Similarities and differences between induced organ regeneration in adults and early foetal regeneration

Yannas, Ioannis V.

doi:10.1098/rsif.2005.0062

Cited by 76 publications

(65 citation statements)

References 95 publications

(117 reference statements)

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“…It also entraps the hematoma and might prevent the contraction of the fibrinous blood clot, which is a necessary condition for the early phase of regeneration. (58) A structured fibrous tissue (light blue) around the scaffold bridging the defect is observed after 3 months. An onset of mineralized tissue (yellow) around the scaffold and in the endosteal cavity on the proximal end can also be seen, although the morphology is different from that found in an empty scaffold.…”

Section: Resultsmentioning

confidence: 99%

“…(60) It also matches Yannas' proposed mechanism of scaffold-guided organ regeneration. (58) He proposed that a scaffold can inhibit contraction, leading to wound closure, which is a necessary condition for the early phase of regeneration. Fibroblasts bind to the scaffold surface and deposit collagen fibers with an orientation parallel to the major cell axis.…”

Section: Discussionmentioning

confidence: 99%

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Porous scaffold architecture guides tissue formation

Cipitria

Lange

Schell

et al. 2012

Journal of Bone and Mineral Research

104

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Critical-sized bone defect regeneration is a remaining clinical concern. Numerous scaffold-based strategies are currently being investigated to enable in vivo bone defect healing. However, a deeper understanding of how a scaffold influences the tissue formation process and how this compares to endogenous bone formation or to regular fracture healing is missing. It is hypothesized that the porous scaffold architecture can serve as a guiding substrate to enable the formation of a structured fibrous network as a prerequirement for later bone formation. An ovine, tibial, 30-mm critical-sized defect is used as a model system to better understand the effect of the scaffold architecture on cell organization, fibrous tissue, and mineralized tissue formation mechanisms in vivo. Tissue regeneration patterns within two geometrically distinct macroscopic regions of a specific scaffold design, the scaffold wall and the endosteal cavity, are compared with tissue formation in an empty defect (negative control) and with cortical bone (positive control). Histology, backscattered electron imaging, scanning small-angle X-ray scattering, and nanoindentation are used to assess the morphology of fibrous and mineralized tissue, to measure the average mineral particle thickness and the degree of alignment, and to map the local elastic indentation modulus. The scaffold proves to function as a guiding substrate to the tissue formation process. It enables the arrangement of a structured fibrous tissue across the entire defect, which acts as a secondary supporting network for cells. Mineralization can then initiate along the fibrous network, resulting in bone ingrowth into a critical-sized defect, although not in complete bridging of the defect. The fibrous network morphology, which in turn is guided by the scaffold architecture, influences the microstructure of the newly formed bone. These results allow a deeper understanding of the mode of mineral tissue formation and the way this is influenced by the scaffold architecture. ß

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Porous scaffold architecture guides tissue formation

Cipitria

Lange

Schell

et al. 2012

Journal of Bone and Mineral Research

104

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“…Acellular dermal substitutes based on allogeneic, xenogeneic, or synthetic materials [12] are commercial alternatives. Nevertheless, it has been reported that contraction and scar formation cannot be completely prevented by an acellular dermal matrix unless the dermal and epidermal cells have been added [13]. In order to avoid those problems, many composite skin substitutes generated by tissue engineering were developed [12].…”

Section: Introductionmentioning

confidence: 99%

Dermal Papilla Cells Improve the Wound Healing Process and Generate Hair Bud-Like Structures in Grafted Skin Substitutes Using Hair Follicle Stem Cells

Leirós

Kusinsky

Drago³

et al. 2014

Stem Cells Translational Medicine

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Tissue-engineered skin represents a useful strategy for the treatment of deep skin injuries and might contribute to the understanding of skin regeneration. The use of dermal papilla cells (DPCs) as a dermal component in a permanent composite skin with human hair follicle stem cells (HFSCs) was evaluated by studying the tissue-engineered skin architecture, stem cell persistence, hair regeneration, and graft-take in nude mice. A porcine acellular dermal matrix was seeded with HFSCs alone and with HFSCs plus human DPCs or dermal fibroblasts (DFs). In vitro, the presence of DPCs induced a more regular and multilayered stratified epidermis with more basal p63-positive cells and invaginations. The DPC-containing constructs more accurately mimicked the skin architecture by properly stratifying the differentiating HFSCs and developing a well-ordered epithelia that contributed to more closely recapitulate an artificial human skin. This acellular dermal matrix previously repopulated in vitro with HFSCs and DFs or DPCs as the dermal component was grafted in nude mice. The presence of DPCs in the composite substitute not only favored early neovascularization, good assimilation and remodeling after grafting but also contributed to the neovascular network maturation, which might reduce the inflammation process, resulting in a better healing process, with less scarring and wound contraction. Interestingly, only DPC-containing constructs showed embryonic hair bud-like structures with cells of human origin, presence of precursor epithelial cells, and expression of a hair differentiation marker. Although preliminary, these findings have demonstrated the importance of the presence of DPCs for proper skin repair.

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“…Myofibroblast differentiation is regulated by at least TGF-b1, the presence of mechanical tension and an ECM component. A possible mechanism for contraction blocking by a scaffold is as below (Yannas 2005). Once having migrated inside the scaffold and become bound on the extensive surface of the highly porous scaffold, the long axes of myofibroblast lose their in-place orientation, becoming almost randomly oriented.…”

Section: Skinmentioning

confidence: 99%

Challenges in tissue engineering

Ikada

2006

J. R. Soc. Interface.

771

511

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Almost 30 years have passed since a term 'tissue engineering' was created to represent a new concept that focuses on regeneration of neotissues from cells with the support of biomaterials and growth factors. This interdisciplinary engineering has attracted much attention as a new therapeutic means that may overcome the drawbacks involved in the current artificial organs and organ transplantation that have been also aiming at replacing lost or severely damaged tissues or organs. However, the tissues regenerated by this tissue engineering and widely applied to patients are still very limited, including skin, bone, cartilage, capillary and periodontal tissues. What are the reasons for such slow advances in clinical applications of tissue engineering? This article gives the brief overview on the current tissue engineering, covering the fundamentals and applications. The fundamentals of tissue engineering involve the cell sources, scaffolds for cell expansion and differentiation and carriers for growth factors. Animal and human trials are the major part of the applications. Based on these results, some critical problems to be resolved for the advances of tissue engineering are addressed from the engineering point of view, emphasizing the close collaboration between medical doctors and biomaterials scientists.

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Similarities and differences between induced organ regeneration in adults and early foetal regeneration

Cited by 76 publications

References 95 publications

Porous scaffold architecture guides tissue formation

Porous scaffold architecture guides tissue formation

Dermal Papilla Cells Improve the Wound Healing Process and Generate Hair Bud-Like Structures in Grafted Skin Substitutes Using Hair Follicle Stem Cells

Challenges in tissue engineering

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