Progressive Dystrophy Research Articles

Morphological characteristics of paravertebral muscles in patients with scoliosis caused by primaryprogressive muscular dystrophies

To identify the morphological features of paraspinal muscles in patients with spinal pathology caused by progressive muscular dystrophy. The Traumatologic-and-Orthopedic Department of Axial Skeleton Pathology examined patients with scoliotic spinal deformity due to muscular dystrophy: 1) severe Duchenne X-linked muscular dystrophy (n=7); 2) Erb-Roth's autosomal recessive muscular dystrophy (n=2); 3) Landouzy-Dejerine facioscapulohumeral muscular dystrophy (n=2). For histopathological analysis of paraspinal muscles, an excisional biopsy was performed in the region of the apex of the strain angle (the convex side), and the specimens were fixed with 10% neutral formalin. Paraffin sections were stained with hematoxylin and eosin according to the Van Gieson and Masson trichrome staining methods. The preparations were examined using an AxioScope.A1 stereo microscope and an AxioCam digital camera ('Carl Zeiss MicroImaging GmbH', Germany). Sluggish moderate paraparesis and grade IV progressive neurogenic thoracolumbar scoliosis were predominant in the clinical picture of the disease. The muscle biopsy specimens were established to have muscle fiber profiles with lost polygonality, increased diameter variability, and centrally positioned or numerous internal nuclei (myophagy) and to be characterized by fiber contractures, fatty degeneration fields, interstitial fibrosis, and signs of axonopathy of intramuscular nerve conductors. The arterial blood vessels were spastic with fibrotic t. media and t. adventicia; the venous bed vessels were dilated, thin-walled, full-blooded, which causes blood corpuscle transudation and numerous hemorrhages. The identified morphopathological characteristics of muscle tissue in patients with progressive muscular dystrophy are very similar. However, Duchenne muscular dystrophy is the most severe pathology, in which fatty degeneration and sclerotization of muscle tissue and perimysial vessels are most pronounced. To solve this problem, there is a need for the integration of geneticists, biochemists, molecular biologists, pharmacologists, and histologists.

Loss of CRB2 in Müller glial cells modifies a CRB1-associated retinitis pigmentosa phenotype into a Leber congenital amaurosis phenotype.

Variations in the human Crumbs homolog-1 (CRB1) gene lead to an array of retinal dystrophies including early onset of retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA) in children. To investigate the physiological roles of CRB1 and CRB2 in retinal Müller glial cells (MGCs), we analysed mouse retinas lacking both proteins in MGC. The peripheral retina showed a faster progression of dystrophy than the central retina. The central retina showed retinal folds, disruptions at the outer limiting membrane, protrusion of photoreceptor nuclei into the inner and outer segment layers and ingression of photoreceptor nuclei into the photoreceptor synaptic layer. The peripheral retina showed a complete loss of the photoreceptor synapse layer, intermingling of photoreceptor nuclei within the inner nuclear layer and ectopic photoreceptor cells in the ganglion cell layer. Electroretinography showed severe attenuation of the scotopic a-wave at 1 month of age with responses below detection levels at 3 months of age. The double knockout mouse retinas mimicked a phenotype equivalent to a clinical LCA phenotype due to loss of CRB1. Localization of CRB1 and CRB2 in non-human primate (NHP) retinas was analyzed at the ultrastructural level. We found that NHP CRB1 and CRB2 proteins localized to the subapical region adjacent to adherens junctions at the outer limiting membrane in MGC and photoreceptors. Our data suggest that loss of CRB2 in MGC aggravates the CRB1-associated RP-like phenotype towards an LCA-like phenotype.

