Bone Regeneration in the Extraction Socket Filled with Atelocollagen: Histological and Radiographic Study in Beagle Dogs

PURPOSE: Alveolar bone develops with tooth eruption and is absorbed following tooth extraction. Various ridge preservation techniques have sought to prevent ridge atrophy, with no superior technique evident. Collagen has a long history as a biocompatible material. Its usefulness and safety have been amply verified. The related compound, atelocollagen, is also safe and displays reduced antigenicity since telopeptides are not present. MATERIALS AND METHODS: The current study evaluated whether the Rapiderm® atelocollagen plug (Dalim Tissen, Seoul, Korea) improves tissue healing of extraction sockets and assessed the sequential pattern of bone regeneration using histology and microcomputed tomography in six beagle dogs. To assess the change of extraction socket, hard tissues were examined 2, 4, 6, and 8 weeks after tooth extraction. RESULT: The experimental groups showed better bone fill with slow remodeling process compared to the control groups although there was no statistical difference between groups. CONCLUSION: The atelocollagen seems to have a tendency to slow bone remodeling in the early phase of healing period and maintain remodeling capacity until late phase of remodeling. Also, use of atelocollagen increased the bone-to-tissue ratio compared to healing of untreated extraction socket.

Tissue Engineered Intervertebral Disc by Atelocollagen Scaffolds and Growth Factors / 대한척추외과학회지

STUDY DESIGN: In vitro experimental study. OBJECTIVES: To examine the cellular proliferation, synthetic activity and phenotypical expression of intervertebral disc (IVD) cells seeded on types I and II atelocollagen scaffolds, with the stimulation of TGF-beta1 and BMP-2. SUMMARY OF LITERATURE REVIEW: Recently, tissue engineering is regarded as a new experimental technique for the biological treatment of degenerative IVD diseases, and has been highlighted as a promising technique for the regeneration of tissues and organs in the human body. Research on cell transplantation in artificial scaffolds has provided that the conditions for tissue engineering have to be equilibrated, including the cell viability and proliferation, maintenance of characteristic phenotype, suitable scaffolds in organisms and biologically stimulated growth factor. MATERIAL AND METHOD: Lumbar IVD cells were harvested from 10 New Zealand white rabbits, with the nucleus pulposus cells isolated by sequential enzymatic digestion. Each of 1% types I and II atelocollagen dispersions were poured into a 96-well plate (diameter 5 mm), frozen at -70 degrees C, and then lyophilized at -50 degrees C. Fabricated porous collagen matrices were made using the cross-linking method. Cell suspensions were imbibed by surface tension into a scaffold consisting of atelocollagen. The cell cultured scaffolds were then treated with TGF-beta1 (10 ng/ml) or BMP-2 (100 ng/ml) or both. After 1 and 2 week culture periods, the DNA synthesis was measured by [3H] thymidine incorporation, and newly synthesized proteoglycan by incorporation of [35S] sulphate. Reverse transcription-polymerase chain reactions for the mRNA expressions of type I and II collagen, aggrecan and osteocalcin were performed. The inner morphology of the scaffolds was determined by scanning electron microscopy (SEM). RESULTS: The IVD cultures in collagen type II with TGF-beta1 demonstrated an increase in proteoglycan synthesis and up regulation of aggrecan and types I and II collagen mRNA expressions compared to the control. IVD cultures in the type I atelocollagen scaffold with growth factors exhibited an increase in DNA synthesis and up regulation of the type II atelocollagen mRNA expression. With all combinations of growth factor, the IVD cultures in types I and II atelocollagen scaffolds showed no up regulation of the osteocalcin mRNA expression. Furthermore, there was no synergistic effect of TGF-beta1 and BMP-2 in the matrix synthesis or for the mRNA expression of the matrix components. CONCLUSIONS: Nucleus pulposus cells from rabbit were viable in atelocollagen types I and II atelocollagen scaffolds. The type I atelocollagen scaffold was suitable for cell proliferation, but the type II atelocollagen scaffold was more suitable for extracellular matrix synthesis. The IVD cells in both scaffolds were biologically responsive to growth factors. Taken together, nucleus pulposus cells in atelocollagen scaffolds, with anabolic growth factors, provide a mechanism for tissue engineering of IVD cells.

