Genetically predicted C-reactive protein mediates the association between rheumatoid arthritis and atlantoaxial subluxation

Immune cells mediate the effect of plasma lipidomes on IgA nephropathy: a Mendelian randomization study

BACKGROUND

IgA nephropathy (IgAN) is a leading cause of chronic kidney disease, often associated with dyslipidemia and immune dysfunction. This study employs Mendelian randomization (MR) to investigate the causal relationship between plasma lipidomes and IgAN, with a focus on the potential mediating role of immune cells.

METHODS

We analyzed the 179 genetically predicted plasma lipidomes and the IgAN gene using two-sample Mendelian randomization (TSMR) and multivariable MR based on summary-level data from a genome-wide association study, and the results were validated by liquid chromatography-mass spectrometry. Furthermore, we quantified the proportional effect of immune cell-mediated lipidomes on IgAN using TSMR.

RESULTS

This study identified significant causal relationships of 3 lipidomes on IgAN risk by examining 179 lipidome traits as exposures. To investigate whether the impact of the 3 lipid groups on IgAN is specific, we performed TSMR analyses using 3 lipidomes as exposure factors and 4 nephritides as outcomes. Specifically, only phosphatidylinositol (18:1_20:4) was found to have a significant negative relationship with IgAN incidence (IVW method, p = 0.01, OR = 0.71, 95% CI = 0.55 - 0.92). Our further analysis focused on 8 immune cells associated with IgAN. We identified 2 immune cell phenotypes that may contribute to phosphatidylinositol (18:1_20:4)-mediated IgAN by careful screening.

CONCLUSIONS

Our findings provide robust genetic evidence supporting a causal link between plasma lipidomes and IgAN, with immune cells acting as potential mediators. Phosphatidylinositol (18:1_20:4) emerges as a promising biomarker for IgAN risk stratification, early detection, and therapeutic intervention. Modulating its plasma levels may offer novel avenues for IgAN management.

Dissecting the role of metformin in urogenital malignancies

Metformin has shown great potential for anti-tumor therapy according to laboratory results, but there is currently no consensus on the role it playing in the pathogenesis of urogenital malignancies. Initially, a systematic review was conducted on clinical research examining the association between the use of metformin and the incidence and prognosis of prevalent urogenital malignancies. Then, a retrospective analysis of the participants in NHANES was performed to strengthen the study. Given the distinct methodological advantages of Mendelian randomization (MR) in research design, whereby genetic variations influencing the exposure of interest are independent of potential confounders, available GWAS data were thoroughly collected and utilized in a two-sample MR analysis to assess the causal relationships between metformin use and various urogenital malignancies. The review of literature demonstrated inconsistencies and ambiguities in clinical findings. The retrospective analysis of 20,527 participants in the NHANES did not reveal strong evidence in the four urogenital malignancies. The current MR study indicates that metformin use is unlikely to be a causal factor in the development of five urogenital malignancies (P > 0.05), either does the reverse MR analysis (P > 0.05). Nevertheless, the results were reliable to some extent since neither heterogeneity nor pleiotropy was detected in most cases. This study suggests that metformin use does not demonstrate a protective effect on the studied urogenital malignancies, contradicting the positive results observed in laboratory settings. Additional evidence from clinical studies is required to validate this conclusion.

Identification of immune cells and circulating inflammatory factors associated with neurodevelopmental disorders by bidirectional Mendelian randomization and mediation analysis

The roles of various immune cells and circulating inflammatory factors in neurodevelopmental disorders (NDDs) remain controversial. Therefore we employed a two-sample and bidirectional Mendelian randomization and mediation method to explore the causal relationships between immune cells, circulating inflammatory factors, and NDDs. All data were originated from Genome-Wide Association Study (GWAS) datasets. We found a significant positive causal relationship between 13 immune cells and autism spectrum disorder (ASD), including six CD8+ T cells, one CD3+ T cell, two CD20+ B cells, one CD38+  B cell, and two plasmacytoid DC. 9 inflammatory factors showed significant causal relationships with ASD: interleukins-7 (IL-7), interleukins-2 (IL-2), Interleukin-2 receptor subunit beta levels( IL-2β) and interleukins-18 receptor 1 levels (IL-18-R1) were negatively associated. In contrast, five inflammatory factors were positively associated, such as tumor necrosis factor-α (TNF-α). 14 immune cells exhibited significant causal relationships with attention deficit hyperactivity disorder (ADHD). CD3 on naive CD8br and CD4 on activated Treg were positively associated, while four CD27-expressing B cells were positively associated with ASD. Four CD40-expressing monocytes were negatively associated with ADHD. 7 inflammatory factors had significant causal relationships with ADHD: Fibroblast Growth Factor 23 levels (FGF-23), CD40L receptor levels, Glial Cell Line-Derived Neurotrophic Factor levels (GDNF), TNF-α were more important among these. Mediation analysis identified 12 mediating relationships, with three showing strong evidence: Natural killer cell receptor 2B4 levels (19.9%), FGF-23 (11%), and Eotaxin levels (- 5.95%). Strong causal relationships existed between immune cells, circulating inflammatory factors, and NDDs. Inflammatory factors mediated the pathways between immune cells and NDDs.

Effects of different types of milk consumption on type 2 diabetes and the mediating effect of AA: A Mendelian randomization study of East Asian populations

There is currently a lack of research examining the association between the consumption of different dairy products and type 2 diabetes (T2D) in East Asian populations. To address this gap, the present study employs Mendelian randomization to investigate the potential effects of 3 different types of milk consumption (including whole milk, semi-skim milk, and skim milk) on the risk of developing T2D. The results indicate that both whole milk and skim milk are associated with an increased risk of T2D (whole milk: odds ratio [OR] = 1.022, 95% CI: 1.001-1.044; skim milk: OR = 1.023, 95% CI: 1.007-1.039). Mediation analysis revealed that asparagine acts as a mediator between skim milk consumption and T2D, with a mediation effect of 0.003 (95% CI: 0.000 to 0.008), accounting for 14.269% of the total effect.

Exploration of the relationships between immune cells, metabolic mediators, and atrial fibrillation: A bidirectional Mendelian randomization study

Studies have shown a close correlation among immune cells, plasma metabolites, and atrial fibrillation (AF). However, it is not clear if this association is related, which we used Mendelian randomization (MR) to investigate. We analyzed the association between immune cells, plasma metabolites, and AF by using summarized data from genome-wide association studies. Among them, we explored the associations between immune cells and AF by using bidirectional MR analysis. Combined with mediation analysis and multivariable MR, we further identified potential mediating plasmic metabolites. Results shows that causal relationships between 8 immune cell phenotypes and AF were identified with all 8 exhibiting reverse causality. Furthermore, 22 plasma metabolites have a causal relationship with AF. In addition, 2 immune cell phenotypes including CD25 on IgD + CD38dim and CX3CR1 on CD14 + CD16-monocyte, which were found to have causal relationships with 4 plasma metabolites, including 4-acetamidobutanoate levels, Octadecanedioylcarnitine (C18-DC) levels, Linolenate [alpha or gamma; (18:3n3 or 6)] levels, and N-acetyl-aspartyl-glutamate levels, which might be mediators. Ultimately, only 4-acetamidobutanoate levels, CD25 on IgD + CD38dim, and AF did appear to function as mediators (P-value = .030 < .05). In conclusion, immune cells and plasma metabolites are causally associated with AF. We have identified that 4-acetamidobutanoate levels appear to mediate the pathway linking CD25 on IgD + CD38dim to AF. This finding provides a new perspective for the early prevention and diagnosis of preatrial AF.

