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Diagnostic value of the activity of mitochondrial respiratory chain complex for mitochondrial myopathies
Abstracts 2016 / Neuromuscular Disorders 26 (2016) S88–S212 diagnosed before the age of three years. Both patients were studied by MRI (wbMRI in one case and pelvis-thighs MRI in the other). Both patients showed a similar pattern of muscular fat infiltration in T1-weighted images, with fine striations, being the gluteus maximus the most evident involved muscle. No edema was present in any case in STIR sequences. The TK2 patient studied just with pelvis-thighs MRI demonstrated muscular fat infiltration progression, with diffuse fatty infiltration of all the three gluteus muscles, quadriceps (associating the rolled cake sign within the vastus lateralis), adductors, semimembranous and biceps femoris, specially in their upper region; sartorius, gracillis and semitendinous muscles were spared in the follow-up when the patient was 15 year-old. Brain MRI and MR spectroscopy were normal. This is, to our knowledge, the first report showing specific muscle MR involvement in mitochondrial myopathies. http://dx.doi.org/10.1016/j.nmd.2016.06.336
P.307 Diagnostic value of the activity of mitochondrial respiratory chain complex for mitochondrial myopathies L. Lebrato-Hernandez 1, E. Rivas-Infante 1, A. Cortes-Rodriguez 2, P. Carbonell-Corvillo 1, L. Villareal-Perez 1, C. Marquez-Infante 1, I. Rojas-Marcos 3, E. Martinez-Fernandez 4, A. Carvajal-Hernandez 5, M. Cascajo-Almenara 2, M. Martin-Casanueva 6, J. Rodriguez-Aguilera 2, C. Paradas-Lopez 1 1 Virgen del Rocio Hospital/ IBIS, Seville, Spain; 2 Pablo Olavide University, Seville, Spain; 3 Virgen Macarena Hospital, Seville, Spain; 4 Juan Ramon Jimenez Hospital, Huelva, Spain; 5 Virgen de las Nieves Hospital, Granada, Spain; 6 12 Octubre Hospital, Madrid, Spain To determine the diagnostic value of the activity of the mitochondrial respiratory chain complex (MRCC) for mitochondrial myopathies in clinical practice. We selected the patients with muscle biopsy performed in our Unit of Neuromuscular disorders between 2013 and 2015, showing decreased activity of MRCC (according to standardized criteria). We extracted DNA from muscle and performed LR-PCR and RT-qPCR to study deletions and depletion of mitochondrial DNA (mtDNA). We analyzed the results in the groups of patients with and without defined criteria of mitochondrial disease, according to the North American mitochondrial disease consortium. We recruited 50 patients, 52% women and 48% men (average age 50 and 37 years, respectively). Among the 29 patients (57%) with diagnostic criteria, 50% showed normal MRCC activity. 75% patients with normal biopsy showed reduced MRCC activity, and only 3 of them presented clinical features of mitochondrial disease. 25 out of 50 patients showed mtDNA deletion or depletion, and 8 of them showed reduced MRCC activity. Isolated reduction of MRCC activity showed a sensitivity and specificity of 39 and 43%, respectively, and a PPV and NPV of 64 and 22%, respectively. The diagnostic value of MRCC activity is very low so the diagnosis of mitochondrial disease cannot rely on this determination. Due to its low diagnostic value, isolated MRCC reduction without other diagnostic criteria is a confusing factor in clinical practice. http://dx.doi.org/10.1016/j.nmd.2016.06.337
P.308 Systemic microangiopathy in Leber’s hereditary optic neuropathy with nt 13708 and nt 3394 mutations B. Lach 1, J. Mount 2, E. Shoubridge 3, B. Kosabek-Williams 1,2, F. Lee 4, V. Silva 2 1 McMaster University, Hamilton, Ontario, Canada; 2 Ottawa University, Ottawa, Canada; 3 McGill University, Montreal, Canada; 4 Health Canada, Ottawa, Canada Leber’s hereditary optic neuropathy (LHON) is a maternally inherited mitochondrial disease (MD) characterized by bilateral blindness affecting
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predominantly young men. Some patients have systemic and neurological manifestations and may show ragged red fibers in muscles biopsies. MRI studies detect pathological changes in CNS, indicating generalized nature of disease. Abnormalities of the retinal vessels predate visual loss. To evaluate potentially systemic vascular pathology in LHOA, we carried-out morphometric assessment of muscle capillaries in affected males (7) and females (1), female carriers (3), and malignant hyperthermia suspects (5) as controls. All patients had mDNA mutations determined. LHOA patients and carriers had mDNA point mutations at the nucleotide 13708 and 3394. Increased numbers of mitochondrial (M) and M pleomorphism was detected in the striated muscle, Schwann cells and fibroblasts, and only in a few pericytes, endothelial cells and smooth muscle cells. M aberrations persisted in the tissue cultures of muscles and fibroblasts. The affected LHON