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The field of epigenetics in IS has seen substantial growth, attracting significant interest from clinicians, especially neurologists, as well as researchers in neuroscience and medical sciences. This heightened focus has led to a burgeoning body of literature, including diverse articles[14,15], clinical studies[34,36], systematic reviews, and meta-analyses[6] on various aspects of IS. Although the concept of epigenetics emerged decades ago, substantial research in this area, particularly relating to IS, only began to accelerate around 2015. Despite this progress, comprehensive bibliometric analyses of this niche remains sparse, positioning this study as a trailblazer in providing a detailed bibliometric assessment.
The present analysis reveals a steady increase in publications on epigenetics and IS, starting with early works by Turunen et al.[47] and Baccarelli et al.[12]. Since 2022, there has been a consistent rise in the volume of publications, though at a moderate pace. This study offers a foundational bibliometric review, leveraging the epigenetics framework to map out key authors, influential journals, institutions, and countries involved in IS research. By encompassing all relevant publications up to July 31, 2024, the study delivers a comprehensive snapshot of the field’s evolution, highlighting key contributors and emerging trends.
The bibliometric data indicates a steady growth in publication volume, with an annual increase of 14.9%. Papers in this field average 4.43 years in age and garner approximately 19.2 citations each. The trend towards collaborative research is evident, with no solo authors and international collaboration comprising 31.9% of co-authorships. The Sankey diagram analysis underscores 'Stroke' as a leading journal and identifies prominent contributors such as Israel Fernandez-Cadenas from Spain. Spain is recognized as a key player, though China leads with 16 publications. The publication of Patnala et al.[11] in Molecular Neurobiology has had a significant impact, and top contributing institutions to the topic of epigenetics and IS include Hospital Del Mar Research Institute, Autonomous University of Barcelona, and State University of New York Buffalo.
Past and current research on DNA methylation and ischemic stroke
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This study employs CiteSpace to visualize and analyze trends in epigenetics research. By mapping key themes and intellectual structures, it identifies 10 major thematic clusters and examines their evolution over time. The analysis includes timeline and burst detection, which reveal significant trends in epigenetics related to IS, highlighting both the persistence and development of these research areas.
Over the past decade, research into epigenetics and IS has advanced significantly (Table 1), unveiling complex relationships between genetic and environmental factors[13,47,48]. Early studies primarily focused on how epigenetic modifications, such as DNA methylation, influence stroke pathology[16,17]. Recent research has highlighted the crucial role of these modifications in both stroke risk[6] and recovery[48], particularly through mechanisms like cerebral ischemic preconditioning[29]. This approach holds promise for developing novel treatments by inducing a protective state against severe ischemic events[17]. For instance, the discovery of altered global DNA methylation in stroke patients and its association with various stroke subtypes and atherosclerosis highlights the potential for subtype-specific therapies[16]. Moreover, advancements in epigenetic research, including innovations in mapping DNA methylation and histone modifications, provide essential tools for developing and refining these therapeutic strategies[12,24,26]. By integrating these epigenetic insights with strategies like cerebral ischemic preconditioning, researchers can advance treatment methods and improve stroke management. This approach, informed by ongoing epigenetic research, promises to enhance our ability to protect against and treat severe ischemic events.
Table 1. Genetic loci associated with ischemic stroke identified in research articles published by the top 10 most cited leading authors.
Authors (reference) Types of epigenetic modifications Location of epigenetic modifications Epigenetic regulatory mechanisms Fernandez-Cadenas I; Caty C; Natalia C;
Jerzy K; Joan M;
Elena M[14]Site specific DNA methylation CpG sites within the TRAF gene Reduced DNA methylation of TRAF3, which activates immune responses, was closely linked to vascular recurrence and increased platelet aggregation in IS patients. Fernandez-Cadenas I; Jiménez-Conde J;
Jaume R; Elisa CG; Natalia C; Eva GS[15]Site specific DNA methylation CpG sites within the THBS2, ZFP57, ALOX12, ABI3, ALLC genes Reduced DNA methylation at a CpG site in the THBS2 gene was linked to adverse stroke outcomes at three months. Furthermore, four differentially methylated regions (DMRs) were also associated with stroke outcome at the ZFP57, ALOX12, ABI3, and ALLC genes, which have all been implicated in atherogenesis and cognitive impairment. Fernandez-Cadenas I; Jiménez-Conde J;
Jaume R; Caty C;
Elisa CG; Eva GS;
Joan M[16]Global DNA methylation Genome-wide No global methylation differences were observed among IS subtypes large-artery atherosclerosis, small-artery disease, or cardio-aortic embolism. Fernandez-Cadenas I; Caty C;Natalia C;
Jerzy K; Joan M;
Elena M[37]Site specific DNA methylation CpG sites within the PPM1A gene PPM1A methylation, influencing TGF-β1 signaling and the transcription of plasminogen activator inhibitor-1, was linked to vascular recurrence in aspirin-treated patients. Fernandez-Cadenas I; Jiménez-Conde J;
Jaume R; Jerzy K;
Joan M; Elena M[49]Global DNA methylation CpG sites within the ZFHX3 and MAP3K1 genes Methylation of ZFHX3 and MAP3K1 regulates stroke subtype risk by altering gene expression. Hypomethylation of ZFHX3, involved in myogenic and neuronal differentiation, increases cardioembolic stroke risk, while MAP3K1 shows methylation changes linked to stroke. Mendelian randomization identifies these modifications as key drivers of cardioembolic, atherothrombotic, and lacunar stroke risk. Jiménez-Conde J;
Elisa CG[41]Global DNA methylation Genome-wide IS patients were found to be biologically older than their chronological age, especially in younger individuals, and exhibit significant increases in the Hannum DNA methylation clock. Jiménez-Conde J; Jaume R; Elisa CG;
