OBJECTIVE: To build the trestle of tissue engineering for skin with the collagen. METHODS: The collagen was obtained from the baby cattle hide pretreated by Na2S and elastinase and Protease M, then the collagen was dissolved in 0.5 mol/L acetic acid solution. The collagen was treated with Protease N to minimize its immunogenicity. The resulting collagen could be used to build the trestle of tissue engineering for skin because of good biocompatibility. The collagen molecular weight and structure were analyzed by SDS-PAGE. The bioactivity of trestle was tested in the experiment of the mice wound healing and the cell implantation. RESULTS: The SDS-PAGE result of the collagen treated by Protease M showed the typical spectrum of type I collagen. The built trestle was a collagen sponge matrix in which micropore size was 50-200 microns. It could accelerate wound healing and the implanted fibroblasts could proliferate well. CONCLUSION: The collagen treated by Protease N can get good biocompatibilily and is suitable for building the trestles of tissue engineering for skin with good bioactivity.
Objective To review research progress of corneal tissueengineering.Methods The recent articles on corneal tissue engineering focus on source and selection of corneal cells, the effects of growth factors on culture of corneal cells in vitro. The preparation and selection of three-dimensional biomaterial scaffolds and their b and weak points were discussed. Results The corneal tissue engineering cells come from normal human corneal cells. The embryo corneal cell was excellent. Several kinds of growth factors play important roles in culture, growth and proliferation of corneal cell, and incroporated into matrix.Growth factors including basic fibroblast growth factor, keratinocyte growth factor, transforming growth factor β1 and epidermal growth factor was favor to corneal cell. Collagen, chitosan and glycosaninoglycans were chosen as biomaterial scaffolds. Conclusion Human tissue engineering cornea can be reconstructed and transplanted. It has good tissue compatibility and can be used as human corneal equivalents.
ObjectiveTo analyze the progress in biological tissue engineering scaffold materials and the clinical application, as well as product development status. MethodsBased on extensive investigation in the status of research and application of biological tissue engineering scaffold materials, a comprehensive analysis was made. Meanwhile, a detailed analysis of research and product development was presented. ResultsConsiderable progress has been achieved in research, products transformation, clinical application, and supervision of biological scaffold for tissue engineering. New directions, new technology, and new products are constantly emerging. With the continuous progress of science and technology and continuous improvement of life sciences theory, the new direction and new focus still need to be continuously adjusted in order to meet the clinical needs. ConclusionFrom the aspect of industrial transformation feasibility, acellular scaffolds and extracellular matrix are the most promising new growth of both research and product development in this field.
ObjectiveTo investigate the feasibility of lung tissue flap repairing esophagus defect with an inner chitosan tube stentin in order to complete repairing and reconsruction of the esophagus defect.MethodsFifteen Japanese white rabbits were randomly divided into two groups， experiment group(n=10): esophagus defect was repaired with lung tissue flap having inner chitosan tube stent; control group(n=5): esophagus defect was repaired with lung tissue flap without inner chitosan tube stent; and then the gross and histological apearance in both groups were observed at 2, 4,8 weeks after operation, barium sulphate X-ray screen were observed at 10 weeks after operation.ResultsSix rabbits survived for over two weeks in experiment group, lung tissue flap healed with esophageal defect, squamous metaplasia were found on the surface of lung tissue flap in experiment group. At 10 weeks after operation, barium sulphate examination found that barium was fluent through the esophageal and no narrow or reversed peristalsis, the peristalsis was good in experiment group.Four rabbits survived for two weeks and the lung tissue flap healed with esophageal defect, fibrous tissue hyperplasy on the surface of the lung tissue flap in control group. At 10 weeks after operation, barium sulphate examination found that barium was fluent through the esophageal and slight narrow or reversed peristalsis, the peristalsis was not good in control group, otherwise.ConclusionIt is a feasible method to repair the esophageal defect with lung tissue flap with the inner chitosan stent.
Objective To evaluate the feasibility of X-ray guided access to the extrahepatic segment of the main portal vein (PV) to create a transjugular extrahepatic portacaval shunt (TEPS). Methods 5F pigtail catheter was inserted into the main PV as target catheter by percutaneous transhepatic path under ultrasound guidance. The RUPS-100 puncture system was inserted into the inferior vena cava (IVC) by transjugular path under ultrasound guidance. Fluency covered stent was deployed to create the extrahepatic portacaval shunt after puncturing the target catheter from the IVC under the X-ray guidance, then shunt venography was performed. Enhanced CT of the abdomen helped identify and quantify the patency of the shunt and the presence of hemoperitoneum. Results The extrahepatic portacaval shunts were created successfully by only 1 puncture in 6 pigs. No extravasation was observed in shunt venography. One pig died of anesthesia on the day of operation. The extrahepatic portacaval shunts were failed in 2 pigs 3 days after the operation (one was occluded and the other one was narrowed by 80%). The extrahepatic portacaval shunts were occluded 2 weeks after the operation in the remaining 3 pigs. The shunts were out of the liver and no hemoperitoneum was identified at necropsy in the 6 pigs. Conclusion TEPS is technically safe and feasible under the X-ray guidance.