Bidirectional causal relationships between the skin microbiome and psoriasis: Insights from Mendelian randomization analysis

Psoriasis is a chronic inflammatory skin disease affecting 2% of the global population. Recent research suggests the skin microbiome plays a critical role in psoriasis. Skin microbiome data were obtained from the KORA FF4 study in Germany, and psoriasis data from FinnGen genome-wide association study summary statistics. Forward and reverse 2-sample Mendelian randomization (MR) analyses were conducted to assess causal relationships. Forward MR analysis identified several microbial features as risk factors for psoriasis, including the family Neisseriaceae in sebaceous skin (OR = 1.036, 95% CI: 1.010-1.062, P = .0054), ASV011 in dry skin (OR = 1.024, 95% CI: 1.000-1.048, P = .0490), and the order Clostridiales in moist skin (OR = 1.016, 95% CI: 1.000-1.032, P = .0449). Protective features included ASV016 (OR = 0.972, 95% CI: 0.949-0.994, P = .0136) and ASV053 (OR = 0.973, 95% CI: 0.954-0.992, P = .0054) in dry skin. Reverse MR analysis confirmed psoriasis as a significant risk factor for changes in the skin microbiome, with notable associations in the dry skin region for asv002 (OR = 1.266, 95% CI: 1.061-1.510, P = .027) and genus: Haemophilus (OR = 1.364, 95% CI: 1.065-1.746, P = .013). This study reveals bidirectional causal relationships between the skin microbiome and psoriasis, highlighting specific microbial features such as Neisseriaceae and Clostridiales as potential risk factors. Further research is needed to develop treatments that modulate the skin microbiome to improve psoriasis outcomes.

Mendelian randomization evidence for lung function mediates the association between childhood allergies (age <16 years) and essential hypertension

Objective

This study aimed to investigate the influence of lung function on the relationship between allergies and hypertension, thereby elucidating significant potential mechanisms from a genetic standpoint. We investigated the causal relationship between childhood allergies (age <16 years) and essential hypertension and identified and quantified the role of lung function (forced vital capacity [FVC] and forced expiratory volume in the first second/forced vital capacity [FEV1/FVC]) as potential mediators.

Methods

Using data from a genome-wide association study and the Fenn Genn consortium, a two-sample Mendelian randomization (MR) analysis of genetically predicted childhood allergies (7128 cases and 211,703 controls) and essential hypertension (116,714 cases and 1,032,659 controls) was performed. Furthermore, we used two-step MR to quantify the effect of lung function-mediated childhood allergies on essential hypertension. The FVC and FEV1/FV sample size was 371,898.

Results

Childhood allergies were associated with increased odds of developing essential hypertension (odds ratio [OR] = 1.0900, 95% confidence interval [CI] =   1.0034-1.1842, P = 0.0414). No strong evidence that genetically predicted essential hypertension affected childhood allergy risk was identified (OR = 1.0631, 95% CI = 0.9829-1.1498, P = 0.1264). The proportion of genetically predicted childhood allergies mediated only by FVC was 5.67% (95% CI, 5.13%-5.73%).

Conclusion

A causal relationship between childhood allergies and essential hypertension was identified, with a proportion of the effect mediated by FVC. Therefore, implementing early interventions in children with allergies is imperative to mitigate the long-term risk of developing hypertension. Further research is required to identify additional risk factors as potential mediators.

Genetic Prediction of the Phosphate-to-Glucose Ratio Mediates the Association Between CXCL5 and Vascular Dementia

BACKGROUND AND OBJECTIVES

A variety of observational studies suggest a possible connection between C-X-C Motif Chemokine Ligand 5 (CXCL5) and vascular dementia (VaD), though the exact causal relationship is still uncertain. This research aims to investigate the causal connection between CXCL5 and VaD risk through a Mendelian randomization (MR) method and to examine the phosphate-to-glucose ratio as a possible mediator.

METHODS

Using summary-level data from genome-wide association studies (GWAS), we conducted a two-sample MR analysis to investigate the genetic prediction of CXCL5 and VaD. Horizontal pleiotropy, heterogeneity, and sensitivity analyses were also performed on the MR findings. Additionally, a two-step MR was utilized to quantify the proportion of the effect of CXCL5 on VaD mediated by the phosphate-to-glucose ratio.

RESULTS

MR analysis identified that higher levels of CXCL5 (IVW: p = 0.022, OR = 1.265, 95% CI = 1.034-1.547) increase the risk of VaD. Tests for horizontal pleiotropy (p > 0.05), heterogeneity (p > 0.05), and sensitivity analyses supported these findings. There is insufficient robust evidence to suggest that genetic predispositions for VaD have any significant impact on CXCL5 (IVW: p = 0.254). The phosphate-to-glucose ratio accounted for 11.1% of increase in the risk of VaD associated with CXCL5 (95% CI = -12.3% to 34.5%).

CONCLUSION

To conclude, our research confirms a causal link between CXCL5 and VaD and shows that the ratio of phosphate-to-glucose plays a mediating role in a segment of the risk effect of CXCL5 on VaD. However, most of the effects of CXCL5 on VaD are still not well understood. Additional studies are necessary to explore other potential mediators as risk factors. In clinical settings, individuals with abnormally elevated CXCL5 may need to be monitored for an increased risk of developing VaD.

Blood Metabolome Mediates the Effect of the Plasma Lipidome on the Risk of Atrial Fibrillation: A Mendelian Randomization Study

BACKGROUND AND OBJECTIVE

Atrial fibrillation (AF), a common arrhythmic disorder, is increasing in prevalence annually and has become an important public health problem that jeopardizes human health. Metabolites are small molecules produced in the process of metabolic reactions, and they can affect the risk of disease and possibly become targets for disease management.

METHODS

We used two-sample and bidirectional MR to explore potential causal associations between lipid groups and AF. Two-step MR analysis was used to explore whether plasma metabolites mediated a causal effect from lipidomes to AF.

RESULT

We assessed the effect of 179 lipids on AF using IVW models and observed that 8 lipids were associated significantly with AF (p < 0.05). Likewise, we assessed the effect of 1091 metabolites and 309 metabolite ratios on AF and observed that 22 metabolites were significantly associated with AF (p < 0.05). We analyzed the blood metabolites above as mediators in the pathway from the lipidomes above to AF. We found that levels. Of lipid sterol ester (27:1/18:3) were associated with lower homoarginine levels, and lower metabolite homoarginine levels were associated with an increased risk of AF.

CONCLUSION

Our study identified a causal relationship between plasma liposomes and AF, and additionally found that the plasma metabolite homoarginine levels can act as a mediator of the lipid sterol ester in its effect on AF.

