Hematopoietic stem cells (HSC) are characterized by their ability to undergo self-renewal and multi-lineage differentiation. A variety of in vitro assays have been used to assess and predict the in vivo potential of HSC from different human sources for these characteristics. It is understood, however, that the in vivo long-term proliferative potential of human HSC is generally not fully addressed by in vitro assays. The investigators have developed a large animal model of human hematopoiesis in sheep which permits the engraftment and multilineage differentiation of human HSC following transplantation in utero. In this model, they have reported (a) the long-term engraftment of human fetal and purified adult HSC, (b) the development of graft versus host disease (GVHD) with light density mononuclear cells (LMNC) from human post-natal sources, and (c) the induction of donor (human)-specific tolerance in chimeric lambs. The overall aims of the studies proposed here are to use the preimmune fetal/tolerized sheep as a model to investigate and compare the in vivo potential of native and ex- vivo expanded HSC from human cord blood, bone marrow, and peripheral blood with regards to (1) the long-term (stable) engraftment, self-renewal, and differentiation in non- myeloablated and myeloablated hosts, and (2) the development of GVHD in this human/sheep xenograft model. From each source the investigators plan to compare the in vivo activity of HSC present in light density mononuclear cells (LMNC), T-depleted LMNC, CD34+-enriched, and highly purified, sorted fractions under """"""""normal"""""""" and cytokine-induced """"""""stressed"""""""" conditions. It is hoped that these studies will help identify the source(s) and HSC preparation(s) likely to provide long- term in vivo reconstitution and with low risks of GVHD and HSC exhaustion.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
1R01DK051427-01
Application #
2152491
Study Section
Special Emphasis Panel (ZHL1-CSR-Q (S2))
Project Start
1995-09-30
Project End
1999-08-31
Budget Start
1995-09-30
Budget End
1996-08-31
Support Year
1
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Sierra Biomedical Research Corporation
Department
Type
DUNS #
783285752
City
Reno
State
NV
Country
United States
Zip Code
89502
Airey, Judith A; Almeida-Porada, Graca; Colletti, Evan J et al. (2004) Human mesenchymal stem cells form Purkinje fibers in fetal sheep heart. Circulation 109:1401-7
Almeida-Porada, Graca; Porada, Christopher; Zanjani, Esmail D (2004) Plasticity of human stem cells in the fetal sheep model of human stem cell transplantation. Int J Hematol 79:1-6
Almeida-Porada, Graca; El Shabrawy, Deena; Porada, Christopher et al. (2002) Differentiative potential of human metanephric mesenchymal cells. Exp Hematol 30:1454-62
Porada, Christopher D; Tran, Nam D; Almeida-Porada, Graca et al. (2002) Transduction of long-term-engrafting human hematopoietic stem cells by retroviral vectors. Hum Gene Ther 13:867-79
Barao, Isabel; Vaz, Fatima; Almeida-Porada, Graca et al. (2002) Human natural killer cell development in a xenogeneic culture system. Br J Haematol 118:885-92
Tran, N D; Porada, C D; Almeida-Porada, G et al. (2001) Induction of stable prenatal tolerance to beta-galactosidase by in utero gene transfer into preimmune sheep fetuses. Blood 97:3417-23
Lewis, I D; Almeida-Porada, G; Du, J et al. (2001) Umbilical cord blood cells capable of engrafting in primary, secondary, and tertiary xenogeneic hosts are preserved after ex vivo culture in a noncontact system. Blood 97:3441-9
Almeida-Porada, G; Porada, C; Zanjani, E D (2001) Adult stem cell plasticity and methods of detection. Rev Clin Exp Hematol 5:26-41
Almeida-Porada, G; Porada, C D; Tran, N et al. (2000) Cotransplantation of human stromal cell progenitors into preimmune fetal sheep results in early appearance of human donor cells in circulation and boosts cell levels in bone marrow at later time points after transplantation. Blood 95:3620-7
Almeida-Porada, G; Flake, A W; Glimp, H A et al. (1999) Cotransplantation of stroma results in enhancement of engraftment and early expression of donor hematopoietic stem cells in utero. Exp Hematol 27:1569-75

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