Notochord-derived hedgehog is essential for tail regeneration in Xenopus tadpole.

PubMed

Taniguchi, Yuka; Watanabe, Kenji; Mochii, Makoto

2014-06-18

Appendage regeneration in amphibians is regulated by the combinatorial actions of signaling molecules. The requirement of molecules secreted from specific tissues is reflected by the observation that the whole process of regeneration can be inhibited if a certain tissue is removed from the amputated stump. Interestingly, urodeles and anurans show different tissue dependencies during tail regeneration. The spinal cord is essential for tail regeneration in urodele but not in anuran larva, whereas the notochord but not the spinal cord is essential for tail regeneration in anuran tadpoles. Sonic hedgehog is one of the signaling molecules responsible for such phenomenon in axolotl, as hedgehog signaling is essential for overall tail regeneration and sonic hedgehog is exclusively expressed in the spinal cord. In order to know whether hedgehog signaling is involved in the molecular mechanism underlying the inconsistent tissue dependency for tail regeneration between anurans and urodeles, we investigated expression of hedgehog signal-related genes in the regenerating tail of Xenopus tadpole and examined the effect of the hedgehog signal inhibitor, cyclopamine, on the tail regeneration. In Xenopus, sonic hedgehog is expressed exclusively in the notochord but not in the spinal cord of the regenerate. Overall regeneration was severely impaired in cyclopamine-treated tadpoles. Notochord maturation in the regenerate, including cell alignment and vacuolation, and myofiber formation were inhibited. Proliferation of spinal cord cells in the neural ampulla and of mesenchymal cells was also impaired. As in the axolotl, hedgehog signaling is required for multiple steps in tail regeneration in the Xenopus tadpole, although the location of the Shh source is quite different between the two species. This difference in Shh localization is the likely basis for the differing tissue requirement for tail regeneration between urodeles and anurans.

Notochord-derived hedgehog is essential for tail regeneration in Xenopus tadpole

PubMed Central

2014-01-01

Background Appendage regeneration in amphibians is regulated by the combinatorial actions of signaling molecules. The requirement of molecules secreted from specific tissues is reflected by the observation that the whole process of regeneration can be inhibited if a certain tissue is removed from the amputated stump. Interestingly, urodeles and anurans show different tissue dependencies during tail regeneration. The spinal cord is essential for tail regeneration in urodele but not in anuran larva, whereas the notochord but not the spinal cord is essential for tail regeneration in anuran tadpoles. Sonic hedgehog is one of the signaling molecules responsible for such phenomenon in axolotl, as hedgehog signaling is essential for overall tail regeneration and sonic hedgehog is exclusively expressed in the spinal cord. In order to know whether hedgehog signaling is involved in the molecular mechanism underlying the inconsistent tissue dependency for tail regeneration between anurans and urodeles, we investigated expression of hedgehog signal-related genes in the regenerating tail of Xenopus tadpole and examined the effect of the hedgehog signal inhibitor, cyclopamine, on the tail regeneration. Results In Xenopus, sonic hedgehog is expressed exclusively in the notochord but not in the spinal cord of the regenerate. Overall regeneration was severely impaired in cyclopamine-treated tadpoles. Notochord maturation in the regenerate, including cell alignment and vacuolation, and myofiber formation were inhibited. Proliferation of spinal cord cells in the neural ampulla and of mesenchymal cells was also impaired. Conclusion As in the axolotl, hedgehog signaling is required for multiple steps in tail regeneration in the Xenopus tadpole, although the location of the Shh source is quite different between the two species. This difference in Shh localization is the likely basis for the differing tissue requirement for tail regeneration between urodeles and anurans. PMID:24941877

Group C. Initiator paper. Periodontal regeneration--fact or fiction?

PubMed

Bartold, P M

2015-01-01

Numerous techniques have been tried and tested to regenerate tissues lost to periodontal disease. While there has been some success to date, more work is required to move this to a reliable and clinically predictable procedure. Much of the future success for such treatments will rely largely on our understanding of the biology of both developmental and regenerative processes. Nonetheless, despite the noble goal of periodontal regeneration, the relevance of re-creation of a connective tissue attachment has been questioned. Since formation of a long junctional epithelial attachment to the tooth following a variety of periodontal treatment procedures has been shown to be no more susceptible to further breakdown than a non-diseased site, the question arises as to what purpose do we seek the ultimate outcome of periodontal regeneration? The answer lies in the "fact and fiction" of periodontal regeneration. There is no doubt that the regenerative procedures that have been developed can be shown to be biologically successful at the histological level. Furthermore, the results of periodontal regeneration (particularly guided tissue regeneration) have been stable over the long term (at least up to 10 years). However, the techniques currently under use which show the greatest promise (guided tissue regeneration and growth factors) are still clinically unpredictable because of their highly technique-sensitive nature. In addition, whether the slight clinical improvements offered by these procedures over routine open flap debridement procedures are of cost or patient benefit with regards to improved periodontal health and retention of teeth remains to be established. The next phase in regenerative technologies will undoubtedly involve a deeper understanding of the molecular signaling (both intra- and extra-cellular) and cellular differentiation processes involved in the regenerative processes. So in answer to the question of whether periodontal regeneration is fact or fiction, the answer clearly is that it is both. However, with more work it will become established fact with little fiction and the desired clinical endpoint of predictable regeneration of the periodontal tissues damaged by inflammation to their original form and function will be achieved.

Cap-n-Collar Promotes Tissue Regeneration by Regulating ROS and JNK Signaling in the Drosophila melanogaster Wing Imaginal Disc.

PubMed

Brock, Amanda R; Seto, Mabel; Smith-Bolton, Rachel K

2017-07-01

Regeneration is a complex process that requires an organism to recognize and repair tissue damage, as well as grow and pattern new tissue. Here, we describe a genetic screen to identify novel regulators of regeneration. We ablated the Drosophila melanogaster larval wing primordium by inducing apoptosis in a spatially and temporally controlled manner and allowed the tissue to regenerate and repattern. To identify genes that regulate regeneration, we carried out a dominant-modifier screen by assessing the amount and quality of regeneration in adult wings heterozygous for isogenic deficiencies. We have identified 31 regions on the right arm of the third chromosome that modify the regenerative response. Interestingly, we observed several distinct phenotypes: mutants that regenerated poorly, mutants that regenerated faster or better than wild-type, and mutants that regenerated imperfectly and had patterning defects. We mapped one deficiency region to cap-n-collar ( cnc ), the Drosophila Nrf2 ortholog, which is required for regeneration. Cnc regulates reactive oxygen species levels in the regenerating epithelium, and affects c-Jun N-terminal protein kinase (JNK) signaling, growth, debris localization, and pupariation timing. Here, we present the results of our screen and propose a model wherein Cnc regulates regeneration by maintaining an optimal level of reactive oxygen species to promote JNK signaling. Copyright © 2017 by the Genetics Society of America.

Tissue Regeneration and Biomineralization in Sea Urchins: Role of Notch Signaling and Presence of Stem Cell Markers

PubMed Central

Reinardy, Helena C.; Emerson, Chloe E.; Manley, Jason M.; Bodnar, Andrea G.

2015-01-01

Echinoderms represent a phylum with exceptional regenerative capabilities that can reconstruct both external appendages and internal organs. Mechanistic understanding of the cellular pathways involved in regeneration in these animals has been hampered by the limited genomic tools and limited ability to manipulate regenerative processes. We present a functional assay to investigate mechanisms of tissue regeneration and biomineralization by measuring the regrowth of amputated tube feet (sensory and motor appendages) and spines in the sea urchin, Lytechinus variegatus. The ability to manipulate regeneration was demonstrated by concentration-dependent inhibition of regrowth of spines and tube feet by treatment with the mitotic inhibitor, vincristine. Treatment with the gamma-secretase inhibitor DAPT resulted in a concentration-dependent inhibition of regrowth, indicating that both tube feet and spine regeneration require functional Notch signaling. Stem cell markers (Piwi and Vasa) were expressed in tube feet and spine tissue, and Vasa-positive cells were localized throughout the epidermis of tube feet by immunohistochemistry, suggesting the existence of multipotent progenitor cells in these highly regenerative appendages. The presence of Vasa protein in other somatic tissues (e.g. esophagus, radial nerve, and a sub-population of coelomocytes) suggests that multipotent cells are present throughout adult sea urchins and may contribute to normal homeostasis in addition to regeneration. Mechanistic insight into the cellular pathways governing the tremendous regenerative capacity of echinoderms may reveal processes that can be modulated for regenerative therapies, shed light on the evolution of regeneration, and enable the ability to predict how these processes will respond to changing environmental conditions. PMID:26267358

Transient inflammatory response mediated by interleukin-1β is required for proper regeneration in zebrafish fin fold

PubMed Central

Hasegawa, Tomoya; Hall, Christopher J; Crosier, Philip S; Abe, Gembu; Kawakami, Koichi; Kudo, Akira; Kawakami, Atsushi

2017-01-01

Cellular responses to injury are crucial for complete tissue regeneration, but their underlying processes remain incompletely elucidated. We have previously reported that myeloid-defective zebrafish mutants display apoptosis of regenerative cells during fin fold regeneration. Here, we found that the apoptosis phenotype is induced by prolonged expression of interleukin 1 beta (il1b). Myeloid cells are considered to be the principal source of Il1b, but we show that epithelial cells express il1b in response to tissue injury and initiate the inflammatory response, and that its resolution by macrophages is necessary for survival of regenerative cells. We further show that Il1b plays an essential role in normal fin fold regeneration by regulating expression of regeneration-induced genes. Our study reveals that proper levels of Il1b signaling and tissue inflammation, which are tuned by macrophages, play a crucial role in tissue regeneration. DOI: http://dx.doi.org/10.7554/eLife.22716.001 PMID:28229859

Promoting tissue regeneration by modulating the immune system.

PubMed

Julier, Ziad; Park, Anthony J; Briquez, Priscilla S; Martino, Mikaël M

2017-04-15

The immune system plays a central role in tissue repair and regeneration. Indeed, the immune response to tissue injury is crucial in determining the speed and the outcome of the healing process, including the extent of scarring and the restoration of organ function. Therefore, controlling immune components via biomaterials and drug delivery systems is becoming an attractive approach in regenerative medicine, since therapies based on stem cells and growth factors have not yet proven to be broadly effective in the clinic. To integrate the immune system into regenerative strategies, one of the first challenges is to understand the precise functions of the different immune components during the tissue healing process. While remarkable progress has been made, the immune mechanisms involved are still elusive, and there is indication for both negative and positive roles depending on the tissue type or organ and life stage. It is well recognized that the innate immune response comprising danger signals, neutrophils and macrophages modulates tissue healing. In addition, it is becoming evident that the adaptive immune response, in particular T cell subset activities, plays a critical role. In this review, we first present an overview of the basic immune mechanisms involved in tissue repair and regeneration. Then, we highlight various approaches based on biomaterials and drug delivery systems that aim at modulating these mechanisms to limit fibrosis and promote regeneration. We propose that the next generation of regenerative therapies may evolve from typical biomaterial-, stem cell-, or growth factor-centric approaches to an immune-centric approach. Most regenerative strategies have not yet proven to be safe or reasonably efficient in the clinic. In addition to stem cells and growth factors, the immune system plays a crucial role in the tissue healing process. Here, we propose that controlling the immune-mediated mechanisms of tissue repair and regeneration may support existing regenerative strategies or could be an alternative to using stem cells and growth factors. The first part of this review we highlight key immune mechanisms involved in the tissue healing process and marks them as potential target for designing regenerative strategies. In the second part, we discuss various approaches using biomaterials and drug delivery systems that aim at modulating the components of the immune system to promote tissue regeneration. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Fibroblast growth factors: key players in regeneration and tissue repair.

PubMed

Maddaluno, Luigi; Urwyler, Corinne; Werner, Sabine

2017-11-15

Tissue injury initiates a complex repair process, which in some organisms can lead to the complete regeneration of a tissue. In mammals, however, the repair of most organs is imperfect and results in scar formation. Both regeneration and repair are orchestrated by a highly coordinated interplay of different growth factors and cytokines. Among the key players are the fibroblast growth factors (FGFs), which control the migration, proliferation, differentiation and survival of different cell types. In addition, FGFs influence the expression of other factors involved in the regenerative response. Here, we summarize current knowledge on the roles of endogenous FGFs in regeneration and repair in different organisms and in different tissues and organs. Gaining a better understanding of these FGF activities is important for appropriate modulation of FGF signaling after injury to prevent impaired healing and to promote organ regeneration in humans. © 2017. Published by The Company of Biologists Ltd.

Periodontal tissue engineering strategies based on nonoral stem cells.

PubMed

Requicha, João Filipe; Viegas, Carlos Alberto; Muñoz, Fernando; Reis, Rui Luís; Gomes, Manuela Estima

2014-01-01

Periodontal disease is an inflammatory disease which constitutes an important health problem in humans due to its enormous prevalence and life threatening implications on systemic health. Routine standard periodontal treatments include gingival flaps, root planning, application of growth/differentiation factors or filler materials and guided tissue regeneration. However, these treatments have come short on achieving regeneration ad integrum of the periodontium, mainly due to the presence of tissues from different embryonic origins and their complex interactions along the regenerative process. Tissue engineering (TE) aims to regenerate damaged tissue by providing the repair site with a suitable scaffold seeded with sufficient undifferentiated cells and, thus, constitutes a valuable alternative to current therapies for the treatment of periodontal defects. Stem cells from oral and dental origin are known to have potential to regenerate these tissues. Nevertheless, harvesting cells from these sites implies a significant local tissue morbidity and low cell yield, as compared to other anatomical sources of adult multipotent stem cells. This manuscript reviews studies describing the use of non-oral stem cells in tissue engineering strategies, highlighting the importance and potential of these alternative stem cells sources in the development of advanced therapies for periodontal regeneration. Copyright © 2013 Wiley Periodicals, Inc.

Cytoskeletal Regulation of Dermal Regeneration

PubMed Central

Strudwick, Xanthe L.; Cowin, Allison J.

2012-01-01

Wound healing results in the repair of injured tissues however fibrosis and scar formation are, more often than not the unfortunate consequence of this process. The ability of lower order vertebrates and invertebrates to regenerate limbs and tissues has been all but lost in mammals; however, there are some instances where glimpses of mammalian regenerative capacity do exist. Here we describe the unlocked potential that exists in mammals that may help us understand the process of regeneration post-injury and highlight the potential role of the actin cytoskeleton in this process. The precise function and regulation of the cytoskeleton is critical to the success of the healing process and its manipulation may therefore facilitate regenerative healing. The gelsolin family of actin remodelling proteins in particular has been shown to have important functions in wound healing and family member Flightless I (Flii) is involved in both regeneration and repair. Understanding the interactions between different cytoskeletal proteins and their dynamic control of processes including cellular adhesion, contraction and motility may assist the development of therapeutics that will stimulate regeneration rather than repair. PMID:24710556

Soft tissue wound healing at teeth, dental implants and the edentulous ridge when using barrier membranes, growth and differentiation factors and soft tissue substitutes.

PubMed

Vignoletti, Fabio; Nunez, Javier; Sanz, Mariano

2014-04-01

To review the biological processes of wound healing following periodontal and periimplant plastic surgery when different technologies are used in a) the coverage of root and implant dehiscences, b) the augmentation of keratinized tissue (KT) and c) the augmentation of soft tissue volume. An electronic search from The National Library of Medicine (MEDLINE-PubMed) was performed: English articles with research focus in oral soft tissue regeneration, providing histological outcomes, either from animal experimental studies or human biopsy material were included. Barrier membranes, enamel matrix derivatives, growth factors, allogeneic and xenogeneic soft tissue substitutes have been used in soft tissue regeneration demonstrating different degrees of regeneration. In root coverage, these technologies were able to improve new attachment, although none has shown complete regeneration. In KT augmentation, tissue-engineered allogenic products and xenogeneic collagen matrixes demonstrated integration within the host connective tissue and promotion of keratinization. In soft tissue augmentation and peri-implant plastic surgery there are no histological data currently available. Soft tissue substitutes, growth differentiation factors demonstrated promising histological results in terms of soft tissue regeneration and keratinization, whereas there is a need for further studies to prove their added value in soft tissue augmentation. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Periodontal regeneration in gingival recession defects.

PubMed

Trombelli, L

1999-02-01

Surgical treatment of gingival recession defects aims at obtaining soft tissue coverage of exposed root surfaces and/or augmentation of gingival tissue dimensions. A variety of protocols have been developed to manage these clinical problems. Since one goal of periodontal therapy is the regeneration of the lost attachment apparatus of the tooth, full restoration of defect should be accomplished following mucogingival procedures. This implies regeneration of all periodontal structures, including formation of new cementum with inserting connective tissue fibers, alveolar bone regeneration and recreation of a functional and aesthetic morphology of the mucogingival complex. Animal and human histological studies have shown that healing at gingiva-root interface following pedicle flaps or free soft tissue grafts generally includes a long junctional epithelium with varying amounts of a new connective tissue attachment in the most apical aspect of the covered root surface. Limited bone regeneration has been observed. Adjunctive use of root conditioning agents and cell excluding, wound-stabilizing devices may amplify regenerative outcomes. Changes in the amount of keratinized tissue, which can significantly affect the aesthetic outcome of treatment, have been shown to depend on the interactions among various tissues involved in the healing process and the selected surgical procedure.

Regeneration of bone and periodontal ligament induced by recombinant amelogenin after periodontitis.

PubMed

Haze, Amir; Taylor, Angela L; Haegewald, Stefan; Leiser, Yoav; Shay, Boaz; Rosenfeld, Eli; Gruenbaum-Cohen, Yael; Dafni, Leah; Zimmermann, Bernd; Heikinheimo, Kristiina; Gibson, Carolyn W; Fisher, Larry W; Young, Marian F; Blumenfeld, Anat; Bernimoulin, Jean P; Deutsch, Dan

2009-06-01

Regeneration of mineralized tissues affected by chronic diseases comprises a major scientific and clinical challenge. Periodontitis, one such prevalent disease, involves destruction of the tooth-supporting tissues, alveolar bone, periodontal-ligament and cementum, often leading to tooth loss. In 1997, it became clear that, in addition to their function in enamel formation, the hydrophobic ectodermal enamel matrix proteins (EMPs) play a role in the regeneration of these periodontal tissues. The epithelial EMPs are a heterogeneous mixture of polypeptides encoded by several genes. It was not clear, however, which of these many EMPs induces the regeneration and what mechanisms are involved. Here we show that a single recombinant human amelogenin protein (rHAM(+)), induced in vivo regeneration of all tooth-supporting tissues after creation of experimental periodontitis in a dog model. To further understand the regeneration process, amelogenin expression was detected in normal and regenerating cells of the alveolar bone (osteocytes, osteoblasts and osteoclasts), periodontal ligament, cementum and in bone marrow stromal cells. Amelogenin expression was highest in areas of high bone turnover and activity. Further studies showed that during the first 2 weeks after application, rHAM(+) induced, directly or indirectly, significant recruitment of mesenchymal progenitor cells, which later differentiated to form the regenerated periodontal tissues. The ability of a single protein to bring about regeneration of all periodontal tissues, in the correct spatio-temporal order, through recruitment of mesenchymal progenitor cells, could pave the way for development of new therapeutic devices for treatment of periodontal, bone and ligament diseases based on rHAM(+).

Tail regeneration and other phenomena of wound healing and tissue restoration in lizards.

PubMed

Jacyniak, Kathy; McDonald, Rebecca P; Vickaryous, Matthew K

2017-08-15

Wound healing is a fundamental evolutionary adaptation with two possible outcomes: scar formation or reparative regeneration. Scars participate in re-forming the barrier with the external environment and restoring homeostasis to injured tissues, but are well understood to represent dysfunctional replacements. In contrast, reparative regeneration is a tissue-specific program that near-perfectly replicates that which was lost or damaged. Although regeneration is best known from salamanders (including newts and axolotls) and zebrafish, it is unexpectedly widespread among vertebrates. For example, mice and humans can replace their digit tips, while many lizards can spontaneously regenerate almost their entire tail. Whereas the phenomenon of lizard tail regeneration has long been recognized, many details of this process remain poorly understood. All of this is beginning to change. This Review provides a comparative perspective on mechanisms of wound healing and regeneration, with a focus on lizards as an emerging model. Not only are lizards able to regrow cartilage and the spinal cord following tail loss, some species can also regenerate tissues after full-thickness skin wounds to the body, transections of the optic nerve and even lesions to parts of the brain. Current investigations are advancing our understanding of the biological requirements for successful tissue and organ repair, with obvious implications for biomedical sciences and regenerative medicine. © 2017. Published by The Company of Biologists Ltd.

Vascular Regeneration in a Basal Chordate Is Due to the Presence of Immobile, Bi-Functional Cells

PubMed Central

Braden, Brian P.; Taketa, Daryl A.; Pierce, James D.; Kassmer, Susannah; Lewis, Daniel D.; De Tomaso, Anthony W.

2014-01-01

The source of tissue turnover during homeostasis or following injury is usually due to proliferation of a small number of resident, lineage-restricted stem cells that have the ability to amplify and differentiate into mature cell types. We are studying vascular regeneration in a chordate model organism, Botryllus schlosseri, and have previously found that following surgical ablation of the extracorporeal vasculature, new tissue will regenerate in a VEGF-dependent process within 48 hrs. Here we use a novel vascular cell lineage tracing methodology to assess regeneration in parabiosed individuals and demonstrate that the source of regenerated vasculature is due to the proliferation of pre-existing vascular resident cells and not a mobile progenitor. We also show that these cells are bi-potential, and can reversibly adopt two fates, that of the newly forming vessels or the differentiated vascular tissue at the terminus of the vasculature, known as ampullae. In addition, we show that pre-existing vascular resident cells differentially express progenitor and differentiated cell markers including the Botryllus homologs of CD133, VEGFR-2, and Cadherin during the regenerative process. PMID:24736432

Ion channel signaling influences cellular proliferation and phagocyte activity during axolotl tail regeneration.

PubMed

Franklin, Brandon M; Voss, S Randal; Osborn, Jeffrey L

2017-08-01

Little is known about the potential for ion channels to regulate cellular behaviors during tissue regeneration. Here, we utilized an amphibian tail regeneration assay coupled with a chemical genetic screen to identify ion channel antagonists that altered critical cellular processes during regeneration. Inhibition of multiple ion channels either partially (anoctamin1/Tmem16a, anoctamin2/Tmem16b, K V 2.1, K V 2.2, L-type Ca V channels and H/K ATPases) or completely (GlyR, GABA A R, K V 1.5 and SERCA pumps) inhibited tail regeneration. Partial inhibition of tail regeneration by blocking the calcium activated chloride channels, anoctamin1&2, was associated with a reduction of cellular proliferation in tail muscle and mesenchymal regions. Inhibition of anoctamin 1/2 also altered the post-amputation transcriptional response of p44/42 MAPK signaling pathway genes, including decreased expression of erk1/erk2. We also found that complete inhibition via voltage gated K + channel blockade was associated with diminished phagocyte recruitment to the amputation site. The identification of H + pumps as required for axolotl tail regeneration supports findings in Xenopus and Planaria models, and more generally, the conservation of ion channels as regulators of tissue regeneration. This study provides a preliminary framework for an in-depth investigation of the mechanistic role of ion channels and their potential involvement in regulating cellular proliferation and other processes essential to wound healing, appendage regeneration, and tissue repair. Copyright © 2017 Elsevier B.V. All rights reserved.

Nanoscale Surface Modifications of Medical Implants for Cartilage Tissue Repair and Regeneration

PubMed Central

Griffin, MF; Szarko, M; Seifailan, A; Butler, PE

2016-01-01

Background: Natural cartilage regeneration is limited after trauma or degenerative processes. Due to the clinical challenge of reconstruction of articular cartilage, research into developing biomaterials to support cartilage regeneration have evolved. The structural architecture of composition of the cartilage extracellular matrix (ECM) is vital in guiding cell adhesion, migration and formation of cartilage. Current technologies have tried to mimic the cell’s nanoscale microenvironment to improve implants to improve cartilage tissue repair. Methods: This review evaluates nanoscale techniques used to modify the implant surface for cartilage regeneration. Results: The surface of biomaterial is a vital parameter to guide cell adhesion and consequently allow for the formation of ECM and allow for tissue repair. By providing nanosized cues on the surface in the form of a nanotopography or nanosized molecules, allows for better control of cell behaviour and regeneration of cartilage. Chemical, physical and lithography techniques have all been explored for modifying the nanoscale surface of implants to promote chondrocyte adhesion and ECM formation. Conclusion: Future studies are needed to further establish the optimal nanoscale modification of implants for cartilage tissue regeneration. PMID:28217208

Tissue regeneration with photobiomodulation

NASA Astrophysics Data System (ADS)

Tang, Elieza G.; Arany, Praveen R.

2013-03-01

Low level light therapy (LLLT) has been widely reported to reduce pain and inflammation and enhance wound healing and tissue regeneration in various settings. LLLT has been noted to have both stimulatory and inhibitory biological effects and these effects have been termed Photobiomodulation (PBM). Several elegant studies have shown the key role of Cytochrome C oxidase and ROS in initiating this process. The downstream biological responses remain to be clearly elucidated. Our work has demonstrated activation of an endogenous latent growth factor complex, TGF-β1, as one of the major biological events in PBM. TGF-β1 has critical roles in various biological processes especially in inflammation, immune responses, wound healing and stem cell biology. This paper overviews some of the studies demonstrating the efficacy of PBM in promoting tissue regeneration.

Common cellular events occur during wound healing and organ regeneration in the sea cucumber Holothuria glaberrima.

PubMed

San Miguel-Ruiz, José E; García-Arrarás, José E

2007-10-18

All animals possess some type of tissue repair mechanism. In some species, the capacity to repair tissues is limited to the healing of wounds. Other species, such as echinoderms, posses a striking repair capability that can include the replacement of entire organs. It has been reported that some mechanisms, namely extracellular matrix remodeling, appear to occur in most repair processes. However, it remains unclear to what extent the process of organ regeneration, particularly in animals where loss and regeneration of complex structures is a programmed natural event, is similar to wound healing. We have now used the sea cucumber Holothuria glaberrima to address this question. Animals were lesioned by making a 3-5 mm transverse incision between one of the longitudinal muscle pairs along the bodywall. Lesioned tissues included muscle, nerve, water canal and dermis. Animals were allowed to heal for up to four weeks (2, 6, 12, 20, and 28 days post-injury) before sacrificed. Tissues were sectioned in a cryostat and changes in cellular and tissue elements during repair were evaluated using classical dyes, immmuohistochemistry and phalloidin labeling. In addition, the temporal and spatial distribution of cell proliferation in the animals was assayed using BrdU incorporation. We found that cellular events associated with wound healing in H. glaberrima correspond to those previously shown to occur during intestinal regeneration. These include: (1) an increase in the number of spherule-containing cells, (2) remodeling of the extracellular matrix, (3) formation of spindle-like structures that signal dedifferentiation of muscle cells in the area flanking the lesion site and (4) intense cellular division occurring mainly in the coelomic epithelium after the first week of regeneration. Our data indicate that H. glaberrima employs analogous cellular mechanisms during wound healing and organ regeneration. Thus, it is possible that regenerative limitations in some organisms are due either to the absence of particular mechanisms associated with repair or the inability of activating the repair process in some tissues or stages.

Paracrine control of tissue regeneration and cell proliferation by Caspase-3

PubMed Central

Boland, K; Flanagan, L; Prehn, J HM

2013-01-01

Executioner caspases such as Caspase-3 and Caspase-7 have long been recognised as the key proteases involved in cell demolition during apoptosis. Caspase activation also modulates signal transduction inside cells, through activation or inactivation of kinases, phosphatases and other signalling molecules. Interestingly, a series of recent studies have demonstrated that caspase activation may also influence signal transduction and gene expression changes in neighbouring cells that themselves did not activate caspases. This review describes the physiological relevance of paracrine Caspase-3 signalling for developmental processes, tissue homeostasis and tissue regeneration, and discusses the role of soluble factors and microparticles in mediating these paracrine activities. While non-cell autonomous control of tissue regeneration by Caspase-3 may represent an important process for maintaining tissue homeostasis, it may limit the efficiency of current cancer therapy by promoting cell proliferation in those cancer cells resistant to radio- or chemotherapy. We discuss recent evidence in support of such a role for Caspase-3, and discuss its therapeutic implication. PMID:23846227

Xiphoid Process-Derived Chondrocytes: A Novel Cell Source for Elastic Cartilage Regeneration

PubMed Central

Nam, Seungwoo; Cho, Wheemoon; Cho, Hyunji; Lee, Jungsun

2014-01-01

Reconstruction of elastic cartilage requires a source of chondrocytes that display a reliable differentiation tendency. Predetermined tissue progenitor cells are ideal candidates for meeting this need; however, it is difficult to obtain donor elastic cartilage tissue because most elastic cartilage serves important functions or forms external structures, making these tissues indispensable. We found vestigial cartilage tissue in xiphoid processes and characterized it as hyaline cartilage in the proximal region and elastic cartilage in the distal region. Xiphoid process-derived chondrocytes (XCs) showed superb in vitro expansion ability based on colony-forming unit fibroblast assays, cell yield, and cumulative cell growth. On induction of differentiation into mesenchymal lineages, XCs showed a strong tendency toward chondrogenic differentiation. An examination of the tissue-specific regeneration capacity of XCs in a subcutaneous-transplantation model and autologous chondrocyte implantation model confirmed reliable regeneration of elastic cartilage regardless of the implantation environment. On the basis of these observations, we conclude that xiphoid process cartilage, the only elastic cartilage tissue source that can be obtained without destroying external shape or function, is a source of elastic chondrocytes that show superb in vitro expansion and reliable differentiation capacity. These findings indicate that XCs could be a valuable cell source for reconstruction of elastic cartilage. PMID:25205841

Delivery of growth factors for tissue regeneration and wound healing.

PubMed

Koria, Piyush

2012-06-01

Growth factors are soluble secreted proteins capable of affecting a variety of cellular processes important for tissue regeneration. Consequently, the self-healing capacity of patients can be augmented by artificially enhancing one or more processes important for healing through the application of growth factors. However, their application in clinics remains limited due to lack of robust delivery systems and biomaterial carriers. Interestingly, all clinically approved therapies involving growth factors utilize some sort of a biomaterial carrier for growth factor delivery. This suggests that biomaterial delivery systems are extremely important for successful usage of growth factors in regenerative medicine. This review outlines the role of growth factors in tissue regeneration, and their application in both pre-clinical animal models of regeneration and clinical trials is discussed. Additionally, current status of biomaterial substrates and sophisticated delivery systems such as nanoparticles for delivery of exogenous growth factors and peptides in humans are reviewed. Finally, issues and possible future research directions for growth factor therapy in regenerative medicine are discussed.

Stem cell-based growth, regeneration, and remodeling of the planarian intestine

PubMed Central

Forsthoefel, David J.; Park, Amanda E.; Newmark, Phillip A.

2011-01-01

Although some animals are capable of regenerating organs, the mechanisms by which this is achieved are poorly understood. In planarians, pluripotent somatic stem cells called neoblasts supply new cells for growth, replenish tissues in response to cellular turnover, and regenerate tissues after injury. For most tissues and organs, however, the spatiotemporal dynamics of stem cell differentiation and the fate of tissue that existed prior to injury have not been characterized systematically. Utilizing in vivo imaging and bromodeoxyuridine pulse-chase experiments, we have analyzed growth and regeneration of the planarian intestine, the organ responsible for digestion and nutrient distribution. During growth, we observe that new gut branches are added along the entire anteroposterior axis. We find that new enterocytes differentiate throughout the intestine rather than in specific growth zones, suggesting that branching morphogenesis is achieved primarily by remodeling of differentiated intestinal tissues. During regeneration, we also demonstrate a previously unappreciated degree of intestinal remodeling, in which pre-existing posterior gut tissue contributes extensively to the newly formed anterior gut, and vice versa. By contrast to growing animals, differentiation of new intestinal cells occurs at preferential locations, including within newly generated tissue (the blastema), and along pre-existing intestinal branches undergoing remodeling. Our results indicate that growth and regeneration of the planarian intestine are achieved by coordinated differentiation of stem cells and the remodeling of pre-existing tissues. Elucidation of the mechanisms by which these processes are integrated will be critical for understanding organogenesis in a post-embryonic context. PMID:21664348

MOR23 promotes muscle regeneration and regulates cell adhesion and migration

PubMed Central

Griffin, Christine A.; Kafadar, Kimberly A.; Pavlath, Grace K.

2009-01-01

Summary Odorant receptors (ORs) in the olfactory epithelium bind to volatile small molecules leading to the perception of smell. ORs are expressed in many tissues but their functions are largely unknown. We show multiple ORs display distinct mRNA expression patterns during myogenesis in vitro and muscle regeneration in vivo. Mouse OR23 (MOR23) expression is induced during muscle regeneration when muscle cells are extensively fusing and plays a key role in regulating migration and adhesion of muscle cells in vitro, two processes common during tissue repair. A soluble ligand for MOR23 is secreted by muscle cells in vitro and muscle tissue in vivo. MOR23 is necessary for proper skeletal muscle regeneration as loss of MOR23 leads to increased myofiber branching, commonly associated with muscular dystrophy. Together these data identify a functional role for an OR outside of the nose and suggest a larger role for ORs during tissue repair. PMID:19922870

First Insights into Human Fingertip Regeneration by Echo-Doppler Imaging and Wound Microenvironment Assessment.

PubMed

Jafari, Paris; Muller, Camillo; Grognuz, Anthony; Applegate, Lee Ann; Raffoul, Wassim; di Summa, Pietro G; Durand, Sébastien

2017-05-13

Fingertip response to trauma represents a fascinating example of tissue regeneration. Regeneration derives from proliferative mesenchymal cells (blastema) that subsequently differentiate into soft and skeletal tissues. Clinically, conservative treatment of the amputated fingertip under occlusive dressing can shift the response to tissue loss from a wound repair process towards regeneration. When analyzing by Immunoassay the wound exudate from occlusive dressings, the concentrations of brain-derived neurotrophic factor (BDNF) and leukemia inhibitory factor (LIF) were higher in fingertip exudates than in burn wounds (used as controls for wound repair versus regeneration). Vascular endothelial growth factor A (VEGF-A) and platelet-derived growth factor (PDGF) were highly expressed in both samples in comparable levels. In our study, pro-inflammatory cytokines were relatively higher expressed in regenerative fingertips than in the burn wound exudates while chemokines were present in lower levels. Functional, vascular and mechanical properties of the regenerated fingertips were analyzed three months after trauma and the data were compared to the corresponding fingertip on the collateral uninjured side. While sensory recovery and morphology (pulp thickness and texture) were similar to uninjured sides, mechanical parameters (elasticity, vascularization) were increased in the regenerated fingertips. Further studies should be done to clarify the importance of inflammatory cells, immunity and growth factors in determining the outcome of the regenerative process and its influence on the clinical outcome.

First Insights into Human Fingertip Regeneration by Echo-Doppler Imaging and Wound Microenvironment Assessment

PubMed Central

Jafari, Paris; Muller, Camillo; Grognuz, Anthony; Applegate, Lee Ann; Raffoul, Wassim; di Summa, Pietro G.; Durand, Sébastien

2017-01-01

Fingertip response to trauma represents a fascinating example of tissue regeneration. Regeneration derives from proliferative mesenchymal cells (blastema) that subsequently differentiate into soft and skeletal tissues. Clinically, conservative treatment of the amputated fingertip under occlusive dressing can shift the response to tissue loss from a wound repair process towards regeneration. When analyzing by Immunoassay the wound exudate from occlusive dressings, the concentrations of brain-derived neurotrophic factor (BDNF) and leukemia inhibitory factor (LIF) were higher in fingertip exudates than in burn wounds (used as controls for wound repair versus regeneration). Vascular endothelial growth factor A (VEGF-A) and platelet-derived growth factor (PDGF) were highly expressed in both samples in comparable levels. In our study, pro-inflammatory cytokines were relatively higher expressed in regenerative fingertips than in the burn wound exudates while chemokines were present in lower levels. Functional, vascular and mechanical properties of the regenerated fingertips were analyzed three months after trauma and the data were compared to the corresponding fingertip on the collateral uninjured side. While sensory recovery and morphology (pulp thickness and texture) were similar to uninjured sides, mechanical parameters (elasticity, vascularization) were increased in the regenerated fingertips. Further studies should be done to clarify the importance of inflammatory cells, immunity and growth factors in determining the outcome of the regenerative process and its influence on the clinical outcome. PMID:28505080

Integration of zebrafish fin regeneration genes with expression data of human tumors in silico uncovers potential novel melanoma markers.

PubMed

Hagedorn, Martin; Siegfried, Géraldine; Hooks, Katarzyna B; Khatib, Abdel-Majid

2016-11-01

Tissue regeneration requires expression of a large, unknown number of genes to initiate and maintain cellular processes such as proliferation, extracellular matrix synthesis, differentiation and migration. A unique model to simulate this process in a controlled manner is the re-growth of the caudal fin of zebrafish after amputation. Within this tissue stem cells differentiate into fibroblasts, epithelial and endothelial cells as well as melanocytes. Many genes implicated in the regeneration process are deregulated in cancer. We therefore undertook a systematic gene expression study to identify genes upregulated during the re-growth of caudal fin tissue. By applying a high stringency cut-off value of 4-fold change, we identified 54 annotated genes significantly overexpressed in regenerating blastema. Further bioinformatics data mining studies showed that 22 out of the 54 regeneration genes where overexpressed in melanoma compared to normal skin or other cancers. Whereas the role of TNC (tenascin C) and FN1 (fibronectin 1) in melanoma development is well documented, implication of MARCKS, RCN3, BAMBI, PEA3/ETV4 and the FK506 family members FKBP7, FKBP10 and FKBP11 in melanoma progression is unclear. Corresponding proteins were detected in melanoma tissue but not in normal skin. High expression of FKBP7, DPYSL5 and MDK was significantly associated with poor survival. We discuss a potential role of these novel melanoma genes, which have promising potential as new therapeutic targets or diagnostic markers.

Tissue-specific composite cell aggregates drive periodontium tissue regeneration by reconstructing a regenerative microenvironment.

PubMed

Zhu, Bin; Liu, Wenjia; Zhang, Hao; Zhao, Xicong; Duan, Yan; Li, Dehua; Jin, Yan

2017-06-01

Periodontitis is the most common cause of periodontium destruction. Regeneration of damaged tissue is the expected treatment goal. However, the regeneration of a functional periodontal ligament (PDL) insertion remains a difficulty, due to complicated factors. Recently, periodontal ligament stem cells (PDLSCs) and bone marrow-derived mesenchymal stem cells (BMMSCs) have been shown to participate in PDL regeneration, both pathologically and physiologically. Besides, interactions affect the biofunctions of different derived cells during the regenerative process. Therefore, the purpose of this study was to discuss the different derived composite cell aggregate (CA) systems of PDLSCs and BMMSCs (iliac-derived or jaw-derived) for periodontium regeneration under regenerative microenvironment reconstruction. Our results showed although all three mono-MSC CAs were compacted and the cells arranged regularly in them, jaw-derived BMMSC (JBMMSC) CAs secreted more extracellular matrix than the others. Furthermore, PDLSC/JBMMSC compound CAs highly expressed ALP, Col-I, fibronectin, integrin-β1 and periostin, suggesting that their biofunction is more appropriate for periodontal structure regeneration. Inspiringly, PDLSC/JBMMSC compound CAs regenerated more functional PDL-like tissue insertions in both nude mice ectopic and minipig orthotopic transplantation. The results indicated that the different derived CAs of PDLSCs/JBMMSCs provided an appropriate regenerative microenvironment facilitating a more stable and regular regeneration of functional periodontium tissue. This method may provide a possible strategy to solve periodontium defects in periodontitis and powerful experimental evidence for clinical applications in the future. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Temporally distinct transcriptional regulation of myocyte dedifferentiation and Myofiber growth during muscle regeneration.

PubMed

Louie, Ke'ale W; Saera-Vila, Alfonso; Kish, Phillip E; Colacino, Justin A; Kahana, Alon

2017-11-09

Tissue regeneration requires a series of steps, beginning with generation of the necessary cell mass, followed by cell migration into damaged area, and ending with differentiation and integration with surrounding tissues. Temporal regulation of these steps lies at the heart of the regenerative process, yet its basis is not well understood. The ability of zebrafish to dedifferentiate mature "post-mitotic" myocytes into proliferating myoblasts that in turn regenerate lost muscle tissue provides an opportunity to probe the molecular mechanisms of regeneration. Following subtotal excision of adult zebrafish lateral rectus muscle, dedifferentiating residual myocytes were collected at two time points prior to cell cycle reentry and compared to uninjured muscles using RNA-seq. Functional annotation (GAGE or K-means clustering followed by GO enrichment) revealed a coordinated response encompassing epigenetic regulation of transcription, RNA processing, and DNA replication and repair, along with protein degradation and translation that would rewire the cellular proteome and metabolome. Selected candidate genes were phenotypically validated in vivo by morpholino knockdown. Rapidly induced gene products, such as the Polycomb group factors Ezh2 and Suz12a, were necessary for both efficient dedifferentiation (i.e. cell reprogramming leading to cell cycle reentry) and complete anatomic regeneration. In contrast, the late activated gene fibronectin was important for efficient anatomic muscle regeneration but not for the early step of myocyte cell cycle reentry. Reprogramming of a "post-mitotic" myocyte into a dedifferentiated myoblast requires a complex coordinated effort that reshapes the cellular proteome and rewires metabolic pathways mediated by heritable yet nuanced epigenetic alterations and molecular switches, including transcription factors and non-coding RNAs. Our studies show that temporal regulation of gene expression is programmatically linked to distinct steps in the regeneration process, with immediate early expression driving dedifferentiation and reprogramming, and later expression facilitating anatomical regeneration.

A functional genomics screen identifies an Importin-α homolog as a regulator of stem cell function and tissue patterning during planarian regeneration.

PubMed

Hubert, Amy; Henderson, Jordana M; Cowles, Martis W; Ross, Kelly G; Hagen, Matthew; Anderson, Christa; Szeterlak, Claudia J; Zayas, Ricardo M

2015-10-12

Planarians are renowned for their regenerative capacity and are an attractive model for the study of adult stem cells and tissue regeneration. In an effort to better understand the molecular mechanisms underlying planarian regeneration, we performed a functional genomics screen aimed at identifying genes involved in this process in Schmidtea mediterranea. We used microarrays to detect changes in gene expression in regenerating and non-regenerating tissues in planarians regenerating one side of the head and followed this with high-throughput screening by in situ hybridization and RNAi to characterize the expression patterns and function of the differentially expressed genes. Along with five previously characterized genes (Smed-cycD, Smed-morf41/mrg-1, Smed-pdss2/dlp1, Smed-slbp, and Smed-tph), we identified 20 additional genes necessary for stem cell maintenance (Smed-sart3, Smed-smarcc-1, Smed-espl1, Smed-rrm2b-1, Smed-rrm2b-2, Smed-dkc1, Smed-emg1, Smed-lig1, Smed-prim2, Smed-mcm7, and a novel sequence) or general regenerative capability (Smed-rbap46/48-2, Smed-mcm2, Smed-ptbp1, and Smed-fen-1) or that caused tissue-specific defects upon knockdown (Smed-ddc, Smed-gas8, Smed-pgbd4, and Smed-b9d2). We also found that a homolog of the nuclear transport factor Importin-α plays a role in stem cell function and tissue patterning, suggesting that controlled nuclear import of proteins is important for regeneration. Through this work, we described the roles of several previously uncharacterized genes in planarian regeneration and implicated nuclear import in this process. We have additionally created an online database to house our in situ and RNAi data to make it accessible to the planarian research community.

Mesenchymal Stem Cells of Dental Origin for Inducing Tissue Regeneration in Periodontitis: A Mini-Review

PubMed Central

Hernández-Monjaraz, Beatriz; Santiago-Osorio, Edelmiro; Monroy-García, Alberto; Ledesma-Martínez, Edgar; Mendoza-Núñez, Víctor Manuel

2018-01-01

Periodontitis is a chronic disease that begins with a period of inflammation of the supporting tissues of the teeth table and then progresses, destroying the tissues until loss of the teeth occurs. The restoration of the damaged dental support apparatus is an extremely complex process due to the regeneration of the cementum, the periodontal ligament, and the alveolar bone. Conventional treatment relies on synthetic materials that fill defects and replace lost dental tissue, but these approaches are not substitutes for a real regeneration of tissue. To address this, there are several approaches to tissue engineering for regenerative dentistry, among them, the use of stem cells. Mesenchymal stem cells (MSC) can be obtained from various sources of adult tissues, such as bone marrow, adipose tissue, skin, and tissues of the orofacial area. MSC of dental origin, such as those found in the bone marrow, have immunosuppressive and immunotolerant properties, multipotency, high proliferation rates, and the capacity for tissue repair. However, they are poorly used as sources of tissue for therapeutic purposes. Their accessibility makes them an attractive source of mesenchymal stem cells, so this review describes the field of dental stem cell research and proposes a potential mechanism involved in periodontal tissue regeneration induced by dental MSC. PMID:29565801

Functionalized mesoporous bioactive glass scaffolds for enhanced bone tissue regeneration

PubMed Central

Zhang, Xingdi; Zeng, Deliang; Li, Nan; Wen, Jin; Jiang, Xinquan; Liu, Changsheng; Li, Yongsheng

2016-01-01

Mesoporous bioactive glass (MBG), which possesses excellent bioactivity, biocompatibility and osteoconductivity, has played an important role in bone tissue regeneration. However, it is difficult to prepare MBG scaffolds with high compressive strength for applications in bone regeneration; this difficulty has greatly hindered its development and use. To solve this problem, a simple powder processing technique has been successfully developed to fabricate a novel type of MBG scaffold (MBGS). Furthermore, amino or carboxylic groups could be successfully grafted onto MBGSs (denoted as N-MBGS and C-MBGS, respectively) through a post-grafting process. It was revealed that both MBGS and the functionalized MBGSs could significantly promote the proliferation and osteogenic differentiation of bMSCs. Due to its positively charged surface, N-MBGS presented the highest in vitro osteogenic capability of the three samples. Moreover, in vivo testing results demonstrated that N-MBGS could promote higher levels of bone regeneration compared with MBGS and C-MBGS. In addition to its surface characteristics, it is believed that the decreased degradation rate of N-MBGS plays a vital role in promoting bone regeneration. These findings indicate that MBGSs are promising materials with potential practical applications in bone regeneration, which can be successfully fabricated by combining a powder processing technique and post-grafting process. PMID:26763311

Functionalized mesoporous bioactive glass scaffolds for enhanced bone tissue regeneration.

PubMed

Zhang, Xingdi; Zeng, Deliang; Li, Nan; Wen, Jin; Jiang, Xinquan; Liu, Changsheng; Li, Yongsheng

2016-01-14

Mesoporous bioactive glass (MBG), which possesses excellent bioactivity, biocompatibility and osteoconductivity, has played an important role in bone tissue regeneration. However, it is difficult to prepare MBG scaffolds with high compressive strength for applications in bone regeneration; this difficulty has greatly hindered its development and use. To solve this problem, a simple powder processing technique has been successfully developed to fabricate a novel type of MBG scaffold (MBGS). Furthermore, amino or carboxylic groups could be successfully grafted onto MBGSs (denoted as N-MBGS and C-MBGS, respectively) through a post-grafting process. It was revealed that both MBGS and the functionalized MBGSs could significantly promote the proliferation and osteogenic differentiation of bMSCs. Due to its positively charged surface, N-MBGS presented the highest in vitro osteogenic capability of the three samples. Moreover, in vivo testing results demonstrated that N-MBGS could promote higher levels of bone regeneration compared with MBGS and C-MBGS. In addition to its surface characteristics, it is believed that the decreased degradation rate of N-MBGS plays a vital role in promoting bone regeneration. These findings indicate that MBGSs are promising materials with potential practical applications in bone regeneration, which can be successfully fabricated by combining a powder processing technique and post-grafting process.

Multimodal-3D imaging based on μMRI and μCT techniques bridges the gap with histology in visualization of the bone regeneration process.

PubMed

Sinibaldi, R; Conti, A; Sinjari, B; Spadone, S; Pecci, R; Palombo, M; Komlev, V S; Ortore, M G; Tromba, G; Capuani, S; Guidotti, R; De Luca, F; Caputi, S; Traini, T; Della Penna, S

2018-03-01

Bone repair/regeneration is usually investigated through X-ray computed microtomography (μCT) supported by histology of extracted samples, to analyse biomaterial structure and new bone formation processes. Magnetic resonance imaging (μMRI) shows a richer tissue contrast than μCT, despite at lower resolution, and could be combined with μCT in the perspective of conducting non-destructive 3D investigations of bone. A pipeline designed to combine μMRI and μCT images of bone samples is here described and applied on samples of extracted human jawbone core following bone graft. We optimized the coregistration procedure between μCT and μMRI images to avoid bias due to the different resolutions and contrasts. Furthermore, we used an Adaptive Multivariate Clustering, grouping homologous voxels in the coregistered images, to visualize different tissue types within a fused 3D metastructure. The tissue grouping matched the 2D histology applied only on 1 slice, thus extending the histology labelling in 3D. Specifically, in all samples, we could separate and map 2 types of regenerated bone, calcified tissue, soft tissues, and/or fat and marrow space. Remarkably, μMRI and μCT alone were not able to separate the 2 types of regenerated bone. Finally, we computed volumes of each tissue in the 3D metastructures, which might be exploited by quantitative simulation. The 3D metastructure obtained through our pipeline represents a first step to bridge the gap between the quality of information obtained from 2D optical microscopy and the 3D mapping of the bone tissue heterogeneity and could allow researchers and clinicians to non-destructively characterize and follow-up bone regeneration. Copyright © 2017 John Wiley & Sons, Ltd.

Comparison of tissue processing methods for microvascular visualization in axolotls.

PubMed

Montoro, Rodrigo; Dickie, Renee

2017-01-01

The vascular system, the pipeline for oxygen and nutrient delivery to tissues, is essential for vertebrate development, growth, injury repair, and regeneration. With their capacity to regenerate entire appendages throughout their lifespan, axolotls are an unparalleled model for vertebrate regeneration, but they lack many of the molecular tools that facilitate vascular imaging in other animal models. The determination of vascular metrics requires high quality image data for the discrimination of vessels from background tissue. Quantification of the vasculature using perfused, cleared specimens is well-established in mammalian systems, but has not been widely employed in amphibians. The objective of this study was to optimize tissue preparation methods for the visualization of the microvascular network in axolotls, providing a basis for the quantification of regenerative angiogenesis. To accomplish this aim, we performed intracardiac perfusion of pigment-based contrast agents and evaluated aqueous and non-aqueous clearing techniques. The methods were verified by comparing the quality of the vascular images and the observable vascular density across treatment groups. Simple and inexpensive, these tissue processing techniques will be of use in studies assessing vascular growth and remodeling within the context of regeneration. Advantages of this method include: •Higher contrast of the vasculature within the 3D context of the surrounding tissue •Enhanced detection of microvasculature facilitating vascular quantification •Compatibility with other labeling techniques.

BRAIN REGENERATION IN PHYSIOLOGY AND PATHOLOGY: THE IMMUNE SIGNATURE DRIVING THERAPEUTIC PLASTICITY OF NEURAL STEM CELLS

PubMed Central

Martino, Gianvito; Pluchino, Stefano; Bonfanti, Luca; Schwartz, Michal

2013-01-01

Regenerative processes occurring under physiological (maintenance) and pathological (reparative) conditions are a fundamental part of life and vary greatly among different species, individuals, and tissues. Physiological regeneration occurs naturally as a consequence of normal cell erosion, or as an inevitable outcome of any biological process aiming at the restoration of homeostasis. Reparative regeneration occurs as a consequence of tissue damage. Although the central nervous system (CNS) has been considered for years as a “perennial” tissue, it has recently become clear that both physiological and reparative regeneration occur also within the CNS to sustain tissue homeostasis and repair. Proliferation and differentiation of neural stem/progenitor cells (NPCs) residing within the healthy CNS, or surviving injury, are considered crucial in sustaining these processes. Thus a large number of experimental stem cell-based transplantation systems for CNS repair have recently been established. The results suggest that transplanted NPCs promote tissue repair not only via cell replacement but also through their local contribution to changes in the diseased tissue milieu. This review focuses on the remarkable plasticity of endogenous and exogenous (transplanted) NPCs in promoting repair. Special attention will be given to the cross-talk existing between NPCs and CNS-resident microglia as well as CNS-infiltrating immune cells from the circulation, as a crucial event sustaining NPC-mediated neuroprotection. Finally, we will propose the concept of the context-dependent potency of transplanted NPCs (therapeutic plasticity) to exert multiple therapeutic actions, such as cell replacement, neurotrophic support, and immunomodulation, in CNS repair. PMID:22013212

Dual-controlled release system of drugs for bone regeneration.

PubMed

Kim, Yang-Hee; Tabata, Yasuhiko

2015-11-01

Controlled release systems have been noted to allow drugs to enhance their ability for bone regeneration. To this end, various biomaterials have been used as the release carriers of drugs, such as low-molecular-weight drugs, growth factors, and others. The drugs are released from the release carriers in a controlled fashion to maintain their actions for a long time period. Most research has been focused on the controlled release of single drugs to demonstrate the therapeutic feasibility. Controlled release of two combined drugs, so-called dual release systems, are promising and important for tissue regeneration. This is because the tissue regeneration process of bone formation is generally achieved by multiple bioactive molecules, which are produced from cells by other molecules. If two types of bioactive molecules, (i.e., drugs), are supplied in an appropriate fashion, the regeneration process of living bodies will be efficiently promoted. This review focuses on the bone regeneration induced by dual-controlled release of drugs. In this paper, various dual-controlled release systems of drugs aiming at bone regeneration are overviewed explaining the type of drugs and their release materials. Copyright © 2015 Elsevier B.V. All rights reserved.

Autoradiographic study on healing process of cysteamine-induced duodenal ulcer in rat. Possible importance of Brunner's glands in ulcer healing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fuse, Y.; Tsuchihashi, Y.; Sugihara, H.

1988-09-01

The healing process of cysteamine-induced duodenal ulcer was studied by (/sup 3/H)thymidine autoradiography. After the development of ulcer in the duodenum, cell proliferation was markedly activated not only in the crypts but also in the Brunner's glands near the ulcer. In the initial stages of ulcer healing, they both contributed to form the surface covering regenerating epithelium. Granulation tissue also proliferated at the base of the ulcer. In later stages of ulcer healing, new crypts were formed in the floor of the ulcer. New villi regenerated from these crypts and Brunner's glands regenerated by proliferation in situ. The ulcer basemore » then was completely covered with new villi and granulation tissue was replaced by dense fibrous connective tissue. The present study suggested that the Brunner's glands, together with the crypts of Lieberkuehn, play an important role in the healing process of cysteamine-induced duodenal ulcer.« less

Changes in Regenerative Capacity through Lifespan

PubMed Central

Yun, Maximina H.

2015-01-01

Most organisms experience changes in regenerative abilities through their lifespan. During aging, numerous tissues exhibit a progressive decline in homeostasis and regeneration that results in tissue degeneration, malfunction and pathology. The mechanisms responsible for this decay are both cell intrinsic, such as cellular senescence, as well as cell-extrinsic, such as changes in the regenerative environment. Understanding how these mechanisms impact on regenerative processes is essential to devise therapeutic approaches to improve tissue regeneration and extend healthspan. This review offers an overview of how regenerative abilities change through lifespan in various organisms, the factors that underlie such changes and the avenues for therapeutic intervention. It focuses on established models of mammalian regeneration as well as on models in which regenerative abilities do not decline with age, as these can deliver valuable insights for our understanding of the interplay between regeneration and aging. PMID:26512653

Possible role of mechanical force in regulating regeneration of the vascularized fat flap inside a tissue engineering chamber.

PubMed

Ye, Yuan; Yuan, Yi; Lu, Feng; Gao, Jianhua

2015-12-01

In plastic and reconstructive surgery, adipose tissue is widely used as effective filler for tissue defects. Strategies for treating soft tissue deficiency, which include free adipose tissue grafts, use of hyaluronic acid, collagen injections, and implantation of synthetic materials, have several clinical limitations. With the aim of overcoming these limitations, researchers have recently utilized tissue engineering chambers to produce large volumes of engineered vascularized fat tissue. However, the process of growing fat tissue in a chamber is still relatively limited, and can result in unpredictable or dissatisfactory final tissue volumes. Therefore, detailed understanding of the process is both necessary and urgent. Many studies have shown that mechanical force can change the function of cells via mechanotransduction. Here, we hypothesized that, besides the inflammatory response, one of the key factors to control the regeneration of vascularized fat flap inside a tissue engineering chamber might be the balance of mechanical forces. To test our hypothesis, we intend to change the balance of forces by means of measures in order to make the equilibrium point in favor of the direction of regeneration. If those measures proved to be feasible, they could be applied in clinical practice to engineer vascularized adipose tissue of predictable size and shape, which would in turn help in the advancement of tissue engineering. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rejuvenating Strategies for Stem Cell-based Therapies in Aging

PubMed Central

Neves, Joana; Sousa-Victor, Pedro; Jasper, Heinrich

2017-01-01

SUMMARY Recent advances in our understanding of tissue regeneration and the development of efficient approaches to induce and differentiate pluripotent stem cells for cell replacement therapies promise exciting avenues for treating degenerative age-related diseases. However, clinical studies and insights from model organisms have identified major roadblocks that normal aging processes impose on tissue regeneration. These new insights suggest that specific targeting of environmental niche components, including growth factors, ECM and immune cells, and intrinsic stem cell properties that are affected by aging will be critical for development of new strategies to improve stem cell function and optimize tissue repair processes. PMID:28157498

Computational model-informed design and bioprinting of cell-patterned constructs for bone tissue engineering.

PubMed

Carlier, Aurélie; Skvortsov, Gözde Akdeniz; Hafezi, Forough; Ferraris, Eleonora; Patterson, Jennifer; Koç, Bahattin; Van Oosterwyck, Hans

2016-05-17

Three-dimensional (3D) bioprinting is a rapidly advancing tissue engineering technology that holds great promise for the regeneration of several tissues, including bone. However, to generate a successful 3D bone tissue engineering construct, additional complexities should be taken into account such as nutrient and oxygen delivery, which is often insufficient after implantation in large bone defects. We propose that a well-designed tissue engineering construct, that is, an implant with a specific spatial pattern of cells in a matrix, will improve the healing outcome. By using a computational model of bone regeneration we show that particular cell patterns in tissue engineering constructs are able to enhance bone regeneration compared to uniform ones. We successfully bioprinted one of the most promising cell-gradient patterns by using cell-laden hydrogels with varying cell densities and observed a high cell viability for three days following the bioprinting process. In summary, we present a novel strategy for the biofabrication of bone tissue engineering constructs by designing cell-gradient patterns based on a computational model of bone regeneration, and successfully bioprinting the chosen design. This integrated approach may increase the success rate of implanted tissue engineering constructs for critical size bone defects and also can find a wider application in the biofabrication of other types of tissue engineering constructs.

Plant grafting: insights into tissue regeneration.

PubMed

Melnyk, Charles W

2017-02-01

For millennia, people have cut and joined different plants together through a process known as grafting. The severed tissues adhere, the cells divide and the vasculature differentiates through a remarkable process of regeneration between two genetically distinct organisms as they become one. Grafting is becoming increasingly important in horticulture where it provides an efficient means for asexual propagation. Grafting also combines desirable roots and shoots to generate chimeras that are more vigorous, more pathogen resistant and more abiotic stress resistant. Thus, it presents an elegant and efficient way to improve plant productivity in vegetables and trees using traditional techniques. Despite this horticultural importance, we are only beginning to understand how plants regenerate tissues at the graft junction. By understanding grafting better, we can shed light on fundamental regeneration pathways and the basis for self/non-self recognition. We can also better understand why many plants efficiently graft whereas others cannot, with the goal of improving grafting so as to broaden the range of grafted plants to create even more desirable chimeras. Here, I review the latest findings describing how plants graft and provide insight into future directions in this emerging field.

A myogenic precursor cell that could contribute to regeneration in zebrafish and its similarity to the satellite cell.

PubMed

Siegel, Ashley L; Gurevich, David B; Currie, Peter D

2013-09-01

The cellular basis for mammalian muscle regeneration has been an area of intense investigation over recent decades. The consensus is that a specialized self-renewing stem cell, termed the satellite cell, plays a major role during the process of regeneration in amniotes. How broadly this mechanism is deployed within the vertebrate phylogeny remains an open question. A lack of information on the role of cells analogous to the satellite cell in other vertebrate systems is even more unexpected given the fact that satellite cells were first designated in frogs. An intriguing aspect of this debate is that a number of amphibia and many fish species exhibit epimorphic regenerative processes in specific tissues, whereby regeneration occurs by the dedifferentiation of the damaged tissue, without deploying specialized stem cell populations analogous to satellite cells. Hence, it is feasible that a cellular process completely distinct from that deployed during mammalian muscle regeneration could operate in species capable of epimorphic regeneration. In this minireview, we examine the evidence for the broad phylogenetic distribution of satellite cells. We conclude that, in the vertebrates examined so far, epimorphosis does not appear to be deployed during muscle regeneration, and that analogous cells expressing similar marker genes to satellite cells appear to be deployed during the regenerative process. However, the functional definition of these cells as self-renewing muscle stem cells remains a final hurdle to the definition of the satellite cell as a generic vertebrate cell type. © 2013 FEBS.

* Animal Models for Periodontal Tissue Engineering: A Knowledge-Generating Process.

PubMed

Fawzy El-Sayed, Karim M; Dörfer, Christof E

2017-12-01

The human periodontium is a uniquely complex vital structure, supporting and anchoring the teeth in their alveolar sockets, thereby playing a decisive role in tooth homeostasis and function. Chronic periodontitis is a highly prevalent immune-inflammatory disease of the periodontium, affecting 15% of adult individuals, and is characterized by progressive destruction of the periodontal tooth-investing tissues, culminating in their irreversible damage. Current periodontal evidence-based treatment strategies achieve periodontal healing via repair processes, mostly combating the inflammatory component of the disease, to halt or reduce prospective periodontal tissue loss. However, complete periodontal tissue regeneration remains a hard fought-for goal in the field of periodontology and multiple in vitro and in vivo studies have been conducted, in the conquest to achieve a functional periodontal tissue regeneration in humans. The present review evaluates the current status of periodontal regeneration attempted through tissue-engineering concepts, ideal requirements for experimental animal models under investigation, the methods of induction and classification of the experimentally created periodontal defects, types of experimental defects employed in the diverse animal studies, as well as the current state of knowledge obtained from in vivo animal experiments, with special emphasis on large animal models.

Germline Transgenic Methods for Tracking Cells and Testing Gene Function during Regeneration in the Axolotl

PubMed Central

Khattak, Shahryar; Schuez, Maritta; Richter, Tobias; Knapp, Dunja; Haigo, Saori L.; Sandoval-Guzmán, Tatiana; Hradlikova, Kristyna; Duemmler, Annett; Kerney, Ryan; Tanaka, Elly M.

2013-01-01

The salamander is the only tetrapod that regenerates complex body structures throughout life. Deciphering the underlying molecular processes of regeneration is fundamental for regenerative medicine and developmental biology, but the model organism had limited tools for molecular analysis. We describe a comprehensive set of germline transgenic strains in the laboratory-bred salamander Ambystoma mexicanum (axolotl) that open up the cellular and molecular genetic dissection of regeneration. We demonstrate tissue-dependent control of gene expression in nerve, Schwann cells, oligodendrocytes, muscle, epidermis, and cartilage. Furthermore, we demonstrate the use of tamoxifen-induced Cre/loxP-mediated recombination to indelibly mark different cell types. Finally, we inducibly overexpress the cell-cycle inhibitor p16INK4a, which negatively regulates spinal cord regeneration. These tissue-specific germline axolotl lines and tightly inducible Cre drivers and LoxP reporter lines render this classical regeneration model molecularly accessible. PMID:24052945

Impaired tissue regeneration corresponds with altered expression of developmental genes that persists in the metabolic memory state of diabetic zebrafish

PubMed Central

Sarras, Michael P.; Leontovich, Alexey A.; Olsen, Ansgar S.; Intine, Robert V.

2013-01-01

As previously reported by our lab streptozocin-induced Diabetes mellitus (DM) in adult zebrafish results in an impairment of tissue regeneration as monitored by caudal fin regeneration. Following streptozocin withdrawal, a recovery phase occurs to re-establish euglycemia, via pancreatic beta-cell regeneration. However, DM-associated impaired fin regeneration continues indefinitely in the metabolic memory state (MM) allowing for subsequent molecular analysis of the underlying mechanisms of MM. This study focuses on elucidating the molecular basis that explains the DM-associated impaired fin regeneration and why it persists into the MM state with the aim of better understanding MM. Using a combination of microarray analysis and bioinformatics approaches our study found that of the 14,900 transcripts analyzed, aberrant expression of 71 genes relating to tissue developmental and regeneration processes were identified in DM fish and the altered expression of these 71 genes persisted in MM fish. Key regulatory genes of major development, and signal transduction pathways were identified among this group of 71. The aberrant expression of key regulatory genes in the DM state that persist into the MM state provides a plausible explanation for how hyperglycemia induced impaired fin regeneration in the adult zebrafish DM/MM model. PMID:23438205

Biomimetic approaches with smart interfaces for bone regeneration.

PubMed

Sailaja, G S; Ramesh, P; Vellappally, Sajith; Anil, Sukumaran; Varma, H K

2016-11-05

A 'smart tissue interface' is a host tissue-biomaterial interface capable of triggering favourable biochemical events inspired by stimuli responsive mechanisms. In other words, biomaterial surface is instrumental in dictating the interface functionality. This review aims to investigate the fundamental and favourable requirements of a 'smart tissue interface' that can positively influence the degree of healing and promote bone tissue regeneration. A biomaterial surface when interacts synergistically with the dynamic extracellular matrix, the healing process become accelerated through development of a smart interface. The interface functionality relies equally on bound functional groups and conjugated molecules belonging to the biomaterial and the biological milieu it interacts with. The essential conditions for such a special biomimetic environment are discussed. We highlight the impending prospects of smart interfaces and trying to relate the design approaches as well as critical factors that determine species-specific functionality with special reference to bone tissue regeneration.

Biomaterial-mediated strategies targeting vascularization for bone repair.

PubMed

García, José R; García, Andrés J

2016-04-01

Repair of non-healing bone defects through tissue engineering strategies remains a challenging feat in the clinic due to the aversive microenvironment surrounding the injured tissue. The vascular damage that occurs following a bone injury causes extreme ischemia and a loss of circulating cells that contribute to regeneration. Tissue-engineered constructs aimed at regenerating the injured bone suffer from complications based on the slow progression of endogenous vascular repair and often fail at bridging the bone defect. To that end, various strategies have been explored to increase blood vessel regeneration within defects to facilitate both tissue-engineered and natural repair processes. Developments that induce robust vascularization will need to consolidate various parameters including optimization of embedded therapeutics, scaffold characteristics, and successful integration between the construct and the biological tissue. This review provides an overview of current strategies as well as new developments in engineering biomaterials to induce reparation of a functional vascular supply in the context of bone repair.

Scaffolds to Control Inflammation and Facilitate Dental Pulp Regeneration

PubMed Central

Colombo, John S.; Moore, Amanda N.; Hartgerink, Jeffrey D.; D’Souza, Rena N.

2014-01-01

In dentistry, the maintenance of a vital dental pulp is of paramount importance, as teeth devitalized by root canal treatment may become more brittle and prone to structural failure over time. Advanced carious lesions can irreversibly damage the dental pulp by propagating a sustained inflammatory response throughout the tissue. While the inflammatory response initially drives tissue repair, sustained inflammation has an enormously destructive effect on the vital pulp, eventually leading to total necrosis of the tissue and necessitating its removal. The implications of tooth devitalization have driven significant interest in the development of bioactive materials that facilitate the regeneration of damaged pulp tissues by harnessing the capacity of the dental pulp for self-repair. In considering the process by which pulpitis drives tissue destruction, it is clear that an important step in supporting the regeneration of pulpal tissues is the attenuation of inflammation. Macrophages, key mediators of the immune response, may play a critical role in the resolution of pulpitis due to their ability to switch to a pro-resolution phenotype. This process can be driven by the resolvins, a family of molecules derived from fatty acids that show great promise as therapeutic agents. In this review, we outline the importance of preserving the capacity of the dental pulp to self-repair through the rapid attenuation of inflammation. Potential treatment modalities, such as shifting macrophages to a pro-resolving phenotype with resolvins are described, and a range of materials known to support the regeneration of dental pulp are presented. PMID:24698696

Multiphasic Scaffolds for Periodontal Tissue Engineering

PubMed Central

Ivanovski, S.; Vaquette, C.; Gronthos, S.; Hutmacher, D.W.; Bartold, P.M.

2014-01-01

For a successful clinical outcome, periodontal regeneration requires the coordinated response of multiple soft and hard tissues (periodontal ligament, gingiva, cementum, and bone) during the wound-healing process. Tissue-engineered constructs for regeneration of the periodontium must be of a complex 3-dimensional shape and adequate size and demonstrate biomechanical stability over time. A critical requirement is the ability to promote the formation of functional periodontal attachment between regenerated alveolar bone, and newly formed cementum on the root surface. This review outlines the current advances in multiphasic scaffold fabrication and how these scaffolds can be combined with cell- and growth factor–based approaches to form tissue-engineered constructs capable of recapitulating the complex temporal and spatial wound-healing events that will lead to predictable periodontal regeneration. This can be achieved through a variety of approaches, with promising strategies characterized by the use of scaffolds that can deliver and stabilize cells capable of cementogenesis onto the root surface, provide biomechanical cues that encourage perpendicular alignment of periodontal fibers to the root surface, and provide osteogenic cues and appropriate space to facilitate bone regeneration. Progress on the development of multiphasic constructs for periodontal tissue engineering is in the early stages of development, and these constructs need to be tested in large animal models and, ultimately, human clinical trials. PMID:25139362

Multiphasic scaffolds for periodontal tissue engineering.

PubMed

Ivanovski, S; Vaquette, C; Gronthos, S; Hutmacher, D W; Bartold, P M

2014-12-01

For a successful clinical outcome, periodontal regeneration requires the coordinated response of multiple soft and hard tissues (periodontal ligament, gingiva, cementum, and bone) during the wound-healing process. Tissue-engineered constructs for regeneration of the periodontium must be of a complex 3-dimensional shape and adequate size and demonstrate biomechanical stability over time. A critical requirement is the ability to promote the formation of functional periodontal attachment between regenerated alveolar bone, and newly formed cementum on the root surface. This review outlines the current advances in multiphasic scaffold fabrication and how these scaffolds can be combined with cell- and growth factor-based approaches to form tissue-engineered constructs capable of recapitulating the complex temporal and spatial wound-healing events that will lead to predictable periodontal regeneration. This can be achieved through a variety of approaches, with promising strategies characterized by the use of scaffolds that can deliver and stabilize cells capable of cementogenesis onto the root surface, provide biomechanical cues that encourage perpendicular alignment of periodontal fibers to the root surface, and provide osteogenic cues and appropriate space to facilitate bone regeneration. Progress on the development of multiphasic constructs for periodontal tissue engineering is in the early stages of development, and these constructs need to be tested in large animal models and, ultimately, human clinical trials. © International & American Associations for Dental Research.

Mathematical Model of Bone Regeneration in a Porous Implant

NASA Astrophysics Data System (ADS)

Maslov, L. B.

2017-07-01

A mathematical model of the reparative regeneration of bone tissue governed by the law of cell differentiation and action of an external periodic mechanical loading is presented. The model allows one to study the recovery processes of injured human locomotor system elements under a dynamic loading and to theoretically substantiate the choice of an optimum periodic impact on the defective tissues for their fastest and steady healing.

A transcriptional time-course analysis of oral vs. aboral whole-body regeneration in the Sea anemone Nematostella vectensis.

PubMed

Schaffer, Amos A; Bazarsky, Michael; Levy, Karine; Chalifa-Caspi, Vered; Gat, Uri

2016-09-07

The ability of regeneration is essential for the homeostasis of all animals as it allows the repair and renewal of tissues and body parts upon normal turnover or injury. The extent of this ability varies greatly in different animals with the sea anemone Nematostella vectensis, a basal cnidarian model animal, displaying remarkable whole-body regeneration competence. In order to study this process in Nematostella we performed an RNA-Seq screen wherein we analyzed and compared the transcriptional response to bisection in the wound-proximal body parts undergoing oral (head) or aboral (tail) regeneration at several time points up to the initial restoration of the basic body shape. The transcriptional profiles of regeneration responsive genes were analyzed so as to define the temporal pattern of differential gene expression associated with the tissue-specific oral and aboral regeneration. The identified genes were characterized according to their GO (gene ontology) assignations revealing groups that were enriched in the regeneration process with particular attention to their affiliation to the major developmental signaling pathways. While some of the genes and gene groups thus analyzed were previously known to be active in regeneration, we have also revealed novel and surprising candidate genes such as cilia-associated genes that likely participate in this important developmental program. This work highlighted the main groups of genes which showed polarization upon regeneration, notably the proteinases, multiple transcription factors and the Wnt pathway genes that were highly represented, all displaying an intricate temporal balance between the two sides. In addition, the evolutionary comparison performed between regeneration in different animal model systems may reveal the basic mechanisms playing a role in this fascinating process.

Lizard tail regeneration as an instructive model of enhanced healing capabilities in an adult amniote.

PubMed

Lozito, Thomas P; Tuan, Rocky S

2017-03-01

The ability to regenerate damaged or lost tissues has remained the lofty goal of regenerative medicine. Unfortunately, humans, like most mammals, suffer from very minimal natural regenerative capabilities. Certain non-mammalian animal species, however, are not so limited in their healing capabilities, and several have attracted the attention of researchers hoping to recreate enhanced healing responses in humans. This review focuses on one such animal group with remarkable regenerative abilities, the lizards. As the closest relatives of mammals that exhibit enhanced regenerative abilities as adults, lizards potentially represent the most relevant model for direct comparison and subsequent improvement of mammalian healing. Lizards are able to regenerate amputated tails and exhibit adaptations that both limit tissue damage in response to injury and initiate coordinated regenerative responses. This review summarizes the salient aspects of lizard tail regeneration as they relate to the overall regenerative process and also presents the relevant information pertaining to regrowth of specific tissues, including skeletal, muscular, nervous, and vascular tissues. The goal of this review is to introduce the topic of lizard tail regeneration to new audiences with the hope of expanding the knowledge base of this underutilized but potentially powerful model organism.

Tail regeneration in Urodela: old model and new perspectives in studies

NASA Astrophysics Data System (ADS)

Grigoryan, E.; Anton, H.; Mitashov, V.

For better understanding of micro-"g" effect on nervous tissue regeneration we have chosen the regeneration of the Urodele tail, because it utilizes many developmental processes and represents the most convenient model for experiments in Space. The special interesting aspect lies in the ability of regenerates to differentiate the spinal cord (SC) and this, in turn, has a potential of practical application. Meanwhile there are conclusive evidences suggesting the production by SC cells the neurotrophic factors promoting cell proliferation and differentiation in growing tail regenerate. Previously our studies on tail regeneration in the adult newt showed that the force of gravity clearly inf luences the events underlying the regeneration. We reported the significant increase of tail regeneration rate and tissue volume of tail regenerates in the newts exposed to real and simulated low "g". In Bion 11 mission animals that were exposed 14 days in microgravity and whose tails were operated two and four weeks before launch demonstrated the regenerates achieved 1.5 - 2 times the volume of those in 1"g" control. Results of this experiment indicated also that the regeneration of central and peripheral neurons and nerve fibers was carrying out faster under low "g" conditions than in 1 "g" control. Similar data were obtained in several experiments remodeling physiological weightlessness by mean of the clinostat. It led us to the hypothesis that the stimulation of tail regeneration is linked with an over activation of neurotrophic factors produced by quickly growing SC neurons. Now we've completed the experiment on tail regeneration in the newts Tr. alpestris subjected to 5 day long clinorotation after 6 days post tail amputation. The rate of primary- and secondary regeneration was evaluated at different time points after treatment. Cell proliferation, differentiation and expression of neurotrophic proteins in SC and other major tissue-type of regenerate were investigated by immunohistochemistry. Results we've just obtained previously support our proposition on the accelerating effect of micro-"g" upon SC regeneration and then of other tail tissue in the newt. The effect, in turn, could be mediated by increased expression of neurotrophins.

Applications of Metals for Bone Regeneration.

PubMed

Glenske, Kristina; Donkiewicz, Phil; Köwitsch, Alexander; Milosevic-Oljaca, Nada; Rider, Patrick; Rofall, Sven; Franke, Jörg; Jung, Ole; Smeets, Ralf; Schnettler, Reinhard; Wenisch, Sabine; Barbeck, Mike

2018-03-12

The regeneration of bone tissue is the main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP)-based substitute materials based on natural (allo- and xenografts) and synthetic origins (alloplastic materials) are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, as well as resorb in the time frame needed for complete regeneration up to the condition of restitution ad integrum . In this context, the modes of action of CaP-based substitute materials have been frequently investigated, where it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between new bone tissue formation and material degradation has not been found, until now. The addition of different substances such as collagen or growth factors and also of different cell types has already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are used differently as a basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue, playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designed for bone regeneration, with the aim to provide an overview of currently existing knowledge about the effects of metals in the field of bone regeneration.

Applications of Metals for Bone Regeneration

PubMed Central

Glenske, Kristina; Donkiewicz, Phil; Köwitsch, Alexander; Milosevic-Oljaca, Nada; Rider, Patrick; Rofall, Sven; Franke, Jörg; Jung, Ole; Smeets, Ralf; Schnettler, Reinhard; Wenisch, Sabine

2018-01-01

The regeneration of bone tissue is the main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP)-based substitute materials based on natural (allo- and xenografts) and synthetic origins (alloplastic materials) are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, as well as resorb in the time frame needed for complete regeneration up to the condition of restitution ad integrum. In this context, the modes of action of CaP-based substitute materials have been frequently investigated, where it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between new bone tissue formation and material degradation has not been found, until now. The addition of different substances such as collagen or growth factors and also of different cell types has already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are used differently as a basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue, playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designed for bone regeneration, with the aim to provide an overview of currently existing knowledge about the effects of metals in the field of bone regeneration. PMID:29534546

Djhsp90s are crucial regulators during planarian regeneration and tissue homeostasis.

PubMed

Dong, Zimei; Chu, Gengbo; Sima, Yingxu; Chen, Guangwen

2018-04-15

Heat shock protein 90 family members (HSP90s), as molecular chaperones, have conserved roles in the physiological processes of eukaryotes regulating cytoprotection, increasing host resistance and so on. However, whether HSP90s affect regeneration in animals is unclear. Planarians are emerging models for studying regeneration in vivo. Here, the roles of three hsp90 genes from planarian Dugesia japonica are investigated by WISH and RNAi. The results show that: (1) Djhsp90s expressions are induced by heat and cold shock, tissue damage and ionic liquid; (2) Djhsp90s mRNA are mainly distributed each side of the body in intact worms as well as blastemas in regenerative worms; (3) the worms show head regression, lysis, the body curling and the regeneration arrest or even failure after Djhsp90s RNAi; (4) Djhsp90s are involved in autophagy and locomotion of the body. The research results suggest that Djhsp90s are not only conserved in cytoprotection, but also involved in homeostasis maintenance and regeneration process by regulating different pathways in planarians. Copyright © 2018 Elsevier Inc. All rights reserved.

Triggerable Degradation of Polyurethanes for Tissue Engineering Applications.

PubMed

Xu, Cancan; Huang, Yihui; Wu, Jinglei; Tang, Liping; Hong, Yi

2015-09-16

Tissue engineered and bioactive scaffolds with different degradation rates are required for the regeneration of diverse tissues/organs. To optimize tissue regeneration in different tissues, it is desirable that the degradation rate of scaffolds can be manipulated to comply with various stages of tissue regeneration. Unfortunately, the degradation of most degradable polymers relies solely on passive controlled degradation mechanisms. To overcome this challenge, we report a new family of reduction-sensitive biodegradable elastomeric polyurethanes containing various amounts of disulfide bonds (PU-SS), in which degradation can be initiated and accelerated with the supplement of a biological product: antioxidant-glutathione (GSH). The polyurethanes can be processed into films and electrospun fibrous scaffolds. Synthesized materials exhibited robust mechanical properties and high elasticity. Accelerated degradation of the materials was observed in the presence of GSH, and the rate of such degradation depends on the amount of disulfide present in the polymer backbone. The polymers and their degradation products exhibited no apparent cell toxicity while the electrospun scaffolds supported fibroblast growth in vitro. The in vivo subcutaneous implantation model showed that the polymers prompt minimal inflammatory responses, and as anticipated, the polymer with the higher disulfide bond amount had faster degradation in vivo. This new family of polyurethanes offers tremendous potential for directed scaffold degradation to promote maximal tissue regeneration.

Ex vivo method to visualize and quantify vascular networks in native and tissue engineered skin.

PubMed

Egaña, José Tomás; Condurache, Alexandru; Lohmeyer, Jörn Andreas; Kremer, Mathias; Stöckelhuber, Beate M; Lavandero, Sergio; Machens, Hans-Günther

2009-03-01

Neovascularization plays a pivotal role in tissue engineering and tissue regeneration. However, reliable technologies to visualize and quantify blood vessel networks in target tissue areas are still pending. In this work, we introduce a new method which allows comparing vascularization levels in normal and tissue-engineered skin. Normal skin was isolated, and vascular dermal regeneration was analyzed based on tissue transillumination and computerized digital segmentation. For tissue-engineered skin, a bilateral full skin defect was created in a nude mouse model and then covered with a commercially available scaffold for dermal regeneration. After 3 weeks, the whole skin (including scaffold for dermal regeneration) was harvested, and vascularization levels were analyzed. The blood vessel network in the skin was better visualized by transillumination than by radio-angiographic studies, the gold standard for angiographies. After visualization, the whole vascular network was digitally segmented showing an excellent overlapping with the original pictures. Quantification over the digitally segmented picture was performed, and an index of vascularization area (VAI) and length (VLI) of the vessel network was obtained in target tissues. VAI/VLI ratio was calculated to obtain the vessel size index. We present a new technique which has several advantages compared to others, as animals do not require intravascular perfusions, total areas of interest can be quantitatively analyzed at once, and the same target tissue can be processed for further experimental analysis.

Analysis of the Function of Apoptosis during Imaginal Wing Disc Regeneration in Drosophila melanogaster.

