A Novel Route of Transplantation of Human Cord Blood Stem Cells in Preimmune Fetal Sheep: The Intracelomic Cavity

Abstract

The intracelomic route for in utero hematopoietic stem cell transplantation was evaluated in preimmune fetal sheep and the engraftment characteristics were defined. Twelve twin ovine fetuses (gestational age: 40-45 days) received intracelomic transplants of human CD3-depleted (50 × × 10 6 per lamb) or CD34-selected (1-2 × × 10 5 per lamb) cord blood hematopoietic stem cells. Engraftment was evaluated from cell suspensions of the liver, spleen, bone marrow, and thymus by flow cytometry, cloning assays, and polymerase chain reaction (PCR) analyses of human β β2-microglobulin. Four fetuses (33%) aborted shortly after intracelomic transplantation and were not evaluable for engraftment. Engraftment was detected in four fetuses obtained from cesarean delivery on day 70 after transplantation of CD3-depleted cord blood cells. The degrees of engraftment in these four fetuses ranged from 6%-22% in the different organs (as revealed by antigenic analysis of human CD45 with flow cytometry). Three fetuses obtained after cesarean section at 102 (no. 435184) and 105 (no. 915293, no. 037568) days and one fetus delivered at term that received CD34-selected cord blood cells had human engraftment with 10%, 32%, 20%, and 10% CD45 + cells in bone marrow, respectively. In six of eight fetuses evaluable for human engraftment, chimerism was confirmed by PCR analysis for human β β2-microglobulin, which also identified human cells in brain, spinal cord, heart, lung, and skeletal muscle. This preliminary study indicates that intracelomic transplantation of human hematopoietic stem cells in fetal lambs is feasible and effective in terms of hematopoietic engraftment. Stem

Prolonged human/sheep cellular chimerism following transplantation of human hemopoietic stem cellsinto the ewe celomic cavity

“…These results raise several interesting points: 1) The high rate of abortion and the too low level of engraftment agree with results of other groups using sheep/human xenogeneic in utero transplantation methods (Young et al, 2003;Schoeberlein et al, 2004;Oppenheim et al, 2001) but in contrast with other reports documenting higher engraftment levels in sheep (Zanjani et al, 1992;Noia et al, 2003;Gammaitoni et al, 2003). One plausible explanation is that this route of injection is less efficient than in utero transplantation because different HSC, particularly if isolated from different donors and if injected too early to ewes, may not be equally feasible.…”

“…Transplantation into the celomic cavity was performed on 19 ewes (Group A), as previously described (Noia et al, 2003). Only one fetus of the 2 or 3 siblings of each pregnant sheep was injected with 270,000-647,000 CD133 + HSC.…”

“…This procedure allows successful HSC engraftment, survival and efficient distribution throughout the body of the fetus. Recently, a novel successful route of human HSC engraftment, employing transplantation of HSC into the celomic cavity of pregnant ewes early in gestation (40-46 days), has been described (Noia et al, 2003).…”

A Study to Determine if Human Umbilical Cord Hematopoietic Stem Cells Can Survive in Baboon Extra-Embryonic Celomic Fluid: A Prerequisite for Determining the Feasibility of in-utero Stem Cell Xeno-Transplantation via Celocentesis

“…ical composition of the celomic fluid [14][15][16][17][18][19][20][21][22][23][24] , (2) diagnosis of a variety of genetic disorders [11,[25][26][27][28][29][30] , and (3) in sheep, for in-utero somatic stem cell therapy [6] . However, as mentioned earlier, development of the extra-embryonic celome and functions of the celomic fluid and placenta in sheep and primates are different.…”

“…In the pregnant sheep animal model, human hematopoietic stem cells have been administered into the celomic cavity and engraftment demonstrated during fetal life [6] . These findings may suggest that in-utero stem cell transplantation via celocentesis has potential for becoming a very early therapeutic option for parents carrying embryos affected with a number of inborn errors of metabolism.…”