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Sample records for cartilage repair response

  1. Gene Therapy for Cartilage Repair

    PubMed Central

    Madry, Henning; Orth, Patrick; Cucchiarini, Magali

    2011-01-01

    The concept of using gene transfer strategies for cartilage repair originates from the idea of transferring genes encoding therapeutic factors into the repair tissue, resulting in a temporarily and spatially defined delivery of therapeutic molecules to sites of cartilage damage. This review focuses on the potential benefits of using gene therapy approaches for the repair of articular cartilage and meniscal fibrocartilage, including articular cartilage defects resulting from acute trauma, osteochondritis dissecans, osteonecrosis, and osteoarthritis. Possible applications for meniscal repair comprise meniscal lesions, meniscal sutures, and meniscal transplantation. Recent studies in both small and large animal models have demonstrated the applicability of gene-based approaches for cartilage repair. Chondrogenic pathways were stimulated in the repair tissue and in osteoarthritic cartilage using genes for polypeptide growth factors and transcription factors. Although encouraging data have been generated, a successful translation of gene therapy for cartilage repair will require an ongoing combined effort of orthopedic surgeons and of basic scientists. PMID:26069580

  2. Signaling Pathways in Cartilage Repair

    PubMed Central

    Mariani, Erminia; Pulsatelli, Lia; Facchini, Andrea

    2014-01-01

    In adult healthy cartilage, chondrocytes are in a quiescent phase characterized by a fine balance between anabolic and catabolic activities. In ageing, degenerative joint diseases and traumatic injuries of cartilage, a loss of homeostatic conditions and an up-regulation of catabolic pathways occur. Since cartilage differentiation and maintenance of homeostasis are finely tuned by a complex network of signaling molecules and biophysical factors, shedding light on these mechanisms appears to be extremely relevant for both the identification of pathogenic key factors, as specific therapeutic targets, and the development of biological approaches for cartilage regeneration. This review will focus on the main signaling pathways that can activate cellular and molecular processes, regulating the functional behavior of cartilage in both physiological and pathological conditions. These networks may be relevant in the crosstalk among joint compartments and increased knowledge in this field may lead to the development of more effective strategies for inducing cartilage repair. PMID:24837833

  3. Animal models of cartilage repair

    PubMed Central

    Cook, J. L.; Hung, C. T.; Kuroki, K.; Stoker, A. M.; Cook, C. R.; Pfeiffer, F. M.; Sherman, S. L.; Stannard, J. P.

    2014-01-01

    Cartilage repair in terms of replacement, or regeneration of damaged or diseased articular cartilage with functional tissue, is the ‘holy grail’ of joint surgery. A wide spectrum of strategies for cartilage repair currently exists and several of these techniques have been reported to be associated with successful clinical outcomes for appropriately selected indications. However, based on respective advantages, disadvantages, and limitations, no single strategy, or even combination of strategies, provides surgeons with viable options for attaining successful long-term outcomes in the majority of patients. As such, development of novel techniques and optimisation of current techniques need to be, and are, the focus of a great deal of research from the basic science level to clinical trials. Translational research that bridges scientific discoveries to clinical application involves the use of animal models in order to assess safety and efficacy for regulatory approval for human use. This review article provides an overview of animal models for cartilage repair. Cite this article: Bone Joint Res 2014;4:89–94. PMID:24695750

  4. Magnetic Resonance Imaging of Cartilage Repair

    PubMed Central

    Trattnig, Siegfried; Winalski, Carl S.; Marlovits, Stephan; Jurvelin, Jukka S.; Welsch, Goetz H.; Potter, Hollis G.

    2011-01-01

    Articular cartilage lesions are a common pathology of the knee joint, and many patients may benefit from cartilage repair surgeries that offer the chance to avoid the development of osteoarthritis or delay its progression. Cartilage repair surgery, no matter the technique, requires a noninvasive, standardized, and high-quality longitudinal method to assess the structure of the repair tissue. This goal is best fulfilled by magnetic resonance imaging (MRI). The present article provides an overview of the current state of the art of MRI of cartilage repair. In the first 2 sections, preclinical and clinical MRI of cartilage repair tissue are described with a focus on morphological depiction of cartilage and the use of functional (biochemical) MR methodologies for the visualization of the ultrastructure of cartilage repair. In the third section, a short overview is provided on the regulatory issues of the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMEA) regarding MR follow-up studies of patients after cartilage repair surgeries. PMID:26069565

  5. [Cell therapy in cartilage repair: cellular and molecular bases].

    PubMed

    Corvol, Marie-Thérèse; Tahiri, Khadija; Montembault, Alexandra; Daumard, Alain; Savouret, Jean-François; Rannou, François

    2008-01-01

    The destruction of articular cartilage represents the outcome of most inflammatory and degenerative rheumatic diseases and leads to severe disability. Articular cartilage being unable to repair spontaneously, alterations of the joint surface often results in end-stage osteoarthritis, requiring surgical intervention and total joint replacement. This makes damaged tissues repair a major challenge in our aging society. Cartilage harbors only one cell type, the chondrocyte, which synthesizes and secretes specific matrix proteins such as type II collagen and high molecular weight proteoglycans. Matrix proteins are responsible for the conservation of the chondrocyte phenotype and the maintenance of the mechanical functions of cartilage. Development of therapeutic strategies for cartilage repair should thus comprise not only the replacement of lost cartilage cells but also that of extracellular matrix with cartilage-like properties. Different protocols are under investigation. The most commonly employed materials include transplantation of autologous osteochondral tissue. More recently, cell-based therapies using autologous mature chondrocytes or pre-chondrogenic stem cells have drawn particular attention. Tissue-engineering procedures represent the actual trend in cartilage repair. This approach combines biodegradable polymeric three-dimensional matrixes and isolated prechondrogenic stem cells. The cells are seeded within the biocompatible matrix and then implanted into the joint. Numerous non-degradable and degradable polymers, which efficiently "mimic" the natural surroundings of cartilage cells, are currently under investigation.

  6. Cellular and Acellular Approaches for Cartilage Repair

    PubMed Central

    2015-01-01

    There are several choices of cells to use for cartilage repair. Cells are used as internal or external sources and sometimes in combination. In this article, an analysis of the different cell choices and their use and potential is provided. Embryonic cartilage formation is of importance when finding more about how to be able to perfect cartilage repair. Some suggestions for near future research based on up-to-date knowledge on chondrogenic cells are given to hopefully stimulate more studies on the final goal of cartilage regeneration. PMID:27340516

  7. Local Morphological Response of the Distal Femoral Articular–Epiphyseal Cartilage Complex of Young Foals to Surgical Stab Incision and Potential Relevance to Cartilage Injury and Repair in Children

    PubMed Central

    Hendrickson, Eli H.S.; Ekman, Stina; Carlson, Cathy S.; Dolvik, Nils I.

    2013-01-01

    Objective: Describe the local morphological response of the articular–epiphyseal cartilage complex to surgical stab incision in the distal femur of foals, with emphasis on the relationship between growth cartilage injury, enchondral ossification, and repair. Design: Nine foals were induced into general anesthesia at the age of 13 to 15 days. Four full-thickness stab incision defects were created in the cartilage on the lateral aspect of the lateral trochlear ridge of the left distal femur. Follow-up examination was carried out from 1 to 49 days postoperatively, including examination of intact bones, sawed slabs, and histological sections. Results: Incision defects filled with cells displaying fibroblast-, chondrocyte-, and osteoblast-like characteristics, potentially validating the rationale behind the drilling of stable juvenile osteochondritis dissecans lesions in children. Incisions induced necrosis within the cartilage on the margins at all depths of the defects. Sharp dissection may therefore be contraindicated in cartilage repair in young individuals. Incisions caused a focal delay in enchondral ossification in 2 foals, apparently related to the orientation of the incision defect relative to the direction of ossification. Defects became progressively surrounded by subchondral bone, in which granulation tissue containing clasts and foci of osteoblast-like cells was observed. Continued enchondral ossification was therefore likely to result in healing of uncomplicated defects to morphologically normal bone. Conclusions: Epiphyseal growth cartilage injury had the potential to exert a negative effect on enchondral ossification. Enchondral ossification exerted a beneficial effect on repair. This relationship warrants consideration in future studies of cartilage injury and repair within the articular–epiphyseal cartilage complex of all species. PMID:26069670

  8. Regulatory Challenges for Cartilage Repair Technologies.

    PubMed

    McGowan, Kevin B; Stiegman, Glenn

    2013-01-01

    In the United States, few Food and Drug Administration (FDA)-approved options exist for the treatment of focal cartilage and osteochondral lesions. Developers of products for cartilage repair face many challenges to obtain marketing approval from the FDA. The objective of this review is to discuss the necessary steps for FDA application and approval for a new cartilage repair product. FDA Guidance Documents, FDA Panel Meetings, scientific organization recommendations, and clinicaltrials.gov were reviewed to demonstrate the current thinking of FDA and the scientific community on the regulatory process for cartilage repair therapies. Cartilage repair therapies can receive market approval from FDA as medical devices, drugs, or biologics, and the specific classification of product can affect the nonclinical, clinical, and regulatory strategy to bring the product to market. Recent FDA guidance gives an outline of the required elements to bring a cartilage repair product to market, although these standards are often very general. As a result, companies have to carefully craft their study patient population, comparator group, and clinical endpoint to best showcase their product's attributes. In addition, regulatory strategy and manufacturing process validation need to be considered early in the clinical study process to allow for timely product approval following the completion of clinical study. Although the path to regulatory approval for a cartilage repair therapy is challenging and time-consuming, proper clinical trial planning and attention to the details can eventually save companies time and money by bringing a product to the market in the most expeditious process possible.

  9. Supporting Biomaterials for Articular Cartilage Repair

    PubMed Central

    Duarte Campos, Daniela Filipa; Drescher, Wolf; Rath, Björn; Tingart, Markus

    2012-01-01

    Orthopedic surgeons and researchers worldwide are continuously faced with the challenge of regenerating articular cartilage defects. However, until now, it has not been possible to completely mimic the biological and biochemical properties of articular cartilage using current research and development approaches. In this review, biomaterials previously used for articular cartilage repair research are addressed. Furthermore, a brief discussion of the state of the art of current cell printing procedures mimicking native cartilage is offered in light of their use as future alternatives for cartilage tissue engineering. Inkjet cell printing, controlled deposition cell printing tools, and laser cell printing are cutting-edge techniques in this context. The development of mimetic hydrogels with specific biological properties relevant to articular cartilage native tissue will support the development of improved, functional, and novel engineered tissue for clinical application. PMID:26069634

  10. Induced pluripotent stem cells in cartilage repair

    PubMed Central

    Lietman, Steven A

    2016-01-01

    Articular cartilage repair techniques are challenging. Human embryonic stem cells and induced pluripotent stem cells (iPSCs) theoretically provide an unlimited number of specialized cells which could be used in articular cartilage repair. However thus far chondrocytes from iPSCs have been created primarily by viral transfection and with the use of cocultured feeder cells. In addition chondrocytes derived from iPSCs have usually been formed in condensed cell bodies (resembling embryoid bodies) that then require dissolution with consequent substantial loss of cell viability and phenotype. All of these current techniques used to derive chondrocytes from iPSCs are problematic but solutions to these problems are on the horizon. These solutions will make iPSCs a viable alternative for articular cartilage repair in the near future. PMID:27004161

  11. Induced pluripotent stem cells in cartilage repair.

    PubMed

    Lietman, Steven A

    2016-03-18

    Articular cartilage repair techniques are challenging. Human embryonic stem cells and induced pluripotent stem cells (iPSCs) theoretically provide an unlimited number of specialized cells which could be used in articular cartilage repair. However thus far chondrocytes from iPSCs have been created primarily by viral transfection and with the use of cocultured feeder cells. In addition chondrocytes derived from iPSCs have usually been formed in condensed cell bodies (resembling embryoid bodies) that then require dissolution with consequent substantial loss of cell viability and phenotype. All of these current techniques used to derive chondrocytes from iPSCs are problematic but solutions to these problems are on the horizon. These solutions will make iPSCs a viable alternative for articular cartilage repair in the near future. PMID:27004161

  12. Hydrogel-Based Controlled Delivery Systems for Articular Cartilage Repair

    PubMed Central

    Madry, Henning

    2016-01-01

    Delivery of bioactive factors is a very valuable strategy for articular cartilage repair. Nevertheless, the direct supply of such biomolecules is limited by several factors including rapid degradation, the need for supraphysiological doses, the occurrence of immune and inflammatory responses, and the possibility of dissemination to nontarget sites that may impair their therapeutic action and raise undesired effects. The use of controlled delivery systems has the potential of overcoming these hurdles by promoting the temporal and spatial presentation of such factors in a defined target. Hydrogels are promising materials to develop delivery systems for cartilage repair as they can be easily loaded with bioactive molecules controlling their release only where required. This review exposes the most recent technologies on the design of hydrogels as controlled delivery platforms of bioactive molecules for cartilage repair. PMID:27642587

  13. Hydrogel-Based Controlled Delivery Systems for Articular Cartilage Repair.

    PubMed

    Rey-Rico, Ana; Madry, Henning; Cucchiarini, Magali

    2016-01-01

    Delivery of bioactive factors is a very valuable strategy for articular cartilage repair. Nevertheless, the direct supply of such biomolecules is limited by several factors including rapid degradation, the need for supraphysiological doses, the occurrence of immune and inflammatory responses, and the possibility of dissemination to nontarget sites that may impair their therapeutic action and raise undesired effects. The use of controlled delivery systems has the potential of overcoming these hurdles by promoting the temporal and spatial presentation of such factors in a defined target. Hydrogels are promising materials to develop delivery systems for cartilage repair as they can be easily loaded with bioactive molecules controlling their release only where required. This review exposes the most recent technologies on the design of hydrogels as controlled delivery platforms of bioactive molecules for cartilage repair. PMID:27642587

  14. Hydrogel-Based Controlled Delivery Systems for Articular Cartilage Repair

    PubMed Central

    Madry, Henning

    2016-01-01

    Delivery of bioactive factors is a very valuable strategy for articular cartilage repair. Nevertheless, the direct supply of such biomolecules is limited by several factors including rapid degradation, the need for supraphysiological doses, the occurrence of immune and inflammatory responses, and the possibility of dissemination to nontarget sites that may impair their therapeutic action and raise undesired effects. The use of controlled delivery systems has the potential of overcoming these hurdles by promoting the temporal and spatial presentation of such factors in a defined target. Hydrogels are promising materials to develop delivery systems for cartilage repair as they can be easily loaded with bioactive molecules controlling their release only where required. This review exposes the most recent technologies on the design of hydrogels as controlled delivery platforms of bioactive molecules for cartilage repair.

  15. Cartilage Repair and Subchondral Bone Remodeling in Response to Focal Lesions in a Mini-Pig Model: Implications for Tissue Engineering

    PubMed Central

    Fisher, Matthew B.; Belkin, Nicole S.; Milby, Andrew H.; Henning, Elizabeth A.; Bostrom, Marc; Kim, Minwook; Pfeifer, Christian; Meloni, Gregory; Dodge, George R.; Burdick, Jason A.; Schaer, Thomas P.; Steinberg, David R.

    2015-01-01

    Objective: Preclinical large animal models are essential for evaluating new tissue engineering (TE) technologies and refining surgical approaches for cartilage repair. Some preclinical animal studies, including the commonly used minipig model, have noted marked remodeling of the subchondral bone. However, the mechanisms underlying this response have not been well characterized. Thus, our objective was to compare in-vivo outcomes of chondral defects with varied injury depths and treatments. Design: Trochlear chondral defects were created in 11 Yucatan minipigs (6 months old). Groups included an untreated partial-thickness defect (PTD), an untreated full-thickness defect (FTD), and FTDs treated with microfracture, autologous cartilage transfer (FTD-ACT), or an acellular hyaluronic acid hydrogel. Six weeks after surgery, micro-computed tomography (μCT) was used to quantitatively assess defect fill and subchondral bone remodeling. The quality of cartilage repair was assessed using the ICRS-II histological scoring system and immunohistochemistry for type II collagen. A finite element model (FEM) was developed to assess load transmission. Results: Using μCT, substantial bone remodeling was observed for all FTDs, but not for the PTD group. The best overall histological scores and greatest type II collagen staining was found for the FTD-ACT and PTD groups. The FEM confirmed that only the FTD-ACT group could initially restore appropriate transfer of compressive loads to the underlying bone. Conclusions: The bony remodeling observed in this model system appears to be a biological phenomena and not a result of altered mechanical loading, with the depth of the focal chondral defect (partial vs. full thickness) dictating the bony remodeling response. The type of cartilage injury should be carefully controlled in studies utilizing this model to evaluate TE approaches for cartilage repair. PMID:25318414

  16. Nano-approaches in cartilage repair.

    PubMed

    Giannoni, Paolo; Narcisi, Roberto

    2009-01-01

    Technological improvements in biology, medicine, chemistry, engineering and material science have allowed deeper insights into the architectural and molecular organization levels of tissues and materials, providing innovative approaches and tools for medical treatments. One of the therapeutic targets that may benefit from these new issues is damaged human articular cartilage, a tissue unable to self-heal. In this review, we have not taken into consideration the pathological degenerations that may cause cartilage damage, but we have concentrated on the means of repair, providing a brief overview of the consolidated cellbased approaches for cartilage resurfacing. However, we have also focused on the tight relationships between chondrocytes and their surrounding extracellular matrix. The aim was to evidence the requirements of the cell components of the tissue, the un-fulfillment of which may cause unsatisfactory therapeutic outcomes in present therapies. A deeper analysis of the structural microand nano-characteristics of the articular cartilage matrix is presented to motivate the most recent "nano-approaches" that have been developed and published in the literature. Nanofiber technology, material surface topography and bioactivation, and recent advances in nanoparticle modifications are thus considered for their interesting contributions aimed at improving tissue engineering-based cartilage repair.

  17. Strategies for Controlled Delivery of Biologics for Cartilage Repair

    PubMed Central

    Lam, Johnny; Lu, Steven; Kasper, F. Kurtis; Mikos, Antonios G.

    2014-01-01

    The delivery of biologics is an important component in the treatment of osteoarthritis and the functional restoration of articular cartilage. Numerous factors have been implicated in the cartilage repair process, but the uncontrolled delivery of these factors may not only reduce their full reparative potential and can also cause unwanted morphological effects. It is therefore imperative to consider the type of biologic to be delivered, the method of delivery, and the temporal as well as spatial presentation of the biologic to achieve the desired effect in cartilage repair. Additionally, the delivery of a single factor may not be sufficient in guiding neo-tissue formation, motivating recent research towards the delivery of multiple factors. This review will discuss the roles of various biologics involved in cartilage repair and the different methods of delivery for appropriate healing responses. A number of spatiotemporal strategies will then be emphasized for the controlled delivery of single and multiple bioactive factors in both in vitro and in vivo cartilage tissue engineering applications. PMID:24993610

  18. Generating Cartilage Repair from Pluripotent Stem Cells

    PubMed Central

    Cheng, Aixin; Hardingham, Timothy E.

    2014-01-01

    The treatment of degeneration and injury of articular cartilage has been very challenging for scientists and surgeons. As an avascular and hypocellular tissue, cartilage has a very limited capacity for self-repair. Chondrocytes are the only cell type in cartilage, in which they are surrounded by the extracellular matrix that they secrete and assemble. Autologous chondrocyte implantation for cartilage defects has achieved good results, but the limited resources and complexity of the procedure have hindered wider application. Stem cells form an alternative to chondrocytes as a source of chondrogenic cells due to their ability to proliferate extensively while retaining the potential for differentiation. Adult stem cells such as mesenchymal stem cells have been differentiated into chondrocytes, but the limitations in their proliferative ability and the heterogeneous cell population hinder their adoption as a prime alternative source for generating chondrocytes. Human embryonic stem cells (hESCs) are attractive as candidates for cell replacement therapy because of their unlimited self-renewal and ability for differentiation into mesodermal derivatives as well as other lineages. In this review, we focus on current protocols for chondrogenic differentiation of ESCs, in particular the chemically defined culture system developed in our lab that could potentially be adapted for clinical application. PMID:23957872

  19. Mechanical properties of hyaline and repair cartilage studied by nanoindentation.

    PubMed

    Franke, O; Durst, K; Maier, V; Göken, M; Birkholz, T; Schneider, H; Hennig, F; Gelse, K

    2007-11-01

    Articular cartilage is a highly organized tissue that is well adapted to the functional demands in joints but difficult to replicate via tissue engineering or regeneration. Its viscoelastic properties allow cartilage to adapt to both slow and rapid mechanical loading. Several cartilage repair strategies that aim to restore tissue and protect it from further degeneration have been introduced. The key to their success is the quality of the newly formed tissue. In this study, periosteal cells loaded on a scaffold were used to repair large partial-thickness cartilage defects in the knee joint of miniature pigs. The repair cartilage was analyzed 26 weeks after surgery and compared both morphologically and mechanically with healthy hyaline cartilage. Contact stiffness, reduced modulus and hardness as key mechanical properties were examined in vitro by nanoindentation in phosphate-buffered saline at room temperature. In addition, the influence of tissue fixation with paraformaldehyde on the biomechanical properties was investigated. Although the repair process resulted in the formation of a stable fibrocartilaginous tissue, its contact stiffness was lower than that of hyaline cartilage by a factor of 10. Fixation with paraformaldehyde significantly increased the stiffness of cartilaginous tissue by one order of magnitude, and therefore, should not be used when studying biomechanical properties of cartilage. Our study suggests a sensitive method for measuring the contact stiffness of articular cartilage and demonstrates the importance of mechanical analysis for proper evaluation of the success of cartilage repair strategies. PMID:17586107

  20. Cartilage change after arthroscopic repair for an isolated meniscal tear.

    PubMed

    Soejima, Takashi; Murakami, Hidetaka; Inoue, Takashi; Kanazawa, Tomonoshin; Katouda, Michihiro; Nagata, Kensei

    2005-01-01

    To investigate the direct effect to the cartilage caused by the meniscal repair, we examined patients who underwent an isolated meniscal repair without any other abnormalities by arthroscopic examination. A total of 17 patients were examined by second-look arthroscopy after an average interval of 9 months from the meniscal repair, and have been evaluated the status of the repaired meniscus and of the relative femoral condylar cartilage. Changes in the severity of the cartilage lesion between at the time of meniscal repair and the time of the second-look arthroscopy were considered based on the status of the repaired meniscus. Regardless of the healing status of the repair site, it was possible to prevent degeneration in the cartilage in 9 of the 10 patients who demonstrated no degeneration in the meniscal body. Of the 7 patients who demonstrated degeneration in the meniscal body, progression in cartilage degeneration was noted as 1 grade in 2 patients and 2 grades in another 3 patients. Even in those in which stable fusion of the repair site was achieved, the condition of the inner meniscal body was not necessarily maintained favorably in all cases, indicating that degeneration in the meniscal body was a risk factor for cartilage degeneration. It was concluded that recovery could not be expected even at 9 months after the repair if the lesion had already demonstrated degeneration in the meniscal body at the time of repair.

  1. Repair of osteochondral defects in rabbits with ectopically produced cartilage.

    PubMed

    Emans, Pieter J; Hulsbosch, Martine; Wetzels, Gwendolyn M R; Bulstra, Sjoerd K; Kuijer, Roel

    2005-01-01

    Cartilage has poor regenerative capacity. Donor site morbidity and interference with joint homeostasis should be considered when applying the autologous chondrocyte transplantation technique. The use of ectopically produced cartilage, derived from periosteum, might be a novel method to heal cartilage defects. Ectopic cartilage was produced by dissecting a piece of periosteum from the tibia of rabbits. After 14 days the reactive tissue at the dissection site was harvested and a graft was cored out and press-fit implanted in an osteochondral defect in the medial condyle of the femur with or without addition of hyaluronan. After 3 weeks and 3 months the repair reaction was evaluated by histology. Thionine- and collagen type II-stained sections were evaluated for graft viability, ingrowth of the graft, and joint surface repair. Empty defects remained empty 3 weeks after implantation, ectopic cartilage filled the defect to the level of the surrounding cartilage. Histologically, the grafts were viable, consisting mainly of cartilage, and showed a variable pattern of ingrowth. Three months after implantation empty defects with or without hyaluronan were filled primarily with fibrocartilaginous tissue. Defects treated with ectopic cartilage contained mixtures of fibrocartilaginous and hyaline cartilage. Sometimes a tidemark was observed in the new articular cartilage and the orientation of the cells resembled that of healthy articular cartilage. Subchondral bone repair was excellent. The modified O'Driscoll scores for empty defects without and with hyaluronan were 12.7 +/- 6.4 and 15.3 +/- 3.2; for treated defects scores were better (15.4 +/- 3.9 and 18.2 +/- 2.9). In this conceptual study the use of ectopic cartilage derived from periosteum appears to be a promising novel method for joint surface repair in rabbits.

  2. Blocking aggrecanase cleavage in the aggrecan interglobular domain abrogates cartilage erosion and promotes cartilage repair

    PubMed Central

    Little, Christopher B.; Meeker, Clare T.; Golub, Suzanne B.; Lawlor, Kate E.; Farmer, Pamela J.; Smith, Susan M.; Fosang, Amanda J.

    2007-01-01

    Aggrecan loss from cartilage in arthritis is mediated by aggrecanases. Aggrecanases cleave aggrecan preferentially in the chondroitin sulfate–2 (CS-2) domain and secondarily at the E373↓374A bond in the interglobular domain (IGD). However, IGD cleavage may be more deleterious for cartilage biomechanics because it releases the entire CS-containing portion of aggrecan. Recent studies identifying aggrecanase-2 (ADAMTS-5) as the predominant aggrecanase in mouse cartilage have not distinguished aggrecanolysis in the IGD from aggrecanolysis in the CS-2 domain. We generated aggrecan knockin mice with a mutation that rendered only the IGD resistant to aggrecanases in order to assess the contribution of this specific cleavage to cartilage pathology. The knockin mice were viable and fertile. Aggrecanase cleavage in the aggrecan IGD was not detected in knockin mouse cartilage in situ nor following digestion with ADAMTS-5 or treatment of cartilage explant cultures with IL-1α. Blocking cleavage in the IGD not only diminished aggrecan loss and cartilage erosion in surgically induced osteoarthritis and a model of inflammatory arthritis, but appeared to stimulate cartilage repair following acute inflammation. We conclude that blocking aggrecanolysis in the aggrecan IGD alone protects against cartilage erosion and may potentiate cartilage repair. PMID:17510707

  3. Mesenchymal stem-cell potential in cartilage repair: an update

    PubMed Central

    Mazor, M; Lespessailles, E; Coursier, R; Daniellou, R; Best, T M; Toumi, H

    2014-01-01

    Articular cartilage damage and subsequent degeneration are a frequent occurrence in synovial joints. Treatment of these lesions is a challenge because this tissue is incapable of quality repair and/or regeneration to its native state. Non-operative treatments endeavour to control symptoms and include anti-inflammatory medications, viscosupplementation, bracing, orthotics and activity modification. Classical surgical techniques for articular cartilage lesions are frequently insufficient in restoring normal anatomy and function and in many cases, it has not been possible to achieve the desired results. Consequently, researchers and clinicians are focusing on alternative methods for cartilage preservation and repair. Recently, cell-based therapy has become a key focus of tissue engineering research to achieve functional replacement of articular cartilage. The present manuscript is a brief review of stem cells and their potential in the treatment of early OA (i.e. articular cartilage pathology) and recent progress in the field. PMID:25353372

  4. Silk microfiber-reinforced silk hydrogel composites for functional cartilage tissue repair

    PubMed Central

    Yodmuang, Supansa; McNamara, Stephanie L.; Nover, Adam B.; Mandal, Biman B.; Agarwal, Monica; Kelly, Terri-Ann N.; Chao, Pen-hsiu Grace; Hung, Clark; Kaplan, David L.; Vunjak-Novakovic, Gordana

    2014-01-01

    Cartilage tissue lacks an intrinsic capacity for self-regeneration due to slow matrix turnover, a limited supply of mature chondrocytes and insufficient vasculature. Although cartilage tissue engineering has achieved some success using agarose as a scaffolding material, major challenges of agarose-based cartilage repair, including non-degradability, poor tissue–scaffold integration and limited processing capability, have prompted the search for an alternative biomaterial. In this study, silk fiber–hydrogel composites (SF–silk hydrogels) made from silk microfibers and silk hydrogels were investigated for their potential use as a support material for engineered cartilage. We demonstrated the use of 100% silk-based fiber–hydrogel composite scaffolds for the development of cartilage constructs with properties comparable to those made with agarose. Cartilage constructs with an equilibrium modulus in the native tissue range were fabricated by mimicking the collagen fiber and proteoglycan composite architecture of native cartilage using biocompatible, biodegradable silk fibroin from Bombyx mori. Excellent chondrocyte response was observed on SF–silk hydrogels, and fiber reinforcement resulted in the development of more mechanically robust constructs after 42 days in culture compared to silk hydrogels alone. Thus, we demonstrate the versatility of silk fibroin as a composite scaffolding material for use in cartilage tissue repair to create functional cartilage constructs that overcome the limitations of agarose biomaterials, and provide a much-needed alternative to the agarose standard. PMID:25281788

  5. The repair of full-thickness articular cartilage defects. Immune responses to reparative tissue formed by allogeneic growth plate chondrocyte implants

    SciTech Connect

    Kawabe, N.; Yoshinao, M. )

    1991-07-01

    Growth plate cartilage cultivated in vitro was attached with a fibrin clot to a full-thickness articular cartilage defect on knee joints in allogeneic New Zealand rabbits. The healing of the defects was assessed by gross examination, light microscopy, and immunologic analysis for 24 weeks. Immunologic assessment of cell-mediated immunity, cytotoxicity of a humoral antibody by a 51 chromium release assay, and immunofluorescence studies were carried out. During the first two weeks following grafting, healing was excellent in 11 of the 17 defects. From three to 24 weeks, 11 of 42 defects examined had good results. Host lymphocytes had accumulated around the allograft at two to 12 weeks. Most of the implanted cartilage grown in vitro died and was replaced by fibrous tissue. The immunologic studies suggested that the implanted cartilage began to degenerate two to three weeks after implantation partially because of a humoral immune response but more importantly because of cell-mediated cytotoxicity.

  6. Direct Human Cartilage Repair Using Three-Dimensional Bioprinting Technology

    PubMed Central

    Cui, Xiaofeng; Breitenkamp, Kurt; Finn, M.G.; Lotz, Martin

    2012-01-01

    Current cartilage tissue engineering strategies cannot as yet fabricate new tissue that is indistinguishable from native cartilage with respect to zonal organization, extracellular matrix composition, and mechanical properties. Integration of implants with surrounding native tissues is crucial for long-term stability and enhanced functionality. In this study, we developed a bioprinting system with simultaneous photopolymerization capable for three-dimensional (3D) cartilage tissue engineering. Poly(ethylene glycol) dimethacrylate (PEGDMA) with human chondrocytes were printed to repair defects in osteochondral plugs (3D biopaper) in layer-by-layer assembly. Compressive modulus of printed PEGDMA was 395.73±80.40 kPa, which was close to the range of the properties of native human articular cartilage. Printed human chondrocytes maintained the initially deposited positions due to simultaneous photopolymerization of surrounded biomaterial scaffold, which is ideal in precise cell distribution for anatomic cartilage engineering. Viability of printed human chondrocytes increased 26% in simultaneous polymerization than polymerized after printing. Printed cartilage implant attached firmly with surrounding tissue and greater proteoglycan deposition was observed at the interface of implant and native cartilage in Safranin-O staining. This is consistent with the enhanced interface failure strength during the culture assessed by push-out testing. Printed cartilage in 3D biopaper had elevated glycosaminoglycan (GAG) content comparing to that without biopaper when normalized to DNA. These observations were consistent with gene expression results. This study indicates the importance of direct cartilage repair and promising anatomic cartilage engineering using 3D bioprinting technology. PMID:22394017

  7. A vision on the future of articular cartilage repair.

    PubMed

    Cucchiarini, M; Madry, H; Guilak, F; Saris, D B; Stoddart, M J; Koon Wong, M; Roughley, P

    2014-05-06

    An AO Foundation (Davos, Switzerland) sponsored workshop "Cell Therapy in Cartilage Repair" from the Symposium "Where Science meets Clinics" (September 5-7, 2013, Davos) gathered leaders from medicine, science, industry, and regulatory organisations to debate the vision of cell therapy in articular cartilage repair and the measures that could be taken to narrow the gap between vision and current practice. Cell-based therapy is already in clinical use to enhance the repair of cartilage lesions, with procedures such as microfracture and articular chondrocyte implantation. However, even though long term follow up is good from a clinical perspective and some of the most rigorous randomised controlled trials in the regenerative medicine/orthopaedics field show beneficial effect, none of these options have proved successful in restoring the original articular cartilage structure and functionality in patients so far. With the remarkable recent advances in experimental research in cell biology (new sources for chondrocytes, stem cells), molecular biology (growth factors, genes), biomaterials, biomechanics, and translational science, a combined effort between scientists and clinicians with broad expertise may allow development of an improved cell therapy for cartilage repair. This position paper describes the current state of the art in the field to help define a procedure adapted to the clinical situation for upcoming translation in the patient.

  8. Hydrogels for the Repair of Articular Cartilage Defects

    PubMed Central

    Maher, Suzanne A.; Lowman, Anthony M.

    2011-01-01

    The repair of articular cartilage defects remains a significant challenge in orthopedic medicine. Hydrogels, three-dimensional polymer networks swollen in water, offer a unique opportunity to generate a functional cartilage substitute. Hydrogels can exhibit similar mechanical, swelling, and lubricating behavior to articular cartilage, and promote the chondrogenic phenotype by encapsulated cells. Hydrogels have been prepared from naturally derived and synthetic polymers, as cell-free implants and as tissue engineering scaffolds, and with controlled degradation profiles and release of stimulatory growth factors. Using hydrogels, cartilage tissue has been engineered in vitro that has similar mechanical properties to native cartilage. This review summarizes the advancements that have been made in determining the potential of hydrogels to replace damaged cartilage or support new tissue formation as a function of specific design parameters, such as the type of polymer, degradation profile, mechanical properties and loading regimen, source of cells, cell-seeding density, controlled release of growth factors, and strategies to cause integration with surrounding tissue. Some key challenges for clinical translation remain, including limited information on the mechanical properties of hydrogel implants or engineered tissue that are necessary to restore joint function, and the lack of emphasis on the ability of an implant to integrate in a stable way with the surrounding tissue. Future studies should address the factors that affect these issues, while using clinically relevant cell sources and rigorous models of repair. PMID:21510824

  9. Human cartilage repair with a photoreactive adhesive-hydrogel composite.

    PubMed

    Sharma, Blanka; Fermanian, Sara; Gibson, Matthew; Unterman, Shimon; Herzka, Daniel A; Cascio, Brett; Coburn, Jeannine; Hui, Alexander Y; Marcus, Norman; Gold, Garry E; Elisseeff, Jennifer H

    2013-01-01

    Surgical options for cartilage resurfacing may be significantly improved by advances and application of biomaterials that direct tissue repair. A poly(ethylene glycol) diacrylate (PEGDA) hydrogel was designed to support cartilage matrix production, with easy surgical application. A model in vitro system demonstrated deposition of cartilage-specific extracellular matrix in the hydrogel biomaterial and stimulation of adjacent cartilage tissue development by mesenchymal stem cells. For translation to the joint environment, a chondroitin sulfate adhesive was applied to covalently bond and adhere the hydrogel to cartilage and bone tissue in articular defects. After preclinical testing in a caprine model, a pilot clinical study was initiated where the biomaterials system was combined with standard microfracture surgery in 15 patients with focal cartilage defects on the medial femoral condyle. Control patients were treated with microfracture alone. Magnetic resonance imaging showed that treated patients achieved significantly higher levels of tissue fill compared to controls. Magnetic resonance spin-spin relaxation times (T(2)) showed decreasing water content and increased tissue organization over time. Treated patients had less pain compared with controls, whereas knee function [International Knee Documentation Committee (IKDC)] scores increased to similar levels between the groups over the 6 months evaluated. No major adverse events were observed over the study period. With further clinical testing, this practical biomaterials strategy has the potential to improve the treatment of articular cartilage defects. PMID:23303605

  10. Repair of the superior sulcus deformity using autogenous costal cartilage.

    PubMed

    Sutula, F C; Thomas, O

    1982-05-01

    Superior sulcus deformity is a late sequela of surgical anophthalmos. Many methods have been proposed to treat this difficult problem. A technique using autogenous costal cartilage that has resulted in satisfactory repair is presented. In addition to standard photographs and exophthalmometry measurements to follow these patients, a specific device to accurately measure orbital volume gain after operation was fashioned. PMID:7099560

  11. Increasing the Dose of Autologous Chondrocytes Improves Articular Cartilage Repair

    PubMed Central

    Guillén-García, Pedro; Rodríguez-Iñigo, Elena; Guillén-Vicente, Isabel; Caballero-Santos, Rosa; Guillén-Vicente, Marta; Abelow, Stephen; Giménez-Gallego, Guillermo

    2014-01-01

    Background: We hypothesized that implanting cells in a chondral defect at a density more similar to that of the intact cartilage could induce them to synthesize matrix with the features more similar to that of the uninjured one. Methods: We compared the implantation of different doses of chondrocytes: 1 million (n = 5), 5 million (n = 5), or 5 million mesenchymal cells (n = 5) in the femoral condyle of 15 sheep. Tissue generated by microfracture at the trochlea, and normal cartilage from a nearby region, processed as the tissues resulting from the implantation, were used as references. Histological and molecular (expression of type I and II collagens and aggrecan) studies were performed. Results: The features of the cartilage generated by implantation of mesenchymal cells and elicited by microfractures were similar and typical of a poor repair of the articular cartilage (presence of fibrocartilage, high expression of type I collagen and a low mRNA levels of type II collagen and aggrecan). Nevertheless, in the samples obtained from tissues generated by implantation of chondrocytes, hyaline-like cartilage, cell organization, low expression rates of type I collagen and high levels of mRNA corresponding to type II collagen and aggrecan were observed. These histological features, show less variability and are more similar to those of the normal cartilage used as control in the case of 5 million cells implantation than when 1 million cells were used. Conclusions: The implantation of autologous chondrocytes in type I/III collagen membranes at high density could be a promising tool to repair articular cartilage. PMID:26069691

  12. Articular cartilage repair with autologous bone marrow mesenchymal cells.

    PubMed

    Matsumoto, Tomiya; Okabe, Takahiro; Ikawa, Tesshu; Iida, Takahiro; Yasuda, Hiroyuki; Nakamura, Hiroaki; Wakitani, Shigeyuki

    2010-11-01

    Articular cartilage defects that do not repair spontaneously induce osteoarthritic changes in joints over a long period of observation. In this study, we examined the usefulness of transplanting culture-expanded bone marrow mesenchymal cells into osteochondral defects of joints with cartilage defects. First, we performed experiments on rabbits and up on obtaining good results proceeded to perform the experiments on humans. Macroscopic and histological repair with this method was good, and good clinical results were obtained although there was no significant difference with the control group. Recent reports have indicated that this procedure is comparable to autologous chondrocyte implantation, and concluded that it was a good procedure because it required one step less than that required by surgery, reduced costs for patients, and minimized donor site morbidity. Although some reports have previously shown that progenitor cells formed a tumor when implanted into immune-deficient mice after long term in vitro culture, the safety of the cell transplantation was confirmed by our clinical experience. Thus, this procedure is useful, effective, and safe, but the repaired tissues were not always hyaline cartilage. To obtain better repair with this procedure, treatment approaches using some growth factors during in vitro culture or gene transfection are being explored.

  13. Cartilage Repair Using Human Embryonic Stem Cell-Derived Chondroprogenitors

    PubMed Central

    Kapacee, Zoher; Peng, Jiang; Lu, Shibi; Lucas, Robert J.; Hardingham, Timothy E.

    2014-01-01

    In initial work, we developed a 14-day culture protocol under potential GMP, chemically defined conditions to generate chondroprogenitors from human embryonic stem cells (hESCs). The present study was undertaken to investigate the cartilage repair capacity of these cells. The chondrogenic protocol was optimized and validated with gene expression profiling. The protocol was also applied successfully to two lines of induced pluripotent stem cells (iPSCs). Chondrogenic cells derived from hESCs were encapsulated in fibrin gel and implanted in osteochondral defects in the patella groove of nude rats, and cartilage repair was evaluated by histomorphology and immunocytochemistry. Genes associated with chondrogenesis were upregulated during the protocol, and pluripotency-related genes were downregulated. Aggregation of chondrogenic cells was accompanied by high expression of SOX9 and strong staining with Safranin O. Culture with PluriSln1 was lethal for hESCs but was tolerated by hESC chondrogenic cells, and no OCT4-positive cells were detected in hESC chondrogenic cells. iPSCs were also shown to generate chondroprogenitors in this protocol. Repaired tissue in the defect area implanted with hESC-derived chondrogenic cells was stained for collagen II with little collagen I, but negligible collagen II was observed in the fibrin-only controls. Viable human cells were detected in the repair tissue at 12 weeks. The results show that chondrogenic cells derived from hESCs, using a chemically defined culture system, when implanted in focal defects were able to promote cartilage repair. This is a first step in evaluating these cells for clinical application for the treatment of cartilage lesions. PMID:25273540

  14. Transplantation of allogenic chondrocytes with chitosan hydrogel-demineralized bone matrix hybrid scaffold to repair rabbit cartilage injury.

    PubMed

    Man, Zhentao; Hu, Xiaoqing; Liu, Zhenlong; Huang, Hongjie; Meng, Qingyang; Zhang, Xin; Dai, Linghui; Zhang, Jiying; Fu, Xin; Duan, Xiaoning; Zhou, Chunyan; Ao, Yingfang

    2016-11-01

    Cartilage tissue engineering is the hotspot of cartilage repair. The allogenic chondrocytes appear to be a promising source of seed cells in cartilage tissue engineering. In this study, we aimed to transplant allogenic chondrocytes with chitosan hydrogel (CS)-demineralized bone matrix (DBM) hybrid scaffold (CS/DBM) to repair rabbit cartilage injury with one-step operation. After the CS/DBM scaffold was successfully fabricated, it showed that the porous CS filled the large pores of DBM, which improved the distribution of seed cells in the CS/DBM scaffold. The allogenic chondrocytes at second passage were transplanted with different scaffolds to repair rabbit cartilage injury. Twenty-four weeks after surgery, the cartilage defect in the CS/DBM group was successfully filled as shown by MRI. Moreover, the histological score of CS/DBM group was significantly higher than that of the other groups. On the aspect of biomechanical property, the regenerated cartilage in the CS/DBM group were superior to those in the other groups as determined by nanoindentation. Meanwhile, no obvious inflammatory response was observed after the transplantation of allogenic chondrocytes at 24 weeks post-surgery. Furtherly, gene expression profile for cells within the repair tissue was compared with the allogenic chondrocytes before transplantation using Agilent microarray and RT-qPCR. The results showed that some genes beneficial to cartilage regeneration, such as BMP-7, HGF, and IGF-1, were upregulated one month after transplantation. Consequently, our study demonstrated that the transplantation of allogenic chondrocytes with CS/DBM scaffold successfully repaired rabbit cartilage injury with only one-step operation, thereby providing new insights into cartilage tissue engineering. PMID:27636153

  15. International Cartilage Repair Society (ICRS) Recommended Guidelines for Histological Endpoints for Cartilage Repair Studies in Animal Models and Clinical Trials

    PubMed Central

    Hoemann, Caroline; Kandel, Rita; Roberts, Sally; Saris, Daniel B.F.; Creemers, Laura; Mainil-Varlet, Pierre; Méthot, Stephane; Hollander, Anthony P.; Buschmann, Michael D.

    2011-01-01

    Cartilage repair strategies aim to resurface a lesion with osteochondral tissue resembling native cartilage, but a variety of repair tissues are usually observed. Histology is an important structural outcome that could serve as an interim measure of efficacy in randomized controlled clinical studies. The purpose of this article is to propose guidelines for standardized histoprocessing and unbiased evaluation of animal tissues and human biopsies. Methods were compiled from a literature review, and illustrative data were added. In animal models, treatments are usually administered to acute defects created in healthy tissues, and the entire joint can be analyzed at multiple postoperative time points. In human clinical therapy, treatments are applied to developed lesions, and biopsies are obtained, usually from a subset of patients, at a specific time point. In striving to standardize evaluation of structural endpoints in cartilage repair studies, 5 variables should be controlled: 1) location of biopsy/sample section, 2) timing of biopsy/sample recovery, 3) histoprocessing, 4) staining, and 5) blinded evaluation with a proper control group. Histological scores, quantitative histomorphometry of repair tissue thickness, percentage of tissue staining for collagens and glycosaminoglycan, polarized light microscopy for collagen fibril organization, and subchondral bone integration/structure are all relevant outcome measures that can be collected and used to assess the efficacy of novel therapeutics. Standardized histology methods could improve statistical analyses, help interpret and validate noninvasive imaging outcomes, and permit cross-comparison between studies. Currently, there are no suitable substitutes for histology in evaluating repair tissue quality and cartilaginous character. PMID:26069577

  16. Evolution of Autologous Chondrocyte Repair and Comparison to Other Cartilage Repair Techniques

    PubMed Central

    Dewan, Ashvin K.; Gibson, Matthew A.; Elisseeff, Jennifer H.; Trice, Michael E.

    2014-01-01

    Articular cartilage defects have been addressed using microfracture, abrasion chondroplasty, or osteochondral grafting, but these strategies do not generate tissue that adequately recapitulates native cartilage. During the past 25 years, promising new strategies using assorted scaffolds and cell sources to induce chondrocyte expansion have emerged. We reviewed the evolution of autologous chondrocyte implantation and compared it to other cartilage repair techniques. Methods. We searched PubMed from 1949 to 2014 for the keywords “autologous chondrocyte implantation” (ACI) and “cartilage repair” in clinical trials, meta-analyses, and review articles. We analyzed these articles, their bibliographies, our experience, and cartilage regeneration textbooks. Results. Microfracture, abrasion chondroplasty, osteochondral grafting, ACI, and autologous matrix-induced chondrogenesis are distinguishable by cell source (including chondrocytes and stem cells) and associated scaffolds (natural or synthetic, hydrogels or membranes). ACI seems to be as good as, if not better than, microfracture for repairing large chondral defects in a young patient's knee as evaluated by multiple clinical indices and the quality of regenerated tissue. Conclusion. Although there is not enough evidence to determine the best repair technique, ACI is the most established cell-based treatment for full-thickness chondral defects in young patients. PMID:25210707

  17. Cartilage Repair With Autologous Bone Marrow Mesenchymal Stem Cell Transplantation

    PubMed Central

    Yamasaki, Shinya; Mera, Hisashi; Itokazu, Maki; Hashimoto, Yusuke

    2014-01-01

    Clinical trials of various procedures, including bone marrow stimulation, mosaicplasty, and autologous chondrocyte implantation, have been explored to treat articular cartilage defects. However, all of them have some demerits. We focused on autologous culture-expanded bone marrow mesenchymal stem cells (BMSC), which can proliferate without losing their capacity for differentiation. First, we transplanted BMSC into the defective articular cartilage of rabbit and succeeded in regenerating osteochondral tissue. We then applied this transplantation in humans. Our previous reports showed that treatment with BMSC relieves the clinical symptoms of chondral defects in the knee and elbow joint. We investigated the efficacy of BMSC for osteoarthritic knee treated with high tibial osteotomy, by comparing 12 BMSC-transplanted patients with 12 cell-free patients. At 16-month follow-up, although the difference in clinical improvement between both groups was not significant, the arthroscopic and histological grading score was better in the cell-transplanted group. At the over 10-year follow-up, Hospital for Special Surgery knee scores improved to 76 and 73 in the BMSC-transplanted and cell-free groups, respectively, which were better than preoperative scores. Additionally, neither tumors nor infections were observed in all patients, and in the clinical study, we have never observed hypertrophy of repaired tissue, thereby guaranteeing the clinical safety of this therapy. Although we have never observed calcification above the tidemark in rabbit model and human histologically, the repair cartilage was not completely hyaline cartilage. To elucidate the optimum conditions for cell therapy, other stem cells, culture conditions, growth factors, and gene transfection methods should be explored. PMID:26069698

  18. Optimization and translation of MSC-based hyaluronic acid hydrogels for cartilage repair

    NASA Astrophysics Data System (ADS)

    Erickson, Isaac E.

    2011-12-01

    Traumatic injury and disease disrupt the ability of cartilage to carry joint stresses and, without an innate regenerative response, often lead to degenerative changes towards the premature development of osteoarthritis. Surgical interventions have yet to restore long-term mechanical function. Towards this end, tissue engineering has been explored for the de novo formation of engineered cartilage as a biologic approach to cartilage repair. Research utilizing autologous chondrocytes has been promising, but clinical limitations in their yield have motivated research into the potential of mesenchymal stem cells (MSCs) as an alternative cell source. MSCs are multipotent cells that can differentiate towards a chondrocyte phenotype in a number of biomaterials, but no combination has successfully recapitulated the native mechanical function of healthy articular cartilage. The broad objective of this thesis was to establish an MSC-based tissue engineering approach worthy of clinical translation. Hydrogels are a common class of biomaterial used for cartilage tissue engineering and our initial work demonstrated the potential of a photo-polymerizable hyaluronic acid (HA) hydrogel to promote MSC chondrogenesis and improved construct maturation by optimizing macromer and MSC seeding density. The beneficial effects of dynamic compressive loading, high MSC density, and continuous mixing (orbital shaker) resulted in equilibrium modulus values over 1 MPa, well in range of native tissue. While compressive properties are crucial, clinical translation also demands that constructs stably integrate within a defect. We utilized a push-out testing modality to assess the in vitro integration of HA constructs within artificial cartilage defects. We established the necessity for in vitro pre-maturation of constructs before repair to achieve greater integration strength and compressive properties in situ. Combining high MSC density and gentle mixing resulted in integration strength over 500 k

  19. The Role of Tissue Engineering in Articular Cartilage Repair and Regeneration

    PubMed Central

    Zhang, Lijie; Hu, Jerry; Athanasiou, Kyriacos A.

    2011-01-01

    Articular cartilage repair and regeneration continue to be largely intractable due to the poor regenerative properties of this tissue. The field of articular cartilage tissue engineering, which aims to repair, regenerate, and/or improve injured or diseased articular cartilage functionality, has evoked intense interest and holds great potential for improving articular cartilage therapy. This review provides an overall description of the current state and progress in articular cartilage repair and regeneration. Traditional therapies and related problems are introduced. More importantly, a variety of promising cell sources, biocompatible tissue engineered scaffolds, scaffoldless techniques, growth factors, and mechanical stimuli used in current articular cartilage tissue engineering are reviewed. Finally, the technical and regulatory challenges of articular cartilage tissue engineering and possible future directions are discussed. PMID:20201770

  20. Repair and tissue engineering techniques for articular cartilage

    PubMed Central

    Makris, Eleftherios A.; Gomoll, Andreas H.; Malizos, Konstantinos N.; Hu, Jerry C.; Athanasiou, Kyriacos A.

    2015-01-01

    Chondral and osteochondral lesions due to injury or other pathology commonly result in the development of osteoarthritis, eventually leading to progressive total joint destruction. Although current progress suggests that biologic agents can delay the advancement of deterioration, such drugs are incapable of promoting tissue restoration. The limited ability of articular cartilage to regenerate renders joint arthroplasty an unavoidable surgical intervention. This Review describes current, widely used clinical repair techniques for resurfacing articular cartilage defects; short-term and long-term clinical outcomes of these techniques are discussed. Also reviewed is a developmental pipeline of regenerative biological products that over the next decade could revolutionize joint care by functionally healing articular cartilage. These products include cell-based and cell-free materials such as autologous and allogeneic cell-based approaches and multipotent and pluripotent stem-cell-based techniques. Central to these efforts is the prominent role that tissue engineering has in translating biological technology into clinical products; therefore, concomitant regulatory processes are also discussed. PMID:25247412

  1. Current perspectives in stem cell research for knee cartilage repair

    PubMed Central

    Orth, Patrick; Rey-Rico, Ana; Venkatesan, Jagadeesh K; Madry, Henning; Cucchiarini, Magali

    2014-01-01

    Protocols based on the delivery of stem cells are currently applied in patients, showing encouraging results for the treatment of articular cartilage lesions (focal defects, osteoarthritis). Yet, restoration of a fully functional cartilage surface (native structural organization and mechanical functions) especially in the knee joint has not been reported to date, showing the need for improved designs of clinical trials. Various sources of progenitor cells are now available, originating from adult tissues but also from embryonic or reprogrammed tissues, most of which have already been evaluated for their chondrogenic potential in culture and for their reparative properties in vivo upon implantation in relevant animal models of cartilage lesions. Nevertheless, particular attention will be needed regarding their safe clinical use and their potential to form a cartilaginous repair tissue of proper quality and functionality in the patient. Possible improvements may reside in the use of biological supplements in accordance with regulations, while some challenges remain in establishing standardized, effective procedures in the clinics. PMID:24520197

  2. The Challenge and the Promise of Bone Marrow Cells for Human Cartilage Repair

    PubMed Central

    2015-01-01

    The cartilage repair potential of bone marrow–derived stem cells has been well described. Harnessing this potential for human articular cartilage repair remains challenging. Accessing bone marrow repair cells through marrow stimulation techniques such as microfracture is readily achieved with generally good but inconsistent results. Animal and human studies show feasibility for ex vivo processing of bone marrow to isolate, concentrate, and culture mesenchymal stem cells. Nevertheless, it has been difficult to show consistent and clinically meaningful improvement using bone marrow cell preparations above what has been achieved with microfracture. Consequently, microfracture continues to be the simplest and most commonly used method to enhance repair of focal articular cartilage defects. Emerging preclinical work in the equine model suggests a role for enhancing marrow-stimulation techniques through the use of natural scaffolds such as autologous platelet enriched fibrin as well as optimization of joint biology through localized gene therapy to support cartilage repair. In contrast to joint replacement where inert materials of known mechanical properties are used, host biology determines the relative success, failure, and durability of cartilage repair. As such, development of personalized strategies to improve the quality and durability of bone marrow cell–based articular cartilage repair represent exciting new areas of inquiry. Continued advances in stem cell biology, scaffold technologies, and methods to delineate and enhance host biology, both systemically and within the joint, hold promise for harnessing the full power of bone marrow cells to facilitate cartilage repair and regeneration. PMID:27340515

  3. Flavonoid Compound Icariin Activates Hypoxia Inducible Factor-1α in Chondrocytes and Promotes Articular Cartilage Repair.

    PubMed

    Wang, Pengzhen; Zhang, Fengjie; He, Qiling; Wang, Jianqi; Shiu, Hoi Ting; Shu, Yinglan; Tsang, Wing Pui; Liang, Shuang; Zhao, Kai; Wan, Chao

    2016-01-01

    Articular cartilage has poor capability for repair following trauma or degenerative pathology due to avascular property, low cell density and migratory ability. Discovery of novel therapeutic approaches for articular cartilage repair remains a significant clinical need. Hypoxia is a hallmark for cartilage development and pathology. Hypoxia inducible factor-1alpha (HIF-1α) has been identified as a key mediator for chondrocytes to response to fluctuations of oxygen availability during cartilage development or repair. This suggests that HIF-1α may serve as a target for modulating chondrocyte functions. In this study, using phenotypic cellular screen assays, we identify that Icariin, an active flavonoid component from Herba Epimedii, activates HIF-1α expression in chondrocytes. We performed systemic in vitro and in vivo analysis to determine the roles of Icariin in regulation of chondrogenesis. Our results show that Icariin significantly increases hypoxia responsive element luciferase reporter activity, which is accompanied by increased accumulation and nuclear translocation of HIF-1α in murine chondrocytes. The phenotype is associated with inhibiting PHD activity through interaction between Icariin and iron ions. The upregulation of HIF-1α mRNA levels in chondrocytes persists during chondrogenic differentiation for 7 and 14 days. Icariin (10-6 M) increases the proliferation of chondrocytes or chondroprogenitors examined by MTT, BrdU incorporation or colony formation assays. Icariin enhances chondrogenic marker expression in a micromass culture including Sox9, collagen type 2 (Col2α1) and aggrecan as determined by real-time PCR and promotes extracellular matrix (ECM) synthesis indicated by Alcian blue staining. ELISA assays show dramatically increased production of aggrecan and hydroxyproline in Icariin-treated cultures at day 14 of chondrogenic differentiation as compared with the controls. Meanwhile, the expression of chondrocyte catabolic marker genes

  4. Flavonoid Compound Icariin Activates Hypoxia Inducible Factor-1α in Chondrocytes and Promotes Articular Cartilage Repair

    PubMed Central

    He, Qiling; Wang, Jianqi; Shiu, Hoi Ting; Shu, Yinglan; Tsang, Wing Pui; Liang, Shuang; Zhao, Kai; Wan, Chao

    2016-01-01

    Articular cartilage has poor capability for repair following trauma or degenerative pathology due to avascular property, low cell density and migratory ability. Discovery of novel therapeutic approaches for articular cartilage repair remains a significant clinical need. Hypoxia is a hallmark for cartilage development and pathology. Hypoxia inducible factor-1alpha (HIF-1α) has been identified as a key mediator for chondrocytes to response to fluctuations of oxygen availability during cartilage development or repair. This suggests that HIF-1α may serve as a target for modulating chondrocyte functions. In this study, using phenotypic cellular screen assays, we identify that Icariin, an active flavonoid component from Herba Epimedii, activates HIF-1α expression in chondrocytes. We performed systemic in vitro and in vivo analysis to determine the roles of Icariin in regulation of chondrogenesis. Our results show that Icariin significantly increases hypoxia responsive element luciferase reporter activity, which is accompanied by increased accumulation and nuclear translocation of HIF-1α in murine chondrocytes. The phenotype is associated with inhibiting PHD activity through interaction between Icariin and iron ions. The upregulation of HIF-1α mRNA levels in chondrocytes persists during chondrogenic differentiation for 7 and 14 days. Icariin (10−6 M) increases the proliferation of chondrocytes or chondroprogenitors examined by MTT, BrdU incorporation or colony formation assays. Icariin enhances chondrogenic marker expression in a micromass culture including Sox9, collagen type 2 (Col2α1) and aggrecan as determined by real-time PCR and promotes extracellular matrix (ECM) synthesis indicated by Alcian blue staining. ELISA assays show dramatically increased production of aggrecan and hydroxyproline in Icariin-treated cultures at day 14 of chondrogenic differentiation as compared with the controls. Meanwhile, the expression of chondrocyte catabolic marker genes

  5. Donor site morbidity after articular cartilage repair procedures: a review.

    PubMed

    Matricali, Giovanni A; Dereymaeker, Greta Ph E; Luyten, Frank P

    2010-10-01

    In order to perform an Osteochondral Autologous Transplantation (OAT) or an Autologous Chondrocyte Implantation (ACI), the integrity of healthy intact articular cartilage at a second location needs to be violated. This creates the possibility for donor site morbidity. Only recently have any publications addressed this issue. The aim of this manuscript is to review the current knowledge on donor site morbidity after an OAT or an ACI. Reports were identified by searching Medline and Pubmed up to March 2010. Donor site morbidity was described mostly considering a clinical outcome, both in a qualitative (parameters in history or physical examination) and/or quantitative way (knee status reported by means of a numerical score). An increasing rate of problems is noted when using quantitative instead of qualitative parameters, and when donor site morbidity is the focus of attention, affecting up to more than half of the patients, in particular for an OAT procedure. The decision to harvest an osteochondral or cartilage biopsy to perform a repair procedure should therefore be taken with caution. This also underscores the need for further research to identify safe donor sites or to develop techniques that eliminate the need for a formal biopsy ccompletely.

  6. Guidelines for the Design and Conduct of Clinical Studies in Knee Articular Cartilage Repair

    PubMed Central

    Mithoefer, Kai; Saris, Daniel B.F.; Farr, Jack; Kon, Elizaveta; Zaslav, Kenneth; Cole, Brian J.; Ranstam, Jonas; Yao, Jian; Shive, Matthew; Levine, David; Dalemans, Wilfried; Brittberg, Mats

    2011-01-01

    Objective: To summarize current clinical research practice and develop methodological standards for objective scientific evaluation of knee cartilage repair procedures and products. Design: A comprehensive literature review was performed of high-level original studies providing information relevant for the design of clinical studies on articular cartilage repair in the knee. Analysis of cartilage repair publications and synopses of ongoing trials were used to identify important criteria for the design, reporting, and interpretation of studies in this field. Results: Current literature reflects the methodological limitations of the scientific evidence available for articular cartilage repair. However, clinical trial databases of ongoing trials document a trend suggesting improved study designs and clinical evaluation methodology. Based on the current scientific information and standards of clinical care, detailed methodological recommendations were developed for the statistical study design, patient recruitment, control group considerations, study endpoint definition, documentation of results, use of validated patient-reported outcome instruments, and inclusion and exclusion criteria for the design and conduct of scientifically sound cartilage repair study protocols. A consensus statement among the International Cartilage Repair Society (ICRS) and contributing authors experienced in clinical trial design and implementation was achieved. Conclusions: High-quality clinical research methodology is critical for the optimal evaluation of current and new cartilage repair technologies. In addition to generally applicable principles for orthopedic study design, specific criteria and considerations apply to cartilage repair studies. Systematic application of these criteria and considerations can facilitate study designs that are scientifically rigorous, ethical, practical, and appropriate for the question(s) being addressed in any given cartilage repair research project

  7. Quantitative assessment of optical properties in healthy cartilage and repair tissue by optical coherence tomography and histology (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Jansen, Sanne M. A.; Cernohorsky, Paul; de Bruin, Daniel M.; van der Pol, Edwin; Savci-Heijink, Cemile D.; Strackee, Simon D.; Faber, Dirk J.; van Leeuwen, Ton G.

    2016-02-01

    Quantification of the OCT signal is an important step toward clinical implementation of a diagnostic tool in cartilage imaging. Discrimination of structural cartilage differences in patients with osteoarthritis is critical, yet challenging. This study assesses the variation in the optical attenuation coefficient (μOCT) between healthy cartilage, repair tissue, bone and layers within repair tissue in a controlled setting. OCT and histology was used to assess goat talus articular surfaces in which central osteochondral defects were created. Exact matches of OCT and histology were selected for research. μOCT measurements were taken from healthy cartilage, repair tissue and bone. Measured μOCT in healthy cartilage was higher compared to both repair tissue and bone tissue. Two possible mechanisms for the difference in attenuation were investigated. We studied morphological parameters in terms of nucleus count, nucleus size and inter-nucleus distance. Collagen content in healthy cartilage and repair tissue was assessed using polarization microscopy. Quantitative analysis of the nuclei did not demonstrate a difference in nucleus size and count between healthy cartilage and repair tissue. In healthy cartilage, cells were spaced farther apart and had a lower variation in local nuclear density compared to repair tissue. Polarization microscopy suggested higher collagen content in healthy cartilage compared to repair tissue. μOCT measurements can distinguish between healthy cartilage, repair tissue and bone. Results suggest that cartilage OCT attenuation measurements could be of great impact in clinical diagnostics of osteoarthritis.

  8. Improved quality of cartilage repair by bone marrow mesenchymal stem cells for treatment of an osteochondral defect in a cynomolgus macaque model

    PubMed Central

    Araki, Susumu; Imai, Shinji; Ishigaki, Hirohito; Mimura, Tomohiro; Nishizawa, Kazuya; Ueba, Hiroaki; Kumagai, Kousuke; Kubo, Mitsuhiko; Mori, Kanji; Ogasawara, Kazumasa; Matsusue, Yoshitaka

    2015-01-01

    Background and purpose Integration of repaired cartilage with surrounding native cartilage is a major challenge for successful tissue-engineering strategies of cartilage repair. We investigated whether incorporation of mesenchymal stem cells (MSCs) into the collagen scaffold improves integration and repair of cartilage defects in a cynomolgus macaque model. Methods Cynomolgus macaque bone marrow-derived MSCs were isolated and incorporated into type-I collagen gel. Full-thickness osteochondral defects (3 mm in diameter, 5 mm in depth) were created in the patellar groove of 36 knees of 18 macaques and were either left untreated (null group, n = 12), had collagen gel alone inserted (gel group, n = 12), or had collagen gel incorporating MSCs inserted (MSC group, n = 12). After 6, 12, and 24 weeks, the cartilage integration and tissue response were evaluated macroscopically and histologically (4 null, 4 gel, and 4 MSC knees at each time point). Results The gel group showed most cartilage-rich reparative tissue covering the defect, owing to formation of excessive cartilage extruding though the insufficient subchondral bone. Despite the fact that a lower amount of new cartilage was produced, the MSC group had better-quality cartilage with regular surface, seamless integration with neighboring naïve cartilage, and reconstruction of trabecular subchondral bone. Interpretation Even with intensive investigation, MSC-based cell therapy has not yet been established in experimental cartilage repair. Our model using cynomolgus macaques had optimized conditions, and the method using MSCs is superior to other experimental settings, allowing the possibility that the procedure might be introduced to future clinical practice. PMID:25175660

  9. Strategic Design and Fabrication of Engineered Scaffolds for Articular Cartilage Repair

    PubMed Central

    Izadifar, Zohreh; Chen, Xiongbiao; Kulyk, William

    2012-01-01

    Damage to articular cartilage can eventually lead to osteoarthritis (OA), a debilitating, degenerative joint disease that affects millions of people around the world. The limited natural healing ability of cartilage and the limitations of currently available therapies make treatment of cartilage defects a challenging clinical issue. Hopes have been raised for the repair of articular cartilage with the help of supportive structures, called scaffolds, created through tissue engineering (TE). Over the past two decades, different designs and fabrication techniques have been investigated for developing TE scaffolds suitable for the construction of transplantable artificial cartilage tissue substitutes. Advances in fabrication technologies now enable the strategic design of scaffolds with complex, biomimetic structures and properties. In particular, scaffolds with hybrid and/or biomimetic zonal designs have recently been developed for cartilage tissue engineering applications. This paper reviews critical aspects of the design of engineered scaffolds for articular cartilage repair as well as the available advanced fabrication techniques. In addition, recent studies on the design of hybrid and zonal scaffolds for use in cartilage tissue repair are highlighted. PMID:24955748

  10. Collagen/silk fibroin composite scaffold incorporated with PLGA microsphere for cartilage repair.

    PubMed

    Wang, Jianhua; Yang, Qiu; Cheng, Niangmei; Tao, Xiaojun; Zhang, Zhihua; Sun, Xiaomin; Zhang, Qiqing

    2016-04-01

    For cartilage repair, ideal scaffolds should mimic natural extracellular matrix (ECM) exhibiting excellent characteristics, such as biocompatibility, suitable porosity, and good cell affinity. This study aimed to prepare a collagen/silk fibroin composite scaffold incorporated with poly-lactic-co-glycolic acid (PLGA) microsphere that can be applied in repairing cartilage. To obtain optimum conditions for manufacturing a composite scaffold, a scaffold composed of different collagen-to-silk fibroin ratios was evaluated by determining porosity, water absorption, loss rate in hot water, and cell proliferation. Results suggested that the optimal ratio of collagen and silk fibroin composite scaffold was 7:3. The microstructure and morphological characteristics of the obtained scaffold were also examined through scanning electron microscopy and Fourier transform infrared spectroscopy. The results of in vitro fluorescence staining of bone marrow stromal cells revealed that collagen/silk fibroin composite scaffold enhanced cell proliferation without eliciting side effects. The prepared composite scaffold incorporated with PLGA microsphere was implanted in fully thick articular cartilage defects in rabbits. Collagen/silk fibroin composite scaffold with PLGA microspheres could enhance articular cartilage regeneration and integration between the repaired cartilage and the surrounding cartilage. Therefore, this composite will be a promising material for cartilage repair and regeneration.

  11. Collagen/silk fibroin composite scaffold incorporated with PLGA microsphere for cartilage repair.

    PubMed

    Wang, Jianhua; Yang, Qiu; Cheng, Niangmei; Tao, Xiaojun; Zhang, Zhihua; Sun, Xiaomin; Zhang, Qiqing

    2016-04-01

    For cartilage repair, ideal scaffolds should mimic natural extracellular matrix (ECM) exhibiting excellent characteristics, such as biocompatibility, suitable porosity, and good cell affinity. This study aimed to prepare a collagen/silk fibroin composite scaffold incorporated with poly-lactic-co-glycolic acid (PLGA) microsphere that can be applied in repairing cartilage. To obtain optimum conditions for manufacturing a composite scaffold, a scaffold composed of different collagen-to-silk fibroin ratios was evaluated by determining porosity, water absorption, loss rate in hot water, and cell proliferation. Results suggested that the optimal ratio of collagen and silk fibroin composite scaffold was 7:3. The microstructure and morphological characteristics of the obtained scaffold were also examined through scanning electron microscopy and Fourier transform infrared spectroscopy. The results of in vitro fluorescence staining of bone marrow stromal cells revealed that collagen/silk fibroin composite scaffold enhanced cell proliferation without eliciting side effects. The prepared composite scaffold incorporated with PLGA microsphere was implanted in fully thick articular cartilage defects in rabbits. Collagen/silk fibroin composite scaffold with PLGA microspheres could enhance articular cartilage regeneration and integration between the repaired cartilage and the surrounding cartilage. Therefore, this composite will be a promising material for cartilage repair and regeneration. PMID:26838900

  12. Current clinical therapies for cartilage repair, their limitation and the role of stem cells.

    PubMed

    Dhinsa, Baljinder S; Adesida, Adetola B

    2012-03-01

    The management of osteochondral defects of articular cartilage, whether from trauma or degenerative disease, continues to be a significant challenge for Orthopaedic surgeons. Current treatment options such as abrasion arthroplasty procedures, osteochondral transplantation and autologous chondrocyte implantation fail to produce repair tissue exhibiting the same mechanical and functional properties of native articular cartilage. This results in repair tissue that inevitably fails as it is unable to deal with the mechanical demands of articular cartilage, and does not prevent further degeneration of the native cartilage. Mesenchymal stem cells have been proposed as a potential source of cells for cell-based cartilage repair due to their ability to self-renew and undergo multi-lineage differentiation. This proposed procedure has the advantage of not requiring harvesting of cells from the joint surface, and its associated donor site morbidity, as well as having multiple possible adult donor tissues such as bone marrow, adipose tissue and synovium. Mesenchymal stem cells have multi-lineage potential, but can be stimulated to undergo chondrogenesis in the appropriate culture medium. As the majority of work with mesenchymal stem cell-derived articular cartilage repair has been carried out in vitro and in animal studies, more work still has to be done before this technique can be used for clinical purposes. This includes realizing the ideal method of harvesting mesenchymal stem cells, the culture medium to stimulate proliferation and differentiation, appropriate choice of scaffold incorporating growth factors directly or with gene therapy and integration of repair tissue with native tissue.

  13. Heterotopic autologous chondrocyte transplantation--a realistic approach to support articular cartilage repair?

    PubMed

    El Sayed, Karym; Haisch, Andreas; John, Thilo; Marzahn, Ulrike; Lohan, Anke; Müller, Riccarda D; Kohl, Benjamin; Ertel, Wolfgang; Stoelzel, Katharina; Schulze-Tanzil, Gundula

    2010-12-01

    Injured articular cartilage is limited in its capacity to heal. Autologous chondrocyte transplantation (ACT) is a suitable technique for cartilage repair, but it requires articular cartilage biopsies for sufficient autologous chondrocyte expansion in vitro. Hence, ACT is restricted by donor-site morbidity and autologous articular chondrocytes availability. The use of nonarticular heterotopic chondrocytes such as auricular, nasoseptal, or costal chondrocytes for ACT might overcome these limitations: heterotopic sources show lesser donor-site morbidity and a comparable extracellular cartilage matrix synthesis profile to articular cartilage. However, heterotopic (h)ACT poses a challenge. Particular tissue characteristics of heterotopic cartilage, divergent culturing peculiarities of heterotopic chondrocytes, and the advantages and drawbacks related to these diverse cartilage sources were critically discussed. Finally, available in vitro and in vivo experimental (h)ACT approaches were summarized. The quality of the cartilage engineered using heterotopic chondrocytes remains partly controversy due to the divergent methodologies and culture conditions used. While some encouraging in vivo results using (h)ACT have been demonstrated, standardized culturing protocols are strongly required. However, whether heterotopic chondrocytes implanted into joint cartilage defects maintain their particular tissue properties or can be adapted via tissue engineering strategies to fulfill regular articular cartilage functions requires further studies.

  14. Cell Therapy and Tissue Engineering Approaches for Cartilage Repair and/or Regeneration.

    PubMed

    Mardones, Rodrigo; Jofré, Claudio M; Minguell, José J

    2015-05-01

    Articular cartilage injuries caused by traumatic, mechanical and/or by progressive degeneration result in pain, swelling, subsequent loss of joint function and finally osteoarthritis. Due to the peculiar structure of the tissue (no blood supply), chondrocytes, the unique cellular phenotype in cartilage, receive their nutrition through diffusion from the synovial fluid and this limits their intrinsic capacity for healing. The first cellular avenue explored for cartilage repair involved the in situ transplantation of isolated chondrocytes. Latterly, an improved alternative for the above reparative strategy involved the infusion of mesenchymal stem cells (MSC), which in addition to a self-renewal capacity exhibit a differentiation potential to chondrocytes, as well as a capability to produce a vast array of growth factors, cytokines and extracellular matrix compounds involved in cartilage development. In addition to the above and foremost reparative options up till now in use, other therapeutic options have been developed, comprising the design of biomaterial substrates (scaffolds) capable of sustaining MSC attachment, proliferation and differentiation. The implantation of these engineered platforms, closely to the site of cartilage damage, may well facilitate the initiation of an 'in situ' cartilage reparation process. In this mini-review, we examined the timely and conceptual development of several cell-based methods, designed to repair/regenerate a damaged cartilage. In addition to the above described cartilage reparative options, other therapeutic alternatives still in progress are portrayed. PMID:26019754

  15. Cell Therapy and Tissue Engineering Approaches for Cartilage Repair and/or Regeneration

    PubMed Central

    Mardones, Rodrigo; Jofré, Claudio M.; Minguell, José J.

    2015-01-01

    Articular cartilage injuries caused by traumatic, mechanical and/or by progressive degeneration result in pain, swelling, subsequent loss of joint function and finally osteoarthritis. Due to the peculiar structure of the tissue (no blood supply), chondrocytes, the unique cellular phenotype in cartilage, receive their nutrition through diffusion from the synovial fluid and this limits their intrinsic capacity for healing. The first cellular avenue explored for cartilage repair involved the in situ transplantation of isolated chondrocytes. Latterly, an improved alternative for the above reparative strategy involved the infusion of mesenchymal stem cells (MSC), which in addition to a self-renewal capacity exhibit a differentiation potential to chondrocytes, as well as a capability to produce a vast array of growth factors, cytokines and extracellular matrix compounds involved in cartilage development. In addition to the above and foremost reparative options up till now in use, other therapeutic options have been developed, comprising the design of biomaterial substrates (scaffolds) capable of sustaining MSC attachment, proliferation and differentiation. The implantation of these engineered platforms, closely to the site of cartilage damage, may well facilitate the initiation of an ‘in situ’ cartilage reparation process. In this mini-review, we examined the timely and conceptual development of several cell-based methods, designed to repair/regenerate a damaged cartilage. In addition to the above described cartilage reparative options, other therapeutic alternatives still in progress are portrayed. PMID:26019754

  16. New perspectives for articular cartilage repair treatment through tissue engineering: A contemporary review

    PubMed Central

    Musumeci, Giuseppe; Castrogiovanni, Paola; Leonardi, Rosalia; Trovato, Francesca Maria; Szychlinska, Marta Anna; Di Giunta, Angelo; Loreto, Carla; Castorina, Sergio

    2014-01-01

    In this paper review we describe benefits and disadvantages of the established methods of cartilage regeneration that seem to have a better long-term effectiveness. We illustrated the anatomical aspect of the knee joint cartilage, the current state of cartilage tissue engineering, through mesenchymal stem cells and biomaterials, and in conclusion we provide a short overview on the rehabilitation after articular cartilage repair procedures. Adult articular cartilage has low capacity to repair itself, and thus even minor injuries may lead to progressive damage and osteoarthritic joint degeneration, resulting in significant pain and disability. Numerous efforts have been made to develop tissue-engineered grafts or patches to repair focal chondral and osteochondral defects, and to date several researchers aim to implement clinical application of cell-based therapies for cartilage repair. A literature review was conducted on PubMed, Scopus and Google Scholar using appropriate keywords, examining the current literature on the well-known tissue engineering methods for the treatment of knee osteoarthritis. PMID:24829869

  17. Dry arthroscopy with a retraction system for matrix-aided cartilage repair of patellar lesions.

    PubMed

    Sadlik, Boguslaw; Wiewiorski, Martin

    2014-02-01

    Several commercially available cartilage repair techniques use a natural or synthetic matrix to aid cartilage regeneration (e.g., autologous matrix-induced chondrogenesis or matrix-induced cartilage implantation). However, the use of matrix-aided techniques during conventional knee joint arthroscopy under continuous irrigation is challenging. Insertion and fixation of the matrix can be complicated by the presence of fluid and the confined patellofemoral joint space with limited access to the lesion. To overcome these issues, we developed a novel arthroscopic approach for matrix-aided cartilage repair of patellar lesions. This technical note describes the use of dry arthroscopy assisted by a minimally invasive retraction system. An autologous matrix-induced chondrogenesis procedure is used to illustrate this novel approach.

