Physicochemical predictors of Multi‐Walled Carbon Nanotube–induced pulmonary histopathology and toxicity one year after pulmonary deposition of 11 different Multi‐Walled Carbon Nanotubes in mice

Multi‐walled carbon nanotubes (MWCNT) are widely used nanomaterials that cause pulmonary toxicity upon inhalation. The physicochemical properties of MWCNT vary greatly, which makes general safety evaluation challenging to conduct. Identification of the toxicity‐inducing physicochemical properties of MWCNT is therefore of great importance. We have evaluated histological changes in lung tissue 1 year after a single intratracheal instillation of 11 well‐characterized MWCNT in female C57BL/6N BomTac mice. Genotoxicity in liver and spleen was evaluated by the comet assay. The dose of 54 μg MWCNT corresponds to three times the estimated dose accumulated during a work life at a NIOSH recommended exposure limit (0.001 mg/m³). Short and thin MWCNT were observed as agglomerates in lung tissue 1 year after exposure, whereas thicker and longer MWCNT were detected as single fibres, suggesting biopersistence of both types of MWCNT. The thin and entangled MWCNT induced varying degree of pulmonary inflammation, in terms of lymphocytic aggregates, granulomas and macrophage infiltration, whereas two thick and straight MWCNT did not. By multiple regression analysis, larger diameter and higher content of iron predicted less histopathological changes, whereas higher cobalt content significantly predicted more histopathological changes. No MWCNT‐related fibrosis or tumours in the lungs or pleura was found. One thin and entangled MWCNT induced increased levels of DNA strand breaks in liver; however, no physicochemical properties could be related to genotoxicity. This study reveals physicochemical‐dependent difference in MWCNT‐induced long‐term, pulmonary histopathological changes. Identification of diameter size and cobalt content as important for MWCNT toxicity provides clues for designing MWCNT, which cause reduced human health effects following pulmonary exposure.     

Radiolabeling,quality control,biodistribution, and imaging studies of 177Lu‐ibandronate

The purposes of this study were as follows: (1) to radiolabel ibandronic acid (IBA, a third‐generation bisphosphonate) with ¹⁷⁷Lu, investigating optimal labeling conditions, and (2) to analyze biodistribution and imaging properties of intravenous ¹⁷⁷Lu‐ibandronate (¹⁷⁷Lu‐IBA) administered in animals. ¹⁷⁷Lu‐labeled methylene diphosphonate (¹⁷⁷Lu‐MDP) served as a comparator agent. Differing proportions of IBA solution and ¹⁷⁷LuCl₃ solution were combined to determine an optimal ratio for radiolabeling purposes, varying pH, temperature, and time to establish ideal reactivity conditions. Radiochemical purity of the labeled compounds was then assessed by paper chromatography. In vitro and in vivo stabilities were also measured at specific time intervals. In Kunming mice, biodistributions of ¹⁷⁷Lu‐IBA and ¹⁷⁷Lu‐MDP and respective agent activities in various organs were monitored by gamma counter, and we performed single photon computed tomography/computed tomography (SPECT/CT) imaging of ¹⁷⁷Lu‐IBA in normal New Zealand White rabbits. Radiolabeling yields for ¹⁷⁷Lu‐IBA proved to be >97% within 30 minutes at 90°C, and its radiochemical purity ensured stability in vitro and in vivo. Furthermore, we found that ¹⁷⁷Lu‐IBA is readily soluble in water, showing higher skeletal uptake than ¹⁷⁷Lu‐MDP but lower uptake by liver and spleen. The image quality of ¹⁷⁷Lu‐IBA was so clear that even after 6 days, analysis was still feasible.     

