Publications (46) View all
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Article: The evaluation of canine small intestinal submucosal xenograft and polypropylene mesh as bioscaffolds on an abdominal full-thickness resection model in growing rats.
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ABSTRACT: We evaluated the biological scaffold properties of canine small intestinal submucosa (SIS) in comparison with those of polypropylene mesh in growing rats with full-thickness abdominal defects. SIS is used to repair musculoskeletal tissue and can promote cell migration and support tissue regeneration. Polypropylene mesh is a non-resorbable synthetic material that can endure mechanical tension and is both inexpensive and widely used. Canine SIS was obtained from donor German Shepherds, and its porous collagen fiber structure was identified using scanning electron microscopy. A 2.50 cm2 portion of canine SIS (SIS group) or mesh (mesh group) was implanted in Sprague Dawley rats. At 1, 2, 4, 12, and 24 weeks after surgery, the implants were assessed histopathologically and tested for tensile load. One month after surgery, CD68+ macrophage levels in the SIS group were upregulated, but the levels of CD8+ T cells declined more rapidly than that in the mesh group. In the SIS group, there were few adhesions and well-developed autologous abdominal muscle infiltration into the SIS collagen fibers. In the tensile load test, there was no significant difference between SIS and mesh at 24 weeks. Canine SIS may be a good replacement for biological scaffolds in small-animal practice.Journal of veterinary science (Suwŏn-si, Korea) 04/2013; · 0.89 Impact Factor -
Article: Local BMP-7 release from a PLGA scaffolding-matrix for the repair of osteochondral defects in rabbits.
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ABSTRACT: The use of tissue engineering to repair large osteochondral defects has been impeded by the limited regenerative capacity of cartilage. Herein, we describe the local release of bone morphogenetic protein 7 (BMP-7) to stimulate the bone marrow-derived progenitors to repair osteochondral defects. BMP-7-releasing poly(d,l-lactide-co-glycolide) (PLGA) matrix was specially designed to retain the dual-function of local BMP-7 release and progenitor-scaffolding with its defect-fitting architecture. To optimize the release kinetics during the repair period, BMP-7/PLGA film was cast on the surface of a cylindrical PLGA matrix. The matrix demonstrated a release profile of BMP-7 in a sustained manner over 28days, maintaining its biological activity. The cylindrical PLGA matrices loaded with BMP-7 were implanted into the osteochondral defects (2mm in diameter, 3mm in depth) in rabbit knees. Histological observations revealed that neo-cartilage generation was completed in a well-integrated morphology with its surrounding normal cartilage and subchondral bone at 12weeks post-implantation. Partial degradation of the PLGA matrix during the repair period guided neo-cartilage formation, which verified the effective scaffolding function of the matrix. Regenerated cartilage in BMP-7-treated defects stained positive for type II collagen and glycosaminoglycan (GAG). Adjacent BMP-7-untreated defects were also repaired with cartilage regeneration, suggesting the effect of local BMP-7 release in the synovial fluid. The BMP-7-unloaded PLGA matrix demonstrated guided cartilage regeneration to a certain extent, whereas the adjacent defects without the matrix revealed only fibrous tissue infiltration. These results indicated that a strategy employing the combined functions of local BMP-7 release and the cell scaffolding of a PLGA matrix might be a potential modality for osteochondral repair.Journal of Controlled Release 08/2012; 162(3):485-91. · 5.73 Impact Factor -
Article: Platelet-rich plasma loaded in situ-formed hydrogel enhances hyaline cartilage regeneration by CB1 upregulation.
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ABSTRACT: The efficacy of three-dimensional (3D) culture on the proliferation and maturation of chondrocytes seeded into a hydrogel scaffold was assessed. Three types of hydrogel were prepared for the 3D culture of primary isolated chondrocytes. Chondrocyte proliferation was assessed using a live/dead viability/cytotoxicity assay and semiquantitative RT-PCR after 3D culture in hydrogel. Cylindrical defects in the center of rat xyphoids were used for the implantation of platelet-rich plasma (PRP)/hydrogel composites. Rats were killed at day 7 postoperatively and evaluated histochemically and immunohistologically. Xyphoid chondrocytes proliferated well with time in hydrogels. In the PRP-containing hydrogels, xyphoid defects displayed early formation of chondroid matrix with massive peripheral infiltration of spindle cells. These results were consistent with Safranin-O staining for proteoglycans and immunohistochemistry for type II collagen. Gene expression analyses in vitro revealed aggrecan, type II collagen, and ChM-1 and CB1 upregulation by PRP/hydrogel. PRP/hydrogel provided a suitable environment for hyaline cartilaginous regeneration, leading to anti-inflammation by significant increase of CB1 and inhibiting vascular ingrowth via considerable upregulation of ChM-1. The results provide a valuable reference for the clinical application of hydrogel scaffolds for hyaline cartilage regeneration, as well as the use of autologous PRP to improve cellular proliferation and maturation of xyphoid repair. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 100A:3099-3107, 2012.Journal of Biomedical Materials Research Part A 06/2012; 100(11):3099-107. · 2.63 Impact Factor -
Article: Anterior cruciate ligament reconstruction in a rabbit model using canine small intestinal submucosa and autologous platelet-rich plasma.
