Synaptic injury in the inner plexiform layer of the retina is associated with progression in multiple sclerosis
Christian Cordano, Sebastian Werneburg, Ahmed Abdelhak, Daniel J. Bennett, Alexandra Beaudry‐Richard, Greg J. Duncan, Frederike Cosima Oertel, W. John Boscardin, Hao Yiu, Nora Jabassini, Lauren Merritt, Sonia Nocera, Jung Hyung Sin, Isaac P. Samana, Shivany Condor Montes, Kirtana Ananth, Antje Bischof, Jorge R. Oksenberg, Roland G. Henry, Sergio E. Baranzini, Michael R. Wilson, Riley Bove, Richard Cuneo, Sasha Gupta, Joseph J. Sabatino, Joanne Guo, Simone Sacco, Nico Papinutto, Jill A. Hollenbach, Jeff Gelfand, Sam Pleasure, Scott S. Zamvil, Douglas S. Goodin, Emmanuelle Waubant, Refujia Gomez, Gabriel Cerono, Bardia Nourbakhsh, Stephen L. Hauser, Bruce Cree, Ben Emery, Dorothy P. Schafer, Jonah R. Chan, Ari Green
Abstract
While neurodegeneration underlies the pathological basis for permanent disability in multiple sclerosis (MS), predictive biomarkers for progression are lacking. Using an animal model of chronic MS, we find that synaptic injury precedes neuronal loss and identify thinning of the inner plexiform layer (IPL) as an early feature of inflammatory demyelination-prior to symptom onset. As neuronal domains are anatomically segregated in the retina and can be monitored longitudinally, we hypothesize that thinning of the IPL could represent a biomarker for progression in MS. Leveraging our dataset with over 800 participants enrolled for more than 12 years, we find that IPL atrophy directly precedes progression and propose that synaptic loss is predictive of functional decline. Using a blood proteome-wide analysis, we demonstrate a strong correlation between demyelination, glial activation, and synapse loss independent of neuroaxonal injury. In summary, monitoring synaptic injury is a biologically relevant approach that reflects a potential driver of progression.