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Cureus Jul 2022Single nucleotide polymorphisms (SNPs) in the genetic makeup of the methylenetetrahydrofolate reductase gene ( C677-T, A1298-C, and G1793-A) alongside environmental and... (Review)
Review
Single nucleotide polymorphisms (SNPs) in the genetic makeup of the methylenetetrahydrofolate reductase gene ( C677-T, A1298-C, and G1793-A) alongside environmental and lifestyle component has shown some links as a potential factor responsible for male infertility across the globe posing huge genetic vulnerability to the gender. However, SNPs in the gene implicated in male infertility are not without their own controversial results even within the same population. The goal of this study was to provide comprehensive insights into the controversial nature of gene polymorphism on male infertility across all Indian populations as well as other ethnicities. The electronic PubMed database was utilized to conduct and select eligible studies for this systematic review (update to December 2021). Only high-quality studies with a link between polymorphisms and male infertility were included based on our exclusion and inclusion criteria. The connection between the gene polymorphism and male infertility in Indian population studies was evaluated using odds ratios (ORs) with a 95% confidence interval (CI). A total of five studies presenting 1,237 cases and 1,044 controls were assessed for this study. The collective results revealed that C667-T and A1298-C gene polymorphism were significantly linked with an increased chance of male infertility both in south India and north India, however, with some conflicting results. Interestingly, no study has been carried out to investigate the impact of G1793-A polymorphism on infertile males in the Indian population at the time of our report. Results generated from the few case-control evaluated on gene polymorphism in the Indian population are found to conflict with some extrinsic factors (such as nutritional status-folate metabolism, lifestyle, varying recruitment procedures, and epigenetic elements) identified to have played some critical roles. Therefore, broader studies across all regions in India addressing the grave impact of gene polymorphism on male infertility are of utmost importance.
PubMed: 36000135
DOI: 10.7759/cureus.27075 -
BMC Genomics Mar 2022Environmental exposures in utero which modify DNA methylation may have a long-lasting impact on health and disease in offspring. We aimed to identify and replicate...
BACKGROUND
Environmental exposures in utero which modify DNA methylation may have a long-lasting impact on health and disease in offspring. We aimed to identify and replicate previously published genomic loci where DNA methylation changes are attributable to in utero exposures in the NutriGen birth cohort studies Alliance.
METHODS
We reviewed the literature to identify differentially methylated sites of newborn DNA which are associated with the following five traits of interest maternal diabetes, pre-pregnancy body mass index (BMI), diet during pregnancy, smoking, and gestational age. We then attempted to replicate these published associations in the Canadian Healthy Infant Longitudinal Development (CHILD) and the South Asian birth cohort (START) cord blood epigenome-wide data.
RESULTS
We screened 68 full-text articles and identified a total of 17 cord blood epigenome-wide association studies (EWAS) of the traits of interest. Out of the 290 CpG sites reported, 19 were identified in more than one study; all of them associated with maternal smoking. In CHILD and START EWAS, thousands of sites associated with gestational age were identified and maintained significance after correction for multiple testing. In CHILD, there was differential methylation observed for 8 of the published maternal smoking sites. No other traits tested (i.e., folate levels, gestational diabetes, birthweight) replicated in the CHILD or START cohorts.
CONCLUSIONS
Maternal smoking during pregnancy and gestational age are strongly associated with differential methylation in offspring cord blood, as assessed in the EWAS literature and our birth cohorts. There are a limited number of reported methylation sites associated in more than two independent studies related to pregnancy. Additional large studies of diverse populations with fine phenotyping are needed to produce robust epigenome-wide data in order to further elucidate the effect of intrauterine exposures on the infants' methylome.
