Stroke constitutes the 5th cause of death in the United States and an important cause of morbidity. During ischemic stroke injury, the blood-brain barrier (BBB, part of the neurovascular unit) is compromised as brain microvascular endothelial cells (BMECs) loose their tight junctions complexes, resulting in the loss of the barrier function, unrestricted entrance of water and ions inside the brain parenchyma and neuronal cell death by excitotoxicity and cerebral edema formation.
Despite the important effort to find neuroprotective agents capable to partially improve neuronal cell survival and restore the BBB function, our ability to translate findings from animal studies to clinical trials is still hampered by an important failure rate. One of the possible caveats we hypothesize that contributes to such important failure rate is the absence of a pre-clinical human model capable to ease the translation. We speculate that a human in vitro model of the neurovascular unit encompassing human BMECs, neurons and astrocytes may help improve such translation.
In this study, we describe a novel in vitro model based on human induced pluripotent stem (iPSCs) cells. Using IMR90-c4 as an iPSC line, we were capable to differentiate BMECs, astrocytes and neurons.
Using oxygen-glucose deprivation (OGD stress), we were able to demonstrate the ability of our iPSC-derived BMECs to respond to such injury by a loss of the cell barrier function similarly, such cellular response was similar to hCMEC/D3 monolayers (an immortalized human BMEC line commonly used). In contrast, iPSC-derived astrocytes showed a remarkable compliance to prolonged OGD stress, showing some consistency with the previous literature. In the other hand, preliminary data obtained with iPSC-derived neurons displayed a rapid decrease in cell viability and increase in cell death suggesting similarities with studies using primary neural cell cultures.
Taken together, we document a differentiation protocol capable to obtain pure iPSC-derived BMECs, astrocytes and neurons lineages allowing us to investigate the cellular and molecular response to stroke injury in vitro. Such model may provide an interesting alternative model to improve our probability to identify novel stroke neuroprotective drug candidates.