From gut to kidney: microbiota modulates stone risk through inflammation-a mediated Mendelian randomization study

The gut microbiota (GM) can affect the immune system, which can lead to a variety of diseases, as confirmed by many studies. However, the exact mechanism by which GM affects kidney stone incidence through the immune system remains unclear. This study used a two-step, two-sample Mendelian randomization (MR) analysis by inverse variance weighting (IVW) method as well as Bayesian weighting (BWMR) to find out how the gut microbiota and inflammatory cytokines contribute to kidney stones, followed by a mediated MR analysis to exploreHow inflammatory cytokines are involved in the connection with the gut microbiota and kidney stones. MR analysis revealed that seven intestinal flora were protective against kidney stones, including family. Actinomycetaceae, family.Clostridiaceae1, genus.Clostridiumsensustricto1, genus. Hungatella, genus.LachnospiraceaeUCG001, genus.LachnospiraceaeUCG008 and order. Actinomycetales, while four intestinal flora, including genus. Haemophilus, genus. RuminococcaceaeUCG010, order.Rhodospirillales and phylum.Actinobacteria may increase the risk of kidney stones. In addition, it was confirmed that seven Inflammatory cytokines DNER, IL-18, IL-1α, SLAMF1, STAMPB, CST5 and FGF-5 in association with kidney stones. Notably, the mediating MR indicated the causal effect of phylum. Actinobacteria and order. Rhodospirillales gut group on kidney stones was mainly modulated by IL-18 levels, with mediating effects accounting for 15.8% and 12.8% of the total effect, respectively. The present study demonstrates this phylum. Actinobacteria and order. Rhodospirillales flora have an important role in reducing the risk of kidney stones and act mainly by modulating IL-18 levels.

Investigating the causal relationship between the gut microbiome and rheumatoid arthritis: mediating effects of immune cells

BACKGROUND

Rheumatoid arthritis (RA) is a complex autoimmune and inflammatory disease that significantly impacts the quality of life for millions worldwide. In recent years, gut microbiota has garnered extensive attention as a potential health-modulating factor, with associations identified between it and various diseases, including RA. This study aims to investigate the causal relationship between gut microbiota and RA using Mendelian Randomization (MR) analysis, and further examines the mediating role of immune cells in this connection.

METHOD

A MR analytical method was employed by us, integrating genome-wide association study (GWAS) data from FinnGen, MiBioGen, and research led by Valeria Orrù and her team to systematically examine the relationships between gut microbiota, immune cells, and RA. Initially, we performed a bidirectional univariable MR analysis to examine the relationship between gut microbiota and RA, consciously avoiding any possible reverse causal influences. Following this, we applied multivariable MR adjustments on gut microbiota that showed positive associations and employed a two-step methodology to examine the overall genetic predictive role of immune cell-mediated gut microbiota in the risk of developing RA.

RESULT

Our results demonstrate notable causal connections between different gut microbiota and RA. In particular, Mollicutes, Ruminococcaceae UCG002, and Butyricimonas displayed positive associations with RA, while other microbiota, including Rikenellaceae, Lactobacillaceae, and Veillonella, showed negative associations. Additionally, we identified a reduction in the abundance of certain microbiota, including Lachnospiraceae and Ruminococcus1, which were excluded from our study and validated for analytical accuracy using methods such as "leave-one-out." Immune cells, including CD3 found on activated CD4 regulatory T cells that express CD39, serve a mediating function in the development of RA. To summarize, our research focused on the species Butyricimonas id. 945, recognizing immune cells as crucial contributors to the relationship between genetic predictions of gut microbiota and RA.

CONCLUSION

This research clarifies the intricate causal links between gut microbiota and RA, emphasizing the crucial mediating function of immune cells in this mechanism. These findings not only enhance our understanding of the pathogenesis of RA but also provide new perspectives and potential intervention targets for future prevention and treatment strategies. Future research should further investigate the specific mechanisms underlying the interactions among gut microbiota, immune cells, and RA, while considering the validation of these findings across diverse populations.

Gene prediction of immune cells association between gut microbiota and colorectal cancer: a Mendelian randomization study

Background

An increasing number of studies have revealed that gut microbiota influences the development and progression of Colorectal cancer (CRC). However, whether a causal relationship exists between the two remains unclear, and the role of immune cells in this context is not well understood.

Objective

To elucidate the causal relationship between gut microbiota and CRC and to explore the potential mediating role of circulating immune cells.

Materials and methods

To analyze the causal relationship between gut microbiota and CRC, we employed a univariable Mendelian randomization (UVMR) approach. Subsequently, a two-step multivariable Mendelian randomization (MVMR) to assess the potential mediating role of circulating immune cells. Primarily, applied the Inverse-Variance Weighted method to evaluate the causal relationship between exposure and outcome. To ensure the robustness of the results linking gut microbiota and CRC, we validated the findings using Robust Inverse-Variance Weighted, Penalized Inverse-Variance Weighted, and Penalized Robust Inverse-Variance Weighted methods. Additionally, we employed MR-Egger Intercept to mitigate the influence of horizontal pleiotropy. MR-PRESSO was used to detect and correct outliers by excluding anomalous instrumental variables. Finally, we supplemented our analysis with methods such as Bayesian Weighted Mendelian Randomization (BWMR), Maximum-Likelihood, Lasso, Debiased Inverse Variance Weighted, and Contamination Mixture to establish a robust and compelling causal relationship.

Results

After accounting for reverse causality, horizontal pleiotropy, and various methodological corrections, Bifidobacterium kashiwanohense, GCA-900066755 sp900066755, Geminocystis, and Saccharofermentanaceae exhibited strong and robust causal effects on CRC. Specifically, CD40 on monocytes (2.82%) and CD45 on CD33+HLA-DR+CD14- cells (12.87%) mediated the causal relationship between Bifidobacterium kashiwanohense and CRC risk. Furthermore, CD45 on CD33-HLA-DR+ (3.94%) mediated the causal relationship between GCA-900066755 sp900066755 and CRC risk. Additionally, terminally differentiated CD4+T cells (11.55%) mediated the causal relationship between Geminocystis and CRC risk. Lastly, CD40 on monocytes (2.35%), central memory CD4+T cells (5.76%), and CD28 on CD28+CD45RA+CD8+T cells (5.00%) mediated the causal relationship between Saccharofermentanaceae and CRC risk.

Conclusion

Our mediation MR analysis provides genetic evidence suggesting that circulating immune cells may mediate the causal relationship between gut microbiota and CRC. The identified associations and mediation effects offer new insights into potential therapeutic avenues for CRC.

Role of plasma metabolome in mediating the effect of plasma lipidome on NAFLD: a Mendelian randomization study

Background

This study explored the causal connection among the plasma lipidome, nonalcoholic fatty liver disease (NAFLD), and potential metabolome mediators through Mendelian randomization (MR).

Methods

We obtained summary statistics for 179 plasma lipidome traits (N = 7,174), 1,400 plasma metabolome traits (N = 8,299), and one NAFLD trait from publicly available genome-wide association studies. A two-sample MR analysis was conducted to infer causality. Additionally, multiple sensitivity analyses were conducted to assess the heterogeneity, horizontal pleiotropy, and robustness of the MR findings. MetaboAnalyst 6.0 was used for the pathway analysis of the identified lipids and metabolites. Furthermore, we used mediation analysis to assess whether the effect of plasma lipidome on NAFLD was mediated by plasma metabolome.

Results

The MR analysis predicted a genetically determined causal relationship between plasma lipidomes and NAFLD. No compelling proof was found that genetically predicted NAFLD influenced the risk of the five plasma lipidomes mentioned earlier. Based on established causal relationships between lipids and metabolites, we identified that eight metabolic pathways are closely associated with NAFLD. Our mediation analysis revealed six mediation relationships, indicating the causal pathway from plasma lipids to NAFLD mediated by five specific metabolites. No potential pleiotropy was found in the sensitivity analysis.

Conclusions

In summary, our study identified causal relationships between plasma lipidomes, plasma metabolomes, and NAFLD. Certainly, the impact of plasma lipidomes on NAFLD is not limited to plasma metabolomes, indicating a need to further investigate into other possible mediators. These identified factors may become new biomarkers of the NAFLD contributing to its prevention, diagnosis, and treatment.