individuals differed from the carriers and control patients by showing marked thickening and reduplication of the vascular basal lamina and necrosis of pericytes. All LHON patients revealed increased total area of the extracellular matrix of capillary walls, resulting in the enlarged total capillary area. The endothelial cell area was unchanged. Microangiopathy was not seen in the carriers or control biopsies. Our study demonstrated identical mDNA mutation and similar M morphological abnormalities in many cells types in LHOA patients as well as in the subclinical carriers. However, only the individuals affected by optic neuropathy showed microangiopathy in the muscle biopsies. Whether development of blindness is related to occurrence of similar changes in the optic nerve or to a combined effect of metabolic abnormalities of oxidative phosphorylation and ischemia remains to be established. http://dx.doi.org/10.1016/j.nmd.2016.06.338
DMD TREATMENT APPROACHES II P.310 Effect of deflazacort and prednisone versus placebo on pulmonary function in boys with Duchenne muscular dystrophy who have lost ambulation J. Dubow, T. Cunniff, S. Wanaski, J. Meyer Marathon Pharmaceuticals, Northbrook, USA Duchenne muscular dystrophy (DMD) is the most common type of muscular dystrophy. As the disease progresses, weakness of respiratory muscles results into restrictive pulmonary disease, pulmonary complications and increased morbidity and mortality. This was a randomized, double-blind, placebo-controlled, active comparator, Phase 3 study that evaluated the efficacy of two deflazacort doses (0.9 mg/kg/day and 1.2 mg/kg/day) compared to prednisone (0.75 mg/kg/day) and placebo for the treatment of boys with DMD. The first segment compared deflazacort and prednisone to placebo over 12 weeks. The second segment compared the two doses of deflazacort to prednisone from 12 to 52 weeks. We conducted a post-hoc subgroup analysis analyzing the effects of deflazacort and prednisone of pulmonary function (FVC, MVV) in patients who were non-ambulatory at baseline. A total of 196 participants from 9 centers were randomized to the 4 treatment groups; 45 patients were non-ambulatory at baseline. At 12 weeks, both doses of deflazacort demonstrated improvement over placebo on FVC and MVV (p = 0.065 for 0.9 mg/kg/day on FVC, p = 0.023 for % predicted FVC and p = 0.02 for 1.2 mg/kg/day on MVV) while prednisone had larger numerical declines than placebo in both measures. Over 52 weeks of treatment deflazacort at 0.9 mg/kg/day had a 0.128 L improvement in FVC, 6.9 % improvement in % predicted FVA and an 11.1 L/min improvement in MVV compared to prednisone (NS) while deflazacort at 1.2 mg/kg/day demonstrated a 13.6 L/min improvement in MVV over prednisone (p = 0.065). More patients on deflazacort showed improvement from baseline in pulmonary function compared to prednisone. This is the first prospective, randomized, blinded study to demonstrate the benefits of deflazacort and prednisone on pulmonary function in non-ambulatory boys with DMD. Although some measures
P.307 Diagnostic value of the activity of mitochondrial respiratory chain complex for mitochondrial myopathies L. Lebrato-Hernandez 1, E. Rivas-Infante 1, A. Cortes-Rodriguez 2, P. Carbonell-Corvillo 1, L. Villareal-Perez 1, C. Marquez-Infante 1, I. Rojas-Marcos 3, E. Martinez-Fernandez 4, A. Carvajal-Hernandez 5, M. Cascajo-Almenara 2, M. Martin-Casanueva 6, J. Rodriguez-Aguilera 2, C. Paradas-Lopez 1 1 Virgen del Rocio Hospital/ IBIS, Seville, Spain; 2 Pablo Olavide University, Seville, Spain; 3 Virgen Macarena Hospital, Seville, Spain; 4 Juan Ramon Jimenez Hospital, Huelva, Spain; 5 Virgen de las Nieves Hospital, Granada, Spain; 6 12 Octubre Hospital, Madrid, Spain To determine the diagnostic value of the activity of the mitochondrial respiratory chain complex (MRCC) for mitochondrial myopathies in clinical practice. We selected the patients with muscle biopsy performed in our Unit of Neuromuscular disorders between 2013 and 2015, showing decreased activity of MRCC (according to standardized criteria). We extracted DNA from muscle and performed LR-PCR and RT-qPCR to study deletions and depletion of mitochondrial DNA (mtDNA). We analyzed the results in the groups of patients with and without defined criteria of mitochondrial disease, according to the North American mitochondrial disease consortium. We recruited 50 patients, 52% women and 48% men (average age 50 and 37 years, respectively). Among the 29 patients (57%) with diagnostic criteria, 50% showed normal MRCC activity. 75% patients with normal biopsy showed reduced MRCC activity, and only 3 of them presented clinical features of mitochondrial disease. 25 out of 50 patients showed mtDNA deletion or depletion, and 8 of them showed reduced MRCC activity. Isolated reduction of MRCC activity showed a sensitivity and specificity of 39 and 43%, respectively, and a PPV and NPV of 64 and 22%, respectively. The diagnostic value of MRCC activity is very low so the diagnosis of mitochondrial disease cannot rely on this determination. Due to its low diagnostic value, isolated MRCC reduction without other diagnostic criteria is a confusing factor in clinical practice. http://dx.doi.org/10.1016/j.nmd.2016.06.337
