Stroke genetics informs drug discovery and risk prediction across ancestries

A cross-tissue transcriptome-wide association study identifies new key genes in ischemic stroke

BACKGROUND

Ischemic stroke (IS) is an important disease causing death and disability worldwide, and further investigation of IS-related genes through genome-wide association study (GWAS) data is valuable.

METHODS

The study included GWAS data from 62,100 IS patients of European origin and 1,234,808 controls in a cross-tissue transcriptome association study (TWAS). A joint analysis was first performed by the Unified Test for Molecular Markers (UTMOST) and FUSION methods. The results of the joint analysis were also validated by fine-mapping through FOCUS. Mendelian randomisation analysis was performed to determine whether the obtained genes were causally related to IS. Genome Annotated Multiple Marker Analysis (MAGMA) explored which biological functions the genes associated with IS. We used Coloc to co-localise GWAS and eQTL of the genes. We also biologically validated the results by Western blotting and immunofluorescence staining in the middle cerebral artery occlusion/reperfusion (MCAO/R) mouse model.

RESULTS

Four TWAS methods identified only one new susceptibility gene (USP38) associated with IS risk. Mendelian randomization and colocalization analysis found that USP38 may be protective against IS development. Functional enrichment analysis indicated IS-related genes were mainly associated with the intrinsic fibrinogen activation, acute myocardial infarction, exogenous fibrinogen activation, coagulation cascade response, TNF signalling pathway and GRB2 signalling pathway. Western blotting and immunofluorescence staining demonstrated a reduction in USP38 expression in MCAO/R mice.

CONCLUSION

Our research indicates that USP38 is an essential gene related to IS, with its expression strongly connected with IS risk, thus providing new perspectives on the genetic framework of IS.

Plasma Proteomic Assessment of Calcific Aortic Valve Disease in Older Adults

BACKGROUND

Calcific aortic valve disease (CAVD), and ensuing severe aortic stenosis (AS), is the foremost valvular disorder of aging, yet preventive therapies are lacking. A better understanding of the molecular underpinnings of aortic valve calcification (AVC) is necessary to develop pharmacologic interventions.

METHODS AND RESULTS

We undertook large-scale plasma proteomics in a cohort study of adults ≥65 years old, the CHS (Cardiovascular Health Study), to identify individual proteins associated with echocardiographic AVC and incident moderate/severe AS. Proteomics measurements were performed with the aptamer-based SomaLogic platform of ~5000 proteins. Significant proteins were validated in a second cohort, the AGES-RS (Age, Gene/Environment Susceptibility-Reykjavik Study), which assessed AVC and AS by computed tomography. The potential causal associations of replicated proteins were tested in 2-sample Mendelian randomization using identified cis protein quantitative trait loci in consortia having computed tomography-quantified AVC or AS as outcomes. Six proteins showed Bonferroni-corrected significant relationships with AVC in CHS. Three of these, CXCL-12 (C-X-C chemokine ligand 12), KLKB1 (kallikrein), and leptin, replicated in AGES-RS, of which the former 2 are novel. Only 1 protein, CXCL6, which showed a near-significant association with AS in the replication cohort, was significantly (positively) associated with incident AS. Mendelian randomization analysis was conducted for KLKB1, CXCL12, and CXCL6, which supported a causal relationship for higher KLKB1 with lower AVC (beta=-0.25, P=0.009).

CONCLUSIONS

This study of older adults newly identified and largely replicated associations of 3 circulating proteins with calcific aortic valve disease, of which the relationship of plasma KLKB1 may have a causal basis. Additional investigation is necessary to determine if KLKB1 could be harnessed for calcific aortic valve disease therapeutics.

Monogenic causes of cerebral small vessel disease- models for vascular cognitive impairment and dementia?

PURPOSE OF REVIEW

Recent advancements in molecular biomarkers and therapeutic options for Alzheimer's disease have brought into focus the need for greater progress in the second most common cause of dementia, vascular cognitive impairment and dementia (VCID). We examine how the study of monogenic causes of VCID has contributed to the understanding of its pathophysiology and potential biomarker and treatment research.

RECENT FINDINGS

It is widely accepted that conditions which disrupt the cerebral small vessels contribute to vascular pathologies including stroke and cerebral microbleeds, ultimately leading to vascular cognitive impairment and dementia. Among these conditions are a range of monogenic small vessel diseases (SVDs) such as CADASIL, CARASIL, Fabry disease and COL4A-related disorders.

SUMMARY

This review indicates the importance of furthering research into monogenic SVDs in order to gain insight into the pathomechanisms of VCID more broadly. Monogenic conditions are easier to model than sporadic VCID and can serve as a guide for identifying biomarkers for diagnosis, monitoring and intervention outcomes.

Genetic Analysis of Retinal Cell Types in Neuropsychiatric Disorders

Importance

As an accessible part of the central nervous system, the retina provides a unique window to study pathophysiological mechanisms of brain disorders in humans. Imaging and electrophysiological studies have revealed retinal alterations across several neuropsychiatric and neurological disorders, but it remains largely unclear which specific cell types and biological mechanisms are involved.

Objective

To determine whether specific retinal cell types are affected by genomic risk for neuropsychiatric and neurological disorders and to explore the mechanisms through which genomic risk converges in these cell types.

Design, Setting, and Participants

This genetic association study combined findings from genome-wide association studies in schizophrenia, bipolar disorder, major depressive disorder, multiple sclerosis, Parkinson disease, Alzheimer disease, and stroke with retinal single-cell transcriptomic datasets from humans, macaques, and mice. To identify susceptible cell types, Multi-Marker Analysis of Genomic Annotation (MAGMA) cell-type enrichment analyses were applied and subsequent pathway analyses performed. The cellular top hits were translated to the structural level using retinal optical coherence tomography (acquired between 2009 and 2010) and genotyping data in the large population-based UK Biobank cohort study. Data analysis was conducted between 2022 and 2024.

Main Outcomes and Measures

Cell type-specific enrichment of genetic risk loading for neuropsychiatric and neurological disorder traits in the gene expression profiles of retinal cells.

Results

Expression profiles of amacrine cells (interneurons within the retina) were robustly enriched in schizophrenia genetic risk across mammalian species and in different developmental stages. This enrichment was primarily driven by genes involved in synapse biology. Moreover, expression profiles of retinal immune cell populations were enriched in multiple sclerosis genetic risk. No consistent cell-type associations were found for bipolar disorder, major depressive disorder, Parkinson disease, Alzheimer disease, or stroke. On the structural level, higher polygenic risk for schizophrenia was associated with thinning of the ganglion cell inner plexiform layer, which contains dendrites and synaptic connections of amacrine cells (B, -0.09; 95% CI, -0.16 to -0.03; P = .007; n = 36 349; mean [SD] age, 57.50 [8.00] years; 19 859 female [54.63%]). Higher polygenic risk for multiple sclerosis was associated with increased thickness of the retinal nerve fiber layer (B, 0.06; 95% CI, 0.02 to 0.10; P = .007; n = 36 371; mean [SD] age, 57.51 [8.00] years; 19 843 female [54.56%]).

Conclusions and Relevance

This study provides novel insights into the cellular underpinnings of retinal alterations in neuropsychiatric and neurological disorders and highlights the retina as a potential proxy to study synaptic pathology in schizophrenia.

Reference-Based Standardization Approach Stabilizing Small Batch Risk Prediction via Polygenic Score

The polygenic score (PGS) holds promise for motivating preventive behavioral changes. However, no clinically validated standardization methodology currently exists. Here, we demonstrate the efficacy of a "reference-based" approach for standardization. This method uses the PGS distribution in the general population as a reference for normalization and percentile determination; however, it has not been validated. We investigated three potential influences on PGS computation: (1) the size of the reference population, (2) biases associated with different genotyping platforms, and (3) inclusion of kinship ties within the reference group. Our results indicate that the reference size affects the bootstrap estimate of standard error for PGS percentiles, peaking around the 50th percentile and diminishing at extreme percentiles (1st or 100th). Discrepancies between genotyping platforms, such as different microarrays and whole-genome sequencing, resulted in deviations in PGS (p < 0.05 in Kolmogorov-Smirnov test). However, these deviations were reduced to a nonsignificant level using shared genetic variants in the calculations when the ancestry of the samples and reference were matched. This approach recovered approximately 9.6% of the positive predictive value of PGS by naïve genotype. Our results provide fundamental insights for establishing clinical guidelines for implementing PGS to communicate reliable risks to individuals.

Polygenic score integrating neurodegenerative and vascular risk informs dementia risk stratification

INTRODUCTION

An integrative polygenic risk score (iPRS) capturing the neurodegenerative and vascular contribution to dementia could identify high-risk individuals and improve risk prediction.

METHODS

We developed an iPRS for dementia (iPRS-DEM) in Europeans (aged 65+), comprising genetic risk for Alzheimer's disease (AD) and 23 vascular or neurodegenerative traits (excluding apolipoprotein E [APOE]). iPRS-DEM was evaluated across cohorts comprising older community-dwelling people (N = 3702), a multi-ancestry biobank (N = 130,797 Europeans; 105,404 non-Europeans), and dementia-free memory clinic participants (N = 2032).

RESULTS

iPRS-DEM was associated with dementia risk independently of APOE in the elderly (subdistribution hazard ratio [sHR]per1SD = 1.15, 95% confidence interval [CI]: 1.03 to 1.28), which generalized to Europeans (EUR-sHRper1SD = 1.28, 95% CI: 1.09 to 1.51]), East-Asians (EAS-sHRper1SD = 5.29, 95% CI: 1.43 to 34.36), and memory-clinic participants (sHRper1SD = 1.25, 95% CI: 1.11 to 1.42). Prediction was comparable to clinical risk factors in older community-dwelling people, with improved performance among memory-clinic patients. Risk stratification was enhanced by defining four genetic risk groups with iPRS-DEM and APOE ε4, reaching five-fold increased risk in APOE ε4+/iPRS-DEM+ memory-clinic participants.

