Monday, November 12, 2007

Understanding Stem Cell Research -1

On 8th November, 2007 the Indian Council of Medical Research (ICMR) and the Department of Biotechnology that has finalized extensive guidelines for embryonic stem cell research after five years of discussion submitted them to the Union health ministry. These guidelines have been prepared for public debate. It envisages two committees: a National Apex Committee for Stem Cell Research and Therapy and an Institutional Committee for Stem Cell Research and Therapy.

Earlier there was a “Ethical guidelines for Biomedical Research on HumanSubjects” issued by the ICMR in October, 2000. In 2004, ICMR had prepared a Draft Guidelines for Stem Cell Research/Regulation in India that has noted sources of stem cells as follows:

i) Adult stem cell : Derived from peripheral blood, tissue or bone marrow

ii) Cord Blood Cell : Derived from placenta

iii) Embryonal stem cells: Derived either from blastocysts or foetal tissues

Meanwhile, on 5 November, 2007, Kapil Sibal, Union Minister for Science & Technology laid the foundation stone for nation’s first Clinical Research Facility (CRF) for Stem Cells and Regenerative Medicine (CRF) on a five-acre site at Uppal in Hyderabad by the Centre for Cellular and Molecular Biology (CCMB) along with Nizam’s Institute of Medical Sciences. The Minister revealed that in aspects of embryonic and adult stem cell research more than 40 institutions and hospitals in country are involved and a Bill is planned to be introduced to provide incentives or 30 per cent of license fee as royalty to scientists to encourage them for research.

It is noteworthy that so far human cloning is banned everywhere. The UN General Assembly adopted the United Nations Declaration on Human Cloning, by which Member States were called on to adopt all measures necessary to prohibit all forms of human cloning inasmuch as they are incompatible with human dignity and the protection of human life on 8th March, 2005 by a vote of 84 in favour to 34 against, with 37 abstentions. World opinion is divided on the possibilities of therapeutic cloning. India is on the side of the partial ban.

It is significant to note that India had voted against the UN Declaration. However, the immediate issue facing the Indian policymakers is embryonic stem cell research that includes harvesting stem cells from embryos in order to treat diseases, such as Alzheimer’s, or diabetes, or even cancer, destroy, in the present state of technology, the embryos from which the cells are taken.Stem cells are obtained from foetuses, embryos, the umbilical cord and bone marrow.

Countries representing about 3.5 billion people have a permissive or flexible policy on human embryonic stem cell research and all have banned human reproductive cloning.

Can the logic of scientific progress be barred by concerns that are social and ethical in the matter of stem cell research?

Is it not always possible that a banned activity will go underground?

Should possibility of abuse prevent research leading to healing and greater knowledge?

Note: The Draft Guidelines for Stem Cell Research/Regulation in India were prepared by the Expert Group Members and Drafting Committee as mentioned below:

Expert Group Members
1. Dr. P.N. Tandon, New Delhi Chairman
2. Dr. S.S. Agarwal, ACTREC, Mumbai
3. Dr. N.K. Mehra, AIIMS, New Delhi
4. Dr. Dipika Mohanty, IIH, Mumbai
5. Dr. Y.N. Rao, DGHS, New Delhi
6. Ashwini Kumar, DCGI, New Delhi
7. Dr. Narayan Swamy, Dy. DCGI, New Delhi
8. Dr. Hari Gopal, DST, New Delhi
9. Dr. T.S. Rao, DBT, New Delhi
10. Dr. Alka Sharma, DBT, New Delhi
11. Dr. C.M. Habibullah, DCMC & Allied Hospitals, Hyderabad
12. Dr. U.V. Wagh, NCCS, Pune
13. Dr. Vinod Raina, AIIMS, New Delhi
14. Dr. Vineeta Salvi, KEM, Mumbai
15. Dr. Satish Kumar, CCMB, Hyderabad
16. Dr. G.R. Chandak, CCMB, Hyderabad
17. Dr. Ambika Nanu, AIIMS, New Delhi
18. Dr. S.G.A. Rao, Reliance, Mumbai

Drafting Committee

1. Dr. A.N. Bhisey, CRI, Mumbai Chairman
2. Dr. U.V. Wagh, NCCS, Pune
3. Dr. D. Mohanty, IIH, Mumbai
4. Dr. P.B. Seshagiri, IISc, Bangalore
5. Dr. M.G. Deo, Moving Academy, Pune
6. Dr. V. Salvi, KEM, Mumbai
7. Dr. S.S. Agarwal, ACTREC, Mumbai
8. Dr. K. Ghosh, IIH, Mumbai
9. Dr. V. Muthuswamy, ICMR, New Delhi Member Secretary

1 comment:

Gopal Krishna said...

What are stem cells?

Stem cells build tissue when and where it's needed.

Without stem cells, wounds would never heal, your skin and blood could not continually renew themselves, fertilized eggs would not grow into babies, and babies would not grow into adults. Stem cells are quite unlike the specialized, or differentiated, cells in your body — such as the nerve cells, muscle cells and blood cells that enable you to function. In contrast, they are the body's silent reserves. At any given moment, many of the stem cells in your body won't be doing very much. They will only spring into action when you need either to produce more stem cells or make more of other, specialized types of cells. And they're not just found in people. All multicellular organisms, from plants to humans, need stem cells.

