Stem cell research has never been more advanced, and as a result many different types of treatments are currently offered on the market. Unfortunate
ly, some providers are practicing quackery in stem cell therapies, and an abundance of well-intentioned scientific and medical personnel are prematurely publicizing their work. These providers and publishers have cast an unfair shadow of mistrust on this very important branch of medical research and potential treatments.
On the other hand, the contributions of professional medical and stem cell societies and other organizations require self-regulation through accreditation and certification, development of standards, and creation of a platform for collaboration among stakeholders.
Professional Guidelines for responsible Stem Cell Research
International Society for Stem Cell Research (ISSCR) is the largest professional organization of stem cell scientists. In 2007, ISSCR impaneled a broad international taskforce to develop a set of professional guidelines for responsible translational stem cell research. Their principles include high standards of preclinical evidence, peer review, scrupulous review of clinical protocol by an Institutional Review Board (IRB), rigorous informed consent, and publication of results whether positive or negative.
The general scientific consensus is that most stem cell therapies are not ready for marketing or commercialization. But the industries that are providing these treatments are increasingly sophisticated and organized, and are challenging established regulatory frameworks.
The International Society for Cellular Therapy (ISCT) has an interest in the promotion of stem cell research and development, but it also is interested in a broader range of cell-based interventions such as immune cell interventions, reproductive medicine, and gene therapy. The ISCT taskforce has working groups on definitions, scientific evidence and biological rationale, laboratory cell processing, clinical practice, regulation, commercial implications, communications, and policy.
Develop terminology, define levels of scientific evidence in new guidelines for stem cell research
The key goals are to develop an appropriate terminology, define the levels of scientific evidence needed to justify routine use or commercialization of a stem cell therapy, address questions of “experimental” and “innovative” use, and understand the global regulatory landscape in order to identify gaps and contradictions.
The ISSCR published revised guidelines for research and clinical translation involving stem cells on May 12, 2016. These new guidelines update and combine guidelines on stem cell research and clinical translation previously issued in 2006 and 2008 Jonathan Kimmelman, Associate Professor of Biomedical Ethics at McGill University, chaired the ISSCR Guidelines Update Task Force. The task force was made up of 25 experts in basic research, clinical research, and bioethics, and received feedback from 85 external individuals and organizations.
2016 guidelines: covering new ground in stem cell research
The 2016 guidelines cover new ground in areas such as gene editing and induced pluripotent stem cells. They introduce a new focus on the communication of results. The task force recognizes that results and potential applications can be exaggerated, leading to distorted understandings of research outcomes in the scientific community, popular press, and among potential patients. The “14-day rule” limiting experimentation on human embryos or embryo-like structures is upheld in these guidelines, although one task-force member has suggested that this may soon be open to revision.
In May, 2016 ISSCR released the following list of all of the new topics addressed in the revised guidelines as part of the announcement of its report:
- Define an Embryo Research Oversight (EMRO) process to encompass both human embryonic stem cell research and human embryo research that may not explicitly pertain to stem cells or generating new stem cell lines;
- Exclude the generation of induced pluripotent stem cells (iPS cells) from specific stem cell research oversight, and instead call on the existing human subjects review processes to oversee donor cell recruitment (iPS cells behave like embryonic stem cells but are derived by reprogramming more differentiated tissue cells);
- Support laboratory-based research that entails gene editing of the nuclear genomes of human sperm, egg, or embryos, when performed under rigorous review, but hold that any attempt to apply this clinically would be premature and should be prohibited at this time;
- Define principles for evaluating both basic and clinically applied research on mitochondrial replacement therapy, in concordance with recent deliberations in the U.K., U.S., and elsewhere;
- Determine that where there is no undue financial inducement to participate, it may be acceptable to compensate women who donate eggs for research;
- Recognize that the development of increasingly complex in vitro models of early stages of human development should undergo specialized review;
- Highlight opportunities to strengthen preclinical studies in stem cell research, including reproducibility and stringent standards for experimental design;
- Call for robust standards for preclinical and clinical research evidence as clinical trials progress and rigorous evaluation for safety and efficacy before marketing approval;
- Address the valuable contributions made by patients or patient groups to support clinical research and a framework to ensure this is achieved without compromising the integrity of the research;
- Highlight the responsibility of all groups communicating stem cell science and medicine—scientists, clinicians, industry, science communicators, and media—to present accurate, balanced reports of progress and setbacks.