DISCUSSION

Alongside APOE ε4, iPRS-DEM may refine risk stratification for the enrichment of dementia clinical trials and prevention programs.

HIGHLIGHTS

iPRS-DEM reflects neurodegenerative and vascular contribution to dementia. We show iPRS-DEM captures additional dementia genetic risk beyond APOE and AD-PRS. iPRS-DEM, in combination with APOE ε4, shows promise for dementia risk stratification. Our results generalize across both population-based and memory-clinic settings. We show transportability of iPRS-DEM to East Asian ancestry.

How epigenetics impacts stroke risk and outcomes through DNA methylation: A systematic review

The impact of DNA methylation (DNAm) on epigenetics has gained prominence in recent years due to its potential influence on ischemic stroke (IS) and treatment outcomes. DNAm is reversible and a better understanding of its role in IS could help identify novel therapeutic targets. The aim of this systematic review was to compile the available data on DNAm in the risk and prognosis of IS and to explore its therapeutic potential. The review process followed the PRISMA criteria. We searched the Pubmed and Cochrane databases to identify studies that used hypothesis free methodological approaches. Of the 459 studies identified, 34 met the inclusion criteria. The studies were categorized as follows: risk of IS; outcomes; and DNAm age. Most studies used genotyping array technology rather than whole-genome sequencing. DNAm testing was mainly based on blood samples. Most studies involved European cohorts. Most of the studies were performed at a single-center with recruitment at the time of stroke. In a few studies, health status was determined longitudinally. This systematic review shows that IS patients are biologically older than expected and present characteristic DNAm patterns related to stroke risk and outcomes. These patterns could be used to develop new treatments with epidrugs.

2025 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2025 AHA Statistical Update is the product of a full year's worth of effort in 2024 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. This year's edition includes a continued focus on health equity across several key domains and enhanced global data that reflect improved methods and incorporation of ≈3000 new data sources since last year's Statistical Update.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

(Apo)Lipoprotein Profiling with Multi-Omics Analysis Identified Medium-HDL-Targeting PSRC1 with Therapeutic Potential for Coronary Artery Disease

Identification of (apo)lipoprotein subclasses causally underpinning atherosclerosis may lead to identification of novel drug targets for treatment of atherosclerotic cardiovascular disease (ASCVD). In this study, observational and genetic associations between (apo)lipoprotein profile and carotid intima-media thickness-assessed atherosclerosis, and risks of coronary artery disease (CAD) and ischemic stroke (IS) are assessed, using data from the UK Biobank study, with further exploration of potential drug target for these two ASCVD subtypes through multi-omics analysis integrating genetic, transcriptomic, and proteomic data. Cholesteryl ester content in medium high-density lipoprotein causally protective of atherosclerosis is identified, plus a target gene, PSRC1, with therapeutic potential for CAD, but not IS, supported by consistent evidence from multi-omics layers of data, which also reveals that such therapeutic potential may be through downregulation of circulating proteins including TRP1, GRNs, and Pla2g12b, and upregulation of Neo1. The results provide strong evidence as well as mechanistic clues of PSRC1's therapeutic potential for CAD.

Genetics of cardiovascular outcomes in individuals with chronic kidney disease: the Chronic Renal Insufficiency Cohort (CRIC) study

Genome-wide association studies (GWAS) identified multiple loci for cardiovascular disease, but their relevance to individuals with chronic kidney disease (CKD), who are at higher risk of cardiovascular disease, is unknown. In this study, we performed GWAS analyses of coronary heart disease (CHD) or all-cause stroke in African (AFR) and European (EUR) American participants with CKD of the Chronic Renal Insufficiency Cohort (CRIC). Mixed- effect logistic regression models were race-stratified and adjusted for age, sex, site of recruitment, estimated glomerular filtration rate (eGFR), and principal components, followed by meta-analysis. We attempted replication in participants from two biobanks with biomarker or ICD-10 (International Classification of Diseases, 10th Revision) diagnostic codes for CKD. We assessed the association of single nucleotide variants (SNVs) at known CHD and stroke loci in CRIC and tested the genetic correlation among CRIC, a biobank-based cohort and published GWAS of cardiovascular disease. Among 3,588 CRIC participants, 1,203 had CHD and 535 had all-cause stroke. We identified six SNVs across three loci ( LINC02744 , AZIN1- AS1 , and ATP6V0A4 ) associated with all-cause stroke, and two intronic SNVs at the PPARG locus associated with CHD. However, SNV associations were not significant in replication studies. Published SNVs for CHD or stroke were not associated with cardiovascular outcomes in CRIC. When testing the genetic correlations between published GWAS and CRIC GWAS, they were significant for CHD (genetic correlations (rg) range of 0.39 to 0.51, p-value< 0.007). These findings suggest some differences in the genetic architecture of CHD and stroke among individuals with CKD compared to those from the general population, although large numbers of CKD participants are needed to assess if findings are related to participant selection and CKD severity, or non-traditional risk factors in people with CKD.

MTHFR Polymorphisms, Homocysteine Elevation, and Ischemic Stroke Susceptibility in East Asian and European Populations

BACKGROUND AND OBJECTIVES

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme that regulates folate and homocysteine metabolism. Genetic variation in MTHFR has been implicated in cerebrovascular disease risk, although research in diverse populations is lacking. We thus aimed to investigate the effect of genetically predicted MTHFR activity on risk of ischemic stroke (IS) and its main subtypes using a multiancestry Mendelian randomization (MR) approach.

METHODS

We proxied reduced MTHFR function using the C677T missense variant that impairs MTHFR function and consequently increases levels of total plasma homocysteine (tHcy) in both East Asian and European populations. Summary data for IS and its subtypes (small vessel stroke [SVS], large artery stroke [LAS], and cardioembolic stroke [CES]) were obtained from the largest available genome-wide association studies. MR estimates were calculated using the Wald ratio and random-effects inverse-variance-weighted methods. We performed sensitivity analyses to evaluate for confounding due to linkage disequilibrium.

RESULTS

Genetically downregulated MTHFR activity, associated with a consequent SD increase in tHcy levels, was associated with an increased risk of SVS in both East Asian (odds ratio [OR] 1.20, 95% CI 1.08-1.34, p = 8.58 × 10-4) and European populations (OR 1.62, 95% CI 1.24-2.12; p = 3.73 × 10-4). There was no evidence that genetically perturbed MTHFR activity influenced risk of CES or LAS. These findings were consistent in sensitivity analyses.

DISCUSSION

Our findings provide genetic evidence that reduced MTHFR activity was selectively associated with an increased risk of SVS in both East Asian and European populations. These findings warrant further investigation of genotype-guided nutritional supplementation for the prevention of SVS.

Kidney multiome-based genetic scorecard reveals convergent coding and regulatory variants

Kidney dysfunction is a major cause of mortality, but its genetic architecture remains elusive. In this study, we conducted a multiancestry genome-wide association study in 2.2 million individuals and identified 1026 (97 previously unknown) independent loci. Ancestry-specific analysis indicated an attenuation of newly identified signals on common variants in European ancestry populations and the power of population diversity for further discoveries. We defined genotype effects on allele-specific gene expression and regulatory circuitries in more than 700 human kidneys and 237,000 cells. We found 1363 coding variants disrupting 782 genes, with 601 genes also targeted by regulatory variants and convergence in 161 genes. Integrating 32 types of genetic information, we present the "Kidney Disease Genetic Scorecard" for prioritizing potentially causal genes, cell types, and druggable targets for kidney disease.

Clinical utility and implementation of polygenic risk scores for predicting cardiovascular disease

Genome-wide association studies have revealed hundreds of genetic variants associated with cardiovascular diseases (CVD). Polygenic risk scores (PRS) can capture this information in a single metric and hold promise for use in CVD risk prediction. Importantly, PRS information can reflect the causally mediated risk to which the individual is exposed throughout life. Although European Society of Cardiology guidelines do not currently advocate their use in routine clinical practice, PRS are commercially available and increasingly sought by clinicians, health systems, and members of the public to inform personalized health care decision-making. This clinical consensus statement provides an overview of the scientific basis of PRS and evidence to date on their role in CVD risk prediction for the purposes of disease prevention. It provides the reader with a summary of the opportunities and challenges for implementation and identifies current gaps in supporting evidence. The document also lays out a potential roadmap by which the scientific and clinical community can navigate any future transition of PRS into routine clinical care. Finally, clinical scenarios are presented where information from PRS may hold most value and discuss organizational frameworks to enable responsible use of PRS testing while more evidence is being generated by clinical studies.

Circulating plasma protein identified as a therapeutic target for intracranial aneurysm through Mendelian Randomization analysis

BACKGROUND

Intracranial aneurysms are the main cause of subarachnoid hemorrhage (SAH), a severe stroke with devastating effects. However, there are no existing medications for intracranial aneurysms (IAs) and novel therapeutic targets are required.

METHODS

We performed a summary data-based Mendelian Randomization (MR) analysis to explore the causal association between circulating plasma proteins and the risk of IAs and SAH. Colocalization analysis was conducted to identify shared causal variants between circulating plasma proteins and IAs, as well as SAH. Finally, mediation MR analyses were conducted to clarify the role of potential plasma proteins in aneurysm formation.