DUCHENNE MUSCULAR DYSTROPHY – CLINICAL: P.18The importance of nutrition in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a severe progressive muscular dystrophy caused by mutations in the DMD gene, leading to the absence of a functional dystrophin protein. Besides muscle problems, metabolic, gastrointestinal (GI), and resulting nutritional issues contribute to the pathology. This aspect of the disease is often neglected. Assessment by a dietician should be part of routine check-ups. In early stages, overweight, caused in part by corticosteroid use, is common and, together with the primary deficit in dystrophin, affects muscle and whole body metabolism. In later stages patients are at risk of undernutrition, e.g. due to problems with swallowing and chewing. When the disease progresses, GI issues, including constipation, metabolic acidosis, gastroparesis, and reflux, are often seen. The precise role of nutrition and metabolic problems has not been well-studied. There is a need for natural history data, including dietary data, and good outcome measures regarding body composition, tailored to DMD patients. Furthermore, few well-designed studies, both preclinical and clinical, into the use of dietary supplements and on nutrient requirements have been performed. Good guidelines for maintaining a healthy weight and nutritional intake are currently lacking. Additionally, the risk/benefit ratio of high doses of over-the-counter supplements, their effect on different muscle types and potential interactions with other medicines require more detailed investigation. Families should be encouraged to speak with the clinical team and the pharmacist. The importance of fluid intake and dental hygiene should be stressed as well. Guidelines for diet and supplements need to take into account the stage of the disease and background culture, and be readily accessible in understandable formats, such as short videos and one-page explanations. It may also be helpful to provide examples of recipes and alternatives to make implementation of dietary change in daily life easier.

Human Adipose-Derived CD146+ Stem Cells Increase Life Span of a Muscular Dystrophy Mouse Model More Efficiently than Mesenchymal Stromal Cells.

Duchenne muscular dystrophy is the most common and severe form of progressive muscular dystrophy. Previous results showed an increased survival in double knockout mice (dko) when treated with adipose-derived CD146+ cells. In this study, we analyzed the effect of CD146+ cells compared to mesenchymal stem/stromal cells (MSCs) derived from the same human adipose sample when injected in the dko mouse model without immunosuppression. Both CD146+ cells and MSCs increased the survival of treated mice when compared to vehicle-injected mice, with a more prominent effect of CD146+ cells than MSCs. Both CD146+ cells and MSCs suppressed peripheral blood mononuclear cell proliferation, indicating immunomodulatory properties. Co-culture experiments showed that MSCs have a more inflammatory profile expression, and angiogenesis assay showed that CD146+ cells can improve blood vessel formation. CD146+ cells can extend survival of muscular dystrophy mice more efficiently than MSCs, possibly due to immunomodulatory and angiogenic properties. Further investigations focusing on exogenous CD146+ cell role in vivo will improve cell therapy understanding and effectiveness.

Systemic Delivery of Dysferlin Overlap Vectors Provides Long-Term Gene Expression and Functional Improvement for Dysferlinopathy.

Dysferlinopathies comprise a family of disorders caused by mutations in the dysferlin (DYSF) gene, leading to a progressive dystrophy characterized by chronic muscle fiber loss, fat replacement, and fibrosis. To correct the underlying histopathology and function, expression of full-length DYSF is required. Dual adeno-associated virus vectors have been developed, defined by a region of homology, to serve as a substrate for reconstitution of the full 6.5 kb dysferlin cDNA. Previous work studied the efficacy of this treatment through intramuscular and regional delivery routes. To maximize clinical efficacy, dysferlin-deficient mice were treated systemically to target all muscles through the vasculature for efficacy and safety studies. Mice were evaluated at multiple time points between 4 and 13 months post treatment for dysferlin expression and functional improvement using magnetic resonance imaging and magnetic resonance spectroscopy and membrane repair. A systemic dose of 6 × 1012 vector genomes resulted in widespread gene expression in the muscles. Treated muscles showed a significant decrease in central nucleation, collagen deposition, and improvement of membrane repair to wild-type levels. Treated gluteus muscles were significantly improved compared to placebo-treated muscles and were equivalent to wild type in volume, intra- and extramyocellular lipid accumulation, and fat percentage using magnetic resonance imaging and magnetic resonance spectroscopy. Dual-vector treatment allows for production of full-length functional dysferlin with no toxicity. This confirms previous safety data and validates translation of systemic gene delivery for dysferlinopathy patients.

