ABSTRACT
Extracellular matrix (ECM) pathologic remodeling underlies many disorders, including muscular dystrophy. Tissue decellularization removes cellular components while leaving behind ECM components. We generated "on-slide" decellularized tissue slices from genetically distinct dystrophic mouse models. The ECM of dystrophin- and sarcoglycan-deficient muscles had marked thrombospondin 4 deposition, while dysferlin-deficient muscle had excess decorin. Annexins A2 and A6 were present on all dystrophic decellularized ECMs, but annexin matrix deposition was excessive in dysferlin-deficient muscular dystrophy. Muscle-directed viral expression of annexin A6 resulted in annexin A6 in the ECM. C2C12 myoblasts seeded onto decellularized matrices displayed differential myoblast mobility and fusion. Dystrophin-deficient decellularized matrices inhibited myoblast mobility, while dysferlin-deficient decellularized matrices enhanced myoblast movement and differentiation. Myoblasts treated with recombinant annexin A6 increased mobility and fusion like that seen on dysferlin-deficient decellularized matrix and demonstrated upregulation of ECM and muscle cell differentiation genes. These findings demonstrate specific fibrotic signatures elicit effects on myoblast activity.
Subject(s)
Cell Differentiation , Cell Movement , Dysferlin , Extracellular Matrix , Myoblasts , Sarcoglycans , Animals , Myoblasts/metabolism , Myoblasts/cytology , Extracellular Matrix/metabolism , Mice , Sarcoglycans/genetics , Sarcoglycans/metabolism , Dysferlin/genetics , Dysferlin/metabolism , Muscular Dystrophies/genetics , Muscular Dystrophies/metabolism , Muscular Dystrophies/pathology , Dystrophin/genetics , Dystrophin/metabolism , Annexin A2/genetics , Annexin A2/metabolism , Decorin/genetics , Decorin/metabolism , Cell Line , Disease Models, Animal , Muscle, Skeletal/metabolismABSTRACT
The Murphy Roths Large (MRL) mouse strain has "super-healing" properties that enhance recovery from injury. In mice, the DBA/2J strain intensifies many aspects of muscular dystrophy, so we evaluated the ability of the MRL strain to suppress muscular dystrophy in the Sgcg-null mouse model of limb girdle muscular dystrophy. A comparative analysis of Sgcg-null mice in the DBA/2J versus MRL strains showed greater myofiber regeneration, with reduced structural degradation of muscle in the MRL strain. Transcriptomic profiling of dystrophic muscle indicated strain-dependent expression of extracellular matrix (ECM) and TGF-ß signaling genes. To investigate the MRL ECM, cellular components were removed from dystrophic muscle sections to generate decellularized myoscaffolds. Decellularized myoscaffolds from dystrophic mice in the protective MRL strain had significantly less deposition of collagen and matrix-bound TGF-ß1 and TGF-ß3 throughout the matrix. Dystrophic myoscaffolds from the MRL background, but not the DBA/2J background, were enriched in myokines like IGF-1 and IL-6. C2C12 myoblasts seeded onto decellularized matrices from Sgcg-/- MRL and Sgcg-/- DBA/2J muscles showed the MRL background induced greater myoblast differentiation compared with dystrophic DBA/2J myoscaffolds. Thus, the MRL background imparts its effect through a highly regenerative ECM, which is active even in muscular dystrophy.
Subject(s)
Muscular Dystrophies, Limb-Girdle , Muscular Dystrophies , Mice , Animals , Mice, Inbred DBA , Muscular Dystrophies/genetics , Muscles , Extracellular Matrix , Mice, KnockoutABSTRACT
Genetic background shifts the severity of muscular dystrophy. In mice, the DBA/2J strain confers a more severe muscular dystrophy phenotype, whereas the Murphy's Roth Large (MRL) strain has "super-healing" properties that reduce fibrosis. A comparative analysis of the Sgcg null model of Limb Girdle Muscular Dystrophy in the DBA/2J versus MRL strain showed the MRL background was associated with greater myofiber regeneration and reduced structural degradation of muscle. Transcriptomic profiling of dystrophic muscle in the DBA/2J and MRL strains indicated strain-dependent expression of the extracellular matrix (ECM) and TGF-ß signaling genes. To investigate the MRL ECM, cellular components were removed from dystrophic muscle sections to generate decellularized "myoscaffolds". Decellularized myoscaffolds from dystrophic mice in the protective MRL strain had significantly less deposition of collagen and matrix-bound TGF-ß1 and TGF-ß3 throughout the matrix, and dystrophic myoscaffolds from the MRL background were enriched in myokines. C2C12 myoblasts were seeded onto decellularized matrices from Sgcg-/- MRL and Sgcg-/- DBA/2J matrices. Acellular myoscaffolds from the dystrophic MRL background induced myoblast differentiation and growth compared to dystrophic myoscaffolds from the DBA/2J matrices. These studies establish that the MRL background also generates its effect through a highly regenerative ECM, which is active even in muscular dystrophy.
ABSTRACT
Objective: Guyana is located on the north coast of the South American continent and is a middle-income developing country in the Caribbean. There is little educational opportunity for individuals interested in medical acupuncture. The aim of this project was to develop an introductory medical acupuncture curriculum for perioperative use. Materials and Methods: Through a carefully coordinated teaching-and-care plan, with support from physicians and various medical organizations, an educational opportunity in medical acupuncture was established at the Georgetown Public Hospital Corporation, a medical university teaching hospital in Georgetown, Guyana. The project involved development of a medical acupuncture curriculum, as well as teaching and patient care. Anesthesia staff members, resident trainees, and perioperative and pain-clinic patients participated. Results: Medical acupuncture-trained physicians were able to provide medical acupuncture education and services in a third-world country because of this project. Conclusion: This project is an ideal example of utilizing medical acupuncture for promoting global heath.
ABSTRACT
PURPOSE: Attaining lung isolation in the infant undergoing thoracic anesthesia can be challenging for the anesthesiologist. We describe a novel approach to performing lung isolation in an infant undergoing thoracotomy for lobectomy using an Arndt pediatric endobronchial blocker via an extraluminal technique. CLINICAL FEATURES: Lung isolation in an infant was achieved through the use of an Arndt pediatric endobronchial blocker placed externally to an endotracheal tube. The blocker's placement was facilitated through the use of a pediatric fibreoptic brochoscope placed through the guidewire of the extraluminally placed bronchial blocker. CONCLUSION: This novel technique may provide an easier and more reliable method of attaining single lung ventilation in infants and small children.
