Interesting thing from reading the paper was that they deliberately didn't purify the olfactory ensheathing cells from the olfactory mucosa (OM) biopsy, as other work has shown it to be less effective if purified. So there may be other cell types or molecular factors at play here as well.

Another group has previously found some mesenchymal stem cells (MSCs) in the OM - or at least, cells with known MSC markers - so that's also a possibility for aiding repair. Very much looking forward to seeing where this research heads anyway.