%0 Journal Article
%T Proteomic Profiling of Ex Vivo Expanded CD34-Positive Haematopoetic Cells Derived from Umbilical Cord Blood
%A Heiner Falkenberg
%A Teja Falk Radke
%A Gesine K£¿gler
%A Kai St¨¹hler
%J Stem Cells International
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/245695
%X Ex vivo expansion of haematopoetic cells by application of specific cytokines is one approach to overcome boundaries in cord blood transplantation due to limited numbers of haematopoetic stem cells. While many protocols describe an effective increase of total cell numbers and the amount of CD34-positive cells, it still remains unclear if and how the procedure actually affects the cells¡¯ properties. In the presented publications, CD34-positive cells were isolated from cord blood and expanded for up to 7 days in media supplemented with stem cell factor (SCF), thrombopoietin (THPO), interleukin 6 (IL-6), and fms-related tyrosine kinase 3 ligand (FLT3lg). At days 3 and 7, expanded cells were harvested and analyzed by flow cytometry and quantitative proteomics. 2970 proteins were identified, whereof proteomic analysis showed 440 proteins significantly changed in abundance during ex vivo expansion. Despite the fact that haematopoetic cells still expressed CD34 on the surface after 3 days, major changes in regard to the protein profile were observed, while further expansion showed less effect on the proteome level. Enrichment analysis of biological processes clearly showed a proteomic change toward a protein biosynthesis phenotype already within the first three days of expression. 1. Introduction Although several groups in preclinical and clinical settings have attempted ex vivo expansion of the cord blood (CB) product in order to increase haematopoetic progenitor and granulocyte numbers and to reduce the duration of posttransplant neutropenia (summarized in [1]), the implementation of protocols applying for instance several cytokines has been complicated by the following facts. (1)CB transplants are frozen in the majority of banks in a single bag. Clinical trials were performed with only a fraction of CB unit expanded ex vivo with the larger remainder infused unmanipulated. Therefore, the expanded product usually could be infused only 10¨C14 days after transplantation. Alternative approaches focus on the expansion of one CB unit together with a second nonmanipulated unit. (2)Clinical grade growth factors are only available for a limited number of cytokines and are expensive. (3)Moreover, none of the clinical experiences could unequivocally document a clear benefit of infusion of such ex vivo cytokine expanded components. Since cytokine-driven ex vivo expansion of CD34+ cells from CB is being discussed controversially, other ways to improve haematopoetic engraftment time and reconstitution after CB transplantation are being explored including double CB
%U http://www.hindawi.com/journals/sci/2013/245695/