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.
Objective To comment on the recent advances of production and application of the bio-derived scaffold in the tissue engineered peripheral nerve. Methods The recent articles were systematically analyzed, and then the production methods of the bio-derived scaffold and its application to the tissue engineered peripheral nerve were evaluated and prospected. Results B iological tissues were processed by some methods to produce the bio-derived materials. These mat erials could maintain the structure and components of the tissues. Moreover, the immunogenicity of these materials was reduced. Conclusion Application of the bio-derived materials is a trend in the fabricating scaffold of the tissue en gineered peripheral nerve.
Objective To review the recent progress of the researches in the field of cartilage tissue engineering, and to discuss the challenges in construction of tissue engineered cartilage. Methods Literature related with cartilage tissue engineering was reviewed and analyzed. Results Some techniques have been appl ied in cl inical. As far as the seeding cells, induced pluripotent stem cells have attracted much more attention. Current strategies of scaffold designing are trying to imitate both component and structure of natural extracellular matrix. Cartilage regeneration through the autologous cell homing technique el iminate the transplantation of exotic cells and has become the hot topic. Conclusion Successful treatment of the damaged cartilage using tissue engineering method will depend on the advances of stem cell technology development, biomimetic scaffolds fabrication and proper appl ication of growth factors.
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.
Objective To analyze the etiologies, surgical treatment and outcomes of retrograde type A aortic dissection (RTAD) after thoracic endovascular aortic repair (TEVAR) for Stanford type B aortic dissection. Methods The clinical data of patients with RTAD after TEVAR for Stanford type B aortic dissection receiving operations in Changhai Hospital from March 2014 to August 2018 were analyzed. All patients were followed-up by clinic interview or telephone. Results A total of 16 patients were enrolled, including 13 males and 3 females with a mean age of 49.1±12.2 years. The main symptoms of RTAD were chest pain in 12 patients, headache in 1 patient, conscious disturbance in 1 patient, and asymptomatic in 2 patients. All the 16 patients received total arch replacement with the frozen elephant trunk technique. Bentall procedure was used in 2 patients, aortic root plasticity in 10 patients and aortic valve replacement in 1 patient. The primary tear in 10 patients was located in the area which were anchored by bare mental stent, and in the other 6 patients it was located in the anterior part of ascending aorta. The mean cardiopulmonary bypass time was 152.2±29.4 min, aortic cross-clamping time was 93.6±27.8 min and selective cerebral perfusion time was 29.8±8.3 min. There was no death in hospital or within postoperative 30 days. The follow-up period was 32-85 (57.4±18.3) months. No death occurred during the follow-up period. One patient underwent TEVAR again 3 years after this operation and had an uneventful survival. Conclusion Total arch replacement with the frozen elephant trunk technique is a suitable strategy for the management of RTAD after TEVAR for Stanford type B aortic dissection.
The interventional therapy of vascular stent implantation is a popular treatment method for cardiovascular stenosis and blockage. However, traditional stent manufacturing methods such as laser cutting are complex and cannot easily manufacture complex structures such as bifurcated stents, while three-dimensional (3D) printing technology provides a new method for manufacturing stents with complex structure and personalized designs. In this paper, a cardiovascular stent was designed, and printed using selective laser melting technology and 316L stainless steel powder of 0−10 µm size. Electrolytic polishing was performed to improve the surface quality of the printed vascular stent, and the expansion behavior of the polished stent was assessed by balloon inflation. The results showed that the newly designed cardiovascular stent could be manufactured by 3D printing technology. Electrolytic polishing removed the attached powder and reduced the surface roughness Ra from 1.36 µm to 0.82 µm. The axial shortening rate of the polished bracket was 4.23% when the outside diameter was expanded from 2.42 mm to 3.63 mm under the pressure of the balloon, and the radial rebound rate was 2.48% after unloading. The radial force of polished stent was 8.32 N. The 3D printed vascular stent can remove the surface powder through electrolytic polishing to improve the surface quality, and show good dilatation performance and radial support performance, which provides a reference for the practical application of 3D printed vascular stent.
Objective To review the recent advances in the application of graphene oxide (GO) for bone tissue engineering. Methods The latest literature at home and abroad on the GO used in the bone regeneration and repair was reviewed, including general properties of GO, degradation performance, biocompatibility, and application in bone tissue engineering. Results GO has an abundance of oxygen-containing functionalities, high surface area, and good biocompatibility. In addition, it can promote stem cell adhesion, proliferation, and differentiation. Moreover, GO has many advantages in the construction of new composite scaffolds and improvement of the performance of traditional scaffolds. Conclusion GO has been a hot topic in the field of bone tissue engineering due to its excellent physical and chemical properties. And many problems still need to be solved.
Aiming at the problem of scaffold degradation in bone tissue engineering, we studied the feasibility that controlls bone defect repair effect with the inhomogeneous structure of scaffold. The prediction model of bone defect repair which contains governing equations for bone formation and scaffold degradation was constructed on the basis of analyzing the process and main influence factors of bone repair in bone tissue engineering. The process of bone defect repair and bone structure after repairing can be predicted by combining the model with finite element method (FEM). Bone defect repair effects with homogenous and inhomogeneous scaffold were simulated respectively by using the above method. The simulation results illustrated that repair effect could be impacted by scaffold structure obviously and it can also be controlled via the inhomogeneous structure of scaffold with some feasibility.