Gene Therapy was first tested on humans in the 1990s and since then we’ve heard claims about it being a miracle cure for diseases from Parkinson’s to AIDS. Despite the initial enthusiasm, very few patients have actually received this type of treatment, but the FDA has just approved the sale of the first targeted gene therapy in the United States aimed at a form of childhood leukemia.
What is Gene Therapy?
The basic concept of gene therapy is to replace missing or defective genes with normal genes. This is typically accomplished by using a virus to carry the normal genes into the cells.
Scientific American describes it this way, “The treatment, which was first tested in humans in 1990, can be performed inside or outside of the body. When it’s done inside the body, doctors may inject the virus carrying the gene in question directly into the part of the body that has defective cells. This is useful when only certain populations of cells need to be “fixed.” For example, researchers are using it to try to treat Parkinson’s disease, because only part of the brain must be targeted. This approach is also being used to treat eye diseases and hemophilia, an inherited disease that leads to a high risk for excess bleeding, even from minor cuts.”
The huge promise of gene therapy treatments was dampened in early research due to safety issues with the viral delivery of gene material to the cells.
How Can Gene Therapy Be Used for Hearing Loss?
Due to improvements in viral delivery methods over decades, gene therapy research is growing again in popularity. A few recent studies are focusing on hearing loss with some tests in mice showing great promise. With hearing loss affecting around 360 million people across the globe, this new focus is critical.
Several studies conducted by institutions including Johns Hopkins University, Columbia University, and The University of Kansas, are focusing on one specific area to target for hearing loss treatment: hair cells of the inner ear. Hair cells are the sensory receptors for all vertebrates. They’re located in the inner ear and come in two varieties, outer and inner. The outer hair cells amplify sound and the inner hair cells turn sound vibrations into electrical impulses to be sent to the brain. Exposure to loud noises, age, and certain prescription drugs can damage hair cells. Damage to either type of hair cells causes hearing loss and cannot be reversed. Ear hair cells do not regenerate.
Many causes of deafness result from the death of hair cells. The ability to trigger regeneration by delivering replacement parts directly to the hair cells could be the key to addressing hearing loss caused by damaged hair cells. However, it is important to note that research in this area is in very early stages and it will be years before clinical trials can begin.
Since hair cells are not the only cause of hearing loss, other research is focusing on genetic causes of hearing loss. The hope is to find treatments based on the identification of gene mutations responsible for the loss of hearing.
While gene therapy treatments are still years away, there are many current treatments that will improve the quality of life for anyone living with hearing loss. Schedule an appointment with us to discuss the best option for you.
