Small extracellular vesicles from young adipose-derived stem cells ameliorate age-related changes in the heart of old mice.

BACKGROUND: Aging entails a progressive decline in physiological functions, elevating the risk of age-related diseases like heart failure or aortic stenosis. Stem cell therapies, especially those that use paracrine signaling, can potentially mitigate the adverse effects of aging. OBJECTIVES: The objective is to explore the potential of small extracellular vesicles (sEVs) derived from young adipose-derived stem cells (ADSC-sEVs) in reversing structural, molecular, and functional changes associated with aging in the heart. METHODS: Aged C57BL/6J mice were treated intravenously with ADSC-sEVs from young mice or PBS as controls. Young mice were included to identify specific age-associated changes. The impact of sEV treatment on cardiac function was assessed using transthoracic echocardiography and physical endurance tests. Histological and molecular analyses were conducted on heart tissue to evaluate structural changes and markers of senescence, inflammation, and oxidative stress. A comprehensive metabolomic analysis was also performed on heart tissues to identify changes in metabolic profiles associated with aging and treatment status. RESULTS: The administration of ADSC-sEVs significantly improves several aging-associated cardiac parameters, including oxidative stress, inflammation, and cellular senescence reductions. We also report on the age-related reversal of myocardial structure and function changes, highlighted by decreased fibrosis and improved vascularization. Notably, echocardiographic assessments reveal that sEV treatments ameliorate diastolic dysfunction and left ventricle structural alterations typically associated with aging. Furthermore, the treatment shifts the heart metabolome towards a more youthful profile. CONCLUSIONS: These results denote the potential of ADSC-sEVs as a novel, noninvasive therapeutic strategy for mitigating cardiac aging-associated functional decline.