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Sample records for osteochondral tissue grafts

  1. Osteochondral tissue engineering.

    PubMed

    Martin, Ivan; Miot, Sylvie; Barbero, Andrea; Jakob, Marcel; Wendt, David

    2007-01-01

    Osteochondral defects (i.e., defects which affect both the articular cartilage and underlying subchondral bone) are often associated with mechanical instability of the joint, and therefore with the risk of inducing osteoarthritic degenerative changes. Current surgical limits in the treatment of complex joint lesions could be overcome by grafting osteochondral composite tissues, engineered by combining the patient's own cells with three-dimensional (3D) porous biomaterials of pre-defined size and shape. Various strategies have been reported for the engineering of osteochondral composites, which result from the use of one or more cell types cultured into single-component or composite scaffolds in a broad spectrum of compositions and biomechanical properties. The variety of concepts and models proposed by different groups for the generation of osteochondral grafts reflects that understanding of the requirements to restore a normal joint function is still poor. In order to introduce the use of engineered osteochondral composites in the routine clinical practice, it will be necessary to comprehensively address a number of critical issues, including those related to the size and shape of the graft to be generated, the cell type(s) and properties of the scaffold(s) to be used, the potential physical conditioning to be applied, the degree of functionality required, and the strategy for a cost-effective manufacturing. The progress made in material science, cell biology, mechanobiology and bioreactor technology will be key to support advances in this challenging field. PMID:16730354

  2. Fabrication of tissue engineered osteochondral grafts for restoring the articular surface of diarthrodial joints

    PubMed Central

    Roach, Brendan L.; Hung, Clark T.; Cook, James L.; Ateshian, Gerard A.; Tan, Andrea R.

    2015-01-01

    Osteochondral allograft implantation is an effective cartilage restoration technique for large defects (>10 cm2), though the demand far exceeds the supply of available quality donor tissue. Large bilayered engineered cartilage tissue constructs with accurate anatomical features (i.e. contours, thickness, architecture) could be beneficial in replacing damaged tissue. When creating these osteochondral constructs, however, it is pertinent to maintain biofidelity to restore functionality. Here, we describe a step-by-step framework for the fabrication of a large osteochondral construct with correct anatomical architecture and topology through a combination of high-resolution imaging, rapid prototyping, impression molding, and injection molding. PMID:25794950

  3. Fabrication of tissue engineered osteochondral grafts for restoring the articular surface of diarthrodial joints.

    PubMed

    Roach, Brendan L; Hung, Clark T; Cook, James L; Ateshian, Gerard A; Tan, Andrea R

    2015-08-01

    Osteochondral allograft implantation is an effective cartilage restoration technique for large defects (>10 cm(2)), though the demand far exceeds the supply of available quality donor tissue. Large bilayered engineered cartilage tissue constructs with accurate anatomical features (i.e. contours, thickness, architecture) could be beneficial in replacing damaged tissue. When creating these osteochondral constructs, however, it is pertinent to maintain biofidelity to restore functionality. Here, we describe a step-by-step framework for the fabrication of a large osteochondral construct with correct anatomical architecture and topology through a combination of high-resolution imaging, rapid prototyping, impression molding, and injection molding. PMID:25794950

  4. Osteochondral Tissue Cell Viability Is Affected by Total Impulse during Impaction Grafting

    PubMed Central

    Balash, Paul; Kang, Richard W.; Schwenke, Thorsten; Cole, Brian J.; Wimmer, Markus A.

    2010-01-01

    Objective: Osteochondral graft transplantation has garnered significant attention because of its ability to replace the lesion with true hyaline cartilage. However, surgical impaction of the graft to anchor it into the defect site can be traumatic and lead to cell death and cartilage degeneration. This study aimed to test the hypothesis that increasing impulse magnitude during impaction of osteochondral plugs has a direct effect on loss of cell viability. Design: In this controlled laboratory study, the impaction force was kept constant while the impulse was varied. Ninety-six osteochondral plugs were extracted from the trochlea of bovine stifle joints and were randomly assigned into 3 experimental and 1 (nonimpacted) control group. The transferred impulse of the experimental groups reflected the median and the lower and upper quartiles of preceding clinical measurements. Data were obtained at day 0, day 4, and day 8; at each point, cell viability was assessed using the Live/Dead staining kit and histological assessments were performed to visualize matrix structural changes. Results: After impaction, cartilage samples stayed intact and did not show any histological signs of matrix disruption. As expected, higher impulse magnitudes introduced more cell death; however, this relationship was lost at day 8 after impaction. Conclusion: Impulse magnitude has a direct effect on cell viability of the graft. Because impulse magnitude is mostly governed by the press-fit characteristics of the recipient site, this study aids in the definition of optimal insertion conditions for osteochondral grafts. PMID:26069558

  5. Chondrocytes within osteochondral grafts are more resistant than osteoblasts to tissue culture at 37°C.

    PubMed

    Bastian, Johannes D; Egli, Rainer J; Ganz, Reinhold; Hofstetter, Willy; Leunig, Michael

    2011-01-01

    It is proposed that an ideal osteochondral allograft for cartilage repair consists of a devitalized bone but functional cartilage. The different modes of nutrient supply in vivo for bone (vascular support) and cartilage (diffusion) suggest that a modulation of storage conditions could differentially affect the respective cells, resulting in the proposed allograft. For this purpose, osteochondral tissues from porcine humeral heads were either cultured at 37°C for up to 24 hr or stored at 4°C for 24 hr, the temperature at which osteochondral allografts are routinely stored. Functionality of the cells was assessed by in situ hybridization for transcripts encoding collagen types I and II. At 37°C, a time-dependent significant reduction of the bone surface covered with functional cells was observed with only 5% ± 5% coverage left at 24 hr compared with 41% ± 10% at 0 hr. Similarly, cartilage area containing functional cells was significantly reduced from 84% ± 7% at 0 hr to 70% ± 3% after 24 hr. After 24 hr at 4°C, a significantly reduced amount of functional cells covering bone surfaces was observed (27% ± 5%) but not of cells within the cartilage (79% ± 8%). In the applied experimental setup, bone cells were more affected by tissue culture at 37°C than cartilage cells. Even though chondrocytes appear to be more sensitive to 37°C than to 4°C, the substantially reduced amount of functional bone cells at 37°C warrants further investigation of whether a preincubation of osteochondral allografts at 37°C--prior to regular storage at 4°C--might result in an optimized osteochondral allograft with devitalized bone but viable cartilage. PMID:21275527

  6. Review of the biomechanics and biotribology of osteochondral grafts used for surgical interventions in the knee

    PubMed Central

    Bowland, Philippa; Ingham, E; Jennings, Louise; Fisher, John

    2015-01-01

    A review of research undertaken to evaluate the biomechanical stability and biotribological behaviour of osteochondral grafts in the knee joint and a brief discussion of areas requiring further improvement in future studies are presented. The review takes into consideration osteochondral autografts, allografts, tissue engineered constructs and synthetic and biological scaffolds. PMID:26614801

  7. MR imaging of osteochondral grafts and autologous chondrocyte implantation

    PubMed Central

    Millington, S. A.; Szomolanyi, P.; Marlovits, S.

    2006-01-01

    Surgical articular cartilage repair therapies for cartilage defects such as osteochondral autograft transfer, autologous chondrocyte implantation (ACI) or matrix associated autologous chondrocyte transplantation (MACT) are becoming more common. MRI has become the method of choice for non-invasive follow-up of patients after cartilage repair surgery. It should be performed with cartilage sensitive sequences, including fat-suppressed proton density-weighted T2 fast spin-echo (PD/T2-FSE) and three-dimensional gradient-echo (3D GRE) sequences, which provide good signal-to-noise and contrast-to-noise ratios. A thorough magnetic resonance (MR)-based assessment of cartilage repair tissue includes evaluations of defect filling, the surface and structure of repair tissue, the signal intensity of repair tissue and the subchondral bone status. Furthermore, in osteochondral autografts surface congruity, osseous incorporation and the donor site should be assessed. High spatial resolution is mandatory and can be achieved either by using a surface coil with a 1.5-T scanner or with a knee coil at 3 T; it is particularly important for assessing graft morphology and integration. Moreover, MR imaging facilitates assessment of complications including periosteal hypertrophy, delamination, adhesions, surface incongruence and reactive changes such as effusions and synovitis. Ongoing developments include isotropic 3D sequences, for improved morphological analysis, and in vivo biochemical imaging such as dGEMRIC, T2 mapping and diffusion-weighted imaging, which make functional analysis of cartilage possible. PMID:16802126

  8. Fixation with autogenous osteochondral grafts for the treatment of osteochondritis dissecans (stages III and IV)

    PubMed Central

    Balacó, Inês

    2007-01-01

    This paper presents a clinical and functional assessment of the cases of osteochondritis dissecans (OCD) treated with small mosaicplasty type osteochondral grafts. Between 1999 and 2004, we operated on 12 knees with OCD stages III and IV. They were assessed using the International Cartilage Research Society (ICRS) scale, the Visual Analogue Scale (VAS) scale, X-ray and magnetic resonance imaging (MRI). The study was carried out using a clinical series, was retrospective and had a level of evidence of 4. Before surgery, all patients were in classes III and IV on the ICRS scale (four in class III and eight in class IV). At the time of surgery, the patient age was 27.5 ± 7.9 years, with male predominance (75%). Eleven of the cases were assessed as classes I and II on the ICRS scale (seven in class I and four in class II), with one patient in class IV. X-ray assessment was less favourable, revealing alterations in the articular space in 75% of cases. The results show that this technique enables the biological fixation of fragments and, functionally, the clinical results obtained were very good. The osteochondral grafts avoid the implantation of foreign material and make use of bone fragments of the same rigidity as the OCD fragment. We conclude that the technique described is an excellent alternative to the techniques normally used for the fixation of stage III and IV OCD. PMID:18038231

  9. Recent progress in interfacial tissue engineering approaches for osteochondral defects.

    PubMed

    Castro, Nathan J; Hacking, S Adam; Zhang, Lijie Grace

    2012-08-01

    This review provides a brief synopsis of the anatomy and physiology of the osteochondral interface, scaffold-based and non-scaffold based approaches for engineering both tissues independently as well as recent developments in the manufacture of gradient constructs. Novel manufacturing techniques and nanotechnology will be discussed with potential application in osteochondral interfacial tissue engineering. PMID:22677924

  10. Technique: Osteochondral Grafting of Capitate Chondrosis in PRC

    PubMed Central

    Tang, Peter; Imbriglia, Joseph E.

    2013-01-01

    Background Proximal row carpectomy (PRC) is a useful treatment option for wrist arthritis, but the operation is contraindicated when there is arthritis of the capitate head. We describe a technique that involves resurfacing of a capitate that has focal chondrosis, using an osteochondral graft harvested from the resected carpal bones. Materials and Methods PRC patients who had a focal area of capitate chondrosis underwent osteochondral grafting of the capitate. Pre- and postoperative pain level, employment status, motion, grip strength, and Modified Mayo Wrist Scores (MMWS) were assessed. Postoperative Disability of the Arm, Shoulder, and Hand (DASH) scores were also calculated. Description of Technique The articular surface of the capitate is assessed for need for grafting. The proximal row is resected with the lunate removed intact. The arthritic area is prepared. The graft is taken from the lunate and placed in the prepared site of the capitate. Results Eight patients (average age of 53 years) were followed for 18 months. Pain: Preoperatively, moderate to severe in 7 patients; postoperatively, mild to no pain in 7 patients. Motion: Preoperative, 84° (74% of the contralateral side); postoperative 75° (66%). Grip Strength: Preoperative, 29 kg (62%); postoperative, 34 kg (71%). Mayo Wrist Score: Preoperative, 51 (poor); postoperative, 68 (fair). Average postoperative DASH score was 19.5. Follow-up radiographs showed that 75% of patients had mild to no degeneration. Conclusions Osteochondral grafting in PRC offers satisfactory results in terms of pain relief, return to work, motion, and grip strength. Level of Evidence Therapeutic IV, Case series PMID:24436818

  11. Treatment of unstable osteochondritis dissecans in adults with autogenous osteochondral grafts (Mosaicplasty): long-term results

    PubMed Central

    RONGA, MARIO; STISSI, PLACIDO; LA BARBERA, GIUSEPPE; VALOROSO, MARCO; ANGERETTI, GLORIA; GENOVESE, EUGENIO; CHERUBINO, PAOLO

    2015-01-01

    Purpose the unstable osteochondritis dissecans (OCD-type II and III according to the ICRS classification) of the knee largher than > 2.5 cm2 in adults are uncommon lesions and there is no consensus on how to treat them. Medium-term studies have reported good results using autogenous osteochondral plugs (mosaicplasty). The aim of this study is to analyze the long-term results of this technique for the treatment of unstable OCD in a selected group of adult patients. Methods four patients with OCD at either one of the femoral condyles were included in this prospective study. The average age was 21.2 years (range, 18–24 years). The OCD lesions were classified as type II in three patients and type III in one patient and the average size was 3.8 cm2 (range, 2.55–5.1 cm2). The lesions were treated in situ with a variable number of autogenous osteochondral plugs (Ø 4.5 mm2). The Modified Cincinnati, Lysholm II and Tegner scores were used for clinical and functional evaluation. Magnetic resonance arthrography (MRA) was performed before surgery and at 2, 5 and 10 years after surgery. A modified MOCART score was used to evaluate MRA findings. Results the average follow-up duration was ten years and 6 months (range, 10–11 years). No complications occurred. At the final follow-up, all scores (clinical, functional and MOCART) improved. In all but one of the patients MRA showed complete osteochondral repair. Conclusions the fixation of large and unstable OCD lesions with mosaicplasty may be a good option for treating type II or III OCD lesions in adults. The advantages of this technique include stable fixation, promotion of blood supply to the base of the OCD fragment, and grafting of autologous cancellous bone that stimulates healing with preservation of the articular surface. Level of evidence Level IV, therapeutic case series. PMID:26904522

  12. Design and characterization of a tissue-engineered bilayer scaffold for osteochondral tissue repair.

    PubMed

    Giannoni, Paolo; Lazzarini, Erica; Ceseracciu, Luca; Barone, Alberto C; Quarto, Rodolfo; Scaglione, Silvia

    2015-10-01

    Treatment of full-thickness cartilage defects relies on osteochondral bilayer grafts, which mimic the microenvironment and structure of the two affected tissues: articular cartilage and subchondral bone. However, the integrity and stability of the grafts are hampered by the presence of a weak interphase, generated by the layering processes of scaffold manufacturing. We describe here the design and development of a bilayer monolithic osteochondral graft, avoiding delamination of the two distinct layers but preserving the cues for selective generation of cartilage and bone. A highly porous polycaprolactone-based graft was obtained by combining solvent casting/particulate leaching techniques. Pore structure and interconnections were designed to favour in vivo vascularization only at the bony layer. Hydroxyapatite granules were added as bioactive signals at the site of bone regeneration. Unconfined compressive tests displayed optimal elastic properties and low residual deformation of the graft after unloading (< 3%). The structural integrity of the graft was successfully validated by tension fracture tests, revealing high resistance to delamination, since fractures were never displayed at the interface of the layers (n = 8). Ectopic implantation of grafts in nude mice, after seeding with bovine trabecular bone-derived mesenchymal stem cells and bovine articular chondrocytes, resulted in thick areas of mature bone surrounding ceramic granules within the bony layer, and a cartilaginous alcianophilic matrix in the chondral layer. Vascularization was mostly observed in the bony layer, with a statistically significant higher blood vessel density and mean area. Thus, the easily generated osteochondral scaffolds, since they are mechanically and biologically functional, are suitable for tissue-engineering applications for cartilage repair. PMID:23172816

  13. CAN OSTEOCHONDRAL GRAFTING BE AUGMENTED WITH MICROFRACTURE IN AN EXTENDED SIZED LESION OF ARTICULAR CARTILAGE

    PubMed Central

    Lane, JG; Healey, RM; Sah, RL; Chen, AC-S; Amiel, D

    2014-01-01

    BACKGROUND Both microfracture and osteochondral autografting procedures have been useful in treating osteochondral lesions. HYPOTHESIS Combining microfracture and osteochondral autografting procedures can extend the size of lesions which can be treated with either technique. STUDY DESIGN Descriptive laboratory study. METHODS Eight adult goats underwent osteochondral autograft transfer of a 4.5mm femoral trochlea plug into an 8mm full thickness chondral defect in the weight bearing portion of the medial femoral condyle. In the gap region surrounding the autograft, microfracture was performed. The animals were allowed normal activity until the end of the experiment at 6 months, at which time the knees were harvested. At harvest the knees were assessed grossly, and then evaluation was performed by histology and histomorphometry, biochemistry and biomechanics. One animal died at 6 wks from gastroenteritis. RESULTS The osteochondral plugs healed well, with integration of the bone and preservation of the chondral cap. The chondral gap between the host site articular cartilage and the transferred plug had decreased from 3 mm at implant to less than 0.1 mm. Histological analysis demonstrated regions of variable cartilage repair, with integration of the cartilage layer at some sites but incomplete healing at others. Histomorphometry demonstrated filling of the chondral gap to 75–85% of the normal volume. Biochemical analysis revealed greater than 90% type II collagen at most sites with some areas containing 80% type II collagen. Biomechanical indentation testing, indicated that the repaired area had variable thickness and stiffness, with a trend of increased stiffness in the bulk graft and decreased softness at the proximal microfracture interface site. CONCLUSIONS The performance of a combined microfracture and osteochondral autograft transfer (OATS) procedure to resurface a large chondral defect appears promising. Transferred cartilage tissue can successfully be

  14. Effect of Impaction Sequence on Osteochondral Graft Damage: The Role of Repeated and Varying Loads

    PubMed Central

    Kang, Richard W.; Friel, Nicole A.; Williams, James M.; Cole, Brian J.; Wimmer, Markus A.

    2013-01-01

    Background Osteochondral autografts and allografts require mechanical force for proper graft placement into the defect site; however, impaction compromises the tissue. This study aimed to determine the effect of impaction force and number of hits to seat the graft on cartilage integrity. Hypothesis Under constant impulse conditions, higher impaction load magnitudes are more detrimental to cell viability, matrix integrity and collagen network organization and will result in proteoglycan loss and nitric oxide release. Study Design Controlled laboratory study Methods Osteochondral explants, harvested from fresh bovine trochleas, were exposed to a series of consistent impact loads delivered by a pneumatically driven device. Each plug received the same overall impulse of 7 Ns, reflecting the mean of 23 clinically inserted plugs. Impaction loads of 37.5N, 75N, 150N, and 300N were matched with 74, 37, 21, and 11 hits respectively. Following impaction, the plugs were harvested and cartilage was analyzed for cell viability, histology by safranin-o and picosirius red, and release of sulfated glycosaminoglycans and nitric oxide. Data were compared with non-impacted control. Results Impacted plugs had significantly lower cell viability than non-impacted plugs. A dose response relationship in loss of cell viability with respect to load magnitude was seen immediately and after 4 days but lost after 8 days. Histologic analysis revealed intact cartilage surface in all samples (loaded or control), with loaded samples showing alterations in birefringence. While the sulfated GAG release was similar across varying impaction loads, release of nitric oxide increased with increasing impaction magnitudes and time. Conclusions Impaction loading parameters have a direct effect on the time course of the viability of the cartilage in the graft tissue. Clinical Relevance Optimal loading parameters for surgical impaction of osteochondral grafts are those with lower load magnitudes and a greater

  15. Biofabrication of osteochondral tissue equivalents by printing topologically defined, cell-laden hydrogel scaffolds.

    PubMed

    Fedorovich, Natalja E; Schuurman, Wouter; Wijnberg, Hans M; Prins, Henk-Jan; van Weeren, P René; Malda, Jos; Alblas, Jacqueline; Dhert, Wouter J A

    2012-01-01

    Osteochondral defects are prone to induce osteoarthritic degenerative changes. Many tissue-engineering approaches that aim to generate osteochondral implants suffer from poor tissue formation and compromised integration. This illustrates the need for further improvement of heterogeneous tissue constructs. Engineering of these structures is expected to profit from strategies addressing the complexity of tissue organization and the simultaneous use of multiple cell types. Moreover, this enables the investigation of the effects of three-dimensional (3D) organization and architecture on tissue function. In the present study, we characterize the use of a 3D fiber deposition (3DF) technique for the fabrication of cell-laden, heterogeneous hydrogel constructs for potential use as osteochondral grafts. Changing fiber spacing or angle of fiber deposition yielded scaffolds of varying porosity and elastic modulus. We encapsulated and printed fluorescently labeled human chondrocytes and osteogenic progenitors in alginate hydrogel yielding scaffolds of 1×2 cm with different parts for both cell types. Cell viability remained high throughout the printing process, and cells remained in their compartment of the printed scaffold for the whole culture period. Moreover, distinctive tissue formation was observed, both in vitro after 3 weeks and in vivo (6 weeks subcutaneously in immunodeficient mice), at different locations within one construct. These results demonstrate the possibility of manufacturing viable centimeter-scaled structured tissues by the 3DF technique, which could potentially be used for the repair of osteochondral defects. PMID:21854293

  16. Mechanical effects of surgical procedures on osteochondral grafts elucidated by osmotic loading and real-time ultrasound

    PubMed Central

    2009-01-01

    Introduction Osteochondral grafts have become popular for treating small, isolated and full-thickness cartilage lesions. It is recommended that a slightly oversized, rather than an exact-sized, osteochondral plug is transplanted to achieve a tight fit. Consequently, impacting forces are required to insert the osteochondral plug into the recipient site. However, it remains controversial whether these impacting forces affect the biomechanical condition of the grafted articular cartilage. The present study aimed to investigate the mechanical effects of osteochondral plug implantation using osmotic loading and real-time ultrasound. Methods A full-thickness cylindrical osteochondral defect (diameter, 3.5 mm; depth, 5 mm) was created in the lateral lower quarter of the patella. Using graft-harvesting instruments, an osteochondral plug (diameter, 3.5 mm as exact-size or 4.5 mm as oversize; depth, 5 mm) was harvested from the lateral upper quarter of the patella and transplanted into the defect. Intact patella was used as a control. The samples were monitored by real-time ultrasound during sequential changes of the bathing solution from 0.15 M to 2 M saline (shrinkage phase) and back to 0.15 M saline (swelling phase). For cartilage sample assessment, three indices were selected, namely the change in amplitude from the cartilage surface (amplitude recovery rate: ARR) and the maximum echo shifts from the cartilage surface and the cartilage-bone interface. Results The ARR is closely related to the cartilage surface integrity, while the echo shifts from the cartilage surface and the cartilage-bone interface are closely related to tissue deformation and NaCl diffusion, respectively. The ARR values of the oversized plugs were significantly lower than those of the control and exact-sized plugs. Regarding the maximum echo shifts from the cartilage surface and the cartilage-bone interface, no significant differences were observed among the three groups. Conclusions These findings

  17. Effects of cryopreservation on the depth-dependent elastic modulus in articular cartilage and implications for osteochondral grafting.

    PubMed

    Kahn, David; Les, Clifford; Xia, Yang

    2015-05-01

    Cryopreservation of articular cartilage is often used in storage of experimental samples and osteochondral grafts, but the depth-dependence and concentration of glycosaminoglycan (GAG) are significantly altered when cryogenically stored without a cryoprotectant, which will reduce cartilage stiffness and affect osteochondral graft function and long-term viability. This study investigates our ability to detect changes due to cryopreservation in the depth-dependent elastic modulus of osteochondral samples. Using a direct-visualization method requiring minimal histological alterations, unconfined stepwise stress relaxation tests were performed on four fresh (never frozen) and three cryopreserved (-20 °C) canine humeral head osteochondral slices 125 ± 5 μm thick. Applied force was measured and tissue images were taken at the end of each relaxation phase using a 4× objective. Intratissue displacements were calculated by tracking chondrocytes through consecutive images for various intratissue depths. The depth-dependent elastic modulus was compared between fresh and cryopreserved tissue for same-depth ranges using analysis of variance (ANOVA) with Tukey post-test with a 95% confidence interval. Cryopreservation was found to significantly alter the force-displacement profile and reduce the depth-dependent modulus of articular cartilage. Excessive collagen fiber folding occurred at 40-60% relative depth, producing a "black line" in cryopreserved tissue. Force-displacement curves exhibited elongated toe-region in cryopreserved tissue while fresh tissue had nonmeasurable toe-region. Statistical analysis showed significant reduction in the elastic modulus and GAG concentration throughout the tissue between same-depth ranges. This method of cryopreservation significantly reduces the depth-dependent modulus of canine humeral osteochondral samples. PMID:25412272

  18. Early Postoperative Magnetic Resonance Imaging Findings After Autologous Osteochondral Plug Grafts For Osteochondritis Dissecans of the Humeral Capitellum

    PubMed Central

    Maruyama, Masahiro; Takahara, Masatoshi; Harada, Mikio; Satake, Hiroshi; Uno, Tomohiro; Takagi, Michiaki

    2016-01-01

    Objectives: Although good clinical outcomes of autologous osteochondral plug grafts for capitellar osteochondritis dissecans (OCD) have been reported, the timing of return to sports was various and still controversial. The period of graft incorporation and the lesion healing at repair site is important to establish the rehabilitation protocol, however there is little information. The aim of this study was to investigate early postoperative magnetic resonance imaging (MRI) findings and clinical outcomes after autologous osteochondral plug grafts for capitellar OCD. Methods: Fifteen young baseball players with advanced lesions of capitellar OCD underwent a procedure using autologous osteochondral plug grafts and underwent MRI (1.5 T) scan at 3 and 6 months, postoperatively. Their mean age at the time of surgery was 13.5 years (range, 13-15 years). Four lesions were classified as International Cartilage Repair Society (ICRS) OCD III and 11 lesions as OCD IV. The mean size of the lesions (sagittal × coronal) was 16 × 14 mm and the mean surface area was 181 mm2. One to two osteochondral plug grafts, with a mean diameter of 7 mm (range, 6-8 mm), were harvested from the lateral femoral condyle and transplanted to the defects. The mean reconstruction rate was 41% (range, 12%-65%), which was calculated as (total surface area of the grafts × 100%)/ (surface area of the lesion). Patients were allowed to begin throwing after 3 months and to return to sports after 6 months. The mean follow-up was 21 months (range, 12-36 months). The MRI findings were assessed graft incorporation, which was indicated by no T1-low-signal-intensity at the graft and no fluid surrounding the graft on T2-weighted fat-suppression (Figure 1), and the lesion healing according to the scoring system of Henderson (4, complete healing; 16, no healing). MRI were blinded and randomized, and two observers reviewed independently and conferred when they differed. Clinical outcomes were evaluated as elbow pain

  19. Effect of tissue culture storage on the in vivo survival of canine osteochondral allografts.

    PubMed

    Oates, K M; Chen, A C; Young, E P; Kwan, M K; Amiel, D; Convery, F R

    1995-07-01

    In vitro studies in our laboratory have shown that the biomechanical and biochemical characteristics of osteochondral grafts can be preserved for as long as 28 days under tissue culture conditions. This study represents an attempt to extend these results to an in vivo model. In adult mongrel dogs, either an autograft, a fresh allograft, or a stored allograft was placed in a standardized defect on the weight-bearing surface of the medial femoral condyle. The stored grafts were kept at 4 degrees C in tissue culture medium for 14 days prior to implantation. The animals were killed at 12 weeks. Cartilage from the contralateral knee served as a control. The modulus and permeability of the cartilage were assessed with confined compression creep tests. The collagen and glycosaminoglycan contents were measured, and the cartilage was analyzed histologically with hematoxylin and eosin and safranin O stains. Grossly, the cartilage appeared viable at harvest. The histologic results were similar in the treatment groups, with the same spectrum of mild degenerative changes being noted in each group. The glycosaminoglycan content was significantly less in the autograft group than in its control group and than in the fresh allograft group. The glycosaminoglycan content did not differ significantly between fresh and stored allografts. The collagen content, modulus, and permeability did not differ either between experimental and control groups or between graft types. Our results support the conclusion that osteochondral allografts can be stored for as many as 14 days without significantly affecting the results of the procedure. PMID:7674072

  20. A Hydrogel-Mineral Composite Scaffold for Osteochondral Interface Tissue Engineering

    PubMed Central

    Khanarian, Nora T.; Jiang, Jie; Wan, Leo Q.; Mow, Van C.

    2012-01-01

    Osteoarthritis is the leading cause of physical disability among Americans, and tissue engineered cartilage grafts have emerged as a promising treatment option for this debilitating condition. Currently, the formation of a stable interface between the cartilage graft and subchondral bone remains a significant challenge. This study evaluates the potential of a hybrid scaffold of hydroxyapatite (HA) and alginate hydrogel for the regeneration of the osteochondral interface. Specifically, the effects of HA on the response of chondrocytes were determined, focusing on changes in matrix production and mineralization, as well as scaffold mechanical properties over time. Additionally, the optimal chondrocyte population for interface tissue engineering was evaluated. It was observed that the HA phase of the composite scaffold promoted the formation of a proteoglycan- and type II collagen–rich matrix when seeded with deep zone chondrocytes. More importantly, the elevated biosynthesis translated into significant increases in both compressive and shear moduli relative to the mineral-free control. Presence of HA also promoted chondrocyte hypertrophy and type X collagen deposition. These results demonstrate that the hydrogel–calcium phosphate composite supported the formation of a calcified cartilage-like matrix and is a promising scaffold design for osteochondral interface tissue engineering. PMID:21919797

  1. Viral Inactivation of Human Osteochondral Grafts with Methylene Blue and Light

    PubMed Central

    Zhao, Zhixing; Call, Gazell M.; Gao, Jizong; Yao, Jian Q.

    2014-01-01

    Objective: Cartilage injury is one of the most common disorders of synovial joints. Fresh osteochondral allografts are becoming a standard treatment; however, they are supply constrained with a potential risk of disease transmission. There are no known virucidal processes available for osteochondral allografts and most methods presently available are detrimental to cartilage. Methylene blue light treatment has been shown to be successful in the literature for viral inactivation of fresh frozen plasma. The purpose of this study was to determine the capacity of methylene blue light treatment to inactivate a panel of clinically relevant viruses inoculated onto osteochondral allografts. Design: Osteochondral grafts recovered from human cadaveric knees were inoculated with one of the following viruses: bovine viral diarrhea virus (BVDV), hepatitis A virus (HAV), human immunodeficiency virus type 1 (HIV-1), porcine parvovirus (PPV), and pseudorabies virus (PrV). The samples were processed through a methylene blue light treatment, which consisted of an initial soak in nonilluminated circulating methylene blue at ambient temperature, followed by light exposure with circulating methylene blue at cool temperatures. The final titer was compared with the recovery control for the viral log reduction. Results: HIV-1, BVDV, and PrV were reduced to nondetectable levels while HAV and PPV were reduced by 3.1 and 5.6 logs, respectively. Conclusions: The methylene blue light treatment was effective in reducing (a) enveloped DNA and RNA viruses to nondetectable levels and (b) nonenveloped DNA and RNA viruses of inoculated human osteochondral grafts by 3.1 to 5.6 logs. This study demonstrates the first practical method for significantly reducing viral load in osteochondral implants. PMID:26069682

  2. Osteochondral tissue engineering: scaffolds, stem cells and applications

    PubMed Central

    Nooeaid, Patcharakamon; Salih, Vehid; Beier, Justus P; Boccaccini, Aldo R

    2012-01-01

    Osteochondral tissue engineering has shown an increasing development to provide suitable strategies for the regeneration of damaged cartilage and underlying subchondral bone tissue. For reasons of the limitation in the capacity of articular cartilage to self-repair, it is essential to develop approaches based on suitable scaffolds made of appropriate engineered biomaterials. The combination of biodegradable polymers and bioactive ceramics in a variety of composite structures is promising in this area, whereby the fabrication methods, associated cells and signalling factors determine the success of the strategies. The objective of this review is to present and discuss approaches being proposed in osteochondral tissue engineering, which are focused on the application of various materials forming bilayered composite scaffolds, including polymers and ceramics, discussing the variety of scaffold designs and fabrication methods being developed. Additionally, cell sources and biological protein incorporation methods are discussed, addressing their interaction with scaffolds and highlighting the potential for creating a new generation of bilayered composite scaffolds that can mimic the native interfacial tissue properties, and are able to adapt to the biological environment. PMID:22452848

  3. Reconstruction of Osteochondral Defects by Combined Bone Grafting and a Bilayer Collagen Membrane as a Sandwich Technique

    PubMed Central

    Petri, Maximilian; Ettinger, Max; von Falck, Christian; Hawi, Nael; Jagodzinski, Michael; Haasper, Carl

    2013-01-01

    Treatment of osteochondral lesions of the knee remains a major challenge in orthopedic surgery. Recently established procedures like autologous chondrocyte implantation or matrix-associated chondrocyte implantation yield good results, but include the disadvantage of two-step procedures. The purpose of this study was to evaluate the clinical and magnetic resonance imaging outcome of repairs of osteochondral defects of the knee by a combined procedure of bone grafting and covering with a bilayer collagen membrane in a sandwich technique. Seven male patients with a mean age of 42 (range 30-55) years and symptomatic focal osteochondral lesions of the knee grade IV according to the International Cartilage Repair Society classification were included. The mean diameter of defects was 28.6 (range 15-40) mm. Results were evaluated at a minimum of 24 months after surgery by International Knee Documentation Committee score, Lysholm-score, visual analogue scale, and magnetic resonance imaging with specific cartilage sequences, evaluating the ICRS score and the Magnetic Observation of Cartilage Repair Tissue (MOCART) score. All patients judged the operation as successful. Among the patients available for the long-term follow-up, mean visual analogue scale value was 1.3 (range 0-3) out of 10 points. Mean International Knee Documentation Committee score was 80.8 (range 63.2-88.5) out of 100 points. Mean Lysholm score was 85 (range 55-95) out of 100 points. None of the patients had to be reoperated until today. Evaluation of magnetic resonance imaging using the MOCART score revealed a good correlation to the clinical outcome. This is the first study reporting results after reconstruction of osteochondral defects of the knee joint by bone grafting and a bilayer collagen membrane. This new method offers the advantage of a one-step-procedure and yields both good clinical and magnetic resonance findings. We conclude that this procedure can be a valuable tool to improve joint function

  4. Effect of the Presence of Subchondral Cysts on Treatment Results of Autologous Osteochondral Graft Transfer in Osteochondral Lesions of the Talus.

    PubMed

    Gül, Murat; Çetinkaya, Engin; Aykut, Ümit Selçuk; Özkul, Barış; Saygılı, Mehmet Selçuk; Akman, Yunus Emre; Kabukcuoglu, Yavuz Selim

    2016-01-01

    The aim of the present study was to clinically evaluate whether the presence of subchondral cysts had an effect on the treatment results of autologous osteochondral graft transfer in osteochondral lesions of the talus. Patients were enrolled in the present study according to the inclusion criteria. In the evaluation, we divided the patients into 2 groups according to presence (n = 13 patients) or absence (n = 15 patients) of a subchondral cyst. The mean age, body mass index, follow-up period, and lesion size in each group were measured and compared, and no statistically significant differences were found between the 2 groups (p > .05). The clinical assessment was performed using the American Orthopaedic Foot and Ankle Society Hindfoot scoring system, visual analog scale, and International Knee Society scoring system. No statistically significant difference was found between the pre- and postoperative scores of the 2 patient groups (p > .05). The successful results in both groups after a 2-year follow-up period have demonstrated that treatment of osteochondral lesions of the talus with osteochondral graft transfer is a safe method that can be performed independently of the presence of a subchondral cyst. PMID:27432027

  5. Spectrocolorimetric assessment of cartilage plugs after autologous osteochondral grafting: correlations between color indices and histological findings in a rabbit model

    PubMed Central

    Hattori, Koji; Uematsu, Kota; Tanikake, Yohei; Habata, Takashi; Tanaka, Yasuhito; Yajima, Hiroshi; Takakura, Yoshinori

    2007-01-01

    We investigated the use of a commercial spectrocolorimeter and the application of two color models (L* a* b* colorimetric system and spectral reflectance distribution) to describe and quantify cartilage plugs in a rabbit model of osteochondral autografting. Osteochondral plugs were removed and then replaced in their original positions in Japanese white rabbits. The rabbits were sacrificed at 4 or 12 weeks after the operation and cartilage samples were assessed using a spectrocolorimeter. The samples were retrospectively divided into two groups on the basis of the histological findings (group H: hyaline cartilage, successful; group F: fibrous tissue or fibrocartilage, failure) and investigated for possible significant differences in the spectrocolorimetric analyses between the two groups. Moreover, the relationships between the spectrocolorimetric indices and the Mankin histological score were examined. In the L* a* b* colorimetric system, the L* values were significantly lower in group H than in group F (P = 0.02), whereas the a* values were significantly higher in group H than in group F (P = 0.006). Regarding the spectral reflectance distribution, the spectral reflectance percentage 470 (SRP470) values, as a coincidence index for the spectral reflectance distribution (400 to 470 nm in wavelength) of the cartilage plugs with respect to intact cartilage, were 99.8 ± 6.7% in group H and 119.8 ± 10.6% in group F, and the difference between these values was significant (P = 0.005). Furthermore, the a* values were significantly correlated with the histological score (P = 0.004, r = -0.76). The SRP470 values were also significantly correlated with the histological score (P = 0.01, r = 0.67). Our findings demonstrate the ability of spectrocolorimetric measurements to predict the histological findings of cartilage plugs after autologous osteochondral grafting. In particular, the a* values and SRP470 values can be used to judge the surface condition of an osteochondral

  6. The Impact of Compact Layer in Biphasic Scaffold on Osteochondral Tissue Engineering

    PubMed Central

    Cheng, Jian-Hua; Zhou, Wei; Xiong, Zhuo; Mu, Yun-Jing; Liu, Jian

    2013-01-01

    The structure of an osteochondral biphasic scaffold is required to mimic native tissue, which owns a calcified layer associated with mechanical and separation function. The two phases of biphasic scaffold should possess efficient integration to provide chondrocytes and osteocytes with an independent living environment. In this study, a novel biphasic scaffold composed of a bony phase, chondral phase and compact layer was developed. The compact layer-free biphasic scaffold taken as control group was also fabricated. The purpose of current study was to evaluate the impact of the compact layer in the biphasic scaffold. Bony and chondral phases were seeded with autogeneic osteoblast- or chondrocyte-induced bone marrow stromal cells (BMSCs), respectively. The biphasic scaffolds-cells constructs were then implanted into osteochondral defects of rabbits’ knees, and the regenerated osteochondral tissue was evaluated at 3 and 6 months after surgery. Anti-tensile and anti-shear properties of the compact layer-containing biphasic scaffold were significantly higher than those of the compact layer-free biphasic scaffold in vitro. Furthermore, in vivo studies revealed superior macroscopic scores, glycosaminoglycan (GAG) and collagen content, micro tomograph imaging results, and histological properties of regenerated tissue in the compact layer-containing biphasic scaffold compared to the control group. These results indicated that the compact layer could significantly enhance the biomechanical properties of biphasic scaffold in vitro and regeneration of osteochondral tissue in vivo, and thus represented a promising approach to osteochondral tissue engineering. PMID:23382984

  7. Advancements in Orthopedic Intervention: Retrograde Drilling and Bone Grafting of Osteochondral Lesions of the Knee Using Magnetic Resonance Imaging Guidance

    SciTech Connect

    Seebauer, Christian J.; Bail, Hermann J.; Rump, Jens C. Walter, Thula Teichgraeber, Ulf K. M.

    2010-12-15

    Computer-assisted surgery is currently a novel challenge for surgeons and interventional radiologists. Magnetic resonance imaging (MRI)-guided procedures are still evolving. In this experimental study, we describe and assess an innovative passive-navigation method for MRI-guided treatment of osteochondritis dissecans of the knee. A navigation principle using a passive-navigation device was evaluated in six cadaveric knee joint specimens for potential applicability in retrograde drilling and bone grafting of osteochondral lesions using MRI guidance. Feasibility and accuracy were evaluated in an open MRI scanner (1.0 T Philips Panorama HFO MRI System). Interactive MRI navigation allowed precise drilling and bone grafting of osteochondral lesions of the knee. All lesions were hit with an accuracy of 1.86 mm in the coronal plane and 1.4 mm the sagittal plane. Targeting of all lesions was possible with a single drilling. MRI allowed excellent assessment of correct positioning of the cancellous bone cylinder during bone grafting. The navigation device and anatomic structures could be clearly identified and distinguished throughout the entire drilling procedure. MRI-assisted navigation method using a passive navigation device is feasible for the treatment of osteochondral lesions of the knee under MRI guidance and allows precise and safe drilling without exposure to ionizing radiation. This method may be a viable alternative to other navigation principles, especially for pediatric and adolescent patients. This MRI-navigated method is also potentially applicable in many other MRI-guided interventions.

  8. Osteochondral allograft transplantation in cartilage repair: Graft storage paradigm, translational models, and clinical applications.

    PubMed

    Bugbee, William D; Pallante-Kichura, Andrea L; Görtz, Simon; Amiel, David; Sah, Robert

    2016-01-01

    The treatment of articular cartilage injury and disease has become an increasingly relevant part of orthopaedic care. Articular cartilage transplantation, in the form of osteochondral allografting, is one of the most established techniques for restoration of articular cartilage. Our research efforts over the last two decades have supported the transformation of this procedure from experimental "niche" status to a cornerstone of orthopaedic practice. In this Kappa Delta paper, we describe our translational and clinical science contributions to this transformation: (1) to enhance the ability of tissue banks to process and deliver viable tissue to surgeons and patients, (2) to improve the biological understanding of in vivo cartilage and bone remodeling following osteochondral allograft (OCA) transplantation in an animal model system, (3) to define effective surgical techniques and pitfalls, and (4) to identify and clarify clinical indications and outcomes. The combination of coordinated basic and clinical studies is part of our continuing comprehensive academic OCA transplant program. Taken together, the results have led to the current standards for OCA processing and storage prior to implantation and also novel observations and mechanisms of the biological and clinical behavior of OCA transplants in vivo. Thus, OCA transplantation is now a successful and increasingly available treatment for patients with disabling osteoarticular cartilage pathology. PMID:26234194

  9. Stem cell-based microphysiological osteochondral system to model tissue response to interleukin-1β.

    PubMed

    Lin, Hang; Lozito, Thomas P; Alexander, Peter G; Gottardi, Riccardo; Tuan, Rocky S

    2014-07-01

    Osteoarthritis (OA) is a chronic degenerative disease of the articular joint that involves both bone and cartilage degenerative changes. An engineered osteochondral tissue within physiological conditions will be of significant utility in understanding the pathogenesis of OA and testing the efficacy of potential disease-modifying OA drugs (DMOADs). In this study, a multichamber bioreactor was fabricated and fitted into a microfluidic base. When the osteochondral construct is inserted, two chambers are formed on either side of the construct (top, chondral; bottom, osseous) that is supplied by different medium streams. These medium conduits are critical to create tissue-specific microenvironments in which chondral and osseous tissues will develop and mature. Human bone marrow stem cell (hBMSCs)-derived constructs were fabricated in situ and cultured within the bioreactor and induced to undergo spatially defined chondrogenic and osteogenic differentiation for 4 weeks in tissue-specific media. We observed tissue specific gene expression and matrix production as well as a basophilic interface suggesting a developing tidemark. Introduction of interleukin-1β (IL-1β) to either the chondral or osseous medium stream induced stronger degradative responses locally as well as in the opposing tissue type. For example, IL-1β treatment of the osseous compartment resulted in a strong catabolic response in the chondral layer as indicated by increased matrix metalloproteinase (MMP) expression and activity, and tissue-specific gene expression. This induction was greater than that seen with IL-1β application to the chondral component directly, indicative of active biochemical communication between the two tissue layers and supporting the osteochondral nature of OA. The microtissue culture system developed here offers novel capabilities for investigating the physiology of osteochondral tissue and pathogenic mechanisms of OA and serving as a high-throughput platform to test potential

  10. Stem Cell-Based Microphysiological Osteochondral System to Model Tissue Response to Interleukin-1β

    PubMed Central

    2015-01-01

    Osteoarthritis (OA) is a chronic degenerative disease of the articular joint that involves both bone and cartilage degenerative changes. An engineered osteochondral tissue within physiological conditions will be of significant utility in understanding the pathogenesis of OA and testing the efficacy of potential disease-modifying OA drugs (DMOADs). In this study, a multichamber bioreactor was fabricated and fitted into a microfluidic base. When the osteochondral construct is inserted, two chambers are formed on either side of the construct (top, chondral; bottom, osseous) that is supplied by different medium streams. These medium conduits are critical to create tissue-specific microenvironments in which chondral and osseous tissues will develop and mature. Human bone marrow stem cell (hBMSCs)-derived constructs were fabricated in situ and cultured within the bioreactor and induced to undergo spatially defined chondrogenic and osteogenic differentiation for 4 weeks in tissue-specific media. We observed tissue specific gene expression and matrix production as well as a basophilic interface suggesting a developing tidemark. Introduction of interleukin-1β (IL-1β) to either the chondral or osseous medium stream induced stronger degradative responses locally as well as in the opposing tissue type. For example, IL-1β treatment of the osseous compartment resulted in a strong catabolic response in the chondral layer as indicated by increased matrix metalloproteinase (MMP) expression and activity, and tissue-specific gene expression. This induction was greater than that seen with IL-1β application to the chondral component directly, indicative of active biochemical communication between the two tissue layers and supporting the osteochondral nature of OA. The microtissue culture system developed here offers novel capabilities for investigating the physiology of osteochondral tissue and pathogenic mechanisms of OA and serving as a high-throughput platform to test potential

  11. Spatial Engineering of Osteochondral Tissue Constructs Through Microfluidically Directed Differentiation of Mesenchymal Stem Cells.

