Effect of mineralized bone allograft scaffold with coverage of UCB-derived stromal cells on ex vivo expansion of CD34+ cells

Bone marrow transplantation with umbilical cord blood (UCB) in adult recipients is limited mainly by a low CD34+ cell dose. To overcome this shortcoming by minimum manipulation، mineralized bone allograft (MBA) scaffold coated by UCB-USSC (unrestricted somatic stem cells) was used to expand CD34+ cells from UCB. In this experimental study، UCB-USSCs were isolated and characterized by morphologic and immunophenotypical analysis. Then they were seeded on MBA (for 3D figuration) and culture plate (for 2D figuration) as a feeder layer. CD34+ cells were isolated from the UCB (by MACS method) and were expanded in 2D and 3D conditions for 3 weeks. At the end، cell count، flow cytometry، cologenic assay، and LTC-IC were done. After 3 weeks، ex vivo expansion of UCB-CD34+ was enhanced 250 ± 13. 2 in 3D. The highest CFC expansion and LTC-IC were observed at day 14. Flow cytometry analysis showed the lowest percentage in 3D culture. USSCs by 3D MBA structure produce the hematopoietic cytokine، extracellular matrix and binding molecules; they also create the intercellular interaction that can be used as a suitable feeder layer. It provides an ex vivo mimicry of bone marrow niche by enhancing surface/volume ratio. This model could be a suitable and alternative environment for HSCs expansion and hematopoiesis.