去唾液酸糖蛋白受体介导的肝靶向研究进展

目的 介绍去唾液酸糖蛋白受体(asialoglycoprotein receptor,ASGPR)介导的药物和基因肝靶向作用和机制,及其在治疗肝癌和乙型肝炎实验研究方面的最新进展。方法 查阅和选取针对性强、相关度高的文献,总结和归纳ASGPR介导的药物和基因肝靶向用于治疗肝癌和乙型肝炎的最新研究进展。结果 ASGPR是肝细胞的一种重要且高效的内吞受体,可用于介导药物和基因的肝靶向递送。结论 ASGPR介导的药物和基因肝靶向有望成为肝癌和乙型肝炎治疗的有效手段。     

无唾液酸糖蛋白受体介导的肝靶向药物

将肝细胞膜上无唾液酸糖蛋白受体所能识别的配基体为载体与药物相结合获得肝靶向药物，本文着重介绍无唾液酸糖蛋白受体介导的肝靶向药物的作用机制，药物载体及应用。     

基于去唾液酸糖蛋白受体的肝靶向药物的研究

去唾液酸糖蛋白受体(asialoglycoprotein receptor, ASGPR)是一种在肝实质细胞表面高度表达的受体,它可以特异性识别和结合末端带有半乳糖或N-乙酰基半乳糖胺残基的分子,通过网格蛋白介导其内吞并转运至溶酶体中降解。基于这一特性, ASGPR介导的肝靶向药物递送会增加药物在肝脏中的分布、减少药物潜在不良反应并降低给药剂量。本文全面综述了ASGPR的表达、组成与结构、结合及内吞,系统总结了基于ASGPR的配体设计、优化及其释放策略,并展望该受体在药物开发中的应用。     

肝靶向药物的研究进展

综述肝靶向药物的研究进展.治疗性的肝靶向药物有毫微粒及微球制剂、免疫导向药物、糖蛋白受体导向药物、信号靶向药物、肝靶向降胆固醇药物、抗疟药及促骨骼生长药等;诊断性的肝靶向药物有磁性毫微粒、无唾液酸糖蛋白受体介导的肝靶向药物等.肝靶向药物的研究开发,为肝脏疾病及其相关疾病的诊断和治疗开辟了广阔的前景.     

肝靶向抗癌药NGA-DHAQ的合成研究

以D－半乳糖和人血清白蛋白（HSA）合成无唾液酸糖蛋白受体的特异性配体一半乳糖基拟糖白蛋白（neoglycoalbumin,NGA）;以NGA为载体通过丁二酰基桥将米托蒽醌（mitoxantrone,DHAQ）与其偶联,得到肝靶向药物NGA－DHAQ,紫外光谱和HPLC分析表明：NGA－DHAQ为化学偶联物,在血液中稳定。     

半乳糖多聚赖氨酸的肝靶向特征

以还原胺化法合成了半乳糖多聚-L-赖氨酸(GalPLL), 并首次利用放射性示踪实验测定了GalPLL在小鼠体内的肝靶向特征. 结果表明, GalPLL具有较高的肝靶向性, 其在体内的分布形式与肝细胞去唾液酸糖蛋白受体(ASGPR)的内源性配体去唾液酸胎球蛋白(ASF)相似. ¹²⁵I标记的GalPLL经静脉注入小鼠体内后, 主要被肝脏吸收, 在注射后5 min时肝脏的最大吸收为注射总量的38.9%, 比人血清白蛋白高5.7倍. 肝脏对GalPLL的吸收可特异地被ASF及非标记的GalPLL抑制, 但不能被未半乳糖基化的多聚-L-赖氨酸抑制, 证明GalPLL是通过肝细胞ASGPR介导的内吞作用特异地被肝脏吸收的. 由于GalPLL不但具有较高的肝靶向性,而且与ASGPR的天然配体相比在合成和应用方面均具有许多优势, 因此有望成为进行药物或基因肝靶向运送的良好载体.     