Identification of hub genes and immune-related pathways in acute myeloid leukemia: insights from bioinformatics and experimental validation

Background

This study aims to identify the hub genes and immune-related pathways in acute myeloid leukemia (AML) to provide new theories for immunotherapy.

Methods

We use bioinformatics methods to find and verify the hub gene. At the same time, we use the results of GSEA enrichment analysis to find immune-related mediators. Through Mendelian randomization(MR) analysis, on the one hand, we look for related immune cells, and on the other hand, we use it to determine the causal relationship among immune cells, immune mediators, and AML. Finally, in vitro experiments are conducted to further verify and improve the reliability and physiological functions of the hub gene and its immune-related pathways.

Results

Complement Factor D(CFD) gene is identified as the highly expressed hub gene and is positively correlated with IL-2. IL-2 is also positively correlated with CD27 on CD24+CD27+B cells, JAK/STAT, and PI3K/Akt. The latter three are positively correlated with the occurrence and development of AML.

Conclusion

We conclude that CFD gene uses IL-2 as a mediator to promote the disease progression of AML by promoting the CD27 on CD24+CD27+B cells, JAK-STAT, and PI3K-Akt pathways.

Causal relationship between key genes and metabolic dysfunction-associated fatty liver disease risk mediated by immune cells: A Mendelian randomization and mediation analysis

AIM

Non-invasive diagnostics for metabolic dysfunction-associated fatty liver disease (MAFLD) remain challenging. We aimed to identify novel key genes as non-invasive biomarkers for MAFLD, elucidate causal relationships between biomarkers and MAFLD and determine the role of immune cells as potential mediators.

MATERIALS AND METHODS

Utilizing published transcriptome data of patients with biopsy-proven MAFLD, we applied linear models for microarray data, least absolute shrinkage and selector operation (LASSO) regressions and receiver operating characteristic (ROC) curve analyses to identify and validate biomarkers for MAFLD. Using the expression quantitative trait loci database and a cohort of 778 614 Europeans, we used Mendelian randomization to analyse the causal relationships between key biomarkers and MAFLD. Additionally, mediation analysis was performed to examine the involvement of 731 immunophenotypes in these relationships.

RESULTS

We identified 31 differentially expressed genes, and LASSO regression showed three hub genes, IGFBP2, PEG10, and P4HA1, with area under the receiver operating characteristic (AUROC) curve of 0.807, 0.772 and 0.791, respectively, for identifying MAFLD. The model of these three genes had an AUROC of 0.959 and 0.800 in the development and validation data sets, respectively. This model was also validated using serum-based enzyme-linked immunosorbent assay data from MAFLD patients and control subjects (AUROC: 0.819, 95% confidence interval: 0.736-0.902). PEG10 was associated with an increased MAFLD risk (odds ratio = 1.106, p = 0.032) via inverse variance-weighted analysis, and about 30% of this risk was mediated by the percentage of CD11c + CD62L- monocytes.

CONCLUSIONS

The MAFLD panels have good diagnostic accuracy, and the causal link between PEG10 and MAFLD was mediated by the percentage of CD11c + CD62L- monocytes.

Association of SOGPI in mediating the effect of Phosphatidylcholine on polycystic Ovary Syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder in women of reproductive age, marked by hormonal imbalances and disruptions in glucose and lipid metabolism. Emerging research has indicated a correlation between lipids and PCOS, yet the specific lipid profiles or associated genes identified in various studies vary, and observational data alone cannot establish causation. Therefore, our study seeks to establish a causal association between lipidome and PCOS.

METHODS

Data from genome-wide association studies, liposomes, metabolites, and PCOS-related information were collected. Four rounds of double-sample bidirectional intermediate Mendelian Randomization analyses including liposomes to disease, liposomes to metabolites, metabolites to disease, and reverse Mendelian Randomization analysis of lipids, total effect values and intermediary effect values were calculated. The proportion mediated by the intermediary effect was determined by dividing the intermediary effect value by the total effect value.

RESULTS

The analyses revealed that three liposomes and nine metabolites were causally associated with PCOS. Specifically, phosphatidylcholine and 1-Stearoyl-2-Oleoyl-Glycosylphosphatidylinositol were identified as independent risk factors for PCOS through further Mendelian Randomization analysis. The risk of developing PCOS increased by 32% for every one standard deviation increase in phosphatidylcholine and by 17% for every one standard deviation increase in 1-Stearoyl-2-Oleoyl-Glycosylphosphatidylinositol. Furthermore, the study revealed that phosphatidylcholine can influence the development of PCOS with 1-Stearoyl-2-Oleoyl-Glycosylphosphatidylinositol acting as a mediator, explaining 4.97% of the effect.

CONCLUSIONS

This study confirmed a causal relationship between phosphatidylcholine and 1-Stearoyl-2-Oleoyl-Glycosylphosphatidylinositol with PCOS, where phosphatidylcholine can influence the occurrence of PCOS with 1-Stearoyl-2-Oleoyl-Glycosylphosphatidylinositol as a mediator.

Causal relationship between lipidome and acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS), with high morbidity and mortality, is a common clinical syndrome of acute respiratory failure caused by diffuse lung inflammation and edema. ARDS can precipitate in various ways. The complex pathophysiology of ARDS involves the activation and dysregulation of multiple metabolisms and immune responses. Using summary-level data from a genome-wide association study (GWAS), a two-sample Mendelian randomization (MR) analysis of 179 genetically predicted lipid species and ARDS (375 cases, 406,518 controls) was performed and validated in plasma and pulmonary edema fluid from 24 patients. Furthermore, we used a two-step MR to quantify the effect of immune cell-mediated lipids on ARDS. We identified 8 lipids (Cholesterol, Phosphatidylcholine (14:0_16:0), Phosphatidylcholine (16:0_20:5), Phosphatidylcholine (18:0_18:2), Phosphatidylethanolamine (18:1_18:1), Triacylglycerol (51:2), Triacylglycerol (52:4), and Triacylglycerol (54:3) ) associated with ARDS. The proportions of genetically-predicted lipids mediated by the four types of immune cells were determined. Sensitivity analysis did not reveal any obvious pleiotropy or heterogeneity. Our study demonstrates the power of multivariate genetic analysis in correlated lipidomic data and reveals genetic links between ARDS and lipid species beyond standard lipids.

Genetically predicted blood metabolites mediate the association between circulating immune cells and severe COVID-19: A Mendelian randomization study

Investigating the causal relationship between circulating immune cells, blood metabolites, and severe COVID-19 and revealing the role of blood metabolite-mediated circulating immune cells in disease onset and progression. Genetic variation data of 731 circulating immune cells, 1400 blood metabolites, and severe COVID-19 from genome-wide association study open-access database (https://gwas.mrcieu.ac.uk) were used as instrumental variables for bidirectional and two-step Mendelian randomization analysis. The study identified 11 circulating immune cells with unidirectional causality to severe COVID-19. Two-step Mendelian randomization analysis showed 10 blood metabolites were causally associated with severe COVID-19, and blood Myristate and Citrulline to phosphate ratio mediated the association of circulating effector memory double negative % DN and CD8dim natural killer T cell % T cells, respectively, with severe COVID-19 (Myristate mediated effect ratio was 10.20%, P = .011; Citrulline to phosphate ratio mediated effect ratio was -9.21%, P = .017). This study provides genetic evidence assessing the causal relationship between circulating immune cells, blood metabolites, and severe COVID-19, elucidates the role of blood metabolite-mediated circulating immune cells in severe COVID-19 development, and offers new insights into severe COVID-19 etiology and related preventive and targeted therapeutic strategies.

