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 study the expression of receptor of advanced glycation end products (RAGE) in autogenous vein graft of streptozotocin induced diabetic rats and the inhibitory effects of aminoguanidine on intimal hyperplasia. Methods Sixty male Sprague-Dawley rats were randomly divided into three groups: aminoguanidine group, distilled water group and control group. Autogenous vein graft models were established in all groups. Streptozotocin was injected into abdominal cavity to induce diabetes in both aminoguanidine group and distilled water group, and they were intragastric administrated with aminoguanidine or distilled water, respectively before and after transplantation. Specimens were collected from autogenous vein graft 7 days and 14 days after surgery to undergo histological examination. At the same time, the level of serum advanced glycation end products (AGE) was tested. Western blotting and immunohistochemistry were used to detect the protein expression of RAGE and NF-κB p65. RAGE and NF-κB p65 mRNA were measured by reverse transcription-PCR. Results The mRNA and protein expressions of RAGE, NF-κB p65, the level of serum AGE and the intimal thickness of vein graft in distilled water group increased in comparison with those in control group 7 days and 14 days after surgery （P＜0.05). The level of serum AGE, mRNA and protein expressions of NF-κB p65 and the intimal thickness of vein graft in aminoguanidine group were lower than those in distilled water group （P＜0.05), and showed no significant difference compared with control group （P＞0.05). Conclusion The over-expression of RAGE in vein graft activats NF-κB in streptozotocin-induced diabetic rat, which has a close relation with intimal hyperplasia. Aminoguanidine can block the binding of AGE and RAGE by inhibiting the production of AGE, which will prevent intimal hyperplasia of vein graft.
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
Coronary artery bypass grafting (CABG) is an effective method for the treatment of coronary heart disease at present. However, there is still a high rate of vein graft occlusion after CABG, which has a serious impact on the short and long-term clinical results. Venous access technique has been considered as an important factor on affecting the long-term patency rate. Compared with harvesting technology of the open saphenous vein harvesting, no-touch technology retained the surrounding tissue and vascular adventitia of great saphenous vein, and it avoided the high pressure of expansion vein. After CABG was performed by using the no-touch technique, the vein grafts obtained a better short and long-term patency rate, but the effect still needs further clinical verification.
【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.
ObjectiveTo investigate the expression of extracellular signalregulated kinase (ERK) and p38 mitogenactivated protein kinase （p38 MAPK） in autogenous vein grafts during vascular remodeling.MethodsAn autogenous vein graft model was established by transplanting the right jugular vein to infrarenal abdominal aorta in 80 Wistar rats. Vein graft samples were harvested 6 hours, 24 hours, 3 days, 7 days, 2 weeks, 4 weeks, 6 weeks and 8 weeks after surgery. Gene expression of ERK and p38 MAPK was measured by reverse transcriptionPCR. Western blot was used to detect the expression of protein products and phosphorylation protein products of ERK and p38 MAPK. Apoptosis of vascular smooth muscle cells (VSMCs) was determined by TUNEL. Proliferating cell nuclear antigen(PCNA) of VSMCs also was studied.ResultsThe expression of ERK1 mRNA and p38 MAPK mRNA increased considerably after surgery. ERK1 mRNA reached the peak on the 7th day 〔（33.2±14.2）%, P＜0.01〕, but p38 MAPK mRNA reached the peak on the second week after surgery 〔(58.8±26.2）%, P＜0.01〕. The expression of ERK1/2 detected by western blot reached the peak during 1 to 2 weeks and decreased gradually to normal level 6 weeks after surgery. The expression of p38 MAPK reached the peak during 2 to 4 weeks and decreased to 1/4 to 1/2fold 8 weeks after surgery. There was a positive relationship between ERK1 and PCNA(r=0.759 6，P＜0.01) and a positive relationship between p38 MAPK and apoptosis(r=0.892 2，P＜0.01). ConclusionActivation of MAPK system exists in autogenous vein grafts and it may become a new target for the therapy of stenosis after vein grafts.
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.
