Clinical grade adult stem cell banking

Abstract

There has been a great deal of scientific interest recently generated by the potential therapeutic applications of adult stem cells in human care but there are several challenges regarding quality and safety in clinical applications and a number of these challenges relate to the processing and banking of these cells ex-vivo. As the number of clinical trials and the variety of adult cells used in regenerative therapy increases, safety remains a primary concern. This has inspired many nations to formulate guidelines and standards for the quality of stem cell collection, processing, testing, banking, packaging and distribution. Clinically applicable cryopreservation and banking of adult stem cells offers unique opportunities to advance the potential uses and widespread implementation of these cells in clinical applications. Most current cryopreservation protocols include animal serum proteins and potentially toxic cryoprotectant additives (CPAs) that prevent direct use of these cells in human therapeutic applications. Long term cryopreservation of adult stem cells under good manufacturing conditions using animal product free solutions is critical to the widespread clinical implementation of ex-vivo adult stem cell therapies. Furthermore, to avoid any potential cryoprotectant related complications, reduced CPA concentrations and efficient post-thaw washing to remove CPA are also desirable. The present review focuses on the current strategies and important aspects of adult stem cell banking for clinical applications. These include current good manufacturing practices (cGMPs), animal protein free freezing solutions, cryoprotectants, freezing & thawing protocols, viability assays, packaging and distribution. The importance and benefits of banking clinical grade adult stem cells are also discussed.

Keywords: adipose derived stem cells; clinical banking; cryopreservation; current good manufacturing practice; dental pulp derived stem cells; mesenchymal stem cells; placenta derived stem cells.

Figure 1

In vitro differentiation potential of frozen-thawed adipose derived adult stem cells (ASCs). When culture expanded, ASCs exhibit a spindle shaped fibroblastic morphology (Top image, stained with Toludine blue, 40×). Under appropriate inducing conditions, the culture of frozen thawed ASCs will demonstrate adipogenic differentiation as evidenced by lipid accumulation (A, stained with Oil Red O, 40×) or osteogenesis as seen by calcium deposition (B, stained with Alizarin Red, 10×).

Figure 2

Dental pulp stem cells (DPSCs) recovered from frozen thawed pulp tissue expanded to passage 3 were then cultured in osteogenic (A), chondrogenic (B) or adipogenic (C) differentiation medium for three weeks before staining with an alkaline phosphatase kit, Alcian blue, and Oil red O respectively.