Muscle acellular scaffold as a biomaterial: Effects on C2C12 cell differentiation and interaction with the murine host environment

The extracellular matrix (ECM) of decellularized organs possesses the characteristics of the ideal tissue-engineering scaffold (i.e., histocompatibility, porosity, degradability, non-toxicity). We previously observed that the muscle acellular scaffold (MAS) is a pro-myogenic environmentin vivo. In order to determine whether MAS, which is basically muscle ECM, behaves as a myogenic environment, regardless of its location, we analyzed MAS interaction with both muscle and non-muscle cells and tissues, to assess the effects of MAS on cell differentiation. Bone morphogenetic protein treatment of C2C12 cells cultured within MAS induced osteogenic differentiation in vitro, thus suggesting that MAS does not irreversibly commit cells to myogenesis.In vivo MAS supported formation of nascent muscle fibers when replacing a muscle (orthotopic position). However, heterotopically grafted MAS did not give rise to muscle fibers when transplanted within the renal capsule. Also, no muscle formation was observed when MAS was transplanted under the xiphoid process, in spite of the abundant presence of cells migrating along the laminin-based MAS structure. Taken together, our results suggest that MAS itself is not sufficient to induce myogenic differentiation. It is likely that the pro-myogenic environment of MAS is not strictly related to the intrinsic properties of the muscle scaffold (e.g., specific muscle ECM proteins). Indeed, it is more likely that myogenic stem cells colonizing MAS recognize a muscle environment that ultimately allows terminal myogenic differentiation. In conclusion, MAS may represent a suitable environment for muscle and non-muscle 3D constructs characterized by a highly organized structure whose relative stability promotes integration with the surrounding tissues. Our work highlights the plasticity of MAS, suggesting that it may be possible to consider MAS for a wider range of tissue engineering applications than the mere replacement of volumetric muscle loss

Molecular, cellular and physiological characterization of the cancer cachexia-inducing C26 colon carcinoma in mouse

BACKGROUND: The majority of cancer patients experience dramatic weight loss, due to cachexia and consisting of skeletal muscle and fat tissue wasting. Cachexia is a negative prognostic factor, interferes with therapy and worsens the patients' quality of life by affecting muscle function. Mice bearing ectopically-implanted C26 colon carcinoma are widely used as an experimental model of cancer cachexia. As part of the search for novel clinical and basic research applications for this experimental model, we characterized novel cellular and molecular features of C26-bearing mice. METHODS: A fragment of C26 tumor was subcutaneously grafted in isogenic BALB/c mice. The mass growth and proliferation rate of the tumor were analyzed. Histological and cytofluorometric analyses were used to assess cell death, ploidy and differentiation of the tumor cells. The main features of skeletal muscle atrophy, which were highlighted by immunohistochemical and electron microscopy analyses, correlated with biochemical alterations. Muscle force and resistance to fatigue were measured and analyzed as major functional deficits of the cachectic musculature. RESULTS: We found that the C26 tumor, ectopically implanted in mice, is an undifferentiated carcinoma, which should be referred to as such and not as adenocarcinoma, a common misconception. The C26 tumor displays aneuploidy and histological features typical of transformed cells, incorporates BrdU and induces severe weight loss in the host, which is largely caused by muscle wasting. The latter appears to be due to proteasome-mediated protein degradation, which disrupts the sarcomeric structure and muscle fiber-extracellular matrix interactions. A pivotal functional deficit of cachectic muscle consists in increased fatigability, while the reported loss of tetanic force is not statistically significant following normalization for decreased muscle fiber size. CONCLUSIONS: We conclude, on the basis of the definition of cachexia, that ectopically-implanted C26 carcinoma represents a well standardized experimental model for research on cancer cachexia. We wish to point out that scientists using the C26 model to study cancer and those using the same model to study cachexia may be unaware of each other's works because they use different keywords; we present strategies to eliminate this gap and discuss the benefits of such an exchange of knowledge

The pro-myogenic environment provided by whole organ scale acellular scaffolds from skeletal muscle.

