Neocartilage formation from mesenchymal stem cells grown in type II collagen-hyaluronan composite scaffolds

Promotion of diced cartilage survival and regeneration with grafting of small intestinal submucosa loaded with urine-derived stem cells

Cartilage absorption and calcification are prone to occur after the implantation of diced cartilage wrapped with autologous materials, as well as prolong the operation time, aggravate surgical trauma and postoperative pain during the acquisition process. Small intestinal submucosa (SIS) has suitable toughness and excellent degradability, which has been widely used in the clinic. Urine-derived stem cells (USCs), as a new type of stem cells, have multi-directional differentiation potential. In this study, we attempt to create the tissue engineering membrane material, termed USCs-SIS (U-SIS), and wrap the diced cartilage with it, assuming that they can promote the survival and regeneration of cartilage. In this study, after co-culture with the SIS and U-SIS, the proliferation, migration and chondrogenesis ability of the auricular-derived chondrocyte cells (ACs) were significantly improved. Further, the expression levels of chondrocyte phenotype-related genes were up-regulated, whilst that of dedifferentiated genes was down-regulated. The signal pathway proteins (Wnt3a and Wnt5a) were also participated in regulation of chondrogenesis. In vivo, compared with perichondrium, the diced cartilage wrapped with the SIS and U-SIS attained higher survival rate, less calcification and absorption in both short and long terms. Particularly, USCs promoted chondrogenesis and modulated local immune responses via paracrine pathways. In conclusion, SIS have the potential to be a new choice of membrane material for diced cartilage graft. U-SIS can enhance survival and regeneration of diced cartilage as a bioactive membrane material.

Irrigating degradation properties of silk fibroin-collagen type II composite cartilage scaffold in vitro and in vivo

Silk fibroin-collagen type II scaffolds are promising in cartilage tissue engineering due to their suitable biological functionality to promote proliferation of chondrocytes in vitro. However, their degradation properties, which are of crucial importance as scaffold degradation should consistent with the new tissue formation process, are still unknown. In this study, degradability of silk fibroin-collagen type II cartilage scaffolds was probed both in vitro and in vivo. In vitro degradation experiments show that the scaffolds decreased 32.25 % ± 0.62 %, 34.27 % ± 0.96 %, 36.27 % ± 2.39 % in weight after 8 weeks of degradation at the irrigation velocity of 0 mL/min, 7.89 mL/min and 15.79 mL/min. The degradation ratio, which increases with time and increasing irrigation velocity, is described by combining the built mathematic model and finite element modeling method. The scaffolds after 8 weeks of degradation in vitro keep their mechanical structural integrity to support new tissues. In vivo degradation experiments conducted in rabbits further show that the scaffolds degrade gradually, be absorbed with time and finally collapse in structure. The degradation process is accompanied by the growth of fibrous tissues and the scaffold is filled by fibrous tissues after 12 weeks of implantation. Immunohistology analysis shows that the inflammation caused by scaffolds is controllable and gradually alleviates with time. To sum up, silk fibroin-collagen type II cartilage scaffolds, which show suitable mechanical properties and biocompatibility during degradation in vitro and in vivo, have great potential in cartilage repair. The novelty of the study is that it not only introduces a mathematical model to predict the irrigation degradation ratio, but also provides experimental degradation data support for clinical application of silk fibroin-collagen type II cartilage scaffolds.

Allogenic Use of Human Placenta-Derived Stromal Cells as a Highly Active Subtype of Mesenchymal Stromal Cells for Cell-Based Therapies

