In tissue engineering, scaffolds are vitalized by cells in vitro. Human mesenchymal stem cells (hMSC) are very interesting because of their ability to differentiate towards the osteogenic lineage and their self renewing capacity. Yet, it is important that implanted cells do not disseminate and exhibit unwanted cell growth outside the implantation site. Therefore the aim of this study was to detect migrated cells in organs of mice after implantation of a composite (cell-scaffold) substitute.

HMSC (Cambrex, USA) were inoculated on a clinically approved 3D scaffold (Tutobone(TM), Tutogen, Germany). One composite and one scaffold without cells were implanted subcutanously, left and right paravertebrally in athymic nude mice (nu/nu). After 2, 4, 8 and 12 weeks constructs were explanted and organs (liver, spleen, lungs, kidney, heart, testicles, brain and blood) were harvested. The entire organs were homogenized and genomic DNA was isolated for qualitative and quantitative PCR.

Human DNA was found in all explanted composites at all examined time points. No human DNA could be detected in control scaffolds. Moreover we did not detect human DNA in all explanted organs at any time point. As internal controls we could detect 1 single hMSC in a pool of 106 mouse cells.

In conclusion, we could proof that cells of implanted composite substitutes do not migrate to other organs. Furthermore, this study showed that implanted hMSC seeded on 3D scaffolds survive over time frames up to 12 weeks.