Primary Method Of Analysis Research Articles

Abstract 4138335: A drug target Mendelian randomization study of triglyceride lowering therapies for aortic stenosis

Introduction: Large observational and Mendelian randomization (MR) studies have demonstrated a strong association between elevated triglycerides (TG) and risk of aortic stenosis (AS). However, at present there remains no evidence for the use of lipid-lowering therapies to prevent or treat AS. To address this gap, we used a drug target MR approach to investigate whether emerging TG lowering therapies may reduce the risk of AS. Methods: We collected summary statistics for TG levels and AS from genome-wide association studies including 1,253,277 and 653,867 European participants, respectively. We first performed conventional MR techniques to investigate a causal relationship between TG levels and AS risk. Next, we identified genetic proxies for the TG-lowering therapies fenofibrate, volanesorsen and evinacumab as single nucleotide polymorphisms (SNPs) within 200kb of the target genes ( PPARA, APOC3 and ANGPTL3 , respectively) which were also significantly associated with TG at p<5x10 -8 and clumped using threshold r 2 <0.1. Inverse-variance weighted (IVW) was the primary analysis method. We then performed sensitivity analyses including weighted-median and MR-Egger. Additional outlier-exclusion analyses were performed using MR-PRESSO and Cook’s distance. Finally, we completed sensitivity analyses using a more stringent clumping threshold of r 2 <0.01. Results: Consistent with previous findings we found genetically predicted TG levels were significantly associated with increased risk of AS (IVW: OR 1.28 per standard deviation increase in genetically predicted log TG level, 95% CI 1.18-1.39, p<0.0001). We further found that genetically proxied volanesorsen was significantly associated with reduced risk of AS (OR 0.54, 95% CI 0.39-0.75, p=0.0002), which was robust in all sensitivity analyses. We did not find evidence of a causal relationship between genetically proxied fenofibrate (IVW: OR 0.50, 95% CI 0.09-2.76, p=0.43) or evinacumab (IVW: OR 1.03, 95% CI 0.73-1.44, p=0.88) and risk of AS. Conclusions: Genetically proxied APOC3 inhibition, but not PPARA or ANGPTL3 , was robustly associated with reduced risk of AS. This suggests that APOC3 inhibition may be a therapeutic opportunity for AS management and warrants further research in the clinical trial setting.

A causal association between chemokines and the risk of lung cancer: a univariate and multivariate mendelian randomization study

BackgroundObservational studies and experimental evidence have shown that chemokines play important roles in lung cancer development, progression, and treatment. However, few studies have examined the causal association between them.MethodsSummary data of chemokines and lung cancer were obtained from genome-wide association studies. Mendelian randomization (MR) analyses were performed by five methods, Inverse variance weighted (IVW), Weighted median estimation, MR-Egger, Simple mode and Weighted, with IVW as the primary analysis method. Sensitivity analysis was used to assess the reliability of the MR results. Multivariate Mendelian randomization studies were used to infer whether causality was influenced by potential mediators. The expression levels of CCL21 were analyzed by quantitative real-time PCR.ResultsWe found that CCL21 was negatively associated with lung adenocarcinoma risk. CCL25 was positively associated with lung squamous cell carcinoma risk. CCL5 was negatively associated with small cell lung cancer risk. CCL21, CCL24, CCL27, and CCL28 was positively associated with small cell lung cancer risk. After multivariate Mendelian randomization adjustment for smoking behavior, it was found that the effect of CCL25 on lung squamous cell cancer disappeared, and the effect of CCL21 on small cell lung cancer was quite opposite to the univariate. The receiver operating characteristic curve indicated that chemokines had high accuracy in the diagnosis of lung cancer. CCL21 expression levels showed large differences in lung adenocarcinoma cells.ConclusionThese results highlighted the causal effects of chemokines on lung cancer and suggested a mediating role of smoking behavior in the association between chemokines and lung cancer.

