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31P and 1H nuclear magnetic resonance spectroscopy characterization of skeletal muscle pH dysregulation in Duchenne muscular dystrophy patients at rest
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Abstracts 2017 / Neuromuscular Disorders 27 (2017) S96–S249
P.88 Muscle MRI protocol for progression evaluation in inclusion body myositis and Becker muscular dystrophy-baseline data L. Maggi 1, M. Pasanisi 1, F. Mazzi 1, M. Verri 1, R. Frangiamore 1, M. Moscatelli 2, L. Chiapparini 1, R. Mantegazza 1, M. Bruzzone 1, D. Aquino 1 1 Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy; 2 Università degli Studi di Milano, Milan, Italy To date, no effective treatment is available for Becker muscular dystrophy (BMD) and sporadic inclusion body myositis (sIBM). However, there is a number of promising therapeutic strategies, which are in preclinical development or have moved into clinical trials. Hence, sensitive and specific tools are required for assessment of possible benefit from new treatments. In this regards muscle MRI has been considered a possible alternative outcome measure in these myopathies, although there is no consensus on what muscle MRI protocol should be performed. The purpose of the present monocenter study is to investigate the relation between different muscle MRI sequences and clinical outcome measures in BMD and sIBM patients by direct correlation with clinical and myometric evaluation. We present here baseline findings. The subject images were acquired with a 1.5T Siemens Avanto MRI scanner. The protocol was composed by the following sequences to estimate muscular damage and fat infiltration: 1) a standard axial T1; 2) a volumetric T2-weighted sequence; 3) a 12-echoes spin-echo sequence for the relaxometry analysis; 4) a 2-point Dixon sequence for fat fraction (FF) quantification; 5) a diffusion tensor imaging sequence to study water diffusivity in the muscular tissue. Muscle MRI data were compared with age-matched and sex-matched healthy controls to test validity of our findings. We evaluated 21 patients, aged between 18 and 80 years (mean value 54.1 ± 21.5); 11 patients had sIBM and 10 BMD. Mean baseline muscle FF at thigh level was 44.8 ± 29% in sIBM patients and 39.4 ± 24% in BMD; mean baseline value at leg level was 27.4 ± 26.2% in sIBM and 30.3 ± 22% in BMD. We expect this study will provide a tool for IBM and BMD assessment in clinical practice and in future therapeutic trials. http://dx.doi.org/10.1016/j.nmd.2017.06.118
P.89 31 P and 1H nuclear magnetic resonance spectroscopy characterization of skeletal muscle pH dysregulation in Duchenne muscular dystrophy patients at rest H. Reyngoudt, S. Turk, P. Carlier Institute of Myology, Paris, France It has long been established that skeletal muscle pH of Duchenne patients is systematically measured as abnormally alkaline by 31P nuclear magnetic resonance spectroscopy (NMRS). This alkaline phosphate pool may arise from an expanded interstitial space, possibly in connection with fibrotic changes, or from the myocytic cytoplasm, reflecting ionic regulation disturbances. Both mechanisms seem to coexist. With 1H NMRS, however, intracellular pH (pHi) can be specifically measured exploiting the pH-sensitive proton resonances of carnosine. The aim here was to perform both 1H and 31P NMRS in DMD patients (n = 20) and healthy controls (n = 7). 31P and 1H NMRS data were acquired in gastrocnemius medialis muscle. A multi-spin multi-echo (MSME) sequence was used to determine water T2 and fat fraction. Whereas all DMD patients showed an elevated pH compared to healthy controls with 31P NMRS, 1 H NMRS pH was not systematically increased. Interestingly, the carnosine pHi was never found alkaline in absence of concurrent Pi pH elevation. Also, carnosine pHi was hardly ever associated with normal water T2 values. Elevated 31 P-derived pH values were observed in both the presence and absence of elevated water T2. The combined 1H and 31P approach confirmed that the prominent alkaline Pi resonance in dystrophic muscle can originate either from a cell pH dysregulation in leaky damaged myocytes or an increased volume fraction of the interstitium, impossible to distinguish using 31P NMRS alone. But more, the combined approach allowed the identification of the predominating mechanism. When pH values are in agreement, they point