The application of mesenchymal stromal cells (MSCs) from different sources, including bone marrow (BM, bmMSCs), adipose tissue (atMSCs), and human term placenta (hPSCs) has been proposed for various clinical purposes. Accumulated evidence suggests that the activity of the different MSCs is indirect and associated with paracrine release of pro-regenerative and anti-inflammatory factors. A major limitation of bmMSCs-based treatment for autologous application is the limited yield of cells harvested from BM and the invasiveness of the procedure. Similar effects of autologous and allogeneic MSCs isolated from various other tissues were reported. The easily available fresh human placenta seems to represent a preferred source for harvesting abundant numbers of human hPSCs for allogenic use. Cells derived from the neonate tissues of the placenta (f-hPSC) can undergo extended expansion with a low risk of senescence. The low expression of HLA class I and II on f-hPSCs reduces the risk of rejection in allogeneic or xenogeneic applications in normal immunocompetent hosts. The main advantage of hPSCs-based therapies seems to lie in the secretion of a wide range of pro-regenerative and anti-inflammatory factors. This renders hPSCs as a very competent cell for therapy in humans or animal models. This review summarizes the therapeutic potential of allogeneic applications of f-hPSCs, with reference to their indirect pro-regenerative and anti-inflammatory effects and discusses clinical feasibility studies.

In Vivo Cartilage Regeneration with Cell-Seeded Natural Biomaterial Scaffold Implants: 15-Year Study

Articular cartilage can be easily damaged from human's daily activities, leading to inflammation and to osteoarthritis, a situation that can diminish the patients' quality of life. For larger cartilage defects, scaffolds are employed to provide cells the appropriate three-dimensional environment to proliferate and differentiate into healthy cartilage tissue. Natural biomaterials used as scaffolds, attract researchers' interest because of their relative nontoxic nature, their abundance as natural products, their easy combination with other materials, and the relative easiness to establish Marketing Authorization. The last 15 years were chosen to review, document, and elucidate the developments on cell-seeded natural biomaterials for articular cartilage treatment in vivo. The parameters of the experimental designs and their results were all documented and presented. Considerations about the newly formed cartilage and the treatment of cartilage defects were discussed, along with difficulties arising when applying natural materials, research limitations, and tissue engineering approaches for hyaline cartilage regeneration.

Head to Knee: Cranial Neural Crest-Derived Cells as Promising Candidates for Human Cartilage Repair

A large array of therapeutic procedures is available to treat cartilage disorders caused by trauma or inflammatory disease. Most are invasive and may result in treatment failure or development of osteoarthritis due to extensive cartilage damage from repeated surgery. Despite encouraging results of early cell therapy trials that used chondrocytes collected during arthroscopic surgery, these approaches have serious disadvantages, including morbidity associated with cell harvesting and low predictive clinical outcomes. To overcome these limitations, adult stem cells derived from bone marrow and subsequently from other tissues are now considered as preferred sources of cells for cartilage regeneration. Moreover, with new evidence showing that the choice of cell source is one of the most important factors for successful cell therapy, there is growing interest in neural crest-derived cells in both the research and clinical communities. Neural crest-derived cells such as nasal chondrocytes and oral stem cells that exhibit chondrocyte-like properties seem particularly promising in cartilage repair. Here, we review the types of cells currently available for cartilage cell therapy, including articular chondrocytes and various mesenchymal stem cells, and then highlight recent developments in the use of neural crest-derived chondrocytes and oral stem cells for repair of cartilage lesions.

Mesothelial Stem Cells and Stromal Vascular Fraction for Skin Rejuvenation

The use of stem cells in regenerative medicine and specifically facial rejuvenation is thought provoking and controversial. Today there is increased emphasis on tissue engineering and regenerative medicine, which translates into a need for a reliable source of stem cells in addition to biomaterial scaffolds and cytokine growth factors. Adipose tissue is currently recognized as an accessible and abundant source for adult stem cells. Cellular therapies and tissue engineering are still in their infancy, and additional basic science and preclinical studies are needed before cosmetic and reconstructive surgical applications can be routinely undertaken and satisfactory levels of patient safety achieved.

Chondrogenic differentiation of BMSCs encapsulated in chondroinductive polysaccharide/collagen hybrid hydrogels

