Stem cell breakthrough

Jun 14 2006

Researchers at The Hospital for Sick Children (SickKids) and the University of Calgary have found that stem cells derived from adult skin can create neural cell types that can be transplanted into and function in mouse models of disease.

This research is reported in the June 14, 2006 issue of The Journal of Neuroscience.

SickKids researchers previously discovered what type of cells can be made from these stem cells (called skin-derived precursors, or SKPs) based on the role played by neural-crest stem cells during embryogenesis. In addition to generating the peripheral nervous system, neural crest stem cells generate other tissues such as bone, cartilage, some types of muscle, and even part of the heart.

In The Journal of Neuroscience paper, the research team found that SKPs can efficiently generate a type of glial cell, called Schwann cells, that can myelinate demyelinated axons (part of a neuron), and that have been shown to provide a good growth environment for injured central nervous system axons. These types of axons normally do not regenerate.

"Schwann cells have been proposed as a cell type for treatment of nerve injuries, demyelination disorders such as multiple sclerosis, and even spinal cord injury," said Dr. Freda Miller, the study's principal investigator, a senior scientist in Developmental Biology in the SickKids Research Institute, a professor of Molecular and Medical Genetics, and Physiology at the University of Toronto and Canada Research Chair in Developmental Neurobiology. "Our finding that we can efficiently generate and isolate these Schwann cells from SKPs raises the possibility that we could treat humans with Schwann cells derived from human skin stem cells, and perhaps even use the patient's own skin to generate Schwann cells for treatment."

The research showed that these SKP-derived Schwann cells can myelinate axons in culture, in the injured peripheral nerve, and even in the central nervous systems of mice that don't have myelin in their brains. While the research occurred in mouse models, some of their data indicate that human SKPs can do the same thing.

"Previous work has only dealt with SKPs in culture and their more basic biology. Now we have shown that SKPs can make at least one cell type that functions as predicted in animals," said Dr. Rajiv Midha, study author, a scientist at the Hotchkiss Brain Institute as well as chairman of the Division of Neurosurgery and professor and deputy head in the Department of Clinical Neurosciences at the University of Calgary. "This is the first time SKPs have been demonstrated to make bona fide neural cell types that can be transplanted into and function in animal models of disease."

Other members of the research team included Drs. Ian McKenzie, Jeff Biernaskie and Jean Toma, all from SickKids.

The next steps for the research team are to perform similar functional studies for the other cell types that they have shown are made by SKPs, including nerve cells, and to ask whether these SKP-derived Schwann cells can function in situations of human nervous system disease, such as spinal cord injury. On the basis of their findings, Dr. Miller and Dr. Wolfram Tetzlaff at the University of British Columbia have obtained a $1.5 million team grant from NeuroScience Canada's Brain Repair Program to determine whether human SKPs can be used to repair the injured spinal cord in rodents. The mission of NeuroScience Canada's Brain Repair Program is to fast-track neuroscience research in order to develop treatments and therapies more quickly.