乌司他汀对体外循环下冠脉旁路移植术患者围手术期肺脏的保护作用

目的介绍去唾液酸糖蛋白受体（asialoglycoprotein receptor,ASGPR）介导的药物和基因肝靶向作用和机制,及其在治疗肝癌和乙型肝炎实验研究方面的最新进展。方法查阅和选取针对性强、相关度高的文献,总结和归纳ASGPR介导的药物和基因肝靶向用于治疗肝癌和乙型肝炎的最新研究进展。结果ASGPR是肝细胞的一种重要且高效的内吞受体,可用于介导药物和基因的肝靶向递送。结论ASGPR介导的药物和基因肝靶向有望成为肝癌和乙型肝炎治疗的有效手段。     

肝靶向水溶性药物纳米化的研究进展

目前,水溶性药物的肝靶向性研究一般有网状内皮细胞吞噬的被动靶向和基于肝受体识别的主动靶向。被动靶向主要依赖于微粒的大小及表面性质,主动靶向利用分子和受体的特异性配体的识别,肝实质细胞中的去唾液酸糖蛋白作为肝靶向的有效靶点而受到广泛研究。主动靶向制剂是利用肝受体的识别,使药物具有高度靶向性、缓控释性;被动靶向主要是利用纳米粒的小尺寸效应使其具备奇特的物理、化学特性。药物适合于制成哪种类型,要根据靶向部位要求和药物理化性质具体而定。     

脂质体肝实质细胞靶向性研究

目的 脂质体经配体修饰后介导受体细胞,以达靶向给药。方法 肝实质细胞上无唾液酸糖蛋白受体(ASGP-R)的配体无唾液酸胎球蛋白(AF)修饰脂质体得AF-SSL。将ASGP-R重组于脂质双分子膜(BLM)得ASGP-R-BLM,与AF-SSL相互作用,监测BLM膜电参数变化,确定受体-配体间识别反应;用3H标记方法测AF-SSL与肝实质细胞在体内外靶向性;将AF-SSL包抗癌药阿霉素(ADM),考察其抗癌药效。结果ASGP-R-BLM稳定时间随AF-SSL加入量增加而缩短,表现出明显的量效关系,证明在ASGP-R-BLM与AF-SSL之间有特异识别反应;体外AF-SSL与肝实质细胞结合率明显高于无AF修饰脂质体SSL(在第10和90 min时P<0.05,在第30和60 min时P<0.01);抗肝癌疗效,AF-SSL组大鼠存活期显著长于无AF修饰组,且对心、肾、肺的毒副作用小。结论配体修饰脂质体达到主动靶向对应受体细胞是可行的,本文为脂质体细胞水平靶向给药提供依据。     

血清糖蛋白电泳分析在肝病诊断中价值的探讨

为探索血清糖蛋白电泳在肝病诊断中的价值。对200例各种肝病和40例正常人进行了血清糖蛋白电泳分析。结果:肝硬变、慢活肝、慢迁肝α1糖蛋白、α2糖蛋白明显低于正常(P<0．01)。以肝硬化组降低最为显，γ糖蛋白带明显高于正常(P<0．01)。急性肝炎组与正常对照组无显差异。肝癌组：α1糖蛋白、α2糖蛋白明显高于正常(P<0．01)，γ、β糖蛋白带明显低于正常。说明血清糖蛋白电泳是一项简便，易于普及的肝病诊断和鉴别诊断试验．特别是对肝癌和其它肝病的鉴别诊断方面有着重要价值，明显优于目前临床普遍采用的血清蛋白电泳分析。     