Eva GS[42]Global DNA methylation Genome-wide The epigenetic clock, determined by DNA methylation, significantly accounts for the burden of white matter hyperintensities, independent of chronological age. Jiménez-Conde J; Jaume R; Elisa CG; Eva GS[43] Global DNA methylation Genome-wide b-Age is a crucial biomarker for predicting stroke recurrence, with higher b-age associated with elevated risk. * These top 10 most cited authors were extracted from Supplementary Table S2b. ABI3: ABI family member 3, ALLC: allantoicase, ALOX12: arachidonate 12-lipoxygenase 12S type, b-Age: biological age, MAP3K1: mitogen-activated protein kinase kinase kinase 1, PPM1A: protein phosphatase, Mg2+/Mn2+ dependent 1A, THBS2: thrombospondin-2, TRAF3: tumor necrosis factor receptor-associated factor 3, protein phosphatase, ZFP57: zinc finger protein 57 homolog, TGF-β1: transforming growth factor beta 1, ZFHX3: Zinc finger homeobox 3. Likewise, advancing our understanding of global DNA methylation patterns is crucial for improving research and treatment strategies for IS. The ENCODE project has provided invaluable insights into genomic features, including transcription regions and chromatin structures, revealing functional elements across 80% of the human genome[50]. These insights demonstrate how non-coding variants, particularly those active during fetal development, impact gene regulation and are associated with IS[38,50]. Shen et al.[38], identified 1,012 differentially methylated CpG sites related to large-artery atherosclerotic stroke, which highlights the significance of DNA methylation as a diagnostic and therapeutic target. Additionally, the findings of Meng et al.[51] on the effect of electroacupuncture in modulating gene expression through histone acetylation further highlights the importance of epigenetic modifications in stroke recovery. Advances in DNA methylation analysis, including the development of biomarkers such as b-Age for predicting stroke recurrence[43], emphasize the need to integrate these epigenetic insights into stroke prevention and management strategies. Key epigenetic markers, such as allele-specific DNA methylation affecting genes like ALOX5AP, have been identified as modulators of stroke phenotypes, suggesting potential targets for intervention[34]. Additionally, hypermethylation of specific genes, including major histocompatibility complex, class II (HLA)-DR beta 1 (DRB1) and HLA-DQ beta 1 (DQB1), has been linked to IS pathology, offering potential biomarkers for disease prognosis and targeted therapies[52].
The integration of epigenetic research with non-invasive brain stimulation techniques is also showing promise in enhancing post-stroke rehabilitation[48]. Methods like transcranial magnetic stimulation and transcranial direct-current stimulation are being investigated for their potential to improve recovery from stroke-induced dysphagia. Although results are mixed, this area of research highlights the need for further validation and exploration[48]. Moreover, there is growing interest in how environmental factors and lifestyle interventions, such as vitamin supplementation[53], impact epigenetic modifications and stroke risk[6]. These developments highlight the increasing recognition of epigenetics as a critical factor in stroke research, opening new avenues for personalized treatments and preventive strategies. The trend toward integrating epigenetic insights into clinical practice reflects a broader shift toward more precise and effective approaches in stroke management and prevention.
Future research directions
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Future research in IS should prioritize the development of targeted therapies that leverage specific epigenetic modifications. Emphasis should be placed on exploring the potential of HDAC inhibitors[11,24-26] and miRNA-based treatments to craft personalized interventions[30,41]. By tailoring therapies to individual epigenetic profiles, these approaches hold promise for more effective and targeted therapeutic outcomes. In addition to therapy development, there is a pressing need for the validation of new biomarkers that can accurately predict stroke risk and progression[28,31]. Research should focus on confirming the diagnostic and prognostic value of various epigenetic markers, including specific DNA methylation sites and circRNAs[31]. This validation process will require studies involving larger and more diverse cohorts to ensure reliability and applicability[28]. Integrating epigenomic data with existing genomic and clinical information presents an opportunity to enhance stroke risk prediction and treatment strategies[15,38,42,44,45]. Employing advanced methodologies such as EWAS and chromatin capture techniques will be crucial for identifying and mapping new stroke-associated genes and pathways[47]. This integration could lead to more precise risk assessments and tailored treatment approaches. The use of advanced technological tools should also be a priority in future research. Innovations such as genome editing, single-cell sequencing, and rapid pyrosequencing offer the potential to provide deeper insights into the molecular mechanisms underlying stroke[3,47]. These technologies could facilitate the discovery of novel therapeutic targets and improve our overall understanding of stroke pathology. Another important area for exploration is the use of b-Age as a biomarker for stroke risk[42,44]. Investigating how DNA methylation can determine b-Age may improve stroke risk assessment and help develop targeted preventative strategies. This approach is particularly relevant for younger individuals who may be biologically older than their chronological age, indicating a higher risk despite their youth[43]. Finally, a comprehensive investigation into global DNA methylation patterns and specific gene methylation changes is essential[17]. Establishing detailed epigenetic profiles could reveal additional factors relevant to IS and guide the development of personalized treatment and monitoring strategies. In summary, integrating insights from epigenetic research with cutting-edge technologies and biomarker discovery is crucial for advancing stroke prevention, diagnosis, and treatment. By adopting a personalized and targeted approach, future research can lead to more effective and individualized interventions, ultimately improving outcomes for patients with IS.