Genetic determinants of cerebrospinal fluid metabolites and risk of Guillain-Barré syndrome: A bidirectional two-sample Mendelian randomization study

This study aims to investigate the potential causal relationship between cerebrospinal fluid (CSF) metabolites and Guillain-Barré syndrome (GBS) using a bidirectional two-sample Mendelian randomization (MR) approach. Publicly available summary data from genome-wide association studies (GWAS) were utilized for comprehensive analysis. The CSF metabolite GWAS summary data were extracted from a GWAS conducted by Panyard et al encompassing 338 CSF metabolites in European participants (n = 291). GWAS summary statistics for GBS were obtained from the FinnGen consortium (n = 215,931) comprising European populations. The primary method for MR analysis was the inverse variance weighted method. Various sensitivity analyses were conducted to assess the heterogeneity and pleiotropy of the findings. In the forward MR analysis, we identified a causal relationship between 15 CSF metabolites, including ribitol levels (odds ratio = 3.833, 95% confidence interval: 1.949–7.540, P = 9.87E−05), and the risk of developing GBS. In the reverse MR analysis, we found a causal relationship between GBS and 21 CSF metabolites, including gamma-glutamylphenylalanine levels (odds ratio = 0.934, 95% confidence interval: 0.904–0.966, P = 7.10E−05). No evidence of heterogeneity or horizontal pleiotropy was found in the MR analysis. Our findings suggest that the identified CSF metabolites and metabolic pathways can serve as valuable biomarkers for clinical screening and prevention of GBS. They may also be considered as candidate molecules for future research into the underlying mechanisms and for selecting drug targets.

Exploring causal associations between dietary intake and liver diseases: A bidirectional Mendelian randomization study

Previous evidence suggests that dietary intake can affect liver diseases; However, the causal relationship between dietary intake and liver diseases remains unclear. To investigate this, we conducted a bidirectional Mendelian randomization (MR) analysis to comprehensively assess the potential causal relationship between dietary intake and liver diseases. Two-sample bidirectional MR was performed based on genome-wide association studies summary data from the UK Biobank and FinnGen database. The primary analysis method for evaluating causal relationships was inverse-variance weighted. Supplementary analyses included MR-Egger and weighted median methods. Subsequently, sensitivity analyses were performed using Cochran Q test, MR-Egger intercept test, MR-PRESSO, RadialMR, and leave-one-out analysis to assess heterogeneity and horizontal pleiotropy. MR evidence indicated that genetically predicted poultry intake (adjusted odds ratio [OR] = 0.04, 95% confidence interval [CI] = 0.00–0.43, P = .007) and salad/raw vegetable intake (adjusted OR = 0.18, 95% CI = 0.04–0.83, P = .028) were directly associated with a reduced risk of cirrhosis. Conversely, there is no causal association between dietary intake and nonalcoholic fatty liver disease, alcoholic liver disease, or hepatocellular carcinoma. This study provides evidence supporting the impact of dietary intake on liver disease. Increased intake of poultry and salad/raw vegetables is associated with a reduced risk of cirrhosis. These findings can inform preventive and therapeutic strategies for cirrhosis.

Collatz Conjecture

This paper presents an analysis of the number of zeros in the binary representation of natural numbers. The primary method of analysis involves the use of the concept of the fractional part of a number, which naturally emerges in the determination of binary representation. This idea is grounded in the fundamental property of the Riemann zeta function, constructed using the fractional part of a number. Understanding that the ratio between the fractional and integer parts of a number, analogous to the Riemann zeta function, reflects the profound laws of numbers becomes the key insight of this work. The findings suggest a new perspective on the interrelation between elementary properties of numbers and more complex mathematical concepts, potentially opening new directions in number theory and analysis.This analysis has allowed to understand that the Collatz sequence initially tends towards a balanced symmetric arrangement of zeros and ones, and then it collapses, realizing the scenario of the Collatz conjecture.

Analyzing the causal role of blood cells in aging: a Mendelian randomization study.

Blood cells are crucial components of the human body, closely linked to the aging process. This study aims to explore the causal relationship between 91 blood cell phenotypes and aging through Mendelian randomization (MR) analysis. Exposure data from genome-wide association studies (GWAS) was extracted from the GWAS of blood cell perturbation phenotypes in 2,600 European individuals. Initial analysis utilized GWAS data related to aging from the GWAS Catalog database GCST90014288, with inverse-variance weighting as the primary method for causal analysis. Sensitivity analyses included Cochran's Q test, MR-Egger intercept test, MR-PRESSO, and leave-one-out analysis. For significant associations, replication and meta-analysis were conducted using independent aging GWAS data from GCST90014300. Initial analysis revealed that environmental peroxide-impacted red blood cells and ciprofloxacin-impacted reticulocytes accelerated aging. Additionally, elevated neutrophil levels were found to accelerate aging, while LiCl-impacted neutrophils reduced aging risk. Replication and meta-analysis showed consistent results: ciprofloxacin-impacted reticulocytes and elevated neutrophil levels increased the risk of aging, while LiCl-impacted neutrophils reduced the risk. RBCs showed no significant impact on aging progression. Sensitivity analyses confirmed the robustness and reliability of these positive findings. Our study provides evidence of a causal relationship between three blood cell disturbance phenotypes and human aging.