    PubMed

    Goldman, Stephen M; Barabino, Gilda A

    2016-01-01

    The development of tissue engineered osteochondral units has been slowed by a number of technical hurdles associated with recapitulating their heterogeneous nature ex vivo. Subsequently, numerous approaches with respect to cell sourcing, scaffolding composition, and culture media formulation have been pursued, which have led to high variability in outcomes and ultimately the lack of a consensus bioprocessing strategy. As such, the objective of this study was to standardize the design process by focusing on differentially supporting formation of cartilaginous and bony matrix by a single cell source in a spatially controlled manner within a single material system. A cell-polymer solution of bovine mesenchymal stem cells and agarose was cast against micromolds of a serpentine network and stacked to produce tissue constructs containing two independent microfluidic networks. Constructs were fluidically connected to two controlled flow loops and supplied with independently tuned differentiation parameters for chondrogenic and osteogenic induction, respectively. Constructs receiving inductive media showed differential gene expression of both chondrogenic and osteogenic markers in opposite directions along the thickness of the construct that was recapitulated at the protein level with respect to collagens I, II, and X. A control group receiving noninductive media showed homogeneous expression of these biomarkers measured in lower concentrations at both the mRNA and protein level. This work represents an important step in the rational design of engineered osteochondral units through establishment of an enabling technology for further optimization of scaffolding formulations and bioprocessing conditions toward the production of commercially viable osteochondral tissue products. PMID:27190700

  12. Spatial Engineering of Osteochondral Tissue Constructs Through Microfluidically Directed Differentiation of Mesenchymal Stem Cells

    PubMed Central

    Goldman, Stephen M.; Barabino, Gilda A.

    2016-01-01

    Abstract The development of tissue engineered osteochondral units has been slowed by a number of technical hurdles associated with recapitulating their heterogeneous nature ex vivo. Subsequently, numerous approaches with respect to cell sourcing, scaffolding composition, and culture media formulation have been pursued, which have led to high variability in outcomes and ultimately the lack of a consensus bioprocessing strategy. As such, the objective of this study was to standardize the design process by focusing on differentially supporting formation of cartilaginous and bony matrix by a single cell source in a spatially controlled manner within a single material system. A cell-polymer solution of bovine mesenchymal stem cells and agarose was cast against micromolds of a serpentine network and stacked to produce tissue constructs containing two independent microfluidic networks. Constructs were fluidically connected to two controlled flow loops and supplied with independently tuned differentiation parameters for chondrogenic and osteogenic induction, respectively. Constructs receiving inductive media showed differential gene expression of both chondrogenic and osteogenic markers in opposite directions along the thickness of the construct that was recapitulated at the protein level with respect to collagens I, II, and X. A control group receiving noninductive media showed homogeneous expression of these biomarkers measured in lower concentrations at both the mRNA and protein level. This work represents an important step in the rational design of engineered osteochondral units through establishment of an enabling technology for further optimization of scaffolding formulations and bioprocessing conditions toward the production of commercially viable osteochondral tissue products. PMID:27190700

  13. Mechanical loading regulates human MSC differentiation in a multi-layer hydrogel for osteochondral tissue engineering.

    PubMed

    Steinmetz, Neven J; Aisenbrey, Elizabeth A; Westbrook, Kristofer K; Qi, H Jerry; Bryant, Stephanie J

    2015-07-01

    A bioinspired multi-layer hydrogel was developed for the encapsulation of human mesenchymal stem cells (hMSCs) as a platform for osteochondral tissue engineering. The spatial presentation of biochemical cues, via incorporation of extracellular matrix analogs, and mechanical cues, via both hydrogel crosslink density and externally applied mechanical loads, were characterized in each layer. A simple sequential photopolymerization method was employed to form stable poly(ethylene glycol)-based hydrogels with a soft cartilage-like layer of chondroitin sulfate and low RGD concentrations, a stiff bone-like layer with high RGD concentrations, and an intermediate interfacial layer. Under a compressive load, the variation in hydrogel stiffness within each layer produced high strains in the soft cartilage-like layer, low strains in the stiff bone-like layer, and moderate strains in the interfacial layer. When hMSC-laden hydrogels were cultured statically in osteochondral differentiation media, the local biochemical and matrix stiffness cues were not sufficient to spatially guide hMSC differentiation after 21 days. However dynamic mechanical stimulation led to differentially high expression of collagens with collagen II in the cartilage-like layer, collagen X in the interfacial layer and collagen I in the bone-like layer and mineral deposits localized to the bone layer. Overall, these findings point to external mechanical stimulation as a potent regulator of hMSC differentiation toward osteochondral cellular phenotypes. PMID:25900444

  14. A novel, visible light-induced, rapidly cross-linkable gelatin scaffold for osteochondral tissue engineering

    PubMed Central

    Mazaki, Tetsuro; Shiozaki, Yasuyuki; Yamane, Kentaro; Yoshida, Aki; Nakamura, Mariko; Yoshida, Yasuhiro; Zhou, Di; Kitajima, Takashi; Tanaka, Masato; Ito, Yoshihiro; Ozaki, Toshifumi; Matsukawa, Akihiro

    2014-01-01

    Osteochondral injuries remain difficult to repair. We developed a novel photo-cross-linkable furfurylamine-conjugated gelatin (gelatin-FA). Gelatin-FA was rapidly cross-linked by visible light with Rose Bengal, a light sensitizer, and was kept gelled for 3 weeks submerged in saline at 37°C. When bone marrow-derived stromal cells (BMSCs) were suspended in gelatin-FA with 0.05% Rose Bengal, approximately 87% of the cells were viable in the hydrogel at 24 h after photo-cross-linking, and the chondrogenic differentiation of BMSCs was maintained for up to 3 weeks. BMP4 fusion protein with a collagen binding domain (CBD) was retained in the hydrogels at higher levels than unmodified BMP4. Gelatin-FA was subsequently employed as a scaffold for BMSCs and CBD-BMP4 in a rabbit osteochondral defect model. In both cases, the defect was repaired with articular cartilage-like tissue and regenerated subchondral bone. This novel, photo-cross-linkable gelatin appears to be a promising scaffold for the treatment of osteochondral injury. PMID:24662725

  15. Multiphasic construct studied in an ectopic osteochondral defect model

    PubMed Central

    Jeon, June E.; Vaquette, Cédryck; Theodoropoulos, Christina; Klein, Travis J.; Hutmacher, Dietmar W.

    2014-01-01

    In vivo osteochondral defect models predominantly consist of small animals, such as rabbits. Although they have an advantage of low cost and manageability, their joints are smaller and more easily healed compared with larger animals or humans. We hypothesized that osteochondral cores from large animals can be implanted subcutaneously in rats to create an ectopic osteochondral defect model for routine and high-throughput screening of multiphasic scaffold designs and/or tissue-engineered constructs (TECs). Bovine osteochondral plugs with 4 mm diameter osteochondral defect were fitted with novel multiphasic osteochondral grafts composed of chondrocyte-seeded alginate gels and osteoblast-seeded polycaprolactone scaffolds, prior to being implanted in rats subcutaneously with bone morphogenic protein-7. After 12 weeks of in vivo implantation, histological and micro-computed tomography analyses demonstrated that TECs are susceptible to mineralization. Additionally, there was limited bone formation in the scaffold. These results suggest that the current model requires optimization to facilitate robust bone regeneration and vascular infiltration into the defect site. Taken together, this study provides a proof-of-concept for a high-throughput osteochondral defect model. With further optimization, the presented hybrid in vivo model may address the growing need for a cost-effective way to screen osteochondral repair strategies before moving to large animal preclinical trials. PMID:24694896

  16. Multiphasic construct studied in an ectopic osteochondral defect model.

    PubMed

    Jeon, June E; Vaquette, Cédryck; Theodoropoulos, Christina; Klein, Travis J; Hutmacher, Dietmar W

    2014-06-01

    In vivo osteochondral defect models predominantly consist of small animals, such as rabbits. Although they have an advantage of low cost and manageability, their joints are smaller and more easily healed compared with larger animals or humans. We hypothesized that osteochondral cores from large animals can be implanted subcutaneously in rats to create an ectopic osteochondral defect model for routine and high-throughput screening of multiphasic scaffold designs and/or tissue-engineered constructs (TECs). Bovine osteochondral plugs with 4 mm diameter osteochondral defect were fitted with novel multiphasic osteochondral grafts composed of chondrocyte-seeded alginate gels and osteoblast-seeded polycaprolactone scaffolds, prior to being implanted in rats subcutaneously with bone morphogenic protein-7. After 12 weeks of in vivo implantation, histological and micro-computed tomography analyses demonstrated that TECs are susceptible to mineralization. Additionally, there was limited bone formation in the scaffold. These results suggest that the current model requires optimization to facilitate robust bone regeneration and vascular infiltration into the defect site. Taken together, this study provides a proof-of-concept for a high-throughput osteochondral defect model. With further optimization, the presented hybrid in vivo model may address the growing need for a cost-effective way to screen osteochondral repair strategies before moving to large animal preclinical trials. PMID:24694896

  17. Harnessing Cell–Biomaterial Interactions for Osteochondral Tissue Regeneration

    PubMed Central

    Kim, Kyobum; Yoon, Diana M.; Mikos, Antonios G.

    2013-01-01

    Articular cartilage that is damaged or diseased often requires surgical intervention to repair the tissue; therefore, tissue engineering strategies have been developed to aid in cartilage regeneration. Tissue engineering approaches often require the integration of cells, biomaterials, and growth factors to direct and support tissue formation. A variety of cell types have been isolated from adipose, bone marrow, muscle, and skin tissue to promote cartilage regeneration. The interaction of cells with each other and with their surrounding environment has been shown to play a key role in cartilage engineering. In tissue engineering approaches, biomaterials are commonly used to provide an initial framework for cell recruitment and proliferation and tissue formation. Modifications of the properties of biomaterials, such as creating sites for cell binding, altering their physicochemical characteristics, and regulating the delivery of growth factors, can have a significant influence on chondrogenesis. Overall, the goal is to completely restore healthy cartilage within an articular cartilage defect. This chapter aims to provide information about the importance of cell–biomaterial interactions for the chondrogenic differentiation of various cell populations that can eventually produce functional cartilage matrix that is indicative of healthy cartilage tissue. PMID:21975954

  18. Evaluation of cartilage, synovium and adipose tissue as cellular sources for osteochondral repair.

    PubMed

    Innes, J F; Gordon, C; Vaughan-Thomas, A; Rhodes, N P; Clegg, P D

    2013-09-01

    Osteochondral lesions are a major cause of pain and disability in several species including dogs, horses and human beings. The objective of this study was to assess three potential sources of canine cells for their osteochondral regenerative potential. Cartilage, synovium and adipose tissue cells were grown in pellet culture in chondrogenic or osteogenic media. Cartilage-derived pellets displayed the best chondrogenic differentiation as indicated by significantly higher COL2A1 and SOX9 mRNA expression, greater glycosaminoglycan content, and higher retention of Safranin-O stain compared to the synovium and adipose-derived cells. Following application of the osteogenic media, all three cell sources exhibited small areas of positive alizarin red staining. Poor intracellular alkaline phosphatase activity was found in all three cell types when stimulated although osteocalcin and RUNX2 expression were significantly increased. Cells isolated and cultured from canine articular cartilage retained their specific chondrocytic phenotype. Furthermore, canine adipocytes and synovial cells did not undergo chondrogenic differentiation and did not exhibit evidence of multipotency. Although osteogenic differentiation was initiated at a genomic level, phenotypic osteoblastic differentiation was not observed. The findings of this study suggest that cells isolated from canine adipose tissue and synovium are sub-optimal substitutes for chondrocytes when engineering articular cartilage in vitro. PMID:23886701

  19. In vitro generation of a multilayered osteochondral construct with an osteochondral interface using rabbit bone marrow stromal cells and a silk peptide-based scaffold.

    PubMed

    Chen, Kelei; Shi, Pujiang; Teh, Thomas Kok Hiong; Toh, Siew Lok; Goh, James Ch

    2016-04-01

    Tissue engineering of a biological osteochondral multilayered construct with a cartilage-interface subchondral bone layer is a key challenge. This study presented a rabbit bone marrow stromal cell (BMSC)/silk fibroin scaffold-based co-culture approach to generate tissue-engineered osteochondral grafts with an interface. BMSC-seeded scaffolds were first cultured separately in osteogenic and chondrogenic stimulation media. The two differentiated pieces were then combined using an RADA self-assembling peptide and subsequently co-cultured. Gene expression, histological and biochemical analyses were used to evaluate the multilayered structure of the osteochondral graft. A complete osteochondral construct with a cartilage-subchondral bone interface was regenerated and BMSCs were used as the only cell source for the osteochondral construct and interface regeneration. Furthermore, in the intermediate region of co-cultured samples, hypertrophic chondrogenic gene markers type X collagen and MMP-13 were found on both chondrogenic and osteogenic section edges after co-culture. However, significant differences gene expression profile were found in distinct zones of the construct during co-culture and the section in the intermediate region had significantly higher hypertrophic chondrocyte gene expression. Biochemical analyses and histology results further supported this observation. This study showed that specific stimulation from osteogenic and chondrogenic BMSCs affected each other in this co-culture system and induced the formation of an osteochondral interface. Moreover, this system provided a possible approach for generating multilayered osteochondral constructs. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23413023

  20. Bioglass®/chitosan-polycaprolactone bilayered composite scaffolds intended for osteochondral tissue engineering.

    PubMed

    Yao, Qingqing; Nooeaid, Patcharakamon; Detsch, Rainer; Roether, Judith A; Dong, Yanming; Goudouri, Ourania-Menti; Schubert, Dirk W; Boccaccini, Aldo R

    2014-12-01

    Polymer-coated 45S5 Bioglass(®) (BG)/chitosan-polycaprolactone (BG/CS-PCL) bilayered composite scaffolds were prepared via foam replication and freeze-drying techniques for application in osteochondral tissue engineering. The CS-PCL coated and uncoated BG scaffolds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The mechanical properties of the coated scaffolds were significantly improved in comparison to uncoated scaffolds. The bioactivity and biodegradation behavior of scaffolds were studied in simulated body fluid (SBF) for up to 28 days. The interface between the BG scaffold and the polymer coating layer was observed by SEM and a suitable interpenetration of the polymer into the scaffold struts was found. The effects of coated and uncoated BG scaffolds on MG-63 osteoblast-like cells were evaluated by cell viability, adhesion and proliferation. PMID:24677705

  1. Novel nanostructured scaffold for osteochondral regeneration: pilot study in horses.

    PubMed

    Kon, E; Mutini, A; Arcangeli, E; Delcogliano, M; Filardo, G; Nicoli Aldini, N; Pressato, D; Quarto, R; Zaffagnini, S; Marcacci, M

    2010-06-01

    The present in vivo preliminary experiment is aimed at testing mechanical and biological behaviour of a new nano-structured composite multilayer biomimetic scaffold for the treatment of chondral and osteochondral defects. The three-dimensional biomimetic scaffold (Fin-Ceramica Faenza S.p.A., Faenza-Italy) was obtained by nucleating collagen fibrils with hydroxyapatite nanoparticles, in two configurations, bi- and tri-layered, to reproduce, respectively, chondral and osteochondral anatomy. Chondral defects (lateral condyle) and deep osteochondral defects (medial condyle) were made in the distal epiphysis of the third metacarpal bone of both forelimbs of two adult horses and treated respectively with the chondral and osteochondral grafts. Both animals were euthanised six months follow up. The images obtained at the second look arthroscopy evaluation, performed two months after surgery, demonstrated good filling of the chondral and osteo-chondral defects without any inflammatory reaction around and inside the lesions. At the histological analysis the growth of trabecular bone in the osteochondral lesion was evident. Only in one case, the whole thickness of the osteochondral lesion was filled by fibrocartilaginous tissue. The formation of a tidemark line was evident at the interface with the newly formed bone. Newly formed fibrocartilaginous tissue was present in the area of the chondral defect. Initial alignment of the collagen fibres was recognisable with polarised light in both groups. The results of the present pilot study showed that this novel osteochondral and chondral scaffold may act as a suitable matrix to facilitate orderly regeneration of bone and hyaline-like cartilage. PMID:20049745

  2. Treatment of extended osteochondral lesions of the talus with a free vascularised bone graft from the medial condyle of the femur.

    PubMed

    Hintermann, B; Wagener, J; Knupp, M; Schweizer, C; J Schaefer, D

    2015-09-01

    Large osteochondral lesions (OCLs) of the shoulder of the talus cannot always be treated by traditional osteochondral autograft techniques because of their size, articular geometry and loss of an articular buttress. We hypothesised that they could be treated by transplantation of a vascularised corticoperiosteal graft from the ipsilateral medial femoral condyle. Between 2004 and 2011, we carried out a prospective study of a consecutive series of 14 patients (five women, nine men; mean age 34.8 years, 20 to 54) who were treated for an OCL with a vascularised bone graft. Clinical outcome was assessed using a visual analogue scale (VAS) for pain and the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score. Radiological follow-up used plain radiographs and CT scans to assess graft incorporation and joint deterioration. At a mean follow-up of 4.1 years (2 to 7), the mean VAS for pain had decreased from 5.8 (5 to 8) to 1.8 (0 to 4) (p = 0.001) and the mean AOFAS hindfoot score had increased from 65 (41 to 70) to 81 (54 to 92) (p = 0.003). Radiologically, the talar contour had been successfully reconstructed with stable incorporation of the vascularised corticoperiosteal graft in all patients. Joint degeneration was only seen in one ankle. Treatment of a large OCL of the shoulder of the talus with a vascularised corticoperiosteal graft taken from the medial condyle of the femur was found to be a safe, reliable method of restoring the contour of the talus in the early to mid-term. PMID:26330592

  3. Hierarchical Structure of Articular Bone-Cartilage Interface and Its Potential Application for Osteochondral Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Bian, Weiguo; Qin, Lian; Li, Dichen; Wang, Jin; Jin, Zhongmin

    2010-09-01

    The artificial biodegradable osteochondral construct is one of mostly promising lifetime substitute in the joint replacement. And the complex hierarchical structure of natural joint is important in developing the osteochondral construct. However, the architecture features of the interface between cartilage and bone, in particular those at the micro-and nano-structural level, remain poorly understood. This paper investigates these structural data of the cartilage-bone interface by micro computerized tomography (μCT) and Scanning Electron Microscope (SEM). The result of μCT shows that important bone parameters and the density of articular cartilage are all related to the position in the hierarchical structure. The conjunctions of bone and cartilage were defined by SEM. All of the study results would be useful for the design of osteochondral construct further manufactured by nano-tech. A three-dimensional model with gradient porous structure is constructed in the environment of Pro/ENGINEERING software.

  4. Bioprinting of a mechanically enhanced three-dimensional dual cell-laden construct for osteochondral tissue engineering using a multi-head tissue/organ building system

    NASA Astrophysics Data System (ADS)

    Shim, Jin-Hyung; Lee, Jung-Seob; Kim, Jong Young; Cho, Dong-Woo

    2012-08-01

    The aim of this study was to build a mechanically enhanced three-dimensional (3D) bioprinted construct containing two different cell types for osteochondral tissue regeneration. Recently, the production of 3D cell-laden structures using various scaffold-free cell printing technologies has opened up new possibilities. However, ideal 3D complex tissues or organs have not yet been printed because gel-state hydrogels have been used as the principal material and are unable to maintain the desired 3D structure due to their poor mechanical strength. In this study, thermoplastic biomaterial polycaprolactone (PCL), which shows relatively high mechanical properties as compared with hydrogel, was used as a framework for enhancing the mechanical stability of the bioprinted construct. Two different alginate solutions were then infused into the previously prepared framework consisting of PCL to create the 3D construct for osteochondral printing. For this work, a multi-head tissue/organ building system (MtoBS), which was particularly designed to dispense thermoplastic biomaterial and hydrogel having completely different rheology properties, was newly developed and used to bioprint osteochondral tissue. It was confirmed that the line width, position and volume control of PCL and alginate solutions were adjustable in the MtoBS. Most importantly, dual cell-laden 3D constructs consisting of osteoblasts and chondrocytes were successfully fabricated. Further, the separately dispensed osteoblasts and chondrocytes not only retained their initial position and viability, but also proliferated up to 7 days after being dispensed.

  5. Simultaneous Osteoperiosteal Autologous Iliac Crest Graft and Lateral Meniscus Allograft Transplantation for Osteochondral Lesion with Bony Defect and Lateral Discoid Meniscus Tear.

    PubMed

    Lee, Dhong Won; Kim, Jin Goo; Ha, Jeong Ku; Kim, Woo Jong

    2016-06-01

    The optimal treatment for combined osteochondritis dissecans (OCD) with considerable bony defect of the lateral femoral condyle (LFC) and torn discoid lateral meniscus is unclear. We present a case of a 15-year-old female who was a gymnast and had a large OCD lesion in the LFC combined with deficiency of the lateral meniscus. The patient underwent the "one-step" technique of osteoperiosteal autologous iliac crest graft and lateral meniscus allograft transplantation after a failure of meniscectomy with repair at another hospital. Twenty-four months postoperatively, clinical results were significantly improved. Follow-up imaging tests and second-look arthroscopy showed well incorporated structured bone graft and fibrous cartilage regeneration as well as stabilized lateral meniscus allograft. She could return to her sport without any pain or swelling. This "one-step" surgical technique is worth considering as a joint salvage procedure for massive OCD lesions with torn discoid lateral meniscus. PMID:27274475

  6. Simultaneous Osteoperiosteal Autologous Iliac Crest Graft and Lateral Meniscus Allograft Transplantation for Osteochondral Lesion with Bony Defect and Lateral Discoid Meniscus Tear

    PubMed Central

    Lee, Dhong Won; Ha, Jeong Ku; Kim, Woo Jong

    2016-01-01

    The optimal treatment for combined osteochondritis dissecans (OCD) with considerable bony defect of the lateral femoral condyle (LFC) and torn discoid lateral meniscus is unclear. We present a case of a 15-year-old female who was a gymnast and had a large OCD lesion in the LFC combined with deficiency of the lateral meniscus. The patient underwent the "one-step" technique of osteoperiosteal autologous iliac crest graft and lateral meniscus allograft transplantation after a failure of meniscectomy with repair at another hospital. Twenty-four months postoperatively, clinical results were significantly improved. Follow-up imaging tests and second-look arthroscopy showed well incorporated structured bone graft and fibrous cartilage regeneration as well as stabilized lateral meniscus allograft. She could return to her sport without any pain or swelling. This "one-step" surgical technique is worth considering as a joint salvage procedure for massive OCD lesions with torn discoid lateral meniscus. PMID:27274475

  7. [Tissue grafts: an activity concerning many patients].

    PubMed

    Loty, B

    1997-11-15

    Tissue allografts mainly include corneas, bone (and cartilage, tendon, ligament, aponevrosis), skin, vessels and cardiac valves. All these grafts have been widely used for many years and were the subject of a large number of experimental and clinical studies. The different steps allowing the obtention of different tissue allografts have in fact a common organization through tissue procurement and banking activities. Tissue banks have a central situation ensuring security, safety, traceability and distribution of tissues. Appropriate organization of the banks, and respect of high level standards are thus mandatory. Tissue transplantation activity in France has been studied through national surveys: they concern more than 600 hospitals and clinics, and grafts procured in France (excluding imported allografts) are around 15,000 a year. Precise regulation implied by the bioethical law published in 1994 and homogeneous organization of the activity allow the use of stringent and regularly updated standards, allowing the distribution to the patients of safe grafts procured in ethical conditions. The actual shortage of tissue allografts in France implies increasing procurement through a better organization of retrieval in hospitals and clinics and donation promotion. PMID:9501596

  8. CHONDROCYTE VIABILITY IS HIGHER AFTER PROLONGED STORAGE AT 37°C THAN AT 4°C FOR OSTEOCHONDRAL GRAFTS

    PubMed Central

    Pallante, Andrea L.; Bae, Won C.; Chen, Albert C.; Görtz, Simon; Bugbee, William D.; Sah, Robert L.

    2010-01-01

    Background Osteochondral allografts are currently stored at 4°C for 2–6 weeks before implantation. At 4°C, chondrocyte viability, especially in the superficial zone, deteriorates starting at 2 weeks. Alternative storage conditions could maintain chondrocyte viability beyond 2 weeks, and thereby facilitate increased graft availability and enhanced graft quality. Purpose Determine effects of prolonged 37°C storage compared to traditional 4°C storage on chondrocyte viability and cartilage matrix content. Study Design Controlled Laboratory Study Methods Osteochondral samples from humeral heads of adult goats were analyzed (i) fresh, or after storage in medium for (ii) 14d at 4°C including 10% FBS, (iii) 28d at 4°C including 10% FBS, (iv) 28d at 37°C without FBS, (v) 28d at 37°C including 2% FBS, or (vi) 28d at 37°C including 10% FBS. Portions of samples were analyzed by microscopy after LIVE/DEAD® staining to determine chondrocyte viability and density, both en face (to visualize the articular surface) and vertically (overall and in superficial, middle, and deep zones). The remaining cartilage was analyzed for sulfated-glycosaminoglycan and collagen. Results 37°C storage maintained high chondrocyte viability compared to 4°C storage. Viability of samples after 28d at 37°C was ~80% at the cartilage surface en face, ~65% in the superficial zone, and ~70% in the middle zone, which was much higher than ~45%, ~20%, and ~35%, respectively, in 4°C samples after 28d, and slightly decreased from ~100%, ~85%, and ~95%, respectively, in fresh controls. Cartilage thickness, glycosaminoglycan content, and collagen content were maintained for 37°C and 4°C samples compared to fresh controls. Conclusion 37°C storage of osteochondral grafts supports long-term chondrocyte viability, especially at the vulnerable surface and superficial zone of cartilage. Clinical Relevance Storage of allografts at physiological temperature of 37°C may prolong storage duration, improve

  9. Hyaluronic Acid (800 kDa) Supplementation of University of Wisconsin Solution Improves Viability of Osteochondral Grafts and Reduces Matrix Metalloproteinase Expression during Cold Preservation

    PubMed Central

    Yamada, Takuya; Uchida, Kentaro; Onuma, Kenji; Inoue, Gen; Aikawa, Jun; Takano, Shotaro; Sekiguchi, Hiroyuki; Fujimaki, Hisako; Miyagi, Masayuki; Takaso, Masashi

    2015-01-01

    Osteochondral allografting is a promising option for the treatment of large cartilage defects. However, because the cell viability of osteochondral tissues (OCTs) gradually reduces during storage at 4°C, methods for maintaining the cell viability of fresh OCTs are needed to improve transplantation outcomes. Here, we evaluated whether the supplementation of preservation solution with one of three different molecular weight forms of hyaluronic acid (HA) improved the viability of rat OCTs during long-term cold storage. The supplementation of University of Wisconsin (UW) solution with 800 kDa significantly improved the cell viability of OCT after 14 days at 4°C compared to nonsupplemented UW solution. In contrast, UW solution supplemented with either 1900 or 6000 kDa HA did not markedly improve the cell viability of the OCT. Real-time PCR analysis revealed that the levels of matrix metalloproteinases 2, 3, and 9 were significantly decreased in OCT stored in UW solution supplemented with 800 kDa HA. Although further studies in human OCT are warranted, these findings demonstrate that the use of 800 kDa HA in place of serum may be a suitable approach for the long-term preservation of osteochondral allografts designated for the repair of large cartilage defects in the clinical setting. PMID:26199955

  10. Tissue engineered small-diameter vascular grafts.

    PubMed

    Schmedlen, Rachael H; Elbjeirami, Wafa M; Gobin, Andrea S; West, Jennifer L

    2003-10-01

    Arterial occlusive disease remains the leading cause of death in western countries and often requires vascular reconstructive surgery. The limited supply of suitable small-diameter vascular grafts has led to the development of tissue engineered blood vessel substitutes. Many different approaches have been examined, including natural scaffolds containing one or more ECM proteins and degradable polymeric scaffolds. For optimal graft development, many efforts have modified the culture environment to enhance ECM synthesis and organization using bioreactors under physiologic conditions and biochemical supplements. In the past couple of decades, a great deal of progress on TEVGs has been made. Many challenges remain and are being addressed, particularly with regard to the prevention of thrombosis and the improvement of graft mechanical properties. To develop a patent TEVG that grossly resembles native tissue, required culture times in most studies exceed 8 weeks. Even with further advances in the field, TEVGs will likely not be used in emergency situations because of the time necessary to allow for cell expansion, ECM production and organization, and attainment of desired mechanical strength. Furthermore, TEVGs will probably require the use of autologous tissue to prevent an immunogenic response, unless advances in immune acceptance render allogenic and xenogenic tissue use feasible. TEVGs have not yet been subjected to clinical trials, which will determine the efficacy of such grafts in the long term. Finally, off-the-shelf availability and cost will become the biggest hurdles in the development of a feasible TEVG product. Although many obstacles exist in the effort to develop a small-diameter TEVG, the potential benefits of such an achievement are exciting. In the near future, a nonthrombogenic TEVG with sufficient mechanical strength may be developed for clinical trials. Such a graft will have the minimum characteristics of biological tissue necessary to remain patent

  11. Repair of osteochondral defects by mosaicplasty and allogeneic BMSCs transplantation

    PubMed Central

    Ma, Xin; Sun, Yuan; Cheng, Xiangguo; Gao, Youshui; Hu, Bin; Wen, Gen; Qian, Yebin; Gu, Wenqi; Mao, Yanjie; Liu, Wanjun

    2015-01-01

    Objective: To investigate the feasibility and efficacy of repairing osteochondral defects with mosaicplasty and allogeneic bone marrow mesenchymal stem cells (BMSCs) transplantation. Methods: BMSCs were harvested from rabbits and maintained in vitro. Cells of third passage were mixed with pluronic F-127. Osteochondral defect animal model was established in rabbits and then this defect was treated with autologous osteochondral grafts with or without BMSCs above mentioned. In control group, pure pluronic F-127 was filled in the defect. Histological and immunohistological examinations were performed for the evaluation of therapeutic effectiveness. Results: Autologous osteochondral grafts in both groups were not loose, prolapsed and depressed. In BMSCs group, the tissues in the “death space” became hyaline cartilage. The arrangement of chondrocytes was regular. At 4, 8, 12 and 16 weeks, O’Driscoll and Keeley and Salter score were 14.00±1.00, 16.75±1.71, 18.00±0.82 and 20.50±1.29 in BMSCs group, which were significantly higher than those in control group (7.67±0.58, 8.00±0.82, 8.50±0.58 and 9.00±0.82, respectively). There were significant differences among different treatments (F=584.028, P=0.000), but the score was comparable between right defect and left defect (F=0.028, P=0.890). In addition, significant difference was also observed at different time points (F=18.364, P=0.000), but there was no interaction between time and treatment (F=6.939, P=0.015). Moreover, interactions among other factors were also not observed. Conclusion: Mosaicplasty and BMSC transplantation are effective to repair the osteochondral defects and integrate the “death space”, achieving a better therapeutic efficacy. Thus, this combined therapy may become an effective strategy for the therapy of osteochondral defects. PMID:26131203

  12. A Silk Fibroin and Peptide Amphiphile-Based Co-Culture Model for Osteochondral Tissue Engineering.

    PubMed

    Çakmak, Soner; Çakmak, Anıl S; Kaplan, David L; Gümüşderelioğlu, Menemşe

    2016-08-01

    New biomaterials with the properties of both bone and cartilage extracellular matrices (ECM) should be designed and used with co-culture systems to address clinically applicable osteochondral constructs. Herein, a co-culture model is described based on a trilayered silk fibroin-peptide amphiphile (PA) scaffold cultured with human articular chondrocytes (hACs) and human bone marrow mesenchymal stem cells (hBMSCs) in an osteochondral cocktail medium for the cartilage and bone sides, respectively. The presence of hACs in the co-cultures significantly increases the osteogenic differentiation potential of hBMSCs based on ALP activity, RT-PCR for osteogenic markers, calcium analyses, and histological stainings, whereas hACs produces a significant amount of glycosaminoglycans (GAGs) for the cartilage region, even in the absence of growth factor TGF-β family in the co-culture medium. This trilayered scaffold with trophic effects offers a promising strategy for the study of osteochondral defects. PMID:27139244

  13. Treatment of osteochondral defects in the rabbit's knee joint by implantation of allogeneic mesenchymal stem cells in fibrin clots.

    PubMed

    Berninger, Markus T; Wexel, Gabriele; Rummeny, Ernst J; Imhoff, Andreas B; Anton, Martina; Henning, Tobias D; Vogt, Stephan

    2013-01-01

    The treatment of osteochondral articular defects has been challenging physicians for many years. The better understanding of interactions of articular cartilage and subchondral bone in recent years led to increased attention to restoration of the entire osteochondral unit. In comparison to chondral lesions the regeneration of osteochondral defects is much more complex and a far greater surgical and therapeutic challenge. The damaged tissue does not only include the superficial cartilage layer but also the subchondral bone. For deep, osteochondral damage, as it occurs for example with osteochondrosis dissecans, the full thickness of the defect needs to be replaced to restore the joint surface (1). Eligible therapeutic procedures have to consider these two different tissues with their different intrinsic healing potential (2). In the last decades, several surgical treatment options have emerged and have already been clinically established (3-6). Autologous or allogeneic osteochondral transplants consist of articular cartilage and subchondral bone and allow the replacement of the entire osteochondral unit. The defects are filled with cylindrical osteochondral grafts that aim to provide a congruent hyaline cartilage covered surface (3,7,8). Disadvantages are the limited amount of available grafts, donor site morbidity (for autologous transplants) and the incongruence of the surface; thereby the application of this method is especially limited for large defects. New approaches in the field of tissue engineering opened up promising possibilities for regenerative osteochondral therapy. The implantation of autologous chondrocytes marked the first cell based biological approach for the treatment of full-thickness cartilage lesions and is now worldwide established with good clinical results even 10 to 20 years after implantation (9,10). However, to date, this technique is not suitable for the treatment of all types of lesions such as deep defects involving the subchondral

  14. Soft Tissue Augmentation with Silk Composite Graft

    PubMed Central

    Park, Yong-Tae; Kweon, Hae Yong; Kim, Seong-Gon

    2014-01-01

    Purpose: The objective of this study was to evaluate the interaction between 4-hexylresorcinol (4HR) and antibody as that affects the performance of a silk-4HR combination graft for soft tissue augmentation in an animal model. Methods: The silk graft materials consisted of four types: silk+10% tricalcium phosphate (TCP) (ST0), silk+10% TCP+1% 4HR (ST1), silk+10% TCP+3% 4HR (ST3), and silk+10% TCP+6% 4-HR (ST6). The antibody binding assay tested the 4HR effect and scanning electron microscopic (SEM) exam was done for silk grafts. The animal experiment used a subcutaneous pocket mouse model. The graft – SH0 or SH1 or SH3 or SH6 – was placed in a subcutaneous pocket. The animals were killed at one, two, and four weeks, postoperatively. The specimens were subjected to histological analysis and lysozyme assay. Results: Groups with 4HR applied showed lower antibody binding affinity to antigen compared to groups without 4HR. In the SEM examination, there was no significant difference among groups. Histological examinations revealed many foreign body giant cells in ST0 and ST1 group at four weeks postoperatively. Both ST3 and ST6 groups developed significantly lower levels of giant cell values compared to ST0 and ST1 groups (P <0.001) at four weeks postoperatively. In the lysozyme assay, the ST1 and ST3 groups showed denser signals than the other groups. Conclusion: 4HR combined silk implants resulted in high levels of vascular and connective tissue regeneration. PMID:27489833

  15. Specific inductive potential of a novel nanocomposite biomimetic biomaterial for osteochondral tissue regeneration.

    PubMed

    Manferdini, C; Cavallo, C; Grigolo, B; Fiorini, M; Nicoletti, A; Gabusi, E; Zini, N; Pressato, D; Facchini, A; Lisignoli, G

    2016-05-01

    Osteochondral lesions require treatment to restore the biology and functionality of the joint. A novel nanostructured biomimetic gradient scaffold was developed to mimic the biochemical and biophysical properties of the different layers of native osteochondral structure. The present results show that the scaffold presents important physicochemical characteristics and can support the growth and differentiation of mesenchymal stromal cells (h-MSCs), which adhere and penetrate into the cartilaginous and bony layers. H-MSCs grown in chondrogenic or osteogenic medium decreased their proliferation during days 14-52 on both scaffold layers and in medium without inducing factors used as controls. Both chondrogenic and osteogenic differentiation of h-MSCs occurred from day 28 and were increased on day 52, but not in the control medium. Safranin O staining and collagen type II and proteoglycans immunostaining confirmed that chondrogenic differentiation was specifically induced only in the cartilaginous layer. Conversely, von Kossa staining, osteocalcin and osteopontin immunostaining confirmed that osteogenic differentiation occurred on both layers. This study shows the specific potential of each layer of the biomimetic scaffold to induce chondrogenic or osteogenic differentiation of h-MSCs. These processes depended mainly on the media used but not the biomaterial itself, suggesting that the local milieu is fundamental for guiding cell differentiation. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23495253

  16. Biomaterials/scaffolds. Design of bioactive, multiphasic PCL/collagen type I and type II-PCL-TCP/collagen composite scaffolds for functional tissue engineering of osteochondral repair tissue by using electrospinning and FDM techniques.

    PubMed

    Schumann, Detlef; Ekaputra, Andrew K; Lam, Christopher X F; Hutmacher, Dietmar W

    2007-01-01

    Current clinical therapies for traumatic or chronic injuries involving osteochondral tissue result in temporary pain reduction and filling of the defect but with biomechanically inferior repair tissue. Tissue engineering of osteochondral repair tissue using autologous cells and bioactive biomaterials has the potential to overcome the current limitations and results in native-like repair tissue with good integration capabilities. For this reason, we applied two modem biomaterial design techniques, namely, electrospinning and fused deposition modeling (FDM), to produce bioactive poly(epsilon-caprolactone)/collagen (PCL/Col) type I and type II-PCL-tri-calcium phosphate (TCP)/Col composites for precursor cell-based osteochondral repair. The application of these two design techniques (electrospinning and FDM) allowed us to specifically produce the a suitable three-dimensional (3D) environment for the cells to grow into a particular tissue (cartilage and bone) in vitro prior to in vivo implantation. We hypothesize that our new designed biomaterials, seeded with autologous bone marrow-derived precursor cells, in combination with bioreactor-stimulated cell-culture techniques can be used to produce clinically relevant osteochondral repair tissue. PMID:18085205

  17. Biomimetic biphasic scaffolds for osteochondral defect repair

    PubMed Central

    Li, Xuezhou; Ding, Jianxun; Wang, Jincheng; Zhuang, Xiuli; Chen, Xuesi

    2015-01-01

    The osteochondral defects caused by vigorous trauma or physical disease are difficult to be managed. Tissue engineering provides a possible option to regenerate the damaged osteochondral tissues. For osteochondral reconstruction, one intact scaffold should be considered to support the regeneration of both cartilage and subchondral bone. Therefore, the biphasic scaffolds with the mimic structures of osteochondral tissues have been developed to close this chasm. A variety of biomimetic bilayer scaffolds fabricated from natural or synthetic polymers, or the ones loading with growth factors, cells, or both of them make great progresses in osteochondral defect repair. In this review, the preparation and in vitro and/or in vivo verification of bioinspired biphasic scaffolds are summarized and discussed, as well as the prospect is predicted. PMID:26816644

  18. [Tissue engineering applied to the trachea as a graft].

    PubMed

    Barrera-Ramírez, Elisa; Rico-Escobar, Edna; Garrido-Cardona, Rubén E

    2016-01-01

    Tissue engineering offers, through new technologies, an ex vivo generation of organs and functional tissues as grafts for transplants, for the improvement and substitution of biological functions, with an absence of immunological response. The treatment of extended tracheal lesions is a substitution of the affected segment; nevertheless, the allogeneic transplant has failed and the use of synthetic materials has not had good results. New tissue engineering technology is being developed to offer a tracheal graft for a posterior implantation. The purpose of this article is to review all the methods and components used by the engineering of tissue for tracheal grafts. PMID:26927653

  19. Cell-free multi-layered collagen-based scaffolds demonstrate layer specific regeneration of functional osteochondral tissue in caprine joints.

    PubMed

    Levingstone, Tanya J; Ramesh, Ashwanth; Brady, Robert T; Brama, Pieter A J; Kearney, Clodagh; Gleeson, John P; O'Brien, Fergal J

    2016-05-01

    Developing repair strategies for osteochondral tissue presents complex challenges due to its interfacial nature and complex zonal structure, consisting of subchondral bone, intermediate calcified cartilage and the superficial cartilage regions. In this study, the long term ability of a multi-layered biomimetic collagen-based scaffold to repair osteochondral defects is investigated in a large animal model: namely critical sized lateral trochlear ridge (TR) and medial femoral condyle (MC) defects in the caprine stifle joint. The study thus presents the first data in a clinically applicable large animal model. Scaffold fixation and early integration was demonstrated at 2 weeks post implantation. Macroscopic analysis demonstrated improved healing in the multi-layered scaffold group compared to empty defects and a market approved synthetic polymer osteochondral scaffold groups at 6 and 12 months post implantation. Radiological analysis demonstrated superior subchondral bone formation in both defect sites in the multi-layered scaffold group as early as 3 months, with complete regeneration of subchondral bone by 12 months. Histological analysis confirmed the formation of well-structured subchondral trabecular bone and hyaline-like cartilage tissue in the multi-layered scaffold group by 12 months with restoration of the anatomical tidemark. Demonstration of improved healing following treatment with this natural polymer scaffold, through the recruitment of host cells with no requirement for pre-culture, shows the potential of this device for the treatment of patients presenting with osteochondal lesions. PMID:26901430

  20. TISSUE GRAFTS IN VITILIGO SURGERY – PAST, PRESENT, AND FUTURE

    PubMed Central

    Khunger, Niti; Kathuria, Sushruta Dash; Ramesh, V.