P.308 Systemic microangiopathy in Leber’s hereditary optic neuropathy with nt 13708 and nt 3394 mutations B. Lach 1, J. Mount 2, E. Shoubridge 3, B. Kosabek-Williams 1,2, F. Lee 4, V. Silva 2 1 McMaster University, Hamilton, Ontario, Canada; 2 Ottawa University, Ottawa, Canada; 3 McGill University, Montreal, Canada; 4 Health Canada, Ottawa, Canada Leber’s hereditary optic neuropathy (LHON) is a maternally inherited mitochondrial disease (MD) characterized by bilateral blindness affecting
S179
predominantly young men. Some patients have systemic and neurological manifestations and may show ragged red fibers in muscles biopsies. MRI studies detect pathological changes in CNS, indicating generalized nature of disease. Abnormalities of the retinal vessels predate visual loss. To evaluate potentially systemic vascular pathology in LHOA, we carried-out morphometric assessment of muscle capillaries in affected males (7) and females (1), female carriers (3), and malignant hyperthermia suspects (5) as controls. All patients had mDNA mutations determined. LHOA patients and carriers had mDNA point mutations at the nucleotide 13708 and 3394. Increased numbers of mitochondrial (M) and M pleomorphism was detected in the striated muscle, Schwann cells and fibroblasts, and only in a few pericytes, endothelial cells and smooth muscle cells. M aberrations persisted in the tissue cultures of muscles and fibroblasts. The affected LHON individuals differed from the carriers and control patients by showing marked thickening and reduplication of the vascular basal lamina and necrosis of pericytes. All LHON patients revealed increased total area of the extracellular matrix of capillary walls, resulting in the enlarged total capillary area. The endothelial cell area was unchanged. Microangiopathy was not seen in the carriers or control biopsies. Our study demonstrated identical mDNA mutation and similar M morphological abnormalities in many cells types in LHOA patients as well as in the subclinical carriers. However, only the individuals affected by optic neuropathy showed microangiopathy in the muscle biopsies. Whether development of blindness is related to occurrence of similar changes in the optic nerve or to a combined effect of metabolic abnormalities of oxidative phosphorylation and ischemia remains to be established. http://dx.doi.org/10.1016/j.nmd.2016.06.338
DMD TREATMENT APPROACHES II P.310 Effect of deflazacort and prednisone versus placebo on pulmonary function in boys with Duchenne muscular dystrophy who have lost ambulation J. Dubow, T. Cunniff, S. Wanaski, J. Meyer Marathon Pharmaceuticals, Northbrook, USA Duchenne muscular dystrophy (DMD) is the most common type of muscular dystrophy. As the disease progresses, weakness of respiratory muscles results into restrictive pulmonary disease, pulmonary complications and increased morbidity and mortality. This was a randomized, double-blind, placebo-controlled, active comparator, Phase 3 study that evaluated the efficacy of two deflazacort doses (0.9 mg/kg/day and 1.2 mg/kg/day) compared to prednisone (0.75 mg/kg/day) and placebo for the treatment of boys with DMD. The first segment compared deflazacort and prednisone to placebo over 12 weeks. The second segment compared the two doses of deflazacort to prednisone from 12 to 52 weeks. We conducted a post-hoc subgroup analysis analyzing the effects of deflazacort and prednisone of pulmonary function (FVC, MVV) in patients who were non-ambulatory at baseline. A total of 196 participants from 9 centers were randomized to the 4 treatment groups; 45 patients were non-ambulatory at baseline. At 12 weeks, both doses of deflazacort demonstrated improvement over placebo on FVC and MVV (p = 0.065 for 0.9 mg/kg/day on FVC, p = 0.023 for % predicted FVC and p = 0.02 for 1.2 mg/kg/day on MVV) while prednisone had larger numerical declines than placebo in both measures. Over 52 weeks of treatment deflazacort at 0.9 mg/kg/day had a 0.128 L improvement in FVC, 6.9 % improvement in % predicted FVA and an 11.1 L/min improvement in MVV compared to prednisone (NS) while deflazacort at 1.2 mg/kg/day demonstrated a 13.6 L/min improvement in MVV over prednisone (p = 0.065). More patients on deflazacort showed improvement from baseline in pulmonary function compared to prednisone. This is the first prospective, randomized, blinded study to demonstrate the benefits of deflazacort and prednisone on pulmonary function in non-ambulatory boys with DMD. Although some measures