The Causal Role of Thyroid Hormones in Bipolar Disorders: A Two-Sample Mendelian Randomization Study.

Bipolar disorder is a complex psychiatric condition with distinctions between clinical subtypes including Type 1 and 2 disorders. Several studies have proposed that thyroid hormones may be involved in the aetiology of bipolar disorders. This study employed a two-sample Mendelian randomization (MR) approach to investigate the causal relationships between six thyroid hormone metrics (TSH, FT4, FT3, TT3, FT3/FT4 and TT3/FT4) and bipolar disorder and Type 1 and 2 disorders, separately. Genome-wide association (GWAS) data from the ThyroidOmics Consortium (up to 271,040 individuals of European ancestry) were used for thyroid function metrics. Bipolar disorder GWAS data included 41,917 cases and 371,549 controls (25,060 Type 1 and 6,781 Type 2 cases). We applied inverse variance weighted (IVW) methods for primary MR analysis, with MR Egger, weighted median and weighted mode for sensitivity. Additional tests assessed horizontal pleiotropy and heterogeneity. Higher FT4 levels showed a protective causal effect against bipolar disorder (OR: 0.92, 95% CI: 0.86-0.97, p = 4.58 × 10-3) and a suggestive effect on Type 1 disorders (OR: 0.92, 95% CI: 0.86-0.99, p = 3.21 × 10-2). Elevated FT3 (OR: 1.18, 95% CI: 1.03-1.35, p = 1.55 × 10-2) and FT3/FT4 ratio (OR: 1.97, 95% CI: 1.02-3.82, p = 4.46 × 10-2) had suggestive harmful effects on Type 1 disorders. Sensitivity analyses showed consistent effects, with no significant horizontal pleiotropy or heterogeneity. These findings highlight the protective role of FT4 and the potentially harmful effect of elevated FT3 in Type 1 bipolar disorder, highlighting the need for further research on thyroid hormone levels as a potential treatment strategy for Type 1 bipolar disorder.

Preliminary Study of Air Pollution and Adverse Pregnancy Outcomes: A Mendelian Randomization Study

The chief aim of this research is to investigate the causality of air pollutants and adverse pregnancy outcomes. Two-sample Mendelian randomization was conducted, employing genetic variants connected with air pollution as instrumental variables. Sixteen adverse pregnancy outcomes were extracted as the main outcome measures from the genome-wide association study (GWAS). The inverse-variance weighted (IVW) method was conducted as the primary analysis method. This study found that there were causal association between NO2 and pre-eclampsia (weighted median: OR = 1.30, 95% CI = [1.03–1.64], p = 0.029) and between PM2.5 and placental abruption (IVW: OR = 10.94, 95% CI = [1.28–93.45], p = 0.029). There were potential causal relationships between NO2 and gestational hypertension (IVW: OR = 1.14, 95% CI = [0.99–1.30], p = 0.060); NO2 and placental abruption (IVW: OR = 1.97, 95% CI = [0.90–4.28], p = 0.089); NOx and fetal growth restriction (IVW: OR = 0.06, 95% CI = [0.99–1.12], p = 0.089); PM2.5 and slow fetal growth and fetal malnutrition (MR–Egger: OR = 54,240.95, 95% CI = [2.08–1,411,757,729.46], p = 0.059); PM10 and hyperemesis gravidarum (MR–Egger: OR = 0.12, 95% CI = [0.02–0.97], p = 0.086); PM10 and preterm birth (weighted median: OR = 1.60, 95% CI = [0.95–2.70], p = 0.075); and PM10 and spontaneous abortion (weighted median: OR = 1.60, 95% CI = [0.95–2.70], p = 0.075). There was no pleiotropy, but there was some heterogeneity. In conclusion, air pollution has a causal effect on several adverse pregnancy outcomes.

Exploring the association between skin microbiota and inflammatory skin diseases: a two-sample Mendelian randomization analysis.

