OBJECTIVE To investigate the methods to fabricate repair materials of tissue engineered peripheral nerve with bioactivity of Schwann cells (SC). METHODS 1. The materials were made by dry-wet spinning process to fabricate PLA hollow fiber canal with external diameter of 2.3 mm, internal diameter of 1.9 mm, thickness of 0.4 mm, pore size of 20 to 40 microns, pore ratio of 70% and non-spinning fiber net with pore size of 100 to 200 microns, pore ratio of 85%. 2. SC were implanted into excellular matrix (ECM) gel to observe the growth of SC. 3. SC/ECM complex were implanted into non-spinning PLA fiber net to observe the growth of SC. 4. SC, SC/ECM and SC/ECM/PLA were implanted into PLA hollow fiber canal to bridge 10 mm defect of rat sciatic nerve. RESULTS 1. SC were recovered bipolar shape at 1 day after implantation, and could be survived 14 days in ECM gel. 2. After SC/ECM complex was implanted into PLA net, most of SC were retained in the pore of PLA net with the formation of ECM gel. SC could be adhered and grown on PLA fiber. 3. Most of SC in ECM gel could be survived to 21 days after transplantation. Survival cell numbers of SC/ECM and SC/ECM/PLA groups were obviously higher than SC suspension group. CONCLUSION Non-spinning PLA porous biodegradable materials with ECM is benefit for SC to be adhered and grown.
Objective To explore the advance in physical materials,chemical matrix, and biological seed cells for fabricating artificial nerve. Methods Recent literature relevant to artificial nerve, especially the achievement in physical material, chemical matrix and biological seed cells for fabricating artificial nerve, were extensively reviewed. Results Polymers of polylactic acid or polyglycolic acid and their polymer, polymer of hyaluronic acid and glut-aldehyde, polymer of polyacrylonitrile and polyvinylchloride were artificial nerve materials with the properties of good biocompatibility and biodegradation. A conduit with multichannel and high percentage of pores was beneficial to the regeneration of nerve. The activated Schwann cells were excellent seeds of artificial nerve. A suitable chemical matrix, such as laminin and alginate, could promote the regeneration of nerve. Conclusion The successful fabrication of artificial nerve lies in the advance in the mechanism of nerve regeneration and physical material, chemical matrix and biological seed cells.
Objective To investigate the hemocompatibility of the acellular valved bovine jugular vein conduit (BJVC) treated with polyepoxy compound (PC), and discuss its application in cardiovascular surgery and tissue engineering in the future. Methods BJVC treated with PC was regarded as the experiment group and BJVC treated with glutaraldehyde (GA) was considered to be the control group. Rat blood was used for in vitro hemolytic test to calculate hemolytic rates of BJVC, and curve of absorbanceclotting time was drawn. Human blood was used to determine the level of D-dimeride and complement activation C3a des Arg, and test its hemocompatibility in vitro. We divided 20 canines into the experiment group (PC group, n=10) and the control group (GA group, n=10) by random digital table. The BJVC treated with PC or GA were implanted between the pulmonary artery and right ventricle. Ten months after the implantation, thrombus and histological observation were performed to evaluate the blood compatibility in vivo. Results The hemolytic rate in the PC group (0.23%) was lower than that in the GA group (0.35%), which was in accordance with the national standard of hemolytic test (lt;5%). The curve of absorbanceclotting time in the experiment group declined more slowly than that of the control group. The D-dimeride level in the experiment group was significantly lower than that of the control group (0.10±0.01 μg/ml vs. 0.12±0.02 μg/ml , t=3.277, P=0.004), but both of them were within the normal level. The level of complement C3a des Arg in the experiment group was significantly lower than that of the control group (0.74±0.09 μg/ml vs. 1.02±0.19 μg/ml, t=4.183, P=0.001). Eight canines survived 10 months after the implantation in both the two groups, and two other canines in each group died due to ventricular fibrillation. Three canines were discovered to have thrombus in the control group while no thrombus was observed in the experiment group. Conclusion Compared with GA, acellular BJVC treated with PC has superiority in hemocompatibility in vitro and vivo, and has potential application in clinical research and practice.