PubMed

Diaz-Garcia, Sandra; Ahmed, Sara; Baonza, Antonio

2016-01-01

Regeneration is the ability that allows organisms to replace missing organs or lost tissue after injuries. This ability requires the coordinated activity of different cellular processes, including programmed cell death. Apoptosis plays a key role as a source of signals necessary for regeneration in different organisms. The imaginal discs of Drosophila melanogaster provide a particularly well-characterised model system for studying the cellular and molecular mechanisms underlying regeneration. Although it has been shown that signals produced by apoptotic cells are needed for homeostasis and regeneration of some tissues of this organism, such as the adult midgut, the contribution of apoptosis to disc regeneration remains unclear. Using a new method for studying disc regeneration in physiological conditions, we have defined the pattern of cell death in regenerating discs. Our data indicate that during disc regeneration, cell death increases first at the wound edge, but as regeneration progresses dead cells can be observed in regions far away from the site of damage. This result indicates that apoptotic signals initiated in the wound spread throughout the disc. We also present results which suggest that the partial inhibition of apoptosis does not have a major effect on disc regeneration. Finally, our results suggest that during disc regeneration distinct apoptotic signals might be acting simultaneously.

Harnessing biomechanics to develop cartilage regeneration strategies.

PubMed

Athanasiou, Kyriacos A; Responte, Donald J; Brown, Wendy E; Hu, Jerry C

2015-02-01

As this review was prepared specifically for the American Society of Mechanical Engineers H.R. Lissner Medal, it primarily discusses work toward cartilage regeneration performed in Dr. Kyriacos A. Athanasiou's laboratory over the past 25 years. The prevalence and severity of degeneration of articular cartilage, a tissue whose main function is largely biomechanical, have motivated the development of cartilage tissue engineering approaches informed by biomechanics. This article provides a review of important steps toward regeneration of articular cartilage with suitable biomechanical properties. As a first step, biomechanical and biochemical characterization studies at the tissue level were used to provide design criteria for engineering neotissues. Extending this work to the single cell and subcellular levels has helped to develop biochemical and mechanical stimuli for tissue engineering studies. This strong mechanobiological foundation guided studies on regenerating hyaline articular cartilage, the knee meniscus, and temporomandibular joint (TMJ) fibrocartilage. Initial tissue engineering efforts centered on developing biodegradable scaffolds for cartilage regeneration. After many years of studying scaffold-based cartilage engineering, scaffoldless approaches were developed to address deficiencies of scaffold-based systems, resulting in the self-assembling process. This process was further improved by employing exogenous stimuli, such as hydrostatic pressure, growth factors, and matrix-modifying and catabolic agents, both singly and in synergistic combination to enhance neocartilage functional properties. Due to the high cell needs for tissue engineering and the limited supply of native articular chondrocytes, costochondral cells are emerging as a suitable cell source. Looking forward, additional cell sources are investigated to render these technologies more translatable. For example, dermis isolated adult stem (DIAS) cells show potential as a source of chondrogenic cells. The challenging problem of enhanced integration of engineered cartilage with native cartilage is approached with both familiar and novel methods, such as lysyl oxidase (LOX). These diverse tissue engineering strategies all aim to build upon thorough biomechanical characterizations to produce functional neotissue that ultimately will help combat the pressing problem of cartilage degeneration. As our prior research is reviewed, we look to establish new pathways to comprehensively and effectively address the complex problems of musculoskeletal cartilage regeneration.

Gradient biomaterials and their influences on cell migration

PubMed Central

Wu, Jindan; Mao, Zhengwei; Tan, Huaping; Han, Lulu; Ren, Tanchen; Gao, Changyou

2012-01-01

Cell migration participates in a variety of physiological and pathological processes such as embryonic development, cancer metastasis, blood vessel formation and remoulding, tissue regeneration, immune surveillance and inflammation. The cells specifically migrate to destiny sites induced by the gradually varying concentration (gradient) of soluble signal factors and the ligands bound with the extracellular matrix in the body during a wound healing process. Therefore, regulation of the cell migration behaviours is of paramount importance in regenerative medicine. One important way is to create a microenvironment that mimics the in vivo cellular and tissue complexity by incorporating physical, chemical and biological signal gradients into engineered biomaterials. In this review, the gradients existing in vivo and their influences on cell migration are briefly described. Recent developments in the fabrication of gradient biomaterials for controlling cellular behaviours, especially the cell migration, are summarized, highlighting the importance of the intrinsic driving mechanism for tissue regeneration and the design principle of complicated and advanced tissue regenerative materials. The potential uses of the gradient biomaterials in regenerative medicine are introduced. The current and future trends in gradient biomaterials and programmed cell migration in terms of the long-term goals of tissue regeneration are prospected. PMID:23741610

Nanocomposites for bone tissue regeneration.

PubMed

Sahoo, Nanda Gopal; Pan, Yong Zheng; Li, Lin; He, Chao Bin

2013-04-01

Natural bone tissue possesses a nanocomposite structure that provides appropriate physical and biological properties. For bone tissue regeneration, it is crucial for the biomaterial to mimic living bone tissue. Since no single type of material is able to mimic the composition, structure and properties of native bone, nanocomposites are the best choice for bone tissue regeneration as they can provide the appropriate matrix environment, integrate desirable biological properties, and provide controlled, sequential delivery of multiple growth factors for the different stages of bone tissue regeneration. This article reviews the composition, structure and properties of advanced nanocomposites for bone tissue regeneration. It covers aspects of interest such as the biomimetic synthesis of bone-like nanocomposites, guided bone regeneration from inert biomaterials and bioactive nanocomposites, and nanocomposite scaffolds for bone tissue regeneration. The design, fabrication, and in vitro and in vivo characterization of such nanocomposites are reviewed.

Instructive microenvironments in skin wound healing: Biomaterials as signal releasing platforms.

PubMed

Castaño, Oscar; Pérez-Amodio, Soledad; Navarro-Requena, Claudia; Mateos-Timoneda, Miguel Ángel; Engel, Elisabeth

2018-04-05

Skin wound healing aims to repair and restore tissue through a multistage process that involves different cells and signalling molecules that regulate the cellular response and the dynamic remodelling of the extracellular matrix. Nowadays, several therapies that combine biomolecule signals (growth factors and cytokines) and cells are being proposed. However, a lack of reliable evidence of their efficacy, together with associated issues such as high costs, a lack of standardization, no scalable processes, and storage and regulatory issues, are hampering their application. In situ tissue regeneration appears to be a feasible strategy that uses the body's own capacity for regeneration by mobilizing host endogenous stem cells or tissue-specific progenitor cells to the wound site to promote repair and regeneration. The aim is to engineer instructive systems to regulate the spatio-temporal delivery of proper signalling based on the biological mechanisms of the different events that occur in the host microenvironment. This review describes the current state of the different signal cues used in wound healing and skin regeneration, and their combination with biomaterial supports to create instructive microenvironments for wound healing. Copyright © 2018 Elsevier B.V. All rights reserved.

The Hippo pathway in intestinal regeneration and disease.

PubMed

Hong, Audrey W; Meng, Zhipeng; Guan, Kun-Liang

2016-06-01

The Hippo pathway is a signalling cascade conserved from Drosophila melanogaster to mammals. The mammalian core kinase components comprise MST1 and MST2, SAV1, LATS1 and LATS2 and MOB1A and MOB1B. The transcriptional co-activators YAP1 and TAZ are the downstream effectors of the Hippo pathway and regulate target gene expression. Hippo signalling has crucial roles in the control of organ size, tissue homeostasis and regeneration, and dysregulation of the Hippo pathway can lead to uncontrolled cell growth and malignant transformation. Mammalian intestine consists of a stem cell compartment as well as differentiated cells, and its ability to regenerate rapidly after injury makes it an excellent model system to study tissue homeostasis, regeneration and tumorigenesis. Several studies have established the important role of the Hippo pathway in these processes. In addition, crosstalk between Hippo and other signalling pathways provides tight, yet versatile, regulation of tissue homeostasis. In this Review, we summarize studies on the role of the Hippo pathway in the intestine on these physiological processes and the underlying mechanisms responsible, and discuss future research directions and potential therapeutic strategies targeting Hippo signalling in intestinal disease.

The Hippo pathway in intestinal regeneration and disease

PubMed Central

Hong, Audrey W.; Meng, Zhipeng; Guan, Kun-Liang

2017-01-01

The Hippo pathway is a signalling cascade conserved from Drosophila melanogaster to mammals. The mammalian core kinase components comprise MST1 and MST2, SAV1, LATS1 and LATS2 and MOB1A and MOB1B. The transcriptional co-activators YAP1 and TAZ are the downstream effectors of the Hippo pathway and regulate target gene expression. Hippo signalling has crucial roles in the control of organ size, tissue homeostasis and regeneration, and dysregulation of the Hippo pathway can lead to uncontrolled cell growth and malignant transformation. Mammalian intestine consists of a stem cell compartment as well as differentiated cells, and its ability to regenerate rapidly after injury makes it an excellent model system to study tissue homeostasis, regeneration and tumorigenesis. Several studies have established the important role of the Hippo pathway in these processes. In addition, crosstalk between Hippo and other signalling pathways provides tight, yet versatile, regulation of tissue homeostasis. In this Review, we summarize studies on the role of the Hippo pathway in the intestine on these physiological processes and the underlying mechanisms responsible, and discuss future research directions and potential therapeutic strategies targeting Hippo signalling in intestinal disease. PMID:27147489

Bilayered, non-cross-linked collagen matrix for regeneration of facial defects after skin cancer removal: a new perspective for biomaterial-based tissue reconstruction.

PubMed

Ghanaati, Shahram; Kovács, Adorján; Barbeck, Mike; Lorenz, Jonas; Teiler, Anna; Sadeghi, Nader; Kirkpatrick, Charles James; Sader, Robert

2016-03-01

Classically skin defects are covered by split thickness skin grafts or by means of local or regional skin flaps. In the presented case series for the first time a bilayered, non-crossed-linked collagen matrix has been used in an off-label fashion in order to reconstruct facial skin defects following different types of skin cancer resection. The material is of porcine origin and consists of a spongy and a compact layer. The ratio of the two layers is 1:3 in favour of the spongy layer. The aim of the study was to investigate the potential of this matrix for skin regeneration as an alternative to the standard techniques of skin grafts or flaps. Six patients between 39 and 83 years old were included in the study based on a therapeutic trial. The collagen matrix was used in seven defects involving the nose, eyelid, forehead- and posterior scalp regions, and ranging from 1,2 to 6 cm in diameter. Two different head and neck surgeons at two different institutions performed the operations. Each used a different technique in covering the wound following surgery, i.e. with and without a latex-based sheet under the pressure dressing. In three cases cylindrical biopsies were taken after 14 days. In all cases the biomaterial application was performed without any complication and no adverse effects were observed. Clinically, the collagen matrix contributed to a tension-free skin regeneration, independent of the wound dressing used. The newly regenerated skin showed strong similarity to the adjacent normal tissue both in quality and colour. Histological analysis indicated that the spongy layer replaced the defective connective tissue, by providing stepwise integration into the surrounding implantation bed, while the compact layer was infiltrated by mononuclear cells and contributed to its epithelialization by means of a "conductive"process from the surrounding epithelial cells. The clinical and histological data demonstrate that the collagen bilayered matrix used in this series contributes to a "Guided-Integrative-Regeneration-Process", which still needs to be further understood. The biomimetic nature of this material seems to contribute to physiological matrix remodelling, which probably involves other matricellular proteins essential for soft tissue regeneration. A deeper understanding of the mechanism, involved in the tissue integration of this material and its contribution to soft tissue regeneration based on the direct and indirect effect of matricellular proteins could open new therapeutic avenues for biomaterial-based soft tissue regeneration as an alternative to traditional flap-based plastic surgery.

Macrophages in injured skeletal muscle: a perpetuum mobile causing and limiting fibrosis, prompting or restricting resolution and regeneration.

PubMed

Bosurgi, Lidia; Manfredi, Angelo A; Rovere-Querini, Patrizia

2011-01-01

Macrophages are present in regenerating skeletal muscles and participate in the repair process. This is due to a unique feature of macrophages, i.e., their ability to perceive signals heralding ongoing tissue injury and to broadcast the news to cells suited at regenerating the tissue such as stem and progenitor cells. Macrophages play a complex role in the skeletal muscle, probably conveying information on the pattern of healing which is appropriate to ensure an effective healing of the tissue, yielding novel functional fibers. Conversely, they are likely to be involved in limiting the efficacy of regeneration, with formation of fibrotic scars and fat replacement of the tissue when the original insult persists. In this review we consider the beneficial versus the detrimental actions of macrophages during the response to muscle injury, with attention to the available information on the molecular code macrophages rely on to guide, throughout the various phases of muscle healing, the function of conventional and unconventional stem cells. Decrypting this code would represent a major step forward toward the establishment of novel targeted therapies for muscle diseases.

Challenges of stem cell-based pulp and dentin regeneration: a clinical perspective.

PubMed

Huang, George T-J; Al-Habib, Mey; Gauthier, Philippe

2013-03-01

There are two types of approaches to regenerate tissues: cell-based and cell-free. The former approach is to introduce exogenous cells into the host to regenerate tissues, and the latter is to use materials other than cells in an attempt to regenerate tissues. There has been a significant advancement in stem cell-based pulp and dentin regeneration research in the past few years. Studies in small and large animals have demonstrated that pulp/dentin-like tissues can be regenerated partially or completely in the root canal space with apical openings of 0.7-3.0 mm using dental pulp stem cells, including stem cells from apical papilla (SCAP) and subpopulations of pulp stem cells. Bone marrow mesenchymal stem cells (BMMSCs) and adipose tissue-derived MSCs (ADMSCs) have also been shown to regenerate pulp-like tissue. In contrast, the cell-free approach has not produced convincing evidence on pulp regeneration. However, one crucial concept has not been considered nor defined in the field of pulp/dentin regeneration and that is the critical size defect of dentin and pulp. Without such consideration and definition, it is difficult to predict or anticipate the extent of cell-free pulp regeneration that would occur. By reasoning, cell-free therapy is unlikely to regenerate an organ/tissue after total loss. Similarly, after a total loss of pulp, it is unlikely to regenerate without using exogenously introduced cells. A cell homing approach may provide a limited amount of tissue regeneration. Although stem cell-based pulp/dentin regeneration has shown great promise, clinical trials are difficult to launch at present. This article will address several issues that challenge and hinder the clinical applications of pulp/dentin regeneration which need to be overcome before stem cell-based pulp/dentin regeneration can occur in the clinic.

Challenges of stem cell-based pulp and dentin regeneration: a clinical perspective

PubMed Central

HUANG, GEORGE T.-J.; AL-HABIB, MEY; GAUTHIER, PHILIPPE

2013-01-01

There are two types of approaches to regenerate tissues: cell-based and cell-free. The former approach is to introduce exogenous cells into the host to regenerate tissues, and the latter is to use materials other than cells in an attempt to regenerate tissues. There has been a significant advancement in stem cell-based pulp and dentin regeneration research in the past few years. Studies in small and large animals have demonstrated that pulp/dentin-like tissues can be regenerated partially or completely in the root canal space with apical openings of 0.7-3.0 mm using dental pulp stem cells, including stem cells from apical papilla (SCAP) and subpopulations of pulp stem cells. Bone marrow mesenchymal stem cells (BMMSCs) and adipose tissue-derived MSCs (ADMSCs) have also been shown to regenerate pulp-like tissue. In contrast, the cell-free approach has not produced convincing evidence on pulp regeneration. However, one crucial concept has not been considered nor defined in the field of pulp/dentin regeneration and that is the critical size defect of dentin and pulp. Without such consideration and definition, it is difficult to predict or anticipate the extent of cell-free pulp regeneration that would occur. By reasoning, cell-free therapy is unlikely to regenerate an organ/tissue after total loss. Similarly, after a total loss of pulp, it is unlikely to regenerate without using exogenously introduced cells. A cell homing approach may provide a limited amount of tissue regeneration. Although stem cell-based pulp/dentin regeneration has shown great promise, clinical trials are difficult to launch at present. This article will address several issues that challenge and hinder the clinical applications of pulp/dentin regeneration which need to be overcome before stem cell-based pulp/dentin regeneration can occur in the clinic. PMID:23914150

Morphogenetic changes occurring in the regenerating newt tail under changed gravity conditions

NASA Astrophysics Data System (ADS)

Radugina, Elena A.; Grigoryan, Eleonora N.; Dvorochkin, Natasha; Almeida, Eduardo

2012-07-01

It is widely accepted that gravity greatly affects animal physiology, development, and alters gene expression. Recently it became apparent that it can also affect tissue morphogenesis. In our work, we developed special laboratory conditions that allow us to produce the gravity-dependent alterations in tail regenerates of the newt Pleurodeles waltl. We examined the dynamic morphogenetic changes during 50-day tail regeneration using computer morphometric analysis. Changes that we observed under these conditions were comparable with those found earlier in our spaceflight experiments. The newts kept in aquarium deep water (low g) after 1/3 tail amputation developed normal lanceolate regenerates. In contrast, the animals that stayed on the moist mat (1g) developed tail regenerates curved ventrally, with tips almost touching the mat. The similar results were obtained with a 12-day centrifugation at 2g. The study of the regenerate morphology in low g, 1g, and 2g animal groups allowed us to determine the stage at which the morphological changes in regenerates become apparent, and to detect the main morphological events associated with the development of tail curve, such as bending of ependymal tube and reorientation of the forming cartilage. We describe cellular processes foregoing observed tissue morphogenetic changes, such as cell migration, condensation in cell population, and unequal proliferation in different areas of epidermis and blastema. Cell proliferation in epidermis and blastema of tails regenerated under the conditions of different gravitational load was evaluated by BrdU assay. In 1g newts, cell proliferation increased within the dorso-apical region of the regenerates compared with that in low g group. These results provide us with a valuable insight into the regenerative tissue homostasis that involves cell division, cell death, and migration in the newt regenerating tail. In addition, these findings could provide us with better understanding of the mechanisms mediating morphogenetic response of regenerating tissues to the modified gravity vector.

Role of the immune system in regeneration and its dynamic interplay with adult stem cells.

PubMed

Abnave, Prasad; Ghigo, Eric

2018-04-09

The immune system plays an indispensable role in the process of tissue regeneration following damage as well as during homeostasis. Inflammation and immune cell recruitment are signs of early onset injury. At the wound site, immune cells not only help to clear debris but also secrete numerous signalling molecules that induce appropriate cell proliferation and differentiation programmes essential for successful regeneration. However, the immune system does not always perform a complementary role in regeneration and several reports have suggested that increased inflammation can inhibit the regeneration process. Successful regeneration requires a balanced immune cell response, with the recruitment of accurately polarised immune cells in an appropriate quantity. The regulatory interactions of the immune system with regeneration are not unidirectional. Stem cells, as key players in regeneration, can also modulate the immune system in several ways to facilitate regeneration. In this review, we will focus on recent research demonstrating the key role of immune system in the regeneration process as well as the immunomodulatory effects of stem cells. Finally, we propose that research investigating the interplay between the immune system and stem cells within highly regenerating animals can benefit the identification of the key interactions and molecules required for successful regeneration. Copyright © 2018 Elsevier Ltd. All rights reserved.

Intermediate Filaments and the Regulation of Cell Motility during Regeneration and Wound Healing.

PubMed

Cheng, Fang; Eriksson, John E

2017-09-01

SUMMARYIntermediate filaments (IFs) comprise a diverse group of flexible cytoskeletal structures, the assembly, dynamics, and functions of which are regulated by posttranslational modifications. Characteristically, the expression of IF proteins is specific for tissues, differentiation stages, cell types, and functional contexts. Recent research has rapidly expanded the knowledge of IF protein functions. From being regarded as primarily structural proteins, it is now well established that IFs act as powerful modulators of cell motility and migration, playing crucial roles in wound healing and tissue regeneration, as well as inflammatory and immune responses. Although many of these IF-associated functions are essential for tissue repair, the involvement of IF proteins has been established in many additional facets of tissue healing and regeneration. Here, we review the recent progress in understanding the multiple functions of cytoplasmic IFs that relate to cell motility in the context of wound healing, taking examples from studies on keratin, vimentin, and nestin. Wound healing and regeneration include orchestration of a broad range of cellular processes, including regulation of cell attachment and migration, proliferation, differentiation, immune responses, angiogenesis, and remodeling of the extracellular matrix. In this respect, IF proteins now emerge as multifactorial and tissue-specific integrators of tissue regeneration, thereby acting as essential guardian biopolymers at the interface between health and disease, the failing of which contributes to a diverse range of pathologies. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

Guided genetic screen to identify genes essential in the regeneration of hair cells and other tissues.

PubMed

Pei, Wuhong; Xu, Lisha; Huang, Sunny C; Pettie, Kade; Idol, Jennifer; Rissone, Alberto; Jimenez, Erin; Sinclair, Jason W; Slevin, Claire; Varshney, Gaurav K; Jones, MaryPat; Carrington, Blake; Bishop, Kevin; Huang, Haigen; Sood, Raman; Lin, Shuo; Burgess, Shawn M

2018-01-01

Regenerative medicine holds great promise for both degenerative diseases and traumatic tissue injury which represent significant challenges to the health care system. Hearing loss, which affects hundreds of millions of people worldwide, is caused primarily by a permanent loss of the mechanosensory receptors of the inner ear known as hair cells. This failure to regenerate hair cells after loss is limited to mammals, while all other non-mammalian vertebrates tested were able to completely regenerate these mechanosensory receptors after injury. To understand the mechanism of hair cell regeneration and its association with regeneration of other tissues, we performed a guided mutagenesis screen using zebrafish lateral line hair cells as a screening platform to identify genes that are essential for hair cell regeneration, and further investigated how genes essential for hair cell regeneration were involved in the regeneration of other tissues. We created genetic mutations either by retroviral insertion or CRISPR/Cas9 approaches, and developed a high-throughput screening pipeline for analyzing hair cell development and regeneration. We screened 254 gene mutations and identified 7 genes specifically affecting hair cell regeneration. These hair cell regeneration genes fell into distinct and somewhat surprising functional categories. By examining the regeneration of caudal fin and liver, we found these hair cell regeneration genes often also affected other types of tissue regeneration. Therefore, our results demonstrate guided screening is an effective approach to discover regeneration candidates, and hair cell regeneration is associated with other tissue regeneration.

Modulation of tissue repair by regeneration enhancer elements.

PubMed

Kang, Junsu; Hu, Jianxin; Karra, Ravi; Dickson, Amy L; Tornini, Valerie A; Nachtrab, Gregory; Gemberling, Matthew; Goldman, Joseph A; Black, Brian L; Poss, Kenneth D

2016-04-14

How tissue regeneration programs are triggered by injury has received limited research attention. Here we investigate the existence of enhancer regulatory elements that are activated in regenerating tissue. Transcriptomic analyses reveal that leptin b (lepb) is highly induced in regenerating hearts and fins of zebrafish. Epigenetic profiling identified a short DNA sequence element upstream and distal to lepb that acquires open chromatin marks during regeneration and enables injury-dependent expression from minimal promoters. This element could activate expression in injured neonatal mouse tissues and was divisible into tissue-specific modules sufficient for expression in regenerating zebrafish fins or hearts. Simple enhancer-effector transgenes employing lepb-linked sequences upstream of pro- or anti-regenerative factors controlled the efficacy of regeneration in zebrafish. Our findings provide evidence for 'tissue regeneration enhancer elements' (TREEs) that trigger gene expression in injury sites and can be engineered to modulate the regenerative potential of vertebrate organs.

Epoxyeicosanoids promote organ and tissue regeneration.

PubMed

Panigrahy, Dipak; Kalish, Brian T; Huang, Sui; Bielenberg, Diane R; Le, Hau D; Yang, Jun; Edin, Matthew L; Lee, Craig R; Benny, Ofra; Mudge, Dayna K; Butterfield, Catherine E; Mammoto, Akiko; Mammoto, Tadanori; Inceoglu, Bora; Jenkins, Roger L; Simpson, Mary A; Akino, Tomoshige; Lih, Fred B; Tomer, Kenneth B; Ingber, Donald E; Hammock, Bruce D; Falck, John R; Manthati, Vijaya L; Kaipainen, Arja; D'Amore, Patricia A; Puder, Mark; Zeldin, Darryl C; Kieran, Mark W

2013-08-13

Epoxyeicosatrienoic acids (EETs), lipid mediators produced by cytochrome P450 epoxygenases, regulate inflammation, angiogenesis, and vascular tone. Despite pleiotropic effects on cells, the role of these epoxyeicosanoids in normal organ and tissue regeneration remains unknown. EETs are produced predominantly in the endothelium. Normal organ and tissue regeneration require an active paracrine role of the microvascular endothelium, which in turn depends on angiogenic growth factors. Thus, we hypothesize that endothelial cells stimulate organ and tissue regeneration via production of bioactive EETs. To determine whether endothelial-derived EETs affect physiologic tissue growth in vivo, we used genetic and pharmacological tools to manipulate endogenous EET levels. We show that endothelial-derived EETs play a critical role in accelerating tissue growth in vivo, including liver regeneration, kidney compensatory growth, lung compensatory growth, wound healing, corneal neovascularization, and retinal vascularization. Administration of synthetic EETs recapitulated these results, whereas lowering EET levels, either genetically or pharmacologically, delayed tissue regeneration, demonstrating that pharmacological modulation of EETs can affect normal organ and tissue growth. We also show that soluble epoxide hydrolase inhibitors, which elevate endogenous EET levels, promote liver and lung regeneration. Thus, our observations indicate a central role for EETs in organ and tissue regeneration and their contribution to tissue homeostasis.

Co-culture systems-based strategies for articular cartilage tissue engineering.

PubMed

Zhang, Yu; Guo, Weimin; Wang, Mingjie; Hao, Chunxiang; Lu, Liang; Gao, Shuang; Zhang, Xueliang; Li, Xu; Chen, Mingxue; Li, Penghao; Jiang, Peng; Lu, Shibi; Liu, Shuyun; Guo, Quanyi

2018-03-01

Cartilage engineering facilitates repair and regeneration of damaged cartilage using engineered tissue that restores the functional properties of the impaired joint. The seed cells used most frequently in tissue engineering, are chondrocytes and mesenchymal stem cells. Seed cells activity plays a key role in the regeneration of functional cartilage tissue. However, seed cells undergo undesirable changes after in vitro processing procedures, such as degeneration of cartilage cells and induced hypertrophy of mesenchymal stem cells, which hinder cartilage tissue engineering. Compared to monoculture, which does not mimic the in vivo cellular environment, co-culture technology provides a more realistic microenvironment in terms of various physical, chemical, and biological factors. Co-culture technology is used in cartilage tissue engineering to overcome obstacles related to the degeneration of seed cells, and shows promise for cartilage regeneration and repair. In this review, we focus first on existing co-culture systems for cartilage tissue engineering and related fields, and discuss the conditions and mechanisms thereof. This is followed by methods for optimizing seed cell co-culture conditions to generate functional neo-cartilage tissue, which will lead to a new era in cartilage tissue engineering. © 2017 Wiley Periodicals, Inc.

Expression of nestin and chromogranin in regeneration zones of rat pancreas.

PubMed

Ege, Bahadir; Dinc, Tolga; Kayilioglu, Selami Ilgaz; Tezel, Ekmel; Ersoy, Emin

2017-01-01

The particular signals that start and orchestrate the regeneration process in pancreas are not well understood yet. We aimed to investigate the expression of nestin and chromogranin A in pancreatic regeneration zones and a secondary objective, we assessed the efficiency of pancreatic duct ligation method in creation of a pancreatic regeneration model in rats. Partial (90%) pancreatectomy and pancreatic duct ligation were performed in Wistar rats, in order to create pancreatic regeneration models. Pancreatic tissues were examined histologically. Expression profiles were investigated by immunohistochemistry for nestin and chromogranin A. Nestin and chromogranin A expressions were observed in regeneration zones. Pancreatic regenerations zones were seen in pancreatic duct ligation group samples as well as partial pancreatectomy group. Nestin was expressed prominently in acinoductular metaplasia cells in regeneration zones. This was best demonstrated in the samples of pancreatic duct ligation group. In the subsequent sections of nestin positive sites, cytoplasmic positivity with chromogranin A was observed. This study confirms that nestin and chromogranin A can be detected in neogenesis-evoked pancreatic tissue, particularly in the acinoductular epithelium. Nestin and chromogranin A may be important markers to identify pancreatic stem cells. Pancreatic duct ligation can be used for creating pancreatic regeneration model in rats. Chromogranin A, Nestin, Pancreas, Regeneration, Stem cells.

Regeneration of gingival tissue using in situ tissue engineering with collagen scaffold.

PubMed

Hatayama, Takahide; Nakada, Akira; Nakamura, Hiroki; Mariko, Wakatsuki; Tsujimoto, Gentarou; Nakamura, Tatsuo

2017-10-01

The aim of the study was to evaluate 2 types of collagen scaffold for gingival regeneration. Two types of collagen scaffolds, CS-pH7.4 and CS-pH3.0, were prepared by processing atelocollagen at pH 7.4 or 3.0, respectively, followed by dehydrothermal treatment. Gingival wounds with sizes of 4 × 6 mm (rectangle) or 6 mm diameter (circle) were made with buccal incisions in beagle dogs. The defective area was surgically covered with the CS-pH7.4, CS-pH3.0, or no scaffold (control). Gingival regeneration was assessed by monitoring the differences in the lengths of the epithelial and submucosal tissues at the wound site and the normal site. Histopathologic assessments were performed by 4 evaluators independently; statistical significance was evaluated by using the Wald test. Significantly higher recovery of epithelial and submucosal tissues, which, in turn, resulted in recovery of gum thickness, was observed in gingival wounds treated with the CS-pH7.4 compared with that in the control. CS-pH3.0 treatment also resulted in higher gingival regeneration compared with the control; however, the effects were more pronounced in wounds treated with the CS-pH7.4. CS-pH7.4-treated wounds showed better gingival regeneration compared with the control and CS-pH3.0-treated wounds, even after adjusting for interevaluator differences using a linear mixed model. CS-pH7.4 is a promising scaffold for gingival tissue regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Bi-layered collagen nano-structured membrane prototype collagen matrix 10826® for soft tissue regeneration in rabbits: an in vivo ultra-structural study of the early healing phase.

PubMed

De Santis, D; Menchini Fabris, G B; Lotti, J; Palumbo, C; Ferretti, M; Castellani, R; Lotti, T; Zanotti, G; Gelpi, F; Covani, C; Nocini, P F

Collagen Matrix (CM) 10826 is a nanostructured bi-layered collagen membrane obtained from type I and III porcine collagen, which in vitro has shown to have the potential to be a substitute and/or stimulant for soft oral tissue regeneration. The objective of this study was to evaluate the in vivo potential and safety of this membrane for soft tissue regeneration in the early stage of wound healing. Two soft tissue wounds (test and control) were created on the back skin of 5 rabbits (female New Zealand White Rabbits specific pathogen free). All wounds were protected by a special poly-tetra-fluoro-ethylene (PTFE) healing camera. On each rabbit on the test side CM-10826 was used, while on the control side conventional treatment (an autologous pedicle graft) was performed. The healing process was observed clinically after 2 and 6 days, and Magnetic Resonance Imaging (MRI) was performed after this period. After 7 days, animals were sacrificed and specimens were analyzed with light optic microscopy (LM), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). These in vivo trials on rabbits confirmed that CM-10826 is well tolerated, without signs of histological inflammatory reaction and proved to be able to accelerate the spontaneous repair of the skin defect taken as the control. The light-optic and ultra-microscopy of serial biopsies showed that the new matrix is biocompatible and is able to function as a scaffold inducing soft tissue regeneration. In conclusion this study demonstrates that CM-10826 promote early soft tissue regeneration and suggests it is a potential constituent for human autologous keratinocytes seeded derma bioequivalent. It protects the wound from injuries and bacterial contamination accelerating healing process. As a clinical relevance, we consider that the quality of life of patients will be improved avoiding the use of major autologous grafts, reducing the hospitalization time and morbidity.

In situ macrophage phenotypic transition is affected by altered cellular composition prior to acute sterile muscle injury.

PubMed

Patsalos, Andreas; Pap, Attila; Varga, Tamas; Trencsenyi, Gyorgy; Contreras, Gerardo Alvarado; Garai, Ildiko; Papp, Zoltan; Dezso, Balazs; Pintye, Eva; Nagy, Laszlo

2017-09-01

The in situ phenotypic switch of macrophages is delayed in acute injury following irradiation. The combination of bone marrow transplantation and local muscle radiation protection allows for the identification of a myeloid cell contribution to tissue repair. PET-MRI allows monitoring of myeloid cell invasion and metabolism. Altered cellular composition prior to acute sterile injury affects the in situ phenotypic transition of invading myeloid cells to repair macrophages. There is reciprocal intercellular communication between local muscle cell compartments, such as PAX7 positive cells, and recruited macrophages during skeletal muscle regeneration. Skeletal muscle regeneration is a complex interplay between various cell types including invading macrophages. Their recruitment to damaged tissues upon acute sterile injuries is necessary for clearance of necrotic debris and for coordination of tissue regeneration. This highly dynamic process is characterized by an in situ transition of infiltrating monocytes from an inflammatory (Ly6C high ) to a repair (Ly6C low ) macrophage phenotype. The importance of the macrophage phenotypic shift and the cross-talk of the local muscle tissue with the infiltrating macrophages during tissue regeneration upon injury are not fully understood and their study lacks adequate methodology. Here, using an acute sterile skeletal muscle injury model combined with irradiation, bone marrow transplantation and in vivo imaging, we show that preserved muscle integrity and cell composition prior to the injury is necessary for the repair macrophage phenotypic transition and subsequently for proper and complete tissue regeneration. Importantly, by using a model of in vivo ablation of PAX7 positive cells, we show that this radiosensitive skeletal muscle progenitor pool contributes to macrophage phenotypic transition following acute sterile muscle injury. In addition, local muscle tissue radioprotection by lead shielding during irradiation preserves normal macrophage transition dynamics and subsequently muscle tissue regeneration. Taken together, our data suggest the existence of a more extensive and reciprocal cross-talk between muscle tissue compartments, including satellite cells, and infiltrating myeloid cells upon tissue damage. These interactions shape the macrophage in situ phenotypic shift, which is indispensable for normal muscle tissue repair dynamics. © 2017 The Authors. The Journal of Physiology © 2017 The Physiological Society.

Peptide-Based Materials for Cartilage Tissue Regeneration.

PubMed

Hastar, Nurcan; Arslan, Elif; Guler, Mustafa O; Tekinay, Ayse B

2017-01-01

Cartilaginous tissue requires structural and metabolic support after traumatic or chronic injuries because of its limited capacity for regeneration. However, current techniques for cartilage regeneration are either invasive or ineffective for long-term repair. Developing alternative approaches to regenerate cartilage tissue is needed. Therefore, versatile scaffolds formed by biomaterials are promising tools for cartilage regeneration. Bioactive scaffolds further enhance the utility in a broad range of applications including the treatment of major cartilage defects. This chapter provides an overview of cartilage tissue, tissue defects, and the methods used for regeneration, with emphasis on peptide scaffold materials that can be used to supplement or replace current medical treatment options.

Morpho-histology and genotype dependence of in vitro morphogenesis in mature embryo cultures of wheat.

PubMed

Delporte, Fabienne; Pretova, Anna; du Jardin, Patrick; Watillon, Bernard

2014-11-01

Cellular totipotency is one of the basic principles of plant biotechnology. Currently, the success of the procedure used to produce transgenic plants is directly proportional to the successful insertion of foreign DNA into the genome of suitable target tissue/cells that are able to regenerate plants. The mature embryo (ME) is increasingly recognized as a valuable explant for developing regenerable cell lines in wheat biotechnology. We have previously developed a regeneration procedure based on fragmented ME in vitro culture. Before we can use this regeneration system as a model for molecular studies of the morphogenic pathway induced in vitro and investigate the functional links between regenerative capacity and transformation receptiveness, some questions need to be answered. Plant regeneration from cultured tissues is genetically controlled. Factors such as age/degree of differentiation and physiological conditions affect the response of explants to culture conditions. Plant regeneration in culture can be achieved through embryogenesis or organogenesis. In this paper, the suitability of ME tissues for tissue culture and the chronological series of morphological data observed at the macroscopic level are documented. Genetic variability at each step of the regeneration process was evaluated through a varietal comparison of several elite wheat cultivars. A detailed histological analysis of the chronological sequence of morphological events during ontogeny was conducted. Compared with cultures of immature zygotic embryos, we found that the embryogenic pathway occurs slightly earlier and is of a different origin in our model. Cytological, physiological, and some biochemical aspects of somatic embryo formation in wheat ME culture are discussed.

Engineering Bi-Layer Nanofibrous Conduits for Peripheral Nerve Regeneration

PubMed Central

Zhu, Yiqian; Wang, Aijun; Patel, Shyam; Kurpinski, Kyle; Diao, Edward; Bao, Xuan; Kwong, George; Young, William L.

2011-01-01

Trauma injuries often cause peripheral nerve damage and disability. A goal in neural tissue engineering is to develop synthetic nerve conduits for peripheral nerve regeneration having therapeutic efficacy comparable to that of autografts. Nanofibrous conduits with aligned nanofibers have been shown to promote nerve regeneration, but current fabrication methods rely on rolling a fibrous sheet into the shape of a conduit, which results in a graft with inconsistent size and a discontinuous joint or seam. In addition, the long-term effects of nanofibrous nerve conduits, in comparison with autografts, are still unknown. Here we developed a novel one-step electrospinning process and, for the first time, fabricated a seamless bi-layer nanofibrous nerve conduit: the luminal layer having longitudinally aligned nanofibers to promote nerve regeneration, and the outer layer having randomly organized nanofibers for mechanical support. Long-term in vivo studies demonstrated that bi-layer aligned nanofibrous nerve conduits were superior to random nanofibrous conduits and had comparable therapeutic effects to autografts for nerve regeneration. In summary, we showed that the engineered nanostructure had a significant impact on neural tissue regeneration in situ. The results from this study will also lead to the scalable fabrication of engineered nanofibrous nerve conduits with designed nanostructure. This technology platform can be combined with drug delivery and cell therapies for tissue engineering. PMID:21501089

Effect of Glycine, Pyruvate, and Resveratrol on the Regeneration Process of Postischemic Intestinal Mucosa

PubMed Central

Brencher, Lisa; Petrat, Frank; Stych, Katrin; Hamburger, Tim

2017-01-01

Background Intestinal ischemia is often caused by a malperfusion of the upper mesenteric artery. Since the intestinal mucosa is one of the most rapidly proliferating organs in human body, this tissue can partly regenerate itself after the onset of ischemia and reperfusion (I/R). Therefore, we investigated whether glycine, sodium pyruvate, and resveratrol can either support or potentially harm regeneration when applied therapeutically after reperfusion injury. Methods I/R of the small intestine was initiated by occluding and reopening the upper mesenteric artery in rats. After 60 min of ischemia and 300 min of reperfusion, glycine, sodium pyruvate, or resveratrol was administered intravenously. Small intestine regeneration was analyzed regarding tissue damage, activity of saccharase, and Ki-67 positive cells. Additionally, systemic parameters and metabolic ones were obtained at selected periods. Results Resveratrol failed in improving the outcome after I/R, while glycine showed a partial beneficial effect. Sodium pyruvate ameliorated metabolic acidosis, diminished histopathologic tissue injury, and increased cell proliferation in the small intestine. Conclusion While glycine could improve in part regeneration but not proliferation, sodium pyruvate seems to be a possible therapeutic agent to facilitate proliferation and to support mucosal regeneration after I/R injury to the small intestine. PMID:29201896

Stem cells applications in bone and tooth repair and regeneration: New insights, tools, and hopes.

PubMed

Abdel Meguid, Eiman; Ke, Yuehai; Ji, Junfeng; El-Hashash, Ahmed H K

2018-03-01

The exploration of stem and progenitor cells holds promise for advancing our understanding of the biology of tissue repair and regeneration mechanisms after injury. This will also help in the future use of stem cell therapy for the development of regenerative medicine approaches for the treatment of different tissue-species defects or disorders such as bone, cartilages, and tooth defects or disorders. Bone is a specialized connective tissue, with mineralized extracellular components that provide bones with both strength and rigidity, and thus enable bones to function in body mechanical supports and necessary locomotion process. New insights have been added to the use of different types of stem cells in bone and tooth defects over the last few years. In this concise review, we briefly describe bone structure as well as summarize recent research progress and accumulated information regarding the osteogenic differentiation of stem cells, as well as stem cell contributions to bone repair/regeneration, bone defects or disorders, and both restoration and regeneration of bones and cartilages. We also discuss advances in the osteogenic differentiation and bone regeneration of dental and periodontal stem cells as well as in stem cell contributions to dentine regeneration and tooth engineering. © 2017 Wiley Periodicals, Inc.

Fluctuations and differential contraction during regeneration of Hydra vulgaris tissue toroids

NASA Astrophysics Data System (ADS)

Krahe, Michael; Wenzel, Iris; Lin, Kao-Nung; Fischer, Julia; Goldmann, Joseph; Kästner, Markus; Fütterer, Claus

2013-03-01

We studied regenerating bilayered tissue toroids dissected from Hydra vulgaris polyps and relate our macroscopic observations to the dynamics of force-generating mesoscopic cytoskeletal structures. Tissue fragments undergo a specific toroid-spheroid folding process leading to complete regeneration towards a new organism. The time scale of folding is too fast for biochemical signalling or morphogenetic gradients, which forced us to assume purely mechanical self-organization. The initial pattern selection dynamics was studied by embedding toroids into hydro-gels, allowing us to observe the deformation modes over longer periods of time. We found increasing mechanical fluctuations which break the toroidal symmetry, and discuss the evolution of their power spectra for various gel stiffnesses. Our observations are related to single-cell studies which explain the mechanical feasibility of the folding process. In addition, we observed switching of cells from a tissue bound to a migrating state after folding failure as well as in tissue injury. We found a supra-cellular actin ring assembled along the toroid's inner edge. Its contraction can lead to the observed folding dynamics as we could confirm by finite element simulations. This actin ring in the inner cell layer is assembled by myosin-driven length fluctuations of supra-cellular F-actin bundles (myonemes) in the outer cell layer. This paper is dedicated to Malcolm Steinberg.

Use of fibroblast growth factor 2 for expansion of chondrocytes and tissue engineering

NASA Technical Reports Server (NTRS)

Vunjak-Novakovic, Gordana (Inventor); Martin, Ivan (Inventor); Freed, Lisa E. (Inventor); Langer, Robert (Inventor)

2003-01-01

The present invention provides an improved method for expanding cells for use in tissue engineering. In particular the method provides specific biochemical factors to supplement cell culture medium during the expansion process in order to reproduce events occurring during embryonic development with the goal of regenerating tissue equivalents that resemble natural tissues both structurally and functionally. These specific biochemical factors improve proliferation of the cells and are capable of de-differentiation mature cells isolated from tissue so that the differentiation potential of the cells is preserved. The bioactive molecules also maintain the responsiveness of the cells to other bioactive molecules. Specifically, the invention provides methods for expanding chondrocytes in the presence of fibroblast growth factor 2 for use in regeneration of cartilage tissue.

Adipose-derived stem cells and periodontal tissue engineering.

PubMed

Tobita, Morikuni; Mizuno, Hiroshi

2013-01-01

Innovative developments in the multidisciplinary field of tissue engineering have yielded various implementation strategies and the possibility of functional tissue regeneration. Technologic advances in the combination of stem cells, biomaterials, and growth factors have created unique opportunities to fabricate tissues in vivo and in vitro. The therapeutic potential of human multipotent mesenchymal stem cells (MSCs), which are harvested from bone marrow and adipose tissue, has generated increasing interest in a wide variety of biomedical disciplines. These cells can differentiate into a variety of tissue types, including bone, cartilage, fat, and nerve tissue. Adipose-derived stem cells have some advantages compared with other sources of stem cells, most notably that a large number of cells can be easily and quickly isolated from adipose tissue. In current clinical therapy for periodontal tissue regeneration, several methods have been developed and applied either alone or in combination, such as enamel matrix proteins, guided tissue regeneration, autologous/allogeneic/xenogeneic bone grafts, and growth factors. However, there are various limitations and shortcomings for periodontal tissue regeneration using current methods. Recently, periodontal tissue regeneration using MSCs has been examined in some animal models. This method has potential in the regeneration of functional periodontal tissues because the various secreted growth factors from MSCs might not only promote the regeneration of periodontal tissue but also encourage neovascularization of the damaged tissues. Adipose-derived stem cells are especially effective for neovascularization compared with other MSC sources. In this review, the possibility and potential of adipose-derived stem cells for regenerative medicine are introduced. Of particular interest, periodontal tissue regeneration with adipose-derived stem cells is discussed.

A diffusible signal derived from hematopoietic cells supports the survival and proliferation of regenerative cells during zebrafish fin fold regeneration.

PubMed

Hasegawa, Tomoya; Nakajima, Teruhiro; Ishida, Takashi; Kudo, Akira; Kawakami, Atsushi

2015-03-01

Multicellular organisms maintain body integrity by constantly regenerating tissues throughout their lives; however, the overall mechanism for regulating regeneration remains an open question. Studies of limb and fin regeneration in teleost fish and urodeles have shown the involvement of a number of locally activated signals at the wounded site during regeneration. Here, we demonstrate that a diffusible signal from a distance also play an essential role for regeneration. Among a number of zebrafish mutants, we found that the zebrafish cloche (clo) and tal1 mutants, which lack most hematopoietic tissues, displayed a unique regeneration defect accompanying apoptosis in primed regenerative tissue. Our analyses of the mutants showed that the cells in the primed regenerative tissue are susceptible to apoptosis, but their survival is normally supported by the presence of hematopoietic tissues, mainly the myeloid cells. We further showed that a diffusible factor in the wild-type body fluid mediates this signal. Thus, our study revealed a novel mechanism that the hematopoietic tissues regulate tissue regeneration through a diffusible signal. Copyright © 2014 Elsevier Inc. All rights reserved.

Fabrication and Biocompatibility of Electrospun Silk Biocomposites

PubMed Central

Wei, Kai; Kim, Byoung-Suhk; Kim, Ick-Soo

2011-01-01

Silk fibroin has attracted great interest in tissue engineering because of its outstanding biocompatibility, biodegradability and minimal inflammatory reaction. In this study, two kinds of biocomposites based on regenerated silk fibroin are fabricated by electrospinning and post-treatment processes, respectively. Firstly, regenerated silk fibroin/tetramethoxysilane (TMOS) hybrid nanofibers with high hydrophilicity are prepared, which is superior for fibroblast attachment. The electrospinning process causes adjacent fibers to ‘weld’ at contact points, which can be proved by scanning electron microscope (SEM). The water contact angle of silk/tetramethoxysilane (TMOS) composites shows a sharper decrease than pure regenerated silk fibroin nanofiber, which has a great effect on the early stage of cell attachment behavior. Secondly, a novel tissue engineering scaffold material based on electrospun silk fibroin/nano-hydroxyapatite (nHA) biocomposites is prepared by means of an effective calcium and phosphate (Ca–P) alternate soaking method. nHA is successfully produced on regenerated silk fibroin nanofiber within several min without any pre-treatments. The osteoblastic activities of this novel nanofibrous biocomposites are also investigated by employing osteoblastic-like MC3T3-E1 cell line. The cell functionality such as alkaline phosphatase (ALP) activity is ameliorated on mineralized silk nanofibers. All these results indicate that this silk/nHA biocomposite scaffold material may be a promising biomaterial for bone tissue engineering. PMID:24957869

3D bioprinting matrices with controlled pore structure and release function guide in vitro self-organization of sweat gland.

PubMed

Liu, Nanbo; Huang, Sha; Yao, Bin; Xie, Jiangfan; Wu, Xu; Fu, Xiaobing

2016-10-03

3D bioprinting matrices are novel platforms for tissue regeneration. Tissue self-organization is a critical process during regeneration that implies the features of organogenesis. However, it is not clear from the current evidences whether 3D printed construct plays a role in guiding tissue self-organization in vitro. Based on our previous study, we bioprinted a 3D matrix as the restrictive niche for direct sweat gland differentiation of epidermal progenitors by different pore structure (300-μm or 400-μm nozzle diameters printed) and reported a long-term gradual transition of differentiated cells into glandular morphogenesis occurs within the 3D construct in vitro. At the initial 14-day culture, an accelerated cell differentiation was achieved with inductive cues released along with gelatin reduction. After protein release completed, the 3D construct guide the self-organized formation of sweat gland tissues, which is similar to that of the natural developmental process. However, glandular morphogenesis was only observed in 300-μm-printed constructs. In the absence of 3D architectural support, glandular morphogenesis was not occurred. This striking finding made us to identify a previously unknown role of the 3D-printed structure in glandular tissue regeneration, and this self-organizing strategy can be applied to forming other tissues in vitro.

Down-regulate of Djrfc2 causes tissues hypertrophy during planarian regeneration.

PubMed

Guo, Qi; Zhao, Guixia; Ni, Jiajia; Guo, Yanan; Zhang, Yizhe; Tian, Qingnan; Zhang, Shoutao

2017-11-25

Planarians are an ideal model organism for regeneration research due to their amazing ability to regenerate. DNA replication is crucial for genome stability. Replication factor C (RFC), which is a replication factor C-like complex and plays an important role during DNA replication in eukaryotes, has been reported as a wound response factor during planarian regeneration. However, how RFC controls regeneration in planarians by regulating DNA replication remains to be explained. Here, we used a two-dimensional electrophoresis (2-DE) proteomic approach to identify differentially expressed proteins in intact and regenerated planarians. Approximately 132 protein spots showed differences between intact and regenerative tissues. We selected 21 significantly expressed protein spots and processed them using TOF MS analysis. Finally, we cloned three of these candidate genes (Djhsp70, Djrfc2, Djfaim), focusing on the function of Djrfc2 during regeneration. We found that the distribution of Djrfc2 tends toward the wound site. RNA interference (RNAi) of Djrfc2 increases the number of dividing cells and the expression level of planarian neoblast marker genes, which may result in hyper-proliferation. Our studies use an available approach to directly study the regeneration dynamic at the protein level and provide further evidence to support a function of Djrfc2 in planarian regeneration. Copyright © 2017. Published by Elsevier Inc.

Comparative Study of Injury Models for Studying Muscle Regeneration in Mice

PubMed Central

Hardy, David; Besnard, Aurore; Latil, Mathilde; Jouvion, Grégory; Briand, David; Thépenier, Cédric; Pascal, Quentin; Guguin, Aurélie; Gayraud-Morel, Barbara; Cavaillon, Jean-Marc; Tajbakhsh, Shahragim

2016-01-01

Background A longstanding goal in regenerative medicine is to reconstitute functional tissus or organs after injury or disease. Attention has focused on the identification and relative contribution of tissue specific stem cells to the regeneration process. Relatively little is known about how the physiological process is regulated by other tissue constituents. Numerous injury models are used to investigate tissue regeneration, however, these models are often poorly understood. Specifically, for skeletal muscle regeneration several models are reported in the literature, yet the relative impact on muscle physiology and the distinct cells types have not been extensively characterised. Methods We have used transgenic Tg:Pax7nGFP and Flk1GFP/+ mouse models to respectively count the number of muscle stem (satellite) cells (SC) and number/shape of vessels by confocal microscopy. We performed histological and immunostainings to assess the differences in the key regeneration steps. Infiltration of immune cells, chemokines and cytokines production was assessed in vivo by Luminex®. Results We compared the 4 most commonly used injury models i.e. freeze injury (FI), barium chloride (BaCl2), notexin (NTX) and cardiotoxin (CTX). The FI was the most damaging. In this model, up to 96% of the SCs are destroyed with their surrounding environment (basal lamina and vasculature) leaving a “dead zone” devoid of viable cells. The regeneration process itself is fulfilled in all 4 models with virtually no fibrosis 28 days post-injury, except in the FI model. Inflammatory cells return to basal levels in the CTX, BaCl2 but still significantly high 1-month post-injury in the FI and NTX models. Interestingly the number of SC returned to normal only in the FI, 1-month post-injury, with SCs that are still cycling up to 3-months after the induction of the injury in the other models. Conclusions Our studies show that the nature of the injury model should be chosen carefully depending on the experimental design and desired outcome. Although in all models the muscle regenerates completely, the trajectories of the regenerative process vary considerably. Furthermore, we show that histological parameters are not wholly sufficient to declare that regeneration is complete as molecular alterations (e.g. cycling SCs, cytokines) could have a major persistent impact. PMID:26807982

Accelerated In Vitro Degradation of Optically Clear Low β-Sheet Silk Films by Enzyme-Mediated Pretreatment

PubMed Central

Shang, Ke; Rnjak-Kovacina, Jelena; Lin, Yinan; Hayden, Rebecca S.; Tao, Hu; Kaplan, David L.

2013-01-01

Purpose: To design patterned, transparent silk films with fast degradation rates for the purpose of tissue engineering corneal stroma. Methods: β-sheet (crystalline) content of silk films was decreased significantly by using a short water annealing time. Additionally, a protocol combining short water annealing time with enzymatic pretreatment of silk films with protease XIV was developed. Results: Low β-sheet content (17%–18%) and enzymatic pretreatment provided film stability in aqueous environments and accelerated degradation of the silk films in the presence of human corneal fibroblasts in vitro. The results demonstrate a direct relationship between reduced β-sheet content and enzymatic pretreatment, and overall degradation rate of the protein films. Conclusions: The novel protocol developed here provides new approaches to modulate the regeneration rate of silk biomaterials for corneal tissue regeneration needs. Translational Relevance: Patterned silk protein films possess desirable characteristics for corneal tissue engineering, including optical transparency, biocompatibility, cell alignment, and tunable mechanical properties, but current fabrication protocols do not provide adequate degradation rates to match the regeneration properties of the human cornea. This novel processing protocol makes silk films more suitable for the construction of human corneal stroma tissue and a promising way to tune silk film degradation properties to match corneal tissue regeneration. PMID:24049717

Accelerated in vitro Degradation of Optically Clear Low β-sheet Silk Films by Enzyme-Mediated Pretreatment

PubMed Central

Shang, Ke; Rnjak-Kovacina, Jelena; Lin, Yinan; Hayden, Rebecca S.; Hu, Tao; Kaplan, David L.

2013-01-01

Purpose To design patterned, transparent silk films with fast degradation rates for the purpose of tissue engineering corneal stroma, Methods β-sheet (crystalline) content of silk films was decreased significantly by using a short water annealing time. Additionally, a protocol combining short water annealing time with enzymatic pretreatment of silk films with protease XIV was developed. Results Low β-sheet content (17–18%) and enzymatic pre-treatment provided film stability in aqueous environments and accelerated degradation of the silk films in the presence of human corneal fibroblasts in vitro. The results demonstrate a direct relationship between reduced β-sheet content and enzymatic pre-treatment and overall degradation rate of the protein films. Conclusions The novel protocol developed here provides new approaches to modulate the regeneration rate of silk biomaterials for corneal tissue regeneration needs. Translational relevance Patterned silk protein films possess desirable characteristics for corneal tissue engineering, including optical transparency, biocompatibility, cell alignment and tunable mechanical properties, but current fabrication protocols do not provide adequate degradation rates to match the regeneration properties of the human cornea. This novel processing protocol makes silk films more suitable for the construction of human corneal stroma tissue and a promising way to tune silk film degradation properties to match corneal tissue regeneration. PMID:23579493

Transplantation of mature adipocyte-derived dedifferentiated fat cells into three-wall defects in the rat periodontium induces tissue regeneration.

PubMed

Suzuki, Daigo; Akita, Daisuke; Tsurumachi, Niina; Kano, Koichiro; Yamanaka, Katsuyuki; Kaneko, Tadashi; Kawano, Eisuke; Iguchi, Shinya; Toriumi, Taku; Arai, Yoshinori; Matsumoto, Taro; Sato, Shuichi; Honda, Masaki

2017-01-01

The transplantation of dedifferentiated fat (DFAT) cells in combination with poly(d,l-lactic-co-glycolic acid) (PLGA) scaffolds has previously been proven as an effective approach in promoting periodontal tissue regeneration in a rat fenestration defect model. The aim of this study was to assess the regenerative potential of DFAT cells in a rat model of three-wall periodontal bone defect. Three-wall bone defects were created bilaterally on the mesial side of rat maxillary first molars and were either left untreated or treated by implantation of PLGA scaffolds with DFAT cells or PLGA alone. Four weeks after surgery, the tissues were processed for micro-computed tomography (micro-CT) and histomorphometric examination. Micro-CT revealed that the PLGA/DFAT group had significantly higher rates of bone regeneration than the other groups, while histomorphometric analysis showed that the PLGA/DFAT group had significantly higher densities of collagen fiber bundles in acellular and cellular cementum than the PLGA group. Moreover, the results indicate that the placement of the PLGA scaffold prevented the downgrowth of the junctional epithelium. These findings suggest that DFAT cells contribute to tissue regeneration in three-wall periodontal defects, while PLGA provides space necessary for periodontal tissue restoration.

Root cementum may modulate gene expression during periodontal regeneration: a preliminary study in humans.

PubMed

Gonçalves, Patricia F; Lima, Liana L; Sallum, Enilson A; Casati, Márcio Z; Nociti, Francisco H

2008-02-01

Previous data demonstrated that root cementum may affect periodontal regeneration. As such, this study aimed to explore further possible mechanisms involved in this process by investigating in humans whether root cementum modulates gene expression in the regenerating tissue formed under membrane-protected intrabony defects. Thirty subjects with deep intrabony defects (> or =5 mm; 2- or 3-wall) were selected and assigned to the control or test group. The control group received scaling and root planing with the removal of granulation tissue and root cementum; the test group underwent removal of granulation tissue and soft microbial deposits by cleaning the root surface with a microbrush and saline solution, aiming at cementum preservation. Guided tissue regeneration (GTR) was applied to both groups. Twenty-one days later, the newly formed tissue under the membrane was assessed for the expression of the following genes: alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN), platelet-derived growth factor-alpha (PDGFA), bone sialoprotein (BSP), and basic fibroblast growth factor (bFGF). Data analysis demonstrated that mRNA levels for PDGFA, BSP, and bFGF were higher in the sites where root cementum was kept in place compared to the sites where root cementum was removed completely as part of the periodontal therapy (P <0.05); in contrast, OCN levels were lower (P <0.05). No difference for ALP or OPN was observed between the control and test groups (P >0.05). Root cementum may modulate the expression of growth and mineral-associated factors during periodontal regeneration.

RhBMP-2 loaded 3D-printed mesoporous silica/calcium phosphate cement porous scaffolds with enhanced vascularization and osteogenesis properties

NASA Astrophysics Data System (ADS)

Li, Cuidi; Jiang, Chuan; Deng, Yuan; Li, Tao; Li, Ning; Peng, Mingzheng; Wang, Jinwu

2017-01-01

A major limitation in the development of effective scaffolds for bone regeneration has been the limited vascularization of the regenerating tissue. Here, we propose the development of a novel calcium phosphate cement (CPC)-based scaffold combining the properties of mesoporous silica (MS) with recombinant human bone morphogenic protein-2 (rhBMP-2) to facilitate vascularization and osteogenesis. Specifically, the development of a custom MS/CPC paste allowed the three-dimensional (3D) printing of scaffolds with a defined macroporous structure and optimized silicon (Si) ions release profile to promote the ingrowth of vascular tissue at an early stage after implantation in support of tissue viability and osteogenesis. In addition, the scaffold microstructure allowed the prolonged release of rhBMP-2, which in turn significantly stimulated the osteogenesis of human bone marrow stromal cells in vitro and of bone regeneration in vivo as shown in a rabbit femur defect repair model. Thus, the combination MS/CPC/rhBMP-2 scaffolds might provide a solution to issues of tissue necrosis during the regeneration process and therefore might be able to be readily developed into a useful tool for bone repair in the clinic.

Macrophages in Injured Skeletal Muscle: A Perpetuum Mobile Causing and Limiting Fibrosis, Prompting or Restricting Resolution and Regeneration

PubMed Central

Bosurgi, Lidia; Manfredi, Angelo A.; Rovere-Querini, Patrizia

2011-01-01

Macrophages are present in regenerating skeletal muscles and participate in the repair process. This is due to a unique feature of macrophages, i.e., their ability to perceive signals heralding ongoing tissue injury and to broadcast the news to cells suited at regenerating the tissue such as stem and progenitor cells. Macrophages play a complex role in the skeletal muscle, probably conveying information on the pattern of healing which is appropriate to ensure an effective healing of the tissue, yielding novel functional fibers. Conversely, they are likely to be involved in limiting the efficacy of regeneration, with formation of fibrotic scars and fat replacement of the tissue when the original insult persists. In this review we consider the beneficial versus the detrimental actions of macrophages during the response to muscle injury, with attention to the available information on the molecular code macrophages rely on to guide, throughout the various phases of muscle healing, the function of conventional and unconventional stem cells. Decrypting this code would represent a major step forward toward the establishment of novel targeted therapies for muscle diseases. PMID:22566851

Recent advances of basic materials to obtain electrospun polymeric nanofibers for medical applications

NASA Astrophysics Data System (ADS)

Manea, L. R.; Hristian, L.; Leon, A. L.; Popa, A.

2016-08-01

The most important applications of electrospun polymeric nanofibers are by far those from biomedical field. From the biological point of view, almost all the human tissues and organs consist of nanofibroas structures. The examples include the bone, dentine, cartilage, tendons and skin. All these are characterized through different fibrous structures, hierarchically organized at nanometer scale. Electrospinning represents one of the nanotechnologies that permit to obtain such structures for cell cultures, besides other technologies, such as selfassembling and phase separation technologies. The basic materials used to produce electrospun nanofibers can be natural or synthetic, having polymeric, ceramic or composite nature. These materials are selected depending of the nature and structure of the tissue meant to be regenerated, namely: for the regeneration of smooth tissues regeneration one needs to process through electrospinning polymeric basic materials, while in order to obtain the supports for the regeneration of hard tissues one must mainly use ceramic materials or composite structures that permit imbedding the bioactive substances in distinctive zones of the matrix. This work presents recent studies concerning basic materials used to obtain electrospun polymeric nanofibers, and real possibilities to produce and implement these nanofibers in medical bioengineering applications.

Ectopic Fgf signaling induces the intercalary response in developing chicken limb buds.

PubMed

Makanae, Aki; Satoh, Akira

2018-01-01

Intercalary pattern formation is an important regulatory step in amphibian limb regeneration. Amphibian limb regeneration is composed of multiple steps, including wounding, blastema formation, and intercalary pattern formation. Attempts have been made to transfer insights from regeneration-competent animals to regeneration-incompetent animalsat each step in the regeneration process. In the present study, we focused on the intercalary mechanism in chick limb buds. In amphibian limb regeneration, a proximodistal axis is organized as soon as a regenerating blastema is induced. Intermediate structures are subsequently induced (intercalated) between the established proximal and distal identities. Intercalary tissues are derived from proximal tissues. Fgf signaling mediates the intercalary response in amphibian limb regeneration. We attempted to transfer insights into intercalary regeneration from amphibian models to the chick limb bud. The zeugopodial part was dissected out, and the distal and proximal parts were conjunct at st. 24. Delivering ectopic Fgf2 + Fgf8 between the distal and proximal parts resulted in induction of zeugopodial elements. Examination of HoxA11 expression, apoptosis, and cell proliferation provides insights to compare with those in the intercalary mechanism of amphibian limb regeneration. Furthermore, the cellular contribution was investigated in both the chicken intercalary response and that of axolotl limb regeneration. We developed new insights into cellular contribution in amphibian intercalary regeneration, and found consistency between axolotl and chicken intercalary responses. Our findings demonstrate that the same principal of limb regeneration functions between regeneration-competent and -incompetent animals. In this context, we propose the feasibility of the induction of the regeneration response in amniotes.

Small Molecule based Musculoskeletal Regenerative Engineering

PubMed Central

Lo, Kevin W.-H.; Jiang, Tao; Gagnon, Keith A.; Nelson, Clarke; Laurencin, Cato T.

2014-01-01

Clinicians and scientists working in the field of regenerative engineering are actively investigating a wide range of methods to promote musculoskeletal tissue regeneration. Small molecule-mediated tissue regeneration is emerging as a promising strategy for regenerating various musculoskeletal tissues and a large number of small molecule compounds have been recently discovered as potential bioactive molecules for musculoskeletal tissue repair and regeneration. In this review, we summarize the recent literature encompassing the past four years in the area of small bioactive molecule for promoting repair and regeneration of various musculoskeletal tissues including bone, muscle, cartilage, tendon, and nerve. PMID:24405851

Connective Tissue Fibroblast Properties Are Position-Dependent during Mouse Digit Tip Regeneration

PubMed Central

Wu, Yuanyuan; Wang, Karen; Karapetyan, Adrine; Fernando, Warnakulusuriya Akash; Simkin, Jennifer; Han, Manjong; Rugg, Elizabeth L.; Muneoka, Ken

2013-01-01

A key factor that contributes to the regenerative ability of regeneration-competent animals such as the salamander is their use of innate positional cues that guide the regeneration process. The limbs of mammals has severe regenerative limitations, however the distal most portion of the terminal phalange is regeneration competent. This regenerative ability of the adult mouse digit is level dependent: amputation through the distal half of the terminal phalanx (P3) leads to successful regeneration, whereas amputation through a more proximal location, e.g. the subterminal phalangeal element (P2), fails to regenerate. Do the connective tissue cells of the mammalian digit play a role similar to that of the salamander limb in controlling the regenerative response? To begin to address this question, we isolated and cultured cells of the connective tissue surrounding the phalangeal bones of regeneration competent (P3) and incompetent (P2) levels. Despite their close proximity and localization, these cells show very distinctive profiles when characterized in vitro and in vivo. In vitro studies comparing their proliferation and position-specific interactions reveal that cells isolated from the P3 and P2 are both capable of organizing and differentiating epithelial progenitors, but with different outcomes. The difference in interactions are further characterized with three-dimension cultures, in which P3 regenerative cells are shown to lack a contractile response that is seen in other fibroblast cultures, including the P2 cultures. In in vivo engraftment studies, the difference between these two cell lines is made more apparent. While both P2 and P3 cells participated in the regeneration of the terminal phalanx, their survival and proliferative indices were distinct, thus suggesting a key difference in their ability to interact within a regeneration permissive environment. These studies are the first to demonstrate distinct positional characteristics of connective tissue cells that are associated with their regenerative capabilities. PMID:23349966

Regeneration and repair of human digits and limbs: fact and fiction

PubMed Central

Cheng, Tsun‐Chih

2015-01-01

Abstract A variety of digit and limb repair and reconstruction methods have been used in different clinical settings, but regeneration remains an item on every plastic surgeon's “wish list.” Although surgical salvage techniques are continually being improved, unreplantable digits and limbs are still abundant. We comprehensively review the structural and functional salvage methods in clinical practice, from the peeling injuries of small distal fingertips to multisegmented amputated limbs, and the developmental and tissue engineering approaches for regenerating human digits and limbs in the laboratory. Although surgical techniques have forged ahead, there are still situations in which digits and limbs are unreplantable. Advances in the field are delineated, and the regeneration processes of salamander limbs, lizard tails, and mouse digits and each component of tissue engineering approaches for digit‐ and limb‐building are discussed. Although the current technology is promising, there are many challenges in human digit and limb regeneration. We hope this review inspires research on the critical gap between clinical and basic science, and leads to more sophisticated digit and limb loss rescue and regeneration innovations. PMID:27499873

Diet-Induced Obesity Affects Muscle Regeneration After Murine Blunt Muscle Trauma-A Broad Spectrum Analysis.

PubMed

Xu, Pengfei; Werner, Jens-Uwe; Milerski, Sebastian; Hamp, Carmen M; Kuzenko, Tatjana; Jähnert, Markus; Gottmann, Pascal; de Roy, Luisa; Warnecke, Daniela; Abaei, Alireza; Palmer, Annette; Huber-Lang, Markus; Dürselen, Lutz; Rasche, Volker; Schürmann, Annette; Wabitsch, Martin; Knippschild, Uwe

2018-01-01

Injury to skeletal muscle affects millions of people worldwide. The underlying regenerative process however, is a very complex mechanism, time-wise highly coordinated, and subdivided in an initial inflammatory, a regenerative and a remodeling phase. Muscle regeneration can be impaired by several factors, among them diet-induced obesity (DIO). In order to evaluate if obesity negatively affects healing processes after trauma, we utilized a blunt injury approach to damage the extensor iliotibialis anticus muscle on the left hind limb of obese and normal weight C57BL/6J without showing any significant differences in force input between normal weight and obese mice. Magnetic resonance imaging (MRI) of the injury and regeneration process revealed edema formation and hemorrhage exudate in muscle tissue of normal weight and obese mice. In addition, morphological analysis of physiological changes revealed tissue necrosis, immune cell infiltration, extracellular matrix (ECM) remodeling, and fibrosis formation in the damaged muscle tissue. Regeneration was delayed in muscles of obese mice, with a higher incidence of fibrosis formation due to hampered expression levels of genes involved in ECM organization. Furthermore, a detailed molecular fingerprint in different stages of muscle regeneration underlined a delay or even lack of a regenerative response to injury in obese mice. A time-lapse heatmap determined 81 differentially expressed genes (DEG) with at least three hits in our model at all-time points, suggesting key candidates with a high impact on muscle regeneration. Pathway analysis of the DEG revealed five pathways with a high confidence level: myeloid leukocyte migration, regulation of tumor necrosis factor production, CD4-positive, alpha-beta T cell differentiation, ECM organization, and toll-like receptor (TLR) signaling. Moreover, changes in complement-, Wnt-, and satellite cell-related genes were found to be impaired in obese animals after trauma. Furthermore, histological satellite cell evaluation showed lower satellite cell numbers in the obese model upon injury. Ankrd1, C3ar1, Ccl8, Mpeg1 , and Myog expression levels were also verified by qPCR. In summary, increased fibrosis formation, the reduction of Pax7 + satellite cells as well as specific changes in gene expression and signaling pathways could explain the delay of tissue regeneration in obese mice post trauma.

Tissue regeneration in dentistry: Can salamanders provide insight?

PubMed

Sader, F; Denis, J-F; Roy, S

2018-05-01

The ability to regenerate damaged tissues would be of tremendous benefit for medicine and dentistry. Unfortunately, humans are unable to regenerate tissues such as teeth and fingers or to repair injured spinal cord. With an aging population, health problems are more prominent and dentistry is no exception as loss of bone tissue in the orofacial sphere from periodontal disease is on the rise. Humans can repair oral soft tissues exceptionally well; however, hard tissues, such as bone and teeth, are devoid of the ability to repair well or at all. Fortunately, Mother Nature has solved nearly every problem that we would like to solve for our own benefit and tissue regeneration is no exception. By studying animals that can regenerate, like Axolotls (Mexican salamander), we hope to find ways to stimulate regeneration in humans. We will discuss the role of the transforming growth factor beta cytokines as they are central to wound healing in humans and regeneration in Axolotls. We will also compare wound healing in humans (skin and oral mucosa) to Axolotl skin wound healing and limb regeneration. Finally, we will address the problem of bone regeneration and present results in salamanders which indicate that in order to regenerate bone you need to recruit non-bone cells. Fundamental research, such as the work being performed in animals that can regenerate, offers insight to help understand why some treatments are successful while others fail when it comes to specific tissues such as bones. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The use of embryonic cells in the treatment of osteochondral defects of the knee: an ovine in vivo study.

PubMed

Manunta, Andrea Fabio; Zedde, Pietro; Pilicchi, Susanna; Rocca, Stefano; Pool, Roy R; Dattena, Maria; Masala, Gerolamo; Mara, Laura; Casu, Sara; Sanna, Daniela; Manunta, Maria Lucia; Passino, Eraldo Sanna

2016-01-01

the aim of this study was to determine whether local delivery of embryonic stem-like (ESL) cells into osteochondral defects in the femoral condyles of sheep would enhance regeneration of hyaline articular cartilage. male ESL cells embedded in fibrin glue were engrafted into osteochondral defects in the medial condyles (ESL-M) of the left femur in 22 ewes. An identical defect was created in the medial condyle of the contralateral stifle joint and left untreated as a control (empty defect, ED). The ewes were divided into 5 groups. Four sheep each were euthanized at 1, 2, 6, and 12 months from surgery, and 6 ewes were euthanized 24 months post-implantation. To study the effect of varying loads on the long-term regeneration process, an identical defect was also created and ESL cell engraftment performed in the lateral condyle (ESL-L) of the left stifle joint of the animals in the 12- and 24-month groups. The evaluation of regenerated tissue was performed by biomechanical, macroscopic, histological, immunohistochemical (collagen type II) and fluorescent in situ hybridization (FISH) assays. no significant differences were found between treated and control sites in the biomechanical assays at any time point. ESL cell grafts showed significantly greater macroscopic evidence of regeneration as compared to controls at 24 months after surgery; significantly better histological evidence of repair in ESL-M samples versus controls was found throughout the considered period. At 24 months from surgery there was significantly improved integration of graft edges with the host tissue in the ESL-M as compared to the ESL-L samples, demonstrating that load bearing positively affects the long-term regeneration process. ESL cells enhanced the regeneration of hyaline cartilage. FISH confirmed that the regenerative tissue originated from ESL cells. ESL cells are able to self-renew for prolonged periods without differentiation and, most importantly, to differentiate into a large variety of tissues.

The use of embryonic cells in the treatment of osteochondral defects of the knee: an ovine in vivo study

PubMed Central

MANUNTA, ANDREA FABIO; ZEDDE, PIETRO; PILICCHI, SUSANNA; ROCCA, STEFANO; POOL, ROY R.; DATTENA, MARIA; MASALA, GEROLAMO; MARA, LAURA; CASU, SARA; SANNA, DANIELA; MANUNTA, MARIA LUCIA; PASSINO, ERALDO SANNA

2016-01-01

Purpose the aim of this study was to determine whether local delivery of embryonic stem-like (ESL) cells into osteochondral defects in the femoral condyles of sheep would enhance regeneration of hyaline articular cartilage. Methods male ESL cells embedded in fibrin glue were engrafted into osteochondral defects in the medial condyles (ESL-M) of the left femur in 22 ewes. An identical defect was created in the medial condyle of the contralateral stifle joint and left untreated as a control (empty defect, ED). The ewes were divided into 5 groups. Four sheep each were euthanized at 1, 2, 6, and 12 months from surgery, and 6 ewes were euthanized 24 months post-implantation. To study the effect of varying loads on the long-term regeneration process, an identical defect was also created and ESL cell engraftment performed in the lateral condyle (ESL-L) of the left stifle joint of the animals in the 12- and 24-month groups. The evaluation of regenerated tissue was performed by biomechanical, macroscopic, histological, immunohistochemical (collagen type II) and fluorescent in situ hybridization (FISH) assays. Results no significant differences were found between treated and control sites in the biomechanical assays at any time point. ESL cell grafts showed significantly greater macroscopic evidence of regeneration as compared to controls at 24 months after surgery; significantly better histological evidence of repair in ESL-M samples versus controls was found throughout the considered period. At 24 months from surgery there was significantly improved integration of graft edges with the host tissue in the ESL-M as compared to the ESL-L samples, demonstrating that load bearing positively affects the long-term regeneration process. Conclusions ESL cells enhanced the regeneration of hyaline cartilage. FISH confirmed that the regenerative tissue originated from ESL cells. Clinical Relevance ESL cells are able to self-renew for prolonged periods without differentiation and, most importantly, to differentiate into a large variety of tissues. PMID:27602346

Computer aided design of architecture of degradable tissue engineering scaffolds.

PubMed

Heljak, M K; Kurzydlowski, K J; Swieszkowski, W

2017-11-01

One important factor affecting the process of tissue regeneration is scaffold stiffness loss, which should be properly balanced with the rate of tissue regeneration. The aim of the research reported here was to develop a computer tool for designing the architecture of biodegradable scaffolds fabricated by melt-dissolution deposition systems (e.g. Fused Deposition Modeling) to provide the required scaffold stiffness at each stage of degradation/regeneration. The original idea presented in the paper is that the stiffness of a tissue engineering scaffold can be controlled during degradation by means of a proper selection of the diameter of the constituent fibers and the distances between them. This idea is based on the size-effect on degradation of aliphatic polyesters. The presented computer tool combines a genetic algorithm and a diffusion-reaction model of polymer hydrolytic degradation. In particular, we show how to design the architecture of scaffolds made of poly(DL-lactide-co-glycolide) with the required Young's modulus change during hydrolytic degradation.

Development of tyrosinase-based reporter genes for preclinical photoacoustic imaging of mesenchymal stem cells

NASA Astrophysics Data System (ADS)

Märk, Julia; Ruschke, Karen; Dortay, Hakan; Schreiber, Isabelle; Sass, Andrea; Qazi, Taimoor; Pumberger, Matthias; Laufer, Jan

2014-03-01

The capability to image stem cells in vivo in small animal models over extended periods of time is important to furthering our understanding of the processes involved in tissue regeneration. Photoacoustic imaging is suited to this application as it can provide high resolution (tens of microns) absorption-based images of superficial tissues (cm depths). However, stem cells are rare, highly migratory, and can divide into more specialised cells. Genetic labelling strategies are therefore advantageous for their visualisation. In this study, methods for the transfection and viral transduction of mesenchymal stem cells with reporter genes for the co-expression of tyrosinase and a fluorescent protein (mCherry). Initial photoacoustic imaging experiments of tyrosinase expressing cells in small animal models of tissue regeneration were also conducted. Lentiviral transduction methods were shown to result in stable expression of tyrosinase and mCherry in mesenchymal stem cells. The results suggest that photoacoustic imaging using reporter genes is suitable for the study of stem cell driven tissue regeneration in small animals.

Molecular insight into the association between cartilage regeneration and ear wound healing in genetic mouse models: targeting new genes in regeneration.

PubMed

Rai, Muhammad Farooq; Schmidt, Eric J; McAlinden, Audrey; Cheverud, James M; Sandell, Linda J

2013-11-06

Tissue regeneration is a complex trait with few genetic models available. Mouse strains LG/J and MRL are exceptional healers. Using recombinant inbred strains from a large (LG/J, healer) and small (SM/J, nonhealer) intercross, we have previously shown a positive genetic correlation between ear wound healing, knee cartilage regeneration, and protection from osteoarthritis. We hypothesize that a common set of genes operates in tissue healing and articular cartilage regeneration. Taking advantage of archived histological sections from recombinant inbred strains, we analyzed expression of candidate genes through branched-chain DNA technology directly from tissue lysates. We determined broad-sense heritability of candidates, Pearson correlation of candidates with healing phenotypes, and Ward minimum variance cluster analysis for strains. A bioinformatic assessment of allelic polymorphisms within and near candidate genes was also performed. The expression of several candidates was significantly heritable among strains. Although several genes correlated with both ear wound healing and cartilage healing at a marginal level, the expression of four genes representing DNA repair (Xrcc2, Pcna) and Wnt signaling (Axin2, Wnt16) pathways was significantly positively correlated with both phenotypes. Cluster analysis accurately classified healers and nonhealers for seven out of eight strains based on gene expression. Specific sequence differences between LG/J and SM/J were identified as potential causal polymorphisms. Our study suggests a common genetic basis between tissue healing and osteoarthritis susceptibility. Mapping genetic variations causing differences in diverse healing responses in multiple tissues may reveal generic healing processes in pursuit of new therapeutic targets designed to induce or enhance regeneration and, potentially, protection from osteoarthritis.

Regeneration of the periodontium using enamel matrix derivative in combination with an injectable bone cement.

PubMed

Oortgiesen, Daniël A W; Meijer, Gert J; Bronckers, Antonius L J J; Walboomers, X Frank; Jansen, John A

2013-03-01

Enamel matrix derivative (EMD) has proven to enhance periodontal regeneration; however, its effect is mainly restricted to the soft periodontal tissues. Therefore, to stimulate not only the soft tissues, but also the hard tissues, in this study EMD is combined with an injectable calcium phosphate cement (CaP; bone graft material). The aim was to evaluate histologically the healing of a macroporous CaP in combination with EMD. Intrabony, three-wall periodontal defects (2 × 2 × 1.7 mm) were created mesial of the first upper molar in 15 rats (30 defects). Defects were randomly treated according to one of the three following strategies: EMD, calcium phosphate cement and EMD, or left empty. The animals were killed after 12 weeks, and retrieved samples were processed for histology and histomorphometry. Empty defects showed a reparative type of healing without periodontal ligament or bone regeneration. As measured with on a histological grading scale for periodontal regeneration, the experimental groups (EMD and CaP/EMD) scored equally, both threefold higher compared with empty defects. However, most bone formation was measured in the CaP/EMD group; addition of CAP to EMD significantly enhanced bone formation with 50 % compared with EMD alone. Within the limits of this animal study, the adjunctive use of EMD in combination with an injectable cement, although it did not affect epithelial downgrowth, appeared to be a promising treatment modality for regeneration of bone and ligament tissues in the periodontium. The adjunctive use of EMD in combination with an injectable cement appears to be a promising treatment modality for regeneration of the bone and ligament tissues in the periodontium.

Boon and Bane of Inflammation in Bone Tissue Regeneration and Its Link with Angiogenesis.

PubMed

Schmidt-Bleek, Katharina; Kwee, Brian J; Mooney, David J; Duda, Georg N

2015-08-01

Delayed healing or nonhealing of bone is an important clinical concern. Although bone, one of the two tissues with scar-free healing capacity, heals in most cases, healing is delayed in more than 10% of clinical cases. Treatment of such delayed healing condition is often painful, risky, time consuming, and expensive. Tissue healing is a multistage regenerative process involving complex and well-orchestrated steps, which are initiated in response to injury. At best, these steps lead to scar-free tissue formation. At the onset of healing, during the inflammatory phase, stationary and attracted macrophages and other immune cells at the fracture site release cytokines in response to injury. This initial reaction to injury is followed by the recruitment, proliferation, and differentiation of mesenchymal stromal cells, synthesis of extracellular matrix proteins, angiogenesis, and finally tissue remodeling. Failure to heal is often associated with poor revascularization. Since blood vessels mediate the transport of circulating cells, oxygen, nutrients, and waste products, they appear essential for successful healing. The strategy of endogenous regeneration in a tissue such as bone is interesting to analyze since it may represent a blueprint of successful tissue formation. This review highlights the interdependency of the time cascades of inflammation, angiogenesis, and tissue regeneration. A better understanding of these inter-relations is mandatory to early identify patients at risk as well as to overcome critical clinical conditions that limit healing. Instead of purely tolerating the inflammatory phase, modulations of inflammation (immunomodulation) might represent a valid therapeutic strategy to enhance angiogenesis and foster later phases of tissue regeneration.

Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model

PubMed Central

Soejima, T.; Murakami, H.; Noguchi, K.; Shiba, N.; Nagata, K.

