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BACKGROUND: Stroke is a major cause of serious disability in the United States. Previous studies found multiple associations of serum metabolites with acute ischemic stroke (AIS) compared to controls, but few of them evaluated metabolome in a longitudinal fashion. Therefore, we compared the metabolome of the acute and chronic stages of ischemic stroke. METHODS: We evaluated 1295 serum metabolites from the cohort of 60 stroke patients at acute and chronic stages by performing global metabolomics using ultra-high-performance liquid chromatography/mass spectrometry (LC-MS) and gas chromatography/mass spectrometry (GC-MS). We used Orthogonal Partial Least Square-Discrimination Analysis (OPLS-DA) to inspect group disparity and a mixed regression model to compare metabolites in the acute and chronic stages with Two-Stage Benjamini & Hochberg (TSBH) and Bonferroni correction for multiple testing. RESULTS: The OPLS-DA revealed significant separation of acute and chronic stage metabolites. Mixed regression identified 228 metabolites with TSBH, and 29 metabolites with Bonferroni correction different in acute and chronic stages. At the acute stage, there was a consistent increase of the metabolites of mono/diacylglycerols, sphingolipids, medium/long-chain fatty acids, and amino acids glycine, valine, and tyrosine. At the same time, there was a consistent decrease of the metabolites of acyl-choline related fatty acids, phospholipids, and amino acids alanine, aspartate, and tyramine. Additionally, we identified eight novel metabolites significantly altered at the acute stage of stroke. CONCLUSION: Our pilot study demonstrated significant alterations in metabolomic patterns between the acute and chronic stages of stroke, validating some case-control findings. Future investigation in a larger independent cohort is warranted to identify early biomarkers of acute ischemic stroke.

Background: Hypertriglyceridemia has emerged as a critical coronary artery disease (CAD) risk factor. Rare loss-of function (LoF) variants in apolipoprotein C-III have been reported to reduce triglycerides (TG) and are cardioprotective in American Indians and Europeans. However, there is a lack of data in other Europeans and non-Europeans. Also, whether genetically increased plasma TG due to ApoC-III is causally associated with increased CAD risk is still unclear and inconsistent. The objectives of this study were to verify the cardioprotective role of earlier reported six LoF variants of APOC3 in South Asians and other multi-ethnic cohorts and to evaluate the causal association of TG raising common variants for increasing CAD risk. Methods: We performed gene-centric and Mendelian randomization analyses and evaluated the role of genetic variation encompassing APOC3 for affecting circulating TG and the risk for developing CAD. Results: One rare LoF variant (rs138326449) with a 37% reduction in TG was associated with lowered risk for CAD in Europeans (p = 0.007), but we could not confirm this association in Asian Indians (p = 0.641). Our data could not validate the cardioprotective role of other five LoF variants analysed. A common variant rs5128 in the APOC3 was strongly associated with elevated TG levels showing a p-value 2.8 × 10− 424. Measures of plasma ApoC-III in a small subset of Sikhs revealed a 37% increase in ApoC-III concentrations among homozygous mutant carriers than the wild-type carriers of rs5128. A genetically instrumented per 1SD increment of plasma TG level of 15 mg/dL would cause a mild increase (3%) in the risk for CAD (p = 0.042). Conclusions: Our results highlight the challenges of inclusion of rare variant information in clinical risk assessment and the generalizability of implementation of ApoC-III inhibition for treating atherosclerotic disease. More studies would be needed to confirm whether genetically raised TG and ApoC-III concentrations would increase CAD risk. Ministry of Health (MOH) National Medical Research Council (NMRC) Published version AIDHS/SDS: The Sikh Diabetes Study/ Asian Indian Diabetic Heart Study was supported by NIH grants-R01DK082766; R01DK118427 (NIDDK) and NOT-HG11-009 (NHGRI) and grants from Presbyterian Health Foundation and Harald Hamm Diabetes Center of Oklahoma. Sequencing services were provided through the RS&G Service by the Northwest Genomics Center at the University of Washington, Department of Genome Sciences, under US Federal Government contract number HHSN268201100037C from the National Heart, Lung, and Blood Institute of the NIH. LOLIPOP: The LOLIPOP study is supported by the National Institute for Health Research (NIHR) Comprehensive Biomedical Research Centre Imperial College Healthcare NHS. Trust, the British Heart Foundation (S.P./04/002), the Medical Research Council (G0601966, G0700931), the Wellcome Trust (084723/Z/08/Z, 090532 & 098381) the NIHR (RP-PG-0407-10371), the NIHR Official Development Assistance (ODA, award 16/136/68), the European Union FP7 (EpiMigrant, 279143) and H2020 programs (iHealth-T2D, 643774). We acknowledge the support of the MRC-PHE Centre for Environment and Health, and the NIHR Health Protection Research Unit on Health Impact of Environmental Hazards. The work was carried out in part at the NIHR/Wellcome Trust Imperial Clinical Research Facility. The views expressed are those of the author(s) and not necessarily those of the Imperial College Healthcare NHS. Trust, the NHS, the NIHR, or the Department of Health. We thank the participants and research staff who made the study possible. JC is supported by the Singapore Ministry of Health’s National Medical Research Council under its Singapore Translational Research Investigator (STaR) Award (NMRC/ STaR/0028/2017). SAMAFS: SAMAFS is supported in part by National Institutes of Health (NIH) grants P01 HL045522, R01 DK047482, DK053889, R01 HL113323, R37 MH059490, and T2D-GENES Consortium grants (U01 DK085524, U01 DK085584, U01 DK085501, U01 DK085526, and U01 DK085545). We thank the participants of the San Antonio Family Heart Study and the San Antonio Family Diabetes/Gallbladder Study for their continued cooperation and participation in our research programs. MISS-OLIVER: The OLIVER and MISS are partly supported by NIH grants -R01DK082766 funded by the National Institute of Health (NIDDK), Presbyterian Health Foundation Grants, the College of Medicine Alumni Association grant, and Leinbach Seed Grant from the University of Oklahoma Health Sciences Center. The authors thank all the participants of MISS-OLIVER participants and are grateful for their contribution to this study. UKBB: YT is supported by a Funai Overseas Scholarship from the Funai Foundation for Information Technology and the Stanford University School of Medicine. MAR is partially supported by Stanford University and a National Institute of Health center for Multi-and Trans-ethnic Mapping of Mendelian and Complex Diseases grant (5 U01 HG009080) and partially supported by the National Human Genome Research Institute (NHGRI) of the National Institutes of Health (NIH) under award R01HG010140.