Olfactory tissue and regeneration medicine

Regeneration medicine is divided mainly into differentiation-induced and cell replenishment therapy. Bone marrow includes stem cell populations such as hematopoietic, mesenchymal and so on. These stem cells are shown experimentally and clinically to be pluripotent. It remains unclear, however, whether bone-marrow-derived cells differentiate into olfactory neurons and are engrafted as olfactory stem cells into olfactory tissue. We transplanted bone marrow cells of green fluorescence protein (GFP) mice into lethally irradiated recipients. Double immunostaining for GFP and olfactory marker protein or cytokeratin showed the possibility that bone-marrow-derived cell population could do as hoped. Because the engraftment rates of this study were low far from a practical level, methimazole inducing selectively apoptosis into olfactory tissue and granulocyte colony-stimulating factor known to mobilize stem cells from bone marrow into circulation were added to a series of experiments, which increased engraftment rates. Whether bone-marrow-derived cells or mesenchymal stem cells differentiate into olfactory cells remains controversial, necessitating the evaluation of regeneration medicine using such cells in further olfactory disorder studies.