New Hope for Muscular Dystrophy
Gene Therapy Effectively Treats Muscular Dystrophy in Dogs
By Meghan Kurz
Purpose of This Assignment
What is muscular dystrophy?
Genetics in the News
Gene Therapy Treatment Successful in Dogs with Muscular Dystrophy
Interestingly enough, it has been found that dogs can develop Duchenne Muscular Dystrophy (DMD) in the same fashion as the human body. Through the same alteration, deletion, or inactivity of dystrophin, canines are left with similar symptoms that are seen in boys with DMD. More than 10 years ago researchers were able to mimic dystrophin. However, dystrophin is one of the largest genes in the human (and canine) body, and it was impossible to transfer the created gene because it simply does not fit into a harmless virus or vector. A vector is defined as "any agent that acts as a carrier or transporter, as a virus or plasmid that conveys a genetically engineered DNA segment into a host cell. " (http://dictionary.reference.com/browse/vector) The therapy also needs to treat all muscles throughout the body, not just one single muscle or organ. This has also caused a set back.
For years, researchers at University of Missouri School of Medicine have worked to successfully creat a smaller, more compact version of the dystrophin gene (called an microgene). Previously, this microgene has successfully treated dystrophic mice. The most recent study has advanced to treating DMD in larger animals. "The research was funded in part by NIH’s National Heart, Lung, and Blood Institute (NHLBI). The study was published on October 15, 2015, in Human Molecular Genetics" (Torgan, Ph.D., 2015, paragraph 4).
Dr. Dongsheng Duan has lead a team at Missouri School of Medicine to deliver the gene therapy through a commonly used viral vector known as AAV-9. This viral vector does not create any symptoms or sickness in humans or canines. During their study, the researchers have delivered the dystrophin microgene through the vector to the blood stream of puppies with muscular dystrophy who have depressed immune systems.
The study found that the puppies tolerated the injections incredibly well. The gene therapy did not stunt growth at all. In addition, the researchers were able to detect dystrophin protein in several muscles in the puppies body, including the diaphragm, heart, and limbs for at least 4 months. The puppies' muscle tissue cells showed improvements as well. The dogs are now 6-8 months old and continue to develop within normal limitations.
There is still much to be researched, such as long term side effects and effectiveness in large mammals, but Duan says "This discovery took our research team more than 10 years, but we believe we are on the cusp of having a treatment for the disease” (Torgan, Ph.D., 2015, paragraph 7).
Why are These Findings Important to Nurses
Basi, C. (2015, October 22). Gene Therapy Treats All Muscles in the Body in Muscular Dystrophy Dogs; Human Clinical Trials are Next Step. Retrieved November 15, 2015, from http://munews.missouri.edu/news-releases/2015/1022-gene-therapy-treats-all-muscles-in-the-body-in-muscular-dystrophy-dogs-human-clinical-trials-are-next-step/
Torgan, Ph.D., C. (2015, November 2). Gene therapy treats muscular dystrophy in dogs | National Institutes of Health (NIH). Retrieved November 15, 2015, from http://www.nih.gov/news-events/nih-research-matters/gene-therapy-treats-muscular-dystrophy-dogs
Basi, C. (2015, October 23). Gene therapy treats muscular dystrophy in dogs - Futurity. Retrieved November 15, 2015, from http://www.futurity.org/duchenne-muscular-dystrophy-dogs-1032682-2/
Beery, T., & Workman, M. (2012). Genetics and genomics in nursing and health care (1st ed.). Philadelphia, Pennsylvania: F.A. Davis.
vector. (n.d.). The Free On-line Dictionary of Computing. Retrieved November 15, 2015, from Dictionary.com website: http://dictionary.reference.com/browse/vector