Objective To explore a method of loading exosomes onto absorbable stents. MethodsBy building a stent-(3-aminopropyl) triethoxysilane-1, 2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol) 5000]-exosomes connection, the exosomes were loaded onto absorbable stents to obtained the exosome-eluting absorbable stents. The surface conditions of the stents and absorption of exosomes were observed by scanning electron microscope and identified through the time-of-flight mass spectrometry; the roughness of the stents’ surfaces was observed by atomic force microscope; the appearances and sizes of the stents were observed by stereomicroscope; and the radial force was tested by tensile test machine. The absorbable stents were used as control. Results The scanning electron microscope observation showed that the exosome-eluting absorbable stents had some small irregular cracks on the surface where many exosomes could be seen. The atomic force microscopy observation showed that within the range of 5 μm2, the surface roughness of the absorbable stents was ±20 nm, while the surface roughness of the exosome-eluting absorbable stents was ±70 nm. In the results of time-of-flight mass spectrometry, both the exosome-eluting absorbable stents and exosomes had a peak at the mass charge ratio of 81 (m/z 81), while the absorbable stents did not have this peak. The peak of exosome-eluting absorbable stents at m/z 73 showed a significant decrease compared to the absorbable stents. The stereomicroscope observation showed that the sizes of exosome-eluting absorbable stents met standards and the surfaces had no cracks, burrs, or depressions. The radial force results of the exosome-eluting absorbable stents met the strength standards of the original absorbable stent. Conclusion By applying the chemical connection method, the exosomes successfully loaded onto the absorbable stents. And the sizes and radial forces of this exosome-eluting absorbable stents meet the standards of the original absorbable stents.
OBJECTIVE: To study the feasibility of calcium polyphosphate fiber (CPPF) as the scaffold material of tendon tissue engineering. METHODS: CPPF (15 microns in diameter) were woven to form pigtail of 3 mm x 2 mm transverse area; and the tensile strength, porous ratio and permeability ratio were evaluated in vitro. Tendon cells (5 x 10(4)/ml) derived from phalangeal flexor tendon of SD rats were co-culture with CPPF scaffold or CPPF scaffold resurfaced with collagen type-I within 1 week. The co-cultured specimens were examined under optical and electric scanning microscope. RESULTS: The tensile strength of CPPF scaffolds was (122.80 +/- 17.34) N; permeability ratio was 61.56% +/- 14.57%; and porous ratio was 50.29% +/- 8.16%. CPPF had no obvious adhesive interaction with tendon cells, while CPPF of surface modified with collagen type-I showed good adhesive interaction with tendon cells. CONCLUSION: The above results show that CPPF has some good physical characteristics as scaffold of tendon tissue engineering, but its surface should be modified with organic substance or even bioactive factors.
Objective To establish a scaffold model from heterogeneoussmall blood vessels. Methods Caudal arteries from 34 Wistar rats( average length 12.08±1.69 cm) were made into acellular blood vessel scaffolds. Some scaffoldswere observed by electron microscope, and others were transplanted to the cut ends of ear central arteries of male Japanese big ear white rabbits. Results Average external diameter was 0.74±0.08 mm in proximal, and 0.55±0.08 mm in distal end of rat caudal arteries. The small blood vessel scaffolds had shin wall whichwas white and soft, composed of fibrous tissues without cells. On the intima surface the fibrous tissues were arrayed densely in a grid-like pattern. After transplantation, the blood flow was reserved, and kept flowing freely in 24 hours. The pulsation of the transplanted artery was accessible and no blood leakage wasfound.Conclusion The natural scaffolds are composed of fibrous tissues, and can sustain the artery pulse pressure for 24 hours. It is better to suture the blood vessels by sleeve anastomosis.
Forty cases of intertrochanteric fractures of femur were treated with percutaneous nonmetallic external fixator. The patients were followed up for 6 months to 3 years, and the fractures were all united without coxa vara or shirtening deformities. There was no mortality in this series. This method had the advantages ofbeing simple, save time and effort, less traumatic and early ambulation. The design of the apparatus tallied with the biomechanics of the neck and shaft of the femur.