Stem cells

Why in news:

Researchers are prospecting the use of stem cell technology for the treatment of COVID-19 patients.

What are Stem cells?

• Stem cells are undifferentiated cells that are able to differentiate and transform into any type of cells of the body when and where needed. It means they have the ability to develop into many different cell types, from muscle cells to brain cells.
• When a stem cell divides, each new cell which is formed has the potential to either remain a stem cell or become another type of cell which can have more specialised function.
• Types of stem cells:
  • Stem cells are divided into two main forms: 
    • Embryonic stem cells: These cells come from unused embryos resulting from an in vitro fertilization procedure and that are donated to science. These embryonic stem cells are pluripotent, meaning that they can turn into more than one type of cell like nerves cell, heart muscle cell etc.
    • Adult stem cells: They are undifferentiated cells found among differentiated cells in a tissue or organ. They are also called somatic cells, i.e cells of a living organism other than the reproductive cells. The main role of adult stem cells in a living organism is to maintain and repair the tissue in which they are found. There are two types of adult stem cells. One type comes from fully developed tissues, like the brain, skin, and bone marrow. They are more likely to generate only certain types of cells. The second type is induced pluripotent stem cells. These are adult stem cells that have been manipulated in a laboratory to take on the pluripotent characteristics of embryonic stem cells.
• Sources for stem cells: - Embryos, bone morrow, peripheral blood tissue, umbilical cord, placenta, aborted foetal tissue are the sources of stem cells.

What is stem cell therapy?

• The usage of stem cells to cure or treat a disease or repair the injured tissue is defined as stem cell therapy. Due to their tremendous potential to prevent and to treat various health conditions, investigations are continuously being done to explore the maximum advantage from this field.
• They are of two types:
  • Allogeneic stem cell therapy: Patient receives the stem cells donated by another individual.
  • Autologous stem cell therapy: Patient receives stem cells from his/her own body. Autologous stem cell therapy is better than allogeneic stem cell therapy as they pose minimum risk of immune rejection. They start the healing process immediately in a natural way.

Guidelines related to Stem cells in India:

• In 2002, Indian Council of Medical Research had released Draft Guidelines for Stem Cell Research/Regulation.
• In 2007, Department of Biotechnology had released Guidelines for Stem Cell Research and Therapy.
• In 2013, National Guidelines for Stem Cell Research were released. These guidelines help the clinicians and scientists working in the field to conduct research in scientific and ethical manner.
• In 2017, National Guidelines for Stem Cell Research were released. According to these guidelines, only bone marrow stem cell transplant for blood disorders is permitted.

Benefit of Stem cell technology:

• Regenerative therapy: Stem cells are key to regenerative medicine, as they can be guided into becoming specific cells that can be used to regenerate and repair diseased or damaged tissues in people. This can help people suffering with Leukemia, spinal cord injuries, type 1 diabetes, Parkinson's disease, burns, cancer, osteoarthritis etc.
• Increase understanding of how diseases occur: By watching stem cells mature into cells in bones, heart muscle, nerves, and other organs and tissue, researchers and doctors may better understand how diseases and conditions develop.
• Minimal invasion: Stem cell therapy is a minimally invasive, non-surgical procedure and has negligible risks of rejection and infection. Also, the post-procedure recovery time is very small compared to a normal surgery.
• Effectively test new drugs: Before using investigational drugs in people, researchers can use stem cells programmed into tissue-specific cells to test the drugs for safety and quality. 
• Safety net for the future: Stems cells especially those from the umbilical cord blood can be stored for long durations. Also, the stem cells from a baby is useful for the whole family. Hence, with the development in technology, the preserved stem cells can be of great medical use in the future.

Challenges:

• Nascent field: Over the last few decades, the field of stem cell-based therapeutics has only moved from basic science to preclinical and early stage clinical trials. In India as well as globally, only blood stem cells from bone marrow to treat blood cancers and different blood disorders are permitted. The clinical use in any other disease or use of any stem cells other than these is still in research stage.
• Limitations of adult cells: Adults have very small quantity of stem cells. The cells of a particular origin would generate cells only of that type, like brain cells would generate only brain cells and so on. Also, they are more likely to contain abnormalities due to environmental hazards, such as toxins, or from errors acquired by the cells during replication.
• Limitations of embryonic cells: So far, the rejection rates for embryonic stem cells are high. If the cells used in the therapy are embryonic, then the cells will not be from the same human body and there are chances of rejection.
• Unknown side-effects: Like any other new technology, it is completely unknown what the long-term effects such cellular level interference can create.
• Ethical concern: The use of the stem cells for research involves the destruction of blastocysts that are formed from the laboratory fertilization of the human egg. Hence, several questions and issues have been raised about the ethics of embryonic stem cell research.
• Cost of treatment: The cost of stem cell therapy and associated procedures are on the higher side.

Conclusion

• Stem cell therapy has the vast potential in the field of therapeutics such as skin replacement, bone marrow transplant, organ development and tissue replacement.
• A number of projects have been supported by the Department of Biotechnology in India in collaboration with Japan. Further push, in the form of investments, infrastructure and trained human resource are essential for developing India into a competitive force in the field of stem cell medicine.
• Today, six of the seven leading causes of death in the world are due to non-communicable diseases. Regenerative medicine may be our best hope to solve the non-communicable diseases of our time.
• There are concerns about the safety and utility of stem cell therapies and having no regulation would only bring bad name to the industry and increase distrust. Hence, the future developments must be strictly evidence-based and in a well-regulated environment.

Practice Question

Q. Stem cells are considered to be one of the most transformative medical innovation in the century. What are stem cells? Discuss their advantages and challenges involved in their application.