Functional protection of dystrophic mouse (mdx) muscles after adenovirus-mediated transfer of a dystrophin minigene.

Abstract

Fast skeletal muscles of mdx (X chromosome-linked muscular dystrophy) mice were injected after birth with a recombinant adenovirus containing a minidystrophin gene, a 6.3-kbp cDNA coding for the N-and Cterminal ends ofdystrophin. Adult muscles were challenged by forced lengthening during tetanic contractions. Stretchinduced mechanical and histological damages were much reduced in injected muscles, in (n = 7) or with the Ad-RSVI3gal (n = 7). When mice were 4 months old muscles were isolated under general anesthesia, which preserved circulation. The lateral part of the muscle was dissected out. The order of dissection of the Ad-RSVmDys limb vs. the other one was alternated from animal to animal.Isolated muscles were submitted to repetitive stimulations (125 Hz) for 300 msec, at 5-min intervals. During the first 160 msec, tension was developed isometrically and then a forced lengthening (1 mm; i.e., +7%, at 11.1 mm/sec) was imposed.After relaxation the muscle was returned to the resting length.Histology. At the end of the experiments, the muscles were soaked for 3 h in an oxygenated Krebs

Electrotransfer of naked DNA in the skeletal muscles of animal models of muscular dystrophies

“…Other groups have shown that the conversion of an important proportion of muscle fibers from dystrophin-negative to -positive was a prerequisite for a physiological functional benefit in the mdx model (30 to 40%). 27 The transduction efficacy presented in this study is close to these values, at least regarding the expression of ␤-gal, and would therefore be compatible with the development of a functional benefit.…”

“…However, the original nature of dystrophic muscles makes difficult the evaluation of potential additional damage raised by the electrotransfer procedure in dystrophic animals. For example, the mdx skeletal muscle is known to be especially sensitive to eccentric contractions, 27,52,53 and one may not exclude that the electrotransfer protocol may be more detrimental in certain muscular pathologies than in others.…”

“…Indeed, the transfer of a dystrophin minigene into the gastrocnemius muscle of young mdx was reported to protect partially the transduced fibers against detrimental consequences of eccentric exercise. 27 The occidental form of CMD is an autosomal disease due to the defect of the gene coding for the ␣2 chain of laminin. 11 The association of the large ␣2 chain with ␤1 and ␥1 chains constitutes the laminin-2 protein, which is an extracellular protein providing a bridge between the sarcolemmal membrane and the extracellular matrix in muscle fibers.…”

Adenovirus-mediated dystrophin minigene transfer improves muscle strength in adult dystrophic (MDX) mice

“…12 To date, AdV-mediated dystrophin gene transfer has generally been performed in immunologically immature (neonatal) mdx animals during the period that precedes the onset of major myofiber necrosis and reduced forcegenerating capacity. [25][26][27] Under these conditions, the immune response against AdV-infected cells is significantly less pronounced than in adult animals, and the longevity of dystrophin gene expression can thus be sufficient to reduce histological evidence of disease progression several weeks later 26 despite the absence of immunosuppressive therapy. However, in human patients suffering from DMD, the diagnosis is usually made at a much later stage due to the development of symptomatic muscle weakness.…”

Efficient repetitive gene delivery to skeletal muscle using recombinant adenovirus vector containing the Coxsackievirus and adenovirus receptor cDNA

“…1 Skeletal muscle is an excellent target for rAd-mediated gene therapy, [2][3][4] and rAd has delivered therapeutic genes efficiently to neonatal muscle. 5 However, the rAd-mediated gene transfer to skeletal muscle has been criticized for two problems: the limited expression of the transgene and the poor tropism of adenovirus for mature skeletal muscle fibers.…”