A Longitudinal Study of Quantitative Muscle Strength and Functional Motor Ability in Ambulatory Boys with Duchenne Muscular Dystrophy

2021 ◽  
pp. 1-14
Author(s):  
Cathleen E. Buckon ◽  
Susan E. Sienko ◽  
Eileen G. Fowler ◽  
Anita M. Bagley ◽  
Loretta A. Staudt ◽  
...  
Keyword(s):  
Longitudinal Study ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Strength ◽  
Genetic Disorder ◽  
Knee Extensor ◽  
Standard Of Care ◽  
Rate Of Change ◽  
Isokinetic Dynamometry ◽  
Gross Motor

Background: Duchenne muscular dystrophy (DMD) is an X-linked recessive genetic disorder, that is characterized by progressive muscle degeneration and loss of ambulation between 7–13 years of age. Novel pharmacological agents targeting the genetic defects and disease mechanisms are becoming available; however, corticosteroid (CS) therapy remains the standard of care. Objective: The purpose of this longitudinal study was to elucidate the effect of CS therapy on the rate of muscle strength and gross motor skill decline in boys with DMD and assess the sensitivity of selected outcome measures. Methods: Eighty-four ambulatory boys with DMD (49–180 months), 70 on CS, 14 corticosteroid naïve (NCS), participated in this 8-year multi-site study. Outcomes included; isokinetic dynamometry, the Standing (STD) and Walking/Running/jumping (WRJ) dimensions of the Gross Motor Function Measure (GMFM), and Timed Function Tests (TFTs). Nonlinear mixed modeling procedures determined the rate of change with age and the influence of steroids. Results: Despite CS therapy the rate of decline in strength with age was significant in all muscle groups assessed. CS therapy significantly slowed decline in knee extensor strength, as the NCS group declined at 3x the rate of the CS group. Concurrently, WRJ skills declined in the NCS group at twice the rate of the CS group. 4-stair climb and 10 meter walk/run performance was superior in the boys on CS therapy. Conclusion: CS therapy slowed the rate of muscle strength decline and afforded longer retention of select gross motor skills in boys on CS compared to boys who were NCS. Isokinetic dynamometry, Walk/Run/Jump skills, and select TFTs may prove informative in assessing the efficacy of new therapeutics in ambulatory boys with DMD.

scholarly journals Disruption of a key ligand-H-bond network drives dissociative properties in vamorolone for Duchenne muscular dystrophy treatment

2020 ◽  
Vol 117 (39) ◽  
pp. 24285-24293
Author(s):  
Xu Liu ◽  
Yashuo Wang ◽  
Jennifer S. Gutierrez ◽  
Jesse M. Damsker ◽  
Kanneboyina Nagaraju ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Side Effects ◽  
Muscular Dystrophy ◽  
Genetic Disorder ◽  
Premature Death ◽  
Standard Of Care ◽  
Therapeutic Index ◽  
Therapeutic Effects ◽  
Current Standard ◽  
Future Design

Duchenne muscular dystrophy is a genetic disorder that shows chronic and progressive damage to skeletal and cardiac muscle leading to premature death. Antiinflammatory corticosteroids targeting the glucocorticoid receptor (GR) are the current standard of care but drive adverse side effects such as deleterious bone loss. Through subtle modification to a steroidal backbone, a recently developed drug, vamorolone, appears to preserve beneficial efficacy but with significantly reduced side effects. We use combined structural, biophysical, and biochemical approaches to show that loss of a receptor-ligand hydrogen bond drives these remarkable therapeutic effects. Moreover, vamorolone uniformly weakens coactivator associations but not corepressor associations, implicating partial agonism as the main driver of its dissociative properties. Additionally, we identify a critical and evolutionarily conserved intramolecular network connecting the ligand to the coregulator binding surface. Interruption of this allosteric network by vamorolone selectively reduces GR-driven transactivation while leaving transrepression intact. Our results establish a mechanistic understanding of how vamorolone reduces side effects, guiding the future design of partial agonists as selective GR modulators with an improved therapeutic index.