The good news is that stem cell research is evolving into a highly respected and in-demand branch of healing that many consider to be the future of medicine. Since pluripotent stem cells have the ability to differentiate into any type of cell, they are used in the development of medical treatments for a wide range of conditions including physical trauma, degenerative conditions, and genetic diseases (in combination with gene therapy). Further treatments using stem cells are being developed due to stem cells’ ability to repair extensive tissue damage.
Great levels of success and potential have been achieved from research using adult stem cells. In early 2009, the FDA approved the first human clinical trials using embryonic stem cells. Embryonic stem cells are pluripotent, which means they can become any cell type of the body, with the exception of placental cells. More and more is being discovered about the plasticity of adult stem cells, increasing the potential number of cell types an adult stem cell can become.
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.
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).
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.
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.
Gordie Howe’s Stem Cell Treatments Support a Growing Appeal for These Therapies Among Athletes and Baby Boomers
In October, 2014, legendary hockey player Gordie Howe, then 86, was on death’s door after suffering a debilitating acute hemorrhagic, left thalamus stroke. Upon returning home from the hospital, Howe needed someone to lift him from his bed to a wheelchair and back. He couldn’t remember the names of his four children, Marty, Mark, Cathy, and Murray, and his condition continued to grow worse in subsequent weeks. According to an article in New York Magazine, when Mark took hid father to get an epidural to relieve his back pain, the attending physician took one look at Gordie and asked Mark if it might be better to just let his father go. On the rare occasion when Gordie did mange to speak, he would tell his children, “Just take me out back and shoot me.”
Howe retired from hockey at age 52, having scored more goals than any other player. But over the past 10 years, his health declined dramatically—heart disease, dementia, and spinal stenosis—despite his family’s and physician’s best efforts to find medical solutions. After his stroke, Keith Olbermann aired a preemptive obituary on ESPN. The family made funeral plans. Murray, his youngest son, wrote a eulogy.
Around Thanksgiving, 2015, Howe’s family learned about an experimental stem cell treatment that could save his life. The plan was to inject up to 100 million neural stem cells into his spinal column in the hopes that the stem cells would migrate to his brain and help his body repair itself. Howe could improve within 24 hours, and receive the treatment anytime—just not in the United States. The procedure wasn’t FDA-approved, and Howe would have to receive the treatment at a clinic in Tijuana.
Howe’s son Murray, a radiologist, looked into the treatment and thought it was promising. The real concern was transporting the immobile Howe to Mexico. Daughter Cathy worried that he might die during the treatment, but Mark responded bluntly: “If he does die, what’s the difference? He’s going to be gone soon no matter what.”
While the family weighed the stem cell treatment idea, Howe was admitted to the hospital with severe dehydration, caused by his unwillingness to swallow. When he returned home, he still had no use of his right side, and the family
assumed he would never walk again. The Howe children decided to give the stem cell treatments a try.
Two days later, the Howes flew their Dad to San Diego. In the air, Gordie grew agitated and got the attention of a flight attendant, who spent 10 minutes kneeling by his seat trying to understand something he wanted to tell her. Due to his profound memory loss, Howe didn’t know he had suffered a stroke, why he was on a plane, or where he was going. But he remembered one thing, which he managed to whisper to the fight attendant: “I was a pro hockey player.”
The next morning, Marty and Murray drove with their father across the border to Clínica Santa Clarita, where Gordie bent over a table to expose his lower back so that a needle could be inserted into his spinal canal to inject the stem cells. Howe was given two types of stem cells – neural stem cells and mesenchymal stem cells. The second type, derived from bone marrow, has anti-inflammatory properties and secretes chemicals that promote healing.
The procedure then required Howe to lie prone for eight hours. After the eight hours passed, Gordie told Murray he needed to use the bathroom and that he intended to walk there in order to do so. Since the stroke, Gordie had only managed to walk one time—10 steps, with a walker. Murray reminded his Dad that he couldn’t walk.
