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PubMed2026

Genetically proxied circulating PD-1/PD-L1 levels and broadly defined myocarditis: A bidirectional Mendelian randomization study with exploratory lipidomic analyses.

Myocarditis is an inflammatory myocardial disease with potentially severe outcomes. Programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1) regulate immune tolerance, but the association between lifelong genetically proxied circulating PD-1/PD-L1 levels and broadly defined myocarditis remains uncertain. We investigated these associations and explored related plasma lipid species. We conducted bidirectional 2-sample Mendelian randomization using proteomic genome-wide association data from the UK Biobank Pharma Proteomics Project and INTERVAL. FinnGen Release 10 was the primary broadly defined myocarditis outcome, and an independent myocarditis genome-wide association study (GCST90018882) provided outcome-level validation. Complementary estimators, heterogeneity and pleiotropy diagnostics, influence analyses, MR-RAPS, and supportive meta-analyses were performed. Associations with 179 plasma lipid species were examined in exploratory analyses. Higher genetically proxied circulating PD-L1 was inversely associated with broadly defined myocarditis in UKB-PPP (odds ratio [OR] 0.834, 95% confidence interval [CI] 0.698-0.995; P = .0441), and the independent INTERVAL analysis yielded a concordant inverse estimate (OR 0.619, 95% CI: 0.434-0.883; P = .0083); no clear association was observed for PD-1. The MR-RAPS estimate retained the inverse direction; estimates against the independent broadly defined myocarditis dataset were also inverse, and supportive meta-analyses across protein and outcome sources yielded inverse pooled estimates. Reverse MR did not support effects of broadly defined myocarditis liability on circulating PD-1 or PD-L1. Exploratory lipid analyses identified nominal associations requiring confirmation. Higher genetically proxied circulating PD-L1 may be associated with a lower risk of broadly defined myocarditis, supporting further investigation of PD-L1-related immune regulation. These findings do not directly estimate the effects of pharmacologic PD-1/PD-L1 blockade. The lipid findings are hypothesis-generating.

Myocarditis↗

PubMed2024

Dissecting the association between blood pressure traits, hypertension, antihypertensive medications and epilepsy: A Mendelian randomization study.

BACKGROUND: Observational studies suggest that hypertension and epilepsy have a high co-occurrence, and antihypertensive medications may have impacts on the prevention and treatment of epilepsy. However, the directionality of causation between them is elusive. METHOD: By leveraging genome-wide association studies (GWAS) summary data of each trait, we firstly performed bidirectional univariate Mendelian randomization (UVMR) to assess the strength and direction of the associations between pairs of traits, then multivariate MR (MVMR) was conducted to adjust for potential confounders in causalities. Cochran's Q statistics, leave-one-out analysis, MR-Egger regression and MR-Pleiotropy Residual Sum and Outlier methods (MR-PRESSO) were employed to evaluate the robustness of the results. Drug target MR was proceeded to assess the association between five classes of first-line antihypertensive medications and epilepsy. Specifically, single nucleotide polymorphisms (SNPs) extracted from GWAS data on systolic blood pressure (SBP)/diastolic blood pressure (DBP), along with expression quantitative trait loci (eQTL) were utilized as proxies for antihypertensive medications, respectively. RESULTS: Forward UVMR results provided evidence that genetically predicted blood pressure traits and hypertension have causal effects on epilepsy, while reverse UVMR indicated no causal impacts of epilepsy on blood pressure traits or hypertension. The sensitivity analysis results were robust. The causalities between DBP, hypertension and epilepsy remained remarkable after adjustment by MVMR. Inverse-variance-weighted MR (IVW-MR) yielded evidence of positive association only between Beta-Blockers target genes based on DBP GWAS screening and epilepsy. Summary-data-based MR (SMR) identified a positive correlation between Beta-Blockers target gene ADRA1D and epilepsy risk. CONCLUSIONS: Hypertension has a causal effect on epilepsy and managing DBP in patients with hypertension through Beta-Blockers may help prevent epilepsy.

Humans↗

PubMed2026

The Mediating Role of Immune Cells in the Genetically Predicted Relationship between Gut Microbiota and Puerperal Sepsis: A Mendelian Randomization Study.

