The difference between stem cell research and therapy is in the scientific evidence that supports therapeutic intervention to be beneficial for the patient.
Stem cells have the remarkable potential to develop into many different types of cells in the body during early life and growth. In addition, in many tissues, stem cells serve as a sort of internal repair system, dividing essentially without limit to replenish other cells as long as the individual is 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 cell research on adult stem cells
Stem cells are distinguished 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, 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 in stem cell research.
In 2006, researchers made a 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 is called induced pluripotent stem cells (iPSCs).
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, lungs, 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.
Stem cell research for treating disease
Given their unique regenerative abilities, stem cells offer new potentials for treating diseases such as diabetes, and heart disease. However, much work remains to be done in the laboratory and the clinic to understand how to use these cells for cell-based therapies to treat disease, which is also referred to as regenerative or reparative medicine.
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. Stem cell research is one of the most fascinating areas of contemporary biology, but, as with many expanding fields of scientific inquiry, research on stem cells raises scientific questions as rapidly as it generates new discoveries.
In 1964, the World Medical Association developed the Declaration of Helsinki as a statement of
ethical principles for medical research involving human subjects. It includes research on identifiable human material and data, last amended in October 2013.
According to the Helsinki Declaration, in the treatment of an individual patient where proven interventions do not exist or other known interventions have been ineffective, the physician, after seeking expert advice, with informed consent from the patient or a legally authorized representative, may use an unproven intervention if in the physician’s judgement it offers hope of saving life, re-establishing health or alleviating suffering.
Intervention should subsequently be made the object of research, designed to evaluate its safety and efficacy. In all cases, new information must be recorded and, where appropriate, made publicly available.
The term stem cell research gleans different reactions from people, both in the medical community and the wider public. Still an emerging science, stem cell research is shrouded by many myths and misconceptions. Here, we take on some of the most predominant myths to discuss the misconceptions and clarify the facts regarding this fast-growing branch of medicine.
Stem cell myths
Myth #1: Stem cells only come from embryos.
FACT: False. Stem cells exist in all bodies, from embryos to adults.
Embryonic stem cells come from the early embryo, and have the potential to produce all the specialized cells of the body. Because of this, they hold great promise for studying and potentially treating disease and injuries. Tissue or “adult” stem cells are found in the body throughout our lives. These cells maintain and repair many tissues in the body. Examples of these cells include blood stem cells, muscle stem cells, bone marrow stem cells, adipose tissue (fat) stem cells and skin stem cells. Some of these adult stem cells are used in established medical and aesthetic treatments.
Myth #2: Induced pluripotent stem cells (iPSCs) eliminate the need for embryonic cells
FACT: False. Research is needed on all types of cells because it is not clear which cells will be most useful for which types of application. For the foreseeable future, side-by-side research on both embryonic and induced pluripotent stem cells is needed. Global Stem Cell Group’s research and treatment products use no embryonic stem cells.
Myth #3: Stem cell research leads to cloning humans.
FACT: False. Most countries prohibit this type of cloning.
In most countries, even attempting to clone a human being is illegal. Some countries do allow something called “therapeutic cloning” for the purposes of studying a disease. In this procedure, scientists isolate embryonic stem cells from a cloned blastocyst (early stage embryo) but do not transfer the blastocyst into a womb. In therapeutic cloning, the blastocyst is not transferred to a womb. Instead, embryonic stem cells are isolated from the cloned blastocyst. These stem cells are genetically matched to the donor organism for studying genetic disease. For example, stem cells could be generated using the nuclear transfer process described above, with the donor adult cell coming from a patient with diabetes or Alzheimer’s. The stem cells could be studied in the laboratory to help researchers understand what goes wrong in diseases like these.
Therapeutic cloning also could be used to generate cells that are genetically identical to a patient’s. A patient transplanted with these cells would not suffer the problems associated with transplant rejection. To date, no human embryonic stem cell lines have been derived using therapeutic cloning.
Myth #4: Adult stem cells are only found in adults
FACT: False. There are three different types of stem cells: embryonic stem cells, induced pluripotent stem cells and tissue specific stem cells. It’s the tissue stem cells that are often called “adult” stem cells, but these “adult” stem cells are found in people of all ages. (See myth #1).
Stem cell myths: research
Myth #5: Embryonic stem cell research is banned in Europe.
FACT: False. The laws vary across the EU.
