Massachusetts company claims to have built working kidneys from cloned embryos
Thursday, January 31st 2002, 12:00 am
News On 6
BOSTON (AP) _ Using building material from cloned cow embryos, scientists say they have constructed miniature kidneys that appear to function similar to genuine organs.
While it is still unclear whether these made-from-scratch kidneys can perform all the duties of the ordinary variety, the researchers said they work well enough to produce urine.
The research was done by Advanced Cell Technology in Worcester, Mass., the same company that caused an uproar in November with the announcement that it had taken steps toward human cloning.
The latest research has not been published in a scientific journal, so experts said they found it difficult to assess the importance of the company's claim.
``It's within the real of possibility that it could be done,'' said Dr. George Q. Daley, a stem cell expert at the Whitehead Institute in Cambridge, Mass. ``It's one of the more provocative pieces of news that I've heard from this whole area. We can't evaluate the claim without seeing the data.''
The ultimate goal of the research is to find replacement parts for worn out or damaged human organs, starting with cells from test-tube embryos that are genetic twins of the recipient.
Scientists hope eventually to construct new organs that are genetically identical to the recipient's own body. This would eliminate the need for ordinary transplants and avoid the use of drugs to prevent rejection of the new organ.
``There are many, many years of work ahead of us,'' Dr. Robert P. Lanza, the scientist in charge of the project, said Wednesday. ``These are exciting but very preliminary data.''
The company's accomplishment was reported in Wednesday's Washington Post. Lanza said he released the data to the Post to correct errors in articles published Tuesday by London newspapers on the work. He said the research is being written up for publication in a journal.
Lanza said the researchers started with a skin cell taken from the ear of an adult cow. The scientists removed the genetic material from an egg taken from another cow and replaced it with genes from the skin cell. This grew into a cow embryo.
Embryos contain master cells called stem cells that have the potential to grow into any tissue in the body. In this case, they grew the embryos to the stage where they could identify cells destined to become kidney cells.
Then, working with researchers from Children's Hospital in Boston, they placed these immature cells on a two-inch-long support structure that looked like a sponge. The cells grew on the structure and took on the function of a kidney.
Lanza said they implanted several of these under the skin of the cow that donated the original skin cell. There they produced urine that collected into synthetic bags hooked up by the scientists.
Producing embryos this way to serve as sources of cells is called therapeutic cloning. Many are ethically opposed to such work in people, even though the aim is to produce cells, not a complete human being.
``Our goal is to not only generate individual cells, such as insulin producing cells, but also to reconstitute them into more complex tissues and structures, such as kidneys or complete hearts,'' Lanza said.
He said the company chose to do the experiment with a cow instead of a mouse, which is a more standard lab subject, because ``the cow is a large animal with a sophisticated immune system similar to a human's.''