Stem cell are the basis for cell proliferation and expansion of multicellular organism. These cells have the ability to reproduce and self-renew which can differentiate into a variety of different cell types. The first stage of the stem cell existence in the life is in embryonic blastocyst period, and this type of cell remains in the tissues throughout life to differentiate into various cells of body whenever cells were under damage.
Stem cells are classified into different types such as pluripotent, multipotent, oligopotent and unipotent, bases on their ability to proliferate and differentiate.
Totipotent cells: The cells that are capable of self-renewal which not only can make all the differentiated cells of the body, but also will make other rare cells such as embryonic cells and placental tissue.
- A flat-worm type, due to the presence of specific stem cells in their bodies, is capable to split into hundreds parts, and each part will creates a complete and healthy worm which are the same as pluripotent stem cells.
Pluripotent stem cells: In addition of self-healing (the ability to produce their own cells), this type of cells can produce different types of differentiated cells in the body. They can create all of 200 types of human cells, both basic and non-basic.
- The pluripotent stem cells have biomedical applications because they are able to survive and proliferate indefinitely in the laboratory.
Multipotent stem cells: multipotent stem cells are cells that have the self-renew capability and to develop into multiple specialized cell types present in a specific tissue or organ. Most adult stem cells are multipotent stem cells.
- Hematopoietic stem cells, for example, are multiple-strand stem cells, since they can make different types of differentiated cells. Some of the differentiated cells produced by hematopoietic stem cells include: red blood cells, neutrophils, basophils, monocytes and ….
Unipotent stem cells: the unipotent stem cell is the concept that one stem cell has the ability to differentiate into only one cell type.
- For example, Spermatogonial Stem Cells (Spermatogonial Stem Cells) are unipotent stem cells, because they can only make a differentiated cell type (such as sperm).
- There are also stem cells called “satellite cells”, because they can only make muscle cells.
Embryonic stem cells:
These cells derived from the inner cell mass of a blastocyst, 3 to 5 days after the formation of the embryonic, and can be converted to various types of cells in the body of an organism. These cells grow and proliferate indefinitely under suitable conditions. The embryonic stem cells are potent, which means that they can form various types of cell lines. These cells are a valuable source for cure of diseases.
Adult stem cells:
These cells have evolved from embryonic stem cells and are capable of transforming into a variety of different cell types of tissue or organs. These cells are responsible to replacement of lost cells in young tissues.
These cells are only able to transform into the cell of the tissues which they are located. Liver stem cells, for example, can convert to liver cells and cannot convert to heart cells.
Cord Stem Cells:
The umbilical cord is a birthplace product that is discarded after the baby’s birth. While umbilical cord blood is rich in stem cells. These cells, like hematopoietic stem cells derived from bone marrow, have a high ability to treat blood diseases and cancers.
Induced pluripotent cells:
This cells that can be generated in the laboratory like embryonic stem cells. These cells are converted into pluripotent cells by inserting 4 genes in unipotent cells such as fibroblast. In this case, researchers found that they can produce pluripotent cells from patient’s cells which can differentiate into a variety of cells. This technique is especially useful for laboratory studies, but many tests have to be conducted to evaluate efficacy in order to be used as a cell or tissue source for medical treatment.
Stem cell value:
Nowadays, scientists are doing a lot of research around of the world by increasing our understanding of the human body and finding effective ways to treat new diseases.
Since the understanding of the proper tissues and organs as well as their performance has a surprising effect on better and more effective diagnosis of diseases and injuries, on the one hand, recent medications do not contribute to the complete improvement of the diseases that have been promoted, the cell therapy has given new hope to future generations.
Scientists are reviewing how stem cells are used to produce tissue and transplant them to tissues damaged by disease, aging and any injuries, in the pursuit of desired outcomes. Also, investigating and finding ways to spontaneously stimulate human stem cells, has studied a wide range of diseases to repair damaged tissues or to prevent further damage to these tissues.
Stem cell research has provided a great deal of medical treatment, but scientists are still looking for more information about stem cells and how to apply them to medical science.