Dysbiosis in the skin microbiome is closely associated with various inflammatory skin diseases. However, current research on the causal relationship between the skin microbiome and inflammatory skin diseases lacks comprehensive and detailed investigation. We used a two-sample Mendelian randomization (MR) approach to explore associations between the skin microbiome and seven inflammatory skin diseases, including acne, atopic dermatitis, erysipelas, vitiligo, psoriasis, rosacea, and urticaria. The GWAS summary data for the skin microbiome was derived from 647 participants in two German population-based cohorts, and for the inflammatory skin diseases, they were sourced from the FinnGen consortium. Our primary MR analysis method was the inverse variance weighted (IVW) method, complemented by alternatives like MR-Egger regression, weighted median estimation, and constrained maximum likelihood. Sensitivity analyses, including Cochran's Q test, MR-Egger intercept test, and MR-PRESSO outlier detection, were conducted to validate and stabilize our findings. We identified significant causal relationships between the skin microbiome and seven inflammatory skin diseases: acne, atopic dermatitis, erysipelas, vitiligo, psoriasis, rosacea, and urticaria, with 7, 6, 9, 1, 7, 4, and 7 respective causal relationships for each disease. These relationships comprise 20 protective and 14 risk causal relationships. We applied the false discovery rate correction to these results. Sensitivity analysis revealed no significant pleiotropy or heterogeneity. Our study revealed both beneficial and detrimental causal relationships between diverse skin microbiota and inflammatory skin diseases. Additionally, the ecological niche of the skin microbiome was crucial to its functional impact. This research provided new insights into how skin microbiota impacted skin diseases and the development of therapeutic strategies.

A Mendelian randomization study of the association between serum uric acid and osteoporosis risk.

The relationship between serum uric acid (SUA) and osteoporosis (OP) has yielded conflicting results in observational studies. This Mendelian randomization (MR) study aims to elucidate the causal association between SUA and OP. A two-sample MR analysis was conducted using summary-level data from genome-wide association studies (GWAS). Two sets of polygenic instruments strongly associated (p < 5 × 10-8) with SUA were extracted from the CKDGen consortium and UK biobank. Polygenic instruments associated with OP (p < 5 × 10-8) were derived from FinnGen biobank and UK biobank. Inverse variance weighting (IVW) was employed as the primary analysis method. Additionally, we utilized MR-Egger, weighted median, the simple mode method, and the weighted mode as complementary analyses. Cochran's Q statistics were used to assess heterogeneity, with MR-Egger intercept testing and MR pleiotropy residual sum and outlier (MR-PRESSO) to examine horizontal pleiotropy. Sensitivity analysis was performed using the leave-one-out method. The IVW analysis conducted across four groups confirms no significant causal relationship between SUA concentration and OP: UKB-UKB (OR: 1.001, 95% CI: 0.999-1.003, p=0.464), CKD-UKB (OR: 1.001, 95% CI: 0.999-1.003, p=0.349), UKB-Fin (OR: 0.934, 95% CI: 0.747-1.168, p=0.549), CKD-Fin (OR: 1.041, 95%CI: 0.934-1.161, p=0.470). Furthermore, additional four MR analyses corroborated these findings. Upon excluding all outliers identified by the MR-PRESSO test, no significant directional pleiotropy was observed, except for some data heterogeneity noted in the UKB-UKB group (Q=50.65, P=0.002). Additionally, a leave-one-out analysis indicated that no single SNP exerted undue influence on the results. This MR analysis provides convincing genetic evidence that there is no causal association between SUA and OP, SUA is unlikely to increase or reduce the risk of OP.

The role of mitochondrial DNA copy number in autoimmune disease: a bidirectional two sample mendelian randomization study.

Mitochondrial DNA (mtDNA) plays an important role in autoimmune diseases (AD), yet the relationship between mitochondria and autoimmune disease is controversial. This study employed bidirectional Mendelian randomization (MR) to explore the causal relationship between mtDNA copy number and 13 ADs (including ankylosing spondylitis [AS], Crohn's disease [CD], juvenile rheumatoid arthritis [JRA], polymyalgia rheumatica [PMR], psoriasis [PSO], rheumatoid arthritis [RA], Sjogren's syndrome [SS], systemic lupus erythematosus [SLE], thyrotoxicosis, type 1 diabetes mellitus [T1DM], ulcerative colitis [UC], and vitiligo). A two-sample MR analysis was performed to assess the causal relationship between mtDNA copy number and AD. Genome-wide association study (GWAS) for mtDNA copy number were obtained from the UK Biobank (UKBB), while those associated with AD were sourced from the FinnGen Biobank. Inverse variance weighting (IVW) was the primary analysis method, complemented by three sensitivity analyses (MR-Egger, weighted median, weighted mode) to validate the results. IVW MR analysis identified significant associations between mtDNA copy number and CD (OR=2.51, 95% CI 1.56-4.22, P<0.001), JRA (OR=1.87, 95% CI 1.17-7.65, P=0.022), RA (OR=1.71, 95%CI 1.18-2.47, P=0.004), thyrotoxicosis (OR=0.51, 95% CI0.27-0.96, P=0.038), and T1DM (OR=0.51, 95% CI 0.27-0.96, P=0.038). Sensitivity analyses indicated no horizontal pleiotropy. Our study revealed a potential causal relationship between mtDNA copy number and ADs, indicating that these markers may be relevant in exploring new therapeutic approaches.