  18. The quality of healing: articular cartilage.

    PubMed

    Gomoll, Andreas H; Minas, Tom

    2014-05-01

    Articular cartilage lacks an intrinsic capacity for self-repair, and once damaged, it never heals. This creates an opportunity for surgical intervention, whether to stimulate a healing response that results in the formation of a lower-quality fibrocartilaginous scar or formal cartilage repair in the form of cartilage transplants. This article will review the nature of cartilage injury and discuss indications and techniques for repair.

  19. Advances in mesenchymal stem cell-based strategies for cartilage repair and regeneration.

    PubMed

    Toh, Wei Seong; Foldager, Casper Bindzus; Pei, Ming; Hui, James Hoi Po

    2014-10-01

    Significant research efforts have been undertaken in the last decade in the development of stem cell-based therapies for cartilage repair. Among the various stem cell sources, mesenchymal stem cells (MSCs) demonstrate great promise and clinical efficacy in cartilage regeneration. With a deeper understanding of stem cell biology, new therapeutics and new bioengineering approaches have emerged and showed potential for further developments. Of note, there has been a paradigm shift in applying MSCs for tissue regeneration from the use of stem cells for transplantation to the use of stem cell-derived matrix and secretome components as therapeutic tools and agents for cartilage regeneration. In this review, we will discuss the emerging role of MSCs in cartilage regeneration and the most recent advances in development of stem cell-based therapeutics for cartilage regeneration.

  20. Nanofibrous poly(3-hydroxybutyrate)/poly(3-hydroxyoctanoate) scaffolds provide a functional microenvironment for cartilage repair.

    PubMed

    Ching, Kuan Y; Andriotis, Orestis G; Li, Siwei; Basnett, Pooja; Su, Bo; Roy, Ipsita; Tare, Rahul S; Sengers, Bram G; Stolz, Martin

    2016-07-01

    Articular cartilage defects, when repaired ineffectively, often lead to further deterioration of the tissue, secondary osteoarthritis and, ultimately, joint replacement. Unfortunately, current surgical procedures are unable to restore normal cartilage function. Tissue engineering of cartilage provides promising strategies for the regeneration of damaged articular cartilage. As yet, there are still significant challenges that need to be overcome to match the long-term mechanical stability and durability of native cartilage. Using electrospinning of different blends of biodegradable poly(3-hydroxybutyrate)/poly(3-hydroxyoctanoate), we produced polymer scaffolds and optimised their structure, stiffness, degradation rates and biocompatibility. Scaffolds with a poly(3-hydroxybutyrate)/poly(3-hydroxyoctanoate) ratio of 1:0.25 exhibit randomly oriented fibres that closely mimic the collagen fibrillar meshwork of native cartilage and match the stiffness of native articular cartilage. Degradation of the scaffolds into products that could be easily removed from the body was indicated by changes in fibre structure, loss of molecular weight and a decrease in scaffold stiffness after one and four months. Histological and immunohistochemical analysis after three weeks of culture with human articular chondrocytes revealed a hyaline-like cartilage matrix. The ability to fine tune the ultrastructure and mechanical properties using different blends of poly(3-hydroxybutyrate)/poly(3-hydroxyoctanoate) allows to produce a cartilage repair kit for clinical use to reduce the risk of developing secondary osteoarthritis. We further suggest the development of a toolbox with tailor-made scaffolds for the repair of other tissues that require a 'guiding' structure to support the body's self-healing process.

  1. Nanofibrous poly(3-hydroxybutyrate)/poly(3-hydroxyoctanoate) scaffolds provide a functional microenvironment for cartilage repair.

    PubMed

    Ching, Kuan Y; Andriotis, Orestis G; Li, Siwei; Basnett, Pooja; Su, Bo; Roy, Ipsita; Tare, Rahul S; Sengers, Bram G; Stolz, Martin

    2016-07-01

    Articular cartilage defects, when repaired ineffectively, often lead to further deterioration of the tissue, secondary osteoarthritis and, ultimately, joint replacement. Unfortunately, current surgical procedures are unable to restore normal cartilage function. Tissue engineering of cartilage provides promising strategies for the regeneration of damaged articular cartilage. As yet, there are still significant challenges that need to be overcome to match the long-term mechanical stability and durability of native cartilage. Using electrospinning of different blends of biodegradable poly(3-hydroxybutyrate)/poly(3-hydroxyoctanoate), we produced polymer scaffolds and optimised their structure, stiffness, degradation rates and biocompatibility. Scaffolds with a poly(3-hydroxybutyrate)/poly(3-hydroxyoctanoate) ratio of 1:0.25 exhibit randomly oriented fibres that closely mimic the collagen fibrillar meshwork of native cartilage and match the stiffness of native articular cartilage. Degradation of the scaffolds into products that could be easily removed from the body was indicated by changes in fibre structure, loss of molecular weight and a decrease in scaffold stiffness after one and four months. Histological and immunohistochemical analysis after three weeks of culture with human articular chondrocytes revealed a hyaline-like cartilage matrix. The ability to fine tune the ultrastructure and mechanical properties using different blends of poly(3-hydroxybutyrate)/poly(3-hydroxyoctanoate) allows to produce a cartilage repair kit for clinical use to reduce the risk of developing secondary osteoarthritis. We further suggest the development of a toolbox with tailor-made scaffolds for the repair of other tissues that require a 'guiding' structure to support the body's self-healing process. PMID:27013217

  2. Differentiating the extent of cartilage repair in rabbit ears using nonlinear optical microscopy.

    PubMed

    Zhu, X Q; Xu, Y H; Liao, C X; Liu, W G; Cheng, K K; Chen, J X

    2015-11-01

    Nonlinear optical microscopy (NLOM) was used as a noninvasive and label-free tool to detect and quantify the extent of the cartilage recovery. Two cartilage injury models were established in the outer ears of rabbits that created a different extent of cartilage recovery based on the presence or absence of the perichondrium. High-resolution NLOM images were used to measure cartilage repair, specifically through spectral analysis and image texture. In contrast to a wound lacking a perichondrium, wounds with intact perichondria demonstrated significantly larger TPEF signals from cells and matrix, coarser texture indicating the more deposition of type I collagen. Spectral analysis of cells and matrix can reveal the matrix properties and cell growth. In addition, texture analysis of NLOM images showed significant differences in the distribution of cells and matrix of repaired tissues with or without perichondrium. Specifically, the decay length of autocorrelation coefficient based on TPEF images is 11.2 ± 1.1 in Wound 2 (with perichondrium) and 7.5 ± 2.0 in Wound 1 (without perichondrium), indicating coarser image texture and faster growth of cells in repaired tissues with perichondrium (p < 0.05). Moreover, the decay length of autocorrelation coefficient based on collagen SHG images also showed significant difference between Wound 2 and 1 (16.2 ± 1.2 vs. 12.2 ± 2.1, p < 0.05), indicating coarser image texture and faster deposition of collagen in repaired tissues with perichondrium (Wound 2). These findings suggest that NLOM is an ideal tool for studying cartilage repair, with potential applications in clinical medicine. NLOM can capture macromolecular details and distinguish between different extents of cartilage repair without the need for labelling agents.

  3. Epigenetic regulation in chondrocyte phenotype maintenance for cell-based cartilage repair

    PubMed Central

    Duan, Li; Liang, Yujie; Ma, Bin; Zhu, Weimin; Wang, Daping

    2015-01-01

    Loss of hyaline chondrocyte phenotype during the monolayer culture in vitro is a major obstacle for cell-based articular cartilage repair. Increasing evidence implicates an important role of the epigenetic regulation in maintaining the chondrocyte phenotype. DNA methylation, histone modifications and microRNAs have all been shown to contribute to chondrocyte dedifferentiation and hypertrophy. Moreover, the interplay among epigenetic regulators forms a complicated epigenetic network in regulating chondrocyte dedifferentiation. This review provides a detailed overview of the epigenetic regulation in maintaining the chondrocyte phenotype for chondrocyte-based cartilage repair. PMID:26807163

  4. Cell-Based Articular Cartilage Repair: The Link between Development and Regeneration

    PubMed Central

    Caldwell, Kenneth L.; Wang, Jinxi

    2014-01-01

    Context Clinical efforts to repair damaged articular cartilage (AC) currently face major obstacles due to limited intrinsic repair capacity of the tissue and unsuccessful biological interventions. This highlights a need for better therapeutic strategies. Evidence Acquisition Relevant articles were identified through a search of the PubMed database from January 1956 to August 2014 using the following keywords: articular cartilage repair, stem cell, cartilage tissue-engineering, synovium, and NFAT. Evidence Synthesis In both animals and humans, AC defects that penetrate into the subchondral bone marrow are mainly filled with fibrocartilaginous tissue through the differentiation of bone marrow mesenchymal stem cells (MSCs), followed by degeneration of repaired cartilage and osteoarthritis. Cell therapy and tissue engineering techniques using culture-expanded chondrocytes, bone marrow MSCs, or pluripotent stem cells with chondroinductive growth factors may generate cartilaginous tissue in AC defects but do not form hyaline cartilage-based articular surface because repair cells often lose chondrogenic activity or result in chondrocyte hypertrophy. The new evidence that AC and synovium develop from the same pool of precursors with similar gene profiles and that synovium-derived chondrocytes have stable chondrogenic activity has promoted use of synovium as a new cell source for AC repair. The recent finding that NFAT1 and NFAT2 transcription factors inhibit chondrocyte hypertrophy and maintain metabolic balance in AC is a significant advance in the field of AC repair. Conclusions The use of synovial MSCs and discovery of upstream transcriptional regulators that help maintain the AC phenotype have opened new avenues to improve the outcome of AC regeneration. PMID:25450846

  5. AMIC Cartilage Repair in a Professional Soccer Player.

    PubMed

    Bark, S; Riepenhof, H; Gille, J

    2012-01-01

    We report a case of a professional soccer player suffering from a traumatic cartilage lesion grade IV according to the Outerbridge classification at the femoral condyle treated with an enhanced microfracture technique (AMIC). Autologous Matrix-Induced Chondrogenesis (AMIC) is an innovative treatment for localized full-thickness cartilage defects combining the well-known microfracturing with collagen scaffold and fibrin glue. Because of the cartilage lesion (3 cm(2)), an AMIC procedure was performed followed by a rehabilitation program according to the protocols in the literature, (Steadman et al.; 2003). After 8 months of rehabilitation, the player returned to team training and after 10 months to competition. Altogether he returned to the same skill level for almost one year after the index operation. He is very satisfied with the clinical results after AMIC, which corresponds with the Lysholm score of 90 points at 12 months.

  6. Repair of experimentally produced defects in rabbit articular cartilage by autologous chondrocyte transplantation

    SciTech Connect

    Grande, D.A.; Pitman, M.I.; Peterson, L.; Menche, D.; Klein, M.

    1989-01-01

    Using the knee joints of New Zealand White rabbits, a baseline study was made to determine the intrinsic capability of cartilage for healing defects that do not fracture the subchondral plate. A second experiment examined the effect of autologous chondrocytes grown in vitro on the healing rate of these defects. To determine whether any of the reconstituted cartilage resulted from the chondrocyte graft, a third experiment was conducted involving grafts with chondrocytes that had been labeled prior to grafting with a nuclear tracer. Results were evaluated using both qualitative and quantitative light microscopy. Macroscopic results from grafted specimens displayed a marked decrease in synovitis and other degenerative changes. In defects that had received transplants, a significant amount of cartilage was reconstituted (82%) compared to ungrafted controls (18%). Autoradiography on reconstituted cartilage showed that there were labeled cells incorporated into the repair matrix.

  7. Characterization of a macroporous polyvinyl alcohol scaffold for the repair of focal articular cartilage defects.

    PubMed

    Ng, Kenneth W; Torzilli, Peter A; Warren, Russell F; Maher, Suzanne A

    2014-02-01

    Focal cartilage defects reduce the ability of articular cartilage to resist mechanical loading and provide lubrication during joint motion. The limitations in current surgical treatments have motivated the use of biocompatible scaffolds as a future treatment option. Here we describe a second generation macroporous, polyvinyl alcohol (PVA) scaffold with independently tunable morphological and mechanical properties. The compressive moduli of the PVA scaffold increased with increasing polymer concentration and applied compressive strain, with values in the range for human articular cartilage (HA  > 1000 kPa, EY  > 500 kPa). Scaffolds also possessed strain-dependent permeability and Poisson's ratio. The interconnected macroporous network was found to facilitate chondrocyte seeding and proliferation through the scaffold over one week in culture. Overall, these promising characteristics demonstrate the potential of this macroporous scaffold for future studies in focal cartilage defect repair.

  8. 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

  9. Single-step scaffold-based cartilage repair in the knee: A systematic review.

    PubMed

    Fischer, Stefan; Kisser, Agnes

    2016-12-01

    Chondral lesions are difficult-to-treat entities that often affect young and active people. Moreover, cartilage has limited intrinsic healing potential. The purpose of this systematic literature review was to analyse whether the single-step scaffold-based cartilage repair in combination with microfracturing (MFx) is more effective and safe in comparison to MFx alone. From the three identified studies, it seems that the single-step scaffold-assisted cartilage repair in combination with MFx leads to similar short- to medium-term (up to five years follow-up) results, compared to MFx alone. All of the studies have shown improvements regarding joint functionality, pain and partly quality of life. PMID:27408497

  10. Single-step scaffold-based cartilage repair in the knee: A systematic review.

    PubMed

    Fischer, Stefan; Kisser, Agnes

    2016-12-01

    Chondral lesions are difficult-to-treat entities that often affect young and active people. Moreover, cartilage has limited intrinsic healing potential. The purpose of this systematic literature review was to analyse whether the single-step scaffold-based cartilage repair in combination with microfracturing (MFx) is more effective and safe in comparison to MFx alone. From the three identified studies, it seems that the single-step scaffold-assisted cartilage repair in combination with MFx leads to similar short- to medium-term (up to five years follow-up) results, compared to MFx alone. All of the studies have shown improvements regarding joint functionality, pain and partly quality of life.

  11. Pilot Study of Cartilage Repair in the Knee Joint with Multiply Incised Chondral Allograft

    PubMed Central

    Vancsodi, Jozsef; Farkas, Boglarka; Fazekas, Adam; Nagy, Szilvia Anett; Bogner, Peter; Vermes, Csaba; Than, Peter

    2015-01-01

    Background Focal cartilage lesions in the knee joint have limited capacity to heal. Current animal experiments show that incisions of the deep zone of a cartilage allograft allow acceptable integration for the graft. Questions/Purposes We performed this clinical study to determine (1) if the multiply incised cartilage graft is surgically applicable for focal cartilage lesions, (2) whether this allograft has a potential to integrate to the repair site, and (3) if patients show clinical improvement. Patients and Methods Seven patients with 8 chondral lesions were enrolled into the study. Symptomatic lesions between 2 and 8 cm2 were accepted. Additional injuries were allowed but were addressed simultaneously. Grafts were tailored to match and the deep zone of the cartilage was multiply incised to augment the basal integration before securing in place. Rigorous postoperative physiotherapy followed. At 12 and 24 months the patients’ satisfaction were measured and serial magnetic resonance imaging (MRI) was performed in 6 patients. Results Following the implantations no adverse reaction occurred. MRI evaluation postoperatively showed the graft in place in 5 out of 6 patients. In 1 patient, MRI suggested partial delamination at 1 year and graft degeneration at 2 years. Short Form–36 health survey and the Lysholm knee score demonstrated a significant improvement in the first year; however, by 2 years there was a noticeable drop in the scores. Conclusions. Multiply incised pure chondral allograft used for cartilage repair appears to be a relatively safe method. Further studies are necessary to assess its potential in cartilage repair before its clinical use. PMID:26069710

  12. Cartilage from Nose Used to Repair Bum Knees

    MedlinePlus

    ... In small trial, patients were able to grow new cartilage in the joint To use the sharing features on this page, please enable JavaScript. (*this news item will not be available after 01/19/2017) Friday, October 21, 2016 THURSDAY, Oct. 20, 2016 ( ...

  13. Does Low-intensity pulsed ultrasound treatment repair articular cartilage injury? A rabbit model study

    PubMed Central

    2014-01-01

    Background Low-intensity pulsed ultrasound (LIPUS) regiment has been used to treat fractures with non-union and to promote bone union in general. The effect of LIPUS on articular cartilage metabolism has been characterized. Yet, the effect of LIPUS to repair articular cartilage injury remains unclear in vivo. Methods We designed a study to investigate the effect of LIPUS on articular cartilage repairing in a rabbit severe cartilage injury model. Eighteen rabbits were divided into three groups: Sham-operated group, operated group without-LIPUS-treatment, operated group with-LIPUS-treatment (a daily 20-minute treatment for 3 months). Full-thickness cartilage defects were surgically created on the right side distal femoral condyle without intending to penetrate into the subchondral bone, which mimicked severe chondral injury. MR images for experimental joints, morphology grading scale, and histopathological Mankin score were evaluated. Results The preliminary results showed that the operated groups with-LIPUS-treatment and without-LIPUS-treatment had significantly higher Mankin score and morphological grading scale compared with the sham-operated group. However, there was no significant difference between the with-LIPUS-treatment and without-LIPUS-treatment groups. Cartilage defects filled with proliferative tissue were observed in the with-LIPUS-treatment group grossly and under MR images, however which presented less up-take under Alcian blue stain. Furthermore, no new deposition of type II collagen or proliferation of chondrocyte was observed over the cartilage defect after LIPUS treatment. Conclusion LIPUS has no significant therapeutic potential in treating severe articular cartilage injury in our animal study. PMID:24507771

  14. Cartilage repair in osteoarthritic patients: utopia or real opportunity?

    PubMed

    Henrotin, Yves; Dubuc, Jean-Emile

    2009-01-01

    As medical advances lengthen average life expectancy, osteoarthritis (OA) will become a larger public health problem - not only because it is a manifestation of aging but also because it usually takes many years to reach clinical relevance. OA is already one of the ten most disabling diseases in industrialized countries. The huge financial burden emphasizes the acute need for new and more effective treatments for articular cartilage defects, especially since there are few disease modifying drugs or treatments for OA. There is no cure for OA and the management of OA is largely palliative, focusing on the alleviation of symptoms. Recent longitudinal non-controlled trials suggest that autologous chondrocyte transplantation techniques, which are indicated for young people with traumatic cartilage defects, could also be used in degenerative defects of elderly people with OA. This report discusses this therapeutic opportunity in view of some recently published data.

  15. Biology of platelet-rich plasma and its clinical application in cartilage repair

    PubMed Central

    2014-01-01

    Platelet-rich plasma (PRP) is an autologous concentrated cocktail of growth factors and inflammatory mediators, and has been considered to be potentially effective for cartilage repair. In addition, the fibrinogen in PRP may be activated to form a fibrin matrix to fill cartilage lesions, fulfilling the initial requirements of physiological wound healing. The anabolic, anti-inflammatory and scaffolding effects of PRP based on laboratory investigations, animal studies, and clinical trials are reviewed here. In vitro, PRP is found to stimulate cell proliferation and cartilaginous matrix production by chondrocytes and adult mesenchymal stem cells (MSCs), enhance matrix secretion by synoviocytes, mitigate IL-1β-induced inflammation, and provide a favorable substrate for MSCs. In preclinical studies, PRP has been used either as a gel to fill cartilage defects with variable results, or to slow the progression of arthritis in animal models with positive outcomes. Findings from current clinical trials suggest that PRP may have the potential to fill cartilage defects to enhance cartilage repair, attenuate symptoms of osteoarthritis and improve joint function, with an acceptable safety profile. Although current evidence appears to favor PRP over hyaluronan for the treatment of osteoarthritis, the efficacy of PRP therapy remains unpredictable owing to the highly heterogeneous nature of reported studies and the variable composition of the PRP preparations. Future studies are critical to elucidate the functional activity of individual PRP components in modulating specific pathogenic mechanisms. PMID:25164150

  16. Clinically Translatable Cell Tracking and Quantification by MRI in Cartilage Repair Using Superparamagnetic Iron Oxides

    PubMed Central

    van Buul, Gerben M.; Kotek, Gyula; Wielopolski, Piotr A.; Farrell, Eric; Bos, P. Koen; Weinans, Harrie; Grohnert, Anja U.; Jahr, Holger; Verhaar, Jan A. N.; Krestin, Gabriel P.

    2011-01-01

    Background Articular cartilage has very limited intrinsic regenerative capacity, making cell-based therapy a tempting approach for cartilage repair. Cell tracking can be a major step towards unraveling and improving the repair process of these therapies. We studied superparamagnetic iron oxides (SPIO) for labeling human bone marrow-derived mesenchymal stem cells (hBMSCs) regarding effectivity, cell viability, long term metabolic cell activity, chondrogenic differentiation and hBMSC secretion profile. We additionally examined the capacity of synovial cells to endocytose SPIO from dead, labeled cells, together with the use of magnetic resonance imaging (MRI) for intra-articular visualization and quantification of SPIO labeled cells. Methodology/Prinicipal Findings Efficacy and various safety aspects of SPIO cell labeling were determined using appropriate assays. Synovial SPIO re-uptake was investigated in vitro by co-labeling cells with SPIO and green fluorescent protein (GFP). MRI experiments were performed on a clinical 3.0T MRI scanner. Two cell-based cartilage repair techniques were mimicked for evaluating MRI traceability of labeled cells: intra-articular cell injection and cell implantation in cartilage defects. Cells were applied ex vivo or in vitro in an intra-articular environment and immediately scanned. SPIO labeling was effective and did not impair any of the studied safety aspects, including hBMSC secretion profile. SPIO from dead, labeled cells could be taken up by synovial cells. Both injected and implanted SPIO-labeled cells could accurately be visualized by MRI in a clinically relevant sized joint model using clinically applied cell doses. Finally, we quantified the amount of labeled cells seeded in cartilage defects using MR-based relaxometry. Conclusions SPIO labeling appears to be safe without influencing cell behavior. SPIO labeled cells can be visualized in an intra-articular environment and quantified when seeded in cartilage defects. PMID

  17. The benefits and limitations of animal models for translational research in cartilage repair.

    PubMed

    Moran, Conor J; Ramesh, Ashwanth; Brama, Pieter A J; O'Byrne, John M; O'Brien, Fergal J; Levingstone, Tanya J

    2016-12-01

    Much research is currently ongoing into new therapies for cartilage defect repair with new biomaterials frequently appearing which purport to have significant regenerative capacity. These biomaterials may be classified as medical devices, and as such must undergo rigorous testing before they are implanted in humans. A large part of this testing involves in vitro trials and biomechanical testing. However, in order to bridge the gap between the lab and the clinic, in vivo preclinical trials are required, and usually demanded by regulatory approval bodies. This review examines the in vivo models in current use for cartilage defect repair testing and the relevance of each in the context of generated results and applicability to bringing the device to clinical practice. Some of the preclinical models currently used include murine, leporine, ovine, caprine, porcine, canine, and equine models. Each of these has advantages and disadvantages in terms of animal husbandry, cartilage thickness, joint biomechanics and ethical and licencing issues. This review will examine the strengths and weaknesses of the various animal models currently in use in preclinical studies of cartilage repair. PMID:26915001

  18. The benefits and limitations of animal models for translational research in cartilage repair.

    PubMed

    Moran, Conor J; Ramesh, Ashwanth; Brama, Pieter A J; O'Byrne, John M; O'Brien, Fergal J; Levingstone, Tanya J

    2016-12-01

    Much research is currently ongoing into new therapies for cartilage defect repair with new biomaterials frequently appearing which purport to have significant regenerative capacity. These biomaterials may be classified as medical devices, and as such must undergo rigorous testing before they are implanted in humans. A large part of this testing involves in vitro trials and biomechanical testing. However, in order to bridge the gap between the lab and the clinic, in vivo preclinical trials are required, and usually demanded by regulatory approval bodies. This review examines the in vivo models in current use for cartilage defect repair testing and the relevance of each in the context of generated results and applicability to bringing the device to clinical practice. Some of the preclinical models currently used include murine, leporine, ovine, caprine, porcine, canine, and equine models. Each of these has advantages and disadvantages in terms of animal husbandry, cartilage thickness, joint biomechanics and ethical and licencing issues. This review will examine the strengths and weaknesses of the various animal models currently in use in preclinical studies of cartilage repair.

  19. Cartilage regeneration and repair testing in a surrogate large animal model.

    PubMed

    Simon, Timothy M; Aberman, Harold M

    2010-02-01

    The aging human population is experiencing increasing numbers of symptoms related to its degenerative articular cartilage (AC), which has stimulated the investigation of methods to regenerate or repair AC. However, the seemingly inherent limited capacity for AC to regenerate persists to confound the various repair treatment strategies proposed or studied. Animal models for testing AC implant devices and reparative materials are an important and required part of the Food and Drug Administration approval process. Although final testing is ultimately performed in humans, animal testing allows for a wider range of parameters and combinations of test materials subjected to all the biological interactions of a living system. We review here considerations, evaluations, and experiences with selection and use of animal models and describe two untreated lesion models useful for testing AC repair strategies. These created lesion models, one deep (6 mm and through the subchondral plate) the other shallow (to the level of the subchondral bone plate) were placed in the middle one-third of the medial femoral condyle of the knee joints of goats. At 1-year neither the deep nor the shallow full-thickness chondral defects generated a repair that duplicated natural AC. Moreover, progressive deleterious changes occurred in the AC surrounding the defects. There are challenges in translation from animals to humans as anatomy and structures are different and immobilization to protect delicate repairs can be difficult. The tissues potentially generated by proposed cartilage repair strategies must be compared with the spontaneous changes that occur in similarly created untreated lesions. The prevention of the secondary changes in the surrounding cartilage and subchondral bone described in this article should be addressed with the introduction of treatments for repairs of the articulating surface.

  20. Conserving Cartilage In Microtia Repair: The Modular Component Assembly Approach To Rebuilding A Human Ear

    PubMed Central

    Gandy, Jessica R.; Lemieux, Bryan; Foulad, Allen; Wong, Brian J.F.

    2016-01-01

    Objectives Current methods of microtia repair include carving an auricular framework from the costal synchondrosis. This requires considerable skill and may create a substantial donor site defect. Here, we present a modular component assembly (MCA) approach that minimizes the procedural difficulty and reduces the amount of cartilage to a single rib. Study Design Ex vivo study and survey Methods A single porcine rib was sectioned into multiple slices using a cartilage guillotine, cut into components outlined by 3D-printed templates, and assembled into an auricular scaffold. Electromechanical reshaping (EMR) was used to bend cartilage slices for creation of the helical rim. Chondrocyte viability was confirmed using confocal imaging. Ten surgeons reviewed the scaffold constructed with the MCA approach to evaluate aesthetics, relative stability, and clinical feasibility. Results An auricular framework with projection and curvature was fashioned from one rib. Surgeons found the MCA scaffold to meet minimal aesthetic and anatomic acceptability. When embedded under a covering, the region of the helix and anti-helix of the scaffold scored significantly higher on the assessment survey than that of an embedded alloplast implant (t-value=0.01). Otherwise, no difference was found between the embedded MCA and alloplast implants (t-value >0.05). EMR treated cartilage was found to be viable. Conclusion This study demonstrates that one rib can be used to create an aesthetic and durable framework for microtia repair. Precise assembly and the ability to obtain thin, uniform slices of cartilage were essential. This cartilage-sparing MCA approach may be an alternative to classic techniques. PMID:26720326

  1. Effect of porosities of bilayered porous scaffolds on spontaneous osteochondral repair in cartilage tissue engineering

    PubMed Central

    Dong, Jian; Ding, Jiandong

    2015-01-01

    Poly(lactide-co-glycolide)-bilayered scaffolds with the same porosity or different ones on the two layers were fabricated, and the porosity effect on in vivo repairing of the osteochondral defect was examined in a comparative way for the first time. The constructs of scaffolds and bone marrow-derived mesenchymal stem cells were implanted into pre-created osteochondral defects in the femoral condyle of New Zealand white rabbits. After 12 weeks, all experimental groups exhibited good cartilage repairing according to macroscopic appearance, cross-section view, haematoxylin and eosin staining, toluidine blue staining, immunohistochemical staining and real-time polymerase chain reaction of characteristic genes. The group of 92% porosity in the cartilage layer and 77% porosity in the bone layer resulted in the best efficacy, which was understood by more biomechanical mimicking of the natural cartilage and subchondral bone. This study illustrates unambiguously that cartilage tissue engineering allows for a wide range of scaffold porosity, yet some porosity group is optimal. It is also revealed that the biomechanical matching with the natural composite tissue should be taken into consideration in the design of practical biomaterials, which is especially important for porosities of a multi-compartment scaffold concerning connected tissues. PMID:26813511

  2. The vascularized periosteum flap as novel tissue engineering model for repair of cartilage defects

    PubMed Central

    Harhaus, Leila; Huang, Jung-Ju; Kao, Shu-Wei; Wu, Yen-Lin; Mackert, Gina Alicia; Höner, Bernd; Cheng, Ming-Huei; Kneser, Ulrich; Cheng, Chao-Min

    2015-01-01

    Periosteum is a promising tissue engineering scaffold in research of cartilage repair; so far however, periosteum transfers have not been realized successfully because of insufficient nourishment of the graft. In a translational approach we, for the first time, designed a vascularized periosteum flap as ‘independent’ biomaterial with its own blood supply to address this problem and to reconstruct circumscript cartilage defects. In six 3-month-old New Zealand rabbits, a critical size cartilage defect of the medial femur condyle was created and covered by a vascularized periosteum flap pedicled on the saphenous vessels. After 28 days, formation of newly built cartilage was assessed macroscopically, histologically and qualitatively via biomechanical compression testing, as well as on molecular biological level via immunohistochemistry. All wounds healed completely, all joints were stable and had full range of motion. All flaps survived and were perfused through their pulsating pedicles. They showed a stable attachment to the bone, although partially incomplete adherence. Hyaline cartilage with typical columnar cell distribution and positive Collagen II staining was formed in the transferred flaps. Biomechanical testing revealed a significantly higher maximum load than the positive control, but a low elasticity. This study proved that vascularization of the periosteum flap is the essential step for flap survival and enables the flap to transform into cartilage. Reconstruction of circumscript cartilage defects seems to be possible. Although these are the first results out of a pilot project, this technique, we believe, can have a wide range of potential applications and high relevance in the clinical field. PMID:25754287

  3. Use of chondral fragments for one stage cartilage repair: A systematic review

    PubMed Central

    Bonasia, Davide Edoardo; Marmotti, Antongiulio; Rosso, Federica; Collo, Gianluca; Rossi, Roberto

    2015-01-01

    AIM: To investigate the state of the art regarding Cartilage Autograft Implantation System (CAIS) or Particulated Juvenile Allograft Cartilage (PJAC). METHODS: The authors searched the English literature regarding CAIS and PJAC. The search strategy was: (particulated cartilage) OR autologous cartilage fragments. All basic science articles were included. Clinical articles with less than 10 patients treated and less than 6 mo of follow-up were excluded. With these criteria, a total of 17 articles were available for the present review. RESULTS: PJAC and CAIS are relatively novel techniques for cartilage repair. Good basic science evidence was described to support the concept. Although the preliminary clinical reports show encouraging results, clinical data are still limited, especially for CAIS. The indications for both techniques need to be precisely defined (age of the patients, size of the lesion, and involvement of the subchondral bone), together with other debated issues. CONCLUSION: In conclusion, the authors can state that encouraging preliminary results are available for both techniques. However, further studies are necessary to precisely determine the indications, surgical techniques, and long term outcomes for PJAC and CAIS. PMID:26716098

  4. Development and characterisation of a decellularised bovine osteochondral biomaterial for cartilage repair.

    PubMed

    Fermor, Hazel L; Russell, Serena L; Williams, Sophie; Fisher, John; Ingham, Eileen

    2015-05-01

    It is proposed that an acellular natural osteochondral scaffold will provide a successful repair material for the early intervention treatment of cartilage lesions, to prevent or slow the progression of cartilage deterioration to osteoarthritis. Here, we investigated the efficacy of methods for the decellularisation of bovine osteochondral plugs. The plugs were subject to four freeze/thaw cycles followed by two cycles of washes in hypotonic solution and low concentration (0.1% w/v) sodium dodecyl sulphate with protease inhibitors. Plugs were treated with nuclease (DNase and RNase) treatment followed by sterilization in peracetic acid. Full tissue decellularisation was achieved as confirmed by histological analysis and DNA quantification, however the resultant acellular matrix had reduced glycosaminoglycan content which led to an increased percent deformation of cartilage. Furthermore, the acellular scaffold was not reproducibly biocompatible. Additional terminal washes were included in the process to improve biocompatibility, however, this led to visible structural damage to the cartilage. This damage was found to be minimised by reducing the cut edge to cartilage area ratio through decellularisation of larger cuts of osteochondral tissue. PMID:25893393

  5. Communication Repair and Response Classes

    ERIC Educational Resources Information Center

    Meadan, Hedda; Halle, James W.

    2004-01-01

    A communicative repair has been defined as the ability to persist in communication and to modify, repeat, or revise a signal when the initial communication attempt failed. From an operant perspective, initial communicative acts and communicative repairs can be considered members of a response class in which each response produces the same outcome.…

  6. Evaluation of Cartilage Repair by Mesenchymal Stem Cells Seeded on a PEOT/PBT Scaffold in an Osteochondral Defect.

    PubMed

    Barron, V; Merghani, K; Shaw, G; Coleman, C M; Hayes, J S; Ansboro, S; Manian, A; O'Malley, G; Connolly, E; Nandakumar, A; van Blitterswijk, C A; Habibovic, P; Moroni, L; Shannon, F; Murphy, J M; Barry, F

    2015-09-01

    The main objective of this study was to evaluate the effectiveness of a mesenchymal stem cell (MSC)-seeded polyethylene-oxide-terephthalate/polybutylene-terephthalate (PEOT/PBT) scaffold for cartilage tissue repair in an osteochondral defect using a rabbit model. Material characterisation using scanning electron microscopy indicated that the scaffold had a 3D architecture characteristic of the additive manufacturing fabrication method, with a strut diameter of 296 ± 52 μm and a pore size of 512 ± 22 μm × 476 ± 25 μm × 180 ± 30 μm. In vitro optimisation revealed that the scaffold did not generate an adverse cell response, optimal cell loading conditions were achieved using 50 μg/ml fibronectin and a cell seeding density of 25 × 10(6) cells/ml and glycosaminoglycan (GAG) accumulation after 28 days culture in the presence of TGFβ3 indicated positive chondrogenesis. Cell-seeded scaffolds were implanted in osteochondral defects for 12 weeks, with cell-free scaffolds and empty defects employed as controls. On examination of toluidine blue staining for chondrogenesis and GAG accumulation, both the empty defect and the cell-seeded scaffold appeared to promote repair. However, the empty defect and the cell-free scaffold stained positive for collagen type I or fibrocartilage, while the cell-seeded scaffold stained positive for collagen type II indicative of hyaline cartilage and was statistically better than the cell-free scaffold in the blinded histological evaluation. In summary, MSCs in combination with a 3D PEOT/PBT scaffold created a reparative environment for cartilage repair.

  7. Iron oxide labelling of human mesenchymal stem cells in collagen hydrogels for articular cartilage repair.

    PubMed

    Heymer, Andrea; Haddad, Daniel; Weber, Meike; Gbureck, Uwe; Jakob, Peter M; Eulert, Jochen; Nöth, Ulrich

    2008-04-01

    For the development of new therapeutical cell-based strategies for articular cartilage repair, a reliable cell monitoring technique is required to track the cells in vivo non-invasively and repeatedly. We present a systematic and detailed study on the performance and biological impact of a simple and efficient labelling protocol for human mesenchymal stem cells (hMSCs). Commercially available very small superparamagnetic iron oxide particles (VSOPs) were used as magnetic resonance (MR) contrast agent. Iron uptake via endocytosis was confirmed histologically with prussian blue staining and quantified by mass spectrometry. Compared with unlabelled cells, VSOP-labelling did neither influence the viability nor the proliferation potential of hMSCs. Furthermore, iron incorporation did not affect hMSCs in undergoing adipogenic, osteogenic or chondrogenic differentiation, as demonstrated histologically and by gene expression analyses. The efficiency of the labelling protocol was assessed with high-resolution MR imaging at 11.7T. VSOP-labelled hMSCs were visualised in a collagen type I hydrogel, which is in clinical use for matrix-based articular cartilage repair. The presence of VSOP-labelled hMSCs was indicated by distinct hypointense spots in the MR images, as a result of iron specific loss of signal intensity. In summary, this labelling technique has great potential to visualise hMSCs and track their migration after transplantation for articular cartilage repair with MR imaging.

  8. Impact of guidance documents on translational large animal studies of cartilage repair.

    PubMed

    Pfeifer, Christian G; Fisher, Matthew B; Carey, James L; Mauck, Robert L

    2015-10-21

    Promising therapies for cartilage repair are translated through large animal models toward human application. To guide this work, regulatory agencies publish recommendations ("guidance documents") to direct pivotal large animal studies. These are meant to aid in study design, outline metrics for judging efficacy, and facilitate comparisons between studies. To determine the penetrance of these documents in the field, we synthesized the recommendations of the American Society for Testing and Materials, U.S. Food and Drug Administration, and European Medicines Agency into a scoring system and performed a systematic review of the past 20 years of preclinical cartilage repair studies. Our hypothesis was that the guidance documents would have a significant impact on how large animal cartilage repair studies were performed. A total of 114 publications meeting our inclusion criteria were reviewed for adherence to 24 categories extracted from the guidance documents, including 11 related to study design and description and 13 related to study outcomes. Overall, a weak positive trend was observed over time (P = 0.004, R(2) = 0.07, slope = 0.63%/year), with overall adherence (the sum of study descriptors and outcomes) ranging from 32 ± 16% to 58 ± 14% in any individual year. There was no impact of the publication of the guidance documents on adherence (P = 0.264 to 0.50). Given that improved adherence would expedite translation, we discuss the reasons for poor adherence and outline approaches to increase and promote their more widespread adoption.

  9. Articular chondrocyte culturing for cell-based cartilage repair: needs and perspectives.

    PubMed

    Giannoni, Paolo; Cancedda, Ranieri

    2006-01-01

    Articular cartilage displays a limited capacity of self-regeneration after injury. Thus, the biology of this tissue and its cellular components - the chondrocytes - has become the focus of several investigations, driven by tissue engineering and the basic and clinical research fields, aiming to ameliorate the present clinical approaches to cartilage repair. In this work, we present a brief recapitulation of the events that lead to cartilage development during the skeletal embryonal growth. The intrinsic phenotypic plasticity of the mesenchymal precursors and the adult chondrocytes is evaluated, dependent on the cell source, its physiopathological state, and as a function of the donor's age. The phenotypic changes induced by the basic culturing techniques are also taken into account, thus highlighting the phenotypic plasticity of the chondrocyte as the main property which could couple the differentiation process to the repair process. Chondrocyte proliferation and the contemporary maintenance of the chondrogenic differentiation potential are regarded as the two primary goals to be achieved in order to fulfill the quantitative needs of the clinical applications and the qualitative requirements of a properly repaired tissue. In this light, the effects of several growth factors and medium supplements are investigated. Finally, the latest improvements in culturing conditions and their possible clinical applications are presented as well.

  10. Zone-specific integrated cartilage repair using a scaffold-free tissue engineered construct derived from allogenic synovial mesenchymal stem cells: Biomechanical and histological assessments.

    PubMed

    Fujie, Hiromichi; Nansai, Ryosuke; Ando, Wataru; Shimomura, Kazunori; Moriguchi, Yu; Hart, David A; Nakamura, Norimasa

    2015-11-26

    The purpose of the present study was to investigate the zone-specific integration properties of articular cartilage defects treated in vivo with scaffold-free three-dimensional tissue-engineered constructs (TECs) derived from allogenic synovial mesenchymal stem cells (MSCs) in a porcine model. The TEC derived from the synovial MSCs was implanted into chondral defects in the medial femoral condyle of the knee. The integration boundary of repair tissue with the adjacent host cartilage was morphologically and biomechanically evaluated at 6 months post-implantation. Histological assessments showed that the repair tissue in each zone was well integrated with the adjacent host cartilage, with an apparent secure continuity of the extracellular matrix. There were no significant differences in histological scores between the integration boundary and the center of the repair tissue at every zone. Nonetheless, in all the specimens subjected to mechanical testing, failure occurred at the integration boundary. The average tensile strength of the integration boundary vs normal cartilage was 0.6 vs 4.9, 3.0 vs 12.6, and 5.5 vs 12.8MPa at the superficial, middle, and deep layers, respectively. Thus, these results indicate the most fragile point in the repair tissue remained at the integration boundary in spite of the apparent secure tissue continuity and equivalent histological quality with the center of the repair tissue. Such tissue vulnerability at the surface integration boundary could affect the long-term durability of the tissue repair, and thus, special consideration will be needed in the post-operative rehabilitation programming to enhance the longevity of such repair tissues in response to normal knee loading.

  11. Epidemiology and imaging of the subchondral bone in articular cartilage repair.

    PubMed

    Menetrey, Jacques; Unno-Veith, Florence; Madry, Henning; Van Breuseghem, Iwan

    2010-04-01

    Articular cartilage and the subchondral bone act as a functional unit. Following trauma, osteochondritis dissecans, osteonecrosis or osteoarthritis, this intimate connection may become disrupted. Osteochondral defects-the type of defects that extend into the subchondral bone-account for about 5% of all articular cartilage lesions. They are very often caused by trauma, in about one-third of the cases by osteoarthritis and rarely by osteochondritis dissecans. Osteochondral defects are predominantly located on the medial femoral condyle and also on the patella. Frequently, they are associated with lesions of the menisci or the anterior cruciate ligament. Because of the close relationship between the articular cartilage and the subchondral bone, imaging of cartilage defects or cartilage repair should also focus on the subchondral bone. Magnetic resonance imaging is currently considered to be the key modality for the evaluation of cartilage and underlying subchondral bone. However, the choice of imaging technique also depends on the nature of the disease that caused the subchondral bone lesion. For example, radiography is still the golden standard for imaging features of osteoarthritis. Bone scintigraphy is one of the most valuable techniques for early diagnosis of spontaneous osteonecrosis about the knee. A CT scan is a useful technique to rule out a possible depression of the subchondral bone plate, whereas a CT arthrography is highly accurate to evaluate the stability of the osteochondral fragment in osteochondritis dissecans. Particularly for the problem of subchondral bone lesions, image evaluation methods need to be refined for adequate and reproducible analysis. This article highlights recent studies on the epidemiology and imaging of the subchondral bone, with an emphasis on magnetic resonance imaging.

  12. Influence of acupuncture in treatment of knee osteoarthritis and cartilage repairing

    PubMed Central

    Zhang, Yan; Bao, Fei; Wang, Yan; Wu, Zhihong

    2016-01-01

    As two major non-operative methods, physiotherapy and acupuncture have been proved to be safe and effective in osteoarthritis (OA) treatment. However, only a little study focused on functions of both methods on cartilage repairing. The main goal of this research is to prove and compare effectiveness of acupuncture and physiotherapy on OA, and to explore their possible efficacy on cartilage repairing. One hundred knees of 50 participants with knee osteoarthritis (KOA) were randomly divided into acupuncture group and physiotherapy group. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was used to evaluate the motor function of knee joints, followed by MRI scanning to measure T2 values in ten cartilage sub-regions in tibiofemoral joints. Significant lower scores of total WOMAC and three subscales on the 4th weekend were observed in both groups than those of the baseline (P < 0.01). For acupuncture group, scores of total WOMAC and three subscales for pain, stiffness and physical function on 4th weekend were significantly lower than those of the physiotherapy group (P < 0.01 and P < 0.05). T2 values in anterior medial tibial sub-region (MTa) and anterior lateral tibial sub-region (LTa) were significantly lower in acupuncture group on 4th weekend than those of the baseline (P < 0.05). No significant difference in T2 values was detected in physiotherapy group. These results indicate that acupuncture represents certain clinical effect on KOA which is superior compared with physiotherapy, and hint the possible roles of acupuncture in promoting cartilage repairing. PMID:27725880

  13. FUNCTIONAL CARTILAGE MRI T2 MAPPING: EVALUATING THE EFFECT OF AGE AND TRAINING ON KNEE CARTILAGE RESPONSE TO RUNNING

    PubMed Central

    Mosher, Timothy J.; Liu, Yi; Torok, Collin M.

    2009-01-01

    Objective To characterize effects of age and physical activity level on cartilage thickness and T2 response immediately after running. Design Institutional review board approval was obtained and all subjects provided informed consent prior to study participation. Cartilage thickness and MRI T2 values of 22 marathon runners and 15 sedentary controls were compared before and after 30 minutes of running. Runner and control groups were stratified by age ≤ 45 and ≥ 46 years. Multi-echo (TR/TE 1500 ms/9 –109 ms) MR images obtained using a 3.0 T scanner were used to calculate thickness and T2 values from the central femoral and tibial cartilage. Baseline cartilage T2 values, and change in cartilage thickness and T2 values after running were compared between the four groups using 1-way ANOVA. Results After running MRI T2 values decreased in superficial femoral (2 ms to 4 ms) and tibial (1 ms to 3 ms) cartilage along with a decrease in cartilage thickness: (femoral: 4% to 8%, tibial: 0% to 12%). Smaller decrease in cartilage t2 values were observed in the middle zone of cartilage, and no change was observed in the deepest layer. There was no difference cartilage deformation or T2 response to running as a function of age or level of physical activity. Conclusions Running results in a measurable decrease in cartilage thickness and MRI T2 values of superficial cartilage consistent with greater compressibility of the superficial cartilage layer. Age and level of physical activity did not alter the T2 response to running. PMID:19948266

  14. Characterization of Chondrocyte Scaffold Carriers for Cell-based Gene Therapy in Articular Cartilage Repair

    PubMed Central

    Shui, Wei; Yin, Liangjun; Luo, Jeffrey; Li, Ruidong; Zhang, Wenwen; Zhang, Jiye; Huang, Wei; Hu, Ning; Liang, Xi; Deng, Zhong-Liang; Hu, Zhenming; Shi, Lewis; Luu, Hue H.; Haydon, Rex C.; He, Tong-Chuan; Ho, Sherwin

    2014-01-01

    Articular cartilage lesions in the knee are common injuries. Chondrocyte transplant represents a promising therapeutic modality for articular cartilage injuries. Here, we characterize the viability and transgene expression of articular chondrocytes cultured in 3-D scaffolds provided by four types of carriers. Articular chondrocytes are isolated from rabbit knees and cultured in four types of scaffolds: type I collagen sponge, fibrin glue, hyaluronan, and Open-cell PolyLactic Acid (OPLA). The cultured cells are transduced with adenovirus expressing green fluorescence protein (AdGFP) and luciferase (AdGL3-Luc). The viability and gene expression in the chondrocytes are determined with fluorescence microscopy and luciferase assay. Cartilage matrix production is assessed by Alcian blue staining. Rabbit articular chondrocytes are effectively infected by AdGFP and exhibited sustained GFP expression. All tested scaffolds support the survival and gene expression of the infected chondrocytes. However, the highest transgene expression is observed in the OPLA carrier. At four weeks, Alcian blue-positive matrix materials are readily detected in OPLA cultures. Thus, our results indicate that, while all tested carriers can support the survival of chondrocytes, OPLA supports the highest transgene expression and is the most conductive scaffold for matrix production, suggesting that OPLA may be a suitable scaffold for cell-based gene therapy of articular cartilage repairs. PMID:23629940

  15. A preclinical evaluation of an autologous living hyaline-like cartilaginous graft for articular cartilage repair: a pilot study

    PubMed Central

    Peck, Yvonne; He, Pengfei; Chilla, Geetha Soujanya V. N.; Poh, Chueh Loo; Wang, Dong-An

    2015-01-01

    In this pilot study, an autologous synthetic scaffold-free construct with hyaline quality, termed living hyaline cartilaginous graft (LhCG), was applied for treating cartilage lesions. Implantation of autologous LhCG was done at load-bearing regions of the knees in skeletally mature mini-pigs for 6 months. Over the course of this study, significant radiographical improvement in LhCG treated sites was observed via magnetic resonance imaging. Furthermore, macroscopic repair was effected by LhCG at endpoint. Microscopic inspection revealed that LhCG engraftment restored cartilage thickness, promoted integration with surrounding native cartilage, produced abundant cartilage-specific matrix molecules, and re-established an intact superficial tangential zone. Importantly, the repair efficacy of LhCG was quantitatively shown to be comparable to native, unaffected cartilage in terms of biochemical composition and biomechanical properties. There were no complications related to the donor site of cartilage biopsy. Collectively, these results imply that LhCG engraftment may be a viable approach for articular cartilage repair. PMID:26549401

  16. An Autologous Bone Marrow Mesenchymal Stem Cell–Derived Extracellular Matrix Scaffold Applied with Bone Marrow Stimulation for Cartilage Repair

    PubMed Central

    Tang, Cheng; Jin, Chengzhe; Du, Xiaotao; Yan, Chao; Min, Byoung-Hyun; Xu, Yan

    2014-01-01

    Purpose: It is well known that implanting a bioactive scaffold into a cartilage defect site can enhance cartilage repair after bone marrow stimulation (BMS). However, most of the current scaffolds are derived from xenogenous tissue and/or artificial polymers. The implantation of these scaffolds adds risks of pathogen transmission, undesirable inflammation, and other immunological reactions, as well as ethical issues in clinical practice. The current study was undertaken to evaluate the effectiveness of implanting autologous bone marrow mesenchymal stem cell–derived extracellular matrix (aBMSC-dECM) scaffolds after BMS for cartilage repair. Methods: Full osteochondral defects were performed on the trochlear groove of both knees in 24 rabbits. One group underwent BMS only in the right knee (the BMS group), and the other group was treated by implantation of the aBMSC-dECM scaffold after BMS in the left knee (the aBMSC-dECM scaffold group). Results: Better repair of cartilage defects was observed in the aBMSC-dECM scaffold group than in the BMS group according to gross observation, histological assessments, immunohistochemistry, and chemical assay. The glycosaminoglycan and DNA content, the distribution of proteoglycan, and the distribution and arrangement of type II and I collagen fibers in the repaired tissue in the aBMSC-dECM scaffold group at 12 weeks after surgery were similar to that surrounding normal hyaline cartilage. Conclusions: Implanting aBMSC-dECM scaffolds can enhance the therapeutic effect of BMS on articular cartilage repair, and this combination treatment is a potential method for successful articular cartilage repair. PMID:24666429

  17. Synovial fluid hyaluronan mediates MSC attachment to cartilage, a potential novel mechanism contributing to cartilage repair in osteoarthritis using knee joint distraction

    PubMed Central

    Mastbergen, Simon C; Jones, Elena; Calder, Stuart J; Lafeber, Floris P J G; McGonagle, Dennis

    2016-01-01

    Objectives Knee joint distraction (KJD) is a novel, but poorly understood, treatment for osteoarthritis (OA) associated with remarkable ‘spontaneous’ cartilage repair in which resident synovial fluid (SF) multipotential mesenchymal stromal cells (MSCs) may play a role. We hypothesised that SF hyaluronic acid (HA) inhibited the initial interaction between MSCs and cartilage, a key first step to integration, and postulate that KJD environment favoured MSC/cartilage interactions. Methods Attachment of dual-labelled SF-MSCs were assessed in a novel in vitro human cartilage model using OA and rheumatoid arthritic (RA) SF. SF was digested with hyaluronidase (hyase) and its effect on adhesion was observed using confocal microscopy. MRI and microscopy were used to image autologous dual-labelled MSCs in an in vivo canine model of KJD. SF-HA was investigated using gel electrophoresis and densitometry. Results Osteoarthritic-synovial fluid (OA-SF) and purified high molecular weight (MW) HA inhibited SF-MSC adhesion to plastic, while hyase treatment of OA-SF but not RA-SF significantly increased MSC adhesion to cartilage (3.7-fold, p<0.05) These differences were linked to the SF mediated HA-coat which was larger in OA-SF than in RA-SF. OA-SF contained >9 MDa HA and this correlated with increases in adhesion (r=0.880). In the canine KJD model, MSC adhesion to cartilage was evident and also dependent on HA MW. Conclusions These findings highlight an unappreciated role of SF-HA on MSC interactions and provide proof of concept that endogenous SF-MSCs are capable of adhering to cartilage in a favourable biochemical and biomechanical environment in OA distracted joints, offering novel one-stage strategies towards joint repair. PMID:25948596

  18. In Vivo Evaluation of a Novel Oriented Scaffold-BMSC Construct for Enhancing Full-Thickness Articular Cartilage Repair in a Rabbit Model

    PubMed Central

    Pan, Weimin; Liu, Jian; Sun, Wei

    2015-01-01

    Tissue engineering (TE) has been proven usefulness in cartilage defect repair. For effective cartilage repair, the structural orientation of the cartilage scaffold should mimic that of native articular cartilage, as this orientation is closely linked to cartilage mechanical functions. Using thermal-induced phase separation (TIPS) technology, we have fabricated an oriented cartilage extracellular matrix (ECM)-derived scaffold with a Young's modulus value 3 times higher than that of a random scaffold. In this study, we test the effectiveness of bone mesenchymal stem cell (BMSC)-scaffold constructs (cell-oriented and random) in repairing full-thickness articular cartilage defects in rabbits. While histological and immunohistochemical analyses revealed efficient cartilage regeneration and cartilaginous matrix secretion at 6 and 12 weeks after transplantation in both groups, the biochemical properties (levels of DNA, GAG, and collagen) and biomechanical values in the oriented scaffold group were higher than that in random group at early time points after implantation. While these differences were not evident at 24 weeks, the biochemical and biomechanical properties of the regenerated cartilage in the oriented scaffold-BMSC construct group were similar to that of native cartilage. These results demonstrate that an oriented scaffold, in combination with differentiated BMSCs can successfully repair full-thickness articular cartilage defects in rabbits, and produce cartilage enhanced biomechanical properties. PMID:26695629

  19. Possible role of the Ec peptide of IGF-1Ec in cartilage repair

    PubMed Central

    Armakolas, Nikolaos; Dimakakos, Andreas; Armakolas, Athanasios; Antonopoulos, Athanasios; Koutsilieris, Michael

    2016-01-01

    The Ec peptide (PEc) of insulin-like growth factor 1 Ec (IGF-1Ec) induces human mesenchymal stem cell (hMSC) mobilization and activates extracellular signal-regulated kinase 1/2 (ERK 1/2) in various cells. The aim of the present study was to examine the effects of PEc on the mobilization and differentiation of hMSCs, as well as the possibility of its implementation in combination with transforming growth factor β1 (TGF-β1) for cartilage repair. The effects of the exogenous administration of PEc and TGF-β1, alone and in combination, on hMSCs were assessed using a trypan blue assay, reverse transcription-quantitative polymerase chain reaction, western blot analysis, Alcian blue staining, wound healing assays and migration/invasion assays. It was determined that PEc is involved in the differentiation process of hMSCs towards hyaline cartilage. Treatment of hMSCs with either PEc, TGF-β1 or both, demonstrated comparable cartilage matrix deposition. Furthermore, treatment with PEc in combination with TGF-β1 was associated with a significant increase in hMSC mobilization when compared with treatment with TGF-β1 or PEc alone (P<0.05). Thus, PEc appears to facilitate in vitro hMSC mobilization and differentiation towards chondrocytes, enhancing the role of TGF-β1. PMID:27571686

  20. Possible role of the Ec peptide of IGF‑1Ec in cartilage repair.

    PubMed

    Armakolas, Nikolaos; Dimakakos, Andreas; Armakolas, Athanasios; Antonopoulos, Athanasios; Koutsilieris, Michael

    2016-10-01

    The Ec peptide (PEc) of insulin-like growth factor 1 Ec (IGF-1Ec) induces human mesenchymal stem cell (hMSC) mobilization and activates extracellular signal‑regulated kinase 1/2 (ERK 1/2) in various cells. The aim of the present study was to examine the effects of PEc on the mobilization and differentiation of hMSCs, as well as the possibility of its implementation in combination with transforming growth factor β1 (TGF‑β1) for cartilage repair. The effects of the exogenous administration of PEc and TGF‑β1, alone and in combination, on hMSCs were assessed using a trypan blue assay, reverse transcription-quantitative polymerase chain reaction, western blot analysis, Alcian blue staining, wound healing assays and migration/invasion assays. It was determined that PEc is involved in the differentiation process of hMSCs towards hyaline cartilage. Treatment of hMSCs with either PEc, TGF‑β1 or both, demonstrated comparable cartilage matrix deposition. Furthermore, treatment with PEc in combination with TGF‑β1 was associated with a significant increase in hMSC mobilization when compared with treatment with TGF‑β1 or PEc alone (P<0.05). Thus, PEc appears to facilitate in vitro hMSC mobilization and differentiation towards chondrocytes, enhancing the role of TGF‑β1. PMID:27571686

  1. Repair of meniscal cartilage white zone tears using a stem cell/collagen-scaffold implant.

    PubMed

    Pabbruwe, Moreica B; Kafienah, Wael; Tarlton, John F; Mistry, Sanjay; Fox, Dennis J; Hollander, Anthony P

    2010-03-01

    Injuries to the avascular region of knee meniscal cartilage do not heal spontaneously. To address this problem we have developed a new stem cell/collagen-scaffold implant system in which human adult bone marrow mesenchymal stem cells are seeded onto a biodegradable scaffold that allows controlled delivery of actively dividing cells to the meniscus surface. Sandwich constructs of two white zone ovine meniscus discs with stem cell/collagen-scaffold implant in between were cultured in vitro for 40 days. Histomorphometric analysis revealed superior integration in the stem cell/collagen-scaffold groups compared to the cell-free collagen membrane or untreated controls. The addition of TGF-beta1 to differentiate stem cells to chondrocytes inhibited integration. Biomechanical testing demonstrated a significant 2-fold increase in tensile strength in all constructs using the stem cell/collagen-scaffold compared to control groups after 40 days in culture. Integration was significantly higher when collagen membranes were used that had a more open/spongy structure adjacent to both meniscal cartilage surfaces, whereas a collagen scaffold designed for osteoinduction failed to induce any integration of meniscus. In conclusion, the stem cell/collagen-scaffold implant is a potential therapeutic treatment for the repair of white zone meniscal cartilage tears.

  2. Programmed Application of Transforming Growth Factor β3 and Rac1 Inhibitor NSC23766 Committed Hyaline Cartilage Differentiation of Adipose-Derived Stem Cells for Osteochondral Defect Repair

    PubMed Central

    Zhu, Shouan; Chen, Pengfei; Wu, Yan; Xiong, Si; Sun, Heng; Xia, Qingqing; Shi, Libing

    2014-01-01

    Hyaline cartilage differentiation is always the challenge with application of stem cells for joint repair. Transforming growth factors (TGFs) and bone morphogenetic proteins can initiate cartilage differentiation but often lead to hypertrophy and calcification, related to abnormal Rac1 activity. In this study, we developed a strategy of programmed application of TGFβ3 and Rac1 inhibitor NSC23766 to commit the hyaline cartilage differentiation of adipose-derived stem cells (ADSCs) for joint cartilage repair. ADSCs were isolated and cultured in a micromass and pellet culture model to evaluate chondrogenic and hypertrophic differentiation. The function of Rac1 was investigated with constitutively active Rac1 mutant and dominant negative Rac1 mutant. The efficacy of ADSCs with programmed application of TGFβ3 and Rac1 inhibitor for cartilage repair was studied in a rat model of osteochondral defects. The results showed that TGFβ3 promoted ADSCs chondro-lineage differentiation and that NSC23766 prevented ADSC-derived chondrocytes from hypertrophy in vitro. The combination of ADSCs, TGFβ3, and NSC23766 promoted quality osteochondral defect repair in rats with much less chondrocytes hypertrophy and significantly higher International Cartilage Repair Society macroscopic and microscopic scores. The findings have illustrated that programmed application of TGFβ3 and Rac1 inhibitor NSC23766 can commit ADSCs to chondro-lineage differentiation and improve the efficacy of ADSCs for cartilage defect repair. These findings suggest a promising stem cell-based strategy for articular cartilage repair. PMID:25154784

  3. Programmed Application of Transforming Growth Factor β3 and Rac1 Inhibitor NSC23766 Committed Hyaline Cartilage Differentiation of Adipose-Derived Stem Cells for Osteochondral Defect Repair.

    PubMed

    Zhu, Shouan; Chen, Pengfei; Wu, Yan; Xiong, Si; Sun, Heng; Xia, Qingqing; Shi, Libing; Liu, Huanhuan; Ouyang, Hong Wei

    2014-10-01

    Hyaline cartilage differentiation is always the challenge with application of stem cells for joint repair. Transforming growth factors (TGFs) and bone morphogenetic proteins can initiate cartilage differentiation but often lead to hypertrophy and calcification, related to abnormal Rac1 activity. In this study, we developed a strategy of programmed application of TGFβ3 and Rac1 inhibitor NSC23766 to commit the hyaline cartilage differentiation of adipose-derived stem cells (ADSCs) for joint cartilage repair. ADSCs were isolated and cultured in a micromass and pellet culture model to evaluate chondrogenic and hypertrophic differentiation. The function of Rac1 was investigated with constitutively active Rac1 mutant and dominant negative Rac1 mutant. The efficacy of ADSCs with programmed application of TGFβ3 and Rac1 inhibitor for cartilage repair was studied in a rat model of osteochondral defects. The results showed that TGFβ3 promoted ADSCs chondro-lineage differentiation and that NSC23766 prevented ADSC-derived chondrocytes from hypertrophy in vitro. The combination of ADSCs, TGFβ3, and NSC23766 promoted quality osteochondral defect repair in rats with much less chondrocytes hypertrophy and significantly higher International Cartilage Repair Society macroscopic and microscopic scores. The findings have illustrated that programmed application of TGFβ3 and Rac1 inhibitor NSC23766 can commit ADSCs to chondro-lineage differentiation and improve the efficacy of ADSCs for cartilage defect repair. These findings suggest a promising stem cell-based strategy for articular cartilage repair.

  4. Intra-articular injection of synovial mesenchymal stem cells improves cartilage repair in a mouse injury model.

    PubMed

    Mak, J; Jablonski, C L; Leonard, C A; Dunn, J F; Raharjo, E; Matyas, J R; Biernaskie, J; Krawetz, R J

    2016-01-01

    Controversy remains whether articular cartilage has an endogenous stem/progenitor cell population, since its poor healing capacity after injury can lead to diseases such as osteoarthritis. In the joint environment there are mesenchymal stem/progenitor cells (MSCs) in the synovial membrane and synovial fluid that can differentiate into cartilage, but it is still under debate if these cells contribute to cartilage repair in vivo. In this study, we isolated a Sca-1 positive, chondrogenesis capable population of mouse synovial MSCs from C57BL6 and MRL/MpJ "super-healer" strains. Intra-articular injection of Sca-1 + GFP + synovial cells from C57BL6 or MRL/MpJ into C57BL6 mice following cartilage injury led to increased cartilage repair by 4 weeks after injury. GFP expression was detected in the injury site at 2 weeks, but not 4 weeks after injury. These results suggest that synovial stem/progenitor cells, regardless of strain background, have beneficial effects when injected into an injured joint. MSCs derived from MRL/MpJ mice did not promote an increased repair capacity compared to MSCs derived from non-healing C57BL6 controls; however, MRL/MpJ MSCs were observed within the defect area at the time points examined, while C57BL6 MSCs were not. PMID:26983696

  5. Cartilage repair by human umbilical cord blood-derived mesenchymal stem cells with different hydrogels in a rat model.

    PubMed

    Park, Yong-Beom; Song, Minjung; Lee, Choong-Hee; Kim, Jin-A; Ha, Chul-Won

    2015-11-01

    This study was carried out to assess the feasibility of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) in articular cartilage repair and to further determine a suitable delivering hydrogel in a rat model. Critical sized full thickness cartilage defects were created. The hUCB-MSCs and three different hydrogel composites (hydrogel A; 4% hyaluronic acid/30% pluronic (1:1, v/v), hydrogel B; 4% hyaluronic acid, and hydrogel C; 4% hyaluronic acid/30% pluronic/chitosan (1:1:2, v/v)) were implanted into the experimental knee (right knee) and hydrogels without hUCB-MSCs were implanted into the control knee (left knee). Defects were evaluated after 8 weeks. The hUCB-MSCs with hydrogels composites resulted in a better repair as seen by gross and histological evaluation compared with hydrogels without hUCB-MSCs. Among the three different hydrogels, the 4% hyaluronic acid hydrogel composite (hydrogel B) showed the best result in cartilage repair as seen by the histological evaluation compared with the other hydrogel composites (hydrogel A and C). The results of this study suggest that hUCB-MSCs may be a promising cell source in combination with 4% hyaluronic acid hydrogels in the in vivo repair of cartilage defects.

  6. Inhibition of Wnt/β-catenin pathway promotes regenerative repair of cutaneous and cartilage injury.

    PubMed

    Bastakoty, Dikshya; Saraswati, Sarika; Cates, Justin; Lee, Ethan; Nanney, Lillian B; Young, Pampee P

    2015-12-01

    Wound healing in mammals is a fibrotic process. The mechanisms driving fibrotic (as opposed to regenerative) repair are poorly understood. Herein we report that therapeutic Wnt inhibition with topical application of small-molecule Wnt inhibitors can reduce fibrosis and promote regenerative cutaneous wound repair. In the naturally stented model of ear punch injury, we found that Wnt/β-catenin pathway is activated most notably in the dermis of the wound bed early (d 2) after injury and subsides to baseline levels by d10. Topical application of either of 2 mechanistically distinct small-molecule Wnt pathway inhibitors (a tankyrase inhibitor, XAV-939, and the U.S. Food and Drug Administration-approved casein kinase activator, pyrvinium) in C57Bl/6J mice resulted in significantly increased rates of wound closure (72.3 ± 14.7% with XAV-939; and 52.1 ± 20.9% with pyrvinium) compared with contralateral controls (38.1 ± 23.0 and 40.4.± 16.7%, respectively). Histologically, Wnt inhibition reduced fibrosis as measured by α-smooth muscle actin positive myofibroblasts and collagen type I α1 synthesis. Wnt inhibition also restored skin architecture including adnexal structures in ear wounds and dermal-epidermal junction with rete pegs in excisional wounds. Additionally, in ear punch injury Wnt inhibitor treatment enabled regeneration of auricular cartilage. Our study shows that pharmacologic Wnt inhibition holds therapeutic utility for regenerative repair of cutaneous wounds. PMID:26268926

  7. Use of bone morphogenetic proteins in mesenchymal stem cell stimulation of cartilage and bone repair

    PubMed Central

    Scarfì, Sonia

    2016-01-01

    The extracellular matrix-associated bone morphogenetic proteins (BMPs) govern a plethora of biological processes. The BMPs are members of the transforming growth factor-β protein superfamily, and they actively participate to kidney development, digit and limb formation, angiogenesis, tissue fibrosis and tumor development. Since their discovery, they have attracted attention for their fascinating perspectives in the regenerative medicine and tissue engineering fields. BMPs have been employed in many preclinical and clinical studies exploring their chondrogenic or osteoinductive potential in several animal model defects and in human diseases. During years of research in particular two BMPs, BMP2 and BMP7 have gained the podium for their use in the treatment of various cartilage and bone defects. In particular they have been recently approved for employment in non-union fractures as adjunct therapies. On the other hand, thanks to their potentialities in biomedical applications, there is a growing interest in studying the biology of mesenchymal stem cell (MSC), the rules underneath their differentiation abilities, and to test their true abilities in tissue engineering. In fact, the specific differentiation of MSCs into targeted cell-type lineages for transplantation is a primary goal of the regenerative medicine. This review provides an overview on the current knowledge of BMP roles and signaling in MSC biology and differentiation capacities. In particular the article focuses on the potential clinical use of BMPs and MSCs concomitantly, in cartilage and bone tissue repair. PMID:26839636

  8. Low friction hydrogel for articular cartilage repair: evaluation of mechanical and tribological properties in comparison with natural cartilage tissue.

    PubMed

    Blum, Michelle M; Ovaert, Timothy C

    2013-10-01

    The mechanical and tribological properties of a novel biomaterial, a boundary lubricant functionalized hydrogel, were investigated and compared to natural cartilage tissue. This low friction hydrogel material was developed for use as a synthetic replacement for focal defects in articular cartilage. The hydrogel was made by functionalizing the biocompatible polymer polyvinyl alcohol with a carboxylic acid derivative boundary lubricant molecule. Two different gel processing techniques were used to create the hydrogels. The first method consisted of initially functionalizing the boundary lubricant to the polyvinyl alcohol and then creating hydrogels by physically crosslinking the reacted polymer. The second method consisted of creating non-functionalized polyvinyl alcohol hydrogels and then performing the functionalization reaction on the fully formed gel. Osteochondral bovine samples were collected and replicate experiments were conducted to compare the mechanical and tribological performance of the boundary lubricant functionalized hydrogels to non-functionalized hydrogels and native cartilage. Friction experiments displayed a maximum decrease in friction coefficient of 70% for the functionalized hydrogels compared to neat polyvinyl alcohol. Indentation investigated the elastic modulus of the hydrogels, demonstrating that stability of the hydrogel was affected by processing method. Hydrogel performance was within the lower ranges of natural cartilage tested under the exact same conditions, showing the potential of the boundary lubricant functionalized hydrogels to perform as a biomimetic synthetic articular cartilage replacement.

  9. Articular cartilage repair with recombinant human type II collagen/polylactide scaffold in a preliminary porcine study.

    PubMed

    Muhonen, Virpi; Salonius, Eve; Haaparanta, Anne-Marie; Järvinen, Elina; Paatela, Teemu; Meller, Anna; Hannula, Markus; Björkman, Mimmi; Pyhältö, Tuomo; Ellä, Ville; Vasara, Anna; Töyräs, Juha; Kellomäki, Minna; Kiviranta, Ilkka

    2016-05-01

    The purpose of this study was to investigate the potential of a novel recombinant human type II collagen/polylactide scaffold (rhCo-PLA) in the repair of full-thickness cartilage lesions with autologous chondrocyte implantation technique (ACI). The forming repair tissue was compared to spontaneous healing (spontaneous) and repair with a commercial porcine type I/III collagen membrane (pCo). Domestic pigs (4-month-old, n = 20) were randomized into three study groups and a circular full-thickness chondral lesion with a diameter of 8 mm was created in the right medial femoral condyle. After 3 weeks, the chondral lesions were repaired with either rhCo-PLA or pCo together with autologous chondrocytes, or the lesion was only debrided and left untreated for spontaneous repair. The repair tissue was evaluated 4 months after the second operation. Hyaline cartilage formed most frequently in the rhCo-PLA treatment group. Biomechanically, there was a trend that both treatment groups resulted in better repair tissue than spontaneous healing. Adverse subchondral bone reactions developed less frequently in the spontaneous group (40%) and the rhCo-PLA treated group (50%) than in the pCo control group (100%). However, no statistically significant differences were found between the groups. The novel rhCo-PLA biomaterial showed promising results in this proof-of-concept study, but further studies will be needed in order to determine its effectiveness in articular cartilage repair. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:745-753, 2016. PMID:26573959

  10. Translation of science to surgery: linking emerging concepts in biological cartilage repair to surgical intervention.

    PubMed

    Moran, C J; Shannon, F J; Barry, F P; O'Byrne, J M; O'Brien, T; Curtin, W

    2010-09-01

    Orthopaedic surgery is in an exciting transitional period as modern surgical interventions, implants and scientific developments are providing new therapeutic options. As advances in basic science and technology improve our understanding of the pathology and repair of musculoskeletal tissue, traditional operations may be replaced by newer, less invasive procedures which are more appropriately targeted at the underlying pathophysiology. However, evidence-based practice will remain a basic requirement of care. Orthopaedic surgeons can and should remain at the forefront of the development of novel therapeutic interventions and their application. Progression of the potential of bench research into an improved array of orthopaedic treatments in an effective yet safe manner will require the development of a subgroup of specialists with extended training in research to play an important role in bridging the gap between laboratory science and clinical practice. International regulations regarding the introduction of new biological treatments will place an additional burden on the mechanisms of this translational process, and orthopaedic surgeons who are trained in science, surgery and the regulatory environment will be essential. Training and supporting individuals with these skills requires special consideration and discussion by the orthopaedic community. In this paper we review some traditional approaches to the integration of orthopaedic science and surgery, the therapeutic potential of current regenerative biomedical science for cartilage repair and ways in which we may develop surgeons with the skills required to translate scientific discovery into effective and properly assessed orthopaedic treatments.

  11. Computational analysis of cartilage implants based on an interpenetrated polymer network for tissue repairing.

    PubMed

    Manzano, Sara; Poveda-Reyes, Sara; Ferrer, Gloria Gallego; Ochoa, Ignacio; Hamdy Doweidar, Mohamed

    2014-10-01

    Interpenetrated polymer networks (IPNs), composed by two independent polymeric networks that spatially interpenetrate, are considered as valuable systems to control permeability and mechanical properties of hydrogels for biomedical applications. Specifically, poly(ethyl acrylate) (PEA)-poly(2-hydroxyethyl acrylate) (PHEA) IPNs have been explored as good hydrogels for mimicking articular cartilage. These lattices are proposed as matrix implants in cartilage damaged areas to avoid the discontinuity in flow uptake preventing its deterioration. The permeability of these implants is a key parameter that influences their success, by affecting oxygen and nutrient transport and removing cellular waste products to healthy cartilage. Experimental try-and-error approaches are mostly used to optimize the composition of such structures. However, computational simulation may offer a more exhaustive tool to test and screen out biomaterials mimicking cartilage, avoiding expensive and time-consuming experimental tests. An accurate and efficient prediction of material's permeability and internal directionality and magnitude of the fluid flow could be highly useful when optimizing biomaterials design processes. Here we present a 3D computational model based on Sussman-Bathe hyperelastic material behaviour. A fluid structure analysis is performed with ADINA software, considering these materials as two phases composites where the solid part is saturated by the fluid. The model is able to simulate the behaviour of three non-biodegradable hydrogel compositions, where percentages of PEA and PHEA are varied. Specifically, the aim of this study is (i) to verify the validity of the Sussman-Bathe material model to simulate the response of the PEA-PHEA biomaterials; (ii) to predict the fluid flux and the permeability of the proposed IPN hydrogels and (iii) to study the material domains where the passage of nutrients and cellular waste products is reduced leading to an inadequate flux

  12. Peripheral Blood Mononuclear Cells Enhance Cartilage Repair in in vivo Osteochondral Defect Model

    PubMed Central

    Hopper, Niina; Wardale, John; Brooks, Roger; Power, Jonathan; Rushton, Neil; Henson, Frances

    2015-01-01

    This study characterized peripheral blood mononuclear cells (PBMC) in terms of their potential in cartilage repair and investigated their ability to improve the healing in a pre-clinical large animal model. Human PBMCs were isolated with gradient centrifugation and adherent PBMC’s were evaluated for their ability to differentiate into adipogenic, chondrogenic and osteogenic lineages and also for their expression of musculoskeletal genes. The phenotype of the PBMCs was evaluated using Stro-1, CD34, CD44, CD45, CD90, CD106, CD105, CD146 and CD166 cell surface markers. Osteochondral defects were created in the medial femoral condyle (MFC) of 24 Welsh mountain sheep and evaluated at a six month time point. Four cell treatment groups were evaluated in combination with collagen-GAG-scaffold: (1) MSC alone; (2) MSCs and PBMCs at a ratio of 20:1; (3) MSCs and PBMC at a ratio of 2:1 and (4) PBMCs alone. Samples from the surgical site were evaluated for mechanical properties, ICRS score and histological repair. Fresh PBMC samples were 90% positive for hematopoietic cell surface markers and negative for the MSC antibody panel (<1%, p = 0.006). However, the adherent PBMC population expressed mesenchymal stem cell markers in hypoxic culture and lacked CD34/45 positive cells (<0.2%). This finding demonstrated that the adherent cells had acquired an MSC-like phenotype and transformed in hypoxia from their original hematopoietic lineage. Four key genes in muskuloskeletal biology were significantly upregulated in adherent PBMCs by hypoxia: BMP2 4.2-fold (p = 0.0007), BMP6 10.7-fold (p = 0.0004), GDF5 2.0-fold (p = 0.002) and COL1 5.0-fold (p = 0.046). The monolayer multilineage analysis confirmed the trilineage mesenchymal potential of the adherent PBMCs. PBMC cell therapy was equally good as bone marrow MSC therapy for defects in the ovine large animal model. Our results show that PBMCs support cartilage healing and oxygen tension of the environment was found to have a key

  13. Comparison of ultrasound and optical coherence tomography techniques for evaluation of integrity of spontaneously repaired horse cartilage.

    PubMed

    Virén, T; Huang, Y P; Saarakkala, S; Pulkkinen, H; Tiitu, V; Linjama, A; Kiviranta, I; Lammi, M J; Brünott, A; Brommer, H; Van Weeren, R; Brama, P A J; Zheng, Y P; Jurvelin, J S; Töyräs, J

    2012-04-01

    The aim of this study was to compare sensitivity of ultrasound and optical coherence tomography (OCT) techniques for the evaluation of the integrity of spontaneously repaired horse cartilage. Articular surfaces of horse intercarpal joints, featuring both intact tissue and spontaneously healed chondral or osteochondral defects, were imaged ex vivo with arthroscopic ultrasound and laboratory OCT devices. Quantitative ultrasound (integrated reflection coefficient (IRC), apparent integrated backscattering coefficient (AIB) and ultrasound roughness index (URI)) and optical parameters (optical reflection coefficient (ORC), optical roughness index (ORI) and optical backscattering (OBS)) were determined and compared with histological integrity and mechanical properties of the tissue. Spontaneously healed tissue could be quantitatively discerned from the intact tissue with ultrasound and OCT techniques. Furthermore, several significant correlations (p < 0.05) were detected between ultrasound and OCT parameters. Superior resolution of OCT provided a more accurate measurement of cartilage surface roughness, while the ultrasound backscattering from the inner structures of the cartilage matched better with the histological findings. Since the techniques were found to be complementary to each other, dual modality imaging techniques could provide a useful tool for the arthroscopic evaluation of the integrity of articular cartilage.

