Expression patterns of aquaporins 1 and 4 in stroke

Ischemic stroke occurs through embolic or thrombotic obliteration of an artery from cerebral circulation and represents over 80% of all stroke cases. One of the fiercest complications after stroke is edema, which results from imbalanced water diffusion around the blood vessels walls. Water diffusion around blood vessel walls occurs physiologically mainly through two protein-formed pores, namely aquaporins (AQPs) 1 and 4. Here, we compare for the first time the expression patterns and colocalization degrees of the two AQPs in control brain tissue and in peri-ischemic regions, on tissue obtained from eight patients with confirmed ischemic pathology and from five control cases. Our analysis showed that AQP4 is more abundant that AQP1, especially in the cortex and in the organized scar areas. The colocalization of the two markers was high, both located on the astrocytes membranes, but the colocalization degree decreased in the scar peri-ischemic regions. Colocalization with basement membranes was also lower for AQP1 compared to AQP4, in all regions analyzed.