M Samak(1,2*§), L Klösener(1,2*), G Germena(1,2), D Lerm(3), J Li Ye(4), F Bleckwedel(5), A Moussavi(2,6,7), F Ramos Gomes(8), M Sitte(9), W Möbius(10), S Steffens(11,12), L Zelarayan(2,5), C Lenz(13), C Bär(4,14), R Behr(2,15), S Boretius(2,6), F Alves(8), T Thum(4,14,16), M Mietsch(1,2#), R Hinkel(1,2,17#)

1. Laboratory Animal Science Unit, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany; 2. German Center for Cardiovascular Research (DZHK), Partner Site Lower Saxony, Göttingen, Germany; 3. Medical Informatics, Friedrich-Alexander University (FAU), Erlangen-Nürnberg, Erlangen, Germany; 4. Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School, Hannover, Germany; 5. Institute of Pharmacology and Toxicology, University Medical Center Göttingen (UMG), Göttingen, Germany; 6. Functional Imaging Laboratory, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany; 7. Department of Electrical Engineering and Information Technology, South Westphalia University of Applied Sciences, Hagen, Germany; 8. Translational Molecular Imaging, Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany; 9. NGS - Integrative Genomics Core Unit (NIG), Institute of Pathology, University Medical Center Göttingen (UMG), Göttingen, Germany; 10. Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences - City Campus, Göttingen, Germany; 11. Institute of Cardiovascular Prevention, Ludwig-Maximilians-Universität München (LMU), Munich, Germany; 12. German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany; 13. Institute of Clinical Chemistry, University Medicine Göttingen, Georg-August-University, Robert-Koch-Straße 40, Göttingen, Germany; 14. Center for Translational Regenerative Medicine, Hannover Medical School, Hannover, Germany; 15. Platform Stem Cell Biology and Regeneration, German Primate Center, Leibniz Institute for Primate Research, Göttingen, Germany; 16. Fraunhofer Institute for Toxicology and Experimental Medicine ITEM, Hannover, Germany; 17. Institute of Animal Hygiene, Animal Welfare and Farm Animal Behavior, University of Veterinary Medicine, Hannover, Germany

* contributed equally, # contributed equally, § presenting author

Aging is an inevitable risk factor for cardiovascular diseases. Profound understanding of mechanisms underlying the early signs of cardiovascular aging in humans is mandatory to develop novel therapeutic approaches. Therefore, animal models which closely reflect the human condition are highly sought after. Here, we investigated cardiovascular natural aging in a non-human primate, comparing healthy young-adult (2-4 years) and aged (>8 years) common marmosets (Callithrix jacchus). Despite preservation of most conventional non-invasive cardiac functional parameters in aged animals, pressure-volume-loop measurements revealed a decreased ejection fraction (65% in aged vs. 83.7% in young-adults, P < 0.05). Non-HDL/HDL ratio was also significantly increased in aged animals (2.195 ± 0.764, P = 0.0151). Importantly, significant histological alterations were observed in aged hearts, including interstitial and perivascular fibrosis, as well as microvascular rarefaction. Moreover, aged cardiomyocytes displayed increased heterogeneity in cell size distribution, as well as increased waviness of myofibrillar structures. Single-nuclei RNA-sequencing revealed cardiac stress, pro-inflammatory and fibrotic gene programs aligning with histological findings. Importantly, analysis of cardiac extracellular vesicles (EVs) from younger animals revealed a cardioprotective protein cargo and pro-angiogenic properties in human cardiac microvascular endothelial cells. Aged cardiac EVs, on the other hand, were enriched for pro-hypertrophic, pro-inflammatory and atherogenic protein cargo with higher ligand-receptor pairing communicative potential to cardiac cell clusters, as well as large vessels. Finally, large vessels’ atherosclerosis was strikingly evident in aged animals and molecularly elucidated by bulk RNA-sequencing. Overall, the aging marmoset model offers a great potential for translational cardiovascular research.