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Bidirectional association between abnormal cardiac conditions and epilepsy: A two-sample Mendelian randomization study.

BACKGROUND: Observational studies have consistently indicated a significant correlation between abnormal cardiac conditions and epilepsy. However, the association and direction of this relationship remain a subject of debate. This study employs a two-sample bidirectional Mendelian randomization (MR) approach to investigate the association between abnormal cardiac conditions and epilepsy. METHODS: Instrumental variables, represented by single nucleotide polymorphisms (SNPs) associated with epilepsy and various abnormal cardiac conditions, were derived from large-scale genome-wide association studies databases, including FinnGen and UK Biobank. Bidirectional MR analysis was conducted to estimate the association between epilepsy and abnormal cardiac conditions. Sensitivity analyses were performed using MR-Egger, weighted median, Inverse Variance Weighted, and MR pleiotropy residual sum and outlier methods. RESULTS: The forward MR analysis suggested a potential positive effect of atrial fibrillation and flutter (AF) and valvular heart diseases (VHD) on the risk of epilepsy. Conversely, the reverse MR analysis indicated that epilepsy might increase the susceptibility to AF, VHD, and heart failure. CONCLUSION: The findings support a bidirectional relationship between AF, VHD, and epilepsy, indicating that AF and VHD can elevate the risk of developing epilepsy, while epilepsy, in turn, can also increase the risk of developing AF and VHD. Furthermore, the study suggest that epilepsy may contribute to the development of heart failure. These results underscore the importance of screening for cardiac abnormalities in patients with epilepsy and vice versa, to better understand their clinical significance and potential as modifiable risk factors.

Humans↗

Association of C-reactive protein with blood pressure and hypertension: life course confounding and mendelian randomization tests of causality.

BACKGROUND: C-reactive protein (CRP) has repeatedly been associated with blood pressure and prevalent and incident hypertension, but whether a causal link exists is uncertain. METHODS AND RESULTS: We assessed the cross-sectional relations of CRP to systolic blood pressure, pulse pressure, and prevalent hypertension in a representative sample of >3500 British women aged 60 to 79 years. For both outcomes, substantial associations were observed. However, these associations were greatly attenuated by adjustment for a wide range of confounding factors acting over the life course. We further investigated causality using a Mendelian randomization approach by examining the association of the 1059G/C polymorphism in the human CRP gene with CRP and with blood pressure, pulse pressure, and hypertension. The polymorphism was associated with a robust difference in CRP, and the expectation would be for higher blood pressure and pulse pressure and greater prevalence of hypertension among those carrying the genetic variant associated with higher CRP levels. This was not observed, and the predicted causal effects of CRP on blood pressure, pulse pressure, and hypertension using instrumental variables methods were close to 0, although with wide CIs. CONCLUSIONS: CRP levels are associated with blood pressure, pulse pressure, and hypertension, but adjustment for life course confounding and a Mendelian randomization approach suggest the elevated CRP levels do not lead to elevated blood pressure.

Aged↗

Disentangling the association between chronic pain and sarcopenia-related traits: A bidirectional Mendelian randomization study.

