Plasma levels of neuron specific enolase quantify the extent of neuronal injury in murine models of ischemic stroke and multiple sclerosis

Objective: We aimed at validating a plasma biomarker for neuronal damage that can be used in acute and chronic models of neurological diseases. Methods: We investigated two different models, middle cerebral artery occlusion followed by reperfusion and MOG35–55-induced experimental autoimmune encephalomyelitis (EAE). In stroke experiments we measured infarct sizes by magnetic resonance imaging and vital stainings and correlated them with plasma levels of neuron specific enolase (NSE) at different time points after reperfusion. Equally, in EAE experiments, we correlated NSE levels with neurological scores and histopathological damage of axons at different time points. We detected plasma NSE levels by ELISA. Results: Plasma NSE levels correlated significantly with stroke size, EAE score and histopathological damage in EAE. Investigations into the dynamics of neuronal loss over time correlated well with the dynamics of NSE levels. NSE even predicted the onset of EAE, before clinical signs were recordable. Conclusions: Plasma NSE is a valid and simple experimental biomarker that allows quantifying the degree of neuronal injury in a non-invasive approach.