2016-01-01

Objectives The objective of this study was to determine if the use of fascia lata as a tendon regeneration guide (placed into the tendon canal following harvesting the semitendinosus tendon) would improve the incidence of tissue regeneration and prevent fatty degeneration of the semitendinosus muscle. Materials and Methods Bilateral semitendinosus tendons were harvested from rabbits using a tendon stripper. On the inducing graft (IG) side, the tendon canal and semitendinosus tibial attachment site were connected by the fascia lata, which was harvested at the same width as the semitendinosus tendon. On the control side, no special procedures were performed. Two groups of six rabbits were killed at post-operative weeks 4 and 8, respectively. In addition, three healthy rabbits were killed to obtain normal tissue. We evaluated the incidence of tendon tissue regeneration, cross-sectional area of the regenerated tendon tissue and proportion of fatty tissue in the semitendinosus muscle. Results At post-operative week 8, the distal end of the regenerated tissue reached the vicinity of the tibial insertion on the control side in two of six specimens. On the IG side, the regenerated tissue maintained continuity with the tibial insertion in all specimens. The cross-sectional area of the IG side was significantly greater than that of the control side. The proportion of fatty tissue in the semitendinosus muscle on the IG side was comparable with that of the control side, but was significantly greater than that of the normal muscle. Conclusions Tendon tissue regenerated with the fascia lata graft was thicker than naturally occurring regenerated tissue. However, the proportion of fatty tissue in the semitendinosus muscle was greater than that of normal muscle. Cite this article: K. Tabuchi, T. Soejima, H. Murakami, K. Noguchi, N. Shiba, K. Nagata. Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model. Bone Joint Res 2016;5:247–252. DOI: 10.1302/2046-3758.56.2000585. PMID:27340141

In vitro models for evaluation of periodontal wound healing/regeneration.

PubMed

Weinreb, Miron; Nemcovsky, Carlos E

2015-06-01

Periodontal wound healing and regeneration are highly complex processes, involving cells, matrices, molecules and genes that must be properly choreographed and orchestrated. As we attempt to understand and influence these clinical entities, we need experimental models to mimic the various aspects of human wound healing and regeneration. In vivo animal models that simulate clinical situations of humans can be costly and cumbersome. In vitro models have been devised to dissect wound healing/regeneration processes into discrete, analyzable steps. For soft tissue (e.g. gingival) healing, in vitro models range from simple culture of cells grown in monolayers and exposed to biological modulators or physical effectors and materials, to models in which cells are 'injured' by scraping and subsequently the 'wound' is filled with new or migrating cells, to three-dimensional models of epithelial-mesenchymal recombination or tissue explants. The cells employed are gingival keratinocytes, fibroblasts or endothelial cells, and their proliferation, migration, attachment, differentiation, survival, gene expression, matrix production or capillary formation are measured. Studies of periodontal regeneration also include periodontal ligament fibroblasts or progenitors, osteoblasts or osteoprogenitors, and cementoblasts. Regeneration models measure cellular proliferation, attachment and migration, as well as gene expression, transfer and differentiation into a mineralizing phenotype and biomineralization. Only by integrating data from models on all levels (i.e. a single cell to the whole organism) can various critical aspects of periodontal wound healing/regeneration be fully evaluated. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Hematological Analysis of the Ascidian Botrylloides leachii (Savigny, 1816) During Whole-Body Regeneration.

PubMed

Blanchoud, Simon; Zondag, Lisa; Lamare, Miles D; Wilson, Megan J

2017-06-01

Whole-body regeneration (WBR)-the formation of an entire adult from only a small fragment of its own tissue-is extremely rare among chordates. Exceptionally, in the colonial ascidian Botrylloides leachii (Savigny, 1816) a fully functional adult is formed from their common vascular system after ablation of all adults from the colony in just 10 d, thanks to their high blastogenetic potential. While previous studies have identified key genetic markers and morphological changes, no study has yet focused on the hematological aspects of regeneration despite the major involvement of the remaining vascular system and the contained hemocytes in this process. To dissect this process, we analyzed colony blood flow patterns using time-lapse microscopy to obtain a quantitative description of the velocity, reversal pattern, and average distance traveled by hemocytes. We also observed that flows present during regeneration are powered by temporally and spatially synchronized contractions of the terminal ampullae. In addition, we revised previous studies of B. leachii hematology as well as asexual development using histological sectioning and compared the role played by hemocytes during WBR. We found that regeneration starts with a rapid healing response characterized by hemocyte aggregation and infiltration of immunocytes, followed by increased activity of hemoblasts, recruitment of macrophage-like cells for clearing the tissues of debris, and their subsequent disappearance from the circulation concomitant with the maturation of a single regenerated adult. Overall, we provide a detailed account of the hematological properties of regenerating B. leachii colonies, providing novel lines of inquiry toward the decipherment of regeneration in chordates.

Application of Detergents or High Hydrostatic Pressure as Decellularization Processes in Uterine Tissues and Their Subsequent Effects on In Vivo Uterine Regeneration in Murine Models

PubMed Central

Hirota, Yasushi; Aizawa, Masanori; Yoshino, Osamu; Kishida, Akio; Osuga, Yutaka; Saito, Shigeru; Ushida, Takashi; Furukawa, Katsuko S.

2014-01-01

Infertility caused by ovarian or tubal problems can be treated using In Vitro Fertilization and Embryo Transfer (IVF-ET); however, this is not possible for women with uterine loss and malformations that require uterine reconstruction for the treatment of their infertility. In this study, we are the first to report the usefulness of decellularized matrices as a scaffold for uterine reconstruction. Uterine tissues were extracted from Sprague Dawley (SD) rats and decellularized using either sodium dodecyl sulfate (SDS) or high hydrostatic pressure (HHP) at optimized conditions. Histological staining and quantitative analysis showed that both SDS and HHP methods effectively removed cells from the tissues with, specifically, a significant reduction of DNA contents for HHP constructs. HHP constructs highly retained the collagen content, the main component of extracellular matrices in uterine tissue, compared to SDS constructs and had similar content levels of collagen to the native tissue. The mechanical strength of the HHP constructs was similar to that of the native tissue, while that of the SDS constructs was significantly elevated. Transmission electron microscopy (TEM) revealed no apparent denaturation of collagen fibers in the HHP constructs compared to the SDS constructs. Transplantation of the decellularized tissues into rat uteri revealed the successful regeneration of the uterine tissues with a 3-layer structure 30 days after the transplantation. Moreover, a lot of epithelial gland tissue and Ki67 positive cells were detected. Immunohistochemical analyses showed that the regenerated tissues have a normal response to ovarian hormone for pregnancy. The subsequent pregnancy test after 30 days transplantation revealed successful pregnancy for both the SDS and HHP groups. These findings indicate that the decellularized matrix from the uterine tissue can be a potential scaffold for uterine regeneration. PMID:25057942

A preliminary study of differentially expressed genes in expanded skin and normal skin: implications for adult skin regeneration.

PubMed

Yang, Mei; Liang, Yimin; Sheng, Lingling; Shen, Guoxiong; Liu, Kai; Gu, Bin; Meng, Fanjun; Li, Qingfeng

2011-03-01

In adults, severely damaged skin heals by scar formation and cannot regenerate to the original skin structure. However, tissue expansion is an exception, as normal skin regenerates under the mechanical stretch resulting from tissue expansion. This technique has been used clinically for defect repair and organ reconstruction for decades. However, the phenomenon of adult skin regeneration during tissue expansion has caused little attention, and the mechanism of skin regeneration during tissue expansion has not been fully understood. In this study, microarray analysis was performed on expanded human skin and normal human skin. Significant difference was observed in 77 genes, which suggest a network of several integrated cascades, including cytokines, extracellular, cytoskeletal, transmembrane molecular systems, ion or ion channels, protein kinases and transcriptional systems, is involved in the skin regeneration during expansion. Among these, the significant expression of some regeneration related genes, such as HOXA5, HOXB2 and AP1, was the first report in tissue expansion. Data in this study suggest a list of candidate genes, which may help to elucidate the fundamental mechanism of skin regeneration during tissue expansion and which may have implications for postnatal skin regeneration and therapeutic interventions in wound healing.

Nanofiber Nerve Guide for Peripheral Nerve Repair and Regeneration

DTIC Science & Technology

2016-04-01

faster regeneration and functional recovery. Peripheral nerve injury is a common complication of complex tissue trauma and often results in significant...having poor regeneration overall, the areas of regenerating nerve tissue could often be found in sections of the nerve guide where luminal spaces of...conducted in this Aim also provided important insight into the NGC design parameters necessary to allow for maximum nerve tissue ingrowth and regeneration

PhOTO Zebrafish: A Transgenic Resource for In Vivo Lineage Tracing during Development and Regeneration

PubMed Central

Dempsey, William P.; Fraser, Scott E.; Pantazis, Periklis

2012-01-01

Background Elucidating the complex cell dynamics (divisions, movement, morphological changes, etc.) underlying embryonic development and adult tissue regeneration requires an efficient means to track cells with high fidelity in space and time. To satisfy this criterion, we developed a transgenic zebrafish line, called PhOTO, that allows photoconvertible optical tracking of nuclear and membrane dynamics in vivo. Methodology PhOTO zebrafish ubiquitously express targeted blue fluorescent protein (FP) Cerulean and photoconvertible FP Dendra2 fusions, allowing for instantaneous, precise targeting and tracking of any number of cells using Dendra2 photoconversion while simultaneously monitoring global cell behavior and morphology. Expression persists through adulthood, making the PhOTO zebrafish an excellent tool for studying tissue regeneration: after tail fin amputation and photoconversion of a ∼100µm stripe along the cut area, marked differences seen in how cells contribute to the new tissue give detailed insight into the dynamic process of regeneration. Photoconverted cells that contributed to the regenerate were separated into three distinct populations corresponding to the extent of cell division 7 days after amputation, and a subset of cells that divided the least were organized into an evenly spaced, linear orientation along the length of the newly regenerating fin. Conclusions/Significance PhOTO zebrafish have wide applicability for lineage tracing at the systems-level in the early embryo as well as in the adult, making them ideal candidate tools for future research in development, traumatic injury and regeneration, cancer progression, and stem cell behavior. PMID:22431986

Functional joint regeneration is achieved using reintegration mechanism in Xenopus laevis

PubMed Central

Yamada, Shigehito

2016-01-01

Abstract A functional joint requires integration of multiple tissues: the apposing skeletal elements should form an interlocking structure, and muscles should insert into skeletal tissues via tendons across the joint. Whereas newts can regenerate functional joints after amputation, Xenopus laevis regenerates a cartilaginous rod without joints, a “spike.” Previously we reported that the reintegration mechanism between the remaining and regenerated tissues has a significant effect on regenerating joint morphogenesis during elbow joint regeneration in newt. Based on this insight into the importance of reintegration, we amputated frogs’ limbs at the elbow joint and found that frogs could regenerate a functional elbow joint between the remaining tissues and regenerated spike. During regeneration, the regenerating cartilage was partially connected to the remaining articular cartilage to reform the interlocking structure of the elbow joint at the proximal end of the spike. Furthermore, the muscles of the remaining part inserted into the regenerated spike cartilage via tendons. This study might open up an avenue for analyzing molecular and cellular mechanisms of joint regeneration using Xenopus. PMID:27499877

Mild process to design silk scaffolds with reduced β-sheet structure and various topographies at nanometer scale

PubMed Central

Pei, Yazhen; Liu, Xi; Liu, Shanshan; Lu, Qiang; Liu, Jing; Kaplan, David L; Zhu, Hesun

2014-01-01

Three-dimensional (3D) porous silk scaffolds with good biocompatibility and minimal immunogenicity, have promising applications in different tissue regenerations. However, a challenge remains to effectively fabricate their microstructures and mechanical properties to satisfy specific requirements of different tissues. In this study, silk scaffolds were fabricated to form extracellular matrix (ECM) mimetic nanofibrous architecture in a mild process. A slowly increasing concentration process was applied to regulate silk self-assembly into nanofibers in aqueous solution. Then glycerol was blended with the nanofiber solution and induced silk crystallization in lyophilization process, endowing freeze-dried scaffolds water-stability. The glycerol was leached from the scaffolds, leaving similar porous structure at a micrometer scale but different topographies at nanoscale. Compared to previous salt-leached and methanol annealed scaffolds, the present scaffolds showed lower β-sheet content, softer mechanical property, and improved cell growth and differentiation behaviors, implying their promising future as platforms for controlling stem cell fate and soft tissue regeneration. PMID:25463497

Synthetic Phage for Tissue Regeneration

PubMed Central

Merzlyak, Anna; Lee, Seung-Wuk

2014-01-01

Controlling structural organization and signaling motif display is of great importance to design the functional tissue regenerating materials. Synthetic phage, genetically engineered M13 bacteriophage has been recently introduced as novel tissue regeneration materials to display a high density of cell-signaling peptides on their major coat proteins for tissue regeneration purposes. Structural advantages of their long-rod shape and monodispersity can be taken together to construct nanofibrous scaffolds which support cell proliferation and differentiation as well as direct orientation of their growth in two or three dimensions. This review demonstrated how functional synthetic phage is designed and subsequently utilized for tissue regeneration that offers potential cell therapy. PMID:24991085

Growing Arabidopsis in vitro: cell suspensions, in vitro culture, and regeneration.

PubMed

Barkla, Bronwyn J; Vera-Estrella, Rosario; Pantoja, Omar

2014-01-01

An understanding of basic methods in Arabidopsis tissue culture is beneficial for any laboratory working on this model plant. Tissue culture refers to the aseptic growth of cells, organs, or plants in a controlled environment, in which physical, nutrient, and hormonal conditions can all be easily manipulated and monitored. The methodology facilitates the production of a large number of plants that are genetically identical over a relatively short growth period. Techniques, including callus production, cell suspension cultures, and plant regeneration, are all indispensable tools for the study of cellular biochemical and molecular processes. Plant regeneration is a key technology for successful stable plant transformation, while cell suspension cultures can be exploited for metabolite profiling and mining. In this chapter we report methods for the successful and highly efficient in vitro regeneration of plants and production of stable cell suspension lines from leaf explants of both Arabidopsis thaliana and Arabidopsis halleri.

Histological Evaluation of the Effect of Platelet-rich Plasma on Pulp Regeneration in Nonvital Open Apex Teeth: An Animal Study.

PubMed

Ghoddusi, Jamileh; Maghsudlu, Amir; Jafarzadeh, Hamid; Jafarian, Amirhossein; Forghani, Maryam

2017-11-01

Platelet-rich plasma (PRP), which is a concentration of growth factors found in platelets, may be a suitable material for pulp regeneration. The aim of this animal study was a histological evaluation of PRP on pulp regeneration in nonvital teeth with immature apices. A total of 40 premolar dogs' teeth were chosen for this study. After general anesthesia, the teeth were exposed, and subsequently, pulps were removed and the cavities were opened to the oral cavity. After 2 weeks, root canals were irrigated and disinfected with sodium hypochlorite with noninstrumentation technique, and triple antibiotic paste was placed inside the canals. Cavities were sealed with a temporary restoration. About 4 weeks later, canals were irrigated again and the teeth were randomly divided into three groups. Bleeding was evoked with overinstrumentation, then experimental materials for each group [PRP, mineral trioxide aggregate (MTA), and parafilm respectively] were placed over the bleeding, and orifices were sealed with MTA and glass ionomer. After 3 months, dogs were sacrificed and the teeth were separated from the jaws and sections prepared for histological evaluation. Regeneration was shown in 44.7% of the samples. About 47.3% of the samples in the MTA group and 42.1% of the samples in the PRP group showed regeneration; however, no regeneration was observed in the parafilm group. Chi-square test showed no significant difference between groups I and II. The soft regenerative tissue included pulp-like tissue and vessels. Mineralized regenerative tissue included cementum-like, periodontal ligament-like, and bone-like tissues. No normal pulp and nerve tissue were observed. Both PRP and MTA may be ideal scaffolds to accelerate the regeneration process. Pulp repair in immature permanent teeth with weak roots has a better outcome than replacement of the pulp with gutta-percha or biomaterials.

Evolving marine biomimetics for regenerative dentistry.

PubMed

Green, David W; Lai, Wing-Fu; Jung, Han-Sung

2014-05-13

New products that help make human tissue and organ regeneration more effective are in high demand and include materials, structures and substrates that drive cell-to-tissue transformations, orchestrate anatomical assembly and tissue integration with biology. Marine organisms are exemplary bioresources that have extensive possibilities in supporting and facilitating development of human tissue substitutes. Such organisms represent a deep and diverse reserve of materials, substrates and structures that can facilitate tissue reconstruction within lab-based cultures. The reason is that they possess sophisticated structures, architectures and biomaterial designs that are still difficult to replicate using synthetic processes, so far. These products offer tantalizing pre-made options that are versatile, adaptable and have many functions for current tissue engineers seeking fresh solutions to the deficiencies in existing dental biomaterials, which lack the intrinsic elements of biofunctioning, structural and mechanical design to regenerate anatomically correct dental tissues both in the culture dish and in vivo.

Evolving Marine Biomimetics for Regenerative Dentistry

PubMed Central

Green, David W.; Lai, Wing-Fu; Jung, Han-Sung

2014-01-01

New products that help make human tissue and organ regeneration more effective are in high demand and include materials, structures and substrates that drive cell-to-tissue transformations, orchestrate anatomical assembly and tissue integration with biology. Marine organisms are exemplary bioresources that have extensive possibilities in supporting and facilitating development of human tissue substitutes. Such organisms represent a deep and diverse reserve of materials, substrates and structures that can facilitate tissue reconstruction within lab-based cultures. The reason is that they possess sophisticated structures, architectures and biomaterial designs that are still difficult to replicate using synthetic processes, so far. These products offer tantalizing pre-made options that are versatile, adaptable and have many functions for current tissue engineers seeking fresh solutions to the deficiencies in existing dental biomaterials, which lack the intrinsic elements of biofunctioning, structural and mechanical design to regenerate anatomically correct dental tissues both in the culture dish and in vivo. PMID:24828293

Development of hybrid scaffolds using ceramic and hydrogel for articular cartilage tissue regeneration.

PubMed

Seol, Young-Joon; Park, Ju Young; Jeong, Wonju; Kim, Tae-Ho; Kim, Shin-Yoon; Cho, Dong-Woo

2015-04-01

The regeneration of articular cartilage consisting of hyaline cartilage and hydrogel scaffolds has been generally used in tissue engineering. However, success in in vivo studies has been rarely reported. The hydrogel scaffolds implanted into articular cartilage defects are mechanically unstable and it is difficult for them to integrate with the surrounding native cartilage tissue. Therefore, it is needed to regenerate cartilage and bone tissue simultaneously. We developed hybrid scaffolds with hydrogel scaffolds for cartilage tissue and with ceramic scaffolds for bone tissue. For in vivo study, hybrid scaffolds were press-fitted into osteochondral tissue defects in a rabbit knee joints and the cartilage tissue regeneration in blank, hydrogel scaffolds, and hybrid scaffolds was compared. In 12th week after implantation, the histological and immunohistochemical analyses were conducted to evaluate the cartilage tissue regeneration. In the blank and hydrogel scaffold groups, the defects were filled with fibrous tissues and the implanted hydrogel scaffolds could not maintain their initial position; in the hybrid scaffold group, newly generated cartilage tissues were morphologically similar to native cartilage tissues and were smoothly connected to the surrounding native tissues. This study demonstrates hybrid scaffolds containing hydrogel and ceramic scaffolds can provide mechanical stability to hydrogel scaffolds and enhance cartilage tissue regeneration at the defect site. © 2014 Wiley Periodicals, Inc.

Two Stage Repair of Composite Craniofacial Defects with Antibiotic Releasing Porous Poly(methyl methacrylate) Space Maintainers and Bone Regeneration

NASA Astrophysics Data System (ADS)

Spicer, Patrick

Craniofacial defects resulting from trauma and resection present many challenges to reconstruction due to the complex structure, combinations of tissues, and environment, with exposure to the oral, skin and nasal mucosal pathogens. Tissue engineering seeks to regenerate the tissues lost in these defects; however, the composite nature and proximity to colonizing bacteria remain difficult to overcome. Additionally, many tissue engineering approaches have further hurdles to overcome in the regulatory process to clinical translation. As such these studies investigated a two stage strategy employing an antibiotic-releasing porous polymethylmethacrylate space maintainer fabricated with materials currently part of products approved or cleared by the United States Food and Drug Administration, expediting the translation to the clinic. This porous space maintainer holds the bone defect open allowing soft tissue to heal around the defect. The space maintainer can then be removed and one regenerated in the defect. These studies investigated the individual components of this strategy. The porous space maintainer showed similar soft tissue healing and response to non-porous space maintainers in a rabbit composite tissue defect. The antibiotic-releasing space maintainers showed release of antibiotics from 1-5 weeks, which could be controlled by loading and fabrication parameters. In vivo, space maintainers releasing a high dose of antibiotics for an extended period of time increased soft tissue healing over burst release space maintainers in an infected composite tissue defect model in a rabbit mandible. Finally, stabilization of bone defects and regeneration could be improved through scaffold structures and delivery of a bone forming growth factor. These studies illustrate the possibility of the two stage strategy for repair of composite tissue defects of the craniofacial complex.

The Metabolic Microenvironment Steers Bone Tissue Regeneration.

PubMed

Loeffler, Julia; Duda, Georg N; Sass, F Andrea; Dienelt, Anke

2018-02-01

Over the past years, basic findings in cancer research have revealed metabolic symbiosis between different cell types to cope with high energy demands under limited nutrient availability. Although this also applies to regenerating tissues with disrupted physiological nutrient and oxygen supply, the impact of this metabolic cooperation and metabolic reprogramming on cellular development, fate, and function during tissue regeneration has widely been neglected so far. With this review, we aim to provide a schematic overview on metabolic links that have a high potential to drive tissue regeneration. As bone is, aside from liver, the only tissue that can regenerate without excessive scar tissue formation, we will use bone healing as an exemplarily model system. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantification of the tissue-culture induced variation in barley (Hordeum vulgare L.)

PubMed Central

Bednarek, Piotr T; Orłowska, Renata; Koebner, Robert MD; Zimny, Janusz

2007-01-01

Background When plant tissue is passaged through in vitro culture, many regenerated plants appear to be no longer clonal copies of their donor genotype. Among the factors that affect this so-called tissue culture induced variation are explant genotype, explant tissue origin, medium composition, and the length of time in culture. Variation is understood to be generated via a combination of genetic and/or epigenetic changes. A lack of any phenotypic variation between regenerants does not necessarily imply a concomitant lack of genetic (or epigenetic) change, and it is therefore of interest to assay the outcomes of tissue culture at the genotypic level. Results A variant of methylation sensitive AFLP, based on the isoschizomeric combinations Acc65I/MseI and KpnI/MseI was applied to analyze, at both the sequence and methylation levels, the outcomes of regeneration from tissue culture in barley. Both sequence mutation and alteration in methylation pattern were detected. Two sets of regenerants from each of five DH donor lines were compared. One set was derived via androgenesis, and the other via somatic embryogenesis, developed from immature embryos. These comparisons delivered a quantitative assessment of the various types of somaclonal variation induced. The average level of variation was 6%, of which almost 1.7% could be accounted for by nucleotide mutation, and the remainder by changes in methylation state. The nucleotide mutation rates and the rate of epimutations were substantially similar between the andro- and embryo-derived sets of regenerants across all the donors. Conclusion We have developed an AFLP based approach that is capable of describing the qualitative and quantitative characteristics of the tissue culture-induced variation. We believe that this approach will find particular value in the study of patterns of inheritance of somaclonal variation, since non-heritable variation is of little interest for the improvement of plant species which are sexually propagated. Of significant biological interest is the conclusion that the mode of regeneration has no significant effect on the balance between sequence and methylation state change induced by the tissue culture process. PMID:17335560

[Engineering a bone free flap for maxillofacial reconstruction: technical restrictions].

PubMed

Raoul, G; Myon, L; Chai, F; Blanchemain, N; Ferri, J

2011-09-01

Vascularisation is a key for success in bone tissue engineering. Creating a functional vascular network is an important concern so as to ensure vitality in regenerated tissues. Many strategies were developed to achieve this goal. One of these is cellular growth technique by perfusion bioreactor chamber. These new technical requirements came along with improved media and chamber receptacles: bioreactors (chapter 2). Some bone tissue engineering processes already have clinical applications but for volumes limited by the lack of vascularisation. Resorbable or non-resorbable membranes are an example. They are used separately or in association with bone grafts and they protect the graft during the revascularization process. Potentiated osseous regeneration uses molecular or cellular adjuvants (BMPs and autologous stem cells) to improve osseous healing. Significant improvements were made: integration of specific sequences, which may guide and enhance cells differentiation in scaffold; nano- or micro-patterned cell containing scaffolds. Finally, some authors consider the patient body as an ideal bioreactor to induce vascularisation in large volumes of grafted tissues. "Endocultivation", i.e., cellular culture inside the human body was proven to be feasible and safe. The properties of regenerated bone in the long run remain to be assessed. The objective to reach remains the engineering of an "in vitro" osseous free flap without morbidity. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Orthodontic-periodontal interactions: Orthodontic extrusion in interdisciplinary regenerative treatments.

PubMed

Paolone, Maria Giacinta; Kaitsas, Roberto

2018-06-01

Orthodontics is a periodontal treatment. "Guided orthodontic regeneration" (GOR) procedures use orthodontic movements in perio-restorative patients. The GOR technique includes a guided orthodontic "soft tissue" regeneration (GOTR) and a guided orthodontic "bone" regeneration (GOBR) with a plastic soft tissue approach and a regenerating reality. The increased amount of soft tissue gained with orthodontic movement can be used for subsequent periodontal regenerative techniques. The increased amount of bone can as well improve primary implant stability and, eventually, simplify a GTR technique to regenerate soft tissues, to restore tooth with external resorption in aesthetic zone or to extract a tooth to create new hard-soft tissue for adjacent teeth. Copyright © 2018. Published by Elsevier Masson SAS.

Localized delivery of growth factors for periodontal tissue regeneration: role, strategies, and perspectives.

PubMed

Chen, Fa-Ming; Shelton, Richard M; Jin, Yan; Chapple, Iain L C

2009-05-01

Difficulties associated with achieving predictable periodontal regeneration, means that novel techniques need to be developed in order to regenerate the extensive soft and hard tissue destruction that results from periodontitis. Localized delivery of growth factors to the periodontium is an emerging and versatile therapeutic approach, with the potential to become a powerful tool in future regenerative periodontal therapy. Optimized delivery regimes and well-defined release kinetics appear to be logical prerequisites for safe and efficacious clinical application of growth factors and to avoid unwanted side effects and toxicity. While adequate concentrations of growth factor(s) need to be appropriately localized, delivery vehicles are also expected to possess properties such as protein protection, precision in controlled release, biocompatibility and biodegradability, self-regulated therapeutic activity, potential for multiple delivery, and good cell/tissue penetration. Here, current knowledge, recent advances, and future possibilities of growth factor delivery strategies are outlined for periodontal regeneration. First, the role of those growth factors that have been implicated in the periodontal healing/regeneration process, general requirements for their delivery, and the different material types available are described. A detailed discussion follows of current strategies for the selection of devices for localized growth factor delivery, with particular emphasis placed upon their advantages and disadvantages and future prospects for ongoing studies in reconstructing the tooth supporting apparatus.

Combinatory approach for developing silk fibroin scaffolds for cartilage regeneration.

PubMed

Ribeiro, Viviana P; da Silva Morais, Alain; Maia, F Raquel; Canadas, Raphael F; Costa, João B; Oliveira, Ana L; Oliveira, Joaquim M; Reis, Rui L

2018-05-01

Several processing technologies and engineering strategies have been combined to create scaffolds with superior performance for efficient tissue regeneration. Cartilage tissue is a good example of that, presenting limited self-healing capacity together with a high elasticity and load-bearing properties. In this work, novel porous silk fibroin (SF) scaffolds derived from horseradish peroxidase (HRP)-mediated crosslinking of highly concentrated aqueous SF solution (16 wt%) in combination with salt-leaching and freeze-drying methodologies were developed for articular cartilage tissue engineering (TE) applications. The HRP-crosslinked SF scaffolds presented high porosity (89.3 ± 0.6%), wide pore distribution and high interconnectivity (95.9 ± 0.8%). Moreover, a large swelling capacity and favorable degradation rate were observed up to 30 days, maintaining the porous-like structure and β-sheet conformational integrity obtained with salt-leaching and freeze-drying processing. The in vitro studies supported human adipose-derived stem cells (hASCs) adhesion, proliferation, and high glycosaminoglycans (GAGs) synthesis under chondrogenic culture conditions. Furthermore, the chondrogenic differentiation of hASCs was assessed by the expression of chondrogenic-related markers (collagen type II, Sox-9 and Aggrecan) and deposition of cartilage-specific extracellular matrix for up to 28 days. The cartilage engineered constructs also presented structural integrity as their mechanical properties were improved after chondrogenic culturing. Subcutaneous implantation of the scaffolds in CD-1 mice demonstrated no necrosis or calcification, and deeply tissue ingrowth. Collectively, the structural properties and biological performance of these porous HRP-crosslinked SF scaffolds make them promising candidates for cartilage regeneration. In cartilage tissue engineering (TE), several processing technologies have been combined to create scaffolds for efficient tissue repair. In our study, we propose novel silk fibroin (SF) scaffolds derived from enzymatically crosslinked SF hydrogels processed by salt-leaching and freeze-drying technologies, for articular cartilage applications. Though these scaffolds, we were able to combine the elastic properties of hydrogel-based systems, with the stability, resilience and controlled porosity of scaffolds processed via salt-leaching and freeze-drying technologies. SF protein has been extensively explored for TE applications, as a result of its mechanical strength, elasticity, biocompatibility, and biodegradability. Thus, the structural, mechanical and biological performance of the proposed scaffolds potentiates their use as three-dimensional matrices for cartilage regeneration. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Leg regeneration is epigenetically regulated by histone H3K27 methylation in the cricket Gryllus bimaculatus.

PubMed

Hamada, Yoshimasa; Bando, Tetsuya; Nakamura, Taro; Ishimaru, Yoshiyasu; Mito, Taro; Noji, Sumihare; Tomioka, Kenji; Ohuchi, Hideyo

2015-09-01

Hemimetabolous insects such as the cricket Gryllus bimaculatus regenerate lost tissue parts using blastemal cells, a population of dedifferentiated proliferating cells. The expression of several factors that control epigenetic modification is upregulated in the blastema compared with differentiated tissue, suggesting that epigenetic changes in gene expression might control the differentiation status of blastema cells during regeneration. To clarify the molecular basis of epigenetic regulation during regeneration, we focused on the function of the Gryllus Enhancer of zeste [Gb'E(z)] and Ubiquitously transcribed tetratricopeptide repeat gene on the X chromosome (Gb'Utx) homologues, which regulate methylation and demethylation of histone H3 lysine 27 (H3K27), respectively. Methylated histone H3K27 in the regenerating leg was diminished by Gb'E(z)(RNAi) and was increased by Gb'Utx(RNAi). Regenerated Gb'E(z)(RNAi) cricket legs exhibited extra leg segment formation between the tibia and tarsus, and regenerated Gb'Utx(RNAi) cricket legs showed leg joint formation defects in the tarsus. In the Gb'E(z)(RNAi) regenerating leg, the Gb'dac expression domain expanded in the tarsus. By contrast, in the Gb'Utx(RNAi) regenerating leg, Gb'Egfr expression in the middle of the tarsus was diminished. These results suggest that regulation of the histone H3K27 methylation state is involved in the repatterning process during leg regeneration among cricket species via the epigenetic regulation of leg patterning gene expression. © 2015. Published by The Company of Biologists Ltd.

Wound repair in Pocillopora

USGS Publications Warehouse

Rodríguez-Villalobos, Jenny Carolina; Work, Thierry M.; Calderon-Aguileraa, Luis Eduardo

2016-01-01

Corals routinely lose tissue due to causes ranging from predation to disease. Tissue healing and regeneration are fundamental to the normal functioning of corals, yet we know little about this process. We described the microscopic morphology of wound repair in Pocillopora damicornis. Tissue was removed by airbrushing fragments from three healthy colonies, and these were monitored daily at the gross and microscopic level for 40 days. Grossly, corals healed by Day 30, but repigmentation was not evident at the end of the study (40 d). On histology, from Day 8 onwards, tissues at the lesion site were microscopically indistinguishable from adjacent normal tissues with evidence of zooxanthellae in gastrodermis. Inflammation was not evident. P. damicornis manifested a unique mode of regeneration involving projections of cell-covered mesoglea from the surface body wall that anastomosed to form gastrovascular canals.

Functional Attachment of Soft Tissues to Bone: Development, Healing, and Tissue Engineering

PubMed Central

Lu, Helen H.; Thomopoulos, Stavros

2014-01-01

Connective tissues such as tendons or ligaments attach to bone across a multitissue interface with spatial gradients in composition, structure, and mechanical properties. These gradients minimize stress concentrations and mediate load transfer between the soft and hard tissues. Given the high incidence of tendon and ligament injuries and the lack of integrative solutions for their repair, interface regeneration remains a significant clinical challenge. This review begins with a description of the developmental processes and the resultant structure-function relationships that translate into the functional grading necessary for stress transfer between soft tissue and bone. It then discusses the interface healing response, with a focus on the influence of mechanical loading and the role of cell-cell interactions. The review continues with a description of current efforts in interface tissue engineering, highlighting key strategies for the regeneration of the soft tissue–to-bone interface, and concludes with a summary of challenges and future directions. PMID:23642244

Information generation and processing systems that regulate periodontal structure and function.

PubMed

Bartold, P Mark; McCulloch, Christopher A

2013-10-01

The periodontium is a very dynamic organ that responds rapidly to mechanical and chemical stimuli. It is very complex in that it is composed of two hard tissues (cementum and bone) and two soft connective tissues (periodontal ligament and gingiva). Together these tissues are defined by the molecules expressed by the resident periodontal cells in each compartment and this determines not only the structure and function of the periodontium but also how it responds to infection and inflammation. The biological activity of these molecules is tightly regulated in time and space to preserve tissue homeostasis, influence inflammatory responses and participate in tissue regeneration. In this issue of Periodontology 2000 we explore new experimental approaches and data sets which help to understand the molecules and cells that regulate tissue form and structure in health, disease and regeneration. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Trends in tissue repair and regeneration.

PubMed

Galliot, Brigitte; Crescenzi, Marco; Jacinto, Antonio; Tajbakhsh, Shahragim

2017-02-01

The 6th EMBO conference on the Molecular and Cellular Basis of Regeneration and Tissue Repair took place in Paestum (Italy) on the 17th-21st September, 2016. The 160 scientists who attended discussed the importance of cellular and tissue plasticity, biophysical aspects of regeneration, the diverse roles of injury-induced immune responses, strategies to reactivate regeneration in mammals, links between regeneration and ageing, and the impact of non-mammalian models on regenerative medicine. © 2017. Published by The Company of Biologists Ltd.

Behaviour of telomere and telomerase during aging and regeneration in zebrafish.

PubMed

Anchelin, Monique; Murcia, Laura; Alcaraz-Pérez, Francisca; García-Navarro, Esther M; Cayuela, María L

2011-02-09

Telomere length and telomerase activity are important factors in the pathobiology of human diseases. Age-related diseases and premature aging syndromes are characterized by short telomeres, which can compromise cell viability, whereas tumour cells can prevent telomere loss by aberrantly upregulating telomerase. The zebrafish (Danio rerio) offers multiple experimental manipulation advantages over other vertebrate models and, therefore, it has been recently considered as a potential model for aging, cancer, and regeneration studies. However, it has only partially been exploited to shed light on these fundamental biological processes. The aim of this study was, therefore, to investigate telomere length and telomerase expression and activity in different strains of zebrafish obtained from different stock centres to determine whether they undergo any changes during aging and regeneration. We found that although both telomerase expression and telomere length increased from embryo to adulthood stages, they drastically declined in aged fish despite telomerase activity was detected in different tissues of old fish. In addition, we observed a weaker upregulation of telomerase expression in regenerating fins of old fish, which well correlates with their impaired regeneration capacity. Strikingly, telomeres were elongated or maintained during the fin regeneration process at all ages and after repeated amputations, likely to support high cell proliferation rates. We conclude that the expression of telomerase and telomere length are closely related during the entire life cycle of the fish and that these two parameters can be used as biomarkers of aging in zebrafish. Our results also reveal a direct relationship between the expression of telomerase, telomere length and the efficiency of tissue regeneration.

The Hippo pathway in tissue homeostasis and regeneration.

PubMed

Wang, Yu; Yu, Aijuan; Yu, Fa-Xing

2017-05-01

While several organs in mammals retain partial regenerative capability following tissue damage, the underlying mechanisms remain unclear. Recently, the Hippo signaling pathway, better known for its function in organ size control, has been shown to play a pivotal role in regulating tissue homeostasis and regeneration. Upon tissue injury, the activity of YAP, the major effector of the Hippo pathway, is transiently induced, which in turn promotes expansion of tissue-resident progenitors and facilitates tissue regeneration. In this review, with a general focus on the Hippo pathway, we will discuss its major components, functions in stem cell biology, involvement in tissue regeneration in different organs, and potential strategies for developing Hippo pathway-targeted regenerative medicines.

Transcriptional regulators in the Hippo signaling pathway control organ growth in Xenopus tadpole tail regeneration.

PubMed

Hayashi, Shinichi; Ochi, Haruki; Ogino, Hajime; Kawasumi, Aiko; Kamei, Yasuhiro; Tamura, Koji; Yokoyama, Hitoshi

2014-12-01

The size and shape of tissues are tightly controlled by synchronized processes among cells and tissues to produce an integrated organ. The Hippo signaling pathway controls both cell proliferation and apoptosis by dual signal-transduction states regulated through a repressive kinase cascade. Yap1 and Tead, transcriptional regulators that act downstream of the Hippo signaling kinase cascade, have essential roles in regulating cell proliferation. In amphibian limb or tail regeneration, the local tissue outgrowth terminates when the correct size is reached, suggesting that organ size is strictly controlled during epimorphic organ-level regeneration. We recently demonstrated that Yap1 is required for the regeneration of Xenopus tadpole limb buds (Hayashi et al., 2014, Dev. Biol. 388, 57-67), but the molecular link between the Hippo pathway and organ size control in vertebrate epimorphic regeneration is not fully understood. To examine the requirement of Hippo pathway transcriptional regulators in epimorphic regeneration, including organ size control, we inhibited these regulators during Xenopus tadpole tail regeneration by overexpressing a dominant-negative form of Yap (dnYap) or Tead4 (dnTead4) under a heat-shock promoter in transgenic animal lines. Each inhibition resulted in regeneration defects accompanied by reduced cell mitosis and increased apoptosis. Single-cell gene manipulation experiments indicated that Tead4 cell-autonomously regulates the survival of neural progenitor cells in the regenerating tail. In amphibians, amputation at the proximal level of the tail (deep amputation) results in faster regeneration than that at the distal level (shallow amputation), to restore the original-sized tail with similar timing. However, dnTead4 overexpression abolished the position-dependent differential growth rate of tail regeneration. These results suggest that the transcriptional regulators in the Hippo pathway, Tead4 and Yap1, are required for general vertebrate epimorphic regeneration as well as for organ size control in appendage regeneration. In regenerative medicine, these findings should contribute to the development of three-dimensional organs with the correct size for a patient's body. Copyright © 2014 Elsevier Inc. All rights reserved.

Stem cell-dependent formation of a functional anterior regeneration pole in planarians requires Zic and Forkhead transcription factors.

PubMed

Vogg, Matthias C; Owlarn, Suthira; Pérez Rico, Yuvia A; Xie, Jianlei; Suzuki, Yoko; Gentile, Luca; Wu, Wei; Bartscherer, Kerstin

2014-06-15

Planarians can regenerate their head within days. This process depends on the direction of adult stem cells to wound sites and the orchestration of their progenitors to commit to appropriate lineages and to arrange into patterned tissues. We identified a zinc finger transcription factor, Smed-ZicA, as a downstream target of Smed-FoxD, a Forkhead transcription factor required for head regeneration. Smed-zicA and Smed-FoxD are co-expressed with the Wnt inhibitor notum and the Activin inhibitor follistatin in a cluster of cells at the anterior-most tip of the regenerating head - the anterior regeneration pole - and in surrounding stem cell progeny. Depletion of Smed-zicA and Smed-FoxD by RNAi abolishes notum and follistatin expression at the pole and inhibits head formation downstream of initial polarity decisions. We suggest a model in which ZicA and FoxD transcription factors synergize to control the formation of Notum- and Follistatin-producing anterior pole cells. Pole formation might constitute an early step in regeneration, resulting in a signaling center that orchestrates cellular events in the growing tissue. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Macrophages are required to coordinate mouse digit tip regeneration.

PubMed

Simkin, Jennifer; Sammarco, Mimi C; Marrero, Luis; Dawson, Lindsay A; Yan, Mingquan; Tucker, Catherine; Cammack, Alex; Muneoka, Ken

2017-11-01

In mammals, macrophages are known to play a major role in tissue regeneration. They contribute to inflammation, histolysis, re-epithelialization, revascularization and cell proliferation. Macrophages have been shown to be essential for regeneration in salamanders and fish, but their role has not been elucidated in mammalian epimorphic regeneration. Here, using the regenerating mouse digit tip as a mammalian model, we demonstrate that macrophages are essential for the regeneration process. Using cell-depletion strategies, we show that regeneration is completely inhibited; bone histolysis does not occur, wound re-epithelialization is inhibited and the blastema does not form. Although rescue of epidermal wound closure in the absence of macrophages promotes blastema accumulation, it does not rescue cell differentiation, indicating that macrophages play a key role in the redifferentiation of the blastema. We provide additional evidence that although bone degradation is a component, it is not essential to the overall regenerative process. These findings show that macrophages play an essential role in coordinating the epimorphic regenerative response in mammals. © 2017. Published by The Company of Biologists Ltd.

Human Periodontal Cells Demonstrate Osteoblast-Like and Fibroblast-Like Characteristics in Tissue Culture

DTIC Science & Technology

1989-05-05

gingiva and periodontal ligament emphasizes similarities between the connective tissues of gingiva and periodontal ligament. Possible regeneration of...Clinicians and researchers gradually realized the importance of periodontal ligament granulation tissue in periodontal regeneration (Melcher, 1976...isolated osseous defects. The guided tissue regeneration technique uses membrane filters to isolate healing periodontal defects from gingival connective

Tissue Engineering and Regenerative Repair in Wound Healing

PubMed Central

Hu, Michael S.; Maan, Zeshaan N.; Wu, Jen-Chieh; Rennert, Robert C.; Hong, Wan Xing; Lai, Tiffany S.; Cheung, Alexander T. M.; Walmsley, Graham G.; Chung, Michael T.; McArdle, Adrian; Longaker, Michael T.; Lorenz, H. Peter

2014-01-01

Wound healing is a highly evolved defense mechanism against infection and further injury. It is a complex process involving multiple cell types and biological pathways. Mammalian adult cutaneous wound healing is mediated by a fibroproliferative response leading to scar formation. In contrast, early to mid-gestational fetal cutaneous wound healing is more akin to regeneration and occurs without scar formation. This early observation has led to extensive research seeking to unlock the mechanism underlying fetal scarless regenerative repair. Building upon recent advances in biomaterials and stem cell applications, tissue engineering approaches are working towards a recapitulation of this phenomenon. In this review, we describe the elements that distinguish fetal scarless and adult scarring wound healing, and discuss current trends in tissue engineering aimed at achieving scarless tissue regeneration. PMID:24788648

Identification of differentially expressed lncRNAs involved in transient regeneration of the neonatal C57BL/6J mouse heart by next-generation high-throughput RNA sequencing.

PubMed

Chen, Yu-Mei; Li, Hua; Fan, Yi; Zhang, Qi-Jun; Li, Xing; Wu, Li-Jie; Chen, Zi-Jie; Zhu, Chun; Qian, Ling-Mei

2017-04-25

Previous studies have shown that mammalian cardiac tissue has a regenerative capacity. Remarkably, neonatal mice can regenerate their cardiac tissue for up to 6 days after birth, but this capacity is lost by day 7. In this study, we aimed to explore the expression pattern of long noncoding RNA (lncRNA) during this period and examine the mechanisms underlying this process. We found that 685 lncRNAs and 1833 mRNAs were differentially expressed at P1 and P7 by the next-generation high-throughput RNA sequencing. The coding genes associated with differentially expressed lncRNAs were mainly involved in metabolic processes and cell proliferation, and also were potentially associated with several key regeneration signalling pathways, including PI3K-Akt, MAPK, Hippo and Wnt. In addition, we identified some correlated targets of highly-dysregulated lncRNAs such as Igfbp3, Trnp1, Itgb6, and Pim3 by the coding-noncoding gene co-expression network. These data may offer a reference resource for further investigation about the mechanisms by which lncRNAs regulate cardiac regeneration.

Lessons from (patho)physiological tissue stiffness and their implications for drug screening, drug delivery and regenerative medicine.

PubMed

Chen, Wen Li Kelly; Simmons, Craig A

2011-04-30

Diseased tissues are noted for their compromised mechanical properties, which contribute to organ failure; regeneration entails restoration of tissue structure and thereby functions. Thus, the physical signature of a tissue is closely associated with its biological function. In this review, we consider a mechanics-centric view of disease and regeneration by drawing parallels between in vivo tissue-level observations and corroborative cellular evidence in vitro to demonstrate the importance of the mechanical stiffness of the extracellular matrix in these processes. This is not intended to devalue the importance of biochemical signaling; in fact, as we discuss, many mechanical stiffness-driven processes not only require cooperation with biochemical cues, but they ultimately converge at common signaling cascades to influence cell and tissue function in an integrative manner. The study of how physical and biochemical signals collectively modulate cell function not only brings forth a more holistic understanding of cell (patho)biology, but it also creates opportunities to control material properties to improve culture platforms for research and drug screening and aid in the rationale design of biomaterials for molecular therapy and tissue engineering applications. Copyright © 2011 Elsevier B.V. All rights reserved.

Epimorphic regeneration approach to tissue replacement in adult mammals

USDA-ARS?s Scientific Manuscript database

Urodeles and fetal mammals are capable of impressive epimorphic regeneration in a variety of tissues, whereas the typical default response to injury in adult mammals consists of inflammation and scar tissue formation. One component of epimorphic regeneration is the recruitment of resident progenitor...

Dental Pulp and Dentin Tissue Engineering and Regeneration – Advancement and Challenge

PubMed Central

Huang, George T.-J.

2012-01-01

Hard tissue is difficult to repair especially dental structures. Tooth enamel is incapable of self-repairing whereas dentin and cememtum can regenerate with limited capacity. Enamel and dentin are commonly under the attack by caries. Extensive forms of caries destroy enamel and dentin and can lead to dental pulp infection. Entire pulp amputation followed by the pulp space disinfection and filled with an artificial rubber-like material is employed to treat the infection --commonly known as root canal or endodontic therapy. Regeneration of dentin relies on having vital pulps; however, regeneration of pulp tissue has been difficult as the tissue is encased in dentin without collateral blood supply except from the root apical end. With the advent of modern tissue engineering concept and the discovery of dental stem cells, regeneration of pulp and dentin has been tested. This article will review the recent endeavor on pulp and dentin tissue engineering and regeneration. The prospective outcome of the current advancement and challenge in this line of research will be discussed. PMID:21196351

The Modulatable Stem Cell Niche: Tissue Interactions during Hair and Feather Follicle Regeneration.

PubMed

Chen, Chih-Chiang; Plikus, Maksim V; Tang, Pin-Chi; Widelitz, Randall B; Chuong, Cheng Ming

2016-04-10

Hair and feathers are unique because (1) their stem cells are contained within a follicle structure, (2) they undergo cyclic regeneration repetitively throughout life, (3) regeneration occurs physiologically in healthy individuals and (4) regeneration is also induced in response to injury. Precise control of this cyclic regeneration process is essential for maintaining the homeostasis of living organisms. While stem cells are regulated by the intra-follicle-adjacent micro-environmental niche, this niche is also modulated dynamically by extra-follicular macro-environmental signals, allowing stem cells to adapt to a larger changing environment and physiological needs. Here we review several examples of macro-environments that communicate with the follicles: intradermal adipose tissue, innate immune system, sex hormones, aging, circadian rhythm and seasonal rhythms. Related diseases are also discussed. Unveiling the mechanisms of how stem cell niches are modulated provides clues for regenerative medicine. Given that stem cells are hard to manipulate, focusing translational therapeutic applications at the environments appears to be a more practical approach. Copyright © 2015 Elsevier Ltd. All rights reserved.

[New challenge of tissue repair and regenerative medicine: to achieve a perfect repair and regeneration of multiple tissues in wound sites].

PubMed

Fu, X B

2016-01-01

Great achievements in the study of tissue repair and regeneration have been made, and many of these successes have been shown to be beneficial to the patients in recent years. However, perfect tissue repair and regeneration of damaged tissues and organs remain to be great challenges in the management of trauma and diseases. Based on the progress in developmental biology in animals and advances in stem cell biology, it is possible to attain the aim of perfect repair and regeneration by means of somatic cell reprogramming and different inducing techniques.

Cartilage and bone cells do not participate in skeletal regeneration in Ambystoma mexicanum limbs.

PubMed

McCusker, Catherine D; Diaz-Castillo, Carlos; Sosnik, Julian; Q Phan, Anne; Gardiner, David M

2016-08-01

The Mexican Axolotl is one of the few tetrapod species that is capable of regenerating complete skeletal elements in injured adult limbs. Whether the skeleton (bone and cartilage) plays a role in the patterning and contribution to the skeletal regenerate is currently unresolved. We tested the induction of pattern formation, the effect on cell proliferation, and contributions of skeletal tissues (cartilage, bone, and periosteum) to the regenerating axolotl limb. We found that bone tissue grafts from transgenic donors expressing GFP fail to induce pattern formation and do not contribute to the newly regenerated skeleton. Periosteum tissue grafts, on the other hand, have both of these activities. These observations reveal that skeletal tissue does not contribute to the regeneration of skeletal elements; rather, these structures are patterned by and derived from cells of non-skeletal connective tissue origin. Copyright © 2016 Elsevier Inc. All rights reserved.

A cellular, molecular, and pharmacological basis for appendage regeneration in mice

PubMed Central

Leung, Thomas H.; Snyder, Emily R.; Liu, Yinghua; Wang, Jing; Kim, Seung K.

2015-01-01

Regenerative medicine aims to restore normal tissue architecture and function. However, the basis of tissue regeneration in mammalian solid organs remains undefined. Remarkably, mice lacking p21 fully regenerate injured ears without discernable scarring. Here we show that, in wild-type mice following tissue injury, stromal-derived factor-1 (Sdf1) is up-regulated in the wound epidermis and recruits Cxcr4-expressing leukocytes to the injury site. In p21-deficient mice, Sdf1 up-regulation and the subsequent recruitment of Cxcr4-expressing leukocytes are significantly diminished, thereby permitting scarless appendage regeneration. Lineage tracing demonstrates that this regeneration derives from fate-restricted progenitor cells. Pharmacological or genetic disruption of Sdf1–Cxcr4 signaling enhances tissue repair, including full reconstitution of tissue architecture and all cell types. Our findings identify signaling and cellular mechanisms underlying appendage regeneration in mice and suggest new therapeutic approaches for regenerative medicine. PMID:26494786

The cancer paradigms of mammalian regeneration: can mammals regenerate as amphibians?

PubMed

Sarig, Rachel; Tzahor, Eldad

2017-04-01

Regeneration in mammals is restricted to distinct tissues and occurs mainly by expansion and maturation of resident stem cells. During regeneration, even subtle mutations in the proliferating cells may cause a detrimental effect by eliciting abnormal differentiation or malignant transformation. Indeed, cancer in mammals has been shown to arise through deregulation of stem cells maturation, which often leads to a differentiation block and cell transformation. In contrast, lower organisms such as amphibians retain a remarkable regenerative capacity in various organs, which occurs via de- and re-differentiation of mature cells. Interestingly, regenerating amphibian cells are highly resistant to oncogenic transformation. Therapeutic approaches to improve mammalian regeneration mainly include stem-cell transplantations; but, these have proved unsuccessful in non-regenerating organs such as the heart. A recently developed approach is to induce de-differentiation of mature cardiomyocytes using factors that trigger their re-entry into the cell cycle. This novel approach raises numerous questions regarding the balance between transformation and regeneration induced by de-differentiation of mature mammalian somatic cells. Can this balance be controlled artificially? Do de-differentiated cells acquire the protection mechanisms seen in regenerating cells of lower organisms? Is this model unique to the cardiac tissue, which rarely develops tumors? This review describes regeneration processes in both mammals and lower organisms and, particularly, the ability of regenerating cells to avoid transformation. By comparing the characteristics of mammalian embryonic and somatic cells, we discuss therapeutic strategies of using various cell populations for regeneration. Finally, we describe a novel cardiac regeneration approach and its implications for regenerative medicine. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Exploring the potential of polyurethane-based soft foam as cell-free scaffold for soft tissue regeneration.

PubMed

Gerges, Irini; Tamplenizza, Margherita; Martello, Federico; Recordati, Camilla; Martelli, Cristina; Ottobrini, Luisa; Tamplenizza, Mariacaterina; Guelcher, Scott A; Tocchio, Alessandro; Lenardi, Cristina

2018-06-01

Reconstructive treatment after trauma and tumor resection would greatly benefit from an effective soft tissue regeneration. The use of cell-free scaffolds for adipose tissue regeneration in vivo is emerging as an attractive alternative to tissue-engineered constructs, since this approach avoids complications due to cell manipulation and lack of synchronous vascularization. In this study, we developed a biodegradable polyurethane-based scaffold for soft tissue regeneration, characterized by an exceptional combination between softness and resilience. Exploring the potential as a cell-free scaffold required profound understanding of the impact of its intrinsic physico-chemical properties on the biological performance in vivo. We investigated the effect of the scaffold's hydrophilic character, degradation kinetics, and internal morphology on (i) the local inflammatory response and activation of MGCs (foreign body response); (ii) its ability to promote rapid vascularisation, cell infiltration and migration through the scaffold over time; and (iii) the grade of maturation of the newly formed tissue into vascularized soft tissue in a murine model. The study revealed that soft tissue regeneration in vivo proceeded by gradual infiltration of undifferentiated mesenchymal cells though the periphery toward the center of the scaffold, where the rapid formation of a functional and well-formed vascular network supported cell viability overtime. Exploring the potential of polyurethane-based soft foam as cell-free scaffold for soft tissue regeneration. In this work, we address the unmet need for synthetic functional soft tissue substitutes that provide adequate biological and mechanical support to soft tissue. We developed a series of flexible cross-linked polyurethane copolymer scaffolds with remarkable fatigue-resistance and tunable physico-chemical properties for soft tissue regeneration in vivo. Accordingly, we could extend the potential of this class of biomaterials, which was so far confined for bone and osteochondral tissue regeneration, to other types of connective tissue. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Advanced Engineering Strategies for Periodontal Complex Regeneration.

PubMed

Park, Chan Ho; Kim, Kyoung-Hwa; Lee, Yong-Moo; Seol, Yang-Jo

2016-01-18

The regeneration and integration of multiple tissue types is critical for efforts to restore the function of musculoskeletal complex. In particular, the neogenesis of periodontal constructs for systematic tooth-supporting functions is a current challenge due to micron-scaled tissue compartmentalization, oblique/perpendicular orientations of fibrous connective tissues to the tooth root surface and the orchestration of multiple regenerated tissues. Although there have been various biological and biochemical achievements, periodontal tissue regeneration remains limited and unpredictable. The purpose of this paper is to discuss current advanced engineering approaches for periodontal complex formations; computer-designed, customized scaffolding architectures; cell sheet technology-based multi-phasic approaches; and patient-specific constructs using bioresorbable polymeric material and 3-D printing technology for clinical application. The review covers various advanced technologies for periodontal complex regeneration and state-of-the-art therapeutic avenues in periodontal tissue engineering.

Revitalization of biostatic tissue allografts: new perspectives in tissue transplantology.

PubMed

Olender, E; Uhrynowska-Tyszkiewicz, I; Kaminski, A

2011-10-01

Biostatic (nonvital) tissue allografts have been used for temporary replacement as well as to trigger, stimulate, and ensure space for the regeneration of a recipient's own tissues. Examples of biostatic allografts routinely used in clinic are bone, tendons, skin, and amniotic membrane. A characteristic feature of biostatic allografts is the lack of living cells. In the recipient's body, biostatic allografts function as scaffolds as well as sources of growth, differentiation, and chemotactic factors. After implantation, recipient cells migrate onto the graft, colonize it, and initiate synthesis of extracellular matrix, thereby regenerating the structure of the lost or damaged tissue. The allograft gradually degrades before being remodeled and substituted by the recipient's new tissue. However, this process is not always effective due to a lack of reaction by recipient cells. New concepts have proposed seeding recipient cells onto the allograft prior to implantation, that is, biostatic allografts that are revitalized ex vivo. The aim of this presentation was to review scientific publications to provide essential information on the revitalization of biostatic allografts, as a rising trend in tissue transplantology. Biostatic allografts show the following advantages: they are human-derived, nontoxic, biocompatible, and, in some cases, already display the desired shape. The process of introducing cells into the biostatic graft is described as "revitalization." The cells used in the process are recipient autologous elements that are either differentiated or progenitor elements. Cells are seeded onto the graft directly after retrieval or after propagation in culture. Revitalized biostatic allografts can be used orthotopically for the regeneration of the same tissue they have been retrieved from or heterotopically wherein the graft retrieved from a different tissue is used as a carrier for cells typical for the tissue to be regenerated. Examples of orthotopic use include revitalized trachea, tissue-engineered blood vessels, urinary bladder wall, and revitalized trabecular bone cubes. Examples of heterotopic use include: amniotic membrane as a carrier of limbal stem cells to treat corneal defects, or for chondrocytes to treat articular cartilage defects. Various requirements set by law must be met by tissue banks performing cell seeding of grafts. In Europe, the requirements are described in directives: 2004/23/EC, 2006/17/EC, 2006/86/EC), and in the regulation 2007/1394/EC. Revitalization of biostatic allografts gives new, promising tools for creation of functional parts of organs; brings the methodology used in tissue banks closer to tissue engineering; places the enterprise in the mainstream of advanced biotechnology; allows the full potential of tissue allografts; and opens a new, large area for clinical and laboratory research. Copyright © 2011 Elsevier Inc. All rights reserved.

Network-Based Method for Identifying Co-Regeneration Genes in Bone, Dentin, Nerve and Vessel Tissues

PubMed Central

Pan, Hongying; Zhang, Yu-Hang; Feng, Kaiyan; Kong, XiangYin; Cai, Yu-Dong

2017-01-01

Bone and dental diseases are serious public health problems. Most current clinical treatments for these diseases can produce side effects. Regeneration is a promising therapy for bone and dental diseases, yielding natural tissue recovery with few side effects. Because soft tissues inside the bone and dentin are densely populated with nerves and vessels, the study of bone and dentin regeneration should also consider the co-regeneration of nerves and vessels. In this study, a network-based method to identify co-regeneration genes for bone, dentin, nerve and vessel was constructed based on an extensive network of protein–protein interactions. Three procedures were applied in the network-based method. The first procedure, searching, sought the shortest paths connecting regeneration genes of one tissue type with regeneration genes of other tissues, thereby extracting possible co-regeneration genes. The second procedure, testing, employed a permutation test to evaluate whether possible genes were false discoveries; these genes were excluded by the testing procedure. The last procedure, screening, employed two rules, the betweenness ratio rule and interaction score rule, to select the most essential genes. A total of seventeen genes were inferred by the method, which were deemed to contribute to co-regeneration of at least two tissues. All these seventeen genes were extensively discussed to validate the utility of the method. PMID:28974058

Network-Based Method for Identifying Co- Regeneration Genes in Bone, Dentin, Nerve and Vessel Tissues.

PubMed

Chen, Lei; Pan, Hongying; Zhang, Yu-Hang; Feng, Kaiyan; Kong, XiangYin; Huang, Tao; Cai, Yu-Dong

2017-10-02

Bone and dental diseases are serious public health problems. Most current clinical treatments for these diseases can produce side effects. Regeneration is a promising therapy for bone and dental diseases, yielding natural tissue recovery with few side effects. Because soft tissues inside the bone and dentin are densely populated with nerves and vessels, the study of bone and dentin regeneration should also consider the co-regeneration of nerves and vessels. In this study, a network-based method to identify co-regeneration genes for bone, dentin, nerve and vessel was constructed based on an extensive network of protein-protein interactions. Three procedures were applied in the network-based method. The first procedure, searching, sought the shortest paths connecting regeneration genes of one tissue type with regeneration genes of other tissues, thereby extracting possible co-regeneration genes. The second procedure, testing, employed a permutation test to evaluate whether possible genes were false discoveries; these genes were excluded by the testing procedure. The last procedure, screening, employed two rules, the betweenness ratio rule and interaction score rule, to select the most essential genes. A total of seventeen genes were inferred by the method, which were deemed to contribute to co-regeneration of at least two tissues. All these seventeen genes were extensively discussed to validate the utility of the method.

Connective tissue graft as a biological barrier for guided tissue regeneration in intrabony defects: a histological study in dogs.

PubMed

Ribeiro, Fernando Salimon; Pontes, Ana Emília Farias; Zuza, Elizangela Partata; da Silva, Vanessa Camila; Lia, Raphael Carlos Comelli; Marcantonio Junior, Elcio

2015-06-01

The use of the autogenous periosteal graft as biological barrier has been proposed for periodontal regeneration. The aim of this study was to evaluate the histometric findings of the subepithelial connective tissue graft as barrier in intrabony defects compared to a bioabsorbable membrane. Three-walled intrabony defects were created surgically in the mesial aspect of the right and left maxillary canines in five healthy mongrel dogs. The defects were chronified, and two types of barriers were randomly carried out for guided tissue regeneration in a split-mouth design: the test group with a subepithelial connective tissue graft and the control group with a bioabsorbable membrane. The specimens were processed for histometric analyses of the epithelium (E), connective tissue (CT), newly formed cementum (NC), new bone (NB), and total newly formed tissues (NFT). The test side showed smaller mean of NC (3.6 ± 1.2), NB (2.1 ± 0.7), and NFT (7.7 ± 0.8) than the control group (NC 7.3 ± 0.5; NB 5.3 ± 1.3; NFT 10.1 ± 2.2; P < 0.05). No statistically significant differences were verified for E (test 3.1 ± 2.0; control 2.8 ± 2.1; P > 0.05) and CT (test 2.5 ± 1.1; control 2.0 ± 0.5; P > 0.05) between groups. The bioabsorbable membrane was more effective in maintaining the space for periodontal regeneration than periosteal connective graft when used as barrier. The bioabsorbable membrane showed more favorable regenerative results in intrabony defects in dogs than the subepithelial connective tissue graft as biological barrier.

Biochemical and Biophysical Cues in Matrix Design for Chronic and Diabetic Wound Treatment

PubMed Central

Xiao, Yun; Ahadian, Samad

2017-01-01

Progress in biomaterial science and engineering and increasing knowledge in cell biology have enabled us to develop functional biomaterials providing appropriate biochemical and biophysical cues for tissue regeneration applications. Tissue regeneration is particularly important to treat chronic wounds of people with diabetes. Understanding and controlling the cellular microenvironment of the wound tissue are important to improve the wound healing process. In this study, we review different biochemical (e.g., growth factors, peptides, DNA, and RNA) and biophysical (e.g., topographical guidance, pressure, electrical stimulation, and pulsed electromagnetic field) cues providing a functional and instructive acellular matrix to heal diabetic chronic wounds. The biochemical and biophysical signals generally regulate cell–matrix interactions and cell behavior and function inducing the tissue regeneration for chronic wounds. Some technologies and devices have already been developed and used in the clinic employing biochemical and biophysical cues for wound healing applications. These technologies can be integrated with smart biomaterials to deliver therapeutic agents to the wound tissue in a precise and controllable manner. This review provides useful guidance in understanding molecular mechanisms and signals in the healing of diabetic chronic wounds and in designing instructive biomaterials to treat them. PMID:27405960

Differences in collagen distribution of healthy and regenerated periodontium. Histomorphometric study in dogs.

PubMed

Souza, Sérgio L S; Macedo, Guilherme O; Silveira E Souza, Adriana M M; Taba, Mário; Novaes, Arthur B; Oliver, Constance; Jamur, Maria C; Correa, Vani M A

2013-10-01

Previous studies have shown that there is a relationship between periodontal disease and the distribution of collagen fibers. This study evaluated the distribution of collagen types I and III in regenerated bone and periodontal ligament, comparing them to the tissues near the regenerated area and to the healthy periodontium. In the third (P3) and fourth (P4) mandibular premolars of 5 healthy mongrel dogs, bilaterally, buccal class 2 furcation lesions were surgically created and chronified for 3 weeks. After that, full flaps were elevated and expanded polytetrafluoroethylene (e-PTFE) membranes were adapted, sutured and recovered by the flaps. Two weeks after surgery, two membranes on the same side were removed and the other membranes were removed four weeks after surgery. The dogs were euthanized at 12 weeks following placement of the e-PTFE membranes. P3 and P4 teeth as well as the second premolars (healthy control teeth) and their periodontal tissues were removed and histologically processed for Collagen Quantification (COLQ). The amount of type III collagen was higher in native bone compared to the regenerated area. For periodontal ligament, COLQ for type I collagen showed statistically significant differences (Tukeys's Multiple Comparison, p⟨0.05) between the regenerated groups and the control group. These differences were not found for type III COLQ. There are significant differences in collagen distribution among the regenerated, native and control tissues. Membrane removal 2 or 4 weeks postoperatively did not influence the collagen composition.

Guided Bone Regeneration in Long-Bone Defects with a Structural Hydroxyapatite Graft and Collagen Membrane

DTIC Science & Technology

2013-01-01

Praetorius, F. Guided tissue regeneration using de- gradable and nondegradable membranes in rabbit tibia. Clin Oral Implants Res 4, 172, 1993. 8. Queiroz... Regeneration of periodontal tissues : combinations of barrier membranes and grafting materials–biological foundation and preclinical evi- dence: a...structural graft provides benefits for bone tissue regeneration in terms of early interfacial integration. Introduction The treatment of large-bone defects

Peripheral Nerve Regeneration Strategies: Electrically Stimulating Polymer Based Nerve Growth Conduits

PubMed Central

Anderson, Matthew; Shelke, Namdev B.; Manoukian, Ohan S.; Yu, Xiaojun; McCullough, Louise D.; Kumbar, Sangamesh G.

2017-01-01

Treatment of large peripheral nerve damages ranges from the use of an autologous nerve graft to a synthetic nerve growth conduit. Biological grafts, in spite of many merits, show several limitations in terms of availability and donor site morbidity, and outcomes are suboptimal due to fascicle mismatch, scarring, and fibrosis. Tissue engineered nerve graft substitutes utilize polymeric conduits in conjunction with cues both chemical and physical, cells alone and or in combination. The chemical and physical cues delivered through polymeric conduits play an important role and drive tissue regeneration. Electrical stimulation (ES) has been applied toward the repair and regeneration of various tissues such as muscle, tendon, nerve, and articular tissue both in laboratory and clinical settings. The underlying mechanisms that regulate cellular activities such as cell adhesion, proliferation, cell migration, protein production, and tissue regeneration following ES is not fully understood. Polymeric constructs that can carry the electrical stimulation along the length of the scaffold have been developed and characterized for possible nerve regeneration applications. We discuss the use of electrically conductive polymers and associated cell interaction, biocompatibility, tissue regeneration, and recent basic research for nerve regeneration. In conclusion, a multifunctional combinatorial device comprised of biomaterial, structural, functional, cellular, and molecular aspects may be the best way forward for effective peripheral nerve regeneration. PMID:27278739

Heterochronic parabiosis for the study of the effects of aging on stem cells and their niches

PubMed Central

Conboy, Irina M.; Rando, Thomas A.

2012-01-01

Aging is unmistakable and undeniable in mammals. Interestingly, mice develop cataracts, muscle atrophy, osteoporosis, obesity, diabetes and cognitive deficits after just 2–3 postnatal years, while it takes seven or more decades for the same age-specific phenotypes to develop in humans. Thus, chronological age corresponds differently with biological age in metazoan species and although many theories exist, we do not understand what controls the rate of mammalian aging. One interesting idea is that species-specific rate of aging represents a ratio of tissue attrition to tissue regeneration. Furthermore, current findings suggest that the age-imposed biochemical changes in the niches of tissue stem cells inhibit performance of this regenerative pool, which leads to the decline of tissue maintenance and repair. If true, slowing down stem cell and niche aging, thereby promoting tissue regeneration, could slow down the process of tissue and organismal aging. In this regard, recent studies of heterochronic parabiosis provide important clues as to the mechanisms of stem cell aging and suggest novel strategies for enhancing tissue repair in the old. Here we review current literature on the relationship between the vigor of tissue stem cells and the process of aging, with an emphasis on the rejuvenation of old tissues by the extrinsic modifications of stem cell niches. PMID:22617385

Tissue engineering for clinical applications.

PubMed

Bhatia, Sujata K

2010-12-01

Tissue engineering is increasingly being recognized as a beneficial means for lessening the global disease burden. One strategy of tissue engineering is to replace lost tissues or organs with polymeric scaffolds that contain specialized populations of living cells, with the goal of regenerating tissues to restore normal function. Typical constructs for tissue engineering employ biocompatible and degradable polymers, along with organ-specific and tissue-specific cells. Once implanted, the construct guides the growth and development of new tissues; the polymer scaffold degrades away to be replaced by healthy functioning tissue. The ideal biomaterial for tissue engineering not only defends against disease and supports weakened tissues or organs, it also provides the elements required for healing and repair, stimulates the body's intrinsic immunological and regenerative capacities, and seamlessly interacts with the living body. Tissue engineering has been investigated for virtually every organ system in the human body. This review describes the potential of tissue engineering to alleviate disease, as well as the latest advances in tissue regeneration. The discussion focuses on three specific clinical applications of tissue engineering: cardiac tissue regeneration for treatment of heart failure; nerve regeneration for treatment of stroke; and lung regeneration for treatment of chronic obstructive pulmonary disease. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Axolotl Fibula as a Model for the Induction of Regeneration across Large Segment Defects in Long Bones of the Extremities

PubMed Central

Chen, Xiaoping; Song, Fengyu; Jhamb, Deepali; Li, Jiliang; Bottino, Marco C.; Palakal, Mathew J.; Stocum, David L.

2015-01-01

We tested the ability of the axolotl (Ambystoma mexicanum) fibula to regenerate across segment defects of different size in the absence of intervention or after implant of a unique 8-braid pig small intestine submucosa (SIS) scaffold, with or without incorporated growth factor combinations or tissue protein extract. Fractures and defects of 10% and 20% of the total limb length regenerated well without any intervention, but 40% and 50% defects failed to regenerate after either simple removal of bone or implanting SIS scaffold alone. By contrast, scaffold soaked in the growth factor combination BMP-4/HGF or in protein extract of intact limb tissue promoted partial or extensive induction of cartilage and bone across 50% segment defects in 30%-33% of cases. These results show that BMP-4/HGF and intact tissue protein extract can promote the events required to induce cartilage and bone formation across a segment defect larger than critical size and that the long bones of axolotl limbs are an inexpensive model to screen soluble factors and natural and synthetic scaffolds for their efficacy in stimulating this process. PMID:26098852

Periodontal cell implantation contributes to the regeneration of the periodontium in an indirect way.

PubMed

Yu, Na; Bronckers, Antonius L J J; Oortgiesen, Daniel A W; Yan, Xiangzhen; Jansen, John A; Yang, Fang; Walboomers, X Frank

2015-01-01

Periodontitis is the most common human infectious disease. Regeneration of bone and soft tissue defects after periodontitis remains challenging, although the transplantation of periodontal ligament (PDL) cells seems a liable strategy. However, little is known about the function of PDL cells after transplantation. In the current study, a combination of in vitro coculture systems and in vivo immunohistochemistry (IHC) was used to investigate the role of PDL cells in the regenerative process. First, a coculture method was used, in which mesenchymal cells (representing the host tissue) were brought into direct contact with PDL cells (representing the transplanted cell population). It was found that PDL cells significantly increased mineralized matrix formation and osteocalcin expression, whereas control cells did not. Similar results were obtained when a noncontact coculture system was applied separating PDL and mesenchymal cells. In an in vivo rat model, regeneration of alveolar bone and ligament was seen after PDL cell transplantation. Implanted PDL cells were found clustered along the newly formed tissues. IHC showed enhanced osteopontin expression and gap junction staining in areas neighboring implanted PDL cells. In conclusion, PDL cells enhance periodontal regeneration through a trophic factor stimulating the osteogenic activity of the surrounding host cells.

Low-intensity pulsed ultrasound in dentofacial tissue engineering.

PubMed

Tanaka, Eiji; Kuroda, Shingo; Horiuchi, Shinya; Tabata, Akira; El-Bialy, Tarek

2015-04-01

Oral and maxillofacial diseases affect millions of people worldwide and hence tissue engineering can be considered an interesting and clinically relevant approach to regenerate orofacial tissues after being affected by different diseases. Among several innovations for tissue regeneration, low-intensity pulsed ultrasound (LIPUS) has been used extensively in medicine as a therapeutic, operative, and diagnostic tool. LIPUS is accepted to promote bone fracture repair and regeneration. Furthermore, the effect of LIPUS on soft tissues regeneration has been paid much attention, and many studies have performed to evaluate the potential use of LIPUS to tissue engineering soft tissues. The present article provides an overview about the status of LIPUS stimulation as a tool to be used to enhance regeneration/tissue engineering. This review consists of five parts. Part 1 is a brief introduction of the acoustic description of LIPUS and mechanical action. In Part 2, biological problems in dentofacial tissue engineering are proposed. Part 3 explores biologic mechanisms of LIPUS to cells and tissues in living body. In Part 4, the effectiveness of LIPUS on cell metabolism and tissue regeneration in dentistry are summarized. Finally, Part 5 relates the possibility of clinical application of LIPUS in orthodontics. The present review brings out better understanding of the bioeffect of LIPUS therapy on orofacial tissues which is essential to the successful integration of management remedies for tissue regeneration/engineering. To develop an evidence-based approach to clinical management and treatment of orofacial degenerative diseases using LIPUS, we would like to be in full pursuit of LIPUS biotherapy. Still, there are many challenges for this relatively new strategy, but the up to date achievements using it promises to go far beyond the present possibilities.

Wound repair and regeneration: mechanisms, signaling, and translation.

PubMed

Eming, Sabine A; Martin, Paul; Tomic-Canic, Marjana

2014-12-03

The cellular and molecular mechanisms underpinning tissue repair and its failure to heal are still poorly understood, and current therapies are limited. Poor wound healing after trauma, surgery, acute illness, or chronic disease conditions affects millions of people worldwide each year and is the consequence of poorly regulated elements of the healthy tissue repair response, including inflammation, angiogenesis, matrix deposition, and cell recruitment. Failure of one or several of these cellular processes is generally linked to an underlying clinical condition, such as vascular disease, diabetes, or aging, which are all frequently associated with healing pathologies. The search for clinical strategies that might improve the body's natural repair mechanisms will need to be based on a thorough understanding of the basic biology of repair and regeneration. In this review, we highlight emerging concepts in tissue regeneration and repair, and provide some perspectives on how to translate current knowledge into viable clinical approaches for treating patients with wound-healing pathologies. Copyright © 2014, American Association for the Advancement of Science.

Wound repair and regeneration: Mechanisms, signaling, and translation

PubMed Central

Eming, Sabine A.; Martin, Paul; Tomic-Canic, Marjana

2015-01-01

The cellular and molecular mechanisms underpinning tissue repair and its failure to heal are still poorly understood, and current therapies are limited. Poor wound healing after trauma, surgery, acute illness, or chronic disease conditions affects millions of people worldwide each year and is the consequence of poorly regulated elements of the healthy tissue repair response, including inflammation, angiogenesis, matrix deposition, and cell recruitment. Failure of one or several of these cellular processes is generally linked to an underlying clinical condition, such as vascular disease, diabetes, or aging, which are all frequently associated with healing pathologies. The search for clinical strategies that might improve the body’s natural repair mechanisms will need to be based on a thorough understanding of the basic biology of repair and regeneration. In this review, we highlight emerging concepts in tissue regeneration and repair, and provide some perspectives on how to translate current knowledge into viable clinical approaches for treating patients with wound-healing pathologies. PMID:25473038

Secretomes from bone marrow-derived mesenchymal stromal cells enhance periodontal tissue regeneration.

PubMed

Kawai, Takamasa; Katagiri, Wataru; Osugi, Masashi; Sugimura, Yukiko; Hibi, Hideharu; Ueda, Minoru

2015-04-01

Periodontal tissue regeneration with the use of mesenchymal stromal cells (MSCs) has been regarded as a future cell-based therapy. However, low survival rates and the potential tumorigenicity of implanted MSCs could undermine the efficacy of cell-based therapy. The use of conditioned media from MSCs (MSC-CM) may be a feasible approach to overcome these limitations. The aim of this study was to confirm the effect of MSC-CM on periodontal regeneration. MSC-CM were collected during their cultivation. The concentrations of the growth factors in MSC-CM were measured with the use of enzyme-linked immunoassay. Rat MSCs (rMSCs) and human umbilical vein endothelial cells cultured in MSC-CM were assessed on wound-healing and angiogenesis. The expressions of osteogenetic- and angiogenic-related genes of rMSCs cultured in MSC-CM were quantified by means of real-time reverse transcriptase-polymerase chain reaction analysis. In vivo, periodontal defects were prepared in the rat models and the collagen sponges with MSC-CM were implanted. MSC-CM includes insulin-like growth factor-1, vascular endothelial growth factor, transforming growth factor-β1 and hepatocyte growth factor. In vitro, wound-healing and angiogenesis increased significantly in MSC-CM. The levels of expression of osteogenetic- and angiogenic-related genes were significantly upregulated in rMSCs cultured with MSC-CM. In vivo, in the MSC-CM group, 2 weeks after implantation, immunohistochemical analysis showed several CD31-, CD105-or FLK-1-positive cells occurring frequently. At 4 weeks after implantation, regenerated periodontal tissue was observed in MSC-CM groups. The use of MSC-CM may be an alternative therapy for periodontal tissue regeneration because several cytokines included in MSC-CM will contribute to many processes of complicated periodontal tissue regeneration. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

A mild process to design silk scaffolds with reduced β-sheet structure and various topographies at the nanometer scale.

PubMed

Pei, Yazhen; Liu, Xi; Liu, Shanshan; Lu, Qiang; Liu, Jing; Kaplan, David L; Zhu, Hesun

2015-02-01

Three-dimensional (3-D) porous silk scaffolds with good biocompatibility and minimal immunogenicity show promise in a range of tissue regeneration applications. However, the challenge remains to effectively fabricate their microstructures and mechanical properties to satisfy the specific requirements of different tissues. In this study, silk scaffolds were fabricated to form an extracellular matrix (ECM) mimetic nanofibrous architecture using a mild process. A slowly increasing concentration process was applied to regulate silk self-assembly into nanofibers in aqueous solution. Then glycerol was blended with the nanofiber solution and induced silk crystallization in the lyophilization process, endowing freeze-dried scaffolds with water stability. The glycerol was leached from the scaffolds, leaving a similar porous structure at the micrometer scale but different topographies at the nanoscale. Compared to previous salt-leached and methanol-annealed scaffolds, the present scaffolds showed lower β-sheet content, softer mechanical property and improved cell growth and differentiation behaviors, suggesting their promising future as platforms for controlling stem cell fate and soft tissue regeneration. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Long-Distance Signals Are Required for Morphogenesis of the Regenerating Xenopus Tadpole Tail, as Shown by Femtosecond-Laser Ablation

PubMed Central

Mondia, Jessica P.; Levin, Michael; Omenetto, Fiorenzo G.; Orendorff, Ryan D.; Branch, Mary Rose; Adams, Dany Spencer

2011-01-01

Background With the goal of learning to induce regeneration in human beings as a treatment for tissue loss, research is being conducted into the molecular and physiological details of the regeneration process. The tail of Xenopus laevis tadpoles has recently emerged as an important model for these studies; we explored the role of the spinal cord during tadpole tail regeneration. Methods and Results Using ultrafast lasers to ablate cells, and Geometric Morphometrics to quantitatively analyze regenerate morphology, we explored the influence of different cell populations. For at least twenty-four hours after amputation (hpa), laser-induced damage to the dorsal midline affected the morphology of the regenerated tail; damage induced 48 hpa or later did not. Targeting different positions along the anterior-posterior (AP) axis caused different shape changes in the regenerate. Interestingly, damaging two positions affected regenerate morphology in a qualitatively different way than did damaging either position alone. Quantitative comparison of regenerate shapes provided strong evidence against a gradient and for the existence of position-specific morphogenetic information along the entire AP axis. Conclusions We infer that there is a conduit of morphology-influencing information that requires a continuous dorsal midline, particularly an undamaged spinal cord. Contrary to expectation, this information is not in a gradient and it is not localized to the regeneration bud. We present a model of morphogenetic information flow from tissue undamaged by amputation and conclude that studies of information coming from far outside the amputation plane and regeneration bud will be critical for understanding regeneration and for translating fundamental understanding into biomedical approaches. PMID:21949803

Structural Inheritance of the Actin Cytoskeletal Organization Determines the Body Axis in Regenerating Hydra.

PubMed

Livshits, Anton; Shani-Zerbib, Lital; Maroudas-Sacks, Yonit; Braun, Erez; Keren, Kinneret

2017-02-07

Understanding how mechanics complement bio-signaling in defining patterns during morphogenesis is an outstanding challenge. Here, we utilize the multicellular polyp Hydra to investigate the role of the actomyosin cytoskeleton in morphogenesis. We find that the supra-cellular actin fiber organization is inherited from the parent Hydra and determines the body axis in regenerating tissue segments. This form of structural inheritance is non-trivial because of the tissue folding and dynamic actin reorganization involved. We further show that the emergence of multiple body axes can be traced to discrepancies in actin fiber alignment at early stages of the regeneration process. Mechanical constraints induced by anchoring regenerating Hydra on stiff wires suppressed the emergence of multiple body axes, highlighting the importance of mechanical feedbacks in defining and stabilizing the body axis. Together, these results constitute an important step toward the development of an integrated view of morphogenesis that incorporates mechanics. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Nanomaterials for Craniofacial and Dental Tissue Engineering.

PubMed

Li, G; Zhou, T; Lin, S; Shi, S; Lin, Y

2017-07-01

Tissue engineering shows great potential as a future treatment for the craniofacial and dental defects caused by trauma, tumor, and other diseases. Due to the biomimetic features and excellent physiochemical properties, nanomaterials are of vital importance in promoting cell growth and stimulating tissue regeneration in tissue engineering. For craniofacial and dental tissue engineering, the frequently used nanomaterials include nanoparticles, nanofibers, nanotubes, and nanosheets. Nanofibers are attractive for cell invasion and proliferation because of their resemblance to extracellular matrix and the presence of large pores, and they have been used as scaffolds in bone, cartilage, and tooth regeneration. Nanotubes and nanoparticles improve the mechanical and chemical properties of scaffold, increase cell attachment and migration, and facilitate tissue regeneration. In addition, nanofibers and nanoparticles are also used as a delivery system to carry the bioactive agent in bone and tooth regeneration, have better control of the release speed of agent upon degradation of the matrix, and promote tissue regeneration. Although applications of nanomaterials in tissue engineering remain in their infancy with numerous challenges to face, the current results indicate that nanomaterials have massive potential in craniofacial and dental tissue engineering.

Analysis of the rate of maturogenesis of a traumatized Cvek's stage 3 anterior tooth treated with platelet-rich fibrin as a regenerative tool using three-dimensional cone-beam computed tomography: an original case report.

