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 Comparing postoperative change of blood gas and hemodynamic status in patients underwent a right ventricletopulmonary artery (RVPA) conduit or a modified BlalockTaussig (mBT) shunt for pulmonary atresia with ventricular septal defect and without major arterial pulmonary collaterals (MAPCAs), to affirm the effect on oxygen supply /demand with different procedure. Methods From July 2006 to October 2007, 38 patients with pulmonary atresia and ventricular septal defect without MAPCAs were divided into two groups according to different procedures: RVPA group (n=25) and mBT group (n=13).Perioperative mortality, blood gas and hemodynamic data during postoperative 48 hours, including heart rate, blood pressure, systemic oxygen saturation, mixed venous oxygen saturation, oxygen excess factor, inotropic score were compared in both groups. Results The difference in the mortality between RVPA group (4.0％，1/25) and mBT group （7.7％，1/13) showed no statistical significance（Pgt;0.05）. The total of 33 patients were followed up, the followup time was from 6 to 18 months.11 patients (4 patients in mBT group, 7 patients in RVPA group) underwent corrected procedures during 9 to 18 months after palliative procedures, one case died of elevated pulmonary vascular resistance and right ventricle failure. The mixed venous oxygen saturation at 24h and 48h after surgery were higher than that at 6h after surgery (Plt;0.01) both in RVPA group and mBT group. The systolic blood pressures at 6h, 24h, 48h after surgery in RVPA group were lower than those in mBT group (P=0.048，0.043， 0.045)，the mean systemic blood pressures in RVPA group were higher than those in mBT group (P=0.048, 0.046, 0.049),the diastolic blood pressures in RVPA group were higher than those in mBT group (P=0.038, 0.034, 0.040)， the inotropic scores in RVPA group were lower than those in mBT group (P=0.035， 0.032，0.047). Conclusion The blood pressures and inotropic scores are found significantly different in RVPA conduit and mBT procedures, while postoperative systemic oxygen delivery areequivalent. Both RVPA and mBT patients decline to nadir in hemodynamic status at 6 h after surgery.
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 study the result of using nerve conduit coated with chitin and filled with a guide-fiber to repair peripheral nerve defect. Methods Twenty-four female adult SD rats were made the model of 14 mm-gap on bilateral sciatic nerve under sterile condition. The rats were randomly divided into 4 groups(n=6),group A: polymer polyglycolic-lactic acid(PGLA) nerve conduit coated with chitin and filled with a guide-fiber as experimental group to repair 14 mm gap of rat sciatic nerve；group B: PGLA nerve conduit coated with chitin； group C: PGLA nerve conduit； group D: autograft (control group). The repair result was evaluated by normal observation, EMG testing and S-100 histological immunostaining analysis 4 and 12 weeks after operation.Results Four weeks after the operation，there were new regenerated immature fibers in groups A,B and C, 12 weeks after the operation, the regenerated nerve fibers were seen to have bridged the gap. There were myelinated fibers equably distributed and rarely newgenerated nerve fibers in distal parts of group D. The repair result of PGLA nerve conduit coated with a chitin and filled with guide-fiber was better than that of groups B and C（Plt;0.05）. There was significant difference of nerve fiber diameter，thickness of myelin sheath and fiber density in group D from those in groups A, B and C（Plt;0.05），but there were degenerative changes such as vacuoles insheaths and myelin separation in proximal and few new regenerated nerve fibers in distal parts of group D. Conclusion PGLA nerve conduit coated with chitin and filled with a guide-fiber offers a possible substitute for the repair of peripheral nerve defect.
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.
