1,721,050 research outputs found
Muscle tissue engineering
No full textSkeletal muscle tissue engineering is relatively new field exploiting knowledge of histology, cell biology, medicine, chemistry and engineering to regenerate, reconstruct and replace damaged or lost muscles. The detailed picture of the muscle histophysiology, the characteristic organization of the muscular tissue and the influence of specific location (cell niche) on muscle stem cell behaviour explain the rationale of limited results obtained so far to mimic this complex architecture organization of the skeletal muscle tissue. Nevertheless the novel approaches through new muscle progenitor/stem cell consciousness together with modern three-dimensional cell culture systems relying on innovative material scaffold guaranteeing versatility, cell adhesion, cell survival and muscle differentiation, offer a completely new scenario for the future application of these biotechnology for the treatment of muscle degenerating affected individual
Cell lineage tracing during Xenopus tail regeneration
No full textThe tail of the Xenopus tadpole will regenerate following amputation, and all three of the main axial structures - the spinal cord, the notochord and the segmented myotomes are found in the regenerated tail. We have investigated the cellular origin of each of these three tissue types during regeneration.We produced Xenopus laevis embryos transgenic for the CMV (Simian Cytomegalovirus) promoter driving GFP (Green Fluorescent Protein) ubiquitously throughout the embryo. Single tissues were then specifically labelled by making grafts at the neurula stage from transgenic donors to unlabelled hosts. When the hosts have developed to tadpoles, they carry a region of the appropriate tissue labelled with GFP. These tails were amputated through the labelled region and the distribution of labelled cells in the regenerate was followed. We also labelled myofibres using the Cre-lox method.The results show that the spinal cord and the notochord regenerate from the same tissue type in the stump, with no labelling of other tissues. In the case of the muscle, we show that the myofibres of the regenerate arise from satellite cells and not from the pre-existing myofibres. This shows that metaplasia between differentiated cell types does not occur, and that the process of Xenopus tail regeneration is more akin to tissue renewal in mammals than to urodele tail regeneration
Could a functional artificial skeletal muscle be useful in muscle wasting?
No full textPurpose of reviewRegardless of the underlying cause, skeletal muscle wasting is detrimental for a person's life quality, leading to impaired strength, locomotion, and physiological activity. Here, we propose a series of studies presenting tissue engineering-based approaches to reconstruct artificial muscle in vitro and in vivo.Recent findingsSkeletal muscle tissue engineering is attracting more and more attention from scientists, clinicians, patients, and media, thanks to the promising results obtained in the last decade with animal models of muscle wasting. The use of novel and refined biomimetic scaffolds mimicking three-dimensional muscle environment, thus supporting cell survival and differentiation, in combination with well characterized myogenic stem/progenitor cells, revealed the noteworthy potential of these technologies for creating artificial skeletal muscle tissue. In vitro, the production of three-dimensional muscle structures offer the possibility to generate a drug-screening platform for patient-specific pharmacological treatment, opening new frontiers in the development of new compounds with specific therapeutic actions. In vivo, three-dimensional artificial muscle biomimetic constructs offer the possibility to replace, in part or entirely, wasted muscle by means of straight reconstruction and/or by enhancing endogenous regeneration.SummaryReports of tissue engineering approaches for artificial muscle building appeared in large numbers in the specialized press lately, advocating the suitability of this technology for human application upon scaling up and a near future applicability for medical care of muscle wasting.Video abstracthttp://links.lww.com/COCN/A
Comparison of Four Different Preparation Methods for Making Injectable Microgels for Tissue Engineering and Cell Therapy
