Embryonic Stem Cells As an Alternate Marrow Donor Source

Abstract

A single embryonic stem cell (ESC) line can be repetitively cryopreserved, thawed, expanded, and differentiated into various cellular components serving as a potentially renewable and well-characterized stem cell source. Therefore, we determined whether ESCs could be used to reconstitute marrow and blood in major histocompatibility complex (MHC)-mismatched mice. To induce differentiation toward hematopoietic stem cells (HSCs) in vitro, ESCs were cultured in methylcellulose with stem cell factor, interleukin (IL)-3, and IL-6. ESC-derived, cytokine-induced HSCs (c-kit+/CD45+) were isolated by flow cytometry and injected either intra bone marrow or intravenously into lethally irradiated MHC-mismatched recipient mice. From 2 wk to 6 mo after injection, the peripheral blood demonstrated increasing ESC-derived mononuclear cells that included donor-derived T and B lymphocytes, monocytes, and granulocytes without clinical or histologic evidence of graft-versus-host disease (GVHD). Mixed lymphocyte culture assays demonstrated T cell tolerance to both recipient and donor but intact third party proliferative responses and interferon γ production. ESCs might be used as a renewable alternate marrow donor source that reconstitutes hematopoiesis with intact immune responsiveness without GVHD despite crossing MHC barriers.

A ubiquitous chromatin opening element prevents transgene silencing in pluripotent stem cells and their differentiated progeny

“…As with other pluripotent stem cell-based gene therapy strategies targeting the hematopoietic system, the myeloprotective approach investigated here ultimately will require the generation of HSCs with in vivo long-term reconstituting potential (LT-HSCs), an aim that despite promising early data [48] has so far not been established as a reproducible procedure. Nevertheless, technological progress in recent years has considerably facilitated the in vitro generation of hematopoietic progenitor cells of various lineage commitments [49][50][51], and with foreseeable further advancement in this field, the generation of bona fide LT-HSCs from pluripotent cell sources appears as an achievable goal.…”

Treatment of severe autoimmune disease by stem-cell transplantation

“…Successful tolerance protocols would overcome alloresponses to donor islet alloantigens and could prevent recurrent autoimmunity in the donor islets, as suggested by mixed-chimaerism studies in NOD mice with advanced diabetes 39 . Either combined HSC and islets from deceased donors or the combined transplantation of embryonic stem cell 58 or adult stem-cellderived islets and HSC could ultimately be used to achieve tolerance and cure of type 1 diabetes. In addition, promising approaches to xenotolerance induction, including HCT 59 , might ultimately allow the use of xenotransplants (grafts from donors of other species such as pigs) that could provide a solution to the shortage of allogeneic islets.…”

Progress and prospects: gene transfer into embryonic stem cells

“…For example, rat or mouse ES-derived hematopoietic cells can survive engraftment in a xenogenic or fully mismatched environment without immunosuppression. 55,66,67 This property may be due to the embryonic nature of ESCs, and seems to be conserved in hESCs. Li et al 68 have shown that hESCs and their derivatives can evade both in vivo xenogenic and in vitro allogeneic immune responses despite normal levels of MHCI.…”

“…In addition, purifying cells can avoid complications due to the potential contamination of the graft with residual undifferentiated ESCs. For instance, in a study by Burt et al, 55 mESC-derived engraftable hematopoietic progenitors were shown to express c-kit + CD45 + cell-surface markers. The incidence of teratomas at the site of injection occurred only when whole, unsorted, cell populations were transplanted to irradiated mice, and not when fractionated c-kit + CD45 + were used.…”