RESULTS

Proteome-wide MR analysis showed that FGF5 (fibroblast growth factor 5) had a causal effect on IA and SAH risk (Pfdr < 0.05). Moreover, genetic variants affecting FGF5 expression levels showed strong evidence of colocalization with IA risk (PPH4 = 0.993) and SAH risk (PPH = 0.988), suggesting that this protein represents a potential direct target for IA intervention. Mediation analysis using two-step MR showed that systolic blood pressure and diastolic blood pressure mediate the effects of FGF5 on IA and SAH.

CONCLUSION

Our investigation identified a causal connection between FGF5 and IAs.

Integrative proteogenomic analysis identifies COL6A3-derived endotrophin as a mediator of the effect of obesity on coronary artery disease

Obesity strongly increases the risk of cardiometabolic diseases, yet the underlying mediators of this relationship are not fully understood. Given that obesity strongly influences circulating protein levels, we investigated proteins mediating the effects of obesity on coronary artery disease, stroke and type 2 diabetes. By integrating two-step proteome-wide Mendelian randomization, colocalization, epigenomics and single-cell RNA sequencing, we identified five mediators and prioritized collagen type VI α3 (COL6A3). COL6A3 levels were strongly increased by body mass index and increased coronary artery disease risk. Notably, the carboxyl terminus product of COL6A3, endotrophin, drove this effect. COL6A3 was highly expressed in disease-relevant cell types and tissues. Finally, we found that body fat reduction could reduce plasma levels of COL6A3-derived endotrophin, indicating a tractable way to modify endotrophin levels. In summary, we provide actionable insights into how circulating proteins mediate the effects of obesity on cardiometabolic diseases and prioritize endotrophin as a potential therapeutic target.

Comparing Alzheimer's genes in African, European, and Amerindian induced pluripotent stem cell-derived microglia

INTRODUCTION

Genome-wide association studies (GWAS) studies in Alzheimer's disease (AD) demonstrate ancestry-specific loci. Previous studies in the regulatory architecture have only been conducted in Europeans (EUs), thus studies in additional ancestries are needed. Given the prevalence of AD genes expressed in microglia, we initiated our studies in induced pluripotent stem cell (iPSC) -derived microglia.

METHODS

We created iPSC-derived microglia from 13 individuals of either high Amerindian (AI), African (AF), or EU global ancestry, including both AD and controls. RNA-seq, ATAC-seq, and pathway analyses were compared between ancestries in both AD and non-AD genes.

RESULTS

Twelve AD genes were differentially expressed genes (DEGs) and/or accessible between ancestries, including ABI3, CTSB, and MS4A6A. A total of 5% of all genes had differential ancestral expression, but differences in accessibility were less than 1%. The DEGs were enriched in known AD pathways.

DISCUSSION

This resource will be valuable in evaluating AD in admixed populations and other neurological disorders and understanding the AD risk differences between populations.

HIGHLIGHTS

First comparison of the genomics of AI, AF, and EU microglia. Report differences in expression and accessibility of AD genes between ancestries. Ancestral expression differences are greater than differences in accessibility. Good transcriptome correlation was seen between brain and iPSC-derived microglia. Differentially expressed AD genes were in known AD pathways.

The Multifaceted Roles of BACH1 in Disease: Implications for Biological Functions and Therapeutic Applications

BTB domain and CNC homolog 1 (BACH1) belongs to the family of basic leucine zipper proteins and is expressed in most mammalian tissues. It can regulate its own expression and play a role in transcriptionally activating or inhibiting downstream target genes. It has a crucial role in various biological processes, such as oxidative stress, cell cycle, heme homeostasis, and immune regulation. Recent research highlights BACH1's significant regulatory roles in a series of conditions, including stem cell pluripotency maintenance and differentiation, growth, senescence, and apoptosis. BACH1 is closely associated with cardiovascular diseases and contributes to angiogenesis, atherosclerosis, restenosis, pathological cardiac hypertrophy, myocardial infarction, and ischemia/reperfusion (I/R) injury. BACH1 promotes tumor cell proliferation and metastasis by altering tumor metabolism and the epithelial-mesenchymal transition phenotype. Moreover, BACH1 appears to show an adverse role in diseases such as neurodegenerative diseases, gastrointestinal disorders, leukemia, pulmonary fibrosis, and skin diseases. Inhibiting BACH1 may be beneficial for treating these diseases. This review summarizes the role of BACH1 and its regulatory mechanism in different cell types and diseases, proposing that precise targeted intervention of BACH1 may provide new strategies for human disease prevention and treatment.

A cis-regulatory element controls expression of histone deacetylase 9 to fine-tune inflammasome-dependent chronic inflammation in atherosclerosis

Common genetic variants in a conserved cis-regulatory element (CRE) at histone deacetylase (HDAC)9 are a major risk factor for cardiovascular disease, including stroke and coronary artery disease. Given the consistency of this association and its proinflammatory properties, we examined the mechanisms whereby HDAC9 regulates vascular inflammation. HDAC9 bound and mediated deacetylation of NLRP3 in the NACHT and LRR domains leading to inflammasome activation and lytic cell death. Targeted deletion of the critical CRE in mice increased Hdac9 expression in myeloid cells to exacerbate inflammasome-dependent chronic inflammation. In human carotid endarterectomy samples, increased HDAC9 expression was associated with atheroprogression and clinical plaque instability. Incorporation of TMP195, a class IIa HDAC inhibitor, into lipoprotein-based nanoparticles to target HDAC9 at the site of myeloid-driven vascular inflammation stabilized atherosclerotic plaques, implying a lower risk of plaque rupture and cardiovascular events. Our findings link HDAC9 to atherogenic inflammation and provide a paradigm for anti-inflammatory therapeutics for atherosclerosis.

Genome-wide and phenome-wide studies provided insights into brain glymphatic system function and its clinical associations

We applied an MRI technique diffusion tensor imaging along the perivascular space (DTI-ALPS) for assessing glymphatic system (GS) in a genome-wide association study (GWAS) and phenome-wide association study (PheWAS) of 40,486 European individuals. Exploratory analysis revealed 17 genetic loci significantly associating with the regional DTI-ALPS index. We found 58 genes, including SPPL2C and EFCAB5, which prioritized in the DTI-ALPS index subtypes and associated with neurodegenerative diseases. PheWAS of 241 traits suggested that body mass index and blood pressure phenotypes closely related to GS function. Moreover, we detected disrupted GS function in 44 of 625 predefined disease conditions. Notably, Mendelian randomization and mediation analysis indicated that lower DTI-ALPS index was a risk factor for ischemic stroke (odds ratio = 1.56, P = 0.028) by partly mediating the risk factor of obesity. Results provide insights into the genetic architecture and mechanism for the DIT-ALPS index and highlight its great clinical value, especially in cerebral stroke.

Genome-wide association study unravels mechanisms of brain glymphatic activity

Brain glymphatic activity, as indicated by diffusion-tensor imaging analysis along the perivascular space (ALPS) index, is involved in developmental neuropsychiatric and neurodegenerative diseases, but its genetic architecture is poorly understood. Here, we identified 17 unique genome-wide significant loci and 161 candidate genes linked to the ALPS-indexes in a discovery sample of 31,021 individuals from the UK Biobank. Seven loci were replicated in two independent datasets. Genetic signals located at the 2p23.3 locus yielded significantly concordant effects in both young and aging cohorts. Genetic correlation and polygenic overlap analyses indicate a common underlying genetic mechanism between the ALPS-index, ventricular volumes, and cerebrospinal fluid tau levels, with GMNC (3q28) and C16orf95 (16q24.2) as the shared genetic basis. Our findings enhance the understanding of the genetics of the ALPS-index and provide insight for further research into the neurobiological mechanisms of glymphatic clearance activity across the lifespan and its relation to neuropsychiatric phenotypes.

The genomic architecture of circulating cytokine levels points to drug targets for immune-related diseases

Circulating cytokines orchestrate immune reactions and are promising drug targets for immune-mediated and inflammatory diseases. Exploring the genetic architecture of circulating cytokine levels could yield key insights into causal mediators of human disease. Here, we performed genome-wide association studies (GWAS) for 40 circulating cytokines in meta-analyses of 74,783 individuals. We detected 359 significant associations between cytokine levels and variants in 169 independent loci, including 150 trans- and 19 cis-acting loci. Integration with transcriptomic data point to key regulatory mechanisms, such as the buffering function of the Atypical Chemokine Receptor 1 (ACKR1) acting as scavenger for multiple chemokines and the role of tumor necrosis factor receptor-associated factor 1 (TRAFD1) in modulating the cytokine storm triggered by TNF signaling. Applying Mendelian randomization (MR), we detected a network of complex cytokine interconnections with TNF-b, VEGF, and IL-1ra exhibiting pleiotropic downstream effects on multiple cytokines. Drug target cis-MR using 2 independent proteomics datasets paired with colocalization revealed G-CSF/CSF-3 and CXCL9/MIG as potential causal mediators of asthma and Crohn's disease, respectively, but also a potentially protective role of TNF-b in multiple sclerosis. Our results provide an overview of the genetic architecture of circulating cytokines and could guide the development of targeted immunotherapies.

Recent Advances in Stroke Genetics-Unraveling the Complexity of Cerebral Infarction: A Brief Review

BACKGROUND/OBJECTIVES

Recent advances in stroke genetics have substantially enhanced our understanding of the complex genetic architecture underlying cerebral infarction and other stroke subtypes. As knowledge in this field expands, healthcare providers must remain informed about these latest developments. This review aims to provide a comprehensive overview of recent advances in stroke genetics, with a focus on cerebral infarction, and discuss their potential impact on patient care and future research directions.