PubMed

Solomon, Raji Viola; Faizuddin, Umrana; Guniganti, Sushma Shravani; Waghray, Shefali

2015-01-01

Regenerative endodontic procedures are biologically based procedures which deal with the regeneration of pulp-like tissue, more idealistically the pulp-dentin complex. The regeneration of this pulp-dentin complex in an infected necrotic tooth with an open apex is possible only when the canal is effectively disinfected. Though there are various procedures for treating open apex ranging from Ca(OH) 2 apexification, mineral trioxide aggregate apexification and surgical approach, regeneration of tissues has always taken superior hand over the repair of tissues. The mechanics behind the regenerative endodontic procedures is that despite the tooth being necrotic, some pulp tissue can survive apically which under favorable conditions proliferate to aid in the process of regeneration. In the past 2 decades, an increased understanding of the physiological roles of platelets in wound healing and after tissue injury has led to the idea of using platelets as therapeutic tools in the field regenerative endodontics. In the present case report with an open apex, high sterilization protocol is followed using triple antibiotic paste as intra-canal medicament, followed which platelet rich fibrin is used as the regenerative material of choice. Over an 18-month follow-up period, clinically patient is asymptomatic and radiographically there is complete regression of the periapical lesion and initiation of the root end closure.

Instructive Biologic Scaffold for Functional Tissue Regeneration Following Trauma to the Extremities

DTIC Science & Technology

2015-09-01

Award Number: W81XWH-12-2-0128 TITLE: Instructive Biologic Scaffold for Functional Tissue Regeneration Following Trauma to the Extremities...2014 - 29 Aug 2015 4. TITLE AND SUBTITLE Instructive Biologic Scaffold for Functional Tissue Regeneration Following Trauma to the Extremities 5a...effectiveness of a regenerative scaffold for the restoration of functional musculotendinous tissue , including the restoration of blood supply and innervation

Experiment aboard Russian satellite "Foton M2" in 2005: new approaches for study on stimulating effect of space flight on cell proliferation and regeneration in Urodela

NASA Astrophysics Data System (ADS)

Grigoryan, E.; Almeida, E.; Domaratskaya, E.; Tairbekov, M.; Aleinikova, K.; Mitashov, V.

A study on space flight effect upon processes of regeneration is due to the necessity to know their characteristics in animals and human exposed to space and earth conditions shortly after flight Several experiments on the newts performed earlier aboard Russian biosatellites showed that the rate of organ and tissue regeneration in space was greater than that on the ground Space flight effect stimulating regeneration was enduring and apparent not only just after flight but long time later as well This observation found support in studies simulated physiological weightlessness by means of fast-rotating clinostat It was shown also that the higher rate of regeneration was associated with enhanced cell proliferation For instance we found that the number of cells in S-phase in regenerating tissues was significantly greater in space-flown animals than in the ground controls However it was unclear whether cell proliferation stimulation was induced by micro- g per se or by conditions of hyper- g during launching and re-adaptation on the earth Molecular mechanisms underlying the change also remained obscure These issues were addressed by the joint Russian-USA experiment Regeneration performed on Foton-M2 in 2005 In 16- day flight we used two well-known models of regeneration lens regeneration after lensectomy and tail regeneration after amputation in adult newts Pleurodeles walt Urodela In order to evaluate cell proliferative activity in time limits of microgravity influence the original method for in-flight delivering DNA precursor BrdU

Flightless I Expression Enhances Murine Claw Regeneration Following Digit Amputation.

PubMed

Strudwick, Xanthe L; Waters, James M; Cowin, Allison J

2017-01-01

The mammalian digit tip is capable of both reparative and regenerative wound healing dependent on the level of amputation injury. Removal of the distal third of the terminal phalange results in successful regeneration, whereas a more severe, proximal, amputation heals by tissue repair. Flightless I (Flii) is involved in both tissue repair and regeneration. It negatively regulates wound repair but elicits a positive effect in hair follicle regeneration, with Flii overexpression resulting in significantly longer hair fibers. Using a model of digit amputation in Flii overexpressing (FIT) mice, we investigated Flii in digit regeneration. Both wild-type and FIT digits regenerated after distal amputation with newly regenerated FIT claws being significantly longer than intact controls. No regeneration was observed in wild-type mice after severe proximal amputation; however, FIT mice showed significant regeneration of the missing digit. Using a three-dimensional model of nail formation, connective tissue fibroblasts isolated from the mesenchymal tissue surrounding the wild-type and FIT digit tips and cocultured with skin keratinocytes demonstrated aggregate structures resembling rudimentary nail buds only when Flii was overexpressed. Moreover, β-catenin and cyclin D1 expression was maintained in the FIT regenerating germinal matrix suggesting a potential interaction of Flii with Wnt signaling during regeneration. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Conductive Au nanowires regulated by silk fibroin nanofibers

NASA Astrophysics Data System (ADS)

Dong, Bo-Ju; Lu, Qiang

2014-03-01

Conductive Au-biopolymer composites have promising applications in tissue engineering such as nerve tissue regeneration. In this study, silk fibroin nanofibers were formed in aqueous solution by regulating silk self-assembly process and then used as template for Au nanowire fabrication. We performed the synthesis of Au seeds by repeating the seeding cycles for several times in order to increase the density of Au seeds on the nanofibers. After electroless plating, densely decorated Au seeds grew into irregularly shaped particles following silk nanofiber to fill the gaps between particles and finally form uniform continuous nanowires. The conductive property of the Au-silk fibroin nanowires was studied with current-voltage ( I-V) measurement. A typical ohmic behavior was observed, which highlighted their potential applications in nerve tissue regeneration.

Neoblasts and the evolution of whole-body regeneration.

PubMed

Gehrke, Andrew R; Srivastava, Mansi

2016-10-01

The molecular mechanisms underlying whole-body regeneration are best understood in the planarian flatworm Schmidtea mediterranea, where a heterogeneous population of somatic stem cells called neoblasts provides new tissue for regeneration of essentially any missing body part. Studies on Schmidtea have provided a detailed description of neoblasts and their role in regeneration, but comparatively little is known about the evolutionary history of these cells and their underlying developmental programs. Acoels, an understudied group of aquatic worms that are also capable of extensive whole-body regeneration, have arisen as an attractive group to study the evolution of regenerative processes due to their phylogenetically distant position relative to flatworms. Here, we review the phylogenetic distribution of neoblast cells and compare their anatomical locations, transcriptional profiles, and roles during regeneration in flatworms and acoels to understand the evolution of whole-body regeneration. While the general role of neoblasts appears conserved in species separated by 550 million years of evolution, the extrinsic inputs they receive during regeneration can vary, making the distinction between homology and convergence of mechanism unclear. A more detailed understanding of the precise mechanisms behind whole-body regeneration in diverse phyla is necessary to understand the evolutionary history of this powerful process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mechanical Unloading Impairs Keratinocyte Migration and Angiogenesis During Cutaneous Wound Healing

DTIC Science & Technology

2008-02-01

Research, Fort Sam Houston, Texas; and 4Center for Wound Healing and Tissue Regeneration, College of Dentistry , University of Illinois at Chicago... generation of degradative enzymes, additional matrix proteins, and cross- linking of collagen, processes which can continue for years to months following the...tissue repair during normal physiological wound healing (5). In an uncompromised individual, the wound healing process generally proceeds with- out

Bladder tissue regeneration using acellular bi-layer silk scaffolds in a large animal model of augmentation cystoplasty.

PubMed

Tu, Duong D; Chung, Yeun Goo; Gil, Eun Seok; Seth, Abhishek; Franck, Debra; Cristofaro, Vivian; Sullivan, Maryrose P; Di Vizio, Dolores; Gomez, Pablo; Adam, Rosalyn M; Kaplan, David L; Estrada, Carlos R; Mauney, Joshua R

2013-11-01

Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a porcine model of augmentation cystoplasty. Two bi-layer matrix configurations were fabricated by solvent-casting/salt leaching either alone (Group 1) or in combination with silk film casting (Group 2) to yield porous foams buttressed by heterogeneous surface pore occlusions or homogenous silk films, respectively. Bladder augmentation was performed with each scaffold group (6 × 6 cm(2)) in juvenile Yorkshire swine for 3 m of implantation. Augmented animals exhibited high rates of survival (Group 1: 5/6, 83%; Group 2: 4/4, 100%) and voluntary voiding over the course of the study period. Urodynamic evaluations demonstrated mean increases in bladder capacity over pre-operative levels (Group 1: 277%; Group 2: 153%) which exceeded nonsurgical control gains (144%) encountered due to animal growth.In addition, animals augmented with both matrix configurations displayed increases in bladder compliance over pre-operative levels(Group 1: 357%; Group 2: 338%) similar to growth-related elevations observed in non-surgical controls (354%) [corrected]. Gross tissue evaluations revealed that both matrix configurations supported extensive de novo tissue formation throughout the entire original implantation site which exhibited ultimate tensile strength similar to nonsurgical counterparts. Histological and immunohistochemical analyses showed that both implant groups promoted comparable extents of smooth muscle regeneration and contractile protein (α-smooth muscle actin and SM22α) expression within defect sites similar to controls. Parallel evaluations demonstrated the formation of a transitional, multi-layered urothelium with prominent cytokeratin, uroplakin, and p63 protein expression in both matrix groups. De novo innervation and vascularization processes were evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Ex vivo organ bath studies demonstrated that regenerated tissues supported by both silk matrices displayed contractile responses to carbachol, α,β-methylene-ATP, KCl, and electrical field stimulation similar to controls. Our data detail the ability of acellular silk scaffolds to support regeneration of innervated, vascularized smooth muscle and urothelial tissues within 3 m with structural, mechanical, and functional properties comparable to native tissue in a porcine model of bladder repair. © 2013 Elsevier Ltd. All rights reserved.

Chitin Scaffolds in Tissue Engineering

PubMed Central

Jayakumar, Rangasamy; Chennazhi, Krishna Prasad; Srinivasan, Sowmya; Nair, Shantikumar V.; Furuike, Tetsuya; Tamura, Hiroshi

2011-01-01

Tissue engineering/regeneration is based on the hypothesis that healthy stem/progenitor cells either recruited or delivered to an injured site, can eventually regenerate lost or damaged tissue. Most of the researchers working in tissue engineering and regenerative technology attempt to create tissue replacements by culturing cells onto synthetic porous three-dimensional polymeric scaffolds, which is currently regarded as an ideal approach to enhance functional tissue regeneration by creating and maintaining channels that facilitate progenitor cell migration, proliferation and differentiation. The requirements that must be satisfied by such scaffolds include providing a space with the proper size, shape and porosity for tissue development and permitting cells from the surrounding tissue to migrate into the matrix. Recently, chitin scaffolds have been widely used in tissue engineering due to their non-toxic, biodegradable and biocompatible nature. The advantage of chitin as a tissue engineering biomaterial lies in that it can be easily processed into gel and scaffold forms for a variety of biomedical applications. Moreover, chitin has been shown to enhance some biological activities such as immunological, antibacterial, drug delivery and have been shown to promote better healing at a faster rate and exhibit greater compatibility with humans. This review provides an overview of the current status of tissue engineering/regenerative medicine research using chitin scaffolds for bone, cartilage and wound healing applications. We also outline the key challenges in this field and the most likely directions for future development and we hope that this review will be helpful to the researchers working in the field of tissue engineering and regenerative medicine. PMID:21673928

A cellular, molecular, and pharmacological basis for appendage regeneration in mice.

PubMed

Leung, Thomas H; Snyder, Emily R; Liu, Yinghua; Wang, Jing; Kim, Seung K

2015-10-15

Regenerative medicine aims to restore normal tissue architecture and function. However, the basis of tissue regeneration in mammalian solid organs remains undefined. Remarkably, mice lacking p21 fully regenerate injured ears without discernable scarring. Here we show that, in wild-type mice following tissue injury, stromal-derived factor-1 (Sdf1) is up-regulated in the wound epidermis and recruits Cxcr4-expressing leukocytes to the injury site. In p21-deficient mice, Sdf1 up-regulation and the subsequent recruitment of Cxcr4-expressing leukocytes are significantly diminished, thereby permitting scarless appendage regeneration. Lineage tracing demonstrates that this regeneration derives from fate-restricted progenitor cells. Pharmacological or genetic disruption of Sdf1-Cxcr4 signaling enhances tissue repair, including full reconstitution of tissue architecture and all cell types. Our findings identify signaling and cellular mechanisms underlying appendage regeneration in mice and suggest new therapeutic approaches for regenerative medicine. © 2015 Leung et al.; Published by Cold Spring Harbor Laboratory Press.

Live Imaging of Axolotl Digit Regeneration Reveals Spatiotemporal Choreography of Diverse Connective Tissue Progenitor Pools.

PubMed

Currie, Joshua D; Kawaguchi, Akane; Traspas, Ricardo Moreno; Schuez, Maritta; Chara, Osvaldo; Tanaka, Elly M

2016-11-21

Connective tissues-skeleton, dermis, pericytes, fascia-are a key cell source for regenerating the patterned skeleton during axolotl appendage regeneration. This complexity has made it difficult to identify the cells that regenerate skeletal tissue. Inability to identify these cells has impeded a mechanistic understanding of blastema formation. By tracing cells during digit tip regeneration using brainbow transgenic axolotls, we show that cells from each connective tissue compartment have distinct spatial and temporal profiles of proliferation, migration, and differentiation. Chondrocytes proliferate but do not migrate into the regenerate. In contrast, pericytes proliferate, then migrate into the blastema and give rise solely to pericytes. Periskeletal cells and fibroblasts contribute the bulk of digit blastema cells and acquire diverse fates according to successive waves of migration that choreograph their proximal-distal and tissue contributions. We further show that platelet-derived growth factor signaling is a potent inducer of fibroblast migration, which is required to form the blastema. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

A Clinical, Biological, and Biomaterials Perspective into Tendon Injuries and Regeneration

PubMed Central

Walden, Grace; Liao, Xin; Donell, Simon; Raxworthy, Mike J.; Riley, Graham P.

2017-01-01

Tendon injury is common and debilitating, and it is associated with long-term pain and ineffective healing. It is estimated to afflict 25% of the adult population and is often a career-ending disease in athletes and racehorses. Tendon injury is associated with high morbidity, pain, and long-term suffering for the patient. Due to the low cellularity and vascularity of tendon tissue, once damage has occurred, the repair process is slow and inefficient, resulting in mechanically, structurally, and functionally inferior tissue. Current treatment options focus on pain management, often being palliative and temporary and ending in reduced function. Most treatments available do not address the underlying cause of the disease and, as such, are often ineffective with variable results. The need for an advanced therapeutic that addresses the underlying pathology is evident. Tissue engineering and regenerative medicine is an emerging field that is aimed at stimulating the body's own repair system to produce de novo tissue through the use of factors such as cells, proteins, and genes that are delivered by a biomaterial scaffold. Successful tissue engineering strategies for tendon regeneration should be built on a foundation of understanding of the molecular and cellular composition of healthy compared with damaged tendon, and the inherent differences seen in the tissue after disease. This article presents a comprehensive clinical, biological, and biomaterials insight into tendon tissue engineering and regeneration toward more advanced therapeutics. PMID:27596929

A histopathologic evaluation of the Plasma Skin Regeneration System (PSR) versus a standard carbon dioxide resurfacing laser in an animal model.

PubMed

Fitzpatrick, R; Bernstein, E; Iyer, S; Brown, D; Andrews, P; Penny, K

2008-02-01

A variety of high energy, pulsed, and scanned carbon dioxide lasers are available to perform cutaneous resurfacing. Rhytec has developed a device for skin regeneration that utilizes energy delivered via a burst of nitrogen plasma. This study was undertaken to benchmark the energy outputs of the plasma skin regeneration device as compared to an ultra-short pulsed carbon dioxide laser (the control device). The two systems were compared for time to complete healing, and the healing response post-treatment. Three Yucatan mini-pigs were utilized for this study. Following anesthesia, five experimental sites were marked along the skin atop the psoas muscle on each side of the spine. Treatment was applied using either the plasma skin regeneration system or the carbon dioxide laser, with one site remaining untreated as a control. Biopsies were taken from all treatment sites 0, 2, 7, 14, 30, and 60 days following treatment and processed to hematoxylin-eosin staining. Histopathologic examination was performed by observers blinded as to the treatment conditions. Skin treated with the plasma skin regeneration device showed a wider range of tissue effects across the energy settings used as compared to the laser treatment. All treatment sites had clinically regenerated epidermis by 7 days after treatment, with active cellular response below the D/E junction noted at the day 30 time-point at energies ranging from 2 to 4 J. The Rhytec PSR system provides an attractive alternative to standard CO2 laser with good remodeling of tissue architecture. Epidermis regenerated after PSR treatment shows a smoother surface profile than adjacent untreated tissue.

The cellular basis for animal regeneration

PubMed Central

Tanaka, Elly; Reddien, Peter W.

2011-01-01

The ability of animals to regenerate missing parts is a dramatic and poorly understood aspect of biology. The sources of new cells for these regenerative phenomena have been sought for decades. Recent advances involving cell fate tracking in complex tissues have shed new light on the cellular underpinnings of regeneration in Hydra, planarians, zebrafish, Xenopus, and Axolotl. Planarians accomplish regeneration with use of adult pluripotent stem cells, whereas several vertebrates utilize a collection of lineage-restricted progenitors from different tissues. Together, an array of cellular strategies—from pluripotent stem cells to tissue-specific stem cells and dedifferentiation—are utilized for regeneration. PMID:21763617

Cloning and expression profile of FLT3 gene during progenitor cell-dependent liver regeneration.

PubMed

Aydin, Iraz T; Tokcaer, Zeynep; Dalgic, Aydin; Konu, Ozlen; Akcali, Kamil C

2007-12-01

The liver has a unique capacity to regenerate upon exposure to viral infections, toxic reactions and cancer formation. Liver regeneration is a complex phenomenon in which several factors participate during its onset. Cellular proliferation is an important component of this process and the factors that regulate this proliferation have a vital role. FLT3, a well-known hematopoietic stem cell and hepatic lineage surface marker, is involved in proliferative events of hematopoietic stem cells. However, its contribution to liver regeneration is not known. Therefore, the aim of this study was to clone and examine the role of FLT3 during liver regeneration in rats. Partial cDNA of rat homolog of FLT3 gene was cloned from thymus and the tissue specific expression of this gene at mRNA and protein levels was examined by RT-PCR and Western blot. After treating with 2-AAF and performing hepatectomy in rats to induce progenitor-dependent liver regeneration, the mRNA and protein expression profile of FLT3 was investigated by real-time PCR and Western blot during liver regeneration. In addition, cellular localization of FLT3 protein was determined by immunohistochemistry. The results indicated that rat FLT3 cDNA has high homology with mouse and human FLT3 cDNA. It was also found that FLT3 is expressed in most of the rat tissues and during liver regeneration. In addition, its intracellular localization is altered during the late stages of liver regeneration. The FLT3 receptor is activated at the late stages of liver regeneration and participates in the proliferation response that is observed during progenitor-dependent liver regeneration.

ETS transcription factor ETV2/ER71/Etsrp in hematopoietic and vascular development, injury, and regeneration.

PubMed

Zhao, Haiyong; Xu, Canxin; Lee, Tae-Jin; Liu, Fang; Choi, Kyunghee

2017-04-01

The major goal in regenerative medicine is to repair and restore injured, diseased or aged tissue function, thereby promoting general health. As such, the field of regenerative medicine has great translational potential in undertaking many of the health concerns and needs that we currently face. In particular, hematopoietic and vascular systems supply oxygen and nutrients and thus play critical roles in tissue development and tissue regeneration. Additionally, tissue vasculature serves as a tissue stem cell niche and thus contributes to tissue homeostasis. Notably, hematopoietic and vascular systems are sensitive to injury and subject to regeneration. As such, successful hematopoietic and vascular regeneration is prerequisite for efficient tissue repair and organismal survival and health. Recent studies have established that the interplay among the ETS transcription factor ETV2, vascular endothelial growth factor, and its receptor VEGFR2/FLK1 is essential for hematopoietic and vascular development. Emerging studies also support the role of these three factors and possible interplay in hematopoietic and vascular regeneration. Comprehensive understanding of the molecular mechanisms involved in the regulation and function of these three factors may lead to more effective approaches in promoting tissue repair and regeneration. Developmental Dynamics 246:318-327, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Bone Regeneration in Rat Cranium Critical-Size Defects Induced by Cementum Protein 1 (CEMP1)

PubMed Central

Serrano, Janeth; Romo, Enrique; Bermúdez, Mercedes; Narayanan, A. Sampath; Zeichner-David, Margarita; Santos, Leticia; Arzate, Higinio

2013-01-01

Gene therapy approaches to bone and periodontal tissue engineering are being widely explored. While localized delivery of osteogenic factors like BMPs is attractive for promotion of bone regeneration; method of delivery, dosage and side effects could limit this approach. A novel protein, Cementum Protein 1 (CEMP1), has recently been shown to promote regeneration of periodontal tissues. In order to address the possibility that CEMP1 can be used to regenerate other types of bone, experiments were designed to test the effect of hrCEMP1 in the repair/regeneration of a rat calvaria critical-size defect. Histological and microcomputed tomography (µCT) analyses of the calvaria defect sites treated with CEMP1 showed that after 16 weeks, hrCEMP1 is able to induce 97% regeneration of the defect. Furthermore, the density and characteristics of the new mineralized tissues were normal for bone. This study demonstrates that hrCEMP1 stimulates bone formation and regeneration and has therapeutic potential for the treatment of bone defects and regeneration of mineralized tissues. PMID:24265720

Tissue culture of three species of Laurencia complex

NASA Astrophysics Data System (ADS)

Shen, Songdong; Wu, Xunjian; Yan, Binlun; He, Lihong

2010-05-01

To establish a micropropagation system of three Laurencia complex species ( Laurencia okamurai, Laurencia tristicha, and Chondrophycus undulatus) by tissue culture techniques, we studied the regeneration characteristics and optimal culture conditions of axenic algal fragments cultured on solid medium and in liquid medium. Regeneration structures were observed and counted regularly under a reverse microscope to investigate the regeneration process, polarity and optimal illumination, and temperature and salinity levels. The results show that in most cultures of the three species, we obtained bud regeneration on solidified medium with 0.5% agar and in liquid medium. Rhizoid-like regeneration was filamentous and developed from the lower cut surface of fragments in L. okamurai, but was discoid and developed from the apical back side of bud regeneration in L. tristicha and C. undulatus. Regeneration polarity was localized to the apical part of algal fronds in all three species, and on fragments cut from the basal part of algae buds could develop from both the upper and the lower cut surfaces. Buds could develop from both the medullary and the cortical portions in L. okamurai and C. undulatus, while in L. tristicha, buds only emerged from the cortex. The optimal culture conditions for L. okamurai were 4 500 lx, 20°C and 35 (salinity); for C. undulatus, 4 500 lx, 20°C and 30; and for L. tristicha, 4 500 lx, 25°C and 30.

Enhancing nerve regeneration in the peripheral nervous system using polymeric scaffolds, stem cell engineering and nanoparticle delivery system

NASA Astrophysics Data System (ADS)

Sharma, Anup Dutt

Peripheral nerve regeneration is a complex biological process responsible for regrowth of neural tissue following a nerve injury. The main objective of this project was to enhance peripheral nerve regeneration using interdisciplinary approaches involving polymeric scaffolds, stem cell therapy, drug delivery and high content screening. Biocompatible and biodegradable polymeric materials such as poly (lactic acid) were used for engineering conduits with micropatterns capable of providing mechanical support and orientation to the regenerating axons and polyanhydrides for fabricating nano/microparticles for localized delivery of neurotrophic growth factors and cytokines at the site of injury. Transdifferentiated bone marrow stromal cells or mesenchymal stem cells (MSCs) were used as cellular replacements for lost native Schwann cells (SCs) at the injured nerve tissue. MSCs that have been transdifferentiated into an SC-like phenotype were tested as a substitute for the myelinating SCs. Also, genetically modified MSCs were engineered to hypersecrete brain- derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) to secrete therapeutic factors which Schwann cell secrete. To further enhance the regeneration, nerve growth factor (NGF) and interleukin-4 (IL4) releasing polyanhydrides nano/microparticles were fabricated and characterized in vitro for their efficacy. Synergistic use of these proposed techniques was used for fabricating a multifunctional nerve regeneration conduit which can be used as an efficient tool for enhancing peripheral nerve regeneration.

High-Resolution Tissue Doppler Imaging of the Zebrafish Heart During Its Regeneration

PubMed Central

Su, Ta-Han; Shih, Cho-Chiang

2015-01-01

Abstract The human heart cannot regenerate after injury, whereas the adult zebrafish can fully regenerate its heart even after 20% of the ventricle is amputated. Many studies have begun to reveal the cellular and molecular mechanisms underlying this regenerative process, which have exciting implications for human cardiac diseases. However, the dynamic functions of the zebrafish heart during regeneration are not yet understood. This study established a high-resolution echocardiography for tissue Doppler imaging (TDI) of the zebrafish heart to explore the cardiac functions during different regeneration phases. Experiments were performed on AB-line adult zebrafish (n=40) in which 15% of the ventricle was surgically removed. An 80-MHz ultrasound TDI based on color M-mode imaging technology was employed. The cardiac flow velocities and patterns from both the ventricular chamber and myocardium were measured at different regeneration phases relative to the day of amputation. The peak velocities of early diastolic inflow, early diastolic myocardial motion, late diastolic myocardial motion, early diastolic deceleration slope, and heart rate were increased at 3 days after the myocardium amputation, but these parameters gradually returned to close to their baseline values for the normal heart at 7 days after amputation. The peak velocities of late diastolic inflow, ventricular systolic outflow, and systolic myocardial motion did not significantly differ during the heart regeneration. PMID:25517185

Laser-induced modification of structure and shape of cartilage in otolaryngology and orthopaedics

NASA Astrophysics Data System (ADS)

Sobol', E. N.; Baum, O. I.; Omel'chenko, A. I.; Soshnikova, Yu. M.; Yuzhakov, A. V.; Kas'yanenko, E. M.; Tokareva, A. V.; Baskov, A. V.; Svistushkin, V. M.; Selezneva, L. V.; Shekhter, A. B.

2017-11-01

We present the results of basic research in laser modification of tissues in otolaryngology (correcting the shape of nasal septum and larynx cartilages), cosmetology (correcting ear and nose shape), orthopaedics and spinal surgery (treatment of diseases of spine disc and joints). The physical processes and mechanisms of laser-induced relaxation of stresses and regeneration of tissues are considered. New results of studies in this fast-developing field of laser surgery are presented, in particular, the results of laser correction of costal cartilage shape in the process of making implants for the treatment of larynx stenosis and controlled regeneration of the hyaline articular cartilage. Presented at the Fundamentals of Laser Assisted Micro- and Nanotechnologies (FLAMN-2016) International Symposium (Pushkin, Leningrad oblast, 27 June to 1 July 2016).

Chondroitin sulfates do not impede axonal regeneration in goldfish spinal cord.

PubMed

Takeda, Akihito; Okada, Soichiro; Funakoshi, Kengo

2017-10-15

Chondroitin sulfate proteoglycans produced in glial scar tissue are a major inhibitory factor for axonal regeneration after central nervous system injury in mammals. The inhibition is largely due to chondroitin sulfates, whose effects differ according to the sulfation pattern. In contrast to mammals, fish nerves spontaneously regenerate beyond the scar tissue after spinal cord injury, although the mechanisms that allow for axons to pass through the scar are unclear. Here, we used immunohistochemistry to examine the expression of two chondroitin sulfates with different sulfation variants at the lesion site in goldfish spinal cord. The intact spinal cord was immunoreactive for both chondroitin sulfate-A (CS-A) and chondroitin sulfate-C (CS-C), and CS-A immunoreactivity overlapped extensively with glial processes positive for glial fibrillary acidic protein. At 1week after inducing the spinal lesion, CS-A immunoreactivity was observed in the cell bodies and extracellular matrix, as well as in glial processes surrounding the lesion center. At 2weeks after the spinal lesion, regenerating axons entering the lesion center overtook the CS-A abundant area. In contrast, at 1week after lesion induction, CS-C immunoreactivity was significantly decreased, and at 2weeks after lesion induction, CS-C immunoreactivity was observed along the regenerating axons entering the lesion center. The present findings suggest that after spinal cord injury in goldfish, chondroitin sulfate proteoglycans are deposited in the extracellular matrix at the lesion site but do not form an impenetrable barrier to the growth of regenerating axons. Copyright © 2017 Elsevier B.V. All rights reserved.

Adipose tissue-organotypic culture system as a promising model for studying adipose tissue biology and regeneration

PubMed Central

Uchihashi, Kazuyoshi; Aoki, Shigehisa; Sonoda, Emiko; Yamasaki, Fumio; Piao, Meihua; Ootani, Akifumi; Yonemitsu, Nobuhisa; Sugihara, Hajime

2009-01-01

Adipose tissue consists of mature adipocytes, preadipocytes and mesenchymal stem cells (MSCs), but a culture system for analyzing their cell types within the tissue has not been established. We have recently developed “adipose tissue-organotypic culture system” that maintains unilocular structure, proliferative ability and functions of mature adipocytes for a long term, using three-dimensional collagen gel culture of the tissue fragments. In this system, both preadipocytes and MSCs regenerate actively at the peripheral zone of the fragments. Our method will open up a new way for studying both multiple cell types within adipose tissue and the cell-based mechanisms of obesity and metabolic syndrome. Thus, it seems to be a promising model for investigating adipose tissue biology and regeneration. In this article, we introduce adipose tissue-organotypic culture, and propose two theories regarding the mechanism of tissue regeneration that occurs specifically at peripheral zone of tissue fragments in vitro. PMID:19794899

Acoustically-Responsive Scaffolds: Control of Growth Factor Release for Tissue Regeneration Using Ultrasound

NASA Astrophysics Data System (ADS)

Moncion, Alexander

Administration of exogenous growth factors (GFs) is a proposed method of stimulating tissue regeneration. Conventional administration routes, such as at-site or systemic injections, have yielded problems with efficacy and/or safety, thus hindering the translation of GF-based regenerative techniques. Hydrogel scaffolds are commonly used as biocompatible delivery vehicles for GFs. Yet hydrogels do not afford spatial or temporal control of GF release - two critical parameters for tissue regeneration. Controlled delivery of GFs is critical for angiogenesis, which is a crucial process in tissue engineering that provides oxygen and nutrients to cells within an implanted hydrogel scaffold. Angiogenesis requires multiple GFs that are presented with distinct spatial and temporal profiles. Thus, controlled release of GFs with spatiotemporal modulation would significantly improve tissue regeneration by recapitulating endogenous GF presentation. In order to achieve this goal, we have developed acoustically-responsive scaffolds (ARSs), which are fibrin hydrogels doped with sonosensitive perfluorocarbon (PFC) emulsions capable of encapsulating various payloads. Focused, mega-Hertz range, ultrasound (US) can modulate the release of a payload non-invasively and in an on-demand manner from ARSs via physical mechanisms termed acoustic droplet vaporization (ADV) and inertial cavitation (IC). This work presents the relationship between the ADV/IC thresholds and various US and hydrogel parameters. These physical mechanisms were used for the controlled release of fluorescent dextran in vitro and in vivo to determine the ARS and US parameters that yielded optimal payload release. The optimal ARS and US parameters were used to demonstrate the controlled release of basic fibroblast growth factor from an in vivo subcutaneous implant model - leading to enhanced angiogenesis and perfusion. Additionally, different acoustic parameters and PFCs were tested and optimized to demonstrate the controlled release of two encapsulated payloads within an ARS. Overall, ARSs are a promising platform for GF delivery in tissue regeneration applications.

Integrin suppresses neurogenesis and regulates brain tissue assembly in planarian regeneration.

PubMed

Bonar, Nicolle A; Petersen, Christian P

2017-03-01

Animals capable of adult regeneration require specific signaling to control injury-induced cell proliferation, specification and patterning, but comparatively little is known about how the regeneration blastema assembles differentiating cells into well-structured functional tissues. Using the planarian Schmidtea mediterranea as a model, we identify β1-integrin as a crucial regulator of blastema architecture. β1-integrin(RNAi) animals formed small head blastemas with severe tissue disorganization, including ectopic neural spheroids containing differentiated neurons normally found in distinct organs. By mimicking aspects of normal brain architecture but without normal cell-type regionalization, these spheroids bore a resemblance to mammalian tissue organoids synthesized in vitro We identified one of four planarian integrin-alpha subunits inhibition of which phenocopied these effects, suggesting that a specific receptor controls brain organization through regeneration. Neoblast stem cells and progenitor cells were mislocalized in β1-integrin(RNAi) animals without significantly altered body-wide patterning. Furthermore, tissue disorganization phenotypes were most pronounced in animals undergoing brain regeneration and not homeostatic maintenance or regeneration-induced remodeling of the brain. These results suggest that integrin signaling ensures proper progenitor recruitment after injury, enabling the generation of large-scale tissue organization within the regeneration blastema. © 2017. Published by The Company of Biologists Ltd.

Adenovirus-mediated transfer of hepatocyte growth factor gene to human dental pulp stem cells under good manufacturing practice improves their potential for periodontal regeneration in swine.

PubMed

Cao, Yu; Liu, Zhenhai; Xie, Yilin; Hu, Jingchao; Wang, Hua; Fan, Zhipeng; Zhang, Chunmei; Wang, Jingsong; Wu, Chu-Tse; Wang, Songlin

2015-12-15

Periodontitis is one of the most widespread infectious diseases in humans. We previously promoted significant periodontal tissue regeneration in swine models with the transplantation of autologous periodontal ligament stem cells (PDLSCs) and PDLSC sheet. We also promoted periodontal tissue regeneration in a rat model with a local injection of allogeneic bone marrow mesenchymal stem cells. The purpose of the present study is to investigate the roles of the hepatocyte growth factor (HGF) and human dental pulp stem cells (DPSCs) in periodontal tissue regeneration in swine. In the present study, we transferred an adenovirus that carried HGF gene into human DPSCs (HGF-hDPSCs) under good manufacturing practice (GMP) conditions. These cells were then transplanted into a swine model for periodontal regeneration. Twenty miniature pigs were used to generate periodontitis with bone defect of 5 mm in width, 7 mm in length, and 3 mm in depth. After 12 weeks, clinical, radiological, quantitative and histological assessment of regenerated periodontal tissues was performed to compare periodontal regeneration in swine treated with cell implantation. Our study showed that injecting HGF-hDPSCs into this large animal model could significantly improve periodontal bone regeneration and soft tissue healing. A hDPSC or HGF-hDPSC sheet showed superior periodontal tissue regeneration compared to the injection of dissociated cells. However, the sheets required surgical placement; thus, they were suitable for surgically-managed periodontitis treatments. The adenovirus-mediated transfer of the HGF gene markedly decreased hDPSC apoptosis in a hypoxic environment or in serum-free medium, and it increased blood vessel regeneration. This study indicated that HGF-hDPSCs produced under GMP conditions significantly improved periodontal bone regeneration in swine; thus, this method represents a potential clinical application for periodontal regeneration.

zic-1 Expression in Planarian Neoblasts after Injury Controls Anterior Pole Regeneration

PubMed Central

Vásquez-Doorman, Constanza; Petersen, Christian P.

2014-01-01

Mechanisms that enable injury responses to prompt regenerative outgrowth are not well understood. Planarians can regenerate essentially any tissue removed by wounding, even after decapitation, due to robust regulation of adult pluripotent stem cells of the neoblast population. Formation of pole signaling centers involving Wnt inhibitors or Wnt ligands promotes head or tail regeneration, respectively, and this process requires the use of neoblasts early after injury. We used expression profiling of purified neoblasts to identify factors needed for anterior pole formation. Using this approach, we identified zic-1, a Zic-family transcription factor, as transcriptionally activated in a subpopulation of neoblasts near wound sites early in head regeneration. As head regeneration proceeds, the Wnt inhibitor notum becomes expressed in the newly forming anterior pole in zic-1-expressing cells descended from neoblasts. Inhibition of zic-1 by RNAi resulted in a failure to express notum at the anterior pole and to regenerate a head, but did not affect tail regeneration. Both injury and canonical Wnt signaling inhibition are required for zic-1 expression, and double-RNAi experiments suggest zic-1 inhibits Wnt signaling to allow head regeneration. Analysis of neoblast fate determinants revealed that zic-1 controls specification of notum-expressing cells from foxD-expressing neoblasts to form the anterior pole, which organizes subsequent outgrowth. Specialized differentiation programs may in general underlie injury-dependent formation of tissue organizing centers used for regenerative outgrowth. PMID:24992682

An evaluation of a new approach to the regeneration of Helichrysum italicum (Roth) G. Don, and the molecular characterization of the variation among sets of differently derived regenerants.

PubMed

Perrini, Rosaria; Alba, Vittorio; Ruta, Claudia; Morone-Fortunato, Irene; Blanco, Antonio; Montemurro, Cinzia

2009-01-01

A protocol for the induction of regeneration from leaves of Helichrysum italicum was established. Calli were found to form on the basal medium only when it was supplemented with thidiazuron (TDZ) alone or in combination with naphthalene acetic acid (NAA), with a percentage ranking of at least 80%. The hormone-free medium showed the highest percentage of shoot regeneration (62%) even though no callus formed. AFLP markers were employed to verify tissue culture-induced variation in the regenerated plantlets obtained by direct shoot regeneration or the indirect shoot regeneration process (callus formation). Seven out of the eleven AFLP primer pairs yielded polymorphic patterns. The average number of fragments per primer pair was 64.1. Singletons were represented by 12 (2.7%) fragments. Student's T-test was performed both on the average number of shared fragments and on the nucleotide diversity, and no significant statistical difference was observed between the two regeneration treatments.

Regeneration of the anterior cruciate ligament: Current strategies in tissue engineering

PubMed Central

Nau, Thomas; Teuschl, Andreas

2015-01-01

Recent advancements in the field of musculoskeletal tissue engineering have raised an increasing interest in the regeneration of the anterior cruciate ligament (ACL). It is the aim of this article to review the current research efforts and highlight promising tissue engineering strategies. The four main components of tissue engineering also apply in several ACL regeneration research efforts. Scaffolds from biological materials, biodegradable polymers and composite materials are used. The main cell sources are mesenchymal stem cells and ACL fibroblasts. In addition, growth factors and mechanical stimuli are applied. So far, the regenerated ACL constructs have been tested in a few animal studies and the results are encouraging. The different strategies, from in vitro ACL regeneration in bioreactor systems to bio-enhanced repair and regeneration, are under constant development. We expect considerable progress in the near future that will result in a realistic option for ACL surgery soon. PMID:25621217

Effects of umbilical cord tissue mesenchymal stem cells (UCX®) on rat sciatic nerve regeneration after neurotmesis injuries.

PubMed

Gärtner, A; Pereira, T; Armada-da-Silva, Pas; Amado, S; Veloso, Ap; Amorim, I; Ribeiro, J; Santos, Jd; Bárcia, Rn; Cruz, P; Cruz, H; Luís, Al; Santos, Jm; Geuna, S; Maurício, Ac

2014-01-01

Peripheral nerves have the intrinsic capacity of self-regeneration after traumatic injury but the extent of the regeneration is often very poor. Increasing evidence demonstrates that mesenchymal stem/stromal cells (MSCs) may play an important role in tissue regeneration through the secretion of soluble trophic factors that enhance and assist in repair by paracrine activation of surrounding cells. In the present study, the therapeutic value of a population of umbilical cord tissue-derived MSCs, obtained by a proprietary method (UCX(®)), was evaluated on end-to-end rat sciatic nerve repair. Furthermore, in order to promote both, end-to-end nerve fiber contacts and MSC cell-cell interaction, as well as reduce the flush away effect of the cells after administration, a commercially available haemostatic sealant, Floseal(®), was used as vehicle. Both, functional and morphologic recoveries were evaluated along the healing period using extensor postural thrust (EPT), withdrawal reflex latency (WRL), ankle kinematics analysis, and either histological analysis or stereology, in the hyper-acute, acute and chronic phases of healing. The histological analysis of the hyper-acute and acute phase studies revealed that in the group treated with UCX(®) alone the Wallerian degeneration was improved for the subsequent process of regeneration, the fiber organization was higher, and the extent of fibrosis was lower. The chronic phase experimental groups revealed that treatment with UCX(®) induced an increased number of regenerated fibers and thickening of the myelin sheet. Kinematics analysis showed that the ankle joint angle determined for untreated animals was significantly different from any of the treated groups at the instant of initial contact (IC). At opposite toe off (OT) and heel rise (HR), differences were found between untreated animals and the groups treated with either uCx(®) alone or UCX(®) administered with Floseal(®). Overall, the UCX(®) application presented positive effects in functional and morphologic recovery, in both the acute and chronic phases of the regeneration process. Kinematics analysis has revealed positive synergistic effects brought by Floseal(®) as vehicle for MSCs.

Effects of umbilical cord tissue mesenchymal stem cells (UCX®) on rat sciatic nerve regeneration after neurotmesis injuries

PubMed Central

Gärtner, A; Pereira, T; Armada-da-Silva, PAS; Amado, S; Veloso, AP; Amorim, I; Ribeiro, J; Santos, JD; Bárcia, RN; Cruz, P; Cruz, H; Luís, AL; Santos, JM; Geuna, S; Maurício, AC

2014-01-01

Peripheral nerves have the intrinsic capacity of self-regeneration after traumatic injury but the extent of the regeneration is often very poor. Increasing evidence demonstrates that mesenchymal stem/stromal cells (MSCs) may play an important role in tissue regeneration through the secretion of soluble trophic factors that enhance and assist in repair by paracrine activation of surrounding cells. In the present study, the therapeutic value of a population of umbilical cord tissue-derived MSCs, obtained by a proprietary method (UCX®), was evaluated on end-to-end rat sciatic nerve repair. Furthermore, in order to promote both, end-to-end nerve fiber contacts and MSC cell-cell interaction, as well as reduce the flush away effect of the cells after administration, a commercially available haemostatic sealant, Floseal®, was used as vehicle. Both, functional and morphologic recoveries were evaluated along the healing period using extensor postural thrust (EPT), withdrawal reflex latency (WRL), ankle kinematics analysis, and either histological analysis or stereology, in the hyper-acute, acute and chronic phases of healing. The histological analysis of the hyper-acute and acute phase studies revealed that in the group treated with UCX® alone the Wallerian degeneration was improved for the subsequent process of regeneration, the fiber organization was higher, and the extent of fibrosis was lower. The chronic phase experimental groups revealed that treatment with UCX® induced an increased number of regenerated fibers and thickening of the myelin sheet. Kinematics analysis showed that the ankle joint angle determined for untreated animals was significantly different from any of the treated groups at the instant of initial contact (IC). At opposite toe off (OT) and heel rise (HR), differences were found between untreated animals and the groups treated with either uCx® alone or UCX® administered with Floseal®. Overall, the UCX® application presented positive effects in functional and morphologic recovery, in both the acute and chronic phases of the regeneration process. Kinematics analysis has revealed positive synergistic effects brought by Floseal® as vehicle for MSCs. PMID:25075157

Composite cell sheet for periodontal regeneration: crosstalk between different types of MSCs in cell sheet facilitates complex periodontal-like tissue regeneration.

PubMed

Zhang, Hao; Liu, Shiyu; Zhu, Bin; Xu, Qiu; Ding, Yin; Jin, Yan

2016-11-14

Tissue-engineering strategies based on mesenchymal stem cells (MSCs) and cell sheets have been widely used for periodontal tissue regeneration. However, given the complexity in periodontal structure, the regeneration methods using a single species of MSC could not fulfill the requirement for periodontal regeneration. We researched the interaction between the periodontal ligament stem cells (PDLSCs) and jaw bone marrow-derived mesenchymal stem cells (JBMMSCs), and constructed a composite cell sheet comprising both of the above MSCs to regenerate complex periodontium-like structures in nude mice. Our results show that by co-culturing PDLSCs and JBMMSCs, the expressions of bone and extracellular matrix (ECM)-related genes and proteins were significantly improved in both MSCs. Further investigations showed that, compared to the cell sheet using PDLSCs or JBMMSCs, the composite stem cell sheet (CSCS), which comprises these two MSCs, expressed higher levels of bone- and ECM-related genes and proteins, and generated a composite structure more similar to the native periodontal tissue physiologically in vivo. In conclusion, our results demonstrate that the crosstalk between PDLSCs and JBMMSCs in cell sheets facilitate regeneration of complex periodontium-like structures, providing a promising new strategy for physiological and functional regeneration of periodontal tissue.

Magnetic Resonance Imaging Allows the Evaluation of Tissue Damage and Regeneration in a Mouse Model of Critical Limb Ischemia.

PubMed

Zaccagnini, Germana; Palmisano, Anna; Canu, Tamara; Maimone, Biagina; Lo Russo, Francesco M; Ambrogi, Federico; Gaetano, Carlo; De Cobelli, Francesco; Del Maschio, Alessandro; Esposito, Antonio; Martelli, Fabio

2015-01-01

Magnetic resonance imaging (MRI) provides non-invasive, repetitive measures in the same individual, allowing the study of a physio-pathological event over time. In this study, we tested the performance of 7 Tesla multi-parametric MRI to monitor the dynamic changes of mouse skeletal muscle injury and regeneration upon acute ischemia induced by femoral artery dissection. T2-mapping (T2 relaxation time), diffusion-tensor imaging (Fractional Anisotropy) and perfusion by Dynamic Contrast-Enhanced MRI (K-trans) were measured and imaging results were correlated with histological morphometric analysis in both Gastrocnemius and Tibialis anterior muscles. We found that tissue damage positively correlated with T2-relaxation time, while myofiber regeneration and capillary density positively correlated with Fractional Anisotropy. Interestingly, K-trans positively correlated with capillary density. Accordingly, repeated MRI measurements between day 1 and day 28 after surgery in ischemic muscles showed that: 1) T2-relaxation time rapidly increased upon ischemia and then gradually declined, returning almost to basal level in the last phases of the regeneration process; 2) Fractional Anisotropy dropped upon ischemic damage induction and then recovered along with muscle regeneration and neoangiogenesis; 3) K-trans reached a minimum upon ischemia, then progressively recovered. Overall, Gastrocnemius and Tibialis anterior muscles displayed similar patterns of MRI parameters dynamic, with more marked responses and less variability in Tibialis anterior. We conclude that MRI provides quantitative information about both tissue damage after ischemia and the subsequent vascular and muscle regeneration, accounting for the differences between subjects and, within the same individual, between different muscles.

Incorporation of Active DNA/Cationic Polymer Polyplexes into Hydrogel Scaffolds

PubMed Central

Lei, Yuguo; Huang, Suxian; Sharif-Kashani, Pooria; Chen, Yong; Kavehpour, Pirouz; Segura, Tatiana

2010-01-01

The effective and sustained delivery of DNA and siRNAs locally would increase the applicability of gene therapy in tissue regeneration and cancer therapy. One promising approach is to use hydrogel scaffolds to encapsulate and deliver nucleotides in the form of nanoparticles to the disease sites. However, this approach is currently limited by the inability to load concentrated and active gene delivery nanoparticles into the hydrogels due to the severe nanoparticle aggregation during the loading process. Here, we present a process to load concentrated and un-aggregated non-viral gene delivery nanoparticles, using DNA/polyethylene imine (PEI) polyplexes as an example, into neutral polyethylene glycol (PEG), negatively charged hyaluronic acid (HA) and protein fibrin hydrogels crosslinked through various chemistries. The encapsulated polyplexes are highly active both in vitro and in vivo. We believe this process will significantly advance the applications of hydrogel scaffold mediated non-viral gene delivery in tissue regeneration and cancer therapy. PMID:20822811

Anterior Gradient 2 (AGR2) Induced Epidermal Growth Factor Receptor (EGFR) Signaling Is Essential for Murine Pancreatitis-Associated Tissue Regeneration

PubMed Central

Wodziak, Dariusz; Dong, Aiwen; Basin, Michael F.; Lowe, Anson W.

2016-01-01

A recently published study identified Anterior Gradient 2 (AGR2) as a regulator of EGFR signaling by promoting receptor presentation from the endoplasmic reticulum to the cell surface. AGR2 also promotes tissue regeneration in amphibians and fish. Whether AGR2-induced EGFR signaling is essential for tissue regeneration in higher vertebrates was evaluated using a well-characterized murine model for pancreatitis. The impact of AGR2 expression and EGFR signaling on tissue regeneration was evaluated using the caerulein-induced pancreatitis mouse model. EGFR signaling and cell proliferation were examined in the context of the AGR2-/- null mouse or with the EGFR-specific tyrosine kinase inhibitor, AG1478. In addition, the Hippo signaling coactivator YAP1 was evaluated in the context of AGR2 expression during pancreatitis. Pancreatitis-induced AGR2 expression enabled EGFR translocation to the plasma membrane, the initiation of cell signaling, and cell proliferation. EGFR signaling and tissue regeneration were partially inhibited by the tyrosine kinase inhibitor AG1478, but absent in the AGR2-/- null mouse. AG1478-treated and AGR2-/- null mice with pancreatitis died whereas all wild-type controls recovered. YAP1 activation was also dependent on pancreatitis-induced AGR2 expression. AGR2-induced EGFR signaling was essential for tissue regeneration and recovery from pancreatitis. The results establish tissue regeneration as a major function of AGR2-induced EGFR signaling in adult higher vertebrates. Enhanced AGR2 expression and EGFR signaling are also universally present in human pancreatic cancer, which support a linkage between tissue injury, regeneration, and cancer pathogenesis. PMID:27764193

Cells, Scaffolds and Their Interactions in Myocardial Tissue Regeneration.

PubMed

Gorabi, Armita Mahdavi; Tafti, Seyed Hossein Ahmadi; Soleimani, Masoud; Panahi, Yunes; Sahebkar, Amirhossein

2017-08-01

Cardiac regenerative therapy includes several techniques to repair and replace damaged tissues and organs using cells, biomaterials, molecules, or a combination of these factors. Generation of heart muscle is the most important challenge in this field, although it is well known that new advances in stem cell isolation and culture techniques in bioreactors and synthesis of bioactive materials contribute to the creation of cardiac tissue regeneration in vitro. Some investigations in stem cell biology shows that stem cells are an important source for regeneration of heart muscle cells and blood vessels and can thus clinically contribute to the regeneration of damaged heart tissue. The aim of this review was to explain the principles and challenges of myocardial tissue regeneration with an emphasis on stem cells and scaffolds. J. Cell. Biochem. 118: 2454-2462, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Stem cell dynamics in the hair follicle niche

PubMed Central

Rompolas, Panteleimon; Greco, Valentina

2014-01-01

Hair follicles are skin appendages of the mammalian skin that have the ability to periodically and stereotypically regenerate in order to continuously produce new hair over our lifetime. The ability of the hair follicle to regenerate is due to the presence of stem cells that along with other cell populations and non-cellular components, including molecular signals and extracellular material, make up a niche microenvironment. Mounting evidence suggests that the niche is critical for regulating stem cell behavior and thus the process of regeneration. Here we review the literature concerning past and current studies that have utilized mouse genetic models, combined with other approaches to dissect the molecular and cellular composition of the hair follicle niche. We also discuss our current understanding of how stem cells operate within the niche during the process of tissue regeneration and the factors that regulate their behavior. PMID:24361866

Cytoplasmic poly (A)-binding protein critically regulates epidermal maintenance and turnover in the planarian Schmidtea mediterranea.

PubMed

Bansal, Dhiru; Kulkarni, Jahnavi; Nadahalli, Kavana; Lakshmanan, Vairavan; Krishna, Srikar; Sasidharan, Vidyanand; Geo, Jini; Dilipkumar, Shilpa; Pasricha, Renu; Gulyani, Akash; Raghavan, Srikala; Palakodeti, Dasaradhi

2017-09-01

Identifying key cellular events that facilitate stem cell function and tissue organization is crucial for understanding the process of regeneration. Planarians are powerful model system to study regeneration and stem cell (neoblast) function. Here, using planaria, we show that the initial events of regeneration, such as epithelialization and epidermal organization are critically regulated by a novel cytoplasmic poly A-binding protein, SMED-PABPC2. Knockdown of smed-pabpc2 leads to defects in epidermal lineage specification, disorganization of epidermis and ECM, and deregulated wound healing, resulting in the selective failure of neoblast proliferation near the wound region. Polysome profiling suggests that epidermal lineage transcripts, including zfp-1 , are translationally regulated by SMED-PABPC2 . Together, our results uncover a novel role for SMED-PABPC2 in the maintenance of epidermal and ECM integrity, critical for wound healing and subsequent processes for regeneration. © 2017. Published by The Company of Biologists Ltd.

Cytoplasmic poly (A)-binding protein critically regulates epidermal maintenance and turnover in the planarian Schmidtea mediterranea

PubMed Central

Bansal, Dhiru; Kulkarni, Jahnavi; Nadahalli, Kavana; Lakshmanan, Vairavan; Krishna, Srikar; Sasidharan, Vidyanand; Dilipkumar, Shilpa; Gulyani, Akash; Raghavan, Srikala

2017-01-01

Identifying key cellular events that facilitate stem cell function and tissue organization is crucial for understanding the process of regeneration. Planarians are powerful model system to study regeneration and stem cell (neoblast) function. Here, using planaria, we show that the initial events of regeneration, such as epithelialization and epidermal organization are critically regulated by a novel cytoplasmic poly A-binding protein, SMED-PABPC2. Knockdown of smed-pabpc2 leads to defects in epidermal lineage specification, disorganization of epidermis and ECM, and deregulated wound healing, resulting in the selective failure of neoblast proliferation near the wound region. Polysome profiling suggests that epidermal lineage transcripts, including zfp-1, are translationally regulated by SMED-PABPC2. Together, our results uncover a novel role for SMED-PABPC2 in the maintenance of epidermal and ECM integrity, critical for wound healing and subsequent processes for regeneration. PMID:28807897

Injectable Reactive Biocomposites For Bone Healing In Critical-Size Rabbit Calvarial Defects

DTIC Science & Technology

2012-03-29

defects (i.e. be conformable), provide temporary protection to the brain until the bone heals, and enhance tissue regeneration with the delivery of...temporary protection to the brain until the bone heals, and enhance tissue regeneration with the delivery of biologics. In this study, we evaluated the...complex defects (i.e. be conformable), harden to provide temporary protection until tissue remodels (i.e. be settable), and enhance tissue regeneration

Mechanoregulation of Wound Healing and Skin Homeostasis

PubMed Central

Rosińczuk, Joanna; Taradaj, Jakub; Dymarek, Robert; Sopel, Mirosław

2016-01-01

Basic and clinical studies on mechanobiology of cells and tissues point to the importance of mechanical forces in the process of skin regeneration and wound healing. These studies result in the development of new therapies that use mechanical force which supports effective healing. A better understanding of mechanobiology will make it possible to develop biomaterials with appropriate physical and chemical properties used to treat poorly healing wounds. In addition, it will make it possible to design devices precisely controlling wound mechanics and to individualize a therapy depending on the type, size, and anatomical location of the wound in specific patients, which will increase the clinical efficiency of the therapy. Linking mechanobiology with the science of biomaterials and nanotechnology will enable in the near future precise interference in abnormal cell signaling responsible for the proliferation, differentiation, cell death, and restoration of the biological balance. The objective of this study is to point to the importance of mechanobiology in regeneration of skin damage and wound healing. The study describes the influence of rigidity of extracellular matrix and special restrictions on cell physiology. The study also defines how and what mechanical changes influence tissue regeneration and wound healing. The influence of mechanical signals in the process of proliferation, differentiation, and skin regeneration is tagged in the study. PMID:27413744

Induced Pluripotent Stem Cells and Periodontal Regeneration.

PubMed

Du, Mi; Duan, Xuejing; Yang, Pishan

Periodontitis is a chronic inflammatory disease which leads to destruction of both the soft and hard tissues of the periodontium. Tissue engineering is a therapeutic approach in regenerative medicine that aims to induce new functional tissue regeneration via the synergistic combination of cells, biomaterials, and/or growth factors. Advances in our understanding of the biology of stem cells, including embryonic stem cells and mesenchymal stem cells, have provided opportunities for periodontal tissue engineering. However, there remain a number of limitations affecting their therapeutic efficiency. Due to the considerable proliferation and differentiation capacities, recently described induced pluripotent stem cells (iPSCs) provide a new way for cell-based therapies for periodontal regeneration. This review outlines the latest status of periodontal tissue engineering and highlights the potential use of iPSCs in periodontal tissue regeneration.

Decellularized Swine Dental Pulp as a Bioscaffold for Pulp Regeneration

PubMed Central

Hu, Lei; Gao, Zhenhua; Zhu, Zhao; Zhang, Chunmei; Wang, Jinsong

2017-01-01

Endodontic regeneration shows promise in treating dental pulp diseases; however, no suitable scaffolds exist for pulp regeneration. Acellular natural extracellular matrix (ECM) is a favorable scaffold for tissue regeneration since the anatomical structure and ECM of the natural tissues or organs are well-preserved. Xenogeneic ECM is superior to autologous or allogeneic ECM in tissue engineering for its unlimited resources. This study investigated the characteristics of decellularized dental pulp ECM from swine and evaluated whether it could mediate pulp regeneration. Dental pulps were acquired from the mandible anterior teeth of swine 12 months of age and decellularized with 10% sodium dodecyl sulfate (SDS) combined with Triton X-100. Pulp regeneration was conducted by seeding human dental pulp stem cells into decellularized pulp and transplanted subcutaneously into nude mice for 8 weeks. The decellularized pulp demonstrated preserved natural shape and structure without any cellular components. Histological analysis showed excellent ECM preservation and pulp-like tissue, and newly formed mineralized tissues were regenerated after being transplanted in vivo. In conclusion, decellularized swine dental pulp maintains ECM components favoring stem cell proliferation and differentiation, thus representing a suitable scaffold for improving clinical outcomes and functions of teeth with dental pulp diseases. PMID:29387727

Rational design of nanofiber scaffolds for orthopedic tissue repair and regeneration

PubMed Central

Ma, Bing; Xie, Jingwei; Jiang, Jiang; Shuler, Franklin D; Bartlett, David E

2013-01-01

This article reviews recent significant advances in the design of nanofiber scaffolds for orthopedic tissue repair and regeneration. It begins with a brief introduction on the limitations of current approaches for orthopedic tissue repair and regeneration. It then illustrates that rationally designed scaffolds made up of electrospun nanofibers could be a promising solution to overcome the problems that current approaches encounter. The article also discusses the intriguing properties of electrospun nanofibers, including control of composition, structures, orders, alignments and mechanical properties, use as carriers for topical drug and/or gene sustained delivery, and serving as substrates for the regulation of cell behaviors, which could benefit musculoskeletal tissue repair and regeneration. It further highlights a few of the many recent applications of electrospun nanofiber scaffolds in repairing and regenerating various orthopedic tissues. Finally, the article concludes with perspectives on the challenges and future directions for better design, fabrication and utilization of nanofiber scaffolds for orthopedic tissue engineering. PMID:23987110

Heart Repair and Regeneration: Recent Insights from Zebrafish Studies

PubMed Central

Lien, Ching-Ling; Harrison, Michael R.; Tuan, Tai-Lan; Starnes, Vaughn A

2012-01-01

Cardiovascular disease is the leading cause of death in United States and worldwide. Failure to properly repair or regenerate damaged cardiac tissues after myocardial infarction is a major cause of heart failure. In contrast to humans and other mammals, zebrafish hearts regenerate after substantial injury or tissue damage. Here, we review recent progress in studying zebrafish heart regeneration, addressing the molecular and cellular responses in the three tissue layers of the heart: myocardium, epicardium, and endocardium. We also compare different injury models utilized to study zebrafish heart regeneration, and discuss the differences in responses to injury between mammalian and zebrafish hearts. By learning how zebrafish hearts regenerate naturally, we can better design therapeutic strategies for repairing human hearts after myocardial infarction. PMID:22818295

High expression of 23 kDa protein of augmenter of liver regeneration (ALR) in human hepatocellular carcinoma

PubMed Central

Yu, Hai-Ying; Zhu, Man-Hua; Xiang, Dai-Rong; Li, Jun; Sheng, Ji-Fang

2014-01-01

Background Augmenter of liver regeneration (ALR) is an important polypeptide that participates in the process of liver regeneration. Two forms of ALR proteins are expressed in hepatocytes. Previous data have shown that ALR is essential for cell survival and has potential antimetastatic properties in hepatocellular carcinoma (HCC). Aims The study aimed to evaluate the expression levels of two forms of ALR proteins in HCC and their possible significance in HCC development. Methods Balb/c mouse monoclonal antibody against ALR protein was prepared in order to detect the ALR protein in HCC by Western blotting and immunohistochemistry. ALR mRNA expression levels were measured by real-time polymerase chain reaction in HCC tissues and compared to paracancerous liver tissues in 22 HCC patients. Results ALR mRNA expression in HCC liver tissues (1.51×106 copies/μL) was higher than in paracancerous tissues (1.04×104 copies/μL). ALR protein expression was also enhanced in HCC liver tissues. The enhanced ALR protein was shown to be 23 kDa by Western blotting. Immunohistochemical analysis showed that the 23 kDa ALR protein mainly existed in the hepatocyte cytosol. Conclusion The 23 kDa ALR protein was highly expressed in HCC and may play an important role in hepatocarcinogenesis. PMID:24940072

Behavior of poly(glycerol sebacate) plugs in chronic tympanic membrane perforations.

PubMed

Sundback, C A; McFadden, J; Hart, A; Kulig, K M; Wieland, A M; Pereira, M J N; Pomerantseva, I; Hartnick, C J; Masiakos, P T

2012-10-01

The tympanic membrane (TM), separating the external and middle ear, consists of fibrous connective tissue sandwiched between epithelial layers. To treat chronic ear infections, tympanostomy drainage tubes are placed in surgically created holes in TMs which can become chronic perforations upon extrusion. Perforations are repaired using a variety of techniques, but are limited by morbidity, unsatisfactory closure rates, or minimal regeneration of the connective tissue. A more effective, minimally-invasive therapy is necessary to enhance the perforation closure rate. Current research utilizing decellularized or alignate materials moderately enhance closure but the native TM architecture is not restored. Poly(glycerol sebacate) (PGS) is a biocompatible elastomer which supports cell migration and enzymatically degrades in contact with vascularized tissue. PGS spool-shaped plugs were manufactured using a novel process. Using minimally invasive procedures, these elastomeric plugs were inserted into chronic chinchilla TM perforations. As previously reported, effective perforation closure occurred as both flange surfaces were covered by confluent cell layers; >90% of perforations were closed at 6-week postimplantation. This unique in vivo environment has little vascularized tissue. Consequently, PGS degradation was minimal over 16-week implantation, hindering regeneration of the TM fibrous connective tissue. PGS degradation must be enhanced to promote complete TM regeneration. Copyright © 2012 Wiley Periodicals, Inc.

Development of 3D in Vitro Technology for Medical Applications

PubMed Central

Ou, Keng-Liang; Hosseinkhani, Hossein

2014-01-01

In the past few years, biomaterials technologies together with significant efforts on developing biology have revolutionized the process of engineered materials. Three dimensional (3D) in vitro technology aims to develop set of tools that are simple, inexpensive, portable and robust that could be commercialized and used in various fields of biomedical sciences such as drug discovery, diagnostic tools, and therapeutic approaches in regenerative medicine. The proliferation of cells in the 3D scaffold needs an oxygen and nutrition supply. 3D scaffold materials should provide such an environment for cells living in close proximity. 3D scaffolds that are able to regenerate or restore tissue and/or organs have begun to revolutionize medicine and biomedical science. Scaffolds have been used to support and promote the regeneration of tissues. Different processing techniques have been developed to design and fabricate three dimensional scaffolds for tissue engineering implants. Throughout the chapters we discuss in this review, we inform the reader about the potential applications of different 3D in vitro systems that can be applied for fabricating a wider range of novel biomaterials for use in tissue engineering. PMID:25299693

Injectable scaffolds: Preparation and application in dental and craniofacial regeneration

PubMed Central

Chang, Bei; Ahuja, Neelam; Ma, Chi; Liu, Xiaohua

2016-01-01

Injectable scaffolds are appealing for tissue regeneration because they offer many advantages over pre-formed scaffolds. This article provides a comprehensive review of the injectable scaffolds currently being investigated for dental and craniofacial tissue regeneration. First, we provide an overview of injectable scaffolding materials, including natural, synthetic, and composite biomaterials. Next, we discuss a variety of characteristic parameters and gelation mechanisms of the injectable scaffolds. The advanced injectable scaffolding systems developed in recent years are then illustrated. Furthermore, we summarize the applications of the injectable scaffolds for the regeneration of dental and craniofacial tissues that include pulp, dentin, periodontal ligament, temporomandibular joint, and alveolar bone. Finally, our perspectives on the injectable scaffolds for dental and craniofacial tissue regeneration are offered as signposts for the future advancement of this field. PMID:28649171

A bird's eye view on the use of electrospun nanofibrous scaffolds for bone tissue engineering: Current state-of-the-art, emerging directions and future trends.

PubMed

Rezvani, Zahra; Venugopal, Jayarama R; Urbanska, Aleksandra M; Mills, David K; Ramakrishna, Seeram; Mozafari, Masoud

2016-10-01

Tissue engineering aims to develop therapeutic products that utilize a combination of scaffolds with viable cell systems or responsive biomolecules derived from such cells, for the repair, restoration/regeneration of tissues. Here, the main goal is to enable the body to heal itself by the introduction of electrospun scaffolds, such that the body recognizes them as its own and in turn uses them to regenerate "neo-native" functional tissues. During the last decade, innovative nanofibrous scaffolds have attracted substantial interest in bone tissue engineering. The electrospinning process makes it possible to fabricate appropriate scaffolds for bone tissue engineering from different categories of nanobiomaterials having the ability of controlled delivery of drugs in the defective tissues. It is expected that with the progress in science and technology, better bone constructs will be proposed in the future. This review discusses the innovative approaches into electrospinning techniques for the fabrication of nanofibrous scaffolds for bone tissue engineering. Copyright © 2016 Elsevier Inc. All rights reserved.

In vivo characterization of Hyalonect, a novel biodegradable surgical mesh.

PubMed

Rhodes, Nicholas P; Hunt, John A; Longinotti, Cristina; Pavesio, Alessandra

2011-06-01

Musculoskeletal reconstructive surgery often requires removal of significant quantities of bone tissue, such as the periosteum, causing critical problems following surgery like friction between different tissues and adhesion of soft tissues to the underlying bone. We studied the long-term host response and closure of large bone defects for periosteal reconstruction using Hyalonect, a novel membrane comprising knitted fibers of esterified hyaluronan, (HYAFF11). For biological characterization, 162 rats were used in a defect model in which a section of the dorsal muscular fascia was removed, and the membrane behavior observed over 540 d using conventional histology, with sham operated rats as controls. In addition, Hyalonect was used to cover defects made in the humeri of 7 dogs, filled with a variety of conventional bone filling compounds, and the regeneration process observed after 6 wks using histology. Low levels of inflammation were observed in the dorsal muscle fascia defect model, with cellular colonization of the mesh by 30 d, vascularization by 120 days, matrix fiber organization by 270 d, and the appearance of connective tissue identical to the surrounding tissue between 365 and 540 d, without the formation of fibrotic tissue. In addition, Hyalonect was shown to allow the regeneration of bone within the humeral defects whilst preventing fibrotic tissue in-growth, and allowing regeneration of tissue which, by 6 wk, had begun to resemble natural periosteal tissue. Hyalonect is suitable for improving the outcome of the final phases of orthopedic and trauma reconstructive surgical procedures, especially in the reconstruction of periosteal tissue. Copyright © 2011. Published by Elsevier Inc.

Combined chemical and structural signals of biomaterials synergistically activate cell-cell communications for improving tissue regeneration.

PubMed

Xu, Yachen; Peng, Jinliang; Dong, Xin; Xu, Yuhong; Li, Haiyan; Chang, Jiang

2017-06-01

Biomaterials are only used as carriers of cells in the conventional tissue engineering. Considering the multi-cell environment and active cell-biomaterial interactions in tissue regeneration process, in this study, structural signals of aligned electrospun nanofibers and chemical signals of bioglass (BG) ionic products in cell culture medium are simultaneously applied to activate fibroblast-endothelial co-cultured cells in order to obtain an improved skin tissue engineering construct. Results demonstrate that the combined biomaterial signals synergistically activate fibroblast-endothelial co-culture skin tissue engineering constructs through promotion of paracrine effects and stimulation of gap junctional communication between cells, which results in enhanced vascularization and extracellular matrix protein synthesis in the constructs. Structural signals of aligned electrospun nanofibers play an important role in stimulating both of paracrine and gap junctional communication while chemical signals of BG ionic products mainly enhance paracrine effects. In vivo experiments reveal that the activated skin tissue engineering constructs significantly enhance wound healing as compared to control. This study indicates the advantages of synergistic effects between different bioactive signals of biomaterials can be taken to activate communication between different types of cells for obtaining tissue engineering constructs with improved functions. Tissue engineering can regenerate or replace tissue or organs through combining cells, biomaterials and growth factors. Normally, for repairing a specific tissue, only one type of cells, one kind of biomaterials, and specific growth factors are used to support cell growth. In this study, we proposed a novel tissue engineering approach by simply using co-cultured cells and combined biomaterial signals. Using a skin tissue engineering model, we successfully proved that the combined biomaterial signals such as surface nanostructures and bioactive ions could synergistically stimulate the cell-cell communication in co-culture system through paracrine effects and gap junction activation, and regulated expression of growth factors and extracellular matrix proteins, resulting in an activated tissue engineering constructs that significantly enhanced skin regeneration. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Local application of periodontal ligament stromal cells promotes soft tissue regeneration.

PubMed

Baik, H S; Park, J; Lee, K J; Chung, C

2014-09-01

To test the potential stimulatory effect of local application of periodontal ligament (PDL) stromal cells on soft tissue regeneration. Fluorescently labeled PDL cells outgrown from extracted human premolars or phosphate-buffered saline were locally injected to the cutaneous wounds created on mice. Soft tissue regeneration was evaluated for 14 days using photographs and histomorphometry. PDL cell engraftment was tracked with confocal microscopy. To detect the paracrine effect of the PDL cells on soft tissue regeneration, PDL cell-conditioned medium (CM) was evaluated for the concentration of secretory factors, transforming growth factor-beta 1 (TGFβ1). The effect of PDL CM on the proliferation and migration of dermal fibroblast and keratinocyte was tested using MTT assay and migration assay. The application of PDL cells significantly promoted soft tissue regeneration compared with the application of PBS. Self-replicating PDL cells were engrafted into the hair follicles of the host tissue. Dermal fibroblast proliferation and keratinocyte migration were significantly enhanced by the treatment with PDL CM. Physiologically significant amount of TGFβ1 was secreted from PDL cells into the CM. Local injection of PDL cells promoted soft tissue regeneration in part by the enhancement of fibroblast proliferation and keratinocyte migration through a paracrine mechanism. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Composite Scaffolds Containing Silk Fibroin, Gelatin, and Hydroxyapatite for Bone Tissue Regeneration and 3D Cell Culturing

PubMed Central

Moisenovich, M. M.; Arkhipova, A. Yu.; Orlova, A. A.; Drutskaya, M. S; Volkova, S. V.; Zacharov, S. E.; Agapov, I. I.; Kirpichnikov, M. P.

2014-01-01

Three-dimensional (3D) silk fibroin scaffolds were modified with one of the major bone tissue derivatives (nano-hydroxyapatite) and/or a collagen derivative (gelatin). Adhesion and proliferation of mouse embryonic fibroblasts (MEF) within the scaffold were increased after modification with either nano-hydroxyapatite or gelatin. However, a significant increase in MEF adhesion and proliferation was observed when both additives were introduced into the scaffold. Such modified composite scaffolds provide a new and better platform to study wound healing, bone and other tissue regeneration, as well as artificial organ bioengineering. This system can further be applied to establish experimental models to study cell-substrate interactions, cell migration and other complex processes, which may be difficult to address using the conventional two-dimensional culture systems. PMID:24772332

Animal models for periodontal regeneration and peri-implant responses.

PubMed

Kantarci, Alpdogan; Hasturk, Hatice; Van Dyke, Thomas E

2015-06-01

Translation of experimental data to the clinical setting requires the safety and efficacy of such data to be confirmed in animal systems before application in humans. In dental research, the animal species used is dependent largely on the research question or on the disease model. Periodontal disease and, by analogy, peri-implant disease, are complex infections that result in a tissue-degrading inflammatory response. It is impossible to explore the complex pathogenesis of periodontitis or peri-implantitis using only reductionist in-vitro methods. Both the disease process and healing of the periodontal and peri-implant tissues can be studied in animals. Regeneration (after periodontal surgery), in response to various biologic materials with potential for tissue engineering, is a continuous process involving various types of tissue, including epithelia, connective tissues and alveolar bone. The same principles apply to peri-implant healing. Given the complexity of the biology, animal models are necessary and serve as the standard for successful translation of regenerative materials and dental implants to the clinical setting. Smaller species of animal are more convenient for disease-associated research, whereas larger animals are more appropriate for studies that target tissue healing as the anatomy of larger animals more closely resembles human dento-alveolar architecture. This review focuses on the animal models available for the study of regeneration in periodontal research and implantology; the advantages and disadvantages of each animal model; the interpretation of data acquired; and future perspectives of animal research, with a discussion of possible nonanimal alternatives. Power calculations in such studies are crucial in order to use a sample size that is large enough to generate statistically useful data, whilst, at the same time, small enough to prevent the unnecessary use of animals. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Feather regeneration as a model for organogenesis

PubMed Central

Lin, Sung-Jan; Wideliz, Randall B; Yue, Zhicao; Li, Ang; Wu, Xiaoshan; Jiang, Ting-Xin; Wu, Ping; Chuong, Cheng-Ming

2013-01-01

In the process of organogenesis, different cell types form organized tissues and tissues are integrated into an organ. Most organs form in the developmental stage, but new organs can also form in physiological states or following injuries during adulthood. Feathers are a good model to study post-natal organogenesis because they regenerate episodically under physiological conditions and in response to injuries such as plucking. Epidermal stem cells in the collar can respond to activation signals. Dermal papilla located at the follicle base controls the regenerative process. Adhesion molecules (e.g., NCAM, tenascin), morphogens (e.g., Wnt3a, sprouty, FGF10), and differentiation markers (e.g., keratins) are expressed dynamically in initiation, growth and resting phases of the feather cycle. Epidermal cells are shaped into different feather morphologies based on the molecular micro-environment at the moment of morphogenesis. Chicken feather variants provide a rich resource for us to identify genetic determinants involved in feather regeneration and morphogenesis. An example of using genome-wide SNP analysis to identify alpha keratin 75 as the mutation in frizzled chickens is demonstrated. Due to its accessibility to experimental manipulation and observation, results of regeneration can be analyzed in a comprehensive way. The layout of time dimension along the distal (formed earlier) - proximal (formed later) feather axis makes the morphological analyses easier. Therefore feather regeneration can be a unique model for understanding organogenesis: from activation of stems cell under various physiological conditions to serving as the Rosetta stone for deciphering the language of morphogenesis. PMID:23294361

Cellularizing hydrogel-based scaffolds to repair bone tissue: How to create a physiologically relevant micro-environment?

PubMed Central

Maisani, Mathieu; Pezzoli, Daniele; Chassande, Olivier; Mantovani, Diego

2017-01-01

Tissue engineering is a promising alternative to autografts or allografts for the regeneration of large bone defects. Cell-free biomaterials with different degrees of sophistication can be used for several therapeutic indications, to stimulate bone repair by the host tissue. However, when osteoprogenitors are not available in the damaged tissue, exogenous cells with an osteoblast differentiation potential must be provided. These cells should have the capacity to colonize the defect and to participate in the building of new bone tissue. To achieve this goal, cells must survive, remain in the defect site, eventually proliferate, and differentiate into mature osteoblasts. A critical issue for these engrafted cells is to be fed by oxygen and nutrients: the transient absence of a vascular network upon implantation is a major challenge for cells to survive in the site of implantation, and different strategies can be followed to promote cell survival under poor oxygen and nutrient supply and to promote rapid vascularization of the defect area. These strategies involve the use of scaffolds designed to create the appropriate micro-environment for cells to survive, proliferate, and differentiate in vitro and in vivo. Hydrogels are an eclectic class of materials that can be easily cellularized and provide effective, minimally invasive approaches to fill bone defects and favor bone tissue regeneration. Furthermore, by playing on their composition and processing, it is possible to obtain biocompatible systems with adequate chemical, biological, and mechanical properties. However, only a good combination of scaffold and cells, possibly with the aid of incorporated growth factors, can lead to successful results in bone regeneration. This review presents the strategies used to design cellularized hydrogel-based systems for bone regeneration, identifying the key parameters of the many different micro-environments created within hydrogels. PMID:28634532

The TALE Class Homeobox Gene Smed-prep Defines the Anterior Compartment for Head Regeneration

PubMed Central

Felix, Daniel A.; Aboobaker, A. Aziz

2010-01-01

Planaria continue to blossom as a model system for understanding all aspects of regeneration. They provide an opportunity to understand how the replacement of missing tissues from preexisting adult tissue is orchestrated at the molecular level. When amputated along any plane, planaria are capable of regenerating all missing tissue and rescaling all structures to the new size of the animal. Recently, rapid progress has been made in understanding the developmental pathways that control planarian regeneration. In particular Wnt/beta-catenin signaling is central in promoting posterior fates and inhibiting anterior identity. Currently the mechanisms that actively promote anterior identity remain unknown. Here, Smed-prep, encoding a TALE class homeodomain, is described as the first gene necessary for correct anterior fate and patterning during planarian regeneration. Smed-prep is expressed at high levels in the anterior portion of whole animals, and Smed-prep(RNAi) leads to loss of the whole brain during anterior regeneration, but not during lateral regeneration or homeostasis in intact worms. Expression of markers of different anterior fated cells are greatly reduced or lost in Smed-prep(RNAi) animals. We find that the ectopic anterior structures induced by abrogation of Wnt signaling also require Smed-prep to form. We use double knockdown experiments with the S. mediterranea ortholog of nou-darake (that when knocked down induces ectopic brain formation) to show that Smed-prep defines an anterior fated compartment within which stem cells are permitted to assume brain fate, but is not required directly for this differentiation process. Smed-prep is the first gene clearly implicated as being necessary for promoting anterior fate and the first homeobox gene implicated in establishing positional identity during regeneration. Together our results suggest that Smed-prep is required in stem cell progeny as they form the anterior regenerative blastema and is required for specifying anterior cell fates and correct patterning. PMID:20422023

The TALE class homeobox gene Smed-prep defines the anterior compartment for head regeneration.

PubMed

Felix, Daniel A; Aboobaker, A Aziz

2010-04-22

Planaria continue to blossom as a model system for understanding all aspects of regeneration. They provide an opportunity to understand how the replacement of missing tissues from preexisting adult tissue is orchestrated at the molecular level. When amputated along any plane, planaria are capable of regenerating all missing tissue and rescaling all structures to the new size of the animal. Recently, rapid progress has been made in understanding the developmental pathways that control planarian regeneration. In particular Wnt/beta-catenin signaling is central in promoting posterior fates and inhibiting anterior identity. Currently the mechanisms that actively promote anterior identity remain unknown. Here, Smed-prep, encoding a TALE class homeodomain, is described as the first gene necessary for correct anterior fate and patterning during planarian regeneration. Smed-prep is expressed at high levels in the anterior portion of whole animals, and Smed-prep(RNAi) leads to loss of the whole brain during anterior regeneration, but not during lateral regeneration or homeostasis in intact worms. Expression of markers of different anterior fated cells are greatly reduced or lost in Smed-prep(RNAi) animals. We find that the ectopic anterior structures induced by abrogation of Wnt signaling also require Smed-prep to form. We use double knockdown experiments with the S. mediterranea ortholog of nou-darake (that when knocked down induces ectopic brain formation) to show that Smed-prep defines an anterior fated compartment within which stem cells are permitted to assume brain fate, but is not required directly for this differentiation process. Smed-prep is the first gene clearly implicated as being necessary for promoting anterior fate and the first homeobox gene implicated in establishing positional identity during regeneration. Together our results suggest that Smed-prep is required in stem cell progeny as they form the anterior regenerative blastema and is required for specifying anterior cell fates and correct patterning.

Strategies to Improve Regeneration of the Soft Palate Muscles After Cleft Palate Repair

PubMed Central

Carvajal Monroy, Paola L.; Grefte, Sander; Kuijpers-Jagtman, Anne Marie; Wagener, Frank A.D.T.G.

2012-01-01

Children with a cleft in the soft palate have difficulties with speech, swallowing, and sucking. These patients are unable to separate the nasal from the oral cavity leading to air loss during speech. Although surgical repair ameliorates soft palate function by joining the clefted muscles of the soft palate, optimal function is often not achieved. The regeneration of muscles in the soft palate after surgery is hampered because of (1) their low intrinsic regenerative capacity, (2) the muscle properties related to clefting, and (3) the development of fibrosis. Adjuvant strategies based on tissue engineering may improve the outcome after surgery by approaching these specific issues. Therefore, this review will discuss myogenesis in the noncleft and cleft palate, the characteristics of soft palate muscles, and the process of muscle regeneration. Finally, novel therapeutic strategies based on tissue engineering to improve soft palate function after surgical repair are presented. PMID:22697475

Strategies to improve regeneration of the soft palate muscles after cleft palate repair.

PubMed

Carvajal Monroy, Paola L; Grefte, Sander; Kuijpers-Jagtman, Anne Marie; Wagener, Frank A D T G; Von den Hoff, Johannes W

2012-12-01

Children with a cleft in the soft palate have difficulties with speech, swallowing, and sucking. These patients are unable to separate the nasal from the oral cavity leading to air loss during speech. Although surgical repair ameliorates soft palate function by joining the clefted muscles of the soft palate, optimal function is often not achieved. The regeneration of muscles in the soft palate after surgery is hampered because of (1) their low intrinsic regenerative capacity, (2) the muscle properties related to clefting, and (3) the development of fibrosis. Adjuvant strategies based on tissue engineering may improve the outcome after surgery by approaching these specific issues. Therefore, this review will discuss myogenesis in the noncleft and cleft palate, the characteristics of soft palate muscles, and the process of muscle regeneration. Finally, novel therapeutic strategies based on tissue engineering to improve soft palate function after surgical repair are presented.

Doubled haploid production in Flax (Linum usitatissimum L.).

PubMed

Obert, Bohus; Zácková, Zuzana; Samaj, Jozef; Pretová, Anna

2009-01-01

There is a requirement of haploid and double haploid material and homozygous lines for cell culture studies and breeding in flax. Anther culture is currently the most successful method producing doubled haploid lines in flax. Recently, ovary culture was also described as a good source of doubled haploids. In this review we focus on tissue and plants regeneration using anther culture, and cultivation of ovaries containing unfertilized ovules. The effect of genotype, physiological status of donor plants, donor material pre-treatment and cultivation conditions for flax anthers and ovaries is discussed here. The process of plant regeneration from anther and ovary derived calli is also in the focus of this review. Attention is paid to the ploidy level of regenerated tissue and to the use of molecular markers for determining of gametic origin of flax plants derived from anther and ovary cultures. Finally, some future prospects on the use of doubled haploids in flax biotechnology are outlined here.