Preliminary radioimmunoimaging and biodistribution of 131iodine-labeled single-chain antibody fragment against progastrin-releasing peptide(31–98) in small cell lung cancer xenografts

Background Monoclonal antibodies （mAbs） such as DD3,raised against progastrin-releasing peptide（31-98） （ProGRP（31-98）） antigen,have been used to target small cell lung cancer （SCLC）.However,as an intact mAb,DD3 is cleared slowly from the body,with an optimal radioimmunoimaging time of 72 hours.More recently,a singlechain antibody fragment has demonstrated reduced excretion time in blood and normal tissues and is increasingly used in diagnostic cancer research.Thereby,it potentially increases the radioimmunoimaging efficacy.However,there have been few studies with this antibody fragment.The aim of this study was to characterize the preliminary radioimmunoimaging and biodistribution of 1311I-anti-ProGRP（31-98）scFv in nude mice bearing SCLC xenografts.Methods Anti-ProGRP（31-98） scFv was used to detect ProGRP expression by flow cytometry analysis and immunohistochemistry.131I-anti-ProGRP（31-98） scFv was injected intravenously into healthy Kunming mice and the percentage injected dose per gram （%ID/g） in various organs was calculated.Similarly,the %ID/g and tumor/non-tumor ratio in xenograft-bearing mice was calculated.After injection of 131I-anti-ProGRP（31-98） scFv,treated mice were imaged at 1,24,and 30 hours.Then the tumor/base ratios were calculated.Results ProGRP was highly expressed in NCI-H446 cells and xenograft tissue.The metabolism of 131I-anti-ProGRP（31-98） scFv in healthy mice was consistent with a first-order and two-compartment model; T1/2α and T1/2β were 10.2 minutes and 5 hours 18 minutes,respectively.The %ID/g of 131I-anti-ProGRP（31-98） scFv in xenografts was much higher than in healthy tissues at 12 hours after injection,reaching a maximum of （5.38±0.92） %ID/g at 24 hours.Successful imaging of xenograft tissue was achieved as early as 1 hour post-injection and persisted until 30 hours,with 24 hours proving optimal.Conclusion 131I-anti-ProGRP（31-98）scFv shows highly selective tumor uptake with low accumulation in normal tissues and rapid blood clearance,indicating thatit could be a promising agent for SCLC radioimmunoimaging.     

125I标记外泌体在Pan02胰腺癌荷瘤小鼠体内的生物分布研究

目的 旨在开发用 ¹²⁵I-NaI标记外泌体的方法,并通过 γ 计数仪考察其在 Pan02 胰腺癌荷瘤小鼠体内的生物分布特征。方法 通过非放射性 NaI对用于治疗胰腺癌的工程化外泌体进行冷标记,采用透射电子显微镜、纳米粒子跟踪分析和Western blotting实验对标记前后外泌体进行表征。在此基础上采用Iodogen法进行外泌体的放射性 ¹²⁵I-NaI标记,分离纯化后测定 ¹²⁵I-NaI的标记率,Radio-HPLC法测定给药前后 ¹²⁵I-外泌体的放化纯度以考察其稳定性;将 ¹²⁵I-外泌体单次尾iv于Pan02胰腺癌荷瘤小鼠体内,分别于给药后2、6、24、72 h（每个时间点雌雄各3只）经CO₂麻醉后心脏放血处死小鼠,取血清、主要组织器官及肿瘤,γ计数仪测量其放射性计数,计算各组织/血清在不同时间点的蛋白沉淀率;并计算在不同时间点的每克组织（或每毫升血清）放射性计数占总注入放射性计数的百分比（%ID·g^-1或%ID·mL^-1）。结果 外泌体表征的结果显示,标记前后的外泌体形态一致,均成圆形或茶托样结构;标记前外泌体粒径峰值为 113 nm,标记后外泌体粒径峰值为 122 nm,粒径大小主要分布在 50～200 nm;均表达其标志性蛋白 CD63及 TSG101,符合外泌体特征。¹²⁵I-NaI标记外泌体的标记率为 27.82%,纯化后 HPLC法测得即时放化纯度为 100%,给药后放化纯度为（93.34±5.48）%。在小鼠尾 iv给药后 2 h,标记的外泌体主要分布在肝脏［（10.899 2±1.518 1）%ID·g^-1］和脾脏［（2.566 4±0.799 8）%ID·g^-1］,肿瘤中为［（0.291 0±0.056 0）%ID·g^-1］,脑、心脏、脂肪和肌肉组织摄取较少;给药后72 h,肝脏中仍有较高摄取,肿瘤中仍有放射性分布。给药后 2～6 h各组织脏器的蛋白沉淀率较低,表明 ¹²⁵I-NaI标记外泌体稳定性有所降低。结论 外泌体可以进行 ¹²⁵I标记,而且标记同位素前后对外泌体物理形态、生物学活性无明显影响;¹²⁵I标记外泌体的方法简便,标记率和放化纯度均较高;该外泌体产品在荷瘤小鼠体内大部分血流丰富的组织器官均有分布,且具有一定的肿瘤靶向定位能力。     

