生物携氧治疗剂的研究：作用与应用

文题释义：生物携氧治疗剂：是指具有载氧气功能、维持血液渗透压和酸碱平衡及扩充血容量的人工制剂。目前主要有氟碳化合物和血红蛋白类氧载体两大类。与简单的扩容剂相比,生物携氧治疗剂除能维持血液渗透压、酸碱平衡和血容量外,还具有较好的携氧能力,能向局部缺氧组织输氧。是临床上一种具有广阔的应用前景的携氧制剂。 血红蛋白类氧载体(Hemoglobin-based oxgen carriers,HBOCs)：是一类通过血红蛋白分子表面化学修饰或分子间交联而形成分子量较大的血红蛋白制品,原料血红蛋白主要来源于人或动物血,目前应用较为广泛的是戊二醛聚合猪血红蛋白(pPolyCHb)和戊二醛聚合牛血红蛋(HBOC-201)。 背景：健康人献血虽然一定程度地缓解了临床用血的燃眉之急,但是单纯依靠健康人献血已不能从根本上解决血源短缺和血液安全性的问题。 目的：结合生物携氧治疗剂开发的意义,对生物携氧治疗剂所独有的特点进行阐述,总结近年来对生物携氧治疗剂的研究现状及应用进展,为进一步研究生物携氧治疗剂的作用及临床应用提供一定的理论基础。 方法：作者检索CNKI、万方、Pub Med等数据库中自2015年1月至2019年8月的相关文章,英文检索词为“blood substitute, hemoglobin oxygen carrier, artificial blood,oxygen-carrying therapeutic agent”,中文检索词为“血液代用品,血红蛋白类氧载体,人工血液,携氧治疗剂”,检索文献类型为研究原著、综述。初检文章418篇,再经过严格筛选后,对符合要求的46篇文献进行分类综述。 结果与结论：生物携氧治疗剂的临床效果较好,可维持血液渗透压、酸碱平衡和血容量,还具有较好的携氧能力,能向局部缺氧组织输氧并维持较长时间。它还具有易于贮存、便于运输等特点。生物携氧治疗剂在外科手术中得到广泛的应用,对扩充血容量、加快术后恢复有很大帮助,故其研发对于外科创伤及复苏、失血性休克、恶性贫血、心肌梗死等疾病均具有重要意义,并体现出良好的临床应用前景。 ORCID: 0000-0002-0365-4638(黄文华) 中国组织工程研究杂志出版内容重点：人工关节;骨植入物;脊柱;骨折;内固定;数字化骨科;组织工程     

红细胞代用品的研究进展

红细胞代用品是指在临床输血中临时替代人全血的各类氧载体。与传统输血方式相比 ,红细胞代用品具有来源广泛、安全洁净、适于急救等优点。目前正在研究中的红细胞代用品包括全氟碳化合物、化学修饰血红蛋白、基因重组血红蛋白、微囊化血红蛋白等。本文对以上各种主要制品的研究进展作了全面综述     

血红蛋白氧载体的最新研究进展

由于全球性血液储备量不足及血液制品的安全问题,急需开发一种安全有效的血液替代品。长期以来,研究人员一方面采用聚合、交联、偶联等方式对分离纯化的血红蛋白进行化学修饰,获得化学修饰类血红蛋白氧载体;另一方面,研究者发现蚯蚓血红蛋白是一种大分子细胞外呼吸蛋白,其理化性质更加稳定,半衰期更长,且不易引起免疫反应,是血红蛋白氧载体研究的另一个重要方向。因此,文章从化学修饰血红蛋白和蚯蚓血红蛋白两个方面阐述人工氧载体的最新研究进展,对蚯蚓血红蛋白特性及作为治疗性氧载体、细胞培养添加剂的临床应用进行重点介绍,并提出未来研究方向。     