toward cell dystrophic lesions. When they are discordant, this suggest the presence of a second alkaline Pi pool arising from an increased interstitial volume fraction, possibly related to fibrosis.Contrary to 31P NMRS, carnosine 1 H NMRS probes specifically the ionic regulation disturbances in dystrophic myocytes and might then possibly be used as a biomarker to assess normalization of sarcolemma permeability following induction of dystrophin production in DMD patients. http://dx.doi.org/10.1016/j.nmd.2017.06.119
P.90 Nuclear magnetic resonance relaxometry characterization of D2-mdx mice A. Martins-Bach 1, E. Araujo 1, B. Matot 1, Y. Fromes 1, P. Baudin 2, I. Richard 3, P. Carlier 1 1 Institute of Myology, Paris, France; 2 Consultants for Research in Imaging and Spectroscopy, Tournai, Belgium; 3 Généthon, Evry, France The C57BL/10-mdx mouse (mdx) is the most frequently studied animal model of Duchenne muscle dystrophy (DMD), where the absence of dystrophin in skeletal muscle leads to inflammation and necrosis in the histological analysis. Nevertheless, mdx mice have an overall benign phenotype, with high rates of muscle regeneration and moderate fibrosis. When in the DBA/2J genetic background (D2-mdx), dystrophin absence leads to a more severe phenotype, in special with increased interstitial fibrosis. The purpose of this study was to characterize D2-mdx mice by nuclear magnetic resonance (NMR) imaging, in comparison to mdx and DBA/2J wild-type mice (WT). Seven D2-mdx, 5 mdx and 5 WT male mice were evaluated at 10 weeks of age. NMR was done under isoflurane anesthesia in a 7T system and included T1 weighted images, T1 and T2 measurements. Four muscle groups were evaluated: tibialis anterior (TA), gastrocnemii (G), quadriceps (Q) and hamstrings (HM). Statistical analysis was performed on SPSS, with 1-factor ANOVA followed by post-hoc Bonferroni multiple comparison test and a correlation analysis between T1 and T2. While D2-mdx mice had similar T1 values as WT mice for all muscles, mdx mice displayed increased T1 when compared to WT mice for TA (p < 0.01), and increased T1 when compared to D2-mdx mice for TA (p < 0.05) and HM (p < 0.01). D2-mdx mice showed higher muscle water T2 in G and HM than WT mice (p < 0.01), and lower water T2 values than mdx in TA, Q and HM muscles (p < 0.01). Water T2 was increased in mdx mice in all muscles when compared to WT mice (p < 0.001). T1 and T2 values correlated for all mouse strains (p < 0.01). Despite the worse phenotype and similar degrees of inflammation and muscle degeneration, D2-mdx mice did not present as high T1 and T2 NMR values as mdx mice. These results indicate that increases in T1 and T2 due to dystrophin absence are partly compensated by additional variables in D2-mdx mice, such as muscle fibrosis. http://dx.doi.org/10.1016/j.nmd.2017.06.120
P.91 Quantitative analysis of muscle resonance imaging of fatty infiltration of the pelvic and lower limb muscles in Duchenne muscular dystrophy using excel based auto calculation program A. Hirasawa 1, A. Ishiyama 1, T. Nakayama 2, S. Kuru 3, E. Takeshita 1, Y. Shimizu-Motohashi 1, H. Komaki 1, I. Nishino 4, M. Sasaki 1 1 National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan; 2 Yokohama Rosai Hospital, Yokohama, Japan; 3 NHO Suzuka Hospital, Mie, Japan; 4 National Institute of Neuroscience, Tokyo, Japan The signal of pixels on muscle magnetic resonance imaging (MRI) was considered to be proportional to the ratio of muscle to fat; thus, we previously developed the excel based auto-calculation program of muscle impairment ratio from absolute CT value and we applied this method to MR images. The impairment ratio of the muscle was calculated from the average pixel values of each muscle. The ratio increased with increasing fat content. We used the
