Engineering an in vitro model of demyelinated spinal cord tissue
Demyelinating diseases are a group of complex neurodegenerative disorders characterized by damage to the myelin, the protective sheath that insulates and supports efficient nerve signal conduction. Such a loss of myelin causes the formation of lesions not only in the brain but also often in the spinal cord (SC). Despite the high prevalence of SC lesions among patients, existing models mostly focus on those in the brain, inadequately capture the unique anatomical and physiological features of SC pathology. In this study, we developed a robust, reproducible in vitro model of SC demyelination by combining microwell technology and piezoelectric scaffolds to engineer human neural stem cell (hNSC)-derived nerve tissues featuring aligned, myelinated, extended axons up to 2000 {micro}m in length. We utilized distinct chemical treatments to induce demyelination with or without axonal degeneration: a cuprizone cocktail, a copper chelator combined with inflammatory cytokines, and lysophosphatidylcholine (LPC). Electrophysiological assessments validated the physiological relevance of our model, demonstrating impaired signal transmission and neural connectivity akin to in vivo demyelination pathology. Our versatile platform thus provides a valuable tool for elucidating SC demyelination pathophysiology and exploring potential therapeutic interventions.