scholarly journals Low dystrophin variability between muscles and stable expression over time in Becker muscular dystrophy using capillary Western immunoassay

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Z. Koeks ◽  
A. A. Janson ◽  
C. Beekman ◽  
M. Signorelli ◽  
H. A. van Duyvenvoorde ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Longitudinal Muscle ◽  
Vastus Lateralis ◽  
Becker Muscular Dystrophy ◽  
Dystrophin Expression ◽  
Two Samples ◽  
Anterior Tibial ◽  
Total Variability ◽  
Muscle Biopsies ◽  
Over Time

AbstractBecker muscular dystrophy (BMD) is the milder allelic variant of Duchenne muscular dystrophy, with higher dystrophin levels. To anticipate on results of interventions targeting dystrophin expression it is important to know the natural variation of dystrophin expression between different muscles and over time. Dystrophin was quantified using capillary Western immunoassay (Wes) in the anterior tibial (TA) muscle of 37 BMD patients. Variability was studied using two samples from the same TA biopsy site in nine patients, assessing nine longitudinal TA biopsies, and eight simultaneously obtained vastus lateralis (VL) muscle biopsies. Measurements were performed in duplicate with two primary antibodies. Baseline dystrophin levels were correlated to longitudinal muscle strength and functional outcomes. Results showed low technical variability and high precision for both antibodies. Dystrophin TA levels ranged from 4.8 to 97.7%, remained stable over a 3–5 year period, and did not correlate with changes in longitudinal muscle function. Dystrophin levels were comparable between TA and VL muscles. Intra-muscle biopsy variability was low (5.2% and 11.4% of the total variability of the two antibodies). These observations are relevant for the design of clinical trials targeting dystrophin production, and may urge the need for other biomarkers or surrogate endpoints.

scholarly journals High-Throughput Digital Image Analysis Reveals Distinct Patterns of Dystrophin Expression in Dystrophinopathy Patients

2021 ◽  
Author(s):  
Silvia Torelli ◽  
Domenic Scaglioni ◽  
Valentina Sardone ◽  
Matthew J Ellis ◽  
Joana Domingos ◽  
...  
Keyword(s):  
Image Analysis ◽  
Muscular Dystrophy ◽  
High Throughput ◽  
Expression Patterns ◽  
Becker Muscular Dystrophy ◽  
Clear Understanding ◽  
Incurable Disease ◽  
Dystrophin Expression ◽  
Dmd Gene ◽  
Muscle Biopsies

Abstract Duchenne muscular dystrophy (DMD) is an incurable disease caused by out-of-frame DMD gene deletions while in frame deletions lead to the milder Becker muscular dystrophy (BMD). In the last decade several antisense oligonucleotides drugs have been developed to induce a partially functional internally deleted dystrophin, similar to that produced in BMD, and expected to ameliorate the disease course. The pattern of dystrophin expression and functionality in dystrophinopathy patients is variable due to multiple factors, such as molecular functionality of the dystrophin and its distribution. To benchmark the success of therapeutic intervention, a clear understanding of dystrophin expression patterns in dystrophinopathy patients is vital. Recently, several groups have used innovative techniques to quantify dystrophin in muscle biopsies of children but not in patients with milder BMD. This study reports on dystrophin expression using both Western blotting and an automated, high-throughput, image analysis platform in DMD, BMD, and intermediate DMD/BMD skeletal muscle biopsies. Our results found a significant correlation between Western blot and immunofluorescent quantification indicating consistency between the different methodologies. However, we identified significant inter- and intradisease heterogeneity of patterns of dystrophin expression in patients irrespective of the amount detected on blot, due to variability in both fluorescence intensity and dystrophin sarcolemmal circumference coverage. Our data highlight the heterogeneity of the pattern of dystrophin expression in BMD, which will assist the assessment of dystrophin restoration therapies.

scholarly journals MR biomarkers predict clinical function in Duchenne muscular dystrophy