Study limitations
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One limitation of this review reflects the intricate nature of epigenetic modifications and their interactions with other biological factors, which complicates the isolation of specific effects. Although histone modifications and DNA methylation have been identified as key players, they may work interdependently, and their roles are also influenced by a multitude of variables, making it challenging to pinpoint their exact contributions to IS. Additionally, various studies have relied on cross-sectional data, which restricts our ability to establish causal relationships between epigenetic changes and IS. Longitudinal research is needed to better understand how epigenetic modifications evolve and their impact on stroke risk and progression. Likewise, the concept of b-Age as a biomarker for stroke risk, while promising, presents complexities in measurement and interpretation. For example, variability in b-Age assessment methods and a lack of standardization may affect the consistency and clinical relevance of findings. Furthermore, many potential biomarkers, such as specific DNA methylation sites and circRNAs, require validation in larger, more diverse populations to confirm their diagnostic and prognostic value. Thus, while the study offers valuable insights into the role of epigenetics in IS, the limitations such as methodological variability, and the need for further validation underscore the need for future research. Addressing these limitations through larger, more diverse studies and standardized methodologies will be essential for advancing the field and translating findings into effective clinical applications.
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This bibliometric analysis has concluded critical advancements in IS research, offering a comprehensive view of emerging trends, influential authors, and key institutions. Notably, Fernandez-Cadenas Israel has emerged as a pivotal figure in this field, with Spain recognized as a leading contributor, particularly through impactful publications in the esteemed journal Stroke. Evolving research, from unraveling the intricate interplay between genetic and environmental factors to focusing on site-specific and global epigenetic modifications such as DNA methylation, has set the stage for innovative stroke subtype-specific therapies and the identification of crucial molecular biomarkers. Recent studies have highlighted the significance of b-Age and vitamin supplementation in stroke research, alongside an increased emphasis on transcriptional regulation. Investigating how DNA methylation affects b-Age could revolutionize stroke risk assessment and enable the formulation of personalized preventative strategies. This study has compiled recent work demonstrating the impact of epigenetic alterations on stroke pathology, and promising therapeutic targets and biomarkers. Furthermore, the integration of epigenomic data with genomic and clinical insights is essential for advancing stroke risk prediction and treatment methodologies. This research outlines the transformative potential of epigenetics in reshaping our understanding of IS, paving the way for more effective prevention and treatment strategies. By focusing on personalized, targeted approaches, future research can leverage these insights to develop more effective interventions, ultimately enhancing patient outcomes in stroke management.
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Cite this article
Wei LK, Sutherland HG, Griffiths LR. 2024. Epigenetics and ischemic stroke: a bibliometric analysis from 2014 to 2024. Epigenetics Insights 17: e004 doi: 10.48130/epi-0024-0003
Epigenetics and ischemic stroke: a bibliometric analysis from 2014 to 2024
- Received: 05 September 2024
- Revised: 25 September 2024
- Accepted: 27 September 2024
- Published online: 03 December 2024
Abstract: The importance of epigenetic factors in ischemic stroke has become increasingly prominent. Despite this growing interest, comprehensive bibliometric analyses addressing relationships between epigenetic modification and ischemic stroke are still scarce. This study utilizes a range of bibliometric tools to methodically evaluate research advancements, detect key trends, and delineate both historical and emerging research trajectories in this area. By examining 47 pertinent publications from the Web of Science Core Collection up to July 31, 2024, the present analysis uncovers a consistent rise in global research efforts focused on epigenetics and ischemic stroke. Analyses of co-citation and bibliographic coupling reveal significant research clusters that correspond with current thematic trends. Additionally, scientific mapping and citation burst analyses provide insights into the evolving research landscape and highlight emerging areas of interest. These results emphasize the growing role of epigenetics in understanding the mechanisms of ischemic stroke and developing targeted therapeutic approaches.
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Key words:
- Epigenetics /
- Ischemic Stroke /
- Bibliometric /
- DNA methylation /
- Biological age