The application of sphingomyelin in mediating the causal role of the T-cell surface glycoprotein CD5 in Crohn's disease: A two-step Mendelian randomization study

To examine the possible causative association between Crohn disease (CD) and the T-cell surface glycoprotein CD5 and to ascertain whether sphingomyelin (SM) functions as a mediator. We conducted a two-step Mendelian randomization (MR) study to further explore the pathogenesis of Crohn and its related targets. MR study was performed on CD5 and CD using summary-level data from a genome-wide association study. Additionally, by employing a two-step MR study method, we determined that SM might mediate the causal effect of CD5 on CD. There was a favorable correlation between the surface glycoprotein CD5 on T cells and vulnerability to CD, and SM mediated the causal effect of CD5 on CD (the mediating effect accounts for 9.2%). Our study revealed that CD5 and CD are causally related, with SM mediating a small fraction of the impact (approximately 9.2%). The mediating function of SM in the link between CD5 and CD is anticipated to be realized through the regulation of immune cell transportation, apoptosis of intestinal barrier cells, and maintenance of the intestinal microenvironment.

Predictive analysis of osteoarthritis and chronic pancreatitis comorbidity: complications and risk factors

Background

The comorbidity of chronic pancreatitis (CP) in patients with osteoarthritis (OA) is insufficiently studied, and the reciprocal impact of these conditions remains poorly understood. This study aimed to investigate potential predictors for the development of CP in OA patients, as well as associated complications.

Methods

A cohort of 181 patients was categorized into four groups: a control group (n=30), patients with OA (n=68), patients with CP (n=31), and patients with OA and comorbid CP (n=52). All four groups had no statistical differences in age and gender. The study utilized the WOMAC index, Visual Analog Scale (VAS), Lequesne index, biochemical assays, and advanced statistical methods to assess joint status in OA patients with comorbid CP. It explored potential predictors of comorbidity development and associated complications.

Results

The study revealed that concurrent CP in OA exacerbates progression and contributes to malnutrition. Body Mass Index (BMI) emerged as a potential predictor for CP comorbidity development in OA patients. Factors such as the WOMAC total score, fecal elastase-1, C-reactive protein (CRP), ferritin, retinol, tocopherol, 25-hydroxyvitamin D3, and BMI were found to influence the development of comorbidity of CP in OA. Additionally, Gastrointestinal Symptom Rating Scale-Diarrhea Syndrome (GSRS-DS), Gastrointestinal Symptom Rating Scale-Constipation Syndrome (GSRS-CS), Qualitative Assessment of the Symptoms and Impact of Pancreatic Exocrine Insufficiency Domain A (PEI-Q-A), retinol, tocopherol, and iron were identified as potential predictors comorbidity CP with exocrine pancreatic insufficiency in OA patients.

Conclusion

The presence of CP in OA patients exacerbates disease progression and complications, necessitating further investigation.

Role of blood metabolites in mediating the effect of gut microbiota on chronic gastritis

Exploring the link between gut microbiota and chronic gastritis (CG), and assessing the potential mediating influence of blood metabolites. Using aggregated data from genome-wide association studies (GWAS), we performed a two-sample Mendelian randomization (MR) analysis to explore the genetic links between gut microbiota (412 types) and CG (623,822 cases). Furthermore, we utilized a two-step MR approach to measure the extent to which blood metabolites (1,400 types) mediate the impact of gut microbiota on CG. Through MR, we identified that three genetically predicted gut microbiota increased the risk of CG: the ubiquinol-8 biosynthesis pathway (OR 1.149, 95%CI 1.022-1.291), Odoribacter from the Porphyromonadaceae family (OR 1.260, 95%CI 1.044-1.523), and Coprococcus from the Lachnospiraceae family (OR 1.125, 95%CI 1.010-1.253). Currently, there is no evidence to suggest that genetically predicted CG affects the risk of gut microbiota. Four blood metabolites mediated the proportionate changes in genetically predicted gut microbiota: levels of 4-hydroxyphenylacetate levels by 14.9% (95% CI -0.559%, 30.3%), palmitoleate (16:1n7) levels, and the phosphate to alanine ratio together mediated the same microbiota by 6.97% (95% CI -1.61%, 15.6%) and 7.91% (95% CI -1.67%, 17.5%), while the phosphate to alanine ratio and X-12839 levels together mediated the same microbiota by 8.48% (95% CI -2.87%, 19.8%) and 10.7% (95% CI 0.353%, 21.1%). In conclusion, our research has confirmed a causal link between gut microbiota, blood metabolites, and CG. Metabolites such as 4-hydroxyphenylacetate levels, palmitoleate (16:1n7) levels, the phosphate to alanine ratio, and X-12839 levels have relatively significant mediating roles between gut microbiota and CG. These metabolites may influence the occurrence and development of CG by regulating inflammatory responses, energy metabolism, and gut barrier function. However, the majority of the influence of gut microbiota on CG remains unclear, necessitating further research into other potential mediating risk factors. Clinically, it is crucial to focus on patients suffering from CG who exhibit dysbiosis of gut microbiota.IMPORTANCEThe results indicate that interactions between particular gut microbiota and blood metabolites may significantly contribute to the onset and progression of CG. These findings offer new insights and potential targets for early diagnosis, personalized treatment, and prevention of CG.

The causal nexus between diverse smoking statuses, potential therapeutic targets, and NSCLC: insights from Mendelian randomization and mediation analysis

Objective

Lung cancer, the most prevalent malignancy, is typically diagnosed at an advanced stage. Smoking is a pivotal risk factor for NSCLC, yet the impact of various smoking statuses on NSCLC remains unclear. Thus, this study aims to explore whether different smoking statuses can causally influence NSCLC through effects on predictive targets, offering a novel perspective for NSCLC treatment.

Methods

Employing dual-sample MR, MVMR, and TSMR approaches, we assessed the causal relationships between 13 distinct smoking statuses and NSCLC, using predicted potential therapeutic targets as mediators to further elucidate the causal interplay among them.

Results

Among the 13 smoking statuses, current tobacco smoking, exposure to tobacco smoke outside the home, past tobacco smoking, and never smoked demonstrated causal relationships with NSCLC. MVMR analysis reveals that Current tobacco smoking is an independent risk factor for NSCLC. Utilizing NCAPD2, IL11RA, and MLC1 as mediators, IL11RA (22.2%) was found to potentially mediate the relationship between past tobacco smoking and NSCLC.

Conclusion

This study, integrating bioinformatics and MR analysis, identified three potential predictive targets as mediators to investigate the causal relationships between different smoking statuses and NSCLC through potential therapeutic targets, providing new insights for the treatment and prevention of NSCLC.

Immune cells mediate the causal relationship between uveitis and colorectal cancer via Mendelian randomization analysis

Colorectal cancer (CRC) is one of the most common and deadly malignancies worldwide, and immune regulation plays a critical role in its development. This study investigates the causal relationships between uveitis, specific immune cell traits, and CRC using Mendelian Randomization (MR) analyses. A total of 21 single nucleotide polymorphisms (SNPs) associated with uveitis were identified, and the analysis revealed that a 1 log-odds increase in uveitis was linked to a statistically significant 3.0% reduction in CRC odds (IVW OR = 0.970, 95% CI: 0.946-0.995, P = 0.021). This protective effect was also observed using the weighted median approach (OR = 0.963, 95% CI: 0.931-0.997, P = 0.034), reinforcing the robustness of the findings. Furthermore, both univariable and multivariable MR analyses highlighted the significant causal influence of specific immune cell traits on CRC odds. Notably, the levels of extracellular monocyte HLA-DR expression emerged as a critical factor, with an associated increase in CRC odds (IVW OR = 1.084, 95% CI: 1.008-1.165, P = 0.030). The proportion of CRC odds mediated by the levels of extracellular monocyte HLA-DR expression, calculated as the ratio of the indirect effect to the total effect using estimates from multivariable MR analyses, was approximately 34.1%(95% CI: 10.23-58.04%). These findings underscore the complex interplay between immune regulation and carcinogenesis, offering insights into potential mechanisms underlying CRC development and suggesting avenues for targeted prevention and therapeutic strategies.

