Therapeutic Cloning Works in Mice With Parkinson's

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Therapeutic cloning is limited to the generation of a very early-stage embryo comprised of a small collection of undifferentiated stem cells. These malleable cells are then stimulated to develop into specified cells that could be reintroduced into the body of the original host to treat any number of diseases. Such an approach circumvents a patient's natural immune response.

Tabar and her Sloan-Kettering colleague Lorenz Studer joined researchers at the RIKEN Center for Developmental Biology in Kobe, Japan, to test the viability of therapeutic cloning in mice that had been induced to develop Parkinson's.

The research team extracted cells from the tail tips of each of 24 young mice and therapeutically cloned 187 distinct stem cell lines --including at least one DNA-specific line per mouse.

After inducing the stem cells to develop into dopamine neurons, each Parkinson's mouse was "treated" with the insertion of only those neurons derived from its own cells.

Subsequent behavioral tests revealed that this one-to-one therapeutic cloning technique significantly improved the neurological function of the mice without any adverse immune response. The observed improvement was found to be much better than that achieved by a group of control mice that were given dopamine cells cloned from a single mouse line, as in prior studies.

Compared with the one-to-one treated mice, the non-matched mice had poorer immune responses, poorer motor control improvements, and a mild degree of inflammation.

"It had been thought that this process would be way too cumbersome to carry out," said Tabar. "But this validates that it is feasible and superior to using non-matched genetic material."

Michael Jakowec, an assistant professor of neurology with the George and MaryLou Boone Parkinson's Disease and Movement Disorders Research Center at the University of Southern California Keck School of Medicine in Los Angeles, cautioned that the leap to humans might be "gigantic."

"You see a lot of failures in studies that try to translate success from rodents to humans," Jakowec said. "So, it may be premature to take this to human trial just yet. Perhaps it should first be replicated in primates. But it certainly does open up a new avenue of therapeutic strategy, which may ultimately benefit patients down the road."

More information

For more on Parkinson's treatment options, visit the National Parkinson Foundation.