The Effect of Vasoactive Intestinal Peptide on Cord Blood CD34 (+) Cells / 대한소아혈액종양학회지

PURPOSE: We investigated the expression of vasoactive intestinal peptide (VIP), VIP receptor 1 (VPAC1), VIP receptor 2 (VPAC2) genes in the human umbilical cord blood CD34 cells, and the ability of VIP to stimulate human primitive as well as monopotent hematopoietic progenitors. METHODS: We isolated RNA from umbilical cord blood CD34 cells, and then performed RT-PCR, and sequencing. The umbilical cord blood CD34 cells were cultured with the various concentrations of VIP for burst-forming unit of erythrocyte (BFU-E), colony-forming unit of granulocyte/monocyte (CFU-GM), colony-forming unit of graulocyte/erythrocyte/monocyte/megakaryocyte (CFU-GEMM), and colony-forming unit of megakaryocyte (CFU-Mk). RESULTS: The RNA coding for VPAC1 was detected in human umbilical cord blood CD34 cells. VIP significantly stimulated the growth of CFU-GEMM and CFU-Mk. CONCLUSION: The present results suggest that VIP is an important neuropeptide in the early proliferation of human primitive as well as megakaryocyte progenitors.

Megakaryocyte Colony Formation of Fetal Liver Cells

PURPOSE: This study was undertaken to obtain basic data about the megakaryocyte colony formation of fetal liver cells by using immunocytochemical staining and ex vivo culture with growth factors. METHODS: The mononuclear cells were isolated from fetal liver and bone marrow with idiopathic thrombocytopenic purpura(ITP) and pancytopenia. These mononuclear cells were cultured in MegaCultTM-C(Stem Cell Tech, Canada) media in the presence of growth factors and CFU-Megakaryocyte(CFU-Mk) colonies were counted on day 12. The expansion of CD34+ and CD41+ cell was analyzed by flow cytometry after 5 days incubation using flask culture. RESULTS: The numbers of CFU-Mk colonies of mononuclear cells obtained from fetal liver in the 11th week gestational age were more than those in the 19th week specimens; growth factors could not enhance the colony expansion in all cases. Total numbers of CFU-Mk colony of fetal liver cells were higher than bone marrow from ITP or pancytopenia groups. The numbers of pure or large CFU-Mk colonies of fetal liver cells were also higher than bone marrow specimens. The rate of CD34+ cell expression of fetal liver was increased after flask culture and the enhancement effect of epression was seen only in cases which added thrombopoietin. The rate of CD41+ cell expression of fetal liver was increased after incubation, but the enhancement effect of growth factors was unclear. CONCLUSION: This study revealed good results about the megakaryocyte colony assay of fetal liver mononuclear cells using MegaCultTM-C media. This study suggests that the fetal liver could be a good source of megakaryocytic progenitor cells for clinical application in hematopoietic stem cell transplantation.

Rotor Off Fraction Might Contribute Early Platelet Recovery after Syngeneic Transplantation in Mouse / 대한혈액학회지

BACKGROUND: Rotor off (R/O) fraction obtained by counterflow centrifugal elutriation (CCE) contains small number of T cells and many hematopoietic stem cells. Since megakaryocytes and its progenitors are larger than other cells in bone marrow, it may be easier to be separated by CCE and newly applied to hematopoietic stem cell transplantation (HSCT) for early megakaryocytes reconstitution. METHODS: The marrow cells of BALB/c mice in each group (17, 25, 28mL/min, and R/O fraction) were cultured for quantifying CFU-MK and measured after 10 days. BALB/c mice were lethally irradiated and transplanted with R/O cells. The dosages of transplanted cells were 5x104 in Group A, 5x105 in Group B, and 5x106 in Group C. The platelet counts in peripheral blood were measured up to post-transplant day 14. RESULTS: After CCE, recovery rate of the loaded cells was 82.2% and the R/O fraction was 35.9%. Most CFU-MK were formed in R/O fraction, and Group C showed the fastest recovery. Group A couldn't reach the level of 100x109/L until post-transplant day 14, and Group B showed slower recovery compared to Group C. All 5 mice survived in Group C, but 2 out of 5 mice survived in Group A and B. CONCLUSIONS: R/O fraction contains higher number of megakaryocyte progenitors, and CCE could be an effective method for separating megakaryocyte progenitors essential for reconstituting platelet after HSCT. The cell dose of 5x106 was required for the effective recovery of platelet and the survival of BALB/c mice in syngeneic bone marrow transplantation with R/O cells.