  14. Cartilage Repair and Subchondral Bone Migration Using 3D Printing Osteochondral Composites: A One-Year-Period Study in Rabbit Trochlea

    PubMed Central

    Li, Dichen; Wang, Kunzheng; Hao, Dingjun; Bian, Weiguo; He, Jiankang; Jin, Zhongmin

    2014-01-01

    Increasing evidences show that subchondral bone may play a significant role in the repair or progression of cartilage damage in situ. However, the exact change of subchondral bone during osteochondral repair is still poorly understood. In this paper, biphasic osteochondral composite scaffolds were fabricated by 3D printing technology using PEG hydrogel and β-TCP ceramic and then implanted in rabbit trochlea within a critical size defect model. Animals were euthanized at 1, 2, 4, 8, 16, 24, and 52 weeks after implantation. Histological results showed that hyaline-like cartilage formed along with white smooth surface and invisible margin at 24 weeks postoperatively, typical tidemark formation at 52 weeks. The repaired subchondral bone formed from 16 to 52 weeks in a “flow like” manner from surrounding bone to the defect center gradually. Statistical analysis illustrated that both subchondral bone volume and migration area percentage were highly correlated with the gross appearance Wayne score of repaired cartilage. Therefore, subchondral bone migration is related to cartilage repair for critical size osteochondral defects. Furthermore, the subchondral bone remodeling proceeds in a “flow like” manner and repaired cartilage with tidemark implies that the biphasic PEG/β-TCP composites fabricated by 3D printing provides a feasible strategy for osteochondral tissue engineering application. PMID:25177697

  15. Cartilage repair and subchondral bone migration using 3D printing osteochondral composites: a one-year-period study in rabbit trochlea.

    PubMed

    Zhang, Weijie; Lian, Qin; Li, Dichen; Wang, Kunzheng; Hao, Dingjun; Bian, Weiguo; He, Jiankang; Jin, Zhongmin

    2014-01-01

    Increasing evidences show that subchondral bone may play a significant role in the repair or progression of cartilage damage in situ. However, the exact change of subchondral bone during osteochondral repair is still poorly understood. In this paper, biphasic osteochondral composite scaffolds were fabricated by 3D printing technology using PEG hydrogel and β-TCP ceramic and then implanted in rabbit trochlea within a critical size defect model. Animals were euthanized at 1, 2, 4, 8, 16, 24, and 52 weeks after implantation. Histological results showed that hyaline-like cartilage formed along with white smooth surface and invisible margin at 24 weeks postoperatively, typical tidemark formation at 52 weeks. The repaired subchondral bone formed from 16 to 52 weeks in a "flow like" manner from surrounding bone to the defect center gradually. Statistical analysis illustrated that both subchondral bone volume and migration area percentage were highly correlated with the gross appearance Wayne score of repaired cartilage. Therefore, subchondral bone migration is related to cartilage repair for critical size osteochondral defects. Furthermore, the subchondral bone remodeling proceeds in a "flow like" manner and repaired cartilage with tidemark implies that the biphasic PEG/β-TCP composites fabricated by 3D printing provides a feasible strategy for osteochondral tissue engineering application. PMID:25177697

  16. Cartilage repair and subchondral bone migration using 3D printing osteochondral composites: a one-year-period study in rabbit trochlea.

    PubMed

    Zhang, Weijie; Lian, Qin; Li, Dichen; Wang, Kunzheng; Hao, Dingjun; Bian, Weiguo; He, Jiankang; Jin, Zhongmin

    2014-01-01

    Increasing evidences show that subchondral bone may play a significant role in the repair or progression of cartilage damage in situ. However, the exact change of subchondral bone during osteochondral repair is still poorly understood. In this paper, biphasic osteochondral composite scaffolds were fabricated by 3D printing technology using PEG hydrogel and β-TCP ceramic and then implanted in rabbit trochlea within a critical size defect model. Animals were euthanized at 1, 2, 4, 8, 16, 24, and 52 weeks after implantation. Histological results showed that hyaline-like cartilage formed along with white smooth surface and invisible margin at 24 weeks postoperatively, typical tidemark formation at 52 weeks. The repaired subchondral bone formed from 16 to 52 weeks in a "flow like" manner from surrounding bone to the defect center gradually. Statistical analysis illustrated that both subchondral bone volume and migration area percentage were highly correlated with the gross appearance Wayne score of repaired cartilage. Therefore, subchondral bone migration is related to cartilage repair for critical size osteochondral defects. Furthermore, the subchondral bone remodeling proceeds in a "flow like" manner and repaired cartilage with tidemark implies that the biphasic PEG/β-TCP composites fabricated by 3D printing provides a feasible strategy for osteochondral tissue engineering application.

  17. Effect of Treadmill Exercise Timing on Repair of Full-Thickness Defects of Articular Cartilage by Bone-Derived Mesenchymal Stem Cells: An Experimental Investigation in Rats

    PubMed Central

    Li, Xue; Xu, Chang-peng; Cui, Zhuang; Jiang, Nan; Jia, Jun-jie; Yu, Bin

    2014-01-01

    Objective Current medical practice for the treatment of articular cartilage lesions remains a clinical challenge due to the limited self-repair ability of articular cartilage. Both experimental and clinical researches show that moderate exercise can improve articular cartilage repair process. However, optimal timing of moderate exercise is unclear. We aimed to evaluate the effect of timing of moderate treadmill exercise on repair of full-thickness defects of articular cartilage. Design Full-thickness cartilage defects were drilled in the patellar groove of bilateral femoral condyles in a total of 40 male SD rats before they were randomly assigned into four even groups. In sedentary control (SED) group, no exercise was given; in 2-week (2W), 4-week (4W) and 8-week groups, moderate treadmill exercise was initiated respectively two, four and eight weeks after operation. Half of the animals were sacrificed at week 10 after operation and half at week 14 after operation. Femoral condyles were harvested for gross observation and histochemical measurement by O'Driscoll scoring system. Collagen type II was detected by immunohistochemistry and mRNA expressions of aggrecan and collagen type II cartilage by RT-PCR. Results Both 10 and 14 weeks post-operation, the best results were observed in 4W group and the worst results appeared in 2W group. The histochemistry scores and the expressions of collagen type II and aggrecan were significantly higher in 4W group than that in other three groups (P<0.05). Conclusions Moderate exercise at a selected timing (approximately 4 weeks) after injury can significantly promote the healing of cartilage defects but may hamper the repair process if performed too early while delayed intervention by moderate exercise may reduce its benefits in repair of the defects. PMID:24595327

  18. Repair of Cartilage Defects in Arthritic Tissue with Differentiated Human Embryonic Stem Cells

    PubMed Central

    Olee, Tsaiwei; Grogan, Shawn P.; Lotz, Martin K.; Colwell, Clifford W.

    2014-01-01

    Chondrocytes have been generated in vitro from a range of progenitor cell types and by a number of strategies. However, achieving reconstitution of actual physiologically relevant, appropriately-laminated cartilage in situ that would be applicable to conditions, such as arthritis and cartilage degeneration remains elusive. This lack of success is multifactorial and includes limited cell source, decreased proliferation rate of mature chondrocytes, lack of maintenance of phenotype, reduced matrix synthesis, and poor integration with host tissue. We report an efficient approach for deriving mesenchymal chondroprogenitor cells from human embryonic stem cells. These cells generated tissue containing cartilage-specific matrix proteins that integrated in situ in a partial-thickness defect in ex vivo articular cartilage harvested from human arthritic joints. Given that stem cells provide a virtually inexhaustible supply of starting material and that our technique is easily scalable, cartilaginous tissue primed and grafted in this manner could be suitable for clinical translation. PMID:24028447

  19. The Effect of Exercise on the Early Stages of Mesenchymal Stromal Cell-Induced Cartilage Repair in a Rat Osteochondral Defect Model

    PubMed Central

    Yamaguchi, Shoki; Aoyama, Tomoki; Ito, Akira; Nagai, Momoko; Iijima, Hirotaka; Tajino, Junichi; Zhang, Xiangkai; Kiyan, Wataru; Kuroki, Hiroshi

    2016-01-01

    The repair of articular cartilage is challenging owing to the restriction in the ability of articular cartilage to repair itself. Therefore, cell supplementation therapy is possible cartilage repair method. However, few studies have verified the efficacy and safety of cell supplementation therapy. The current study assessed the effect of exercise on early the phase of cartilage repair following cell supplementation utilizing mesenchymal stromal cell (MSC) intra-articular injection. An osteochondral defect was created on the femoral grooves bilaterally of Wistar rats. Mesenchymal stromal cells that were obtained from male Wistar rats were cultured in monolayer. After 4 weeks, MSCs were injected into the right knee joint and the rats were randomized into an exercise or no-exercise intervention group. The femurs were divided as follows: C group (no exercise without MSC injection); E group (exercise without MSC injection); M group (no exercise with MSC injection); and ME group (exercise with MSC injection). At 2, 4, and 8 weeks after the injection, the femurs were sectioned and histologically graded using the Wakitani cartilage repair scoring system. At 2 weeks after the injection, the total histological scores of the M and ME groups improved significantly compared with those of the C group. Four weeks after the injection, the scores of both the M and ME groups improved significantly. Additionally, the scores in the ME group showed a significant improvement compared to those in the M group. The improvement in the scores of the E, M, and ME groups at 8 weeks were not significantly different. The findings indicate that exercise may enhance cartilage repair after an MSC intra-articular injection. This study highlights the importance of exercise following cell transplantation therapy. PMID:26968036

  20. Sodium Magnetic Resonance Imaging of Ankle Joint in Cadaver Specimens, Volunteers, and Patients After Different Cartilage Repair Techniques at 7 T

    PubMed Central

    Zbýň, Štefan; Brix, Martin O.; Juras, Vladimir; Domayer, Stephan E.; Walzer, Sonja M.; Mlynarik, Vladimir; Apprich, Sebastian; Buckenmaier, Kai; Windhager, Reinhard; Trattnig, Siegfried

    2015-01-01

    Objectives The goal of cartilage repair techniques such as microfracture (MFX) or matrix-associated autologous chondrocyte transplantation (MACT) is to produce repair tissue (RT) with sufficient glycosaminoglycan (GAG) content. Sodium magnetic resonance imaging (MRI) offers a direct and noninvasive evaluation of the GAG content in native cartilage and RT. In the femoral cartilage, this method was able to distinguish between RTs produced by MFX and MACT having different GAG contents. However, it needs to be clarified whether sodium MRI can be useful for evaluating RT in thin ankle cartilage. Thus, the aims of this 7-T study were (1) to validate our sodium MRI protocol in cadaver ankle samples, (2) to evaluate the sodium corrected signal intensities (cSI) in cartilage of volunteers, (3) and to compare sodium values in RT between patients after MFX and MACT treatment. Materials and Methods Five human cadaver ankle samples as well as ankles of 9 asymptomatic volunteers, 6 MFX patients and 6 MACT patients were measured in this 7-T study. Sodium values from the ankle samples were compared with histochemically evaluated GAG content. In the volunteers, sodium cSI values were calculated in the cartilages of ankle and subtalar joint. In the patients, sodium cSI in RT and reference cartilage were measured, morphological appearance of RT was evaluated using the magnetic resonance observation of cartilage repair tissue (MOCART) scoring system, and clinical outcome before and after surgery was assessed using the American Orthopaedic Foot and Ankle Society score and Modified Cincinnati Knee Scale. All regions of interest were defined on morphological images and subsequently transferred to the corresponding sodium images. Analysis of variance, t tests, and Pearson correlation coefficients were evaluated. Results In the patients, significantly lower sodium cSI values were found in RT than in reference cartilage for the MFX (P = 0.007) and MACT patients (P = 0.008). Sodium cSI and

  1. A Model to Study Articular Cartilage Mechanical and Biological Responses to Sliding Loads.

    PubMed

    Schätti, Oliver R; Gallo, Luigi M; Torzilli, Peter A

    2016-08-01

    In physiological conditions, joint function involves continuously moving contact areas over the tissue surface. Such moving contacts play an important role for the durability of the tissue. It is known that in pathological joints these motion paths and contact mechanics change. Nevertheless, limited information exists on the impact of such physiological and pathophysiological dynamic loads on cartilage mechanics and its subsequent biological response. We designed and validated a mechanical device capable of applying simultaneous compression and sliding forces onto cartilage explants to simulate moving joint contact. Tests with varying axial loads (1-4 kg) and sliding speeds (1-20 mm/s) were performed on mature viable bovine femoral condyles to investigate cartilage mechanobiological responses. High loads and slow sliding speeds resulted in highest cartilage deformations. Contact stress and effective cartilage moduli increased with increasing load and increasing speed. In a pilot study, changes in gene expression of extracellular matrix proteins were correlated with strain, contact stress and dynamic effective modulus. This study describes a mechanical test system to study the cartilage response to reciprocating sliding motion and will be helpful in identifying mechanical and biological mechanisms leading to the initiation and development of cartilage degeneration.

  2. Gene- and stem cell-based therapeutics for cartilage regeneration and repair.

    PubMed

    Tang, Ying; Wang, Bing

    2015-04-15

    Cell-based regeneration of damaged or diseased articular cartilage still faces significant clinical challenge due to inadequate environmental regulation of stem cell proliferation and chondrogenic differentiation. The role of insulin-like growth factor in critical steps of human bone marrow-derived mesenchymal stem cell chondrogenesis has potential in optimizing the therapeutic use of mesenchymal stem cells in cartilage disorders. In addition to the previously described benefits of recombinant adeno-associated viral vector for in vivo gene therapy, demonstrated by Frisch and colleagues, such vector is also a safe and efficient delivery system for the genetic modification of human bone marrow-derived mesenchymal stem cells via ex vivo insulin-like growth factor 1 gene transfer, so that implanted mesenchymal stem cells continuously release a therapeutic level of insulin-like growth factor 1 to achieve sustained mesenchymal stem cell chondrogenesis for cartilage regeneration.

  3. Quantifying the lubricity of mechanically tough polyvinyl alcohol hydrogels for cartilage repair.

    PubMed

    Ling, Doris; Bodugoz-Senturk, Hatice; Nanda, Salil; Braithwaite, Gavin; Muratoglu, Orhun K

    2015-12-01

    Polyvinyl alcohol hydrogels are biocompatible and can be used as synthetic articular cartilage. Their mechanical characteristics can be tailored by various techniques such as annealing or blending with other hydrophilic polymers. In this study, we quantified the coefficient of friction of various candidate polyvinyl alcohol hydrogels against cobalt-chrome alloy or swine cartilage using a new rheometer-based method. We investigated the coefficient of friction of polyvinyl alcohol-only hydrogels and blends with polyethylene glycol, polyacrylic acid, and polyacrylamide against swine cartilage and polished cobalt-chrome surfaces. The addition of the functional groups to polyvinyl alcohol, such as acrylamide (semi-interpenetrating network) and acrylic acid (blend), significantly reduced the coefficient of friction. The coefficient of friction of the polyvinyl alcohol-only hydrogel was measured as 0.4 ± 0.03 against cobalt-chrome alloy, and 0.09 ± 0.004 against cartilage, while those measurements for the polyvinyl alcohol-polyacrylic acid blends and polyvinyl alcohol-polyacrylamide semi-interpenetrating network were 0.07 ± 0.01 and 0.1 ± 0.003 against cobalt-chrome alloy, and 0.03 ± 0.001 and 0.02 ± 0.001 against cartilage, respectively. There was no significant or minimal difference in the coefficient of friction between samples from different regions of the knee, or animals, or when the cartilage samples were frozen for 1 day or 2 days before testing. However, changing lubricant from deionized water to ionic media, for example, saline or simulated body fluid, increased the coefficient of friction significantly.

  4. Extracellular Matrix (ECM) Multilayer Membrane as a Sustained Releasing Growth Factor Delivery System for rhTGF-β3 in Articular Cartilage Repair

    PubMed Central

    Park, Sang-Hyug; Kim, Moon Suk; Kim, Young Jick; Choi, Byung Hyune; Lee, Chun Tek; Park, So Ra; Min, Byoung-Hyun

    2016-01-01

    Recombinant human transforming growth factor beta-3 (rhTGF-β3) is a key regulator of chondrogenesis in stem cells and cartilage formation. We have developed a novel drug delivery system that continuously releases rhTGF-β3 using a multilayered extracellular matrix (ECM) membrane. We hypothesize that the sustained release of rhTGF-β3 could activate stem cells and result in enhanced repair of cartilage defects. The properties and efficacy of the ECM multilayer-based delivery system (EMLDS) are investigated using rhTGF-β3 as a candidate drug. The bioactivity of the released rhTGF-ß3 was evaluated through chondrogenic differentiation of mesenchymal stem cells (MSCs) using western blot and circular dichroism (CD) analyses in vitro. The cartilage reparability was evaluated through implanting EMLDS with endogenous and exogenous MSC in both in vivo and ex vivo models, respectively. In the results, the sustained release of rhTGF-ß3 was clearly observed over a prolonged period of time in vitro and the released rhTGF-β3 maintained its structural stability and biological activity. Successful cartilage repair was also demonstrated when rabbit MSCs were treated with rhTGF-β3-loaded EMLDS ((+) rhTGF-β3 EMLDS) in an in vivo model and when rabbit chondrocytes and MSCs were treated in ex vivo models. Therefore, the multilayer ECM membrane could be a useful drug delivery system for cartilage repair. PMID:27258120

  5. Effects of Hyaluronic Acid and γ–Globulin Concentrations on the Frictional Response of Human Osteoarthritic Articular Cartilage

    PubMed Central

    Son, Kyeong-Min; Thompson, Mark S.; Park, Sungchan; Chang, Jun-Dong; Nam, Ju-Suk; Park, Seonghun; Lee, Sang-Soo

    2014-01-01

    Synovial fluid plays an important role in lubricating synovial joints. Its main constituents are hyaluronic acid (HA) and γ–globulin, acting as boundary lubricants for articular cartilage. The aim of the study was to demonstrate the concentration-dependent effect of HA and γ–globulin on the boundary-lubricating ability of human osteoarthritis (OA) cartilage. Normal, early and advance stage articular cartilage samples were obtained from human femoral heads and in presence of either HA or γ–globulin, cartilage frictional coefficient (µ) was measured by atomic force microscopy (AFM). In advanced stage OA, the cartilage superficial layer was observed to be completely removed and the damaged cartilage surface showed a higher µ value (∼0.409) than the normal cartilage surface (∼0.119) in PBS. Adsorbed HA and γ–globulin molecules significantly improved the frictional behavior of advanced OA cartilage, while they were ineffective for normal and early OA cartilage. In advanced-stage OA, the concentration-dependent frictional response of articular cartilage was observed with γ–globulin, but not with HA. Our result suggested that HA and γ–globulin may play a significant role in improving frictional behavior of advanced OA cartilage. During early-stage OA, though HA and γ–globulin had no effect on improving frictional behavior of cartilage, however, they might contribute to disease modifying effects of synovial fluid as observed in clinical settings. PMID:25426992

  6. A new heterologous fibrin sealant as a scaffold to cartilage repair-Experimental study and preliminary results.

    PubMed

    de Barros, Caio Nunes; Miluzzi Yamada, Ana Lúcia; Junior, Rui Seabra F; Barraviera, Benedito; Hussni, Carlos Alberto; de Souza, Jaqueline Brandão; Watanabe, Marcos Jun; Rodrigues, Celso Antônio; Garcia Alves, Ana Liz

    2016-07-01

    Autologous fibrin gel is commonly used as a scaffold for filling defects in articular cartilage. This biomaterial can also be used as a sealant to control small hemorrhages and is especially helpful in situations where tissue reparation capacity is limited. In particular, fibrin can act as a scaffold for various cell types because it can accommodate cell migration, differentiation, and proliferation. Despite knowledge of the advantages of this biomaterial and mastery of the techniques required for its application, the durability of several types of sealant at the site of injury remains questionable. Due to the importance of such data for evaluating the quality and efficiency of fibrin gel formulations on its use as a scaffold, this study sought to analyze the heterologous fibrin sealant developed from the venom of Crotalus durissus terrificus using studies in ovine experimental models. The fibrin gel developed from the venom of this snake was shown to act as a safe, stable, and durable scaffold for up to seven days, without causing adverse side effects. Fibrin gel produced from the venom of the Crotalus durissus terrificus snake possesses many clinical and surgical uses. It presents the potential to be used as a biomaterial to help repair skin lesions or control bleeding, and it may also be used as a scaffold when applied together with various cell types. The intralesional use of the fibrin gel from the venom of this snake may improve surgical and clinical treatments in addition to being inexpensive and adequately consistent, durable, and stable. The new heterologous fibrin sealant is a scaffold candidate to cartilage repair in this study.

  7. In-situ crosslinkable and self-assembling elastin-like polypeptide block copolymers for cartilage tissue repair

    NASA Astrophysics Data System (ADS)

    Lim, Dong Woo

    This work describes the development of genetically engineered elastin-like polypeptide (ELP) block copolymers as in-situ gelling scaffolds for cartilage tissue repair. The central hypothesis underlying this work is that ELP based biopolymers can be exploited as injectable biomaterials by rapid chemical crosslinking. To prove this, gene libraries encoding ELP having different molecular weights and amino acid sequences, and ELP block copolymers composed of various ELP blocks having diverse amino acid composition, length, and phase transition behavior were synthesized by recursive directional ligation, expressed in E. Coli and purified by inverse transition cycling. Mannich-type condensation of hydroxymethylphosphines (HMPs) with primary- and secondary-amines of amino acids was developed as a new crosslinking method of polypeptides. Chemically crosslinked ELP hydrogels were formed rapidly in an aqueous solution by reaction of ELPs containing periodic lysine residues with HMPs. The crosslinking density and mechanical property of the ELP hydrogels were controlled at the sequence level by varying the Lys density in ELPs composed of mono-block as well as by segregation of the Lys residues within specific blocks of tri-block architectures. Fibroblasts embedded in ELP hydrogels survived the crosslinking process and were viable after in vitro culture for at least 3 days. The DNA content of fibroblasts within the tri-block gels was significantly higher than that in the mono-block gels at day 3. These results suggest that the HMP crosslinked ELP block copolymer hydrogels show finely tuned mechanical properties and different microenvironments for cell viability as well as potential as in-situ crosslinkable biopolymers for tissue repair applications with load-bearing environments. As an alternative, rheological behavior of the ELP block copolymers and ELP-grafted hyaluronic acids (HAs) as artificial extracellular matrices (ECMs) showed that they were thermally aggregated into

  8. Proteomic Analysis Profile of Engineered Articular Cartilage with Chondrogenic Differentiated Adipose Tissue-Derived Stem Cells Loaded Polyglycolic Acid Mesh for Weight-Bearing Area Defect Repair

    PubMed Central

    Gong, Lunli; Zhou, Xiao; Wu, Yaohao; Zhang, Yun; Wang, Chen; Zhou, Heng; Guo, Fangfang

    2014-01-01

    The present study was designed to investigate the possibility of full-thickness defects repair in porcine articular cartilage (AC) weight-bearing area using chondrogenic differentiated autologous adipose-derived stem cells (ASCs) with a follow-up of 3 and 6 months, which is successive to our previous study on nonweight-bearing area. The isolated ASCs were seeded onto the phosphoglycerate/polylactic acid (PGA/PLA) with chondrogenic induction in vitro for 2 weeks as the experimental group prior to implantation in porcine AC defects (8 mm in diameter, deep to subchondral bone), with PGA/PLA only as control. With follow-up time being 3 and 6 months, both neo-cartilages of postimplantation integrated well with the neighboring normal cartilage and subchondral bone histologically in experimental group, whereas only fibrous tissue in control group. Immunohistochemical and toluidine blue staining confirmed similar distribution of COL II and glycosaminoglycan in the regenerated cartilage to the native one. A vivid remolding process with repair time was also witnessed in the neo-cartilage as the compressive modulus significantly increased from 70% of the normal cartilage at 3 months to nearly 90% at 6 months, which is similar to our former research. Nevertheless, differences of the regenerated cartilages still could be detected from the native one. Meanwhile, the exact mechanism involved in chondrogenic differentiation from ASCs seeded on PGA/PLA is still unknown. Therefore, proteome is resorted leading to 43 proteins differentially identified from 20 chosen two-dimensional spots, which do help us further our research on some committed factors. In conclusion, the comparison via proteome provided a thorough understanding of mechanisms implicating ASC differentiation toward chondrocytes, which is further substantiated by the present study as a perfect supplement to the former one in nonweight-bearing area. PMID:24044689

  9. Marine Collagen Scaffolds for Nasal Cartilage Repair: Prevention of Nasal Septal Perforations in a New Orthotopic Rat Model Using Tissue Engineering Techniques

    PubMed Central

    Bermueller, Christian; Elsaesser, Alexander F.; Sewing, Judith; Baur, Nina; von Bomhard, Achim; Scheithauer, Marc; Notbohm, Holger; Rotter, Nicole

    2013-01-01

    Autologous grafts are frequently needed for nasal septum reconstruction. Because they are only available in limited amounts, there is a need for new cartilage replacement strategies. Tissue engineering based on the use of autologous chondrocytes and resorbable matrices might be a suitable option. So far, an optimal material for nasal septum reconstruction has not been identified. The aim of our study was to provide the first evaluation of marine collagen for use in nasal cartilage repair. First, we studied the suitability of marine collagen as a cartilage replacement matrix in the context of in vitro three dimensional cultures by analyzing cell migration, cytotoxicity, and extracellular matrix formation using human and rat nasal septal chondrocytes. Second, we worked toward developing a suitable orthotopic animal model for nasal septum repair, while simultaneously evaluating the biocompatibility of marine collagen. Seeded and unseeded scaffolds were transplanted into nasal septum defects in an orthotopic rat model for 1, 4, and 12 weeks. Explanted scaffolds were histologically and immunohistochemically evaluated. Scaffolds did not induce any cytotoxic reactions in vitro. Chondrocytes were able to adhere to marine collagen and produce cartilaginous matrix proteins, such as collagen type II. Treating septal cartilage defects in vivo with seeded and unseeded scaffolds led to a significant reduction in the number of nasal septum perforations compared to no replacement. In summary, we demonstrated that marine collagen matrices provide excellent properties for cartilage tissue engineering. Marine collagen scaffolds are able to prevent septal perforations in an autologous, orthotopic rat model. This newly described experimental surgical procedure is a suitable way to evaluate new scaffold materials for their applicability in the context of nasal cartilage repair. PMID:23621795

  10. DNA repair responses in human skin cells

    SciTech Connect

    Hanawalt, P.C.; Liu, S.C.; Parsons, C.S.

    1981-07-01

    Sunlight and some environmental chemical agents produce lesions in the DNA of human skin cells that if unrepaired may interfere with normal functioning of these cells. The most serious outcome of such interactions may be malignancy. It is therefore important to develop an understanding of mechanisms by which the lesions may be repaired or tolerated without deleterious consequences. Our models for the molecular processing of damaged DNA have been derived largely from the study of bacterial systems. Some similarities but significant differences are revealed when human cell responses are tested against these models. It is also of importance to learn DNA repair responses of epidermal keratinocytes for comparison with the more extensive studies that have been carried out with dermal fibroblasts. Our experimental results thus far indicate similarities for the excision-repair of ultraviolet-induced pyrimidine dimers in human keratinocytes and fibroblasts. Both the monoadducts and the interstrand crosslinks produced in DNA by photoactivated 8-methoxypsoralen (PUVA) can be repaired in normal human fibroblasts but not in those from xeroderma pigmentosum patients. The monoadducts, like pyrimidine dimers, are probably the more mutagenic/carcinogenic lesions while the crosslinks are less easily repaired and probably result in more effective blocking of DNA function. It is suggested that a split-dose protocol that maximizes the production of crosslinks while minimizing the yield of monoadducts may be more effective and potentially less carcinogenic than the single ultraviolet exposure regimen in PUVA therapy for psoriasis.

  11. A 5-Year Follow-Up After Cartilage Repair in the Knee Using a Platelet-Rich Plasma-Immersed Polymer-Based Implant

    PubMed Central

    Siclari, Alberto; Mascaro, Gennaro; Kaps, Christian; Boux, Eugenio

    2014-01-01

    The aim of our study was to analyze the clinical outcome after repair of cartilage defects of the knee with subchondral drilling and resorbable polymer-based implants immersed with autologous platelet-rich plasma (PRP). Fifty-two patients with focal chondral defects were treated with subchondral drilling, followed by covering with a polyglycolic acid - hyaluronan (PGA-HA) implant (chondrotissue®) immersed with autologous PRP. At 5-year follow-up, patients’ situation was assessed using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and compared to the pre-operative situation. The KOOS showed clinically meaningful and significant (p < 0.05) improvement in all subcategories compared to baseline. Subgroup analysis showed that there were no differences in the clinical outcome regarding defect size and localization as well as degenerative condition of the knee. Cartilage repair was complete in 20 out of 21 patients at 4-year follow-up as shown by magnetic resonance observation of cartilage repair tissue (MOCART) scoring. Covering of focal cartilage defects with the PGA-HA implant and PRP after bone marrow stimulation leads to a lasting improvement of the patients’ situation. PMID:25352927

  12. Next Generation Mesenchymal Stem Cell (MSC)–Based Cartilage Repair Using Scaffold-Free Tissue Engineered Constructs Generated with Synovial Mesenchymal Stem Cells

    PubMed Central

    Shimomura, Kazunori; Ando, Wataru; Moriguchi, Yu; Sugita, Norihiko; Yasui, Yukihiko; Koizumi, Kota; Fujie, Hiromichi; Hart, David A.; Yoshikawa, Hideki

    2015-01-01

    Because of its limited healing capacity, treatments for articular cartilage injuries are still challenging. Since the first report by Brittberg, autologous chondrocyte implantation has been extensively studied. Recently, as an alternative for chondrocyte-based therapy, mesenchymal stem cell–based therapy has received considerable research attention because of the relative ease in handling for tissue harvest, and subsequent cell expansion and differentiation. This review summarizes latest development of stem cell therapies in cartilage repair with special attention to scaffold-free approaches. PMID:27340513

  13. Use of a biological reactor and platelet-rich plasma for the construction of tissue-engineered bone to repair articular cartilage defects

    PubMed Central

    Li, Huibo; Sun, Shui; Liu, Haili; Chen, Hua; Rong, Xin; Lou, Jigang; Yang, Yunbei; Yang, Yi; Liu, Hao

    2016-01-01

    Articular cartilage defects are a major clinical burden worldwide. Current methods to repair bone defects include bone autografts, allografts and external fixation. In recent years, the repair of bone defects by tissue engineering has emerged as a promising approach. The present study aimed to assess a novel method using a biological reactor with platelet-rich plasma to construct tissue-engineered bone. Beagle bone marrow mesenchymal stem cells (BMSCs) were isolated and differentiated into osteoblasts and chondroblasts using platelet-rich plasma and tricalcium phosphate scaffolds cultured in a bioreactor for 3 weeks. The cell scaffold composites were examined by scanning electron microscopy (SEM) and implanted into beagles with articular cartilage defects. The expression of osteogenic markers, alkaline phosphatase and bone γ-carboxyglutamate protein (BGLAP) were assessed using polymerase chain reaction after 3 months. Articular cartilage specimens were observed histologically. Adhesion and distribution of BMSCs on the β-tricalcium phosphate (β-TCP) scaffold were confirmed by SEM. Histological examination revealed that in vivo bone defects were largely repaired 12 weeks following implantation. The expression levels of alkaline phosphatase (ALP) and BGLAP in the experimental groups were significantly elevated compared with the negative controls. BMSCs may be optimum seed cells for tissue engineering in bone repair. Platelet-rich plasma (PRP) provides a rich source of cytokines to promote BMSC function. The β-TCP scaffold is advantageous for tissue engineering due to its biocompatibility and 3D structure that promotes cell adhesion, growth and differentiation. The tissue-engineered bone was constructed in a bioreactor using BMSCs, β-TCP scaffolds and PRP and displayed appropriate morphology and biological function. The present study provides an efficient method for the generation of tissue-engineered bone for cartilage repair, compared with previously used

  14. An emergency response team for membrane repair

    NASA Technical Reports Server (NTRS)

    McNeil, Paul L.; Kirchhausen, Tom

    2005-01-01

    On demand, rapid Ca(2+)-triggered homotypic and exocytic membrane-fusion events are required to repair a torn plasma membrane, and we propose that this emergency-based fusion differs fundamentally from other rapid, triggered fusion reactions. Emergency fusion might use a specialized protein and organelle emergency response team that can simultaneously promote impromptu homotypic fusion events between organelles and exocytic fusion events along the vertices between these fusion products and the plasma membrane.

  15. Articular Cartilage Injury in Athletes

    PubMed Central

    McAdams, Timothy R.; Mithoefer, Kai; Scopp, Jason M.; Mandelbaum, Bert R.

    2010-01-01

    Articular cartilage lesions in the athletic population are observed with increasing frequency and, due to limited intrinsic healing capacity, can lead to progressive pain and functional limitation over time. If left untreated, isolated cartilage lesions can lead to progressive chondropenia or global cartilage loss over time. A chondropenia curve is described to help predict the outcome of cartilage injury based on different lesion and patient characteristics. Nutriceuticals and chondroprotective agents are being investigated as tools to slow the development of chondropenia. Several operative techniques have been described for articular cartilage repair or replacement and, more recently, cartilage regeneration. Rehabilitation guidelines are being developed to meet the needs of these new techniques. Next-generation techniques are currently evaluated to optimize articular cartilage repair biology and to provide a repair cartilage tissue that can withstand the high mechanical loads experienced by the athlete with consistent long-term durability. PMID:26069548

  16. A bioactive hybrid three-dimensional tissue-engineering construct for cartilage repair.

    PubMed

    Ainola, Mari; Tomaszewski, Waclaw; Ostrowska, Barbara; Wesolowska, Ewa; Wagner, H Daniel; Swieszkowski, Wojciech; Sillat, Tarvo; Peltola, Emilia; Konttinen, Yrjö T

    2016-01-01

    The aim was to develop a hybrid three-dimensional-tissue engineering construct for chondrogenesis. The hypothesis was that they support chondrogenesis. A biodegradable, highly porous polycaprolactone-grate was produced by solid freeform fabrication. The polycaprolactone support was coated with a chitosan/polyethylene oxide nanofibre sheet produced by electrospinning. Transforming growth factor-β3-induced chondrogenesis was followed using the following markers: sex determining region Y/-box 9, runt-related transcription factor 2 and collagen II and X in quantitative real-time polymerase chain reaction, histology and immunostaining. A polycaprolactone-grate and an optimized chitosan/polyethylene oxide nanofibre sheet supported cellular aggregation, chondrogenesis and matrix formation. In tissue engineering constructs, the sheets were seeded first with mesenchymal stem cells and then piled up according to the lasagne principle. The advantages of such a construct are (1) the cells do not need to migrate to the tissue engineering construct and therefore pore size and interconnectivity problems are omitted and (2) the cell-tight nanofibre sheet and collagen-fibre network mimic a cell culture platform for mesenchymal stem cells/chondrocytes (preventing escape) and hinders in-growth of fibroblasts and fibrous scarring (preventing capture). This allows time for the slowly progressing, multiphase true cartilage regeneration.

  17. Steric Interference of Adhesion Supports In-Vitro Chondrogenesis of Mesenchymal Stem Cells on Hydrogels for Cartilage Repair

    PubMed Central

    Goldshmid, Revital; Cohen, Shlomit; Shachaf, Yonatan; Kupershmit, Ilana; Sarig-Nadir, Offra; Seliktar, Dror; Wechsler, Roni

    2015-01-01

    Recent studies suggest the presence of cell adhesion motifs found in structural proteins can inhibit chondrogenesis. In this context, the current study aims to determine if a polyethylene glycol (PEG)-modified fibrinogen matrix could support better chondrogenesis of human bone marrow mesenchymal stem cells (BM-MSC) based on steric interference of adhesion, when compared to a natural fibrin matrix. Hydrogels used as substrates for two-dimensional (2D) BM-MSC cultures under chondrogenic conditions were made from cross-linked PEG-fibrinogen (PF) and compared to thrombin-activated fibrin. Cell morphology, protein expression, DNA and sulfated proteoglycan (GAG) content were correlated to substrate properties such as stiffness and adhesiveness. Cell aggregation and chondrogenic markers, including collagen II and aggrecan, were observed on all PF substrates but not on fibrin. Shielding fibrinogen’s adhesion domains and increasing stiffness of the material are likely contributing factors that cause the BM-MSCs to display a more chondrogenic phenotype. One composition of PF corresponding to GelrinC™—a product cleared in the EU for cartilage repair—was found to be optimal for supporting chondrogenic differentiation of BM-MSC while minimizing hypertrophy (collagen X). These findings suggest that semi-synthetic biomaterials based on ECM proteins can be designed to favourably affect BM-MSC towards repair processes involving chondrogenesis. PMID:26411496

  18. Comparison of international guidelines for regenerative medicine: Knee cartilage repair and replacement using human-derived cells and tissues.

    PubMed

    Itoh, Kuni; Kano, Shingo

    2016-07-01

    Regenerative medicine (RM) is an emerging field using human-derived cells and tissues (HCT). Due to the complexity and diversity of HCT products, each country has its own regulations for authorization and no common method has been applied to date. Individual regulations were previously clarified at the level of statutes but no direct comparison has been reported at the level of guidelines. Here, we generated a new analytical framework that allows comparison of guidelines independent from local definitions of RM, using 2 indicators, product type and information type. The guidelines for products for repair and replacement of knee cartilage in Japan, the United States of America, and Europe were compared and differences were detected in both product type and information type by the proposed analytical framework. Those findings will be critical not only for the product developers to determine the region to initiate the clinical trials but also for the regulators to assess and build their regulations. This analytical framework is potentially expandable to other RM guidelines to identify gaps, leading to trigger discussion of global harmonization in RM regulations. PMID:27156144

  19. Highly nonlinear stress-relaxation response of articular cartilage in indentation: Importance of collagen nonlinearity.

    PubMed

    Mäkelä, J T A; Korhonen, R K

    2016-06-14

    Modern fibril-reinforced computational models of articular cartilage can include inhomogeneous tissue composition and structure, and nonlinear mechanical behavior of collagen, proteoglycans and fluid. These models can capture well experimental single step creep and stress-relaxation tests or measurements under small strains in unconfined and confined compression. Yet, it is known that in indentation, especially at high strain velocities, cartilage can express highly nonlinear response. Different fibril reinforced poroelastic and poroviscoelastic models were used to assess measured highly nonlinear stress-relaxation response of rabbit articular cartilage in indentation. Experimentally measured depth-dependent volume fractions of different tissue constituents and their mechanical nonlinearities were taken into account in the models. In particular, the collagen fibril network was modeled using eight separate models that implemented five different constitutive equations to describe the nonlinearity. These consisted of linear elastic, nonlinear viscoelastic and multiple nonlinear elastic representations. The model incorporating the most nonlinearly increasing Young׳s modulus of collagen fibrils as a function of strain captured best the experimental data. Relative difference between the model and experiment was ~3%. Surprisingly, the difference in the peak forces between the experiment and the model with viscoelastic collagen fibrils was almost 20%. Implementation of the measured volume fractions did not improve the ability of the model to capture the measured mechanical data. These results suggest that a highly nonlinear formulation for collagen fibrils is needed to replicate multi-step stress-relaxation response of rabbit articular cartilage in indentation with high strain rates. PMID:27130474

  20. Highly nonlinear stress-relaxation response of articular cartilage in indentation: Importance of collagen nonlinearity.

    PubMed

    Mäkelä, J T A; Korhonen, R K

    2016-06-14

    Modern fibril-reinforced computational models of articular cartilage can include inhomogeneous tissue composition and structure, and nonlinear mechanical behavior of collagen, proteoglycans and fluid. These models can capture well experimental single step creep and stress-relaxation tests or measurements under small strains in unconfined and confined compression. Yet, it is known that in indentation, especially at high strain velocities, cartilage can express highly nonlinear response. Different fibril reinforced poroelastic and poroviscoelastic models were used to assess measured highly nonlinear stress-relaxation response of rabbit articular cartilage in indentation. Experimentally measured depth-dependent volume fractions of different tissue constituents and their mechanical nonlinearities were taken into account in the models. In particular, the collagen fibril network was modeled using eight separate models that implemented five different constitutive equations to describe the nonlinearity. These consisted of linear elastic, nonlinear viscoelastic and multiple nonlinear elastic representations. The model incorporating the most nonlinearly increasing Young׳s modulus of collagen fibrils as a function of strain captured best the experimental data. Relative difference between the model and experiment was ~3%. Surprisingly, the difference in the peak forces between the experiment and the model with viscoelastic collagen fibrils was almost 20%. Implementation of the measured volume fractions did not improve the ability of the model to capture the measured mechanical data. These results suggest that a highly nonlinear formulation for collagen fibrils is needed to replicate multi-step stress-relaxation response of rabbit articular cartilage in indentation with high strain rates.

  1. BST-CarGel® Treatment Maintains Cartilage Repair Superiority over Microfracture at 5 Years in a Multicenter Randomized Controlled Trial

    PubMed Central

    Stanish, William D.; McCormack, Robert; Forriol, Francisco; Mohtadi, Nicholas; Pelet, Stéphane; Desnoyers, Jacques; Méthot, Stéphane; Vehik, Kendra; Restrepo, Alberto

    2015-01-01

    Objective The efficacy and safety of BST-CarGel®, a chitosan scaffold for cartilage repair was compared with microfracture alone at 1 year during a multicenter randomized controlled trial in the knee. This report was undertaken to investigate 5-year structural and clinical outcomes. Design The international randomized controlled trial enrolled 80 patients, aged 18 to 55 years, with grade III or IV focal lesions on the femoral condyles. Patients were randomized to receive BST-CarGel® treatment or microfracture alone, and followed standardized 12-week rehabilitation. Co-primary endpoints of repair tissue quantity and quality were evaluated by 3-dimensional MRI quantification of the degree of lesion filling (%) and T2 relaxation times. Secondary endpoints were clinical benefit measured with WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) questionnaires and safety. General estimating equations were used for longitudinal statistical analysis of repeated measures. Results Blinded MRI analysis demonstrated that BST-CarGel®-treated patients showed a significantly greater treatment effect for lesion filling (P = 0.017) over 5 years compared with microfracture alone. A significantly greater treatment effect for BST-CarGel® was also found for repair tissue T2 relaxation times (P = 0.026), which were closer to native cartilage compared to the microfracture group. BST-CarGel® and microfracture groups showed highly significant improvement at 5 years from pretreatment baseline for each WOMAC subscale (P < 0.0001), and there were no differences between the treatment groups. Safety was comparable for both groups. Conclusions BST-CarGel® was shown to be an effective mid-term cartilage repair treatment. At 5 years, BST-CarGel® treatment resulted in sustained and significantly superior repair tissue quantity and quality over microfracture alone. Clinical benefit following BST-CarGel® and microfracture treatment were highly significant over baseline

  2. Species variability in the differentiation potential of in vitro-expanded articular chondrocytes restricts predictive studies on cartilage repair using animal models.

    PubMed

    Giannoni, Paolo; Crovace, Antonio; Malpeli, Mara; Maggi, Ettore; Arbicò, Rafaella; Cancedda, Ranieri; Dozin, Beatrice

    2005-01-01

    Autologous chondrocyte implantation is currently applied in clinics as an innovative tool for articular cartilage repair. Animal models have been and still are being used to validate and further improve the technique. However, in various species, the outcome varies from hyaline-like cartilage to fibrocartilage. This may be due partly to the spontaneous dedifferentiation of chondrocytes once cultured in vitro. Here we assessed whether the extent of dedifferentiation varies between species and we hypothesized that the level of chondrocyte phenotype stability during expansion may contribute to the maintenance of their chondrogenic commitment and redifferentiation potential. Condyle chondrocytes were harvested from sheep, dog, and human, and expanded for 1, 6, or 12 cell duplications. At each interval, cell phenotype was monitored (morphology and biosynthesis of cartilage markers) and redifferentiation was assessed by an in vitro assay of chondrogenesis in micromass pellet and an in vivo assay of ectopic cartilage formation in immunodeficient mice. Results indicate that, during culture, the sheep chondrocyte phenotype is maintained better than that of human chondrocytes, which in turn dedifferentiate to a lesser extent than dog chondrocytes Accordingly, after expansion, sheep chondrocytes spontaneously reform hyaline-like cartilage; human chondrocytes redifferentiate only under stimulation with chondrogenic inducers whereas, after a few passages, dog chondrocytes lose any capacity to redifferentiate regardless of the presence of inducers. Thus, conditions allowing cartilage formation in one species are not necessarily transposable to other species. Therefore, results with animal models should be cautiously applied to humans. In addition, for tissue-engineering purposes, the number of cell duplications must be, for each species, carefully monitored to remain in the range of amplification allowing redifferentiation and chondrogenesis.

  3. Role of Chondrocytes in Cartilage Formation, Progression of Osteoarthritis and Cartilage Regeneration

    PubMed Central

    Akkiraju, Hemanth; Nohe, Anja

    2016-01-01

    Articular cartilage (AC) covers the diarthrodial joints and is responsible for the mechanical distribution of loads across the joints. The majority of its structure and function is controlled by chondrocytes that regulate Extracellular Matrix (ECM) turnover and maintain tissue homeostasis. Imbalance in their function leads to degenerative diseases like Osteoarthritis (OA). OA is characterized by cartilage degradation, osteophyte formation and stiffening of joints. Cartilage degeneration is a consequence of chondrocyte hypertrophy along with the expression of proteolytic enzymes. Matrix Metalloproteinases (MMPs) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS) are an example of these enzymes that degrade the ECM. Signaling cascades involved in limb patterning and cartilage repair play a role in OA progression. However, the regulation of these remains to be elucidated. Further the role of stem cells and mature chondrocytes in OA progression is unclear. The progress in cell based therapies that utilize Mesenchymal Stem Cell (MSC) infusion for cartilage repair may lead to new therapeutics in the long term. However, many questions are unanswered such as the efficacy of MSCs usage in therapy. This review focuses on the role of chondrocytes in cartilage formation and the progression of OA. Moreover, it summarizes possible alternative therapeutic approaches using MSC infusion for cartilage restoration. PMID:27347486

  4. Insulin-like growth factor-1 suspended in hyaluronan improves cartilage and subchondral cancellous bone repair in osteoarthritis of temporomandibular joint.

    PubMed

    Liu, X-W; Hu, J; Man, C; Zhang, B; Ma, Y-Q; Zhu, S-S

    2011-02-01

    This study sought to evaluate the effects of intra-articular injection of insulin-like growth factor-1 (IGF-1) suspended in hyaluronan (HA) on the cartilage and subchondral cancellous bone repair in osteoarthritis (OA) of the temporomandibular joint (TMJ). Disc perforation was performed bilaterally in rabbit TMJs to induce OA. Four groups of animals (n=12) received OA induction only, and either intra-articular HA injection alone, intra-articular IGF-1 injection alone, or a combination of HA and IGF-1 injection. All therapy was begun 4 weeks after OA induction. The animals were killed 12 or 24 weeks after the first injection, for histology and micro-CT examinations. Two additional animals were used as normal controls. Typical cartilage and subchondral cancellous bone lesions were observed in the OA group. No protective effect on cartilage and subchondral cancellous bone was found in the HA or IGF-1 alone groups. Better histological repair and nearly normal micro-architectural properties of the subchondral cancellous bone were observed in the HA+IGF-1 group compared with the HA or IGF-1 alone groups. HA may be used as an effective carrier for intra-articular injection of IGF-1 and the combination of HA/IGF-1 shows promise as a new rational approach to therapy of TMJ OA. PMID:21055904

  5. Bone Cysts After Osteochondral Allograft Repair of Cartilage Defects in Goats Suggest Abnormal Interaction Between Subchondral Bone and Overlying Synovial Joint Tissues

    PubMed Central

    Pallante-Kichura, Andrea L.; Cory, Esther; Bugbee, William D.; Sah, Robert L.

    2013-01-01

    The efficacy of osteochondral allografts (OCA) may be affected by osseous support of the articular cartilage, and thus affected by bone healing and remodeling in the OCA and surrounding host. Bone cysts, and their communication pathways, may be present in various locations after OCA insertion and reflect distinct pathogenic mechanisms. Previously, we analyzed the effect of OCA storage (FRESH, 4°C/14d, 4°C/28d, FROZEN) on cartilage quality in fifteen adult goats after 12 months in vivo. The objectives of this study were to further analyze OCA and contralateral non-operated (Non-Op) CONTROLS from the medial femoral condyle to (1) determine the effect of OCA storage on local subchondral (ScB) and trabecular (TB) bone structure, (2) characterize the location and structure of bone cysts and channels, and (3) assess the relationship between cartilage and bone properties. (1) Overall bone structure after OCA was altered compared to Non-Op, with OCA samples displaying bone cysts, ScB channels, and ScB roughening. ScB BV/TV in FROZEN OCA was lower than Non-Op and other OCA. TB BV/TV in FRESH, 4°C/14d, and 4°C/28d OCA did not vary compared to Non-Op, but BS/TV was lower. (2) OCA contained “basal” cysts, localized to deeper regions, some “subchondral” cysts, localized near the bone-cartilage interface, and some ScB channels. TB surrounding basal cysts exhibited higher BV/TV than Non-Op. (3) Basal cysts occurred (a) in isolation, (b) with subchondral cysts and ScB channels, (c) with ScB channels, or (d) with subchondral cysts, ScB channels, and ScB erosion. Deterioration of cartilage gross morphology was strongly associated with abnormal μCT bone structure. Evidence of cartilage-bone communication following OCA repair may favor fluid intrusion as a mechanism for subchondral cyst formation, while bone resorption at the graft-host interface without affecting overall bone and cartilage structure may favor bony contusion mechanism for basal cyst formation. These

  6. Bone cysts after osteochondral allograft repair of cartilage defects in goats suggest abnormal interaction between subchondral bone and overlying synovial joint tissues.

    PubMed

    Pallante-Kichura, Andrea L; Cory, Esther; Bugbee, William D; Sah, Robert L

    2013-11-01

    The efficacy of osteochondral allografts (OCAs) may be affected by osseous support of the articular cartilage, and thus affected by bone healing and remodeling in the OCA and surrounding host. Bone cysts, and their communication pathways, may be present in various locations after OCA insertion and reflect distinct pathogenic mechanisms. Previously, we analyzed the effect of OCA storage (FRESH, 4°C/14d, 4°C/28d, FROZEN) on cartilage quality in fifteen adult goats after 12months in vivo. The objectives of this study were to further analyze OCAs and contralateral non-operated (Non-Op) CONTROLS from the medial femoral condyle to (1) determine the effect of OCA storage on local subchondral bone (ScB) and trabecular bone (TB) structure, (2) characterize the location and structure of bone cysts and channels, and (3) assess the relationship between cartilage and bone properties. (1) Overall bone structure after OCAs was altered compared to Non-Op, with OCA samples displaying bone cysts, ScB channels, and ScB roughening. ScB BV/TV in FROZEN OCAs was lower than Non-Op and other OCAs. TB BV/TV in FRESH, 4°C/14d, and 4°C/28d OCAs did not vary compared to Non-Op, but BS/TV was lower. (2) OCAs contained "basal" cysts, localized to deeper regions, some "subchondral" cysts, localized near the bone-cartilage interface, and some ScB channels. TB surrounding basal cysts exhibited higher BV/TV than Non-Op. (3) Basal cysts occurred (a) in isolation, (b) with subchondral cysts and ScB channels, (c) with ScB channels, or (d) with subchondral cysts, ScB channels, and ScB erosion. Deterioration of cartilage gross morphology was strongly associated with abnormal μCT bone structure. Evidence of cartilage-bone communication following OCA repair may favor fluid intrusion as a mechanism for subchondral cyst formation, while bone resorption at the graft-host interface without affecting overall bone and cartilage structure may favor bony contusion mechanism for basal cyst formation. These

  7. Poroelastic response of articular cartilage by nanoindentation creep tests at different characteristic lengths.

    PubMed

    Taffetani, M; Gottardi, R; Gastaldi, D; Raiteri, R; Vena, P

    2014-07-01

    Nanoindentation is an experimental technique which is attracting increasing interests for the mechanical characterization of articular cartilage. In particular, time dependent mechanical responses due to fluid flow through the porous matrix can be quantitatively investigated by nanoindentation experiments at different penetration depths and/or by using different probe sizes. The aim of this paper is to provide a framework for the quantitative interpretation of the poroelastic response of articular cartilage subjected to creep nanoindentation tests. To this purpose, multiload creep tests using spherical indenters have been carried out on saturated samples of mature bovine articular cartilage achieving two main quantitative results. First, the dependence of indentation modulus in the drained state (at equilibrium) on the tip radius: a value of 500 kPa has been found using the large tip (400 μm radius) and of 1.7 MPa using the smaller one (25 μm). Secon, the permeability at microscopic scale was estimated at values ranging from 4.5×10(-16) m(4)/N s to 0.1×10(-16) m(4)/N s, from low to high equivalent deformation. Consistently with a poroelastic behavior, the size-dependent response of the indenter displacement disappears when characteristic size and permeability are accounted for. For comparison purposes, the same protocol was applied to intrinsically viscoelastic homogeneous samples of polydimethylsiloxane (PDMS): both indentation modulus and time response have been found size-independent. PMID:24814573

  8. Laryngeal muscle responses to mechanical displacement of the thyroid cartilage in humans

    PubMed Central

    Loucks, Torrey M. J.; Poletto, Christopher J.; Saxon, Keith G.; Ludlow, Christy L.

    2005-01-01

    Speakers may use laryngeal sensory feedback to adjust vocal fold tension and length before initiating voice. The mechanism for accurately initiating voice at an intended pitch is unknown, given the absence of laryngeal muscle spindles in animals and conflicting findings regarding their existence in humans. Previous reports of rapid changes in voice fundamental frequency following thyroid cartilage displacement suggest that changes in vocal fold length modulate laryngeal muscle contraction in humans. We tested the hypothesis that voice changes resulting from mechanical perturbation are due to rapid responses in the intrinsic laryngeal muscles. Hooked wire electrodes were used to record from the thyroarytenoid, cricothyroid, and sternothyroid muscles along with surface electrodes on the skin overlying the thyroid cartilage in 10 normal adults. Servomotor displacements produced consistent changes in the subjects’ vocal fundamental frequency at 70–80 ms, demonstrating changes in vocal fold length and tension. No simultaneous electromyographic responses occurred in the thyroarytenoid or cricothyroid muscles in any subjects. Instead, short-latency responses at 25–40 ms following stimulus onset occurred in the sternothyroid muscles, simultaneous with responses in the surface recordings. The sternothyroid responses may modulate long-latency changes in voice fundamental frequency (~150 ms). The absence of intrinsic laryngeal muscle responses is consistent with a lack of spindles in these muscles. Our results suggest that other sensory receptors, such as mucosal mechanoreceptors, provide feedback for voice control. PMID:15932961

  9. Altered responsiveness to TGF-β results in reduced Papss2 expression and alterations in the biomechanical properties of mouse articular cartilage

    PubMed Central

    2012-01-01

    Introduction Previous studies have indicated that transforming growth factor β (TGF-β) signaling has a critical role in cartilage homeostasis and repair, yet the mechanisms of TGF-β's chondroprotective effects are not known. Our objective in this study was to identify downstream targets of TGF-β that could act to maintain biochemical and biomechanical properties of cartilage. Methods Tibial joints from 20-week-old mice that express a dominant-negative mutation of the TGF-β type II receptor (DNIIR) were graded histologically for osteoarthritic changes and tested by indentation to evaluate their mechanical properties. To identify gene targets of TGF-β, microarray analysis was performed using bovine articular chondrocytes grown in micromass culture that were either treated with TGF-β or left untreated. Phosphoadenosine phosphosynthetase 2 (PAPSS2) was identified as a TGF-β-responsive gene. Papss2 expression is crucial for proper sulfation of cartilage matrix, and its deficiency causes skeletal defects in mice and humans that overlap with those seen in mice with mutations in TGF-β-signaling genes. Regulation of Papss2 was verified by real time RT-PCR and Western blot analyses. Alterations in sulfation of glycosaminoglycans were analyzed by critical electrolyte concentration and Alcian blue staining and immunofluorescence for chondroitin-4-sulfate, unsulfated chondroitin and the aggrecan core protein. Results DNIIR mutants showed reduced mechanical properties and osteoarthritis-like changes when compared to wild-type control mice. Microarray analysis identified a group of genes encoding matrix-modifying enzymes that were regulated by TGF-β. Papss2 was upregulated in bovine articular chondrocytes after treatment with TGF-β and downregulated in cartilage from DNIIR mice. Articular cartilage in DNIIR mice demonstrated reduced Alcian blue staining at critical electrolyte concentrations and reduced chondroitin-4-sulfate staining. Staining for unsulfated

  10. Sellar repair with autologous muscle and composite septal cartilage grafts for treatment of cerebrospinal fluid leakage following trans-sphenoidal pituitary surgery

    PubMed Central

    El Shazly, Ayman A.; El Wardany, Mohammed A.; Abo El Ezz, Tamer A.

    2016-01-01

    Context: Many reconstructive techniques have been proposed to prevent postoperative cerebrospinal fluid (CSF) leakage after trans-sphenoidal pituitary surgery. However, no total agreement has been reached to the best technique. Aim: Assessment of the efficacy of sellar repair with autologous muscle and composite septal cartilage grafts for treatment of intraoperative and delayed postoperative CSF leakage following trans-sphenoidal pituitary surgery without the use of postoperative external lumbar CSF drain. Study Design: This is a retrospective case series study, level IV evidence. Materials and Methods : Twenty three patients were involved in this study. Seventeen patients had intraoperative CSF leakage and were treated immediately by our technique. Six patients had postoperative CSF rhinorrhea and had delayed treatment with our technique after failure of conservative measures and external lumbar CSF drainage for more than three days. The technique involved intradural placement of autologous muscle graft supplemented with extradural composite septal cartilage graft, composed of a piece of the posterior cartilaginous septum with its covering mucoperichondrium on one side only to fit into the sellar defect as a double layer button. Results: CSF leak was of grade 1 in 6 patients (26.1%), grade 2 in 10 patients (43.5%) and grade 3 in 7 patients (30.4%). None of the patients in our study had postoperative CSF leak after the use of our technique during the follow up period (mean 24 ± 10.47 standard deviation months). None of the patients developed treatment-related complications. All the patients had well developed mucosal covering of the sellar defect after two months. Conclusion: Our technique of sellar repair by using autologous muscle and composite septal cartilage grafts is effective in treatment of intraoperative and delayed postoperative CSF leakage following trans-sphenoidal pituitary surgery without the use of postoperative external lumbar CSF drain even in

  11. Sellar repair with autologous muscle and composite septal cartilage grafts for treatment of cerebrospinal fluid leakage following trans-sphenoidal pituitary surgery

    PubMed Central

    El Shazly, Ayman A.; El Wardany, Mohammed A.; Abo El Ezz, Tamer A.

    2016-01-01

    Context: Many reconstructive techniques have been proposed to prevent postoperative cerebrospinal fluid (CSF) leakage after trans-sphenoidal pituitary surgery. However, no total agreement has been reached to the best technique. Aim: Assessment of the efficacy of sellar repair with autologous muscle and composite septal cartilage grafts for treatment of intraoperative and delayed postoperative CSF leakage following trans-sphenoidal pituitary surgery without the use of postoperative external lumbar CSF drain. Study Design: This is a retrospective case series study, level IV evidence. Materials and Methods : Twenty three patients were involved in this study. Seventeen patients had intraoperative CSF leakage and were treated immediately by our technique. Six patients had postoperative CSF rhinorrhea and had delayed treatment with our technique after failure of conservative measures and external lumbar CSF drainage for more than three days. The technique involved intradural placement of autologous muscle graft supplemented with extradural composite septal cartilage graft, composed of a piece of the posterior cartilaginous septum with its covering mucoperichondrium on one side only to fit into the sellar defect as a double layer button. Results: CSF leak was of grade 1 in 6 patients (26.1%), grade 2 in 10 patients (43.5%) and grade 3 in 7 patients (30.4%). None of the patients in our study had postoperative CSF leak after the use of our technique during the follow up period (mean 24 ± 10.47 standard deviation months). None of the patients developed treatment-related complications. All the patients had well developed mucosal covering of the sellar defect after two months. Conclusion: Our technique of sellar repair by using autologous muscle and composite septal cartilage grafts is effective in treatment of intraoperative and delayed postoperative CSF leakage following trans-sphenoidal pituitary surgery without the use of postoperative external lumbar CSF drain even in

  12. Resident mesenchymal progenitors of articular cartilage

    PubMed Central

    Candela, Maria Elena; Yasuhara, Rika; Iwamoto, Masahiro; Enomoto-Iwamoto, Motomi

    2015-01-01

    Articular cartilage has poor capacity of self-renewal and repair. Insufficient number and activity of resident mesenchymal (connective tissue) progenitors is likely one of the underlying reasons. Chondroprogenitors reside not only in the superficial zone of articular cartilage but also in other zones of articular cartilage and in the neighboring tissues, including perichondrium (groove of Ranvier), synovium and fat pad. These cells may respond to injury and contribute to articular cartilage healing. In addition, marrow stromal cells can migrate through subchondral bone when articular cartilage is damaged. We should develop drugs and methods that correctly stimulate resident progenitors for improvement of repair and inhibition of degenerative changes in articular cartilage. PMID:25179676

  13. Resident mesenchymal progenitors of articular cartilage.

    PubMed

    Candela, Maria Elena; Yasuhara, Rika; Iwamoto, Masahiro; Enomoto-Iwamoto, Motomi

    2014-10-01

    Articular cartilage has poor capacity of self-renewal and repair. Insufficient number and activity of resident mesenchymal (connective tissue) progenitors is likely one of the underlying reasons. Chondroprogenitors reside not only in the superficial zone of articular cartilage but also in other zones of articular cartilage and in the neighboring tissues, including perichondrium (groove of Ranvier), synovium and fat pad. These cells may respond to injury and contribute to articular cartilage healing. In addition, marrow stromal cells can migrate through subchondral bone when articular cartilage is damaged. We should develop drugs and methods that correctly stimulate resident progenitors for improvement of repair and inhibition of degenerative changes in articular cartilage. PMID:25179676

  14. 49 CFR 230.67 - Responsibility for inspection and repairs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders § 230.67 Responsibility for inspection and repairs. The steam locomotive owner and/or operator shall inspect and repair all steam locomotives and tenders under their control. All...

  15. 49 CFR 230.67 - Responsibility for inspection and repairs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders § 230.67 Responsibility for inspection and repairs. The steam locomotive owner and/or operator shall inspect and repair all steam locomotives and tenders under their control. All...

  16. 49 CFR 230.67 - Responsibility for inspection and repairs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders § 230.67 Responsibility for inspection and repairs. The steam locomotive owner and/or operator shall inspect and repair all steam locomotives and tenders under their control. All...

  17. 49 CFR 230.67 - Responsibility for inspection and repairs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders § 230.67 Responsibility for inspection and repairs. The steam locomotive owner and/or operator shall inspect and repair all steam locomotives and tenders under their control. All...

  18. Participation of DNA repair in the response to 5-fluorouracil

    PubMed Central

    Wyatt, Michael D.; Wilson, David M.

    2008-01-01

    The anti-metabolite 5-fluorouracil (5-FU) is employed clinically to manage solid tumors including colorectal and breast cancer. Intracellular metabolites of 5-FU can exert cytotoxic effects via inhibition of thymidylate synthetase, or through incorporation into RNA and DNA, events that ultimately activate apoptosis. In this review, we cover the current data implicating DNA repair processes in cellular responsiveness to 5-FU treatment. Evidence points to roles for base excision repair (BER) and mismatch repair (MMR). However, mechanistic details remain unexplained, and other pathways have not been exhaustively interrogated. Homologous recombination is of particular interest, because it resolves unrepaired DNA intermediates not properly dealt with by BER or MMR. Furthermore, crosstalk among DNA repair pathways and S-phase checkpoint signaling has not been examined. Ongoing efforts aim to design approaches and reagents that (i) approximate repair capacity and (ii) mediate strategic regulation of DNA repair in order to improve the efficacy of current anti-cancer treatments. PMID:18979208

  19. Lubricin reduces cartilage--cartilage integration.

    PubMed

    Schaefer, Dirk B; Wendt, David; Moretti, Matteo; Jakob, Marcel; Jay, Gregory D; Heberer, Michael; Martin, Ivan

    2004-01-01

    Cartilage integration in vivo does not occur, such that even cartilage fissures do not heal. This could be due not only to the limited access of chondrocytes to the wound, but also to exogenous factors. In this paper, we tested the hypothesis that lubricin, a lubricating protein physiologically present in the synovial fluid, reduces the integrative cartilage repair capacity. Disk/ring composites of bovine articular cartilage were prepared using concentric circular blades and cultured for 6 weeks with or without treatment with 250 microg/ml lubricin applied three times per week. Following culture, the percentage of contact area between the disks and the rings, as assessed by light microscopy, were equal in both groups. The adhesive strength of the integration interface, as assessed by push-out mechanical tests, was markedly and significantly lower in lubricin-treated specimens (2.5 kPa) than in the controls (28.7 kPa). Histological observation of Safranin-O stained cross-sections confirmed the reduced integration in the lubricin treated composites. Our findings suggest that the synovial milieu, by providing lubrication of cartilage surfaces, impairs cartilage--cartilage integration. PMID:15299281

  20. In Vitro Engineering of High Modulus Cartilage-Like Constructs

    PubMed Central

    Seedhom, Bahaa B.; Carey, Duane O.; Bulpitt, Andy J.; Treanor, Darren E.; Kirkham, Jennifer

    2016-01-01

    To date, the outcomes of cartilage repair have been inconsistent and have frequently yielded mechanically inferior fibrocartilage, thereby increasing the chances of damage recurrence. Implantation of constructs with biochemical composition and mechanical properties comparable to natural cartilage could be advantageous for long-term repair. This study attempted to create such constructs, in vitro, using tissue engineering principles. Bovine synoviocytes were seeded on nonwoven polyethylene terephthalate fiber scaffolds and cultured in chondrogenic medium for 4 weeks, after which uniaxial compressive loading was applied using an in-house bioreactor for 1 h per day, at a frequency of 1 Hz, for a further 84 days. The initial loading conditions, determined from the mechanical properties of the immature constructs after 4 weeks in chondrogenic culture, were strains ranging between 13% and 23%. After 56 days (sustained at 84 days) of loading, the constructs were stained homogenously with Alcian blue and for type-II collagen. Dynamic compressive moduli were comparable to the high end values for native cartilage and proportional to Alcian blue staining intensity. We suggest that these high moduli values were attributable to the bioreactor setup, which caused the loading regime to change as the constructs developed, that is, the applied stress and strain increased with construct thickness and stiffness, providing continued sufficient cell stimulation as further matrix was deposited. Constructs containing cartilage-like matrix with response to load similar to that of native cartilage could produce long-term effective cartilage repair when implanted. PMID:26850081

  1. Brief report: reconstruction of joint hyaline cartilage by autologous progenitor cells derived from ear elastic cartilage.

    PubMed

    Mizuno, Mitsuru; Kobayashi, Shinji; Takebe, Takanori; Kan, Hiroomi; Yabuki, Yuichiro; Matsuzaki, Takahisa; Yoshikawa, Hiroshi Y; Nakabayashi, Seiichiro; Ik, Lee Jeong; Maegawa, Jiro; Taniguchi, Hideki

    2014-03-01

    In healthy joints, hyaline cartilage covering the joint surfaces of bones provides cushioning due to its unique mechanical properties. However, because of its limited regenerative capacity, age- and sports-related injuries to this tissue may lead to degenerative arthropathies, prompting researchers to investigate a variety of cell sources. We recently succeeded in isolating human cartilage progenitor cells from ear elastic cartilage. Human cartilage progenitor cells have high chondrogenic and proliferative potential to form elastic cartilage with long-term tissue maintenance. However, it is unknown whether ear-derived cartilage progenitor cells can be used to reconstruct hyaline cartilage, which has different mechanical and histological properties from elastic cartilage. In our efforts to develop foundational technologies for joint hyaline cartilage repair and reconstruction, we conducted this study to obtain an answer to this question. We created an experimental canine model of knee joint cartilage damage, transplanted ear-derived autologous cartilage progenitor cells. The reconstructed cartilage was rich in proteoglycans and showed unique histological characteristics similar to joint hyaline cartilage. In addition, mechanical properties of the reconstructed tissues were higher than those of ear cartilage and equal to those of joint hyaline cartilage. This study suggested that joint hyaline cartilage was reconstructed from ear-derived cartilage progenitor cells. It also demonstrated that ear-derived cartilage progenitor cells, which can be harvested by a minimally invasive method, would be useful for reconstructing joint hyaline cartilage in patients with degenerative arthropathies.

  2. Repair of large full-thickness cartilage defect by activating endogenous peripheral blood stem cells and autologous periosteum flap transplantation combined with patellofemoral realignment.

    PubMed

    Fu, Wei-Li; Ao, Ying-Fang; Ke, Xiao-Yan; Zheng, Zhuo-Zhao; Gong, Xi; Jiang, Dong; Yu, Jia-Kuo

    2014-03-01

    Minimal-invasive procedure and one-step surgery offer autologous mesenchymal stem cells derived from peripheral blood (PB-MSCs) a promising prospective in the field of cartilage regeneration. We report a case of a 19-year-old male athlete of kickboxing with ICRS grade IV chondral lesions at the 60° region of lateral femoral trochlea, which was repaired by activating endogenous PB-MSCs plus autologous periosteum flap transplantation combined with correcting the patellofemoral malalignment. After a 7.5 year follow-up, the result showed that the patient returned to competitive kickboxing. Second-look under arthroscopy showed a smooth surface at 8 months postoperation. The IKDC 2000 subjective score, Lysholm score and Tegner score were 95, 98 and 9 respectively at the final follow up. CT and MRI evaluations showed a significant improvement compared with those of pre-operation.

  3. Long Intergenic Noncoding RNAs Mediate the Human Chondrocyte Inflammatory Response and Are Differentially Expressed in Osteoarthritis Cartilage

    PubMed Central

    Pearson, Mark J.; Philp, Ashleigh M.; Heward, James A.; Roux, Benoit T.; Walsh, David A.; Davis, Edward T.; Lindsay, Mark A.

    2016-01-01

    Objective To identify long noncoding RNAs (lncRNAs), including long intergenic noncoding RNAs (lincRNAs), antisense RNAs, and pseudogenes, associated with the inflammatory response in human primary osteoarthritis (OA) chondrocytes and to explore their expression and function in OA. Methods OA cartilage was obtained from patients with hip or knee OA following joint replacement surgery. Non‐OA cartilage was obtained from postmortem donors and patients with fracture of the neck of the femur. Primary OA chondrocytes were isolated by collagenase digestion. LncRNA expression analysis was performed by RNA sequencing (RNAseq) and quantitative reverse transcriptase–polymerase chain reaction. Modulation of lncRNA chondrocyte expression was achieved using LNA longRNA GapmeRs (Exiqon). Cytokine production was measured with Luminex. Results RNAseq identified 983 lncRNAs in primary human hip OA chondrocytes, 183 of which had not previously been identified. Following interleukin‐1β (IL‐1β) stimulation, we identified 125 lincRNAs that were differentially expressed. The lincRNA p50‐associated cyclooxygenase 2–extragenic RNA (PACER) and 2 novel chondrocyte inflammation–associated lincRNAs (CILinc01 and CILinc02) were differentially expressed in both knee and hip OA cartilage compared to non‐OA cartilage. In primary OA chondrocytes, these lincRNAs were rapidly and transiently induced in response to multiple proinflammatory cytokines. Knockdown of CILinc01 and CILinc02 expression in human chondrocytes significantly enhanced the IL‐1–stimulated secretion of proinflammatory cytokines. Conclusion The inflammatory response in human OA chondrocytes is associated with widespread changes in the profile of lncRNAs, including PACER, CILinc01, and CILinc02. Differential expression of CILinc01 and CIinc02 in hip and knee OA cartilage, and their role in modulating cytokine production during the chondrocyte inflammatory response, suggest that they may play an important role

  4. Nonlinear mechanical response of the extracellular matrix: learning from articular cartilage

    NASA Astrophysics Data System (ADS)

    Kearns, Sarah; Das, Moumita

    2015-03-01

    We study the mechanical structure-function relations in the extracellular matrix (ECM) with focus on nonlinear shear and compression response. As a model system, our study focuses on the ECM in articular cartilage tissue which has two major mechanobiological components: a network of the biopolymer collagen that acts as a stiff, reinforcing matrix, and a flexible aggrecan network that facilitates deformability. We model this system as a double network hydrogel made of interpenetrating networks of stiff and flexible biopolymers respectively. We study the linear and nonlinear mechanical response of the model ECM to shear and compression forces using a combination of rigidity percolation theory and energy minimization approaches. Our results may provide useful insights into the design principles of the ECM as well as biomimetic hydrogels that are mechanically robust and can, at the same time, easily adapt to cues in their surroundings.

  5. Human Articular Cartilage Progenitor Cells Are Responsive to Mechanical Stimulation and Adenoviral-Mediated Overexpression of Bone-Morphogenetic Protein 2

    PubMed Central

    Neumann, Alexander J.; Gardner, Oliver F. W.; Williams, Rebecca; Alini, Mauro; Archer, Charles W.; Stoddart, Martin J.

    2015-01-01

    Articular cartilage progenitor cells (ACPCs) represent a new and potentially powerful alternative cell source to commonly used cell sources for cartilage repair, such as chondrocytes and bone-marrow derived mesenchymal stem cells (MSCs). This is particularly due to the apparent resistance of ACPCs to hypertrophy. The current study opted to investigate whether human ACPCs (hACPCs) are responsive towards mechanical stimulation and/or adenoviral-mediated overexpression of bone morphogenetic protein 2 (BMP-2). hACPCs were cultured in fibrin-polyurethane composite scaffolds. Cells were cultured in a defined chondro-permissive medium, lacking exogenous growth factors. Constructs were cultured, for 7 or 28 days, under free-swelling conditions or with the application of complex mechanical stimulation, using a custom built bioreactor that is able to generate joint-like movements. Outcome parameters were quantification of BMP-2 and transforming growth factor beta 1 (TGF-β1) concentration within the cell culture medium, biochemical and gene expression analyses, histology and immunohistochemistry. The application of mechanical stimulation alone resulted in the initiation of chondrogenesis, demonstrating the cells are mechanoresponsive. This was evidenced by increased GAG production, lack of expression of hypertrophic markers and a promising gene expression profile (significant up-regulation of cartilaginous marker genes, specifically collagen type II, accompanied by no increase in the hypertrophic marker collagen type X or the osteogenic marker alkaline phosphatase). To further investigate the resistance of ACPCs to hypertrophy, overexpression of a factor associated with hypertrophic differentiation, BMP-2, was investigated. A novel, three-dimensional, transduction protocol was used to transduce cells with an adenovirus coding for BMP-2. Over-expression of BMP-2, independent of load, led to an increase in markers associated with hypertropy. Taken together ACPCs represent a

  6. Micromechanical response of articular cartilage to tensile load measured using nonlinear microscopy.

    PubMed

    Bell, J S; Christmas, J; Mansfield, J C; Everson, R M; Winlove, C P

    2014-06-01

    Articular cartilage (AC) is a highly anisotropic biomaterial, and its complex mechanical properties have been a topic of intense investigation for over 60 years. Recent advances in the field of nonlinear optics allow the individual constituents of AC to be imaged in living tissue without the need for exogenous contrast agents. Combining mechanical testing with nonlinear microscopy provides a wealth of information about microscopic responses to load. This work investigates the inhomogeneous distribution of strain in loaded AC by tracking the movement and morphological changes of individual chondrocytes using point pattern matching and Bayesian modeling. This information can be used to inform models of mechanotransduction and pathogenesis, and is readily extendable to various other connective tissues.

  7. In vitro targeted magnetic delivery and tracking of superparamagnetic iron oxide particles labeled stem cells for articular cartilage defect repair.

    PubMed

    Feng, Yong; Jin, Xuhong; Dai, Gang; Liu, Jun; Chen, Jiarong; Yang, Liu

    2011-04-01

    To assess a novel cell manipulation technique of tissue engineering with respect to its ability to augment superparamagnetic iron oxide particles (SPIO) labeled mesenchymal stem cells (MSCs) density at a localized cartilage defect site in an in vitro phantom by applying magnetic force. Meanwhile, non-invasive imaging techniques were use to track SPIO-labeled MSCs by magnetic resonance imaging (MRI). Human bone marrow MSCs were cultured and labeled with SPIO. Fresh degenerated human osteochondral fragments were obtained during total knee arthroplasty and a cartilage defect was created at the center. Then, the osteochondral fragments were attached to the sidewalls of culture flasks filled with phosphate-buffered saline (PBS) to mimic the human joint cavity. The SPIO-labeled MSCs were injected into the culture flasks in the presence of a 0.57 Tesla (T) magnetic force. Before and 90 min after cell targeting, the specimens underwent T2-weighted turbo spin-echo (SET2WI) sequence of 3.0 T MRI. MRI results were compared with histological findings. Macroscopic observation showed that SPIO-labeled MSCs were steered to the target region of cartilage defect. MRI revealed significant changes in signal intensity (P<0.01). HE staining exibited that a great number of MSCs formed a three-dimensional (3D) cell "sheet" structure at the chondral defect site. It was concluded that 0.57 T magnetic force permits spatial delivery of magnetically labeled MSCs to the target region in vitro. High-field MRI can serve as an very sensitive non-invasive technique for the visualization of SPIO-labeled MSCs.