Usually, when a stem cell divides into two, one daughter cell goes on to make a more specialized type of cell, or even gives rise to several different cell types. The other daughter cell remains a stem cell, ready to produce more stem cells when they are needed. Only stem cells have this versatility, although some fully specialized cells, such as liver cells, can divide to give more cells exactly like themselves.

A fertilized egg is the ultimate stem cell, as it is the source of every type of cell in the body, from oxygen-carrying red blood cells to electricity-conducting nerve cells and throbbing heart muscle cells. But of course this doesn't happen all at once. As the fertilized egg divides to make an embryo, cells become specialized gradually.

Within three to six days after a human egg is fertilized, it has grown into a ball of a few hundred cells called a blastocyst. Within this ball lie a small number of cells that will go on to develop into the embryo. Scientists have learned to extract these stem cells from a thickening in the blastocyst called the inner cell mass and to grow them in the laboratory. These are known as embryonic stem cells or ES cells, and they have the potential to produce all the cell types in the human body. When a blastocyst implants in a woman's uterus, the cells of the inner cell mass will keep on dividing and differentiating into the earliest types of embryonic cells. Human ES cells in culture are not created from eggs that have been fertilized inside a woman's body. They come from the inner cell masses of 'spare' blastocysts that have been created in the laboratory as part of in vitro fertilization (IVF) programmes.

Less than three weeks after a human egg has been fertilized, these most flexible of stem cells have disappeared and embryonic cells become gradually more restricted in their potential. Instead of dividing to make one more specialized daughter cell and a back-up all-purpose stem cell, later embryonic cells are more likely to make two types of more differentiated cells when they divide. At this stage, the embryo's cells have 'committed' to become one of three general types of tissue that each has distinct types of stem cells. Many of these persist into adult life. As embryonic development continues, cells become even more specialized, forming recognizable tissues such as heart, muscle and blood.

In adults, dozens of stem-cell types have been described; more remain to be discovered. These stem cells are called tissue-specific as they will normally only replace one particular tissue. They are also sometimes called adult stem cells. The best understood are the stem cells that grow new blood cells, those that renew the skin, those that renew the gut lining, and those that can grow new skeletal muscles. Stem cells in the bone marrow make blood cells and have been used therapeutically for years. These are the cells that make it possible for a bone marrow transplant to renew a person's complete blood system.

Scientists across the world are trying to figure out exactly what these stem cells are capable of becoming in the lab and in the body; right now, however, tissue-specific stem cells appear to be specialists, quite good at making a few types of cells. Stem cells found in bone marrow naturally make new red blood cells and new white blood cells, for instance, but not new brain cells, at least, not robustly. Stem cells occurring in the brain make new neurons plus the cells that support them, but they don't seem to make muscle cells.

How can stem cells advance medicine?

Stem cells could help medicine in three general ways: cell-based therapies, drug discovery and basic knowledge. Cell therapies would use stem cells, or cells grown from stem cells, to replace or rejuvenate damaged tissue.

Scientists also want to use stem cells to understand disease and find drugs that might treat it.

Embryonic stem cells could be used to make more specialized tissues that have been lost to disease and injury. For tissues that are constantly replaced, like blood and skin, stem cells would probably be replaced directly. Researchers are also exploring ways to use stem cells to treat diabetes, Parkinson's disease, spinal cord injury, heart disease and vision and hearing loss, among others.

As of April 2007, however, no therapies using cells derived from embryonic stem cells have been tested in humans. The efficacy of stem cell therapies depends on the introduced cells arriving where they are needed and either replacing or rejuvenating damaged cells. They should not contain undifferentiated embryonic stem cells, and either the cells, the patient or both should be treated so that the patient's immune system will not attack the transplants.

As an alternative to cell therapies, some researchers are looking for traditional drugs that would prompt adult stem cells to come out of hiding and replace damaged tissues. In one early study, rats with a strokelike injury had more control over their movement after being treated with a compound that stimulates stem cells in the brain.

Embryonic stem cells could be grown into more specialized cells for screening potential drugs. Cultures of cancer cells are already used for screening cancer drugs, and growing embryonic stem cells into heart, liver or nerve cells could be useful for testing drugs that affect those organs. Ideally, the human cells could be custom-made to represent the genetic diversity and traits typical of people who suffer from the disease being studied. Right now, potential drug molecules are tested first in mice and rats, but results of these animal tests do not always correlate with what happens in humans. Drugs that poison a human liver, for example, might do no harm to a rat's.

Many scientists think that testing pollutants and potential drugs on cells grown from human embryonic stem cells could be more accurate than current tests. This could mean that fewer animals would be killed for research and also make research faster and cheaper. However, if such experiments are to work, scientists will have to develop techniques to make sure that the cells and culture conditions remain constant; otherwise, differences between experiments could be due to factors other than the drug candidates being tested.