METHODS

We reviewed recent literature about advances in stroke genetics, focusing on cerebral infarction, and discussed their potential impact on patient care and future research directions. Key developments include the identification of monogenic stroke syndromes, such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy, and cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy caused by mutations in the NOTCH3 and HTRA1 genes, respectively. In addition, the role of RNF213 in moyamoya disease and other cerebrovascular disorders, particularly in East Asian populations, has been elucidated. The development of polygenic risk scores for assessing genetic predisposition to stroke has demonstrated the potential to improve risk prediction beyond traditional factors. Genetic studies have also elucidated the distinct genetic architecture of stroke subtypes, including large artery atherosclerosis, small vessel disease, and cardioembolic stroke. Furthermore, the investigation of epigenetic modifications influencing stroke risk and its outcomes has revealed new research avenues, while advancements in pharmacogenomics highlight the potential for personalized stroke treatment based on individual genetic profiles.

CONCLUSIONS

These genetic discoveries have important clinical implications, including improved risk stratification, targeted prevention strategies, and the development of novel therapeutic approaches.

Clusters of parental socioeconomic status in early childhood and inherited risk for cerebrovascular disease until mid-life-Northern Finland Birth Cohort 1966

BACKGROUND AND AIMS

The incidence of cerebrovascular disease (CVD) is rising among young adults (< 55 years). The risk for CVD starts to form in early childhood and is comprised of genetic and environmental risk factors. The aim of this study is to investigate the relationship between early family socioeconomic status (SES), inherited risk, and CVD until midlife.

METHODS

In the Northern Finland Birth Cohort 1966 of 12,058 children, individuals were followed from gestational period up to 54 years. We used previously published early family SES clusters, based on latent class analysis of a wide set of prenatally collected variables. We investigated inherited risk with polygenic risk score (PRS) and parental CVDs during follow-up. The associations of the five distinct clusters, inherited risk, and consequent risk for various types of CVDs until middle age were analyzed with Cox regression. All analyses were conducted first in the whole sample and then stratified by sex as is recommended in cardiovascular studies.

RESULTS

During the follow-up of 586,943 person-years, 512 CVDs occurred. No clear association between SES clusters and CVD were found. Higher PRS associated with any CVD (hazard ratio (HR) per 1 SD increase: 1.15; 95% confidence interval (CI): 1.02-1.31), and ischemic CVD (HR: 1.21; 1.05-1.40). We found no combined associations of early family SES and inherited risk for CVD.

CONCLUSIONS

Inherited risk was associated with the risk for CVD in mid-life in Finnish population. We found no clear connection with early family SES and CVD. Being born to a specific SES group did not increase the effect of inherited risk.

DATA ACCESS STATEMENT

NFBC1966 data are available from the University of Oulu, Infrastructure for Population Studies for researchers who meet the criteria for accessing confidential data. In the use of data, we follow the EU general data protection regulation (679/2016) and Finnish Data Protection Act. Permission to use the data can be applied for research purposes from https://www.oulu.fi/nfbc.

Integrating transcriptomic and polygenic risk scores to enhance predictive accuracy for ischemic stroke subtypes

Ischemic stroke (IS), characterized by complex etiological diversity, is a significant global health challenge. Recent advancements in genome-wide association studies (GWAS) and transcriptomic profiling offer promising avenues for enhanced risk prediction and understanding of disease mechanisms. GWAS summary statistics from the GIGASTROKE Consortium and genetic and phenotypic data from the UK Biobank (UKB) were used. Transcriptome-Wide Association Studies (TWAS) were conducted using FUSION to identify genes associated with IS and its subtypes across eight tissues. Colocalization analysis identified shared genetic variants influencing both gene expression and disease risk. Sum Transcriptome-Polygenic Risk Scores (STPRS) models were constructed by combining polygenic risk scores (PRS) and polygenic transcriptome risk scores (PTRS) using logistic regression. The predictive performance of STPRS was evaluated using the area under the curve (AUC). A Phenome-wide association study (PheWAS) explored associations between STPRS and various phenotypes. TWAS identified 34 susceptibility genes associated with IS and its subtypes. Colocalization analysis revealed 18 genes with a posterior probability (PP) H4 > 75% for joint expression quantitative trait loci (eQTL) and GWAS associations, highlighting their genetic relevance. The STPRS models demonstrated superior predictive accuracy compared to conventional PRS, showing significant associations with numerous UKB phenotypes, including atrial fibrillation and blood pressure. Integrating transcriptomic data with polygenic risk scores through STPRS enhances predictive accuracy for IS and its subtypes. This approach refines our understanding of the genetic and molecular landscape of stroke and paves the way for tailored preventive and therapeutic strategies.

Genetically Confirmed Optimal Causal Association of Cerebrospinal Fluid Metabolites With Hemorrhagic Stroke

Hemorrhagic stroke (HS) mainly includes intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH), both of which seriously affect the patient's prognosis. Cerebrospinal fluid (CSF) metabolites and HS showed a link in observational studies. However, the causal association between them is not clear. We aimed to establish the optimal causality of CSF metabolites with HS. Mendelian randomization (MR) was employed to identify associations between CSF metabolites and different sources of HS. Univariable MR and false discovery rates (FDR) were used to identify initial causal associations. Linkage disequilibrium score regression determined genetic correlations. Multiple sensitive analyses ensured the reliability of the results. Multivariable MR and MR Bayesian Model Averaging were used to identify the optimal causal associations. The combined effects of metabolites and HS were assessed by meta-analyses. Pathway analyses were performed to identify potential pathways of action. Reverse MR was also conducted to identify reverse causal associations. Finally, Corresponding blood metabolites were used to explore the multiple roles of metabolites. We identified 20 CSF metabolites and six metabolic pathways associated with ICH; 15 CSF metabolites and three metabolic pathways associated with SAH. Nineteen and seven metabolites were causally associated with deep and lobar ICH, respectively. CSF levels of mannose (OR 0.63; 95% CI 0.45-0.88; Pcombined = 0.0059) and N-acetyltaurine (OR 0.68; 95% CI 0.47-0.98; Pcombined = 0.0395) may serve as the optimal exposures for ICH and SAH, respectively. Additionally, CSF ascorbic acid 3-sulfate levels significantly decrease the risk of deep ICH (OR 0.79; 95% CI 0.66-0.94; p = 0.0065; PFDR = 0.091). Supplemental analysis of blood metabolites suggested multiple roles for CSF and blood N-formylanthranilic acid and hippurate. There are significant causal associations between CSF metabolites and HS, which provides a further rationale for the prevention and monitoring of ICH and SAH.

Gut Microbiome and Stroke: a Bidirectional Mendelian Randomisation Study in East Asian and European Populations

BACKGROUND AND AIMS

Observational studies have implicated the involvement of gut microbiome in stroke development. Conversely, stroke may disrupt the gut microbiome balance, potentially causing systemic infections exacerbated brain infarction. However, the causal relationship remains controversial or unknown. To investigate bidirectional causality and potential ethnic differences, we conducted a bidirectional two-sample Mendelian randomisation (MR) study in both East Asian (EAS) and European (EU) populations.

METHODS

Leveraging the hitherto largest genome-wide association study (GWAS) summary data from the MiBioGen Consortium (n=18 340, EU) and BGI (n=2524, EAS) for the gut microbiome, stroke GWAS data from the GIGASTROKE Consortium(264 655 EAS and 1 308 460 EU), we conducted bidirectional MR and sensitivity analyses separately for the EAS and EU population.

RESULTS

We identified nominally significant associations between 85 gut microbiomes taxa in EAS and 64 gut microbiomes taxa in EU with stroke or its subtypes. Following multiple testing, we observed that genetically determined 1 SD increase in the relative abundance of species Bacteroides pectinophilus decreased the risk of cardioembolic stroke onset by 28% (OR 0.72 (95% CI 0.62 to 0.84); p=4.22e-5), and that genetically determined 1 SD increase in class Negativicutes resulted in a 0.76% risk increase in small vessel stroke in EAS. No significant causal association was identified in the EU population and the reverse MR analysis.

CONCLUSION

Our study revealed subtype-specific and population-specific causal associations between gut microbiome and stroke risk among EAS and EU populations. The identified causality holds promise for developing a new stroke prevention strategy, warrants further mechanistic validation and necessitates clinical trial studies.

Mendelian randomization analysis reveals causal effects of migraine and its subtypes on early-onset ischemic stroke risk

Previous observational studies have suggested at a potential link between migraine, particularly migraine with aura, and the susceptibility to early-onset ischemic stroke. We aimed to investigate the causal effects of genetically determined migraine and its subtypes on the risk of early-onset ischemic stroke using the two-sample Mendelian randomization method. Genetic instrumental variables associated with migraine and its subtypes were acquired from two sources with the largest sample sizes available. Summary data for early-onset ischemic stroke was acquired from a study encompassing individuals aged 18-59 years, comprising 16,730 cases and 599,237 non-stroke controls. The random-effects inverse variance weighted method was used as the primary analysis approach. Additionally, linkage disequilibrium score regression analysis was used to evaluate the genetic correlation. The Mendelian randomization analysis revealed no association between overall migraine and migraine without aura with the risk of early-onset ischemic stroke. However, migraine with aura showed a suggestive association with an elevated risk of early-onset ischemic stroke, with odds ratios of 1.114 (95% confidence interval = 1.005 to 1.236, p-value = 0.040) and 1.062 (95% confidence interval = 1.002 to 1.126, p-value = 0.042) based on instruments from two independent sources. The odds ratio was 1.074 (95% confidence interval = 1.022 to 1.130, p-value = 0.005) based on instruments from both two sources. No evidence of heterogeneity or horizontal pleiotropy was found. By contrast, migraine with aura was not related to ischemic stroke in all adults. Furthermore, a significant positive genetic correlation was found between migraine with aura and early-onset ischemic stroke (genetic correlation = 0.208, 95% confidence interval = 0.038 to 0.377, p-value = 0.016). This study provides evidence of a causal relationship between migraine with aura and the risk of early-onset ischemic stroke, as well as a positive genetic correlation between them.

