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Patent hints how firm may farm human tissue
Gareth Cook, Globe Staff, 7/26/2001
Despite a flurry of international interest, the company has revealed little about its plans to grow genetically matched human cells. But a patent application filed by the company outlines a bold new proposal: growing cells for human organs, such as hearts and livers, in the bodies of mice. Robert Lanza, a top scientist at Advanced Cell Technology and one of the patent's authors, said that tissue farming in mice might allow scientists to create types of specialized cells not possible with current methods. The technique would put to medical use a process in which the body's most primitive cells can form bizarre tumors, called tera tomas, filled with all kinds of tissues, even hair and teeth. The tumors could then be harvested and the cells a patient needs could be drawn out, grown, and transplanted. Lanza said that technique was only a research tool and that the company currently has no plans to test mouse-grown cells in humans. "This is just one of many possibilities we are exploring," he said. As the federal government considers new restrictions on engineering human tissues, the Worcester firm's patent application, filed in September, gives a rare look inside a company at the forefront of such work. "Scientists are very curious about what is going on in the company," said George Daley, a fellow at the Whitehead Institute in Cambridge, one of the nation's top biology research institutions. Researchers have already used mice to grow human tissue, including a famous experiment at Massachusetts General Hospital in which a human ear was grown on the back of a mouse. What the Advanced Cell Technology patent proposes, however, is to use these mice in stem cell research, one of the hottest, most controversial, and potentially most lucrative areas of biological research. Stem cells are primitive cells that have the ability to grow into a variety of different body tissues. Researchers have been able to isolate stem cells for several years and are now trying to find ways to coax them into differentiating into the specific cells needed to treat disease, for example, an insulin-producing cell for a diabetic. Solving this problem would make possible a world of new medical treatments. If scientists are unable to develop techniques for creating a particular type of cell, another approach is to encourage the stem cells to proliferate wildly into many cell types and find ways to harvest the ones of interest. Injecting human stem cells into an immune- compromised mouse results in a growth of mixed human tissues that lives like a parasite inside the mouse. But some scientists are skeptical about the idea, outlined in the patent, of removing these tissues from a mouse and using them in patients. "This looks like a laborious way to do it," said Rudolf Jaenisch, a cloning specialist and a biologist at the Whitehead Institute in Cambridge. "It would be difficult to clean out the unwanted cells." The plan would also raise a host of ethical questions. Ronald Green, who serves as the chairman of the independent ethical advisory board set up by Advanced Cell Technology, said that the company would need to consider the welfare of the animals used as hosts and demonstrate that the process wouldn't bring deadly animal viruses into the human population. Green said that Michael West, the firm's president, referred to the possibility of growing human cells in animals during a July 9 meeting in which he briefed the ethical board on the company's future research directions. Advanced Cell Technology is best known for its work in animal cloning, including an attempt to clone a guar, a member of an endangered species, earlier this year. The thrust of the firm's human-cell research, Lanza said, is to find ways to repair damage to heart, nerve, liver, and other cells, in order to treat such maladies as Parkinson's disease and heart disease. The vast majority of the company's research focuses on animals, he said, as a way to understand basic processes so they can be applied to human medicine. One of the central obstacles to successful organ transplants and tissue repair is immune rejection, the body's natural tendency to attack material it considers foreign. Advanced Cell Technology hopes to avoid such rejection by using cloning techniques to generate tissue with the same genetic makeup as the patient. The patent for the new tissue-farming technique, titled "Method for generating immune-compatible cells and tissues using nuclear transfer techniques," describes an experiment in which a cow cell was cloned and then used to grow a teratoma in mice. The teratoma was then removed, and the experimenters grew several kinds of tissue from cells in the teratoma, including muscle, kidney, and skin. When such tissues were placed back into the cow, researchers were surprised to find there were no immune rejection problems. The patent was first filed as a provisional patent in September 1999, and the official patent application was filed in September 2000. It is common for companies to file a provisional application as a way of protecting their ideas, before filing the application that begins the patent process in earnest, said Ingrid A. Beattie, a biotech patent specialist and senior associate with the law firm Mintz Levin in Boston. Lanza said it is one of the company's 160 patents and patent applications. Most of that number comprises patent applications. Only the company's patent applications that were also filed abroad are currently available to the public, typically 6 months after the full application.
Gareth Cook can be reached by e-mail at cook@globe.com.
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© Copyright 2001 Globe Newspaper Co. |
Profile: 
dvanced Cell Technology, the Worcester company that announced it will
clone and harvest human cells, has kept remarkably quiet since disclosing the
project two weeks ago.