Long-Term Protective Effect of Human Dystrophin Expressing Chimeric (DEC) Cell Therapy on Amelioration of Function of Cardiac, Respiratory and Skeletal Muscles in Duchenne Muscular Dystrophy

Abstract

Duchenne Muscular Dystrophy (DMD) is a lethal disease caused by mutations in dystrophin encoding gene, causing progressive degeneration of cardiac, respiratory, and skeletal muscles leading to premature death due to cardiac and respiratory failure. Currently, there is no cure for DMD. Therefore, novel therapeutic approaches are needed for DMD patients.We have previously reported functional improvements which correlated with increased dystrophin expression following administration of dystrophin expressing chimeric (DEC) cells of myoblast origin to the mdx mouse models of DMD.In the current study, we confirmed dose-dependent protective effect of human DEC therapy created from myoblasts of normal and DMD-affected donors, on restoration of dystrophin expression and amelioration of cardiac, respiratory, and skeletal muscle function at 180 days after systemic-intraosseous DEC administration to mdx/scid mouse model of DMD. Functional improvements included maintenance of ejection fraction and fractional shortening levels on echocardiography, reduced enhanced pause and expiration time on plethysmography and improved grip strength and maximum stretch induced contraction of skeletal muscles. Improved function was associated with amelioration of mdx muscle pathology revealed by reduced muscle fibrosis, reduced inflammation and improved muscle morphology confirmed by reduced number of centrally nucleated fibers and normalization of muscle fiber diameters. Our findings confirm the long-term systemic effect of DEC therapy in the most severely affected by DMD organs including heart, diaphragm, and long skeletal muscles.These encouraging preclinical data introduces human DEC as a novel therapeutic modality of Advanced Therapy Medicinal Product (ATMP) with the potential to improve or halt the progression of DMD and enhance quality of life of DMD patients. Graphical Abstract Human DEC as a novel therapeutic modality with the potential to improve or halt progression of the DMD disease and enhance quality of life of DMD patients. Graphical abstract represents manufacturing process of the human DEC therapy for the future clinical applications. 1. We report the long-term efficacy of human DEC therapy resulting in increased dystrophin expression and reduced mdx muscle pathology after systemic-intraosseous administration of human Dystrophin Expressing Chimeric (DEC) Cells to the mdx/scid mouse model of DMD. 2. Systemic administration of human DEC therapy resulted in amelioration of cardiac, respiratory and skeletal muscle function as confirmed by echocardiography, plethysmography and standard muscle strength tests respectively. 3. We introduce human DEC as a novel Advanced Therapy Medicinal Product (ATMP) for future clinical application in DMD patients.

Long-Term Biodistribution and Safety of Human Dystrophin Expressing Chimeric Cell Therapy After Systemic-Intraosseous Administration to Duchenne Muscular Dystrophy Model

“…Therefore, considering recent reports on the increased drug toxicity observed in gene therapies, as well as to address the current limitations of the allogeneic myoblast-based therapies, the primary goal of the current study was to evaluate the long-term safety of DEC cells at 180 days after systemic-intraosseous administration, in preparation for clinical application of DEC therapy in DMD patients. Furthermore, we have previously reported DEC efficacy, confirming a significant increase in dystrophin expression which correlated with improvement of function in the cardiac, respiratory and skeletal muscles (Siemionow et al 2018a , 2018b , 2019 , 2021a , 2022 ).…”

“…We have further tested effect of DEC in the immunocompetent mdx mice model and confirmed significant increase in dystrophin expression which correlated with improvement of muscle function after both, the local-intramuscular and the systemic-intraosseous administration of DEC cells created from two unrelated donors, where there was no evidence of adverse side effects and no need for immunosuppression (Siemionow et al 2018a , 2019 ). In addition, we have also confirmed in the mdx and mdx/scid mouse models of DMD, that systemic-intraosseous DEC administration resulted in the long-term amelioration of the cardiac, pulmonary and skeletal muscle function which correlated with increased dystrophin expression, improved muscle morphology and reduced mdx pathology (Siemionow et al 2019 , 2021a , 2022 ).…”

“…We previously reported restoration of dystrophin expression after systemic-intraosseous administration of human DEC cells to the mdx/scid mice (Siemionow et al 2018b , 2021a , 2022 ). In the current study, human origin of dystrophin after DEC therapy administration was confirmed by co-localization of dystrophin with the human spectrin in the selected target organs of heart (Fig.…”

“…Nuclei counterstained with DAPI (blue); Magnification of upper panel 20X, scale bar 20 μm, Magnification of the lower panel 140X, Negative controls are presented on right, upper corner with magnification 20X (ZEISS 710 META, Oberkochen, Germany). Figure adapted from the author’s publication at the Stem Cell Rev Rep journal (Siemionow et al 2022 ) …”

“…We have planned our studies and have chosen the DEC dose based on the recommendations of the World Health Organization ( 2013 ) for cell therapies dosing in the experimental models. We have also tested different doses of human DEC therapy based on the conversion of the dose from mice to humans (Elmeliegy et al 2021 ; Nair and Jacob 2016 ) and different routes of DEC cell delivery including intramuscular, intraosseous and intravenous routes (Siemionow et al 2018a , 2018b , 2019 , 2021a , 2021b , 2022 , unpublished data). Since the intraosseous route of DEC administration was found to be most efficacious for cell engraftment corresponding with increased dystrophin expression and improvement of function, we have further assessed systemic effects of DEC on cardiac, respiratory and skeletal muscles in both the immunocompetent mdx and immunocompromised mdx/scid mouse models (Siemionow et al 2019 , 2021a , 2022 ).…”