联糖米托蒽醌的趋肝性研究

目的：合成肝靶向药联糖米托蒽醌（ＮＧＡＤＨＡＱ）的趋肝性研究。方法：以合成配体半乳糖基拟糖白蛋白（ｎｅｏｇｌｙｃｏａｌｂｕｍｉｎ,ＮＧＡ）为载体,与抗癌药物米托蒽醌（ｍｉｔｏｘａｎｔｒｏｎｅ,ＤＨＡＱ）偶联得肝靶向抗癌药物ＮＧＡＤＨＡＱ。采用紫外光谱和ＨＰＬＣ确证其偶联的形式及在血液中的稳定性。用９９ｍＴｃ标记后进行家兔放射性显像及小鼠体内的分布实验。结果：ＮＧＡＤＨＡＱ为化学偶联物且在血中很稳定,家兔及小鼠肝中药物的量均在５ｍｉｎ时达最大,分别占全身放射量的６５．１％和６５．４％±４．３％（ｎ＝３）。结论：说明ＮＧＡＤＨＡＱ具肝靶向分布性。     

99mTc-neoglycoalbumin (NGA)-binding to human hepatic binding protein (HBP) in vitro.

1 Neoglycoalbumin (NGA) was synthesised by covalent coupling of 2-imino-2-methoxyethyl-1-thio-beta-D-galactopyranoside (IME-thiogalactose) to the primary amino groups of human serum albumin (HSA). NGA was purified by ultrafiltration and size exclusion h.p.l.c. (SEC). 99mTc-labelling was performed with and without SEC purification. 2 Estimation of 99mTc-NGA-binding to human hepatic binding protein (HBP) revealed a complex behaviour indicating saturable high- and low-affinity sites. The high-affinity binding capacity was 1.1 +/- 0.4 pmol mg-1 human liver plasma membrane protein, the low-affinity binding capacity was 6.2 +/- 1.8 pmol mg-1 liver plasma membrane protein. The apparent equilibrium dissociation constants were 2.4 +/- 1.2 and 18.4 +/- 4.8 nM, respectively. 3 Specific binding of 99mTc-NGA to human HBP in the presence of 100 microM unlabelled NGA, Ca++ and Mg++ at pH 7.5 and 37 degrees C reached 85 +/- 5% at equilibrium. The amount of ligand specifically bound increased with the amount of human liver membrane protein added. The concentration of unlabelled agonist necessary to displace 50% of ligand bound amounted to 100 nM.     

99mTc-HL91显像监测荷瘤鼠高压氧后乏氧状况

目的 99mTc-HL91乏氧显像评价肿瘤高压氧后的乏氧状况.方法 20只荷H22肝癌KM小鼠随机分为4组,每组5只;(1)对照组,只进行99mTc-HL91乏氧显像;(2)15 min组,出高压氧舱后15 min行99mTc-HL91乏氧显像;(3)30 min组,出高压氧舱后30 min行99mTc-HL91乏氧显像;(4)60 min组,出高压氧舱后60 min行99mc-HL91乏氧显像.在平面图像上,通过核医学感兴趣区(regionfinteresting,ROI)技术,计算肿瘤与对侧相应部位放射性比值(T/NT),图像采集结束后立即处死小鼠,完整剥离肿瘤,称重并计算放射性计数,计算肿瘤微分摄取率(DUR).结果 15 min组、30 min组DUR及T/NT与对照组比较,差异有统计学意义(P＜0.05),60 min组与对照组比较,差异无统计学意义(P＞0.05).结论 99mTc-HL91显像是一种有价值的评价肿瘤高压氧后乏氧状况的方法.     

~(99m)Tc-ASODN-EGF的小鼠体内分布和兔药动学

目的:研究c-erbB2反义寡脱氧核苷酸(ASODN)探针99mTc-ASODN-EGF的体内分布和药动学特性。方法:小鼠尾静脉注射99mTc-ASODN-EGF 370 kBq(10μC i).150μL-1,于0.5,1,2,4,8,24 h取血、肝、脾、肾等组织器官,测定每分钟放射性计数(cpm),并准确称重,计算每克组织百分注射剂量率(%ID.g-1)。兔经左侧耳缘静脉注射99mTc-ASODN-EGF 1110 kBq(30μC i).2 mL-1,于1,3,5,10,15,20,25,30,40,60,120,240,360 m in从右侧耳缘静脉采血约0.2 mL,测定cpm,准确称重,计算每克血液每分钟放射性计数,用3P97软件计算药动学参数。结果:99mTc-ASODN-EGF在小鼠肝、肾、脾和肺的放射性分布较高,1 h的%ID.g-1分别为22±8,7.4±2.0,46±28和13±7。在心、脑、骨和肌肉的放射性分布很低。兔药动学参数符合二室模型,t12α为(0.32±0.07)h,t12β为(9±3)h,Vc为(1.2±0.8)cpm.kg-1,Cl为(0.061±0.023)cpm.h-1。结论:99mTc-ASODN-EGF的组织器官分布和药动学特性能满足临床显像的要求,可用于肿瘤靶基因的显像。     

