Nanoparticle-Mediated TGF-ß Release from Microribbon-Based Hydrogels Accelerates Stem Cell-Based Cartilage Formation In Vivo.

Conventional nanoporous hydrogels often lead to slow cartilage deposition by MSCs in 3D due to physical constraints and requirement for degradation. Our group has recently reported macroporous gelatin microribbon (µRB) hydrogels, which substantially accelerate MSC-based cartilage formation in vitro compared to conventional gelatin hydrogels. To facilitate translating the use of µRB-based scaffolds for supporting stem cell-based cartilage regeneration in vivo, there remains a need to develop a customize-designed drug delivery system that can be incorporated into µRB-based scaffolds. Towards this goal, here we report polydopamine-coated mesoporous silica nanoparticles (MSNs) that can be stably incorporated within the macroporous µRB scaffolds, and allow tunable release of transforming growth factor (TGF)-ß3. We hypothesize that increasing concentration of polydopamine coating on MSNs will slow down TGF- ß3 release, and TGF-ß3 release from polydopamine-coated MSNs can enhance MSC-based cartilage formation in vitro and in vivo. We demonstrate that TGF-ß3 released from MSNs enhance MSC-based cartilage regeneration in vitro to levels comparable to freshly added TGF-ß3 in the medium, as shown by biochemical assays, mechanical testing, and histology. Furthermore, when implanted in vivo in a mouse subcutaneous model, only the group containing MSN-mediated TGF-ß3 release supported continuous cartilage formation, whereas control group without MSN showed loss of cartilage matrix and undesirable endochondral ossification. The modular design of MSN-mediated drug delivery can be customized for delivering multiple drugs with individually optimized release kinetics, and may be applicable to enhance regeneration of other tissue types.

Nanohybrid biodegradable scaffolds for TGF-ß3 release for the chondrogenic differentiation of human mesenchymal stem cells.

An ideal scaffold for bone tissue engineering should have chondroinductive, biodegradable, and biocompatible properties, as well as the ability to absorb and slowly release the biological molecules. In order to develop such a system to support bone tissue regeneration, in the present study, we developed a three-dimensional poly(L-lactic-co-glycolic acid) (PLGA)/Polycaprolactone (PCL) nanohybrid scaffold embedded with PLGA macroparticles (MPs) conjugated with TGF-ß3 for the growth and chondrogenic differentiation of human mesenchymal stem cells (hMSCs). First, a microfluidic device was used to fabricate porous PLGA MPs with the sizes ranging from 10 to 50 µm. Next, the PLGA MPs were loaded with TGF-ß3, mixed with PCL solution, and then electrospun to obtain PLGA-TGF-ß3 MPs/PCL nanohybrid scaffold. Our results demonstrated that PLGA MPs fabricated using a microfluidic-based approach exhibited enhanced conjugation of TGF-ß3 with over 80% loading efficiency and sustained release of TGF-ß3. Furthermore, the results of glycosaminoglycan (GAG) content measurement and Safranin O staining revealed that the PLGA-TGF-ß3 MPs and PLGA-TGF-ß3 MPs/PCL nanohybrid scaffold can promote the proliferation and chondrogenic differentiation of hMSCs in vitro. Therefore, the PLGA-TGF-ß3 MPs/PCL nanohybrid scaffold could pave the way for cartilage regeneration and have wide applications in regenerative medicine.

TGF-ß3 Loaded Electrospun Polycaprolacton Fibre Scaffolds for Rotator Cuff Tear Repair: An in Vivo Study in Rats.

Biological factors such as TGF-ß3 are possible supporters of the healing process in chronic rotator cuff tears. In the present study, electrospun chitosan coated polycaprolacton (CS-g-PCL) fibre scaffolds were loaded with TGF-ß3 and their effect on tendon healing was compared biomechanically and histologically to unloaded fibre scaffolds in a chronic tendon defect rat model. The biomechanical analysis revealed that tendon-bone constructs with unloaded scaffolds had significantly lower values for maximum force compared to native tendons. Tendon-bone constructs with TGF-ß3-loaded fibre scaffolds showed only slightly lower values. In histological evaluation minor differences could be observed. Both groups showed advanced fibre scaffold degradation driven partly by foreign body giant cell accumulation and high cellular numbers in the reconstructed area. Normal levels of neutrophils indicate that present mast cells mediated rather phagocytosis than inflammation. Fibrosis as sign of foreign body encapsulation and scar formation was only minorly present. In conclusion, TGF-ß3-loading of electrospun PCL fibre scaffolds resulted in more robust constructs without causing significant advantages on a cellular level. A deeper investigation with special focus on macrophages and foreign body giant cells interactions is one of the major foci in further investigations.

