Integrating clinical data and genetic susceptibility to elucidate the relationship between systemic lupus erythematosus and human cytomegalovirus infection

BACKGROUND

Viral infections are known to induce the occurrence and pathogenesis of systemic lupus erythematosus (SLE). Previous studies have indicated a possible relationship between SLE and human cytomegalovirus (HCMV) infection and have attributed HCMV to be associated with various autoantibodies; however, these studies were constrained by variations in sample size and potential selection bias. Therefore, in the present study, we aimed to elucidate the relationship between HCMV and autoantibodies in patients with SLE by integrating clinical data and genetic susceptibility.

METHODS

Using various statistical methods, we conducted a retrospective analysis of the spectrum of SLE autoantibodies and HCMV infections among patients hospitalized at our center over the past 10 years. Machine learning modeling was used to predict active HCMV infections based on the antinuclear (ANA) spectrum. Moreover, Mendelian randomization (MR) was used to investigate the causal relationship between SLE and HCMV infection.

RESULTS

In the HCMV group, the levels of ANA, anti-dsDNA, anti-histone antibody (AHA), and anti-nucleosome antibody (ANuA) were significantly increased (P < 0.001) and were linked to the presence of CMV-pp65-antigen-positive polymorphonuclear leukocytes (P < 0.001). A weak correlation was observed between the titers of anti-CMV IgM and ANA (P < 0.001). The ANA spectrum demonstrated a strong predictive performance for active HCMV infection based on principal component analysis (Adonis and ANOSIM P < 0.001) as well as support vector machine and extreme gradient boosting modeling. MR analyses of inverse-variance weighted, weighted mean, MR-Egger, and weighted mode revealed that patients with SLE were at a higher risk of developing HCMV infection (P < 0.05). However, HCMV infection did not have a causal effect on SLE (P > 0.05).

CONCLUSION

The ANA spectrum in patients with SLE can be used to predict HCMV infection status. Due to the inherent susceptibility of patients with SLE to HCMV infection, we propose for the first time that if a patient with SLE exhibits high serum titers of ANA, anti-dsDNA, ANuA, and AHA, caution should be exercised for HCMV infection, which can contribute to the clinical assessment of SLE and improve patient prognosis.

The lack of causal link between myopia and intraocular pressure: Insights from cross-sectional analysis and Mendelian randomization study

OBJECTIVE

This study aimed to explore the potential causal relationship between intraocular pressure (IOP) and myopia.

METHODS

The study included 3,459 patients who underwent corneal refractive surgery at our institution between 2021 and 2023. Preoperative data on IOP, spherical equivalent (SE), axial length (AL), and corneal thickness (CCT) were collected. The association between IOP and myopia was investigated through rank correlation analysis, and causal inference was examined using Mendelian randomization (MR) methods, including MR-Egger, weighted median, mode-based estimation, simple mode, and inverse variance weighted (IVW) approaches. Utilizing summary statistics from genome-wide association studies (GWAS), IOP was considered as the exposure, with myopia as the outcome variable. IVW method was employed for the primary analysis, supplemented by sensitivity analyses.

RESULTS

Cross-sectional analysis revealed a non-significant association between corrected IOP (cIOP) and myopia (r = -0.019, P = 0.12). MR analysis indicated a non-significant genetic causal relationship between cIOP and myopia under the IVW method (OR = 1.001; 95 % CI [0.999-1.003], P = 0.22), a finding corroborated in replication samples (OR = 0.98; 95 % CI [0.96-1.00], P = 0.099).

CONCLUSION

This study did not find a direct causal link between IOP and the development of myopia. These findings challenge the traditional role attributed to IOP in the progression of myopia and highlight the complex, multifactorial process of myopia development. This provides a new perspective on understanding the intricate mechanisms behind myopia progression.

The human cerebral cortex morphology in neuropsychiatric disorders: A causal inference based on Mendelian Randomization

BACKGROUND

Neuropsychiatric disorders, including Alzheimer's disease (AD), major depressive disorder (MDD), anxiety disorders, attention-deficit/hyperactivity disorder (ADHD), bipolar disorder, insomnia, and schizophrenia (SCZ), are prevalent and impose substantial morbidity and mortality worldwide. Brain morphometry, is increasingly recognized for its relevance to cognitive, emotional, and behavioral functions, yet its causal links to neuropsychiatric pathologies are not well established.

OBJECTIVE

This study aimed to explore the causal relationships between cortical thickness (TH) and surface area (SA) with 7 neuropsychiatric disorders using Mendelian randomization (MR) analyses.

METHODS

We employed data from genome-wide association studies (GWAS) comprising 51,665 individuals to evaluate cortical SA and TH. We selected single nucleotide polymorphisms (SNPs) as instrumental variables for MR analyses to investigate the causal associations with neuropsychiatric disorders.

RESULTS

Increased TH in the paracentral cortex was associated with a reduced risk of ADHD. Similarly, a thicker temporal pole was linked to a lower risk of MDD. The TH of the lingual region showed an inverse association with anxiety disorders. The SA of the fusiform gyrus was associated with AD risk, and morphological variations in the caudal middle frontal cortex, isthmus cingulate cortex, and temporal pole were correlated with bipolar disorder risk. An increased TH of the posterior cingulate cortex was associated with higher insomnia risk, and the TH of the pericalcarine region negatively correlated with SCZ risk.

