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The most serious problem facing the implantation of vascular graft in the body is the formation of blood clots. In order to solve this problem, various attempts have been made by the scientific community for many years. However, endothelialization is the fundamental method to solve thrombosis and keep vascular graft open for a long time. Poly （ε-caprolactone） (PCL) has the advantages of biodegradability, low cost and good mechanical properties. In recent years, it has been widely used as tissue engineering scaffolds, drug deliverys and so on. This article mainly reviews the endothelialization of small-caliber vascular graft based on PCL after implanted in different animal models, as well as the endothelialization of the same animal model but under different implantation conditions, and trying to find the reasons why small-caliber vascular grafts are still not ideal in clinical applications at different angles such as the different animal models and the different way about endothelialization, and provide references for future animal model selection.
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BACKGROUND: In the research of tissue engineering, there are inevitably various kinds of microorganisms attached to animal tissues, and asepsis is a basic requirement of clinical application of tissue engineering materials. OBJECTIVE: To investigate the effect of 75% ethanol sterilization on the properties and biocompatibility of bovine pericardium. METHODS: Bovine pericardial tissue was sterilized with sterile PBS (control group), PBS containing 1% antibiotic (penicillin/streptomycin/ amphotericin B solution), chlorhexidine and 75% ethanol. LB solid medium was used to evaluate the bactericidal effect of four methods. VB staining was used to evaluate the effect of four sterilization treatments on the tissue structure of bovine pericardium. The cytotoxicity of four sterilized extracts was determined by the CCK-8 assay. The bovine pericardium was sterilized with 75% ethanol and then used to make acellular scaffold, which was co-cultured with human umbilical vein endothelial cells to observe the effect of cell adhesion and endothelialization. RESULTS AND CONCLUSION: (1) The bovine pericardium treated with 75% ethanol and chlorhexidine for 24 hours met the requirements of complete sterilization, and significant colony formation was observed in 1% antibiotic-treated and control groups. (2) VB staining revealed that the collagen fibers of bovine pericardium treated with 75% ethanol, chlorhexidine and 1% antibiotic were arranged in wavy pattern, with compact structure, less elastic fiber content but clear structure.(3) Bovine pericardium treated with 75% ethanol did not affect the proliferation activity of L929 cells, and the cell survival rate within 1-3 days was more than 100%. Chlorhexidine-sterilized bovine pericardium had strong cytotoxicity, leading to cell death. (4) Human umbilical vein endothelial cells grew and adhered normally on the surface of acellular scaffold. During the 20-day implantation period, the highest number of cells adhering to acellular scaffold appeared on days 8-12. These results suggest that 75% ethanol could effectively eliminate all microorganisms attached to the bovine pericardium without affecting the histological integrity and biocompatibility.
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Objective To investigate the role and mechanism of regulatory T cells (Treg cell) in promoting endothelialization of carotid artery after balloon injury. Methods Treg cells were isolated from rat spleen by Treg cell sorting kit and carotid artery injury model was established. The rats were divided into three groups: control group (the same volume of normal saline), vascular endothelial growth factor (VEGF) group (intravenous injection of VEGF, 20 μmol/kg) and Treg cell group (1×105 Treg cells injected via tail vein). HE staining and immunohistochemistry were used to detect endothelialization. The levels of interleukin (IL)-10, transforming growth factor β(TGF-β), IL-1β and tumor necrosis factor α (TNF-α)in serum were detected by ELISA. Flow cytometry was used to detect the proportion of monocytes, T cells and endothelial progenitor cells (EPC). Results Histological staining showed that no endothelial cells were observed in the control group, and more endothelial cells were found in the carotid intima in the Treg cell group. The result of immunohistochemistry showed that the expression of IL-10, TGF- β, IL-1 β and TNF-α protein in the control group and the Treg cell group were significantly different (t = 8.252, P0. 05). The proportion of EPC in TGF-β blocking group was(0. 3082±0. 02291)%, compared with the Treg cell group, the difference was significant (t = 4. 029, P<0. 01). Conclusion Treg cells promote the rapid endothelialization of carotid artery after balloon injury by inducing EPC mobilization.