Proliferation, Migration, and ECM Formation Potential of Human Annulus Fibrosus Cells Is Independent of Degeneration Status.

OBJECTIVE: The objective was to evaluate the proliferating, migratory and extracellular matrix (ECM) forming potential of annulus fibrosus cells derived from early (edAFC) or advanced (adAFC) degenerative tissue and their usability as a possible cell source for regenerative approaches for AF closure. DESIGN: EdAFC (n = 5 Pfirrman score of 2-3) and adAFC (n = 5 Pfirrman score of 4-5) were isolated from tissue of patients undergoing spine stabilizing surgery. Cell migration on stimulation with human serum (HS), platelet-rich plasma (PRP), and transforming growth factor ß-3 (TGFB3) was assessed by migration assay and proliferation was assessed on stimulation with HS. Induction of ECM synthesis was evaluated by gene expression analysis of AF-related genes in three-dimensional scaffold cultures that have been stimulated with 5% PRP or 10 ng/mL TGFB3 and histologically by collagen type I, type II, alcian blue, and safranin-O staining. RESULTS: EdAFC and adAFC were significantly attracted by 10% HS and 5% PRP. Additionally, both cell groups proliferated under stimulation with HS. Stimulation with 10 ng/mL TGFB3 showed significant induction of gene expression of collagen type II and aggrecan, while 5% PRP decreased the expression of collagen type I. Both cell groups showed formation of AF-like ECM after stimulation with TGFB3, whereas stimulation with PRP did not. CONCLUSIONS: Our study demonstrated that AF cells retain their potential for proliferation, migration, and ECM formation independent of the degeneration status of the tissue. Proliferation, migration, and ECM synthesis of the endogenous AF cells can be supported by different supplements. Hence, endogenous AF cells might be a suitable cell source for a regenerative repair approaches.

Stress-relaxing double-network hydrogel for chondrogenic differentiation of stem cells.

The mechanical environment of extracellular matrix (ECM) plays an important role in adjusting the behaviors of cells. Natural ECM are highly viscoelastic materials with stress-relaxion behavior. Hydrogel is considered as a promising and attractive material for cell carrier, but they are typically elastic serving as synthetic ECM. Double-network (DN) hydrogel has an interpenetrating network of special structure combining the advantages of both rigid and ductile components, due to which the mechanical properties of the system can be very different from that of the single-network ones, and some special biological properties can be obtained. In this study, GG/PEGDA DN hydrogel was prepared by combining gellan gum (GG) with polyethylene glycol diacrylate (PEGDA), and then the influence of the two individual networks on the viscoelasticity of the system were investigated. Furthermore, the effects of viscoelasticity of GG/PEGDA DN hydrogel on the biological behavior of bone mesenchymal stem cells (BMSCs) were explored in vitro and in vivo. The results indicate that the spreading of BMSCs was closely related to the relaxation behavior of the hydrogels. GG/PEGDA DN hydrogel shows excellent mechanical and relaxation properties which provide a favorable physical environment for cell proliferation and spreading, and induce chondrogenic differentiation. Our study demonstrates that this DN hydrogel has bright prospects in the fields of cell carrier and cartilage tissue engineering.

Effect of dose and release rate of CTGF and TGFß3 on avascular meniscus healing.