Topics: Canada; DNA Methylation; Epigenome; Female; Fetal Blood; Genome-Wide Association Study; Humans; Infant, Newborn; Pregnancy
PubMed: 35305575
DOI: 10.1186/s12864-022-08451-6 -
Child Abuse & Neglect Dec 2021Epigenetics offers one promising method for assessing the psychobiological response to stressful experiences during childhood. In particular, deoxyribonucleic acid (DNA)... (Review)
Review
BACKGROUND
Epigenetics offers one promising method for assessing the psychobiological response to stressful experiences during childhood. In particular, deoxyribonucleic acid (DNA) methylation has been associated with an altered hypothalamus-pituitary-adrenal (HPA) axis and the onset of mental disorders. Equally, there are promising leads regarding the association between the methylation of the glucocorticoid receptor gene (NR3C1-1) and child maltreatment and its link with HPA axis and psychopathology.
OBJECTIVE
The current study aimed to assess the evidence of a link among child maltreatment, NR3C1-1 methylation, HPA axis deregulation, and symptoms of psychopathology.
METHODS
We followed the Prisma guidelines and identified 11 articles that met our inclusion criteria.
RESULTS
We found that eight studies (72.72%) reported increased NR3C1-1 methylation associated with child maltreatment, specifically physical abuse, emotional abuse, sexual abuse, neglect, and exposure to intimate partner violence, while three studies (27.27%) found no significant association. Furthermore, a minority of studies (36.36%) provided additional measures of symptoms of psychopathology or cortisol in order to examine the link among NR3C1-1 methylation, HPA axis deregulation, and psychopathology in a situation of child maltreatment. These results suggest that NR3C1-1 hypermethylation is positively associated with higher HPA axis activity, i.e. increased production of cortisol, as well as symptoms of psychopathology, including emotional lability-negativity, externalizing behavior symptoms, and depressive symptoms.
CONCLUSION
NR3C1-1 methylation could be one mechanism that links altered HPA axis activity with the development of psychopathology.
Topics: Child; Child Abuse; DNA Methylation; Exons; Humans; Hypothalamo-Hypophyseal System; Pituitary-Adrenal System; Receptors, Glucocorticoid
PubMed: 34488052
DOI: 10.1016/j.chiabu.2021.105304 -
Life (Basel, Switzerland) Feb 2024Osteoarthritis is a leading cause of disability in the world. The scientific literature highlights the critical importance of epigenetic regulatory effects, intertwined... (Review)
Review
Osteoarthritis is a leading cause of disability in the world. The scientific literature highlights the critical importance of epigenetic regulatory effects, intertwined with biomechanical and biochemical peculiar conditions within each musculoskeletal district. While the contribution of genetic and epigenetic factors to knee OA is well-recognized, their precise role in disease management remains an area of active research. Such a field is particularly heterogeneous, calling for regular analysis and summarizing of the data that constantly emerge in the scientific literature, often sparse and scant of integration. The aim of this study was to systematically identify and synthesize all new evidence that emerged in human and animal model studies published between 2020 and 2023. This was necessary because, to the best of our knowledge, articles published before 2019 (and partly 2020) had already been included in systematic reviews that allowed to identify the ones concerning the knee joint. The review was carried out in accordance with Preferential Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only peer-reviewed articles were considered for inclusion. A total of 40 studies were identified, showing promising results in terms either of biomarker identification, new insight in mechanism of action or potential therapeutic targets for knee OA. DNA methylation, histone modification and ncRNA were all mechanisms involved in epigenetic regulation of the knee. Most recent evidence suggests that epigenetics is a most promising field with the long-term goal of improving understanding and management of knee OA, but a variety of research approaches need greater consolidation.
PubMed: 38398778
DOI: 10.3390/life14020269 -
Clinical Epigenetics Jul 2023To systematically evaluate the efficacy and safety of FDA-approved isocitrate dehydrogenase (IDH) inhibitors in the treatment of IDH-mutated acute myeloid leukemia (AML). (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
To systematically evaluate the efficacy and safety of FDA-approved isocitrate dehydrogenase (IDH) inhibitors in the treatment of IDH-mutated acute myeloid leukemia (AML).