  8. Combined effects of connective tissue growth factor-modified bone marrow-derived mesenchymal stem cells and NaOH-treated PLGA scaffolds on the repair of articular cartilage defect in rabbits.

    PubMed

    Zhu, Songsong; Zhang, Bi; Man, Cheng; Ma, Yongqing; Liu, Xianwen; Hu, Jing

    2014-04-01

    In cartilage tissue engineering using stem cells, it is important to stimulate proliferation and control the differentiation of stem cells to specific lineages. Here we reported a combined technique for articular cartilage repair, consisting of bone marrow mesenchymal stem cells (BMMSCs) transfected with connective tissue growth factor (CTGF) gene and NaOH-treated poly(lactic-co-glycolic) acid (PLGA) scaffolds. In the present study, BMMSCs or CTGF-modified BMMSCs seeded on PLGA or NaOH-treated PLGA scaffolds were incubated in vitro and NaOH-treated PLGA significantly stimulated proliferation of BMMSCs, while CTGF gene transfer promoted chondrogenic differentiation. The effects of the composite on the repair of cartilage defects were evaluated in rabbit knee joints in vivo. Full-thickness cartilage defects (diameter: 5 mm; depth: 3 mm) were created unilaterally in the patellar groove. Defects were either left empty (n = 18) or implanted with BMMSCs/PLGA (n = 18), BMMSCs/NaOH-treated PLGA (n = 18), or CTGF-modified BMMSCs/NaOH-treated PLGA (n = 18). The defect area was examined grossly, histologically, and mechanically at 6, 12, and 24 weeks postoperatively. Implanted cells were tracked using adeno-LacZ labeling at 6 weeks after implantation. Overall, the CTGF-modified BMMSCs/NaOH-treated PLGA group showed successful hyaline-like cartilage regeneration similar to normal cartilage, which was superior to the other groups using gross examination, qualitative and quantitative histology, and mechanical assessment. The in vivo viability of the implanted cells was demonstrated by their retention for 6 weeks after implantation. These findings suggested that a combination of CTGF-modified BMMSCs and NaOH-treated PLGA may be an alternative treatment for large osteochondral defects in high-loading sites.

  9. Combining Freshly Isolated Chondroprogenitor Cells from the Infrapatellar Fat Pad with a Growth Factor Delivery Hydrogel as a Putative Single Stage Therapy for Articular Cartilage Repair

    PubMed Central

    Ahearne, Mark; Liu, Yurong

    2014-01-01

    results of these in vitro studies do not provide strong evidence to support the use of selective substrate adhesion as a means to isolate chondroprogenitor cells, the findings demonstrate the potential of combining a growth factor delivery hydrogel and FI IFP cells as a single stage therapy for cartilage defect repair. PMID:24090441

  10. Cartilage Disorders

    MedlinePlus

    ... cartilage problems include Tears and injuries, such as sports injuries Genetic factors Other disorders, such as some types of arthritis Osteoarthritis results from breakdown of cartilage. NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

  11. Cell-based approaches to joint surface repair: a research perspective

    PubMed Central

    Roelofs, A.J.; Rocke, J.P.J.; De Bari, C.

    2013-01-01

    Summary Repair of lesions of the articular cartilage lining the joints remains a major clinical challenge. Surgical interventions include osteochondral autograft transfer and microfracture. They can provide some relief of symptoms to patients, but generally fail to durably repair the cartilage. Autologous chondrocyte implantation has thus far shown the most promise for the durable repair of cartilage, with long-term follow-up studies indicating improved structural and functional outcomes. However, disadvantages of this technique include the need for additional surgery, availability of sufficient chondrocytes for implantation, and maintenance of their phenotype during culture-expansion. Mesenchymal stem cells offer an attractive alternative cell-source for cartilage repair, due to their ease of isolation and amenability to ex vivo expansion while retaining stem cell properties. Preclinical and clinical studies have demonstrated the potential of mesenchymal stem cells to promote articular cartilage repair, but have also highlighted several key challenges. Most notably, the quality and durability of the repair tissue, its resistance to endochondral ossification, and its effective integration with the surrounding host tissue. In addition, challenges exist related to the heterogeneity of mesenchymal stem cell preparations and their quality-control, as well as optimising the delivery method. Finally, as our knowledge of the cellular and molecular mechanisms underlying articular cartilage repair increases, promising studies are emerging employing bioactive scaffolds or therapeutics that elicit an effective tissue repair response through activation and mobilisation of endogenous stem and progenitor cells. PMID:23598176

  12. Extracorporeal shockwave therapy promotes chondrogenesis in cartilage tissue engineering: A hypothesis based on previous evidence.

    PubMed

    Ji, Qiaodan; He, Chengqi

    2016-06-01

    The dearth of intrinsic regenerative capacity of articular cartilage makes it a challenge to deal with the cartilage defects. Among all the recommended clinical options, cartilage tissue engineering (CTE) which is highlighted of dominant features and less drawbacks for functional cartilage restoration, has been emphasized recently. Shock waves, a mode of therapeutic mechanical forces, utilized in extracorporeal shockwave therapy (ESWT), is hypothesized to enhance proliferation, chondrogenic differentiation, and cartilage extracellular matrix production of target cells seeded on bioactive scaffolds. The hypothesis is firstly based on cellular mechanotransduction by which cells convent the shockwave mechanical signals into biochemical responses via integrins, iron channels, cytoskeletal filaments, growth factor receptors and nuclei. Secondly, by modulating gene expression and up-regulating the release of various growth factors which are of vital importance in three-dimensional cartilage culture environment, ESWT holds a promising potential to favor the cell sources (e.g. chondrocytes and stem cells) to mimic the optimal functional cartilage. In all, on the basis of cellular mechanotransduction and previous evidence, the hypothesis is developed to support the beneficial effects of ESWT on chondrogenesis in CTE. If this hypothesis is confirmed, shockwaves may allow a better success in combination with other stimulating factors for cartilage repair. There is a paucity of studies investigating the assistant role of shockwave stimulation in CTE. Further research is required to elucidate the mechanisms, and explore effectiveness and appropriate protocols of this novel stimulative factor in cartilage tissue engineering.

  13. Extracorporeal shockwave therapy promotes chondrogenesis in cartilage tissue engineering: A hypothesis based on previous evidence.

    PubMed

    Ji, Qiaodan; He, Chengqi

    2016-06-01

    The dearth of intrinsic regenerative capacity of articular cartilage makes it a challenge to deal with the cartilage defects. Among all the recommended clinical options, cartilage tissue engineering (CTE) which is highlighted of dominant features and less drawbacks for functional cartilage restoration, has been emphasized recently. Shock waves, a mode of therapeutic mechanical forces, utilized in extracorporeal shockwave therapy (ESWT), is hypothesized to enhance proliferation, chondrogenic differentiation, and cartilage extracellular matrix production of target cells seeded on bioactive scaffolds. The hypothesis is firstly based on cellular mechanotransduction by which cells convent the shockwave mechanical signals into biochemical responses via integrins, iron channels, cytoskeletal filaments, growth factor receptors and nuclei. Secondly, by modulating gene expression and up-regulating the release of various growth factors which are of vital importance in three-dimensional cartilage culture environment, ESWT holds a promising potential to favor the cell sources (e.g. chondrocytes and stem cells) to mimic the optimal functional cartilage. In all, on the basis of cellular mechanotransduction and previous evidence, the hypothesis is developed to support the beneficial effects of ESWT on chondrogenesis in CTE. If this hypothesis is confirmed, shockwaves may allow a better success in combination with other stimulating factors for cartilage repair. There is a paucity of studies investigating the assistant role of shockwave stimulation in CTE. Further research is required to elucidate the mechanisms, and explore effectiveness and appropriate protocols of this novel stimulative factor in cartilage tissue engineering. PMID:27142133

  14. A Review of the Combination of Experimental Measurements and Fibril-Reinforced Modeling for Investigation of Articular Cartilage and Chondrocyte Response to Loading

    PubMed Central

    Wilson, Wouter; Isaksson, Hanna; Jurvelin, Jukka S.; Herzog, Walter; Korhonen, Rami K.

    2013-01-01

    The function of articular cartilage depends on its structure and composition, sensitively impaired in disease (e.g. osteoarthritis, OA). Responses of chondrocytes to tissue loading are modulated by the structure. Altered cell responses as an effect of OA may regulate cartilage mechanotransduction and cell biosynthesis. To be able to evaluate cell responses and factors affecting the onset and progression of OA, local tissue and cell stresses and strains in cartilage need to be characterized. This is extremely challenging with the presently available experimental techniques and therefore computational modeling is required. Modern models of articular cartilage are inhomogeneous and anisotropic, and they include many aspects of the real tissue structure and composition. In this paper, we provide an overview of the computational applications that have been developed for modeling the mechanics of articular cartilage at the tissue and cellular level. We concentrate on the use of fibril-reinforced models of cartilage. Furthermore, we introduce practical considerations for modeling applications, including also experimental tests that can be combined with the modeling approach. At the end, we discuss the prospects for patient-specific models when aiming to use finite element modeling analysis and evaluation of articular cartilage function, cellular responses, failure points, OA progression, and rehabilitation. PMID:23653665

  15. [Present status and perspective of articular cartilage regeneration].

    PubMed

    Wakitani, Shigeyuki

    2007-05-01

    Because the capacity of articular cartilage for repair is limited, defects are a major clinical problem, and there is at present no satisfactory clinical technique to regenerate cartilage defects. Current clinical practice involves the bone stimulation technique, which breaks subchondral bone to facilitate cartilage repair from bone marrow derived cells and cytokines. This consists of multiple perforations, abrasions, and micro-fractures. However, with this procedure, cartilage defects are repaired with fibrocartilage, which is known to be biochemically and biomechanically different from normal hyaline cartilage and degeneration occurs in the reparative tissue. Autologous chondrocyte implantation (ACI) for repair of human articular cartilage was reported in 1994, and approved by the USA Food and Drug Association in 1997. This procedure has been performed for more than 20000 people all over the world, but its effectiveness is still controversial. Mosaic plasty was explored in the 1990s. Using this procedure, we can repair defects with hyaline cartilage, but the donor site morbidity is unsolved. To explore a new method for cartilage repair, we transplanted autologous culture-expanded bone marrow mesenchymal cells into articular cartilage defects. Clinical symptoms were improred but the repair cartilage was not hyaline cartilage. Further improvement is required. Many investigations have been made in the search for better means of repair, including gene transduction and the addition of growth factors during cell culture. In addition to bone marrow mesenchymal cells, synovial cells, adipocytes, muscle cells, etc. have been evaluated.

  16. Contact models of repaired articular surfaces: influence of loading conditions and the superficial tangential zone.

    PubMed

    Owen, John R; Wayne, Jennifer S

    2011-07-01

    The superficial tangential zone (STZ) plays a significant role in normal articular cartilage's ability to support loads and retain fluids. To date, tissue engineering efforts have not replicated normal STZ function in cartilage repairs. This finite element study examined the STZ's role in normal and repaired articular surfaces under different contact conditions. Contact area and pressure distributions were allowed to change with time, tension-compression nonlinearity modeled collagen behavior in the STZ, and nonlinear geometry was incorporated to accommodate finite deformation. Responses to loading via impermeable and permeable rigid surfaces were compared to loading via normal cartilage, a more physiologic condition, anticipating the two rigid loading surfaces would bracket that of normal. For models loaded by normal cartilage, an STZ placed over the inferior repair region reduced the short-term axial compression of the articular surface by 15%, when compared to a repair without an STZ. Covering the repair with a normal STZ shifted the flow patterns and strain levels back toward that of normal cartilage. Additionally, reductions in von Mises stress (21%) and an increase in fluid pressure (13%) occurred in repair tissue under the STZ. This continues to show that STZ properties of sufficient quality are likely critical for the survival of transplanted constructs in vivo. However, response to loading via normal cartilage did not always fall within ranges predicted by the rigid surfaces. Use of more physiologic contact models is recommended for more accurate investigations into properties critical to the success of repair tissues.

  17. Inhomogeneous Response of Articular Cartilage: A Three-Dimensional Multiphasic Heterogeneous Study

    PubMed Central

    Manzano, Sara; Armengol, Monica; J. Price, Andrew; A. Hulley, Philippa; S. Gill, Harinderjit; Doblaré, Manuel

    2016-01-01

    Articular cartilage exhibits complex mechano-electrochemical behaviour due to its anisotropy, inhomogeneity and material non-linearity. In this work, the thickness and radial dependence of cartilage properties are incorporated into a 3D mechano-electrochemical model to explore the relevance of heterogeneity in the behaviour of the tissue. The model considers four essential phenomena: (i) osmotic pressure, (ii) convective and diffusive processes, (iii) chemical expansion and (iv) three-dimensional through-the-thickness heterogeneity of the tissue. The need to consider heterogeneity in computational simulations of cartilage behaviour and in manufacturing biomaterials mimicking this tissue is discussed. To this end, healthy tibial plateaus from pigs were mechanically and biochemically tested in-vitro. Heterogeneous properties were included in the mechano-electrochemical computational model to simulate tissue swelling. The simulation results demonstrated that swelling of the heterogeneous samples was significantly lower than swelling under homogeneous and isotropic conditions. Furthermore, there was a significant reduction in the flux of water and ions in the former samples. In conclusion, the computational model presented here can be considered as a valuable tool for predicting how the variation of cartilage properties affects its behaviour, opening up possibilities for exploring the requirements of cartilage-mimicking biomaterials for tissue engineering. Besides, the model also allows the establishment of behavioural patterns of swelling and of water and ion fluxes in articular cartilage. PMID:27327166

  18. Inhomogeneous Response of Articular Cartilage: A Three-Dimensional Multiphasic Heterogeneous Study.

    PubMed

    Manzano, Sara; Armengol, Monica; J Price, Andrew; A Hulley, Philippa; S Gill, Harinderjit; Doblaré, Manuel; Hamdy Doweidar, Mohamed

    2016-01-01

    Articular cartilage exhibits complex mechano-electrochemical behaviour due to its anisotropy, inhomogeneity and material non-linearity. In this work, the thickness and radial dependence of cartilage properties are incorporated into a 3D mechano-electrochemical model to explore the relevance of heterogeneity in the behaviour of the tissue. The model considers four essential phenomena: (i) osmotic pressure, (ii) convective and diffusive processes, (iii) chemical expansion and (iv) three-dimensional through-the-thickness heterogeneity of the tissue. The need to consider heterogeneity in computational simulations of cartilage behaviour and in manufacturing biomaterials mimicking this tissue is discussed. To this end, healthy tibial plateaus from pigs were mechanically and biochemically tested in-vitro. Heterogeneous properties were included in the mechano-electrochemical computational model to simulate tissue swelling. The simulation results demonstrated that swelling of the heterogeneous samples was significantly lower than swelling under homogeneous and isotropic conditions. Furthermore, there was a significant reduction in the flux of water and ions in the former samples. In conclusion, the computational model presented here can be considered as a valuable tool for predicting how the variation of cartilage properties affects its behaviour, opening up possibilities for exploring the requirements of cartilage-mimicking biomaterials for tissue engineering. Besides, the model also allows the establishment of behavioural patterns of swelling and of water and ion fluxes in articular cartilage. PMID:27327166

  19. The location-specific healing response of damaged articular cartilage after ACL reconstruction: short-term follow-up.

    PubMed

    Nakamura, Norimasa; Horibe, Shuji; Toritsuka, Yukiyoshi; Mitsuoka, Tomoki; Natsu-ume, Takashi; Yoneda, Kenji; Hamada, Masayuki; Tanaka, Yoshinari; Boorman, Richard S; Yoshikawa, Hideki; Shino, Konsei

    2008-09-01

    Although many different interventions have been proposed for treating cartilage lesions at the time of ACL reconstruction, the normal healing response of these injuries has not been well documented. To address this point, we compared the arthroscopic status of chondral lesions at the time of ACL reconstruction with that obtained at second-look arthroscopy. We hypothesized that there might be a location-specific difference in the healing response of damaged articular cartilage. Between September 1998 and March 2000, 383 patients underwent arthroscopically-assisted hamstring ACL reconstruction without any intervention to the articular cartilage. Among these patients, 84 patients underwent second-look arthroscopy (ranging from 6 to 52 months following initial surgery) and make up the population of the present study. Chondral injuries, left untreated at ACL reconstruction, were arthroscopically evaluated using the Outerbridge classification, and were again evaluated at second-look arthroscopy. At second-look arthroscopy, there was significant recovery of chondral lesions by Outerbridge grading on both the medial and lateral femoral condyles. Among the recovered chondral lesions, 69% of cases of the medial femoral condyle, 88% of cases of the lateral femoral condyle were partial thickness injuries (grade I and II). Conversely, there was no significant recovery of chondral lesions observed at the patello-femoral joint or tibial plateaus. Our study revealed that there was a location-specific difference in the natural healing response of chondral injury. Untreated cartilage lesions on the femoral condlyes had a superior healing response compared to those on the tibial plateaus, and in the patello-femoral joint.

  20. Growth plate cartilage shows different strain patterns in response to static versus dynamic mechanical modulation.

    PubMed

    Kaviani, Rosa; Londono, Irene; Parent, Stefan; Moldovan, Florina; Villemure, Isabelle

    2016-08-01

    Longitudinal growth of long bones and vertebrae occurs in growth plate cartilage. This process is partly regulated by mechanical forces, which are one of the underlying reasons for progression of growth deformities such as idiopathic adolescent scoliosis and early-onset scoliosis. This concept of mechanical modulation of bone growth is also exploited in the development of fusionless treatments of these deformities. However, the optimal loading condition for the mechanical modulation of growth plate remains to be identified. The objective of this study was to evaluate the effects of in vitro static versus dynamic modulation and of dynamic loading parameters, such as frequency and amplitude, on the mechanical responses and histomorphology of growth plate explants. Growth plate explants from distal ulnae of 4-week-old swines were extracted and randomly distributed among six experimental groups: baseline ([Formula: see text]), control ([Formula: see text]), static ([Formula: see text]) and dynamic ([Formula: see text]). For static and dynamic groups, mechanical modulation was performed in vitro using an Indexed CartiGen bioreactor. A stress relaxation test combined with confocal microscopy and digital image correlation was used to characterize the mechanical responses of each explant in terms of peak stress, equilibrium stress, equilibrium modulus of elasticity and strain pattern. Histomorphometrical measurements were performed on toluidine blue tissue sections using a semi-automatic custom-developed MATLAB toolbox. Results suggest that compared to dynamic modulation, static modulation changes the strain pattern of the tissue and thus is more detrimental for tissue biomechanics, while the histomorphological parameters are not affected by mechanical modulation. Also, under dynamic modulation, changing the frequency or amplitude does not affect the biomechanical response of the tissue. Results of this study will be useful in finding optimal and non-damaging parameters

  1. Growth plate cartilage shows different strain patterns in response to static versus dynamic mechanical modulation.

    PubMed

    Kaviani, Rosa; Londono, Irene; Parent, Stefan; Moldovan, Florina; Villemure, Isabelle

    2016-08-01

    Longitudinal growth of long bones and vertebrae occurs in growth plate cartilage. This process is partly regulated by mechanical forces, which are one of the underlying reasons for progression of growth deformities such as idiopathic adolescent scoliosis and early-onset scoliosis. This concept of mechanical modulation of bone growth is also exploited in the development of fusionless treatments of these deformities. However, the optimal loading condition for the mechanical modulation of growth plate remains to be identified. The objective of this study was to evaluate the effects of in vitro static versus dynamic modulation and of dynamic loading parameters, such as frequency and amplitude, on the mechanical responses and histomorphology of growth plate explants. Growth plate explants from distal ulnae of 4-week-old swines were extracted and randomly distributed among six experimental groups: baseline ([Formula: see text]), control ([Formula: see text]), static ([Formula: see text]) and dynamic ([Formula: see text]). For static and dynamic groups, mechanical modulation was performed in vitro using an Indexed CartiGen bioreactor. A stress relaxation test combined with confocal microscopy and digital image correlation was used to characterize the mechanical responses of each explant in terms of peak stress, equilibrium stress, equilibrium modulus of elasticity and strain pattern. Histomorphometrical measurements were performed on toluidine blue tissue sections using a semi-automatic custom-developed MATLAB toolbox. Results suggest that compared to dynamic modulation, static modulation changes the strain pattern of the tissue and thus is more detrimental for tissue biomechanics, while the histomorphological parameters are not affected by mechanical modulation. Also, under dynamic modulation, changing the frequency or amplitude does not affect the biomechanical response of the tissue. Results of this study will be useful in finding optimal and non-damaging parameters

  2. Resurfacing Damaged Articular Cartilage to Restore Compressive Properties

    PubMed Central

    Grenier, Stephanie; Donnelly, Patrick E.; Gittens, Jamila; Torzilli, Peter A.

    2014-01-01

    Surface damage to articular cartilage is recognized as the initial underlying process causing the loss of mechanical function in early-stage osteoarthritis. In this study, we developed structure-modifying treatments to potentially prevent, stabilize or reverse the loss in mechanical function. Various polymers (chondroitin sulfate, carboxymethylcellulose, sodium hyaluronate) and photoinitiators (riboflavin, irgacure 2959) were applied to the surface of collagenase-degraded cartilage and crosslinked in situ using UV light irradiation. While matrix permeability and deformation significantly increased following collagenase-induced degradation of the superficial zone, resurfacing using tyramine-substituted sodium hyaluronate and riboflavin decreased both values to a level comparable to that of intact cartilage. Repetitive loading of resurfaced cartilage showed minimal variation in the mechanical response over a 7 day period. Cartilage resurfaced using a low concentration of riboflavin had viable cells in all zones while a higher concentration resulted in a thin layer of cell death in the uppermost superficial zone. Our approach to repair surface damage initiates a new therapeutic advance in the treatment of injured articular cartilage with potential benefits that include enhanced mechanical properties, reduced susceptibility to enzymatic degradation and reduced adhesion of macrophages. PMID:25468298

  3. Alterations in periarticular bone and cross talk between subchondral bone and articular cartilage in osteoarthritis

    PubMed Central

    2012-01-01

    The articular cartilage and the subchondral bone form a biocomposite that is uniquely adapted to the transfer of loads across the diarthrodial joint. During the evolution of the osteoarthritic process biomechanical and biological processes result in alterations in the composition, structure and functional properties of these tissues. Given the intimate contact between the cartilage and bone, alterations of either tissue will modulate the properties and function of the other joint component. The changes in periarticular bone tend to occur very early in the development of OA. Although chondrocytes also have the capacity to modulate their functional state in response to loading, the capacity of these cells to repair and modify their surrounding extracellular matrix is relatively limited in comparison to the adjacent subchondral bone. This differential adaptive capacity likely underlies the more rapid appearance of detectable skeletal changes in OA in comparison to the articular cartilage. The OA changes in periarticular bone include increases in subchondral cortical bone thickness, gradual decreases in subchondral trabeular bone mass, formation of marginal joint osteophytes, development of bone cysts and advancement of the zone of calcified cartilage between the articular cartilage and subchondral bone. The expansion of the zone of calcified cartilage contributes to overall thinning of the articular cartilage. The mechanisms involved in this process include the release of soluble mediators from chondrocytes in the deep zones of the articular cartilage and/or the influences of microcracks that have initiated focal remodeling in the calcified cartilage and subchondral bone in an attempt to repair the microdamage. There is the need for further studies to define the pathophysiological mechanisms involved in the interaction between subchondral bone and articular cartilage and for applying this information to the development of therapeutic interventions to improve the

  4. Response of base excision repair enzymes to complex DNA lesions.

    PubMed

    Weinfeld, M; Rasouli-Nia, A; Chaudhry, M A; Britten, R A

    2001-11-01

    There is now increasing evidence that ionizing radiation generates complex DNA damage, i.e. two or more lesions--single-strand breaks or modified nucleosides--located within one to two helical turns on the same strand or on opposite strands. Double-strand breaks are the most readily recognizable clustered lesions, but they may constitute a relatively minor fraction of the total. It is anticipated that clustered lesions may play a significant role in cellular response to ionizing radiation since they may present a major challenge to the DNA repair machinery. The degree of lesion complexity increases with increasing LET. This has potential implications for space travel because of exposure to high-LET cosmic radiation. It is therefore critical that we begin to understand the consequences of such damaged sites, including their influence on DNA repair enzymes. This paper presents a short review of our current knowledge of the action of purified DNA repair enzymes belonging to the base excision repair pathway, including DNA glycosylases and apurinic/apyrimidinic endonucleases, on model complex lesions.

  5. Chondrocyte IGF-1 receptor expression and responsiveness to IGF-1 stimulation in mouse articular cartilage during various phases of experimentally induced arthritis.

    PubMed Central

    Verschure, P J; van Marle, J; Joosten, L A; van den Berg, W B

    1995-01-01

    OBJECTIVE--To examine the distribution of insulin like growth factor-1 (IGF-1) receptors and the biological response to IGF-1 stimulation in articular cartilage of normal mouse knee joints and arthritic joints taken at various stages of experimentally induced arthritis. METHODS--In situ IGF-1 receptor expression and responsiveness to IGF-1 stimulation were examined in murine articular cartilage at different phases in two models of experimentally induced arthritis. IGF-1 receptor expression was visualised in joint sections with the use of anti-IGF-1 receptor antibodies and quantified by confocal laser scanning microscopy. Chondrocyte proteoglycan (PG) synthesis was measured by incorporation of 35S-sulphate. RESULTS--In control cartilage, the majority of IGF-1 receptors were found on chondrocytes localised in the middle and deeper zones of the cartilage, whereas receptor expression in surface zone chondrocytes was very low. During culture of normal articular cartilage, IGF-1 was able to maintain chondrocyte PG synthesis at the in vivo level. Concurrently with the development of arthritis, cartilage lost its capacity to react to IGF-1, but IGF-1 stimulation recovered when the inflammatory response waned. Shortly after induction of arthritis, IGF-1 receptor expression initially declined, but it had returned to normal levels by day 1 and remained increased thereafter. CONCLUSION--The distribution of IGF-1 receptor expression in the different zones of normal articular cartilage reflects IGF-1 stimulation and metabolic activity of chondrocytes in these layers. This correlation is disturbed in arthritic cartilage, suggesting inadequate or overruled signalling. Images PMID:7677441

  6. Effect of Glutaraldehyde Fixation on the Frictional Response of Immature Bovine Articular Cartilage Explants

    PubMed Central

    Oungoulian, Sevan R.; Hehir, Kristin E.; Zhu, Kaicen; Willis, Callen E.; Marinescu, Anca G.; Merali, Natasha; Ahmad, Christopher S.; Hung, Clark T.; Ateshian, Gerard A.

    2014-01-01

    This study examined functional properties and biocompatibility of glutaraldehyde-fixed bovine articular cartilage over several weeks of incubation at body temperature to investigate its potential use as a resurfacing material in joint arthroplasty. In the first experiment, treated cartilage disks were fixed using 0.02, 0.20 and 0.60 percent glutaraldehyde for 24 h then incubated, along with an untreated control group, in saline for up to 28 days at 37 °C. Both the equilibrium compressive and tensile moduli increased nearly twofold in treated samples compared to day 0 control, and remained at that level from day 1 to 28; the equilibrium friction coefficient against glass rose nearly twofold immediately after fixation (day 1) but returned to control values after day 7. Live explants co-cultured with fixed explants showed no quantitative difference in cell viability over 28 days. In general, no significant differences were observed between 0.20 and 0.60 percent groups, so 0.20 percent was deemed sufficient for complete fixation. In the second experiment, cartilage-on-cartilage frictional measurements were performed under a migrating contact configuration. In the treated group, one explant was fixed using 0.20 percent glutaraldehyde while the apposing explant was left untreated; in the control group both explants were left untreated. From day 1 to 28, the treated group exhibited either no significant difference or slightly lower friction coefficient than the untreated group. These results suggest that a properly titrated glutaraldehyde treatment can reproduce the desired functional properties of native articular cartilage and maintain these properties for at least 28 days at body temperature. PMID:24332617

  7. Recent Advances in Cartilage Tissue Engineering: From the Choice of Cell Sources to the Use of Bioreactors

    NASA Astrophysics Data System (ADS)

    Martin, Ivan; Démarteau, Olivier; Braccini, Alessandra

    Grafting engineered cartilage tissues represents a promising approach for the repair of joint injuries. Recent animal experiments have demonstrated that tissues engineered by culturing chondrocytes on 3D scaffolds in bioreactors provide functional templates for orderly repair of large osteochondral lesions. To date, however, a reproducible generation of uniform cartilage tissues of predefined size starting from adult human cells has not been achieved. In this paper we review some of the recent advances and challenges ahead in the identification of appropriate (i) cell sources, (ii) bioactive factors, (iii) 3D scaffolds and (iv) bioreactors for human cartilage tissue engineering. We also present an example of how integrated efforts in these different areas can help addressing fundamental questions and advancing the field of cartilage tissue engineering towards clinical use. The presented experiment demonstrates that human nasal chondrocytes are responsive to dynamic loading and thus could be further investigated as a cell source for implantation in a joint environment.

  8. Ihha induces hybrid cartilage-bone cells during zebrafish jawbone regeneration.

    PubMed

    Paul, Sandeep; Schindler, Simone; Giovannone, Dion; de Millo Terrazzani, Alexandra; Mariani, Francesca V; Crump, J Gage

    2016-06-15

    The healing of bone often involves a cartilage intermediate, yet how such cartilage is induced and utilized during repair is not fully understood. By studying a model of large-scale bone regeneration in the lower jaw of adult zebrafish, we show that chondrocytes are crucial for generating thick bone during repair. During jawbone regeneration, we find that chondrocytes co-express genes associated with osteoblast differentiation and produce extensive mineralization, which is in marked contrast to the behavior of chondrocytes during facial skeletal development. We also identify the likely source of repair chondrocytes as a population of Runx2(+)/Sp7(-) cells that emanate from the periosteum, a tissue that normally contributes only osteoblasts during homeostasis. Analysis of Indian hedgehog homolog a (ihha) mutants shows that the ability of periosteal cells to generate cartilage in response to injury depends on a repair-specific role of Ihha in the induction as opposed to the proliferation of chondrocytes. The large-scale regeneration of the zebrafish jawbone thus employs a cartilage differentiation program distinct from that seen during development, with the bone-forming potential of repair chondrocytes potentially due to their derivation from osteogenic cells in the periosteum. PMID:27122168

  9. Cellular and Matrix Response of the Mandibular Condylar Cartilage to Botulinum Toxin

    PubMed Central

    Dutra, Eliane H.; O’ Brien, Mara H.; Lima, Alexandro; Kalajzic, Zana; Tadinada, Aditya; Nanda, Ravindra; Yadav, Sumit

    2016-01-01

    Objectives To evaluate the cellular and matrix effects of botulinum toxin type A (Botox) on mandibular condylar cartilage (MCC) and subchondral bone. Materials and Methods Botox (0.3 unit) was injected into the right masseter of 5-week-old transgenic mice (Col10a1-RFPcherry) at day 1. Left side masseter was used as intra-animal control. The following bone labels were intraperitoneally injected: calcein at day 7, alizarin red at day 14 and calcein at day 21. In addition, EdU was injected 48 and 24 hours before sacrifice. Mice were sacrificed 30 days after Botox injection. Experimental and control side mandibles were dissected and examined by x-ray imaging and micro-CT. Subsequently, MCC along with the subchondral bone was sectioned and stained with tartrate resistant acid phosphatase (TRAP), EdU, TUNEL, alkaline phosphatase, toluidine blue and safranin O. In addition, we performed immunohistochemistry for pSMAD and VEGF. Results Bone volume fraction, tissue density and trabecular thickness were significantly decreased on the right side of the subchondral bone and mineralized cartilage (Botox was injected) when compared to the left side. There was no significant difference in the mandibular length and condylar head length; however, the condylar width was significantly decreased after Botox injection. Our histology showed decreased numbers of Col10a1 expressing cells, decreased cell proliferation and increased cell apoptosis in the subchondral bone and mandibular condylar cartilage, decreased TRAP activity and mineralization of Botox injected side cartilage and subchondral bone. Furthermore, we observed reduced proteoglycan and glycosaminoglycan distribution and decreased expression of pSMAD 1/5/8 and VEGF in the MCC of the Botox injected side in comparison to control side. Conclusion Injection of Botox in masseter muscle leads to decreased mineralization and matrix deposition, reduced chondrocyte proliferation and differentiation and increased cell apoptosis in the

  10. New insights in wound response and repair of epithelium.

    PubMed

    Chi, Cheryl; Trinkaus-Randall, Vickery

    2013-05-01

    Epithelial wounds usually heal relatively quickly, but repair may be impaired by environmental stressors, such as hypoxic or diabetic states, rendering patients vulnerable to a number of corneal pathologies. Though this response appears simple, at first, years of research have uncovered the complicated biochemical pathways coordinating the wound healing response. Here, we investigate signaling cascades and individual proteins involved in the corneal epithelium's self-repair. We will explore how an epithelial cell migrates across the wound bed and attaches itself to its new post-injury surroundings, including its neighboring cells and the basement membrane, through focal adhesions and hemidesmosomes. We will also discuss how the cell coordinates this motion physiologically, through calcium signaling and protein phosphorylation, focusing on the communication through purinergic, glutamatergic, and growth factor receptors. Many of these aspects reflect and can be extended to similar epithelial surfaces, and can be used to facilitate wound healing in patients with various underlying pathologies. The collective library of laboratory and clinical research done around the world has demonstrated how important precise regulation of these processes is in order for the injured corneal epithelium to properly heal.

  11. Tissue engineering strategies to study cartilage development, degeneration and regeneration.

    PubMed

    Bhattacharjee, Maumita; Coburn, Jeannine; Centola, Matteo; Murab, Sumit; Barbero, Andrea; Kaplan, David L; Martin, Ivan; Ghosh, Sourabh

    2015-04-01

    Cartilage tissue engineering has primarily focused on the generation of grafts to repair cartilage defects due to traumatic injury and disease. However engineered cartilage tissues have also a strong scientific value as advanced 3D culture models. Here we first describe key aspects of embryonic chondrogenesis and possible cell sources/culture systems for in vitro cartilage generation. We then review how a tissue engineering approach has been and could be further exploited to investigate different aspects of cartilage development and degeneration. The generated knowledge is expected to inform new cartilage regeneration strategies, beyond a classical tissue engineering paradigm.

  12. Engineering Cartilage

    MedlinePlus

    ... Method Builds Bone Lab-Grown Kidneys Function in Rats Cartilage: The Key to Healthy Joints Fast Facts ... Popular Stories An expanded map of the human brain How breast cancers resist chemotherapy Stem cells grown ...

  13. Potential regulation of cartilage metabolism in osteoarthritis by fibronectin fragments.

    PubMed

    Homandberg, G A

    1999-10-15

    There are few candidates for biochemical pathways that either initiate or amplify catabolic processes involved in osteoarthritis (OA). Perhaps, one of the most likely sources for such pathways may be within the extracellular matrix itself. This review focuses on an example of how specific degradation products of the extracellular matrix of cartilage, produced during proteolytic damage, have the potential to enhance OA-like processes. In this example, these products can induce or activate other factors, such as catabolic cytokines, that amplify the damage. The damage, in turn, enhances levels of the degradation products themselves, as in a positive feedback loop. Since these products are derived from the cartilage matrix, they could be considered barometers of the health of the cartilage that signal to the chondrocyte, through outside to inside signaling, the health or status of the surrounding matrix. The best example and most characterized system is that of fragments of the matrix protein, fibronectin (Fn), although as discussed later, other recently discovered fragment systems may also have the potential to regulate cartilage metabolism. In the case of Fn fragments (Fn-fs), the Fn-fs enhance levels of catabolic cytokines as in OA and, thus, are potentially earlier damage mediators than catabolic cytokines. The Fn-fs up-regulate matrix metalloproteinase (MMP) expression, significantly enhance degradation and loss of proteoglycan (PG) from cartilage and temporarily suppress PG synthesis, all events observed in OA. However, this Fn-f system may be involved in normal cartilage homeostasis as well. For example, low concentrations of Fn-fs enhance anabolic activities and could play a role in normal homeostasis. This system may also be involved in not only amplifying damage but also coupling damage to repair. For example, high concentrations of Fn-fs that might arise in OA temporarily offset the anabolic response of lower Fn-f concentrations and cause short

  14. Potential regulation of cartilage metabolism in osteoarthritis by fibronectin fragments.

    PubMed

    Homandberg, G A

    1999-10-15

    There are few candidates for biochemical pathways that either initiate or amplify catabolic processes involved in osteoarthritis (OA). Perhaps, one of the most likely sources for such pathways may be within the extracellular matrix itself. This review focuses on an example of how specific degradation products of the extracellular matrix of cartilage, produced during proteolytic damage, have the potential to enhance OA-like processes. In this example, these products can induce or activate other factors, such as catabolic cytokines, that amplify the damage. The damage, in turn, enhances levels of the degradation products themselves, as in a positive feedback loop. Since these products are derived from the cartilage matrix, they could be considered barometers of the health of the cartilage that signal to the chondrocyte, through outside to inside signaling, the health or status of the surrounding matrix. The best example and most characterized system is that of fragments of the matrix protein, fibronectin (Fn), although as discussed later, other recently discovered fragment systems may also have the potential to regulate cartilage metabolism. In the case of Fn fragments (Fn-fs), the Fn-fs enhance levels of catabolic cytokines as in OA and, thus, are potentially earlier damage mediators than catabolic cytokines. The Fn-fs up-regulate matrix metalloproteinase (MMP) expression, significantly enhance degradation and loss of proteoglycan (PG) from cartilage and temporarily suppress PG synthesis, all events observed in OA. However, this Fn-f system may be involved in normal cartilage homeostasis as well. For example, low concentrations of Fn-fs enhance anabolic activities and could play a role in normal homeostasis. This system may also be involved in not only amplifying damage but also coupling damage to repair. For example, high concentrations of Fn-fs that might arise in OA temporarily offset the anabolic response of lower Fn-f concentrations and cause short

  15. SUMO-mediated regulation of DNA damage repair and responses

    PubMed Central

    Sarangi, Prabha; Zhao, Xiaolan

    2015-01-01

    Sumoylation plays important roles during DNA damage repair and responses. Recent broad-scope and substrate-based studies have shed light on the regulation and significance of sumoylation during these processes. An emerging paradigm is that sumoylation of many DNA metabolism proteins is controlled by DNA engagement. Such “on-site modification” can explain low substrate modification levels and has important implications in sumoylation mechanisms and effects. New studies also suggest that sumoylation can regulate a process through an ensemble effect or via major substrates. Additionally, we describe new trends in the functional effects of sumoylation, such as bi-directional changes in biomolecule binding and multi-level coordination with other modifications. These emerging themes and models will stimulate our thinking and research in sumoylation and genome maintenance. PMID:25778614

  16. Leukocyte and Platelet Rich Plasma (L-PRP) Versus Leukocyte and Platelet Rich Fibrin (L-PRF) For Articular Cartilage Repair of the Knee: A Comparative Evaluation in an Animal Model

    PubMed Central

    Kazemi, Davoud; Fakhrjou, Ashraf

    2015-01-01

    Background: Articular cartilage injuries of the knee are among the most debilitating injuries leading to osteoarthritis due to limited regenerative capability of cartilaginous tissue. The use of platelet concentrates containing necessary growth factors for cartilage healing has recently emerged as a new treatment method. Objectives: The efficacy of two types of different platelet concentrates were compared in the treatment of acute articular cartilage injuries of the knee in an animal model. Materials and Methods: Eighteen adult Iranian mixed breed male dogs were used to conduct this experimental study. Full thickness articular cartilage defects (diameter 6 mm, depth 5 mm) were created in the weight bearing area of femoral condyles of both hind limbs in all dogs (n = 72). Twelve dogs were randomly selected to receive treatment and their right and left hind limb defects were treated by L-PRP and L-PRF implantation respectively, while no treatment was undertaken in six other dogs as controls. The animals were euthanized at 4, 16 and 24 weeks following surgery and the resultant repair tissue was investigated macroscopically and microscopically. At each sampling time, 4 treated dogs and 2 control dogs were euthanized, therefore 8 defects per group were evaluated. Results: Mean macroscopic scores of the treated defects were higher than the controls at all sampling times with significant differences (P < 0.05) observed between L-PRF treated and control defects (10.13 vs. 8.37) and L-PRP treated and control defects (10 vs. 8.5) at 4 and 16 weeks, respectively. A similar trend in mean total microscopic scores was observed with a significant difference (P < 0.05) between L-PRP treated and control defects at 4 (9.87 vs. 7.62) and 16 (13.38 vs. 11) weeks. No significant difference was observed between the platelet concentrate treated defects in either mean macroscopic scores or mean total microscopic scores. Conclusions: Both L-PRP and L-PRF could be used to effectively

  17. Use of collagen scaffold and autologous bone marrow concentrate as a one-step cartilage repair in the knee: histological results of second-look biopsies at 1 year follow-up.

    PubMed

    Gigante, A; Calcagno, S; Cecconi, S; Ramazzotti, D; Manzotti, S; Enea, D

    2011-01-01

    Chondral articular defects are a key concern in orthopaedic surgery. To overcome the disadvantages of autologous chondrocyte implantation (ACI) and to improve the outcomes of autologous matrix-induced chondrogenesis (AMIC), the latter technique is currently augmented with bone marrow concentrate injected under or seeded onto the scaffold. However, to date, only a little is known about histological outcomes of either the AMIC technique or AMIC associated with bone marrow concentrate. This study aimed to evaluate the quality of the repair tissue obtained from biopsies harvested during second-look arthroscopy after arthroscopic AMIC augmented with bone marrow concentrate. We analysed five second-look core biopsies harvested at 12 months follow-up. At the time of biopsy the surgeon reported the quality of the repair tissue using the standard ICRS Cartilage Repair Assessment (CRA). Every biopsy together with patient data was sent to our centre to undergo blind histological evaluation (ICRS II Visual Histological Assessment Scale) and data analysis. Five asymptomatic patients (mean age 43.4 years) had isolated lesions (mean size was 3.7 cm2) at the medial femoral condyle. All the implants appeared nearly normal (ICRS CRA) at arthroscopic evaluation and had a mean overall histological (ICRS II) of 59.8±14,5. Hyaline-like matrix was found in only one case, a mixture of hyaline/fibrocartilage was found in one case and fibrocartilage was found three cases. Our clinical and histological data suggest that this procedure achieved a nearly normal arthroscopic appearance and a satisfactory repair tissue, which was possibly still maturing at 12 months follow-up. Further studies are needed to understand the true potential of one-step procedures in the repair of focal chondral lesions in the knee.

  18. Articular cartilage biochemistry

    SciTech Connect

    Kuettner, K.E.; Schleyerbach, R.; Hascall, V.C.

    1986-01-01

    This book contains six parts, each consisting of several papers. The part titles are: Cartilage Matrix Components; Biosynthesis and Characterization of Cartilage--Specific Matrix Components and Events; Cartilage Metabolism; In Vitro Studies of Articular Cartilage Metabolism; Normal and Pathologic Metabolism of Cartilage; and Destruction of the Articular Cartilage in Rheumatoid Diseases. Some of the paper topics are: magnetic resonance imaging; joint destruction; age-related changes; proteoglycan structure; and biosynthesis of cartilage proteoglycan.

  19. Multiscale Mechanics of Articular Cartilage: Potentials and Challenges of Coupling Musculoskeletal, Joint, and Microscale Computational Models

    PubMed Central

    Halloran, J. P.; Sibole, S.; van Donkelaar, C. C.; van Turnhout, M. C.; Oomens, C. W. J.; Weiss, J. A.; Guilak, F.; Erdemir, A.

    2012-01-01

    Articular cartilage experiences significant mechanical loads during daily activities. Healthy cartilage provides the capacity for load bearing and regulates the mechanobiological processes for tissue development, maintenance, and repair. Experimental studies at multiple scales have provided a fundamental understanding of macroscopic mechanical function, evaluation of the micromechanical environment of chondrocytes, and the foundations for mechanobiological response. In addition, computational models of cartilage have offered a concise description of experimental data at many spatial levels under healthy and diseased conditions, and have served to generate hypotheses for the mechanical and biological function. Further, modeling and simulation provides a platform for predictive risk assessment, management of dysfunction, as well as a means to relate multiple spatial scales. Simulation-based investigation of cartilage comes with many challenges including both the computational burden and often insufficient availability of data for model development and validation. This review outlines recent modeling and simulation approaches to understand cartilage function from a mechanical systems perspective, and illustrates pathways to associate mechanics with biological function. Computational representations at single scales are provided from the body down to the microstructure, along with attempts to explore multiscale mechanisms of load sharing that dictate the mechanical environment of the cartilage and chondrocytes. PMID:22648577

  20. Tensorial electrokinetics in articular cartilage.

    PubMed

    Reynaud, Boris; Quinn, Thomas M

    2006-09-15

    Electrokinetic phenomena contribute to biomechanical functions of articular cartilage and underlie promising methods for early detection of osteoarthritic lesions. Although some transport properties, such as hydraulic permeability, are known to become anisotropic with compression, the direction-dependence of cartilage electrokinetic properties remains unknown. Electroosmosis experiments were therefore performed on adult bovine articular cartilage samples, whereby fluid flows were driven by electric currents in directions parallel and perpendicular to the articular surface of statically compressed explants. Magnitudes of electrokinetic coefficients decreased slightly with compression (from approximately -7.5 microL/As in the range of 0-20% compression to -6.0 microL/As in the 35-50% range) consistent with predictions of microstructure-based models of cartilage material properties. However, no significant dependence on direction of the electrokinetic coupling coefficient was detected, even for conditions where the hydraulic permeability tensor is known to be anisotropic. This contrast may also be interpreted using microstructure-based models, and provides insights into structure-function relationships in cartilage extracellular matrix and physical mediators of cell responses to tissue compression. Findings support the use of relatively simple isotropic modeling approaches for electrokinetic phenomena in cartilage and related materials, and indicate that measurement of electrokinetic properties may provide particularly robust means for clinical evaluation of cartilage matrix integrity.

  1. Imaging of articular cartilage: current concepts

    PubMed Central

    RONGA, MARIO; ANGERETTI, GLORIA; FERRARO, SERGIO; DE FALCO, GIOVANNI; GENOVESE, EUGENIO A.; CHERUBINO, PAOLO

    2014-01-01

    Magnetic resonance imaging (MRI) is the gold standard method for non-invasive assessment of joint cartilage, providing information on the structure, morphology and molecular composition of this tissue. There are certain minimum requirements for a MRI study of cartilage tissue: machines with a high magnetic field (> 1.5 Tesla); the use of surface coils; and the use of T2-weighted, proton density-weighted fast-spin echo (T2 FSE-DP) and 3D fat-suppressed T1-weighted gradient echo (3D-FS T1W GRE) sequences. For better contrast between the different joint structures, MR arthography is a method that can highlight minimal fibrillation or fractures of the articular surface and allow evaluation of the integrity of the native cartilage-repair tissue interface. To assess the biochemical composition of cartilage and cartilage repair tissue, various techniques have been proposed for studying proteoglycans [dGEMRIC, T1rho mapping, sodium (23Na) imaging MRI, etc.], collagen, and water distribution [T2 mapping, “magnetisation transfer contrast”, diffusion-weighted imaging (DWI), and so on]. Several MRI classifications have been proposed for evaluating the processes of joint degeneration (WORMS, BLOKS, ICRS) and post-surgical maturation of repair tissue (MOCART, 3D MOCART). In the future, isotropic 3D sequences set to improve image quality and facilitate the diagnosis of disorders of articular structures adjacent to cartilage. PMID:25606557

  2. Importance of material properties and porosity of bone on mechanical response of articular cartilage in human knee joint--a two-dimensional finite element study.

    PubMed

    Venäläinen, Mikko S; Mononen, Mika E; Jurvelin, Jukka S; Töyräs, Juha; Virén, Tuomas; Korhonen, Rami K

    2014-12-01

    Mechanical behavior of bone is determined by the structure and intrinsic, local material properties of the tissue. However, previously presented knee joint models for evaluation of stresses and strains in joints generally consider bones as rigid bodies or linearly elastic solid materials. The aim of this study was to estimate how different structural and mechanical properties of bone affect the mechanical response of articular cartilage within a knee joint. Based on a cadaver knee joint, a two-dimensional (2D) finite element (FE) model of a knee joint including bone, cartilage, and meniscus geometries was constructed. Six different computational models with varying properties for cortical, trabecular, and subchondral bone were created, while the biphasic fibril-reinforced properties of cartilage and menisci were kept unaltered. The simplest model included rigid bones, while the most complex model included specific mechanical properties for different bone structures and anatomically accurate trabecular structure. Models with different porosities of trabecular bone were also constructed. All models were exposed to axial loading of 1.9 times body weight within 0.2 s (mimicking typical maximum knee joint forces during gait) while free varus-valgus rotation was allowed and all other rotations and translations were fixed. As compared to results obtained with the rigid bone model, stresses, strains, and pore pressures observed in cartilage decreased depending on the implemented properties of trabecular bone. Greatest changes in these parameters (up to -51% in maximum principal stresses) were observed when the lowest modulus for trabecular bone (measured at the structural level) was used. By increasing the trabecular bone porosity, stresses and strains were reduced substantially in the lateral tibial cartilage, while they remained relatively constant in the medial tibial plateau. The present results highlight the importance of long bones, in particular, their mechanical

  3. SPOC1 modulates DNA repair by regulating key determinants of chromatin compaction and DNA damage response

    PubMed Central

    Mund, Andreas; Schubert, Tobias; Staege, Hannah; Kinkley, Sarah; Reumann, Kerstin; Kriegs, Malte; Fritsch, Lauriane; Battisti, Valentine; Ait-Si-Ali, Slimane; Hoffbeck, Anne-Sophie; Soutoglou, Evi; Will, Hans

    2012-01-01

    Survival time-associated plant homeodomain (PHD) finger protein in Ovarian Cancer 1 (SPOC1, also known as PHF13) is known to modulate chromatin structure and is essential for testicular stem-cell differentiation. Here we show that SPOC1 is recruited to DNA double-strand breaks (DSBs) in an ATM-dependent manner. Moreover, SPOC1 localizes at endogenous repair foci, including OPT domains and accumulates at large DSB repair foci characteristic for delayed repair at heterochromatic sites. SPOC1 depletion enhances the kinetics of ionizing radiation-induced foci (IRIF) formation after γ-irradiation (γ-IR), non-homologous end-joining (NHEJ) repair activity, and cellular radioresistance, but impairs homologous recombination (HR) repair. Conversely, SPOC1 overexpression delays IRIF formation and γH2AX expansion, reduces NHEJ repair activity and enhances cellular radiosensitivity. SPOC1 mediates dose-dependent changes in chromatin association of DNA compaction factors KAP-1, HP1-α and H3K9 methyltransferases (KMT) GLP, G9A and SETDB1. In addition, SPOC1 interacts with KAP-1 and H3K9 KMTs, inhibits KAP-1 phosphorylation and enhances H3K9 trimethylation. These findings provide the first evidence for a function of SPOC1 in DNA damage response (DDR) and repair. SPOC1 acts as a modulator of repair kinetics and choice of pathways. This involves its dose-dependent effects on DNA damage sensors, repair mediators and key regulators of chromatin structure. PMID:23034801

  4. Familiality of mood repair responses among youth with and without histories of depression.

    PubMed

    Bylsma, Lauren M; Yaroslavsky, Ilya; Rottenberg, Jonathan; Kiss, Enikő; Kapornai, Krisztina; Halas, Kitti; Dochnal, Roberta; Lefkovics, Eszter; Baji, Ildikό; Vetrό, Ágnes; Kovacs, Maria

    2016-01-01

    Affect regulation skills develop in the context of the family environment, wherein youths are influenced by their parents', and possibly their siblings', regulatory responses and styles. Regulatory responses to sadness (mood repair) that exacerbate or prolong dysphoria (maladaptive mood repair) may represent one way in which depression is transmitted within families. We examined self-reported adaptive and maladaptive mood repair responses across cognitive, social and behavioural domains in Hungarian 11- to 19-year-old youth and their parents. Offspring included 214 probands with a history of childhood-onset depressive disorder, 200 never depressed siblings and 161 control peers. Probands reported the most problematic mood repair responses, with siblings reporting more modest differences from controls. Mood repair responses of parents and their offspring, as well as within sib-pairs, were related, although results differed as a function of the regulatory response domain. Results demonstrate familiality of maladaptive and adaptive mood repair responses in multiple samples. These familial associations suggest that relationships with parents and siblings within families may impact the development of affect regulation in youth. PMID:25849259

  5. Induction of inflammatory cytokines by cartilage extracts.

    PubMed

    Merly, Liza; Simjee, Shabana; Smith, Sylvia L

    2007-03-01

    Shark cartilage extracts were examined for induction of cytokines and chemokines in human peripheral blood leukocytes. Primary leukocyte cultures were exposed to a variety of aqueous and organic extracts prepared from several commercial brands of shark cartilage. From all commercial sources of shark cartilage tested the acid extracts induced higher levels of TNFalpha than other extracts. Different commercial brands of shark cartilage varied significantly in cytokine-inducing activity. TNFalpha induction was seen as early as 4 h and IFNgamma at detectable levels for up to four days. Shark cartilage extracts did not induce physiologically significant levels of IL-4. Results suggest that shark cartilage, preferentially, induces Th1 type inflammatory cytokines. When compared to bovine cartilage extract, collagen, and chondroitin sulfate, shark cartilage induced significantly higher levels of TNFalpha. Treatment with digestive proteases (trypsin and chymotrypsin) reduced the cytokine induction response by 80%, suggesting that the active component(s) in cartilage extracts is proteinaceous. The induction of Th1 type cytokine response in leukocytes is a significant finding since shark cartilage, taken as a dietary supplement for a variety of chronic degenerative diseases, would be contraindicated in cases where the underlying pathology of the chronic condition is caused by inflammation. PMID:17276897

  6. From gristle to chondrocyte transplantation: treatment of cartilage injuries

    PubMed Central

    Lindahl, Anders

    2015-01-01

    This review addresses the progress in cartilage repair technology over the decades with an emphasis on cartilage regeneration with cell therapy. The most abundant cartilage is the hyaline cartilage that covers the surface of our joints and, due to avascularity, this tissue is unable to repair itself. The cartilage degeneration seen in osteoarthritis causes patient suffering and is a huge burden to society. The surgical approach to cartilage repair was non-existing until the 1950s when new surgical techniques emerged. The use of cultured cells for cell therapy started as experimental studies in the 1970s that developed over the years to a clinical application in 1994 with the introduction of the autologous chondrocyte transplantation technique (ACT). The technology is now spread worldwide and has been further refined by combining arthroscopic techniques with cells cultured on matrix (MACI technology). The non-regenerating hypothesis of cartilage has been revisited and we are now able to demonstrate cell divisions and presence of stem-cell niches in the joint. Furthermore, cartilage derived from human embryonic stem cells and induced pluripotent stem cells could be the base for new broader cell treatments for cartilage injuries and the future technology base for prevention and cure of osteoarthritis. PMID:26416680

  7. Cartilage issues in football-today's problems and tomorrow's solutions.

    PubMed

    Mithoefer, Kai; Peterson, Lars; Zenobi-Wong, Marcy; Mandelbaum, Bert R

    2015-05-01

    Articular cartilage injury is prevalent in football players and results from chronic joint stress or acute traumatic injuries. Articular cartilage injury can often result in progressive painful impairment of joint function and limit sports participation. Management of articular cartilage injury in athletes aims to return the player to competition, and requires effective and durable joint surface restoration that resembles normal hyaline articular cartilage that can withstand the high joint stresses of football. Existing articular cartilage repair techniques can return the athlete with articular cartilage injury to high-impact sports, but treatment does not produce normal articular cartilage, and this limits the success rate and durability of current cartilage repair in athletes. Novel scientific concepts and treatment techniques that apply modern tissue engineering technologies promise further advancement in the treatment of these challenging injuries in the high demand athletic population. We review the current knowledge of cartilage injury pathophysiology, epidemiology and aetiology, and outline existing management algorithms, developing treatment options and future strategies to manage articular cartilage injuries in football players. PMID:25878075

  8. Cartilage issues in football—today's problems and tomorrow's solutions

    PubMed Central

    Mithoefer, Kai; Peterson, Lars; Zenobi-Wong, Marcy; Mandelbaum, Bert R

    2015-01-01

    Articular cartilage injury is prevalent in football players and results from chronic joint stress or acute traumatic injuries. Articular cartilage injury can often result in progressive painful impairment of joint function and limit sports participation. Management of articular cartilage injury in athletes aims to return the player to competition, and requires effective and durable joint surface restoration that resembles normal hyaline articular cartilage that can withstand the high joint stresses of football. Existing articular cartilage repair techniques can return the athlete with articular cartilage injury to high-impact sports, but treatment does not produce normal articular cartilage, and this limits the success rate and durability of current cartilage repair in athletes. Novel scientific concepts and treatment techniques that apply modern tissue engineering technologies promise further advancement in the treatment of these challenging injuries in the high demand athletic population. We review the current knowledge of cartilage injury pathophysiology, epidemiology and aetiology, and outline existing management algorithms, developing treatment options and future strategies to manage articular cartilage injuries in football players. PMID:25878075

  9. An equine joint friction test model using a cartilage-on-cartilage arrangement.

    PubMed

    Noble, Prisca; Collin, Bernard; Lecomte-Beckers, Jacqueline; Magnée, Adrien; Denoix, Jean M; Serteyn, Didier

    2010-02-01

    This study describes an equine joint friction test using a cartilage-on-cartilage arrangement and investigates the influence of age and load on the frictional response. Osteochondral plugs were extracted from equine shoulder joints (2-5 years, n=12; 10-14 years, n=15), and mounted in a pin-on-disc tribometer. The frictional response was then measured under constant conditions (2N; 20 degrees C; 5 mm/s), and with increasing load (2N, 5N, 10N). In all experiments, the friction coefficient of young cartilage was significantly (P<0.001) smaller than obtained from old cartilage, while the application of a greater load resulted in a significant (P<0.001) decrease in friction coefficient only in old cartilage. It was concluded that cartilage ageing was responsible for an increase in friction coefficient under these experimental conditions. Moreover, where young cartilage lubrication remained stable, cartilage ageing may have been responsible for lubrication regime change. The cartilage-on-cartilage model could be used to better understand lubrication regime disturbances in healthy and diseased equine joints, and to test the efficacy of various bio-lubricant treatments.

  10. A Two-tiered compensatory response to loss of DNA repair modulates aging and stress response pathways

    PubMed Central

    Fensgård, Øyvind; Kassahun, Henok; Bombik, Izabela; Rognes, Torbjørn; Lindvall, Jessica Margareta; Nilsen, Hilde

    2010-01-01

    Activation of oxidative stress-responses and downregulation of insulin-like signaling (ILS) is seen in Nucleotide Excision Repair (NER) deficient segmental progeroid mice. Evidence suggests that this is a survival response to persistent transcription-blocking DNA damage, although the relevant lesions have not been identified. Here we show that loss of NTH-1, the only Base Excision Repair (BER) enzyme known to initiate repair of oxidative DNA damage inC. elegans, restores normal lifespan of the short-lived NER deficient xpa-1 mutant. Loss of NTH-1 leads to oxidative stress and global expression profile changes that involve upregulation of genes responding to endogenous stress and downregulation of ILS. A similar, but more extensive, transcriptomic shift is observed in the xpa-1 mutant whereas loss of both NTH-1 and XPA-1 elicits a different profile with downregulation of Aurora-B and Polo-like kinase 1 signaling networks as well as DNA repair and DNA damage response genes. The restoration of normal lifespan and absence oxidative stress responses in nth-1;xpa-1 indicate that BER contributes to generate transcription blocking lesions from oxidative DNA damage. Hence, our data strongly suggests that the DNA lesions relevant for aging are repair intermediates resulting from aberrant or attempted processing by BER of lesions normally repaired by NER. PMID:20382984

  11. Tissue repair after condylectomy in growing Macaca fascicularis.

    PubMed

    Bakker, V M; Swartberg, P E; Heeley, J D

    1984-02-01

    In order to determine the nature of tissue repair after removal of condyles, bilateral condylectomies were performed in seven growing female Macaca fascicularis. Two animals underwent condylectomies only, and five animals were fitted with maxillary and mandibular splints before undergoing condylectomies. One condyle from each condylectomized animal was processed for histologic examination. Four animals, with intact condyles, were available as controls: Two had splints placed, while the other two did not undergo any treatment. Nine mo after surgery, the histology of 12 resection sites and 12 control condyles (seven removed at condylectomy and five at death) was compared. In the control condyles, hypertrophic cartilage was seen over the entire condylar surface. From the 12 resection sites, five showed hypertrophic cartilage, non-hypertrophic cartilage cells were present in three, and four demonstrated bone apposition and resorption. Cartilage was present only at the medial and central aspects of the surgical site, and in every specimen, bone was seen at the lateral pole. Two out of 12 fossae overlying surgical sites contained hypertrophic cartilage, while the five control glenoid fossae showed bone, an intermediate zone, and a fibrous capsule. Because of the variety in tissue response and the small number of animals in each group, the effect of the splints could not be determined. Based on the results of this study, the following was concluded: (1) Regeneration of organized hypertrophic cartilage with inherent growth potential can take place after condylectomy, albeit not in every instance and only in the medial aspect of the stump. In the lateral aspect, and also medially if hypertrophic cartilage does not reform, bone is predominant. The original height is not recovered. (2) The cartilage of the glenoid fossa is capable of adaptive changes similar to those seen in condylar cartilage. PMID:6582091

  12. Cartilage tissue engineering: recent advances and perspectives from gene regulation/therapy.

    PubMed

    Li, Kuei-Chang; Hu, Yu-Chen

    2015-05-01

    Diseases in articular cartilages affect millions of people. Despite the relatively simple biochemical and cellular composition of articular cartilages, the self-repair ability of cartilage is limited. Successful cartilage tissue engineering requires intricately coordinated interactions between matrerials, cells, biological factors, and phycial/mechanical factors, and still faces a multitude of challenges. This article presents an overview of the cartilage biology, current treatments, recent advances in the materials, biological factors, and cells used in cartilage tissue engineering/regeneration, with strong emphasis on the perspectives of gene regulation (e.g., microRNA) and gene therapy.

  13. Antibiotic persistence: the role of spontaneous DNA repair response.

    PubMed

    Debbia, E A; Roveta, S; Schito, A M; Gualco, L; Marchese, A

    2001-01-01

    Persisters are a small proportion of a bacterial population that exists in a physiological state permitting survival despite the lethal activity of antibiotics. To explain this phenomenon, it has been suggested that persisters are bacteria repairing spontaneous errors of DNA synthesis. To verify this assumption, Escherichia coli AB1157 and its lexA3 derivative were exposed to a dose 6x MIC of various antibiotics representative of different molecular mechanisms of action (ampicillin, ceftriaxone, meropenem, amikacin, ciprofloxacin). Bacterial cell counts, after 24 hr of exposure to the antimicrobials, revealed a reduction of about 90% of viable organisms in the lexA3 strains in comparison to the lexA+. In several cases, the number of colony-forming units decreased below the limit of assay. This behavior was noted with all antibiotics used, alone or in combination (amikacin plus ceftriaxone and amikacin plus ciprofloxacin). The same experiments were repeated using E. coli AB1157 cultured in the presence of mitomycin C (0.25x MIC), and the number of survivors exceeded by about 90% the values found in the nonexposed control. In contrast, in the sulA background, mitomycin C reacted synergically with all the antibiotics tested causing a strong reduction of the survivors in comparison with the control. The addition of chloramphenicol (0.125x MIC), on the contrary, caused a reduction of the number of survivors of about 90%. These findings indicate that, when DNA repair is active (a mechanism known to block cell division), the number of survivors is greater than that observed with lexA3. Thus, in addition to other possible explanations, persisters might be a fraction of bacteria that during antibiotic treatment are not growing because they are repairing spontaneous errors of DNA synthesis.

  14. Effect of highly purified capsaicin on articular cartilage and rotator cuff tendon healing: An in vivo rabbit study.

    PubMed

    Friel, Nicole A; McNickle, Allison G; DeFranco, Michael J; Wang, FanChia; Shewman, Elizabeth F; Verma, Nikhil N; Cole, Brian J; Bach, Bernard R; Chubinskaya, Susan; Kramer, Susan M; Wang, Vincent M

    2015-12-01

    Highly purified capsaicin has emerged as a promising injectable compound capable of providing sustained pain relief following a single localized treatment during orthopedic surgical procedures. To further assess its reliability for clinical use, the potential effect of highly purified capsaicin on articular cartilage metabolism as well as tendon structure and function warrants clarification. In the current study, rabbits received unilateral supraspinatus transection and repair with a single 1 ml injection of capsaicin (R+C), PEG-only placebo (R+P), or saline (R+S) into the glenohumeral joint (GHJ). An additional group received 1 ml capsaicin onto an intact rotator cuff (I+C). At 18 weeks post-op, cartilage proteoglycan (PG) synthesis and content as well as cell viability were similar (p>0.05) across treatment groups. Biomechanical testing revealed no differences (p>0.05) among tendon repair treatment groups. Similarly, histologic features of both cartilage and repaired tendons showed minimal differences across groups. Hence, in this rabbit model, a single injection of highly purified capsaicin into the GHJ does not induce a deleterious response with regard to cartilage matrix metabolism and cell viability, or rotator cuff healing. These data provide further evidence supporting the use of injectable, highly purified capsaicin as a safe alternative for management of postoperative pain following GHJ surgery. PMID:26135547

  15. Effect of highly purified capsaicin on articular cartilage and rotator cuff tendon healing: An in vivo rabbit study.

    PubMed

    Friel, Nicole A; McNickle, Allison G; DeFranco, Michael J; Wang, FanChia; Shewman, Elizabeth F; Verma, Nikhil N; Cole, Brian J; Bach, Bernard R; Chubinskaya, Susan; Kramer, Susan M; Wang, Vincent M

    2015-12-01

    Highly purified capsaicin has emerged as a promising injectable compound capable of providing sustained pain relief following a single localized treatment during orthopedic surgical procedures. To further assess its reliability for clinical use, the potential effect of highly purified capsaicin on articular cartilage metabolism as well as tendon structure and function warrants clarification. In the current study, rabbits received unilateral supraspinatus transection and repair with a single 1 ml injection of capsaicin (R+C), PEG-only placebo (R+P), or saline (R+S) into the glenohumeral joint (GHJ). An additional group received 1 ml capsaicin onto an intact rotator cuff (I+C). At 18 weeks post-op, cartilage proteoglycan (PG) synthesis and content as well as cell viability were similar (p>0.05) across treatment groups. Biomechanical testing revealed no differences (p>0.05) among tendon repair treatment groups. Similarly, histologic features of both cartilage and repaired tendons showed minimal differences across groups. Hence, in this rabbit model, a single injection of highly purified capsaicin into the GHJ does not induce a deleterious response with regard to cartilage matrix metabolism and cell viability, or rotator cuff healing. These data provide further evidence supporting the use of injectable, highly purified capsaicin as a safe alternative for management of postoperative pain following GHJ surgery.

  16. Synthesis and extracellular deposition of fibronectin in chondrocyte cultures. Response to the removal of extracellular cartilage matrix

    PubMed Central

    1978-01-01

    Fibronectin, the major cell surface glycoprotein of fibroblasts, is absent from differentiated cartilage matrix and chondrocytes in situ. However, dissociation of embryonic chick sternal cartilage with collagenase and trypsin, followed by inoculation in vitro reinitiates fibronectin synthesis by chondrocytes. Immunofluorescence microscopy with antibodies prepared against plasma fibronectin (cold insoluble globulin [CIG]) reveals fibronectin associated with the chondrocyte surface. Synthesis and secretion of fibronectin into the medium are shown by anabolic labeling with [35S]methionine or [3H]glycine, and identification of the secreted proteins by immunoprecipitation and sodium dodecyl sulfate (SDS)-disc gel electrophoresis. When chondrocytes are plated onto tissue culture dishes, the pattern of surface-associated fibronectin changes from a patchy into a strandlike appearance. Where epithelioid clones of polygonal chondrocytes develop, only short strands of fibronectin appear preferentially at cellular interfaces. This pattern is observed as long as cells continue to produce type II collagen that fails to precipitate as extracellular collagen fibers for some time in culture. Using the immunofluorescence double-labeling technique, we demonstrate that fibroblasts as well as chondrocytes which synthesize type I collagen and deposit this collagen as extracellular fibers show a different pattern of extracellular fibronectin that codistributes in large parts with collagen fibers. Where chondrocytes begin to accumulate extracellular cartilage matrix, fibronectin strands disappear. From these observations, we conclude (a) that chondrocytes synthesize fibronectin only in the absence of extracellular cartilage matrix, and (b) that fibronectin forms only short intercellular "stitches" in the absence of extracellular collagen fibers in vitro. PMID:363726

  17. Cardiorespiratory responses to exercise after anatomic repair of atrioventricular discordance with abnormal ventriculoarterial connection.

    PubMed

    Yasuda, Kenji; Ohuchi, Hideo; Ono, Yasuo; Yagihara, Toshikatsu; Echigo, Shigeyuki

    2007-01-01

    We evaluated exercise tolerance and cardiorespiratory responses to exercise in patients with atrioventricular discordance (AVD) and abnormal ventriculoarterial connection after anatomic repair. Cardiopulmonary treadmill exercise testing with gas measurement was done 62 times in 19 patients with AVD who had undergone anatomic repair at the National Cardiovascular Center. Exercise duration, oxygen uptake (V(O2)) and heart rate at anaerobic threshold and peak, and oxygen pulse during exercise were significantly lower in patients with AVD after anatomic repair than in controls. Carbon dioxide ventilatory equivalent during exercise was worse in patients with AVD after anatomic repair than in controls. Percentage peak V(O2) significantly correlated positively with percentage peak oxygen pulse and tended to correlate positively with the heart rate increments. Patients with AVD after anatomic repair exhibit impaired responses of heart rate and oxygen pulse with lower exercise capacity. Careful attention should be paid to patients with AVD after anatomic repair in terms of their functional capacity as well as other postoperative complications.

  18. Stem Cell-assisted Approaches for Cartilage Tissue Engineering.

    PubMed

    Park, In-Kyu; Cho, Chong-Su

    2010-05-01

    The regeneration of damaged articular cartilage remains challenging due to its poor intrinsic capacity for repair. Tissue engineering of articular cartilage is believed to overcome the current limitations of surgical treatment by offering functional regeneration in the defect region. Selection of proper cell sources and ECM-based scaffolds, and incorporation of growth factors or mechanical stimuli are of primary importance to successfully produce artificial cartilage for tissue repair. When designing materials for cartilage tissue engineering, biodegradability and biocompatibility are the key factors in selecting material candidates, for either synthetic or natural polymers. The unique environment of cartilage makes it suitable to use a hydrogel with high water content in the cross-linked or thermosensitive (injectable) form. Moreover, design of composite scaffolds from two polymers with complementary physicochemical and biological properties has been explored to provide residing chondrocytes with a combination of the merits that each component contributes.

  19. Articular Cartilage Changes in Maturing Athletes

    PubMed Central

    Luria, Ayala; Chu, Constance R.

    2014-01-01

    Context: Articular cartilage has a unique functional architecture capable of providing a lifetime of pain-free joint motion. This tissue, however, undergoes substantial age-related physiologic, mechanical, biochemical, and functional changes that reduce its ability to overcome the effects of mechanical stress and injury. Many factors affect joint function in the maturing athlete—from chondrocyte survival and metabolism to structural composition and genetic/epigenetic factors governing cartilage and synovium. An evaluation of age-related changes for joint homeostasis and risk for osteoarthritis is important to the development of new strategies to rejuvenate aging joints. Objective: This review summarizes the current literature on the biochemical, cellular, and physiologic changes occurring in aging articular cartilage. Data Sources: PubMed (1969-2013) and published books in sports health, cartilage biology, and aging. Study Selection: Keywords included aging, athlete, articular cartilage, epigenetics, and functional performance with age. Study Design: Systematic review. Level of Evidence: Level 3. Data Extraction: To be included, research questions addressed the effect of age-related changes on performance, articular cartilage biology, molecular mechanism, and morphology. Results: The mature athlete faces challenges in maintaining cartilage health and joint function due to age-related changes to articular cartilage biology, morphology, and physiology. These changes include chondrocyte loss and a decline in metabolic response, alterations to matrix and synovial tissue composition, and dysregulation of reparative responses. Conclusion: Although physical decline has been regarded as a normal part of aging, many individuals maintain overall fitness and enjoy targeted improvement to their athletic capacity throughout life. Healthy articular cartilage and joints are needed to maintain athletic performance and general activities. Genetic and potentially reversible

  20. Drug-eluting scaffolds for bone and cartilage regeneration.

    PubMed

    Huang, Charlotte L; Lee, Wei Li; Loo, Joachim S C

    2014-06-01

    The advances in strategies for bone and cartilage regeneration have been centered on a concept that describes the close relationship between osteogenic cells, osteoconductive scaffolds, delivery growth factors and the mechanical environment. The dynamic nature of the tissue repair process involves intricate mimicry of signals expressed in the biological system in response to an injury. Recently, synergistic strategies involving hybrid delivery systems that provide sequential dual delivery of biomolecules and relevant topological cues received great attention. Future advances in tissue regeneration will therefore depend on multidisciplinary strategies that encompass the crux of tissue repair aimed at constructing the ideal functional regenerative scaffold. Here, functional scaffolds delivering therapeutics are reviewed in terms of their controlled release and healing capabilities. PMID:24239726

  1. Helicobacter pylori Disrupts Host Cell Membranes, Initiating a Repair Response and Cell Proliferation

    PubMed Central

    Lin, Li-Ling; Huang, Hsuan-Cheng; Ogihara, Satoshi; Wang, Jin-Town; Wu, Meng-Chuan; McNeil, Paul L.; Chen, Chiung-Nien; Juan, Hsueh-Fen

    2012-01-01

    Helicobacter pylori (H. pylori), the human stomach pathogen, lives on the inner surface of the stomach and causes chronic gastritis, peptic ulcer, and gastric cancer. Plasma membrane repair response is a matter of life and death for human cells against physical and biological damage. We here test the hypothesis that H. pylori also causes plasma membrane disruption injury, and that not only a membrane repair response but also a cell proliferation response are thereby activated. Vacuolating cytotoxin A (VacA) and cytotoxin-associated gene A (CagA) have been considered to be major H. pylori virulence factors. Gastric cancer cells were infected with H. pylori wild type (vacA+/cagA+), single mutant (ΔvacA or ΔcagA) or double mutant (ΔvacA/ΔcagA) strains and plasma membrane disruption events and consequent activation of membrane repair components monitored. H. pylori disrupts the host cell plasma membrane, allowing localized dye and extracellular Ca2+ influx. Ca2+-triggered members of the annexin family, A1 and A4, translocate, in response to injury, to the plasma membrane, and cell surface expression of an exocytotic maker of repair, LAMP-2, increases. Additional forms of plasma membrane disruption, unrelated to H. pylori exposure, also promote host cell proliferation. We propose that H. pylori activation of a plasma membrane repair is pro-proliferative. This study might therefore provide new insight into potential mechanisms of H. pylori-induced gastric carcinogenesis. PMID:22949854

  2. Clinical translation of stem cells: insight for cartilage therapies

    PubMed Central

    Lee, Jennifer K.; Responte, Donald J.; Cissell, Derek D.; Hu, Jerry C.; Nolta, Jan A.; Athanasiou, Kyriacos A.

    2015-01-01

    The limited regenerative capacity of articular cartilage and deficiencies of current treatments have motivated the investigation of new repair technologies. In vitro cartilage generation using primary cell sources is limited by cell availability and expansion potential. Pluripotent stem cells possess the capacity for chondrocytic differentiation and extended expansion, providing a potential future solution to cell-based cartilage regeneration. However, despite successes in producing cartilage using adult and embryonic stem cells, the translation of these technologies to the clinic has been severely limited. This review discusses recent advances in stem cell-based cartilage tissue engineering and the major current limitations to clinical translation of these products. Concerns regarding appropriate animal models and studies, stem cell manufacturing, and relevant regulatory processes and guidelines will be addressed. Understanding the significant hurdles limiting the clinical use of stem cell-based cartilage may guide future developments in the fields of tissue engineering and regenerative medicine. PMID:24083452

  3. Human Pluripotent Stem Cells Have a Novel Mismatch Repair-dependent Damage Response*

    PubMed Central

    Lin, Bo; Gupta, Dipika; Heinen, Christopher D.

    2014-01-01

    Human pluripotent stem cells (PSCs) are presumed to have robust DNA repair pathways to ensure genome stability. PSCs likely need to protect against mutations that would otherwise be propagated throughout all tissues of the developing embryo. How these cells respond to genotoxic stress has only recently begun to be investigated. Although PSCs appear to respond to certain forms of damage more efficiently than somatic cells, some DNA damage response pathways such as the replication stress response may be lacking. Not all DNA repair pathways, including the DNA mismatch repair (MMR) pathway, have been well characterized in PSCs to date. MMR maintains genomic stability by repairing DNA polymerase errors. MMR is also involved in the induction of cell cycle arrest and apoptosis in response to certain exogenous DNA-damaging agents. Here, we examined MMR function in PSCs. We have demonstrated that PSCs contain a robust MMR pathway and are highly sensitive to DNA alkylation damage in an MMR-dependent manner. Interestingly, the nature of this alkylation response differs from that previously reported in somatic cell types. In somatic cells, a permanent G2/M cell cycle arrest is induced in the second cell cycle after DNA damage. The PSCs, however, directly undergo apoptosis in the first cell cycle. This response reveals that PSCs rely on apoptotic cell death as an important defense to avoid mutation accumulation. Our results also suggest an alternative molecular mechanism by which the MMR pathway can induce a response to DNA damage that may have implications for tumorigenesis. PMID:25012654

  4. [Tribological assessment of articular cartilage. A system for the analysis of the friction coefficient of cartilage, regenerates and tissue engineering constructs; initial results].