Identification of shared genetic etiology of cardiovascular and cerebrovascular diseases through common cardiometabolic risk factors

Cardiovascular diseases (CVDs) and cerebrovascular diseases (CeVDs) are closely related vascular diseases, sharing common cardiometabolic risk factors (RFs). Although pleiotropic genetic variants of these two diseases have been reported, their underlying pathological mechanisms are still unclear. Leveraging GWAS summary data and using genetic correlation, pleiotropic variants identification, and colocalization analyses, we identified 11 colocalized loci for CVDs-CeVDs-BP (blood pressure), CVDs-CeVDs-LIP (lipid traits), and CVDs-CeVDs-cIMT (carotid intima-media thickness) triplets. No shared causal loci were found for CVDs-CeVDs-T2D (type 2 diabetes) or CVDs-CeVDs-BMI (body mass index) triplets. The 11 loci were mapped to 12 genes, namely CASZ1, CDKN1A, TWIST1, CDKN2B, ABO, SWAP70, SH2B3, LRCH1, FES, GOSR2, RPRML, and LDLR, where both GOSR2 and RPRML were mapped to one locus. They were enriched in pathways related to cellular response to external stimulus and regulation of the phosphate metabolic process and were highly expressed in endothelial cells, epithelial cells, and smooth muscle cells. Multi-omics analysis revealed methylation of two genes (CASZ1 and LRCH1) may play a causal role in the genetic pleiotropy. Notably, these pleiotropic loci are highly enriched in the targets of antihypertensive drugs, which further emphasizes the role of the blood pressure regulation pathway in the shared etiology of CVDs and CeVDs.

An atlas of the shared genetic architecture between atopic and gastrointestinal diseases

Comorbidity among atopic diseases (ADs) and gastrointestinal diseases (GIDs) has been repeatedly demonstrated by epidemiological studies, whereas the shared genetic liability remains largely unknown. Here we establish an atlas of the shared genetic architecture between 10 ADs or related traits and 11 GIDs, comprehensively investigating the comorbidity-associated genomic regions, cell types, genes and genetically predicted causality. Although distinct genetic correlations between AD-GID are observed, including 14 genome-wide and 28 regional correlations, genetic factors of Crohn's disease (CD), ulcerative colitis (UC), celiac disease and asthma subtypes are converged on CD4+ T cells consistently across relevant tissues. Fourteen genes are associated with comorbidities, with three genes are known treatment targets, showing probabilities for drug repurposing. Lower expressions of WDR18 and GPX4 in PBMC CD4+ T cells predict decreased risk of CD and asthma, which could be novel drug targets. MR unveils certain ADs led to higher risk of GIDs or vice versa. Taken together, here we show distinct genetic correlations between AD-GID pairs, but the correlated genomic loci converge on the dysregulation of CD4+ T cells. Inhibiting WDR18 and GPX4 expressions might be candidate therapeutic strategies for CD and asthma. Estimated causality indicates potential guidance for preventing comorbidity.

Dietary salt intake is not associated with risk of stroke: A Mendelian randomization study

Previous studies have demonstrated a correlation between dietary salt intake and stroke; however, there was a lack of conclusive evidence regarding a causal connection between them. We undertook a two-sample Mendelian randomization (MR) study to examine their potential association. The genome-wide data for dietary salt intake was sourced from genome-wide association study that involved 462,630 samples. Genetic instruments for stroke were also obtained from genome-wide association study, which included 446,696 samples. Both samples were from European. The inverse variance weighting was used as the main method in MR analysis. We also performed several complementary MR methods, including MR-Egger, position weighted median, simple model, and weighted model. Our results showed that there was no causal relationship between dietary salt intake and stroke, which was genetically determined (fixed-effects inverse variance weighted: odds ratio, 0.95; 95% confidence interval, 0.74-1.21; P  = .67). Neither Cochran Q test (P = .52) nor MR-Egger method (P = .48) found obvious heterogeneity; in addition, the MR pleiotropy residual sum and outliers global test (P = .52) and MR-Egger regression intercept (P = .74) also showed no pleiotropy. The result of our MR study showed that there was no direct causal relationship between dietary salt intake and stroke risk. More studies were required to further confirm the stability of this relationship and to trying applied the findings to the clinic.

Prioritizing protein targets for dyslipidaemia and cardiovascular diseases using Mendelian randomization in South Asians

South Asians are at higher risk of dyslipidaemia-a modifiable risk factor for cardiovascular diseases (CVDs). We aimed to identify protein targets for dyslipidaemia and CVDs in this population. We used a two-sample Mendelian randomization (MR) approach, supplemented with MR-Egger, weighted median, colocalization, and generalized MR (GMR), to evaluate the effect of 2,800 plasma proteins on high/low/non-high-density lipoprotein cholesterol (HDL-C/LDL-C/nonHDL-C), total cholesterol, and triglycerides. Observational analyses were conducted on MR findings with strong colocalization (posterior probability≥ 80%) and GMR findings. Univariate MR assessed lipid-associated proteins' effect on CVDs. Finally, we compared the potential causal effects of plasma proteins on lipids in South Asians with those in Europeans to study heterogeneity in the MR effects. We identified 29 genetically proxied proteins potentially causal to at least one lipid measure, 12 of which showed strong colocalization and GMR evidence, including ANGPTL3 and PCSK9. Notably, PCSK9 demonstrated a stronger association with LDL-C in European compared to South Asian (βEuropean= 0.37; 95% Confidence Interval (CI)= (0.36, 0.38), βSouth Asian= 0.16; 95% CI= (0.11, 0.21)). Observational analysis suggested significant interaction between PCSK9 levels with LDL-C levels in South Asians with South Asians having a significantly lower effect compared to other ethnicities (PCSK9*South Asian; β= -0.14; 95% CI= (-0.174, -0.107)). Additionally, we showed that CELSR2 is also linked with CAD in South Asians. Our study highlighted potential causal links between plasma proteins, dyslipidaemia, and CVD in South Asians, with significant heterogeneity across genetic ancestry groups. Larger studies in South Asians are needed to validate these findings.

Optimizing treatment of cardiovascular risk factors in cerebral small vessel disease using genetics

Cerebral small vessel disease (cSVD) causes lacunar stroke (LS), intracerebral haemorrhage, and is the most common pathology underlying vascular dementia. However, there are few trials examining whether treating conventional cardiovascular risk factors reduce stroke risk in cSVD, as opposed to stroke as a whole. We used Mendelian randomization techniques to investigate which risk factors are causally related to cSVD and to evaluate whether specific drugs may be beneficial in cSVD prevention. We identified genetic proxies for blood pressure traits, lipids, glycaemic markers, anthropometry measures, smoking, alcohol consumption, and physical activity from large-scale genome-wide association studies of European ancestry. We also selected genetic variants as proxies for drug target perturbation in hypertension, dyslipidaemia, hyperglycaemia, and obesity. Mendelian randomization was performed to assess their associations with LS from the GIGASTROKE Consortium (n = 6811) and in a sensitivity analysis in a cohort of patients with MRI-confirmed LS (n = 3306). We also investigated associations with three neuroimaging features of cSVD, namely, white matter hyperintensities (n = 55 291), fractional anisotropy (n = 36 460), and mean diffusivity (n = 36 012). Genetic predisposition to higher systolic and diastolic blood pressure was associated with LS and cSVD imaging markers. Genetically predicted liability to diabetes, obesity, smoking, higher triglyceride levels, and the ratio of triglycerides to high density lipoprotein (HDL) also showed detrimental associations with LS risk, while genetic predisposition to higher HDL concentrations and moderate-to-vigorous physical activity showed protective associations. Genetically proxied blood pressure-lowering through calcium channel blockers (CCBs) was associated with cSVD imaging markers, while genetically proxied HDL-raising through Cholesteryl Ester Transfer Protein (CETP) inhibitors, triglyceride-lowering through lipoprotein lipase (LPL), and weight-lowering through gastric inhibitory polypeptide receptor (GIPR) were associated with lower risk of LS. Our findings highlight the importance of some conventional cardiovascular risk factors, including blood pressure and BMI, in cSVD, but not other e.g. LDL. The findings further demonstrate the potential beneficial effects of CCBs on cSVD imaging markers and CETP inhibitors, LPL enhancement, and GIPR obesity-targeted drugs on LS. They provide useful information for initiating future clinical trials examining secondary prevention strategies in cSVD.

Single-nucleus RNA sequencing of human periventricular white matter in vascular dementia

Vascular dementia (VaD) refers to a variety of dementias driven by cerebrovascular disease and is the second leading cause of dementia globally. VaD may be caused by ischemic strokes, intracerebral hemorrhage, and/or cerebral small vessel disease, commonly identified as white matter hyperintensities on MRI. The mechanisms underlying these white matter lesions in the periventricular brain are poorly understood. In this study we perform an extensive transcriptomic analysis on human postmortem periventricular white matter lesions in patients with VaD with the goal of identifying molecular pathways in the disease. We find increased cellular stress responses in astrocytes, oligodendrocytes, and oligodendrocyte precursor cells as well as transcriptional and translational repression in microglia in our dataset. We show that several genes identified by GWAS as being associated with white matter disease are differentially expressed in cells in VaD. Finally, we compare our dataset to an independent snRNAseq dataset of PVWM in VaD and a scRNAseq dataset on human iPSC-derived microglia exposed to oxygen glucose deprivation (OGD). We identify the increase of the heat shock protein response as a conserved feature of VaD across celltypes and show that this increase is not linked to OGD exposure. Overall, our study is the first to show that increased heat shock protein responses are a common feature of lesioned PVWM in VaD and may represent a potential therapeutic target.

