Stem cell therapy holds great promise for various diseases. In fact, in what many are hailing as a medical milestone, European researchers have successfully transplanted a trachea built from a patient’s own stem cells to replace a failing airway damaged by tuberculosis, according to a recent article in The Lancet.
The team stripped a donor trachea of all its cells and used the remaining collagen as a scaffold that was seeded with the patient’s stem cells. Four days after surgery, the engineered windpipe was almost indistinguishable from normal bronchi; four months post-surgery, the patient shows no signs of rejection and is enjoying a normal quality of life.
This success may help future stem cell applications overcome some of the current challenges, which speakers at the “Stem Cell Summit” to be held next month, talked to GEN about in advance of the meeting. The scientists interviewed for this article were especially concerned about regulatory issues—is it a device, biologic, or both; financial matters—it’s an early field and federal funding for embryonic stem cell research has been put on hold; quality and quantity assurance of stem cells to enhance patient outcomes; and understanding their mechanism of action.
Despite the challenges, however, a recent BBC Research market report (July 2008) estimates the U.S. market for stem cell technology is expected to increase from $112 million in 2007 to $423 million in 2012.
Since the 1970s, Stuart Williams, Ph.D, CSO at Tissue Genesis, has been experimenting with isolating cells from fat to test their potential use in building blood vessels. The resulting mix of adult stem cells has regenerative qualities. “I started using these cells in lab experiments and learned how to isolate them. I realized this type of therapy needed to be automated in a totally closed system.”
This conclusion led to the development of the company’s TG1 1000 cell isolation system. The compact desktop unit provides isolated cells in about an hour, according to the company, and accepts fat tissue from the same device used for tissue harvesting.
Dr. Williams explains that the most critical component of the process is the company’s enzyme mixture to digest tissue and keep the cells viable. Initial efforts involved using the cells to reline artificial blood vessels. His group took Gortex-like tubing commonly used in vascular procedures and lined the inner surface with the patient’s own cells derived from fat, which re-created the natural blood vessel lining rapidly after the implant.
“We only need about 30 grams of fat for vascular grafts. Each gram provides about a million therapeutic cells and is consistent from patient to patient,” explains Dr. Williams. The stromal cells take cues from the extracellular matrix proteins they are surrounded with. So if they are removed from fat and placed in a new environment, like the heart, they will take their cues from heart tissue. “You can put them in a 2-D or 3-D environment and the matrix will have a dramatic effect on their phenotype and function.”
The company has set up a consortium that explores these cells for orthopedic (spinal fusions), cardiac (congestive heart failure, myocardial infarction), and inflammation (currently for veterinarian use only) applications.
Dr. Williams says that they are now working with the FDA to gain approval of the device for specific therapeutic applications. “The device itself is just a complex centrifuge digestion system. What you use the cells for will dictate within FDA regulations whether it will go through an IDE process or an IND process and whether it will be registered as a biologic or a combination product.”