Enhanced In Vivo Homing of Uncultured and Selectively Amplified Cord Blood CD34+ Cells by Cotransplantation with Cord Blood-Derived Unrestricted Somatic Stem Cells

Abstract

Mesenchymal stem cells have been implicated as playing an important role in stem cell engraftment. Recently, a new pluripotent population of umbilical cord blood (UCB) cells, unrestricted somatic stem cells (USSCs), with intrinsic and directable potential to develop into mesodermal, endodermal, and ectodermal fates, has been identified. In this study, we evaluated the capacity of ex vivo expanded USSCs to influence the homing of UCB-derived CD34+ cells into the marrow and spleen of nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. USSCs induced a significant enhancement of CD34+ cell homing to both bone marrow and spleen (2.2 ± 0.3- and 2.4 ± 0.6-fold, respectively; p < .05) reduction in USSC-mediated enhancement of CD34+ homing. Our findings thus suggest a clinical potential for using USSCs in facilitating homing and engraftment for cord blood transplant recipients.