Researchers at two universities have demonstrated thefeasibility of using immature muscle cells as the deliveryvehicle for gene therapy.
Working with rodents, teams at Stanford and the University ofMichigan, Ann Arbor, showed that myoblast cells from acultured cell line can be engineered to make human growthhormone. Injected into an animal's muscle, the myoblastsincorporated into the tissue and supplied the hormone to thebloodstream for at least three months in physiologicallyrelevant amounts.
The Stanford researchers have started Phase I clinical testingof the myoblast transfer technique to treat Duchenne'smuscular dystrophy.
Uncertainties remain, however. As a cell line, the myoblastshave the potential to form tumors, though none were detectedin the course of the two experiments.
Also, immune suppression was required in the Stanfordexperiments if the mice were not immunologically matched tothe myoblasts. The Michigan researchers found that immunesuppression was not necessary in a test they conducted withfour rats, who did not reject the tissue for at least three weeks.
The Michigan group suggested that humans could donate theirown muscle cells to be altered and then replaced. However, incomments accompanying the reports last week in Science,Inder Verma of the Salk Institute in La Jolla, Calif., suggestedthat primary myoblasts may not be as easily engineered as thelab-grown versions.
Vical Inc. of San Diego has pursued direct injection of genesinto muscle cells, yet this approach has not yet achieved theefficiency of myoblast transfer, researcher Helen Blau noted inthe Stanford report.
On the other hand, Blau's mouse technique has yet to proveitself in humans, where the transfer may not work as well, saidMcGill University's George Karpati in the accompanyingcomments.
Blau told BioWorld she has been talking to companies aboutcommercializing the application.
-- Roberta Friedman, Ph.D. Special to BioWorld
(c) 1997 American Health Consultants. All rights reserved.