    2009-01-01

    Vitiligo, characterized by depigmented macules is a common disorder with a high psychosocial impact, particularly in darker skins. Surgical methods become important in cases where medical therapy fails to cause repigmentation or in cases of segmental vitiligo where the response to surgery is excellent. The basic principle of surgical treatment is autologous grafting of viable melanocytes from pigmented donor skin to recipient vitiliginous areas. Various grafting methods have been described including tissue grafts and cellular grafts. Stability of the disease is the most important criterion to obtain a successful outcome. Counseling of the patient regarding the outcome is vital before surgery. The technique and followup management of the tissue grafts has been described in detail in this review. PMID:20101311

  1. Platelet-rich plasma increases transforming growth factor-beta1 expression at graft-host interface following autologous osteochondral transplantation in a rabbit model

    PubMed Central

    Boakye, Lorraine A; Ross, Keir A; Pinski, John M; Smyth, Niall A; Haleem, Amgad M; Hannon, Charles P; Fortier, Lisa A; Kennedy, John G

    2015-01-01

    AIM: To explore the effect of platelet-rich plasma on protein expression patterns of transforming growth factor-beta1 (TGF-β1) in cartilage following autologous osteochondral transplantation (AOT) in a rabbit knee cartilage defect model. METHODS: Twelve New Zealand white rabbits received bilateral AOT. In each rabbit, one knee was randomized to receive an autologous platelet rich plasma (PRP) injection and the contralateral knee received saline injection. Rabbits were euthanized at 3, 6 and 12 wk post-operatively. Articular cartilage sections were stained with TGF-β1 antibody. Histological regions of interest (ROI) (left, right and center of the autologous grafts interfaces) were evaluated using MetaMorph. Percentage of chondrocytes positive for TGF-β1 was then assessed. RESULTS: Percentage of chondrocytes positive for TGF-β1 was higher in PRP treated knees for selected ROIs (left; P = 0.03, center; P = 0.05) compared to control and was also higher in the PRP group at each post-operative time point (P = 6.6 × 10-4, 3.1 × 10-4 and 7.3 × 10-3 for 3, 6 and 12 wk, respectively). TGF-β1 expression was higher in chondrocytes of PRP-treated knees (36% ± 29% vs 15% ± 18%) (P = 1.8 × 10-6) overall for each post-operative time point and ROI. CONCLUSION: Articular cartilage of rabbits treated with AOT and PRP exhibit increased TGF-β1 expression compared to those treated with AOT and saline. Our findings suggest that adjunctive PRP may increase TGF-β1 expression, which may play a role in the chondrogenic effect of PRP in vivo. PMID:26716092

  2. Tissue-engineered lymphatic graft for the treatment of lymphedema

    PubMed Central

    Kanapathy, Muholan; Patel, Nikhil M.; Kalaskar, Deepak M.; Mosahebi, Afshin; Mehrara, Babak J.; Seifalian, Alexander M.

    2015-01-01

    Background Lymphedema is a chronic debilitating condition and curative treatment is yet to be found. Tissue engineering approach, which combines cellular components, scaffold, and molecular signals hold great potential in the treatment of secondary lymphedema with the advent of lymphatic graft to reconstruct damaged collecting lymphatic vessel. This review highlights the ideal characteristics of lymphatic graft, the limitation and challenges faced, and the approaches in developing tissue-engineered lymphatic graft. Methods Literature on tissue engineering of lymphatic system and lymphatic tissue biology was reviewed. Results The prime challenge in the design and manufacturing of this graft is producing endothelialized conduit with intraluminal valves. Suitable scaffold material is needed to ensure stability and functionality of the construct. Endothelialization of the construct can be enhanced via biofunctionalization and nanotopography, which mimics extracellular matrix. Nanocomposite polymers with improved performance over existing biomaterials are likely to benefit the development of lymphatic graft. Conclusions With the in-depth understanding of tissue engineering, nanotechnology, and improved knowledge on the biology of lymphatic regeneration, the aspiration to develop successful lymphatic graft is well achievable. PMID:25248852

  3. Three-dimensional bioprinting of multilayered constructs containing human mesenchymal stromal cells for osteochondral tissue regeneration in the rabbit knee joint.

    PubMed

    Shim, Jin-Hyung; Jang, Ki-Mo; Hahn, Sei Kwang; Park, Ju Young; Jung, Hyuntae; Oh, Kyunghoon; Park, Kyeng Min; Yeom, Junseok; Park, Sun Hwa; Kim, Sung Won; Wang, Joon Ho; Kim, Kimoon; Cho, Dong-Woo

    2016-03-01

    The use of cell-rich hydrogels for three-dimensional (3D) cell culture has shown great potential for a variety of biomedical applications. However, the fabrication of appropriate constructs has been challenging. In this study, we describe a 3D printing process for the preparation of a multilayered 3D construct containing human mesenchymal stromal cells with a hydrogel comprised of atelocollagen and supramolecular hyaluronic acid (HA). This construct showed outstanding regenerative ability for the reconstruction of an osteochondral tissue in the knee joints of rabbits. We found that the use of a mechanically stable, host-guest chemistry-based hydrogel was essential and allowed two different types of extracellular matrix (ECM) hydrogels to be easily printed and stacked into one multilayered construct without requiring the use of potentially harmful chemical reagents or physical stimuli for post-crosslinking. To the best of our knowledge, this is the first study to validate the potential of a 3D printed multilayered construct consisting of two different ECM materials (atelocollagen and HA) for heterogeneous tissue regeneration using an in vivo animal model. We believe that this 3D printing-based platform technology can be effectively exploited for regeneration of various heterogeneous tissues as well as osteochondral tissue. PMID:26844597

  4. Inorganic-organic hybrid scaffolds for osteochondral regeneration.

    PubMed

    Munoz-Pinto, Dany J; McMahon, Rebecca E; Kanzelberger, Melissa A; Jimenez-Vergara, Andrea C; Grunlan, Melissa A; Hahn, Mariah S

    2010-07-01

    Ligament graft failure frequently results from poor integration of the replacement tissue with associated bone. Thus, the ability to regenerate the bone-ligament osteochondral interface would be advantageous in ligament reconstruction. At the osteochondral interface, the tissue transitions from a bone-like matrix to fibrocartilage. Therefore, a scaffold which promotes a spatially regulated transition in cell behavior from osteoblast-like to chondrocyte-like would be desirable. Previous research indicates that addition of inorganic components to organic scaffolds can enhance the deposition of bone-like matrix by associated osteoblasts. We therefore reasoned that a gradient in the inorganic content of a hybrid inorganic-organic scaffold may induce an osteochondral-like transition in cell phenotype and matrix production. To test this hypothesis, hydrogels were prepared from poly(ethylene glycol) (PEG) and star poly(dimethylsiloxane) (PDMS(star)). As anticipated, both the matrix deposition and phenotype of encapsulated osteoblasts varied with scaffold inorganic content, although the directionality of this modulation was contrary to expectation. Specifically, osteoblasts appeared to transdifferentiate into chondrocyte-like cells with increasing scaffold inorganic content, as indicated by increased chondroitin sulfate and collagen type II production and by upregulation of sox9, a transcription factor associated with chondrocytic differentiation. Furthermore, the deposition of bone-like matrix (collagen type I, calcium phosphate, and osteocalcin) decreased with increasing PDMS(star) content. The resistance of the PDMS(star)-PEG scaffolds to protein adsorption and/or the changes in gel modulus/mesh structure accompanying PDMS(star) incorporation may underlie the unexpected increase in chondrocytic phenotype with increasing inorganic content. Combined, the present results indicate that PDMS(star)-PEG hybrid gels may prove promising for osteochondral regeneration. (c) 2010

  5. Decellularized Cartilage May Be a Chondroinductive Material for Osteochondral Tissue Engineering

    PubMed Central

    Sutherland, Amanda J.; Beck, Emily C.; Dennis, S. Connor; Converse, Gabriel L.; Hopkins, Richard A.; Berkland, Cory J.; Detamore, Michael S.

    2015-01-01

    Extracellular matrix (ECM)-based materials are attractive for regenerative medicine in their ability to potentially aid in stem cell recruitment, infiltration, and differentiation without added biological factors. In musculoskeletal tissue engineering, demineralized bone matrix is widely used, but recently cartilage matrix has been attracting attention as a potentially chondroinductive material. The aim of this study was thus to establish a chemical decellularization method for use with articular cartilage to quantify removal of cells and analyze the cartilage biochemical content at various stages during the decellularization process, which included a physically devitalization step. To study the cellular response to the cartilage matrix, rat bone marrow-derived mesenchymal stem cells (rBMSCs) were cultured in cell pellets containing cells only (control), chondrogenic differentiation medium (TGF-β), chemically decellularized cartilage particles (DCC), or physically devitalized cartilage particles (DVC). The chemical decellularization process removed the vast majority of DNA and about half of the glycosaminoglycans (GAG) within the matrix, but had no significant effect on the amount of hydroxyproline. Most notably, the DCC group significantly outperformed TGF-β in chondroinduction of rBMSCs, with collagen II gene expression an order of magnitude or more higher. While DVC did not exhibit a chondrogenic response to the extent that DCC did, DVC had a greater down regulation of collagen I, collagen X and Runx2. A new protocol has been introduced for cartilage devitalization and decellularization in the current study, with evidence of chondroinductivity. Such bioactivity along with providing the ‘raw material’ building blocks of regenerating cartilage may suggest a promising role for DCC in biomaterials that rely on recruiting endogenous cell recruitment and differentiation for cartilage regeneration. PMID:25965981

  6. Controlled Release Strategies for Bone, Cartilage, and Osteochondral Engineering—Part I: Recapitulation of Native Tissue Healing and Variables for the Design of Delivery Systems

    PubMed Central

    Santo, Vítor E.; Mano, João F.; Reis, Rui L.

    2013-01-01

    The potential of growth factors to stimulate tissue healing through the enhancement of cell proliferation, migration, and differentiation is undeniable. However, critical parameters on the design of adequate carriers, such as uncontrolled spatiotemporal presence of bioactive factors, inadequate release profiles, and supraphysiological dosages of growth factors, have impaired the translation of these systems onto clinical practice. This review describes the healing cascades for bone, cartilage, and osteochondral interface, highlighting the role of specific growth factors for triggering the reactions leading to tissue regeneration. Critical criteria on the design of carriers for controlled release of bioactive factors are also reported, focusing on the need to provide a spatiotemporal control over the delivery and presentation of these molecules. PMID:23268651

  7. Optical methods for diagnostic of cell-tissue grafts

    NASA Astrophysics Data System (ADS)

    Timchenko, P. E.; Timchenko, E. V.; Volova, L. T.; Boltovskaya, V. V.; Zherdeva, L. A.; Belousov, N. V.; Pershutkina, S. V.

    2015-08-01

    In this work the results of cell-tissue grafts research with a complex of optical methods - confocal fluorescent microscopy and Raman spectroscopy are presented. It was established that coefficient M scatter is related to irregularity of demineralization process. It was microscopically shown that the quantity of integrated cells into these types of transplants amounts to 20% of its surface.

  8. Strategies for osteochondral repair: Focus on scaffolds

    PubMed Central

    Seo, Seog-Jin; Mahapatra, Chinmaya; Singh, Rajendra K; Knowles, Jonathan C

    2014-01-01

    Interest in osteochondral repair has been increasing with the growing number of sports-related injuries, accident traumas, and congenital diseases and disorders. Although therapeutic interventions are entering an advanced stage, current surgical procedures are still in their infancy. Unlike other tissues, the osteochondral zone shows a high level of gradient and interfacial tissue organization between bone and cartilage, and thus has unique characteristics related to the ability to resist mechanical compression and restoration. Among the possible therapies, tissue engineering of osteochondral tissues has shown considerable promise where multiple approaches of utilizing cells, scaffolds, and signaling molecules have been pursued. This review focuses particularly on the importance of scaffold design and its role in the success of osteochondral tissue engineering. Biphasic and gradient composition with proper pore configurations are the basic design consideration for scaffolds. Surface modification is an essential technique to improve the scaffold function associated with cell regulation or delivery of signaling molecules. The use of functional scaffolds with a controllable delivery strategy of multiple signaling molecules is also considered a promising therapeutic approach. In this review, we updated the recent advances in scaffolding approaches for osteochondral tissue engineering. PMID:25343021

  9. Extracellular Calcium Modulates Chondrogenic and Osteogenic Differentiation of Human Adipose-Derived Stem Cells: A Novel Approach for Osteochondral Tissue Engineering Using a Single Stem Cell Source

    PubMed Central

    Mellor, Liliana F.; Mohiti-Asli, Mahsa; Williams, John; Kannan, Arthi; Dent, Morgan R.; Guilak, Farshid

    2015-01-01

    We have previously shown that elevating extracellular calcium from a concentration of 1.8 to 8 mM accelerates and increases human adipose-derived stem cell (hASC) osteogenic differentiation and cell-mediated calcium accretion, even in the absence of any other soluble osteogenic factors in the culture medium. However, the effects of elevated calcium on hASC chondrogenic differentiation have not been reported. The goal of this study was to determine the effects of varied calcium concentrations on chondrogenic differentiation of hASC. We hypothesized that exposure to elevated extracellular calcium (8 mM concentration) in a chondrogenic differentiation medium (CDM) would inhibit chondrogenesis of hASC when compared to basal calcium (1.8 mM concentration) controls. We further hypothesized that a full osteochondral construct could be engineered by controlling local release of calcium to induce site-specific chondrogenesis and osteogenesis using only hASC as the cell source. Human ASC was cultured as micromass pellets in CDM containing transforming growth factor-β1 and bone morphogenetic protein 6 for 28 days at extracellular calcium concentrations of either 1.8 mM (basal) or 8 mM (elevated). Our findings indicated that elevated calcium induced osteogenesis and inhibited chondrogenesis in hASC. Based on these findings, stacked polylactic acid nanofibrous scaffolds containing either 0% or 20% tricalcium phosphate (TCP) nanoparticles were electrospun and tested for site-specific chondrogenesis and osteogenesis. Histological assays confirmed that human ASC differentiated locally to generate calcified tissue in layers containing 20% TCP, and cartilage in the layers with no TCP when cultured in CDM. This is the first study to report the effects of elevated calcium on chondrogenic differentiation of hASC, and to develop osteochondral nanofibrous scaffolds using a single cell source and controlled calcium release to induce site-specific differentiation. This approach

  10. Development of Small Diameter Nanofiber Tissue Engineered Arterial Grafts

    PubMed Central

    Tara, Shuhei; Rocco, Kevin A.; Bagi, Paul S.; Yi, Tai; Udelsman, Brooks; Zhuang, Zhen W.; Cleary, Muriel; Iwakiri, Yasuko; Breuer, Christopher K.; Shinoka, Toshiharu

    2015-01-01

    The surgical repair of heart and vascular disease often requires implanting synthetic grafts. While synthetic grafts have been successfully used for medium-to-large sized arteries, applications for small diameter arteries (<6 mm) is limited due to high rates of occlusion by thrombosis. Our objective was to develop a tissue engineered vascular graft (TEVG) for small diameter arteries. TEVGs composed of polylactic acid nanofibers with inner luminal diameter between 0.5 and 0.6 mm were surgically implanted as infra-renal aortic interposition conduits in 25 female C17SCID/bg mice. Twelve mice were given sham operations. Survival of mice with TEVG grafts was 91.6% at 12 months post-implantation (sham group: 83.3%). No instances of graft stenosis or aneurysmal dilatation were observed over 12 months post-implantation, assessed by Doppler ultrasound and microCT. Histologic analysis of explanted TEVG grafts showed presence of CD31-positive endothelial monolayer and F4/80-positive macrophages after 4, 8, and 12 months in vivo. Cells positive for α-smooth muscle actin were observed within TEVG, demonstrating presence of smooth muscle cells (SMCs). Neo-extracellular matrix consisting mostly of collagen types I and III were observed at 12 months post-implantation. PCR analysis supports histological observations. TEVG group showed significant increases in expressions of SMC marker, collagen-I and III, matrix metalloproteinases-2 and 9, and itgam (a macrophage marker), when compared to sham group. Overall, patency rates were excellent at 12 months after implantation, as structural integrity of these TEVG. Tissue analysis also demonstrated vessel remodeling by autologous cell. PMID:25830942

  11. Clinical Evaluation of Papilla Reconstruction Using Subepithelial Connective Tissue Graft

    PubMed Central

    Kaushik, Alka; PK, Pal; Chopra, Deepak; Chaurasia, Vishwajit Rampratap; Masamatti, Vinaykumar S; DK, Suresh; Babaji, Prashant

    2014-01-01

    Objective: The aesthetics of the patient can be improved by surgical reconstruction of interdental papilla by using an advanced papillary flap interposed with subepithelial connective tissue graft. Materials and Methods: A total of fifteen sites from ten patients having black triangles/papilla recession in the maxillary anterior region were selected and subjected to presurgical evaluation. The sites were treated with interposed subepithelial connective tissue graft placed under a coronally advance flap. The integrity of the papilla was maintained by moving the whole of gingivopapillary unit coronally. The various parameters were analysed at different intervals. Results: There was a mean decrease in the papilla presence index score and distance from contact point to gingival margin, but it was statistically not significant. Also, there is increase in the width of the keratinized gingiva which was statistically highly significant. Conclusion: Advanced papillary flap with interposed sub–epithelial connective tissue graft can offer predictable results for the reconstruction of interdental papilla. If papilla loss occurs solely due to soft-tissue damage, reconstructive techniques can completely restore it; but if due to periodontal disease involving bone loss, reconstruction is generally incomplete and multiple surgical procedures may be required. PMID:25386529

  12. Tissue-Engineered Autologous Grafts for Facial Bone Reconstruction

    PubMed Central

    Bhumiratana, Sarindr; Bernhard, Jonathan C.; Alfi, David M.; Yeager, Keith; Eton, Ryan E.; Bova, Jonathan; Shah, Forum; Gimble, Jeffrey M.; Lopez, Mandi J.; Eisig, Sidney B.; Vunjak-Novakovic, Gordana

    2016-01-01

    Facial deformities require precise reconstruction of the appearance and function of the original tissue. The current standard of care—the use of bone harvested from another region in the body—has major limitations, including pain and comorbidities associated with surgery. We have engineered one of the most geometrically complex facial bones by using autologous stromal/stem cells, without bone morphogenic proteins, using native bovine bone matrix and a perfusion bioreactor for the growth and transport of living grafts. The ramus-condyle unit (RCU), the most eminent load-bearing bone in the skull, was reconstructed using an image-guided personalized approach in skeletally mature Yucatan minipigs (human-scale preclinical model). We used clinically approved decellularized bovine trabecular bone as a scaffolding material, and crafted it into an anatomically correct shape using image-guided micromilling, to fit the defect. Autologous adipose-derived stromal/stem cells were seeded into the scaffold and cultured in perfusion for 3 weeks in a specialized bioreactor to form immature bone tissue. Six months after implantation, the engineered grafts maintained their anatomical structure, integrated with native tissues, and generated greater volume of new bone and greater vascular infiltration than either non-seeded anatomical scaffolds or untreated defects. This translational study demonstrates feasibility of facial bone reconstruction using autologous, anatomically shaped, living grafts formed in vitro, and presents a platform for personalized bone tissue engineering. PMID:27306665

  13. Tissue-engineered autologous grafts for facial bone reconstruction.

    PubMed

    Bhumiratana, Sarindr; Bernhard, Jonathan C; Alfi, David M; Yeager, Keith; Eton, Ryan E; Bova, Jonathan; Shah, Forum; Gimble, Jeffrey M; Lopez, Mandi J; Eisig, Sidney B; Vunjak-Novakovic, Gordana

    2016-06-15

    Facial deformities require precise reconstruction of the appearance and function of the original tissue. The current standard of care-the use of bone harvested from another region in the body-has major limitations, including pain and comorbidities associated with surgery. We have engineered one of the most geometrically complex facial bones by using autologous stromal/stem cells, native bovine bone matrix, and a perfusion bioreactor for the growth and transport of living grafts, without bone morphogenetic proteins. The ramus-condyle unit, the most eminent load-bearing bone in the skull, was reconstructed using an image-guided personalized approach in skeletally mature Yucatán minipigs (human-scale preclinical model). We used clinically approved decellularized bovine trabecular bone as a scaffolding material and crafted it into an anatomically correct shape using image-guided micromilling to fit the defect. Autologous adipose-derived stromal/stem cells were seeded into the scaffold and cultured in perfusion for 3 weeks in a specialized bioreactor to form immature bone tissue. Six months after implantation, the engineered grafts maintained their anatomical structure, integrated with native tissues, and generated greater volume of new bone and greater vascular infiltration than either nonseeded anatomical scaffolds or untreated defects. This translational study demonstrates feasibility of facial bone reconstruction using autologous, anatomically shaped, living grafts formed in vitro, and presents a platform for personalized bone tissue engineering. PMID:27306665

  14. Porous tantalum and poly-epsilon-caprolactone biocomposites for osteochondral defect repair: preliminary studies in rabbits.

    PubMed

    Mrosek, Eike H; Schagemann, Jan C; Chung, Hsi-Wei; Fitzsimmons, James S; Yaszemski, Michael J; Mardones, Rodrigo M; O'Driscoll, Shawn W; Reinholz, Gregory G

    2010-02-01

    Currently, various techniques are in use for the repair of osteochondral defects, none of them being truly satisfactory and they are often two step procedures. Comorbidity due to cancellous bone harvest from the iliac crest further complicates the procedure. Our previous in vitro studies suggest that porous tantalum (TM) or poly-epsilon-caprolactone scaffolds (PCL) in combination with periosteal grafts could be used for osteochondral defect repair. In this in vivo study, cylindrical osteochondral defects were created on the medial and lateral condyles of 10 rabbits and filled with TM/periosteum or PCL/periosteum biosynthetic composites (n = 8 each). The regenerated osteochondral tissue was then analyzed histologically, and evaluated in an independent and blinded manner by five different observers using a 30-point histological score. The overall histological score for PCL/periosteum was significantly better than for TM/periosteum. However, most of the regenerates were well integrated with the surrounding bone (PCL/periosteum, n = 6.4; TM/periosteum, n = 7) along with partial restoration of the tidemark (PCL/periosteum, n = 4.4; TM/periosteum, n = 5.6). A cover of hyaline-like morphology was found after PCL/periosteum treatment (n = 4.8), yet the cartilage yields were inconsistent. In conclusion, the applied TM and PCL scaffolds promoted excellent subchondral bone regeneration. Neo-cartilage formation from periosteum supported by a scaffold was inconsistent. This is the first study to show in vivo results of both PCL and TM scaffolds for a novel approach to osteochondral defect repair. PMID:19743507

  15. Electrospun Scaffolds for Tissue Engineering of Vascular Grafts

    PubMed Central

    Hasan, Anwarul; Memic, Adnan; Annabi, Nasim; Hossain, Monowar; Paul, Arghya; Dokmeci, Mehmet R.; Dehghani, Fariba; Khademhosseini, Ali

    2013-01-01

    There is a growing demand for off-the-shelf tissue engineered vascular grafts (TEVGs) for replacement or bypass of damaged arteries in various cardiovascular diseases. Scaffolds from the decellularized tissue skeletons to biopolymers and biodegradable synthetic polymers have been used for fabricating TEVGs. However, several issues have not yet been resolved, which include the inability to mimic the mechanical properties of native tissues, and the ability for long term patency and growth required for in vivo function. Electrospinning is a popular technique for the production of scaffolds that has the potential to address these issues. However, its application to human TEVGs has not yet been achieved. This review provides an overview of tubular scaffolds that have been prepared by electrospinning with potential for TEVG applications. PMID:23973391

  16. Synthesis of electroactive tetraaniline grafted polyethylenimine for tissue engineering

    NASA Astrophysics Data System (ADS)

    Dong, Shilei; Han, Lu; Cai, Muhang; Li, Luhai; Wei, Yan

    2015-07-01

    Tetraaniline grafted polyethylenimine (AT-PEI) was successfully synthesized in this study. Proton Nuclear Magnetic Resonance (1H NMR) Spectroscopy was used to determine the structure of carboxyl-capped aniline tetramer (AT-COOH) and AT-PEI. UV-Vis spectroscopy and Fourier transform infrared (FT-IR) spectroscopy were employed to characterize the absorption spectrum of the obtained AT-PEI samples. The morphology of AT-PEI copolymers in aqueous solution was determined by Scanning electron microscope (SEM). Moreover, AT-PEI copolymers demonstrated excellent solubility in aqueous solution and possessed electroactivity by cyclic voltammogram (CV) curves, which showed its potential application in the field of tissue engineering.

  17. 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

  18. Bilayered silk/silk-nanoCaP scaffolds for osteochondral tissue engineering: In vitro and in vivo assessment of biological performance.

    PubMed

    Yan, Le-Ping; Silva-Correia, Joana; Oliveira, Mariana B; Vilela, Carlos; Pereira, Hélder; Sousa, Rui A; Mano, João F; Oliveira, Ana L; Oliveira, Joaquim M; Reis, Rui L

    2015-01-01

    Novel porous bilayered scaffolds, fully integrating a silk fibroin (SF) layer and a silk-nano calcium phosphate (silk-nanoCaP) layer for osteochondral defect (OCD) regeneration, were developed. Homogeneous porosity distribution was achieved in the scaffolds, with calcium phosphate phase only retained in the silk-nanoCaP layer. The scaffold presented compressive moduli of 0.4MPa in the wet state. Rabbit bone marrow mesenchymal stromal cells (RBMSCs) were cultured on the scaffolds, and good adhesion and proliferation were observed. The silk-nanoCaP layer showed a higher alkaline phosphatase level than the silk layer in osteogenic conditions. Subcutaneous implantation in rabbits demonstrated weak inflammation. In a rabbit knee critical size OCD model, the scaffolds firmly integrated into the host tissue. Histological and immunohistochemical analysis showed that collagen II positive cartilage and glycosaminoglycan regeneration presented in the silk layer, and de novo bone ingrowths and vessel formation were observed in the silk-nanoCaP layer. These bilayered scaffolds can therefore be promising candidates for OCD regeneration. PMID:25449920

  19. Heparan Sulfate Proteoglycan Metabolism and the Fate of Grafted Tissues

    PubMed Central

    Wrenshall, Lucile E.; Johnson, Geoffrey B.; Cascalho, Marilia

    2016-01-01

    Tissue and organ transplants between genetically distinct individuals are always or nearly always rejected. The universality and speed of transplant rejection distinguishes this immune response from all others. Although this distinction is incompletely understood, some efforts to shed light on transplant rejection have revealed broader insights, including a relationship between activation of complement in grafted tissues, the metabolism of heparan sulfate proteoglycan and the nature of immune and inflammatory responses that ensue. Complement activation on cell surfaces, especially on endothelial cell surfaces, causes the shedding heparan sulfate, an acidic saccharide, from the cell surface and neighboring extracellular matrix. Solubilized in this way, heparan sulfate can activate leukocytes via toll like receptor-4, triggering inflammatory responses and activating dendritic cells, which migrate to regional lymphoid organs where they spark and to some extent govern cellular immune responses. In this way local ischemia, tissue injury and infection, exert systemic impact on immunity. Whether or in what circumstances this series of events explains the distinct characteristics of the immune response to transplants is still unclear but the events offer insight into the inception of immunity under the sub-optimal conditions accompanying infection and mechanisms by which infection and tissue injury engender systemic inflammation. PMID:26306447

  20. Nonlinear and Anisotropic Tensile Properties of Graft Materials used in Soft Tissue Applications

    PubMed Central

    Yoder, Jonathon H; Elliott, Dawn M

    2010-01-01

    Background The mechanical properties of extracellular matrix grafts that are intended to augment or replace soft tissues should be comparable to the native tissue. Such grafts are often used in fiber-reinforced tissue applications that undergo multi-axial loading and therefore knowledge of the anisotropic and nonlinear properties are needed, including the moduli and Poisson's ratio in two orthogonal directions within the plane of the graft. The objective of this study was to measure the tensile mechanical properties of several marketed grafts: Alloderm, Restore, CuffPatch, and OrthADAPT. Methods The degree of anisotropy and nonlinearity within each graft was evaluated from uniaxial tensile tests and compared to their native tissue. Results The Alloderm graft was anisotropic in both the toe and linear-region of the stress-strain response, was highly nonlinear, and generally had low properties. The Restore and CuffPatch grafts had similar stress-strain responses, were largely isotropic, had a linear-region modulus of 18 MPa, and were nonlinear. OrthADAPT was anisotropic in the linear region (131 vs 47 MPa) and was highly nonlinear. The Poisson ratio for all grafts was between 0.4 and 0.7, except for the parallel orientation of Restore which was greater than 1.0. Interpretation Having an informed understanding of how the available grafts perform mechanically will allow for better assessment by the physician for which graft to apply depending upon its application. PMID:20129728

  1. Establishing proof of concept: Platelet-rich plasma and bone marrow aspirate concentrate may improve cartilage repair following surgical treatment for osteochondral lesions of the talus

    PubMed Central

    Smyth, Niall A; Murawski, Christopher D; Haleem, Amgad M; Hannon, Charles P; Savage-Elliott, Ian; Kennedy, John G

    2012-01-01

    Osteochondral lesions of the talus are common injuries in the athletic patient. They present a challenging clinical problem as cartilage has a poor potential for healing. Current surgical treatments consist of reparative (microfracture) or replacement (autologous osteochondral graft) strategies and demonstrate good clinical outcomes at the short and medium term follow-up. Radiological findings and second-look arthroscopy however, indicate possible poor cartilage repair with evidence of fibrous infill and fissuring of the regenerative tissue following microfracture. Longer-term follow-up echoes these findings as it demonstrates a decline in clinical outcome. The nature of the cartilage repair that occurs for an osteochondral graft to become integrated with the native surround tissue is also of concern. Studies have shown evidence of poor cartilage integration, with chondrocyte death at the periphery of the graft, possibly causing cyst formation due to synovial fluid ingress. Biological adjuncts, in the form of platelet-rich plasma (PRP) and bone marrow aspirate concentrate (BMAC), have been investigated with regard to their potential in improving cartilage repair in both in vitro and in vitro settings. The in vitro literature indicates that these biological adjuncts may increase chondrocyte proliferation as well as synthetic capability, while limiting the catabolic effects of an inflammatory joint environment. These findings have been extrapolated to in vitro animal models, with results showing that both PRP and BMAC improve cartilage repair. The basic science literature therefore establishes the proof of concept that biological adjuncts may improve cartilage repair when used in conjunction with reparative and replacement treatment strategies for osteochondral lesions of the talus. PMID:22816065

  2. Point-of-care instrument for monitoring tissue health during skin graft repair

    NASA Astrophysics Data System (ADS)

    Gurjar, R. S.; Seetamraju, M.; Zhang, J.; Feinberg, S. E.; Wolf, D. E.

    2011-06-01

    We have developed the necessary theoretical framework and the basic instrumental design parameters to enable mapping of subsurface blood dynamics and tissue oxygenation for patients undergoing skin graft procedures. This analysis forms the basis for developing a simple patch geometry, which can be used to map by diffuse optical techniques blood flow velocity and tissue oxygenation as a function of depth in subsurface tissue.skin graft, diffuse correlation analysis, oxygen saturation.

  3. Material Properties of Fresh Cold-stored Allografts for Osteochondral Defects at 1 Year

    PubMed Central

    Ranawat, Anil S.; Vidal, Armando F.; Chen, Chris T.; Zelken, Jonathan A.; Turner, A. Simon

    2008-01-01

    Little is known about the long-term properties of fresh cold-stored osteochondral allograft tissue. We hypothesized fresh cold-stored tissue would yield superior material properties in an in vivo ovine model compared to those using freeze-thawed acellular grafts. In addition, we speculated that a long storage time would yield less successful grafts. We created 10-mm defects in medial femoral condyles of 20 sheep. Defects were reconstructed with allograft plugs stored at 4°C for 1, 14, and 42 days; control specimens were freeze-thawed or defect-only. At 52 weeks, animals were euthanized and retrieved grafts were analyzed for cell viability, gross morphology, histologic grade, and biomechanical and biochemical analysis. Explanted cold-stored tissue had superior histologic scores over freeze-thawed and defect-only grafts. Specimens stored for 1 and 42 days had higher equilibrium moduli and proteoglycan content than freeze-thawed specimens. We observed no difference among any of the cold-stored specimens for chondrocyte viability, histology, equilibrium aggregate modulus, proteoglycan content, or hypotonic swelling. Reconstructing cartilage defects with cold-stored allograft resulted in superior histologic and biomechanical properties compared with acellular freeze-thawed specimens; however, storage time did not appear to be a critical factor in the success of the transplanted allograft. PMID:18528743

  4. [Soft tissues volumes changing in malar and cheek area after fat grafting].

    PubMed

    Nadtochiy, A G; Grischenko, S V; Malitskaya, O A

    2016-01-01

    To improve the predictability of facial soft tissues fat grafting results tissue thickness dynamics before and 1 year postoperatively was assessed by means of ultrasonic method in 58 patients under standardized position of the ultrasonic transducer, physical and technical scanning conditions. The study revealed direct correlation of soft tissues thickness increase after fat grafting with the initial thickness of recipient area tissues. One year after fat grafting 60-65% of additional thickness remained in the lower regions of malar-cheek area (with the greatest soft tissues thickness), and only 25-27% preserved in the upper regions with the minimal initial thickness of soft tissues. I.e. to achieve necessary correction volume in a zone with small initial soft tissues thickness it is necessary to increase the amount of fat grafting stages. As the rates of soft tissues thickness in correction area change during 3-4 months after fat grafting remaining stable after this period it is expedient to assess postoperative results and to carry out repeated fat grafting not earlier than 4 months after operation. PMID:26925567

  5. Refixation of osteochondral fractures by ultrasound-activated, resorbable pins

    PubMed Central

    Neumann, H.; Schulz, A. P.; Gille, J.; Klinger, M.; Jürgens, C.; Reimers, N.; Kienast, B.

    2013-01-01

    Objectives Osteochondral injuries, if not treated adequately, often lead to severe osteoarthritis. Possible treatment options include refixation of the fragment or replacement therapies such as Pridie drilling, microfracture or osteochondral grafts, all of which have certain disadvantages. Only refixation of the fragment can produce a smooth and resilient joint surface. The aim of this study was the evaluation of an ultrasound-activated bioresorbable pin for the refixation of osteochondral fragments under physiological conditions. Methods In 16 Merino sheep, specific osteochondral fragments of the medial femoral condyle were produced and refixed with one of conventional bioresorbable pins, titanium screws or ultrasound-activated pins. Macro- and microscopic scoring was undertaken after three months. Results The healing ratio with ultrasound-activated pins was higher than with conventional pins. No negative heat effect on cartilage has been shown. Conclusion As the material is bioresorbable, no further surgery is required to remove the implant. MRI imaging is not compromised, as it is with implanted screws. The use of bioresorbable pins using ultrasound is a promising technology for the refixation of osteochondral fractures. PMID:23610699

  6. A new surgical technique to facilitate osteochondral autograft transfer in osteochondral defects of the capitellum: a case report.

    PubMed

    Bilsel, Kerem; Demirhan, Mehmet; Atalar, Ata Can; Akkaya, Semih

    2010-01-01

    A 17-year-old boy who was engaged in amateur weightlifting and body building presented with complaints of right elbow pain and limitation in elbow range of motion. Plain x-rays and magnetic resonance imaging showed an osteochondral defect in the medial third of the capitellum. At surgery, as a new technique, the lateral collateral ligament was detached from the humeral attachment to provide access to the capitellum with a clear and perpendicular exposure. Following removal of loose fragments within the joint, an osteochondral graft harvested from the lateral femoral condyle was implanted to the defect area of the capitellum. Postoperative radiologic controls showed that the defect was entirely filled by the graft with appropriate graft height. On follow-up examination at 12 months, the patient did not have any complaint about his elbow, and had no limitation of movement compared to the left elbow. Magnetic resonance imaging showed that the graft was successfully adapted to the recipient site without any sign of loosening. At final follow-up 40 months after surgery, the surface of the articular cartilage appeared normal. The range of elbow motion was preserved and the patient had no restriction in daily and sports activities. Considering technical difficulties posed by the narrow and complex structure of the elbow joint, this new technique involving detachment of the lateral collateral ligament facilitates perpendicular implantation of the graft. In our opinion, utilization of this new technique will improve functional and radiological results of osteochondral autograft transfer. PMID:20513997

  7. Evaluation of an injectable thermoresponsive hyaluronan hydrogel in a rabbit osteochondral defect model.

    PubMed

    D'Este, Matteo; Sprecher, Christoph Martin; Milz, Stefan; Nehrbass, Dirk; Dresing, Iska; Zeiter, Stephan; Alini, Mauro; Eglin, David

    2016-06-01

    Articular cartilage displays very little self-healing capabilities, generating a major clinical need. Here, we introduce a thermoresponsive hyaluronan hydrogel for cartilage repair obtained by covalently grafting poly(N-isopropylacrylamide) to hyaluronan, to give a brush co-polymer HpN. The gel is fluid at room temperature and becomes gel at body temperature. In this pilot study HpN safety and repair response were evaluated in an osteochondral defect model in rabbit. Follow-up was of 1 week and 12 weeks and the empty defect served as a control, for a total of four experimental groups. At 12 weeks the defect sites were evaluated macroscopically and histologically. Local lymph nodes, spleen, liver, and kidneys were analyzed for histopathological evaluation. HpN could be easily injected and remained into the defect throughout the study. The macroscopic score was statistically superior for HpN versus empty. Histological score gave opposite trend but not statistically significant. A slight tissue reaction was observed around HpN, however, vascularization and subchondral bone formation were not impeded. An upper proteoglycans rich fibro-cartilaginous tissue with fairly good continuity and lateral integration into the existing articular cartilage was observed in all cases. No signs of local or systemic acute or subacute toxicity were observed. In conclusion, HpN is easily injectable, remains into an osteochondral defect within a moving synovial joint, is biocompatible and does not interfere with the intrinsic healing response of osteochondral defects in a rabbit model. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1469-1478, 2016. PMID:26833870

  8. Layer-by-layer heparinization of decellularized liver matrices to reduce thrombogenicity of tissue engineered grafts

    PubMed Central

    Bruinsma, Bote G; Kim, Yeonhee; Berendsen, Tim A; Ozer, Sinan; Yarmush, Martin L; Uygun, Basak E

    2015-01-01

    Background Tissue-engineered liver grafts may offer a viable alternative to orthotopic liver transplantation and help overcome the donor organ shortage. Decellularized liver matrices (DLM) have a preserved vasculature and sustain hepatocellular function in culture, but graft survival after transplantation remains limited due to thrombogenicity of the matrix. Aim To evaluate the effect of heparin immobilization on DLM thrombogenicity. Methods Heparin was immobilized on DLMs by means of layer-by-layer deposition. Grafts with 4 or 8 bilayers and 2 or 4 g/L of heparin were recellularized with primary rat hepatocytes and maintained in culture for 5 days. Hemocompatibility of the graft was assessed by ex vivo diluted whole-blood perfusion and heterotopic transplantation. Results Heparin was deposited throughout the matrix and the heparin content in the graft was higher with increasing number of bilayers and concentration of heparin. Recellularization and in vitro albumin and urea production were unaffected by heparinization. Resistance to blood flow during ex vivo perfusion was lower with increased heparinization and, macroscopically, no clots were visible in grafts with 8 bilayers. Following transplantation, flow through the graft was limited in all groups. Histological evidence of thrombosis was lower in heparinized DLMs, but transplantation of DLM grafts was not improved. Conclusions Layer-by-layer deposition of heparin on a DLM is an effective method of immobilizing heparin throughout the graft and does not impede recellularization or hepatocellular function in vitro. Thrombogenicity during ex vivo blood perfusion was reduced in heparinized grafts and optimal with 8 bilayers, but transplantation remained unsuccessful with this method. Relevance for patients Tissue engineered liver grafts may offer a viable solution to dramatic shortages in donor organs PMID:26478914

  9. Albumin impregnated vascular grafts: albumin resorption and tissue reactions.

    PubMed

    Cziperle, D J; Joyce, K A; Tattersall, C W; Henderson, S C; Cabusao, E B; Garfield, J D; Kim, D U; Duhamel, R C; Greisler, H P

    1992-01-01

    This study aimed to determine the kinetics of albumin resorption from and the healing of two types of albumin impregnated Vasculour II (Bard Cardiovascular) Dacron grafts (ACG-A and ACG-B) using whole blood preclotted Vasculour II Dacron grafts (without albumin) as controls (PCC). Prostheses measuring 4 mm ID x 50 mm length were implanted in the aortoiliac position in 24 dogs (ACG-A n = 12, ACG-B n = 24, PCC n = 12) and explanted after 1, 2 4, and 6 months. Platelet count, platelet aggregometry to 10(-5) M ADP, prothrombin time (PT), and partial thromboplastin time (PTT) were determined preoperatively and at explantation. Sections of the explanted grafts were assayed for human albumin by immunohistochemical techniques utilizing a rabbit polyclonal mono-specific antibody for human albumin followed by the addition of a biotinylated goat anti-rabbit IgG. Immunoperoxidase staining was then performed using Avidin D horse-radish peroxidase. Histology of the grafts (light microscopy, scanning electron microscopy, and transmission electron microscopy) as well as percent thrombus free surface area (TFSA) by computerized planimetry were also determined. Seven of 48 grafts were occluded (85.4% patency) with no difference among the three groups. Platelet aggregometry was not predictive of graft patency. No change in PT or PTT occurred nor was there any difference among the three groups. Retained albumin was detected in every one-month explant but not beyond that time, with the sensitivity for detecting human albumin in this assay being 20 mg albumin per gram of Dacron. All ACG explants at one month revealed inner capsular fibrin coagula not present in PCC specimens.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1388174

  10. Revascularization of autogenous skin grafts placed on irradiated tissue

    SciTech Connect

    Ueda, M.; Torii, S.; Kaneda, T.; Oka, T.

    1982-08-01

    Vascular changes in rat skin after irradiation were examined microangiographically. Revascularization of the skin transplanted during the chronic stage after irradiation was also studied. The results obtained through these examinations revealed higher vascular densities at the acute and the subacute stages, and low values at the chronic stages compared with those of the control. Furthermore, when the skin grafts were transplanted to the irradiated beds in the chronic stage, primary revascularization was scant, and the inhibited capillary proliferation in the recipient sites prevented new vessel penetration. This explains why grafts transplanted to previously irradiated beds fail to survive.

  11. Tissue-engineered acellular small diameter long-bypass grafts with neointima-inducing activity.

    PubMed

    Mahara, Atsushi; Somekawa, Shota; Kobayashi, Naoki; Hirano, Yoshiaki; Kimura, Yoshiharu; Fujisato, Toshiya; Yamaoka, Tetsuji

    2015-07-01

    Researchers have attempted to develop efficient antithrombogenic surfaces, and yet small-caliber artificial vascular grafts are still unavailable. Here, we demonstrate the excellent patency of tissue-engineered small-caliber long-bypass grafts measuring 20-30 cm in length and having a 2-mm inner diameter. The inner surface of an acellular ostrich carotid artery was modified with a novel heterobifunctional peptide composed of a collagen-binding region and the integrin α4β1 ligand, REDV. Six grafts were transplanted in the femoral-femoral artery crossover bypass method. Animals were observed for 20 days and received no anticoagulant medication. No thrombogenesis was observed on the luminal surface and five cases were patent. In contrast, all unmodified grafts became occluded, and severe thrombosis was observed. The vascular grafts reported here are the first successful demonstrations of short-term patency at clinically applicable sizes. PMID:25941782

  12. Alveolar ridge augmentation by connective tissue grafting using a pouch method and modified connective tissue technique: A prospective study

    PubMed Central

    Agarwal, Ashish; Gupta, Narinder Dev

    2015-01-01

    Background: Localized alveolar ridge defect may create physiological and pathological problems. Developments in surgical techniques have made it simpler to change the configuration of a ridge to create a more aesthetic and more easily cleansable shape. The purpose of this study was to compare the efficacy of alveolar ridge augmentation using a subepithelial connective tissue graft in pouch and modified connective tissue graft technique. Materials and Methods: In this randomized, double blind, parallel and prospective study, 40 non-smoker individuals with 40 class III alveolar ridge defects in maxillary anterior were randomly divided in two groups. Group I received modified connective tissue graft, while group II were treated with subepithelial connective tissue graft in pouch technique. The defect size was measured in its horizontal and vertical dimension by utilizing a periodontal probe in a stone cast at base line, after 3 months, and 6 months post surgically. Analysis of variance and Bonferroni post-hoc test were used for statistical analysis. A two-tailed P < 0.05 was considered to be statistically significant. Results: Mean values in horizontal width after 6 months were 4.70 ± 0.87 mm, and 4.05 ± 0.89 mm for group I and II, respectively. Regarding vertical heights, obtained mean values were 4.75 ± 0.97 mm and 3.70 ± 0.92 mm for group I and group II, respectively. Conclusion: Within the limitations of this study, connective tissue graft proposed significantly more improvement as compare to connective tissue graft in pouch. PMID:26759591

  13. Infiltrating cells from host brain restore the microglial population in grafted cortical tissue.

    PubMed

    Wang, Cong; Tao, Sijue; Fang, Yukun; Guo, Jing; Zhu, Lirui; Zhang, Shengxiang

    2016-01-01

    Transplantation of embryonic cortical tissue is considered as a promising therapy for brain injury. Grafted neurons can reestablish neuronal network and improve cortical function of the host brain. Microglia is a key player in regulating neuronal survival and plasticity, but its activation and dynamics in grafted cortical tissue remain unknown. Using two-photon intravital imaging and parabiotic model, here we investigated the proliferation and source of microglia in the donor region by transplanting embryonic cortical tissue into adult cortex. Live imaging showed that the endogenous microglia of the grafted tissue were rapidly lost after transplantation. Instead, host-derived microglia infiltrated and colonized the graft. Parabiotic model suggested that the main source of infiltrating cells is the parenchyma of the host brain. Colonized microglia proliferated and experienced an extensive morphological transition and eventually differentiated into resting ramified morphology. Collectively, these results demonstrated that donor tissue has little contribution to the activated microglia and host brain controls the microglial population in the graft. PMID:27615195

  14. Antigen Removal for the Production of Biomechanically Functional, Xenogeneic Tissue Grafts

    PubMed Central

    Cissell, Derek D.; Hu, Jerry C.; Griffiths, Leigh G.; Athanasiou, Kyriacos A.

