Search Results (665)

Background: Oral diseases such as periodontitis, dental infections, and oral dysbiosis have been increasingly associated with systemic conditions. Emerging evidence suggests a potential relationship between oral health and neurological disorders, including brain abscesses, structural brain alterations, and gliomas. However, the strength and mechanisms of these associations remain incompletely understood. Objective: To systematically review clinical, neuroimaging, genetic, and mechanistic evidence linking oral diseases with brain pathologies. Methods: A systematic literature search was conducted in PubMed, Scopus, Web of Science, and EBSCO, with complementary screening of SciELO, Redalyc, and LILACS databases. Studies evaluating associations between oral diseases (periodontitis, dental infections, caries, or oral microbiota alterations) and neurological outcomes were considered. Eligible study designs included observational clinical studies, Mendelian randomization analyses, neuroimaging studies, and experimental investigations. Seventeen studies met the inclusion criteria. Due to the substantial heterogeneity in study designs, outcomes, and effect metrics, quantitative meta-analysis was not feasible. Findings were therefore synthesized using a structured narrative approach following PRISMA guidelines. Results: Clinical studies consistently identified odontogenic infections as a relevant source of brain abscesses, frequently originating from chronic or clinically silent dental foci. Neuroimaging and genetic studies reported associations between poor oral health indicators and structural brain alterations, including reduced cortical thickness and white matter abnormalities. Experimental investigations suggested potential biological mechanisms involving microbial dissemination, systemic inflammation, and immune modulation. Virulence factors from Porphyromonas gingivalis have been shown to induce inflammatory signaling pathways and immune checkpoint activation in glioma cells. Conclusions: The current evidence suggests a possible association between oral diseases and several brain pathologies. Although causality cannot be established, the findings highlight the importance of oral health as a potentially modifiable factor relevant to neurological health. Further longitudinal and mechanistic studies are required to clarify these relationships. Full article

An inverse correlation between serum vitamin D levels and hidradenitis suppurativa (HS) severity is frequently reported, yet the causal nature and direction of this association remain unresolved. A systematic review was conducted following PRISMA guidelines, identifying 12 relevant studies. A two-sample Mendelian randomization (MR) analysis using the inverse-variance weighted (IVW) method was subsequently performed using genetic instruments for vitamin D from the UK Biobank (n = 417,580) and HS summary statistics from FinnGen (n = 1420). The systematic review confirmed a high prevalence of vitamin D deficiency (<20 ng mL⁻¹) among HS patients (weighted mean 17.90 ng mL⁻¹) and identified inverse correlations between vitamin D levels and disease severity, active lesions, and C-reactive protein (CRP), while supplementation improved clinical outcomes. A null MR estimate consistent with the absence of a detectable average linear causal effect of lifelong genetically predicted 25(OH)D levels on HS risk in the analyzed population was observed. Sensitivity analyses yielded consistent null results with no significant horizontal pleiotropy. The results suggest that hypovitaminosis D is likely a marker of the systemic inflammatory state rather than a direct causative factor. The observed clinical benefits of vitamin D supplementation warrant further interventional studies to define its potential therapeutic role. Full article

Early diagnosis of glaucoma remains challenging due to its asymptomatic onset and multifactorial pathological mechanisms. Growing evidence indicates that metabolic disorders and systemic molecular alterations play significant roles in glaucoma pathogenesis. However, reliable biomarkers and corresponding specific mechanisms remain unclear. In this study, we employed a multi-omics approach that encompassed metabolomics, transcriptomics, and Mendelian randomization to investigate the association between glaucoma and 35 types of blood and urine biomarkers. Metabolic pathway analysis was conducted using pathway enrichment analysis of differentially expressed genes based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Our study indicated that glaucoma contributed to elevated calcium concentration (OR = 1.044, 95% CI: 1.002–1.088, p = 0.039) in blood and urine, mediated by cell membrane calcium channels and calcium release from intracellular storage. Conversely, glucose was found to contribute to high glaucoma risk (OR = 1.324, 95% CI: 1.143–1.533, p = 0.0002), mediated by increased aqueous humor production, elevated intraocular pressure, endoplasmic reticulum stress, and oxidative stress. Validation experiments showed that calcium levels in blood, urine, and retina were elevated in the glaucoma group, and elevated glucose levels significantly reduced the 661W cell viability and induced apoptosis. This study offers new insights into the specific mechanisms linking blood and urine biomarkers to glaucoma, contributing to its prevention and screening. Full article

