Page 69 - OR-1-1

more precise model for understanding disease mechanisms holding substantial significance in the field of neuroscience
and drug screening. Velasco et al. further demonstrate that research.
29
BOs derived from different hiPSC lines (PGP1, HUES66, Recent reviews have further highlighted the immense
GM08330, 11a, and Mito 210) consistently generate a potential of BOs in drug screening and disease modeling. 41,42
diverse range of cell types typical of the human cerebral These organoid models not only simulate conditions close
cortex. Immunohistochemistry and scRNA-seq reveal that to human physiology in terms of neurodevelopment,
95% of organoids reproducibly produce nearly identical inflammatory responses, neurodegeneration, and neural
cell types, indicating constrained and reproducible cellular activity but they also facilitate the study of system-level
diversity across hiPSC lines. neural network functions, BBB drug responses, and
The application of hiPSCs in disease modeling is highly toxicity testing. Moreover, organoid models have shown
promising, yet the reprogramming process may introduce promise in high-throughput drug screening, particularly
potential risks. For instance, reprogramming can alter the in their unique ability to mimic the heterogeneity and
DNA methylation profile of cells, potentially increasing invasive behavior of GBM. 43-52 The organoid technology has
their tumorigenic risk. This poses a significant challenge for further demonstrated its broad applicability in the study of
long-term research and clinical application. 30,31 To address neurological diseases (Figure 1).
this issue, scientists are actively exploring strategies to
improve reprogramming techniques, aiming to reduce the 3. Organoids in TBI
potential risks associated with hiPSCs and enhance their 3.1. Structure and microenvironment of TBI
safety and stability. Despite these challenges, the genotype
reconstruction capability and scalability of hiPSCs in 3.1.1. Primary injury
large-scale culture make them a valuable tool for studying Occurring following external mechanical trauma,
CNS diseases. Due to technological advancements, the primary brain injury can be attributed a variety of specific
application of patient-derived hiPSCs models in disease mechanisms, with direct impact of force on intracranial
modeling has achieved a significant growth. Besides, tissues being the primary cause. The main manifestations of
the integration of genomic editing technologies (such as this type of injury include focal contusions accompanied by
CRISPR/Cas9), genetic engineering, and high-throughput hematoma formation, typically occurring in the area of the
single-cell transcriptomics and epigenetics analysis in brain that is directly impacted; white matter shear injuries
organoid development is garnering increasing attention. 32-36 commonly referred to as diffuse axonal injury (DAI), which
BOs, in particular, are receiving more focus as they can characteristically affects the gray-white matter junction
simulate brain development in 3D structures and are used areas of the cerebral hemispheres. In severe cases, DAI may
to study the pathophysiological characteristics of various extend to the corpus callosum and even the brainstem, with
CNS diseases. They provide a new platform for studying prognosis varying depending on the extent of damage to
neurodegenerative diseases (NDDs) such as Alzheimer’s, the ascending reticular activating system, thereby causing
Parkinson’s, and epilepsy, as well as pathological processes focal and global brain edema, which can lead to increased
such as tumors and infections. These emerging technologies intracranial pressure and further affect brain function. 53,54
are not only advancing CNS disease modeling but also
broadening the prospects for developing personalized 3.1.2. Secondary injury
treatment plans. Secondary brain injury evolves over hours to days following
the initial trauma and encompasses a cascade of complex
2.3. Overview of BO models
pathological processes, such as cerebral edema, ischemia-
3D in vitro models constructed from hESCs, hiPSCs, reperfusion injury, disruption of the BBB, neuroinflammatory
hematopoietic stem cells, mesenchymal stem cells responses, mitochondrial dysfunction, and apoptosis. These
55
(MSCs), and neural stem cells (NSCs) have demonstrated processes exacerbate brain tissue damage and increase the
significant potential in the study of pathogenesis and patient’s mortality and morbidity rates. Therefore, secondary
treatment of neurosurgically relevant diseases. Among brain injury is triggered by a chain reaction of molecular
37
these models, BOs, which are derived from induced damage mechanisms. These pathological mechanisms
pluripotent stem cells (iPSC) or hESC aggregates, represent include neurotransmitter-mediated excitotoxicity, primarily
a significant innovation. These organoids simulate the causing neuronal cell membrane damage through the release
microenvironment of the brain and have been extensively of glutamate and free radicals; imbalance of electrolytes,
utilized to study processes such as brain development, particularly excessive influx of calcium ions; mitochondrial
neurogenesis, and neuronal migration. In addition, dysfunction, leading to the disruption of cellular energy
organoid models have been employed to mimic various metabolism; and the activation of inflammatory responses.
disease pathologies, including TBI, GBM, and PD, 38-40 Vascular changes also play a significant role in secondary

Volume 1 Issue 1 (2025) 3 doi: 10.36922/or.8261