Meniscus tears in the avascular region rarely functionally heal due to poor intrinsic healing capacity, frequently resulting in tear propagation, followed by meniscus deterioration. Recently, we have reported that time-controlled application of connective tissue growth factor (CTGF) and transforming tissue growth factor ß3 (TGFß3) significantly improved healing of avascular meniscus tears by inducing recruitment and step-wise fibrocartilaginous differentiation of mesenchymal stem/progenitor cells (MSCs). In this study, we investigated effects of the dose of CTGF and the release rate of TGFß3 on avascular meniscus healing in our existing explant model. Our hypothesis was that dose and release rate of CTGF and TGFß3 are contributing factors for functional outcome in avascular meniscus healing by stem cell recruitment. Low (100 ng/ml) and high (1,000 ng/ml) doses of CTGF as well as fast (0.46 ± 0.2 ng/day) and slow (0.29 ± 0.1 ng/day) release rates of TGFß3 were applied to our established meniscus explant model for meniscus tears in the inner-third avascular region. The release rate of TGFß3 was controlled by varying compositions of poly(lactic-co-glycolic acids) (PLGA) microspheres. The meniscus explants were then cultured for 8 weeks on top of mesenchymal stem/progenitor cells (MSCs). Among the tested combinations, we found that a high CTGF dose and slow TGFß3 release are most effective for integrated healing of avascular meniscus, demonstrating improvements in alignment of collagen fibers, fibrocartilaginous matrix elaboration and mechanical properties. This study may represent an important step toward the development of a regenerative therapy to improve healing of avascular meniscus tears by stem cell recruitment. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1555-1562, 2019.

Layer-by-layer deposition of chitosan nanoparticles as drug-release coatings for PCL nanofibers.

Nanogels were prepared by ionotropic gelation of chitosan (CS) with tripolyphosphate (TPP). The use of such nanogels to prepare coatings by layer-by-layer deposition (LbL) was studied. The nanogels were characterized in terms of particle size, zeta-potential and stability. Nanogel suspensions were used to build polyelectrolyte multilayers on silicon wafers and on PCL fiber mats by LbL-deposition. Three different polysaccharides were used as polyanions, namely chondroitin sulfate, alginate and hyaluronic acid. The ellipsometric thickness was demonstrated to depend significantly on the type of polyanion. XPS analysis with depth profiling further substantiated the differences in the chemical composition of the films with the different polyanions. Furthermore, XPS data clearly indicated a strong penetration of the polyanions into the CS-TPP layer, resulting in a complete exchange and release of the TPP ions. The LbL-deposition also was studied with PCL fiber mats, which were modified with a chitosan-PCL-graft polymer and alginate. The possibility to create graded coatings on the fiber mats was shown employing fluorescently labelled CS-TPP nanoparticles. The potential of the coatings as drug delivery system for therapeutic proteins was exemplified with the release of Transforming Growth Factor ß3 (TGF-ß3). The CS-TPP nanogels were shown to encapsulate and release therapeutic proteins. In combination with the layer-by-layer deposition they will allow the creation of PCL fiber mat implants having with drug gradients for applications at tissue transitions.

Peripheral Blood Mesenchymal Stem Cells Combined with Modified Demineralized Bone Matrix Promote Pig Cartilage Defect Repair.

OBJECTIVE: To investigate the mobilization of peripheral blood mesenchymal stem cells (PBMSCs) and whether a combination of PBMSCs and modified demineralized bone matrix (DBM) promoted the repair of cartilage lesions in a pig model. METHODS: Pig PBMSCs were mobilized by the combined administration of granulocyte colony-stimulating factor (G-CSF) and the CXCR4 antagonist AMD3100. Colony formation was detected by the fibroblast colony-forming unit (CFU-F) count and the percentage of the CD45-CD90+ cell population by flow cytometry. The mobilized cells were identified as MSCs by their morphological characteristics, surface markers, and differentiation potentials. The composite scaffolds carrying BMP-2 and TGF-ß3 chitosan sustained-release microspheres/DBM were prepared by emulsion cross-linking and the Urist method, and scanning electron microscopy (SEM) observation was performed. The model of pig cartilage defect was prepared, and gross observation, histological examination, immunohistochemistry, and O'Driscoll scoring were performed 4, 8, and 12 weeks postoperation. RESULTS: After mobilization, the number of CFU-Fs in the peripheral blood in the experimental group (G-CSF + AMD3100) was significantly increased compared with the control group (p < 0.05). The proportion and total number of CD45-CD90+ cells were increased (p < 0.05). The mobilized stem cells had MSC characteristics. SEM of the new tissue-engineered cartilage showed that PBMSCs were evenly grown on the surface of the scaffold and microsphere morphology had no obvious change. Gross observation, histological examination, immunohistochemistry, and O'Driscoll score were better in the experimental group than in the other groups (p < 0.05). CONCLUSION: G-CSF + AMD3100 is an effective mobilization agent for PBMSCs. The new tissue-engineering cartilage constructed by two-factor sustained-release microspheres/DBM composite PBMSCs effected good repair of the cartilage defect in pigs.

