We should be careful about which is which, because I think that the principle behind RCH-01 and Riken is pretty different.
Go to 3:20 (since this site doesn't allow time stamped embedding).
You see that what Ken has shown is that if you take dermal and epithelial cells and put them in a medium, they find each other and assemble into organoids and bear hair. The thinking then was, what if we injected both cells into the skin - wouldn't we expect the same?
Go to 5:00
What Replicel has shown is that if you only inject dermal sheath cup cells (which are thought to produce dermal papilla cells - the ones that actually make the hair), then they integrate themselves into existing dying follicles and rejuvenate them (they have also tried other cells but DSCs gave the best results so this is part of the "official" product). So no new follicles or massive density increase but maintenance.
Perhaps what happened with Aderans is that self-assembly of hair was expected but instead a maintenance therapy was discovered. I am not too sure.
What Tsuji is trying to do is create in lab the organ germ for a follicle, which is essentially a partially organized ball of epithelial and mesenchymal cells, and then to inject that germ into the scalp, where it should complete development and hopefully integrate very well with the scalp, for example connected to the arrector pili muscle, which in turn may direct the assembly of the follicle with the natural hair pattern alignment. The cool thing about Tsuji is that he has shown that this does indeed work as intended (in mice, even with using human cells). Now we wait for them to do it on humans
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As a side note, mesenchymal stem cells differentiate into several useful cell types, so solving this culturing problem is a big deal for Tsuji since he is interested in organ regeneration in general. His book Organ Regeneration is really cool stuff.
Perhaps someone more knowledgeable can correct and/or append me if I have stated anything incorrectly.