A Brief Review of Duchenne Muscular Dystrophy Treatment Options, with an Emphasis on Two Novel Strategies

Research progress on the application of virtual reality technology in patients with Duchenne muscular dystrophy

Duchenne muscular dystrophy is a common hereditary muscular dystrophy, virtual reality technology as an emerging therapeutic method has been gradually applied to the rehabilitation treatment of Duchenne muscular dystrophy patients. This paper reviews the current management status of Duchenne muscular dystrophy patients, the application effect of virtual reality technology in the rehabilitation treatment of Duchenne muscular dystrophy patients, and points out the challenges faced by the application of virtual reality technology in the field of Duchenne muscular dystrophy, aiming to provide a basis for the care of muscular dystrophy patients.

The SIRT1 activator SRT2104 exerts exercise mimetic effects and promotes Duchenne muscular dystrophy recovery

Duchenne muscular dystrophy (DMD) is a devastating genetic disorder, whose management is still a major challenge, despite progress in genetic and pharmacological disease-modifying treatments have been made. Mitochondrial dysfunctions contribute to DMD, however, there are no effective mitochondrial therapies for DMD. SIRT1 is a NAD+-dependent deacetylase that controls several key processes and whose impairment is involved in determining mitochondrial dysfunction in DMD. In addition to well-known resveratrol, other potent selective activators of SIRT1 exist, with better pharmacokinetics properties and a safer profile. Among these, SRT2104 is the most promising and advanced in clinical studies. Here we unveil the beneficial effects of SRT2104 in flies, mice, and patient-derived myoblasts as different models of DMD, demonstrating an anti-inflammatory, anti-fibrotic, and pro-regenerative action of the drug. We elucidate, by molecular dynamics simulations, that a conformational selection mechanism is responsible for the activation of SIRT1. Further, the impact of SRT2104 in reshaping muscle proteome and acetylome profiles has been investigated, highlighting effects that mimic those induced by exercise. Overall, our data suggest SRT2104 as a possible therapeutic candidate to successfully counteract DMD progression.

The Uneven Effect of Rare Diseases on Functional Status and Work Capacity

Background: Rare diseases are defined as clinical conditions that affect only a small number of persons in a population, considered fewer than 1 per 2000 in the European Union or fewer than 1 per 1600 in the United States They are serious, often chronic and progressive conditions, characterized by a pronounced clinical polymorphism that crosses all medical specialties. Multiple areas of life beyond just physical health are affected with significant impact on patients, families, and healthcare systems. Objective: To analyze the socio-demographic, medical, and vocational characteristics that correlate with functional status and work disability as a measure of quality of life in rare diseases. Methods: An observational retrospective study of adults with rare diseases evaluated for eligibility for social insurance rights in the National Institute of Medical Assessment and Work Capacity Rehabilitation Bucharest (INEMRCM, the Romanian abbreviation) over a 5-year period was made. Descriptive analysis was used to present sample characteristics. Means and standard deviations (SD) were calculated to describe numerical variables, frequencies were used to describe categorical variables, and logistic regression analysis was conducted to evaluate potential predictors of work capacity. All statistical analyses were performed by PSPP.3 software. p < 0.05 was the cut-off for statistical significance with a 95% confidence interval. Results: 90 consecutive persons were included in the survey. The mean age of the group was 44.5 years ± SD 10.61 years, with a female/male ratio of 48/42 persons. The mean disease duration was 10.61 years ± SD 9.76 years. Men had more severe disease (73.81%); p = 0.018 and significantly younger retirement age, M/F = 39.10 ± 12.26/43.06 ± 9.32; p = 0.037. Less disabling diseases were predominant autoimmune conditions (85.71% of cases); genetic conditions had a more severe functional impact in 63.75% of cases; p = 0.037. People with multisystem diseases but with specific or targeted treatment can work more frequently (76.19%); those with visual impairment have more severe impairments (73.77%); p < 0.001. All individuals who received specific therapy had a better functional status, unlike only 37.21% of those who received symptomatic treatment or treatment for complications; p = 0.023. Logistic regression analysis indicated that the type of impairment and the availability of specific treatments could serve as predictors of a reduced likelihood of employment in rare disease cases. Education level and occupation were not correlated with functional impairment and work disability (NS). Conclusions: Several factors, including some that are modifiable, were associated with better outcomes, such as reduced disability and an increased potential for work participation. Sex, disease etiology, type of impairment, and treatment were all significantly linked to functional capacity. Among these, the type of impairment and the availability of specific treatments might be predictors of employment. Addressing these parameters requires a multidisciplinary team, involving specialized care and comprehensive support services to improve the overall quality of life of individuals affected by rare diseases.