Silk fibroin/cartilage extracellular matrix scaffolds with sequential delivery of TGF-ß3 for chondrogenic differentiation of adipose-derived stem cells.

A 3-D scaffold that simulates the microenvironment in vivo for regenerating cartilage is ideal. In this study, we combined silk fibroin and decellularized cartilage extracellular matrix by temperature gradient-guided thermal-induced phase separation to produce composite scaffolds (S/D). Resulting scaffolds had remarkable mechanical properties and biomimeticstructure, for a suitable substrate for attachment and proliferation of adipose-derived stem cells (ADSCs). Moreover, transforming growth factor ß3 (TGF-ß3) loaded on scaffolds showed a controlled release profile and enhanced the chondrogenic differentiation of ADSCs during the 28-day culture. The S/D scaffold itself can provide a sustained release system without the introduction of other controlled release media, which has potential for commercial and clinical applications. The results of toluidine blue, Safranin O, and immunohistochemical staining and analysis of collagen II expression showed maintenance of a chondrogenic phenotype in all scaffolds after 28-day culture. The most obvious phenomenon was with the addition of TGF-ß3. S/D composite scaffolds with sequential delivery of TGF-ß3 may mimic the regenerative microenvironment to enhance the chondrogenic differentiation of ADSCs in vitro.

Analysis of sphingolipids in human corneal fibroblasts from normal and keratoconus patients.

The pathophysiology of human keratoconus (KC), a bilateral progressive corneal disease leading to protrusion of the cornea, stromal thinning, and scarring, is not well-understood. In this study, we investigated a novel sphingolipid (SPL) signaling pathway through which KC may be regulated. Using human corneal fibroblasts (HCFs) and human KC cells (HKCs), we examined the SPL pathway modulation. Both cell types were stimulated by the three transforming growth factor (TGF)-ß isoforms: TGF-ß1 (T1), TGF-ß2 (T2), and TGF-ß3 (T3). All samples were analyzed using lipidomics and real-time PCR. Our data showed that HKCs have increased levels of signaling SPLs, ceramide (Cer), and sphingosine 1-phosphate (S1P). Treatment with T1 reversed the increase in Cer in HKCs and treatment with T3 reversed the increase in S1P. S1P3 receptor mRNA levels were also significantly upregulated in HKCs, but were reduced to normal levels following T3 treatment. Furthermore, stimulation with Cer and S1P led to significant upregulation of fibrotic markers in HCFs, but not in HKCs. Additionally, stimulation with a Cer synthesis inhibitor (FTY720) led to significant downregulation of specific fibrotic markers in HKCs (TGF-ß1, collagen type III, and α smooth muscle actin) without an effect on healthy HCFs, suggesting a causative role of Cer and S1P in fibrogenesis. Overall, this study suggests an association of the SPL signaling pathway in KC disease and its relation with the TGF-ß pathway.

Dual delivery of growth factors with coacervate-coated poly(lactic-co-glycolic acid) nanofiber improves neovascularization in a mouse skin flap model.