红细胞代用品的研究进展

输血来源有限，且输注后可能引起严重的不良反应，因而国内外科学家对以携氧液作为输血替代品进行了长达一个多世纪的探索。迄今为止，几种第一代红细胞代用品已经有望获准上市。各种产品有其独自的生理特性、生物活性和副作用。作者着重综述了基于人，牛和重组来源血红蛋白衍生的红细胞代用品以及携氧氟碳乳剂，描述了多聚血红蛋白（PolyHeme，HBOC-201，Hemolink），双阿司匹林分子内交联血红蛋白（HemAssist），重组人血红蛋白（rHb1．1，rHb2．0），共轭血红蛋白（PHP，MP4），血红蛋白微囊，全合成型白蛋白-血红素载体和氟碳乳剂（Oxygent，Oxyiluor，Perftoran）等红细胞代用品的研制情况，产品特性，生理学效应，实（试）验效能和副作用。作为氧治疗剂进行研发，可能成为今后红细胞代用品研制的发展方向。     

医用壳聚糖膜的制备与应用

背景：壳聚糖膜在人工肾膜-透析膜、人工皮肤、口腔溃疡膜、牙周引导组织再生膜、药物载体控释膜及相关组织工程等方面已取得了令人欣慰的成果。 目的：总结归纳壳聚糖膜的制备,及目前其在用于局部药物控释的应用。 方法：电子检索CNKI数据库、读秀学术搜索等数据库收录的壳聚糖膜的制备和应用于药物控释载体的相关综述和实验研究报告,分析壳聚糖制备的研究进展和应用于药物控释载体的研究进展。 结果与结论：共纳入壳聚糖制备与局部药物控释相关文献21篇。壳聚糖的制备条件与其应用于药物控释载体之间有着密不可分的关系,但总结规范及其相关性尚不明朗,尚期待大量研究。对壳聚糖的制备条件与其应用于药物控释载体的关系的研究也仍需要进一步努力,探索适宜壳聚糖膜制备条件,制备成功最适的药物控释载体是研究者的工作重点。     

人工氧载体的研究现状及展望

人工氧载体是能运输和释放氧到组织并具有扩容作用的非细胞液。由于它无需交叉配血、无病毒和细菌污染、无免疫排斥作用、保存时间长、粘度低 ,还可以节约有限的血资源 ,近年来其研究发展很快。新型人工氧载体包括全氟化碳和血红蛋白制剂等两大类 ,可以代替血液、胶体和晶体溶液 ,因而可以在运氧中起到重要作用     

人工肺的膜材料：研究与应用

背景：人工肺是一项生命支持技术,可以在自身肺功能出现衰竭不能维持人体器官充分的氧供时使用,或者从长远发展来看,可永久性地植入人体,部分或完全替代人体肺功能。当前,通过改进膜材料、优化设计以及对各种性能的实验评估和临床评价,人工肺的研究着力于提高气体交换能力和生物相容性,为抢救患者的生命提供更可靠的手段。 目的：利用Scopus数据库及CKNI数据库文献检索和深度分析功能,对人工肺膜材料的文献资料进行多层次探讨分析,根据检索文献结果分析人工肺膜材料的发展状况及趋势。 方法：通过计算机检索Scopus数据库及CKNI数据库中2002/2011有关人工肺膜材料的文献,检索词为“人工肺(artificial lung),膜材料(membrane materials),生物相容性(biocompatibility),膜式氧合器(membrane oxygenator),膜式人工肺(membrane-type artificial lung),中空纤维(hollow fiber),高分子材料(polymer materials)”。 结果与结论：目前人工肺膜的结构形式已从最初的卷筒式、平板折叠式发展到今天广为采用的微孔中空纤维膜式。用于制造中空纤维的材料主要为一些成纤性能良好的高分子材料,如聚丙烯、聚醚砜等。膜式人工肺可以提高气体交换能力和生物相容性。随着高新材料的开发、基础研究的深入和临床经验的积累,人工肺必将开创治疗重症呼吸系统疾患的新局面。Scopus数据库2002-01/2011-12收录人工肺膜材料的相关文献共172篇,该领域的文献产出量发展较平稳,总体无显著增加,《人工器官》杂志发表文献量最多。     