Although BMSC-based therapy is one of the most front-line technologies for cartilage repair, it is still a big challenge to attain ideal niches for BMSC chondrogenic differentiation. In this study, we developed hyaluronate and chondroitin sulfate derivatives to prepare covalently crosslinked polysaccharide hydrogels. Based on these binary hydrogels, collagen was added to prepare ternary hybrid hydrogels and its effect on encapsulated BMSCs was studied. After culturing with different cell densities in vitro without the addition of growth factors for 3 weeks, the chondrogenesis of BMSCs was evaluated by CLSM, mechanical testing, histological staining, immunohistochemical staining and gene expression. The results indicated that BMSCs in high cell density (50 million per mL) cell-laden constructs had a more obvious chondrogenic phenotype than those in low cell density ones (5 million per mL). However, the components of hydrogels had a significant influence on chondrogenic differentiation. With the addition of collagen, the BMSCs in ternary hybrid hydrogels showed more significant chondrogenesis, possessing with more amounts of secreted glycosaminoglycans (GAGs) and type II collagen deposition, higher mechanical properties and chondrogenic gene expression over 3 weeks of culture in vitro. It can be concluded that the bioactive collagen is beneficial to the chondrogenesis of BMSCs. This hybrid hydrogels deserve further studies to have a prospective application in tissue engineering for cartilage defect repair.

Potential of silk fibroin/chondrocyte constructs of muga silkworm Antheraea assamensis for cartilage tissue engineering

Articular cartilage damage represents one of the most perplexing clinical problems of musculoskeletal therapeutics due to its limited self-repair and regenerative capabilities. In this study, 3D porous silk fibroin scaffolds derived from non-mulberry muga silkworm Antheraea assamensis were fabricated and examined for their ability to support cartilage tissue engineering. Additionally, Bombyx mori and Philosamia ricini silk fibroin scaffolds were utilized for comparative studies. Herein, the fabricated scaffolds were thoroughly characterized and compared for cartilaginous tissue formation within the silk fibroin scaffolds seeded with primary porcine chondrocytes and cultured in vitro for 2 weeks. Surface morphology and structural conformation studies revealed the highly interconnected porous structure (pore size 80-150 μm) with enhanced stability within their structure. The fabricated scaffolds demonstrated improved mechanical properties and were followed-up with sequential experiments to reveal improved thermal and degradation properties. Silk fibroin scaffolds of A. assamensis and P. ricini supported better chondrocyte attachment and proliferation as indicated by metabolic activities and fluorescence microscopic studies. Biochemical analysis demonstrated significantly higher production of sulphated glycosaminoglycans (sGAGs) and type II collagen in A. assamensis silk fibroin scaffolds followed by P. ricini and B. mori scaffolds (p < 0.001). Furthermore, histochemistry and immunohistochemical studies indicated enhanced accumulation of sGAGs and expression of collagen II. Moreover, the scaffolds in a subcutaneous model of rat demonstrated in vivo biocompatibility after 8 weeks of implantation. Taken together, these results demonstrate the positive attributes from the non-mulberry silk fibroin scaffold of A. assamensis and suggest its suitability as a promising scaffold for chondrocyte based cartilage repair.

Influence of age on rat bone-marrow mesenchymal stem cells potential

Mesenchymal stem cells promising role in cell-based therapies and tissue engineering appears to be limited due to a decline of their regenerative potential with increasing donor age. Six age groups from bone marrow mesenchymal stem cells of Wistar rats were studied (newborn, infant, young, pre-pubertal, pubertal and adult). Quantitative proteomic assay was performance by iTRAQ using an 8-plex iTRAQ labeling and the proteins differentially expressed were grouped in pluripotency, proliferative and metabolism processes. Proliferation makers, CD117 and Ki67 were measure by flow cytometry assay. Real time polymerase chain reaction analysis of pluripotency markers Rex1, Oct4, Sox2 and Nanog were done. Biological differentiation was realized using specific mediums for 14 days to induce osteogenesis, adipogenesis or chondrogenesis and immunostain analysis of differentiated cell resulting were done. Enzimoimmunoassay analysis of several enzymes as L-lactate dehydrogenase and glucose-6-phosphate isomerase were also done to validate iTRAQ data. Taking together these results indicate for the first time that mesenchymal stem cells have significant differences in their proliferative, pluripotency and metabolism profiles and those differences are age depending.

