Stem cells are the body’s raw material. They give rise to all other cells of the various organs, with specialized functions. In some cases, they also have the ability to regenerate and / or repair damaged tissue.
They appear in the human being still in the embryonic phase, and even after birth some organs still keep within themselves a small portion of stem cells , responsible for the constant renewal of that specific organ. The researchers believe that stem cell- based therapies could one day be used to treat devastating illnesses, such as paralysis and Alzheimer’s disease , for example.
Stem cells have two special characteristics: (1) they can reproduce by duplication, generating two equal cells and (2) they can differentiate, that is, transform into tissue cells of their respective organs.
Once divided, the daughter cells become new stem cells (self-renewal) or specialized cells (differentiation) with a more specific function, identical to that of the organs where they were housed. Thus, for example, stem cells hematopoietic located in bone marrow red, is responsible for generating all cells of the blood . The same happens with the cells brain, muscle, heart, bone, etc. No other cell in the body has the natural ability to generate new types of cells .
What types of stem cells are there?
As for the possibility of generating new tissues, they can be:
- Totipotent: cells that have the ability to generate all types of cells and tissues in the body. They are the cells originating from a newly formed embryo ( zygote ), disappearing a few days after fertilization .
- Pluripotent: they have the ability to generate cellsfrom the three embryonic leaflets ( ectoderm , mesoderm and endoderm ), that is, they are capable of generating any tissue , except the trophoblast ( extraembryonic cells ).
- Multipotent: slightly more differentiated, they have the ability to generate a limited number of specialized cells.
- Unipotent: able to differentiate over only one lineage. They are found in adult organs or tissues.
The researchers also found perinatal stem cells in amniotic fluid and cord blood . These stem cells also have the ability to transform into specialized cells . Further studies are needed of stem cells from the amniotic fluid to understand its potential for transformation.
Find out more about ” Degenerative diseases “, ” Alzheimer ‘s disease ” and ” In vitro fertilization “.
The use of stem cells in medicine
Medical interests in stem cells are many. Among others, (1) they can increase the understanding of how diseases occur; (2) generate healthy cells to replace diseased cells (regenerative treatment), useful mainly in degenerative diseases ; (3) testing new drugs for safety and effectiveness.
Many of the possibilities, however, are still in the realm of expectation. The only stem cells currently used in the treatment of diseases are hematopoietic stem cells, which form blood cells . In fact, every kind of cell blood begins as a stem cell from bone marrow . These cells are used in procedures such as transplantation bone marrow . This helps people with blood cancer to create new cells after their own hematopoietic stem cells have been killed by radiation therapyand / or chemotherapy . They can also be used to treat anemia , Fanconi , a blood disorder that causes failure in bone marrow .
The researchers think that, in the future, stem cells could help health in many ways, through many new treatments, being used to create new tissues. For example, they think the day will come when healthcare professionals will be able to grow healthy heart muscle cells in the laboratory and transplant them into hearts damaged by chronic heart disease. Among other revolutionary treatments can target diseases such as diabetes type 1 lesions in the spinal cord , Alzheimer’s disease and rheumatoid arthritis . New drugs can also be tested incells produced from pluripotent stem cells.
However, stem cells need much more study before their use can be widespread. Scientists need to learn more about how embryonic stem cells develop because it will help them understand how to control the type of cells created from them. Because these cells are difficult to grow in the laboratory, researchers are looking for ways to improve the process of obtaining them. Another challenge to be overcome is that the embryonic stem cells available today are likely to be rejected by the body. But scientists also face challenges when using stem cellspluripotent adults. There is a greater chance that they may contain DNA problems.
Either way, the future is promising!
The ethical problem of using stem cells
The stem cell embryonic embryos are obtained at the initial stage which is actually a group of cells that forms when the egg is fertilized by sperm , a fertilization in vitro . As embryonic stem cells are extracted from human embryos, several questions have been raised about the ethics of research and the use of stem cells . In almost all the most advanced places, the National Institutes of Health have created guidelines for stem cell research . The guidelines define how these cellscan be used in research and generally include recommendations for the donation of embryonic stem cells.