Two scientists from different generations won the Nobel Prize in
medicine on October 8 for the groundbreaking discovery that cells in the
body can be reprogrammed to become completely different kinds,
potentially opening the door to growing customized tissues for
treatments.
Sir John Bertrand Gurdon (JBG),
Fellow of Royal Society (born 2 October 1933) is a British
developmental biologist. He is best known for his pioneering research in
nuclear transplantation and cloning.
Prof Gurdon used a gut sample to clone
frogs and Prof Yamanaka altered genes to reprogramme cells. The Nobel
committee said they had "revolutionised" science. When a sperm
fertilises an egg there is just one type of cell. It multiplies and some
of the resulting cells become specialised to create all the tissues of
the body including nerve and bone and skin. It had been though to be a
one-way process - once a cell had become specialised it could not change
its fate. In 1962, John Gurdon showed that the genetic information
inside a cell taken from the intestines of a frog contained all the
information need to create a whole new frog. He took the genetic
information and placed it inside a frog egg. The resulting clone
developed into a normal tadpole. The technique would eventually give
rise to Dolly the sheep, the first cloned mammal.
Shinya Yamanaka,
born September 4, 1962 in Higashiosaka) is a Japanese physician and
adult stem cell researcher. He serves as the director of Center for iPS
Cell Research and Application and a professor at the Institute for
Frontier Medical Sciences at Kyoto University, as a senior investigator
at the UCSF-affiliated J. David Gladstone Institutes in San Francisco,
California, and as a professor of anatomy at University of California,
San Francisco (UCSF). Dr. Yamanaka is also the current President of the
International Society for Stem Cell Research (ISSCR).
Shinya Yamanaka used a different
approach on stem cell research. Rather than transferring the genetic
information into an egg, he reset it. He added four genes to skin cells
which transformed them into stem cells, which in turn could become
specialised cells. The Nobel committee said the discovery had
"revolutionized our understanding of how cells and organisms develop.
"The discoveries of Gurdon and Yamanaka have shown that specialized
cells can turn back the developmental clock under certain circumstances.
Stem cells
Most adult
cells in the body have a particular purpose which cannot be changed.
For instance, a liver cell is developed to perform specific functions,
and cannot be transformed to suddenly take on the role of a heart cell.
Stem cells are different. They are still at an early stage of
development, and retain the potential to turn into many different types
of cell.
When a stem cell divides, each new cell has the potential to either remain a stem cell or become another type of cell with a more specialised function. Scientists believe it should be possible to harness this ability to turn stem cells into a super "repair kit" for the body. Theoretically, it should be possible to use stem cells to generate healthy tissue to replace that either damaged by trauma, or compromised by disease.
Among the conditions which scientists believe may eventually be treated by stem cell therapy are Parkinson's disease, Alzheimer's disease, heart disease, stroke, arthritis, diabetes, burns and spinal cord damage. Stem cells may also provide a useful way to test the effects of experimental drugs. It is also hoped that studying stem cells will provide vital clues about how the tissues of the body develop, and how disease takes hold.
Scientists believe the most useful stem cells come from the tissue of embyros. This is because they are pluripotent - they have the ability to become virtually any type of cell within the body. Stem cells are also found within adult organs. They have not taken on a final role, and have the potential to become any of the major specialised cell types within that organ. Their role is to maintain the organ in a healthy state by repairing any damage it suffers. It is thought their potential to become other types of cell is more limited than that of embryonic stem cells. But there is evidence that they are still relatively "plastic".
Controversy
Campaigners are vehemently opposed to the use of embryonic stem cells. These cells are typically taken from lab-created embryos that are just four or five days old, and are little more than a microscopic ball of cells. However, opponents argue that all embryos, whether created in the lab or not, have the potential to go on to become a fully fledged human, and as such it is morally wrong to experiment on them. They strongly advocate the use of stem cells from adult tissue.
Some researchers fear that it is possible that stem cell therapy could unwittingly pass viruses and other disease causing agents to people who receive cell transplants. Some research has also raised the possibility that stem cells may turn cancerous. Work also still needs to be done to refine the new technique.
Recent winners of Nobel Prize in Medicine
2012- Briton’s John Gurdon and Japan’s Shinya
Yamanaka for their discovery that mature cells can be reprogrammed into
immature cells that can be turned into all tissues of the body, a
finding that revolutionised understanding of how cells and organisms
develop.
2011- American Bruce Beutler and
French researcher Jules Hoffmann for their discoveries concerning the
activation of innate immunity, sharing it with Canadian-born Ralph
Steinman for his discovery of the dendritic cell and its role in
adaptive immunity.
2010 - British researcher Robert Edwards for the development of in vitro fertilization.
2009
- Americans Elizabeth Blackburn, Carol Greider and Jack Szostak for
their discovery of how chromosomes are protected by telomeres and the
enzyme telomerase, research that has implications for cancer and aging
research.
2008 - Harald zur Hausen and
Francoise Barre-Sinoussi and Luc Montagnier for discoveries of human
papilloma viruses causing cervical cancer and the discovery of human
immunodeficiency virus.
2007- Mario R.
Capecchi and Oliver Smithies of the United States and Martin J. Evans of
the United Kingdom, for their discoveries leading to a powerful
technique for manipulating mouse genes.
2006 - Andrew Z. Fire and Craig C. Mello of the United States for their work in controlling the flow of genetic information.
2005
- Barry J. Marshall and Robin Warren of Australia for their work in how
the bacterium Helicobacter pylori plays a role in gastritis and peptic
ulcer disease.
2004 - Richard Axel and Linda
B. Buck, both of the United States, for their work in studying odorant
receptors and the organisation of the olfactory system in human beings.
2003
- Paul C. Lauterbur, United States, and Sir Peter Mansfield, Britain,
for discoveries in magnetic resonance imaging, a technique that reveals
the brain and inner organs in breathtaking detail.
2002-
Sydney Brenner and John E. Sulston, Britain, and H. Robert Horvitz,
United States, for discoveries concerning how genes regulate organ
development and a process of programmed cell death.
2001-
Leland H. Hartwell, United States, R. Timothy Hunt and Sir Paul M.
Nurse, Britain, for the discovery of key regulators of the process that
lets cells divide, which is expected to lead to new cancer treatments.
2000
- Arvid Carlsson, Sweden, Paul Greengard and Eric R. Kandel, United
States, for research on how brain cells transmit signals to each other,
thus increasing understanding on how the brain functions and how
neurological and psychiatric disorders may be treated better.
1999
- Guenter Blobel, United States, for protein research that shed new
light on diseases, including cystic fibrosis and early development of
kidney stones.
1998 - Robert F. Furchgott,
Louis J. Ignarro and Ferid Murad, United States, for the discovery of
properties of nitric oxide, a common air pollutant but also a lifesaver
because of its capacity to dilate blood vessels.
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