Neurology ◽  
2020 ◽  
Vol 94 (9) ◽  
pp. e897-e909 ◽  
Author(s):  
Alison M. Barnard ◽  
Rebecca J. Willcocks ◽  
William T. Triplett ◽  
Sean C. Forbes ◽  
Michael J. Daniels ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Lower Extremity ◽  
Vastus Lateralis ◽  
Strong Relationship ◽  
Biceps Femoris ◽  
Loss Of Function ◽  
Long Head ◽  
Biceps Femoris Long Head ◽  
Over Time

ObjectiveTo investigate the potential of lower extremity magnetic resonance (MR) biomarkers to serve as endpoints in clinical trials of therapeutics for Duchenne muscular dystrophy (DMD) by characterizing the longitudinal progression of MR biomarkers over 48 months and assessing their relationship to changes in ambulatory clinical function.MethodsOne hundred sixty participants with DMD were enrolled in this longitudinal, natural history study and underwent MR data acquisition of the lower extremity muscles to determine muscle fat fraction (FF) and MRI T2 biomarkers of disease progression. In addition, 4 tests of ambulatory function were performed. Participants returned for follow-up data collection at 12, 24, 36, and 48 months.ResultsLongitudinal analysis of the MR biomarkers revealed that vastus lateralis FF, vastus lateralis MRI T2, and biceps femoris long head MRI T2 biomarkers were the fastest progressing biomarkers over time in this primarily ambulatory cohort. Biomarker values tended to demonstrate a nonlinear, sigmoidal trajectory over time. The lower extremity biomarkers predicted functional performance 12 and 24 months later, and the magnitude of change in an MR biomarker over time was related to the magnitude of change in function. Vastus lateralis FF, soleus FF, vastus lateralis MRI T2, and biceps femoris long head MRI T2 were the strongest predictors of future loss of function, including loss of ambulation.ConclusionsThis study supports the strong relationship between lower extremity MR biomarkers and measures of clinical function, as well as the ability of MR biomarkers, particularly those from proximal muscles, to predict future ambulatory function and important clinical milestones.ClinicalTrials.gov identifierNCT01484678.

scholarly journals Duchenne and Becker muscular dystrophy: a molecular and immunohistochemical approach

2007 ◽  
Vol 65 (1) ◽  
pp. 73-76 ◽  
Author(s):  
Aline Andrade Freund ◽  
Rosana Herminia Scola ◽  
Raquel Cristina Arndt ◽  
Paulo José Lorenzoni ◽  
Claudia Kamoy Kay ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Muscular Atrophy ◽  
Hot Spot ◽  
Dystrophin Gene ◽  
Becker Muscular Dystrophy ◽  
Congenital Myopathy ◽  
Specific Method ◽  
Dystrophin Deficiency ◽  
Muscle Biopsies ◽  
Female Carriers

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are caused by mutations in the dystrophin gene. We studied 106 patients with a diagnosis of probable DMD/BMD by analyzing 20 exons of the dystrophin gene in their blood and, in some of the cases, by immunohistochemical assays for dystrophin in muscle biopsies. In 71.7% of the patients, deletions were found in at least one of the exons; 68% of these deletions were in the hot-spot 3' region. Deletions were found in 81.5% of the DMD cases and in all the BMD cases. The cases without deletions, which included the only woman in the study with DMD, had dystrophin deficiency. The symptomatic female carriers had no deletions but had abnormal dystrophin distribution in the sarcolemma (discontinuous immunostains). The following diagnoses were made for the remaining cases without deletions with the aid of a muscle biopsy: spinal muscular atrophy, congenital myopathy; sarcoglycan deficiency and unclassified limb-girdle muscular dystrophy. Dystrophin analysis by immunohistochemistry continues to be the most specific method for diagnosis of DMD/BMD and should be used when no exon deletions are found in the dystrophin gene in the blood.