INTRODUCTION: The causal relationship between gut microbiota and puerperal sepsis (PS) remains unclear, and there is a lack of in-depth research regarding the potential mediating role of immune cells in this context. OBJECTIVE: This study aims to investigate the causal relationship between gut microbiota and PS using Mendelian randomization (MR) analysis and to assess the mediating effects of immune cells on the risk of PS onset through mediation analysis. MATERIALS AND METHODS: We selected data from large-scale genome-wide association studies (GWAS) involving 473 gut microbiota species, 731 immune cell phenotypes, and PS datasets. Univariate MR (UVMR) analysis was employed to explore the causal relationship between gut microbiota and PS, with the primary statistical method being inverse variance weighting (IVW). Multiple statistical models were applied for sensitivity analysis to minimize the confounding effects of horizontal pleiotropy and heterogeneity. Subsequently, a two-step mediation MR analysis was conducted to evaluate whether immune cells mediate the relationship between gut microbiota and PS. RESULTS AND DISCUSSION: Analysis using various statistical models indicated that 11 gut microbiota species (e.g., Azorhizobium, Bacillus velezensis, CAG-245 sp000435175, Lentimicrobiaceae, and Providencia) exhibited a causal relationship with PS. Further reverse causal analysis between PS and gut microbiota ruled out the possibility of reverse causality. The two-step mediation MR analysis demonstrated that the percentage of IgD-CD27- B cells (10.26%) and CD62L- monocytes (17.29%) partially mediated the effect of CAG-245 sp000435175 on PS risk. CONCLUSION: This study provides evidence of a causal relationship between the abundance of certain gut microbiota species and PS, while also revealing a potential mediating role of immune cells. These findings offer valuable theoretical insights into personalized treatment strategies and the development of novel diagnostic biomarkers for PS.

Humans↗

PubMed2026

Dissecting the shared genetic architecture between migraine subtypes and cardiovascular diseases: a multi-layered genomic analysis.

BACKGROUND: Epidemiological studies have linked migraine to an increased risk of cardiovascular disease (CVD); however, the shared genetic basis and putative causal relationships between migraine subtypes and cardiovascular traits remain poorly understood. METHODS: Leveraging large-scale GWAS summary statistics for migraine phenotypes (overall migraine, migraine with aura [MA], and migraine without aura [MO]) from FinnGen R12, along with seven cardiovascular diseases from publicly available consortia, we conducted a multi-layered genetic analysis. This integrative framework encompassed genetic correlation [linkage disequilibrium score regression (LDSC) and high-definition likelihood (HDL)], cross-trait meta-analysis (CPASSOC and PLACO), Bayesian colocalization, summary-data-based Mendelian randomization (SMR) using GTEx v8 eQTL data, and bidirectional two-sample Mendelian randomization (MR). RESULTS: Significant genetic correlations were identified between migraine and multiple cardiovascular traits, with hypertension and coronary artery disease (CAD) showing the most robust associations. MA exhibited broader genetic overlap with cardiovascular diseases than MO, including a notably stronger correlation with ischemic stroke, whereas MO demonstrated a stronger correlation with hypertension. Cross-trait meta-analysis identified 160 pleiotropic loci across 17 of 21 trait pairs. Colocalization analysis confirmed 32 loci harboring shared causal variants, mapped to 13 candidate genes, of which 7 (PHACTR1, LRP1, SOX7, ABO, FHOD3, MEI1, XKR6) were further validated by SMR as exhibiting tissue-specific regulatory effects. Among these, PHACTR1 displayed the broadest pleiotropic profile across migraine phenotypes and vascular diseases. After MR-PRESSO outlier removal, bidirectional MR identified 10 MR-supported associations, two of which (genetic liability to hypertension on overall migraine, and CAD on MA) survived Bonferroni correction, all free of detectable horizontal pleiotropy. Genetic liability to hypertension was associated with increased migraine risk (OR = 1.90, 95% CI 1.25-2.90, P = 2.64 × 10⁻³), atherosclerotic diseases showed subtype-specific effects (inverse for MO, positive for MA), and, in the reverse direction, migraine was associated with increased ischemic stroke risk. CONCLUSIONS: This study provides a comprehensive and systematic characterization of the shared genetic architecture between migraine subtypes and cardiovascular diseases. By identifying pleiotropic genes and bidirectional putative causal relationships with subtype-specific patterns, our findings carry implications for the development of targeted therapeutics and subtype-specific cardiovascular risk stratification.

Humans↗

PubMed2002

Homozygous Tsix mutant mice reveal a sex-ratio distortion and revert to random X-inactivation.

