Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0235394 (wasting)
 8,040 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Duchenne muscular dystrophy (DMD), a severe muscle wasting disease of young boys with an incidence of one in every 3000, results from a mutation in the gene that encodes dystrophin. The absence of dystrophin expression in skeletal muscles and heart results in the degeneration of muscle fibres and, consequently, severe muscle weakness and wasting. The mdx mouse discovered in 1984, with some adjustments for differences, has proven to be an invaluable model for scientific investigations of dystrophy. 2. The development of the diaphagm strip preparation provided an ideal experimental model for investigations of skeletal muscle impairments in structure and function induced by interactions of disease- and age-related factors. Unlike the limb muscles of the mdx mouse, which show adaptive changes in structure and function, the diaphragm strip preparation reflects accurately the deterioration in muscle structure and function observed in boys with DMD. 3. The advent of sophisticated servo motors and force transducers interfaced with state-of-the-art software packages to drive complex experimental designs during the 1990s greatly enhanced the capability of the mdx mouse and the diaphragm strip preparation to evaluate more accurately the impact of the disease on the structure-function relationships throughout the life span of the mouse. 4. Finally, during the 1990s and through the early years of the 21st century, many promising, sophisticated genetic techniques have been designed to ameliorate the devastating impact of muscular dystrophy on the structure and function of skeletal muscles. During this period of rapid development of promising genetic therapies, the combination of the mdx mouse and the diaphragm strip preparation has provided an ideal model for the evaluation of the success, or failure, of these genetic techniques to improve dystrophic muscle structure, function or both. With the 2 year life span of the mdx mouse, the impact of age-related effects can be studied in this model.
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PMID:Diaphragm muscle strip preparation for evaluation of gene therapies in mdx mice. 1821 82

Restoring dystrophin expression in the muscles of patients with Duchenne muscular dystrophy (DMD) may halt or reverse the degenerative wasting and weakness that causes premature death. However, the therapeutic efficacy of an intervention may be limited by the extent of disease progression prior to treatment. In this study, we considered the potential for ameliorating the pathology in a mouse model of advanced-stage muscular dystrophy by systemic administration of recombinant adeno-associated viral (rAAV6) vectors encoding a microdystrophin expression construct. The treatment of 20-month-old mdx mice restored body-wide expression of a dystrophin-based protein in striated musculature. In aged mice that received treatment, the resultant dystrophin expression was associated with improved hindlimb and respiratory muscle morphology and function, concomitant with reduced muscle fiber degeneration. The findings demonstrate that an established dystrophic state remains amenable to improvement with appropriate intervention and, by some measures, may even achieve benefits similar to those observed with intervention early in disease progression. The capacity to ameliorate the pathology in an animal model of advanced-stage muscular dystrophy suggests that interventions ultimately proven to exert a therapeutic effect in young patients may offer benefits to older patients or those with advanced conditions of progressive muscular dystrophy.
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PMID:Systemic microdystrophin gene delivery improves skeletal muscle structure and function in old dystrophic mdx mice. 1833 86

Duchenne muscular dystrophy (DMD) is a fatal, progressive, muscle-wasting disease caused by defects in the dystrophin. No viral vector except the helper-dependent adenovirus vector (HDAdv) can package 14-kilobase (kb) full-length dystrophin complementary DNA (cDNA), and HDAdv is considerably safer than old-generation adenovirus vectors because of the large-size deletion in its genome. We have generated HDAdv that carries myc-tagged murine full-length dystrophin cDNA (HDAdv-myc-mFLdys). We injected it into multiple proximal muscles of 7-day-old utrophin/dystrophin double knockout mice (dko mice) (which typically show symptoms quite similar to human DMD) because the proximal muscles are affected in DMD patients. Eight weeks after the injections, the transduced dystrophin was widely expressed, and we found a significant reduction in centrally nucleated myofibers and the restoration of the dystrophin-associated proteins, beta-dystroglycan (beta-DG) and alpha-sarcoglycan (alpha-SG), as well as neuronal nitric oxide synthase (nNOS). The injected dko mice also showed an increase in body weight, an improvement in motor performance, and a prolongation of life span. Using HDAdv, we could treat DMD model mice even by transferring the therapeutic gene into multiple skeletal muscles. Our results suggest that multiple intramuscular administrations of HDAdv carrying full-length dystrophin cDNA may reduce symptoms and compensate for lost functions in DMD patients.
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PMID:Transduction of full-length dystrophin to multiple skeletal muscles improves motor performance and life span in utrophin/dystrophin double knockout mice. 1833 87

