Stem Cells - Final Assignment

Stem Cells

Stem cells are in detail biological cells found in all multicellular organisms. This cells can divide  through mitosis and differentiate into various specialized cell types. It can also self-manipulate to produce more stem cells on the specific site. In mammals, there are two broad types of stem cells: adult stem cells, which are found in various tissues and embryonic stem cells which are isolated from the inner cell mass of blastocysts. In matured organisms, stem cells and progenitor cells act as a repair system for the body, replenishing adult tissues and rejuvenating it. In a developing embryo, stem cells can differentiate into all the specialized cells (these are called pluripotent cells), but also maintain the normal turnover of regenerative organs, such as blood, skin, or intestinal tissues.

Stem cells can now be artificially grown and transformed into specialized cell types with characteristics consistent with cells of various tissues such as muscles or nerves through the process of cell culture. Adult stem cells which contains high plastic cells are routinely used in medical therapies and recoveries. Stem cells can be taken from a variety of sources, for instance umbilical cord blood and bone marrow.  Future therapies by promising candidates have proposed that embryonic cell lines and autologous embryonic stem cells may be generated through therapeutic cloning. Research into stem cells grew out of findings by Ernest A. McCulloch and James E. Till at the University of Toronto in the 1960s.(wikepedia)

There are three sources of autologous adult stem cells:

1) Bone marrow, which requires withdrawal by harvesting, that is, drilling into bone (typically the femur or illiac crest),

 2) Adipose tissue (lipid cells), which requires removal by liposuction, and

3) Blood, which requires extraction through pheresis, wherein blood is drawn from the donor, (similar to a blood donation) passed through a machine that extracts the stem cells and proceeds other portions of the blood to the donor.

Of all stem cell types, autologous harvesting involves the least risk. By definition, autologous cells are obtained from one's own body, just as one may stock his or her own blood for possible surgical procedures.

In other words, stem cells have the remarkable potential to develop into many different cell types in the body during premature life and growth. In many tissues they serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.

Stem cells are notable from other cell types by two important characteristics. First, they are unspecialized cells capable of renewing themselves through cell division, sometimes after long periods of inactivity. Second, under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions.

Until recently, scientists primarily worked with two kinds of stem cells from animals and humans: embryonic stem cells and non-embryonic "somatic" or "adult" stem cells. Scientists discovered ways to derive embryonic stem cells from early mouse embryos nearly 30 years ago, in 1981. The detailed study of the biology of mouse stem cells led to the discovery, in 1998, of a method to derive stem cells from human embryos and grow the cells in the laboratory. These cells are called human embryonic stem cells. The embryos used in these studies were created for reproductive purposes through in vitrofertilization procedures. When they were no longer needed for that purpose, they were donated for research with the informed consent of the donor. In 2006, researchers made another breakthrough by identifying conditions that would allow some specialized adult cells to be "reprogrammed" genetically to assume a stem cell-like state. This new type of stem cell, called induced pluripotent stem cells (iPSCs), will be discussed in a later section of this document.

Stem cells are important for living organisms for many reasons. In the 3- to 5-day-old embryo, called a blastocyst, the inner cells give rise to the entire body of the organism, including all of the many specialized cell types and organs such as the heart, lung, skin, sperm, eggs and other tissues. In some adult tissues, such as bone marrow, muscle, and brain, discrete populations of adult stem cells generate replacements for cells that are lost through normal wear and tear, injury, or disease.

Laboratory studies of stem cells enable scientists to learn about the cells’ essential properties and what makes them different from specialized cell types. Scientists are already using stem cells in the laboratory to screen new drugs and to develop model systems to study normal growth and identify the causes of birth defects.

Research on stem cells continues to advance knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms.

Treatment

Medical researchers believe that stem cell therapy has the potential to dramatically change the treatment of human disease. A number of adult stem cell therapies already exist, particularly bone marrow transplants that are used to treat leukemia. In near future, medical researchers predict being able to use technologies derived from stem cell research to treat a wider variety of diseases including cancer, Parkinson's disease, spinal cord injuries, sclerosis, multiple, and muscle damage, amongst a number of other impairments and conditions. However, there still exists a great deal of social and scientific uncertainty surrounding stem cell research, which could possibly be overcome through public debate and future research.

            One concern of treatment is the risk that transplanted stem cells could form tumors and become cancerous if cell division continues uncontrollably. Stem cells are widely studied, for their potential therapeutic use and for their inherent interest.

Supporters of embryonic stem cell research argue that such research should be pursued because the resultant treatments could have significant medical potential. It has been proposed that surplus embryos created for in vitro fertilization could be donated with consent and used for the research.

 

 

Research Ethics and Stem Cells

            Stem cells show potential for many different areas of health and medical research, and studying them can help us understand how they transform into the dazzling array of specialized cells that make us what we are. Some of the most serious medical conditions, such as cancer and birth defects, are caused by problems that occur somewhere in this process. A better understanding of normal cell development will allow us to understand and perhaps correct the errors that cause these medical conditions.

