NEW YORK, Nov 16 (Reuters Health) - Stem cells collected from bone marrow can be naturally transformed into healthy liver cells that have the ability to repopulate damaged areas of the liver, according to results of a study in mice.

The mice used in the study lack an enzyme called FAH and develop progressive liver failure and die unless treated with a chemical known as NTBC. When such mice underwent a transplant with stem cells from the marrow of normal mice, four of nine mice survived, and all four showed donor cells that had developed into normal liver cells repopulating their diseased livers, the researchers report.

The donor cells that became healthy liver cells derived from stems cells found in the marrow, which are primitive cells that can give rise to all cells in the blood and immune system. As few as 50 of the stem cells--known as hematopoietic stem cells--were able to replenish not only blood cells but also liver cells in the mutant mice, the report indicates.

The study, conducted by Dr. Markus Grompe from the Oregon Health Sciences University in Portland, and Eric Lagasse from StemCells, Inc. in Sunnyvale, California along with colleagues there and elsewhere, is published in the November issue of the journal Nature Medicine.

"These studies in the mouse provide preclinical evidence that perhaps purified human hematopoietic stem cells may similarly be a source of (liver cells) for therapeutic liver repopulation in the appropriate conditions," the authors conclude.

"Turning stem cells into 'therapeutic gold' will probably rest on our ability to identify the mechanisms by which tissue-derived stem cells respond to environmental cues and execute new developmental decisions," writes Stuart Orkin from Harvard Medical School in Boston, Massachusetts, in a related commentary.

"Although the full developmental potential of tissue stem cells remains to be discovered," Orkin states, "we can be sure of one thing: More surprises undoubtedly await stem cell researchers."

(From Reuters)