EU member states have diverging regulatory positions on human embryonic stem cell research. For instance, in Germany, the use of embryos for research is heavily restricted under the Embryo Protection Act (Embryonenschutzgesetz) of 1991, which makes the derivation
of embryonic stem cell lines a criminal offense. But in the UK, embryonic stem cell research is allowed, subject to licensing from the Human Fertilization and Embryology Authority (HFEA). Click here for country by country overviews for more details. Under the previous two European Framework programs (FP6 and F7), as well as the current program, Horizon 2020, human embryonic stem cell research can be funded, provided that the work is permitted by law in the country where it is to take place.
Myth #6: Stem cell research and treatment is against the law in the US.
FACT: False. The FDA does not regulate the practice of medicine, but rather drugs and medical devices and which of these can be marketed in the US. Under federal law, cultured (grown) stem cell products are considered a drug, but are not illegal. Adult stem cells, however, are not cultured—they exist in our bodies throughout our organs, blood, skin, teeth, fat, bone marrow and other places.
Adult stem cell therapy is currently used in the United States to treat conditions such as leukemia and other illnesses. Bone marrow consists of stem cells which have been transplanted for years in the US.
Global Stem Cells Group offers stem cell treatments in countries where stem cell therapy is approved and regulated with no appreciable difference in safety record.. Stem cell therapy technology is still under review by the FDA.
Stem cell myths: therapies
Myth #7: Bone marrow is the best source of stem cells.
FACT: False. Bone marrow is just one source of stem cells. Bone marrow stem cells have been studied for decades, and have been used to treat certain types of cancer. A great deal of research has been dedicated to understanding this source of stem cells and their potential. Bone marrow contains a number of different kinds of stem cells, one of which is mesenchymal stem cells. However, mesanchymal stem cells can also be found in adipose (fat) tissue at nearly 2000 times the frequency of bone marrow.
Mesenchymal cells have the capability to become different types of tissues (blood vessels, muscle tissue, etc.) and are capable of communicating with other cells. In combination with other proteins, molecules and regenerative cells found in adipose tissue, they also have the ability to reduce inflammation, regenerate damaged tissue, and grow new blood vessels, a process known as angiogenesis. Stem cells from adipose tissue are more accessible and abundant. They can be processed immediately and reintroduced into the body right away.
Myth #8: There is a risk of rejection with stem cell therapy.
FACT: False. When a patient’s stem cells are derived from his or her own body (such as fat tissue), there is no risk of rejection. In fact, studies thus far have indicated no safety issues with fat-derived autologous (from self) stem cells. Since these stem cells come from your own body, the risk of rejection is eliminated.
Continuing our recent discussion of stem cell therapies for sports injuries, the use of mesanchysmal stem cells (MSCs) in orthopedic medicine can help in the repair of damaged tissue by harnessing the healing power of undifferentiated cells that form all other cells in our bodies. The process involves isolating these stem cells from a sample of your blood, bone marrow or adipose tissue (fat cells), and injecting it into the damaged body part to promote healing. Platelet-rich-plasma (PRP), a concentrated suspension of platelets (blood cells that cause clotting of blood) and growth factors, is also used to assist the process of repair.
Below are some examples of injuries and areas of research involving the use of mesenchymal stem cells (MSCs), which are (adult) tissue stem cells that are not only able to produce copies of themselves, but also able to divide and form bone, cartilage, muscle, and adipose (fat) stem cells when cultured under certain conditions:
Cartilage has long been considered as an ideal candidate for cell therapy as it is a relatively simple tissue, composed of one cell type, chondrocytes, and does not have a substantial blood-supply network. Of particular interest to researchers is repair of cartilage tissue in the knee, also called the meniscus of the knee. The meniscus is responsible for distributing the body’s weight at the knee joint when there is movement between the upper and lower leg. Only one third of meniscus cartilage has a blood supply, and as the blood supply allows healing factors and stem cells attached to the blood vessels (called perivascular stem cells) to access the damaged site, the meniscus’s natural lack of blood supply impairs healing of this tissue. Damage to this tissue is common in athletes, and is the target for surgery in 60 percent of patients undergoing knee operations, which usually involves the partial or complete removal of the meniscus, which can lead to long-term cartilage degeneration and osteoarthritis.
