“The research team has published a new study, which shows that aside from the usual mitochondrial populations living inside our cells, there are also wandering mitochondria floating around in our bloodstreams. From time to time, mitochondria are found outside the cells, but only in the context of debris within platelets, so what are these intrepid mitochondria doing out there alone in the bloodstream?”

https://www.leafscience.org/mitochondria-found-independently-living-in-blood/