Immune suppressant stimulating mesenchymal to bone differentiation

Shanghai, China -

Mesenchymal stem cells are very useful since they can be administered across allogeneic barriers without need for immune suppression and can be differentiated into various tissues such as liver.

In a current paper (Dai et al. Stimulation of osteogenic activity in mesenchymal stem cells by FK506. J Biomed Mater Res A. 2007 Dec 13) the effect of the immunosuppressant FK506 was assessed on mesenchymal stem cells. FK506 is commonly used to prevent transplant rejection, it works by inhibiting the calcinurin pathway of T cell activation.

The researchers grow mesenchymal stem cells from rat bone marrow and exposed them to induction media for differentiation along the osteogenic lineage. It was shown that FK506 treatment induced increased formation of bone in vitro and in vivo.

In vitro analysis consisted of

- morphology,
- alkaline phosphatase (APase) activity,
- calcium deposition,
- bone nodule formation, and
- osteocalcin mRNA expression

In vitro bone formation was demonstrated by administration of ceramic cubes that were seeded with mesenchymal stem cells and FK506 and subcutaneously administered.

These data suggest the possibility of using drugs already in the clinic to induce in vivo differentiation of stem cells along specific lineages.

Also, this paper is of interest philosophically when one thinks of the recent paper in which Treg cells were demonstrated to inhibit osteoclast activity.