scholarly journals Correlation of Utrophin Levels with the Dystrophin Protein Complex and Muscle Fibre Regeneration in Duchenne and Becker Muscular Dystrophy Muscle Biopsies

PLoS ONE ◽  
2016 ◽  
Vol 11 (3) ◽  
pp. e0150818 ◽  
Author(s):  
Narinder Janghra ◽  
Jennifer E. Morgan ◽  
Caroline A. Sewry ◽  
Francis X. Wilson ◽  
Kay E. Davies ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Muscle Fibre ◽  
Protein Complex ◽  
Becker Muscular Dystrophy ◽  
Dystrophin Protein ◽  
Muscle Biopsies

scholarly journals Evidence of Insulin Resistance and Other Metabolic Alterations in Boys with Duchenne or Becker Muscular Dystrophy

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Maricela Rodríguez-Cruz ◽  
Raúl Sanchez ◽  
Rosa E. Escobar ◽  
Oriana del Rocío Cruz-Guzmán ◽  
Mardia López-Alarcón ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Muscular Dystrophy ◽  
Glucose Metabolism ◽  
Molecular Mechanisms ◽  
Becker Muscular Dystrophy ◽  
Body Fat Mass ◽  
Metabolic Alterations ◽  
Underweight Patients ◽  
Dmd Gene ◽  
Muscle Biopsies

Aim. Our aim was (1) to determine the frequency of insulin resistance (IR) in patients with Duchenne/Becker muscular dystrophy (DMD/BMD), (2) to identify deleted exons of DMD gene associated with obesity and IR, and (3) to explore some likely molecular mechanisms leading to IR.Materials and Methods. In 66 patients with DMD/BMD without corticosteroids treatment, IR, obesity, and body fat mass were evaluated. Molecules involved in glucose metabolism were analyzed in muscle biopsies. Results show that 18.3%, 22.7%, and 68% were underweight, overweight, or obese, and with high adiposity, respectively; 48.5% and 36.4% presented hyperinsulinemia and IR, respectively. Underweight patients (27.3%) exhibited hyperinsulinemia and IR. Carriers of deletions in exons 45 (OR = 9.32; 95% CI = 1.16–74.69) and 50 (OR = 8.73; 95% CI = 1.17–65.10) from DMD gene presented higher risk for IR than noncarriers. We observed a greater staining of cytoplasmic aggregates for GLUT4 in muscle biopsies than healthy muscle tissue.Conclusion. Obesity, hyperinsulinemia, and IR were observed in DMD/BMD patients and are independent of corticosteroids treatment. Carriers of deletion in exons 45 or 50 from DMD gene are at risk for developing IR. It is suggested that alteration in GLUT4 in muscle fibers from DMD patients could be involved in IR.

scholarly journals Immunohistochemical alterations of dystrophin in congenital muscular dystrophy

1995 ◽  
Vol 53 (3a) ◽  
pp. 416-423 ◽  
Author(s):  
Lineu Cesar Werneck ◽  
Eduardo Bonilla
Keyword(s):  
Plasma Membrane ◽  
Muscular Dystrophy ◽  
Muscle Biopsy ◽  
Polyclonal Antibody ◽  
Autosomal Recessive ◽  
Congenital Muscular Dystrophy ◽  
Becker Muscular Dystrophy ◽  
Muscle Membrane ◽  
Total Absence ◽  
Dystrophin Expression

The dystrophin distribution in the plasma muscle membrane using immunohystochemistry was studied in 22 children with congenital muscular dystrophy. The dystrophin was detected by immunofluorescence in muscle biopsy through a polyclonal antibody. All the cases had patchy interruptions of the fluorescence in the plasma membrane. A large patchy interruption of the sarcolemma was found in 17 cases, small interruption in 12, and a combination of large and small patchy discontinuity in 7. Small gaps around the fiber like a rosary were found in 15 cases. The frequency of these abnormalities ranged cases from: all fibers in 5 cases, frequent in 8, occasional in 5, and rare in 4. Five cases had total absence of immunofluorescence. These results suggest that the dystrophin expression is abnormal in this group of children and that this type of abnormalities can not be differentiated from early Becker muscular dystrophy nor childhood autosomal recessive muscular dystrophy through immunohystochemistry alone.