ObjectiveThis study aimed to investigate the potential causal relationships between chronic pain and three key sarcopenia-related quantitative traits: (a) hand grip strength; (b) usual walking pace; and (c) appendicular lean mass, using bidirectional two-sample Mendelian randomization.MethodsWe conducted bidirectional two-sample Mendelian randomization using summary-level data from large-scale genome-wide association studies to assess the genetically predicted associations between chronic pain, including multisite chronic pain and chronic widespread musculoskeletal pain, and the aforementioned sarcopenia-related traits.ResultsMendelian randomization revealed that multisite chronic pain was significantly associated with an increased risk of low hand grip strength (odds ratio = 1.70; p&#x2009;<&#x2009;0.001) and decreased usual walking pace (odds ratio = 0.81; p&#x2009;<&#x2009;0.001); chronic widespread musculoskeletal pain was also significantly associated with decreased usual walking pace (odds ratio = 0.15; p&#x2009;<&#x2009;0.001). Additionally, higher left hand grip strength was significantly associated with a lower risk of multisite chronic pain (odds ratio = 0.90; p<&#x2009;0.001) and chronic widespread musculoskeletal pain (odds ratio = 0.99; p&#x2009;=&#x2009;0.002); higher right hand grip strength was significantly associated with a lower risk of multisite chronic pain (odds ratio = 0.91; p&#x2009;=&#x2009;0.002); and higher usual walking pace was significantly associated with a lower risk of multisite chronic pain (odds ratio = 0.49; p&#x2009;<&#x2009;0.001) and chronic widespread musculoskeletal pain (odds ratio = 0.92; p&#x2009;<&#x2009;0.001). No significant causal associations were detected for appendicular lean mass in either direction (all p&#x2009;>&#x2009;0.05).ConclusionThis study provides genetic evidence supporting potential causal links between chronic pain and key phenotypic components of sarcopenia.

Humans↗

Identification of Critical Genes for Recurrent Aphthous Ulcer by Transcriptome Data Analysis and Mendelian Randomization.

PURPOSE: Recurrent aphthous ulcer (RAU) is a common oral mucosal disorder with a poorly understood etiology, significantly affecting patients' quality of life. This study aims to investigate critical genes linked to RAU and explore their biological mechanisms using transcriptomic data and Mendelian randomization (MR) analysis. MATERIALS AND METHODS: RAU-related gene expression data from the GEO database (GSE37265) were analyzed to identify differentially expressed genes (DEGs). A two-sample MR approach was used to assess the causal impact of expression quantitative trait loci (eQTL) on RAU. Critical genes were identified by intersecting DEGs with significant MR findings. GO and KEGG pathway enrichment analyses were performed, along with GSEA and immune cell infiltration analysis, to investigate the functions and mechanisms of these genes in RAU. RESULTS: A total of 184 differentially expressed genes (DEGs) were identified, while 339 RAU-associated genes were screened through MR analysis. Cross-validation further identified 7 critical genes. Among these, CCR1, ERP27, HCK, MICB, and SLC2A3 showed protective associations with RAU risk, whereas CD177 and IFITM1 were positively associated with increased risk. Enrichment analysis revealed that these genes are involved in specific biological processes, including cell migration, immune response, and metabolic regulation, which are closely linked to RAU pathogenesis. CONCLUSION: This systematic study comprehensively investigates the critical causative genes underlying RAU, emphasizing the intricate relationships between immune regulation and metabolic disturbances in its pathology. These findings lay a solid foundation for the development of novel biomarkers and may inform future research on targeted therapeutic strategies for RAU.

Stomatitis, Aphthous↗

Exploring Potential Causality and Molecular Mechanisms between Heart Failure and Renal Failure: Insights from Mendelian Randomization Studies, the MIMIC-IV Database and the Gene Expression Omnibus Database.

UNLABELLED: Introduction: Heart failure (HF) and renal failure (RF) frequently coexist as cardiorenal syndrome, but their underlying causal mechanisms remain poorly defined. METHODS: This study applied Mendelian randomization (MR) using genome-wide association study (GWAS) datasets to investigate the causal effect of HF on RF. The inverse variance weighted method assessed causality, and summary-data-based MR (SMR) was used to identify therapeutic targets. Additional analyses included 211 gut microbiota traits and 1,400 serum metabolites. Validation was performed using the MIMIC-IV database. Transcriptomic data were analyzed to identify differentially expressed genes (DEGs) and key transcription factors (TFs). RESULTS: This study found that HF significantly increases the risk of RF (OR = 1.54, 95% CI: 1.07-2.23, p = 0.020). SMR analysis identified SURF1 and MAP3K11 as potential therapeutic targets for HF and RF. One gut microbiota genus and one serum metabolite showed causal associations with both diseases. MIMIC-IV data supported the HF-RF association (OR = 2.94, 95% CI: 2.81-3.07, p < 0.001). A total of 11 overlapping DEGs were enriched in the MAPK cascade, with RELA identified as a key TF. CONCLUSION: This study provides genetic and molecular evidence supporting a causal role of HF in RF, highlighting microbial, metabolic, and immune mechanisms as potential therapeutic targets. .