Tsix controls X-chromosome inactivation (XCI) by blocking the accumulation of Xist RNA on the future active X chromosome. Deleting Tsix on one X chromosome (X(Delta)X) skews XCI toward the mutated X chromosome in the female soma. Here I have generated homozygous Tsix-null mice (X(Delta)X(Delta)) to test how deleting the second allele affects the choice of XCI. Homozygosity leads to extremely low fertility and reveals two previously unknown non-mendelian patterns of inheritance. First, the sex ratio is skewed against female births so that one daughter is born for every two to three sons. Second, the pattern of XCI unexpectedly returns to random in surviving X(Delta)X(Delta) mice. Thus, with respect to choice, mutation of Tsix yields a phenotypic abnormality in heterozygotes but not homozygotes. To reconcile the paradox of female loss with apparent reversion to random choice, I propose that deleting both Tsix alleles results in chaotic choice and that randomness in X(Delta)X(Delta) survivors reflects a fortuitous selection of distinct X chromosomes as active and inactive.

Animals↗

PubMed2026

Human skin microbiota and postpartum depression: A bidirectional Mendelian randomization study.

Postpartum depression (PPD) is a common mental health disorder after childbirth. Although microbiome research in PPD has mainly focused on the gut, the role of skin microbiota remains unclear. We used Mendelian randomization (MR) to assess potential causal associations between skin microbiota and PPD. A bidirectional 2-sample MR analysis used genome-wide association study (GWAS) summary statistics. Genetic instruments for skin microbial features were obtained from a published skin microbiota GWAS, and PPD data were derived from 67,205 mothers (7604 cases, 59,601 controls). Instruments were selected at P <1 × 10-5, linkage disequilibrium-clumped, harmonized, and filtered for weak instruments (F statistic <10). Because this microbiome threshold is exploratory, Benjamini-Hochberg false discovery rate correction was applied within taxonomic levels. The inverse-variance weighted method was primary, complemented by weighted median and mode-based methods. Heterogeneity, pleiotropy, and outliers were assessed using Cochran Q, MR-Egger intercept, and MR-PRESSO. Three skin microbial taxa showed nominal associations with PPD. Higher genetically predicted Acinetobacter on the dorsal forearm (dry skin; 9 single nucleotide polymorphisms [SNPs]; mean F = 22.12) and Proteobacteria in the antecubital fossa (moist skin; 6 SNPs; mean F = 23.44) were associated with increased PPD risk, whereas Betaproteobacteria in the antecubital fossa (11 SNPs; mean F = 21.54) was associated with decreased risk. Associations were directionally consistent, with no substantial heterogeneity or horizontal pleiotropy. After multiple-testing assessment, the findings were exploratory rather than definitive. Reverse MR did not support an effect of PPD on the identified skin microbiota. This MR study provides exploratory genetic evidence linking specific skin microbial features to PPD risk. The findings extend microbiota-related hypotheses beyond the gut microbiome but require validation in larger microbiome GWAS datasets, longitudinal cohorts, and mechanistic studies before clinical or causal conclusions are drawn.

Humans↗

PubMed2026

Myeloid Dendritic Cell Counts and Coronary Heart Disease: a Bidirectional Mendelian Randomization Study.

BACKGROUND: Coronary heart disease (CHD) remains a leading cause of morbidity and mortality worldwide, with immune and inflammatory mechanisms playing important roles in its pathogenesis. Dendritic cells (DCs) are key regulators of immune responses; however, the relationship between specific DC subsets and CHD risk remains incompletely understood. METHODS: This study conducted a bidirectional two-sample Mendelian randomization (MR) analysis using publicly available genome-wide association study (GWAS) summary statistics to investigate the potential associations between circulating dendritic cell traits and CHD. Genetic instruments for myeloid dendritic cells (Myeloid DCs) and plasmacytoid dendritic cells (Plasmacytoid DCs), including both absolute counts and relative proportions, were obtained from immune cell GWAS datasets. Summary statistics for CHD were derived from a large European-ancestry population. Multiple MR methods were applied, and sensitivity analyses were performed to assess the robustness of the findings and potential pleiotropic effects. RESULTS: Nominal associations between genetically predicted Myeloid DC counts and CHD risk were observed in the MR-Egger and weighted median analyses, whereas the inverse variance weighted analysis demonstrated no significant association. These nominal associations did not remain statistically significant after correction for multiple testing. No significant associations were observed for Plasmacytoid DC counts or for the relative proportions of either DC subset. Reverse MR analyses were inconclusive due to wide confidence intervals, precluding meaningful inference regarding a causal effect of CHD on DC-related traits. Sensitivity analyses revealed no substantial heterogeneity or horizontal pleiotropy. CONCLUSIONS: This bidirectional MR study explored the potential relationships between circulating dendritic cell traits and CHD risk. Although nominal associations involving Myeloid DC counts were observed in secondary MR analyses, no robust evidence supporting an association remained after correction for multiple testing. Further studies using larger datasets and functional approaches are warranted to clarify the role of dendritic cells in CHD.