Tissue Engineered Intervertebral Disc by Atelocollagen Scaffolds and Growth Factors / 대한척추외과학회지

STUDY DESIGN: In vitro experimental study. OBJECTIVES: To examine the cellular proliferation, synthetic activity and phenotypical expression of intervertebral disc (IVD) cells seeded on types I and II atelocollagen scaffolds, with the stimulation of TGF-beta1 and BMP-2. SUMMARY OF LITERATURE REVIEW: Recently, tissue engineering is regarded as a new experimental technique for the biological treatment of degenerative IVD diseases, and has been highlighted as a promising technique for the regeneration of tissues and organs in the human body. Research on cell transplantation in artificial scaffolds has provided that the conditions for tissue engineering have to be equilibrated, including the cell viability and proliferation, maintenance of characteristic phenotype, suitable scaffolds in organisms and biologically stimulated growth factor. MATERIAL AND METHOD: Lumbar IVD cells were harvested from 10 New Zealand white rabbits, with the nucleus pulposus cells isolated by sequential enzymatic digestion. Each of 1% types I and II atelocollagen dispersions were poured into a 96-well plate (diameter 5 mm), frozen at -70 degrees C, and then lyophilized at -50 degrees C. Fabricated porous collagen matrices were made using the cross-linking method. Cell suspensions were imbibed by surface tension into a scaffold consisting of atelocollagen. The cell cultured scaffolds were then treated with TGF-beta1 (10 ng/ml) or BMP-2 (100 ng/ml) or both. After 1 and 2 week culture periods, the DNA synthesis was measured by [3H] thymidine incorporation, and newly synthesized proteoglycan by incorporation of [35S] sulphate. Reverse transcription-polymerase chain reactions for the mRNA expressions of type I and II collagen, aggrecan and osteocalcin were performed. The inner morphology of the scaffolds was determined by scanning electron microscopy (SEM). RESULTS: The IVD cultures in collagen type II with TGF-beta1 demonstrated an increase in proteoglycan synthesis and up regulation of aggrecan and types I and II collagen mRNA expressions compared to the control. IVD cultures in the type I atelocollagen scaffold with growth factors exhibited an increase in DNA synthesis and up regulation of the type II atelocollagen mRNA expression. With all combinations of growth factor, the IVD cultures in types I and II atelocollagen scaffolds showed no up regulation of the osteocalcin mRNA expression. Furthermore, there was no synergistic effect of TGF-beta1 and BMP-2 in the matrix synthesis or for the mRNA expression of the matrix components. CONCLUSIONS: Nucleus pulposus cells from rabbit were viable in atelocollagen types I and II atelocollagen scaffolds. The type I atelocollagen scaffold was suitable for cell proliferation, but the type II atelocollagen scaffold was more suitable for extracellular matrix synthesis. The IVD cells in both scaffolds were biologically responsive to growth factors. Taken together, nucleus pulposus cells in atelocollagen scaffolds, with anabolic growth factors, provide a mechanism for tissue engineering of IVD cells.

Diffuse Pulmonary Alveolar Hemorrhage and Interstitial Pneumonitis after Subcutaneous Injection of Atelocollagen for Cosmetic Purpose: Two Case Reports / 결핵

Atelocollagen have been used recently in skin and other soft tissue defect regions more than silicone fluid because of the low incidence of an immune reaction and complications. Several cases of acute pneumonitis after a subcutaneous injection of silicone have been reported. The symptoms were dyspnea, fever, chest pain and hemoptysis. Previous reports have explained the pathophysiology of acute pneumonitis to a pulmonary microembolism and cellular inflammation. We experienced two cases of an acute interstitial pneumonitis and pulmonary hemorrhage after a subcutaneous injection of atelocollagen. They were all healthy young women and complained of dyspnea, fever and blood tinged sputum. The chest radiography and computerized tomography showed a bilateral ground glass opacity in both lung fields. One case recovered completely with conservative treatment but the clinical course of the other case was aggravated to the degree that invasive positive pressure ventilation therapy was required. We report a rare case of a diffuse pulmonary alveolar hemorrhage and an interstitial pneumonitis after the subcutaneous injection of atelocollagen for cosmetic purposes.

Behavior of Fibroblasts on a Porous Hyaluronic Acid Incorporated Collagen Matrix

A hyaluronic acid (HA) incorporated porous collagen matrix was fabricated at -70 degree C by lyophilization. The HA incorporated collagen matrix showed increased pore size in comparison with collagen matrix. Biodegradability and mechanical properties of matrices were controllable by varying the ultraviolet (UV) irradiation time for cross-linking collagen molecules. Addition of HA to collagen matrix did not effect ultimate tensile stress after UV irradiation. HA incorporated collagen matrices demonstrated a higher resistance against the collagenase degradation than collagen matrix. In an in vitro investigation of cellular behavior using dermal fibroblasts on the porous matrix, HA incorporated collagen matrix induced increased dermal fibroblast migration and proliferation in comparison with collagen matrix. These results suggest that the HA incorporated collagen porous matrix assumes to enhance dermal fibroblast adaptation and regenerative potential.