Background: The senescence-associated hepatic gene set (SHGS) is critical in metabolic-dysfunction-associated steatotic liver disease (MASLD) progression. However, causal links between SHGS genes and liver diseases remain unclear. Methods: Mendelian randomization (MR) was used to explore causal relationships between SHGS genes and liver diseases. Immune infiltration of key genes was analyzed using the CIBERSORT algorithm with GEO database data, validated by single-cell RNA sequencing (scRNA-seq). Virtual docking assessed quercetin’s potential to modulate SHGS proteins and mitigate liver aging. Results: MR analysis identified elevated GBP2 expression as a risk factor for liver fibrosis (OR = 1.904, p = 0.028) but protective against cholangiocarcinoma (OR = 0.548, p = 0.001). Immune profiling and scRNA-seq revealed GBP2’s negative correlation with macrophages in fibrosis and positive correlations with T and NK cells in cholangiocarcinoma. Molecular docking suggested that quercetin indirectly suppresses GBP2 via IRF1, potentially attenuating liver aging. Conclusions: GBP2 might modulate hepatic fibrosis and cholangiocarcinoma. Quercetin may exert antifibrotic effects by indirectly modulating GBP2. Full article

Observational evidence links gut microbiota (GM) dysbiosis to HIV infection; however, the causal relationship between them has not been established. Mendelian randomization (MR) and 16S rRNA gene sequencing analyses were performed to identify gut microbial taxa associated with HIV infection risk. MR analysis results identified 18 gut microbial taxa associated with HIV infection (p values < 0.05), of which 16 taxa were detected in the 16S rRNA gene sequencing data. Following the exclusion of seven taxa with low relative abundance, eight taxa with potential relationships with HIV infection were detected in the 16S rRNA gene sequencing data. Four taxa (Clostridia class, Erysipelotrichales order, Paraprevotella genus, and Parabacteroides distasonis species) showed negative associations and four others (Proteobacteria phylum, Coriobacteriaceae family, Subdoligranulum genus, and Bacteroides ovatus species) showed positive associations with HIV infection risk. The eight taxa effectively distinguished between healthy controls (HCs) and people with HIV (PWH) (p values < 0.05). The area under the curve (AUC) values for the ROC curve analysis ranged from 0.62 to 0.87 for differentiating the HC and PWH groups. Furthermore, the effect of Ruminococcus callidus on HIV infection was partially mediated by hypoxanthine, exhibiting a mediated effect β of 0.17 (p = 0.042). These findings highlight the important role of the GM in HIV infection risk, facilitating future studies exploring better GM regulation strategies against HIV infection risk. Full article

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) is a globally prevalent condition with a complex pathogenesis. While both m6A RNA methylation regulators and gut microbiota have been independently implicated in MASLD, their potential causal interplay remains unexplored. This study aimed to investigate the causal relationships among m6A regulatory genes, gut microbiota, and MASLD, and to assess the mediating role of gut microbiota. Methods: We performed a two-sample Mendelian randomization (MR) analysis using publicly available genome-wide association study (GWAS) data. Genetic instruments for m6A regulators were derived from blood expression quantitative trait loci (eQTL) data. Gut microbiota and MASLD data were obtained from large-scale metagenomic and disease GWAS, respectively. The inverse-variance weighted method was the primary analysis, supplemented by sensitivity and mediation analyses to evaluate potential mediating pathways. Results: Genetically predicted levels of four m6A regulators showed significant causal associations with MASLD risk: ALKBH3 increased risk (OR = 1.17), whereas ALKBH5 (OR = 0.89), CBLL1 (OR = 0.76), and RBM15B (OR = 0.83) were protective. Nineteen gut microbial taxa were causally linked to MASLD. Among these, seven taxa were influenced by the four identified m6A genes. Although no mediation effects reached strict statistical significance, the pathway from ALKBH5 to MASLD via Parabacteroides abundance showed a suggestive indirect effect accounting for 21.9% of the total effect (p = 0.068). Given the limited statistical power of mediation analyses in MR settings, this observation should be interpreted with caution and requires validation in larger, well-powered studies. Conclusions: This MR study provides genetic evidence supporting causal roles of specific m6A regulators in MASLD and suggests that gut microbiota may partially mediate these relationships. The findings highlight a potential “m6A–gut microbiota–liver” axis in MASLD pathogenesis. Full article