Association Between Arterial Stiffness Index and Age-Related Diseases: A Mendelian Randomization Study.

Arterial stiffness is an emerging indicator of cardiovascular risk, but its causal relationship with a variety of age-related diseases is unclear. The objective is to assess the causal relationship between arterial stiffness index (ASI) and age-related diseases by Mendelian randomization (MR) analysis. We obtained instrumental variables associated with age-related diseases from genome-wide association studies (GWAS) of 484,598 European individuals, and data for ASI were obtained from the UK Biobank GWAS of 127,127 participants. We used the inverse variance-weighted as the primary analysis method. In addition, several sensitivity analyses including MR-Egger, weighted-median (WM), Mendelian randomization pleiotropy residual sum and outlier, and Cochran's Q test were performed to test the robustness of the results. Reverse MR analysis was also performed to assess reverse causal relationships between age-related diseases and ASI. We verified the causal relationship between eight age-related diseases and ASI, of which cardiovascular disease (β = 0.19), gallbladder disease (β = 0.85), liver, biliary, or pancreas problem (β = 1.02), hypertension (β = 0.19), joint disorder (β = 0.53), and esophageal disorder (β = 2.10) elevated ASI. In contrast, hyperthyroidism or thyrotoxicosis (β = -2.17) and bowel problems (β = -1.83) may reduce ASI. This MR analysis reveals causal relationships between ASI and several age-related diseases. ASI is expected to be a potential indicator of health conditions for older populations.

Genetic Determinants of Telomere Length and Risk of Aneurysmal Subarachnoid Hemorrhage: A Bidirectional Two-Sample Mendelian Randomization Study

Background Our objective is to investigate the potential causal relationship between telomere length (TL) and aneurysmal subarachnoid hemorrhage (aSAH) and intracranial aneurysms (IAs) by conducting a bidirectional two-sample Mendelian Randomization (MR) study. Methods We utilized publicly available summary data from genome-wide association studies (GWAS) for comprehensive analysis. Telomere length-associated data were sourced from the Epidemiology Unit (IEU) GWAS database (n = 472,174), while data pertaining to intracranial aneurysms were derived from a GWAS meta-analysis conducted by Bakker et al, encompassing aneurysmal subtypes including aSAH (n = 77,074), IAs (n = 79,429), and unruptured intracranial aneurysms (uIA) (n = 74,004), all sampled from European populations. The primary method for MR analysis employed was the Inverse Variance Weighted (IVW) method. Additionally, we conducted various sensitivity analyses to assess the heterogeneity and pleiotropy of study findings. Reverse MR analysis was employed to explore potential reverse causality. Results In the forward MR analysis, the IVW method indicated a negative association between TL and aSAH (OR = 0.636, 95% CI: 0.459–0.883, p = 0.006) as well as IAs (OR = 0.670, 95% CI: 0.499–0.900, p = 0.0079). There was no evidence of heterogeneity or horizontal pleiotropy in the forward MR analysis. Reverse MR analysis did not reveal any causal relationship between aSAH, IAs, uIA and TL. Conclusions In European populations, there exists a causal relationship between longer TL and reduced risks of aSAH and IAs Further research is warranted to elucidate the underlying mechanisms and the potential of TL as an intervention target for lowering the incidence of aSAH and IAs.

Assessing the causal relationship between non-small cell lung cancer and sepsis: a Mendelian randomization study

BackgroundA Two-sample Mendelian randomization (MR) Analysis was used to assess the causal relationship between non-small cell lung cancer (NSCLC) and sepsis.MethodSingle nucleotide polymorphisms (SNPs) closely associated with NSCLC were utilized as instrumental variables (IVs) in this study. The Inverse Variance Weighted (IVW) method was used as the primary method for MR analysis, supplemented by the Weighted median, Weighted model, and MR-Egger regression method. Sensitivity analysis was conducted to improve result robustness, and data from various sources were validated and integrated. Bonferroni tests were applied to adjust for multiple comparisons.ResultsAfter Bonferroni tests correcting the combined results, MR analysis revealed a significant association between genetically predicted NSCLC and an increased susceptibility to sepsis (odds ratios [OR]: 1.140, 95% confidence interval [CI]: 1.085–1.199, P = 2.61 × 10− 7). The combined results demonstrated that NSCLC is associated with a heightened risk of sepsis in patients under 75 years of age (OR: 1.085, 95%CI: 1.037–1.353, P = 3.84 × 10− 4). Furthermore, lung adenocarcinoma (LUAD) was found to be potentially associated with an increased susceptibility to sepsis (OR: 1.040, 95% CI: 1.009–1.073, P = 1.16 × 10− 2). These results withstood multiple sensitivity analyses, demonstrating their robustness.ConclusionThis study confirms that NSCLC can significantly increase susceptibility to sepsis at the genetic level, providing valuable insights for the early identification of individuals at risk for sepsis.