    2013-01-01

    Xenogeneic tissues are derived from other animal species and provide a source of material for engineering mechanically functional tissue grafts, such as heart valves, tendons, ligaments, and cartilage. Xenogeneic tissues, however, contain molecules, known as antigens, which invoke an immune reaction following implantation into a patient. Therefore, it is necessary to remove the antigens from a xenogeneic tissue to prevent immune rejection of the graft. Antigen removal can be accomplished by treating a tissue with solutions and/or physical processes that disrupt cells and solubilize, degrade, or mask antigens. However, processes used for cell and antigen removal from tissues often have deleterious effects on the extracellular matrix (ECM) of the tissue, rendering the tissue unsuitable for implantation due to poor mechanical properties. Thus, the goal of an antigen removal process should be to reduce the antigen content of a xenogeneic tissue while preserving its mechanical functionality. To expand the clinical use of antigen-removed xenogeneic tissues as biomechanically functional grafts, it is essential that researchers examine tissue antigen content, ECM composition and architecture, and mechanical properties as new antigen removal processes are developed. PMID:24268315

  15. Osteochondral Allograft of the Talus

    PubMed Central

    Bisicchia, Salvatore; Rosso, Federica; Amendola, Annunziato

    2014-01-01

    Osteochondral lesions of the talus are being recognized as an increasingly common injury. They are most commonly located postero-medially or antero-laterally, while centrally located lesions are uncommon. Large osteochondral lesions have significant biomechanical consequences and often require resurfacing with osteochondral autograft transfer, mosaicplasty, autologous chondrocyte implantation (or similar methods) or osteochondral allograft transplantation. Allograft procedures have become popular due to inherent advantages over other resurfacing techniques. Cartilage viability is one of the most important factors for successful clinical outcomes after transplantation of osteochondral allografts and is related to storage length and intra-operative factors. While there is abundant literature about osteochondral allograft transplantation in the knee, there are few papers about this procedure in the talus. Failure of non-operative management, initial debridement, curettage or microfractures are an indication for resurfacing. Patients should have a functional ankle motion, closed growth plates, absence of cartilage lesions on the tibial side. This paper reviews the published literature about osteochondral allograft transplantation of the talus focusing on indications, pre-operative planning, surgical approaches, postoperative management, results and complications of this procedure. PMID:25328456

  16. Osteochondral Autograft Transplantation: A Review of the Surgical Technique and Outcomes.

    PubMed

    Richter, Dustin L; Tanksley, John A; Miller, Mark D

    2016-06-01

    Isolated chondral and osteochondral defects of the knee are challenging clinical entities, particularly in younger patients. Cartilage treatment strategies have previously been characterized as palliation (ie, chondroplasty and debridement), repair (ie, drilling and microfracture), or restoration (ie, autologous chondrocyte implantation, osteochondral autograft, and osteochondral allograft). The osteochondral autograft transplantation procedure allows defects to be filled immediately with mature, hyaline articular cartilage by utilizing either an arthroscopic or a mini-open procedure. Graft harvest and placement can be technically demanding, but results show trends toward greater longevity, durability, and improved outcomes in high-demand patients when compared with alternative techniques. Improved results are shown in younger patients with isolated lesions between 1 and 4 cm. PMID:27135290

  17. Grinding and polishing instead of sectioning for the tissue samples with a graft: Implications for light and electron microscopy.

    PubMed

    Mukhamadiyarov, Rinat A; Sevostyanova, Victoria V; Shishkova, Daria K; Nokhrin, Andrey V; Sidorova, Olga D; Kutikhin, Anton G

    2016-06-01

    A broad use of the graft replacement requires a detailed investigation of the host-graft interaction, including both histological examination and electron microscopy. A high quality sectioning of the host tissue with a graft seems to be complicated; in addition, it is difficult to examine the same tissue area by both of the mentioned microscopy techniques. To solve these problems, we developed a new technique of epoxy resin embedding with the further grinding, polishing, and staining. Graft-containing tissues prepared by grinding and polishing preserved their structure; however, sectioning frequently required the explantation of the graft and led to tissue disintegration. Moreover, stained samples prepared by grinding and polishing may then be assessed by both light microscopy and backscattered scanning electron microscopy. Therefore, grinding and polishing outperform sectioning when applied to the tissues with a graft. PMID:27023831

  18. Bone Grafts

    MedlinePlus

    A bone graft transplants bone tissue. Surgeons use bone grafts to repair and rebuild diseased bones in your hips, knees, spine, and sometimes other bones and joints. Grafts can also repair bone loss caused by some ...

  19. Arthroscopically assisted autologous osteochondral transplantation for osteochondral lesions of the talar dome: an MRI and clinical follow-up study.

    PubMed

    Assenmacher, J A; Kelikian, A S; Gottlob, C; Kodros, S

    2001-07-01

    Osteochondral Lesions of the Talar Dome (OLT) are common problems encountered in orthopedics. Although the etiology remains uncertain, a myriad of treatment options exists. The authors describe arthroscopically assisted autologous osteochondral graft (OCG) transplantation procedures in the treatment of unstable OLTs in nine patients. The patients underwent standard preoperative MRI examination to assess fragment stability (using De Smet criteria for stability). Intraoperative arthroscopy was used to correlate the preoperative MRI assessment (using Cheng/Ferkel grading). After transplantation procedures, MRI (using De Smet criteria for stability) assessed graft incorporation for stability at an average of 9.3 months after the procedure. Preoperative MRI correlated highly with arthroscopic findings of OLT instability (sensitivity = 1.0). This has been demonstrated in the current orthopedic literature. The post transplantation MRI demonstrated stable graft osteointegration by De Smet criteria in all patients. Postoperative visual analogue pain scales showed significant improvement from preoperative assessment. Postoperative AOFAS Ankle-Hindfoot scores averaged 80.2 (S.D. +/- 18.9). Our favorable early results and those of other authors using similar techniques may validate OCG transplantation as a viable alternative for treating unstable osteochondral defects in the talus that are refractive to more commonly used surgical techniques. PMID:11503978

  20. Survival of cultured plant cells grafted into the subcutaneous tissue of rats (preliminary report).

    PubMed

    Lozoya, X; Madrazo, I; Guizar, G; Villarreal, M L; Grijalva, I; Salgado, H; Boijseauneau, E; Ibarra, A; Arias-Castro, C; Rodríguez-Mendiola, M A

    1995-01-01

    To evaluate the survival of plant tissue in an animal environment, cultured calli from a Mexican medicinal plant (Mimosa tenuiflora Poir.) were transplanted under sterile conditions into the subcutaneous tissue of rats. Microscopic studies of grafted areas were carried out at the 30th, 60th and 120th days after transplantation. Histological evidence of plant graft survival was found in specimens of all groups. during the first month of subcutaneous grafting a moderate inflammatory reaction around the callus was observed characterized by the presence of polymorphonuclear cells and some macrophages and the formation of a fibrous capsule. Nevertheless, the plant grafts remained viable and a decrease of the inflammatory reaction around the callus was observed in the specimens during the following months. In the fourth month specimens the formation of blood vessels inside the grafted plant tissue was observed. Once removed from rats, plant tissues showed high viability according to the fluorescein test. These calli were then transferred to the original in vitro medium showing growth capacity during the following weeks. These results demonstrate, for the first time, that cultivated cells of higher plants survive in an animal environment, suggesting the possibility to utilize pharmacologically active plant transplants in animals, a technique proposed here as inter-regni transplants. Further studies are required to explore this new field of research that opens numerous questions about plant-animal cellular interaction. PMID:7711454

  1. A Novel Local Autologous Bone Graft Donor Site After Scalp Tissue Expansion in Aplasia Cutis Congenita.

    PubMed

    Hadad, Ivan; Meara, John G; Rogers-Vizena, Carolyn R

    2016-06-01

    Aplasia cutis congenita (ACC) is a rare condition often presenting as an absent area of cutaneous scalp. The calvarium and dura may also be affected. Scalp reconstruction with tissue expansion is often needed for large defects. Patients involving deficient calvarial bone present a dilemma for the reconstructive surgeon, because bone graft donor sites are limited in young children.A thick, bony rim has been noted to form around the periphery of scalp tissue expanders. The authors present a series of 3 patients with ACC for whom this bony hyperostosis was used as donor particulate bone graft at the time of scalp tissue expansion. There was 85 to 100% graft ossification on postoperative computed tomography scan. There were no bone graft-related complications.In conclusion, the hyperostotic rim that forms after scalp tissue expansion can be successfully used as particulate bone graft, decreasing the number of procedures needed for patient with ACC and obviating the need for other donor sites. PMID:27192637

  2. Adipose tissue-derived stem cell therapy in rat cryopreserved ovarian grafts.

    PubMed

    Damous, Luciana Lamarão; Nakamuta, Juliana Sanajotti; de Carvalho, Ana Elisa Teófilo Saturi; Soares-Jr, José Maria; de Jesus Simões, Manuel; Krieger, José Eduardo; Baracat, Edmund C

    2015-01-01

    The preliminary results of ovarian transplantation in clinical practice are encouraging. However, the follicular depletion caused by ischemic injury is a main concern and is directly related to short-term graft survival. Cell therapy with adipose tissue-derived stem cells (ASCs) could be an alternative to induce early angiogenesis in the graft. This study aimed to evaluate ASCs therapy in rat cryopreserved ovarian grafts. A single dose of rat ASC (rASCs) or vehicle was injected into the bilateral cryopreserved ovaries of twelve adult female rats immediately after an autologous transplant. Daily vaginal smears were performed for estrous cycle evaluation until euthanasia on postoperative day 30. Follicle viability, graft morphology and apoptosis were assessed. No differences were found with respect to estrous cycle resumption and follicle viability (P>0.05). However, compared with the vehicle-treated grafts, the morphology of the ASCs-treated grafts was impaired, with diffuse atrophy and increased apoptosis (P<0.05). ASCs direct injected in the stroma of rat cryopreserved ovarian grafts impaired its morphology although may not interfere with the functional resumption on short-term. Further investigations are necessary to evaluated whether it could compromise their viability in the long-term. PMID:25889829

  3. Progress in Corneal Stromal Repair: From Tissue Grafts and Biomaterials to Modular Supramolecular Tissue-Like Assemblies.

    PubMed

    Kumar, Pramod; Pandit, Abhay; Zeugolis, Dimitrios I

    2016-07-01

    Corneal injuries and degenerative conditions have major socioeconomic consequences, given that in most cases, they result in blindness. In the quest of the ideal therapy, tissue grafts, biomaterials, and modular engineering approaches are under intense investigation. Herein, advancements and shortfalls are reviewed and future perspectives for these therapeutic strategies discussed. PMID:27028373

  4. Arthroscopically Assisted Anatomic Coracoclavicular Ligament Reconstruction Technique Using Coracoclavicular Fixation and Soft-Tissue Grafts

    PubMed Central

    Millett, Peter J.; Warth, Ryan J.; Greenspoon, Joshua A.; Horan, Marilee P.

    2015-01-01

    Acromioclavicular joint injuries are common and are often seen in contact athletes. Good to excellent clinical results have been reported using soft-tissue grafts to reconstruct the coracoclavicular ligaments; however, complications remain. Some complications are unique to the surgical technique, particularly clavicle and coracoid fractures that are associated with drilling large or multiple bone tunnels. The described technique allows for an anatomic coracoclavicular reconstruction using a large soft-tissue graft while minimizing the risk of clavicle fracture by avoiding large bone tunnels. PMID:26900558

  5. Grafting of nigral tissue hibernated with tirilazad mesylate and glial cell line-derived neurotrophic factor.

    PubMed

    Petersen, A; Hansson, O; Emgård, M; Brundin, P

    2000-01-01

    Transplantation of embryonic ventral mesencephalon is a potential therapy for patients with Parkinson's disease. As only around 5-10% of embryonic dopaminergic neurons survive grafting into the adult striatum, it is considered necessary to use multiple donor embryos. To increase the survival of the grafted dopaminergic neurons, the clinical transplantation program in Lund currently employs the lipid peroxidation inhibitor, tirilazad mesylate, in all solutions used during tissue storage, preparation, and transplantation. However, the difficulty in obtaining a sufficient number of donor embryos still remains an important limiting factor for the clinical application of neural transplantation. In many clinical transplantation programs, it would be a great advantage if human nigral donor tissue could be stored for at least 1 week. This study was performed in order to investigate whether storage of embryonic tissue at 4 degrees C for 8 days can be applied clinically without creating a need to increase the number of donors. We compared the survival of freshly grafted rat nigral tissue, prepared according to the clinical protocol, with tissue transplanted after hibernation. Thus, in all groups tirilazad mesylate was omnipresent. One group of rats was implanted with fresh tissue and three groups with hibernated tissue with or without addition of glial cell line-derived neurotrophic factor (GDNF) in the hibernation medium and/or the final cell suspension. Earlier studies have suggested that GDNF improves the survival of hibernated nigral transplants. We found no statistically significant difference between the groups regarding graft survival after 3 weeks. However, there was a nonsignificant trend for fewer surviving dopaminergic neurons in grafts from hibernated tissue compared to fresh controls. Furthermore, we show that the addition of GDNF to the hibernation medium and/or to the final cell suspension does not significantly increase the survival of the dopaminergic

  6. Orbital dermis-fat graft using periumbilical tissue.

    PubMed

    Bonavolontà, G; Tranfa, F; Salicone, A; Strianese, D

    2000-01-01

    Dermis-fat grafts are currently used in orbital reconstruction in a variety of procedures. The most frequent harvesting site is the gluteal area. However, we encountered some patients with anophthalmic socket who wished to avoid a visible scar on the buttock. In this article, we describe the effort to offer the patient an alternative donor site. Of the last 36 patients with anophthalmic socket who needed a dermal fat implant, 11 wished to avoid a visible scar on the buttock. To satisfy their requests we have endeavored to harvest the dermis graft from the periumbilical area. The rate of absorption, the motility, and the satisfaction of the patients were used as outcome measures and were analyzed carefully. Of 11 patients, 4 were women and 7 were men. The ages of these patients ranged from 24 to 56. The maximum follow-up was 137 months and the minimum 22 months, with a mean follow-up of 79 months. Some degree of absorption of the graft developed in one patient who had a severe absorption and required further operation. Of 11 cases, there were 7 with excellent motility, 3 with good motility, and 1 not evaluated. The motility was measured with the final prosthesis. The results for all patients were satisfactory. The periumbilical area has sufficient concentration of subdermal fat, and it is a relatively hair-free region as the lateral quadrant of the buttock. This area is a suitable alternative donor site of dermal fat implant for anophthalmic socket, especially in young women. PMID:10626965

  7. How I Manage Osteochondritis Dissecans.

    ERIC Educational Resources Information Center

    DiStefano, Vincent J.

    1986-01-01

    Osteochondritis dissecans, a lesion found most often on the femur at the knee joint, occurs most frequently in active adolescents. This article describes treatment for preadolescents, adolescents, and adults. Osteochondritus dissecans of the patella is also presented. (MT)

  8. The Treatment of Osteochondral Lesions of the Talus with Autologous Osteochondral Transplantation and Bone Marrow Aspirate Concentrate

    PubMed Central

    Kennedy, John G.; Murawski, Christopher D.

    2011-01-01

    Objective: To present the functional results after autologous osteochondral transplantation with bone marrow aspirate concentrate in 72 patients, while placing an emphasis on the surgical technique. Methods: Between 2005 and 2009, 72 patients underwent autologous osteochondral transplantation under the care of the senior author. The mean patient age at the time of surgery was 34.19 years (range, 16-85 years). All patients were followed for a minimum of 1 year after surgery. The mean follow-up time was 28.02 months (range, 12-64 months). Patient-reported outcome measures were taken preoperatively and at final follow-up using the Foot and Ankle Outcome Score (FAOS) and Short Form–12 (SF-12) general health questionnaire. Identical questionnaires were used in all instances. Results: The mean FAOS scores improved from 52.67 points preoperatively to 86.19 points postoperatively (range, 71-100 points). The mean SF-12 scores also improved from 59.40 points preoperatively to 88.63 points postoperatively (range, 52-98 points). Three patients reported donor site knee pain after surgery, and one patient required the decompression of a cyst that developed beneath the graft site approximately 2 years after the index procedure. Conclusion: Autologous osteochondral transplantation is a reproducible and primary treatment strategy for large osteochondral lesions of the talus. PMID:26069591

  9. Osteochondral Autograft from the Ipsilateral Femoral Head by Surgical Dislocation for Treatment of Femoral Head Fracture Dislocation: A Case Report.

    PubMed

    Won, Yougun; Lee, Gi Soo; Kim, Sang Bum; Kim, Sun Joong; Yang, Kyu Hyun

    2016-11-01

    As anatomical reduction of the articular surface of femoral head fractures and restoration of damaged cartilage are essential for good long-term results, many treatment options have been suggested, including fixation of the fracture using various surgical exposures and implants, as well as arthroscopic irrigation and debridement, bone marrow stimulating techniques, osteochondral allograft, autograft, and autogenous chondrocyte implantation. We report a case of osteochondral autograft harvested from its own femoral articular surface through surgical hip dislocation. The osteochondral graft was harvested from the inferior non-weight-bearing articular surface and grafted to the osteochondral defect. One year later, the clinical and radiological results were good, without the collapse of the femoral head or arthritic change. This procedure introduced in our case is considered convenient and able to lessen surgical time without morbidity of the donor site associated with the harvest. PMID:27593886

  10. Ectopic porcine spermatogenesis in murine subcutis: tissue grafting versus cell-injection methods

    PubMed Central

    Watanabe, Takeshi; Hayashi, Hirofumi; Kita, Kaoru; Kubota, Yoshinobu; Ogawa, Takehiko

    2009-01-01

    Fragments of testis tissue from immature animals grow and develop spermatogenesis when grafted onto subcutaneous areas of immunodeficient mice. The same results are obtained when dissociated cells from immature testes of rodents are injected into the subcutis of nude mice. Those cells reconstitute seminiferous tubules and facilitate spermatogenesis. We compared these two methods, tissue grafting and cell-injection methods, in terms of the efficiency of spermatogenesis in the backs of three strains of immunodeficient mice, using neonatal porcine testicular tissues and cells as donor material. Nude, severe combined immunodeficient (SCID) and NOD/Shi-SCID, IL-2Rγcnull (NOG) mice were used as recipients. At 10 months after surgery, the transplants were examined histologically. Both grafting and cell-injection methods resulted in porcine spermatogenesis on the backs of recipient mice; the percentage of spermatids present in the transplants was 67% and 22%, respectively. Using the grafting method, all three strains of mice supported the same extent of spermatogenesis. As for the cell-injection method, although SCID mice were the best host for supporting reconstitution and spermatogenesis, any difference from the other strains was not significant. As NOG mice did not show any better results, the severity of immunodeficiency seemed to be irrelevant for supporting xeno-ectopic spermatogenesis. Our results confirmed that tubular reconstitution is applicable to porcine testicular cells. This method as well as the grafting method would be useful for studying spermatogenesis in different kinds of animals. PMID:19137001

  11. Tissue specificity in rat peripheral nerve regeneration through combined skeletal muscle and vein conduit grafts.

    PubMed

    Tos, P; Battiston, B; Geuna, S; Giacobini-Robecchi, M G; Hill, M A; Lanzetta, M; Owen, E R

    2000-01-01

    Diffusible factors from the distal stumps of transected peripheral nerves exert a neurotropic effect on regenerating nerves in vivo (specificity). This morphological study was designed to investigate the existence of tissue specificity in peripheral nerve fiber regeneration through a graft of vein filled with fresh skeletal muscle. This tubulization technique demonstrated experimental and clinical results similar to those obtained with traditional autologous nerve grafts. Specifically, we used Y-shaped grafts to assess the orientation pattern of regenerating axons in the distal stump tissue. Animal models were divided into four experimental groups. The proximal part of the Y-shaped conduit was sutured to a severed tibial nerve in all experiments. The two distal stumps were sutured to different targets: group A to two intact nerves (tibial and peroneal), group B to an intact nerve and an unvascularized tendon, group C to an intact nerve and a vascularized tendon, and group D to a nerve graft and an unvascularized tendon. Morphological evaluation by light and electron microscopy was conducted in the distal forks of the Y-shaped tube. Data showed that almost all regenerating nerve fibers spontaneously oriented towards the nerve tissue (attached or not to the peripheral innervation field), showing a good morphological pattern of regeneration in both the early and late phases of regeneration. When the distal choice was represented by a tendon (vascularized or not), very few nerve fibers were detected in the corresponding distal fork of the Y-shaped graft. These results show that, using the muscle-vein-combined grafting technique, regenerating axons are able to correctly grow and orientate within the basement membranes of the graft guided by the neurotropic lure of the distal nerve stump. PMID:10702739

  12. Vascularisation of tissue-engineered grafts: the regulation of angiogenesis in reconstructive surgery and in disease states.

    PubMed

    Cassell, O C S; Hofer, S O P; Morrison, W A; Knight, K R

    2002-12-01

    Angiogenesis (the formation of new blood vessels) is essential for the growth of new tissue, tissue repair and wound healing. Tissue engineering, the construction of new tissue and organs for reparative purposes, relies on angiogenesis for the vascularisation of these new grafts. In tissue engineering, the emphasis to date has been on vascularisation of newly constructed tissue grafts by an extrinsic blood supply, and relatively little attention has been given to the possibility of building these grafts around an intrinsic blood supply. However, there are many disease processes, notably tumour growth, where excess angiogenesis can be a major problem. The purposes of this review are, first, to examine various methods of vascularising tissue-engineered grafts, and, second, to compare the role of angiogenesis in tissue engineering, where stimulation of angiogenesis is paramount, with pathological states, such as tumour growth, where angiogenesis needs to be inhibited. PMID:12550111

  13. Effect of different cryoprotectant agents on spermatogenesis efficiency in cryopreserved and grafted neonatal mouse testicular tissue.

    PubMed

    Yildiz, Cengiz; Mullen, Brendan; Jarvi, Keith; McKerlie, Colin; Lo, Kirk C

    2013-08-01

    Restoration of male fertility associated with use of the cryopreserved testicular tissue would be a significant advance in human and animal assisted reproductive technology. The purpose of this study was to test the effects of four different cryoprotectant agents (CPA) on spermatogenesis and steroidogenesis in cryopreserved and allotransplanted neonatal mouse testicular tissue. Hank's balanced salt solution (HBSS) with 5% fetal bovine serum including either 0.7 M dimethyl sulfoxide (DMSO), 0.7 M propylene glycol (PrOH), 0.7 M ethylene glycol (EG), or glycerol was used as the cryoprotectant solution. Donor testes were collected and dissected from neonatal pups of CD-1 mice (one day old). Freezing and seeding of the testicular whole tissues was performed using an automated controlled-rate freezer. Four fresh (non-frozen) or frozen-thawed pieces of testes were subcutaneously grafted onto the hind flank of each castrated male NCr nude recipient mouse and harvested after 3 months. Fresh neonatal testes grafts recovered from transplant sites had the most advanced rate of spermatogenesis with elongated spermatid and spermatozoa in 46.6% of seminiferous tubules and had higher levels of serum testosterone compared to all other frozen-thawed-graft groups (p<0.05). Fresh grafts and frozen-thawed grafts in the DMSO group had the highest rate of tissue survival compared to PrOH, EG, and glycerol after harvesting (p>0.05). The most effective CPA for the freezing and thawing of neonatal mouse testes was DMSO in comparison with EG (p<0.05) in both pre-grafted and post-grafted tissues based on histopathological evaluation. Likewise, the highest level of serum testosterone was obtained from the DMSO CPA group compared to all other cryoprotectants evaluated (p<0.05). The typical damage observed in the frozen-thawed grafts included disruption of the interstitial stroma, intercellular connection ruptures, and detachment of spermatogonia from the basement membrane. These findings

  14. Treatment of osteochondral injuries with platelet gel

    PubMed Central

    Danieli, Marcus Vinicius; da Rosa Pereira, Hamilton; de Sá Carneiro, Carlos Augusto; Felisbino, Sérgio Luiz; Deffune, Elenice

    2014-01-01

    OBJECTIVES: Treatments for injured articular cartilage have not advanced to the point that efficient regeneration is possible. However, there has been an increase in the use of platelet-rich plasma for the treatment of several orthopedic disorders, including chondral injuries. Our hypothesis is that the treatment of chondral injuries with platelet gel results in higher-quality repair tissue after 180 days compared with chondral injuries not treated with gel. METHODS: A controlled experimental laboratory study was performed on 30 male rabbits to evaluate osteochondral injury repair after treatment with or without platelet gel. Osteochondral injuries were surgically induced in both knees of each rabbit at the medial femoral condyle. The left knee injury was filled with the platelet gel, and the right knee was not treated. Microscopic analysis of both knee samples was performed after 180 days using a histological grading scale. RESULTS: The only histological evaluation criterion that was not significantly different between treatments was metachromasia. The group that was treated with platelet gel exhibited superior results in all other criteria (cell morphology, surface regularity, chondral thickness and repair tissue integration) and in the total score. CONCLUSION: The repair tissue was histologically superior after 180 days in the study group treated with platelet gel compared with the group of untreated injuries. PMID:25518022

  15. Tissue Characterization after a New Disaggregation Method for Skin Micro-Grafts Generation.

    PubMed

    Purpura, Valeria; Bondioli, Elena; Graziano, Antonio; Trovato, Letizia; Melandri, Davide; Ghetti, Martina; Marchesini, Andrea; Cusella De Angelis, Maria Gabriella; Benedetti, Laura; Ceccarelli, Gabriele; Riccio, Michele

    2016-01-01

    Several new methods have been developed in the field of biotechnology to obtain autologous cellular suspensions during surgery, in order to provide one step treatments for acute and chronic skin lesions. Moreover, the management of chronic but also acute wounds resulting from trauma, diabetes, infections and other causes, remains challenging. In this study we describe a new method to create autologous micro-grafts from cutaneous tissue of a single patient and their clinical application. Moreover, in vitro biological characterization of cutaneous tissue derived from skin, de-epidermized dermis (Ded) and dermis of multi-organ and/or multi-tissue donors was also performed. All tissues were disaggregated by this new protocol, allowing us to obtain viable micro-grafts. In particular, we reported that this innovative protocol is able to create bio-complexes composed by autologous micro-grafts and collagen sponges ready to be applied on skin lesions. The clinical application of autologous bio-complexes on a leg lesion was also reported, showing an improvement of both re-epitalization process and softness of the lesion. Additionally, our in vitro model showed that cell viability after mechanical disaggregation with this system is maintained over time for up to seven (7) days of culture. We also observed, by flow cytometry analysis, that the pool of cells obtained from disaggregation is composed of several cell types, including mesenchymal stem cells, that exert a key role in the processes of tissue regeneration and repair, for their high regenerative potential. Finally, we demonstrated in vitro that this procedure maintains the sterility of micro-grafts when cultured in Agar dishes. In summary, we conclude that this new regenerative approach can be a promising tool for clinicians to obtain in one step viable, sterile and ready to use micro-grafts that can be applied alone or in combination with most common biological scaffolds. PMID:26967938

  16. Development of a Sterile Amniotic Membrane Tissue Graft Using Supercritical Carbon Dioxide.

    PubMed

    Wehmeyer, Jennifer L; Natesan, Shanmugasundaram; Christy, Robert J

    2015-07-01

    Numerous techniques have been reported for preparing and sterilizing amniotic membrane (AM) for use in clinical applications. However, these preparations either do not produce completely sterile tissue or are detrimental to molecules unique to the tissue matrix, thus compromising beneficial wound-healing properties of the AM graft. The objective of this work was to produce a sterile human AM tissue graft using a novel preparation technique involving supercritical carbon dioxide (SCCO2). AM tissue was subjected to various sterilization treatment groups that optimized the duration of exposure to SCCO2 and the amount of peracetic acid (PAA) required to achieve a sterility assurance level of 10(-6) log reduction in bacterial load. Effects of sterilization treatment on the histological, biophysical, and biochemical properties of the sterile AM were evaluated and compared with those of native AM tissue. Exposure of the AM tissue to combined SCCO2 and PAA sterilization treatment did not significantly alter tissue architecture, the amounts of pertinent extracellular matrix proteins (type IV collagen, glycosaminoglycans, elastin) present in the tissue, or the biophysical properties of the tissue. AMs treated with SCCO2 were also found to be excellent substrates for adipose-derived stem cell (ASC) attachment and proliferation in vitro. Human ASCs, attached to all treatment groups after 24 h of culture and continued to proliferate over the next few days. The current study's results indicate that SCCO2 can be used to sterilize AM tissue grafts while simultaneously preserving their biological attributes. The preservation of these features make AM appealing for use in numerous clinical and tissue engineering applications. PMID:25471248

  17. Design and optimization of a tissue-engineered bone graft substitute

    NASA Astrophysics Data System (ADS)

    Shimko, Daniel Andrew

    2004-12-01

    In 2000, 3.1 million surgical procedures on the musculoskeletal system were reported in the United States. For many of these cases, bone grafting was essential for successful fracture stabilization. Current techniques use intact bone obtained either from the patient (autograft) or a cadaver (allograft) to repair large defects, however, neither source is optimal. Allografts suffer integration problems, and for autografts, the tissue supply is limited. Because of these shortcomings, and the high demand for graft tissues, alternatives are being explored. To successfully engineer a bone graft replacement, one must employ a three pronged research approach, addressing (1) the cells that will inhabit the new tissue, (2) the culture environment that these cells will be exposed to, and (3) the scaffold in which these cells will reside. The work herein examines each of these three aspects in great detail. Both adult and embryonic stem cells (ESCs) were considered for the tissue-engineered bone graft. Both exhibited desirable qualities, however, neither were optimal in all categories examined. In the end, the possibility of teratoma formation and ethical issues surrounding ESCs, made the use of adult marrow-derived stem cells in the remaining experiments obligatory. In subsequent experiments, the adult stem cells' ability to form bone was optimized. Basic fibroblast growth factor, fetal bovine serum, and extracellular calcium supplementation studies were all performed. Ultimately, adult stem cells cultured in alpha-MEM supplemented with 10% fetal bovine serum, 10mM beta-glycerophosphate, 10nM dexamethasone, 50mug/ml ascorbic acid, 1%(v/v) antibiotic/antimycotic, and 10.4mM CaCl2 performed the best, producing nearly four times more mineral than any other medium formulation. Several scaffolds were then investigated including those fabricated from poly(alpha-hydroxy esters), tantalum, and poly-methylmethacrylate. In the final study, the most appealing cell type, medium

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

    PubMed Central

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

    2016-01-01

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

  19. Three-dimensional osteochondral microtissue to model pathogenesis of osteoarthritis.

    PubMed

    Lozito, Thomas P; Alexander, Peter G; Lin, Hang; Gottardi, Riccardo; Cheng, Anthony Wai-Ming; Tuan, Rocky S

    2013-01-01

    Osteoarthritis (OA), the most prevalent form of arthritis, affects up to 15% of the adult population and is principally characterized by degeneration of the articular cartilage component of the joint, often with accompanying subchondral bone lesions. Understanding the mechanisms underlying the pathogenesis of OA is important for the rational development of disease-modifying OA drugs. While most studies on OA have focused on the investigation of either the cartilage or the bone component of the articular joint, the osteochondral complex represents a more physiologically relevant target because the disease ultimately is a disorder of osteochondral integrity and function. In our current investigation, we are constructing an in vitro three-dimensional microsystem that models the structure and biology of the osteochondral complex of the articular joint. Osteogenic and chondrogenic tissue components are produced using adult human mesenchymal stem cells derived from bone marrow and adipose seeded within biomaterial scaffolds photostereolithographically fabricated with defined internal architecture. A three-dimensional-printed, perfusion-ready container platform with dimensions to fit into a 96-well culture plate format is designed to house and maintain the osteochondral microsystem that has the following features: an anatomic cartilage/bone biphasic structure with a functional interface; all tissue components derived from a single adult mesenchymal stem cell source to eliminate possible age/tissue-type incompatibility; individual compartments to constitute separate microenvironment for the synovial and osseous components; accessible individual compartments that may be controlled and regulated via the introduction of bioactive agents or candidate effector cells, and tissue/medium sampling and compositional assays; and compatibility with the application of mechanical load and perturbation. The consequences of mechanical injury, exposure to inflammatory cytokines, and

  20. Direct Comparison of Rat- and Human-Derived Ganglionic Eminence Tissue Grafts on Motor Function.

    PubMed

    Lelos, Mariah J; Roberton, Victoria H; Vinh, Ngoc-Nga; Harrison, Carl; Eriksen, Peter; Torres, Eduardo M; Clinch, Susanne P; Rosser, Anne E; Dunnett, Stephen B

    2016-01-01

    Huntington's disease (HD) is a debilitating, genetically inherited neurodegenerative disorder that results in early loss of medium spiny neurons from the striatum and subsequent degeneration of cortical and other subcortical brain regions. Behavioral changes manifest as a range of motor, cognitive, and neuropsychiatric impairments. It has been established that replacement of the degenerated medium spiny neurons with rat-derived fetal whole ganglionic eminence (rWGE) tissue can alleviate motor and cognitive deficits in preclinical rodent models of HD. However, clinical application of this cell replacement therapy requires the use of human-derived (hWGE), not rWGE, tissue. Despite this, little is currently known about the functional efficacy of hWGE. The aim of this study was to directly compare the ability of the gold standard rWGE grafts, against the clinically relevant hWGE grafts, on a range of behavioral tests of motor function. Lister hooded rats either remained as unoperated controls or received unilateral excitotoxic lesions of the lateral neostriatum. Subsets of lesioned rats then received transplants of either rWGE or hWGE primary fetal tissue into the lateral striatum. All rats were tested postlesion and postgraft on the following tests of motor function: staircase test, apomorphine-induced rotation, cylinder test, adjusting steps test, and vibrissae-evoked touch test. At 21 weeks postgraft, brain tissue was taken for histological analysis. The results revealed comparable improvements in apomorphine-induced rotational bias and the vibrissae test, despite larger graft volumes in the hWGE cohort. hWGE grafts, but not rWGE grafts, stabilized behavioral performance on the adjusting steps test. These results have implications for clinical application of cell replacement therapies, as well as providing a foundation for the development of stem cell-derived cell therapy products. PMID:26727032

  1. Tissue-engineered vascular grafts: autologous off-the-shelf vascular access?

    PubMed

    Manson, Roberto J; Unger, Joshua M; Ali, Aamna; Gage, Shawn M; Lawson, Jeffrey H

    2012-11-01

    Dialysis grafts have provided reliable access for millions of patients in need of renal replacement therapy. However, regardless of the material used for artificial dialysis grafts their mean patency remains generally poor and infection rates are greater than native arteriovenous fistulas. The need for superior alternatives to conventional synthetic materials used for vascular access has been an area of investigation for more than 25 years and recently there has been a great deal of progress in the field of tissue-engineered vascular grafts. Many of these technologies are either commercially available or are now entering early phases of clinical trials. This review briefly covers the history, potential advantages, and disadvantages of these technologies, which are likely to create an impact in the field of vascular access surgery. PMID:23217339

  2. Current trends in safety assurance for tissue grafts used in burn treatment.

    PubMed

    Mericka, P

    2006-01-01

    The author presents a summary of current safety standards for allogeneic and xenogeneic biological skin grafts. The fundamental document relevant to allogeneic transplants, establishing the minimal level of safety guaranteed in European Union states, is the European Parliament and Council Directive (2004/23/EC) from March 31st 2004. This Directive determines that grafts will be prepared by a licensed or accredited tissue bank, and that this arrangement must be put in place by the member states within 2 years. In the Czech Republic licensing of tissue banks took place immediately after issuance of the Directive. Licensing was also a condition for product reimbursement by insurance companies. To gain a licence, tissue banks had to fulfil many safety criteria associated with screening of living or deceased donors for health suitability, providing traceability of the donor-recipient route, prevention of secondary and cross-contamination during processing and storage of the harvested tissues, proof of product microbiology check up, and cold chain control. The Tissue Bank of the Faculty Hospital in Hradec Králové is one of the two tissue banks that gained the broader type of 'multifunctional' licence and was granted registration number MTB 006. Obtaining the licence was facilitated by completion of a new workplace project conceived as a combination of cryogenic and clean-room technology. Currently, this tissue bank prepares cryopreserved dermoepidermal and dermal grafts as well as amnion and chorioamnion grafts. All tissue banks will have to renew their licences again according to the conditions established by a new law about human tissues and cells which is currently in preparation. Neither the Directive of the European Parliament nor the Transplantation Law of the Czech Republic regulates the issue of xenografts. Since availability of allogeneic biological covers is limited, it is significant that the WHO perspective on the use of xenogeneic biological covers, as

  3. Diagnosing, planning and evaluating osteochondral ankle defects with imaging modalities.

    PubMed

    van Bergen, Christiaan Ja; Gerards, Rogier M; Opdam, Kim Tm; Terra, Maaike P; Kerkhoffs, Gino Mmj

    2015-12-18

    This current concepts review outlines the role of different imaging modalities in the diagnosis, preoperative planning, and follow-up of osteochondral ankle defects. An osteochondral ankle defect involves the articular cartilage and subchondral bone (usually of the talus) and is mostly caused by an ankle supination trauma. Conventional radiographs are useful as an initial imaging tool in the diagnostic process, but have only moderate sensitivity for the detection of osteochondral defects. Computed tomography (CT) and magnetic resonance imaging (MRI) are more accurate imaging modalities. Recently, ultrasonography and single photon emission CT have been described for the evaluation of osteochondral talar defects. CT is the most valuable modality for assessing the exact location and size of bony lesions. Cartilage and subchondral bone damage can be visualized using MRI, but the defect size tends to be overestimated due to bone edema. CT with the ankle in full plantar flexion has been shown a reliable tool for preoperative planning of the surgical approach. Postoperative imaging is useful for objective assessment of repair tissue or degenerative changes of the ankle joint. Plain radiography, CT and MRI have been used in outcome studies, and different scoring systems are available. PMID:26716090

  4. On the influence of mechanical conditions in osteochondral defect healing.

    PubMed

    Duda, Georg N; Maldonado, Zully M; Klein, Petra; Heller, Markus O W; Burns, Justin; Bail, Hermann

    2005-04-01

    Despite the introduction of new surgical techniques, the treatment of cartilage defects remains challenging. Delay or complete failure of cartilage healing is associated with problems in biological regeneration. The influence of mechanical conditions on this process, however, remains unevaluated. Osteochondral defects were generated on the left femoral condyle in 18 Yucatan minipigs. After 4, 6 and 12 weeks the defect filling, trabecular orientation and bone density were compared to the intact contralateral side. The mechanical straining during this period was then analyzed using an adaptive finite element technique. Histologically, the osteochondral defects showed bone resorption at the base and bone formation from the circumference. At 12 weeks, the macroscopically healed specimens showed fibrous cartilage formation, a minimally organized trabecular structure and increased trabecular volume fraction compared to the controls (p < 0.002). The amount of cancellous, cartilagineous, and fibrous tissue and the defect size as measured in histomorphometric analysis for the three time points (4, 6 and 12 weeks) was comparable in magnitude to that predicted by finite element analysis. The simulated osteochondral healing process was not fully capable of re-establishing a hyaline-like cartilage layer. The correlation between simulation and histology allows identification of mechanical factors that appear to have a larger impact on the healing of osteochondral defects than previously considered. PMID:15713306

  5. Diagnosing, planning and evaluating osteochondral ankle defects with imaging modalities

    PubMed Central

    van Bergen, Christiaan JA; Gerards, Rogier M; Opdam, Kim TM; Terra, Maaike P; Kerkhoffs, Gino MMJ

    2015-01-01

    This current concepts review outlines the role of different imaging modalities in the diagnosis, preoperative planning, and follow-up of osteochondral ankle defects. An osteochondral ankle defect involves the articular cartilage and subchondral bone (usually of the talus) and is mostly caused by an ankle supination trauma. Conventional radiographs are useful as an initial imaging tool in the diagnostic process, but have only moderate sensitivity for the detection of osteochondral defects. Computed tomography (CT) and magnetic resonance imaging (MRI) are more accurate imaging modalities. Recently, ultrasonography and single photon emission CT have been described for the evaluation of osteochondral talar defects. CT is the most valuable modality for assessing the exact location and size of bony lesions. Cartilage and subchondral bone damage can be visualized using MRI, but the defect size tends to be overestimated due to bone edema. CT with the ankle in full plantar flexion has been shown a reliable tool for preoperative planning of the surgical approach. Postoperative imaging is useful for objective assessment of repair tissue or degenerative changes of the ankle joint. Plain radiography, CT and MRI have been used in outcome studies, and different scoring systems are available. PMID:26716090

  6. Skeletal Muscle Regeneration on Protein-Grafted and Microchannel-Patterned Scaffold for Hypopharyngeal Tissue Engineering

    PubMed Central

    Shen, Zhisen; Guo, Shanshan; Ye, Dong; Chen, Jingjing; Kang, Cheng; Qiu, Shejie; Lu, Dakai; Li, Qun; Xu, Kunjie; Lv, Jingjing

    2013-01-01

    In the field of tissue engineering, polymeric materials with high biocompatibility like polylactic acid and polyglycolic acid have been widely used for fabricating living constructs. For hypopharynx tissue engineering, skeletal muscle is one important functional part of the whole organ, which assembles the unidirectionally aligned myotubes. In this study, a polyurethane (PU) scaffold with microchannel patterns was used to provide aligning guidance for the seeded human myoblasts. Due to the low hydrophilicity of PU, the scaffold was grafted with silk fibroin (PU-SF) or gelatin (PU-Gel) to improve its cell adhesion properties. Scaffolds were observed to degrade slowly over time, and their mechanical properties and hydrophilicities were improved through the surface grafting. Also, the myoblasts seeded on PU-SF had the higher proliferative rate and better differentiation compared with those on the control or PU-Gel. Our results demonstrate that polyurethane scaffolds seeded with myoblasts hold promise to guide hypopharynx muscle regeneration. PMID:24175281

  7. Dynamic Culture Conditions to Generate Silk-Based Tissue-Engineered Vascular Grafts

    PubMed Central

    Zhang, Xiaohui; Wang, Xiuli; Keshav, Vinny; Wang, Xiaoqin; Johanas, Jacqueline; Leisk, Gary; Kaplan, David L

    2009-01-01

    Tissue engineering is an alternative approach for the preparation of small-diameter (<6 mm) vascular grafts due to the potential to control thrombosis, anastomotic cellular hyperplasia and matrix production. This control also requires the maintenance of graft patency in vivo, appropriate mechanical properties and the formation of a functional endothelium. As a first step in generating such tissue-engineered vascular grafts (TEVG), our objective was to develop a tissue-engineered construct that mimicked the structure of blood vessels using tubular electrospun silk fibroin scaffolds (ESFS) with suitable mechanical properties. Human coronary artery smooth muscle cells (HCASMCs) and human aortic endothelial cells (HAECs) were sequentially seeded onto the luminal surface of the tubular scaffolds and cultivated under physiological pulsatile flow. The results demonstrated that TEVGs under dynamic flow conditions had better outcome than static culture controls in terms of cell proliferation and alignment, ECM production and cell phenotype based on transcript and protein level assessments. The metabolic activity of HCASMCs present in the TEGs indicated the advantage of dynamic flow over static culture in effective nutrient and oxygen distribution to the cells. A matrigel coating as a basement membrane mimic for ECM significantly improved endothelium coverage and retention under physiological shear forces. The results demonstrate the successful integration of vascular cells into silk electrospun tubular scaffolds as a step toward the development of a TEVG similar to native vessels in terms of vascular cell outcomes and mechanical properties. PMID:19232717

  8. Osteochondral and Meniscal Allograft Transplantation in the Football (Soccer) Player

    PubMed Central

    Williams, Riley J.; Gersoff, Wayne K.; Bugbee, William D.

