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.
ObjectiveTo study the effect of the loaded concentration gradient of nerve growth factor (NGF) immobilized conduit on rat peripheral nerve defect repair. MethodsThe peripheral nerve conduits made of poly (ε-caprolactone)-block-poly (L-lactide-co-ε-caprolactone) were prepared with uniform loads or concentration gradient loads by combining differential absorption of NGF/silk fibroin (SF) coating, and the gradient of NGF was immobilized in the nerve conduits. ELISA method was used to exam the NGF release for 12 weeks in vitro. Twenty-four male Sprague Dawley rats (weighing, 220-250 g) were selected to establish the right sciatic nerve defect model (14 mm in length) and randomly divided into 4 groups according to repair methods. The transected nerve was bridged by a blank conduit without NGF in group A, by a conduit containing uniform loads of NGF in group B, by a conduit concentration gradient loads of NGF in group C, and by the autogenous nerve segment in group D. The gross observation, electrophysiological examination, histological observation, and transmission electron microscope observation were carried out to assess the nerve regeneration at 12 weeks after surgery. ResultsThe cumulative release amount of NGF was (14.2±1.4) ng/mg and (13.7±1.3) ng/mg in gradient of NGF loaded conduits and uniform NGF loaded conduits respectively at 12 weeks, showing no significant difference (t=0.564, P=0.570). All the animals survived to completion of the experiment; plantar ulcers occurred at 4 days, which healed at 12 weeks; groups C and D were better than groups A and B in ulcerative healing. At 12 weeks after surgery, the compound muscle action potential of group A was significantly lower than that of groups B, C, and D (P<0.05), and group B was significantly lower than groups C and D (P<0.05), but no significant difference was found between groups C and D (P>0.05). The axon density of group C was significantly higher that of groups A, B, and D (P<0.05); group D was significantly higher than groups A, B, and C, and group C was significantly higher than groups A and B in the axon number, axon diameter, and area of muscle fiber (P<0.05); the thickness of myelin sheath of groups C and D was significantly larger than that of groups A and B (P<0.05), but no significant difference was found between groups C and D (P>0.05). ConclusionGradient of NGF loaded nerve condnits for rat sciatic nerve defect has similar results to autogenous nerve, with a good bridge, which can promote the sciatic nerve regeneration, improve the myelinization of the regenerating nerve, and accelerate the function reconstruction of the regenerating nerve.
Objective To study the inflammation response and the biocompatibil ity of valved bovine jugular vein conduit (BJVC) and valved bovine jugular vein patch (VBJV-P) in treating complex congenital heart disease (CHD). Methods From December 2007 to March 2008, 16 patients with complex CHD were treated. Of 16 patients, 6 underwent conjunction right ventricular to pulmonary artery with BJVC and broaden right ventricular outflow tract (RVOT) with VBJV-P (BJVC group), and 10 underwent broaden RVOT with self pericardial patch (control group). In BJVC group, there were 3 males and 3 females, aging (5.6 ± 3.6) years, and including 1 case of type I truncus arteriosus, 1 case of type I truncus arteriosus with ventricular septal defect and patent foramen ovale, 1 case of congenital pulmonary atresia with ventricular septal defect and patent arterial duct, and 3 cases of Fallot’s tetrad. In control group, there were 5 males and 5 females, aging(4.3 ± 3.1) years, all being Fallot’s tetrad. The periphery vein blood of the two groups was collected during operation and after operation, and the levels of cytokine were detected with ELISA method. Meanwhile the cl inical data of the two groups were collected. Results There were no significant differences at levels of TNF-α and IL-6 between BJVC group and control group 1 week after operation (P gt; 0.05), and there was significant difference at level of IL-10 [(25.7 ± 5.0) pg/mL vs (19.5 ± 4.7) pg/ mL, P lt; 0.05]. There were no significant differences at levels of IL-6 and IL-10 within groups both in control group and in BJVC group (P gt; 0.05) between 1 week after operation and the anesthesia inducing period. And there was significant difference at level of TNF-α in BJVC group [(77.0 ± 1.6) pg/mL vs (82.9 ± 1.3) pg/mL, P lt; 0.05] and in control group [(78.6 ± 3.4) pg/mL vs (83.1 ± 1.9) pg/mL, P lt; 0.05] between 1 week after operation and the anesthesia inducing period. There were no statistically significant differences (P gt; 0.05) in leukocyte count and body temperature between BJVC group and control group. The X-ray films showed no abnormal ity in BJVC group and control group before operation and after operation. No hepatic and renal dysfunction occurred in control group; and 2 patients had hepatic dysfunction, which may be caused by antibiotics. Conclusion BJVC has a good biocompatibil ity in treating complexty CHD.
