How Can Genes Contribute to and Cure Congestive Heart Failure?
It is common knowledge that heart failure follows another severe form of heart damage; however, until now scientists and doctors have had no way to identify those at risk. New research into genes and gene therapy have made them a potential weapon in the fight against heart failure.
Scientists have made several discoveries regarding the role of genes in the detection and treatment of heart failure. Several years ago it was discovered that a small percentage of patients who had suffered heart failure possessed a defect in the gene that allows the body to detect stress signals; in essence, the heart does not know that it is working to hard and is unable to adjust. This percentage may seem insignificant; however, the gene mutation was not present in any of the healthy patients examined. Researchers stress that this is a susceptibility factor, not a cause of congestive heart failure; however, it may be the breaking point when determining if a heart suffering from other disease will fail. Detection of this mutation may allow doctors to identify and treat patients at risk prior to their heart failing rather than after.
This defect is found in the ATP-sensitive potassium channels and is caused by a genetic mutation. The potassium channel regulates potassium and calcium levels in the body. While the heart must have calcium to function, an excess of calcium leads to damage. This is the reason calcium blockers are often given to patients with congestive heart failure. Fortunately, medications to open the potassium channel already exist.
In addition, a defect of the delta-sarcoglycan gene has been seen in hamsters with muscular dystrophy and cardiomyopathy. This gene is the cytoskeleton of muscle fibers, and successful transplant of a normal human delta-sarcoglycan gene has been shown to cause a tremendous improvement in these animals. This is noteworthy because current transplant attempts require open heart surgery. This type of gene transplant is carried on a virus, eliminating the need for surgery.
Scientists had been a bit concerned with using this method of gene therapy due to the need for a systemic effect. There was also some concern that the body’s natural immune system would eliminate the virus of its own accord prior to successful delivery of the gene; however, they believe they have found the best form of virus to successfully slip past the body’s defenses. When transplanting the delta-sarcoglycan gene researchers used a type eight adeno-associated virus, piggybacking the corrective gene onto it as it was inserted into the body. This allowed the gene to be carried to all areas of the body in animals with muscular dystrophy without being destroyed by the body’s own natural immunity.
Gene therapy is still highly experimental, and researchers are unsure yet of the role it will play in the conquest of heart failure; however, this represents a technology that was unavailable thirty years ago. Continuing advancements in technology and medicine’s knowledge of the body’s building blocks may one day unlock the mysteries to the cure of this deadly disease.