title: Motor performance of young dystrophic mdx mice treated with long-circulating prednisolone liposomes.
abstract: For Duchenne muscular dystrophy (DMD), a common myopathy that leads to severe disability, no causal therapy is available. Glucocorticosteroids improve patients' muscle strength, but their long-term use is limited by negative side effects. Thus, pharmacological modifications of glucocorticosteroids are required to increase the efficacy by drug targeting. Liposomal encapsulation augments systemic half-life and local tissue concentrations of glucocorticosteroids and, at the same time, reduces systemic side effects. In this study, the efficacy of novel, long-circulating, polyethylene-glycol-coated liposomes encapsulating prednisolone was compared with free prednisolone in the treatment of mdx mice, a well-established animal model for DMD. Using an objective and sensitive computerized 24-hr detection system of voluntary wheel-running in single cages, we demonstrate a significant impairment of the running performance in mdx compared with black/10 control mice aged 3-6 weeks. Treatment with liposomal or free prednisolone did not improve running performance compared with saline control or empty liposomes. Histopathological parameters, including the rate of internalized nuclei and fiber size variation, and mRNA and protein expression levels of transforming growth factor (TGF)-β and monocytes chemotactic protein (MCP)-1 also remained unchanged. Bioactivity in skeletal muscle of liposomal and free prednisolone was demonstrated by elevated mRNA expression of muscle ring finger protein 1 (MuRF1), a mediator of muscle atrophy, and its forkhead box transcription factors (Foxo1/3). Our data support the assessment of voluntary running to be a robust and reproducible outcome measure of skeletal muscle performance during the early disease course of mdx mice and suggest that liposomal encapsulation is not superior in treatment efficacy compared with conventional prednisolone. Our study helps to improve the future design of experimental treatment in animal models of neuromuscular diseases.
authors.affiliation: Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Weller
authors.forename: Jana
authors.initials: J
authors.lastname: Zschüntzsch
authors.forename: Gregor
authors.initials: G
authors.lastname: Makosch
authors.forename: Josbert M
authors.initials: JM
authors.lastname: Metselaar
authors.forename: Florian
authors.initials: F
authors.lastname: Klinker
authors.forename: Lars
authors.initials: L
authors.lastname: Klinge
authors.forename: David
authors.initials: D
authors.lastname: Liebetanz
authors.forename: Jens
authors.initials: J
authors.lastname: Schmidt
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D003402:Creatine Kinase / Q000097:blood; D004195:Disease Models, Animal; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D005938:Glucocorticoids / Q000008:administration & dosage*; D008081:Liposomes / Q000627:therapeutic use*; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D009043:Motor Activity / Q000187:drug effects*; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D053580:Muscle Strength / Q000187:drug effects / Q000235:genetics; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D020388:Muscular Dystrophy, Duchenne / Q000097:blood / Q000188:drug therapy* / Q000235:genetics / Q000503:physiopathology*; D011092:Polyethylene Glycols / Q000008:administration & dosage; D011239:Prednisolone / Q000008:administration & dosage*; D012333:RNA, Messenger / Q000378:metabolism; D000070584:Tripartite Motif Proteins; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism
chemical_list: D051858:Forkhead Transcription Factors; D005938:Glucocorticoids; D008081:Liposomes; D009124:Muscle Proteins; D012333:RNA, Messenger; D000070584:Tripartite Motif Proteins; D011092:Polyethylene Glycols; D011239:Prednisolone; C499084:Trim63 protein, mouse; D044767:Ubiquitin-Protein Ligases; D003402:Creatine Kinase