Hyperosmolality-mediated peritoneal microvascular vasodilation is linked to aquaporin function.

Hyperosmolality-mediated peritoneal microvascular vasodilation is linked to aquaporin function. Adv Perit Dial. 2014;30:63-74 Authors: Zakaria el R, Althani A, Fawzi AA, Fituri OM Abstract Glucose-based peritoneal dialysis (PD) solutions dilate the parietal and visceral peritoneal microvasculature by endothelium-dependent mechanisms that primarily involve hyperosmolality. This PD-mediated dilation occurs by active intracellular glucose uptake and adenosine Al receptor activation, and by hyperosmolality-stimulated glibenclamide-sensitive potassium channels. Both pathways invoke NO as a second messenger for vasodilation. We hypothesized that during crystalloid-induced osmosis, the osmotic water flux through the transendothelial water-exclusive aquaporin 1 (AQP1) channels is the primary mechanism whereby the endothelium is being stimulated to instigate hyperosmolality-driven vasodilation. Four microvascular levels (diameters in the range 6 - 100 microm) were visualized by intravital videomicroscopy of the terminal ileum in anesthetized rats. Microvascular diameters and flow were measured after topical exposure to a 5% hypertonic mannitol or 2.5% glucose-based PD solution, at baseline and after brief tissue pre-treatment (with 0.1% glutaraldehyde for 10 seconds) or after combined tissue pre-treatment and pharmacologic blockade of AQP1 with HgCl2 (100 micromol/L). Vascular endothelial integrity was verified by the response to acetylcholin...
Source: Advances in Peritoneal Dialysis. Conference on Peritoneal Dialysis - Category: Urology & Nephrology Tags: Adv Perit Dial Source Type: research