Recently, researchers increased their focus on the use of MSCs for treatment of cartilage damage in the knee. Some data from animal models suggest that damaged cartilage undergoes healing more efficiently when MSCs are injected into the injury, and this can be further enhanced if the MSCs are modified to produce growth factors associated with cartilage. It has been shown that once the MSCs are injected into the knee they attach themselves to the site of damage and begin to change into chondrocytes, promoting healing and repair. A small number of completed clinical trials in humans using MSCs to treat cartilage damage have reported some encouraging results, but these studies used very few patients, making it difficult to accurately interpret the results. There are currently a number of ongoing trials using larger groups of patients, and the hope is that these will provide more definite information about the role MSCs play in cartilage repair.
Tendinopathy relates to injuries that affect tendons – the long fibrous tissues that connect and transmit force from muscles to bones. Tendons become strained and damaged through repetitive use, making tendinopathy a common injury among athletes. Tendinopathy has been linked to 30 percent of all running-related injuries, and up to 40 percent of tennis players suffer from some form of elbow tendinopathy or “tennis elbow.” Damage occurs to the collagen fibers that make up the tendon, and this damage is repaired by the body through a process of inflammation and production of new fibers that fuse together with the undamaged tissue. However, this natural healing process can take up to a year to resolve, and results in the formation of a scar on the tendon tissue, reducing the tendon’s natural elasticity, decreasing the amount of energy the tissue can store and resulting in a weakening of tendon.
MSCs have the ability to generate cells called tenoblasts that mature into tenocytes. These tenocytes are responsible for producing collagen in tendons. This link between MSCs and collagen is the focus for researchers investigating how stem cells may help treat tendinopathy. Substantial research has been carried out on racehorses as they suffer from high rates of tendinopathy, and the injury is similar to that found in humans. Researchers discovered that by injecting MSCs isolated from an injured horse’s own bone marrow into the damaged tendon, recurrence rates were almost cut in half compared to horses that receive traditional medical management for this type of injury. A later study by the same group showed the MSCs improved repair, resulting in reduced stiffness of the tissue, decreased scarring and better fusion of the new fibers with the existing, undamaged tendon. It is not yet clear if these results are due to MSCs producing new tenocytes or their ability to modulate the environment around the tendinopathy, as described above. These promising results paved the way for the first pilot study in humans.
Bones are unique in that they have the ability to regenerate throughout life. Upon injury, such as a fracture, a series of events occur to initiate healing of the damaged bone. Initially there is inflammation at the site of injury, and a large number of signals are sent out. These signals attract MSCs, which begin to divide and increase their numbers. The MSCs then change into either chondrocytes, the cells responsible for making a type of cartilage scaffold, or osteoblasts, the cells that deposit the proteins and minerals that comprise the hard bone on to the cartilage. Finally these new structures are altered to restore shape and function to the repaired bone. A number of studies carried out in animals have demonstrated that direct injection or infusing the blood with MSCs can help heal fractures that previously failed to heal naturally. However, as was the case with tendinopathy, it is not yet clear if these external MSCs work by generating more bone-producing cells or through their ability to reduce inflammation and encourage restoration of the blood supply to injured bone, or both.
Brain injury in sports
There is mounting evidence that those taking part in sports where they are exposed to repetitive trauma to the head and brain are at a higher risk of developing neurodegenerative disorders, some of which are targets for stem cell treatments. For example, it has been reported that the rate of these diseases, like Alzheimer Disease, were almost four times higher in professional American football players compared to the general population. While the cause of this disease is not yet clear, it is associated with abnormal accumulation of proteins in neural cells that eventually undergo cell death and patients develop dementia. Researchers have attempted a number of strategies to investigate treatments of this disease in mice, including introducing neural stem cells that could produce healthy neurons. While some of these experiments have demonstrated positive, if limited, effects, to date there are no stem cell treatments available for Alzheimer’s Disease.
Boxers suffering from dementia pugilistica, a disease thought to result from damage to nerve cells, can also demonstrate some symptoms of Parkinson’s Disease (among others). In healthy brains, specialized nerve cells called dopaminergic neurons produce dopamine, a chemical that transmits signals to the part of the brain responsible for movement. The characteristic tremor and rigidity associated with Parkinson’s Disease is due to the loss of these dopaminergic neurons and the resulting loss of dopamine production. Researchers are able to use stem cells to generate dopaminergic neurons in the lab that are used to study the development and pathology of this disease. While a recent study reported that dopaminergic neurons derived from human embryonic stem cells improved some symptoms of the disease in mice and rats, stem cell based treatments are still in the development phase.