In order to solve the defect of blood vessel in tissue transplantation and complicated palmar amputation, bridge by "Y" type vein had been used from Jan. 1990 to Jul. 1996. Twenty-three cases were treated. In this series, there were 16 males and 7 females, with ages ranged from 10 to 42 years old. Six cases were the defect of lower legs anterior skin and tibia, 3 cases were the femur fracture with injury of femoral artery and tissue’s defect, 2 cases were defect of five fingers, 12 cases were complicated palmar amputation. RESULT: 15 cases with tissue transplantation and 12 cases with limb replantation were all survival without infection or necrosis. After the following-up for 3 years (ranged from 1 to 5 years), the function of injured limbs were satisfactory, 19 patients had resumed their original work. So, to bridge by "Y" type vein is a good method for repairing the defect of blood vessels in tissue transplantation and complicated palmar amputation, but skilled microsurgery technique is required.
ObjectiveTo evaluate the effect of human heme oxygenase 1 augmentation in vein grafts by adenoviral mediated gene transfer of heme oxygenase 1 (Ad hHO 1) on intimal hyperplasia.MethodsTwenty one Japanese white rabbits were divided into three groups: control group, Ad null control group, and Ad hHO 1 group(each group 7 rabbits). During the operation of rabbits jugular vein into carotid artery interposition grafting, harvested rabbit jugular vein segments were exposed for 30min at room temperature to heparin saline, recombinant replication deficient adenovirus encoding hHO 1(Ad hHO 1, 1× 10 9pfu/ml), and nude recombinant replication deficient adenovirus (Ad null, 1×10 9pfu/ml). Quantitative histological studies of the vein segments were performed 28 days after operation. Protein of hHO 1 was detected with method of immunohistochemical staining(S P) in 14 days and 28 days after operation.ResultsThe average intimal thickness, medial thickness and intimal to medial(I/M) ratio were calculated for each group 28 days after bypass operation. Compared to intimal thickness, I/M ratio of control group veins and Ad null group veins,Ad hHO 1 group veins decreased significantly( P lt;0.01). There was no statistically difference in medial thickness ( P gt;0 05). Strong staining of hHO 1 was detected in vein grafts wall of Ad hHO 1 group.ConclusionAd hHO 1 gene therapy may inhibit intimal hyperplasia of vein grafts in rabbits.
Abstract: Objective To determine the effects of oxidative stress reaction on intima hyperplasia after autologous vein grafting. Methods Seventy female SpragueDawley(SD) rats were randomly divided into a control group(n=10) and an experimental group (n=60). The experimental group was then divided into six time points of one day; one, two, four, and six weeks; and two months after surgery; with 10 rats for each time point. Autologous vein grafting models were established. At each time point the designated rats were anaesthetized, and the grafts were isolated and stained with HE. The same length of external jugular vein was cut from each rat in the control group. The neointima to tunica media area ratios (I/M) were measured with acomputerized digital image analysis system. Nuclear factorkappa B (NF-κB) and copper zinc superoxide dismutase (CuZnSOD) were detected byimmunohistochemistry. The concentration of malondialdehyde (MDA) in serum was analyzed by colorimetry. Results In the control group, expression levels of NF-κB and CuZnSOD were low. In the experimental group, expression of NF-κB increased after the operation and peaked two weeks later. The plateau was sustained for about one month, and then the level of expression declined gradually, reaching the baseline at the twomonth time point. The expression of CuZnSOD increased gradually after the operation and peaked one week later, then declined to the normal level after 2-3 weeks at the plateau. In the control group, the concentration of serum MDA was 4.966±1.346 nmol/ml. In the experimental -group, the-MDA concentration increased dramatically after the operation, then-declined from its highest level at the oneday time point (21.161±2.174 nmol/ml) to the normal level at two months (6.208±2.908 nmol/ml) after the operation (P＜0.05). In the control group, I/M was 0.2096±0.0253, while in the experimental group, it was higher one week after the operation (0.6806±0.0737) and peaked at four weeks (1.4527±0.0824), falling to 1.0353±00656 at six weeks and 0.9583±0.0516 attwo months (P＜0.05) for the experimental and control groups). Conclusion Endothelial cell injury initiates an oxidative stress reaction after autologous vein grafting and augments inflammation by activating NF-κB, thus playing an important role in inducing restenosis of the grafted vein.