Epigenome-Wide Analyses Identify Two Novel Associations With Recurrent Stroke in the Vitamin Intervention for Stroke Prevention Clinical Trial

Abstract

DNA methylation, a well-characterized epigenetic modification that is influenced by both environment and genetic variation, has previously been implicated in a number of complex diseases, including cardiovascular disease and stroke. The goal of this study was to evaluate epigenome-wide associations with recurrent stroke and the folate one-carbon metabolism-related trait, plasma homocysteine (hcy). Differential methylation analyses were performed on 473,864 autosomal CpG loci, using Illumina HumanMethylation 450K array data in 180 ischemic stroke cases from the Vitamin Intervention for Stroke Prevention (VISP) clinical trial. Linear regression was used to assess associations between number of strokes prior to VISP enrollment and measures of hcy with degree of methylation (β-values), while logistic regression was used to evaluate recurrent stroke status and incident recurrent stroke associations. All regression analyses were stratified by race. Two differentially methylated CpG sites exceeded epigenome-wide significance (p ≤ 1.055 × 10−7) for prior number of strokes (PNS) in European Americans. The top locus, cg22812874, was located in the ankyrin repeat and SOCS box containing 10 gene (ASB10; p = 3.4 × 10−9; β = −0.0308; 95% CI = −0.040, −0.002). Methylation locus cg00340919, located in an intron of the tetratricopeptide repeat domain 37 gene, was also statistically significant (TTC37; p = 8.74 × 10−8; β = −0.0517; 95% CI = −0.069, −0.034). An additional 138 CpG sites met our threshold for suggestive significance (p ≤ 5 × 10−5). We evaluated DNA methylation associated with recurrent stroke and hcy phenotypes across the epigenome. Hypermethylation at two CpG sites located in ASB10 and TTC37 was associated with fewer strokes prior to VISP enrollment. Our findings present a foundation for additional epigenome-wide studies, as well as mechanistic studies into epigenetic marks that influence recurrent stroke risk.

Multi-omic analysis of stroke recurrence in African Americans from the Vitamin Intervention for Stroke Prevention (VISP) clinical trial

“…As previously described, Illumina Infinium HumanMethylation450K BeadChip microarrays (Illumina, Inc., San Diego, CA, United States) were used per the manufacturer’s protocol to determine the degree of methylation (β values) for 485,512 methylation loci [ 11 ]. Quality control and quantile normalization was performed, resulting in 473,864 autosomal methylation CpG loci [ 12 – 14 ].…”

Comparison of DNA Methylation Profiles of Hemostatic Genes between Liver Tissue and Peripheral Blood within Individuals

“…With regards to arterial thrombotic diseases, EWASs have identified several CpGs that are differentially methylated in cases with myocardial infarction (MI) or ischemic stroke compared with controls. 11 12 13 14 A large EWAS also identified CpGs showing differential methylation in relation to age-independent cardiovascular risk factors. 15 A methylation risk score, created based on these differentially methylated CpGs, was significantly associated with incident cardiovascular events in the Framingham offspring study, and this association was independent of age, sex, and classical vascular risk factors.…”

“…8,9 In addition to genetic variants, there is increasing evidence for the involvement of epigenetic mechanisms, such as DNA methylation, in many human diseases, 10 and those caused by arterial or venous thrombosis are no exception. [11][12][13][14] Over the last few years, technological advances have made it possible to perform so-called epigenome-wide association studies (EWASs) by the use of bead arrays that allow for genome-wide mapping of DNA methylation at a large number of cytosine-phosphate-guanine (CpG) dinucleotide sites. With regards to arterial thrombotic diseases, EWASs have identified several CpGs that are differentially methylated in cases with myocardial infarction (MI) or ischemic stroke compared with controls.…”

“… 8 9 In addition to genetic variants, there is increasing evidence for the involvement of epigenetic mechanisms, such as DNA methylation, in many human diseases, 10 and those caused by arterial or venous thrombosis are no exception. 11 12 13 14 …”

Impact of homocysteine levels on clinical outcome in patients with acute ischemic stroke receiving intravenous thrombolysis therapy

“…Previous studies have shown that those who have hyperhomocysteinemia (Hhcy) have a higher risk of the development of AIS, and Hhcy is correlated with poor prognosis in AIS patients ( Davis Armstrong et al, 2018 ; Zaric et al, 2019 ). Besides, the increased risk of cardiovascular disease could also be partially attributed to Hhcy ( Borowczyk et al, 2019 ).…”