gms | German Medical Science

Objective: Investigation of pathophysiological mechanisms of human disease affecting the CNS, such as epilepsy or neurodegenerative disorders, mostly relies on studies based on human tissue obtained post mortem or by biopsy/surgery and on studies using animal models, cell culture or heterologous expression systems. However, it frequently remains elusive how and if such data can be translated to the human brain. Development of strategies and model systems relying on live human tissue could offer a promising step toward bridging this gap.

Methods: We present the development of a model system based on human cortical slice cultures derived from spare access tissue of epilepsy surgery. Toward this aim we prepared organotypic slices immediately after microdissection. Various culture conditions were tested and the effects of artificial culturing media versus human cerebrospinal fluid (hCSF) were systematically investigated. Extensive studies were carried out to quantify the stability of function and morphology of human pyramidal neurons within human cortical slice cultures. Proof-of-concept experiments taking advantage of viral transduction were performed to assess the feasibility of genetic manipulation of human pyramidal neurons within cultures.

Results: Our data reveal sustained cortical neuronal survival lasting up to several weeks, both on single neuron and on network level, including maintenance of robust action potential generation, synaptic connectivity within human cortical slice cultures and even presence of tonic and phasic network activity. Combined immunohistochemical and electrophysiological approaches demonstrate significant benefits of hCSF over artificial culturing media with regard to both increased structural and electrophysiological viability of slice cultures.

Conclusion: Combination of the described model system with state-of-the-art technology including viral transduction of human neurons, high-resolution confocal and two-photon microscopy together with electrophysiological approaches is applied toward the goal of validating data from non human model systems and to translate such data to the human brain. The focus of interest of ongoing and future studies includes investigation of plasticity mechanisms of human neurons, the impact of epilepsy-causing ion channel mutations on the excitability of human neurons and neuronal networks as well as devising approaches for regeneration of human cortical circuitry.