This critical integrative review reassesses the lipid paradigm by systematically mapping 380 influential trials and cohort studies on cholesterol, saturated fats, and statins in relation to cardiovascular and cognitive outcomes. The evidence base reveals a nearly even split between studies supporting and challenging LDL-centric causality, alongside pervasive methodological flaws, including reliance on surrogate lipid markers, ecological inferences, residual confounding, and industry-related reporting biases. Trial-generation comparisons and structured risk-of-bias assessment (ROB 2, ROBINS-I) repeatedly show that substantial pharmacological LDL reductions do not consistently yield proportional reductions in myocardial infarction, stroke, or all-cause mortality. Integrating Mendelian randomization with clinical and metabolomic data, the review advances a Critical Window Hypothesis in which LDL is necessary but not sufficient for atherogenesis, exerting dominant causal influence during early and midlife plaque initiation, while inflammatory, oxidative, and hemodynamic factors become primary drivers in advanced disease. Metabolomic studies of extreme longevity and late-life cohorts demonstrate that bile acids, steroid metabolites, and low-glycemic metabolic profiles—not total cholesterol—better predict survival and cognitive preservation, and that higher LDL in the oldest-old often associates with lower mortality and dementia risk. These findings challenge universal LDL-centric policies and support lifestyle medicine strategies prioritizing systemic metabolic optimization over isolated cholesterol targets. Full article

Background: Neuropsychiatric disorders such as Alzheimer’s disease (AD), bipolar disorder (BD), and depression exhibit shared glutamatergic abnormalities, although their upstream molecular mechanisms remain poorly defined. Magnesium (Mg²⁺) serves as a key regulator of N-methyl-D-aspartate (NMDA) receptor function; however, the role of Mg²⁺ transporters, particularly SLC41A1, has not been systematically investigated. As NMDA receptor dysregulation contributes to emotional and cognitive impairments, elucidating Mg²⁺-NMDA signaling may enable the development of novel therapeutic strategies. Methods: We integrated Mendelian randomization, locus colocalization, human brain transcriptomics, functional enrichment, and co-expression analyses to determine whether SLC41A1 functions as a cross-disorder molecular driver. In addition, in vitro electrophysiological experiments using field potential recordings in hippocampal Schaffer-CA1 synapses were conducted to validate its functional role in NMDA receptor-mediated synaptic transmission. Results: Genetically elevated SLC41A1 expression increased the risk of AD, BD, depression, and alcohol dependence, with strong colocalization analyses supporting shared causal variants. Transcriptomic profiling revealed SLC41A1 upregulation in AD and BD, with enrichment in magnesium transport, mitochondrial function, and synaptic signaling pathways. Co-expression networks across GTEx brain regions demonstrated strong correlations with NMDA-related genes (e.g., GRINA, CAMK2G, GRIN2C). Under NMDAR-selective recording conditions, both imipramine treatment and SLC41A1 knockdown significantly reduced NMDAR-mediated fEPSP amplitudes, supporting a role for SLC41A1 in regulating NMDA receptor-dependent synaptic responses. Conclusions: This study identifies SLC41A1 as a magnesium-centered, transdiagnostic therapeutic target that links Mg²⁺ homeostasis to NMDA-dependent synaptic dysfunction. These findings provide a mechanistic foundation for developing SLC41A1-modulating or magnesium-based therapeutic approaches for mood and cognitive disorders. Full article

Atopic dermatitis (AD) is a chronic inflammatory skin disease with a complex and highly polygenic genetic architecture, in which immune-mediated mechanisms play a central role. Here, we integrated single-cell cis-expression quantitative trait loci from 14 immune cell types with AD GWAS summary statistics using a two-sample Mendelian Randomization (MR) framework to resolve cell-specific genetically mediated transcriptional effects. We identified 303 significant cell-specific gene–trait associations with limited overlaps across cell types. A multi-step prioritization strategy refined these findings to 35 genes across all 14 cell types. A comparison with whole blood cis-eQTLs revealed a limited concordance, suggesting an attenuation of cell-specific regulatory effects in bulk transcriptomic approaches. Intersecting single-cell and bulk evidence identified 22 high-confidence genes with a relatively independent mechanism of action. Integrative annotation implicated several immune-relevant and druggable genes, including IL2RA, with distinct cell-specific effects. Our findings demonstrate diverse mechanisms of risk genes for AD at the single-cell level that act across immune cell states and pathways, with implications for therapeutic interventions. Full article

