Another alternative strategy to gene therapy is exon skipping which differs from gene therapy in that it focuses on the gene transcript rather than the gene itself (McClorey et al., 2005). Exon skipping prevents the transcription of the exon containing the mutation. Exon skipping is a process by which synthetic DNA molecules, antisense, are utilized to create a bridge by which the dysfunctional parts of the gene can be skipped over (Partridge, 2010). This intervention has been found to be particularly useful when treating Duchenne MD in laboratory animals and experts are hoping that this will correlate to human subjects as well.
Cell therapy has also shown promise in the treatment of MD. In this approach cells can be taken either from a donor that has healthy formations of the mutated gene or by utilizing repaired cells of the individual with MD (Cossu and Sampaolesi, 2004). The use of the individuals own genes has been made possible through the cloning process and these genes can then be introduced into the system of the MD patient. Recent studies have shown an 11% improvement in the positive muscle fibers surrounding the area of injection (Cossu and Sampaolesi, 2004). This approach is not without its challenges as well including the availability of donor cells as well as the failure of the donor cells to disperse throughout the muscle resulting in a concentration of cells in a particular area. Attempts to overcome this barrier have utilized stem cells and cells taken from bone marrow which have been proven to have regenerating factors in skeletal muscles (Cossu and Sampaolesi, 2004).
Pharmacological interventions have also shown promise in the treatment of MD these medications have primarily been utilized to stop the progression of the dystrophic process and have taken the form of protease inhibitors, anti-inflammatory drugs, calcium blockers and drugs that impact the metabolism of proteins and lipids (Cossu and Sampaolesi, 2004). Despite ongoing research, pharmacological interventions have not proven to be particularly effective in the reduction of symptomolgy producing only modest results in clinical trials (Cossu and Sampaolesi, 2004). However, there is data to suggest that the use of corticosteroid treatments can reduce the loss of ambulation by 2 to 4 years and will decrease the risk of the development of skeletal defects as well as slowing the onset of respiratory and cardiac issues (Cossu and Sampaolesi, 2004). Yet one must also pay attention to the potential negative side effects of these drugs and weigh this against the benefits.
Over the last decade, ongoing research and preclinical and clinical trials have produced new generations of interventions which will improve methods for efficient and long lasting improvements in the lives of those with MD. Advances have included not only the production of new viral vectors and improvements in exon skipping techniques but they have also led to the identification of various types of stem cells that can be utilized in future research and trials. It may also be the case that rather than one intervention that produces the cure for MD that a combination of pharmacology and aggressive treatments can truly address the consequences of gene mutation in MD. While gene based interventions can correct the mutations, pharmacology can prevent future damage and degeneration of muscular functioning.
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