肿瘤微环境调节型细胞器靶向递药系统的研究进展

近年来,利用机体免疫系统进行抗肿瘤的免疫疗法受到了广泛关注。然而抑制性肿瘤微环境限制了免疫治疗的效果,因此克服肿瘤微环境及其中的免疫抑制性细胞的作用成为肿瘤免疫疗法的一大热点。纳米制剂具有重新编程免疫抑制性微环境的巨大潜力,为免疫治疗提供了有效策略。随着主动靶向性纳米载体技术的不断发展和对药物作用位点研究的不断深入,具有更精准主动靶向功能的亚细胞器靶向性纳米载体材料也受到越来越多的关注。本文简要介绍了各亚细胞器与肿瘤的关系,概述了基于酸碱性调节、活性氧含量、免疫原性及免疫抑制细胞的肿瘤微环境特点的纳米药物靶向递送系统的设计策略与研究进展,为亚细胞器途径靶向递药系统的构建及其在肿瘤免疫治疗方面的应用提供借鉴和参考。     

细胞膜仿生纳米技术在肿瘤靶向递药系统中的研究进展

纳米技术的发展为构建安全高效、精准可控的药物递送系统(drug delivery system, DDS)提供了可能。其中,有机或无机合成纳米载体已被广泛报道并用于肿瘤治疗药物的递送,但部分载体存在易被机体内免疫系统清除、制备过程繁琐和体内安全性较差等问题。近年来,随着生物医学的发展,基于仿生技术的生物膜介导的纳米药物递送系统,因其有机整合了天然生物膜的低免疫原性、肿瘤靶向性和智能纳米载体设计的可调控性、多功能性,有望实现纳米技术在肿瘤靶向治疗上的新突破。本文基于细胞膜仿生技术和纳米医学在肿瘤治疗领域的最新进展,从细胞膜仿生纳米技术的实验基础、膜仿生纳米递药平台的分类和在肿瘤靶向治疗上的应用三方面进行阐述,旨在为仿生智能DDS的设计及其在肿瘤靶向治疗中的发展提供参考。     

细胞膜仿生递药系统在肿瘤治疗中的研究进展

纳米药物递送系统在肿瘤精准医疗领域具有良好的应用前景,但有机或无机合成的纳米材料存在制备过程繁琐和易被机体内免疫系统识别、清除等问题。受自然界生物系统的启发,生物细胞膜介导的仿生纳米递药系统近年来成为研究热点。生物膜仿生递药系统通过机体内源性细胞膜对纳米载体表面进行包覆修饰,有效地将天然生物膜“自体”性质和“人工”功能载体的优势相融合,赋予其肿瘤靶向性,低免疫原性和血液长循环等特点。基于纳米药物和细胞膜仿生技术在肿瘤精准医疗领域的研究进展,对细胞膜仿生修饰纳米粒的实验基础、膜仿生纳米递药系统的构建及在肿瘤靶向化疗、免疫治疗、光热治疗上的应用三方面进行综述,并对未来研究进行展望。     

生物膜纳米载药系统在肿瘤免疫治疗中的应用进展

目的:综述生物膜纳米载药系统在肿瘤免疫治疗中的应用,为肿瘤免疫治疗的纳米药物设计及临床转化提供思路。方法:以"肿瘤免疫治疗""生物膜纳米系统""药物靶向递送""抗原递呈""纳米载体""肿瘤疫苗""Tumor immunotherapy""Bionic membrane nanosystems""Drug targeted delivery""Antigen presentation""Nano carrier""Tumor vaccine"等为中英文关键词,在中国知网、万方数据、PubMed、Elservier、SpringerLink等数据库中组合查询2000年1月-2019年10月发表的相关文献,总结生物膜纳米载药系统在肿瘤免疫治疗中的应用。结果与结论:共检索到相关文献379篇,其中有效文献52篇。生物膜纳米系统在免疫刺激性细胞因子(利用细胞膜磷脂双分子层内疏水外亲水的特性,形成天然的载药空腔负载化疗药,同时利用细胞膜表面的功能性蛋白对免疫刺激因子的吸附作用,以达到化疗和免疫治疗的协同作用)、单克隆抗体[如用红细胞膜包被抗人端粒酶逆转录酶(hTERT)的单克隆抗体(mAb),以增加抗体类生物药物在体内的长效循环和细胞摄取]、免疫检查点抑制剂(将PD-L1表达在293T细胞膜上,有助于打破树突状细胞的免疫沉默)、肿瘤疫苗(利用肿瘤细胞自身细胞膜包裹免疫佐剂,获得伪装后的仿生纳米疫苗,以刺激T细胞的增殖和免疫应答)等肿瘤免疫治疗策略方面均具有重要的应用。生物膜纳米载体能够有效保护免疫相关细胞因子、单克隆抗体和免疫检查点抑制剂的生物活性,并通过肿瘤细胞细胞膜和免疫细胞细胞膜等生物膜表面特殊的理化性质实现药物的靶向递送和肿瘤微环境的刺激,提高肿瘤免疫治疗效果。     

