BY HILARY POTKEWITZ
Despite extensive debate about stem cells and their use, there has been considerable confusion about what they are exactly, and what they do.
But following California's approval of billions of dollars in state spending on stem cell research via Proposition 71 in the fall election, researchers, including those at UC Irvine, are primed to boost efforts to develop cures based on this misunderstood science.
Stem cells are the building blocks of tissues and organs in the body. The unspecified cells can become any tissue, muscle, organ or bone in the body, given the right conditions. Stem cells can be frozen and, once thawed, will continue to renew themselves.
The term "stem cell" relates to the cells' special kind of division, said Dr. Peter Bryant, professor of developmental and cell biology at UCI.
"One product of the division remains the original stem cell, and the other product goes on to become something else , differentiated cell division," he said.
In other words, stem cells can be maintained and different cell types budded off , like clippings of one plant that could grow into different plants if their environment were changed.
Stem cell research, which goes as far back as the 1950s, involves human and animal stem cells. Mice and worm cells have been analyzed in great detail, and scientists are trying to determine to what extent human stem cells can be manipulated.
Human embryonic stem cells weren't isolated until the late 1990s.
The excitement and promise of stem cell research lies in the hope that these cells can be harnessed to regenerate damaged organs or help cure certain diseases.
"There are some definite targets," said Dr. Phil Schwartz, director of the Human Embryonic Stem Cell Culture Training Course at Children's Hospital of Orange County Research Institute. "Like diabetes, heart disease, the real killers. But which one we'll reach first is really up in the air right now."
There are two types of stem cells: adult and embryonic. The adult variety doesn't necessarily have to come from grown-ups; they're just the cells that have already been programmed to create particular organs or tissues: blood cells, heart tissue, liver or muscle cells, for example. Adult stem cells are present in newborn babies and adults, especially in tissues that need to rejuvenate themselves frequently. Therapies created with adult stem cells already are in use to treat diseases such as leukemia and lymphoma.
Embryonic stem cells only are present in the very early stages after fertilization. They are part of a ball of cells formed as the egg divides, called a blastocyst.
"Those cells are so immature that they still have the potential to form any type of tissue," Schwartz said.
Embryonic mice stem cells can divide continuously in a petri dish, and they retain the ability to generate any cell type when exposed to the right environment. Scientists are studying these cells in humans to determine if the same can be done.
Adult stem cells can be obtained by various means , from living donors, tissue removed during surgery, the umbilical cord of a newborn baby, an aborted fetus, or even a cadaver within two days of death.
But human embryonic stem cells can only come from very early embryos grown in cultured petri dishes at in vitro fertilization clinics.
When the stem cells are removed from the embryos, the embryos lose their viability. Extraction of stem cells from embryos has created the most controversy.
Legalities Of Research
Research on adult and embryonic stem cells is legal. But because embryonic stem cell research kills the donor embryo, there has been opposition from several fronts.
Many religious organizations oppose the idea of creating human embryos solely for research purposes.
President Bush in 2001 set up criteria for which types of embryonic stem cell research can be federally funded, restricting funding to the 60 cell lines then in existence. Only 23 of those lines were healthy enough to be used in research.
Proposition 71 provides $3 billion in state funds for stem cell research.
How the funds will be used will be determined by the California Institute for Regenerative Medicine's 29-member committee.
Two UCI researchers have been named to the panel: Susan Bryant, a researcher in limb regeneration and dean of UCI's School of Biological Sciences, and Oswald Steward, director of the university's Irvine-Reeve Research Center.
Hilary Potkewitz writes for the
Los Angeles Business Journal.