Humans↗

PubMed2026

Constipation and Psychiatric Disorders: A Bidirectional Mendelian Randomization Study.

BACKGROUND: Observational studies have shown a link between constipation (CN) and psychiatric disorders, including Schizophrenia (SP), Bipolar disorder (BD), Schizoaffective disorder (SD), and Parkinson's disease (PD). However, it is still unknown whether CN affects the occurrence and development of psychiatric disorders or whether psychiatric disorders cause the occurrence and development of CN. Therefore, this study used Mendelian randomization (MR) analysis to evaluate the relationship between CN and psychiatric disorders. METHOD: We used genome-wide association studies (GWAS) to assess the relationship between constipation (N = 411, 623) and four psychiatric disorders, including SP ( N = 77, 096), BD (N = 51, 710), SD ( N = 210, 962), PD (N = 482, 730 ), using bidirectional MR analysis. Inverse variance weighting (IVW), MR Egger (ME) and Weighted median (WM) were used as causal analysis methods. Cochran's Q test, funnel plot, MR Egger intercept test and Leave.one.out analysis were used to detect sensitivity. Confounding factors were analyzed and eliminated by LDtrait to avoid influencing the final MR Analysis result. RESULTS: The results of positive MR analysis indicated that there was no evidence of influence of constipation on SP (OR 1.043, 95%CI 0.946 - 1.149, P value = 0.398), BD (OR 1.114, 95%CI 0.995 - 1.248, P value = 0.062), SD (OR 0.934, 95%CI 0.674 - 1.294, P value = 0.682) and PD (OR 1.118, 95%CI 0.918 - 1.361, P value = 0.269) under gene prediction. Reverse MR analysis suggested that SP (OR 1.030, 95% CI 1.001-1.060, P value = 0.042) had a causal relationship with constipation. BD (OR 0.993, 95% CI 0.962-1.025, P value = 0.664), SD (OR 1.021, 95% CI 0.984-1.059, P value = 0.265) and PD (OR 1.004, 95% CI 0.974-1.035, P value = 0.790) were not associated with CN. CONCLUSION: There was a positive association between SP and CN. CN may have no exact causal relationship with BD, SD and PD, and the interaction mechanism between these diseases needs to be further explored.

Constipation↗

PubMed2026

Genetic trade-offs in fertility and longevity explain the maintenance of disease-associated alleles in humans.

Genetic variants that increase the risk for complex diseases persist in human populations, despite adverse effects on health and longevity. Life-history theory predicts that such alleles can be maintained by trade-offs arising from pleiotropy, yet direct genomic evidence has been limited. We asked whether disease-associated variants persist because they enhance reproduction, despite costs to health and lifespan. By analysing genome-wide data across 62 diseases, longevity and fertility, we show that disease-risk alleles are, on average, associated with reduced longevity and increased fertility. Moreover, the subset of alleles that increase both fertility and disease risk appear to have been favoured by natural selection over the past 50,000 years. Using Mendelian randomization, we detect a causal effect of genetic liability to disease on longevity, but no robust evidence for a causal effect on fertility; importantly, these estimates remain stable after adjusting for socioeconomic factors. At the individual level, we compared offspring numbers between affected and unaffected individuals with high polygenic disease risk. For most diseases, affected individuals had more children than unaffected ones. But for early-onset diseases, the pattern reverses, indicating reproductive costs of early morbidity. Together, these results support antagonistic pleiotropy and help explain the persistence of disease-risk alleles in human populations.

Humans↗

PubMed2025

Mendelian randomization underscores the importance of clinical nursing in mitigating anxiety and panic attack risks among low-educated populations.