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Due to limited availability of autologous blood vessels (blood vessels from the same recipient used for vascular transplantation materials) and inadequate growth ability of non-autologous blood vessels (artificial blood vessel transplantation materials), more and more attention has been paid to tissue engineering blood vessels. In this study, we constructed an ammonium phosphate zwitterion modified acellular vascular scaffold with highly biocompatible bone marrow-derived endothelial progenitor cells as the inner layer of a new vascular transplantation material. The vascular acellular scaffolds were modified by a simple method-co-precipitation method. The platelet adhesion test, hemolysis test, recalcification test and cytotoxicity of acellular vascular scaffolds in vitro were evaluated. Ammonium phosphate zwitterions modified endothelial progenitor cells on the surface of acellular scaffolds with concave and convex structure on the surface of natural vascular lumen can be effectively promoted by improving anticoagulant activity. Modified acellular scaffolds have similar mechanical properties to natural blood vessels and can effectively construct endothelialization in vitro. The results of this study provide a preliminary exploration for the modification of vascular acellular scaffolds to achieve anti-thrombosis and endothelialization in vitro.
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Humans , Blood Vessel Prosthesis , Phosphates , Thrombosis , Tissue Engineering , Tissue ScaffoldsABSTRACT
AIM:To study the effect of crocin on the mobilization of endothelial progenitor cells (EPCs) in the peripheral blood of the mice with carotid arterial injury and its mechanism.METHODS:The carotid artery injury model of the C57BL/6 mice was established by the method of wire injury.The animals were divided into sham operation group,saline-treated model group,and low dose,medium dose and high dose (10,50 and 100 μ mol· kg-1 · L-1,respectively) of crocin treatment groups.The mobilization of the EPCs in peripheral blood of the mice with carotid artery injury was detected by flow cytometry at 3 d.The changes of vascular endothelial growth factor (VEGF),stromal-derived factor-1 (SDF-1),basic fibroblast growth factor (bFGF),epidermal growth factor (EGF) and matrix metalloproteinase-9 (MMP-9) in the peripheral blood of the mice with carotid artery injury were detected by enzyme-linked immunosorbent assay at 7 d.The vascular re-endothelialization and intimal hyperplasia of the mice with carotid artery injury were detected by Evans blue and hematoxylin-eosin staining.At the same time,real-time PCR was used to detect the mRNA expression of vascular repair factor-related receptors,vascular endothelial growth factor receotor-2 (VEGFR-2),CXC chemokine receptor-4 (CXCR4),basic fibroblast growth factor receptor (bFGFR) and epidermal growth factor receptor (EGFR),in the injured segments of carotid arteries.RESULTS:Compared with sham group,the EPCs mobilization and the content of vascular repair factors VEGF,SDF-1,bFGF,EGF and MMP-9 in peripheral blood were increased in model group (P ＜0.05).The area of vascular endothelium was decreased,while the area of intimal hyperplasia and the ratio of intimal to medial membrane area were increased significantly (P ＜ 0.05).The expression levels of VEGFR-2,CXCR4,bFGFR and EGFR were also increased in the injured segments of carotid arteries (P ＜ 0.05).Compared with model group,the EPCs mobilization and the content of vascular repair factors VEGF,SDF-1,bFGF,EGF and MMP-9 in peripheral blood were significantly increased in different concentrations of crocin-treated mice with carotid artery injury (P ＜ 0.05).The area of vascular endothelium was gradually increased,while the area of intimal hyperplasia and the ratio of intimal to medial membrane area were gradually decreased (P ＜ 0.05).The expression levels of VEGFR-2,CXCR4,bFGFR and EGFR were also gradually increased in the injured segments of cartid arteries (P ＜ 0.05).CONCLUSION:Crocin promotes the mobilization of EPCs and the re-endothelialization of damaged blood vessels in the mice with carotid artery injury,thus repairing the injured vasculature.
