Figure 1. Mitochondrial DNA in extracellular vesicles and association with human aging. Damage to mitochondria can lead to release of mitochondrial components, including mitochondrial DNA (mtDNA). Circulating cell-free mtDNA (ccf-mtDNA) can be released into the circulation. It can also be encapsulated into extracellular vesicles (EVs). Three main types of EVs are indicated and the possible mechanism for incorporation of mitochondrial components. Alternatively, damaged mitochondria can be degraded via the mitophagy pathway. (B) Schematic representation showing decreased circulating EV mtDNA levels with human age.