A novel and feasible way to cultivate and purify endothelial progenitor cells from bone marrow of children with congenital heart diseases

Background Endothelial progenitor cells （EPCs） are used in vascular tissue engineering and clinic therapy. Some investigators get EPCs from the peripheral blood for clinic treatment, but the number of EPCs is seldom enough. We have developed the cultivation and purification of EPCs from the bone marrow of children with congenital heart disease, to provide enough seed cells for a small calibre vascular tissue engineering study. Methods The 0.5-ml of bone marrow was separated from the sternum bone, and 5-ml of peripheral blood was collected from children with congenital heart diseases who had undergone open thoracic surgery. CD34＋ and CD34＋NEGFR＋ cells in the bone marrow and peripheral blood were quantified by flow cytometry. CD34＋/VEGFR＋ cells were defined as EPCs. Mononuclear cells in the bone marrow were isolated by Ficoll density gradient centrifugation and cultured by the EndoCult Liquid Medium KitTM. Colony forming endothelial cells was detected. Immunohistochemistry staining for Dil-ac-LDL and FITC-UEA-1 confirmed the endothelial lineage of these cells. Results CD34＋ and CD34＋NEGFR＋ cells in peripheral blood were （0.07±0.05）% and （0.05±0.02）%, respectively. The number of CD34＋ and CD34＋/VEGFR＋ cells in bone marrow were significantly higher than in blood, （4.41±1.47）% and （0.98±0.65）%, respectively （P 〈0.0001）. Many colony forming units formed in the culture. These cells also expressed high levels of Dil-ac-LDL and FITC-UEA-I. Conclusion This is a novel and feasible approach that can cultivate and purify EPCs from the bone marrow of children with congenital heart disease, and provide seed cells for small calibre vascular tissue engineering.

An improved anti-leukemic effect achieved with donor progenitor cell infusion for relapse patients after allogeneic bone marrow transplantation

Objective To observe the antileukemic effect in relapse patients by infusion of donor immunocompetent cells with or without granulocyte colony-stimulating factor (G-CSF) mobilization.Methods Twenty patients with leukemia in relapse after allogeneic bone marrow transplantation (allo-BMT) were treated with chemotherapy followed by donor-derived lymphocytes (DDL) without G-CSF mobilization (Group A, n=11), or donor peripheral blood progenitor cells (PBPCs) with G-CSF mobilization (Group B, n=9).Results Five patients in Group A were in hematologic relapse. After DDL infusion, 3 of 5 patients had a temporary complete remission (CR) and relapsed after 3, 7 and 10 months, respectively. One achieved partial remission and died of interstitial pneumonia; and the other one showed no response. Another 6 patients in Group A were in cytogenetic relapse or central nerve system (CNS) leukemia, and all achieved CR and remained in disease free survival (DFS) for 10 to 98 months after DDL infusion. All 9 patients in group B were in hematologic relapse. Three patients with chronic myeloid leukemia (CML) had cytogenetic and molecular remission for 16, 35 and 51 months, respectively after PBPC infusion; and 5 patients with acute lymphoid leukemia (ALL) had CR and were still in CR for 10 to 18 months except 1 patient relapsed soon. And the other one with AML showed no response to the therapy.Conclusion Donor immunocompetent cells infusion is an effective therapy for relapsed leukemia after allo-BMT, especially for the patients with early (molecular and cytogenetic) or CNS relapse. Infusion of donor PBPC mobilized by G-CSF seems to have more potentiated graft-versus-leukemia (GVL) effect than DDL infusion.