姜黄素/聚乳酸—乙醇酸共聚物复合薄膜的制备及抗凝血研究

血管支架内再狭窄是血管支架临床应用中最突出的问题,药物洗脱支架的问世成为冠心病介入治疗的一个重要里程碑。但是目前的药物洗脱支架还存在抗凝血不足的问题,药物洗脱支架植入晚期血栓形成的病例在临床上有所报道。姜黄素具有抗增生以及抗凝血等多种药理活性,有望成为药物洗脱支架的新颖药物。我们以可降解高分子材料聚乳酸-乙醇酸共聚物(PLGA)为载体分别制备了三种浓度(3wt%、5wt%、8wt%)的姜黄素复合薄膜。采用傅立叶变换红外光谱研究了复合薄膜的组成成分,结果显示:姜黄素与PLGA的特征峰在复合薄膜的红外图谱中均有出现;体外血小板黏附实验结果显示姜黄素复合薄膜表面的血小板黏附数量减少,较少团聚、变形和激活;复合薄膜的部分凝血活酶时间(APTT)长于纯PLGA薄膜的APTT,这都表明姜黄素/聚乳酸-乙醇酸共聚物复合薄膜的抗凝血性能得到改善,且复合薄膜的抗凝血性能在实验药物浓度范围内随着药物含量的增加,材料的抗凝血性能进一步提高。     

含姜黄素的(丙交酯-乙交酯)共聚物薄膜对血管平滑肌细胞增殖的影响

血管支架内再狭窄一直是困扰经皮冠状动脉介入治疗的主要问题,药物洗脱支架的临床应用显著降低了术后再狭窄率而成为冠心病介入治疗新的里程碑.由于姜黄素具有抗炎和抗增生等药理活性而有望应用于药物洗脱支架.本文采用四唑蓝比色法测定了大鼠血管平滑肌细胞对不同浓度姜黄素的药物敏感性,实验结果表明,姜黄素的浓度范围为2.5～10 μg/ml时,对平滑肌细胞的抑制率大于80%.再以可降解高分子材料丙交酯-乙交酯共聚物(poly (lactic acid-co-glycol acid),PLGA)为载体分别制备了三种姜黄素浓度(3wt%,5wt%,8wt%)的复合薄膜.乳酸脱氢酶的释放检测结果显示这三种载药薄膜对平滑肌细胞没有急性的毒性反应.采用Alamar Blue法分别研究了三种浓度含姜黄素的PLGA薄膜和平滑肌细胞经3 d和7 d共培养后的细胞活性,表明三种浓度的含姜黄素薄膜均能够显著抑制平滑肌细胞增殖,尤其当薄膜中姜黄素浓度为8wt%时,细胞活性值最低,抑制作用最明显.     

聚乳酸-乙醇酸共聚物/羟基磷灰石复合支架修复喉软骨缺损

背景：喉软骨缺损传统的修复方法受到供体来源、排斥反应等限制,因而难以推广。 目的：观察聚乳酸-乙醇酸共聚物/羟基磷灰石复合支架修复喉软骨缺损的效果。 方法：将20只Wistar 大鼠随机分为聚乳酸-乙醇酸共聚物/羟基磷灰石复合支架组和聚乳酸-乙醇酸共聚物支架组,建立喉软骨缺损模型后分别采用聚乳酸-乙醇酸共聚物/羟基磷灰石复合支架和聚乳酸-乙醇酸共聚物支架修复。 结果与结论：聚乳酸-乙醇酸共聚物/羟基磷灰石复合支架组大鼠造模后3,5,7 d时喉骨缺损直径显著小于聚乳酸-乙醇酸共聚物支架组;聚乳酸-乙醇酸共聚物/羟基磷灰石复合支架组大鼠喉软骨缺损部位基本修复,表面平整,且与周围其他组织之间没有明显界限;而聚乳酸-乙醇酸共聚物支架组大鼠喉软骨缺损部位存在凹陷,表面粗糙,和周围组织存在明显界限。说明聚乳酸-乙醇酸共聚物/羟基磷灰石复合支架能够促进喉软骨缺损部位修复,修复喉软骨缺损的效果更理想。  中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

