Basically, exosomes are little vesicles secreted by growing cells (including stem cells) that influence their environment and the cells around them.
Why influence other cells? To Repair
Repair is a complex symphony of different cells all acting in a coordinated manner. So, for example, some cells are told to become blood vessels and others to remove debris.
Thus Stem cells act as the conductor of that symphony and directs other cells what to do.
The MSc cells excrete the exosomes in response to what they detect is needed. MSc cell coordinates which exosomes are needed and when. Thus Stem cells control exosomes to do their function
Exosomes are like the paint on a canvas. You can get art by randomly throwing paint on a canvas (think abstract art, like Jackson Pollock), but most art requires a brain that controls a hand that applies the paint. So exosomes without stem cells are like paint without an artist, as the
Exosomes carry mRNA-which are instruction template to make proteins, thus protein factories. Stem cell exosomes have over 268 growth factor proteins.
Exosomes are like extended hands of stem cells and stem cell directs them to the cell which stem cell wants to influence. Once they are near or in the cell they dump mRNA into the contact cell. Thus it is a cell to cell communication vesicle, full of many growth factors. It goes and dumps products in the other cell where it is directed. Then the mRNA factory begins to pump out the proteins that stem cell wants mRNA to do and start repair process.
Exosomes quality assay results confirm the presence of cell signaling components (e.g. cytokines, chemokines, mRNA, and MiRNAs)