Duchenne muscular dystrophy is a fatal muscle-wasting disorder. Lack of dystrophin compromises the integrity of the sarcolemma and results in myofibers that are highly prone to contraction-induced injury. Recombinant adeno-associated virus (rAAV)-mediated dystrophin gene transfer strategies to muscle for the treatment of Duchenne muscular dystrophy (DMD) have been limited by the small cloning capacity of rAAV vectors and high titers necessary to achieve efficient systemic gene transfer. In this study, we assess the impact of codon optimization on microdystrophin (DeltaAB/R3-R18/DeltaCT) expression and function in the mdx mouse and compare the function of two different configurations of codon-optimized microdystrophin genes (DeltaAB/R3-R18/DeltaCT and DeltaR4-R23/DeltaCT) under the control of a muscle-restrictive promoter (Spc5-12). Codon optimization of microdystrophin significantly increases levels of microdystrophin mRNA and protein after intramuscular and systemic administration of plasmid DNA or rAAV2/8. Physiological assessment demonstrates that codon optimization of DeltaAB/R3-R18/DeltaCT results in significant improvement in specific force, but does not improve resistance to eccentric contractions compared with noncodon-optimized DeltaAB/R3-R18/DeltaCT. However, codon-optimized microdystrophin DeltaR4-R23/DeltaCT completely restored specific force generation and provided substantial protection from contraction-induced injury. These results demonstrate that codon optimization of microdystrophin under the control of a muscle-specific promoter can significantly improve expression levels such that reduced titers of rAAV vectors will be required for efficient systemic administration.
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PMID:Codon and mRNA sequence optimization of microdystrophin transgenes improves expression and physiological outcome in dystrophic mdx mice following AAV2/8 gene transfer. 1876 74

Inhibition or blockade of myostatin, a negative growth factor of skeletal muscle, enhances muscle growth and therefore is considered a promising strategy for the treatment of muscle-wasting diseases such as the muscular dystrophies. Previously, we showed that myostatin blockade in both normal and dystrophin-deficient mdx mice by systemic delivery of the myostatin propeptide (MPRO) gene by an adeno-associated virus serotype 8 (AAV8) vector could enhance muscle growth and ameliorate dystrophic lesions. Here, we further investigate whether the muscle growth effect of myostatin blockade can be achieved in dogs by gene transfer. First, we cloned the canine MPRO gene, packaged it in the AAV8 vector, and showed robust muscle-enhancing effects after systemic delivery into neonatal mice. This vector was then further tested in two 3-month-old normal dogs (weighing 9.7 and 6.3 kg). The vector was delivered to one limb by hydrodynamic vein injection, and the contralateral limb served as a control. The delivery procedure was safe, without discernible adverse effects. AAV vector DNA and MPRO gene expression were detected by quantitative polymerase chain reaction, Western blotting, and immunofluorescence staining of muscle biopsies. Overexpression of MPRO resulted in enhanced muscle growth without a cytotoxic T lymphocytic immune response, as evidenced by larger myofibers in multiple muscles, increased muscle volume determined by magnetic resonance imaging, and the lack of CD4+ and CD8+ T cell infiltration in the vector-injected limbs. Our preliminary study thus supports further investigation of this therapeutic strategy in the dystrophin-deficient golden retriever muscular dystrophy dog model.
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PMID:Hydrodynamic limb vein injection of adeno-associated virus serotype 8 vector carrying canine myostatin propeptide gene into normal dogs enhances muscle growth. 1882 9

Muscular dystrophies refer to a group of inherited disorders characterized by progressive muscle weakness, wasting and degeneration. So far, there is no effective treatment but new gene-based therapies are currently being developed with particular noted advances in using conventional gene replacement strategies, RNA-based approaches, or cell-based gene therapy with a main focus on Duchenne muscular dystrophy (DMD). DMD is the most common and severe form of muscular dystrophy and current treatments are far from adequate. However, genetic and cell-based therapies, in particular exon skipping induced by antisense strategies, and corrective gene therapy via functionally engineered dystrophin genes hold great promise, with several clinical trials ongoing. Proof-of-concept of exon skipping has been obtained in animal models, and most recently in clinical trials; this approach represents a promising therapy for a subset of patients. In addition, gene-delivery-based strategies exist both for antisense-induced reading frame restoration, and for highly efficient delivery of functional dystrophin mini- and micro-genes to muscle fibres in vivo and muscle stem cells ex-vivo. In particular, AAV-based vectors show efficient systemic gene delivery to skeletal muscle directly in vivo, and lentivirus-based vectors show promise of combining ex vivo gene modification strategies with cell-mediated therapies.
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PMID:Gene therapy for muscular dystrophy: current progress and future prospects. 1952 8

