Gene Therapy For Cystic Fibrosis

A novel form of gene therapy has been used to successfully treat mice with cystic fibrosis. The research – performed at the Laboratory for Molecular Virology and Gene Therapy at KU Leuven in Belgium – provided evidence that the therapy was also effective at treating cystic fibrosis in cell cultures taken from patients.

Cystic fibrosis – also known as mucoviscidosis – is a genetic disease that affects the mucus produced throughout the body. Patients with cystic fibrosis experience a thickening of the mucus in the lungs, which leads to clogging of the airways and difficulty breathing.

Currently, there are a few treatment options available to help patients manage their symptoms but there is no known cure of the disease. On a genetic level, cystic fibrosis is caused by mutations in the CFTR gene. This gene encodes a protein whose function is to channel water and chloride ions out of the cell.

Patients with cystic fibrosis have cells with either dysfunctional chloride channels, or no channels at all, which leads to the build-up of viscous mucus. “A few years ago, a new drug was launched that can repair dysfunctional chloride channels,” said Professor Zeger Debyser. “Unfortunately, this medicine only works in a minority of cystic fibrosis patients.”

“As for the impact of gene therapy, previous studies suggested that the treatment is safe, but largely ineffective for cystic fibrosis patients,” he said. “However, as gene therapy has recently proven successful for disorders such as hemophilia and congenital blindness, we wanted to re-examine its potential for cystic fibrosis.”

Lead authors of the study, Dragana Vidovi and Marianne Carlon developed an improved form of gene therapy in an attempt to more effectively treat cystic fibrosis. The researchers inserted a working copy of the CFTR gene into a non-pathogenic recombinant adeno-associated viral vector.

The virus containing the genetic information for functional chloride channels was then given to mice with cystic fibrosis, as well as cell cultures taken from cystic fibrosis patients. “We administered the rAAV to the mice via their airways,” said the researchers. “Most of the CF mice recovered. In the patient-derived cell cultures, chloride and fluid transport were restored.”

Though the results seem to show that the gene therapy was able to eliminate the disease in mice, the researchers warn that more experimentation with the virus must be performed before it can be used to treat human patients. “We must not give CF patients false hope,” they say.

“Developing a treatment based on gene therapy will take years of work. For one thing, our study did not involve actual human beings, only mice and patient-derived cell cultures. Furthermore, we still have to examine how long the therapy works. Repeated doses might be necessary. But gene therapy clearly is a promising candidate for further research towards a cure for cystic fibrosis.”

Sources:

• Gene Therapy: A Promising Candidate for Cystic Fibrosis Treatment – http://www.dddmag.com/news/2015/11/gene-therapy-promising-candidate-cystic-fibrosis-treatment