Leveraging Mendelian randomization to inform drug discovery and development for ischemic stroke

Discovery and development of efficacious and safe pharmacological therapies is fraught with challenges. As proteins constitute the majority of drug targets and are encoded by genes, naturally occurring genetic variation within populations can provide valuable insights to inform drug discovery and development efforts. The drug target Mendelian randomization (MR) paradigm leverages these principles to investigate the causal effects of drug targets in humans. This review examines the application of drug target MR in informing the efficacy and development of therapeutics for ischemic stroke prevention and treatment. We consider applications of MR for existing and novel treatment strategies, including targeting blood pressure, lipid metabolism, coagulation, inflammation and glycemic control. Several of these genetically supported targets are under evaluation in late-stage clinical trials. Methodological limitations of drug target MR are addressed, followed by an outline of future research directions. We anticipate that careful application of drug target MR will enhance the efficiency of drug development for ischemic stroke, consequently accelerating the delivery of effective medications to patients.

Genomic Landscape of Thrombosis Recurrence Risk Across Venous Thromboembolism Subtypes

Venous thromboembolism (VT) is a frequent (annual incidence of 1 to 2 per 1,000) and potentially life-threatening (case-fatality rate up to 10%) disease. VT is associated with serious short-term and long-term complications including a recurrence rate of approximately 20% within five years. Anticoagulant therapy, the mainstay of VT treatment, drastically reduces the risk of early VT recurrence, but it exposes patients to a substantial risk of bleeding. We analysed the genomic architecture of VT recurrence using data from 6,571 patients across eight cohorts, 1,816 of whom experienced recurrence, with a particular focus on the clinical manifestation of the type of first VT event. Through genome-wide association studies (GWAS), we identified three loci significantly associated (P<5×10-8) with VT recurrence in the general VT population: GPR149/MME, L3MBTL4, and THSD7B. Protein Quantitative Trait Locus and Mendelian Randomization analyses further identified elevated plasma levels of coagulation factor XI and GOLM2 as risk factors for recurrence, while decreased levels of PCSK9 and pro-IL16 were linked to reduced VT recurrence risk. Subgroup analyses revealed 18 loci associated with VT recurrence, with notable differences between pulmonary embolism (PE) and deep vein thrombosis (DVT). For example, the exonic variant SLC4A1 p.Glu40Lys was significantly associated with recurrence in PE patients (Hazard Ratio (HR)=3.23, P=9.7×10-12) but showed no effect in DVT (HR=1.00, P=0.98). These findings emphasize the role of specific genetic loci and protein pathways in influencing VT recurrence and provide valuable insights into potential therapeutic targets. Further research is needed to clarify the biological mechanisms driving these associations.

Causal relationship of inflammatory cytokines and serum metabolites in cerebral small vessel disease: a two-step Mendelian randomization study

BACKGROUND AND PURPOSE

The aim was to investigate the causal relationships of inflammatory cytokines and serum metabolites in cerebral small vessel disease (CSVD).

METHODS

Bidirectional Mendelian randomization was first conducted to screen inflammatory cytokines and serum metabolites that were associated with imaging features of CSVD, including white matter hyperintensities, recent small subcortical infarcts, cortical cerebral microinfarcts, cerebral microbleeds, lacunes and enlarged perivascular spaces. Sensitivity analyses were performed to evaluate the robustness and pleiotropy of these results. Subsequently, inflammatory cytokines and serum metabolites that were associated with CSVD were subjected to functional enrichment. Finally, mediation analysis was employed to investigate whether inflammatory cytokines or serum metabolites acted as an intermediary for the other in their causal relationship with CSVD.

RESULTS

Of the inflammatory cytokines, five were risk factors (e.g., tumour-necrosis-factor-related apoptosis-inducing ligand) and five (e.g., fibroblast growth factor 19) were protective factors for CSVD. Eleven serum metabolites that increased CSVD risk and 13 metabolites that decreased CSVD risk were also identified. The majority of these markers of CSVD susceptibility were lipid metabolites. Natural killer cell receptor sub-type 2B4 was determined to act as a mediating factor of an unidentified metabolite for the enlargement of perivascular spaces.

CONCLUSION

Several inflammatory cytokines and serum metabolites had causal relationships with imaging features of CSVD. A natural killer cell receptor mediated in part the promotional effect of a metabolite on perivascular space enlargement.

Multidimensional Approach of Genotype and Phenotype in Stroke Etiology: The MAGPIE Study

Background and Aims

Stroke is a leading cause of mortality and morbidity in Bangladesh. It is estimated that genetic determinants account for around 40%-60% of its etiology, similar to environmental factors. This study aimed to provide a better understanding of the genetic, environmental, and clinical risk factors in stroke patients from Bangladesh.

Methods

The MAGPIE (Multidimensional Approach of Genotype and Phenotype In Stroke Etiology) study is a population-based case-control study that will allow a hypothesis-free genome-wide association study (GWAS) to identify genetic risk factors associated with adult stroke (age ≥ 18 years) in Bangladesh. This study will collect detailed phenotypic data as well as blood samples from stroke patients and control subjects. High-molecular-weight genomic DNA will be isolated and archived using Qiagen DNA isolation kits.

Results

We will utilize SPSS v28.0, vR-4.3.2 and gPLINK v2.0 software to analyse the study variables, as appropriate. Further, appropriate statistical tests will be applied to test the significance level between study groups. As applicable, data will be presented in tables and graphs, such as Manhattan plots and Quantile-Quantile (QQ) plots. A p < 0.05 will be considered as statistical significance.

Conclusion

This will be the first large-scale carefully phenotyped biobank of Bangladeshi stroke patients which will enable a GWAS enabling an understanding of the association between gene-phenotype risk factors which has the potential to revise and refine national stroke guidelines.

Serum liver enzymes and risk of stroke: Systematic review with meta-analyses and Mendelian randomization studies

BACKGROUND AND PURPOSE

Previous observational studies have identified correlations between liver enzyme levels and stroke risk. However, the strength and consistency of these associations vary. To comprehensively evaluate the relationship between liver enzymes and stroke risk, we conducted meta-analyses complemented by Mendelian randomization (MR) analyses.

METHODS

Following the PRISMA guidelines, we performed meta-analyses of prospective studies and conducted subgroup analyses stratified by sex and stroke subtype. Subsequently, adhering to the STROBE-MR guidelines, we performed two-sample bidirectional univariable MR (UVMR) and multivariable MR (MVMR) analyses using the largest genome-wide association studies summary data. Finally, the single-nucleotide polymorphisms associated with liver enzymes on sex differences underwent gene annotation, gene set enrichment, and tissue enrichment analyses.

RESULTS

In the meta-analyses of 17 prospective studies, we found the relative risks for serum γ-glutamyl transferase (GGT) and alkaline phosphatase (ALP) were 1.23 (95% CI: 1.16-1.31) and 1.3 (95% CI: 1.19-1.43), respectively. Subgroup analyses revealed sex and stroke subtype differences in liver enzyme-related stroke risk. Bidirectional UVMR analyses confirmed that elevated GGT, alanine aminotransferase, and aspartate aminotransferase levels were associated with increased stroke occurrence. The primary results from the MVMR analyses revealed that higher ALP levels significantly increased the risk of stroke and ischemic stroke. Gene set and tissue enrichment analyses supported genetic differences in liver enzymes across sexes.

CONCLUSIONS

Our study provides evidence linking liver enzyme levels to stroke risk, suggesting liver enzymes as potential biomarkers for early identification of high-risk individuals. Personalized, sex-specific interventions targeting liver enzymes could offer new strategies for stroke prevention.

Genome-wide association analysis to search for new loci associated with stroke risk in Northwestern Chinese population

BACKGROUND AND PURPOSE

Genetic factors play an important role in the pathogenesis of stroke(S). This study aimed to screen the loci associated with S risk in northwestern Chinese population by genome-wide association analysis (GWAS).

METHODS

A total of 1394 subjects, including 682 S patients and 692 controls, were enrolled in this study. SPSS 25.0 software was used for statistical analysis, and the independent sample t-test as well as Chi-square test were used to analyze the differences in age and gender between the case and control groups. The Precision Medicine Diversity Array (PMDA) genotyping chip was used in this study. The genotyping platform was the Gene Titan multi-channel instrument, and the Axiom Analysis Suite 6.0 software was used for the data analyzing. Besides, the LASSO analysis, SNP-SNP and GO/KEGG analysis were conducted to analyze the association between significant loci and S risk.

RESULTS

A total of 30 SNPs were found to be associated with the S risk based on additive model (p < 5 × 10-8). After the LASSO screening, 22 SNPs showed the diagnostic value in S. The SNPs interaction analysis further screened the SNP-SNP interaction groups associated with the S risk(p < 0.05). Finally, the GO/KEGG analysis discovered the suggestive significance loci could be involved in the S development mainly by immune-related functions and pathways.

CONCLUSION

This study discovered 30 S related SNPs and analyzed the potential pathways associated with genes located on the 30 SNPs, which were beneficial for enriching the genetic mechanism analysis of S in northwestern Chinese population.