Humans↗

Mitochondrial Function-Related Genes in Sleep Disorders: A Multi-Omics Mendelian Randomization Study.

Mitochondrial dysfunction is linked to sleep disorders in previous report, but the potential roles of specific genes remain unclear. This study aimed to dissect different subtype-specific genetic associations and their underlying mechanisms. A multi-omics Summary-data-based Mendelian Randomization (SMR) approach was performed to identify potential causal links between mitochondrial function-related genes and sleep disorders. We integrated GWAS data from FinnGen database (the discovery set), independent GWAS datasets (covering different sleep-disorder subtypes and used for validation), and cis-QTLs (including mQTLs, eQTLs, and pQTLs) to perform systematic exploration. Specially, we performed targeted validation of tissue-specific effects, leveraging gene expression data from disease-relevant brain regions within the GTEx database. Our SMR analysis identified mitochondrial function-related genes potentially modulating sleep disorders across biological layers, initially identifying 102 genes at the methylation level, 48 at the gene expression level, and 6 at the protein abundance level. Integrative analysis subsequently prioritized DCXR and ACADVL and revealed their distinct, subtype-specific associations. DCXR exhibited a protective role in sleep apnea while ACADVL showed a paradoxical risk conferring role in daytime sleepiness. In addition, the analysis identified an epigenetic regulatory mechanism for DCXR in which its expression and protein levels are modulated by DNA methylation. Finally, validation in brain-hypothalamus tissue confirmed DCXR as a significant potential protective factor (OR&#x2009;=&#x2009;0.929, 95% CI: 0.887-0.973, P_HEIDI&#x2009;=&#x2009;0.999, FDR&#x2009;=&#x2009;0.2449). Our findings implicate key mitochondrial genes, particularly DCXR and ACADVL, in the pathophysiology of specific sleep disorder subtypes, highlighting potential avenues for precision medicine. Clinical trial number: Not applicable.

Humans↗

Association between Branched-Chain amino acids and Epilepsy: A Mendelian randomized study.

BACKGROUND: Branched-chain amino acids (BCAAs) have been affected epilepsy, yet conclusions remain inconclusive, lacking causal evidence regarding whether BCAAs affect epilepsy. Systematic exploration of the causal relationship between BCAAs and epilepsy could hand out new ideas for the treatment of epilepsy. METHODS: Utilizing bidirectional Mendelian randomization (MR) study, we investigated the causal relationship between BCAA levels and epilepsy. BCAA levels from genome-wide association studies (GWAS), including total BCAAs, leucine levels, isoleucine levels, and valine levels, were employed. Causal relationships were explored applying the method of inverse variance-weighted (IVW) and MR-Egger, followed by sensitivity analyses of the results to evaluate heterogeneity and pleiotropy. RESULTS: Through strict genetic variant selection, we find some related SNPs, total BCAA levels (9), leucine levels (11), isoleucine levels (7), and valine levels (6) as instrumental variables for our MR analysis. Following IVW and sensitivity analysis, total BCAAs levels (OR&#xa0;=&#xa0;1.14, 95&#xa0;% CI&#xa0;=&#xa0;1.019&#xa0;&#x223c;&#xa0;1.285, P&#xa0;=&#xa0;0.022) and leucine levels (OR&#xa0;=&#xa0;1.15, 95&#xa0;% CI&#xa0;=&#xa0;1.018&#xa0;&#x223c;&#xa0;1.304, P&#xa0;=&#xa0;0.025) had significant correlation with epilepsy. CONCLUSIONS: There exists a causal relationship between the levels of total BCAAs and leucine with epilepsy, offering the new ideas into epilepsy potential mechanisms, holding significant implications for its prevention and treatment.

Humans↗

Positive association between apolipoprotein B and colorectal cancer risk: Findings from a 14-year follow-up cohort study and Mendelian randomization analyses.

