Nanoengineered myogenic scaffolds for skeletal muscle tissue engineering

Here, we developed a nano-engineered biomaterial optimized for skeletal muscle proliferation and differentiation. Nanoclay disks were used to control the release of insulin-like growth factor (IGF-1), a key myogenic and immunogenic regulator.

Differential Gene Expression in Cell Types of the Human Skeletal Muscle: A Bioinformatics-Based Meta-Review

PURPOSE: This study evaluates the differences in the expression of genes frequently analyzed in the field of exercise science between the skeletal muscle tissue and various cell types that comprise the skeletal muscle tissue.METHODS: We summarized the genes and proteins expressed in the skeletal muscle that were published in “Exercise Science” journal from 2015 to present. Thereafter, we selected 15 genes and proteins that were the most analyzed genes and proteins in the skeletal muscle. These genes and proteins were horizontally compared for expression differences in skeletal muscle components and cultured cells based on NCBI Gene Expression Omnibus DataSets.RESULTS: The most analyzed genes (encoding analyzed proteins) in skeletal muscle tissues in “Exercise Science” were PPARGC1A, PPARD, MTOR, MAP1LC3A, MAP1LC3B, PRKAA1, AKT1, SLC2A4, MAPK1, COX4I1, MAPK14, MEF2A, MAPK8, RPS6KB1, and SOD1. Among them, PPARGC1A, AKT1, SLC2A4, MAPK1, and COX4I1 were specifically expressed in the skeletal muscle. However, expression of other genes was found to be significantly affected in other cell types of the skeletal muscle tissue.CONCLUSIONS: Genes such as PPARGC1A, which are specifically expressed in the skeletal muscle, may be analyzed without pretreating (such as perfusion) the skeletal muscle tissue. However, expression of other genes may depend on the skeletal muscle cell type. Thus, in such instances, pretreatment, such as perfusion and isolation, should be considered.

A Cylindrical Molding Method for the Biofabrication of Plane-Shaped Skeletal Muscle Tissue

Muscle tissues can be fabricated in vitro by culturing myoblast-populated hydrogels. To counter the shrinkage of the myoblast-populated hydrogels during culture, a pair of anchors are generally utilized to fix the two ends of the hydrogel. Here, we propose an alternative method to counter the shrinkage of the hydrogel and fabricate plane-shaped skeletal muscle tissues. The method forms myoblast-populated hydrogel in a cylindrical cavity with a central pillar, which can prevent tissue shrinkage along the circumferential direction. By eliminating the usages of the anchor pairs, our proposed method can produce plane-shaped skeletal muscle tissues with uniform width and thickness. In experiments, we demonstrate the fabrication of plane-shaped (length: ca. 10 mm, width: 5~15 mm) skeletal muscle tissue with submillimeter thickness. The tissues have uniform shapes and are populated with differentiated muscle cells stained positive for myogenic differentiation markers (i.e., myosin heavy chains). In addition, we show the assembly of subcentimeter-order tissue blocks by stacking the plane-shaped skeletal muscle tissues. The proposed method can be further optimized and scaled up to produce cultured animal products such as cultured meat.

Controllable assembly of skeletal muscle-like bundles through 3D bioprinting

3D printing is an effective technology for recreating skeletal muscle tissue in vitro. To achieve clinical skeletal muscle injury repair, relatively large volumes of highly aligned skeletal muscle cells are required; obtaining these is still a challenge. It is currently unclear how individual skeletal muscle cells and their neighbouring components co-ordinate to establish anisotropic architectures in highly homogeneous orientations. Here, we demonstrated a 3D printing strategy followed by sequential culture processes to engineer skeletal muscle tissue. The effects of confined printing on the skeletal muscle during maturation, which impacted the myotube alignment, myogenic gene expression, and mechanical forces, were observed. Our findings demonstrate the dynamic changes of skeletal muscle tissue during in vitro 3D construction and reveal the role of physical factors in the orientation and maturity of muscle fibres.

Impact of Pre-Mortem Factors on Meat Quality: An Update

Meat quality is closely associated with the chemical composition of skeletal muscle and is therefore influenced by the pre-mortem metabolic state of skeletal muscle tissue [...]

Recent Trends in Biofabrication Technologies for Studying Skeletal Muscle Tissue-Related Diseases

In native skeletal muscle, densely packed myofibers exist in close contact with surrounding motor neurons and blood vessels, which are embedded in the fibrous connective tissue. In comparison to conventional two-dimensional (2D) cultures, the three-dimensional (3D) engineered skeletal muscle models allow structural and mechanical resemblance with native skeletal muscle tissue by providing geometric confinement and physiological matrix stiffness to the cells. In addition, various external stimuli applied to these models enhance muscle maturation along with cell–cell and cell–extracellular matrix interaction. Therefore, 3D in vitro muscle models can adequately recapitulate the pathophysiologic events occurring in tissue–tissue interfaces inside the native skeletal muscle such as neuromuscular junction. Moreover, 3D muscle models can induce pathological phenotype of human muscle dystrophies such as Duchenne muscular dystrophy by incorporating patient-derived induced pluripotent stem cells and human primary cells. In this review, we discuss the current biofabrication technologies for modeling various skeletal muscle tissue-related diseases (i.e., muscle diseases) including muscular dystrophies and inflammatory muscle diseases. In particular, these approaches would enable the discovery of novel phenotypic markers and the mechanism study of human muscle diseases with genetic mutations.