The field of stem cell research is progressing rapidly despite technical and policy challenges. In fact, the global stem cell market is estimated to reach $88.3 billion by 2014, with the U.S. holding 60% of the market, according to a 2009 report from Bharat Book Bureau.
Although U.S. embryonic stem cell research guidelines have been relaxed since President Obama’s Executive Order this past July, several states (South Dakota, Louisiana, Arizona, Texas, and Oklahoma) are trying to restrict or altogether ban these efforts. In addition, there is still no federal law that prohibits reproductive cloning in the U.S.
In the U.K., however, such guidelines were established in 1990 via the Human Fertilization and Embryology Authority (HFEA). This group grants research licenses to individuals applying to use human embryos and regulates all clinics performing reproductive medicine. In 2001, its permission guidelines for embryonic research were expanded to include efforts under way to better understand human development and disease and to create new therapies.
Stephen Minger, Ph.D., former professor and director of the stem cell biology lab at King’s College, London, was the first researcher to obtain an HFEA license under these guidelines and reportedly the first to generate a human embryonic stem cell line in the U.K. Currently head of R&D for cell technologies at GE Healthcare, Dr. Minger’s academic work focused on developing cell therapy for diseases like multiple sclerosis, heart failure, and retinal disorders. The group utilized embryos with genetic mutations to develop cell lines in order to study the molecular basis of diseases.
According to Dr. Minger, this approach has advanced induced pluripotent stem cells (iPSC), allowing the creation of disease-specific cell lines from anyone with a known genetic mutation. “This opens up a whole new arsenal of approaches we didn’t have before and is moving research away from animal models and more into cell-based human models,” he reported at Select Biosciences’ “Stem Cells Europe,” meeting, which was held recently in Edinburgh.
Dr. Minger said that, although stem cell research is a young field, there has been a lot of progress academically and commercially growing cells under better conditions and to greater scale. “We probably still don’t have optimal growth conditions and differentiation protocols are still under development.”
Questions remain as to whether it’s possible to generate cells of high enough purity and quality for drug screening or predictive toxicology. “What purity do cells have to be to constitute a good clinical product? Is 95% acceptable if you know what the other 5% are?”
Questions also remain regarding clinical development. “We need to develop automated systems and technology to monitor the cells, to be able to grow the trillions of cells required to take cell therapy into real clinical practice. It’s impossible to say we’ll be there in two years or ten years. We still have quite a long way to go.”
GE Healthcare and Geron entered into a global license and collaboration agreement in June 2009 to develop and commercialize cellular assay products derived from human embryonic stem cells for use in drug discovery, development, and toxicity screening.
Researchers at the University of Bristol have developed a tissue-engineering method to effectively take stem cells from bone marrow and, using the right growth factors, drive cartilage cell formation. Several challenges remain, reported Anthony Hollander, Ph.D., professor of rheumatology and tissue engineering. Since the patients are not life-threatened but in pain, and perhaps somewhat disabled, the burden of evidence that stem cell therapy is going to be safe and effective is much higher. Cost is another factor. “Although we’re using the patient’s own cells and there is no immune rejection, it’s personalized medicine and very expensive.”
Dr. Hollander’s research is focused in two main areas. The first is growing cartilage from adult stem cells to treat osteoarthritis in aging individuals. It takes approximately 48 hours to turn adult stem cells into cartilage cells, compared to five weeks to create a piece of cartilage from tissue culture. This is a long way from clinical applications, he added, because they still have to discover how to grow large pieces of cartilage and how to integrate them with the surrounding natural cartilage in the joint.
Another research area is repairing torn meniscal cartilage, the semicircular cartilage pieces in the knee that act as shock absorbers. In most cases, the only treatment is surgery, which later increases the risk of osteoarthritis. Dr. Hollander’s group has developed a stem cell bandage for which stem cells are taken from the patient’s bone marrow and grown in culture. These are kept on a scaffold as undifferentiated stem cells until they reach the required amount.
“We place these cells in the middle of the torn meniscus and sew it up around the cell bandage. The idea, and we’ve shown this in the lab, is that the stem cells migrate between the two surfaces and literally knit across the surface, causing an integration.”
A spin-out company, Azellon Cell Therapy, has been created to market the Cell Bandage, which is currently being tested in sheep. According to Dr. Hollander, the company has funding for a safety study to start next year in 10 patients. The next big step, he said, is to scale up these techniques, to increase implant size and develop a donated cell method in order to use cell lines to treat large numbers of patients.