Tissue engineering in periodontal tissue.

PubMed

Iwata, Takanori; Yamato, Masayuki; Ishikawa, Isao; Ando, Tomohiro; Okano, Teruo

2014-01-01

Periodontitis, a recognized disease worldwide, is bacterial infection-induced inflammation of the periodontal tissues that results in loss of alveolar bone. Once it occurs, damaged tissue cannot be restored to its original form, even if decontaminating treatments are performed. For more than half a century, studies have been conducted to investigate true periodontal regeneration. Periodontal regeneration is the complete reconstruction of the damaged attachment apparatus, which contains both hard tissue (alveolar bone and cementum) and soft tissue (periodontal ligament). Several treatments, including bone grafts, guided tissue regeneration with physical barriers for epithelial cells, and growth factors have been approved for clinical use; however, their indications and outcomes are limited. To overcome these limitations, the concept of "tissue engineering" was introduced. Combination treatment using cells, growth factors, and scaffolds, has been studied in experimental animal models, and some studies have been translated into clinical trials. In this review, we focus on recent progressive tissue engineering studies and discuss future perspectives on periodontal regeneration. Copyright © 2013 Wiley Periodicals, Inc.

PHRED-1 is a divergent neurexin-1 homolog that organizes muscle fibers and patterns organs during regeneration.

PubMed

Adler, Carolyn E; Sánchez Alvarado, Alejandro

2017-07-01

Regeneration of body parts requires the replacement of multiple cell types. To dissect this complex process, we utilized planarian flatworms that are capable of regenerating any tissue after amputation. An RNAi screen for genes involved in regeneration of the pharynx identified a novel gene, Pharynx regeneration defective-1 (PHRED-1) as essential for normal pharynx regeneration. PHRED-1 is a predicted transmembrane protein containing EGF, Laminin G, and WD40 domains, is expressed in muscle, and has predicted homologs restricted to other lophotrochozoan species. Knockdown of PHRED-1 causes abnormal regeneration of muscle fibers in both the pharynx and body wall muscle. In addition to defects in muscle regeneration, knockdown of PHRED-1 or the bHLH transcription factor MyoD also causes defects in muscle and intestinal regeneration. Together, our data demonstrate that muscle plays a key role in restoring the structural integrity of closely associated organs, and in planarians it may form a scaffold that facilitates normal intestinal branching. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Structural parameters of collagen nerve grafts influence peripheral nerve regeneration.

PubMed

Stang, Felix; Fansa, Hisham; Wolf, Gerald; Reppin, Michael; Keilhoff, Gerburg

2005-06-01

Large nerve defects require nerve grafts to allow regeneration. To avoid donor nerve problems the concept of tissue engineering was introduced into nerve surgery. However, non-neuronal grafts support axonal regeneration only to a certain extent. They lack viable Schwann cells which provide neurotrophic and neurotopic factors and guide the sprouting nerve. This experimental study used the rat sciatic nerve to bridge 2 cm nerve gaps with collagen (type I/III) tubes. The tubes were different in their physical structure (hollow versus inner collagen skeleton, different inner diameters). To improve regeneration Schwann cells were implanted. After 8 weeks the regeneration process was monitored clinically, histologically and morphometrically. Autologous nerve grafts and collagen tubes without Schwann cells served as control. In all parameters autologous nerve grafts showed best regeneration. Nerve regeneration in a noteworthy quality was also seen with hollow collagen tubes and tubes with reduced lumen, both filled with Schwann cells. The inner skeleton, however, impaired nerve regeneration independent of whether Schwann cells were added or not. This indicates that not only viable Schwann cells are an imperative prerequisite but also structural parameters determine peripheral nerve regeneration.

Ginsenoside Rg1 and platelet-rich fibrin enhance human breast adipose-derived stem cells function for soft tissue regeneration

PubMed Central

Li, Hong-Mian; Peng, Qi-Liu; Huang, Min-Hong; Li, De-Quan; Liang, Yi-Dan; Chi, Gang-Yi; Li, De-Hui; Yu, Bing-Chao; Huang, Ji-Rong

2016-01-01

Adipose-derived stem cells (ASCs) can be used to repair soft tissue defects, wounds, burns, and scars and to regenerate various damaged tissues. The cell differentiation capacity of ASCs is crucial for engineered adipose tissue regeneration in reconstructive and plastic surgery. We previously reported that ginsenoside Rg1 (G-Rg1 or Rg1) promotes proliferation and differentiation of ASCs in vitro and in vivio. Here we show that both G-Rg1 and platelet-rich fibrin (PRF) improve the proliferation, differentiation, and soft tissue regeneration capacity of human breast adipose-derived stem cells (HBASCs) on collagen type I sponge scaffolds in vitro and in vivo. Three months after transplantation, tissue wet weight, adipocyte number, intracellular lipid, microvessel density, and gene and protein expression of VEGF, HIF-1α, and PPARγ were higher in both G-Rg1- and PRF-treated HBASCs than in control grafts. More extensive new adipose tissue formation was evident after treatment with G-Rg1 or PRF. In summary, G-Rg1 and/or PRF co-administration improves the function of HBASCs for soft tissue regeneration engineering. PMID:27191987

Neurotrophic regulation of fibroblast dedifferentiation during limb skeletal regeneration in the axolotl (Ambystoma mexicanum).

PubMed

Satoh, Akira; Cummings, Gillian M C; Bryant, Susan V; Gardiner, David M

2010-01-15

The ability of animals to repair tissue damage is widespread and impressive. Among tissues, the repair and remodeling of bone occurs during growth and in response to injury; however, loss of bone above a threshold amount is not regenerated, resulting in a "critical-size defect" (CSD). The development of therapies to replace or regenerate a CSD is a major focus of research in regenerative medicine and tissue engineering. Adult urodeles (salamanders) are unique in their ability to regenerate complex tissues perfectly, yet like mammals do not regenerate a CSD. We report on an experimental model for the regeneration of a CSD in the axolotl (the Excisional Regeneration Model) that allows for the identification of signals to induce fibroblast dedifferentiation and skeletal regeneration. This regenerative response is mediated in part by BMP signaling, as is the case in mammals; however, a complete regenerative response requires the induction of a population of undifferentiated, regeneration-competent cells. These cells can be induced by signaling from limb amputation to generate blastema cells that can be grafted to the wound, as well as by signaling from a nerve and a wound epithelium to induce blastema cells from fibroblasts within the wound environment. Copyright 2009 Elsevier Inc. All rights reserved.

Uncovering the pathways underlying whole body regeneration in a chordate model, Botrylloides leachi using de novo transcriptome analysis.

PubMed

Zondag, Lisa E; Rutherford, Kim; Gemmell, Neil J; Wilson, Megan J

2016-02-16

Regenerative capacity differs greatly between animals. In vertebrates regenerative abilities are highly limited and tissue or organ specific. However the closest related chordate to the vertebrate clade, Botrylloides leachi, can undergo whole body regeneration (WBR). Therefore, research on WBR in B. leachi has focused on pathways known to be important for regeneration in vertebrates. To obtain a comprehensive vision of this unique process we have carried out the first de novo transcriptome sequencing for multiple stages of WBR occurring in B. leachi. The identified changes in gene expression during B. leachi WBR offer novel insights into this remarkable ability to regenerate. The transcriptome of B. leachi tissue undergoing WBR were analysed using differential gene expression, gene ontology and pathway analyses. We observed up-regulation in the expression of genes involved in wound healing and known developmental pathways including WNT, TGF-β and Notch, during the earliest stages of WBR. Later in WBR, the expression patterns in several pathways required for protein synthesis, biogenesis and the organisation of cellular components were up-regulated. While the genes expressed early on are characteristic of a necessary wound healing response to an otherwise lethal injury, the subsequent vast increase in protein synthesis conceivably sustains the reestablishment of the tissue complexity and body axis polarity within the regenerating zooid. We have, for the first time, provided a global overview of the genes and their corresponding pathways that are modulated during WBR in B. leachi.

Trophic Effects and Regenerative Potential of Mobilized Mesenchymal Stem Cells From Bone Marrow and Adipose Tissue as Alternative Cell Sources for Pulp/Dentin Regeneration.

PubMed

Murakami, Masashi; Hayashi, Yuki; Iohara, Koichiro; Osako, Yohei; Hirose, Yujiro; Nakashima, Misako

2015-01-01

Dental pulp stem cell (DPSC) subsets mobilized by granulocyte-colony-stimulating factor (G-CSF) are safe and efficacious for complete pulp regeneration. The supply of autologous pulp tissue, however, is very limited in the aged. Therefore, alternative sources of mesenchymal stem/progenitor cells (MSCs) are needed for the cell therapy. In this study, DPSCs, bone marrow (BM), and adipose tissue (AD)-derived stem cells of the same individual dog were isolated using G-CSF-induced mobilization (MDPSCs, MBMSCs, and MADSCs). The positive rates of CXCR4 and G-CSFR in MDPSCs were similar to MADSCs and were significantly higher than those in MBMSCs. Trophic effects of MDPSCs on angiogenesis, neurite extension, migration, and antiapoptosis were higher than those of MBMSCs and MADSCs. Pulp-like loose connective tissues were regenerated in all three MSC transplantations. Significantly higher volume of regenerated pulp and higher density of vascularization and innervation were observed in response to MDPSCs compared to MBMSC and MADSC transplantation. Collagenous matrix containing dentin sialophosphoprotein (DSPP)-positive odontoblast-like cells was the highest in MBMSCs and significantly higher in MADSCs compared to MDPSCs. MBMSCs and MADSCs, therefore, have potential for pulp regeneration, although the volume of regenerated pulp tissue, angiogenesis, and reinnervation, were less. Thus, in conclusion, an alternative cell source for dental pulp/dentin regeneration are stem cells from BM and AD tissue.

Gene expression profiles of fin regeneration in loach (Paramisgurnus dabryanu).

PubMed

Li, Li; He, Jingya; Wang, Linlin; Chen, Weihua; Chang, Zhongjie

2017-11-01

Teleost fins can regenerate accurate position-matched structure and function after amputation. However, we still lack systematic transcriptional profiling and methodologies to understand the molecular basis of fin regeneration. After histological analysis, we established a suppression subtraction hybridization library containing 418 distinct sequences expressed differentially during the process of blastema formation and differentiation in caudal fin regeneration. Genome ontology and comparative analysis of differential distribution of our data and the reference zebrafish genome showed notable subcategories, including multi-organism processes, response to stimuli, extracellular matrix, antioxidant activity, and cell junction function. KEGG pathway analysis allowed the effective identification of relevant genes in those pathways involved in tissue morphogenesis and regeneration, including tight junction, cell adhesion molecules, mTOR and Jak-STAT signaling pathway. From relevant function subcategories and signaling pathways, 78 clones were examined for further Southern-blot hybridization. Then, 17 genes were chosen and characterized using semi-quantitative PCR. Then 4 candidate genes were identified, including F11r, Mmp9, Agr2 and one without a match to any database. After real-time quantitative PCR, the results showed obvious expression changes in different periods of caudal fin regeneration. We can assume that the 4 candidates, likely valuable genes associated with fin regeneration, deserve additional attention. Thus, our study demonstrated how to investigate the transcript profiles with an emphasis on bioinformatics intervention and how to identify potential genes related to fin regeneration processes. The results also provide a foundation or knowledge for further research into genes and molecular mechanisms of fin regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

Current Methods for Skeletal Muscle Tissue Repair and Regeneration

PubMed Central

Liu, Juan; Saul, Dominik; Böker, Kai Oliver; Ernst, Jennifer; Lehman, Wolfgang

2018-01-01

Skeletal muscle has the capacity of regeneration after injury. However, for large volumes of muscle loss, this regeneration needs interventional support. Consequently, muscle injury provides an ongoing reconstructive and regenerative challenge in clinical work. To promote muscle repair and regeneration, different strategies have been developed within the last century and especially during the last few decades, including surgical techniques, physical therapy, biomaterials, and muscular tissue engineering as well as cell therapy. Still, there is a great need to develop new methods and materials, which promote skeletal muscle repair and functional regeneration. In this review, we give a comprehensive overview over the epidemiology of muscle tissue loss, highlight current strategies in clinical treatment, and discuss novel methods for muscle regeneration and challenges for their future clinical translation. PMID:29850487

Instructive Biologic Scaffold for Functional Tissue Regeneration Following Trauma to the Extremities

DTIC Science & Technology

2016-10-01

Award Number: W81XWH-12-2-0128 TITLE: Instructive Biologic Scaffold for Functional Tissue Regeneration Following Trauma to the Extremities...SUBTITLE Instructive Biologic Scaffold for Functional Tissue Regeneration Following Trauma to the Extremities 5a. CONTRACT NUMBER 5b. GRANT NUMBER...identification of cell phenotype, extracellular 5 matrix characterization, and histomorphometric analysis. The main endpoint of this study was to

Live imaging reveals the progenitors and cell dynamics of limb regeneration

PubMed Central

Alwes, Frederike; Enjolras, Camille; Averof, Michalis

2016-01-01

Regeneration is a complex and dynamic process, mobilizing diverse cell types and remodelling tissues over long time periods. Tracking cell fate and behaviour during regeneration in active adult animals is especially challenging. Here, we establish continuous live imaging of leg regeneration at single-cell resolution in the crustacean Parhyale hawaiensis. By live recordings encompassing the first 4-5 days after amputation, we capture the cellular events that contribute to wound closure and morphogenesis of regenerating legs with unprecedented resolution and temporal detail. Using these recordings we are able to track cell lineages, to generate fate maps of the blastema and to identify the progenitors of regenerated epidermis. We find that there are no specialized stem cells for the epidermis. Most epidermal cells in the distal part of the leg stump proliferate, acquire new positional values and contribute to new segments in the regenerating leg. DOI: http://dx.doi.org/10.7554/eLife.19766.001 PMID:27776632

Comparative analysis of ear-hole closure identifies epimorphic regeneration as a discrete trait in mammals

PubMed Central

Gawriluk, Thomas R.; Simkin, Jennifer; Thompson, Katherine L.; Biswas, Shishir K.; Clare-Salzler, Zak; Kimani, John M.; Kiama, Stephen G.; Smith, Jeramiah J.; Ezenwa, Vanessa O.; Seifert, Ashley W.

2016-01-01

Why mammals have poor regenerative ability has remained a long-standing question in biology. In regenerating vertebrates, injury can induce a process known as epimorphic regeneration to replace damaged structures. Using a 4-mm ear punch assay across multiple mammalian species, here we show that several Acomys spp. (spiny mice) and Oryctolagus cuniculus completely regenerate tissue, whereas other rodents including MRL/MpJ ‘healer' mice heal similar injuries by scarring. We demonstrate ear-hole closure is independent of ear size, and closure rate can be modelled with a cubic function. Cellular and genetic analyses reveal that injury induces blastema formation in Acomys cahirinus. Despite cell cycle re-entry in Mus musculus and A. cahirinus, efficient cell cycle progression and proliferation only occurs in spiny mice. Together, our data unite blastema-mediated regeneration in spiny mice with regeneration in other vertebrates such as salamanders, newts and zebrafish, where all healthy adults regenerate in response to injury. PMID:27109826

High throughput measurement of metabolism in planarians reveals activation of glycolysis during regeneration

PubMed Central

Osuma, Edie A.; Riggs, Daniel W.; Gibb, Andrew A.

2018-01-01

Abstract Planarians are outstanding models for studying mechanisms of regeneration; however, there are few methods to measure changes in their metabolism. Examining metabolism in planarians is important because the regenerative process is dependent on numerous integrated metabolic pathways, which provide the energy required for tissue repair as well as the ability to synthesize the cellular building blocks needed to form new tissue. Therefore, we standardized an extracellular flux analysis method to measure mitochondrial and glycolytic activity in live planarians during normal growth as well as during regeneration. Small, uninjured planarians showed higher rates of oxygen consumption compared with large planarians, with no difference in glycolytic activity; however, glycolysis increased during planarian regeneration. Exposure of planarians to koningic acid, a specific inhibitor of glyceraldehyde‐3‐phosphate dehydrogenase, completely abolished extracellular acidification with little effect on oxygen consumption, which suggests that the majority of glucose catabolized in planarians is fated for aerobic glycolysis. These studies describe a useful method for measuring respiration and glycolysis in planarians and provide data implicating changes in glucose metabolism in the regenerative response. PMID:29721328

Neuronal regeneration in the newt: a model to study the partly reconstruction of the neural tissue in real and simulated weightles sness

NASA Astrophysics Data System (ADS)

Anton, H.; Grigoryan, E.; Mitashov, V.

The micro -"g" effect on nervous tissue regeneration in newts has been investigated by our group for many years. It has been performed in real and in simulated microgravity with a clinostat. During limb regeneration the motor - and sensory nerves regrow perfectly within the newly formed limb. Like in `1g' conditions they are responsible for the initiation of blastema formation and continuity of g owth andr differentiation. Except for a general acceleration of growth and differentiation processes no differences became visible. Tail regeneration, which is perfectly regulated in newts during their whole life, includes the restoration of the spinal cord and dorsal root ganglia. They follow or initiate an accelerated growth. Up to the present the cellular derivation of the sensory neurones within the regenerate has not yet been clarified. But growth acceleration comprises the whole nervous system. That means a totally new formation of the sensory connection from the periphery to the whole spinal cord. Regeneration must be initiated by the outgrowth of nerve fibres into the wound area. This may be performed by the remaining cut sensory fibres of the last stump segment and should be followed by the differentiation of undifferentiated cells of neural crest origin nearby the amputation area. Such cells are present in the form of meningeal cells which are the origin of mantle and Schwann cells too. Corresponding to the well proved growth acceleration of lens, retina, connective tissue, muscle and skin, the real and simulated microgravity affects the nervous system in the same manner. Tissues and organs of adult organisms have no chance to remain unaffected by the microgravity effect. We try to find the trigger which initiates the accelerated proliferation of the stem cells of sensory neurons, mantle and sheath cells under micro-"g" conditions.

Strategies for Controlled Delivery of Growth Factors and Cells for Bone Regeneration

PubMed Central

Vo, Tiffany N.; Kasper, F. Kurtis; Mikos, Antonios G.

2012-01-01

The controlled delivery of growth factors and cells within biomaterial carriers can enhance and accelerate functional bone formation. The carrier system can be designed with preprogrammed release kinetics to deliver bioactive molecules in a localized, spatiotemporal manner most similar to the natural wound healing process. The carrier can also act as an extracellular matrix-mimicking substrate for promoting osteoprogenitor cellular infiltration and proliferation for integrative tissue repair. This review discusses the role of various regenerative factors involved in bone healing and their appropriate combinations with different delivery systems for augmenting bone regeneration. The general requirements of protein, cell and gene therapy are described, with elaboration on how the selection of materials, configurations and processing affects growth factor and cell delivery and regenerative efficacy in both in vitro and in vivo applications for bone tissue engineering. PMID:22342771

Dedifferentiated Schwann Cell Precursors Secreting Paracrine Factors Are Required for Regeneration of the Mammalian Digit Tip.

PubMed

Johnston, Adam P W; Yuzwa, Scott A; Carr, Matthew J; Mahmud, Neemat; Storer, Mekayla A; Krause, Matthew P; Jones, Karen; Paul, Smitha; Kaplan, David R; Miller, Freda D

2016-10-06

Adult mammals have lost multi-tissue regenerative capacity, except for the distal digit, which is able to regenerate via mechanisms that remain largely unknown. Here, we show that, after adult mouse distal digit removal, nerve-associated Schwann cell precursors (SCPs) dedifferentiate and secrete growth factors that promote expansion of the blastema and digit regeneration. When SCPs were dysregulated or ablated, mesenchymal precursor proliferation in the blastema was decreased and nail and bone regeneration were impaired. Transplantation of exogenous SCPs rescued these regeneration defects. We found that SCPs secrete factors that promote self-renewal of mesenchymal precursors, and we used transcriptomic and proteomic analysis to define candidate factors. Two of these, oncostatin M (OSM) and platelet-derived growth factor AA (PDGF-AA), are made by SCPs in the regenerating digit and rescued the deficits in regeneration caused by loss of SCPs. As all peripheral tissues contain nerves, these results could have broad implications for mammalian tissue repair and regeneration. Copyright © 2016 Elsevier Inc. All rights reserved.

Optimally designed collagen/polycaprolactone biocomposites supplemented with controlled release of HA/TCP/rhBMP-2 and HA/TCP/PRP for hard tissue regeneration.

PubMed

Kim, WonJin; Jang, Chul Ho; Kim, GeunHyung

2017-09-01

Collagen has been widely used as a very promising material to regenerate various tissues. It is a chief component of the extracellular matrix, and encourages various biological effects conducive to tissue regeneration. However, poor mechanical stability, low processability, and high level of water absorption can lead to impaired control of growth factor release and have impeded the use of collagen as a functional biomedical scaffold. Here, to overcome the shortcomings of collagen scaffolds, we have additively manufactured collagen/polycaprolactone (PCL) biocomposites supplemented with a bioceramic (hydroxyapatite (HA)/β-tricalcium-phosphate (TCP)) and two growth factors (recombinant human bone morphogenetic protein-2 [rhBMP-2] and platelet-rich plasma [PRP]). Various weight fractions of PCL in the collagen/PCL composites were manipulated to select optimal growth factor release and highly active cellular responses. After the optimal concentration of PCL in the collagen/PCL scaffold was determined, biocomposites supplemented with bioceramic/growth-factors were fabricated. Continuously released growth factors were assumed to increase the in vitro cellular activities of the osteoblast-like cells (MG63) cultured on the biocomposites. In vitro cellular responses, including osteogenic activities, were examined, and results showed that compared to the HA/TCP/rhBMP-2 supplemented scaffold the HA/TCP/PRP biocomposites provide significantly high cellular activities (cell proliferation: >1.3-fold) and mineralization (calcium deposition: >1.4-fold, osteocalcin: >2.6-fold) sufficient for regenerating bone tissue. Copyright © 2017. Published by Elsevier B.V.

Honeybee product therapeutic as stem cells homing for ovary failure.

PubMed

Safitri, Erma; Widiyatno, Thomas V; Prasetyo, R Heru

2016-11-01

Complexity of the method of isolation, cultivation in vitro and the expensive cost of transplantation process of stem cells, it would require an innovation to homing and differentiation of stem cells and increase folliculogenesis. The stem cells homing was achieved through the provision of food or beverages derived from natural materials like honeybee product. Through honeybee product, there will be homing of stem cells and accompany with the sources from the body itself will take place in regeneration of the ovary. Female rats model of degenerative ovary was obtained through food fasting but still have drinking water for 5 days. It caused malnutrition and damage of the ovarian tissue. The administration of 50% honeybee product (T1) was performed for 10 consecutive days, while the positive control group (T0+) was fasted and not given honeybee product and the negative control (T0-) not fasted and without honeybee product. Observations were taken for homing of stem cells, raised of folliculogenesis, differentiation of stem cells, and regeneration of the ovarian tissue using routine H&E staining. Homing of stem cells shown the vascular endothelial growth factor and granulocyte colony-stimulating factor expression; enhancement of folliculogenesis was indicated by an increase of follicle dee Graaf count; enhancement of differentiation of stem cells was indicated by growth differentiation factor-9 expression; and regeneration of ovarian tissue indicated by intact ovarian tissue with growing follicles. Honeybee product can be induced endogenous stem cells in regeneration of ovary failure due to malnutrition.

Piezoelectric materials as stimulatory biomedical materials and scaffolds for bone repair.

PubMed

Tandon, Biranche; Blaker, Jonny J; Cartmell, Sarah H

2018-04-16

The process of bone repair and regeneration requires multiple physiological cues including biochemical, electrical and mechanical - that act together to ensure functional recovery. Myriad materials have been explored as bioactive scaffolds to deliver these cues locally to the damage site, amongst these piezoelectric materials have demonstrated significant potential for tissue engineering and regeneration, especially for bone repair. Piezoelectric materials have been widely explored for power generation and harvesting, structural health monitoring, and use in biomedical devices. They have the ability to deform with physiological movements and consequently deliver electrical stimulation to cells or damaged tissue without the need of an external power source. Bone itself is piezoelectric and the charges/potentials it generates in response to mechanical activity are capable of enhancing bone growth. Piezoelectric materials are capable of stimulating the physiological electrical microenvironment, and can play a vital role to stimulate regeneration and repair. This review gives an overview of the association of piezoelectric effect with bone repair, and focuses on state-of-the-art piezoelectric materials (polymers, ceramics and their composites), the fabrication routes to produce piezoelectric scaffolds, and their application in bone repair. Important characteristics of these materials from the perspective of bone tissue engineering are highlighted. Promising upcoming strategies and new piezoelectric materials for this application are presented. Electrical stimulation/electrical microenvironment are known effect the process of bone regeneration by altering the cellular response and are crucial in maintaining tissue functionality. Piezoelectric materials, owing to their capability of generating charges/potentials in response to mechanical deformations, have displayed great potential for fabricating smart stimulatory scaffolds for bone tissue engineering. The growing interest of the scientific community and compelling results of the published research articles has been the motivation of this review article. This article summarizes the significant progress in the field with a focus on the fabrication aspects of piezoelectric materials. The review of both material and cellular aspects on this topic ensures that this paper appeals to both material scientists and tissue engineers. Copyright © 2018. Published by Elsevier Ltd.

Enzyme-crosslinked gene-activated matrix for the induction of mesenchymal stem cells in osteochondral tissue regeneration.

PubMed

Lee, Yi-Hsuan; Wu, Hsi-Chin; Yeh, Chia-Wei; Kuan, Chen-Hsiang; Liao, Han-Tsung; Hsu, Horng-Chaung; Tsai, Jui-Che; Sun, Jui-Sheng; Wang, Tzu-Wei

2017-11-01

The development of osteochondral tissue engineering is an important issue for the treatment of traumatic injury or aging associated joint disease. However, the different compositions and mechanical properties of cartilage and subchondral bone show the complexity of this tissue interface, making it challenging for the design and fabrication of osteochondral graft substitute. In this study, a bilayer scaffold is developed to promote the regeneration of osteochondral tissue within a single integrated construct. It has the capacity to serve as a gene delivery platform to promote transfection of human mesenchymal stem cells (hMSCs) and the functional osteochondral tissues formation. For the subchondral bone layer, the bone matrix with organic (type I collagen, Col) and inorganic (hydroxyapatite, Hap) composite scaffold has been developed through mineralization of hydroxyapatite nanocrystals oriented growth on collagen fibrils. We also prepare multi-shell nanoparticles in different layers with a calcium phosphate core and DNA/calcium phosphate shells conjugated with polyethyleneimine to act as non-viral vectors for delivery of plasmid DNA encoding BMP2 and TGF-β3, respectively. Microbial transglutaminase is used as a cross-linking agent to crosslink the bilayer scaffold. The ability of this scaffold to act as a gene-activated matrix is demonstrated with successful transfection efficiency. The results show that the sustained release of plasmids from gene-activated matrix can promote prolonged transgene expression and stimulate hMSCs differentiation into osteogenic and chondrogenic lineages by spatial and temporal control within the bilayer composite scaffold. This improved delivery method may enhance the functionalized composite graft to accelerate healing process for osteochondral tissue regeneration. In this study, a gene-activated matrix (GAM) to promote the growth of both cartilage and subchondral bone within a single integrated construct is developed. It has the capacity to promote transfection of human mesenchymal stem cells (hMSCs) and the functional osteochondral tissues formation. The results show that the sustained release of plasmids including TGF-beta and BMP-2 from GAM could promote prolonged transgene expression and stimulate hMSCs differentiation into the osteogenic and chondrogenic lineages by spatial control manner. This improved delivery method should enhance the functionalized composite graft to accelerate healing process in vitro and in vivo for osteochondral tissue regeneration. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Overlapping Mechanisms of Peripheral Nerve Regeneration and Angiogenesis Following Sciatic Nerve Transection

PubMed Central

Wang, Hongkui; Zhu, Hui; Guo, Qi; Qian, Tianmei; Zhang, Ping; Li, Shiying; Xue, Chengbin; Gu, Xiaosong

2017-01-01

Peripheral nervous system owns the ability of self-regeneration, mainly in its regenerative microenvironment including vascular network reconstruction. More recently, more attentions have been given to the close relationship between tissue regeneration and angiogenesis. To explore the overlap of molecular mechanisms and key regulation molecules between peripheral nerve regeneration and angiogenesis post peripheral nerve injury, integrative and bioinformatic analysis was carried out for microarray data of proximal stumps after sciatic nerve transection in SD rats. Nerve regeneration and angiogenesis were activated at 1 day immediately after sciatic nerve transection simultaneously. The more obvious changes of transcription regulators and canonical pathways suggested a phase transition between 1 and 4 days of both nerve regeneration and angiogenesis after sciatic nerve transection. Furthermore, 16 differentially expressed genes participated in significant biological processes of both nerve regeneration and angiogenesis, a few of which were validated by qPCR and immunofluorescent staining. It was demonstrated that STAT3, EPHB3, and Cdc42 co-expressed in Schwann cells and vascular endothelial cells to play a key role in regulation of nerve regeneration and angiogenesis simultaneously response to sciatic nerve transection. We provide a framework for understanding biological processes and precise molecular correlations between peripheral nerve regeneration and angiogenesis after peripheral nerve transection. Our work serves as an experimental basis and a valuable resource to further understand molecular mechanisms that define nerve injury-induced micro-environmental variation for achieving desired peripheral nerve regeneration. PMID:29085283

Overlapping Mechanisms of Peripheral Nerve Regeneration and Angiogenesis Following Sciatic Nerve Transection.

PubMed

Wang, Hongkui; Zhu, Hui; Guo, Qi; Qian, Tianmei; Zhang, Ping; Li, Shiying; Xue, Chengbin; Gu, Xiaosong

2017-01-01

Peripheral nervous system owns the ability of self-regeneration, mainly in its regenerative microenvironment including vascular network reconstruction. More recently, more attentions have been given to the close relationship between tissue regeneration and angiogenesis. To explore the overlap of molecular mechanisms and key regulation molecules between peripheral nerve regeneration and angiogenesis post peripheral nerve injury, integrative and bioinformatic analysis was carried out for microarray data of proximal stumps after sciatic nerve transection in SD rats. Nerve regeneration and angiogenesis were activated at 1 day immediately after sciatic nerve transection simultaneously. The more obvious changes of transcription regulators and canonical pathways suggested a phase transition between 1 and 4 days of both nerve regeneration and angiogenesis after sciatic nerve transection. Furthermore, 16 differentially expressed genes participated in significant biological processes of both nerve regeneration and angiogenesis, a few of which were validated by qPCR and immunofluorescent staining. It was demonstrated that STAT3, EPHB3, and Cdc42 co-expressed in Schwann cells and vascular endothelial cells to play a key role in regulation of nerve regeneration and angiogenesis simultaneously response to sciatic nerve transection. We provide a framework for understanding biological processes and precise molecular correlations between peripheral nerve regeneration and angiogenesis after peripheral nerve transection. Our work serves as an experimental basis and a valuable resource to further understand molecular mechanisms that define nerve injury-induced micro-environmental variation for achieving desired peripheral nerve regeneration.

Monitoring of injury induced brain regeneration of the adult zebrafish by using optical coherence tomography

NASA Astrophysics Data System (ADS)

Yuan, Zhen; Zhang, Jian

2018-02-01

The adult zebrafish has pronounced regenerative capacity of the brain, which makes it an ideal model organism of vertebrate biology for the investigation of recovery of central nervous system injuries. The aim of this study was to employ spectral-domain optical coherence tomography (SD-OCT) system for long-term in vivo monitoring of tissue regeneration using an adult zebrafish model of brain injury. Based on a 1325 nm light source and two high-speed galvo mirrors, the SD-OCT system can offer a large field of view of the three-dimensional (3D) brain structures with high imaging resolution (12 μm axial and 13 μm lateral) at video rate. In vivo experiments based on this system were conducted to monitor the regeneration process of zebrafish brain after injury during a period of 43 days. To monitor and detect the process of tissue regeneration, we performed 3D in vivo imaging in a zebrafish model of adult brain injury during a period of 43 days. The coronal and sagittal views of the injured zebrafish brain at each time point (0 days, 10 days, 20 days and 43 days postlesion) were presented to show the changes of the brain lesion in detail. In addition, the 3D SD-OCT images for an injured zebrafish brain were also reconstructed at days 0 and days 43 post-lesion. We found that SD-OCT is able to effectively and noninvasively monitor the regeneration of the adult zebrafish brain after injury in real time with high 3D spatial resolution and good penetration depth. Our findings also suggested that the adult zebrafish has the extraordinary capability of brain regeneration and is able to repair itself after brain injury.

Effect of Escherichia coli-produced recombinant human bone morphogenetic protein 2 on the regeneration of canine segmental ulnar defects.

PubMed

Harada, Yasuji; Itoi, Takamasa; Wakitani, Shigeyuki; Irie, Hiroyuki; Sakamoto, Michiko; Zhao, Dongwei; Nezu, Yoshinori; Yogo, Takuya; Hara, Yasushi; Tagawa, Masahiro

2012-07-01

Because bone morphogenetic protein 2 gene transfected Escherichia coli (E-BMP-2) produce recombinant human BMP-2 (rhBMP-2) more efficiently than mammalian cells (Chinese hamster ovary [CHO]-BMP-2), they may be a more cost-effective source of rhBMP-2 for clinical use. However, use of E-BMP-2 for regenerating long bones in large animals has not been reported. In the current study, we evaluated the healing efficacy of E-BMP-2 in a canine model. We created 2.5-cm critical-size segmental ulnar defects in test animals, then implanted E-BMP-2 and 700 mg of artificial bone (beta-tricalcium phosphate; β-TCP) into the wounds. We examined the differential effects of 5 E-BMP-2 treatments (0, 35, 140, 560, and 2240 μg) across 5 experimental groups (control, BMP35, BMP140, BMP560, and BMP2240). Radiography and computed tomography were used to observe the regeneration process. The groups in which higher doses of E-BMP-2 were administered (BMP560 and BMP2240) displayed more pronounced bone regeneration; the regenerated tissues connected to the host bone, and the cross-sectional areas of the regenerated bone were larger than those of the originals. The groups in which lower doses of E-BMP-2 were administered (BMP35 and BMP140) experienced relatively less bone regeneration; furthermore, the regenerated tissues failed to connect to the host bone. In these groups, the cross-sectional areas of the regenerated bone were equal to or smaller than those of the originals. No regeneration was observed in the control group. These findings suggest that, like CHO-BMP-2, E-BMP-2 can be used for the regeneration of large defects in long bones and that its clinical use might decrease the cost of bone regeneration treatments.

Differential expression of GAP-43 and neurofilament during peripheral nerve regeneration through bio-artificial conduits.

PubMed

Carriel, Víctor; Garzón, Ingrid; Campos, Antonio; Cornelissen, Maria; Alaminos, Miguel

2017-02-01

Nerve conduits are promising alternatives for repairing nerve gaps; they provide a close microenvironment that supports nerve regeneration. In this sense, histological analysis of axonal growth is a determinant to achieve successful nerve regeneration. To evaluate this process, the most-used immunohistochemical markers are neurofilament (NF), β-III tubulin and, infrequently, GAP-43. However, GAP-43 expression in long-term nerve regeneration models is still poorly understood. In this study we analysed GAP-43 expression and its correlation with NF and S-100, using three tissue-engineering approaches with different regeneration profiles. A 10 mm gap was created in the sciatic nerve of 12 rats and repaired using collagen conduits or collagen conduits filled with fibrin-agarose hydrogels or with hydrogels containing autologous adipose-derived mesenchymal stem cells (ADMSCs). After 12 weeks the conduits were harvested for histological analysis. Our results confirm the long-term expression of GAP-43 in all groups. The expression of GAP-43 and NF was significantly higher in the group with ADMSCs. Interestingly, GAP-43 was observed in immature, newly formed axons and NF in thicker and mature axons. These proteins were not co-expressed, demonstrating their differential expression in newly formed nerve fascicles. Our descriptive and quantitative histological analysis of GAP-43 and NFL allowed us to determine, with high accuracy, the heterogenic population of axons at different stages of maturation in three tissue-engineering approaches. Finally, to perform a complete assessment of axonal regeneration, the quantitative immunohistochemical evaluation of both GAP-43 and NF could be a useful quality control in tissue engineering. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

Periodontal regeneration around natural teeth.

PubMed

Garrett, S

1996-11-01

1. Evidence is conclusive (Table 2) that periodontal regeneration in humans is possible following the use of bone grafts, guided tissue regeneration procedures, both without and in combination with bone grafts, and root demineralization procedures. 2. Clinically guided tissue regeneration procedures have demonstrated significant positive clinical change beyond that achieved with debridement alone in treating mandibular and maxillary (buccal only) Class II furcations. Similar data exist for intraosseous defects. Evidence suggests that the use of bone grafts or GTR procedures produce equal clinical benefit in treating intraosseous defects. Further research is necessary to evaluate GTR procedures compared to, or combined with, bone grafts in treating intraosseous defects. 3. Although there are some data suggesting hopeful results in Class II furcations, the clinical advantage of procedures combining present regenerative techniques remains to be demonstrated. Additional randomized controlled trials with sufficient power are needed to demonstrate the potential usefulness of these techniques. 4. Outcomes following regenerative attempts remain somewhat variable with differences in results between studies and individual subjects. Some of this variability is likely patient related in terms of compliance with plaque control and maintenance procedures, as well as personal habits; e.g., smoking. Variations in the defects selected for study may also affect predictability of outcomes along with other factors. 5. There is evidence to suggest that present regenerative techniques lead to significant amounts of regeneration at localized sites on specific teeth. However, if complete regeneration is to become a reality, additional stimuli to enhance the regenerative process are likely needed. Perhaps this will be accomplished in the future, with combined procedures that include appropriate polypeptide growth factors or tissue factors to provide additional stimulus.

Acellular bi-layer silk fibroin scaffolds support tissue regeneration in a rabbit model of onlay urethroplasty.

PubMed

Chung, Yeun Goo; Tu, Duong; Franck, Debra; Gil, Eun Seok; Algarrahi, Khalid; Adam, Rosalyn M; Kaplan, David L; Estrada, Carlos R; Mauney, Joshua R

2014-01-01

Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a rabbit model of urethra repair. A bi-layer silk fibroin matrix was fabricated by a solvent-casting/salt leaching process in combination with silk fibroin film casting to generate porous foams buttressed by homogeneous silk fibroin films. Ventral onlay urethroplasty was performed with silk fibroin grafts (Group 1, N = 4) (Width × Length, 1 × 2 cm(2)) in adult male rabbits for 3 m of implantation. Parallel control groups consisted of animals receiving small intestinal submucosa (SIS) implants (Group 2, N = 4) or urethrotomy alone (Group 3, N = 3). Animals in all groups exhibited 100% survival prior to scheduled euthanasia and achieved voluntary voiding following 7 d of initial catheterization. Retrograde urethrography of each implant group at 3 m post-op revealed wide urethral calibers and preservation of organ continuity similar to pre-operative and urethrotomy controls with no evidence of contrast extravasation, strictures, fistulas, or stone formation. Histological (hematoxylin and eosin and Masson's trichrome), immunohistochemical, and histomorphometric analyses demonstrated that both silk fibroin and SIS scaffolds promoted similar extents of smooth muscle and epithelial tissue regeneration throughout the original defect sites with prominent contractile protein (α-smooth muscle actin and SM22α) and cytokeratin expression, respectively. De novo innervation and vascularization were also evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Following 3 m post-op, minimal acute inflammatory reactions were elicited by silk fibroin scaffolds characterized by the presence of eosinophil granulocytes while SIS matrices promoted chronic inflammatory responses indicated by mobilization of mononuclear cell infiltrates. The results of this study demonstrate that bi-layer silk fibroin scaffolds represent promising biomaterials for onlay urethroplasty, capable of promoting similar degrees of tissue regeneration in comparison to conventional SIS scaffolds, but with reduced immunogenicity.

Acellular Bi-Layer Silk Fibroin Scaffolds Support Tissue Regeneration in a Rabbit Model of Onlay Urethroplasty

PubMed Central

Franck, Debra; Gil, Eun Seok; Algarrahi, Khalid; Adam, Rosalyn M.; Kaplan, David L.; Estrada Jr., Carlos R.; Mauney, Joshua R.

2014-01-01

Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a rabbit model of urethra repair. A bi-layer silk fibroin matrix was fabricated by a solvent-casting/salt leaching process in combination with silk fibroin film casting to generate porous foams buttressed by homogeneous silk fibroin films. Ventral onlay urethroplasty was performed with silk fibroin grafts (Group 1, N = 4) (Width×Length, 1×2 cm2) in adult male rabbits for 3 m of implantation. Parallel control groups consisted of animals receiving small intestinal submucosa (SIS) implants (Group 2, N = 4) or urethrotomy alone (Group 3, N = 3). Animals in all groups exhibited 100% survival prior to scheduled euthanasia and achieved voluntary voiding following 7 d of initial catheterization. Retrograde urethrography of each implant group at 3 m post-op revealed wide urethral calibers and preservation of organ continuity similar to pre-operative and urethrotomy controls with no evidence of contrast extravasation, strictures, fistulas, or stone formation. Histological (hematoxylin and eosin and Masson's trichrome), immunohistochemical, and histomorphometric analyses demonstrated that both silk fibroin and SIS scaffolds promoted similar extents of smooth muscle and epithelial tissue regeneration throughout the original defect sites with prominent contractile protein (α-smooth muscle actin and SM22α) and cytokeratin expression, respectively. De novo innervation and vascularization were also evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Following 3 m post-op, minimal acute inflammatory reactions were elicited by silk fibroin scaffolds characterized by the presence of eosinophil granulocytes while SIS matrices promoted chronic inflammatory responses indicated by mobilization of mononuclear cell infiltrates. The results of this study demonstrate that bi-layer silk fibroin scaffolds represent promising biomaterials for onlay urethroplasty, capable of promoting similar degrees of tissue regeneration in comparison to conventional SIS scaffolds, but with reduced immunogenicity. PMID:24632740

Regenerative Medicine for Periodontal and Peri-implant Diseases

PubMed Central

Larsson, L.; Decker, A.M.; Nibali, L.; Pilipchuk, S.P.; Berglundh, T.; Giannobile, W.V.

2015-01-01

The balance between bone resorption and bone formation is vital for maintenance and regeneration of alveolar bone and supporting structures around teeth and dental implants. Tissue regeneration in the oral cavity is regulated by multiple cell types, signaling mechanisms, and matrix interactions. A goal for periodontal tissue engineering/regenerative medicine is to restore oral soft and hard tissues through cell, scaffold, and/or signaling approaches to functional and aesthetic oral tissues. Bony defects in the oral cavity can vary significantly, ranging from smaller intrabony lesions resulting from periodontal or peri-implant diseases to large osseous defects that extend through the jaws as a result of trauma, tumor resection, or congenital defects. The disparity in size and location of these alveolar defects is compounded further by patient-specific and environmental factors that contribute to the challenges in periodontal regeneration, peri-implant tissue regeneration, and alveolar ridge reconstruction. Efforts have been made over the last few decades to produce reliable and predictable methods to stimulate bone regeneration in alveolar bone defects. Tissue engineering/regenerative medicine provide new avenues to enhance tissue regeneration by introducing bioactive models or constructing patient-specific substitutes. This review presents an overview of therapies (e.g., protein, gene, and cell based) and biomaterials (e.g., resorbable, nonresorbable, and 3-dimensionally printed) used for alveolar bone engineering around teeth and implants and for implant site development, with emphasis on most recent findings and future directions. PMID:26608580

Body Management: Mesenchymal Stem Cells Control the Internal Regenerator

PubMed Central

Hariri, Robert

2015-01-01

Summary It has been assumed that adult tissues cannot regenerate themselves. With the current understanding that every adult tissue has its own intrinsic progenitor or stem cell, it is now clear that almost all tissues have regenerative potential partially related to their innate turnover dynamics. Moreover, it appears that a separate class of local cells originating as perivascular cells appears to provide regulatory oversight for localized tissue regeneration. The management of this regeneration oversight has a profound influence on the use of specific cells for cell therapies as a health care delivery tool set. The multipotent mesenchymal stem cell (MSC), now renamed the medicinal signaling cell, predominantly arises from pericytes released from broken and inflamed blood vessels and appears to function as both an immunomodulatory and a regeneration mediator. MSCs are being tested for their management capabilities to produce therapeutic outcomes in more than 480 clinical trials for a wide range of clinical conditions. Local MSCs function by managing the body’s primary repair and regeneration activities. Supplemental MSCs can be provided from either endogenous or exogenous sources of either allogeneic or autologous origin. This MSC-based therapy has the potential to change how health care is delivered. These medicinal cells are capable of sensing their surroundings. Also, by using its complex signaling circuitry, these cells organize site-specific regenerative responses as if these therapeutic cells were well-programmed modern computers. Given these facts, it appears that we are entering a new age of cellular medicine. Significance This report is a perspective from an active scientist and an active entrepreneur and commercial leader. It is neither a comprehensive review nor a narrowly focused treatise. The broad themes and the analogy to the working component of a computer and that of a cell are meant to draw several important scientific principles and health care themes together into the thesis that regenerative medicine is a constant throughout life and its management is the next frontier of health care. Mesenchymal stem cells are used as the central connection in the broad theme, not as multipotent progenitors but rather as an important control element in the natural local regeneration process. PMID:26019227

THE POTENTIAL ROLE OF ENDOGENOUS STEM CELLS IN REGENERATION OF THE INNER EAR

PubMed Central

Martinez-Monedero, Rodrigo; Oshima, Kazuo; Heller, Stefan; Edge, Albert S.B.

2007-01-01

Stem cells in various mammalian tissues retain the capacity to renew themselves and may be able to restore damaged tissue. Their existence has been proven by genetic tracer studies that demonstrate their differentiation into multiple tissue types and by their ability to self-renew through proliferation. Stem cells from the adult nervous system proliferate to form clonal floating colonies called spheres in vitro, and recent studies have demonstrated sphere formation by cells in the cochlea in addition to the vestibular system and the auditory ganglia, indicating that these tissues contain cells with stem cell properties. The presence of stem cells in the inner ear raises the hope of regeneration of mammalian inner ear cells but is difficult to correlate with the lack spontaneous regeneration seen in the inner ear after tissue damage. Loss of stem cells postnatally in the cochlea may correlate with the loss of regenerative capacity and may limit our ability to stimulate regeneration. Retention of sphere forming capacity in adult vestibular tissues suggests that the limited capacity for repair may be attributed to the continued presence of progenitor cells. Future strategies for regeneration must consider the distribution of endogenous stem cells in the inner ear and whether cells with the capacity for regeneration are retained. PMID:17321086

Concise Review: Translating Regenerative Biology into Clinically Relevant Therapies: Are We on the Right Path?

PubMed Central

2017-01-01

Abstract Despite approaches in regenerative medicine using stem cells, bio‐engineered scaffolds, and targeted drug delivery to enhance human tissue repair, clinicians remain unable to regenerate large‐scale, multi‐tissue defects in situ. The study of regenerative biology using mammalian models of complex tissue regeneration offers an opportunity to discover key factors that stimulate a regenerative rather than fibrotic response to injury. For example, although primates and rodents can regenerate their distal digit tips, they heal more proximal amputations with scar tissue. Rabbits and African spiny mice re‐grow tissue to fill large musculoskeletal defects through their ear pinna, while other mammals fail to regenerate identical defects and instead heal ear holes through fibrotic repair. This Review explores the utility of these comparative healing models using the spiny mouse ear pinna and the mouse digit tip to consider how mechanistic insight into reparative regeneration might serve to advance regenerative medicine. Specifically, we consider how inflammation and immunity, extracellular matrix composition, and controlled cell proliferation intersect to establish a pro‐regenerative microenvironment in response to injuries. Understanding how some mammals naturally regenerate complex tissue can provide a blueprint for how we might manipulate the injury microenvironment to enhance regenerative abilities in humans. Stem Cells Translational Medicine 2018;7:220–231 PMID:29271610

Myocardial regeneration potential of adipose tissue-derived stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bai, Xiaowen, E-mail: baixw01@yahoo.com; Alt, Eckhard, E-mail: ealt@mdanderson.org

Research highlights: {yields} Various tissue resident stem cells are receiving tremendous attention from basic scientists and clinicians and hold great promise for myocardial regeneration. {yields} For practical reasons, human adipose tissue-derived stem cells are attractive stem cells for future clinical application in repairing damaged myocardium. {yields} This review summarizes the characteristics of cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential and the, underlying mechanisms, and safety issues. -- Abstract: Various tissue resident stem cells are receiving attention from basic scientists and clinicians as they hold promise for myocardial regeneration. For practical reasons, adipose tissue-derivedmore » stem cells (ASCs) are attractive cells for clinical application in repairing damaged myocardium based on the following advantages: abundant adipose tissue in most patients and easy accessibility with minimally invasive lipoaspiration procedure. Several recent studies have demonstrated that both cultured and freshly isolated ASCs could improve cardiac function in animal model of myocardial infarction. The mechanisms underlying the beneficial effect of ASCs on myocardial regeneration are not fully understood. Growing evidence indicates that transplantation of ASCs improve cardiac function via the differentiation into cardiomyocytes and vascular cells, and through paracrine pathways. Paracrine factors secreted by injected ASCs enhance angiogenesis, reduce cell apoptosis rates, and promote neuron sprouts in damaged myocardium. In addition, Injection of ASCs increases electrical stability of the injured heart. Furthermore, there are no reported cases of arrhythmia or tumorigenesis in any studies regarding myocardial regeneration with ASCs. This review summarizes the characteristics of both cultured and freshly isolated stem cells obtained from adipose tissue, their myocardial regeneration potential, and the underlying mechanisms for beneficial effect on cardiac function, and safety issues.« less

The Hippo pathway: key interaction and catalytic domains in organ growth control, stem cell self-renewal and tissue regeneration.

PubMed

Cherrett, Claire; Furutani-Seiki, Makoto; Bagby, Stefan

2012-01-01

The Hippo pathway is a conserved pathway that interconnects with several other pathways to regulate organ growth, tissue homoeostasis and regeneration, and stem cell self-renewal. This pathway is unique in its capacity to orchestrate multiple processes, from sensing to execution, necessary for organ expansion. Activation of the Hippo pathway core kinase cassette leads to cytoplasmic sequestration of the nuclear effectors YAP (Yes-associated protein) and TAZ (transcriptional coactivator with PDZ-binding motif), consequently disabling their transcriptional co-activation function. Components upstream of the core kinase cassette have not been well understood, especially in vertebrates, but are gradually being elucidated and include cell polarity and cell adhesion proteins.

Poly (lactic acid)-based biomaterials for orthopaedic regenerative engineering.

PubMed

Narayanan, Ganesh; Vernekar, Varadraj N; Kuyinu, Emmanuel L; Laurencin, Cato T

2016-12-15

Regenerative engineering converges tissue engineering, advanced materials science, stem cell science, and developmental biology to regenerate complex tissues such as whole limbs. Regenerative engineering scaffolds provide mechanical support and nanoscale control over architecture, topography, and biochemical cues to influence cellular outcome. In this regard, poly (lactic acid) (PLA)-based biomaterials may be considered as a gold standard for many orthopaedic regenerative engineering applications because of their versatility in fabrication, biodegradability, and compatibility with biomolecules and cells. Here we discuss recent developments in PLA-based biomaterials with respect to processability and current applications in the clinical and research settings for bone, ligament, meniscus, and cartilage regeneration. Copyright © 2016 Elsevier B.V. All rights reserved.

Chemical activation of Wnt/β-catenin signalling inhibits innervation and causes skeletal tissue malformations during axolotl limb regeneration.

PubMed

Wischin, Sabina; Castañeda-Patlán, Cristina; Robles-Flores, Martha; Chimal-Monroy, Jesús

2017-04-01

Limb regeneration involves several interrelated physiological processes in which a particular signalling pathway may play a variety of functions. Blocking the function of Wnt/β-catenin signalling during limb regeneration inhibits regeneration in axolotls (Ambystoma mexicanum). Limb development shares many features with limb regeneration, and Wnt/β-catenin activation has different effects depending on the developmental stage. The aim of this study was to evaluate whether Wnt/β-catenin signalling activation during axolotl limb regeneration has different effects when activated at different stages of regeneration. To evaluate this hypothesis, we treated amputated axolotls with a Wnt agonist chemical at different stages of limb regeneration. The results showed that limb regeneration was inhibited when the treatment began before blastema formation. Under these conditions, blastema formation was hindered, possibly due to the lack of innervation. On the other hand, when axolotls were treated after blastema formation and immediately before the onset of morphogenesis, we observed structural disorganization in skeletal formation. In conclusion, we found that limb regeneration was differentially affected depending on the stage at which the Wnt signalling pathway was activated. Copyright © 2017 Elsevier B.V. All rights reserved.

Branch regeneration induced by sever damage in the brown alga Dictyota dichotoma (dictyotales, phaeophyceae).

PubMed

Tanaka, Atsuko; Hoshino, Yoichiro; Nagasato, Chikako; Motomura, Taizo

2017-05-01

Tissue wounds are mainly caused by herbivory, which is a serious threat for macro-algae, and brown algae are known to regenerate branches or buds in response to wounding. In the present paper, we describe a branch regeneration system, induced by sever damage, in the brown alga Dictyota dichotoma. Segmentations of juvenile thalli induced branch regenerations unless explants possessed apical cells. Apical excisions in distinct positions elucidated that disruption of an apical cell or disconnection of tissue with an apical cell triggered the branch regeneration. Furthermore, spatial positions of regenerated branches seemed to be regulated by the apical region, which was assumed to generate inhibitory effects for lateral branch regeneration. Mechanical incision, which disrupted tissue continuity with the apical region, induced branch regeneration preferentially below the incision. Although we were unable to identify the candidate inhibitory substance, our results suggested that the apical region may have an inhibitory effect on lateral branch regeneration. Additionally, observations of branch regeneration showed that all epidermal cells in D. dichotoma possess the ability to differentiate into apical cells, directly. This may be the first report of algal transdifferentiation during the wound-stress response.

Investigation into the cellular origins of posterior regeneration in the annelid Capitella teleta

PubMed Central

de Jong, Danielle M.

2017-01-01

Abstract Many animals can regenerate, although there is great diversity in regenerative capabilities. A major question in regenerative biology is determining the cellular source of newly formed tissue. The polychaete annelid, Capitella teleta, can regenerate posterior segments following transverse amputation. However, the source, behavior and molecular characteristics of the cells that form new tissue during regeneration are largely unknown. Using an indirect cell tracking method involving 5′‐ethynyl‐2′‐deoxyuridine (EdU) incorporation, we show that cell migration occurs during C. teleta posterior regeneration. Expression of the multipotency/germ line marker CapI‐vasa led us to hypothesize that stem cells originate from a multipotent progenitor cell (MPC) cluster, migrate through the coelomic cavity, and contribute to regeneration of tissue. We show that the capacity for posterior regeneration and segment formation is greater with than without the MPC cluster. Finally, we propose a working model of posterior regeneration in C. teleta. This work is the first in C. teleta that addresses the potential source of cells contributing to posterior regeneration, and may provide clues as to why some animals are highly successful regenerators. PMID:29721327

Generating favorable growth factor and protease release profiles to enable extracellular matrix accumulation within an in vitro tissue engineering environment.

PubMed

Zhang, Xiaoqing; Battiston, Kyle G; Labow, Rosalind S; Simmons, Craig A; Santerre, J Paul

2017-05-01

Tissue engineering (particularly for the case of load-bearing cardiovascular and connective tissues) requires the ability to promote the production and accumulation of extracellular matrix (ECM) components (e.g., collagen, glycosaminoglycan and elastin). Although different approaches have been attempted in order to enhance ECM accumulation in tissue engineered constructs, studies of underlying signalling mechanisms that influence ECM deposition and degradation during tissue remodelling and regeneration in multi-cellular culture systems have been limited. The current study investigated vascular smooth muscle cell (VSMC)-monocyte co-culture systems using different VSMC:monocyte ratios, within a degradable polyurethane scaffold, to assess their influence on ECM generation and degradation processes, and to elucidate relevant signalling molecules involved in this in vitro vascular tissue engineering system. It was found that a desired release profile of growth factors (e.g. insulin growth factor-1 (IGF-1)) and hydrolytic proteases (e.g. matrix-metalloproteinases 2, 9, 13 and 14 (MMP2, MMP9, MMP13 and MMP14)), could be achieved in co-culture systems, yielding an accumulation of ECM (specifically for 2:1 and 4:1 VSMC:monocyte culture systems). This study has significant implications for the tissue engineering field (including vascular tissue engineering), not only because it identified important cytokines and proteases that control ECM accumulation/degradation within synthetic tissue engineering scaffolds, but also because the established culture systems could be applied to improve the development of different types of tissue constructs. Sufficient extracellular matrix accumulation within cardiovascular and connective tissue engineered constructs is a prerequisite for their appropriate function in vivo. This study established co-culture systems with tissue specific cells (vascular smooth muscle cells (VSMCs)) and defined ratios of immune cells (monocytes) to investigate extracellular matrix (ECM) generation and degradation processes, revealing important mechanisms underlying ECM turnover during vascular tissue regeneration/remodelling. A specific growth factor (IGF-1), as well as hydrolytic proteases (e.g. MMP2, MMP9, MMP13 and MMP14), were identified as playing important roles in these processes. ECM accumulation was found to be dependent on achieving a desired release profile of these ECM-promoting and ECM-degrading factors within the multi-cellular microenvironment. The findings enhance our understanding of ECM deposition and degradation during in vitro tissue engineering and would be applicable to the repair or regeneration of a variety of tissues. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effects of the incorporation of ε-aminocaproic acid/chitosan particles to fibrin on cementoblast differentiation and cementum regeneration.

PubMed

Park, Chan Ho; Oh, Joung-Hwan; Jung, Hong-Moon; Choi, Yoonnyoung; Rahman, Saeed Ur; Kim, Sungtae; Kim, Tae-Il; Shin, Hong-In; Lee, Yun-Sil; Yu, Frank H; Baek, Jeong-Hwa; Ryoo, Hyun-Mo; Woo, Kyung Mi

2017-10-01

Cementum formation on the exposed tooth-root surface is a critical process in periodontal regeneration. Although various therapeutic approaches have been developed, regeneration of integrated and functional periodontal complexes is still wanting. Here, we found that the OCCM30 cementoblasts cultured on fibrin matrix express substantial levels of matrix proteinases, leading to the degradation of fibrin and the apoptosis of OCCM30 cells, which was reversed upon treatment with a proteinase inhibitor, ε-aminocaproic acid (ACA). Based on these findings, ACA-releasing chitosan particles (ACP) were fabricated and ACP-incorporated fibrin (fibrin-ACP) promoted the differentiation of cementoblasts in vitro, as confirmed by bio-mineralization and expressions of molecules associated with mineralization. In a periodontal defect model of beagle dogs, fibrin-ACP resulted in substantial cementum formation on the exposed root dentin in vivo, compared to fibrin-only and enamel matrix derivative (EMD) which is used clinically for periodontal regeneration. Remarkably, the fibrin-ACP developed structural integrations of the cementum-periodontal ligament-bone complex by the Sharpey's fiber insertion. In addition, fibrin-ACP promoted alveolar bone regeneration through increased bone volume of tooth roof-of-furcation defects and root coverage. Therefore, fibrin-ACP can promote cementogenesis and osteogenesis by controlling biodegradability of fibrin, implicating the feasibility of its therapeutic use to improve periodontal regeneration. Cementum, the mineralized layer on root dentin surfaces, functions to anchor fibrous connective tissues on tooth-root surfaces with the collagenous Sharpey's fibers integration, of which are essential for periodontal functioning restoration in the complex. Through the cementum-responsible fiber insertions on tooth-root surfaces, PDLs transmit various mechanical responses to periodontal complexes against masticatory/occlusal stimulations to support teeth. In this study, periodontal tissue regeneration was enhanced by use of modified fibrin biomaterial which significantly promoted cementogenesis within the periodontal complex with structural integration by collagenous Sharpey's fiber insertions in vivo by controlling fibrin degradation and consequent cementoblast apoptosis. Furthermore, the modified fibrin could improve repair and regeneration of tooth roof-of-furcation defects, which has spatial curvatures and geometrical difficulties and hardly regenerates periodontal tissues. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Pulp regeneration in a full-length human tooth root using a hierarchical nanofibrous microsphere system.

PubMed

Li, Xiangwei; Ma, Chi; Xie, Xiaohua; Sun, Hongchen; Liu, Xiaohua

2016-04-15

While pulp regeneration using tissue engineering strategy has been explored for over a decade, successful regeneration of pulp tissues in a full-length human root with a one-end seal that truly simulates clinical endodontic treatment has not been achieved. To address this challenge, we designed and synthesized a unique hierarchical growth factor-loaded nanofibrous microsphere scaffolding system. In this system, vascular endothelial growth factor (VEGF) binds with heparin and is encapsulated in heparin-conjugated gelatin nanospheres, which are further immobilized in the nanofibers of an injectable poly(l-lactic acid) (PLLA) microsphere. This hierarchical microsphere system not only protects the VEGF from denaturation and degradation, but also provides excellent control of its sustained release. In addition, the nanofibrous PLLA microsphere integrates the extracellular matrix-mimicking architecture with a highly porous injectable form, efficiently accommodating dental pulp stem cells (DPSCs) and supporting their proliferation and pulp tissue formation. Our in vivo study showed the successful regeneration of pulp-like tissues that fulfilled the entire apical and middle thirds and reached the coronal third of the full-length root canal. In addition, a large number of blood vessels were regenerated throughout the canal. For the first time, our work demonstrates the success of pulp tissue regeneration in a full-length root canal, making it a significant step toward regenerative endodontics. The regeneration of pulp tissues in a full-length tooth root canal has been one of the greatest challenges in the field of regenerative endodontics, and one of the biggest barriers for its clinical application. In this study, we developed a unique approach to tackle this challenge, and for the first time, we successfully regenerated living pulp tissues in a full-length root canal, making it a significant step toward regenerative endodontics. This study will make positive scientific impact and interest the broad and multidisciplinary readership in the dental biomaterials and craniofacial tissue engineering community. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

TORC1 is required to balance cell proliferation and cell death in planarians

PubMed Central

Tu, Kimberly C.; Pearson, Bret J.; Alvarado, Alejandro Sánchez

2012-01-01

Multicellular organisms are equipped with cellular mechanisms that enable them to replace differentiated cells lost to normal physiological turnover, injury, and for some such as planarians, even amputation. This process of tissue homeostasis is generally mediated by adult stem cells (ASCs), tissue-specific stem cells responsible for maintaining anatomical form and function. To do so, ASCs must modulate the balance between cell proliferation, i.e. in response to nutrients, and that of cell death, i.e. in response to starvation or injury. But how these two antagonistic processes are coordinated remains unclear. Here, we explore the role of the core components of the TOR pathway during planarian tissue homeostasis and regeneration and identified an essential function for TORC1 in these two processes. RNAi-mediated silencing of TOR in intact animals resulted in a significant increase in cell death, whereas stem cell proliferation and stem cell maintenance were unaffected. Amputated animals failed to increase stem cell proliferation after wounding and displayed defects in tissue remodeling. Together, our findings suggest two distinct roles for TORC1 in planarians. TORC1 is required to modulate the balance between cell proliferation and cell death during normal cell turnover and in response to nutrients. In addition, it is required to initiate appropriate stem cell proliferation during regeneration and for proper tissue remodeling to occur to maintain scale and proportion. PMID:22445864

Articular cartilage tissue engineering with plasma-rich in growth factors and stem cells with nano scaffolds

NASA Astrophysics Data System (ADS)

Montaser, Laila M.; Abbassy, Hadeer A.; Fawzy, Sherin M.

2016-09-01

The ability to heal soft tissue injuries and regenerate cartilage is the Holy Grail of musculoskeletal medicine. Articular cartilage repair and regeneration is considered to be largely intractable due to the poor regenerative properties of this tissue. Due to their low self-repair ability, cartilage defects that result from joint injury, aging, or osteoarthritis, are the most often irreversible and are a major cause of joint pain and chronic disability. However, current methods do not perfectly restore hyaline cartilage and may lead to the apparition of fibro- or continue hypertrophic cartilage. The lack of efficient modalities of treatment has prompted research into tissue engineering combining stem cells, scaffold materials and environmental factors. The field of articular cartilage tissue engineering, which aims to repair, regenerate, and/or improve injured or diseased cartilage functionality, has evoked intense interest and holds great potential for improving cartilage therapy. Plasma-rich in growth factors (PRGF) and/or stem cells may be effective for tissue repair as well as cartilage regenerative processes. There is a great promise to advance current cartilage therapies toward achieving a consistently successful approach for addressing cartilage afflictions. Tissue engineering may be the best way to reach this objective via the use of stem cells, novel biologically inspired scaffolds and, emerging nanotechnology. In this paper, current and emergent approach in the field of cartilage tissue engineering is presented for specific application. In the next years, the development of new strategies using stem cells, in scaffolds, with supplementation of culture medium could improve the quality of new formed cartilage.

MicroRNA profiling of antler stem cells in potentiated and dormant states and their potential roles in antler regeneration.

PubMed

Ba, Hengxing; Wang, Datao; Li, Chunyi

2016-04-01

MicroRNAs (miRNAs) can effectively regulate gene expression at the post-transcriptional level and play a critical role in tissue growth, development and regeneration. Our previous studies showed that antler regeneration is a stem cell-based process and antler stem cells reside in the periosteum of a pedicle, the permanent bony protuberance, from which antler regeneration takes place. Antlers are the only mammalian organ that can fully regenerate and hence provide a unique opportunity to identify miRNAs that are involved in organ regeneration. In the present study, we used next generation sequencing technology sequenced miRNAs of the stem cells derived from either the potentiated or the dormant pedicle periosteum. A population of both conserved and 20 deer-specific miRNAs was identified. These conserved miRNAs were derived from 453 homologous hairpin precursors across 88 animal species, and were further grouped into 167 miRNA families. Among them, the miR-296 is embryonic stem cell-specific. The potentiation process resulted in the significant regulation (>±2 Fold, q value <0.05) of conserved miRNAs; 8 miRNA transcripts were down- and 6 up-regulated. Several GO biology processes and the Wnt, MAPK and TGF-beta signaling pathways were found to be up-regulated as part of antlerogenic stem cell potentiation process. This research has identified miRNAs that are associated either with the dormant or the potentiated antler stem cells and identified some target miRNAs for further research into their role played in mammalian organ regeneration.

Bioactive Glasses: From Parent 45S5 Composition to Scaffold-Assisted Tissue-Healing Therapies

PubMed Central

Fiume, Elisa; Barberi, Jacopo; Verné, Enrica

2018-01-01

Nowadays, bioactive glasses (BGs) are mainly used to improve and support the healing process of osseous defects deriving from traumatic events, tumor removal, congenital pathologies, implant revisions, or infections. In the past, several approaches have been proposed in the replacement of extensive bone defects, each one with its own advantages and drawbacks. As a result, the need for synthetic bone grafts is still a remarkable clinical challenge since more than 1 million bone-graft surgical operations are annually performed worldwide. Moreover, recent studies show the effectiveness of BGs in the regeneration of soft tissues, too. Often, surgical criteria do not match the engineering ones and, thus, a compromise is required for getting closer to an ideal outcome in terms of good regeneration, mechanical support, and biocompatibility in contact with living tissues. The aim of the present review is providing a general overview of BGs, with particular reference to their use in clinics over the last decades and the latest synthesis/processing methods. Recent advances in the use of BGs in tissue engineering are outlined, where the use of porous scaffolds is gaining growing importance thanks to the new possibilities given by technological progress extended to both manufacturing processes and functionalization techniques. PMID:29547544

Activated macrophages create lineage-specific microenvironments for pancreatic acinar- and β-cell regeneration in mice.

PubMed

Criscimanna, Angela; Coudriet, Gina M; Gittes, George K; Piganelli, Jon D; Esni, Farzad

2014-11-01

Although the cells that contribute to pancreatic regeneration have been widely studied, little is known about the mediators of this process. During tissue regeneration, infiltrating macrophages debride the site of injury and coordinate the repair response. We investigated the role of macrophages in pancreatic regeneration in mice. We used a saporin-conjugated antibody against CD11b to reduce the number of macrophages in mice following diphtheria toxin receptor-mediated cell ablation of pancreatic cells, and evaluated the effects on pancreatic regeneration. We analyzed expression patterns of infiltrating macrophages after cell-specific injury or from the pancreas of nonobese diabetic mice. We developed an in vitro culture system to study the ability of macrophages to induce cell-specific regeneration. Depletion of macrophages impaired pancreatic regeneration. Macrophage polarization, as assessed by expression of tumor necrosis factor-α, interleukin 6, interleukin 10, and CD206, depended on the type of injury. The signals provided by polarized macrophages promoted lineage-specific generation of acinar or endocrine cells. Macrophage from nonobese diabetic mice failed to provide signals necessary for β-cell generation. Macrophages produce cell type-specific signals required for pancreatic regeneration in mice. Additional study of these processes and signals might lead to new approaches for treating type 1 diabetes or pancreatitis. Copyright © 2014 AGA Institute. Published by Elsevier Inc. All rights reserved.

Design and fabrication of porous biodegradable scaffolds: a strategy for tissue engineering.

PubMed

Raeisdasteh Hokmabad, Vahideh; Davaran, Soodabeh; Ramazani, Ali; Salehi, Roya

2017-11-01

Current strategies of tissue engineering are focused on the reconstruction and regeneration of damaged or deformed tissues by grafting of cells with scaffolds and biomolecules. Recently, much interest is given to scaffolds which are based on mimic the extracellular matrix that have induced the formation of new tissues. To return functionality of the organ, the presence of a scaffold is essential as a matrix for cell colonization, migration, growth, differentiation and extracellular matrix deposition, until the tissues are totally restored or regenerated. A wide variety of approaches has been developed either in scaffold materials and production procedures or cell sources and cultivation techniques to regenerate the tissues/organs in tissue engineering applications. This study has been conducted to present an overview of the different scaffold fabrication techniques such as solvent casting and particulate leaching, electrospinning, emulsion freeze-drying, thermally induced phase separation, melt molding and rapid prototyping with their properties, limitations, theoretical principles and their prospective in tailoring appropriate micro-nanostructures for tissue regeneration applications. This review also includes discussion on recent works done in the field of tissue engineering.

A shell regeneration assay to identify biomineralization candidate genes in mytilid mussels.

PubMed

Hüning, Anne K; Lange, Skadi M; Ramesh, Kirti; Jacob, Dorrit E; Jackson, Daniel J; Panknin, Ulrike; Gutowska, Magdalena A; Philipp, Eva E R; Rosenstiel, Philip; Lucassen, Magnus; Melzner, Frank

2016-06-01

Biomineralization processes in bivalve molluscs are still poorly understood. Here we provide an analysis of specifically expressed sequences from a mantle transcriptome of the blue mussel, Mytilus edulis. We then developed a novel, integrative shell injury assay to test, whether biomineralization candidate genes highly expressed in marginal and pallial mantle could be induced in central mantle tissue underlying the damaged shell areas. This experimental approach makes it possible to identify gene products that control the chemical micro-environment during calcification as well as organic matrix components. This is unlike existing methodological approaches that work retroactively to characterize calcification relevant molecules and are just able to examine organic matrix components that are present in completed shells. In our assay an orthogonal array of nine 1mm holes was drilled into the left valve, and mussels were suspended in net cages for 20, 29 and 36days to regenerate. Structural observations using stereo-microscopy, SEM and Raman spectroscopy revealed organic sheet synthesis (day 20) as the first step of shell-repair followed by the deposition of calcite crystals (days 20 and 29) and aragonite tablets (day 36). The regeneration period was characterized by time-dependent shifts in gene expression in left central mantle tissue underlying the injured shell, (i) increased expression of two tyrosinase isoforms (TYR3: 29-fold and TYR6: 5-fold) at day 20 with a decline thereafter, (ii) an increase in expression of a gene encoding a nacrein-like protein (max. 100-fold) on day 29. The expression of an acidic Asp-Ser-rich protein was enhanced during the entire regeneration process. This proof-of-principle study demonstrates that genes that are specifically expressed in pallial and marginal mantle tissue can be induced (4 out of 10 genes) in central mantle following experimental injury of the overlying shell. Our findings suggest that regeneration assays can be used systematically to better characterize gene products that are essential for distinct phases of the shell formation process, particularly those that are not incorporated into the organic shell matrix. Copyright © 2016 Elsevier B.V. All rights reserved.

Reformation of tissue balls from tentacle explants of coral Goniopora lobata: self-organization process and response to environmental stresses.

PubMed

Lu, Qiongxuan; Liu, Tao; Tang, Xianming; Dong, Bo; Guo, Huarong

2017-02-01

Coral has strong regeneration ability, which has been applied for coral production and biodiversity protection via tissue ball (TB) culture. However, the architecture, morphological processes, and effects of environmental factors on TB formation have not been well investigated. In this study, we first observed TB formation from the cutting tentacle of scleractinia coral Goniopora lobata and uncovered its inner organization and architecture by confocal microscopy. We then found that the cutting tentacle TB could self-organize and reform a solid TB (sTB) in the culture media. Using chemical drug treatment and dissection manipulation approaches, we demonstrated that the mechanical forces for bending and rounding of the cutting fragments came from the epithelial cells, and the cilia of epithelial cell played indispensable roles for the rounding process. Environmental stress experiments showed that high temperature, not CO 2 -induced acidification, affected TB and sTB formation. However, the combination of high temperature and acidification caused additional severe effects on sTB reformation. Our studies indicate that coral TB has strong regeneration ability and therefore could serve as a new model to further explore the molecular mechanism of TB formation and the effects of environmental stresses on coral survival and regeneration.

The Drosophila Duox maturation factor is a key component of a positive feedback loop that sustains regeneration signaling.

PubMed

Khan, Sumbul Jawed; Abidi, Syeda Nayab Fatima; Skinner, Andrea; Tian, Yuan; Smith-Bolton, Rachel K

2017-07-01

Regenerating tissue must initiate the signaling that drives regenerative growth, and sustain that signaling long enough for regeneration to complete. How these key signals are sustained is unclear. To gain a comprehensive view of the changes in gene expression that occur during regeneration, we performed whole-genome mRNAseq of actively regenerating tissue from damaged Drosophila wing imaginal discs. We used genetic tools to ablate the wing primordium to induce regeneration, and carried out transcriptional profiling of the regeneration blastema by fluorescently labeling and sorting the blastema cells, thus identifying differentially expressed genes. Importantly, by using genetic mutants of several of these differentially expressed genes we have confirmed that they have roles in regeneration. Using this approach, we show that high expression of the gene moladietz (mol), which encodes the Duox-maturation factor NIP, is required during regeneration to produce reactive oxygen species (ROS), which in turn sustain JNK signaling during regeneration. We also show that JNK signaling upregulates mol expression, thereby activating a positive feedback signal that ensures the prolonged JNK activation required for regenerative growth. Thus, by whole-genome transcriptional profiling of regenerating tissue we have identified a positive feedback loop that regulates the extent of regenerative growth.

The Drosophila Duox maturation factor is a key component of a positive feedback loop that sustains regeneration signaling

PubMed Central

Skinner, Andrea; Tian, Yuan

2017-01-01

Regenerating tissue must initiate the signaling that drives regenerative growth, and sustain that signaling long enough for regeneration to complete. How these key signals are sustained is unclear. To gain a comprehensive view of the changes in gene expression that occur during regeneration, we performed whole-genome mRNAseq of actively regenerating tissue from damaged Drosophila wing imaginal discs. We used genetic tools to ablate the wing primordium to induce regeneration, and carried out transcriptional profiling of the regeneration blastema by fluorescently labeling and sorting the blastema cells, thus identifying differentially expressed genes. Importantly, by using genetic mutants of several of these differentially expressed genes we have confirmed that they have roles in regeneration. Using this approach, we show that high expression of the gene moladietz (mol), which encodes the Duox-maturation factor NIP, is required during regeneration to produce reactive oxygen species (ROS), which in turn sustain JNK signaling during regeneration. We also show that JNK signaling upregulates mol expression, thereby activating a positive feedback signal that ensures the prolonged JNK activation required for regenerative growth. Thus, by whole-genome transcriptional profiling of regenerating tissue we have identified a positive feedback loop that regulates the extent of regenerative growth. PMID:28753614

Laser therapy of muscle injuries.

PubMed

Dawood, Munqith S; Al-Salihi, Anam Rasheed; Qasim, Amenah Wala'a

2013-05-01

Low-level lasers are used in general therapy and healing process due to their good photo-bio-stimulation effects. In this paper, the effects of diode laser and Nd:YAG laser on the healing process of practically managed skeletal muscle trauma has been successfully studied. Standard impact trauma was induced by using a specially designed mechanical device. The impacted muscle was left for 3 days for complete development of blunt trauma. After that it was irradiated by five laser sessions for 5 days. Two types of lasers were used; 785-nm diode laser and 1.064-nm Nd:YAG laser, both in continuous and pulsed modes. A special electronic circuit was designed and implemented to modulate the diode laser for this purpose. Tissue samples of crushed skeletal muscle have been dissected from the injured irradiated muscle then bio-chemically analyzed for the regeneration of contractile and collagenous proteins using Lowry assay for protein determination and Reddy and Enwemeka assay for hydroxyproline determination. The results showed that both lasers stimulate the regeneration capability of traumatized skeletal muscle. The diode laser in CW and pulsed modes showed better results than the Nd:YAG in accelerating the preservation of the normal tissue content of collagenous and contractile proteins beside controlling the regeneration of non-functional fibrous tissue. This study proved that the healing achieved by the laser treatment was faster than the control group by 15-20 days.

Innate immune system and tissue regeneration in planarians: an area ripe for exploration.

PubMed

Peiris, T Harshani; Hoyer, Katrina K; Oviedo, Néstor J

2014-08-01

The immune system has been implicated as an important modulator of tissue regeneration. However, the mechanisms driving injury-induced immune response and tissue repair remain poorly understood. For over 200 years, planarians have been a classical model for studies on tissue regeneration, but the planarian immune system and its potential role in repair is largely unknown. We found through comparative genomic analysis and data mining that planarians contain many potential homologs of the innate immune system that are activated during injury and repair of adult tissues. These findings support the notion that the relationship between adult tissue repair and the immune system is an ancient feature of basal Bilateria. Further analysis of the planarian immune system during regeneration could potentially add to our understanding of how the innate immune system and inflammatory responses interplay with regenerative signals to induce scar-less tissue repair in the context of the adult organism. Copyright © 2014 Elsevier Ltd. All rights reserved.

Teleost fish as a model system to study successful regeneration of the central nervous system.

PubMed

Zupanc, Günther K H; Sîrbulescu, Ruxandra F

2013-01-01

Traumatic brain injury and spinal cord injury are devastating conditions that may result in death or long-term disability. A promising strategy for the development of effective cell replacement therapies involves the study of regeneration-competent organisms. Among this group, teleost fish are distinguished by their excellent potential to regenerate nervous tissue and to regain function after injury to the central nervous system. In this chapter, we summarize our current understanding of the cellular processes that mediate this regenerative potential, and we show that several of these processes are shared with the normal development of the intact central nervous system; we describe how the spontaneous self-repair of the teleostean central nervous system leads to functional recovery, at physiological and behavioral levels; we discuss the possible function of molecular factors associated with the degenerative and regenerative processes after injury; and, finally, we speculate on evolutionary aspects of adult neurogenesis and neuronal regeneration, and on how a better understanding of these aspects could catalyze the development of therapeutic strategies to overcome the regenerative limits of the mammalian CNS.

Experimental study of reparative regeneration processes in the wound treated with bioactive dressings.

PubMed

Chekmareva, I A

2002-02-01

Quantitative and structural functional analysis of granulation tissue cells during treatment with protein-polysaccharide dressing Collahit F was carried out. The preparation effectively cleansed the wound from detritus, prevented secondary infection due to stimulation of the functional activity of macrophages and due to the effect of its antiseptic component (furagin), and stimulated proliferative activity of fibroblasts and granulation tissue microvessels on day 5 of treatment, thus promoting repair processes in the wound.

Periodontal regeneration using engineered bone marrow mesenchymal stromal cells.

PubMed

Yang, Yi; Rossi, Fabio M V; Putnins, Edward E

2010-11-01

Regeneration of lost periodontium is a challenge in that both hard (alveolar bone, cementum) and soft (periodontal ligament) connective tissues need to be restored to their original architecture. Bone marrow mesenchymal stromal cells (BM-MSCs) appear to be an attractive candidate for connective tissue regeneration. We hypothesized that BM-MSCs are able to sense biological cues from the local microenvironment and organize appropriately to contribute to the regeneration of both soft and hard periodontal connective tissues. To test this hypothesis, we transplanted GFP(+) rat BM-MSCs expanded ex vivo on microcarrier gelatin beads into a surgically created rat periodontal defect. After three weeks, evidence of regeneration of bone, cementum and periodontal ligament was observed in both transplanted and control animals. However, the animals that received BM-MSCs regenerated significantly greater new bone. In addition, the animals that had received the cells and beads transplant had significantly more appropriately orientated periodontal ligament fibers, indicative of functional restoration. Finally, donor-derived BM-MSCs were found integrated in newly formed bone, cementum and periodontal ligament, suggesting that they can directly contribute to the regeneration of cells of these tissues. Copyright © 2010 Elsevier Ltd. All rights reserved.

Controlled release of drugs in electrosprayed nanoparticles for bone tissue engineering.

