Objective To study the mechanism of restenosis of the vein graft and the effect of the grafting injury to the vein graft. Methods One side of the 36 healthy rabbits was randomly chosen as the V-A group, and on the side a 1.5cmlong femoral vein was obtained, and an 0.5-cm-long segment of the obtained femoral vein was separated as the control group. The remaining 1-cm-long femoral vein was inverted and was autogenously implanted into the femoral artery on the same side of the rabbit. The other side of the rabbits was chosen as the V-V group, and on this side a 1-cm-long femoral vein was obtained ex vivo and then was sutured in situ. The vein grafts on both sides were harvested 4 weeks after operation. The specimens from the harvested vein grafts were stained with HE and theelastic fiber Victoria blue for an observation on the histological changes in the walls of the vein grafts, and the specimens were also stained by the immunohistochemistry of the proliferating cell nuclear antigen (PCNA) for an observation on the wall cell proliferation of the vein grafts. The changes in the ultrastructure of the proliferated wall cells of the vein grafts were observed under electron microscope. The two sides of the rabbits were compared. Results The smooth muscle cells of the media developed hyperplasia, but theintima and the media remained unchanged in their thickness (3.50±0.41 μm, 12.23±1.59 μm) in the V-V group, with no difference when compared with the control group (3.40±0.37 μm, 12.14±1.62 μm); however, when compared with the V-A group (25.60±3.21 μm, 21.30±2.47 μm),there was a significant difference in the thickness (Plt;0.01). There were no cells positive for PCNA by the immunohistochemistry examination in the control group. The cells positive for PCNA were found in the intima and the media in both the V-V group and the V-A group; however, the percentageof the cells positive for PCNA in the intima and the media was significantly greater in the V-A group than in the V-V group (16.4%±1.9% and 36.5%±3.7% vs 5.9%±1.3% and 23.4%±3.4%, Plt;0.01). In the V-V group, the endothelial cell could be observed under transmis-sion electron microscope, which was flat and had a processlike villus at its free end, and the endothelial cells were closely arranged andhad hyperplasia of the smooth muscle cells in the media. But in the V-A group,the endothelial cells had an obvious hyperplasia with an irregular shape and a widened space between the cells, and in the intima a great amount of the smooth muscle cells could be observed, which had a broken basement membrane. The smooth muscle cells also had an obvious hyperplasia in the media. The shape and alignment of the endothelial cells in the control group were similar to those in the V-V group, but the hyperplasia of the smooth muscle cells was not observed in the media. Conclusion The grafting injury can cause hyperplasia ofthe vascular wall cells, and if the hemodynamics is changed simultaneously, more serious hyperplasia and cell migration can be observed from the media to the intima, resultingin restenosis of the blood vessels. So, if we can reduce the grafting injury and improve the microcirculation of the vein graft, we may find out the methods ofpreventing restenosis of the vein graft. The animal model of the V-V graftcan help to understand the mechanism of restenosis of the vein graft.
Objective To investigate the results and applicationvalue of crotch-shaped vein grafts in repairing defects of the vessels with a large diameter.Methods From June 1998 to October 2003, 35 cases of vesseldefects with a large diameter were repaired with crotch-shaped vein graft (29 males and 6 females,aged 18 to 45 years with an average of 25.7 years ). The locations of defects were femoral artery in 25 cases, popliteal artery in 2 cases, femoral vein in 7 cases, and subclavian vein in 1 case. The interval between injure and operatioinwas 1-8.5 hours (4.1 hours on average).The blood flows of trouble and healthy vascular were determined with Doppler detector and compared preoperatively andpostoperatively. Results All the anastomotic stomas were patent in 35 cases. Thirty-one cases were followed up 6 weeks to 24 months (9.5 months on average), the patent rate was 100%, no case occurred vasospasm or tromboembolism; 2 cases occurred stomal leak and became hematoma, 3 cases occurred muscular necrosis, and the 5 cases achieved primary healing after secondary operation. The Doppler results showed that there was statistically significant difference in the blood flow betweenpostoperation and preoperation (Plt;0.01), but no statistically significant difference when compared the trouble vascular after operation with healthy vascular (Pgt;0.05). Conclusion The methodof crotch-shaped vein grafts is safe and effective in repairing defects of vessels with a large diameter,which is easy to draw materials and handy to operate. It has a promising value in clinical application.
