Never mind Wednesday’s presidential veto on expanded federal funding of stem cell lines. Stem cell research is alive and well at a host of small companies and academic laboratories in the United States.
In Irvine, Calif., a tiny company called PrimeCell Therapeutics has taken adult stem cells found in testes, reprogrammed them, and created human heart, brain, bone and cartilage cells. This marks a breakthrough in developing what are known as “pluripotent” adult stem cells–cells that can be turned into most other cell types. That pluripotent ability, and the fact that stem cells self-renew, is the main attraction of stem cells from human embryos. One challenge with embryonic stem cells, however, is preventing them from creating tumor cells. So far, the PrimeCell researchers have been able to reprogram the cells they extract from testes without any tumor growth.
Plenty of other firms are active in the stem cell field. Stemnion, a small biotech firm in Pittsburgh, is working on using stem cells found in the placenta for healing wounds. Cellerant Therapeutics of San Carlos, Calif., will soon start a human trial using highly purified adult stem cells found in bone marrow to treat patients with Sickle Cell disease, a genetic blood disorder. Osiris Therapeutics of Baltimore has several trials under way using adult stem cells to treat the intestinal inflammation known as Crohn’s disease, repair damaged tissue following a heart attack and prevent the progression of arthritis. And Geron of Menlo Park, Calif. is performing animal studies on a variety of different cells derived from human embryonic stem cells, aiming to treat spinal cord injury, heart disease and diabetes.
Outside the U.S., adult stem cells have been used to treat patients with Type 2 diabetes in Argentina, heart disease in countries including Germany, Thailand and India, and babies with malformed hearts in Japan. Success rates among these treatments are all at least 68% or higher. For the diabetics treated in Argentina, more than two-thirds were able to stop taking insulin and diabetes medications following the stem cell treatment.
“There’s an incredible amount of research and a very large sum of venture capital and private investment going into the field,” says Dr. Amit Patel, a cardiac surgeon and director of Cardiac Cell Therapy at the University of Pittsburgh Medical Center. Patel has been called by venture capital firms to consult on potential investments. Bush’s veto of the stem cell bill on Wednesday “may slow down embryonic stem cell research” adds Patel, but he’s optimistic that research will continue nonetheless with private funding. Adult stem cell research will be unaffected.
Patel has pioneered the use of adult stem cells to treat heart disease. He worked with surgeons in Thailand last December to treat Hawaiian singer Don Ho. Ho’s own blood-derived adult stem cells were injected into his heart to treat heart failure. Ho’s health has improved so much that he has returned to performing.
Patel is particularly impressed with the work done by PrimeCell using what are called “germ line” stem cells–cells that will turn into sperm. Patel says he divides stem cells into thrift-store cells and designer cells. “PrimeCell’s cells are like the Prada of cells. They’ve taken an adult cell and reprogrammed it,” he says. “The potential of their cells is incredible.” One advantage of these cells is that they do not age as a human ages.
A group of German researchers replicated PrimeCell’s proof of concept in mice, and published the results in Nature in March. But PrimeCell appears to be ahead of the German team because it’s already moved from mice to human cells. PrimeCell has $10 million in private funding from two sources: an unnamed investor and Thomas Yuen, chairman and chief executive of PrimeCell’s parent company, PrimeGen.
Large pharmaceutical companies such as Pfizer and Merck have so far steered clear of stem cell therapy. For historical reasons, Novartis owns a small stake in Cellerant. Big pharma “is letting the smaller companies work and realize the potential. Now is the time for small, nimble entities,” says Dr. Hans Keirstead, an associate professor at the Reeve-Irvine Research Center at the University of California at Irvine.
Keirstead is working with human embryonic stem cells to treat spinal cord injury. He has received funding for his lab from Geron, which has an exclusive license of Keirstead’s patents and aims to start human trials on spinal cord injury as soon as next year.
Lost in the news of Bush’s veto of stem cell bill was the fate of a separate bill sponsored by Sen. Rick Santorum (R-PA) and Sen. Arlen Specter (R-PA) to encourage the National Institutes of Health to fund research of stem cells that are not embryonic. The Santorum/Specter bill passed the Senate but did not get the two-thirds vote needed in the House on Tuesday.
Kerry A. Dolan