BACKGROUND: The effects of lipid traits on colorectal cancer (CRC) risk and the extent to which obesity may modify these effects remain unclear. OBJECTIVE: To examine the associations between lipid traits and CRC risk using an observational study and Mendelian randomization (MR) analyses, and the role of weight status in the potential associations. METHODS: In the Guangzhou Biobank Cohort Study (GBCS), lipid profiles were measured during 2003-2008, and CRC events were identified through record linkage with the cancer registry. MR analyses assessed the causal effects of lipid traits on CRC using a genome-wide association study meta-analysis of 185,616 Europeans. RESULTS: Among 28,576 GBCS participants followed until 2020, 599 CRC events occurred. Participants in the highest quartile of apolipoprotein B (apoB) had a higher CRC risk (hazard ratio [HR] 1.43, 95% CI&#xa0;1.02-2.01). This association remained in those with overweight/obesity (HR 2.21, 95% CI 1.28-3.83). MR analyses supported a detrimental effect of apoB on CRC (odds ratio 1.12 per 1 SD, 95% CI 1.02-1.22). MR analyses also showed positive associations for total cholesterol and the apoB/apolipoprotein A-I ratio, which were not significant in the observational study. CONCLUSION: Higher apoB levels were associated with an increased CRC risk in both observational and MR analyses, suggesting a potential role of apoB in CRC prevention, especially among participants with overweight/obesity. However, the limitations of single-time lipid measurements and the use of different ancestries across study designs indicate the need for further research to confirm the robustness and generalizability of the findings.

Humans↗

Severe traumatic brain injury and risk for osteoporosis: a Mendelian randomization study.

BACKGROUND: The influence of nervous system activity on bone remodeling has been widely reported. Patients with traumatic brain injury (TBI) exhibit a high incidence of osteoporosis (OP). Nevertheless, the relationship between severe TBI (sTBI) and OP remains unclear. We performed Mendelian randomization (MR) analysis to assess the potential causal relationship between sTBI and OP. METHODS: Data on exposure and outcomes were acquired from genome-wide association studies (GWAS). Data on OP was obtained from UK Biobank (5,266 cases of OP and 331,893 controls). Data on sTBI was obtained from FinnGen Consortium (6,687 cases and 370,590 controls). Single nucleotide polymorphisms (SNPs) that underwent strict screening were regarded as instrumental variables. We used the inverse variance weighted (IVW), constrained maximum likelihood and model averaging (CML-MA), MR-Egger, and weighted median methods for causal effect estimation. To test the reliability of the results, sensitivity analysis was performed using Cochran's Q, leave-one-out, MR-Egger intercept, and MR Pleiotropy RESidual Sum and Outlier (MR-PRESSO) tests. RESULTS: The IVW analysis indicates that sTBI and OP have a suggestive association (odds ratio [OR]&#x2009;=&#x2009;1.004, 95% confidence interval [CI]&#x2009;=&#x2009;1.001,1.007; p&#x2009;=&#x2009;0.002), and no heterogeneity (Q&#x2009;=&#x2009;11.536, p&#x2009;=&#x2009;0.241) or directional pleiotropy was observed (egger_intercept&#x2009;=&#x2009;7.368&#x2009;&#xd7;&#x2009;10-&#x2009;5, p&#x2009;=&#x2009;0.870). The robustness of the results was validated using a leave-one-out sensitivity test. CONCLUSION: According to the MR analysis, sTBI and OP are likely suggestively related. This finding contributes to the prevention of OP in patients with sTBI and provides genetic evidence supporting the theory that the nervous system regulates bone remodeling.

Humans↗

Multiple metabolic factors and kidney dysfunction: Causal evidence and translational insights from a mendelian randomization study.