Objective To study the effect of vein-occlusion on the replanted limb survival in SD rats at different stages. Methods Twenty-five adultSD rats were randomly divided into 5 groups according to the time of the femoral vein occlusion after the replanted limbs:2- ,3- ，4 -，6-，and 8- day groups. The limbs were observed through naked eye, measurement of dermal temperature and angiography. Results No formation of collateral veinlet was found, and necrosis wasseen in the replanted limbs of 2- , 3- day groups. Reflux-vein was gradually increased in the replanted limbs of 4，6，and 8 day groups. Angiographic score of capillary density and dermal temperaturein the thigh muscles were greater in groups 4-，6-，and 8- day than in groups 2 and 3 day. Conclusion Within 2 and 3 days，the replanted limbs of SD rats will necrose because of vein-occlusion; and 4 days later the replanted limbs can survive depending on the reflux-vein of new collateral veinlet.
Objective To construct vectors that express phosphatidylinositol-3-kinase, catalytic, beta polypeptide （PIK3cb） shRNA in eukaryon plasmid catalyzed by PI3K in rat, then test their effects on intimal hyperplasia in transplanted vein graft. Methods One hundred and fifty SD rats were randomly divided into six groups （n=25, in each group）: blank (25% Pluronic F-127), shRNA-1, shRNA-2, 1/2 （shRNA-1+shRNA-2）, negative control (pGenesil-1 scramble shRNA) and positive control （wortmannin） group. The jugular vein in rats were interpositioned autologously into the common carotid artery. shRNA and 25% Pluronic F-127 were mixed and coated around the transplanted vein in three PIK3cb shRNA groups. Every 5 samples were removed according to the time point (1, 3, 7, 14 and 28 days after operation), respectively. The thickness of intima and neointima area were calculated and analyzed by computer system. The PCNA expression was detected by Western blot and SP immunohistochemistry. Results The intimal thickness of three PIK3cb shRNA groups were lower than those in the blank group and negative control group on day 3, 7, 14, 28 after operation (P＜0.05); The neointima area in three PIK3cb shRNA groups (except shRNA-2 group on day 3, 7) began to decrease significantly from day one (P＜0.05). The protein expression of PCNA in three PIK3cb shRNA groups on day 3 after operation were decreased compared with blank group and negative group (P＜0.05). The percentage of the PCNA positive cells area in three PIK3cb shRNA groups were significantly lower than those in blank group and negative control group in each time point (Plt;0.05). There were no significant differences between blank and negative control group in different time points (Pgt;0.05). Conclusion The PIK3cb shRNA can effectively inhibit the proliferation of vascular smooth muscle cell, which may provide a new gene therapy for the prevention of vein graft restenosis after bypass grafting.
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.
Objective To repair defects at both ends of theblood vessels with a considerable disparity in the diameter of the both sides or with a large diameter in extremities by phleboplasty of branched and double autogenous veins. Methods Three kinds of phleboplasties——funnel-shaped, raincape-shaped and transposed Y-shaped were designed. Experiments in fresh blood vessels in vitro were completed successfully. These methods were used clinically to repair injured external iliac veins, femoral arteries and veins, and popliteal arteries and veins, to replant severed fingers and to transplant toenail flaps on thumbs by harvesting autogenous great saphenous veins,small saphenous veins and forearm veins in 36 cases, including 35 cases in emergency operation and 1 case in selective operation.The length of grafted blood vessels ranged from 1.0 cm to 15.0 cm. Results The phleboplasties of funnel-shaped could enlarge the diameter by 1.0-1.25 times inanastomotic stomas. The phleboplasty of raincape-shaped could enlarge the diameter large enough to meet the demands for various blood vessels in extremities. The phleboplasty of transposed Y-shaped could provide large vein transplants. In36 grafted veins, 35 were in patency. The blood supply in extremities was normal.ConclusionThe funnel-shaped and raincape-shaped phleboplasties of branched veins can enlarge the anastomotic stomas of grafted veins. The transposed Y-shaped phleboplasty of double femoral veins is an ideal way to repair injured primaryblood vessels with a considerable disparity in the diameter of the both sides or with a large diameter in extremities.