Safety and Tolerability of Wharton's Jelly-Derived Mesenchymal Stem Cells for Patients With Duchenne Muscular Dystrophy: A Phase 1 Clinical Study

BACKGROUND AND PURPOSE

This study was an open-label, dose-escalation, phase 1 clinical trial to determine the safety and dose of EN001 for patients with Duchenne muscular dystrophy (DMD). EN001, developed by ENCell, are allogeneic early-passage Wharton's jelly-derived mesenchymal stem cells that originate at the umbilical cord, with preclinical studies demonstrating their high therapeutic efficacy for DMD.

METHODS

This phase 1 clinical trial explored the safety and tolerability of EN001 as a potential treatment option for patients with DMD. Six pediatric participants with DMD were divided into two subgroups of equal size: low-dose EN001 (5.0×10⁵ cells/kg) and high-dose EN001 (2.5×10⁶ cells/kg). All participants were monitored for 12 weeks after EN001 administration to assess its safety. Dose-limiting toxicity (DLT) was evaluated across 2 weeks post administration. Exploratory efficacy was evaluated by measuring serum creatine kinase levels, and functional evaluations-including spirometry, myometry, the North Star Ambulatory Assessment, and the 6-minute walk test-were conducted at week 12 and compared with the baseline values.

RESULTS

No participants experienced serious adverse events related to EN001 injection during the 12-week follow-up period. Mild adverse events included injection-related local erythema, edema, parosmia, and headache, but DLT was not observed. Functional evaluations at week 12 revealed no significant changes from baseline.

CONCLUSIONS

These results demonstrated that EN001 are safe and well tolerated for patients with DMD, and did not cause serious adverse events. The efficacy of EN001 could be confirmed through larger-scale future studies that incorporate repeated dosing and have a randomized controlled trial design.

Chimeric Cell Therapy Transfers Healthy Donor Mitochondria in Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is a severe X-linked disorder characterized by dystrophin gene mutations and mitochondrial dysfunction, leading to progressive muscle weakness and premature death of DMD patients. We developed human Dystrophin Expressing Chimeric (DEC) cells, created by the fusion of myoblasts from normal donors and DMD patients, as a foundation for DT-DEC01 therapy for DMD. Our preclinical studies on mdx mouse models of DMD revealed enhanced dystrophin expression and functional improvements in cardiac, respiratory, and skeletal muscles after systemic intraosseous DEC administration. The current study explored the feasibility of mitochondrial transfer and fusion within the created DEC cells, which is crucial for developing new therapeutic strategies for DMD. Following mitochondrial staining with MitoTracker Deep Red and MitoTracker Green dyes, mitochondrial fusion and transfer was assessed by Flow cytometry (FACS) and confocal microscopy. The PEG-mediated fusion of myoblasts from normal healthy donors (MBN/MBN) and normal and DMD-affected donors (MBN/MBDMD), confirmed the feasibility of myoblast and mitochondrial fusion and transfer. The colocalization of the mitochondrial dyes MitoTracker Deep Red and MitoTracker Green confirmed the mitochondrial chimeric state and the creation of chimeric mitochondria, as well as the transfer of healthy donor mitochondria within the created DEC cells. These findings are unique and significant, introducing the potential of DT-DEC01 therapy to restore mitochondrial function in DMD patients and in other diseases where mitochondrial dysfunction plays a critical role.