Autism spectrum disorder (ASD) frequently co-occurs with malnutrition and gut dysbiosis, yet the underlying mechanisms remain poorly understood. Herein, this cross-sectional study first profiles dietary intake differences using dietary records from 210,874 participants (ASD = 232; non-ASD = 210,642; median age = 56.18) from the UK Biobank (UKB). Second, a bi-directional Mendelian Randomization (MR) approach serves to dissect relationships between ASD genetic susceptibility and dietary preferences by leveraging genome-wide association metadata from the iPSYCH-PGC (ASD) and UKB (dietary intake/food-liking traits). The same strategy is implemented to identify ASD-associated gut microbial species. Mediation analyses further assess the role of gut microbiota in the association between ASD and dietary preferences. Subjects with ASD exhibit higher consumption of cheese, processed meat, and oily fish, alongside lower intake of fruits, and demonstrate a preference for high-fat/salt and energy-dense foods. Additionally, the depletion of Turicibacter, Streptococcus, and Lachnospiraceae NK4A136 was causally related with ASD (all false discovery rate < 0.05; β = −0.15, β = −0.10, β = −0.093, respectively), which significantly mediates the ASD-associated elevated preference for high-fat/salt foods. In conclusion, ASD is associated with specific dietary preferences, likely mediated via gut microbiota, highlighting the future potential of gut microbiome-based therapeutics to modify eating disorders for ASD. Full article

Multiple myeloma (MM) is a clonal plasma cell neoplasm characterized by autonomous immunoglobulin overproduction. Despite associations between serum metabolites and MM, causal mechanisms remain unclear. Here, we employed bidirectional Mendelian randomization (MR) using 452 serum metabolites to elucidate causal associations with MM risk. The inverse variance-weighted (IVW) method was prioritized, complemented by MR-Egger and weighted median (WM) analyses to address horizontal pleiotropy. Sensitivity analyses—including Cochran’s Q test, MR-Egger intercept evaluation, and leave-one-out (LOO) robustness checks—confirmed result stability. Pathway enrichment was performed using MetaboAnalyst 6.0. RNA-seq data were integrated to identify transcriptional regulators and signaling pathways mediating serum metabolite-driven MM. Among 21 metabolites significantly associated with MM, 8 exhibited protective inverse correlations, while 13 showed risk-enhancing effects. Sensitivity analyses further confirmed the validity of the observed relationships, while bidirectional MR confirmed no reverse causality. Pathway enrichment highlighted valine/leucine/isoleucine biosynthesis and biotin metabolism as pivotal pathways. Integrating transcriptomic data revealed 11 overlapping genes enriched in metal ion transmembrane transporter activity and glycosaminoglycan biosynthesis—chondroitin sulfate/dermatan sulfate. This study established a causal relationship between specific serum metabolites and MM and revealed that key genes may affect the development of MM through metabolic-epigenetic crosstalk, providing preliminary insights into potential therapeutic targets. Full article

Euphorbia helioscopia L. (Zeqi, ZQ) is a traditional Chinese herb used to treat various tumors, but its molecular mechanisms against hepatocellular carcinoma (HCC) remain unclear. This study aims to elucidate the anti-HCC mechanisms of ZQ using chemical profiling, bioinformatics, Mendelian randomization (MR), and experimental validation. A total of 104 compounds were identified from ZQ, with 18 targeting HCC-related proteins. Bioinformatics and MR analyses revealed PTK2 as a core target associated with HCC risk. ZQ significantly suppressed H22 tumor growth in male ICR mice and inhibited PTK2/PI3K/AKT phosphorylation. Molecular docking and dynamics simulations confirmed stable binding between key ZQ compounds and PTK2. These results suggest that ZQ exerts anti-HCC effects through PTK2 inhibition and modulation of the PI3K/AKT pathway, supporting its potential as a multi-targeted therapeutic for HCC. Full article

