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 observe the inhibitory effects of local co-transfection of tissuetype plasminogen activator(tPA) gene and proliferating cell nuclear antigen antisense oligodeoxynucleotides(PCNA-ASODN) on the intima proliferation and restenosis of autograft artery in rabbits. Methods One hundred and twenty male Zelanian rabbits were randomly divided into four groups(n=30, in each group): control group, PCNA-ASODN group, tPA group and tPA+PCNAASODN group. The left and right external iliac arteries (length 1.0 cm) were transplanted reciprocally. The transplanted arteries were respectively soaked in lipofection, PCNAASODN, pBudCE4.1/tPA and pBudCE4.1/tPA+PCNA-ASODN solution about 15 minutes. The transplanted arteries were sutured with 9-0 sutures soaked in PCNA-ASODN and pBudCE4.1/tPA solution. Each group were divided into five subgroups(n=6, in each subgroup) according to the sacrifice time (3 d, 7 d, 14 d, 28 d and 56 d after operation). On every sacrifice time point, the vascular specimens were harvested. The thrombocyte assembling and thrombus forming lining vessel wall were observed by scanning electron microscope. The pathological morphology of transplanted arteries were observed under microscope(HE). The intimal areas and stenosis ratio(%) of transplanted arteries were calculate and analyzed statistically among groups by computer system. The mRNA expression of tPA gene in transplanted ressel wall was detected with vevere transcriptionPCR(RT-PCR). The number of PCNA positive cells in transplanted vessel wall was counted by SP immunochemisty.Results The mRNA expression of tPA gene in the transplanted vessel wall in tPA and tPA+PCNA-ASODN groups was higher than that of the other two groups(P＜0.01).The number of PCNA positive cells in the transplanted arteries in PCNAASODN, tPA and tPA+PCNAASODN groups were significantly lower than that of control group(P＜0.05，P＜0.01). The intimal areas and degrees of luminal stenosis of PCNAASODN, tPA and tPA+PCNAASODN groups were lower than those of control group(P＜0.05，P＜0.01), and those of tPA＋ PCNA-ASODN group were lower than those of PCNA-ASODN and tPA groups(P＜0.05). Scanning electron microscopy showed that there were a few thrombocytes lining the vessel wall of tPA group and tPA+PCNAASODN group and no thrombus, whereas there were abundant thrombocytes and thrombi lining the vessel wall of the control group. Conclusion Co-transfection of tPA gene and PCNA-ASODN can effectively inhibit the proliferation of VSMC, hyperplasia of intima and restenosis of transplanted artery.
Abstract: Objective To investigate the effect of keeping implanted vein graft from restenosis by local application of paclitaxel. Methods Ninetysix New Zealand rabbits were randomly divided into three groups, control group (n=32), group Ⅰ(n=32), group Ⅱ(n=32). The vein graft stenosis model was made in all rabbits. In group Ⅰand group Ⅱ, 1μg and 8μg of paclitaxel was applied locally in pluronic gelatin respectively. There were no local treatment in control group. Grafts were harvested at 1, 2, 4, and 6 weeks and underwent morphological analysis as well as immunohistochemical analysis. Results The intimal thickness in group Ⅱ were significantly decreased compared to those in control group at 1,2,4, and 6 weeks after operation (30.10±4.50μm vs. 48.20±9.16μm, 40.70±6.91μm vs. 54.20±8.67μm, 54.70±7.11μm vs. 68.60±13.72μm, and 68.70±8.24μm vs. 76.40±12.98μm, Plt;0.05). The CD8 positive cells and metallothionein positive cells in group Ⅰand group Ⅱ were significantly decreased compared to those in control group (Plt;0.05). Conclusion The results suggest that perivascular application of paclitaxel inhibits neointimal hyperplasia of vein grafts in a rabbit model, and paclitaxel may have a therapeutic potential for the treatment of vein graft disease.
【Abstract】 Objective To reduce restenosis in vein grafts after coronary artery bypass grafting, to investigate theeffect of human tissue factor pathway inhibitor(TFPI) gene del ivery on neointima formation. Methods The eukaryotic expressed plasmid vector pCMV-(Kozak) TFPI was constructed. Forty-eight Japanese white rabbits were randomly divided into 3 groups with 16 rabbits in each group: TFPI group, empty plasmid control group and empty control group. Animal model of common carotid artery bypass grafting was constructed. Before anastomosis, vein endothel iocytes were transfected with cationic l iposome containing the plasmid pCMV- (Kozak) TFPI (400 μg) by pressurizing infusion (30 min) in TFPI group. In empty plasmid control group, vector pCMV- (Kozak) TFPI was replaced by empty plasmid pCMV (400 μg). In empty control group, those endothel iocytes were not interfered. After operation, vein grafts were harvested at 3 days for immunohistochemical, RTPCR and Western-blot analyses of exogenous gene expression and at 30 days for histopathology measurement of intimal areas, media areas and calculation of intimal/media areas ratio. Luminal diameter and vessel wall thickness were also measured byvessel Doppler ultrasonography and cellular category of neointima was analyzed by transmission electron microscope at 30 days after operation. Results Human TFPI mRNA and protein were detected in TFPI group. The mean luminal diameter of the TFPI group, empty plasmid control group and empty control group was (2.68 ± 0.32) mm, (2.41 ± 0.23) mm and (2.38 ± 0.21) mm respectively. There were statistically significant differences between TFPI group and control groups (P lt; 0.05). The vessel wall thickness of the TFPI group, empty plasmid control group and empty control group was (1.09 ± 0.11) mm, (1.28 ± 0.16) mm and (1.34 ± 0.14) mm respectively. There were statistically significant differences between TFPI group and other control groups (P lt; 0.01). The mean intimal areas, the ratio of the intimal/media areas of the TFPI group were (0.62 ± 0.05) mm2and 0.51 ± 0.08 respectively, which were reduced compared with those of the two control groups(P lt; 0.05). The mean media areas had no significant differences among three groups (P gt; 0.05). Through transmission electron microscope analyses, no smoothmuscle cells were seen in neointima of TFPI group in many visual fields, but smooth muscle cells were found in neointima of two control groups. Conclusion Human TFPI gene transfection reduced intimal thickness in vein grafts.
