Sawai K, Mahato R I, Oka Y, Takakura Y, Hashida M
Department of Drug Delivery Research, Faculty of Pharmaceutical Sciences, Kyoto University, Japan.
J Pharmacol Exp Ther. 1996 Oct;279(1):284-90.
The objective of this study was to clarify the renal disposition characteristics of a 20-mer model phosphodiester oligonucleotide and its partially (PS3) and fully (PS) phosphorothioated derivatives, in isolated rat perfused kidney. Venous outflow and urinary excretion pattern, as well as tissue accumulation of radioactivity after bolus injection of 32P-labeled oligonucleotides, were evaluated under both filtering and nonfiltering conditions. The binding affinity of oligonucleotides to bovine serum albumin in the perfusate increased as the number of sulfur atoms present in the oligonucleotide molecules increased, resulting in 21, 60 and 86% binding to bovine serum albumin for phosphodiester oligonucleotide, PS3 and PS, respectively. The apparent steady-state distribution volumes of the oligonucleotides, as calculated from the venous outflow patterns, were larger than that of inulin, which corresponds to the extracellular volume of the kidney, suggesting their interaction with tissue from the vascular space. PS showed the largest distribution volume. Urinary excretion of oligonucleotides was greatly restricted, compared with that of inulin, which was used as a marker of glomerular filtration rate. The accumulation of these oligonucleotides was ascribed to both tubular reabsorption and uptake from the capillary side. The uptake of oligonucleotides from the capillary side increased as the number of sulfur atoms present in the molecules increased, suggesting sulfur atom-dependent interactions between oligonucleotides and renal tissue. In addition, the uptake of PS3 was a saturable process. Furthermore, coadministration of dextran sulfate and polyinosinic acid inhibited the renal uptake of PS3, whereas polycytidic acid and 4-acetamido-4'-isothiocyanato-stilbene-2,2'-disulfonic acid did not, suggesting that oligonucleotides were taken up via the scavenger receptor-mediated process for polyanions. These findings provide valuable information for the development of delivery systems for antisense oligonucleotides.
本研究的目的是阐明一种20聚体模型磷酸二酯寡核苷酸及其部分（PS3）和完全（PS）硫代磷酸化衍生物在离体大鼠灌注肾中的肾脏处置特征。在滤过和非滤过条件下，评估了静脉流出和尿排泄模式，以及推注32P标记的寡核苷酸后放射性在组织中的蓄积情况。随着寡核苷酸分子中硫原子数量的增加，灌注液中寡核苷酸与牛血清白蛋白的结合亲和力增强，磷酸二酯寡核苷酸、PS3和PS与牛血清白蛋白的结合率分别为21%、60%和86%。根据静脉流出模式计算，寡核苷酸的表观稳态分布容积大于菊粉（对应肾脏细胞外液容积）的表观稳态分布容积，提示它们与血管空间的组织存在相互作用。PS的分布容积最大。与作为肾小球滤过率标志物的菊粉相比，寡核苷酸的尿排泄受到极大限制。这些寡核苷酸的蓄积归因于肾小管重吸收和从毛细血管侧的摄取。寡核苷酸从毛细血管侧的摄取随着分子中硫原子数量的增加而增加，提示寡核苷酸与肾组织之间存在硫原子依赖性相互作用。此外，PS3的摄取是一个可饱和过程。此外，同时给予硫酸葡聚糖和聚肌苷酸可抑制PS3的肾脏摄取，而聚胞苷酸和4-乙酰氨基-4'-异硫氰酸根合芪-2,2'-二磺酸则无此作用，提示寡核苷酸是通过清道夫受体介导的多阴离子摄取过程被摄取的。这些发现为反义寡核苷酸递送系统的开发提供了有价值的信息。