Proteomic identification of elevated saliva kallikrein levels in the mdx-4cv mouse model of Duchenne muscular dystrophy

Dystrophinopathies are multi-system disorders that affect the skeletal musculature, the cardio-respiratory system and the central nervous system. The systematic screening of suitable biofluids for released or altered proteins promises new insights into the highly complex pathophysiology of X-linked muscular dystrophy. However, standard detection approaches using antibody-based assays often fail to reproducibly detect low-abundance protein isoforms in dilute biological fluids. In contrast, mass spectrometric screening approaches enable the proteome-wide identification of minor protein changes in biofluids. This report describes the findings from the comparative proteomic analysis of whole saliva samples from wild type versus the established mdx-4cv mouse model of highly progressive muscular dystrophy, focusing on the kallikrein protein family. Kallikrein-1 (Klk1) and 13 Klk1-related peptidases were identified in saliva and serum from normal mice. Comparative proteomics revealed elevated saliva levels of the Klk1-related peptidases Klk1-b1, Klk1-b5 and Klk-b22, as well as an increased Klk-1 concentration, which agrees with higher Klk-1 levels in serum from mdx-4cv mice. This indicates altered cellular signaling, extracellular matrix remodeling and an altered immune response in the mdx-4cv mouse, and establishes liquid biopsy procedures as suitable bioanalytical tools for the systematic survey of complex pathobiochemical changes in animal models of muscular dystrophy.

The p.S85C-mutation in MATR3 impairs stress granule formation in Matrin-3 myopathy

Matrin-3-related distal myopathy is characterized mainly by progressive distal weakness of the lower extremities. The mutation p.S85C in matrin-3 (MATR3) has been identified as disease-causing alteration, whereas the specific molecular mechanisms leading to the muscle disease have not been elucidated. In the present study, muscle biopsy samples from six patients and fibroblasts from four patients harboring p.S85C mutation in MATR3 were analyzed. No specific changes in matrin-3 localization or expression were observed. In contrast, localization of the stress granule components G3BP1 and TIA1 was altered and enhanced protein- as well as RNA- expression of G3BP1 and TIA1 was observed in highly dystrophic tissues. Histological changes were pronounced in muscle biopsy specimen taken from distal muscles. In patient-derived primary fibroblasts, cellular response to oxidative stress was monitored using sodium arsenite treatment. The fraction of cells showing stress granule formation upon application of oxidative stress was significantly lower in patients' fibroblasts compared to healthy controls. Similar results were obtained for endoplasmatic reticulum stress using thapsigargin. Stress granule number in stress granule-positive cells with p.S85C mutation was significantly reduced, whereas stress granule size was not markedly altered. Consistently, cell viability upon arsenite treatment appeared significantly reduced in Matrin-3 myopathy derived fibroblasts. In summary, p.S85C mutation in matrin-3 affects the response to cellular stress by impairing stress granule formation and dynamics. This might contribute to cellular damage and progression of dystrophy in muscle of Matrin-3 myopathy.

Effects of Ovariectomy in an hSOD1-G93A Transgenic Mouse Model of Amyotrophic Lateral Sclerosis (ALS).

BackgroundAmyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterized by progressive muscular dystrophy and paralysis; most ALS patients die from respiratory failure within 3 to 5 years, and there is currently no effective treatment. Some studies have indicated sex differences in the incidence of ALS, and evidence suggests a neuroprotective role for estrogen.Material/MethodsWe used human Cu/Zn superoxide dismutase (hSOD1-G93A) transgenic mice to determine the effects of ovariotomy on the onset of disease and behavior; we also used Western blotting to measure the expression of aromatase and estrogen receptors, as well as the inflammatory cytokines and apoptosis markers, in the lumbar spinal cord to determine the mechanism of estrogen-mediated neuroprotection.ResultsOvariectomy advanced the onset of disease, down-regulated aromatase and estrogen receptor alpha (ER-α) expression, and inhibited expression of the anti-inflammatory factors arginase-1 and the anti-apoptotic factor B-cell lymphoma-2 (Bcl-2) in the lumbar spinal cord of hSOD1-G93A transgenic mice.ConclusionsOvariectomy resulted in earlier disease onset and attenuated the anti-inflammatory and anti-apoptotic actions of estrogen in hSOD1-G93A transgenic mice. Therefore, estrogen may play an important role in protecting spinal cord motor neurons.

