AQP4 and cerebral infarction: Specifically, AQP4 antibodies can play a role in inhibiting AQP4 expression, which alleviates edema.[9] Once a cerebral infarction occurs, AQP4 antibodies can also down-regulate the expression of the glutamate transporter EAAT2, which causes glutamate circulation disorders and results in a more severe infarction.[7]