Biodistribution of 99mTc‐sunitinib as a potential radiotracer for tumor hypoxia imaging

Tyrosine kinases are groups of enzymes, which are over‐expressed in solid tumor cells, representing good targets for different drugs such as sunitinib (N‐[2‐(diethylamino)ethyl]‐5‐{[(3Z)‐5‐fluoro‐2‐oxo‐2,3‐dihydro‐1H‐indol‐3‐ylidene]methyl}‐2,4‐dimethyl‐1H‐pyrrole‐3‐carboxamide). The aim of this work was to design and synthesize ^99mTc‐sunitinib radiotracer and to study its tumor binding specificity as a novel selective radiopharmaceutical for tumor hypoxia imaging. The in vivo biodistribution of ^99mTc‐sunitinib in tumor bearing mice showed high target/non‐target (T/NT) ratio (T/NT ~ 3 at 60 min post injection). This preclinical high biological accumulation in tumor cells suggests that ^99mTc‐sunitinib is ready to go through the clinical trials as a potential selective radiotracer able to image tumor hypoxia.     

Mechanical and current responses to neurotensin in the smooth muscle of guinea-pig intestine

1 The effects of neurotensin (NT) on the mechanical activity of the smooth muscle and membrane currents of enzymatically-dispersed single smooth muscle cells of guinea-pig intestine were investigated by the isometric tension recording method and the whole-cell patch clamp technique, respectively. 2 NT (0.3–670 nm ) produced an initial relaxation followed by a contraction in segment preparations of the jejunum and ileum. Atropine (0.2 μm ) abolished the contraction. In 30% of ileal segments, NT produced a slowly-developed contraction in the presence of atropine. The atropine-resistant contraction was insensitive to tetrodotoxin (TTX, 0.2 μm ). The relaxant effect of NT was unaffected by TTX (0.2 μm ) and guanethidine (2 μm ), but markedly reduced or abolished by apamin (67 nm ). 3 In segment preparations of the colon and rectum, NT produced a biphasic response, similar to that in the small intestine, or a triphasic one (relaxation, contraction and relaxation). The contractile effect of NT was affected neither by atropine (0.2 μm ) nor by TTX (0.2 μm ). The first relaxation in response to NT was similar in pharmacological properties to that in the small intestine. 4 Responses to NT in longitudinal muscle strips were similar to those in segment preparations. The taenia caecum responded to NT with a contraction alone and the effect was unaffected by atropine (0.2 μm ) and TTX (0.2 μm ). 5 NT had little or no effect on the mechanical activity in the circular muscle of the small intestine. In the circular muscle of the large intestine, NT had a weak inhibitory effect on the spontaneous activity which was followed by a small rise in muscle tone. Apamin (67 nm ) converted the biphasic response to a contraction. 6 In cells dialysed with a KCl-based solution under voltage clamp at 0 mV, NT (5 μm ) produced a brief, outward current in a very small fraction of cells (4 out of 40 cells). When cells were dialysed with a CsCl-based solution under voltage clamp at – 50 or – 60 mV, no current response to NT (5 μm ) was observed in all 37 cells, but NT increased inward Ca²⁺ currents evoked upon depolarization. 7 From these results, it appears that there is a regional difference in the mode of action of NT to contract and relax the smooth muscle of guinea-pig intestine, and NT acts on its receptors on the smooth muscle to enhance activation of voltage-dependent Ca²⁺ channels, which underlies the slow contraction in the longitudinal muscle of the intestine.     

