Haptoglobin Hp2 Variant Promotes Premature Cardiovascular Death in Stroke Survivors

BACKGROUND AND PURPOSE

Haptoglobin (Hp) is an acute phase plasma protein protecting tissues from oxidative damage. It exists in 2 variant alleles (hp1/hp2) giving rise to 3 protein isoforms with different biochemical properties and efficiency to limit oxidative stress. We previously found that hp2 variant is associated with stroke risk in the patients with carotid stenosis and the risk of ischemic cardiovascular events in a general population cohort. This study examined the hypothesis that Hp genotype is associated with general cardiovascular risk in patients with stroke.

METHODS

Hp was genotyped in SAM study (Helsinki Stroke Aging Memory, n=378). A total of 1426 individuals ascertained from a nationally representative cross-sectional health survey served as population controls.

RESULTS

Hp genotype frequencies were 15.6% (hp1-1), 44.2% (hp1-2), and 40.2% (hp2-2) in patients with stroke. During a mean of 7.5-year follow-up after first-ever stroke, hp2 carriers had a substantially higher rate of cardiac deaths (24.5% versus 8.5%; P=0.006) and a trend toward more fatal strokes (23.5% versus 13.6%; P=0.122). The combined risk of ischemic cardiovascular deaths was 2.4-fold higher among hp2 carriers (95% confidence interval, 1.28-4.43) after adjustment for major cardiovascular risk factors.

CONCLUSIONS

Hp2 allele is associated with premature ischemic cardiovascular deaths after first-ever ischemic stroke.

Functional Inducible Nitric Oxide Synthase Gene Variants Associate With Hypertension: A Case-Control Study in a Finnish Population-The TAMRISK Study

Increased inducible nitric oxide synthase (iNOS) activity and expression has been associated with hypertension, but less is known whether the 2 known functional polymorphic sites in the iNOS gene (g.-1026 C/A (rs2779249), g.2087 G/A (rs2297518)) affect susceptibility to hypertension. The objective of this study was to investigate the association between the genetic variants of iNOS and diagnosed hypertension in a Finnish cohort.This study included 320 hypertensive cases and 439 healthy controls. All participants were 50-year-old men and women and the data were collected from the Tampere adult population cardiovascular risk study (TAMRISK). DNA was extracted from buccal swabs and iNOS single nucleotide polymorphisms (SNPs) were analyzed using KASP genotyping PCR. Data analysis was done by logistic regression.At the age of 50 years, the SNP rs2779249 (C/A) associated significantly with hypertension (P = 0.009); specifically, subjects carrying the A-allele had higher risk of hypertension compared to those carrying the CC genotype (OR = 1.47; CI = 1.08-2.01; P = 0.015). In addition, a 15-year follow-up period (35, 40, and 45 years) of the same individuals showed that carriers of the A-allele had more often hypertension in all of the studied age-groups. The highest risk for developing hypertension was obtained among 35-year-old subjects (odds ratio [OR] 3.83; confidence interval [CI] = 1.20-12.27; P = 0.024). Those carrying variant A had also significantly higher readings of both systolic (P = 0.047) and diastolic (P = 0.048) blood pressure during the follow-up. No significant associations between rs2297518 (G/A) variants alone and hypertension were found. However, haplotype analysis of rs2779249 and rs2297518 revealed that individuals having haplotype H3 which combines both A alleles (CA-GA, 19.7% of individuals) was more commonly found in the hypertensive group than in the normotensive group (OR = 2.01; CI = 1.29-3.12; P = 0.002).In conclusion, there was a significant association between iNOS genetic variant (rs2779249) and hypertension in the genetically homogenous Finnish population. Those who carried the rare A-allele of the gene had higher risk for hypertension already at the age of 35 years.

Effects of smoking on outcomes after acute atherothrombotic stroke in Japanese men

BACKGROUND

The effects of smoking on clinical outcomes following acute stroke remain controversial.