Abstract: Objective To evaluate a new type of treatment that reduces calcification of glutaraldehydetreated bovine jugular venous conduit (BJVC). Methods Fresh bovine jugular veins were treated with glutaraldehyde, followed by Triton X-100 and epoxy chloropropane (EC+Tr group). We compared the group’s appearance, histology, shrinkage temperature, tensile strength, and elongation at break with those of a fresh group, and with a group treated with glutaraldehyde only (GA group). We then implanted the EC+Tr and GA group BJVCs subcutaneously into the backs of SD rats and left them for eight weeks (n=8). The morphologic properties and inflammatory response of the test specimens were evaluated by HE staining. The tissue calcium content was determined by atomic absorption spectrophotometer. Results The shrinkage temperature, tensile strength, and elongation at break of the EC+Tr group were significantly higher than those of the fresh group (86.15±0.92 ℃ vs. 69.94±0.92 ℃,t=35.239, P=0.000; 5.31±0.14 mPa vs.3.15±0.95 mPa,t=6.362, P=0.000; 265.11%±27.80% vs. 16521%±25.06%,t=7.550, P=0.000) and of the GA group (86.15±0.92 ℃ vs. 82.73±1.28 ℃, t=6.137, P=0.000; 5.31±0.14 mPa vs. 4.52±0.56 mPa,t=3.871, P=0.002; 265.11%±27.80% vs.237.85%±17.41%,t=2.351,P=0.034). The tissue structure of the subcutaneously implanted EC+Tr veins remained intact;degradation was slight and they contained few inflammatory cells. The calcium content of the EC+Tr group was lower than that of the GA group (51.22±2.69 μg/mg vs. 73.24±3.82 μg/mg, t=11.545，P=0.000). Conclusion Treatment with Triton X-100 and epoxy chloropropane modification with glutaraldehydetreated bovine jugular venous conduit was an effective way to prepare BJVC that avoided calcification.
Objective To explore a green route for the fabrication of thermo-sensitive chitosan nerve conduits, improve the mechanical properties and decrease the degradation rate of the chitosan nerve conduits. Methods Taking advantage of the ionic specific effect of the thermo-sensitive chitosan, the strengthened chitosan nerve conduits were obtained by immersing the gel-casted conduits in salt solution for ion-induced phase transition, and rinsing, lyophilization, and 60Co sterilization afterwards. The nerve conduits after immersing in NaCl solutions for 0, 4, 12, 24, 36, 48, and 72 hours were obtained and characterized the general observation, diameters and mechanical properties. According to the above results, the optimal sample was chosen and characterized the microstructure, degradation properties, and cytocompatibility. The left sciatic nerve defect 15 mm in length was made in 20 male Sprague Dawley rats. The autologous nerves (control group, n=10) and the nerve conduits (experimental group, n=10) were used to repair the defects. At 8 weeks after operation, the compound muscle action potential (CMAP) was measured. The regenerated nerves were investigated by gross observation and toluidine blue staining. The gastrocnemius muscle was observed by HE staining. Results With the increased ionic phase transition time, the color of the conduit was gradually deepened and the diameter was gradually decreased, which showed no difference during 12 hours. The tensile strength of the nerve conduit was increased gradually. The ultimate tensile strength showed significant difference between the 48 hours and 12, 24, and 36 hours groups (P<0.05), and no significant difference between the 48 hours and 72 hours groups (P>0.05). As a result, the nerve conduit after ion-induced phase transition for 48 hours was chosen for further study. The scanning electron microscope (SEM) images showed that the nerve conduit had a uniform porous structure. The degradation rate of the the nerve conduit after ion-induced phase transition for 48 hours was significantly decreased as compared with that of the conduit without ion-induced phase transition. The nerve conduit could support the attachment and proliferation of rat Schwann cells on the inner surface. The animal experiments showed that at 8 weeks after operation, the CMAPs of the experimental and control groups were (3.5±0.9) and (4.3±1.1) m/V, respectively, which showed no significant difference between the two groups (P<0.05), and were significantly lower than that of the contralateral site ［(45.6±5.6 m/V), P>0.05］. The nerve conduit of the experimental group could repair the nerve defect. There was no significant difference between the experimental and control groups in terms of the histomorphology of the regenerated nerve fibers and the gastrocnemius muscle. Conclusion The green route for the fabrication of thermo-sensitive chitosan nerve conduits is free of any toxic reagents, and has simple steps, which is beneficial to the industrial transformation of the chitosan nerve conduit products. The prepared chitosan nerve conduit can be applied to rat peripheral nerve defect repair and nerve tissue engineering.
Objective\ To search for suitable and multiple arterial grafts for myocardial revascularization, in order to avoid the long term problems of vein graft atherosclerosis. Methods\ Between October 1994 and April 2000, 456 consecutive patients underwent myocardial revascularization using radial artery and internal mammary artery. In coronary artery bypass grafting, minimally traumatic harvesting radial artery techniques and new pharmacologic antispasmodic agents was used. Results\ 448 internal mammary artery ...
Objective To summary the experience of extracardiac conduit total cavopulmonary connection (TCPC) and study the operative indication, design, method, and therapeutic efficacy. Methods 29 patients of extracardiac conduit TCPC were reviewed:the average age was 10 years. Of them, there were 9 cases of tricuspid atresia, 9 double inlet ventricle with left ventricular type, 3 mitral atresia, 3 corrected transposition of the great arteries with anatomically right ventricular hypoplasia and 5 double outlet of right ventricle with left ventricular hypoplasia. All patients underwent cardiopulmonary bypass, 12 cases with heart arrested, and 17 without heart arrested. In them, 20 cases’ superior vena cava were anastomosed directly to the upper margin of right pulmonary artery, 9 cases deviated to the left side of right pulmonary artery to enlarge the stoma. For the inferior vena cava stoma, 22 cases’ anterior walls of right atrium were partially incised, and sutured to the posterior wall, then anastomosed with Gore-Tex blood vessel prostheses and connected to pulmonary trunk, and the other 7 cases’ bottom of right atrium was totally incised, the proximal was closed, and the distal was anastomosised with Gore-Tex blood vessel prostheses and connected to the lower margin of right pulmonary artery, deviated to the right sidedness. Results 5 died in the first 22 cases, and the next 7 cases all survive. All patients were followed up for 3 months to 10 years with no late death. Of them, 12 cases had low cardiac output syndrome, and 11 cases of chylothorax. Conclusions Compared with other types of Fontan operation, the extracardiac conduit TCPC has better long-term effects in older or grown-up children. Nevertheless, strict operative adoption, reasonable operative design, refined procedures, carefully observation and treatment are the key points of improving therapeutic efficacy.
