General anesthesia induces acute cell-free DNA methylation changes in peripheral blood

Short-term and long-term adverse events could occur after general anesthesia (GA) and the specific mechanism driving these effects has not yet been well-characterized. In this study, we aimed to evaluate the global effect of GA on DNA methylation in the cell-free DNA (cfDNA) of surgical lung-nodule patients.

This large retrospective cohort study enrolled 1,006 surgical lung nodule patients (529 pre-anesthesia, and 477 post-anesthesia). Methylation profiles of the cfDNA isolated from plasma were analyzed by targeted bisulfite sequencing using an enrichment panel covering 12,899 biologically informative methylation regions and 105,844 CpG sites.

By comparing the pre-anesthesia to the post-anesthesia group, a total of 4,562 differentially methylated regions (DMRs) were identified as GA-induced DMRs. Pathway enrichment analysis annotated with cellular processes including pattern specification process, head/heart/bone/tissues development and morphogenesis pathways, cell-adhesion, extra-cellular matrix (ECM) remodeling pathways, and signaling pathways including PI3K-AKT pathway, Ca²⁺ dependent pathway and RAS/extracellular signal-regulated kinase (RAS/ERK) signaling pathway. Prediction models using 20 DMR markers were derived using Random Forest, which could accurately predict biochemical indicators for post-operative abnormal coagulation function including activated-partial-thromboplastin-time [APTT, area under curve (AUC) 0.81], international normalized ratio (INR, AUC 0.87), D-dimer (AUC 0.82), neutrophil (AUC 0.84) and monocyte (AUC 0.79). Low methylation level in one of the top DMR markers, cg02032606 (DLX-4 gene), was found to be associated with worse overall survival in both lung adenocarcinoma and squamous carcinoma patients.

This study demonstrated that GA could result in acute DNA methylation changes, which were associated with tissue damage and repair responses. These GA-induced methylation changes were associated with postoperative coagulation functions and could serve as a promising predictive biomarker for coagulation disorders after surgery.