DHA Increases Outflow Resistance In Porcine Organ Cultures

Abstract

Purpose: : Caveolae and lipid rafts are highly specialized microdomains of the endothelial plasma membrane which function in signal transduction, endocytosis and transcellular fluid dynamics. Caveolin, a 21 kD protein, is an intergal component in the activity of endothelial cells. Increasing evidence suggests that omega-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA) alter the basic properties of caveolae in endothelia and their function. The purpose of this study was to determine whether DHA changes outflow resistance in porcine anterior segment organ culture and profiles of lipid raft proteins of the trabecular meshwork (TM).

Methods: : Anterior segments of porcine eyes were placed in organ culture and perfused with Dulbecco's modified eagle medium (DMEM). Flow rates were measured in eyes treated with DHA, cavtratin (a synthetic cell permeable peptide corresponding to amino acids 82 through 101 of caveolin: DGIWKASFTIFTVTKYWFYR which is also known as caveolin scaffolding domain), or DMEM. Perturbation of lipid raft containing proteins was assessed by Optiprep density gradient and western blot analysis of dissected TM.

Conclusions: : Infusion of DHA and cavtratin significantly decreased outflow facility and was time-dependent. DHA alters the lipid raft and caveolae microdomain, thereby influencing outflow facility in organ perfusion culture.

Keywords: trabecular meshwork • outflow: trabecular meshwork • lipids