Genetically predicted N-Acetyl-L-Alanine mediates the association between CD3 on activated and secreting Tregs and Guillain-Barre syndrome

Objective

This study sought to explore the potential causal relationships among immune cell traits, Guillain-Barre syndrome (GBS) and metabolites.

Methods

Employing a two-sample Mendelian randomization (MR) approach, the study investigated the causal associations between 731 immune cell traits, 1400 metabolite levels and GBS leveraging summary-level data from a genome-wide association study (GWAS). To ensure the reliability of our findings, we further assessed horizontal pleiotropy and heterogeneity and evaluated the stability of MR results using the Leave-one-out method.

Results

This study revealed a causal relationship between CD3 on activated & secreting Tregs and GBS. Higher CD3 on activated and secreting Regulatory Tregs increased the risk of GBS (primary MR analysis odds ratio (OR) 1.31/SD increase, 95% confidence interval (CI) 1.08-1.58, p = 0.005). There was no reverse causality for GBS on CD3 on activated & secreting Tregs (p = 0.36). Plasma metabolite N-Acetyl-L-Alanine (ALA) was significantly positively correlated with GBS by using the IVW method (OR = 2.04, 95% CI, 1.26-3.30; p = 0.00038). CD3 on activated & secreting Tregs was found to be positively associated with ALA risk (IVW method, OR, 1.04; [95% CI, 1.01-1.07], p = 0.0078). Mediation MR analysis indicated the mediated proportion of CD3 on activated & secreting Tregs mediated by ALA was 10% (95%CI 2.63%, 17.4%).

Conclusion

In conclusion, our study identified a causal relationship between the level of CD3 on activated & secreting Tregs and GBS by genetic means, with a considerable proportion of the effect mediated by ALA. In clinical practice, thus providing guidance for future clinical research.

The role of inflammatory proteins in regulating the impact of lipid specifications on deep venous thrombosis: a two sample and mediated Mendelian randomization study

Objective

To investigate the potential mediating role of inflammatory proteins in the association between lipid species and Deep Venous Thrombosis (DVT).

Methods

A comprehensive analysis was conducted using pooled data from genome-wide association studies (GWAS), incorporating double-sample and reverse Mendelian randomization (MR) techniques, to identify the specific inflammatory proteins that act as intermediaries among 91 screened proteins in relation to deep vein thrombosis (DVT). Furthermore, a two-step MR approach was employed to quantify the proportion of DVT risk attributed to lipid effects mediated by these inflammatory proteins.

Results

The MR Analysis revealed that the two inflammatory proteins, as predicted by genetics, served as mediating factors in the impact of five lipids on DVT. No reverse effect of DVT was observed on 179 lipid species and 91 inflammatory proteins. In the case of TAG(58:7) and its influence on DVT, CCL20 played an intermediary role with an estimated proportion of 12.51% (ranging from 12% to 13%). SIRT2 exhibited a masking effect on DVT for PC(17:0/20:4) and PC(18:0/20:4), while CCL20 masked the impact of DVT on PC(14:0/18:2), PC(15:0/18:2), and PC(18:0/20:5).

Conclusions

In our study, we identified CCL20 as a crucial mediator in the association between TAG(58:7) and DVT, with a mediating proportion of 12.51% (12%-13%). Further investigations are warranted to explore other potential risk factors acting as mediators.

Genetic prediction of blood metabolites mediating the relationship between gut microbiota and Alzheimer's disease: a Mendelian randomization study

Background

Observational studies have suggested an association between gut microbiota and Alzheimer's disease (AD); however, the causal relationship remains unclear, and the role of blood metabolites in this association remains elusive.

Purpose

To elucidate the causal relationship between gut microbiota and AD and to investigate whether blood metabolites serve as potential mediators.

Materials and methods

Univariable Mendelian randomization (UVMR) analysis was employed to assess the causal relationship between gut microbiota and AD, while multivariable MR (MVMR) was utilized to mitigate confounding factors. Subsequently, a two-step mediation MR approach was employed to explore the role of blood metabolites as potential mediators. We primarily utilized the inverse variance-weighted method to evaluate the causal relationship between exposure and outcome, and sensitivity analyses including Contamination mixture, Maximum-likelihood, Debiased inverse-variance weighted, MR-Egger, Bayesian Weighted Mendelian randomization, and MR pleiotropy residual sum and outlier were conducted to address pleiotropy.

Results

After adjustment for reverse causality and MVMR correction, class Actinobacteria (OR: 1.03, 95% CI: 1.01-1.06, p = 0.006), family Lactobacillaceae (OR: 1.03, 95% CI: 1.00-1.05, p = 0.017), genus Lachnoclostridium (OR: 1.03, 95% CI: 1.00-1.06, p = 0.019), genus Ruminiclostridium9 (OR: 0.97, 95% CI: 0.94-1.00, p = 0.027) and genus Ruminiclostridium6 (OR: 1.03, 95% CI: 1.01-1.05, p = 0.009) exhibited causal effects on AD. Moreover, 1-ribosyl-imidazoleacetate levels (-6.62%), Metabolonic lactone sulfate levels (2.90%), and Nonadecanoate (19:0) levels (-12.17%) mediated the total genetic predictive effects of class Actinobacteria on AD risk. Similarly, 2-stearoyl-GPE (18:0) levels (-9.87%), Octadecanedioylcarnitine (C18-DC) levels (4.44%), 1-(1-enyl-stearoyl)-2-oleoyl-GPE (p-18:0/18:1) levels (38.66%), and X-23639 levels (13.28%) respectively mediated the total genetic predictive effects of family Lactobacillaceae on AD risk. Furthermore, Hexadecanedioate (C16-DC) levels (5.45%) mediated the total genetic predictive effects of genus Ruminiclostridium 6 on AD risk; Indole-3-carboxylate levels (13.91%), X-13431 levels (7.08%), Alpha-ketoglutarate to succinate ratio (-13.91%), 3-phosphoglycerate to glycerate ratio (15.27%), and Succinate to proline ratio (-14.64%) respectively mediated the total genetic predictive effects of genus Ruminiclostridium 9 on AD risk.

Conclusion

Our mediation MR analysis provides genetic evidence suggesting the potential mediating role of blood metabolites in the causal relationship between gut microbiota and AD. Further large-scale randomized controlled trials are warranted to validate the role of blood metabolites in the specific mechanisms by which gut microbiota influence AD.

Genetically predicted metabolites mediate the association between immune cells and metabolic dysfunction-associated steatotic liver disease: a mendelian randomization study

BACKGROUND

Existing studies have presented limited and disparate findings on the nexus between immune cells, plasma metabolites, and metabolic dysfunction-associated steatotic liver disease (MASLD). The aim of this study was to investigate the causal relationship between immune cells and MASLD. Additionally, we aimed to identify and quantify the potential mediating role of metabolites.