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AIM:To study the effect of crocin on the mobilization of endothelial progenitor cells (EPCs) in the peripheral blood of the mice with carotid arterial injury and its mechanism.METHODS:The carotid artery injury model of the C57BL/6 mice was established by the method of wire injury.The animals were divided into sham operation group,saline-treated model group,and low dose,medium dose and high dose (10,50 and 100 μ mol· kg-1 · L-1,respectively) of crocin treatment groups.The mobilization of the EPCs in peripheral blood of the mice with carotid artery injury was detected by flow cytometry at 3 d.The changes of vascular endothelial growth factor (VEGF),stromal-derived factor-1 (SDF-1),basic fibroblast growth factor (bFGF),epidermal growth factor (EGF) and matrix metalloproteinase-9 (MMP-9) in the peripheral blood of the mice with carotid artery injury were detected by enzyme-linked immunosorbent assay at 7 d.The vascular re-endothelialization and intimal hyperplasia of the mice with carotid artery injury were detected by Evans blue and hematoxylin-eosin staining.At the same time,real-time PCR was used to detect the mRNA expression of vascular repair factor-related receptors,vascular endothelial growth factor receotor-2 (VEGFR-2),CXC chemokine receptor-4 (CXCR4),basic fibroblast growth factor receptor (bFGFR) and epidermal growth factor receptor (EGFR),in the injured segments of carotid arteries.RESULTS:Compared with sham group,the EPCs mobilization and the content of vascular repair factors VEGF,SDF-1,bFGF,EGF and MMP-9 in peripheral blood were increased in model group (P ＜0.05).The area of vascular endothelium was decreased,while the area of intimal hyperplasia and the ratio of intimal to medial membrane area were increased significantly (P ＜ 0.05).The expression levels of VEGFR-2,CXCR4,bFGFR and EGFR were also increased in the injured segments of carotid arteries (P ＜ 0.05).Compared with model group,the EPCs mobilization and the content of vascular repair factors VEGF,SDF-1,bFGF,EGF and MMP-9 in peripheral blood were significantly increased in different concentrations of crocin-treated mice with carotid artery injury (P ＜ 0.05).The area of vascular endothelium was gradually increased,while the area of intimal hyperplasia and the ratio of intimal to medial membrane area were gradually decreased (P ＜ 0.05).The expression levels of VEGFR-2,CXCR4,bFGFR and EGFR were also gradually increased in the injured segments of cartid arteries (P ＜ 0.05).CONCLUSION:Crocin promotes the mobilization of EPCs and the re-endothelialization of damaged blood vessels in the mice with carotid artery injury,thus repairing the injured vasculature.
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Objective To evaluate the feasibility, efficacy and safety of new nano material occluder of single rivet type (left-disk with no-hub) in treating ventricular septal defect (VSD) in order to provide experimental basis for clinical application. Methods A total of 26 healthy adult dogs were selected for this study . Under thoracotomy , VSD model was established through fluoroscopically-guided percutaneous puncturing of the right ventricular free wall. The models were randomly and equally divided into the study group(n=13, using nano material VSD occluder) and the control group(n=13, using double-hub nitinol occluder). Every two dogs from each group were sacrificed each time at one, 2, and 3 months after percutaneous closure of VSD with corresponding occluder, the tissue samples were collected and sent for gross examination as well as for the optical and electronic microscopy study;the blood concentration of nickel ion was also determined. The state of endothelialization after implantation of the new type occluder was evaluated, and the complications such as residual shunt and superficial thrombus formation were recorded. The results were analyzed. Results By open chest operation with small incision and percutaneous puncturing of the right ventricular free wall, VSD model was successfully established in all 26 dogs. The success rate of the implantation of the VSD occluder in the study group was 100%, while it was 91.7% in the control group. One, 2, 3 and 6 months after the implantation, the heart specimens of 25 dogs were removed and gross examination showed that neither occluder displacement nor alloy wire fracture occurred in both groups. No thrombus formation or vegetation attached on the disk surface was observed. One month after the procedure , in the study group the bilateral disk surfaces of the occluder were covered with thin layer transparent tissue , which were proved to be composed of the fibrous tissue and endothelial cells through pathologic and electronic microscopy study. Six months after implantation, the superficial tissue of the occluder became further thickened and the occluder edge became fused with the surrounding heart tissue. Conclusion The design of the new VSD nano materials occluder, which has a left-disk with no hub, is very scientific. Compared with double-hub nitinol occluder, the new device can shorten the time of complete endothelialization and effectively occlude the VSD. Therefore, this new nano material occluder has promising prospect in clinical application.