One of the promising paths in scientific discoveries is the transformation of scientific knowledge into medical treatment, this process will reach to results when scientists provide the necessary assurance for providing effective and safe treatment in therapeutic approach. Since studies on animal models may not have the same results on human models, the use of these studies will cause problems in treatment. Therefore, scientists are trying to prove their claims about the effective and safe use of stem cells in the treatment of diseases, by matching the results of animal and human studies.
The basis and components of all living organisms are cells, and scientists must consider the structure of the body to understand the causes of each diseases. Therefore, scientists with understanding and testing of scientific principals in laboratories, provide important medical discoveries.
By finding a scientific problem and their answers, scientists will find the best methods by carefully examining all probabilities. This is possible through observation and experimentation. This method can be used in all branches of science, but in cellular science, by considering all of components and tissues of the cell’s body, strong steps can be taken to achieve therapeutic goals.
- Proposed a question
- Perform initial research
- Compilation and adjustment of hypothesis
- Doing experimental tests
- Data and information analysis
Scientific method as a set of steps, ideas and information which lead to achieve valuable results during the process of trying and error. In addition, by publishing the methods and results of their studies in magazines, they share their achievements and discoveries to people around of the world.
Clinical research is based on the findings and scientific research of the patient and helps develop therapeutic methods. This research has great importance on the treatment, disease prevention, disease’s control and the possibility of effective intervention. Therefore, by applying to research in animal models and their adaptation to the results of human studies, scientists will achieve to quantitative and qualitative upgrades.
Clinical trials solutions:
A clinical trial usually begins with few number of volunteers and focuses on risk of assessment and possible complications. In this method, after review of the risks and effects, gradually increased the number of participants which lead to examine the effectiveness of the treatment.
- Common points in clinical trial
Clinical trials are actually research studies that are seeking to investigate methods and medicine treatments or strategies which are safe and effective for humans. The rules of clinical trials are different in each country. But there are some common criteria, including respect to participant rights, credible scientific evidence, and extensive oversight in accordance with established rules and regulations.
- At the moment, very few of the stem cell-based treatments have been safe and effective.
The list of treated diseases by cell therapy is still short, which means that with observations, the widespread cells used by hematopoietic stem cells have been used to treat hematologic diseases, immune system disorders, or circulatory system regeneration, or even some types of cancers. However, some treatments have been made in the skin, bones and eyes, and this method has been accepted as a safe and effective way by the medical community.
- The treatment has not yet been proven.
When there is no effective treatment for an illness, it is easy to understand the use of new therapies that have not yet been shown to have therapeutic effect. Unfortunately, despite extensive studies on stem cells, cell therapy cannot be ignored. On the other hand, due to the high cost of the treatment, most insurance companies cannot cover the cost of the treatment.
- Different types of stem cells in the body serve different purposes
Scientists are reviewing the specific stem cells of the tissue and their various roles in treatment, and have reached specific capabilities for each of these cells. Stem cells from a specific tissue can only be converted to the same tissue cells. For example, bone marrow stem cells play a role in the regeneration of blood vessels or nervous cells just play role in brain or spinal cord repair.
- The inadequate stem cells efficacy on various diseases
Stem cells which derived from specific tissue has just capability to produce specialized cell types of that tissue. Therefore, this type of cells have ability to affects diseases that are related to the specific tissue and can regenerate cells to repair it.
In this case, scientists have learned to create specific stem cells that are called pluripotent, fetal, and induced pluripotent stem cells under laboratory conditions or through the use of multi-stage processes. These cells have a high potential for the formation of various types of cells in the body, which have great hope for new therapeutic strategies. Although embryonic and induced pluripotent stem cells are not a good choice for direct injection into the patient due to the high risk of carcinogenesis and tumor formation.
- Autologous stem cells (own stem cells) are not completely without risk for your body.
As we know, immune cells do not attack their own cells and this is the basis for using these cells to treat patients who call an autologous transplant. However, it should be acknowledged that cell transplantation will not be safe after the isolated and cultivated processes. Some of the risks which we can point that are in the following:
As the cells are under cultivated process in the laboratory, they are exposed to pathogens such as bacteria, viruses and fungi. In addition, they may be loss the control system due to some manipulation process which happened on them or they will causes problems after injection because lack of belonging to a specific tissue.