Talk of policy has dominated talk of science for those interested in embryonic stem cell science. But research is continuing, and the advances are making clear why embryonic stem cells are such an important scientific and medical resource.
Fraud in a South Korean laboratory shoots down a high-flying scientist and nicks the country’s pride. A nasty Congressional battle over loosening federal restrictions on embryonic stem cell (ESC) research ends with President George W. Bush’s first veto. In California, a protracted lawsuit stalls the state’s voter-approved program for funding stem cell work, prompting Governor Arnold Schwarzenegger to offer an emergency loan.
Stem cells have hit the front page again and again this year—for the wrong reasons, researchers say. The ethical, political, and financial commotion has overshadowed the field’s scientific progress, which researchers say is accelerating. "The literature is burgeoning—it’s sometimes hard to keep up," says Ian Duncan (University of Wisconsin, Madison, WI). Although the United States’ regulatory environment and limited involvement in ESC research slows progress the world over, "I’m very pleased with the pace we’re going at," says Alan Trounson (Monash University, Melbourne, Australia). He heads the Monash Immunology and Stem Cell Laboratory, where 120 scientists are prodding stem cells to specialize into kidney, liver, blood, and other cell types.
As reviewed recently by Trounson (2006), it was Thomson et al. (1998) who first reported the successful isolation of human ESCs from blastocysts. Derivation without the need for feeder cells was more recent (Klimanskaya et al., 2005), and refinement of culture conditions has continued (Hoffman and Carpenter, 2005). There are now many markers for these human ESCs, and they can be transfected and differentiated into ectodermal lineages (e.g., oligodendrocytes for possible myelination; dopaminergic neurons potentially for Parkinsonism; and motor neurons for possible spinal cord repair), mesodermal lineages (cardiomyocytes and hematopoietic derivatives), and, with more difficulty, endodermal lineages (pancreatic islet–like cells and hepatocyte-like cells). Several disease-specific lines of human ESCs have been developed, thus generating models for diseases such as Fanconi anemia-A and cystic fibrosis.
