GFAP and neuromyelitis optica: Other NMO lesion types, however, particularly in the spinal cord and brainstem show intense inflammation and loss of AQP4 with relative preservation of myelin and activated GFAP-positive astrocytes, suggesting that demyelination is secondary to astrocyte loss rather than the inflammatory response (Roemer et al., 2007; Watanabe et al., 2007).