Objective To investigate the surgery experience of modified intra/extracardiac conduit total cavopulmonary connection (TCPC). Methods We retrospectively analyzed clinical data of 47 patients of complex congenital heart disease undergoing intra/extracardiac conduit total cavopulmonary connection in our hospital between January 2008 and December 2015. There were 29 males and 18 females with a median age of 7 years (range 4 to 9 years) and median body weight of 22 kg (range 14 to 38 kg). The heart echocardiography and cardiac imaging confirmed diagnosis suitable for TCPC surgery. Results There was no early death in the whole group. The mean pulmonary arterial pressure was 16 (12–20) mm Hg and the ventilation time was 14 (7–97) h. The main complications were intractable pleural effusion in 7 patients, low cardiac output syndrome in 3 patients, repeated supraventricular tachycardia in 1 patient. All the patients recovered after treatment. At the end of discharge, the percutaneous oxygen saturation was 85%–96% (92.6%±3.3%). The echocardiography showed the conduit pressure was 0–2 mm Hg. Patients were followed up for 1 to 7 years. Three patients were lost. One patient had intestinal nutrition loss, receving repeated pleural effusion, the treatment was ineffective, died after 4 years. Four patients of repeated pleural effusion improved after treatment. One patient repeated attacks supraventricular tachycardia within 1 year, controlled by amiodaronum, already stopped about 28 months. No recurrence occurred. All survivors were in New York Heart Association (NYHA) functional class Ⅰ or Ⅱ, with good activity tolerance. Conclusion The modified intra/extracardiac conduit TCPC combines the advantages of both the lateral tunnel and the extracardiac conduit. The operation is simple, used in the treatment of complex congenital heart disease. The short-term and mid-term results are encouraging.
Objective To assess the mid- and long-term outcomes of right ventricular outflow tract reconstruction for children with congenital heart disease. Methods We retrospectively analyzed the clinical data of 3 138 children with complex congenital heart disease in right heart system admitted to our hospital from January 2007 to January 2017. There were 1 660 males and 1 478 females. The age at surgery was 9 days to 84 months, and the body weight was 2.2 to 28.6 kg. Pulmonary patch enlargement was performed in 2 335 patients (1 477 patients of valve-sparing repair and 858 patients of transannular repair); autologous tissue (direct anastomosis, left auricle or pericardial conduit) was used to connect with right ventricle in 289 patients; extracardiac conduits were used for reconstruction in 514 patients. Results There were 181 in-hospital deaths with a mortality of 5.8%. The early postoperative causes of death were low cardiac output syndrome (LCOS), severe pulmonary hypertension and right heart failure. Fifteen patients died of cardiac insufficiency or sudden death during follow-up (6–27 months postoperatively). The echocardiography showed 408 patients with right ventricular outflow tract obsturction (RVOTO), 340 patients with pulmonary trunk or branches stenosis, 609 with pulmonary regurgitation (morderate or severe). 12.6% (394/3 138) of patients underwent reintervention or reoperation with 39 deaths. About 92.4% of patients exhibited an improvement of New York Heart Association (NYHA) functional class from Ⅲ or Ⅳ preoperatively to Ⅰ or Ⅱ at follow-up. Conclusion The anatomical structure of right ventricular outflow tract is complicated and various, and each operation method has different strengths and favorable outcomes. The operation should be individually designed according to pathological types, anatomical features, clinical symptoms and operation conditions.
OBJECTIVE To explore the effect of basic fibroblast growth factor (bFGF) combined with autogenous vein graft conduit on peripheral nerve regeneration. METHODS Fifty four New Zealand rabbits were divided into three groups. The main trunk of sciatic nerve of rabbit in one side was severed and bridged by autogenous vein. 0.2 ml bFGF solution (4,000 U/ml) was intravenously injected to the vein graft conduit as group A, the same amount of saline solution as group B, and no solution injection as group C. Microscopic examination, axon video analysis and nerve conduct velocity were performed at the 10th, 30th, and 100th day after operation. RESULTS The nerve fibers were grown into vein graft conduit in all groups at 30th after operation, they were more and regular in group A than that of group B and C, and the axon regeneration rate in group A was more than that of group B and C. CONCLUSION bFGF combined with autogenous vein graft conduit can markedly promote nerve regeneration.