Roles of NADPH oxidase and mitochondria in flow‐induced vasodilation of human adipose arterioles: ROS‐induced ROS release in coronary artery disease

Abstract

Objectives Hydrogen peroxide (H2O2) contributes to flow-induced dilation (FID) of human arterioles. This study is designed to examine the roles of mitochondria and NADPH oxidase in modulating the release of ROS and in mediating FID. We tested whether NADPH oxidase contributes to mitochondrial ROS generation in arterioles during coronary artery disease (CAD). Methods Visceral adipose arterioles obtained from patients with or without CAD were cannulated and pressurized for videomicroscopic measurement of arteriolar diameters. Dilator responses and ROS production during flow were determined in the presence and absence of the NADPH oxidase inhibitor gp91ds-tat and the mitochondrial electron transport inhibitor rotenone. Results Both dilation and H2O2 generation during flow were reduced in the presence of rotenone (13.5±8% vs. 97±17% without rotenone) or gp91ds-tat in patients with CAD, while patients without CAD exhibited H2O2-independent dilations. Mitochondrial superoxide production during flow was attenuated by gp91ds-tat in arterioles from CAD patients. Conclusions These findings indicate that ROS produced by NADPH oxidase are an upstream component of the mitochondria-dependent pathway contributing to flow-dependent H2O2 generation and dilation in peripheral microvessels from patients with CAD. We conclude that in CAD, both mitochondria and NADPH oxidase contribute to FID through a redox mechanism in visceral arterioles.

Hypercholesterolemia‐Induced Loss of Flow‐Induced Vasodilation and Lesion Formation in Apolipoprotein E–Deficient Mice Critically Depend on Inwardly Rectifying K + Channels

“…Briefly, mesenteric resistance arteries are cannulated on glass micropipettes and pressurized for 1 hour by gravity‐induced pressure (60 cm H 2 O) from solution‐filled reservoirs that perfuse the artery. Arteries are then preconstricted with endothelin‐1 and increasing levels of intraluminal flow administered by moving reservoirs in equal and opposite directions, thus maintaining intraluminal pressure while flow through the vessel increases . No differences are observed between baseline arterial diameters when comparing relevant experimental groups (Table ).…”

“…Dilations to flow were measured as previously described . First‐order mesenteric arteries were cannulated and equilibrated at 60 cm H 2 O for 1 hour in a chamber designed to accept external bath circulated by a peristaltic pump.…”

“…Arteries are then preconstricted with endothelin-1 and increasing levels of intraluminal flow administered by moving reservoirs in equal and opposite directions, thus maintaining intraluminal pressure while flow through the vessel increases. 3,22,31 No differences are observed between baseline arterial diameters when comparing relevant experimental groups (Table S1). As expected, arteries from WT mice dilate in a dose-dependent fashion to increases in flow delivered via the pressure gradient method ( Figure 3A and 3B).…”

“…Dilations to flow were measured as previously described. 3,[21][22][23] First-order mesenteric arteries were cannulated and equilibrated at 60 cm H 2 O for 1 hour in a chamber designed to accept external bath circulated by a peristaltic pump. The pump moves Krebs solution bubbled with O 2 and passes it through a Langendorff to be warmed to 37°C before reaching the chamber.…”

Lysophosphatidic acid acts on LPA1receptor to increase H2O2during flow‐induced dilation in human adipose arterioles

“…In some settings, NOX is the source of LPA‐stimulated ROS (Lin et al ., ). We cannot exclude a role for NOX in FID following LPA treatment, which could occur via ROS‐induced ROS release where small amounts of NOX‐related ROS stimulate release of mitochondrial ROS or vice versa (Zinkevich and Gutterman, ; Zinkevich et al ., ). In fact, a recent study showed LPA 1 and LPA 3 receptor‐dependent activation of PLC, PKC and eventual stimulation of NOX to generate ROS in cell culture model (Lin et al ., ).…”