PubMed

Jayaraman, Praveena; Gandhimathi, Chinnasamy; Venugopal, Jayarama Reddy; Becker, David Laurence; Ramakrishna, Seeram; Srinivasan, Dinesh Kumar

2015-11-01

Generating porous topographic substrates, by mimicking the native extracellular matrix (ECM) to promote the regeneration of damaged bone tissues, is a challenging process. Generally, scaffolds developed for bone tissue regeneration support bone cell growth and induce bone-forming cells by natural proteins and growth factors. Limitations are often associated with these approaches such as improper scaffold stability, and insufficient cell adhesion, proliferation, differentiation, and mineralization with less growth factor expression. Therefore, the use of engineered nanoparticles has been rapidly increasing in bone tissue engineering (BTE) applications. The electrospray technique is advantageous over other conventional methods as it generates nanomaterials of particle sizes in the micro/nanoscale range. The size and charge of the particles are controlled by regulating the polymer solution flow rate and electric voltage. The unique properties of nanoparticles such as large surface area-to-volume ratio, small size, and higher reactivity make them promising candidates in the field of biomedical engineering. These nanomaterials are extensively used as therapeutic agents and for drug delivery, mimicking ECM, and restoring and improving the functions of damaged organs. The controlled and sustained release of encapsulated drugs, proteins, vaccines, growth factors, cells, and nucleotides from nanoparticles has been well developed in nanomedicine. This review provides an insight into the preparation of nanoparticles by electrospraying technique and illustrates the use of nanoparticles in drug delivery for promoting bone tissue regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

Surface Entrapment of Fibronectin on Electrospun PLGA Scaffolds for Periodontal Tissue Engineering

PubMed Central

Gritsch, Kerstin; Salles, Vincent; Attik, Ghania N.; Grosgogeat, Brigitte

2014-01-01

Abstract Nowadays, the challenge in the tissue engineering field consists in the development of biomaterials designed to regenerate ad integrum damaged tissues. Despite the current use of bioresorbable polyesters such as poly(l-lactide) (PLA), poly(d,l-lactide-co-glycolide) (PLGA), and poly-ɛ-caprolactone in soft tissue regeneration researches, their hydrophobic properties negatively influence the cell adhesion. Here, to overcome it, we have developed a fibronectin (FN)-functionalized electrospun PLGA scaffold for periodontal ligament regeneration. Functionalization of electrospun PLGA scaffolds was performed by alkaline hydrolysis (0.1 or 0.01 M NaOH). Then, hydrolyzed scaffolds were coated by simple deposition of an FN layer (10 μg/mL). FN coating was evidenced by X-ray photoelectron analysis. A decrease of contact angle and greater cell adhesion to hydrolyzed, FN-coated PLGA scaffolds were noticed. Suitable degradation behavior without pH variations was observed for all samples up to 28 days. All treated materials presented strong shrinkage, fiber orientation loss, and collapsed fibers. However, functionalization process using 0.01 M NaOH concentration resulted in unchanged scaffold porosity, preserved chemical composition, and similar mechanical properties compared with untreated scaffolds. The proposed simplified method to functionalize electrospun PLGA fibers is an efficient route to make polyester scaffolds more biocompatible and shows potential for tissue engineering. PMID:24940563

Periodontal Wound Healing Responses to Varying Oxygen Concentrations and Atmospheric Pressures.

DTIC Science & Technology

1986-05-01

Presumably, epithelial and gingival connective tissue exclusion allowed periodontal ligament cells to repopulate the wound and to regenerate a new...However, it seems clear that the periodontal ligament cells provide a major source of connective tissue attachment and regeneration (Nyman et al., 1982a...Connective Tissue Regeneration to Periodontally Diseased Teeth. J. Perio. Res. 15:1. Davis, J. C., Dunn, J. M., Gates, G. A. and Heimbach, R. D. 1979

Fluoride Ion Regeneration of Cyclosarin (Gf) from Minipig Tissue and Fluids Following Whole Body GF Vapor Exposure

DTIC Science & Technology

2006-11-01

Quantitation of organophosphorus nerve agent metabolites in human urine using isotope dilution gas chromatography- tandem mass spectrometry. J. Anal...Recent developments to improve nerve agent biomarker techniques include methods for measuring fluoride regenerated Sarin (GB) in blood and tissue...Our efforts extend the fluoride ion regeneration method to be able to determine cyclosarin (GF) in red blood cells, plasma, and tissue of minipig

Periodontal and peri-implant bone regeneration: clinical and histologic observations.

PubMed

Artzi, Z; Zohar, R; Tal, H

1997-02-01

The principle of guided tissue regeneration by barrier membranes to restore lost periodontal tissue around natural teeth has also been used around osseointegrated implants in an attempt to restore alveolar ridge defects. While most periodontal procedures in the literature describe root coverage by mucogingival surgery, which achieves healing through soft tissue attachment, regeneration of denuded root surfaces is performed by guided tissue regeneration using expanded polytetrafluoroethylene barrier membranes and demineralized freeze-dried bone allografts as inductive/conductive materials. In this study the technique is applied in two partially exposed cylindrical hydroxyapatite-coated implants in extraction sites in one patient. Surgical reentry in both sites is presented, with histologic examination revealing new bone formation on the exposed root surface and the hydroxyapatite-coated implants.

The cellular and molecular mechanisms of tissue repair and regeneration as revealed by studies in Xenopus

PubMed Central

Li, Jingjing; Zhang, Siwei

2016-01-01

Abstract Survival of any living organism critically depends on its ability to repair and regenerate damaged tissues and/or organs during its lifetime following injury, disease, or aging. Various animal models from invertebrates to vertebrates have been used to investigate the molecular and cellular mechanisms of wound healing and tissue regeneration. It is hoped that such studies will form the framework for identifying novel clinical treatments that will improve the healing and regenerative capacity of humans. Amongst these models, Xenopus stands out as a particularly versatile and powerful system. This review summarizes recent findings using this model, which have provided fundamental knowledge of the mechanisms responsible for efficient and perfect tissue repair and regeneration. PMID:27800170

Modelling the impact of altered axonal morphometry on the response of regenerative nervous tissue to electrical stimulation through macro-sieve electrodes.

PubMed

Zellmer, Erik R; MacEwan, Matthew R; Moran, Daniel W

2018-04-01

Regenerated peripheral nervous tissue possesses different morphometric properties compared to undisrupted nerve. It is poorly understood how these morphometric differences alter the response of the regenerated nerve to electrical stimulation. In this work, we use computational modeling to explore the electrophysiological response of regenerated and undisrupted nerve axons to electrical stimulation delivered by macro-sieve electrodes (MSEs). A 3D finite element model of a peripheral nerve segment populated with mammalian myelinated axons and implanted with a macro-sieve electrode has been developed. Fiber diameters and morphometric characteristics representative of undisrupted or regenerated peripheral nervous tissue were assigned to core conductor models to simulate the two tissue types. Simulations were carried out to quantify differences in thresholds and chronaxie between undisrupted and regenerated fiber populations. The model was also used to determine the influence of axonal caliber on recruitment thresholds for the two tissue types. Model accuracy was assessed through comparisons with in vivo recruitment data from chronically implanted MSEs. Recruitment thresholds of individual regenerated fibers with diameters  >2 µm were found to be lower compared to same caliber undisrupted fibers at electrode to fiber distances of less than about 90-140 µm but roughly equal or higher for larger distances. Caliber redistributions observed in regenerated nerve resulted in an overall increase in average recruitment thresholds and chronaxie during whole nerve stimulation. Modeling results also suggest that large diameter undisrupted fibers located close to a longitudinally restricted current source such as the MSE have higher average recruitment thresholds compared to small diameter fibers. In contrast, large diameter regenerated nerve fibers located in close proximity of MSE sites have, on average, lower recruitment thresholds compared to small fibers. Utilizing regenerated fiber morphometry and caliber distributions resulted in accurate predictions of in vivo recruitment data. Our work uses computational modeling to show how morphometric differences between regenerated and undisrupted tissue results in recruitment threshold discrepancies, quantifies these differences, and illustrates how large undisrupted nerve fibers close to longitudinally restricted current sources have higher recruitment thresholds compared to adjacently positioned smaller fibers while the opposite is true for large regenerated fibers.

Modelling the impact of altered axonal morphometry on the response of regenerative nervous tissue to electrical stimulation through macro-sieve electrodes

NASA Astrophysics Data System (ADS)

Zellmer, Erik R.; MacEwan, Matthew R.; Moran, Daniel W.

2018-04-01

Objective. Regenerated peripheral nervous tissue possesses different morphometric properties compared to undisrupted nerve. It is poorly understood how these morphometric differences alter the response of the regenerated nerve to electrical stimulation. In this work, we use computational modeling to explore the electrophysiological response of regenerated and undisrupted nerve axons to electrical stimulation delivered by macro-sieve electrodes (MSEs). Approach. A 3D finite element model of a peripheral nerve segment populated with mammalian myelinated axons and implanted with a macro-sieve electrode has been developed. Fiber diameters and morphometric characteristics representative of undisrupted or regenerated peripheral nervous tissue were assigned to core conductor models to simulate the two tissue types. Simulations were carried out to quantify differences in thresholds and chronaxie between undisrupted and regenerated fiber populations. The model was also used to determine the influence of axonal caliber on recruitment thresholds for the two tissue types. Model accuracy was assessed through comparisons with in vivo recruitment data from chronically implanted MSEs. Main results. Recruitment thresholds of individual regenerated fibers with diameters  >2 µm were found to be lower compared to same caliber undisrupted fibers at electrode to fiber distances of less than about 90-140 µm but roughly equal or higher for larger distances. Caliber redistributions observed in regenerated nerve resulted in an overall increase in average recruitment thresholds and chronaxie during whole nerve stimulation. Modeling results also suggest that large diameter undisrupted fibers located close to a longitudinally restricted current source such as the MSE have higher average recruitment thresholds compared to small diameter fibers. In contrast, large diameter regenerated nerve fibers located in close proximity of MSE sites have, on average, lower recruitment thresholds compared to small fibers. Utilizing regenerated fiber morphometry and caliber distributions resulted in accurate predictions of in vivo recruitment data. Significance. Our work uses computational modeling to show how morphometric differences between regenerated and undisrupted tissue results in recruitment threshold discrepancies, quantifies these differences, and illustrates how large undisrupted nerve fibers close to longitudinally restricted current sources have higher recruitment thresholds compared to adjacently positioned smaller fibers while the opposite is true for large regenerated fibers.

Gene expression profiles characterize early graft response in living donor small bowel transplantation: a case report.

PubMed

Bradley, S P; Pahari, M; Uknis, M E; Rastellini, C; Cicalese, L

2006-01-01

The cellular and histological events that occur during the regeneration process in invertebrates have been studied in the field of visceral regeneration. We would like to explore the molecular aspects of the regeneration process in the small intestine. The aim of this study was to characterize the gene expression profiles of the intestinal graft to identify which genes may have a role in regeneration of graft tissue posttransplant. In a patient undergoing living related small bowel transplantation (LRSBTx) in our institution, mucosal biopsies were obtained from the recipient intestine and donor graft at the time of transplant and at weeks 1, 2, 3, and 6 posttransplant. Total RNA was isolated from sample biopsies followed by gene expression profiles determined from the replicate samples (n = 3) for each biopsy using the Affymetrix U133 Plus 2.0 Human GeneChip set. Two profiles were obtained from the data. One profile showed rapid increase of 45 genes immediately after transplant by week 1 with significant changes (P < .05) greater than threefold including the chemokine CXC9 and glutathione-related stress factors, GPX2 and GSTA4. The second profile identified 133 genes that were significantly decreased by threefold or greater immediately after transplant week 1, including UCC1, the human homolog of the Ependymin gene. We have identified two gene expression profiles representing early graft responses to small bowel transplantation. These profiles will serve to identify and study those genes whose products may play a role in accelerating tissue regeneration following segmental LRSBTx.

Plasma Rich in Growth Factors for the Treatment of Ocular Surface Diseases.

PubMed

Anitua, Eduardo; Muruzabal, Francisco; de la Fuente, María; Merayo, Jesús; Durán, Juan; Orive, Gorka

2016-07-01

The purpose of this work is to describe and review the technology of plasma rich in growth factors (PRGF), a novel blood derivative product, in the treatment of ocular surface disorders. To demonstrate the importance of this technology in the treatment of ocular pathologies, a thorough review of the preclinical and clinical literature results obtained following use of the different therapeutic formulations of PRGF was carried out. A literature search for applications of PGRF plasma in the ophthalmology field was carried out using the PubMed database. PRGF involves the use of patient's own biologically active proteins, growth factors, and biomaterial scaffolds for therapeutic purposes. This procedural technology is gaining interest in regenerative medicine due to its potential to stimulate and accelerate the tissue healing processes. The versatility and biocompatibility of this technology opens the door to a personalized medicine on ocular tissue regeneration. This review discusses the state of the art of the new treatments and technologies developed to promote ocular surface tissue regeneration. The standardized protocol that has been developed to source eye drops from PRGF technology is also described. The preclinical research, together with the most relevant clinical applications are summarized and discussed. The preliminary results suggest that the use of PRGF to enhance ocular tissue regeneration is safe and efficient.

detrimentally affects tissue regeneration of Red Sea corals

NASA Astrophysics Data System (ADS)

Horwitz, Rael; Fine, Maoz

2014-09-01

Ocean acidification (OA) from rising atmospheric carbon dioxide (CO2) is threatening the future of coral reef ecosystems. Mounting experimental evidence suggests that OA negatively impacts fundamental life functions of scleractinian corals, including growth and sexual reproduction. Although regeneration is regarded as a chief life function in scleractinian corals and essential to maintain the colony's integrity, the effect of OA on regeneration processes has not yet been investigated. To evaluate the effects of OA on regeneration, the common Indo-Pacific corals Porites sp., Favia favus, Acropora eurystoma, and Stylophora pistillata were inflicted with lesions (314-350 mm2, depending on species) and incubated in different pCO2: (1) ambient seawater (400 µatm, pH 8.1), (2) intermediate (1,800 µatm, pH 7.6), and (3) high (4,000 µatm, pH 7.3) for extended periods of time (60-120 d). While all coral species after 60 d had significantly higher tissue regeneration in ambient conditions as compared to the intermediate and high treatments, reduction in regeneration rate was more pronounced in the slow-growing massive Porites sp. and F. favus than the relatively fast-growing, branching S. pistillata and A. eurystoma. This coincided with reduced tissue biomass of Porites sp., F. favus, and A. eurystoma in higher pCO2, but not in S. pistillata. Porites sp., F. favus, and S. pistillata also experienced a decrease in Symbiodinium density in higher pCO2, while in A. eurystoma there was no change. We hypothesize that a lowered regenerative capacity under elevated pCO2 may be related to resource trade-offs, energy cost of acid/base regulation, and/or decrease in total energy budget. This is the first study to demonstrate that elevated pCO2 could have a compounding influence on coral regeneration following injury, potentially affecting the capacity of reef corals to recover following physical disturbance.

Molecular signatures that correlate with induction of lens regeneration in newts: lessons from proteomic analysis.

PubMed

Sousounis, Konstantinos; Bhavsar, Rital; Looso, Mario; Krüger, Marcus; Beebe, Jessica; Braun, Thomas; Tsonis, Panagiotis A

2014-12-11

Amphibians have the remarkable ability to regenerate missing body parts. After complete removal of the eye lens, the dorsal but not the ventral iris will transdifferentiate to regenerate an exact replica of the lost lens. We used reverse-phase nano-liquid chromatography followed by mass spectrometry to detect protein concentrations in dorsal and ventral iris 0, 4, and 8 days post-lentectomy. We performed gene expression comparisons between regeneration and intact timepoints as well as between dorsal and ventral iris. Our analysis revealed gene expression patterns associated with the ability of the dorsal iris for transdifferentiation and lens regeneration. Proteins regulating gene expression and various metabolic processes were enriched in regeneration timepoints. Proteins involved in extracellular matrix, gene expression, and DNA-associated functions like DNA repair formed a regeneration-related protein network and were all up-regulated in the dorsal iris. In addition, we investigated protein concentrations in cultured dorsal (transdifferentiation-competent) and ventral (transdifferentiation-incompetent) iris pigmented epithelial (IPE) cells. Our comparative analysis revealed that the ability of dorsal IPE cells to keep memory of their tissue of origin and transdifferentiation is associated with the expression of proteins that specify the dorso-ventral axis of the eye as well as with proteins found highly expressed in regeneration timepoints, especially 8 days post-lentectomy. The study deepens our understanding in the mechanism of regeneration by providing protein networks and pathways that participate in the process.

Distinct profiles of expressed sequence tags during intestinal regeneration in the sea cucumber Holothuria glaberrima

PubMed Central

Rojas-Cartagena, Carmencita; Ortíz-Pineda, Pablo; Ramírez-Gómez, Francisco; Suárez-Castillo, Edna C.; Matos-Cruz, Vanessa; Rodríguez, Carlos; Ortíz-Zuazaga, Humberto; García-Arrarás, José E.

2010-01-01

Repair and regeneration are key processes for tissue maintenance, and their disruption may lead to disease states. Little is known about the molecular mechanisms that underline the repair and regeneration of the digestive tract. The sea cucumber Holothuria glaberrima represents an excellent model to dissect and characterize the molecular events during intestinal regeneration. To study the gene expression profile, cDNA libraries were constructed from normal, 3-day, and 7-day regenerating intestines of H. glaberrima. Clones were randomly sequenced and queried against the nonredundant protein database at the National Center for Biotechnology Information. RT-PCR analyses were made of several genes to determine their expression profile during intestinal regeneration. A total of 5,173 sequences from three cDNA libraries were obtained. About 46.2, 35.6, and 26.2% of the sequences for the normal, 3-days, and 7-days cDNA libraries, respectively, shared significant similarity with known sequences in the protein database of GenBank but only present 10% of similarity among them. Analysis of the libraries in terms of functional processes, protein domains, and most common sequences suggests that a differential expression profile is taking place during the regeneration process. Further examination of the expressed sequence tag dataset revealed that 12 putative genes are differentially expressed at significant level (R > 6). Experimental validation by RT-PCR analysis reveals that at least three genes (unknown C-4677-1, melanotransferrin, and centaurin) present a differential expression during regeneration. These findings strongly suggest that the gene expression profile varies among regeneration stages and provide evidence for the existence of differential gene expression. PMID:17579180

[Research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration].

PubMed

Liang, Hang; Deng, Xiangyu; Shao, Zengwu

2017-10-01

To summarize the research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration and deduce the therapeutic potential of endogenous repair for intervertebral disc degeneration. The original articles about intervertebral disc endogenous stem cells for intervertebral disc regeneration were extensively reviewed; the reparative potential in vivo and the extraction and identification in vitro of intervertebral disc endogenous stem cells were analyzed; the prospect of endogenous stem cells for intervertebral disc regeneration was predicted. Stem cell niche present in the intervertebral discs, from which stem cells migrate to injured tissues and contribute to tissues regeneration under certain specific microenvironment. Moreover, the migration of stem cells is regulated by chemokines system. Tissue specific progenitor cells have been identified and successfully extracted and isolated. The findings provide the basis for biological therapy of intervertebral disc endogenous stem cells. Intervertebral disc endogenous stem cells play a crucial role in intervertebral disc regeneration. Therapeutic strategy of intervertebral disc endogenous stem cells is proven to be a promising biological approach for intervertebral disc regeneration.

Eye Absence Does Not Regulate Planarian Stem Cells during Eye Regeneration.

PubMed

LoCascio, Samuel A; Lapan, Sylvain W; Reddien, Peter W

2017-02-27

Dividing cells called neoblasts contain pluripotent stem cells and drive planarian flatworm regeneration from diverse injuries. A long-standing question is whether neoblasts directly sense and respond to the identity of missing tissues during regeneration. We used the eye to investigate this question. Surprisingly, eye removal was neither sufficient nor necessary for neoblasts to increase eye progenitor production. Neoblasts normally increase eye progenitor production following decapitation, facilitating regeneration. Eye removal alone, however, did not induce this response. Eye regeneration following eye-specific resection resulted from homeostatic rates of eye progenitor production and less cell death in the regenerating eye. Conversely, large head injuries that left eyes intact increased eye progenitor production. Large injuries also non-specifically increased progenitor production for multiple uninjured tissues. We propose a model for eye regeneration in which eye tissue production by planarian stem cells is not directly regulated by the absence of the eye itself. Copyright © 2017 Elsevier Inc. All rights reserved.

Advances in Regenerative Orthopaedics

PubMed Central

Evans, Christopher H.

2013-01-01

Orthopaedic injuries are very common and a source of much misery and economic stress. Several relevant tissues, such as cartilage, meniscus and intra-articular ligaments, do not heal. And even bone, which normally regenerates spontaneously, can fail to mend. The regeneration of orthopaedic tissues requires four key components: cells, morphogenetic signals, scaffolds and an appropriate mechanical environment. Although differentiated cells from the tissue in question can be used, most cellular research focuses on the use mesenchymal stem cells (MSCs). These can be retrieved from many different tissues, and one unresolved question is the degree to which the origin of the cells matters. Embryonic and induced, pluripotential stem cells are also under investigation. Morphogenetic signals are most frequently supplied by individual, recombinant growth factors or native mixtures provided by, for instance, platelet-rich plasma; MSCs are also a rich source of trophic factors. Obstacles to the sustained delivery of individual growth factors can be addressed by gene transfer or smart scaffolds, but we still lack detailed, necessary information on which delivery profiles are needed. Scaffolds may be based upon natural products, synthetic materials, or devitalized extracellular matrix. Strategies to combine these components to regenerate tissue can follow traditional tissue engineering practices, but these are costly, cumbersome and not well suited to treating large numbers of individuals. More expeditious approaches make full use of intrinsic biological processes in vivo to avoid the need for ex vivo expansion of autologous cells and multiple procedures. Clinical translation remains a bottleneck. PMID:24182709

Role of adipose-derived stem cells in wound healing.

PubMed

Hassan, Waqar Ul; Greiser, Udo; Wang, Wenxin

2014-01-01

Impaired wound healing remains a challenge to date and causes debilitating effects with tremendous suffering. Recent advances in tissue engineering approaches in the area of cell therapy have provided promising treatment options to meet the challenges of impaired skin wound healing such as diabetic foot ulcers. Over the last few years, stem cell therapy has emerged as a novel therapeutic approach for various diseases including wound repair and tissue regeneration. Several different types of stem cells have been studied in both preclinical and clinical settings such as bone marrow-derived stem cells, adipose-derived stem cells (ASCs), circulating angiogenic cells (e.g., endothelial progenitor cells), human dermal fibroblasts, and keratinocytes for wound healing. Adipose tissue is an abundant source of mesenchymal stem cells, which have shown an improved outcome in wound healing studies. ASCs are pluripotent stem cells with the ability to differentiate into different lineages and to secrete paracrine factors initiating tissue regeneration process. The abundant supply of fat tissue, ease of isolation, extensive proliferative capacities ex vivo, and their ability to secrete pro-angiogenic growth factors make them an ideal cell type to use in therapies for the treatment of nonhealing wounds. In this review, we look at the pathogenesis of chronic wounds, role of stem cells in wound healing, and more specifically look at the role of ASCs, their mechanism of action and their safety profile in wound repair and tissue regeneration. © 2014 by the Wound Healing Society.

Effect of x-ray irradiation on maize inbred line B73 tissue cultures and regenerated plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, A.S.; Cheng, D.S.K.; Milcic, J.B.

In order to enhance variation induced by the tissue culture process and to obtain agronomically desirable mutants, friable embryogenic tissue cultures of maize (Zea mays L.) inbred line B73 were x-ray irradiated with 11 doses (0-8.4 kilorads (kR)). Reductions in callus growth rate and embryogenic callus formation occurred with increasing x-ray doses 20 d and 3 months after irradiation. Callus irradiated with 0.8 kR showed a significant increase in growth rate and a 20% increase in embryogenic callus 9 months after irradiation. A total of 230 R/sub 0/ plants were regenerated for evaluation. Pollen fertility and seed set of R/submore » 0/ plants decreased with increasing x-ray dosage. Days to anthesis and plant height of R/sub 0/ plants varied among x-ray treatments but were generally reduced with higher dosages. The number of chromosomal aberrations increased with x-ray dosage. The R/sub 1/ seeds taken from R/sub 0/ plants were also grown and tested for mutant segregation. Plants regenerated from irradiated calli had a two- to 10-fold increase in mutations over plants regenerated from unirradiated control callus. Germination frequency of seeds from R/sub 0/ plants decreased with increasing x-ray dosage. Although chlorophyll mutants were most frequently observed, a number of vigorous plants with earlier anthesis date were also recovered.« less

Endochondral Priming: A Developmental Engineering Strategy for Bone Tissue Regeneration.

PubMed

Freeman, Fiona E; McNamara, Laoise M

2017-04-01

Tissue engineering and regenerative medicine have significant potential to treat bone pathologies by exploiting the capacity for bone progenitors to grow and produce tissue constituents under specific biochemical and physical conditions. However, conventional tissue engineering approaches, which combine stem cells with biomaterial scaffolds, are limited as the constructs often degrade, due to a lack of vascularization, and lack the mechanical integrity to fulfill load bearing functions, and as such are not yet widely used for clinical treatment of large bone defects. Recent studies have proposed that in vitro tissue engineering approaches should strive to simulate in vivo bone developmental processes and, thereby, imitate natural factors governing cell differentiation and matrix production, following the paradigm recently defined as "developmental engineering." Although developmental engineering strategies have been recently developed that mimic specific aspects of the endochondral ossification bone formation process, these findings are not widely understood. Moreover, a critical comparison of these approaches to standard biomaterial-based bone tissue engineering has not yet been undertaken. For that reason, this article presents noteworthy experimental findings from researchers focusing on developing an endochondral-based developmental engineering strategy for bone tissue regeneration. These studies have established that in vitro approaches, which mimic certain aspects of the endochondral ossification process, namely the formation of the cartilage template and the vascularization of the cartilage template, can promote mineralization and vascularization to a certain extent both in vitro and in vivo. Finally, this article outlines specific experimental challenges that must be overcome to further exploit the biology of endochondral ossification and provide a tissue engineering construct for clinical treatment of large bone/nonunion defects and obviate the need for bone tissue graft.

Reconstitution of the myocardium in regenerating newt hearts is preceded by transient deposition of extracellular matrix components.

PubMed

Piatkowski, Tanja; Mühlfeld, Christian; Borchardt, Thilo; Braun, Thomas

2013-07-01

Adult newts efficiently regenerate the heart after injury in a process that involves proliferation of cardiac muscle and nonmuscle cells and repatterning of the myocardium. To analyze the processes that underlie heart regeneration in newts, we characterized the structural changes in the myocardium that allow regeneration after mechanical injury. We found that cardiomyocytes in the damaged ventricle mainly die by necrosis and are removed during the first week after injury, paving the way for the extension of thin myocardial trabeculae, which initially contain only very few cardiomyocytes. During the following 200 days, these thin trabeculae fill up with new cardiomyocytes until the myocardium is fully reconstituted. Interestingly, reconstruction of the newly formed trabeculated network is accompanied by transient deposition of extracellular matrix (ECM) components such as collagen III. We conclude that the ECM is a critical guidance cue for outgrowing and branching trabeculae to reconstruct the trabeculated network, which represents a hallmark of uninjured cardiac tissue in newts.

Ingestion of bacterially expressed double-stranded RNA inhibits gene expression in planarians.

PubMed

Newmark, Phillip A; Reddien, Peter W; Cebrià, Francesc; Sánchez Alvarado, Alejandro

2003-09-30

Freshwater planarian flatworms are capable of regenerating complete organisms from tiny fragments of their bodies; the basis for this regenerative prowess is an experimentally accessible stem cell population that is present in the adult planarian. The study of these organisms, classic experimental models for investigating metazoan regeneration, has been revitalized by the application of modern molecular biological approaches. The identification of thousands of unique planarian ESTs, coupled with large-scale whole-mount in situ hybridization screens, and the ability to inhibit planarian gene expression through double-stranded RNA-mediated genetic interference, provide a wealth of tools for studying the molecular mechanisms that regulate tissue regeneration and stem cell biology in these organisms. Here we show that, as in Caenorhabditis elegans, ingestion of bacterially expressed double-stranded RNA can inhibit gene expression in planarians. This inhibition persists throughout the process of regeneration, allowing phenotypes with disrupted regenerative patterning to be identified. These results pave the way for large-scale screens for genes involved in regenerative processes.

Strategies on process engineering of chondrocyte culture for cartilage tissue regeneration.

PubMed

Mallick, Sarada Prasanna; Rastogi, Amit; Tripathi, Satyavrat; Srivastava, Pradeep

2017-04-01

The current work is an attempt to study the strategies for cartilage tissue regeneration using porous scaffold in wavy walled airlift bioreactor (ALBR). Novel chitosan, poly (L-lactide) and hyaluronic acid based composite scaffold were prepared. The scaffolds were cross-linked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide, N-hydroxysuccinimide and chondroitin sulfate to obtain interconnected 3D microstructure showing excellent biocompatibility, higher cellular differentiation and increased stability. The surface morphology and porosity of the scaffolds were analyzed using scanning electron microscopy (SEM) and mercury intrusion porosimeter and optimized for chondrocyte regeneration. The study shows that the scaffolds were highly porous with pore size ranging from 48 to 180 µm and the porosities in the range 80-92%. Swelling and in vitro degradation studies were performed for the composite scaffolds; by increasing the chitosan: HA ratio in the composite scaffolds, the swelling property increases and stabilizes after 24 h. There was controlled degradation of composite scaffolds for 4 weeks. The uniform chondrocyte distribution in the scaffold using various growth modes in the shake flask and ALBR was studied by glycosaminoglycans (GAG) quantification, MTT assay and mixing time evaluation. The cell culture studies demonstrated that efficient designing of ALBR increases the cartilage regeneration as compared to using a shake flask. The free chondrocyte microscopy and cell attachment were performed by inverted microscope and SEM, and from the study it was confirmed that the cells uniformly attached to the scaffold. This study focuses on optimizing strategies for the culture of chondrocyte using suitable scaffold for improved cartilage tissue regeneration.

Planarian yorkie/YAP functions to integrate adult stem cell proliferation, organ homeostasis and maintenance of axial patterning.

PubMed

Lin, Alexander Y T; Pearson, Bret J

2014-03-01

During adult homeostasis and regeneration, the freshwater planarian must accomplish a constant balance between cell proliferation and cell death, while also maintaining proper tissue and organ size and patterning. How these ordered processes are precisely modulated remains relatively unknown. Here we show that planarians use the downstream effector of the Hippo signaling cascade, yorkie (yki; YAP in vertebrates) to control a diverse set of pleiotropic processes in organ homeostasis, stem cell regulation, regeneration and axial patterning. We show that yki functions to maintain the homeostasis of the planarian excretory (protonephridial) system and to limit stem cell proliferation, but does not affect the differentiation process or cell death. Finally, we show that Yki acts synergistically with WNT/β-catenin signaling to repress head determination by limiting the expression domains of posterior WNT genes and that of the WNT-inhibitor notum. Together, our data show that yki is a key gene in planarians that integrates stem cell proliferation control, organ homeostasis, and the spatial patterning of tissues.

Regenerative Medicine for Periodontal and Peri-implant Diseases.

PubMed

Larsson, L; Decker, A M; Nibali, L; Pilipchuk, S P; Berglundh, T; Giannobile, W V

2016-03-01

The balance between bone resorption and bone formation is vital for maintenance and regeneration of alveolar bone and supporting structures around teeth and dental implants. Tissue regeneration in the oral cavity is regulated by multiple cell types, signaling mechanisms, and matrix interactions. A goal for periodontal tissue engineering/regenerative medicine is to restore oral soft and hard tissues through cell, scaffold, and/or signaling approaches to functional and aesthetic oral tissues. Bony defects in the oral cavity can vary significantly, ranging from smaller intrabony lesions resulting from periodontal or peri-implant diseases to large osseous defects that extend through the jaws as a result of trauma, tumor resection, or congenital defects. The disparity in size and location of these alveolar defects is compounded further by patient-specific and environmental factors that contribute to the challenges in periodontal regeneration, peri-implant tissue regeneration, and alveolar ridge reconstruction. Efforts have been made over the last few decades to produce reliable and predictable methods to stimulate bone regeneration in alveolar bone defects. Tissue engineering/regenerative medicine provide new avenues to enhance tissue regeneration by introducing bioactive models or constructing patient-specific substitutes. This review presents an overview of therapies (e.g., protein, gene, and cell based) and biomaterials (e.g., resorbable, nonresorbable, and 3-dimensionally printed) used for alveolar bone engineering around teeth and implants and for implant site development, with emphasis on most recent findings and future directions. © International & American Associations for Dental Research 2015.

Periodontal tissue regeneration by combined implantation of adipose tissue-derived stem cells and platelet-rich plasma in a canine model.

PubMed

Tobita, Morikuni; Uysal, Cagri A; Guo, Xin; Hyakusoku, Hiko; Mizuno, Hiroshi

2013-12-01

One goal of periodontal therapy is to regenerate periodontal tissues. Stem cells, growth factors and scaffolds and biomaterials are vital for the restoration of the architecture and function of complex tissues. Adipose tissue-derived stem cells (ASCs) are an ideal population of stem cells for practical regenerative medicine. In addition, platelet-rich plasma (PRP) can be useful for its ability to stimulate tissue regeneration. PRP contains various growth factors and may be useful as a cell carrier in stem cell therapies. The purpose of this study was to determine whether a mixture of ASCs and PRP promoted periodontal tissue regeneration in a canine model. Autologous ASCs and PRP were implanted into areas with periodontal tissue defects. Periodontal tissue defects that received PRP alone or non-implantation were also examined. Histologic, immunohistologic and x-ray studies were performed 1 or 2 months after implantation. The amount of newly formed bone and the scale of newly formed cementum in the region of the periodontal tissue defect were analyzed on tissue sections. The areas of newly formed bone and cementum were greater 2 months after implantation of ASCs and PRP than at 1 month after implantation, and the radiopacity in the region of the periodontal tissue defect increased markedly by 2 months after implantation. The ASCs and PRP group exhibited periodontal tissue with the correct architecture, including alveolar bone, cementum-like structures and periodontal ligament-like structures, by 2 months after implantation. These findings suggest that a combination of autologous ASCs and PRP promotes periodontal tissue regeneration that develops the appropriate architecture for this complex tissue. Copyright © 2013 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

The Convergence of Fracture Repair and Stem Cells: Interplay of Genes, Aging, Environmental Factors and Disease

PubMed Central

Hadjiargyrou, Michael; O’Keefe, Regis J

2015-01-01

The complexity of fracture repair makes it an ideal process for studying the interplay between the molecular, cellular, tissue, and organ level events involved in tissue regeneration. Additionally, as fracture repair recapitulates many of the processes that occur during embryonic development, investigations of fracture repair provide insights regarding skeletal embryogenesis. Specifically, inflammation, signaling, gene expression, cellular proliferation and differentiation, osteogenesis, chondrogenesis, angiogenesis, and remodeling represent the complex array of interdependent biological events that occur during fracture repair. Here we review studies of bone regeneration in genetically modified mouse models, during aging, following environmental exposure, and in the setting of disease that provide insights regarding the role of multipotent cells and their regulation during fracture repair. Complementary animal models and ongoing scientific discoveries define an increasing number of molecular and cellular targets to reduce the morbidity and complications associated with fracture repair. Last, some new and exciting areas of stem cell research such as the contribution of mitochondria function, limb regeneration signaling, and microRNA (miRNA) posttranscriptional regulation are all likely to further contribute to our understanding of fracture repair as an active branch of regenerative medicine. PMID:25264148

T Lymphocytes Influence the Mineralization Process of Bone

PubMed Central

El Khassawna, Thaqif; Serra, Alessandro; Bucher, Christian H.; Petersen, Ansgar; Schlundt, Claudia; Könnecke, Ireen; Malhan, Deeksha; Wendler, Sebastian; Schell, Hanna; Volk, Hans-Dieter; Schmidt-Bleek, Katharina; Duda, Georg N.

2017-01-01

Bone is a unique organ able to regenerate itself after injuries. This regeneration requires the local interplay between different biological systems such as inflammation and matrix formation. Structural reconstitution is initiated by an inflammatory response orchestrated by the host immune system. However, the individual role of T cells and B cells in regeneration and their relationship to bone tissue reconstitution remain unknown. Comparing bone and fracture healing in animals with and without mature T and B cells revealed the essential role of these immune cells in determining the tissue mineralization and thus the bone quality. Bone without mature T and B cells is stiffer when compared to wild-type bone thus lacking the elasticity that helps to absorb forces, thus preventing fractures. In-depth analysis showed dysregulations in collagen deposition and osteoblast distribution upon lack of mature T and B cells. These changes in matrix deposition have been correlated with T cells rather than B cells within this study. This work presents, for the first time, a direct link between immune cells and matrix formation during bone healing after fracture. It illustrates specifically the role of T cells in the collagen organization process and the lack thereof in the absence of T cells. PMID:28596766

Low-level laser therapy (LLLT) reduces inflammatory infiltrate and enhances skeletal muscle repair: Histomorphometric parameters

NASA Astrophysics Data System (ADS)

Paiva-Oliveira, E. L.; Lima, N. C.; Silva, P. H.; Sousa, N. T. A.; Barbosa, F. S.; Orsini, M.; Silva, J. G.

2012-09-01

Low level laser therapy (LLLT) has been suggested as an effective therapeutics in inflammatory processes modulation and tissue repairing. However, there is a lack of studies that analyze the anti-inflammatory effects of the infrared lasers in muscular skeletal injury. The aim of this study was to investigate the effects of low-level laser therapy 904 nm in the repair process of skeletal muscle tissue. Swiss mice were submitted to cryoinjury and divided in test (LLLT-treated) and control groups. Histological sections were stained with hematoxylin-eosin to assess general morphology and inflammatory influx, and Picrossirus to quantify collagen fibers deposition. Our results showed significant reduction in inflammatory infiltrated in irradiated mice after 4 days of treatment compared to control ( p = 0.01). After 8 days, the irradiated group showed high levels at regenerating myofibers with significant statistically differences in relation at control group ( p < 0.01). Collagen deposition was significantly increased in the final stages of regeneration at test group, when compared with control group ( p = 0.05). Our data suggests that LLLT reduces the inflammatory response in the initial stages of injury and accelerates the process of muscular tissue repair.

Three-dimensional bioprinting of cell-laden constructs with polycaprolactone protective layers for using various thermoplastic polymers.

PubMed

Kim, Byoung Soo; Jang, Jinah; Chae, Suhun; Gao, Ge; Kong, Jeong-Sik; Ahn, Minjun; Cho, Dong-Woo

2016-08-22

Three-dimensional (3D) cell-printed constructs have been recognized as promising biological substitutes for tissue/organ regeneration. They provide tailored physical properties and biological cues via multi-material printing process. In particular, hybrid bioprinting, enabling to use biodegradable synthetic polymers as framework, has been an attractive method to support weak hydrogels. The constructs with controlled architecture and high shape fidelity were fabricated through this method, depositing spatial arrangement of multi-cell types into microscale constructs. Among biodegradable synthetic polymers, polycaprolactone (PCL) has been commonly chosen in fabrication of cell-printed constructs because of its low melting temperature of 60 °C to be dispensed with extrusion-based bioprinting system. However, in addition to PCL, various synthetic polymers have been widely applied for tissue regeneration. These polymers have distinctive characteristics essential for tissue/organ regeneration. Nevertheless, it is difficult to use some polymers, such as poly (lactic-co-glycolic acid) (PLGA) and polylactic acid (PLA) with 3D bioprinting technology because of their high melting temperature to be dispensed, which can result in thermal damage to the cells in the printed constructs during the fabrication process. We present a novel bioprinting method to use various synthetic polymers in fabrication of cell-printed constructs. PCL was introduced as a protective layer to prevent thermal damage caused by high temperature of polymers during fabrication. Remarkable improvement in cellular activities in the printed constructs with PCL layers was observed compared with the construct without PCL. This bioprinting method can be applied to fabricate more tissue-like constructs through the use of various biomaterials.

Stem Cells in the Face: Tooth Regeneration and Beyond

PubMed Central

Mao, Jeremy J.; Robey, Pamela G.; Prockop, Darwin J.

2014-01-01

Postnatal orofacial tissues contain rare cells that exhibit stem/progenitor cell properties. Despite a tremendous unmet clinical need for regeneration of tissues lost in congenital anomalies, infections, trauma or tumor resection, how orofacial stem/progenitor cells contribute to tissue development, pathogenesis and regeneration is largely a mystery. This perspective article critically analyzes the current status of orofacial stem/progenitor cells, identifies gaps in our understanding and highlights pathways for the development of regenerative therapies. PMID:22958928

Bone Regeneration Based on Tissue Engineering Conceptions — A 21st Century Perspective

PubMed Central

Henkel, Jan; Woodruff, Maria A.; Epari, Devakara R.; Steck, Roland; Glatt, Vaida; Dickinson, Ian C.; Choong, Peter F. M.; Schuetz, Michael A.; Hutmacher, Dietmar W.

2013-01-01

The role of Bone Tissue Engineering in the field of Regenerative Medicine has been the topic of substantial research over the past two decades. Technological advances have improved orthopaedic implants and surgical techniques for bone reconstruction. However, improvements in surgical techniques to reconstruct bone have been limited by the paucity of autologous materials available and donor site morbidity. Recent advances in the development of biomaterials have provided attractive alternatives to bone grafting expanding the surgical options for restoring the form and function of injured bone. Specifically, novel bioactive (second generation) biomaterials have been developed that are characterised by controlled action and reaction to the host tissue environment, whilst exhibiting controlled chemical breakdown and resorption with an ultimate replacement by regenerating tissue. Future generations of biomaterials (third generation) are designed to be not only osteoconductive but also osteoinductive, i.e. to stimulate regeneration of host tissues by combining tissue engineering and in situ tissue regeneration methods with a focus on novel applications. These techniques will lead to novel possibilities for tissue regeneration and repair. At present, tissue engineered constructs that may find future use as bone grafts for complex skeletal defects, whether from post-traumatic, degenerative, neoplastic or congenital/developmental “origin” require osseous reconstruction to ensure structural and functional integrity. Engineering functional bone using combinations of cells, scaffolds and bioactive factors is a promising strategy and a particular feature for future development in the area of hybrid materials which are able to exhibit suitable biomimetic and mechanical properties. This review will discuss the state of the art in this field and what we can expect from future generations of bone regeneration concepts. PMID:26273505

Carbon Nanoparticle Enhance Photoacoustic Imaging and Therapy for Bone Tissue Engineering

NASA Astrophysics Data System (ADS)

Talukdar, Yahfi

Healing critical sized bone defects has been a challenge that led to innovations in tissue engineering scaffolds and biomechanical stimulations that enhance tissue regeneration. Carbon nanocomposite scaffolds have gained interest due to their enhanced mechanical properties. However, these scaffolds are only osteoconductive and not osteoinductive. Stimulating regeneration of bone tissue, osteoinductivity, has therefore been a subject of intense research. We propose the use of carbon nanoparticle enhanced photoacoustic (PA) stimulation to promote and enhance tissue regeneration in bone tissue-engineering scaffolds. In this study we test the feasibility of using carbon nanoparticles and PA for in vivo tissue engineering applications. To this end, we investigate 1) the effect of carbon nanoparticles, such as graphene oxide nanoplatelets (GONP), graphene oxide nano ribbons (GONR) and graphene nano onions (GNO), in vitro on mesenchymal stem cells (MSC), which are crucial for bone regeneration; 2) the use of PA imaging to detect and monitor tissue engineering scaffolds in vivo; and 3) we demonstrate the potential of carbon nanoparticle enhanced PA stimulation to promote tissue regeneration and healing in an in vivo rat fracture model. The results from these studies demonstrate that carbon nanoparticles such as GNOP, GONR and GNO do not affect viability or differentiation of MSCs and could potentially be used in vivo for tissue engineering applications. Furthermore, PA imaging can be used to detect and longitudinally monitor subcutaneously implanted carbon nanotubes incorporated polymeric nanocomposites in vivo. Oxygen saturation data from PA imaging could also be used as an indicator for tissue regeneration within the scaffolds. Lastly, we demonstrate that daily stimulation with carbon nanoparticle enhanced PA increases bone fracture healing. Rats stimulated for 10 minutes daily for two weeks showed 3 times higher new cortical bone BV/TV and 1.8 times bone mineral density, compared to non-stimulated controls. The results taken together indicate that carbon nanoparticle enhanced PA stimulation serves as an anabolic stimulus for bone regeneration. The results suggest opportunities towards the development of implant device combination therapies for bone loss due to disease or trauma.

Redeployment of germ layers related TFs shows regionalized expression during two non-embryonic developments.

PubMed

Ricci, Lorenzo; Cabrera, Fabien; Lotito, Sonia; Tiozzo, Stefano

2016-08-01

In all non-vertebrate metazoan phyla, species that evolved non-embryonic developmental pathways as means of propagation or regeneration can be found. In this context, new bodies arise through asexual reproduction processes (such as budding) or whole body regeneration, that lack the familiar temporal and spatial cues classically associated with embryogenesis, like maternal determinants, or gastrulation. The molecular mechanisms underlying those non-embryonic developments (i.e., regeneration and asexual reproduction), and their relationship to those deployed during embryogenesis are poorly understood. We have addressed this question in the colonial ascidian Botryllus schlosseri, which undergoes an asexual reproductive process via palleal budding (PB), as well as a whole body regeneration by vascular budding (VB). We identified early regenerative structures during VB and then followed the fate of differentiating tissues during both non-embryonic developments (PB and VB) by monitoring the expression of genes known to play key functions in germ layer specification with well conserved expression patterns in solitary ascidian embryogenesis. The expression patterns of FoxA1, GATAa, GATAb, Otx, Bra, Gsc and Tbx2/3 were analysed during both PB and VB. We found that the majority of these transcription factors were expressed during both non-embryonic developmental processes, revealing a regionalization of the palleal and vascular buds. Knockdown of GATAa by siRNA in palleal buds confirmed that preventing the correct development of one of these regions blocks further tissue specification. Our results indicate that during both normal and injury-induced budding, a similar alternative developmental program operates via early commitment of epithelial regions. Copyright © 2016. Published by Elsevier Inc.

LYVE1 and PROX1 in the reconstruction of hepatic sinusoids after partial hepatectomy in mice.

PubMed

Meng, F

2017-01-01

Revascularisation is crucial to liver regeneration after liver injury, but the process remains unclear. This study investigated changes in the levels and distribution of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE1) and prospero homeobox protein 1 (PROX1) in liver tissue sections after partial hepatectomy in mice. Mice were subjected to partial hepatectomy. Control animals were sham-operated. From days 1 through 8, the remaining liver tissues were collected from 8 animals each day. Histology showed that after partial hepatectomy, the remaining liver tissue samples underwent initial degeneration and then hepatocyte proliferation and regeneration. Using immunohistochemical analysis, relative to the control a significantly higher number of vascular endothelial growth factor A (VEGFA)-positive hepatocytes was observed on days 4 and 5 after partial hepatectomy. LYVE1 was mainly present in the liver sinusoidal endothelial cells and the number of LYVE1-positive cells gradually increased with time. PROX1 was detected in some of the hepatocytes, but liver sinusoidal endothelial cells, artery, and vein were negative for PROX1 staining in the early stage after liver injury. The presence of PROX1 could be observed in some central veins as well as liver sinusoidal endothelial cells. Seven days after partial hepatectomy, colocalisation of PROX1 and LYVE1 was observed in liver sinusoidal endothelial cells and veins. This study revealed the dynamic process of revascularisation and hepatic sinusoid reconstruction during liver regeneration in response to liver injury in mice. PROX1 and LYVE1 may participate in this process and serve as biomarkers for identification of newly formed liver sinusoidal endothelial cells.

The zebrafish as a model for complex tissue regeneration

PubMed Central

Gemberling, Matthew; Bailey, Travis J.; Hyde, David R.; Poss, Kenneth D.

2013-01-01

For centuries, philosophers and scientists have been fascinated by the principles and implications of regeneration in lower vertebrate species. Two features have made zebrafish an informative model system for determining mechanisms of regenerative events. First, they are highly regenerative, able to regrow amputated fins, as well as a lesioned brain, retina, spinal cord, heart, and other tissues. Second, they are amenable to both forward and reverse genetic approaches, with a research toolset regularly updated by an expanding community of zebrafish researchers. Zebrafish studies have helped identify new mechanistic underpinnings of regeneration in multiple tissues, and in some cases have served as a guide for contemplating regenerative strategies in mammals. Here, we review the recent history of zebrafish as a genetic model system for understanding how and why tissue regeneration occurs. PMID:23927865

Guided bone regeneration using individualized ceramic sheets.

PubMed

Malmström, J; Anderud, J; Abrahamsson, P; Wälivaara, D-Å; Isaksson, S G; Adolfsson, E

2016-10-01

Guided bone regeneration (GBR) describes the use of membranes to regenerate bony defects. A membrane for GBR needs to be biocompatible, cell-occlusive, non-toxic, and mouldable, and possess space-maintaining properties including stability. The purpose of this pilot study was to describe a new method of GBR using individualized ceramic sheets to perfect bone regeneration prior to implant placement; bone regeneration was assessed using traditional histology and three-dimensional (3D) volumetric changes in the bone and soft tissue. Three patients were included. After full-thickness flap reflection, the individualized ceramic sheets were fixed. The sites were left to heal for 7 months. All patients were evaluated preoperatively and at 7 months postoperative using cone beam computed tomography and 3D optical equipment. Samples of the regenerated bone and soft tissue were collected and analyzed. The bone regenerated in the entire interior volume of all sheets. Bone biopsies revealed newly formed trabecular bone with a lamellar structure. Soft tissue biopsies showed connective tissue with no signs of an inflammatory response. This was considered to be newly formed periosteum. Thus ceramic individualized sheets can be used to regenerate large volumes of bone in both vertical and horizontal directions independent of the bone defect and with good biological acceptance of the material. Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

In vivo evaluation of hybrid patches composed of PLA based copolymers and collagen/chondroitin sulfate for ligament tissue regeneration.

PubMed

Pinese, Coline; Gagnieu, Christian; Nottelet, Benjamin; Rondot-Couzin, Capucine; Hunger, Sylvie; Coudane, Jean; Garric, Xavier

2017-10-01

Biomaterials for soft tissues regeneration should exhibit sufficient mechanical strength, demonstrating a mechanical behavior similar to natural tissues and should also promote tissues ingrowth. This study was aimed at developing new hybrid patches for ligament tissue regeneration by synergistic incorporation of a knitted structure of degradable polymer fibers to provide mechanical strength and of a biomimetic matrix to help injured tissues regeneration. PLA- Pluronic ® (PLA-P) and PLA-Tetronic ® (PLA-T) new copolymers were shaped as knitted patches and were associated with collagen I (Coll) and collagen I/chondroitine-sulfate (Coll CS) 3-dimensional matrices. In vitro study using ligamentocytes showed the beneficial effects of CS on ligamentocytes proliferation. Hybrid patches were then subcutaneously implanted in rats for 4 and 12 weeks. Despite degradation, patches retained strength to answer the mechanical physiological needs. Tissue integration capacity was assessed with histological studies. We showed that copolymers, associated with collagen and chondroitin sulfate sponge, exhibited very good tissue integration and allowed neotissue synthesis after 12 weeks in vivo. To conclude, PLA-P/CollCS and PLA-T/CollCS hybrid patches in terms of structure and composition give good hopes for tendon and ligament regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1778-1788, 2017. © 2016 Wiley Periodicals, Inc.

Efficacy of Honeycomb TCP-induced Microenvironment on Bone Tissue Regeneration in Craniofacial Area.

PubMed

Watanabe, Satoko; Takabatake, Kiyofumi; Tsujigiwa, Hidetsugu; Watanabe, Toshiyuki; Tokuyama, Eijiro; Ito, Satoshi; Nagatsuka, Hitoshi; Kimata, Yoshihiro

2016-01-01

Artificial bone materials that exhibit high biocompatibility have been developed and are being widely used for bone tissue regeneration. However, there are no biomaterials that are minimally invasive and safe. In a previous study, we succeeded in developing honeycomb β-tricalcium phosphate (β-TCP) which has through-and-through holes and is able to mimic the bone microenvironment for bone tissue regeneration. In the present study, we investigated how the difference in hole-diameter of honeycomb β-TCP (hole-diameter: 75, 300, 500, and 1600 μm) influences bone tissue regeneration histologically. Its osteoconductivity was also evaluated by implantation into zygomatic bone defects in rats. The results showed that the maximum bone formation was observed on the β-TCP with hole-diameter 300μm, included bone marrow-like tissue and the pattern of bone tissue formation similar to host bone. Therefore, the results indicated that we could control bone tissue formation by creating a bone microenvironment provided by β-TCP. Also, in zygomatic bone defect model with honeycomb β-TCP, the result showed there was osseous union and the continuity was reproduced between the both edges of resected bone and β-TCP, which indicated the zygomatic bone reproduction fully succeeded. It is thus thought that honeycomb β-TCP may serve as an excellent biomaterial for bone tissue regeneration in the head, neck and face regions, expected in clinical applications.

Efficacy of Honeycomb TCP-induced Microenvironment on Bone Tissue Regeneration in Craniofacial Area

PubMed Central

Watanabe, Satoko; Takabatake, Kiyofumi; Tsujigiwa, Hidetsugu; Watanabe, Toshiyuki; Tokuyama, Eijiro; Ito, Satoshi; Nagatsuka, Hitoshi; Kimata, Yoshihiro

2016-01-01

Artificial bone materials that exhibit high biocompatibility have been developed and are being widely used for bone tissue regeneration. However, there are no biomaterials that are minimally invasive and safe. In a previous study, we succeeded in developing honeycomb β-tricalcium phosphate (β-TCP) which has through-and-through holes and is able to mimic the bone microenvironment for bone tissue regeneration. In the present study, we investigated how the difference in hole-diameter of honeycomb β-TCP (hole-diameter: 75, 300, 500, and 1600 μm) influences bone tissue regeneration histologically. Its osteoconductivity was also evaluated by implantation into zygomatic bone defects in rats. The results showed that the maximum bone formation was observed on the β-TCP with hole-diameter 300μm, included bone marrow-like tissue and the pattern of bone tissue formation similar to host bone. Therefore, the results indicated that we could control bone tissue formation by creating a bone microenvironment provided by β-TCP. Also, in zygomatic bone defect model with honeycomb β-TCP, the result showed there was osseous union and the continuity was reproduced between the both edges of resected bone and β-TCP, which indicated the zygomatic bone reproduction fully succeeded. It is thus thought that honeycomb β-TCP may serve as an excellent biomaterial for bone tissue regeneration in the head, neck and face regions, expected in clinical applications. PMID:27279797

Molecular Signatures of Tissue-Specific Microvascular Endothelial Cell Heterogeneity in Organ Maintenance and Regeneration

PubMed Central

Nolan, Daniel J.; Ginsberg, Michael; Israely, Edo; Palikuqi, Brisa; Poulos, Michael G.; James, Daylon; Ding, Bi-Sen; Schachterle, William; Liu, Ying; Rosenwaks, Zev; Butler, Jason M.; Xiang, Jenny; Rafii, Arash; Shido, Koji; Rabbany, Sina Y.; Elemento, Olivier; Rafii, Shahin

2013-01-01

SUMMARY Microvascular endothelial cells (ECs) within different tissues are endowed with distinct but as yet unrecognized structural, phenotypic, and functional attributes. We devised EC purification, cultivation, profiling, and transplantation models that establish tissue-specific molecular libraries of ECs devoid of lymphatic ECs or parenchymal cells. These libraries identify attributes that confer ECs with their organotypic features. We show that clusters of transcription factors, angiocrine growth factors, adhesion molecules, and chemokines are expressed in unique combinations by ECs of each organ. Furthermore, ECs respond distinctly in tissue regeneration models, hepatectomy, and myeloablation. To test the data set, we developed a transplantation model that employs generic ECs differentiated from embryonic stem cells. Transplanted generic ECs engraft into regenerating tissues and acquire features of organotypic ECs. Collectively, we demonstrate the utility of informational databases of ECs toward uncovering the extravascular and intrinsic signals that define EC heterogeneity. These factors could be exploited therapeutically to engineer tissue-specific ECs for regeneration. PMID:23871589

Tissue regeneration during tissue expansion and choosing an expander

PubMed Central

Agrawal, K.; Agrawal, S.

2012-01-01

This paper reviews the various aspects of tissue regeneration during the process of tissue expansion. “Creep” and mechanical and biological “stretch” are responsible for expansion. During expansion, the epidermis thickens, the dermis thins out, vascularity improves, significant angiogenesis occurs, hair telogen phase becomes shorter and the peripheral nerves, vessels and muscle fibres lengthen. Expansion is associated with molecular changes in the tissue. Almost all these biological changes are reversible after the removal of the expander.This study is also aimed at reviewing the difficulty in deciding the volume and dimension of the expander for a defect. Basic mathematical formulae and the computer programmes for calculating the dimension of tissue expanders, although available in the literature, are not popular. A user-friendly computer programme based on the easily available Microsoft Excel spread sheet has been introduced. When we feed the area of defect and base dimension of the donor area or tissue expander, this programme calculates the volume and height of the expander. The shape of the expander is decided clinically based on the availability of the donor area and the designing of the future tissue movement. Today, tissue expansion is better understood biologically and mechanically. Clinical judgement remains indispensable in choosing the size and shape of the tissue expander. PMID:22754146

Fate of 3H-thymidine labelled myogenic cells in regeneration of muscle isografts.

PubMed

Gutmann, E; Mares, V; Stichová, J

1976-03-05

Intact and denervated extensor digitorum longus (EDL) muscles of 20-day-old inbred Lewis-Wistar rats were labelled with 3H-thymidine. Ninety minutes after the injection of the isotope 4.0% of the nuclei were labelled in the intact (i.e. innervated) and 9.6% in the muscles, denervated 3 days before administration of the isotope. The labelled EDL muscles were grafted into the bed of the previously removed EDL muscles of inbred animals and these isografts were studied 30 days later. In the EDL muscles, regenerated from innervated isografts only occasionally labelled endothelial cells were found whereas in the muscles regenerated from denervated isografts also parenchymal muscle nuclei were regularly labelled. The incidence of labelled nuclei in the regenerated EDL muscles was, however, about 20 times lower than in the donor EDL muscles. The presen experiments provide a direct proof of utilization of donor satelite cell nuclei for regeneration in grafted muscle tissue. With respect to the low incidence of labelled nuclei in regenerated EDL muscles, other sources of cells apparently also contribute to the regeneration process.

Concise Review: Biomimetic Functionalization of Biomaterials to Stimulate the Endogenous Healing Process of Cartilage and Bone Tissue

PubMed Central

Taraballi, Francesca; Bauza, Guillermo; McCulloch, Patrick; Harris, Josh

2017-01-01

Abstract Musculoskeletal reconstruction is an ongoing challenge for surgeons as it is required for one out of five patients undergoing surgery. In the past three decades, through the close collaboration between clinicians and basic scientists, several regenerative strategies have been proposed. These have emerged from interdisciplinary approaches that bridge tissue engineering with material science, physiology, and cell biology. The paradigm behind tissue engineering is to achieve regeneration and functional recovery using stem cells, bioactive molecules, or supporting materials. Although plenty of preclinical solutions for bone and cartilage have been presented, only a few platforms have been able to move from the bench to the bedside. In this review, we highlight the limitations of musculoskeletal regeneration and summarize the most relevant acellular tissue engineering approaches. We focus on the strategies that could be most effectively translate in clinical practice and reflect on contemporary and cutting‐edge regenerative strategies in surgery. Stem Cells Translational Medicine 2017;6:2186–2196 PMID:29080279

New approach in evaluation of ceramic-polymer composite bioactivity and biocompatibility.

PubMed

Borkowski, Leszek; Sroka-Bartnicka, Anna; Polkowska, Izabela; Pawlowska, Marta; Palka, Krzysztof; Zieba, Emil; Slosarczyk, Anna; Jozwiak, Krzysztof; Ginalska, Grazyna

2017-09-01

Regeneration of bone defects was promoted by a novel β-glucan/carbonate hydroxyapatite composite and characterized by Raman spectroscopy, microCT and electron microscopy. The elastic biomaterial with an apatite-forming ability was developed for bone tissue engineering and implanted into the critical-size defects of rabbits' tibiae. The bone repair process was analyzed on non-decalcified bone/implant sections during a 6-month regeneration period. Using spectroscopic methods, we were able to determine the presence of amides, lipids and assign the areas of newly formed bone tissue. Raman spectroscopy was also used to assess the chemical changes in the composite before and after the implantation process. SEM analyses showed the mineralization degree in the defect area and that the gap size decreased significantly. Microscopic images revealed that the implant debris were interconnected to the poorly mineralized inner side of a new bone tissue. Our study demonstrated that the composite may serve as a biocompatible background for collagen ingrowth and exhibits the advantages of applying Raman spectroscopy, SEM and microCT in studying these samples.

Stem Cells in Skin Regeneration, Wound Healing, and Their Clinical Applications

PubMed Central

Ojeh, Nkemcho; Pastar, Irena; Tomic-Canic, Marjana; Stojadinovic, Olivera

2015-01-01

The skin is the largest organ of the body and has an array of functions. Skin compartments, epidermis, and hair follicles house stem cells that are indispensable for skin homeostasis and regeneration. These stem cells also contribute to wound repair, resulting in restoration of tissue integrity and function of damaged tissue. Unsuccessful wound healing processes often lead to non-healing wounds. Chronic wounds are caused by depletion of stem cells and a variety of other cellular and molecular mechanisms, many of which are still poorly understood. Current chronic wound therapies are limited, so the search to develop better therapeutic strategies is ongoing. Adult stem cells are gaining recognition as potential candidates for numerous skin pathologies. In this review, we will discuss epidermal and other stem cells present in the skin, and highlight some of the therapeutic applications of epidermal stem cells and other adult stem cells as tools for cell/scaffold-based therapies for non-healing wounds and other skin disorders. We will also discuss emerging concepts and offer some perspectives on how skin tissue-engineered products can be optimized to provide efficacious therapy in cutaneous repair and regeneration. PMID:26512657

Stem Cells in Skin Regeneration, Wound Healing, and Their Clinical Applications.

PubMed

Ojeh, Nkemcho; Pastar, Irena; Tomic-Canic, Marjana; Stojadinovic, Olivera

2015-10-23

The skin is the largest organ of the body and has an array of functions. Skin compartments, epidermis, and hair follicles house stem cells that are indispensable for skin homeostasis and regeneration. These stem cells also contribute to wound repair, resulting in restoration of tissue integrity and function of damaged tissue. Unsuccessful wound healing processes often lead to non-healing wounds. Chronic wounds are caused by depletion of stem cells and a variety of other cellular and molecular mechanisms, many of which are still poorly understood. Current chronic wound therapies are limited, so the search to develop better therapeutic strategies is ongoing. Adult stem cells are gaining recognition as potential candidates for numerous skin pathologies. In this review, we will discuss epidermal and other stem cells present in the skin, and highlight some of the therapeutic applications of epidermal stem cells and other adult stem cells as tools for cell/scaffold-based therapies for non-healing wounds and other skin disorders. We will also discuss emerging concepts and offer some perspectives on how skin tissue-engineered products can be optimized to provide efficacious therapy in cutaneous repair and regeneration.

CtBP impedes JNK- and Upd/STAT-driven cell fate misspecifications in regenerating Drosophila imaginal discs

PubMed Central

Worley, Melanie I; Alexander, Larissa A

2018-01-01

Regeneration following tissue damage often necessitates a mechanism for cellular re-programming, so that surviving cells can give rise to all cell types originally found in the damaged tissue. This process, if unchecked, can also generate cell types that are inappropriate for a given location. We conducted a screen for genes that negatively regulate the frequency of notum-to-wing transformations following genetic ablation and regeneration of the wing pouch, from which we identified mutations in the transcriptional co-repressor C-terminal Binding Protein (CtBP). When CtBP function is reduced, ablation of the pouch can activate the JNK/AP-1 and JAK/STAT pathways in the notum to destabilize cell fates. Ectopic expression of Wingless and Dilp8 precede the formation of the ectopic pouch, which is subsequently generated by recruitment of both anterior and posterior cells near the compartment boundary. Thus, CtBP stabilizes cell fates following damage by opposing the destabilizing effects of the JNK/AP-1 and JAK/STAT pathways. PMID:29372681

An emerging cell-based strategy in orthopaedics: endothelial progenitor cells.

PubMed

Atesok, Kivanc; Matsumoto, Tomoyuki; Karlsson, Jon; Asahara, Takayuki; Atala, Anthony; Doral, M Nedim; Verdonk, Rene; Li, Ru; Schemitsch, Emil

2012-07-01

The purpose of this article was to analyze the results of studies in the literature, which evaluated the use of endothelial progenitor cells (EPCs) as a cell-based tissue engineering strategy. EPCs have been successfully used in regenerative medicine to augment neovascularization in patients after myocardial infarction and limb ischemia. EPCs' important role as vasculogenic progenitors presents them as a potential source for cell-based therapies to promote bone healing. EPCs have been shown to have prominent effects in promoting bone regeneration in several animal models. Evidence indicates that EPCs promote bone regeneration by stimulating both angiogenesis and osteogenesis through a differentiation process toward endothelial cell lineage and formation of osteoblasts. Moreover, EPCs increase vascularization and osteogenesis by increased secretion of growth factors and cytokines through paracrine mechanisms. EPCs offer the potential to emerge as a new strategy among other cell-based therapies to promote bone regeneration. Further investigations and human trials are required to address current questions with regard to biology and mechanisms of action of EPCs in bone tissue engineering.

Stem cell regenerative potential for plastic and reconstructive surgery.

PubMed

Boháč, Martin; Csöbönyeiová, Mária; Kupcová, Ida; Zamborský, Radoslav; Fedeleš, Jozef; Koller, Ján

2016-12-01

Stem cells represent heterogeneous population of undifferentiated cells with unique characteristics of long term self renewal and plasticity. Moreover, they are capable of active migration to diseased tissues, secretion of different bioactive molecules, and they have immunosuppressive potential as well. They occur in all tissues through life and are involved in process of embryogenesis and regeneration. During last decades stem cells attracted significant attention in each field of medicine, including plastic and reconstructive surgery. The main goal of the present review article is to present and discuss the potential of stem cells and to provide information about their safe utilization in chronic wounds and fistulae healing, scar management, breast reconstruction, as well as in bone, tendon and peripheral nerve regeneration.

Future Prospects for Scaffolding Methods and Biomaterials in Skin Tissue Engineering: A Review

PubMed Central

Chaudhari, Atul A.; Vig, Komal; Baganizi, Dieudonné Radé; Sahu, Rajnish; Dixit, Saurabh; Dennis, Vida; Singh, Shree Ram; Pillai, Shreekumar R.

2016-01-01

Over centuries, the field of regenerative skin tissue engineering has had several advancements to facilitate faster wound healing and thereby restoration of skin. Skin tissue regeneration is mainly based on the use of suitable scaffold matrices. There are several scaffold types, such as porous, fibrous, microsphere, hydrogel, composite and acellular, etc., with discrete advantages and disadvantages. These scaffolds are either made up of highly biocompatible natural biomaterials, such as collagen, chitosan, etc., or synthetic materials, such as polycaprolactone (PCL), and poly-ethylene-glycol (PEG), etc. Composite scaffolds, which are a combination of natural or synthetic biomaterials, are highly biocompatible with improved tensile strength for effective skin tissue regeneration. Appropriate knowledge of the properties, advantages and disadvantages of various biomaterials and scaffolds will accelerate the production of suitable scaffolds for skin tissue regeneration applications. At the same time, emphasis on some of the leading challenges in the field of skin tissue engineering, such as cell interaction with scaffolds, faster cellular proliferation/differentiation, and vascularization of engineered tissues, is inevitable. In this review, we discuss various types of scaffolding approaches and biomaterials used in the field of skin tissue engineering and more importantly their future prospects in skin tissue regeneration efforts. PMID:27898014

Future Prospects for Scaffolding Methods and Biomaterials in Skin Tissue Engineering: A Review.

PubMed

Chaudhari, Atul A; Vig, Komal; Baganizi, Dieudonné Radé; Sahu, Rajnish; Dixit, Saurabh; Dennis, Vida; Singh, Shree Ram; Pillai, Shreekumar R

2016-11-25

Over centuries, the field of regenerative skin tissue engineering has had several advancements to facilitate faster wound healing and thereby restoration of skin. Skin tissue regeneration is mainly based on the use of suitable scaffold matrices. There are several scaffold types, such as porous, fibrous, microsphere, hydrogel, composite and acellular, etc., with discrete advantages and disadvantages. These scaffolds are either made up of highly biocompatible natural biomaterials, such as collagen, chitosan, etc., or synthetic materials, such as polycaprolactone (PCL), and poly-ethylene-glycol (PEG), etc. Composite scaffolds, which are a combination of natural or synthetic biomaterials, are highly biocompatible with improved tensile strength for effective skin tissue regeneration. Appropriate knowledge of the properties, advantages and disadvantages of various biomaterials and scaffolds will accelerate the production of suitable scaffolds for skin tissue regeneration applications. At the same time, emphasis on some of the leading challenges in the field of skin tissue engineering, such as cell interaction with scaffolds, faster cellular proliferation/differentiation, and vascularization of engineered tissues, is inevitable. In this review, we discuss various types of scaffolding approaches and biomaterials used in the field of skin tissue engineering and more importantly their future prospects in skin tissue regeneration efforts.

Modeling Vascularized Bone Regeneration Within a Porous Biodegradable CaP Scaffold Loaded with Growth Factors

PubMed Central

Sun, X; Kang, Y; Bao, J; Zhang, Y; Yang, Y; Zhou, X

2013-01-01

Osteogenetic microenvironment is a complex constitution in which extracellular matrix (ECM) molecules, stem cells and growth factors each interact to direct the coordinate regulation of bone tissue development. Importantly, angiogenesis improvement and revascularization are critical for osteogenesis during bone tissue regeneration processes. In this study, we developed a three-dimensional (3D) multi-scale system model to study cell response to growth factors released from a 3D biodegradable porous calcium phosphate (CaP) scaffold. Our model reconstructed the 3D bone regeneration system and examined the effects of pore size and porosity on bone formation and angiogenesis. The results suggested that scaffold porosity played a more dominant role in affecting bone formation and angiogenesis compared with pore size, while the pore size could be controlled to tailor the growth factor release rate and release fraction. Furthermore, a combination of gradient VEGF with BMP2 and Wnt released from the multi-layer scaffold promoted angiogenesis and bone formation more readily than single growth factors. These results demonstrated that the developed model can be potentially applied to predict vascularized bone regeneration with specific scaffold and growth factors. PMID:23566802

Repair of osteochondral defects with in vitro engineered cartilage based on autologous bone marrow stromal cells in a swine model.

PubMed

He, Aijuan; Liu, Lina; Luo, Xusong; Liu, Yu; Liu, Yi; Liu, Fangjun; Wang, Xiaoyun; Zhang, Zhiyong; Zhang, Wenjie; Liu, Wei; Cao, Yilin; Zhou, Guangdong

2017-01-13

Functional reconstruction of large osteochondral defects is always a major challenge in articular surgery. Some studies have reported the feasibility of repairing articular osteochondral defects using bone marrow stromal cells (BMSCs) and biodegradable scaffolds. However, no significant breakthroughs have been achieved in clinical translation due to the instability of in vivo cartilage regeneration based on direct cell-scaffold construct implantation. To overcome the disadvantages of direct cell-scaffold construct implantation, the current study proposed an in vitro cartilage regeneration strategy, providing relatively mature cartilage-like tissue with superior mechanical properties. Our strategy involved in vitro cartilage engineering, repair of osteochondral defects, and evaluation of in vivo repair efficacy. The results demonstrated that BMSC engineered cartilage in vitro (BEC-vitro) presented a time-depended maturation process. The implantation of BEC-vitro alone could successfully realize tissue-specific repair of osteochondral defects with both cartilage and subchondral bone. Furthermore, the maturity level of BEC-vitro had significant influence on the repaired results. These results indicated that in vitro cartilage regeneration using BMSCs is a promising strategy for functional reconstruction of osteochondral defect, thus promoting the clinical translation of cartilage regeneration techniques incorporating BMSCs.

Mechanosensory organ regeneration in zebrafish depends on a population of multipotent progenitor cells kept latent by Schwann cells.

PubMed

Sánchez, Mario; Ceci, Maria Laura; Gutiérrez, Daniela; Anguita-Salinas, Consuelo; Allende, Miguel L

2016-04-07

Regenerating damaged tissue is a complex process, requiring progenitor cells that must be stimulated to undergo proliferation, differentiation and, often, migratory behaviors and morphological changes. Multiple cell types, both resident within the damaged tissue and recruited to the lesion site, have been shown to participate. However, the cellular and molecular mechanisms involved in the activation of progenitor cell proliferation and differentiation after injury, and their regulation by different cells types, are not fully understood. The zebrafish lateral line is a suitable system to study regeneration because most of its components are fully restored after damage. The posterior lateral line (PLL) is a mechanosensory system that develops embryonically and is initially composed of seven to eight neuromasts distributed along the trunk and tail, connected by a continuous stripe of interneuromastic cells (INCs). The INCs remain in a quiescent state owing to the presence of underlying Schwann cells. They become activated during development to form intercalary neuromasts. However, no studies have described if INCs can participate in a regenerative event, for example, after the total loss of a neuromast. We used electroablation in transgenic larvae expressing fluorescent proteins in PLL components to completely ablate single neuromasts in larvae and adult fish. This injury results in discontinuity of the INCs, Schwann cells, and the PLL nerve. In vivo imaging showed that the INCs fill the gap left after the injury and can regenerate a new neuromast in the injury zone. Further, a single INC is able to divide and form all cell types in a regenerated neuromast and, during this process, it transiently expresses the sox2 gene, a neural progenitor cell marker. We demonstrate a critical role for Schwann cells as negative regulators of INC proliferation and neuromast regeneration, and that this inhibitory property is completely dependent on active ErbB signaling. The potential to regenerate a neuromast after damage requires that progenitor cells (INCs) be temporarily released from an inhibitory signal produced by nearby Schwann cells. This simple yet highly effective two-component niche offers the animal robust mechanisms for organ growth and regeneration, which can be sustained throughout life.

Exosome-Like Vesicles Derived from Adipose Tissue Provide Biochemical Cues for Adipose Tissue Regeneration.

PubMed

Dai, Minjia; Yu, Mei; Zhang, Yan; Tian, Weidong

2017-11-01

There is an emerging need for soft tissue replacements in the field of reconstructive surgery for the treatment of congenital deformities, posttraumatic repair, and cancer rehabilitation. Previous studies have shown that the bioactive adipose tissue extract can induce adipogenesis without additional stem cells or growth factors. In this study, we innovatively investigated whether exosome-like vesicles derived from adipose tissue (ELV-AT) could direct stem cell differentiation and trigger adipose tissue regeneration. In vitro, ELV-AT can induce adipogenesis of adipose-derived stem cells and promote proliferation, migration, and angiogenic potential of the aorta endothelial cells. In vivo, ELV-AT were transplanted to a chamber on the back of nude mice and neoadipose tissues were formed. Our findings indicated that ELV-AT could be used as a cell-free therapeutic approach for adipose tissue regeneration.

Designing the stem cell microenvironment for guided connective tissue regeneration.

PubMed

Bogdanowicz, Danielle R; Lu, Helen H

2017-12-01

Adult mesenchymal stem cells (MSCs) are an attractive cell source for regenerative medicine because of their ability to self-renew and their capacity for multilineage differentiation and tissue regeneration. For connective tissues, such as ligaments or tendons, MSCs are vital to the modulation of the inflammatory response following acute injury while also interacting with resident fibroblasts to promote cell proliferation and matrix synthesis. To date, MSC injection for connective tissue repair has yielded mixed results in vivo, likely due to a lack of appropriate environmental cues to effectively control MSC response and promote tissue healing instead of scar formation. In healthy tissues, stem cells reside within a complex microenvironment comprising cellular, structural, and signaling cues that collectively maintain stemness and modulate tissue homeostasis. Changes to the microenvironment following injury regulate stem cell differentiation, trophic signaling, and tissue healing. Here, we focus on models of the stem cell microenvironment that are used to elucidate the mechanisms of stem cell regulation and inspire functional approaches to tissue regeneration. Recent studies in this frontier area are highlighted, focusing on how microenvironmental cues modulate MSC response following connective tissue injury and, more importantly, how this unique cell environment can be programmed for stem cell-guided tissue regeneration. © 2017 New York Academy of Sciences.

Laser-induced activation of regeneration processes in spine disc cartilage

NASA Astrophysics Data System (ADS)

Sobol, Emil N.; Vorobjeva, Natalia N.; Sviridov, Alexander P.; Omelchenko, Alexander I.; Baskov, Andrey V.; Shekhter, Anatoliy B.; Baskov, Vladimir A.; Feldchtein, Felix I.; Kamensky, Vladislav A.; Kuranov, Roman V.

2000-05-01

The effect of laser radiation on the regeneration processes in spine disk cartilage has been studied in-vivo. We used rabbits as a model and a Holmium (2.09 micrometer) and an Erbium fiber (1.56 micrometer) lasers for irradiation the discs which were preliminary opened to remove annulus fibrosus and the nucleus pulposus of the intervertebral disc. The irradiated zone has been examined using an optical coherent tomography in one month after the operation and conventional histological technique in two months after the laser operation. It has been shown that laser radiation promotes the growth of the new cartilaginous tissue of fibrous and hyaline types.

[Experimental-morphologic study of bone tissue reaction to carbon-containing material implantation with initiated X-ray contrast property].

PubMed

Grigorian, A S; Nabiev, F Kh; Golovin, R V

2005-01-01

In experimental study on 15 rabbits (chinchilla) influence of titanium plates implanted lapped on adjacent tissues in the region of the lower jaw body (comparison group) and carbon material with added boron in the concentrations of 8 and 15% (the study group) was studied. Results of the experimental-morphological investigation show that carbon-based materials with boron addition (with its content 8 and 15%) did not impede adaptive rebuilding of bone tissues and in particular bone structure regeneration in the process of reactive rebuilding of the "maternal" bone. Moreover, as the result of reactive processes developing in osseous tissues after implantation of the tested materials their successful integration in surrounding tissue structures was detected.

Generation and Assessment of Functional Biomaterial Scaffolds for Applications in Cardiovascular Tissue Engineering and Regenerative Medicine

PubMed Central

Hinderer, Svenja; Brauchle, Eva

2015-01-01

Current clinically applicable tissue and organ replacement therapies are limited in the field of cardiovascular regenerative medicine. The available options do not regenerate damaged tissues and organs, and, in the majority of the cases, show insufficient restoration of tissue function. To date, anticoagulant drug‐free heart valve replacements or growing valves for pediatric patients, hemocompatible and thrombus‐free vascular substitutes that are smaller than 6 mm, and stem cell‐recruiting delivery systems that induce myocardial regeneration are still only visions of researchers and medical professionals worldwide and far from being the standard of clinical treatment. The design of functional off‐the‐shelf biomaterials as well as automatable and up‐scalable biomaterial processing methods are the focus of current research endeavors and of great interest for fields of tissue engineering and regenerative medicine. Here, various approaches that aim to overcome the current limitations are reviewed, focusing on biomaterials design and generation methods for myocardium, heart valves, and blood vessels. Furthermore, novel contact‐ and marker‐free biomaterial and extracellular matrix assessment methods are highlighted. PMID:25778713

Emerging Roles for Extracellular Vesicles in Tissue Engineering and Regenerative Medicine

PubMed Central

Lamichhane, Tek N.; Sokic, Sonja; Schardt, John S.; Raiker, Rahul S.; Lin, Jennifer W.

2015-01-01

Extracellular vesicles (EVs)—comprising a heterogeneous population of cell-derived lipid vesicles including exosomes, microvesicles, and others—have recently emerged as both mediators of intercellular information transfer in numerous biological systems and vehicles for drug delivery. In both roles, EVs have immense potential to impact tissue engineering and regenerative medicine applications. For example, the therapeutic effects of several progenitor and stem cell-based therapies have been attributed primarily to EVs secreted by these cells, and EVs have been recently reported to play direct roles in injury-induced tissue regeneration processes in multiple physiological systems. In addition, EVs have been utilized for targeted drug delivery in regenerative applications and possess unique potential to be harnessed as patient-derived drug delivery vehicles for personalized medicine. This review discusses EVs in the context of tissue repair and regeneration, including their utilization as drug carriers and their crucial role in cell-based therapies. Furthermore, the article highlights the growing need for bioengineers to understand, consider, and ultimately design and specifically control the activity of EVs to maximize the efficacy of tissue engineering and regenerative therapies. PMID:24957510

Next Generation Tissue Engineering of Orthopedic Soft Tissue-to-Bone Interfaces.

PubMed

Boys, Alexander J; McCorry, Mary Clare; Rodeo, Scott; Bonassar, Lawrence J; Estroff, Lara A

2017-09-01

Soft tissue-to-bone interfaces are complex structures that consist of gradients of extracellular matrix materials, cell phenotypes, and biochemical signals. These interfaces, called entheses for ligaments, tendons, and the meniscus, are crucial to joint function, transferring mechanical loads and stabilizing orthopedic joints. When injuries occur to connected soft tissue, the enthesis must be re-established to restore function, but due to structural complexity, repair has proven challenging. Tissue engineering offers a promising solution for regenerating these tissues. This prospective review discusses methodologies for tissue engineering the enthesis, outlined in three key design inputs: materials processing methods, cellular contributions, and biochemical factors.

Next Generation Tissue Engineering of Orthopedic Soft Tissue-to-Bone Interfaces

PubMed Central

Boys, Alexander J.; McCorry, Mary Clare; Rodeo, Scott; Bonassar, Lawrence J.; Estroff, Lara A.

2017-01-01

Soft tissue-to-bone interfaces are complex structures that consist of gradients of extracellular matrix materials, cell phenotypes, and biochemical signals. These interfaces, called entheses for ligaments, tendons, and the meniscus, are crucial to joint function, transferring mechanical loads and stabilizing orthopedic joints. When injuries occur to connected soft tissue, the enthesis must be re-established to restore function, but due to structural complexity, repair has proven challenging. Tissue engineering offers a promising solution for regenerating these tissues. This prospective review discusses methodologies for tissue engineering the enthesis, outlined in three key design inputs: materials processing methods, cellular contributions, and biochemical factors. PMID:29333332

Nanobiotechnology and bone regeneration: a mini-review.

PubMed

Gusić, Nadomir; Ivković, Alan; VaFaye, John; Vukasović, Andreja; Ivković, Jana; Hudetz, Damir; Janković, Saša

2014-09-01

The purpose of this paper is to review current developments in bone tissue engineering, with special focus on the promising role of nanobiotechnology. This unique fusion between nanotechnology and biotechnology offers unprecedented possibilities in studying and modulating biological processes on a molecular and atomic scale. First we discuss the multiscale hierarchical structure of bone and its implication on the design of new scaffolds and delivery systems. Then we briefly present different types of nanostructured scaffolds, and finally we conclude with nanoparticle delivery systems and their potential use in promoting bone regeneration. This review is not meant to be exhaustive and comprehensive, but aims to highlight concepts and key advances in the field of nanobiotechnology and bone regeneration.

De Novo Kidney Regeneration with Stem Cells

PubMed Central

Yokote, Shinya; Yamanaka, Shuichiro; Yokoo, Takashi

2012-01-01

Recent studies have reported on techniques to mobilize and activate endogenous stem-cells in injured kidneys or to introduce exogenous stem cells for tissue repair. Despite many recent advantages in renal regenerative therapy, chronic kidney disease (CKD) remains a major cause of morbidity and mortality and the number of CKD patients has been increasing. When the sophisticated structure of the kidneys is totally disrupted by end stage renal disease (ESRD), traditional stem cell-based therapy is unable to completely regenerate the damaged tissue. This suggests that whole organ regeneration may be a promising therapeutic approach to alleviate patients with uncured CKD. We summarize here the potential of stem-cell-based therapy for injured tissue repair and de novo whole kidney regeneration. In addition, we describe the hurdles that must be overcome and possible applications of this approach in kidney regeneration. PMID:23251079

Pseudotyped baculovirus is an effective gene expression tool for studying molecular function during axolotl limb regeneration.

