Stem cell is a cell whose job in the body is not yet determined (they are unspecialized).Every single cell in the body stems from this type of cell.Hence the name stem cell.Stem cells have the remarkable potential to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.
Self - renewal (ability to go through numerous cycles of cell division while maintaining undifferentiated state) and Potency (capacity to differentiate into specialized cell types) are the unique properties of stem cells.
why are they important?
Stem cells are important for living organisms for many reasons. In the 3- to 5-day-old embryo, called a blastocyst, the inner cells give rise to the entire body of the organism, including all of the many specialized cell types and organs such as the heart, lung, skin, sperm, eggs and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are lost through normal wear and tear, injury, or disease.
Given their unique regenerative abilities, stem cells esp. embryonic stem cells could be used to replace any part of the body damaged by accident or illness. It could lead to cures for such recalcitrant diseases as Parkinson's, Alzheimer's and diabetes. Some scientists believe the cells might eventually allow those who are paralyzed to walk again. However, much work remains to be done in the laboratory and the clinic to understand how to use these cells for cell-based therapies to treat disease, which is also referred to as regenerative or reparative medicine.
Two broad types of mammalian stem cells are :
1.Embryonic stem cells
2.Adult stem cells
Embryonic stem cells are derived from embryos that develop from eggs that have been fertilized in vitro.Adult stem cells are undifferentiated cells, found throughout the body after embryonic development, that multiply by cell division to replenish dying cells and regenerate damaged tissues. Adult stem cells are also known as somatic stem cells.
Similarities and differences between Embryonic and Adult stem cells
Human embryonic and adult stem cells each have advantages and disadvantages regarding potential use for cell-based regenerative therapies. Of course, adult and embryonic stem cells differ in the number and type of differentiated cells types they can become. Embryonic stem cells can become all cell types of the body because they are pluripotent. Adult stem cells are generally limited to differentiating into different cell types of their tissue of origin(multipotent stem cells). However, some evidence suggests that adult stem cell plasticity may exist, increasing the number of cell types a given adult stem cell can become.
Large numbers of embryonic stem cells can be relatively easily grown in culture, while adult stem cells are rare in mature tissues and methods for expanding their numbers in cell culture have not yet been worked out. This is an important distinction, as large numbers of cells are needed for stem cell replacement therapies.
A potential advantage of using stem cells from an adult is that the patient's own cells could be expanded in culture and then reintroduced into the patient. The use of the patient's own adult stem cells would mean that the cells would not be rejected by the immune system. This represents a significant advantage as immune rejection is a difficult problem that can only be circumvented with immunosuppressive drugs.
Embryonic stem cells from a donor introduced into a patient could cause transplant rejection. However, whether the recipient would reject donor embryonic stem cells has not been determined in human experiments.
The unique potential contribution of human embryonic stem cells to therapies is a product of both their longevity and their capacity to produce a wide range of specialised cells in the laboratory. By contrast, adult stem cells that are grown in the laboratory appear to have much shorter lifespans than embryonic stem cells. This reduces their capacity to form new cell types. Stem cells can also be obtained from aborted fetuses and umbilical cord blood, but it is not clear whether the full range of cell types that are required for treatments could eventually be generated from these sources alone.
Stem cell controversy
The stem cell controversy is the ethical debate primarily concerning the creation, treatment, and destruction of human embryos incident to research involving embryonic stem cells. The status of the human embryo and human embryonic stem cell research is a controversial issue as, with the present state of technology, the creation of a human embryonic stem cell line requires the destruction of a human embryo. Stem cell debates have motivated and reinvigorated the pro-life movement, whose members are concerned with the rights and status of the embryo as an early-aged human life.They believe that embryonic stem cell research instrumentalizes and violates the sanctity of life and is tantamount to murder.The fundamental assertion of those who oppose embryonic stem cell research is the belief that human life is inviolable, combined with the belief that human life begins when a sperm cell fertilizes an egg cell to form a single cell.Crucial to the argument is the issue of whether the embryo/foetus is a “person”. The unborn child is not legally classified as a person, various courts also noted then that if the “personhood” of the preborn is established, then the case for the right to abortion collapses, because the foetus's right to life is then guaranteed by the constitutions.
Stem cell research in India
Stem Cell research in India is still in its infancy.Rules in India say embryos should not be generated for the sole purpose of obtaining stem cells. Only surplus or spare embryos can be used after obtaining informed consent of both spouses. Such collection of embryos should be done only from registered Assisted Reproductive Technique (ART) clinics.Though India is seen as a potential bio-tech powerhouse, lack of regulation has made stem cell research disorganized and unsafe. Now germ line that deals with research with genetic material like ova and sperm that is passed from parents to children would not be allowed. The ethical issue is the contention that this research, which seeks to identify genetic qualities, can be used to manipulate or change the gene. Similarly, genetic engineering and transfer of human blastocysts - a hollow ball of 100 cells reached after five days of embryonic development - into a human or non-human uterus will be illegal.Research or therapy using fetal stem cells/placenta is allowed. But, pregnancy termination cannot be sought for donating fetal tissue for possible financial or therapeutic benefits.
India has put in place the National Apex Committee for Stem Cell Research and Therapy (NAC-SCRT). This 12-member committee "reviews all controversial and ethically sensitive stem cell research proposals" and "oversee, monitor and make policies on stem cell use in India".
NAC-SCRT examines the scientific, technical, ethical, legal and social issues, involving each and every human embryonic stem cell research. All institutions and investigators carrying out research on human stem cells will have to be registered with NAC-SCRT through an Institutional Committee for Stem Cell Research and Therapy (IC-SCRT).
All research studies and clinical trials will have to have prior approval of IC-SCRT for permissive research and of NAC- SCRT for restricted research. All new stem lines will be created and all established cell lines from any source, imported or created in India will also have to be registered with IC - SCRT and NAC- SCRT.