Systematic evaluation of the correlation between serum metabolites and tinnitus

Objective: We performed a Mendelian randomisation (MR) analysis to explore the relationship between serum metabolites and tinnitus. Methods: In this study, 486 serum metabolites were considered as exposure factors, and single nucleotide polymorphisms (SNP) significantly associated with them were used as instrumental variables (IV). The serum metabolite data were obtained from a public database (http://metabolomips.org/gwas/index.php), while the genome-wide association study (GWAS) summary association statistics for tinnitus were obtained from a Finnish database (https://r10.finngen.fi/pheno/H8_TINNITUS). The inverse variance weighting (IVW) method was employed as the primary determination method for MR analysis, with corrections for multiple comparisons made using the false discovery rate (FDR). Sensitivity tests were conducted using the MR-Egger regression, Mendelian random polymorphism residuals and outliers (MR-PRESSO) methods. The identified serum metabolites were subjected to chained disequilibrium regression analysis (LDSC) and metabolic pathway analysis. Reverse MR analysis was performed to investigate the possibility of reverse causality. Analyses were performed in R software (version 4.3.1). Results: A total of 17 serum metabolites (including 10 known and 7 unknown metabolites) associated with tinnitus were identified. The known metabolites included protective metabolites such as acetylcarnitine, hydroxyisovaleryl carnitine, glycine, monounsaturated glycerol ester, and glycine-L-valine, and hazardous metabolites such as allantoin, glycerylphosphorylcholine 1-eicosatrienoate, myo-inositol, 15-methylpalmitate, and pseudouridine; the strongest causally protective metabolites were acetylcarnitine, the followed by hydroxyisopentanoyl carnitine and glycine; the hazardous metabolite with the strongest causal effect was pseudouridine, followed by inositol and 15-methylpalmitate; and only hydroxyisopentanoyl carnitine (PFDR=0.04) and glycerol monooleate (PFDR=0.04) reached significance values after FDR correction. The findings were free of heterogeneity, pleiotropy and reverse causal associations. The metabolic pathways were mainly enriched in pathways such as ascorbic acid and aldolac metabolism. Conclusions: The study suggests a causal relationship between serum metabolites and tinnitus risk. Serum metabolite levels may influence tinnitus-related metabolic pathways.

Investigating the relationship between blood metabolites and diabetic retinopathy using two-sample mendelian randomization and in vivo validation

We addressed fundamental questions about the influence of metabolites on the development of Diabetic retinopathy (DR), and explored the related pathological mechanism. Genome-wide association study (GWAS) database data for metabolites and DR were used to perform Mendelian randomization (MR) studies. The inverse variance weighting (IVW) was chosen as the primary analysis method. Sensitivity analysis was conducted using MR-PRESSO, leave-one-out and Cochran’s Q test. Confounding factors were eliminated to ensure robustness. We also conducted metabolic pathway analysis. In vivo experimental validation was conducted using Sprague Dawley rats. The serum metabolites of the DR group rats and normal group rats were examined to evaluate the MR results. The screen identified eighteen metabolites associated with DR risk, twelve of which were known components. Seven metabolites were positively correlated with DR risk, while five could reduce it. Eight metabolites associated with proliferative DR (PDR) risk were identified, four of which are known components. Three of these were positively associated with PDR risk and one metabolite reduced PDR risk. Additionally, two possible metabolic pathways involved in the biological mechanism of DR were identified. The ELISA results showed that the serum levels of isoleucine and 4-HPA were significantly increased in DR rats, while the level of inosine was decreased. This study offers novel insights into the biological mechanisms underlying DR. Metabolites that are causally linked to DR may serve as promising biomarkers and therapeutic targets.

Causal associations between type 2 diabetes mellitus, glycemic traits, dietary habits and the risk of pressure ulcers: univariable, bidirectional and multivariable Mendelian randomization.

