Stem Cell Research

Stem Cell Research

Content:

• Stem Cell Research
• Characteristics of Stem Cell
• Historical Perspectives
• Classification of /stem Cells on the Basis of Potency
• Classification of Stem Cells on the basis of their Sources
• Applications of Stem Cells
• Potential Uses of Stem Cells
• Policy Challenge
• Ethical, Social, Political Debate
• Stem Cell Research Controversy
• Potential Impact on Health
• Guidelines for Stem Cell Research
• Conclusion
• Summary Page

STEM CELL RESEARCH

Stem cells are undifferentiated, or “blank,” cells. This means they’re capable of developing into cells that serve numerous functions in different parts of the body. Most cells in the body are differentiated cells. These cells can only serve a specific purpose in a particular organ. For example, red blood cells are specifically designed to carry oxygen through the blood.

All humans start out as only one cell. This cell is called a zygote, or a fertilized egg. The zygote divides into two cells, then four cells, and so on. Eventually, the cells begin to differentiate, taking on a certain function in a part of the body. This process is called differentiation.

Stem cells are cells that haven’t differentiated yet. They have the ability to divide and make an indefinite number of copies of themselves. Other cells in the body can only replicate a limited number of times before they begin to break down. When a stem cell divides, it can either remain a stem cell or turn into a differentiated cell, such as a muscle cell or a red blood cell.

CHARACTERISTICS OF STEM CELL                                                                   

• First, stem cells are generalized cells that have the capability of replenishing themselves through the process of cell division, which sometimes happens after a long phase of sluggishness.                                                                                                                                
• Secondly, under particular physiological or investigational situations, they can also be induced to turn them to organs or tissues. In various organs like bone marrow and the gut, stem cells divide regularly to repair and replace damaged and worn out tissues in the body. In other body organs like the heart and the pancreas, stem cells are known to divide only on particular conditions.

Historical perspectives                                                                           

The history of this cells’ research is for more than 5 decades. In the early 1950, there was the discovery that the bone marrow has at least two different types of stem cells. They include; hematopoietic stem cells which is applicable in the formation of all types of the body blood cells and bone marrow stromal stem cells, which are made by stem cells of non-hematopoietic in the bone marrow. They produce bone, fat, cartilages, fibrous connective tissue, and cells that usually support the bold formation process.

In the 1960s, the study of rats done by scientist discovered that there are two regions in the brain that have dividing cells that later become nerve cells. Despite this report, many scientists have a believe that an adult brain could be unable to produce new nerve cells.

 Later in 1990s, scientists believed that an adult brain do contain stem cells that have the power to produce the three main cells types brain.

In conclusion, embryonic stem cells are easily grown in culture. They are rare mature tissue, thus the process of separating them from an adult tissue is a challenge, and the means to expand these cells are yet to be innovated. This distinction is critical since the many cells are required to conduct stem cell replacement therapies.Through research, scientists have reasons to prove that those tissues, which results from the embryonic and those from adult stem cells usually, differ in the likelihood of rejection after transplantation is done. Stem cells and tissues of adults are currently seen to start a rejection after transplantation. This is because cells belonging to as patient are capable of being expanded in culture, coaxed to make them acquire a specialized type of cell, and latter reintroduced back to the patient. The use of tissues and adult stem cells whose origin is the patient’s own adult stem cells would suggest that the cells are prone to rejection by the immune system in the body. This shows a merit as rejection of immune an only be circumvented only by immunosuppressive drugs continuous administration although this drugs also have side effects that are deleterious. Additional research need to be done on the stem cells although there are already research done which act as a useful tool for developing drugs and modeling diseases and scientist have confidence of applying them as transplantation medicine. Viruses are nowadays used to induce reprogramming factors into the cells of an adult. In animal, studies have shown that viruses that are applied to the stem cell factors may lead to cancer.

Classification of stem cells on the basis of potency                               

Stem cells can be classified by the extent to which they can differentiate into different cell types. These four main classifications are totipotent, pluripotent, multipotent, or unipotent.

