Focal and subtle myelin damage in multiple sclerosis-derived post-mortem human brain slice cultures

Abstract

The mechanisms that drive myelin damage as seen in demyelinating disorders such as multiple sclerosis remain incompletely understood. Much of our current knowledge is derived from animal models, but interspecies differences limit their relevance in the context of human pathology and could explain why various promising preclinical therapies failed during clinical translation. Human post-mortem organotypic brain slice cultures provide a unique platform to study human myelin biology, as they preserve genetic, cytoarchitectural, pathological and species-specific context. Here, we evaluated myelin integrity in a human post-mortem brain organotypic slice culture model and experimentally induce focal myelin damage. Human post-mortem organotypic slices cultures retain key features throughout the culturing period, but exhibit gradual cellular and myelin loss over time. Myelin fibres within the white matter remain detectable and present preserved structural and chemical integrity up to 13 days in vitro, indicated by the conserved paranodal and nodal organization and stable myelin spectroscopic signature. Delivery of lysophosphatidylcholine using cryogel scaffolds enables focal drug administration throughout the full depth of the slice with minimal diffusion into surrounding tissue and induces localized demyelination after lysophosphatidylcholine application. Similar focal application of the selective Nav1.6 stimulator {beta}-mammal scorpion toxin Cn2 induces subtle myelin destabilization. Overall, our results demonstrate the suitability of a human post-mortem brain organotypic slice culture model as an adequate platform for studying myelin damage in a human disease context.