Random skin flaps are commonly used in plastic and reconstructive surgery for patients suffering from severe or large scale wounds or in facial reconstruction. However, skin flaps are sometimes susceptible to partial or complete necrosis at the distal parts of the flaps due to insufficient blood perfusion in the defected area. In order to improve neovascularization in skin flaps, we developed an exogenous growth factor (GF) delivery platform comprised of coacervate-coated poly(lactic-co-glycolic acid) (PLGA) nanofibers. We used a coacervate that is a self-assembled complex of poly(ethylene argininyl aspartate diglyceride) (PEAD) polycation, heparin, and cargo GFs (i.e., vascular endothelial growth factor (VEGF) and/or transforming growth factor beta 3 (TGF-ß3)). The coacervate was coated onto a nanofibrous PLGA membrane for co-administration of dual GFs. In vitro proliferation of human dermal fibroblasts and endothelial tube formation using human umbilical vein endothelial cells indicated an enhanced bioactivity of released GFs when both VEGF and TGF-ß3 were incorporated into coacervate-coated PLGA nanofibers (Coa-Dual NFs). Moreover, an in vivo study using a mouse skin flap model demonstrated that implantation of Coa-Dual NF reduced necrosis and enhanced blood perfusion in skin flap areas after 10 days, as compared to any single GF-loaded coacervate/PLGA fiber (Coa-Single NF) along with direct administration of the other GF onto the defect site. Moreover, Coa-Dual NFs exhibited a well-composed skin appendage and a significantly higher number of blood vessels. Based upon these results, we conclude that Coa-Dual NFs may stimulate cellular activity by enhancing the bioactivity of the released GF, leading to a synergetic effect of dual GFs for reducing necrosis in the random skin flaps. Therefore, Coa-Dual NFs could be a valuable drug delivery platform for a variety of potential clinical applications for skin tissue regeneration applications.

Chondrogenically primed tonsil-derived mesenchymal stem cells encapsulated in riboflavin-induced photocrosslinking collagen-hyaluronic acid hydrogel for meniscus tissue repairs.

Current meniscus tissue repairing strategies involve partial or total meniscectomy, followed by allograft transplantation or synthetic material implantation. However, allografts and synthetic implants have major drawbacks such as the limited supply of grafts and lack of integration into host tissue, respectively. In this study, we investigated the effects of conditioned medium (CM) from meniscal fibrochondrocytes and TGF-ß3 on tonsil-derived mesenchymal stem cells (T-MSCs) for meniscus tissue engineering. CM-expanded T-MSCs were encapsulated in riboflavin-induced photocrosslinked collagen-hyaluronic acid (COL-RF-HA) hydrogels and cultured in chondrogenic medium containing TGF-ß3. In vitro results indicate that CM-expanded cells followed by TGF-ß3 exposure stimulated the expression of fibrocartilage-related genes (COL2, SOX9, ACAN, COL1) and production of extracellular matrix components. Histological assessment of in vitro and subcutaneously implanted in vivo constructs demonstrated that CM-expanded cells followed by TGF-ß3 exposure resulted in highest cell proliferation, GAG accumulation, and collagen deposition. Furthermore, when implanted into meniscus defect model, CM treatment amplified the potential of TGF-ß3 and induced complete regeneration. STATEMENT OF SIGNIFICANCE: Conditioned medium derived from chondrocytes have been reported to effectively prime mesenchymal stem cells toward chondrogenic lineage. Type I collagen is the main component of meniscus extracellular matrix and hyaluronic acid is known to promote meniscus regeneration. In this manuscript, we investigated the effects of conditioned medium (CM) and transforming growth factor-ß3 (TGF-ß3) on tonsil-derived mesenchymal stem cells (T-MSCs) encapsulated in riboflavin-induced photocrosslinked collagen-hyaluronic acid (COL-RF-HA) hydrogel. We employed a novel source of conditioned medium, derived from meniscal fibrochondrocytes. Our in vitro and in vivo results collectively illustrate that CM-expanded cells followed by TGF-ß3 exposure have the best potential for meniscus regeneration. This manuscript highlights a novel stem cell commitment strategy combined with biomaterials designs for meniscus regeneration.

New scaffolds encapsulating TGF-ß3/BMP-7 combinations driving strong chondrogenic differentiation.