In the pursuit of a transplantable construct for the replacement of large skeletal muscle defects arising from traumatic or pathological conditions, several attempts have been made to obtain a highly oriented, vascularized and functional skeletal muscle. Acellular scaffolds derived from organ decellularization are promising, widely used biomaterials for tissue engineering. However, the acellular skeletal muscle extra cellular matrix (ECM) has been poorly characterized in terms of production, storage and hoste-donor interactions.We have produced acellular scaffolds at the whole organ scale from various skeletal muscles explanted from mice. The acellular scaffolds conserve chemical and architectural features of the tissue of origin, including the vascular bed. Scaffolds can be sterilely stored for weeks at þ4 C or þ37 C in tissue culture grade conditions. When transplanted in wt mice, the grafts are stable for several weeks, whilst being colonized by inflammatory and stem cells. We demonstrate that the acellular scaffold per se represents a pro-myogenic environment supporting de novo formation of muscle fibers, likely derived from host cells with myogenic potential. Myogenesis within the implant is enhanced by immunosuppressive treatment. Our work highlights the fundamental role of this niche in tissue engineering application and unveils the clinical potential of allografts based on decellularized tissue for regenerative medicine

Bridging Graduate Education in Public Health and the Liberal Arts

The University of Massachusetts Amherst is part of Five-Colleges Inc, a consortium that includes the university and four liberal arts colleges. Consortium faculty from the School of Public Health and Health Sciences at the university and from the colleges are working to bridge liberal arts with public health graduate education. We outline four key themes guiding this effort and exemplary curricular tools for innovative community-based and multidisciplinary academic and research programs. The structure of the consortium has created a novel trajectory for student learning and engagement, with important ramifications for pedagogy and professional practice in public health. We show how graduate public health education and liberal arts can, and must, work in tandem to transform public health practice in the 21st century

Decellularized scaffolds from skeletal muscle are a suitable environment for myogenesis in vivo

Background. Skeletal muscle defects arising from traumatic or pathological conditions may require surgical interventions. In our previous studies we described the interactions between a decellularized scaffold derived from a murine skeletal muscle and an isogenic mouse host. Our research is focused on the interaction of the grafted scaffold with other tissues, i.e immune and nervous systems. In addition, we aim to build off-the-shelf, transplantable constructs by culturing myogenic cells into the scaffold before transplantation. Methods. We decellularized Tibialis Anterior muscle of cadaveric origin. The decellularization process was achieved by incubation of dissected muscles in a detergent solution. To replace homologous muscles, we orthotopically transplanted decellularized scaffolds, by suturing them to the host tendon extremities following TA removal. With this approach the constructs were analyzed in regard to histocompatibility, bioactivity, degradability, toxicity in vivo at different times from transplantation. Alternatively, before transplantation the scaffolds were pre-seeded with myogenic cells in vitro. Results and conclusions. The procedure to produce acellular scaffolds from cadaveric skeletal muscles preserves the extracellular matrix and its anatomical pattern. The transplanted acellular scaffold is readily colonized by both inflammatory and myogenic stem cells, as demonstrated by the expression of stem cell markers, followed by the formation of muscle fibers. The latter show centrally located nuclei and express muscle-specific myosin. Cytofluorimetric analysis of the inflammatory cells population shows that CD45+ cells are mostly represented by macrophages, even though T lymphocytes and granulocytes are also present. So likely macrophages play a major role in acellular muscle graft integration and remodeling. Functionality of skeletal muscle is strictly dependent on myofibers spatial orientation and on innervation. Preliminary data suggest the presence of neuro-muscular junctions in the proximity of the cells that populate the grafted scaffold, suggesting the potential for re-innervation of the implant. The integration of the scaffold can likely be boosted by previous myogenic cell colonization, so we delivered satellite cells to the acellular scaffolds and noted the formation of muscle fibers into the construct in culture. Our studies show that scaffolds derived from decellularized muscles are a highly myogenic environment and may represent an innovative tool for skeletal muscle regenerative medicine

Decellularized scaffolds from skeletal muscle are suitable environment for myogenesis in vivo

