Soluble epoxide hydrolase expression in a porcine model of arteriovenous graft stenosis and anti-inflammatory effects of a soluble epoxide hydrolase inhibitor

Abstract

Synthetic arteriovenous (AV) grafts, placed between an artery and vein, are used for hemodialysis but often fail due to stenosis, typically at the vein-graft anastomosis. This study recorded T lymphocyte and macrophage accumulation at the vein-graft anastomosis, suggesting a role for inflammation in stenosis development. Epoxyeicosatrienoic acids (EETs), products of cytochrome P-450 epoxidation of arachidonic acid, have vasculoprotective and anti-inflammatory effects including inhibition of platelet activation, cell migration, and adhesion. EETs are hydrolyzed by soluble epoxide hydrolase (sEH) to less active diols. The effects of a specific inhibitor of sEH (sEHI) on cytokine release from human monocytes and mouse bone marrow-derived macrophages (BMMΦ) from wild-type (WT) and sEH knockout (KO) animals were investigated. Expression of sEH protein increased over time at the anastomosis as evaluated by immunohistochemistry. Pre-exposure of adherent human monocytes to sEHI (5 μM) significantly inhibited lipopolysaccharide-induced release of monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor-α and enhanced the EET-to-diol ratio. Release of MCP-1 from WT BMMΦ was significantly inhibited but release from sEH KO BMMΦ was not attenuated indicating the specificity of the sEHI. In contrast, sEHI did not inhibit the release of macrophage inflammatory protein-1 or interleukin-6. Nuclear translocation of NF-κB, as assessed by immunocytochemical staining, was not decreased with sEHI in monocytes, but the phosphorylation of JNK was completely abrogated, suggesting this pathway is the target of sEHI effects in monocytes. These results suggest that sEHI may be useful for inhibition of inflammation and subsequently stenosis in AV grafts.

Aberrant Soluble Epoxide Hydrolase and Oxylipin Levels in a Porcine Arteriovenous Graft Stenosis Model

“…Previous work by our group has also shown that macrophage accumulation and cytokine expression are pronounced features of AVG stenosis and that a pharmacological inhibitor of sEH caused a significant decrease in release of monocyte-chemotactic protein-1 and TNF from lipopolysaccharide-stimulated human monocytes in vitro . [40] The data presented herein, together with previous works, suggest that sEH inhibition could be useful for the prevention of AVG stenosis by both targeting inflammation as well as cell migration.…”

“…[40] These intriguing and promising data support the further investigation of oxylipids and sEH in AVG dysfunction.…”

Autologous fat transplants to deliver glitazone and adiponectin for vasculoprotection

“…10-0398). Peripheral blood mononuclear cells (PBMC) were isolated by an adherent method previously described[34]. The PBMC were cultured in 96-well culture plates (2.5 x 10 4 cells/0.3 cm 2 ) with fat/PGZ or fat/ROS culture conditioned media diluted in half with SFM media (Gibco Life Technologies, ThermoFisher Scientific) supplemented with 20% serum.…”

Apelinergic system in endothelial cells and its role in angiogenesis in myocardial ischemia

“…Lu et al [71] found apelin to have the opposite effect on MCP-1, stimulating its expression and secretion in HUVECs via c-Jun NH2-terminal kinase (JNK) and NF-κB. JNK [72,73] and NF-κB [73] have been described to stimulate MCP-1 in other cells, too ( Figure 2). Hence, further research will be needed to reconcile these data, as there can be other factors downstream of apelin/APJ signalling which affect the induction of MCP-1 expression.…”