The regeneration of articular cartilage remains an unresolved question despite the current access to a variety of tissue scaffolds activated with growth factors relevant to this application. Further advances might result from combining more than one of these factors; here, we propose a scaffold composition optimized for the dual delivery of BMP-7 and TGF-ß3, two proteins with described chondrogenic activity. First, we tested in a mesenchymal stem cell micromass culture with TGF-ß3 whether the exposure to microspheres loaded with BMP-7 would improve cartilage formation. Histology and qRT-PCR data confirmed that the sustained release of BMP-7 cooperates with TGF-ß3 towards chondrogenic differentiation. Then, we optimized a scaffold prototype for tissue culture and dual encapsulation of BMP-7 and TGF-ß3. The scaffolds were prepared from poly(lactic-co-glycolic acid), and BMP-7/TGF-ß3 were loaded as nanocomplexes with heparin and Tetronic 1107. The scaffolds showed the sustained release of both proteins over four weeks, with minimal burst effect. We finally cultured human mesenchymal stem cells on these scaffolds, in the absence of exogenous chondrogenic factor supplementation. The cells cultured on the scaffolds loaded with BMP-7 and TGF-ß3 showed clear signs of cartilage formation macroscopically and histologically. RT-PCR studies confirmed a clear upregulation of cartilage markers SOX9 and Aggrecan. In summary, scaffolds encapsulating BMP-7 and TGF-ß3 can efficiently deliver a cooperative growth factor combination that drives efficient cartilage formation in human mesenchymal stem cell cultures. These results open attractive perspectives towards in vivo translation of this technology in cartilage regeneration experiments.

A Closed Chondromimetic Environment within Magnetic-Responsive Liquified Capsules Encapsulating Stem Cells and Collagen II/TGF-ß3 Microparticles.

TGF-ß3 is enzymatically immobilized by transglutaminase-2 action to poly(l-lactic acid) microparticles coated with collagen II. Microparticles are then encapsulated with stem cells inside liquified spherical compartments enfolded with a permselective shell through layer-by-layer adsorption. Magnetic nanoparticles are electrostatically bound to the multilayered shell, conferring magnetic-response ability. The goal of this study is to engineer a closed environment inside which encapsulated stem cells would undergo a self-regulated chondrogenesis. To test this hypothesis, capsules are cultured in chondrogenic differentiation medium without TGF-ß3. Their biological outcome is compared with capsules encapsulating microparticles without TGF-ß3 immobilization and cultured in normal chondrogenic differentiation medium containing soluble TGF-ß3. Glycosaminoglycans quantification demosntrates that similar chondrogenesis levels are achieved. Moreover, collagen fibrils resembling the native extracellular matrix of cartilage can be observed. Importantly, the genetic evaluation of characteristic cartilage markers confirms the successful chondrogenesis, while hypertrophic markers are downregulated. In summary, the engineered capsules are able to provide a suitable and stable chondrogenesis environment for stem cells without the need of TGF-ß3 supplementation. This kind of self-regulated capsules with softness, robustness, and magnetic responsive characteristics is expected to provide injectability and in situ fixation, which is of great advantage for minimal invasive strategies to regenerate cartilage.

PLGA-based microcarriers induce mesenchymal stem cell chondrogenesis and stimulate cartilage repair in osteoarthritis.

In the present study, we aimed at evaluating the ability of novel PLGA-P188-PLGA-based microspheres to induce the differentiation of mesenchymal stem/stromal cells (MSC) into chondrocytes. To this aim, we tested microspheres releasing TGFß3 (PAM-T) in vitro and in situ, in a pathological osteoarthritic (OA) environment. We first evaluated the chondrogenic differentiation of human MSCs seeded onto PAM-T in vitro and confirmed the up-regulation of chondrogenic markers while the secretome of the cells was not changed by the 3D environment. We then injected human MSC seeded onto PAM-T in the knee joints of mice with collagenase-induced OA. After 6 weeks, histological analysis revealed that formation of a cartilage-like tissue occurred at the vicinity of PAM-T that was not observed when MSCs were seeded onto PAM. We also noticed that the endogenous articular cartilage was less degraded. The extent of cartilage protection was further analysed by confocal laser microscopy. When MSCs seeded onto PAM-T were injected early after OA induction, protection of cartilage against degradation was evidenced and this effect was associated to a higher survival of MSCs in presence of TGFß3. This study points to the interest of using MSCs seeded onto PAM for cartilage repair and stimulation of endogenous cartilage regeneration.

Survivin-TGFB3-TIMP1 Gene Therapy Via Lentivirus Vector Slows the Course of Intervertebral Disc Degeneration in an In Vivo Rabbit Model.