No full textPurpose One of the major challenges in cell-laden microgel bioprocessing is to design an effective method of cell encapsulation in the biomaterial carrier while retaining high cell viability and ensuring small enough particles for injectability. In this study we aim to compare four bioprocessing techniques for making hydrogel microcarriers, including by emulsification gelation and dropwise gelation approaches. Methods A Pluronic-Fibrinogen (FF-127) hydrogel biomaterial was used to make the microgels based on a lower critical solubility temperature (LSCT) phase transition. Additional cross-linking of the hydrogels was achieved using light-activated photochemistry (i.e., photopolymerization). The four bioprocessing methodologies include emulsification gelation in oil (with and without dual photo-initiator free-radical polymerization), reverse thermal gelation (in warm cell culture media), dropwise gelation through a vibrating needle device, and dropwise gelation through an atomization device (in warm cell culture media gelation baths). The microgels made with each method were characterized with and without cells; comparisons of microgel size and cell growth were reported. Results The dual photo-initiator emulsification technique produced FF-127 spherical microgels with an average diameter of 222 and 256 mu m, with and without cells, respectively. The reverse thermal encapsulation produced irregularly shaped microgels with an average diameter of 241 and 702 mu m, with and without cells, respectively. The vibrating needle and atomization techniques produced irregularly shaped microgels with an average diameter of 195 and 151 mu m without cells, respectively, and 464 and 332 mu m with cells, respectively. The viability of fibroblasts in the microgels was high after 24 h, except for those treatments that underwent photo-polymerization (i.e., emulsification photo-polymerization and vibrating needle with photo-polymerization). The cells remained viable for up to 3 weeks in culture and spread three-dimensionally in the microgels over this time course. Conclusions The rapid temperature-induced phase transition of the FF-127 enables the formation of microgels either through dropwise gelation or by emulsification, both through physical cross-linking. The use of a free-radical polymerization cross-linking reaction was more cyto-toxic to the cells as compared to the physical cross-linking by reverse thermal gelation alone. The average microgel size in all the techniques was significantly smaller and more uniform when producing the microgels without cells as compared to with cells. The reverse thermal gelation technique produced cell-laden microgels with the least amount of specialized equipment and bioprocessing steps of all the methods reported. Lay Summary This study provides the framework for producing cell-laden microgels that are of a sufficiently small diameter to be used for injectable cell therapy. The challenge in this regard is to design a simple, scalable, and efficient methods of cell encapsulation in the biomaterials, retaining high cell viability and ensuring small enough particles for injectability. For this purpose, we evaluated four methods that are commonly applied in microgel bioprocessing, and tested these with two types of cells using hydrogels that exhibit lower critical solubility temperature (LCST) properties. This investigation has enabled us to identify advantages and disadvantages for each system of bioprocessing of cell-laden microgels
Matrix scaffolding for stem cell guidance toward skeletal muscle tissue engineering
Full text linkExtracellular matrix (ECM) is composed of many types of fibrous structural proteins and glycosaminoglycans. This important cell component not only provides a support for cells but is also actively involved in cell-cell interaction, proliferation, migration, and differentiation, representing, therefore, no longer only a mere static structural scaffold for cells but rather a dynamic and versatile compartment. This aspect leads to the need for investigating new bio-inspired scaffolds or biomaterials, able to mimic ECM in tissue engineering. This new field of research finds particular employment in skeletal muscle tissue regeneration, due to the inability of this complex tissue to recover volumetric muscle loss (VML), after severe injury. Usually, this is the result of traumatic incidents, tumor ablations, or pathological states that lead to the destruction of a large amount of tissue, including connective tissue and basement membrane. Therefore, skeletal muscle tissue engineering represents a valid alternative to overcome this problem. Here, we described a series of natural and synthetic biomaterials employed as ECM mimics for their ability to recreate the correct muscle stem cell niche, by promoting myogenic stem cell differentiation and so, positively affecting muscle repair
Metabolic reprogramming as therapeutic strategy to ameliorate skeletal muscle tissue engineering procedures
No full textBackground: Stem cells and regenerative medicine raise great expectations
because of the promise to reconstitute aged, injured and diseased tissues. While
success has been achieved for hematological and epithelial diseases, several hur-
dles remain for diseases affecting skeletal and cardiac muscle. Maximizing the sur-
vival and the myogenic activity of the engrafted cells used for tissue engineering
by preconditioning with suitable bioactive molecules would allow better therapeu-
tic outcomes. Notably, energy management and metabolic reprogramming seem to
play a key role in stem cell differentiation. We, therefore, propose that myogenic
precursors preconditioning by metabolic shift induction might potentiate and ame-
liorate the efficacy of reconstructive muscular tissue strategies.
