This article deals with ‘Stem Cells – UPSC.’ This is part of our series on ‘Science and Technology, which is an important pillar of the GS-3 syllabus. For more articles, you can click here.
What are Stem cells?
The stem cells are the class of undifferentiated cells that have the ability to differentiate into specialized cell types.
Stem cells should be:
- Undifferentiated cells having the ability to divide & differentiate themselves into specialized cells
- It has the capability of self-renewal, i.e. reproducing itself
Type of Stem Cells
1. Embryonic Stem Cells
- They are derived from the embryo.
- Humans reproduce sexually, i.e. need sperm and eggs.
- The sperm fuses with the egg to form a fused product called Zygote. This cell divides itself to form different organs like eyes, heart, lungs etc., i.e. one cell is capable of producing an organism.
- Hence, embryonic cells have the ability to differentiate themselves into different specialized cells.
- They are Totipotent, i.e. can become any specialized cell & organ.
2. Non-embryonic /Somatic/ Adult Stem Cells
- Adult Stem Cells exist throughout the body after embryonic development. They are found inside the different tissues such as the brain, bone marrow, blood, blood vessels, Skeletal muscles, skin & liver.
- They remain in a quiescent or non-living state for years until activated by disease or tissue injury.
- They can divide or self-renew indefinitely, enabling them to generate a range of cell types from the originating organ or even regenerate the entire organ.
- Generally, adult stem cells are limited in their ability to differentiate based on their tissue of origin.
- Adult stem cells are rare in mature tissues. Hence isolating these cells from adult tissue is challenging, and methods to expand their numbers in cell culture have not yet been worked out.
3. Induced Pluripotent Stem Cells (iPSCs)
- Adult cells that have been genetically reprogrammed to an embryonic stem cell-like state.
The potency of Stem Cells
- Stem cells are categorized on the basis of their potential to differentiate into other types of cells.
- Embryonic stem cells are the most potent since they can become all types of cells in the body.
- Totipotent cells can differentiate into all cell types.
- Examples: Zygote formed at egg fertilization, and the first few cells from the division of the Zygote
- Pluripotent Stem Cells are the stem cells that can differentiate into almost all cell types.
- Examples include cells from the beginning stages of the embryo.
- Multipotent Stem Cells can differentiate into a closely related family of cells.
- Examples include hematopoietic (adult) stem cells that can become red and white blood cells or platelets.
- Unipotent stem cells have the ability to produce cells of their own type only. But they have the property of self-renewal required to be labelled a stem cell.
- Examples include (adult) muscle/Somatic stem cells.
Controversy regarding Embryonic Stem Cells
- Stem cells are generally derived from embryos, as adult stem cells are difficult to extract. But human rights advocates view this as equivalent to murdering a child.
- It was also against the conservative Christian beliefs and was vehemently opposed, especially in the USA. Republican governments were totally against this as they favoured promoting Christian ethics.
Converting ordinary cells to Induced Pluripotent Stem Cells – Gurdon & Yamanaka
- A single cell in the form of a Zygote formed after fertilization of egg and sperm differentiates to specialist cells like heart cells, liver cells, skin cells etc. Earlier, it was thought that this natural process was irreversible.
- But Gurdon and Yamanaka identified the genes to make any cell pluripotent and also showed that cells can be programmed to any specific cell like Bone Marrow or heart cell.
- It solved the issue of killing embryos to get Stem Cells.
Gist: Problems in using Stem Cells
- Ethical concerns: Ethical dilemmas in using stem cells involve the destruction of human embryos to obtain stem cells. In the USA, Christian values against the destruction of embryos stymied the research in stem cells.
- Efficacy of Stem Cell Therapy: iPSCs don’t have 100% efficacy, and in many cases, reprogrammed cells can result in cancerous cells by rapid division
- Inclusivity issue: Stem Cell therapy is costly, and the poor can’t afford it. Hence, it is not inclusive.
What are the applications of Stem cells?
- Stem Cells can cure several illnesses
- Parkinson’s disease [A degenerative disorder caused by cell death in the brain – became prevalent in developed nations due to an increase in life expectancy]
- Spinal Cord Injury
- Treatment of Autism
- Blood-related diseases (like Sickle Cell Anaemia)
- Heart and Arterial Related diseases
- Regenerative Medicine: Stem cells can be used in organ transplants. A full-fledged organ can be produced using Stem Cells. Since it is made from cells of a person’s body, the rejection rate of such organs is almost nil.
- Research: It helps to understand the basic biology of how living things work.
- Treatment of HIV: Scientists have shown that Stem cells can be used to treat HIV, which is considered a miracle in medicine. In 2022, a women in the US was treated of HIV using Stem Cell Transplant.
Stem Cell Therapy Status in India
- Western Countries have strict regulations and restrictions on the use of Stem Cells, but no such regulation was earlier present in India. Due to a lack of regulations and cheap treatment, many terminally ill patients were coming to India for treatment.
- In 2018, the Ministry of Health and Family Welfare proposed to amend the Drugs and Cosmetics Act, 1940, to bring Stem Cell and Stem Cell-based products under legal regulation. Under the amendments, Stem Cells and substantially altered products will be treated as drugs. Therefore, they will have to seek the regulator’s approval (Drug Controller General of India) before being marketed.
- Various ICMR Guidelines
- ICMR’s National Guideline for Stem Cell Research in 2017.
- Stem Cell Use Ethical Guidelines by ICMR
- Indo– Japan Stem Cell Research Collaboration
- India – UK Stem Cell Research
- Research Centre: DBT Centre in Bangalore is dedicated to Stem Cell Research (In-STEM).