Stem Cells

Stem Cells

This article deals with ‘Stem Cells  – UPSC.’ This is part of our series on ‘Science and Technology’ which is important pillar of GS-3 syllabus . For more articles , you can click here

What are Stem cells

Class of undifferentiated cells that are able to differentiate into specialized cell types.

Stem cell should be:

  • Undifferentiated cells having ability to divide & differentiate itself into specialized cells.
  • Importantly should have the capability of self-renewal, i.e. reproduce itself.
Stem cell differentiation

Type of Stem Cells

1.Embryonic Stem cells

  • Derived from the embryo
    • Humans reproduce sexually i.e. need a sperm and an 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 capable of producing an organism
    • Hence, embryonic cells have ability to differentiate itself into different specialized cells.
  • They are Totipotent ie can become any specialised cell &’organ

2. Non embryonic /somatic/ adult stem cells

  • Exist throughout the body after embryonic development. Found inside of different type of tissues  such as brain, bone marrow, blood , blood vessels , Skeletal muscles , skin & liver
  • Remain in a quiescent or non living state for years until activated by disease or tissue injury
  • 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 an 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

Potency of Stem Cells

  • Stem cells are categorized by their potential to differentiate into other types of cells.
  • Embryonic stem cells are the most potent since they must become all types of cell in the body.

1.Totipotent

  • Ability to differentiate into all possible cell types.
  • Examples are the zygote formed at egg fertilization and the first few cells that result from the division of the zygote.

2. Pluripotent

  • Ability to differentiate into almost all cell types.
  • Examples include embryonic stem cells and cells that are derived from the mesoderm, endoderm, and ectoderm germ layers that are formed in the beginning stages of embryonic stem cell differentiation.

3. Multipotent

  • the ability to differentiate into a closely related family of cells.
  • Examples include hematopoietic (adult) stem cells that can become red and white blood cells or platelets.

4. Unipotent

  • the ability to only produce cells of their own type, but have the property of self-renewal required to be labeled 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 right advocates view this as equivalent to murdering a child
  • It was also against the religions and was vehemently opposed especially in USA . Republican governments were totally against this as they are in favor of promoting christian ethics

Converting ordinary cell to Induced Pluripotent Stem Cell – Gurdon & Yamanaka

  • Single cell in the form of Zygote formed after fertilisation of egg and sperm differentiate to specialist cells like heart cells , liver cells, skin cells etc. Earlier it was thought that this natural process is irreversible
  • But  Gurdon  and Yamanaka identified the genes to make any cell pluripotent and also showed that cell can be programmed to any specific cell like Bone Marrow or heart cell
  • This solved the issue of killing of embryos to get Stem Cells
Stem Cells

Gist : Problems in using Stem Cells

  • Issue of Embryonic Stem Cells : Right to Life of Embryos + Christian sentiments
  • Efficacy of Stem Cell Therapy : iPSC’s doesn’t has 100% efficacy and in many cases reprogrammed cells can result into cancerous cells by rapid division
  • Inclusivity issue : Stem Cell therapy is very expensive and poor cant afford it. Hence, it is not inclusive .

What are the applications of Stem cells?

  • Stem Cells can cure several illnesses
    1. Parkinson’s disease [A degenerative disorder caused by cell death in brain – became very common in developed nations due to increase in Life expectancy]
    2. Alzheimer
    3. Cancer
    4. Spinal Cord Injury
    5. Treatment of Autism
    6. Blood related diseases (like Sickle Cell Anemia)
    7. Diabetes
    8. Heart and Arterial Related diseases
  • (Regenerative Medicine) Can be used in organ transplants : Using Stem cell, full fledged organ can be made  and since it is made from cells of person’s body, their rejection rate is almost nill.
  • Study how an organism develops from a single cell .

Stem Cell Therapy Status  in India

  • Western Countries have strict regulations and restrictions on use of Stem Cells but no such regulation was earlier present in India . Due to lack of regulation and cheap treatment, large number of terminally ill patients were coming to India for treatment.
  • April 2018 : Ministry of Health and Family Welfare has proposed to amend Drugs and Cosmetics Act, 1940 to bring Stem Cells and Stem Cell based products under legal regulation
    • Under the amendments, Stem Cells and products that are substantially altered will be treated as drugs and will have to seek 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  
  • MoUs
    • Indo – Japan Stem Cell Research Collaboration
    • India – UK Stem Cell Research
  • Research Centre : DBT Centre in Bangalore dedicated to Stem Cell Research (In-STEM)

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