    2012-01-01

    Knee injuries are common in football, frequently involving damage to the meniscus and articular cartilage. These injuries can cause significant disability, result in loss of playing time, and predispose players to osteoarthritis. Osteochondral allografting is an increasingly popular treatment option for osteoarticular lesions in athletes. Osteochondral allografts provide mature, orthotopic hyaline cartilage on an osseous scaffold that serves as an attachment vehicle, which is rapidly replaced via creeping substitution, leading to reliable graft integration that allows for simplified rehabilitation and accelerated return to sport. The indications for meniscal replacement in football players are currently still evolving. Meniscus allografts offer potential functional, analgesic, and chondroprotective benefits in the meniscectomized knee. In the player at the end of his or her professional/competitive career, meniscal allografts can play a role in averting progression of chondropenia and facilitating knee function and an active lifestyle. This article is intended to present a concise overview of the limited published results for osteochondral and meniscal allografting in the athletic population and to provide a practical treatment algorithm that is of relevance to the clinician as well as the patient/football player, based on current consensus of opinion. PMID:26069605

  9. Enhancing Osteochondral Allograft Viability: Effects of Storage Media Composition

    PubMed Central

    Teng, Margie S.; Yuen, Audrey S.

    2008-01-01

    Osteochondral allograft transplantation is a well-accepted treatment for articular cartilage damage. However, chondrocyte viability declines during graft storage, which may compromise graft performance. We first tested the hypothesis that the composition of commonly used storage media affects the viability of articular chondrocytes over time; we then tested the hypothesis that the addition of insulin growth factor-1 or the apoptosis inhibitor ZVAD-fmk could enhance the storage properties of serum-free media. Bovine osteochondral grafts were stored at 4°C in lactated Ringer’s, Dulbecco’s modified eagle’s media (DMEM), DMEM supplemented with either insulin growth factor-1 or ZVAD-fmk, and a commercial storage media. Chondrocyte viability in lactated Ringer’s declined rapidly to 20.4% at 2 weeks. Viability in DMEM declined more slowly to 54.8% at 2 weeks and 31.2% at 3 weeks. Viability in commercial storage media was 83.6% at 3 weeks and 44.8% at 4 weeks. Viability was increased in DMEM + insulin growth factor-1 (56.4%) and DMEM + ZVAD (52.4%) at 3 weeks compared with DMEM alone. These results confirm the hypotheses that media composition greatly influences chondrocyte viability during cold storage and that insulin growth factor-1 and ZVAD improve the storage properties of DMEM. PMID:18506560

  10. Enhancing osteochondral allograft viability: effects of storage media composition.

    PubMed

    Teng, Margie S; Yuen, Audrey S; Kim, Hubert T

    2008-08-01

    Osteochondral allograft transplantation is a well-accepted treatment for articular cartilage damage. However, chondrocyte viability declines during graft storage, which may compromise graft performance. We first tested the hypothesis that the composition of commonly used storage media affects the viability of articular chondrocytes over time; we then tested the hypothesis that the addition of insulin growth factor-1 or the apoptosis inhibitor ZVAD-fmk could enhance the storage properties of serum-free media. Bovine osteochondral grafts were stored at 4 degrees C in lactated Ringer's, Dulbecco's modified eagle's media (DMEM), DMEM supplemented with either insulin growth factor-1 or ZVAD-fmk, and a commercial storage media. Chondrocyte viability in lactated Ringer's declined rapidly to 20.4% at 2 weeks. Viability in DMEM declined more slowly to 54.8% at 2 weeks and 31.2% at 3 weeks. Viability in commercial storage media was 83.6% at 3 weeks and 44.8% at 4 weeks. Viability was increased in DMEM + insulin growth factor-1 (56.4%) and DMEM + ZVAD (52.4%) at 3 weeks compared with DMEM alone. These results confirm the hypotheses that media composition greatly influences chondrocyte viability during cold storage and that insulin growth factor-1 and ZVAD improve the storage properties of DMEM. PMID:18506560

  11. Osteochondritis dissecans of the capitellum.

    PubMed

    Baker, Champ L; Romeo, Anthony A; Baker, Champ L

    2010-09-01

    Osteochondritis dissecans of the capitellum is a well-recognized cause of elbow pain and disability in the adolescent athlete. This condition typically affects young athletes, such as throwers and gymnasts, involved in high-demand, repetitive overhead, or weightbearing activities. The true cause, natural history, and optimal treatment of osteochondritis dissecans of the capitellum remain unknown. Suspicion of this condition warrants investigation with proper radiographs and magnetic resonance imaging. Prompt recognition of this disorder and institution of nonoperative treatment for early, stable lesions can result in healing with later resumption of sporting activities. Patients with unstable lesions or those failing nonoperative therapy require operative intervention with treatment based on lesion size and extent. Historically, surgical treatment included arthrotomy with loose body removal and curettage of the residual osteochondral defect base. The introduction of elbow arthroscopy in the treatment of osteochondritis dissecans of the capitellum permits a thorough lesion assessment and evaluation of the entire elbow joint with the ability to treat the lesion and coexistent pathology in a minimally invasive fashion. Unfortunately, the prognosis for advanced lesions remains more guarded, but short-term results after newer reconstruction techniques are promising. PMID:20097927

  12. Gingival Cyst of the Adult as Early Sequela of Connective Tissue Grafting

    PubMed Central

    Gil Escalante, Mariana; Tatakis, Dimitris N.

    2015-01-01

    The subepithelial connective tissue graft (SCTG) is a highly predictable procedure with low complication rate. The reported early complications consist of typical postsurgical sequelae, such as pain and swelling. This case report describes the development and management of a gingival cyst following SCTG to obtain root coverage. Three weeks after SCTG procedure, a slightly raised, indurated, ~5 mm diameter asymptomatic lesion was evident. Excisional biopsy was performed and the histopathological evaluation confirmed the gingival cyst diagnosis. At the 1-year follow-up, the site had complete root coverage and normal tissue appearance and the patient remained asymptomatic. PMID:26236510

  13. Reconstruction of Traumatic Composite Tissue Defect of Medial Longitudinal Arch With Free Osteocutaneous Fibular Graft.

    PubMed

    Unal, Mehmet Bekir; Seker, Ali; Demiralp, Bahtiyar; Sahin, Mustafa; Cift, Hakan Turan; Oltulu, Ismail

    2016-01-01

    A 34-year-old male sustained a crush injury resulting in bone and soft tissue loss along the medial longitudinal arch of his left foot. Specifically, the injury resulted in loss of first metatarsal without injury to the medial cuneiform or proximal phalanx, fracture of the third metatarsal, and a 5-cm × 9-cm soft tissue defect overlying the dorsomedial aspect of the right foot. After debridement and daily wound care, the defect was subsequently reconstructed using a free osteocutaneous fibular graft. Approximately 6 months after reconstructive surgery, the patient returned to his job without pain, and his pedogram showed almost equal weightbearing distribution on both feet. PMID:25459091

  14. Chondrogenesis of Mesenchymal Stem Cells in an Osteochondral Environment Is Mediated by the Subchondral Bone

    PubMed Central

    de Vries–van Melle, Marloes L.; Narcisi, Roberto; Kops, Nicole; Koevoet, Wendy J.L.M.; Bos, P. Koen; Murphy, J. Mary; Verhaar, Jan A.N.; van der Kraan, Peter M.

    2014-01-01

    In articular cartilage repair, cells that will be responsible for the formation of repair tissue are often exposed to an osteochondral environment. To study cartilage repair mechanisms in vitro, we have recently developed a bovine osteochondral biopsy culture model in which cartilage defects can be simulated reproducibly. Using this model, we now aimed at studying the chondrogenic potential of human bone marrow-derived mesenchymal stem cells (hBMSCs) in an osteochondral environment. In contrast to standard in vitro chondrogenesis, it was found that supplementing transforming growth factor beta (TGFβ) to culture medium was not required to induce chondrogenesis of hBMSCs in an osteochondral environment. hBMSC culture in defects created in osteochondral biopsies or in bone-only biopsies resulted in comparable levels of cartilage-related gene expression, whereas culture in cartilage-only biopsies did not induce chondrogenesis. Subcutaneous implantation in nude mice of osteochondral biopsies containing hBMSCs in osteochondral defects resulted in the formation of more cartilaginous tissue than hBMSCs in chondral defects. The subchondral bone secreted TGFβ; however, the observed results could not be attributed to TGFβ, as either capturing TGFβ with an antibody or blocking the canonical TGFβ signaling pathway did not result in significant changes in cartilage-related gene expression of hBMSCs in the osteochondral culture model. Inhibition of BMP signaling did not prevent chondrogenesis. In conclusion, we demonstrate that chondrogenesis of hBMSCs is induced by factors secreted from the bone. We have strong indications that this is not solely mediated by members of the TGFβ family but other, yet unknown, factors originating from the subchondral bone appeared to play a key role. PMID:23980750

  15. The addition of soft tissue replacement grafts in plastic periodontal and implant surgery: critical elements in design and execution.

    PubMed

    Zuhr, Otto; Bäumer, Daniel; Hürzeler, Markus

    2014-04-01

    Soft tissue replacement grafts have become a substantial element to increase tissue volume in plastic periodontal and implant surgery. Autogenous subepithelial connective tissue grafts are increasingly applied in aesthetic indications like soft tissue thickening, recession treatment, ridge preservation, soft tissue ridge augmentation and papilla re-construction. For the clinical performance of connective tissue graft harvesting and transplantation, a fundamental understanding of the anatomy at the donor sites and a sound knowledge of tissue integration and re-vascularization processes are required. Possible donor sites are the anterior and posterior palate including the maxillary tuberosity, providing grafts of distinct geometric shape and histologic composition. The selective clinical application of different grafts depends on the amount of required tissue, the indication and the personal preference of the treating surgeon. One of the main future challenges is to volumetrically evaluate and compare the efficacy and long-term stability of soft tissue autografts and their prospective substitutes. The aim of this review was to discuss the advantages and shortfalls of different donor sites, substitute materials and harvesting techniques. Although standardized recommendations regarding treatment choice and execution can hardly be given, guidelines for predictable and successful treatment outcomes are provided based on clinical experience and the available scientific data. PMID:24640997

  16. Integrating biologically inspired nanomaterials and table-top stereolithography for 3D printed biomimetic osteochondral scaffolds.

    PubMed

    Castro, Nathan J; O'Brien, Joseph; Zhang, Lijie Grace

    2015-09-01

    The osteochondral interface of an arthritic joint is notoriously difficult to regenerate due to its extremely poor regenerative capacity and complex stratified architecture. Native osteochondral tissue extracellular matrix is composed of numerous nanoscale organic and inorganic constituents. Although various tissue engineering strategies exist in addressing osteochondral defects, limitations persist with regards to tissue scaffolding which exhibit biomimetic cues at the nano to micro scale. In an effort to address this, the current work focused on 3D printing biomimetic nanocomposite scaffolds for improved osteochondral tissue regeneration. For this purpose, two biologically-inspired nanomaterials have been synthesized consisting of (1) osteoconductive nanocrystalline hydroxyapatite (nHA) (primary inorganic component of bone) and (2) core-shell poly(lactic-co-glycolic) acid (PLGA) nanospheres encapsulated with chondrogenic transforming growth-factor β1 (TGF-β1) for sustained delivery. Then, a novel table-top stereolithography 3D printer and the nano-ink (i.e., nHA + nanosphere + hydrogel) were employed to fabricate a porous and highly interconnected osteochondral scaffold with hierarchical nano-to-micro structure and spatiotemporal bioactive factor gradients. Our results showed that human bone marrow-derived mesenchymal stem cell adhesion, proliferation, and osteochondral differentiation were greatly improved in the biomimetic graded 3D printed osteochondral construct in vitro. The current work served to illustrate the efficacy of the nano-ink and current 3D printing technology for efficient fabrication of a novel nanocomposite hydrogel scaffold. In addition, tissue-specific growth factors illustrated a synergistic effect leading to increased cell adhesion and directed stem cell differentiation. PMID:26234364

  17. Integrating biologically inspired nanomaterials and table-top stereolithography for 3D printed biomimetic osteochondral scaffolds

    NASA Astrophysics Data System (ADS)

    Castro, Nathan J.; O'Brien, Joseph; Zhang, Lijie Grace

    2015-08-01

    The osteochondral interface of an arthritic joint is notoriously difficult to regenerate due to its extremely poor regenerative capacity and complex stratified architecture. Native osteochondral tissue extracellular matrix is composed of numerous nanoscale organic and inorganic constituents. Although various tissue engineering strategies exist in addressing osteochondral defects, limitations persist with regards to tissue scaffolding which exhibit biomimetic cues at the nano to micro scale. In an effort to address this, the current work focused on 3D printing biomimetic nanocomposite scaffolds for improved osteochondral tissue regeneration. For this purpose, two biologically-inspired nanomaterials have been synthesized consisting of (1) osteoconductive nanocrystalline hydroxyapatite (nHA) (primary inorganic component of bone) and (2) core-shell poly(lactic-co-glycolic) acid (PLGA) nanospheres encapsulated with chondrogenic transforming growth-factor β1 (TGF-β1) for sustained delivery. Then, a novel table-top stereolithography 3D printer and the nano-ink (i.e., nHA + nanosphere + hydrogel) were employed to fabricate a porous and highly interconnected osteochondral scaffold with hierarchical nano-to-micro structure and spatiotemporal bioactive factor gradients. Our results showed that human bone marrow-derived mesenchymal stem cell adhesion, proliferation, and osteochondral differentiation were greatly improved in the biomimetic graded 3D printed osteochondral construct in vitro. The current work served to illustrate the efficacy of the nano-ink and current 3D printing technology for efficient fabrication of a novel nanocomposite hydrogel scaffold. In addition, tissue-specific growth factors illustrated a synergistic effect leading to increased cell adhesion and directed stem cell differentiation.

  18. Characterization of Evolving Biomechanical Properties of Tissue Engineered Vascular Grafts in the Arterial Circulation

    PubMed Central

    Udelsman, Brooks V.; Khosravi, Ramak; Miller, Kristin S.; Dean, Ethan W.; Bersi, Matthew R.; Rocco, Kevin; Yi, Tai; Humphrey, Jay D.; Breuer, Christopher K.

    2014-01-01

    We used a murine model to assess the evolving biomechanical properties of tissue engineered vascular grafts (TEVGs) implanted in the arterial circulation. The initial polymeric tubular scaffold was fabricated from (poly)lactic acid (PLA) and coated with a 50:50 copolymer of (poly)caprolactone and (poly)lactic acid (P[PC/LA]). Following seeding with syngeneic bone marrow derived mononuclear cells, the TEVGs (n=50) were implanted as aortic interposition grafts in wild-type mice and monitored serially using ultrasound. A custom biaxial mechanical testing device was used to quantify in vitro the circumferential and axial mechanical properties of grafts explanted at 3 or 7 months. At both times, the TEVGs were much stiffer than native tissue in both directions. Repeat mechanical testing of some TEVGs treated with elastase or collagenase suggested that elastin did not contribute significantly to the overall stiffness whereas collagen did contribute. Traditional histology and immunostaining revealed smooth muscle cell layers, significant collagen deposition, and increasing elastin production in addition to considerable scaffold at both 3 and 7 months, which likely dominated the high stiffness seen in mechanical testing. These results suggest that PLA has inadequate in vivo degradation, which impairs cell-mediated development of vascular neotissue having properties closer to native arteries. Assessing contributions of individual components, such as elastin and collagen, to the developing neovessel is needed to guide computational modeling that may help to optimize the design of the TEVG. PMID:24702863

  19. Recent Advances in Egypt for Treatment of Talar Osteochondral Lesions.

    PubMed

    Haleem, Amgad M; AbouSayed, Mostafa M; Gomaa, Mohammed

    2016-06-01

    Treatment of osteochondral defects (OCLs) of the talus is a challenging orthopedic surgery. Treatment of talar OCLs has evolved through the 3 "R" paradigm: reconstruction, repair, and replacement. This article highlights current state-of-the-art techniques and reviews recent advances in the literature about articular cartilage repair using various novel tissue engineering approaches, including various scaffolds, growth factors, and cell niches; which include chondrocytes and culture-expanded bone marrow-derived mesenchymal stem cells. PMID:27261813

  20. The innate immune system contributes to tissue-engineered vascular graft performance

    PubMed Central

    Hibino, Narutoshi; Mejias, Dane; Pietris, Nicholas; Dean, Ethan; Yi, Tai; Best, Cameron; Shinoka, Toshiharu; Breuer, Christopher

    2015-01-01

    The first clinical trial of tissue-engineered vascular grafts (TEVGs) identified stenosis as the primary cause of graft failure. In this study, we aimed to elucidate the role of the host immune response in the development of stenosis using a murine model of TEVG implantation. We found that the C.B-17 wild-type (WT) mouse (control) undergoes a dramatic stenotic response, which is nearly completely abolished in the immunodeficient SCID/beige (bg) variant. SCID mice, which lack an adaptive immune system due to the absence of T and B lymphocytes, experienced rates of stenosis comparable to WT controls (average luminal diameter, WT: 0.071 ± 0.035 mm, SCID: 0.137 ± 0.032 mm, SCID/bg: 0.804 ± 0.039 mm; P < 0.001). The bg mutation is characterized by NK cell and platelet dysfunction, and systemic treatment of WT mice with either NK cell–neutralizing (anti–NK 1.1 antibody) or antiplatelet (aspirin/Plavix [clopidogrel bisulfate]; Asp/Pla) therapy achieved nearly half the patency observed in the SCID/bg mouse (NK Ab: 0.356 ± 0.151 mm, Asp/Pla: 0.452 ± 0.130 mm). Scaffold implantation elicited a blunted immune response in SCID/bg mice, as demonstrated by macrophage number and mRNA expression of proinflammatory cytokines in TEVG explants. Implicating the initial innate immune response as a critical factor in graft stenosis may provide a strategy for prognosis and therapy of second-generation TEVGs.—Hibino, N., Mejias, D., Pietris, N., Dean, E., Yi, T., Best, C., Shinoka, T., Breuer, C. The innate immune system contributes to tissue-engineered vascular graft performance. PMID:25713026

  1. Osteochondral Diseases and Fibrodysplasia Ossificans Progressiva

    PubMed Central

    Kaplan, Frederick S.

    2016-01-01

    Osteochondrodysplasias like thanatophoric dysplasia, osteogenesis imperfecta, achondroplasia, and other genetic skeletal disorders like fibrodysplasia ossificans progressiva are infrequently seen in clinical practice. In cases of sporadic achondroplasia as well as in fibrodysplasia ossificans progressiva, there is a strong association with paternal age, a relationship that is less evident in other genetic osteochondral diseases. No other constitutional or environmental factor has proven to be associated with these disorders. The use of prenatal ultrasonography as a routine component of prenatal care is crucial in the early suspicion of osteochondrodysplasias whereas definitive diagnosis is usually obtained by pre-natal molecular analysis. In the case of fibrodysplasia ossificans progressiva, recognition of congenital great toe malformations associated with rapidly–appearing soft tissue swelling is sufficient to make the proper clinical diagnosis, which can be confirmed by genetic testing. Large regional centres will improve diagnosis performance, provide accurate genetic counselling, and ensure an integral assistance for these often severe and incapacitating conditions. PMID:20824454

  2. Osteochondritis dissecans of the talus

    PubMed Central

    ZANON, GIACOMO; DI VICO, GIOVANNI; MARULLO, MATTEO

    2014-01-01

    Osteochondritis dissecans (OCD) is an acquired idiopathic lesion of subchondral bone that can produce delamination and sequestration with or without articular cartilage involvement and instability. The cause of OCD is still debated: the most recognized etiology is the occurrence of repetitive micro-traumas associated with vascular impairment, causing progressive ankle pain and dysfunction in skeletally immature and young adult patients. Ankle OCD is classically located in the medial part of the talus, while lateral and posterior involvement is less frequent. Diagnosis of OCD, based on MRI findings, is quite straightforward; MRI examination can also be very useful for dating the defect and obtaining information about the associated bone bruise. Osteochondritis dissecans, if not recognized and treated appropriately, may lead to secondary osteoarthritis with pain and functional limitation. Surgical treatment is mandatory especially in young patients with unstable cartilage fragments. There are various surgical options: fixation, microfracture, or substitution using autologous chondrocyte implantation techniques. PMID:25606554

  3. Osteochondritis dissecans of the elbow.

    PubMed

    Churchill, Ryan W; Munoz, Julianne; Ahmad, Christopher S

    2016-06-01

    Capitellar osteochondritis dissecans (OCD) can be a significant problem in adolescent overhead athletes. The cause is likely multifactorial secondary to repetitive stresses, biomechanical mismatch, and a tenuous vascular supply of the capitellum. Recent literature reveals that the prevalence is likely higher than previously thought. This, in conjunction with increased levels of athletic competition in children at younger ages, has fed the recent interest in this topic. The literature continues to show that non-operative treatment is still successful for stable lesions. Unstable lesions, therefore, have been the focus of the new literature regarding operative management and outcomes. The aim of this paper is to provide a summary of current literature and an up-to-date approach to the diagnosis, evaluation, and treatment of osteochondritis dissecans of the capitellum. PMID:27125506

  4. Collagen structural alterations contribute to stiffening of tissue after split-thickness skin grafting.

    PubMed

    Rosin, Nicole L; Agabalyan, Natacha; Olsen, Katherine; Martufi, Giampaol; Gabriel, Vincent; Biernaskie, Jeff; Di Martino, Elena S

    2016-03-01

    The gold standard treatment for full thickness injuries of the skin is autologous split-thickness skin grafting. This involves harvesting the epidermis and superficial dermis from healthy skin and transplanting it onto the prepared wound bed. The donor site regenerates spontaneously, but the appendages and cellular components from the dermal layer are excluded from the graft. As a result, the new tissue is inferior; the healed graft site is dry/itchy, has decreased elasticity, increased fragility, and altered sensory function. Because this dermal layer is composed of collagen and other extracellular matrix proteins, the aim was to characterize the changes in the dermal collagen after split thickness grafting that could contribute to a deficit in functionality. This will serve as a baseline for future studies designed to improve skin function using pharmacological or cell-based therapies for skin repair. A xenograft model whereby human split-thickness grafts were implanted into full-thickness defects on immunocompromised (athymic Nu/Nu) mice was used. The grafts were harvested 4 and 8 weeks later. The collagen microstructure was assessed with second harmonic generation with dual-photon microscopy and light polarization analysis. Collagen fiber stiffness and engagement stretch were estimated by fitting the results of biaxial mechanical tensile tests to a histo-mechanical constitutive model. The stiffness of the collagen fibril-proteoglycan complex increased from 682 ± 226 kPa/sr to 1016 ± 324 kPa/sr between 4 and 8 weeks postgrafting. At the microstructural level there were significant decreases in both thickness of collagen fibers (3.60 ± 0.34 μm vs. 2.10 ± 0.27 μm) and waviness ratio (2.04 ± 0.17 vs. 1.43 ± 0.08) of the collagen fibers postgrafting. The decrease of the macroscopic engagement stretch from 1.19 ± 0.11 to 1.09 ± 0.08 over time postgrafting mirrored the decrease in waviness measured at the microscopic level

  5. Alveolar Ridge Contouring with Free Connective Tissue Graft at Implant Placement: A 5-Year Consecutive Clinical Study.

    PubMed

    Hanser, Thomas; Khoury, Fouad

    2016-01-01

    This study evaluated volume stability after alveolar ridge contouring with free connective tissue grafts at implant placement in single-tooth gaps. A total of 52 single-tooth gaps with labial volume deficiencies in the maxilla (incisors, canines, and premolars) were consecutively treated with implants and concomitant free palatal connective tissue grafts in 46 patients between 2006 and 2009. Implants had to be covered with at least 2 mm peri-implant local bone after insertion. At implant placement, a free connective tissue graft from the palate was fixed inside a labial split-thickness flap to form an existing concave buccal alveolar ridge contour due to tissue volume deficiency into a convex shape. Standardized volumetric measurements of the labial alveolar contour using a template were evaluated before connective tissue grafting and at 2 weeks, 1 year, and 5 years after implantprosthetic incorporation. Tissue volume had increased significantly (P < .05) in all six reference points representing the outer alveolar soft tissue contour of the implant before connective tissue grafting to baseline (2 weeks after implant-prosthetic incorporation). Statistically, 50% of the reference points (P > .05) kept their volume from baseline to 1 year after prosthetic incorporation and from baseline to 5 years after prosthetic incorporation, respectively, whereas reference points located within the area of the implant sulcus showed a significant (P < .05) decrease in volume. Clinically, 5 years after prosthetic incorporation the originally concave buccal alveolar contour was still convex in all implants, leading to a continuous favorable anatomical shape and improved esthetic situation. Intraoral radiographs confirmed osseointegration and stable peri-implant parameters with a survival rate of 100% after a follow-up of approximately 5 years. Implant placement with concomitant free connective tissue grafting appears to be an appropriate long-term means to contour preexisting buccal

  6. Computationally Optimizing the Compliance of a Biopolymer Based Tissue Engineered Vascular Graft.

    PubMed

    Harrison, Scott; Tamimi, Ehab; Uhlorn, Josh; Leach, Tim; Vande Geest, Jonathan P

    2016-01-01

    Coronary heart disease is a leading cause of death among Americans for which coronary artery bypass graft (CABG) surgery is a standard surgical treatment. The success of CABG surgery is impaired by a compliance mismatch between vascular grafts and native vessels. Tissue engineered vascular grafts (TEVGs) have the potential to be compliance matched and thereby reduce the risk of graft failure. Glutaraldehyde (GLUT) vapor-crosslinked gelatin/fibrinogen constructs were fabricated and mechanically tested in a previous study by our research group at 2, 8, and 24 hrs of GLUT vapor exposure. The current study details a computational method that was developed to predict the material properties of our constructs for crosslinking times between 2 and 24 hrs by interpolating the 2, 8, and 24 hrs crosslinking time data. matlab and abaqus were used to determine the optimal combination of fabrication parameters to produce a compliance matched construct. The validity of the method was tested by creating a 16-hr crosslinked construct of 130 μm thickness and comparing its compliance to that predicted by the optimization algorithm. The predicted compliance of the 16-hr construct was 0.00059 mm Hg-1 while the experimentally determined compliance was 0.00065 mm Hg-1, a relative difference of 9.2%. Prior data in our laboratory has shown the compliance of the left anterior descending porcine coronary (LADC) artery to be 0.00071 ± 0.0003 mm Hg-1. Our optimization algorithm predicts that a 258-μm-thick construct that is GLUT vapor crosslinked for 8.1 hrs would match LADC compliance. This result is consistent with our previous work demonstrating that an 8-hr GLUT vapor crosslinked construct produces a compliance that is not significantly different from a porcine coronary LADC. PMID:26593773

  7. 3D printing of novel osteochondral scaffolds with graded microstructure.

    PubMed

    Nowicki, Margaret A; Castro, Nathan J; Plesniak, Michael W; Zhang, Lijie Grace

    2016-10-14

    Osteochondral tissue has a complex graded structure where biological, physiological, and mechanical properties vary significantly over the full thickness spanning from the subchondral bone region beneath the joint surface to the hyaline cartilage region at the joint surface. This presents a significant challenge for tissue-engineered structures addressing osteochondral defects. Fused deposition modeling (FDM) 3D bioprinters present a unique solution to this problem. The objective of this study is to use FDM-based 3D bioprinting and nanocrystalline hydroxyapatite for improved bone marrow human mesenchymal stem cell (hMSC) adhesion, growth, and osteochondral differentiation. FDM printing parameters can be tuned through computer aided design and computer numerical control software to manipulate scaffold geometries in ways that are beneficial to mechanical performance without hindering cellular behavior. Additionally, the ability to fine-tune 3D printed scaffolds increases further through our investment casting procedure which facilitates the inclusion of nanoparticles with biochemical factors to further elicit desired hMSC differentiation. For this study, FDM was used to print investment-casting molds innovatively designed with varied pore distribution over the full thickness of the scaffold. The mechanical and biological impacts of the varied pore distributions were compared and evaluated to determine the benefits of this physical manipulation. The results indicate that both mechanical properties and cell performance improve in the graded pore structures when compared to homogeneously distributed porous and non-porous structures. Differentiation results indicated successful osteogenic and chondrogenic manipulation in engineered scaffolds. PMID:27606933

  8. Hard tissue remodeling using biofabricated coralline biomaterials.

    PubMed

    Vago, Razi; Plotquin, Daniel; Bunin, Alex; Sinelnikov, Igor; Atar, Dan; Itzhak, David

    2002-01-01

    Biotechnical and biomedical approaches were combined in an attempt to identify potential uses of biofabricated marine carbonate materials in biomedical applications, particularly as biomatrices for remodeling bone and cartilage tissue. After grafting, it is desirable for bone ingrowth to proceed as quickly as possible because the strength of the implanted region depends on a good mechanical bond forming between the implant and surrounding regions in the body. Ingrowth can take place as a result of growth of tissue and cells into the implanted porous material, or it may be promoted by transplanting cells seeded onto such a material. The rate at which ingrowth occurs is dependent on many factors, including pore size and the interconnectivity of the implanted structure. In vivo graftings into osteochondral defects demonstrated that our biofabricated porous material is highly biocompatible with cartilage and bone tissue. The biofabricated matrix was well incorporated into the biphasic osteochondral area. Resorption was followed by bone and cartilage formation, and after 4 months, the biomaterial had been replaced by new tissue. Ossification was induced and enhanced without introduction of additional factors. We believe that this is the first time that such biofabricated materials have been used for biomedical purposes. In face of the obvious environmental disadvantages of harvesting from limited natural resources, we propose the use of bioengineered coralline and other materials such as those cultured by our group under field and laboratory conditions as a possible biomatrix for hard tissue remodeling. PMID:11741712

  9. Guided tissue regeneration and bone grafts in the treatment of furcation defects.

    PubMed

    Caffesse, R G; Nasjleti, C E; Plotzke, A E; Anderson, G B; Morrison, E C

    1993-11-01

    The present study evaluated the effects of guided tissue regeneration (GTR), with and without demineralized freeze-dried cortical bone grafts, in the treatment of furcation defects in 4 female beagle dogs with naturally occurring periodontal disease. The root surfaces were thoroughly debrided. Four weeks later, full thickness facial and lingual mucoperiosteal flaps were reflected using inverse bevel incisions on both sides of the mandible involving the 2nd, 3rd, and 4th premolar, and the 1st molar teeth. Following debridement, notches were placed on the roots at the level of supporting bone. Test quadrants were randomly selected and furcations were filled with reconstituted, demineralized, freeze-dried human cortical bone grafts. Following bone grafting, all defects were covered with an expanded polytetrafluoroethylene (ePTFE) membrane, which was sutured with 4-0 sutures. Afterward, interproximal sutures were placed through the flaps, assuring the flaps covered the membranes completely. The contralateral side, serving as control, was treated by debridement only and application of ePTFE membrane. All membranes were removed 6 weeks after surgery. Dogs were sacrificed at 4 months after surgery. Both mesio-distal and bucco-lingual histologic sections were evaluated by descriptive histology. Linear measurements and surface area determination of the furcal tissues were carried out using the microscope attached to a digitizer. Twelve to 20 nonserial sections were made of the mid-buccal aspects of each root of each treated tooth. Half of these sections were stained with Harris' hematoxylin and eosin (H&E) and the other half stained with Mallory's trichrome stain.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8295103

  10. Repair of lacerated anterior tibial tendon with acellular tissue graft augmentation.

    PubMed

    DiDomenico, Lawrence A; Blasko, Gregory A; Cane, Laurence; Cross, Davina J

    2012-01-01

    In the present case report, we describe the surgical repair of a complete laceration of the anterior tibial tendon using acellular human dermal tissue matrix. A 17-year-old, elite league hockey player was injured in the locker room when a teammate still clad in ice skates stepped on his bare left foot. After evaluation at a local emergency department, the patient presented to our office the next day for additional evaluation. It was determined that surgery would be performed using acellular tissue graft augmentation, followed by physical therapy. Within 7 weeks of the injury, the athlete returned to his original level of activity. At 3 years of follow-up, he was playing Division 1 hockey at the university level. We believe that augmentation of the tendon repair with the grafting material enhanced the tendon tensile strength and promoted ingrowth through vascular channels. This, combined with the patient's dedication to physical therapy, led to excellent recovery in less time than anticipated. PMID:22762944

  11. A preliminary study on the effects of acellular tissue graft augmentation in acute Achilles tendon ruptures.

    PubMed

    Lee, Daniel K

    2008-01-01

    Acute Achilles tendon rupture injuries present surgical challenges because of the mechanical forces placed on this tendon. The purpose of this study was to evaluate the effectiveness of an acellular human dermal tissue matrix, GraftJacket Matrix (Wright Medical Technology, Inc., Arlington, TN), as an augmentation material in acute Achilles tendon repair. Eleven consecutive patients with acute tendon ruptures were evaluated and followed up (20-31 months). Primary repair was followed by augmentation with the graft sutured circumferentially around the tendon. Patients were placed in an early functional rehabilitation program with postoperative evaluation at 3, 6, and 12 months. Outcome scores were calculated based on the American Orthopaedic Foot and Ankle Society ankle-hindfoot scoring system. At 20-month postoperative follow-up, there have been no cases of rerupture or recurrent pain. The average return-to-activity time was 11.8 +/- 0.75 weeks. These retrospective clinical results suggest that with an acellular human dermal tissue matrix to augment acute Achilles tendon, primary repair offers a desirable return-to-activity time without any rerupture or complications. ACFAS Level of Clinical Evidence: 2c. PMID:18156058

  12. Soft Tissue Reconstruction with Free Gingival Graft Technique following Excision of a Fibroma

    PubMed Central

    Tezci, Nurcan; Meseli, Suleyman Emre; Karaduman, Burcu; Dogan, Serap; Meric, Sabri Hasan

    2015-01-01

    Background. Oral fibromas are benign, asymptomatic, smooth surfaced, firm structured tumoral lesions that originate from gingival connective tissue or periodontal ligament. Histologically, they are nodular masses characterized by a dense connective tissue, surrounded by stratified squamous epithelium. Case Report. This case report includes the clinical, radiographical, and histological findings and periodontal treatment of a 38-year-old female patient having painless swelling on the gingiva. Intraoral examination revealed a fibrotic, sessile, smooth surfaced gingival overgrowth interdentally between the teeth #13 and #14. Radiographical findings were normal. Initial periodontal treatment (IPT) was applied including oral hygiene instructions, scaling, and root planing. Following IPT, the lesion (0.7 × 0.6 × 0.4 cm) was excised and examined histopathologically. Subsequently, flap operation was performed to have an access to alveolar bone. Surgical site was reconstructed with free gingival graft obtained from hard palate. Hematoxylin-eosin stained sections revealed a nodular mass composed by dense collagen fibers in lamina propria covered by a stratified squamous epithelium, which were consistent with fibroma. Gingival healing was uneventful and without any recurrence during the 12-month follow-up. Conclusions. In order to achieve optimal functional and aesthetical outcomes, free gingival graft can be used for the reconstruction of the wound site after the excision of the fibroma. PMID:26357576

  13. Structural hierarchy of biomimetic materials for tissue engineered vascular and orthopedic grafts.

    PubMed

    Lekakou, C; Lamprou, D; Vidyarthi, U; Karopoulou, E; Zhdan, P

    2008-05-01

    Gelatine gels and gelatine/elastin gels have been prepared to be used in tissue engineered vascular grafts. Optical microscopy and atomic force microscopy (AFM) revealed that the gelatine formed nanofibrils as in soft collagen tissues. The gelatine/elastin gels were nanocomposites with flat elastin nanodomains embedded in the gelatine matrix mimicking the structure of the tunica media in arteries. Gelatine/"hydroxyapatite" (HA) nanocomposites were prepared with the in situ production of "HA" in solution. AFM revealed "HA" solid nanoparticles of about 20 nm size embedded in the gelatine matrix, which formed a hierarchical structure similar to that of the collagen matrix in bone. The application of amagnetic field of 9.4 T resulted in the elongation and orientation of gelatine particles and orientation of gelatine microfibrils in a direction perpendicular to that of the magnetic field. (c) 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008. PMID:18098204

  14. Subpedicle connective tissue graft versus guided tissue regeneration with bioabsorbable membrane in the treatment of human gingival recession defects.

    PubMed

    Trombelli, L; Scabbia, A; Tatakis, D N; Calura, G

    1998-11-01

    The purpose of the present clinical study was to evaluate the effect of guided tissue regeneration (GTR) in comparison to subpedicle connective tissue graft (SCTG) in the treatment of gingival recession defects. A total of 12 patients, each contributing a pair of Miller's Class I or II buccal gingival recessions, was treated. According to a randomization list, one defect in each patient received a polyglycolide/lactide bioabsorbable membrane, while the paired defect received a SCTG. Treatment effect was evaluated 6 months postsurgery. Clinical recordings included full-mouth and defect-specific oral hygiene standards and gingival health, recession depth (RD), recession width (RW), probing depth (PD), clinical attachment level (CAL), and keratinized tissue width (KT). Mean RD significantly decreased from 3.1 mm presurgery to 1.5 mm at 6 months postsurgery for the GTR group (48% root coverage), and from 3.0 mm to 0.5 mm for the SCTG group (81% root coverage). RD reduction and root coverage were significantly greater in SCTG group compared to GTR group. Mean CAL gain amounted to 1.7 mm for the GTR group, and 2.3 mm in the SCTG group. No significant differences in PD changes were observed within and between groups. KT increased significantly from presurgery for both treatment groups, however gingival augmentation was significantly greater in the SCTG group compared to GTR group. Results indicate that: 1) treatment of human gingival recession defects by means of both GTR and SCTG procedures results in clinically and statistically significant improvement of the soft tissue conditions of the defect; and 2) treatment outcome was significantly better following SCTG compared to GTR in terms of recession depth reduction, root coverage, and keratinized tissue increase. PMID:9848537

  15. Clinical evaluation of subepithelial connective tissue graft and guided tissue regeneration for treatment of Miller’s class 1 gingival recession (comparative, split mouth, six months study)

    PubMed Central

    Bhavsar, Neeta-V.; Dulani, Kirti; Trivedi, Rahul

    2014-01-01

    Objectives: The present study aims to clinically compare and evaluate subepithelial connective tissue graft and the GTR based root coverage in treatment of Miller’s Class I gingival recession. Study Design: 30 patients with at least one pair of Miller’s Class I gingival recession were treated either with Subepithelial connective tissue graft (Group A) or Guided tissue regeneration (Group B). Clinical parameters monitored included recession RD, width of keratinized gingiva (KG), probing depth (PD), clinical attachment level (CAL), attached gingiva (AG), residual probing depth (RPD) and % of Root coverage(%RC). Measurements were taken at baseline, three months and six months. A standard surgical procedure was used for both Group A and Group B. Data were recorded and statistical analysis was done for both intergroup and intragroup. Results: At end of six months % RC obtained were 84.47% (Group A) and 81.67% (Group B). Both treatments resulted in statistically significant improvement in clinical parameters. When compared, no statistically significant difference was found between both groups except in RPD, where it was significantly greater in Group A. Conclusions: GTR technique has advantages over subepithelial connective tissue graft for shallow Miller’s Class I defects and this procedure can be used to avoid patient discomfort and reduce treatment time. Key words:Collagen membrane, comparative split mouth study, gingival recession, subepithelial connective tissue graft, guided tissue regeneration (GTR). PMID:25136420

  16. Clinical Comparison of Full and Partial Double Pedicle Flaps with Connective Tissue Grafts for Treatment of Gingival Recession

    PubMed Central

    Ranjbari, Ardeshir; Gholami, Gholam Ali; Amid, Reza; Kadkhodazadeh, Mahdi; Youssefi, Navid; Mehdizadeh, Amir Reza; Aghaloo, Maryam

    2016-01-01

    Statement of the Problem Gingival recession has been considered as the most challenging issue in the field of periodontal plastic surgery. Purpose The purpose of this study was to evaluate the clinical efficacy of root coverage procedures by using partial thickness double pedicle graft and compare it with full thickness double pedicle graft. Materials and Method Eight patients, aged 15 to 58 years including 6 females and 2 males with 20 paired (mirror image) defects with class I and II gingival recession were randomly assigned into two groups. Clinical parameters such as recession depth, recession width, clinical attachment level, probing depth, and width of keratinized tissue were measured at the baseline and 6 months post-surgery. A mucosal double papillary flap was elevated and the respective root was thoroughly planed. The connective tissue graft was harvested from the palate, and then adapted over the root. The pedicle flap was secured over the connective tissue graft and sutured. The surgical technique was similar in the control group except for the prepared double pedicle graft which was full thickness. Results The mean root coverage was 88.14% (2.83 mm) in the test group and 85.7% (2.75 mm) in the control group. No statistical differences were found in the mean reduction of vertical recession, width of recession, or probing depth between the test and control groups. In both procedures, the width of keratinized tissue increased after three months and the difference between the two groups was not statistically significant in this respect. Conclusion Connective tissue with partial and full thickness double pedicle grafts can be successfully used for treatment of marginal gingival recession. PMID:27602394

  17. Hybrid Matrix Grafts to Favor Tissue Regeneration in Rabbit Femur Bone Lesions

    PubMed Central

    Goy, Dante Pascual; Gorosito, Emmanuel; Costa, Hermes S; Mortarino, Pablo; Pedemonte, Noelia Acosta; Toledo, Javier; Mansur, Herman S; Pereira, Marivalda M; Battaglino, Ricardo; Feldman, Sara

    2012-01-01

    At present, typical approaches employed to repair fractures and other bone lesions tend to use matrix grafts to promote tissue regeneration. These grafts act as templates, which promote cellular adhesion, growth and proliferation, osteoconduction, and even osteoinduction, which commonly results in de novo osteogenesis. The present work aimed to study the bone-repairing ability of hybrid matrixes (HM) prepared with polyvinyl alcohol (PVA) and bioactive glass in an experimental rabbit model. The HM were prepared by combining 30% bioactive glass (nominal composition of 58% SiO2 -33 % CaO - 9% P2O5) and 70% PVA. New Zealand rabbits were randomly divided into the control group (C group) and two groups with bone lesions, in which one received a matrix implant HM (Implant group), while the other did not (no Implant group). Clinical monitoring showed no altered parameters from either the Implant or the no Implant groups as compared to the control group, for the variables of diet grades, day and night temperatures and hemograms. In the Implant group, radiologic and tomographic studies showed implanted areas with clean edges in femoral non-articular direction, and radio-dense images that suggest incipient integration. Minimum signs of phlogosis could be observed, whereas no signs of rejection at this imaging level could be identified. Histological analysis showed evidence of osteo-integration, with the formation of a trabecular bone within the implant. Together, these results show that implants of hybrid matrixes of bioactive glass are capable of promoting bone regeneration. PMID:22848334

  18. Sporicidal efficacy of genipin: a potential theoretical alternative for biomaterial and tissue graft sterilization.

    PubMed

    Reich, Michael S; Akkus, Ozan

    2013-09-01

    Terminal sterilization of musculoskeletal allografts by gamma radiation minimizes the risk of disease transmission but impairs allograft mechanical properties. Commonly employed crosslinking agents can sterilize tissues without affecting mechanical properties adversely; however, these agents are toxic. Genipin is reported to be a benign crosslinking agent that strengthens mechanical properties of tissues; however, the antimicrobial capacity of genipin is largely unknown. The present study's aims were: (1) to assess the sporicidal potential of genipin, (2) to improve antimicrobial capacity by changing chemical and physical treatment conditions. To establish genipin's sterilization potential Bacillus subtilis var. niger spore strips were treated with 0-10% genipin in PBS or in 1:1 DMSO:PBS up to 72 h at room temperature (RT). Sterilizing doses and concentrations of genipin were used to treat B. pumilus and Geobacillus stearothermophilus spores to assess broader spectrum sporicidal activity of genipin. Scanning electron microscopy (SEM) was performed to evaluate gross morphological changes after genipin treatment. Optimal sterilization conditions were determined by evaluating the effects of temperature (RT-50 °C), DMSO:PBS ratio (0:100-100:0), and treatment duration (24-72 h) on B. subtilis. Genipin penetration of full thickness bovine patellar tendon and cortical bone specimens was observed to assess the feasibility of the agent for treating grafts. Initial studies showed that after 72 h of treatment at RT with 0.63-10% genipin/DMSO:PBS B. subtilis spore strips were sterilized; 0.63% genipin/PBS did not sterilize spore strips at 72 h at RT. Genipin doses and concentrations that sterilized B. subtilis spore strips sterilized B. pumilus and G. stearothermophilus spore strips. SEM revealed no gross morphological differences between untreated and treated spores. Treatment optimization resulted in sterilization within 24 h with 100% PBS, and DMSO facilitated sporicidal

  19. Electrospinning of aniline pentamer-graft-gelatin/PLLA nanofibers for bone tissue engineering.

    PubMed

    Liu, Yadong; Cui, Haitao; Zhuang, Xiuli; Wei, Yen; Chen, Xuesi

    2014-12-01

    Blends of aniline pentamer-graft-gelatin (AP-g-GA) and poly(l-lactide) (PLLA) were electrospun to prepare uniform nanofibers as biomimetic scaffolds. The nanofibers exhibited good electroactivity, thermal stability and biodegradability. The biocompatibility of the nanofibers in vitro was evaluated by the adhesion and proliferation of mouse preosteoblastic MC3T3-E1 cells. The cellular elongation was significantly greater on electroactive AP-g-GA/PLLA nanofibers than on PLLA nanofibers. Moreover, the AP-g-GA/PLLA nanofibers stimulated by an electrical pulsed signal could promote the differentiation of MC3T3-E1 cells compared with pure PLLA nanofibers. Our results demonstrated that the biodegradable and electroactive AP-g-GA/PLLA nanofibers had potential application in vivo as bone repair scaffold materials in tissue engineering. PMID:25200841

  20. Analysis of cell-tissue grafts under weightless conditions using confocal fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Volova, L. T.; Milyakova, M. N.; Rossinskaya, V. V.; Boltovskaya, V. V.; Kulagina, L. N.; Kurganskaya, L. V.; Timchenko, P. E.; Timchenko, E. V.; Zherdeva Taskina, Larisa A.