1.      Totipotent

The ability to differentiate into all possible cell types. Examples are the zygote formed at egg fertilization and the first few cells that result from the division of the zygote.

2.      Pluripotent

The ability to differentiate into almost all cell types. Examples include embryonic stem cells and cells that are derived from the mesoderm, endoderm, and ectoderm germ layers that are formed in the beginning stages of embryonic stem cell differentiation.

3.      Multipotent

The ability to differentiate into a closely related family of cells. Examples include hematopoietic (adult) stem cells that can become red and white blood cells or platelets.

4.      Oligopotent

The ability to differentiate into a few cells. Examples include (adult) lymphoid or myeloid stem cells.

5.      Unipotent

 The ability to only produce cells of their own type, but have the property of self-renewal required to be labeled a stem cell. Examples include (adult) muscle stem cells.

Classification of stem cells on the basis of their sources

The easiest way to categorize stem cells is by dividing them into two types: Early or embryonic and mature or adult. Early stem cells, often called embryonic stem cells, are found in the inner cell mass of a blastocyst after approximately five days of development. Mature stem cells are found in specific mature body tissues as well as the umbilical cord and placenta after birth25.                                                                  

a)      Embryonic stem cells

Embryonic stem cells are self-replicating pluripotent cells that are potentially immortal26. They are derived from embryos at a developmental stage before the time of implantation would normally occur in the uterus2. The embryos from which human embryonic stem cells are derived are typically four or five days old and are a hollow microscopic ball of cells called the blastocyst.

b)      Adult stem cells

Adult stem cells are undifferentiated totipotent or multipotent cells, found throughout the body after embryonic development, that multiply by cell division to replenish dying cells and regenerate damaged tissues. The primary roles of adult stem cells in a living organism are to maintain and repair the tissue in which they are found. Unlike embryonic stem cells, which are defined by their origin (the inner cell mass of the blastocyst), the origin of adult stem cells in some mature tissues is still under investigation.

c)     Pluripotent stem cells

 Recently, a third type of stem cell, with properties similar to embryonic stem cells, has emerged. Scientists have engineered these induced pluripotent stem cellsi (iPS cells) by manipulating the expression of certain genes - 'reprogramming' somatic cells back to a pluripotent state.

d)      Stem cell culture

Growing cells in the laboratory is known as cell culture. Human embryonic stem cells (hESCs) are generated by transferring cells from a preimplantation stage embryo into a plastic laboratory culture dish that contains a nutrient broth known as culture medium. The cells divide and spread over the surface of the dish. However, if the plated cells survive, divide and multiply enough to crowd the dish, they are removed gently and plated into several fresh culture dishes. The process of replating or sub culturing the cells is repeated many times and for many months. Each cycle of sub culturing the cells is referred to as a passage. Once the cell line is established, the original cells yield millions of embryonic stem cells. Embryonic stem cells that have proliferated in cell culture for six or more months without differentiating, are pluripotent, and appear genetically normal are referred to as an embryonic stem cell line. At any stage in the process, batches of cells can be frozen and shipped to other laboratories for further culture and experimentation.                                                           

e)      Stem cell lines

A stem cell line is a family of constantly dividing cells, the product of a single parent group of stem cells. They are obtained from human or animal tissues and can replicate for long periods of time in vitro ("within glass"; or, commonly, "in the lab", in an artificial environment). They are frequently used for research relating to embryonic stem cells or cloning entire organism. Once stem cells have been allowed to divide and propagate in a controlled culture, the collection of healthy, dividing, and undifferentiated cells is called a stem cell line.       

Applications of stem cells

The goal of any stem cell therapy is to repair a damaged tissue that can't heal itself. Ongoing research on stem cell therapies gives hope to patients who would normally not receive treatment to cure their disease but just to alleviate the symptoms of their chronic illness. Stem cell therapies involve more than simply transplanting cells into the body and directing them to grow new, healthy tissue. It may also be possible to coax stem cells already in the body to work overtime and produce new tissue.