Background: Although elevated triglyceride (TG) levels are consistently associated with hypertension in observational studies, whether TGs have a causal effect on hypertension remains uncertain, and evidence in East Asian populations is limited. Methods: We analyzed 2159 Korean adults (20–86 years) whose individual-level genetic and phenotypic data were obtained from a cross-sectional health check cohort. Candidate TG-associated genetic variants were identified using genome-wide association analysis and evaluated as instrumental variables (IVs). An individual-level, two-stage IV Mendelian randomization (MR) framework was applied to assess the potential effect of TGs on hypertension, alongside conventional observational analyses using logistic regression. Results: Three candidate TG-associated single-nucleotide polymorphisms (SNPs)—rs78115082 (TRPC7), rs117867615 (TTLL1), and rs34463296 (LINC03019)—were identified and combined to construct a weighted genetic risk score (GRS). Although all the instruments met the conventional strength criteria (F statistics > 10), they explained only a modest proportion of the variance in TG levels (partial R², 0.008–0.020). Observational analyses showed a strong positive association between TG levels and hypertension (crude odds ratio [OR] = 2.12; 95% confidence interval [CI]: 1.76–2.54; adjusted OR = 1.43; 95% CI: 1.16–1.75). In contrast, MR estimates based on individual SNPs and the GRS were directionally positive but statistically nonsignificant, with wide CIs crossing the null, indicating limited precision. Conclusions: In this Korean cohort, observational analyses demonstrated a robust association between TG levels and hypertension, whereas individual-level MR provided inconclusive genetic evidence for a causal effect under the available instruments. The difference between the observational and genetic estimates is compatible with the finding that TG levels reflect broader cardiometabolic dysregulation rather than acting as an isolated causal determinant of hypertension. These findings underscore the need for larger studies with stronger, externally derived instruments to refine the causal inference in East Asian populations. Full article

Background: Lone atrial fibrillation (AF) is characterized by the absence of discernible risk factors, yet its long-term prognostic implications remain unclear. We evaluated genetic predisposition to lone AF and conducted a Mendelian randomization (MR) study to assess its causal effect on cardiovascular outcomes. Methods: A genome-wide association study (GWAS) for lone AF, along with common AF was conducted using UK Biobank data. Lone AF was defined as AF occurring without clinical risk factors. Summary-level data for cardiovascular phenotypes were obtained from publicly available GWAS datasets and the causal effects were estimated using MR. Results: We identified 36 single-nucleotide polymorphisms associated with lone AF, including two novel loci. In MR analyses, lone AF was significantly associated with an increased risk of stroke (odds ratio [OR] 2.62, 95% confidence interval [CI] 2.14–3.22) and heart failure (HF) (OR 2.55, 95% CI 2.14–3.04). The associations with coronary artery disease (CAD) (OR 0.90, 95% CI 0.73–1.10) and cardiac death (OR 1.32, 95% CI 0.99–1.77) were not significant. MR analyses of common AF also demonstrated significant associations with stroke (OR 1.86, 95% CI 1.69–2.04) and HF (OR 1.71, 95% CI 1.59–1.84), though the effect sizes were smaller compared to those of lone AF. Conclusions: Genetic predisposition to lone AF is associated with more than a twofold increase in the risk of stroke and HF. However, no clear association was observed between lone AF and CAD or cardiac death. Full article

Background: Oxidative stress (OS) has been widely implicated in pathophysiology of major psychiatric disorder. However, establishing robust causal links and delineating the specific molecular mechanisms involved continue to pose significant research challenges. Methods: We performed a multi-omics analysis focusing on 817 oxidative stress-related genes (OSGs) in major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia (SCZ). We applied summary data-based Mendelian randomization (SMR), integrating large-scale genome-wide association studies for MDD, BD, and SCZ with quantitative trait loci datasets from both blood and brain tissues, including measures of DNA methylation, gene expression, and protein abundance. Results: Multi-omics integration yielded supportive evidence across blood and brain tissues implicating ACE and ACADVL in SCZ, where genetically predicted increases in their methylation, expression, and protein abundance were associated with reduced disease risk. IGF1R was associated with bipolar disorder (BD) risk in blood-specific analyses. Brain-specific analyses further nominated ENDOG as a candidate gene for SCZ. Single-cell SMR indicated that increased ENDOG expression was associated with higher SCZ risk in astrocytes, CD4⁺ naïve T cells, CD8⁺ effector T cells, and natural killer cells, suggesting a potential immune–brain interaction. Conclusions: This study provides multi-level genetic evidence supportive of a potential causal role for specific OSGs in major psychiatric disorders. We identify ACE, ACADVL, IGF1R, and ENDOG as candidate genes for further investigation, offering insights into epigenetic and transcriptional mechanisms that could inform future research on therapeutic targets. Full article