Methodology: We will evaluate the effect of metabolic reprogramming on stem cell
myogenic capabilities and survival and on 3D artificial muscle generation in vitro and in vivo.
Results: Our data show that TMZ exert a profound effect on stem cells, altering
their gene expression profile. It stimulates differentiation of both C2C12 and satel-
lite cells as shown by enhanced expression of muscle-specific genes and proteins
and by higher myotube size and fusion index. Moreover we developed a biotech-
nology demonstrating the possibility to build in vitro and in vivo a complete and
functional artificial muscle in mice.
Conclusions: We expect to select metabolic remodeling agents able to improve
the generation and implantation of artificial muscles. We will also clarify the key
metabolic changes occurring during muscle differentiation, and this will allow further specific therapeutic approaches for muscle replacement
Tissue interactions and lens-forming competence in the outer cornea of larval Xenopus laevis
No full textAfter lentectomy through the pupillary hole, the outer cornea of larval Xenopus laevis can undergo transdifferentiation to regenerate a new lens. This process is elicited by inductive factor(s) produced by the neural retina and accumulated into the vitreous chamber. During embryogenesis, the outer cornea develops from the outer layer of the presumptive lens ectoderm (PLE) under the influence of the eye cup and the lens. In this study, we investigated whether the capacity of the outer cornea to regenerate a lens is the result of early inductive signals causing lens-forming bias and lens specification of the PLE, or late inductive signals causing cornea formation or both signals. Fragments of larval epidermis or cornea developed from ectoderm that had undergone only one kind of inductive signals, or both kinds of signals, or none of them, were implanted into the vitreous chamber of host larvae. The regeneration potential and the lens-forming transformations of the implants were tested using an antisense probe for pax6 as an earlier marker of lens formation and a monoclonal antibody anti-lens as a definitive indicator of lens cell differentiation. Results demonstrated that the capacity of the larval outer cornea to regenerate a lens is the result of both early and late inductive signals and that either early inductive signals alone or late inductive signals alone can elicit this capacity
Myoblast Myogenic Differentiation but Not Fusion Process Is Inhibited via MyoD Tetraplex Interaction.
Full text linkThe presence of tetraplex structures in the promoter region of the myogenic differentiation 1 gene (MyoD1) was investigated with a specific tetraplex-binding porphyrin (TMPyP4), to test its influence on the expression of MyoD1 itself and downstream-regulated genes during myogenic differentiation. TMPyP4-exposed C2C12 myoblasts, blocking MyoD1 transcription, proliferated reaching confluence and fused forming elongated structures, resembling myotubes, devoid of myosin heavy chain 3 (MHC) expression. Besides lack of MHC, upon MyoD1 inhibition, other myogenic gene expressions were also affected in treated cells, while untreated control cell culture showed normal myotube formation expressing MyoD1, Myog, MRF4, Myf5, and MHC. Unexpectedly, the myomaker (Mymk) gene expression was not affected upon TMPyP4 exposure during C2C12 myogenic differentiation. At the genomic level, the bioinformatic comparison of putative tetraplex sites found that three tetraplexes in MyoD1 and Myog are highly conserved in mammals, while Mymk and MHC did not show any conserved tetraplexes in the analysed regions. Thus, here, we report for the first time that the inhibition of the MyoD1 promoter function, stabilizing the tetraplex region, affects downstream myogenic genes by blocking their expression, while leaving the expression of Mymk unaltered. These results reveal the existence of two distinct pathways: one leading to cell fusion and one guaranteeing correct myotube differentiation
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