Generally, human tissues have a limited capacity to regenerate. However, recent discoveries and progress on stem cell research and tissue engineering are promising prospects for tissue regeneration in the nearest future. Stem cell biology is one such field, offering hope for curing scourges like diabetes, Parkinson’s disease, neurological degeneration, and congenital heart disease, as well as bringing together many disciplines of cell and molecular biology. Stem cells are cells that haven’t differentiated yet and had the ability to divide and also have the potentiality to turn itself into various other types of cells, which can be useful for treating and understanding diseases. Thus, the 21st century is heralded as a century of cell biology, biomedicine, molecular medicine, and stem cells.
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Types of Stem Cells
Stem cells are the foundation for every organ and tissue of the body. There are different types of stem cells that come from different parts of the body, which can be used for different purposes. Mainly, there are three types of stem cells: Embryonic stem cells, Non-embryonic (adult) stem cells, and induced pluripotent stem cells.
1. Embryonic Stem Cells
Embryonic stem cells, as their name suggests, are derived from embryos. They are obtained from the inner cells of the mass of the blastocyst, a mainly hollow ball of cells that, in the human, forms three to five days after a sperm fertilizes an egg cell. Scientists extract the inner cell mass and grow these cells in special laboratory conditions and retain the properties of the embryonic stem cells. Embryonic stem cells are known as pluripotent stem cells. They can give rise to any other cells in the body.
2. Non-Embryonic (Adult) Stem Cells
Adult stem cells are more specialized than embryonic stem cells. They come from the developed tissues and organs of the body. These stem cells can repair and replace the damaged tissues only in the area where they are found. Hematopoietic stem cells are the example of adult stem cells. They are used in bone marrow transplants to cure certain types of cancer. Adult cells can’t differentiate into many other cells as embryonic stem cells.
3. Induced Pluripotent Stem Cells (iPSCs)
Induced pluripotent stem cells (iPSCs) are stem cells that are engineered in the lab by converting adult stem cells into embryonic stem cells. They can produce new cells for any organ or tissue. IPS cells are a useful tool for scientists for drug development and modeling of diseases, and they hope to use them in transplantation medicine. Furthermore, tissues derived from IPS cells will be the nearly ideal match for cell donor and have the least possibility of rejection by the immune system. Research is underway to find a way to produce IPS cells safely.
Cord blood stem cells and amniotic fluid stem cells are also types of stem cells. Cord blood stem cells are harvested from the umbilical cord after childbirth, and stem cells are also found in the amniotic fluid.
Technological Advances Through Stem Cell Research
Stem cell research has made high progress with promising applications.
a. Stem Cell Treatment and Therapy
A very large amount of research is going on globally on stem cell treatment and therapy. The most widely used and accepted stem cell treatment is the transplantation of the blood stem cells to treat diseases and improve the condition of the immune system of the body and also to restore the blood cells after the treatments of specific cancers. Skin stem cells have also been used to grow skin grafts for patients who have burnt the large area of the body. Recently, stem cell therapy has been used for cornea regeneration in the eye. Many clinical trials are going on using pluripotent cells to achieve success for the eradication of the diseases.
b. Drug Development and Disease Modeling
Stem cell technology has the potential to understand human disease and also transform the process of drug discovery by providing more relevant biological models for the selection of drug candidates. A lot of diseases are complex and caused by mutations in several genes at the same time. These are difficult to model even with genome engineering techniques. However, iPSCs help to deal with these situations. iPSCs have huge implications for drug development and disease modeling. For example, researchers have generated brain cells from iPSCs made from skin samples of patients with neurological disorders such as Down’s syndrome or Parkinson’s disease. These lab-grown brain cells show signs of the patients’ diseases. This has implications for understanding how the diseases happen – researchers can watch the process in a dish – and for searching and testing new drugs.
c. Corneal Regeneration
Researchers have found that tissue stem cells taken from an area of the eye called limbus can be used to repair the damage to the cornea. This can help those patients who have undamaged limbal stem cells in one of their eyes. This treatment is safe and effective in clinical trials.
Many other experiments have been going on stem cell technology. There is a high expectation of stem cell research but not yet high delivery of stem cell treatments.
Challenges of Stem Cell Technology
Despite an enormous amount of research being undertaken, there are still some disappointing treatments available to patients. There is still a lot to learn about stem cells. However, their current applications as treatments are sometimes exaggerated by the media and other parties who fully doesn’t it and also by the clinics looking to capitalize on the hype by selling treatment to chronically ill or seriously injured patients. Stem cell controversy is also one of the challenges of stem cell technologies. It is the consideration of the ethics of research involving the development, use, and destruction of human embryos. Most commonly, this controversy focuses on embryonic stem cells. People against ESC believe that human embryo also has the rights as human beings and shouldn’t be used for the clinical trials
Undeniably, stem cell researchers are making great advances in understanding normal development, figuring out what goes wrong in disease, and developing and testing potential treatments to help patients. They still have much to learn about how stem cells work in the body and their capacity for healing the diseases in the body.