In what could be a major setback to regenerative medicine, researchers have found that cells harvested and reprogrammed to perform like embryonic stem cells could fail to do the magic.

Cells from adult skin or body tissue when reprogrammed into potential stem cells, may not work as the cells from human embryos do, says a study conducted by scientists at Harvard University.

The researchers found that the induced or reprogrammed adult stem cells, or IPS cells, retain a “memory” of their original tissue. This makes it more difficult to convert them into other cell types useful to treat medical conditions, according to the report authored by scientists at Harvard University and Johns Hopkins University and published online in the scientific journal Nature.

Till now, the stem cell scientists were under the impression that reprogrammed adult body cells have the ability to grow into all tissue types in the body and could be substituted for embryonic stem cells. Once substituted, they will grow into all tissue types in the body.

Different IPS cells are currently undergoing studies to evaluate their efficacy in diseases like Parkinson's and diabetes. The findings in the new study may pose a challenge to these studies, experts say.

“It’s a challenge to be understood and overcome,” George Daley, a researcher at the Harvard Stem Cell Institute and Children’s Hospital in Boston and lead author of the Nature study, “We already have strategies for overcoming this.”

The researchers, however, are trying to find out ways to get around the limits of reprogrammed stem cells. The new findings may even alter the course stem cell medicine, which is often touted as the new age therapy providing answers for a whole lot of diseases and conditions with no known cure.

Stem cell-based regenerative medicine also aims to grow human tissues and organ in the lab to repair or replace damaged body parts. “These findings cut across all clinical applications people are pursuing and whatever diseases they are modelling,” Daley said.