Isolation and Expansion of Muscle Precursor Cells from Human Skeletal Muscle Biopsies

Effects of mitochondrial dysfunction on bone metabolism and related diseases: a scientometric study from 2003 to 2022

Background

In recent years, mitochondrial dysfunction has been extensively studied and published, but research on the effects of mitochondrial dysfunction on bone metabolism and related diseases is only just beginning. Furthermore, no studies have been carried out to systematically illustrate this area from a scientometric point of view. The goal of this research is to review existing knowledge and identify new trends and possible hotspots in this area.

Methods

All publications related to the relationship between mitochondrial dysfunction and bone metabolism and related diseases from 2003 to 2022 were searched at the Web of Science Core Collection (WoSCC) on May 7, 2022. Four different analytical tools: VOSviewer 1.6.18, CiteSpace V 6.1, HistorCite (12.03.07), and Excel 2021 were used for the scientometric research.

Results

The final analysis included 555 valid records in total. Journal of Biological Chemistry (Co-citations = 916) is the most famous journal in this field. China (Percentage = 37%), the United States (Percentage = 24%), and Korea (Percentage = 12%) are the most productive countries. Blanco FJ and Choi EM are the main researchers with significant academic influence. Current research hotspots are basic research on mitochondrial dysfunction and the prevention or treatment of bone metabolism-related diseases.

Conclusion

The study of the consequences of mitochondrial dysfunction on bone metabolism and associated diseases is advancing rapidly. Several prominent researchers have published extensive literature and are widely cited. Future research in this area will focus on oxidative stress, aging, gene expression, and the pathogenesis of bone metabolism-related diseases.

3D in vitro Models of Pathological Skeletal Muscle: Which Cells and Scaffolds to Elect?

Skeletal muscle is a fundamental tissue of the human body with great plasticity and adaptation to diseases and injuries. Recreating this tissue in vitro helps not only to deepen its functionality, but also to simulate pathophysiological processes. In this review we discuss the generation of human skeletal muscle three-dimensional (3D) models obtained through tissue engineering approaches. First, we present an overview of the most severe myopathies and the two key players involved: the variety of cells composing skeletal muscle tissue and the different components of its extracellular matrix. Then, we discuss the peculiar characteristics among diverse in vitro models with a specific focus on cell sources, scaffold composition and formulations, and fabrication techniques. To conclude, we highlight the efficacy of 3D models in mimicking patient-specific myopathies, deepening muscle disease mechanisms or investigating possible therapeutic effects.

Customized bioreactor enables the production of 3D diaphragmatic constructs influencing matrix remodeling and fibroblast overgrowth

The production of skeletal muscle constructs useful for replacing large defects in vivo, such as in congenital diaphragmatic hernia (CDH), is still considered a challenge. The standard application of prosthetic material presents major limitations, such as hernia recurrences in a remarkable number of CDH patients. With this work, we developed a tissue engineering approach based on decellularized diaphragmatic muscle and human cells for the in vitro generation of diaphragmatic-like tissues as a proof-of-concept of a new option for the surgical treatment of large diaphragm defects. A customized bioreactor for diaphragmatic muscle was designed to control mechanical stimulation and promote radial stretching during the construct engineering. In vitro tests demonstrated that both ECM remodeling and fibroblast overgrowth were positively influenced by the bioreactor culture. Mechanically stimulated constructs also increased tissue maturation, with the formation of new oriented and aligned muscle fibers. Moreover, after in vivo orthotopic implantation in a surgical CDH mouse model, mechanically stimulated muscles maintained the presence of human cells within myofibers and hernia recurrence did not occur, suggesting the value of this approach for treating diaphragm defects.

Sources, Characteristics, and Therapeutic Applications of Mesenchymal Cells in Tissue Engineering

Tissue engineering (TE) is a therapeutic option within regenerative medicine that allows to mimic the original cell environment and functional organization of the cell types necessary for the recovery or regeneration of damaged tissue using cell sources, scaffolds, and bioreactors. Among the cell sources, the utilization of mesenchymal cells (MSCs) has gained great interest because these multipotent cells are capable of differentiating into diverse tissues, in addition to their self-renewal capacity to maintain their cell population, thus representing a therapeutic alternative for those diseases that can only be controlled with palliative treatments. This review aimed to summarize the state of the art of the main sources of MSCs as well as particular characteristics of each subtype and applications of MSCs in TE in seven different areas (neural, osseous, epithelial, cartilage, osteochondral, muscle, and cardiac) with a systemic revision of advances made in the last 10 years. It was observed that bone marrow-derived MSCs are the principal type of MSCs used in TE, and the most commonly employed techniques for MSCs characterization are immunodetection techniques. Moreover, the utilization of natural biomaterials is higher (41.96%) than that of synthetic biomaterials (18.75%) for the construction of the scaffolds in which cells are seeded. Further, this review shows alternatives of MSCs derived from other tissues and diverse strategies that can improve this area of regenerative medicine.