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ABSTRACT: The bone-ligament interface is the main point of failure after anterior cruciate ligament reconstruction. Synthetic ligament materials have problems such as a greater failure rate of the bone-ligament insertion than autografts. Small intestinal submucosa (SIS) is a biologic scaffold that has been used to repair musculoskeletal tissue and has been shown to promote cell migration and enhance collagen fiber regeneration. Autologous platelet-rich plasma (PRP) has also been investigated as a potential promoter of tendon healing. We investigated SIS and PRP as biomaterials that might strengthen the bone-tunnel interface and improve tendon structure formation. Anterior cruciate ligament grafts were formed of braid-twist canine SIS. These canine SIS ligament grafts were used for anterior cruciate ligament reconstruction in 20 New Zealand white rabbits. The rabbits were divided into 2 treatment groups. In 1 group (SIS group; n = 10), we only implanted the canine SIS grafts. In the second group (PRP group; n = 10), we applied autologous PRP to the surgical area after implantation of canine SIS grafts. We determined the cytokine level of the autologous PRP using a transforming growth factor-β1 enzyme-linked immunosorbent assay kit. At 1 and 4 wk after surgery, magnetic resonance imaging was performed to evaluate the grafts. The femur-graft-tibia complex was assessed histologically and biomechanically at 8 wk after surgery. At 1 wk after surgery, the magnetic resonance imaging scans of the PRP group showed high signal-intensity lesions. In biomechanical tests, the SIS group had a significantly greater maximum load, maximum stress, and ultimate load and strain than the PRP group. The histologic findings of the PRP group revealed a greater cellular response, fibrotic tissue regeneration around the graft, broad chondrocyte cell infiltration, and collagen fibers that were loosely attached to the bone. The PRP group had significantly lower tension load values than the SIS group, and there was greater cellular response in a broad area around the grafts of the rabbits in the PRP group compared with those in the SIS group. The early inflammatory responses around the canine SIS grafts in the PRP group and the altered cytokine or growth factor concentration in the intra-articular capsule of the rabbits in PRP group might explain their relatively low tensile strength results.Journal of Surgical Research 03/2012; 178(1):206-15. · 2.25 Impact Factor -
Article: Time-sequential modulation in expression of growth factors from platelet-rich plasma (PRP) on the chondrocyte cultures.
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ABSTRACT: Platelets are involved in hemostasis, wound healing, and tumor growth. Autologous blood products are commonly used to facilitate healing in a variety of clinical surgery applications. Recently, it was shown that platelet-rich plasma (PRP) has more specific growth factors that participate in the healing process. This study investigated the expression of PRP growth factors and evaluated their potential role in the cartilage regeneration using primary isolated chondrocytes. PRP obtained from New Zealand White rabbit by low speed centrifugation. Extracted PRPs contained 6-10 × 10(6) platelet/μl and concentration of platelets was slightly variable. Primary isolated chondrocytes from the same rabbits were cultured and treated with 0.1-20% PRP. The cells were collected and examined by reverse transcription-polymerase chain reaction and cytochemical staining. The expression of sex determining region Y-box 9, transforming growth factor-beta, vascular endothelial growth factor, and chondromdulin-I was increased in chondrocyte cultures with 10% PRP by time-dependent manner. To maintain the integrity of the cartilage, the proteoglycan contents were also up-regulated from the mRNA of aggrecan and positive Safranin-O staining in PRP concentration- and time-dependent manner. PRP provides crucial growth factors related to chondrocyte proliferation and differentiation through time-sequential modulation. Controlled in vivo trials for cartilage regeneration are needed.Molecular and Cellular Biochemistry 09/2011; 361(1-2):9-17. · 2.06 Impact Factor