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.
The choice of the graft conduit for coronary artery bypass grafting (CABG) has significant implications both in the short-and long-term. The patency of a coronary conduit is closely associated with an uneventful postoperative course, better long-term patient survival and superior freedom from re-intervention. The internal mammary artery is regarded as the primary conduit for CABG patients, given its association with long-term patency and survival. However, long saphenous vein (LSV) continues to be utilized universally as patients presenting for CABG often have multiple coronary territories requiring revascularization. Traditionally, the LSV has been harvested by creating incisions from the ankle up to the groin termed open vein harvesting (OVH). However, such harvesting methods are associated with incisional pain and leg wound infections. In addition, patients find such large incisions to be cosmetically unappealing. These concerns regarding wound morbidity and patient satisfaction led to the emergence of endoscopic vein harvesting (EVH). Published experience comparing OVH with EVH suggests decreased wound related complications, improved patient satisfaction, shorter hospital stay, and reduced postoperative pain at the harvest site following EVH. Despite these reported advantages concerns regarding risk of injury at the time of harvest with its potential detrimental effect on vein graft patency and clinical outcomes have prevented universal adoption of EVH. This review article provides a detailed insight into the technical aspects, outcomes, concerns, and controversies associated with EVH.
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 investigate the effect of folic acid coated-crosslinked urethane-doped polyester elastomer (fCUPE) nerve conduit in repairing long distance peripheral nerve injury. MethodsThirty-six 3-month-old male Sprague Dawley rats weighing 180-220 g were randomly assigned to 3 groups, each consisting of 12 rats: CUPE nerve conduit transplantation group (group A), fCUPE nerve conduit transplantation group (group B), and autologous nerve transplantation group (group C), the contralateral healthy limb of group C served as the control group (group D). A 20-mm-long sciatic nerve defect model was established in rats, and corresponding materials were used to repair the nerve defect according to the group. The sciatic function index (SFI) of groups A-C was calculated using the Bain formula at 1, 2, and 3 months after operation. The nerve conduction velocity (NCV) of the affected side in groups A-D was assessed using neuroelectrophysiological techniques. At 3 months after operation, the regenerated nerve tissue was collected from groups A-C for S-100 immunohistochemical staining and Schwann cell count in groups A and B to compare the level of nerve repair and regeneration in each group. ResultsAt 3 months after operation, the nerve conduits in all groups partially degraded. There was no significant adhesion between the nerve and the conduit and the surrounding tissues, the conduit was well connected with the distal and proximal nerves, and the nerve-like tissues in the conduit could be observed when the nerve conduit stents were cut off. SFI in group A was significantly higher than that in group C at each time point after operation and was significantly higher than that in group B at 2 and 3 months after operation (P<0.05). There was no significant difference in SFI between groups B and C at each time point after operation (P>0.05). NCV in group A was significantly slower than that in the other 3 groups at each time point after operation (P<0.05). The NCV of groups B and C were slower than that of group D, but the difference was significant only at 1 month after operation (P<0.05). There was no significant difference between groups B and C at each time point after operation (P>0.05). Immunohistochemical staining showed that the nerve tissue of group A had an abnormal cavo-like structure, light tissue staining, and many non-Schwann cells. In group B, a large quantity of normal neural structures was observed, the staining was deeper than that in group A, and the distribution of dedifferentiated Schwann cells was obvious. In group C, the nerve bundles were arranged neatly, and the tissue staining was the deepest. The number of Schwann cells in group B was (727.50±57.60) cells/mm2, which was significantly more than that in group A [(298.33±153.12) cells/mm2] (t=6.139, P<0.001). ConclusionThe fCUPE nerve conduit is effective in repairing long-distance sciatic nerve defects and is comparable to autologous nerve grafts. It has the potential to be used as a substitute material for peripheral nerve defect transplantation.
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.
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.