Enhancing Interrogation of Skeletal Muscle Samples for Informative Quantitative Data

Careful quantitative analysis of histological preparations of muscle samples is crucial to accurate investigation of myopathies in man and of interpretation of data from animals subjected to experimental or potentially therapeutic treatments. Protocols for measuring cell numbers are subject to problems arising from biases associated with preparative and analytical techniques. Prominent among these is the effect of polarized structure of skeletal muscle on sampling bias. It is also common in this tissue to collect data as ratios to convenient reference dominators, the fundamental bases of which are ill-defined, or unrecognized or not accurately assessable. Use of such 'floating' denominators raises a barrier to estimation of the absolute values that assume practical importance in medical research, where accurate comparison between different scenarios in different species is essential to the aim of translating preclinical research findings in animal models to clinical utility in Homo sapiens.This review identifies some of the underappreciated problems with current morphometric practice, some of which are exacerbated in skeletal muscle, and evaluates the extent of their intrusiveness into the of building an objective, accurate, picture of the structure of the muscle sample. It also contains recommendations for eliminating or at least minimizing these problems. Principal among these, would be the use of stereological procedures to avoid the substantial counting biases arising from inter-procedure differences in object size and section thickness.Attention is also drawn to the distortions of interpretation arising from use of undefined or inappropriate denominators.

Rhabdomyosarcoma Cells Produce Their Own Extracellular Matrix With Minimal Involvement of Cancer-Associated Fibroblasts: A Preliminary Study

BACKGROUND

The interplay between neoplastic cells and surrounding extracellular matrix (ECM) is one of the determinant elements for cancer growth. The remodeling of the ECM by cancer-associated fibroblasts (CAFs) shapes tumor microenvironment by depositing and digesting ECM proteins, hence promoting tumor growth and invasion. While for epithelial tumors CAFs are well characterized, little is known about the stroma composition of mesenchymal cancers, such as in rhabdomyosarcoma (RMS), the most common soft tissue sarcoma during childhood and adolescence. The aim of this work is to identify the importance of CAFs in specifying RMS microenvironment and the role of these stromal cells in RMS growth.

METHODS

We assessed in two dimensional (2D) and three dimensional (3D) systems the attraction between RMS cells and fibroblasts using epithelial colon cancer cell line as control. CAFs were studied in a xenogeneic mouse model of both tumor types and characterized in terms of fibroblast activation protein (FAP), mouse PDGFR expression, metalloproteases activation, and ECM gene and protein expression profiling.

RESULTS

In 2D model, the rate of interaction between stromal and malignant cells was significantly lower in RMS with respect to colon cancer. Particularly, in 3D system, RMS spheroids tended to dismantle the compact aggregate when grown on the layer of stromal cells. In vivo, despite the well-formed tumor mass, murine CAFs were found in low percentage in RMS xenogeneic samples.

CONCLUSIONS

Our findings support the evidence that, differently from epithelial cancers, RMS cells are directly involved in their own ECM remodeling, and less dependent on CAFs support for cancer cell growth.

Coding Cell Identity of Human Skeletal Muscle Progenitor Cells Using Cell Surface Markers: Current Status and Remaining Challenges for Characterization and Isolation

Skeletal muscle progenitor cells (SMPCs), also called myogenic progenitors, have been studied extensively in recent years because of their promising therapeutic potential to preserve and recover skeletal muscle mass and function in patients with cachexia, sarcopenia, and neuromuscular diseases. SMPCs can be utilized to investigate the mechanisms of natural and pathological myogenesis via in vitro modeling and in vivo experimentation. While various types of SMPCs are currently available from several sources, human pluripotent stem cells (PSCs) offer an efficient and cost-effective method to derive SMPCs. As human PSC-derived cells often display varying heterogeneity in cell types, cell enrichment using cell surface markers remains a critical step in current procedures to establish a pure population of SMPCs. Here we summarize the cell surface markers currently being used to detect human SMPCs, describing their potential application for characterizing, identifying and isolating human PSC-derived SMPCs. To date, several positive and negative markers have been used to enrich human SMPCs from differentiated PSCs by cell sorting. A careful analysis of current findings can broaden our understanding and reveal potential uses for these surface markers with SMPCs.

