Antioxidant Treatment Prevents Serum Deprivation- and TNF-α-Induced Endothelial Dysfunction through the Inhibition of NADPH Oxidase 4 and the Restoration of β-Oxidation

Abstract

Aims: Oxidative stress plays a pivotal role in the impaired endothelial function occurring in vascular diseases. Antioxidant strategies induce a clinical advantage in patients with endothelial dysfunction and atherosclerosis and protect from oxidative damage, but the underlying molecular mechanisms have been poorly evaluated. The aim of this study was to analyze the effects and mechanisms of action of antioxidant regimens on endothelial function. Methods and Results: Antioxidant efficacy of N-acetylcysteine, ascorbic acid and propionyl-<smlcap>L</smlcap>-carnitine was evaluated in serum-deprived and TNF-α-stimulated human umbilical vein endothelial cells in vitro. Cell adhesion molecule (CAM) expression was evaluated by blot and real-time PCR, and inflammatory cytokine secretion was evaluated by ELISA; leukocyte adhesion and reactive oxygen species assays and NADPH oxidase 4 isoform (Nox4) expression analyses by blots were also performed. Antioxidant pretreatment restored serum-deprived and TNF-α-induced impaired mitochondrial β-oxidation by reducing flavin adenine dinucleotide level and counteracting increased CAM and Nox4 expression, leukocyte adhesion and inflammatory cytokine secretion. Specific inhibition by plumbagin and siNox4 prevented TNF-α- and serum deprivation-induced detrimental effects, confirming that endothelial oxidative stress and inflammation were Nox4 dependent. Conclusions: Our findings documented Nox4 as a main actor in oxidative stress-induced endothelial dysfunction and further clarify the molecular basis of antioxidant treatment efficacy. © 2014 S. Karger AG, Basel

The Role of Maternal Gestational Diabetes in Inducing Fetal Endothelial Dysfunction

“…This theory is supported by the fact that treatment of the diabetic HUVEC with vitamin C (100 μM) inhibited elevated ICAM‐1 expression. Although vitamin C may reduce VEGF expression through reduced HIF1α stability in some systems the evidence in the literature of its effectiveness as an antioxidant was still persuasive for its use in our study Sciolo et al, (). The reduced levels of vitamin C reported in GDM pregnancies (Suhail et al, ) could promote oxidative stress in HUVEC on isolation from umbilical cords, but does not explain the sustained ROS, and elevation of adhesion molecules following cell culture in normoglycaemic conditions.…”

Microvesicles Derived from Inflammation-Challenged Endothelial Cells Modulate Vascular Smooth Muscle Cell Functions

“…Serum deprivation (SD) is also an important apoptotic stimulus contributing greatly to endothelial dysfunction (Scioli et al, 2014). Therefore, co-culture of EC with TNF-α and SD offers a good model to mimicking ischemia and inflammation in ischemic cardiovascular diseases (Wang et al, 2013).…”

Propionyl-L-Carnitine Enhances Wound Healing and Counteracts Microvascular Endothelial Cell Dysfunction

“…Reduction in cutaneous blood flow, oxygen tension, abnormal angiogenesis and increased levels of matrix metalloproteinases (MMPs) and reactive oxygen species (ROS) further support the hypothesis that endothelial cell dysfunction is responsible for impaired wound repair [ 3 ]. Vascular inflammation and increased production of ROS play a pivotal role in endothelial dysfunction [ 8 , 9 ]. ROS are produced by several enzyme systems, including NADPH oxidase (Nox), xanthine oxidase, endothelial nitric oxide synthase, lipoxygenases and myeloperoxidase [ 10 ].…”

“…L-carnitine is an endogenous substance that acts as a carrier for fatty acids across the inner mitochondrial membrane necessary for subsequent β-oxidation and ATP production [ 23 ]. PLC was also documented to be an antioxidant agent, so protecting tissues from oxidative damage [ 8 , 24 , 25 ]. In particular, PLC has been documented to be capable to reduce membrane lipid peroxidation and the effects of hypoxia in cardiomyocytes [ 26 ], endothelial dysfunction in ischemic rabbit limbs [ 24 ] and in human inflammatory bowel diseases [ 25 ].…”

“…In order to document if beneficial effect of PLC on healing process is exclusively related to blood flow recovery or also depends from other mechanisms, we tested the efficacy of PLC in two models of cutaneous wound healing in rat: the skin flap [ 28 ] and full-thickness skin wound [ 29 ]. Since PLC was also documented to ameliorate serum-deprived dysfunction of human umbilical vein endothelial cells (HUVECs) [ 8 , 24 ], we aimed to investigate if beneficial effects of PLC can be extended to cutaneous microcirculation. Our in vivo studies and in vitro data by using human dermal microvascular endothelial cells (HMVECs) strongly support that, in addition to its vasodilatative capacity, PLC accelerates dermal wound healing through its beneficial anti-oxidant effects on microvascular endothelial dysfunction and reparative angiogenesis.…”