Self - renewal (ability to go through numerous cycles of cell division while maintaining undifferentiated state) and Potency (capacity to differentiate into specialized cell types) are the unique properties of stem cells.
why are they important?
Stem cells are important for living organisms for many reasons. In the 3- to 5-day-old embryo, called a blastocyst, the inner cells give rise to the entire body of the organism, including all of the many specialized cell types and organs such as the heart, lung, skin, sperm, eggs and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are lost through normal wear and tear, injury, or disease.
Given their unique regenerative abilities, stem cells esp. embryonic stem cells could be used to replace any part of the body damaged by accident or illness. It could lead to cures for such recalcitrant diseases as Parkinson's, Alzheimer's and diabetes. Some scientists believe the cells might eventually allow those who are paralyzed to walk again. However, much work remains to be done in the laboratory and the clinic to understand how to use these cells for cell-based therapies to treat disease, which is also referred to as regenerative or reparative medicine.
Two broad types of mammalian stem cells are :
1.Embryonic stem cells
2.Adult stem cells
Embryonic stem cells are derived from embryos that develop from eggs that have been fertilized in vitro.Adult stem cells are undifferentiated cells, found throughout the body after embryonic development, that multiply by cell division to replenish dying cells and regenerate damaged tissues. Adult stem cells are also known as somatic stem cells.
Similarities and differences between Embryonic and Adult stem cells
Human embryonic and adult stem cells each have advantages and disadvantages regarding potential use for cell-based regenerative therapies. Of course, adult and embryonic stem cells differ in the number and type of differentiated cells types they can become. Embryonic stem cells can become all cell types of the body because they are pluripotent. Adult stem cells are generally limited to differentiating into different cell types of their tissue of origin(multipotent stem cells). However, some evidence suggests that adult stem cell plasticity may exist, increasing the number of cell types a given adult stem cell can become.
Large numbers of embryonic stem cells can be relatively easily grown in culture, while adult stem cells are rare in mature tissues and methods for expanding their numbers in cell culture have not yet been worked out. This is an important distinction, as large numbers of cells are needed for stem cell replacement therapies.
A potential advantage of using stem cells from an adult is that the patient's own cells could be expanded in culture and then reintroduced into the patient. The use of the patient's own adult stem cells would mean that the cells would not be rejected by the immune system. This represents a significant advantage as immune rejection is a difficult problem that can only be circumvented with immunosuppressive drugs.
Embryonic stem cells from a donor introduced into a patient could cause transplant rejection. However, whether the recipient would reject donor embryonic stem cells has not been determined in human experiments.
The unique potential contribution of human embryonic stem cells to therapies is a product of both their longevity and their capacity to produce a wide range of specialised cells in the laboratory. By contrast, adult stem cells that are grown in the laboratory appear to have much shorter lifespans than embryonic stem cells. This reduces their capacity to form new cell types. Stem cells can also be obtained from aborted fetuses and umbilical cord blood, but it is not clear whether the full range of cell types that are required for treatments could eventually be generated from these sources alone.
Stem cell controversy
The stem cell controversy is the ethical debate primarily concerning the creation, treatment, and destruction of human embryos incident to research involving embryonic stem cells. The status of the human embryo and human embryonic stem cell research is a controversial issue as, with the present state of technology, the creation of a human embryonic stem cell line requires the destruction of a human embryo. Stem cell debates have motivated and reinvigorated the pro-life movement, whose members are concerned with the rights and status of the embryo as an early-aged human life.They believe that embryonic stem cell research instrumentalizes and violates the sanctity of life and is tantamount to murder.The fundamental assertion of those who oppose embryonic stem cell research is the belief that human life is inviolable, combined with the belief that human life begins when a sperm cell fertilizes an egg cell to form a single cell.Crucial to the argument is the issue of whether the embryo/foetus is a “person”. The unborn child is not legally classified as a person, various courts also noted then that if the “personhood” of the preborn is established, then the case for the right to abortion collapses, because the foetus's right to life is then guaranteed by the constitutions.
Stem cell research in India
Stem Cell research in India is still in its infancy.Rules in India say embryos should not be generated for the sole purpose of obtaining stem cells. Only surplus or spare embryos can be used after obtaining informed consent of both spouses. Such collection of embryos should be done only from registered Assisted Reproductive Technique (ART) clinics.Though India is seen as a potential bio-tech powerhouse, lack of regulation has made stem cell research disorganized and unsafe. Now germ line that deals with research with genetic material like ova and sperm that is passed from parents to children would not be allowed. The ethical issue is the contention that this research, which seeks to identify genetic qualities, can be used to manipulate or change the gene. Similarly, genetic engineering and transfer of human blastocysts - a hollow ball of 100 cells reached after five days of embryonic development - into a human or non-human uterus will be illegal.Research or therapy using fetal stem cells/placenta is allowed. But, pregnancy termination cannot be sought for donating fetal tissue for possible financial or therapeutic benefits.
India has put in place the National Apex Committee for Stem Cell Research and Therapy (NAC-SCRT). This 12-member committee "reviews all controversial and ethically sensitive stem cell research proposals" and "oversee, monitor and make policies on stem cell use in India".
NAC-SCRT examines the scientific, technical, ethical, legal and social issues, involving each and every human embryonic stem cell research. All institutions and investigators carrying out research on human stem cells will have to be registered with NAC-SCRT through an Institutional Committee for Stem Cell Research and Therapy (IC-SCRT).
All research studies and clinical trials will have to have prior approval of IC-SCRT for permissive research and of NAC- SCRT for restricted research. All new stem lines will be created and all established cell lines from any source, imported or created in India will also have to be registered with IC - SCRT and NAC- SCRT.
