| 1. |
- Ávila-Polo, R., et al.
(författare)
-
Loss of Sarcomeric Scaffolding as a Common Baseline Histopathologic Lesion in Titin-Related Myopathies
- 2018
-
Ingår i: Journal of Neuropathology and Experimental Neurology. - : Oxford University Press (OUP). - 1554-6578 .- 0022-3069. ; 77:12, s. 1101-1114
-
Tidskriftsartikel (refereegranskat)abstract
- Titin-related myopathies are heterogeneous clinical conditions associated with mutations in TTN. To define their histopathologic boundaries and try to overcome the difficulty in assessing the pathogenic role of TTN variants, we performed a thorough morphological skeletal muscle analysis including light and electron microscopy in 23 patients with different clinical phenotypes presenting pathogenic autosomal dominant or autosomal recessive (AR) mutations located in different TTN domains. We identified a consistent pattern characterized by diverse defects in oxidative staining with prominent nuclear internalization in congenital phenotypes (AR-CM) (n=10), ±necrotic/regenerative fibers, associated with endomysial fibrosis and rimmed vacuoles (RVs) in AR early-onset Emery-Dreifuss-like (AR-ED) (n=4) and AR adult-onset distal myopathies (n=4), and cytoplasmic bodies (CBs) as predominant finding in hereditary myopathy with early respiratory failure (HMERF) patients (n=5). Ultrastructurally, the most significant abnormalities, particularly in AR-CM, were multiple narrow core lesions and/or clear small areas of disorganizations affecting one or a few sarcomeres with M-band and sometimes A-band disruption and loss of thick filaments. CBs were noted in some AR-CM and associated with RVs in HMERF and some AR-ED cases. As a whole, we described recognizable histopathological patterns and structural alterations that could point toward considering the pathogenicity of TTN mutations.
|
|
| 2. |
- Laforet, P., et al.
(författare)
-
Deep morphological analysis of muscle biopsies from type III glycogenesis (GSDIII), debranching enzyme deficiency, revealed stereotyped vacuolar myopathy and autophagy impairment
- 2019
-
Ingår i: Acta Neuropathologica Communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- Glycogen storage disorder type III (GSDIII), or debranching enzyme (GDE) deficiency, is a rare metabolic disorder characterized by variable liver, cardiac, and skeletal muscle involvement. GSDIII manifests with liver symptoms in infancy and muscle involvement during early adulthood. Muscle biopsy is mainly performed in patients diagnosed in adulthood, as routine diagnosis relies on blood or liver GDE analysis, followed by AGL gene sequencing. The GSDIII mouse model recapitulate the clinical phenotype in humans, and a nearly full rescue of muscle function was observed in mice treated with the dual AAV vector expressing the GDE transgene. In order to characterize GSDIII muscle morphological spectrum and identify novel disease markers and pathways, we performed a large international multicentric morphological study on 30 muscle biopsies from GSDIII patients. Autophagy flux studies were performed in human muscle biopsies and muscles from GSDIII mice. The human muscle biopsies revealed a typical and constant vacuolar myopathy, characterized by multiple and variably sized vacuoles filled with PAS-positive material. Using electron microscopy, we confirmed the presence of large nonmembrane bound sarcoplasmic deposits of normally structured glycogen as well as smaller rounded sac structures lined by a continuous double membrane containing only glycogen, corresponding to autophagosomes. A consistent SQSTM1/p62 decrease and beclin-1 increase in human muscle biopsies suggested an enhanced autophagy. Consistent with this, an increase in the lipidated form of LC3, LC3II was found in patients compared to controls. A decrease in SQSTM1/p62 was also found in the GSDIII mouse model. In conclusion, we characterized the morphological phenotype in GSDIII muscle and demonstrated dysfunctional autophagy in GSDIII human samples. These findings suggest that autophagic modulation combined with gene therapy might be considered as a novel treatment for GSDIII.
|
|
| 3. |
- Milham, Michael P., et al.