METHODS
We used R software to conduct a meta-analysis of prospective clinical trials of IDH inhibitors in the treatment of IDH-mutated AML published in PubMed, Embase, Clinical Trials, Cochrane Library and Web of Science from inception to November 15th, 2022.
RESULTS
A total of 1109 IDH-mutated AML patients from 10 articles (11 cohorts) were included in our meta-analysis. The CR rate, ORR rate, 2-year survival (OS) rate and 2-year event-free survival (EFS) rate of newly diagnosed IDH-mutated AML (715 patients) were 47%, 65%, 45% and 29%, respectively. The CR rate, ORR rate, 2-year OS rate, median OS and median EFS of relapsed or refractory (R/R) IDH-mutated AML (394 patients) were 21%, 40%, 15%, 8.21 months and 4.73 months, respectively. Gastrointestinal adverse events were the most frequently occurring all-grade adverse events and hematologic adverse events were the most frequently occurring ≥ grade 3 adverse events.
CONCLUSION
IDH inhibitor is a promising treatment for R/R AML patients with IDH mutations. For patients with newly diagnosed IDH-mutated AML, IDH inhibitors may not be optimal therapeutic agents due to low CR rates. The safety of IDH inhibitors is controllable, but physicians should always pay attention to and manage the differentiation syndrome adverse events caused by IDH inhibitors. The above conclusions need more large samples and high-quality RCTs in the future to verify.
Topics: Humans; Prospective Studies; DNA Methylation; Leukemia, Myeloid, Acute; Enzyme Inhibitors; Mutation
PubMed: 37434249
DOI: 10.1186/s13148-023-01529-2 -
Lifestyle Genomics 2023DNA methylation patterns are directly associated with diverse metabolic disorders. The status of methyl-donor micronutrients has been associated with DNA methylation... (Meta-Analysis)
Meta-Analysis
BACKGROUND
DNA methylation patterns are directly associated with diverse metabolic disorders. The status of methyl-donor micronutrients has been associated with DNA methylation levels, and altered ingestion of folate, choline, betaine, B vitamins and methionine may impact genes both globally and at the level of promoter regions. Despite this, the role of methyl-donor micronutrient supplementation on DNA methylation profiles is currently unclear.
OBJECTIVES
The aims of this systematic review and meta-analysis were to identify and synthesize the evidence about methyl-donor nutrient supplementation on DNA methylation.
METHODS
A systematic literature search was performed in Medline, Embase, Scopus, and Web of Science databases with a combination of terms related to DNA methylation assessment, supplementation, and methyl-donor nutrients. Studies (in vitro, animal models, or human clinical trials) were included if DNA methylation levels after any kind of methyl-donor micronutrient supplementation or treatment was investigated. Studies were assessed for bias using Revised Cochrane risk-of-bias tool for randomized trials, risk-of-bias in Non-randomized Studies of Interventions or Systematic Review Centre for Laboratory Animal Experimentation tools. Data were extracted from studies measuring DNA methylation levels in any sample or tissue, following any kind of methyl-donor micronutrient supplementation or treatment. Separate random-effects meta-analyses were performed for animal model studies and human clinical trials that examined the effects of folic acid supplementation on DNA methylation.
RESULTS
Fifty-seven studies were included in this systematic review: 18 human clinical trials, 35 in animal model, and 4 in vitro studies. Concerning overall risk of bias, most of the studies were classified as "high risk" or "some concerns." Meta-analysis with meta-regression from studies in animal models showed that folic acid dose significantly affected DNA methylation and that high and very high doses showed increases in DNA methylation when compared to low doses. However, meta-analysis of human clinical trials showed that folic acid supplementation did not promote significant changes in DNA methylation when compared to placebo.
CONCLUSION
Folic acid supplementation may change global DNA methylation levels in animals supplemented with high, as compared to low, doses. Heterogeneity in studies and supplementation protocols make it difficult to establish clinical recommendations. However, these effects, even if small, might be of clinical importance in the management of patients with diseases related to DNA hypomethylation.