CONCLUSION

This research provided novel evidence for the causal role of cerebral cortex morphology in neuropsychiatric disorders, suggesting potential targets for therapeutic intervention.

Genetic causal association between frozen shoulder and carpal tunnel syndrome: a two-sample mendelian randomization

OBJECTIVE

Observational studies have suggested an association between frozen shoulder (FS) and carpal tunnel syndrome (CTS). However, due to challenges in establishing a temporal sequence, the causal relationship between these two conditions remains elusive. This study, based on aggregated data from large-scale population-wide genome-wide association studies (GWAS), investigates the genetic causality between FS and CTS.

METHODS

Initially, a series of quality control measures were employed to select single nucleotide polymorphisms (SNPs) closely associated with the exposure factors. Two-sample Mendelian randomization (MR) was utilized to examine the genetic causality between FS and CTS, employing methods including Inverse-Variance Weighted (IVW), MR-Egger, Weighted Median, Simple Mode, and Weighted Mode approaches. Subsequently, sensitivity analyses were conducted to assess the robustness of the MR analysis results.

RESULTS

IVW analysis results indicate a positive causal relationship between CTS and FS (p < 0.05, OR > 1), while a negative causal relationship between the two conditions was not observed. Heterogeneity tests suggest minimal heterogeneity in our IVW analysis results (p > 0.05). Multivariable MR testing also indicates no pleiotropy in our IVW analysis (p > 0.05), and stepwise exclusion tests demonstrate the reliability and stability of the MR analysis results. Gene Ontology (GO) pathway analysis reveals enrichment of genes regulated by the associated SNPs in the TGFβ-related pathways.

CONCLUSION

This study provides evidence of the genetic causal association between frozen shoulder and carpal tunnel syndrome and provides new insights into the genetics of fibrotic disorders.

Investigating the association between serum ADAM/ADAMTS levels and bone mineral density by mendelian randomization study

PURPOSE

A Disintegrin and Metalloproteinase (ADAM) and A Disintegrin and Metalloproteinase with Thrombospondin Motif (ADAMTS) have been reported potentially involved in bone metabolism and related to bone mineral density. This Mendelian Randomization (MR) analysis was performed to determine whether there are causal associations of serum ADAM/ADAMTS with BMD in rid of confounders.

METHODS

The genome-wide summary statistics of four site-specific BMD measurements were obtained from studies in individuals of European ancestry, including forearm (n = 8,143), femoral neck (n = 32,735), lumbar spine (n = 28,498) and heel (n = 426,824). The genetic instrumental variables for circulating levels of ADAM12, ADAM19, ADAM23, ADAMTS5 and ADAMTS6 were retrieved from the latest genome-wide association study of European ancestry (n = 5336 ~ 5367). The estimated causal effect was given by the Wald ratio for each variant, the inverse-variance weighted model was used as the primary approach to combine estimates from multiple instruments, and sensitivity analyses were conducted to assess the robustness of MR results. The Bonferroni-corrected significance was set at P < 0.0025 to account for multiple testing, and a lenient threshold P < 0.05 was considered to suggest a causal relationship.

RESULTS

The causal effects of genetically predicted serum ADAM/ADAMTS levels on BMD measurements at forearm, femoral neck and lumbar spine were not statistically supported by MR analyses. Although causal effect of ADAMTS5 on heel BMD given by the primary MR analysis (β = -0.006, -0.010 to 0.002, P = 0.004) failed to reach Bonferroni-corrected significance, additional MR approaches and sensitivity analyses indicated a robust causal relationship.

CONCLUSION

Our study provided suggestive evidence for the causal effect of higher serum levels of ADAMTS5 on decreased heel BMD, while there was no supportive evidence for the associations of ADAM12, ADAM19, ADAM23, and ADAMTS6 with BMD at forearm, femoral neck and lumbar spine in Europeans.

Genetic relationship between rheumatoid arthritis and cardiovascular diseases : A systematic review of Mendelian randomization studies

OBJECTIVE

Rheumatoid arthritis (RA) is recognized as a chronic autoimmune disorder with systemic inflammation and joint damage. Its potential role as a risk factor for cardiovascular diseases (CVD) is increasingly noted. This review delves into the causal relationship between RA and CVD, with Mendelian randomization (MR) offering a genetic perspective.

METHODS

An extensive search was conducted in PubMed, Cochrane and Web of Science to identify MR studies addressing the RA-CVD link. Out of 530 studies, 9 met the inclusion criteria, which were rigorously assessed using a critical appraisal checklist. These were further stratified by a sensitivity analysis into categories reflecting the strength of their evidence, from not evaluable to robust.

RESULTS

From the nine included studies, eight supported a causal association between RA and an increased risk of CVD, specifically coronary artery disease (CAD) and one did not support a link between RA and heart failure. The results suggest that genetic factors associated with RA may contribute to an elevated risk for CVD. Chronic inflammation, prevalent in RA, emerges as a key mediator in this connection.