(författare)
-
An Open Resource for Non-human Primate Imaging
- 2018
-
Ingår i: Neuron. - : Elsevier BV. - 0896-6273 .- 1097-4199. ; 100:1, s. 61-74
-
Tidskriftsartikel (refereegranskat)abstract
- Non-human primate neuroimaging is a rapidly growing area of research that promises to transform and scale translational and cross-species comparative neuroscience. Unfortunately, the technological and methodological advances of the past two decades have outpaced the accrual of data, which is particularly challenging given the relatively few centers that have the necessary facilities and capabilities. The PRIMatE Data Exchange (PRIME-DE) addresses this challenge by aggregating independently acquired non-human primate magnetic resonance imaging (MRI) datasets and openly sharing them via the International Neuroimaging Data-sharing Initiative (INDI). Here, we present the rationale, design, and procedures for the PRIME-DE consortium, as well as the initial release, consisting of 25 independent data collections aggregated across 22 sites (total = 217 non-human primates). We also outline the unique pitfalls and challenges that should be considered in the analysis of non-human primate MRI datasets, including providing automated quality assessment of the contributed datasets.
|
|
| 4. |
- Bevilacqua, Jorge A, et al.
(författare)
-
"Necklace" fibers, a new histological marker of late-onset MTM1-related centronuclear myopathy.
- 2009
-
Ingår i: Acta neuropathologica. - : Springer Science and Business Media LLC. - 1432-0533 .- 0001-6322. ; 117:3, s. 283-91
-
Tidskriftsartikel (refereegranskat)abstract
- Mutations in the gene encoding the phosphoinositide phosphatase myotubularin 1 protein (MTM1) are usually associated with severe neonatal X-linked myotubular myopathy (XLMTM). However, mutations in MTM1 have also been recognized as the underlying cause of "atypical" forms of XLMTM in newborn boys, female infants, female manifesting carriers and adult men. We reviewed systematically the biopsies of a cohort of patients with an unclassified form of centronuclear myopathy (CNM) and identified four patients presenting a peculiar histological alteration in some muscle fibers that resembled a necklace ("necklace fibers"). We analyzed further the clinical and morphological features and performed a screening of the genes involved in CNM. Muscle biopsies in all four patients demonstrated 4-20% of fibers with internalized nuclei aligned in a basophilic ring (necklace) at 3 microm beneath the sarcolemma. Ultrastructurally, such necklaces consisted of myofibrils of smaller diameter, in oblique orientation, surrounded by mitochondria, sarcoplasmic reticulum and glycogen granules. In the four patients (three women and one man), myopathy developed in early childhood but was slowly progressive. All had mutations in the MTM1 gene. Two mutations have previously been reported (p.E404K and p.R241Q), while two are novel; a c.205_206delinsAACT frameshift change in exon 4 and a c.1234A>G mutation in exon 11 leading to an abnormal splicing and the deletion of nine amino acids in the catalytic domain of MTM1. Necklace fibers were seen neither in DNM2- or BIN1-related CNM nor in males with classical XLMTM. The presence of necklace fibers is useful as a marker to direct genetic analysis to MTM1 in CNM.
|
|
| 5. |
- Ohlsson, M., et al.
(författare)
-
New morphologic and genetic findings in cap disease associated with beta-tropomyosin (TPM2) mutations
- 2008
-
Ingår i: Neurology. - : American Academy of Neurology. - 0028-3878 .- 1526-632X. ; 71:23, s. 1896-1901
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Mutations in the beta-tropomyosin gene (TPM2) are a rare cause of congenital myopathies with features of nemaline myopathy and cap disease and may also cause distal arthrogryposis syndromes without major muscle pathology. We describe the muscle biopsy findings in three patients with cap disease and novel heterozygous mutations in TPM2.METHODS: Three unrelated patients with congenital myopathy were investigated by muscle biopsy and genetic analysis.RESULTS: All three patients had early-onset muscle weakness of variable severity and distribution. Muscle biopsy demonstrated in all three patients near uniformity of type 1 fibers and an unusual irregular and coarse-meshed intermyofibrillar network. By electron microscopy, the myofibrils were broad and partly split, and the Z lines appeared jagged. In one of the patients caps structures were identified only by electron microscopy, and in one patient they were identified only in a second biopsy at adulthood. Three novel, de novo, heterozygous mutations in TPM2 were identified: a three-base pair deletion in-frame (p.Lys49del), a three-base pair duplication in-frame (p.Gly52dup), and a missense mutation (p.Asn202Lys).CONCLUSIONS: Mutations in TPM2 seem to be a frequent cause of cap disease. Because cap structures may be sparse, other prominent features, such as a coarse-meshed intermyofibrillar network and jagged Z lines, may be clues to correct diagnosis and also indicate that the pathogenesis involves defective assembly of myofilaments.
|
|
