Ex vivo culture of human CD34+ cord blood cells with thrombopoietin (TPO) accelerates platelet engraftment in a NOD/SCID mouse model

Human platelets produced in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice upon transplantation of human cord blood CD34+ cells are functionally active in an ex vivo flow model of thrombosis

“…Levels reported before 7 days after transplantation were less than 100 platelets/L, which would have remained undetected in our system because of differences in flow cytometry protocols used to measure human platelets in NOD/SCID PB. All of these observations, in addition to similar levels of human platelet production observed few days after transplantation with expanded CB-or PB-CD34 ϩ cells, 20,21,25,27 suggest that delayed human platelet production after transplantation of umbilical CB-versus mobilized PB-HSC may be attributed to the numbers of injected CD34 ϩ rather than to differences in homing capacity or maturation of the transplanted cells in the NOD/SCID recipient. 41 In addition to an earlier production of human platelets, we also detected a platelet production peak 2 weeks after transplantation corresponding to up to 87 ϫ 10 3 human platelets/L, and a second wave of platelet formation after 5 weeks with levels as high as 20 ϫ 10 3 platelets/L still detected 8 to 9 weeks after transplantation.…”

“…17 Several groups have demonstrated that injection of human CD34 ϩ cells from PB and CB into NOD/SCID mice can lead to the production of human platelets, with some variation, however, in the yield. 5,[18][19][20][21][22][23][24][25][26][27] Differences in engraftment potential between CB and PB HSC are reflected in the megakaryocytic lineage with several CB studies showing a peak production of human platelets in NOD/SCID mice toward 4 to 9 weeks after injection, 20,21,23,27 whereas a peak was described 3 weeks after injection of CD34 ϩ cells isolated from PB. 18,19,22 Onset of human platelet formation in CB-CD34 ϩ -injected mice varied from few days to 2 to 3 weeks, albeit modest numbers were reported few days after transplantation.…”

“…18,19,22 Onset of human platelet formation in CB-CD34 ϩ -injected mice varied from few days to 2 to 3 weeks, albeit modest numbers were reported few days after transplantation. 20,21,23,27,28 The advantage of culturing CB-or PB-CD34 ϩ cells in medium containing cytokine mixtures before transplantation has been demonstrated by several groups up to a few days after transplantation, 20,25,27 whereas no benefits were observed for longer Submitted February 18, 2009; accepted August 18, 2009. Prepublished online as Blood First Edition paper, September 9, 2009; DOI 10.1182 DOI 10.…”

“…on May 10, 2018. by guest www.bloodjournal.org From periods after transplantation. 20,22,25,27 Finally, functionality of human platelets produced in mice has to date only been demonstrated by flow cytometry, in which platelets were activated ex vivo with thrombin/TRAP. 19,20,22,24,25 Besides studies of human platelet production for transplantation procedures, there is a growing interest in developing antiplatelet therapeutics, 29 in which mouse models of thrombosis have been mostly used; but the emergence of new models in which human platelets are injected into mice demonstrated the feasibility of studying the more relevant effects on human platelet function in vivo.…”

Pretreatment with Interferon-γ Enhances the Therapeutic Activity of Mesenchymal Stromal Cells in Animal Models of Colitis

“…In brief, human MSCs were washed twice with PBS by centrifugation in a two-step washing process (5 minutes at 150 Â g). Cell labeling with technetium-99m was performed according to a leukocyte-labeling method that had been modified for stem cells [19,20]. A lipophilic reactive complex was prepared by adding tropolone to a solution of SnCl 2 in a ratio of 2:1, which was then added to a solution of KBH 4 and 99m Tc-sodium pertechnetate (200-500 MBq/mL, Technekow, Tyco Healthcare, Mallinckrodt Medical BV, Petten, The Netherlands).…”