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Gentamicin administration in Duchenne patients with premature stop codon. Preliminary results
1Department of Clinical and Experimental Medicine and Surgery, Section of Cardiomyology and Medical Genetics, 2nd University of Naples, Italy. luisa.politano@unina2.it
Abstract:
Aim of the study was to investigate whether the administration of gentamicin could restore dystrophin expression in striated muscles of patients with Duchenne muscular dystrophy caused by premature stop codon, as reported in mdx mice. Four Duchenne patients, still ambulant or in wheelchair stage for less than 4 months, selected among those with point mutations resulting in premature stop codons, received two 6-day cycles of gentamicin sulfate, at an interval of 7 weeks, according to the protocol approved by the Ethics Committee of the Second University of Naples. A muscle biopsy was performed after the second cycle of administration; the specimens were analysed by both immuno-histochemistry and Western blotting. Skeletal muscle changes were monitored by dynamic tests and Creatine Kinase values; at the beginning and end of treatment, cardiac and respiratory status was evaluated by electrocardiography, echocardiography, acoustic densitometry and vital capacity. Side-effects such as nephrotoxicity and ototoxicity were also monitored. Three out of four patients, who had the most permissive UGA as stop codon, showed positive results. In one patient, there was a dramatic re-expression of dystrophin by both immuno-histochemistry and Western blot; in two patients, dystrophin positive fibres were seen by the antibody to the rod domain with immuno-histochemistry; the fourth patient, with UAA as stop codon, showed no expression of dystrophin at all. These results suggest that gentamicin is able to recover dystrophin expression in a subset of Duchenne patients with nonsense mutations, raising the possibility of the first pharmacological treatment for muscular dystrophy.
Insights
Gentamicin treatment showed potential in restoring dystrophin expression in some Duchenne muscular dystrophy patients with premature stop codons. This suggests a possible first pharmacological therapy for this genetic muscle-wasting disease.
Area of Science:
- Genetics
- Pharmacology
- Neurology
Background:
- Duchenne muscular dystrophy (DMD) is a severe genetic disorder characterized by progressive muscle degeneration.
- Nonsense mutations, leading to premature stop codons, are a significant cause of DMD.
- Current treatments for DMD are limited, highlighting the need for novel therapeutic strategies.
Purpose of the Study:
- To investigate the efficacy of gentamicin in restoring dystrophin expression in DMD patients with premature stop codons.
- To evaluate the safety and tolerability of gentamicin treatment in this patient population.
Main Methods:
- Four DMD patients with premature stop codons received two cycles of gentamicin sulfate.
- Muscle biopsies were analyzed using immunohistochemistry and Western blotting to assess dystrophin expression.
- Skeletal muscle function, cardiac and respiratory status, and potential side effects were monitored throughout the study.
Main Results:
- Three out of four patients exhibited positive results, with one showing dramatic dystrophin re-expression.
- Dystrophin-positive fibers were observed in two patients via immunohistochemistry.
- The fourth patient, with a different type of stop codon, showed no dystrophin expression.
- Gentamicin was generally well-tolerated, with nephrotoxicity and ototoxicity monitored.
Conclusions:
- Gentamicin can restore dystrophin expression in a subset of Duchenne muscular dystrophy patients with specific nonsense mutations.
- This finding offers a potential first pharmacological treatment for DMD, particularly for patients with amenable stop codons.
- Further research is warranted to optimize gentamicin-based therapies for Duchenne muscular dystrophy.