Abstracts 2017 / Neuromuscular Disorders 27 (2017) S96–S249
P.88 Muscle MRI protocol for progression evaluation in inclusion body myositis and Becker muscular dystrophy-baseline data L. Maggi 1, M. Pasanisi 1, F. Mazzi 1, M. Verri 1, R. Frangiamore 1, M. Moscatelli 2, L. Chiapparini 1, R. Mantegazza 1, M. Bruzzone 1, D. Aquino 1 1 Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy; 2 Università degli Studi di Milano, Milan, Italy To date, no effective treatment is available for Becker muscular dystrophy (BMD) and sporadic inclusion body myositis (sIBM). However, there is a number of promising therapeutic strategies, which are in preclinical development or have moved into clinical trials. Hence, sensitive and specific tools are required for assessment of possible benefit from new treatments. In this regards muscle MRI has been considered a possible alternative outcome measure in these myopathies, although there is no consensus on what muscle MRI protocol should be performed. The purpose of the present monocenter study is to investigate the relation between different muscle MRI sequences and clinical outcome measures in BMD and sIBM patients by direct correlation with clinical and myometric evaluation. We present here baseline findings. The subject images were acquired with a 1.5T Siemens Avanto MRI scanner. The protocol was composed by the following sequences to estimate muscular damage and fat infiltration: 1) a standard axial T1; 2) a volumetric T2-weighted sequence; 3) a 12-echoes spin-echo sequence for the relaxometry analysis; 4) a 2-point Dixon sequence for fat fraction (FF) quantification; 5) a diffusion tensor imaging sequence to study water diffusivity in the muscular tissue. Muscle MRI data were compared with age-matched and sex-matched healthy controls to test validity of our findings. We evaluated 21 patients, aged between 18 and 80 years (mean value 54.1 ± 21.5); 11 patients had sIBM and 10 BMD. Mean baseline muscle FF at thigh level was 44.8 ± 29% in sIBM patients and 39.4 ± 24% in BMD; mean baseline value at leg level was 27.4 ± 26.2% in sIBM and 30.3 ± 22% in BMD. We expect this study will provide a tool for IBM and BMD assessment in clinical practice and in future therapeutic trials. http://dx.doi.org/10.1016/j.nmd.2017.06.118
P.89 31 P and 1H nuclear magnetic resonance spectroscopy characterization of skeletal muscle pH dysregulation in Duchenne muscular dystrophy patients at rest H. Reyngoudt, S. Turk, P. Carlier Institute of Myology, Paris, France It has long been established that skeletal muscle pH of Duchenne patients is systematically measured as abnormally alkaline by 31P nuclear magnetic resonance spectroscopy (NMRS). This alkaline phosphate pool may arise from an expanded interstitial space, possibly in connection with fibrotic changes, or from the myocytic cytoplasm, reflecting ionic regulation disturbances. Both mechanisms seem to coexist. With 1H NMRS, however, intracellular pH (pHi) can be specifically measured exploiting the pH-sensitive proton resonances of carnosine. The aim here was to perform both 1H and 31P NMRS in DMD patients (n = 20) and healthy controls (n = 7). 31P and 1H NMRS data were acquired in gastrocnemius medialis muscle. A multi-spin multi-echo (MSME) sequence was used to determine water T2 and fat fraction. Whereas all DMD patients showed an elevated pH compared to healthy controls with 31P NMRS, 1 H NMRS pH was not systematically increased. Interestingly, the carnosine pHi was never found alkaline in absence of concurrent Pi pH elevation. Also, carnosine pHi was hardly ever associated with normal water T2 values. Elevated 31 P-derived pH values were observed in both the presence and absence of elevated water T2. The combined 1H and 31P approach confirmed that the prominent alkaline Pi resonance in dystrophic muscle can originate either from a cell pH dysregulation in leaky damaged myocytes or an increased volume fraction of the interstitium, impossible to distinguish using 31P NMRS alone. But more, the combined approach allowed the identification of the predominating mechanism. When pH values are in agreement, they point