METHODS

A Mendelian randomization (MR) analysis was conducted using two samples of pooled data from genome-wide association studies on MASLD that included 2568 patients and 409,613 control individuals. Additionally, a mediated MR study was employed to quantify the metabolite-mediated immune cell effects on MASLD.

RESULTS

In this study, eight immunophenotypes were linked to the risk of MASLD, and thirty-five metabolites/metabolite ratios were linked to the occurrence of MASLD. Furthermore, a total of six combinations of immunophenotypic and metabolic factors demonstrated effects on the occurrence of MASLD, although the mediating effects of metabolites were not significant.

CONCLUSION

Our study demonstrated that certain immunophenotypes and metabolite/metabolite ratios have independent causal relationships with MASLD. Furthermore, we identified specific metabolites/metabolite ratios that are associated with an increased risk of MASLD. However, their mediating role in the causal association between immunophenotypes and MASLD was not significant. It is important to consider immune and metabolic disorders among patients with MASLD in clinical practice.

Genetic information supports a causal relationship between trace elements, inflammatory proteins, and COPD: evidence from a Mendelian randomization analysis

Objective

Dietary factors and nutritional status may be among the risk factors for Chronic Obstructive Pulmonary Disease (COPD). There exists a certain correlation between trace elements and COPD. Through Mendelian Randomization (MR) analysis, we investigated the causal relationships between trace elements, inflammatory proteins, and COPD.

Methods

We employed MR, multivariable MR (MVMR), and two-step MR (TSMR) approaches to assess the causal links between 15 trace elements and COPD, with 91 inflammatory proteins serving as mediators to further elucidate the tripartite causal relationships.

Results

Trace elements such as Folate (OR = 1.293, 95%CI 1.027-1.628; p = 0.029), Vitamin D (OR = 1.331, 95%CI 1.071-1.654; p = 0.010), Vitamin B12 (OR = 1.424, 95%CI 1.108-1.828; p = 0.006), and Iron (OR = 0.741, 95%CI 0.580-0.946; p = 0.016) demonstrated causal relationships with COPD. No causal relationship was observed in reverse MR. After adjusting for BMI, Folate (OR = 1.633, 95%CI 1.098-2.429; p = 0.015), Iron (OR = 0.507, 95%CI 0.31-0.778; p = 0.001), and Vitamin D (OR = 1.511, 95%CI 1.029-2.217; p = 0.034) were identified as independent risk factors for COPD, whereas Vitamin B12 (OR = 1.118, 95%CI 0.751-1.666; p = 0.581) was not. Mediation analysis indicated that CDCP1 (5.76%) may play a mediating role between Iron and COPD.

Conclusion

Trace elements such as Folate, Vitamin D, Vitamin B12, and Iron have causal relationships with COPD. After BMI adjustment, Folate, Vitamin D, and Iron emerge as independent risk factors. Furthermore, the inflammatory protein CDCP1 may partially mediate the causal relationship between Iron and COPD, offering a scientific basis for dietary recommendations that could benefit COPD patients. The supplementation of trace elements may be advantageous for individuals suffering from COPD.

Integrating plasma protein-centric multi-omics to identify potential therapeutic targets for pancreatic cancer

BACKGROUND

Deciphering the role of plasma proteins in pancreatic cancer (PC) susceptibility can aid in identifying novel targets for diagnosis and treatment.

METHODS

We examined the relationship between genetically determined levels of plasma proteins and PC through a systemic proteome-wide Mendelian randomization (MR) analysis utilizing cis-pQTLs from multiple centers. Rigorous sensitivity analyses, colocalization, reverse MR, replications with varying instrumental variable selections and additional datasets, as well as subsequent meta-analysis, were utilized to confirm the robustness of significant findings. The causative effect of corresponding protein-coding genes' expression and their expression pattern in single-cell types were then investigated. Enrichment analysis, between-protein interaction and causation, knock-out mice models, and mediation analysis with established PC risk factors were applied to indicate the pathogenetic pathways. These candidate targets were ultimately prioritized upon druggability and potential side effects predicted by a phenome-wide MR.

RESULTS

Twenty-one PC-related circulating proteins were identified in the exploratory phase with no evidence for horizontal pleiotropy or reverse causation. Of these, 11 were confirmed in a meta-analysis integrating external validations. The causality at a transcription level was repeated for neutrophil elastase, hydroxyacylglutathione hydrolase, lipase member N, protein disulfide-isomerase A5, xyloside xylosyltransferase 1. The carbohydrate sulfotransferase 11 and histo-blood group ABO system transferase exhibited high-support genetic colocalization evidence and were found to affect PC carcinogenesis partially through modulating body mass index and type 2 diabetes, respectively. Approved drugs have been established for eight candidate targets, which could potentially be repurposed for PC therapies. The phenome-wide investigation revealed 12 proteins associated with 51 non-PC traits, and interference on protein disulfide-isomerase A5 and cystatin-D would increase the risk of other malignancies.

CONCLUSIONS

By employing comprehensive methodologies, this study demonstrated a genetic predisposition linking 21 circulating proteins to PC risk. Our findings shed new light on the PC etiology and highlighted potential targets as priorities for future efforts in early diagnosis and therapeutic strategies of PC.

Genetically identified mediators associated with increased risk of stroke and cardiovascular disease in individuals with autism spectrum disorder

Growing evidence suggested that individuals with autism spectrum disorder (ASD) associated with stroke and cardiovascular disease (CVD). However, the causal association between ASD and the risk of stroke and CVD remains unclear. To validate this, we performed two-sample Mendelian randomization (MR) and two-step mediation MR analyses, using relevant genetic variants sourced from the largest genome-wide association studies (GWASs). Two-sample MR evidence indicated causal relationships between ASD and any stroke (OR = 1.1184, 95% CI: 1.0302-1.2142, P < 0.01), ischemic stroke (IS) (OR = 1.1157, 95% CI: 1.0237-1.2160, P = 0.01), large-artery atherosclerotic stroke (LAS) (OR = 1.2902, 95% CI: 1.0395-1.6013, P = 0.02), atrial fibrillation (AF) (OR = 1.0820, 95% CI: 1.0019-1.1684, P = 0.04), and heart failure (HF) (OR = 1.1018, 95% CI: 1.0007-1.2132, P = 0.05). Additionally, two-step mediation MR suggested that type 2 diabetes mellitus (T2DM) partially mediated this effect (OR = 1.14, 95%CI: 1.02-1.28, P = 0.03). The mediated proportion were 10.96% (95% CI: 0.58%-12.10%) for any stroke, 11.77% (95% CI: 10.58%-12.97%) for IS, 10.62% (95% CI: 8.04%-13.20%) for LAS, and 7.57% (95% CI: 6.79%-8.36%) for HF. However, no mediated effect was observed between ASD and AF risk. These findings have implications for the development of prevention strategies and interventions for stroke and CVD in patients with ASD.

Dissecting causal relationships between immune cells, plasma metabolites, and COPD: a mediating Mendelian randomization study

Objective

This study employed Mendelian Randomization (MR) to investigate the causal relationships among immune cells, COPD, and potential metabolic mediators.

Methods

Utilizing summary data from genome-wide association studies, we analyzed 731 immune cell phenotypes, 1,400 plasma metabolites, and COPD. Bidirectional MR analysis was conducted to explore the causal links between immune cells and COPD, complemented by two-step mediation analysis and multivariable MR to identify potential mediating metabolites.

Results

Causal relationships were identified between 41 immune cell phenotypes and COPD, with 6 exhibiting reverse causality. Additionally, 21 metabolites were causally related to COPD. Through two-step MR and multivariable MR analyses, 8 cell phenotypes were found to have causal relationships with COPD mediated by 8 plasma metabolites (including one unidentified), with 1-methylnicotinamide levels showing the highest mediation proportion at 26.4%.

