使用与泛素（UBI）偶联的99mTc标记的PN(2)S-聚乙二醇（PEG）和99mTc-泛素检测小鼠体内的感染部位：一项比较生物分布研究。

Detection of sites of infection in mice using 99mTc-labeled PN(2)S-PEG conjugated to UBI and 99mTc-UBI: a comparative biodistribution study.

作者信息

Meléndez-Alafort Laura, Nadali Anna, Pasut Gianfranco, Zangoni Elena, De Caro Raffaele, Cariolato Luca, Giron Maria Cecilia, Castagliuolo Ignazio, Veronese Francesco M, Mazzi Ulderico

机构信息

Department of Pharmaceutical Sciences, University of Padua, 35131 Padova, Italy.

出版信息

Nucl Med Biol. 2009 Jan;36(1):57-64. doi: 10.1016/j.nucmedbio.2008.10.011.

DOI:10.1016/j.nucmedbio.2008.10.011

PMID:19181269

Abstract

UNLABELLED

The antimicrobial peptide ubiquicidin (UBI) directly labeled with technetium-99m ((99m)Tc) has recently been shown to be specifically taken up at sites of infection; however, its chemical structure is not well defined. To address this problem, the aim of the present study was to label UBI using poly(ethyleneglycol)-N-(N-(3-diphenylphosphinopropionyl)glycyl)-S-tritylcysteine ligand (PEG-PN(2)S) in order to compare its ability to detect infection sites with that of (99m)Tc-UBI.

METHODS

The PN(2)S-PEG-UBI conjugate was prepared and labeled with (99m)Tc, and its radiochemical purity was subsequently assessed. The stability of the conjugate to cysteine challenge and dilution with both saline solution and phosphate buffer was determined and serum stability and protein binding were also assessed. In vivo studies were carried out in healthy mice to study the biodistribution of (99m)Tc-PN(2)S-PEG-UBI and its precursor (99m)Tc-PN(2)S-PEG and in infected mice to compare the uptakes of (99m)Tc-UBI and (99m)Tc-PN(2)S-PEG-UBI at the site of infection using scintigraphic imaging and ex vivo tissue counting.

RESULTS

(99m)Tc-PN(2)S-PEG-UBI was obtained with high radiochemical purity (98+/-1%) and high stability. The amphiphilic nature of the conjugate leads to a tendency to form micellar aggregates that explain the high protein binding values obtained. Biodistribution studies in mice showed low renal clearance followed by a predominant reticuloendothelial system clearance that limits its application in the abdominal area. Statistical analysis revealed no significant difference between (99m)Tc-UBI and (99m)Tc-PN(2)S-PEG-UBI uptake in infected mouse thigh, and the site of infection was clearly visualized using scintigraphic imaging.

CONCLUSIONS

(99m)Tc-PN(2)S-PEG-UBI proved to be as effective as (99m)Tc-UBI in detecting sites of infection; however, the well-defined chemical structure of (99m)Tc-PN(2)S-PEG-UBI makes it a better candidate for clinical imaging of infection.

摘要

未标记

最近研究表明，直接用锝-99m（99mTc）标记的抗菌肽泛杀素（UBI）能特异性地在感染部位摄取；然而，其化学结构尚未明确界定。为解决这一问题，本研究旨在使用聚乙二醇-N-（N-（3-二苯基膦酰丙酰基）甘氨酰基）-S-三苯甲基半胱氨酸配体（PEG-PN(2)S）标记UBI，以便将其检测感染部位的能力与99mTc-UBI进行比较。

方法

制备PN(2)S-PEG-UBI偶联物并用99mTc标记，随后评估其放射化学纯度。测定偶联物对半胱氨酸攻击的稳定性以及在生理盐水和磷酸盐缓冲液中的稀释稳定性，还评估血清稳定性和蛋白结合情况。在健康小鼠体内进行研究，以研究99mTc-PN(2)S-PEG-UBI及其前体99mTc-PN(2)S-PEG的生物分布，并在感染小鼠体内使用闪烁成像和离体组织计数比较99mTc-UBI和99mTc-PN(2)S-PEG-UBI在感染部位的摄取情况。

结果

获得了放射化学纯度高（98±1%）且稳定性高的99mTc-PN(2)S-PEG-UBI。偶联物的两亲性导致其倾向于形成胶束聚集体，这解释了所获得的高蛋白结合值。小鼠体内生物分布研究表明，肾脏清除率低，随后主要是网状内皮系统清除，这限制了其在腹部区域的应用。统计分析显示，感染小鼠大腿中99mTc-UBI和99mTc-PN(2)S-PEG-UBI摄取之间无显著差异，并且使用闪烁成像能清晰地观察到感染部位。