    2015-03-01

    The research results of monitoring of viable cells in a cellular-tissue graft using confocal laser fluorescence microscopy at 488 nm and 561 nm with the use of fluorophore propidium iodide (propidium iodide, PI Sigma Aldrich USA) are presented. The processing of the received images was carried out using the software ANDOR. It is experimentally shown that the method of confocal fluorescence microscopy is one of the informational methods for detecting cells populated in a 3-D bio-carrier with a resolution of at least 400 nm. Analysis of the received micrographs suggests that the cells that were in a bio-carrier for 30 days in a synchronous ground-based experiment retained their viability compared to a similar space-based experiment in which the cells were hardly detected in a bio-carrier.

  1. Decellularized ureter for tissue-engineered small-caliber vascular graft.

    PubMed

    Narita, Yuji; Kagami, Hideaki; Matsunuma, Hiroshi; Murase, Yosuke; Ueda, Minoru; Ueda, Yuichi

    2008-01-01

    Previous attempts to create small-caliber vascular prostheses have been limited. The aim of this study was to generate tissue-engineered small-diameter vascular grafts using decellularized ureters (DUs). Canine ureters were decellularized using one of four different chemical agents [Triton-X 100 (Tx), deoxycholate (DCA), trypsin, or sodium dodecyl sulfate (SDS)] and the histology, residual DNA contents, and immunogenicity of the resulting DUs were compared. The mechanical properties of the DUs were evaluated in terms of water permeability, burst strength, tensile strength, and compliance. Cultured canine endothelial cells (ECs) and myofibroblasts were seeded onto DUs and evaluated histologically. Canine carotid arteries were replaced with the EC-seeded DUs (n = 4). As controls, nonseeded DUs (n = 5) and PTFE prostheses (n = 4) were also used to replace carotid arteries. The degree of decellularization and the maintenance of the matrix were best in the Tx-treated DUs. Tx-treated and DCA-treated DUs had lower remnant DNA contents and immunogenicity than the others. The burst strength of the DUs was more than 500 mmHg and the maximum tensile strength of the DUs was not different to that of native ureters. DU compliance was similar to that of native carotid artery. The cell seeding test resulted in monolayered ECs and multilayered alpha-smooth muscle actin-positive cells on the DUs. The animal implantation model showed that the EC-seeded DUs were patent for at least 6 months after the operation, whereas the nonseeded DUs and PTFE grafts become occluded within a week. These results suggest that tissue-engineered DUs may be a potential alternative conduit for bypass surgery. PMID:18604613

  2. Achilles tendon repair with acellular tissue graft augmentation in neglected ruptures.

    PubMed

    Lee, Daniel K

    2007-01-01

    Neglected Achilles tendon rupture injuries present surgical challenges because of the quality and quantity of tendon tissue during repair combined with the magnitude of mechanical forces placed on this tendon. The purpose of this study was to evaluate the effects of an acellular human dermal tissue matrix, GRAFTJACKET, as an augmentation material in neglected Achilles tendon repair. Nine patients with neglected Achilles tendon ruptures were evaluated and followed up for a minimum of 20 months. Primary repair was followed by augmentation with the graft and suturing circumferentially around the tendon. Patients were placed in an early, functional rehabilitation program with postoperative evaluation at 3, 6, and 12 months. Outcome scores were calculated based on the American Orthopaedic Foot and Ankle Society ankle-hindfoot scoring system. At 20 to 30 months postoperative follow-up range, there has been no incidence of re-rupture or recurrent pain. The average return-to-activity time was 15.2 +/- 1.7 weeks. The results from this retrospective clinical series suggest that using an acellular human dermal tissue matrix to augment neglected Achilles tendon rupture primary repair offers desirable return-to-activity time points and viable surgical alternative over previously reported surgical options. PMID:17980842

  3. Influence of intra-articular administration of trichostatin a on autologous osteochondral transplantation in a rabbit model.

    PubMed

    Hou, Huacheng; Zheng, Ke; Wang, Guanghu; Ikegawa, Shiro; Zheng, Minghao; Gao, Xiang; Qin, Jinzhong; Teng, Huajian; Jiang, Qing

    2015-01-01

    Autologous osteochondral transplantation (AOT) is a method for articular cartilage repair. However, several disadvantages of this method have been reported, such as transplanted cartilage degeneration and the lack of a connection between the grafted and adjacent cartilage tissues. To evaluate the effect of intra-articular administration of trichostatin A (TSA) on AOT, we conducted a case control study in a rabbit model. International Cartilage Repair Society (ICRS) macroscopic scores, the modified O'Driscoll histology scores, and real-time PCR were utilized to evaluate the results. At 4 weeks, both macroscopic and histological assessments showed that there was no significant difference between the TSA and control groups. However, the mean macroscopic and histological scores for the TSA-treated group were significantly higher than the scores for the control group at 12 weeks. TSA was shown to directly reduce collagen type II (COL2), aggrecan, matrix metalloproteinase (MMP), and a disintegrin and metalloproteinase domain with thrombospondin motifs 5 (ADAMTS-5) expression and to simultaneously repress the upregulation of MMP-3, MMP-9, and MMP-13 levels induced by interleukin 1β (IL-1β) in chondrocytes. In conclusion, TSA protects AOT grafts from degeneration, which may provide a benefit in the repair of articular cartilage injury. PMID:25866784

  4. Human Mesenchymal Stem Cell Grafts Enhance Normal and Impaired Wound Healing by Recruiting Existing Endogenous Tissue Stem/Progenitor Cells

    PubMed Central

    Shin, Laura

    2013-01-01

    Mesenchymal stem cells (MSCs) have been investigated as a clinical therapy to promote tissue repair. However, the disappearance of grafted cells soon after engraftment suggests a possible role as initiators of repair rather than effectors. We evaluated the relative contribution of grafted human MSCs and host stem/progenitor cells in promoting wound healing by using a novel asymmetric wound model in normal and impaired healing diabetic (db/db) mice to discriminate between the effect of direct engraftment and the subsequent systemic response. Experimental animals received paired wounds, with one wound receiving human mesenchymal stem cells (hMSCs) and the other wound receiving vehicle to assess local and systemic effects, respectively. Control animals received vehicle in both wounds. Grafted hMSCs significantly improved healing in both normal and impaired healing animals; produced significant elevation of signals such as Wnt3a, vascular endothelial growth factor, and platelet-derived growth factor receptor-α; and increased the number of pre-existing host MSCs recruited to the wound bed. Improvement was also seen in both the grafted and nongrafted sides, suggesting a systemic response to hMSC engraftment. Healing was enhanced despite the rapid loss of hMSCs, suggesting that mobilizing the host response is the major outcome of grafting MSCs to tissue repair. We validate that hMSCs evoke a host response that is clinically relevant, and we suggest that therapeutic efforts should focus on maximizing the mobilization of host MSCs. PMID:23283490

  5. Effect of Autogenous Cortical Bone Grafting in Conjunction with Guided Tissue Regeneration in the Treatment of Intraosseous Periodontal Defects

    PubMed Central

    Keles, Gonca Cayir; Sumer, Mahmut; Cetinkaya, Burcu Ozkan; Tutkun, Ferda; Simsek, S. Burcak

    2010-01-01

    Objectives: The aim of this clinical trial was to evaluate the additional benefit of using guided tissue regeneration (GTR) with autogenous cortical bone (ACB) grafting versus ACB grafting alone for the regenerative treatment of intraosseous periodontal defects. Methods: Via a split-mouth design, 12 patients with chronic periodontitis (five men, seven women; mean age, 45.3±4.6 years) who had probing pocket depths (PPDs) of ≥6 mm following initial periodontal therapy were randomly assigned to two treatments in contralateral areas of the dentition: a combination of ACB grafting and GTR (with a absorbable membrane of polylactic acid) or ACB grafting alone. The compared parameters were preoperative and 6-month postoperative PPDs, clinical attachment levels (CALs), and radiographic alveolar bone heights. Results: Both treatment modalities resulted in significant changes in the postoperative measurements from the preoperative values (P<.01). The reduction in the PPDs, gain in the CALs, and gain in the radiographic alveolar bone heights were 4.58±1.08, 4.25±1.06, and 5.50±2.24 mm in the patients treated with ACB grafting and GTR and 4.92±1.00, 4.50±0.80, and 5.92±1.83 mm in those treated with ACB grafting alone, respectively. The differences between the treatments were not statistically significant (P>.05). Conclusions: Within the study limitations, both ACB grafting with GTR and ACB grafting alone lead to significant improvements in clinical and radiographic parameters at 6 months postoperatively. The combined approach does not provide any additional benefit for treating intraosseous periodontal defects. PMID:20922160

  6. Genetics Home Reference: familial osteochondritis dissecans

    MedlinePlus

    ... Gentili C, Cancedda R. Cartilage and bone extracellular matrix. Curr Pharm Des. 2009;15(12):1334-48. ... the aggrecan C-type lectin domain disrupts extracellular matrix interactions and causes dominant familial osteochondritis dissecans. Am ...

  7. Repair and regeneration of osteochondral defects in the articular joints.

    PubMed

    Swieszkowski, Wojciech; Tuan, Barnabas Ho Saey; Kurzydlowski, Krzysztof J; Hutmacher, Dietmar W

    2007-11-01

    People suffering from pain due to osteoarthritic or rheumatoidal changes in the joints are still waiting for a better treatment. Although some studies have achieved success in repairing small cartilage defects, there is no widely accepted method for complete repair of osteochondral defects. Also joint replacements have not yet succeeded in replacing of natural cartilage without complications. Therefore, there is room for a new medical approach, which outperforms currently used methods. The aim of this study is to show potential of using a tissue engineering approach for regeneration of osteochondral defects. The critical review of currently used methods for treatment of osteochondral defects is also provided. In this study, two kinds of hybrid scaffolds developed in Hutmacher's group have been analysed. The first biphasic scaffold consists of fibrin and PCL. The fibrin serves as a cartilage phase while the porous PCL scaffold acts as the subchondral phase. The second system comprises of PCL and PCL-TCP. The scaffolds were fabricated via fused deposition modeling which is a rapid prototyping system. Bone marrow-derived mesenchymal cells were isolated from New Zealand White rabbits, cultured in vitro and seeded into the scaffolds. Bone regenerations of the subchondral phases were quantified via micro CT analysis and the results demonstrated the potential of the porous PCL and PCL-TCP scaffolds in promoting bone healing. Fibrin was found to be lacking in this aspect as it degrades rapidly. On the other hand, the porous PCL scaffold degrades slowly hence it provides an effective mechanical support. This study shows that in the field of cartilage repair or replacement, tissue engineering may have big impact in the future. In vivo bone and cartilage engineering via combining a novel composite, biphasic scaffold technology with a MSC has been shown a high potential in the knee defect regeneration in the animal models. However, the clinical application of tissue

  8. Development of a Tissue-Engineered Lymphatic Graft Using Nanocomposite Polymer for the Treatment of Secondary Lymphedema.

    PubMed

    Kanapathy, Muholan; Kalaskar, Deepak; Mosahebi, Afshin; Seifalian, Alexander M

    2016-03-01

    Damage of the lymphatic vessels, commonly due to surgical resection for cancer treatment, leads to secondary lymphedema. Tissue engineering approach offers a possible solution to reconstruct this damage with the use of lymphatic graft to re-establish the lymphatic flow, hence preventing lymphedema. The aim of this study is to develop a tissue-engineered lymphatic graft using nanocomposite polymer and human dermal lymphatic endothelial cells (HDLECs). A nanocomposite polymer, the polyhedral oligomeric silsequioxane-poly(carbonate-urea)urethane (POSS-PCU), which has enhanced mechanical, chemical, and physical characteristics, was used to develop the lymphatic graft. POSS-PCU has been used clinically for the world's first synthetic trachea, lacrimal duct, and is currently undergoing clinical trial for coronary artery bypass graft. Two designs and fabrication methods were used to manufacture the conduits. The fabrication method, the mechanical and physical properties, as well as the hydraulic conductivity were tested. This is followed by in vitro cell culture analysis to test the cytocompatibility of HDLEC with the polymer surface. Using the casted extrusion method, the nanocomposite lymphatic graft demonstrates desirable mechanical property and hydraulic conductivity to re-establish the lymphatic flow. The conduit has high tensile strength (casted: 74.86 ± 5.74 MPa vs. coagulated: 31.33 ± 3.71 MPa; P < 0.001), favorable kink resistance, and excellent suture retention property (casted vs. coagulated, P < 0.05). Cytocompatibility study showed that the POSS-PCU scaffold supports the attachment and growth of HDLECs. This study demonstrates the feasibility of developing a tissue-engineered lymphatic graft using the nanocomposite polymer. It displays excellent mechanical property and cytocompatibility to HDLECs, offering much promise for clinical applications and as a new treatment option for secondary lymphedema. PMID:26517009

  9. Effects of sterilization and storage on the properties of ALP-grafted biomaterials for prosthetic and bone tissue engineering applications.

    PubMed

    Ferraris, S; Pan, G; Cassinelli, C; Mazzucco, L; Vernè, E; Spriano, S

    2012-10-01

    Grafting of the biomaterial surfaces with biomolecules is nowadays a challenging research field for prosthetic and bone tissue engineering applications. On the other hand, very few research works investigate the effect of the sterilization processes on the properties of functionalized biomaterials. In this study, the effects of different sterilization techniques (e.g. gamma and electron beam irradiation, ethylene oxide) on the enzymatic activity of bioactive glasses and Ti6Al4V grafted with alkaline phosphatase (ALP) have been analyzed. Sterility maintenance and in vitro bioactivity of the sterilized surfaces have also been investigated. Finally the effect of packaging and storage conditions has been considered. PMID:22971978

  10. USPIO-labeled textile materials for non-invasive MR imaging of tissue-engineered vascular grafts.

    PubMed

    Mertens, Marianne E; Koch, Sabine; Schuster, Philipp; Wehner, Jakob; Wu, Zhuojun; Gremse, Felix; Schulz, Volkmar; Rongen, Lisanne; Wolf, Frederic; Frese, Julia; Gesché, Valentine N; van Zandvoort, Marc; Mela, Petra; Jockenhoevel, Stefan; Kiessling, Fabian; Lammers, Twan

    2015-01-01

    Non-invasive imaging might assist in the clinical translation of tissue-engineered vascular grafts (TEVG). It can e.g. be used to facilitate the implantation of TEVG, to longitudinally monitor their localization and function, and to provide non-invasive and quantitative feedback on their remodeling and resorption. We here incorporated ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles into polyvinylidene fluoride (PVDF)-based textile fibers, and used them to prepare imageable tissue-engineered vascular grafts (iTEVG). The USPIO-labeled scaffold materials were molded with a mixture of fibrin, fibroblasts and smooth muscle cells, and then endothelialized in a bioreactor under physiological flow conditions. The resulting grafts could be sensitively detected using T1-, T2- and T2*-weighted MRI, both during bioreactor cultivation and upon surgical implantation into sheep, in which they were used as an arteriovenous shunt between the carotid artery and the jugular vein. In vivo, the iTEVG were shown to be biocompatible and functional. Post-mortem ex vivo analyses provided evidence for efficient endothelialization and for endogenous neo-vascularization within the biohybrid vessel wall. These findings show that labeling polymer-based textile materials with MR contrast agents is straightforward and safe, and they indicate that such theranostic tissue engineering approaches might be highly useful for improving the production, performance, personalization and translation of biohybrid vascular grafts. PMID:25465443

  11. Microstructural Remodeling of Articular Cartilage Following Defect Repair by Osteochondral Autograft Transfer

    PubMed Central

    Raub, CB; Hsu, SC; Chan, EF; Shirazi, R; Chen, AC; Chnari, E; Semler, EJ; Sah, RL

    2013-01-01

    Objective To assess collagen network alterations occurring with flow and other abnormalities of articular cartilage at medial femoral condyle (MFC) sites repaired with osteochondral autograft (OATS) after 6 and 12 months, using quantitative polarized light microscopy (qPLM) and other histopathological methods Design The collagen network structure of articular cartilage of OATS-repaired defects and non-operated contralateral control sites were compared by qPLM analysis of parallelism index (PI), orientation angle (α) relative to the local tissue axes, and retardance (Γ) as a function of depth. qPLM parameter maps were also compared to ICRS and Modified O’Driscoll grades, and cell and matrix sub-scores, for sections stained with H&E and Safranin-O, and for Collagen-I and II Results Relative to non-operated normal cartilage, OATS-repaired regions exhibited structural deterioration, with low PI and more horizontal α, and unique structural alteration in adjacent host cartilage: more aligned superficial zone, and reoriented deep zone lateral to the graft, and matrix disorganization in cartilage overhanging the graft. Shifts in α and PI from normal site-specific values were correlated with histochemical abnormalities and co-localized with changes in cell organization/orientation, cloning, or loss, indicative of cartilage flow, remodeling, and deterioration, respectively Conclusions qPLM reveals a number of unique localized alterations of the collagen network in both adjacent host and implanted cartilage in OATS-repaired defects, associated with abnormal chondrocyte organization. These alterations are consistent with mechanobiological processes and the direction and magnitude of cartilage strain. PMID:23528954

  12. Unusual Appearance of an Osteochondral Lesion Accompanying Medial Meniscus Injury

    PubMed Central

    Mine, Takatomo; Ihara, Koichiro; Kawamura, Hiroyuki; Date, Ryo; Chagawa, Kazuki

    2014-01-01

    An osteochondral lesion in the knee joint is caused by a focal traumatic osteochondral defect, osteochondritis dissecans, an isolated degenerative lesion, or diffuse degenerative disease. An osteochondral lesion with a cleft-like appearance accompanying medial meniscus injury is rare without trauma. We report the case of a 13-year-old boy who complained of right knee pain and swelling, with radiographic findings of an osteochondral defect. Arthroscopic inspection showed an osteochondral lesion in the medial condyle of the femur and tibial plateau accompanying a partial medial meniscus discoid tear. Partial meniscectomy was performed, and a microfracture procedure was carried out on the osteochondral defect. The patient was asymptomatic at 2 years' follow-up. This technique is a relatively easy, completely arthroscopic procedure that spares the bone and cartilage and has yielded a good clinical outcome in a skeletally immature patient who had an osteochondral lesion with a cleft-like appearance. PMID:24749028

  13. Rational design of an improved tissue-engineered vascular graft: determining the optimal cell dose and incubation time

    PubMed Central

    Lee, Yong-Ung; Mahler, Nathan; Best, Cameron A; Tara, Shuhei; Sugiura, Tadahisa; Lee, Avione Y; Yi, Tai; Hibino, Narutoshi; Shinoka, Toshiharu; Breuer, Christopher

    2016-01-01

    Aim We investigated the effect of cell seeding dose and incubation time on tissue-engineered vascular graft (TEVG) patency. Materials & methods Various doses of bone marrow-derived mononuclear cells (BM-MNCs) were seeded onto TEVGs, incubated for 0 or 12 h, and implanted in C57BL/6 mice. Different doses of human BM-MNCs were seeded onto TEVGs and measured for cell attachment. Results The incubation time showed no significant effect on TEVG patency. However, TEVG patency was significantly increased in a dose-dependent manner. In the human graft, more bone marrow used for seeding resulted in increased cell attachment in a dose-dependent manner. Conclusion Increasing the BM-MNC dose and reducing incubation time is a viable strategy for improving the performance and utility of the graft. PMID:26925512

  14. Clinical evaluation of expanded mesh connective tissue graft in the treatment for multiple adjacent gingival recessions in the esthetic zone

    PubMed Central

    Shanmugam, M.; Shivakumar, B.; Meenapriya, B.; Anitha, V.; Ashwath, B.

    2015-01-01

    Background: Multiple approaches have been used to replace lost, damaged or diseased gingival tissues. The connective tissue graft (CTG) procedure is the golden standard method for root coverage. Although multiple sites often need grafting, the palatal mucosa supplies only a limited area of grafting material. To overcome this limitation, expanded mesh graft provides a method whereby a graft can be stretched to cover a large area. The aim of this study was to evaluate the effectiveness and the predictability of expanded mesh CTG (e-MCTG) in the treatment of adjacent multiple gingival recessions. Materials and Methods: Sixteen patients aged 20–50 years contributed to 55 sites, each site falling into at least three adjacent Miller's Class 1 or Class 2 gingival recession. The CTG obtained from the palatal mucosa was expanded to cover the recipient bed, which was 1.5 times larger than the graft. Clinical measurements were recorded at baseline and 3 months, 12 months postoperatively. Results: A mean coverage of 1.96 mm ± 0.66 mm and 2.22 mm ± 0.68 mm was obtained at the end of 3rd and 12th month, respectively. Twelve months after surgery a statistically significant increase in CAL (2.2 mm ± 0.68 mm, P < 0.001) and increasing WKT (1.75 ± 0.78, P < 0.001) were obtained. In 80% of the treated sites, 100% root coverage was achieved (mean 93.5%). Conclusions: The results of this study demonstrated that multiple adjacent recessions were treated by using e-MCTG technique can be applied and highly predictable root coverage can be achieved. PMID:26321829

  15. Targeted SPECT/CT Imaging of Matrix Metalloproteinase Activity in the Evaluation of Remodeling Tissue-Engineered Vascular Grafts Implanted in a Growing Lamb Model

    PubMed Central

    Stacy, Mitchel R.; Naito, Yuji; Maxfield, Mark W.; Kurobe, Hirotsugu; Tara, Shuhei; Chan, Chung; Rocco, Kevin A.; Shinoka, Toshiharu; Sinusas, Albert J.; Breuer, Christopher K.

    2014-01-01

    Objective(s) The clinical translation of tissue-engineered vascular grafts has been demonstrated in children. The remodeling of biodegradable, cell-seeded scaffolds to functional neovessels is partially attributed to matrix metalloproteinases. Noninvasive assessment of matrix metalloproteinase activity may indicate graft remodeling and elucidate the progression of neovessel formation. Therefore, matrix metalloproteinase activity was evaluated in grafts implanted in lambs using in vivo and ex vivo hybrid imaging. Graft growth and remodeling was quantified using in vivo X-ray computed tomography angiography. Methods Cell-seeded and unseeded scaffolds were implanted in lambs (n=5) as inferior vena cava interposition grafts. At 2 and 6 months post-implantation, in vivo angiography assessed graft morphology. In vivo and ex vivo single photon emission tomography/X-ray computed tomography imaging was performed with a radiolabeled compound targeting matrix metalloproteinase activity at 6 months. Neotissue was examined at 6 months using qualitative histologic and immunohistochemical staining and quantitative biochemical analysis. Results Seeded grafts demonstrated significant luminal and longitudinal growth from 2 to 6 months. In vivo imaging revealed subjectively higher matrix metalloproteinase activity in grafts vs. native tissue. Ex vivo imaging confirmed a quantitative increase in matrix metalloproteinase activity and demonstrated higher activity in unseeded vs. seeded grafts. Glycosaminoglycan content was increased in seeded grafts vs. unseeded grafts, without significant differences in collagen content. Conclusions Matrix metalloproteinase activity remains elevated in tissue-engineered grafts 6 months post-implantation and may indicate remodeling. Optimization of in vivo imaging to noninvasively evaluate matrix metalloproteinase activity may assist in serial assessment of vascular graft remodeling. PMID:24952823

  16. Monitoring changes in heart tissue temperature and evaluation of graft function after coronary artery bypass grafting surgery.

    PubMed

    Lekas, Raimundas; Jakuska, Povilas; Krisciukaitis, Algimantas; Veikutis, Vincentas; Dzemyda, Gintautas; Mickevicius, Tomas; Morkūnaite, Kristina; Vilke, Alina; Treigys, Povilas; Civinskiene, Genuvaite; Andriuskevicius, Jonas; Vanagas, Tomas; Skauminas, Kestutis; Bernatoniene, Jurga

    2009-01-01

    Thermography is a relatively new contact-free method used in experimental and clinical studies and in cardiovascular surgery to investigate the myocardium and coronary artery function. Objects of complex study included mongrel dogs and patients with coronary artery disease who underwent cardiac surgery. For active dynamic thermography, we used a thermovision camera "A20V" (FLIR Systems, USA). Our data indicate that both experimental and clinical study performed on beating hearts could be an important approach to interoperation inspection of autovenous graft function. An infrared camera also can be successfully used to determine the extent of ischemic damage to the myocardium, heart, and blood vessels during surgery as a significant prognostic tool for evaluating outcome after cardiac operation. PMID:19357452

  17. Porcine embryos produced after intracytoplasmic sperm injection using xenogeneic pig sperm from neonatal testis tissue grafted in mice.

    PubMed

    Honaramooz, Ali; Cui, Xiang-Shun; Kim, Nam-Hyung; Dobrinski, Ina

    2008-01-01

    Embryo development after homologous intracytoplasmic sperm injection (ICSI) with sperm from testis tissue xenografts from pigs or any other farm animal species has not been evaluated critically. Here, we report development of porcine embryos in vitro following ICSI with sperm retrieved from xenografted neonatal pig testis. Small pieces of testis tissue from newborn piglets were grafted under the back skin of castrated immunodeficient mice (n = 4) and the xenografts were collected 8 months after grafting. Spermatozoa were recovered by mincing of the grafted tissue. For comparison, testicular, epididymal and ejaculated spermatozoa were also collected from mature boars. Oocytes injected with xenogeneic spermatozoa were either fixed to determine fertilisation processes (n = 89 in five replicates) or allowed to develop in vitro (n = 143 in four replicates). Xenogeneic porcine spermatozoa were fertilisation competent (24% v. 58%, 68%, 62% or 0% for xenogeneic v. control testicular, epididymal and ejaculated spermatozoa or no spermatozoa, respectively) and embryos developed to the blastocyst stage (8% v. 22%, 27%, 25% or 0%, respectively). These results demonstrate that porcine spermatozoa derived from immature testis tissue xenografted into mice are fertilisation competent, albeit at a lower rate than testicular, epididymal or ejaculated spermatozoa from control boars, and support embryo development after ICSI. PMID:18842182

  18. Osteointegration of soft tissue grafts within the bone tunnels in anterior cruciate ligament reconstruction can be enhanced.

    PubMed

    Kuang, Guan-Ming; Yau, W P; Lu, William W; Chiu, K Y

    2010-08-01

    Anterior cruciate ligament reconstruction with a soft tissue autograft (hamstring autograft) has grown in popularity in the last 10 years. However, the issues of a relatively long healing time and an inferior histological healing result in terms of Sharpey-like fibers connection in soft tissue grafts are still unsolved. To obtain a promising outcome in the long run, prompt osteointegration of the tendon graft within the bone tunnel is essential. In recent decades, numerous methods have been reported to enhance osteointegration of soft tissue graft in the bone tunnel. In this article, we review the current literature in this research area, mainly focusing on strategies applied to the local bone tunnel environment. Biological strategies such as stem cell and gene transfer technology, as well as the local application of specific growth factors have been reported to yield exciting results. The use of biological bone substitute and physical stimulation also obtained promising results. Artificially engineered tissue has promise as a solution to the problem of donor site morbidity. Despite these encouraging results, the current available evidence is still experimental. Further clinical studies in terms of randomized control trial in the future should be conducted to extrapolate these basic science study findings into clinical practice. PMID:19779894

  19. Comparative clinical evaluation of laterally positioned pedicle graft and subepithelial connective tissue graft in the treatment of Miller's Class I and II gingival recession: A 6 months study

    PubMed Central

    Dulani, Kirti Satish; Bhavsar, Neeta Vijay; Trivedi, Sakshee Rahul; Trivedi, Rahul Anil

    2015-01-01

    Aim: The purpose of the study was to compare clinical outcomes of laterally positioned pedicle graft (LPPG) and subepithelial connective tissue graft (SCTG) for treatment of Miller's Class I and II gingival recession defects, at the end of 6 months. Materials and Methods: Sixty Miller's Class I or II gingival recession defects (≥3 mm) (n = 30 each) on the labial aspect of anterior teeth were treated by either of the above techniques. Clinical parameters including recession depth (RD), width of keratinized gingiva (WKG), percentage of root coverage (%RC), and complete RC were recorded at baseline and 6 months postoperatively. Data were recorded and statistical analysis was done for both intergroup and intragroup. Statistical Analysis Used: Paired t-test intragroup and Student's t-test intergroup. Results: In LPPG, RD decreased from 4.9 ± 0.99 mm to 1.1 ± 0.3 mm and WKG increased from 0.7 ± 0.87 to 4.5 ± 0.86 mm at 6 months, while in SCTG, RD decreased from 4.67 ± 1.12 mm to 0.46 ± 0.68 mm and WKG increased from 1.1 ± 0.99 to 5.33 ± 0.72 mm at 6 months postoperatively. The values of the soft tissue coverage remained stable for 6 months. Conclusions: Highly significant and effective soft tissue coverage was obtained by both techniques. LPPG resulted in effective soft tissue coverage for isolated deep narrow defects while SCTG in isolated and multiple, deep narrow and wide defects. PMID:26941517

  20. Development and function of pearl-sacs grown from regenerated mantle graft tissue in the black-lip pearl oyster, Pinctada margaritifera (Linnaeus, 1758).

    PubMed

    Kishore, Pranesh; Southgate, Paul C

    2015-08-01

    Current pearl grafting techniques were developed in the early 1900s and have changed little since. They involve the sacrifice of donor pearl oysters to provide graft tissue (saibo) that is implanted into host oysters. This study assessed the feasibility of using regenerated graft tissue for pearl production in the 'black-lip' pearl oyster, Pinctada margaritifera. Twelve days after grafting with regenerated graft tissue, there was complete encapsulation of the nucleus by the fully developed pearl-sac and the first layer of organic matrix had been secreted. Sixteen days after grafting, the pearl-sac was completely integrated with host tissue. The epithelial cells in the pearl-sac continued to secrete the organic matrix layer but there were no signs of nacre deposition at this stage. However, after three months of culture, nuclei in oysters grafted with regenerated mantle tissue were completely covered with nacre. The average nacre thickness on pearls produced from regenerated (0.547 ± 0.01 mm, n = 8) and normal (0.532 ± 0.01 mm, n = 8) mantle tissue did not differ significantly (p > 0.05). Nacre secretion rates, over the 80 day period subsequent to pearl-sac formation were 6.84 ± 0.1 μm day(-1) and 6.66 ± 0.1 μm day(-1) for oysters grafted with regenerated and normal mantle tissue, respectively. These means were not significantly different (p = 0.258). Our results clearly show that regenerated mantle tissue can function successfully as saibo for pearl production in P. margaritifera. This finding could provide significant benefits to pearl farmers and a basis for further development of current pearl grafting practices. PMID:25982400

  1. Surgical treatment of localized gingival recessions using coronally advanced flaps with or without subepithelial connective tissue graft

    PubMed Central

    Bellver-Fernández, Ricardo; Martínez-Rodriguez, Ana-María; Gioia-Palavecino, Claudio; Caffesse, Raul-Guillermo

    2016-01-01

    Background A coronally advanced flap with subepithelial connective tissue graft is the gold standard surgical treatment of gingival recessions, since it offers a higher probability of achieving complete root coverage compared with other techniques. However, optimum short- and middle-term clinical results have also been obtained with coronally advanced flaps alone. The aim of the present study was to evaluate the results obtained by the surgical treatment of localized gingival recessions using coronally advanced flaps with or without subepithelial connective tissue graft. Material and Methods The reduction of recession height was assessed, together with the gain in gingival attachment apical to the recession, and total reduction of recession, in a comparative study of two techniques. Twenty-two gingival recessions were operated upon: 13 in the control group (coronally advanced flap) and 9 in the test group (coronally advanced flap associated to subepithelial connective tissue graft). Results After 18 months, the mean reduction of recession height was 2.2 ± 0.8 mm in the control group and 2.3 ± 0.7 mm in the test group, with a mean gain in gingival attachment of 1.3 ± 0.9 mm and 2.3 ± 1.3 mm, respectively. In percentage terms, the mean reduction of recession height was 84.6 ± 19.6% in the control group and 81.7 ± 17.8% in the test group, with a mean gain in gingival attachment of 20.5 ± 37.4% and 184.4 ± 135.5%, respectively. Conclusions Significant reduction of gingival recession was achieved with both techniques, though the mean gain in gingival attachment (in mm and as a %) was greater in test group. Key words:Gingival recession, coronally advanced flap, subepthelial connective tissue graft. PMID:26595836

  2. The first Australian experience of heterotopic grafting of cryopreserved ovarian tissue: evidence of establishment of normal ovarian function.

    PubMed

    Stern, Catharyn J; Toledo, Manuela G; Hale, Lyndon G; Gook, Debra A; Edgar, David H

    2011-06-01

    Cryostorage of reproductive potential, in the form of ovarian cortex, for young women about to undergo cytotoxic therapies has been offered clinically for some time. However, the prospects of re-establishing reproductive function using this tissue remain unclear. We now report reproducible follicular development, oocyte retrieval and embryo development following heterotopic grafting of cryopreserved ovarian cortex which had been stored for over 10 years. PMID:21631450

  3. TGF-β receptor 1 inhibition prevents stenosis of tissue-engineered vascular grafts by reducing host mononuclear phagocyte activation.

    PubMed

    Lee, Yong-Ung; de Dios Ruiz-Rosado, Juan; Mahler, Nathan; Best, Cameron A; Tara, Shuhei; Yi, Tai; Shoji, Toshihiro; Sugiura, Tadahisa; Lee, Avione Y; Robledo-Avila, Frank; Hibino, Narutoshi; Pober, Jordan S; Shinoka, Toshiharu; Partida-Sanchez, Santiago; Breuer, Christopher K

    2016-07-01

    Stenosis is a critical problem in the long-term efficacy of tissue-engineered vascular grafts (TEVGs). We previously showed that host monocyte infiltration and activation within the graft drives stenosis and that TGF-β receptor 1 (TGF-βR1) inhibition can prevent it, but the latter effect was attributed primarily to inhibition of mesenchymal cell expansion. In this study, we assessed the effects of TGF-βR1 inhibition on the host monocytes. Biodegradable TEVGs were implanted as inferior vena cava interposition conduits in 2 groups of C57BL/6 mice (n = 25/group): unseeded grafts and unseeded grafts with TGF-βR1 inhibitor systemic treatment for the first 2 wk. The TGF-βR1 inhibitor treatment effectively improved TEVG patency at 6 mo compared to the untreated control group (91.7 vs. 48%, P < 0.001), which is associated with a reduction in classic activation of mononuclear phagocytes. Consistent with these findings, the addition of rTGF-β to LPS/IFN-γ-stimulated monocytes enhanced secretion of inflammatory cytokines TNF-α, IL-12, and IL-6; this effect was blocked by TGF-βR1 inhibition (P < 0.0001). These findings suggest that the TGF-β signaling pathway contributes to TEVG stenosis by inducing classic activation of host monocytes. Furthermore, blocking monocyte activation by TGF-βR1 inhibition provides a viable strategy for preventing TEVG stenosis while maintaining neotissue formation.-Lee, Y.-U., de Dios Ruiz-Rosado, J., Mahler, N., Best, C. A., Tara, S., Yi, T., Shoji, T., Sugiura, T., Lee, A. Y., Robledo-Avila, F., Hibino, N., Pober, J. S., Shinoka, T., Partida-Sanchez, S., Breuer, C. K. TGF-β receptor 1 inhibition prevents stenosis of tissue-engineered vascular grafts by reducing host mononuclear phagocyte activation. PMID:27059717

  4. Osteochondral Allografts in the Ankle Joint

    PubMed Central

    Vannini, Francesca; Buda, Roberto; Ruffilli, Alberto; Cavallo, Marco; Giannini, Sandro

    2013-01-01

    Purpose: The aim of this systematic review is to report about the clinical use of partial and total fresh osteochondral allograft in the ankle joint. The state of the art of allografts with regard to basic science, procurement and storage methods, immunogenicity, generally accepted indications and contraindications, and the rationale of the allografting procedure have been described. Methods: All studies published in PubMed from 2000 to January 2012 addressing fresh osteochondral allograft procedures in the ankle joint were identified, including those that fulfilled the following criteria: (a) level I-IV evidence addressing the areas of interest outlined above; (b) measures of functional, clinical, or imaging outcome; and (c) outcome related to ankle cartilage lesions or ankle arthritis treated by allografts. Results: The analysis showed a progressively increasing number of articles from 2000. The number of selected articles was 14; 9 of those focused on limited dimension allografts (plugs, partial) and 5 on bipolar fresh osteochondral allografts. The evaluation of evidence level showed 14 case series and no randomized studies. Conclusions: Fresh osteochondral allografts are now a versatile and suitable option for the treatment of different degrees of osteochondral disease in the ankle joint and may even be used as total joint replacement. Fresh osteochondral allografts used for total joint replacement are still experimental and might be considered as a salvage procedure in otherwise unsolvable situations. A proper selection of the patients is therefore a key point. Moreover, the patients should be adequately informed about the possible risks, benefits, and alternatives to the allograft procedure. PMID:26069666

  5. In vitro characterization of design and compressive properties of 3D-biofabricated/decellularized hybrid grafts for tracheal tissue engineering.

    PubMed

    Johnson, Christopher; Sheshadri, Priyanka; Ketchum, Jessica M; Narayanan, Lokesh K; Weinberger, Paul M; Shirwaiker, Rohan A

    2016-06-01

    Infection or damage to the trachea, a thin walled and cartilage reinforced conduit that connects the pharynx and larynx to the lungs, leads to serious respiratory medical conditions which can often prove fatal. Current clinical strategies for complex tracheal reconstruction are of limited availability and efficacy, but tissue engineering and regenerative medicine approaches may provide viable alternatives. In this study, we have developed a new "hybrid graft" approach that utilizes decellularized tracheal tissue along with a resorbable polymer scaffold, and holds promise for potential clinical applications. First, we evaluated the effect of our decellularization process on the compression properties of porcine tracheal segments, and noted approximately 63% decrease in resistance to compression following decellularization. Next we developed four C-shape scaffold designs by varying the base geometry and thickness, and fabricated polycaprolactone scaffolds using a combination of 3D-Bioplotting and thermally-assisted forming. All scaffolds designs were evaluated in vitro under three different environmental testing conditions to determine the design that offered the best resistance to compression. These were further studied to determine the effect of gamma radiation sterilization and cyclic compression loading. Finally, hybrid grafts were developed by securing these optimal design scaffolds to decellularized tracheal segments and evaluated in vitro under physiological testing conditions. Results show that the resistance to compression offered by the hybrid grafts created using gamma radiation sterilized scaffolds was comparable to that of fresh tracheal segments. Given that current clinical attempts at tracheal transplantation using decellularized tissue have been fraught with luminal collapse and complications, our data support the possibility that future embodiments using a hybrid graft approach may reduce the need for intraluminal stenting in tracheal transplant

  6. Biomechanical Comparison of an Intramedullary and Extramedullary Free-Tissue Graft Reconstruction of the Acromioclavicular Joint Complex

    PubMed Central

    Garg, Rishi; Javidan, Pooya; Lee, Thay Q.

    2013-01-01

    Background Several different surgical techniques have been described to address the coracoclavicular (CC) ligaments in acromioclavicular (AC) joint injuries. However, very few techniques focus on reconstructing the AC ligaments, despite its importance in providing stability. The purpose of our study was to compare the biomechanical properties of two free-tissue graft techniques that reconstruct both the AC and CC ligaments in cadaveric shoulders, one with an extramedullary AC reconstruction and the other with an intramedullary AC reconstruction. We hypothesized intramedullary AC reconstruction will provide greater anteroposterior translational stability and improved load to failure characteristics than an extramedullary technique. Methods Six matched cadaveric shoulders underwent translational testing at 10 N and 15 N in the anteroposterior and superoinferior directions, under AC joint compression loads of 10 N, 20 N, and 30 N. After the AC and CC ligaments were transected, one of the specimens was randomly assigned the intramedullary free-tissue graft reconstruction while its matched pair received the extramedullary graft reconstruction. Both reconstructed specimens then underwent repeat translational testing, followed by load to failure testing, via superior clavicle distraction, at a rate of 50 mm/min. Results Intramedullary reconstruction provided significantly greater translational stability in the anteroposterior direction than the extramedullary technique for four of six loading conditions (p < 0.05). There were no significant differences in translational stability in the superoinferior direction for any loading condition. The intramedullary reconstructed specimens demonstrated improved load to failure characteristics with the intramedullary reconstruction having a lower deformation at yield and a higher ultimate load than the extramedullary reconstruction (p < 0.05). Conclusions Intramedullary reconstruction of the AC joint provides greater stability in the

  7. A Bi-Layered Elastomeric Scaffold for Tissue Engineering of Small-Diameter Vascular Grafts

    PubMed Central

    Soletti, Lorenzo; Hong, Yi; Guan, Jianjun; Stankus, John J.; El-Kurdi, Mohammed S.; Wagner, William R.; Vorp, David A.

