More than 100 centres around the world are spearheading research on stem cells. Conditions being investigated for the transplantation of cells generated from human embryonic stem cells, range from Parkinson’s disease, diabetes and spinal cord injury, to heart disease and hearing loss.

So great are expectations for the new therapies, that when patients heard that South Korean researchers were investigating stem cells and Parkinson’s and others diseases, more than 2,600 got in touch in one day, even though no trial date had been scheduled.

America and Canada have 50 leading centres, according to a report from the University of Minnesota, That compares with about 20 in the UK, some 25 in continental Europe, and 30 or so in the Asia-Pacific region.

America, despite strong lobbying against allowing and funding embryonic research, has also dominated published research.

In the past decade, there have been 530 publications reporting research involving cells derived from human embryos, according to Lord Winston, the fertility expert. Almost a third came from the US. In second place was Israel with 55, followed by the UK with 50. Other leading countries were Singapore (33), South Korea (33), China (32), Sweden (28), Australia (23), Canada (13) and Germany (11).

In America, researchers are looking at Parkinson’s disease, where scientists hope to replace the dopamine-producing nerve cells lost in the disease with neurones from stem cells. Scientists are also planning to use embryonic stem cells to generate neurones to replace those lost after a stroke. Muscular dystrophy is another disease target for US scientists.

Before his death, Christopher Reeve, the Superman actor paralysed in a horse riding accident, was one of the leading campaigners for stem-cell research and his view that it offered the best hope of a cure for paralysis, is proving well founded. Neurologists from Johns Hopkins University, Baltimore, who have had successes with research on animals, say in a report: “Restoration of functional motor units by embryonic stem cells is possible and represents a potential therapeutic strategy for patients with paralysis.”

Israel’s leading role in stem-cell research can be traced back to the 1960s. Leo Sachs, of the Weizmann Institute, was the first scientist to demonstrate the growth of stem cells in culture, and Israeli researchers were also key players in the landmark isolation of stem cells from human embryos in 1998. Israel has strengths both in embryonic stem cells and in adult stem-cell research. The country has about ten companies dealing with stem-cell related research.

China has earmarked stem-cell science for special investment, and clinical trials of cell-based therapies have been under way to treat brain injury, corneal disease and a number of neuro-degenerative illnesses.

Singapore can lay claim to being one of the pioneers of stem-cell research as Professor Ariff Bongso, an embryologist working at the National University of Singapore, was the first to isolate human embryonic stem cells. One of Singapore’s goals is to develop and manufacture cell-based therapies for treating a range of degenerative diseases including heart failure, eye disease and diabetes.

Much of the stem-cell research in Australia is directed through the Australian Stem Cell Centre, which brings together researchers from around the

country. The main areas of research are finding ways of regenerating damaged heart tissue, investigating stem-cell technologies for blood and bone-marrow regeneration, and the use of stem-cell therapies in lung diseases such as cystic fibrosis.

In 2000 a group of scientists from the Monash Institute of Medical Research first reported the development of nerve stem cells from embryonic stem cells.

In Sweden The Lund Centre for Stem Cell Biology and Cell Therapy, set up in 2003, is one of the biggest centres and focuses on stem-cell and developmental biology of the central nervous and blood systems.