ObjectiveTo describe the research progress of silk-based biomaterials in peripheral nerve repair and provide useful ideals to accelerate the regeneration of large-size peripheral nerve injury. Methods The relative documents about silk-based biomaterials used in peripheral nerve regeneration were reviewed and the different strategies that could accelerate peripheral nerve regeneration through building bioactive microenvironment with silk fibroin were discussed. Results Many silk fibroin tissue engineered nerve conduits have been developed to provide multiple biomimetic microstructures, and different microstructures have different mechanisms of promoting nerve repair. Biomimetic porous structures favor the nutrient exchange at wound sites and inhibit the invasion of scar tissue. The aligned structures can induce the directional growth of nerve tissue, while the multiple channels promote the axon elongation. When the fillers are introduced to the conduits, better growth, migration, and differentiation of nerve cells can be achieved. Besides biomimetic structures, different nerve growth factors and bioactive drugs can be loaded on silk carriers and released slowly at nerve wounds, providing suitable biochemical cues. Both the biomimetic structures and the loaded bioactive ingredients optimize the niches of peripheral nerves, resulting in quicker and better nerve repair. With silk biomaterials as a platform, fusing multiple ways to achieve the multidimensional regulation of nerve microenvironments is becoming a critical strategy in repairing large-size peripheral nerve injury. Conclusion Silk-based biomaterials are useful platforms to achieve the design of biomimetic hierarchical microstructures and the co-loading of various bioactive ingredients. Silk fibroin nerve conduits provide suitable microenvironment to accelerate functional recovery of peripheral nerves. Different optimizing strategies are available for silk fibroin biomaterials to favor the nerve regeneration, which would satisfy the needs of various nerve tissue repair. Bioactive silk conduits have promising future in large-size peripheral nerve regeneration.
ObjectiveTo summarize clinical experience and outcomes of extracardiac conduit total cavopulmonary connection (TCPC)for surgical treatment of complex congenital heart diseases. MethodsClinical data of 52 patients who underwent extracardiac conduit TCPC from September 2006 to December 2012 in Department of Cardiac Surgery, Guangzhou General Hospital of Guangzhou Military Command were retrospectively analyzed. There were 12 patients who received one-stage extracardiac conduit TCPC. There were 40 patients who received two-staged extracardiac conduit TCPC after bidirectional Glenn procedure. Clinical data of all the patients were analyzed. Mortality, morbidity, length of hospital stay and intensive care unit (ICU)stay, mechanical ventilation time, change of arterial oxygen saturation (SaO2)were compared between the 2 groups. ResultsTwo patients (3.8%)died postoperatively including 1 patient with severe low cardiac output syndrome and another patient with multiple organ dysfunction syndrome. Fifty patients were discharged successfully. Mechanical ventilation time, length of ICU stay and hospital stay of the 40 patients who received two-stage extracardiac conduit TCPC were significantly shorter than those of the 12 patients who received one-stage extracardiac conduit TCPC. There was no statistical difference in postoperative morbidity, SaO2 (two-staged vs. one-staged:93%±3% vs. 94%±3%)or mortality (two-staged vs. one-staged:2.5% vs.8.3%)between the 2 groups (P > 0.05). Forty-five patients (90%)were followed up for 6-52 months, and there was no death during follow-up. At 3 months after TCPC, all the patients had heart function of class I or II, and echocardiography showed patent cavopulmonary anastomosis. ConclusionExtracardiac conduit TCPC is a simple procedure, can produce more physiological hemodynamic results, and can be performed for patients who cannot undergo biventricle procedure. Compared with one-stage extracardiac conduit TCPC, two-staged extracardiac conduit TCPC has wider surgical indications, can produce better postoperative recovery, and is easier to perform.
ObjectiveTo investigate the effect of cells in the epimysium conduit (EMC) on the regeneration of sciatic nerve of mice.MethodsThe epimysium of the 8-week-old male C57BL/6J enhanced green fluorescent protein (EGFP) mouse was trimmed to a size of 5 mm×3 mm, and prepared in a tubular shape (ie, EMC). Some epimysia were treated with different irradiation doses (0, 15, 20, 25, 30, 35 Gy) to inhibit cells migration. Then the number of migrating cells were counted, and the epimysia with the least migrating cells were selected to prepare EMC. Some epimysia were subjected to decellularization treatment and prepared EMC. HE and Masson staining were used to identify the decellularization effect. Twenty-four C57BL/6J wild-type mice were used to prepare a 3-mm-long sciatic nerve defect of right hind limb model and randomly divided into 3 groups (n=8). EMC (group A), EMC after cell migration inhibition treatment (group B), and decellularized EMC (group C) were used to repair defects. At 16 weeks after operation, the midline of the regenerating nerve was taken for gross, toluidine blue staining, immunofluorescence staining, and transmission electron microscopy.ResultsAt 15 days, the number of migrating cells gradually decreased with the increase of irradiation dose. There was no significant difference between 30 Gy group and 35 Gy group (P>0.05); there were significant differences between the other groups (P<0.05). The epimysium after treatment with 35 Gy irradiation dose was selected for thein vivo experiment. After the decellularization of the epimysium, no nucleus was found in the epimysium and the epimysium could be sutured to prepare EMC. At 16 weeks after operation, the nerves in all groups were recanalized. The sciatic nerve was the thickest in group A, followed by group B, and the finest in group C. Immunofluorescence staining showed that the EGFP cells in group A were surrounded by regenerated axons. Toluidine blue staining and transmission electron microscopy observation showed that the number of regenerated axons and the thickness of regenerated myelin sheath in group A were significantly better than those in groups B and C (P<0.05). There was no significant difference between groups B and C (P>0.05).ConclusionThe cellular components of the epimysium participate in and promote the regeneration of the sciatic nerve in mice.