三维支架材料与脂肪干细胞的生物相容性

背景：构建组织工程化气管需要适合的三维支架。 目的：观察脂肪干细胞与聚乳酸-乙醇酸共聚物及聚三亚甲基碳酸酯共聚物支架的生物相容性。 方法：采用组织块法原代分离培养SD大鼠脂肪干细胞,行流式细胞术及多向分化能力鉴定。将脂肪干细胞分别种植于聚乳酸-乙醇酸共聚物和聚乳酸-乙醇酸-三亚甲基碳酸酯共聚物支架中,扫描电镜观察细胞与支架的生物相容性。 结果与结论：脂肪干细胞种植于两种支架材料后生长速度快,扫描电镜观察可见脂肪干细胞呈球型,并伸展形成伪足,贴附于支架材料,细胞间相互连接成团。说明聚乳酸-乙醇酸共聚物与聚三亚甲基碳酸酯共聚物支架均具有良好的生物相容性,无细胞毒性,其多孔的三维立体状结构适合脂肪干细胞黏附生长。     

Mg-PLGA-rhbFGF复合支架在下肢缺血血运重建中的应用研究

目的 制备荷载生长因子的镁合金-聚乳酸-聚乙醇酸共聚物(Mg-PLGA)复合支架,构建大鼠下肢缺血模型,观察其对缺血骨骼肌血管新生的作用与效果.方法 在金属Mg支架表面涂覆包载重组人碱性成纤维细胞生长因子(rhbFGF)的生物降解性PLGA聚合物,制得药物涂层支架(Mg-PLGA-rhbFGF).体外试验研究支架中药物的释放性能.体内试验构建大鼠下肢缺血模型,机械打孔后植入支架,通过检测Mg2+在大鼠缺血骨骼肌、血浆、尿液和大便中的浓度,分析支架中的金属Mg在大鼠体内的降解与代谢情况;通过免疫组化分析支架对大鼠缺血下肢骨骼肌血管新生的作用.结果 在体外试验中,药物在Mg-PLGA药物涂层支架中具有良好的缓释性能,可持续释放4周.在体内试验中,大鼠血液、尿液和大便中的Mg2+度在正常范围内;免疫组化染色及血管密度定量分析表明,药物涂层支架组与空白支架组相比新生血管显著增多、血管壁增厚.结论 载rhbFGF的Mg-PLGA药物涂层支架可促进下肢缺血大鼠缺血骨骼肌血管新生,为危重症下肢缺血性疾病的治疗提供理论基础.     

rhBMP-2／PLGA缓释支架的制备及对MSCs细胞成骨活性的体外研究

目的探讨骨形态发生蛋白（rhBMP-2）的聚乳酸聚乙醇酸共聚物（PLGA）体外缓释生物支架对人骨髓间充质干细胞（MSCs）细胞的影响。方法采用粒子沥滤-冷冻干燥复合工艺制备了附载rhBMP-2的PLGA生物支架,并检测了在PLGA的降解过程中rhBMP-2的释药规律;同时分离培养人骨髓间充质干细胞,体外培养后分别接种于附载和未附载rhBMP-2的PLGA支架上。扫描电镜观察不同时间段MSC在支架上的生长情况;MTT法测定细胞增殖情况。结果rhBMP-2能被包裹进PLGA支架中,而且可以在PLGA支架降解过程中持续释放出来并诱导骨发生。结论骨形态发生蛋白的PLGA复合载体是一种较为理想的新型生物支架。     

生物可降解材料PLGA90/10的体外降解特性及生物相容性

研究生物可降解材料聚乳酸乙醇酸共聚物(PLGA 90/10)的体外降解特性,通过测量材料在体外降解过程中的重量损失并在扫描电镜下观察形态学变化,评估体外降解特性,该实验是在37℃ pH为7.4的磷酸盐缓冲液中进行的.为研究材料的细胞毒性,将小牛血管平滑肌细胞种植在PLGA膜片上,在显微镜下观察细胞生长情况,并通过MTT法测定细胞活性.研究发现结晶型的PLGA90/10显示出表面降解的特性,高分子量的PLGA90/10在开始的4个月内降解缓慢,120天时重量仅损失10%,120天后迅速降解.MTT 法检测细胞增殖指数,与对照组差异无显著意义.这为局部药物治疗工具提供了基础研究.     