STUDY DESIGN: The ability of lentivirus vector (LV) survivin-transforming growth factor beta 3 (TGFB3)-tissue inhibitor of metalloproteinases 1 (TIMP1) on slowing disc degeneration was evaluated by an animal experiment. OBJECTIVE: The aim of the study was to investigate the effect of LV survivin-TGFB3-TIMP1 on slowing disc degeneration in an in vivo rabbit model. SUMMARY OF BACKGROUND DATA: Cell apoptosis, increase of catabolic activity, and decrease of anabolic activity were the mechanisms of disc degeneration. Meanwhile, survivin, TGFB3, and TIMP1 can influence above process, respectively. However, there were no researches conducted to evaluate the effect of an LV containing all three proteins (referred to as LV-survivin-TGFB3-TIMP1) on slowing disc degeneration in vivo. METHODS: Twenty skeletally mature female New Zealand White rabbits were randomly divided into four groups: nonpunctured sham surgical group (group A, n = 5), punctured blank control group (group B, n = 5), punctured empty vector control group (group C, n = 5), and the treatment group (group D, n = 5). Computed tomography-guided puncture was performed at the L3-L4 and L4-L5 discs, in accordance with a previously validated rabbit annulotomy model for intervertebral disc degeneration. After 3 weeks, LV-carrying survivin, TGFB3, and TIMP1 were injected into the nucleus pulposus. Serial magnetic resonance imaging studies at 0, 3, and 12 weeks were performed. The rabbits were sacrificed at 12 weeks, and the histology, immunofluorescence, quantitative real-time polymerase chain reaction, Western blot, and caspase-3 activity was used for evaluation. RESULTS: Magnetic resonance imaging, histology, gene expression, protein content, and apoptosis analyses of group A showed no disc degeneration. Groups B and C showed disc degeneration, which increased over time, and no significant difference was observed between the two groups (P > 0.05). In group D, there was less disc degeneration compared to the punctured control groups and the difference was statistically significant (P < 0.05). CONCLUSION: The injection of LV-carrying survivin-TGFB3-TIMP1 into punctured rabbit intervertebral discs helps delay degenerative disc changes. Although data from animal models should be extrapolated to the human condition with caution, this study shows promise for gene therapy to decelerate disc degeneration. LEVEL OF EVIDENCE: N/A.

Tissue segregation restores the induction of bone formation by the mammalian transforming growth factor-ß(3) in calvarial defects of the non-human primate Papio ursinus.

A diffusion molecular hypothesis from the dura and/or the leptomeninges below that would control the induction of calvarial membranous bone formation by the recombinant human transforming growth factor-ß3 (hTGF-ß3) was investigated. Coral-derived calcium carbonate-based macroporous constructs (25 mm diameter; 3.5/4 mm thickness) with limited hydrothermal conversion to hydroxyapatite (7% HA/CC) were inserted into forty calvarial defects created in 10 adult Chacma baboons Papio ursinus. In 20 defects, an impermeable nylon foil membrane (SupraFOIL(®)) was inserted between the cut endocranial bone and the underlying dura mater. Twenty of the macroporous constructs were preloaded with hTGF-ß3 (125 µg in 1000 µl 20 mM sodium succinate, 4% mannitol pH4.0), 10 of which were implanted into defects segregated by the SupraFOIL(®) membrane, and 10 into non-segregated defects. Tissues were harvested on day 90, processed for decalcified and undecalcified histology and quantitative real-time polymerase chain reaction (qRT-PCR). Segregated untreated macroporous specimens showed a reduction of bone formation across the macroporous spaces compared to non-segregated constructs. qRT-PCR of segregated untreated specimens showed down regulation of osteogenic protein-1 (OP-1), osteocalcin (OC), bone morphogenetic protein-2 (BMP-2), RUNX-2 and inhibitor of DNA binding-2 and -3 (ID2,ID3) and up regulation of TGF-ß3, a molecular signalling pathway inhibiting the induction of membranous bone formation. Non-segregated hTGF-ß3/treated constructs also showed non-osteogenic expression profiles when compared to non-segregated untreated specimens. Segregated hTGF-ß3/treated 7% HA/CC constructs showed significantly greater induction of bone formation across the macroporous spaces and, compared to non-segregated hTGF-ß3/treated constructs, showed up regulation of OP-1, OC, BMP-2, RUNX-2, ID2 and ID3. Similar up-regulated expression profiles were seen for untreated non-segregated constructs. TGF-ß signalling via ID genes creates permissive or refractory micro-environments that regulate the induction of calvarial bone formation which is controlled by the exogenous hTGF-ß3 upon segregation of the calvarial defects. The dura is the common regulator of the induction of calvarial bone formation modulated by the presence or absence of the SupraFOIL(®) membrane with or without hTGF-ß3.