Microgel microenvironment primes adipose-derived stem cells towards an NP cells-like phenotype

Cell therapy of the degenerated intervertebral disc is limited by the lack of appropriate cell sources, thus new strategies for the differentiation of stem cells towards a nucleus pulposus (NP)-like phenotype need investigation. In the current study, it is hypothesized that spherical niche-like structures composed of type II collagen and hyaluronan (HA) mimic the NP microenvironment and promote the differentiation of adipose-derived stem cells (ADSCs) towards an NP-like phenotype. ADSCs are embedded in microgels of different concentrations of collagen II/HA. Cells' response to the different environments is studied by characterizing differences in cells' viability, morphology, and gene expression. After 21 days of culture, ADSCs maintain ± 80% viability in all the conditions tested. Moreover, microgels with higher concentration of collagen are stable and maintain cells in a rounder shape. In presence of differentiation media, cells are able to differentiate in all the conditions tested, but in a more pronounced manner in the microgel with a higher concentration of collagen. By tuning microgels' properties, it is possible to influence ADSCs' phenotype and ability to differentiate. Indeed, when cultured in high concentrations of collagen, ADSCs expresses high levels of collagen II, aggrecan, SOX9, and low levels of collagen I.

Establishment and characterization of immortalized gingival epithelial and fibroblastic cell lines for the development of organotypic cultures

In vitro studies using 3D co-cultures of gingival cells can resemble their in vivo counterparts much better than 2D models that typically only utilize monolayer cultures with short-living primary cells. However, the use of 3D gingival models is still limited through lack of appropriate cell lines. We aimed to establish immortalized cell line models of primary human gingival epithelium keratinocytes (HGEK) and gingival fibroblasts (GFB). Immortalized cell lines (HGEK-16 and GFB-16) were induced by E6 and E7 oncoproteins of human papillomavirus. In addition, 3D multilayered organotypic cultures were formed by embedding GFB-16 cells within a collagen (Col) matrix and seeding of HGEK-16 cells on the upper surfaces. Cell growth was analyzed in both immortalized cell lines and their parental primary cells. The expression levels of cell type-specific markers, i.e. cytokeratin (CK) 10, CK13, CK16, CK18, CK19 for HGEK-16 and Col I and Col II for GFB-16, were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). Expansion of the primary cultures was impeded at early passages, while the transformed immortalized cell lines could be expanded for more than 30 passages. In 3D cultures, immortalized HGEK formed a multilayer of epithelial cells. qRT-PCR showed that cell-specific marker expression in the 3D cultures was qualitatively and quantitatively closer to that in human gingival tissue than to monolayer cultures. These results indicate that immortalized gingival fibroblastic and epithelial cell lines can successfully form organotypic multilayered cultures and, therefore, may be useful tools for studying gingival tissue in vitro.

Hydrostatic pressure-driven three-dimensional cartilage induction using human adipose-derived stem cells and collagen gels

BACKGROUND

The chondrogenic potential of adipose-derived stem cells (ASCs) has been previously demonstrated, although several reports have indicated that ASCs produce less cartilage-specific matrix than bone marrow-derived mesenchymal stem cells. In this study, we intended to improve chondrogenic phenotypes of ASCs using hydrostatic pressure (HP), without utilizing any growth factors other than the transforming growth factor-β1.

METHODS

Human ASCs (CD13(+), 44(+), 90(+), 14(-), 31(-), 34(-)) were harvested and cultured. After three passages, the cells were suspended in 0.3% neutralized collagen type I solution and injected into semipermeable membrane tubes, from which 66 pouches were constructed. After a day of incubation, the 66 pouches were divided into three groups. Group HP1: Pouches were incubated for 1 week with treatment of cyclic HP at 0-0.5 MPa (4.93 atm), 0.5 Hz, with a medium replenishment rate of 0.1 mL/min at 37°C, 3% O2, and 5% CO2 in air using a bioprocessor. This was followed by 3 weeks with no HP and without pouches. Group HP2: Pouches were incubated for the first and third week (2 total weeks) with the same condition of Group HP1. No HP was applied in the second and fourth week. Group AP: Pouches with one end opened were incubated without HP. We evaluated the cell constructs histologically and immunohistochemically, as well as for specific gene expression.