    PubMed

    Schwarz, M L R; Schneider-Wald, B; Krase, A; Richter, W; Reisig, G; Kreinest, M; Heute, S; Pott, P P; Brade, J; Schütte, A

    2012-10-01

    Values for the friction coefficient of articular cartilage are given in ranges of percentage and lower and are calculated as a quotient of the friction force and the perpendicular loading force acting on it. Thus, a sophisticated system has to be provided for analysing the friction coefficient under different conditions in particular when cartilage should be coupled as friction partner. It is possible to deep-freeze articular cartilage before measuring the friction coefficient as the procedure has no influence on the results. The presented tribological system was able to distinguish between altered and native cartilage. Furthermore, tissue engineered constructs for cartilage repair were differentiated from native cartilage probes by their friction coefficient. In conclusion a tribological equipment is presented to analyze the friction coefficient of articular cartilage, in vivo generated cartilage regenerates and in vitro tissue engineered constructs regarding their biomechanical properties for quality assessment.

  5. Equine cricoid cartilage densitometry.

    PubMed Central

    Behrens, E; Poteet, B; Cohen, N

    1993-01-01

    The density of the cricoid cartilage from 29 equine larynges collected from an abattoir was determined by dual photon absorptiometry (DPA). Densities of the right and left cricoid cartilages were highly correlated. No correlation was found between age of the horse and the density of the cricoid cartilage. PMID:8269372

  6. In vitro growth factor-induced bio engineering of mature articular cartilage

    PubMed Central

    Khan, Ilyas M.; Francis, Lewis; Theobald, Peter S.; Perni, Stefano; Young, Robert D.; Prokopovich, Polina; Conlan, R. Steven; Archer, Charles W.

    2013-01-01

    Articular cartilage maturation is the postnatal development process that adapts joint surfaces to their site-specific biomechanical demands. Maturation involves gross morphological changes that occur through a process of synchronised growth and resorption of cartilage and generally ends at sexual maturity. The inability to induce maturation in biomaterial constructs designed for cartilage repair has been cited as a major cause for their failure in producing persistent cell-based repair of joint lesions. The combination of growth factors FGF2 and TGFβ1 induces accelerated articular cartilage maturation in vitro such that many molecular and morphological characteristics of tissue maturation are observable. We hypothesised that experimental growth factor-induced maturation of immature cartilage would result in a biophysical and biochemical composition consistent with a mature phenotype. Using native immature and mature cartilage as reference, we observed that growth factor-treated immature cartilages displayed increased nano-compressive stiffness, decreased surface adhesion, decreased water content, increased collagen content and smoother surfaces, correlating with a convergence to the mature cartilage phenotype. Furthermore, increased gene expression of surface structural protein collagen type I in growth factor-treated explants compared to reference cartilages demonstrates that they are still in the dynamic phase of the postnatal developmental transition. These data provide a basis for understanding the regulation of postnatal maturation of articular cartilage and the application of growth factor-induced maturation in vitro and in vivo in order to repair and regenerate cartilage defects. PMID:23182922

  7. Progression of Gene Expression Changes following a Mechanical Injury to Articular Cartilage as a Model of Early Stage Osteoarthritis

    PubMed Central

    McCulloch, R. S.; Ashwell, M. S.; Maltecca, C.; O'Nan, A. T.; Mente, P. L.

    2014-01-01

    An impact injury model of early stage osteoarthritis (OA) progression was developed using a mechanical insult to an articular cartilage surface to evaluate differential gene expression changes over time and treatment. Porcine patellae with intact cartilage surfaces were randomized to one of three treatments: nonimpacted control, axial impaction (2000 N), or a shear impaction (500 N axial, with tangential displacement to induce shear forces). After impact, the patellae were returned to culture for 0, 3, 7, or 14 days. At the appropriate time point, RNA was extracted from full-thickness cartilage slices at the impact site. Quantitative real-time PCR was used to evaluate differential gene expression for 18 OA related genes from four categories: cartilage matrix, degradative enzymes and inhibitors, inflammatory response and signaling, and cell apoptosis. The shear impacted specimens were compared to the axial impacted specimens and showed that shear specimens more highly expressed type I collagen (Col1a1) at the early time points. In addition, there was generally elevated expression of degradative enzymes, inflammatory response genes, and apoptosis markers at the early time points. These changes suggest that the more physiologically relevant shear loading may initially be more damaging to the cartilage and induces more repair efforts after loading. PMID:25478225

  8. An In Vitro Comparison of the Incorporation, Growth, and Chondrogenic Potential of Human Bone Marrow versus Adipose Tissue Mesenchymal Stem Cells in Clinically Relevant Cell Scaffolds Used for Cartilage Repair

    PubMed Central

    Kohli, Nupur; Wright, Karina T.; Sammons, Rachel L.; Jeys, Lee; Snow, Martyn

    2015-01-01

    Aim To compare the incorporation, growth, and chondrogenic potential of bone marrow (BM) and adipose tissue (AT) mesenchymal stem cells (MSCs) in scaffolds used for cartilage repair. Methods Human BM and AT MSCs were isolated, culture expanded, and characterised using standard protocols, then seeded into 2 different scaffolds, Chondro-Gide or Alpha Chondro Shield. Cell adhesion, incorporation, and viable cell growth were assessed microscopically and following calcein AM/ethidium homodimer (Live/Dead) staining. Cell-seeded scaffolds were treated with chondrogenic inducers for 28 days. Extracellular matrix deposition and soluble glycosaminoglycan (GAG) release into the culture medium was measured at day 28 by histology/immunohistochemistry and dimethylmethylene blue assay, respectively. Results A greater number of viable MSCs from either source adhered and incorporated into Chondro-Gide than into Alpha Chondro Shield. In both cell scaffolds, this incorporation represented less than 2% of the cells that were seeded. There was a marked proliferation of BM MSCs, but not AT MSCs, in Chondro-Gide. MSCs from both sources underwent chondrogenic differentiation following induction. However, cartilaginous extracellular matrix deposition was most marked in Chondro-Gide seeded with BM MSCs. Soluble GAG secretion increased in chondrogenic versus control conditions. There was no marked difference in GAG secretion by MSCs from either cell source. Conclusion Chondro-Gide and Alpha Chondro Shield were permissive to the incorporation and chondrogenic differentiation of human BM and AT MSCs. Chondro-Gide seeded with BM MSCs demonstrated the greatest increase in MSC number and deposition of a cartilaginous tissue. PMID:26425263

  9. Innate and adaptive immune responses in neurodegeneration and repair.

    PubMed

    Amor, Sandra; Woodroofe, M Nicola

    2014-03-01

    Emerging evidence suggests important roles of the innate and adaptive immune responses in the central nervous system (CNS) in neurodegenerative diseases. In this special review issue, five leading researchers discuss the evidence for the beneficial as well as the detrimental impact of the immune system in the CNS in disorders including Alzheimer's disease, multiple sclerosis and CNS injury. Several common pathological mechanisms emerge indicating that these pathways could provide important targets for manipulating the immune reposes in neurodegenerative disorders. The articles highlight the role of the traditional resident immune cell of the CNS - the microglia - as well as the role of other glia astrocytes and oligodendrocytes in immune responses and their interplay with other immune cells including, mast cells, T cells and B cells. Future research should lead to new discoveries which highlight targets for therapeutic interventions which may be applicable to a range of neurodegenerative diseases.

  10. The Application of Sheet Technology in Cartilage Tissue Engineering.

    PubMed

    Ge, Yang; Gong, Yi Yi; Xu, Zhiwei; Lu, Yanan; Fu, Wei

    2016-04-01

    Cartilage tissue engineering started to act as a promising, even essential alternative method in the process of cartilage repair and regeneration, considering adult avascular structure has very limited self-renewal capacity of cartilage tissue in adults and a bottle-neck existed in conventional surgical treatment methods. Recent progressions in tissue engineering realized the development of more feasible strategies to treat cartilage disorders. Of these strategies, cell sheet technology has shown great clinical potentials in the regenerative areas such as cornea and esophagus and is increasingly considered as a potential way to reconstruct cartilage tissues for its non-use of scaffolds and no destruction of matrix secreted by cultured cells. Acellular matrix sheet technologies utilized in cartilage tissue engineering, with a sandwich model, can ingeniously overcome the drawbacks that occurred in a conventional acellular block, where cells are often blocked from migrating because of the non-nanoporous structure. Electrospun-based sheets with nanostructures that mimic the natural cartilage matrix offer a level of control as well as manipulation and make them appealing and widely used in cartilage tissue engineering. In this review, we focus on the utilization of these novel and promising sheet technologies to construct cartilage tissues with practical and beneficial functions. PMID:26414455

  11. Evaluation of apparent fracture toughness of articular cartilage and hydrogels

    PubMed Central

    Xiao, Yinghua; Rennerfeldt, Deena A.; Friis, Elizabeth A.; Gehrke, Stevin H.; Detamore, Michael S.

    2014-01-01

    Recently, biomaterials-based tissue-engineering strategies, including the use of hydrogels, have offered great promise for repairing articular cartilage. Mechanical failure testing in outcome analyses is of crucial clinical importance to the success of engineered constructs. Interpenetrating networks (IPNs) are gaining more attention, due to their superior mechanical integrity. This study provided a combination testing method of apparent fracture toughness, which was applied to both articular cartilage and hydrogels. The apparent fracture toughnesses of two groups, hydrogels and articular cartilage, were evaluated based on the modified single-edge notch test and ASTM standards on the single-edge notch test and compact tension test. The results demonstrated that the toughness for articular cartilage (348 ± 43 MPa/mm½) was much higher than that for hydrogels. With a toughness value of 10.8 ± 1.4 MPa/mm½, IPNs of agarose and poly(ethylene glycol) diacrylate (PEG-DA) looked promising. The IPNs were 1.4 times tougher than PEG-DA alone, although still over an order of magnitude less tough than cartilage. A new method was developed to evaluate hydrogels and cartilage in a manner that enabled a more relevant direct comparison for fracture testing of hydrogels for cartilage tissue engineering. Moreover, a target toughness value for cartilage of using this direct comparison method has been identified (348 ± 43 MPa/mm½), and the toughness discrepancy to be overcome between hydrogels and cartilage has been quantified. PMID:24700577

  12. Mesenchymal stem cells in regenerative medicine: Focus on articular cartilage and intervertebral disc regeneration.

    PubMed

    Richardson, Stephen M; Kalamegam, Gauthaman; Pushparaj, Peter N; Matta, Csaba; Memic, Adnan; Khademhosseini, Ali; Mobasheri, Reza; Poletti, Fabian L; Hoyland, Judith A; Mobasheri, Ali

    2016-04-15

    Musculoskeletal disorders represent a major cause of disability and morbidity globally and result in enormous costs for health and social care systems. Development of cell-based therapies is rapidly proliferating in a number of disease areas, including musculoskeletal disorders. Novel biological therapies that can effectively treat joint and spine degeneration are high priorities in regenerative medicine. Mesenchymal stem cells (MSCs) isolated from bone marrow (BM-MSCs), adipose tissue (AD-MSCs) and umbilical cord (UC-MSCs) show considerable promise for use in cartilage and intervertebral disc (IVD) repair. This review article focuses on stem cell-based therapeutics for cartilage and IVD repair in the context of the rising global burden of musculoskeletal disorders. We discuss the biology MSCs and chondroprogenitor cells and specifically focus on umbilical cord/Wharton's jelly derived MSCs and examine their potential for regenerative applications. We also summarize key components of the molecular machinery and signaling pathways responsible for the control of chondrogenesis and explore biomimetic scaffolds and biomaterials for articular cartilage and IVD regeneration. This review explores the exciting opportunities afforded by MSCs and discusses the challenges associated with cartilage and IVD repair and regeneration. There are still many technical challenges associated with isolating, expanding, differentiating, and pre-conditioning MSCs for subsequent implantation into degenerate joints and the spine. However, the prospect of combining biomaterials and cell-based therapies that incorporate chondrocytes, chondroprogenitors and MSCs leads to the optimistic view that interdisciplinary approaches will lead to significant breakthroughs in regenerating musculoskeletal tissues, such as the joint and the spine in the near future. PMID:26384579

  13. Cells and biomaterials in cartilage tissue engineering.

    PubMed

    Stoddart, Martin J; Grad, Sibylle; Eglin, David; Alini, Mauro

    2009-01-01

    Cartilage defects are notoriously difficult to repair and owing to the long-term prognosis of osteoarthritis, and a rapidly aging population, a need for new therapies is pressing. Cell-based therapies for cartilage regeneration were introduced into patients in the early 1990s. Since that time the technology has developed from a simple cell suspension to more complex 3D structures. Cells, both chondrocytes and stem cells, have been incorporated into scaffold material with the aim to better recreate the natural environment of the cell, while providing more structural support to withstand the large forces applied on the de novo tissue. This review aims to provide an overview of potential cell sources and different scaffold materials, which are in development for cartilage tissue engineering.

  14. Microtubules self-repair in response to mechanical stress

    NASA Astrophysics Data System (ADS)

    Schaedel, Laura; John, Karin; Gaillard, Jérémie; Nachury, Maxence V.; Blanchoin, Laurent; Théry, Manuel

    2015-11-01

    Microtubules--which define the shape of axons, cilia and flagella, and provide tracks for intracellular transport--can be highly bent by intracellular forces, and microtubule structure and stiffness are thought to be affected by physical constraints. Yet how microtubules tolerate the vast forces exerted on them remains unknown. Here, by using a microfluidic device, we show that microtubule stiffness decreases incrementally with each cycle of bending and release. Similar to other cases of material fatigue, the concentration of mechanical stresses on pre-existing defects in the microtubule lattice is responsible for the generation of more extensive damage, which further decreases microtubule stiffness. Strikingly, damaged microtubules were able to incorporate new tubulin dimers into their lattice and recover their initial stiffness. Our findings demonstrate that microtubules are ductile materials with self-healing properties, that their dynamics does not exclusively occur at their ends, and that their lattice plasticity enables the microtubules' adaptation to mechanical stresses.

  15. Microtubules self-repair in response to mechanical stress

    PubMed Central

    Schaedel, Laura; John, Karin; Gaillard, Jérémie; Nachury, Maxence V.; Blanchoin, Laurent; Théry, Manuel

    2015-01-01

    Microtubules - which define the shape of axons, cilia and flagella, and provide tracks for intracellular transport - can be highly bent by intracellular forces, and microtubule structure and stiffness are thought to be affected by physical constraints. Yet how microtubules tolerate the vast forces exerted on them remains unknown. Here, by using a microfluidic device, we show that microtubule stiffness decreases incrementally with each cycle of bending and release. Similar to other cases of material fatigue, the concentration of mechanical stresses on pre-existing defects in the microtubule lattice is responsible for the generation of larger damages, which further decrease microtubule stiffness. Strikingly, damaged microtubules were able to incorporate new tubulin dimers into their lattice and recover their initial stiffness. Our findings demonstrate that microtubules are ductile materials with self-healing properties, that their dynamics does not exclusively occur at their ends, and that their lattice plasticity enables the microtubules' adaptation to mechanical stresses. PMID:26343914

  16. Microtubules self-repair in response to mechanical stress.

    PubMed

    Schaedel, Laura; John, Karin; Gaillard, Jérémie; Nachury, Maxence V; Blanchoin, Laurent; Théry, Manuel

    2015-11-01

    Microtubules--which define the shape of axons, cilia and flagella, and provide tracks for intracellular transport--can be highly bent by intracellular forces, and microtubule structure and stiffness are thought to be affected by physical constraints. Yet how microtubules tolerate the vast forces exerted on them remains unknown. Here, by using a microfluidic device, we show that microtubule stiffness decreases incrementally with each cycle of bending and release. Similar to other cases of material fatigue, the concentration of mechanical stresses on pre-existing defects in the microtubule lattice is responsible for the generation of more extensive damage, which further decreases microtubule stiffness. Strikingly, damaged microtubules were able to incorporate new tubulin dimers into their lattice and recover their initial stiffness. Our findings demonstrate that microtubules are ductile materials with self-healing properties, that their dynamics does not exclusively occur at their ends, and that their lattice plasticity enables the microtubules' adaptation to mechanical stresses. PMID:26343914

  17. Engineering Superficial Zone Features in Tissue Engineered Cartilage

    PubMed Central

    Chen, Tony; Hilton, Matthew J.; Brown, Edward B.; Zuscik, Michael J.; Awad, Hani A.

    2013-01-01

    A major challenge in cartilage tissue engineering is the need to recreate the native tissue's anisotropic extracellular matrix structure. This anisotropy has important mechanical and biological consequences and could be crucial for integrative repair. Here we report that hydrodynamic conditions that mimic the motion-induced flow fields in between the articular surfaces in the synovial joint induce the formation of a distinct superficial layer in tissue engineered cartilage hydrogels, with enhanced production of cartilage matrix proteoglycan and type II collagen. Moreover, the flow stimulation at the surface induces the production of the surface zone protein Proteoglycan 4 (aka PRG4 or lubricin). Analysis of second harmonic generation signature of collagen in this superficial layer reveals a highly aligned fibrillar matrix that resembles the alignment pattern in native tissue's surface zone, suggesting that mimicking synovial fluid flow at the cartilage surface in hydrodynamic bioreactors could be key to creating engineered cartilage with superficial zone features. PMID:23239161

  18. Comparative potential of juvenile and adult human articular chondrocytes for cartilage tissue formation in three-dimensional biomimetic hydrogels.

    PubMed

    Smeriglio, Piera; Lai, Janice H; Dhulipala, Lakshmi; Behn, Anthony W; Goodman, Stuart B; Smith, Robert L; Maloney, William J; Yang, Fan; Bhutani, Nidhi

    2015-01-01

    Regeneration of human articular cartilage is inherently limited and extensive efforts have focused on engineering the cartilage tissue. Various cellular sources have been studied for cartilage tissue engineering including adult chondrocytes, and embryonic or adult stem cells. Juvenile chondrocytes (from donors below 13 years of age) have recently been reported to be a promising cell source for cartilage regeneration. Previous studies have compared the potential of adult and juvenile chondrocytes or adult and osteoarthritic (OA) chondrocytes. To comprehensively characterize the comparative potential of young, old, and diseased chondrocytes, here we examined cartilage formation by juvenile, adult, and OA chondrocytes in three-dimensional (3D) biomimetic hydrogels composed of poly(ethylene glycol) and chondroitin sulfate. All three human articular chondrocytes were encapsulated in the 3D biomimetic hydrogels and cultured for 3 or 6 weeks to allow maturation and extracellular matrix formation. Outcomes were analyzed using quantitative gene expression, immunofluorescence staining, biochemical assays, and mechanical testing. After 3 and 6 weeks, juvenile chondrocytes showed a greater upregulation of chondrogenic gene expression than adult chondrocytes, while OA chondrocytes showed a downregulation. Aggrecan and type II collagen deposition and glycosaminoglycan accumulation were high for juvenile and adult chondrocytes but not for OA chondrocytes. Similar trend was observed in the compressive moduli of the cartilage constructs generated by the three different chondrocytes. In conclusion, the juvenile, adult and OA chondrocytes showed differential responses in the 3D biomimetic hydrogels. The 3D culture model described here may also provide a useful tool to further study the molecular differences among chondrocytes from different stages, which can help elucidate the mechanisms for age-related decline in the intrinsic capacity for cartilage repair. PMID:25054343

  19. Application of an acoustofluidic perfusion bioreactor for cartilage tissue engineering

    PubMed Central

    Li, Siwei; Glynne-Jones, Peter; Andriotis, Orestis G.; Ching, Kuan Y.; Jonnalagadda, Umesh S.; Oreffo, Richard O. C.; Hill, Martyn

    2014-01-01

    Cartilage grafts generated using conventional static tissue engineering strategies are characterised by low cell viability, suboptimal hyaline cartilage formation and, critically, inferior mechanical competency, which limit their application for resurfacing articular cartilage defects. To address the limitations of conventional static cartilage bioengineering strategies and generate robust, scaffold-free neocartilage grafts of human articular chondrocytes, the present study utilised custom-built microfluidic perfusion bioreactors with integrated ultrasound standing wave traps. The system employed sweeping acoustic drive frequencies over the range of 890 to 910 kHz and continuous perfusion of the chondrogenic culture medium at a low-shear flow rate to promote the generation of three-dimensional agglomerates of human articular chondrocytes, and enhance cartilage formation by cells of the agglomerates via improved mechanical stimulation and mass transfer rates. Histological examination and assessment of micromechanical properties using indentation-type atomic force microscopy confirmed that the neocartilage grafts were analogous to native hyaline cartilage. Furthermore, in the ex vivo organ culture partial thickness cartilage defect model, implantation of the neocartilage grafts into defects for 16 weeks resulted in the formation of hyaline cartilage-like repair tissue that adhered to the host cartilage and contributed to significant improvements to the tissue architecture within the defects, compared to the empty defects. The study has demonstrated the first successful application of the acoustofluidic perfusion bioreactors to bioengineer scaffold-free neocartilage grafts of human articular chondrocytes that have the potential for subsequent use in second generation autologous chondrocyte implantation procedures for the repair of partial thickness cartilage defects. PMID:25272195

  20. In vivo cartilage formation from growth factor modulated articular chondrocytes.

    PubMed

    Bradham, D M; Horton, W E

    1998-07-01

    Recent procedures for autologous repair of cartilage defects may be difficult in elderly patients because of the loss of stem cells and chondrocytes that occurs with age and the slow in vitro proliferation of chondrocytes from aged cartilage. In this study secondary chondroprogenitor cells were obtained by modulating the phenotype of articular chondrocytes with growth factors and stimulating the proliferation of these cells in culture. Chondrocytes isolated from the articular cartilage of mature New Zealand White rabbits were exposed to a combination of transforming growth factor beta and basic fibroblast growth factor treatment. These cells ceased the production of Collagen II (a marker for the chondrocyte phenotype) and underwent a 136-fold increase in cell number. Next, the cells were placed in high density culture and reexpressed the chondrocyte phenotype in vitro and formed hyaline cartilage in an in vivo assay. Primary chondrocytes obtained from articular cartilage of elderly humans could be manipulated in a similar fashion in vitro. These human secondary chondroprogenitor cells formed only cartilage tissue when assayed in vivo and in tissue bioreactors. This approach may be essential for autologous repair of degenerated articular cartilage in elderly patients with osteoarthritis.

  1. Modelling cartilage mechanobiology.

    PubMed Central

    Carter, Dennis R; Wong, Marcy

    2003-01-01

    The growth, maintenance and ossification of cartilage are fundamental to skeletal development and are regulated throughout life by the mechanical cues that are imposed by physical activities. Finite element computer analyses have been used to study the role of local tissue mechanics on endochondral ossification patterns, skeletal morphology and articular cartilage thickness distributions. Using single-phase continuum material representations of cartilage, the results have indicated that local intermittent hydrostatic pressure promotes cartilage maintenance. Cyclic tensile strains (or shear), however, promote cartilage growth and ossification. Because single-phase material models cannot capture fluid exudation in articular cartilage, poroelastic (or biphasic) solid/fluid models are often implemented to study joint mechanics. In the middle and deep layers of articular cartilage where poroelastic analyses predict little fluid exudation, the cartilage phenotype is maintained by cyclic fluid pressure (consistent with the single-phase theory). In superficial articular layers the chondrocytes are exposed to tangential tensile strain in addition to the high fluid pressure. Furthermore, there is fluid exudation and matrix consolidation, leading to cell 'flattening'. As a result, the superficial layer assumes an altered, more fibrous phenotype. These computer model predictions of cartilage mechanobiology are consistent with results of in vitro cell and tissue and molecular biology experiments. PMID:14561337

  2. DNA Damage Response Factors from Diverse Pathways, Including DNA Crosslink Repair, Mediate Alternative End Joining

    PubMed Central

    Howard, Sean M.; Yanez, Diana A.; Stark, Jeremy M.

    2015-01-01

    Alternative end joining (Alt-EJ) chromosomal break repair involves bypassing classical non-homologous end joining (c-NHEJ), and such repair causes mutations often with microhomology at the repair junction. Since the mediators of Alt-EJ are not well understood, we have sought to identify DNA damage response (DDR) factors important for this repair event. Using chromosomal break reporter assays, we surveyed an RNAi library targeting known DDR factors for siRNAs that cause a specific decrease in Alt-EJ, relative to an EJ event that is a composite of Alt-EJ and c-NHEJ (Distal-EJ between two tandem breaks). From this analysis, we identified several DDR factors that are specifically important for Alt-EJ relative to Distal-EJ. While these factors are from diverse pathways, we also found that most of them also promote homologous recombination (HR), including factors important for DNA crosslink repair, such as the Fanconi Anemia factor, FANCA. Since bypass of c-NHEJ is likely important for both Alt-EJ and HR, we disrupted the c-NHEJ factor Ku70 in Fanca-deficient mouse cells and found that Ku70 loss significantly diminishes the influence of Fanca on Alt-EJ. In contrast, an inhibitor of poly ADP-ribose polymerase (PARP) causes a decrease in Alt-EJ that is enhanced by Ku70 loss. Additionally, the helicase/nuclease DNA2 appears to have distinct effects from FANCA and PARP on both Alt-EJ, as well as end resection. Finally, we found that the proteasome inhibitor Bortezomib, a cancer therapeutic that has been shown to disrupt FANC signaling, causes a significant reduction in both Alt-EJ and HR, relative to Distal-EJ, as well as a substantial loss of end resection. We suggest that several distinct DDR functions are important for Alt-EJ, which include promoting bypass of c-NHEJ and end resection. PMID:25629353

  3. Role of Cell Cycle Regulation and MLH1, A Key DNA Mismatch Repair Protein, In Adaptive Survival Responses. Final Report

    SciTech Connect

    David A. Boothman

    1999-08-11

    Due to several interesting findings on both adaptive survival responses (ASRs) and DNA mismatch repair (MMR), this grant was separated into two discrete Specific Aim sets (each with their own discrete hypotheses). The described experiments were simultaneously performed.

  4. Decellularized cartilage matrix as a novel biomatrix for cartilage tissue-engineering applications.

    PubMed

    Schwarz, Silke; Koerber, Ludwig; Elsaesser, Alexander F; Goldberg-Bockhorn, Eva; Seitz, Andreas M; Dürselen, Lutz; Ignatius, Anita; Walther, Paul; Breiter, Roman; Rotter, Nicole

    2012-11-01

    Damage of cartilage structures in the head and neck region as well as in orthopedic sites are frequently caused by trauma, tumor resection, or congenital defects. Despite a high demand in many clinical fields, until today, no adequate cartilage replacement matrix is available for these fields of application. Materials that are clinically applied for joint cartilage repair still need optimization due to difficult intraoperative handling and risk of early mechanical damage. We have developed and applied a novel chemical process to completely decellularize and sterilize human and porcine cartilage tissues (meniscus cartilage and nasal septum) to generate a new type of bioimplant matrix. To characterize this matrix and to determine the effect of the decellularization process, the content of denatured collagen (w(D)) and the content of glycosaminoglycans (GAGs) (w(G)) were determined. Possible cytotoxic effects and cellular compatibility of the matrix in vitro have been examined by seeding processed cartilage biomatrices with human primary chondrocytes as well as murine fibroblasts (L929). Vitality and state of metabolism of cells were measured using MTS assays. Both cell types adhered to scaffold surfaces and proliferated. No areas of growth inhibition or cytotoxic effects were detected. New synthesis of cartilage-specific extracellular matrix was observed. By histological staining, electron microscopy, and μCT analysis, an increase of matrix porosity, complete cell elimination, and high GAG removal were demonstrated. Being from natural-origin, processed xenogenic and allogeneic cartilage biomatrices are highly versatile with regard to shape, size, and biomechanics, making them promising candidates for various biomedical applications.

  5. Cartilage histomorphometry.

    PubMed

    Hunziker, Ernst B

    2007-01-01

    In rheumatology and joint research, as in other fields, a purely descriptional appqoach to morphology cannot satisfy the exactions of modern clinical medicine. Investigators now appreciate the need to gauge pathological changes and their response to treatment by quantifying susceptible structural parameters. But the desired information respecting three-dimensional structures must be gleaned from either actual or virtual two-dimensional sections through the tissue. This information can be obtained only if the laws governing stereology are respected. In this chapter, the stereological principles that must be applied, and the practical methods that have been devised, to yield unbiased estimates of the most commonly determined structural parameters, namely, volume, surface area and number, are summarized.

  6. Melatonin enhances DNA repair capacity possibly by affecting genes involved in DNA damage responsive pathways

    PubMed Central

    2013-01-01

    Background Melatonin, a hormone-like substance involved in the regulation of the circadian rhythm, has been demonstrated to protect cells against oxidative DNA damage and to inhibit tumorigenesis. Results In the current study, we investigated the effect of melatonin on DNA strand breaks using the alkaline DNA comet assay in breast cancer (MCF-7) and colon cancer (HCT-15) cell lines. Our results demonstrated that cells pretreated with melatonin had significantly shorter Olive tail moments compared to non-melatonin treated cells upon mutagen (methyl methanesulfonate, MMS) exposure, indicating an increased DNA repair capacity after melatonin treatment. We further examined the genome-wide gene expression in melatonin pretreated MCF-7 cells upon carcinogen exposure and detected altered expression of many genes involved in multiple DNA damage responsive pathways. Genes exhibiting altered expression were further analyzed for functional interrelatedness using network- and pathway-based bioinformatics analysis. The top functional network was defined as having relevance for “DNA Replication, Recombination, and Repair, Gene Expression, [and] Cancer”. Conclusions These findings suggest that melatonin may enhance DNA repair capacity by affecting several key genes involved in DNA damage responsive pathways. PMID:23294620

  7. Cytogenetic Response to Ionizing Radiation Exposure in Human Fibroblasts with Suppressed Expression of Non-DSB Repair Genes

    NASA Technical Reports Server (NTRS)

    Zhang, Ye; Rohde, Larry H.; Emami, Kamal; Hammond, Dianne; Mehta, Satish K.; Jeevarajan, Antony S.; Pierson, Duane L.; Wu, Honglu

    2009-01-01

    Changes of gene expression profile are one of the most important biological responses in living cells after ionizing radiation (IR) exposure. Although some studies have shown that genes up-regulated by IR may play important roles in DNA damage repair, the relationship between the regulation of gene expression by IR, particularly genes not known for their roles in double-strand break (DSB) repair, and its impact on cytogenetic responses has not been well studied. The purpose of this study is to identify new roles of IR inducible genes in radiation-induced chromosome aberrations and micronuclei formation. In the study, the expression of 25 genes selected on the basis of their transcriptional changes in response to IR was individually knocked down by small interfering RNA in human fibroblast cells. Frequencies of micronuclei (MN) formation and chromosome aberrations were measured to determine the efficiency of cytogenetic repair, and the fraction of bi-nucleated cells in the MN analysis was used as a marker for cell cycle progression. In response to gamma radiation, the formation of MN was significantly increased by suppressed expression of five genes: Ku70 (DSB repair pathway), XPA (nucleotide excision repair pathway), RPA1 (mismatch repair pathway), RAD17 and RBBP8 (cell cycle control). Knocked-down expression of four genes (MRE11A, RAD51 in the DSB pathway, SESN1, and SUMO1) significantly inhibited cell cycle progression, possibly because of severe impairment of DNA damage repair. Moreover, decreased XPA, p21, or MLH1 expression resulted in both significantly enhanced cell cycle progression and increased yields of chromosome aberrations, indicating that these gene products modulate both cell cycle control and DNA damage repair. Nine of these eleven genes, whose knock-down expression affected cytogenetic repair, were up-regulated in cells exposed to gamma radiation, suggesting that genes transcriptionally modulated by IR were critical to regulate IR

  8. Lubricin is expressed in chondrocytes derived from osteoarthritic cartilage encapsulated in poly (ethylene glycol) diacrylate scaffold

    PubMed Central

    Musumeci, G.; Loreto, C.; Carnazza, M.L.; Coppolino, F.; Cardile, V.; Leonardi, R.

    2011-01-01

    Osteoarthritis (OA) is characterized by degenerative changes within joints that involved quantitative and/or qualitative alterations of cartilage and synovial fluid lubricin, a mucinous glycoprotein secreted by synovial fibroblasts and chondrocytes. Modern therapeutic methods, including tissue-engineering techniques, have been used to treat mechanical damage of the articular cartilage but to date there is no specific and effective treatment. This study aimed at investigating lubricin immunohistochemical expression in cartilage explant from normal and OA patients and in cartilage constructions formed by Poly (ethylene glycol) (PEG) based hydrogels (PEG-DA) encapsulated OA chondrocytes. The expression levels of lubricin were studied by immunohistochemistry: i) in tissue explanted from OA and normal human cartilage; ii) in chondrocytes encapsulated in hydrogel PEGDA from OA and normal human cartilage. Moreover, immunocytochemical and western blot analysis were performed in monolayer cells from OA and normal cartilage. The results showed an increased expression of lubricin in explanted tissue and in monolayer cells from normal cartilage, and a decreased expression of lubricin in OA cartilage. The chondrocytes from OA cartilage after 5 weeks of culture in hydrogels (PEGDA) showed an increased expression of lubricin compared with the control cartilage. The present study demonstrated that OA chondrocytes encapsulated in PEGDA, grown in the scaffold and were able to restore lubricin biosynthesis. Thus our results suggest the possibility of applying autologous cell transplantation in conjunction with scaffold materials for repairing cartilage lesions in patients with OA to reduce at least the progression of the disease. PMID:22073377

  9. Lubricin is expressed in chondrocytes derived from osteoarthritic cartilage encapsulated in poly (ethylene glycol) diacrylate scaffold.

    PubMed

    Musumeci, G; Loreto, C; Carnazza, M L; Coppolino, F; Cardile, V; Leonardi, R

    2011-01-01

    Osteoarthritis (OA) is characterized by degenerative changes within joints that involved quantitative and/or qualitative alterations of cartilage and synovial fluid lubricin, a mucinous glycoprotein secreted by synovial fibroblasts and chondrocytes. Modern therapeutic methods, including tissue-engineering techniques, have been used to treat mechanical damage of the articular cartilage but to date there is no specific and effective treatment. This study aimed at investigating lubricin immunohistochemical expression in cartilage explant from normal and OA patients and in cartilage constructions formed by Poly (ethylene glycol) (PEG) based hydrogels (PEG-DA) encapsulated OA chondrocytes. The expression levels of lubricin were studied by immunohistochemistry: i) in tissue explanted from OA and normal human cartilage; ii) in chondrocytes encapsulated in hydrogel PEGDA from OA and normal human cartilage. Moreover, immunocytochemical and western blot analysis were performed in monolayer cells from OA and normal cartilage. The results showed an increased expression of lubricin in explanted tissue and in monolayer cells from normal cartilage, and a decreased expression of lubricin in OA cartilage. The chondrocytes from OA cartilage after 5 weeks of culture in hydrogels (PEGDA) showed an increased expression of lubricin compared with the control cartilage. The present study demonstrated that OA chondrocytes encapsulated in PEGDA, grown in the scaffold and were able to restore lubricin biosynthesis. Thus our results suggest the possibility of applying autologous cell transplantation in conjunction with scaffold materials for repairing cartilage lesions in patients with OA to reduce at least the progression of the disease.

  10. Cartilage conduction hearing.

    PubMed

    Shimokura, Ryota; Hosoi, Hiroshi; Nishimura, Tadashi; Yamanaka, Toshiaki; Levitt, Harry

    2014-04-01

    Sound information is known to travel to the cochlea via either air or bone conduction. However, a vibration signal, delivered to the aural cartilage via a transducer, can also produce a clearly audible sound. This type of conduction has been termed "cartilage conduction." The aural cartilage forms the outer ear and is distributed around the exterior half of the external auditory canal. In cartilage conduction, the cartilage and transducer play the roles of a diaphragm and voice coil of a loudspeaker, respectively. There is a large gap between the impedances of cartilage and skull bone, such that cartilage vibrations are not easily transmitted through bone. Thus, these methods of conduction are distinct. In this study, force was used to apply a transducer to aural cartilage, and it was found that the sound in the auditory canal was amplified, especially for frequencies below 2 kHz. This effect was most pronounced at an application force of 1 N, which is low enough to ensure comfort in the design of hearing aids. The possibility of using force adjustments to vary amplification may also have applications for cell phone design.

  11. Photoactivated methods for enabling cartilage-to-cartilage tissue fixation

    NASA Astrophysics Data System (ADS)

    Sitterle, Valerie B.; Roberts, David W.

    2003-06-01

    The present study investigates whether photoactivated attachment of cartilage can provide a viable method for more effective repair of damaged articular surfaces by providing an alternative to sutures, barbs, or fibrin glues for initial fixation. Unlike artificial materials, biological constructs do not possess the initial strength for press-fitting and are instead sutured or pinned in place, typically inducing even more tissue trauma. A possible alternative involves the application of a photosensitive material, which is then photoactivated with a laser source to attach the implant and host tissues together in either a photothermal or photochemical process. The photothermal version of this method shows potential, but has been almost entirely applied to vascularized tissues. Cartilage, however, exhibits several characteristics that produce appreciable differences between applying and refining these techniques when compared to previous efforts involving vascularized tissues. Preliminary investigations involving photochemical photosensitizers based on singlet oxygen and electron transfer mechanisms are discussed, and characterization of the photodynamic effects on bulk collagen gels as a simplified model system using FTIR is performed. Previous efforts using photothermal welding applied to cartilaginous tissues are reviewed.

  12. Cartilage transplantation techniques for talar cartilage lesions.

    PubMed

    Mitchell, Matthew E; Giza, Eric; Sullivan, Martin R

    2009-07-01

    Talar articular cartilage is known to differ significantly from knee cartilage. Even so, recommendations for the treatment of talar cartilage lesions have been based on strategies for the knee. Arthroscopic management of osteochondral lesions of the talus is well documented. Results have been favorable with reparative techniques such as débridement with curettage and débridement with drilling, whether undertaken via early open techniques or more recent arthroscopic procedures. Salvage of failed reparative techniques is controversial. Early efforts to salvage failed débridement focused on osteochondral allografts and autografts that used the knee as a donor site. Results of these restorative techniques have been favorable, but concerns have been raised regarding knee donor site morbidity, the use of malleolar osteotomy, and incomplete restoration of the talar articular surface. More recent restorative techniques developed for the knee have been adapted for the ankle, such as autologous chondrocyte implantation and matrix-induced autologous chondrocyte implantation.

  13. 3D Hydrogel Scaffolds for Articular Chondrocyte Culture and Cartilage Generation

    PubMed Central

    Yang, Fan; Bhutani, Nidhi

    2015-01-01

    Human articular cartilage is highly susceptible to damage and has limited self-repair and regeneration potential. Cell-based strategies to engineer cartilage tissue offer a promising solution to repair articular cartilage. To select the optimal cell source for tissue repair, it is important to develop an appropriate culture platform to systematically examine the biological and biomechanical differences in the tissue-engineered cartilage by different cell sources. Here we applied a three-dimensional (3D) biomimetic hydrogel culture platform to systematically examine cartilage regeneration potential of juvenile, adult, and osteoarthritic (OA) chondrocytes. The 3D biomimetic hydrogel consisted of synthetic component poly(ethylene glycol) and bioactive component chondroitin sulfate, which provides a physiologically relevant microenvironment for in vitro culture of chondrocytes. In addition, the scaffold may be potentially used for cell delivery for cartilage repair in vivo. Cartilage tissue engineered in the scaffold can be evaluated using quantitative gene expression, immunofluorescence staining, biochemical assays, and mechanical testing. Utilizing these outcomes, we were able to characterize the differential regenerative potential of chondrocytes of varying age, both at the gene expression level and in the biochemical and biomechanical properties of the engineered cartilage tissue. The 3D culture model could be applied to investigate the molecular and functional differences among chondrocytes and progenitor cells from different stages of normal or aberrant development. PMID:26484414

  14. DNA Repair Biomarkers Predict Response to Neoadjuvant Chemoradiotherapy in Esophageal Cancer

    SciTech Connect

    Alexander, Brian M.; Niemierko, Andrzej; Weaver, David T.; Mak, Raymond H.; Fidias, Panagiotis; Wain, John; Choi, Noah C.

    2012-05-01

    Purpose: The addition of neoadjuvant chemoradiotherapy prior to surgical resection for esophageal cancer has improved clinical outcomes in some trials. Pathologic complete response (pCR) following neoadjuvant therapy is associated with better clinical outcome in these patients, but only 22% to 40% of patients achieve pCR. Because both chemotherapy and radiotherapy act by inducing DNA damage, we analyzed proteins selected from multiple DNA repair pathways, using quantitative immunohistochemistry coupled with a digital pathology platform, as possible biomarkers of treatment response and clinical outcome. Methods and Materials: We identified 79 patients diagnosed with esophageal cancer between October 1994 and September 2002, with biopsy tissue available, who underwent neoadjuvant chemoradiotherapy prior to surgery at the Massachusetts General Hospital and used their archived, formalin-fixed, paraffin-embedded biopsy samples to create tissue microarrays (TMA). TMA sections were stained using antibodies against proteins in various DNA repair pathways including XPF, FANCD2, PAR, MLH1, PARP1, and phosphorylated MAPKAP kinase 2 (pMK2). Stained TMA slides were evaluated using machine-based image analysis, and scoring incorporated both the intensity and the quantity of positive tumor nuclei. Biomarker scores and clinical data were assessed for correlations with clinical outcome. Results: Higher scores for MLH1 (p = 0.018) and lower scores for FANCD2 (p = 0.037) were associated with pathologic response to neoadjuvant chemoradiation on multivariable analysis. Staining of MLH1, PARP1, XPF, and PAR was associated with recurrence-free survival, and staining of PARP1 and FANCD2 was associated with overall survival on multivariable analysis. Conclusions: DNA repair proteins analyzed by immunohistochemistry may be useful as predictive markers for response to neoadjuvant chemoradiotherapy in patients with esophageal cancer. These results are hypothesis generating and need

  15. Some biochemical characteristics and water exchange in human articular cartilage in osteoarthrosis.

    PubMed

    Nikolaeva, S S; Roshchina, A A; Zon Chkhol, Kim; Bykov, V A; Rebrova, G A; Koroleva, O A; Yakovleva, L V; Abramov, Yu V; Rebrov, L B

    2002-05-01

    Rearrangement of intra- and intermolecular bonds in collagen molecule, disaggregation of proteoglycans and their elimination from cartilage involved in osteoarthrosis are responsible for water accumulation and its increased mobility in cartilage.

  16. The human DEK oncogene regulates DNA damage response signaling and repair

    PubMed Central

    Kavanaugh, Gina M.; Wise-Draper, Trisha M.; Morreale, Richard J.; Morrison, Monique A.; Gole, Boris; Schwemberger, Sandy; Tichy, Elisia D.; Lu, Lu; Babcock, George F.; Wells, James M.; Drissi, Rachid; Bissler, John J.; Stambrook, Peter J.; Andreassen, Paul R.; Wiesmüller, Lisa; Wells, Susanne I.

    2011-01-01

    The human DEK gene is frequently overexpressed and sometimes amplified in human cancer. Consistent with oncogenic functions, Dek knockout mice are partially resistant to chemically induced papilloma formation. Additionally, DEK knockdown in vitro sensitizes cancer cells to DNA damaging agents and induces cell death via p53-dependent and -independent mechanisms. Here we report that DEK is important for DNA double-strand break repair. DEK depletion in human cancer cell lines and xenografts was sufficient to induce a DNA damage response as assessed by detection of γH2AX and FANCD2. Phosphorylation of H2AX was accompanied by contrasting activation and suppression, respectively, of the ATM and DNA-PK pathways. Similar DNA damage responses were observed in primary Dek knockout mouse embryonic fibroblasts (MEFs), along with increased levels of DNA damage and exaggerated induction of senescence in response to genotoxic stress. Importantly, Dek knockout MEFs exhibited distinct defects in non-homologous end joining (NHEJ) when compared to their wild-type counterparts. Taken together, the data demonstrate new molecular links between DEK and DNA damage response signaling pathways, and suggest that DEK contributes to DNA repair. PMID:21653549

  17. The role and clinical significance of DNA damage response and repair pathways in primary brain tumors

    PubMed Central

    2013-01-01

    Primary brain tumors, in particular, glioblastoma multiforme (GBM), continue to have dismal survivability despite advances in treating other neoplasms. The goal of new anti-glioma therapy development is to increase their therapeutic ratios by enhancing tumor control and/or decreasing the severity and incidence of side effects. Because radiotherapy and most chemotherapy agents rely on DNA damage, the cell’s DNA damage repair and response (DRR) pathways may hold the key to new therapeutic strategies. DNA double-strand breaks (DSBs) generated by ionizing radiation and chemotherapeutic agents are the most lethal form of damage, and are repaired via either homologous recombination (HR) or non-homologous end-joining (NHEJ) pathways. Understanding and exploitation of the differences in the use of these repair pathways between tumor and normal brain cells will allow for an increase in tumor cell killing and decreased normal tissue damage. A literature review and discussion on new strategies which can improve the anti-glioma therapeutic ratio by differentially targeting HR and NHEJ function in tumor and normal neuronal tissues is the focus of this article. PMID:23388100

  18. Pitx2 promotes heart repair by activating the antioxidant response after cardiac injury.

    PubMed

    Tao, Ge; Kahr, Peter C; Morikawa, Yuka; Zhang, Min; Rahmani, Mahdis; Heallen, Todd R; Li, Lele; Sun, Zhao; Olson, Eric N; Amendt, Brad A; Martin, James F

    2016-06-01

    Myocardial infarction results in compromised myocardial function and heart failure owing to insufficient cardiomyocyte self-renewal. Unlike many vertebrates, mammalian hearts have only a transient neonatal renewal capacity. Reactivating primitive reparative ability in the mature mammalian heart requires knowledge of the mechanisms that promote early heart repair. By testing an established Hippo-deficient heart regeneration mouse model for factors that promote renewal, here we show that the expression of Pitx2 is induced in injured, Hippo-deficient ventricles. Pitx2-deficient neonatal mouse hearts failed to repair after apex resection, whereas adult mouse cardiomyocytes with Pitx2 gain-of-function efficiently regenerated after myocardial infarction. Genomic analyses indicated that Pitx2 activated genes encoding electron transport chain components and reactive oxygen species scavengers. A subset of Pitx2 target genes was cooperatively regulated with the Hippo pathway effector Yap. Furthermore, Nrf2, a regulator of the antioxidant response, directly regulated the expression and subcellular localization of Pitx2. Pitx2 mutant myocardium had increased levels of reactive oxygen species, while antioxidant supplementation suppressed the Pitx2 loss-of-function phenotype. These findings reveal a genetic pathway activated by tissue damage that is essential for cardiac repair. PMID:27251288

  19. DNA Damage Response and DNA Repair in Skeletal Myocytes From a Mouse Model of Spinal Muscular Atrophy.

    PubMed

    Fayzullina, Saniya; Martin, Lee J

    2016-09-01

    We studied DNA damage response (DDR) and DNA repair capacities of skeletal muscle cells from a mouse model of infantile spinal muscular atrophy (SMA) caused by loss-of-function mutation of survival of motor neuron (Smn). Primary myocyte cultures derived from skeletal muscle satellite cells of neonatal control and mutant SMN mice had similar myotube length, myonuclei, satellite cell marker Pax7 and differentiated myotube marker myosin, and acetylcholine receptor clustering. DNA damage was induced in differentiated skeletal myotubes by γ-irradiation, etoposide, and methyl methanesulfonate (MMS). Unexposed control and SMA myotubes had stable genome integrity. After γ-irradiation and etoposide, myotubes repaired most DNA damage equally. Control and mutant myotubes exposed to MMS exhibited equivalent DNA damage without repair. Control and SMA myotube nuclei contained DDR proteins phospho-p53 and phospho-H2AX foci that, with DNA damage, dispersed and then re-formed similarly after recovery. We conclude that mouse primary satellite cell-derived myotubes effectively respond to and repair DNA strand-breaks, while DNA alkylation repair is underrepresented. Morphological differentiation, genome stability, genome sensor, and DNA strand-break repair potential are preserved in mouse SMA myocytes; thus, reduced SMN does not interfere with myocyte differentiation, genome integrity, and DNA repair, and faulty DNA repair is unlikely pathogenic in SMA. PMID:27452406

  20. Autophagy modulates articular cartilage vesicle formation in primary articular chondrocytes.

    PubMed

    Rosenthal, Ann K; Gohr, Claudia M; Mitton-Fitzgerald, Elizabeth; Grewal, Rupinder; Ninomiya, James; Coyne, Carolyn B; Jackson, William T

    2015-05-22

    Chondrocyte-derived extracellular organelles known as articular cartilage vesicles (ACVs) participate in non-classical protein secretion, intercellular communication, and pathologic calcification. Factors affecting ACV formation and release remain poorly characterized; although in some cell types, the generation of extracellular vesicles is associated with up-regulation of autophagy. We sought to determine the role of autophagy in ACV production by primary articular chondrocytes. Using an innovative dynamic model with a light scatter nanoparticle counting apparatus, we determined the effects of autophagy modulators on ACV number and content in conditioned medium from normal adult porcine and human osteoarthritic chondrocytes. Healthy articular chondrocytes release ACVs into conditioned medium and show significant levels of ongoing autophagy. Rapamycin, which promotes autophagy, increased ACV numbers in a dose- and time-dependent manner associated with increased levels of autophagy markers and autophagosome formation. These effects were suppressed by pharmacologic autophagy inhibitors and short interfering RNA for ATG5. Caspase-3 inhibition and a Rho/ROCK inhibitor prevented rapamycin-induced increases in ACV number. Osteoarthritic chondrocytes, which are deficient in autophagy, did not increase ACV number in response to rapamycin. SMER28, which induces autophagy via an mTOR-independent mechanism, also increased ACV number. ACVs induced under all conditions had similar ecto-enzyme specific activities and types of RNA, and all ACVs contained LC3, an autophagosome-resident protein. These findings identify autophagy as a critical participant in ACV formation, and augment our understanding of ACVs in cartilage disease and repair. PMID:25869133

  1. Autophagy modulates articular cartilage vesicle formation in primary articular chondrocytes.

    PubMed

    Rosenthal, Ann K; Gohr, Claudia M; Mitton-Fitzgerald, Elizabeth; Grewal, Rupinder; Ninomiya, James; Coyne, Carolyn B; Jackson, William T

    2015-05-22

    Chondrocyte-derived extracellular organelles known as articular cartilage vesicles (ACVs) participate in non-classical protein secretion, intercellular communication, and pathologic calcification. Factors affecting ACV formation and release remain poorly characterized; although in some cell types, the generation of extracellular vesicles is associated with up-regulation of autophagy. We sought to determine the role of autophagy in ACV production by primary articular chondrocytes. Using an innovative dynamic model with a light scatter nanoparticle counting apparatus, we determined the effects of autophagy modulators on ACV number and content in conditioned medium from normal adult porcine and human osteoarthritic chondrocytes. Healthy articular chondrocytes release ACVs into conditioned medium and show significant levels of ongoing autophagy. Rapamycin, which promotes autophagy, increased ACV numbers in a dose- and time-dependent manner associated with increased levels of autophagy markers and autophagosome formation. These effects were suppressed by pharmacologic autophagy inhibitors and short interfering RNA for ATG5. Caspase-3 inhibition and a Rho/ROCK inhibitor prevented rapamycin-induced increases in ACV number. Osteoarthritic chondrocytes, which are deficient in autophagy, did not increase ACV number in response to rapamycin. SMER28, which induces autophagy via an mTOR-independent mechanism, also increased ACV number. ACVs induced under all conditions had similar ecto-enzyme specific activities and types of RNA, and all ACVs contained LC3, an autophagosome-resident protein. These findings identify autophagy as a critical participant in ACV formation, and augment our understanding of ACVs in cartilage disease and repair.

  2. Temporal assessment of ribose treatment on self-assembled articular cartilage constructs

    PubMed Central

    Eleswarapu, Sriram V.; Chen, Justin A.; Athanasiou, Kyriacos A.

    2011-01-01

    Articular cartilage cannot repair itself in response to degradation from injury or osteoarthritis. As such, there is a substantial clinical need for replacements of damaged cartilage. Tissue engineering aims to fulfill this need by developing replacement tissues in vitro. A major goal of cartilage tissue engineering is to produce tissues with robust biochemical and biomechanical properties. One technique that has been proposed to improve these properties in engineered tissue is the use of non-enzymatic glycation to induce collagen crosslinking, an attractive solution that may avoid the risks of cytotoxicity posed by conventional crosslinking agents such as glutaraldehyde. The objectives of this study were 1) to determine whether continuous application of ribose would enhance biochemical and biomechanical properties of self-assembled articular cartilage constructs, and 2) to identify an optimal time window for continuous ribose treatment. Self-assembled constructs were grown for 4 weeks using a previously established method and were subjected to continuous 7-day treatment with 30 mM ribose during culture weeks 1, 2, 3, or 4, or for the entire 4-week culture. Control constructs were grown in parallel, and all groups were evaluated for gross morphology, histology, cellularity, collagen and sulfated glycosaminoglycan (GAG) content, and compressive and tensile mechanical properties. Compared to control constructs, it was found that treatment with ribose during week 2 and for the entire duration of culture resulted in significant 62% and 40% increases in compressive stiffness, respectively; significant 66% and 44% increases in tensile stiffness; and significant 50% and 126% increases in tensile strength. Similar statistically significant trends were observed for collagen and GAG. In contrast, constructs treated with ribose during week 1 had poorer biochemical and biomechanical properties, although they were significantly larger and more cellular than all other groups. We

  3. Contributions of DNA repair and damage response pathways to the non-linear genotoxic responses of alkylating agents.

    PubMed

    Klapacz, Joanna; Pottenger, Lynn H; Engelward, Bevin P; Heinen, Christopher D; Johnson, George E; Clewell, Rebecca A; Carmichael, Paul L; Adeleye, Yeyejide; Andersen, Melvin E

    2016-01-01

    From a risk assessment perspective, DNA-reactive agents are conventionally assumed to have genotoxic risks at all exposure levels, thus applying a linear extrapolation for low-dose responses. New approaches discussed here, including more diverse and sensitive methods for assessing DNA damage and DNA repair, strongly support the existence of measurable regions where genotoxic responses with increasing doses are insignificant relative to control. Model monofunctional alkylating agents have in vitro and in vivo datasets amenable to determination of points of departure (PoDs) for genotoxic effects. A session at the 2013 Society of Toxicology meeting provided an opportunity to survey the progress in understanding the biological basis of empirically-observed PoDs for DNA alkylating agents. Together with the literature published since, this review discusses cellular pathways activated by endogenous and exogenous alkylation DNA damage. Cells have evolved conserved processes that monitor and counteract a spontaneous steady-state level of DNA damage. The ubiquitous network of DNA repair pathways serves as the first line of defense for clearing of the DNA damage and preventing mutation. Other biological pathways discussed here that are activated by genotoxic stress include post-translational activation of cell cycle networks and transcriptional networks for apoptosis/cell death. The interactions of various DNA repair and DNA damage response pathways provide biological bases for the observed PoD behaviors seen with genotoxic compounds. Thus, after formation of DNA adducts, the activation of cellular pathways can lead to the avoidance of a mutagenic outcome. The understanding of the cellular mechanisms acting within the low-dose region will serve to better characterize risks from exposures to DNA-reactive agents at environmentally-relevant concentrations. PMID:27036068

  4. Contributions of DNA repair and damage response pathways to the non-linear genotoxic responses of alkylating agents.

    PubMed

    Klapacz, Joanna; Pottenger, Lynn H; Engelward, Bevin P; Heinen, Christopher D; Johnson, George E; Clewell, Rebecca A; Carmichael, Paul L; Adeleye, Yeyejide; Andersen, Melvin E

    2016-01-01

    From a risk assessment perspective, DNA-reactive agents are conventionally assumed to have genotoxic risks at all exposure levels, thus applying a linear extrapolation for low-dose responses. New approaches discussed here, including more diverse and sensitive methods for assessing DNA damage and DNA repair, strongly support the existence of measurable regions where genotoxic responses with increasing doses are insignificant relative to control. Model monofunctional alkylating agents have in vitro and in vivo datasets amenable to determination of points of departure (PoDs) for genotoxic effects. A session at the 2013 Society of Toxicology meeting provided an opportunity to survey the progress in understanding the biological basis of empirically-observed PoDs for DNA alkylating agents. Together with the literature published since, this review discusses cellular pathways activated by endogenous and exogenous alkylation DNA damage. Cells have evolved conserved processes that monitor and counteract a spontaneous steady-state level of DNA damage. The ubiquitous network of DNA repair pathways serves as the first line of defense for clearing of the DNA damage and preventing mutation. Other biological pathways discussed here that are activated by genotoxic stress include post-translational activation of cell cycle networks and transcriptional networks for apoptosis/cell death. The interactions of various DNA repair and DNA damage response pathways provide biological bases for the observed PoD behaviors seen with genotoxic compounds. Thus, after formation of DNA adducts, the activation of cellular pathways can lead to the avoidance of a mutagenic outcome. The understanding of the cellular mechanisms acting within the low-dose region will serve to better characterize risks from exposures to DNA-reactive agents at environmentally-relevant concentrations.

  5. Improved cartilage integration and interfacial strength after enzymatic treatment in a cartilage transplantation model.

    PubMed

    van de Breevaart Bravenboer, Jarno; In der Maur, Caroline D; Bos, P Koen; Feenstra, Louw; Verhaar, Jan A N; Weinans, Harrie; van Osch, Gerjo J V M

    2004-01-01

    The objective of the present study was to investigate whether treatment of articular cartilage with hyaluronidase and collagenase enhances histological and mechanical integration of a cartilage graft into a defect. Discs of 3 mm diameter were taken from 8-mm diameter bovine cartilage explants. Both discs and annulus were either treated for 24 hours with 0.1% hyaluronidase followed by 24 hours with 10 U/ml collagenase or left untreated (controls). Discs and annulus were reassembled and implanted subcutaneously in nude mice for 5 weeks. Integration of disc with surrounding cartilage was assessed histologically and tested biomechanically by performing a push-out test. After 5 weeks a significant increase in viable cell counts was seen in wound edges of the enzyme-treated group as compared with controls. Furthermore, matrix integration (expressed as a percentage of the total interface length that was connected; mean +/- standard error) was 83 +/- 15% in the treated samples versus 44 +/- 40% in the untreated controls. In the enzyme-treated group only, picro-Sirius Red staining revealed collagen crossing the interface perpendicular to the wound surface. Immunohistochemical analyses demonstrated that the interface tissue contained cartilage-specific collagen type II. Collagen type I was found only in a small region of fibrous tissue at the level of the superficial layer, and collagen type III was completely absent in both groups. A significant difference in interfacial strength was found using the push-out test: 1.32 +/- 0.15 MPa in the enzyme-treated group versus 0.84 +/- 0.14 MPa in the untreated controls. The study shows that enzyme treatment of cartilage wounds increases histological integration and improves biomechanical bonding strength. Enzymatic treatment may represent a promising addition to current techniques for articular cartilage repair.

  6. Analysis of friction between articular cartilage and polyvinyl alcohol hydrogel artificial cartilage.

    PubMed

    Li, Feng; Wang, Anmin; Wang, Chengtao

    2016-05-01

    Many biomaterials are being used to repair damaged articular cartilage. In particular, poly vinyl alcohol hydrogel has similar mechanical properties to natural cartilage under compressive and shearing loading. Here, three-factor and two-level friction experiments and long-term tests were conducted to better evaluate its tribological properties. The friction coefficient between articular cartilage and the poly vinyl alcohol hydrogel depended primarily on the three factors of load, speed, and lubrication. When the speed increased from 10 to 20 mm/s under a load of 10 N, the friction coefficient increased from 0.12 to 0.147. When the lubricant was changed from Ringer's solution to a hyaluronic acid solution, the friction coefficient decreased to 0.084 with loads as high as 22 N. The poly vinyl alcohol hydrogel was severely damaged and lost its top surface layers, which were transferred to the articular cartilage surface. Wear was observed in the surface morphologies, which indicated the occurrence of surface adhesion of bovine cartilage. Surface fatigue and adhesive wear was the dominant wear mechanism. PMID:26970769

  7. Septal cartilage tissue engineering: new horizons.

    PubMed

    Greene, Jacqueline J; Watson, Deborah

    2010-10-01

    Cartilage tissue engineering is a dynamically changing field that has the potential to address some of the tissue repair challenges seen in nasal and craniofacial reconstructive surgeries. The scope of the problem includes limited autologous tissue availability, donor site morbidity associated with the harvesting of these tissue grafts, and the risk of an immune reaction to allogenic or synthetic implants that might be used as alternatives. Current tissue engineering strategies involve harvesting a small biopsy specimen from a patient and then isolating chondrocytes through enzymatic digestion of the extracellular matrix. These isolated chondrocytes can be expanded in monolayer and reseeded into a three-dimensional scaffold that could potentially be used as autologous surgical grafts. Using cell-expansion techniques, it would be feasible to generate abundant amounts of cartilage in defined shapes and sizes. The ideal tissue-engineered cartilage would resemble native tissue in terms of its biochemical, structural, and metabolic properties so that it could restore stability, function, and contour to the damaged or defective facial region. In this article, emerging technology and major challenges are described to highlight recent advances and overall trends within septal cartilage tissue engineering.

  8. Three-dimensional collagen architecture in bovine articular cartilage.

    PubMed

    Jeffery, A K; Blunn, G W; Archer, C W; Bentley, G

    1991-09-01

    The three-dimensional architecture of bovine articular cartilage collagen and its relationship to split lines has been studied with scanning electron microscopy. In the middle and superficial zones, collagen was organised in a layered or leaf-like manner. The orientation was vertical in the intermediate zone, curving to become horizontal and parallel to the articular surface in the superficial zone. Each leaf consisted of a fine network of collagen fibrils. Adjacent leaves merged or were closely linked by bridging fibrils and were arranged according to the split-line pattern. The surface layer (lamina splendens) was morphologically distinct. Although ordered, the overall collagen structure was different in each plane (anisotropic) a property described in previous morphological and biophysical studies. As all components of the articular cartilage matrix interact closely, the three-dimensional organisation of collagen is important when considering cartilage function and the processes of cartilage growth, injury and repair. PMID:1894669

  9. Namaste (counterbalancing) technique: Overcoming warping in costal cartilage

    PubMed Central

    Agrawal, Kapil S.; Bachhav, Manoj; Shrotriya, Raghav

    2015-01-01

    Background: Indian noses are broader and lack projection as compared to other populations, hence very often need augmentation, that too by large volume. Costal cartilage remains the material of choice in large volume augmentations and repair of complex primary and secondary nasal deformities. One major disadvantage of costal cartilage grafts (CCG) which offsets all other advantages is the tendency to warp and become distorted over a period of time. We propose a simple technique to overcome this menace of warping. Materials and Methods: We present the data of 51 patients of rhinoplasty done using CCG with counterbalancing technique over a period of 4 years. Results: No evidence of warping was found in any patient up to a maximum follow-up period of 4 years. Conclusion: Counterbalancing is a useful technique to overcome the problem of warping. It gives liberty to utilize even unbalanced cartilage safely to provide desired shape and use the cartilage without any wastage. PMID:26424973

  10. Management of articular cartilage defects of the knee.

    PubMed

    Bedi, Asheesh; Feeley, Brian T; Williams, Riley J

    2010-04-01

    Articular cartilage has a poor intrinsic capacity for healing. The goal of surgical techniques to repair articular cartilage injuries is to achieve the regeneration of organized hyaline cartilage. Microfracture and other bone marrow stimulation techniques involve penetration of the subchondral plate in order to recruit mesenchymal stem cells into the chondral defect. The formation of a stable clot that fills the lesion is of paramount importance to achieve a successful outcome. Mosaicplasty is a viable option with which to address osteochondral lesions of the knee and offers the advantage of transplanting hyaline cartilage. However, limited graft availability and donor site morbidity are concerns. Transplantation of an osteochondral allograft consisting of intact, viable articular cartilage and its underlying subchondral bone offers the ability to address large osteochondral defects of the knee, including those involving an entire compartment. The primary theoretical advantage of autologous chondrocyte implantation is the development of hyaline-like cartilage rather than fibrocartilage in the defect, which presumably leads to better long-term outcomes and longevity of the healing tissue. Use of synthetic scaffolds is a potentially attractive alternative to traditional cartilage procedures as they are readily available and, unlike allogeneic tissue transplants, are associated with no risk of disease transmission. Their efficacy, however, has not been proven clinically.

  11. Real-time fluorescence imaging of the DNA damage repair response during mitosis.

    PubMed

    Miwa, Shinji; Yano, Shuya; Yamamoto, Mako; Matsumoto, Yasunori; Uehara, Fuminari; Hiroshima, Yukihiko; Toneri, Makoto; Murakami, Takashi; Kimura, Hiroaki; Hayashi, Katsuhiro; Yamamoto, Norio; Efimova, Elena V; Tsuchiya, Hiroyuki; Hoffman, Robert M

    2015-04-01

    The response to DNA damage during mitosis was visualized using real-time fluorescence imaging of focus formation by the DNA-damage repair (DDR) response protein 53BP1 linked to green fluorescent protein (GFP) (53BP1-GFP) in the MiaPaCa-2(Tet-On) pancreatic cancer cell line. To observe 53BP1-GFP foci during mitosis, MiaPaCa-2(Tet-On) 53BP1-GFP cells were imaged every 30 min by confocal microscopy. Time-lapse imaging demonstrated that 11.4 ± 2.1% of the mitotic MiaPaCa-2(Tet-On) 53BP1-GFP cells had increased focus formation over time. Non-mitotic cells did not have an increase in 53BP1-GFP focus formation over time. Some of the mitotic MiaPaCa-2(Tet-On) 53BP1-GFP cells with focus formation became apoptotic. The results of the present report suggest that DNA strand breaks occur during mitosis and undergo repair, which may cause some of the mitotic cells to enter apoptosis in a phenomenon possibly related to mitotic catastrophe.

  12. Mechanotransduction and cartilage integrity

    PubMed Central

    Leong, Daniel J.; Hardin, John A.; Cobelli, Neil J.; Sun, Hui B.

    2015-01-01

    Osteoarthritis (OA) is characterized by the breakdown of articular cartilage that is mediated in part by increased production of matrix metalloproteinases (MMPs) and aggrecanases (ADAMTS), enzymes that degrade components of the cartilage extracellular matrix. Efforts to design synthetic inhibitors of MMPs/ADAMTS have only led to limited clinical success. In addition to pharmacologic therapies, physiologic joint loading is widely recommended as a nonpharmacologic approach to improve joint function in osteoarthritis. Clinical trials report that moderate levels of exercise exert beneficial effects, such as improvements in pain and physical function. Experimental studies demonstrate that mechanical loading mitigates joint destruction through the downregulation of MMPs/ADAMTS. However, the molecular mechanisms underlying these effects of physiologic loading on arthritic joints are not well understood. We review here the recent progress on mechanotransduction in articular joints, highlighting the mediators and pathways in the maintenance of cartilage integrity, especially in the prevention of cartilage degradation in OA. PMID:22172037

  13. Altered function in cartilage derived mesenchymal stem cell leads to OA-related cartilage erosion

    PubMed Central

    Xia, Zenan; Ma, Pei; Wu, Nan; Su, Xinlin; Chen, Jun; Jiang, Chao; Liu, Sen; Chen, Weisheng; Ma, Bupeng; Yang, Xu; Ma, Yufen; Weng, Xisheng; Qiu, Guixing; Huang, Shishu; Wu, Zhihong

    2016-01-01

    A portion of osteoarthritis (OA) patients with total knee arthroplasty (TKA) had monocondylar destruction in medial femoral condyle, but healthy-appearant cartilage in lateral side. However, there is limited information concerning functional differences of cartilage derived mesenchymal stem cell (CMSC) between these two locations in the same donor and its possible role in the pathogenesis of OA. Cells isolated from the degraded cartilage in medial condyle and normal cartilage in lateral side from OA patients were identified with co-expressed markers CD105 and CD166 and confirmed as CMSCs by immunophenotype. The relative percentage, proliferation activity, multi-lineage differentiation potential and miRNA expression profile of CMSCs in two groups were compared by flow cytometry, CCK-8 assay, cytochemical staining, immunohistochemistry, real-time PCR and miRNA microarray analysis. Our study suggested that the percentage (10.61±6.97% vs. 18.44±9.97%, P<0.05) and proliferation rate (P<0.01) of CD105+/CD166+ CMSCs from the degraded cartilage were significantly reduced compared with those from the normal cartilage. CMSCs from the degraded cartilage also showed stronger osteogenic (P<0.05), weaker adipogenic (P<0.01), and comparable chondrogenic potential (P>0.05) during differentiation. MiR-31-5p and miR-424-5p were down regulated in CMSCs from the degraded cartilage. In conclusion, altered function such as reduced percentage and proliferation ability, as well as changes in differentiation profile of CMSC contributed to homeostasis imbalance, leading to OA-related cartilage erosion. Furthermore, regulatory networks of multiple miRNAs may be partially responsible for the dysfunction of CMSCs. PMID:27158337

  14. Use of Adult Stem Cells for Cartilage Tissue Engineering: Current Status and Future Developments

    PubMed Central

    Baugé, Catherine; Boumédiene, Karim

    2015-01-01

    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. So, in recent years, researchers and surgeons have been working hard to elaborate cartilage repair interventions for patients who suffer from cartilage damage. However, current methods do not perfectly restore hyaline cartilage and may lead to the apparition of fibro- or hypertrophic cartilage. In the next years, the development of new strategies using adult stem cells, in scaffolds, with supplementation of culture medium and/or culture in low oxygen tension should improve the quality of neoformed cartilage. Through these solutions, some of the latest technologies start to bring very promising results in repairing cartilage from traumatic injury or chondropathies. This review discusses the current knowledge about the use of adult stem cells in the context of cartilage tissue engineering and presents clinical trials in progress, as well as in the future, especially in the field of bioprinting stem cells. PMID:26246809

  15. Kartogenin-Incorporated Thermogel Supports Stem Cells for Significant Cartilage Regeneration.

    PubMed

    Li, Xuezhou; Ding, Jianxun; Zhang, Zhengzheng; Yang, Modi; Yu, Jiakuo; Wang, Jincheng; Chang, Fei; Chen, Xuesi

    2016-03-01

    Recently, cartilage tissue engineering (CTE) attracts increasing attention in cartilage defect repair. In this work, kartogenin (KGN), an emerging chondroinductive nonprotein small molecule, was incorporated into a thermogel of poly(L-lactide-co-glycolide)-poly(ethylene glycol)-poly(L-lactide-co-glycolide) (PLGA-PEG-PLGA) to fabricate an appropriate microenvironment of bone marrow mesenchymal stem cells (BMSCs) for effective cartilage regeneration. More integrative and smoother repaired articular surface, more abundant characteristic glycosaminoglycans (GAGs) and collagen II (COL II), and less degeneration of normal cartilage were obtained in the KGN and BMSCs coloaded thermogel group in vivo. In conclusion, the KGN-loaded PLGA-PEG-PLGA thermogel can be utilized as an alternative support for BMSCs to regenerate damaged cartilage in vivo. PMID:26844837

  16. Nanotechnology Biomimetic Cartilage Regenerative Scaffolds

    PubMed Central

    Sardinha, Jose Paulo; Myers, Simon

    2014-01-01

    Cartilage has a limited regenerative capacity. Faced with the clinical challenge of reconstruction of cartilage defects, the field of cartilage engineering has evolved. This article reviews current concepts and strategies in cartilage engineering with an emphasis on the application of nanotechnology in the production of biomimetic cartilage regenerative scaffolds. The structural architecture and composition of the cartilage extracellular matrix and the evolution of tissue engineering concepts and scaffold technology over the last two decades are outlined. Current advances in biomimetic techniques to produce nanoscaled fibrous scaffolds, together with innovative methods to improve scaffold biofunctionality with bioactive cues are highlighted. To date, the majority of research into cartilage regeneration has been focused on articular cartilage due to the high prevalence of large joint osteoarthritis in an increasingly aging population. Nevertheless, the principles and advances are applicable to cartilage engineering for plastic and reconstructive surgery. PMID:24883273

  17. Cartilage on the Move: Cartilage Lineage Tracing During Tadpole Metamorphosis

    PubMed Central

    Kerney, Ryan R.; Brittain, Alison L.; Hall, Brian K.; Buchholz, Daniel R.

    2012-01-01

    The reorganization of cranial cartilages during tadpole metamorphosis is a set of complex processes. The fates of larval cartilage-forming cells (chondrocytes) and sources of adult chondrocytes are largely unknown. Individual larval cranial cartilages may either degenerate or remodel, while many adult cartilages appear to form de novo during metamorphosis. Determining the extent to which adult chondrocytes/cartilages are derived from larval chondrocytes during metamorphosis requires new techniques in chondrocyte lineage tracing. We have developed two transgenic systems to label cartilage cells throughout the body with fluorescent proteins. One system strongly labels early tadpole cartilages only. The other system inducibly labels forming cartilages at any developmental stage. We examined cartilages of the skull (viscero- and neurocranium), and identified larval cartilages that either resorb or remodel into adult cartilages. Our data show that the adult otic capsules, tecti anterius and posterius, hyale, and portions of Meckel’s cartilage are derived from larval chondrocytes. Our data also suggest that most adult cartilages form de novo, though we cannot rule out the potential for extreme larval chondrocyte proliferation or de- and re-differentiation, which could dilute our fluorescent protein signal. The transgenic lineage tracing strategies developed here are the first examples of inducible, skeleton-specific, lineage tracing in Xenopus. PMID:23036161

  18. Chondrogenesis, chondrocyte differentiation, and articular cartilage metabolism in health and osteoarthritis.

    PubMed

    Goldring, Mary B

    2012-08-01

    Chondrogenesis occurs as a result of mesenchymal cell condensation and chondroprogenitor cell differentiation. Following chondrogenesis, the chondrocytes remain as resting cells to form the articular cartilage or undergo proliferation, terminal differentiation to chondrocyte hypertrophy, and apoptosis in a process termed endochondral ossification, whereby the hypertrophic cartilage is replaced by bone. Human adult articular cartilage is a complex tissue of matrix proteins that varies from superficial to deep layers and from loaded to unloaded zones. A major challenge to efforts to repair cartilage by stem cell-based and other tissue-engineering strategies is the inability of the resident chondrocytes to lay down a new matrix with the same properties as it had when it was formed during development. Thus, understanding and comparing the mechanisms of cartilage remodeling during development, osteoarthritis (OA), and aging may lead to more effective strategies for preventing cartilage damage and promoting repair. The pivotal proteinase that marks OA progression is matrix metalloproteinase 13 (MMP-13), the major type II collagen-degrading collagenase, which is regulated by both stress and inflammatory signals. We and other investigators have found that there are common mediators of these processes in human OA cartilage. We also observe temporal and spatial expression of these mediators in early through late stages of OA in mouse models and are analyzing the consequences of knockout or transgenic overexpression of critical genes. Since the chondrocytes in adult human cartilage are normally quiescent and maintain the matrix in a low turnover state, understanding how they undergo phenotypic modulation and promote matrix destruction and abnormal repair in OA may to lead to identification of critical targets for therapy to block cartilage damage and promote effective cartilage repair. PMID:22859926

  19. Tai Chi Improves Oxidative Stress Response and DNA Damage/Repair in Young Sedentary Females

    PubMed Central

    Huang, Xing-Yu; Eungpinichpong, Wichai; Silsirivanit, Atit; Nakmareong, Saowanee; Wu, Xiu-Hua

    2014-01-01

    [Purpose] This study was to examine the effects of 12 weeks of Tai Chi (TC) exercise on antioxidant capacity, and DNA damage/repair in young females who did not perform regular physical exercise. [Subjects and Methods] Ten female students from a Chinese university voluntarily participated in this program. All of them practiced the 24-form simplified Tai Chi, 5 times weekly, for 12 weeks. Plasma levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA), glutathione (GSH), hydroxyl radical inhibiting capacity (OH·-IC), 8-hydroxy-2’-deoxyguanosine (8-OHdG), and 8-oxoguanine DNA glycosylase (OGG1) were measured at 0, 8, and 12 weeks. Heart rate (HR) was monitored during the last set of the training session at 4, 8, and 12 weeks. [Results] Plasma SOD and OH·-IC levels were increased at 8 and 12 weeks compared to the baseline (0 weeks). Gpx and GSH levels did not change significantly throughout the study period. The plasma MDA level was decreased significantly at 8 weeks but not at 12 weeks compared to the baseline value. While the plasma 8-OHdG level did not change throughout the study period, the plasma OGG1 level was significantly increased at 8 and 12 weeks compared to the baseline value. [Conclusion] TC practice for 12 weeks efficiently improved the oxidative stress response in young females who did not perform regular physical exercise. The TC exercise also increased the DNA repairing capacity. PMID:25013276

  20. Increased Production of Clusterin in Biopsies of Repair Tissue following Autologous Chondrocyte Implantation

    PubMed Central

    Malda, Jos; Richardson, James B.; Roberts, Sally

    2013-01-01

    Objective. To characterize the immunolocalization of clusterin in the repair cartilage of patients having undergone autologous chondrocyte implantation (ACI) and evaluate correlation to clinical outcome. Design. Full-depth core biopsies of repair tissue were obtained from 38 patients who had undergone ACI at an average of 18 ± 13 months previously (range 8-67 months). The biopsies were snap frozen, cryosectioned, and clusterin production immunolocalized using a specific monoclonal clusterin antibody and compared with normal and osteoarthritic cartilage. Clinical outcome was assessed from patients preoperatively, at the time of biopsy, and annually postoperatively. Results. Intensity of immunostaining for clusterin decreased with age in healthy cartilage tissue. Clusterin was detected to a variable degree in 37 of the 38 ACI cartilage biopsies, in single and clustered chondrocytes, in the pericellular capsule and the cartilage extracellular matrix, as well as the osteocytes and osteoid within the bone. Chondrocytes in hyaline repair tissue were significantly more immunopositive than those in fibrocartilage repair tissue. Clinical outcome improved significantly post-ACI, but did not correlate with the presence of clusterin in the repair tissue. Conclusions. These results demonstrate the presence of clusterin in actively repairing human cartilage and indicate a different distribution of clusterin in this tissue compared to normal cartilage. Variability in clusterin staining in the repair tissue could indicate different states of chondrogenic differentiation. The clinical significance of clusterin within repair tissue is difficult to assess, although the ideal functioning repair tissue morphology should resemble that of healthy adult cartilage. PMID:26069669

  1. Extracellular-matrix-based and Arg-Gly-Asp-modified photopolymerizing hydrogels for cartilage tissue engineering.

    PubMed

    Kim, Hwan D; Heo, Jiseung; Hwang, Yongsung; Kwak, Seon-Yeong; Park, Ok Kyu; Kim, Hyunbum; Varghese, Shyni; Hwang, Nathaniel S

    2015-02-01

    Articular cartilage damage is a persistent and increasing problem with the aging population. Strategies to achieve complete repair or functional restoration remain a challenge. Photopolymerizing-based hydrogels have long received an attention in the cartilage tissue engineering, due to their unique bioactivities, flexible method of synthesis, range of constituents, and desirable physical characteristics. In the present study, we have introduced unique bioactivity within the photopolymerizing-based hydrogels by copolymerizing polyethylene glycol (PEG) macromers with methacrylated extracellular matrix (ECM) molecules (hyaluronic acid and chondroitin sulfate [CS]) and integrin binding peptides (RGD peptide). Results indicate that cellular morphology, as observed by the actin cytoskeleton structures, was strongly dependent on the type of ECM component as well as the presence of integrin binding moieties. Further, CS-based hydrogel with integrin binding RGD moieties increased the lubricin (or known as superficial zone protein [SZP]) gene expression of the encapsulated chondrocytes. Additionally, CS-based hydrogel displayed cell-responsive degradation and resulted in increased DNA, GAG, and collagen accumulation compared with other hydrogels. This study demonstrates that integrin-mediated interactions within CS microenvironment provide an optimal hydrogel scaffold for cartilage tissue engineering application.