聚乳酸－乙醇酸共聚物合成与降解

本文对聚乳酸-乙醇酸(PLGA)的合成制备的多种方法进行了阐述,对聚乳酸-乙醇酸(PLGA)的降解性能和降解机理进行了概述.     

大鼠骨髓间充质干细胞与PLGA构建组织工程脂肪的实验研究

目的探讨采用聚乳酸一聚乙醇酸共聚物（PLGA）生物支架及骨髓间充质干细胞，构建组织工程化脂肪组织的可行性。方法将雄性大鼠骨髓间充质干细胞接种于PLGA支架上，成脂诱导培养1周，扫描电镜观察细胞在支架上的生长及黏附情况；同时，将细胞一支架复合体异体移植于雌性大鼠体内，观察其成脂情况，并使用原位杂交技术鉴定。结果在生物支架上大量成脂细胞呈簇状生长；1个月时可见脂肪组织形成，3个月时脂肪组织成熟。结论PLGA生物支架是一种理想的生物可降解支架，骨髓间充质干细胞接种于PLGA生物支架可用于组织工程化脂肪的研究。     

PLGA缓释材料在骨组织工程研究中的应用

聚乳酸聚乙醇酸共聚物(poly lactic-co-glycolic acid,PLGA)缓释材料以其具有良好的生物相容性、可控的孔径和孔隙率、体内降解时间与骨骼自身修复时间相仿、可以附载生长因子等优点,逐渐成为骨组织工程领域研究的热点。综述了PLGA缓释材料的研究进展,指出目前面临的主要问题是如何使材料更好适应骨生长以及材料中生长因子如何使用这两个方面,认为可缓释多种生长因子的PLGA缓释材料将会成为骨组织工程学研究的重点。     

In vitro studies of platelet adhesion, activation, and protein adsorption on curcumin-eluting biodegradable stent materials

A major complication of coronary stenting is in-stent restenosis (ISR) due to thrombus formation. We hypothesized that locally released curcumin from coronary stent surface would inhibit ISR due to thrombus formation because of antithrombosis of curcumin. In the present work, curcumin-eluting polylactic acid-co-glycolic acid (PLGA) films were fabricated and their properties in vitro were investigated. The in vitro platelet adhesion and activation, as well as protein adsorption on curcumin-loading PLGA films were investigated to evaluate the blood compatibility of curcumin-eluting films. The structure of curcumin-eluting PLGA film and control was examined by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy indicating that the peaks of curcumin did not shift in curcumin-eluting films. The results of contact angle and surface free energy indicated that loading curcumin in PLGA would make PLGA become more hydrophilic, which contributed to the increase of polar fraction of surface free energy. With the increase of curcumin in films, platelets adhering to the curcumin-eluting films decreased significantly. The number of activation platelets decreased after incorporating curcumin in PLGA films. Loading curcumin in PLGA film can markedly reduce the fibrinogen adsorption. All results indicated that incorporating curcumin in PLGA film can improve the blood compatibility of PLGA films. It can be used to fabricate drug-eluting stent to prevent thrombosis formation.     

Curcumin-loaded into PLGA nanoparticles

The incorporation of the curcumin into poly(lactic-co-glycolic)acid (PLGA) nanospheres by the nanoprecipitation technique, the characterization of the nanoparticles and the schistosomicidal activity of the curcumin-loaded into PLGA nanospheres were reported. The incorporation process occurred with high efficiency and the images of field-emission scanning electron microscopy (FESEM) revealed the production of spherically shaped particles. According to the dynamic light scattering measurements, the particles are nanometric and monodisperse. The curcumin-loaded PLGA nanoparticles (50 and 100 μM) caused the death of all worms and a separation between 50% and 100% of Schistosoma mansoni couples at concentrations from 30 μM. Moreover, the curcumin-loaded PLGA nanoparticles also decreased the motor activity and caused partial alterations in the tegument of adult worms. This study marks the first time that schistosomicidal activity has been reported for curcumin-loaded PLGA nanoparticles.     

