Dec. 21, 2009 -- A new type of gene therapy may help stop the progression of emphysema in young people who have an inherited form of the deadly disease.
Researchers say previous attempts to correct the gene mutation that predisposes young people to emphysema have failed to achieve lasting results.
But a new study shows a different approach that targets cells known as alveolar macrophages to deliver the gene therapy to the lungs of mice with this form of inherited emphysema was successful in treating the condition for two years.
Emphysema is a progressive lung disease that causes severe shortness of breath. There is no cure for the disease.
People born with a genetic mutation that causes a deficiency in alpha-1 antitrypsin are predisposed to an early form of emphysema as well as cirrhosis of the liver.
Researchers say this single gene defect makes the condition an ideal candidate for gene therapy, which would replace the defective gene with a normal one. But the problem until now has been finding the right cell in which to transfer the gene and deliver it to the lung.
In the study, published in the Journal of Clinical Investigation, researchers developed a system to target alveolar macrophage (AM) cells within the lungs of mice with alpha-1 antitrypsin deficiency. AM cells play a key role in the development of emphysema.
The results showed a single treatment of the gene therapy successfully delivered healthy human alpha-1 antitrypsin genes to 70% of the AM cells in the mice.
"The lung macrophages carrying the therapeutic gene survived in the lungs' air sacks for the two-year lifetime of the treated mice," says researcher Darrell Kotton, MD, associate professor of medicine and pathology at the Boston University School of Medicine, in a news release.
As a result, researchers say the symptoms and progression of emphysema in mice that received the gene therapy were significantly improved compared with untreated mice.