November 8, 1998. Copyright 1998. Graphic News. All rights reserved.

Cells that could revolutionise medicine

LONDON, November 8, Graphic News: IMAGINE a laboratory where cells can be grown to produce any kind of tissue or replace any organ in the human body, from brain cells to treat AlzheimerÕs disease to muscle cells to repair a damaged heart Ð and be transplanted to any recipient without risk of rejection.
Biologists say a major scientific breakthrough could realise this vision in just a few yearsÕ time.
The milestone Ð thought by many to be a Holy Grail of biology Ð is the development of a technique to pluck out and grow Ôhuman embryonic stem cellsÕ (hES cells), the raw material for every tissue and organ in the body.
Now two research groups have published papers on the technique in separate journals just days apart. The findings are published in the current issues of the research journal Science and in the Proceedings of the National Academy of Sciences.
One group, from the University of Wisconsin, took the hES cells from fertilised eggs left over from test-tube fertility treatments and donated by the parents. The embryos were just a few days old, at a stage of development known as a blastocyst. This is a ball of about 150 cells which would normally become embedded in the wall of the uterus and develop into a foetus.
Within the ball of cells they identified the stem cells and found a way to grow them in a culture dish.
A second team at Johns Hopkins University in Baltimore did a similar experiment with embryonic Ôgerm cellsÕ Ð sperm and egg cells from aborted foetuses Ð and also grew them into hES cells.
Thomas Okarma, vice president of research and development at Californian biotechnology company Geron, which privately funded the research, explains that most cells have a specific function. There are liver cells, skin cells, brain cells and so on. Once they have taken on this function, a process known as differentiation, there is no going back.
But hES cells, a very small percentage of cells in an embryo, are not tissue specific and can grow to be any kind of tissue.
When tissue specific stem cells divide there are structures at the ends of the chromosomes, known as telomeres, which shorten slightly. As a consequence the cells age prematurely and stop dividing. The hES cells respond to the enzyme telomerase which stops the shortening process. This enables the cells to replicate indefinitely, creating an immortal cell line which can give rise to every cell type found in the body.
Professor John Gearhart, who led the Johns Hopkins team says, ÔThe potential of these unique, versatile cells for human biologic studies and medicine is enormous.Õ 
The ability to grow these cells in the laboratory will immediately benefit scientists studying human growth and development.
Biologist James A. Thomson, who led the UW research team, says, ÔWithin five years doctors may be able to use infusions of these cells to replace damaged tissues, instead of having to wait until scientists figure out how to grow an entire organ in the laboratory.Õ
Eventually they may be used as tissue donors such as pancreatic islet cells for people with diabetes or neurons for treatment of ParkinsonÕs disease, stroke or even spinal cord injury.
Both groups say that the growing cells appear to be genetically normal, and have not been damaged by the process.
The controversial research did not receive federal funding because of U.S. laws against experimenting on human embryos. Some groups object that the cells came from aborted foetuses and others that Geron, who will hold the key patents, should not control something so important for improving human health care.

/ENDS
Sources: Geron, Science, Proceedings of the National Academy of Sciences, UPI, Reuters