Design and Evaluation of an In Vitro Mild Traumatic Brain Injury Modeling System Using 3D Printed Mini Impact Device on the 3D Cultured Human iPSC Derived Neural Progenitor Cells

Abstract

Despite significant progress in understanding the disease mechanism of traumatic brain injury (TBI), promising preclinical therapeutics have seldom been translated into successful clinical outcomes, partially because the model animals have physiological and functional differences in the central nervous system (CNS) compared to humans. Human relevant models are thus urgently required. Here, an in vitro mild TBI (mTBI) modeling system is reported based on 3D cultured human induced pluripotent stem cells (iPSC) derived neural progenitor cells (iPSC‐NPCs) to evaluate consequences of single and repetitive mTBI using a 3D printed mini weight‐drop impact device. Computational simulation is performed to understand the single/cumulative effects of weight‐drop impact on the NPC differentiated neurospheres. Experimental results reveal that neurospheres show reactive astrogliosis and glial scar formation after repetitive (10 hits) mild impacts, while no astrocyte activation is found after one or two mild impacts. A 3D co‐culture model of human microglia cells with neurospheres is further developed. It is found that astrocyte response is promoted even after two mild impacts, possibly caused by the chronic neuroinflammation after microglia activation. The in vitro mTBI modeling system recapitulates several hallmarks of the brain impact injury and might serve as a good platform for future drug screening.

Unraveling the Mechanobiology Underlying Traumatic Brain Injury with Advanced Technologies and Biomaterials

“…[92] Furthermore, in an mTBI model, repetitive mechanical impact has been shown to induce reactive astrogliosis and glial scar formation. [93] While it is believed that mechanical cues coregulate the phenotype and phagocytosis of macrophages, [94][95][96] how these cues affect microglia functions under the altered brain mechanical microenvironment after TBI needs to be further elucidated. Those microglia and astrocyte mechanobiology will be conducive to our understanding of the chronic consequences of TBI from a braininflammation perspective.…”

“…The devices designed to deliver mechanical impacts, such as cell stretcher and blast-wave generator, are not particularly discussed in this article, and we refer the readers to other articles for those methods. [93,103,104]…”

“…First, one major obstacle to the understanding of CTE etiology is the lack of proper animal models that recapitulate the tau pathology as observed in human CTE, such as perivascular tau deposition, neuritic threads, or astrocytic tangles. [30] To this end, the in vitro 3D neural tissue and organoid culture systems that have reproduced the tau pathology and neuroinflammation are useful tools, [93,[204][205][206] which allow precise control of external force application and careful screening of the mechanical effects in the human CNS cells. Despite some inevitable discrepancies from in vivo conditions, those in vitro models exhibit several advantages, that is, avoiding incompatibility with murine species, reducing animal sacrifice, and offering relatively clean environments for force manipulation.…”

Three-Dimensional Printed Abdominal Imaging Windows for In Vivo Imaging of Deep-Lying Tissues

“…The AIWs were designed in 3D CAD software (Solidworks) and were 3D printed using a DLP-based 3D printer (Figure 1A) and a biocompatible methacrylic/acrylic resin [25,26] (Figure 1E) or an FDM (Figure 1B) 3D printer and a PLA material (Figure 1F), which makes them convenient and inexpensive to make. The materials are also biocompatible and will not cause any adverse effects.…”

Building on a Solid Foundation: Adding Relevance and Reproducibility to Neurological Modeling Using Human Pluripotent Stem Cells

“…Organoids are also being considered as tissue sources for transplantation, though primarily for retinal replacement (Lin et al, 2020 ), due to the increased maturation of cells in 3D structures. Additionally, organoids are proving a robust injury model, whether it be the consequences of reduced oxygen to the brain after systemic injury (Kim M. S. et al, 2021 ) or direct traumatic injury to the brain tissue itself (Shi et al, 2021 ).…”