CONCLUSION

The systematic review corroborates a genetic causal link between RA and CVD, as evidenced by eight of the nine MR studies reviewed. This suggests a need for integrated cardiovascular risk management in the treatment of RA patients. The findings advocate considering anti-inflammatory treatment that can reduce cardiovascular risk. The overarching evidence signifies a potential direction for new therapeutic strategies aimed at enhancing cardiovascular health in RA patients.

Exploring the genetic link between gastroesophageal reflux disease and pancreatic cancer: insights from Mendelian randomization

BACKGROUND

Gastroesophageal reflux disease (GERD) is increasingly recognized for its associations with extragastric diseases, yet its potential role in pancreatic cancer (PC) etiology remains underexplored. This study investigates the genetic causal relationship between GERD and PC using Mendelian randomization (MR), a method designed to reduce confounding factors.

METHODS

A two-sample MR analysis was conducted using genome-wide association studies (GWAS) data. The inverse variance weighted (IVW) method was applied, with additional sensitivity analyses performed to evaluate pleiotropy and heterogeneity.

RESULTS

The IVW analysis demonstrated a significant genetic association between the genetic signature predisposing to GERD and an increased risk of PC (OR: 1.36, 95% CI: 1.04-1.80, P = 0.03). There was no evidence of pleiotropy (P = 0.71) or heterogeneity (P = 0.94).

CONCLUSIONS

Our study provides robust genetic evidence supporting that the genetic predisposition to GERD is associated with an increased risk of PC. These findings emphasize the necessity of integrating GERD into PC risk assessments and encourage further research to elucidate the underlying biological mechanisms. This insight holds potential to inform strategies for early detection, prevention, and personalized management of PC in GERD patients.

Causal relationship between immune cells and telomere length: mendelian randomization analysis

BACKGROUND

The causal relationship between immune cells and telomere length remains controversial.

METHODS

Data on the immune cells were obtained from a previous study with 3,757 participants. Data on telomere length were obtained from the OpenGWAS database. Genome-Wide Association Study (GWAS) data were obtained and screened for eligible instrumental variables (IVs) using the TwoSampleMR package and the Phenoscanner database. To investigate the genetic causality between immune cells and telomere length, Mendelian randomization (MR) analysis and Bayesian weighted Mendelian randomization (BWMR) analysis were used.

RESULTS

MR analysis showed that there is indeed a genetic causal relationship between immune cells and telomere length. A total of 16 immune cells were successfully validated. A positive correlation was found between telomere length and immune cells such as CD28 + CD45RA + CD8br %CD8br (OR = 1.002, 95%CI: 1.000-1.003). A negative correlation was found between telomere length and immune cells such as Transitional AC (OR = 0.991, 95%CI: 0.984-0.997) (P < 0.05). Reverse MR analysis similarly confirmed that telomere length can affect four types of immune cells, including CD25 on IgD + CD24- (OR = 1.291, 95%CI: 1.060-1.571), at the genetic level.

CONCLUSION

There is indeed a mutual genetic causality between immune cells and telomere length, which will provide theoretical basis and support for more subsequent clinical studies.

Association between blood mitochondrial DNA copy number and mental disorders: A bidirectional two-sample mendelian randomization study

BACKGROUND

Mitochondria is essential for cellular energy production, oxidative stress, and apoptosis. Mitochondrial DNA (mtDNA) encodes essential proteins for mitochondrial function. Although several studies have explored the association between changes in mtDNA copy number (mtDNA-CN) and risk of mental disorders, the results remain debated. This study used a bidirectional two-sample Mendelian randomization (MR) analysis to examine the genetic causality between mtDNA-CN and mental disorders.

METHODS

Genome-wide association study (GWAS) data for mtDNA-CN were sourced from UK biobank, involving 383,476 European cases. GWAS data for seven mental disorders-attention deficit/hyperactivity disorder, autism spectrum disorder (ASD), schizophrenia, bipolar disorder, major depressive disorder, anxiety, and obsessive-compulsive disorder-were primarily obtained from the Psychiatric Genomics Consortium. Causal associations were assessed using inverse variance weighting, with sensitivity analyses via the weighted median and MR-Egger methods. Reverse MR considered the seven mental disorders as exposures. All analyses were replicated with additional mtDNA-CN GWAS data from 465,809 individuals in the Heart and Ageing Research in Genomic Epidemiology consortium and the UK Biobank.

RESULTS

Forward MR observed a 27 % decrease in the risk of ASD per standard deviation increase in genetically determined blood mtDNA-CN (OR = 0.73, 95%CI: 0.58-0.92, p = 0.002), with no causal effects on other disorders. Additionally, reverse MR did not indicate a causal association between any of the mental disorders and mtDNA-CN. Validation analyses corroborated these findings, indicating their robustness.

CONCLUSIONS

Our study supports the potential causal association between mtDNA-CN and the risk of ASD, suggesting that mtDNA-CN could serve as a promising biomarker for early screening of ASD.