Health-Related Behaviors and Risk of Common Age-Related Brain Diseases Across Severities of Genetic Risk

BACKGROUND AND OBJECTIVES

The 21-point Brain Care Score (BCS) is an index that ranks behaviors and clinical measurements with the aim of encouraging lifestyle adjustments to lower the incidence of age-related brain disease, including stroke, late-life depression (LLD), and dementia. A higher BCS at baseline is associated with a lower risk of these outcomes. We aimed to investigate whether the associations between BCS and stroke, LLD, and dementia risks are independent of genetic predisposition for these conditions and quantify the effect of healthy lifestyle across genetic risk distributions for these outcomes.

METHODS

Using the UK Biobank (UKB) prospective cohort study, we computed baseline BCSs and polygenic scores to estimate genetic predisposition for stroke and LLD and APOE ε allele status to stratify dementia risk. As for outcomes again in UKB, we measured incidence of stroke, LLD, and dementia. We used multivariate Cox proportional hazard models to assess associations between BCS, genetic predisposition, and these outcomes. We also conducted stratified and interaction analyses to estimate the incidence of these outcomes across quartiles of genetic risk and BCS.

RESULTS

We included 368,340 UKB participants (median age 58 years (interquartile range 51-63 years), 46.3% male). Independent of genetic risk, a 5-point increase in BCS corresponded to lowered hazards of stroke (hazard ratio [HR] 0.70, 95% CI 0.68-0.73), LLD (HR 0.65, 95% CI 0.63-0.67), and dementia (HR 0.82, 95% CI 0.78-0.85). Incidences of all 3 outcomes were higher among participants with high genetic risk of these outcomes. However, these increased risks were offset for individuals with a higher BCS (incidence rates per 1,000 person-years were 2.76 vs 1.19 for stroke, 7.34 vs 4.46 for LLD, and 3.64 vs 2.05 for dementia, when comparing low and high BCS).

DISCUSSION

Across different genetic predispositions for stroke, LLD, and dementia, healthier lifestyle behaviors are protective for brain health, demonstrating the nondeterminism of genetic risk. Furthermore, differences in BCS behave as aggregate risk estimators of all 3 outcomes. Further work is needed to prospectively investigate the utility and performance of the BCS as a targeted intervention in populations at elevated genetic risk of age-related brain disease.

Polygenic prediction for underrepresented populations through transfer learning by utilizing genetic similarity shared with European populations

Because current genome-wide association studies are primarily conducted in individuals of European ancestry and information disparities exist among different populations, the polygenic score derived from Europeans thus exhibits poor transferability. Borrowing the idea of transfer learning, which enables the utilization of knowledge acquired from auxiliary samples to enhance learning capability in target samples, we propose transPGS, a novel polygenic score method, for genetic prediction in underrepresented populations by leveraging genetic similarity shared between the European and non-European populations while explaining the trans-ethnic difference in linkage disequilibrium (LD) and effect sizes. We demonstrate the usefulness and robustness of transPGS in elevated prediction accuracy via individual-level and summary-level simulations and apply it to seven continuous phenotypes and three diseases in the African, Chinese, and East Asian populations of the UK Biobank and Genetic Epidemiology Research Study on Adult Health and Aging cohorts. We further reveal that distinct LD and minor allele frequency patterns across ancestral groups are responsible for the dissatisfactory portability of PGS.

DNA Methylation Signatures of Cardiovascular Health Provide Insights into Diseases

Background

The association of overall cardiovascular health (CVH) with changes in DNA methylation (DNAm) has not been well characterized.

Methods

We calculated the American Heart Association's Life's Essential 8 (LE8) score to reflect CVH in five cohorts with diverse ancestry backgrounds. Epigenome-wide association studies (EWAS) for LE8 score were conducted, followed by bioinformatic analyses. DNAm loci significantly associated with LE8 score were used to calculate a CVH DNAm score. We examined the association of the CVH DNAm score with incident CVD, CVD-specific mortality, and all-cause mortality.

Results

We identified 609 CpGs associated with LE8 score at false discovery rate (FDR) < 0.05 in the discovery analysis and at Bonferroni corrected P < 0.05 in the multi-cohort replication stage. Most had low-to-moderate heterogeneity (414 CpGs [68.0%] with I2 < 0.2) in replication analysis. Pathway enrichment analyses and phenome-wide association study (PheWAS) search associated these CpGs with inflammatory or autoimmune phenotypes. We observed enrichment for phenotypes in the EWAS catalog, with 29-fold enrichment for stroke (P = 2.4e-15) and 21-fold for ischemic heart disease (P = 7.4e-38). Two-sample Mendelian randomization (MR) analysis showed significant association between 141 CpGs and ten phenotypes (261 CpG-phenotype pairs) at FDR < 0.05. For example, hypomethylation at cg20544516 (MIR33B; SREBF1) associated with lower risk of stroke (P = 8.1e-6). In multivariable prospective analyses, the CVH DNAm score was consistently associated with clinical outcomes across participating cohorts, the reduction in risk of incident CVD, CVD mortality, and all-cause mortality per standard deviation increase in the DNAm score ranged from 19% to 32%, 28% to 40%, and 27% to 45%, respectively.

Conclusions

We identified new DNAm signatures for CVH across diverse cohorts. Our analyses indicate that immune response-related pathways may be the key mechanism underpinning the association between CVH and clinical outcomes.

Effect of genetically predicted sclerostin on cardiovascular biomarkers, risk factors, and disease outcomes

Sclerostin inhibitors protect against osteoporotic fractures, but their cardiovascular safety remains unclear. We conducted a cis-Mendelian randomisation analysis to estimate the causal effect of sclerostin levels on cardiovascular risk factors. We meta-analysed three GWAS of sclerostin levels including 49,568 Europeans and selected 2 SNPs to be used as instruments. We included heel bone mineral density and hip fracture risk as positive control outcomes. Public GWAS and UK Biobank patient-level data were used for the study outcomes, which include cardiovascular events, risk factors, and biomarkers. Lower sclerostin levels were associated with higher bone mineral density and 85% reduction in hip fracture risk. However, genetically predicted lower sclerostin levels led to 25-85% excess coronary artery disease risk, 40% to 60% increased risk of type 2 diabetes, and worse cardiovascular biomarkers values, including higher triglycerides, and decreased HDL cholesterol levels. Results also suggest a potential (but borderline) association with increased risk of myocardial infarction. Our study provides genetic evidence of a causal relationship between reduced levels of sclerostin and improved bone health and fracture protection, but increased risk of cardiovascular events and risk factors.

Exploring the Link Between Genetic Predictors of Cardiovascular Disease and Psoriasis

Importance

The epidemiological link between immune-mediated diseases (IMIDs) and cardiovascular disease has often been attributed to systemic inflammation. However, the direction of causality and the biological mechanisms linking cardiovascular disease with IMIDs are incompletely understood. Given the robust epidemiological association and the growing body of supportive mechanistic evidence, psoriasis is an exemplary IMID model for exploring this relationship.

Objective

To assess the bidirectional relationships between genetic predictors of psoriasis and the 2 major forms of cardiovascular disease, coronary artery disease (CAD) and stroke, and to evaluate the association between genetic predictors of cardiovascular disease with 9 other IMIDs.

Design, Setting, and Participants

This was a genetic association study using mendelian randomization (MR), a powerful genetic tool to help distinguish causation from associations observed in epidemiological studies, to provide supportive evidence for causality between traits. The study conducted 2-sample MR analyses using summary-level data from large-scale genome-wide association meta-analysis studies (GWAS) for each trait. The analysis focused on individuals of European descent from GWAS meta-analyses, involving CAD, stroke, psoriasis, and 9 other IMIDs. Data were analyzed from January 2023 to May 2024.

Exposures

Genetic predictors of CAD, stroke, psoriasis, and 9 other IMIDs.

Main Outcomes and Measures

The primary outcomes were the associations of genetic predictors of CAD and stroke with the risk of psoriasis and 9 other IMIDs, determined using inverse-variance weighted (IVW) MR estimates.

Results

This study included 181 249 cases and 1 165 690 controls with CAD, 110 182 cases and 1 503 898 controls with stroke, 36 466 cases and 458 078 controls with psoriasis, for a total of approximately 3 400 000 individuals, and 9 other IMIDs. In contrast to previous assumptions, genetic predictors of psoriasis were found to have no association with CAD or stroke. In the reverse direction, genetic predictors of both CAD (MR estimate IVW odds ratio [OR], 1.07; 95% CI, 1.04-1.10; P = .003) and stroke (IVW OR, 1.22; 95% CI, 1.05-1.41; P = .01) were found to have risk-increasing associations with psoriasis. Adjusting for stroke rendered the associations of genetically predicted CAD with psoriasis risk nonsignificant (and vice versa), suggesting that a shared effect underlying genetic risk for CAD and stroke associates with increased psoriasis risk. No risk-increasing associations were observed for genetic predictors of cardiovascular disease with other common IMIDs, including rheumatoid arthritis and inflammatory bowel disease.

Conclusions and Relevance

Findings of this mendelian randomization study indicate that genetic predictors of cardiovascular disease were associated with increased psoriasis risk with no reciprocal effect or association with other IMIDs. Elucidating mechanisms underpinning this association could lead to novel therapeutic approaches in both diseases.

Application of proteomics for novel drug discovery and risk prediction optimisation in stroke and myocardial infarction: a review of in-human studies

The use of proteomics in human studies investigating stroke and myocardial infarction (MI) has been increasing, prompting a review of the literature. This revealed proteinaceous biomarkers of stroke from thrombi, brain tissue, cells, and particles, some of which cross the blood-brain barrier (BBB). Several proteins were also implicated in coronary artery disease (CAD), which often underlies MI, cholesterol transportation, and inflammation. Furthermore, the platelet proteome revealed itself as a potential therapeutic target, along with differentially expressed proteins associated with MI progression. Moreover, proteomic data enhanced the performance of conventional risk scores and causal protein discovery has improved interventions and drug development for patients with MI and other conditions. These findings suggest that proteomics holds much promise for future stroke and MI research.