RESULTS

Accumulation of the matrix in the HP1 and HP2 groups was much denser than AP groups, particularly after 2 weeks. Cell numbers in the HP groups increased gradually in the middle zone and peaked at 1 week after incubation, maintaining their numbers for the entire course on the surface layer of the construct. In the genomic study results, COL 2A1, COL 10A1, ACAN, SOX9, MMP3, and MMP13 were upregulated and COL 1A1, ITGB1, and PCNA were downregulated by HP. There were no significant differences between HP1 and HP2 gene expression.

CONCLUSION

It was suggested that HP is especially beneficial in the early stage of chondrogenesis of ASCs. Moreover, the expression profile of genes related to chondrocyte differentiation/proliferation was significantly enhanced by HP loading compared with the AP control.

Bone marrow derived stem cells in joint and bone diseases: a concise review

Stem cells have huge applications in the field of tissue engineering and regenerative medicine. Their use is currently not restricted to the life-threatening diseases but also extended to disorders involving the structural tissues, which may not jeopardize the patients' life, but certainly influence their quality of life. In fact, a particularly popular line of research is represented by the regeneration of bone and cartilage tissues to treat various orthopaedic disorders. Most of these pioneering research lines that aim to create new treatments for diseases that currently have limited therapies are still in the bench of the researchers. However, in recent years, several clinical trials have been started with satisfactory and encouraging results. This article aims to review the concept of stem cells and their characterization in terms of site of residence, differentiation potential and therapeutic prospective. In fact, while only the bone marrow was initially considered as a "reservoir" of this cell population, later, adipose tissue and muscle tissue have provided a considerable amount of cells available for multiple differentiation. In reality, recently, the so-called "stem cell niche" was identified as the perivascular space, recognizing these cells as almost ubiquitous. In the field of bone and joint diseases, their potential to differentiate into multiple cell lines makes their application ideally immediate through three main modalities: (1) cells selected by withdrawal from bone marrow, subsequent culture in the laboratory, and ultimately transplant at the site of injury; (2) bone marrow aspirate, concentrated and directly implanted into the injury site; (3) systemic mobilization of stem cells and other bone marrow precursors by the use of growth factors. The use of this cell population in joint and bone disease will be addressed and discussed, analysing both the clinical outcomes but also the basic research background, which has justified their use for the treatment of bone, cartilage and meniscus tissues.

Sirtuin-1 (SIRT1) is required for promoting chondrogenic differentiation of mesenchymal stem cells

Sirtuin-1 (SIRT1), NAD(+)-dependent deacetylase, has been linked to anabolic effects in cartilage, although the mechanisms of SIRT1 signaling during differentiation of mesenchymal stem cells (MSCs) to chondrocytes are poorly understood. Therefore, we investigated the role of SIRT1-mediated signaling during chondrogenic differentiation of MSCs in vitro. High density and alginate cultures of MSCs were treated with chondrogenic induction medium with/without the SIRT1 inhibitor nicotinamide, antisense oligonucleotides against SIRT1 (SIRT1-ASO), IL-1β, and/or resveratrol. Transient transfection of MSCs with SIRT1-antisense oligonucleotides, nicotinamide, and IL-1β inhibited chondrogenesis-induced down-regulation of cartilage-specific proteins, cartilage-specific transcription factor Sox9, and enhanced NF-κB-regulated gene products involved in the inflammatory and degradative processes in cartilage (MMP-9, COX-2, and caspase-3), and NF-κB phosphorylation, acetylation, and activation of IκBα kinase. In contrast, the SIRT1 activator resveratrol or BMS-345541 (inhibitor of IKK) inhibited IL-1β- and NAM-induced suppression of cartilage-specific proteins, Sox9, and up-regulation of NF-κB-regulated gene products. Moreover, SIRT1 was found to interact directly with NF-κB and resveratrol-suppressed IL-1β and NAM but not SIRT1-ASO-induced NF-κB phosphorylation, acetylation, and activation of IκBα kinase. Knockdown of SIRT1 by mRNA abolished the inhibitory effects of resveratrol on inflammatory and apoptotic signaling and Sox9 expression, suggesting the essential role of this enzyme. Finally, the modulatory effects of resveratrol were found to be mediated at least in part by the association between SIRT1 and Sox9. These results indicate for the first time that SIRT1 supports chondrogenic development of MSCs at least in part through inhibition/deacetylation of NF-κB and activation of Sox9.