Anti-Aquaporin 4 Antibody

Aquaporin-4 (AQP4), a bidirectional water channel protein, is the most expressed aquaporin within the central nervous system. AQP4 is predominantly expressed by astrocytes and ependymal cells within the blood-brain-barrier and ependymal-cerebrospinal fluid barriers (Verkman, et al 2011). AQP4 plays a role in synaptic plasticity (Skucas et al, 2011), astrocyte mitigation (Saadoun et al, 2005), and K+ homeostasis (Binder et al, 2006). Due to the significant role AQP4 plays in cognition, it has been reported to be dysregulated in several neurological disorders. Alzheimer’s patients have amyloid deposits in the walls of the vasculature known as CAA which causes AQP4 mis-location (Wilcock et al, 2009). Patients with Parkinson’s disease have low levels of AQP4 expression which leads to reduced inflammatory response (Chi et al,2011). Reduced levels of AQP4 in traumatic brain injury affects both the acute stage, decreasing the ability to remove excess water from the brain, and in the later stage, by preventing cellular damage and swelling (Zhang et al, 2015).