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<p><b>OBJECTIVE</b>To study the safety of the novel high nitrogen nickel-free austenitic stainless steel bare metal stents (BMS) in a recognized porcine coronary model and to select a better grid structure of it.</p><p><b>METHODS</b>Three types of stents were randomly implanted in different coronary arteries of the same pig: 316 L stainless steel BMS (316 L-BMS) (n=12), novel high nitrogen nickel-free stents Grid A (NF-A-BMS) (n=12) and novel high nitrogen nickel-free stents Grid B (NF-B-BMS) (n=12). In total, eighteen animals underwent successful random placement of 36 oversized stents in the coronary arteries. Coronary angiography was performed after 36 d of stents implantation. Nine animals were respectively sacrificed after 14 d and 36 d for histomorphologic analysis.</p><p><b>RESULTS</b>Quantitative coronary angiography (QCA) showed similar luminal loss (LL) in the three groups: (0.21 ± 0.17) mm for 316 L-BMS, (0.16 ± 0.12) mm for NF-A-BMS, (0.24 ± 0.15) mm for NF-B-BMS (P>0.05). Histomorphomeric analysis after 15 d and 36 d revealed that there was also no significant difference among the three groups in neointimal area (NA) with similar injury scores respectively. High magnification histomorphologic examination showed similar inflammation scores in the three groups, but NF-A-BMS group had poorer endothelialization scores compared with NF-B-BMS group, 2.00 ± 0.63 vs. 2.83 ± 0.41 (P=0.015) at 15 d, which also could be proved by the scanning electron microscope. However, the difference could not been observed at 36 d.</p><p><b>CONCLUSION</b>The novel NF-BMS showed similar safety as 316 L-BMS during the short-term study. NF-B-BMS had better endothelialization than NF-A-BMS and this may owe to the specific strut units.</p>
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Animals , Coronary Vessels , Nickel , Nitrogen , Random Allocation , Stainless Steel , Chemistry , Stents , Swine , Swine, MiniatureABSTRACT
Objective To construct a sirolimus loaded drug-eluting stent (DES) using chitosan/heparin coating membrane and to explore its effect on anticoagulation and early re-endothelialization in porcine coronary artery. Methods Chitosan/heparin layer-by-layer self-assembly coating was applied to sirolimus DES, and the asymmetric applicator was used to allow for the stent blood surface to be chitosan/heparin coated and the stent vascular surface to be polylactic acid (PLA)--irolimus. The experiment was divided into bare metal stent (BMS) group, chitosan/heparin stent group, sirolimus DES group and chitosan/heparin sirolimus DES group. The anticoagulation effect of chitosan/heparin sirolimus DES was tested by arteriovenous shunt model and high load thrombosis model. The effect of chitosan/heparin sirolimus DES on early re-endothelialization was tested by 1-week long balloon injury to porcine coronary artery. Results No thrombus was found on the surfaces of chitosan/heparin sirolimus DES and chitosan/heparin stent in the arteriovenous shunt model, while the surfaces of BMS and sirolimus DES were covered with thrombus. No stent thrombosiswas found in the high load thrombosis model test of chitosan/heparin sirolimusDES and chitosan/heparin stent within 6 hours, and stent thrombosis was found in BMS at (59. 0±8. 5) min and in sirolimus DES at (67. 0 ±7. 8) min (P<0. 01). Theearly re-endothelialization test showed endothelial coverage rates of chitosan/heparin sirolimus DES and chitosan/heparin stent after 7 d implantation were (82. 7± 16. 4) % and (80. 7 ± 14. 1) %, significantly higher than those of BMS and sirolimus DES ([64. 3±11]% and [59. 8±8. 4]%, respectively; P<0. 01). Conclusion Chitosan/ heparin-coated-sirolimus DES has satisfactory anticoagulation property and it can accelerate early re-endothelialization.
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The purpose of our study was to create a novel rat aorta stent implantation model. Stainless steel bare metal stents (BMS) or paclitaxel-eluting stents (PES) were implanted in male Sprague-Dawley rats (BW 400 +/- 20 g). Two and four weeks after stent implantation, the aorta were collected, fixed with 2% glutaraldehyde, and cut into two segments. One segment was used for scanning electron microscopy analysis to evaluate re-endothelialization, and the other segment was used to calculate the neointimal area. At 2 weeks after stenting, the appearance of neointimal hyperplasia was less in the PES group than in the BMS group. At 4 weeks after stenting, no significant difference in neointimal hyperplasia was observed between two groups. On the other hand, the PES group showed more thrombus formation and less re-endothelialization compared to the BMS group. This study demonstrated the ability of a novel rat model of aorta stenting via a common carotid artery to measure the efficacy and safety of commercially available drug-eluting stents.
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Animals , Male , Rats , Angioplasty/methods , Aorta, Thoracic/surgery , Coronary Artery Disease/surgery , Drug-Eluting Stents , Histocytochemistry , Microscopy, Electron, Scanning , Models, Animal , Neointima/pathology , Paclitaxel/administration & dosage , Rats, Sprague-DawleyABSTRACT
The application of covered stent in vascular malformation such as aneurysm,pseudoneurysm(PSA) ,arteriovenous fistula(AVF) has outcome to an encouraging result.Recently,it has also been effectively used for PTA,TIPS,traumatic lesions of peripheral vessels,and pseudoneurysm of dialysis grafts,etc.But there still remain some issues on the restenosis and endothelialization after the performance with covered stent.This review will pay attention to them.
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50%) of the stent at 2 weeks follow-up,so did 3 cases at 12 weeks follow-up,and the total stenosis rate was 37.5% and 5 cases manifested full endothelialization(3 different locations of the sample all manifested full endothelialization) ,3 cased manifested partial endothelialization(at least 1 location of the sample didn't show full endothelialization) ,and the two terminal parts were easier to get endothelialization than the central part.Before and after the stent implantation,hepatic function of all cases didn't demonstrate any obvious changes.Conclusions Balloon-expandable covered stent can be implanted in canine hepatic artery successfully,with good apposition ability,full endothelialization,and no influence on hepatic function.
