Stem cell therapy is an innovative science that aims to regenerate or promote the repair of injured and dysfunctional tissue using stem cells. Stem cells are pure and raw cells found in the body but are more prevalent in embryos with no specific function. They are cells from which all other specialized cells can generate their function through a process called differentiation.
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Where they come from
Stem cells can come from two different places: embryos and adult tissues.
Embryonic stem cells come from three to five-day-old embryos, called blastocysts, with around 150 cells. They are pluripotent stem cells, which can divide into more stem cells or develop into any cell in the body. This adaptability allows embryonic stem cells to be used in regenerative medicine.
Adult stem cells are found in small numbers in adult tissues such as fat and bone marrow. They have limited abilities in differentiation, meaning they cannot give rise to specialized cells as much as embryonic stem cells. Scientists believed that adult stem cells could only create similar types of cells. For example, stem cells from the bone marrow could only generate erythrocytes. However, new research suggests that adult stem cells may have the capacity to create more types of cells, and adult stem cells are currently being tested in people with neurological or heart disease. Researchers have found that adult stem cells can possibly be altered to have similar characteristics to embryonic stem cells; these are called induced pluripotent stem cells (iPS).
What they can be used for
Stem cells can be used for transplants, requiring them to first specialize into a specific adult cell type. Once matured, the cells can replace the tissues damaged by disease or injury. They can be used to replace neurons damaged by an injury, a stroke, Alzheimer’s disease, Parkinson’s disease, and other neurological problems. They also can produce insulin and be a treatment for people who have diabetes and repair damaged cartilage. Ultimately, they can replace any tissue or organ that is injured.
There have been some studies on the use of stem cell therapy for neurodegenerative diseases. Due to the generation of neural cells from stem cells, they have been used in clinical trials targeting these diseases. The stem cell therapies slow down the progression of neurodegenerative diseases such as Parkinson’s, Alzheimer’s, amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), and thoroughly treating them.
Example: Multiple sclerosis
Multiple sclerosis, or MS, is an inflammatory and neurodegenerative autoimmune disorder of the central nervous system. Stem cell studies are looking at the possibility of slowing down the progression of MS as well well as reversing the neural damage associated with it. In 2014, there was a phase 1 clinical trial by CelgeneTM that used placental-derived mesenchymal stem cells infusion to treat MS. The results demonstrated the safety of the treatment. The clinical trial included ten randomly picked patients with relapsing-remitting multiple sclerosis and six with secondary progressive multiple sclerosis. People who have relapsing-remitting MS first notice signs of the disease in their early 20s. Later on, they start having attacks of symptoms (relapses) from time to time, followed by recovery (remissions). In this type of MS the nerves are affected, but the severity, degree of recovery and time between relapses vary. Those who have secondary progressive MS have lived with relapsing-remitting MS for many years, and the relapsing-remitting MS becomes secondary progressive MS. The symptoms progress without relapses or remission, which happens 10-20 years after diagnosis. In the trial, 6 patients were administered a low dose PDA-001 (a preparation of mesenchymal-like cells derived from full-term human placenta), 6 received a high dose, and 4 received a placebo. The conclusion was that the PDA-001 infusions were safe and patients with relapsing-remitting multiple sclerosis and secondary progressive were able to tolerate it well.
Controversy and Ethical Issues
Since the discovery of stem cells and their use in medical research, some controversy arose and caused some problems between people with different beliefs. In the 1990s, scientists were only deriving the human stem cells from embryos. For many, this meant that extracting these cells would destroy the embryo, which was a complex subject due to the different beliefs on what constitutes the start of human life. Some believe that life starts at birth, others believe that it begins when an embryo becomes a fetus, and others believe it starts right at conception.
However, in 2006, researchers started using induced pluripotent stem cells, which are not derived from embryos. This eliminated the ethical concern that many had in the 1990s. Because of this, stem cell technology is beginning to advance, and people’s attitudes toward stem cell research are changing. There are still some concerns, such as making sure that the donors give proper consent and the careful consideration and design of clinical studies.
Warnings
Unproven stem cell treatments can be unsafe, and some providers offer stem cell products that are unapproved and unproven. Stem cell therapies may potentially treat diseases that have no or few current treatments, and the scientific research constantly advances, but they are still relatively less studied. The Food and Drug Administration (FDA) is increasing its enforcement to protect people from dishonest clinics but still encouraging the innovation of the medical industry in the study of stem cells. To stay safe, it is crucial to research whether the treatment one is seeking is FDA-approved or being studied under an Investigational New Drug Application (IND), a clinical investigation plan allowed by the FDA.
Article author: Celine Guirguis
Article editors: Sherilyn Wen, Maria Giroux