Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA.
Commun Biol. 2023 Aug 2;6(1):806. doi: 10.1038/s42003-023-05185-3.
The common marmoset monkey (Callithrix jacchus) is a species of rising prominence in the neurosciences due to its small size, ease of handling, fast breeding, and its shared functional and structural brain characteristics with Old World primates. With increasing attention on modeling human brain diseases in marmosets, understanding how to deliver therapeutic or neurotropic agents to the marmoset brain noninvasively is of great preclinical importance. In other species, including humans, transcranial focused ultrasound (tFUS) aided by intravenously injected microbubbles has proven to be a transient, reliable, and safe method for disrupting the blood-brain barrier (BBB), allowing the focal passage of therapeutic agents that do not otherwise readily traverse the tight endothelial junctions of the BBB. The critical gap that we address here is to document parameters to disrupt the BBB reliably and safely in marmosets using tFUS. By integrating our marmoset brain atlases and the use of a marmoset-specific stereotactic targeting system, we conduct a series of systematic transcranial sonication experiments in nine marmosets. We demonstrate the effects of center frequency, acoustic pressure, burst period, and duration, establish a minimum microbubble dose, estimate microbubble clearance time, and estimate the duration that the BBB remains open to passage. Successful BBB disruption is reported in vivo with MRI-based contrast agents, as well as Evans blue staining assessed ex vivo. Histology (Hematoxylin and Eosin staining) and immunohistochemistry indicate that the BBB can be safely and reliably opened with the parameters derived from these experiments. The series of experiments presented here establish methods for safely, reproducibly, and focally perturbing the BBB using tFUS in the common marmoset monkey that can serve as a basis for noninvasive delivery of therapeutic or neurotropic agents.
普通狨猴（Callithrix jacchus）由于其体型小、易于操作、繁殖速度快以及与旧世界灵长类动物具有相似的功能和结构的大脑特征，在神经科学领域的重要性日益凸显。随着越来越多的人关注在狨猴中模拟人类脑部疾病，了解如何无创地将治疗或神经营养剂递送至狨猴大脑具有重要的临床前意义。在其他物种（包括人类）中，经静脉注射微泡后，经颅聚焦超声（tFUS）已被证明是一种短暂、可靠且安全的方法，可破坏血脑屏障（BBB），使治疗剂能够通过聚焦传递，而这些治疗剂通常不易穿过 BBB 紧密的内皮连接。我们在这里要解决的关键问题是记录使用 tFUS 可靠且安全地破坏狨猴 BBB 的参数。通过整合我们的狨猴脑图谱和使用狨猴特异性立体定向靶向系统，我们在 9 只狨猴中进行了一系列系统的经颅超声实验。我们展示了中心频率、声压、脉冲周期和持续时间的影响，确定了最小微泡剂量，估计了微泡清除时间，并估计了 BBB 开放以允许药物通过的持续时间。通过 MRI 对比剂以及体外 Evans 蓝染色报告了体内 BBB 破坏的效果。组织学（苏木精和伊红染色）和免疫组织化学表明，使用从这些实验中得出的参数可以安全且可靠地打开 BBB。本研究中提出的一系列实验建立了使用 tFUS 在普通狨猴中安全、可重复和聚焦地干扰 BBB 的方法，可为治疗或神经营养剂的无创递送提供基础。