ObjectiveTo investigate the risk factor for restenosis of esophageal anastomosis stricture after esophageal cancer operation. MethodsWe retrospectively analyzed the clinical data of 83 patients including 61males and 22 females at age of 58.9(41-81) years with esophageal anastomoic stricture after esophageal cancer operation between January 2002 and December 2013. According to whether the patients developed to restenosis or not, the statistical test and logistic regression was conducted to analyze the risk factors for restenosis. ResultsIn the 83 patients with esophageal anastomoic stricture after esophageal cancer surgery, 35 patients (42.2%) experienced restenosis within the following-up of 1 year. The result of logistic regression analysis indicated that restenosis appeared in 3 months (Wald value=23.3, P < 0.001), the interval between two subsequent sessions of more than 4 weeks at each esophagus dilatation(Wald value=4.8, P=0.029) and the stricture diameter of less than 12 mm after dilation (Wald value=5.8, P=0.016) are the independent risk factors for restenosis in esophageal anastomotic stricture. ConclusionFor the patients with esophageal anastomoic stricture after esophageal cancer operation, we believe that it's conducive to reduce esophageal restenosis if the interval between dilations is within 4 weeks and the diameter of stricture after dilation can reach above 12 mm.
Objective To find out the follow-up results of early in-stent restenosis (ISRS) and develop effective way to improve clinical treatment and precaution of restenosis. Methods The data from a registry of 51 consecutive patients who underwent elective carotid artery angioplasty and stenting （CAS） at our institution between Jan. 2003 and Sept. 2005 were retrospectively reviewed. Complete data for 37 of these patients were available. All patients underwent duplex ultrasound scanning in follow-up period, which was used to determine the degree of restenosis. Results CAS was performed in 37 patients， 8.1% (3/37) were women. Mean age was (70.5±5.9) years. Mean time of follow-up was (12.2±7.7) months. Sixteen (43.2%) caces of ISRS （gt;30%） were found by color duplex ultrasound scanning， but only 1 (2.7%) ISRS was found gt;50%; 3 female patients had minor ISRS. Among all factors, female patients had higher incidence of ISRS than male (P=0.038); balloon-expanding after stenting and accompanying with other artherosclerosis of periphery vessel had correlation about ISRS （P=0.037, P=0.016）. Conclusion The severe restenosis rate is acceptable. Female patients were more likely to have ISRS. Balloon-expanding maybe have effect on reducing incidence of ISRS and controlling artherosclerosis was helpful.
Coronary artery bypass grafting (CABG) is a major treatment method for coronary artery disease，but postoperative vein graft restenosis remains an unsolved problem. Research has confirmed that perioperative antiplatelet therapy can effectively reduce early coronary artery bypass graft thrombosis. Lipid-lowering therapy can significantly improve long-term patency of saphenous vein grafts after CABG. In addition，gene therapy provides a new direction to prevent vein graft restenosis after CABG.
ObjectiveTo evaluate the effect of low power red laser illumination on the intimal proliferative response in vein graft models.MethodsAutogenous vein graft models were established in 80 rats by transplanting jugular vein to carotid artery by end to end anastomosis, and were randomized into two groups: control group (graft nonilluminated), laser illumination group (0.9 J/cm2).The grafted veins were harvested at 3,7,14 or 28 day respectively after operation. IH (intimal hyperplasia) and SMC (smooth muscle cell) proliferations were pathologically and immunohistochemically observed and analyzed by computer digitizing system. ResultsThere were no significant differences in the intimal average thickness and the areas of lumen between two groups for 3 day. Laser group was significantly lower than the control in both the intimal average thickness and the stenosis of lumen at 7 day,14 day and 28 day (P＜0.05).Immunohistochemical analysis of PCNA indicate the decreased positive cell in laser group compared with the control group (P＜0.01).ConclusionThese preliminary results demonstrate that a certain density of low power red laser illumination in vein graft inhibits SMC proliferation and neointimal hyperplasia in rat.
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.
ObjectiveTo observe the effects of endovascular radiation (ER) on the proliferation and apoptosis of medial smooth muscle cells (SMC) and to discuss the possible mechanisms of radiation in the prevention of vascular restenosis (RS) in rabbits after carotid endarterectomy (CEA).MethodsForty rabbits undergoing CEA were randomly divided into four groups (each group=10) and given a radiation dose of 0, 10, 20 and 40 Gy 32P respectively. Rabbits were killed on the 3rd, 7th, 14th, 28th and 56th day after operation. The specimens were collected and histopathologic examinations were done.ResultsProliferation apparently occurred in the intima and media of carotid the lumen became narrow in the control group on the 14 th, 28 th and 56 th day after operation. While in the radiation groups, proliferation was apparently suppressed and the lumen was much less narrowed (P＜0.05). The apoptosis rate of SMCs and PCNA positive cells increased on the 3rd day after operation and reached the peak on the 7th day. There was statistical difference between the ER groups and control group (P＜0.01). The effects were much more evident in 20 Gy and 40 Gy groups compared with 10 Gy group (P＜0.01).ConclusionER may prevent RS by suppressing SMC proliferation and migration as well as inducing SMC apoptosis. The effects are positively correlated with radiation doses. SMC proliferation and apoptosis occur in the early period after balloon injury, while hyperplasia of intima and medial happens later.