Stem cells

Introduction 

• Stem cells are undifferentiated, unspecialised with no ‘specific’ function until they differentiate. They have the characteristic of self-renewal, meaning that they can divide and make identical copies of themselves repeatedly. They can be specialised with the potential to produce over 200 different types of cells in the body. Stem cells can divide and renew themselves through multiple cycles of cell growth and division, also known as cell proliferation. The plasticity of stem cells means that they can differentiate into different types of cells, such as muscle cells, blood cells, and brain cells. Stem cell research and usage raises ethical concerns regarding their extraction from embryos. 

Obtaining stem cells for therapeutics 

• Adult stem cells can be found in the bone marrow and are multipotent, meaning that they can differentiate into multiple types of stem cells. Therapeutic cloning is when stem cells are made with the same genetic information as the patient. This means cells produced by the stem cell will all contain the same genetic information as the patient. Therefore, the stem cells will not be rejected by the body, making it a good option for patients like burn victims, as stem cell treatment can speed up healing, reduce risk of infection, and regenerate the skin. Early human embryos contain stem cells which, unlike those found in the bone marrow, are pluripotent and can differentiate into any human body cell. Embryonic stem cells are obtained from embryos that are left over from in vitro fertilisation procedures.  

• The embryos are collected from eggs that were fertilized in a lab but never implanted in a woman's uterus. The embryos are usually 4–5 days old and are in the blastocyst stage, which is when the egg has divided into a hollow ball of about 100 cells. The inner cells mass of the blastocyst contains the embryonic stem cells which are then isolated and placed in a dish to grow. Embryonic stem cells can be used to treat diabetes. Patients with type 1 diabetes do not produce enough insulin to regulate their blood sugar levels. Embryonic cells can differentiate into functioning insulin-producing pancreatic cells and then transplanted into the patient to help maintain their blood sugar levels. 

Common stem cell clinical considerations 

• A common issue with this kind of treatment is the body will often reject the transplanted cells, leaving the treatment will be ineffective. Stem cell graft rejection is more common in allogeneic transplants, where patient's diseased cells are replaced with healthy cells. This occurs especially when the donor is unrelated or less well matched. Graft rejection may be treated with growth factors such as hepatocyte growth factor. HGF expression is necessary for the proliferation, migration, and survival of cells involved in repair of various tissues, including the heart, lung, kidney, liver, brain, and skin. The most common treatment for failure to engraft is another transplant, possibly with stem cells from a different donor. 

• There is also the concern that stem cells grown in labs can become contaminated with viruses which are then passed on to patients when used as treatments. This creates a potential risk of further sickness in the patient. A Pew research study identified 334 cases of harm related to unapproved stem cell interventions, including lifelong disabilities and death. This number includes at least two cases of septicaemia, a life-threatening blood infection; serious and even lifelong disabilities. Some examples include partial or complete blindness (9); paraplegia (1); pulmonary embolism (6); cardiac arrest (5); tumours, lesions, or other growths (16). There is also a risk of organ damage or failure that in several cases that resulted in death. 

Ethical implications of stem cell research and use 

• Some with religious beliefs, particularly in Christianity, Judaism, and Islam, teach that life begins at conception or very early in the embryonic stage. Because of this, they believe that the destruction of embryos ethically unacceptable. Opponents of embryo-based stem cell research often argue that human embryos, even in their early stages of development, should be treated as human beings with inherent dignity and moral worth. This is because human embryos are deemed potential human lives and therefore should not be used to create treatments. They view the destruction of embryos for research as equivalent to taking a human life. They urge scientists to find ways to use other sources of stem cells for medical treatments.  

• Others believe that the curing ill people is more important that the rights of embryos. Therefore, embryonic stem cells should be used where possible. Their argument is that embryos that are used are typically unwanted ones from fertility clinics that would probably be destroyed anyway. This result in the view that it would be a waste not to use them. Embryonic stem cell supporters often argue that the moral status of an embryo, especially those created in vitro, is not equivalent to that of a fully developed human being. For them, the potential to save or improve the lives of existing patients outweighs the ethical concerns about embryos and the focus should be on reducing suffering in the living. 

• Scientists are exploring other sources of stem cells. This includes induced pluripotent stem cells (iPSCs), which do not involve the destruction of embryos. iPSCs are generated by reprogramming adult cells to behave like embryonic stem cells, providing an ethical alternative for research and treatment development. Parkinson’s disease is an example of a disease that is being studied with iPSCs, as they can be used to model PD because they can be differentiated into dopaminergic neurons, which are susceptible to the neurodegeneration that causes PD. This could be the common ground for both viewpoints. As science progresses, there is a growing emphasis on finding ethical alternatives to using human embryos while continuing to explore the promise of stem cell-based therapies. 

Conclusion 

• The differentiation of stem cells into many somatic cells has accelerated our understanding of molecular biology. The new specific cells contribute to the absorption of nutrients and maintenance of specific biomolecular activity. Adult stem cells from bone marrow can form many new tissues and organ systems that keep the human body alive, but not as many as embryonic stem cells. Issues can arise with stem cells use, including rejection of the cells from the body, and rejection from people may be concerned about the ethical implications of manipulating human cells. Ultimately, the issues require careful consideration of both ethical principles and the potential and capacity to improve human health.