Stem Cells, Vol 13, 533-540, Copyright © 1995 by AlphaMed Press
Density separation of umbilical cord blood and recovery of hemopoietic progenitor cells: implications for cord blood banking
C Almici, C Carlo-Stella, L Mangoni, D Garau, L Cottafavi, A Ventura, M Armanetti, JE Wagner and V Rizzoli
Department of Hematology, University of Parma, Italy.
Umbilical cord blood (CB) has been evaluated as a potential source of
hematopoietic stem cells suitable for clinical use in the transplantation
setting. Previous reports have documented a significant loss of progenitor
cells by any manipulation other than cryopreservation. We have evaluated
the feasibility of fractionating and cryopreserving CB samples with minimal
loss of progenitor cells. We have compared various separation procedures
based on different density gradients in the attempt to obtain the highest
depletion of red blood cells (RBC) while maintaining the highest recovery
of progenitor cells. We compared three different densities of Percoll
(1.069 g/ml, 1.077 g/ml, 1.084 g/ml), sedimentation over poligeline (Emagel
) and sedimentation over poligeline followed by separation over
Ficoll/Hypaque (F/H). Separated samples (n = 25) were analyzed for recovery
of CD34+ cells and progenitor cells (CFU-GEMM, BFU-E, CFU-GM). Separation
by sedimentation over poligeline followed by F/H allowed the highest
depletion of RBC (hematocrit of the final cellular suspension 0.4 +/- 0.1%)
while maintaining high recovery of CD34+ cells (85.3 +/- 5.6%) and total
recovery for CFU-GEMM, BFU-E and CFU-GM. After cryopreservation, recovery
of clonogenic progenitors was 82% for CFU- GEMM, 94% for BFU-E, 82% for
CFU-GM and 90% for colony-forming units (CFUs) after five weeks of
long-term culture (LTC). We further evaluated the effect of stem cell
factor (SCF) on the in vitro growth of hemopoietic progenitors and on
replating efficiency.(ABSTRACT TRUNCATED AT 250 WORDS)
