The process avoids some of the ethical and technical obstacles involved in such research, according to the Johns Hopkins investigators.

The Johns Hopkins researchers' system involves the study of existing embryonic stem cell lines derived from in vitro fertilization methods, and so doesn't require generation of embryos through cloning, a technique recently reported by South Korean scientists.

In their report on the work in the June issue of the journal Blood, the Johns Hopkins team demonstrated a clear similarity between how human embryonic stem cells specialize into blood cells and how blood cells develop in human embryos.

"Our findings provide an unparalleled opportunity to study the basic questions of human development, like 'Where does blood come from?'" says Elias Zambidis, M.D., Ph.D., first author on the paper and an assistant professor of pediatrics and oncology in the Johns Hopkins School of Medicine.

Knowing the steps by which stem cells develop into blood cells are likely to help medical researchers figure out how to treat cancers of the blood, such as leukemia and lymphoma, Zambidis notes.

"More and more we're learning that the genes that turn on in the embryo to make blood stem cells are the same genes that go wrong in cancer," he says. "So if we understand what the important genes are and how they work, we might be able to develop and to target new cancer therapies more effectively."

Historically, scientists have worked on mouse and zebrafish models of embryological blood cell development, but ethical and technical barriers have stood in the way of an in-depth study of blood formation in human embryos. In the new work, Hopkins scientists and colleagues from the University of Pittsburgh School of Medicine
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Contact: Katherine Unger or Joanna Downer
jdowner1@jhmi.edu
410-614-5105
Johns Hopkins Medical Institutions
20-Jun-2005