Considering the complex and underexplored interplay between educational attainment (EA) and the prevalence of anxiety and panic attacks, which carries significant societal implications, we have designed a two-sample Mendelian randomization (MR) study. The primary objective of this research is to elucidate the causal relationship between education level and the risk of anxiety and panic attacks, thereby providing novel insights for clinical and nursing strategies. Our study adheres to the STROBE-MR guidelines and employs a classical two-sample MR analysis to investigate the causal relationship between EA (exposure) and the occurrence of anxiety/panic attacks (outcome). The data for 8 education-related phenotypes, along with anxiety and panic attack outcomes, were sourced from European population-based Genome-wide association studies databases. To ensure robustness, we applied 5 distinct MR analytical methods, supplemented by comprehensive sensitivity analyses, heterogeneity assessments, and evaluations of reverse causality bias to uphold rigorous quality control standards. Our findings, robust across various MR methods and consistent after inverse variance-weighted and false discovery rate (FDR) corrections, indicate a significant association between lower EA and an increased risk of anxiety or panic attacks. Specifically, individuals with no formal qualifications exhibited a higher risk (P-value = .005, OR = 1.017, 95% CI = 1.005-1.029, FDR = 0.011). In contrast, higher levels of education were associated with a reduced risk: College or University degree (P-value < .01, OR = 0.989, 95% CI = 0.984-0.995, FDR = 0.0007), EA (P-value < .01, OR = 0.999, 95% CI = 0.998-0.9995, FDR = 0.0009), and A levels/AS levels or equivalent (P-value = .011, OR = 0.988, 95% CI = 0.978-0.997, FDR = 0.019). These conclusions were consistently supported by at least 4 MR methods and successfully passed all quality control checks. Our study demonstrates a negative correlation between years of education and the risk of anxiety and panic attacks, suggesting that clinical nursing and patient education efforts should prioritize tailored psychological support and patient communication for individuals with lower EA. This population warrants enhanced attention and more compassionate care to mitigate their elevated risk of anxiety-related disorders.

Humans↗

PubMed2025

Circulating inflammatory proteins and osteomyelitis: A bidirectional Mendelian randomization and colocalization analysis.

Circulating inflammatory proteins (CIPs) have been implicated in the progression of osteomyelitis (OM); however, whether these proteins play a causal role or are merely a consequence remains unclear. This study aimed to assess the causal relationships between CIPs and OM using a bidirectional 2-sample Mendelian randomization (MR) approach. MR analyses were performed using genome-wide association study summary statistics for 91 inflammation-related proteins (n = 14,824) and OM (1881 cases and 3,91,037 controls). The inverse variance weighted method was used as the primary analytical approach, supplemented by MR-Egger, weighted median, simple mode, and weighted mode methods. Sensitivity analyses were conducted to evaluate heterogeneity, horizontal pleiotropy, and robustness. Colocalization analysis was applied to identify shared causal variants, and pathway enrichment analysis was used to explore underlying biological mechanisms. Forward MR analysis revealed that elevated levels of tumor necrosis factor-beta (TNF-β) were significantly associated with increased OM risk (odds ratio [OR] = 1.132; 95% confidence interval [CI]: 1.052-1.217; false discovery rate [FDR] = 0.027). Conversely, decreased levels of osteoprotegerin (OR = 0.772; 95% CI: 0.671-0.889; FDR = 0.015) and adenosine deaminase (OR = 0.811; 95% CI: 0.736-0.894; FDR < 0.001) were associated with increased OM risk. Reverse MR analysis identified increased levels of interleukin-15 receptor alpha, C-X-C motif chemokine ligand 1, fms-related tyrosine kinase 3 ligand, interleukin-20, interleukin-10 (IL10), C-C motif chemokine ligand 19, and CXCL6 as being significantly associated with OM susceptibility (all FDR < 0.05). Colocalization analysis provided strong evidence for a shared causal variant between TNF-β and OM (posterior probability for hypothesis 4 = 0.999). Enrichment analyses indicated involvement of implicated proteins in Toll-like receptor signaling and T-helper 17 cell differentiation pathways. This study identified several CIPs - including TNF-β, osteoprotegerin, and adenosine deaminase - as potentially causal in OM development. These findings highlight promising targets for future immunomodulatory therapies aimed at preventing or mitigating osteomyelitis.

Humans↗

PubMed2026

Hyperthyroidism Is Genetically Associated With Reduced Risk of Parkinson's Disease: A Mendelian Randomization Analysis.

