Clonal hematopoiesis of indeterminate potential (CHIP) affects cardiovascular disease severity via pro-inflammatory myeloid cells without increased plaque-side accumulation

C. Ehlert (Freiburg im Breisgau)¹, T.-S. Dederichs (Freiburg im Breisgau)², A. Yerdenova (Freiburg im Breisgau)³, H. Horstmann (Freiburg im Breisgau)³, T. A. Vico (Freiburg im Breisgau)², S. Nübling (Freiburg im Breisgau)⁴, R. Peyronnet (Freiburg im Breisgau)⁴, H. Becker (Freiburg)⁵, D. Pfeifer (Freiburg)⁵, C. Niemöller (Freiburg)⁵, N. Anto-Michel (Graz)⁶, A. Zirlik (Graz)⁷, C. Bode (Freiburg im Breisgau)³, D. Wolf (Freiburg im Breisgau)¹, C. von zur Mühlen (Freiburg im Breisgau)⁸, K. Kaier (Freiburg im Breisgau)⁹, S. Preissl (Freiburg im Breisgau)¹⁰, T. Heidt (Bühl)¹¹, D. Westermann (Freiburg im Breisgau)¹², I. Hilgendorf (Freiburg im Breisgau)^1
1Universitäts-Herzzentrum Freiburg - Bad Krozingen Klinik für Kardiologie und Angiologie Freiburg im Breisgau, Deutschland; ²Universitäts-Herzzentrum Freiburg - Bad Krozingen Freiburg im Breisgau, Deutschland; ³Universitäts-Herzzentrum Freiburg - Bad Krozingen Klinik für Kardiologie und Angiologie I Freiburg im Breisgau, Deutschland; ⁴Universitäts-Herzzentrum Freiburg - Bad Krozingen Institut für Experimentelle Kardiovaskuläre Medizin Freiburg im Breisgau, Deutschland; ⁵Uniklinik Freiburg Klinik für Innere Medizin I Freiburg, Deutschland; ⁶LKH-Univ. Klinikum Graz - Universitätsklinik für Innere Medizin Experimentelle Kardiologie Graz, Österreich; ⁷LKH-Univ. Klinikum Graz - Universitätsklinik für Innere Medizin Klinische Abteilung für Kardiologie Graz, Österreich; ⁸Albert- Ludwigs-Universität Freiburg Innere Medizin III, Kardiologie und Angiologie Freiburg im Breisgau, Deutschland; ⁹Universitätsklinikum Freiburg Institut für Medizinische Biometrie und Statistik Freiburg im Breisgau, Deutschland; ¹⁰Universitätsklinikum Freiburg Institut für Pharmakologie Freiburg im Breisgau, Deutschland; ¹¹Max Grundig Klinik Kardiologie Bühl, Deutschland; ¹²Universitäts-Herzzentrum Freiburg - Bad Krozingen Innere Medizin III, Kardiologie und Angiologie Freiburg im Breisgau, Deutschland

Background

Clonal hematopoiesis of indeterminate potential (CHIP) is an age‑associated expansion of blood cells that carry leucemia-associated somatic mutations. CHIP mutations increase the risk of cardiovascular disease and are associated with cardiovascular driven increase of mortality. Our study aimed to understand the relevance of CHIP in patients of cardiovascular risk, how CHIP mutations affect myeloid cell biology and their impact on cardiovascular tissue.

Methods and Results

We conducted a prospective, observational study to screen CHIP-driver mutations in patients who were admitted for percutaneous coronary intervention. 815 patients admitted for left heart coronary angiography were screened. Of 178 included patients 30% (n=53) were identified as CHIP carriers. The prevalence of CHIP in our cohort was at least 2 times higher than that in general public. Gensini Score was used to quantify coronary artery disease severity, which was significantly worse in middle-aged (40-70 years) CHIP carriers than non-carriers. Within CHIP-carriers, the variant allel frequency (VAF) showed a strong performance as a distinguisher between coronary artery disease (CAD)- and non-CAD-patients (AUC 0.82 in middle aged patients).

We collected tissue and blood samples from CHIP-carriers undergoing carotid endarterectomy and heart surgery (n=9, n=4) to measure the accumulation of CHIP carrying myeloid cells in different tissues and to investigate their inflammatory profile. Droplet digital polymerase chain reaction (ddPCR) detected similar sizes of CHIP clones in circulating monocytes and tissue-bound macrophages even among CCR2– (resident) cardiac macrophages. Bulk RNA sequencing and GO-Term-Analysis revealed a pro-inflammatory phenotype of myeloid cells of CHIP-carriers compared to matched Non-carriers.

Conclusion

CHIP prevalence is at least doubled in CAD patients compared to the general public. Carrying a CHIP-mutation is associated with a higher disease severity in middle aged patients. In those middle aged CHIP carriers the VAF proves to be a strong predictor of CAD. When investigating cardiovascular (CV) tissue, mutated myeloid cells did not preferably accumulate in CV tissues but bulk RNA sequencing of tissue macrophages showed a significantly higher inflammation score in carriers than in their counterparts.