Chronic kidney disease is a major global public health burden. This study investigated the causal effects of systolic blood pressure (SBP), apolipoprotein B (ApoB), and serum urate on renal function and albuminuria, and explored potential mechanistic implications. Two-sample Mendelian randomization (MR) analyses were conducted using large-scale genome-wide association study summary statistics from European populations. Univariable MR estimated total causal effects on estimated glomerular filtration rate (eGFR) and albuminuria. Multivariable MR assessed independent effects of correlated exposures, and 2-step MR evaluated albuminuria as a mediator. Cis-MR analyses were performed to explore target-proximal genetic evidence for lipid-related drug targets. Genetically predicted SBP was causally associated with reduced eGFR, while ApoB was inversely associated with albuminuria risk. serum urate showed no significant causal effects. Multivariable and mediation analyses supported distinct roles of SBP and ApoB, with albuminuria partially mediating the SBP-eGFR association. Cis-MR analyses indicated heterogeneous renal effects of lipid-lowering targets. These findings provide genetic evidence linking SBP to renal dysfunction, suggest that albuminuria may partially mediate the association between SBP and renal function, and highlight the complex renal relevance of lipid-related pathways.

Mendelian Randomization Analysis↗

A Causal Effect of Serum 25(OH)D Level on Appendicular Muscle Mass: Evidence From NHANES Data and Mendelian Randomization Analyses.

BACKGROUND: Low serum vitamin D status was reported to be associated with reduced muscle mass; however, it is inconclusive whether this relationship is causal. This study used data from the National Health and Nutrition Examination Survey (NHANES) and two-sample Mendelian randomization (MR) analyses to ascertain the causal relationship between serum 25-hydroxyvitamin D [25(OH)D] and appendicular muscle mass (AMM). METHODS: In the NHANES 2011-2018 dataset, 11&#x2009;242 participants (5588 males and 5654 females) aged 18-59&#x2009;years old were included, and multivariant linear regression was performed to assess the relationship between 25(OH)D and AMM measured by dual-energy X-ray absorptiometry. In two-sample MR analysis, 167 single nucleotide polymorphisms significantly associated with serum 25(OH)D at the genome-wide association level (p&#x2009;<&#x2009;5&#x2009;&#xd7;&#x2009;10-8) were applied as instrumental variables (IVs) to assess vitamin D effects on AMM in the UK Biobank (417&#x2009;580 Europeans) using univariable and multivariable MR (MVMR) models. RESULTS: In the NHANES dataset, serum 25(OH)D concentrations were positively associated with AMM (&#x3b2;&#x2009;=&#x2009;0.013, SE&#x2009;=&#x2009;0.001, p&#x2009;<&#x2009;0.001) in all participants, after adjustment for age, race, season of blood collection, education, income, body mass index and physical activity. In stratification analysis by sex, males (&#x3b2;&#x2009;=&#x2009;0.024, SE&#x2009;=&#x2009;0.002, p&#x2009;<&#x2009;0.001) showed more pronounced positive associations than females (&#x3b2;&#x2009;=&#x2009;0.003, SE&#x2009;=&#x2009;0.002, p&#x2009;=&#x2009;0.024). In univariable MR, genetically higher serum 25(OH)D levels were positively associated with AMM in all participants (&#x3b2;&#x2009;=&#x2009;0.049, SE&#x2009;=&#x2009;0.024, p&#x2009;=&#x2009;0.039) and males (&#x3b2;&#x2009;=&#x2009;0.057, SE&#x2009;=&#x2009;0.025, p&#x2009;=&#x2009;0.021), but only marginally significant in females (&#x3b2;&#x2009;=&#x2009;0.043, SE&#x2009;=&#x2009;0.025, p&#x2009;=&#x2009;0.090) based on IVW models was noticed. No significant pleiotropy effects were detected for the IVs in the two-sample MR investigations. In MVMR analysis, a positive causal effect of 25(OH)D on AMM was observed in the total population (&#x3b2;&#x2009;=&#x2009;0.116, SE&#x2009;=&#x2009;0.051, p&#x2009;=&#x2009;0.022), males (&#x3b2;&#x2009;=&#x2009;0.111, SE&#x2009;=&#x2009;0.053, p&#x2009;=&#x2009;0.036) and females (&#x3b2;&#x2009;=&#x2009;0.124, SE&#x2009;=&#x2009;0.054, p&#x2009;=&#x2009;0.021). CONCLUSIONS: Our results suggested a positive causal effect of serum 25(OH)D concentration on AMM; however, more researches are warranted to unveil the underlying biological mechanisms and evaluate the effects of vitamin D intervention on AMM.