    2011-01-01

    A major barrier in the development of a clinically-useful small-diameter tissue engineered vascular graft (TEVG) is the scaffold component. Scaffold requirements include matching the mechanical and structural properties with those of native vessels and optimizing the microenvironment to foster cell integration, adhesion, and growth. We have developed a small-diameter, bi-layered, biodegradable, elastomeric scaffold based on a synthetic, biodegradable elastomer. The scaffold incorporates a highly porous inner layer, allowing cell integration and growth, and an external, fibrous reinforcing layer deposited by electrospinning. Scaffold morphology and mechanical properties were assessed, quantified, and compared to those of native vessels. Scaffolds were then seeded with adult stem cells via a rotational vacuum seeding device to obtain a TEVG, cultured in dynamic conditions for 7 days, and evaluated for cellularity. The scaffold showed a firm integration of the two polymeric layers with no delaminations. Mechanical properties were physiologically-consistent showing anisotropy, elastic modulus (1.4±0.4 MPa), and ultimate tensile stress (8.3±1.7 MPa) comparable with native vessels. Compliance and suture retention force were 4.6±0.5×10−4 mmHg−1 and 3.4±0.3 N, respectively. Seeding resulted in a rapid, uniform, bulk integration of cells, with a seeding efficiency of 92±1%. The scaffolds maintained a high level of cellular density throughout dynamic culture. This approach, combining artery-like mechanical properties and a rapid and efficient cellularization, might contribute to the future clinical translation of TEVGs. PMID:19540370

  8. Hip Arthroscopic Osteochondral Autologous Transplantation for Treating Osteochondritis Dissecans of the Femoral Head

    PubMed Central

    Kubo, Takanori; Utsunomiya, Hajime; Watanuki, Makoto; Hayashi, Hidetoshi; Sakai, Akinori; Uchida, Soshi

    2015-01-01

    Osteochondritis dissecans (OCD) of the femoral head is not a common source of hip pain. Hip arthroscopy is becoming a more frequent indication for intra-articular pathologies of the hip. Osteochondral autologous transplantation is a promising technique that theoretically can reconstruct osteochondral lesions of the femoral head. We describe our technique for arthroscopic antegrade osteochondral autologous transplantation for the treatment of OCD of the femoral head. The advantages of this technique include that it is a less invasive method with the ability to assess and treat intra-articular pathologies associated with OCD of the femoral head at same time. Case series and outcomes after this technique are not currently reported in the literature; however, it could be a less invasive method and provide favorable clinical outcomes for patients with OCD lesions of the femoral head. PMID:26870645

  9. Free bone graft reconstruction of irradiated facial tissue: Experimental effects of basic fibroblast growth factor stimulation

    SciTech Connect

    Eppley, B.L.; Connolly, D.T.; Winkelmann, T.; Sadove, A.M.; Heuvelman, D.; Feder, J. )

    1991-07-01

    A study was undertaken to evaluate the potential utility of basic fibroblast growth factor in the induction of angiogenesis and osseous healing in bone previously exposed to high doses of irradiation. Thirty New Zealand rabbits were evaluated by introducing basic fibroblast growth factor into irradiated mandibular resection sites either prior to or simultaneous with reconstruction by corticocancellous autografts harvested from the ilium. The fate of the free bone grafts was then evaluated at 90 days postoperatively by microangiographic, histologic, and fluorochrome bone-labeling techniques. Sequestration, necrosis, and failure to heal to recipient osseous margins was observed both clinically and histologically in all nontreated irradiated graft sites as well as those receiving simultaneous angiogenic stimulation at the time of graft placement. No fluorescent activity was seen in these graft groups. In the recipient sites pretreated with basic fibroblast growth factor prior to placement of the graft, healing and reestablishment of mandibular contour occurred in nearly 50 percent of the animals. Active bone formation was evident at cortical margins adjacent to the recipient sites but was absent in the more central cancellous regions of the grafts.

  10. Comparison of a Closed System to a Standard Open Technique for Preparing Tissue-Engineered Vascular Grafts

    PubMed Central

    Kurobe, Hirotsugu; Maxfield, Mark W.; Naito, Yuji; Cleary, Muriel; Stacy, Mitchel R.; Solomon, Daniel; Rocco, Kevin A.; Tara, Shuhei; Lee, Avione Y.; Sinusas, Albert J.; Snyder, Edward L.; Shinoka, Toshiharu

    2015-01-01

    We developed a prototype for a closed apparatus for assembling tissue-engineered vascular grafts (TEVGs) with the goal of creating a simple operator-independent method for making TEVGs to optimize safety and enable widespread application of this technology. The TEVG is made by seeding autologous bone marrow-derived mononuclear cells onto a biodegradable tubular scaffold and is the first man-made vascular graft to be successfully used in humans. A critical barrier, which has prevented the widespread clinical adoption of the TEVG, is that cell isolation, scaffold seeding, and incubation are performed using an open method. To reduce the risk of contamination, the TEVG is assembled in a clean room. Clean rooms are expensive to build, complex to operate, and are not available in most hospitals. In this investigation, we used an ovine model to compare the safety and efficacy of TEVGs created using either a standard density centrifugation-based open method or the new filter-based closed system. We demonstrated no graft-related complications and maintenance of growth capacity in TEVGs created using the closed apparatus. In addition, the use of the closed system reduced the amount of time needed to assemble the TEVG by ∼50%. Adaptation of similar methodologies may facilitate the safe translation and the widespread use of other tissue engineering technologies. PMID:24866863

  11. Repair Mechanism of Osteochondral Defect Promoted by Bioengineered Chondrocyte Sheet

    PubMed Central

    Kamei, Naosuke; Adachi, Nobuo; Hamanishi, Michio; Kamei, Goki; Mahmoud, Elhussein Elbadry; Nakano, Tomohiro; Iwata, Takanori; Yamato, Masayuki; Okano, Teruo; Ochi, Mitsuo

    2015-01-01

    Cell sheet engineering has developed as a remarkable method for cell transplantation. In the field of cartilage regeneration, several studies previously reported that cartilage defects could be regenerated by transplantation of a chondrocyte sheet using cell sheet engineering. However, it remains unclear how such a thin cell sheet could repair a deep cartilage defect. We, therefore, focused on the mechanism of cartilage repair using cell sheet engineering in this study. Chondrocyte sheets and synovial cell sheets were fabricated using cell sheet engineering, and these allogenic cell sheets were transplanted to cover an osteochondral defect in a rat model. Macroscopic and histological evaluation was performed at 4 and 12 weeks after transplantation. Analysis of the gene expression of each cell sheet and of the regenerated tissue at 1 week after transplantation was performed. In addition, green fluorescent protein (GFP) transgenic rats were used as donors (transplanted chondrocyte sheets) or recipients (osteochondral defect models) to identify the cell origin of regenerated cartilage. Cartilage repair was significantly better in the group implanted with a chondrocyte sheet than in that with a synovial cell sheet. The results of gene expression analysis suggest that the possible factor contributing to cartilage repair might be TGFβ1. Cell tracking experiments using GFP transgenic rats showed that the regenerated cartilage was largely composed of cells derived from the transplanted chondrocyte sheets. PMID:25396711

  12. Bioactive and metal uptake studies of carboxymethyl chitosan-graft-D-glucuronic acid membranes for tissue engineering and environmental applications.

    PubMed

    Jayakumar, R; Rajkumar, M; Freitas, H; Sudheesh Kumar, P T; Nair, S V; Furuike, T; Tamura, H

    2009-08-01

    Carboxymethyl chitosan-graft-D-glucuronic acid (CMCS-g-D-GA) was prepared by grafting D-GA onto CMCS in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and then the membranes were made from it. In this work, the bioactivity studies of CMCS-g-D-GA membranes were carried out and then characterized by SEM, CLSM, XRD and FT-IR. The CMCS-g-D-GA membranes were found to be bioactive. The adsorption of Ni2+, Zn2+ and Cu2+ ions onto CMCS-g-D-GA membranes has also been investigated. The maximum adsorption capacity of CMCS-g-D-GA for Ni2+, Zn2+ and Cu2+ was found to be 57, 56.4 and 70.2 mg/g, respectively. Hence, these membranes were useful for tissue engineering, environmental and water purification applications. PMID:19409415

  13. Development of a Surgically Optimized Graft Insertion Suture Technique to Accommodate a Tissue-Engineered Tendon In Vivo

    PubMed Central

    Sawadkar, Prasad; Alexander, Susan; Tolk, Marten; Wong, Jason; McGrouther, Duncan; Bozec, Laurent

    2013-01-01

    Abstract The traumatic rupture of tendons is a common clinical problem. Tendon repair is surgically challenging because the tendon often retracts, resulting in a gap between the torn end and its bony insertion. Tendon grafts are currently used to fill this deficit but are associated with potential complications relating to donor site morbidity and graft necrosis. We have developed a highly reproducible, rapid process technique to manufacture compressed cell-seeded type I collagen constructs to replace tendon grafts. However, the material properties of the engineered constructs are currently unsuitable to withstand complete load bearing in vivo. A modified suture technique has been developed to withstand physiological loading and off load the artificial construct while integration occurs. Lapine tendons were used ex vivo to test the strength of different suture techniques with different sizes of Prolene sutures and tissue-engineered collagen constructs in situ. The data were compared to standard modified Kessler suture using a standard tendon graft. Mechanical testing was carried out and a finite element analysis stress distribution model constructed using COMSOL 3.5 software. The break point for modified suture technique with a tissue-engineered scaffold was significantly higher (50.62 N) compared to a standard modified Kessler suture (12.49 N, p<0.05). Distributing suture tension further proximally and distally from the tendon ends increased the mechanical strength of the repairs. We now have ex vivo proof of concept that this suture technique is suitable for testing in vivo, and this will be the next stage of our research. PMID:24083088

  14. Kinetic study of the replacement of porcine small intestinal submucosa grafts and the regeneration of meniscal-like tissue in large avascular meniscal defects in dogs.

    PubMed

    Cook, J L; Tomlinson, J L; Arnoczky, S P; Fox, D B; Reeves Cook, C; Kreeger, J M

    2001-06-01

    Porcine small intestinal submucosa (SIS) was used to replace large, avascular defects in the medial menisci of dogs. Twelve dogs received SIS grafts and 3 dogs were left untreated as controls. Dogs were evaluated at 4, 8, and 12 weeks by means of lameness scoring and ultrasonography. Dogs were sacrificed at 1, 6, or 12 weeks after implantation, and the tissue at the site of meniscal resection was evaluated for gross and histologic appearance, cross-sectional and surface area, and collagen types I and II. The femoral and tibial condyles were assessed for articular cartilage damage. Control dogs were significantly more lame than grafted dogs 8 and 12 weeks after instrumentation. Grafted dogs' replacement tissue appeared meniscal-like when evaluated grossly and ultrasonographically 12 weeks after instrumentation. The amount of replacement tissue was significantly greater in both cross-sectional and surface area for grafted dogs than for controls at all time points. Histologically, the SIS biomaterial could be identified in all grafted dogs at 1 week post-implantation, but in none at 6 weeks post-implantation. Subjectively, grafted dogs' replacement tissue was histologically superior to that of controls with respect to tissue type, organization, and architecture. Collagen types I and II immunoreactivity in grafted menisci were similar to that of normal menisci. Control dogs had significantly more articular cartilage damage than grafted dogs. SIS appears to induce regeneration of meniscal-like tissue in large, avascular meniscal defects in dogs, resulting in superior clinical function and articular cartilage protection compared to ungrafted controls. PMID:11429152

  15. Evaluation of a press-fit osteochondral poly(ester-urethane) scaffold in a rabbit defect model.

    PubMed

    Dresing, Iska; Zeiter, Stephan; Auer, Jörg; Alini, Mauro; Eglin, David

    2014-07-01

    The purpose of this study was to evaluate the impact on osteochondral healing of press-fitted multiphasic osteochondral scaffolds consisting of poly(ester-urethane) (PUR) and hydroxyapatite into a cylindric osteochondral defect in the distal non-weight bearing femoral trochlear ridge of the rabbit. Two scaffolds were investigated, one with and one without an intermediate microporous membrane between the cartilage and the bone compartment of the scaffold. A control group without a scaffold placed into the defect was included. After 12 weeks macroscopic and histomorphological analyses were performed. The scaffold was easily press-fitted and provided a stable matrix for tissue repair. The membrane did not demonstrate a detrimental effect on tissue healing compared with the scaffold without membrane. However, the control group had statistically superior healing as reflected by histological differences in the cartilage and subchondral bone compartment between control group and each scaffold group. A more detailed analysis revealed that the difference was localized in the bone compartment healing. The present study demonstrates that an elastomeric PUR scaffold can easily be press-fitted into an osteochondral defect and provides a stable matrix for tissue repair. However, the multi-phasic scaffold did not provide a clear advantage for tissue healing. Future investigations should refine especially the bone phase of the implant to increase its stiffness, biocompatibility and osteoconductive activity. A more precise fabrication technique would be necessary for the matching of tissue organisation. PMID:24668269

  16. The use of a biological graft for the closure of large abdominal wall defects following excision of soft tissue tumours

    PubMed Central

    Illingworth, Emma; Rooney, Paul S.; Heath, Richard; Chandrasekar, Coonoor R.

    2015-01-01

    Primary soft tissue tumours arising from the abdominal wall are uncommon and surgical excision of such tumours can result in large abdominal wall defects. There are many techniques available for abdominal wall repair following tumour excision, each having its own advantages and disadvantages. The options range from direct closure to the use of tissue flap reconstructions and/or prosthetic meshes. Currently, synthetic material such as polypropylene mesh is a common choice for closure of abdominal wall defects after tumour excision. Biological meshes are an alternative option for repair, and this report outlines two cases of abdominal wall repair using the porcine intestinal submucosa biological graft following excision of abdominal wall tumours. There was no evidence of infection, recurrence, seroma or hernias at 2-year follow-up. Following excision of soft tissue tumours of the abdominal wall, biological reconstructions can be successfully used to bridge the defect with minimal morbidity. PMID:26109681

  17. Experimental study on the construction of small three-dimensional tissue engineered grafts of electrospun poly-ε-caprolactone.

    PubMed

    Zhu, Guang-Chang; Gu, Yong-Quan; Geng, Xue; Feng, Zeng-Guo; Zhang, Shu-Wen; Ye, Lin; Wang, Zhong-Gao

    2015-02-01

    Studies on three-dimensional tissue engineered graft (3DTEG) have attracted great interest among researchers as they present a means to meet the pressing clinical demand for tissue engineering scaffolds. To explore the feasibility of 3DTEG, high porosity poly-ε-caprolactone (PCL) was obtained via the co-electrospinning of polyethylene glycol and PCL, and used to construct small-diameter poly-ε-caprolactone-lysine (PCL-LYS-H) scaffolds, whereby heparin was anchored to the scaffold surface by lysine groups. A variety of small-diameter 3DTEG models were constructed with different PCL layers and the mechanical properties of the resulting constructs were evaluated in order to select the best model for 3DTEGs. Bone marrow mononuclear cells were induced and differentiated to endothelial cells (ECs) and smooth muscle cells (SMCs). A 3DTEG (labeled '10-4%') was successfully produced by the dynamic co-culture of ECs on the PCL-LYS-H scaffolds and SMCs on PCL. The fluorescently labeled cells on the 3DTEG were subsequently observed by laser confocal microscopy, which showed that the ECs and SMCs were embedded in the 3DTEG. Nitric oxide and endothelial nitric oxide synthase assays showed that the ECs behaved normally in the 3DTEG. This study consequently provides a new thread to produce small-diameter tissue engineered grafts, with excellent mechanical properties, that are perfusable to vasculature and functional cells. PMID:25665848

  18. A functional chitosan membrane with grafted epigallocatechin-3-gallate and lovastatin enhances periodontal tissue regeneration in dogs.

    PubMed

    Lee, Bor-Shiunn; Lee, Chien-Chen; Lin, Hung-Pin; Shih, Wei-An; Hsieh, Wan-Ling; Lai, Chern-Hsiung; Takeuchi, Yasuo; Chen, Yi-Wen

    2016-10-20

    Currently used guided tissue regeneration (GTR) membranes are mainly used as a barrier to prevent epithelial cells growth into defects before new bone formation. The aim of this study was to develop a tri-layer functional chitosan (CS) membrane with epigallocatechin-3-gallate (EGCG) grafted on the outer layer for bactericidal activity, and lovastatin was included in the middle layer for controlled release. Successful EGCG grafting was demonstrated using Fourier transform infrared spectroscopy and EGCG grafting significantly enhanced adhesion and proliferation of human gingival fibroblasts. The release duration of lovastatin reached 21days. CS-Lovastatin1 produced the highest alkaline phosphatase activity and EGCG14-CS exhibited the best bactericidal activity against periodontopathic bacteria. Finally, the EGCG14-CS-Lovastatin1 membrane showed a higher percentage of bone regeneration than BioMend(®) and control groups in one-walled defects of beagle dogs. These results suggest that the EGCG14-CS-Lovastatin1 membrane has the potential to be used as a novel GTR membrane. PMID:27474626

  19. [Animal experiments on cementing small osteochondral fragments with fibrin glue].

    PubMed

    Zilch, H

    1980-01-01

    An experiment on revascularization of glued osteochondral fragments was carried out. A chiseled part of the medial femoral condyle of the knee joint of the rabbit was fixed on the right side with an acryl adhesive and on the left side with a new fibrinogen adhesive system (FAS), consisting of highly concentrated fibrinogen, thrombin, and factor XIII. The animals were sacrificed after three, six, ten, and twenty eight days. The FAS is changed into granulation tissue rich in vessels and, therefore, there is a quick revascularization of the fragments soon after three days. On the contrary the acryl adhesive is a foreign body and prevents ingrowth of capillaries during the time of investigation. Immobilization with plaster is necessary to prevent the fragment from gliding off. PMID:6972890

  20. Insulin-like growth factor-I and slow, bi-directional perfusion enhance the formation of tissue-engineered cardiac grafts.

    PubMed

    Cheng, Mingyu; Moretti, Matteo; Engelmayr, George C; Freed, Lisa E

    2009-03-01

    Biochemical and mechanical signals enabling cardiac regeneration can be elucidated using in vitro tissue-engineering models. We hypothesized that insulin-like growth factor-I (IGF) and slow, bi-directional perfusion could act independently and interactively to enhance the survival, differentiation, and contractile performance of tissue-engineered cardiac grafts. Heart cells were cultured on three-dimensional porous scaffolds in medium with or without supplemental IGF and in the presence or absence of slow, bi-directional perfusion that enhanced transport and provided shear stress. Structural, molecular, and electrophysiologic properties of the resulting grafts were quantified on culture day 8. IGF had independent, beneficial effects on apoptosis (p < 0.01), cellular viability (p < 0.01), contractile amplitude (p < 0.01), and excitation threshold (p < 0.01). Perfusion independently affected the four aforementioned parameters and also increased amounts of cardiac troponin-I (p < 0.01), connexin-43 (p < 0.05), and total protein (p < 0.01) in the grafts. Interactive effects of IGF and perfusion on apoptosis were also present (p < 0.01). Myofibrillogenesis and spontaneous contractility were present only in grafts cultured with perfusion, although contractility was inducible by electrical field stimulation of grafts from all groups. Our findings demonstrate that multi-factorial stimulation of tissue-engineered cardiac grafts using IGF and perfusion resulted in independent and interactive effects on heart cell survival, differentiation, and contractility. PMID:18759675

  1. Role of oxygen as a regulator of stem cell fate during the spontaneous repair of osteochondral defects.

    PubMed

    O'Reilly, Adam; Kelly, Daniel J

    2016-06-01

    The complexity of the in vivo environment makes it is difficult to isolate the effects of specific cues on regulating cell fate during regenerative events such as osteochondral defect repair. The objective of this study was to develop a computational model to explore how joint specific environmental factors regulate mesenchymal stem cell (MSC) fate during osteochondral defect repair. To this end, the spontaneous repair process within an osteochondral defect was simulated using a tissue differentiation algorithm which assumed that MSC fate was regulated by local oxygen levels and substrate stiffness. The developed model was able to predict the main stages of tissue formation observed by a number of in vivo studies. Following this, a parametric study was conducted to better understand why interventions that modulate angiogenesis dramatically impact the outcome of osteochondral defect healing. In the simulations where angiogenesis was reduced, by week 12, the subchondral plate was predicted to remain below the native tidemark, although the chondral region was composed entirely of cartilage and fibrous tissue. In the simulations where angiogenesis was increased, more robust cell proliferation and cartilage formation were observed during the first 4 weeks, however, by week 12 the subchondral plate had advanced above the native tidemark although any remaining tissue was either hypertrophic cartilage or fibrous tissue. These results suggest that osteochondral defect repair could be enhanced by interventions where angiogenesis is promoted but confined to within the subchondral region of the defect. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1026-1036, 2016. PMID:26595173

  2. Silk-Based Electrospun Tubular Scaffolds for Tissue-Engineered Vascular Grafts

    PubMed Central

    Soffer, Leah; Wang, Xianyan; Zhang, Xiaohui; Kluge, Jonathan; Dorfmann, Luis; Kaplan, David L.; Leisk, Gary

    2009-01-01

    Electrospinning was used to fabricate nonwoven nanofibrous tubular structures from Bombyx mori silk fibroin using an all aqueous process. The tubes were prepared for cell studies related to the bioengineering of small diameter vascular grafts. Prior to cell culture, the structures displayed a burst strength of 811±77.2 mmHg, sufficient to withstand arterial pressures. The tensile properties were similar to native vessels, with an ultimate tensile strength of 2.42± 0.48 MPa and a linear modulus of 2.45±0.47 MPa. Human endothelial cells and smooth muscle cells were successfully cultured on the electrospun silk, demonstrating the potential utility of these scaffolds for vascular grafts due to the combination of impressive mechanical properties and biological compatibility. PMID:18419943

  3. Photodynamic damage to cartilage and synovial tissue grafted on a chick's chorioallantoic membrane

    NASA Astrophysics Data System (ADS)

    Fisher, M.; Nahir, A. M.; Kimel, Sol

    1997-09-01

    Rheumatoid arthritis (RA) is a chronic inflammatory disease of the synovial joints causing pain deformities and disability. The highly vascular inflamed synovium has aggressive and destructive characteristics, it invades, erodes and gradually destroys cartilage and underlying bone. Photodynamic therapy (PDT) was performed using the chick chorioallantoic membrane (CAM) model to investigate the vitality of synovium and cartilage implanted on the CAM. Synovium, obtained from human patients, was grafted onto the CAM; gross microscopy and histology proved its vitality 7 days post grafting. Cartilage obtained from rabbit knee joint was also maintained on the CAM for 7 days. Its vitality was demonstrated by histology and by measuring metabolic and enzymatic activity of cartilage cells (chondrocytes) as well as the collagen and proteoglycans content. Selective PDT was performed using aluminum phthalocyanine tetrasulfonate (AlPcS4), a hydrophilic compound, soluble in biological solutions, as a photosensitizer. After irradiation with a diode laser (lambda equals 670 nm, 10 mW) damage was observed in vascularized synovium grafts, whereas avascular cartilage remained intact.

  4. Real-time immune cell interactions in target tissue during autoimmune-induced damage and graft tolerance

    PubMed Central

    Miska, Jason; Abdulreda, Midhat H.; Devarajan, Priyadharshini; Lui, Jen Bon; Suzuki, Jun; Pileggi, Antonello; Berggren, Per-Olof

    2014-01-01

    Real-time imaging studies are reshaping immunological paradigms, but a visual framework is lacking for self-antigen-specific T cells at the effector phase in target tissues. To address this issue, we conducted intravital, longitudinal imaging analyses of cellular behavior in nonlymphoid target tissues to illustrate some key aspects of T cell biology. We used mouse models of T cell–mediated damage and protection of pancreatic islet grafts. Both CD4+ and CD8+ effector T (Teff) lymphocytes directly engaged target cells. Strikingly, juxtaposed β cells lacking specific antigens were not subject to bystander destruction but grew substantially in days, likely by replication. In target tissue, Foxp3+ regulatory T (Treg) cells persistently contacted Teff cells with or without involvement of CD11c+ dendritic cells, an observation conciliating with the in vitro “trademark” of Treg function, contact-dependent suppression. This study illustrates tolerance induction by contact-based immune cell interaction in target tissues and highlights potentials of tissue regeneration under antigenic incognito in inflammatory settings. PMID:24567447

  5. Osteochondral defects in the ankle: why painful?

    PubMed Central

    Reilingh, Mikel L.; Zengerink, Maartje; van Bergen, Christiaan J. A.

    2010-01-01

    Osteochondral defects of the ankle can either heal and remain asymptomatic or progress to deep ankle pain on weight bearing and formation of subchondral bone cysts. The development of a symptomatic OD depends on various factors, including the damage and insufficient repair of the subchondral bone plate. The ankle joint has a high congruency. During loading, compressed cartilage forces its water into the microfractured subchondral bone, leading to a localized high increased flow and pressure of fluid in the subchondral bone. This will result in local osteolysis and can explain the slow development of a subchondral cyst. The pain does not arise from the cartilage lesion, but is most probably caused by repetitive high fluid pressure during walking, which results in stimulation of the highly innervated subchondral bone underneath the cartilage defect. Understanding the natural history of osteochondral defects could lead to the development of strategies for preventing progressive joint damage. PMID:20151110

  6. Osteochondritis Dessicans- Primary Fixation using Bioabsorbable Implants

    PubMed Central

    Galagali, Anand; Rao, Muralidhar

    2012-01-01

    Introduction: Osteochondritis dessicans (OCD) is a localized condition where a section of articular cartilage and underlying subchondral bone separate from the joint surface. It is important to diagnose unstable OCD early and fix the fragments primarily as the results of any surgical management at late presentations are guarded. Use of bioabsorbable implants for fixing OCD is recent and we report one such case in grade IV OCD. Case Report: We present a 14 year old girl who came with a history of acute pain, swelling, inability to bear weight on the right knee following a dance practice. MRI showed stage IV osteochondral fragment measuring 20x 8mm lying free. This was primarily fixed with bioabsorbable implants. 10 months follow up showed excellent clinical and functional results. Conclusion: This case highlights the advantages of early primary fixation whenever possible. By far, to our knowledge, this is the first case of successful treatment of stage IV OCD using bioabsorbable implants.

  7. Microsphere-based gradient implants for osteochondral regeneration: a long-term study in sheep

    PubMed Central

    Mohan, Neethu; Gupta, Vineet; Sridharan, Banu Priya; Mellott, Adam J; Easley, Jeremiah T; Palmer, Ross H; Galbraith, Richard A; Key, Vincent H; Berkland, Cory J; Detamore, Michael S

    2015-01-01

    Background: The microfracture technique for cartilage repair has limited ability to regenerate hyaline cartilage. Aim: The current study made a direct comparison between microfracture and an osteochondral approach with microsphere-based gradient plugs. Materials & methods: The PLGA-based scaffolds had opposing gradients of chondroitin sulfate and β-tricalcium phosphate. A 1-year repair study in sheep was conducted. Results: The repair tissues in the microfracture were mostly fibrous and had scattered fissures with degenerative changes. Cartilage regenerated with the gradient plugs had equal or superior mechanical properties; had lacunated cells and stable matrix as in hyaline cartilage. Conclusion: This first report of gradient scaffolds in a long-term, large animal, osteochondral defect demonstrated potential for equal or better cartilage repair than microfracture. PMID:26418471

  8. Immediate placement and provisionalization of maxillary anterior single implant with guided bone regeneration, connective tissue graft, and coronally positioned flap procedures.

    PubMed

    Waki, Tomonori; Kan, Joseph Y K

    2016-01-01

    Immediate implant placement and provisionalization in the esthetic zone have been documented with success. The benefit of immediate implant placement and provisionalization is the preservation of papillary mucosa. However, in cases with osseous defects presenting on the facial bony plate, immediate implant placement procedures have resulted in facial gingival recession. Subepithelial connective tissue grafts for immediate implant placement and provisionalization procedures have been reported with a good esthetic outcome. Biotype conversion around implants with subepithelial connective tissue grafts have been advocated, and the resulting tissues appear to be more resistant to recession. The dimensions of peri-implant mucosa in a thick biotype were significantly greater than in a thin biotype. Connective tissue graft with coronally positioned flap procedures on natural teeth has also been documented with success. This article describes a technique combining immediate implant placement, provisionalization, guided bone regeneration (GBR), connective tissue graft, and a coronally positioned flap in order to achieve more stable peri-implant tissue in facial osseous defect situations. PMID:27092345

  9. 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

  10. Evaluation of oriented electrospun fibers for periosteal flap regeneration in biomimetic triphasic osteochondral implant.

    PubMed

    Liu, Xudong; Liu, Shen; Liu, Shenghe; Cui, Wenguo

    2014-10-01

    Osteochondral defects represent a serious clinical problem. Although the cell-scaffold complexes have been reported to be effective for repairing osteochondral defects, a periosteal flap is frequently needed to arrest leakage of the implanted cells into the defect and to contribute to the secretion of cytokines to stimulate cartilage repair. The electrospun mesh mimicking the function of the flap assists tissue regeneration by preventing cell leakage and merits favorable outcomes in the cartilaginous region. In this study, an oriented poly(ε-caprolactone) (PCL) fibrous membrane (OEM) was fabricated by electrospinning as a periosteal scaffold and then freeze-dried with a collagen type I and hyaluronic acid cartilage scaffold (CH) and finally, freeze-dried with a tricalcium phosphate (TCP) bone substratum. Scanning electron microscopic images show obvious microstructure formation of the trilayered scaffolds, and electrospun fibrous membranes have an oriented fibrous network structure for the periosteal phase. Also shown are opened and interconnected pores with well designed three-dimensional structure, able to be bound in the CH (chondral phase) and TCP (osseous phase) scaffolds. In vitro results showed that the OEM can promote the orientation of bone marrow mesenchymal stem cell (BMSCs) and BMSCs can penetrate into the CH and TCP. After successfully combining the BMSCs, the tissue-engineered cartilage which contained the OEM and TCP complex was successfully used to regenerate the osteochondral defects in the rabbit model with greatly improved repair effects. PMID:24644257

  11. Tuning Cell Differentiation into a 3D Scaffold Presenting a Pore Shape Gradient for Osteochondral Regeneration.

    PubMed

    Di Luca, Andrea; Lorenzo-Moldero, Ivan; Mota, Carlos; Lepedda, Antonio; Auhl, Dietmar; Van Blitterswijk, Clemens; Moroni, Lorenzo

    2016-07-01

    Osteochondral regeneration remains nowadays a major problem since the outcome of current techniques is not satisfactory in terms of functional tissue formation and development. A possible solution is the combination of human mesenchymal stem cells (hMSCs) with additive manufacturing technologies to fabricate scaffolds with instructive properties. In this study, the differentiation of hMSCs within a scaffold presenting a gradient in pore shape is presented. The variation in pore shape is determined by varying the angle formed by the fibers of two consequent layers. The fiber deposition patterns are 0-90, which generate squared pores, 0-45, 0-30, and 0-15, that generate rhomboidal pores with an increasing major axis as the deposition angle decreases. Within the gradient construct, squared pores support a better chondrogenic differentiation whereas cells residing in the rhomboidal pores display a better osteogenic differentiation. When cultured under osteochondral conditions the trend in both osteogenic and chondrogenic markers is maintained. Engineering the pore shape, thus creating axial gradients in structural properties, seems to be an instructive strategy to fabricate functional 3D scaffolds that are able to influence hMSCs differentiation for osteochondral tissue regeneration. PMID:27109461

  12. Tissue Engineering of Ureteral Grafts: Preparation of Biocompatible Crosslinked Ureteral Scaffolds of Porcine Origin

    PubMed Central

    Koch, Holger; Hammer, Niels; Ossmann, Susann; Schierle, Katrin; Sack, Ulrich; Hofmann, Jörg; Wecks, Mike; Boldt, Andreas

    2015-01-01

    The surgical reconstruction of ureteric defects is often associated with post-operative complications and requires additional medical care. Decellularized ureters originating from porcine donors could represent an alternative therapy. Our aim was to investigate the possibility of manufacturing decellularized ureters, the characteristics of the extracellular matrix (ECM) and the biocompatibility of these grafts in vitro/in vivo after treatment with different crosslinking agents. To achieve these goals, native ureters were obtained from pigs and were decellularized. The success of decellularization and the ECM composition were characterized by (immuno)histological staining methods and a DNA-assay. In vitro: scaffolds were crosslinked either with carbodiimide (CDI), genipin (GP), glutaraldehyde, left chemically untreated or were lyophilized. Scaffolds in each group were reseeded with Caco2, LS48, 3T3 cells, or native rat smooth muscle cells (SMC). After 2 weeks, the number of ingrown cells was quantified. In vivo: crosslinked scaffolds were implanted subcutaneously into rats and the type of infiltrating cells were determined after 1, 9, and 30 days. After decellularization, scaffold morphology and composition of ECM were maintained, all cellular components were removed, DNA destroyed and strongly reduced. In vitro: GP and CDI scaffolds revealed a higher number of ingrown 3T3 and SMC cells as compared to untreated scaffolds. In vivo: at day 30, implants were predominantly infiltrated by fibroblasts and M2 anti-inflammatory macrophages. A maximum of MMP3 was observed in the CDI group at day 30. TIMP1 was below the detection limit. In this study, we demonstrated the potential of decellularization to create biocompatible porcine ureteric grafts, whereas a CDI-crosslink may facilitate the remodeling process. The use of decellularized ureteric grafts may represent a novel therapeutic method in reconstruction of ureteric defects. PMID:26157796

  13. Interleukin-22 protects intestinal stem cells from immune-mediated tissue damage and regulates sensitivity to graft vs. host disease

    PubMed Central

    Hanash, Alan M.; Dudakov, Jarrod A.; Hua, Guoqiang; O’Connor, Margaret H.; Young, Lauren F.; Singer, Natalie V.; West, Mallory L.; Jenq, Robert R.; Holland, Amanda M.; Kappel, Lucy W.; Ghosh, Arnab; Tsai, Jennifer J.; Rao, Uttam K.; Yim, Nury L.; Smith, Odette M.; Velardi, Enrico; Hawryluk, Elena; Murphy, George F.; Liu, Chen; Fouser, Lynette A.; Kolesnick, Richard; Blazar, Bruce R.; van den Brink, Marcel R.M.

    2012-01-01

    Summary Little is known about the maintenance of intestinal stem cells (ISCs) and progenitors during immune-mediated tissue damage or about the susceptibility of transplant recipients to tissue damage mediated by the donor immune system during graft vs. host disease (GVHD). We demonstrate here that deficiency of recipient-derived IL-22 increased acute GVHD tissue damage and mortality, that ISCs were eliminated during GVHD, and that ISCs as well as their downstream progenitors expressed the IL-22 receptor. Intestinal IL-22 was produced after bone marrow transplant by IL-23-responsive innate lymphoid cells (ILCs) from the transplant recipients, and intestinal IL-22 increased in response to pre-transplant conditioning. However, ILC frequency and IL-22 amounts were decreased by GVHD. Recipient IL-22 deficiency led to increased crypt apoptosis, depletion of ISCs, and loss of epithelial integrity. Our findings reveal IL-22 as a critical regulator of tissue sensitivity to GVHD and a protective factor for ISC during inflammatory intestinal damage. PMID:22921121

  14. Matching osteochondritis dissecans lesions in identical twin brothers.

    PubMed

    Richie, Lucas B; Sytsma, Mark J

    2013-09-01

    Osteochondritis dissecans is a disorder of unknown etiology that can result in fragmentation of osteochondral surfaces, most commonly of the knee, shoulder, elbow, and ankle. This may lead to sequelae of pain and an inability to participate in desired activities. Multiple theories exist as to the true cause of the disorder, but none have been fully proven. One such proposed etiology is genetic causation. Familial cases of osteochondritis dissecans are rare, yet these cases offer support to growing evidence that may support a genetic link. This article describes osteochondritis dissecans lesions of the femoral trochlea in monozygotic (identical) twins. Both twins presented with similar symptoms 1 year apart. Neither twin had any clear inciting trauma. Magnetic resonance imaging revealed osteochondral lesions in similar positions of the lateral trochlear of the same knee in both brothers. Osteochondral autograft transfer and tibial tubercle anteromedialization were performed on both patients. An identical postoperative protocol was followed, and recovery with full return to sport was comparable for the brothers. To the authors' knowledge, only 1 other case report exists of osteochondritis dissecans lesions in monozygotic twins. Although debate continues regarding the true etiology of this disorder, cases of identical twins presenting with a similar disease process are highly suggestive of a genetic component and may lead to early identification and treatment of these lesions. Continued research in the area of osteochondritis dissecans and its genetic basis is needed to completely understand this disorder. PMID:24025016

  15. Osteochondritis dissecans on the medial aspect of the humeral head

    PubMed Central

    Mima, Yuichiro; Matsumura, Noboru; Ogawa, Kiyohisa; Iwamoto, Takuji; Ochi, Kensuke; Sato, Kazuki; Toyama, Yoshiaki

    2016-01-01

    The case of a 29-year-old man who had osteochondritis dissecans on the medial aspect of the humeral head is reported. Repetitive micro-trauma at a low elevated arm position was thought to have induced the osteochondral lesion. PMID:27186062

  16. Dysplasia Epiphysealis Hemimelica Treated with Osteochondral Allograft: A Case Report

    PubMed Central

    Anthony, Chris A.; Wolf, Brian R.

    2015-01-01

    Background Dysplasia epiphysealis hemimelica (DEH), or Trevor's disease, is a developmental disorder of the pediatric skeleton characterized by asymmetric osteochondral overgrowth. Methods We present the case of a five year old boy with a two year history of right knee pain and evidence of DEH on imaging who underwent initial arthroscopic resection of his lesion with subsequent recurrence. The patient then underwent osteochondral allograft revision surgery and was asymptomatic at two year follow-up with a congruent joint surface. Results To our knowledge, this is the first reported case of a DEH lesion treated with osteochondral allograft and also the youngest reported case of osteochondral allograft placement in the literature. Conclusions Osteochondral allograft may be a viable option in DEH and other deformities of the pediatric knee. Level of Evidence Level V PMID:26361443

  17. Addressing the Potential Need for Coronary Artery Bypass Grafting After Free Tissue Transfer for Breast Reconstruction: An Algorithmic Approach.

    PubMed

    Maher, Janae L; Mahabir, Raman C; Roehl, Kendall R

    2015-08-01

    The number one cause of death in American women is heart disease. Studies have clearly shown the superiority of internal mammary artery (IMA) grafts for coronary revascularization over other conduits or intracoronary techniques. Our goal was to design an algorithm for recipient vessel selection in patients undergoing free tissue transfer breast reconstruction.A review of the literature was performed to identify potential evidence to contribute to a best-practice guideline. The lack of high-level evidence led us to create a guideline based on a workgroup consensus, expert opinion, cadaveric studies, and case reports.As we operate on older patient populations, the need for IMA use for coronary artery bypass grafting (CABG) after autologous breast reconstruction may arise more frequently. We discuss the current literature regarding recipient vessel choices and level of recipient vessel harvest in free flap breast reconstruction to help continually evolve the practices of our specialty to the potential future needs of our patients. We also present a best-practice decision algorithm for vessel selection and harvest, as well as a sample case of CABG using the left IMA 35 days after previous autologous breast reconstruction using the left IMA.As the number of patients we operate on who may later require their IMA for CABG increases, so too must our understanding of the implications of our selection of recipient vessels for free autologous breast reconstruction. PMID:26165568

  18. The saddle connective tissue graft: a periodontal plastic surgery technique to obtain soft tissue coronal gain on immediate implants. A case report.

    PubMed

    González, David; Cabello, Gustavo; Olmos, Gema; Niñoles, Carlos L

    2015-01-01

    Based on recent studies regarding the advantages of flapless immediate implants on the maintenance of the soft tissue architecture (especially at papillae level) in those situations where it is necessary to extract an anterior tooth, this case report describes a clinical procedure designed to replace a hopeless central incisor (2.1) showing root resorption adjacent to an implant-supported crown (1.1), whose gingival margin is 2 mm coronal regarding the hopeless tooth to be replaced. After the extraction of the hopeless tooth (2.1), a flapless immediate implant was placed. The implant-bone gap was then filled with bone substitute and a palatal connective tissue graft was placed ad modum saddle extending at buccal level from apical to the mucogingival line, sealing the socket and extending until 6 mm at palatal level ad modum saddle. This procedure allowed symmetry of the soft tissue margins between the two implants (1.1 and 2.1) to be obtained as well as the preservation of the inter-implant papillae (1.1). PMID:26171446

  19. Fabrication and development of artificial osteochondral constructs based on cancellous bone/hydrogel hybrid scaffold.

    PubMed

    Song, Kedong; Li, Liying; Yan, Xinyu; Zhang, Yu; Li, Ruipeng; Wang, Yiwei; Wang, Ling; Wang, Hong; Liu, Tianqing

    2016-06-01

    Using tissue engineering techniques, an artificial osteochondral construct was successfully fabricated to treat large osteochondral defects. In this study, porcine cancellous bones and chitosan/gelatin hydrogel scaffolds were used as substitutes to mimic bone and cartilage, respectively. The porosity and distribution of pore size in porcine bone was measured and the degradation ratio and swelling ratio for chitosan/gelatin hydrogel scaffolds was also determined in vitro. Surface morphology was analyzed with the scanning electron microscope (SEM). The physicochemical properties and the composition were tested by using an infrared instrument. A double layer composite scaffold was constructed via seeding adipose-derived stem cells (ADSCs) induced to chondrocytes and osteoblasts, followed by inoculation in cancellous bones and hydrogel scaffolds. Cell proliferation was assessed through Dead/Live staining and cellular activity was analyzed with IpWin5 software. Cell growth, adhesion and formation of extracellular matrix in composite scaffolds blank cancellous bones or hydrogel scaffolds were also analyzed. SEM analysis revealed a super porous internal structure of cancellous bone scaffolds and pore size was measured at an average of 410 ± 59 μm while porosity was recorded at 70.6 ± 1.7 %. In the hydrogel scaffold, the average pore size was measured at 117 ± 21 μm and the porosity and swelling rate were recorded at 83.4 ± 0.8 % and 362.0 ± 2.4 %, respectively. Furthermore, the remaining hydrogel weighed 80.76 ± 1.6 % of the original dry weight after hydration in PBS for 6 weeks. In summary, the cancellous bone and hydrogel composite scaffold is a promising biomaterial which shows an essential physical performance and strength with excellent osteochondral tissue interaction in situ. ADSCs are a suitable cell source for osteochondral composite reconstruction. Moreover, the bi-layered scaffold significantly enhanced cell proliferation compared to the cells seeded on

  20. Osteochondral interface generation by rabbit bone marrow stromal cells and osteoblasts coculture.

    PubMed

    Chen, Kelei; Teh, Thomas Kok Hiong; Ravi, Sujata; Toh, Siew Lok; Goh, James Cho Hong

    2012-09-01

    Physiological osteochondral interface regeneration is a significant challenge. This study aims to investigate the effect of the coculture of chondrogenic rabbit bone marrow stromal cells (rBMSCs) with rabbit osteoblasts in a specially designed two-dimensional (2D)-three-dimensional (3D) co-interface culture to develop the intermediate osteochondral region in vitro. The 2D-3D coculture system was set up by first independently culturing chondrogenic rBMSCs on a scaffold and osteoblasts in cell culture plates, and subsequently placed in contact and cocultured. As control, samples not cocultured with osteoblasts were used. The regulatory effects exerted by osteoblasts on chondrogenic rBMSCs were quantified by real-time polymerase chain reaction. To study the effect of coculture on cells located in different parts of the scaffold, samples were separated into two parts and significantly different gene expression patterns were found between them. In comparison with the control group, a significant moderate downregulation of chondrogenic marker genes, such as Collagen II and Aggrecan was observed. However, the Sox-9 and Collagen I expression increased. More importantly, chondrogenic rBMSCs in the coculture system were shown to form the osteochondral interface layer by expressing calcified cartilage zone specific extracellular matrix marker Collagen X and the hypertrophic chondrocyte marker MMP-13, which were not observed in the control group. Specifically, only the chondrogenic rBMSC layer in contact with the osteoblasts expressed Collagen X and MMP-13, indicating the positive influence of the coculture upon interface formation. Biochemical analyses, histology results, and immunohistochemical staining further supported this observation. In conclusion, this study revealed that specific regulatory stimulations from osteoblasts in the 2D-3D interface coculture system could induce the formation of ostochondral interface for the purpose of osteochondral tissue engineering. PMID

  1. Matrix-associated autologous chondrocyte transplantation combined with iliac crest bone graft for reconstruction of talus necrosis due to villonodular synovitis.

    PubMed

    Dickschas, Jörg; Welsch, Götz; Strecker, Wolf; Schöffl, Volker

    2012-01-01

    We report the case of a 24-year-old driving instructor with osteonecrosis of the talus and a large articular cartilage and osseous defect. The cystic lesion was caused by villonodular synovitis. After magnetic resonance imaging detection and arthoscopic analysis, the defect was filled with a bone graft, followed by matrix-associated autologous chondrocyte transplantation (MACT) combined with a total synovectomy. In general, lesions similar to the one described in this case are treated using osteochondral autografts, but in our case the osseous defect was too large to perform an osteochondral autograft. Our choice of treatment with an iliac crest bone graft combined with a MACT simultaneously has not yet been published, as far as we know. The patient returned to his former activities of daily living and sport activities, without restrictions or complaints, and with only a slight deficit in range of motion. Morphological and biochemical magnetic resonance imaging 12 months after surgery showed excellent bone healing with no intraosseous edema. The MACT resulted in a good clinical outcome, with 100% defect filling and excellent integration and surface and signal intensity of the cartilage repair tissue, and the American Orthopaedic Foot and Ankle Society Ankle-Hindfoot score increased from 47 to 79 points. PMID:22104171

  2. Histological characterization and quantification of cellular events following neural and fibroblast(-like) stem cell grafting in healthy and demyelinated CNS tissue.