磁性明胶微球体内分布实验研究

对磁性明胶微球进行了同位素标记。用γ-闪烁照相技术观察了磁性明胶微球在兔体内的分布。结果表明:靶部位的放射活性加磁场是未加磁场的15倍,而且施加磁场时间长和磁场强度大有利于磁性明胶微球定位于靶区。文中也介绍了自行设计的外加磁场装置。     

(99m)technetium-HYNIC(tricine/TPPTS)-Aca-bombesin(7-14) as a targeted imaging agent with microSPECT in a PC-3 prostate cancer xenograft model

The peptide bombesin (BN) and derivates thereof show high binding affinity for the gastrin-releasing peptide receptor (GRPR), which is highly expressed in primary and metastasized prostate cancer. We have synthesized a new BN-based radiopharmaceutical (99m)technetium-HYNIC(tricine/TPPTS)-Aca-BN(7-14) ((99m)Tc-HABN) and evaluated its GRPR targeting properties in vitro and in a xenograft tumor model for human prostate cancer in athymic mice. (99m)Tc-HABN was synthesized, and its lipophilicity and stability were investigated. The IC(50), internalization and efflux properties were determined in vitro using the GRPR expressing human prostate cancer cell line PC-3. (99m)Tc-HABN biodistribution and microSPECT imaging were performed in PC-3 tumor-bearing athymic mice. (99m)Tc-HABN was prepared with high labeling yield (>90%), high radiochemical purity (>95%) and a specific activity of ~19.8 MBq/nmol. The partition coefficient log D value was -1.60 ± 0.06. (99m)Tc-HABN proved to be stable in human serum for 6 h. The IC50 of HYNIC-Aca-BN(7-14) was 12.81 ± 0.14 nM. Incubation of PC-3 cells with (99m)Tc-HABN demonstrated rapid cellular internalization and a long intracellular retention time. When mice were injected with (99m)Tc-HABN, the activity was predominantly cleared via the kidneys. Uptake in the tumor was 2.24 ± 0.64% ID/g after 30 min, with a steady decrease during the 4 h study period. In vivo experiments with a blocking agent showed GRPR mediated uptake. (99m)Tc-HABN microSPECT imaging resulted in clear delineation of the tumor. (99m)Tc-HABN is a novel BN-based radiopharmaceutical that proved to be suitable for targeted imaging of prostate cancer with microSPECT using the human prostate cancer cell line PC-3 in a xenograft mouse model.     

A 99mTc‐tricine‐HYNIC‐labeled peptide targeting the neurotensin receptor for single‐photon imaging in malignant tumors

In this study, a new neurotensin (NT) analog was labeled with ^99mTc via HYNIC chelator and tricine as coligand and investigated further. An NT (7–13) analog was prepared, and labeling with ^99mTc was performed. The internalization rate and biodistribution of radiopeptide were studied in HT‐29 cells and nude mice bearing tumor, respectively. Radiolabeling with ^99mTc was performed at high specific activities (54 MBq/nmol) with an acceptable labeling yield (>95%). In vitro cell line studies showed a specific internalization uptake up to 13.23 ± 0.45% during 4 h which was blocked in the presence of excess cold peptide to 0.83 ± 0.15%. In biodistribution studies, uptake was observed in NT receptor‐positive organs so that after 1 h the uptakes in mouse intestine and tumor were 1.23 ± 0.16% ID/g and 1.12 ± 0.11% ID/g, respectively. In animals co‐injected with excess cold peptide, reduction uptake in tumor and intestines were 73% (1.10% vs. 0.29% ID/g at 4 h) and 61% (1.22% vs. 0.47% ID/g at 4 h) respectively. Predominant renal excretion pathway with a highest accumulation of activity in bladder was observed for this radiopeptide. This radiolabeled peptide could be a candidate for detection of NT positive tumors.