ObjectiveTo evaluate the clinical outcome of valved homograft conduits (VHC) used for right ventricular outflow tract (RVOT) reconstruction in Fuwai Hospital in recent 13 years, and explore the factors influencing the long-term durability of VHC. MethodsClinical data of patients using VHC for RVOT reconstruction in Fuwai Hospital from November 2007 to October 2020 were retrospectively analyzed. The Kaplan-Meier survival curve was used to evaluate survival, VHC reintervention and VHC dysfunction. Cox proportional risk regression model was used to analyze the risk factors for VHC dysfunction. ResultsFinally 251 patients were enrolled, including 145 males and 106 females. The median age at surgery was 6.0 (0.3-67.0) years. Early death occurred in 5 (2.0%) patients. The follow-up was available for 239 (95.2%) patients, with the follow-up time of 0.3-160.0 (61.3±45.4) months. Five patients died during the follow-up, and the 1-year, 6-year, and 13-year survival rates were 96.6%, 95.5% and 95.5%, respectively. Eight patients received VHC reintervention during the follow-up, and freedom rates from VHC reintervention were 100.0%, 97.1% and 82.4% at 1 year, 6 years and 13 years, respectively. A total of 226 patients were followed up by echocardiography after discharge, with the follow-up time of 0.2-138.0 (48.5±40.5) months. During the follow-up, 46 (20.4%) patients developed VHC dysfunction, and freedom rates from VHC dysfunction at 1 year, 5 years, and 10 years were 92.6%, 79.6% and 59.3%, respectively. Univariate Cox regression analysis showed that age<6 years and VHC diameter<19 mm were risk factors for VHC dysfunction (P=0.029, 0.026), but multivariate regression analysis only indicated that age<6 years was an independent risk factor for VHC dysfunction (P=0.034). ConclusionThe early and late outcomes of VHC used for RVOT reconstruction are satisfactory, and the long-term durability of VHC is also optimal. In addition, age<6 years is an independent risk factor for VHC dysfunction.
【Abstract】Objective The injury induced by hepatic artery ischemia (HAI) in the liver transplantation procedure and the protective effects of using hepatic artery bridge-conduit (HABC) technique were studied. Methods Thirtytwo dogs were randomly divided into 4 groups: control, HAI 30 min, HAI 2 h and HABC groups. We observed the pathological changes of hepatocytes and biliary tract tissues and the microstructure of chondriosome, which were based on the model of auto-orthotopic liver transplantation in dogs. Biochemical and spectrophotometric methodswere used to evaluate the content of MDA and SOD, SDH activities in the graft liver tissue respectively. Results The pathologic and electrical microscopic changes of hepatocytes and epithelial cells of bile ducts were found in HAI 30 min and HAI 2 h groups,while the content of MDA increased to （1.652±0.222） nmol/mg prot and (2.379±0.526) nmol/mg prot, and SOD activity decreased to (11.15±3.9) U/mg prot and (9.47±3.4) U/mg prot. At the same time, SDH activity was also down-regulated to 0.362±0.019 and 0.281±0.029. Compared with control group, the differences were significant (Plt;0.05, Plt;0.01). But these changes of functional index caused by HAI injury were not significant in HABC group. Conclusion The HABC technique can not only avoid HAI injury during operation but also alleviate the occurrence of complication after transplantation, especially the biliary tract complication.