Adaptive strength gains in dystrophic muscle exposed to repeated bouts of eccentric contraction

Call, Jarrod A.; Eckhoff, Michael D.; Baltgalvis, Kristen A.; Warren, Gordon L.; Lowe, Dawn A.

doi:10.1152/japplphysiol.00942.2011

Cited by 39 publications

(57 citation statements)

References 48 publications

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“…After stimulation, the foot was passively dorsiflexed 20° back to its original resting position. For the posterior crural muscles of the mdx mice, the peroneal nerve was severed and 50 eccentric contractions were performed with 10 s of rest between contractions [5]. The servomotor passively plantarflexed the foot 19° and then the sciatic nerve was stimulated while the foot was dorsiflexed 38° at a velocity of 2000 °/s.…”

Section: Methodsmentioning

confidence: 99%

Influence of Ovarian Hormones on Strength Loss in Healthy and Dystrophic Female Mice

Kosir

Mader

Greising

et al. 2015

Medicine &Amp; Science in Sports &Amp; Exercise

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Purpose The primary objective of this study was to determine if strength loss and recovery following eccentric contractions is impaired in healthy and dystrophic female mice with low levels of ovarian hormones. Methods Female C57BL/6 (wildtype) or mdx mice were randomly assigned to ovarian-intact (Sham) and ovariectomized (Ovx) groups. Anterior crural muscles were tested for susceptibility to injury from 150 or 50 eccentric contractions in wildtype and mdx mice, respectively. An additional experiment challenged mdx mice with a 2-wk treadmill running protocol followed by an eccentric contraction injury to posterior crural muscles. Functional recovery from injury was evaluated in wildtype mice by measuring isometric torque 3, 7, 14, or 21 days following injury. Results Ovarian hormone deficiency in wildtype mice did not impact susceptibility to injury as the ~50% isometric torque loss following eccentric contractions did not differ between Sham and Ovx mice (p=0.121). Similarly in mdx mice, hormone deficiency did not affect percent of pre injury isometric torque lost by anterior crural muscles following eccentric contractions (p=0.952), but the percent of pre injury torque in posterior crural muscles was lower in Ovx compared to Sham mice (p=0.014). Recovery from injury in wildtype mice was affected by hormone deficiency. Sham mice recovered pre injury isometric strength by 14 days (96 ± 2%) while Ovx mice maintained deficits at 14 and 21 days post injury (80 ± 3% and 84 ± 2%; p<0.001) Conclusion Ovarian hormone status did not impact the vulnerability of skeletal muscle to strength loss following eccentric contractions. However, ovarian hormone deficiency did impair the recovery of muscle strength in female mice.

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Section: Methodsmentioning

confidence: 99%

Influence of Ovarian Hormones on Strength Loss in Healthy and Dystrophic Female Mice

Kosir

Mader

Greising

et al. 2015

Medicine &Amp; Science in Sports &Amp; Exercise

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“…In a recent paper studying eccentric exercise in dystrophic animals, Call et al state "...the dystrophic phenotype in mdx mice is not worsened when eccentric contractions are performed on a regular basis. In fact, muscle torque and force improved after multiple bouts of eccentric contractions, showing that substantial strength gains are possible without the presence of dystrophin" (14). This is one of a cadre of animal studies proclaiming the benefits of exercise in dystrophic muscle (7,14,15).…”

Section: Discussionmentioning

confidence: 97%

“…In fact, muscle torque and force improved after multiple bouts of eccentric contractions, showing that substantial strength gains are possible without the presence of dystrophin" (14). This is one of a cadre of animal studies proclaiming the benefits of exercise in dystrophic muscle (7,14,15). However, there are far fewer human studies regarding the effects of eccentric exercise on muscular dystrophy, in particular DMD.…”