Previous research has established a connection between Type 2 Diabetes Mellitus (T2DM), glycemic traits, dietary habits, and the risk of Pressure Ulcers (PUs). The aim of our study is to disentangle any potential causal relationship between T2DM, glycemic traits, and dietary factors, and the risk of PUs. The exposure and outcome datasets were sourced from the IEU Open GWAS project, the Meta-Analyses of Glucose and Insulin-related traits Consortium (MAGIC), and the FinnGen biobank, respectively. The primary MR analysis method employed was the inverse variance-weighted method. Furthermore, we employed multivariable MR (MVMR) adjusting for BMI. Then, we investigated the possibility of a reverse association between glycemic traits and PUs through bidirectional MR. Finally, Heterogeneity and pleiotropic analysis were conducted to ensure the accuracy and robustness of the results. The findings revealed that T2DM (OR = 1.282, 95% CI: 1.138-1.445, p < 0.001) and Fasting Glucose (FG; OR = 2.111, 95% CI: 1.080-4.129, p = 0.029) were associated with an increased risk of PUs, while salad/raw vegetable intake (OR: 0.014; 95% CI: 0.001-0.278; p = 0.005) was identified as a protective element. However, no other dietary elements demonstrated a statistically significant causality with PUs. In addition, in the reverse direction, there were positive correlation between genetic susceptibility to PUs and an increase in FG (OR: 1.007, 95% CI: 1.000-1.013, p = 0.048) and Fasting Insulin (FI; OR: 1.012, 95% CI: 1.003-1.022, p = 0.011). MVMR results indicated that the causal effect of T2DM on PUs was independent of BMI (OR: 1.260, 95% CI: 1.112-1.427, p < 0.001). These results remained robust when considering weak instrument bias, pleiotropy, and heterogeneity. This study establishes a causal link between genetically predicted T2DM, FG and an increased risk of PUs. Conversely, Salad/raw vegetable intake is significantly inversely associated with PUs. Simultaneously, we identified two downstream effector factor (FG and FI) that were associated with PUs. These findings may have clinical implications for both prevention and treatment.

Periodontitis and Hepatocellular Carcinoma: A Two-Sample Mendelian Randomisation Study

Introduction and AimsObservational studies have reported conflicting associations between periodontitis (PD) and hepatocellular carcinoma (HCC). To overcome these limitations, we performed a two-sample Mendelian randomization (MR) analysis to investigate the potential association between PD and HCC. MethodsWe used summary data from genome-wide association studies (GWASs) of European ancestry, integrating data from chronic/acute periodontitis (CP/AP) samples (n1 = 34,615; n2 = 277,036; n3 = 410,811) and HCC samples (n1 = 456,348; n2 = 475,638). The inverse variance-weighted (IVW) approach represents our primary analysis method, supplemented by MR-Egger regression, weighted median, weighted-mode, and simple-mode methods. Pleiotropy and heterogeneity tests were also performed. ResultsIVW analysis suggested that PD had no effect on HCC (Group 1: odds ratio [OR] = 0.912, 95% confidence interval [CI] = 0.690-1.204, P = .514; Group 2: OR = 1.038, 95% CI = 0.895-1.203, P = .623; Group 3: OR = 0.966, 95% CI = 0.851-1.096, P = .591; Group 4: OR = 1.103, 95% CI = 0.576-2.113, P = .768; Group 5: OR = 1.257, 95% CI = 0.511-1.037, P = .540; Group 6: OR = 0.728, 95% CI = 0.511-1.037, P = .079). Four complementary analyses further support this conclusion. Both the IVW and MR-Egger results indicate that the instrumental variables in each group did not exhibit significant pleiotropy. MR-Egger regression analysis showed no evidence of pleiotropic effects. ConclusionOur MR analysis suggests that PD does not significantly impact the risk of developing HCC. These results provide a new perspective on the relationship between these 2 conditions. Clinical RelevanceThis MR study suggests no significant genetic causal relationship between PD and HCC, providing a new perspective. It indicates that clinicians may not need to over-intervene in periodontal disease to prevent liver cancer, thereby avoiding unnecessary psychological burden on patients.

Inflammatory cytokines and their potential role in kidney stone disease: a Mendelian randomization study.