A bone replaceable artificial bone substitute: morphological and physiochemical characterizations

A composite material consisting of carbonate apatite (CAp) and type I atelocollagen (AtCol) (88/12 in wt/wt%) was designed for use as an artificial bone substitute. CAp was synthesized at 58 degrees C by a solution-precipitation method and then heated at either 980 degrees C or 1,200 degrees C. In this study, type I AtCol was purified from bovine tail skins. A CAp-AtCol mixture was prepared by centirfugation and condensed into composite rods or disks. The scanning electron-microscopic (SEM) characterization indicated that the CAp synthesized at 58 degrees C displayed a crystallinity similar to that of natural bone and had a high porosity (mean pore size: about 3-10 microns in diameter). SEM also revealed that the CAp heated at 980 degrees C was more porous than that sintered at 1,200 degrees C, and the 1,200 degrees C-heated particles were more uniformly encapsulated by the AtCol fibers than the 980 degrees C-heated ones. A Fourier transformed-infrared spectroscopic analysis showed that the bands characteristic of carbonate ions were clearly observed in the 58 degrees C-synthesized CAp. To enhance the intramolecular cross-linking between the collagen molecules, CAp-AtCol composites were irradiated by ultraviolet (UV) ray (wave length 254 nm) for 4 hours or vacuum-dried at 150 degrees C for 2 hours. Compared to the non cross-linked composites, the UV-irradiated or dehydrothermally cross-linked composites showed significantly (p < 0.05) low collagen degradation and swelling ratio. Preliminary mechanical data demonstrated that the compressive strengths of the CAp-AtCol composites were higher than the values reported for bone.

Reconstruction of rabbit knee joint cartilage defect using tissues engineering method / 中华显微外科杂志

Objective To estimate curative effect of reconstruction of rabbit knee joint cartilage defect with the homogeneitic tissue engineered cartilages.Methods The chondrocytes were isolated and collected from articular cartilages of eight New Zealand white rabbits.The tissue engineered cartilages after culturing chondrocytes and atelocollogen for two days.Cartilage defects were created in both keen joint of twenty-six rab- bits.Complexes of chodrocytes and atelocollagen was grafted into the defect of left knee joint at once as experi- mental group,and no implantation were served as control.General and histological examination were respec- tively performed in both group at four weeks and eight weeks after surgery.Results After implantation,the defects were filled with cartilaginous tissue in experiment group,while there were only tissue in control group. Histologically,defective areas were filled with chondrocytes in experiment group,but only fibroblast in control group.Conclusion The implantation of the tissue engineered cartilages contenting with chondrocytes and atelocollogen can effectively improve reconstruction of rabbit knee joint.

BIOCOMPATIBILITY OF ATELOCOLLAGEN SCAFFOLD IN THE THREE DIMENSIONAL CULTURED RAT CARDIAC MYOCYTE / 解剖学报

Objective To investigate the biocompatibility between the atelocollagen scaffold and 3D-cultured myocardial cells,and to find out the condition and an optimal biomaterial scaffold that can be applied to 3D-culture myocardial tissue. Methods The primary cultured myocardial cells were purified and then inoculated into the atelocollagen scaffold.The cells in the atelocollagen scaffold were observed by light microscope,scanning electron microscope(SEM) and transmission electron microscope(TEM) at different times(8d,16d,20d). Results On the first day,cardiac cells pulsating together with the atelocollagen scaffold could be detected under the microscope,which were pulsating complex.A plenty of cells in the atelocollagen mesh were observed under the light microscope,and the cells coalesced with the scaffold.The cells were compacted to the scaffold and coalesced with it at three stages under TEM.Those cells were sticked to the atelocollagen scaffold and expanded sufficiently under SEM.On the atelocollagen scaffold surface,these cells coalesced with lamellar.Conclusion The biocompatibility of the atelocollagen scaffold is better for cultured cardiac myocyte.It can be used as a natural material for 3D-cultured cells,and is suitable for 3D-cultured cardiac cells and cardiac tissues.