Possible treatments by stem cells

A number of stem cell therapeutics exist, but most are at experimental stages and/or costly, with the notable exception of bone marrow transplantation. Medical researchers anticipate that adult and embryonic stem cells will soon be able to treat cancer, Type 1 diabetes mellitus, Parkinson's disease, Huntington's disease, Celiac Disease, cardiac failure, muscle damage and neurological disorders, and many others. They have suggested that before stem cell therapeutics can be applied in the clinical setting, more research is necessary to understand stem cell behavior upon transplantation as well as the mechanisms of stem cell interaction with the diseased/injured microenvironment.

 Bone marrow transplants (BMT) are a well-known clinical application of stem cell transplantation. BMT can repopulate the marrow and restore all the different cell types of the blood after high doses of chemotherapy and/or radiotherapy, our main defense used to eliminate endogenous cancer cells. The isolation of additional stem and progenitors cells is now being developed for many other clinical applications. Several are described below.

Skin replacement

The knowledge of stem cells has made it possible for scientists to grow skin from a patient’s plucked hair. Skin (keratinocyte) stem cells reside in the hair follicle and can be removed when a hair is plucked. These cells can be cultured to form an epidermal equivalent of the patients own skin and provides tissue for an autologous graft, bypassing the problem of rejection.

Brain cell transplantation

 Stem cells can provide dopamine - a chemical lacking in victims of Parkinson’s disease. It involves the loss of cells which produce the neurotransmitter dopamine. The first double-blind study of fetal cell transplants for Parkinson’s disease reported survival and release of dopamine from the transplanted cells and a functional improvement of clinical symptoms. However, some patients developed side effects, which suggested that there was an over sensitization to or too much dopamine.  Although the unwanted side effects were not anticipated, the success of the experiment at the cellular level is significant.

Treatment for diabetes

Diabetes affects millions of people in the world and is caused by the abnormal metabolism of insulin. Normally, insulin is produced and secreted by the cellular structures called the islets of langerhans in the pancreas. Recently, insulin expressing cells from mouse stem cells have been generated. In addition, the cells self assemble to form structures, which closely resemble normal pancreatic islets and produce insulin. Future research will need to investigate how to optimize conditions for insulin production with the aim of providing a stem cell-based therapy to treat diabetes to replace the constant need for insulin injections   

Potential uses of stem cells

Since stem cells have the ability to turn into various other types of cells, scientists believe that they can be useful for treating and understanding diseases.

•  grow new cells in a laboratory to replace damaged organs or tissues
•  correct parts of organs that don’t work properly
•  research causes of genetic defects in cells

• research how diseases occur or why certain cells develop into cancer cells

•  test new drugs for safety and effectiveness   

Why are people conducting stem cell research
An embryonic stem cell is derived from embryos. Most of them are derived from those embryos that that grow from eggs that are fertilized in vitro and then taken for the purpose of research after gain the permission of the giver. They are not taken from those eggs whose fertilization occurs at the body of the woman. Cell culture is the process of growing these cells in the laboratory.

 In a human being, embryonic stem cells are generated by transferring them from pre-implantation of the culture dish into a plastic laboratory that has nutrients broth. These cells divide and separate over the face of the dish. In the inner face of the dish, there is an embryonic skin cells coat of mouse embryonic skin cells that have been taken care of to limit them from dividing.

 The cell of the mouse at the base of the culture dish offers a sticky surface where they can attach. They also offer nutrients in to the culture medium. Through the research, there has an innovation of growing without using mouse feeder cells embryonic stem cells. This is a considerable advance because the risk that there could be a virus and other macromolecules in the cells of the mouse that may risk being transferred to the cells of a human being.

Policy challenge
The process of producing a budding cell line in inefficient in a way. This is because cells are not always produced when cells are placed from the pre-implantation stage. However, in case of the plated cell survive, they divide and multiply enough and crowd the whole dish. This makes one to gently remove them and plate them in several other fresh culture dishes. This process is repeated for a number of times until the required cell line is established after the original cell produces embryonic stem cells in millions.