Topics: Humans; Animals; DNA Methylation; Folic Acid; Dietary Supplements; Vitamin B Complex; Micronutrients
PubMed: 37935134
DOI: 10.1159/000533193 -
Neural Regeneration Research Dec 2024The search for reliable and easily accessible biomarkers in Parkinson's disease is receiving a growing emphasis, to detect neurodegeneration from the prodromal phase and...
The search for reliable and easily accessible biomarkers in Parkinson's disease is receiving a growing emphasis, to detect neurodegeneration from the prodromal phase and to enforce disease-modifying therapies. Despite the need for non-invasively accessible biomarkers, the majority of the studies have pointed to cerebrospinal fluid or peripheral biopsies biomarkers, which require invasive collection procedures. Saliva represents an easily accessible biofluid and an incredibly wide source of molecular biomarkers. In the present study, after presenting the morphological and biological bases for looking at saliva in the search of biomarkers for Parkinson's disease, we systematically reviewed the results achieved so far in the saliva of different cohorts of Parkinson's disease patients. A comprehensive literature search on PubMed and SCOPUS led to the discovery of 289 articles. After screening and exclusion, 34 relevant articles were derived for systematic review. Alpha-synuclein, the histopathological hallmark of Parkinson's disease, has been the most investigated Parkinson's disease biomarker in saliva, with oligomeric alpha-synuclein consistently found increased in Parkinson's disease patients in comparison to healthy controls, while conflicting results have been reported regarding the levels of total alpha-synuclein and phosphorylated alpha-synuclein, and few studies described an increased oligomeric alpha-synuclein/total alpha-synuclein ratio in Parkinson's disease. Beyond alpha-synuclein, other biomarkers targeting different molecular pathways have been explored in the saliva of Parkinson's disease patients: total tau, phosphorylated tau, amyloid-β1-42 (pathological protein aggregation biomarkers); DJ-1, heme-oxygenase-1, metabolites (altered energy homeostasis biomarkers); MAPLC-3beta (aberrant proteostasis biomarker); cortisol, tumor necrosis factor-alpha (inflammation biomarkers); DNA methylation, miRNA (DNA/RNA defects biomarkers); acetylcholinesterase activity (synaptic and neuronal network dysfunction biomarkers); Raman spectra, proteome, and caffeine. Despite a few studies investigating biomarkers targeting molecular pathways different from alpha-synuclein in Parkinson's disease, these results should be replicated and observed in studies on larger cohorts, considering the potential role of these biomarkers in determining the molecular variance among Parkinson's disease subtypes. Although the need for standardization in sample collection and processing, salivary-based biomarkers studies have reported encouraging results, calling for large-scale longitudinal studies and multicentric assessments, given the great molecular potentials and the non-invasive accessibility of saliva.
PubMed: 38595280
DOI: 10.4103/NRR.NRR-D-23-01677 -
Epigenetics Nov 2020Recent years have seen a surge of methylome-wide association studies (MWAS). We observed that many of these studies suffer from test statistic inflation that is most...
Recent years have seen a surge of methylome-wide association studies (MWAS). We observed that many of these studies suffer from test statistic inflation that is most likely caused by commonly used quality control (QC) pipelines not going far enough to remove technical artefacts. To support this claim, we reanalysed GEO datasets with an improved QC pipeline that reduced test-statistic inflation parameter lambda from the original mean/median of 20.16/15.17 to 3.07/1.14. Furthermore, the mean/median number of methylome-wide significant findings was reduced by 65,688/57,805 loci after more thorough QC. To avoid such false positives we argue for more extensive QC and that reporting the test-statistic inflation parameter lambda become standard for all MWAS allowing readers to better assess the risk of false discoveries.