PubMed

Oliveira, Catarina R; Lemaitre, Regis; Murawala, Prayag; Tazaki, Akira; Drechsel, David N; Tanaka, Elly M

2018-01-15

Axolotls can regenerate complex structures through recruitment and remodeling of cells within mature tissues. Accessing the underlying mechanisms at a molecular resolution is crucial to understand how injury triggers regeneration and how it proceeds. However, gene transformation in adult tissues can be challenging. Here we characterize the use of pseudotyped baculovirus (BV) as an effective gene transfer method both for cells within mature limb tissue and within the blastema. These cells remain competent to participate in regeneration after transduction. We further characterize the effectiveness of BV for gene overexpression studies by overexpressing Shh in the blastema, which yields a high penetrance of classic polydactyly phenotypes. Overall, our work establishes BV as a powerful tool to access gene function in axolotl limb regeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

Heterogeneous fates and dynamic rearrangement of regenerative epidermis-derived cells during zebrafish fin regeneration.

PubMed

Shibata, Eri; Ando, Kazunori; Murase, Emiko; Kawakami, Atsushi

2018-04-13

The regenerative epidermis (RE) is a specialized tissue that plays an essential role in tissue regeneration. However, the fate of the RE during and after regeneration is unknown. In this study, we performed Cre- loxP -mediated cell fate tracking and revealed the fates of a major population of the RE cells that express fibronectin 1b ( fn1b ) during zebrafish fin regeneration. Our study showed that these RE cells are mainly recruited from the inter-ray epidermis, and that they follow heterogeneous cell fates. Early recruited cells contribute to initial wound healing and soon disappear by apoptosis, while the later recruited cells contribute to the regenerated epidermis. Intriguingly, many of these cells are also expelled from the regenerated tissue by a dynamic caudal movement of the epidermis over time, and in turn the loss of epidermal cells is replenished by a global self-replication of basal and suprabasal cells in fin. De-differentiation of non-basal epidermal cells into the basal epidermal cells did not occur during regeneration. Overall, our study reveals the heterogeneous fates of RE cells and a dynamic rearrangement of the epidermis during and after regeneration. © 2018. Published by The Company of Biologists Ltd.

[Evaluation of Cepan Cream after 15 years of treatment of burn scars].

PubMed

Stozkowska, Wiesława

2002-01-01

Cepan Cream is used for the topical treatment of scars and keloids resulting from burns, post-operative scars, and contractures. Cepan Cream makes scars more elastic, softer and paler. Plant extracts, heparin and allantoin in Cepan act on the biochemical processes in the developing connective tissue, preventing the formation of hyperplastic scars. These active ingredients enhance swelling, softening and loosening of connective tissue. It exerts softening and smoothing action on indurated and hyperplastic scar tissue, improving collagen structure. It promotes tissue regeneration and reduces exuberant granulation. Cepan is well tolerated.

Potential for Stem Cell-Based Periodontal Therapy

PubMed Central

Bassir, Seyed Hossein; Wisitrasameewong, Wichaya; Raanan, Justin; Ghaffarigarakani, Sasan; Chung, Jamie; Freire, Marcelo; Andrada, Luciano C.; Intini, Giuseppe

2015-01-01

Periodontal diseases are highly prevalent and are linked to several systemic diseases. The goal of periodontal treatment is to halt the progression of the disease and regenerate the damaged tissue. However, achieving complete and functional periodontal regeneration is challenging because the periodontium is a complex apparatus composed of different tissues, including bone, cementum, and periodontal ligament. Stem cell-based regenerative therapy may represent an effective therapeutic tool for periodontal regeneration due to their plasticity and ability to differentiate into different cell lineages. This review presents and critically analyzes the available information on stem cell-based therapy for the regeneration of periodontal tissues and suggests new avenues for the development of more effective therapeutic protocols. PMID:26058394

How does tissue regeneration influence the mechanical behavior of additively manufactured porous biomaterials?

PubMed

Hedayati, R; Janbaz, S; Sadighi, M; Mohammadi-Aghdam, M; Zadpoor, A A

2017-01-01

Although the initial mechanical properties of additively manufactured porous biomaterials are intensively studied during the last few years, almost no information is available regarding the evolution of the mechanical properties of implant-bone complex as the tissue regeneration progresses. In this paper, we studied the effects of tissue regeneration on the static and fatigue behavior of selective laser melted porous titanium structures with three different porosities (i.e. 77, 81, and 85%). The porous structures were filled with four different polymeric materials with mechanical properties in the range of those observed for de novo bone (0.7GPa

Factors promoting increased rate of tissue regeneration: the zebrafish fin as a tool for examining tissue engineering design concepts.

PubMed

Boominathan, Vijay P; Ferreira, Tracie L

2012-12-01

Student interest in topics of tissue engineering is increasing exponentially as the number of universities offering programs in bioengineering are on the rise. Bioengineering encompasses all of the STEM categories: Science, Technology, Engineering, and Math. Inquiry-based learning is one of the most effective techniques for promoting student learning and has been demonstrated to have a high impact on learning outcomes. We have designed program outcomes for our bioengineering program that require tiered activities to develop problem solving skills, peer evaluation techniques, and promote team work. While it is ideal to allow students to ask unique questions and design their own experiments, this can be difficult for instructors to have reagents and supplies available for a variety of activities. Zebrafish can be easily housed, and multiple variables can be tested on a large enough group to provide statistical value, lending them well to inquiry-based learning modules. We have designed a laboratory activity that takes observation of fin regeneration to the next level: analyzing conditions that may impact regeneration. Tissue engineers seek to define the optimum conditions to grow tissue for replacement parts. The field of tissue engineering is likely to benefit from understanding natural mechanisms of regeneration and the factors that influence the rate of regeneration. We have outlined the results of varying temperature on fin regeneration and propose other inquiry modules such as the role of pH in fin regeneration. Furthermore, we have provided useful tools for developing critical thinking and peer review of research ideas, assessment guidelines, and grading rubrics for the activities associated with this exercise.

JNK Controls the Onset of Mitosis in Planarian Stem Cells and Triggers Apoptotic Cell Death Required for Regeneration and Remodeling

PubMed Central

Almuedo-Castillo, María; Crespo, Xenia; Seebeck, Florian; Bartscherer, Kerstin; Salò, Emili; Adell, Teresa

2014-01-01

Regeneration of lost tissues depends on the precise interpretation of molecular signals that control and coordinate the onset of proliferation, cellular differentiation and cell death. However, the nature of those molecular signals and the mechanisms that integrate the cellular responses remain largely unknown. The planarian flatworm is a unique model in which regeneration and tissue renewal can be comprehensively studied in vivo. The presence of a population of adult pluripotent stem cells combined with the ability to decode signaling after wounding enable planarians to regenerate a complete, correctly proportioned animal within a few days after any kind of amputation, and to adapt their size to nutritional changes without compromising functionality. Here, we demonstrate that the stress-activated c-jun–NH2–kinase (JNK) links wound-induced apoptosis to the stem cell response during planarian regeneration. We show that JNK modulates the expression of wound-related genes, triggers apoptosis and attenuates the onset of mitosis in stem cells specifically after tissue loss. Furthermore, in pre-existing body regions, JNK activity is required to establish a positive balance between cell death and stem cell proliferation to enable tissue renewal, remodeling and the maintenance of proportionality. During homeostatic degrowth, JNK RNAi blocks apoptosis, resulting in impaired organ remodeling and rescaling. Our findings indicate that JNK-dependent apoptotic cell death is crucial to coordinate tissue renewal and remodeling required to regenerate and to maintain a correctly proportioned animal. Hence, JNK might act as a hub, translating wound signals into apoptotic cell death, controlled stem cell proliferation and differentiation, all of which are required to coordinate regeneration and tissue renewal. PMID:24922054

Macrophages and fibroblasts during inflammation and tissue repair in models of organ regeneration

PubMed Central

2017-01-01

Abstract This review provides a concise summary of the changing phenotypes of macrophages and fibroblastic cells during the local inflammatory response, the onset of tissue repair, and the resolution of inflammation which follow injury to an organ. Both cell populations respond directly to damage and present coordinated sequences of activation states which determine the reparative outcome, ranging from true regeneration of the organ to fibrosis and variable functional deficits. Recent work with mammalian models of organ regeneration, including regeneration of full‐thickness skin, hair follicles, ear punch tissues, and digit tips, is summarized and the roles of local immune cells in these systems are discussed. New investigations of the early phase of amphibian limb and tail regeneration, including the effects of pro‐inflammatory and anti‐inflammatory agents, are then briefly discussed, focusing on the transition from the normally covert inflammatory response to the initiation of the regeneration blastema by migrating fibroblasts and the expression of genes for limb patterning. PMID:28616244

Concise Review: Tissue-Engineered Skin and Nerve Regeneration in Burn Treatment

PubMed Central

Blais, Mathieu; Parenteau-Bareil, Rémi; Cadau, Sébastien

2013-01-01

Burns not only destroy the barrier function of the skin but also alter the perceptions of pain, temperature, and touch. Different strategies have been developed over the years to cover deep and extensive burns with the ultimate goal of regenerating the barrier function of the epidermis while recovering an acceptable aesthetic aspect. However, patients often complain about a loss of skin sensation and even cutaneous chronic pain. Cutaneous nerve regeneration can occur from the nerve endings of the wound bed, but it is often compromised by scar formation or anarchic wound healing. Restoration of pain, temperature, and touch perceptions should now be a major challenge to solve in order to improve patients' quality of life. In addition, the cutaneous nerve network has been recently highlighted to play an important role in epidermal homeostasis and may be essential at least in the early phase of wound healing through the induction of neurogenic inflammation. Although the nerve regeneration process was studied largely in the context of nerve transections, very few studies have been aimed at developing strategies to improve it in the context of cutaneous wound healing. In this concise review, we provide a description of the characteristics of and current treatments for extensive burns, including tissue-engineered skin approaches to improve cutaneous nerve regeneration, and describe prospective uses for autologous skin-derived adult stem cells to enhance recovery of the skin's sense of touch. PMID:23734060

Allogeneic stem cells from deciduous teeth in treatment for periodontitis in miniature swine.

PubMed

Fu, Xiaoru; Jin, Luyuan; Ma, Ping; Fan, Zhipeng; Wang, Songlin

2014-06-01

Regeneration of lost periodontium in periodontitis is a challenge in that alveolar bone, cementum, and periodontal ligament need to be restored to their original architecture. Stem cells from exfoliated deciduous teeth (SHEDs) appear to be an attractive candidate for periodontium tissue regeneration. Previously, the authors successfully regenerated periodontal defects using autologous and allogeneic periodontal ligament stem cells (PDLSCs). The purpose of the present study is to investigate the ability of allogeneic SHEDs to regenerate lost periodontium in a swine periodontitis model. Animal models of periodontitis were established in miniature pigs, and allogeneic stem cells were isolated from miniature pig deciduous teeth (SPDs). The animal models were treated with SPDs plus hydroxyapatite/tricalcium phosphate (HA/TCP). Allogeneic PDLSCs plus HA/TCP or HA/TCP alone were set as positive control or control, respectively. Clinical assessments, computed tomography (CT) scanning, and histologic examination were used to evaluate the outcome of tissue regeneration. Clinical indices including probing depth, gingival recession, and attachment loss showed significant restoration in the SPD and PDLSC treatment groups, compared to the HA/TCP group 12 weeks post-transplantation. Meanwhile, CT scans showed that 75% of the samples had successful hard-tissue regeneration in both PDLSC and SPD groups, compared to the HA/TCP group, where the success rate was only 25%. In addition, histologic examination demonstrated that SPD and PDLSC treatment brought about remarkable regeneration of periodontal tissues, whereas periodontal regeneration was rare in the HA/TCP group. Allogeneic SPDs can effectively repair hard and soft tissue loss brought about by periodontitis in a swine model. Allogeneic SHEDs, which are easily accessible, may be applied to treat periodontitis in clinics in the future.

In vivo differentiation of human periodontal ligament cells leads to formation of dental hard tissue.

PubMed

Wolf, M; Lossdörfer, S; Abuduwali, N; Meyer, R; Kebir, S; Götz, W; Jäger, A

2013-11-01

Following trauma, periodontal disease, or orthodontic tooth movement, residual periodontal ligament (PDL) cells at the defect site are considered mandatory for successful regeneration of the injured structures. Recent developments in tissue engineering focus, as one pillar, on the transplantation of PDL cells to support periodontal regeneration processes. Here, we examined the ability of osteogenically predifferentiated PDL cells to undergo further osteoblastic or cementoblastic differentiation and to mineralize their extracellular matrix when transplanted in an in vivo microenvironment. Using collagen sponges as carriers, osteogenically predifferentiated human PDL cells were transplanted subcutaneously into six immunocompromised CD-1® nude mice. Following explantation after 28 days, osteogenic and cementogenic marker protein expression was visualized immunohistochemically. After 28 days, transplanted PDL cells revealed both cellular, cytoplasmatic and extracellular immunoreactivity for the chosen markers alkaline phosphatase, osteopontin, PTH-receptor 1, and osteocalcin. Specific osteogenic and cementoblastic differentiation was demonstrated by RUNX2 and CEMP1 immunoreactivity. Early stages of mineralization were demonstrated by calcium and phosphate staining. Our results reinforce the previously published reports of PDL cell mineralization in vivo and further demonstrate the successful induction of specific osteogenic and cementogenic differentiation of transplanted human PDL cells in vivo. These findings reveal promising possibilities for supporting periodontal remodeling and regeneration processes with PDL cells being potential target cells with which to influence the process of orthodontically induced root resorption.

Nanofibers based tissue engineering and drug delivery approaches for myocardial regeneration.

PubMed

Joshi, Jyotsna; Kothapalli, Chandrasekhar R

2015-01-01

Human heart has endogenous regenerative capability; however, the intrinsic repair mechanism is not sufficient to overcome the impact placed by adverse pathological conditions, such as myocardial infarction (MI). In such circumstances, the damaged tissue initiates a series of remodeling process which results in the deterioration of structural, functional, and mechanical properties of the myocardium. To address such adverse conditions, clinical approaches ranging from surgical interventions, pharmaceutical drugs, and device implantation are administered which have played significant role in reducing the mortality rate. However, these approaches do not replace the lost cardiomyocytes, or restore the degraded structure-function relationship of the myocardium. In this aspect, cell-based therapy has gained substantial interest as a potential clinical approach for myocardial regeneration; however this method is impeded by lower graft retention and poor cell viability. To overcome these limitations, biomaterials are being developed as "trojan horses", i.e., vehicles for homing and deploying cells, and as matrices for delivering specific biological, mechanical, and chemical cues intended for tissue regeneration. Similarly, several candidate drugs, potent synthetic and biological molecules, and advanced drug delivery systems are being examined to provide exogenous cues in a controlled fashion to the diseased myocardium. In this article, we review biomaterials-based drug delivery systems for myocardial regeneration, specifically on the applications of hydrogels, microgels, nanoparticles, and nanofibers in the field. The prime focus of the article is on nanofibers-based drug delivery systems that is gaining considerable attention as a biomimetic pharmacological approach. We highlight literature on fabrication methods of self-assembling and electrospun nanofibers, drug incorporation methods and release kinetics, and in vitro and in vivo outcomes from nanofiber-based drug delivery systems in cardiac regeneration.

Action Mechanism of Fibroblast Growth Factor-2 (FGF-2) in the Promotion of Periodontal Regeneration in Beagle Dogs

PubMed Central

Nagayasu-Tanaka, Toshie; Anzai, Jun; Takaki, Shu; Shiraishi, Noriko; Terashima, Akio; Asano, Taiji; Nozaki, Takenori; Kitamura, Masahiro; Murakami, Shinya

2015-01-01

Fibroblast growth factor-2 (FGF-2) enhances the formation of new alveolar bone, cementum, and periodontal ligament (PDL) in periodontal defect models. However, the mechanism through which FGF-2 acts in periodontal regeneration in vivo has not been fully clarified yet. To reveal the action mechanism, the formation of regenerated tissue and gene expression at the early phase were analyzed in a beagle dog 3-wall periodontal defect model. FGF-2 (0.3%) or the vehicle (hydroxypropyl cellulose) only were topically applied to the defect in FGF-2 and control groups, respectively. Then, the amount of regenerated tissues and the number of proliferating cells at 3, 7, 14, and 28 days and the number of blood vessels at 7 days were quantitated histologically. Additionally, the expression of osteogenic genes in the regenerated tissue was evaluated by real-time PCR at 7 and 14 days. Compared with the control, cell proliferation around the existing bone and PDL, connective tissue formation on the root surface, and new bone formation in the defect at 7 days were significantly promoted by FGF-2. Additionally, the number of blood vessels at 7 days was increased by FGF-2 treatment. At 28 days, new cementum and PDL were extended by FGF-2. Moreover, FGF-2 increased the expression of bone morphogenetic protein 2 (BMP-2) and osteoblast differentiation markers (osterix, alkaline phosphatase, and osteocalcin) in the regenerated tissue. We revealed the facilitatory mechanisms of FGF-2 in periodontal regeneration in vivo. First, the proliferation of fibroblastic cells derived from bone marrow and PDL was accelerated and enhanced by FGF-2. Second, angiogenesis was enhanced by FGF-2 treatment. Finally, osteoblastic differentiation and bone formation, at least in part due to BMP-2 production, were rapidly induced by FGF-2. Therefore, these multifaceted effects of FGF-2 promote new tissue formation at the early regeneration phase, leading to enhanced formation of new bone, cementum, and PDL. PMID:26120833

Activation of germline-specific genes is required for limb regeneration in the Mexican axolotl

PubMed Central

Zhu, Wei; Pao, Gerald M; Satoh, Akira; Cummings, Gillian; Monaghan, James R; Harkins, Timothy T; Bryant, Susan V; Voss, S Randal; Gardiner, David M; Hunter, Tony

2013-01-01

The capacity for tissue and organ regeneration in humans is dwarfed by comparison to that of salamanders. Emerging evidence suggests that mechanisms learned from the early phase of salamander limb regeneration – wound healing, cellular dedifferentiation and blastemal formation – will reveal therapeutic approaches for tissue regeneration in humans. Here we describe a unique transcriptional fingerprint of regenerating limb tissue in the Mexican axolotl (Ambystoma mexicanum) that is indicative of cellular reprogramming of differentiated cells to a germline-like state. Two genes that are required for self-renewal of germ cells in mice and flies, Piwi-like 1 (PL1) and Piwi-like 2 (PL2), are expressed in limb blastemal cells, the basal layer keratinocytes and the thickened apical epithelial cap in the wound epidermis in the regenerating limb. Depletion of PL1 and PL2 by morpholino oligonucleotides decreased cell proliferation and increased cell death in the blastema leading to a significant retardation of regeneration. Examination of key molecules that are known to be required for limb development or regeneration further revealed that FGF8 is transcriptionally downregulated in the presence of the morpholino oligos, indicating PL1 and PL2 might participate in FGF signaling during limb regeneration. Given the requirement for FGF signaling in limb development and regeneration, the results suggest that PL1 and PL2 function to establish a unique germline-like state that is associated with successful regeneration. PMID:22841627

Dynamic Mechanical and Nanofibrous Topological Combinatory Cues Designed for Periodontal Ligament Engineering.

PubMed

Kim, Joong-Hyun; Kang, Min Sil; Eltohamy, Mohamed; Kim, Tae-Hyun; Kim, Hae-Won

2016-01-01

Complete reconstruction of damaged periodontal pockets, particularly regeneration of periodontal ligament (PDL) has been a significant challenge in dentistry. Tissue engineering approach utilizing PDL stem cells and scaffolding matrices offers great opportunity to this, and applying physical and mechanical cues mimicking native tissue conditions are of special importance. Here we approach to regenerate periodontal tissues by engineering PDL cells supported on a nanofibrous scaffold under a mechanical-stressed condition. PDL stem cells isolated from rats were seeded on an electrospun polycaprolactone/gelatin directionally-oriented nanofiber membrane and dynamic mechanical stress was applied to the cell/nanofiber construct, providing nanotopological and mechanical combined cues. Cells recognized the nanofiber orientation, aligning in parallel, and the mechanical stress increased the cell alignment. Importantly, the cells cultured on the oriented nanofiber combined with the mechanical stress produced significantly stimulated PDL specific markers, including periostin and tenascin with simultaneous down-regulation of osteogenesis, demonstrating the roles of topological and mechanical cues in altering phenotypic change in PDL cells. Tissue compatibility of the tissue-engineered constructs was confirmed in rat subcutaneous sites. Furthermore, in vivo regeneration of PDL and alveolar bone tissues was examined under the rat premaxillary periodontal defect models. The cell/nanofiber constructs engineered under mechanical stress showed sound integration into tissue defects and the regenerated bone volume and area were significantly improved. This study provides an effective tissue engineering approach for periodontal regeneration-culturing PDL stem cells with combinatory cues of oriented nanotopology and dynamic mechanical stretch.

Satellite Cells and the Muscle Stem Cell Niche

PubMed Central

Yin, Hang; Price, Feodor

2013-01-01

Adult skeletal muscle in mammals is a stable tissue under normal circumstances but has remarkable ability to repair after injury. Skeletal muscle regeneration is a highly orchestrated process involving the activation of various cellular and molecular responses. As skeletal muscle stem cells, satellite cells play an indispensible role in this process. The self-renewing proliferation of satellite cells not only maintains the stem cell population but also provides numerous myogenic cells, which proliferate, differentiate, fuse, and lead to new myofiber formation and reconstitution of a functional contractile apparatus. The complex behavior of satellite cells during skeletal muscle regeneration is tightly regulated through the dynamic interplay between intrinsic factors within satellite cells and extrinsic factors constituting the muscle stem cell niche/microenvironment. For the last half century, the advance of molecular biology, cell biology, and genetics has greatly improved our understanding of skeletal muscle biology. Here, we review some recent advances, with focuses on functions of satellite cells and their niche during the process of skeletal muscle regeneration. PMID:23303905

Skin regeneration in deep second-degree scald injuries either by infusion pumping or topical application of recombinant human erythropoietin gel.

PubMed

Giri, Priya; Ebert, Sabine; Braumann, Ulf-Dietrich; Kremer, Mathias; Giri, Shibashish; Machens, Hans-Günther; Bader, Augustinus

2015-01-01

Large doses of recombinant growth factors formulated in solution form directly injected into the body is usual clinical practice in treating second-degree scald injuries, with promising results, but this approach creates side effects; furthermore, it may not allow appropriate levels of the factor to be sensed by the target injured tissue/organ in the specific time frame, owing to complications arising from regeneration. In this research, two delivery methods (infusion pumping and local topical application) were applied to deliver recombinant human erythropoietin (rHuEPO) for skin regeneration. First, rHuEPO was given in deep second-degree scald injury sites in mice by infusion pump. Vascularization was remarkably higher in the rHuEPO pumping group than in controls. Second, local topical application of rHuEPO gel was given in deep second-degree scald injury sites in rats. Histological analysis showed that epithelialization rate was significantly higher in the rHuEPO gel-treated group than in controls. Immunohistochemical studies showed that the rHuEPO gel-treated group showed remarkably higher expression of skin regeneration makers than the control group. An accurate method for visualization and quantification of blood vessel networks in target areas has still not been developed up to this point, because of technical difficulties in detecting such thin blood vessels. A method which utilizes a series of steps to enhance the image, removes noise from image background, and tracks the vessels edges for vessel segmentation and quantification has been used in this study. Using image analysis methods, we were able to detect the microvascular networks of newly formed blood vessels (less than 500 μm thickness), which participate in the healing process, providing not only nutrition and oxygen to grow tissues but also necessary growth factors to grow tissue cells for complete skin regeneration. The rHuEPO-treated group showed higher expression of stem cell markers (CD 31, CD 90, CD 71, and nestin), which actively contribute to in-wound-healing processes for new hair follicle generation as well as skin regeneration. Collectively, both rHuEPO group pumping into the systemic circulation system, and injection into the local injury area, prompted mice and rats to form new blood vessel networks in scald injury sites, which significantly participate in the scald healing process. These results may lead to the development of novel treatments for scald wounds.

Skin regeneration in deep second-degree scald injuries either by infusion pumping or topical application of recombinant human erythropoietin gel

PubMed Central

Giri, Priya; Ebert, Sabine; Braumann, Ulf-Dietrich; Kremer, Mathias; Giri, Shibashish; Machens, Hans-Günther; Bader, Augustinus

2015-01-01

Large doses of recombinant growth factors formulated in solution form directly injected into the body is usual clinical practice in treating second-degree scald injuries, with promising results, but this approach creates side effects; furthermore, it may not allow appropriate levels of the factor to be sensed by the target injured tissue/organ in the specific time frame, owing to complications arising from regeneration. In this research, two delivery methods (infusion pumping and local topical application) were applied to deliver recombinant human erythropoietin (rHuEPO) for skin regeneration. First, rHuEPO was given in deep second-degree scald injury sites in mice by infusion pump. Vascularization was remarkably higher in the rHuEPO pumping group than in controls. Second, local topical application of rHuEPO gel was given in deep second-degree scald injury sites in rats. Histological analysis showed that epithelialization rate was significantly higher in the rHuEPO gel-treated group than in controls. Immunohistochemical studies showed that the rHuEPO gel-treated group showed remarkably higher expression of skin regeneration makers than the control group. An accurate method for visualization and quantification of blood vessel networks in target areas has still not been developed up to this point, because of technical difficulties in detecting such thin blood vessels. A method which utilizes a series of steps to enhance the image, removes noise from image background, and tracks the vessels edges for vessel segmentation and quantification has been used in this study. Using image analysis methods, we were able to detect the microvascular networks of newly formed blood vessels (less than 500 μm thickness), which participate in the healing process, providing not only nutrition and oxygen to grow tissues but also necessary growth factors to grow tissue cells for complete skin regeneration. The rHuEPO-treated group showed higher expression of stem cell markers (CD 31, CD 90, CD 71, and nestin), which actively contribute to in-wound-healing processes for new hair follicle generation as well as skin regeneration. Collectively, both rHuEPO group pumping into the systemic circulation system, and injection into the local injury area, prompted mice and rats to form new blood vessel networks in scald injury sites, which significantly participate in the scald healing process. These results may lead to the development of novel treatments for scald wounds. PMID:26005333

Extraocular muscle regeneration in zebrafish requires late signals from Insulin-like growth factors.

PubMed

Saera-Vila, Alfonso; Louie, Ke'ale W; Sha, Cuilee; Kelly, Ryan M; Kish, Phillip E; Kahana, Alon

2018-01-01

Insulin-like growth factors (Igfs) are key regulators of key biological processes such as embryonic development, growth, and tissue repair and regeneration. The role of Igf in myogenesis is well documented and, in zebrafish, promotes fin and heart regeneration. However, the mechanism of action of Igf in muscle repair and regeneration is not well understood. Using adult zebrafish extraocular muscle (EOM) regeneration as an experimental model, we show that Igf1 receptor blockage using either chemical inhibitors (BMS754807 and NVP-AEW541) or translation-blocking morpholino oligonucleotides (MOs) reduced EOM regeneration. Zebrafish EOMs regeneration depends on myocyte dedifferentiation, which is driven by early epigenetic reprogramming and requires autophagy activation and cell cycle reentry. Inhibition of Igf signaling had no effect on either autophagy activation or cell proliferation, indicating that Igf signaling was not involved in the early reprogramming steps of regeneration. Instead, blocking Igf signaling produced hypercellularity of regenerating EOMs and diminished myosin expression, resulting in lack of mature differentiated muscle fibers even many days after injury, indicating that Igf was involved in late re-differentiation steps. Although it is considered the main mediator of myogenic Igf actions, Akt activation decreased in regenerating EOMs, suggesting that alternative signaling pathways mediate Igf activity in muscle regeneration. In conclusion, Igf signaling is critical for re-differentiation of reprogrammed myoblasts during late steps of zebrafish EOM regeneration, suggesting a regulatory mechanism for determining regenerated muscle size and timing of differentiation, and a potential target for regenerative therapy.

Three-Dimensional Printing Articular Cartilage: Recapitulating the Complexity of Native Tissue.

PubMed

Guo, Ting; Lembong, Josephine; Zhang, Lijie Grace; Fisher, John P

2017-06-01

In the past few decades, the field of tissue engineering combined with rapid prototyping (RP) techniques has been successful in creating biological substitutes that mimic tissues. Its applications in regenerative medicine have drawn efforts in research from various scientific fields, diagnostics, and clinical translation to therapies. While some areas of therapeutics are well developed, such as skin replacement, many others such as cartilage repair can still greatly benefit from tissue engineering and RP due to the low success and/or inefficiency of current existing, often surgical treatments. Through fabrication of complex scaffolds and development of advanced materials, RP provides a new avenue for cartilage repair. Computer-aided design and three-dimensional (3D) printing allow the fabrication of modeled cartilage scaffolds for repair and regeneration of damaged cartilage tissues. Specifically, the various processes of 3D printing will be discussed in details, both cellular and acellular techniques, covering the different materials, geometries, and operational printing conditions for the development of tissue-engineered articular cartilage. Finally, we conclude with some insights on future applications and challenges related to this technology, especially using 3D printing techniques to recapitulate the complexity of native structure for advanced cartilage regeneration.

Using Polymeric Materials to Control Stem Cell Behavior for Tissue Regeneration

PubMed Central

Zhang, Nianli; Kohn, David H.

2017-01-01

Patients with organ failure often suffer from increased morbidity and decreased quality of life. Current strategies of treating organ failure have limitations, including shortage of donor organs, low efficiency of grafts, and immunological problems. Tissue engineering emerged about two decades ago as a strategy to restore organ function with a living, functional engineered substitute. However, the ability to engineer a functional organ substitute is limited by a limited understanding of the interactions between materials and cells that are required to yield functional tissue equivalents. Polymeric materials are one of the most promising classes of materials for use in tissue engineering due to their biodegradability, flexibility in processing and property design, and the potential to use polymer properties to control cell function. Stem cells offer potential in tissue engineering because of their unique capacity to self renew and differentiate into neurogenic, osteogenic, chondrogenic, myogenic lineages under appropriate stimuli from extracellular components. This review examines recent advances in stem cell-polymer interactions for tissue regeneration, specifically highlighting control of polymer properties to direct adhesion, proliferation, and differentiation of stem cells, and how biomaterials can be designed to provide some of the stimuli to cells that the natural extracellular matrix does. PMID:22457178

Biomechanics and mechanobiology in functional tissue engineering

PubMed Central

Guilak, Farshid; Butler, David L.; Goldstein, Steven A.; Baaijens, Frank P.T.

2014-01-01

The field of tissue engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of “functional tissue engineering” has grown as a subfield of tissue engineering to address the challenges and questions on the role of biomechanics and mechanobiology in tissue engineering. Originally posed as a set of principles and guidelines for engineering of load-bearing tissues, functional tissue engineering has grown to encompass several related areas that have proven to have important implications for tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native tissues, scaffolds, and repair tissues; development of rationale criteria for the design and assessment of engineered tissues; investigation of the effects biomechanical factors on native and repair tissues, in vivo and in vitro; and development and application of computational models of tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered tissue replacements. PMID:24818797

Synchrotron microbeam irradiation induces neutrophil infiltration, thrombocyte attachment and selective vascular damage in vivo.

PubMed

Brönnimann, Daniel; Bouchet, Audrey; Schneider, Christoph; Potez, Marine; Serduc, Raphaël; Bräuer-Krisch, Elke; Graber, Werner; von Gunten, Stephan; Laissue, Jean Albert; Djonov, Valentin

2016-09-19

Our goal was the visualizing the vascular damage and acute inflammatory response to micro- and minibeam irradiation in vivo. Microbeam (MRT) and minibeam radiation therapies (MBRT) are tumor treatment approaches of potential clinical relevance, both consisting of parallel X-ray beams and allowing the delivery of thousands of Grays within tumors. We compared the effects of microbeams (25-100 μm wide) and minibeams (200-800 μm wide) on vasculature, inflammation and surrounding tissue changes during zebrafish caudal fin regeneration in vivo. Microbeam irradiation triggered an acute inflammatory response restricted to the regenerating tissue. Six hours post irradiation (6 hpi), it was infiltrated by neutrophils and fli1a(+) thrombocytes adhered to the cell wall locally in the beam path. The mature tissue was not affected by microbeam irradiation. In contrast, minibeam irradiation efficiently damaged the immature tissue at 6 hpi and damaged both the mature and immature tissue at 48 hpi. We demonstrate that vascular damage, inflammatory processes and cellular toxicity depend on the beam width and the stage of tissue maturation. Minibeam irradiation did not differentiate between mature and immature tissue. In contrast, all irradiation-induced effects of the microbeams were restricted to the rapidly growing immature tissue, indicating that microbeam irradiation could be a promising tumor treatment tool.

Myocardial tissue engineering using electrospun nanofiber composites

PubMed Central

Kim, Pyung-Hwan; Cho, Je-Yoel

2016-01-01

Emerging trends for cardiac tissue engineering are focused on increasing the biocompatibility and tissue regeneration ability of artificial heart tissue by incorporating various cell sources and bioactive molecules. Although primary cardiomyocytes can be successfully implanted, clinical applications are restricted due to their low survival rates and poor proliferation. To develop successful cardiovascular tissue regeneration systems, new technologies must be introduced to improve myocardial regeneration. Electrospinning is a simple, versatile technique for fabricating nanofibers. Here, we discuss various biodegradable polymers (natural, synthetic, and combinatorial polymers) that can be used for fiber fabrication. We also describe a series of fiber modification methods that can increase cell survival, proliferation, and migration and provide supporting mechanical properties by mimicking micro-environment structures, such as the extracellular matrix (ECM). In addition, the applications and types of nanofiber-based scaffolds for myocardial regeneration are described. Finally, fusion research methods combined with stem cells and scaffolds to improve biocompatibility are discussed. [BMB Reports 2016; 49(1): 26-36] PMID:26497579

Effect of the biodegradation rate controlled by pore structures in magnesium phosphate ceramic scaffolds on bone tissue regeneration in vivo.

PubMed

Kim, Ju-Ang; Lim, Jiwon; Naren, Raja; Yun, Hui-Suk; Park, Eui Kyun

2016-10-15

Similar to calcium phosphates, magnesium phosphate (MgP) ceramics have been shown to be biocompatible and support favorable conditions for bone cells. Micropores below 25μm (MgP25), between 25 and 53μm (MgP53), or no micropores (MgP0) were introduced into MgP scaffolds using different sizes of an NaCl template. The porosities of MgP25 and MgP53 were found to be higher than that of MgP0 because of their micro-sized pores. Both in vitro and in vivo analysis showed that MgP scaffolds with high porosity promoted rapid biodegradation. Implantation of the MgP0, MgP25, and MgP53 scaffolds into rabbit calvarial defects (with 4- and 6-mm diameters) was assessed at two times points (4 and 8weeks), followed by analysis of bone regeneration. The micro-CT and histologic analyses of the 4-mm defect showed that the MgP25 and MgP53 scaffolds were degraded completely at 4weeks with simultaneous bone and marrow-like structure regeneration. For the 6-mm defect, a similar pattern of regeneration was observed. These results indicate that the rate of degradation is associated with bone regeneration. The MgP25 and MgP53 scaffold-implanted bone showed a better lamellar structure and enhanced calcification compared to the MgP0 scaffold because of their porosity and degradation rate. Tartrate-resistant acid phosphatase (TRAP) staining indicated that the newly formed bone was undergoing maturation and remodeling. Overall, these data suggest that the pore architecture of MgP ceramic scaffolds greatly influence bone formation and remodeling activities and thus should be considered in the design of new scaffolds for long-term bone tissue regeneration. The pore structural conditions of scaffold, including porosity, pore size, pore morphology, and pore interconnectivity affect cell ingrowth, mechanical properties and biodegradabilities, which are key components of scaffold in bone tissue regeneration. In this study, we designed hierarchical pore structure of the magnesium phosphate (MgP) scaffold by combination of the 3D printing process, self-setting reaction and salt-leaching technique, and first studied the effect of pore structures of bioceramic scaffolds on bone tissue regeneration through both in vitro and in vivo studies (rabbit calvarial model). The MgP scaffolds with higher porosity promoted more rapid biodegradation and enhanced new bone formation and remodeling activities at the same time. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Exploiting endogenous fibrocartilage stem cells to regenerate cartilage and repair joint injury

PubMed Central

Embree, Mildred C.; Chen, Mo; Pylawka, Serhiy; Kong, Danielle; Iwaoka, George M.; Kalajzic, Ivo; Yao, Hai; Shi, Chancheng; Sun, Dongming; Sheu, Tzong-Jen; Koslovsky, David A.; Koch, Alia; Mao, Jeremy J.

2016-01-01

Tissue regeneration using stem cell-based transplantation faces many hurdles. Alternatively, therapeutically exploiting endogenous stem cells to regenerate injured or diseased tissue may circumvent these challenges. Here we show resident fibrocartilage stem cells (FCSCs) can be used to regenerate and repair cartilage. We identify FCSCs residing within the superficial zone niche in the temporomandibular joint (TMJ) condyle. A single FCSC spontaneously generates a cartilage anlage, remodels into bone and organizes a haematopoietic microenvironment. Wnt signals deplete the reservoir of FCSCs and cause cartilage degeneration. We also show that intra-articular treatment with the Wnt inhibitor sclerostin sustains the FCSC pool and regenerates cartilage in a TMJ injury model. We demonstrate the promise of exploiting resident FCSCs as a regenerative therapeutic strategy to substitute cell transplantation that could be beneficial for patients suffering from fibrocartilage injury and disease. These data prompt the examination of utilizing this strategy for other musculoskeletal tissues. PMID:27721375

Chitosan scaffolds containing calcium phosphate salts and rhBMP-2: in vitro and in vivo testing for bone tissue regeneration.

PubMed

Guzmán, Rodrigo; Nardecchia, Stefania; Gutiérrez, María C; Ferrer, María Luisa; Ramos, Viviana; del Monte, Francisco; Abarrategi, Ander; López-Lacomba, José Luis

2014-01-01

Numerous strategies that are currently used to regenerate bone depend on employing biocompatible materials exhibiting a scaffold structure. These scaffolds can be manufactured containing particular active compounds, such as hydroxyapatite precursors and/or different growth factors to enhance bone regeneration process. Herein, we have immobilized calcium phosphate salts (CPS) and bone morphogenetic protein 2 (BMP-2)--combined or alone--into chitosan scaffolds using ISISA process. We have analyzed whether the immobilized bone morphogenetic protein preserved its osteoinductive capability after manufacturing process as well as BMP-2 in vitro release kinetic. We have also studied both the in vitro and in vivo biocompatibility of the resulting scaffolds using a rabbit model. Results indicated that rhBMP-2 remained active in the scaffolds after the manufacturing process and that its release kinetic was different depending on the presence of CPS. In vitro and in vivo findings showed that cells grew more in scaffolds with both CPS and rhBMP-2 and that these scaffolds induced more bone formation in rabbit tibia. Thus chitosan scaffolds containing both CPS and rhBMP-2 were more osteoinductive than their counterparts alone indicating that could be useful for bone regeneration purposes, such as some applications in dentistry.

Shining Light on Nanotechnology to Help Repair and Regeneration

PubMed Central

Gupta, Asheesh; Avci, Pinar; Sadasivam, Magesh; Chandran, Rakkiyappan; Parizotto, Nivaldo; Vecchio, Daniela; Antunes-Melo, Wanessa C; Dai, Tianhong; Chiang, Long Y.; Hamblin, Michael R.

2012-01-01

Phototherapy can be used in two completely different but complementary therapeutic applications. While low level laser (or light) therapy (LLLT) uses red or near-infrared light alone to reduce inflammation, pain and stimulate tissue repair and regeneration, photodynamic therapy (PDT) uses the combination of light plus non-toxic dyes (called photosensitizers) to produce reactive oxygen species that can kill infectious microorganisms and cancer cells or destroy unwanted tissue (neo-vascularization in the choroid, atherosclerotic plaques in the arteries). The recent development of nanotechnology applied to medicine (nanomedicine) has opened a new front of advancement in the field of phototherapy and has provided hope for the development of nanoscale drug delivery platforms for effective killing of pathological cells and to promote repair and regeneration. Despite the well-known beneficial effects of phototherapy and nanomaterials in producing the killing of unwanted cells and promoting repair and regeneration, there are few reports that combine all three elements i.e. phototherapy, nanotechnology and, tissue repair and regeneration. However, these areas in all possible binary combinations have been addressed by many workers. The present review aims at highlighting the combined multi-model applications of phototherapy, nanotechnology and, reparative and regeneration medicine and outlines current strategies, future applications and limitations of nanoscale-assisted phototherapy for the management of cancers, microbial infections and other diseases, and to promote tissue repair and regeneration. PMID:22951919

Usefulness of myofascial flap without skin in contemporary oral and maxillofacial reconstruction.

PubMed

Wada, Takeshi; Nakatani, Ken; Hiraishi, Yukihiro; Negoro, Kenji; Iwagami, Yoshinobu; Fujita, Shigeyuki

2011-06-01

Pedicle myofascial graft should be considered in contemporary oral and maxillofacial reconstruction for the following reasons: 1) the pedicle myofascial unit is reliable and easily handled; 2) on the grafted myofascia in the oral cavity, the mucosa regenerates naturally with regard to suppleness and surface characteristics; and 3) vascularized myofascial coverage of tissues or materials is useful in some clinical situations. The purpose of this retrospective study was to evaluate the usefulness of this graft material. Using myofascial flaps from the pectoralis major muscle in 15 patients and from the platysma muscle in 11 patients, several types of reconstructive procedures were conducted in the Department of Oral and Maxillofacial Surgery, Wakayama Medical University. Myofascial tissue was used to cover the surgical defect and for regeneration of oral mucosa (24 patients), to prevent exposure of the mandibular reconstruction plate (4 patients), for prevention of wound breakdown and secondary infection in the oral cavity (2 patients), for vascularized coverage of free grafted autologous bone (2 patients), and for protection of large vessels after radical neck dissection (9 patients). Although partial flap necrosis or wound dehiscence was noticed in 3 patients with a platysma-myofascial graft, the healing process of all patients was favorable and required no additional operations. This procedure is most suitable for the reconstruction of small to medium-sized soft tissue defects in the oral cavity, because it induces the formation of nearly normal mucosa through epithelial regeneration without clear scar formation. Myofascial flap is a useful option in certain oral and maxillofacial reconstruction cases in which mucosal regeneration and/or vascularized soft tissue coverage are required. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Proliferation zones in the axolotl brain and regeneration of the telencephalon

PubMed Central

2013-01-01

Background Although the brains of lower vertebrates are known to exhibit somewhat limited regeneration after incisional or stab wounds, the Urodele brain exhibits extensive regeneration after massive tissue removal. Discovering whether and how neural progenitor cells that reside in the ventricular zones of Urodeles proliferate to mediate tissue repair in response to injury may produce novel leads for regenerative strategies. Here we show that endogenous neural progenitor cells resident to the ventricular zone of Urodeles spontaneously proliferate, producing progeny that migrate throughout the telencephalon before terminally differentiating into neurons. These progenitor cells appear to be responsible for telencephalon regeneration after tissue removal and their activity may be up-regulated by injury through an olfactory cue. Results There is extensive proliferation of endogenous neural progenitor cells throughout the ventricular zone of the adult axolotl brain. The highest levels are observed in the telencephalon, especially the dorsolateral aspect, and cerebellum. Lower levels are observed in the mesencephalon and rhombencephalon. New cells produced in the ventricular zone migrate laterally, dorsally and ventrally into the surrounding neuronal layer. After migrating from the ventricular zone, the new cells primarily express markers of neuronal differentiative fates. Large-scale telencephalic tissue removal stimulates progenitor cell proliferation in the ventricular zone of the damaged region, followed by proliferation in the tissue that surrounds the healing edges of the wound until the telencephalon has completed regeneration. The proliferative stimulus appears to reside in the olfactory system, because telencephalic regeneration does not occur in the brains of olfactory bulbectomized animals in which the damaged neural tissue simply heals over. Conclusion There is a continual generation of neuronal cells from neural progenitor cells located within the ventricular zone of the axolotl brain. Variable rates of proliferation were detected across brain regions. These neural progenitor cells appear to mediate telencephalic tissue regeneration through an injury-induced olfactory cue. Identification of this cue is our future goal. PMID:23327114

Proliferation zones in the axolotl brain and regeneration of the telencephalon.

PubMed

Maden, Malcolm; Manwell, Laurie A; Ormerod, Brandi K

2013-01-17

Although the brains of lower vertebrates are known to exhibit somewhat limited regeneration after incisional or stab wounds, the Urodele brain exhibits extensive regeneration after massive tissue removal. Discovering whether and how neural progenitor cells that reside in the ventricular zones of Urodeles proliferate to mediate tissue repair in response to injury may produce novel leads for regenerative strategies. Here we show that endogenous neural progenitor cells resident to the ventricular zone of Urodeles spontaneously proliferate, producing progeny that migrate throughout the telencephalon before terminally differentiating into neurons. These progenitor cells appear to be responsible for telencephalon regeneration after tissue removal and their activity may be up-regulated by injury through an olfactory cue. There is extensive proliferation of endogenous neural progenitor cells throughout the ventricular zone of the adult axolotl brain. The highest levels are observed in the telencephalon, especially the dorsolateral aspect, and cerebellum. Lower levels are observed in the mesencephalon and rhombencephalon. New cells produced in the ventricular zone migrate laterally, dorsally and ventrally into the surrounding neuronal layer. After migrating from the ventricular zone, the new cells primarily express markers of neuronal differentiative fates. Large-scale telencephalic tissue removal stimulates progenitor cell proliferation in the ventricular zone of the damaged region, followed by proliferation in the tissue that surrounds the healing edges of the wound until the telencephalon has completed regeneration. The proliferative stimulus appears to reside in the olfactory system, because telencephalic regeneration does not occur in the brains of olfactory bulbectomized animals in which the damaged neural tissue simply heals over. There is a continual generation of neuronal cells from neural progenitor cells located within the ventricular zone of the axolotl brain. Variable rates of proliferation were detected across brain regions. These neural progenitor cells appear to mediate telencephalic tissue regeneration through an injury-induced olfactory cue. Identification of this cue is our future goal.

'Pre-prosthetic use of poly(lactic-co-glycolic acid) membranes treated with oxygen plasma and TiO2 nanocomposite particles for guided bone regeneration processes'.

PubMed

Castillo-Dalí, Gabriel; Castillo-Oyagüe, Raquel; Terriza, Antonia; Saffar, Jean-Louis; Batista-Cruzado, Antonio; Lynch, Christopher D; Sloan, Alastair J; Gutiérrez-Pérez, José-Luis; Torres-Lagares, Daniel

2016-04-01

Guided bone regeneration (GBR) processes are frequently necessary to achieve appropriate substrates before the restoration of edentulous areas. This study aimed to evaluate the bone regeneration reliability of a new poly-lactic-co-glycolic acid (PLGA) membrane after treatment with oxygen plasma (PO2) and titanium dioxide (TiO2) composite nanoparticles. Circumferential bone defects (diameter: 10mm; depth: 3mm) were created on the parietal bones of eight experimentation rabbits and were randomly covered with control membranes (Group 1: PLGA) or experimental membranes (Group 2: PLGA/PO2/TiO2). The animals were euthanized two months afterwards, and a morphologic study was then performed under microscope using ROI (region of interest) colour analysis. Percentage of new bone formation, length of mineralised bone formed in the grown defects, concentration of osteoclasts, and intensity of osteosynthetic activity were assessed. Comparisons among the groups and with the original bone tissue were made using the Kruskal-Wallis test. The level of significance was set in advance at a=0.05. The experimental group recorded higher values for new bone formation, mineralised bone length, and osteoclast concentration; this group also registered the highest osteosynthetic activity. Bone layers in advanced formation stages and low proportions of immature tissue were observed in the study group. The functionalised membranes showed the best efficacy for bone regeneration. The addition of TiO2 nanoparticles onto PLGA/PO2 membranes for GBR processes may be a promising technique to restore bone dimensions and anatomic contours as a prerequisite to well-supported and natural-appearing prosthetic rehabilitations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Insights into the key roles of epigenetics in matrix macromolecules-associated wound healing.

PubMed

Piperigkou, Zoi; Götte, Martin; Theocharis, Achilleas D; Karamanos, Nikos K

2017-10-24

Extracellular matrix (ECM) is a dynamic network of macromolecules, playing a regulatory role in cell functions, tissue regeneration and remodeling. Wound healing is a tissue repair process necessary for the maintenance of the functionality of tissues and organs. This highly orchestrated process is divided into four temporally overlapping phases, including hemostasis, inflammation, proliferation and tissue remodeling. The dynamic interplay between ECM and resident cells exerts its critical role in many aspects of wound healing, including cell proliferation, migration, differentiation, survival, matrix degradation and biosynthesis. Several epigenetic regulatory factors, such as the endogenous non-coding microRNAs (miRNAs), are the drivers of the wound healing response. microRNAs have pivotal roles in regulating ECM composition during wound healing and dermal regeneration. Their expression is associated with the distinct phases of wound healing and they serve as target biomarkers and targets for systematic regulation of wound repair. In this article we critically present the importance of epigenetics with particular emphasis on miRNAs regulating ECM components (i.e. glycoproteins, proteoglycans and matrix proteases) that are key players in wound healing. The clinical relevance of miRNA targeting as well as the delivery strategies designed for clinical applications are also presented and discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrospun nanofibers for neural tissue engineering

NASA Astrophysics Data System (ADS)

Xie, Jingwei; MacEwan, Matthew R.; Schwartz, Andrea G.; Xia, Younan

2010-01-01

Biodegradable nanofibers produced by electrospinning represent a new class of promising scaffolds to support nerve regeneration. We begin with a brief discussion on the electrospinning of nanofibers and methods for controlling the structure, porosity, and alignment of the electrospun nanofibers. The methods include control of the nanoscale morphology and microscale alignment of the nanofibers, as well as the fabrication of macroscale, three-dimensional tubular structures. We then highlight recent studies that utilize electrospun nanofibers to manipulate biological processes relevant to nervous tissue regeneration, including stem cell differentiation, guidance of neurite extension, and peripheral nerve injury treatments. The main objective of this feature article is to provide valuable insights into methods for investigating the mechanisms of neurite growth on novel nanofibrous scaffolds and optimization of the nanofiber scaffolds and conduits for repairing peripheral nerve injuries.

Tissue culture-induced genetic and epigenetic variation in triticale (× Triticosecale spp. Wittmack ex A. Camus 1927) regenerants.

PubMed

Machczyńska, Joanna; Zimny, Janusz; Bednarek, Piotr Tomasz

2015-10-01

Plant regeneration via in vitro culture can induce genetic and epigenetic variation; however, the extent of such changes in triticale is not yet understood. In the present study, metAFLP, a variation of methylation-sensitive amplified fragment length polymorphism analysis, was used to investigate tissue culture-induced variation in triticale regenerants derived from four distinct genotypes using androgenesis and somatic embryogenesis. The metAFLP technique enabled identification of both sequence and DNA methylation pattern changes in a single experiment. Moreover, it was possible to quantify subtle effects such as sequence variation, demethylation, and de novo methylation, which affected 19, 5.5, 4.5% of sites, respectively. Comparison of variation in different genotypes and with different in vitro regeneration approaches demonstrated that both the culture technique and genetic background of donor plants affected tissue culture-induced variation. The results showed that the metAFLP approach could be used for quantification of tissue culture-induced variation and provided direct evidence that in vitro plant regeneration could cause genetic and epigenetic variation.

In vitro 3D regeneration-like growth of human patient brain tissue.

PubMed

Tang-Schomer, M D; Wu, W B; Kaplan, D L; Bookland, M J

2018-05-01

In vitro culture of primary neurons is widely adapted with embryonic but not mature brain tissue. Here, we extended a previously developed bioengineered three-dimensional (3D) embryonic brain tissue model to resected normal patient brain tissue in an attempt to regenerate human neurons in vitro. Single cells and small sized (diameter < 100 μm) spheroids from dissociated brain tissue were seeded into 3D silk fibroin-based scaffolds, with or without collagen or Matrigel, and compared with two-dimensional cultures and scaffold-free suspension cultures. Changes of cell phenotypes (neuronal, astroglial, neural progenitor, and neuroepithelial) were quantified with flow cytometry and analyzed with a new method of statistical analysis specifically designed for percentage comparison. Compared with a complete lack of viable cells in conventional neuronal cell culture condition, supplements of vascular endothelial growth factor-containing pro-endothelial cell condition led to regenerative growth of neurons and astroglial cells from "normal" human brain tissue of epilepsy surgical patients. This process involved delayed expansion of Nestin+ neural progenitor cells, emergence of TUJ1+ immature neurons, and Vimentin+ neuroepithelium-like cell sheet formation in prolonged cultures (14 weeks). Micro-tissue spheroids, but not single cells, supported the brain tissue growth, suggesting importance of preserving native cell-cell interactions. The presence of 3D scaffold, but not hydrogel, allowed for Vimentin+ cell expansion, indicating a different growth mechanism than pluripotent cell-based brain organoid formation. The slow and delayed process implied an origin of quiescent neural precursors in the neocortex tissue. Further optimization of the 3D tissue model with primary human brain cells could provide personalized brain disease models. Copyright © 2018 John Wiley & Sons, Ltd.

Limb regeneration is impaired in an adult zebrafish model of diabetes mellitus.

PubMed

Olsen, Ansgar S; Sarras, Michael P; Intine, Robert V

2010-01-01

The zebrafish (Danio rerio) is an established model organism for the study of developmental processes, human disease, and tissue regeneration. We report that limb regeneration is severely impaired in our newly developed adult zebrafish model of type I diabetes mellitus. Intraperitoneal streptozocin injection of adult, wild-type zebrafish results in a sustained hyperglycemic state as determined by elevated fasting blood glucose values and increased glycation of serum protein. Serum insulin levels are also decreased and pancreas immunohistochemisty revealed a decreased amount of insulin signal in hyperglycemic fish. Additionally, the diabetic complications of retinal thinning and glomerular basement membrane thickening (early signs of retinopathy and nephropathy) resulting from the hyperglycemic state were evident in streptozocin-injected fish at 3 weeks. Most significantly, limb regeneration, following caudal fin amputation, is severely impaired in diabetic zebrafish and nonspecific toxic effects outside the pancreas were not found to contribute to impaired limb regeneration. This experimental system using adult zebrafish facilitates a broad spectrum of genetic and molecular approaches to study regeneration in the diabetic background. © 2010 by the Wound Healing Society.

Review paper: DNA delivery strategies to promote periodontal regeneration.

PubMed

Elangovan, Satheesh; Karimbux, Nadeem

2010-07-01

Periodontal diseases are caused by bacteria with an inflammatory component that result in the loss of bone and soft tissue around the neck of the teeth. Recent therapies allow clinicians to regenerate some of the lost structures of the periodontium. Regeneration of these lost supporting structures is a highly orchestrated process, involving various cellular and molecular players, leading to the complete restoration of the periodontium (the tooth-supporting apparatus). The introduction of growth factors has positively influenced the clinical outcome of the existing regenerative procedures but the supra-physiological doses and the high cost associated with these growth factors can be drawbacks. Gene therapy may offer some interesting advantages to current therapies. In the field of periodontology, several studies have been conducted to explore the efficacy of delivering the DNA of key growth factors using viral vectors in both periodontal and peri-implant bone regeneration. Relatively few studies have explored the application of nonviral gene therapy in periodontal regeneration. This article is aimed at reviewing the studies conducted so far using viral and nonviral gene delivery approaches to achieve periodontal and peri-implant bone regeneration.

Identification of neoblast- and regeneration-specific miRNAs in the planarian Schmidtea mediterranea

PubMed Central

Sasidharan, Vidyanand; Lu, Yi-Chien; Bansal, Dhiru; Dasari, Pranavi; Poduval, Deepak; Seshasayee, Aswin; Resch, Alissa M.; Graveley, Brenton R.; Palakodeti, Dasaradhi

2013-01-01

In recent years, the planarian Schmidtea mediterranea has emerged as a tractable model system to study stem cell biology and regeneration. MicroRNAs are small RNA species that control gene expression by modulating translational repression and mRNA stability and have been implicated in the regulation of various cellular processes. Though recent studies have identified several miRNAs in S. mediterranea, their expression in neoblast subpopulations and during regeneration has not been examined. Here, we identify several miRNAs whose expression is enriched in different neoblast subpopulations and in regenerating tissue at different time points in S. mediterranea. Some of these miRNAs were enriched within 3 h post-amputation and may, therefore, play a role in wound healing and/or neoblast migration. Our results also revealed miRNAs, such as sme-miR-2d-3p and the sme-miR-124 family, whose expression is enriched in the cephalic ganglia, are also expressed in the brain primordium during CNS regeneration. These results provide new insight into the potential biological functions of miRNAs in neoblasts and regeneration in planarians. PMID:23974438

Hydrogel based cartilaginous tissue regeneration: recent insights and technologies.

PubMed

Chuah, Yon Jin; Peck, Yvonne; Lau, Jia En Josias; Hee, Hwan Tak; Wang, Dong-An

2017-03-28

Hydrogels have been extensively employed as an attractive biomaterial to address numerous existing challenges in the fields of regenerative medicine and research because of their unique properties such as the capability to encapsulate cells, high water content, ease of modification, low toxicity, injectability, in situ spatial fit and biocompatibility. These inherent properties have created many opportunities for hydrogels as a scaffold or a cell/drug carrier in tissue regeneration, especially in the field of cartilaginous tissue such as articular cartilage and intervertebral discs. A concise overview of the anatomy/physiology of these cartilaginous tissues and their pathophysiology, epidemiology and existing clinical treatments will be briefly described. This review article will discuss the current state-of-the-art of various polymers and developing strategies that are explored in establishing different technologies for cartilaginous tissue regeneration. In particular, an innovative approach to generate scaffold-free cartilaginous tissue via a transient hydrogel scaffolding system for disease modeling to pre-clinical trials will be examined. Following that, the article reviews numerous hydrogel-based medical implants used in clinical treatment of osteoarthritis and degenerated discs. Last but not least, the challenges and future directions of hydrogel based medical implants in the regeneration of cartilaginous tissue are also discussed.

Regenerative responses after mild heart injuries for cardiomyocyte proliferation in zebrafish

PubMed Central

Itou, Junji; Akiyama, Ryutaro; Pehoski, Steve; Yu, Xiaodan; Kawakami, Hiroko; Kawakami, Yasuhiko

2014-01-01

Background The zebrafish heart regenerates after various severe injuries. Common processes of heart regeneration are cardiomyocyte proliferation, activation of epicardial tissue and neovascularization. In order to further characterize heart regeneration processes, we introduced milder injuries and compared responses to those induced by ventricular apex resection, a widely used injury method. We used scratching of the ventricular surface and puncturing of the ventricle with a fine tungsten needle as injury inducing techniques. Results Scratching the ventricular surface induced subtle cardiomyocyte proliferation and responses of the epicardium. Endothelial cell accumulation was limited to the surface of the heart. Ventricular puncture induced cardiomyocyte proliferation, endocardial and epicardial activation and neo-vascularization, similar to the resection method. However, the degree of the responses was milder, correlating with milder injury. Sham operation induced epicardial aldh1a2 expression but not tbx18 and WT1. Conclusions Puncturing the ventricle induces responses equivalent to resection at milder degrees in a shorter time frame and would be used as simple injury model. Scratching the ventricle did not induce heart regeneration and would be used for studying wound responses to epicardium. PMID:25074230

Cartilage extracellular matrix as a biomaterial for cartilage regeneration.

PubMed

Kiyotake, Emi A; Beck, Emily C; Detamore, Michael S

2016-11-01

The extracellular matrix (ECM) of various tissues possesses the model characteristics that biomaterials for tissue engineering strive to mimic; however, owing to the intricate hierarchical nature of the ECM, it has yet to be fully characterized and synthetically fabricated. Cartilage repair remains a challenge because the intrinsic properties that enable its durability and long-lasting function also impede regeneration. In the last decade, cartilage ECM has emerged as a promising biomaterial for regenerating cartilage, partly because of its potentially chondroinductive nature. As this research area of cartilage matrix-based biomaterials emerged, investigators facing similar challenges consequently developed convergent solutions in constructing robust and bioactive scaffolds. This review discusses the challenges, emerging trends, and future directions of cartilage ECM scaffolds, including a comparison between two different forms of cartilage matrix: decellularized cartilage (DCC) and devitalized cartilage (DVC). To overcome the low permeability of cartilage matrix, physical fragmentation greatly enhances decellularization, although the process itself may reduce the chondroinductivity of fabricated scaffolds. The less complex processing of a scaffold composed of DVC, which has not been decellularized, appears to have translational advantages and potential chondroinductive and mechanical advantages over DCC, without detrimental immunogenicity, to ultimately enhance cartilage repair in a clinically relevant way. © 2016 New York Academy of Sciences.

Macrophages in tissue repair, regeneration, and fibrosis

PubMed Central

Wynn, Thomas A.; Vannella, Kevin M.

2016-01-01

Inflammatory monocytes and resident tissue macrophages are key regulators of tissue repair, regeneration, and fibrosis. Following tissue injury, monocytes and macrophages undergo marked phenotypic and functional changes to play critical roles during the initiation, maintenance, and resolution phases of tissue repair. Disturbances in macrophage function can lead to aberrant repair, with uncontrolled inflammatory mediator and growth factor production, deficient generation of anti-inflammatory macrophages, or failed communication between macrophages and epithelial cells, endothelial cells, fibroblasts, and stem or tissue progenitor cells all contributing to a state of persistent injury, which may lead to the development of pathological fibrosis. In this review, we discuss the mechanisms that instruct macrophages to adopt pro-inflammatory, pro-wound healing, pro-fibrotic, anti-inflammatory, anti-fibrotic, pro-resolving, and tissue regenerating phenotypes following injury, and highlight how some of these mechanisms and macrophage activation states could be exploited therapeutically. PMID:26982353

Optical coherence tomography: A new strategy to image planarian regeneration

NASA Astrophysics Data System (ADS)

Lin, Yu-Sheng; Chu, Chin-Chou; Lin, Jen-Jen; Chang, Chien-Cheng; Wang, Chun-Chieh; Wang, Chiao-Yin; Tsui, Po-Hsiang

2014-09-01

The planarian is widely used as a model for studying tissue regeneration. In this study, we used optical coherence tomography (OCT) for the real-time, high-resolution imaging of planarian tissue regeneration. Five planaria were sliced transversely to produce 5 head and 5 tail fragments. During a 2-week regeneration period, OCT images of the planaria were acquired to analyze the signal attenuation rates, intensity ratios, and image texture features (including contrast, correlation, homogeneity, energy, and entropy) to compare the primitive and regenerated tissues. In the head and tail fragments, the signal attenuation rates of the regenerated fragments decreased from -0.2 dB/μm to -0.05 dB/μm, between Day 1 and Day 6, and then increased to -0.2 dB/μm on Day 14. The intensity ratios decreased to approximately 0.8 on Day 6, and increased to between 0.8 and 0.9 on Day 14. The texture parameters of contrast, correlation, and homogeneity exhibited trends similar to the signal attenuation rates and intensity ratios during the planarian regeneration. The proposed OCT parameters might provide biological information regarding cell apoptosis and the formation of a mass of new cells during planarian regeneration. Therefore, OCT imaging is a potentially effective method for planarian studies.

De novo transcriptome sequencing of axolotl blastema for identification of differentially expressed genes during limb regeneration

PubMed Central

2013-01-01

Background Salamanders are unique among vertebrates in their ability to completely regenerate amputated limbs through the mediation of blastema cells located at the stump ends. This regeneration is nerve-dependent because blastema formation and regeneration does not occur after limb denervation. To obtain the genomic information of blastema tissues, de novo transcriptomes from both blastema tissues and denervated stump ends of Ambystoma mexicanum (axolotls) 14 days post-amputation were sequenced and compared using Solexa DNA sequencing. Results The sequencing done for this study produced 40,688,892 reads that were assembled into 307,345 transcribed sequences. The N50 of transcribed sequence length was 562 bases. A similarity search with known proteins identified 39,200 different genes to be expressed during limb regeneration with a cut-off E-value exceeding 10-5. We annotated assembled sequences by using gene descriptions, gene ontology, and clusters of orthologous group terms. Targeted searches using these annotations showed that the majority of the genes were in the categories of essential metabolic pathways, transcription factors and conserved signaling pathways, and novel candidate genes for regenerative processes. We discovered and confirmed numerous sequences of the candidate genes by using quantitative polymerase chain reaction and in situ hybridization. Conclusion The results of this study demonstrate that de novo transcriptome sequencing allows gene expression analysis in a species lacking genome information and provides the most comprehensive mRNA sequence resources for axolotls. The characterization of the axolotl transcriptome can help elucidate the molecular mechanisms underlying blastema formation during limb regeneration. PMID:23815514

Fast revascularization of the injured area is essential to support zebrafish heart regeneration

PubMed Central

Marín-Juez, Rubén; Marass, Michele; Gauvrit, Sebastien; Rossi, Andrea; Lai, Shih-Lei; Materna, Stefan C.; Black, Brian L.; Stainier, Didier Y. R.

2016-01-01

Zebrafish have a remarkable capacity to regenerate their heart. Efficient replenishment of lost tissues requires the activation of different cell types including the epicardium and endocardium. A complex set of processes is subsequently needed to support cardiomyocyte repopulation. Previous studies have identified important determinants of heart regeneration; however, to date, how revascularization of the damaged area happens remains unknown. Here, we show that angiogenic sprouting into the injured area starts as early as 15 h after injury. To analyze the role of vegfaa in heart regeneration, we used vegfaa mutants rescued to adulthood by vegfaa mRNA injections at the one-cell stage. Surprisingly, vegfaa mutants develop coronaries and revascularize after injury. As a possible explanation for these observations, we find that vegfaa mutant hearts up-regulate the expression of potentially compensating genes. Therefore, to overcome the lack of a revascularization phenotype in vegfaa mutants, we generated fish expressing inducible dominant negative Vegfaa. These fish displayed minimal revascularization of the damaged area. In the absence of fast angiogenic revascularization, cardiomyocyte proliferation did not occur, and the heart failed to regenerate, retaining a fibrotic scar. Hence, our data show that a fast endothelial invasion allows efficient revascularization of the injured area, which is necessary to support replenishment of new tissue and achieve efficient heart regeneration. These findings revisit the model where neovascularization is considered to happen concomitant with the formation of new muscle. Our work also paves the way for future studies designed to understand the molecular mechanisms that regulate fast revascularization. PMID:27647901

Nanotechnology for regenerative medicine.

PubMed

Khang, Dongwoo; Carpenter, Joseph; Chun, Young Wook; Pareta, Rajesh; Webster, Thomas J

2010-08-01

Future biomaterials must simultaneously enhance tissue regeneration while minimizing immune responses and inhibiting infection. While the field of tissue engineering has promised to develop materials that can promote tissue regeneration for the entire body, such promises have not become reality. However, tissue engineering has experienced great progress due to the recent emergence of nanotechnology. Specifically, it has now been well established that increased tissue regeneration can be achieved on almost any surface by employing novel nano-textured surface features. Numerous studies have reported that nanotechnology accelerates various regenerative therapies, such as those for the bone, vascular, heart, cartilage, bladder and brain tissue. Various nano-structured polymers and metals (alloys) have been investigated for their bio (and cyto) compatibility properties. This review paper discusses several of the latest nanotechnology findings in regenerative medicine (also now called nanomedicine) as well as their relative levels of success.

Tissue-engineered trachea regeneration using decellularized trachea matrix treated with laser micropore technique.

PubMed

Xu, Yong; Li, Dan; Yin, Zongqi; He, Aijuan; Lin, Miaomiao; Jiang, Gening; Song, Xiao; Hu, Xuefei; Liu, Yi; Wang, Jinpeng; Wang, Xiaoyun; Duan, Liang; Zhou, Guangdong

2017-08-01

Tissue-engineered trachea provides a promising approach for reconstruction of long segmental tracheal defects. However, a lack of ideal biodegradable scaffolds greatly restricts its clinical translation. Decellularized trachea matrix (DTM) is considered a proper scaffold for trachea cartilage regeneration owing to natural tubular structure, cartilage matrix components, and biodegradability. However, cell residual and low porosity of DTM easily result in immunogenicity and incomplete cartilage regeneration. To address these problems, a laser micropore technique (LMT) was applied in the current study to modify trachea sample porosity to facilitate decellular treatment and cell ingrowth. Decellularization processing demonstrated that cells in LMT treated samples were more easily removed compared with untreated native trachea. Furthermore, after optimizing the protocols of LMT and decellular treatments, the LMT-treated DTM (LDTM) could retain their original tubular shape with only mild extracellular matrix damage. After seeding with chondrocytes and culture in vitro for 8 weeks, the cell-LDTM constructs formed tubular cartilage with relatively homogenous cell distribution in both micropores and bilateral surfaces. In vivo results further confirmed that the constructs could form mature tubular cartilage with increased DNA and cartilage matrix contents, as well as enhanced mechanical strength, compared with native trachea. Collectively, these results indicate that LDTM is an ideal scaffold for tubular cartilage regeneration and, thus, provides a promising strategy for functional reconstruction of trachea cartilage. Lacking ideal biodegradable scaffolds greatly restricts development of tissue-engineered trachea. Decellularized trachea matrix (DTM) is considered a proper scaffold for trachea cartilage regeneration. However, cell residual and low porosity of DTM easily result in immunogenicity and incomplete cartilage regeneration. By laser micropore technique (LMT), the current study efficiently enhanced the porosity and decellularized efficacy of DTM. The LMT-treated DTM basically retained the original tubular shape with mild matrix damage. After chondrocyte seeding followed by in vitro culture and in vivo implantation, the constructs formed mature tubular cartilage with matrix content and mechanical strength similar to native trachea. The current study provides an ideal scaffold and a promising strategy for cartilage regeneration and functional reconstruction of trachea. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

3D Printing of Scaffolds for Tissue Regeneration Applications

PubMed Central

Do, Anh-Vu; Khorsand, Behnoush; Geary, Sean M.; Salem, Aliasger K.

2015-01-01

The current need for organ and tissue replacement, repair and regeneration for patients is continually growing such that supply is not meeting the high demand primarily due to a paucity of donors as well as biocompatibility issues that lead to immune rejection of the transplant. In an effort to overcome these drawbacks, scientists working in the field of tissue engineering and regenerative medicine have investigated the use of scaffolds as an alternative to transplantation. These scaffolds are designed to mimic the extracellular matrix (ECM) by providing structural support as well as promoting attachment, proliferation, and differentiation with the ultimate goal of yielding functional tissues or organs. Initial attempts at developing scaffolds were problematic and subsequently inspired a growing interest in 3D printing as a mode for generating scaffolds. Utilizing three-dimensional printing (3DP) technologies, ECM-like scaffolds can be produced with a high degree of complexity and precision, where fine details can be included at a micron level. In this review, we discuss the criteria for printing viable and functional scaffolds, scaffolding materials, and 3DP technologies used to print scaffolds for tissue engineering. A hybrid approach, employing both natural and synthetic materials, as well as multiple printing processes may be the key to yielding an ECM-like scaffold with high mechanical strength, porosity, interconnectivity, biocompatibility, biodegradability, and high processability. Creating such biofunctional scaffolds could potentially help to meet the demand by patients for tissues and organs without having to wait or rely on donors for transplantation. PMID:26097108

Regenerative therapy and tissue engineering for the treatment of end-stage cardiac failure

PubMed Central

Finosh, G.T.; Jayabalan, Muthu

2012-01-01

Regeneration of myocardium through regenerative therapy and tissue engineering is appearing as a prospective treatment modality for patients with end-stage heart failure. Focusing on this area, this review highlights the new developments and challenges in the regeneration of myocardial tissue. The role of various cell sources, calcium ion and cytokine on the functional performance of regenerative therapy is discussed. The evolution of tissue engineering and the role of tissue matrix/scaffold, cell adhesion and vascularisation on tissue engineering of cardiac tissue implant are also discussed. PMID:23507781

Regenerative therapy and tissue engineering for the treatment of end-stage cardiac failure: new developments and challenges.

PubMed

Finosh, G T; Jayabalan, Muthu

2012-01-01

Regeneration of myocardium through regenerative therapy and tissue engineering is appearing as a prospective treatment modality for patients with end-stage heart failure. Focusing on this area, this review highlights the new developments and challenges in the regeneration of myocardial tissue. The role of various cell sources, calcium ion and cytokine on the functional performance of regenerative therapy is discussed. The evolution of tissue engineering and the role of tissue matrix/scaffold, cell adhesion and vascularisation on tissue engineering of cardiac tissue implant are also discussed.

Orthogonal muscle fibres have different instructive roles in planarian regeneration.

PubMed

Scimone, M Lucila; Cote, Lauren E; Reddien, Peter W

2017-11-30

The ability to regenerate missing body parts exists throughout the animal kingdom. Positional information is crucial for regeneration, but how it is harboured and used by differentiated tissues is poorly understood. In planarians, positional information has been identified from study of phenotypes caused by RNA interference in which the wrong tissues are regenerated. For example, inhibition of the Wnt signalling pathway leads to regeneration of heads in place of tails. Characterization of these phenotypes has led to the identification of position control genes (PCGs)-genes that are expressed in a constitutive and regional manner and are associated with patterning. Most PCGs are expressed within planarian muscle; however, how muscle is specified and how different muscle subsets affect regeneration is unknown. Here we show that different muscle fibres have distinct regulatory roles during regeneration in the planarian Schmidtea mediterranea. myoD is required for formation of a specific muscle cell subset: the longitudinal fibres, oriented along the anterior-posterior axis. Loss of longitudinal fibres led to complete regeneration failure because of defects in regeneration initiation. A different transcription factor-encoding gene, nkx1-1, is required for the formation of circular fibres, oriented along the medial-lateral axis. Loss of circular fibres led to a bifurcated anterior-posterior axis with fused heads forming in single anterior blastemas. Whereas muscle is often viewed as a strictly contractile tissue, these findings reveal that different muscle types have distinct and specific regulatory roles in wound signalling and patterning to enable regeneration.

Ghrelin knockout mice display defective skeletal muscle regeneration and impaired satellite cell self-renewal.

PubMed

Angelino, Elia; Reano, Simone; Bollo, Alessandro; Ferrara, Michele; De Feudis, Marilisa; Sustova, Hana; Agosti, Emanuela; Clerici, Sara; Prodam, Flavia; Tomasetto, Catherine-Laure; Graziani, Andrea; Filigheddu, Nicoletta

2018-05-30

Muscle regeneration depends on satellite cells (SCs), quiescent precursors that, in consequence of injury or pathological states such as muscular dystrophies, activate, proliferate, and differentiate to repair the damaged tissue. A subset of SCs undergoes self-renewal, thus preserving the SC pool and its regenerative potential. The peptides produced by the ghrelin gene, i.e., acylated ghrelin (AG), unacylated ghrelin (UnAG), and obestatin (Ob), affect skeletal muscle biology in several ways, not always with overlapping effects. In particular, UnAG and Ob promote SC self-renewal and myoblast differentiation, thus fostering muscle regeneration. To delineate the endogenous contribution of preproghrelin in muscle regeneration, we evaluated the repair process in Ghrl -/- mice upon CTX-induced injury. Although muscles from Ghrl -/- mice do not visibly differ from WT muscles in term of weight, structure, and SCs content, muscle regeneration after CTX-induced injury is impaired in Ghrl -/- mice, indicating that ghrelin-derived peptides actively participate in muscle repair. Remarkably, the lack of ghrelin gene impacts SC self-renewal during regeneration. Although we cannot discern the specific Ghrl-derived peptide responsible for such activities, these data indicate that Ghrl contributes to a proper muscle regeneration.

Original and regenerating lizard tail cartilage contain putative resident stem/progenitor cells.

PubMed

Alibardi, Lorenzo

2015-11-01

Regeneration of cartilaginous tissues is limited in mammals but it occurs with variable extension in lizards (reptiles), including in their vertebrae. The ability of lizard vertebrae to regenerate cartilaginous tissue that is later replaced with bone has been analyzed using tritiated thymidine autoradiography and 5BrdU immunocytochemistry after single pulse or prolonged-pulse and chase experiments. The massive cartilage regeneration that can restore broad vertebral regions and gives rise to a long cartilaginous tube in the regenerating tail, depends from the permanence of some chondrogenic cells within adult vertebrae. Few cells that retain tritiated thymidine or 5-bromodeoxy-uridine for over 35 days are mainly localized in the inter-vertebral cartilage and in sparse chondrogenic regions of the neural arch of the vertebrae, suggesting that they are putative resident stem/progenitor cells. The study supports previous hypothesis indicating that the massive regeneration of the cartilaginous tissue in damaged vertebrae and in the regenerating tail of lizards derive from resident stem cells mainly present in the cartilaginous areas of the vertebrae including in the perichondrium that are retained in adult lizards as growing centers for most of their lifetime. Copyright © 2015 Elsevier Ltd. All rights reserved.

Low-temperature deposition manufacturing: A novel and promising rapid prototyping technology for the fabrication of tissue-engineered scaffold.

PubMed

Liu, Wei; Wang, Daming; Huang, Jianghong; Wei, You; Xiong, Jianyi; Zhu, Weimin; Duan, Li; Chen, Jielin; Sun, Rong; Wang, Daping

2017-01-01

Developed in recent years, low-temperature deposition manufacturing (LDM) represents one of the most promising rapid prototyping technologies. It is not only based on rapid deposition manufacturing process but also combined with phase separation process. Besides the controlled macropore size, tissue-engineered scaffold fabricated by LDM has inter-connected micropores in the deposited lines. More importantly, it is a green manufacturing process that involves non-heating liquefying of materials. It has been employed to fabricate tissue-engineered scaffolds for bone, cartilage, blood vessel and nerve tissue regenerations. It is a promising technology in the fabrication of tissue-engineered scaffold similar to ideal scaffold and the design of complex organs. In the current paper, this novel LDM technology is introduced, and its control parameters, biomedical applications and challenges are included and discussed as well. Copyright © 2016 Elsevier B.V. All rights reserved.

US Army Institute of Dental Research Annual Progress Report FY80.

DTIC Science & Technology

1980-10-01

indicates that use of the laser technique does result in increased connectiv tissue regeneration and improved resolution of the periodontal defects...connectiv tissue regeneration and improved resolution of the periodontal defects. Final analysis of histologic data on the use of the neodymium laser for in...and 21 Bone Regeneration in Trnumatic Wounds (Pathology) DA OH 6038 Development of Endodontic Procedures for 22 Military Dentistry ( Oral Biology) DA OK

Regenerated cellulose/wool blend enhanced biomimetic hydroxyapatite mineralization.

PubMed

Salama, Ahmed; El-Sakhawy, Mohamed

2016-11-01

The current article investigates the effect of bioactive cellulose/wool blend on calcium phosphate biomimetic mineralization. Regenerated cellulose/wool blend was prepared by dissolution-regeneration of neat cellulose and natural wool in 1-butyl-3-methyl imidazolium chloride [Bmim][Cl], as a solvent for the two polymers. Crystalline hydroxyapatite nanofibers with a uniform size, shape and dimension were formed after immersing the bioactive blend in simulated body fluid. The cytotoxicity of cellulose/wool/hydroxyapatite was studied using animal fibroblast baby hamster kidney cells (BHK-21) and the result displayed good cytocompatability. This research work presents a green processing method for the development of novel cellulose/wool/hydroxyapatite hybrid materials for tissue engineering applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Possible Mechanism for Denervation Effect on Wound Healing

DTIC Science & Technology

1990-05-23

on wound healing and tissue regener- ation. The system of tissue repair under investigation is the regenerating limb of the axolotl , in which growth...tissues. Before experiments of this nature can be undertaken, axolotl transferlin and antibodies against this factor had to be produced so that...immunoassays could be developed to measure this protein in nerves, regenerating limbs, and other tissues fr m axolotls . These goals were accomplished in the

Augmenting endogenous repair of soft tissues with nanofibre scaffolds

PubMed Central

Snelling, Sarah; Dakin, Stephanie; Carr, Andrew

2018-01-01

As our ability to engineer nanoscale materials has developed we can now influence endogenous cellular processes with increasing precision. Consequently, the use of biomaterials to induce and guide the repair and regeneration of tissues is a rapidly developing area. This review focuses on soft tissue engineering, it will discuss the types of biomaterial scaffolds available before exploring physical, chemical and biological modifications to synthetic scaffolds. We will consider how these properties, in combination, can provide a precise design process, with the potential to meet the requirements of the injured and diseased soft tissue niche. Finally, we frame our discussions within clinical trial design and the regulatory framework, the consideration of which is fundamental to the successful translation of new biomaterials. PMID:29695606

Utilizing collagen membranes for guided tissue regeneration-based root coverage.

PubMed

Wang, Hom-Lay; Modarressi, Marmar; Fu, Jia-Hui

2012-06-01

Gingival recession is a common clinical problem that can result in hypersensitivity, pain, root caries and esthetic concerns. Conventional soft tissue procedures for root coverage require an additional surgical site, thereby causing additional trauma and donor site morbidity. In addition, the grafted tissues heal by repair, with formation of long junctional epithelium with some connective tissue attachment. Guided tissue regeneration-based root coverage was thus developed in an attempt to overcome these limitations while providing comparable clinical results. This paper addresses the biologic foundation of guided tissue regeneration-based root coverage, and describes the indications and contraindications for this technique, as well as the factors that influence outcomes. The step-by-step clinical techniques utilizing collagen membranes are also described. In comparison with conventional soft tissue procedures, the benefits of guided tissue regeneration-based root coverage procedures include new attachment formation, elimination of donor site morbidity, less chair-time, and unlimited availability and uniform thickness of the product. Collagen membranes, in particular, benefit from product biocompatibility with the host, while promoting chemotaxis, hemostasis, and exchange of gas and nutrients. Such characteristics lead to better wound healing by promoting primary wound coverage, angiogenesis, space creation and maintenance, and clot stability. In conclusion, collagen membranes are a reliable alternative for use in root coverage procedures. © 2012 John Wiley & Sons A/S.

Multilayer scaffolds in orthopaedic tissue engineering.

PubMed

Atesok, Kivanc; Doral, M Nedim; Karlsson, Jon; Egol, Kenneth A; Jazrawi, Laith M; Coelho, Paulo G; Martinez, Amaury; Matsumoto, Tomoyuki; Owens, Brett D; Ochi, Mitsuo; Hurwitz, Shepard R; Atala, Anthony; Fu, Freddie H; Lu, Helen H; Rodeo, Scott A

2016-07-01

The purpose of this study was to summarize the recent developments in the field of tissue engineering as they relate to multilayer scaffold designs in musculoskeletal regeneration. Clinical and basic research studies that highlight the current knowledge and potential future applications of the multilayer scaffolds in orthopaedic tissue engineering were evaluated and the best evidence collected. Studies were divided into three main categories based on tissue types and interfaces for which multilayer scaffolds were used to regenerate: bone, osteochondral junction and tendon-to-bone interfaces. In vitro and in vivo studies indicate that the use of stratified scaffolds composed of multiple layers with distinct compositions for regeneration of distinct tissue types within the same scaffold and anatomic location is feasible. This emerging tissue engineering approach has potential applications in regeneration of bone defects, osteochondral lesions and tendon-to-bone interfaces with successful basic research findings that encourage clinical applications. Present data supporting the advantages of the use of multilayer scaffolds as an emerging strategy in musculoskeletal tissue engineering are promising, however, still limited. Positive impacts of the use of next generation scaffolds in orthopaedic tissue engineering can be expected in terms of decreasing the invasiveness of current grafting techniques used for reconstruction of bone and osteochondral defects, and tendon-to-bone interfaces in near future.

