Abstract
Purpose :
DR exhibits an early inflammatory component that is critical to the progression to later stages of disease. Previously, we have demonstrated an anti-inflammatory capacity of the endogenous lipid mediators, EETs, in TNFα-induced leukocyte adhesion. In this study, we tested the hypothesis that EDPs demonstrate similar efficacy in TNFα-induced leukostasis. We also determined the efficacy of both EET and EDP on palmitic acid- (PA-) induced TNFα production by Müller cells.
Methods :
Human Müller cells were treated with PA (250µM) in the presence or absence of 11,12-EET (0.5µM) or 19,20-EDP (0.5µM) and expression of TNFα was assessed by qRT-PCR. Human retinal microvascular endothelial cells (HRMEC) were treated with TNFα (1ng/ml) in the presence or absence of 11,12-EET or 19,20-EDP with AUDA (10µM), a soluble epoxide hydrolase inhibitor. HRMEC were treated for 4 hours and collected for western blot analysis of VCAM-1 and ICAM-1. Under the same treatment conditions, leukocyte adhesion was assayed using a parallel plate flow chamber (PPFC). To assess retinal leukostasis, C57BL/6 mice received an intravitreal injection of TNFα (50ng/ml) in the presence or absence of 11,12-EET or 19,20-EDP with AUDA. Six hours after injection, animals were perfused with Concanavalin-A, retinas were dissected and flat-mounted, and adherent leukocytes were counted.
Results :
PA induced TNFα expression (24.9-fold; p=0.0101), and 11,12-EET and 19,20-EDP significantly inhibited its expression (88.7% [p=0.0112] and 67.7% [p=0.0374], respectively). 11,12-EET with AUDA significantly inhibited TNFα-induced VCAM-1 (33.6%; p=0.0025) and ICAM-1 (42.7%; p=0.0001) levels. 19,20-EDP with AUDA reduced levels of TNFα-induced VCAM-1 (28.3%; p=0.0105), but not ICAM-1 (29.4%; p=0.1038). 11,12-EET and 19,20-EDP similarly inhibited TNFα-induced leukocyte adhesion in the PPFC assay by 47.6% (p=0.0261) and 50.0% (p=0.0138), respectively. In the mouse retina, 11,12-EET with AUDA reduced TNFα-induced leukostasis by 50.8% (p=0.0215) and 19,20-EDP with AUDA inhibited leukostasis by 99% (p=0.0278).
Conclusions :
EET and EDP both inhibit inflammatory behaviors in Müller cells and retinal endothelial cells, suggesting that they have similar anti-inflammatory capacities. Administering exogenous EET/EDP or promoting their endogenous levels may be a viable therapeutic strategy to prevent early inflammation in DR.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.