Section: Discussionmentioning

confidence: 99%

“…In an effort to compare responses to injury, high-energy forced eccentric contractions have been used to cause damage in healthy (32,40,51,94) and dystrophic (7,25,58,70,77,81) mouse muscle and it is clear that dystrophic muscle is more susceptible to damage than healthy muscle (13,19,25,77). Nonetheless, some animal studies now show that recovery of muscle contractile function after eccentric injury is enhanced in mdx mice (7,14), suggesting the RBE is possible with dystrophic muscle. Interestingly, repeated bouts of eccentric exercise in mdx Representative axial MRI of hindlimb leg muscles from a healthy (wild type) and a dystrophic (mdx) mouse, both at 9 wk of age.…”

Section: Muscular Dystrophymentioning

confidence: 99%

“…muscles not only lack a cumulative damaging effect, but instead they actually improved muscle strength (14). Thus far, the role of exercise in neuromuscular disease, especially severe forms such as DMD, is still controversial; many believe that eccentric exercise should be performed with minimal resistance or avoided altogether (2,42,52).…”

Section: Muscular Dystrophymentioning

confidence: 99%

See 2 more Smart Citations

Eccentric exercise in aging and diseased skeletal muscle: good or bad?

Lovering

Brooks

2014

Journal of Applied Physiology

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Evidence is accumulating regarding the benefits of exercise in people who are more susceptible to injury, such as the elderly, or those with a neuromuscular disease, for example Duchenne muscular dystrophy (DMD). There appears to be a consensus that exercise can be safely performed in aging and diseased muscles, but the role of eccentric exercise is not as clear. Eccentric (lengthening) contractions have risks and benefits. Eccentric contractions are commonly performed on a daily basis, and high-force voluntary eccentric contractions are often employed in strength training paradigms with excellent results; however, high-force eccentric contractions are also linked to muscle damage. This minireview examines the benefits and safety issues of using eccentric exercise in at-risk populations. A common recommendation for all individuals is difficult to achieve, and guidelines are still being established. Some form of exercise is generally recommended with aging and even with diseased muscles, but the prescription (frequency, intensity, and duration) and type (resistance vs. aerobic) of exercise requires personal attention, as there is great diversity in the functional level and comorbidities in the elderly and those with neuromuscular disease.

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CRISPR/Cas9‐mediated genome engineering: An adeno‐associated viral (AAV) vector toolbox

Senís

Fatouros

Große

et al. 2014

Biotechnology Journal

245

204

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Its remarkable ease and efficiency make the CRISPR (clustered regularly interspaced short palindromic repeats) DNA editing machinery highly attractive as a new tool for experimental gene annotation and therapeutic genome engineering in eukaryotes. Here, we report a versatile set of plasmids and vectors derived from adeno-associated virus (AAV) that allow robust and specific delivery of the two essential CRISPR components - Cas9 and chimeric g(uide)RNA - either alone or in combination. All our constructs share a modular design that enables simple and stringent guide RNA (gRNA) cloning as well as rapid exchange of promoters driving Cas9 or gRNA. Packaging into potent synthetic AAV capsids permits CRISPR delivery even into hard-to-transfect targets, as shown for human T-cells. Moreover, we demonstrate the feasibility to direct Cas9 expression to or away from hepatocytes, using a liver-specific promoter or a hepatic miRNA binding site, respectively. We also report a streamlined and economical protocol for detection of CRISPR-induced mutations in less than 3 h. Finally, we provide original evidence that AAV/CRISPR vectors can be exploited for gene engineering in vivo, as exemplified in the liver of adult mice. Our new tools and protocols should foster the broad application of CRISPR technology in eukaryotic cells and organisms, and accelerate its clinical translation into humans.

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Adaptive strength gains in dystrophic muscle exposed to repeated bouts of eccentric contraction

Abstract: Adaptive strength gains in dystrophic muscle exposed to repeated bouts of eccentric contraction.

Cited by 39 publications

References 48 publications

Influence of Ovarian Hormones on Strength Loss in Healthy and Dystrophic Female Mice

Influence of Ovarian Hormones on Strength Loss in Healthy and Dystrophic Female Mice

Eccentric exercise in aging and diseased skeletal muscle: good or bad?

CRISPR/Cas9‐mediated genome engineering: An adeno‐associated viral (AAV) vector toolbox

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