  2. Extracellular-matrix-based and Arg-Gly-Asp-modified photopolymerizing hydrogels for cartilage tissue engineering.

    PubMed

    Kim, Hwan D; Heo, Jiseung; Hwang, Yongsung; Kwak, Seon-Yeong; Park, Ok Kyu; Kim, Hyunbum; Varghese, Shyni; Hwang, Nathaniel S

    2015-02-01

    Articular cartilage damage is a persistent and increasing problem with the aging population. Strategies to achieve complete repair or functional restoration remain a challenge. Photopolymerizing-based hydrogels have long received an attention in the cartilage tissue engineering, due to their unique bioactivities, flexible method of synthesis, range of constituents, and desirable physical characteristics. In the present study, we have introduced unique bioactivity within the photopolymerizing-based hydrogels by copolymerizing polyethylene glycol (PEG) macromers with methacrylated extracellular matrix (ECM) molecules (hyaluronic acid and chondroitin sulfate [CS]) and integrin binding peptides (RGD peptide). Results indicate that cellular morphology, as observed by the actin cytoskeleton structures, was strongly dependent on the type of ECM component as well as the presence of integrin binding moieties. Further, CS-based hydrogel with integrin binding RGD moieties increased the lubricin (or known as superficial zone protein [SZP]) gene expression of the encapsulated chondrocytes. Additionally, CS-based hydrogel displayed cell-responsive degradation and resulted in increased DNA, GAG, and collagen accumulation compared with other hydrogels. This study demonstrates that integrin-mediated interactions within CS microenvironment provide an optimal hydrogel scaffold for cartilage tissue engineering application. PMID:25266634

  3. sb203580 preconditioning recharges matrix-expanded human adult stem cells for chondrogenesis in an inflammatory environment – a feasible approach for autologous stem cell based osteoarthritic cartilage repair

    PubMed Central

    Zhang, Ying; Pizzute, Tyler; Li, Jingting; He, Fan; Pei, Ming

    2015-01-01

    Autologous stem cells are a promising cell source for cartilage regeneration; however, cell replicative senescence and joint posttraumatic inflammation provide challenges to bring this treatment modality to fruition. In this study, we hypothesized that preconditioning with p38 MAPK inhibitor (sb203580) would recharge decellularized extracellular matrix (dECM) expanded human synovium-derived stem cell (hSDSC) chondrogenesis in an inflammatory environment. We found that preconditioning with sb203580 greatly enhanced dECM expanded hSDSC proliferation and chondrogenic potential while supplementation with sb203580 in an induction medium dramatically retarded hSDSC chondrogenic differentiation, even for dECM expanded cells. We also found that sb203580 preconditioning enhanced matrix-expanded hSDSC chondrogenic capacity even in an interleukin-1 (IL-1) induced inflammatory environment. Non-detectable expression of HLA-DR in the hSDSCs grown on allogeneic dECM indicates the feasibility of commercial preparation of these dECMs from healthy, young donors for patients who need autologous transplantation. Our study indicated that p38 MAPK inhibitor has a distinctive priming effect on dECM mediated stem cell cartilage regeneration. Combined rejuvenation with sb203580 and dECM expansion can precondition hSDSCs’ resurfacing capacity for osteoarthritic patients with cartilage defects. PMID:26122165

  4. Effect of passive motion on articular cartilage in rat osteoarthritis.

    PubMed

    Qian, Jie; Liang, Jun; Wang, Yubin; Wang, Huifang

    2014-08-01

    fibers when compared with the control group, but not when compared with the three-week experimental group. Therefore, proper passive motion can repair and improve the metabolism of chondrocytes and delay the degenerative progress of articular cartilage in OA caused by knee fracture. However, for middle-stage OA, passive motion exhibits no significant repairing effect on the articular cartilage. This therapy increases the levels of proteoglycans and collagen fibers by reducing their decomposition, thereby improving the strength of the articular ligament and the stability of articulation. PMID:25009586

  5. The chitinase 3-like protein human cartilage glycoprotein 39 inhibits cellular responses to the inflammatory cytokines interleukin-1 and tumour necrosis factor-alpha.

    PubMed Central

    Ling, Hua; Recklies, Anneliese D

    2004-01-01

    Expression of the chitinase 3-like protein HC-gp39 (human cartilage glycoprotein 39) is associated with conditions of increased matrix turnover and tissue remodelling. High levels of this protein have been found in sera and synovial fluids of patients with inflammatory and degenerative arthritis. In order to assess the role of HC-gp39 in matrix degradation induced by inflammatory cytokines, we have examined its effect on the responses of connective tissue cells to TNF-alpha (tumour necrosis factor-alpha) and IL-1 (interleukin-1) with respect to activation of signalling pathways and production of MMPs (matrix metalloproteases) and chemokines. Stimulation of human skin fibroblasts or articular chondrocytes with IL-1 or TNF-alpha in the presence of HC-gp39 resulted in a marked reduction of both p38 mitogen-activated protein kinase and stress-activated protein kinase/Jun N-terminal kinase phosphorylation, whereas nuclear translocation of nuclear factor kappaB proceeded unimpeded. HC-gp39 suppressed the cytokine-induced secretion of MMP1, MMP3 and MMP13, as well as secretion of the chemokine IL-8. The suppressive effects of HC-gp39 were dependent on phosphoinositide 3-kinase activity, and treatment of cells with HC-gp39 resulted in AKT-mediated serine/threonine phosphorylation of apoptosis signal-regulating kinase 1. This process could therefore be responsible for the down-regulation of cytokine signalling by HC-gp39. These results suggest a physiological role for HC-gp39 in limiting the catabolic effects of inflammatory cytokines. PMID:15015934

  6. Comprehensive Genome-Wide Transcriptomic Analysis of Immature Articular Cartilage following Ischemic Osteonecrosis of the Femoral Head in Piglets

    PubMed Central

    Adapala, Naga Suresh; Kim, Harry K. W.

    2016-01-01

    Objective Ischemic osteonecrosis of the femoral head (ONFH) in piglets results in an ischemic injury to the immature articular cartilage. The molecular changes in the articular cartilage in response to ONFH have not been investigated using a transcriptomic approach. The purpose of this study was to perform a genome-wide transcriptomic analysis to identify genes that are upregulated in the immature articular cartilage following ONFH. Methods ONFH was induced in the right femoral head of 6-week old piglets. The unoperated femoral head was used as the normal control. At 24 hours (acute ischemic-hypoxic injury), 2 weeks (avascular necrosis in the femoral head) and 4 weeks (early repair) after surgery (n = 4 piglets/time point), RNA was isolated from the articular cartilage of the femoral head. A microarray analysis was performed using Affymetrix Porcine GeneChip Array. An enrichment analysis and functional clustering of the genes upregulated due to ONFH were performed using DAVID and STRING software, respectively. The increased expression of selected genes was confirmed by a real-time qRTPCR analysis. Results Induction of ONFH resulted in the upregulation of 383 genes at 24 hours, 122 genes at 2 weeks and 124 genes at 4 weeks compared to the normal controls. At 24 hours, the genes involved in oxidoreductive, cell-survival, and angiogenic responses were significantly enriched among the upregulated genes. These genes were involved in HIF-1, PI3K-Akt, and MAPK signaling pathways. At 2 weeks, secretory and signaling proteins involved in angiogenic and inflammatory responses, PI3K-Akt and matrix-remodeling pathways were significantly enriched. At 4 weeks, genes that represent inflammatory cytokines and chemokine signaling pathways were significantly enriched. Several index genes (genes that are upregulated at more than one time point following ONFH and are known to be important in various biological processes) including HIF-1A, VEGFA, IL-6, IL6R, IL-8, CCL2, FGF2, TGFB2

  7. Functions of FUS/TLS From DNA Repair to Stress Response: Implications for ALS

    PubMed Central

    Sama, Reddy Ranjith Kumar; Ward, Catherine L.

    2014-01-01

    Fused in sarcoma/translocated in liposarcoma (FUS/TLS or FUS) is a multifunctional DNA-/RNA-binding protein that is involved in a variety of cellular functions including transcription, protein translation, RNA splicing, and transport. FUS was initially identified as a fusion oncoprotein, and thus, the early literature focused on the role of FUS in cancer. With the recent discoveries revealing the role of FUS in neurodegenerative diseases, namely amyotrophic lateral sclerosis and frontotemporal lobar degeneration, there has been a renewed interest in elucidating the normal functions of FUS. It is not clear which, if any, endogenous functions of FUS are involved in disease pathogenesis. Here, we review what is currently known regarding the normal functions of FUS with an emphasis on DNA damage repair, RNA processing, and cellular stress response. Further, we discuss how ALS-causing mutations can potentially alter the role of FUS in these pathways, thereby contributing to disease pathogenesis. PMID:25289647

  8. The Effect of Steroid Therapy on Postoperative Inflammatory Response after Endovascular Abdominal Aortic Aneurysm Repair

    PubMed Central

    Aoki, Atsushi; Omoto, Tadashi; Iizuka, Hirofumi; Kawaura, Hiroyuki

    2016-01-01

    Objectives: Unexpected systemic inflammatory response with high fever and increase in C-reactive protein (CRP) occurred frequently after endovascular abdominal aortic aneurysm repair (EVAR). This excessive inflammatory response affects the postoperative course. We evaluated the effects of steroid on the postoperative inflammatory response after EVAR. Methods: Steroid therapy, intravenous infusion of methylprednisolone 1000 mg just after the anesthesia induction, was started since December 2012. After induction of the steroid therapy, 25 patients underwent EVAR with steroid therapy (Group S). These patients were compared with the 65 patients who underwent EVAR without steroid therapy (Group C) in white blood cell count (WBC), CRP and maximum body temperature (BT) on postoperative day 1–5. Results: There was no significant difference in age, female gender, operation time, maximum aneurysm diameter between the two groups. There was no postoperative infective complication in the both groups. WBC did not differ between the two groups; however, CRP was significantly suppressed in Group S than in Group C on POD 1, 3 and 5. Also BT was significantly lower in Group S than Group C on POD 1, 2 and 3. Conclusions: Steroid pretreatment before implantation of the stent graft reduces the early postoperative inflammatory response after EVAR, without increasing postoperative infection. (This is a translation of Jpn J Vasc Surg 2015; 24: 861–865.)

  9. Extracellular sulfatases support cartilage homeostasis by regulating BMP and FGF signaling pathways

    PubMed Central

    Otsuki, Shuhei; Hanson, Sarah R.; Miyaki, Shigeru; Grogan, Shawn P.; Kinoshita, Mitsuo; Asahara, Hiroshi; Wong, Chi-Huey; Lotz, Martin K.

    2010-01-01

    The balance between anabolic and catabolic signaling pathways is critical in maintaining cartilage homeostasis and its disturbance contributes to joint diseases such as osteoarthritis (OA). A unique mechanism that modulates the activity of cell signaling pathways is controlled by extracellular heparan endosulfatases Sulf-1 and Sulf-2 (Sulfs) that are overexpressed in OA cartilage. This study addressed the role of Sulfs in cartilage homeostasis and in regulating bone morphogenetic protein (BMP)/Smad and fibroblast growth factor (FGF)/Erk signaling in articular cartilage. Spontaneous cartilage degeneration and surgically induced OA were significantly more severe in Sulf-1−/− and Sulf-2−/− mice compared with wild-type mice. MMP-13, ADAMTS-5, and the BMP antagonist noggin were elevated whereas col2a1 and aggrecan were reduced in cartilage and chondrocytes from Sulf−/− mice. Articular cartilage and cultured chondrocytes from Sulf−/− mice showed reduced Smad1 protein expression and Smad1/5 phosphorylation, whereas Erk1/2 phosphorylation was increased. In human chondrocytes, Sulfs siRNA reduced Smad phosphorylation but enhanced FGF-2-induced Erk1/2 signaling. These findings suggest that Sulfs simultaneously enhance BMP but inhibit FGF signaling in chondrocytes and maintain cartilage homeostasis. Approaches to correct abnormal Sulf expression have the potential to protect against cartilage degradation and promote cartilage repair in OA. PMID:20479257

  10. Mechanical testing of hydrogels in cartilage tissue engineering: beyond the compressive modulus.

    PubMed

    Xiao, Yinghua; Friis, Elizabeth A; Gehrke, Stevin H; Detamore, Michael S

    2013-10-01

    Injuries to articular cartilage result in significant pain to patients and high medical costs. Unfortunately, cartilage repair strategies have been notoriously unreliable and/or complex. Biomaterial-based tissue-engineering strategies offer great promise, including the use of hydrogels to regenerate articular cartilage. Mechanical integrity is arguably the most important functional outcome of engineered cartilage, although mechanical testing of hydrogel-based constructs to date has focused primarily on deformation rather than failure properties. In addition to deformation testing, as the field of cartilage tissue engineering matures, this community will benefit from the addition of mechanical failure testing to outcome analyses, given the crucial clinical importance of the success of engineered constructs. However, there is a tremendous disparity in the methods used to evaluate mechanical failure of hydrogels and articular cartilage. In an effort to bridge the gap in mechanical testing methods of articular cartilage and hydrogels in cartilage regeneration, this review classifies the different toughness measurements for each. The urgency for identifying the common ground between these two disparate fields is high, as mechanical failure is ready to stand alongside stiffness as a functional design requirement. In comparing toughness measurement methods between hydrogels and cartilage, we recommend that the best option for evaluating mechanical failure of hydrogel-based constructs for cartilage tissue engineering may be tensile testing based on the single edge notch test, in part because specimen preparation is more straightforward and a related American Society for Testing and Materials (ASTM) standard can be adopted in a fracture mechanics context.

  11. Role of solar conditioning in DNA repair response and survival of human epidermal keratinocytes following UV irradiation

    SciTech Connect

    Liu, S.C.; Meagher, K.; Hanawalt, P.C.

    1985-08-01

    The authors have investigated the cumulative effects of sunlight exposure upon the excision-repair of UV radiation damage to DNA in epidermal keratinocytes from human donors of different ages as well as the possible effect on DNA repair of periodic conditioning of the cultured keratinocytes with sublethal UV radiation exposures. The authors have also compared the growth properties of UV-irradiated keratinocytes derived from habitually sun-exposed and nonexposed areas from the bodies of young and aged donors. DNA repair replication in keratinocytes from habitually sun-exposed facial skin and the less sun-exposed abdominal skin of middle-aged adults was found to be similar, with respect to both the UV dose response and the time course of repair after 20 J/m2, 254 nm. Growth and survival (after exposure up to 50 J/m2, 254 nm) were greater for keratinocytes from protected areas of the upper arm of young donors (under 18 years) than for cells from their own sun-exposed areas. Growth and survival were markedly reduced for all keratinocyte cultures from aged donors, especially those cultures developed from sun-exposed areas. Nevertheless, the DNA repair response to UV radiation was similar in all cases. The evident uncoupling of UV sensitivity from DNA repair capacity remains to be understood. These studies confirm that the cumulative effect of sunlight exposure indeed contributes to some skin aging processes. However, the authors have found no indication that an overall reduction in capacity for excision-repair of UV photoproducts in keratinocyte DNA accompanies senescence in human skin.

  12. Anti-cartilage antibody.

    PubMed

    Greenbury, C L; Skingle, J

    1979-08-01

    Antibody to cartilage has been demonstrated by indirect immunofluorescence on rat trachea in the serum of about 3% of 1126 patients with rheumatoid arthritis. Titres ranged from 1:20 to 1:640. The antibody was not found in 284 patients with primary or secondary osteoarthritis or in 1825 blood donors, nor, with the exception of two weak reactors, in 1314 paraplegic patients. In most cases the antibody appears to be specific for native type II collagen. Using this as an antigen in a haemagglutination test 94% of anti-cartilage sera were positive, whereas among 100 rheumatoid control sera there were only three weak positives. More than 80% of patients with antibody had some erosion of articular cartilage, but there was no correlation with age, sex, duration of disease, nor any recognisable clinical event or change.

  13. Anti-cartilage antibody.

    PubMed Central

    Greenbury, C L; Skingle, J

    1979-01-01

    Antibody to cartilage has been demonstrated by indirect immunofluorescence on rat trachea in the serum of about 3% of 1126 patients with rheumatoid arthritis. Titres ranged from 1:20 to 1:640. The antibody was not found in 284 patients with primary or secondary osteoarthritis or in 1825 blood donors, nor, with the exception of two weak reactors, in 1314 paraplegic patients. In most cases the antibody appears to be specific for native type II collagen. Using this as an antigen in a haemagglutination test 94% of anti-cartilage sera were positive, whereas among 100 rheumatoid control sera there were only three weak positives. More than 80% of patients with antibody had some erosion of articular cartilage, but there was no correlation with age, sex, duration of disease, nor any recognisable clinical event or change. Images Fig. 1 PMID:389957

  14. Cartilage (Bovine and Shark) (PDQ)

    MedlinePlus

    ... and use of cartilage as a complementary or alternative treatment for cancer? Cartilage from cows (bovine cartilage) and sharks has ... of CAM therapies originally considered to be purely alternative approaches are finding a place in cancer treatment—not as cures, but as complementary therapies that ...

  15. The surface of articular cartilage contains a progenitor cell population.

    PubMed

    Dowthwaite, Gary P; Bishop, Joanna C; Redman, Samantha N; Khan, Ilyas M; Rooney, Paul; Evans, Darrell J R; Haughton, Laura; Bayram, Zubeyde; Boyer, Sam; Thomson, Brian; Wolfe, Michael S; Archer, Charles W

    2004-02-29

    It is becoming increasingly apparent that articular cartilage growth is achieved by apposition from the articular surface. For such a mechanism to occur, a population of stem/progenitor cells must reside within the articular cartilage to provide transit amplifying progeny for growth. Here, we report on the isolation of an articular cartilage progenitor cell from the surface zone of articular cartilage using differential adhesion to fibronectin. This population of cells exhibits high affinity for fibronectin, possesses a high colony-forming efficiency and expresses the cell fate selector gene Notch 1. Inhibition of Notch signalling abolishes colony forming ability whilst activated Notch rescues this inhibition. The progenitor population also exhibits phenotypic plasticity in its differentiation pathway in an embryonic chick tracking system, such that chondroprogenitors can engraft into a variety of connective tissue types including bone, tendon and perimysium. The identification of a chondrocyte subpopulation with progenitor-like characteristics will allow for advances in our understanding of both cartilage growth and maintenance as well as provide novel solutions to articular cartilage repair. PMID:14762107

  16. Expression of Superficial Zone Protein in Mandibular Condyle Cartilage

    PubMed Central

    Ohno, S; Schmid, T; Tanne, Y; Kamiya, T; Honda, K; Ohno-Nakahara, M; Swentko, N; Desai, T A; Tanne, K; Knudson, CB; Knudson, W

    2011-01-01

    Objective Superficial zone protein (SZP) has been shown to function in the boundary lubrication of articular cartilages of the extremities. However, the expression of SZP has not been clarified in mandibular cartilage which is a tissue that includes a thick fibrous layer on the surface. This study was conducted to clarify the distribution of SZP on the mandibular condyle and the regulatory effects of humoral factors on the expression in both explants and fibroblasts derived from mandibular condyle. Methods The distribution of SZP was determined in bovine mandibular condyle cartilage, and the effects of IL-1β and TGF-β on SZP expression were examined in condyle explants and, fibroblasts derived from the fibrous zone of condyle cartilage. Results SZP was highly distributed in the superficial zone of intact condyle cartilage. The SZP expression was up-regulated by TGF-β in both explants and cultured fibroblasts, whereas the expression was slightly down-regulated by IL-1β. A significant increase in accumulation of SZP protein was also observed in the culture medium of the fibroblasts treated with TGF-β. Conclusions These results suggest that SZP plays an important role in boundary lubrication of mandible condylar cartilage, is synthesized locally within the condyle itself and, exhibits differential regulation by cell mediators relevant to mandibular condyle repairing and pathologies. PMID:16563813

  17. The bacterial DNA repair protein Mfd confers resistance to the host nitrogen immune response.

    PubMed

    Guillemet, Elisabeth; Leréec, Alain; Tran, Seav-Ly; Royer, Corinne; Barbosa, Isabelle; Sansonetti, Philippe; Lereclus, Didier; Ramarao, Nalini

    2016-01-01

    Production of reactive nitrogen species (NO) is a key step in the immune response following infections. NO induces lesions to bacterial DNA, thus limiting bacterial growth within hosts. Using two pathogenic bacteria, Bacillus cereus and Shigella flexneri, we show that the DNA-repair protein Mfd (Mutation-Frequency-Decline) is required for bacterial resistance to the host-NO-response. In both species, a mutant deficient for mfd does not survive to NO, produced in vitro or by phagocytic cells. In vivo, the ∆mfd mutant is avirulent and unable to survive the NO-stress. Moreover, NO induces DNA-double-strand-breaks and point mutations in the Δmfd mutant. In overall, these observations demonstrate that NO damages bacterial DNA and that Mfd is required to maintain bacterial genomic integrity. This unexpected discovery reveals that Mfd, a typical housekeeping gene, turns out to be a true virulence factor allowing survival and growth of the pathogen in its host, due to its capacity to protect the bacterium against NO, a key molecule of the innate immune defense. As Mfd is widely conserved in the bacterial kingdom, these data highlight a mechanism that may be used by a large spectrum of bacteria to overcome the host immune response and especially the mutagenic properties of NO.

  18. The bacterial DNA repair protein Mfd confers resistance to the host nitrogen immune response.

    PubMed

    Guillemet, Elisabeth; Leréec, Alain; Tran, Seav-Ly; Royer, Corinne; Barbosa, Isabelle; Sansonetti, Philippe; Lereclus, Didier; Ramarao, Nalini

    2016-01-01

    Production of reactive nitrogen species (NO) is a key step in the immune response following infections. NO induces lesions to bacterial DNA, thus limiting bacterial growth within hosts. Using two pathogenic bacteria, Bacillus cereus and Shigella flexneri, we show that the DNA-repair protein Mfd (Mutation-Frequency-Decline) is required for bacterial resistance to the host-NO-response. In both species, a mutant deficient for mfd does not survive to NO, produced in vitro or by phagocytic cells. In vivo, the ∆mfd mutant is avirulent and unable to survive the NO-stress. Moreover, NO induces DNA-double-strand-breaks and point mutations in the Δmfd mutant. In overall, these observations demonstrate that NO damages bacterial DNA and that Mfd is required to maintain bacterial genomic integrity. This unexpected discovery reveals that Mfd, a typical housekeeping gene, turns out to be a true virulence factor allowing survival and growth of the pathogen in its host, due to its capacity to protect the bacterium against NO, a key molecule of the innate immune defense. As Mfd is widely conserved in the bacterial kingdom, these data highlight a mechanism that may be used by a large spectrum of bacteria to overcome the host immune response and especially the mutagenic properties of NO. PMID:27435260

  19. The bacterial DNA repair protein Mfd confers resistance to the host nitrogen immune response

    PubMed Central

    Guillemet, Elisabeth; Leréec, Alain; Tran, Seav-Ly; Royer, Corinne; Barbosa, Isabelle; Sansonetti, Philippe; Lereclus, Didier; Ramarao, Nalini

    2016-01-01

    Production of reactive nitrogen species (NO) is a key step in the immune response following infections. NO induces lesions to bacterial DNA, thus limiting bacterial growth within hosts. Using two pathogenic bacteria, Bacillus cereus and Shigella flexneri, we show that the DNA-repair protein Mfd (Mutation-Frequency-Decline) is required for bacterial resistance to the host-NO-response. In both species, a mutant deficient for mfd does not survive to NO, produced in vitro or by phagocytic cells. In vivo, the ∆mfd mutant is avirulent and unable to survive the NO-stress. Moreover, NO induces DNA-double-strand-breaks and point mutations in the Δmfd mutant. In overall, these observations demonstrate that NO damages bacterial DNA and that Mfd is required to maintain bacterial genomic integrity. This unexpected discovery reveals that Mfd, a typical housekeeping gene, turns out to be a true virulence factor allowing survival and growth of the pathogen in its host, due to its capacity to protect the bacterium against NO, a key molecule of the innate immune defense. As Mfd is widely conserved in the bacterial kingdom, these data highlight a mechanism that may be used by a large spectrum of bacteria to overcome the host immune response and especially the mutagenic properties of NO. PMID:27435260

  20. Interleukin-1 beta and tumor necrosis factor alpha inhibit migration activity of chondrogenic progenitor cells from non-fibrillated osteoarthritic cartilage

    PubMed Central

    2013-01-01

    Introduction The repair capability of traumatized articular cartilage is highly limited so that joint injuries often lead to osteoarthritis. Migratory chondrogenic progenitor cells (CPC) might represent a target cell population for in situ regeneration. This study aims to clarify, whether 1) CPC are present in regions of macroscopically intact cartilage from human osteoarthritic joints, 2) CPC migration is stimulated by single growth factors and the cocktail of factors released from traumatized cartilage and 3) CPC migration is influenced by cytokines present in traumatized joints. Methods We characterized the cells growing out from macroscopically intact human osteoarthritic cartilage using a panel of positive and negative surface markers and analyzed their differentiation capacity. The migratory response to platelet-derived growth factor (PDGF)-BB, insulin-like growth factor 1 (IGF-1), supernatants obtained from in vitro traumatized cartilage and interleukin-1 beta (IL-1β) as well as tumor necrosis factor alpha (TNF-α) were tested with a modified Boyden chamber assay. The influence of IL-1β and TNF-α was additionally examined by scratch assays and outgrowth experiments. Results A comparison of 25 quadruplicate marker combinations in CPC and bone-marrow derived mesenchymal stromal cells showed a similar expression profile. CPC cultures had the potential for adipogenic, osteogenic and chondrogenic differentiation. PDGF-BB and IGF-1, such as the supernatant from traumatized cartilage, induced a significant site-directed migratory response. IL-1β and TNF-α significantly reduced basal cell migration and abrogated the stimulative effect of the growth factors and the trauma supernatant. Both cytokines also inhibited cell migration in the scratch assay and primary outgrowth of CPC from cartilage tissue. In contrast, the cytokine IL-6, which is present in trauma supernatant, did not affect growth factor induced migration of CPC. Conclusion These results indicate

  1. A comparison of healthy human and swine articular cartilage dynamic indentation mechanics.

    PubMed

    Ronken, S; Arnold, M P; Ardura García, H; Jeger, A; Daniels, A U; Wirz, D

    2012-05-01

    Articular cartilage is a multicomponent, poroviscoelastic tissue with nonlinear mechanical properties vital to its function. A consequent goal of repair or replacement of injured cartilage is to achieve mechanical properties in the repair tissue similar to healthy native cartilage. Since fresh healthy human articular cartilage (HC) is not readily available, we tested whether swine cartilage (SC) could serve as a suitable substitute for mechanical comparisons. To a first approximation, cartilage tissue and surgical substitutes can be evaluated mechanically as viscoelastic materials. Stiffness measurements (dynamic modulus, loss angle) are vital to function and are also a non-destructive means of evaluation. Since viscoelastic material stiffness is strongly strain rate dependent, stiffness was tested under different loading conditions related to function. Stiffness of healthy HC and SC specimens was determined and compared using two non-destructive, mm-scale indentation test modes: fast impact and slow sinusoidal deformation. Deformation resistance (dynamic modulus) and energy handling (loss angle) were determined. For equivalent anatomic locations, there was no difference in dynamic modulus. However, the HC loss angle was ~35% lower in fast impact and ~12% higher in slow sinusoidal mode. Differences seem attributable to age (young SC, older HC) but also to species anatomy and biology. Test mode-related differences in human-swine loss angle support use of multiple function-related test modes. Keeping loss angle differences in mind, swine specimens could serve as a standard of comparison for mechanical evaluation of e.g. engineered cartilage or synthetic repair materials.

  2. A hormone-DNA repair circuit governs the response to genotoxic insult

    PubMed Central

    Goodwin, Jonathan F.; Schiewer, Matthew J.; Dean, Jeffry L.; Schrecengost, Randy S.; de Leeuw, Renee; Han, Sumin; Ma, Teng; Den, Robert B.; Dicker, Adam P.; Feng, Felix Y.; Knudsen, Karen E.

    2013-01-01

    Alterations in DNA repair promote tumor development, but the impact on tumor progression is poorly understood. Here, discovery of a biochemical circuit linking hormone signaling to DNA repair and therapeutic resistance is reported. Findings demonstrate that androgen receptor (AR) activity is induced by DNA damage, and promotes expression and activation of a gene expression program governing DNA repair. Subsequent investigation revealed that activated AR promotes resolution of double-strand breaks and resistance to DNA damage both in vitro and in vivo. Mechanistically, DNAPKcs was identified as a key target of AR after damage, controlling AR-mediated DNA repair and cell survival after genotoxic insult. Finally, DNAPKcs was shown to potentiate AR function, consistent with a dual role in both DNA repair and transcriptional regulation. Combined, these studies identify the AR-DNAPKcs circuit as a major effector of DNA repair and therapeutic resistance, and establish a new node for therapeutic intervention in advanced disease. PMID:24027197

  3. Biodegradable CSMA/PECA/Graphene Porous Hybrid Scaffold for Cartilage Tissue Engineering.

    PubMed

    Liao, JinFeng; Qu, Ying; Chu, BingYang; Zhang, XiaoNing; Qian, ZhiYong

    2015-01-01

    Owing to the limited repair capacity of articular cartilage, it is essential to develop tissue-engineered cartilage for patients suffering from joint disease and trauma. Herein, we prepared a novel hybrid scaffold composed of methacrylated chondroitin sulfate (CSMA), poly(ethylene glycol) methyl ether-ε-caprolactone-acryloyl chloride (MPEG-PCL-AC, PECA was used as abbreviation for MPEG-PCL-AC) and graphene oxide (GO) and evaluated its potential application in cartilage tissue engineering. To mimic the natural extracellular matrix (ECM) of cartilage, the scaffold had an adequate pore size, porosity, swelling ability, compression modulus and conductivity. Cartilage cells contacted with the scaffold remained viable and showed growth potential. Furthermore, CSMA/PECA/GO scaffold was biocompatible and had a favorable degradation rate. In the cartilage tissue repair of rabbit, Micro-CT and histology observation showed the group of CSMA/PECA/GO scaffold with cellular supplementation had better chondrocyte morphology, integration, continuous subchondral bone, and much thicker newly formed cartilage compared with scaffold group and control group. Our results show that the CSMA/PECA/GO hybrid porous scaffold can be applied in articular cartilage tissue engineering and may have great potential to in other types of tissue engineering applications. PMID:25961959

  4. Biodegradable CSMA/PECA/Graphene Porous Hybrid Scaffold for Cartilage Tissue Engineering

    PubMed Central

    Liao, JinFeng; Qu, Ying; Chu, BingYang; Zhang, XiaoNing; Qian, ZhiYong

    2015-01-01

    Owing to the limited repair capacity of articular cartilage, it is essential to develop tissue-engineered cartilage for patients suffering from joint disease and trauma. Herein, we prepared a novel hybrid scaffold composed of methacrylated chondroitin sulfate (CSMA), poly(ethylene glycol) methyl ether-ε-caprolactone-acryloyl chloride (MPEG-PCL-AC, PECA was used as abbreviation for MPEG-PCL-AC) and graphene oxide (GO) and evaluated its potential application in cartilage tissue engineering. To mimic the natural extracellular matrix (ECM) of cartilage, the scaffold had an adequate pore size, porosity, swelling ability, compression modulus and conductivity. Cartilage cells contacted with the scaffold remained viable and showed growth potential. Furthermore, CSMA/PECA/GO scaffold was biocompatible and had a favorable degradation rate. In the cartilage tissue repair of rabbit, Micro-CT and histology observation showed the group of CSMA/PECA/GO scaffold with cellular supplementation had better chondrocyte morphology, integration, continuous subchondral bone, and much thicker newly formed cartilage compared with scaffold group and control group. Our results show that the CSMA/PECA/GO hybrid porous scaffold can be applied in articular cartilage tissue engineering and may have great potential to in other types of tissue engineering applications. PMID:25961959

  5. Correlation between Focal Nodular Low Signal Changes in Hoffa's Fat Pad Adjacent to Anterior Femoral Cartilage and Focal Cartilage Defect Underlying This Region and Its Possible Implication

    PubMed Central

    Ng, Wuey Min

    2016-01-01

    Purpose. This study investigates the association between focal nodular mass with low signal in Hoffa's fat pad adjacent to anterior femoral cartilage of the knee (FNMHF) and focal cartilage abnormality in this region. Method. The magnetic resonance fast imaging employing steady-state acquisition sequence (MR FIESTA) sagittal and axial images of the B1 and C1 region (described later) of 148 patients were independently evaluated by two reviewers and categorized into four categories: normal, FNMHF with underlying focal cartilage abnormality, FNMHF with normal cartilage, and cartilage abnormality with no FNMHF. Results. There was a significant association (p = 0.00) between FNMHF and immediate adjacent focal cartilage abnormality with high interobserver agreement. The absence of focal nodular lesions next to the anterior femoral cartilage has a very high negative predictive value for chondral injury (97.8%). Synovial biopsy of focal nodular lesion done during arthroscopy revealed some fibrocollagenous tissue and no inflammatory cells. Conclusion. We postulate that the FNMHF adjacent to the cartilage defects is a form of normal healing response to the cartilage damage. One patient with FHMHF and underlying cartilage abnormality was rescanned six months later. In this patient, the FNMHF disappeared and normal cartilage was observed in the adjacent region which may support this theory. PMID:27213085

  6. Costal Cartilage Grafts in Rhinoplasty.

    PubMed

    Fedok, Fred G

    2016-01-01

    Cartilage grafts are regularly used in rhinoplasty. Septal and auricular donor sites are commonly used. Many situations compel the surgeon to use other alternative donor sites, including revision rhinoplasty and trauma. Many patients have a small amount of native septal cartilage and are unable to provide adequate septal cartilage to be used for frequently performed rhinoplasty maneuvers. The rib cage provides an enormous reserve of costal cartilage that can be carved into a variety of necessary grafts. A description of the technique of harvesting costal cartilage, a review of complications and management, and illustrative cases examples are included. PMID:26616708

  7. Terminally differentiated astrocytes lack DNA damage response signaling and are radioresistant but retain DNA repair proficiency

    PubMed Central

    Schneider, L; Fumagalli, M; d'Adda di Fagagna, F

    2012-01-01

    The impact and consequences of damage generation into genomic DNA, especially in the form of DNA double-strand breaks, and of the DNA-damage response (DDR) pathways that are promptly activated, have been elucidated in great detail. Most of this research, however, has been performed on proliferating, often cancerous, cell lines. In a mammalian body, the majority of cells are terminally differentiated (TD), and derives from a small pool of self-renewing somatic stem cells. Here, we comparatively studied DDR signaling and radiosensitivity in neural stem cells (NSC) and their TD-descendants, astrocytes – the predominant cells in the mammalian brain. Astrocytes have important roles in brain physiology, development and plasticity. We discovered that NSC activate canonical DDR upon exposure to ionizing radiation. Strikingly, astrocytes proved radioresistant, lacked functional DDR signaling, with key DDR genes such as ATM being repressed at the transcriptional level. Nevertheless, astrocytes retain the expression of non-homologous end-joining (NHEJ) genes and indeed they are DNA repair proficient. Unlike in NSC, in astrocytes DNA-PK seems to be the PI3K-like protein kinase responsible for γH2AX signal generation upon DNA damage. We also demonstrate the lack of functional DDR signaling activation in vivo in astrocytes of irradiated adult mouse brains, although adjacent neurons activate the DDR. PMID:21979466

  8. Protein Expression of DNA Damage Repair Proteins Dictates Response to Topoisomerase and PARP Inhibitors in Triple-Negative Breast Cancer

    PubMed Central

    Boerner, Julie L.; Nechiporchik, Nicole; Mueller, Kelly L.; Polin, Lisa; Heilbrun, Lance; Boerner, Scott A.; Zoratti, Gina L.; Stark, Karri; LoRusso, Patricia M.; Burger, Angelika

    2015-01-01

    Patients with metastatic triple-negative breast cancer (TNBC) have a poor prognosis. New approaches for the treatment of TNBC are needed to improve patient survival. The concept of synthetic lethality, brought about by inactivating complementary DNA repair pathways, has been proposed as a promising therapeutic option for these tumors. The TNBC tumor type has been associated with BRCA mutations, and inhibitors of Poly (ADP-ribose) polymerase (PARP), a family of proteins that facilitates DNA repair, have been shown to effectively kill BRCA defective tumors by preventing cells from repairing DNA damage, leading to a loss of cell viability and clonogenic survival. Here we present preclinical efficacy results of combining the PARP inhibitor, ABT-888, with CPT-11, a topoisomerase I inhibitor. CPT-11 binds to topoisomerase I at the replication fork, creating a bulky adduct that is recognized as damaged DNA. When DNA damage was stimulated with CPT-11, protein expression of the nucleotide excision repair enzyme ERCC1 inversely correlated with cell viability, but not clonogenic survival. However, 4 out of the 6 TNBC cells were synergistically responsive by cell viability and 5 out of the 6 TNBC cells were synergistically responsive by clonogenic survival to the combination of ABT-888 and CPT-11. In vivo, the BRCA mutant cell line MX-1 treated with CPT-11 alone demonstrated significant decreased tumor growth; this decrease was enhanced further with the addition of ABT-888. Decrease in tumor growth correlated with an increase in double strand DNA breaks as measured by γ-H2AX phosphorylation. In summary, inhibiting two arms of the DNA repair pathway simultaneously in TNBC cell lines, independent of BRCA mutation status, resulted in un-repairable DNA damage and subsequent cell death. PMID:25774912

  9. Cell and matrix modulation in prenatal and postnatal equine growth cartilage, zones of Ranvier and articular cartilage.

    PubMed

    Löfgren, Maria; Ekman, Stina; Svala, Emilia; Lindahl, Anders; Ley, Cecilia; Skiöldebrand, Eva

    2014-11-01

    Formation of synovial joints includes phenotypic changes of the chondrocytes and the organisation of their extracellular matrix is regulated by different factors and signalling pathways. Increased knowledge of the normal processes involved in joint development may be used to identify similar regulatory mechanisms during pathological conditions in the joint. Samples of the distal radius were collected from prenatal and postnatal equine growth plates, zones of Ranvier and articular cartilage with the aim of identifying Notch signalling components and cells with stem cell-like characteristics and to follow changes in matrix protein localisation during joint development. The localisation of the Notch signalling components Notch1, Delta4, Hes1, Notch dysregulating protein epidermal growth factor-like domain 7 (EGFL7), the stem cell-indicating factor Stro-1 and the matrix molecules cartilage oligomeric matrix protein (COMP), fibromodulin, matrilin-1 and chondroadherin were studied using immunohistochemistry. Spatial changes in protein localisations during cartilage maturation were observed for Notch signalling components and matrix molecules, with increased pericellular localisation indicating new synthesis and involvement of these proteins in the formation of the joint. However, it was not possible to characterise the phenotype of the chondrocytes based on their surrounding matrix during normal chondrogenesis. The zone of Ranvier was identified in all horses and characterised as an area expressing Stro-1, EGFL7 and chondroadherin with an absence of COMP and Notch signalling. Stro-1 was also present in cells close to the perichondrium, in the articular cartilage and in the fetal resting zone, indicating stem cell-like characteristics of these cells. The presence of stem cells in the articular cartilage will be of importance for the repair of damaged cartilage. Perivascular chondrocytes and hypertrophic cells of the cartilage bone interface displayed positive staining for

  10. Cell and matrix modulation in prenatal and postnatal equine growth cartilage, zones of Ranvier and articular cartilage

    PubMed Central

    Löfgren, Maria; Ekman, Stina; Svala, Emilia; Lindahl, Anders; Ley, Cecilia; Skiöldebrand, Eva

    2014-01-01

    Formation of synovial joints includes phenotypic changes of the chondrocytes and the organisation of their extracellular matrix is regulated by different factors and signalling pathways. Increased knowledge of the normal processes involved in joint development may be used to identify similar regulatory mechanisms during pathological conditions in the joint. Samples of the distal radius were collected from prenatal and postnatal equine growth plates, zones of Ranvier and articular cartilage with the aim of identifying Notch signalling components and cells with stem cell-like characteristics and to follow changes in matrix protein localisation during joint development. The localisation of the Notch signalling components Notch1, Delta4, Hes1, Notch dysregulating protein epidermal growth factor-like domain 7 (EGFL7), the stem cell-indicating factor Stro-1 and the matrix molecules cartilage oligomeric matrix protein (COMP), fibromodulin, matrilin-1 and chondroadherin were studied using immunohistochemistry. Spatial changes in protein localisations during cartilage maturation were observed for Notch signalling components and matrix molecules, with increased pericellular localisation indicating new synthesis and involvement of these proteins in the formation of the joint. However, it was not possible to characterise the phenotype of the chondrocytes based on their surrounding matrix during normal chondrogenesis. The zone of Ranvier was identified in all horses and characterised as an area expressing Stro-1, EGFL7 and chondroadherin with an absence of COMP and Notch signalling. Stro-1 was also present in cells close to the perichondrium, in the articular cartilage and in the fetal resting zone, indicating stem cell-like characteristics of these cells. The presence of stem cells in the articular cartilage will be of importance for the repair of damaged cartilage. Perivascular chondrocytes and hypertrophic cells of the cartilage bone interface displayed positive staining for

  11. Dynamic biomechanics correlate with histopathology in human tibial cartilage: a preliminary study.

    PubMed

    Young, Allan A; Appleyard, Richard C; Smith, Margaret M; Melrose, James; Little, Christopher B

    2007-09-01

    Improved staging of cartilage degeneration is required, particularly during early stages when minimal surface damage is visible arthroscopically. Degradation of articular cartilage extracellular matrix, resulting from degenerative changes associated with osteoarthritis, can influence its functional properties. Cartilage mechanical properties therefore may provide a quantitative method for monitoring degenerative change in this tissue. We determined whether dynamic mechanical properties of cartilage (effective shear modulus and phase lag) measured with a handheld indenter correlated with histopathology scores, proteoglycan, and collagen content or expression of chondrocyte-specific (aggrecan, collagen II) or dedifferentiation (collagen I and III) genes in human osteoarthritic cartilage with International Cartilage Repair Society scores of 0 to 1. We observed an association between the histopathologic stage of cartilage disease and dynamic shear modulus and phase lag. In contrast, there generally was a poor relationship between cartilage biomechanical properties and biochemistry with the only noteworthy correlation being between shear modulus and collagen. Phase lag but not shear modulus correlated with gene expression. These data support the potential of dynamic indentation for assessing the stage of cartilage degeneration in tissue with minimal gross surface damage.

  12. Dielectric Characterization of Costal Cartilage Chondrocytes

    PubMed Central

    Stacey, Michael W.; Sabuncu, Ahmet Can; Beskok, Ali

    2013-01-01

    Background Chondrocytes respond to biomechanical and bioelectrochemical stimuli by secreting appropriate extracellular matrix proteins that enables the tissue to withstand the large forces it experiences. Although biomechanical aspects of cartilage are well described, little is known of the bioelectrochemical responses. The focus of this study is to identify bioelectrical characteristics of human costal cartilage cells using dielectric spectroscopy. Methods Dielectric spectroscopy allows non-invasive probing of biological cells. An in house computer program is developed to extract dielectric properties of human costal cartilage cells from raw cell suspension impedance data measured by a microfluidic device. The dielectric properties of chondrocytes are compared with other cell types in order to comparatively assess the electrical nature of chondrocytes. Results The results suggest that electrical cell membrane characteristics of chondrocyte cells are close to cardiomyoblast cells, cells known to possess an array of active ion channels. The blocking effect of the non-specific ion channel blocker gadolinium is tested on chondrocytes with a significant reduction in both membrane capacitance and conductance. Conclusions We have utilized a microfluidic chamber to mimic biomechanical events through changes in bioelectrochemistry and described the dielectric properties of chondrocytes to be closer to cells derived from electrically excitably tissues General significance and interest The studydescribes dielectric characterization of human costal chondrocyte cells using physical tools, where results and methodology can be used to identify potential anomalies in bioelectrochemical responses that may lead to cartilage disorders. PMID:24016606

  13. Ultrasound evaluation of site-specific effect of simulated microgravity on articular cartilage.

    PubMed

    Wang, Qing; Zheng, Yong-Ping; Wang, Xiao-Yun; Huang, Yan-Ping; Liu, Mu-Qing; Wang, Shu-Zhe; Zhang, Zong-Kang; Guo, Xia

    2010-07-01

    Space flight induces acute changes in normal physiology in response to the microgravity environment. Articular cartilage is subjected to high loads under a ground reaction force on Earth. The objectives of this study were to investigate the site dependence of morphological and ultrasonic parameters of articular cartilage and to examine the site-specific responses of articular cartilage to simulated microgravity using ultrasound biomicroscopy (UBM). Six rats underwent tail suspension (simulated microgravity) for four weeks and six other rats were kept under normal Earth gravity as controls. Cartilage thickness, ultrasound roughness index (URI), integrated reflection coefficient (IRC) and integrated backscatter coefficient (IBC) of cartilage tissues, as well as histological degeneration were measured at the femoral head (FH), medial femoral condyle (MFC), lateral femoral condyle (LFC), patello-femoral groove (PFG) and patella (PAT). The results showed site dependence not significant in all UBM parameters except cartilage thickness (p < 0.01) in the control specimens. Only minor changes in articular cartilage were induced by 4-week tail suspension, although there were significant decreases in cartilage thickness at the MFC and PAT (p < 0.05) and a significant increase in URI at the PAT (p < 0.01). This study suggested that the 4-week simulated microgravity had only mild effects on femoral articular cartilage in the rat model. This information is useful for human spaceflight and clinical medicine in improving understanding of the effect of microgravity on articular cartilage. However, the effects of longer duration microgravity experience on articular cartilage need further investigation. PMID:20620696

  14. Imaging Strategies for Assessing Cartilage Composition in Osteoarthritis

    PubMed Central

    Matzat, Stephen J.; Kogan, Feliks; Fong, Grant W.; Gold, Garry E.

    2015-01-01

    Efforts to reduce the ever-increasing rates of osteoarthritis (OA) in the developed world require the ability to non-invasively detect the degradation of joint tissues before advanced damage has occurred. This is particularly relevant for damage to articular cartilage because this soft tissue lacks the capacity to repair itself following major damage and is essential to proper joint function. While conventional magnetic resonance imaging (MRI) provides sufficient contrast to visualize articular cartilage morphology, more advanced imaging strategies are necessary for understanding the underlying biochemical composition of cartilage that begins to break down in the earliest stages of OA. This review discusses the biochemical basis and the advantages and disadvantages associated with each of these techniques. Recent implementations for these techniques are touched upon, and future considerations for improving the research and clinical power of these imaging technologies are also discussed. PMID:25218737

  15. Multifunctional chondroitin sulphate for cartilage tissue-biomaterial integration

    NASA Astrophysics Data System (ADS)

    Wang, Dong-An; Varghese, Shyni; Sharma, Blanka; Strehin, Iossif; Fermanian, Sara; Gorham, Justin; Fairbrother, D. Howard; Cascio, Brett; Elisseeff, Jennifer H.

    2007-05-01

    A biologically active, high-strength tissue adhesive is needed for numerous medical applications in tissue engineering and regenerative medicine. Integration of biomaterials or implants with surrounding native tissue is crucial for both immediate functionality and long-term performance of the tissue. Here, we use the biopolymer chondroitin sulphate (CS), one of the major components of cartilage extracellular matrix, to develop a novel bioadhesive that is readily applied and acts quickly. CS was chemically functionalized with methacrylate and aldehyde groups on the polysaccharide backbone to chemically bridge biomaterials and tissue proteins via a twofold covalent link. Three-dimensional hydrogels (with and without cells) bonded to articular cartilage defects. In in vitro and in vivo functional studies this approach led to mechanical stability of the hydrogel and tissue repair in cartilage defects.

  16. Inhibition of CRMP2 phosphorylation repairs CNS by regulating neurotrophic and inhibitory responses.

    PubMed

    Nagai, Jun; Owada, Kazuki; Kitamura, Yoshiteru; Goshima, Yoshio; Ohshima, Toshio

    2016-03-01

    , and suppressed scarring were also observed by inhibiting CRMP2 phosphorylation. Therefore, inhibition of CRMP2 phosphorylation demonstrates the unique potential to repair SCI by both enhancing sensitivity to BDNF and reducing inhibitory responses. PMID:26795088

  17. The activation of DNA damage detection and repair responses in cleavage-stage rat embryos by a damaged paternal genome.

    PubMed

    Grenier, Lisanne; Robaire, Bernard; Hales, Barbara F

    2012-06-01

    Male germ cell DNA damage, after exposure to radiation, exogenous chemicals, or chemotherapeutic agents, is a major cause of male infertility. DNA-damaged spermatozoa can fertilize oocytes; this is of concern because there is limited information on the capacity of early embryos to repair a damaged male genome or on the fate of these embryos if repair is inadequate. We hypothesized that the early activation of DNA damage response in the early embryo is a critical determinant of its fate. The objective of this study was to assess the DNA damage response and mitochondrial function as a measure of the energy supply for DNA repair and general health in cleavage-stage embryos sired by males chronically exposed to an anticancer alkylating agent, cyclophosphamide. Male rats were treated with saline or cyclophosphamide (6 mg/kg/day) for 4 weeks and mated to naturally cycling females. Pronuclear two- and eight-cell embryos were collected for immunofluorescence analysis of mitochondrial function and biomarkers of the DNA damage response: γH2AX foci, 53BP1 reactivity, and poly(ADP-ribose) polymer formation. Mitochondrial activities did not differ between embryos sired by control- and cyclophosphamide-exposed males. At the two-cell stage, there was no treatment-related increase in DNA double-strand breaks; by the eight-cell stage, a significant increase was noted, as indicated by increased medium and large γH2AX foci. This was accompanied by a dampened DNA repair response, detected as a decrease in the nuclear intensity of poly(ADP-ribose) polymers. The micronuclei formed in cyclophosphamide-sired embryos contained large γH2AX foci and enhanced poly(ADP-ribose) polymer and 53BP1 reactivity compared with their nuclear counterparts. Thus, paternal cyclophosphamide exposure activated a DNA damage response in cleavage-stage embryos. Furthermore, this damage response may be useful in assessing embryo quality and developmental competence. PMID:22454429

  18. Splicing controls the ubiquitin response during DNA double-strand break repair

    PubMed Central

    Pederiva, C; Böhm, S; Julner, A; Farnebo, M

    2016-01-01

    Although evidence that splicing regulates DNA repair is accumulating, the underlying mechanism(s) remain unclear. Here, we report that short-term inhibition of pre-mRNA splicing by spliceosomal inhibitors impairs cellular repair of DNA double-strand breaks. Indeed, interference with splicing as little as 1 h prior to irradiation reduced ubiquitylation of damaged chromatin and impaired recruitment of the repair factors WRAP53β, RNF168, 53BP1, BRCA1 and RAD51 to sites of DNA damage. Consequently, splicing-deficient cells exhibited significant numbers of residual γH2AX foci, as would be expected if DNA repair is defective. Furthermore, we show that this is due to downregulation of the E3 ubiquitin ligase RNF8 and that re-introduction of this protein into splicing-deficient cells restores ubiquitylation at sites of DNA damage, accumulation of downstream factors and subsequent repair. Moreover, downregulation of RNF8 explains the defective repair associated with knockdown of various splicing factors in recent genome-wide siRNA screens and, significantly, overexpression of RNF8 counteracts this defect. These discoveries reveal a mechanism that may not only explain how splicing regulates repair of double-strand breaks, but also may underlie various diseases caused by deregulation of splicing factors, including cancer. PMID:27315300

  19. Engineering Lubrication in Articular Cartilage

    PubMed Central

    McNary, Sean M.; Athanasiou, Kyriacos A.

    2012-01-01

    Despite continuous progress toward tissue engineering of functional articular cartilage, significant challenges still remain. Advances in morphogens, stem cells, and scaffolds have resulted in enhancement of the bulk mechanical properties of engineered constructs, but little attention has been paid to the surface mechanical properties. In the near future, engineered tissues will be able to withstand and support the physiological compressive and tensile forces in weight-bearing synovial joints such as the knee. However, there is an increasing realization that these tissue-engineered cartilage constructs will fail without the optimal frictional and wear properties present in native articular cartilage. These characteristics are critical to smooth, pain-free joint articulation and a long-lasting, durable cartilage surface. To achieve optimal tribological properties, engineered cartilage therapies will need to incorporate approaches and methods for functional lubrication. Steady progress in cartilage lubrication in native tissues has pushed the pendulum and warranted a shift in the articular cartilage tissue-engineering paradigm. Engineered tissues should be designed and developed to possess both tribological and mechanical properties mirroring natural cartilage. In this article, an overview of the biology and engineering of articular cartilage structure and cartilage lubrication will be presented. Salient progress in lubrication treatments such as tribosupplementation, pharmacological, and cell-based therapies will be covered. Finally, frictional assays such as the pin-on-disk tribometer will be addressed. Knowledge related to the elements of cartilage lubrication has progressed and, thus, an opportune moment is provided to leverage these advances at a critical step in the development of mechanically and tribologically robust, biomimetic tissue-engineered cartilage. This article is intended to serve as the first stepping stone toward future studies in functional

  20. Engineering lubrication in articular cartilage.

    PubMed

    McNary, Sean M; Athanasiou, Kyriacos A; Reddi, A Hari

    2012-04-01

    Despite continuous progress toward tissue engineering of functional articular cartilage, significant challenges still remain. Advances in morphogens, stem cells, and scaffolds have resulted in enhancement of the bulk mechanical properties of engineered constructs, but little attention has been paid to the surface mechanical properties. In the near future, engineered tissues will be able to withstand and support the physiological compressive and tensile forces in weight-bearing synovial joints such as the knee. However, there is an increasing realization that these tissue-engineered cartilage constructs will fail without the optimal frictional and wear properties present in native articular cartilage. These characteristics are critical to smooth, pain-free joint articulation and a long-lasting, durable cartilage surface. To achieve optimal tribological properties, engineered cartilage therapies will need to incorporate approaches and methods for functional lubrication. Steady progress in cartilage lubrication in native tissues has pushed the pendulum and warranted a shift in the articular cartilage tissue-engineering paradigm. Engineered tissues should be designed and developed to possess both tribological and mechanical properties mirroring natural cartilage. In this article, an overview of the biology and engineering of articular cartilage structure and cartilage lubrication will be presented. Salient progress in lubrication treatments such as tribosupplementation, pharmacological, and cell-based therapies will be covered. Finally, frictional assays such as the pin-on-disk tribometer will be addressed. Knowledge related to the elements of cartilage lubrication has progressed and, thus, an opportune moment is provided to leverage these advances at a critical step in the development of mechanically and tribologically robust, biomimetic tissue-engineered cartilage. This article is intended to serve as the first stepping stone toward future studies in functional

  1. Regeneration of Articular Cartilage Surface: Morphogens, Cells, and Extracellular Matrix Scaffolds.

    PubMed

    Sakata, Ryosuke; Iwakura, Takashi; Reddi, A Hari

    2015-10-01

    The articular cartilage is a well-organized tissue for smooth and friction-free joint movement for locomotion in animals and humans. Adult articular cartilage has a very low self-regeneration capacity due to its avascular nature. The regeneration of articular cartilage surface is critical to prevent the progression to osteoarthritis (OA). Although various joint resurfacing procedures in experimental articular cartilage defects have been developed, no standardized clinical protocol has yet been established. The three critical ingredients for tissue regeneration are morphogens and growth factors, cells, and scaffolds. The concepts based on the regeneration triad have been extensively investigated in animal models. However, these studies in animal models have demonstrated variable results and outcomes. An optimal animal model must precisely mimic and model the sequence of events in articular cartilage regeneration in human. In this article, the progress and remaining challenges in articular cartilage regeneration in animal models are reviewed. The role of individual morphogens and growth factors in cartilage regeneration has been investigated. In normal articular cartilage homeostasis, morphogens and growth factors function sequentially in tissue regeneration. Mesenchymal stem cell-based repair of articular cartilage defects, performed with or without various growth factors and scaffolds, has been widely attempted in animal models. Stem cells, including embryonic and adult stem cells and induced pluripotent stem cells, have also been reported as attractive cell sources for articular cartilage surface regeneration. Several studies with regard to scaffolds have been advanced, including recent investigations based on nanomaterials, functional mechanocompatible scaffolds, multilayered scaffolds, and extracellular matrix scaffolds for articular cartilage surface regeneration. Continuous refinement of animal models in chondral and osteochondral defects provide opportunities

  2. Mesenchymal stem cell-based cartilage tissue engineering: cells, scaffold and biology.

    PubMed

    Song, L; Baksh, D; Tuan, R S

    2004-01-01

    Cartilage repair and regeneration by stem cell-based tissue engineering could be of enormous therapeutic and economic potential benefit for an aging population. However, to use stem cells effectively, their natural environment must be understood in order to expand them in vitro without compromising their multilineage potential and their specific differentiation program. Collaboration between diverse academic disciplines and between research and regulatory government agencies and industry is crucial before cell-based cartilage tissue engineering can achieve its full therapeutic potential.

  3. Lubrication of Articular Cartilage.

    PubMed

    Jahn, Sabrina; Seror, Jasmine; Klein, Jacob

    2016-07-11

    The major synovial joints such as hips and knees are uniquely efficient tribological systems, able to articulate over a wide range of shear rates with a friction coefficient between the sliding cartilage surfaces as low as 0.001 up to pressures of more than 100 atm. No human-made material can match this. The means by which such surfaces maintain their very low friction has been intensively studied for decades and has been attributed to fluid-film and boundary lubrication. Here, we focus especially on the latter: the reduction of friction by molecular layers at the sliding cartilage surfaces. In particular, we discuss such lubrication in the light of very recent advances in our understanding of boundary effects in aqueous media based on the paradigms of hydration lubrication and of the synergism between different molecular components of the synovial joints (namely hyaluronan, lubricin, and phospholipids) in enabling this lubrication.

  4. Cartilage-forming tumors.

    PubMed

    Qasem, Shadi A; DeYoung, Barry R

    2014-01-01

    Cartilage-forming tumors as a group are the most common primary bone tumors; this is largely due to the common occurrence of asymptomatic benign lesions such as osteochondroma and enchondroma. The common feature of these tumors is the presence of chondrocytic cells and the formation of cartilaginous tumor matrix. Some of these tumors are true neoplasms while others are hamartomas or developmental abnormalities. The morphologic heterogeneity of these tumors may be explained by a common multipotent mesenchymal cell differentiating along the lines of fetal-adult cartilage maturation. Recently mutations in IDH1 and IDH2 have been detected in a variety of benign and malignant cartilaginous tumors.(1-4.) PMID:24680178

  5. A composite scaffold of MSC affinity peptide-modified demineralized bone matrix particles and chitosan hydrogel for cartilage regeneration

    NASA Astrophysics Data System (ADS)

    Meng, Qingyang; Man, Zhentao; Dai, Linghui; Huang, Hongjie; Zhang, Xin; Hu, Xiaoqing; Shao, Zhenxing; Zhu, Jingxian; Zhang, Jiying; Fu, Xin; Duan, Xiaoning; Ao, Yingfang

    2015-12-01

    Articular cartilage injury is still a significant challenge because of the poor intrinsic healing potential of cartilage. Stem cell-based tissue engineering is a promising technique for cartilage repair. As cartilage defects are usually irregular in clinical settings, scaffolds with moldability that can fill any shape of cartilage defects and closely integrate with the host cartilage are desirable. In this study, we constructed a composite scaffold combining mesenchymal stem cells (MSCs) E7 affinity peptide-modified demineralized bone matrix (DBM) particles and chitosan (CS) hydrogel for cartilage engineering. This solid-supported composite scaffold exhibited appropriate porosity, which provided a 3D microenvironment that supports cell adhesion and proliferation. Cell proliferation and DNA content analysis indicated that the DBM-E7/CS scaffold promoted better rat bone marrow-derived MSCs (BMMSCs) survival than the CS or DBM/CS groups. Meanwhile, the DBM-E7/CS scaffold increased matrix production and improved chondrogenic differentiation ability of BMMSCs in vitro. Furthermore, after implantation in vivo for four weeks, compared to those in control groups, the regenerated issue in the DBM-E7/CS group exhibited translucent and superior cartilage-like structures, as indicated by gross observation, histological examination, and assessment of matrix staining. Overall, the functional composite scaffold of DBM-E7/CS is a promising option for repairing irregularly shaped cartilage defects.

  6. A composite scaffold of MSC affinity peptide-modified demineralized bone matrix particles and chitosan hydrogel for cartilage regeneration.

    PubMed

    Meng, Qingyang; Man, Zhentao; Dai, Linghui; Huang, Hongjie; Zhang, Xin; Hu, Xiaoqing; Shao, Zhenxing; Zhu, Jingxian; Zhang, Jiying; Fu, Xin; Duan, Xiaoning; Ao, Yingfang

    2015-12-03

    Articular cartilage injury is still a significant challenge because of the poor intrinsic healing potential of cartilage. Stem cell-based tissue engineering is a promising technique for cartilage repair. As cartilage defects are usually irregular in clinical settings, scaffolds with moldability that can fill any shape of cartilage defects and closely integrate with the host cartilage are desirable. In this study, we constructed a composite scaffold combining mesenchymal stem cells (MSCs) E7 affinity peptide-modified demineralized bone matrix (DBM) particles and chitosan (CS) hydrogel for cartilage engineering. This solid-supported composite scaffold exhibited appropriate porosity, which provided a 3D microenvironment that supports cell adhesion and proliferation. Cell proliferation and DNA content analysis indicated that the DBM-E7/CS scaffold promoted better rat bone marrow-derived MSCs (BMMSCs) survival than the CS or DBM/CS groups. Meanwhile, the DBM-E7/CS scaffold increased matrix production and improved chondrogenic differentiation ability of BMMSCs in vitro. Furthermore, after implantation in vivo for four weeks, compared to those in control groups, the regenerated issue in the DBM-E7/CS group exhibited translucent and superior cartilage-like structures, as indicated by gross observation, histological examination, and assessment of matrix staining. Overall, the functional composite scaffold of DBM-E7/CS is a promising option for repairing irregularly shaped cartilage defects.

  7. A composite scaffold of MSC affinity peptide-modified demineralized bone matrix particles and chitosan hydrogel for cartilage regeneration

    PubMed Central

    Meng, Qingyang; Man, Zhentao; Dai, Linghui; Huang, Hongjie; Zhang, Xin; Hu, Xiaoqing; Shao, Zhenxing; Zhu, Jingxian; Zhang, Jiying; Fu, Xin; Duan, Xiaoning; Ao, Yingfang

    2015-01-01

    Articular cartilage injury is still a significant challenge because of the poor intrinsic healing potential of cartilage. Stem cell-based tissue engineering is a promising technique for cartilage repair. As cartilage defects are usually irregular in clinical settings, scaffolds with moldability that can fill any shape of cartilage defects and closely integrate with the host cartilage are desirable. In this study, we constructed a composite scaffold combining mesenchymal stem cells (MSCs) E7 affinity peptide-modified demineralized bone matrix (DBM) particles and chitosan (CS) hydrogel for cartilage engineering. This solid-supported composite scaffold exhibited appropriate porosity, which provided a 3D microenvironment that supports cell adhesion and proliferation. Cell proliferation and DNA content analysis indicated that the DBM-E7/CS scaffold promoted better rat bone marrow-derived MSCs (BMMSCs) survival than the CS or DBM/CS groups. Meanwhile, the DBM-E7/CS scaffold increased matrix production and improved chondrogenic differentiation ability of BMMSCs in vitro. Furthermore, after implantation in vivo for four weeks, compared to those in control groups, the regenerated issue in the DBM-E7/CS group exhibited translucent and superior cartilage-like structures, as indicated by gross observation, histological examination, and assessment of matrix staining. Overall, the functional composite scaffold of DBM-E7/CS is a promising option for repairing irregularly shaped cartilage defects. PMID:26632447

  8. Cartilage analysis by reflection spectroscopy

    NASA Astrophysics Data System (ADS)

    Laun, T.; Muenzer, M.; Wenzel, U.; Princz, S.; Hessling, M.

    2015-07-01

    A cartilage bioreactor with analytical functions for cartilage quality monitoring is being developed. For determining cartilage composition, reflection spectroscopy in the visible (VIS) and near infrared (NIR) spectral region is evaluated. Main goal is the determination of the most abundant cartilage compounds water, collagen I and collagen II. Therefore VIS and NIR reflection spectra of different cartilage samples of cow, pig and lamb are recorded. Due to missing analytical instrumentation for identifying the cartilage composition of these samples, typical literature concentration values are used for the development of chemometric models. In spite of these limitations the chemometric models provide good cross correlation results for the prediction of collagen I and II and water concentration based on the visible and the NIR reflection spectra.

  9. STUDIES ON CARTILAGE

    PubMed Central

    Sheldon, Huntington; Robinson, Robert A.

    1960-01-01

    Electron microscope observations on rabbit ear cartilage following the administration of papain show that both the elastic component of the matrix and the amorphous material disappear leaving a matrix which consists of delicate fibrils which are presumed to be collagen. This unmasking of fibrils coincides with the appearance of an abnormal component in the electrophoretic pattern of the rabbit's serum. The chondrocytes show vacuoles in their cytoplasm which appear at the same time that the cells appear crenated in the light microscope. A ruffly appearance of the cell surface membrane coincides with this vacuolization, and vacuoles often appear open and in continuity with the extracellular space. The resurgence of the rabbit ear is accompanied by a reconstitution of both the amorphous material and the elastic component of the matrix. During this period numerous dilated cisternae of the endoplasmic reticulum which contain a moderately dense material are present in the chondrocyte cytoplasm. We have been unable to demonstrate a direct relationship between the elastic component of the matrix and a particular component of the chondrocyte cytoplasm, but it is clear that changes occur in the cartilage cell cytoplasm during both the depletion and reconstitution of the matrix. Previous studies on the effect of papain on elastic tissue are noted and the possible relationships between changes in the cells and matrix of this elastic cartilage are discussed. PMID:19866569

  10. Age related changes and osteochondrosis in swine articular and epiphyseal cartilage: light ane electron microscopy.

    PubMed

    Bhatnagar, R; Christian, R G; Nakano, T; Aherne, F X; Thompson, J R

    1981-04-01

    Age related changes and osteochondrosis in swine were studied using light microscopy and electron microscopy in articular cartilage and light microscopy and epiphyseal cartilage of swine from three days to 30 weeks of age. Thickness, cellularity and vascularity of both the epiphyseal and articular cartilage, decreased as the swine aged. Osteochondrotic changes included formation of "plugs" of cartilage indicating localized failure of ossification and separation and space formation in epiphyseal cartilage. Eosinophilic streaks and space formation in epiphyseal cartilage was observed in relation to epiphyseal separation. Electron microscopy showed a continuous fibrillar layer on the surface of the cartilage corresponding to the lamina splendens of light microscopy. This layer increased in the thickness and showed accumulation of amorphous material between the fibrils with aging. In the matrix, the orientation and distribution of the collagen fibers changed with growth and thicker fibers with clear sub banding were more common in older age groups. Also, necrotic cells, glycogen containing bodies and cellular debris were noticed in the matrix of normal cartilage in old animals. Chondrocytes in the younger cartilage showed accumulation of organelles responsible for protein synthesis; while Golgi bodies, vesicles, lysosomes, well developed foot processes and other inclusions were noticed in older cartilage. Cartilage erosions had a clumped and disrupted lamina splendens on the surface and electron lucent patches in the ground substances of the matrix and chondrocyte cytoplasm. PMID:7260732

  11. Spontaneous Minced Cartilage Procedure for Unexpectedly Large Femoral Condyle Surface Defect.

    PubMed

    Salzmann, G M; Baumann, G A; Preiss, S

    2016-01-01

    Articular cartilage defects at the knee joint are being identified and treated with increasing frequency. Chondrocytes may have strongest potential to generate high-quality repair tissue within the defective region, in particular when large diameter defects are present. Autologous chondrocyte implantation is not available in every country. We present a case where we spontaneously covered an acute cartilage defect, which was significantly larger than expected and loose during initial arthroscopic inspection after reading preoperative MRI, by mincing the separated fragment and directly implanting the autologous cartilage chips into the defective region. PMID:27504207

  12. Spontaneous Minced Cartilage Procedure for Unexpectedly Large Femoral Condyle Surface Defect

    PubMed Central

    Preiss, S.

    2016-01-01

    Articular cartilage defects at the knee joint are being identified and treated with increasing frequency. Chondrocytes may have strongest potential to generate high-quality repair tissue within the defective region, in particular when large diameter defects are present. Autologous chondrocyte implantation is not available in every country. We present a case where we spontaneously covered an acute cartilage defect, which was significantly larger than expected and loose during initial arthroscopic inspection after reading preoperative MRI, by mincing the separated fragment and directly implanting the autologous cartilage chips into the defective region. PMID:27504207

  13. Head and neck cancer cell lines exhibit differential mitochondrial repair deficiency in response to 4NQO.

    PubMed

    Kim, Michael M; Glazer, Chad A; Mambo, Elizabeth; Chatterjee, Aditi; Zhao, Ming; Sidransky, David; Califano, Joseph A

    2006-02-01

    Constituents of tobacco can cause DNA adduct formation and are implicated in head and neck squamous cell cancer (HNSC) development. We investigated the capacity of HNSC cell lines to repair mitochondrial DNA (mtDNA) damage induced by a DNA adduct-forming agent. HNSC cell lines underwent 4-nitroquinoline 1-oxide (4NQO) exposure with subsequent rescue with normal media. Real-time quantitative PCR for nuclear DNA (nDNA) and mtDNA was performed. mtDNA to nDNA ratios were calculated and standardized to mock-treated cells to assess mtDNA repair ability. Two of three tested cancer cell lines exposed to 4NQO exhibited consistent decreases in mtDNA/nDNA ratios throughout the different repair timepoints. At 24 h mtDNA/nDNA ratios of JHU-O19 and JHU-O22 decreased to 63% and 60% of controls, respectively. Conversely, a control keratinocyte cell line exhibited overall increases in mtDNA/nDNA ratios compared to baseline suggesting intact DNA repair mechanisms. By using a DNA adduct formation and repair model featuring 4NQO and HNSC cell lines, we have implicated faulty mtDNA repair as having a potential role in HNSC.

  14. A high throughput mechanical screening device for cartilage tissue engineering.

    PubMed

    Mohanraj, Bhavana; Hou, Chieh; Meloni, Gregory R; Cosgrove, Brian D; Dodge, George R; Mauck, Robert L

    2014-06-27

    Articular cartilage enables efficient and near-frictionless load transmission, but suffers from poor inherent healing capacity. As such, cartilage tissue engineering strategies have focused on mimicking both compositional and mechanical properties of native tissue in order to provide effective repair materials for the treatment of damaged or degenerated joint surfaces. However, given the large number design parameters available (e.g. cell sources, scaffold designs, and growth factors), it is difficult to conduct combinatorial experiments of engineered cartilage. This is particularly exacerbated when mechanical properties are a primary outcome, given the long time required for testing of individual samples. High throughput screening is utilized widely in the pharmaceutical industry to rapidly and cost-effectively assess the effects of thousands of compounds for therapeutic discovery. Here we adapted this approach to develop a high throughput mechanical screening (HTMS) system capable of measuring the mechanical properties of up to 48 materials simultaneously. The HTMS device was validated by testing various biomaterials and engineered cartilage constructs and by comparing the HTMS results to those derived from conventional single sample compression tests. Further evaluation showed that the HTMS system was capable of distinguishing and identifying 'hits', or factors that influence the degree of tissue maturation. Future iterations of this device will focus on reducing data variability, increasing force sensitivity and range, as well as scaling-up to even larger (96-well) formats. This HTMS device provides a novel tool for cartilage tissue engineering, freeing experimental design from the limitations of mechanical testing throughput.

  15. Should we use cells, biomaterials, or tissue engineering for cartilage regeneration?

    PubMed

    Bernhard, Jonathan C; Vunjak-Novakovic, Gordana

    2016-01-01

    For a long time, cartilage has been a major focus of the whole field of tissue engineering, both because of the constantly growing need for more effective options for joint repair and the expectation that this apparently simple tissue will be easy to engineer. After several decades, cartilage regeneration has proven to be anything but easy. With gratifying progress in our understanding of the factors governing cartilage development and function, and cell therapy being successfully used for several decades, there is still a lot to do. We lack reliable methods to generate durable articular cartilage that would resemble the original tissue lost to injury or disease. The question posed here is whether the answer would come from the methods using cells, biomaterials, or tissue engineering. We present a concise review of some of the most meritorious efforts in each area, and propose that the solution will most likely emerge from the ongoing attempts to recapitulate certain aspects of native cartilage development. While an ideal recipe for cartilage regeneration is yet to be formulated, we believe that it will contain cell, biomaterial, and tissue engineering approaches, blended into an effective method for seamless repair of articular cartilage. PMID:27089917

  16. Isolation, Culture, and Characterization of Chicken Cartilage Stem/Progenitor Cells

    PubMed Central

    Li, Lu; Ma, Yuehui; Li, Xianglong; Li, Xiangchen; Bai, Chunyu; Ji, Meng; Zhang, Shuang; Guan, Weijun; Li, Junjie

    2015-01-01

    A chondrocyte progenitor population isolated from the surface zone of articular cartilage has become a promising cell source for cell-based cartilage repair. The cartilage-derived stem/progenitor cells are multipotent stem cells, which can differentiate into three cell types in vitro including adipocytes, osteoblasts, and chondrocytes. Much work has been done on cartilage stem/progenitor cells (CSPCs) from people, horses, and cattle, but the relatively little literature has been published about these cells in chickens. In our work, CSPCs were isolated from chicken embryos in incubated eggs for 20 days. In order to inquire into the biological characteristics of chicken CSPCs, immunofluorescence, reverse transcription-polymerase chain reaction (RT-PCR), and flow cytometry were adopted to detect the characteristic surface markers of CSPCs. Primary CSPCs were subcultured to passage 22 and, for purpose of knowing the change of cell numbers, we drew the growth curves. Isolated CSPCs were induced to adipocytes, osteoblasts, and chondrocytes. Our results suggest that we have identified and characterised a novel cartilage progenitor population resident in chicken articular cartilage and CSPCs isolated from chickens possess similar biological characteristics to those from other species, which will greatly benefit future cell-based cartilage repair therapies. PMID:26351636

  17. FGF, TGFβ and Wnt crosstalk: embryonic to in vitro cartilage development from mesenchymal stem cells.

    PubMed

    Cleary, Mairéad A; van Osch, Gerjo J V M; Brama, Pieter A; Hellingman, Catharine A; Narcisi, Roberto

    2015-04-01

    Articular cartilage is easily damaged, yet difficult to repair. Cartilage tissue engineering seems a promising therapeutic solution to restore articular cartilage structure and function, with mesenchymal stem cells (MSCs) receiving increasing attention for their promise to promote cartilage repair. It is known from embryology that members of the fibroblast growth factor (FGF), transforming growth factor-β (TGFβ) and wingless-type (Wnt) protein families are involved in controlling different differentiation stages during chondrogenesis. Individually, these pathways have been extensively studied but so far attempts to recapitulate embryonic development in in vitro MSC chondrogenesis have failed to produce stable and functioning articular cartilage; instead, transient hypertrophic cartilage is obtained. We believe a better understanding of the simultaneous integration of these factors will improve how we relate embryonic chondrogenesis to in vitro MSC chondrogenesis. This narrative review attempts to define current knowledge on the crosstalk between the FGF, TGFβ and Wnt signalling pathways during different stages of mesenchymal chondrogenesis. Connecting embryogenesis and in vitro differentiation of human MSCs might provide insights into how to improve and progress cartilage tissue engineering for the future.