Research on one kind of stem cell—human embryonic stem cells—has generated much interest and public debate. Pluripotent stem cells (cells that can develop into many different cell types of the body) are isolated from human embryos that are a few days old. Pluripotent stem cell lines have also been developed from fetal tissue (older than 8 weeks of development).

As science and technology continue to advance, so do ethical viewpoints surrounding these developments. It is important to educate and explore the issues, scientifically and ethically.

•         Respect for the person (Autonomy)

Respect here refers to the value of human life. Since through embryonic cultivation, clone species of the fetuses can be formed. Religious views contradict with this standard as we should not be God’. We should not mess around with human life as it is God’s will to deal with it. Scientific explanation differs from this belief thoroughly claiming that whatever benefits mankind gains in the name of science is adequate not taking the adverse effects into considerations.

•         Beneficence (Do Good)

            Since stem cells have the ability to differentiate into any type of cell, they offer something in the development of medical treatments for a wide range of conditions. Treatments that have been proposed include treatment for physical trauma, degenerative conditions, and genetic diseases (in combination with gene therapy). However further treatments using stem cells could potentially be developed due to their ability in repairing extensive tissue damage.

Great levels of success and potential have been shown from research using adult stem cells. In early 2009, the FDA approved the first human clinical trials using embryonic stem cells. Embryonic stem cells can become all cell types of the body which is called pluripotent. Adult stem cells are generally limited to differentiating into different cell types of their tissue of origin. Nevertheless, some evidence suggests that adult stem cell plasticity may exist, increasing the number of cell types a given adult stem cell can become. In addition, embryonic stem cells are considered more useful for nervous system therapies, because researchers have struggled to identify and isolate neural progenitors from adult tissues since it’s very minute in size or structure.

•         Nonmaleficence (Do No Harm)

The stem cell controversy is the ethical debate centered only with research involving the creation, usage, and destruction of human embryos drastically. Most commonly, this controversy focuses on embryonic stem cells. Not all stem cell research involves the creation, usage and destruction of human embryos. For example, adult stem cells, amniotic stem cells and induced pluripotent stem cells do not involve creating, using or destroying human embryos and thus are minimally, if at all, controversial. In other words stem cells do not cause harm as it caters more benefits compared to damage.

•         Justice (Fairness)

Justice here again refers to the question of whether will there be equal treatment of true virtue of those cloned beings. It is indeed an argumentative topic in the sense of ethics and right codes of conduct. Ethical desiderata include: equitable access, maximized potential therapeutic benefit across demographic and disease groups, and reasonable cost. Other ethical priorities include the minimization of stem cell line and tissue wastage, risk of immune rejection, risk of transmitting diseases, the use of human embryos, and risk to those contributing source cells. The therapeutic potential of stem cells for treating and possibly curing many serious diseases constitutes a major justification for large-scale investments of public and private resources in human stem cell research. To justify doing so, however, requires some guarantee that people in need will have access to the therapies as they become available. Principles of justice are based on treating persons with fairness and equity and distributing the benefits and burdens of health care as fairly as possible in society. This would require equitable access to the benefits of stem cell research, without regard to the ability to pay.

 

 STEM CELL RESEARCH - ARGUMENTS REGARDING THE USAGE OF THE KNOWLEDGE

The following arguments are not exclusively in use when talking about stem cell research.

Pros

Stem cell research can potentially help treat a list of medical problems. It could lead humanity closer to better treatment and possibly cure a number of diseases:

• Parkinson’s Disease
• Alzheimer’s Disease
• Heart Diseases, Stroke and Diabetes (Type 1)
• Birth Defects
• Spinal Cord Injuries
• Replace or Repair Damaged Organs
• Reduced Risk of Transplantation (You could possibly get a copy of your own heart in a heart-transplantation in the future
• Stem cells may play a major role in cancer

Better treatment of these diseases could also give significant social benefits for individuals and economic gains for society in whole.

Cons

• Some argue that stem cell research in the far future can lead to knowledge on how to clone humans. It is hard to say whether this is true, but we have seen devastating consequences of other research-programs, even with good intentions, such as nuclear research which could cause massive massacre.
• "Humans should not be trying to play God"

CONCLUSION

The stem cell-research is an example of the, sometimes difficult, cost-benefit analysis in ethics which scientists need to do. Even though many issues regarding the ethics of stem cell research have now been solved, it serves still as a priceless example of ethical cost-benefit analysis.

The advancement of science has transformed our lives in ways that would have been unpredictable just like 50years 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 community sensibilities. Open conversations about research and use of human stem cells are well underway. If humankind were to take stem cells to a higher understanding, extracting only the beneficial outcomes it will surely improve our  living standards.

Reference

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9.     Ariff Bongso; Eng Hin Lee (2005). "Stem cells: their definition, classification and sources". In Ariff Bongso; Eng Hin Lee. Stem Cells: From Benchtop to Bedside. World Scientific. pp. 5. ISBN 981-256-126-9.

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