Parkinson's disease (PD) is a progressive neurodegenerative disorder whose aetiology involves an intricate interplay of genetic, immune, metabolic and environmental factors. Endocrine dysfunction-particularly disturbances of thyroid hormone signalling-has been proposed as a contributor to neurodegeneration, but conventional observational studies have produced inconsistent results, and prior Mendelian randomization (MR) work has largely focused on continuous thyroid biomarkers rather than clinically defined hyperthyroid disease states. To clarify this relationship, we performed a two-sample bidirectional and multivariable MR (MVMR) analysis using large-scale genome-wide association study (GWAS) summary statistics from the FinnGen and IEU Open GWAS databases (European ancestry). Single-nucleotide polymorphisms (SNPs) reaching genome-wide significance (p < 5 × 10-8) for Graves' disease and thyrotoxicosis with diffuse goitre served as instrumental variables. The inverse-variance weighted (IVW) method was the primary analysis, complemented by MR-Egger, weighted median, weighted mode and simple mode estimators, and MVMR adjusted for smoking, alcohol consumption, and body mass index (BMI). In forward analyses, genetically proxied Graves' disease (OR = 0.942, 95% CI 0.901-0.985, p = 0.008) and thyrotoxicosis with diffuse goitre (OR = 0.929, 95% CI 0.879-0.982, p = 0.009) were associated with a lower risk of PD, whereas reverse analyses showed no significant effect of genetic liability to PD on either thyroid trait. The inverse associations remained stable across MVMR models, and sensitivity analyses (Cochran's Q, MR-Egger intercept, MR-PRESSO, leave-one-out) showed no evidence of heterogeneity or horizontal pleiotropy. Collectively, these findings provide genetic evidence consistent with a protective relationship between hyperthyroid disease states and PD, independent of major lifestyle confounders. By focusing on clinically defined hyperthyroid entities rather than continuous thyroid indices, our study complements prior MR work and highlights the thyroid-brain axis-encompassing thyroid hormone signalling and autoimmune-mediated immune modulation-as a biologically plausible and potentially modifiable contributor to PD risk that warrants further mechanistic and translational investigation.

Humans↗

PubMed2026

A Mendelian Randomization Study of Immune Cell Traits and Plasma Metabolites in Hashimoto's Thyroiditis.

Hashimoto's thyroiditis (HT) is an autoimmune disorder of the thyroid. While immune cells are implicated in its pathogenesis, their specific roles have yet to be fully clarified. A two-sample Mendelian randomization (MR) analysis was conducted integrating genome-wide association study (GWAS) summary statistics from large public datasets for immune cell traits (ebi-a-GCST90001391 to ebi-a-GCST90002121), plasma metabolites (GCST90199621-9020102), and HT (ebi-a-GCST90018855). Causal effects were estimated using inverse-variance weighted (IVW) methods, with MR-Egger, weighted median, and leave-one-out analyses to assess pleiotropy and robustness. Bidirectional and mediation MR analyses were further applied to test directionality and identify potential metabolite-mediated pathways. CD3⁺CD4⁺CD25⁺CD39⁺Treg cells were quantified in peripheral blood samples using flow cytometry. Isovalerylcarnitine (C5) was measured by liquid chromatography tandem mass spectrometry. IVW analysis identified 32 immune cell phenotypes significantly associated with HT risk (P < 0.05 after FDR correction). Reverse MR analysis demonstrated that HT was positively causally linked with 2 immune characteristics, while 4 immune characteristics (all P < 0.05) were inversely associated with HT. Sensitivity analyses revealed no horizontal pleiotropy or heterogeneity. Additionally, the IVW method preliminarily identified 9 plasma metabolites as causally related to HT, including risk-enhancing C5 (OR = 1.120, 95% CI: 1.032-1.215, P = 0.006) and protective ergothioneine (OR = 0.958, 95% CI: 0.927-0.990, P = 0.010). Two-step MR mediation identified C5 as a candidate mediator connecting CD3⁺ CD39⁺ Treg to HT (mediation proportion 8.89%, 95% CI: 2.34%-15.4%, P = 0.008). Flow cytometry elevated CD39⁺Treg levels and plasma C5 in HT patients, with C5 positively correlated with CD39⁺Treg cells proportion. This study establishes novel causal links between immune cell phenotypes and HT, and highlights plasma metabolites, particularly C5, as potential mediators in HT pathogenesis. These findings deepen mechanistic understanding of autoimmune thyroid disease and may guide future biomarker and therapeutic target discovery.

Humans↗

PubMed2025

Causal relationships between antibody-mediated immune responses and acute pancreatitis: Evidence from a genetic study.