叶酸修饰聚合物和脂质体药物载体及其靶向治疗的研究现状*

背景：叶酸介导的靶向药物载体被广泛研究。 目的：总结叶酸修饰靶向聚合物和脂质体药物载体的研究现状。 方法：由作者应用计算机检索2000-01/2010-12 Web of Science和CNKI数据库,选择叶酸修饰靶向聚合物和脂质体药物载体的相关文章,英文检索词为“folic acid, drug carriers, targeted delivery system, polymer, liposome”,中文检索词为“叶酸,药物载体,靶向,聚合物,脂质体”。共纳入相关文献19 篇进行综述。 结果与结论：叶酸受体在多种肿瘤细胞表面过度表达,而在多数正常组织中的表达仅限于一些难于进入血液循环的上皮细胞顶膜。正因为叶酸受体表达的特性,叶酸受体天然配体——叶酸成为将药物靶向到肿瘤细胞的重要分子。叶酸具有与叶酸受体的高亲和力、低免疫原性等优点,这使得叶酸介导肿瘤靶向的研究得到迅速发展。含叶酸靶向的药物载体体系中,主要分为3大类：即人工合成高分子载体体系、脂质体和天然高分子载体体系。      

改性血红蛋白携氧载体研究进展

天然血红蛋白 ( Hb)经改性处理后可改善稳定性和氧亲合性。近半个世纪的研制产生了三代改性血红蛋白制品 :第一代为化学改性 Hb,已趋成熟 ,有多种制品问世 ,现正进行 ～ 期临床试验 ;第二代为包含了红细胞酶类的化学交联 Hb和利用分子遗传工程制备的重组 Hb;第三代为微包囊 Hb,其结构和功能更接近天然红细胞。Hb的来源除人红细胞外还包括牛 Hb,利用重组 DNA技术从大肠杆菌和酵母菌中提取的重组 Hb及转基因 Hb。     

改性血红蛋白携氧载体研究进展

天然血红蛋白（Ｈｂ）经改性处理后可改善稳定性和氧亲合性。近半个世纪的研制产生了三代改性血红蛋白制品，第一代为化学改性Ｈｖ，已趋成熟，有多种制品问世，现正进行Ⅱ～Ⅲ期临床试验，第二代为包含了红细胞酶类的化学交联Ｈｂ和利用分子遗传工程制备的重组Ｈｂ，第三代为微包裹Ｈｂ其结构和功能更接近天然红细胞。Ｈｂ的来源除人红细胞外还包括牛Ｈｂ，利用重组ＤＡ技术从大肠杆菌和酵母菌中提取的重组Ｈｂ及转基因Ｈｂ。     

Evolution of artificial cells using nanobiotechnology of hemoglobin based RBC blood substitute as an example

The original artificial red blood cells have evolved into oxygen carriers in the form of polyhemoglobin and conjugated hemoglobin. Clinical conditions requiring only oxygen carriers are responding well to these types of oxygen carriers without the need for a complete artificial red blood cell. For those conditions requiring more than just oxygen carriers, new generations of polyhemoglobin containing antioxidant enzymes are being developed. Though a complete artificial red blood cell comparable to red blood cell is still a dream, development in lipid membrane artificial red blood cells and biodegradable polymeric nano artificial red blood cells are steps towards this possibility. The many years of neglect on basic research in the area of blood substitutes have resulted in the lack of important basic knowledge needed for the rapid development of blood substitutes suitable for clinical use. This is further hampered by the mistaken conception that blood substitute is a single entity. We need to look at blood substitutes as consisting of progressively more complicated entities, e.g. oxygen carriers, oxygen carriers with antioxidant activity, and complete red blood cell substitutes. Each of these entities is not applicable to all clinical conditions, but is suitable for specific applications.     

