Stem Cells: The Revolutionary Cure
Types of Stem Cells
Embryonic | Adult | Induced Pluripotent | Cancer
Embryonic Stem Cells
Pluoripotent
Embryonic stem cells originate from embryos: the developing human organism 2-8 weeks after conception. Embryonic stem cells are pluripotent meaning they are able to form into one of the over 200 different types of cells but they cannot become placenta cells. These rare cells exist from the first 5 days of early fetus development generally, but can be grown from a laboratory. They can be obtained from leftover embryos that are willingly donated by patients from fertility clinics. As these cells and induced-pluripotent stem cells are both pluripotent, both have the potential of becoming any type of stem cell. Furthermore, these eggs are often fertilized in vitro fertilization clinics rather a woman’s body. Through a process called cell culture, human embryonic stem cells are generated by transferring cells while in the preimplantation stage onto a laboratory dish that contains culture medium, a nutrient broth. Today, the cells would just divide and spread over the surface of the dish, whereas before, cell culturing was much more difficult as a layer called feeder layer was the source of nutrients; which resulted in a risk of viruses or macromolecules in the mouse cells to be transmitted into the human ones. Once the cells end up crowding the plate, they would then be extracted gently and relocated onto fresh culture plates. For many months, these cells are subcultured many times, and once finished, the original cells yield millions of embryonic stem cells. The stem cells that have continued to multiply for about six months or so without differentiating hare pluripotent and disposable.
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Adult Stem Cells
Multipotent
On the other hand, "somatic" stem cells, or "adult" stem cells are thought to be differentiated and are able to generate many of the cell types of its specific organ or tissue including teeth, heart, liver, skin, bone marrow, brain, blood vessels, etc. Adult stem cells are tissue-specific, meaning they are solely committed to becoming one of the cell types present in their particular organ or tissue. For instance, adult blood-forming stem cells in the bone marrow can give rise to red and white cells of the blood system, not able to transform into other types of cells: liver cells, brain cells, etc.
A prominent example of adult stem cells are cord blood cells that are donated right after birth; they are a form of adult blood-forming stem cells. Adult stem cells' main purpose is to repair damaged tissues or organs in an organism’s body by replacing the old, diseased cells. This is a great discovery in the world of medicine as scientists realize it is possible to use types of adult stem cells like hematopoietic, bone marrow stromal, mesenchymal stem cells, for instance, to generate the brain's three major cell types—astrocytes and oligodendrocytes, which are non-neuronal cells, and neurons, which are nerve cells. This may be helpful in cases of cardiac-muscle issues, type B Diabetes, or various cancer diagnoses. Adult stem cells are also unable to be grown indefinitely from a laboratory and resemble stem cells from the placenta and umbilical cord of newborn infants more than embryonic stem cells taking in the fact that both are tissue-specific. (Image 3, Text 3)
Induced Pluoripotent Stem Cells
Pluoripotent
Induced-pluripotent stem cells originate from adult stem cells and have been genetically modified by scientists to behave like embryonic stem cells, all adult cell types, from any tissue (usually blood or skin). This means to give powerful properties to adult stem cells that are tissue-specific and allow them to obtain the capacity to adapt to a different organ or tissue. This advancement in science has scientists very excited, considering the fact that the possibility of reprogramming adult stem cells into whichever origin needed is open, although induced-pluripotent stem cells (iPS cells) are still yet to be subjugated. They can be rooted from children or adults and are characterized as pluripotent.
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Cancer Stem Cells
Pluoripotent
Unlike the previous stem cells above, cancer stem cells are not positively revolutionary in today’s medicine. They can self-renew and breed cancer as the “seeds” of cancer, acting as the source of all cells making up the disease. Chemotherapy destroys the bulk of the tumor, leaving the cancer stem cells intact but do not regrow into new tissues or organs unlike normal stem cells. Another crucial implication is that cancer stem cells very often promote and give rise to metastases, when cancerous cells travel and infect one part of the body to another by spreading rapidly. This may allow them to act as a sort of reservoir for cancer cells resulting in a relapse after surgery, radiation, or chemotherapy has eliminated all noticeable, observable indications of a cancer procreating. Many recent studies have shown that these cancer stem cells, however, are closely related to normal stem cells and share many behaviors. They follow many rules seen by daughter cells in regular, healthy tissues, acting similar to a caricature of normal cells; displaying similar features in a distorted way. Taking this into account, it may be possible to use this information to attack cancer stem cells and the malignant cells they produce.
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