Topics: Epigenome; Epigenomics; Genome-Wide Association Study; Humans; Reproducibility of Results
PubMed: 32425094
DOI: 10.1080/15592294.2020.1758382 -
Biology of Sex Differences Jul 2020Studies have recently examined the role of epigenetic mechanisms in preeclampsia pathophysiology. One commonly examined epigenetic process is DNA methylation. This...
BACKGROUND
Studies have recently examined the role of epigenetic mechanisms in preeclampsia pathophysiology. One commonly examined epigenetic process is DNA methylation. This heritable epigenetic marker is involved in many important cellular functions. The aim of this study was to establish the association between DNA methylation and preeclampsia and to critically appraise the roles of major study characteristics that can significantly impact the association between DNA methylation and preeclampsia.
MAIN BODY
A systematic review was performed by searching PubMed, Web of Science, and EMBASE for original research articles published over time, until May 31, 2019 in English. Eligible studies compared DNA methylation levels in pregnant women with vs. without preeclampsia. Ninety articles were included. Epigenome-wide studies identified hundreds of differentially methylated places/regions in preeclamptic patients. Hypomethylation was the predominant finding in studies analyzing placental tissue (14/19), while hypermethylation was detected in three studies that analyzed maternal white blood cells (3/3). In candidate gene studies, methylation alterations for a number of genes were found to be associated with preeclampsia. A greater number of differentially methylated genes was found when analyzing more severe preeclampsia (70/82), compared to studies analyzing less severe preeclampsia vs. controls (13/27). A high degree of heterogeneity existed among the studies in terms of methodological study characteristics including design (study design, definition of preeclampsia, control group, sample size, confounders), implementation (biological sample, DNA methylation method, purification of DNA extraction, and validation of methylation), analysis (analytical method, batch effect, genotyping, and gene expression), and data presentation (methylation quantification measure, measure of variability, reporting). Based on the results of this review, we provide recommendations for study design and analytical approach for further studies.
CONCLUSIONS
The findings from this review support the role of DNA methylation in the pathophysiology of preeclampsia. Establishing field-wide methodological and analytical standards may increase value and reduce waste, allowing researchers to gain additional insights into the role of DNA methylation in the pathophysiology of preeclampsia.
Topics: DNA Methylation; Epigenesis, Genetic; Female; Genetic Predisposition to Disease; Humans; Pre-Eclampsia; Pregnancy
PubMed: 32631423
DOI: 10.1186/s13293-020-00313-8 -
Cancers Jan 2024Lung cancer is the leading cause of cancer-related mortality worldwide. Early diagnosis is pivotal for the prognosis. There is a notable overlap between lung cancer and... (Review)
Review
Lung cancer is the leading cause of cancer-related mortality worldwide. Early diagnosis is pivotal for the prognosis. There is a notable overlap between lung cancer and chronic bronchitis, and the potential use of methylated tumor DNA in sputum as a biomarker for lung cancer detection is appealing. This systematic review and meta-analysis followed the PRISMA 2020 statement. A comprehensive search was conducted in Embase, Medline, Web of Science, and the Cochrane Library, using these search strings: Lung cancer, sputum, and methylated tumor DNA. A total of 15 studies met the eligibility criteria. Studies predominantly utilized a case-control design, with sensitivity ranging from 10 to 93% and specificity from 8 to 100%. A meta-analysis of all genes across studies resulted in a summary sensitivity of 54.3% (95% CI 49.4-59.2%) and specificity of 79.7% (95% CI 75.0-83.7%). Notably, two less explored genes (TAC1, SOX17) demonstrated sensitivity levels surpassing 85%. The study's findings highlight substantial variations in the sensitivity and specificity of methylated tumor DNA in sputum for lung cancer detection. Challenges in reproducibility could stem from differences in tumor site, sample acquisition, extraction methods, and methylation measurement techniques. This meta-analysis provides a foundation for prioritizing high-performing genes, calling for a standardization and refinement of methodologies before potential application in clinical trials.
PubMed: 38339257
DOI: 10.3390/cancers16030506