Toward 21st century blood component replacement therapeutics: artificial oxygen carriers, platelet substitutes, recombinant clotting factors, and others

In this brief overview, recent progress and current status of blood substitute research and development is summarized. Current blood substitute development efforts are focused on red blood cell substitutes but substitutes for platelets and other blood components are also in progress. Red cell substitutes currently in various stages of development are semi-synthetic or synthetic oxygen carriers that include "stealth" or "masked" red cells, hemoglobin-based oxygen carriers and perfluorocarbon-based oxygen carriers. Artificial platelets (or platelet substitutes) are in early stages of development and include human platelet fragments or particles of synthetic/semi-synthetic materials or recombinant human serum albumin coupled with platelet surface receptor fragments. Of note, some recombinant clotting factors (Factors VII, VIII, IX) have already been successfully developed and licensed for treatment of hemophilia. In addition, some future approaches and prospects of blood component replacement therapeutics are discussed.     

血液组织工程制品的研究现状

广义上血液代用品包括血浆代用品和血细胞代用品,狭义上主要指红细胞代用品、血小板代用品和白细胞代用品.红细胞代用品主要包括全氟碳化合物类、血红蛋白类(Hb)和微囊化血红蛋白类.目前全世界范围内广泛研究的血红蛋白类红细胞代用品有:以人Hb为基础、以动物Hb为基础及以基因重组人Hb为基础的红细胞代用品.白细胞的功能和免疫问题十分复杂,临床单独输用甚少.目前研究开发的血小板代用品主要是脂质体类和胶原纤维类.     

血红蛋白溶液的研究进展

血红蛋白溶液是近年来研究较多且较有前途的载氧血液代用品,目前主要有修饰血红蛋白和微囊化血红蛋白等,前者是通过化学方法将血红蛋白进行分子间和/或分子内交联,后者则是用人工膜将血红蛋白分子进行包裹。最终目的是降低血红蛋白的氧亲和力,提高向组织释氧能力,同时延长血红蛋白在循环中的半衰期。血红蛋白的来源主要有过期库血及动物(主要是牛)血,随着分子生物学的发展,目前对基因工程血红蛋白的研究正逐步深入。虽然现在已有数种产品进入临床前或I期临床试验阶段,但仍有一定的副作用,尚需进一步研究。     

Role of redox potential of hemoglobin-based oxygen carriers on methemoglobin reduction by plasma components

A functional requirement for all hemoglobin-based oxygen carriers (HBOCs) is the maintenance of the heme-iron in the reduced state. This is necessary for the reversible binding/release of molecular oxygen and minimization of methemoglobin (Fe+3) formation. Acellular hemoglobins are especially susceptible to oxidation and denaturation. In the absence of the intrinsic reducing systems of the red blood cell, the reduced heme-Fe+2 can be oxidized to form increasing levels of methemoglobin that can give rise to free radicals and oxidative cellular damage. If acellular HBOCs are to be utilized as red cell substitutes for oxygen delivery, these carriers must be stabilized in the plasma, the carrier medium. Normal plasma contains reducing components, such as ascorbic acid and glutathione, that can afford protection to these acellular HBOCs through electron-transfer mediated processes. For these components to provide effective reduction to an HBOC, a favorable reduction potential difference must exist between the reducing agent and the HBOC. Using a modified thin-layer spectroelectrochemical method, a determination of the formal reduction potential (vs. Ag/AgCl) of several oxygen carriers, including monomeric myoglobin, tetrameric HbA and HbS, chemically cross-linked HbXL99alpha, polymerized oxyglobin (FDA approved for canine anemia), and the natural cross-linked polymeric Lumbricus hemoglobin, have been determined. In contrast to the negative formal reduction potentials (-155 to -50 mV) obtained for Mb, HbA, HbS, HbXL99alpha, and oxyglobin, Lumbricus hemoglobin exhibited a positive formal reduction potential (approximately 100 mV). These results may help explain the greater effectiveness of the tested reducing agents to reduce met Lumbricus hemoglobin, compared to the other HBOCs, back to the required reduced form necessary for physiological binding/release of oxygen. Each reducing agent was capable of reducing met Lumbricus hemoglobin to the fully reduced state, although the kinetics of these reactions were different. HbA, HbXL99alpha, and oxyglobin were only partially reduced (10 to 37%) by glutathione, beta-NADH, and ascorbic acid under similar conditions.     