Descriptive Characteristics of Males with Duchenne Muscular Dystrophy in Those Covered by Government (Medicaid) and Non-government (Private) Health Plans

Duchenne muscular dystrophy (DMD) is a rare, inherited neuromuscular disorder.Methods:To describe the clinical characteristics and healthcare resource utilization (HCRU) of male patients with DMD in commercial and Medicaid cohorts, this retrospective study identified male patients in the Truven Health MarketScan® Commercial and Medicaid databases diagnosed with hereditary progressive muscular dystrophy (HPMD) presumed to have DMD between 2011–2014. Patients with ≥2 medical claims with a diagnosis for HPMD (International Classification of Diseases, 9th revision, ClinicalModification:359.1) were included. Patients were followed for 12 months after diagnosis date, during which clinical characteristics and HCRU were assessed.Results:In total, 2,285 patients met the selection criteria. In these patients, corticosteroid and anti-infective agents were commonly utilized. Physician office visits were extremely common, with over 70% of all patients having at least one visit. Wheelchairs were commonly used, with the incidence of use increasing with age. Mechanical ventilators and airway clearance devices were underrepresented in the data.Conclusion:Patients with DMD had higher annual HCRU costs when compared with a non-DMD age-matched cohort, with patients in commercial cohorts having a higher annual average cost than those in Medicaid cohorts.

Pharmacological inhibition of REV-ERB stimulates differentiation, inhibits turnover and reduces fibrosis in dystrophic muscle

Duchenne muscular dystrophy (DMD) is a debilitating X-linked disorder that is fatal. DMD patients lack the expression of the structural protein dystrophin caused by mutations within the DMD gene. The absence of functional dystrophin protein results in excessive damage from normal muscle use due to the compromised structural integrity of the dystrophin associated glycoprotein complex. As a result, DMD patients exhibit ongoing cycles of muscle destruction and regeneration that promote inflammation, fibrosis, mitochondrial dysfunction, satellite cell (SC) exhaustion and loss of skeletal and cardiac muscle function. The nuclear receptor REV-ERB suppresses myoblast differentiation and recently we have demonstrated that the REV-ERB antagonist, SR8278, stimulates muscle regeneration after acute injury. Therefore, we decided to explore whether the REV-ERB antagonist SR8278 could slow the progression of muscular dystrophy. In mdx mice SR8278 increased lean mass and muscle function, and decreased muscle fibrosis and muscle protein degradation. Interestingly, we also found that SR8278 increased the SC pool through stimulation of Notch and Wnt signaling. These results suggest that REV-ERB is a potent target for the treatment of DMD.

Neuromuscular diseases: Diagnosis and management.

Neuromuscular diseases (NMDs) affect the peripheral nervous system, which includes the motor neurons and sensory neurons; the muscle itself; or the neuromuscular junction. Thus, the term NMDs encompasses a vast array of different syndromes. Some of these syndromes are of direct relevance to paediatric orthopaedic surgeons, either because the presenting manifestation is a functional sign (e.g., toe-walking) or deformity (e.g., pes cavus or scoliosis) suggesting a need for orthopaedic attention or because orthopaedic abnormalities requiring treatment develop during the course of a known NMD. The main NMDs relevant to the orthopaedic surgeon are infantile spinal muscular atrophy (a motor neuron disease), peripheral neuropathies (chiefly, Charcot-Marie-Tooth disease), congenital muscular dystrophies, progressive muscular dystrophies, and Steinert myotonic dystrophy (or myotonic dystrophy type1). Muscle weakness is a symptom shared by all these conditions. The paediatric orthopaedic surgeon must be familiar, not only with the musculoskeletal system, but also with many other domains (particularly respiratory and cardiac function and nutrition) that may interfere with the treatment and require preoperative management. Good knowledge of the natural history of each NMD is essential to ensure optimal timing of the therapeutic interventions, which must be performed under the best possible conditions in these usually frail patients. Timing is particularly crucial for the treatment of spinal deformities due to paraspinal muscle hypotonia during growth: depending on the disease and natural history, the treatment may involve non-operative methods or growing rods, followed by spinal fusion. A multidisciplinary approach is always required. Finally, the survival gains achieved in recent years increasingly require attention to preparing for adult life, to orthopaedic problems requiring treatment before the patient leaves the paediatric environment, and to the transition towards the adult healthcare system.

