Causal relationship between immune cells, inflammatory cytokines, metabolites, and erectile dysfunction: a two-sample...

Area of Science:

• Genetics
• Immunology
• Metabolomics
• Epidemiology

Background:

• Previous research explored links between immune inflammation, metabolism, and erectile dysfunction (ED), but causality remained unestablished due to limitations like biases and confounding factors.
• A two-sample Mendelian randomization (MR) approach was employed to overcome these limitations and investigate causal relationships.

Purpose of the Study:

• To elucidate the causal relationships between immune cell phenotypes, inflammatory cytokines, plasma metabolites, and the risk of developing ED.
• To identify specific immune and metabolic factors that causally influence ED risk.

Main Methods:

• Utilized large-scale genome-wide association studies (GWAS) data for exposures including 91 inflammatory cytokines, 731 immune phenotypes, and 1,400 circulating metabolites.
• Employed a two-sample Mendelian randomization (MR) analysis with the inverse variance weighted (IVW) method as the primary approach, using ED data from the IEU Open GWAS database (n=223,805) as the outcome.
• Performed sensitivity analyses (Cochran's Q test, MR-Egger intercept) to ensure the robustness of results against heterogeneity and horizontal pleiotropy.

Main Results:

• Identified 12 factors significantly associated with ED risk (P<0.01), including five immune cell types, one inflammatory cytokine, and two metabolites.
• Specific immune cell markers (e.g., CD19 on B cells, CD4 on T cells) and metabolites (e.g., glycerol) showed significant associations with ED.
• Elevated urokinase-type plasminogen activator (uPA) levels were found to reduce ED risk, while certain metabolite ratios also demonstrated significant associations.

Conclusions:

• The MR analysis confirms that immune inflammation and metabolic factors exert both inducing and protective effects on ED risk.
• Findings provide novel insights into the pathogenesis of ED and offer valuable information for clinicians in managing and preventing the condition.
• This study contributes to a deeper understanding of the complex interplay between immunity, metabolism, and ED.