Certain specific antibody-mediated immune responses may be associated with acute pancreatitis (AP), but their causal relationship remains uncertain. Therefore, we used bidirectional two-sample Mendelian randomization (MR) to investigate their causal link and potential mediation by inflammatory cytokines. Data for this study were sourced from a large-scale Genome Wide Association Study (GWAS) communal data pool. To explore the causality between antibody-mediated immune responses and AP, we performed two-sample bidirectional MR analyses using 5 approaches: inverse-variance weighted (IVW), MR-Egger, weighted mode, weighted median, and simple mode. We also studied the potential mediating effect of 91 circulating inflammatory cytokines using a two-step MR method. Additionally, sensitivity analyses were conducted using MR-Egger intercept test and Cochran Q test to ensure the robustness of the outcomes. The results of forward MR analysis showed that anti-Epstein-Barr virus (anti-EBV) IgG seropositivity [OR = 0.941; 95% CI, 0.893-0.992; P = .023] and human herpes virus (HHV) 6 IE1A antibody levels [OR = 0.894; 95% CI, 0.816-0.981; P = .017] significantly reduced the risk of AP. The results of the reverse MR analysis revealed a negative correlation between AP and anti-EBV IgG seropositivity [OR = 0.775; 95% CI, 0.605-0.992; P = .043]. Furthermore, none of the 91 circulating inflammatory cytokines could mediate the causal relationship between HHV-6 IE1A antibody levels and the risk of AP. The results of sensitivity analysis confirmed the robustness of these causalities. The current study suggests that HHV-6 IE1A antibody levels are a protective factor against AP, and there is a bidirectional causality between AP and anti-EBV IgG seropositivity. In addition, the mediation analysis results showed that the 91 circulating inflammatory cytokines could not serve as mediators between the 46 antibody-mediated immune responses and AP.

Humans↗

PubMed2025

Immunosuppressant use may be a potential mediator in the progression of systemic lupus erythematosus to osteomyelitis: A bidirectional Mendelian randomization study.

The prevalence of osteomyelitis (OM) is elevated in patients with systemic lupus erythematosus (SLE), but the causal direction and proportion of immunosuppressant (IS) use in this relationship is unclear. Therefore, this study used a bidirectional Mendelian randomization (MR) study to investigate the causal relationship between SLE and OM and to quantify the role of IS use as a potential mediator. Genome-wide association study summary-level data were used to obtain genetic instrumental variables for SLE (5201 cases and 9066 controls), OM (1881 cases and 391,037 controls), and IS (3954 cases and 268,648 controls) genetic instrumental variables with no overlap between their participant populations. Causal and total effects of SLE and OM were analyzed using bidirectional MR. Subsequent "2-step" MR was used to assess the direct effect between the 2 and the indirect effect of IS. Inverse variance weighting was used as the primary method of MR, while a series of sensitivity analyses were performed to assess the reliability of the results. Forward MR of inverse variance weighting results demonstrated a positive causal association between SLE and OM (P = .003, odds ratio [OR] = 1.062, 95% confidence interval [Cl]-OR: 1.019-1.107). The reverse MR results indicated no causal effect of OM on SLE was found (P = .503, OR = 0.914, 95% Cl-OR: 0.703-1.188). The direct effect of SLE acting on OM in our study was found to be 19.36% by 2-step analysis, and the indirect effect of OM through IS was found to be 68.11% (proportion mediated: 68.11%; 95% CI = 0.2277331-1.134507). There was no heterogeneity in all MR analyses of causality, except for the MR analysis of SLE causally related to IS. Sensitivity analysis found no evidence of horizontal pleiotropy. The present study found an increased relative risk of OM in SLE. Mediation analysis suggested a potential substantial mediating role for IS; however, this estimate was highly imprecise and requires further validation. In clinical practice, clinicians should remain aware of the potential for IS therapy to influence infection risk, including OM, in SLE patients.

Humans↗

PubMed2025

Association between gynecological cancers and female infertility: insights from bidirectional Mendelian randomization analysis.

PURPOSE: In recent years, research interest in the potential link between female infertility (FI) and gynecological cancer (GC), including ovarian cancer (OC), endometrial cancer (EC), cervical cancer (CC), and breast cancer (BC), has grown, yet findings remain inconclusive. This study aims to explore the causal relationship between FI and GC using bidirectional two-sample Mendelian randomization (MR) analyses, thereby informing future strategies for FI and GC prevention. METHODS: We utilized SNPs identified from genome-wide association studies (GWAS) on FI and GC. The inverse variance weighted (IVW) method served as the primary approach to assess the causal association between FI and GC. Additionally, five other MR methods-Weighted median, Weighted mode, MR-Egger, Simple mode, and Robust-Adjusted Profile Score-were employed to enhance result robustness and credibility. RESULTS: In the forward MR analysis, our IVW results indicated no significant association between FI and GC (FI-BC: OR = 0.95, 95% CI: 0.83-1.09, P = 0.47, P-FDR = 0.775; FI-OC: OR = 1.01, 95% CI: 0.84-1.24, P = 0.789, P-FDR = 0.896; FI-CC: OR = 0.80, 95% CI: 0.61-1.06, P = 0.118, P-FDR = 0.775; FI-EC: OR = 1.07, 95% CI: 0.88-1.30, P = 0.490, P-FDR = 0.775).In the reverse MR analysis, we found a marginal association between BC and FI. However, after adjusting for multiple testing using the FDR method, no significant causal relationship was found between BC and FI, suggesting a marginal association (OR = 1.054, 95% CI: 1.001-1.108, P = 0.043, P-FDR = 0.331). For other cancers, no significant causal relationships were observed between OC, CC and EC with FI(OC-FI: OR = 1.043, 95% CI: 0.999-1.087, P = 0.051, P-FDR = 0.331;CC-FI: OR = 0.992, 95% CI: 0.956-1.028, P = 0.654, P-FDR = 0.836; EC-FI: OR = 1.006, 95% CI: 0.956-1.055, P = 0.809, P-FDR = 0.885). CONCLUSIONS: Our study found no significant causal relationship between FI and GC. However, a potential marginal association between BC and FI was observed. These findings underscore the need for further research to confirm this association and emphasize the importance of reproductive protection for young breast cancer patients to preserve fertility.