  18. Further phenotypic characterization of pso mutants of Saccharomyces cerevisiae with respect to DNA repair and response to oxidative stress.

    PubMed

    Pungartnik, Cristina; Picada, Jaqueline; Brendel, Martin; Henriques, João A P

    2002-03-31

    The sensitivity responses of seven pso mutants of Saccharomyces cerevisiae towards the mutagens N-nitrosodiethylamine (NDEA), 1,2:7,8-diepoxyoctane (DEO), and 8-hydroxyquinoline (8HQ) further substantiated their allocation into two distinct groups: genes PSO1 (allelic to REV3), PSO2 (SNM1), PSO4 (PRP19), and PSO5 (RAD16) constitute one group in that they are involved in repair of damaged DNA or in RNA processing whereas genes PSO6 (ERG3) and PSO7 (COX11) are related to metabolic steps protecting from oxidative stress and thus form a second group, not responsible for DNA repair. PSO3 has not yet been molecularly characterized but its pleiotropic phenotype would allow its integration into either group. The first three PSO genes of the DNA repair group and PSO3, apart from being sensitive to photo-activated psoralens, have another common phenotype: they are also involved in error-prone DNA repair. While all mutants of the DNA repair group and pso3 were sensitive to DEO and NDEA the pso6 mutant revealed WT or near WT resistance to these mutagens. As expected, the repair-proficient pso7-1 and cox11-Delta mutant alleles conferred high sensitivity to NDEA, a chemical known to be metabolized via redox cycling that yields hydroxylamine radicals and reactive oxygen species. All pso mutants exhibited some sensitivity to 8HQ and again pso7-1 and cox11-Delta conferred the highest sensitivity to this drug. Double mutant snm1-Delta cox11-Delta exhibited additivity of 8HQ and NDEA sensitivities of the single mutants, indicating that two different repair/recovery systems are involved in survival. DEO sensitivity of the double mutant was equal or less than that of the single snm1-Delta mutant. In order to determine if there was oxidative damage to nucleotide bases by these drugs we employed an established bacterial test with and without metabolic activation. After S9-mix biotransformation, NDEA and to a lesser extent 8HQ, lead to significantly higher mutagenesis in an Escherichia

  19. Comparative acoustic performance and mechanical properties of silk membranes for the repair of chronic tympanic membrane perforations.

    PubMed

    Allardyce, Benjamin J; Rajkhowa, Rangam; Dilley, Rodney J; Xie, Zhigang; Campbell, Luke; Keating, Adrian; Atlas, Marcus D; von Unge, Magnus; Wang, Xungai

    2016-12-01

    The acoustic and mechanical properties of silk membranes of different thicknesses were tested to determine their suitability as a repair material for tympanic membrane perforations. Membranes of different thickness (10-100μm) were tested to determine their frequency response and their resistance to pressure loads in a simulated ear canal model. Their mechanical rigidity to pressure loads was confirmed by tensile testing. These membranes were tested alongside animal cartilage, currently the strongest available myringoplasty graft as well as paper, which is commonly used for simpler procedures. Silk membranes showed resonant frequencies within the human hearing range and a higher vibrational amplitude than cartilage, suggesting that silk may offer good acoustic energy transfer characteristics. Silk membranes were also highly resistant to simulated pressure changes in the middle ear, suggesting they can resist retraction, a common cause of graft failure resulting from chronic negative pressures in the middle ear. Part of this strength can be explained by the substantially higher modulus of silk films compared with cartilage. This allows for the production of films that are much thinner than cartilage, with superior acoustic properties, but that still provide the same level of mechanical support as thicker cartilage. Together, these in vitro results suggest that silk membranes may provide good hearing outcomes while offering similar levels of mechanical support to the reconstructed middle ear. PMID:27479895

  20. MRI based knee cartilage assessment

    NASA Astrophysics Data System (ADS)

    Kroon, Dirk-Jan; Kowalski, Przemyslaw; Tekieli, Wojciech; Reeuwijk, Els; Saris, Daniel; Slump, Cornelis H.

    2012-03-01

    Osteoarthritis is one of the leading causes of pain and disability worldwide and a major health problem in developed countries due to the gradually aging population. Though the symptoms are easily recognized and described by a patient, it is difficult to assess the level of damage or loss of articular cartilage quantitatively. We present a novel method for fully automated knee cartilage thickness measurement and subsequent assessment of the knee joint. First, the point correspondence between a pre-segmented training bone model is obtained with use of Shape Context based non-rigid surface registration. Then, a single Active Shape Model (ASM) is used to segment both Femur and Tibia bone. The surfaces obtained are processed to extract the Bone-Cartilage Interface (BCI) points, where the proper segmentation of cartilage begins. For this purpose, the cartilage ASM is trained with cartilage edge positions expressed in 1D coordinates at the normals in the BCI points. The whole cartilage model is then constructed from the segmentations obtained in the previous step. An absolute thickness of the segmented cartilage is measured and compared to the mean of all training datasets, giving as a result the relative thickness value. The resulting cartilage structure is visualized and related to the segmented bone. In this way the condition of the cartilage is assessed over the surface. The quality of bone and cartilage segmentation is validated and the Dice's coefficients 0.92 and 0.86 for Femur and Tibia bones and 0.45 and 0.34 for respective cartilages are obtained. The clinical diagnostic relevance of the obtained thickness mapping is being evaluated retrospectively. We hope to validate it prospectively for prediction of clinical outcome the methods require improvements in accuracy and robustness.

  1. Towards Regeneration of Articular Cartilage

    PubMed Central

    Iwamoto, Masahiro; Ohta, Yoichi; Larmour, Colleen; Enomoto-Iwamoto, Motomi

    2014-01-01

    Articular cartilage is classified into permanent hyaline cartilage and has significant differences in structure, extracelluar matrix components, gene expression profile, and mechanical property from transient hyaline cartilage found in growth plate. In the process of synovial joint development, articular cartilage is originated from the interzone, developing at the edge of the cartilaginous anlagen, it establishes zonal structure over time and supports smooth movement of the synovial joint through life. The cascade actions of key regulators such as Wnts, GDF5, Erg, and PTHLH coordinate sequential steps of articular cartilage formation. Articular chondrocytes are restrictedly controlled not to differentiate into a hypertrophic stage by autocrine and paracrine factors and extracerllular matrix microenvironment, but retain potential to undergo hypertrophy. The basal calcified zone of articular cartilage is connected with subchondral bone, but not invaded by blood vessels nor replaced by bone, which is highly contrasted with the growth plate. Articular cartilage has limited regenerative capacity, but likely possesses and potentially uses intrinsic stem cell source in the superficial layer, Ranvier’s groove, the intra-articular tissues such as synovium and fat pad, and marrow below the subchondral bone. Considering the biological views on articular cartilage, several important points are raised for regeneration of articular cartilage. We should evaluate the nature of regenerated cartilage as permanent hyaline cartilage and not just hyaline cartilage. We should study how a hypertrophic phenotype of transplanted cells can be lastingly suppressed in regenerating tissue. Further, we should develop the methods and reagents to activate recruitment of intrinsic stem/progenitor cells into the damaged site. PMID:24078496

  2. Ultrasound arthroscopy of human knee cartilage and subchondral bone in vivo.

    PubMed

    Liukkonen, Jukka; Lehenkari, Petri; Hirvasniemi, Jukka; Joukainen, Antti; Virén, Tuomas; Saarakkala, Simo; Nieminen, Miika T; Jurvelin, Jukka S; Töyräs, Juha

    2014-09-01

    Arthroscopic ultrasound imaging enables quantitative evaluation of articular cartilage. However, the potential of this technique for evaluation of subchondral bone has not been investigated in vivo. In this study, we address this issue in clinical arthroscopy of the human knee (n = 11) by determining quantitative ultrasound (9 MHz) reflection and backscattering parameters for cartilage and subchondral bone. Furthermore, in each knee, seven anatomical sites were graded using the International Cartilage Repair Society (ICRS) system based on (i) conventional arthroscopy and (ii) ultrasound images acquired in arthroscopy with a miniature transducer. Ultrasound enabled visualization of articular cartilage and subchondral bone. ICRS grades based on ultrasound images were higher (p < 0.05) than those based on conventional arthroscopy. The higher ultrasound-based ICRS grades were expected as ultrasound reveals additional information on, for example, the relative depth of the lesion. In line with previous literature, ultrasound reflection and scattering in cartilage varied significantly (p < 0.05) along the ICRS scale. However, no significant correlation between ultrasound parameters and structure or density of subchondral bone could be demonstrated. To conclude, arthroscopic ultrasound imaging had a significant effect on clinical grading of cartilage, and it was found to provide quantitative information on cartilage. The lack of correlation between the ultrasound parameters and bone properties may be related to lesser bone change or excessive attenuation in overlying cartilage and insufficient power of the applied miniature transducer. PMID:25023111

  3. Ultrasound arthroscopy of human knee cartilage and subchondral bone in vivo.

    PubMed

    Liukkonen, Jukka; Lehenkari, Petri; Hirvasniemi, Jukka; Joukainen, Antti; Virén, Tuomas; Saarakkala, Simo; Nieminen, Miika T; Jurvelin, Jukka S; Töyräs, Juha

    2014-09-01

    Arthroscopic ultrasound imaging enables quantitative evaluation of articular cartilage. However, the potential of this technique for evaluation of subchondral bone has not been investigated in vivo. In this study, we address this issue in clinical arthroscopy of the human knee (n = 11) by determining quantitative ultrasound (9 MHz) reflection and backscattering parameters for cartilage and subchondral bone. Furthermore, in each knee, seven anatomical sites were graded using the International Cartilage Repair Society (ICRS) system based on (i) conventional arthroscopy and (ii) ultrasound images acquired in arthroscopy with a miniature transducer. Ultrasound enabled visualization of articular cartilage and subchondral bone. ICRS grades based on ultrasound images were higher (p < 0.05) than those based on conventional arthroscopy. The higher ultrasound-based ICRS grades were expected as ultrasound reveals additional information on, for example, the relative depth of the lesion. In line with previous literature, ultrasound reflection and scattering in cartilage varied significantly (p < 0.05) along the ICRS scale. However, no significant correlation between ultrasound parameters and structure or density of subchondral bone could be demonstrated. To conclude, arthroscopic ultrasound imaging had a significant effect on clinical grading of cartilage, and it was found to provide quantitative information on cartilage. The lack of correlation between the ultrasound parameters and bone properties may be related to lesser bone change or excessive attenuation in overlying cartilage and insufficient power of the applied miniature transducer.

  4. Considerations on the use of ear chondrocytes as donor chondrocytes for cartilage tissue engineering.

    PubMed

    Van Osch, Gerjo J V M; Mandl, Erik W; Jahr, Holger; Koevoet, Wendy; Nolst-Trenité, Gilbert; Verhaar, Jan A N

    2004-01-01

    Articular cartilage is often used for research on cartilage tissue engineering. However, ear cartilage is easier to harvest, with less donor-site morbidity. The aim of this study was to evaluate whether adult human ear chondrocytes were capable of producing cartilage after expansion in monolayer culture. Cell yield per gram of cartilage was twice as high for ear than for articular cartilage. Moreover, ear chondrocytes proliferated faster. Cell proliferation could be further stimulated by the use of serum-free medium with Fibroblast Growth Factor 2 (FGF2) in stead of medium with 10% serum. To evaluate chondrogenic capacity, multiplied chondrocytes were suspended in alginate and implanted subcutaneously in athymic mice. After 8 weeks the constructs demonstrated a proteoglycan-rich matrix that contained collagen type II. Constructs of ear chondrocytes showed a faint staining for elastin. Quantitative RT-PCR revealed that expression of collagen type II was 2-fold upregulated whereas expression of collagen type I was 2-fold down regulated in ear chondrocytes expanded in serum-free medium with FGF2 compared to serum-containing medium. Expression of alkaline phosphatase and collagen type X were low indicating the absence of terminal differentiation. We conclude that ear chondrocytes can be used as donor chondrocytes for cartilage tissue engineering. Furthermore, it may proof to be a promising alternative cell source to engineer cartilage for articular repair.

  5. The chondrocyte clock gene Bmal1 controls cartilage homeostasis and integrity

    PubMed Central

    Dudek, Michal; Gossan, Nicole; Yang, Nan; Im, Hee-Jeong; Ruckshanthi, Jayalath P.D.; Yoshitane, Hikari; Li, Xin; Jin, Ding; Wang, Ping; Boudiffa, Maya; Bellantuono, Ilaria; Fukada, Yoshitaka; Boot-Handford, Ray P.; Meng, Qing-Jun

    2015-01-01

    Osteoarthritis (OA) is the most prevalent and debilitating joint disease, and there are currently no effective disease-modifying treatments available. Multiple risk factors for OA, such as aging, result in progressive damage and loss of articular cartilage. Autonomous circadian clocks have been identified in mouse cartilage, and environmental disruption of circadian rhythms in mice predisposes animals to OA-like damage. However, the contribution of the cartilage clock mechanisms to the maintenance of tissue homeostasis is still unclear. Here, we have shown that expression of the core clock transcription factor BMAL1 is disrupted in human OA cartilage and in aged mouse cartilage. Furthermore, targeted Bmal1 ablation in mouse chondrocytes abolished their circadian rhythm and caused progressive degeneration of articular cartilage. We determined that BMAL1 directs the circadian expression of many genes implicated in cartilage homeostasis, including those involved in catabolic, anabolic, and apoptotic pathways. Loss of BMAL1 reduced the levels of phosphorylated SMAD2/3 (p-SMAD2/3) and NFATC2 and decreased expression of the major matrix-related genes Sox9, Acan, and Col2a1, but increased p-SMAD1/5 levels. Together, these results define a regulatory mechanism that links chondrocyte BMAL1 to the maintenance and repair of cartilage and suggest that circadian rhythm disruption is a risk factor for joint diseases such as OA. PMID:26657859

  6. Active skin perfusion and thermoregulatory response in the hand following nerve injury and repair in human upper extremities.

    PubMed

    Deng, Aidong; Liu, Dan; Gu, Chen; Gu, Xiaosong; Gu, Jianhui; Hu, Wen

    2016-01-01

    Cutaneous vasoconstriction/vasodilatation occurs in response to whole body and local cooling/heating, and the vasomotor activities play a pivotal role in thermal control of the human body. The mechanisms underlying regulation of skin blood flow involve both neurogenic and humeral/local chemical influence, contributing to the initial response to thermal stimuli and the prolonged phase of response, respectively. Previous studies have suggested the impairment of cutaneous thermal regulation after nerve injury. However, the evidence regarding how the skin perfusion and thermoregulatory response evolve after nerve injury and repair remains limited. Here we observed, by utilizing laser-Doppler perfusion imaging, baseline skin perfusion and perfusion change in response to thermal stimuli after median and ulnar nerve injury, and the results showed that baseline perfusion in autonomous skin area profoundly decreased and active rewarming after clod stress dramatically diminished before sensory recovery of the skin became detectable. In addition, baseline cutaneous perfusion was recovered as the skin regained touch sensation, and exhibited positive correlation to touch sensibility of the skin. These data indicate that both active perfusion and thermoregulatory response of the skin are markedly compromised during skin denervation and can be recovered by re-innervation. This suggests the importance of timely repair of injured nerve, especially in the practice of replantation. PMID:26529641

  7. Active skin perfusion and thermoregulatory response in the hand following nerve injury and repair in human upper extremities.

    PubMed

    Deng, Aidong; Liu, Dan; Gu, Chen; Gu, Xiaosong; Gu, Jianhui; Hu, Wen

    2016-01-01

    Cutaneous vasoconstriction/vasodilatation occurs in response to whole body and local cooling/heating, and the vasomotor activities play a pivotal role in thermal control of the human body. The mechanisms underlying regulation of skin blood flow involve both neurogenic and humeral/local chemical influence, contributing to the initial response to thermal stimuli and the prolonged phase of response, respectively. Previous studies have suggested the impairment of cutaneous thermal regulation after nerve injury. However, the evidence regarding how the skin perfusion and thermoregulatory response evolve after nerve injury and repair remains limited. Here we observed, by utilizing laser-Doppler perfusion imaging, baseline skin perfusion and perfusion change in response to thermal stimuli after median and ulnar nerve injury, and the results showed that baseline perfusion in autonomous skin area profoundly decreased and active rewarming after clod stress dramatically diminished before sensory recovery of the skin became detectable. In addition, baseline cutaneous perfusion was recovered as the skin regained touch sensation, and exhibited positive correlation to touch sensibility of the skin. These data indicate that both active perfusion and thermoregulatory response of the skin are markedly compromised during skin denervation and can be recovered by re-innervation. This suggests the importance of timely repair of injured nerve, especially in the practice of replantation.

  8. Nucleotide excision repair and response and survival to chemotherapy in colorectal cancer patients.

    PubMed

    Kap, Elisabeth J; Popanda, Odilia; Chang-Claude, Jenny

    2016-05-01

    Several new chemotherapeutic agents have become available for the treatment of colorectal cancer, which has led to increased complexity in treatment planning. Treatment decision making for individual patients could be facilitated if guided by predictive and prognostic markers. As most cytotoxic drugs induce DNA damage, the DNA damage repair pathways hold potential for yielding such biomarkers. Here, we review the current evidence of a possible involvement of the nucleotide excision repair pathway in the efficacy of chemotherapeutic agents used in the treatment of colorectal cancer. Although a large number of studies have been conducted, they are generally of moderate size and heterogeneous in design. Up to date no firm conclusions can be drawn to translate these results into the clinic. We recommend further comprehensive investigations of the nucleotide excision repair pathway in large patient studies that include both discovery and validation cohorts. PMID:27183147

  9. Fluorogenic Real-Time Reporters of DNA Repair by MGMT, a Clinical Predictor of Antitumor Drug Response

    PubMed Central

    Beharry, Andrew A.; Nagel, Zachary D.; Samson, Leona D.; Kool, Eric T.

    2016-01-01

    Common alkylating antitumor drugs, such as temozolomide, trigger their cytotoxicity by methylating the O6-position of guanosine in DNA. However, the therapeutic effect of these drugs is dampened by elevated levels of the DNA repair enzyme, O6-methylguanine DNA methyltransferase (MGMT), which directly reverses this alkylation. As a result, assessing MGMT levels in patient samples provides an important predictor of therapeutic response; however, current methods available to measure this protein are indirect, complex and slow. Here we describe the design and synthesis of fluorescent chemosensors that report directly on MGMT activity in a single step within minutes. The chemosensors incorporate a fluorophore and quencher pair, which become separated by the MGMT dealkylation reaction, yielding light-up responses of up to 55-fold, directly reflecting repair activity. Experiments show that the best-performing probe retains near-native activity at mid-nanomolar concentrations. A nuclease-protected probe, NR-1, was prepared and tested in tumor cell lysates, demonstrating an ability to evaluate relative levels of MGMT repair activity in twenty minutes. In addition, a probe was employed to evaluate inhibitors of MGMT, suggesting utility for discovering new inhibitors in a high-throughput manner. Probe designs such as that of NR-1 may prove valuable to clinicians in selection of patients for alkylating drug therapies and in assessing resistance that arises during treatment. PMID:27035132

  10. Changes in the deformational behavior of human hip cartilage with age.

    PubMed

    Armstrong, C G; Bahrani, A S; Gardner, D L

    1980-08-01

    The deformation occurring in the articular cartilage covering the human femoral head has been measured both when the femoral head is loaded in its natural acetabulum and when the cartilage is loaded with a small indentor. The results indicate that the material response is substantially different in these two situations. In the intact joint the cartilage deformation is substantially greater in older joints, but the response of cartilage to loading with an indentor does not change significantly with age. Theoretical elastic models of the cartilage behavior in these two situations were analyzed. For old cartilage which is idealized as an elastic material the increased deformation which is observed in the intact joint can be attributed to changes in Poisson's ratio, though in the real material increased fluid flux under load is the more probable cause.

  11. Regenerating cartilages by engineered ASCs: prolonged TGF-β3/BMP-6 expression improved articular cartilage formation and restored zonal structure.

    PubMed

    Lu, Chia-Hsin; Yeh, Tsung-Szu; Yeh, Chia-Lin; Fang, Yu-Hua Dean; Sung, Li-Yu; Lin, Shih-Yeh; Yen, Tzu-Chen; Chang, Yu-Han; Hu, Yu-Chen

    2014-01-01

    Adipose-derived stem cells (ASCs) hold promise for cartilage regeneration but their chondrogenesis potential is inferior. Here, we used a baculovirus (BV) system that exploited FLPo/Frt-mediated transgene recombination and episomal minicircle formation to genetically engineer rabbit ASCs (rASCs). The BV system conferred prolonged and robust TGF-β3/BMP-6 expression in rASCs cultured in porous scaffolds, which critically augmented rASCs chondrogenesis and suppressed osteogenesis/hypertrophy, leading to the formation of cartilaginous constructs with improved maturity and mechanical properties in 2-week culture. Twelve weeks after implantation into full-thickness articular cartilage defects in rabbits, these engineered constructs regenerated neocartilages that resembled native hyaline cartilages in cell morphology, matrix composition and mechanical properties. The neocartilages also displayed cartilage-specific zonal structures without signs of hypertrophy and degeneration, and eventually integrated with host cartilages. In contrast, rASCs that transiently expressed TGF-β3/BMP-6 underwent osteogenesis/hypertrophy and resulted in the formation of inferior cartilaginous constructs, which after implantation regenerated fibrocartilages. These data underscored the crucial role of TGF-β3/BMP-6 expression level and duration in rASCs in the cell differentiation, constructs properties and in vivo repair. The BV-engineered rASCs that persistently express TGF-β3/BMP-6 improved the chondrogenesis, in vitro cartilaginous constructs production and in vivo hyaline cartilage regeneration, thus representing a remarkable advance in cartilage engineering. PMID:23851345

  12. The incorporation of a zone of calcified cartilage improves the interfacial shear strength between in vitro-formed cartilage and the underlying substrate.

    PubMed

    St-Pierre, Jean-Philippe; Gan, Lu; Wang, Jian; Pilliar, Robert M; Grynpas, Marc D; Kandel, Rita A

    2012-04-01

    A major challenge for cartilage tissue engineering remains the proper integration of constructs with surrounding tissues in the joint. Biphasic osteochondral constructs that can be anchored in a joint through bone ingrowth partially address this requirement. In this study, a methodology was devised to generate a cell-mediated zone of calcified cartilage (ZCC) between the in vitro-formed cartilage and a porous calcium polyphosphate (CPP) bone substitute in an attempt to improve the mechanical integrity of that interface. To do so, a calcium phosphate (CaP) film was deposited on CPP by a sol-gel process to prevent the accumulation of polyphosphates and associated inhibition of mineralization as the substrate degrades. Cartilage formed in vitro on the top surface of CaP-coated CPP by deep-zone chondrocytes was histologically and biochemically comparable to that formed on uncoated CPP. Furthermore, the mineral in the ZCC was similar in crystal structure, morphology and length to that formed on uncoated CPP and native articular cartilage. The generation of a ZCC at the cartilage-CPP interface led to a 3.3-fold increase in the interfacial shear strength of biphasic constructs. Improved interfacial strength of these constructs may be critical to their clinical success for the repair of large cartilage defects.

  13. Phosphoramide mustard exposure induces DNA adduct formation and the DNA damage repair response in rat ovarian granulosa cells

    SciTech Connect

    Ganesan, Shanthi Keating, Aileen F.

    2015-02-01

    Phosphoramide mustard (PM), the ovotoxic metabolite of the anti-cancer agent cyclophosphamide (CPA), destroys rapidly dividing cells by forming NOR-G-OH, NOR-G and G-NOR-G adducts with DNA, potentially leading to DNA damage. A previous study demonstrated that PM induces ovarian DNA damage in rat ovaries. To investigate whether PM induces DNA adduct formation, DNA damage and induction of the DNA repair response, rat spontaneously immortalized granulosa cells (SIGCs) were treated with vehicle control (1% DMSO) or PM (3 or 6 μM) for 24 or 48 h. Cell viability was reduced (P < 0.05) after 48 h of exposure to 3 or 6 μM PM. The NOR-G-OH DNA adduct was detected after 24 h of 6 μM PM exposure, while the more cytotoxic G-NOR-G DNA adduct was formed after 48 h by exposure to both PM concentrations. Phosphorylated H2AX (γH2AX), a marker of DNA double stranded break occurrence, was also increased by PM exposure, coincident with DNA adduct formation. Additionally, induction of genes (Atm, Parp1, Prkdc, Xrcc6, and Brca1) and proteins (ATM, γH2AX, PARP-1, PRKDC, XRCC6, and BRCA1) involved in DNA repair were observed in both a time- and dose-dependent manner. These data support that PM induces DNA adduct formation in ovarian granulosa cells, induces DNA damage and elicits the ovarian DNA repair response. - Highlights: • PM forms ovarian DNA adducts. • DNA damage marker γH2AX increased by PM exposure. • PM induces ovarian DNA double strand break repair.

  14. Three-dimensional polycaprolactone-hydroxyapatite scaffolds combined with bone marrow cells for cartilage tissue engineering.

    PubMed

    Wei, Bo; Yao, Qingqiang; Guo, Yang; Mao, Fengyong; Liu, Shuai; Xu, Yan; Wang, Liming

    2015-08-01

    The goal of this study was to investigate the chondrogenic potential of three-dimensional polycaprolactone-hydroxyapatite (PCL-HA) scaffolds loaded with bone marrow cells in vitro and the effect of PCL-HA scaffolds on osteochondral repair in vivo. Here, bone marrow was added to the prepared PCL-HA scaffolds and cultured in chondrogenic medium for 10 weeks. Osteochondral defects were created in the trochlear groove of 29 knees in 17 New Zealand white rabbits, which were then divided into four groups that underwent: implantation of PCL-HA scaffolds (left knee, n = 17; Group 1), microfracture (right knee, n = 6; Group 2), autologous osteochondral transplantation (right knee, n = 6; Group 3), and no treatment (right knee, n = 5; Control). Extracellular matrix produced by bone marrow cells covered the surface and filled the pores of PCL-HA scaffolds after 10 weeks in culture. Moreover, many cell-laden cartilage lacunae were observed, and cartilage matrix was concentrated in the PCL-HA scaffolds. After a 12-week repair period, Group 1 showed excellent vertical and lateral integration with host bone, but incomplete cartilage regeneration and matrix accumulation. An uneven surface of regenerated cartilage and reduced distribution of cartilage matrix were observed in Group 2. In addition, abnormal bone growth and unstable integration between repaired and host tissues were detected. For Group 3, the integration between transplanted and host cartilage was interrupted. Our findings indicate that the PCL-HA scaffolds loaded with bone marrow cells improved chondrogenesis in vitro and implantation of PCL-HA scaffolds for osteochondral repairenhanced integration with host bone. However, cartilage regeneration remained unsatisfactory. The addition of trophic factors or the use of precultured cell-PCL-HA constructs for accelerated osteochondral repair requires further investigation.

  15. Mitosis, double strand break repair, and telomeres: a view from the end: how telomeres and the DNA damage response cooperate during mitosis to maintain genome stability.

    PubMed

    Cesare, Anthony J

    2014-11-01

    Double strand break (DSB) repair is suppressed during mitosis because RNF8 and downstream DNA damage response (DDR) factors, including 53BP1, do not localize to mitotic chromatin. Discovery of the mitotic kinase-dependent mechanism that inhibits DSB repair during cell division was recently reported. It was shown that restoring mitotic DSB repair was detrimental, resulting in repair dependent genome instability and covalent telomere fusions. The telomere DDR that occurs naturally during cellular aging and in cancer is known to be refractory to G2/M checkpoint activation. Such DDR-positive telomeres, and those that occur as part of the telomere-dependent prolonged mitotic arrest checkpoint, normally pass through mitosis without covalent ligation, but result in cell growth arrest in G1 phase. The discovery that suppressing DSB repair during mitosis may function primarily to protect DDR-positive telomeres from fusing during cell division reinforces the unique cooperation between telomeres and the DDR to mediate tumor suppression.

  16. Opposing roles of RNF8/RNF168 and deubiquitinating enzymes in ubiquitination-dependent DNA double-strand break response signaling and DNA-repair pathway choice

    PubMed Central

    Nakada, Shinichiro

    2016-01-01

    The E3 ubiquitin ligases ring finger protein (RNF) 8 and RNF168 transduce the DNA double-strand break (DSB) response (DDR) signal by ubiquitinating DSB sites. The depletion of RNF8 or RNF168 suppresses the accumulation of DNA-repair regulating factors such as 53BP1 and RAP80 at DSB sites, suggesting roles for RNF8- and RNF168-mediated ubiquitination in DSB repair. This mini-review provides a brief overview of the RNF8- and RNF168-dependent DDR-signaling and DNA-repair pathways. The choice of DNA-repair pathway when RNF8- and RNF168-mediated ubiquitination-dependent DDR signaling is negatively regulated by deubiquitinating enzymes (DUBs) is reviewed to clarify how the opposing roles of RNF8/RNF168 and DUBs regulate ubiquitination-dependent DDR signaling and the choice of DNA-repair pathway. PMID:26983989

  17. Epigenetics of cartilage diseases.

    PubMed

    Gabay, Odile; Clouse, Kathleen A

    2016-10-01

    Osteoarticular diseases, such as arthritis or osteoarthritis, are multifactorial diseases with an underlying genetic etiology that are challenging to study. Genome-Wide Association studies (GWAS) have identified several genetic loci associated with these diseases. Epigenetics is a complex mechanism of chromatin and gene modulation through DNA methylation, histone deacetylation or microRNA, which might contribute to the inheritability of disease. Some of these mechanisms have been studied for decades in other diseases or as part of the aging process, where epigenetic changes seem to play an important role. With the implementation of better technological tools, such as the Illumina next generation sequencing, altered methylation of DNA has been linked to articular diseases and these mechanisms have been shown to regulate metalloprotease (MMP) expression and cartilage matrix integrity. Some miRNA have also been identified and more extensively characterized, such as delineation of the role played by miR-140 in chondrogenesis, followed by the discovery of numerous miRNA potentially involved in the epigenetic regulation of osteoarthritic disease. Histone deacetylases have long been linked to aging, particularly with respect to the Sirtuin family with Sirt1 as the major player. Because aging is the major risk factor for osteoarthritis, the involvement of Sirtuins in the etiology of osteoarthritis has been suggested and investigated. All of these fine regulations together shed new light on cartilage disease pathophysiology. We present in this short review an update of the role of these pathways in articular diseases.

  18. In vitro cartilage tissue engineering with 3D porous aqueous-derived silk scaffolds and mesenchymal stem cells.

    PubMed

    Wang, Yongzhong; Kim, Ung-Jin; Blasioli, Dominick J; Kim, Hyeon-Joo; Kaplan, David L

    2005-12-01

    Adult cartilage tissue has limited self-repair capacity, especially in the case of severe damages caused by developmental abnormalities, trauma, or aging-related degeneration like osteoarthritis. Adult mesenchymal stem cells (MSCs) have the potential to differentiate into cells of different lineages including bone, cartilage, and fat. In vitro cartilage tissue engineering using autologous MSCs and three-dimensional (3-D) porous scaffolds has the potential for the successful repair of severe cartilage damage. Ideally, scaffolds designed for cartilage tissue engineering should have optimal structural and mechanical properties, excellent biocompatibility, controlled degradation rate, and good handling characteristics. In the present work, a novel, highly porous silk scaffold was developed by an aqueous process according to these criteria and subsequently combined with MSCs for in vitro cartilage tissue engineering. Chondrogenesis of MSCs in the silk scaffold was evident by real-time RT-PCR analysis for cartilage-specific ECM gene markers, histological and immunohistochemical evaluations of cartilage-specific ECM components. Dexamethasone and TGF-beta3 were essential for the survival, proliferation and chondrogenesis of MSCs in the silk scaffolds. The attachment, proliferation, and differentiation of MSCs in the silk scaffold showed unique characteristics. After 3 weeks of cultivation, the spatial cell arrangement and the collagen type-II distribution in the MSCs-silk scaffold constructs resembles those in native articular cartilage tissue, suggesting promise for these novel 3-D degradable silk-based scaffolds in MSC-based cartilage repair. Further in vivo evaluation is necessary to fully recognize the clinical relevance of these observations.

  19. Composite scaffolds for cartilage tissue engineering.

    PubMed

    Moutos, Franklin T; Guilak, Farshid

    2008-01-01

    Tissue engineering remains a promising therapeutic strategy for the repair or regeneration of diseased or damaged tissues. Previous approaches have typically focused on combining cells and bioactive molecules (e.g., growth factors, cytokines and DNA fragments) with a biomaterial scaffold that functions as a template to control the geometry of the newly formed tissue, while facilitating the attachment, proliferation, and differentiation of embedded cells. Biomaterial scaffolds also play a crucial role in determining the functional properties of engineered tissues, including biomechanical characteristics such as inhomogeneity, anisotropy, nonlinearity or viscoelasticity. While single-phase, homogeneous materials have been used extensively to create numerous types of tissue constructs, there continue to be significant challenges in the development of scaffolds that can provide the functional properties of load-bearing tissues such as articular cartilage. In an attempt to create more complex scaffolds that promote the regeneration of functional engineered tissues, composite scaffolds comprising two or more distinct materials have been developed. This paper reviews various studies on the development and testing of composite scaffolds for the tissue engineering of articular cartilage, using techniques such as embedded fibers and textiles for reinforcement, embedded solid structures, multi-layered designs, or three-dimensionally woven composite materials. In many cases, the use of composite scaffolds can provide unique biomechanical and biological properties for the development of functional tissue engineering scaffolds.

  20. A localized nucleolar DNA damage response facilitates recruitment of the homology-directed repair machinery independent of cell cycle stage

    PubMed Central

    van Sluis, Marjolein; McStay, Brian

    2015-01-01

    DNA double-strand breaks (DSBs) are repaired by two main pathways: nonhomologous end-joining and homologous recombination (HR). Repair pathway choice is thought to be determined by cell cycle timing and chromatin context. Nucleoli, prominent nuclear subdomains and sites of ribosome biogenesis, form around nucleolar organizer regions (NORs) that contain rDNA arrays located on human acrocentric chromosome p-arms. Actively transcribed rDNA repeats are positioned within the interior of the nucleolus, whereas sequences proximal and distal to NORs are packaged as heterochromatin located at the nucleolar periphery. NORs provide an opportunity to investigate the DSB response at highly transcribed, repetitive, and essential loci. Targeted introduction of DSBs into rDNA, but not abutting sequences, results in ATM-dependent inhibition of their transcription by RNA polymerase I. This is coupled with movement of rDNA from the nucleolar interior to anchoring points at the periphery. Reorganization renders rDNA accessible to repair factors normally excluded from nucleoli. Importantly, DSBs within rDNA recruit the HR machinery throughout the cell cycle. Additionally, unscheduled DNA synthesis, consistent with HR at damaged NORs, can be observed in G1 cells. These results suggest that HR can be templated in cis and suggest a role for chromosomal context in the maintenance of NOR genomic stability. PMID:26019174

  1. Enhanced microfracture techniques in cartilage knee surgery: Fact or fiction?

    PubMed

    Bark, Stefan; Piontek, Tomasz; Behrens, Peter; Mkalaluh, Sabreen; Varoga, Deike; Gille, Justus

    2014-09-18

    The limited intrinsic healing potential of human articular cartilage is a well-known problem in orthopedic surgery. Thus a variety of surgical techniques have been developed to reduce joint pain, improve joint function and delay the onset of osteoarthritis. Microfractures as a bone marrow stimulation technique present the most common applied articular cartilage repair procedure today. Unfortunately the deficiencies of fibrocartilaginous repair tissue inevitably lead to breakdown under normal joint loading and clinical results deteriorate with time. To overcome the shortcomings of microfracture, an enhanced microfracture technique was developed with an additional collagen I/III membrane (Autologous, Matrix-Induced Chondrogenesis, AMIC(®)). This article reviews the pre-clinical rationale of microfractures and AMIC(®), presents clinical studies and shows the advantages and disadvantages of these widely used techniques. PubMed and the Cochrane database were searched to identify relevant studies. We used a comprehensive search strategy with no date or language restrictions to locate studies that examined the AMIC(®) technique and microfracture. Search keywords included cartilage, microfracture, AMIC(®), knee, Chondro-Gide(®). Besides this, we included our own experiences and study authors were contacted if more and non published data were needed. Both cartilage repair techniques represent an effective and safe method of treating full-thickness chondral defects of the knee in selected cases. While results after microfracture deteriorate with time, mid-term results after AMIC(®) seem to be enduring. Randomized studies with long-term follow-up are needed whether the grafted area will maintain functional improvement and structural integrity over time.

  2. Neonatal desensitization supports long-term survival and functional integration of human embryonic stem cell-derived mesenchymal stem cells in rat joint cartilage without immunosuppression.

    PubMed

    Zhang, Shufang; Jiang, Yang Zi; Zhang, Wei; Chen, Longkun; Tong, Tong; Liu, Wanlu; Mu, Qin; Liu, Hua; Ji, Junfeng; Ouyang, Hong Wei; Zou, Xiaohui

    2013-01-01

    Immunological response hampers the investigation of human embryonic stem cells (hESCs) or their derivates for tissue regeneration in vivo. Immunosuppression is often used after surgery, but exhibits side effects of significant weight loss and allows only short-term observation. The purpose of this study was to investigate whether neonatal desensitization supports relative long-term survival of hESC-derived mesenchymal stem cells (hESC-MSCs) and promotes cartilage regeneration. hESC-MSCs were injected on the day of birth in rats. Six weeks after neonatal injection, a full-thickness cylindrical cartilage defect was created and transplanted with a hESC-MSC-seeded collagen bilayer scaffold (group d+s+c) or a collagen bilayer scaffold (group d+s). Rats without neonatal injection were transplanted with the hESC-MSC-seeded collagen bilayer scaffold to serve as controls (group s+c). Cartilage regeneration was evaluated by histological analysis, immunohistochemical staining, and biomechanical test. The role of hESC-MSCs in cartilage regeneration was analyzed by CD4 immunostaining, cell death detection, and visualization of human cells in regenerated tissues. hESC-MSCs expressed CD105, CD73, CD90, CD29, and CD44, but not CD45 and CD34, and possessed trilineage differentiation potential. Group d+s+c exhibited greater International Cartilage Repair Society (ICRS) scores than group d+s or group s+c. Abundant collagen type II and improved mechanical properties were detected in group d+s+c. There were less CD4+ inflammatory cell infiltration and cell death at week 1, and hESC-MSCs were found to survive as long as 8 weeks after transplantation in group d+s+c. Our study suggests that neonatal desensitization before transplantation may be an efficient way to develop a powerful tool for preclinical study of human cell-based therapies in animal models.

  3. Cartilage nominal strain correlates with shear modulus and glycosaminoglycans content in meniscectomized joints.

    PubMed

    Song, Yongnam; Carter, Dennis R; Giori, Nicholas J

    2014-06-01

    Postmeniscectomy osteoarthritis (OA) is hypothesized to be the consequence of abnormal mechanical conditions, but the relationship between postsurgical alterations in articular cartilage strain and in vivo biomechanical/biochemical changes in articular cartilage is unclear. We hypothesized that spatial variations in cartilage nominal strain (percentile thickness change) would correlate with previously reported in vivo articular cartilage property changes following meniscectomy. Cadevaric sheep knees were loaded in cyclic compression which was previously developed to mimic normal sheep gait, while a 4.7 T magnetic resonance imaging (MRI) imaged the whole joint. 3D cartilage strain maps were compared with in vivo sheep studies that described postmeniscectomy changes in shear modulus, phase lag, proteoglycan content and collagen organization/content in the articular cartilage. The area of articular cartilage experiencing high (overloaded) and low (underloaded) strain was significantly increased in the meniscectomized tibial compartment by 10% and 25%, respectively, while no significant changes were found in the nonmeniscectomized compartment. The overloaded and underloaded regions of articular cartilage in our in vitro specimens correlated with regions of in vivo shear modulus reduction. Glycosaminoglycans (GAG) content only increased at the underloaded articular cartilage but decreased at the overloaded articular cartilage. No significant correlation was found in phase lag and collagen organization/content changes with the strain variation. Comparisons between postsurgical nominal strain and in vivo cartilage property changes suggest that both overloading and underloading after meniscectomy may directly damage the cartilage matrix stiffness (shear modulus). Disruption of superficial cartilage by overloading might be responsible for the proteoglycan (GAG) loss in the early stage of postmeniscectomy OA. PMID:24671447

  4. [The German Cartilage Registry (KnorpelRegister DGOU) for evaluation of surgical treatment for cartilage defects: experience after six months including first demographic data].

    PubMed

    Niemeyer, P; Schweigler, K; Grotejohann, B; Maurer, J; Angele, P; Aurich, M; Becher, C; Fay, J; Feil, R; Fickert, S; Fritz, J; Hoburg, A; Kreuz, P; Kolombe, T; Laskowski, J; Lützner, J; Marlovits, S; Müller, P E; Niethammer, T; Pietschmann, M; Ruhnau, K; Spahn, G; Tischer, T; Zinser, W; Albrecht, D

    2015-02-01

    The German Cartilage Registry (KnorpelRegister DGOU) has been introduced in October 2013 and aims on the evaluation of patients who underwent cartilage repair for symptomatic cartilage defects. It represents a nation-wide cohort study which has been introduced by the working group "Tissue Regeneration" of the Germany Society of Orthopaedic Surgery and Traumatology and is technically based upon a web-based remote data entry (RDE) system. The present article describes first experiences with the registry including patient and treatment characteristics. Between October 2013 and April 2014, a total of 230 patients who had undergone surgical cartilage repair for symptomatic full-thickness cartilage defects of the knee has been included in the German Cartilage Registry from 23 cartilage repair centres. Mean age was 37.11 years (SD 13.61) and mean defect size was 3.68 cm(2) (SD 0.23). Since the introduction of the KnorpelRegister DGOU the total number of registered patients has increased steadily up to the most recent figure of 72 patients within one month. Patients were treated mainly according to the recommended therapies. The highest percentage in therapy is represented by the bone marrow stimulation techniques (55.02 %) as well as by the autologous chondrocyte transplantation (34.92 %). Unlike the patient collective in the majority of prospective randomised controlled trials, the patient population within the registry shows a high proportion of patients with accompanying pathologies, with an age of more than 50 years at the time of treatment and with unfavourably assessed accompanying pathologies such as an affection of the opposite cartilage surface or a previously resected meniscus. In summary, the technical platform and forms of documentation of the KnorpelRegister DGOU have proved to be very promising within the first six months. Unlike data from other clinical trials, the previous analysis of the patients' data and therapies reflects successfully the actual

  5. ADAMTS-12 Associates with and Degrades Cartilage Oligomeric Matrix Protein*

    PubMed Central

    Liu, Chuan-ju; Kong, Wei; Xu, Ke; Luan, Yi; Ilalov, Kiril; Sehgal, Bantoo; Yu, Shuang; Howell, Ronald D.; Cesare, Paul E. Di

    2006-01-01

    Loss of articular cartilage because of extracellular matrix breakdown is the hallmark of arthritis. Degradative fragments of cartilage oligomeric matrix protein (COMP), a prominent noncollagenous matrix component in articular cartilage, have been observed in the cartilage, synovial fluid, and serum of arthritis patients. The molecular mechanism of COMP degradation and the enzyme(s) responsible for it, however, remain largely unknown. ADAMTS-12 (a disintegrin and metalloprotease with thrombospondin motifs) was shown to associate with COMP both in vitro and in vivo. ADAMTS-12 selectively binds to only the epidermal growth factor-like repeat domain of COMP of the four functional domains tested. The four C-terminal TSP-1-like repeats of ADAMTS-12 are shown to be necessary and sufficient for its interaction with COMP. Recombinant ADAMTS-12 is capable of digesting COMP in vitro. The COMP-degrading activity of ADAMTS-12 requires the presence of Zn2+ and appropriate pH (7.5-9.5), and the level of ADAMTS-12 in the cartilage and synovium of patients with both osteoarthritis and rheumatoid arthritis is significantly higher than in normal cartilage and synovium. Together, these findings indicate that ADAMTS-12 is a new COMP-interacting and -degrading enzyme and thus may play an important role in the COMP degradation in the initiation and progression of arthritis. PMID:16611630

  6. Site-1 protease is required for cartilage development in zebrafish.

    PubMed

    Schlombs, Kornelia; Wagner, Thomas; Scheel, Jochen

    2003-11-25

    gonzo (goz) is a zebrafish mutant with defects in cartilage formation. The goz phenotype comprises cartilage matrix defects and irregular chondrocyte morphology. Expression of endoderm, mesoderm, and cartilage marker genes is, however, normal, indicating a defect in chondrocyte morphogenesis. The mutated gene responsible for the goz phenotype, identified by positional cloning and confirmed by phosphomorpholino knockdown, encodes zebrafish site-1 protease (s1p). S1P has been shown to process and activate sterol regulatory element-binding proteins (SREBPs), which regulate expression of key enzymes of lipid biosynthesis or transport. This finding is consistent with the abnormal distribution of lipids in goz embryos. Knockdown of site-2 protease, which is also involved in activation of SREBPs, results in similar lipid and cartilage phenotypes as S1P knockdown. However, knockdown of SREBP cleavage-activating protein, which forms a complex with SREBP and is essential for S1P cleavage, results only in lipid phenotypes, whereas cartilage appears normal. This indicates that the cartilage phenoptypes of goz are caused independently of the lipid defects. PMID:14612568

  7. Site-1 protease is required for cartilage development in zebrafish

    PubMed Central

    Schlombs, Kornelia; Wagner, Thomas; Scheel, Jochen

    2003-01-01

    gonzo (goz) is a zebrafish mutant with defects in cartilage formation. The goz phenotype comprises cartilage matrix defects and irregular chondrocyte morphology. Expression of endoderm, mesoderm, and cartilage marker genes is, however, normal, indicating a defect in chondrocyte morphogenesis. The mutated gene responsible for the goz phenotype, identified by positional cloning and confirmed by phosphomorpholino knockdown, encodes zebrafish site-1 protease (s1p). S1P has been shown to process and activate sterol regulatory element-binding proteins (SREBPs), which regulate expression of key enzymes of lipid biosynthesis or transport. This finding is consistent with the abnormal distribution of lipids in goz embryos. Knockdown of site-2 protease, which is also involved in activation of SREBPs, results in similar lipid and cartilage phenotypes as S1P knockdown. However, knockdown of SREBP cleavage-activating protein, which forms a complex with SREBP and is essential for S1P cleavage, results only in lipid phenotypes, whereas cartilage appears normal. This indicates that the cartilage phenoptypes of goz are caused independently of the lipid defects. PMID:14612568

  8. Superabsorbent 3D Scaffold Based on Electrospun Nanofibers for Cartilage Tissue Engineering.

    PubMed

    Chen, Weiming; Chen, Shuai; Morsi, Yosry; El-Hamshary, Hany; El-Newhy, Mohamed; Fan, Cunyi; Mo, Xiumei

    2016-09-21

    Electrospun nanofibers have been used for various biomedical applications. However, electrospinning commonly produces two-dimensional (2D) membranes, which limits the application of nanofibers for the 3D tissue engineering scaffold. In the present study, a porous 3D scaffold (3DS-1) based on electrospun gelatin/PLA nanofibers has been prepared for cartilage tissue regeneration. To further improve the repairing effect of cartilage, a modified scaffold (3DS-2) cross-linked with hyaluronic acid (HA) was also successfully fabricated. The nanofibrous structure, water absorption, and compressive mechanical properties of 3D scaffold were studied. Chondrocytes were cultured on 3D scaffold, and their viability and morphology were examined. 3D scaffolds were also subjected to an in vivo cartilage regeneration study on rabbits using an articular cartilage injury model. The results indicated that 3DS-1 and 3DS-2 exhibited superabsorbent property and excellent cytocompatibility. Both these scaffolds present elastic property in the wet state. An in vivo study showed that 3DS-2 could enhance the repair of cartilage. The present 3D nanofibrous scaffold (3DS-2) would be promising for cartilage tissue engineering application. PMID:27559926

  9. Human Adipose-Derived Mesenchymal Progenitor Cells Engraft into Rabbit Articular Cartilage

    PubMed Central

    Wang, Wen; He, Na; Feng, Chenchen; Liu, Victor; Zhang, Luyi; Wang, Fei; He, Jiaping; Zhu, Tengfang; Wang, Shuyang; Qiao, Weiwei; Li, Suke; Zhou, Guangdong; Zhang, Li; Dai, Chengxiang; Cao, Wei

    2015-01-01

    Mesenchymal stem cells (MSCs) are known to have the potential for articular cartilage regeneration, and are suggested for the treatment of osteoarthritis (OA). Here, we investigated whether intra-articular injection of xenogeneic human adipose-derived mesenchymal progenitor cells (haMPCs) promoted articular cartilage repair in rabbit OA model and engrafted into rabbit articular cartilage. The haMPCs were cultured in vitro, and phenotypes and differentiation characteristics of cells were evaluated. OA was induced surgically by anterior cruciate ligament transection (ACLT) and medical meniscectomy of knee joints. At six weeks following surgery, hyaluronic acid (HA) or haMPCs was injected into the knee joints, the contralateral knee served as normal control. All animals were sacrificed at the 16th week post-surgery. Assessments were carried out by macroscopic examination, hematoxylin/eosin (HE) and Safranin-O/Fast green stainings and immunohistochemistry. The data showed that haMPC treatment promoted cartilage repair. Signals of human mitochondrial can be directly detected in haMPC treated cartilage. The haMPCs expressed human leukocyte antigen I (HLA-I) but not HLA-II-DR in vivo. These results suggest that intra-articular injection of haMPCs promotes regeneration of articular cartilage in rabbit OA model, and support the notion that MPCs are transplantable between HLA-incompatible individuals. PMID:26023716

  10. Superabsorbent 3D Scaffold Based on Electrospun Nanofibers for Cartilage Tissue Engineering.

    PubMed

    Chen, Weiming; Chen, Shuai; Morsi, Yosry; El-Hamshary, Hany; El-Newhy, Mohamed; Fan, Cunyi; Mo, Xiumei

    2016-09-21

    Electrospun nanofibers have been used for various biomedical applications. However, electrospinning commonly produces two-dimensional (2D) membranes, which limits the application of nanofibers for the 3D tissue engineering scaffold. In the present study, a porous 3D scaffold (3DS-1) based on electrospun gelatin/PLA nanofibers has been prepared for cartilage tissue regeneration. To further improve the repairing effect of cartilage, a modified scaffold (3DS-2) cross-linked with hyaluronic acid (HA) was also successfully fabricated. The nanofibrous structure, water absorption, and compressive mechanical properties of 3D scaffold were studied. Chondrocytes were cultured on 3D scaffold, and their viability and morphology were examined. 3D scaffolds were also subjected to an in vivo cartilage regeneration study on rabbits using an articular cartilage injury model. The results indicated that 3DS-1 and 3DS-2 exhibited superabsorbent property and excellent cytocompatibility. Both these scaffolds present elastic property in the wet state. An in vivo study showed that 3DS-2 could enhance the repair of cartilage. The present 3D nanofibrous scaffold (3DS-2) would be promising for cartilage tissue engineering application.

  11. Repair and cell cycle response in cells exposed to environmental biohazards. Progress report, June 1, 1979-May 31, 1980

    SciTech Connect

    Billen, D.; Hadden, C.T.

    1980-01-01

    Progress is reported in the following research areas: (1) DNA repair in Bacillus subtilis; (2) postreplication repair in Rec/sup -/ mutants of B. subtilis; (3) photobiology of halogenated DNA; (4) effects of caffeine on pyrimidine dimer excision and postreplication repair in B. subtilis; and (5) DNA repair in toluene-treated Escherichia coli. (ACR)

  12. Mechanical Testing of Hydrogels in Cartilage Tissue Engineering: Beyond the Compressive Modulus

    PubMed Central

    Xiao, Yinghua; Friis, Elizabeth A.; Gehrke, Stevin H.

    2013-01-01

    Injuries to articular cartilage result in significant pain to patients and high medical costs. Unfortunately, cartilage repair strategies have been notoriously unreliable and/or complex. Biomaterial-based tissue-engineering strategies offer great promise, including the use of hydrogels to regenerate articular cartilage. Mechanical integrity is arguably the most important functional outcome of engineered cartilage, although mechanical testing of hydrogel-based constructs to date has focused primarily on deformation rather than failure properties. In addition to deformation testing, as the field of cartilage tissue engineering matures, this community will benefit from the addition of mechanical failure testing to outcome analyses, given the crucial clinical importance of the success of engineered constructs. However, there is a tremendous disparity in the methods used to evaluate mechanical failure of hydrogels and articular cartilage. In an effort to bridge the gap in mechanical testing methods of articular cartilage and hydrogels in cartilage regeneration, this review classifies the different toughness measurements for each. The urgency for identifying the common ground between these two disparate fields is high, as mechanical failure is ready to stand alongside stiffness as a functional design requirement. In comparing toughness measurement methods between hydrogels and cartilage, we recommend that the best option for evaluating mechanical failure of hydrogel-based constructs for cartilage tissue engineering may be tensile testing based on the single edge notch test, in part because specimen preparation is more straightforward and a related American Society for Testing and Materials (ASTM) standard can be adopted in a fracture mechanics context. PMID:23448091

  13. A biophysical model of cell evolution after cytotoxic treatments: Damage, repair and cell response.

    PubMed

    Tomezak, M; Abbadie, C; Lartigau, E; Cleri, F

    2016-01-21

    We present a theoretical agent-based model of cell evolution under the action of cytotoxic treatments, such as radiotherapy or chemotherapy. The major features of cell cycle and proliferation, cell damage and repair, and chemical diffusion are included. Cell evolution is based on a discrete Markov chain, with cells stepping along a sequence of discrete internal states from 'normal' to 'inactive'. Probabilistic laws are introduced for each type of event a cell can undergo during its life: duplication, arrest, senescence, damage, reparation, or death. We adjust the model parameters on a series of cell irradiation experiments, carried out in a clinical LINAC, in which the damage and repair kinetics of single- and double-strand breaks are followed. Two showcase applications of the model are then presented. In the first one, we reconstruct the cell survival curves from a number of published low- and high-dose irradiation experiments. We reobtain a very good description of the data without assuming the well-known linear-quadratic model, but instead including a variable DSB repair probability. The repair capability of the model spontaneously saturates to an exponential decay at increasingly high doses. As a second test, we attempt to simulate the two extreme possibilities of the so-called 'bystander' effect in radiotherapy: the 'local' effect versus a 'global' effect, respectively activated by the short-range or long-range diffusion of some factor, presumably secreted by the irradiated cells. Even with an oversimplified simulation, we could demonstrate a sizeable difference in the proliferation rate of non-irradiated cells, the proliferation acceleration being much larger for the global than the local effect, for relatively small fractions of irradiated cells in the colony.

  14. Expression of DNA repair and metabolic genes in response to a flavonoid-rich diet.

    PubMed

    Guarrera, Simonetta; Sacerdote, Carlotta; Fiorini, Laura; Marsala, Rosa; Polidoro, Silvia; Gamberini, Sara; Saletta, Federica; Malaveille, Christian; Talaska, Glenn; Vineis, Paolo; Matullo, Giuseppe

    2007-09-01

    A diet rich in fruit and vegetables can be effective in the reduction of oxidative stress, through the antioxidant effects of phytochemicals and other mechanisms. Protection against the carcinogenic effects of chemicals may also be exerted by an enhancement of detoxification and DNA damage repair mechanisms. To investigate a putative effect of flavonoids, a class of polyphenols, on the regulation of the gene expression of DNA repair and metabolic genes, a 1-month flavonoid-rich diet was administered to thirty healthy male smokers, nine of whom underwent gene expression analysis. We postulated that tobacco smoke is a powerful source of reactive oxygen species. The expression level of twelve genes (APEX, ERCC1, ERCC2, ERCC4, MGMT, OGG1, XPA, XPC, XRCC1, XRCC3, AHR, CYP1A1) was investigated. We found a significant increase (P < 0.001) in flavonoid intake. Urinary phenolic content and anti-mutagenicity did not significantly change after diet, nor was a correlation found between flavonoid intake and urinary phenolic levels or anti-mutagenicity. Phenolic levels showed a significant positive correlation with urinary anti-mutagenicity. AHR levels were significantly reduced after the diet (P = 0.038), whereas the other genes showed a generalized up regulation, significant for XRCC3 gene (P = 0.038). Also in the context of a generalized up regulation of DNA repair genes, we found a non-significant negative correlation between flavonoid intake and the expression of all the DNA repair genes. Larger studies are needed to clarify the possible effects of flavonoids in vivo; our preliminary results could help to better plan new studies on gene expression and diet.

  15. Acinetobacter baumannii RecA Protein in Repair of DNA Damage, Antimicrobial Resistance, General Stress Response, and Virulence ▿

    PubMed Central

    Aranda, Jesús; Bardina, Carlota; Beceiro, Alejandro; Rumbo, Soraya; Cabral, Maria P.; Barbé, Jordi; Bou, Germán

    2011-01-01

    RecA is the major enzyme involved in homologous recombination and plays a central role in SOS mutagenesis. In Acinetobacter spp., including Acinetobacter baumannii , a multidrug-resistant bacterium responsible for nosocomial infections worldwide, DNA repair responses differ in many ways from those of other bacterial species. In this work, the function of A. baumannii RecA was examined by constructing a recA mutant. Alteration of this single gene had a pleiotropic effect, showing the involvement of RecA in DNA damage repair and consequently in cellular protection against stresses induced by DNA damaging agents, several classes of antibiotics, and oxidative agents. In addition, the absence of RecA decreased survival in response to both heat shock and desiccation. Virulence assays in vitro (with macrophages) and in vivo (using a mouse model) similarly implicated RecA in the pathogenicity of A. baumannii . Thus, the data strongly suggest a protective role for RecA in the bacterium and indicate that inactivation of the protein can contribute to a combined therapeutic approach to controlling A. baumannii infections. PMID:21642465

  16. FTIR-I compositional mapping of the cartilage-to-bone interface as a function of tissue region and age.

    PubMed

    Khanarian, Nora T; Boushell, Margaret K; Spalazzi, Jeffrey P; Pleshko, Nancy; Boskey, Adele L; Lu, Helen H

    2014-12-01

    Soft tissue-to-bone transitions, such as the osteochondral interface, are complex junctions that connect multiple tissue types and are critical for musculoskeletal function. The osteochondral interface enables pressurization of articular cartilage, facilitates load transfer between cartilage and bone, and serves as a barrier between these two distinct tissues. Presently, there is a lack of quantitative understanding of the matrix and mineral distribution across this multitissue transition. Moreover, age-related changes at the interface with the onset of skeletal maturity are also not well understood. Therefore, the objective of this study is to characterize the cartilage-to-bone transition as a function of age, using Fourier transform infrared spectroscopic imaging (FTIR-I) analysis to map region-dependent changes in collagen, proteoglycan, and mineral distribution, as well as collagen organization. Both tissue-dependent and age-related changes were observed, underscoring the role of postnatal physiological loading in matrix remodeling. It was observed that the relative collagen content increased continuously from cartilage to bone, whereas proteoglycan peaked within the deep zone of cartilage. With age, collagen content across the interface increased, accompanied by a higher degree of collagen alignment in both the surface and deep zone cartilage. Interestingly, regardless of age, mineral content increased exponentially across the calcified cartilage interface. These observations reveal new insights into both region- and age-dependent changes across the cartilage-to-bone junction and will serve as critical benchmark parameters for current efforts in integrative cartilage repair.

  17. FTIR-I Compositional Mapping of the Cartilage-to-Bone Interface as a Function of Tissue Region and Age

    PubMed Central

    Khanarian, Nora T; Boushell, Margaret K; Spalazzi, Jeffrey P; Pleshko, Nancy; Boskey, Adele L; Lu, Helen H

    2016-01-01

    Soft tissue-to-bone transitions, such as the osteochondral interface, are complex junctions that connect multiple tissue types and are critical for musculoskeletal function. The osteochondral interface enables pressurization of articular cartilage, facilitates load transfer between cartilage and bone, and serves as a barrier between these two distinct tissues. Presently, there is a lack of quantitative understanding of the matrix and mineral distribution across this multitissue transition. Moreover, age-related changes at the interface with the onset of skeletal maturity are also not well understood. Therefore, the objective of this study is to characterize the cartilage-to-bone transition as a function of age, using Fourier transform infrared spectroscopic imaging (FTIR-I) analysis to map region-dependent changes in collagen, proteoglycan, and mineral distribution, as well as collagen organization. Both tissue-dependent and age-related changes were observed, underscoring the role of postnatal physiological loading in matrix remodeling. It was observed that the relative collagen content increased continuously from cartilage to bone, whereas proteoglycan peaked within the deep zone of cartilage. With age, collagen content across the interface increased, accompanied by a higher degree of collagen alignment in both the surface and deep zone cartilage. Interestingly, regardless of age, mineral content increased exponentially across the calcified cartilage interface. These observations reveal new insights into both region- and age-dependent changes across the cartilage-to-bone junction and will serve as critical benchmark parameters for current efforts in integrative cartilage repair. PMID:24839262

  18. Near Infrared Spectroscopic Evaluation Of Water In Hyaline Cartilage

    PubMed Central

    Padalkar, MV; Spencer, RG; Pleshko, N

    2013-01-01

    In diseased conditions of cartilage such as osteoarthritis, there is typically an increase in water content from the average normal of 60–85% to greater than 90%. As cartilage has very little capability for self-repair, methods of early detection of degeneration are required, and assessment of water could prove to be a useful diagnostic method. Current assessment methods are either destructive, time consuming or have limited sensitivity. Here, we investigated the hypotheses that non-destructive near infrared spectroscopy (NIRS) of articular cartilage can be used to differentiate between free and bound water, and to quantitatively assess water content. The absorbances centered at 5200 cm−1 and 6890 cm−1 were attributed to a combination of free and bound water, and to free water only, respectively. The integrated areas of both absorbance bands were found to correlate linearly with the absolute water content (R=0.87 and R= 0.86) and with percent water content (R=0.97 and R=0.96) of the tissue. Partial least square models were also successfully developed and were used to predict water content, and percent free water. These data demonstrate that NIRS can be utilized to quantitatively determine water content in articular cartilage, and may aid in early detection of degenerative tissue changes in a laboratory setting, and with additional validations, possibly in a clinical setting. PMID:23824216

  19. Collagen VI enhances cartilage tissue generation by stimulating chondrocyte proliferation.

    PubMed

    Smeriglio, Piera; Dhulipala, Lakshmi; Lai, Janice H; Goodman, Stuart B; Dragoo, Jason L; Smith, Robert L; Maloney, William J; Yang, Fan; Bhutani, Nidhi

    2015-02-01

    Regeneration of human cartilage is inherently inefficient. Current cell-based approaches for cartilage repair, including autologous chondrocytes, are limited by the paucity of cells, associated donor site morbidity, and generation of functionally inferior fibrocartilage rather than articular cartilage. Upon investigating the role of collagen VI (Col VI), a major component of the chondrocyte pericellular matrix (PCM), we observe that soluble Col VI stimulates chondrocyte proliferation. Interestingly, both adult and osteoarthritis chondrocytes respond to soluble Col VI in a similar manner. The proliferative effect is, however, strictly due to the soluble Col VI as no proliferation is observed upon exposure of chondrocytes to immobilized Col VI. Upon short Col VI treatment in 2D monolayer culture, chondrocytes maintain high expression of characteristic chondrocyte markers like Col2a1, agc, and Sox9 whereas the expression of the fibrocartilage marker Collagen I (Col I) and of the hypertrophy marker Collagen X (Col X) is minimal. Additionally, Col VI-expanded chondrocytes show a similar potential to untreated chondrocytes in engineering cartilage in 3D biomimetic hydrogel constructs. Our study has, therefore, identified soluble Col VI as a biologic that can be useful for the expansion and utilization of scarce sources of chondrocytes, potentially for autologous chondrocyte implantation. Additionally, our results underscore the importance of further investigating the changes in chondrocyte PCM with age and disease and the subsequent effects on chondrocyte growth and function.

  20. A Semi-Degradable Composite Scaffold for Articular Cartilage Defects

    PubMed Central

    Scholten, Paul M.; Ng, Kenneth W.; Joh, Kiwon; Serino, Lorenzo P.; Warren, Russell F.; Torzilli, Peter A.; Maher, Suzanne A.

    2010-01-01

    Few options exist to replace or repair damaged articular cartilage. The optimal solution that has been suggested is a scaffold that can carry load and integrate with surrounding tissues; but such a construct has thus far been elusive. The objectives of this study were to manufacture and characterize a non-degradable hydrated scaffold. Our hypothesis was that the polymer content of the scaffold can be used to control its mechanical properties, while an internal porous network augmented with biological agents can facilitate integration with the host tissue. Using a two-step water-in-oil emulsion process a porous poly-vinyl alcohol (PVA) hydrogel scaffold combined with alginate microspheres was manufactured. The scaffold had a porosity of 11–30% with pore diameters of 107–187 μm, which readily allowed for movement of cells through the scaffold. Alginate microparticles were evenly distributed through the scaffold and allowed for the slow release of biological factors. The elastic modulus (Es) and Poisson’s ratio (υ), Aggregate modulus (Ha) and dynamic modulus (ED) of the scaffold were significantly affected by % PVA, as it varied from 10% to 20% wt/vol. Es and υ were similar to that of articular cartilage for both polymer concentrations, while Ha and ED were similar to that of cartilage only at 20% PVA. The ability to control scaffold mechanical properties, while facilitating cellular migration suggest that this scaffold is a potentially viable candidate for the functional replacement of cartilage defects. PMID:21308980

  1. Stem cells catalyze cartilage formation by neonatal articular chondrocytes in 3D biomimetic hydrogels

    NASA Astrophysics Data System (ADS)

    Lai, Janice H.; Kajiyama, Glen; Smith, Robert Lane; Maloney, William; Yang, Fan

    2013-12-01

    Cartilage loss is a leading cause of disability among adults and effective therapy remains elusive. Neonatal chondrocytes (NChons) are an attractive allogeneic cell source for cartilage repair, but their clinical translation has been hindered by scarce donor availability. Here we examine the potential for catalyzing cartilage tissue formation using a minimal number of NChons by co-culturing them with adipose-derived stem cells (ADSCs) in 3D hydrogels. Using three different co-culture models, we demonstrated that the effects of co-culture on cartilage tissue formation are dependent on the intercellular distance and cell distribution in 3D. Unexpectedly, increasing ADSC ratio in mixed co-culture led to increased synergy between NChons and ADSCs, and resulted in the formation of large neocartilage nodules. This work raises the potential of utilizing stem cells to catalyze tissue formation by neonatal chondrocytes via paracrine signaling, and highlights the importance of controlling cell distribution in 3D matrices to achieve optimal synergy.

  2. Gelatin Scaffolds with Controlled Pore Structure and Mechanical Property for Cartilage Tissue Engineering.

    PubMed

    Chen, Shangwu; Zhang, Qin; Nakamoto, Tomoko; Kawazoe, Naoki; Chen, Guoping

    2016-03-01

    Engineering of cartilage tissue in vitro using porous scaffolds and chondrocytes provides a promising approach for cartilage repair. However, nonuniform cell distribution and heterogeneous tissue formation together with weak mechanical property of in vitro engineered cartilage limit their clinical application. In this study, gelatin porous scaffolds with homogeneous and open pores were prepared using ice particulates and freeze-drying. The scaffolds were used to culture bovine articular chondrocytes to engineer cartilage tissue in vitro. The pore structure and mechanical property of gelatin scaffolds could be well controlled by using different ratios of ice particulates to gelatin solution and different concentrations of gelatin. Gelatin scaffolds prepared from ≥70% ice particulates enabled homogeneous seeding of bovine articular chondrocytes throughout the scaffolds and formation of homogeneous cartilage extracellular matrix. While soft scaffolds underwent cellular contraction, stiff scaffolds resisted cellular contraction and had significantly higher cell proliferation and synthesis of sulfated glycosaminoglycan. Compared with the gelatin scaffolds prepared without ice particulates, the gelatin scaffolds prepared with ice particulates facilitated formation of homogeneous cartilage tissue with significantly higher compressive modulus. The gelatin scaffolds with highly open pore structure and good mechanical property can be used to improve in vitro tissue-engineered cartilage.

  3. Hydrogel design for cartilage tissue engineering: A case study with hyaluronic acid

    PubMed Central

    Kim, Iris L.; Mauck, Robert L.; Burdick, Jason A.

    2011-01-01

    Hyaline cartilage serves as a low-friction and wear-resistant articulating surface in load-bearing, diarthrodial joints. Unfortunately, as the avascular, alymphatic nature of cartilage significantly impedes the body’s natural ability to regenerate, damage resulting from trauma and osteoarthritis necessitates repair attempts. Current clinical methods are generally limited in their ability to regenerate functional cartilage, and so research in recent years has focused on tissue engineering solutions in which the regeneration of cartilage is pursued through combinations of cells (e.g., chondrocytes or stem cells) paired with scaffolds (e.g., hydrogels, sponges, and meshes) in conjunction with stimulatory growth factors and bioreactors. A variety of synthetic and natural materials have been employed, most commonly in the form of hydrogels, and these systems have been tuned for optimal nutrient diffusion, connectivity of deposited matrix, degradation, soluble factor delivery, and mechanical loading for enhanced matrix production and organization. Even with these promising advances, the complex mechanical properties and biochemical composition of native cartilage have not been achieved, and engineering cartilage tissue still remains a significant challenge. Using hyaluronic acid hydrogels as an example, this review will follow the progress of material design specific to cartilage tissue engineering and propose possible future directions for the field. PMID:21903262

  4. Tissue Neogenesis and STRO-1 Expression in Immature and Mature Articular Cartilage

    PubMed Central

    Otsuki, Shuhei; Grogan, Shawn P.; Miyaki, Shigeru; Kinoshita, Mitsuo; Asahara, Hiroshi; Lotz, Martin K.

    2010-01-01

    This study determined the potential for neo tissue formation and the role of STRO-1+ cells in immature versus mature articular cartilage. Cartilage explants from immature and mature bovine knee joints were cultured for up to 12 weeks and stained with Safranin O, for type II collagen and STRO-1. Bovine chondrocyte pellet cultures and murine knee joints at the age of 2 weeks and 3 months and surgically injured cartilage were analyzed for changes in STRO-1 expression patterns. Results show that immature explants contained more STRO-1+ cells than mature explants. After 8 weeks in culture, immature explants showed STRO-1+ cell proliferation and newly formed tissue, which contained glycosaminoglycan and type II collagen. Mature cartilage explants showed only minimal cell expansion and neo tissue formation. Pellet cultures with chondrocytes from immature cartilage showed increased glycosaminoglycan synthesis and STRO-1+ staining as compared to pellets from mature chondrocytes. The frequency of STRO-1+ cells in murine knee joints significantly declined with joint maturation. Following surgical injury, immature explants had higher potential for tissue repair than mature explants. In conclusion, these findings suggest that the high percentage of STRO-1+ cells in immature cartilage changes with joint maturation. STRO-1+ cells have the potential to form new cartilage spontaneously and after tissue injury. PMID:19603515

  5. Microfracture for the treatment of cartilage defects in the knee joint - A golden standard?

    PubMed

    Erggelet, Christoph; Vavken, P

    2016-01-01

    The evidence for the effectiveness of the microfracture procedure is largely derived from case series and few randomized trials. Clinical outcomes improve with microfracture for the most part, but in some studies these effects are not sustained. The quality of cartilage repair following microfracture is variable and inconsistent due to unknown reasons. Younger patients have better clinical outcomes and quality of cartilage repair than older patients. When lesion location was shown to affect microfracture outcome, patients with lesions of the femoral condyle have the best clinical improvements and quality of cartilage repair compared with patients who had lesions in other areas. Patients with smaller lesions have better clinical improvement than patients with larger lesions. The necessity of long postoperative CPM and restricted weight bearing is widely accepted but not completely supported by solid data. Maybe new developments like the scaffold augmented microfracture(6) will show even more consistent clinical and biological results as well as faster rehabilitation for the treatment of small to medium sized cartilage defects in younger individuals. All in all there is limited evidence that micro fracture should be accepted as gold standard for the treatment of cartilage lesions in the knee joint. There is no study available which compares empty controls or non-surgical treatment/physiotherapy with microfracture. According to the literature there is even evidence for self regeneration of cartilage lesions. The natural history of damaged cartilage seems to be written e.g. by inflammatory processes, genetic predisposition and other factors. Possibly that explains the large variety of the clinical outcome after micro fracture and possibly the standard tools for evaluation of new technologies (randomized controlled trials, case series, etc.) are not sufficient (anymore). Future technologies will be evaluated by big data from international registries for earlier

  6. Microfracture for the treatment of cartilage defects in the knee joint - A golden standard?

    PubMed

    Erggelet, Christoph; Vavken, P

    2016-01-01

    The evidence for the effectiveness of the microfracture procedure is largely derived from case series and few randomized trials. Clinical outcomes improve with microfracture for the most part, but in some studies these effects are not sustained. The quality of cartilage repair following microfracture is variable and inconsistent due to unknown reasons. Younger patients have better clinical outcomes and quality of cartilage repair than older patients. When lesion location was shown to affect microfracture outcome, patients with lesions of the femoral condyle have the best clinical improvements and quality of cartilage repair compared with patients who had lesions in other areas. Patients with smaller lesions have better clinical improvement than patients with larger lesions. The necessity of long postoperative CPM and restricted weight bearing is widely accepted but not completely supported by solid data. Maybe new developments like the scaffold augmented microfracture(6) will show even more consistent clinical and biological results as well as faster rehabilitation for the treatment of small to medium sized cartilage defects in younger individuals. All in all there is limited evidence that micro fracture should be accepted as gold standard for the treatment of cartilage lesions in the knee joint. There is no study available which compares empty controls or non-surgical treatment/physiotherapy with microfracture. According to the literature there is even evidence for self regeneration of cartilage lesions. The natural history of damaged cartilage seems to be written e.g. by inflammatory processes, genetic predisposition and other factors. Possibly that explains the large variety of the clinical outcome after micro fracture and possibly the standard tools for evaluation of new technologies (randomized controlled trials, case series, etc.) are not sufficient (anymore). Future technologies will be evaluated by big data from international registries for earlier

  7. XRCC1 and base excision repair balance in response to nitric oxide.

    PubMed

    Mutamba, James T; Svilar, David; Prasongtanakij, Somsak; Wang, Xiao-Hong; Lin, Ying-Chih; Dedon, Peter C; Sobol, Robert W; Engelward, Bevin P

    2011-12-10

    Inflammation associated reactive oxygen and nitrogen species (RONs), including peroxynitrite (ONOO(-)) and nitric oxide (NO), create base lesions that potentially play a role in the toxicity and large genomic rearrangements associated with many malignancies. Little is known about the role of base excision repair (BER) in removing these endogenous DNA lesions. Here, we explore the role of X-ray repair cross-complementing group 1 (XRCC1) in attenuating RONs-induced genotoxicity. XRCC1 is a scaffold protein critical for BER for which polymorphisms modulate the risk of cancer. We exploited CHO and human glioblastoma cell lines engineered to express varied levels of BER proteins to study XRCC1. Cytotoxicity and the levels of DNA repair intermediates (single-strand breaks; SSB) were evaluated following exposure of the cells to the ONOO(-) donor, SIN-1, and to gaseous NO. XRCC1 null cells were slightly more sensitive to SIN-1 than wild-type cells. We used small-scale bioreactors to expose cells to NO and found that XRCC1-deficient CHO cells were not sensitive. However, using a molecular beacon assay to test lesion removal in vitro, we found that XRCC1 facilitates AAG-initiated excision of two key NO-induced DNA lesions: 1,N(6)-ethenoadenine and hypoxanthine. Furthermore, overexpression of AAG rendered XRCC1-deficient cells sensitive to NO-induced DNA damage. These results show that AAG is a key glycosylase for BER of NO-induced DNA damage and that XRCC1's role in modulating sensitivity to RONs is dependent upon the cellular level of AAG. This demonstrates the importance of considering the expression of other components of the BER pathway when evaluating the impact of XRCC1 polymorphisms on cancer risk.

  8. Survival and SOS response induction in ultraviolet B irradiated Escherichia coli cells with defective repair mechanisms.

    PubMed

    Prada Medina, Cesar Augusto; Aristizabal Tessmer, Elke Tatjana; Quintero Ruiz, Nathalia; Serment-Guerrero, Jorge; Fuentes, Jorge Luis

    2016-06-01

    Purpose In this paper, the contribution of different genes involved in DNA repair for both survival and SOS induction in Escherichia coli mutants exposed to ultraviolet B radiation (UVB, [wavelength range 280-315 nm]) was evaluated. Materials and methods E. coli strains defective in uvrA, oxyR, recO, recN, recJ, exoX, recB, recD or xonA genes were used to determine cell survival. All strains also had the genetic sulA::lacZ fusion, which allowed for the quantification of SOS induction through the SOS Chromotest. Results Five gene products were particularly important for survival, as follows: UvrA > RecB > RecO > RecJ > XonA. Strains defective in uvrA and recJ genes showed elevated SOS induction compared with the wild type, which remained stable for up to 240 min after UVB-irradiation. In addition, E. coli strains carrying the recO or recN mutation showed no SOS induction. Conclusions The nucleotide excision and DNA recombination pathways were equally used to repair UVB-induced DNA damage in E. coli cells. The sulA gene was not turned off in strains defective in UvrA and RecJ. RecO protein was essential for processing DNA damage prior to SOS induction. In this study, the roles of DNA repair proteins and their contributions to the mechanisms that induce SOS genes in E. coli are proposed. PMID:26967458

  9. Survival and SOS response induction in ultraviolet B irradiated Escherichia coli cells with defective repair mechanisms.