Humans↗

Mendelian randomization analysis reveals higher whole body water mass may increase risk of bacterial infections.

BACKGROUND AND PURPOSE: The association of water loading with several infections remains unclear. Observational studies are hard to investigate definitively due to potential confounders. In this study, we employed Mendelian randomization (MR) analysis to assess the association between genetically predicted whole body water mass (BWM) and several infections. METHODS: BWM levels were predicted among 331,315 Europeans in UK Biobank using 418 SNPs associated with BWM. For outcomes, we used genome-wide association data from the UK Biobank and FinnGen consortium, including sepsis, pneumonia, intestinal infections, urinary tract infections (UTIs) and skin and soft tissue infections (SSTIs). Inverse-variance weighted MR analyses as well as a series of sensitivity analyses were conducted. RESULTS: Genetic prediction of BWM is associated with an increased risk of sepsis (OR 1.34; 95% CI 1.19 to 1.51; P&#x2009;=&#x2009;1.57&#x2009;&#xd7;&#x2009;10-&#x2009;6), pneumonia (OR: 1.17; 95% CI 1.08 to 1.29; P&#x2009;=&#x2009;3.53&#x2009;&#xd7;&#x2009;10-&#x2009;4), UTIs (OR: 1.26; 95% CI 1.16 to 1.37; P&#x2009;=&#x2009;6.29&#x2009;&#xd7;&#x2009;10-&#x2009;8), and SSTIs (OR: 1.57; 95% CI 1.25 to 1.96; P&#x2009;=&#x2009;7.35&#x2009;&#xd7;&#x2009;10-&#x2009;5). In the sepsis and pneumonia subgroup analyses, the relationship between BWM and infection was observed in bacterial but not in viral infections. Suggestive evidence suggests that BWM has an effect on viral intestinal infections (OR: 0.86; 95% CI 0.75 to 0.99; P&#x2009;=&#x2009;0.03). There is limited evidence of an association between BWM levels and bacteria intestinal infections, and genitourinary tract infection (GUI) in pregnancy. In addition, MR analyses supported the risk of BWM for several edematous diseases. However, multivariable MR analysis shows that the associations of BWM with sepsis, pneumonia, UTIs and SSTIs remains unaffected when accounting for these traits. CONCLUSIONS: In this study, the causal relationship between BWM and infectious diseases was systematically investigated. Further prospective studies are necessary to validate these findings.

Humans↗

Causal association between non-steroidal anti-inflammatory drugs use and the risk of benign prostatic hyperplasia: a univariable and multivariable Mendelian randomization study.

BACKGROUND: The results of earlier observational research on the relationships between the usage of non-steroidal anti-inflammatory medicines (NSAIDs) and the risk of benign prostatic hyperplasia (BPH) have been inconsistent. METHODS: To assess these associations, we performed both univariable and multivariable Mendelian randomization (MR) studies. Instrumental variables (IVs) associated with exposures at the significance level (p&#x2009;<&#x2009;5&#x2009;&#xd7;&#x2009;10-6) were selected from a comprehensive meta-analysis conducted by the United Kingdom Biobank (UKB). Summary data for BPH were obtained from the FinnGen consortium, which comprised 30,066 cases and 119,297 controls. Sensitivity analyses were performed to evaluate heterogeneity and pleiotropy. RESULTS: We found evidence by univariable MR (UVMR) that genetically predicted NSAIDs use increased the risk of BPH (odds ratio [OR] per unit increase in log odds NSAIDs use: 1.164, 95% confidence interval [CI]: 1.041-1.302, p&#x2009;=&#x2009;0.008). After controlling for inflammation in multivariable MR (MVMR), the link persisted (OR: 1.165, 95% CI: 1.049-1.293, p&#x2009;=&#x2009;0.004). There were no indications of potential heterogeneity and pleiotropy in UVMR and MVMR analyses. CONCLUSION: The results of the MR estimates suggest that genetically predicted NSAIDs use may elevate the risk of BPH. This outcome prompts the imperative for deeper exploration into potential underlying mechanisms.