At every stage in the process, cells in batches are shipped and frozen to another laboratory to continue with experiment and culture. At various stages in the practice of creating embryonic, scientists conduct the test for the cell to determine whether they the fundamental properties that can make embryonic stem cells. In the study of human embryonic stem cells, scientists have not agreed on the ordinary battery of examination that can be applied in making the fundamental properties of the cell.

 However, laboratories that that reproduce embryonic cell lines of human being use several type of tests. This in includes: mounting and subculturing the cells, application of specified techniques to evaluate the presence of transcription factors that are produced by undifferentiated cells among others.

Ethical, Social, Political Debate
Embryonic stem cells remain undifferentiated when they are developed under suitable conditions. Nevertheless, if they are allowed to clump they usually form embryoid bodies and begin to separate spontaneously. They are differentiating to form nerve cells, muscles cells, and other type of cell. Although differentiation shows that customs of embryonic stem cells is strong, it is not the best way to generate culture of a type of cell that is specific. To be able to generate culture of specified types of differentiated cells researchers try to manage the separation of the embryonic stem cells. They try to change the work of the customs medium, change the face of the customs dish, or try to change the cell by adding specific genes.

An adult stem cell is said to be the undifferentiated cells that are among the differentiated cells in that can repair it and can differentiate to give in some or all of the main specific type of cell of the organ or tissue. The main roles played by the mature stem cell in an organism are to repair and maintain the tissue where they are found.

The scientists are also known to replace adult stem cells with somatic stem cell, where it is used to refer to the body cells. Unlike the stem cells of the embryonic, which are defined through their origin, an origin of stem cells adult is under investigation up to now.

Their researches have also generated a high level of excitement; they have discovered that the stem cells of the adults are in more tissues than they had thought. This has prompted researchers and clinical officers to researcher whether stem cells of adults can be applied for the transplants. This was found possible, and as adult blood, forming or stem cells of hematopoietic of the adults’ in the bone marrow are used in the transplant for over four decades. They have also proved that these cells are also common in the heart and brain. If this cells variation in the laboratory is controlled, this may be said to the bases for conducting therapies that relate to transplantation.

Stem cell research controversy

Adult stem cells don’t present any ethical problems. However, in recent years, there has been controversy surrounding the way human embryonic stem cells are obtained. During the process of harvesting embryotic stem cells, the embryo is destroyed. This raises ethical concerns for people who believe that the destruction of a fertilized embryo is morally wrong.

Opponents believe that an embryo is a living human being. They don’t think the fertilized eggs should be used for research. They argue that the embryo should have the same rights as every other human and that these rights should be protected.

Supporters of stem cell research, on the other hand, believe that the embryos are not yet humans. They note that researchers receive consent from the donor couple whose eggs and sperm were used to create the embryo. Supporters also argue that the fertilized eggs created during in-vitro fertilization would be discarded anyway, so they might be put to better use for scientific research.

With the breakthrough discovery of iPSCs, there may be less of a need for human embryos in research. This may help ease the concerns of those who are against using embryos for medical research. However, if iPSCs have the potential to develop into a human embryo, researchers could theoretically create a clone of the donor. This presents another ethical issue to take into consideration. Many countries already have legislation in place that effectively bans human cloning.

Potential Impact On Health

Stem cell research is important to the future of medicine because with adequate research, stem cells have the potential to treat degenerative conditions by transplanting human stem cells into patients. Presently, many of these chronic conditions have no cure and are managed by treating the symptoms. While the initial cost of receiving stem cell therapy may be high, it has the potential to outweigh the life long costs incurred through daily medications and hospitalizations. By making disease management easier, the quality of life for those diagnosed with these diseases and their family members would be greatly increased. With sufficient development of stem cell therapy, chronic diseases such as diabetes, heart disease, and Parkinson’s disease may be more effectively managed. To realize the promise of novel cell-based therapies for such pervasive and debilitating diseases, scientists must be able to easily and reproducibly manipulate stem cells so that they possess the necessary characteristics for successful Buku Stem Cell.