Previous studies have reported a complex relationship between inflammatory cytokines and kidney stone disease (KSD). The purpose of this paper is to investigate the potential causal impact of inflammatory cytokines on KSD by Mendelian randomization (MR) analysis. In our study, a thorough two-sample Mendelian randomization (MR) analysis was performed by us to determine the potential causal relationship between inflammatory cytokines and kidney stone disease. Utilizing GWAS summary data of inflammatory cytokines and KSD, we performed the first two-sample MR analysis. Genetic variants in GWASs related to inflammatory cytokines were employed as instrumental variables (IVs). The data on cytokines were derived from 14,824 participants and analyzed by utilizing the Olink Target-96 Inflammation Panel. GWAS summary data related to KSD (9713 cases and 366,693 controls) were obtained from the FinnGen consortium. The primary MR analysis method was Inverse variance weighted. Reverse MR analysis, Cochran's Q test, MR Egger, and MR-Pleiotropy RESidual Sum and Outlier (MR-PRESSO) were used to assess the stability of the results. 91 cytokines were enrolled in the MR analysis after strict quality control of IV. The IVW analysis revealed 2 cytokines as risk factors for KSD: Cystatin D (OR 1.06, 95% CI 1.01-1.11), Fibroblast growth factor 5 (OR 1.06, 95% CI 1.00-1.12), suggesting they are positively associated with the occurrence of kidney stones. We also found 3 protective associations between cytokines and KSD: Artemin (OR 0.86, 95% CI 0.78-0.96), T-cell surface glycoprotein CD6 isoform (OR 0.92, 95% CI 0.88-0.98), STAM-binding protein (OR 0.83, 95% CI 0.69-0.99). There was no horizontal pleiotropy or significant heterogeneity in our MR analysis, as determined by the p-value results of our MR Egger's intercept test, Cochrane Q-test, and MR-PRESSO, which were all > 0.05. Our study explored a variety of inflammatory cytokines related to KSD through MR analysis, which validated several previous findings and provided some new potential biomarkers for KSD. However, the findings require further investigation to validate their exact functions in the pathogenesis and evolution of KSD.

Causal relationship between circulating immune cells and gastric cancer: a bidirectional Mendelian randomization analysis using UK Biobank and FinnGen datasets.

The role of immune cells in cancer pathogenesis remains controversial due to conflicting reports, potentially arising from various confounding factors. Emerging evidence suggests that cancer can also influence immune cell populations and functions, making it challenging to investigate their causal relationship. Traditional observational studies often fail to eliminate all confounding factors and are prone to reverse causality. Therefore, we employ Mendelian randomization (MR) to determine the causal relationship between immune cells and cancer, as this method can identify causal relationships independent of confounding factors and avoid reverse causality. Genome-wide association study (GWAS) summary statistics on immune traits, encompassing 310 immune cell phenotypes, were obtained from 3,757 European individuals, with peripheral blood immune cells tested using flow cytometry. GWAS summary statistics for gastric cancer were derived from 476,116 European individuals across two large-scale biobanks: the UK Biobank and FinnGen. Gastric cancer was identified by the International Classification of Diseases, 9th Revision (ICD-9), and 10th Revision (ICD-10) codes. Significant single nucleotide polymorphisms (SNPs) for immune traits were extracted at a threshold of P<1×10-5, while a threshold of P<5×10-8 was used for gastric cancer GWAS data. Linkage imbalance-based clumping was performed to obtain independent SNPs, and those with F<10 were excluded to mitigate weak instrument bias. Phenoscanner V2 was used to exclude SNPs directly associated with potential confounders or outcomes. Two-sample MR was conducted using five MR methods, with inverse-variance-weighted (IVW) as the primary analysis method. A false discovery rate (FDR) correction was used to reduce the likelihood of type 1 errors. In addition, we conducted MR-Egger intercept tests and Cochran's Q tests. The numbers of CD4-CD8- T cells and IgD-CD27- B cells were positively correlated with the development of gastric cancer, with odds ratios (ORs) of 1.15 [95% confidence interval (CI), 1.07-1.24; P<0.001; PFDR=0.041; IVW method] and 1.07 (95% CI, 1.03-1.11; P=0.001; PFDR=0.187; IVW method), respectively. However, the percentage of IgD+CD24- B cells in lymphocytes were negatively associated with the development of gastric cancer (OR =0.90; 95% CI, 0.84-0.96; P=0.002; PFDR=0.187; IVW method). MR analysis of the above three immune cell phenotypes showed no significant heterogeneity or horizontal pleiotropy. In the reverse MR analysis, gastric cancer was not causally associated with any of the immune cell phenotypes. Circulating CD4-CD8- T cells and IgD-CD27- B cells are positively correlated with the development of gastric cancer, while the percentage of IgD+CD24- B cells in lymphocytes are negatively correlated. These findings provide insight into the relationship between immune cells and gastric cancer pathogenesis and may serve as a basis for the development of immunotherapies for gastric cancer.