1. ¹Stem Cell Biology Program at James Graham Brown Cancer Center, University of Louisville, Louisville, KY, USA
2. ²Department of Pathology and Pathophysiology, Pomeranian Medical University, Szczecin, Poland

Correspondence: Dr MZ Ratajczak, Stem Cell Biology Program, University of Louisville, 580 S. Preston St., Baxter II, Rm. 119E, Louisville, KY 40202, USA. E-mail: mzrata01@louisville.edu

Received 25 September 2006; Accepted 11 October 2006; Published online 30 November 2006.

Abstract

Recently, we purified from adult murine bone marrow (BM) a population of CXCR4⁺, Oct-4⁺ SSEA-1⁺, Sca-1⁺ lin^- CD45^- very small embryonic-like (VSEL) stem cells and hypothesized that similar cells could be also present in human cord blood (CB). Here, we report that by employing a novel two-step isolation procedure – removal of erythrocytes by hypotonic lysis combined with multiparameter sorting – we could isolate from CB a population of human cells that are similar to murine BM-derived VSELs, described previously by us. These CB-isolated VSELs (CB-VSEL) are very small (3–5 m) and highly enriched in a population of CXCR4⁺AC133⁺CD34⁺lin^- CD45^- CB mononuclear cells, possess large nuclei containing unorganized euchromatin and express nuclear embryonic transcription factors Oct-4 and Nanog and surface embryonic antigen SSEA-4. Further studies are needed to see if human CB-isolated VSELs similar to their murine BM-derived counterparts are endowed with pluripotent stem cell properties.