Guidelines For Stem Cell Research

1. The Ministry of Health will undertake to encourage and promote stem cell research in Malaysia.

2. All stem cell research and applications must be reviewed by the respective Institutional Review Board (IRB) and/or the Institutional Ethics Committee (IEB) for approval to ensure ethical research and use of stem cells. The IRB and IEC must strictly adhere to the National Guidelines for Stem Cell Research and Therapy.

3. A copy of all research proposals must be submitted to the National Stem Cell Research and Ethics Sub Committee which shall retain the rights to review any research proposal as and when required.

4. All experiments and clinical trials involving stem cells must be based on a solid foundation of basic scientific and animal experimentation and carried out with the highest medical and ethical standards.

5. Research on human adult stem cells is allowed.

6. Research on stem cells derived from foetal tissues from legally performed termination of pregnancy is allowed.

7. Research on non-human stem cells is allowed.

8. Use of embryonic stem cell lines for research purposes is allowed.

9. Research on embryonic stem cells derived from surplus embryos is allowed

10. The creation of human embryos by any means including but not limited to assisted reproductive technology (ART) or somatic cell nuclear transfer (SCNT) specifically for the purpose of scientific research is prohibited.

11. To facilitate autonomous choice and avoid conflict of interest, decisions related to the production of embryos for infertility treatment should be free of the influence of investigators who propose to derive or use hES cells in research. Whenever it is practicable, the attending physician responsible for the infertility treatment and the investigator deriving or proposing to use hES cells should not be the same person.

12. No cash or in-kind payment may be provided for donating blastocysts in excess of clinical need for research purposes.

Conclusion                                                                                  

The pursuit and production of knowledge through scientific research is an undertaking that offers enormous intellectual rewards for researchers while also performing an important social function. The advancement of science has transformed our lives in ways that would have been unpredictable just a half-century ago. Whether stem cell research will have a similar effect remains to be determined, but the promise is so great that it seems wise to consider seriously how best to further such research in a manner that is sensitive to public sensibilities. Public conversations about research and use of human stem cells are well underway. This report is intended to contribute to and inform this ongoing dialogue.

We recognize that science does not exist in isolation from the larger community that feels its effects, whether perceived as good or bad. The work of scientists is, and should be, conditioned and directed by consideration of broader human values. This means that the development of public policy, especially where highly controversial matters are involved, must take all interested sectors of the public into account. It is only through broad-based participation that the values of all stakeholders in the research enterprise can be carefully considered and weighed. We hope that this report has offered an approach that balances the promise of human stem cell research with the public’s genuine concerns about such research in a manner that will lead to a consensus on how best to proceed.       

 Summary Page
A stem cell is specified type of cell possessing unique capability to renew itself and produce specialized types of cells.

Although most body cells are committed to performing specified duties, stem cells are always uncommitted and remain so until they receive signal to develop into specialized cells. Their ability to turn to specialized cells and proliferation capacity to make stem cells unique from all others.

 For several years study have tried to look out for new conduct to apply stem cells in place for diseased or damaged cells and tissues. Recently, much attention has been accorded to stem cells from researchers and clinicians.

Scientists who have an interest in the development of human have been conducting research on it for a number of years. Stem cell has been one of them and has the capability of developing into any type of cell within the body systems. They have the power to develop to all of the known different type of cells. With their unique properties, stem cells are able to turn from fatal tissue and embryo.

To patients and researcher, there are many issues about stem cells that are unsolved. The prediction of the application of the stem cell is impossible particularly because the premature stage of the discipline of the stem cell biology. At present, it is impossible to determine in advance which stem cells or techniques for influencing the cells. This will be best tackle needs for primary research and clinical applications for whose answers will be found by doing more research on the issue.