P.13.7 Elevated muscle metabolites in Becker muscular dystrophy detected by MR spectroscopy

• Published in: Neuromuscular disorders : NMD 2013-10, Vol.23 (9), p.811-811
• Main Authors: Hooijmans, M.T, Wokke, B.H.A, van den Bergen, J.C, Aartsma-Rus, A.A, Niks, E.H, Webb, A.G, Verschuuren, J.J.G, Kan, H.E
• Format: Article
• Language: English
• Subjects: Neurology
• ISSN: 0960-8966; 1873-2364
• DOI: 10.1016/j.nmd.2013.06.601

Becker muscular dystrophy (BMD) is characterized by progressive muscle weakness and a variable disease course. Different muscles become infiltrated with fat at different rates and with varying times of onset, for which the underlying pathophysiology is unknown. Phosphorus (31 P) magnetic resonance spectroscopy has shown alterations in muscle metabolism in BMD patients. It is unknown whether muscles that do not show fatty infiltration and are therefore early in the dystrophic process already show metabolic changes. Moreover, these changes have never been studied in individual muscles. Using a 7T MRI scanner we examined the level of phosphorus muscle metabolites and the level of fatty infiltration in five main lower leg muscles.31 P 2D multivoxel data sets and a 3-point DIXON, to quantify the percentage of fat infiltration, were acquired in 24 BMD patients (20–63 years) and seven age-matched healthy controls (22–65 years). Phosphodiester (PDE) levels, which are related to cell proliferation, were significantly increased ( p < 0.05) in all lower leg muscles except the medial gastrocnemius in BMD patients compared to healthy controls. Next, all muscles were classified according to fatty infiltration, in low (0–10%) and high (>10%) fat levels. Significant increases (p < 0.05) in PDE-levels were found in the muscles of BMD patients classified in the low fat group in comparison to the healthy controls for all lower leg muscles except the medial gastrocnemius. In conclusion, PDE-levels were increased in muscles showing low levels of fatty infiltration which could point to an increased activity of membrane proliferation and repair processes prior to the occurrence of fatty infiltration. Since such processes are more likely to be reversible than fatty infiltration, PDE-levels may be a valuable biomarker to evaluate disease progression and the effect of therapeutic interventions. Current studies aim to correlate MR spectroscopy data to clinical disease parameters.