阳离子交换色谱柱上聚合血红蛋白研究

采用柱上聚合的方法制备血红蛋白溶液，解决传统血红蛋白聚合过程中由于戊二醛的活性过高导致平均分子量大、产物分子量分布宽的问题。该方法利用阳离子交换剂对修饰度（聚合度）小的血红蛋白吸附能力大的原理，使其在柱上富积，同时加入戊二醛进行聚合反应。结果表明该方法能比较有效地缩小聚合血红蛋白的分子量分布。     

Blood substitutes and redox responses in the microcirculation

Transfusion of hemoglobin-based blood substitutes, designed for their plasma expansion and oxygen transport capabilities, has resulted in some major problems, such as organ dysfunction, during clinical trials. Experimental evidence demonstrates that these hemoglobins damage tissue by producing highly reactive oxygen species. Although cell-free hemoglobin may present a low risk to people with normal redox status, patients who are sick and have a poor antioxidant status may be at risk. Oxidative damage is particularly dangerous in the microcirculation because excess leakage of plasma components into the interstitium will disturb the fluid balance between blood and tissue and alter the kinetics of delivery of intravascularly injected drugs, and endogenous enzymes and hormones, to various tissues. In this review, the redox chemistry of hemoglobin-based blood substitutes is briefly described, and their effects on cultured endothelial cells, and on the exchange properties of the microvasculature, are discussed. Taking into account the possible mechanisms by which oxidative damage can occur, various methods to reduce the deleterious effects of blood substitutes in vivo are evaluated. Finally, several possible cell signaling pathways that are triggered in endothelial cells, in response to modified hemoglobins, are considered in terms of protecting microvascular function.     

What happened to blood substitutes?

Concerns about the safety and adequacy of the blood supply have fostered twenty years of research into the so-called "blood substitutes" among them the oxygen carriers based on modified hemoglobin. Although none of these materials has yet been licensed for use in North America or Europe, the results of research and clinical trials have increased our understanding of oxygen delivery and its regulation. In particular, the examination of the basis for the vasoactivity observed with some of the hemoglobin based oxygen carriers has led to the insight that several colligative properties of hemoglobin solutions, such as their diffusion coefficient for oxygen, viscosity and colloid oncotic pressure, are important determinants of efficacy.     

Automated quantitation of hemoglobin-based blood substitutes in whole blood samples.

It is necessary to develop methods for accurate monitoring of cell-free hemoglobin in circulation. Routine monitoring of circulating cell-free hemoglobin will be useful for evaluating the efficacy of blood substitute administration andfor determining the clearance rates of the blood substitute from circulation. In addition, discriminating between cell-free hemoglobin and cell-associated hemoglobin will enable accurate determination of RBC indices, mean cell hemoglobin and mean corpuscular hemoglobin concentration, in individuals receiving hemoglobin-based blood substitutes. As colorimetric methods used by hematology analyzers to quantitate the hemoglobin value of a blood sample cannot distinguish between cell-associated and cell-free hemoglobin, it is currently not feasible to quantitate the levels of hemoglobin substitutes in circulation. The advent of a technology that measures volume and hemoglobin concentration of individual RBCs provides an alternative strategy for quantitating the cell-associated hemoglobin in a blood sample. We document that the combined use of cell-based and colorimetric hemoglobin measurements provides accurate discrimination between cell-associated and cell-free hemoglobin over a wide range of hemoglobin levels. This strategy should enable rapid and accurate monitoring of the levels of cell-free hemoglobin substitutes in the circulation of recipients of these blood substitutes.