左旋千金藤啶碱在活体大鼠体内代谢过程的可视化PET/CT显像研究

目的探索通过PET/CT显像将中药有效成分在体内的代谢过程变成可视的图像,并通过图像对其进行定量分析的可行性。方法以延胡索的有效成分左旋千金藤啶碱(L-SPD)作为研究对象。使用正电子核素11碳(11C)标记L-SPD,在热室内化学合成11C-L-SPD。SD大鼠戊巴比妥钠麻醉后固定于木板上,尾iv 37 MBq 11C-L-SPD。分别于注射后5、15、30、45、60、90 min行PET/CT显像。使用工作站获得脑、心脏、肺脏、肝脏、肾脏、肠腔、膀胱的放射性容积分布比值(distribution volume ratios,DVR)。结果 PET/CT显像显示在5 min时11C-L-SPD在肝脏、肾脏分布最多,心脏、肺、脑可见放射性分布。肝、肾是11C-L-SPD的主要代谢及排泄器官,肝、肾、肠腔、膀胱在5 min DVR分别为(1.37±0.42)%、(1.10±0.19)%、(0.89±0.18)%、(0.97±0.11)%,90 min分别为(0.65±0.11)%、(0.54±0.05)%、(5.49±1.44)%、(9.86±1.88)%。结论 PET/CT显像可以直观、动态地观察L-SPD在活体内的分布及代谢特点,有望用于其他中药有效成分的活体显像研究。     

Comparison of small animal CT contrast agents

Non‐invasive in vivo small animal computed tomography (CT) imaging provides high resolution bone scans but cannot differentiate between soft tissues. For most applications injections of contrast agents (CAs) are necessary. Aim of this study was to uncover the advantages and disadvantages of commercially available CT CAs (ExiTron nano 12 000 and 6000, eXIA 160 and 160XL, Fenestra VC and LC) regarding their pharmacokinetics, toxicological side‐effects and the influence of anesthesia on the biodistribution, based on an injection volume of 100 μL/25 g body weight. The pharmacokinetics of the CAs were determined for up to five days. The CA‐induced toxicological/physiological side‐effects were evaluated by determining blood counts, liver enzymes, thyroxine and total protein values, pro‐inflammatory mediators (messenger ribonucleic acid (mRNA)), histology and immunohistochemistry. ExiTron nano 12 000 and 6000 yielded a long‐term contrast enhancement (CE) in the liver and spleen for up to five days. Some of the evaluated CAs did not show any CE at all. Anesthesia did not impair the CAs' biodistribution. The CAs differentially affected the body weight, blood counts, liver enzymes, thyroxine and total protein values. ExiTron nano 12 000 and 6000 induced histiocytes in the liver and spleen. Moreover, ExiTron nano 12 000 and eXIA 160 enhanced tumor necrosis factor (TNF) mRNA expression levels in the kidneys. Thus, we recommend ExiTron nano 12 000 and 6000 when multiple injections should be avoided. We recommend careful selection of the employed CA in order to achieve an acceptable CE in the organs of interest and to avoid influences on the animal physiology. Copyright © 2016 John Wiley & Sons, Ltd.     