METHODS

We evaluated the influence of smoking on 90-day outcomes after acute atherothrombotic stroke in 292 Japanese men extracted from the database of the Edaravone and Argatroban Stroke Therapy for Acute Ischemic Stroke randomized parallel-group trial that tested the safety and efficacy of edaravone and argatroban therapy in 814 patients in 2004-2008. Smokers were matched with non-smokers of the same age for identical age distribution in the smoker and non-smoker groups. Poor 90-day outcomes (defined as death, Barthel index<60, or modified Rankin score>3) were evaluated using a logistic regression model. Significant variables (P<0.05) in univariate analysis were further evaluated by multivariate logistic regression analysis using a forward-selection method.

RESULTS

Body temperature, age, National Institute of Health Stroke Scale score at admission, systolic blood pressure, and smoking status were selected in the final model. Smokers had significantly increased odds of poor 90-day functional outcomes independent of other statistically significant predictor variables (adjusted odds ratio, 2.28; 95% confidence interval, 1.15-4.55; P=0.019).

CONCLUSIONS

In Japanese men, smoking leads to poor functional outcomes at 3 months after acute atherothrombotic stroke.

Gene-smoking interactions in multiple Rho-GTPase pathway genes in an early-onset coronary artery disease cohort

We performed a gene-smoking interaction analysis using families from an early-onset coronary artery disease cohort (GENECARD). This analysis was focused on validating and expanding results from previous studies implicating single nucleotide polymorphisms (SNPs) on chromosome 3 in smoking-mediated coronary artery disease. We analyzed 430 SNPs on chromosome 3 and identified 16 SNPs that showed a gene-smoking interaction at P < 0.05 using association in the presence of linkage--ordered subset analysis, a method that uses permutations of the data to empirically estimate the strength of the association signal. Seven of the 16 SNPs were in the Rho-GTPase pathway indicating a 1.87-fold enrichment for this pathway. A meta-analysis of gene-smoking interactions in three independent studies revealed that rs9289231 in KALRN had a Fisher's combined P value of 0.0017 for the interaction with smoking. In a gene-based meta-analysis KALRN had a P value of 0.026. Finally, a pathway-based analysis of the association results using WebGestalt revealed several enriched pathways including the regulation of the actin cytoskeleton pathway as defined by the Kyoto Encyclopedia of Genes and Genomes.

Educational history is an independent predictor of cognitive deficits and long-term survival in postacute patients with mild to moderate ischemic stroke

BACKGROUND AND PURPOSE

Poststroke cognitive decline and white matter lesions (WML) are related to poor poststroke survival. Whether cognitive reserve as reflected by educational history associates with cognitive decline, recurrent strokes, and poststroke mortality independent of WML is not known.

METHODS

A total of 486 consecutive acute mild/moderate ischemic stroke patients subjected to comprehensive neuropsychological assessment (n=409) and magnetic resonance imaging (n=395) 3 months poststroke were included in the study and followed-up for up to 12 years. Odds ratios (OR) for logistic and hazard ratios for Cox regression analyses are reported (OR and hazard ratio≤1 indicates a beneficial effect).

RESULTS

Long educational history (per tertile) was associated with lower frequency of executive dysfunction in models adjusted for age, sex, marital status, and stroke severity (OR, 0.75; P<0.05) but not when adding WML as a covariate. In contrast, educational history was independently associated with less memory impairment (OR, 0.67; P<0.01), aphasia (OR, 0.69; P<0.05), visuospatial and constructive deficits (OR, 0.70; P<0.05), Mini-Mental State Examination score<25 (OR, 0.53; P<0.0001), and dementia (OR, 0.66; P<0.01). In Cox regression analysis, educational history was not associated with recurrent strokes, but it associated independently with favorable poststroke survival (hazard ratio, 0.86; P<0.05).

CONCLUSIONS

Long educational history associates with less poststroke cognitive deficits, dementia, and favorable long-term survival independent of age, gender, marital status, stroke severity, and WML in patients with mild/moderate ischemic stroke. This supports the hypothesis that educational history as a proxy indicator of cognitive reserve protects against deficits induced by acute stroke.