Humans↗

PubMed1992

Risk factors for cancer.

It is no longer reasonable to divide cancers into those that are genetic in origin and those that are environmental in origin. With rare exception, carcinogenesis involves environmental factors that directly or indirectly exert a change in the cell's genome. Virtually all causes of cancer are multifactorial, sometimes involving an inherited predisposition to the carcinogenic effects of environmental factors, which include chemicals, ionizing radiation, and oncogenic virus. Carcinogenesis is a multistep process including induction, promotion, and progression. Initiation requires an irreversible change in the cellular genome, whereas promotion is commonly associated with prolonged and reversible exposure. Tumor progression results in genotypic and phenotypic changes associated with tumor growth, invasion, and metastasis. Most information on human cancer risk is based on epidemiologic studies involving both exposed and unexposed individuals. The quality of such studies depends on their ability to assess the strength of any association of exposure and disease and careful attention to any potential bias. Few cancers are inherited in a Mendelian fashion. Several preneoplastic conditions, however, are clearly inherited and several malignancies demonstrate weak familial patterns. Environmental factors may exert their effect on DNA in a random fashion, but certain consistent changes, including specific translocations of genetic information, are often found. Currently, there is great interest in the close proximity of certain oncogenes governing growth control to the consistent chromosomal changes observed. Such changes may represent a final common pathway of action for environmental carcinogens. Sufficient laboratory and epidemiologic evidence exists to establish a causal association of several chemical agents with cancer. The most important carcinogenic chemicals are associated with life-style factors, whereas agents related to other environmental, occupational, or medical exposure are numerically less important. Most chemical agents exert their carcinogenic effects as electrophilic reactants covalently binding to DNA. Certain agents such as asbestos are carcinogenic by virtue of their physical properties. Several short-term tests have been used to screen for chemical carcinogens. Whole-animal studies remain the standard for predicting carcinogen risk in humans, although major limitations in such studies exist. Ionizing radiation also exerts its carcinogenic effect through damage to cellular macromolecules including DNA. Excess cancer risk appears after a latent period of several years following exposure. Risk increases in approximately a linear fashion in proportion to the radiation energy, cumulative dose, and a variety of host biologic factors. The greatest source of average radiation exposure to the US population is from the uranium decay product radon.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1975

Non-mendelian segregation in hybrids between chinese hamster cells.

Mechanisms of segregation have been examined in hybrids between Chinese hamster cells, where chromosome loss in comparison to other systems is minimal. Hybrid cells were grown in HAT medium and subjected to back selection with bromodeoxyuridine (BUDR) or azaguanine (AZG). In AZG or BUDR at 30 mug/ml, segregation began with a random high frequency event that gave rise to cells capable of growth in both HAT and back selection medium, unlike the precursor hybrid or original parental cell types. BUDR-resistant segregants were propagated serially in the presence of BUDR, and were examined by clonal analysis for changes in plating properties during long term culture. Over a period of 300 days the HAT/BUDR plating ratio for sergregant cells declined continuously. A parallel decrease was observed in the rate of H3-thymidine incorporation, along with a drop in thymidine kinase activity. These shifts took place only in the presence of BUDR, and could be reversed by altered selection in HAT medium. Clonal studies showed that the evolution of segregant properties occurred in most if not all cells of the population, and did not arise from variation and selection of minority cell types. These properties of the segregating system are not consistent with models based on gene mutation, chromosome rearrangements, or chromosome loss. The evolution of segregants resembles more closely a sorting-out progress, taking place by intracellular selection over many generations. The segregating units may conceivably be cytoplasmic determinants linked functionally to nuclear genes, and which serve to modulate the events of phenotypic expression. Several lines of evidence which bear on this concept are discussed.

Azaguanine↗