3D In Vitro Blood‐Brain‐Barrier Model for Investigating Barrier Insults

Abstract

Blood-brain-barrier (BBB) disruption has been associated with a variety of central-nervous-system diseases. In vitro BBB models enable to investigate how the barrier reacts to external injury events, commonly referred to as insults. Here, a human-cell-based BBB platform with integrated, transparent electrodes to monitor barrier tightness in real time at high resolution is presented. The BBB model includes human cerebral endothelial cells and primary pericytes and astrocytes in a 3D arrangement within a pump-free, open-microfluidic platform. With this platform, this study demonstrates that oxygen-glucose deprivation (OGD), which mimics the characteristics of an ischemic insult, induces a rapid remodeling of the cellular actin structures and subsequent morphological changes in the endothelial cells. High-resolution live imaging shows the formation of large actin stress-fiber bundles in the endothelial layer during OGD application, which ultimately leads to cell shrinkage and barrier breakage. Simultaneous electrical measurements evidence a rapid decrease of the barrier electrical resistance before the appearance of stress fibers, which indicates that the barrier function is compromised already before the appearance of drastic morphological changes. The results demonstrate that the BBB platform recapitulates the main barrier functions in vitro and can be used to investigate rapid reorganization of the BBB upon application of external stimuli.

Lab-on-a-chip models of the blood–brain barrier: evolution, problems, perspectives

“…39 Where possible, imaging techniques like phase-contrast or fluorescent microscopy, should also be employed for the continuous monitoring of the growth of the cells on the culture surface, and for the validation of the proper, confluent brain endothelial cell layer in the biochip, 4,40 A new BBB-on-chip model by Wei et al integrated barrier monitoring by TEER measurement and fluorescence microscopy in real time. 41 On the other hand, the monitoring of chemical and biochemical signals can be accomplished at separate locations, with connections to the primary BBB module through microfluidic channels. 29,42 It is anticipated, therefore, that we will soon see the creation of modular networks consisting of microfluidic BBB chip and biosensor systems, which will have a wide range of applications in both fundamental, scientific research and practical use.…”

“…5. 4,24,41,101 Reports on whether shear stress increases paracellular tightness at the BBB are somewhat conflicting. In one of the first papers describing a BBB-on-chip device, Booth and Kim found that TEER was elevated by more than 10-fold in response to shear stress (dyn cm −2 not specified).…”

“…5 Types of active and pump-free luminal perfusion systems used to generate fluid flow-induced shear stress in BBB-on-chip devices. 4,24,41,101 Flow rates generated by these methods over time are schematically shown in the lower panels. Drug concentrations were determined by liquid chromatography mass spectrometry (LC-MS).…”

“…39 Where possible, imaging techniques like phase-contrast or fluorescent microscopy, should also be employed for the continuous monitoring of the growth of the cells on the culture surface, and for the validation of the proper, confluent brain endothelial cell layer in the biochip, 4,40 A new BBB-on-chip model by Wei et al integrated barrier monitoring by TEER measurement and fluorescence microscopy in real time. 41…”

Patient‐Derived Microphysiological Systems for Precision Medicine

“…[52,225] Barrier models like the BBB can guide the generation of standardized data from MPS equipped with sensors like TEER around the barrier. [226,227] Researchers can collaboratively develop and share assay methods, incorporating real-time/functional data collection from P-MPS and integrating sensors within the device. [66,228] Third, adopting AI-driven processing for swift and reliable data generation is crucial, as previously discussed.…”