Mesenchymal stromal cells (also called mesenchymal stem cells) is the name for a super heterogenous cell type that can be derived from pretty much any tissue. Bone marrow, umbilical cord, foreskin, teeth, you name it.
The cool thing about them (aside from the fact that I am spending at least 4 years of my life running experiments with them) is that you can take them out of a person, grow them in a dish until you have many more, and then transplant them into a patient with some kind of inflammatory disease or tissue damage.
Diseases that fall under this are, for example, graft vs host disease (bone marrow transplant starts attacking the patient), acute respiratory distress syndrome (it's ... what it sounds like, your lungs are having a really bad time), cardiac fibrosis (when that heart gets scarred), etcetera etcetera.
It's not really ripe for commercial use yet, probably because there is so much we do not know yet.
How you transplant them kind of depends on what your goal is. If you give them through intravenous injection, they tend to accumulate in the lungs. Which is great when you want to treat something in the lungs, and kind of shitty if you want to treat something in the pancreas.
On my quest to write a literature review for my PhD (oh, the joy of academia), I've run into a paper that investigates why the mesenchymal stromal cells accumulate in the lungs (https://www.nature.com/articles/s41598-021-83894-7). The short answer? They get stuck.
And now to share with you the first thing that popped into my mind when I read that:
Thanks, I hate it too.
That's enough procrastination, see you all around!