3D Printing of Lotus Root-Like Biomimetic Materials for Cell Delivery and Tissue Regeneration.

PubMed

Feng, Chun; Zhang, Wenjie; Deng, Cuijun; Li, Guanglong; Chang, Jiang; Zhang, Zhiyuan; Jiang, Xinquan; Wu, Chengtie

2017-12-01

Biomimetic materials have drawn more and more attention in recent years. Regeneration of large bone defects is still a major clinical challenge. In addition, vascularization plays an important role in the process of large bone regeneration and microchannel structure can induce endothelial cells to form rudimentary vasculature. In recent years, 3D printing scaffolds are major materials for large bone defect repair. However, these traditional 3D scaffolds have low porosity and nonchannel structure, which impede angiogenesis and osteogenesis. In this study, inspired by the microstructure of natural plant lotus root, biomimetic materials with lotus root-like structures are successfully prepared via a modified 3D printing strategy. Compared with traditional 3D materials, these biomimetic materials can significantly improve in vitro cell attachment and proliferation as well as promote in vivo osteogenesis, indicating potential application for cell delivery and bone regeneration.

Latent progenitor cells as potential regulators for tympanic membrane regeneration

NASA Astrophysics Data System (ADS)

Kim, Seung Won; Kim, Jangho; Seonwoo, Hoon; Jang, Kyung-Jin; Kim, Yeon Ju; Lim, Hye Jin; Lim, Ki-Taek; Tian, Chunjie; Chung, Jong Hoon; Choung, Yun-Hoon

2015-06-01

Tympanic membrane (TM) perforation, in particular chronic otitis media, is one of the most common clinical problems in the world and can present with sensorineural healing loss. Here, we explored an approach for TM regeneration where the latent progenitor or stem cells within TM epithelial layers may play an important regulatory role. We showed that potential TM stem cells present highly positive staining for epithelial stem cell markers in all areas of normal TM tissue. Additionally, they are present at high levels in perforated TMs, especially in proximity to the holes, regardless of acute or chronic status, suggesting that TM stem cells may be a potential factor for TM regeneration. Our study suggests that latent TM stem cells could be potential regulators of regeneration, which provides a new insight into this clinically important process and a potential target for new therapies for chronic otitis media and other eardrum injuries.

3D Printing of Lotus Root‐Like Biomimetic Materials for Cell Delivery and Tissue Regeneration

PubMed Central

Feng, Chun; Zhang, Wenjie; Deng, Cuijun; Li, Guanglong; Chang, Jiang; Zhang, Zhiyuan

2017-01-01

Abstract Biomimetic materials have drawn more and more attention in recent years. Regeneration of large bone defects is still a major clinical challenge. In addition, vascularization plays an important role in the process of large bone regeneration and microchannel structure can induce endothelial cells to form rudimentary vasculature. In recent years, 3D printing scaffolds are major materials for large bone defect repair. However, these traditional 3D scaffolds have low porosity and nonchannel structure, which impede angiogenesis and osteogenesis. In this study, inspired by the microstructure of natural plant lotus root, biomimetic materials with lotus root‐like structures are successfully prepared via a modified 3D printing strategy. Compared with traditional 3D materials, these biomimetic materials can significantly improve in vitro cell attachment and proliferation as well as promote in vivo osteogenesis, indicating potential application for cell delivery and bone regeneration. PMID:29270348

A Surgical Device to Study the Efficacy of Bioengineered Skin Substitutes in Mice Wound Healing Models.

PubMed

Jeschke, Marc G; Sadri, Ali-Reza; Belo, Cassandra; Amini-Nik, Saeid

2017-04-01

Due to the poor regenerative capacity of adult mammalian skin, there is a need to develop effective skin substitutes for promoting skin regeneration after a severe wound. However, the complexity of skin biology has made it difficult to enable perfect regeneration of skin. Thus, animal models are being used to test potential skin substitutes. Murine models are valuable but their healing process involves dermal contraction. We have developed a device called a dome that is able to eliminate the contraction effect of rodent skin while simultaneously housing a bioengineered skin graft. The dome comes in two models, which enables researchers to evaluate the cells that contribute in wound healing from neighboring intact tissue during skin healing/regeneration. This protocol simplifies grafting of skin substitutes, eliminates the contraction effect of surrounding skin, and summarizes a simple method for animal surgery for wound healing and skin regeneration studies.

Differential expression of myogenic regulatory genes and Msx-1 during dedifferentiation and redifferentiation of regenerating amphibian limbs.

PubMed

Simon, H G; Nelson, C; Goff, D; Laufer, E; Morgan, B A; Tabin, C

1995-01-01

An amputated limb of an adult urodele amphibian is capable of undergoing regeneration. The new structures form from an undifferentiated mass of cells called the regenerative blastema. The cells of the blastema are believed to derive from differentiated tissues of the adult limb. However, the exact source of these cells and the process by which they undergo dedifferentiation are poorly understood. In order to elucidate the molecular and cellular basis for dedifferentiation we isolated a number of genes which are potential regulators of the process. These include Msx-1, which is believed to support the undifferentiated and proliferative state of cells in the embryonic limb bud; and two members of the myogenic regulatory gene family, MRF-4 and Myf-5, which are expressed in differentiated muscle and regulate muscle-specific gene activity. As anticipated, we find that Msx-1 is strongly up-regulated during the initiation of regeneration. It remains expressed throughout regeneration but is not found in the fully regenerated limb. The myogenic gene MRF-4 has the reverse expression pattern. It is expressed in adult limb muscle, is rapidly shut off in early regenerative blastemas, and is only reexpressed at the completion of regeneration. These kinetics are paralleled by those of a muscle-specific Myosin gene. In contrast Myf-5, a second member of the myogenic gene family, continues to be expressed throughout the regenerative process. Thus, MRF-4 and Myf-5 are likely to play distinct roles during regeneration. MRF-4 may directly regulate muscle phenotype and as such its repression may be a key event in dedifferentiation.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of the tissue reaction to a new bilayered collagen matrix in vivo and its translation to the clinic.

PubMed

Ghanaati, Shahram; Schlee, Markus; Webber, Matthew J; Willershausen, Ines; Barbeck, Mike; Balic, Ela; Görlach, Christoph; Stupp, Samuel I; Sader, Robert A; Kirkpatrick, C James

2011-02-01

This study evaluates a new collagen matrix that is designed with a bilayered structure in order to promote guided tissue regeneration and integration within the host tissue. This material induced a mild tissue reaction when assessed in a murine model and was well integrated within the host tissue, persisting in the implantation bed throughout the in vivo study. A more porous layer was rapidly infiltrated by host mesenchymal cells, while a layer designed to be a barrier allowed cell attachment and host tissue integration, but at the same time remained impermeable to invading cells for the first 30 days of the study. The tissue reaction was favorable, and unlike a typical foreign body response, did not include the presence of multinucleated giant cells, lymphocytes, or granulation tissue. In the context of translation, we show preliminary results from the clinical use of this biomaterial applied to soft tissue regeneration in the treatment of gingival tissue recession and exposed roots of human teeth. Such a condition would greatly benefit from guided tissue regeneration strategies. Our findings demonstrate that this material successfully promoted the ingrowth of gingival tissue and reversed gingival tissue recession. Of particular importance is the fact that the histological evidence from these human studies corroborates our findings in the murine model, with the barrier layer preventing unspecific tissue ingrowth, as the scaffold becomes infiltrated by mesenchymal cells from adjacent tissue into the porous layer. Also in the clinical situation no multinucleated giant cells, no granulation tissue and no evidence of a marked inflammatory response were observed. In conclusion, this bilayered matrix elicits a favorable tissue reaction, demonstrates potential as a barrier for preferential tissue ingrowth, and achieves a desirable therapeutic result when applied in humans for soft tissue regeneration.

The regeneration of thermal wound on mice skin (Mus Musculus) after Q-Switch Nd: YAG laser irradiation for cancer therapy candidate

NASA Astrophysics Data System (ADS)

Apsari, R.; Nahdliyatun, E.; Winarni, D.

2017-09-01

The aims of this study are to investigate the regeneration of mice skin tissue (Mus Musculus) irradiated by Q-Switch Nd: YAG laser and morphological change due to Q-Switch Nd: YAG laser irradiation compared to conventional heating (hairdryer). The 2-3 month of twenty-seven mice were used for experimental animals. Mice were incised in the dorsum by the damage effect of laser energy dose (therapeutic dose) of 29.5 J/cm2 with 10 seconds of exposure time, 10 Hz of repetition rate, and 100 pulses of the given single pulse energy. The mice skin tissue was injuried by hairdryer to get burned effect. Mice were divided into three groups, Group I (control) were not treated by anything, Group II were treated by Q-Switch Nd: YAG laser irradiation and sacrificed on (0, 1, 3, 5) days, and Group III were treated by hairdryer then sacrificed on (0, 1, 3, 5) days. Pathology examination showed that the energy of 29,5 J/cm2 dose produced the hole effect (ablation) through the hypodermic layer caused by optical breakdown and collagen coagulation. Thus, the 60 °C temperature of burn showed coagulation necrosis because piknosis discovered in the injured area. The regeneration process showed that the mice skin tissue's ability to regenerate was irradiated by fast laser because of the focus of Q-Switch Nd: YAG laser. It was showed by the scab releases on third day and completely reepithelialization formation on the fifth day. The collagen fibers distribution was same as normal skin tissue on day 5 and so did angiogenesis. Therefore, Q-Switch Nd: YAG laser can be applied for problems of dermatology medical therapies, especially melasma, nevus of ota and tatto therapy. For skin cancer therapy application, energy dose of unregenerated skin tissue is chosen because the death expected effect is permanent.

High-throughput proteomic characterization of plasma rich in growth factors (PRGF-Endoret)-derived fibrin clot interactome.

PubMed

Anitua, Eduardo; Prado, Roberto; Azkargorta, Mikel; Rodriguez-Suárez, Eva; Iloro, Ibon; Casado-Vela, Juan; Elortza, Felix; Orive, Gorka

2015-11-01

Plasma rich in growth factors (PRGF®-Endoret®) is an autologous technology that contains a set of proteins specifically addressed to wound healing and tissue regeneration. The scaffold formed by using this technology is a clot mainly composed of fibrin protein, forming a three-dimensional (3D) macroscopic network. This biomaterial is easily obtained by biotechnological means from blood and can be used in a range of situations to help wound healing and tissue regeneration. Although the main constituent of this clot is the fibrin scaffold, little is known about other proteins interacting in this clot that may act as adjuvants in the healing process. The aim of this study was to characterize the proteins enclosed by PRGF-Endoret scaffold, using a double-proteomic approach that combines 1D-SDS-PAGE approach followed by LC-MS/MS, and 2-DE followed by MALDI-TOF/TOF. The results presented here provide a description of the catalogue of key proteins in close contact with the fibrin scaffold. The obtained lists of proteins were grouped into families and networks according to gene ontology. Taken together, an enrichment of both proteins and protein families specifically involved in tissue regeneration and wound healing has been found. Copyright © 2013 John Wiley & Sons, Ltd.

Biomimetic 3D tissue printing for soft tissue regeneration.

PubMed

Pati, Falguni; Ha, Dong-Heon; Jang, Jinah; Han, Hyun Ho; Rhie, Jong-Won; Cho, Dong-Woo

2015-09-01

Engineered adipose tissue constructs that are capable of reconstructing soft tissue with adequate volume would be worthwhile in plastic and reconstructive surgery. Tissue printing offers the possibility of fabricating anatomically relevant tissue constructs by delivering suitable matrix materials and living cells. Here, we devise a biomimetic approach for printing adipose tissue constructs employing decellularized adipose tissue (DAT) matrix bioink encapsulating human adipose tissue-derived mesenchymal stem cells (hASCs). We designed and printed precisely-defined and flexible dome-shaped structures with engineered porosity using DAT bioink that facilitated high cell viability over 2 weeks and induced expression of standard adipogenic genes without any supplemented adipogenic factors. The printed DAT constructs expressed adipogenic genes more intensely than did non-printed DAT gel. To evaluate the efficacy of our printed tissue constructs for adipose tissue regeneration, we implanted them subcutaneously in mice. The constructs did not induce chronic inflammation or cytotoxicity postimplantation, but supported positive tissue infiltration, constructive tissue remodeling, and adipose tissue formation. This study demonstrates that direct printing of spatially on-demand customized tissue analogs is a promising approach to soft tissue regeneration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Therapeutic strategy for hair regeneration: Hair cycle activation, niche environment modulation, wound-induced follicle neogenesis and stem cell engineering

PubMed Central

Chueh, Shan-Chang; Lin, Sung-Jan; Chen, Chih-Chiang; Lei, Mingxing; Wang, Ling Mei; Widelitz, Randall B.; Hughes, Michael W.; Jiang, Ting-Xing; Chuong, Cheng Ming

2013-01-01

Introduction There are major new advancements in the fields of stem cell biology, developmental biology, regenerative hair cycling, and tissue engineering. The time is ripe to integrate, translate and apply these findings to tissue engineering and regenerative medicine. Readers will learn about new progress in cellular and molecular aspects of hair follicle development, regeneration and potential therapeutic opportunities these advances may offer. Areas covered Here we use hair follicle formation to illustrate this progress and to identify targets for potential strategies in therapeutics. Hair regeneration is discussed in four different categories. (1) Intra-follicle regeneration (or renewal) is the basic production of hair fibers from hair stem cells and dermal papillae in existing follicles. (2) Chimeric follicles via epithelial-mesenchymal recombination to identify stem cells and signaling centers. (3) Extra-follicular factors including local dermal and systemic factors can modulate the regenerative behavior of hair follicles, and may be relatively easy therapeutic targets. (4) Follicular neogenesis means the de novo formation of new follicles. In addition, scientists are working to engineer hair follicles, which require hair forming competent epidermal cells and hair inducing dermal cells. Expert opinion Ideally self-organizing processes similar to those occurring during embryonic development should be elicited with some help from biomaterials. PMID:23289545

In serum veritas—in serum sanitas? Cell non-autonomous aging compromises differentiation and survival of mesenchymal stromal cells via the oxidative stress pathway

PubMed Central

Geißler, S; Textor, M; Schmidt-Bleek, K; Klein, O; Thiele, M; Ellinghaus, A; Jacobi, D; Ode, A; Perka, C; Dienelt, A; Klose, J; Kasper, G; Duda, G N; Strube, P

2013-01-01

Even tissues capable of complete regeneration, such as bone, show an age-related reduction in their healing capacity. Here, we hypothesized that this decline is primarily due to cell non-autonomous (extrinsic) aging mediated by the systemic environment. We demonstrate that culture of mesenchymal stromal cells (MSCs) in serum from aged Sprague–Dawley rats negatively affects their survival and differentiation ability. Proteome analysis and further cellular investigations strongly suggest that serum from aged animals not only changes expression of proteins related to mitochondria, unfolded protein binding or involved in stress responses, it also significantly enhances intracellular reactive oxygen species production and leads to the accumulation of oxidatively damaged proteins. Conversely, reduction of oxidative stress levels in vitro markedly improved MSC function. These results were validated in an in vivo model of compromised bone healing, which demonstrated significant increase regeneration in aged animals following oral antioxidant administration. These observations indicate the high impact of extrinsic aging on cellular functions and the process of endogenous (bone) regeneration. Thus, addressing the cell environment by, for example, systemic antioxidant treatment is a promising approach to enhance tissue regeneration and to regain cellular function especially in elderly patients. PMID:24357801

Change in Mouse Bone Turnover in Response to Microgravity on RR-1

NASA Technical Reports Server (NTRS)

Cheng-Campbell, Margareth A.; Blaber, Elizabeth A.; Almeida, Eduardo A. C.

2016-01-01

Mechanical unloading during spaceflight is known to adversely affect mammalian physiology. Our previous studies using the Animal Enclosure Module on short duration Shuttle missions enabled us to identify a deficit in stem cell based-tissue regeneration as being a significant concern for long-duration spaceflight. Specifically, we found that mechanical unloading in microgravity resulted in inhibition of differentiation of mesenchymal and hematopoietic stem cells in the bone marrow compartment. Also, we observed overexpression of a cell cycle arrest molecule, CDKN1ap21, in osteoprecursor cells on the bone surface, chondroprogenitors in the articular cartilage, and in myofibers attached to bone tissue. Specifically in bone tissue during both short (15-day) and long (30-day) microgravity experiments, we observed significant loss of bone tissue and structure in both the pelvis and the femur. After 15-days of microgravity on STS-131, pelvic ischium displayed a 6.23 decrease in bone fraction (p0.005) and 11.91 decrease in bone thickness (p0.002). Furthermore, during long-duration spaceflight we observed onset of an accelerated aging-like phenotype and osteoarthritic disease state indicating that stem cells within the bone tissue fail to repair and regenerate tissues in a normal manner, leading to drastic tissue alterations in response to microgravity. The Rodent Research Hardware System provides the capability to investigate these effects during long-duration experiments on the International Space Station. During the Rodent Research-1 mission 10 16-week-old female C57Bl6J mice were exposed to 37-days of microgravity. All flight animals were euthanized and frozen on orbit for future dissection. Ground (n10) and vivarium controls (n10) were housed and processed to match the flight animal timeline. During this study we collected pelvis, femur, and tibia from all animal groups to test the hypothesis that stem cell-based tissue regeneration is significantly altered after 37-days of spaceflight. To do this, we will analyze differences in bone morphometric parameters using MicroCT. The pelvis, femur, and tibia are key in supporting and distributing weight under normal conditions. Therefore, we expect to see altered remodeling in flight animals in response to microgravity with respect to ground controls. In combination with histomorphometry, these results will help elucidate the complex mechanisms underlying bone tissue maintenance and stem cell regeneration.

Changes in Mouse Bone Turnover in Response to Microgravity

NASA Technical Reports Server (NTRS)

Cheng-Campbell, M.; Blaber, E.; Almeida, E.

2016-01-01

Mechanical unloading during spaceflight is known to adversely affect mammalian physiology. Our previous studies using the Animal Enclosure Module on short duration Shuttle missions enabled us to identify a deficit in stem cell based-tissue regeneration as being a significant concern for long-duration spaceflight. Specifically, we found that mechanical unloading in microgravity resulted in inhibition of differentiation of mesenchymal and hematopoietic stem cells in the bone marrow compartment. Also, we observed overexpression of a cell cycle arrest molecule, CDKN1a/p21, in osteoprecursor cells on the bone surface, chondroprogenitors in the articular cartilage, and in myofibers attached to bone tissue. Specifically in bone tissue during both short (15-day) and long (30-day) microgravity experiments, we observed significant loss of bone tissue and structure in both the pelvis and the femur. After 15-days of microgravity on STS-131, pelvic ischium displayed a 6.23% decrease in bone fraction (p=0.005) and 11.91% decrease in bone thickness (p=0.002). Furthermore, during long-duration spaceflight we observed onset of an accelerated aging-like phenotype and osteoarthritic disease state indicating that stem cells within the bone tissue fail to repair and regenerate tissues in a normal manner, leading to drastic tissue alterations in response to microgravity. The Rodent Research Hardware System provides the capability to investigate these effects during long-duration experiments on the International Space Station. During the Rodent Research-1 mission 10 16-week-old female C57Bl/6J mice were exposed to 37-days of microgravity. All flight animals were euthanized and frozen on orbit for future dissection. Ground (n=10) and vivarium controls (n=10) were housed and processed to match the flight animal timeline. During this study we collected pelvis, femur, and tibia from all animal groups to test the hypothesis that stem cell-based tissue regeneration is significantly altered after 37-days of spaceflight. To do this, we will analyze differences in bone morphometric parameters using MicroCT. The pelvis, femur, and tibia are key in supporting and distributing weight under normal conditions. Therefore, we expect to see altered remodeling in flight animals in response to microgravity with respect to ground controls. In combination with histomorphometry, these results will help elucidate the complex mechanisms underlying bone tissue maintenance and stem cell regeneration.

Resolving Heart Regeneration by Replacement Histone Profiling.

PubMed

Goldman, Joseph Aaron; Kuzu, Guray; Lee, Nutishia; Karasik, Jaclyn; Gemberling, Matthew; Foglia, Matthew J; Karra, Ravi; Dickson, Amy L; Sun, Fei; Tolstorukov, Michael Y; Poss, Kenneth D

2017-02-27

Chromatin regulation is a principal mechanism governing animal development, yet it is unclear to what extent structural changes in chromatin underlie tissue regeneration. Non-mammalian vertebrates such as zebrafish activate cardiomyocyte (CM) division after tissue damage to regenerate lost heart muscle. Here, we generated transgenic zebrafish expressing a biotinylatable H3.3 histone variant in CMs and derived cell-type-specific profiles of histone replacement. We identified an emerging program of putative enhancers that revise H3.3 occupancy during regeneration, overlaid upon a genome-wide reduction of H3.3 from promoters. In transgenic reporter lines, H3.3-enriched elements directed gene expression in subpopulations of CMs. Other elements increased H3.3 enrichment and displayed enhancer activity in settings of injury- and/or Neuregulin1-elicited CM proliferation. Dozens of consensus sequence motifs containing predicted transcription factor binding sites were enriched in genomic regions with regeneration-responsive H3.3 occupancy. Thus, cell-type-specific regulatory programs of tissue regeneration can be revealed by genome-wide H3.3 profiling. Copyright © 2017 Elsevier Inc. All rights reserved.

Aging changes in organs - tissue - cells

MedlinePlus

... usually occurs to compensate for a loss of cells. It allows some organs and tissues to regenerate, including the skin, lining of the intestines, liver, and bone marrow. The liver is especially good at regeneration. It can replace up to 70% of its ...

Patient-specific cardiovascular progenitor cells derived from integration-free induced pluripotent stem cells for vascular tissue regeneration.

PubMed

Hu, Jiang; Wang, Yongyu; Jiao, Jiao; Liu, Zhongning; Zhao, Chao; Zhou, Zhou; Zhang, Zhanpeng; Forde, Kaitlynn; Wang, Lunchang; Wang, Jiangang; Baylink, David J; Zhang, Xiao-Bing; Gao, Shaorong; Yang, Bo; Chen, Y Eugene; Ma, Peter X

2015-12-01

Tissue-engineered blood vessels (TEBVs) are promising in regenerating a live vascular replacement. However, the vascular cell source is limited, and it is crucial to develop a scaffold that accommodates new type of vascular progenitor cells and facilitates in vivo lineage specification of the cells into functional vascular smooth muscle cells (VSMCs) to regenerate vascular tissue. In the present study, integration-free human induced pluripotent stem cells (hiPSCs) were established from patient peripheral blood mononuclear cells through episomal vector nucleofection of reprogramming factors. The established hiPSCs were then induced into mesoderm-originated cardiovascular progenitor cells (CVPCs) with a highly efficient directed lineage specification method. The derived CVPCs were demonstrated to be able to differentiate into functional VSMCs. Subcutaneous implantation of CVPCs seeded on macroporous nanofibrous poly(l-lactide) scaffolds led to in vivo VSMC lineage specification and matrix deposition inside the scaffolds. In summary, we established integration-free patient-specific hiPSCs from peripheral blood mononuclear cells, derived CVPCs through directed lineage specification, and developed an advanced scaffold for these progenitor cells to further differentiate in vivo into VSMCs and regenerate vascular tissue in a subcutaneous implantation model. This study has established an efficient patient-specific approach towards in vivo regeneration of vascular tissue. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rapid Genetic Analysis of Epithelial-Mesenchymal Signaling During Hair Regeneration

PubMed Central

Zhen, Hanson H.; Oro, Anthony E.

2013-01-01

Hair follicle morphogenesis, a complex process requiring interaction between epithelia-derived keratinocytes and the underlying mesenchyme, is an attractive model system to study organ development and tissue-specific signaling. Although hair follicle development is genetically tractable, fast and reproducible analysis of factors essential for this process remains a challenge. Here we describe a procedure to generate targeted overexpression or shRNA-mediated knockdown of factors using lentivirus in a tissue-specific manner. Using a modified version of a hair regeneration model 5, 6, 11, we can achieve robust gain- or loss-of-function analysis in primary mouse keratinocytes or dermal cells to facilitate study of epithelial-mesenchymal signaling pathways that lead to hair follicle morphogenesis. We describe how to isolate fresh primary mouse keratinocytes and dermal cells, which contain dermal papilla cells and their precursors, deliver lentivirus containing either shRNA or cDNA to one of the cell populations, and combine the cells to generate fully formed hair follicles on the backs of nude mice. This approach allows analysis of tissue-specific factors required to generate hair follicles within three weeks and provides a fast and convenient companion to existing genetic models. PMID:23486463

Unit cell-based computer-aided manufacturing system for tissue engineering.

PubMed

Kang, Hyun-Wook; Park, Jeong Hun; Kang, Tae-Yun; Seol, Young-Joon; Cho, Dong-Woo

2012-03-01

Scaffolds play an important role in the regeneration of artificial tissues or organs. A scaffold is a porous structure with a micro-scale inner architecture in the range of several to several hundreds of micrometers. Therefore, computer-aided construction of scaffolds should provide sophisticated functionality for porous structure design and a tool path generation strategy that can achieve micro-scale architecture. In this study, a new unit cell-based computer-aided manufacturing (CAM) system was developed for the automated design and fabrication of a porous structure with micro-scale inner architecture that can be applied to composite tissue regeneration. The CAM system was developed by first defining a data structure for the computing process of a unit cell representing a single pore structure. Next, an algorithm and software were developed and applied to construct porous structures with a single or multiple pore design using solid freeform fabrication technology and a 3D tooth/spine computer-aided design model. We showed that this system is quite feasible for the design and fabrication of a scaffold for tissue engineering.

Concise Review: Biomimetic Functionalization of Biomaterials to Stimulate the Endogenous Healing Process of Cartilage and Bone Tissue.

PubMed

Taraballi, Francesca; Bauza, Guillermo; McCulloch, Patrick; Harris, Josh; Tasciotti, Ennio

2017-12-01

Musculoskeletal reconstruction is an ongoing challenge for surgeons as it is required for one out of five patients undergoing surgery. In the past three decades, through the close collaboration between clinicians and basic scientists, several regenerative strategies have been proposed. These have emerged from interdisciplinary approaches that bridge tissue engineering with material science, physiology, and cell biology. The paradigm behind tissue engineering is to achieve regeneration and functional recovery using stem cells, bioactive molecules, or supporting materials. Although plenty of preclinical solutions for bone and cartilage have been presented, only a few platforms have been able to move from the bench to the bedside. In this review, we highlight the limitations of musculoskeletal regeneration and summarize the most relevant acellular tissue engineering approaches. We focus on the strategies that could be most effectively translate in clinical practice and reflect on contemporary and cutting-edge regenerative strategies in surgery. Stem Cells Translational Medicine 2017;6:2186-2196. © 2017 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

Combined antibacterial/tissue regeneration response in thermal burns promoted by functional chitosan/silver nanocomposites.

PubMed

Luna-Hernández, E; Cruz-Soto, M E; Padilla-Vaca, F; Mauricio-Sánchez, R A; Ramirez-Wong, D; Muñoz, R; Granados-López, L; Ovalle-Flores, L R; Menchaca-Arredondo, J L; Hernández-Rangel, A; Prokhorov, E; García-Rivas, J L; España-Sánchez, B L; Luna-Bárcenas, G

2017-12-01

We report the combined antibacterial/tissue regeneration responses to thermal burns promoted by functional chitosan/silver nanocomposites (CS/nAg) with ultralow silver content (0.018wt.%, 7-30nm). Our approach allows one to produce CS/nAg nanocomposites without silver nanoparticles (nAg) agglomeration, with bactericide potency higher than 1wt.% of nAg (ca. 10nm) content and, promoting the healing process in controlled thermal burns. CS/nAg films exhibit high antibacterial activity against S. aureus and P. aeruginosa after 1.5h of incubation, demonstrating the bacterial penetration into hydrated films and their interaction with nAg. Additionally, exceptional healing of induced thermal burns was obtained by increasing myofibroblasts, collagen remodeling, and blood vessel neoformation. These factors are associated with epiderma regeneration after 7days of treatment with no nAg release. Our results corroborate the controlled synthesis of nAg embedded in CS matrix with combined antibacterial/biocompatibility properties aiming to produce functional nanocomposites with potential use in wound dressing and health care applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of mesenchymal stem cells on stomach tissue engineering using small intestinal submucosa.

PubMed

Nakatsu, Hiroki; Ueno, Tomio; Oga, Atsunori; Nakao, Mitsuhiro; Nishimura, Taku; Kobayashi, Sei; Oka, Masaaki

2015-03-01

Small intestinal submucosa (SIS) is a biodegradable collagen-rich matrix containing functional growth factors. We have previously reported encouraging outcomes for regeneration of an artificial defect in the rodent stomach using SIS grafts, although the muscular layer was diminutive. In this study, we investigated the feasibility of SIS in conjunction with mesenchymal stem cells (MSCs) for regeneration of the gastrointestinal tract. MSCs from the bone marrow of green fluorescence protein (GFP)-transgenic Sprague-Dawley (SD) rats were isolated and expanded ex vivo. A 1 cm whole-layer stomach defect in SD rats was repaired using: a plain SIS graft without MSCs (group 1, control); a plain SIS graft followed by intravenous injection of MSCs (group 2); a SIS graft co-cultured with MSCs (group 3); or a SIS sandwich containing an MSC sheet (group 4). Pharmacological, electrophysiological and immunohistochemical examination was performed to evaluate the regenerated stomach tissue. Contractility in response to a muscarinic receptor agonist, a nitric oxide precursor or electrical field stimulation was observed in all groups. SIS grafts seeded with MSCs (groups 3 and 4) appeared to support improved regeneration compared with SIS grafts not seeded with MSCs (groups 1 and 2), by enabling the development of well-structured smooth muscle layers of significantly increased length. GFP expression was detected in the regenerated interstitial tissue, with fibroblast-like cells in the seeded-SIS groups. SIS potently induced pharmacological and electrophysiological regeneration of the digestive tract, and seeded MSCs provided an enriched environment that supported tissue regeneration by the SIS graft in the engineered stomach. © 2013 The Authors. Journal of Tissue Engineering and Regenerative Medicine published by John Wiley & Sons, Ltd.

Identification of a Peripheral Nerve Neurite Growth-Promoting Activity by Development and Use of an in vitro Bioassay

NASA Astrophysics Data System (ADS)

Sandrock, Alfred W.; Matthew, William D.

1987-10-01

The effective regeneration of severed neuronal axons in the peripheral nerves of adult mammals may be explained by the presence of molecules in situ that promote the effective elongation of neurites. The absence of such molecules in the central nervous system of these animals may underlie the relative inability of axons to regenerate in this tissue after injury. In an effort to identify neurite growth-promoting molecules in tissues that support effective axonal regeneration, we have developed an in vitro bioassay that is sensitive to substrate-bound factors of peripheral nerve that influence the growth of neurites. In this assay, neonatal rat superior cervical ganglion explants are placed on longitudinal cryostat sections of fresh-frozen sciatic nerve, and the regrowing axons are visualized by catecholamine histofluorescence. Axons are found to regenerate effectively over sciatic nerve tissue sections. When ganglia are similarly explanted onto cryostat sections of adult rat central nervous system tissue, however, axonal regeneration is virtually absent. We have begun to identify the molecules in peripheral nerve that promote effective axonal regeneration by examining the effect of antibodies that interfere with the activity of previously described neurite growth-promoting factors. Axonal elongation over sciatic nerve tissue was found to be sensitive to the inhibitory effects of INO (for inhibitor of neurite outgrowth), a monoclonal antibody that recognizes and inhibits a neurite growth-promoting activity from PC-12 cell-conditioned medium. The INO antigen appears to be a molecular complex of laminin and heparan sulfate proteoglycan. In contrast, a rabbit antiserum that recognizes laminin purified from mouse Engelbreth-Holm-Swarm (EHS) sarcoma, stains the Schwann cell basal lamina of peripheral nerve, and inhibits neurite growth over purified laminin substrata has no detectable effect on the rate of axonal regeneration in our assay.

Influence of mesenchymal stem cells on stomach tissue engineering using small intestinal submucosa

PubMed Central

Nakatsu, Hiroki; Ueno, Tomio; Oga, Atsunori; Nakao, Mitsuhiro; Nishimura, Taku; Kobayashi, Sei; Oka, Masaaki

2015-01-01

Small intestinal submucosa (SIS) is a biodegradable collagen-rich matrix containing functional growth factors. We have previously reported encouraging outcomes for regeneration of an artificial defect in the rodent stomach using SIS grafts, although the muscular layer was diminutive. In this study, we investigated the feasibility of SIS in conjunction with mesenchymal stem cells (MSCs) for regeneration of the gastrointestinal tract. MSCs from the bone marrow of green fluorescence protein (GFP)-transgenic Sprague–Dawley (SD) rats were isolated and expanded ex vivo. A 1 cm whole-layer stomach defect in SD rats was repaired using: a plain SIS graft without MSCs (group 1, control); a plain SIS graft followed by intravenous injection of MSCs (group 2); a SIS graft co-cultured with MSCs (group 3); or a SIS sandwich containing an MSC sheet (group 4). Pharmacological, electrophysiological and immunohistochemical examination was performed to evaluate the regenerated stomach tissue. Contractility in response to a muscarinic receptor agonist, a nitric oxide precursor or electrical field stimulation was observed in all groups. SIS grafts seeded with MSCs (groups 3 and 4) appeared to support improved regeneration compared with SIS grafts not seeded with MSCs (groups 1 and 2), by enabling the development of well-structured smooth muscle layers of significantly increased length. GFP expression was detected in the regenerated interstitial tissue, with fibroblast-like cells in the seeded-SIS groups. SIS potently induced pharmacological and electrophysiological regeneration of the digestive tract, and seeded MSCs provided an enriched environment that supported tissue regeneration by the SIS graft in the engineered stomach. © 2013 The Authors. Journal of Tissue Engineering and Regenerative Medicine published by John Wiley & Sons, Ltd. PMID:23913876

[11C]choline uptake in regenerating liver after partial hepatectomy or CCl4-administration.

PubMed

Sasaki, Toru

2004-02-01

To characterize [methyl-(11)C]choline ([(11)C]choline) as an oncologic PET radiopharmaceutical, [(11)C]choline uptake in regenerating livers after partial hepatectomy as a model of typical proliferating tissue and after CCl(4) insult as that of proliferating tissue with inflammation, was studied in rats. [(11)C]Choline, [(18)F]2-fluoro-2-deoxy-D-glucose ([(18)F]FDG) and [2-(14)C]thymidine ([(14)C]TdR) uptake was studied in regenerating rat liver after 70% partial hepatectomy or CCl(4)-administration. [(11)C]Choline uptake in regenerating liver after partial hepatectomy was significantly increased with [(14)C]TdR uptake as a marker of DNA synthesis at 18 hours after surgery. On the other hand, the uptake was not accelerated by CCl(4)-administration, though it significantly increased [(14)C]TdR uptake. There were no differences of [(11)C]choline uptake acceleration following partial hepatectomy among the three parts of the regenerating liver. [(18)F]FDG uptake was accelerated in the regenerating liver on either partial hepatectomy or CCl(4)-administration. The magnitude of the increase in [(18)F]FDG uptake in the regenerating liver induced by partial hepatectomy was greater than that for [(11)C]choline. [(11)C]Choline uptake in the liver was accelerated by partial hepatectomy, but not by CCl(4)-administration. This might be expected given that the differentiation between proliferating tissues such as tumor and inflammatory tissue was possible by [(11)C]choline-PET.

Knockdown of the coenzyme Q synthesis gene Smed-dlp1 affects planarian regeneration and tissue homeostasis

PubMed Central

Shiobara, Yumiko; Harada, Chiaki; Shiota, Takeshi; Sakamoto, Kimitoshi; Kita, Kiyoshi; Tanaka, Saeko; Tabata, Kenta; Sekie, Kiyoteru; Yamamoto, Yorihiro; Sugiyama, Tomoyasu

2015-01-01

The freshwater planarian is a model organism used to study tissue regeneration that occupies an important position among multicellular organisms. Planarian genomic databases have led to the identification of genes that are required for regeneration, with implications for their roles in its underlying mechanism. Coenzyme Q (CoQ) is a fundamental lipophilic molecule that is synthesized and expressed in every cell of every organism. Furthermore, CoQ levels affect development, life span, disease and aging in nematodes and mice. Because CoQ can be ingested in food, it has been used in preventive nutrition. In this study, we investigated the role of CoQ in planarian regeneration. Planarians synthesize both CoQ9 and rhodoquinone 9 (RQ9). Knockdown of Smed-dlp1, a trans-prenyltransferase gene that encodes an enzyme that synthesizes the CoQ side chain, led to a decrease in CoQ9 and RQ9 levels. However, ATP levels did not consistently decrease in these animals. Knockdown animals exhibited tissue regression and curling. The number of mitotic cells decreased in Smed-dlp1 (RNAi) animals. These results suggested a failure in physiological cell turnover and stem cell function. Accordingly, regenerating planarians died from lysis or exhibited delayed regeneration. Interestingly, the observed phenotypes were partially rescued by ingesting food supplemented with α-tocopherol. Taken together, our results suggest that oxidative stress induced by reduced CoQ9 levels affects planarian regeneration and tissue homeostasis. PMID:26516985

Surgical Ablation Assay for Studying Eye Regeneration in Planarians.

PubMed

Morton, Jacob M; Saad, Marwa A; Beane, Wendy S

2017-04-14

In the study of adult stem cells and regenerative mechanisms, planarian flatworms are a staple in vivo model system. This is due in large part to their abundant pluripotent stem cell population and ability to regenerate all cell and tissue types after injuries that would be catastrophic for most animals. Recently, planarians have gained popularity as a model for eye regeneration. Their ability to regenerate the entire eye (comprised of two tissue types: pigment cells and photoreceptors) allows for the dissection of the mechanisms regulating visual system regeneration. Eye ablation has several advantages over other techniques (such as decapitation or hole punch) for examining eye-specific pathways and mechanisms, the most important of which is that regeneration is largely restricted to eye tissues alone. The purpose of this video article is to demonstrate how to reliably remove the planarian optic cup without disturbing the brain or surrounding tissues. The handling of worms and maintenance of an established colony is also described. This technique uses a 31 G, 5/16-inch insulin needle to surgically scoop out the optic cup of planarians immobilized on a cold plate. This method encompasses both single and double eye ablation, with eyes regenerating within 1-2 weeks, allowing for a wide range of applications. In particular, this ablation technique can be easily combined with pharmacological and genetic (RNA interference) screens for a better understanding of regenerative mechanisms and their evolution, eye stem cells and their maintenance, and phototaxic behavioral responses and their neurological basis.

GH indirectly enhances the regeneration of transgenic zebrafish fins through IGF2a and IGF2b.

PubMed

Nornberg, Bruna Félix; Almeida, Daniela Volcan; Figueiredo, Márcio Azevedo; Marins, Luis Fernando

2016-10-01

The somatotropic axis, composed essentially of the growth hormone (GH) and insulin-like growth factors (IGFs), is the main regulator of somatic growth in vertebrates. However, these protein hormones are also involved in various other major physiological processes. Although the importance of IGFs in mechanisms involving tissue regeneration has already been established, little is known regarding the direct effects of GH in these processes. In this study, we used a transgenic zebrafish (Danio rerio) model, which overexpresses GH from the beta-actin constitutive promoter. The regenerative ability of the caudal fin was assessed after repeated amputations, as well as the expression of genes related to the GH/IGF axis. The results revealed that GH overexpression increased the regenerated area of the caudal fin in transgenic fish after the second amputation. Transgenic fish also presented a decrease in gene expression of the GH receptor (ghrb), in opposition to the increased expression of the IGF1 receptors (igf1ra and igf1rb). These results suggest that transgenic fish have a higher sensitivity to IGFs than to GH during fin regeneration. With respect to the different IGFs produced locally, a decrease in igf1a expression and a significant increase in both igf2a and igf2b expression was observed, suggesting that igf1a is not directly involved in fin regeneration. Overall, the results revealed that excess GH enhances fin regeneration in zebrafish through igf2a and igf2b expression, acting indirectly on this major physiological process.

Comparison of ADM and Connective Tissue Graft as the Membrane in Class II Furcation Defect Regeneration: A Randomized Clinical Trial

PubMed Central

Esfahanian, Vahid; Farhad, Shirin; Sadighi Shamami, Mehrnaz

2014-01-01

Background and aims. Furcally-involved teeth present unique challenges to the success of periodontal therapy and influence treatment outcomes. This study aimed to assess to compare use of ADM and connective tissue membrane in class II furcation defect regeneration. Materials and methods. 10 patient with 2 bilaterally class II furcation defects in first and/or second maxilla or man-dibular molar without interproximal furcation involvement, were selected. Four weeks after initial phase of treatment, before and thorough the surgery pocket depth (PD), clinical attachment level to stent (CAL-S), free gingival margin to stent(FGM-S) , crestal bone to stent (Crest-S), horizontal defect depth to stent (HDD-S) and vertical defect depth to stent (VDD-S) and crestal bone to defect depth measured from stent margin. Thereafter, one side randomly treated using connective tissue and DFDBA (study group) and opposite side received ADM and DFDBA (control group). After 6 months, soft and hard tissue parameters measured again in re-entry. Results. Both groups presented improvements after therapies (P & 0.05). No inter-group differences were seen in PD re-duction (P = 0.275), CAL gain (P = 0.156), free gingival margin (P = 0.146), crest of the bone (P = 0.248), reduction in horizontal defects depth (P = 0.139) and reduction in vertical defects depth (P = 0.149). Conclusion. Both treatments modalities have potential of regeneration without any adverse effect on healing process. Connective tissue grafts did not have significant higher bone fill compared to that of ADM. PMID:25093054

Treatment outcomes of ligature-induced recession in the dog model using guided tissue regeneration or coronally positioned flap procedures.

PubMed

Papageorgiou, Athanasios; Vouros, Ioannis; Konstantinidis, Antonios

2009-04-01

The aims of the study were: (1) to determine the quality of the hard and soft tissues formed in segments treated with coronally positioned flaps alone (CPF group) or combined with a polylactic acid resorbable membrane (guided tissue regeneration--GTR group) in wide type defects (canine teeth), and (2) to evaluate the behaviour of the newly regenerated tissues to an experimentally induced inflammation initiated by microbial plaque at the submarginal level in recession type defects (premolar teeth). The randomized block design was used in the study, with each dog receiving both treatments (GTR and CPF). Gingival recession defects were surgically created in the 2nd and 4th mandibular premolars and, after 10 weeks, also in the maxillary canines of three dogs. The defects in the premolar area were created earlier than the defects in the canine teeth so that both areas would be ready for biopsy at the same time. Two months after the creation of the defects the exposed roots in the control group of teeth were surgically covered with coronally positioned flaps only (CPF group), and in the test group of teeth a coronally positioned flap was used in combination with a resorbable membrane (GTR group). In the premolar teeth only, after a healing period of five months, cotton ligatures were placed intrasulcularly and these areas were left without plaque control for 10 weeks. Following this, biopsies were taken from the canines and the premolars in order to examine (1) the quality of the hard and soft tissues formed after five months of healing in the canine teeth and (2) the response of the newly formed tissues to microbial accumulation induced by the subgingival ligature placement. In the wide defects of the canine teeth, the use of the membrane produced a mean new attachment formation of 44%, while the repositioned flap technique produced 22% new attachment. The regeneration of bone was limited to the apical area for both techniques and amounted to 15% and 10%, respectively. In the narrow defects of the premolars both techniques produced comparable mean root coverage percentages. The inflammatory conditions created in the study led to a comparable loss of mean clinical attachment and an increase in tissue recession and the extent of the inflammatory process for both groups. The use of resorbable membranes for the treatment of wide recession type defects in the canine teeth (GTR group) produced significantly better clinical results, with higher mean root coverage and increased regenerative capacity of the periodontal tissues, compared with the coronally positioned flap technique (CPF group). Additionally, the regenerated tissues created after the use of both techniques in narrow recession defects (premolar teeth) demonstrated comparable resistance to the microbial accumulation conditions created.

The Role of a Platelet Lysate-Based Compartmentalized System as a Carrier of Cells and Platelet-Origin Cytokines for Periodontal Tissue Regeneration.

PubMed

Babo, Pedro S; Cai, Xinjie; Plachokova, Adelina S; Reis, Rui L; Jansen, John A; Gomes, Manuela E; Walboomers, X Frank

2016-10-01

Currently available clinical therapies are not capable to regenerate tissues that are lost by periodontitis. Tissue engineering can be applied as a strategy to regenerate reliably the tissues and function of damaged periodontium. A prerequisite for this regeneration is the colonization of the defect with the adequate cell populations. In this study, we proposed a bilayered system composed of (1) a platelet lysate (PL)-based construct produced by crosslinking of PL proteins with genipin (gPL) for the delivery of rat periodontal ligament cells (rat-PDLCs); combined with (2) an injectable composite consisting of calcium phosphate cement incorporated with PL-loaded poly(d, l-lactic-co-glycolic acid) microspheres. This system was expected to promote periodontal regeneration by the delivery of adequate progenitor cells and providing a stable system enriched with adequate cytokines and growth factors for the orchestration of tissue regrowth in periodontal defects. The bilayered system was tested in a three-wall intrabony defect in rats and the healing of periodontal tissue was assessed 6 weeks after surgery. Results showed that the bilayered system was able to promote the regrowth of functional periodontal tissues, both with (cells + gPL) and without the loading of PDLCs (gPL). Significant connective tissue attachment (45.0 ± 15.0% and 64.0 ± 15.0% for gPL and cells + gPL group, respectively) and new bone area (33.8 ± 21% and 21.3 ± 3% for gPL and cells + gPL group, respectively) were observed. Nevertheless, rat PDLCs delivered with gPL construct in the defect area were hardly visible 6 weeks after surgery and did not contribute for the regeneration of new periodontal tissue. Overall, our findings show that the bilayered system promotes the stabilization of PL proteins on the root surface and has a positive effect in the repair of periodontal tissues both in quality and in quantity.

Micro-RNAs in regenerating lungs: an integrative systems biology analysis of murine influenza pneumonia.

PubMed

Tan, Kai Sen; Choi, Hyungwon; Jiang, Xiaoou; Yin, Lu; Seet, Ju Ee; Patzel, Volker; Engelward, Bevin P; Chow, Vincent T

2014-07-11

Tissue regeneration in the lungs is gaining increasing interest as a potential influenza management strategy. In this study, we explored the role of microRNAs, short non-coding RNAs involved in post-transcriptional regulation, during pulmonary regeneration after influenza infection. We profiled miRNA and mRNA expression levels following lung injury and tissue regeneration using a murine influenza pneumonia model. BALB/c mice were infected with a sub-lethal dose of influenza A/PR/8(H1N1) virus, and their lungs were harvested at 7 and 15 days post-infection to evaluate the expression of ~300 miRNAs along with ~36,000 genes using microarrays. A global network was constructed between differentially expressed miRNAs and their potential target genes with particular focus on the pulmonary repair and regeneration processes to elucidate the regulatory role of miRNAs in the lung repair pathways. The miRNA arrays revealed a global down-regulation of miRNAs. TargetScan analyses also revealed specific miRNAs highly involved in targeting relevant gene functions in repair such as miR-290 and miR-505 at 7 dpi; and let-7, miR-21 and miR-30 at 15 dpi. The significantly differentially regulated miRNAs are implicated in the activation or suppression of cellular proliferation and stem cell maintenance, which are required during the repair of the damaged lungs. These findings provide opportunities in the development of novel repair strategies in influenza-induced pulmonary injury.

Denervation affects regenerative responses in MRL/MpJ and repair in C57BL/6 ear wounds

PubMed Central

Buckley, Gemma; Wong, Jason; Metcalfe, Anthony D; Ferguson, Mark W J

2012-01-01

The MRL/MpJ mouse displays the rare ability amongst mammals to heal injured ear tissue without scarring. Numerous studies have shown that the formation of a blastema-like structure leads to subsequent tissue regeneration in this model, indicating many parallels with amphibian limb regeneration and mammalian embryogenesis. We have recently shown that the MRL/MpJ mouse also possesses an enhanced capacity for peripheral nerve regeneration within the ear wound. Indeed, nerves are vital for the initial phase of blastema formation in the amphibian limb. In this study we investigated the capacity for wound regeneration in a denervated ear. The left ears of MRL/MpJ mice and C57BL/6 (a control strain known to have a poorer regenerative capacity) were surgically denervated at the base via an incision and nerve transection, immediately followed by a 2-mm ear punch wound. Immunohistochemical analysis showed a lack of neurofilament expression in the denervated ear wound. Histology revealed that denervation prevented blastema formation and chrondrogenesis, and also severely hindered normal healing, with disrupted re-epithelialisation, increasing wound size and progressive necrosis towards the ear tip. Denervation of the ear obliterated the regenerative capacity of the MRL/MpJ mouse, and also had a severe negative effect on the ear wound repair mechanisms of the C57BL/6 strain. These data suggest that innervation may be important not only for regeneration but also for normal wound repair processes. PMID:22066944

Bone tissue engineering: state of the art and future trends.

PubMed

Salgado, António J; Coutinho, Olga P; Reis, Rui L

2004-08-09

Although several major progresses have been introduced in the field of bone regenerative medicine during the years, current therapies, such as bone grafts, still have many limitations. Moreover, and in spite of the fact that material science technology has resulted in clear improvements in the field of bone substitution medicine, no adequate bone substitute has been developed and hence large bone defects/injuries still represent a major challenge for orthopaedic and reconstructive surgeons. It is in this context that TE has been emerging as a valid approach to the current therapies for bone regeneration/substitution. In contrast to classic biomaterial approach, TE is based on the understanding of tissue formation and regeneration, and aims to induce new functional tissues, rather than just to implant new spare parts. The present review pretends to give an exhaustive overview on all components needed for making bone tissue engineering a successful therapy. It begins by giving the reader a brief background on bone biology, followed by an exhaustive description of all the relevant components on bone TE, going from materials to scaffolds and from cells to tissue engineering strategies, that will lead to "engineered" bone. Scaffolds processed by using a methodology based on extrusion with blowing agents.

Generation and Assessment of Functional Biomaterial Scaffolds for Applications in Cardiovascular Tissue Engineering and Regenerative Medicine.

PubMed

Hinderer, Svenja; Brauchle, Eva; Schenke-Layland, Katja

2015-11-18

Current clinically applicable tissue and organ replacement therapies are limited in the field of cardiovascular regenerative medicine. The available options do not regenerate damaged tissues and organs, and, in the majority of the cases, show insufficient restoration of tissue function. To date, anticoagulant drug-free heart valve replacements or growing valves for pediatric patients, hemocompatible and thrombus-free vascular substitutes that are smaller than 6 mm, and stem cell-recruiting delivery systems that induce myocardial regeneration are still only visions of researchers and medical professionals worldwide and far from being the standard of clinical treatment. The design of functional off-the-shelf biomaterials as well as automatable and up-scalable biomaterial processing methods are the focus of current research endeavors and of great interest for fields of tissue engineering and regenerative medicine. Here, various approaches that aim to overcome the current limitations are reviewed, focusing on biomaterials design and generation methods for myocardium, heart valves, and blood vessels. Furthermore, novel contact- and marker-free biomaterial and extracellular matrix assessment methods are highlighted. © 2015 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The expression of embryonic primary mesenchyme genes of the sea urchin, Strongylocentrotus purpuratus, in the adult skeletogenic tissues of this and other species of echinoderms.

PubMed

Drager, B J; Harkey, M A; Iwata, M; Whiteley, A H

1989-05-01

Adult tissues of the sea urchin, Strongylocentrotus purpuratus, were analyzed for the products of a set of genes whose expression, in the embryo, is restricted to the skeletogenic primary mesenchyme (PM). Three embryonic PM-specific mRNAs were found to be abundant in adult skeletal tissues (test and lantern), but not in a variety of soft tissues. Homologous mRNAs were also found in skeletal tissues of the congeneric sea urchin, S. droebachiensis, as well as a more distantly related echinoid, Dendraster excentricus, and an asteroid, Evasterias troschellii. The distributions of two of these RNAs were analyzed in regenerating spines of adult S. purpuratus using in situ hybridization. These gene products were localized primarily in the calcoblasts that accumulated at the regeneration site. In nonregenerating spines SpLM 18 RNAs, the most abundant of these gene products, were localized in a small population of noncalcoblast cells scattered through the spine shaft, and were absent from calcoblasts. These observations suggest that a program of gene expression associated with the process of calcification is conserved both developmentally through the period of metamorphosis and evolutionarily among the echinoderms.

Study Progress on Tissue Culture of Maize Mature Embryo

NASA Astrophysics Data System (ADS)

Wang, Hongzhen; Cheng, Jun; Cheng, Yanping; Zhou, Xioafu

It has been paid more and more attention on maize tissue culture as it is a basic work in maize genetic transformation, especially huge breakthrough has been made in maize tissue culture utilizing mature embryos as explants in the recent years. This paper reviewed the study progress on maize tissue culture and plant regeneration utilizing mature embryos as explants from callus induction, subculture, plant regeneration and browning reduction and so on.

Synthetic Bone Substitute Engineered with Amniotic Epithelial Cells Enhances Bone Regeneration after Maxillary Sinus Augmentation

PubMed Central

Barboni, Barbara; Mangano, Carlo; Valbonetti, Luca; Marruchella, Giuseppe; Berardinelli, Paolo; Martelli, Alessandra; Muttini, Aurelio; Mauro, Annunziata; Bedini, Rossella; Turriani, Maura; Pecci, Raffaella; Nardinocchi, Delia; Zizzari, Vincenzo Luca; Tetè, Stefano; Piattelli, Adriano; Mattioli, Mauro

2013-01-01

Background Evidence has been provided that a cell-based therapy combined with the use of bioactive materials may significantly improve bone regeneration prior to dental implant, although the identification of an ideal source of progenitor/stem cells remains to be determined. Aim In the present research, the bone regenerative property of an emerging source of progenitor cells, the amniotic epithelial cells (AEC), loaded on a calcium-phosphate synthetic bone substitute, made by direct rapid prototyping (rPT) technique, was evaluated in an animal study. Material And Methods Two blocks of synthetic bone substitute (∼0.14 cm3), alone or engineered with 1×106 ovine AEC (oAEC), were grafted bilaterally into maxillary sinuses of six adult sheep, an animal model chosen for its high translational value in dentistry. The sheep were then randomly divided into two groups and sacrificed at 45 and 90 days post implantation (p.i.). Tissue regeneration was evaluated in the sinus explants by micro-computer tomography (micro-CT), morphological, morphometric and biochemical analyses. Results And Conclusions The obtained data suggest that scaffold integration and bone deposition are positively influenced by allotransplantated oAEC. Sinus explants derived from sheep grafted with oAEC engineered scaffolds displayed a reduced fibrotic reaction, a limited inflammatory response and an accelerated process of angiogenesis. In addition, the presence of oAEC significantly stimulated osteogenesis either by enhancing bone deposition or making more extent the foci of bone nucleation. Besides the modulatory role played by oAEC in the crucial events successfully guiding tissue regeneration (angiogenesis, vascular endothelial growth factor expression and inflammation), data provided herein show that oAEC were also able to directly participate in the process of bone deposition, as suggested by the presence of oAEC entrapped within the newly deposited osteoid matrix and by their ability to switch-on the expression of a specific bone-related protein (osteocalcin, OCN) when transplanted into host tissues. PMID:23696804

Tissue reaction to a titanium-nickelide mesh implant after plasty of postresection defects of anatomic structures of the chest.

PubMed

Topolnitskiy, E B; Dambaev, G Ts; Hodorenko, V N; Fomina, T I; Shefer, N A; Gunther, V E

2012-07-01

We studied morphological features of the regenerate formed after postresection defect plasty of the pericardium, diaphragm, and thorax with a mesh implant made of nanostructural titanium-nickelide threads. The newly formed tissue grew through the implant with the formation of an integrated tissue regenerate ensuring anatomic and physiological restoration of this area.

Evaluating the effectiveness of gel formulation of irradiated seed lectin Cratylia mollis during bone repair in rats

PubMed Central

Santos-Oliveira, Ralph; Lima-Ribeiro, Maria Helena Madruga; Carneiro-Leão, Ana Maria dos Anjos; Cruz, Adriana Ferreira; de Santana, Mauricélia Firmino; Cavalcanti, Carmelita de Lima Bezerra; de Pontes Filho, Nicodemos Teles; Coelho, Luana Cassandra Breitenbach Barroso; dos Santos Correia, Maria Tereza

2013-01-01

Context: Regeneration corresponds to the replacement of damaged cells with ones that have the same morphology and function. For experimental evaluation of materials that may favor the process of bone healing, defects are created with dimensions that prevent spontaneous regeneration. For the development and use of new drugs, it is necessary to study its effects in vitro, which depends on the formulation, concentration, and rate of irradiation in vivo and the route and frequency of administration; thus, it is possible to characterize the physiological and molecular mechanisms involved in the response and cellular effects. Objective: The objective of this study was to assess the effect of Cramoll-1,4 on the process of bone repair. Materials and Methods: A formulation of biopharmaceutical lectin Cramoll-1,4 at a concentration of 300 mg/100 mL was applied in a single application via gamma radiation and its effect on the process of bone repair in rats was assessed. Results: Histologically, it was observed that the bone defect is coated by loose connective tissue rich in fibroblasts, providing a range similar to the thick bone original and competing with site of new bone formation. This prevented direct contact between the formulation and experimental bone tissue, as, despite its proven effectiveness in experiments on the repair of skin lesions, the formulation used did not promote bone stimulation that would have promoted the tissue repair process. Conclusion: Because of the direct interference of loose tissue repair that prevented direct contact of the implant with the bone interface, the formulation did not promote bone stimulation. PMID:24083142

Development of biomaterial scaffold for nerve tissue engineering: Biomaterial mediated neural regeneration

PubMed Central

2009-01-01

Neural tissue repair and regeneration strategies have received a great deal of attention because it directly affects the quality of the patient's life. There are many scientific challenges to regenerate nerve while using conventional autologous nerve grafts and from the newly developed therapeutic strategies for the reconstruction of damaged nerves. Recent advancements in nerve regeneration have involved the application of tissue engineering principles and this has evolved a new perspective to neural therapy. The success of neural tissue engineering is mainly based on the regulation of cell behavior and tissue progression through the development of a synthetic scaffold that is analogous to the natural extracellular matrix and can support three-dimensional cell cultures. As the natural extracellular matrix provides an ideal environment for topographical, electrical and chemical cues to the adhesion and proliferation of neural cells, there exists a need to develop a synthetic scaffold that would be biocompatible, immunologically inert, conducting, biodegradable, and infection-resistant biomaterial to support neurite outgrowth. This review outlines the rationale for effective neural tissue engineering through the use of suitable biomaterials and scaffolding techniques for fabrication of a construct that would allow the neurons to adhere, proliferate and eventually form nerves. PMID:19939265

Proresolving Nanomedicines Activate Bone Regeneration in Periodontitis

PubMed Central

Hasturk, H.; Kantarci, A.; Freire, M.O.; Nguyen, D.; Dalli, J.; Serhan, C.N.

2015-01-01

Therapies to reverse tissue damage from osteolytic inflammatory diseases are limited by the inability of current tissue-engineering procedures to restore lost hard and soft tissues. There is a critical need for new therapeutics in regeneration. In addition to scaffolds, cells, and soluble mediators necessary for tissue engineering, control of endogenous inflammation is an absolute requirement for success. Although significant progress has been made in understanding natural resolution of inflammation pathways to limit uncontrolled inflammation in disease, harnessing the biomimetic properties of proresolving lipid mediators has not been demonstrated. Here, we report the use of nano-proresolving medicines (NPRM) containing a novel lipoxin analog (benzo-lipoxin A4, bLXA4) to promote regeneration of hard and soft tissues irreversibly lost to periodontitis in the Hanford miniature pig. In this proof-of-principle experiment, NPRM-bLXA4 dramatically reduced inflammatory cell infiltrate into chronic periodontal disease sites treated surgically and dramatically increased new bone formation and regeneration of the periodontal organ. These findings indicate that NPRM-bLXA4 is a mimetic of endogenous resolving mechanisms with potent bioactions that offers a new therapeutic tissue-engineering approach for the treatment of chronic osteolytic inflammatory diseases. PMID:25389003

Proresolving nanomedicines activate bone regeneration in periodontitis.

PubMed

Van Dyke, T E; Hasturk, H; Kantarci, A; Freire, M O; Nguyen, D; Dalli, J; Serhan, C N

2015-01-01

Therapies to reverse tissue damage from osteolytic inflammatory diseases are limited by the inability of current tissue-engineering procedures to restore lost hard and soft tissues. There is a critical need for new therapeutics in regeneration. In addition to scaffolds, cells, and soluble mediators necessary for tissue engineering, control of endogenous inflammation is an absolute requirement for success. Although significant progress has been made in understanding natural resolution of inflammation pathways to limit uncontrolled inflammation in disease, harnessing the biomimetic properties of proresolving lipid mediators has not been demonstrated. Here, we report the use of nano-proresolving medicines (NPRM) containing a novel lipoxin analog (benzo-lipoxin A4, bLXA4) to promote regeneration of hard and soft tissues irreversibly lost to periodontitis in the Hanford miniature pig. In this proof-of-principle experiment, NPRM-bLXA4 dramatically reduced inflammatory cell infiltrate into chronic periodontal disease sites treated surgically and dramatically increased new bone formation and regeneration of the periodontal organ. These findings indicate that NPRM-bLXA4 is a mimetic of endogenous resolving mechanisms with potent bioactions that offers a new therapeutic tissue-engineering approach for the treatment of chronic osteolytic inflammatory diseases. © International & American Associations for Dental Research 2014.

Hyaluronic Acid (HA) Scaffolds and Multipotent Stromal Cells (MSCs) in Regenerative Medicine.

PubMed

Prè, Elena Dai; Conti, Giamaica; Sbarbati, Andrea

2016-12-01

Traditional methods for tissue regeneration commonly used synthetic scaffolds to regenerate human tissues. However, they had several limitations, such as foreign body reactions and short time duration. In order to overcome these problems, scaffolds made of natural polymers are preferred. One of the most suitable and widely used materials to fabricate these scaffolds is hyaluronic acid. Hyaluronic acid is the primary component of the extracellular matrix of the human connective tissue. It is an ideal material for scaffolds used in tissue regeneration, thanks to its properties of biocompatibility, ease of chemical functionalization and degradability. In the last few years, especially from 2010, scientists have seen that the cell-based engineering of these natural scaffolds allows obtaining even better results in terms of tissue regeneration and the research started to grow in this direction. Multipotent stromal cells, also known as mesenchymal stem cells, plastic-adherent cells isolated from bone marrow and other mesenchymal tissues, with self-renew and multi-potency properties are ideal candidates for this aim. Normally, they are pre-seeded onto these scaffolds before their implantation in vivo. This review discusses the use of hyaluronic acid-based scaffolds together with multipotent stromal cells, as a very promising tool in regenerative medicine.

Sub-Periosteal Dissection with Denture-Guided Epithelial Regeneration: A Novel Method for Peri-Implant Soft Tissue Management in Reconstructed Mandibles.

PubMed

Kumar, Vinay V; Jacob, P C; Kuriakose, Moni A

2016-12-01

In patients with reconstructed mandibles using free fibula flaps, management of soft tissues around implants supporting dental rehabilitation, is often a clinical problem. The aim of this paper is to describe a new technique, namely "Sub-periosteal dissection and denture-guided epithelial regeneration (SD-DGER)", as a method of peri-implant soft tissue management in these patients. The technique consists of performing a subperiosteal dissection with creation of buccal and lingual flaps. These flaps form the buccal and lingual vestibule. Implants are placed and an interim denture is immediately loaded onto the implants to guide the regenerated epithelium. A keratinized mucosal layer is formed on the bare fibula bone in six months time. This technique was successful in producing fixed keratinized epithelial tissue around implants in patients with mandibles reconstructed using the free fibula flap in patients who did not undergo radiotherapy. The sub-periosteal dissection with denture guided epithelial regeneration is a predictable form of peri-implant soft tissue management in selected patients with reconstructed jaws.

Tissue‐specific reactions to positional discontinuities in the regenerating axolotl limb

PubMed Central

Avila, Daima; Roy, Molly; Seifert, Ashley W.

2015-01-01

Abstract We investigated cellular contributions to intercalary regenerates and 180o supernumerary limbs during axolotl limb regeneration using the cell autonomous green fluorescent protein marker and exchanged blastemas between white and green fluorescent protein animals. After distal blastemas were grafted to proximal levels tissues of the intercalary regenerate behaved independently with regard to the law of distal transformation; graft epidermis was replaced by stump epidermis, muscle‐derived cells, blood vessels, and Schwann cells of the distal blastema moved proximally to the stylopodium and cartilage and dermal cells conformed to the law. After 180o rotation, blastemas showed contributions from stump tissues which failed to alter patterning of the blastema. Supernumerary limbs were composed of stump and graft tissues and extensive contributions of stump tissues generated inversions or duplications of polarity to produce limbs of mixed handedness. Tail skeletal muscle and cardiac muscle broke the law with cells derived from these tissues exhibiting an apparent anteroposterior polarity as they migrated to the anterior side of the blastema. We attribute this behavior to the possible presence of a chemotactic factor from the wound epidermis. PMID:26755943

Generation of cell type-specific monoclonal antibodies for the planarian and optimization of sample processing for immunolabeling.

PubMed

Forsthoefel, David J; Waters, Forrest A; Newmark, Phillip A

2014-12-21

Efforts to elucidate the cellular and molecular mechanisms of regeneration have required the application of methods to detect specific cell types and tissues in a growing cohort of experimental animal models. For example, in the planarian Schmidtea mediterranea, substantial improvements to nucleic acid hybridization and electron microscopy protocols have facilitated the visualization of regenerative events at the cellular level. By contrast, immunological resources have been slower to emerge. Specifically, the repertoire of antibodies recognizing planarian antigens remains limited, and a more systematic approach is needed to evaluate the effects of processing steps required during sample preparation for immunolabeling. To address these issues and to facilitate studies of planarian digestive system regeneration, we conducted a monoclonal antibody (mAb) screen using phagocytic intestinal cells purified from the digestive tracts of living planarians as immunogens. This approach yielded ten antibodies that recognized intestinal epitopes, as well as markers for the central nervous system, musculature, secretory cells, and epidermis. In order to improve signal intensity and reduce non-specific background for a subset of mAbs, we evaluated the effects of fixation and other steps during sample processing. We found that fixative choice, treatments to remove mucus and bleach pigment, as well as methods for tissue permeabilization and antigen retrieval profoundly influenced labeling by individual antibodies. These experiments led to the development of a step-by-step workflow for determining optimal specimen preparation for labeling whole planarians as well as unbleached histological sections. We generated a collection of monoclonal antibodies recognizing the planarian intestine and other tissues; these antibodies will facilitate studies of planarian tissue morphogenesis. We also developed a protocol for optimizing specimen processing that will accelerate future efforts to generate planarian-specific antibodies, and to extend functional genetic studies of regeneration to post-transcriptional aspects of gene expression, such as protein localization or modification. Our efforts demonstrate the importance of systematically testing multiple approaches to species-specific idiosyncracies, such as mucus removal and pigment bleaching, and may serve as a template for the development of immunological resources in other emerging model organisms.

Stem cell derived endochondral cartilage stimulates bone healing by tissue transformation

PubMed Central

Bahney, Chelsea S; Hu, Diane P; Taylor, Aaron J; Ferro, Federico; Britz, Hayley M; Hallgrimsson, Benedikt; Johnstone, Brian; Miclau, Theodore; Marcucio, Ralph S

2016-01-01

Although bone has great capacity for repair, there are a number of clinical situations (fracture non-unions, spinal fusions, revision arthroplasty, segmental defects) in which auto- or allografts augment bone regeneration. Critical failures associated with current grafting treatments include osteonecrosis and limited integration between graft and host tissue. We speculated that the underlying problem with current bone grafting techniques is that they promote bone regeneration through direct osteogenesis. We hypothesized that using cartilage to promote endochondral bone regeneration would leverage normal developmental and repair sequences to produce a well-vascularized regenerate that integrates with the host tissue. In this study we use a translational murine model of a segmental tibia defect to test the clinical utility of bone regeneration from a cartilage graft. We further test the mechanism by which cartilage promotes bone regeneration using in vivo lineage tracing and in vitro culture experiments. Our data show that cartilage grafts support regeneration of a vascularized and integrated bone tissue in vivo, and subsequently propose a translational tissue engineering platform using chondrogenesis of MSCs. Interestingly, lineage tracing experiments show the regenerate was graft derived, suggesting transformation of the chondrocytes into bone. In vitro culture data shows that cartilage explants mineralize with the addition of BMP or by exposure to HUVEC conditioned medium, indicating that endothelial cells directly promote ossification. This study provides pre-clinical data for endochondral bone repair that has potential to significantly improve patient outcomes in a variety of musculoskeletal diseases and injuries. Further, in contrast to the dogmatic view that hypertrophic chondrocytes undergo apoptosis prior to bone formation, our data suggest cartilage can transform into bone by activating the pluripotent transcription factor Oct4A. Together these data represent a paradigm shift describing the mechanism of endochondral bone repair and open the door for novel regenerative strategies based on improved biology. PMID:24259230

Promise of periodontal ligament stem cells in regeneration of periodontium.

PubMed

Maeda, Hidefumi; Tomokiyo, Atsushi; Fujii, Shinsuke; Wada, Naohisa; Akamine, Akifumi

2011-07-28

A great number of patients around the world experience tooth loss that is attributed to irretrievable damage of the periodontium caused by deep caries, severe periodontal diseases or irreversible trauma. The periodontium is a complex tissue composed mainly of two soft tissues and two hard tissues; the former includes the periodontal ligament (PDL) tissue and gingival tissue, and the latter includes alveolar bone and cementum covering the tooth root. Tissue engineering techniques are therefore required for regeneration of these tissues. In particular, PDL is a dynamic connective tissue that is subjected to continual adaptation to maintain tissue size and width, as well as structural integrity, including ligament fibers and bone modeling. PDL tissue is central in the periodontium to retain the tooth in the bone socket, and is currently recognized to include somatic mesenchymal stem cells that could reconstruct the periodontium. However, successful treatment using these stem cells to regenerate the periodontium efficiently has not yet been developed. In the present article, we discuss the contemporary standpoints and approaches for these stem cells in the field of regenerative medicine in dentistry.

Biomechanics and mechanobiology in functional tissue engineering.

PubMed

Guilak, Farshid; Butler, David L; Goldstein, Steven A; Baaijens, Frank P T

2014-06-27

The field of tissue engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of "functional tissue engineering" has grown as a subfield of tissue engineering to address the challenges and questions on the role of biomechanics and mechanobiology in tissue engineering. Originally posed as a set of principles and guidelines for engineering of load-bearing tissues, functional tissue engineering has grown to encompass several related areas that have proven to have important implications for tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native tissues, scaffolds, and repair tissues; development of rationale criteria for the design and assessment of engineered tissues; investigation of the effects biomechanical factors on native and repair tissues, in vivo and in vitro; and development and application of computational models of tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered tissue replacements. Copyright © 2014 Elsevier Ltd. All rights reserved.

Protein-releasing polymeric scaffolds induce fibrochondrocytic differentiation of endogenous cells for knee meniscus regeneration in sheep.

PubMed

Lee, Chang H; Rodeo, Scott A; Fortier, Lisa Ann; Lu, Chuanyong; Erisken, Cevat; Mao, Jeremy J

2014-12-10

Regeneration of complex tissues, such as kidney, liver, and cartilage, continues to be a scientific and translational challenge. Survival of ex vivo cultured, transplanted cells in tissue grafts is among one of the key barriers. Meniscus is a complex tissue consisting of collagen fibers and proteoglycans with gradient phenotypes of fibrocartilage and functions to provide congruence of the knee joint, without which the patient is likely to develop arthritis. Endogenous stem/progenitor cells regenerated the knee meniscus upon spatially released human connective tissue growth factor (CTGF) and transforming growth factor-β3 (TGFβ3) from a three-dimensional (3D)-printed biomaterial, enabling functional knee recovery. Sequentially applied CTGF and TGFβ3 were necessary and sufficient to propel mesenchymal stem/progenitor cells, as a heterogeneous population or as single-cell progenies, into fibrochondrocytes that concurrently synthesized procollagens I and IIα. When released from microchannels of 3D-printed, human meniscus scaffolds, CTGF and TGFβ3 induced endogenous stem/progenitor cells to differentiate and synthesize zone-specific type I and II collagens. We then replaced sheep meniscus with anatomically correct, 3D-printed scaffolds that incorporated spatially delivered CTGF and TGFβ3. Endogenous cells regenerated the meniscus with zone-specific matrix phenotypes: primarily type I collagen in the outer zone, and type II collagen in the inner zone, reminiscent of the native meniscus. Spatiotemporally delivered CTGF and TGFβ3 also restored inhomogeneous mechanical properties in the regenerated sheep meniscus. Survival and directed differentiation of endogenous cells in a tissue defect may have implications in the regeneration of complex (heterogeneous) tissues and organs. Copyright © 2014, American Association for the Advancement of Science.

Pulp regeneration concepts for non-vital teeth: from tissue engineering to clinical approaches.

PubMed

Orti, Valérie; Collart-Dutilleul, Pierre-Yves; Piglionico, Sofía Silvia; Pall, Orsolya; Cuisinier, Frédéric; Panayotov, Ivan Vladislavov

2018-05-04

Following the basis of tissue engineering (Cells - Scaffold - Bioactive molecules), regenerative endodontic has emerged as a new concept of dental treatment. Clinical procedures have been proposed by endodontic practitioners willing to promote regenerative therapy. Preserving pulp vitality was a first approach. Later procedures aimed to regenerate a vascularized pulp in necrotic root canals. However, there is still no protocol allowing an effective regeneration of necrotic pulp tissue either in immature or mature teeth. This review explore in vitro and preclinical concepts developed during the last decade, especially the potential use of stem cells, bioactive molecules and scaffolds, and makes a comparison with the goals achieved so far in clinical practice. Regeneration of pulp-like tissue has been shown in various experimental conditions. However, the appropriate techniques are currently in a developmental stage. The ideal combination of scaffolds and growth factors to obtain a complete regeneration of the pulp-dentin complex is still unknown. The use of stem cells, especially from pulp origin, sounds promising for pulp regeneration therapy, but it has not been applied so far for clinical endodontics, in case of necrotic teeth. The gap observed between the hope raised from in vitro experiments and the reality of endodontic treatments suggests that clinical success may be achieved without external stem cell application. Therefore, procedures using the concept of cell homing, through evoked bleeding, that permit to recreate a living tissue that mimics the original pulp have been proposed. Perspectives for pulp tissue engineering in a near future include a better control of clinical parameters and pragmatic approach of the experimental results (autologous stem cells from cell homing, controlled release of growth factors). In the coming years, this therapeutic strategy will probably become a clinical reality, even for mature necrotic teeth.

Biomaterials based strategies for skeletal muscle tissue engineering: existing technologies and future trends.

PubMed

Qazi, Taimoor H; Mooney, David J; Pumberger, Matthias; Geissler, Sven; Duda, Georg N

2015-01-01

Skeletal muscles have a robust capacity to regenerate, but under compromised conditions, such as severe trauma, the loss of muscle functionality is inevitable. Research carried out in the field of skeletal muscle tissue engineering has elucidated multiple intrinsic mechanisms of skeletal muscle repair, and has thus sought to identify various types of cells and bioactive factors which play an important role during regeneration. In order to maximize the potential therapeutic effects of cells and growth factors, several biomaterial based strategies have been developed and successfully implemented in animal muscle injury models. A suitable biomaterial can be utilized as a template to guide tissue reorganization, as a matrix that provides optimum micro-environmental conditions to cells, as a delivery vehicle to carry bioactive factors which can be released in a controlled manner, and as local niches to orchestrate in situ tissue regeneration. A myriad of biomaterials, varying in geometrical structure, physical form, chemical properties, and biofunctionality have been investigated for skeletal muscle tissue engineering applications. In the current review, we present a detailed summary of studies where the use of biomaterials favorably influenced muscle repair. Biomaterials in the form of porous three-dimensional scaffolds, hydrogels, fibrous meshes, and patterned substrates with defined topographies, have each displayed unique benefits, and are discussed herein. Additionally, several biomaterial based approaches aimed specifically at stimulating vascularization, innervation, and inducing contractility in regenerating muscle tissues are also discussed. Finally, we outline promising future trends in the field of muscle regeneration involving a deeper understanding of the endogenous healing cascades and utilization of this knowledge for the development of multifunctional, hybrid, biomaterials which support and enable muscle regeneration under compromised conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dual delivery of rhPDGF-BB and bone marrow mesenchymal stromal cells expressing the BMP2 gene enhance bone formation in a critical-sized defect model.

PubMed

Park, Shin-Young; Kim, Kyoung-Hwa; Shin, Seung-Yun; Koo, Ki-Tae; Lee, Yong-Moo; Seol, Yang-Jo

2013-11-01

Bone tissue healing is a dynamic, orchestrated process that relies on multiple growth factors and cell types. Platelet-derived growth factor-BB (PDGF-BB) is released from platelets at wound sites and induces cellular migration and proliferation necessary for bone regeneration in the early healing process. Bone morphogenetic protein-2 (BMP-2), the most potent osteogenic differentiation inducer, directs new bone formation at the sites of bone defects. This study evaluated a combinatorial treatment protocol of PDGF-BB and BMP-2 on bone healing in a critical-sized defect model. To mimic the bone tissue healing process, a dual delivery approach was designed to deliver the rhPDGF-BB protein transiently during the early healing phase, whereas BMP-2 was supplied by rat bone marrow stromal cells (BMSCs) transfected with an adenoviral vector containing the BMP2 gene (AdBMP2) for prolonged release throughout the healing process. In in vitro experiments, the dual delivery of rhPDGF-BB and BMP2 significantly enhanced cell proliferation. However, the osteogenic differentiation of BMSCs was significantly suppressed even though the amount of BMP-2 secreted by the AdBMP2-transfected BMSCs was not significantly affected by the rhPDGF-BB treatment. In addition, dual delivery inhibited the mRNA expression of BMP receptor type II and Noggin in BMSCs. In in vivo experiments, critical-sized calvarial defects in rats showed enhanced bone regeneration by dual delivery of autologous AdBMP2-transfected BMSCs and rhPDGF-BB in both the amount of new bone formed and the bone mineral density. These enhancements in bone regeneration were greater than those observed in the group treated with AdBMP2-transfected BMSCs alone. In conclusion, the dual delivery of rhPDGF-BB and AdBMP2-transfected BMSCs improved the quality of the regenerated bone, possibly due to the modulation of PDGF-BB on BMP-2-induced osteogenesis.

Future dentistry: cell therapy meets tooth and periodontal repair and regeneration

PubMed Central

Catón, Javier; Bostanci, Nagihan; Remboutsika, Eumorphia; De Bari, Cosimo; Mitsiadis, Thimios A

2011-01-01

Abstract Cell-based tissue repair of the tooth and – tooth-supporting – periodontal ligament (PDL) is a new attractive approach that complements traditional restorative or surgical techniques for replacement of injured or pathologically damaged tissues. In such therapeutic approaches, stem cells and/or progenitor cells are manipulated in vitro and administered to patients as living and dynamic biological agents. In this review, we discuss the clonogenic potential of human dental and periodontal tissues such as the dental pulp and the PDL and their potential for tooth and periodontal repair and/or regeneration. We propose novel therapeutic approaches using stem cells or progenitor cells, which are targeted to regenerate the lost dental or periodontal tissue. PMID:21199329

Tissue engineered constructs for peripheral nerve surgery

PubMed Central

Johnson, P. J.; Wood, M. D.; Moore, A. M.; Mackinnon, S. E.

2013-01-01

Summary Background Tissue engineering has been defined as “an interdisciplinary field that applies the principles of engineering and life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function or a whole organ”. Traumatic peripheral nerve injury resulting in significant tissue loss at the zone of injury necessitates the need for a bridge or scaffold for regenerating axons from the proximal stump to reach the distal stump. Methods A review of the literature was used to provide information on the components necessary for the development of a tissue engineered peripheral nerve substitute. Then, a comprehensive review of the literature is presented composed of the studies devoted to this goal. Results Extensive research has been directed toward the development of a tissue engineered peripheral nerve substitute to act as a bridge for regenerating axons from the proximal nerve stump seeking the distal nerve. Ideally this nerve substitute would consist of a scaffold component that mimics the extracellular matrix of the peripheral nerve and a cellular component that serves to stimulate and support regenerating peripheral nerve axons. Conclusions The field of tissue engineering should consider its challenge to not only meet the autograft “gold standard” but also to understand what drives and inhibits nerve regeneration in order to surpass the results of an autograft. PMID:24385980

Trophic factors from adipose tissue-derived multi-lineage progenitor cells promote cytodifferentiation of periodontal ligament cells.

PubMed

Sawada, Keigo; Takedachi, Masahide; Yamamoto, Satomi; Morimoto, Chiaki; Ozasa, Masao; Iwayama, Tomoaki; Lee, Chun Man; Okura, Hanayuki; Matsuyama, Akifumi; Kitamura, Masahiro; Murakami, Shinya

2015-08-14

Stem and progenitor cells are currently being investigated for their applicability in cell-based therapy for periodontal tissue regeneration. We recently demonstrated that the transplantation of adipose tissue-derived multi-lineage progenitor cells (ADMPCs) enhances periodontal tissue regeneration in beagle dogs. However, the molecular mechanisms by which transplanted ADMPCs induce periodontal tissue regeneration remain to be elucidated. In this study, trophic factors released by ADMPCs were examined for their paracrine effects on human periodontal ligament cell (HPDL) function. ADMPC conditioned medium (ADMPC-CM) up-regulated osteoblastic gene expression, alkaline phosphatase activity and calcified nodule formation in HPDLs, but did not significantly affect their proliferative response. ADMPCs secreted a number of growth factors, including insulin-like growth factor binding protein 6 (IGFBP6), hepatocyte growth factor and vascular endothelial growth factor. Among these, IGFBP6 was most highly expressed. Interestingly, the positive effects of ADMPC-CM on HPDL differentiation were significantly suppressed by transfecting ADMPCs with IGFBP6 siRNA. Our results suggest that ADMPCs transplanted into a defect in periodontal tissue release trophic factors that can stimulate the differentiation of HPDLs to mineralized tissue-forming cells, such as osteoblasts and cementoblasts. IGFBP6 may play crucial roles in ADMPC-induced periodontal regeneration. Copyright © 2015 Elsevier Inc. All rights reserved.