Causal mechanisms of anesthetic induction and emergence in human cortical organoids

项目总结 该项目旨在使用人类皮质有机体，这是一种在体外产生的皮质样结构，由 人类诱导多能干细胞(HiPSCs)，以解决我们对 麻醉诱导(AI)和麻醉的中尺度现象学背后的原因机制 涌现(AE)。每年有数以百万计的患者接受全身麻醉，但通过这种机制 麻醉药物引起的人工智能的特征至今仍未解决。更鲜为人知的是 大脑从麻醉中苏醒的机制--临床医生对这一过程几乎没有 控制，并经常与并发症有关，如突发性精神错乱，呼吸事件， 以及延迟出现，导致住院时间延长和护理费用增加。此外，1-2 每1000名患者将体验到术中意识和明确的回忆，原因不是 明白了。虽然关于AI和AE的机制已经提出了许多假说， 这些假说仍然存在争议，因为在完整的AI和AE期间，复杂的电路间相互作用 大脑。特别是，人们普遍认为AI的主要原因是大脑皮层GABAA的增强 受体，但很难将皮质GABAA增强的效应从皮质下分离出来 麻醉的影响，这也可能有助于人工智能。同样，尽管人们普遍认为至少 一个，如果不是几个皮质投射的神经调节结构--包括组胺能 下丘脑的结节乳头核、胆碱能的基底前脑、5-羟色胺能的中缝核、 食欲素能下丘脑外侧和去甲肾上腺素能蓝斑-直接驱动从 在麻醉过程中，这些系统紧密相连，相互兴奋。因此，在活体内 研究一直无法确定，如果有的话，这些系统中的哪一个直接导致了AE。一个很有希望的但 完全没有探索过的解决这些问题的工具是人类大脑皮层有机体。我们的团队最近 开发了一种将兴奋性和抑制性皮质样神经元网络融合在一起的方案，这些神经元来源于 HiPSCs。这些融合的皮质类器官可以概括清醒人类的振荡电活动。 我们的初步结果表明，这些皮质类器官可以模拟中尺度的特征 AI当他们接触到麻醉剂异丙酚时。重要的是，皮质类器官由纯皮质- 像人类组织一样，不受皮质下结构或神经调节系统的任何影响。这使得 美国将使用人类皮质有机体来分离AI和AI的皮质和非皮质原因机制 天哪。脑有机体中人工智能和声发射的成功建模将说明这些结构在高级研究中的应用。 用于诱导麻醉或苏醒的新型药物的吞吐量筛选，甚至 在单个病人的基础上。此外，该项目将确定人脑有机化合物在 筛选其他无意识状态的治疗方法，如昏迷和持续性植物人状态。

PROJECT SUMMARY This project aims to use human cortical organoids, which are cortex-like structures generated in vitro from human induced pluripotent stem cells (hiPSCs), to resolve outstanding questions in our understanding of causal mechanisms underlying the mesoscale phenomenology of anesthetic induction (AI) and anesthetic emergence (AE). Millions of patients undergo general anesthesia every year, but the mechanisms by which anesthetic drugs give rise to the hallmarks of AI remain unresolved. Even less well understood are the mechanisms by which the brain emerges from anesthesia - a process over which clinicians have almost no control, and which is frequently associated with complications such as emergence delirium, respiratory events, and delayed emergence, which results in prolonged hospital stays and increased cost of care. In addition, 1-2 per every 1000 patients will experience intraoperative awareness with explicit recall, for reasons that are not understood. While a number of hypotheses regarding the mechanisms of AI and AE have been put forward, these hypotheses are still debated because of complex inter-circuit interactions during AI and AE in the intact brain. In particular, it is widely believed that the major cause of AI is the potentiation of cortical GABAa receptors, but it has been difficult to disentangle the effects of cortical GABAa potentiation from the subcortical effects of anesthesia, which may likewise contribute to AI. Similarly, though it is generally believed that at least one, if not several cortically projecting neuromodulatory structures - including the histaminergic tuberomammillary nucleus of the hypothalamus, the cholinergic basal forebrain, the serotonergic raphe nuclei, the orexinergic lateral hypothalamus, and the noradrenergic locus coeruleus - directly drive emergence from anesthesia, these systems are densely interconnected and mutually excitatory. For this reason, in vivo research has been unable to resolve which, if any, of these systems directly cause AE. A promising but completely unexplored tool for resolving these questions are human cortical organoids. Our team has recently developed a protocol for fusing together networks of excitatory and inhibitory cortical-like neurons derived from hiPSCs. These fusion cortical organoids can recapitulate the oscillatory electric activity of the awake human cortex, and our preliminary results suggest that these cortical organoids can mimic the mesoscale hallmarks of AI when they are exposed to the anesthetic propofol. Importantly, cortical organoids consist of purely cortical- like human tissue, and lack any influence from subcortical structures or neuromodulatory systems. This allows us to use human cortical organoids to isolate cortical versus non-cortical causal mechanisms of both AI and AE. Successful modeling of AI and AE in brain organoids would illustrate the utility of these structures in high- throughput screening of novel drugs for inducing anesthesia or emergence from anesthesia, potentially even on a single-patient basis. Additionally, this project would establish the potential for human brain organoids in screening therapies for other states of unconsciousness, such as coma and persistent vegetative states.