University of Twente Student Theses


Human neuronal in-vitro model of the ischemic penumbra

Pires Monteiro, ir. A.S. (2019) Human neuronal in-vitro model of the ischemic penumbra.

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Abstract:Ischemic stroke is one of the leading causes of mortality and morbidity in the world. The area that surrounds the irreversibly damaged core of a brain infarct - the penumbra - can successfully recover if the blood perfusion is restored in time. If not, massive cell death occurs. The fact that current treatments aiming at neuronal inhibition are ineffective, combined with the assumption that neuronal activity is crucial for cell survival, rises the hypothesis that neuronal activation can improve penumbral recovery. The recent advent of human induced Pluripotent Stem Cells (hiPSCs) allows studying brain dysfunctions in vitro and might provide more substantial results than rodent models, which cannot fully mimic the unique characteristics of human neurons. Despite the advantages of this technique, no studies on the penumbral recovery have been performed with the use of human neurons. For this reason, the current project aims to test whether stimulation helps the recovery of human neuronal networks after an ischemic event. To do so, an in vitro model of the penumbra was built and the effect of different durations of hypoxia (6 to 48 hours) was assessed in networks coupled to Micro Electrode Arrays (MEAs). Three different stimulation techniques were applied - electrical, optogenetic and chemical (with the use of ghrelin) - and the responses were evaluated in terms of the culture’s disperse activity and synchronicity. Our results show that the survival of hiPSCs derived neurons decreased as a function of the hypoxia duration. Significant differences between synchronicity in the baseline and hypoxia phases were found after 24 hours of low oxygen conditions (p < 0.05). Furthermore, stimulation helped maintaining a higher level of activity when in comparison with untreated cultures (more than a 50% increase in the levels of synchronicity), suggesting that activation can improve recovery. Optogenetic stimulation and ghrelin presented the most significant increase after 24 hours of re-oxygenation when compared to controls (p < 0.05). The fact that stimulation proved to be beneficial is expected to open new perspectives on the successful treatment of patients after stroke.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:44 medicine
Programme:Biomedical Engineering MSc (66226)
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