ObjectiveTo study the cell apoptosis and the dynamic expression and significance of apoptosis-related genes in graft veins. MethodsA rat experimental model of autogenous graft vein was established by transplanting the right external jugular vein to infrarenal abdominal aorta in 100 Wistar rats. TUNEL and immunohistochemistry were used to detect the apoptosis, the expression of apoptosis-related genes bcl-2 and bax in vascular smooth muscle cells (VSMCs) of graft veins. ResultsWithin the 8 weeks after transplantation, the apoptotic VSMCs in the graft veins were much more than those in the control group with the apoptotic rate reaching the peak〔（28.5±16.6）%〕 on the 2nd week and dropping to （8.1±2.8）% during the 4th to 8th week. There was statistical difference compared to the control group 〔(0.5±0.2)%, P＜0.01〕. From 1 to 2 weeks, the positive rate of bcl-2 was (22.1±5.4)% which was higher than that of the control group and the 4-8 week group (P＜0.01); from 1 to 6 weeks, the expression of bax was higher than that of the control group 〔(5.5±2.3)%〕 and the postoperative 8th week group 〔(8.2±2.9)%, P＜0.01〕.Conclusionbcl-2 and bax protein may be involved in the regulation of apoptosis of VSMCs. Apoptosis of VSMCs may be an important factor in graft remodeling and graft vein stenosis.
In order to develope a new method to overcome the difficulties in anastomosis of blood vessels with different diameter, phleboplasty was utilized at the join-point to expand the diameter of branched vein graft, with a funnel-shaped stoma formed consequently. After successfully experimented in fresh blood vessels in vitro, the method was practised clinically to repair injured arteries in extremities, with the outcome that phleboplasty of branched vein graft could enlarge the diameter by 1-1.25 times, and with satisfied effects in 3 clinic cases. So, the conclusion was that: phleboplasty of branched vein graft was a new effective and convinient method to repair injured arteries with different diameters
The femoral veins were excised from 28 dogs and distended with pressure of 40, 80 and 120 kPa, respectively before grafted to femoral arteries. The veins were harvested at different times and Pollak sections were prepared which revealed different stains of elastin, collagen and smooth muscle in each section. The sections were led to image analysis system to computerize the relative contents of theabove components. The results were as follows: Elastin decreased significantly at 4 weeks (P lt;0.01), and was constant between 4 and 16 weeks. No statistical difference was found in 40, 80 kPa and the control group (P gt;0.05), but the elastin of 120 kPa group by the 16th week was still decreasing. Collagen of each group had no difference, but C/E increased significantly with time. Smooth muscle contents were correlated positively with time, and negatively with the pressure at 1 week, then positively with the pressure at 16th week. The changes of the above trends were the same as development of intimal hyperplasia. The contentions were the value of C/E was determined by the arterial pressure but that of 120 kPa pressure was more higher. The preimplant pressure distension was a possible significantfactor leading to excessive intimal hyperplasia of early and middle stage of autogenous vein grafts.
【Abstract】ObjectiveSome studies have demonstrated that recombinant adenoviruses are efficient vectors for gene transfer to the venous wall and AdCMV.tk encoded thymidine kinase can be used to reduce restenosis. In this study AdCMV.tk was apply to human vein smooth muscle cells (SMC) and organ cultured saphenous veins to study its effects on proliferation of SMCs and reduction of intimal hyperplasia. MethodsThe adenovirus vector transferred tk gene and mark gene lacZ to the SMC of human saphenous veins and organ cultured vein segments. Various concentrations ganciclovir (GCV) were contained in culture media. The efficiency of gene transfer was studied by using Xgal staining. The proliferation of SMC was monitored by the method of trypan blue exclusion. The bystander effect was observed by mixed cell culture. After vein segments treated by AdCMV.tk+GCV and cultured for 14 days, HE and VG staining were carried out and intimal thickness was analysis by computer image system. ResultsAdenovirus vector could infect saphenous vein SMC efficiently both in cultured SMCs and organ cultured vein segments. Gene expression sustained 14 d at least. The inhibition of SMCs proliferation in vitro was a positive correlation in GCV concentrations and the levels of tk expression. The proliferation of SMCs transfectered lacZ wasn’t restrained by GCV (P＜0.05). In mixed cell experiment there was at least 55% reduction in total cell number when as few as 10% of the cells express tk. Assessment of this “suicide gene strategy” in saphenous vein organ culture model demonstrated that veins treated with AdCMV.tk+GCV had a significant reduction at 14 days in the intimal thickness compared to control group (P＜0.01). ConclusionThe results suggest that adenovirusmediated gene transfer of tk along with GCV administration may be a useful strategy to treat the proliferation of intimal hyperplasia of transplanting saphenous veins. Bystander effects are amplified by AdCMV.tk/GCV gene therapy system.