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What are stem
cells?
Most of our body parts have a constant turnover of cells due
to normal wear and tear. For example, skin cells, blood cells,
and cells in the mouth, food and windpipe all have a turnover.
The body generates new cells to replace these worn-out cells
through special reservoir cells known as stem cells, which
have an unlimited potential for regeneration. These cells
are called adult stem cells, and have two main functions.
Firstly, they help maintain the cell population by replacing
worn-out cells with new ones to ensure survival of a tissue,
organ, or an organism. Secondly, they serve to repair tissues
or organs where cells are lost due to injury or disease.
Different
types of stem cells
There are two types of stem cells – adult and embryonic. Adult
stem cells are committed to generate cells for their respective
organs or tissues. They are already specialized according
to their area and location and their scope is limited: skin
cells will only
become skin, cartilage will only become cartilage.
Embryonic stem cells, however, are undifferentiated cells
that can develop into any type of adult cell in an appropriate
environment or ‘culture.’ Embryonic stem cell research and
its clinical application is still a subject of intense study
the world over. L V Prasad Eye Institute does NOT do any embryonic
stem cell work.
The
need for stem cell transplantation
Sometimes due to injury, infection or disease in any part
of the body, the stem cells may become excessively damaged,
leading to an unusual or unrealistic demand for regeneration
of new cells. In such cases the body may not be able to generate
enough cells required to repair the damaged organ. This leads
to a deficiency of cells and consequent dysfunction of the
affected tissue or organ.
Until recently organ failure was treated with direct transplantation
of donated organs and tissues, like liver transplants, kidney
transplants, and heart transplants. The understanding of the
functioning of stem cells made it possible to treat certain
diseases by culturing these cells in the laboratory. However,
the only areas where stem cells are probably being used clinically
in human beings, globally, are blood disorders (bone marrow
transplant) and eye diseases.
The stem cell transplantation technique involves ‘culturing’
or growing cells in the laboratory by taking a small bit of
tissue, and then transplanting them into the area deficient
in stem cells.
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