Storage effect on viability and biofunctionality of human adipose tissue-derived stromal cells

Background aims. In our recent studies, the transplantation of human adipose tissue derived stromal cells (ASCs) has shown promise for treatment of diseases related to bone and joint disorders. Methods. For the current clinical applications, ASCs were formulated and suspended in PlasmaLyte A supplemented with heparin, glucose and human serum albumin, balanced to pH 7.4 with sodium bicarbonate. This cell solution constitutes 20% of the overall transplanted mixture and is supplemented with hyaluronic acid (60%) and OraGraft particles (20%). We intended to investigate the effect of this transplantation mixture on the viability and biofunctionality of ASCs in bone formation. Freshly harvested cells were resuspended and incubated in the indicated mixture for up to 48 h at 4 degrees C. Cell viability was assessed using trypan blue and AlamarBlue, and cell functionality was determined by quantifying their adhesion rate in vitro and bone formation in an ectopic mouse model. Results. More than 80% of the ASCs stored in the transplantation mixture were viable for up to 24 h. Cell viability beyond 24 h in storage decreased to approximately 50%. In addition, an equal degree of bone formation was observed between the cells transplanted following incubation in transplantation mixture for up to 24 h and zero-time non-incubated cells (control). Conclusions. The viability and functionality of ASCs stored in the presented formulation will make such cell therapy accessible to larger and more remote populations.