Howe stood up, and with Murray’s support, walked for the first time in more than a month—to the bathroom. This milestone became an oft-repeated story among the Howe family, and Gordie’s revival became an irresistible story for the sports pages. Back home, Gordie returned to something resembling the normal life of an 86-year-old. He pushed the grocery cart, helped with the dishes, and could go fishing so long as one of his sons reminded him that a tug on the line meant he needed to start reeling. The family released a video of Gordie standing stationary, firing a puck, five-hole, past his 8-year-old great-grandson. Keith Olbermann apologized for his premature obituary.
Howe’s children now had to figure out how to share his apparent recovery—a debate that proved just as contentious as their decision to fly him to Mexico for the treatment in the first place—with the world. Both Marty and Mark had played in the NHL alongside their father, but now Murray, the doctor, was giving interviews in his hospital scrubs, endorsing his father’s place in medical “miracle” history. He began referring to the stem-cell treatment as the “Gordie Howe Protocol,” and said that his Toledo-based hospital was looking into conducting an FDA-approved study of the procedure. In one interview, Murray Howe stated that “stem cells are the most promising thing in medicine since the discovery of antibiotics.”
As the story spread, the medical community started to question just how miraculous Howe’s recovery had been.
“Companies selling these products are preying on desperate and vulnerable people and exploiting their hope, much like snake-oil salesmen have done throughout most of human history,” wrote Judy Illes and Fabio Rossi, stem-cell experts at the University of British Columbia, in the Vancouver Sun. Even advocates pointed out that, though the field holds great promise, no reputable studies have shown that such a procedure should work.
And yet, for the children of ailing parents, such skepticism doesn’t matter. Murray’s response to one skeptic was, “What would you do for your father?”
Gordie Howe’s therapy, would cost an average patient about $30,000.
Athletes, whether playing or retired, have a special need for the regenerative capacity that stem cells are believed to provide. Athletes break bones, strain ligaments, bash knees and wear out cartilage. If stem cells’ restorative capability is proven, they could be considered the latest form of sports medicine.
Since Howe’s treatment in late 2014, two other athletic legends have received stem cell treatments—former quarterbacks Bart Starr and John Brodie. And the rest of the population, particularly aging baby boomers, isn’t far behind.
Still, while acceptance of stem cell therapy has grown, so have controversies surrounding its use. While clinical trials authorized by the U.S. Food and Drug Administration are rapidly expanding in the U.S., so are treatments outside the regulated system. Patients are going to stem cell clinics in other countries that approve stem cell therapies.
For its part, the FDA is drafting guidelines, although the U.S. and Canada still trail other countries in approving stem cell treatments.
Last year, the FDA issued draft guidelines to clarify what types of human cell therapy it regulates. The short answer: Most of them, with “limited exceptions,” according to an FDA email sent in response to questions from The San Diego Union-Tribune. These exceptions include cells or tissues that are “minimally manipulated,” not given with any other product and perform the same function in the donor as in the recipient.
All other stem cell therapies are seen as involving human cells, tissues and cellular and tissue-based products – also known as HCT/Ps – regulated by the FDA’s Center for Biologics Evaluation and Research.
“We understand that determining the appropriate regulatory path for HCT/Ps can be challenging, and the FDA is working diligently to develop guidance to help sponsors and physicians understand how to apply federal regulations to this complex and emerging field,” the agency said.
In January 2015, University of California, Davis stem cell researcher and blogger Paul Knoepfler estimated that more than 100 unauthorized stem cell clinics were operating in the United States. Later that year, he increased that estimate to up to 200.
Then on May 6, he wrote on his blog: “We are seeing a flood of professional athletes getting stem cell treatments in the past few years.”
Athletes and others who want these treatments bristle at what they call cumbersome, time-consuming regulations in the U.S. The situation can be urgent for seriously ill patients.
While it hasn’t been proven that the stem cells enabled his recovery, by all indications Gordie Howe’s health has improved significantly since receiving stem cell treatments. In November, 2015, Murray Howe said that his father’s physicians in the U.S. recommended hospice care in the weeks after the stroke, and the family was told he wouldn’t last more than two or three weeks,
“Then, suddenly, he is raking and sweeping and goofing around in the back yard,” Murray said.