多巴胺D2受体PET显像剂~(18)F-Fallypride的临床前实验研究

目的研究多巴胺D2受体显像剂(s)-(-)-N-(1-烯丙基吡咯烷-2-氨基甲基)-5-(3-18F)-2,3-二甲氧基苯甲酰胺(18F-Fallypride)在小鼠体内、脑内的生物分布及安全性。方法ICR小鼠4组(每组5只),尾静脉注射18F-Fallypride注射液(3.7 MBq/0.2 mL),于注射后10、30、601、20 min断头处死,取感兴趣脏器称重,测量放射性计数,计算每克组织百分注射剂量率(%ID/g)及纹状体/小脑值。另取ICR小鼠5只,尾静脉注射18F-Fallypride注射液(3.7 MBq/0.2 mL)),即置microPET全身显像。按中国药典异常考察毒性项下考察18F-Fallypride注射液的安全性。结果体内生物分布及mi-croPET显像均显示18F-Fallypride进入血液后很快被组织摄取,血、心、脾、肺的放射性清除均较快,排泄途径主要为肝、肾、肠、膀胱。在脑组织中药物主要浓聚于纹状体,小脑放射性最低,纹状体/小脑的比值随时间延长而增大1。8F-Fallypride在小鼠体内没有引起明显的毒副反应,安全性能良好。结论18F-Fallypride对多巴胺D2受体具有高特异性结合,靶/非靶比值高,适于脑多巴胺D2受体显像。     

A systematic comparative evaluation of 90Y‐labeled bifunctional chelators for their use in targeted therapy

This paper describes a systematic comparative evaluation of five commonly used bifunctional chelators, namely, p‐isothiocyanato benzyl derivatives of diethylenetriaminepentacetic acid (DTPA‐NCS), trans‐cyclohexyl diethylenetriaminepentacetic acid (CHX‐A″‐DTPA‐NCS), 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA‐NCS), 1,4,7‐triazacyclononane‐1,4,7‐triacetic acid (NOTA‐NCS), and 3,6,9,15‐tetraazabicyclo [9.3.1]pentadeca‐1(15),11,13‐triene‐3,6,9‐triacetic acid (PCTA‐NCS), on the basis of their ability to complex ⁹⁰Y at room temperature, in vitro and in vivo stability and clearance pattern in biological system. The results of the experiments carried out revealed that CHX‐A″‐DTPA‐NCS was the most promising option as it could be radiolabeled with ⁹⁰Y at room temperature with highest specific activity and demonstrated high in vitro stability in human serum and in presence of challenging metal ions commonly present in human plasma. The clearance pattern in Swiss mice revealed that ⁹⁰Y‐CHX‐ A″‐DTPA‐NCS cleared through the kidneys with minimum retention in any other major organ. Thus, the use of cyclohexyl‐DTPA based bifunctional chelators would increase the scope of making ⁹⁰Y‐labeled agents suitable for targeted therapy.     

白蛋白包覆阳离子脂质纳米载体的制备及静脉注射药代动力学和组织分布

溶剂蒸发法制备普通阳离子脂质纳米载体(cNLCs)及白蛋白包覆的脂质纳米载体(BSA-cNLCs),cNLCs和BSA-cNLCs的粒径分别为69.9 nm和80 nm,电位分别为+12.5 mV和+5.02 mV。两者透射电镜照片均呈现圆整类球形结构,且BSA-cNlCs可见明显的白蛋白包覆层。紫杉醇包封率均在97%以上,载药量大于3.7%。加入血浆24 h后,cNLCs粒径增加至原来的1.7倍,而BSA-cNLCs仅增加至1.1倍,包覆白蛋白后血浆稳定性显著提高。高效液相色谱法研究大鼠体内药代动力学及荷瘤小鼠体内组织分布行为,静脉注射BSA-cNLCs 12 h后,大鼠血液中紫杉醇浓度为0.64μg/mL,而cNLCs组则无法检测到紫杉醇;BSA-cNLCs和cNLCs在荷瘤小鼠肿瘤组织中最高浓度分别为8.36μg/mL和2.52μg/mL,12 h后分别降至1.56μg/mL和0.57μg/mL。与cNLCs相比,BSA-cNLCs在血液中的滞留时间显著延长,表现出更好的长循环效果,靶向肿瘤组织的能力增加。