of complex diseases

Abstract Admixture is an important evolutionary force that can and should be used in efforts to apply genomic data and technology to the study of complex disease genetics. Admixture linkage disequilibrium (ALD) is created by the process of admixture and, in recently admixed populations, extends for substantial distances (of the order of 10 to 20 cM). The amount of ALD generated depends on the level of admixture, ancestry information content of markers and the admixture dynamics of the population, and thus influences admixture mapping (AM). The authors discuss different models of admixture and how these can have an impact on the success of AM studies. Selection of markers is important, since markers informative for parental population ancestry are required and these are uncommon. Rarely does the process of admixture result in a population that is uniform for individual admixture levels, but instead there is substantial population stratification. This stratification can be understood as variation in individual admixtures and can be both a source of statistical power for ancestry-phenotype correlation studies as well as a confounder in causing false-positives in gene association studies. Methods to detect and control for stratification in case/control and AM studies are reviewed, along with recent studies showing individual ancestry-phenotype correlations. Using skin pigmentation as a model phenotype, implications of AM in complex disease gene mapping studies are discussed. Finally, the article discusses some limitations of this approach that should be considered when designing an effective AM study.</p

Oleander Stem and Root Standardized Extracts Mitigate Acute Hyperglycaemia by Limiting Systemic Oxidative Stress Response in Diabetic Mice

The extracts of different parts of Nerium oleander L. are used as antidiabetic remedy in the traditional medicinal systems of different parts of the world. Despite these uses in ethnomedicinal system, the antihyperglycemic potentials of oleander stem (NOSE) and root (NORE) extracts have not been pharmacologically evaluated. Therefore, we aimed at evaluating the antidiabetic ethnomedicinal claims of NOSE and NORE, primarily focusing on glucose homeostasis and associated metabolic implications. Alloxan-treated mice with hyperglycaemia (blood glucose >200 mg/dL) were treated with oleander 70% hydromethanolic extracts (200 mg/kg) for 20 consecutive days, and the results were compared with positive control glibenclamide. Blood glucose level was 52–65% lowered (P0.05) changes in insulin sensitivity throughout the treatments. Improved serum insulin remained associated with lowered glucose level (rP = −0.847 and −0.772; P<0.01). Markers of hyperglycaemia-related hepatic glycogen, glycated haemoglobin (HbA1c), hyperlipidaemia, hepatic injury, and diabetic nephropathy were normalized as well. Improvement of systemic intrinsic antioxidant enzymes (catalase and peroxidase) were correlated (rP = −0.952 to −0.773; P<0.01) with lower lipid peroxidation by-product malondialdehyde (MDA) in the circulation. Principal component analysis coupled with hierarchical cluster analysis represented shift in metabolic homeostasis in diabetic mice, which was further normalized by oleander and glibenclamide treatment. Additionally, molecular docking studies of the phenolic acids measured by HPLC with intracellular cytoprotective transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) revealed strong molecular interactions. The results collectively support the ethnomedicine antidiabetic claims of oleander stem and root and suggest that the oleander mediated elevation of systemic antioxidant status is likely responsible for the improved glycaemic control

A functional SNP in the promoter of the SERPINH1 gene increases risk of preterm premature rupture of membranes in African Americans

Prematurity is more prevalent in African Americans than in European Americans. We investigated the contribution of a functional SNP in the promoter of the SERPINH1 gene, enriched among those of African ancestry, to preterm premature rupture of membranes (PPROM), the leading identifiable cause of preterm birth. SERPINH1 encodes heat-shock protein 47, a chaperone essential for collagen synthesis. The SERPINH1 656 minor T allele had a greater frequency in African populations and African Americans than in European Americans (12.4% vs. 4.1%). The 656 T allele displayed significantly reduced promoter activity compared to the major 656 C allele in amnion fibroblasts, which lay down the fibrillar collagen that gives tensile strength to the amnion. An initial case-control study demonstrated that the 656 T allele is significantly more frequent in African-American neonates (P < 0.0009) born from pregnancies complicated by PPROM compared with controls (odds ratio of 3.22, 95% confidence interval 1.50, 7.22). There was no significant difference in ancestry among cases and controls using a dihybrid model based on 29 ancestry-informative markers. Adjusting the results of the case-control study for admixture still yielded a statistically significant association between the 656 T allele and PPROM (P < 0.002). A follow-up case-control study gave similar results. The combined case-control findings showed a highly significant (P < 0.0000045) association between the 656 T allele and PPROM. The SERPINH1 656 T allele is the first example of an ancestry-informative marker associated with preterm birth in African Americans.https://www.pnas.org/content/103/36/1346