细胞膜仿生纳米载体的制备及应用研究进展

由有机或无机纳米材料制备的药物载体系统广泛用于药物靶向递送和疾病的诊断治疗研究。但其存在靶向性差、体内循环时间短、生物相容性欠佳亟需提高等问题。仿生纳米药物系统是以不同种类的细胞膜修饰纳米载体,利用内源性的细胞膜提高载体的体内生物相容性、实现更精准的靶向、甚至由细胞自身的免疫原性产生免疫治疗作用。对细胞膜仿生纳米载体技术的原理、方法及其靶向机制和治疗作用作一综述,为新型给药系统研究提供思路。     

克服肿瘤多药耐药的药物共递送纳米载体的设计及研究新方向

多药耐药（multidrug resistance，MDR）是肿瘤治疗成功的主要障碍，药物共递送纳米载体因其肿瘤靶向、控制释放、一致的药动学曲线而被认为是克服MDR的有效策略。本综述总结了当前克服MDR的药物共递送纳米载体的设计思路，并分析了具有前景的研究方向，包括精确药物负载纳米载体、呈时序释放的纳米载体和对肿瘤微环境设计纳米载体，这些新兴策略为临床肿瘤治疗提供了新颖且更好的定制组合方案。     

叶酸受体介导的肿瘤靶向纳米递药系统

叶酸受体在上皮源性的恶性肿瘤细胞膜表面高度表达。叶酸靶向纳米递药系统具有叶酸-叶酸受体主动靶向和纳米递药系统被动靶向的双重优势,可实现化疗药物对肿瘤组织的靶向递送,有效提高药物疗效,减少毒副作用。本文就近年来研究较多的叶酸-脂质体、叶酸-树枝状聚合物、叶酸-聚合物胶束、叶酸-纳米球等叶酸受体介导的肿瘤靶向递药系统进行综述。     

基于线粒体靶向纳米药物递送系统的设计及研究进展

线粒体参与能量提供、信号传导、细胞分化等诸多生理活动,在肿瘤的发生发展中起重要作用,以线粒体为靶标是一种癌症治疗新策略。利用纳米技术构建线粒体靶向纳米药物递送系统可改善传统药物溶解性,延长药物半衰期,提高其生物利用度及降低不良反应,有望解决肿瘤治疗中出现的耐药性问题。本综述着重于癌症治疗领域,介绍了线粒体靶向纳米药物递送系统用于癌症治疗的机制,并概述了近5年线粒体靶向纳米药物递送系统的设计思路、分类及应用研究,最后拓展分析了以线粒体为靶点的其他研究如仿生载体等,并讨论其存在的优势及不足,为未来纳米药物靶向线粒体的深入研究提供了依据。     

肿瘤微环境响应性与调节性递药系统研究进展

肿瘤微环境的复杂性为肿瘤靶向递药带来挑战的同时也赋予其一定的机遇。一方面,通过利用肿瘤微环境的特征信号为刺激源,构建各种各样的响应性递药系统,可实现药物在肿瘤部位的靶向递送;另一方面,肿瘤部位异质的新生血管和异生的胶原等所引起的较高的固体瘤压力及肿瘤间质压等成为药物递送的巨大障碍,极大地降低了递药系统的递送效率。许多研究致力于通过调节肿瘤微环境,使其更利于药物在肿瘤部位的递送。本文综述了基于肿瘤微环境响应性纳米递药系统的设计及调节肿瘤微环境以提高肿瘤靶向递送效率的最新进展,并对其中存在的问题及未来的发展进行讨论。     

肿瘤微环境响应型的RNA药物递送系统的研究进展

肿瘤作为全球危害人类健康的重大疾病之一,亟需寻找更加安全高效的治疗方案。核糖核酸(ribonucleic acid, RNA)药物的基因疗法可以调节肿瘤相关基因的表达,已在临床前和临床试验中展示出良好的抗肿瘤治疗潜力。基于肿瘤组织在pH、特异性酶浓度或氧化还原梯度变化等微环境信号特征与正常组织存在差异性,各类微环境响应型纳米载体正在被研究开发用于递送RNA药物,实现对肿瘤组织与细胞的靶向递送,提高RNA药物的抗肿瘤疗效并且降低不良反应。本文综述了肿瘤微环境的病生理特征以及各类肿瘤微环境响应型载体策略,旨在为设计安全高效的RNA药物肿瘤靶向递送系统提供参考。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.