Humans↗

Biological Mechanisms Underlying the Cardiovascular Effects of Branched-Chain Amino Acids: A Proteome-Wide Mendelian Randomization Study.

BACKGROUND: Ischemic heart disease (IHD) is the leading cause of morbidity and mortality. Branched-chain amino acids (BCAAs) are associated with higher IHD risk, but the underlying biological pathways remain unclear. OBJECTIVES: This study aims to explore these pathways using 2-step proteome-wide Mendelian randomization. METHODS: We examined the associations between genetic proxies for BCAAs and 2922 proteins in the United Kingdom Biobank Pharma Proteomics Project, supplemented by a meta-analysis with data from deCODE to identify proteins associated with BCAAs. Next, we tested their effects on IHD risk using Coronary Artery Disease Genome-wide Replication and Meta-analysis plus Coronary Artery Disease Genetics Consortium (122,733 cases and 424,528 controls) and replicated in FinnGen (31,640 cases and 187,152 controls). We conducted sensitivity analyses using genetic instruments from deCODE. Proteins associated with IHD risk and, in a consistent direction, with genetically predicted BCAAs were considered potential mediators. RESULTS: Genetic proxies for BCAAs were associated with 40 proteins. Among these, 6 proteins showed consistent evidence of mediation, including complement C1s subcomponent, coagulation factor II, granulin, proprotein convertase subtilisin/kexin type 9, sex hormone-binding globulin, and V-set and transmembrane domain-containing protein 2-like. These proteins are involved in inflammation, coagulation, lipid metabolism, and cellular stress response. All associations were robust across different analytical methods and replicated in independent datasets. Mediation analysis showed that these proteins accounted for 6.5% to 32.1% of the association between BCAAs and IHD risk. CONCLUSIONS: This study identified 6 proteins that potentially link BCAAs to IHD, implicating pathways related to inflammation, coagulation, lipid metabolism, and cellular stress responses. To our knowledge, these findings provide novel mechanistic insights into the BCAA-IHD relationship and highlight potential protein targets for future prevention and intervention strategies.

Amino Acids, Branched-Chain↗

Causal associations between inflammatory bowel disease and sepsis: a two-sample Mendelian randomization study.

BACKGROUND: Recent observational studies have revealed an inconclusive correlation between inflammatory bowel disease (IBD) and sepsis, accompanied by an uncertain understanding of the causal relationship between the two. To investigate the causality between IBD and sepsis, we employed a two-sample Mendelian randomization (MR) approach. METHODS: A genome-wide significant threshold (P&#x2009;<&#x2009;5&#x2009;&#xd7;&#x2009;10-8) was achieved in order to identify single nucleotide polymorphisms (SNPs) as instrumental variables (IVs) for two types of IBD, such as Crohn's disease (CD) and ulcerative colitis (UC). Subsequently, the selected SNPs were assessed in relation to three categories of sepsis, namely sepsis, sepsis (critical care), and sepsis (28-day death in critical care). An inverse-variance weighted (IVW) estimation of MR was conducted, followed by sensitivity analysis on multiple dimensions. RESULTS: There was a significant association between genetic liability to CD (IVW: OR, 1.246; 95% CI, 1.090-1.423; P&#x2009;=&#x2009;0.0012) with sepsis (28-day death in critical care), but not with sepsis (critical care) and sepsis. Whereas UC showed slightly, yet statistically insignificant, higher risk for sepsis (IVW: OR, 1.031; 95% CI, 0.988-1.064; P&#x2009;=&#x2009;0.064). CONCLUSION: Our study offers genetic evidence that supports a substantial causal relationship between CD and sepsis (28-day death in critical care). To enhance the specificity and objectivity of future research findings, it is recommended to specify the types of IBD and the severity of sepsis. Furthermore, the genetic risk loci related may become potential drug development targets.