Background. Skeletal muscle loss secondary to trauma or myopathy may require surgical interventions, i.e. muscle transplant or transposition. Our approach for skeletal muscle tissue engineering is based on a decellularized scaffold derived from a murine skeletal muscle of cadaveric origin. Our goal is the preparation of an implantable scaffold for applications in muscle repair surgical intervention. Methods. We decellularized the Tibialis Anterior (TA) muscle of cadaveric origin from murine hindlimbs. The decellularization process was achieved by incubation of dissected muscles in a detergent solution for different times accordingly to the muscle size. To assess biocompatibility, cell-loaded scaffolds were initially cultured in growth medium (i.e. containing high serum) followed by incubation in a differentiative medium (i.e. containing low serum), and cell viability was assessed by incorporation of the vital dye CMFDA. To replace homologous muscles, we transplanted decellularized scaffolds in vivo, by suturing them to the host tendon extremities following TA removal. The same protocol of transplantation was applied to implants derived from wild type mice in place of the homologous muscle in Nude mice (wt/Nude). With this approach the constructs were analyzed in regard to histocompatibility, bioactivity, degradability, toxicity in vivo at different times from transplantation. Results and discussion. The procedure to produce acellular scaffolds from cadaveric skeletal muscles preserves the extracellular matrix and its anatomical pattern. These scaffolds are suitable for myoblast cell culture in vitro and the cells are viable for several days. Both wt/wt mice and wt/Nude mice transplantation studies demonstrate that scaffolds are biodegradable in vivo in four weeks. Nonetheless, the transplanted acellular scaffold is readily colonized by both inflammatory and myogenic stem cells, as demonstrated by the expression of stem cell markers, followed by the formation of muscle fibers. The latter show centrally located nuclei and express muscle-specific myosin. Our studies represent the first molecular characterization of in vivo bioactivity of scaffolds derived from decellularized muscles and demonstrate that acellular scaffolds represent an innovative tool for the reconstruction of missing muscles

Muscle extracellular matrix scaffold is a multipotent environment

The multipotency of scaffolds is a new concept. Skeletal muscle acellular scaffolds (MAS) implanted at the interface of Tibialis Anterior/tibial bone and masseter muscle/mandible bone in a murine model were colonized by muscle cells near the host muscle and by bone-cartilaginous tissues near the host bone, thus highlighting the importance of the environment in directing cell homing and differentiation. These results unveil the multipotency of MAS and point to the potential of this new technique as a valuable tool in musculo-skeletal tissue regeneration

Can modification of cell physiology and growth characteristics by static magnetic field have therapeutic applications?

There is continuing progress in studies of the effect of static magnetic field (SMF) on cell growth in vivo and in vitro. The evidence in the literature including our studies indicates that SMF exerts significant effects on some physiological functions of the cell and affects their growth pattern and morphometry. This prompts us to question as to whether these effects can have therapeutic use. In the present study we demonstrate that SMF is able to modulate cell growth and differentiation in myogenic cultured cells as demonstrated by increased accumulation of actin and myosin and formation of large multinucleated myotubes. SMF is also able to spatially orient skeletal muscle cells growing on cysteamine-coated gold. Such SMF effects may have significant practical applications in tissue engineering, in particular for culturing skeletal muscle cells on conductive surfaces that is required to develop electronic device-muscle junctions for experimental and medical applications. Furthermore, SMF-enhanced parallel orientation of myotubes is relevant to tissue engineering of a highly organized tissue such as skeletal muscle. In the present study we also show that SMF produces functional changes as well. Specifically, we observe that constitutive- and exogenous oxidant- induced phosphorylation of histone H2AX and activation of ATM-S1981, the reporters of DNA damage response in human leukemic TK6 cells, are attenuated by SMF. Also, in glioblastoma cells SMF is able to modulate radiation induced DNA damage as demonstrated by comet assay. If this protective effect of SMF on DNA damage is confirmed and there is absence of potential side effects, one may consider the use of SMF for treatment of degenerative diseases such as neurodegeneration and muscle wasting thereby introducing a new therapeutic modality in regenerative and inflammation medicine

ACR Appropriateness Criteria \u3csup\u3e®\u3c/sup\u3e Suspected Spine Trauma

© 2019 American College of Radiology Injuries to the cervical and thoracolumbar spine are commonly encountered in trauma patients presenting for treatment. Cervical spine injuries occur in 3% to 4% and thoracolumbar fractures in 4% to 7% of blunt trauma patients presenting to the emergency department. Clear, validated criteria exist for screening the cervical spine in blunt trauma. Screening criteria for cervical vascular injury and thoracolumbar spine injury have less validation and widespread acceptance compared with cervical spine screening. No validated criteria exist for screening of neurologic injuries in the setting of spine trauma. CT is preferred to radiographs for initial assessment of spine trauma. CT angiography and MR angiography are both acceptable in assessment for cervical vascular injury. MRI is preferred to CT myelography for assessing neurologic injury in the setting of spine trauma. MRI is usually appropriate when there is concern for ligament injury or in screening obtunded patients for cervical spine instability. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment