Practical and Safe Method of Long-Term Cryopreservation for Clinical Application of Human Adipose-Derived Mesenchymal Stem Cells Without a Programmable Freezer Or Serum.

BACKGROUND

Adipose-derived mesenchymal stem cells (ADSCs) have emerged as a promising modality for cellular therapy. However, techniques of ADSC cryopreservation, which can facilitate their clinical application, haven't been established yet.

OBJECTIVE

To determine optimal conditions for ADSC cryopreservation.

MATERIALS AND METHODS

We used three cryoprotectants [serum containing 10% dimethyl sulfoxide; CP-1 (5% dimethyl sulfoxide, serum-free); Stem-CellBanker (dimethyl sulfoxide and serum-free)], two storage temperatures (-80°C, -150°C) and two cell densities (1 × 10, 7 × 10 cells/mL). Storage was up to 18 months using cryovials. We didn't use a rate-controlled freezer or liquid nitrogen storage.

RESULTS

We found that CP-1 was a suitable cryoprotectant. Storage at -150°C and higher cell density (7×10 cells/mL) kept the best viability of ADSCs, but storage at -80°C and a lower cell density (1×10 cells/mL) is acceptable for up to 9 months. We also confirmed large quantities of ADSCs, stored with CP-1 in a cryobag, were still viable after -150°C cryopreservation for 24 months.

CONCLUSION

We have developed a safe, cost-effective way to cryopreserve ADSCs that could be used in the clinical setting.