药物洗脱冠状动脉支架系统动物实验研究

目的通过观察在猪动脉中置人心畅可降解聚合物涂层药物洗脱冠状动脉支架（天津百畅公司开发）及对照组支架后的植入后管腔丢失、内皮化、炎症反应、损伤及血栓形成情况来评价国产可降解聚合物涂层药物洗脱支架临床应用的可行性。方法将2种共60枚支架分别置入30头猪冠状动脉的前降支、回旋支以及右冠状动脉。支架植入后的2,5,12,25周,将不同数量的猪处死行组织形态学检查,观察炎症、血栓形成情况和内皮化评价。结果支架置入术后的冠脉通畅,无明显狭窄;支架贴血管内壁良好,血管内腔表面光滑;2种支架均无血栓形成,心畅可降解聚合物涂层药物洗脱支架炎症反应及内皮化与对照组无明显差异,其管腔丢失较对照组轻或无明显差异。结论实验提示心畅可降解聚合物涂层药物洗脱支架置入后有良好的血液相容性,生物性能稳定,支架内表面迅速内皮化,血管有良好的开通率。说明可降解聚合物涂层药物洗脱支架是安全、有效的。     

Two-year outcome of Turkish patients treated with Zotarolimus versus Paclitaxel eluting stents in an unselected population with coronary artery disease in the real world: a prospective non-randomized registry in southern Turkey

Background: Our purpose was to investigate the clinical outcomes of Zotarolimus- and Paclitaxel-eluting stents in Turkish patients with coronary artery disease (CAD). In general, the outcome of drug-eluting stent (DES) placement has a proven efficacy in randomized trials. However, the difference in efficacy between the Zotarolimus and Paclitaxel-eluting stents in unselected Turkish patients is controversial. Therefore, we investigated the clinical outcomes of these two drug-eluting stents in the real-world.Methods: We created a registry and prospectively analyzed data on a consecutive series of all patients who presented to our institution with symptomatic coronary artery disease between February 2005 and March 2007 and who were treated with the zotarolimus- or the paclitaxel-eluting stent. The follow-up period was approximately two years. The primary end-point was major cardiac events, and the secondary end-point was definite stent thrombosis. Informed consent was obtained from all subjects, and the study protocol was approved by the local ethical committee.Results: In total, 217 patients were treated with either the zotarolimus-eluting stent (n = 116) or the paclitaxel-eluting stent (n = 101). The lesions in the 2 arms of the study were treated similarly by conventional technique. At 24-month follow-up the paclitaxel-eluting stent group showed significantly higher non-Q wave myocardial infarction (2.6% vs 5.9%, p: 0.02), Q wave myocardial infarction (1.7% vs 5.9%, p: 0.049), coronary artery binding graft surgery (2.6% vs 6.9%, p: 0.002), and late stent thrombosis (1.7% vs 3.9%, p: 0.046).Conclusions: Zotarolimus-eluting stents demonstrated better clinical outcomes than Paclitaxel-eluting stents in a daily routine practice of coronary intervention in an unselected Turkish population.     

Thiazolidinediones may be effective in the prevention of stent thrombosis with DES

Although rare, stent thrombosis remains a severe complication after drug-eluting stent (DES) implantation owing to its high morbidity and mortality. Biological mechanisms, including delayed or incomplete stent endothelialization, enhanced platelet activity and upregulated expression of prothrombotic factors significantly contribute to stent thrombosis after DES implantation. The thiazolidinediones, a peroxisome proliferators-activated receptor-gamma (PPAR-gamma) agonist, is used in the treatment of patients with type 2 diabetes as an insulin-sensitizing agent. Recent data suggest that TZDs could reduce thrombotic tendency following artery injury through accelerating reendothelialization, inhibiting platelet activity and reducing the expression of prothrombotic factors. We hypothesize that TZDs may exert beneficial effects on reducing the risk of stent thrombosis with DES.     