scholarly journals Pathological evaluation of rats carrying in-frame mutations in the dystrophin gene: a new model of Becker muscular dystrophy

2020 ◽  
Vol 13 (9) ◽  
pp. dmm044701
Author(s):  
Naomi Teramoto ◽  
Hidetoshi Sugihara ◽  
Keitaro Yamanouchi ◽  
Katsuyuki Nakamura ◽  
Koichi Kimura ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Gene Mutations ◽  
Dystrophin Gene ◽  
Becker Muscular Dystrophy ◽  
Severe Form ◽  
Independent Manner ◽  
Glycoprotein Complex ◽  
Dystrophin Expression ◽  
Pathological Evaluation ◽  
Dystrophin Glycoprotein Complex

ABSTRACTDystrophin, encoded by the DMD gene on the X chromosome, stabilizes the sarcolemma by linking the actin cytoskeleton with the dystrophin-glycoprotein complex (DGC). In-frame mutations in DMD cause a milder form of X-linked muscular dystrophy, called Becker muscular dystrophy (BMD), characterized by the reduced expression of truncated dystrophin. So far, no animal model with in-frame mutations in Dmd has been established. As a result, the effect of in-frame mutations on the dystrophin expression profile and disease progression of BMD remains unclear. In this study, we established a novel rat model carrying in-frame Dmd gene mutations (IF rats) and evaluated the pathology. We found that IF rats exhibited reduced expression of truncated dystrophin in a proteasome-independent manner. This abnormal dystrophin expression caused dystrophic changes in muscle tissues but did not lead to functional deficiency. We also found that the expression of additional dystrophin named dpX, which forms the DGC in the sarcolemma, was associated with the appearance of truncated dystrophin. In conclusion, the outcomes of this study contribute to the further understanding of BMD pathology and help elucidate the efficiency of dystrophin recovery treatments in Duchenne muscular dystrophy, a more severe form of X-linked muscular dystrophy.

scholarly journals Mutation-Based Therapeutic Strategies for Duchenne Muscular Dystrophy: From Genetic Diagnosis to Therapy

2019 ◽  
Vol 9 (1) ◽  
pp. 16 ◽  
Author(s):  
Akinori Nakamura
Keyword(s):  
Muscular Dystrophy ◽  
Single Gene ◽  
Genetic Diagnosis ◽  
Exon Skipping ◽  
Becker Muscular Dystrophy ◽  
Therapeutic Strategies ◽  
Severe Phenotype ◽  
Reading Frame ◽  
Dystrophin Expression ◽  
Dmd Gene

Duchenne and Becker muscular dystrophy (DMD/BMD) are X-linked muscle disorders caused by mutations of the DMD gene, which encodes the subsarcolemmal protein dystrophin. In DMD, dystrophin is not expressed due to a disruption in the reading frame of the DMD gene, resulting in a severe phenotype. Becker muscular dystrophy exhibits a milder phenotype, having mutations that maintain the reading frame and allow for the production of truncated dystrophin. To date, various therapeutic approaches for DMD have been extensively developed. However, the pathomechanism is quite complex despite it being a single gene disorder, and dystrophin is expressed not only in a large amount of skeletal muscle but also in cardiac, vascular, intestinal smooth muscle, and nervous system tissue. Thus, the most appropriate therapy would be complementation or restoration of dystrophin expression, such as gene therapy using viral vectors, readthrough therapy, or exon skipping therapy. Among them, exon skipping therapy with antisense oligonucleotides can restore the reading frame and yield the conversion of a severe phenotype to one that is mild. In this paper, I present the significance of molecular diagnosis and the development of mutation-based therapeutic strategies to complement or restore dystrophin expression.

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