The Effects of Growth Hormone Treatment Beyond Growth Promotion in Patients with Genetic Syndromes: A Systematic Review of the Literature

Recombinant human growth hormone therapy (rhGH) has been widely accepted as the safe treatment for short stature in children with such genetic syndromes as Prader-Willi syndrome and Turner or Noonan syndrome. Some patients with short stature and rare genetic syndromes are treated with rhGH as growth hormone-deficient individuals or as children born small for their gestational age. After years of experience with this therapy in syndromic short stature, it has been proved that there are some aspects of long-term rhGH treatment beyond growth promotion, which can justify rhGH use in these individuals. This paper summarizes the data of a literature review of the effects of rhGH treatment beyond growth promotion in selected genetic syndromes. We chose three of the most common syndromes, Prader-Willi, Turner, and Noonan, in which rhGH treatment is indicated, and three rarer syndromes, Silver-Russel, Kabuki, and Duchenne muscular dystrophy, in which rhGH treatment is not widely indicated. Many studies have shown a significant impact of rhGH therapy on body composition, resting energy expenditure, insulin sensitivity, muscle tonus, motor function, and mental and behavioral development. Growth promotion is undoubtedly the primary benefit of rhGH therapy; nevertheless, especially with genetic syndromes, the additional effects should also be considered as important indications for this treatment.

A review on mechanistic insights into structure and function of dystrophin protein in pathophysiology and therapeutic targeting of Duchenne muscular dystrophy

Duchenne Muscular Dystrophy (DMD) is an X-linked recessive genetic disorder characterized by progressive and severe muscle weakening and degeneration. Among the various forms of muscular dystrophy, it stands out as one of the most common and impactful, predominantly affecting boys. The condition arises due to mutations in the dystrophin gene, a key player in maintaining the structure and function of muscle fibers. The manuscript explores the structural features of dystrophin protein and their pivotal roles in DMD. We present an in-depth analysis of promising therapeutic approaches targeting dystrophin and their implications for the therapeutic management of DMD. Several therapies aiming to restore dystrophin protein or address secondary pathology have obtained regulatory approval, and many others are ongoing clinical development. Notably, recent advancements in genetic approaches have demonstrated the potential to restore partially functional dystrophin forms. The review also provides a comprehensive overview of the status of clinical trials for major therapeutic genetic approaches for DMD. In addition, we have summarized the ongoing therapeutic approaches and advanced mechanisms of action for dystrophin restoration and the challenges associated with DMD therapeutics.

Cross-species modeling of muscular dystrophy in Caenorhabditis elegans using patient-derived extracellular vesicles

Reliable disease models are critical for medicine advancement. Here, we established a versatile human disease model system using patient-derived extracellular vesicles (EVs), which transfer a pathology-inducing cargo from a patient to a recipient naïve model organism. As a proof of principle, we applied EVs from the serum of patients with muscular dystrophy to Caenorhabditis elegans and demonstrated their capability to induce a spectrum of muscle pathologies, including lifespan shortening and robust impairment of muscle organization and function. This demonstrates that patient-derived EVs can deliver disease-relevant pathologies between species and can be exploited for establishing novel and personalized models of human disease. Such models can potentially be used for disease diagnosis, prognosis, analyzing treatment responses, drug screening and identification of the disease-transmitting cargo of patient-derived EVs and their cellular targets. This system complements traditional genetic disease models and enables modeling of multifactorial diseases and of those not yet associated with specific genetic mutations.

mCherry on Top: A Positive Read-Out Cellular Platform for Screening DMD Exon Skipping Xenopeptide-PMO Conjugates

Phosphorodiamidate morpholino oligomers (PMOs) are a special type of antisense oligonucleotides (ASOs) that can be used as therapeutic modulators of pre-mRNA splicing. Application of nucleic-acid-based therapeutics generally requires suitable delivery systems to enable efficient transport to intended tissues and intracellular targets. To identify potent formulations of PMOs, we established a new in vitro-in vivo screening platform based on mdx exon 23 skipping. Here, a new in vitro positive read-out system (mCherry-DMDEx23) is presented that is sensitive toward the PMO(Ex23) sequence mediating DMD exon 23 skipping and, in this model, functional mCherry expression. After establishment of the reporter system in HeLa cells, a set of amphiphilic, ionizable xenopeptides (XPs) was screened in order to identify potent carriers for PMO delivery. The identified best-performing PMO formulation with high splice-switching activity at nanomolar concentrations in vitro was then translated to in vivo trials, where exon 23 skipping in different organs of healthy BALB/c mice was confirmed. The predesigned in vitro-in vivo workflow enables evaluation of PMO(Ex23) carriers without change of the PMO sequence and formulation composition. Furthermore, the identified PMO-XP conjugate formulation was found to induce highly potent exon skipping in vitro and redistributed PMO activity in different organs in vivo.

