NEW ORLEANS -- Treatment with bone marrow mesenchymal cells, specialized bone-making cells, has the potential to enhance the therapeutic effects of bone marrow transplantation in patients with osteogenesis imperfecta, also known as brittle bone disease. The treatment, given to children at St. Jude Children's Research Hospital in Memphis, is based on groundbreaking research into adult stem cells done with Darwin Prockop at the Tulane Center for Gene Therapy in New Orleans. These findings are published in the June 25 issue of the journal "Proceedings of the National Academy of Sciences."

Mesenchymal cells are a distinct type of stem cells found in bone marrow that have the ability to form body tissues such as bone, cartilage, muscle and fat.

"This is the first human trial to clearly show the therapeutic potential of mesenchymal cells and represents a significant step forward in the development of cellular therapies, "said Edwin Horwitz, lead investigator for the research at St. Jude.

OI is a genetic disorder characterized by bones that break easily, often from little or no apparent cause. In 1983, Prockop and his team discovered the first of a series of genetic defects that decreases the production of collagen, the major protein of the body's connective tissue, to cause O.I. The disease can be mild to severe and affects between 20,000 and 50,000 Americans. Currently, there is no cure for OI.

Last year, the National Institutes of Health (NIH) awarded the Tulane Center for Gene Therapy more than $1.8 million for a five-year project to study replacing OI cells that have the defective gene with colonies of stem cells with the normal gene. The research also tests whether the stem cells are effective in overcoming the negative effects of the genetic mutations in collagen production that are associated with the disorder.

For the study reported in the journal today, five children with OI were given infusions of gene-marked, mesenchymal cells from bone marrow donors. The children, between the ages of two and five, had undergone standard bone marrow transplantation previously for severe OI. They received initial infusions of mesenchymal cells 18 to 34 months after bone marrow transplant. After a second infusion a few weeks later, all the patients showed engraftment in one or more sites including bone, skin and bone marrow.

"Also, the children who were extremely small and who either had stopped growing or were growing very slowly now began to grow very rapidly in that their rate of growth was 60 percent to 94 percent of the predicted growth rate of children unaffected by OI, "Prockop said.

For more information about the Tulane Center for Gene Therapy, go to: genetherapy.tulane.edu