Neck flexor muscle strength and its relation with functional performance in Duchenne muscular dystrophy

2017 ◽  
Vol 21 (3) ◽  
pp. 494-499
Author(s):  
Sibel Bozgeyik ◽  
İpek Alemdaroğlu ◽  
Numan Bulut ◽  
Öznur Yılmaz ◽  
Ayşe Karaduman
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Strength ◽  
Functional Performance ◽  
Flexor Muscle

scholarly journals Laminin-111 protein therapy enhances muscle regeneration and repair in the GRMD dog model of Duchenne muscular dystrophy

2019 ◽  
Vol 28 (16) ◽  
pp. 2686-2695 ◽  
Author(s):  
Pamela Barraza-Flores ◽  
Tatiana M Fontelonga ◽  
Ryan D Wuebbles ◽  
Hailey J Hermann ◽  
Andreia M Nunes ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Strength ◽  
Premature Death ◽  
Muscle Disease ◽  
Muscle Pathology ◽  
Mdx Mouse ◽  
Protein Therapy ◽  
Muscle Fibrosis ◽  
Dog Model

Abstract Duchenne muscular dystrophy (DMD) is a devastating X-linked disease affecting ~1 in 5000 males. DMD patients exhibit progressive muscle degeneration and weakness, leading to loss of ambulation and premature death from cardiopulmonary failure. We previously reported that mouse Laminin-111 (msLam-111) protein could reduce muscle pathology and improve muscle function in the mdx mouse model for DMD. In this study, we examined the ability of msLam-111 to prevent muscle disease progression in the golden retriever muscular dystrophy (GRMD) dog model of DMD. The msLam-111 protein was injected into the cranial tibial muscle compartment of GRMD dogs and muscle strength and pathology were assessed. The results showed that msLam-111 treatment increased muscle fiber regeneration and repair with improved muscle strength and reduced muscle fibrosis in the GRMD model. Together, these findings support the idea that Laminin-111 could serve as a novel protein therapy for the treatment of DMD.

scholarly journals In vivo non-invasive monitoring of dystrophin correction in a new Duchenne muscular dystrophy reporter mouse

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Leonela Amoasii ◽  
Hui Li ◽  
Yu Zhang ◽  
Yi-Li Min ◽  
Efrain Sanchez-Ortiz ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Genetic Disorder ◽  
Dystrophin Gene ◽  
Luciferase Reporter ◽  
Luciferase Expression ◽  
Gene Correction ◽  
Reading Frame ◽  
Non Invasive

Abstract Duchenne muscular dystrophy (DMD) is a fatal genetic disorder caused by mutations in the dystrophin gene. To enable the non-invasive analysis of DMD gene correction strategies in vivo, we introduced a luciferase reporter in-frame with the C-terminus of the dystrophin gene in mice. Expression of this reporter mimics endogenous dystrophin expression and DMD mutations that disrupt the dystrophin open reading frame extinguish luciferase expression. We evaluated the correction of the dystrophin reading frame coupled to luciferase in mice lacking exon 50, a common mutational hotspot, after delivery of CRISPR/Cas9 gene editing machinery with adeno-associated virus. Bioluminescence monitoring revealed efficient and rapid restoration of dystrophin protein expression in affected skeletal muscles and the heart. Our results provide a sensitive non-invasive means of monitoring dystrophin correction in mouse models of DMD and offer a platform for testing different strategies for amelioration of DMD pathogenesis.

scholarly journals Early Neurodevelopmental Findings Predict School Age Cognitive Abilities in Duchenne Muscular Dystrophy: A Longitudinal Study

PLoS ONE ◽  
2015 ◽  
Vol 10 (8) ◽  
pp. e0133214 ◽  
Author(s):  
Daniela Chieffo ◽  
Claudia Brogna ◽  
Angela Berardinelli ◽  
Grazia D’Angelo ◽  
Maria Mallardi ◽  
...  
Keyword(s):  
Longitudinal Study ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Cognitive Abilities ◽  
School Age
Sign in / Sign up

Export Citation Format

Share Document