Safety concerns surrounding AAV and CRISPR therapies in neuromuscular treatment

Gene therapies, notably those leveraging CRISPR and adeno-associated virus vectors (AAVs), have risen to the forefront of potential treatments for neuromuscular disorders. The recent demise of a Duchenne muscular dystrophy (DMD) patient following a trial utilizing CRISPR transactivation with AAV has cast a spotlight on the potential risks associated with these approaches.1.

Assessment of Motor Unit Potentials Duration as the Biomarker of DT-DEC01 Cell Therapy Efficacy in Duchenne Muscular Dystrophy Patients up to 12 Months After Systemic-Intraosseous Administration

Duchenne muscular dystrophy (DMD) is a lethal X-linked disease caused by mutations in the dystrophin gene, leading to muscle degeneration and wasting. Electromyography (EMG) is an objective electrophysiological biomarker of muscle fiber function in muscular dystrophies. A novel, DT-DEC01 therapy, consisting of Dystrophin Expressing Chimeric (DEC) cells created by fusing allogeneic myoblasts from normal donors with autologous myoblasts from DMD-affected patients, was assessed for safety and preliminary efficacy in boys of age 6-15 years old (n = 3). Assessments included EMG testing of selected muscles of upper (deltoideus, biceps brachii) and lower (rectus femoris and gastrocnemius) extremities at the screening visit and at 3, 6, and 12 months following systemic-intraosseous administration of a single low dose of DT-DEC01 therapy (Bioethics Committee approval no. 46/2019). No immunosuppression was administered. Safety of DT-DEC01 was confirmed by the lack of therapy-related Adverse Events or Serious Adverse Events up to 22 months following DT-DEC01 administration. EMG of selected muscles of both, ambulatory and non-ambulatory patients confirmed preliminary efficacy of DT-DEC01 therapy by an increase in motor unit potentials (MUP) duration, amplitudes, and polyphasic MUPs at 12 months. This study confirmed EMG as a reliable and objective biomarker of functional assessment in DMD patients after intraosseous administration of the novel DT-DEC01 therapy.

Safety and Efficacy of DT-DEC01 Therapy in Duchenne Muscular Dystrophy Patients: A 12 - Month Follow-Up Study After Systemic Intraosseous Administration

Duchenne Muscular Dystrophy (DMD) is a progressive and fatal muscle-wasting disease with no known cure. We previously reported the preliminary safety and efficacy up to six months after the administration of DT-DEC01, a novel Dystrophin Expressing Chimeric (DEC) cell therapy created by fusion of myoblasts of DMD patient and the normal donor. In this 12-month follow-up study, we report on the safety and functional outcomes of three DMD patients after the systemic intraosseous administration of DT-DEC01. The safety of DT-DEC01 was confirmed by the absence of Adverse Events (AE) and Severe Adverse Events (SAE) up to 21 months after intraosseous DT-DEC01 administration. The lack of presence of anti-HLA antibodies and Donors Specific Antibodies (DSA) further confirmed DT-DEC01 therapy safety. Functional assessments in ambulatory patients revealed improvements in 6-Minute Walk Test (6MWT) and timed functions of North Star Ambulatory Assessment (NSAA). Additionally, improvements in PUL2.0 test and grip strength correlated with increased Motor Unit Potentials (MUP) duration recorded by Electromyography (EMG) in both ambulatory and non-ambulatory patients. DT-DEC01 systemic effect was confirmed by improved cardiac and pulmonary parameters and daily activity recordings. This follow-up study confirmed the safety and preliminary efficacy of DT-DEC01 therapy in DMD-affected patients up to 12 months after intraosseous administration. DT-DEC01 introduces a novel concept of personalized myoblast-based cellular therapy that is irrespective of the mutation type, does not require immunosuppression or the use of viral vectors, and carries no risk of off target mutations. This establishes DT-DEC01 as a promising and universally effective treatment option for all DMD patients.