Life's Essential 8 Trajectories and Risk of Stroke: A Prospective Cohort Study

BACKGROUND

Evidence is lacking regarding long-term patterns of change in Life's Essential 8 (LE8) and their association with the risk of stroke. We aim to evaluate LE8 trajectories and examine their association with the risk of stroke in China.

METHODS

This study, conducted in a workplace setting, recruited 26 719 participants (average age, 46.02±11.27 years and a male population of 73.73%) who had no history of stroke and consecutively participated in 6 surveys from 2006 to 2016. Repeated LE8 measurements were determined by taking the unweighted average of the 8 component scores ranging from 0 to 100. People with higher scores had better overall cardiovascular health. By examining the medical records of the participants, stroke cases were identified for the period from 2016 to 2020. A latent mixture model was applied to classify the trajectory clusters of LE8 from 2006 to 2016, and Cox proportional hazard models were used to analyze the data.

RESULTS

Five LE8 trajectories were detected between 2006 and 2016. Four hundred ninety-eight incident strokes including 55 (11.04%) hemorrhagic and 458 (91.97%) ischemic strokes were documented. After adjusting for covariates, the hazard ratios and 95% CIs for the association between stable-low, moderate-increasing, moderate-stable, and high-stable trajectories and incident stroke, compared with the moderate-decreasing trajectory, were 1.42 (1.11-1.84), 0.73 (0.56-0.96), 0.49 (0.39-0.62), and 0.19 (0.11-0.32), respectively. Individuals with high LE8 status (LE8≥80) exhibited a significantly reduced risk of stroke compared with those with low one (LE8≤49; P-trend <0.001). A faster annual growth in LE8 was related to a lower risk of stroke.

CONCLUSIONS

Maintaining high LE8 over an extended period and high baseline LE8 status were related to a decreased risk of stroke. Despite the initial low level of LE8, improvement in LE8 attenuates or even reverses the risk of stroke.

COVID-19 Is a Coronary Artery Disease Risk Equivalent and Exhibits a Genetic Interaction With ABO Blood Type

BACKGROUND

COVID-19 is associated with acute risk of major adverse cardiac events (MACE), including myocardial infarction, stroke, and mortality (all-cause). However, the duration and underlying determinants of heightened risk of cardiovascular disease and MACE post-COVID-19 are not known.

METHODS

Data from the UK Biobank was used to identify COVID-19 cases (n=10 005) who were positive for polymerase chain reaction (PCR+)-based tests for SARS-CoV-2 infection (n=8062) or received hospital-based International Classification of Diseases version-10 (ICD-10) codes for COVID-19 (n=1943) between February 1, 2020 and December 31, 2020. Population controls (n=217 730) and propensity score-matched controls (n=38 860) were also drawn from the UK Biobank during the same period. Proportional hazard models were used to evaluate COVID-19 for association with long-term (>1000 days) risk of MACE and as a coronary artery disease risk equivalent. Additional analyses examined whether COVID-19 interacted with genetic determinants to affect the risk of MACE and its components.

RESULTS

The risk of MACE was elevated in COVID-19 cases at all levels of severity (HR, 2.09 [95% CI, 1.94-2.25]; P<0.0005) and to a greater extent in cases hospitalized for COVID-19 (HR, 3.85 [95% CI, 3.51-4.24]; P<0.0005). Hospitalization for COVID-19 represented a coronary artery disease risk equivalent since incident MACE risk among cases without history of cardiovascular disease was even higher than that observed in patients with cardiovascular disease without COVID-19 (HR, 1.21 [95% CI, 1.08-1.37]; P<0.005). A significant genetic interaction was observed between the ABO locus and hospitalization for COVID-19 (Pinteraction=0.01), with risk of thrombotic events being increased in subjects with non-O blood types (HR, 1.65 [95% CI, 1.29-2.09]; P=4.8×10-5) to a greater extent than subjects with blood type O (HR, 0.96 [95% CI, 0.66-1.39]; P=0.82).

CONCLUSIONS

Hospitalization for COVID-19 represents a coronary artery disease risk equivalent, with post-acute myocardial infarction and stroke risk particularly heightened in non-O blood types. These results may have important clinical implications and represent, to our knowledge, one of the first examples of a gene-pathogen exposure interaction for thrombotic events.

A Guide to Understanding Mendelian Randomization Studies

Epidemiology provides a powerful framework for characterizing exposure-disease relationships, but its utility for making causal inferences is limited because epidemiologic data are observational in nature and subject to biases stemming from undetected confounding variables and reverse causation. Mendelian randomization (MR) is an increasingly popular method used to circumvent these limitations. MR uses genetic variants, or instruments, as a natural experiment to proxy an exposure, thus allowing estimation of causal effects upon an outcome that are minimally affected by the usual biases present in epidemiologic studies. Notably, MR relies on three core assumptions related to the selection of the genetic instruments, and adherence to these assumptions must be carefully evaluated to assess the validity of the causal estimates. The goal of this review is to provide readers with a basic understanding of MR studies and how to read and evaluate them. Specifically, we outline the basics of how MR analysis is conducted, the assumptions underlying instrument selection, and how to assess the quality of MR studies.

The effects of immunomodulatory drugs on cerebral small vessel disease: A mediation Mendelian randomization analysis

BACKGROUND

There are only a few recognized drug targets for cerebral small vessel disease (CSVD). Though inflammation is increasingly implicated in the development of CSVD, it remains unclear whether immunomodulation could become a therapeutic target. Accordingly, the Mendelian randomization (MR) method was used to assess the genetically proxied impacts of IL6 receptor (IL6R) inhibitor, IL1β inhibitor, Tumor necrosis factor (TNF) inhibitor and β-tubulin inhibitor on CSVD through.

METHODS

Single nucleotide polymorphisms (SNPs) near the IL6R, IL1β, TNFRSF1A and β-tubulin genes were identified as genetic proxies for immunomodulatory drugs. These SNPs exhibited significant associations with serum C-reactive protein (CRP) levels in a large European genome-wide association study. The causal effects of immunomodulatory drugs on CSVD manifestations and the mediation influence of 731 peripheral blood immune phenotypes linking these drugs to CSVD manifestations were examined using a two-sample two-step MR approach.

RESULTS

A total of 9, 18, 4 and 1 SNP were identified to proxy the effects of IL1β inhibitor, IL6R inhibitor, TNF inhibitor and β-tubulin inhibitor, respectively. MR analysis showed a significant causal relationship between IL1β inhibition and reduced volume of periventricular white matter hyperintensity (PWMH). IL6R inhibition was associated with a reduced risk of small vessel stroke, decreased axial diffusivity and mean diffusivity. Genetically proxied TNF inhibition may decrease the occurrence of cerebral microbleeds (CMBs) and severe enlarged perivascular spaces located at white matter (WM-EPVS). It could also protect WM integrity, as evidenced by the reduced volumes of PWMH and deep white matter hyperintensity (DWMH). Various peripheral blood immune phenotypes exhibited significant associations with immunomodulatory drugs. Notably, the median fluorescence intensity (MFI) of CD45 on CD8br cells partially mediated the effects of IL1β inhibitor on PWMH volume. Indirect effects of TNF inhibition on PWMH and DWMH volume through the MFI of CD127 on CD28- CD8br cells were observed. The effects of TNF inhibition on the occurrence of any CMBs were partially mediated by the MFI of CD45 on natural killer T cells, and the effects of TNF inhibition on the occurrence of lobar CMBs were partially mediated by the MFI of HLA DR on CD33- HLA DR+ cells. Furthermore, the MFI of HLA DR on CD33- HLA DR+ cells partially mediated the effects of TNF inhibition on WM-EPVS.

CONCLUSIONS

IL1β inhibitor, IL6R inhibitor and TNF inhibitor were associated with lower burden of CSVD while the activation of certain immune cells such as Tregs and myeloid cells partially mediated their protective effects.

The role of genetically predicted serum iron levels on neurodegenerative and cardiovascular traits

Iron is an essential mineral that supports numerous biological functions. Studies have reported associations between iron dysregulation and certain cardiovascular and neurodegenerative diseases, but the direction of influence is not clear. Our goal was to use computational approaches to better understand the role of genetically predicted iron levels on disease risk. We meta-analyzed genome-wide association study summary statistics for serum iron levels from two cohorts and two previous meta-analyses. We then obtained summary statistics from 11 neurodegenerative, cerebrovascular, cardiovascular or lipid traits to assess global and regional genetic correlation between iron levels and these traits. We used two-sample Mendelian randomization (MR) to estimate causal effects. Sex-stratified analyses were also carried out to identify effects potentially differing by sex. Overall, we identified three significant global correlations between iron levels and (i) coronary heart disease, (ii) triglycerides, and (iii) high-density lipoprotein (HDL) cholesterol levels. A total of 194 genomic regions had significant (after correction for multiple testing) local correlations between iron levels and the 11 tested traits. MR analysis revealed two potential causal relationships, between genetically predicted iron levels and (i) total cholesterol or (ii) non-HDL cholesterol. Sex-stratified analyses suggested a potential protective effect of iron levels on Parkinson's disease risk in females, but not in males. Our results will contribute to a better understanding of the genetic basis underlying iron in cardiovascular and neurological health in aging, and to the eventual identification of new preventive interventions or therapeutic avenues for diseases which affect women and men worldwide.