Stem-Cell Therapies Make A Comeback

(image from derazzii's fotos: Stem Cell Research Gone Bad)

A phenomenon that just two years ago was seen as the death knell for many stem-cell therapies is now being investigated as a possible fast track into medical use. It all centres around encouraging stem cells from bone marrow to fuse with cells elsewhere in the body.
Our bodies contain populations of "adult" stem cells that divide and replenish tissues that would otherwise wear out. Medical interest in using these cells for therapies exploded after early experiments suggested that under some circumstances, they can colonise other tissues and "transdifferentiate" to replenish the cells in their new home. This opened up the possibility of using the plentiful stem cells found in bone marrow - known as haematopoietic stem cells or HSCs - to treat a wide variety of diseases.
But those hopes were deflated in 2003 when it became clear that rather than undergoing a transformation, migrant HSCs were fusing with cells in the other tissues (New Scientist, 5 April 2003, p 17). "At first people said it was 'merely' fusion," says Helen Blau of Stanford University in California. "They couldn't imagine that it was a useful thing. But maybe this is something the body uses for repair."
Also that year, Markus Grompe and his team at the Oregon Health and Science University in Portland studied mice with a disease called tyrosinemia type 1, which is caused by the lack of an enzyme that breaks down the amino acid tyrosine. Its symptoms include jaundice, lethargy and cirrhosis of the liver, but the mice can be cured by infusing their livers with HSCs from healthy mice. Grompe's team showed that this is a result of the HSCs fusing with liver cells, and providing the gene for the missing enzyme.
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