Treatment with the anti-IL-6 receptor antibody attenuates muscular dystrophy via promoting skeletal muscle regeneration in dystrophin-/utrophin-deficient mice

BackgroundChronic increases in the levels of the inflammatory cytokine interleukin-6 (IL-6) in serum and skeletal muscle are thought to contribute to the progression of muscular dystrophy. Dystrophin/utrophin double-knockout (dKO) mice develop a more severe and progressive muscular dystrophy than the mdx mice, the most common murine model of Duchenne muscular dystrophy (DMD). In particular, dKO mice have smaller body sizes and muscle diameters, and develop progressive kyphosis and fibrosis in skeletal and cardiac muscles. As mdx mice and DMD patients, we found that IL-6 levels in the skeletal muscle were significantly increased in dKO mice. Thus, in this study, we aimed to analyze the effects of IL-6 receptor (IL-6R) blockade on the muscle pathology of dKO mice.MethodsMale dKO mice were administered an initial injection (200 mg/kg intraperitoneally (i.p.)) of either the anti-IL-6R antibody MR16-1 or an isotype-matched control rat IgG at the age of 14 days, and were then given weekly injections (25 mg/kg i.p.) until 90 days of age.ResultsTreatment of dKO mice with the MR16-1 antibody successfully inhibited the IL-6 pathway in the skeletal muscle and resulted in a significant reduction in the expression levels of phosphorylated signal transducer and activator of transcription 3 in the skeletal muscle. Pathologically, a significant increase in the area of embryonic myosin heavy chain-positive myofibers and muscle diameter, and reduced fibrosis in the quadriceps muscle were observed. These results demonstrated the therapeutic effects of IL-6R blockade on promoting muscle regeneration. Consistently, serum creatine kinase levels were decreased. Despite these improvements observed in the limb muscles, degeneration of the diaphragm and cardiac muscles was not ameliorated by the treatment of mice with the MR16-1 antibody.ConclusionAs no adverse effects of treatment with the MR16-1 antibody were observed, our results indicate that the anti-IL-6R antibody is a potential therapy for muscular dystrophy particularly for promoting skeletal muscle regeneration.

A De novo Mutation in Dystrophin Causing Muscular Dystrophy in a Female Patient.

Background:Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) are X-linked recessive neuromuscular diseases resulting from dystrophin (DMD) gene mutations. It has been known that the carrier of DMD mutations may also have symptoms of the disease. While de novo mutation is quite common in BMD/DMD patients, it is rarely reported in the female carriers.Methods:Two sporadic Chinese patients with progressive muscular dystrophy and their familial members were recruited. The targeted next-generation sequencing (NGS) and the multiplex ligation-dependent probe analysis (MLPA) were performed in the proband. Blood tests, electrocardiography, echocardiography, and electromyography were also evaluated.Results:Two novel mutations of DMD gene were identified, c.7318C>T (p.Q2440*) in the male proband and c.4983dupA (p.A1662Sfs*24) in the female carrier. The MLPA analysis did not detect any large rearrangements. The haplotype analysis indicated that the two mutations were derived from de novo mutagenesis.Conclusions:We identified two novel de novo mutations of DMD gene in two Chinese pedigrees, one of which caused a female patient with muscular dystrophy. The mutational analysis is important for DMD patients and carriers in the absence of a family history. The NGS can help detect the mutations in MLPA-negative patients.