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Objective To evaluate the endothelialization of Chinese nitinol atrial septal defect occlud-er device. Methods Atrial septal defect with controllable size was created by the Brockenborough needle and Rashkind balloon atrial septostomy, the occluder devices were implanted in six piglets (mean weight 7. 5 kg). Two pigs were killed each time after 1 month, 3 months and 6 months after the device implantation and then the explanted devices were examined by scanning electron microscope (SEM). Results The devices were found covering with collagen fibrosis together with diffuse endothelial cells spreading over the primer 1 month after implantation. The implants were covered mostly by ncointima 3 months after implantation and completely covered by confluent endothelial cells 6 months after the implantation. Endothelial cells were not found on the smooth marker band at 3 months, however, did exist by 6 months. Conclusions Home-made atriatseptal defect occluder devices were mostly endothelialised 3 months after the implantation and did completely at 6months.
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GDC embolization has been performed selectively since 1991 in patients with intracranial aneurysms and made remarkable technical and clinical advances in recent years. But until now, this procedure lacks an adequate long-term follow-up study. Also, clear mechanism and evidence of electrothrombosis and endothelialization of aneurysm neck, the incidence of vasospasm after GDC embolization are still controversial. Here we critically reviewed the published literatures pertaining to the GDC embolization in order to gain a comprehensive understanding and knowledge of forementioned controversies. Also from November 1997 to April 1999, we treated 12 patients of intracranial aneurysms with GDC embolization. In conclusion, although certain shortcomings and controversies are still remain, the GDC embolization can be an alternative, supportive and attractive therapeutic modality in the treatment of intracranial aneurysms. Not only to improve outcome of intracranial aneurysms but also fulfill the patient's requirement, we need cooperations and cross-training with the interventional neuroradiology and rigorous academic evaluation on anatomy of cerebral vasculature and pathophysiology of cerebrovascular disorders.
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Humans , Aneurysm , Cerebrovascular Disorders , Embolization, Therapeutic , Follow-Up Studies , Incidence , Intracranial Aneurysm , NeckABSTRACT
Objective:To investigate the effect and its possible mechanism of peripheral blood mesenchymal stem cells(MSCs)on endothelium repair in Rabbits with balloon-induced injury carotid.Methods:Purified MSCs were Obtained from peripheral blood through combining density gradient centrifugation with repeating adherence cultivation after the application of Granulocyte colony-stimulating factor(G-CSF)for 5 days in rabbits with atherosclerosis stenosis carotid artery,and marked with enhanced green fluorescent protein(EGFP).EGFP marked MSCs were transplanted into the rabbits in the transplantation of MSCs groups and equivalence culture solution was injected in the control groups through surrounding ears veins after balloon-induced carotid artery in rabbits.The specimens of carotid artery were harvested to use for the analysis of vessels morphology and endothelialization in 7,14,28 days of post-operative,and the homing MSCs were identified.Results:Carotid artery morphology analysis in each stage indicates that intima hyperplasia is obviously less in the transplantation of MSCs groups than that in the control groups(P
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Objective To determine an optimal method of in vivo endothelialization when homograft valve (HV) leaflets are treated with different methods. Methods Twenty five fresh HV leaflets were divided into five groups randomly. The leaflets of GroupⅠ were fresh HV ones without any treatment; GroupⅡwere cryopreserved in liquid nitrogen for 1 month; Group Ⅲ was treated by DOA; GroupⅣ was treated by 25 g?L -1 glutaraldehyde; Group Ⅴ was first treated by hypotonic/hypertonic, then with an enzyme-based solution. Each HV leaflet was trimmed to 2 mm one which was cultured with lymphocyte from the recipient. In order to compare the antigenicity of HV leaflets, 3H-TdR incorporation was observed after tissue-cell coculture and stimulous index (SI) was calculated. The HV leaflets of different groups were implanted into the sheep's femorofemoropopliteal for three months; then the following procedures were done. Immunohistochemistry of Ⅷ factor correlative antigen was used to identify the cells property; observation of growth condition of EC and superficial morphosis of HV leaflets was made with scanning election microscope (SEM). Results Multiple comparison showed that SI of Groups Ⅱ, Ⅲ, Ⅳ, and Ⅴ differed significantly from Group Ⅰ(P0.05), but Group Ⅲ, Ⅳ, and Ⅴ all had significant differences from GroupⅡ (P