Scaffolds for Controlled Release of Cartilage Growth Factors.

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.

Nanostructured Capsules for Cartilage Tissue Engineering.

Polymeric multilayered capsules (PMCs) have found great applicability in bioencapsulation, an evolving branch of tissue engineering and regenerative medicine. Here, we describe the production of hierarchical PMCs composed by an external multilayered membrane by layer-by-layer assembly of poly(L-lysine), alginate, and chitosan. The core of the PMCs is liquified and encapsulates human adipose stem cells and surface-functionalized collagen II-TGF-ß3 poly(L-lactic acid) microparticles for cartilage tissue engineering.

[CONDITIONS OF SYNOVIAL MESENCHYMAL STEM CELLS DIFFERENTIATING INTO FIBROCARTILAGE CELLS].

OBJECTIVE: To explore the conditions of synovial derived mesenchymal stem cells (SMSCs) differentiating into the fibrocartilage cells by using the orthogonal experiment. METHODS: The synovium was harvested from 5 adult New Zealand white rabbits, and SMSCs were separated by adherence method. The flow cytometry and multi-directional differentiation method were used to identify the SMSCs. The conditions were found from the preliminary experiment and literature review. The missing test was carried out to screen the conditions and then 12 conditions were used for the orthogonal experiment, including transforming growth factor ß1 (TGF-ß1), bone morphogenic protein 2 (BMP-2), dexamethasone (DEX), proline, ascorbic acid (ASA), pyruvic acid, insulin + transferrin + selenious acid pre-mixed solution (ITS), bovin serum albumin (BSA), basic fibroblast growth factor (bFGF), intermittent hydraulic pressure (IHP), bone morphogenic protein 7 (BMP-7), and insulin-like growth factor (IGF). The L60 (212) orthogonal experiment was designed using the SPSS 18.0 with 2 level conditions and the cells were induced to differentiate on the small intestinal submucosa (SIS)-3D scaffold. The CD151+/CD44+ cells were detected with the flow cytometry and then the differentiation rate was recorded. The immumohistochemical staining, cellular morphology, toluidine blue staining, and semi-quantitative RT-PCR examination for the gene expressions of sex determining region Y (SRY)-box 9 gene (Sox9), aggrecan gene (AGN), collagen type I gene (Col I), collagen type II gene (Col II), collagen type IX gene (Col IX) were used for result confirmation. The differentiation rate was calculated as the product of CD151/CD44+ cells and cells with Col I high expression. The grow curve was detected with the DNA abundance using the PicoGreen Assay. The visual observation and the variances analysis among the variable were used to evaluate the result of the orthogonal experiment, 1 level interaction was considered. The q-test and the least significant difference (LDS) were used for the variance analysis with a type III calibration model. The test criteria (a) was 0.05. RESULTS: The cells were certified as SMSCs, the double-time of the cells was 28 hours. During the differentiation into the fibrocartilage, the volume of the SIS-3D scaffold enlarged double every 5 days. The scaffolds were positively stained by toluidine blue at 14 days. The visual observation showed that high levels of TGF-ß1 and BMP-7 were optimum for the differentiation, and BMP-7 showed the interaction with BMP-2. The conditions of DEX, ASA, ITS, transferrin, bFGF showed decreasing promotional function by degrees, and the model showed the perfect relevance. P value was 0.000 according to the variance analysis. The intercept analysis showed different independent variables brought about variant contribution; the TGF-ß1, ASA, bFGF, IGF, and BMP-7 were more remarkable, which were similar to the visual observation. CONCLUSION: In the process of the SMSCs differentiation into the fibrocartilage, the concentrations of TGF-ß1, ASA, bFGF, and IGF reasonably can improve the conversion rate of the fibrocartilage cells. The accurate conditions of the reaulatory factor should be explored further.