Andre Obenaus1,2, Stephan Ashwal3,
Jerome Badaut Badaut3
1Radiation Medicine, Loma Linda
University, Loma Linda, CA, United States; 2Radiology, Loma Linda
University, Loma Linda , CA, United States; 3Pediatrics, Loma
Linda University, Loma Linda, CA, United States
Diffusion
weighted MRI is widely used in clinical diagnosis. To date the underlying
molecular mechanism responsible for changes in the apparent diffusion
coefficient (ADC) are poorly understood. Using small interference RNA
directed against the astrocytic water channel, acqueporin-4 (AQP4), we were
able to demonstrate a 50% decrease in ADC values when AQP4 expression was
silenced (25%). Thus, astrocytic AQP4 contributes significantly to the ADC
values in normal rodent brain. These results suggest new possibilities for
interpreting ADC values in normal brain and under pathological conditions.