The short-term effects on restenosis and thrombosis of echinomycin-eluting stents topcoated with a hydrophobic heparin-containing polymer

Although drug-eluting stents (DESs) have become the most effective means of treating coronary artery disease, safety concerns regarding their thrombogenicities remain to be surmounted. Here, we report on a novel type of DES capable of preventing restenosis and thrombosis. The DES was prepared by coating a bare metal stent with echinomycin (an anti-proliferative drug) in polyurethane by a spray drying method. Hydrophobic heparinized polymer was then topcoated onto stent over echinomycin/PU layer by dipping to improve hemocompatibility. The two-layered stent was characterized regarding surface and cross-sectional morphology, drug release pattern, platelet adhesion in vitro, and restenosis in vivo. It was found that the heparin topcoat acts as a diffusion barrier that allows the controlled release of drug in a sustained manner. Also, the heparin coated layer effectively reduced platelet adhesion, indicating excellent hemocompatibility. From the animal test using pigs, it was evident that the developed DESs can minimize neointimal proliferation and thrombus formation. The devised hydrophobic heparinized polymer-coated DES effectively reduced both restenosis and thrombosis, suggesting that they have potential as tools for the treatment of coronary artery diseases.     

In-vitro assays of polymer-coated stents eluting platelet glycoprotein IIb/IIIa receptor monoclonal antibody

The monoclonal antibody (mAb) to the platelet glycoprotein (GP) IIb/IIIa receptor has potent antiplatelet and antithrombotic characteristics shown to reduce thrombus-related major complications after coronary angioplasty. This mAb can be incorporated in drug-eluting stents capable of releasing single or multiple bioactive agents into the bloodstream and surrounding tissues. Stents eluting the monoclonal mouse anti-human platelet glycoprotein IIb/IIIa antibody SZ-262 were tested for their effectiveness in improving the blood compatibility and the antithrombotic characteristics by immunofluorescence and scanning electron microscopy (SEM). The SEM results convincingly demonstrated that the surface of the mAb eluting-stents was completely free of platelet uptake without any sign of cellular debris or proteinaceous deposits, compared with controls. The deformation index of platelets on the L-polylactic acid (L-PLA) coated stents were higher than bare Nitinol intravascular stents, as shown by SEM images. Monoclonal antibody to the platelet GP IIb/IIIa receptor, when eluting from L-PLA polymer-coated stents, effectively inhibits platelet aggregation in the stent microenvironment, thus demonstrating a potential capacity of reducing thrombosis, improving blood flow and arterial patency rates, and inhibiting cyclic blood flow variations. These results highlight the possibility of such monoclonal antibody-eluting stents to reduce or possibly eliminate thrombosis and in-stent restenosis.     

Efficacy of Sirolimus-Eluting Stents Compared with Paclitaxel-Eluting Stents in an Unselected Population with Coronary Artery Disease: 24-Month Outcomes of Patients in a Prospective Non-randomized Registry in Southern Turkey

Background: The efficacy of drug-eluting stents has been shown in randomized trials, but some controversy exists regarding which stent sirolimus-eluting or paclitaxel-eluting is more effective in unselected Turkish patients. Therefore, we investigated the clinical outcomes of patients who were treated with one type of these drug-eluting stents in the real world.Methods: We created a registry and prospectively analyzed data on a consecutive series of all patients who presented to our institution with symptomatic coronary artery disease between February 2005 and March 2007 and who were treated with the sirolimus- or the paclitaxel-eluting stent. The follow-up period after stent implantation was approximately 24 months. The primary end point was a major cardiac event, and the secondary end point was stent thrombosis. Informed consent was obtained from all subjects, and the study protocol was approved by the local ethical committee.Results: In total, 204 patients were treated with either the sirolimus-eluting stent (n = 103) or the paclitaxel-eluting stent (n = 101). The lesions in the 2 arms of the study were treated similarly by conventional technique. At 24-month follow-up, patients who received the paclitaxel-eluting stent showed significantly higher rates of non-Q-wave myocardial infarction (1.9% vs 5.9%; P: .002), target vessel revascularization (1.9% vs 4.9%; P: .002), coronary artery bypass graft surgery (1.9% vs 6.9%; P: .001), and late stent thrombosis (1.9% vs 3.9%, P: .002).Conclusions: Patients who received the sirolimus-eluting stent showed better clinical outcomes compared with those who had the paclitaxel-eluting-stent.