    PubMed

    Prada Medina, Cesar Augusto; Aristizabal Tessmer, Elke Tatjana; Quintero Ruiz, Nathalia; Serment-Guerrero, Jorge; Fuentes, Jorge Luis

    2016-06-01

    Purpose In this paper, the contribution of different genes involved in DNA repair for both survival and SOS induction in Escherichia coli mutants exposed to ultraviolet B radiation (UVB, [wavelength range 280-315 nm]) was evaluated. Materials and methods E. coli strains defective in uvrA, oxyR, recO, recN, recJ, exoX, recB, recD or xonA genes were used to determine cell survival. All strains also had the genetic sulA::lacZ fusion, which allowed for the quantification of SOS induction through the SOS Chromotest. Results Five gene products were particularly important for survival, as follows: UvrA > RecB > RecO > RecJ > XonA. Strains defective in uvrA and recJ genes showed elevated SOS induction compared with the wild type, which remained stable for up to 240 min after UVB-irradiation. In addition, E. coli strains carrying the recO or recN mutation showed no SOS induction. Conclusions The nucleotide excision and DNA recombination pathways were equally used to repair UVB-induced DNA damage in E. coli cells. The sulA gene was not turned off in strains defective in UvrA and RecJ. RecO protein was essential for processing DNA damage prior to SOS induction. In this study, the roles of DNA repair proteins and their contributions to the mechanisms that induce SOS genes in E. coli are proposed.

  10. Mesenchymal stem cells as a potential pool for cartilage tissue engineering.

    PubMed

    Csaki, C; Schneider, P R A; Shakibaei, M

    2008-11-20

    Osteoarthritis (OA) resulting from trauma, degenerative or age-related disease presents a major clinical challenge due to the limited repair capacity of articular cartilage. This poor self-repair capacity of osteochondral defects has resulted in the development of a wide variety of new treatment approaches. Although the use of chondrocytes in applications of cartilage tissue engineering is still prevalent, concerns associated with donor-site morbidity, cell de-differentiation and the limited lifespan of these cells have brought the use of mesenchymal stem cells (MSCs) to the forefront of such applications. Therefore, in the last two decades MSCs have come into the focus of connective tissue engineering and regenerative medicine and have become increasingly sought after as an alternative cell source for improving well-established methods of osteochondrotic cartilage defect repair such as the Autologous Chondrocyte Transplantation method, but are also being tested as an ideal cell source in combination with newly developed implantable scaffolds or as a target/carrier cell in other new concepts of regenerative medicine. However, up to now, although in animal models MSCs have already shown significant potential for cartilage repair and novel approaches using MSCs as an alternative cell source to patient-derived chondrocytes are being tested, much more research is needed before feasible clinical application of MSCs becomes reality.

  11. 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

  12. Induced superficial chondrocyte death reduces catabolic cartilage damage in murine posttraumatic osteoarthritis.

    PubMed

    Zhang, Minjie; Mani, Sriniwasan B; He, Yao; Hall, Amber M; Xu, Lin; Li, Yefu; Zurakowski, David; Jay, Gregory D; Warman, Matthew L

    2016-08-01

    Joints that have degenerated as a result of aging or injury contain dead chondrocytes and damaged cartilage. Some studies have suggested that chondrocyte death precedes cartilage damage, but how the loss of chondrocytes affects cartilage integrity is not clear. In this study, we examined whether chondrocyte death undermines cartilage integrity in aging and injury using a rapid 3D confocal cartilage imaging technique coupled with standard histology. We induced autonomous expression of diphtheria toxin to kill articular surface chondrocytes in mice and determined that chondrocyte death did not lead to cartilage damage. Moreover, cartilage damage after surgical destabilization of the medial meniscus of the knee was increased in mice with intact chondrocytes compared with animals whose chondrocytes had been killed, suggesting that chondrocyte death does not drive cartilage damage in response to injury. These data imply that chondrocyte catabolism, not death, contributes to articular cartilage damage following injury. Therefore, therapies targeted at reducing the catabolic phenotype may protect against degenerative joint disease. PMID:27427985

  13. Targeting Transporters: Promoting Blood-Brain Barrier Repair in Response to Oxidative Stress Injury

    PubMed Central

    Ronaldson, Patrick T.; Davis, Thomas P.

    2015-01-01

    The blood-brain barrier (BBB) is a physical and biochemical barrier that precisely regulates the ability of endogenous and exogenous substances to accumulate within brain tissue. It possesses structural and biochemical features (i.e., tight junction and adherens junction protein complexes, influx and efflux transporters) that work in concert to control solute permeation. Oxidative stress, a critical component of several diseases including cerebral hypoxia/ischemia and peripheral inflammatory pain, can cause considerable injury to the BBB and lead to significant CNS pathology. This suggests a critical need for novel therapeutic approaches that can protect the BBB in diseases with an oxidative stress component. Recent studies have identified molecular targets (i.e., endogenous transporters, intracellular signaling systems) that can be exploited for optimization of endothelial drug delivery or for control of transport of endogenous substrates such as the antioxidant glutathione (GSH). In particular, targeting transporters offers a unique approach to protect BBB integrity by promoting repair of cell-cell interactions at the level of the brain microvascular endothelium. This review summarizes current knowledge in this area and emphasizes those targets that present considerable opportunity for providing BBB protection and/or promoting BBB repair in the setting of oxidative stress. PMID:25796436

  14. Scaffolds for Controlled Release of Cartilage Growth Factors.

    PubMed

    Morille, Marie; Venier-Julienne, Marie-Claire; Montero-Menei, Claudia N

    2015-01-01

    In recent years, cell-based therapies using adult stem cells have attracted considerable interest in regenerative medicine. A tissue-engineered construct for cartilage repair should provide a support for the cell and allow sustained in situ delivery of bioactive factors capable of inducing cell differentiation into chondrocytes. Pharmacologically active microcarriers (PAMs), made of biodegradable and biocompatible poly (D,L-lactide-co-glycolide acid) (PLGA), are a unique system which combines these properties in an adaptable and simple microdevice. This device relies on nanoprecipitation of proteins encapsulated in polymeric microspheres with a solid in oil in water emulsion-solvent evaporation process, and their subsequent coating with extracellular matrix protein molecules. Here, we describe their preparation process, and some of their characterization methods for an application in cartilage tissue engineering. PMID:26445838

  15. Biomaterials and scaffold design: key to tissue-engineering cartilage.

    PubMed

    Raghunath, Joanne; Rollo, John; Sales, Kevin M; Butler, Peter E; Seifalian, Alexander M

    2007-02-01

    Cartilage remains one of the most challenging tissues to reconstruct or replace, owing to its complex geometry in facial structures and mechanical strength at articular surfaces in joints. This non-vascular tissue has poor replicative capacity and damage results in its functionally inferior repair tissue, fibrocartilage. This has led to a drive for advancements in tissue engineering. The variety of polymers and fabrication techniques available continues to expand. Pore size, porosity, biocompatibility, shape specificity, integration with native tissue, degradation tailored to rate of neocartilage formation and cost efficiency are important factors which need consideration in the development of a scaffold. The present review considers the current polymers and fabrication methodologies used in scaffold engineering for cartilage and postulates whether we are closer to developing the ideal scaffold for clinical application.

  16. Use of butyl-2-cyanoacrylate in rabbit auricular cartilage.

    PubMed

    Fung, R Q; Ronis, M L; Mohr, R M

    1985-07-01

    Since the nonsuture repair of blood vessels with methyl-2-cyanoacrylate was described in 1960, the advantages of a tissue adhesive over conventional sutures became evident. A survey of 115 otolaryngology programs showed that cyanoacrylates, mainly butyl-2-cyanoacrylate (B2C), are used more extensively than indicated in the literature. Cartilage grafts are commonly used in facial plastic procedures. In a study comparing B2C with conventional suture techniques in securing rabbit auricular cartilage autografts, sutures were used in the left control ear and B2C was used in the right experimental ear. Rabbits sacrificed at two weeks to 12 months showed graft viability in all samples and no statistically significant histologic difference between the grafts secured by either method.

  17. Adipose-derived stem cells in cartilage regeneration: current perspectives.

    PubMed

    Bielli, Alessandra; Scioli, Maria Giovanna; Gentile, Pietro; Cervelli, Valerio; Orlandi, Augusto

    2016-10-01

    Repair of cartilage injuries represents a musculoskeletal medicine criticism because of the poor ability to self-renewal of adult cartilage. Therefore, research focuses on developing new regenerative strategies combining chondrocytes or stem cells, scaffolds and growth factors. Because of the low proliferation capability of explanted chondrocytes, new chondrogenesis models, employing human adipose-derived stem cells (ASCs), have been investigated. ASCs are readily accessible with no morbidity and display the capability to differentiate into several cell lineages, including the spontaneous chondrogenic differentiation when entrapped in collagen gel scaffolds. Recent studies also defined some biomolecular mechanisms involved in ASC chondrogenesis in vitro, and their regenerative properties in bioengineered scaffolds and in the presence of growth factors. However, further investigations are required to validate these exciting preclinical results for the application of bioenginereed ASCs in the clinical practice. PMID:27599358

  18. Homologous recombination repair signaling in chemical carcinogenesis: prolonged particulate hexavalent chromium exposure suppresses the Rad51 response in human lung cells.

    PubMed

    Qin, Qin; Xie, Hong; Wise, Sandra S; Browning, Cynthia L; Thompson, Kelsey N; Holmes, Amie L; Wise, John Pierce

    2014-11-01

    The aim of this study was to focus on hexavalent chromium, [Cr(VI)], a chemical carcinogen and major public health concern, and consider its ability to impact DNA double strand break repair. We further focused on particulate Cr(VI), because it is the more potent carcinogenic form of Cr(VI). DNA double strand break repair serves to protect cells against the detrimental effects of DNA double strand breaks. For particulate Cr(VI), data show DNA double strand break repair must be overcome for neoplastic transformation to occur. Acute Cr(VI) exposures reveal a robust DNA double strand break repair response, however, longer exposures have not been considered. Using the comet assay, we found longer exposures to particulate zinc chromate induced concentration-dependent increases in DNA double strand breaks indicating breaks were occurring throughout the exposure time. Acute (24 h) exposure induced DNA double strand break repair signaling by inducing Mre11 foci formation, ATM phosphorylation and phosphorylated ATM foci formation, Rad51 protein levels and Rad51 foci formation. However, longer exposures reduced the Rad51 response. These data indicate a major chemical carcinogen can simultaneously induce DNA double strand breaks and alter their repair and describe a new and important aspect of the carcinogenic mechanism for Cr(VI). PMID:25173789

  19. Boundary mode lubrication of articular cartilage by recombinant human lubricin.

    PubMed

    Gleghorn, Jason P; Jones, Aled R C; Flannery, Carl R; Bonassar, Lawrence J

    2009-06-01

    Lubrication of cartilage involves a variety of physical and chemical factors, including lubricin, a synovial glycoprotein that has been shown to be a boundary lubricant. It is unclear how lubricin boundary lubricates a wide range of bearings from tissue to artificial surfaces, and if the mechanism is the same for both soluble and bound lubricin. In the current study, experiments were conducted to investigate the hypothesis that recombinant human lubricin (rh-lubricin) lubricates cartilage in a dose-dependent manner and that soluble and bound fractions of rh-lubricin both contribute to the lubrication process. An rh-lubricin dose response was observed with maximal lubrication achieved at concentrations of rh-lubricin greater than 50 microg/mL. A concentration-response variable-slope model was fit to the data, and indicated that rh-lubricin binding to cartilage was not first order. The pattern of decrease in equilibrium friction coefficient indicated that aggregation of rh-lubricin or steric arrangement may regulate boundary lubrication. rh-lubricin localized at the cartilage surface was found to lubricate a cartilage-glass interface in boundary mode, as did soluble rh-lubricin at high concentrations (150 microg/mL); however, the most effective lubrication occurred when both soluble and bound rh-lubricin were present at the interface. These findings point to two distinct mechanisms by which rh-lubricin lubricates, one mechanism involving lubricin bound to the tissue surface and the other involving lubricin in solution.

  20. Effects of osmotic challenges on membrane potential in human articular chondrocytes from healthy and osteoarthritic cartilage.

    PubMed

    Sánchez, Julio C; López-Zapata, Diego F

    2010-01-01

    Changes in external osmolarity arise from variations in mechanical loads on joints and may affect the homeostasis of chondrocytes, which are the only cell type responsible for matrix turnover. Accordingly, variations in membrane potential may affect cartilage production. The present study assessed the effects of variations in external osmolarity on membrane potential and the possible mechanisms responsible for this response. Membrane potential was measured by the patch clamp whole-cell technique using human articular chondrocytes freshly isolated from healthy and osteoarthritic cartilage. The membrane potential was -39±4 mV in articular human chondrocytes from healthy cartilage and -26±4 mV in those from osteoarthritic cartilage. Increasing the osmolarity produced a reversible hyperpolarization mediated by K+ efflux through BKCa channels in both groups of chondrocytes, but the response in osteoarthritic cells was significantly reduced; no other K+ pathways were involved in this effect. Alternatively, decreasing the osmolarity elicited depolarization in healthy chondrocytes but did not produce any response in chondrocytes from osteoarthritic cartilage. The depolarization was dependent on Na+ influx through Gd3+-sensitive stretch-activated cation channels and was independent of external Ca2+. The differential responses observed in chondrocytes from osteoarthritic cartilage suggest that disregulation on the responses to external osmolarity may be involved in the process that leads to the alterations in the cartilage structure observed in osteoarthritis.

  1. Cartilage Derived from Bone Marrow Mesenchymal Stem Cells Expresses Lubricin In Vitro and In Vivo

    PubMed Central

    Nakagawa, Yusuke; Muneta, Takeshi; Otabe, Koji; Ozeki, Nobutake; Mizuno, Mitsuru; Udo, Mio; Saito, Ryusuke; Yanagisawa, Katsuaki; Ichinose, Shizuko; Koga, Hideyuki; Tsuji, Kunikazu; Sekiya, Ichiro

    2016-01-01

    Objective Lubricin expression in the superficial cartilage will be a crucial factor in the success of cartilage regeneration. Mesenchymal stem cells (MSCs) are an attractive cell source and the use of aggregates of MSCs has some advantages in terms of chondrogenic potential and efficiency of cell adhesion. Lubricin expression in transplanted MSCs has not been fully elucidated so far. Our goals were to determine (1) whether cartilage pellets of human MSCs expressed lubricin in vitro chondrogenesis, (2) whether aggregates of human MSCs promoted lubricin expression, and (3) whether aggregates of MSCs expressed lubricin in the superficial cartilage after transplantation into osteochondral defects in rats. Methods For in vitro analysis, human bone marrow (BM) MSCs were differentiated into cartilage by pellet culture, and also aggregated using the hanging drop technique. For an animal study, aggregates of BM MSCs derived from GFP transgenic rats were transplanted to the osteochondral defect in the trochlear groove of wild type rat knee joints. Lubricin expression was mainly evaluated in differentiated and regenerated cartilages. Results In in vitro analysis, lubricin was detected in the superficial zone of the pellets and conditioned medium. mRNA expression of Proteoglycan4 (Prg4), which encodes lubricin, in pellets was significantly higher than that of undifferentiated MSCs. Aggregates showed different morphological features between the superficial and deep zone, and the Prg4 mRNA expression increased after aggregate formation. Lubricin was also found in the aggregate. In a rat study, articular cartilage regeneration was significantly better in the MSC group than in the control group as shown by macroscopical and histological analysis. The transmission electron microscope showed that morphology of the superficial cartilage in the MSC group was closer to that of the intact cartilage than in the control group. GFP positive cells remained in the repaired tissue and

  2. Learn, simplify and implement: developmental re-engineering strategies for cartilage repai.

    PubMed

    Occhetta, Paola; Stüdle, Chiara; Barbero, Andrea; Martin, Ivan

    2016-01-01

    The limited self-healing capacity of cartilage in adult individuals, and its tendency to deteriorate once structurally damaged, makes the search for therapeutic strategies following cartilage-related traumas relevant and urgent. To date, autologous cell-based therapies represent the most advanced treatments, but their clinical success is still hampered by the long-term tendency to form fibrous as opposed to hyaline cartilage tissue. Would the efficiency and robustness of therapies be enhanced if cartilage regeneration approaches were based on the attempt to recapitulate processes occurring during cartilage development ("developmental engineering")? And from this perspective, shouldn't cartilage repair strategies be inspired by development, but adapted to be effective in a context (an injured joint in an adult individual) that is different from the embryo ("developmental re-engineering")? Here, starting from mesenchymal stem/stromal cells (MSCs) as an adult cell source possibly resembling features of the embryonic mesenchyme, we propose a developmental re-engineering roadmap based on the following three steps: (i) learn from embryonic cartilage development which are the key pathways involved in MSC differentiation towards stable cartilage, (ii) simplify the complex developmental events by approximation to essential molecular pathways, possibly by using in vitro high-throughput models and, finally, (iii) implement the outcomes at the site of the injury by establishing an appropriate interface between the delivered signals and the recipient environment (e.g., by controlling inflammation and angiogenesis). The proposed re-design of developmental machinery by establishing artificial developmental events may offer a chance for regeneration to those tissues, like cartilage, with limited capacity to recover from injuries. PMID:27544431

  3. Crosslinkable Hydrogels Derived from Cartilage, Meniscus, and Tendon Tissue

    PubMed Central

    Visser, Jetze; Levett, Peter A.; te Moller, Nikae C.R.; Besems, Jeremy; Boere, Kristel W.M.; van Rijen, Mattie H.P.; de Grauw, Janny C.; Dhert, Wouter J.A.; van Weeren, P. René

    2015-01-01

    Decellularized tissues have proven to be versatile matrices for the engineering of tissues and organs. These matrices usually consist of collagens, matrix-specific proteins, and a set of largely undefined growth factors and signaling molecules. Although several decellularized tissues have found their way to clinical applications, their use in the engineering of cartilage tissue has only been explored to a limited extent. We set out to generate hydrogels from several tissue-derived matrices, as hydrogels are the current preferred cell carriers for cartilage repair. Equine cartilage, meniscus, and tendon tissue was harvested, decellularized, enzymatically digested, and functionalized with methacrylamide groups. After photo-cross-linking, these tissue digests were mechanically characterized. Next, gelatin methacrylamide (GelMA) hydrogel was functionalized with these methacrylated tissue digests. Equine chondrocytes and mesenchymal stromal cells (MSCs) (both from three donors) were encapsulated and cultured in vitro up to 6 weeks. Gene expression (COL1A1, COL2A1, ACAN, MMP-3, MMP-13, and MMP-14), cartilage-specific matrix formation, and hydrogel stiffness were analyzed after culture. The cartilage, meniscus, and tendon digests were successfully photo-cross-linked into hydrogels. The addition of the tissue-derived matrices to GelMA affected chondrogenic differentiation of MSCs, although no consequent improvement was demonstrated. For chondrocytes, the tissue-derived matrix gels performed worse compared to GelMA alone. This work demonstrates for the first time that native tissues can be processed into crosslinkable hydrogels for the engineering of tissues. Moreover, the differentiation of encapsulated cells can be influenced in these stable, decellularized matrix hydrogels. PMID:25557049

  4. Crosslinkable hydrogels derived from cartilage, meniscus, and tendon tissue.

    PubMed

    Visser, Jetze; Levett, Peter A; te Moller, Nikae C R; Besems, Jeremy; Boere, Kristel W M; van Rijen, Mattie H P; de Grauw, Janny C; Dhert, Wouter J A; van Weeren, P René; Malda, Jos

    2015-04-01

    Decellularized tissues have proven to be versatile matrices for the engineering of tissues and organs. These matrices usually consist of collagens, matrix-specific proteins, and a set of largely undefined growth factors and signaling molecules. Although several decellularized tissues have found their way to clinical applications, their use in the engineering of cartilage tissue has only been explored to a limited extent. We set out to generate hydrogels from several tissue-derived matrices, as hydrogels are the current preferred cell carriers for cartilage repair. Equine cartilage, meniscus, and tendon tissue was harvested, decellularized, enzymatically digested, and functionalized with methacrylamide groups. After photo-cross-linking, these tissue digests were mechanically characterized. Next, gelatin methacrylamide (GelMA) hydrogel was functionalized with these methacrylated tissue digests. Equine chondrocytes and mesenchymal stromal cells (MSCs) (both from three donors) were encapsulated and cultured in vitro up to 6 weeks. Gene expression (COL1A1, COL2A1, ACAN, MMP-3, MMP-13, and MMP-14), cartilage-specific matrix formation, and hydrogel stiffness were analyzed after culture. The cartilage, meniscus, and tendon digests were successfully photo-cross-linked into hydrogels. The addition of the tissue-derived matrices to GelMA affected chondrogenic differentiation of MSCs, although no consequent improvement was demonstrated. For chondrocytes, the tissue-derived matrix gels performed worse compared to GelMA alone. This work demonstrates for the first time that native tissues can be processed into crosslinkable hydrogels for the engineering of tissues. Moreover, the differentiation of encapsulated cells can be influenced in these stable, decellularized matrix hydrogels.

  5. Expression of genes responsible for the repair of mispaired bases of the DNA (MLH1) in invasive ductal breast carcinoma.

    PubMed

    Milanović, Rudolf; Stanec, Sanda; Stanec, Mladen; Korusić, Andelko; Husedzinović, Ino; Razumović, Jasminka Jakić

    2013-09-01

    Breast cancer is a heterogeneous group of diseases determined and distinguished by cellular type, gene expression and clinical signs and symptoms. Identification of histological and biological markers is of great value in predicting the progression of tumor growth and anticipating the expected response to various treatment options. Due to a high degree of cell proliferation in breast tumors and high genetic instability of these tumors, as a consequence of defective DNA repair mechanisms, chemotherapy as a treatment option often renders very successful results. During our scientific research we wanted to determine the involvement of the genetic polymorphisms of DNA mismatch repair system (MLH1 gene) and the subsequent development of breast carcinoma. This study included 108 patients who were surgically treated for invasive breast cancer at the Department of Plastic, Reconstructive and Aesthetic Surgery, University Hospital "Dubrava". The expression of the MLH1 gene was determined by immunohistochemical methods. The results showed that 82.9% of tumor cells expressed the MLH1 gene. Analysis of survival rate for patients with invasive ductal breast cancer showed a statistically significant (p = 0.043) correlation with the expression of MLH1 genes. The overall five year survival rate of our patients was 78.7%. These results indicate that there is a possible involvement of MLH1 gene in the progression and development of breast cancer.

  6. A study of the sympathetic skin response and sensory nerve action potential after median and ulnar nerve repair.

    PubMed

    Jazayeri, M; Ghavanini, M R; Rahimi, H R; Raissi, G R

    2003-01-01

    The purpose of this study was to compare SSR with sensory nerve action potential (SNAP) responses in regeneration of injured peripheral nerves after nerve repair. We studied 10 male patients with a mean age of 26.7 years. All the patients had complete laceration of median or ulnar nerves. The patients were followed up at least for six months. SSR and SNAP assessment were performed every one to two months. Normal hands were used as controls. SSR was positive after 15.8 +/- 9.4 weeks (mean +/- 2 SD) and SNAP after 27.8 +/- 12.9 weeks (mean +/- 2 SD). The difference was statistically significant (P value < 0.001). This can be due to more rapid growth of sympathetic unmyelinated fibers relative to sensory myelinated fibers. This study also shows that recovery of the sudomotor activity following nerve repair is satisfactory in general and SSR can be used as a useful and sensitive method in the evaluation of sudomotor nerve regeneration.

  7. Diminished Schwann cell repair responses underlie age-associated impaired axonal regeneration.

    PubMed

    Painter, Michio W; Brosius Lutz, Amanda; Cheng, Yung-Chih; Latremoliere, Alban; Duong, Kelly; Miller, Christine M; Posada, Sean; Cobos, Enrique J; Zhang, Alice X; Wagers, Amy J; Havton, Leif A; Barres, Ben; Omura, Takao; Woolf, Clifford J

    2014-07-16

    The regenerative capacity of the peripheral nervous system declines with age. Why this occurs, however, is unknown. We demonstrate that 24-month-old mice exhibit an impairment of functional recovery after nerve injury compared to 2-month-old animals. We find no difference in the intrinsic growth capacity between aged and young sensory neurons in vitro or in their ability to activate growth-associated transcriptional programs after injury. Instead, using age-mismatched nerve transplants in vivo, we show that the extent of functional recovery depends on the age of the nerve graft, and not the age of the host. Molecular interrogation of the sciatic nerve reveals that aged Schwann cells (SCs) fail to rapidly activate a transcriptional repair program after injury. Functionally, aged SCs exhibit impaired dedifferentiation, myelin clearance, and macrophage recruitment. These results suggest that the age-associated decline in axonal regeneration results from diminished Schwann cell plasticity, leading to slower myelin clearance.

  8. Using Iterative Repair to Increase the Responsiveness of Planning and Scheduling for Autonomous Spacecraft

    NASA Technical Reports Server (NTRS)

    Chien, Steve; Knight, Russell; Stechert, Andre; Sherwood, Rob; Rabideau, Gregg

    1998-01-01

    An autonomous spacecraft must balance long-term and short-term considerations. It must perform purposeful activities that ensure long-term science and engineering goals are achieved and ensure that it maintains positive resource margins. This requires planning in advance to avoid a series of shortsighted decisions that can lead to failure, However, it must also respond in a timely fashion to a somewhat dynamic and unpredictable environment. Thus, spacecraft plans must often be modified due to fortuitous events such as early completion of observations and setbacks such as failure to acquire a guidestar for a science observation. This paper describes the use of iterative repair to support continuous modification and updating of a current working plan in light of changing operating context.

  9. Mechanisms of disruption of the articular cartilage surface in inflammation. Neutrophil elastase increases availability of collagen type II epitopes for binding with antibody on the surface of articular cartilage.

    PubMed Central

    Jasin, H E; Taurog, J D

    1991-01-01

    We recently observed that specific antibodies to type II collagen do not bind in appreciable amounts to the intact surface of articular cartilage, whereas antibodies to the minor collagen types V, VI, and IX do. These results suggest that the outermost cartilage surface layer prevented interaction of the antibodies with the major collagen type in articular cartilage. The present studies were designed to investigate the pathogenic mechanisms involved in the disruption of the cartilage surface layer in inflammatory arthritis. Articular cartilage obtained from rabbits undergoing acute antigen-induced arthritis of 72 h duration showed a significant increase in binding of anti-type II antibody to cartilage surfaces compared with normal control cartilage (P less than 0.01). Augmentation of anti-type II binding was also observed upon in vitro incubation of bovine articular slices or intact rabbit patellar cartilage for 1 h with human polymorphonuclear neutrophils (PMN), PMN lysates, or purified human PMN elastase. This increase was not inhibited by sodium azide, nor was it enhanced by incubation of cartilage with the strong oxidant hypochlorous acid. Chondrocyte-mediated matrix proteoglycan degradation in cartilage explants cultured in the presence of cytokines failed to increase antibody binding appreciably. The augmentation in antibody binding seen with PMN lysates was inhibited by the nonspecific serine-esterase inhibitor PMSF, but not by the divalent metal chelator EDTA. The elastase-specific inhibitor AAPVCMK also inhibited most of the PMN-induced increase in antibody binding, whereas the cathepsin G-specific inhibitor GLPCMK was much less effective. Incubation of intact cartilage with purified human PMN elastase indicated that this serine esterase could account for the increase in anti-type II collagen antibody binding to intact cartilage surfaces. These studies suggest that in an inflammatory response, PMN-derived elastase degrades the outer layer of articular

  10. Concise review: role of mesenchymal stem cells in wound repair.

    PubMed

    Maxson, Scott; Lopez, Erasmo A; Yoo, Dana; Danilkovitch-Miagkova, Alla; Leroux, Michelle A

    2012-02-01

    Wound healing requires a coordinated interplay among cells, growth factors, and extracellular matrix proteins. Central to this process is the endogenous mesenchymal stem cell (MSC), which coordinates the repair response by recruiting other host cells and secreting growth factors and matrix proteins. MSCs are self-renewing multipotent stem cells that can differentiate into various lineages of mesenchymal origin such as bone, cartilage, tendon, and fat. In addition to multilineage differentiation capacity, MSCs regulate immune response and inflammation and possess powerful tissue protective and reparative mechanisms, making these cells attractive for treatment of different diseases. The beneficial effect of exogenous MSCs on wound healing was observed in a variety of animal models and in reported clinical cases. Specifically, they have been successfully used to treat chronic wounds and stimulate stalled healing processes. Recent studies revealed that human placental membranes are a rich source of MSCs for tissue regeneration and repair. This review provides a concise summary of current knowledge of biological properties of MSCs and describes the use of MSCs for wound healing. In particular, the scope of this review focuses on the role MSCs have in each phase of the wound-healing process. In addition, characterization of MSCs containing skin substitutes is described, demonstrating the presence of key growth factors and cytokines uniquely suited to aid in wound repair.

  11. Devitalisation of human cartilage by high hydrostatic pressure treatment: Subsequent cultivation of chondrocytes and mesenchymal stem cells on the devitalised tissue

    PubMed Central

    Hiemer, B.; Genz, B.; Jonitz-Heincke, A.; Pasold, J.; Wree, A.; Dommerich, S.; Bader, R.

    2016-01-01

    The regeneration of cartilage lesions still represents a major challenge. Cartilage has a tissue-specific architecture, complicating recreation by synthetic biomaterials. A novel approach for reconstruction is the use of devitalised cartilage. Treatment with high hydrostatic pressure (HHP) achieves devitalisation while biomechanical properties are remained. Therefore, in the present study, cartilage was devitalised using HHP treatment and the potential for revitalisation with chondrocytes and mesenchymal stem cells (MSCs) was investigated. The devitalisation of cartilage was performed by application of 480 MPa over 10 minutes. Effective cellular inactivation was demonstrated by the trypan blue exclusion test and DNA quantification. Histology and electron microscopy examinations showed undamaged cartilage structure after HHP treatment. For revitalisation chondrocytes and MSCs were cultured on devitalised cartilage without supplementation of chondrogenic growth factors. Both chondrocytes and MSCs significantly increased expression of cartilage-specific genes. ECM stainings showed neocartilage-like structure with positive AZAN staining as well as collagen type II and aggrecan deposition after three weeks of cultivation. Our results showed that HHP treatment caused devitalisation of cartilage tissue. ECM proteins were not influenced, thus, providing a scaffold for chondrogenic differentiation of MSCs and chondrocytes. Therefore, using HHP-treated tissue might be a promising approach for cartilage repair. PMID:27671122

  12. The properties of bioengineered chondrocyte sheets for cartilage regeneration

    PubMed Central

    Mitani, Genya; Sato, Masato; Lee, Jeong IK; Kaneshiro, Nagatoshi; Ishihara, Miya; Ota, Naoshi; Kokubo, Mami; Sakai, Hideaki; Kikuchi, Tetsutaro; Mochida, Joji

    2009-01-01

    Background Although the clinical results of autologous chondrocyte implantation for articular cartilage defects have recently improved as a result of advanced techniques based on tissue engineering procedures, problems with cell handling and scaffold imperfections remain to be solved. A new cell-sheet technique has been developed, and is potentially able to overcome these obstacles. Chondrocyte sheets applicable to cartilage regeneration can be prepared with this cell-sheet technique using temperature-responsive culture dishes. However, for clinical application, it is necessary to evaluate the characteristics of the cells in these sheets and to identify their similarities to naive cartilage. Results The expression of SOX 9, collagen type 2, 27, integrin α10, and fibronectin genes in triple-layered chondrocyte sheets was significantly increased in comparison to those in conventional monolayer culture and in a single chondrocyte sheet, implying a nature similar to ordinary cartilage. In addition, immunohistochemistry demonstrated that collagen type II, fibronectin, and integrin α10 were present in the triple-layered chondrocyte sheets. Conclusion The results of this study indicate that these chondrocyte sheets with a consistent cartilaginous phenotype and adhesive properties may lead to a new strategy for cartilage regeneration. PMID:19267909

  13. Targeting TGFβ Signaling in Subchondral Bone and Articular Cartilage Homeostasis

    PubMed Central

    Zhen, Gehau; Cao, Xu

    2014-01-01

    Osteoarthritis (OA) is the most common degenerative joint disease, and there is no disease-modifying therapy for OA currently available. Targeting of articular cartilage alone may not be sufficient to halt this disease progression. Articular cartilage and subchondral bone act as a functional unit. Increasing evidence indicates that transforming growth factor β (TGFβ) plays a crucial role in maintaining homeostasis of both articular cartilage and subchondral bone. Activation of extracellular matrix latent TGFβ at the appropriate time and location is the prerequisite for its function. Aberrant activation of TGFβ in the subchondral bone in response to abnormal mechanical loading environment induces formation of osteroid islets at onset of osteoarthritis. As a result, alteration of subchondral bone structure changes the stress distribution on the articular cartilage and leads to its degeneration. Thus, inhibition of TGFβ activity in the subchondral bone may provide a new avenue of treatment for OA. In this review, we will respectively discuss the role of TGFβ in homeostasis of articular cartilage and subchondral bone as a novel target for OA therapy. PMID:24745631

  14. Regulated expression of the Saccharomyces cerevisiae DNA repair gene RAD7 in response to DNA damage and during sporulation.

    PubMed

    Jones, J S; Prakash, L; Prakash, S

    1990-06-11

    The RAD7 gene of Saccharomyces cerevisiae affects the proficiency of excision repair of DNA damaged by UV light. Here, we report our studies on the regulation of the RAD7 gene in response to UV irradiation and during sporulation. RAD7 transcript levels increased 6-fold within 40 min of exposure of cells to 37 J/m2 of UV light. Higher UV doses also elicited rapid increases in the level of RAD7 mRNA. RAD7 mRNA levels increased in sporulating MATa/MAT alpha diploid cells, but not in the asporogenous MATa/MATa strain exposed to sporulation conditions. The increase in RAD7 mRNA level in MATa/MAT alpha cells was 15-fold after 6 h and 9-fold after 7 h in sporulation medium; thereafter, RAD7 mRNA levels declined. Periodic transcription of RAD7 during sporulation suggests a role for RAD7 in this process.

  15. Optimality in DNA repair.

    PubMed

    Richard, Morgiane; Fryett, Matthew; Miller, Samantha; Booth, Ian; Grebogi, Celso; Moura, Alessandro

    2012-01-01

    DNA within cells is subject to damage from various sources. Organisms have evolved a number of mechanisms to repair DNA damage. The activity of repair enzymes carries its own risk, however, because the repair of two nearby lesions may lead to the breakup of DNA and result in cell death. We propose a mathematical theory of the damage and repair process in the important scenario where lesions are caused in bursts. We use this model to show that there is an optimum level of repair enzymes within cells which optimises the cell's response to damage. This optimal level is explained as the best trade-off between fast repair and a low probability of causing double-stranded breaks. We derive our results analytically and test them using stochastic simulations, and compare our predictions with current biological knowledge. PMID:21945337

  16. Major biological obstacles for persistent cell-based regeneration of articular cartilage

    PubMed Central

    Steinert, Andre F; Ghivizzani, Steven C; Rethwilm, Axel; Tuan, Rocky S; Evans, Christopher H; Nöth, Ulrich

    2007-01-01

    Hyaline articular cartilage, the load-bearing tissue of the joint, has very limited repair and regeneration capacities. The lack of efficient treatment modalities for large chondral defects has motivated attempts to engineer cartilage constructs in vitro by combining cells, scaffold materials and environmental factors, including growth factors, signaling molecules, and physical influences. Despite promising experimental approaches, however, none of the current cartilage repair strategies has generated long lasting hyaline cartilage replacement tissue that meets the functional demands placed upon this tissue in vivo. The reasons for this are diverse and can ultimately result in matrix degradation, differentiation or integration insufficiencies, or loss of the transplanted cells and tissues. This article aims to systematically review the different causes that lead to these impairments, including the lack of appropriate differentiation factors, hypertrophy, senescence, apoptosis, necrosis, inflammation, and mechanical stress. The current conceptual basis of the major biological obstacles for persistent cell-based regeneration of articular cartilage is discussed, as well as future trends to overcome these limitations. PMID:17561986

  17. A Synthetic Thermosensitive Hydrogel for Cartilage Bioprinting and Its Biofunctionalization with Polysaccharides.

    PubMed

    Abbadessa, Anna; Mouser, Vivian H M; Blokzijl, Maarten M; Gawlitta, Debby; Dhert, Wouter J A; Hennink, Wim E; Malda, Jos; Vermonden, Tina

    2016-06-13

    Hydrogels based on triblock copolymers of polyethylene glycol and partially methacrylated poly[N-(2-hydroxypropyl) methacrylamide mono/dilactate] make up an attractive class of biomaterials because of their biodegradability, cytocompatibility, and tunable thermoresponsive and mechanical properties. If these properties are fine-tuned, the hydrogels can be three-dimensionally bioprinted, to generate, for instance, constructs for cartilage repair. This study investigated whether hydrogels based on the polymer mentioned above with a 10% degree of methacrylation (M10P10) support cartilage formation by chondrocytes and whether the incorporation of methacrylated chondroitin sulfate (CSMA) or methacrylated hyaluronic acid (HAMA) can improve the mechanical properties, long-term stability, and printability. Chondrocyte-laden M10P10 hydrogels were cultured for 42 days to evaluate chondrogenesis. M10P10 hydrogels with or without polysaccharides were evaluated for their mechanical properties (before and after UV photo-cross-linking), degradation kinetics, and printability. Extensive cartilage matrix production occurred in M10P10 hydrogels, highlighting their potential for cartilage repair strategies. The incorporation of polysaccharides increased the storage modulus of polymer mixtures and decreased the degradation kinetics in cross-linked hydrogels. Addition of HAMA to M10P10 hydrogels improved printability and resulted in three-dimensional constructs with excellent cell viability. Hence, this novel combination of M10P10 with HAMA forms an interesting class of hydrogels for cartilage bioprinting. PMID:27171342

  18. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering.

    PubMed

    Mirahmadi, Fereshteh; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin

    2013-12-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber-hydrogel composite for GAG content and in two-layer electrospun fiber-hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering.

  19. Enhanced mechanical properties of thermosensitive chitosan hydrogel by silk fibers for cartilage tissue engineering.

    PubMed

    Mirahmadi, Fereshteh; Tafazzoli-Shadpour, Mohammad; Shokrgozar, Mohammad Ali; Bonakdar, Shahin

    2013-12-01

    Articular cartilage has limited repair capability following traumatic injuries and current methods of treatment remain inefficient. Reconstructing cartilage provides a new way for cartilage repair and natural polymers are often used as scaffold because of their biocompatibility and biofunctionality. In this study, we added degummed chopped silk fibers and electrospun silk fibers to the thermosensitive chitosan/glycerophosphate hydrogels to reinforce two hydrogel constructs which were used as scaffold for hyaline cartilage regeneration. The gelation temperature and gelation time of hydrogel were analyzed by the rheometer and vial tilting method. Mechanical characterization was measured by uniaxial compression, indentation and dynamic mechanical analysis assay. Chondrocytes were then harvested from the knee joint of the New Zealand white rabbits and cultured in constructs. The cell proliferation, viability, production of glycosaminoglycans and collagen type II were assessed. The results showed that mechanical properties of the hydrogel were significantly enhanced when a hybrid with two layers of electrospun silk fibers was made. The results of GAG and collagen type II in cell-seeded scaffolds indicate support of the chondrogenic phenotype for chondrocytes with a significant increase in degummed silk fiber-hydrogel composite for GAG content and in two-layer electrospun fiber-hydrogel composite for Col II. It was concluded that these two modified scaffolds could be employed for cartilage tissue engineering. PMID:24094188

  20. Differences in DNA Repair Capacity, Cell Death and Transcriptional Response after Irradiation between a Radiosensitive and a Radioresistant Cell Line.

    PubMed

    Borràs-Fresneda, Mireia; Barquinero, Joan-Francesc; Gomolka, Maria; Hornhardt, Sabine; Rössler, Ute; Armengol, Gemma; Barrios, Leonardo

    2016-06-01

    Normal tissue toxicity after radiotherapy shows variability between patients, indicating inter-individual differences in radiosensitivity. Genetic variation probably contributes to these differences. The aim of the present study was to determine if two cell lines, one radiosensitive (RS) and another radioresistant (RR), showed differences in DNA repair capacity, cell viability, cell cycle progression and, in turn, if this response could be characterised by a differential gene expression profile at different post-irradiation times. After irradiation, the RS cell line showed a slower rate of γ-H2AX foci disappearance, a higher frequency of incomplete chromosomal aberrations, a reduced cell viability and a longer disturbance of the cell cycle when compared to the RR cell line. Moreover, a greater and prolonged transcriptional response after irradiation was induced in the RS cell line. Functional analysis showed that 24 h after irradiation genes involved in "DNA damage response", "direct p53 effectors" and apoptosis were still differentially up-regulated in the RS cell line but not in the RR cell line. The two cell lines showed different response to IR and can be distinguished with cell-based assays and differential gene expression analysis. The results emphasise the importance to identify biomarkers of radiosensitivity for tailoring individualized radiotherapy protocols.

  1. 7,12-Dimethylbenz[a]anthracene exposure induces the DNA repair response in neonatal rat ovaries

    SciTech Connect

    Ganesan, Shanthi Bhattacharya, Poulomi Keating, Aileen F.

    2013-11-01

    7,12-Dimethylbenz[a]anthracene (DMBA) destroys ovarian follicles at all stages of development. This study investigated DMBA-induced DNA double strand break (DSB) formation with subsequent activation of the ovarian DNA repair response in models of pre-antral or pre-ovulatory follicle loss. Postnatal day (PND) 4 Fisher 344 (F344) rat ovaries were cultured for 4 days followed by single exposures of vehicle control (1% DMSO) or DMBA (12.5 nM or 75 nM) and maintained in culture for 4 or 8 days. Alternately, PND4 F344 rat ovaries were exposed to 1 μM DMBA at the start of culture for 2 days. Total RNA or protein was isolated, followed by qPCR or Western blotting to quantify mRNA or protein level, respectively. γH2AX and phosphorylated ATM were localized and quantified using immunofluorescence staining. DMBA exposure increased caspase 3 and γH2AX protein. Additionally, DMBA (12.5 nM and 1 μM) increased levels of mRNA encoding Atm, Xrcc6, Brca1 and Rad51. In contrast, Parp1 mRNA was decreased on d4 and increased on d8 of DMBA exposure, while PARP1 protein increased after 8 days of DMBA exposure. Total ATM increased in a concentration-dependent temporal pattern (75 nM d4; 12.5 nM d8), while pATM was localized in large primary and secondary follicles and increased after 8 days of 75 nM DMBA exposure compared to both control and 12.5 nM DMBA. These findings support that, despite some concentration effects, DMBA induces ovarian DNA damage and that DNA repair mechanisms are induced as a potential mechanism to prevent follicle loss. - Highlights: • DMBA exposure increases ovarian caspase-3 protein expression. • DMBA exposure increases the γH2AX protein in oocytes. • DMBA exposure activates a DNA repair response in the ovary.

  2. Evaluation of laser ablation of knee cartilage as an alternative to microfracture surgery: pilot investigations

    NASA Astrophysics Data System (ADS)

    Su, Erica; Wong, Brian J. F.; Sun, Hui; Juhasz, Tibor

    2010-02-01

    An emerging clinical treatment option for articular cartilage injury includes bone marrow stimulation techniques, such as microfracture, which has grown increasingly popular among athletes. During the microfracture procedure, the surgeon penetrates the subchondral bone with an awl and creates "microholes" deep enough to ensure bleeding from the bone marrow. This procedure triggers a spontaneous repair response that results in the formation of fibrocartilaginous repair tissue. This preliminary study aimed to evaluate the potential use of femtosecond lasers and Erbium:YAG lasers as alternatives to microfracture surgery of the knee by assessing the effects of ablation on bovine femoral condyles. Bovine femoral condyles were obtained and 8mm cube blocks were extracted. The specimen were ablated with various laser dosimetry parameters and observed using a high power dissecting microscope to examine the effects of the lasers. Further imaging with conventional histology (hematoxylin and eosin staining) was done to provide more accurate information. Preliminary results show some carbonization but demonstrate little thermal damage to surrounding tissues. The femtosecond laser offers a more precise and efficient ablation than the Erbium:YAG laser, but both are demonstrated to be possible alternatives to the surgical-skill dependent microfracture procedure.

  3. Age related changes and osteochondrosis in swine articular and epiphyseal cartilage: light ane electron microscopy.

    PubMed Central

    Bhatnagar, R; Christian, R G; Nakano, T; Aherne, F X; Thompson, J R

    1981-01-01

    Age related changes and osteochondrosis in swine were studied using light microscopy and electron microscopy in articular cartilage and light microscopy and epiphyseal cartilage of swine from three days to 30 weeks of age. Thickness, cellularity and vascularity of both the epiphyseal and articular cartilage, decreased as the swine aged. Osteochondrotic changes included formation of "plugs" of cartilage indicating localized failure of ossification and separation and space formation in epiphyseal cartilage. Eosinophilic streaks and space formation in epiphyseal cartilage was observed in relation to epiphyseal separation. Electron microscopy showed a continuous fibrillar layer on the surface of the cartilage corresponding to the lamina splendens of light microscopy. This layer increased in the thickness and showed accumulation of amorphous material between the fibrils with aging. In the matrix, the orientation and distribution of the collagen fibers changed with growth and thicker fibers with clear sub banding were more common in older age groups. Also, necrotic cells, glycogen containing bodies and cellular debris were noticed in the matrix of normal cartilage in old animals. Chondrocytes in the younger cartilage showed accumulation of organelles responsible for protein synthesis; while Golgi bodies, vesicles, lysosomes, well developed foot processes and other inclusions were noticed in older cartilage. Cartilage erosions had a clumped and disrupted lamina splendens on the surface and electron lucent patches in the ground substances of the matrix and chondrocyte cytoplasm. Images Fig. 1. Fig. 2 and 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. Fig. 8. Fig. 9. Fig. 10 and 11. Fig. 12. Fig. 13. Fig. 14. Fig. 15. Fig. 16. Fig. 17. Fig. 18. PMID:7260732

  4. Aggrecanases and cartilage matrix degradation

    PubMed Central

    Nagase, Hideaki; Kashiwagi, Masahide

    2003-01-01

    The loss of extracellular matrix macromolecules from the cartilage results in serious impairment of joint function. Metalloproteinases called 'aggrecanases' that cleave the Glu373–Ala374 bond of the aggrecan core protein play a key role in the early stages of cartilage destruction in rheumatoid arthritis and in osteoarthritis. Three members of the ADAMTS family of proteinases, ADAMTS-1, ADAMTS-4 and ADAMTS-5, have been identified as aggrecanases. Matrix metalloproteinases, which are also found in arthritic joints, cleave aggrecans, but at a distinct site from the aggrecanases (i.e. Asn341–Phe342). The present review discuss the enzymatic properties of the three known aggrecanases, the regulation of their activities, and their role in cartilage matrix breakdown during the development of arthritis in relation to the action of matrix metalloproteinases. PMID:12718749

  5. Collagen birefringence in skin repair in response to red polarized-laser therapy

    NASA Astrophysics Data System (ADS)

    da Silva, Daniela d. F. T.; Vidal, Benedicto d. C.; Zezell, Denise M.; Zorn, Telma M. T.; Núñez, Silvia C.; Ribeiro, Martha S.

    2006-03-01

    We use the optical path difference (OPD) technique to quantify the organization of collagen fibers during skin repair of full-thickness burns following low-intensity polarized laser therapy with two different polarization incidence vectors. Three burns are cryogenerated on the back of rats. Lesion L|| is irradiated using the electric field vector of the polarized laser radiation aligned in parallel with the rat's occipital-caudal direction. Lesion L⊥ is irradiated using the electric field vector of the polarized laser radiation aligned perpendicularly to the aforementioned orientation. Lesion C is untreated. A healthy area labeled H is also evaluated. The tissue samples are collected and processed for polarized light microscopy. The overall finding is that the OPD for collagen fibers depends on the electric field vector of the incident polarized laser radiation. No significant differences in OPDs are observed between L|| and H in the center, sides, and edges of the lesion. Lesions irradiated using the electric field vector of the polarized laser radiation aligned in parallel with the rat's occipital-caudal direction show higher birefringence, indicating that collagen bundles in these lesions are more organized.

  6. Cartilage collagen analysis in the chondrodystrophies.

    PubMed

    Horton, W A; Chou, J W; Machado, M A

    1985-09-01

    A simple and reproducible method for analyzing small samples of cartilage collagens was developed. Following extraction with guanidine HCl, the cartilage specimens were digested directly with CNBr and the resultant peptides separated by gel-permeation high-performance liquid chromatography. Resting cartilage collagen CNBr peptide maps differed from normal in two inherited chondrodystrophies, achondrogenesis II and spondyloepiphyseal dysplasia congenita. PMID:4053564

  7. Cold Atmospheric Plasma Modified Electrospun Scaffolds with Embedded Microspheres for Improved Cartilage Regeneration

    PubMed Central

    Zhu, Wei; Castro, Nathan J.; Cheng, Xiaoqian; Keidar, Michael; Zhang, Lijie Grace

    2015-01-01

    Articular cartilage is prone to degeneration and possesses extremely poor self-healing capacity due to inherent low cell density and the absence of a vasculature network. Tissue engineered cartilage scaffolds show promise for cartilage repair. However, there still remains a lack of ideal biomimetic tissue scaffolds which effectively stimulate cartilage regeneration with appropriate functional properties. Therefore, the objective of this study is to develop a novel biomimetic and bioactive electrospun cartilage substitute by integrating cold atmospheric plasma (CAP) treatment with sustained growth factor delivery microspheres. Specifically, CAP was applied to a poly(ε-caprolactone) electrospun scaffold with homogeneously distributed bioactive factors (transforming growth factor-β1 and bovine serum albumin) loaded poly(lactic-co-glycolic) acid microspheres. We have shown that CAP treatment renders electrospun scaffolds more hydrophilic thus facilitating vitronectin adsorption. More importantly, our results demonstrate, for the first time, CAP and microspheres can synergistically enhance stem cell growth as well as improve chondrogenic differentiation of human marrow-derived mesenchymal stem cells (such as increased glycosaminoglycan, type II collagen, and total collagen production). Furthermore, CAP can substantially enhance 3D cell infiltration (over two-fold increase in infiltration depth after 1 day of culture) in the scaffolds. By integrating CAP, sustained bioactive factor loaded microspheres, and electrospinning, we have fabricated a promising bioactive scaffold for cartilage regeneration. PMID:26222527

  8. An in vitro model for the pathological degradation of articular cartilage in osteoarthritis.

    PubMed

    Grenier, Stephanie; Bhargava, Madhu M; Torzilli, Peter A

    2014-02-01

    The objective of this study was to develop an in vitro cartilage degradation model that emulates the damage seen in early-stage osteoarthritis. To this end, cartilage explants were collagenase-treated to induce enzymatic degradation of collagen fibers and proteoglycans at the articular surface. To assess changes in mechanical properties, intact and degraded cartilage explants were subjected to a series of confined compression creep tests. Changes in extracellular matrix structure and composition were determined using biochemical and histological approaches. Our results show that collagenase-induced degradation increased the amount of deformation experienced by the cartilage explants under compression. An increase in apparent permeability as well as a decrease in instantaneous and aggregate moduli was measured following collagenase treatment. Histological analysis of degraded explants revealed the presence of surface fibrillation, proteoglycan depletion in the superficial and intermediate zones and loss of the lamina splendens. Collagen cleavage was confirmed by the Col II-3/4Cshort antibody. Degraded specimens experienced a significant decrease in proteoglycan content but maintained total collagen content. Repetitive testing of degraded samples resulted in the gradual collapse of the articular surface and the compaction of the superficial zone. Taken together, our data demonstrates that enzymatic degradation with collagenase can be used to emulate changes seen in early-stage osteoarthritis. Further, our in vitro model provides information on cartilage mechanics and insights on how matrix changes can affect cartilage's functional properties. More importantly, our model can be applied to develop and test treatment options for tissue repair. PMID:24360770

  9. An analysis of the integration between articular cartilage and nondegradable hydrogel using magnetic resonance imaging.

    PubMed

    Ramaswamy, Sharan; Wang, Dong-An; Fishbein, Kenneth W; Elisseeff, Jennifer H; Spencer, Richard G

    2006-04-01

    A hydrogel is a highly hydrated polymer gel suitable for use as a scaffold for tissue engineering. One important application is to the repair of cartilage defects due to injury or osteoarthritis. Integration of the hydrogel with surrounding tissue is critical for the long-term functionality of the implant; however direct visualization of integration is difficult and invasive. Accordingly, we used MRI to noninvasively investigate the integration of hydrogel in cartilage. Two integration methods were assessed: (1) cartilage-initiated and (2) chemical, using chondroitin sulphate-methacrylate-aldehyde (CS-MA-ald) as an adhesive. These were compared to a control group, that is, standard, nonintegrated hydrogel photopolymerization. Spatial variation of the transverse relaxation time, T(2), across the transition region was used to determine the effectiveness of integration. In the CS-MA-ald group only, two interfaces were found. This provides evidence of an intermediate adhesive layer between hydrogel and cartilage. Second, the thickness of the transition region between hydrogel to cartilage in the CS-MA-ald group was 1.32 mm as compared to 1.20 mm and 1.17 mm in the tissue-initiated and nonintegrated groups, respectively. We interpret this as a more gradual transition region of hydrogel to cartilage and hence a greater degree of integration when an adhesive layer is present.

  10. Cold Atmospheric Plasma Modified Electrospun Scaffolds with Embedded Microspheres for Improved Cartilage Regeneration.

    PubMed

    Zhu, Wei; Castro, Nathan J; Cheng, Xiaoqian; Keidar, Michael; Zhang, Lijie Grace

    2015-01-01

    Articular cartilage is prone to degeneration and possesses extremely poor self-healing capacity due to inherent low cell density and the absence of a vasculature network. Tissue engineered cartilage scaffolds show promise for cartilage repair. However, there still remains a lack of ideal biomimetic tissue scaffolds which effectively stimulate cartilage regeneration with appropriate functional properties. Therefore, the objective of this study is to develop a novel biomimetic and bioactive electrospun cartilage substitute by integrating cold atmospheric plasma (CAP) treatment with sustained growth factor delivery microspheres. Specifically, CAP was applied to a poly(ε-caprolactone) electrospun scaffold with homogeneously distributed bioactive factors (transforming growth factor-β1 and bovine serum albumin) loaded poly(lactic-co-glycolic) acid microspheres. We have shown that CAP treatment renders electrospun scaffolds more hydrophilic thus facilitating vitronectin adsorption. More importantly, our results demonstrate, for the first time, CAP and microspheres can synergistically enhance stem cell growth as well as improve chondrogenic differentiation of human marrow-derived mesenchymal stem cells (such as increased glycosaminoglycan, type II collagen, and total collagen production). Furthermore, CAP can substantially enhance 3D cell infiltration (over two-fold increase in infiltration depth after 1 day of culture) in the scaffolds. By integrating CAP, sustained bioactive factor loaded microspheres, and electrospinning, we have fabricated a promising bioactive scaffold for cartilage regeneration. PMID:26222527

  11. Effect of Human Adipose Tissue Mesenchymal Stem Cells on the Regeneration of Ovine Articular Cartilage.

    PubMed

    Zorzi, Alessandro R; Amstalden, Eliane M I; Plepis, Ana Maria G; Martins, Virginia C A; Ferretti, Mario; Antonioli, Eliane; Duarte, Adriana S S; Luzo, Angela C M; Miranda, João B

    2015-11-09

    Cell therapy is a promising approach to improve cartilage healing. Adipose tissue is an abundant and readily accessible cell source. Previous studies have demonstrated good cartilage repair results with adipose tissue mesenchymal stem cells in small animal experiments. This study aimed to examine these cells in a large animal model. Thirty knees of adult sheep were randomly allocated to three treatment groups: CELLS (scaffold seeded with human adipose tissue mesenchymal stem cells), SCAFFOLD (scaffold without cells), or EMPTY (untreated lesions). A partial thickness defect was created in the medial femoral condyle. After six months, the knees were examined according to an adaptation of the International Cartilage Repair Society (ICRS 1) score, in addition to a new Partial Thickness Model scale and the ICRS macroscopic score. All of the animals completed the follow-up period. The CELLS group presented with the highest ICRS 1 score (8.3 ± 3.1), followed by the SCAFFOLD group (5.6 ± 2.2) and the EMPTY group (5.2 ± 2.4) (p = 0.033). Other scores were not significantly different. These results suggest that human adipose tissue mesenchymal stem cells promoted satisfactory cartilage repair in the ovine model.

  12. Macrophage phagocytosis alters the MRI signal of ferumoxytol-labeled mesenchymal stromal cells in cartilage defects

    NASA Astrophysics Data System (ADS)

    Nejadnik, Hossein; Lenkov, Olga; Gassert, Florian; Fretwell, Deborah; Lam, Isaac; Daldrup-Link, Heike E.

    2016-05-01

    Human mesenchymal stem cells (hMSCs) are a promising tool for cartilage regeneration in arthritic joints. hMSC labeling with iron oxide nanoparticles enables non-invasive in vivo monitoring of transplanted cells in cartilage defects with MR imaging. Since graft failure leads to macrophage phagocytosis of apoptotic cells, we evaluated in vitro and in vivo whether nanoparticle-labeled hMSCs show distinct MR signal characteristics before and after phagocytosis by macrophages. We found that apoptotic nanoparticle-labeled hMSCs were phagocytosed by macrophages while viable nanoparticle-labeled hMSCs were not. Serial MRI scans of hMSC transplants in arthritic joints of recipient rats showed that the iron signal of apoptotic, nanoparticle-labeled hMSCs engulfed by macrophages disappeared faster compared to viable hMSCs. This corresponded to poor cartilage repair outcomes of the apoptotic hMSC transplants. Therefore, rapid decline of iron MRI signal at the transplant site can indicate cell death and predict incomplete defect repair weeks later. Currently, hMSC graft failure can be only diagnosed by lack of cartilage defect repair several months after cell transplantation. The described imaging signs can diagnose hMSC transplant failure more readily, which could enable timely re-interventions and avoid unnecessary follow up studies of lost transplants.

  13. Potential of human embryonic stem cells in cartilage tissue engineering and regenerative medicine.

    PubMed

    Toh, Wei Seong; Lee, Eng Hin; Cao, Tong

    2011-09-01

    The current surgical intervention of using autologous chondrocyte implantation (ACI) for cartilage repair is associated with several problems such as donor site morbidity, de-differentiation upon expansion and fibrocartilage repair following transplantation. This has led to exploration of the use of stem cells as a model for chondrogenic differentiation as well as a potential source of chondrogenic cells for cartilage tissue engineering and repair. Embryonic stem cells (ESCs) are advantageous, due to their unlimited self-renewal and pluripotency, thus representing an immortal cell source that could potentially provide an unlimited supply of chondrogenic cells for both cell and tissue-based therapies and replacements. This review aims to present an overview of emerging trends of using ESCs in cartilage tissue engineering and regenerative medicine. In particular, we will be focusing on ESCs as a promising cell source for cartilage regeneration, the various strategies and approaches employed in chondrogenic differentiation and tissue engineering, the associated outcomes from animal studies, and the challenges that need to be overcome before clinical application is possible.

  14. Macrophage phagocytosis alters the MRI signal of ferumoxytol-labeled mesenchymal stromal cells in cartilage defects

    PubMed Central

    Nejadnik, Hossein; Lenkov, Olga; Gassert, Florian; Fretwell, Deborah; Lam, Isaac; Daldrup-Link, Heike E.

    2016-01-01

    Human mesenchymal stem cells (hMSCs) are a promising tool for cartilage regeneration in arthritic joints. hMSC labeling with iron oxide nanoparticles enables non-invasive in vivo monitoring of transplanted cells in cartilage defects with MR imaging. Since graft failure leads to macrophage phagocytosis of apoptotic cells, we evaluated in vitro and in vivo whether nanoparticle-labeled hMSCs show distinct MR signal characteristics before and after phagocytosis by macrophages. We found that apoptotic nanoparticle-labeled hMSCs were phagocytosed by macrophages while viable nanoparticle-labeled hMSCs were not. Serial MRI scans of hMSC transplants in arthritic joints of recipient rats showed that the iron signal of apoptotic, nanoparticle-labeled hMSCs engulfed by macrophages disappeared faster compared to viable hMSCs. This corresponded to poor cartilage repair outcomes of the apoptotic hMSC transplants. Therefore, rapid decline of iron MRI signal at the transplant site can indicate cell death and predict incomplete defect repair weeks later. Currently, hMSC graft failure can be only diagnosed by lack of cartilage defect repair several months after cell transplantation. The described imaging signs can diagnose hMSC transplant failure more readily, which could enable timely re-interventions and avoid unnecessary follow up studies of lost transplants. PMID:27174199

  15. Effect of Human Adipose Tissue Mesenchymal Stem Cells on the Regeneration of Ovine Articular Cartilage

    PubMed Central

    Zorzi, Alessandro R.; Amstalden, Eliane M. I.; Plepis, Ana Maria G.; Martins, Virginia C. A.; Ferretti, Mario; Antonioli, Eliane; Duarte, Adriana S. S.; Luzo, Angela C. M.; Miranda, João B.

    2015-01-01

    Cell therapy is a promising approach to improve cartilage healing. Adipose tissue is an abundant and readily accessible cell source. Previous studies have demonstrated good cartilage repair results with adipose tissue mesenchymal stem cells in small animal experiments. This study aimed to examine these cells in a large animal model. Thirty knees of adult sheep were randomly allocated to three treatment groups: CELLS (scaffold seeded with human adipose tissue mesenchymal stem cells), SCAFFOLD (scaffold without cells), or EMPTY (untreated lesions). A partial thickness defect was created in the medial femoral condyle. After six months, the knees were examined according to an adaptation of the International Cartilage Repair Society (ICRS 1) score, in addition to a new Partial Thickness Model scale and the ICRS macroscopic score. All of the animals completed the follow-up period. The CELLS group presented with the highest ICRS 1 score (8.3 ± 3.1), followed by the SCAFFOLD group (5.6 ± 2.2) and the EMPTY group (5.2 ± 2.4) (p = 0.033). Other scores were not significantly different. These results suggest that human adipose tissue mesenchymal stem cells promoted satisfactory cartilage repair in the ovine model. PMID:26569221

  16. MRI EVALUATION OF KNEE CARTILAGE

    PubMed Central

    Rodrigues, Marcelo Bordalo; Camanho, Gilberto Luís

    2015-01-01

    Through the ability of magnetic resonance imaging (MRI) to characterize soft tissue noninvasively, it has become an excellent method for evaluating cartilage. The development of new and faster methods allowed increased resolution and contrast in evaluating chondral structure, with greater diagnostic accuracy. In addition, physiological techniques for cartilage assessment that can detect early changes before the appearance of cracks and erosion have been developed. In this updating article, the various techniques for chondral assessment using knee MRI will be discussed and demonstrated. PMID:27022562

  17. Proliferation rate but not mismatch repair affects the long-term response of colon carcinoma cells to 5FU treatment.

    PubMed

    Choudhary, B; Hanski, M L; Zeitz, M; Hanski, C

    2012-07-01

    The role of mismatch repair (MMR) in the response of colon carcinoma cells to 5-fluorouracil (5FU) is not well understood. In most of the in vitro studies only short-term response was investigated. We focussed here on the influence of MMR status on the mechanism of the short- and long-term response to clinically relevant 5FU concentrations by using isogenic or semiisogenic cell line pairs expressing/nonexpressing the hMLH1 protein, an important component of the MMR system. We show that the lower survival of MMR-proficient than of MMR-deficient cells in the clonogenic survival assay is due to a more frequent early cell arrest and to subsequent senescence. By contrast, the long-term cell growth after treatment, which is also affected by long-term arrest and senescence, is independent from the MMR status. The overall effect on the long-term cell growth is a cumulative result of cell proliferation rate-dependent growth inhibition, apoptosis and necrotic cell death. The main long-term cytotoxic effect of 5FU is the inhibition of growth while apoptosis and the necrotic cell death are minor contributions.

  18. A role of iron ions in the SOS DNA repair response induced by nitric oxide in Escherichia coli.

    PubMed

    Stupakova, M V; Lobysheva, I I; Mikoyan, V D; Vanin, A F; Vasilieva, S V

    2000-06-01

    An induction of the SOS DNA repair response by physiological nitric oxide donors (dinitrosyl iron complexes (DNIC) with thiols and S-nitrosothiols (RSNO)) was studied in E. coli cells. DNIC with thiols were the most effective SOS-inducers. Being more toxic, RSNO mediated a similar response at 10-100 microM, but they were inactive at concentrations above 0.5 mM. Pretreatment of the cells with chelating agents, o-phenanthroline and picolinic acid, prevented induction of the SOS response by all NO-donors used and led to a decrease in the DNIC-type EPR signal that appeared after incubation of the cells with DNIC or S-nitrosoglutathione (GSNO). Analysis of these effects revealed a dual role of iron ions in reactivity and toxicity of the NO-donating agents. On one hand, they could stabilize GSNO in the form of less toxic DNIC, and, on the other hand, they took part in the formation of the SOS-inducing signal by NO-donating agents. PMID:10887288

  19. Differences in DNA Repair Capacity, Cell Death and Transcriptional Response after Irradiation between a Radiosensitive and a Radioresistant Cell Line

    PubMed Central

    Borràs-Fresneda, Mireia; Barquinero, Joan-Francesc; Gomolka, Maria; Hornhardt, Sabine; Rössler, Ute; Armengol, Gemma; Barrios, Leonardo

    2016-01-01

    Normal tissue toxicity after radiotherapy shows variability between patients, indicating inter-individual differences in radiosensitivity. Genetic variation probably contributes to these differences. The aim of the present study was to determine if two cell lines, one radiosensitive (RS) and another radioresistant (RR), showed differences in DNA repair capacity, cell viability, cell cycle progression and, in turn, if this response could be characterised by a differential gene expression profile at different post-irradiation times. After irradiation, the RS cell line showed a slower rate of γ-H2AX foci disappearance, a higher frequency of incomplete chromosomal aberrations, a reduced cell viability and a longer disturbance of the cell cycle when compared to the RR cell line. Moreover, a greater and prolonged transcriptional response after irradiation was induced in the RS cell line. Functional analysis showed that 24 h after irradiation genes involved in “DNA damage response”, “direct p53 effectors” and apoptosis were still differentially up-regulated in the RS cell line but not in the RR cell line. The two cell lines showed different response to IR and can be distinguished with cell-based assays and differential gene expression analysis. The results emphasise the importance to identify biomarkers of radiosensitivity for tailoring individualized radiotherapy protocols. PMID:27245205

  20. Potential benefits and limitations of utilizing chondroprogenitors in cell-based cartilage therapy

    PubMed Central

    Jayasuriya, Chathuraka T.

    2016-01-01

    Chondroprogenitor cells are a subpopulation of multipotent progenitors that are primed for chondrogenesis. They are believed to have the biological repertoire to be ideal for cell-based cartilage therapy. In addition to summarizing recent advances in chondroprogenitor cell characterization, this review discusses the projected pros and cons of utilizing chondroprogenitors in regenerative medicine and compares them to that of preexisting methods, including autologous chondrocyte implantation (ACI) and the utilization of bone marrow derived mesenchymal stem cells (MSCs) for the purpose of cartilage tissue repair. PMID:26075411

  1. Potential benefits and limitations of utilizing chondroprogenitors in cell-based cartilage therapy.

    PubMed

    Jayasuriya, Chathuraka T; Chen, Qian

    2015-01-01

    Chondroprogenitor cells are a subpopulation of multipotent progenitors that are primed for chondrogenesis. They are believed to have the biological repertoire to be ideal for cell-based cartilage therapy. In addition to summarizing recent advances in chondroprogenitor cell characterization, this review discusses the projected pros and cons of utilizing chondroprogenitors in regenerative medicine and compares them with that of pre-existing methods, including autologous chondrocyte implantation (ACI) and the utilization of bone marrow derived mesenchymal stem cells (MSCs) for the purpose of cartilage tissue repair.

  2. State of the art and future perspectives of articular cartilage regeneration: a focus on adipose-derived stem cells and platelet-derived products.

    PubMed

    Hildner, F; Albrecht, C; Gabriel, C; Redl, H; van Griensven, M

    2011-04-01

    Trauma, malposition and age-related degeneration of articular cartilage often result in severe lesions that do not heal spontaneously. Many efforts over the last centuries have been undertaken to support cartilage healing, with approaches ranging from symptomatic treatment to structural cartilage regeneration. Microfracture and matrix-associated autologous chondrocyte transplantation (MACT) can be regarded as one of the most effective techniques available today to treat traumatic cartilage defects. Research is focused on the development of new biomaterials, which are intended to provide optimized physical and biochemical conditions for cell proliferation and cartilage synthesis. New attempts have also been undertaken to replace chondrocytes with cells that are more easily available and cause less donor site morbidity, e.g. adipose derived stem cells (ASC). The number of in vitro studies on adult stem cells has rapidly increased during the last decade, indicating that many variables have yet to be optimized to direct stem cells towards the desired lineage. The present review gives an overview of the difficulties of cartilage repair and current cartilage repair techniques. Moreover, it reviews new fields of cartilage tissue engineering, including stem cells, co-cultures and platelet-rich plasma (PRP).

  3. Conversational Repair Strategies in Response to Requests for Clarification in Typically Developing Jordanian Children Ages 4;0-6;0 Years

    ERIC Educational Resources Information Center

    Kamal, Sana M.; Haj-Tas, Maisa A.

    2014-01-01

    Conversational repairs are an important pragmatic language skill. We identified types of responses to requests for clarification and their frequencies in typically developing 4;0-6;0-year-old Jordanian children. This study was motivated by the fact that there are no Arabic data regarding this issue and by the limited range of forms of requests for…

  4. Biaxial Mechanical Evaluation of Absorbable and Nonabsorbable Synthetic Surgical Meshes Used for Hernia Repair: Physiological Loads Modify Anisotropy Response.

    PubMed

    Cordero, A; Hernández-Gascón, B; Pascual, G; Bellón, J M; Calvo, B; Peña, E

    2016-07-01

    The aim of this study was to obtain information about the mechanical properties of six meshes commonly used for hernia repair (Surgipro(®), Optilene(®), Infinit(®), DynaMesh(®), Ultrapro™ and TIGR(®)) by planar biaxial tests. Stress-stretch behavior and equibiaxial stiffness were evaluated, and the anisotropy was determined by testing. In particular, equibiaxial test (equal simultaneous loading in both directions) and biaxial test (half of the load in one direction following the Laplace law) were selected as a representation of physiologically relevant loads. The majority of the meshes displayed values in the range of 8 and 18 (N/mm) in each direction for equibiaxial stiffness (tangent modulus under equibiaxial load state in both directions), while a few achieved 28 and 50 (N/mm) (Infinit (®) and TIGR (®)). Only the Surgipro (®) mesh exhibited planar isotropy, with similar mechanical properties regardless of the direction of loading, and an anisotropy ratio of 1.18. Optilene (®), DynaMesh (®), Ultrapro (®) and TIGR (®) exhibited moderate anisotropy with ratios of 1.82, 1.84, 2.17 and 1.47, respectively. The Infinit (®) scaffold exhibited very high anisotropy with a ratio of 3.37. These trends in material anisotropic response changed during the physiological state in the human abdominal wall, i.e. T:0.5T test, which the meshes were loaded in one direction with half the load used in the other direction. The Surgipro (®) mesh increased its anisotropic response (Anis[Formula: see text] = 0.478) and the materials that demonstrated moderate and high anisotropic responses during multiaxial testing presented a quasi-isotropic response, especially the Infinit(®) mesh that decreased its anisotropic response from 3.369 to 1.292. PMID:26620778

  5. Biaxial Mechanical Evaluation of Absorbable and Nonabsorbable Synthetic Surgical Meshes Used for Hernia Repair: Physiological Loads Modify Anisotropy Response.

    PubMed

    Cordero, A; Hernández-Gascón, B; Pascual, G; Bellón, J M; Calvo, B; Peña, E

    2016-07-01

    The aim of this study was to obtain information about the mechanical properties of six meshes commonly used for hernia repair (Surgipro(®), Optilene(®), Infinit(®), DynaMesh(®), Ultrapro™ and TIGR(®)) by planar biaxial tests. Stress-stretch behavior and equibiaxial stiffness were evaluated, and the anisotropy was determined by testing. In particular, equibiaxial test (equal simultaneous loading in both directions) and biaxial test (half of the load in one direction following the Laplace law) were selected as a representation of physiologically relevant loads. The majority of the meshes displayed values in the range of 8 and 18 (N/mm) in each direction for equibiaxial stiffness (tangent modulus under equibiaxial load state in both directions), while a few achieved 28 and 50 (N/mm) (Infinit (®) and TIGR (®)). Only the Surgipro (®) mesh exhibited planar isotropy, with similar mechanical properties regardless of the direction of loading, and an anisotropy ratio of 1.18. Optilene (®), DynaMesh (®), Ultrapro (®) and TIGR (®) exhibited moderate anisotropy with ratios of 1.82, 1.84, 2.17 and 1.47, respectively. The Infinit (®) scaffold exhibited very high anisotropy with a ratio of 3.37. These trends in material anisotropic response changed during the physiological state in the human abdominal wall, i.e. T:0.5T test, which the meshes were loaded in one direction with half the load used in the other direction. The Surgipro (®) mesh increased its anisotropic response (Anis[Formula: see text] = 0.478) and the materials that demonstrated moderate and high anisotropic responses during multiaxial testing presented a quasi-isotropic response, especially the Infinit(®) mesh that decreased its anisotropic response from 3.369 to 1.292.

  6. Arthroscopic optical coherence tomography provides detailed information on articular cartilage lesions in horses.

    PubMed

    te Moller, N C R; Brommer, H; Liukkonen, J; Virén, T; Timonen, M; Puhakka, P H; Jurvelin, J S; van Weeren, P R; Töyräs, J

    2013-09-01

    Arthroscopy enables direct inspection of the articular surface, but provides no information on deeper cartilage layers. Optical coherence tomography (OCT), based on measurement of reflection and backscattering of light, is a diagnostic technique used in cardiovascular surgery and ophthalmology. It provides cross-sectional images at resolutions comparable to that of low-power microscopy. The aim of this study was to determine if OCT is feasible for advanced clinical assessment of lesions in equine articular cartilage during diagnostic arthroscopy. Diagnostic arthroscopy of 36 metacarpophalangeal joints was carried out ex vivo. Of these, 18 joints with varying degrees of cartilage damage were selected, wherein OCT arthroscopy was conducted using an OCT catheter (diameter 0.9 mm) inserted through standard instrument portals. Five sites of interest, occasionally supplemented with other locations where defects were encountered, were arthroscopically graded according to the International Cartilage Repair Society (ICRS) classification system. The same sites were evaluated qualitatively (ICRS classification and morphological description of the lesions) and quantitatively (measurement of cartilage thickness) on OCT images. OCT provided high resolution images of cartilage enabling determination of cartilage thickness. Comparing ICRS grades determined by both arthroscopy and OCT revealed poor agreement. Furthermore, OCT visualised a spectrum of lesions, including cavitation, fibrillation, superficial and deep clefts, erosion, ulceration and fragmentation. In addition, with OCT the arthroscopically inaccessible area between the dorsal MC3 and P1 was reachable in some cases. Arthroscopically-guided OCT provided more detailed and quantitative information on the morphology of articular cartilage lesions than conventional arthroscopy. OCT could therefore improve the diagnostic value of arthroscopy in equine orthopaedic surgery. PMID:23810744

  7. Applications of Chondrocyte-Based Cartilage Engineering: An Overview

    PubMed Central

    Eo, Seong-Hui; Abbas, Qamar; Ahmed, Madiha

    2016-01-01

    Chondrocytes are the exclusive cells residing in cartilage and maintain the functionality of cartilage tissue. Series of biocomponents such as different growth factors, cytokines, and transcriptional factors regulate the mesenchymal stem cells (MSCs) differentiation to chondrocytes. The number of chondrocytes and dedifferentiation are the key limitations in subsequent clinical application of the chondrocytes. Different culture methods are being developed to overcome such issues. Using tissue engineering and cell based approaches, chondrocytes offer prominent therapeutic option specifically in orthopedics for cartilage repair and to treat ailments such as tracheal defects, facial reconstruction, and urinary incontinence. Matrix-assisted autologous chondrocyte transplantation/implantation is an improved version of traditional autologous chondrocyte transplantation (ACT) method. An increasing number of studies show the clinical significance of this technique for the chondral lesions treatment. Literature survey was carried out to address clinical and functional findings by using various ACT procedures. The current study was conducted to study the pharmacological significance and biomedical application of chondrocytes. Furthermore, it is inferred from the present study that long term follow-up studies are required to evaluate the potential of these methods and specific positive outcomes.

  8. iPS cell technologies and cartilage regeneration.

    PubMed

    Tsumaki, Noriyuki; Okada, Minoru; Yamashita, Akihiro

    2015-01-01

    Articular cartilage covers the ends of bone and provides shock absorption and lubrication to the diarthrodial joints. Cartilage has a limited capacity for repair when injured, and there is a need for cell sources for chondrocytes that can be transplanted as part of a regenerative medicine approach. Induced pluripotent stem cells (iPSCs) have pluripotency and the potential for self-renewal similar to embryonic stem cells (ESC