Humans↗

Entertainment activities and the risk of multiple sclerosis: A Mendelian randomization analysis.

Modifying environmental and lifestyle factors may have the potential to prevent and ameliorate multiple sclerosis. Further elucidating the etiology of multiple sclerosis and proposing actionable prevention measures are of significant importance, but establishing causality in epidemiological data can be challenging. This study employed a two-sample Mendelian randomization analysis to evaluate the causal effect of entertainment activity factors on the risk of multiple sclerosis. Publicly accessible summary statistics derived from genome-wide association studies were utilized to assess 14 modifiable forms of entertainment activities. The inverse variance weighted random effects method was used as the primary analytical approach to estimate causal effects. Additionally, MR-Egger, weighted median, and weighted mode methods were applied to assess robustness. Systematic sensitivity analyses and heterogeneity tests were conducted to verify the reliability of our findings. We found that spending time outdoors in the summer may prevent the development of multiple sclerosis (odds ratio = 0.995; 95% confidence interval 0.991-0.999; P&#x2005;=&#x2005;.010). In contrast, the other entertainment activities studied showed no significant causal relationship with multiple sclerosis. Our results suggest that spending time outdoors in the summer may protect against the development of multiple sclerosis, providing implications for preventive measures against the disease.

Humans↗

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&#x2005;=&#x2005;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-&#x3b2;) were significantly associated with increased OM risk (odds ratio [OR]&#x2005;=&#x2005;1.132; 95% confidence interval [CI]: 1.052-1.217; false discovery rate [FDR]&#x2005;=&#x2005;0.027). Conversely, decreased levels of osteoprotegerin (OR&#x2005;=&#x2005;0.772; 95% CI: 0.671-0.889; FDR&#x2005;=&#x2005;0.015) and adenosine deaminase (OR&#x2005;=&#x2005;0.811; 95% CI: 0.736-0.894; FDR&#x2005;<&#x2005;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&#x2005;<&#x2005;0.05). Colocalization analysis provided strong evidence for a shared causal variant between TNF-&#x3b2; and OM (posterior probability for hypothesis 4&#x2005;=&#x2005;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-&#x3b2;, 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↗

Migraine is not a risk factor for glaucoma: Evidence from a bidirectional Mendelian randomization study.

Numerous compelling observational studies have indicated that migraine is a risk factor for the development of glaucoma. Nevertheless, some studies have observed entirely opposite results. The objective of our research is to evaluate the potential relationship between migraine and glaucoma by employing a bidirectional Mendelian Randomization (MR) approach. This method enables us to rigorously assess the causal links between these 2 conditions, thereby addressing the discrepancies in existing literature. Independent genetic variants associated with glaucoma and migraine at the genome-wide significance level were selected as instrumental variables. All summary data were obtained from the genome-wide association study database. The primary method employed in the bidirectional MR analysis was the inverse variance weighted method, while sensitivity analyses utilized the leave-one-out method, MR-Egger method, and MR-Pleiotropy RESidual Sum and Outlier&#x200c; method. When migraine and its subtypes (specifically migraine with aura and migraine without aura) were evaluated as exposure factors, we found no evidence of a causal relationship with glaucoma and its subtypes (namely angle-closure glaucoma and open-angle glaucoma). Subsequently, in the reverse MR analysis, when glaucoma and its subtypes (angle-closure glaucoma and open-angle glaucoma) were assessed as exposure factors, there was no substantial evidence to support a causal relationship with migraine or its subtypes (migraine with aura and migraine without aura). Furthermore, sensitivity analyses also reinforced the robustness of our bidirectional MR findings. Our bidirectional MR analysis mitigates the biases associated with traditional observational studies, highlighting that there is no direct causal relationship between migraine and the risk of glaucoma.

Humans↗