背景:用于治疗中枢神经系统(CNS)肿瘤的治疗剂穿过血脑屏障(BBB)的有效递送是开发安全和有效疗法的主要挑战。局部区域药物递送平台通过在靶组织中实现高药物浓度而具有可忽略的全身暴露来提供改进的治疗指数。鞘内(心室内)[IT]和对流增强递送[CED]是两种临床相关方法,用于各种CNS恶性肿瘤。这两个独立平台都受到被动的管理后分配力量的影响,有时限制肿瘤治疗所需的分布。聚焦超声和微泡介导的血脑屏障开放(FUS-BBBO)是用于增强药物递送的最新方式。假定FUS与这些替代递送途径的耦合可以提供益处。多模态FUS可以提供在IT施用后增加实质递送深度的所需能力,并且提供CED的轮廓方向性的手段。Further,用FUS-BBBO实现的瞬时增强渗透率是很好的,但是药物的停留时间和运输时间,对临床剂量计划很重要,尚未定义。本调查包括两个离散的研究:1.进行全面的定量评估,以阐明FUS-BBBO的作用,因为它涉及不同的给药途径(IT和IV),以促进药物在纹状体-丘脑区域内的渗透。2.研究FUS-BBBO与CED联用对药物分布的影响,特别关注目标区域内药物滞留的时间动态。
方法:首先,我们定量评估了FUS-BBBO与IT和IV偶联如何在初始小鼠的预定纹状体-丘脑区域中改变荧光染料(Dextran2000kD和70kDa)的分布和浓度。其次,我们通过测量染料的分布体积和时间依赖性浓度,分析了使用FUS介导的BBB破坏联合CED的药代动力学效应.
结果:我们的结果表明,与FUS-BBBO偶联的IV给药成功地增强了染料向预定义的超声处理靶标的递送。相反,IT给药后,超声目标中可测量的染料始终较少。FUS增强了CED后染料的分布体积。此外,与单独的CED相比,当CED与FUS-BBBO施用偶联时,观察到更短的停留时间。
结论:1.根据我们的发现,与IT施用相比,与FUS-BBBO偶联的IV递送是用于递送至预定空间构象内的深靶标(即纹状体-丘脑区域)的更有效的手段。2.FUS-BBBO增加CED给药后染料的分布体积(Vd),但导致更短的停留时间。这一发现是否可与其他类别的试剂重复(例如,细胞毒性剂,抗体,病毒颗粒,细胞疗法)需要研究。
Efficient delivery of therapeutics across the blood-brain barrier (BBB) for the treatment of central nervous system (CNS) tumors is a major challenge to the development of safe and efficacious therapies. Locoregional drug delivery platforms offer an improved therapeutic index by achieving high drug concentrations in the target tissue with negligible systemic exposure. Intrathecal (intraventricular) [IT] and convection-enhanced delivery [CED] are two clinically relevant methods being employed for various CNS malignancies. Both of these standalone platforms suffer from passive post-administration distribution forces, sometimes limiting the desired distribution for tumor therapy. Focused ultrasound and microbubble-mediated blood-brain barrier opening (FUS-BBBO) is a recent modality used for enhanced drug delivery. It is postulated that coupling of FUS with these alternative delivery routes may provide benefits. Multimodality FUS may provide the desired ability to increase the depth of parenchymal delivery following IT administration and provide a means for contour directionality with CED. Further, the transient enhanced permeability achieved with FUS-BBBO is well established, but drug residence and transit times, important to clinical dose scheduling, have not yet been defined. The present investigation comprises two discrete studies: 1. Conduct a comprehensive quantitative evaluation to elucidate the effect of FUS-BBBO as it relates to varying routes of administration (IT and IV) in its capacity to facilitate drug penetration within the striatal-thalamic region. 2. Investigate the impact of combining FUS-BBBO with CED on drug distribution, with a specific focus on the temporal dynamics of drug retention within the target region.
Firstly, we quantitatively assessed how FUS-BBBO coupled with IT and IV altered fluorescent dye (Dextran 2000 kDa and 70 kDa) distribution and concentration in a predetermined striatal-thalamic region in naïve mice. Secondly, we analyzed the pharmacokinetic effects of using FUS mediated BBB disruption coupled with CED by measuring the volume of distribution and time-dependent concentration of the dye.
Our results indicate that IV administration coupled with FUS-BBBO successfully enhances delivery of dye into the pre-defined sonication targets. Conversely, measurable dye in the sonication target was consistently less after IT administration. FUS enhances the distribution volume of dye after CED. Furthermore, a shorter time of residence was observed when CED was coupled with FUS-BBBO application when compared to CED alone.
1. Based on our findings, IV delivery coupled with FUS-BBBO is a more efficient means for delivery to deep targets (i.e. striatal-thalamic region) within a predefined spatial conformation compared to IT administration. 2. FUS-BBBO increases the volume of distribution (Vd) of dye after CED administration, but results in a shorter time of residence. Whether this finding is reproducible with other classes of agents (e.g., cytotoxic agents, antibodies, viral particles, cellular therapies) needs to be studied.