Publications by authors named "Emily R Vasiljevski"

5 Publications

  • Page 1 of 1

L-carnitine supplementation for muscle weakness and fatigue in children with neurofibromatosis type 1: A Phase 2a clinical trial.

Am J Med Genet A 2021 Jun 21. Epub 2021 Jun 21.

Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.

Reduced muscle tone, muscle weakness, and physical fatigue can impact considerably on quality of life for children with neurofibromatosis type 1 (NF1). Human muscle biopsies and mouse models of NF1 deficiency in muscle show intramyocellular lipid accumulation, and preclinical data have indicated that L-carnitine supplementation can ameliorate this phenotype. The aim of this study is to examine whether daily L-carnitine supplementation is safe and feasible, and will improve muscle strength and reduce fatigue in children with NF1. A 12-week Phase 2a trial was conducted using 1000 mg daily oral levocarnitine tartrate supplementation. Recruited children were between 8 and 12 years old with a clinical diagnosis of NF1, history of muscle weakness and fatigue, and naïve to L-carnitine. Primary outcomes were safety (self-reporting, biochemical testing) and compliance. Secondary outcomes included plasma acylcarnitine profiles, functional measures (muscle strength, long jump, handwriting speed, 6-minute-walk test [6MWT]), and parent-reported questionnaires (PedsQL™, CBCL/6-18). Six children completed the trial with no self-reported adverse events. Biochemical tests for kidney and liver function were normal, and the average compliance was 95%. Plasma acylcarnitine levels were low, but within a range not clinically linked to carnitine deficiency. For strength measures, there was a mean 53% increase in dorsiflexion strength (95% confidence interval [CI] 8.89-60.75; p = 0.02) and mean 66% increase in plantarflexion strength (95% CI 12.99-134.1; p = 0.03). In terms of muscle performance, there was a mean 10% increase in long jump distance (95% CI 2.97-16.03; p = 0.01) and 6MWT distance (95% CI 5.88-75.45; p = 0.03). Comparison with the 1000 Norms Project data showed a significant improvement in Z-score for all of these measures. Parent reports showed no negative impact on quality of life, and the perceived benefits led to the majority of individuals remaining on L-carnitine after the study. Twelve weeks of L-carnitine supplementation is safe and feasible in children with NF1, and a Phase 3 trial should confirm the efficacy of treatment.
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http://dx.doi.org/10.1002/ajmg.a.62392DOI Listing
June 2021

Evaluating modified diets and dietary supplement therapies for reducing muscle lipid accumulation and improving muscle function in neurofibromatosis type 1 (NF1).

PLoS One 2020 10;15(8):e0237097. Epub 2020 Aug 10.

Orthopaedic Research & Biotechnology Unit, The Children's Hospital at Westmead, Westmead, New South Wales, Australia.

Neurofibromatosis type 1 (NF1) is a genetic disorder that affects a range of tissue systems, however the associated muscle weakness and fatigability can have a profound impact on quality of life. Prior studies using the limb-specific Nf1 knockout mouse (Nf1Prx1-/-) revealed an accumulation of intramyocellular lipid (IMCL) that could be rescued by a diet supplemented with L-carnitine and enriched for medium-chain fatty acids (MCFAs). In this study we used the Nf1Prx1-/- mouse to model a range of dietary interventions designed to reduce IMCL accumulation, and analyze using other modalities including in situ muscle physiology and lipid mass spectrometry. Histological IMCL accumulation was significantly reduced by a range of treatments including L-carnitine and high MCFAs alone. A low-fat diet did not affect IMCL, but did provide improvements to muscle strength. Supplementation yielded rapid improvements in IMCL within 4 weeks, but were lost once treatment was discontinued. In situ muscle measurements were highly variable in Nf1Prx1-/- mice, attributable to the severe phenotype present in this model, with fusion of the hips and an overall small hind limb muscle size. Lipidome analysis enabled segregation of the normal and modified chow diets, and fatty acid data suggested increased muscle lipolysis with the intervention. Acylcarnitines were also affected, suggestive of a mitochondrial fatty acid oxidation disorder. These data support the theory that NF1 is a lipid storage disease that can be treated by dietary intervention, and encourages future human trials.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0237097PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7446925PMC
October 2020

Lipid storage myopathies: Current treatments and future directions.

Prog Lipid Res 2018 10 9;72:1-17. Epub 2018 Aug 9.

Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia.; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia. Electronic address:

Lipid storage myopathies (LSMs) are a heterogeneous group of genetic disorders that present with abnormal lipid storage in multiple body organs, typically muscle. Patients can clinically present with cardiomyopathy, skeletal muscle weakness, myalgia, and extreme fatigue. An early diagnosis is crucial, as some LSMs can be managed by simple nutraceutical supplementation. For example, high dosage l-carnitine is an effective intervention for patients with Primary Carnitine Deficiency (PCD). This review discusses the clinical features and management practices of PCD as well as Neutral Lipid Storage Disease (NLSD) and Multiple Acyl-CoA Dehydrogenase Deficiency (MADD). We provide a detailed summary of current clinical management strategies, highlighting issues of high-risk contraindicated treatments with case study examples not previously reviewed. Additionally, we outline current preclinical studies providing disease mechanistic insight. Lastly, we propose that a number of other conditions involving lipid metabolic dysfunction that are not classified as LSMs may share common features. These include Neurofibromatosis Type 1 (NF1) and autoimmune myopathies, including Polymyositis (PM), Dermatomyositis (DM), and Inclusion Body Myositis (IBM).
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http://dx.doi.org/10.1016/j.plipres.2018.08.001DOI Listing
October 2018

Developmental dosing with a MEK inhibitor (PD0325901) rescues myopathic features of the muscle-specific but not limb-specific Nf1 knockout mouse.

Mol Genet Metab 2018 04 16;123(4):518-525. Epub 2018 Feb 16.

Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia; Discipline of Paediatrics & Child Heath, Faculty of Medicine, University of Sydney, Camperdown, NSW, Australia. Electronic address:

Neurofibromatosis Type 1 (NF1) is a common autosomal dominant genetic disorder While NF1 is primarily associated with predisposition for tumor formation, muscle weakness has emerged as having a significant impact on quality of life. NF1 inactivation is linked with a canonical upregulation Ras-MEK-ERK signaling. This in this study we tested the capacity of the small molecule MEK inhibitor PD0325901 to influence the intramyocellular lipid accumulation associated with NF1 deficiency. Established murine models of tissue specific Nf1 deletion in skeletal muscle (Nf1) and limb mesenchyme (Nf1) were tested. Developmental PD0325901 dosing of dams pregnant with Nf1 progeny rescued the phenotype of day 3 pups including body weight and lipid accumulation by Oil Red O staining. In contrast, PD0325901 treatment of 4 week old Nf1 mice for 8 weeks had no impact on body weight, muscle wet weight, activity, or intramyocellular lipid. Examination of day 3 Nf1 pups showed differences between the two tissue-specific knockout strains, with lipid staining greatest in Nf1 mice, and fibrosis higher in Nf1 mice. These data show that a MEK/ERK dependent mechanism underlies NF1 muscle metabolism during development. However, crosstalk from Nf1-deficient non-muscle mesenchymal cells may impact upon muscle metabolism and fibrosis in neonatal and mature myofibers.
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http://dx.doi.org/10.1016/j.ymgme.2018.02.009DOI Listing
April 2018

Dietary intervention rescues myopathy associated with neurofibromatosis type 1.

Hum Mol Genet 2018 02;27(4):577-588

Orthopaedic Research & Biotechnology, The Children's Hospital at Westmead, Westmead, NSW, Australia.

Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder with complex symptomology. In addition to a predisposition to tumors, children with NF1 can present with reduced muscle mass, global muscle weakness, and impaired motor skills, which can have a significant impact on quality of life. Genetic mouse models have shown a lipid storage disease phenotype may underlie muscle weakness in NF1. Herein we confirm that biopsy specimens from six individuals with NF1 similarly manifest features of a lipid storage myopathy, with marked accumulation of intramyocellular lipid, fibrosis, and mononuclear cell infiltrates. Intramyocellular lipid was also correlated with reductions in neurofibromin protein expression by western analysis. An RNASeq profile of Nf1null muscle from a muscle-specific Nf1 knockout mouse (Nf1MyoD-/-) revealed alterations in genes associated with glucose regulation and cell signaling. Comparison by lipid mass spectrometry demonstrated that Nf1null muscle specimens were enriched for long chain fatty acid (LCFA) containing neutral lipids, such as cholesterol esters and triacylglycerides, suggesting fundamentally impaired LCFA metabolism. The subsequent generation of a limb-specific Nf1 knockout mouse (Nf1Prx1-/-) recapitulated all observed features of human NF1 myopathy, including lipid storage, fibrosis, and muscle weakness. Collectively, these insights led to the evaluation of a dietary intervention of reduced LCFAs, and enrichment of medium-chain fatty acids (MCFAs) with L-carnitine. Following 8-weeks of dietary treatment, Nf1Prx1-/- mice showed a 45% increase in maximal grip strength, and a 71% reduction in intramyocellular lipid staining compared with littermates fed standard chow. These data link NF1 deficiency to fundamental shifts in muscle metabolism, and provide strong proof of principal that a dietary intervention can ameliorate symptoms.
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http://dx.doi.org/10.1093/hmg/ddx423DOI Listing
February 2018
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