P.48 - Novel compound heterozygous mutations in PLEC gene causing epidermolysis bullosa simplex with muscular dystrophy, case series of two affected sisters

Epidermolysis bullosa simplex with muscular dystrophy (EBSMD) is a rare clinical entity characterized by childhood onset of progressive muscular dystrophy and blistering skin changes. It is caused by homozygous or compound heterozygous mutations in the plectin gene (PLEC). Genetic defects have been reported in a limited number of patients. The precise phenotype-genotype correlations have yet to be defined. Here we describe two affected sisters with detailed clinical presentation, exam findings including timed motor function tests, MRI images and results, and confirmed novel PLEC compound heterozygous mutations. CASE SERIES: #1 Five-year-old female born premature at 25 weeks was evaluated for motor delay. Epidermolysis bullosa (EB) was diagnosed at age 5 months with recurrent skin blisters. She sat alone at 18 months, walked at 2 years of age and never could jump with both feet. Physical exam revealed small stature and dysmorphic findings including micrognathia, high-arched palate, poor dentition with erosions, hand and foot blisters and nail deformation. Neurological examination showed generalized muscle weakness, decreased reflexes and delayed time-with-sit-to-stand, 30-feet-run, and 4-steps-climbing. CPK was elevated at 519 unit/L. Muscle MRI showed asymmetric atrophy of the quadriceps muscles, mild fatty infiltration in the quadriceps and gluteus maximus muscles and subtle increased T2 signal in the quadriceps muscles bilaterally. Genetic testing confirmed heterozygous mutations in PLEC (c.11912delA and c.6276dupA) causing frame shift stacking leading to premature stop codons. #2 Three-year-old sister was also diagnosed with EB was found to have same heterozygous PLEC mutations. She had delayed motor development and elevated CPK level. Muscle MRI was unremarkable. We presented clinical evidence that the novel compound heterozygous PLEC mutations are pathogenic for EBSMD.

Active transforming growth factor-β2 in the aqueous humor of posterior polymorphous corneal dystrophy patients.

PurposePosterior polymorphous corneal dystrophy (PPCD) is characterized by abnormal proliferation of corneal endothelial cells. It was shown that TGF-β2 present in aqueous humor (AH) could help maintaining the corneal endothelium in a G1-phase-arrest state. We wanted to determine whether the levels of this protein are changed in AH of PPCD patients.MethodsWe determined the concentrations of active TGF-β2 in the AH of 29 PPCD patients (42 samples) and 40 cadaver controls (44 samples) by ELISA. For data analysis the PPCD patients were divided based on either the molecular genetic cause of their disease as PPCD1 (37 samples), PPCD3 (1 sample) and PPCDx (not linked to a known PPCD loci, 4 samples) or on the presence (17 samples) or absence (25 samples) of secondary glaucoma or on whether they had undergone penetrating keratoplasty (PK, 32 samples) or repeated PK (rePK, 7 samples).ResultsThe level of active TGF-β2 in the AH of all PPCD patients (mean ± SD; 386.98 ± 114.88 pg/ml) in comparison to the control group (260.95 ± 112.43 pg/ml) was significantly higher (P = 0.0001). Compared to the control group, a significantly higher level of active TGF-β2 was found in the PPCD1 (P = 0.0005) and PPCDx (P = 0.0022) groups. Among patients the levels of active TGF-β2 were not significantly affected by gender, age, secondary glaucoma or by the progression of dystrophy when one or repeated PK were performed.ConclusionThe levels of active TGF-β2 in the AH of PPCD patients are significantly higher than control values, and thus the increased levels of TGF-β2 could be a consequence of the PPCD phenotype and can be considered as another feature characterizing this disease.

Proteomic profiling of the dystrophin complex and membrane fraction from dystrophic mdx muscle reveals decreases in the cytolinker desmoglein and increases in the extracellular matrix stabilizers biglycan and fibronectin.