Generation of a Functioning and Self-Renewing Diaphragmatic Muscle Construct

Surgical repair of large muscular defects requires the use of autologous graft transfer or prosthetic material. Naturally derived matrices are biocompatible materials obtained by tissue decellularization and are commonly used in clinical practice. Despite promising applications described in the literature, the use of acellular matrices to repair large defects has been only partially successful, highlighting the need for more efficient constructs. Scaffold recellularization by means of tissue engineering may improve not only the structure of the matrix, but also its ability to functionally interact with the host. The development of such a complex construct is challenging, due to the complexity of the native organ architecture and the difficulties in recreating the cellular niche with both proliferative and differentiating potential during growth or after damage. In this study, we tested a mouse decellularized diaphragmatic extracellular matrix (ECM) previously described by our group, for the generation of a cellular skeletal muscle construct with functional features. The decellularized matrix was stored using different conditions to mimic the off‐the‐shelf clinical need. Pediatric human muscle precursors were seeded into the decellularized scaffold, demonstrating proliferation and differentiation capability, giving rise to a functioning three‐dimensional skeletal muscle structure. Furthermore, we exposed the engineered construct to cardiotoxin injury and demonstrated its ability to activate a regenerative response in vitro promoting cell self‐renewal and a positive ECM remodeling. Functional reconstruction of an engineered skeletal muscle with maintenance of a stem cell pool makes this a promising tool toward future clinical applications in diaphragmatic regeneration. stem cells translational medicine2019;8:858&869

Muscle stem cells: what's new in orthopedics?

BACKGROUND AND AIM OF THE WORK

Adult stem cells were studied as a source of potentially useful development for tissue engineering and repair techniques. The aim of this review is to clarify the actual and possible uses of muscle stem cells in orthopedics.

METHODS

A selection of studies was made to obtain a homogeneous and up to date overview on the muscle stem cells applications.

RESULTS

In recent years muscle was studied as a good source of adult stem cells that can differentiate into different cell lineages. Muscle stem cells are a heterogeneous population of cells, which demonstrated in vitro a great potential for the regeneration and repair of muscle, bone and cartilage tissue. Among muscle stem cells, satellite stem cells are the most known progenitor cells: they can differentiate in osteoblasts, adipocytes, chondrocytes and myocytes.

CONCLUSIONS

Although muscle stem cells are a promising field of research, more pre-clinical studies in animal models are still needed to determine the safety and efficiency of the transplant procedures in humans.

Alcohol exposure decreases osteopontin expression during fracture healing and osteopontin-mediated mesenchymal stem cell migration in vitro

BACKGROUND

Alcohol consumption is a risk factor for impaired fracture healing, though the mechanism(s) by which this occurs are not well understood. Our laboratory has previously shown that episodic alcohol exposure of rodents negatively affects fracture callus development, callus biomechanics, and cellular signaling which regulates stem cell differentiation. Here, we examine whether alcohol alters chemokine expression and/or signaling activity in the mouse fracture callus during early fracture healing.

METHODS

A mouse model for alcohol-impaired tibia fracture healing was utilized. Early fracture callus was examined for alcohol-effects on tissue composition, expression of chemokines involved in MSC migration to the fracture site, and biomechanics. The effects of alcohol on MSC migration and cell adhesion receptors were examined in an in vitro system.

RESULTS

Mice exposed to alcohol showed decreased evidence of external callus formation, decreased callus-related osteopontin (OPN) expression levels, and decreased biomechanical stiffness. Alcohol exposure decreased rOPN-mediated MSC migration and integrin β1 receptor expression in vitro.

CONCLUSIONS

The effects of alcohol exposure demonstrated here on fracture callus-associated OPN expression, rOPN-mediated MSC migration in vitro, and MSC integrin β1 receptor expression in vitro have not been previously reported. Understanding the effects of alcohol exposure on the early stages of fracture repair may allow timely initiation of treatment to mitigate the long-term complications of delayed healing and/or fracture non-union.