Adult marrow cells show versatility, studies suggest

Certain bone marrow cells found in adults can be coaxed into forming a variety of specialized cells, says research that gives new hope for growing replacement body parts for treating disease.

It's not the only indication that certain cells from adults can form an array of cells for other parts of the body, but one expert called the new work promising. Another cautioned it's too soon to tell how useful it will be.

Much attention has focused lately on embryonic stem cells, unspecialized cells found in embryos that give rise to the widely varied tissue types of the body. One reason scientists are interested in them is to make replacement parts, like new brain cells for people with Parkinson's or new pancreatic cells to treat diabetes.

But using embryonic stem cells is controversial, because embryos must be destroyed to harvest them. So some researchers have turned to stem cells found in adults. Recent research has found these adult stem cells to be more versatile than scientists once thought, and the new research is continuing on that path.

Not yet published

Dr. Catherine Verfaillie and her colleagues at the Stem Cell Institute at the University of Minnesota have found that in a test tube, the marrow cells from humans can give rise to cells of bone, cartilage, fat and skeletal muscle, and to cells that resemble nerve and liver cells.

Most of the work has not yet been published in a scientific journal, but it has been submitted to journals, she said in a telephone interview.

Verfaillie noted that some other labs have said they've found cells with similar potential but have not published their results, so she can't compare her cells to theirs. In any case, it would be wrong to consider the cells she studies as some ultimate stem cell, she emphasized.

It's also too soon to tell whether her "multipotent adult progenitor cells" will be useful for treating disease, she said. And it's not yet clear whether these MAPCs will prove as versatile as embyronic stem cells, she said.

She and other stem cell experts said her findings should not be taken as a reason to stop studying embryonic stem cells.

'Best that's out there'

Dr. Diane Krause of Yale University, who last year reported mouse experiments that showed remarkable versatility for mouse marrow cells, called the new work "very, very promising."

It's "the best that's out there to date" on the versatility of adult cells, Krause said.

Krause noted that while her own work showed that mouse cells could produce a variety of cell types when implanted in a mouse, Verfaillie's results show scientists can make diversification happen in the laboratory.

She also said Verfaillie will have to show that the various cell types produced can function normally in the body. It's also not clear whether MAPCs exist naturally in the marrow, or whether they gain their properties in the laboratory, Krause said.

Dr. Irving Weissman of Stanford University, another expert on stem cells, said it's too soon to assess the importance of Verfaillie's work until it's published and verified by other laboratories.

"Nobody knows the real potential of these cells," he said.