The almost complete loss of the membrane cytoskeletal protein dystrophin and concomitant drastic reduction in dystrophin-associated glycoproteins are the underlying mechanisms of the highly progressive neuromuscular disorder Duchenne muscular dystrophy. In order to identify new potential binding partners of dystrophin or proteins in close proximity to the sarcolemmal dystrophin complex, proteomic profiling of the isolated dystrophin-glycoprotein complex was carried out. Subcellular membrane fractionation and detergent solubilisation, in combination with ion exchange, lectin chromatography and density gradient ultracentrifugation, was performed to isolate a dystrophin complex-enriched fraction. Following gradient gel electrophoresis and on-membrane digestion, the protein constituents of the dystrophin fraction were determined by peptide mass spectrometry. This proteomic strategy resulted in the novel identification of desmoglein and desmoplakin, which act as cytolinker proteins and possibly exist in close proximity to the dystrophin complex in the sarcolemma membrane. Interestingly, comparative immunoblotting showed a significant reduction in desmoglein in dystrophin-deficient mdx skeletal muscles, reminiscent of the pathobiochemical fate of the dystrophin-associated core proteins in muscular dystrophy. Comparative membrane proteomics was used to correlate this novel finding to large-scale changes in the dystrophic phenotype. A drastic increase in the extracellular stabilizers biglycan and fibronectin was shown by both mass spectrometric analysis and immunoblotting. The reduced expression of desmoglein in dystrophin-deficient skeletal muscles, and simultaneous increase in components of the extracellular matrix, suggest that muscular dystrophy is associated with plasmalemmal disintegration, loss of cellular linkage and reactive myofibrosis.

Functional Insights on the Human Adenine Nucleotide Translocator Interactome

The adenine nucleotide translocator (ANT), by mediating the exchange of ADP for ATP across the inner mitochondrial membrane, lies at the core of oxidative phosphorylation (OXPHOS). Discrepancies in ANT expression and/or activity resulting to reduced energy metabolism are linked to a wide spectrum of pathologies, including lactic acidosis, progressive external opthalmoplegia, muscular dystrophy and cardiomyopathy. In yeast, the major isoform was modeled for a long time to exist in isolation, but was demonstrated to physically interact with respiratory supercomplexes (RSCs) exclusively in the context of the phospholipid cardiolipin (CL). OXPHOS in CL‐null yeast is remarkably decreased in optimal situations and completely eliminated under stressful conditions, pointing to the physiological significance of these protein‐protein associations. In this study, we determined that human ANTs also have the capacity to assemble into high molecular weight complexes. Additionally, we defined the interactome of two human ANT isoforms using an unbiased proteomics approach. Similar to the yeast orthologue, we saw RSCs and other solute carriers as binding partners, which was surprising given that the organization of yeast and mammalian ANTs is different, with Complex I missing in yeast. To probe the physiological relevance of the ANT‐RSC interaction, we deleted the major ANT isoform in HEK293, which unexpectedly only had a moderate effect on OXPHOS, indicating that the minimal levels of the other isoforms can still support respiratory capacity. As a reciprocal inquiry, we ablated OXPHOS function and found that ADP/ATP transport by ANTs is impaired. These results provide insights regarding the physiological relevance of evolutionarily conserved interactions of proteins important for mitochondrial function.Support or Funding InformationThis work was supported by the National Institutes of Health (R01HL108882) to S.M.C and pre‐doctoral fellowships from the American Heart Association (16PRE31140006 to M.G.A. and 12PRE11910004 to Y‐W.L.).

Spinal correction in patients with Fukuyama congenital muscular dystrophy.

