Abstract Body (Do not enter title and authors here): Background: Clonal hematopoiesis of indeterminate potential (CHIP) has been associated with an increased incidence of common late-onset diseases including myocardial infarction.
Research Question: Here we examined the impact of CHIP on mortality in patients with coronary artery disease (CAD) and further explored potential underlying mechanisms.
Methods: CAD patients were examined for CHIP-defining mutations using deep DNA sequencing. Propensity score matching was used to compare CHIP CAD with non-CHIP CAD patients. Survival was analyzed using Kaplan-Meier curves and Cox proportional hazard models. Functional aspects were investigated at the protein and RNA level in cardiovascular relevant human postmortem tissue from the Munich cardIovaScular StudIes biObaNk (MISSION), in CAD patients from an independent cohort and in in-vitro macrophage models.
Results: Within 7,933 CAD patients screened by deep-DNA-sequencing with a 13 gene panel, 2,002 carried at least one CHIP defining mutation with a variant allele frequency ≥2%. After 1:1 matching with non-CHIP carriers we revealed a significantly elevated 3-year mortality in the group of CHIP carriers [HR 1.48 (CI 95% 1.23-1.78); p<0.0001)] as well as in carriers of mutations in one out of seven individual genes – ASXL1, DNMT3A, PPM1D, SF3B1, SRSF2, TET2, and U2AF1. In human coronary atherosclerotic plaque we visualized CHIP-mutations within leukocytes. Further, within coronary artery plaque of deceased TET2 mutation carriers (n=26 vs. n=13 controls) we identified by proteomic profiling an upregulation of inflammatory and metabolic pathways, including enhanced lipid metabolism. In an independent cohort of CAD patients undergoing coronary bypass surgery, RNA sequencing data from monocyte-derived macrophages revealed in TET2 CHIP carriers associations with CAD complexity. TET2-mutated macrophages studied in-vitro revealed an increased uptake of low-density lipoprotein (LDL) and oxidized LDL-cholesterol besides a known upregulation of inflammatory pathways.
Conclusion: In summary, this study emphasizes CHIP as a significant prognostic factor in CAD patients, associated with increased complexity of CAD and altered gene expression within human coronary artery plaques. Mechanistically, TET2 mutations modify the behavior of CHIP-affected macrophages, leading to heightened inflammation and increased uptake of LDL-cholesterol.