    PubMed

    Praet, Jelle; Santermans, Eva; Reekmans, Kristien; de Vocht, Nathalie; Le Blon, Debbie; Hoornaert, Chloé; Daans, Jasmijn; Goossens, Herman; Berneman, Zwi; Hens, Niel; Van der Linden, Annemie; Ponsaerts, Peter

    2014-01-01

    Preclinical animal studies involving intracerebral (stem) cell grafting are gaining popularity in many laboratories due to the reported beneficial effects of cell grafting on various diseases or traumata of the central nervous system (CNS). In this chapter, we describe a histological workflow to characterize and quantify cellular events following neural and fibroblast(-like) stem cell grafting in healthy and demyelinated CNS tissue. First, we provide standardized protocols to isolate and culture eGFP(+) neural and fibroblast(-like) stem cells from embryonic mouse tissue. Second, we describe flow cytometric procedures to determine cell viability, eGFP transgene expression, and the expression of different stem cell lineage markers. Third, we explain how to induce reproducible demyelination in the CNS of mice by means of cuprizone administration, a validated mouse model for human multiple sclerosis. Fourth, the technical procedures for cell grafting in the CNS are explained in detail. Finally, an optimized and validated workflow for the quantitative histological analysis of cell graft survival and endogenous astroglial and microglial responses is provided. PMID:25173390

  3. Wnt/β-catenin signaling of cartilage canal and osteochondral junction chondrocytes and full thickness cartilage in early equine osteochondrosis.

    PubMed

    Kinsley, Marc A; Semevolos, Stacy A; Duesterdieck-Zellmer, Katja F

    2015-10-01

    The objective of this study was to elucidate gene and protein expression of Wnt signaling molecules in chondrocytes of foals having early osteochondrosis (OC) versus normal controls. The hypothesis was that increased expression of components of Wnt signaling pathway in osteochondral junction (OCJ) and cartilage canal (CC) chondrocytes would be found in early OC when compared to controls. Paraffin-embedded osteochondral samples (7 OC, 8 normal) and cDNA from whole cartilage (7 OC, 10 normal) and chondrocytes surrounding cartilage canals and osteochondral junctions captured with laser capture microdissection (4 OC, 6 normal) were obtained from femoropatellar joints of 17 immature horses. Equine-specific Wnt signaling molecule mRNA expression levels were evaluated by two-step real-time qPCR. Spatial tissue protein expression of β-catenin, Wnt-11, Wnt-4, and Dkk-1 was determined by immunohistochemistry. There was significantly decreased Wnt-11 and increased β-catenin, Wnt-5b, Dkk-1, Lrp6, Wif-1, Axin1, and SC-PEP gene expression in early OC cartilage canal chondrocytes compared to controls. There was also significantly increased β-catenin gene expression in early OC osteochondral junction chondrocytes compared to controls. Based on this study, abundant gene expression differences in OC chondrocytes surrounding cartilage canals suggest pathways associated with catabolism and inhibition of chondrocyte maturation are targeted in early OC pathogenesis. PMID:25676127

  4. Osteochondral regeneration using an oriented nanofiber yarn-collagen type I/hyaluronate hybrid/TCP biphasic scaffold.

    PubMed

    Liu, Shen; Wu, Jinglei; Liu, Xudong; Chen, Desheng; Bowlin, Gary L; Cao, Lei; Lu, Jianxi; Li, Fengfeng; Mo, Xiumei; Fan, Cunyi

    2015-02-01

    Osteochondral defects affect both the articular cartilage and the underlying subchondral bone, but poor osteochondral regeneration is still a daunting challenge. Although the tissue engineering technology provides a promising approach for osteochondral repair, an ideal biphasic scaffold is in high demand with regards to proper biomechanical strength. In this study, an oriented poly(l-lacticacid)-co-poly(ε-caprolactone) P(LLA-CL)/collagen type I(Col-I) nanofiber yarn mesh, fabricated by dynamic liquid electrospinning served as a skeleton for a freeze-dried Col-I/Hhyaluronate (HA) chondral phase (SPONGE) to enhance the mechanical strength of the scaffold. In vitro results show that the Yarn Col-I/HA hybrid scaffold (Yarn-CH) can allow the cell infiltration like sponge scaffolds. Using porous beta-tricalcium phosphate (TCP) as the osseous phase, the Yarn-CH/TCP biphasic scaffold was then assembled by freeze drying. After combination of bone marrow mesenchymal stem cells, the biphasic complex was successfully used to repair the osteochondral defects in a rabbit model with greatly improved repairing scores and compressive modulus. PMID:24771686

  5. Comparison of ADM and Connective Tissue Graft as the Membrane in Class II Furcation Defect Regeneration: A Randomized Clinical Trial

    PubMed Central

    Esfahanian, Vahid; Farhad, Shirin; Sadighi Shamami, Mehrnaz

    2014-01-01

    Background and aims. Furcally-involved teeth present unique challenges to the success of periodontal therapy and influence treatment outcomes. This study aimed to assess to compare use of ADM and connective tissue membrane in class II furcation defect regeneration. Materials and methods. 10 patient with 2 bilaterally class II furcation defects in first and/or second maxilla or man-dibular molar without interproximal furcation involvement, were selected. Four weeks after initial phase of treatment, before and thorough the surgery pocket depth (PD), clinical attachment level to stent (CAL-S), free gingival margin to stent(FGM-S) , crestal bone to stent (Crest-S), horizontal defect depth to stent (HDD-S) and vertical defect depth to stent (VDD-S) and crestal bone to defect depth measured from stent margin. Thereafter, one side randomly treated using connective tissue and DFDBA (study group) and opposite side received ADM and DFDBA (control group). After 6 months, soft and hard tissue parameters measured again in re-entry. Results. Both groups presented improvements after therapies (P & 0.05). No inter-group differences were seen in PD re-duction (P = 0.275), CAL gain (P = 0.156), free gingival margin (P = 0.146), crest of the bone (P = 0.248), reduction in horizontal defects depth (P = 0.139) and reduction in vertical defects depth (P = 0.149). Conclusion. Both treatments modalities have potential of regeneration without any adverse effect on healing process. Connective tissue grafts did not have significant higher bone fill compared to that of ADM. PMID:25093054

  6. Insulin-like Growth Factor-I and Slow, Bi-directional Perfusion Enhance the Formation of Tissue-Engineered Cardiac Grafts

    PubMed Central

    Cheng, Mingyu; Moretti, Matteo; Engelmayr, George C.

    2009-01-01

    Biochemical and mechanical signals enabling cardiac regeneration can be elucidated using in vitro tissue-engineering models. We hypothesized that insulin-like growth factor-I (IGF) and slow, bi-directional perfusion could act independently and interactively to enhance the survival, differentiation, and contractile performance of tissue-engineered cardiac grafts. Heart cells were cultured on three-dimensional porous scaffolds in medium with or without supplemental IGF and in the presence or absence of slow, bi-directional perfusion that enhanced transport and provided shear stress. Structural, molecular, and electrophysiologic properties of the resulting grafts were quantified on culture day 8. IGF had independent, beneficial effects on apoptosis (p < 0.01), cellular viability (p < 0.01), contractile amplitude (p < 0.01), and excitation threshold (p < 0.01). Perfusion independently affected the four aforementioned parameters and also increased amounts of cardiac troponin-I (p < 0.01), connexin-43 (p < 0.05), and total protein (p < 0.01) in the grafts. Interactive effects of IGF and perfusion on apoptosis were also present (p < 0.01). Myofibrillogenesis and spontaneous contractility were present only in grafts cultured with perfusion, although contractility was inducible by electrical field stimulation of grafts from all groups. Our findings demonstrate that multi-factorial stimulation of tissue-engineered cardiac grafts using IGF and perfusion resulted in independent and interactive effects on heart cell survival, differentiation, and contractility. PMID:18759675

  7. Covalent immobilization of stem cell inducing/recruiting factor and heparin on cell-free small-diameter vascular graft for accelerated in situ tissue regeneration.

    PubMed

    Shafiq, Muhammad; Jung, Youngmee; Kim, Soo Hyun

    2016-06-01

    The development of cell-free vascular grafts has tremendous potential for tissue engineering. However, thrombus formation, less-than-ideal cell infiltration, and a lack of growth potential limit the application of electrospun scaffolds for in situ tissue-engineered vasculature. To overcome these challenges, here we present development of an acellular tissue-engineered vessel based on electrospun poly(L-lactide-co-ɛ-caprolactone) scaffolds. Heparin was conjugated to suppress thrombogenic responses, and substance P (SP) was immobilized to recruit host cells. SP was released in a sustained manner from scaffolds and recruited human bone marrow-derived mesenchymal stem cells. The biocompatibility and biological performance of the grafts were evaluated by in vivo experiments involving subcutaneous scaffold implantation in Sprague-Dawley rats (n = 12) for up to 4 weeks. Histological analysis revealed a higher extent of accumulative host cell infiltration, neotissue formation, collagen deposition, and elastin deposition in scaffolds containing either SP or heparin/SP than in the control groups. We also observed the presence of a large number of laminin-positive blood vessels, von Willebrand factor (vWF(+) ) cells, and alpha smooth muscle actin-positive cells in the explants containing SP and heparin/SP. Additionally, SP and heparin/SP grafts showed the existence of CD90(+) and CD105(+) MSCs and induced a large number of M2 macrophages to infiltrate the graft wall compared with that observed with the control group. Our cell-free grafts could enhance vascular regeneration by endogenous cell recruitment and by mediating macrophage polarization into the M2 phenotype, suggesting that these constructs may be a promising cell-free graft candidate and are worthy of further in vivo evaluation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1352-1371, 2016. PMID:26822178

  8. Phthalate esters affect maturation and function of primate testis tissue ectopically grafted in mice

    PubMed Central

    Rodriguez-Sosa, Jose R; Bondareva, Alla; Tang, Lin; Avelar, Gleide F.; Coyle, Krysta M.; Modelski, Mark; Alpaugh, Whitney; Conley, Alan; Wynne-Edwards, Katherine; França, Luiz R; Meyers, Stuart; Dobrinski, Ina

    2014-01-01

    Di-n-Butyl (DBP) and Di-(2-EthylHexyl) (DEHP) phthalates can leach from daily-use products resulting in environmental exposure. In male rodents, phthalate exposure results in reproductive effects. To evaluate effects on the immature primate testis, testis fragments from 6-month-old rhesus macaques were grafted subcutaneously to immune-deficient mice, which were exposed to 0, 10, or 500 mg/kg of DBP or DEHP for 14 weeks or 28 weeks (DBP only). DBP exposure reduced the expression of key steroidogenic genes, indicating that Leydig cell function was compromised. Exposure to 500 mg/kg impaired tubule formation and germ cell differentiation and reduced numbers of spermatogonia. Exposure to 10 mg/kg did not affect development, but reduced Sertoli cell number and resulted in increased expression of inhibin B. Exposure to DEHP for 14 week also affected steroidogenic genes expression. Therefore, long-term exposure to phthalate esters affected development and function of the primate testis in a time and dosage dependent manner. PMID:25450860

  9. Immunoisolation to prevent tissue graft rejection: Current knowledge and future use.

    PubMed

    David, Anu; Day, James; Shikanov, Ariella

    2016-05-01

    This review focuses on the concept of immunoisolation and how this method has evolved over the last few decades. The concept of immunoisolation came out of the need to protect allogeneic transplant tissue from the host immune system and avoid systemic side effects of immunosuppression. The latter remains a significant hurdle in clinical translation of using tissue transplants for restoring endocrine function in diabetes, growth hormone deficiency, and other conditions. Herein, we review the most significant works studying the use of hydrogels, specifically alginate and poly (ethylene glycol), and membranes for immunoisolation and discuss how this approach can be applied in reproductive biology. PMID:27188513

  10. The influence of stromal cells on the pigmentation of tissue-engineered dermo-epidermal skin grafts.

    PubMed

    Biedermann, Thomas; Böttcher-Haberzeth, Sophie; Klar, Agnieszka S; Widmer, Daniel S; Pontiggia, Luca; Weber, Andreas D; Weber, Daniel M; Schiestl, Clemens; Meuli, Martin; Reichmann, Ernst

    2015-03-01

    It has been shown in vitro that melanocyte proliferation and function in palmoplantar skin is regulated by mesenchymal factors derived from fibroblasts. In this study, we investigated in vivo the influence of mesenchymal-epithelial interactions in human tissue-engineered skin substitutes reconstructed from palmar- and nonpalmoplantar-derived fibroblasts. Tissue-engineered dermo-epidermal analogs based on collagen type I hydrogels were populated with either human palmar or nonpalmoplantar fibroblasts and seeded with human nonpalmoplantar-derived melanocytes and keratinocytes. These skin substitutes were transplanted onto full-thickness skin wounds of immunoincompetent rats. Four weeks after transplantation the development of skin color was measured and grafts were excised and analyzed with regard to epidermal characteristics, in particular melanocyte number and function. Skin substitutes containing palmar-derived fibroblasts in comparison to nonpalmoplantar-derived fibroblasts showed (a) a significantly lighter pigmentation; (b) a reduced amount of epidermal melanin granules; and (c) a distinct melanosome expression. However, the number of melanocytes in the basal layer remained similar in both transplantation groups. These findings demonstrate that human palmar fibroblasts regulate the function of melanocytes in human pigmented dermo-epidermal skin substitutes after transplantation, whereas the number of melanocytes remains constant. This underscores the influence of site-specific stromal cells and their importance when constructing skin substitutes for clinical application. PMID:25300246

  11. The Influence of Stromal Cells on the Pigmentation of Tissue-Engineered Dermo-Epidermal Skin Grafts

    PubMed Central

    Biedermann, Thomas; Böttcher-Haberzeth, Sophie; Klar, Agnieszka S.; Widmer, Daniel S.; Pontiggia, Luca; Weber, Andreas D.; Weber, Daniel M.; Schiestl, Clemens; Meuli, Martin

    2015-01-01

    It has been shown in vitro that melanocyte proliferation and function in palmoplantar skin is regulated by mesenchymal factors derived from fibroblasts. In this study, we investigated in vivo the influence of mesenchymal–epithelial interactions in human tissue-engineered skin substitutes reconstructed from palmar- and nonpalmoplantar-derived fibroblasts. Tissue-engineered dermo-epidermal analogs based on collagen type I hydrogels were populated with either human palmar or nonpalmoplantar fibroblasts and seeded with human nonpalmoplantar-derived melanocytes and keratinocytes. These skin substitutes were transplanted onto full-thickness skin wounds of immunoincompetent rats. Four weeks after transplantation the development of skin color was measured and grafts were excised and analyzed with regard to epidermal characteristics, in particular melanocyte number and function. Skin substitutes containing palmar-derived fibroblasts in comparison to nonpalmoplantar-derived fibroblasts showed (a) a significantly lighter pigmentation; (b) a reduced amount of epidermal melanin granules; and (c) a distinct melanosome expression. However, the number of melanocytes in the basal layer remained similar in both transplantation groups. These findings demonstrate that human palmar fibroblasts regulate the function of melanocytes in human pigmented dermo-epidermal skin substitutes after transplantation, whereas the number of melanocytes remains constant. This underscores the influence of site-specific stromal cells and their importance when constructing skin substitutes for clinical application. PMID:25300246

  12. Fabrication and characterisation of biomimetic, electrospun gelatin fibre scaffolds for tunica media-equivalent, tissue engineered vascular grafts.

    PubMed

    Elsayed, Y; Lekakou, C; Labeed, F; Tomlins, P

    2016-04-01

    It is increasingly recognised that biomimetic, natural polymers mimicking the extracellular matrix (ECM) have low thrombogenicity and functional motifs that regulate cell-matrix interactions, with these factors being critical for tissue engineered vascular grafts especially grafts of small diameter. Gelatin constitutes a low cost substitute of soluble collagen but gelatin scaffolds so far have shown generally low strength and suture retention strength. In this study, we have devised the fabrication of novel, electrospun, multilayer, gelatin fibre scaffolds, with controlled fibre layer orientation, and optimised gelatin crosslinking to achieve not only compliance equivalent to that of coronary artery but also for the first time strength of the wet tubular acellular scaffold (swollen with absorbed water) same as that of the tunica media of coronary artery in both circumferential and axial directions. Most importantly, for the first time for natural scaffolds and in particular gelatin, high suture retention strength was achieved in the range of 1.8-1.94 N for wet acellular scaffolds, same or better than that for fresh saphenous vein. The study presents the investigations to relate the electrospinning process parameters to the microstructural parameters of the scaffold, which are further related to the mechanical performance data of wet, crosslinked, electrospun scaffolds in both circumferential and axial tubular directions. The scaffolds exhibited excellent performance in human smooth muscle cell (SMC) proliferation, with SMCs seeded on the top surface adhering, elongating and aligning along the local fibres, migrating through the scaffold thickness and populating a transverse distance of 186 μm and 240 μm 9 days post-seeding for scaffolds of initial dry porosity of 74 and 83%, respectively. PMID:26838874

  13. Osteochondritis dissecans of the capitellum in adolescents

    PubMed Central

    van Bergen, Christiaan JA; van den Ende, Kimberly IM; ten Brinke, Bart; Eygendaal, Denise

    2016-01-01

    Osteochondritis dissecans (OCD) is a disorder of articular cartilage and subchondral bone. In the elbow, an OCD is localized most commonly at the humeral capitellum. Teenagers engaged in sports that involve repetitive stress on the elbow are at risk. A high index of suspicion is warranted to prevent delay in the diagnosis. Plain radiographs may disclose the lesion but computed tomography and magnetic resonance imaging are more accurate in the detection of OCD. To determine the best treatment option it is important to differentiate between stable and unstable OCD lesions. Stable lesions can be initially treated nonoperatively with elbow rest or activity modification and physical therapy. Unstable lesions and stable lesions not responding to conservative therapy require a surgical approach. Arthroscopic debridement and microfracturing has become the standard initial procedure for treatment of capitellar OCD. Numerous other surgical options have been reported, including internal fixation of large fragments and osteochondral autograft transfer. The aim of this article is to provide a current concepts review of the etiology, clinical presentation, diagnosis, treatment, and outcomes of elbow OCD. PMID:26925381

  14. Osteochondritis dissecans of the temporomandibular joint.

    PubMed

    Campos, P S F; Freitas, C E; Pena, N; Gonzalez, M O D; Almeida, S M; Mariz, A C R; Lorens, F G L

    2005-05-01

    A case is reported of a 43-year-old female patient presenting bilateral osteochondritis dissecans (OCD) of the temporomandibular joint (TMJ), in different stages for each side, associated with avascular necrosis (AVN) of the right condyle. Additionally observed was anterior disk displacement without reduction for both sides. We have proposed an adaptation of the previous classification of OCD for cases affecting the TMJ. We have also stressed the fundamental role of panoramic radiography on the diagnosis of stage 3 and stage 4 OCD of the TMJ. In relation to MRI, we have recommended sagittal (slice thickness of 2 mm) and coronal (slice thickness of 1 mm) fast spin-echo proton density-weighted sequences to better identify bone lesions (stage 1 and 2) and also localize osteochondral loose bodies; and coronal (slice thickness of 1 mm) fat-suppressed fast spin-echo T2 weighted sequence to better evaluate OCD (stable or unstable) and the features of the occasionally associated AVN (acute or chronic). PMID:15897292

  15. In vitro generation of whole osteochondral constructs using rabbit bone marrow stromal cells, employing a two-chambered co-culture well design.

    PubMed

    Chen, Kelei; Ng, Kian Siang; Ravi, Sujata; Goh, James C H; Toh, Siew Lok

    2016-04-01

    The regeneration of whole osteochondral constructs with a physiological structure has been a significant issue, both clinically and academically. In this study, we present a method using rabbit bone marrow stromal cells (BMSCs) cultured on a silk-RADA peptide scaffold in a specially designed two-chambered co-culture well for the generation of multilayered osteochondral constructs in vitro. This specially designed two-chambered well can simultaneously provide osteogenic and chondrogenic stimulation to cells located in different regions of the scaffold. We demonstrated that this co-culture approach could successfully provide specific chemical stimulation to BMSCs located on different layers within a single scaffold, resulting in the formation of multilayered osteochondral constructs containing cartilage-like and subchondral bone-like tissue, as well as the intermediate osteochondral interface. The cells in the intermediate region were found to be hypertrophic chondrocytes, embedded in a calcified extracellular matrix containing glycosaminoglycans and collagen types I, II and X. In conclusion, this study provides a single-step approach that highlights the feasibility of rabbit BMSCs as a single-cell source for multilayered osteochondral construct generation in vitro. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23495238

  16. Image-Guided Techniques Improve the Short-Term Outcome of Autologous Osteochondral Cartilage Repair Surgeries

    PubMed Central

    Devlin, Steven M.; Hurtig, Mark B.; Waldman, Stephen D.; Rudan, John F.; Bardana, Davide D.; Stewart, A. James

    2013-01-01

    Objective: Autologous osteochondral cartilage repair is a valuable reconstruction option for cartilage defects, but the accuracy to harvest and deliver osteochondral grafts remains problematic. We investigated whether image-guided methods (optically guided and template guided) can improve the outcome of these procedures. Design: Fifteen sheep were operated to create traumatic chondral injuries in each knee. After 4 months, the chondral defect in one knee was repaired using (a) conventional approach, (b) optically guided method, or (c) template-guided method. For both image-guided groups, harvest and delivery sites were preoperatively planned using custom-made software. During optically guided surgery, instrument position and orientation were tracked and superimposed onto the surgical plan. For the template-guided group, plastic templates were manufactured to allow an exact fit between template and the joint anatomy. Cylindrical holes within the template guided surgical tools according to the plan. Three months postsurgery, both knees were harvested and computed tomography scans were used to compare the reconstructed versus the native pre-injury joint surfaces. For each repaired defect, macroscopic (International Cartilage Repair Society [ICRS]) and histological repair (ICRS II) scores were assessed. Results: Three months after repair surgery, both image-guided surgical approaches resulted in significantly better histology scores compared with the conventional approach (improvement by 55%, P < 0.02). Interestingly, there were no significant differences found in cartilage surface reconstruction and macroscopic scores between the image-guided and the conventional surgeries. PMID:26069658

  17. Pulsed High–Intensity-focused US and Tissue Plasminogen Activator (TPA) Versus TPA Alone for Thrombolysis of Occluded Bypass Graft in Swine

    PubMed Central

    Abi-Jaoudeh, Nadine; Pritchard, William F.; Amalou, Hayet; Linguraru, Marius; Chiesa, Oscar A.; Adams, Joshua D.; Gacchina, Carmen; Wesley, Robert; Maruvada, Subha; McDowell, Briana; Frenkel, Victor; Karanian, John W.; Wood, Bradford J.

    2012-01-01

    Purpose Prosthetic arteriovenous or arterial-arterial bypass grafts can thrombose and be resistant to revascularization. A thrombosed bypass graft model was created to evaluate the potential therapeutic enhancement and safety profile of pulsed high-intensity-focused ultrasound (pHIFU) on pharmaceutical thrombolysis. Materials and Methods In swine, a right carotid-carotid expanded polytetrafluoroethylene bypass graft was surgically constructed, containing a 40% stenosis at its distal end to induce graft thrombosis. The revascularization procedure was performed 7 days after surgery. After model development and dose response experiments (n = 11), two cohorts were studied: pHIFU with tissue plasminogen activator (TPA; n = 4) and sham pHIFU with TPA (n = 3). The experiments were identical in both groups except no energy was delivered in the sham pHIFU group. Serial angiograms were obtained in all cases. The area of graft opacified by contrast medium on angiograms was quantified with digital image processing software. A blinded reviewer calculated the change in the graft area opacified by contrast medium and expressed it as a percentage, representing percentage of thrombolysis. Results Combining pHIFU with 0.5 mg of TPA resulted in a 52% ± 4% increase in thrombolysis on angiograms obtained at 30 minutes, compared with a 9% ± 14% increase with sham pHIFU and 0.5 mg TPA (P = .003). Histopathologic examination demonstrated no differences between the groups. Conclusions Thrombolysis of occluded bypass grafts was significantly increased when combining pHIFU and TPA versus sham pHIFU and TPA. These results suggest that application of pHIFU may augment thrombolysis with a reduced time and dose. PMID:22609287

  18. Development of a Comprehensive Osteochondral Allograft MRI Scoring System (OCAMRISS) With Histopathologic, Micro–Computed Tomography, and Biomechanical Validation

    PubMed Central

    Pallante-Kichura, Andrea L.; Bae, Won C.; Du, Jiang; Statum, Sheronda; Wolfson, Tanya; Gamst, Anthony C.; Cory, Esther; Amiel, David; Bugbee, William D.; Sah, Robert L.; Chung, Christine B.

    2014-01-01

    Objective: To describe and apply a semiquantitative MRI scoring system for multifeature analysis of cartilage defect repair in the knee by osteochondral allografts and to correlate this scoring system with histopathologic, micro–computed tomography (µCT), and biomechanical reference standards using a goat repair model. Design: Fourteen adult goats had 2 osteochondral allografts implanted into each knee: one in the medial femoral condyle and one in the lateral trochlea. At 12 months, goats were euthanized and MRI was performed. Two blinded radiologists independently rated 9 primary features for each graft, including cartilage signal, fill, edge integration, surface congruity, calcified cartilage integrity, subchondral bone plate congruity, subchondral bone marrow signal, osseous integration, and presence of cystic changes. Four ancillary features of the joint were also evaluated, including opposing cartilage, meniscal tears, synovitis, and fat-pad scarring. Comparison was made with histologic and µCT reference standards as well as biomechanical measures. Interobserver agreement and agreement with reference standards was assessed. Cohen’s κ, Spearman’s correlation, and Kruskal-Wallis tests were used as appropriate. Results: There was substantial agreement (κ > 0.6, P < 0.001) for each MRI feature and with comparison against reference standards, except for cartilage edge integration (κ = 0.6). There was a strong positive correlation between MRI and reference standard scores (ρ = 0.86, P < 0.01). Osteochondral allograft MRI scoring system was sensitive to differences in outcomes between the types of allografts. Conclusions: We have described a comprehensive MRI scoring system for osteochondral allografts and have validated this scoring system with histopathologic and µCT reference standards as well as biomechanical indentation testing. PMID:24489999

  19. The Maturation of Synthetic Scaffolds for Osteochondral Donor Sites of the Knee

    PubMed Central

    Bedi, Asheesh; Foo, Li Foong; Williams, Riley J.; Potter, Hollis G.

    2010-01-01

    Objective: The purpose of this study was to analyze the morphological imaging characteristics and incorporation of TruFit bone graft substitute (BGS) plugs using cartilage-sensitive magnetic resonance imaging (MRI) and quantitative T2 mapping. Design: Twenty-six patients (mean age, 28.72 years; range, 11-56 years) underwent osteochondral autologous transplantation (OATS) for chondral defects with filling of the knee joint donor sites using Trufit BGS plugs. The mean follow-up interval between implantation and MRI analysis was 21.3 months (range, 6-39 months). During this period, 43 cartilage-sensitive and 25 quantitative T2-mapping MRI studies were performed. The donor sites were assessed for plug and interface morphology, displacement, hypertrophy, subchondral edema, presence of bony overgrowth, percentage fill, and degree of incorporation. T2 relaxation times were measured for the superficial and deep layers of the repair tissue. A linear regression and correlational analysis was performed with Bonferroni correction, and P < 0.05 was defined as significant. Results: Longitudinal analysis revealed favorable plug appearance at early follow-up (≤6 months), with 75% of plugs demonstrating flush morphology and 78% demonstrating near complete to complete fill. Plug appearance deteriorated at intermediate follow-up (~12 months), with only 26% of plugs demonstrating flush morphology and 52% with near complete or complete fill. Plug appearance substantially improved with longer follow-up (≥16 months), with 70% of plugs demonstrating flush morphology and 90% demonstrating near complete or complete fill. Interface resorption was common at ~12 months (P < 0.0001) and was associated with older age (P = 0.01) or a single-plug configuration (P = 0.04). T2 values for the repair cartilage approached that of normal cartilage with increasing duration after surgery (P < 0.004), more so for single- compared with multiple-plug configurations (P = 0.03). Conclusions: The Trufit BGS

  20. OSTEOCHONDRAL INTERFACE REGENERATION OF THE RABBIT KNEE WITH MACROSCOPIC GRADIENTS OF BIOACTIVE SIGNALS

    PubMed Central

    Dormer, Nathan H.; Singh, Milind; Zhao, Liang; Mohan, Neethu; Berkland, Cory J.; Detamore, Michael S.

    2011-01-01

    To date, most interfacial tissue engineering approaches have utilized stratified designs, in which there are two or more discrete layers comprising the interface. Continuously-graded interfacial designs, where there is no discrete transition from one tissue type to another, are gaining attention as an alternative to stratified designs. Given that osteochondral regeneration holds the potential to enhance cartilage regeneration by leveraging the healing capacity of the underlying bone, we endeavored to introduce a continuously graded approach to osteochondral regeneration. The purpose of this study was thus to evaluate the performance of a novel gradient-based scaffolding approach to regenerate osteochondral defects in the New Zealand White rabbit femoral condyle. Bioactive plugs were constructed from poly(d,l-lactic-co-glycolic acid) (PLGA) microspheres with a continuous gradient transition between cartilage-promoting and bone-promoting growth factors. At six and 12 weeks of healing, results suggested that the implants provided support for the neo-synthesized tissue, and the gradient in bioactive signaling may have been beneficial for bone and cartilage regeneration compared to the blank control implant, as evidenced by histology. In addition, the effects of pre-seeding gradient scaffolds with umbilical cord mesenchymal stromal cells (UCMSCs) from the Wharton’s jelly of New Zealand White rabbits were evaluated. Results indicated that there may be regenerative benefits to pre-localizing UCMSCs within scaffold interiors. The inclusion of bioactive factors in a gradient-based scaffolding design is a promising new treatment strategy for defect repair in the femoral condyle. PMID:22009693

  1. Biologically engineered protein-graft-poly(ethylene glycol) hydrogels: A cell-adhesive and plasmin-degradable biosynthetic material for tissue repair

    NASA Astrophysics Data System (ADS)

    Halstenberg, Sven

    2002-01-01

    The goal of the research presented in this dissertation was to create a biomimetic artificial material that exhibits functions of extracellular matrix relevant for improved nerve regeneration. Neural adhesion peptides were photoimmobilized on highly crosslinked poly(ethylene glycol)-based substrates that were otherwise non-adhesive. Neurons adhered in two-dimensional patterns for eleven hours, but no neurites extended. To enable neurite extension and nerve regeneration in three dimensions, and to address the need for specifically cell adhesive and cell degradable materials for clinical applications in tissue repair in general, an artificial protein was recombinantly expressed and purified that consisted of a repeating amino acid sequence based on fibrinogen and anti-thrombin III. The recombinant protein contained integrin-binding RGD sites, plasmin degradation sites, heparin binding sites, and six thiol-containing cysteine residues as grafting sites for poly(ethylene glycol) diacrylate via Michael-type conjugate addition. The resulting protein-graft-poly(ethylene glycol)acrylates were crosslinked by photopolymerization to form hydrogels. Although three-dimensional, RGD mediated and serine protease-dependent ingrowth of human fibroblasts into protein-graft-poly(ethylene glycol) hydrogels occurred, only surface neurite outgrowth was observed from chick dorsal root ganglia. Axonal outgrowth depended on the concentration of matrix-bound heparin, suggesting that improved mechanical strength of the hydrogels and possible immobilization of neuroactive factors due to the presence of heparin promoted neurite outgrowth. Together, the above results show that specific biological functions can be harnessed by protein-graft-poly(ethylene glycol) hydrogels to serve as matrices for tissue repair and regeneration. In particular, the two design objectives, specific cell adhesion and degradability by cell-associated proteases, were fulfilled by the material. In the future, this and

  2. Antibacterial and conductive injectable hydrogels based on quaternized chitosan-graft-polyaniline/oxidized dextran for tissue engineering.

    PubMed

    Zhao, Xin; Li, Peng; Guo, Baolin; Ma, Peter X

    2015-10-15

    Biomaterials with injectability, conductivity and antibacterial effect simultaneously have been rarely reported. Herein, we developed a new series of in situ forming antibacterial conductive degradable hydrogels using quaternized chitosan (QCS) grafted polyaniline with oxidized dextran as crosslinker. The chemical structures, morphologies, electrochemical property, conductivity, swelling ratio, rheological property, in vitro biodegradation and gelation time of hydrogels were characterized. Injectability was verified by in vivo subcutaneous injection on a Sprague Dawley rat. The antibacterial activity of the hydrogels was firstly evaluated employing antibacterial assay using Escherichia coli and Staphylococcus aureus in vitro. The hydrogels containing polyaniline showed enhanced antibacterial activity compared to QCS hydrogel, especially for hydrogels with 3 wt% polyaniline showing 95 kill% and 90kill% for E. coli and S. aureus, respectively. Compared with QCS hydrogel, the hydrogels with 3 wt% polyaniline still showed enhanced antibacterial activity for E. coli in vivo. The adipose-derived mesenchymal stem cells (ADMSCs) were used to evaluate the cytotoxicity of the hydrogels and hydrogels with polyaniline showed better cytocompatibility than QCS hydrogel. The electroactive hydrogels could significantly enhance the proliferation of C2C12 myoblasts compared to QCS hydrogel. This work opens the way to fabricate in situ forming antibacterial and electroactive degradable hydrogels as a new class of bioactive scaffolds for tissue regeneration applications. PMID:26272777

  3. Improving the moisturizing properties of collagen film by surface grafting of chondroitin sulfate for corneal tissue engineering.

    PubMed

    Liu, Yang; Lv, Huilin; Ren, Li; Xue, Guanhua; Wang, Yingjun

    2016-06-01

    Cornea disease is the second cause of blindness and keratoplasty is the most commonly performed option for visual rehabilitation of patients with corneal blindness. However, the clinical treatment has been drastically limited due to a severe shortage of high-quality donor corneas. Although collagen film with outstanding biocompatibility has promising application in corneal tissue engineering, the moisturizing properties of collagen-based materials must be further improved to satisfy the requirements of clinical applications. This paper describes a novel collagen-based film with high moisture capacity reinforced by surface grafting of chondroitin sulfate. The collagen-chondroitin sulfate (abbreviated as Col-CS) film was analyzed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy and its hydrophilic property, moisture retention, optical property, and mechanical performance had been tested. The moisture-retaining capacity is found to be improved with the introduction of chondroitin sulfate, and the Col-CS membrane performs better mechanical properties than the collagen film. Moreover, the modified film proves excellent biocompatibility for the proliferation of human corneal epithelial cells in vitro. This Col-CS film with good moisturizing properties can reduce the risk of xerophthalmia and is expected to increase the implant success rate in clinic patients with corneal defects. PMID:26948819

  4. Subepithelial connective tissue graft with and without the use of plasma rich in growth factors for treating root exposure

    PubMed Central

    Lafzi, Ardeshir; Shirmohammadi, Adileh; Behrozian, Ahmad; Kashefimehr, Atabak; Khashabi, Ehsan

    2012-01-01

    Purpose The aim of this study was to evaluate the clinical efficiency of the subepithelial connective tissue graft (SCTG) with and without plasma rich in growth factor (PRGF) in the treatment of gingival recessions. Methods Twenty bilateral buccal gingival Miller's Class I and II recessions were selected. Ten of the recessions were treated with SCTG and PRGF (test group). The rest ten of the recessions were treated with SCTG (control group). The clinical parameters including recession depth (RD), percentage of root coverage (RC), mucogingival junction (MGJ) position, clinical attachment level (CAL), and probing depth (PD) were measured at the baseline, and 1 and 3 months later. The data were analyzed using the Wilcoxon signed rank and Mann-Whitney U tests. Results After 3 months, both groups showed a significant improvement in all of the mentioned criteria except PD. Although the amount of improvement was better in the SCTG+PRGF group than the SCTG only group, this difference was not statistically significant. The mean RC was 70.85±12.57 in the test group and 75.83±24.68 in the control group. Conclusions Both SCTG+PRGF and SCTG only result in favorable clinical outcomes, but the added benefit of PRGF is not evident. PMID:23346462

  5. Photochemical tissue bonding

    DOEpatents

    Redmond, Robert W.; Kochevar, Irene E.

    2012-01-10

    Photochemical tissue bonding methods include the application of a photosensitizer to a tissue and/or tissue graft, followed by irradiation with electromagnetic energy to produce a tissue seal. The methods are useful for tissue adhesion, such as in wound closure, tissue grafting, skin grafting, musculoskeletal tissue repair, ligament or tendon repair and corneal repair.

  6. Surgical technique for the implantation of tissue engineered vascular grafts and subsequent in vivo monitoring.

    PubMed

    Koobatian, Maxwell T; Koenigsknecht, Carmon; Row, Sindhu; Andreadis, Stelios; Swartz, Daniel

    2015-01-01

    The development of Tissue Engineered Vessels (TEVs) is advanced by the ability to routinely and effectively implant TEVs (4-5 mm in diameter) into a large animal model. A step by-step protocol for inter-positional placement of the TEV and real-time digital assessment of the TEV and native carotid arteries is described here. In vivo monitoring is made possible by the implantation of flow probes, catheters and ultrasonic crystals (capable of recording dynamic diameter changes of implanted TEVs and native carotid arteries) at the time of surgery. Once implanted, researchers can calculate arterial blood flow patterns, invasive blood pressure and artery diameter yielding parameters such as pulse wave velocity, augmentation index, pulse pressures and compliance. Data acquisition is accomplished using a single computer program for analysis throughout the duration of the experiment. Such invaluable data provides insight into TEV matrix remodeling, its resemblance to native/sham controls and overall TEV performance in vivo. PMID:25867203

  7. Surgical Technique for the Implantation of Tissue Engineered Vascular Grafts and Subsequent In Vivo Monitoring

    PubMed Central

    Koobatian, Maxwell T.; Koenigsknecht, Carmon; Row, Sindhu; Andreadis, Stelios; Swartz, Daniel

    2015-01-01

    The development of Tissue Engineered Vessels (TEVs) is advanced by the ability to routinely and effectively implant TEVs (4-5 mm in diameter) into a large animal model. A step by-step protocol for inter-positional placement of the TEV and real-time digital assessment of the TEV and native carotid arteries is described here. In vivo monitoring is made possible by the implantation of flow probes, catheters and ultrasonic crystals (capable of recording dynamic diameter changes of implanted TEVs and native carotid arteries) at the time of surgery. Once implanted, researchers can calculate arterial blood flow patterns, invasive blood pressure and artery diameter yielding parameters such as pulse wave velocity, augmentation index, pulse pressures and compliance. Data acquisition is accomplished using a single computer program for analysis throughout the duration of the experiment. Such invaluable data provides insight into TEV matrix remodeling, its resemblance to native/sham controls and overall TEV performance in vivo. PMID:25867203

  8. Programmed death-1 pathway in host tissues ameliorates Th17/Th1-mediated experimental chronic graft-versus-host disease.

    PubMed

    Fujiwara, Hideaki; Maeda, Yoshinobu; Kobayashi, Koichiro; Nishimori, Hisakazu; Matsuoka, Ken-Ichi; Fujii, Nobuharu; Kondo, Eisei; Tanaka, Takehiro; Chen, Lieping; Azuma, Miyuki; Yagita, Hideo; Tanimoto, Mitsune

    2014-09-01

    Chronic graft-versus-host disease (GVHD) is a major cause of late death and morbidity after allogeneic hematopoietic cell transplantation, but its pathogenesis remains unclear. We investigated the role of the programmed death-1 (PD-1) pathway in chronic GVHD using a well-defined mouse model of B10.D2 (H-2(d)) donor to BALB/c (H-2(d)) recipients. PD-1 expression on allogeneic donor T cells was upregulated continuously in chronic GVHD development, whereas PD-L1 expression in host tissues was transiently upregulated and declined to basal levels in the late posttransplant period. Blockade of the PD-1 pathway by anti-PD-1, anti-PD-L1, or anti-PD-L2 mAbs exacerbated clinical and pathologic chronic GVHD. Chimeric mice revealed that PD-L1 expression in host tissues suppressed expansion of IL-17(+)IFN-γ(+) T cells, and that PD-L1 expression on hematopoietic cells plays a role in the development of regulatory T cells only during the early transplantation period but does not affect the severity of chronic GVHD. Administration of the synthetic retinoid Am80 overcame the IL-17(+)IFN-γ(+) T cell expansion caused by PD-L1 deficiency, resulting in reduced chronic GVHD damage in PD-L1(-/-) recipients. Stimulation of the PD-1 pathway also alleviated chronic GVHD. These results suggest that the PD-1 pathway contributes to the suppression of Th17/Th1-mediated chronic GVHD and may represent a new target for the prevention or treatment of chronic GVHD. PMID:25080485

  9. Neutrophil granulocytes recruited upon translocation of intestinal bacteria enhance graft-versus-host disease via tissue damage.

    PubMed

    Schwab, Lukas; Goroncy, Luise; Palaniyandi, Senthilnathan; Gautam, Sanjivan; Triantafyllopoulou, Antigoni; Mocsai, Attila; Reichardt, Wilfried; Karlsson, Fridrik J; Radhakrishnan, Sabarinath V; Hanke, Kathrin; Schmitt-Graeff, Annette; Freudenberg, Marina; von Loewenich, Friederike D; Wolf, Philipp; Leonhardt, Franziska; Baxan, Nicoleta; Pfeifer, Dietmar; Schmah, Oliver; Schönle, Anne; Martin, Stefan F; Mertelsmann, Roland; Duyster, Justus; Finke, Jürgen; Prinz, Marco; Henneke, Philipp; Häcker, Hans; Hildebrandt, Gerhard C; Häcker, Georg; Zeiser, Robert

    2014-06-01

    Acute graft-versus-host disease (GVHD) considerably limits wider usage of allogeneic hematopoietic cell transplantation (allo-HCT). Antigen-presenting cells and T cells are populations customarily associated with GVHD pathogenesis. Of note, neutrophils are the largest human white blood cell population. The cells cleave chemokines and produce reactive oxygen species, thereby promoting T cell activation. Therefore, during an allogeneic immune response, neutrophils could amplify tissue damage caused by conditioning regimens. We analyzed neutrophil infiltration of the mouse ileum after allo-HCT by in vivo myeloperoxidase imaging and found that infiltration levels were dependent on the local microbial flora and were not detectable under germ-free conditions. Physical or genetic depletion of neutrophils reduced GVHD-related mortality. The contribution of neutrophils to GVHD severity required reactive oxygen species (ROS) because selective Cybb (encoding cytochrome b-245, beta polypeptide, also known as NOX2) deficiency in neutrophils impairing ROS production led to lower levels of tissue damage, GVHD-related mortality and effector phenotype T cells. Enhanced survival of Bcl-xL transgenic neutrophils increased GVHD severity. In contrast, when we transferred neutrophils lacking Toll-like receptor-2 (TLR2), TLR3, TLR4, TLR7 and TLR9, which are normally less strongly activated by translocating bacteria, into wild-type C57BL/6 mice, GVHD severity was reduced. In humans, severity of intestinal GVHD strongly correlated with levels of neutrophils present in GVHD lesions. This study describes a new potential role for neutrophils in the pathogenesis of GVHD in both mice and humans. PMID:24836575

  10. Osteochondral Allograft Transplantation in the Knee.

    PubMed

    Zouzias, Ioannis C; Bugbee, William D

    2016-06-01

    The technique of osteochondral allograft (OCA) transplantation has been used to treat a wide spectrum of cartilage deficiencies in the knee. Its use has been supported by basic science and clinical studies that show it is a safe and effective treatment option. What sets fresh OCA transplantation apart from other cartilage procedures in the knee, is the ability to treat large defects with mature hyaline cartilage. Studies looking at transplantation of fresh OCAs in the general population have shown reliable pain relief and return to activities of daily living. Reports of cartilage injuries in athletes have risen over the years and more research is needed in evaluating the successfulness of OCA transplantation in the athletic population. PMID:27135291