Conclusion

We have identified causal relationships between 8 immune cell phenotypes and COPD, mediated by 8 metabolites. These findings contribute to the screening of individuals at high risk for COPD and offer insights into early prevention and the precocious diagnosis of Pre-COPD.

Genetic Association between Lipid-Regulating Drug Targets and Diabetic Retinopathy: A Drug Target Mendelian Randomization Study

Background

Diabetic retinopathy (DR) is a diabetic microvascular complication and a leading cause of vision loss. However, there is a lack of effective strategies to reduce the risk of DR currently. The present study is aimed at assessing the causal effect of lipid-regulating targets on DR risk using a two-sample Mendelian randomization (MR) study.

Method

Genetic variants within or near drug target genes, including eight lipid-regulating targets for LDL-C (HMGCR, PCSK9, and NPC1L1), HDL-C (CETP, SCARB1, and PPARG), and TG (PPARA and LPL), were selected as exposures. The exposure data were obtained from the IEU OpenGWAS project. The outcome dataset related to DR was obtained from the FinnGen research project. Inverse-variance-weighted MR (IVW-MR) was used to calculate the effect estimates by each target. Sensitivity analyses were performed to verify the robustness of the results.

Results

There was suggestive evidence that PCSK9-mediated LDL-C levels were positively associated with DR, with OR (95% CI) of 1.34 (1.02-1.77). No significant association was found between the expression of HMGCR- and NPC1L1-mediated LDL-C levels; CETP-, SCARB1-, and PPARG-mediated HDL-C levels; PPARA- and LPL-mediated TG levels; and DR risk.

Conclusions

This is the first study to reveal a genetically causal relationship between lipid-regulating drug targets and DR risk. PCSK9-mediated LDL-C levels maybe positively associated with DR risk at the genetic level. This study provides suggestive evidence that PCSK9 inhibition may reduce the risk of DR.

Genetically predicted blood metabolites mediate the association between circulating immune cells and pancreatic cancer: A Mendelian randomization study

BACKGROUND

Pancreatic cancer is characterized by metabolic dysregulation and unique immunological profiles. Nevertheless, the comprehensive understanding of immune and metabolic dysregulation of pancreatic cancer remains unclear. In the present study, we aimed to investigate the causal relationship of circulating immune cells and pancreatic cancer and identify the blood metabolites as potential mediators.

METHODS

The exposure and outcome genome-wide association studies (GWAS) data used in the present study were obtained from the GWAS open-access database (https://gwas.mrcieu.ac.uk). The study used 731 circulating immune cell features, 1400 types of blood metabolites and pancreatic cancer from GWAS. We then performed bidirectional Mendelian randomization (MR) analyses to explore the causal relationships between the circulating immune cells and pancreatic cancer, and two-step MR to discover potential mediating blood metabolites in this process. All statistical analyses were performed in R software. The STROBE-MR (i.e. Strengthening the Reporting of Observational Studies in Epidemiology using Mendelian Randomization) checklist for the reporting of MR studies was also used.

RESULTS

MR analysis identified seven types of circulating immune cells causally associated with pancreatic cancer. Furthermore, there was no strong evidence that genetically predicted pancreatic cancer had an effect on these seven types of circulating immune cells. Further two-step MR analysis found 10 types of blood metabolites were causally associated with pancreatic cancer and the associations between circulating CD39+CD8+ T cells and pancreatic cancer were mediated by blood orotates with proportions of 5.18% (p = 0.016).

CONCLUSIONS

The present study provides evidence supporting the causal relationships between various circulating immune cells, especially CD39+CD8+ T cells, and pancreatic cancer, with a potential effect mediated by blood orotates. Further research is needed on additional risk factors as potential mediators and establish a comprehensive immunity-metabolism network in pancreatic cancer.

Relationships among gut microbiota, plasma metabolites, and juvenile idiopathic arthritis: a mediation Mendelian randomization study

Objective

The objective of this study is to investigate the causal relationship between gut microbiota and juvenile idiopathic arthritis, and to identify and quantify the potential role of plasma metabolites as mediators.

Methods

Using summary-level data from genome-wide association studies, a two-sample Mendelian randomization was conducted involving 131 gut microbiota genus, 1,400 plasma metabolites, and juvenile idiopathic arthritis. Additionally, a two-step approach was employed to quantify the proportion of the effect of gut microbiota on juvenile idiopathic arthritis mediated by plasma metabolites. Effect estimation primarily utilized Inverse Variance Weighting, with further validation using Bayesian weighted Mendelian randomization.

Results

In our MR analysis, a positive correlation was observed between Rikenellaceae and the risk of juvenile idiopathic arthritis, while Dorea showed a negative correlation with juvenile idiopathic arthritis risk. Mediation analysis indicated that Furaneol sulfate levels acted as a mediator between Dorea and juvenile idiopathic arthritis, with an indirect effect proportion of 19.94, 95% CI [8.86-31.03%].

Conclusion

Our study confirms a causal relationship between specific microbial genus and juvenile idiopathic arthritis, and computes the proportion of the effect mediated by plasma metabolites, offering novel insights for clinical interventions in juvenile idiopathic arthritis.

Abnormal brain structure in atopic dermatitis: Evidence from Mendelian randomization study

BACKGROUND

Structural abnormalities in the brain of patients with atopic dermatitis (AD) have been reported; however, the cause has not been determined yet. Herein, we used Mendelian randomization (MR) to reveal the causal effect of AD on brain structure.

METHODS

This study utilized summary statistics from genome-wide association studies (GWASs) to investigate a collection of cerebral structural measures, encompassing cortical thickness (CT), cortical surface area (CA), and subcortical volumes in T1 images. A comprehensive GWAS meta-analysis identified a total of 20 independent single nucleotide polymorphisms linked to AD, surpassing the genome-wide significance threshold (p < 5 × 10⁻⁸). MR estimates were aggregated through the application of the inverse variance weighted method. Additional complementary analyses (i.e., MR-Egger and weighted median approaches) were conducted to further assess the robustness of the obtained results. Sensitivity analysis and multivariate MR (MVMR) while adjusting for brain structural changes risk factors (i.e., depression and anxiety) were performed to assess the reliability and stability of observed causality.

RESULTS

Genetically determined AD exhibited a causal link with reduced caudate volumes (IVW-MR: β = -0.186, p = 0.001, p-corrected = 0.009). Furthermore, we identified potential causal associations between AD and reduced CT in the cingulate region (posterior cingulate, IVW-MR: β = -0.065, p = 0.018, p-corrected = 0.551; isthmus cingulate, IVW-MR: β = -0.086, p = 0.003, p-corrected = 0.188), as well as abnormal cortical surface area (CA) in the supramarginal (IVW-MR: β = -0.047, p = 0.044, p-corrected = 0.714) and isthmus cingulate (IVW-MR: β = 0.053, p = 0.018, p-corrected = 0.714). Additional supplementary analyses yielded consistent outcomes. There was no evidence of horizontal pleiotropy. MVMR analysis showed that the causal effects of AD on abnormal brain structure remained significant while adjusting for depression and anxiety.

CONCLUSION

This MR study provided suggestive evidence that decreased caudate nucleus, posterior cingulate cortex, isthmus cingulate cortex and supramarginal gyrus are suggestively associated with higher AD risk. Future investigation into the brain regions is recommended, which helps to clarify the underlying mechanisms and point to new therapies against AD.