Breakthrough by NUS scientists: safe stem cells

By using only human cells and no animal input - a world first - they eliminate risk of transmitting animal diseases to people

August 5, 2002, The Straits Times
By Salma Khalik
HEALTH CORRESPONDENT

EMBRYONIC stem (ES) cells can now be used safely in patients as Singapore scientists have eliminated any risk of them transmitting animal diseases to people.

Professor Ariff Bongso has succeeded in growing ES cells with only human cells and absolutely no animal input. The breakthrough is a big leap for medical science for it means that ES cells can now be used safely in people.

ES Cell International, an Australian-based company partly-owned by the Singapore Government, which represents the Singapore researchers' interest in this, filed a worldwide patent for the new method in May.

The ground-breaking achievement by the National University of Singapore (NUS) team will also be published in Nature Biotechnology, a prestigious journal on biotechnology research, next month. But an online version of the report was released this morning.

Prof Bongso, 56, said the US Food and Drug Administration (FDA) was delighted with the work. 'They would never have allowed the mouse ones for clinical use because of the worry of diseases,' he said. Prof Bongso is optimistic that animal-free ES cells will become the 'gold standard'.

All 78 ES cell lines approved for research in the US today are grown using animal input - typically on mouse feeder layers with nutrients from cows and pigs. A cell line refers to replicating the original 30-40 cells taken from a five-day old embryo, to produce large quantities for research and clinical use.

Scientists hope that ES cells - master cells that can turn into any cell in the human body - will be the magic bullet to counter deadly or debilitating diseases like cancer, Alzheimer's or diabetes.

The NUS team have developed feeders, the base layer on which the cells are grown, using human muscle, skin and fallopian tube. The liquid nutrients are derived largely from human blood. And to be doubly safe, both the donors and the donated cells have been checked for diseases, including Aids.

By now, the new cell line has been successfully grown for more than 40 generations.

A major side benefit is the cells remain undifferentiated for nine days, instead of the seven days when grown on mouse feeders. Cells would differentiate into any of the more than 200 cells found in a human body beyond such a period, and are useless for research.

Prof Bongso explained: 'The extra two days is of tremendous benefit as it scales up the numbers.' Each generation on human feeders produce about four times the number of usable cells.