The muscular dystrophies are a heterogeneous group of over 40 disorders that are characterised by muscle weakness and wasting. The most common are Duchenne muscular dystrophy and Becker muscular dystrophy, which result from mutations within the gene encoding dystrophin; myotonic dystrophy type 1, which results from an expanded trinucleotide repeat in the myotonic dystrophy protein kinase gene; and facioscapulohumeral dystrophy, which is associated with contractions in the subtelomeric region of human chromosome 1. Currently the only treatments involve clinical management of symptoms, although several promising experimental strategies are emerging. These include gene therapy using adeno-associated viral, lentiviral and adenoviral vectors and nonviral vectors, such as plasmid DNA. Exon-skipping and cell-based therapies have also shown promise in the effective treatment and regeneration of dystrophic muscle. The availability of numerous animal models for Duchenne muscular dystrophy has enabled extensive testing of a wide range of therapeutic approaches for this type of disorder. Consequently, we focus here on the therapeutic developments for Duchenne muscular dystrophy as a model of the types of approaches being considered for various types of dystrophy. We discuss the advantages and limitations of each therapeutic strategy, as well as prospects and recent successes in the context of future clinical applications.
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PMID:Emerging strategies for cell and gene therapy of the muscular dystrophies. 1955 15

Duchenne muscular dystrophy is a lethal muscle-wasting disease that affects boys. Mutations in the dystrophin gene result in the absence of the dystrophin glycoprotein complex (DGC) from muscle plasma membranes. In healthy muscle fibers, the DGC forms a link between the extracellular matrix and the cytoskeleton to protect against contraction-induced membrane lesions and to regulate cell signaling. The absence of the DGC results in aberrant regulation of inflammatory signaling cascades. Inflammation is a key pathological characteristic of dystrophic muscle lesion formation. However, the role and regulation of this process in the disease time-course has not been sufficiently examined. The transcription factor nuclear factor-kappaB has been shown to contribute to the disease process and is likely involved with increased inflammatory gene expression, including cytokines and chemokines, found in dystrophic muscle. These aberrant signaling processes may regulate the early time-course of inflammatory events that contribute to the onset of disease. This review critically evaluates the possibility that dystrophic muscle lesions in both patients with Duchenne muscular dystrophy and mdx mice are the result of immune-mediated mechanisms that are regulated by inflammatory signaling and also highlights new therapeutic directions.
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PMID:Immune-mediated mechanisms potentially regulate the disease time-course of duchenne muscular dystrophy and provide targets for therapeutic intervention. 1969 29

Sarcoglycanopathies are a group of autosomal recessive muscle-wasting disorders caused by genetic defects in one of four cell membrane glycoproteins, alpha-, beta-, gamma- or delta-sarcoglycan. These four sarcoglycans form a subcomplex that is closely linked to the major dystrophin-associated protein complex, which is essential for membrane integrity during muscle contraction and provides a scaffold for important signalling molecules. Proper assembly, trafficking and targeting of the sarcoglycan complex is of vital importance, and mutations that severely perturb tetramer formation and localisation result in sarcoglycanopathy. Gene defects in one sarcoglycan cause the absence or reduced concentration of the other subunits. Most genetic defects generate mutated proteins that are degraded through the cell's quality control system; however, in many cases, conformational modifications do not affect the function of the protein, yet it is recognised as misfolded and prematurely degraded. Recent evidence shows that misfolded sarcoglycans could be rescued to the cell membrane by assisting their maturation along the ER secretory pathway. This review summarises the etiopathogenesis of sarcoglycanopathies and highlights the quality control machinery as a potential pharmacological target for therapy of these genetic disorders.
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PMID:Sarcoglycanopathies: molecular pathogenesis and therapeutic prospects. 1978 Nov 8

Duchenne muscular dystrophy (DMD) is a severe muscle-wasting disease caused by frame shifting and nonsense mutations in the dystrophin gene. Through skipping of an (additional) exon from the pre-mRNA, the reading frame can be restored. This can be achieved with antisense oligonucleotides (AONs), which induce exon skipping by binding to splice sites or splice enhancer sites. The resulting protein will be shorter but at least partially functional. So far, exon skipping has been very successful in cell cultures, in mouse and dog models, and even in a first exploratory study in patients. Current research mainly focuses on optimization of systemic AON delivery. Here we give an overview of the available mouse models. To obtain the most informative results for future clinical application, research may have to move from the currently preferred mdx mouse to mouse models more comparable to patients, such as the utrophin/dystrophin-negative mouse and the hDMD mouse models. Further, we briefly discuss two AON backbone chemistries that are currently in clinical trials for DMD exon skipping. We propose that different chemistries should be further developed in parallel in order to hasten the transfer of the exon skipping therapy to the clinic.
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PMID:Development of antisense-mediated exon skipping as a treatment for duchenne muscular dystrophy. 1979 79


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