toward cell dystrophic lesions. When they are discordant, this suggest the presence of a second alkaline Pi pool arising from an increased interstitial volume fraction, possibly related to fibrosis.Contrary to 31P NMRS, carnosine 1 H NMRS probes specifically the ionic regulation disturbances in dystrophic myocytes and might then possibly be used as a biomarker to assess normalization of sarcolemma permeability following induction of dystrophin production in DMD patients. http://dx.doi.org/10.1016/j.nmd.2017.06.119
P.90 Nuclear magnetic resonance relaxometry characterization of D2-mdx mice A. Martins-Bach 1, E. Araujo 1, B. Matot 1, Y. Fromes 1, P. Baudin 2, I. Richard 3, P. Carlier 1 1 Institute of Myology, Paris, France; 2 Consultants for Research in Imaging and Spectroscopy, Tournai, Belgium; 3 Généthon, Evry, France The C57BL/10-mdx mouse (mdx) is the most frequently studied animal model of Duchenne muscle dystrophy (DMD), where the absence of dystrophin in skeletal muscle leads to inflammation and necrosis in the histological analysis. Nevertheless, mdx mice have an overall benign phenotype, with high rates of muscle regeneration and moderate fibrosis. When in the DBA/2J genetic background (D2-mdx), dystrophin absence leads to a more severe phenotype, in special with increased interstitial fibrosis. The purpose of this study was to characterize D2-mdx mice by nuclear magnetic resonance (NMR) imaging, in comparison to mdx and DBA/2J wild-type mice (WT). Seven D2-mdx, 5 mdx and 5 WT male mice were evaluated at 10 weeks of age. NMR was done under isoflurane anesthesia in a 7T system and included T1 weighted images, T1 and T2 measurements. Four muscle groups were evaluated: tibialis anterior (TA), gastrocnemii (G), quadriceps (Q) and hamstrings (HM). Statistical analysis was performed on SPSS, with 1-factor ANOVA followed by post-hoc Bonferroni multiple comparison test and a correlation analysis between T1 and T2. While D2-mdx mice had similar T1 values as WT mice for all muscles, mdx mice displayed increased T1 when compared to WT mice for TA (p < 0.01), and increased T1 when compared to D2-mdx mice for TA (p < 0.05) and HM (p < 0.01). D2-mdx mice showed higher muscle water T2 in G and HM than WT mice (p < 0.01), and lower water T2 values than mdx in TA, Q and HM muscles (p < 0.01). Water T2 was increased in mdx mice in all muscles when compared to WT mice (p < 0.001). T1 and T2 values correlated for all mouse strains (p < 0.01). Despite the worse phenotype and similar degrees of inflammation and muscle degeneration, D2-mdx mice did not present as high T1 and T2 NMR values as mdx mice. These results indicate that increases in T1 and T2 due to dystrophin absence are partly compensated by additional variables in D2-mdx mice, such as muscle fibrosis. http://dx.doi.org/10.1016/j.nmd.2017.06.120
P.91 Quantitative analysis of muscle resonance imaging of fatty infiltration of the pelvic and lower limb muscles in Duchenne muscular dystrophy using excel based auto calculation program A. Hirasawa 1, A. Ishiyama 1, T. Nakayama 2, S. Kuru 3, E. Takeshita 1, Y. Shimizu-Motohashi 1, H. Komaki 1, I. Nishino 4, M. Sasaki 1 1 National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan; 2 Yokohama Rosai Hospital, Yokohama, Japan; 3 NHO Suzuka Hospital, Mie, Japan; 4 National Institute of Neuroscience, Tokyo, Japan The signal of pixels on muscle magnetic resonance imaging (MRI) was considered to be proportional to the ratio of muscle to fat; thus, we previously developed the excel based auto-calculation program of muscle impairment ratio from absolute CT value and we applied this method to MR images. The impairment ratio of the muscle was calculated from the average pixel values of each muscle. The ratio increased with increasing fat content. We used the