Scholarly Interest:
Our laboratory, which
in the past has used embryonic stem cells to create genetic models of
disturbed fatty acid metabolism, has now switched to studying the nature
and therapeutic applicability of preimplantation stem cells. We have
found that when certain stem cells from very early rat embryos are transplanted
into adult rats, subsequently transplanted hearts that otherwise would
be rejected are accepted. This graft tolerance may be rooted in an unusual
combination of immunosuppressive and hematopoietic differentiation potentials
of the stem cells. Our results raise questions on the identity of early
rat stem cells and their relationship to stem cells of other species.
We are therefore studying the molecular identity and lineage determination
of preimplantation rat embryo stem cells in comparison with better-known
mouse stem cells, and we try to reconstitute the transplantation phenomenon
in the mouse. The comparison has already revealed significant rat-mouse
differences that indicate a greater diversity among preimplantation
stem cells than previously thought. Understanding them will be important
not just when working with rodents, but should allow deeper insight
into the nature of preimplantation stem cells in general, which ultimately
is important for therapeutic applications in both animals and humans.
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