en تکثیر سلول‌های بنیادی/پیشتاز غنی نشده CD34+CD38- با استفاده از سلول‌های کبدی مقاله کامل Full Length/Original Article <span><font face="times new roman,times,serif">Many investigators have used xenogeneic, especially murine stromal cells and fetal calf serum to maintain and expand human stem cells. The proliferation and </font><a name="hit5"></a><font face="times new roman,times,serif">expansion of human hematopoietic </font></span><a name="hit6"></a><span><font face="times new roman,times,serif">stem cells in <i>ex vivo</i> culture were examined with the goal of generating a suitable protocol for expanding hematopoietic stem cells for patient transplantation. Using primary fetal liver cells, we established a serum-free culture system to expand human primitive stem/progenitors cells.</font><a name="toc2"></a><font face="times new roman,times,serif"> Non-enriched cord blood CD34⁺ cells were cultured on a monolayer of mouse primary fetal liver cells in the presence of trombopoietin, flt3/flk2 ligand, and/or stem cell factor, IL-6 and IL-3 under serum-free conditions. After 1 or 2 weeks of culture, cells were examined for clonogenic progenitors and </font><a name="toc3"></a><font face="times new roman,times,serif">percentage of CD34⁺ CD38^- cells.<span style="mso-spacerun: yes"><font size="3">&nbsp; </font></span>In the presence of trombopoietin, flt3/flk2 ligand, and stem cell factor, fetal liver cells supported expansion of CD34⁺ cells more than 10 to 20 fold. In addition, colony forming unit-cell assay was expanded more than 5- and 10-fold after 1 and 2 weeks of culture, respectively.<span style="mso-spacerun: yes"><font size="3">&nbsp; </font></span></font><a name="toc4"></a><font face="times new roman,times,serif">These results strongly suggest that fetal liver cells may be a suitable feeder layer for </font><a name="hit9"></a><font face="times new roman,times,serif">expansion of hematopoietic progenitors from umbilical cord blood <i>in vitro</i></font></span> Ex vivo expansion, Stem cells, Umbilical cord blood, Fetal liver cells 111 116 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-1-200&slc_lang=en&sid=1 Masoud Soleimani مسعود سلیمانی No Hossein Mozdarani حسین مزدرانی mozdarah@modares.ac.ir Yes AliAkbar Pourfathollah علی اکبر پورفتح ا... No Yousef Mortazavi یوسف مرتضوی No Kamran Alimoghaddam کامران علی مقدم No Mahin Nikogoftar مهین نیکوگفتار No Zahra Zonobi زهرا زنوبی No Abbas Hajifathali عباس حاجی فتحعلی No