Fukuyama congenital muscular dystrophy (FCMD) is one of the most common congenital progressive muscular dystrophies in Japan. Some patients develop a severe spinal deformity that leads to an unstable sitting position or pain. Since 2008, we have treated FCMD using posterior spinal fusion. This study reports the short-term clinical and radiographic results of posterior spinal correction and fusion in FCMD. We retrospectively reviewed 11 consecutive FCMD patients, average age 13 years old, treated with posterior spinal instrumentation and fusion between 2008 and 2015. All patients were non-ambulatory and complained about difficulty sitting and/or buttock pain. Posterior spinal correction was performed to halt progression of spinal deformity and improve their sitting balance. Assessment was performed clinically and with radiological measurements at a mean follow up period of 34.5 months. To evaluate functional status of patients after surgery objectively, a Muscular Dystrophy Spine Questionnaire (MDSQ) was obtained at the final follow up. The mean height, weight and body mass index of the patients were 144.1±11.8cm, 26.5±8.7kg and 12.5±2.6kg/m2. The average intensive care unit stay was 1.3 days. Five patients had complications related to surgery. The mean preoperative major Cobb angle and pelvic obliquity (PO) were 65.5±41.7° and 31.4±28.9°, respectively, were corrected to 34.4±29.7° and 20.0±18.7° just after the surgery, and were maintained at 35.1±29.9° and 20.5±21.1° at the final follow up. The average MDSQ score was 35.8±13.2 at the final follow up. Posterior spinal correction and fusion in FCMD achieved good radiographic results and clinical improvement with acceptable perioperative complications. FCMD patients are mentally impaired and physically small, so post-operative observation and close attention to perioperative complications are critical.

Systemic AAV-Mediated β-Sarcoglycan Delivery Targeting Cardiac and Skeletal Muscle Ameliorates Histological and Functional Deficits in LGMD2E Mice

Limb-girdle muscular dystrophy type 2E (LGMD2E), resulting from mutations in β-sarcoglycan (SGCB), is a progressive dystrophy with deteriorating muscle function, respiratory failure, and cardiomyopathy in 50% or more of LGMD2E patients. SGCB knockout mice share many of the phenotypicdeficiencies of LGMD2E patients. To investigate systemic SGCB gene transfer to treat skeletal and cardiac muscledeficits, we designed a self-complementary AAVrh74 vector containing a codon-optimized human SGCB transgenedriven by a muscle-specific promoter. We delivered scAAV.MHCK7.hSGCB through the tail vein of SGCB-/- mice to provide a rationale for a clinical trial that would lead to clinically meaningful results. This led to 98.1% transgene expression across all muscles that was accompanied by improvements in histopathology. Serum creatine kinase (CK) levels were reduced following treatment by 85.5%. Diaphragm force production increased by 94.4%, kyphoscoliosis of the spine was significantly reduced by 48.1%, overall ambulation increased by 57%, and vertical rearing increased dramatically by 132% following treatment. Importantly, no adverse effects were seen in muscle of wild-type mice injected systemically with scAAV.hSGCB. In this well-defined model of LGMD2E, we have demonstrated the efficacy and safety of systemic scAAV.hSGCB delivery, and these findings have established a path for clinically beneficial AAV-mediated gene therapy for LGMD2E.

Smoking and Eye Pathologies. A Systemic Review. Part I. Anterior Eye Segment Pathologies.

Tobacco smoking has detrimental influence on human health and is one of the leading causes of preventable mortality worldwide, associated with lung cancer, chronic obstructive lung disease and cardiovascular disease. The analysis of the influence of tobacco smoking on pathology of the anterior segment of the eye in adults and children. A comprehensive review of the literature performed through MEDLINE and PubMed searches, was published during the period 2000-2016. In adults, tobacco smoking is associated with hyperopia, delayed corneal epithelial healing and progression of Fuchs' endothelial corneal dystrophy. Smoking is a strong risk factor for age-related nuclear cataract. However, smoking is not associated with pterygium, and its influence on dry eye symptoms, central corneal thickness and progression of primary open glaucoma remains controversial. Smoking during pregnancy increases risk of convergent or divergent strabismus or poor stereo acuity, however, its influence on anophtalmia, microphtalmia, amblyopia and hyperopic refractive error is controversial. Tobacco smoking plays an important role in the pathogenesis of many diseases of anterior eye segment leading to visual impairment in adults and children.