Sources: The San Diego Union-Tribune, New York Magazine
Scientists may be one step closer to a breakthrough that uses stem cells to replace damaged skull and facial bones in patients who experience a head trauma or undergo cancer surgery requiring repair and reconstructive surgery.
Researchers have discovered and isolated stem cells capable of repairing these bones in mice. The research, led by Takamitsu Maruyama and the research team at the University of Rochester Medical Center in Rochester, N.Y., could also help patients born with a skull deformity known as craniosynostosis, which can lead to developmental delays and pressure on the brain.
In the study, scientists investigated the role of the Axin2 gene in bone formation and regeneration. They also examined a specific mutation that causes craniosynostosis in mice. Their finding show that stem cells involved in skull formation are contained within this cell population. These cells are specificto the bones in the head and are very different from other stem cells involved in the formation of the bones in the legs and other parts of the body.
Tests to uncover these cells could also help physicians detect bone diseases caused by stem cell abnormalities, according to the researchers.
The research was published Feb. 1 in the journal Nature Communications.
Researchers from the University of Toronto and The Ottawa Hospital were looking to see if mesenchymal stem cells (MSCs) might treat osteoporosis. MSCs are multipotent stromal cells that can differentiate into a variety of cell types, including: bone cells (osteoblasts), cartilage cells (chondrocytes), muscle cells (myocytes) and fat cells (adipocytes).
Faulty MSCs are the culprits behind osteoporosis; after injecting healthy MSCs into mice with the affliction that causes bones to become weak and brittle, researchers were hoping for a general increase in the mice’s bone health. Instead, they were surprised (and probably very excited) to discover after six months—a quarter of a mouse’s life span—that healthy, functioning bone had replaced the damaged osteoporotic bone. The bone structure in the little creatures, which had been severely compromised by osteoporosis, had been restored to a normal, healthy state! The healthy mesenchymal stem cells did what they were born to do. They became bone cells and went to work, much like the restoration of an old building at the hands of architects and laborers, only without the scaffolds and noise. MSCs work very quietly.
Researchers are hoping that these findings could lead to a new way of treating osteoporosis in humans, or even delay its onset indefinitely.
Stem cell researchers have known for some time that MSCs can boost the regeneration of bone, and in fact a test group of elderly patients in the U.S. who suffer from osteoporosis have already received MSC injections as part of an ancillary trial. The research team is preparing to to examine their blood samples to see if biological markers indicate an improvement in bone growth and bone reabsorption.
Depending on the outcome of those blood tests, larger trials involving human patients could follow within the next 5 years.
In addition to working quietly and therefore not waking you to the sound of a jackhammer at 7 a.m., there are other cool qualities to MSCs. For instance, they are “a heterogeneous population of musculoskeletal progenitors (another name for adult stem cells) that includes skeletal stem cells (SSCs).” An added perk is that they can be transplanted between individuals without the need to be matched, and without the risk of rejection.
MSCs are awesome.
Globally, more than 200 million people are living with either postmenopausal osteoporosis—known as type 1 osteoporosis, which affects mainly women, or age-related type 2 osteoporosis, which affects both men and women.
With type 2 osteoporosis, there is a reduction in the inner structure of the bone. The bone becomes thinner and less dense, and it can no longer function properly.
Worldwide, type 2 osteoporosis leads to around 8.9 million bone fractures annually. Hip fractures are among the most common fractures related to osteoporosis, which can lead to disability and even death in elderly patients.
Currently, Teriparatide (brand name Fortéo) is the only drug available to treat type 2 osteoporosis, and its effectiveness lasts for only two years.
The senior author of the study, titled Systemic Mesenchymal Stromal Cell Transplantation Prevents Functional Bone Loss in a Mouse Model of Age-Related Osteoporosis, and published March 17, 2016, is William Stanford, Ph.D., a senior scientist at The Ottawa Hospital Research Institute and a professor at the University of Ottawa. Previous research led Stanford to discover the association between defects in MSC and age-related osteoporosis in mice.
The study’s co-author, John E. Davies, Ph.D., D.Sc., is a professor at the University of Toronto’s Institute of Biomaterials and Biomedical Engineering, The study’s findings are published in the current issue of Stem Cells Translational Medicine.
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.